赣江上游平江流域近30年不同量级降雨日数时空分布特征

Spatial and temporal distribution characteristics of rainfall days of different magnitudes in Pingjiang basin of upper Ganjiang River in recent 30 years

以赣江上游平江流域为研究对象,基于9个雨量站点1989-2018年逐小时降水数据,运用Mann-Kendall趋势检验法和反距离权重插值法对不同量级降雨日数在年、季、月尺度上进行分析。结果表明:(1)近30年来,平江流域小、中、大、暴雨日占总降雨日数的比率分别为67.71%、19.90%、9.17%、3.22%,降雨日数以小雨日为主,小、中、大、暴雨日分别集中在春、春、春、夏季,小、中、大、暴雨日月特征分别集中在1~6、2~8、3~8、5~8月;(2)各量级降雨日数在各尺度上的空间分布为小雨日主要集中在流域南部,暴雨日主要为南低北高,中、大雨日差异较大;(3)趋势分析得到,小、中雨日在月尺度上表现相对活跃,11月小、中雨日呈显著上升趋势,大、暴雨日则无明显变化。结论:对于流域灾害防治,应更加关注5、6月流域北部由暴雨引发的自然灾害;对于水资源开发利用主要关注9~12月。研究对于流域山洪防治、水土流失治理及天气变化等方面的研究具有重要的参考价值。

Based on the hourly precipitation data of 9 rainfall sites from 1989 to 2018,the Mann-Kendall trend test method and the anti-distance weight interpolation method were used to analyze the number of days of rainfall in different magnitudes on the annual,seasonal and monthly scales.The results showed that:(1)in the past 30 years,the proportion of light rain,moderate rain,heavy rain and excessive rain days in Pingjiang basin was 67.71%,19.90%,9.17%and 3.22%respectively.Rainfall days were mainly light rain,and moderate rain,heavy rain,excessive rain days with seasonal distribution were concentrated in spring,spring,spring,summer,and light rain,moderate rain,heavy rain,excessive rain days of the month characteristics were concentrated form January to June,February to August,March to August,May to August.(2)The spatial distribution of rainfall days in each magnitude:the number of light rain days mainly concentrated in the southern part of the basin,the number of excessive rain days mainly large in the was south and north,The number of moderate rain and heavy rain days with spatial distribution characteristics varied greatly.(3)According to the analysis of Mann-Kendall trend,the number of light rain and moderate rain days showed relatively active on the monthly scale,while the number of light rain and moderate rain days in November showed a significant upward trend,while the number of heavy rain and excessive rain days did not significantly changed.It can be concluded from the results that:for the prevention and control of river basin disasters,more attention should be paid to natural disasters caused by heavy rains in the northern part of the basin in May and June;for water resources development and utilization,the main focus should be paied on the period from September to December.The research is of great reference value to the research on flood prevention and control,soil erosion control and weather change in the basin.