Study On The Area Change Of Major Lakes In China Based On Satellite Remote Sensing Images In Recent 30 Years

Lakes are an integral part of water resources,play an important role in the water cycle,and are also an indispensable resource for social and economic development.Due to climate change and the continuous strengthening of human activities,the area of lakes in my country has undergone significant changes.Previously,due to the limitation of traditional methods to deal with a large amount of remote sensing data and the influence of other factors,most domestic studies focused on the area changes of individual lakes or regional lakes,and there were few studies comprehensively exploring the changes in lake area across the country.The emergence of remote sensing cloud computing technology has changed the original research status.It can quickly process and analyze massive remote sensing data,reducing the difficulty of large-scale long-term series research.The shrinkage and expansion of lakes will affect the ecological functions of lakes and the sustainable development of regional economy.Exploring the changing trends and driving factors of lake area is the basis for the management and improvement of lake ecological environment,and can provide important scientific basis for the sustainable utilization of lake resources,ecological civilization construction and economic construction.This study is based on Google Earth Engine(GEE),using decision tree-based water body extraction methods,extracted water bodies from tens of thousands of Landsat series satellite remote sensing images from 1990 to 2020,and obtained 38lake areas in China's five largest lake regions.Unary linear regression method,Mann-Kendall trend test,Mann-Kendall mutation test,Pettitt test and Pearson correlation coefficient were used to analyze the change trend,visibility,mutation and related driving forces of lake area from 1990 to 2020.The research results show that:(1)Among the 38 lakes studied from 1990 to 2020,the lake area of the Yunnan-Guizhou Plateau Lake Region showed a downward trend(-0.97km2/a),the area of Wulungu lake(0.68km~2/a)in the Mengxin Plateau and Xingkai Lake(1990-2013:2.5km~2/a;2013-2020:29km~2/a)in the Northeast Plain and Mountain Lake Region showed an expansion trend;the lake area of the Eastern plain Lake Region fluctuated more violently.The area of lakes has shown a shrinking trend from1990 to 2010,and an expanding trend from 1990 to 2010;the area of Selincuo in the Qinghai-Tibet Plateau Lake Region expanded the fastest(26.37km~2/a,R~2=0.91).(2)Through correlation analysis,it is found that most of the lake area changes are positively correlated with annual precipitation,and negatively correlated with annual average temperature.The change of precipitation can directly affect the lake area.Compared with precipitation,temperature can indirectly affect the change of lake area.The increase of temperature causes the increase of lake evaporation,which leads to the shrinkage of lakes.However,there was a positive correlation between the area change of Selincuo in the Qinghai-Tibet Plateau Lake Region and the average annual temperature.The temperature promoted the expansion of the lake area,which was contrary to the above results.The overall correlation between lake area and annual precipitation in the Eastern Plains Lake Region is relatively low,especially the northern subtropical lakes.(3)Through the analysis of land use change,it was found that the cultivated area of the Yunnan-Guizhou Plateau lake area and the Eastern Plain Lake Region are gradually decreasing,the Qinghai-Tibet Plateau lake area(Selin Co,Yangzhuoyong Co),the area of cultivated land in the Northeast Plain and the mountainous lake area(Xingkai Lake)is expanding.The area of cultivated land is expanding.The Mengxin Plateau Lake District(Wulungu Lake),the Yunnan-Guizhou Plateau Lake District,and the Eastern Plain Lake District have expanded significantly for construction land,and the expansion of construction land has accelerated since 2000.Human activities in the eastern plain lake area are relatively strong,and construction land has expanded significantly and most of them are distributed around the lake.Enclosing lakes for fish farming,reclaiming land from lakes,and returning farmland to lakes have all had a greater impact on the lake area.