降水对地基微波辐射计反演误差的影响

利用武汉站高时间(3h)、高空间垂直(30m)分辨率探空资料和MP-3000A型地基微波辐射计资料,分析了降水对地基微波辐射计反演误差的影响,并对微波辐射计和探空的要素廓线进行了对比分析。结果表明,降水对两种设备的温度廓线和水汽密度廓线的相关性无明显影响,但对相对湿度廓线的相关性有较为明显的影响,其相关性在有降水时好于无降水时;整体上,微波辐射计的廓线误差在降水时大于无降水时,其温度、相对湿度和水汽密度廓线的平均偏差均值分别在1.0～2.5℃,6%～15%和0.08～1.75g.m-3之间,对应的均方差均值分别在1.3～1.6℃,14%～17%和1.28～1.85 g.m-3之间。另外,将不同高度上同时刻微波辐射计和探空的资料进行点对点对比发现,降水会严重破坏两种资料的正相关性,导致大部分高度上的廓线呈负相关,同时也明显增加了温度和水汽密度的平均偏差和均方差。

Impact of precipitation on the retrieval deviation of ground-based microwave radiometer

Impact of precipitation on the retrieval deviation of ground-based microwave radiometer is analyzed using high temporal resolu-tion （3 h） and high spatial vertical resolution （30 m） radiosonde data and MP-3000A microwave radiometer data of Wuhan station. The result of the compared profiles shows that the precipitation has no obvious affect on the profiles of temperature and vapor density between these two devices. But the correlation of relative humidity between radiosonde data and microwave radiometer data is affected by precipitation obvious-ly, and the correlation is better in precipitating condition. Overall, the system deviations between the radiosonde profile and microwave radi- ometer profile are bigger in precipitating condition. The mean deviations of temperature, relative humidity and water vapor density profile of microwave radiometer are 1.0-2.5 ℃, 6%-15%, 0.08-1.75 g·m^-3 respectively, and the corresponding mean square deviations are 1.3-1.6 ℃, 14%-17%, and 1.28-1.85 g·m^-3 respectively. The comparison between the microwave radiometer data and radiosonde data by point-to-point at different heights and at the same time shows that precipitation affects seriously the positive correlation between the two kinds of the data mentioned above resulting in the negative correlation at most of heights and increasing the mean deviation and mean square deviation of tem- perature and vapor density.