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2008—2017年四川省突发性山地暴雨事件的演变特征

Evolution characteristics of sudden mountain rainstorm events in Sichuan Province from 2008 to 2017

  • 摘要: 突发性山地暴雨诱发的山洪、滑坡、泥石流等是我国西南山区重大自然灾害。本文利用2008—2017年国家站10 a的小时降水量数据,对四川省突发性山地暴雨事件开展统计特征分析。结果表明:(1)2008—2017年10 a间四川省共出现了979次突发性山地暴雨事件,平均每年约98次,大多数地区出现5次以上,突发性暴雨事件主要发生在四川盆地及其东部、南部山区、西部山区,西部山区频次远远大于东部山区,与地形影响密切相关。(2)突发性山地暴雨事件从4月开始增多,6—7月显著增长,7月之后渐渐减少;夜间多于白天,事件日变化的高频次先从四川西部山区下午16时开始,到深夜转为东部山区最高,表现出强降水有一个从西向东发展传播的过程。(3)突发性山地暴雨事件持续时间大多集中在3~12 h,平均持续时间6月、7月和9月较长,而5月和8月较短,平均持续时间东部山区明显比西部山区长。(4)突发性山地暴雨事件年平均累计雨量在80~120 mm之间,且7月最多,8月次之,5月和9月最小。2015年突发性山地暴雨事件频次最少,但年平均累计雨量最多,说明2015年突发性暴雨强度最大。

     

    Abstract: The secondary disasters such as flash floods, landslides and debris flows induced by sudden mountain rainstorm are major natural disasters in mountain areas of China. In this paper, the statistical characteristics of sudden mountain rainstorm events in Sichuan Province are analyzed by using the 10 year hourly precipitation data of national stations from 2008 to 2017. The results are as following: (1) During the 10 years from 2008 to 2017, there were 979 sudden mountain rainstorm events in Sichuan Province, with an average of 98 events per year. More than 5 sudden rainstorm events occurred in most areas. Sudden rainstorm events mainly occur in the Sichuan Basin and its eastern and southern mountainous areas, and the frequency of sudden rainstorm events in the western mountainous areas is far higher than that in the eastern mountainous areas, which indicates that it is closely related to the terrain. (2) The sudden rainstorm events increased from April, increased by leaps and bounds from June to July, and gradually decreased after July. The sudden rainstorm events at night is more than that in the daytime. The high-frequency distribution of sudden rainstorm events starts at 16:00 pm. in the western mountainous area of Sichuan Province, and turns to the highest in the eastern mountainous area at midnight, which shows that there is a process of development and propagation of heavy rainfall from west to east. (3) The duration of mountain sudden rainstorm events is mostly concentrated in 3~12h, and the average duration is longer in June, July and September, but shorter in May and August. (4) The annual average rainfall of sudden mountain rainstorm events ranges from 80 mm to 120 mm. The accumulated rainfall is the largest in July, followed by August, and the smallest in May and September. In 2015, the frequency of sudden mountain rainstorm events was the least, but the annual average accumulated rainfall was the most, indicating that the intensity of sudden rainstorm was the largest in 2015.

     

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