Using a Numerical Weather Model to Improve Geodesy
نویسنده
چکیده
The use of a Numerical Weather Model (NWM) to provide in situ atmosphere information for mapping functions of atmosphere delay has been evaluated using Very Long Baseline Interferometry (VLBI) data spanning eleven years. Parameters required by the IMF mapping functions (Niell 2000, 2001) have been calculated from the NWM of the National Centers for Environmental Prediction (NCEP) and incorporated in the CALC/SOLVE VLBI data analysis program. Compared with the use of the NMF mapping functions (Niell 1996) the application of IMF for global solutions demonstrates that the hydrostatic mapping function, IMFh, provides both significant improvement in baseline length repeatability and noticeable reduction in the amplitude of the residual harmonic site position variations at semidiurnal to long-period bands. For baseline length repeatability the reduction in the observed mean square deviations achieves 80% of the maximum that is expected for the change from NMF to IMF. On the other hand, the use of the wet mapping function, IMFw, as implemented using the NCEP data, results in a slight degradation of baseline length repeatability, probably due to the large grid spacing of the NWM that is used.
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Dave Wells is Professor Emeritus in the Dept. of Geodesy and Geomatics Engineering at UNB, as well as Professor in the Dept. of Marine Science at the University of Southern Mississippi (USM), and Adjunct Professor in the Center for Coastal and Ocean Mapping at the University of New Hampshire. Dave's academic interests include geodesy, applied bathymetry, kinematic positioning, water levels and ...
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