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    湖北省分钟级雨强时空分布特征

    Analysis of temporal and spatial distribution characteristics of minutely rainfall in Hubei province

    • 摘要: 利用2019—2022年3—9月湖北省2523个区域站和国家站逐分钟雨量资料分析了湖北省6 min雨强时空分布特征,简要总结了产生极端雨强的天气系统及大气环境背景,主要结论如下:全省平均6 min雨强最大值为14 mm,西部山区6 min雨强平均值略小于东部。鄂西南分钟级极端降水的数值较大,但出现频次较少,鄂东地区分钟级雨强大且出现频次多。3—5月,鄂东南以及江汉平原区域为降水高发地区,鄂西北虽然分钟级强降水的频次不多,但会出现极端的分钟级雨强,致灾风险较高;6—7月强降水频次明显增多且分布范围较广,6 mm以上降水高频中心位于鄂东北,与梅雨期的低空急流和大别山地形的相互作用有关;8—9月,3 mm以上雨强多发于山区平原过渡带的宜昌、恩施以及大别山南部黄冈东部。6 min雨强频次分布存在明显的日变化,峰值集中在午后至前半夜,以16:00—18:00频次最高,峰值时段对应午后热对流以及夜间急流加强时段。月极值雨强出现时高空天气系统分为三种类型,高空低槽型占一半以上,槽后西北气流型次之,副高型最少。极端分钟级雨强的产生与中小尺度系统的发展演变过程密切相关。

       

      Abstract: Based on the minutely rainfall data of 2523 surface automatic observation stations from March to September in Hubei province from 2019 to 2022, the spatial and temporal distribution characteristics of 6-min rainfall, as well as the synoptic systems and environment characteristics of the extreme 6-min rainfall were analyzed. The results indicate that: the provincial average of the maximum of 6-min rainfall is 14 mm, and the western average of 6-min rainfall is less than the eastern. The extreme 6-min rainfall in southwest of Hubei is quite large with lower frequency, while the minutely rainfall in eastern of Hubei is large and with higher frequency. From March to May, the frequency of rainfall in Jianghan Plain and southeastern Hubei is high, while in northwestern Hubei which is lower but extreme thus leading a high risk of disaster. From June to July, the frequency of heavy rainfall is obvious higher and more extended. The high frequency center of rainfall larger than 6 mm locates at northeastern Hubei, which is related to the interaction between the low-level jet during Meiyu and the terrain of Dabie Mountains. From August to September, the rainfall lager than 3 mm happens more often in Enshi and Yichang located in the transition zone between plain and mountain, and in eastern Huanggang located the south of Dabie Mountains. The frequency of 6-min rainfall shows obvious diurnal variations, and the high period occurs from afternoon to midnight, with the peak from 16:00 BT to 18:00 BT. The high frequency period relates to the afternoon thermal convection and the nocturnal intensifying low-level jet. The synoptic systems of maximum 6-min rainfall in each month divided into 3 types, in which the upper-level trough type occupying more than half, followed by the northwest flow behind trough type and subtropical high type. The extreme minutely precipitation is closely related to the evolution of mesoscale synoptic system.

       

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