Empirical model for mean temperature and assessment of precipitable water vapor derived from GPS

The estimation of Precipitable Water Vapor(PWV)derived from Global Positioning System(GPS)data at the IGS site WUHN is assessed by comparing with PWV obtained from radiosonde data(No.57494)in Wuhan.The applicability of Saastamoinen(SAAS),Hopfield and Black models used for estimating Zenith Hydrostatic Delay(ZHD)and Zenith Wet Delay(ZWD)and different models is verified in the estimation of GPS-derived PWV for the applied area.The experimental results demonstrated that:1)the precision of PWV estimated from Black model used for calculating ZHD(ZHD B)is lower than that of SAAS(ZHD SAAS)model and Hopfield model(ZHD H)with the RMS of 4.16 mm;2)the RMS of PWV estimated from SAAS model used for calculating ZWD(SAAS)is 3.78 mm;3)the well-known Bevis model gives similar accuracy compared with the site-specific models for T m in terms of surface temperature(T s)and surface pressure(P s),which can reach the accuracy inside 1 mm in the GPS-derived PWV estimates.