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

[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.

[发布日期] 2019-01-14

[学科分类] 大气科学

[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