A general method for determining the key parameters of GNSS water vapor tomography modeling

doi:10.11947/j.AGCS.2025.20240293

Abstract

Abstract:

The existing global navigation satellite system (GNSS) water vapor tomography is mostly empirically selected in the determination of key parameters such as tomography height, vertical stratification, horizontal step size, etc., and lacks a general determination method, resulting in large differences in tomography results and difficulty in realizing the application of general water vapor tomography results. Because of this situation, this study proposes a theoretical method for determining the generality of key parameters of GNSS water vapor tomography to solve the problem that the optimal modeling parameters cannot be determined in the process of water vapor tomography. Firstly, the principle of determining the optimal height of the tomographic region by combining the vertical layered profile data and the water vapor density threshold is proposed. Secondly, the optimal vertical resolution determination method based on the equal weight principle of vertical stratified water vapor is proposed. Thirdly, considering the information on station density and satellite cut-off elevation angle, the optimal horizontal step size determination method based on the idea of joint grid coverage maximization and non-uniform symmetric horizontal grid division is developed. The data of 12 GNSS stations and 1 radiosonde station in Hong Kong from May 1 to 14, 2013 were selected for experiments. Compared with the existing classical methods, compared with radiosonde data, the average improvement rate of the retrieved water vapor density profile is 12%. Compared with the slant water vapor (SWV) calculated by the fifth-generation reanalysis dataset (ERA5) released by the European Centre for medium range weather forecasts (ECMWF), the average improvement rate of SWV obtained by the proposed scheme is 29.5%.

Key words: GNSS, water vapor tomography, key parameters, general method

CLC Number:

P228

Qingzhi ZHAO, Duoduo JIANG, Hongwu GUO, Zufeng LI, Chen LIU, Yibin YAO. A general method for determining the key parameters of GNSS water vapor tomography modeling[J]. Acta Geodaetica et Cartographica Sinica, 2025, 54(3): 410-421.

Figures/Tables 8

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方案	层析高度/km	垂直分层（由低到高）/km	经纬度方向水平步长/（°）
方案T1^[13]	9.93	0.993、0.993、0.993、0.993、0.993、0.993、0.993、0.993、0.993、0.993	经度：0.06、0.06、0.06、0.06、0.06、0.06、0.06、0.06 纬度：0.06、0.06、0.06、0.06、0.06、0.06
方案T2^[41]	8.50	0.4、0.4、0.4、0.4、0.4、0.5、0.5、0.5、0.5、0.6、0.6、0.6、0.7、1.0、1.0	经度：0.06、0.06、0.06、0.06、0.06、0.06、0.06、0.06 纬度：0.06、0.06、0.06、0.06、0.06、0.06
方案T3^[12]	8.00	0.5、0.5、0.7、0.7、0.7、0.9、0.9、0.9、1.1、1.1	经度：0.06、0.06、0.06、0.06、0.06、0.06、0.06、0.06 纬度：0.06、0.06、0.06、0.06、0.06、0.06
方案G1	9.93	0.26、0.28、0.32、0.35、0.40、0.46、0.57、0.79、1.37、5.13	经度：0.08、0.07、0.05、0.04、0.04、0.05、0.07、0.08 纬度：0.09、0.06、0.03、0.03、0.06、0.09
方案G2	9.93	0.26、0.28、0.32、0.35、0.40、0.46、0.57、0.79、1.37、5.13	经度：0.08、0.07、0.05、0.04、0.04、0.05、0.07、0.08 纬度：0.1、0.05、0.03、0.03、0.05、0.1
方案G3	9.93	0.26、0.28、0.32、0.35、0.40、0.46、0.57、0.79、1.37、5.13	经度：0.09、0.06、0.05、0.04、0.04、0.05、0.06、0.09 纬度：0.09、0.06、0.03、0.03、0.06、0.09
方案G4	9.93	0.26、0.28、0.32、0.35、0.40、0.46、0.57、0.79、1.37、5.13	经度：0.09、0.06、0.05、0.04、0.04、0.05、0.06、0.09 纬度：0.1、0.05、0.03、0.03、0.05、0.1