The Study Of Using Microwave Radiometer TP/WVP-3000Brightness Temperature In Rain Nowcasting

The temperature and water vapor profiling from microwave radiometer have been used in different part of atmospheric research. In order to make full use of the brightness temperature data from microwave radiometer, we analyzed the microwave radiometer TP/WVP-3000brightness temperature data on Taihu location from January-April,2009, and found that, before raining, the brightness temperature in some channels would be increased. The brightness temperature will be used to settle a rain nowcasting model. The main conclusions of the study are as follows:(1) Before setting up the rain forecast model, the accuracy rain sensors on TP/WVP-3000was assessed, making the rain starting time from vaisala WXT520as standard. The results is that the rain time from TP/WVP-3000was not enough precise. The coefficient of correlation between the time from WXT520and TP/WVP-3000is only0.77.(2) According to the biggest difference and the biggest standard difference of brightness temperature between the rain cases and no rain cases, we choose brightness temperature data from channel1,5, and6as the forecast factor using the discrimination analysis to settle the rain nowcasting model. Using the external data to testing this model, the probability of detection was equal to87%, the false alarm ratio is24%, and the not alarm ratio is13%.(3) Make the precipitable water vapor(PWV) and the integrated liquid water path(LWC) as forecast factor to settle12forecast equation at the same time spot of the equations of Tb as factors. The own validation accuracy of any time spot of PWV and LWC equations are lower than that of Tb equations. In other words, Tb as forecast factor can control the algorithm error.