Taking short-duration heavy rainfall and convective wind gusts as examples, the present study examined the characteristics of radar reflectivity and several convective parameters. We analyzed nowcasting techniques by ...Taking short-duration heavy rainfall and convective wind gusts as examples, the present study examined the characteristics of radar reflectivity and several convective parameters. We analyzed nowcasting techniques by integrating a high-resolution numerical weather prediction model with these convective parameters. Based on the CMA-GD 1-km model and its assimilation system, we conducted repeated tests on radar reflectivity data assimilation and analyzed their impact on nowcasting accuracy. Based on these analyses, we proposed a method to improve model forecasts using the useful indicative information provided by high-frequency radar reflectivity data and convective parameters. The improved method was applied to the CMA-GD 1-km model for nowcasting tests. Evaluations from batch tests and case analysis show that the proposed method significantly reduced the model's false alarm rates and improved its nowcasting performance.展开更多
This paper describes an analogue-based method for producing strong convection forecasts with conventional outputs from numerical models.The method takes advantage of the good performance of numerical models in predict...This paper describes an analogue-based method for producing strong convection forecasts with conventional outputs from numerical models.The method takes advantage of the good performance of numerical models in predicting synoptic-scale weather situations.It calculates the convective parameters as predictors to detect the favorable-occurrence environment of strong convections.Times in the past when the forecast parameters are most similar to those forecast at the current time are identified by searching a large historical numerical dataset.The observed strong convection situations corresponding to those most similar times are then used to form strong convection forecasts for the current time.The method is applied as a postprocess of the NCEP Global Forecast System(GFS)model.The historical dataset in which the analogous situations are sought comprises two years of summer(June–September)GFS 6-to 48-h forecasts.The strong convection forecast is then generated every 6 h over most regions of China,provided the availability of strong convection observations.The results show that the method performs well in predicting strong convections in different regions of China.Through comparison with another postprocessing strong convection forecast method,it is shown that the convective-parameter threshold problem can be solved by employing the analogy method,which considers the local historical conditions of strong convection occurrence.展开更多
基金Key-Area Research and Development Program of Guangdong (2020B1111200001)National Natural Science Foundation of China (42230105, U2142213, 42175167)。
文摘Taking short-duration heavy rainfall and convective wind gusts as examples, the present study examined the characteristics of radar reflectivity and several convective parameters. We analyzed nowcasting techniques by integrating a high-resolution numerical weather prediction model with these convective parameters. Based on the CMA-GD 1-km model and its assimilation system, we conducted repeated tests on radar reflectivity data assimilation and analyzed their impact on nowcasting accuracy. Based on these analyses, we proposed a method to improve model forecasts using the useful indicative information provided by high-frequency radar reflectivity data and convective parameters. The improved method was applied to the CMA-GD 1-km model for nowcasting tests. Evaluations from batch tests and case analysis show that the proposed method significantly reduced the model's false alarm rates and improved its nowcasting performance.
基金This study was supported by the Strategic Pilot Science and Technology Special Program of the Chinese Academy of Sciences[grant number XDA17010105]the Special Scientifific Research Fund of the Meteorological Public Welfare of the Ministry of Sciences and Technology[grant number GYHY201406002]the National Natural Science Foundation of China[grant numbers 41575065,41875056 and 4177510].
文摘This paper describes an analogue-based method for producing strong convection forecasts with conventional outputs from numerical models.The method takes advantage of the good performance of numerical models in predicting synoptic-scale weather situations.It calculates the convective parameters as predictors to detect the favorable-occurrence environment of strong convections.Times in the past when the forecast parameters are most similar to those forecast at the current time are identified by searching a large historical numerical dataset.The observed strong convection situations corresponding to those most similar times are then used to form strong convection forecasts for the current time.The method is applied as a postprocess of the NCEP Global Forecast System(GFS)model.The historical dataset in which the analogous situations are sought comprises two years of summer(June–September)GFS 6-to 48-h forecasts.The strong convection forecast is then generated every 6 h over most regions of China,provided the availability of strong convection observations.The results show that the method performs well in predicting strong convections in different regions of China.Through comparison with another postprocessing strong convection forecast method,it is shown that the convective-parameter threshold problem can be solved by employing the analogy method,which considers the local historical conditions of strong convection occurrence.
