Analysing The Dynamic Change Of Main Saline Lake Area And Its Response Relationship To Climate Based On RS And GIS Technology

This paper is based on the 115 Landsat TM and ETM remote sensing images of five periods from 1972 to 2013 as the source of data,combined with the field investigations and indoor remote sensing interpretation and analysis,to research the dynamic change trend of the main Saline Lake in Xinjiang region.In this paper,the dynamic change of Saline Lake area is analyzed correspondingly through the meteorological data in the study area,to explore the correlation between the change of Saline Lake area and climate change in different Saline Lake area,and try to discuss the influence mechanism of climate change and human activities on the dynamic changes of Saline Lake in Xinjiang area,to analyze the dynamic change of the main Saline Lake water area in Xinjiang area and to provide reference for the development of Saline Lake resources.Firstly,remote sensing image is pre-processed,based on systematically collected the geological structure features of the Xinjiang region,regional climate,Salt Lake distribution,salt lake exploitation status and the meteorological data of stations in Xinjiang area.Then we analyzed the spectral characteristics of Saline Lake,Salt Pans and other typical features in remote sensing image through the topographic maps,topographic maps,field investigation data and other data sources,to determine the optimal band combination to extract the required information,to build remote sensing interpretation signs of Saline Lake.Finally,we use envi4.5 software to carry out human-computer interactive interpretation,and combine with the field data of field investigation,to determine the information of main Saline Lake and salt feature in images.In addition,we use the GIS technology to extract edge information of the Saline Lake and Salt Pans,and draw the change diagram of each Saline Lake in five periods.Through a discussion of the response relationship between the climate and the area of 32 Saline Lake in Xinjiang area during the past 40 years,the results show that:(1)Saline Lake that has not been affected by human activities is continuously increasing during the period studied,and the total area has been increased by 945.48km2.On the contrary,Although Saline Lake that has been affected by human activities has been expanded from 1992 to 2002,reduced the by 137.16km2 in the overall period;(2)Each change in the Salt Lake area is different.It is concluded that no human activities affect the Salt Lake is increasing except the few Saline Lake through the Arcgis10.0 analysis the vector of Saline Lake area in different periods.On the other hand,Saline Lake that has been affected by human activities has a narrowing of different degree in the study period except the two Saline Lake;(3)Area of Saline Lake and climate change is very large in different regions.Due to time and data constraints,in this paper,the correlation coefficient is calculated from three aspects of precipitation,annual mean air temperature and relative humidity,and analyze the influence of different climatic conditions on the area of Saline Lake,the average temperature and precipitation of which have an effect on the area of Saline Lake is different in different regions.Specifically,the Saline Lake area of the Tianshan Mountain has a strong correlation with the precipitation.The Saline Lake area increases with the increase of precipitation.The main reason is that the Saline Lake water in Tianshan Mountain is suppliedalmost comes from a nearby river.The increase or decrease of precipitation will directly affect the runoff of the river,thus affecting the amount of water in the Saline Lake area.However,there was no obvious correlation between the precipitation in Kunlun Mountain and Altun Mountain,Altai Mountain Saline Lake and the area of Saline Lake.The main reason is that the main source of water supply in the Saline Lake area is not a river.Rivers of Mountain are not rich around the Saline Lake.In addition,the precipitation in this region is relatively small,so it has little influence on the area of the Saline Lake.The area of Saline Lake in Kunlun Mountain and Altun Mountain is the most significant changes for the response relationship of the average temperature.This is because the Kunlun Mountain and Altun Mountain was covered a large amount of the ice and snow.Thechanges of temperature caused the alterations to glacier and snow runoff in the high mountain.But the glacier and snow runoff is not rich in the other two Lake area,and the increase of temperature leads to the increase of evaporation.So,the response relationship is weak.All of the correlation between average relative humidity and Saline Lake area in different regions is consistent.The increase in temperature may affect the increase of evaporation,and the shrinking of water area of Saline Lake.The average relative humidity can reflect the amount of evaporation.Therefore,the average relative humidity affects the area of Saline Lake by the change of the evaporation intensity.