WTM: The Site-Wise Empirical Wuhan University Tropospheric Model

The tropospheric model is the key in space geodetic techniques such as Global Navigation Satellite Systems (GNSS) and Very Long Baseline Interferometry (VLBI). In this paper, we established site-wise empirical Wuhan University Tropospheric Model (WTM) by using 10-year (2011–2020) monthly mean 5-year (2016–2020) hourly ERA5 reanalysis data, where Zenith Path Delay (ZPD), mapping function, horizontal gradient well meteorological parameters are provided at 1583 specific stations with additionally considering diurnal semi-diurnal variations. function from WTM were evaluated 524 globally distributed GNSS during year 2020 compared latest grid-wise (1° × 1°) Pressure Temperature 3 (GPT3) model. significant improvements of to GPT3 found terrain relief, maximal accuracy reached 12.8 14.71 mm. ZPD functions two models also validated 31 Multi-GNSS Experiment (MGEX) spanning BeiDou System (BDS) Precise Point Positioning (PPP). vertical coordinate ZTD difference biases between PPP schemes adopted found, largest −1.78 0.87