两种红外晴空辐射订正方法及其反演大气参数的比较

Comparison of Two Infrared Cloud-Cleared Approaches and Their Respective Sounding Retrieval Products

比较了目前开发的两种红外晴空辐射订正算法:1)匹配的红外和微波探测值融合的算法,如AIRS/AMSU晴空订正算法(大气红外探测器AIRS,先进的微波探测器AMSU);2)匹配的红外成像与探测值融合的算法,如AIRS/MODIS晴空订正算法(中分辨率光谱成像仪MODIS)。结果表明,相对于MODIS的晴空观测值而言,AIRS/MODIS晴空订正算法优于AIRS/AMSU晴空订正算法,而且AIRS/MODIS晴空订正辐射值反演的大气温湿廓线与欧洲中期天气预报中心(ECMWF)的客观分析场更接近;尽管这两种晴空订正算法本质上相当不同,但都是有效且互补的,当微波探测资料不能获得时,融合红外成像仪和探测器资料就成为唯一可靠的、间接使用有云影响的红外观测值的办法。

It is comparied between two infrared cloud-cleared radiance retrieval approaches, i. e. collocated infrared and microwave measurement and collocated infrared imaging and sounding measurement. It is found that AIRS/MODIS cloud-cleared radiance approach perform better than AIRS/AMSU cloud-cleared radiance approach relative to the collocated MODIS clear averaged radiances. The temperature and total precipitable water retrieved by AIRS/MODIS cloud-cleared radiance approach fit well with that objectively analyzed by ECMWF（ European Center of Medium-range Weather Forecasts）. Preliminary results show that the two approaches, though essentially different, are both effective and complementary. When the microwave measurements are unavailable, the synergistic imaging/sounding approach is the only reliable one, which can indirectly use the cloud-contaminated infrared measurements.