青藏高原降雨侵蚀力R因子分布特征及驱动因素

Spatiotemporal distribution and driving factors of rainfall erosivity R factor of Qinghai-Tibet Plateau

降雨侵蚀力R因子是测算土壤侵蚀的重要因子,该因子的准确计算对水土流失动态监测具有重要意义。以青藏高原为研究对象,利用遥感数据和地理信息系统技术,并采用地理探测器模型分析了1991~2020年青藏高原地区降雨侵蚀力R因子的分布特征以及影响因素。研究结果表明:①青藏高原地区R值的变化在分布上大致呈现西北高东南低的特点,C v变差系数在0~0.78之间,年际变化较大的区域分布在青藏高原西北部的和田、阿里地区以及巴音郭楞蒙古自治州的部分地区;而仲巴县、改则县等区县所围成的区域年际变化较小。青藏高原地区降雨侵蚀力R因子的值在0~15532 MJ·mm/(hm^(2)·h·a)之间,均值为648.84 MJ·mm/(hm^(2)·h·a),R值自东向西递减,呈现明显的条带状分布特征,其中在位于青藏高原的南部地区形成了一个明显的高值中心。②影响力探测结果表明,最低气温的解释力最高,q值为0.453,主导降雨侵蚀力R因子的时空分布特征。③交互探测结果表明,青藏高原各因子间协同效应均表现为双因子增强或非线性增强关系,较单因子作用有明显提升。气候因子间的交互作用对降雨侵蚀力R因子的影响较为突出。

The rainfall erosivity R is an important factor for calculating soil erosion,and its accurate calculation is of great significance for the dynamic monitoring of soil erosion.This paper uses remote sensing data and geographic information system(GIS)technology,along with the geographic detector model,to analyze the distribution characteristics and influencing factors of the rainfall erosivity R in the Qinghai-Tibet Plateau from 1991 to 2020.The research results show that:①The interannual variation of the R value in the Qinghai-Tibet Plateau generally exhibited a high in the northwest and a low in the southeast distribution pattern,with a coefficient of variation ranging from 0 to 0.78.Regions with large interannual variations were mainly distributed in the northwest part of the Qinghai-Tibet Plateau,including Hotan,Ngari,and some areas of Bayingolin Mongol Autonomous Prefecture,while regions such as Zhamba County and Gar County had smaller interannual variations.The values of the rainfall erosivity R in the Qinghai-Tibet Plateau ranged from 0 to 15532 MJ·mm/(hm^(2)·h·a),with a mean value of 648.84 MJ·mm/(hm^(2)·h·a).The R value decreased from east to west,showing a distinctly banded distribution pattern.A significant high-value center was found in the southern part of the Qinghai-Tibet Plateau.②The influence detection results indicated that the minimum temperature has the highest explanatory power,with a q value of 0.453,dominating the spatiotemporal distribution characteristics of the rainfall erosivity R.③The interaction detection results showed that the synergistic effects among various factors on the Qinghai-Tibet Plateau exhibited either a two-factor enhancement or a nonlinear enhancement relationship,significantly surpassing the single-factor effects.The interaction effect among climate factors had a prominent impact on the rainfall erosivity R.