Analysis On The Application Of Microwave Radiometerin Precipitation Process In Yili

The ground-based microwave radiometer is a new type of meteorological observation instrument, which is applied in remote sensing technology, it can continuously observe the vertical structre of temperature, relactive humidity and water vapor content. Reserchers can obtain data of high spatial ang temporal resolution and make up for the shrtcomings of conventional sounging data. It also becomes a new method for study of detecting water vapor. The water vapor content is an important meteorological parameter, which it is also one of important issues in the meteorology and climatology has been concerned. The amount of water vapor, evolution and transfer characteristics is one of the main factors causing precipitation of Xinjiang. The ground-based microwave radiometer can observe the variation water vapor in 24 consecutive hours and output very precise data of precipitation.It provides reliable technical support means for fine weather forcast and nowcasting.In this paper, we selected the microwave radiometer observed data of 2012 March to 2013 February in Yining and the same period radiosonde data, than analysis the correlation of data detected by the two devices, and discusse the reason of difference of the data after comparing the two groups of data.We focus on the study of veritical distribution of water vapor content and liquid water content detected by microwave radiometer and analyzed the change rule of them, than find out the changes threshold in the process of rainfall. Through the experiments and analysis, the conclusions are as follows:1. The two devices had good correlation in temperature and vapor content, but the relative humidity was poor correlation. In the whole year, the correlation coefficient of temperature is 0.99, the correlation coefficient of water vapor content is 0.868, the correlation coefficient of relative humidity is 0.616, both of which successfully passed the significance level test with credible degree of 0.01.With the comparison of profile, we found that the temperature of microwave radiometer is lower than radiosonde’s above 1700 meters,but more than 2000 meters height,both the relative humidity and water vapor content of microwave radiometer are higher than which measured by radiosonde. The figures measured by microwave radiometer and radiosonde have a maximum difference which appears between 3000 meters ~5000 meters. Two device detections existed system error.The deviation of this two detection methods performance different whether different height or different season. The correlation coefficient of temperature in the four seasons is all above 0.98. In addition to the correlation coefficient of water vapor content of summer is above 0.9, the correlation coefficient of spring, autumn and winter are about 0.85. Besides the humidity correlation conefficient of summer is less than 0.5, the humidity of correlation coefficients of spring, autumn, winter are above 0.6.2. By using and analysing observation data of MP-3000 A ground-based microwave radiometer of seasonal precipitation cases, we found that the precipitable water(PWV) and liquid water content(VIL) of the atmosphere have a good corresponding relation and the same trend in the precipitation process. The result of polynomial equation fitting model of water vapor and liquid water is good, the correlation coefficient are all greater than 0.9. In 6hours before the start of the precipitation, the water vapor content increased slowly that was the water vapor transport process. In the 1hour before precipitation, water vapor content would increase sharply, the increment were between 8.0mm~10.0mm. In 6hours before the start of the precipitation, liquid water remained at a low level figure and had been tiny variation. In the 1hour before precipitation, liquid water content also increased sharply and the increment were between 2.0mm~6.5mm. The changes of temperature, water vapor density and liquid water density in precipitation process are significant. In front of precipitation hours, temperature of each level rises sharply and has a good response with atmospheric precipitation. The water vapor density and liquid water density are increasing sharply below 6000 meters. In one hour after the beginning of precipitation, they will also decline. If the time of precipitation lasts long, the water vapor density and liquid water density will change significantly by increasing and decreasing many times. An hour after rainfall, water vapor density and liquid water density decrease quickly and restore stability. These changes have a good response relationship with precipitation and have a good indication of rainfall.