摘要
选取2015—2017年4—6月发生在广东地区的20个暖区暴雨个例,利用GFS 0.5°×0.5°预报场资料,分析了集合动力因子在华南暖区暴雨中的分布特征。研究结果表明:(1)在广东省的四类主要暖区暴雨中,锋前低槽暴雨中各集合动力因子和累积降水的相关性最高,其次是西南急流暴雨,而回流暴雨中的相关性最差。锋前低槽暴雨与回流暴雨有共同的相关性较好的集合动力因子,高空槽和副热带急流暴雨与西南急流暴雨也有共同的相关性较好的集合动力因子。(2)选取各类暖区暴雨中对降水表征最好的集合动力因子分别构建了3个量级的权重指数(量级分别为10-3、10-1和102),发现各量级的权重指数随着降水量级的增大而增大,说明权重指数对分析判断不同量级的降水具有很好的指示作用。(3)采用各量级权重指数的中位数作为判断降水等级的阈值,并利用3个量级的权重指数可以综合判断降水的强度等级,这为降水的量级预报提供了一个客观化指标。这些结果进一步提高了集合动力因子在华南暖区暴雨预报中的实际应用能力。
In this paper,20 cases of the prefrontal torrential rain in Guangdong Province from April to June of 2015-2017 were selected,and the distribution characteristics of ensemble dynamic factors of the warm-sector torrential rain were analyzed by using the GFS 0.5°×0.5°data.The results are as follows.(1)Among the four types of warm-sector torrential rain in Guangdong Province,the correlation between the ensemble dynamic factors and the accumulated precipitation is the highest in the prefrontal trough torrential rain,followed by the southwest jet torrential rain and the lowest correlation is with the backflow torrential rain.There are common ensemble dynamic factors between the prefrontal trough and the backflow torrential rain,and also between the high-level trough and subtropical jet torrential rain and southwest jet stream torrential rain.(2)Three orders of magnitude weighting index are constructed by different ensemble dynamic factors which are the best representation of precipitation in various warm-sector torrential rains.The index(magnitude is 10-3,10-1 and 102 respectively)is found to be increasing with the increase of precipitation level,which indicates that the index has a good indication for judging the precipitation intensity.(3)The median of each magnitude index is used as the threshold to judge the precipitation intensity,providing an objective norm for the quantity forecast of precipitation.These results further promote the practical application of ensemble dynamic factors in the prediction of warm-sector torrential rain in South China.
作者
苏冉
廖菲
齐彦斌
SU Ran;LIAO Fei;QI Yanbin(Guangzhou Meteorological Observatory,Guangzhou 511430;Weather Modification Office of Jilin Province,Changchun 130062)
出处
《气象》
CSCD
北大核心
2019年第11期1517-1526,共10页
Meteorological Monthly
基金
广东省自然科学基金项目(2019A1515011813)
国家自然科学基金项目(41775140)
广州市科技计划项目(907158342066)
广东省气象局科研项目(GRMC2017Q12)和广东省气象局“地域频发性强降水(‘雨窝’)”项目共同资助
关键词
动力因子
暖区暴雨
阈值
dynamic factor
warm-sector torrential rain
threshold
