Region-Specific and Weather-Dependent Characteristics of the Relation between GNSS-Weighted Mean Temperature and Surface Temperature over China

Weighted mean temperature of the atmosphere, Tm, is a key parameter for retrieving precipitable water vapor from Global Navigation Satellite System observations. It commonly estimated by linear model that relates to surface Ts. However, relationship between Tm and Ts associated with geographic regions affected weather. To better estimate over China, we analyzed region-specific weather-dependent characteristics this using 860,054 radiosonde profiles 88 Chinese stations 2005 2018. The slope coefficients site-specific models are 0.35~0.95, which generally reduce northeast southwest. Over southwest coefficient changes drastically, while northwest, it shows little variation. We developed Ts∼Tm data rainless days as well rainy each station. At half stations, mostly located in west north differences rainy-day rainless-day significant larger than 0.5% (1%) (maximal) relative bias. regression precisions higher averagely 28% stations. Radiosonde satisfying Tm−Ts>10 K Ts−Tm>30 most deviate models. Results suggest former situation related low (<270 K), striking humidity inversions below 800 hPa, latter high (>280 K) distinct inversion above 600 hPa.