| The spatial distribution of water resources in the Mu Us Sandy Land is extremely unbalanced,and surface water is very important to local economic development and ecological protection in Mu Us Sandy Land.The spatial-temporal changes of surface water in the middle areas of Mu Us Sandy Land were analyzed by using multi-source remote sensing images from 1999 to 2015.The boundary of water body were extracted by combining the best threshold of OTSU algorithm and binary B component images(based on LBV transformation).Considering the characteristics of climatic and industrial structure of the Mu Us Sandy Land,there are nine driving factors including the natural factors(precipitation,temperature)and the human factors(population,total industrial outputs,total agricultural outputs,number of small livestock,effective irrigated areas,raw coal production,and crude oil production)which affect the area changes of surface water were selected,and some human driving factors were downscaled to grid by using DMSP/OLS nighttime light data.The grey correlation method and the principal component analysis method were used to quantitatively measure the contribution of each factors on water area change.The main results include:(1)The surface water shrunk about 19%from 1999 to 2015 in Mu Us Sandy Land,the fluctuation range gradually decreased.The area annual variation was in the range of 3.18km~2 to 90.47 km~2,and the annual change was fluctuated between 1.2%and 35.82%,the annual changes of water body were complex and intense.The surface water area change is mainly influenced by natural(37.38%)and human factors(59.32%)changes.Among these9 factors,the highest contribution was air temperature(21.82%),followed by precipitation(15.55%).The contribution of human driver factors were ranked as follows:crude oil production(15.26%),effective irrigation area(15.03%),population(14.72%),and small livestock(14.32%).(2)The various human driving factors in Mu Us Sandy Land showed a significant(atɑ=0.05)growth trend,the population increased by 62.14%,and the population density in the entire study area increased from 17 persons/km~2 to 27 persons/km~2;The amounted of industrial output value increased by 38.89 times;The output of raw coal increased by 38.89times;The annual output of crude oil increased by 17.29 times;The total agricultural output value increased by 19.41 times;The number of small livestock increased by 4.01 times.The effective irrigated area had reached 2.7 times.The significant increase of these factors probably led to increased water consumption,which has indirectly impact on the area changes of surface water in Mu Us Sandy Land.(3)The driving factors were varied in each sub-region of the study area.Then the study area were divided into three parts:north,middle,and south by the different population density and natural characteristics.The change of surface water in the northern part was caused by natural(57.18%)and human factors(41.22%),with the highest contribution by precipitation(31.53%).The contribution of human factors come from changes of raw coal production and population(20.67%,20.55%).The main driving factors for the change of surface water body in the middle area are relatively complex.Among them,the highest contribution come from increase of raw coal production by 18.43%,and the contribution of temperature and precipitation were 17.42%and 13.16%,respectively.The surface water changes in the southern part of the study area were mainly caused by human factors(60.54%),and the natural factors accounted for only 32.43%.The contribution of agricultural driving factors reached 37.2%.The change surface water area is not simply proportional to the population density,it is highly related to the water resources management in each sub-region,indicates that the precise water management is very important in Mu Us Sandy Land.(4)The driving factor analysis of the typical lakes also proved that the great influence of the different water management measures.The Chagan Lake is nearly stable with small fluctuation under the strictest water protect policy,while the area of some typical lacks without regulation are significantly reduced.It is suggested that effective water resource management should be established and the water quota red line should be stipulated in the Mu Us Sandy Land.To maintain the stability of the water resources in this area,at the north and middle part of the study area,strict implementation of the monitoring policy for coal mining under water-containing shall be implemented,water-saving irrigation policy should be spread in the south part of the study area.The mechanisms of change need to be developed for the shrinking lakes,in order to carry out the water conservation and project management measures,such as the Hongjian Lake,the Subei Lake,etc. |
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