基于地基GNSS观测数据的贵州高原地区水汽层析精度分析

Accuracy Analysis of Water Vapor Tomography Based onGround-Based GNSS Observation Data in Guizhou Plateau

利用精密单点定位(PPP)技术处理贵州地基GNSS观测数据,获得高精度天顶对流层延迟(ZTD),进而开展水汽反演获得大气可降水量(PWV)产品。基于斜路径可降水量(SWV),使用自适应联合代数重构算法进行三维水汽层析,空间分辨率优于30 km×30 km,时间分辨率为5 min。以无线电探空数据为参考评估ZTD和PWV精度,其RMS分别为3.55 mm和1.03 mm。以ERA5再分析资料为参考评估三维层析精度,无暴雨发生时,三维层析相对误差不超过10%,偏差最大值为1.03 g/m~3。以无线电探空数据为参考评估三维层析精度,层析结果与无线电探空数据的相关系数在0.97以上,具有较好的一致性。贵阳站和威宁站的平均RMS分别优于0.5 g/m~3和1.2 g/m~3。

We use precise point positioning(PPP)technology to process the ground-based GNSS observation data of Guizhou to obtain high-precision zenith tropospheric delay(ZTD),and then carry out the water vapor inversion to obtain precipitable water vapor(PWV).Based on the slant-path water vapor(SWV),we use the adaptive simultaneous iterative reconstruction technique for 3D water vapor tomography,with spatial resolution better than 30 km×30 km,and time resolution of 5 min.The RMS is 3.55 mm and 1.03 mm respectively when the radiosonde data is used as a reference to evaluate the accuracy of ZTD and PWV.Using ERA5 reanalysis data as a reference to evaluate the accuracy of 3D water vapor tomography,the relative error is less than 10%,and the maximum deviation is 1.03 g/m 3 when there is no rainstorm.Using radiosonde data as a reference to evaluate the accuracy of 3D water vapor tomography,the correlation coefficient between tomography results and radiosonde data is above 0.97,with good consistency.The average RMS of Guiyang station and Weining station is better than 0.5 g/m 3 and 1.2 g/m 3 respectively.