基于SSA-BP神经网络模型的全球入海径流量未来变化趋势OA北大核心CSTPCD

Runoff into the sea is an important link in the water cycle.Exploring the spatial and temporal variation characteristics of global runoff into the sea under the background of climate change can provide a basis for the rational utilization of water resources.Based on the monthly discharge of 376 outflow rivers around the world,ERA5-LAND reanalysis data and 10 global climate models,a precipitation-runoff relationship model based on the SSA-BP neural network was constructed to analyze the spatiotemporal change characteristics of the global runoff into the sea during the historical period(1961-2020)and the future(2021-2100)under three scenarios(SSP1-2.6,SSP3-7.0 and SSP5-8.5).The results are as follows.(1)On a global scale,from 1961 to 2020,the multi-year average annual runoff into the sea was 37423 km3.From 2021 to 2100,the global annual runoff into the sea will show an increasing trend under the three future scenarios,with a significant trend under the SSP1-2.6 scenario.Compared with the base period,the late 21st century showed the largest increase.(2)On an intercontinental scale,during historical periods,Africa's runoff into the sea showed a significant decreasing trend,while North America showed a significant increasing trend.From 2021 to 2100,Asia and North America will show an increasing trend under three scenarios,Oceania will show a decreasing trend,and there are obvious differences among the scenarios for the remaining continents.(3)In terms of latitudinal distribution,the change trend in the low latitudes of the Northern and Southern Hemispheres during the historical period was not significant;the mid-latitude Northern Hemisphere showed a weak decreasing trend,the Southern Hemisphere showed a significant decreasing trend;and the high latitudes of the Northern Hemisphere showed a significant increasing trend.From 2021 to 2100,from low to high emission scenarios,the increasing trend of runoff into the sea in the low latitudes of the Northern Hemisphere and the decreasing trend in the Southern Hemisphere become more and more significant;in the mid-to-high latitudes of the Northern Hemisphere,the significant increase in the low emission scenario changes to the significant decrease in the medium and high emission scenario;The mid-latitudes of the Southern Hemisphere show a significant increasing trend under the low emission scenario,but the trend is not significant under the medium and high emission scenario.