Analysis On Climatic Factors And Desertification Evolution Trend In The Southeast Of Mu Us Sandland

In this paper,the typical area of land desertification development and management in northern China was selected as the study area.Using the data of temperature and precipitation in the study area from 2000 to 2014,remote sensing image in 2000,2004,2008 and 2012,and in 2000,2005 and 2010,the land use data shows that the evolution trend of desertification in the southeast of Mu Us sandland.Based on the Markov prediction model and the changes of desertification land in 2000 and 2012,the future desertification evolution trend of the study area is predicted,and reached the following conclusions:(1)From 2000 to 2012,the vegetation coverage change is not large in spatial distribution.In the temporal variation,low vegetation coverage,lower vegetation coverage,medium vegetation coverage and higher vegetation coverage showed a decreasing trend.The high vegetation coverage is increasing,and the growth rate is obvious.During 2000 to 2010,the changes of land-use types in the southeast of the Mu Us sand land as follows:the area of woodland,grassland and other land increased,while the area of cultivated land,water and sand land decreased year after year.Among the six land-use types,the land area transformed into grassland is the largest,and the land area transformed into sandy land is the smallest,which indicates that the land use in the study area is gradually rationalized,the vegetation cover is obviously increased,the desertification area is effectively controlled and the fragile ecological environment is improved.In the spatial distribution pattern,the land use types dynamic change is not large.Sandy land are distributed in the every county,but there is the most extensive sand land area in the Shenmu County and Yuyang District.(2)From 2000 to 2012,the areas of extremely severe desertification,severe desertification,moderate desertification and mild desertification have been shown a decreasing trend,while the potential land desertification area shows an increasing trend,and the growth rate is more obvious.In the desertified land,only 32984.96ha was converted to extremely severe desertification land,52098.54ha to severe desertification land,103141.57ha converted to moderate desertification land,304630.67ha converted to mild desertification land,and 904780.61ha converted to potential Desertification land.Spatial distribution pattern of changes in land desertification is:the extremely severe,severe and moderate land desertification is mainly distributed in the northwest part of Shenmu County,central and northern part of Yuyang District.The distribution of desertification in the mild and potential land is widespread,mainly exsits in the northwest part of Shenmu County,the central and north of Yuyang District.(3)The correlation coefficient between annual average NDVI and annual average temperature and annual average precipitation in the study area from 2000 to 2014,the correlation between the NDVI value and temperature is not significant.While the NDVI value and precipitation are showing growth trend,and there is a significant correlation between the NDVI value and precipitation.It can be seen,the precipitation has a significant effect on desertification.(4)The future development trend of desertification land is predicted by Markov model,and it is found that the area of the extremely severe desertification,severe desertification,moderate desertification and mild desertification area in the study area are declining during the forecast period,and Potential land desertification area is growing.Desertification land is in good condition,the reversal trend of land desertification is obvious,and the ecological environment of the area has been improved continuously.