河南省降雨侵蚀力的时空变化特征分析

Spatio-temporal variation characteristics of rainfall erosivity in Henan province

为探究河南省长时间序列降雨侵蚀力的时空格局与变化趋势,基于河南省1981—2020年90个气象站点的逐日降雨资料,利用日降雨侵蚀力计算模型,通过莫兰指数、趋势系数和Mann-Kendall检验,分析半月、季节和年降雨侵蚀力的空间分布与趋势变化。结果表明:河南省多年平均降雨侵蚀力在1696~6106 MJ·mm/(hm^(2)·h)之间,呈现出自东南向西北递减的趋势。春季、夏季和冬季降雨侵蚀力也呈现相似的分布特点,而秋季降雨侵蚀力的南北分异则更为明显。全年和季节降雨侵蚀力均呈现显著的集聚性,降雨侵蚀力高—高聚集区主要集中于河南省南部地区,发生降雨侵蚀的风险较高。降雨侵蚀力年内分布不均,年际间波动较大,但变化并不显著。降雨侵蚀力主要集中于夏季,且绝大多数年份的夏季降雨侵蚀力呈增长趋势。桐柏—大别山山地丘陵区、豫西黄土丘陵区、河南省东部黄泛区都面临着较高的降雨侵蚀风险。研究结果可为河南省水土流失动态监测、水土保持规划以及土壤侵蚀防治提供科学依据。

[Background]Rainfall erosivity is the potential capacity of water erosion caused by rainfall.It is an important factor in soil erosion models including USLE(Universal Soil Loss Equation),RUSLE(Revised Universal Soil Loss Equation)and CSLE(Chinese Soil Loss Equation).Soil erosion is relatively serious in Henan province,and the research of rainfall erosivity has been paid much attention.However,relevant studies are far from enough.Analyzing the spatial distribution and trend variation of half month,seasonal and annual rainfall erosivity may provide scientific basis for regional soil erosion assessment and prevention.[Methods]Based on the daily rainfall data of 90 meteorological stations in Henan province from 1981 to 2020,this paper used the daily rainfall erosivity calculation model to detect the spatio-temporal patterns and variation of rainfall erosivity through Moran index,trend coefficient and Mann-Kendall test.[Results]1)The multi-year-average rainfall erosivity of Henan province ranged from 1696 to 6106 MJ·mm/(hm^(2)·h),showing a decreasing trend from southeast to northwest.The rainfall erosivity in spring,summer and winter also presented similar distribution characteristics,while the north-south differentiation of rainfall erosivity in autumn was more obvious.The high-high concentration areas of rainfall erosivity were mainly concentrated in the southern part of Henan province,with a high risk of rainfall erosion.2)The annual and seasonal rainfall erosivity showed a significant concentration.Rainfall erosivity was mainly concentrated in summer,and there existed an increasing trend of summer rainfall erosivity in most years.[Conclusions]Rainfall erosivity in Henan province was unevenly distributed within the year and fluctuated greatly,but the change was not significant.Tongbai-Dabie Mountain area,Loess Hilly Region of western Henan province,and Yellow River Flood area in eastern Henan province all had higher risk of rainfall erosion.The results can provide scientific basis for dynamic monitoring of soil erosion,soil and water conservation planning and soil erosion prevention in Henan province.