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| Titel |
Near real-time water vapor tomography using ground-based GPS and meteorological data: long-term experiment in Hong Kong |
| VerfasserIn |
P. Jiang, S. R. Ye, Y. Y. Liu, J. J. Zhang, P. F. Xia |
| 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 ; 32, no. 8 ; Nr. 32, no. 8 (2014-08-06), S.911-923 |
| Datensatznummer |
250121090
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| Publikation (Nr.) |
 copernicus.org/angeo-32-911-2014.pdf |
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| Zusammenfassung |
| Water vapor tomography is a promising technique for reconstructing the 4-D
moisture field, which is important to the weather forecasting and nowcasting
as well as to the numerical weather prediction. A near real-time 4-D water
vapor tomographic system is developed in this study. GPS slant water vapor
(SWV) observations are derived by a sliding time window strategy using
double-difference model and predicted orbits. Besides GPS SWV, surface water
vapor measurements are also assimilated as real time observations into the
tomographic system in order to improve the distribution of observations in
the lowest layers of tomographic grid. A 1-year term experiment in Hong
Kong was carried out. The feasibility of the GPS data processing strategy is
demonstrated by the good agreement between the time series of GPS-derived Precipitable Water Vapor
(PWV) and radio-sounding-derived PWV with a bias of 0.04 mm and a root-mean-square
error (RMSE) of 1.75 mm. Using surface humidity observations in the tomographic
system, the bias and RMSE between tomography and radiosonde data are
decreased by half in the ground level, but such improved effects weaken
gradually with the rise of altitude until becoming adverse above 4000 m.
The overall bias is decreased from 0.17 to 0.13 g m−3 and RMSE is
reduced from 1.43 to 1.28 g m−3. By taking the correlation coefficient and RMSE between tomography
and radiosonde individual profile as the statistical measures, quality of
individual profile is also improved as the success rate of tomographic
solution is increased from 44.44 to 63.82% while the failure rate is
reduced from 55.56 to 36.18%. |
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