Estimation Scheme and Preliminary Application of Dew Point Temperature Profile of Ground-based Micro wave Radiometer
In view of the uncertainty of direct and indirect empirical formulas for dew point tempera-ture,this paper discusses the applicability of dew point temperature estimation scheme based on charac-teristics of ground-based microwave radiometer data and its preliminary application.The purpose is to pro-vide the basic physical dew point temperature with high spatial-temporal resolution for forecasters to deter-mine the degree of atmospheric saturation,and to serve severe convective weather warning.The results show that:(1)Relative humidity is the sensitive factor for the difference between the direct and indirect calculation formula of dew point temperature.The dew point temperature estimation scheme based on LV2 data of ground-based microwave radiometer can be as follows:when the relative humidity is less than 50％,the direct calculation formula is used;when the relative humidity is between 50％and 99％,the indirect calculation formula is used;when the relative humidity is 100％(saturation),the temperature is warmer(colder)than-48.75 ℃,the indirect(direct)calculation formula is used.(2)The precision of dew point temperature products estimated by ground-based microwave radiometer keeps high correlation of temperature products,improving the system deviation to a large extent,but the dispersion degree is slightly expanded.Among them,the correlation coefficient changes from 0.99 to 0.98,reduced by 0.01 slightly;the systematic deviation changes from-3.18 ℃ to-0.98 ℃,reduced by 2.2 ℃;the mean deviation changes from 4.92 ℃ to 5.26 ℃,increased by 0.34 ℃.(3)Compared to relative humidity,the estimated dew point difference is more"sensitive"to the high humidity area(the relative humidity is more than 70％),and can well"outline"the saturation state and characteristic structure of water vapor in clouds and other hydrometeors.This is helpful for users to visually see the saturated area,unsaturated area and the transition area between them.Combined with ground-based microwave radiometer measure-ment products,the dew point temperature estimation scheme can monitor the vertical structure character-istics of hydrometeors before,during and after the occurrence of severe convective weather,which is a good reference for making weather forecast and early warning.The lead time of early warning can reach 0.5-1.0 h,and that of the end of precipitation forecast can reach 10 min.
microwave radiometerdew point temperatureestimation schemesevere convective weather
万方数据
维普
