黄土高原北部水蚀风蚀交错带坡面降雨分析

    Rainfall analysis on slope land of wind-water erosion crisscross region in northern Loess Plateau

    • 摘要: 为探明黄土高原北部水蚀风蚀交错带的降雨特点,进而为该地区开展土壤侵蚀、开发利用降雨及地表径流的研究提供科学依据,该文对黄土高原六道沟流域5 a (2006-2010年)雨季的坡面降雨进行了分析。采用Box Car Pro 4.3软件对降雨数据在时间轴上进行分割,分割时间间隔分别为3、5、10 min和1 h,分析了六道沟流域雨季的坡面雨强、降雨历时及降雨量的分布。结果表明,3、5、10 min和1 h时间间隔的最大雨强分别为2.2、2.08、1.68和0.7 mm/min,各时间间隔 5 a内雨季所有降雨历时的平均雨强分别为0.12、0.09、0.06和0.03 mm/min。随着单位时间间隔的增加平均降雨强度降低,各时间间隔的小雨强发生概率远高于大雨强发生概率。3 min时间间隔雨强大于1 mm/min、5 min时间间隔雨强大于1 mm/min、10 min时间间隔雨强大于0.8 mm/min以及1 h时间间隔雨强大于0.4 mm/min发生的概率分别为0.4%、0.2%、0.2%和0.1%。降雨历时小于30 min的降雨事件占总降雨事件的近50%;降雨历时在2 h以上的降雨事件约占总降雨事件的23%,其中降雨历时大于12 h的降雨事件只占总降雨事件的2.6%。降雨量小于等于1 mm 的降雨事件占年均雨季降雨事件的近50%,但其总降雨量不足年均降雨量的7%;降雨量大于20 mm的降雨事件年均5次,其降雨量占年均雨量超过20%。研究结果在一定程度上揭示了黄土高原北部水蚀风蚀交错带的坡面降雨特征。

       

      Abstract: In order to clarify rainfall characteristics, and to provide scientific basis for researches on soil erosion, development and utility on rainfall and surface runoff of the wind-water erosion crisscross region in the northern Loess Plateau, rainfall analysis were performed on the slope land of the Liudaogou Basin in the rainy season in the five years (2006-2010). The observed rainfall data was separated on the time axis by different time intervals of 3 min, 5 min, 10?min and 1 h using Box Car Pro 4.3 software. Rain intensity, distribution of rain duration and rainfall were analyzed. The results showed that the maximum rain intensity of 3 min, 5 min, 10 min and 1 h were 2.2, 2.08, 1.68 and 0.70 mm/min, respectively; average rain intensity of the total rain duration in the rainy season of the five years (2006-2010) were 0.12, 0.09, 0.06 and 0.03 mm/min, respectively; with increasing of the time interval the rain intensity decreased; the event probability of the low rain intensity was much higher than that of the high rain intensity for all series of time intervals; the event probability for 3 min rain intensity > 1 mm/min, 5 min rain intensity >1 mm/min, 10 min rain intensity >0.8 mm/min and 1 h rain intensity > 0.4 mm/min were 0.4%, 0.2%, 0.2% and 0.1%, respectively. The number of rainfall events whose rain duration was less than 30 min accounted for approximately 50% of the total rainfall events, and the number of rain duration > 2 h accounted for approximately 23% of the total; the number of rain duration > 12 h only accounted for 2.6% of the total rainfall events. The number of rainfall events whose rainfall was no more than 1 mm accounted for approximately 50% of the annual mean whereas their total rainfall only accounted for less than 7% of average annual precipitation; annual mean of the rainfall events whose rainfall was more than 20 mm was 5, and the total rainfall of such rainfall events exceeded 20% of average annual precipitation. The rainfall characteristics on the slope land of the wind-water erosion crisscross region in the northern Loess Plateau were clarified to a certain degree.

       

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