| Soil erosion has caused extensive land degradation worldwide and is one of the most serious environmental problems.Water erosion is the main type of soil erosion.Studying the temporal and spatial distribution of rainfall and rainfall erosivity is of great significance to soil erosion forecasting,soil and water conservation monitoring,and water and soil conservation planning.Based on the daily rainfall data of 9 stations in the Taihang Mountains of Hebei Province for the past 19 years,12 stations in the Yanshan Mountains for 59 years,and 12 stations in the surrounding areas of Hebei Province for 56 years,the paper uses trend analysis,cycle analysis,mutation analysis,Tyson polygon and Kerry The golden interpolation method researched and analyzed the temporal and spatial variation characteristics of rainfall,rainfall frequency and rainfall erosivity in Taihang Mountain and Yanshan Mountain of Hebei Province.The research results are helpful to grasp and understand rainfall and rainfall erosivity in Hebei Province.And can provide a reference for the formulation of soil and water conservation plans in Hebei Province.The research results are as follows:(1)The multi-year average rainfall in the Taihang Mountains is 497.91 mm,with an average increase of 5.876 mm every 10 years.6 years is the first main cycle,which changes abruptly in 2004 and 2014;the four seasons have a relatively average change cycle,with a sudden change in spring in 2012.The highest rainfall in summer is 315.39 mm,reaching 63%of the annual rainfall.The annual average rainfall in the Yanshan Mountains is 507.14 mm,with an average decrease of 3.922 mm every 10 years.The 22-year period is the main cycle,and abrupt changes occurred in 1979 and 1985.In the four seasons,the highest rainfall in summer is 350.4 mm,reaching 69%of the annual total.The maximum period is 26 years,and mutations have occurred in all four seasons.The spatial distribution of rainfall in the Taihang Mountains gradually decreases from south to north,and the spatial distribution varies greatly due to factors such as topography and rainfall inequality,showing the characteristics of multi-center distribution;the Yanshan Mountains gradually increase from west to east.(2)The multi-year average rainfall frequency in the Taihang Mountains is 72 days,with an average increase of 1.18 days every 10 years,with a change period of 6 years and no mutation points;the highest rainfall frequency in summer is 33 days,accounting for 46%of the year.The change cycle of the four seasons is relatively even,and there is no mutation point.The multi-year average rainfall frequency in Yanshan Mountain is 73 days,with an average increase of 1.229 days every 10 years,with an 8-year main cycle,and abrupt changes in 1965 and 1972;the highest rainfall frequency in summer is 37 days,accounting for 51%of the year,and the main cycle of winter variation is the largest 26 Sudden changes occurred in the four seasons of the year.The spatial distribution of rainfall frequency is higher in the west and northwest of the Taihang Mountains,and higher in the northwest of the Yanshan Mountains.(3)The average rainfall erosivity for many years is 2554.36 MJ·mm/(hm2·h)in the Taihang Mountains,an average decrease of 36.96 MJ·mm/(hm2·h)every 10 years.The main period is 6 years,and the maximum period in autumn is In 10 years,a sudden change occurred in the spring;the Yanshan mountain area was 2741.44 MJ·mm/(hm2·h),an average decrease of 89.053 MJ·mm/(hm2·h)every 10 years.The 13th year is the first major cycle,and the summer major cycle is the largest 28 Sudden changes occurred in summer and autumn in the year.As for the spatial distribution of rainfall erosivity,the Taihang mountainous area is high in the southern area,and the Yanshan mountainous area is multi-centered,with high-value centers appearing in Tianzhen County.(4)Rainfall erosivity has a significant correlation with rainfall.The correlation coefficients between Taihang Mountain and Yanshan Mountain are 0.82 and 0.92,respectively,and the correlation is the highest in summer.There is no obvious correlation between rainfall erosivity and rainfall frequency. |
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