| With the advancement of Hami’s leapfrog development,especially the rapid advancement of new industries based on resource development,and the further deepening of new urbanization,human demand for land had increased.In addition,due to the limited availability of land under the background of arid areas,Reclamation of large artificial oasis,this process had led to a decrease in the quality of the ecological environment and increased conflicts in land use.To this end,it was necessary to quickly monitor the quality of the ecological environment and evaluated the capacity of the ecological environment.Remote sensing is widely used as a technology with advantages such as fast access,low cost,and wide monitoring range.Therefore,this paper used remote sensing data to monitor the surface environment of Yizhou District,Hami City,and evaluated its ecological environment quality at the same time.The following conclusions:1)The overall growth trend of vegetation coverage in the three periods,but the area of low coverage areas exceeded 50%,accounting for the main share.The change in vegetation coverage was mainly the transition from low coverage areas to higher coverage areas,and low coverage areas became the main source of the expansion of Hami’s ecological environment quality.The surface humidity had the largest proportion of the overall lower humidity range in the three time periods,but with the change of time,the area of the low-grade and lower-grade ranges was decreasing,and they were mainly concentrated in the northwest and southeast regions,while the medium-high humidity and the area of high humidity range showed an increasing trend,and the change was significant.The overall high dryness range accounted for the largest proportion in the three time periods of surface dryness and all exceeded 67%.The change trend showed a slow increase after a decrease.The low dryness,low dryness,medium-high dryness and high dryness regions shifted more.Small,the transfer-out area accounts for less than 10%,and the medium-dryness transfer-out area exceeds 50%.The overall change in the surface dryness in the study area was small,and the transfer between the various dryness grades was not obvious.The land surface temperature accounted for the largest proportion of the total area of high temperature and mediumhigh temperature in the three time periods,mainly in the northwest and southeast regions,but with the change of time,the overall area was decreasing.2)From 2000 to 2018,the green degree and humidity of Hami eco-environmental quality had a positive correlation with RSEI,while the heat degree and dry degree had a negative correlation with RSEI.Within the study area,RESI showed an increasing trend,with the average values of 0.223,0.313 and 0.396 respectively.The overall level of ecological quality in the study area was not high,and it showed an increasing trend in the study time,which had a great role in promoting the oasis human settlements in the arid area;in 2000,Hami’s eco-environmental quality was medium,good and excellent,and the distribution was concentrated on the southeast northwest axis,which was consistent with the distribution of main oases,towns and farms.The areas with extremely poor and poor eco-environmental quality were widely distributed,mainly in the northeast corner and southwest region;in 2008,the areas with extremely poor and poor eco-environmental quality decreased significantly,while the areas with medium,good and excellent eco-environmental quality increased greatly,and the overall ecoenvironmental quality of Hami expanded rapidly;in 2018,the eco-environmental quality of Hami was unstable,and the eco-environmental quality was moderate The results showed that the oasis ecological environment was relatively fragile in the process of rapid urban expansion and land use changed.3)From the inside to the outside of the city,there was a similar ring mosaic.In2000,the order of ecological environment quality from inside to outside was high value area low value area high value area low value area;in 2008 and 2018,the opposite situation appeared.From 2000 to 2018,the areas with poor to excellent ecological environment quality turned to better ecological level.The overall ecological quality of the study area was improving,and the ecological land expanded rapidly.The direction of the major axis of the standard deviation ellipse in the three time periods was basically the same,indicated that the direction of RSEI and urban ecological environment quality expansion in Yizhou District of Hami City in the past 18 years was southeast-northwest,which was the same as the surrounding urban core area.The expansion of artificial oasis and the distribution of main railway and national highways in the same direction.Analyzed from the moving window,the changes in the periphery of the oasis in 2000 and 2008 were more dramatic than in 2018,and the trend of the expansion of the quality of the oasis’ s ecological environment was more obvious.The spread index and the diversity index of the oasis marginal zone were higher than other regions,indicated that the oasis marginal zone had the highest degree of fragmentation and significant diversity. |
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