GPS ensemble analysis applied to Antarctic vertical velocities

Abstract:

GPS data is used to provide estimates of vertical land motion caused by e.g. glacial isostatic adjustment (GIA) and hydrologic loading. The vertical velocities estimated from the GPS data are often assimilated into GIA models or used for comparison purposes. GIA models are very important as they provide time-variable gravity corrections needed to estimate ice mass change over Greenland and Antarctica.

While state-of-the art global GPS analysis has previously been performed for many Antarctic sites, formal errors in the resulting site velocities are typically obtained from noise analysis of each individual time series without consideration of processing or metadata issues. Here we present analysis of the results from two full global runs including a variety of parameter and reference frame alignment choices, and compare the results to previous work with a view to assessing if the size of the formal errors from the standard method is truly representative.