This seminar by Dr Bridget Scanlon on how GRACE satellites track water storage variability as a result of both human and climate drivers. 

About the seminar

Increasing climate extremes, including droughts and floods, and rising human water demand is challenging for water resource managers. Two decades of GRACE (Gravity Recovery and Climate Experiment) satellite data have significantly advanced our understanding of global hydrology. GRACE measures variations in Earth’s gravity which are controlled mostly by water storage changes. Vertically integrated land total water storage (TWS) variations monitored by GRACE include surface water, soil moisture, and groundwater. The value of the GRACE TWS parameter is evident in its recent adoption in the IPCC reports as an essential parameter in assessing climate impacts in hydrology and increasing use of TWS in global models. GRACE is like a scale in the sky, providing the big picture, and ideal for monitoring freshwater contributions to sea level rise.

Attribution analysis of GRACE water storage variability to human and climate drivers has greatly advanced over time. GRACE satellites were the first to show large scale groundwater depletion in the IndoGangetic Basin. Interpretation of GRACE water storage has improved by integrating additional data on climate drivers (e.g., precipitation, drought indices) and human intervention (e.g., groundwater pumping, water use, land use change). Some basins show combined effects of human intervention amplifying or dampening climate effects. Recent studies show the value of ground-based monitoring and regional modeling to provide long-term context for GRACE data with large scale net increases in water storage in the IndoGangetic Basin and Northwest US over the past century.

A variety of approaches are available to increase system resilience to climate impacts and human water use, including increasing supplies (desalination, wastewater reuse, reducing demands (conservation), storing water (reservoirs, managed aquifer recharge), and transporting water (interbasin transfers, virtual water transfers). We will need a portfolio of options to address increasing climate extremes and human water demand in the future.

About the speaker

Bridget Scanlon is a Senior Research Scientist at the Bureau of Economic Geology, Jackson School of Geosciences, University of Texas at Austin. Her degrees are in Geology with a focus on hydrogeology with a B.A. Mod. from Trinity College, Dublin (1980); M.Sc. from the Univ. of Alabama (1983), and Ph.D. from the Univ. of Kentucky (1985). She has worked at the Univ. of Texas since 1987. Her current research focuses on various aspects of water resources, including global assessments using satellites and modeling, management related to climate extremes, and water energy interdependence. She serves an Associate Editor for Water Resources Research and Environmental Research Letters and has authored ~ or co-authored ~170 publications. Dr. Scanlon is a Fellow of the American Geophysical Union and the Geological Society of America and a member of the National Academy of Engineering.