Bias characterization of ATMS low-level channels under clearsky and cloudy conditions  

作　　者：Qi LI Xiaolei ZOU 

机构地区：[1]Joint Center of Data Assimilation for Research and Application,College of Atmospheric Science,Nanjing University of Information Science and Technology (NUIST),Nanjing 210044,China [2]Earth System Science Interdisciplinary Center (ESSIC),University of Maryland,College Park,MD 20740-3823,USA

出　　处：《Frontiers of Earth Science》2019年第2期277-289,共13页地球科学前沿（英文版）

基　　金：the National Key R&D Program of China (No.2018YFC1507302);the Mathematical Theories and Methods of Data Assimilation supported by the National Natural Science Foundation of China (Grant No.91730304).

摘　　要：The Advanced Technology Microwave Soun? der (ATMS) onboard the Suomi National Polar-Orbiting Partnership satellite is a cross-track scanning instrument containing 22 sounding channels in total.In this study,the bias characteristics of channels 1-6,which could have significant cloud contamination in heavy precipitation,are first analyzed based on the differences between ATMS observations (O) and model simulations (B) under clearsky conditions over oceans.Latitudinal dependencies of the biases of window channels 1-3 are greater than those of channels 4-6.Biases of all nadir-only observations examined in different latitudinal bands[μ1(φ)]are positive and no more than 7.0 K.Biases at higher latitudes are larger.Channels 1-5 have a generally symmetric scan bias pattern [μ2(α)].The global distributions of brightness temperature differences after subtracting the biases,i.e.,O-B-μ1(φ)-μ2(α),for channels 3-6 spatially match the liquid water path distributions.Excluding ice-affected observations,channel 3-6 O-B differences systematically increase as the liquid water path increases under cloudy conditions.Further investigation is needed to apply these findings for ATMS data assimilation under both clear-sky and cloudy conditions.

关 键 词：ATMS O-B clear-sky BIAS characteristics impact of CLOUDS on biases 

分 类 号：P[天文地球]