| 摘要: |
| 【目的】为了掌握湖南省资水流域汛期暴雨气候特征，【方法】利用经验正交函数(EOF)分解、全局Moran指数、线性趋势分析法、Mann—Kendall检验分析了湖南省资水流域14个国家气象站1980—2016年汛期（4—9月）暴雨日数、暴雨量、暴雨集中度、暴雨集中期的时空分布与演变特征，基于Γ分布及雨日、无雨日演变的一阶Markov链模型，从理论上计算了流域14个国家气象站汛期30d内出现暴雨的概率。【结果】结果表明：1资水流域汛期年均暴雨日数（暴雨量）空间分布上上游较少，中下游较多，年均暴雨日数（暴雨量）与地形关系密切，迎风坡处的站点年均暴雨日数（暴雨量）较大，背风坡、盆地处的站点其年均暴雨日数（暴雨量）较小；2暴雨日数（暴雨量）EOF分解存在全局型、南北型两种主要模态，以全局偏少出现年份最多；上世纪80年代为暴雨日数（暴雨量）偏少期，90年代以后为偏多期，90年代为显著偏多期，中下游地区偏多特征尤其明显，偏少期时暴雨空间分布具有随机性，偏多期时暴雨空间分布正相关性显著；3流域平均暴雨日数、平均暴雨量均呈增加趋势，其气候增长率分别为0.1d/10a、13.1mm/10a，年际变化中存在明显突变，突变节点在1987年前后；4流域汛期暴雨时间分布上高度集中，平均暴雨集中度高达0.82，暴雨集中期为6月26日，平均暴雨集中度有增加趋势，平均暴雨集中期有提前趋势；5流域各气象站汛期10d内流域暴雨发生概率较低，20d、30d内暴雨发生的平均概率分别为23.1%、32.2%，暴雨中心安化发生概率最高，分别为39.1%、46.0%，汛期30d内暴雨发生概率分布与平均暴雨日数分布类类似，暴雨日数大的站点暴雨发生概率较高。 |
| 关键词: 湖南省；资水流域；暴雨 |
| DOI： |
| 分类号:P467 |
| 基金项目:国家自然科学基金项目（面上项目，重点项目，重大项目） |
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| A study on climatic features of heavy rain over Zishui river basin in Hunan province during flood season |
|
libing
|
|
Yiyang Meteorological Bureau
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| Abstract: |
| 【Objective】In order to have a better understanding of the climatic features of heavy rain over Zishui river basin in Hunan province from 1980 to 2016 during flood season(April to September).【Method】By using of EOF decomposition、Global Moran Index、?Mann-Kendall test,the spatial and temporal evolutionary characteristics of heavy rain over Zishui river basin in Hunan province were studied in the present paper.Probability of heavy rain of each national meteorological observatory were also calculated according to statistical theory.Some useful conclusions were obtained as followed.【Result】(1)Spatial distribution of number days of heavy rain over Zishui river basin is inhomogeneous which is greater in the middle and down stream than the up stream.(2)There are two kinds of typical modes for heavy rainfall under EOF decomposition,namely the whole region,north-south.There are fewer heavy rain and negative Global Moran Index in 1980s.(3)The number days of heavy rain and rainfall both have increasing tendency, the mean value of climatic growth rate are 0.1 day and 13.1 millimeter per 10 years respectively. (4)Heavy rainfall over Zishui river basin is highly concentrated in time,the mean precipitation concentration degree(PCD) of heavy rain is 0.82.The mean precipitation concentration period(PCP) is June 26th.(5)There are lower probability of heavy rain over Zishui basin in 10 days during flood season.The mean probability of heavy rain in 20、30 days are 23.1%、32.2% respectively. On average, the heavy rain center Anhua county has upper probability, the probability of heavy rain in 20、30 days are 39.1%、46.0% respectively. |
| Key words: Hunan Province; Zishui river basin; heavy rain |
