黔中喀斯特山地侵蚀性降雨特征及其侵蚀响应

Analysis of erosion rainfall characteristics and erosion response in karst mountain of central Guizhou

分析黔中喀斯特山地黄壤区侵蚀性降雨特征及其径流、泥沙的响应过程,揭示不同雨型下坡面土壤侵蚀特征和坡面土壤侵蚀的季节分布规律。通过数理统计,运用偏相关与K均值聚类对径流小区长序列的产流数据进行特征对比分析及变化规律研究。结果表明:(1)黔中地区降雨频繁、雨量大、历时长,且主要发生在夏半年。(2)降雨量、降雨历时和I_(30min)是降雨因子中影响径流量和侵蚀量的关键要素。(3)黔中地区以雨量小、历时短、强度小、频率高的B雨型为主导,共占总次数的48.21%;但由于D雨型径流量小、侵蚀量大的特性对土壤侵蚀产生的影响更大。(4)各月份土壤侵蚀对不同雨型的响应差异巨大,变化规律均呈先上升后下降的趋势,径流量和侵蚀量最大值都在6—8月。土壤侵蚀隐患较大的月份更需要注重区域的水土保持工作。

This paper analyzes the characteristics of erosive rainfall and the response process of runoff and sediment in the yellow soil region of karst mountainous area in Central Guizhou Province,and reveals the characteristics of soil erosion and the seasonal distribution of soil erosion on the slope under different rainfall patterns.Based on mathematical statistics,partial correlation and K-means clustering are used to analyze the characteristics of long series runoff data of runoff plot,so as to understand the change rules.The results show:(1)In central Guizhou,rainfall is frequent,heavy,and long lasting,and mainly occurs in the summer half of the year.(2)Rainfall,rainfall duration and I30min are the key factors which affect runoff and erosion.(3)The central Guizhou regions are dominated by the B rain pattern with small rainfall,short duration,low intensity,and high frequency,accounting for 48.21%of the total frequency;but the D rain pattern have a greater impact on soil erosion because it is characterized by low frequency and high rainfall.(4)The soil erosion response of different rain patterns varies greatly in each month,and the change pattern shows a trend of first rising and then falling.The maximum runoff and erosion are both in June to August.More attentions should be paid to regional water and soil conservation in months with greater potential soil erosion risk.