Original Research ARTICLE
Water storage trends in High Mountain Asia
- 1Goddard Space Flight Center, National Aeronautics and Space Administration, United States
- 2Washington State University, United States
- 3Applied Physics Laboratory, University of Washington, United States
- 4University of Maryland, College Park, United States
- 5University of Washington, United States
Changes in terrestrial water storage (TWS) in High Mountain Asia (HMA) could have major societal impacts, as the region’s large reservoirs of glaciers, snow, and groundwater provide a freshwater source to more than one billion people. We seek to quantify and close the budget of secular changes in TWS over the span of the GRACE satellite mission (2003-2016). To assess the TWS trend budget we consider a new high-resolution mass trend product determined directly from GRACE L1B data, glacier mass balance derived from Digital Elevation Models (DEMs), groundwater variability determined from confined and unconfined well observations, and terrestrial water budget estimates from a suite of land surface model simulations with the NASA Land Information System (LIS).
This effort is successful at closing the aggregated TWS trend budget over the entire HMA region, the glaciated portion of HMA, and the Indus and Ganges basins, where the full-region trends are primarily due to the glacier mass balance and groundwater signals. Additionally, we investigate the closure of TWS trends at individual 1-arc-degree mascons (area $\approx$12,000 km$^2$); a significant improvement in spatial resolution over previous analyses of GRACE-derived trends. This mascon-level analysis reveals locations where the TWS trends are well-explained by the independent datasets, as well as regions where they are not; identifying specific geographic areas where additional data and model improvements are needed. The accurate characterization of total TWS trends and its components presented here is critical to understanding the complex dynamics of the region, and is a necessary step towards projecting future water mass changes in HMA.
Keywords: Terrestrial water storage (TWS), GRACE mascons, Glacier mass balance, Groundwater (G.W.), Land information system (LIS), High Mountain Asia (HMA)
Received: 17 May 2019;
Accepted: 28 Aug 2019.
Copyright: © 2019 Loomis, Richey, Arendt, Appana, Deweese, Forman, Kumar, Sabaka and Shean. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Dr. Bryant Loomis, Goddard Space Flight Center, National Aeronautics and Space Administration, Greenbelt, United States, firstname.lastname@example.org