Global Characterization of Inland Water Reservoirs Using ICESat‐2 Altimetry and Climate Reanalysis. Issue 17 (28th August 2020)

• Record Type: Journal Article
• Authors: Ryan, Jonathan C.; Smith, Laurence C.; Cooley, Sarah W.; Pitcher, Lincoln H.; Pavelsky, Tamlin M.
• Is Part Of: Geophysical research letters. Volume 47:Issue 17(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-08-28
• Subjects: reservoirs -- remote sensing -- ICESat‐2 -- water resources; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1029/2020GL088543
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: Accurate, transparent knowledge of global reservoir levels is a prerequisite for effective management of water resources. However, no complete database exists because gauge data are not globally available and the current generation of satellite radar altimeters resolves only the world's largest reservoirs. Here, we investigate water level changes in global reservoirs using ICESat‐2, National Aeronautics and Space Administration (NASA)'s new satellite laser altimetry mission. In just the first 12 months of the mission, we find that ICESat‐2 accurately (±14.1 cm) retrieved water level changes for 3, 712 global reservoirs having surface areas ranging from <1 to >10, 000 km 2 . From this new global data set, we identify distinct regional patterns in reservoir level change that can be attributed to both water availability and management strategy. Our findings demonstrate that ICESat‐2 will form a crucial component of any global reservoir level inventory and enable new insight into how reservoir management responds to climatic variability and increasing human demand. Plain Language Summary: Freshwater reservoirs provide critical services (e.g., hydroelectricity generation, irrigation, and water supply) to societies around the world. However, global knowledge of reservoir water levels is limited because reservoir gauge data are often proprietary, difficult to access, or nonexistent, and the current generation of satellite radar altimeters can only resolve the world's largest reservoirs. Here, we demonstrate the potential of ICESat‐2, National Aeronautics and Space Administration (NASA)'s new laser altimetry mission, for accurately and transparently characterizing global reservoirs. We find high accuracy (±14.1 cm) of ICESat‐2 surface water observations as compared with 195 in situ reservoir level gauges. Next, we identify distinct regional patterns in global reservoir levels, many of which can readily be explained by reservoir function (e.g., hydropower generation). Our findings emphasize the critical role that humans have in regulating water flow across large areas of the Earth and demonstrate the potential of a new satellite technology for characterizing global reservoir response to climatic variability and human water demand. Key Points: We present a first assessment of ICESat‐2 altimetry for investigating changes in global freshwater reservoirs High accuracy of ICESat‐2 surface water retrievals is demonstrated through comparison with in situ reservoir gauges Distinct regional patterns in reservoir levels are identified, many of which can be explained by water availability and reservoir function