GSI-3DVAR背景误差协方差水平相关特征尺度对地面自动气象站资料同化的适应性研究  

A study on adaptability of GSI-3DVAR background error covariance horizontal scale for surface observation data assimilation

作　　者：张依鸣 刘玉宝[2,3] 王昊亮[2,3] 孙荣富 樊小伟 ZHANG Yiming;LIU Yubao;WANG Haoliang;SUN Rongfu;FAN Xiaowei(School of Marine Sciences,Nanjing University of Information Science&Technology,Nanjing 210044,China;Key Laboratory for Aerosol-Cloud-Precipitation of China Meteorological Administration,Nanjing University of Information Science&Technology,Nanjing 210044,China;Precision Regional Earth Modeling and Information Center,Nanjing University of Information Science&Technology,Nanjing 210044,China;Jibei Electric Power Grid Limited Co.,State Grid Corporation of China,Beijing 100054,China)

机构地区：[1]南京信息工程大学海洋科学学院,南京210044 [2]南京信息工程大学中国气象局气溶胶与云降水重点开放实验室,南京210044 [3]南京信息工程大学精细化区域地球模拟和信息中心,南京210044 [4]国网冀北电力有限公司,北京100054

出　　处：《气象科学》2023年第3期370-383,共14页Journal of the Meteorological Sciences

基　　金：国家电网冀北电力公司科技项目(520120210003);国家自然科学基金青年基金资助项目(41905097)。

摘　　要：基于华东地区3 km分辨率WRF(Weather Research and Forecasting)模式和高密度地面自动气象站(AWS)观测,研究GSI-3DVAR同化系统的R_(HZSCL)对AWS观测的地面温度和风观测同化的敏感性。结果表明:运用GSI-3DVAR同化地面AWS观测时,R_(HZSCL)的取值较为敏感;选取合适的R_(HZSCL)能有效改进地面分析场精度,相较于背景场地面温度和地面矢量风差(VWD)RMSE均可减小35%以上。当R_(HZSCL)过大会导致温度高、低值中心的影响范围过大,风分析场较为平滑,无法反映出中小尺度环流结构。但R_(HZSCL)过小则会使得温度分析场增加误差,并导致风分析场出现虚假大风。观测密度稀疏化的敏感性试验结果表明,地面温度场及风场所适应的最优R_(HZSCL)皆随着观测密度的增大而相应减小。Based on a 3 km-grid WRF(Weather Research and Forecasting)model and high-density surface Automatic Weather Station(AWS)observations in East China,the sensitivity of R_(HZSCL) of GSI-3DVAR for assimilation of temperature and wind of the surface AWS were studied.Results show that the value of R_(HZSCL) is rather sensitive for assimilating the surface automatic weather station observations by using GSI-3DVAR.With an appropriate R_(HZSCL),an accurate surface temperature and wind analysis can be achieved.The temperature and Wind Vector Difference(VWD)RMSE can be reduced by more than 35%compared to the background fields.However,if R_(HZSCL) is too large,an excessive expansion on the high and low temperature centers occur and the error is increased.For the surface wind analyses,the default R_(HZSCL) in GSI-3DVAR produced overly smooth wind and little mesoscale structures.Furthermore,a too small R_(HZSCL) would cause falsely strong local winds.By carrying out observation data-thinning experiments,it is found that the optimal R_(HZSCL) varies are opposite to different surface temperature and wind observation density.

关 键 词：背景误差协方差 水平相关特征尺度 GSI同化系统 HZSCL 地面自动气象站 

分 类 号：P456.7[天文地球—大气科学及气象学]