Abstract:
Weighted mean temperature (
Tm) is a critical parameter in global navigation satellite system technology to retrieve precipitable water vapor. In this paper, the products from the European Center for Medium-Range Weather Forecasts (ECMWF) are used to analyze the distribution trait of
Tm along the vertical direction, and to establish a new global
Tm model. The ECMWF and radiosonde data are used to validate this newly built model, and an existing high-accuracy
Tm model is employed for comparison. The results show that
Tm has nonlinear variation trait along the vertical direction, and this trait is specifically apparent in the high-latitude regions, especially in the polar areas. When tested with the ECMWF and the radiosonde data, the root mean square (RMS) of the newly built model are 3.84 K and 4.36 K, respectively, achieving accuracy improvements of 27% and 20% compared to the existing model. The correction performance for
Tm along the vertical direction is increased noticeably and the
Tm profile calculated by the model proposed in this paper is much closer to the reference.