微波辐射计反演产品评价

利用北京南郊探空资料,对从美国进口的微波辐射计近3年反演资料,从总体平均、早晚平均、平均年变化以及不同天空状况4个方面进行分析、评价,以了解该设备的性能和产品特点。结果表明:①温度均方根误差从近地面到5000 m,误差逐渐增大,5000 m以上又逐渐减小。相对误差总体平均不到0.2,且均为正,表明仪器反演的温度比探空的偏高。②湿度从近地面到3000 m误差逐渐增大,3000 m以上逐渐减小。总体平均相对湿度的误差均为正,表明仪器反演出的相对湿度比探空的偏高。③从温、湿度误差的早晚对比看,20:00的误差相对比08:00小。④从不同天空状况看,温度碧空、多云间晴效果较好,多云转阴、阴天效果较差;湿度多云转阴、阴天效果较好。⑤从温、湿度误差的年变化来看,温度均方根误差1500 m以下年内变化幅度较小,1500 m以上变化幅度较大,呈现出8月误差最小,3、4月最大;相对湿度的均方根误差在1500 m以下年内变化比较相似,1500 m以上脉动变化比较大。

Evaluation and Analysis of Retrieval Products of Ground Based Microwave Radiometer

By means of the radiosonde data and the three-year data of the microwave radiometer in Beijing in recent 3 years,from the aspects of total average,daily change,annual mean change,and different sky status,etc.,the evaluation and analysis of the retrieval products are made.The results indicate：（1） The root-mean-square error of temperature increased from surface to 5000 meters and decreased above 5000 meters gradually.The overall average relative error was less than 0.2 ℃ with a positive value,which shows that the retrieved temperature was higher than that from the radiosondes.（2） The root-mean-square error of humidity increased from surface to 3000 meters and decreased above 3000 meters,and the overall average relative error was positive,which shows that the retrieved humidity was also higher than that from the radiosondes.（3） The error at 20：00 was smaller than that at 08：00.（4） The temperature error was relatively small while it was clear and clear to cloudy,and bigger while overcast or cloudy to overcast.The humidity error in overcast and cloudy to overcast weather was small.（5） There was a small annual change range in the root-mean-square error of temperature under 1500 m,but big above 1500 m,smallest in August,biggest in March and April;the root-mean-square error of relative humidity had a similar change pattern as above under 1500 m,and changed more obviously above 1500 m.