| 摘要: |
| 【目的】对陇东地区降雨侵蚀力的时空变化特征进行研究，为认知该区域水土流失规律和指导水土保持工作提供参考。【方法】以陇东地区正宁、宁县、西峰、镇原、合水、庆城、华池和环县等8个区县气象站2001－2011年日降雨量资料为基础，采用日降雨量侵蚀力模型计算各站点降雨侵蚀力值，探讨分析了该区域降雨侵蚀力的年际变化和年内分布特征，并结合GIS软件分析了陇东地区年降雨侵蚀力的空间分布规律。【结果】陇东地区各区县气象站点年均降雨侵蚀力为1 144.8～2 048.5 MJ·mm/(hm2·h)，且东南部明显高于西北部；中南部地势低洼的宁县和合水县由于侵蚀性降雨集中，其降雨侵蚀力值大于东南部年降雨量和侵蚀性降雨量最大、侵蚀性降雨天数最多的正宁县。区域降雨侵蚀力年内高度集中，各区县气象站点6－9月降雨侵蚀力占全年的84.4%～88.8%，呈显著的单峰型分布。区内降雨侵蚀力年际波动较大，各站点年际变率为29.09%～56.55%。趋势分析表明，陇东8个区县的年降雨侵蚀力总体呈减小趋势，其中华池和环县降雨侵蚀力减小显著 (P<0.05)。【结论】陇东地区年内80%以上的降雨侵蚀力集中在6－9月，空间上则由东南向西北递减，从时间上看，近年来该地区降雨侵蚀力呈减小趋势。 |
| 关键词: 降雨侵蚀力 日降雨量侵蚀力模型 时空分布 陇东地区 |
| DOI： |
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| 基金项目:国家自然科学基金项目(41201214) |
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| Spatial and temporal variability of rainfall erosivity in Eastern Gansu |
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WU De-yong,ZHANG Xin,LI Qi-quan,et al
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| Abstract: |
| 【Objective】This study focused on the spatial and temporal variability of rainfall erosivity in Eastern Gansu.【Method】Based on daily rainfall data during 2001－2011 at 8 meteorological sites including Zhengning,Ningxian,Xifeng,Zhenyuan,Heshui,Qingcheng,Huachi and Huanxian in Eastern Gansu,the rainfall erosivity was estimated using the daily rainfall erosivity model and its spatial and temporal variability was analyzed.【Result】The rainfall erosivity per year of Eastern Gansu ranged from 1 144.8 to 2 048.5 MJ·mm/(hm2·h),and it declined from southeast to northwest.Due to the concentrated erosive rainfall,erosivities of Ningxian and Heshui in south central part with low elevation were larger than that of Zhengning in southeast with largest erosive rainfall and number of days with erosive rainfall.The rainfall erosivity was highly centralized with 84.4%－88.8% during June to September.The inter-annual variation of rainfall erosivity was large with coefficient of 29.09%－56.55%.Trend analysis shows that the overall annual rainfall erosivities at the 8 meteorological sites had a declining trend in recent years,with significant decrease in Huachi and Huanxian.【Conclusion】More than 80% of rainfall erosivity in Eastern Gansu happened during June to September.The spatial distribution of annual rainfall erosivity appeared a decreasing trend from southeast to northwest.The annual rainfall erosivity of this area showed a declining trend in recent years. |
| Key words: rainfall erosivity daily rainfall erosivity model spatial-temporal characteristics Eastern Gansu Province |
