作　　者： ;

机构地区： 佛山科学技术学院

出　　处： 《热带地理》 2020年第1期145-153,共9页

摘　　要： 选取北江流域18雨量站1961-2017年逐日降水数据,采用降水发生率、降水贡献率指标,利用Mann-Kendall法进行变化趋势检验,分析流域汛期(3-8月)不同历时、不同等级降水结构的时空变化特征,结果表明:1)汛期降水发生率随降水历时的增加大致呈指数形式递减,其中1~4d历时降水发生率合计69.88%;降水贡献率随降水历时的增加而先增加后减小、到≥10 d历时又显著增加。降水贡献率的空间差异主要表现为历时2~4 d与历时≥10 d在北部与东南部反向变化。2)降水发生率随降水等级的增加而减小,其中小雨发生率约占65%;西部大雨贡献率偏高;东南部暴雨贡献率偏高,其中清远、佛冈站约为39%。3)中短历时(1~6d)降水发生率呈不显著下降趋势,而贡献率呈不显著上升趋势;长历时(≥7 d)降水发生率、贡献率均呈显著下降趋势。各等级降水变化趋势方面,小雨、中雨发生率、贡献率不显著下降,大雨、暴雨发生率、贡献率不显著上升。 Although precipitation in the Beijiang River Basin has been discussed in many previously conducted studies, precipitation structure has been rarely investigated. Therefore, this study analyzes the spatial–temporal variation characteristics of precipitation structure in the rainy season(from March to August) using 50 years of daily precipitation data for the Beijiang River Basin. The precipitation duration and precipitation grade are specifically addressed using the precipitation incidence rate and precipitation contribution rate indexes.The results show that 1) the precipitation incidence rate decreases exponentially with an increase in the precipitation duration and increases with an increase in the precipitation grade. As the precipitation duration increases, the precipitation contribution rate initially increases and then decreases. 2) The spatial difference of incidence rate for different durations appears as a local high or low spatial difference(island distribution) for durations of 1-2 days and≥10 days. The spatial difference of contribution rate for different durations can be observed as a reverse change in the north and southeast directions that appear at durations of 2-4 days and≥10 days. 3) Regionally, the incidence rate of the events graded as light rain and torrential rain were mainly reflected in the reverse changes in the north(including Lechang, Shixing, and Nanxiong) and the southeast(including Fogang, Qingyuan, and Yingde). The contribution rate of heavy rain was high in the west, and the contribution rate of torrential rain in Qingyuan and Fogang in the southeast was about 39%, making the torrential rain center in Beijiang river basin. 4) Short and medium duration events(1-6 days) did not significantly decrease, and the contribution rate did not significantly increase. However, the incidence and contribution rates for long duration events(≥7 days) decreased. No change was observed across all the precipitation grades;the incidence and contribution rate of light rain and moderate rain did

关 键 词： 降水结构 汛期 降水历时 降水等级 北江流域

分 类 号： [TV125;TV121]

领　　域： []