Dynamic Assessment of Ecological and Environmental Quality in the Source Region of the Yellow River(Maqu)in Recent 20 Years
The source region of the Yellow River(Maqu)is an important water conservation area and re-charge area of the upper reaches of the river,which plays an important role in maintaining regional biodi-versity,ecosystem balance and socio-economic high-quality development.In order to reveal the dynamic change characteristics and regional differences of alpine grassland ecosystem in the past 20 years,based on Landsat 5,7 and 8 data sets obtained by Google earth engine(GEE),the remote sensing ecological index evaluation model and the single regression trend line method were used to analyze the dynamic change characteristics of the vegetations in Maqu.The results showed that 1)the average contribution rates of the 4 indices,including greenness(normalized difference vegetation index,NDVI),humidity(WET),heat(land surface temperate,LST),and dryness(normalized difference snow index,NDSI)on the first principal component were reached to more than 90%,and it was feasible to construct RSEI(remote sensing ecosys-tem index)to evaluate the ecological environment quality in Maqu County in recent 20 years.2)The vege-tation coverage in Maqu County was mainly increasing from 2000 to 2021,and the area with high vegetation coverage in 2021 accounted for 93.44%of the research area.The area of significant improvement of vegeta-tion coverage was mainly distributed in the large area between three townships(Qihama,Cairima,and Manrima)and the main stream of the Yellow River in the southeast edge of Maqu County,with an area of 4 458.9 km2,accounting for 38.36%of the county's land area.3)The RSEI of Maqu County from 2000 to 2021 showed an overall upward trend,with an increment of 0.047,and an annual average of 0.788,indica-ting that the overall ecological quality of Maqu County is at a good level.4)In the past 22 years,the ecological en-vironment quality of Maqu County showed a change characteristic of first degradation and then improvement.
万方数据
维普
