Dynamic Monitoring And Driving Force Analysis Of Desertification In Jitai Basin

Now days,Land Desertification has became the most serious environmental problems,and it has attracted wide attention from all walks of life due to its deterioration rate and catastrophic nature.Carrying out research on the driving factors of desertification and its action mechanisms,especially quantitative research,is of great significance to the prevention and control of desertification.The desertification in the humid regions of southern China is becoming increasingly serious,and it is mostly distributed in remote areas with low economic levels.Traditional methods are difficult to monitor,the scope of investigation is small,and the timeliness is poor.Remote sensing technology has gradually become an important technical method for land desertification monitoring due to its advantages of comprehensive information,wide range,and small restrictions on human and material resources.In this paper,the red layer of the Jitai Basin is used as an object.Using remote sensing technology combined with field surveys and indoor analysis,the desertification in the Jitai Basin is monitored dynamically.Meteorological,human factors,formation lithology,and terrain slope are used to construct Jitai.The driving force analysis system of desertification in the basin and its influencing factors.(1)The Yongyang secondary basin on the west side of the Jitai Basin is one of the regions where desertification is heavy.Taking Yongyang Basin as an example,the band combination of remote sensing data suitable for red desertification information extraction is band654,band653,band651,and band754,and the best image fusion method is Gram Schmidt transform.Based on the characteristics of remote sensing images and field investigation and verification,Using the band combination method to synthesize the false color image,after image fusion,the red desert resolving translation mark is proposed.In terms of extraction methods,this study believes that the extraction method of desertification information can be selected according to the size of the scope.When the research area is small,such as the yongyang sub basin,the visual interpretation method is the best,while the Jitai basin with a large research scope can be applied to multiple index quantitative inversion methods such as the desertification difference index(DDI).In addition,using the trend analysis method to monitor the spatiotemporal change trend of desertification in the study area,the study shows that the desertification area decreased from 2003 to 2013,the vegetation coverage increased year by year,and increased greatly from 2008 to 2013,but the desertification area increased from 2013 to 2018.(2)The analysis of the driving factors of desertification shows that the influence of precipitation and human factors on desertification is double-sided.On the one hand,the increase of precipitation is conducive to vegetation growth,reducing the area of desertification,on the other hand,a large amount of precipitation is likely to lead to the intensification of soil erosion and desertification in some areas,which aggravates the desertification.Human activities in urban areas are negatively related to desertification,and desertification tends to decrease,while cities are Because of the unreasonable economic activities of human beings,the desertification in the marginal areas is intensified.(3)According to the field stratigraphic survey,the desertification is mainly developed in the exposed areas of sandstone,siltstone and reticulated laterite,the red bed desert with exposed bedrock is mainly developed in the upper Cretaceous sandy conglomerate system,the inferior red bed desert is developed in the Cretaceous and Quaternary strata,while the laterite desert is developed in the Quaternary strata.The sandstones and siltstones are the main parent rocks in the desertification area,and the sandstones and siltstones in the study area are the key factors for the development of red desertification.(4)The factor analysis of terrain slope shows that the higher the slope grade is,the higher the incidence of desertification is.The main part of the surface slope in Jitai basin is below 30 °,but the change of the surface slope grade and gradient in the north of the basin is larger than that in the south,and the desertification is also developed in the area where the surface slope is large or concentrated.The red desertification of yongyang basin in the northwest of China is mainly distributed in five grades of < 1 °,1 ～ 5 °,5 ～10 °,10 ～ 20 °,20 ～ 30 °,and the distribution is relatively concentrated.The overall fluctuation of the southern surface slope is relatively small,and the desertification is mainly concentrated in 1-5 °and 5-10 °levels,and in the form of scattered star point.