| China’s northwest region is located in the depths of the mainland due to the lower average rainfall,while evaporation,coupled with rapid population growth to bring great pressure on the environment,making the human excessive reclamation grazing,etc.These factors combined effect caused by our northern Regional desertification area is expanding.For a long time,China has invested a lot of manpower and resources to carry out wind and sand fixation work,although it has achieved some success,but the overall situation of China’s desertification is still grim.The northern sand control belt is mainly distributed in the Inner Mongolia Autonomous Region,Gansu Province,Qinghai Province and Xinjiang Uygur Autonomous Region.It is an important part of the ecological security strategy pattern of "two screens and three zones",which plays an important role in maintaining our ecological security.In this study,the spatial and temporal variation characteristics of windbreak and sand balance in the northern sand control zone were studied by using the modified wind erosion model(RWEQ),and the influence factors of windbreak and sand fixation were analyzed.This paper explores the barrier effect of sandstorms in northern China in recent 30 years.The main conclusions are as follows:(1)The sand control capacity of the northern sand control zone is in the order of Inner Mongolia sand control barrier zone,Hexi corridor sand control barrier belt and Tarim sand control barrier belt.From 1982 to 2011,the overall trend of windbreak and sand fixation in Hexi Corridor sand control barrier is enhanced Trend,the sandy sandy sand barrier belt in central and Inner Mongolia sand barrier belt in the northeastern region of wind and sand sanding capacity showed a decreasing trend.(2)In the study of the ecosystem of the sandy barrier in the north,the vegetation coverage in the south of the Tarim sand control zone changed significantly,and the central NPP changed significantly.The vegetation coverage in the northwest area of the Hexi Corridor was significantly changed,and the leaf area index in the central region changed significantly.The vegetation coverage,NPP and leaf area index of Inner Mongolia sand control zone are distributed in the barrier area.Northern sand barrier with land use type 2000-2010 farmland net out of the highest area,most of the area out into a grass,shrub(3)Analyze the influence of land use change on the function of windbreak and sand fixation in the last ten years.It was found that the quality sequence of sand fixation land in the northern sand control zone was grassland> desert> farmland> shrub> bare land> forest land> Towns and grasslands are the main land use types that control the sand erosion in the north with wind erosion and play the role of wind and sand.(4)On the whole,the sand barrier in the north is in the low rank of vegetation cover and low vegetation cover.In the seven grades of vegetation cover change in the north.In the above area,the extent of vegetation cover change is negatively correlated with wind and sand fixation capacity.(5)Based on the "China Strong Sandstorm Storm Sequence and Its Supporting Data Set",the temporal and spatial variation of dust storm intensity in China from 1980 to 2007 is analyzed by using the inverse distance weight interpolation method.The results show that the areas with strong dust storm activity in northern China are concentrated in southern Xinjiang The southern edge of the basin,the Alxa Plateau region and the Xilin Gol League area in the northeast of Inner Mongolia.From the geographical point of view,the northern sand barrier zone is based on the green ecological security barrier near the dust source area.Strengthen the construction of ecological barrier in innermongolia. |
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