Research On Precipitation Nowcasting Method Integrating Wind Profiler Radar Data

Based on the study of convective storm structure and its motion mechanism,this paper finds that wind plays an important role in convective motion,and proposes a method to improve linear extrapolation forecast by wind field(WPRN method).The method combines the improved method of the centroid tracking method(ESTITAN method)and the improved cross-correlation method(multi-region TREC method),and integrates the wind profile radar data,and uses the dynamic Z-I relationship method to realize the precipitation nowcasting.This paper draws the following conclusions from the study of wind profile radar data,WPRN method,ESTITAN method and multiregion TREC method: Based on the comparative analysis of wind profile radar horizontal wind data and LAPS and GFS mode reanalysis data,it is found that precipitation weather will cause anomaly of observation data.The horizontal wind data of wind profile radar below 3 km is less affected by precipitation weather.It is necessary to select an appropriate height of wind for extrapolation nowcasting;Wind profiler radar products include vertical wind speed,signal-to-noise ratio and atmospheric refractive index structure constants in the process of precipitation.It is found that when signal-to-noise ratio is greater than 30 dB,precipitation occurs,and all product trends meet the variation of hourly precipitation.With the obvious increase of precipitation development,it has an indication of precipitation;Compared with the prediction results of ESTITAN method,multi-region TREC method and WPRN extrapolation forecast method,the WPRN extrapolation prediction method is obviously superior to the other two methods within 20 min,and the success rate and the adjacent success index are higher.After 20 min,the ESTIATN method is better than the other methods;Comparing the three methods of precipitation nowcasting results,the WPRN extrapolation forecasting method is more consistent with the actual precipitation,which has obvious advantages over the other two methods.The average error of hourly precipitation is at least 0.01mm/h,especially in the precipitation forecast area and quantitative error of rain intensity above 15mm/h,which is the closest to the actual one,and it is more realistic for the prediction of strong convective precipitation.