Analysis Of Land Desertification Evolution In West Jilin Province Using 3S Technology

China is among the countries facing the most severe desertification problems in the word. Desertification is not only causing huge economic losses, but also harms the wellbeing of people. Thus, researches on desertification monitoring, causes and evolution process, especially the study of dynamic simulation and prediction, will have significance importance for desertification control and prevention.Firstly, ‘3S’ technology is utilized to extract the image of two periods(2002 vs 2013) with different degree of land desertification from Tongyu County. The images were used to analyze the dynamics and the evol ution of desertification; Secondly, meteorological, economic and social data of the past 10 year from Tongyu county in combination with statistics method were used to analyzed how climate and human activities cause desertification; Thirdly, elevation, slope and aspect information were extracted from the DEM data, and GIS spatial analysis was utilized to study the distribution of desertification in different elevation, slope and aspect. Finally, geographical cellular automata model(model is tailored to be suitable for Tongyu county with the help of C# and ArcEngine; ‘fuzzy comprehensive evaluation method’ was combined with ‘analytic hierarchy process’ to custom transformation rules) is used to simulate and predict the occurrence and development of desertification in Tongyu County. Based on the above research, the following results and conclusions were drawn:(1) From 2002 to 2013, the total area of desertified land in Tongyu County decreased from 2023.04km2 to 1162.74km2; Desertification land are mainly mild desertification and moderate desertification.(2)In 2002 and 2013, desertification lands are mainly reverse type(1434.1 km2), whose area are significantly greater than the developmental or stable type desertification area.(3)Over the last decades, precipitation and relative humidity of Tongyu County showed an increasing trend; Evaporation, temperature and strong wind days(and sandstorm days) tended to decrease; Number of large animals declined significantly-favorable changes in climate and the implementation of local policies is a key driver in reversing desertification.(4)More than 80% of desertification lands of different degrees are distributed between 150 m ~ 175 m above sea level, various types of desertification land are mainly in the slope gradient of less than 3 degrees, high plains and or northern slope.(5)It is known that the decreasing trend of desertification land area could be predicted in Tongyu county next few years and it is helpful to reduce the driving factor conditions according to the analysis of the driving factors of desertification and the results of cellular automata model for desertification evolution simulation in 2013.