| China suffers from the impact of land desertification,especially in the northwest region,where the situation is extremely severe.In recent years,due to the change of the natural environment and the government's emphasis on land desertification control,the area of land desertification in Qinghai Province has gradually decreased,but the situation of land desertification in some areas of Qinghai Province is still very serious.In this paper,the Rainfall Use Efficiency(RUE)was used as the monitoring index of land desertification in Qinghai province to analyze the changing trend and main influencing factors of land desertification in Qinghai province,so as to provide theoretical basis for ecological environment protection and prevention of land desertification prevention and control in Qinghai province.The main results are as follows:(1)The change periods of precipitation,humidity,sunshine hours and average wind speed in the past 20 years are 8a and 2a,and the temperature is 10 a and 4a.In the future,precipitation and humidity will continue to increase,and sunshine hours,average wind speed,and temperature will decrease or become shorter in the future.In the future,precipitation and humidity will continue to increase,while temperature,sunshine hours and average wind speed will decrease or shorten in the future.In the spatial change of climate factors,the precipitation in the northwest of Qinghai Province shows an increasing trend;the average temperature shows an increasing trend in the South and northeast of Qinghai Province;the average humidity decreases in some parts of the south of Qinghai Province,and increases in the West and north of Qinghai Province;the sunshine hours become significantly shorter in space;The average wind speed decreased significantly in the western part of Qinghai province and increased in the southern part of Qinghai province and some eastern parts of Qinghai province.most of the climate change remained stable.(2)The spatial distribution of RUE and NDVI in Qinghai Province is low in Northwest and high in southeast,gradually increasing from northwest to Southeast.The main accumulated NDVI in northwest is less than 0.75,accounting for 38%,and the corresponding value of RUE is less than 0.004.The accumulated NDVI in East and south of Qinghai Province is relatively high,accounting for 40% of above 1.5,and the corresponding value of RUE is more than 0.008.The northwest is mainly unused land and forest grassland.The RUE is relatively low in the west,which is mainly concentrated in the unused land.The RUE is relatively large in the East and south of Qinghai,and the land use types are mainly forest,grassland and cultivated land.(3)In terms of land desertification in different periods,the proportion of land desertification in Qinghai Province is 5.16% in 1999-2006,4.25% in 2006-2012,and 14.57% in 2012-2018.In terms of accumulation in different periods,the proportion of land desertification in 1999-2012 is 31.08%,which is 25.92% higher than that in 1999-2006,indicating that land desertification is increasing rapidly in this period.In 1999-2018,the proportion was 24.94%,which is 6.14% lower than that in 1999-2012,indicating that the trend of land desertification is slowing down.From the perspective of spatial changes,land desertification in Qinghai Province has shifted from the central and western regions to the northwest region.The provincial average of the Hurst index is 0.43,and its sustainability is not strong.(4)Temperature,sunshine duration and wind speed were positively correlated with rue value,accounting for 64.23%,91% and 73.48% respectively,and the proportion passing the significance test was 23.83%,60.66% and 31.62%,indicating that they had a certain inhibition effect on land desertification.The negative interference of human factors to rue accounted for 55.28%,which had a certain promoting effect on land desertification. |
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