基于不同背景场的云内COSMIC掩星资料的偏差分析  

Bias Characteristics of COSMIC RO Data within Clouds Based on Different Background Fields

作　　者：殷延安 杨胜朋[1,2] YIN Yan’an;YANG Shengpeng(Joint Center for Data Assimilation Research and Application,Nanjing University of Information Science and Technology,Nanjing 210044,Jiangsu,China;College of Atmospheric Science,Nanjing University of Information Science and Technology,Nanjing 210044,Jiangsu,China)

机构地区：[1]南京信息工程大学大气科学学院,江苏南京210044 [2]南京信息工程大学资料同化研究与应用联合中心,江苏南京210044

出　　处：《高原气象》2023年第5期1351-1360,共10页Plateau Meteorology

基　　金：国家自然科学基金项目(41875032)。

摘　　要：利用2007-2009年Cloud Sat卫星云廓线雷达(nadir-pointing cloud profiling radar,CPR)资料,气象、电离层和气候卫星联合观测系统(Global Constellation Observing System for Meteorology,Ionosphere,and Climate,COSMIC)掩星资料,分析了不同类型云内COSMIC掩星资料与欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)和美国国家环境预报中心(National Centers for Environmental Prediction,NCEP)分析场之间的折射率偏差特征。COSMIC与ECMWF和NCEP之间的折射率偏差分别用Nbias^(ECMWF)和Nbias^(NCEP)表示。研究发现,Nbias^(ECMWF)在积云、层积云、高积云和高层云中的最大值分别为1.2%、0.2%、0.5%和0.2%,而Nbias^(NCEP)则分别为1.8%、0.5%、0.5%和0.4%。在层积云的对流层下层Nbias^(NCEP)存在较大的负值,而Nbias^(ECMWF)为正值。折射率的正偏差随着液态水含量增加而增加。从全球分布来看,赤道辐合带云量丰富,Nbias^(NCEP)和Nbias^(ECMWF)也存在明显的正偏差,它在空间上和水汽的正偏差以及温度的负偏差高度相关。The Global Constellation Observing System for Meteorology,Ionosphere,and Climate (COSMIC)radio occultation (RO) from 2007 to 2009 were collocated with the Cloud Sat nadir-pointing cloud profiling radar(CPR) in time and space in this study.We investigated the characteristics of fractional refractivity differences between COSMIC RO and the analysis of the European Centre for Medium-Range Weather Forecasts (ECMWF)and the National Centers for Environmental Prediction (NCEP) within the different clouds.Nbias^(ECMWF) and Nbias^(NCEP)indicate the fractional differences of refractivity between COSMIC RO and ECMWF,and COSMICRO and NCEP analysis,respectively.The maximum values of Nbias^(ECMWF) within cumulus,stratocumulus,altocumulus and altostratus are 1.2%,0.2%,0.5%,and 0.2%.The highest values of Nbias^(NCEP)are 1.8%,0.5%,0.5%and 0.4%,respectively.In the lower troposphere,the value of Nbias^(ECMWF) is positive and increases with the liquid water content,whereas the value of Nbias^(NCEP) is negative.From the perspective of global distribution,large positive refractivity differences for both ECMWF and NCEP analyses are shown in the equatorial convergence zone,which is highly correlated with the positive bias of water vapor and the negative bias of temperature in space.

关 键 词：COSMIC掩星 CLOUDSAT 折射率偏差 液态水含量 

分 类 号：P405[天文地球—大气科学及气象学]