Wind Erosion Assessment And Sand Retention Service Flow Research In Northwest China From 1980 To 2015

Wind erosion is an important cause of land degradation and desertification in the arid and semi-arid regions of northwest China,which seriously threatens national ecological security and human sustainable development.Therefore,the sand fixation service of the ecosystem is crucial to the construction of ecological civilization.Here,we quantitatively evaluated Wind erosion in the northwest region,and analyzed its spatial and temporal distribution pattern and variation characteristics.In addition,we explored the causes and influencing factors of Wind erosion changes.At the same time,the service flow direction and flow rate among sand-fixing service flow supply area and demand area distribution were quantified and mapped to provide basis for ecological function zoning,construction and management.This study provides a reference for national ecological security constructionIn this study,the soil,wind erosion status,and its spatial and temporal distribution characteristics were quantitatively evaluated in northwest China from 1980 to 2015 based on modified Wind erosion model(RWEQ)with ArcGIS10.2 and MATLAB under the climatic factors,vegetation indicators,topographical factors and soil properties.In addition,we explored the effects of temperature precipitation,vegetation index,and human activities on the changes of wind and sand fixation functions,and conducted preliminary research and cartographic research on ecosystem sand fixation service flows.The main conclusions are as follows:(1)The situation of Wind erosion in northwest China is still grim.In 2015,the strong,extremely intense and severe wind erosion area in the northwest region accounted for 38.45%of the total area,moderate wind erosion accounted for 17.38%,and mild and slightly erosion accounted for 43.67%.Strong wind erosion mainly occurs in the Taklimakan Desert,the Gurbantun Desert,the Kumutak Desert,the Alxa Zuoqi and the Alxa Right Banner.(2)From 1980 to 2015,the area of slightly wind erosion decreased by 7.88×10~2 km~2,the area of mild wind erosion in the study area increased by 7.3756×10~4 km~2,the area of strong and extremely strong wind erosion increased by 7.541×10~3 km~2,and the area of severe wind erosion increased by1.0961×10~4 km~2.Among them,85%of the slightly wind erosion area is converted to mild wind erosion;40.87%of the moderate erosion area is converted to mild erosion,the area is 1.93062×10~5 km~2;30%strong erosion turns to mild wind erosion;39.46%extremely strong wind erosion changed into severe erosion,8.45%turned into mild erosion;6.54%severe wind erosion converted into extremely strong wind erosion.(3)Analysis of influencing factors of Wind erosion showed that the meteorological factors in the study area were positively correlated with Wind erosion;the normalized vegetation index was negatively correlated with Wind erosion;the net primary productivity of vegetation and Wind erosion were mainly negatively correlated in the central and eastern parts of the study area,and positively correlated in the western part of the study area.Overall,the wind erosion condition in the nature reserve had improved,but the wind erosion intensity in some nature reserves had also increased.(4)The sand retention service supply area was mainly distributed in forest land and grassland.The supply rate of the supply area in the southeastern part of Xilin Gol League and Chifeng area was higher than that of the Tianshan Mountains and the Altai Mountains.the Tarim Basin,western Inner Mongolia,Chifeng and its surrounding areas were the main areas for sand fixation services,and the demand in desert areas was higher than other regions.The flow direction and flow rate of the wind-proof and sand-fixing service were mainly determined by the wind speed and direction,and the flow rate was evaluated by the RWEQ model.