Achieving the vision set forth in Chapter 1 requires us to first more fully understand where we are and where we are going and then define and pursue a strategy to accomplish the vision. This chapter reviews the strengths and weaknesses associated with our progress over the last decade, assesses the emerging scientific and societal needs we must serve, and builds from that foundation to identify a strategic framework for the next decade.
PROGRESS SINCE ESAS 2007
In carrying out the 2007 Earth Science and Applications from Space decadal survey (ESAS 2007), participants endeavored to “set a new agenda for Earth observations from space in which ensuring practical benefits for humankind plays a role equal to that of acquiring new knowledge about Earth” (NRC, 2007). The reports Earth Science and Applications from Space: Urgent Needs and Opportunities to Serve the Nation (NRC, 2005) and Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond (NRC, 2007) were the interim and final reports, respectively, that resulted from that effort.
ESAS 2007 called for a set of missions1 (Tables 2.1 and 2.2) and supporting activities that would advance scientific understanding of key processes in the Earth system and provide information to enhance management of natural resources. Recommendations were directed to the National Aeronautics and Space Administration (NASA), National Oceanic and Atmospheric Administration (NOAA), and U.S. Geological Survey (USGS). Progress since the report for each agency is discussed separately in the following text.
1 ESAS 2007 provided recommendations in the form of named missions. In contrast, the statement of task for ESAS 2017 requests recommended science, applications, and observations.
TABLE 2.1 Missions Recommended for NASA (or Joint with NOAA) in ESAS 2007
|Decadal Survey Mission||Mission Description||Orbit||Instruments||Rough Cost (FY 2006 $ Million)|
|CLARREO (NASA portion)||Solar and Earth radiation, spectrally resolved forcing, and response of the climate system||LEO, Precessing||Absolute, spectrally resolved interferometer||200|
|SMAP||Soil moisture and freeze/thaw for weather and water cycle processes||LEO, SSO||L-band radar L-band radiometer||300|
|ICESat-2||Ice-sheet height changes for climate change diagnosis||LEO, non-SSO||Laser altimeter||300|
|DESDynI||Surface and ice-sheet deformation for understanding natural hazards and climate; vegetation structure for ecosystem health||LEO, SSO||L-band InSAR Laser altimeter||700|
|HyspIRI||Land surface composition for agriculture and mineral characterization; vegetation types for ecosystem health||LEO, SSO||Hyperspectral spectrometer||300|
|ASCENDS||Day/night, all-latitude, all-season CO2 column integrals for climate emissions||LEO, SSO||Multifrequency laser||400|
|SWOT||Ocean, lake, and river water levels for ocean and inland water dynamics||LEO, SSO||Ku- or Ka-band radar Ku-band altimeter Microwave radiometer||450|
|GEO-CAPE||Atmospheric gas columns for air quality forecasts; ocean color for coastal ecosystem health and climate emissions||GEO||High-spatial-resolution hyperspectral spectrometer Low-spatial-resolution imaging spectrometer IR correlation radiometer||550|
|ACE||Aerosol and cloud profiles for climate and water cycle; ocean color for open ocean biogeochemistry||LEO, SSO||Backscatter lidar Multiangle polarimeter Doppler radar||800|
|LIST||Land surface topography for landslide hazards and water runoff||LEO, SSO||Laser altimeter||300|
|PATH||High-frequency, all-weather temperature and humidity soundings for weather forecasting and sea-surface temperaturea||GEO||Microwave array spectrometer||450|
|GRACE-II||High-temporal-resolution gravity fields for tracking large-scale water movement||LEO, SSO||Microwave or laser ranging system||450|
|SCLP||Snow accumulation for freshwater availability||LEO, SSO||Ku- and X-band radars K- and Ka-band radiometers||500|
|GACM||Ozone and related gases for intercontinental air quality and stratospheric ozone layer prediction||LEO, SSO||UV spectrometer IR spectrometer Microwave limb sounder||600|
|3D-Winds (Demo)||Tropospheric winds for weather forecasting and pollution transport||LEO, SSO||Doppler lidar||650|
a Cloud-independent, high-temporal-resolution, lower-accuracy sea-surface temperature measurement to complement, not replace, global operational high-accuracy sea-surface temperature measurement.
NOTE: Colors denote mission cost categories as estimated by the committee. Pink, green, and blue shading indicates large-cost ($600 million to $900 million), medium-cost ($300 million to $600 million), and small-cost (<$300 million) missions, respectively. The missions are described in detail in Part II of NRC (2007), and Part III provides the foundation for their selection. LEO, low Earth orbit; SSO, Sun-synchronous orbit; GEO, geostationary Earth orbit.
SOURCE: NRC (2007).
TABLE 2.2 Missions Recommended for NOAA (or Joint with NASA) in ESAS 2007
|Decadal Survey Mission||Mission Description||Orbit||Instruments||Rough Cost (FY 2006 $ Million)|
|CLARREO (instrument reflight components)||Solar and Earth radiation characteristics for understanding climate forcing||LEO, SSO||Broadband radiometers||65|
|GPSRO||High-accuracy, all-weather temperature, water vapor, and electron density profiles for weather, climate, and space weather||LEO||GPS receiver||150|
|XOVWM||Sea-surface wind vectors for weather and ocean ecosystems||LEO, SSO||Backscatter radar||350|
NOTE: Colors denote mission cost categories as estimated by the committee. Green and blue shading indicates medium-cost ($300 million to $600 million) and small-cost (<$300 million) missions, respectively. The missions are described in detail in Part II of NRC (2007), and Part III provides the foundation for their selection. LEO, low Earth orbit; SSO, Sun-synchronous orbit.
SOURCE: NRC (2007).
NASA Progress from ESAS 2007
For NASA, ESAS 2007 recommended 15 missions (including one joint with NOAA) for implementation. As stated in the National Academies’ Midterm Assessment, issued 5 years after publication of the survey (NRC, 2012),
NASA responded positively to the decadal survey and its recommendations and began implementing most of them immediately after the survey’s release. Although its budgets have never risen to the levels assumed in the survey, NASA’s Earth Science Division (ESD) has made major investments toward the missions recommended by the survey and has realized important technological and scientific progress as a result. Several of the survey missions have made significant advances, and operations and applications end users are better integrated into the mission teams. . . . At the same time, the Earth sciences have advanced significantly because of existing observational capabilities and the fruit of past investments, along with advances in data and information systems, computer science, and enabling technologies.
However, the Midterm Assessment authors also found that, for several reasons, the survey vision was being realized at a far slower pace than was recommended.2
Changing priorities and directions from the president and Congress also altered the expected program, notably requiring that NASA restructure its climate observing role. NASA responded to these requests and constraints by designing the Climate-Centric Architecture Plan (NASA, 2010; OIG, 2016), which also provided further guidance for implementing the ESAS 2007 recommendations and augmenting them with other high-priority observations.3 One result of the delayed implementation, and significantly higher costs,
2 From the report: “Although NASA accepted and began implementing the survey’s recommendations, the required budget assumed by the survey was not achieved, greatly slowing implementation of the recommended program. Launch failures, delays, changes in scope, and growth in cost estimates have further hampered the program.”
3 The plan (NASA, 2010) summarized this as follows: “In addition to building the Orbiting Carbon Observatory-2 mission for launch in 2013, NASA will: accelerate development of the four NRC Decadal Survey Tier 1 missions so that they are all launched by 2017; accelerate and expand the Venture-class line of competed, innovative small missions; initiate new space missions to address
of ESAS 2007 missions is that the Midterm Assessment recommended that NASA ESD should implement its missions via a cost-constrained approach, requiring that cost partially or fully constrain the scope of each mission such that realistic science and applications objectives can be accomplished within a reasonable and achievable future budget scenario.4
Consistent with recommendations from the Midterm Assessment, NASA has since included cost-constraints as part of mission definition. The Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission was rescoped as a demonstration on the International Space Station (ISS). Pre-Aerosol, Clouds, and ocean Ecosystem (PACE), a mission from the Climate-Centric Architecture initiative, is being implemented as a directed cost-capped mission.5 As a result, the current number of missions flying and under implementation is different from that noted in the Midterm Assessment (OIG, 2016).
Table 2.3 shows those missions already flying, as well as the anticipated launch dates for missions under implementation. Missions that have a legacy in the ESAS 2007 recommended missions or were selected through the ESAS-recommended Earth Venture program are shown with an asterisk and foundational missions (those that were planned prior to ESAS 2007 and were assumed would be flown) are shown with a double asterisk. Missions in preformulation are not listed. In addition, a number of joint NOAA/NASA missions as well as other “legacy” missions have either launched or are scheduled for launch, but are not listed here. Finally, as noted in Chapter 3 (Table 3.10), the science objectives of several 2007 survey missions are being realized either partially or via an implementation that differs from that originally envisioned. For example, the repeat-pass Interferometric Synthetic Aperture Radar (InSAR) planned for the survey’s Deformation, Ecosystem Structure, and Dynamics of Ice (DESDynI) mission will now be realized via NISAR (NASA-ISRO SAR), a dedicated U.S. and Indian InSAR mission scheduled for launch in 2021, and the GEDI Lidar (Global Ecosystem Dynamics Investigation Lidar) planned for launch to the International Space Station in 2019. Together, these missions will substantially contribute to the high-resolution observations envisioned for DESDynI.
Finding 2.1: The NASA ESD program has made important progress during the decade, partially recovering from the underfunded state it was in a decade ago, and extending the progress noted in the ESAS Midterm Assessment’s conclusion that “NASA responded favorably and aggressively to the 2007 decadal survey.”
- Since the ESAS Midterm Assessment, NASA has adeptly responded to changing requirements and maintained a healthy cadence of Venture suborbital, instrument, and mission opportunities, managed with an improved focus on cost constraints.
- The Earth system science community has benefited from strong international partnerships and satellites exceeding their expected design lifetimes.
- Implementation of pre-decadal and ESAS 2007 missions has been slowed by budgetary constraints, increases in mission costs and scope, and launch failures.
NOAA Progress from ESAS 2007
NOAA’s capability to implement the recommendations of the 2007 decadal survey was hampered by budgetary and programmatic challenges to core elements of its satellite programs, specifically the devel-
continuity of high-priority climate observations; and bring two decadal survey Tier 2 missions forward to allow launch by 2020.”
4 See “Establishing and Managing Mission Costs,” in NAS (2012, pp. 57-59). While not recommending “missions,” the present survey follows a similar approach to constrain the costs of addressing its recommended targeted observables.
5 The PACE mission, directed by NASA’s Goddard Spaceflight Center (GSFC), is defined as a “Design to Cost” development. Details on this type of development may be found in Jeremy Werdell, PACE Project Scientist, “Project Update,” PACE Science Team meeting, January 20-22, 2016, https://pace.oceansciences.org/docs/sci2016_werdell.pdf.
TABLE 2.3 Status of Pre-ESAS 2007 NASA Missions Planned for the 2007-2017 Decade, and Those Entering Implementation or Operations Since ESAS 2007
|OSTM/Jason-2**||Ocean surface topography||Launched 2008, operating|
|Glory**||Aerosol and cloud particle size and optical thickness||Launch failure|
|Aquarius**||Sea-surface salinity||Mission ended|
|Suomi NPP**||Multiple variables (ATMS, VIIRS, CrIS, OMPS, CERES)||Launched 2011, operating|
|LDCM**||Land use and land-surface temperature||Launched 2013, operating|
|GPM**||Precipitation (rain and snow)||Launched 2014, operating|
|OCO-2||CO2||Launched 2014, operating|
|CYGNSS*||Hurricane winds||Launched 2016, operating|
|SMAP*||Soil moisture; freeze/thaw state; surface salinity||Launched 2017, operating|
|SAGE-III (on ISS)||Stratospheric O3, aerosols||Launched 2017, operating|
|GRACE-FO||Changes in gravitational field||In development (2017)|
|ICESat-2*||Ice-sheet elevation change, sea-ice thickness, vegetation canopy height||In development (2018)|
|ECOSTRESS*||Plant temperature and water stress||In development (2018)|
|GEDI*||Ecosystem structure and dynamics||In development (2018)|
|TEMPO*||Air pollution (O3, NO2, . . .)||In development (2018)|
|MAIA*||Aerosols||In development (2021)|
|TROPICS*||Precipitation and storm intensity||In development (2021)|
|GeoCARB*||Carbon exchanges between land and atmosphere||In development (TBD)|
|PACE||Phytoplankton communities||In development (2022)|
|NISAR*||Surface changes from ice-sheet collapse, earthquakes, tsunamis, volcanoes, and landslides||In development (late 2021)|
|SWOT*||Ocean (and freshwater) high-resolution elevation, providing water storage and ocean circulation||In development (2021)|
|CLARREO-Pathfinder on the ISS*||High-accuracy spectral reflectance with on-board calibration||In development (2021 time frame)|
|OCO-3 (on ISS)||CO2||In development (2018)|
NOTE: Missions that have a legacy in the ESAS 2007 recommended missions, or were competed through the ESAS-recommended Earth Venture Program, are shown with an asterisk. Foundational missions are shown with a double asterisk. For future missions, expected launch dates are given in parentheses. Acronyms are defined in Appendix G.
opment of next generation geostationary and polar-orbiting operational environmental satellites, GOES-R and the National Polar-orbiting Operational Environmental Satellite System (NPOESS), respectively.6 Cost growth and delays occurred in both programs; for the polar program, this led to utilization of NASA’s Suomi-NPP for operational data, and the initiation of the Joint Polar Satellite System (JPSS) to replace NPOESS.7
ESAS 2007 recommended that NOAA should restore several key climate, environmental, and weather observational capabilities to its planned NPOESS, now Joint Polar Satellite System (JPSS), and Geostationary Orbit Environmental Satellite-R Series (GOES-R) missions, following descopes to those systems.8 NOAA, with NASA, was able to continue the Clouds and Earth’s Radiant Energy System (CERES)9 time series and restore OMPS for JPSS; however, it was unable to do so for Conical-Scanning Microwave Imager/Sounder (CMIS; microwave imager sounder). NOAA was unable to include a temperature and humidity profiling capability for GOES-R (as described in more detail in Box 4.7, in Chapter 4).
Eventually, as a result of the unanticipated technical problems that led to delays and cost growth, NOAA significantly reduced the scope of the nation’s future polar operational environmental satellite series. This reduction included omitting observational capabilities assumed by ESAS 2007 to be part of NOAA’s future capability and being unable to to implement the three new missions recommended for NOAA implementation by ESAS 2007 (the Operational GPS Radio Occultation Mission,10 the Extended Ocean Vector Winds Mission, and the NOAA portion of CLARREO).
ESAS 2007 also recommended that NOAA should increase investment in identifying and facilitating the transition of demonstrably useful research to operational use. This recommendation was met with mixed results. NOAA was unable to secure funding for an Extended Ocean Vector Winds Mission (XOVWM) for flight on the Japan Aerospace Exploration Agency GCOM-W1 satellite, but it was successful in securing funding for the U.S. contribution to Jason-3 (and launching it on January 17, 2016).11 However, while NOAA will continue to be involved and play a support role, overall U.S. responsibility for continuing the series beyond Jason-3 is reverting back to NASA. The descope of CMIS from JPSS and the lack of follow-on Advanced Microwave Scanning Radiometer (AMSR) are contributing to the potential gap in microwave coverage (this gap is discussed in detail in Box 4.4, in Chapter 4).
Finding 2.2: NOAA progress during the decade was hampered by major programmatic adjustments, as summarized in the ESAS Midterm Assessment’s conclusion that “NOAA’s capability to implement the assumed baseline and the recommended program of the 2007 Decadal Survey have been greatly dimin-
7 The first of the GOES-R satellites was successfully launched on November 19, 2016, and is performing well. At the time of this writing, JPSS-1 is scheduled for launch in late 2017. Notably, throughout the period of planning and development of GOES-R and NPOESS/JPSS, which overlapped the decade since publication of the 2007 decadal survey, and despite technical and budgetary challenges, the recent report by the NOAA National Environmental Satellite, Data, and Information Service Independent Review Team stated, “During this multi-year period, the U.S. weather forecasting and severe storm warning capability has functioned at a high level of performance” (NOAA, 2017, p. 14).
9 The measurements of Earth’s radiation budget provided by CERES instruments since 1998 will now be continued by (1) CERES on the Joint Polar Satellite System-1 (JPSS-1) and (2) the Radiation Budget Instrument (RBI), a scanning radiometer capable of measuring Earth’s reflected sunlight and emitted thermal radiation. RBI will fly on the JPSS-2 mission planned for launch in November 2021, as well as JPSS-3 and JPSS-4. See Georgieva et al. (2015).
10 Many of the objectives of the Operational GPS Radio Occultation Mission were addressed by the FORMOSAT-3/COSMIC mission jointly implemented by NOAA and Taiwan National Space Organization and launched in 2006. A follow-on mission, FORMOSAT-7/COSMIC-2 is scheduled to launch in two phases, with the first launching in 2017. As this report was going to press, NOAA announced it would no longer pursue the second phase of COSMIC-2.
11 The ESAS 2007 report did not explicitly recommend Jason-3; it considered Jason-2 and the NPOESS altimeter series as part of the program of record. When the NPOESS altimeter was descoped as part of the Nunn-McCurdy process, a follow-on NRC report in 2008, Ensuring the Climate Record from the NPOESS and GOES-R Spacecraft (NRC, 2008), identified Jason-3 as a first-tier priority to ensure climate-quality continuity of the altimetry record.
ished by budget shortfalls and cost overruns and by sensor descopes and sensor eliminations on both JPSS and GOES-R.” NOAA’s responsibilities have since evolved to focus on those satellite programs that directly contribute to weather forecasting and warnings and, consequently, it has transferred responsibility for many climate observations to NASA.
USGS Progress from ESAS 2007
The USGS role in space-based observation during the last decade has been significant, built around the 40+ year Landsat program and reinvigoration of this program through the new long-term Sustainable Land Imaging (SLI) partnership with NASA12 and the decision in 2008 to make the Landsat standard data products freely available through the Internet.13 At the time of ESAS 2007 publication, continuity of the Landsat program was a serious concern. Landsat 5 was over 20 years old; Landsat 6 had failed; Landsat 7, launched in 1999, was well beyond its expected lifetime and had been operating since 2003 with a failed scan line corrector;14 and planning for Landsat 8 was not proceeding as needed. The Landsat program had a long history of moving from one agency to another and unsuccessfully changing business models. Building on a National Research Council (NRC) report (NRC, 2013), an interagency study led to a commitment from the administration for a NASA-USGS partnership creating the SLI program and extending the plan for Landsat by two decades. As a result of this attention, the situation has stabilized. Landsat 8 launched in 2013, and Landsat 9 is planned to launch in 2020+.
Finding 2.3: USGS has transformed the Landsat program via the SLI program by operating Landsat, connecting the scientific/user communities and the developers of new measurement technologies, and archiving/distributing data products. This has placed the Landsat measurements on a more operational footing. As long as it is funded and managed as an operational program, the SLI program will support and motivate widespread usage, benefiting both the operational and scientific communities.
Policy Progress from ESAS 2007
The 2007 decadal survey recommended that “the Office of Science and Technology Policy[OSTP], in collaboration with the relevant agencies and in consultation with the science community, should develop and implement a plan for achieving and sustaining global Earth observations. This plan should recognize the complexity of differing agency roles, responsibilities, and capabilities as well as the lessons from the implementation of the Landsat, EOS, and NPOESS programs.”15 The 2014 National Plan for Civil Earth Observations, produced by the National Science and Technology Council (NSTC) and chaired by the Director of OSTP, responds to this recommendation and provides a framework for determining when
12 See NRC (2013). SLI is also described in Tim Newman, Land Remote Sensing Program Coordinator, U.S. Geological Survey, “USGS Land Remote Sensing Program Update: Briefing for the National Geospatial Advisory Committee,” April 7, 2016, https://www.fgdc.gov/ngac/meetings/april-2016/landsat-program-update-ngac-apr-2016.pdf.
13 The benefit of a free archive of Landsat data is discussed in the National Geospatial Advisory Committee paper “Landsat Advisory Group Statement on Landsat Data Use and Charges” (NGAC, 2012). See also Miller et al. (2013).
14 The scan line corrector (SLC) compensates for the forward motion of the satellite. Without an operating SLC, the sensor’s line of sight traces a zigzag pattern along the satellite ground track and an estimated 22 percent of any given scene is lost. A number of methods have been employed to fill the gaps in Landsat 7 data (see USGS, “Landsat 7,” https://landsat.usgs.gov/landsat-7), although for some applications this approach is still not adequate (e.g., see Zhu et al., 2012).
15 See NRC (2007), p. 14. This same recommendation was echoed in a 2008 follow-on report, Ensuring the Climate Record from the NPOESS and GOES-R Spacecraft (NRC, 2008), which further explored in its Chapter 4 the elements needed for a long-term climate strategy.
experimental Earth observations should be transitioned to sustained observations for research or for the delivery of public services. However, executing the transition remains problematic.
As noted earlier, NOAA’s response to the 2007 decadal survey, which included recommendations to sustain a number of measurements, was greatly diminished by budget shortfalls; by cost overruns and delays, especially those associated with the NPOESS program prior to its restructuring in 2010 to become the JPSS; and by sensor descopes and sensor eliminations.16 In 2010, NASA released a Climate-Centric Architecture plan (NASA, 2010) that included a set of “continuity” missions. Further illustrating a much-expanded role for NASA in sustaining observations, the fiscal year 2014 budget of the Obama administration directed NASA to assume responsibility for a suite of climate-relevant observations for the purpose of continuing a multidecadal data record in ozone profiling, Earth radiation budget, and total solar irradiance. This added responsibility, however, has not been accompanied with resources necessary to offset the increased associated expenses. As a result, other activities at NASA are impacted.17
The United States has become increasingly reliant upon the international Earth observing community for maintaining long-term data records essential to understanding the Earth system and how it changes over time. In the 1970s and 1980s, NASA was essentially the sole agency with Earth observing satellites.18 The Europeans and Japanese soon followed. In the 1990s NASA led the way in Earth system science with the Earth Observing System (EOS). Since that time, additional space agencies have developed Earth observing capabilities, and the Committee on Earth Observation Satellites (CEOS)—the primary forum for international space-based Earth observations—has grown to include 32 member organizations. Within the past decade, China and India have both developed ambitious programs. And today, the Europeans—the European Space Agency (ESA), the European Organization for the Exploitation of Meteorological Satellites (EUMETSAT), and the European Union (EU; with its commitment to its Copernicus program)—have become strong and capable organizations, and have established international leadership in implementing sustained global Earth observations.
Finding 2.4: The 2013 National Strategy for Civil Earth Observations and the 2014 National Plan represent progress toward a strategy for achieving and sustaining Earth observations, as recommended by ESAS 2007. However, the United States has not committed the resources to collect the broad range of sustained observations needed to monitor and understand Earth as a system, leaving critical gaps in the implementation of this National Plan and a dependency on non-U.S. sources.
Science and Applications Progress
Scientific and applications progress as a result of the ESAS 2007 report has been substantial. The report articulated challenges in the context of both a general vision for improving science and applications knowledge and specific goals associated with particular science, applications, or societal benefits. Specific progress was anticipated in the areas of (1) Improving Weather Forecasts, (2) Protecting Against Solid-Earth Hazards, (3) Ensuring Water Resources, (4) Maintaining Healthy and Productive Oceans, (5) Mitigating Adverse Impacts of Climate Change, (6) Protecting Ecosystems, and (7) Improving Human Health. Looking back, progress over the last decade has been substantial in these as well as other areas, as a result of continuing access to space-based observations.
18 Russia has had Earth-observing satellites since the 1970s, but access to their data, for all practical purposes, has not been feasible.
Mission Science Example
Scientific progress resulting from the specific missions listed in Table 2.3 is just now being realized, as these missions have been launched and early research results published. The accomplishments of the OCO-2 mission provide an illustrative example.
The OCO-2 Project science objectives include quantifying variations in the column averaged atmospheric carbon dioxide (CO2) dry air mole fraction, XCO2 with the precision, resolution, and coverage needed to improve our understanding of (1) surface CO2 sources and sinks (fluxes) on regional scales (≥1,000 km) and (2) the processes controlling their variability over the seasonal cycle. OCO-2 was launched in July 2014, and these goals are now being addressed. For example, the OCO-2 mission data have now been characterized and calibrated (Crisp et al., 2017; Eldering et al., 2017), and OCO-2 data have been merged with data from the Greenhouse Gases Observing SATellite (GOSAT, now called Ibuki) to provide a more comprehensive data product (Nguyen et al., 2017). Further progress using these data should include improved understanding of the sources and sinks of CO2.19
Scientific progress enabled by satellite observations during the last decade extends far beyond what this committee, in this short review, can assess and communicate. Rather than a comprehensive assessment, we have chosen to provide examples that demonstrate both the progress of the last decade and the opportunity for the next decade.20 To start, eight important examples of progress in the last decade are described in a series of sidebars (boxes) later. The examples and corresponding boxes are as follows:
- Scientific improvements that advanced weather prediction skill (Box 2.1).
- Understanding of air/sea fluxes of sensible and latent heat (Box 2.2).
- Tracking extreme precipitation to reduce disaster risk (Box 2.3).
- Enhanced monitoring to support improvements in U.S. air quality (Box 2.4).
- Tracking sea-level rise and its sources (Box 2.5).
- Monitoring and understanding of stratospheric ozone (Box 2.6).
- Increasing global availability of satellite-based emergency mapping (Box 2.7).
- Satellite ocean color and marine ecosystems—revolutionizing our understanding of life in the sea (Box 2.8).
In addition to these examples highlighted in sidebars, seven other noteworthy examples of progress during the last decade are listed here:
- Quantifying worldwide emissions and concentrations of air pollutants, and their trends. Satellite retrievals from the multi-angle imaging spectroradiometer (MISR) and Moderate-Resolution Imaging Spectroradiometer (MODIS) instruments have been used by Zhao et al. (2017) to document regional trends in Aerosol Optical Depth (AOD) between 2001 and 2015, showing decreases over the Eastern United States and Western Europe. In Eastern and Central China, aerosol AOD increases prior to 2006, fluctuates between 2006 and 2011, and then decreases. These trends appear to be consistent with emissions estimates of aerosol, precursors, and other industrial pollutants.
20 It is also important to recognize that progress in the last decade—and certainly in the earliest part of that decade—is the result of investments made prior to the completion of the decadal survey.
individual cities to plan to adapt to sea-level rise is a prediction for when local sea level will meet or exceed a particular height on the land at that location under various climate scenarios. Planners and engineers urgently need projections of geographically varying sea-level rise as far into the future as possible, they need margins of error associated with the projections (Griggs et al., 2017), and they need to know local rates of vertical land motion. The uncertainty in projections of sea-level rise directly impacts how fast and how much the coast must be hardened, how high streets and piers should be raised, where airports and other infrastructure should be relocated, and/or which neighborhoods should be abandoned.
In many communities, the most dramatic impacts of sea-level rise result from increased vulnerability to coastal flooding. Contributing factors include not only the local sea-level rise, but also storm surges and intense rainfall (e.g., Houston after Hurricane Harvey) and their dependence upon changes in local relative sea level, tidal amplitudes, local subsidence, and the nature of extreme meteorological forces. Coastal flooding manifests itself in the increasing frequency of nuisance floods, such as shown for the city of Boston in Figure 2.5.1.
Evaluating future risks from coastal flooding and inundation—and reducing uncertainties in projections—involves an understanding of how storm frequency and intensity, offshore ocean currents, and decadal variability in the ocean is changing. This in turn depends on maintaining continuing satellite observations of the variables that determine global sea-level rise (changes in ocean heat and land-ice mass), as well as observations of the variables that determine the strength of storm surges (winds, wave height, and tides), intensity of rainfall, and any local subsidence.
Coastal cities and regional governments across the United States—Seattle (Seattle Office of Sustainability and Environment, 2013), San Francisco (City and County of San Francisco, 2016), San Diego (City of San Diego, 2005), Southeast Florida (Southeast Florida Regional Climate Change Compact, 2015), and New York City (City of
Observations from satellites have provided guidance to international policies to protect the ozone layer, starting with the Montreal Protocol, and resulting in the total ban on halocarbon production as of the late 1990s. As illustrated in Figure 2.6.1, satellite observations of ozone over the past decade show that the depletion of the ozone layer has been halted and there are some early signs of recovery. The satellite observations have provided the basis for the development of advanced models to simulate the chemistry of the stratosphere, and model projections for the future are also included in Figure 2.6.1. Satellites will play a central role in the coming decades for monitoring the expected recovery of ozone and the complications associated with climate change.
- Use of satellite data in health impact assessment. The application of satellite retrievals in health impact assessment has been revolutionary and growing rapidly since 2007, relying largely on MODIS, MISR, and related retrievals (Chudnovsky et al., 2013; Kloog et al., 2012, 2014; Liu et al., 2007a, 2007b; Snider et al., 2015). This has been facilitated by both the global coverage from satellites and the improved resolution of estimates of particulate matter (PM)-related properties. Satellite-based estimates of PM exposures are now finer than 1 km, allowing for improved estimates of pollutant health interactions, and the (albeit limited, at present) information from satellites on PM properties is providing information on how specific sources are impacting health.
- Monitoring land-use change due to both human and natural causes. The primary measurements in the SLI suite (Landsat, MODIS, and VIIRS) have sparked substantial research productivity on understanding both processes and features of the land surface, due to both human and natural influences (e.g., Cai et al., 2014). For example, there is newly derived quantification of the global distribution of irrigated and nonirrigated cropland, and of the fact that increased agricultural productivity (ca. 50 percent over the past 50 years) explains up to 25 percent of the observed changes in seasonality of atmospheric CO2 (Gray et al., 2014; Salmon et al., 2015).
- Tracking variations in ocean plankton and land vegetation as well as primary production. SeaWiFS and MODIS-Aqua data were used to provide significant advances in understanding the interannual variability and long-term trends in marine plankton biomass and primary productivity on a global scale as well as the relationship of regional biological variations in plankton biomass and physiology to ocean physical factors such as warming (e.g., Siegel et al., 2013). Similar progress also occurred for quantifying variations in land vegetation greenness and primary production combining satellite multispectral imagery and ecosystem models (Zhu et al., 2011; Anav et al., 2015) as well as the development of new primary production estimation approaches using measurements of solar induced fluorescence (Frankenberg et al., 2014).
- Seeing the rain formation process for the first time on a global scale. Combinations of A-Train observations (the A-Train series of satellites is described in Box 2.9, below) have provided a unique glimpse into one of the important processes of the Earth system—how rain forms (e.g., Suzuki et al., 2010; Takahashi et al., 2017). This revealed many surprises both with respect to how frequently it rains on Earth (Stephens et al., 2010) and exposed significant deficiencies in the way this rain formation process is represented in Earth system models (Golaz et al., 2013; Suzuki et al., 2015), which further underscored the way this process fundamentally shapes the cloud aerosol interactions.
- Cloud feedbacks contributing to the decadal cooling in the eastern tropical Pacific. Zhou et al. (2016) used geostationary satellite observations of clouds and climate model simulations to show how the slowdown in global mean warming that occurred from 1998 to 2013 (Yan et al., 2016) was contributed to by a positive cloud feedback on localized tropical cooling.
- Observation of a slowdown in sea-level rise associated with flooding in Australia. Fasullo et al. (2013) used altimetry, gravity, and color imaging observations from three satellite instruments. It demonstrated that monitoring of sea level and gravity from space is necessary in order to detect a rapid increase in sea-level rise and attribute its causes, consistent with what is expected to happen eventually as the ice sheets begin to decline faster.
Transitioning to the Coming Decade
With Earth science and applications, scientific needs and societal needs are tightly coupled. Curiosity-driven science often leads to significant societal benefits. Science driven by societal needs
often reveals new intellectual challenges of a purely scientific nature. This productive coupling between curiosity-driven science and applications-driven research is a hallmark of Earth system science.
Discipline-specific advances based on observations from space have enabled fundamental discoveries across the natural sciences. In addition, space-based data has provided the foundations for integrated science of the Earth system (Jacobson et al., 2000; Reid et al., 2010; Berger et al., 2012). Many of the important discoveries based on observations from space involve new insight into interactions among major components of the Earth system, for example the atmosphere and oceans (Mechoso et al., 2014), large ice sheets and the oceans (Pritchard et al., 2012; Rignot et al., 2013), ocean circulation and biogeochemistry (Siegel et al., 2014), or terrestrial ecosystems and the water cycle (Wrona et al., 2016). While some discoveries are grounded entirely on observations from space, many more depend on combining information from a range of sources, including field campaigns, laboratory experiments, computer modeling, and theoretical studies (Sellers et al., 1988, 1995; Mechoso et al., 2014). Science based on integrating information from several approaches can lead to products where the insights from the whole are much greater than the sum of the parts. As a consequence, the value of space-based observations amplifies the returns on investments across the Earth sciences.
The top science priorities for the next decade all combine opportunities to drive fundamental science advances as well as contribute to important applications for forecasting, managing, and planning. All fit into a science and technology ecosystem that involves other kinds of measurements as well as theory, with expected returns from the integrated system that amplify the value of each component. Some of the top priorities are important mainly from the perspective of one science discipline or one societal application. Others are critical for a range of disciplines and applications as well as for continued progress in understanding, predicting, and managing the Earth as an integrated system.
A DECADE’S OPPORTUNITY FOR RAPID PROGRESS
A convergence of institutional capacity, technological advance, and scientific discoveries from prior years makes possible rapid progress during the period of this decadal survey.
Institutional Capacity to Meet Scientific and Societal Needs
Since the last decadal survey, the suite of nations with commitments to space-based observation programs has expanded, and a new generation of commercial satellites (especially small commercial satellites) has emerged as a viable option for some kinds of science and applications. Close coordination can facilitate efficiency not only across nations but also between nations and the private sector. Indeed, advances in technology, coordination, and private-sector capabilities have the potential to allow for increased observation capacity within the existing budget constraints. Also, optimal implementation of space-based observation depends on effectively integrating these measurements with measurements from suborbital missions and ground-based measurements and campaigns.
Scientific and Technological Opportunities
The coming decade will present rapidly growing and increasingly challenging needs for Earth information and the science on which it is founded. At the same time, advances in Earth system science, and in other fields that Earth scientists draw from, promise new capabilities that can allow us to progress even more rapidly than we have in the past:
- Advances in space systems technology (such as small spacecraft and active sensing) will allow us to address critical questions in new ways, providing the tools to observe new parameters.
- New scientific methods, such as machine learning, will allow us to extend the reach of our science within limited resources.
- Novel observational methodologies, such as advanced satellite constellations (see Box 2.9), have been shown to significantly amplify the science and applications beyond that which any single satellite provides on its own.
- Innovative project implementation approaches, including rideshare and secondary payload opportunities, spacecraft block buys, public-private partnerships, and international partnerships offer the potential of lower cost missions and/or more frequent access to space.
- Earth process models, data assimilation, and computational capabilities will be sufficiently robust to the point where they can make full use of all the data (tens of terabytes per day) that satellites have to offer, a capacity we cannot currently fully exploit.
- The scientific community and the public have the capacity to effectively absorb new capabilities enabled by the availability of new applications, data structures, and dissemination tools.
- Alternative sources of observations and analytic capabilities are rapidly emerging, particularly in the commercial sector. These can augment traditional sources to enhance capability.
Supported with appropriate resources, NASA, NOAA, and USGS hold the potential to make tremendous advances this decade in both our scientific understanding of Earth and the use of that knowledge to benefit society. Doing so can be best accomplished with a national commitment.
Finding 2.5: This decade presents an opportunity for rapid progress in space-based Earth science and its application to benefit society. The recommended Earth observing system will provide previously unavailable capabilities; new modeling and analysis tools are poised to enable scientific breakthroughs; complementary capabilities are expanding in the commercial sector and other communities; and the research and user community’s ability to deliver benefits is greatly enhanced by technological advances such as widespread Internet access and mobile device use.
A STRATEGIC FRAMEWORK FOR DECADAL PROGRESS
The coming decade is one in which we must not only accelerate the advance of our science and applications, but also do so within constrained resources. This perspective was summarized in the Decadal Community Challenge, as stated in Chapter 1:
Pursue increasingly ambitious objectives and innovative solutions that enhance and accelerate the science/applications value of space-based Earth observation and analysis to the nation and to the world in a way that delivers great value, even when resources are constrained, and ensures that further investment will pay substantial dividends.
A visionary overall strategy is critical for responding to such a difficult challenge. Succeeding requires cost-effectively expanding the benefits of Earth science and the resulting Earth information. Doing so means addressing strategic issues: those high-level issues common to all programs and program elements within each agency and across agencies.
Rising to this challenge requires innovation, not just doing things the way we have in the past but aggressively implementing new means to be efficient and effective in how we work. This ensures we both
address shortfalls in how things are done today and anticipate opportunities to improve given a changing context for the future. As a result, the committee endorses a strategic approach to the U.S program of Earth observation, as summarized in the following recommendation and detailed in the following text.
Recommendation 2.1: Earth science and applications are a key part of the nation’s information infrastructure, warranting a U.S. program of Earth observations from space that is robust, resilient, and appropriately balanced. NASA, NOAA, and USGS, in collaboration with other interested U.S. agencies, should ensure efficient and effective use of U.S. resources by strategically coordinating and advancing this program at the national level, as also recommended in the 2007 Earth Science and Applications from Space (ESAS) decadal survey.
Implementation of this recommendation is discussed in the following two sections of the report.
Toward a National Strategy
To promote national leadership and to develop a national strategy for Earth observation, the inaugural decadal survey report—ESAS 2007—included the following key recommendations:
- The U.S. government, working in concert with the private sector, academe, the public, and its international partners, should renew its investment in Earth-observing systems and restore its leadership in Earth science and applications.
- OSTP, in collaboration with the relevant agencies and in consultation with the scientific community, should develop and implement a plan for achieving and sustaining global Earth observations. This plan should recognize the complexity of differing agency roles, responsibilities, and capabilities as well as the lessons from implementation of the Landsat, EOS, and NPOESS programs.
While considerable progress has been made toward the national strategy envisioned in ESAS 2007, challenges remain and progress needs to continue in order to serve critical national and societal interests. As an example, the nation’s economic and security interests in the applied use of Earth information have been poorly articulated within U.S. policy. Consequently, U.S. agency responsibilities remain unclear in many areas, and the value of the nation’s investments in Earth observation are not being fully realized. This is particularly the case with regard to climate. While the most recent National Space Policy in 2010 emphasized “climate change research and sustained monitoring” to be carried out within NASA, and “climate monitoring” to be carried out within NOAA,21 shifting responsibilities and budgets continue to buffet both agencies.
However, the committee also recognizes the important progress made under the leadership of the National Science and Technology Council, which produced the 2013 National Strategy for Civil Earth Observations and the ensuing 2014 National Plan for Civil Space Observations. These documents defined categories of observations, identified the important observation types within each category, and codified the agency roles for implementing them. To be effective, the U.S. civil strategy needs to be further coordinated with strategies in the defense and intelligence agencies, and supported with adequate funding.
Additional clarification regarding various aspects of the civil strategy has occurred through the budgeting and legislative processes, notably with regard to responsibilities and budgets for climate research
and monitoring. The President’s FY 2011 Budget Request reallocated many climate-related observing responsibilities from NOAA to NASA as part of an administration initiative called the NASA Climate-Centric Architecture, but without concomitant budget shifts. Budget-driven clarification on the roles of NASA and NOAA was included in the President’s FY 2016 Budget Request22 and in the 201623 and 201724 Senate and House Appropriations Committee Reports. Most recently, the Weather Research and Forecasting Innovation Act of 2017 requires NOAA to “prioritize improving weather data, modeling, computing, forecasting, and warnings for the protection of life and property and for the enhancement of the national economy” in the conduct of its research.
Other budget-driven policy constrains possible international partnerships. The 2011 Department of Defense and Full-Year Appropriations Act began an annual process of restricting NASA from bilateral collaboration with China (Hester, 2016), whereas bilateral collaboration between NOAA and China is allowed under the Atmosphere Protocol of the U.S.-China Agreement for Science and Technology originally signed in 1979.25
By its nature, a national strategy for Earth observation involves collaboration with other nations and international coordinating bodies. Among the prominent coordinating bodies are the Coordination Group for Meteorological Satellites (CGMS), the Committee on Earth Observation Satellites (CEOS), and the Global Earth Observing System of Systems (GEOSS). Some, such as the Committee on Space Research of the International Council for Science (COSPAR), even produce their own decadal Earth-system science plans (Simmons et al., 2016). The United States both receives data from other satellites through these collaborations and has obligations to provide its satellite data to other nations. The Program of Record (Appendix A) considered by this committee to represent the foundation of the next decade’s observing system includes a significant set of international satellites formally relied on by the United States within its national Earth observing strategy. Despite successes in international collaboration, access to data from non-U.S. satellites in many cases still presents challenges for U.S. science and applications uses for reasons of policy (as described earlier) or data quality.
In addition, various nongovernmental advisory bodies provide strategic guidance that is valuable to a U.S. national strategy. A 2009 report addressing the entire breadth of U.S. civil space activities (NRC, 2009) listed one of its six strategic goals as “reestablish leadership for the protection of Earth and its inhabitants through the use of space research and technology.” A 2011 report addressed the impediments to interagency collaboration on Earth observation satellites (NRC, 2011), and a 2012 report (NRC, 2012) provided guidance to the National Weather Service regarding actions it should take to progress.
Finally, engagement of the U.S. aerospace and defense industry is essential to accomplishing the priority measurement of this Earth science decadal survey. The use and leveraging of industry provides extensive advantages to the agencies involved and to the U.S. economy (NRC, 2009), and was one of the three major thrusts of the 2012 NRC recommendation for advancing the National Weather Service (NRC, 2012). Beginning with the first Earth weather and observational satellites, U.S. industry has been a reliable and constructive partner and implementing agent for the execution of a wide variety of Earth science mis-
22 “The FY 2016 President’s Budget supports NOAA’s broad environmental mission and redefines NASA and NOAA Earth observing responsibilities whereby NOAA will be responsible for satellite missions that directly contribute to NOAA’s ability to issue weather and space weather forecasts and warnings to protect life and property (Executive Office of the President, 2010).
23 Senate Report 114-66 accompanying FY 2016 CJS Appropriations: “NOAA is directed to prioritize satellite programs directly related to weather forecasting and that result in the greatest reduction of risk to lives and property.” House Report 114-130 accompanying CJS Appropriations for NOAA: “The Committee recommendation focuses limited resources on the Joint Polar Satellite System (JPSS) and Geostationary Operational Environmental Satellite (GOES) program in light of their role in ensuring accurate and timely weather forecasts and warnings.”
24 Similar to the 2016 language, the 2017 House (114-605) and Senate (114-239) CJS Appropriations Reports both direct NOAA to prioritize satellite programs directly related to weather forecasting.
25 See NOAA, “Developing Partnerships,” last modified July 18, 2017, http://www.nesdisia.noaa.gov/developingpartnerships.html.
sions. Greater industry participation, including an increasing emphasis on commercialization within the Earth science enterprise, is expected in coming decades. These benefits are expected over a wide range of scales as a result of increased competition, and from expanded use of public-private partnerships, data buys, and other innovative acquisition models. New entrants and the industrial capabilities in the commercial marketplace are also expected to bring increasing opportunities for technology infusion and cost savings. As these opportunities become increasingly available, governmental agencies need to ensure that commercial data meet the quality standards required for scientific analyses and operational applications, particularly in the area of climate observations for which accuracy, precision, and stability are critical to characterizing and understanding change.
Strategic Challenges and Shortfalls
Each decade presents new opportunities and issues. For the coming decade, optimizing the nation’s investments to achieve a successful Earth observation program, in the expected context of constrained resources, means we must do some things differently from the past. The current programs of NASA, NOAA, and USGS reflect several strategic shortfalls regarding issues that are not being adequately addressed. As long as the following challenges remain unresolved, we will not be able to achieve the full value for the nation of space-based Earth observations.
Observations continuity (scientific and applications). The 2013 National Strategy for Civil Earth Observations and the 2014 National Plan for Civil Space Observations clearly define the category of “sustained observations,” the important observations within that category (including those related to climate), and the agency roles for implementing them. Despite these recent policy clarifications, a national commitment to implementing sustained observations is lacking26 and funding is insufficient to match needs. Overall, it is not clear what roles NASA, NOAA, and USGS play in sustaining long-term space-based observations. Shifting responsibilities, particularly for climate observations, have exacerbated the confusion over agency roles. The commitment in Europe provides a strong contrast; the EU formally committed in 2014 to Copernicus,27 a long-term, user-driven Earth observation and monitoring program focused on the delivery of near-real-time products and services to meet a broad range of societal needs (see Box 3.2, in Chapter 3). This is a commitment not just by a nation, but by the EU, recognizing that the investment is returned many times over in the value it provides to its population and business community.28
NASA and NOAA participate in Copernicus as partners together with ESA, EUMETSAT, and the EU in Sentinel-6, a series of satellites to continue the climate record of sea-level rise. NASA, NOAA, and USGS should continue to interact with ESA, the EU, and other international space agencies to identify shared interests in the continuity of observations as the basis for further collaborative implementation, building on a framework such as that established by Copernicus. It is not just an operational meteorological and land imaging program, but an operational Earth observation program. The United States has no comprehensive equivalent beyond individual elements such as Landsat.
27 European Parliament, “Securing the Copernicus Programme—Why EU Earth Observation Matters,” Briefing, April 2017, http://www.copernicus.eu/sites/default/files/library/EPRS_BRI_Copernicus_matters.pdf. Copernicus includes a space component, and six series of Sentinel missions are expected to be fully operational by 2023, collecting continuous, consistent observations of the Earth for at least a decade.
28 See European Space Agency, “Copernicus: Overview,” http://www.esa.int/Our_Activities/Observing_the_Earth/Copernicus/Overview4.
- Fragmentation. This report addresses three separate U.S. agencies that manage civil Earth observations from space. Other U.S. agencies utilize Earth observation for civilian, military, and intelligence purposes. Even within agencies, Earth observation can be fragmented. In NOAA, for example, observation is mostly separated from the research and operational users of the data, and weather is organized separately from oceans. Improving research-to-operations and research-to-end-use have historically faced significant challenges resulting from institutional stove-piping (NRC, 2000). Fragmentation of roles and responsibilities with U.S. civil Earth observation is a growing issue that will impede progress if not addressed.
- National commitment. A U.S. commitment to Earth observation in support of economic and security progress would provide the stability and prioritization required for efficient long-term planning. ESAS 2007 recommended that Earth information be elevated to a national strategy, a recommendation that has been only partly implemented and deserves further attention (NRC, 2007). Today, such commitment remains inconsistent across agencies, incomplete within agencies, and lacking longterm perspective.
- Managing within resources. While NASA has done an excellent job in developing a program to address the highest priority science needs and objectives, the U.S. civilian space program has insufficient resources to appropriately serve the needs of the nation (for the example of NASA, see Figure 1.4). The resource limitations force a trade between sustained observations needed to characterize and understand changes in the Earth system, and new capabilities aimed at understanding key Earth system processes that directly impact national and societal interests. While restoring appropriate resources is the first choice, the realism of budget constraints implies a need for strategies targeted to greatest success, including new ways of doing business, in the face of inadequate resources.
- Promoting innovation. Government agencies have many requirements and constraints that limit their ability to innovate. While some constraints may be appropriate, in today’s environment innovation has become central to progress. Strategies that break down barriers to innovation are needed, and leveraging of external innovation must be embraced.
Programmatic Impediments and Vulnerabilities
Strategic challenges are often related to tactical, more immediate issues having direct impact on effective program implementation. Of particular importance are institutional and cultural impediments or vulnerabilities that either currently exist or may arise during the next decade. Some of these are internal to the programmatic structure, with strong potential for improvement given recognition of the issue and attention to solutions. Others are external and require planning that anticipates events or decisions outside of programmatic control. Important examples include the following:
- Funding that is insufficient to address program priorities;
- Lack of mechanisms to effectively restructure the overall program, in a manner that faithfully reflects community priorities, when changes are required;
- Changes to the Program of Record due to changes in funding or direction by Congress, or due to changes in partner plans (in particular, the United States is heavily reliant on the ongoing European investment in the Copernicus program, which has become an increasingly important complement to the U.S. program);
- Policy-mandated limitations on collaboration and/or data exchange with potential international partners or data providers;
- Lack of committed resources to collect the specific sustained observations needed to monitor and understand Earth as a system (summarized in general Finding 2.4);
- Institutional and cultural impediments to interagency cooperation;
- Policy, regulatory, and budgetary barriers to integration of commercial technologies and data sources;
- Overreliance on unproven and unlikely technology advances that introduce risk and cost growth;
- Cost growth due to project or mission scope creep or poor cost control; and
- Unanticipated launch or on-orbit failures that lead to reflight decisions and potentially additional budget obligations.
These issues are relevant to development of strategies for the decade, as discussed in this chapter. Equally important, however, is addressing or overcoming specific impediments to more effective programmatic implementation. The new programmatic approaches proposed in Chapter 3 and Chapter 4 are specifically designed to accomplish that, consistent with the Decadal Community Challenge presented in Chapter 1.
This section describes a strategic framework, employing eight elements (Table 2.4), which can help the community meet our ambitious Decadal Community Challenge. It is intended to achieve three objectives: (1) overcome strategic shortfalls from the past; (2) help avoid new strategic shortfalls (cross-agency and cross-program) that threaten to emerge during the decade; and (3) ensure readiness to take advantage of unplanned opportunities for advance and improvement that arise during the decade.
Strategy Element 1—Commit to Sustained Science and Applications
Science generally progresses initially by a first step of exploration that leads to discovery. Often, this is a time-limited process: define and pursue an exploration (such as a space-based mission), publish the resulting science, seek any societal benefits that emerge from the science, and move on to new scientific exploration areas. With this time-limited approach, societal benefits are often ad hoc spin-offs of this process, not explicitly planned but achieved through after-the-fact efforts once the societal value is recognized.
Today, we have come to recognize the important additional discoveries that are obtained when Earth science proceeds beyond initial exploration and commits to sustained science and applications, enabled by
TABLE 2.4 Elements of a Decadal Strategic Framework
|ELEMENTS OF DECADAL STRATEGY|
continuous observing over periods requiring multiple generations of observing spacecraft.29 For example, continuous space-based observations enable the understanding of change in the Earth system occurring over longer timescales than a single spacecraft lifetime. With sustained science and applications, the outcome of an initial exploration (such as a space-based mission) is reviewed for the potential that follow-on missions could produce valuable additional science and applications. In some cases, the additional science involves new discoveries. In others, new science and/or applications emerge as a consequence of extending the length of the observation over multiple years and decades.
By further ensuring that sustained science involves planned implementation of applications, the latency between performing science and achieving societal benefits is reduced. Among NASA’s science portfolio, Earth science is unique in the benefits that can be obtained from commitment to sustained science and applications. Sustained observations are central to the progress of Earth science, and integral to the longterm achievement of societal benefits. As noted earlier, the European Union has embraced sustained science and applications, through its Copernicus program and the underlying Sentinel space-based observations (also described in more detail in Box 3.2, in Chapter 3).
To achieve the needed commitment to sustained science and applications, and to achieve the greatest value from the nation’s investments, roles and responsibilities need to be better defined and implemented for each agency, and resources need to be included in the budgeting process to allow the fulfillment of continuous observations.
The importance of sustaining a growing list of measurements for science and applications (see, for example, Box 4.5, in Chapter 4) and the lack of accompanying growth in the budget suggests that international collaboration must play a key role in any strategy for sustained observations. ESA, EUMETSAT, the European Commission, NASA, and NOAA have recently agreed to ensure the measurement record of global and regional sea-level change through at least two future missions via the Sentinel-6 missions within the Copernicus Program. A systematic approach to identifying measurements requiring long-term continuity (e.g., following NRC, 2015) and which of those are of interest to potential international partners should be undertaken to determine whether similar agreements and/or frameworks are viable as the basis for collaboration on implementation sustained measurement programs.
Recommendation 2.2: NASA—with NOAA and USGS participation—should engage in a formal planning effort with international partners (including, but not limited to ESA, EUMETSAT, and the European Union via its Copernicus Program) to agree on a set of measurements requiring long-term continuity and to develop collaborative plans for implementing the missions needed to satisfy those needs. This effort to institutionalize the sustained measurement record of required parameters should involve the scientific community, and build on and complement the existing domestic and international Program of Record.
Strategy Element 2—Embrace Innovative Methodologies for Integrated Science and Applications
One means to accelerate progress is to seek fundamental methodological advances that are shared across disciplines and pursuits. These hold the potential to advance the field or organization as a whole. Examples include, but are not limited to:
29 The multidecadal Landsat (now Sustainable Land Imaging, or SLI) program is one example. Its 30+ year continuous data set has proven critical for understanding the evolution of Earth’s surface, and for managing resources on that basis. Many examples of the need for sustained science and applications emerged from the Earth Observing System (EOS) program starting in the 1990s, including policy-critical areas such as sea-level rise, water availability, and transport of pollutants.
- Advanced cost-effective observation methodologies. Low-cost observations and methodologies can be used to enhance and/or augment investments in space-based data. Examples include (1) citizen science and community-based observations, (2) ad hoc and distributed observations, as from existing ground networks, automobile sensors, and mobile phones, and (3) observational sampling using compressive sensing (see Box 2.10).
- Advanced analysis methodologies. Investments in innovative analysis capabilities accelerate the ability to convert observations into scientific knowledge. Candidates include (1) data science, including big data analytics and other techniques emerging in the commercial world, (2) a more integrated data analysis system that includes advances in modeling; and assimilation of in situ data and data from multiple satellite sensors.
- Accelerated applications. Accelerating the conversion of science to societal benefits amplifies the societal impact. Candidates include (1) applications included from the early stages of observation planning and development, (2) rapid applications prototyping, (3) rapid transition from science to applications, and (4) promoting the science of applications, to advance applications methodologies (Dozier and Gail, 2009).
Strategy Element 3—Amplify the Cross-Benefit of Science and Applications
Curiosity-inspired science will always be central to Earth observation and analysis. But a growing portion of our science is use-inspired or closely related to the applications it enables. The traditional paradigm for integrating science and applications can be described as pursuing high-quality and innovative science, and then assuming it will somehow find a path to applications. Sometimes referred to as the valley of death between science and end-use (for example, NRC, 2000), or between research and applications, the issue is widely recognized even as this paradigm has been slow to evolve.
Inspiration goes both ways: science inspires applications scientists and engineers, and end-use needs can inspire research scientists and engineers. Embedding science in the applications process often reveals new and inspirational scientific questions driven by those end-uses not well-recognized by research scientists. While we often select our pursuits by using this science-applications thinking in an implicit way, doing so more explicitly can lead to improved outcomes, particularly when resources are constrained.
Among NASA’s diverse and inspirational scientific elements, Earth Science is special in the extent and breadth of its practical benefits to society. To its credit, NASA has increasingly integrated applications into flight programs and research, with results that have been embraced by both the science and applications communities. The SMAP mission has been used as a prototype for a more integrated science/applications team, with positive results. Extending and expanding on this trend will strengthen both science and applications. To accomplish this, programs with both science and applications elements need to explicitly identify the connection, and define opportunities to amplify the cross-benefit, and organization structures and processes need to be adapted when possible to integrate, rather than segregate, science and operations/applications.30
30 Through its Earth Venture-Instruments solicitation, NASA recently announced its first competitively selected mission with societal benefit as its primary objective. The Multi-Angle Imager for Aerosols (MAIA), will investigate the connections between aerosols and human health. From the very beginning, MAIA has involved collaborations with the Environmental Protection Agency (EPA), National Institutes of Health (NIH), Centers for Disease Control and Prevention (CDC), NOAA, and World Health Organization (WHO). See Lin and Diner (2017).
Strategy Element 4—Leverage External Resources and Partnerships
In a constrained resource environment, much can be done by leveraging resources. NASA, NOAA, and USGS have long-established partnerships with non-U.S. space agencies and other organizations, which have already proven highly valuable in bringing additional resources to address their missions (further discussion is included in Chapter 4). In many cases, they also enable access to regional and global observations that would simply be unavailable to U.S. agencies any other way.
Today, there is a strong need to build on and extend those partnerships, and to bring in innovative new partnerships such as commercial data sources. In particular, there is a need to (1) extend and strengthen the already strong international partnerships and (2) leverage the availability of commercial providers for resources traditionally supplied by governments. Specific suggestions for accomplishing that are addressed in this report.
Strategy Element 5—Institutionalize Programmatic Agility and Balance
The demands we will face in the coming decade, and the problems to be solved in order to address them, will arrive at an ever-increasing pace as populations grow, human impacts on the environment continue to increase, and society’s digital information use broadens. NASA, NOAA, and USGS will need to make both large and small programmatic adjustments over short time periods. Agility in programmatic structures, and in the authorities of staff who implement programs, is essential to respond to new discoveries and emerging needs, particularly in the context of resource constraints. At the same time, achieving and maintaining programmatic balance is critical to successful programs.
Agility and balance do not emerge naturally in organizations. They must be explicitly built into the cultures and processes or they risk being overcome by bureaucracy. For example, the software industry moved from the traditional preplanned “waterfall” model to agile software management techniques to more rapidly and effectively advance their products (Kettunen and Laanti, 2008).
With NASA, NOAA, and USGS, the development cycle for space-based observations can be as long as a decade and more, impeding the ability to be responsive to changing needs and emerging science. NOAA and USGS, in their portion of the committee’s statement of task, have specifically sought suggestions for being more agile in terms of integrating new science and technology. This agility is achieved in part through a balanced portfolio that incorporates both long-lead missions and activities as well as shorter-term efforts that can be more responsive to and take advantage of emerging capabilities and opportunities.
Strategy Element 6—Exploit External Trends in Technology and User Needs
Successful organizations formally review and track key enabling trends and proactively incorporate them in their activities.31 Within NASA, NOAA, and USGS, success at anticipating and leveraging trends has been episodic;32 the agencies have been slow at times to leverage external capabilities that could have enhanced their capabilities.
For NASA, NOAA, and USGS, a successful process for exploiting external trends might include, at minimum, a survey of (1) advances in scientific methodologies from outside these agencies; (2) commer-
31 The importance of anticipating trends in the rapidly moving Internet field is well known. A source widely cited is industry analyst Mary Meeker, currently at the venture capital firm Kleiner Perkins, who has publicly released an annual report on Internet trends for many years. See Meeker (2017).
32 There are notable exceptions. NASA has invested for many years in technology advances through the Earth Science Technology Office (ESTO) program, seeking to leverage technology progress within the community, and has embraced use of small satellites and funded advances in small launch vehicles.
cial methods for characterizing the diverse applications and information end-uses of data; (3) observation technology advances in the commercial sector; (4) computing and data methodologies and tools that enable new data analysis approaches; (5) community science, such as crowdsourcing and distributed observations, which has the potential to augment space-based observations; (6) nontraditional partnerships such as philanthropists and nonprofits; (7) innovation in public-private partnerships and acquisition alternatives such as data buys, standardized spacecraft, and system block buys; and (8) human resources and education methods (such as the “boot camps” used widely today to rapidly educate software engineers) targeted at making the workforce more effective.
For example, item (2) reflects the fact that there are so many end-uses of NASA/NOAA/USGS data that the agencies no longer can simply track straightforward metrics like grants or website data requests to know how their data are used. This is the same problem faced throughout the commercial internet world, including by internet leaders such as Google, for understanding their user base. Since there is a clear financial stake in this information, companies are investing in developing solutions that involve more sophisticated metrics and tools, including big data techniques. Federal agencies with similar needs can benefit from these investments.
Strategy Element 7—Expand Use of Competition
Competition has already proven effective in many areas of science and procurement for NASA, NOAA, and USGS as a means of inspiring innovation and creativity and delivering cost-effective approaches to Earth observation. The committee believes these results can be extended even further for Earth science, and we have embraced the use of competition within the structure of our recommendations (see Chapter 3). Competition and collaboration (as noted in Strategy Element 4) are not necessarily in conflict, and both should be used as appropriate.
Strategy Element 8—Pursue Ambitious Science and Applications, Despite Constraints
Constraints do not imply a need to be timid. The committee believes that pursuing ambitious science not only leads to the greatest scientific advances, but it also ensures the greatest likelihood that substantial and often unanticipated societal benefits will emerge. NASA, NOAA, and USGS need to build on their history of pursuing ambitious programs to serve the nation, even when faced with resource challenges. While this requires appropriate scoping to respect constraints, it does not require losing the ability to think big. Maintaining ambition can be accomplished by (1) setting clear and far-reaching goals within all planning processes; (2) explicitly identifying mechanisms that might allow these goals to be pursued despite resource constraints, such as creative implementation approaches; and (3) pursuing ambitious observation system capabilities, such as active sensing systems, while ensuring acceptable risk through targeted technology development as needed.
Anav, A., P. Friedlingstein, C. Beer, P. Ciais, A. Harper, C. Jones, G. Murray-Tortarolo, et al. 2015. Spatiotemporal patterns of terrestrial gross primary production: A review. Reviews of Geophysics 53: 785-818.
Ashouri, H., K.-L. Hsu, S. Sorooshian, D.K. Braithwaite, K.R. Knapp, L.D. Cecil, B.R. Nelson, and O.P. Prat. 2015. PERSIANN-CDR daily precipitation climate data record from multisatellite observations for hydrological and climate studies. Bulletin of the American Meteorological Society 96(1):69.
Auligné, T., R. Gelaro, R. Mahajan, D. Groff, R. Langland, J. Liu, J. Cotton, L. Morgan, and Y. Ota. 2016. “Forecast Sensitivity—Observation Impact (FSOI) Inter-Comparison Experiment.” http://www.wmo.int/pages/prog/www/WIGOS-WIS/reports/6NWP_Shanghai2016/WMO6-Impact-workshop_Shanghai-May2016.html.
Bauer, P., A. Thorpe, and G. Brunet. 2015. The quiet revolution of numerical weather prediction. Nature 525(7567):47-55.
Behrenfeld, M.J., Y. Hu, R.T. O’Malley, E.S. Boss, C. A. Hostetler, D.A. Siegel, J.L. Sarmiento, J. Schulien, J.W. Hair, X. Lu, S. Rodier, A.J. Scarino. 2017. Annual boom-bust cycles of polar phytoplankton biomass revealed by space-based lidar. Nature Geoscience 10:118-122.
Belward, A.S., and J.O. Skøien. 2015. Who launched what, when and why: Trends in global land-cover observation capacity from civilian Earth observation satellites. ISPRS Journal of Photogrammetry and Remote Sensing 103:115-128.
Berger, M., J. Moreno, J.A. Johannessen, P.F. Levelt, and R.F. Hanssen. 2012. ESA’s sentinel missions in support of Earth system science. Remote Sensing of Environment 120:84-90.
Blondeau-Patissier, D., T. Schroeder, V.E. Brando, S.W. Maier, A.G. Dekker, and S. Phinn. 2014. ESA-MERIS 10-year mission reveals contrasting phytoplankton bloom dynamics in two tropical regions of Northern Australia. Remote Sensing 6:2963-2988.
Bourassa, M.A., S. Gille, D.L. Jackson, B.J. Roberts, and G.A. Wick. 2010. Ocean winds and turbulent air-sea fluxes inferred from remote sensing. Oceanography 23(4):36-51.
Bourassa, M.A., S.T. Gille, C. Bitz, D. Carlson, C. A. Clayson, I. Cerovecki, M.F. Cronin, et al. 2013. High-latitude ocean and sea ice surface fluxes: Challenges for climate research. Bulletin of the American Meteorological Society 94:403-423.
Brown, P.J., and C.D. Kummerow. 2014. An assessment of atmospheric water budget components over tropical oceans. Journal of Climate, 27(5):2054-2071.
Buizza, R., and M. Leutbecher. 2015. The forecast skill horizon. Quarterly Journal of the Royal Meteorological Society 141(693):3366-3382.
Cai, H., X. Yang, K. Wang, and L. Xiao. 2014. Is forest restoration in the Southwest China Karst promoted mainly by climate change or human-induced factors? Remote Sensing 6(10):9895-9910.
CEOS (Committee on Earth Observation Satellites). 2015. Satellite Earth Observations in Support of Disaster Risk Reduction. The CEOS Earth Observation Handbook. Special 2015 Edition for the 3rd UN World Conference on Disaster Risk Reduction. http://ceos.org/home-2/eohandbook2015/.
CEOS. 2015. “The CEOS Database.” Accessed December 20, 2015. http://database.eohandbook.com/timeline/timeline.aspx.
Chen, X., X. Zhang, J.A. Church, C.S. Watson, M.A. King, D. Monselesan, B. Legresy, and C. Harig. 2017. The increasing rate of global mean sea-level rise during 1993-2014. Nature Climate Change 7:492-495.
Chudnovsky, A., C. Tang, A. Lyapustin, Y. Wang, J. Schwartz, and P. Koutrakis. 2013. A critical assessment of high-resolution aerosol optical depth retrievals for fine particulate matter predictions. Atmospheric Chemistry and Physics 13:10907-10917.
City and County of San Francisco. 2016. San Francisco Sea Level Rise Action Plan. March. http://sf-planning.org/sea-level-rise-action-plan.
City of New York. 2015. “Mayor de Blasio Releases NPCC 2015 Report, Providing Climate Projections Through 2100 for the First Time.” Office of the Mayor: News. February 17. http://www1.nyc.gov/office-of-the-mayor/news/122-15/mayor-de-blasio-releases-npcc-2015-report-providing-climate-projections-2100-the-first.
City of San Diego. 2005. City of San Diego Climate Protection Action Plan. Environmental Services Department. July. https://www.sandiego.gov/sites/default/files/legacy/environmental-services/sustainable/pdf/action_plan_07_05.pdf.
Clark, J., A. Parsons, T. Zajkowski, and K. Lannom. 2003. Remote sensing imagery support for Burned Area Emergency Response teams on 2003 southern California wildfires. USFS Remote Sensing Applications Center BAER Support Summary.
Clayson, C.A., J.B. Roberts, and A. Bogdanoff. 2017. Seaflux Version 1: A new satellite-based ocean-atmosphere turbulent flux dataset. International Journal of Climatology, submitted.
Crisp, D., H. Pollock, R. Rosenberg, L. Chapsky, R. Lee, F. Oyafuso, C. Frankenberg, et al. 2017. The on-orbit performance of the Orbiting Carbon Observatory-2 (OCO-2) instrument and its radiometrically calibrated products. Atmospheric Measurement Techniques 10(1):59-81.
Curry, J.A., A. Bentamy, M.A. Bouras, D. Bourras, E.F. Bradly, M. Brunke, S. Castro, et al., 2004. Seaflux. Bulletin of the American Meteorological Society 85(3):409-424.
Ebtehaj, A.M., E. Foufoula-Georgiou, G. Lerman, and R.L. Bras. 2015. Compressive Earth observatory: An insight from AIRS/AMSU retrievals. Geophysical Research Letters 42:362-369.
Eldering, A., C.W. O’Dell, P.O. Wennberg, D. Crisp, M.R. Gunson, C. Viatte, C. Avis, et al. 2017. The Orbiting Carbon Observatory-2: First 18 months of science data products. Atmospheric Measurement Techniques 10(2):549-563.
ESA (European Space Agency). 2015. “Earth Observation Portal.” Accessed December 1, 2015. https://directory.eoportal.org/web/eoportal/satellite-missions.
Executive Office of the President. 2010. National Space Policy of the United States of America. Washington, DC. June 28. https://obamawhitehouse.archives.gov/sites/default/files/national_space_policy_6-28-10.pdf.
Fasullo, J.T., C. Boening, F.W. Landerer, and R.S. Nerem. 2013. Australia’s unique influence on global sea level in 2010-2011. Geophysical Research Letters 40(16):4368-4373.
Flechas, J. 2017. “Miami Beach to Begin New $100 Million Flood Prevention Project in Face of Sea Level Rise.” Miami Herald. January 28.
Frankenberg, C., C. O’Dell, J. Berry, L. Guanter, J. Joiner, P. Köhler, R. Pollock, and T.E. Taylor. 2014. Prospects for chlorophyll fluorescence remote sensing from the Orbiting Carbon Observatory-2. Remote Sensing of Environment 147:1-12.
GAO (Government Accountability Office). 2007. Geostationary Operational Environmental Satellites: Further Actions Needed to Effectively Manage Risks. GAO-08-183T. October 23. http://www.gao.gov/products/GAO-08-183T.
GAO. 2010. Polar-Orbiting Environmental Satellites: Agencies Must Act Quickly to Address Risks That Jeopardize the Continuity of Weather and Climate Data. GAO-10-558. http://www.gao.gov/products/GAO-10-558.
Georgieva, E., K. Priestley, B. Dunn, R. Cageao, A. Barki J. Osmundsen, C. Turczynski, and N. Abedin. 2015. “Radiation Budget Instrument (RBI) for JPSS-2,” poster at the Conference on Characterization and Radiometric Calibration for Remote Sensing, https://digitalcommons.usu.edu/calcon/CALCON2015/All2015Content/2/.
Gillespie, T.W., J. Chu, E. Frankenberg, and D. Thomas. 2007. Assessment and prediction of natural hazards from satellite imagery. Progress in Physical Geography 31(5):459-470.
Golaz, J.C., L.W. Horowitz, and H. Levy. 2013. Cloud tuning in a coupled climate model: Impact on 20th century warming. Geophysical Research Letters 40(10):2246.
Gray, J.M., S. Frolking, E.A. Kort, D.K. Ray, C.J. Kucharik, N. Ramankutty, and M.A. Friedl. 2014. Direct human influence on atmospheric CO2 seasonality from increased cropland productivity. Nature 515(7527):398.
Griggs, G., J. Árvai, D. Cayan, R. DeConto, J. Fox, H.A. Fricker, R.E. Kopp, C. Tebaldi, and E.A. Whiteman. 2017. Rising Seas in California: An Update on Sea-Level Rise Science. California Ocean Protection Council Science Advisory Team Working Group, California Ocean Science Trust. April 2017. http://www.opc.ca.gov/webmaster/ftp/pdf/docs/rising-seas-in-california-an-updateon-sea-level-rise-science.pdf.
Han, B., H. Ding, Y. Ma, and W. Gong. 2017 Improving retrieval accuracy for aerosol optical depth by fusion of MODIS and CALIOP data. Tehni ki Vjesnik 24(3):791-800.
Harig, C., and F.J. Simons. 2015. Accelerated West Antarctic ice mass loss continues to outpace East Antarctic gains. Earth and Planetary Science Letters 415:134-141.
Hester, Z. 2016. China and NASA: The challenges to collaboration with a rising space power. Journal of Science Policy and Governance 9(1).
Hilton, F., R. Armante, T. August, C. Barnet, A. Bouchard, C. Camy-Peyret, V. Capelle, et al. 2012. Hyperspectral Earth observation from IASI: Five years of accomplishments. Bulletin of the American Meteorological Society 93:347-370.
Hong, Y., K. Hsu, S. Sorooshian, and X. Gao. 2004. Precipitation estimation from remotely sensed imagery using an artificial neural network cloud classification system. Journal of Applied Meteorology 43:1834-1852.
Hsu, K., X. Gao, S. Sorooshian, and H.V. Gupta. 1997. Precipitation estimation from remotely sensed information using artificial neural networks. Journal of Applied Meteorology 36(9):1176-1190.
Huffman, G.J., R.F. Adler, D.T. Bolvin, G. Gu, E.J. Nelkin, K.P. Bowman, Y. Hong, E.F. Stocker, and D.B. Wolff. 2007. The TRMM Multi-satellite Precipitation Analysis: Quasi-global, multi-year, combined-sensor precipitation estimates at fine scale. Journal of Hydrometeorology 8(1):38-55.
Huffman, G.J., D.T. Bolvin, D. Braithwaite, K. Hsu, R. Joyce, and P. Xie. 2014. “GPM Integrated Multi-Satellite Retrievals for GPM (IMERG) Algorithm Theoretical Basis Document (ATBD).” Version 4.4. PPS. NASA Goddard Space Flight Center, Greenbelt, MD.
IPCC (Intergovernmental Panel on Climate Change). 2013. The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (T.F. Stocker, D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex, and P.M. Midgley, eds.). Cambridge and New York: Cambridge University Press.
Jacobson, M., R.J. Charlson, H. Rodhe, and G.H. Orians. 2000. Earth System Science: From Biogeochemical Cycles to Global Changes. London, UK: Academic Press.
Jason. 2012. Compressive Sensing for DoD Sensor Systems. JSR-12-04. McLean, VA: The MITRE Corporation.
Joyce, R.J., J.E. Janowiak, P.A. Arkin, P. Xie. 2004. CMORPH: A method that produces global precipitation estimates from passive microwave and infrared data at 8 km, hourly resolution. Journal of Climate 5:487-503.
Kavanaugh, M.T., B. Hales, M. Saraceno, Y.H. Spitz, A.E. White, and R.M. Letelier. 2014. Hierarchical and dynamic seascapes: A quantitative framework for scaling pelagic biogeochemistry and ecology. Progress in Oceanography 120:291-304.
Kettunen, P., and M. Laanti. 2008. Combining agile software projects and large-scale organizational agility. Software Process: Improvement and Practice 13:183-193.
Kloog, I., A. Chudnovsky, P. Koutrakis, and J. Schwartz. 2012. Temporal and spatial assessments of minimum air temperature using satellite surface temperature measurements in Massachusetts, USA. Science of the Total Environment 432:85-92.
Kloog, I., A.A. Chudnovsky, A.C. Just, F. Nordio, P. Koutrakis, B.A. Coull, A. Lyapustin, Y. Wang, and J. Schwartz. 2014. A new hybrid spatio-temporal model for estimating daily multi-year PM 2.5 concentrations across northeastern USA using high resolution aerosol optical depth data. Atmospheric Environment 95:581-590.
Kopp, R.E., R.M. Horton, C.M. Little, J.X. Mitrovica, M. Oppenheimer, D.J. Rasmussen, B.H. Strauss, and C. Tebaldi. 2014. Probabilistic 21st and 22nd century sea-level projections at a global network of tide-gauge sites. Earth’s Future 2:383-406.
Kostadinov, T.S., S. Milutinovi, I. Marinov, and A. Cabré. 2016. Carbon-based phytoplankton size classes retrieved via ocean color estimates of the particle size distribution. Ocean Science 12:561-575.
Kruel, S. 2016. The impacts of sea-level rise on tidal flooding in Boston, MA. Journal of Coastal Research 32(6):1302-1309.
L’Ecuyer, T.S., W. Berg, J. Haynes, M. Lebsock, and T. Takemura. 2009. Global observations of aerosol impacts on precipitation occurrence in warm maritime clouds. Journal of Geophysical Research: Atmospheres 114(D9).
L’Ecuyer, T.S., H.K. Beaudoing, M. Rodell, W. Olson, B. Lin, S. Kato, and G. Huffman. 2015. The observed state of the energy budget in the early twenty-first century. Journal of Climate 28(21):8319-8346.
Lee Z., J. Marra, M.J. Perry, and M. Kahru. 2015. Estimating oceanic primary productivity from ocean color remote sensing: A strategic assessment. Journal of Marine Systems 149:50-59.
Liu, J., J.A. Curry, C.A. Clayson, and M.A. Bourassa. 2011. High-resolution satellite surface latent heat fluxes in North Atlantic hurricanes. Monthly Weather Review 139(9):2735-2747.
Liu, Y., and D.J. Diner. 2017. Multi-angle imager for aerosols: A satellite investigation to benefit public health. Public Health Reports 132(1):14-17.
Liu, Y., M. Franklin, R. Kahn, and P. Koutrakis. 2007. Using aerosol optical thickness to predict ground-level PM 2.5 concentrations in the St. Louis area: A comparison between MISR and MODIS. Remote Sensing of Environment 107(1):33-44.
Liu, Y., P. Koutrakis, and R. Kahn. 2007. Estimating fine particulate matter component concentrations and size distributions using satellite-retrieved fractional aerosol optical depth: Part 1—Method development. Journal of the Air and Waste Management Association 57(11):1351-1359.
Lu, Z., D.G. Streets, B. de Foy, L.N Lamsal, B.N. Duncan, and J. Xing. 2015. Emissions of nitrogen oxides from US urban areas: Estimation from Ozone Monitoring Instrument retrievals for 2005-2014. Atmospheric Chemistry and Physics 15:10367-10383.
Lustig, M., D.L. Dononho, J.M Santos, and J.M Pauly. 2008. Compressed sensing MRI. IEEE Signal Processing Magazine 72.
McCarthy, M.J., K.E. Colna, M.M. El-Mezayen, A.E. Laureano-Rosario, P. Méndez-Lázaro, D.B. Otis, et al. 2017. Satellite remote sensing for coastal management: A review of successful applications. Environmental Management 60(2):323-339.
McClain, C.R. 2009. A decade of satellite ocean color observations. Annual Review of Marine Science 1:19-42.
Mechoso, C., R. Wood, R. Weller, C.S. Bretherton, A. Clarke, H. Coe, C. Fairall, J.T. Farrar, G. Feingold, and R. Garreaud. 2014. Ocean-cloud-atmosphere-land interactions in the southeastern Pacific: The VOCALS program. Bulletin of the American Meteorological Society 95:357-375.
Meeker, M. 2017. Internet Trends 2017—Code Conference. Kleiner Perkins. May 31. http://www.kpcb.com/internet-trends.
Menzel, W.P., D.C. Tobin, and H.E. Revercomb. 2016. Infrared Remote Sensing with Meteorological Satellites. Pp. 193-264 in Advances in Atomic, Molecular, and Optical Physics, Volume 65 (E. Arimondo, C.C. Lin, and S.F. Yelin, eds.). London, UK: Academic Press.
Miller, H.M., L. Richardson, S.R. Koontz, J. Loomis, and L. Koontz. 2013. Users, Uses, and Value of Landsat Satellite Imagery—Results from the 2012 Survey of Users. U.S. Geological Survey Open-File Report 2013-1269. http://dx.doi.org/10.3133/ofr20131269.
Mouw, C.B., N.J. Hardman-Mountford, S. Alvain, A. Bracher, R.J.W. Brewin, A. Bricaud, A.M. Ciotti, et al. 2017. A consumer’s guide to satellite remote sensing of multiple phytoplankton groups in the global ocean. Frontiers in Marine Science 4:41.
NASA. 2010. Responding to the Challenge of Climate and Environmental Change: NASA’s Plan for a Climate-Centric Architecture for Earth Observations and Applications from Space. June. http://pace.gsfc.nasa.gov/docs/climate_architecture_final.pdf.
NGAC (National Geospatial Advisory Committee). 2012. “Landsat Advisory Group Statement on Landsat Data Use and Charges.” September 18. https://www.fgdc.gov/ngac/meetings/september-2012/ngac-landsat-cost-recovery-paper-FINAL.pdf.
Nguyen, P., S. Sellars, A. Thorstensen, Y. Tao, H. Ashouri, D. Braithwaite, K. Hsu, and S. Sorooshian. 2014. Satellite track precipitation of Super Typhoon Haiyan. Eos, Transactions American Geophysical Union 95(16):133, 135.
Nguyen, H., N. Cressie, and A. Braverman. 2017 Multivariate spatial data fusion for very large remote sensing datasets. Remote Sensing 9.2:142.
NOAA (National Oceanic and Atmospheric Administration). NOAA NESDIS Independent Review Team Final Report 2017. National Environmental Satellite, Data, and Information Service. https://www.nesdis.noaa.gov/sites/default/files/asset/document/nesdis_irt_report_2017_with_notes.pdf.
NRC (National Research Council). 2000. From Research to Operations in Weather Satellites and Numerical Weather Prediction: Crossing the Valley of Death. Washington, DC: National Academy Press.
NRC. 2005. Earth Science and Applications from Space: Urgent Needs and Opportunities to Serve the Nation. Washington, DC: The National Academies Press.
NRC. 2007. Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond. Washington, DC: The National Academies Press.
NRC. 2008. Ensuring the Climate Record from the NPOESS and GOES-R Spacecraft: Elements of a Strategy to Recover Measurement Capabilities Lost in Program Restructuring. Washington, DC: The National Academies Press.
NRC. 2009. America’s Future in Space: Aligning the Civil Space Program with National Needs. Washington, DC: The National Academies Press.
NRC. 2011. Assessment of Impediments to Interagency Collaboration on Space and Earth Science Missions. Washington, DC: The National Academies Press.
NRC. 2012. Earth Science and Applications from Space: A Midterm Assessment of NASA’s Implementation of the Decadal Survey. Washington, DC: The National Academies Press.
NRC. 2013. Landsat and Beyond: Sustaining and Enhancing the Nation’s Land Imaging Program. Washington, DC: The National Academies Press.
NRC. 2015. Continuity of NASA Earth Observations from Space: A Value Framework. Washington, DC: The National Academies Press.
OECD (Organisation for Economic Co-operation and Development). 2012. OECD Environmental Outlook to 2050: The Consequences of Inaction. Paris, France: OECD Publishing. http://dx.doi.org/10.1787/9789264122246-en.
OIG (Office of Inspector General). NASA. 2016. NASA’s Earth Science Portfolio. Report No. IG-17-003. Washington, DC. https://oig.nasa.gov/audits/reports/FY17/IG-17-003.pdf.
Okamoto, K., T. Iguchi, N. Takahashi, K. Iwanami, and T. Ushio. 2005. “The Global Satellite Mapping of Precipitation (GSMaP) Project.” Pp. 3414-3416 in 2015 IEEE International Geoscience and Remote Sensing Symposium (IGARSS). doi: 10.1109/IGARSS.2005.1526082.
Oppenheimer, M., and R.B. Alley. 2016. How high will the seas rise? Science 354:1375-1377.
Pritchard, H., S.R.M. Ligtenberg, H.A. Fricker, D.G. Vaughan, M.R. Van den Broeke, and L. Padman. 2012. Antarctic ice-sheet loss driven by basal melting of ice shelves. Nature 484(7395):502-505.
Reid, W.V., D. Chen, L. Goldfarb, H. Hackman, Y.T. Lee, K. Mokhele, E. Ostron, K. Raivio, J. Roskstrom, H.J. Shellnhuber, and A. Whyte. 2010. Earth system science for global sustainability: Grand challenges. Science 330(6006):916-917.
Rignot, E., S. Jacobs, J. Mouginot, and B. Scheuchl. 2013. Ice-shelf melting around Antarctica. Science 341(6143):266-270.
Rodell, M., H. Beaudoing, T. L’Ecuyer, W. Olson, J. Famiglietti, P. Houser, R. Adler, et al. 2015. The observed state of the water cycle in the early 21st century. Journal of Climate 28:8289-8318.
Salmon, J.M., M.A. Friedl, S. Frolking, D. Wisser, and E.M. Douglas. 2015. Global rain-fed, irrigated, and paddy croplands: A new high resolution map derived from remote sensing, crop inventories and climate data. International Journal of Applied Earth Observation and Geoinformation 38:321-334.
Scofield, R.A., and R.J. Kuligowski. 2003. Status and outlook of operational satellite precipitation algorithms for extreme precipitation events. Monthly Weather Review 18:1037-1051.
Seattle Office of Sustainability and Environment. 2013. Seattle Climate Action Plan. June. http://www.seattle.gov/Documents/Departments/OSE/2013_CAP_20130612.pdf.
Sellers, P., F. Hall, G. Asrar, D. Strebel, and R. Murphy. 1988. The first ISLSCP field experiment (FIFE). Bulletin of the American Meteorological Society 69:22-27.
Sellers, P., F. Hall, K.J. Ranson, H. Margolis, B. Kelly, D. Baldocchi, G. den Hartog, J. Cihlar, M.G. Ryan, and B. Goodison. 1995. The Boreal Ecosystem-Atmosphere Study (BOREAS): An overview and early results from the 1994 field year. Bulletin of the American Meteorological Society 76:1549-1577.
Siegel, D.A., M.J. Behrenfeld, S. Maritorena, C.R. McClain, D. Antoine, S.W. Bailey, P.S. Bontempi, et al. 2013. Regional to global assessments of phytoplankton dynamics from the SeaWiFS mission. Remote Sensing Environment 135:77-91.
Siegel, D.A., K.O. Buesseler, S.C. Doney, S.F. Sailley, M.J. Behrenfeld, and P.W. Boyd. 2014. Global assessment of ocean carbon export by combining satellite observations and food web models. Global Biogeochemical Cycles 28:181-196.
Simmons, A.J., and A. Hollingsworth. 2002. Some aspects of the improvement in skill of numerical weather prediction. Quarterly Journal of the Royal Meteorological Society 128:647-677.
Simmons, A., J.-L. Fellous, V. Ramaswamy, and K.E. Trenberth. 2016. Observation and integrated Earth-system science: A roadmap for 2016-2025. Advances in Space Research 57:2037-2103.
Smith, S.R., M.A. Bourassa, and D.L. Jackson. 2012. Supporting satellite research with data collected by vessels. Sea Technology Magazine, June, pp. 21-24.
Snider, G., C.L. Weagle, R.V. Martin, A. Van Donkelaar, K. Conrad, D. Cunningham, C. Gordon, et al. 2015. SPARTAN: A global network to evaluate and enhance satellite-based estimates of ground-level particulate matter for global health applications. Atmospheric Measurement Techniques 8:505-521.
Sorooshian, S., K. Hsu, X. Gao, H.V. Gupta, B. Imam, and D. Braithwaite. 2000. Evaluation of PERSIANN System satellite-based estimates of tropical rainfall. Bulletin of the American Meteorological Society 81(9):2035-2046.
Southeast Florida Regional Climate Change Compact. 2015. Unified Sea Level Rise Projection: Southeast Florida. Prepared by the Sea Level Rise Work Group. October. https://www.epa.gov/arc-x/southeast-florida-compact-analyzes-sea-level-rise-risk.
Stephens, G.L., T. L’Ecuyer, R. Forbes, A. Gettelman, C. Golaz, A. Bodas-Salcedo, and K. Suzuki. 2010. On the dreary state of weather and climate models. Geophysical Research 115:D24211.
Stock, C.A., J.G. John, R.R. Rykaczewski et al 2017. Reconciling fisheries catch and ocean productivity. Proceedings of the National Academy of Sciences U.S.A. 114(8):E1441-E1449.
Suzuki, K., T.Y. Nakajima, and G.L. Stephens. 2010. Particle growth and drop collection efficiency of warm clouds as inferred from joint CloudSat and MODIS observations. Journal of the Atmospheric Sciences 67:3019-3032.
Suzuki, K., G.L. Stephens, A. Bodas-Salcedo, M. Wang, J.-C. Golaz, T. Yokohata, and T. Koshiro. 2015. Evaluation of the warm rain formation process in global models with satellite observations. Journal of the Atmospheric Sciences 72(10):3996-4014.
Takahashi, H., K. Suzuki, and G. Stephens. 2017. Land-ocean differences in the warm rain formation process in satellite observations, ground-based observations, and model simulations: Drizzle gap. Quarterly Journal of the Royal Meteorological Society 143(705):1804-1815.
University of Twente. 2016. “ITC’s Database of Satellites and Sensors.” Accessed January 15, 2016. http://www.itc.nl/research/products/sensordb/AllSatellites.aspx.
Vitart, F., C. Ardilouze, A. Bonet, A. Brookshaw, M. Chen, C. Codorean, M. Déqué et al. 2017. The Subseasonal to Seasonal (S2S) Prediction Project Database. Bulletin of the American Meteorological Society 98(1):163-173.
Voigt, S., F. Giulio-Tonolo, J. Lyons, J. Kučera, B. Jones, T. Schneiderhan, G. Platzeck, et al. 2016. Global trends in satellite-based emergency mapping. Science 353(6296):247-252.
Watson, C.S., N.J. White, J.A. Church, M.A. King, R.J. Burgette, and B. Legresy. 2015. Unabated global mean sea-level rise over the satellite altimeter era. Nature Climate Change 5: 565-568.
WMO (World Meteorological Organization). 2016. Sixth WMO Workshop on the Impact of Various Observing Systems on Numerical Weather Prediction (Shanghai, China, 10-13 May 2016): Workshop Report (Y. Sato and L.P. Riishojgaard, eds). Final Report. https://www.wmo.int/pages/prog/www/WIGOS-WIS/reports/WMO-NWP-6_2016_Shanghai_Final-Report.pdf.
Wrona, F.J., M. Johansson, J.M. Culp, A. Jenkins, J. Mård, I.H. Myers-Smith, T.D. Prowse, W.F. Vincent, and P.A. Wookey. 2016. Transitions in Arctic ecosystems: Ecological implications of a changing hydrological regime. Journal of Geophysical Research: Biogeosciences 121:650-674.
Yan, X.-H., T. Boyer, K. Trenberth, T.R. Karl, S.-P. Xie, V. Nieves, K.-K. Tung, and D. Roemmich. 2016. The global warming hiatus: Slowdown or redistribution? Earth’s Future 4: 472-482.
Yueh, S., D. Entekhabi, P. O’Neill, E. Njoku, and J. Entin. 2016. “NASA Soil Moisture Active Passive Mission Status and Science Performance.” Pp. 116-119 in 2016 IEEE International Geoscience and Remote Sensing Symposium (IGARSS). doi: 10.1109/IGARSS.2016.7729020.
Zhan, X., W. Zheng, L. Fang, J. Liu, C. Hain, J. Yin, and M. Ek. 2016. “A Preliminary Assessment of the Impact of SMAP Soil Moisture on Numerical Weather Forecasts from GFS and NUWRF Models.” Pp. 5229-5232 in 2016 IEEE International Geoscience and Remote Sensing Symposium (IGARSS). doi: 10.1109/IGARSS.2016.7730362.
Zhao, B., J.H. Jiang, Y. Gu, D. Diner, J. Worden, K.-N. Liou, H. Su, J. Xing, M. Garay, and L. Huang. 2017. Decadal-scale trends in regional aerosol particle properties and their linkage to emission changes. Environmental Research Letters 12(5): 054021.
Zhou, C., M.D. Zelinka, and S.A. Klein. 2016. Impact of decadal cloud variations on the Earth’s energy budget. Nature Geoscience 9(12):871-874.
Zhu, X., S. Liang, Y. Pan, and X. Zhang. 2011. Agricultural irrigation impacts on land surface characteristics detected from satellite data products in Jilin Province, China. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing 4(3): 721-729.
Zhu, X., D. Liu, and J. Chen. 2012. A new geostatistical approach for filling gaps in Landsat ETM+ SLC-off images. Remote Sensing of Environment 124:49-60.