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Evaluation of Atmospheric Loading and Improved Troposphere ModellingForward modeling of non-tidal atmospheric loading displacements at geodetic tracking stations have not routinely been included in Doppler Orbitography and Radiopositionning Integrated by Satellite (DORIS) or Satellite Laser Ranging (SLR) station analyses for either POD applications or reference frame determination. The displacements which are computed from 6-hourly models such as the ECMWF and can amount to 3-10 mm in the east, north and up components depending on the tracking station locations. We evaluate the application of atmospheric loading in a number ways using the NASA GSFC GEODYN software: First we assess the impact on SLR & DORIS-determined orbits such as Jason-2, where we evaluate the impact on the tracking data RMS of fit and how the total orbits are changed with the application of this correction. Preliminary results show an RMS radial change of 0.5 mm for Jason-2 over 54 cycles and a total change in the Z-centering of the orbit of 3 mm peak-to-peak over one year. We also evaluate the effects on other DORIS-satellites such as Cryosat-2, Envisat and the SPOT satellites. In the second step, we produce two SINEX time series based on data from available DORIS satellites and assess the differences in WRMS, scale and Helmert translation parameters. Troposphere refraction is obviously an important correction for radiometric data types such as DORIS. We evaluate recent improvements in DORIS processing at GSFC including the application of the Vienna Mapping Function (VMF1) grids with a-priori hydrostatic (VZHDs) and wet (VZWDs) zenith delays. We reduce the gridded VZHD at the stations height using pressure and temperature derived from GPT (strategy 1) and Saastamoinen. We discuss the validation of the VMF1 implementation and its application to the Jason-2 POD processing, compared to corrections using the Niell mapping function and the GMF. Using one year of data, we also assess the impact of the new troposphere corrections on the DORIS-only solutions, most importantly on the scale of the weekly solutions.
Document ID
20120013864
Acquisition Source
Goddard Space Flight Center
Document Type
Conference Paper
Authors
Zelensky, Nikita P.
(SGT, Inc. Greenbelt , MD, United States)
Chinn, Douglas S.
(SGT, Inc. Greenbelt , MD, United States)
Lemoine, F. G.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Le Bail, Karine
(NVI, Inc. Greenbelt, MD, United States)
Pavlis, Despina E.
(SGT, Inc. Greenbelt , MD, United States)
Date Acquired
August 26, 2013
Publication Date
January 1, 2012
Subject Category
Geophysics
Report/Patent Number
GSFC.ABS.6912.2012
Distribution Limits
Public
Copyright
Other

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