Correlation Between Desertification And Climate Change In Lake District In Gonghe County

Qinghai Lake District in Gonghe County is selected as the study area in this paper.Based on the climate data from 1960 to 2015 and the remote sensing image data from 1987 to 2015,the desertification land change information nearly 29 years in study area was extracted by using the ENVI software and Arcgis softwar in this article,and the changes of climate in the past 56 years and the desertification types in recent 29 years in Gonghe County was analyzed based on the linear trend analysis,the Mann-Kendall mutation test and the wavelet cycle analysis.Then,the internal relations of climate change and desertification in Gonghe County were explored from three aspects:spatial correlation,linear correlation and overall contribution rate,and the trend of desertification change in the basin of Gonghe County in the next few decades were predicted.The results are as follows:(1)In the past 29 years,the average annual value of desertification area in the basin area of the Gonghe County is 1335.37 km2,which is mainly distributed in the desert area adjacent to the Haiyan County,south of the Buha River Basin,the Daotang river basin,north of the G109 highway and the north side of the Qinghai South Mountain.The mild desertification and moderate desertification area showed a slight increase trend,the increase rate was the 2.22km 2/10a and the 1.446km2/10a.The severe desertification area showed a significant increase trend,and the expansion rate of 4.42km 2/10a.The sudden changes year of different types of desertification is concentrated around 2000.(2)In the past 56 years,the temperature of the Gonghe County has been increasing,the precipitation with a fluctuating fluctuation,and the humidity,the sunshine,the wind speed and the evaporation have a decreasing trend.The high temperature and rainfall are mainly concentrated in 7-8 months.The highest evaporation in summer,the highest humidity in September,the highest sunshine hours and wind speed are in spring.The period of the mean minimum temperature,the precipitation,the humidity and the sunshine are mainly 2a?4a.(3)The area which have significant positive correlation or negative correlation between the desertification and the average temperature in the study area,were account for 11.17%and 4.31%of the total area respectively.The area which has a positive correlation with the precipitation is about 82.17%.The area which has a significant positive correlation with the average relative humidity is 791.9 km2.The land is negatively with the sunshine hours about 82.1%.The land which has positive correlation or negative correlation with the wind speed was 48.58%and 51.42%,respectively.The area which was negative with the small-scale evaporation accounted for 73.31%of the total area.(4)The correlation analysis of desertification and climate change in the area shows that the average relative humidity has a significant negative correlation with the other desertification types except heavy desertification.The evaporation has a greater impact on mild and moderate desertification.The temperature has a greater impact on heavy desertification.The precipitation has an obvious impact on the mild desertification.The wind speed has an obvious impact on on heavy desertification.(5)The fitting curve of the comprehensive index of climate change has a similarity with the actual curve about desertification in the study area,and the contribution rate of the comprehensive index of climate change to the total area of desertification is 20.7%.The results of linear prediction of desertification area indicate that the area of mild desertification is gradually expanding,the area of moderate desertification and the severe desertification is decreasing,and the total area of desertification is increasing first and then decreasing.