Comparison of downscaled vertical GPS observations to independent measures of hydrologic loading

Quantifying integrated water load in areas of high topographic relief is extremely difficult and few observational constraints exist at scales relevant to hydrologic modeling or water management. Snow measurements and weather stations with very high spatial variability, and satellite observations don't resolve small mountain watersheds well. Present practices use a range of approaches to either interpolate point observations or empirically downscale remote observations. We leverage the fact that vertical displacement of Earth's surface measured with GNSS records the elastic response of the Earth to a combination of regional and local loading signals arising from hydrologic mass transfer (as well as other sources) to develop a method to separate estimated regional and local water loading. We then compare the GNSS-derived local hydrologic load changes at watershed scales of 10s of kilometers to other measures of hydrologic load to test whether GNSS can provide constraints on hydrologic load change at an important spatial scale between the existing long-wavelength resolution of satellite observations and point measurement resolution of a weather station.