气候变化影响中国东北地区降水侵蚀力的高分辨率区域模式预估

Projection of Rainfall Erosivity under Climate Change in Northeast China Using a High-Resolution Regional Model

土壤侵蚀是生态环境和农业生产的重要影响因子。我国东三省土地面积79.33万平方公里,占我国国土面积的9.3%,是重要的商品粮基地,同时也是世界四大黑土区之一。在气候变化背景下,我国东北地区的土壤侵蚀情况及其未来风险,目前仍不清楚。影响土壤侵蚀力的重要因素之一是降水侵蚀力(R-factor),其与强降水有关。本研究利用CN05.1和APHRODITE观测降水资料揭示了我国东北地区降水侵蚀力的观测特征。在气候平均态上,东北地区东南部降水侵蚀力最强。降水侵蚀力存在明显的年循环,以夏季为主导,占全年总侵蚀的80%以上。在观测分析基础上,对RegCM4动力降尺度模式进行了评估和订正,并预估了未来不同共享社会经济路径(SSP1-2.6和SSP5-8.5)下中国东北地区降水侵蚀力的变化。随着未来增温,到21世纪末,两种排放情景下东北地区平均的降水侵蚀力分别增加9.90%和26.70%。高排放情景下将面临更严重的降水侵蚀风险,SSP5-8.5情景下降水侵蚀力的增强幅度约为SSP1-2.6情景下变化的2.7倍,同时77.69%的区域面积上降水侵蚀力将更强。因此,采取切实有效的减排措施,走可持续发展路径,对于减缓我国东北地区黑土地的土壤侵蚀风险,进而保障粮食安全,具有重要意义。

Soil erosion is an important factor affecting the ecological environment and agricultural production globally.The three northeastern provinces of China have an area of 793300 km2,accounting for 9.3%of its total land area.These provinces are among the four black soil regions in the world and an important commodity grain base.Soil erosion in Northeast China and its future risks are still unclear given climate change.The main meteorological factor affecting soil erosivity is heavy precipitation.Based on this relationship,the observational precipitation data of CN05.1 and APHRODITE were used to reveal the characteristics of rainfall erosivity in Northeast China.In terms of the mean climate,rainfall erosivity is the strongest in the southeast of Northeast China.The rainfall erosivity shows an evident annual cycle.Rainfall erosivity in summer(June–July–August)contributes to over 80%of the annual total.Based on the observational analysis,the RegCM4 dynamic downscaling model is evaluated and bias-corrected.The future changes in the rainfall erosivity in Northeast China under different shared socioeconomic pathways(SSP1-2.6 and SSP5-8.5)are subsequently examined.With future global warming,the mean rainfall erosivity in Northeast China will increase by 9.90%and 26.70%,respectively,by the end of the 21st century.Under the high-emission scenario(SSP5-8.5),a higher risk of rainfall erosion is expected,with a rainfall erosivity 2.7 times greater than that under the SSP1-2.6 scenario,and 77.69%area is projected to experience more severe rainfall erosivity.Therefore,it is of great significance to deploy effective emission reduction measures and follow sustainable development to reduce the soil erosion risk of black land in Northeast China and ensure food security.