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中国南方极端降水的不同变化特征研究

Different characteristics of extreme precipitation in southern China

  • 摘要: 利用国家气象科学数据中心的中国南方七省1961—2020年206个气象观测站点的逐日降水资料,采用百分位法提取20时—08时(北京时,下同;夜间)、08时—20时(白昼)、20时—20时(全天)三个时段的95%分位极端降水,分析了60 a中国南方极端降水量及其频次、极端降水最早开始时间、最晚结束时间的时空变化特征。结果表明:(1) 夜间、白昼及全天极端降水阈值的空间分布特征比较相似,夜间极端降水量大于白昼。(2) 中国南方极端降水量及其发生频次整体的长期变化均呈显著增加趋势。夜间、白昼极端降水量及其频次呈增加趋势的站点均超过70%;全天的极端降水量及其频次也有近80%的站点呈增加趋势。(3) 中国南方极端降水的空间分布不均匀,并有昼夜差异。南方年平均极端降水量高值区在两广的偏南地区,夜间年平均极端降水量大于白昼年平均极端降水量;年平均极端降水频次大值区分布与极端降水量明显不同,全天和白昼极端降水频次高值区大多位于南方地区的中部和东部,夜间极端降水频次高值区多位于南方的西北部。(4) 中国南方一年中极端降水从开始到结束的发生时间段有不断延长的趋势。夜间、白昼极端降水开始时间提前趋势和结束时间延后趋势的站点均超过60%;全天极端降水开始时间提前趋势和结束时间延后趋势的站点均超过67%,总体是开始时间平均每10 a提前2 d、结束时间平均每10 a延后近2 d。南方中部地区极端降水开始时间最早,广东西南部、广西和贵州西部开始时间最晚;极端降水结束时间江西北部最早,浙江东部最晚。

     

    Abstract: Based on the daily precipitation data of 206 stations in seven provinces of southern China from 1961 to 2020, the 95th percentile extreme precipitation of 20:00 BT-08:00 BT (nighttime), 08:00 BT-20:00 BT (daytime) and 20:00 BT- 20:00 BT (all-day) was extracted by percentile method, the temporal and spatial characteristics of 60 years' extreme precipitation, frequency, the earliest start time and the latest end time are analyzed. The results are as follows. (1) The spatial distribution characteristics of night, day and all-day extreme precipitation thresholds were similar, and the extreme precipitation at night was larger than that at day. (2) The long-term change of extreme precipitation and frequency in southern China are both increasing significantly. More than 70% of the stations with nighttime and daytime extreme precipitation and frequency are increasing; and nearly 80% of the stations with all-day extreme precipitation and frequency are also increasing. (3) The spatial distribution of extreme precipitation in southern China is uneven and varies between day and night.The high value area of the annual mean extreme precipitation in the south is in the southern part of Guangdong and Guangxi, the annual average extreme precipitation at night is larger than that at daytime; the large value distribution of the annual average extreme precipitation frequency is obviously different from that of extreme precipitation, high frequency area of extreme precipitation of daytime and all-day are located in the central and eastern parts of the Southern China, most of the regions with high frequency of night extreme precipitation at night are located in the northwest of the southern China. (4) The time period of extreme precipitation from beginning to end in southern China is lengthening. More than 60 percent of the stations had an earlier start and later end time trend for both nighttime and daytime extreme precipitation, and more than 67 percent had an earlier start and later end time trend for all-day extreme precipitation, overall, the start time was 2 days earlier on average in 10 years, and the end time was 2 days later on average in 10 years. The onset time of extreme precipitation is the earliest in the central part of South China, and the latest in the southwestern part of Guangdong and the western part of Guangxi and Guizhou; the end time of extreme precipitation is earliest in north Jiangxi and latest in east Zhejiang.

     

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