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Selecting and Prioritizing the Missions P olicymakers and the public are asking Earth scientists new questions about the vulnerabilities of a planet facing population growth, indus- trialization, environmental degradation, climate change, and other serious concerns. Past advances in Earth remote sensing have led to spectacular progress in areas such as weather forecasting; during the next 20 years it is essential that we extend our capabilities in new direc- tions and further integrate our understanding of Earth system components in order to answer such pressing questions as: â¢ Will there be a catastrophic collapse of the Greenland or West Antarctic ice sheets, and if so, how rapidly will this occur? â¢ How will high-latitude forests change because of long-term warming and precipitation changes? â¢ Will droughts become more widespread in semiarid regions such as the western United States, Australia, and sub-Saharan Africa? â¢ How will economic development affect air pollutants and their movement among regions and continents? â¢ Can we better predict the risk of avian flu outbreaks or the potential spread of mosquito-borne viruses as climate evolves? â¢ Will heat waves and tropical cyclones intensify or become more frequent with climate change? â¢ Will the Arctic Ocean become ice-free each summer and, if so, how will this affect ecosystems and people? The committee considered these and many more questions in selecting the 17 missions summarized on pages 10â26. Much of the initial work took place within the seven crosscutting, thematically organized panels (see box on page 6). Six of the panels prioritized observations and candidate missions, using a set of criteria that included affordability, degree of readiness, relationship to other proposed systems, and ability to contribute to more than one theme or discipline and to a long-term record of the Earth system. The seventh panel, which focused on Earth science applications and benefits to society, provided a framework that the other six panels used in evaluating societal benefits of the proposed observations.
Earth Science and Applications from Space Themes areas addressed by the Seven study panels Earth science applications and societal benefits Land-use change, ecosystem dynamics, and biodiversity Weather science and applications Climate variability and change Water resources and the global hydrologic cycle Human health and security Solid-Earth hazards, natural resources, and dynamics Working from the panel reports, the committee further narrowed the list of candidate missions. In doing so, it considered the importance of: â¢ stablishing and maintaining balance in a number of areas (types of measurements, size and E complexity of missions, range of science disciplines, and levels of technological maturity); â¢ Emphasizing cross-benefiting observations that range widely in their spatial and temporal resolution and in their use of different parts of the electromagnetic spectrum; and â¢ Leveraging a broad set of partners, including other agencies, international partners, and the private sector. To develop its plan, the committee exploited both science and measurement synergies among the various priority missions of the individual panels to create a more capable and affordable ob- serving system. For example, the committee recognized that ice sheet change, solid-Earth hazards, and ecosystem health objectives are together well addressed by a combination of radar and lidar in- strumentation. As a result, a pair of missions, flying in the same time frame, was devised to address those three societal issues. In view of the uncertainties attached to cost, technology readiness, and international involve- ment, the committee chose to sequence the recommended missions across three broad periods: 2010â2013, 2013â2016, and 2016â2020. The committee considered the maturity of key tech- nologies as part of the sequencing process. Missions requiring a significant amount of technology development were targeted for the later time frames. Enhanced funding will be needed to bring technology to fruition in time for these later missions. Given the limits on recent and near-future funding for new U.S. observing missions, it is clear that the relative fraction of Earth-sensing satellites launched and managed by other countries will increase over the next few years. The committee took the schedules of major international missions into account when setting the time frames for recommended U.S. missions. The uncertain state of many current U.S. observing systems, and the fiscal uncertainty within key agencies, added to the challenge of developing a strategy for the next decade and beyond. Costs for each mission, in constant 2006 dollars, were estimated in consultation with NASA mission designers, based on known costs for many current and past missions. Final costs will hinge on how each mission is ultimately implemented. For the configurations recommended here, the committee expects that cost estimates should hold to within plus or minus 50 percent for smaller missions and plus or minus 30 percent for larger ones.
Earth Science and Applications from Space To implement the full set of missions, the NASA Earth science budget will have to increase from around $1.5 billion per year in fiscal year 2007 (in constant 2006 dollars) to $2 billion per year between 2008 and 2010, which would reinstate support at the level that existed as recently as 2000. The missions recommended for NOAA can be accomplished with relatively small budget increases, keeping in mind that NOAA budgets are likely to be constrained due to the recent large cost overruns of the National Polar-orbiting Operational Environmental Satellite System (NPOESS) pro- gram (supported jointly by NOAA and the U.S. Department of Defense). Among the many key measurements made by NOAA and NASA missions expected to end over the next few years, the committee identified sev- eral that are essential to sustain into the next decadeâboth to ensure a continuous supply of critical data and to provide a foundation for the observations to be made by recommended new missions. For instance, several instru- ments originally planned but more recently dropped from the NPOESS and Geostation- ary Operational Environmental Satellites (GOES-R) programs should be restored or their measurements obtained by other means. These include instruments to mea- sure the incoming components of radiation from the Sun and the outgoing compo- nents of radiation from Earth (both needed to determine the energy balance of the planet); ocean wind speed and direction; sea surface temperature; and ozone. Without these sensors, gaps may develop in the ob- serving record as soon as 2008. In addition, the committee emphasizes the need to bring selected research instruments to operational status and to foster leadership and in- novation through new opportunities in space-based observing. The committee thus recommends that NOAA increase its investment in transferring research tools and observations to operational use and that NASA create a new line of comparatively low-cost âVentureâ mis- sions (costing from $100 million to $200 million, with new starts every 2 years). Venture missions could range from stand- alone missions with simple, small instruments and spacecraft to more complex instruments launched on partner or shared spacecraft; all would be designed to answer targeted questions.