Preliminary Exploration And Application On A Coupled Dynamical Model Of Vegetation-Wind Erosion-Hydrology

Global desertification is a major ecological and environmental problem that has affected human survival and development since the 20 th century.Desertification refers to the phenomenon of land degradation in arid,semi-arid and sub-humid arid regions caused by natural climate variation and human activities and it's the main reason that restricts the economic development of arid and semi-arid areas.The sandstorm phenomenon accompanied by desertification will worsen the ecological environment,threaten human health and cause great economic losses to human society.There is also a reverse development process of desertification in the desert zone--oasisization.The increase of the oasis area is the result of the continuous growth and reproduction of vegetation,and there is a dynamic evolution process between the oasis and the desert.Previous studies on desertification and oasisization are independent of each other,and are generally carried out in three aspects: vegetation,wind erosion and soil moisture.Although the research on the evolution law between desert and oasis has been carried out,the current model does not fully establish the coupling mechanism of vegetation,wind erosion and hydrology,so it is difficult to accurately describe the dynamic evolution of desertification and oasis.Using vegetation coverage,wind erosion rate,moisture index as the three quantities to measure the development of vegetation,wind erosion and hydrology in the region,considering the coupling effect between the three and the influence of human activities on its development,vegetation-wind erosion-hydrology coupled dynamical model which has simple structure and clear physical meaning is established.When applied to Xilingol area,the model has a high accuracy in simulating the evolution of vegetation,wind erosion and hydrology in the process of desertification and oasisization,and the calculated value is in good agreement with the measured value.Meanwhile,this paper analyzes the status of vegetation,wind erosion and hydrological development in this region,and puts forward relevant suggestions on desertification control measures:(1)Unscientific artificial control measures may lead to the imbalance of hydrological development in the region and the regional drought.Later remedial measures reversed the development of hydrology.This shows that hydrology is an important index that cannot be ignored in desertification control.Desertification control requires comprehensive and scientific measures in vegetation,wind erosion and hydrology.In the process of desertification control,the deterioration of vegetation,wind erosion and hydrology in the region to a certain extent is repairable,and the reasonable artificial control method will get twice the result with half the effort.(2)Artificial control and human activities are the most important driving force for the development of desertification.Human production will inevitably cause the destruction to the ecological environment,accelerating the development of desertification.In the process of desertification,especially when the region is in an unstable state,lax governance and management may cause the region to return to the original vicious circle,which will make the previous efforts useless.Desertification control in a region is a long and tortuous process of development.In order to make the region to increase the oasis area,desert area to reduce the trend of development,it is necessary to persevere in human and material resources in the artificial control.