A New Grid Model for Estimation of Zenith Tropospheric Delay Considering Vertical Adjustment Based on Gaussian Function over China

Abstract

Zenith tropospheric delay (ZTD) play an important role in the troposphere. This study proposed a new ZTD vertical profile grid model considering the height scale factor (NGZTD-H) based on the Gaussian function that adjusts the ZTD from the starting to the target height. To estimate the ZTD directly, a new NGZTD that considers the ZTD delicate diurnal variation was developed. The effectiveness of vertical and spatial interpolation for the NGZTD-H model was validated. Regarding vertical interpolation, the root mean squared error (RMSE) of the NGZTD-H model improved by 58% and 22%, compared to the global pressure and temperature 3 (GPT3) model. For spatial interpolation, the RMSE of the NGZTD-H model improved by 17% compared to that of the GPT3 model. The NGZTD model’s effectiveness for directly estimating the ZTD was validated. The NGZTD model improved by 22% and 31% compared to the GPT3 model using GNSS-derived ZTD and layered ZTD at radiosonde stations, respectively. The NGZTD model exhibited outstanding advantages in capturing diurnal variations and adapting to undulating terrain. This new ZTD model has potential applications in enhancing the reliability of navigation, positioning, and interferometric synthetic aperture radar (InSAR) measurements and is recommended to promote the development of space geodesy techniques.