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

作者：Qi LI,Xiaolei ZOU

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.

發文機構：Joint Center of Data Assimilation for Research and Application Earth System Science Interdisciplinary Center （ESSIC）

關鍵詞：ATMSO-Bclear-skyBIAScharacteristicsIMPACTofCLOUDSonbiases

分類號： P[天文地球]