HR: 09:00h
AN: G51D-05 INVITED    [Abstracts]
TI: Numerical Weather Models for Troposphere Delay Modelling at Radio Wavelengths
AU: * Schuh, H
EM: harald.schuh@tuwien.ac.at
AF: Vienna University of Technology, Gusshausstrasse 27-29, Vienna, 1040, Austria
AU: Boehm, J
EM: johannes.boehm@tuwien.ac.at
AF: Vienna University of Technology, Gusshausstrasse 27-29, Vienna, 1040, Austria
AB: Data from numerical weather models (NWM) have been successfully used to develop and improve models for the tropospheric delays as applied in the analysis of Global Positioning System (GPS), Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) or Very Long Baseline Interferometry (VLBI) observations. Tropospheric delays are usually divided into a hydrostatic and a wet part, and both of them are set up as the product of the respective zenith delay and mapping function. Whereas the hydrostatic zenith delay can be determined from empirical models, 6 hour surface pressure values from NWM or in situ pressure recordings, the wet zenith delay is estimated in the analysis of space geodetic data. The mapping functions which account for the elevation dependence of the delays can be derived routinely from 6 hour NWM data like the Vienna Mapping Functions (VMF1), or they can be represented as an empirical model like the Niell Mapping Functions (NMF) or the Global Mapping Functions (GMF), the latter being consistent with the VMF1 over longer time spans. State of the art analyses also include the estimation of tropospheric gradients which account for the azimuthal asymmetries of the delays. We compare the influence of different types of a priori gradients (empirical model, station dependent values, 6 hour values from NWM) on the terrestrial and celestial reference frame in GPS and VLBI analysis.
DE: 1220 Atmosphere monitoring with geodetic techniques (6952)
DE: 1229 Reference systems
DE: 1240 Satellite geodesy: results (6929, 7215, 7230, 7240)
DE: 1295 Integrations of techniques
SC: Geodesy [G]
MN: 2007 Fall Meeting