| 摘要: |
| 【目的】在分析侵蚀性降水特征的基础上，构建基于降水特征的次降水侵蚀力估算模型，研究结果可为区域水土流失定量监测和水土保持效益评价提供参考。【方法】利用甘肃黄土丘陵沟壑区安家沟小流域和龙滩小流域2个典型径流场5 a的侵蚀性降水过程资料，构建雨量（P）×雨强（I）结构与E×I30的转换关系。【结果】结果表明：>50 MJ·mm/(hm2·h)的次降水侵蚀力占侵蚀力总量的比例高达75%，是该地区降水侵蚀力的主要贡献来源。降水量P和降水动能E之间呈线性函数关系，E=0.2057P-1.0671（R2=0.763，n=48）。降水单因子I30（30分钟降水强度）、I60（60分钟降水强度）、E（降水动能）对土壤流失量（S）产生显著影响（P<0.01）。降水双因子P×I30、P×I60与S之间的相关系数r > 0.616（P<0.01），P×I30、P×I60是影响坡面土壤流失量S的主要降水复合因子。P×I30、P×I60与E×I30符合幂函数关系，模型方程决定系数R2达到0.984 0、0.9609。2个模型的有效系数分别为98.9%、98.1%，偏差系数分别为2.0%、3.2%。当10 mm < P < 50 mm时，2个模型的预测值相对误差均不超过16%，对于>50 MJ·mm/(hm2·h)的次降水侵蚀力预测值相对误差<10%。【结论】模型预测效果良好，指标因子P×I30、P×I60可作为该区域10 mm < P < 50 mm次降水侵蚀力指标因子。 |
| 关键词: 黄土丘陵沟壑区；安家沟流域；水土流失；降雨侵蚀力；侵蚀性降雨 |
| DOI： |
| 分类号:S157.1 |
| 基金项目: |
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| Estimation Model of Individual Rainfall Erosivity Based on Rainfall Characteristics ―Taking typical small watershed in the loess hilly and gully region in Gansu Province as a Case |
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zhuyanqin
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Gansu Agricultural University
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| Abstract: |
| 【Objective】Based on the analysis of individual erosive rainfall characteristics, to build the model of rainfall erosivity, the research results can provide reference for quantitative monitoring of regional water and soil loss and benefit evaluation of water and soil conservation.【Method】Erosive rainfall process data for five years were obtained from two typical runoff fields of Anjiagou small watershed and Longtan small watershed in the loess hilly and gully region in Gansu Province, the conversion relationship between the structure of rainfall (P) × rain intensity (I) and E×I30 were established.【Result】The results showed: rainfall erosivity above 50 MJ·mm/(hm2·h) were the main sources of rainfall erosivity in this area, accounting for 75% of the total erosivity. There was a linear function relationship between rainfall P and rainfall kinetic energy E, E=0.2057P-1.0671 (R2=0.763，n=48) . Rainfall single factors I30 (30-minute rainfall intensity), I60 (60-minute rainfall intensity) and E (rainfall kinetic energy) had a significant impact on soil loss (S) (P<0.01). The correlation coefficients (r) between P×I30, P×I60 and S were >0.616 (P<0.01), hence P×I30 and P×I60 were the main rainfall compound factors affecting the soil loss (S) on the slope. The relationship between P×I30, P×I60 and E×I30 conformed to the power equation, with the determination coefficient R2of 0.984 0, 0.9609. The effective coefficients of the two models were 98.9% and 98.1%, while the deviation coefficients were 2.0% and 3.2%, respectively. The rainfall was 50 mm>P>10 mm, the relative error of the predicted values of the two models was not more than 16%. The rainfall erosivity was above 50 MJ·mm/(hm2·h), the relative error of rainfall erosivity prediction values was less than 10%. 【Conclusion】The two models have good prediction effect. Therefore, rainfall is 50 mm>P>10 mm, P×I30, P×I60 can be used as index factors of individual rainfall erosivity in the region. |
| Key words: Loess hilly and gully region; Anjiagou small watershed; Water and soil loss; Rainfall erosivity; Erosive rainfall |
