GSI同化GPS可降水量对四川盆地不同类型降水模拟影响  

The impact of assimilation of GPS precipitable water vapor in GSI on the simulation of different precipitation types in Sichuan Basin

作　　者：王成鑫 杨晓丹[2] 师义成 茅家华 赵鲁强[2] WANG Chengxin;YANG Xiaodan;SHI Yicheng;MAO Jiahua;ZHAO Luqiang(Beijing Presky Technology Company Limited,Beijing 100195,China;Public Weather Service Center,China Meteorological Administration,Beijing 100081,China;China Three Gorges Construction Engineering Corporation,Chengdu 610041,China;Zhejiang University of Water Resources and Electric Power,Hangzhou 310002,China)

机构地区：[1]北京弘象科技有限公司,北京100195 [2]中国气象局公共气象服务中心,北京100081 [3]中国三峡建工集团有限公司,成都610041 [4]浙江水利水电学院,杭州310002

出　　处：《科技导报》2022年第13期96-106,共11页Science & Technology Review

基　　金：国家重点研发计划项目(2018YFC1505503-1);国家自然科学基金青年基金项目(41905048);金沙江下游梯级水电站气象预报关键技术研究及系统建设项目(JG/20015B)。

摘　　要：选取四川盆地金沙江下游对流性降水个例(记为CR_2013)和稳定性降水个例(记为SR_2015),利用格点统计插值分析系统(GSI)同化全球定位系统(GPS)大气可降水量(PWV)资料,并结合天气研究与预报模式(WRF)对2次不同类型降水过程的初始场和模拟降水进行同化效果对比分析。结果表明,降水发生前,四川盆地已有较多水汽积聚,水汽分布东多西少,2个降水个例的强降水中心分别位于南侧和北侧的GPS水汽梯度带上。同化GPSPWV资料在改善初始湿度场的同时对初始温度场和风场也有不同程度的改善。控制实验的降水大小和分布总体都与实况较相似,但存在局部模拟偏强的情况。同化GPS-PWV对降水模拟的改进作用明显:CR_2013模拟的强降水中心范围与实况更接近,而SR_2015则明显减弱了虚假降水中心的强度和范围。降水调整最显著的区域与实况降水中心一致,都在GPS水汽梯度带上。同化GPS-PWV能持续影响模拟的累积降水,对流性降水调整幅度要高于稳定性降水。In order to evaluate the impacts of assimilation of GPS(global position system)-PWV(precipitable water vapor)on the initial field and simulation of different precipitation types in Sichuan Basin,several control tests and assimilation experiments were performed using GSI(gridpoint statistical interpolation)and WRF(weather research and forecasting)model.Two cases,namely CR_2013 and SR_2015,representing the processes of convective precipitation and stable precipitation,respectively were analyzed.The results showed that a great amount of water vapor had accumulated in Sichuan Basin before the occurrence of rain,with the amount in the east being more than that in the west.The rainstorm centers of the two cases were located at the southern and northern gradient zones of GPS water vapor,respectively.The assimilation of GPS-PWV not only improved the humidity field but also ameliorated temperature and wind field to some extent.Although the locations and intensities of simulated precipitation in the control tests were generally similar to the observed precipitation,there was stronger simulated precipitation in small areas.The assimilation of GPS-PWV significantly improved the simulation of precipitation.The range of simulated rainstorm centers of CR_2013 was closer to the observation,while the simulation of SR_2015 significantly weakened the intensity and range of the fake rainstorm centers.The most significant adjustment was located at the gradient zones of GPS water vapor,which was consistent with the observed rainstorm center.The assimilation of GPS-PWV continuously influenced the simulated accumulated precipitation,and the adjustment range of convective precipitation was higher than that of stable precipitation.

关 键 词：GSI GPS-PWV WRF 三维变分同化 水汽梯度 

分 类 号：P228.4[天文地球—大地测量学与测量工程] P412[天文地球—测绘科学与技术]