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    杨云斌, 张建军, 李梁, 孙若修, 张海博, 张佳楠. 晋西黄土区降雨过程对小流域产流的影响[J]. 北京林业大学学报, 2019, 41(3): 105-114. DOI: 10.13332/j.1000-1522.20180104
    引用本文: 杨云斌, 张建军, 李梁, 孙若修, 张海博, 张佳楠. 晋西黄土区降雨过程对小流域产流的影响[J]. 北京林业大学学报, 2019, 41(3): 105-114. DOI: 10.13332/j.1000-1522.20180104
    Yang Yunbin, Zhang Jianjun, Li Liang, Sun Ruoxiu, Zhang Haibo, Zhang Jianan. Effects of rainfall process on runoff in small watersheds in the Loess Plateau of western Shanxi Province, northern China[J]. Journal of Beijing Forestry University, 2019, 41(3): 105-114. DOI: 10.13332/j.1000-1522.20180104
    Citation: Yang Yunbin, Zhang Jianjun, Li Liang, Sun Ruoxiu, Zhang Haibo, Zhang Jianan. Effects of rainfall process on runoff in small watersheds in the Loess Plateau of western Shanxi Province, northern China[J]. Journal of Beijing Forestry University, 2019, 41(3): 105-114. DOI: 10.13332/j.1000-1522.20180104

    晋西黄土区降雨过程对小流域产流的影响

    Effects of rainfall process on runoff in small watersheds in the Loess Plateau of western Shanxi Province, northern China

    • 摘要:
      目的探究降雨过程(雨型)对小流域产流过程的影响,为小流域尺度上产汇流分析提供依据。
      方法以山西吉县森林生态系统国家野外科学观测研究站的蔡家川小流域为研究对象,利用蔡家川小流域2007—2017年场降雨径流数据,根据雨量在降雨过程中集中的位置进行雨型划分,并采用LSD多重比较法分析不同雨型的特征,在不同土地利用类型的小流域尺度上探究雨型特征与产流的响应关系。
      结果(1)蔡家川流域的降雨可划分为前期型降雨(I型)、中期型降雨(Ⅱ型)、后期型降雨(Ⅲ型)和均匀型降雨(Ⅳ型)。Ⅰ型降雨为短历时强降雨,是主要降雨雨型,占总降雨频次的44.6%,平均雨量为24.6 mm,降雨侵蚀力最强,集中分布在6—8月;Ⅳ型降雨为长历时小雨强降雨,平均历时716 min,平均雨量为17.84 mm,降雨侵蚀力最弱,多出现在雨季的前期(5月份)和后期(9月份);Ⅱ型和Ⅲ型降雨的特征介于Ⅰ型和Ⅳ型降雨之间,多发生在6—8月,降雨量和频次相对均衡。(2)不同雨型条件下小流域的径流深、洪峰流量排序为:Ⅰ型降雨 > Ⅲ型降雨 > Ⅱ型降雨 > Ⅳ型降雨,洪峰滞后时间排序为:Ⅳ型降雨 > Ⅱ型降雨 > Ⅲ型降雨 > Ⅰ型降雨。(3)Ⅰ型、Ⅲ型降雨条件下农地小流域的径流深和洪峰流量高于封禁小流域,Ⅱ型和Ⅳ型降雨条件下封禁小流域的径流深和洪峰流量略高于农地小流域,封禁小流域的洪峰出现时间均滞后于农地小流域。(4)降雨量和历时对农地小流域产流的影响更大,雨强分布对封禁小流域产流的影响更大。
      结论不同雨型的降雨特征差异性显著,Ⅰ型降雨是引起小流域产流的主要雨型,大雨量强降雨更易造成流域的水土流失;封禁小流域削减径流、延长洪峰出现时间的作用显著,尤其对大雨量强降雨的调节作用更明显;在晋西黄土区降雨量、降雨历时和降雨过程中的雨强分布是影响小流域产流过程的重要因素。

       

      Abstract:
      ObjectiveThis study aims to discuss the effects of precipitation process (rainfall patterns) on runoff in small watersheds, and provide the basis for the analysis of runoff and confluence on a small watershed scale.
      MethodCaijiachuan Small Watershed of the National Field Research Station of Forest Ecosystem in Jixian County, Shanxi Province of northern China was taken as the research object. Rainfall and runoff data were collected from 2007 to 2017 in the Caijiachuan Watershed and rainfall patterns were divided according to the location of rainfall in the precipitation process. LSD multiple comparison method was used to study rainfall characteristics of different rainfall patterns on the basis of rainfall process. The response relationship between rainfall pattern characteristics and runoff was explored in small watershed scales of different land use types.
      Result(1)The storms were divided into four rainfall patterns: rainfall concentrated early in the rainfall (Type Ⅰ); rainfall concentrated in the middle of the rainfall (Type Ⅱ); rainfall concentrated at the end of the rainfall (Type Ⅲ); and rainfall distributed uniformly over time (Type Ⅳ). Type I was characterized by shorter durations and higher intensities, which was the main type of rainfall, accounting for 44.6% of the total rainfall frequency. The average rainfall was 24.6 mm and rainfall erosivity was the strongest, which concentrated in June to August. Type Ⅳ had longer durations and lower intensities, with an average duration of 716 minutes and an average rainfall of 17.84 mm, rainfall erosivity was the weakest, mostly occurring in the early (May) and late (September) phases of the rainy season. The characteristics of Type Ⅱ and Type Ⅲ were between TypeⅠ and Type Ⅳ, which mostly occurred from June to August. The distribution of rainfall and frequency was relatively balanced. (2) The order of runoff depth and peak discharge in small watersheds under different rainfall patterns was Type Ⅰ > Type Ⅲ > Type Ⅱ > Type Ⅳ, lag time of flood peak was Type IV > Type II > Type III > Type I. (3) Runoff depth and peak discharge in the agricultural small watershed under Type I and Type III were higher than that in the closed small watershed, which was the opposite under Type II and Type IV. The peak flow appeared earlier in the agricultural small watershed. (4) Rainfall and duration had a greater impact on the runoff in the agricultural small watershed, intensity distribution had greater impact on the runoff in the closed small watershed.
      ConclusionThe rainfall characteristics of different rain patterns are significantly different. Type Ⅰ was the main rainfall pattern causing the runoff of small watersheds. The closed small watershed had a more significant role in reducing peak discharge and prolonging the appearance time of peak flow than the agricultural small watershed, especially for heavy rainfall and strong rainfall, the regulation effect was more obvious. The rainfall, rainfall duration and rainfall intensity distribution in the Loess Plateau of Western Shanxi Province are the important factors influencing the runoff production in small watershed.

       

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