Preprints
https://doi.org/10.5194/egusphere-2023-613
https://doi.org/10.5194/egusphere-2023-613
05 May 2023
 | 05 May 2023
Status: this preprint is open for discussion and under review for Atmospheric Measurement Techniques (AMT).

Impact Analysis of processing strategies on Long-term GPS ZTD

Jingna Bai, Yidong Lou, Weixing Zhang, Yaozong Zhou, Zhenyi Zhang, Chuang Shi, and Jingnan Liu

Abstract. Homogenized atmospheric water vapor is an important prerequisite for climate analysis. Compared with other techniques, GPS has inherent homogeneity advantage, but it still requires reprocessing and homogenization to eliminate impacts of applied strategy and observation environmental changes where a selection of proper processing strategies is critical. This paper comprehensively investigates an influence of the mapping function, the elevation cut-off angle and homogenization on long-term reprocessing results, in particular for Zenith Tropospheric Delays (ZTD) products, by using GPS observations at 46 IGS stations during 1995 to 2014. In the analysis, for the first time, we included the latest mapping function (VMF3) and exploited homogenized radiosonde data as a reference for ZTD trend evaluations. Our analysis shows that both site position and ZTD solutions achieved the best accuracy when using VMF3 and 3° elevation cut-off angle. Regarding the long-term ZTD trends, results show that the impact of mapping functions is very small, with a maximum difference of 0.3 mm/yr. On the other hand, the discrepancy can reach 2.5 mm/yr by using different elevation cut-off angles. Contrary to recommendations by previous studies, the low elevation cut-off angles (3° or 7°) are suggested for the best estimates of ZTD reprocessing time series when compared to homogenized radiosonde data or ERA5 reference time series. This conclusion has great significance by eliminating the conflict of different optimal elevation cut-off angles for climate analysis and other applications from GNSS data reprocessing.

Jingna Bai et al.

Status: open (until 09 Jun 2023)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-613', Anonymous Referee #1, 22 May 2023 reply
  • RC2: 'Comment on egusphere-2023-613', Anonymous Referee #2, 24 May 2023 reply

Jingna Bai et al.

Jingna Bai et al.

Viewed

Total article views: 151 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
121 22 8 151 2 2
  • HTML: 121
  • PDF: 22
  • XML: 8
  • Total: 151
  • BibTeX: 2
  • EndNote: 2
Views and downloads (calculated since 05 May 2023)
Cumulative views and downloads (calculated since 05 May 2023)

Viewed (geographical distribution)

Total article views: 154 (including HTML, PDF, and XML) Thereof 154 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 04 Jun 2023
Download
Short summary
Homogenized atmospheric water vapor is an important prerequisite for climate analysis. Compared with other techniques, GPS has inherent homogeneity advantage, but it still requires reprocessing and homogenization to eliminate impacts of applied strategy and observation environmental changes. The low elevation cut-off angles are suggested for the best estimates of ZTD reprocessing time series when compared to homogenized radiosonde data or ERA5 reference time series.