Extraction And Spatio-temporal Evolution Of Thermokarst Ponds In The Beilu River Basin Of The Qinghai-Tibet Plateau

In recent decades,the Qinghai-Tibet Plateau has been subjected to a combination of climate warming and human activities that have led to the degradation of the permafrost,which in turn has led to the widespread occurrence of thermokarst ponds.The formation and evolution of thermite ponds is one of the important factors influencing the geomorphological reshaping of the plateau permafrost zone,regional ecological and hydrological changes,and important greenhouse gas emissions.In this paper,we study thermokarst ponds in the Beilu River Basin,a highly vulnerable area of the Qinghai-Tibetan Plateau,and use the high spatial resolution remote sensing images from 2003 and 2015 to automatic extraction of thermokarst ponds,as well as for classifying and detecting the changes in thermokarst ponds,and exploring the causes of the changes in thermokarst ponds and the feed-forward relationship between the evolution of thermokarst ponds and the ecological environment.The paper achieved the following results:(1)Based on the analysis of domestic and international research results,the water bodies in the high incidence areas of thermokarst ponds were identified as thermokarst ponds,which provided new ideas for thermokarst ponds extraction in the Qinghai-Tibet Plateau,saved the working time of thermokarst ponds extraction,and verified the validity of the extraction results by comparison with historical literature.(2)In order to characterize the changes in the thermokarst ponds,a spatio-temporal topology relationship was introduced to characterize the above changes,which was used as a theoretical basis to classify the changes in thermokarst ponds between 2003 and 2015.The occurrence of a large number of small lakes was found to be responsible for the surge in the number of thermokarst ponds in the Beilu River Basin,but an important factor in the increase in the total area of thermokarst ponds in the study area was the developmental expansion of the existing thermokarst ponds in 2003.Exploration of the causes of the different types of changes revealed that geomorphology and engineering construction were the main reasons for the different changes in these t thermokarst ponds.(3)The thickness of permafrost has an important influence on the evolution of thermokarst ponds.The thinner the permafrost,the more likely it is to lead to the formation and development of thermokarst ponds,and the thickness of permafrost can resist the evolution of thermokarst ponds after reaching a certain level.The simultaneous evolution of thermokarst ponds and ponds can in turn lead to new ecological problems,such as soil desertification.The fragile ecological environment is prone to the formation of thermoplastic lake ponds,which in turn exacerbates the degradation of the ecological environment.