基于雷达产品阈值与闻雷半径的雷暴过程判别

为向雷暴识别、跟踪和临近预报系统提供贴近台站实际的雷达产品阈值,建立基于雷达观测的雷暴日判别算法,利用雷暴人工观测资料和雷达产品数据构建匹配率模型,采用累积距平法识别匹配率拐点来判定阈值和最优闻雷半径,并计算出回波面积阈值.以常德气象观测站为例应用该方法,结果表明:①雷达产品阈值为38.5 dBz,最优闻雷半径达到25...

Identification of Thunderstorm Processes Based on Radar Product Threshold and Hearing-Thunder Radius

To provide radar product thresholds close to the actual for thunderstorm identifying,tracking and nowcasting systems,and to establish the algorithm of thunderstorm day discrimination based on radar observation,the artificial thunderstorm observation and radar data are used to construct the matching rate model,and the cumulative departure method is adopted to identify the matching rate of inflection point to determine the thresholds and the optimal radius of hearing thunders,and the echo area of the threshold is given.Taking the Changde meteorological station as an example,using this method,it is resulted that:(1)The threshold value of radar product is 38.5dBz,and the optimal radius of hearing thunders reaches 25km,which is larger than the radius obtained by comparing the lightning location data with the artificial thunderstorm day.The echo area threshold value is 73km2,and the evaluation indicates that the threshold values are appropriate.(2)The seasonal variation of thunderstorms should be taken into account when using various thresholds and radar data to judge thunderstorm days.The performance is satisfactory in the Changde area from March to August.(3)When using this method,the matching rate model should be constructed based on the single radar or radar mosaic data samples of the long-time series selected according to the historical hearing-thunder locations.