红外云图晴空区导风风矢高度指定方案与检验

在静止卫星红外云图上,用实际大气廓线的响应权重取代标准大气的响应权重,对利用时间序列差分法反演出的晴空区风矢,进行高度重新指定。然后对台风个例高度重新指定前、后的晴空区风矢进行了误差统计检验和分析,最后利用三维中尺度同化系统WRF\|3DVAR进行了敏感性试验。结果表明:利用实际大气廓线的权重响应进行高度指定优于标准热带大气廓线,晴空风矢高度主要分布在600~900 hPa之间;经高度重新指定后各高度层上的晴空区风矢的均方根差和标准差明显减小,风速偏差集中。同化经过高度重新指定的晴空区风矢能够减小台风路径预报误差。因此,对晴空区风矢进行高度重新指定能够改善晴空风矢产品的质量。

Atmospheric Motion Vectors Height Assignment and Verification in Clear\|sky Regions from Infrared Imagery

For their excellent temporal and spatial coverage,Atmospheric motion vectors(AMVs) have dispalyed great application perspective in improving the initial fields and numerical forcasts.In Geostationary Opertional Meteorological Satellite FY\|2E infrared imagery,AMVs in Clear\|sky regions,which have been retrieved by the time difference technique.However,the study on the height assignment of AMVs data in Clear\|sky regions is very lacking.In order to adjust the height of AMVs in Clear\|sky regions,the standard profile is used to compute weight response between Water vapor content and Satellite Infrared Radiation at different heights that is replaced by the practical atmospheric profile.Then statistical test and error analysis to AMVs in Clear\|sky regions is compared before and after height adjustment for Typhoon cases.At last,the Sensitivity experiments is performed in the three\|dimensional meso\|scale assimilation model WRF\|3DVAR.As a result,using the weight response calculated by practical atmospheric profile to determining AMVs height assignment is superior to weight response calculated by standard profile.And the height of AMVs in Clear\|sky regions is distributed in 600~900 hPa;After height assignment,the root\|mean\|square error and standard deviation of AMVs at every level in Clear\|sky regions have decreased apparently.The result of assimilation test confirm that the forcast track error of Typhoon is reduced in 48 hours with the assimilation of AMVs in Clear\|sky regions.Therefore this height assignment can improve the quality of AMVs in Clear\|sky regions.