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气象:2020,46(11):1405-1414
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2020年6—7月长江中下游地区梅汛期强降水的极端性特征
张芳华,陈涛,张芳,沈晓琳,蓝渝
(国家气象中心,北京 100081;中国气象局-河海大学水文气象研究联合实验室,北京 100081)
Extreme Features of Severe Precipitation in Meiyu Period over the Middle and Lower Reaches of Yangtze River Basin in June-July 2020
ZHANG Fanghua,CHEN Tao,ZHANG Fang,SHEN Xiaolin,LAN Yu
(National Meteorological Centre, Beijing 100081;CMA-HHU Joint Laboratory for Hydrometeorological Studies, Beijing 100081)
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投稿时间:2020-08-07    修订日期:2020-09-02
中文摘要: 2020年6—7月长江中下游地区出现了极为严重的暴雨洪涝。基于国家站长时段逐日降水资料、国家站和区域自动站小时降水资料等分析了强降水的极端性特征。长江中下游地区降水异常偏多的范围明显大于1998年和2016年同期,仅次于1954年。大别山区、皖南山区和鄂西南山区是三个雨量大值中心,最大累计降雨量均在1 500 mm以上。降水的异常偏多与强降水长时间维持在长江中下游地区密切相关。2020年长江中下游梅雨期历时52 d,较常年偏多23 d,且是1961年以来唯一一年6—7月逐旬降水均偏多的年份。不同等级雨日的分析表明,该年中雨、大雨、暴雨、大暴雨及以上站次均为1961年以来同期最多,后三种等级偏多更为显著。强降水的极端性同样体现在小时尺度的短历时降水中,2020年6—7月长江中下游地区出现大于等于20和50 mm·h-1短时强降水的累计站日数分别为1 612和100站日,均列1981年以来的同期第一位;强降水中心的黄山、祁门、岳西和鹤峰站小时降水超过20 mm的时次数是常年同期的2~4倍,各自前43、21、19和27次最强小时降水累加即超过常年6—7月累计降水量。上述结果表明,2020年6—7月长江中下游地区梅汛期强降水在总雨量、持续时长及雨强等方面均具有明显的极端性特征。
Abstract:Severe flood occurred in the middle and lower reaches of the Yangtze River Basin (MLYRB) in June-July 2020 (JJ2020). In this paper, the extreme features of the severe flood are analyzed based on the daily precipitation data from national stations since 1951 and the hourly observations from national and regional stations in JJ2020. The range of anomalous precipitation (anomaly percentage more than 50% or 100%) in MYLRB and the total amount are significantly larger than those in 1998 and 2016, ranked the second in recent 70 years following 1954. There are three rainfall large-value centers with maximal accumulated precipitation exceeding 1 500 mm, which refer to Dabie Mountain Area, southern Anhui and southwestern Hubei. The anomalous-precipitation-caused flood is closely related to the extreme long-term persistence of Meiyu in MLYRB. The Meiyu period in 2020 lasts for 52 days, 23 days more than the climatology. Moreover, in JJ2020, positive precipitation anomaly exists in each dekad, which has never been experienced before since 1961, reflecting the extreme features of the flood. The analysis of rain days of different grades shows that total stations having received moderate rain (10-24.9 mm·d-1), heavy rain (25-49.9 mm·d-1), torrential rain (50-99.9 mm·d-1) and severe torrential rain (≥ 100 mm·d-1) in JJ2020 are the most since 1961, especially the severe precipitations in the last three grades are more significant. The extremity of the severe precipitation can also be found in the short-duration heavy rain processes. In JJ2020, the accumulated station number and days with hourly precipitation over 20 mm and 50 mm are respectively 1612 and 100, both of which are the highest since 1981. At the four stations with total precipitation exceeding 1 500 mm, frequencies of hourly precipitation more than 20 mm are 2-4 times that of the same period in normal years. Accumulation of the first 43, 21, 19 and 27 heaviest hourly precipitation at the four stations exceeds their seasonal averages, respectively. The above results suggest that the significant extremity of the JJ2020 severe precipitation in Meiyu period in MLYRB exists in the total rainfall, the duration and the short-term intensity of severe precipitation.
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基金项目:中国气象局暴雨预报专家创新团队专项(CMACXTD002-3)和国家科技支撑计划(2015BAC03B04)共同资助
引用文本:
张芳华,陈涛,张芳,沈晓琳,蓝渝,2020.2020年6—7月长江中下游地区梅汛期强降水的极端性特征[J].气象,46(11):1405-1414.
ZHANG Fanghua,CHEN Tao,ZHANG Fang,SHEN Xiaolin,LAN Yu,2020.Extreme Features of Severe Precipitation in Meiyu Period over the Middle and Lower Reaches of Yangtze River Basin in June-July 2020[J].Meteor Mon,46(11):1405-1414.