Study On The Temporal And Spatial Dynamic Change Of Kubuqi Desert Oasis Based On Remote Landsat Image

Oasis,as the core place of human survival and production in arid area,its development stability will be directly related to the sustainable development of regional social economy.Kubuqi Desert is one of the fragile areas of ecological environment in China.People's continuous development of resources in arid areas,on the one hand,brings more living space,but on the other hand,it may also cause other ecological problems.Therefore,the study of the temporal and spatial change process of Kubuqi Desert oasis can provide scientific basis for the rational development of oasis.In this paper,seven Landsat TM/oli images of Kubuqi Desert in Hangjinqi section from 1991 to 2019 were used.Based on ENVI 5.3,ArcGIS 10.2 and Fragstats 4.2 software,the information of Hangjinqi section of Kubuqi Desert Oasis was extracted by the method of supervised classification and manual visual interpretation.The temporal,spatial and landscape pattern changes of Kubuqi Desert Oasis in different periods were analyzed.The main conclusions were as follows:(1)According to the characteristics of oasis change in time series,the dynamic change of Oasis in 1991-2019 was divided into three stages:steady development period(1991-2000),short contraction period(2000-2004),rapid expansion period(2004-2019).(2)According to the change characteristics of oasis in spatial sequence,we can see that,Oasis was dominated by stable regions,expansion and contraction coexist in each stage,and the extent of expansion varies,but the overall trend was expansion.The area of stable and unchangeable oasis was the largest and most widely distributed.The second was the continuous expansion type oasis,and a few in the interior of the stable and unstable oasis of the intermittently fluctuating oases were distributed in the desert oasis transitional zone in the west of the desert.In the past 28 years,the center of gravity of oasis had shifted eastward,with a straight-line migration of 6.36km.The transformation between forest,grassland and sandy land was the most obvious.Frequent conversion among forest,grassland,cultivated land and water area.The salinization of cultivated land in the study area was not serious.and a small amount of sandy land has also been developed as construction land.(3)From the landscape level pattern change,the fragmentation degree of oasis tends to decline,the spatial structure was becoming simple,the patch shape was becoming regular,and the landscape pattern was gradually developing from the diversified landscape types to the single landscape type,and the overall landscape pattern tends to be uniform.From the perspective of pattern change of type level,the fragmentation degree of forest and grassland was reduced,and the fragmentary patches were integrated into the large patches;the aggregation degree of water area was increased;the patch density of cultivated land,other unused land and construction land was increased,and the fragmentation degree was increased;the shape of each land use type patch in Oasis Changes frequently,but the shape was relatively simple in general.