IGCP 565 Workshop 3: Separating Hydrological and Tectonic Signals in Geodetic Observations Reno, Nevada, October 11-13, 2010

P3: Case Studies: The South West of the U.S. and East Africa

Co-chairs: Norman Miller (UCB), Elias Lewi (Addis Ababa University), Eric Callais (PUD)

One of the two focal geographical regions is the Southwest of the U.S., where significant changes are taking place in hydrology and where tectonic processes contribute secular and transient signals to geodetic observations. The goal of this session is to give an overview of the relevant processes, to assess the state of knowledge, to discuss the observing system, and to characterize the observed or expected signals.

The recent western US droughts have significantly lowered groundwater levels, impacting water resource availability. Regions of overdraft have also resulted in subsidence, especially where clay soils have dried down. Application of GRACE and GPS has emerged as new tools for monitoring such terrestrial water storage (TWS) change, however the scale of application remains on order 150,000 km2. Ground truth via well data has helped to provide validations of geodetic derived changes in the TWS. Removal of TWS terms, such as the soil moisture, snow water equivalent, and surface water reservoirs requires additional data based on a combination of observations and simulations. Land surface models calculate soil moisture and snow water equivalent and can be evaluated with additional remote sensed data (e.g. National Operational Hydrologic Remote Sensing Center).This session seeks to provide a forum for discussing and advancing new and advanced approaches for improving ground based observations with remote sensing to develop high resolution estimates of change in TWS and geodetic response.

The second focal geographical region is East Africa, where significant hydrological and tectonic signals are superimposed. The goal of the session is to identify the relevant processes, to introduce on-going studies, to given an overview of existing and planned observation infrastructure, and to discuss the science challenges.