Study On Modern Climate Change And Environmental Response In The Southern Margin Of Tarim Basin,Xinjiang

Under the background of global warming,extreme catastrophic climate events occur constantly,and global change has become a hot topic in the world.In order to better understand the process of climate changing,the Southern Margin of Tarim Basin Region?SMTBR?was selected in this thesis.Referring to historical literature,consulting statistical yearbook,and based on modern apparatus measured meteorological data,using the climate reconstruction proxies preserved in the Tamarix Cone sedimentary veins,the characteristics of the climate change in the southern margin of Tarim Basin were analyzed synthetically.And then,the satellite remote sensing images were analyzed to further explore the response and its mechanism of environment to climate change in the area.First,the trend of climate change over the past 400 years has been reconstructed,according to the meteorological data from 1960 to 2011 measured by Qira,Qiemo,Ruoqiang weather stations and the data of grain-size of sand materials,C/N,positive ions,?¹³C,?¹⁸O,pollen assemblages preserved in Tamarix cone sedimentary veins in AMTBR.Combined with the data from National Meteorological Information Center and self-built automatic meteorological observatory of real-time data,the climate changing characters in SMTBR are analyzed.Steered by the westerlies,the precipitation increased,there is a marked increase in the minimum temperature,and sand effect is weakened.The inflection point of temperature appeared in 1996,while the inflection point of precipitation occurred in 1980s.Secondly,by analyzing the remote sensing images in 1990?±3 years?,2000?±2 years?,2010?±1 years?and 2015?±1 years?,it was found that the summer glacier area in the alpine region of SMTBR?above 5000m?showed a weak expansion trend.The growth of vegetation in midmountain?2000-5000m above sea level?is good,and the vegetation coverage area is obviously expanded.Alpine glaciers and midmountain vegetation are less affected by human,and the changing trend reflects the development of climate environment towards warm and wet.The area of the oasis in research area was expanded,and the development of the oasis showed a trend of radioactive expansion centering on source of water.Thirdly,based on the correlation analyses between the real-time,daily,monthly,annual,ten-year,thirty-year scales of meteorological elements,meteorological elements and soil moisture,meteorological elements and the climate proxies preserved in Tamarix cone sedimentary veins,the driving mechanism of environmental change in SMTBR was found:The solar radiation is the driving factor of daily,monthly change of temperature,higher concentration of CO₂ in the atmosphere resulted by human activities is the main cause of temperature-rising.As the temperature rises,the vegetation in the front spring overflow zone can obtain more available water and promote environmental changes.Temperature is the main limiting factor of vegetation growth in desert regions controlled by human activities.Water resource is the decisive factor of environmental change,while air temperature is the main driving factor of environmental change.This thesis takes the southern margin of Tarim basin as the whole research object for the first time,and analyzes the changing characteristics of regional glaciers,midmountain vegetation and oasis comprehensively.It is found that the ecological environment experienced a transformation process from deterioration to improvement.Integrating the results reconstructed by grain-size of sand materials,C/N,positive ions,?¹³C,?¹⁸O,pollen assemblages preserved in Tamarix cone,it can be concluded that the regional temperature rose with rising global temperatures.Then,through the analysis of the real-time dense data of the self-built meteorological observation station,the high correlation between the shallow soil moisture and the atmospheric temperature is obtained,which prove that the temperature is the driving factor for the improvement of regional water resources conditions.Finally,according to the correlation analysis of four different scales of data on water resources,environmental factors,climatic factors and human activities,it is confirmed that human activities are the fundamental cause of global warming,and it is found that regional moisture increase caused by temperature rise can improve the response mechanism of ecological environment.