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Titel |
Integrated water vapor from IGS ground-based GPS observations: initial results from a global 5-min data set |
VerfasserIn |
S. Heise, G. Dick, G. Gendt, T. Schmidt, J. Wickert |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
0992-7689
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Digitales Dokument |
URL |
Erschienen |
In: Annales Geophysicae ; 27, no. 7 ; Nr. 27, no. 7 (2009-07-16), S.2851-2859 |
Datensatznummer |
250016594
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Publikation (Nr.) |
copernicus.org/angeo-27-2851-2009.pdf |
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Zusammenfassung |
Ground based GPS zenith path delay (ZPD) measurements are well established as a
powerful tool for integrated water vapor (IWV) observation. The
International GNSS Service (IGS) provides ZPD data of currently
more than 300 globally distributed GPS stations. To derive IWV
from these data, meteorological information (ground pressure and
mean temperature above the station) are needed. Only a limited
number of IGS stations is equipped with meteorological ground
sensors up to now. Thus, meteorological data for IWV conversion
are usually derived from nearby ground meteorological observations
(ground pressure) and meteorological analyses (mean temperature).
In this paper we demonstrate for the first time the applicability
of ground pressure data from ECMWF meteorological analysis fields
in this context. Beside simplified data handling (no single station data and quality
control) this approach allows for IWV derivation if nearby
meteorological stations are not available.
Using ECMWF ground pressure and mean temperature
data the new IGS 5-min ZPD data set has been converted to IWV
for the first time. We present initial results from selected
stations with ground meteorological sensors including pressure and
temperature comparisons between ECMWF and local measurements. The
GPS IWV is generally validated by comparison with ECMWF IWV. The
ECMWF derived station meteorological data are compared with local
measurements at all accordingly equipped stations. Based on this
comparison, the mean error (in terms of standard deviation)
introduced by time interpolation of the
6-hourly ECMWF data is estimated below 0.2 mm IWV. |
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