The Performance of Different Mapping Functions and Gradient Models in the Determination of Slant Tropospheric Delay
Global navigation satellite systems (GNSSs) have become an important tool for remotely sensing water vapor in the atmosphere. In GNSS data processing, mapping functions and gradient models are needed to map the zenith tropospheric delay (ZTD) to the slant total tropospheric delay (STD) along a signa...
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ftdoajarticles:oai:doaj.org/article:eff6da1be96b4812a598ad5d39a8c296 2023-05-15T17:40:01+02:00 The Performance of Different Mapping Functions and Gradient Models in the Determination of Slant Tropospheric Delay Cong Qiu Xiaoming Wang Zishen Li Shaotian Zhang Haobo Li Jinglei Zhang Hong Yuan 2020-01-01T00:00:00Z https://doi.org/10.3390/rs12010130 https://doaj.org/article/eff6da1be96b4812a598ad5d39a8c296 EN eng MDPI AG https://www.mdpi.com/2072-4292/12/1/130 https://doaj.org/toc/2072-4292 2072-4292 doi:10.3390/rs12010130 https://doaj.org/article/eff6da1be96b4812a598ad5d39a8c296 Remote Sensing, Vol 12, Iss 1, p 130 (2020) tropospheric delay mapping function gradient models bending effect Science Q article 2020 ftdoajarticles https://doi.org/10.3390/rs12010130 2022-12-31T16:09:24Z Global navigation satellite systems (GNSSs) have become an important tool for remotely sensing water vapor in the atmosphere. In GNSS data processing, mapping functions and gradient models are needed to map the zenith tropospheric delay (ZTD) to the slant total tropospheric delay (STD) along a signal path. Therefore, it is essential to investigate the spatial−temporal performance of various mapping functions and gradient models in the determination of STD. In this study, the STDs at nine elevations were first calculated by applying the ray-tracing method to the atmospheric European Reanalysis-Interim (ERA—Interim) dataset. These STDs were then used as the reference to study the accuracy of the STDs that determined the ZTD together with mapping functions and gradient models. The performance of three mapping functions (i.e., Niell mapping function (NMF), global mapping function (GMF), and Vienna mapping function (VMF1)) and three gradient models (i.e., Chen, MacMillan, and Meindl) in six regions (the temperate zone, Qinghai−Tibet Plateau, Equator, Sahara Desert, Amazon Rainforest, and North Pole) in determining slant tropospheric delay was investigated in this study. The results indicate that the three mapping functions have relatively similar performance above a 15° elevation, but below a 15° elevation, VMF1 clearly performed better than the GMF and NMF. The results also show that, if no gradient model is included, the root-mean-square (RMS) of the STD is smaller than 2 mm above the 30° elevation and smaller than 9 mm above the 15° elevation but shows a significant increase below the 15° elevation. For example, in the temperate zone, the RMS increases from approximately 35 mm at the 10° elevation to approximately 160 mm at the 3° elevation. The inclusion of gradient models can significantly improve the accuracy of STDs by 50%. All three gradient models performed similarly at all elevations and in all regions. The bending effect was also investigated, and the results indicate that the tropospheric delay caused by ... Article in Journal/Newspaper North Pole Directory of Open Access Journals: DOAJ Articles North Pole Remote Sensing 12 1 130 |
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Open Polar |
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Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
tropospheric delay mapping function gradient models bending effect Science Q |
spellingShingle |
tropospheric delay mapping function gradient models bending effect Science Q Cong Qiu Xiaoming Wang Zishen Li Shaotian Zhang Haobo Li Jinglei Zhang Hong Yuan The Performance of Different Mapping Functions and Gradient Models in the Determination of Slant Tropospheric Delay |
topic_facet |
tropospheric delay mapping function gradient models bending effect Science Q |
description |
Global navigation satellite systems (GNSSs) have become an important tool for remotely sensing water vapor in the atmosphere. In GNSS data processing, mapping functions and gradient models are needed to map the zenith tropospheric delay (ZTD) to the slant total tropospheric delay (STD) along a signal path. Therefore, it is essential to investigate the spatial−temporal performance of various mapping functions and gradient models in the determination of STD. In this study, the STDs at nine elevations were first calculated by applying the ray-tracing method to the atmospheric European Reanalysis-Interim (ERA—Interim) dataset. These STDs were then used as the reference to study the accuracy of the STDs that determined the ZTD together with mapping functions and gradient models. The performance of three mapping functions (i.e., Niell mapping function (NMF), global mapping function (GMF), and Vienna mapping function (VMF1)) and three gradient models (i.e., Chen, MacMillan, and Meindl) in six regions (the temperate zone, Qinghai−Tibet Plateau, Equator, Sahara Desert, Amazon Rainforest, and North Pole) in determining slant tropospheric delay was investigated in this study. The results indicate that the three mapping functions have relatively similar performance above a 15° elevation, but below a 15° elevation, VMF1 clearly performed better than the GMF and NMF. The results also show that, if no gradient model is included, the root-mean-square (RMS) of the STD is smaller than 2 mm above the 30° elevation and smaller than 9 mm above the 15° elevation but shows a significant increase below the 15° elevation. For example, in the temperate zone, the RMS increases from approximately 35 mm at the 10° elevation to approximately 160 mm at the 3° elevation. The inclusion of gradient models can significantly improve the accuracy of STDs by 50%. All three gradient models performed similarly at all elevations and in all regions. The bending effect was also investigated, and the results indicate that the tropospheric delay caused by ... |
format |
Article in Journal/Newspaper |
author |
Cong Qiu Xiaoming Wang Zishen Li Shaotian Zhang Haobo Li Jinglei Zhang Hong Yuan |
author_facet |
Cong Qiu Xiaoming Wang Zishen Li Shaotian Zhang Haobo Li Jinglei Zhang Hong Yuan |
author_sort |
Cong Qiu |
title |
The Performance of Different Mapping Functions and Gradient Models in the Determination of Slant Tropospheric Delay |
title_short |
The Performance of Different Mapping Functions and Gradient Models in the Determination of Slant Tropospheric Delay |
title_full |
The Performance of Different Mapping Functions and Gradient Models in the Determination of Slant Tropospheric Delay |
title_fullStr |
The Performance of Different Mapping Functions and Gradient Models in the Determination of Slant Tropospheric Delay |
title_full_unstemmed |
The Performance of Different Mapping Functions and Gradient Models in the Determination of Slant Tropospheric Delay |
title_sort |
performance of different mapping functions and gradient models in the determination of slant tropospheric delay |
publisher |
MDPI AG |
publishDate |
2020 |
url |
https://doi.org/10.3390/rs12010130 https://doaj.org/article/eff6da1be96b4812a598ad5d39a8c296 |
geographic |
North Pole |
geographic_facet |
North Pole |
genre |
North Pole |
genre_facet |
North Pole |
op_source |
Remote Sensing, Vol 12, Iss 1, p 130 (2020) |
op_relation |
https://www.mdpi.com/2072-4292/12/1/130 https://doaj.org/toc/2072-4292 2072-4292 doi:10.3390/rs12010130 https://doaj.org/article/eff6da1be96b4812a598ad5d39a8c296 |
op_doi |
https://doi.org/10.3390/rs12010130 |
container_title |
Remote Sensing |
container_volume |
12 |
container_issue |
1 |
container_start_page |
130 |
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1766140802061303808 |