1951-2018年华南前汛期暴雨特征分析——以韶关市为例

Analysis on Characteristics of Rainstorm in South China During the Previous Flood Season from 1951 to 2018——Taking Shaoguan City as an Example

研究长时间尺度的华南前汛期暴雨特征,为该区暴雨的预测预防提供参考。利用韶关市1951—2018年逐日降水资料,采用M-K检验法、morlet小波分析法和皮尔逊三型频率曲线,研究了韶关市前汛期(4—6月)不同等级暴雨变化的趋势、突变点和周期变化规律及重现期。结果表明:(1)韶关市68年间前汛期暴雨对前汛期降水贡献大,平均贡献率为27%,前汛期降水量呈明显的增加趋势;(2)暴雨等级的雨量突变年份在1953年、1957年、2006年、2015年,而大暴雨等级雨量的UF曲线大于U0.01临界值,大暴雨等级的雨量在1951年,1952年的上升及在1960年、1961年、1963—2018年的下降趋势均十分显著;(3) 68 a来韶关市的前汛期不同等级暴雨日数呈现多重震荡周期性规律,暴雨日数的主要震荡周期是6 a, 8 a, 15 a, 22 a,大暴雨日数的主要震荡周期是4 a, 8 a, 15 a, 27 a;(4)暴雨频次较多的属于小概率事件、频次较少的发生概率较大。研究为韶关市抗洪防灾、水土保持等工作提供参考。

To study the characteristics of rainstorm in pre-flood period in South China on a long time scale, and to provide reference for the prediction and prevention of rainstorm in this area, based on the daily precipitation data of Shaoguan City from 1951 to 2018, we used M-K test method, Morlet wavelet analysis method and Pearson three-type frequency curve to study the variation trend, abrupt change point, periodic change rule and recurrence period of rainstorm of different grades in the pre-flood period(April to June) of Shaoguan City. The results show that: in 68 years, the average contribution rate of rainstorm in the pre-flood period was 27%, and the precipitation in the pre-flood period showed an obvious increasing trend;the abrupt transition years of the rainstorm grade were found in 1953, 1957, 2006 and 2015, and the UF curve of the rainstorm grade was greater than the U0.01 critical value, so the rainstorm grade increased in 1951 and 1952 and decreased significantly in 1960, 1961 and 1963 to 2018;the number of rainstorm days of different grades in the pre-flood season to Shaoguan City presented multiple cyclical patterns;the main fluctuation cycles of rainstorm days are 6 years, 8 years, 15 years and 22 years, while the main fluctuation cycles of rainstorm days are 4 years, 8 years, 15 years and 27 years;the occurrence probability of rainstorms with more frequency and less frequency was large. The study on the variation trend, abrupt change point, periodic change rule and recurrence period of rainstorm of different grades in the pre-flood period of Shaoguan City can provides the references for flood prevention, soil and water conservation and other work in Shaoguan City.