| Soil erosion has become one of the most important ecological and environmental problems in the world,and it has received increasing attention and research from all over the world.Rainfall erosivity refers to the potential for soil erosion caused by rainfall.And it is one of the most important factors affecting soil erosion.Studying the temporal and spatial distribution characteristics of rainfall erosivity has positive significance for soil loss prediction and soil and water conservation planning.Based on the meteorological data of 5 meteorological stations in Tang-Qin area from 1960 to 2015 and the rainfall process data of Taolinkou Reservoir from 2005 to 2017,this paper establishes the erosive rainfall standard in Tang-Qin areas,Quantitative study and comparative analysis were used.analyzes rainfall and erosive rainfall,and establishes suitable The rainfall erosivity model of the daily,monthly and annual rainfall in the Tang-Qin finally reveals the temporal variation and spatial distribution of rainfall erosivity in the Tang-Qin regions,can provide a reliable basis for the development of soil and water conservation planning and soil erosion control programs in the region.The research results are as follows:(1)The average annual rainfall in Tang-Qin areas is 639 mm,the rainfall is decreasing,and the annual average is 2.26 mm.The annual rainfall is the first main cycle with the 28-year time scale,and the 14-year time scale is the second main cycle.In the Tang-Qin regions,June-September was the most erosive time of the year,especially in July.In the Zunhua City of Space Mountain,the rainfall in Qinglong County and Qinhuangdao City is high.(2)The erosive rainfall standard in Tang-Qin area is 16 mm,the erosive rainfall intensity standard is 16.2 mm/h,the average annual erosive rainfall in Tang-Qin area is 448 mm,and the erosive rainfall is decreasing,with an average annual reduction of1.79 mm,the annual erosive rainfall is the first main cycle with the 14-year time scale,and the 6-year time scale is the second main cycle.June-September is the most erosive rainfall in the year,especially in July.In space,the average annual erosive rainfall in the Tang-Qin regions decreased from the highest to the southeast in the northwest of Tangshan,and decreased to the southwest in the northeast of Qinhuangdao.The high-value centers appeared in Zunhua,Qinglong and Qinhuangdao.(3)Using the EI model in Taolingkou Reservoir and the four types of daily rainfall rainfall erosivity models commonly used in China to calculate rainfall erosivity for comparison and regression analysis,it is found that the modified Zhang Wenbo's daily rainfall model is more suitable for calculating rainfall erosivity in Tang-Qin area.According to this model,the rainfall erosivity of the Tang-Qin area was calculated from 1960 to 2015.The calculation formula of rainfall erosivity based on monthly and annual rainfall was obtained by fitting.(4)The average annual rainfall erosivity in Tang-Qin areas is 4973.33MJ·mm/(hm~2·h),and the rainfall erosivity is decreasing,with an average annual reduction of 23.17 MJ·mm/(hm~2·h).The annual rainfall erosivity is the 14-year time scale is the first main cycle,and the 6-year time scale is the second main cycle,In the Tang-Qin area,June-September was the most erosive time of the year,especially in July.In space,the average annual rainfall erosivity of the Tang-Qin region has gradually increased around the Taolinkou Reservoir.The rainfall erosivity of Zunhua City,Qinglong County and Qinhuangdao City is relatively high,and the prevention and control of soil erosion in this area should be strengthened. |
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