Using Satellite Altimetry to Measure Lake Volume Changes in the Western U.S.

Monitoring changes in lake volumes globally in the Western U.S is essential for understanding the hydrologic response to climate change and for predicting the physical and ecological response to vanishing water resources. Unfortunately, the monitoring of lakes in many areas of the world is limited by local resources, so that fluctuations in volumes over time are poorly known. This makes managing water resources difficult. In this study, we test the viability of using space-based LIDAR altimetry data as a tool to measure changes in lake elevation which is then used to calculate changes in volume over time. The study concentrates on the Western U.S., where there are relatively long records of lake levels to test the methodology. By coupling LIDAR elevation measurements from the ICESat satellite with bathymetry curves, lake volumes can be calculated. To test the robustness of ICESat elevation measurements over water, we used two hydrologically distinct test lakes (Lake Tahoe and Great Salt Lake) which have in-situ daily elevation measurements from USGS gauging stations. Once this proof of concept was confirmed and the associated uncertainty determined, we applied this method to Lake Abert, Pyramid Lake and Walker Lake. This study affirms that using ICESat LIDAR altimetry data is a viable option to estimate the volumes unmonitored lakes. As more satellite altimetry missions come online, long term space-based monitoring of lakes will become increasingly feasible, which will help improve our understanding of global water resources in a rapidly changing climate