Optimization of GPS water vapor tomography technique with radiosonde and COSMIC historical data
The near-real-time high spatial resolution of atmospheric water vapor distribution is vital in numerical weather prediction. GPS tomography technique has been proved effectively for three-dimensional water vapor reconstruction. In this study, the tomography processing is optimized in a few aspec...
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Series: | Annales Geophysicae |
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doaj-00a8fe39f656487b99f62c9b345ee7d32020-11-25T02:02:30ZengCopernicus PublicationsAnnales Geophysicae0992-76891432-05762016-09-013478979910.5194/angeo-34-789-2016Optimization of GPS water vapor tomography technique with radiosonde and COSMIC historical dataS. Ye0P. Xia1C. Cai2GNSS Research Centre, Wuhan University, Wuhan, 430079, ChinaGNSS Research Centre, Wuhan University, Wuhan, 430079, ChinaSchool of Geosciences and Info-physics, Central South University, Changsha, 410083, ChinaThe near-real-time high spatial resolution of atmospheric water vapor distribution is vital in numerical weather prediction. GPS tomography technique has been proved effectively for three-dimensional water vapor reconstruction. In this study, the tomography processing is optimized in a few aspects by the aid of radiosonde and COSMIC historical data. Firstly, regional tropospheric zenith hydrostatic delay (ZHD) models are improved and thus the zenith wet delay (ZWD) can be obtained at a higher accuracy. Secondly, the regional conversion factor of converting the ZWD to the precipitable water vapor (PWV) is refined. Next, we develop a new method for dividing the tomography grid with an uneven voxel height and a varied water vapor layer top. Finally, we propose a Gaussian exponential vertical interpolation method which can better reflect the vertical variation characteristic of water vapor. GPS datasets collected in Hong Kong in February 2014 are employed to evaluate the optimized tomographic method by contrast with the conventional method. The radiosonde-derived and COSMIC-derived water vapor densities are utilized as references to evaluate the tomographic results. Using radiosonde products as references, the test results obtained from our optimized method indicate that the water vapor density accuracy is improved by 15 and 12 % compared to those derived from the conventional method below the height of 3.75 km and above the height of 3.75 km, respectively. Using the COSMIC products as references, the results indicate that the water vapor density accuracy is improved by 15 and 19 % below 3.75 km and above 3.75 km, respectively.https://www.ann-geophys.net/34/789/2016/angeo-34-789-2016.pdf |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
S. Ye P. Xia C. Cai |
spellingShingle |
S. Ye P. Xia C. Cai Optimization of GPS water vapor tomography technique with radiosonde and COSMIC historical data Annales Geophysicae |
author_facet |
S. Ye P. Xia C. Cai |
author_sort |
S. Ye |
title |
Optimization of GPS water vapor tomography technique with radiosonde and
COSMIC historical data |
title_short |
Optimization of GPS water vapor tomography technique with radiosonde and
COSMIC historical data |
title_full |
Optimization of GPS water vapor tomography technique with radiosonde and
COSMIC historical data |
title_fullStr |
Optimization of GPS water vapor tomography technique with radiosonde and
COSMIC historical data |
title_full_unstemmed |
Optimization of GPS water vapor tomography technique with radiosonde and
COSMIC historical data |
title_sort |
optimization of gps water vapor tomography technique with radiosonde and
cosmic historical data |
publisher |
Copernicus Publications |
series |
Annales Geophysicae |
issn |
0992-7689 1432-0576 |
publishDate |
2016-09-01 |
description |
The near-real-time high spatial resolution of atmospheric water vapor
distribution is vital in numerical weather prediction. GPS tomography
technique has been proved effectively for three-dimensional water vapor
reconstruction. In this study, the tomography processing is optimized in a
few aspects by the aid of radiosonde and COSMIC historical data. Firstly,
regional tropospheric zenith hydrostatic delay (ZHD) models are improved and
thus the zenith wet delay (ZWD) can be obtained at a higher accuracy.
Secondly, the regional conversion factor of converting the ZWD to the
precipitable water vapor (PWV) is refined. Next, we develop a new method for
dividing the tomography grid with an uneven voxel height and a varied water
vapor layer top. Finally, we propose a Gaussian exponential vertical
interpolation method which can better reflect the vertical variation
characteristic of water vapor. GPS datasets collected in Hong Kong in
February 2014 are employed to evaluate the optimized tomographic method by
contrast with the conventional method. The radiosonde-derived and
COSMIC-derived water vapor densities are utilized as references to evaluate
the tomographic results. Using radiosonde products as references, the test
results obtained from our optimized method indicate that the water vapor
density accuracy is improved by 15 and 12 % compared to those derived from the
conventional method below the height of 3.75 km and above the height of
3.75 km, respectively. Using the COSMIC products as references, the results
indicate that the water vapor density accuracy is improved by 15 and 19 %
below 3.75 km and above 3.75 km, respectively. |
url |
https://www.ann-geophys.net/34/789/2016/angeo-34-789-2016.pdf |
work_keys_str_mv |
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