陕西省降雨和风蚀气候侵蚀力时空分布特征

Spatio-temporal Characteristics of Rainfall Erosivity and Wind Erosion Climatic Erosivity in Shaanxi Province

[目的]研究陕西省不同区域降雨侵蚀力和风蚀气候侵蚀力的时空分布特征、突变特征和周期特性等,为陕西水土流失防治和生态建设提供科学依据。[方法]利用陕西省96个气象站1981-2020年气象观测资料计算了全省降雨侵蚀力和风蚀气候侵蚀力,采用气候趋势分析、空间插值、M-K检验、小波分析等方法,分析了陕西省风蚀、水蚀气候侵蚀力时空分布特征、突变和周期特征等。[结果](1)全省1981-2020年降雨侵蚀力为2 719.6 MJ·mm/(hm^(2)·h),空间差异性较大,呈现南高北低的空间分布。陕西省风蚀气候侵蚀力为3.18,呈现北高南低的空间分布特征。(2)近40年陕西省降雨侵蚀力年际波动较大,呈现微弱上升趋势,但未通过显著性检验。全省降雨侵蚀力经历了先减小后增大的变化趋势,目前处于降雨侵蚀较大的年代。陕西省风蚀气候侵蚀力年际波动较大,但无显著变化趋势。风蚀气候侵蚀力近40年先增强后减弱,大部分地区风蚀气候侵蚀力在20世纪90年代最强,目前处于最弱的年代。(3)降雨侵蚀力主要以6-9月较大,最大值出现在7月,风蚀气候侵蚀力则以冬春两季较大,4月最大,二者具有明显的非同步性。(4)陕西省降雨侵蚀力存在2~4 a, 8 a和31~32 a共3个时间尺度的振荡周期,风蚀气候侵蚀力变化主要存在5~10 a和31~32 a两个时间尺度的振荡周期。2009年为降雨侵蚀力突变年份,降雨侵蚀力自此逐渐上升,突变前后降雨侵蚀力相差416.27 MJ·mm/(hm^(2)·h)。[结论]目前,陕西省大部分地区降雨侵蚀力均处于较强的时期,尤以陕北北部降雨侵蚀力距平最大,且陕北北部全省风蚀气候侵蚀力最强的区域,榆林东部风蚀气候侵蚀力近40年亦呈上升趋势,该地区风蚀水蚀气候侵蚀力的增长更应引起重视。

[Objective]The spatio-temporal distribution,abrupt change and periodic characteristics of rainfall erosivity and wind erosion climate erosivity in different regions of Shaanxi Province were studied,so as to provide scientific basis for soil erosion control and ecological construction in Shaanxi.[Methods]The daily meteorological data of 96 stations in Shaanxi Province from 1981 to 2020 were used to calculate the rainfall erosivity and wind erosion climatic erosivity to analyze the change of water-wind erosion climate erosivity using methods such as climate trend analysis,spatial interpolation,Mann-kendall trend test and wavelet analysis.[Results](1)The rainfall erosivity in Shaanxi from 1981 to 2020 was 2719.6 MJ·mm/(hm^(2)·h),with large spatial differences,showing a spatial distribution of high in the south and low in the north.The wind erosion climatic erosivity from 1981 to 2020 was 3.18,with a decreasing trend from north to south.(2)In the past 40 years,the rainfall erosivity in Shaanxi showed an evident inter-annual variation with general upward but not passing a significant test.The rainfall erosion experienced a variation trend of first increasing and then decreasing,and it was stronger in the current era.The wind erosion climatic erosivity also showed an evident inter-annual variation,but the change trend was not significant.It experienced a variation trend of first decreasing and then increasing.It was strongest in the 1990s and weakest in the current era.The rainfall erosivity was mainly larger from June to September,and the maximum value appeared in July.The wind erosion climatic erosivity was larger in winter and spring,and the maximum value was in April.The two erosivities were obviously asynchronous.(4)There were three oscillation periods of rainfall erosivity in Shaanxi Province,which was 2~4 years,8 years and 31~32 years.There were two oscillation periods of wind erosion climatic erosivity,which were 5~10 years and 31~32 years.The abrupt change of rainfall erosivity occurred significantly in 2009,since then the rainfall erosivity increased gradually.[Conclusion]At present,the rainfall erosivity in most areas of Shaanxi Province is strong,especially in northern Shaanxi with the strongest wind erosion climate erosivity.The wind erosion climate erosivity in eastern Yulin also showed an upward trend in recent 40 years.Therefore,more attention should be paid to the increase of wind erosion and water erosion climate erosivity in these areas.