The IPY Vision Report (NRC, 2004) highlighted the view that the polar environment is a tightly coupled system and that “IPY 2007-2008 is an opportunity to deepen our understanding of the physical, biological, and chemical processes in the polar regions and their global linkages and impacts.” This system perspective embraced by the IPY research community (Overpeck, 2005) differed from the more disciplinary focus of previous IPY/IGY programs (Wilson, 1961). It also required innovations, such as research tools that enabled simultaneous analysis of multiple climate system components; coordinated use of in situ and remote sensing observational instrumentation; access to nontraditional data sources; and a diversity of new and existing computer models. The approach was inherently multidisciplinary and both facilitated and benefited from international collaboration for the establishment, operation, and maintenance of observing networks and other tools and resources.
The following sections present examples of research tools and their use during IPY, with descriptions of new tools and observatories that were made possible by international organizational arrangements. These developments facilitate the collection of data sets that support examination from a system perspective.
EXISTING OBSERVATIONS AND PLATFORMS
The large areal extent of the two polar regions makes observing these environments a significant challenge. The areas covered by the Arctic Basin (~12.2 × 106 km2), Arctic sea ice at maximum extent (~15 × 106 km2), Southern Ocean south of the Polar Front (~35 × 106 km2), and Antarctic continent (13.9 × 106 km2) are each appreciably larger than the contiguous United States of America (~7.8 × 106 km2).
When IPY began, observing stations in these regions had limited space and time coverage. For example, although the longest standard weather record in the U.S. Arctic (in Barrow) dates from 1901, there are vast areas such as the main Arctic Basin and the interior of East Antarctica for which traditional meteorological observations are infrequent or lacking. Therefore, one of the main thrusts of IPY was to establish the capacity to acquire bipolar observational data that could serve as a reference point in long-term examinations of temporal and spatial changes, both in comparison to the earlier IPY and IGY observations and perhaps, more importantly, to those of the future.
Satellite-based observations are an essential component of any program attempting to provide system observations over such large regions. During IPY, data collected from a constellation of satellites (Figure 4.1) contributed to research related to melting or growth of polar ice sheets and of sea ice, elevation changes in sea level, ice-climate feedback loops, cloud heights, aerosol distributions, Earth’s radiation balance and temperature, vegetation canopy heights, and global biomass estimates.
FIGURE 4.1 Overview of National Aeronautics and Space Administration (NASA) Earth Observing satellites in operation during IPY. Many sensors carried on these platforms were supported either in full, or in part, by international partners. SOURCE: NASA.
Satellite development and launch is a lengthy process, typically extending over a period of 5 to over 10 years. Thus, by the time the planning of IPY was completed, it was too late to develop and launch satellite systems with a specific IPY focus. Optimization of deployment of satellite-based remote sensing systems related to any broad-based observational program requires that the general program outline and requirements be established well in advance of the actual initiation of the program and be transmitted to the agencies involved in satellite operations. For example, discussions that ultimately led to the ICESat satellite dated back as far as 1979 (Science and Applications Working Group, 1979) (launch date was January 12, 2003). On the other hand, the occurrence and urgency of the IPY strengthened the voice of the polar research community in achieving a rapid recovery from the failed launch of CryoSat-1 in 2005 with the successful launch of CryoSat-2 in 2009.
Satellite observations of the polar regions face several challenges not encountered in lower latitudes. Foremost among these challenges is the lack of data centered on the poles, which arises because Earth observing satellites rarely pass directly over the poles. Rotation of the satellite can avoid this data gap, but this is rarely done; one exception was the Radarsat-1 satellite, which was rotated once on-orbit to obtain synthetic aperture radar (SAR) images of the entire Antarctic ice sheet. These data provide long-term time series of ice sheet changes.
The long periods of darkness and regions of extensive cloud cover, which preclude observations
FIGURE 4.2 Sample of the “you are there” true-color representation of Antarctica possible with the Landsat Image Mosaic of Antarctica (LIMA) draped on a digital elevation model. The region is near McMurdo Station with the Dry Valleys on the right and Koettlitz Glacier on the left. SOURCE: NASA.
that depend on reflected visible light, such as ocean color, provide additional challenges for high-latitude satellite observations. Frequent and consistent satellite observations in these regions require passive or active microwave systems, which are independent of light and cloud cover. However, current passive satellite observations have coarse spatial resolution (tens of kilometers). Active systems such as SAR and scatterometry provide high-resolution all-weather data and have proven to be excellent tools in studies of ice motion and ice type. SAR observations only date from 1991 (ERS-1) and scatterometric studies of sea ice are even more recent.
The development and operation of satellite programs is expensive, making it doubtful that any one country will be able to afford or even have the technical capabilities necessary for launching the suites of satellites required by increasingly sophisticated observing programs. The number of new U.S. Earth observing satellite missions was reduced in the first decade of this century, which set the stage for less extensive observational capacities just as the pace of change increased. As a result, international coordination is all the more important and will undoubtedly be required to focus existing national or foreign satellite capabilities on specific future IPY-like field projects.
A particularly successful execution of this type of international cooperation by multiple national space agencies was the coordination of satellite observing sensors managed by the IPY Space Task Group (STG). The conceptual birth of this project was a Polar Snapshot from Space, which became the IPY project GIIPSY (Global Inter-agency IPY Polar Snapshot Year). It figured heavily in garnering enthusiasm for IPY throughout the scientific communities and funding agencies by demonstrating the clear benefit of collecting consistent data of both polar regions in a short period of time as a unique observational benchmark. A data collection plan, crafted by GIIPSY from multiple scientist requests into a specific set of data requests, was successfully brokered by the STG with 14 space agencies. 1 Once IPY was under way, GIIPSY-orchestrated data were directly responsible for providing a wide variety of compelling IPY projects with essential data, including pole-to-coast multifrequency measurements of ice-sheet surface velocity, repeat fine-resolution mapping of the entire Southern Ocean sea ice cover, a complete visible and thermal infrared snapshot of circumpolar permafrost, snapshots of lake and river freeze-up and breakup, The impressive success of this effort has resulted in the continuation of the STG and serves as much as an important legacy of IPY as the vast wealth of satellite data that were collected during IPY.
The Landsat Mosaic of Antarctica (LIMA2), an online atlas and digital library of the continent, is an excellent example of the powerful effect of using large, comprehensive satellite data sets in innovative ways
1 Participating International Space Agencies: Agenzia Spaziale Italiana, Canadian Space Agency, China Meteorological Administration, Centre National d’Etudes Spatiales (France), Deutsches Zentrum für Luft-und Raumfahrt, (Germany), European Space Agency, European Organisation for the Exploitation of Meteorological Satellites, Instituto Nacional de Pesquisas Espaciais (Portugal), Japan Aerospace Exploration Agency, NASA, NOAA, Russian Federal Service for Hydrometorology and Environmental Monitoring, WMO, World Climate Research Programme-Climate and Cryopshere.
FIGURE 4.3 Tracks of IceBridge flights during March to May 2009 on which data were collected by the Airborne Topographic Mapper, a laser altimetric instrument. Similar patterns of spatially concentrated flights have been completed annually in both the Arctic and Antarctic in subsequent years. SOURCE: NASA.
during IPY. Documenting changes in the distribution of Emperor penguin rookeries was already mentioned as a significant discovery enabled by LIMA, but the manner in which the mosaic was created set a new standard in the production of such continental-scale mosaics (Figure 4.2). This mosaic was created using over 1,000 ETM+ (Enhanced Thematic Mapper Plus) images at 15-meter spatial resolution, which are produced by an eight-band multispectral scanning radiometer on the Landsat 7 satellite. Previous mosaics at this scale served only as an index to the original data and relied on users to return to single images to perform quantitative analysis. LIMA data are scientifically accurate surface reflectances and thus can be used immediately for scientific inquiry, empowering many more scientific users.
In the face of diminished future observational capability, the IceBridge program represents a novel approach to addressing a gap in satellite observational capability at a critical time and is an important addition to the normal NASA program for satellite-based observations of the polar regions. This 6-year aircraft-borne remote sensing program provides an extensive survey of sea and glacial ice masses in both polar regions and is done in cooperation with Australian, British, Canadian, and French investigators. The data collected from this program provide a focused view of a region (Figure 4.3), as opposed to the broader view obtained from satellites.
Although the primary purpose of the program is to fill in the data collection gap between ICESat, which provided limited data because of power supply problems, and the launch of ICESat-2 estimated for 2016, it contributed directly to IPY and to the longevity of data collection initiated under IPY.
A number of observing networks were established during IPY that attempted to add substantial value to multiple scientific endeavors by combining or extending the data collection capabilities beyond what single countries or projects could either install or sustain. A brief description of some of the different observing networks developed for and utilized as part of IPY follows.
Arctic Observing Networks
In the Arctic, the Sustaining Arctic Observing Networks (SAON) aggregated smaller national observational networks into a broad international coalition. This concept was fostered in the United States as the Arctic Observing Network (AON; a major U.S. government agency IPY initiative, with a majority of the support from the National Science Foundation [NSF]).
FIGURE 4.4 AON, a major initiative during IPY, encompassed physical, biological, and human observations of the land, ocean, and atmosphere. The geographical coverage of U.S. AON projects can be seen in this map. SOURCE: Arctic Research Mapping Application.
Initially designed to support the data needs of the Study of Environmental Arctic Change (SEARCH) program, AON’s multidisciplinary constitution encompassed physical, biological, and human observations (including local/indigenous knowledge) of the land, ocean, and atmosphere. Data products, dissemination, and archiving of AON-collected data are being handled by the Cooperative Arctic Data and Information Service (CADIS3) (see Data Management section later in this chapter). The geographical coverage of U.S. AON projects can be seen in Figure 4.4. The international basis of IPY blended the ongoing observations from the U.S.-only AON program with the active international projects under the SAON program. These international collaborations shared many of the same objectives, but with expanded pan-Arctic coverage. The coordination of SAON is still evolving, and researchers are just beginning to publish results4 with more expected in the coming years.
Separate disciplines within polar science also established broad networks. One example is the integrated Arctic Ocean Observing System (iAOOS), which was formulated by the Ocean Sciences Board and the Climate and Cyrosphere (CliC) Project to explore answers to a number of specific questions concerning the Arctic Ocean and its peripheral seas. The iAOOS framework was designed to collect ocean observations from the seabed to the surface and across both major inflow/outflow pathways between Arctic and sub-Arctic waters as well as a pan-Arctic Ocean transect. As of 2007, over 156 moorings were in place, and these increased to 173 by 2008 (Dickson and Fahrbach, 2011). The regions of interest included the main Arctic Ocean basin; its
4 In particular, several results in Chapter 3 on Marine Ecosystems in a Warming World rely on SAON data.
FIGURE 4.5 The integrated Arctic Ocean Observing System (iAOOS) was designed to collect ocean observations from the seabed to the surface and across both major inflow/outflow pathways between Arctic and sub-Arctic waters as well as a pan-Arctic Ocean transect. This map shows the distribution of all 173 current meter moorings and arrays across the iAOOS domain in 2008. Small numerals in red refer to the number of moorings in an array, where these are too numerous to distinguish individually. SOURCE: Dickson and Fahrbach, 2011.
peripheral seas; the Canadian Archipelago; the Fram, Davis, and Bering Straits; Greenland; and the Russian Arctic. The pattern of moorings deployed during IPY concentrated arrays at four major inflow/outflow regions (Figure 4.5). In addition, some of the data sets were collected by remotely controlled SeaGliders (discussed later in this chapter), which is a new technology that will undoubtedly be used extensively in the future. Extensive advance coordination was needed to successfully collect a spatially extensive data set owing to the fact that these regions included all nations bordering on the Arctic Ocean.
Another aspect of iAOOS was the use of autonomous ice-based observatories. The ice-based observatory concept has developed over the last 30 years, but it was significantly advanced during IPY. These assemblages of colocated instruments returned continuous information about the atmospheric boundary layer and surface radiation budget, the evolving snow and sea ice thickness, temperature and salinity profiles, and temporal stress history and deformation, as well as the upper ocean stratification, water properties (including biologically relevant fields), lateral velocity, and mixedlayer turbulence intensity and associated vertical fluxes (Figure 4.6). Large amounts of data were collected via the ice-based observatories and are still being collected.
Without doubt, new thinking has emerged about the role of the arctic seas in climate. For example, the temperature and salinity of waters flowing into the Norwegian Sea at the Scottish shelf and elsewhere along the Kola Peninsula in the Kara Sea are the warmest observed in over 100 years (Dmitrenko et al., 2008; Holliday et al., 2007; Polyakov et al., 2007). New modeling of the flow by Karcher et al. (2007) show that the this warm Atlantic water layer may have less impact on sea ice as it circulates around the Arctic Basin. Instead it may have more influence on the density contrast and height of this water mass where it exists over the Denmark Strait overflow, thus influencing the thermohaline conveyor into the future. Continued monitoring of this evolving system speaks to the legacy this observing system will have to improving our understanding of the sensitivity of the northern seas to climate change.
The overall goal was to deploy observing sites across the Arctic during IPY with the intent that a subset of the sites would remain in operation after IPY. The SAON process built upon the scientific community’s experience in the Arctic and clearly facilitated deployment of the various IPY Arctic observing programs. By improving international coordination and planning, SAON helped to provide better coverage and perhaps even improved cost-effectiveness. One important goal was to aid in developing sustained support for such networks beyond IPY because long-term support for monitoring programs has invariably proven to be difficult. It is hoped that the SAON program will contribute to the temporal extension of this data set, thereby ensuring an important contribution to climate change research.
An important new data product, the Sea Ice for Walrus Outlook (SIWO), emerged from these observing networks, and has had a direct and immediate
FIGURE 4.6 The concept of the autonomous ice-based observatory has developed over the last 30 years, but it was significantly advanced during IPY. Shown here is a schematic for an icetethered profiler (ITP). The ITP system consists of a small surface capsule that sits atop an ice flow and supports a plastic-jacketed wire rope tether that extends through the ice and down into the ocean, ending with a weight (intended to keep the wire vertical). A cylindrical underwater instrument (in shape and size much like an Argo float) mounts on this tether and cycles vertically along it, carrying oceanographic sensors through the water column. Water property data are telemetered from the ITP to shore in near-real time. SOURCE: Richard Krishfield, Woods Hole Oceanographic Institution.
impact on Arctic residents. As a key supporter of the U.S. AON, SEARCH5 (Study of Environmental Arctic Change), an interagency activity to understand the broad, interrelated changes occurring in the Arctic, brought together a diverse group of specialists to share and discuss sea ice distribution predictions for the anticipated sea ice minimum and facilitate the exchange of approaches and the successes (or failures) of the resulting predictions so that forecasting skill could be improved. The forecasts were then provided to native hunting groups in the form of the SIWO. Ultimately, observations made during hunts were provided to the forecasting group, with the expectation that this would contribute to improved 10-day weather and ice forecasts provided to communities located along the coasts of the Beaufort, Chukchi, and Bering Seas.
Antarctic Observing Networks
In the Southern Hemisphere, planning for a network of ocean observations began during IPY. This project, the Southern Ocean Observing System (SOOS), is designed to provide multidisciplinary observations from one of the least well-observed parts of the ocean. The region is remote, and its climate and associated sea state are sufficiently formidable to limit observations. The goal of SOOS is to utilize the unprecedented level of cooperation available under IPY to gain a synoptic snapshot of the state of the Southern Ocean, using both established tools and new technology such as cryospheric satellites, autonomous profiling floats, and miniaturized sensors deployable on marine mammals. When it is implemented, SOOS is designed to provide the longterm measurements required to improve understanding of climate change and variability, biogeochemical cycles, and the coupling between climate and marine ecosystems. The full SOOS plan describes the combination of sustained observations needed to address the key science challenges identified for the Southern Ocean (Rintoul et al., 2011). SOOS consists of a series of elements that allow these science challenges to be addressed.
The primary SOOS elements are repeat hydrography, enhanced Southern Ocean Argo system, underway sampling from ships, time-series stations and monitoring of key passages, animal-borne sensors, sea ice
observations and enhanced ice drifter arrays, observation of ocean circulation under ice and ice shelves, enhanced meteorological observations, remote sensing, and inclusion of observations of lower trophic level processes and ecological monitoring. The general location of proposed repeat hydrography and Argo float observations (Figure 4.7) illustrate the region covered by the SOOS. The general decrease in coverage with increasing latitude is associated with increasing remoteness as well as with the presence of sea ice. An important aspect of the SOOS is emphasis on data archaeology, management, archiving, and access, as described in the SOOS science plan (Rintoul et al., 2011). This is considered critical to understanding any new measurements.
As initially planned, SOOS intends to make use of a full suite of remote sensing observations including radar and laser altimetry, scatterometry, SAR, ocean color, and passive microwave observations. Observations from ICESat were sufficient to verify the use of laser altimetry in obtaining estimates of both snow and sea ice thickness in the Southern Ocean; information that has been largely lacking to date.
Each element of the SOOS observing tools exists in some form and is ready for implementation now. The international effort in coordinating research programs in the Southern Ocean during IPY6 demonstrated the readiness and feasibility of a comprehensive, integrated system of Southern Ocean observations. In 10 years, the SOOS will likely have expanded to rely more heavily on autonomous sampling that includes floats, gliders, satellites, moorings, and animal-borne sensors. A complete discussion and overview of the SOOS strategy is given in Rintoul et al. (2011).
Bipolar Observing Systems
The Polar Earth Observing Network (POLENET7) is a terrestrial, bipolar example of a new observational network established during IPY. Prior to IPY there were very few continuous GPS receivers and seismic sensors in either the Antarctic or Greenland. The establishment of POLENET provided a polar observing system for geodesy and seismology in both regions (Figure 4.8) at a greater density than found at some other remote regions of the world. For example, about 50 autonomous seismic stations operated continuously in the Antarctic interior during IPY as contrasted with one (South Pole) prior to IPY. The continued operation of many of these stations is an important legacy of IPY. Data from these stations will contribute important insights into glacial rebound in both areas, internal processes within the ice, and rates of ice loss. POLENET data in combination with data from the Gravity Recovery and Climate Experiment (GRACE) satellite is leading to improved ice mass balance estimates to determine how the world’s largest ice sheets in Greenland and Antarctica are changing (Bromwich and Nicolas, 2010; Wu et al., 2010). Longer GPS time series will also lead to better estimates of the history of ice mass fluctuations since the last glacial maximum.
Sea Ice Observing Networks
Extensive observational networks carry an additional benefit that unforeseen shortfalls in one can sometimes be minimized by shifting some observational tasks to another network. This was demonstrated by the interactions between the U.S. Sea Ice Mass Balance in the Antarctica (SIMBA) and the Australian Sea Ice Physics and Ecosystem eXperiment (SIPEX) programs. The SIMBA program was an international interdisciplinary study focused on sea ice processes integrated with oceanographic, meteorological, and marine mammal components. During 2007, while operating in the Amundsen Sea, a ship fire resulted in the loss of 3 weeks of a planned 2-month field season. However, this loss of data was avoided by transferring some aspects of the SIMBA program to the SIPEX program operating on the other side of the continent. It also was possible to coordinate these changes with the NASA ICESat laser altimeter mission. The resulting satellite-based data set, combined with concurrent field observations, has helped refine algorithms for converting sea ice elevations into more accurate sea ice thickness. These results will contribute to the first analysis of Antarctic sea ice thickness distributions and change. Without previous coordination through IPY, such last-minute changes would have been more difficult to implement.
The experiences in setting up many of the IPY observing networks provide lessons for planners of
FIGURE 4.7 The Southern Ocean Observing System (SOOS) is designed to provide multidisciplinary observations from one of the least well-observed parts of the ocean. Two key components of SOOS are shown here: repeat hydrographic lines and Argo floats. Top panel: The locations of the proposed SOOS hydrographic lines. Bottom panel: The locations of Southern Ocean Argo float observations made during IPY; the general decrease in coverage closer to the Antarctic continent is associated with increasing remoteness as well as with the presence of sea ice. SOURCE: Rintoul et al., 2011.
related future programs. For example, sensor deployment was a challenge. This will undoubtedly continue to be the case in the future even though environmental conditions may be quite different. If current climate trends continue, areas of multiyear ice, favored as deployment sites, will be both smaller and increasingly remote. Furthermore, although the increase in the icefree areas during the late summer will favor the use of ships to deploy buoys, subsequent ice formation during the winter may severely limit the usefulness of such buoys. Also, providing a data set that was adequate for all possible users was particularly difficult, for example, the biogeochemical aspects of polar observational programs could and should have been expanded. Thus, it is important to formulate measurement needs well in advance of the actual program so that the collection systems can be optimized for the specific research needs. Involvement of early career scientists in programs such as iAOOS that are expected to last for decades is critical—it may advance the careers of the younger scientists, but it will certainly contribute to the desired longevity of the observing program, which may well exceed the temporal involvement of the initial developers.
FIGURE 4.8 Maps showing POLENET networks before and after IPY. Continuously recording GPS and seismic stations are shown prior to IPY (a, b) and deployed during the extended IPY period from 2006 to early 2010 (c, d). SOURCE: POLENET database; maps drafted by M. Berg and S. Konfal.
Icebreaker Support Capabilities
Performing scientific research in the polar regions often requires research vessels capable of operating in fully and partially ice-covered seas. As such, ships capable of breaking through ice are required for operations in both the Arctic and Antarctic. Icebreakers are required for scientific and supply missions in the Arctic, including operations in the Bering, Chukchi, and Beaufort Seas. In the Antarctic, heavy ice-breaking capability is required to clear a path through the thick continuous first-year (FY) sea ice in McMurdo Sound to allow cargo ships to carry out the annual resupply of the U.S. and New Zealand bases at McMurdo. This resupply is essential to the operation of these stations and the U.S. station located at the South Pole.
The current status of U.S. ships with icebreaking capabilities is uncertain. The USCG icebreaker Polar Sea is scheduled to be decommissioned in 2011. Its sister ship, the Polar Star, is now over 30 years old and has been undergoing repairs designed to extend its service life for 5 to 7 years. The two ships are unique in that they have the capability of increasing their horsepower from 16,000 to 60,000 by activating an additional gas turbine system, which allows them to complete the McMurdo break-in.
The two other U.S.-owned ice-capable vessels in current use are the USCG Healy and the NSF chartered RVIB Nathaniel B. Palmer. The Healy, although the largest ship in the history of the Coast Guard, has proven to have great difficulty maneuvering in thick continuous FY ice; therefore its operations are currently limited to the Arctic where it has proven to be an effective asset for operations in the Bering, Chukchi, and Beaufort Seas. The Palmer, operated on contract for the NSF, was designed for Antarctic operations and has proven to be capable of operations in FY Antarctic pack ice, but its ice-breaking capabilities are less than required for the annual break-in for the McMurdo Sound. The Palmer entered service in 1992 and has been in essentially continuous operation for 19 years. As a result, it will undoubtedly require enhanced maintenance during its remaining operational lifetime.
During IPY, NSF was able to make arrangements to have the Swedish icebreaker Oden break out the channel to McMurdo Sound. In the past, Russian icebreakers have also been chartered to carry out this essential task and it has just been announced that during the coming 2011-2012 austral summer another Russian icebreaker, the Vladimir Ignatyuk, has been contracted for this task. Such arrangements, if possible, are desirable in that they, by leveraging other country’s marine investments, provide both nations with a return that is greater than would be obtained by working alone. The difficulty is that it is impossible to guarantee that such arrangements can be made every year. If a suitable replacement cannot be found, U.S. and New Zealand operations in the McMurdo area and in East Antarctica in general will have to be severely curtailed, if not completely cancelled.
In the Arctic, the Healy will continue to operate, and the Sikuliaq, with less icebreaking capabilities than those of the Healy, is under construction. At 261 feet and 5,750 HP, the Sikuliaq’s winter in-ice operations will probably be limited to the Bering Sea, and its summer operational area will likely include both the Chukchi and Beaufort Seas. It should prove to be an effective operational platform but it is not designed for deep extended operations into the Arctic Basin. The Healy may prove capable of winter operations in the main Arctic Basin, but confidence in this capability awaits further field tests.
In the Antarctic, as the Palmer approaches the end of its operational life, the U.S. Antarctic Research Program will essentially be without icebreaking capability. In particular, it will lack the capability of operating in the Southern Ocean during the winter and of breaking out the U.S. Base at McMurdo Sound during the summer, an operation essential to base resupply. If U.S. operations are to continue in the Antarctic, the lengthy design and construction time required to produce an operational icebreaker requires that the decision to initiate development of a replacement ship should be made soon. Inherent in the design should be two primary capabilities. This replacement vessel needs to be capable of operating in thick, continuous FY ice and should have a design that supports multidisciplinary research.
NEW OBSERVATIONS FROM SPECIFIC TOOLS
Several recently developed research tools were used during IPY. Given the long lead time required to
plan, secure funding, and develop new tools, work on all of these research tools began well before IPY and in some cases even before IPY planning began. While IPY may not have directly benefited the initial stages of tool development, the existence of a large, multidisciplinary, international project such as IPY provided the opportunity to deploy and test new tools as parts of large observing networks. Some examples of such innovative tools that provided a new perspective on the polar system are highlighted below.
Over the past 25 years, much has been learned about the spatial and temporal variability of the physical, chemical, and biological distributions and processes in the ocean, and it is now known that changes in oceanic processes occur over a variety of space and time scales. In high-latitude systems, seasonal cycles in irradiance, wind fields, and sea ice concentration and extent are important in determining ocean stratification, upper ocean heating, and biological productivity. However, short-term physical variations such as eventscale mixing also play a dominant role in controlling the magnitude of these processes as well as their timing and duration. These events are likely quite common in high-latitude systems, but are rarely sampled, and as such their importance to seasonal and annual cycles remains poorly quantified (see the section on Sea Ice in Chapter 3).
One reason such events are rarely sampled is that traditional ship-based sampling does not often resolve processes on either the mesoscale (i.e., eddies, fronts, and currents), or seasonal time scales. To adequately resolve these sampling needs, new technologies were needed. Gliders, autonomous vehicles that can sample a limited suite of variables for long periods of time, represented one such new technology. Gliders are capable of extended missions (several months), are durable, and carry sensors that provide coincident measurements of temperature, salinity, optics, fluorescence, and transmissometry, which provide high-resolution space and time representations of environmental and biological conditions.
During IPY, SeaGliders (Figure 4.9), developed by U.S. scientists, were deployed off western Greenland. These gliders provided 6-month time series of freshwater export from the Arctic Ocean through the Canadian Arctic Archipelago and Davis Strait into the Labrador Sea. The amount of freshwater entering the Labrador Sea determines the formation of dense water in this region. Thus, understanding the variability in freshwater supply is critical to understanding the effect of climate change on the larger-scale ocean thermohaline circulation. The SeaGliders were one of the many instruments included in the Arctic Observing Network (AON). The SeaGlider represented an advance over other autonomous underwater vehicles in that it does not use propulsion to move through the water, can operate on its own for several months, and can operate effectively in ice-covered regions. Unlike ARGO floats, it can maneuver in vertical and horizontal space. At specified intervals it sends data and its GPS position via the iridium satellite to a computer base station, allowing almost real-time analysis of the data. The glider can then receive new instructions from the operator at the base station about what to target next (position), how deep it should go, and its data sampling frequency.
IPY showed that SeaGliders are viable tools for measuring remote regions at space and time scales that are relevant to the oceanographic processes that are of concern for climate change. Subsequent to IPY, SeaGliders had been deployed successfully in other highlatitude regions, such as the Ross Sea. This instrumentation is rapidly gaining acceptance and is becoming part of multidisciplinary oceanographic programs.
Animal-Borne Ocean Sensors
The use of animal-borne conductivity-temperature-depth satellite relay data loggers (CTD-SRDL) tags to study habitat and behavior was the core theme of the IPY MEOP (Marine Mammals as Explorers of the Ocean Pole to Pole) program. This international effort deployed tags in large numbers on grey and hooded seals in the Canadian and Norwegian Arctic and on crabeater, elephant, and Weddell seals in the Southern Ocean (Figure 3.13). The deployment of 85 CTD-SRDLs on southern elephant seals as part of the international Southern Elephant Seals as Oceanographic Sensors (SEAOS) provided a circumpolar assessment of the behavior of southern elephant seals as well as a synoptic view of the oceanography of the Southern Ocean (Biuw et al., 2007).
Satellite-linked dive recorders that sample the temperature and/or salinity while simultaneously recording information on the diving patterns of the seals (Biuw et al., 2007) offer a significant advantage over remotely sensed data in that they acquire oceanographic-quality data at a scale and resolution that matches the animals’ behavior. An equally important advantage is that these tags provide oceanographic data that can contribute to a better understanding of physical oceanography, especially in areas where traditional shipboard and Argo float coverage is limited or absent, such as the Arctic and Southern Oceans.
In the Southern Ocean, the 2 years of IPY-MEOP sensor deployments resulted in 68,000 CTD profiles collected by 166 seals. These data were from mostly data-sparse regions, and a large proportion was from high-latitude regions in winter in areas with 80 percent or more sea ice coverage. The MEOP program provided comprehensive, synoptic coverage that allowed investigation of factors determining habitat selection and use by important polar marine mammal species. The combination of oceanography and marine mammal ecology in MEOP has significantly advanced understanding of how top predators use their environment as well as providing high-resolution hydrographic measurements that can be used to advance understanding of climate processes (e.g., Costa et al., 2008). The IPY effort provided the large-scale verification of the validity of “animals as oceanographers.”
Unmanned Aerial Systems
Early deployment of Unmanned Aerial Systems (UAS) in polar regions began in the late 1990s with flights conducted from Barrow, Alaska. using Aerosonde UAS. The deployment and use of UAS for polar scientific research expanded during IPY through projects such as the U.S.-Norway Traverse project,8 the Center for Remote Sensing of Ice Sheets (CReSIS9), and the NASA-funded Characterization of Arctic Sea Ice Experiment (CASIE), which took place on Svalbard in July 2009. This project used the NASA Sensor Integrated Environmental Remote Research Aircraft (SIERRA) UAS (Figure 4.10) to observe sea ice roughness and sea ice breakup in high northern latitudes.
Similar to SeaGliders, UAS provide a tool that allows for repeat monitoring of atmospheric and surface state in remote or difficult-to-reach locations and provide observations on spatial and temporal scales that allows for investigation of mesoscale features not often observed with other observing systems. Deployment of UAS in the polar regions faces difficulties because of the harsh climatic conditions but avoids logistical difficulties associated with flight clearances needed in more populous mid-latitude locations.
Automatic Weather Stations
The development and deployment of reliable automatic weather stations (AWS), starting in the early 1980s, helped fill significant gaps in surface weather observations in the polar regions. Extensive AWS networks in the Antarctic (Figure 4.11) and Greenland were in place during IPY. Observations from more than 50 AWS systems are used for operational weather forecasting and thus contribute to many field-based polar research activities by facilitating more accurate forecasts. The data from these networks are readily available10 and are used for a wide range of research including atmospheric science and glaciology. The Antarctic continent AWS network is maintained through a 12-nation international effort.
Climate change over the last century has been dramatic and well documented (IPCC, 2007b), but is best evaluated in the context of natural climate variability.
While changes of the last few decades can be weighed in the short term against instrumental and historical data and observations, a better understanding of the character and pacing of natural Earth system variability can only be assessed through paleoclimate studies. Long continuous geologic records contained in ice cores and sediment cores from both marine and lacustrine depositional systems at the poles provide information about natural variability on a variety of time scales. The data from these cores suggest forcing mechanisms and feedbacks at work in global and regional systems. Modeling linked with the geologic record provides
FIGURE 4.10 NASA SIERRA UAS on the runway at Ny Alesund, Svalbard. SOURCE: Julie Brigham-Grette, University of Massachusetts, Amherst.
further information about the sensitivity of regional systems to change caused by human activities.
IPY provided the impetus for a number of international programs and initiatives aimed at recovering exceptionally long, high-resolution geologic records of change in the high latitudes (see Chapter 3 on Discoveries). Because of the exceptional logistical and technical challenges in obtaining these records, new instrumentation and geological drilling systems were designed for the benefit of the polar science community. These systems provide a benchmark for IPY that celebrates collaborations as well as innovation, as illustrated by the following examples.
Drilling successfully at Lake El’gygytgyn (Lake E) in remote northeastern Russia represented a massive logistical and political undertaking (Melles et al., 2011; Figure 4.12). Multiple shipping containers originating at various institutions around the world were transported by ship, rail, truck, and eventually bulldozer. Drilling platform preparation required that the lake ice be artificially thickened to about 2.3 m to support the 100-ton weight of safe operations. Cores were taken using a newly designed hydraulic/rotary system consisting of a diamond coring rig positioned on a mobile platform that was weather-protected by insulated walls and a custom made tent atop a 20-m-high derrick. The system was permanently imported into Russia, where it is now available as a research tool for scientific drilling projects at no cost to the science community until 2014. (Results from this project are described in Chapter 3 in the section on Evidence of Past Climate Change over Geologic Time Scales).
In Antarctica, the new multinational Antarctic Drilling Program (ANDRILL) was launched on the McMurdo Ice Shelf (MIS) in austral summer of 2006 to 2007 by overcoming similar logistic challenges. Using a custom-built drilling system consisting of a diamond drill rig and jack-up platform, the first ANDRILL drilling system operated effectively atop an 85-m-thick portion of the ice shelf that moved laterally and was subject to tides and poorly studied subshelf currents (Figure 4.13). The MIS project successfully recovered 1,285 m of sediment, documenting for the first time the complex interplay among the WAIS, EAIS, and the Southern Ocean (Naish et al., 2009).
Refined technology and geological drilling techniques in both polar regions allowed for the recovery of these unparalleled records, which will catapult the
understanding of high-latitude climate evolution over millions of years.
In parallel with geologic drilling, ice core drilling for paleoenvironmental records (Figure 4.14) also made a number of milestones for IPY. The ongoing recovery of a unique 100,000+-year high-temporal resolution record from the interior of West Antarctica (the first attempted there since the Byrd core during IGY) required the development of the DISC (Deep Ice Sheet Coring) Drill by the U.S. Ice Drilling Design and Operations (IDDO) group at the University of Wisconsin, Madison, a drill with unprecedented ability to drill diagonally from selected depths deep in the ice sheet to retrieve additional, replicate ice cores from scientifically interesting depths (Johnson et al., 2007; Mason et al., 2007; Mortensen et al., 2007; Shturmakov et al., 2007). Moreover, the project led to the development of a new field-based system to take multitrack conductivity measurements of the ice cores,11 which allows scientists to focus on specific core sections, maximizing the scientific information per unit cost. The WAIS Divide project also led to the development of ultramodern laboratory equipment for the continuous stable isotope analysis (oxygen and hydrogen) of recovered ice (Gupta et al., 2009) and carbon dioxide measurements of the “fossil air” enclosed in compressed air bubbles in the ice.
FIGURE 4.11 John Cassano working on an automatic weather station. AWS networks in place during IPY helped fill gaps in surface weather observations. SOURCE: John Cassano, University of Colorado Boulder.
These new technologies were born of longstanding international and science-industry collaborations. Ice coring science had its origins in the IGY era, when the very first ice core was drilled in Greenland by the U.S. Army Cold Regions Research and Engineering Lab. Even though the science and technology are relatively young, international sharing of drill designs and engineering expertise is a hallmark of the ice coring community (Langway, 2008). The International Partnerships for Ice Coring Science,12 one of the IPY legacy organizations, has a group of international drilling engineers who periodically meet to share knowledge and experience about ice core drilling.
MODELS AND REANALYSES
Leading up to and during IPY, polar regional modeling began to focus on system modeling. A series of international workshops from 2007 through 2009 culminated in the publication of A Science Plan for Regional Arctic System Modeling (Roberts et al., 2010) that highlighted the needs for regional Arctic system modeling (ASM) (Figure 4.15). Another focus of polar modeling during IPY was the development of the Arctic System Reanalysis (ASR) (Bromwich et al., 2010). Regional models for the polar regions, including Polar WRF,13 have seen increased development in the years since IPY.
Both ASM and ASR activities provided an opportunity for synergies between observational and modeling communities. The polar system focus of these modeling efforts aligns closely with the system focus of IPY. Observations collected as part of IPY provide validation for these modeling efforts and in the case
11 Kendrick Taylor, Desert Research Institute, personal communication, 2011.
FIGURE 4.12 The U.S.-Russia-German-Austrian Lake El’gygytgyn Scientific Drilling program recovered the first continuous record of past climate change reaching back to 3.6 million years. Images show the field site and the Lake El’gygytgyn Science Party. Lower left map shows the location of the field site. SOURCES: Lake El’gygytgyn Science Party; map: Brigham-Grette et al., 2011.
FIGURE 4.13 Schematic of the ANDRILL-MIS drill core. SOURCES: left, Chicago Tribune; right: ANDRILL Science Management Office, http://www.andrill.org.
of the ASR provided data to constrain the reanalysis. Results from modeling efforts such as this can highlight regions of interest for future observational efforts and can represent in a physically consistent way processes acting on small spatial and temporal scales which until recently have been poorly sampled.
Overall, IPY facilitated closer integration between the observational and modeling communities. Data assimilative models provided inputs used to guide observation and deployment activities and these in turn provided data for the models. This integration represented a positive interaction and as such provides an important legacy from IPY.
FIGURE 4.14 A 1-m-long section of ice core from the West Antarctic Ice Sheet Divide Ice Core; section contains a dark ash layer. SOURCE: Heidi Roop.
FIGURE 4.15 Evolution of regional arctic models. Geophysical ocean-sea ice-atmosphere-terrestrial components have progressively been coupled during the past two decades, while other components have been studied as stand-alone systems. The proposed Arctic System Modeling program will bring a greater understanding of interconnectivity within the Arctic by fostering coupling of biogeochemistry and human dimensions components. SOURCE: Roberts et al., 2010.
The IPY framework report underscored the central role of data by stating “In fifty years time the data resulting from IPY 2007-2008 may be seen as the most important single outcome of the programme” (Rapley and Bell, 2004). Rapid changes in the polar regions make the need to share data more acute because the knowledge being urgently sought to inform decisions is well beyond the means of single investigators, projects, or even single countries. While no data management policy was put in place before IPY project proposals were submitted to the Joint Committee, the Joint Committee later stressed the importance of data sharing and management by instituting a data policy for IPY that emphasized the need to make IPY data, including operational data delivered in real time, available “fully, freely, openly, and on the shortest feasible time scale.” An emphasis on data availability, sharing, and thus management, could have placed IPY on the forefront of efforts to make fundamental advances in this area. However, strategic differences in Arctic and Antarctic data management and the conduct of science investigation within new interdisciplinary structures all challenged data management during IPY. There were no internationally coordinated IPY planning efforts to engage funding sources for planning data archiving, which created an additional funding problem for post-IPY international archiving. Moreover, during the buildup to IPY, the International Council for Science’s (ICSU’s) assessment of the world data centers (many of which were established during the IGY) questioned their viability and collaboration, recommending a major overhaul of ICSU data structures (ICSU, 2004). Thus, ICSU viewed IPY as an opportunity to make critically needed advances in data management.
IPY’s scientific success depended on handling data in ways that enabled researchers to access and use various data sources and in novel ways. The IPY Joint Committee addressed the needs of improved data management by forming a Data Policy and Management Subcommittee14 in late 2005 whose task included the generation of an IPY Data Policy and Strategy. This policy and strategy expressed the importance of data sharing and publication, interoperability across systems through the establishments and adherence to data standards, sustainable preservation and stewardship of diverse data, and coordinated governance to ensure access for all researchers. All IPY projects pledged to honor this policy—a remarkably universal expression of recognition of the important role data played in current and future polar research. This subcommittee also defined an IPY metadata profile consistent with what was being used at several polar data centers and the Global Change Master Directory (GCMD). It also requested national IPY organizations to name a data coordinator responsible for promoting the IPY data standards in their respective countries. To date, 16 countries have identified a data coordinator; in the United States this responsibility is with the National Snow and Ice Data Center (NSIDC).
As a result of IPY, several data centers have established pilot projects to exchange metadata records using the IPY profile and the Open Archives Initiative Protocol for Metadata Harvesting (OAIPMH). Metadata from centers in Canada, Norway, Sweden, the United Kingdom, and the United States are directly provided to the GCMD. With support from the NSF, an IPY Data and Information System (IPYDIS) was established in collaboration with the Electronic Geophysical Year (eGY15). The eGY was an independent effort focused on making past, present and future geophysical data rapidly, conveniently and openly available. It was supported internationally by the International Association of Geomagnetism and Aeronomy and the International Union of Geodesy and Geophysics, while US-based support was provided by NASA, NSF, the U.S. Geological Survey, and the Laboratory for Atmospheric and Space Physics, University of Colorado, with in-kind contributions from the American Geophysical Union and the National Center for Atmospheric Research.
IPYDIS16 established a global partnership of data centers, archives, and networks to ensure proper stewardship of IPY and related data. The substantial U.S. funding support of IPYDIS demonstrates the U.S. commitment to sound data management for internationally collaborative science now and into the future. NSIDC coordinated IPYDIS. It was guided by the IPY policy set by the IPY Data Policy and Management Subcommittee and requested updated data-related information from all IPY projects as those projects evolved. The website17 has instructions to guide researchers submitting metadata to either nationally designated IPY data centers or to the more general GCMD-IPY portal where data are organized into14 disciplinary categories.
IPYDIS also guided users interested in accessing data to specific sites either with direct links or through a prototype search interface called Discovery, Access, and Delivery of Data for IPY (DADDI18). DADDI is presently limited to Arctic coastal data. Under the definition of IPY data established by the IPY Data Subcommittee, 1,400 data sets resulting from IPY have been catalogued in the GCMD (Parsons et al., 2011). Also part of IPYDIS, the International Polar Year Publications Database (IPYPD) was created by the Arctic Science and Technology Information System (ASTIS), the Cold Regions Bibliography Project (CRBP), the Scott Polar Research Institute (SPRI) Library, the Discovery and Access of Historic Literature of the IPYs (DAHLI) project, and the National Information Services Corporation (NISC). It is intended to serve as a database for all publications related to IPY.
In addition to the more general repository effort of IPYDIS, many large IPY projects constructed their own data portals, for example, the Antarctic Drilling Project, the Arctic Observing Network, the Circumpolar Biodiversity Monitoring Programme, the Polar Earth Observing Network, and the Scientific Committee on Antarctic Research Marine Biodiversity Information Network. These additional portals provide access to data not yet available through GCMD, but do demonstrate timely release of data. Other data collected
during IPY by sensors designed and operated with a mission larger than polar-only were naturally added to existing data repositories already designed specifically for those sensors. An example of this category is the wealth of satellite data of the polar regions orchestrated by the IPY Space Task Group that was established for the purpose of coordinating space agency planning, processing, and archiving of the IPY Earth Observation legacy data set. Other sources of data include repositories for polar materials and samples such as the U.S. National Ice Core Laboratory,19 the U.S. Polar Rock Repository,20 the Antarctic Marine Geology Research Facility,21 and the U.S. National Lacustrine Core Facility.22 The collections are available for a wide range of scientific research including current and future studies.
The great diversity of IPY data resulted in some barriers to its use, some causes of which included data unfamiliar to scientists outside the originating discipline, data that did not fit into the organizing structure of the data center, or the absence of tools either to work with data or to even locate relevant data. In some cases these barriers were overcome by the investigators themselves; for example, for the IPY project “Antarctic Snow Accumulation and Ice Discharge (ASAID),” customized software code as well as formal documentation describing its use was supplied to NSIDC. Often, the data center is expected to develop and improve tools so that investigators submitting data (or metadata) find it easy to describe and transfer their data and investigators seeking data can efficiently search for relevant data sets. No grand solutions were achieved during IPY, but the net result of IPY’s focus on data, data sharing, and data management prompted many constructive steps by data centers and investigators alike that have improved data accessibility. Continued efforts in this arena are essential.
Lessons and Legacies in Data Management
The IPY Joint Committee report stated that “the IPY policy of general openness built from existing policies appears to be an initial success” (Parsons et al., 2011). The principle that as much data as possible be fully available in the public domain was adhered to by many and continues to enable discovery-driven research. However, the breadth of IPY social science projects highlighted that when human subjects are involved, other considerations related to data description and availability need to be considered, lest the effectiveness or accuracy of the research be compromised. In social science, trust needs to precede data acquisition; the building of relationships with local residents depends on how collected information will be used and distributed. This is not new to social scientists, but less familiar to physical scientists who, through IPY, sought to bridge the gap between social and physical sciences. On the other hand, the integration of physical science research goals into projects that included local residents often provided a demonstrable and tangible benefit to the residents, building trust and reinforcing the notions that the research was synergistic and that data sharing is, in fact, an equitable enterprise.
The step-change increase in understanding polar systems attempted by IPY highlighted the central role that data and its management play in achieving that goal. There have been challenges in sharing and archiving data (Carlson, 2011), and the IPY experience illustrated that data handling is most successful when nations commit program resources to each phase of the data’s life (e.g., collection, reduction, distribution, and archiving). Experts in data management are critical members of any team attempting internationally coordinated science on the scale of IPY.
The contrasts between the Arctic and the Antarctic reflect onto the differences in how data are managed, increasing the difficulty of bipolar research. There are geopolitical and social dimensions in the Arctic that complicate data management and accessibility. National interests are stronger, cultural and health issues abound, and each is changing rapidly as the Arctic physical environment changes. The International Arctic Science Committee (IASC) and SCAR are the natural organizations to coordinate data management in the two poles, but presently they do not have a consistent data policy. The IPY data subcommittee suggested a new CODATA Task Group to help plan a transition from IPYDIS to relevant international data structures and organizations and also recommended that IASC and SCAR work with this task group to create a single polar data policy and associated data management procedures and structures.
The effort exerted during IPY toward networking various data centers should continue and expand into the future. Today, the rapid exchange of vast data volumes allows a distributed data center, and IPY used this to advantage in linking data sets hosted in widely separate data centers to form much larger virtual data centers (also the eGY concept). This trend will continue, but the partnerships between data centers need to be more than electronic links. To fully serve the needs of scientists strong in a single discipline but interested in multiple disciplines, the form and format of the data sets need to be modified to enable an increased level of interdisciplinary research. This will require collaborative planning on the part of data managers and scientists. It may not require changing the actual form of the data, but rather provision of interface tools that allow a data set to be understood by a variety of disciplinary experts.
Other considerations include institutional requirements for data release. Parsons et al. (2011) expressed the view that “the experience in IPY has shown that most effective enforcement mechanism is through funding mechanisms that either withhold some funding or reduce the ability of scientists to obtain future funding opportunities if they do not adhere to the data policy.” This is a familiar condition in the United States, where the NSF, which funds much of the polar research, imposes just such a requirement on funded investigators. In return for data shared by investigators and data managed by data centers, it is very important that users of the data provide proper and complete acknowledgment and credit these data in their subsequent use. Guidance for proper citation supplied by data centers is becoming more common. For example, with data sets archived in the National Snow and Ice Data Center, there is a sentence provided that explicitly states how the data and its archive should be referenced in documents that make use of the data. Understanding the data policies of all government funding entities involved is an important component for planning future international science endeavors like IPY.
The polar regions have always presented great logistical challenges because the terrain is vast, access can be difficult and expensive, the working conditions are invariably difficult, and the areas of interest frequently cross national boundaries. As a result, to adequately observe the large-scale systems interacting, international cooperation is frequently a necessity, requiring significant planning. Observation networks such as SAON, iAOOS, and SOOS developed and/ or expanded during IPY. IPY put in place the planning and infrastructure needed to develop long-term sustained measurement systems for the Arctic and Antarctic. The structure of these networks will continue to evolve as the data are analyzed and needs change. However, sustaining these systems in the long term will continue to present a challenge to the research community.
IPY saw numerous examples of first-time deployments of new tools for observing the polar climate, ecosystems, and beyond; examples include SeaGliders, unmanned aerial systems, and animal-borne ocean sensors. IPY also saw the use of existing tools in new ways and in new places. These new tools allowed for a more comprehensive observation of the poles than ever before. The use of remotely controlled autonomous observing systems became increasingly common, while the cost and complexity of these systems often made multiagency and/or international cooperation necessary. This was never more apparent than with satellite systems. IPY cannot claim credit for the generation of any new satellite missions, but it did succeed in an unprecedented set of coordinated observation from spaceborne sensors operated by multiple national space agencies. Through the IPY’s Space Task Group, this Polar Snapshot was so successful that the group has remained and continues to cooperate with national space agencies for observations intended to maintain an effective space-based monitoring of the polar regions to help overcome what is a decreasing observational capability as many satellite systems age and fail.
Observations are of little value if they are not available to researchers. However, the challenges to availability multiply as the data volumes increase and the needs of interdisciplinary research extend to data of unfamiliar form and content. A number of existing data centers in the United States stepped up to this challenge, making data management expertise available to IPY projects and following through with mechanisms to receive, organize, store, and make available metadata of all types that would assist researchers in locating data relevant to a wide range of scientific pursuits.