The NASA Socioeconomic Data and Applications Center (SEDAC) operated by CIESIN has recently released three global data sets that utilize satellite-based remote sensing data to help characterize critical aspects of human-environment interactions: Trends in Global Freshwater Availability from the Gravity Recovery and Climate Experiment (GRACE), v1 (2002 – 2016), Development Threat Index, v1 (2015), and Altimeter Corrected Elevations (ACE2), v2 (1994 – 2005).
The ability to measure trends in global freshwater availability has been made possible by NASA′s Gravity Recovery and Climate Experiment (GRACE). By measuring small changes in Earth′s gravity field, the GRACE mission was able to track key dynamics of the global water cycle at a spatial resolution of 0.5 degrees during the period from 2002 to 2016. Terrestrial water availability storage is the sum of groundwater, soil moisture, snow and ice, surface waters, and wet biomass, expressed as an equivalent height of water. The data are valuable in helping to evaluate and predict emerging threats to water and food security. Part of SEDAC's Satellite-Derived Environmental Indicators (SDEI) data collection, the data set was developed by researchers from the NASA Goddard Space Flight Center and Jet Propulsion Laboratory and from National Taiwan University.
The Development Threat Index, v1 seeks to map terrestrial global, future development threats resulting from agricultural expansion, urban expansion, and energy development (conventional oil and gas, unconventional oil and gas, coal, mining, biofuels, solar, and wind). Individual threat layers draw on several different data sets derived in part from satellite remote sensing data, including the Global Grid of Probabilities of Urban Expansion to 2030, the Global Roads Open Access Data Set (gROADS), and the Global Reservoir and Dam (GRanD) data sets, all available through SEDAC. The Index has been produced on a 50 square kilometer grid by a team from The Nature Conservancy, the University of Minnesota, and the University of British Columbia. It has been added to SEDAC′s Land Use and Land Cover (LULC) data collection, but shares similar objectives with the Human Footprint data also distributed by SEDAC (e.g., Human Footprint, 2018 Release).
The ACE2 data set is based on a Global Digital Elevation Model (GDEM) derived primarily from multi-mission Satellite Radar Altimetry in combination with data from the Shuttle Radar Topography Mission (SRTM). By using data from an altimeter, an instrument that uses radar to measure height, researchers were able to better assess ground elevation in areas with high tree cover. This represents an improvement over the original SRTM data, which only measured the top of the canopy. ACE2 is intended for research and applications such as flood risk assessment, landslide modelling, urban planning, and sea level rise impact assessment. In light of ongoing efforts to improve GDEMs, SEDAC has decided to preserve this version for future analysis and intercomparison as part of a new Digital Elevation Data Collection (DEDC). The data set was developed by a team from the UK and the European Space Agency.