Impact of Assimilating AIRS Cloud Cleared Radiances on the Analysis and Forecast of Polar Lows

Ganeshan, Manisha ; McGrath-Spangler, Erica ; Reale, Oreste ; McCarty, Will ; Gelaro, Ronald

关键词: ASSIMILATION;    ATMOSPHERIC INFRARED SOUNDER;    CLOUDS (METEOROLOGY);    CLOUD COVER;    RADIANCE;    FORECASTING;    CYCLONES;    POLAR METEOROLOGY;    TROPICAL STORMS;    ERRORS;    ANOMALOUS TEMPERATURE ZONES;    VORTICES;    ARCTIC REGIONS;    ANTARCTIC REGIONS;    EARTH OBSERVING SYSTEM (EOS);    NASA SPACE PROGRAMS;   

RP-ID  :  GSFC-E-DAA-TN66629

学科分类：大气科学

美国|英语

来源: NASA Technical Reports Server

【 摘 要 】

Previous work by this team (Reale et al. 2018) has found that the current assimilation of AIRS (Atmospheric InfraRed Sounder) radiances on a regularly spaced thinning grid is suboptimal, probably because of horizontal error correlation over meteorologically inactive areas. Moreover, cloud-cleared radiances appear to be a better product than clear-sky radiances, but need to be assimilated at a much lower density globally, because of the higher information content. Specifically: 1. Assimilation of AIRS cloud-cleared radiances at a density of about one quarter of the clear-sky radiances improves global forecast skill; 2. An adaptive thinning strategy assimilating cloud-cleared radiances at reduced density globally except around tropical cyclones (TCs), leads to substantial improvement in the structure and intensity forecast of TCs without damaging global skill.