基于插值气压的GPS反演大气可降水量研究

摘要

The meteorological data are obtained by pressure interpolation for the estimation of GPS precipitable water vapor (PWV) due to the lack of meteorological parameters at GPS sites.The pressure interpolation formula based on segmented height difference is derived by analyzing the relationship between the interpolated pressure at the GPS sites and the pressure at the nearby radiosonde (RS) stations,and the relationship between the interpolated pressure of the GPS sites and the height difference between the IGS stations and the nearby radiosonde stations using the standard atmosphere (SA) model.The new pressure interpolation formula has the same accuracy as the SA model,and the former is simple when the height difference is less than 100 m.GPS PWV is derived from the new pressure interpolation formula,Saastamoinen zenith hydrostatic delay (ZHD) model and the local weighted mean temperature of the atmosphere (Tm).By comparing with RS PWV,the results show that the new pressure interpolation model can be used to calculate GPS PWV with no meteorological data at GPS stations which the RMS error between GPS PWV obtained from the pressure interpolation formula based on segmented height difference and RS PWV is 1-3 mm.%为解决GPS反演大气可降水量(PWV)所需的气象参数,通过标准大气(SA)模型分析插值得到了GPS站气压与相邻探空站气压、GPS站与探空站之间高差的关系,及基于分段高差的气压插值公式.该公式与标准大气模型精度相当,且在高差小于100 m时,其计算更为简单.利用新的气压插值公式、Saastamoinen干延迟模型与建立的局地加权平均温度模型,将四个IGS站(BJFS、KUNM、LHAZ和TWTF)提供的对流层天顶延迟转化得到大气可降水量(GPS PWV),与探空大气可降水量(RS PWV)进行对比,结果表明在不同高差条件下基于分段高差的气压插值模型计算得到的GPS PWV与RS PWV差值的均方根误差为1～3mm,说明该气压插值模型可应用于无气象数据的GPS反演PWV.