Civil Engineering and Geosciences

	Dr Ian Thomas Research Associate Phone: ian.thomas@ncl.ac.uk
main expertise/research interests
Global GPS geodesy, focusing on the use of up to date models and GPS processing strategies to obtain accurate geophysical measurements. Recent work has included: 1. GPS determination of crustal displacements resulting from Ocean Tide Loading (OTL), globally and regionally in Antarctica. The GPS measurements have been validated against estimates from Very Long Baseline Interferometry (VLBI), and compared against values computed from numerical ocean tide models. 2. Measurement of atmospheric water vapour over Antarctica, from globally reprocessed GPS solutions. The work included comparison of the measurements with radiosonde and other satellite datasets and analysis of the ~12 year GPS derived time series for meteorological and climatological signals.
current work
Reanalysis of raw GPS data in global solutions with the aim of obtaining accurate surface velocity fields. GPS Data from the early 1990s up until the present day and from several hundred permenantly recording GPS receivers, is to processed in a consistent manner, using the latest GPS models. The resulting velocities will be useful for various studies, for example providing constraints on Glacial Isostatic Adjustment (GIA) models and for correcting tide gauges for their vertical motion.