Date of Award

Spring 1-1-2019

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Aerospace Engineering Sciences

First Advisor

Robert S. Nerem

Second Advisor

Bryant D. Loomis

Third Advisor

Jay W. McMahon

Fourth Advisor

Tomoko Matsuo

Fifth Advisor

Ben Livneh

Abstract

The Gravity Recovery and Climate Experiment (GRACE) has created a more than 15 year record of time variable gravity and enabled studies of regional terrestrial water storage (TWS) changes. These and other studies have primarily been limited to analyses of long wavelength signals due to the inherent 30-day temporal resolution associated with the majority of GRACE products. This dissertation seeks to improve on this limitation by creating a daily estimate of TWS using mass concentrations (mascons) as an iteration of the Goddard Space Flight Center’s (GSFC) monthly global mascon product. The developed solution couples the 30-day high spatial resolution of that product with lower spatial resolution daily estimates. Key to this study is the development of an optimized regularization strategy for resolving daily fields that maximizes signal recovery and a characterization of bias in the solution due to this regularization. A rigorous analysis shows that the resulting daily estimated mascons have latitudinally-dependent resolution, with approximately 450 km spatial resolution in polar regions and 800-1,200 km spatial resolution at low latitudes. This analysis shows strong signal recovery relative to bias effects for basins larger than 800,000 sq. km and marginal recovery for basins 300,000-800,000 sq. km, while signal recovered in basins smaller than 250,000 sq. km are dominated by bias errors. The solution developed in this dissertation is the first daily TWS product with global land coverage estimated from individual daily GRACE Level-1B observations.

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