Remote Sensing Based Hydrological Dynamic Analysis Of Lakes In Tibetan Plateau And Its Response To Climate Change

The environmental change of the Qinghai-Tibet Plateau plays an important role in responding to the changing climate of global warming.And lakes are indicators of global climate change.There are many lakes and various causes in the Qinghai-Xi za ng plateau area,and the environment is very rare due to human disturbances.Therefore,the dynamic changes of lakes in the Qinghai-Tibet Plateau record the water circulat io n process of the whole Qinghai-Tibet plateau and even the whole world,and the Change of Lake water volume reflects the dynamic development of water resources in the Qinghai-Tibet Plateau.Therefore,the analysis of the dynamic changes of hydrologic a l elements in the Qinghai-Tibet Plateau since 21st century is of great significance to the understanding of the climate change and the sustainable development of water resources in the Qinghai-Tibet Plateau.This study takes the whole Qinghai-Tibet Plateau as the research area,the research time period is from 2001 to 2016,using remote sensing product data,satellite altime tr y data to obtain the area information of 66 lakes and the water level information of 37lakes,and to analyze it in time and space;In order to further reflect the distribution of water resources in the whole Qinghai-Xizang plateau area,In this study,the method of remote sensing analysis of lake water quantity based on lake water level-area relation is proposed,taking 4 typical lakes as examples,they are:Qinghai Lake,color Forest fault,Eling Lake and multiple lattice wrong kernel fault,revealing the characterist ics of the annual and interannual Variation of Lake water volume in the study time limit;Finally,The climatic changes of the whole Qinghai-Xizang plateau were studied by meteorological data,and the driving factors of water change in typical lakes were analyzed.The main research results and conclusions are as follows:?1?Using the method of automatic extraction of water area in this paper,we can get the complete area time series data of the object,the time resolution is high and the influence of cloud in the lake area is higher.As a whole,the lake area was significa nt ly expanded between 2001 and 2016.The color forest fault and Qinghai Lake are in the rapid expansion stage in the research time,the expansion rate is+20.53 km²/a and+11.84 km²/a respectively,the sheep Yamdrok wrong lake area shrinks seriously.In terms of space,the Lake Group at the junction of Tibet and Qinghai Province in the hinterland of the Qinghai-Tibet Plateau is expanding faster;the coniferous forest and grassland area of the Qilian Alpine Basin in the northeast of China also shows a steady rising trend;the lake Dynamics in South Tibet is not very large,the sheep's Yamdrok is descending rapidly,and the lakes in Water level change is also the color forest wrong rising momentum is the most rapid,sheep Yamdrok the fastest decline.?2?In the result of simulating water change based on lake water level-area curve,it is found that four of lakes'water level-area fitting curve has a good effect,its R²reaches 0.83^**,0.74^**,0.77^**and 0.74^**respectively,and compares the annual simulated area with the lake area obtained by remote sensing method,the comparison results also show that the water level-area relationship is well fitted,but the better results of Qinghai Lake indicate that the lacustrine basins in Qinghai Lake are close to the inverted el iptical shape.According to the trend of annual change of water quantity,the amount of water in the study time is increased fastest and most,Eling Lake the fluctuation of the whole study time,but the water quantity also increased by 488 millio n m³.From the change of the year,the Four lakes in the year the most significant changes in the lake is the color of forest fault,and the multiple lattice of the wrong kernel of the year change the most gentle,generally in a stable whole or stable decline state.In addition,the relationship between the changes of lake water quantity and the results of previous studies is very good,which shows that the method based on remote sensing is very reliable.?3?Using the data from the 87 meteorological sites of the Qinghai-Tibet Plateau from 2001 to 2015 and the data of the high spatial and temporal resolution data sets of the Chinese region to analyze the climate change of the whole Qinghai-Xizang plateau,the study found that:within the time limit of the study,the temperature became significant and the precipitation With the increase of wind speed and temperature in most areas,the evaporation of the whole Qinghai-Xizang plateau is mainly in the growth stage.The changes of these climatic factors profoundly affect the water balance of the lake,change the distribution of aquatic resources in the Qinghai-Tibet Plateau,and have great influence on the Qinghai-Tibet plateau,the whole country and even the world.The lake surface of Qinghai Lake has the largest annual precipitation,and rises year by year.The precipitation of the lake is the smal est and the decreasing trend of the dogger,and it is the coldest area in four subjects.The temperature of the four lakes was not changed,and the annual precipitation and the wind speed of the lake were decreased year by year.By correlation analysis between meteorological elements and net income of lake water,it can be found that the increase of precipitation and the decrease of evaporation are the intrinsic factors of increasing water volume in lake area.But for the other three subjects,the lake wind speed has a great effect on the water balance,but the precipitation factor has little effect on the quantity and income of the three lakes.