重庆短时强降水时空特征分析

The Characteristics of Short-Time Strong Precipitation Distribution

  • 摘要: 利用2008—2018年地面自动站逐小时降水资料,统计分析重庆短时强降水的时空分布特征,结果表明:1)重庆短时强降水高频中心在西部合川,东北部开州、巫溪和云阳,东南部酉阳、秀山地区,均毗邻陡峭山脉,地形抬升和特殊地形对降水有增幅作用;2)短时强降水主要集中在6—8月,7月为峰值期,20~30 mm/h和30~50 mm/h站次月际呈反位相变化,前者先降后增,后者呈先增后降;日内短时强降水主高峰在凌晨到早间(00—08时),峰值在03—05时,次高峰在15—18时,主高峰峰值明显强于次高峰;3)西南低涡背景下,重庆西部的高频中心远强于东南部酉阳、黔江次中心,西南低涡对西部地区短时强降水影响更明显,高频月份在6月;对短时强降水量的贡献量,以西部和主城最大,其次是西南部、中部和东部地区,东北部城口、巫溪和东南部秀山贡献最小;4)不同海拔短时强降水频次分布与站点数密切相关,海拔200~800 m的短时强降水频次占总频次的83%,且出现了雨强极值最大值,随后,频次和雨强极值呈明显下降趋势。

     

    Abstract: Based on conventional ground automatic station observation data from 2008 to 2018. The result revealed the characteristics of short-time strong precipitation in Chongqing. (1) The high-frequency center of short-term heavy precipitations in Chongqing are local in Hechuan, Kaizhou, Wuxi and Yunyang and Wushan, all of which are adjacent to steep mountains. The orographic uplifting and special terrain have an increasing effect on precipitation. (2) The short-term heavy precipitation is mainly concentrated in June to August, and peaked in July. Monthly numbers of stations with 20-30 mm/h and 30-50 mm/h precipitations show the characteristics of reverse phase changes, the former is increasing first and then decreasing, and the latter vice versa; The main peak period of short-term heavy precipitations was between 00 and 08 BT, and the heaviest precipitation occurs between 3 and 5 o’clock, and the secondary peak period was between 15 and 18 BT. The precipitation intensity of the main peak period was significantly stronger than that of the secondary peak period. (3) Against the background of the southwest vortex, the precipitation intensity of highfrequency center in western Chongqing is much stronger than Youyang and Qianjiang as sub-centers in southeastern Chongqing, so the southwest vortex has a more significant impact on the short-term heavy precipitation in the western region, and June has the highest frequency of precipitation; The contribution of precipitation is the largest in the western and the main city of Chongqing, followed by the southwest, middle and east regions, and the least in Chengkou and Wuxi where the northeastern and Xiushan where the southeastern Chongqing. (4) The frequency distribution of short-term heavy precipitations at different altitudes is closely related to the number of stations. The frequency of short-term heavy precipitation at an altitude of 200-800 m accounts for 83% of the total frequency, and the maximum value of the extreme precipitation intensity also appears in this range. Outside this range, the frequency and the extreme value of precipitation intensity shows a clearly downward trend.

     

/

返回文章
返回