Study Of Stable Oxygen Isotopes Feature In Tamarix Cone And Environmental Change In Cele Region Of Xinjiang During Past About 400 Years

Cele oasis is located in the middle part of southern margin of Taklimakan Desert?35�17?³9�30?N,80�03?⁸2�10?E?,with its average elevation of 1380 m.The climate type there is the typical warm temperate desert climate,with little rainfall but high evaporation.The time of sunshine is long and the amount of light is abundant,while the temperature difference between day and night is very large.In Spring and Summer,strong wind blows heavily there and it comes with more frequent sandstorms.The hot dry weather often appears in Spring and Summer,accompanied with strong,frequent sandstorm activity.The typical soil mainly consists of brown desert soil,sandy soil and dry soils.The vegetation in this region is extremely poor,and the vegetation community types are drab and single.According to the research of the environmental change of the southern region of Taklimakan desert,it will help a lot with the environment changes in Xinjiang,even the entire arid areas' environment.Tamarix sediment veins formed by alternating deposition of litter layers and sand layers can not only be used as an effective mean of counting the years,but also contains a large number of climate and environmental information.Therefore,we can make use of Tamarix cone sedimentary veins to explore and century scale climate changes to restore the desert,thus making it an ideal carrier to study the climate change in arid area.In this paper,the Tamarix Cone is the main object of study.Moving average method is used in this paper to pretreat the data of ?¹⁸O values in order to obtain ?¹⁸O_ma sequence.And then this paper will further analyze the relationship of Tamarix cone stable oxygen isotope with climate change.On the basis of the analysis,the reconstruction of the climatic elements on a centennial scale was restored in a quantitative way.And the main process and conclusions are as follows:?1?The response of ?¹⁸O_ma to mean air temperature is not obvious,and the direction is inconsistent.It is speculated that the change of temperature may not play a leading role in ?¹⁸O.But this is consistent with the relationship between Tree Ring?¹⁸O and temperature in arid area.When the temperature is above or below a critical temperature,When the temperature is above or below a critical temperature,?¹⁸O shows different changes show different changes.?2?The sensitivity of ?¹⁸O_ma to monthly mean minimum temperature is very low.It can be inferred that the ?¹⁸O_ma in the study area may be independent of other climatic factors,resulting in an average minimum temperature signal and its weak.?3?The correlation analysis showed that there is a significant positive correlation between ?¹⁸O_ma and air relative humidity from April to December?except November?.It can be inferred that the influence of air relative humidity on ?¹⁸O_ma is very obvious.?4?The correlation between ?¹⁸O_ma and precipitation is significant in February,March,August and September.But the number of precipitation growth does not play a decisive role on the growth of Tamarix in cele that the average annual precipitation is only 38.64 mm and the evaporation can reach 2595.3 mm.Its growth is more depend on groundwater,and affected by the river water,soil moisture and other factors.?5?There is a significant negative correlation between the oxygen isotope and sunshine hours in autumn which.sunshine time is long.?6?Through the reconstruction of the average temperature in April in Cele area,we can get two cold periods and two warm periods.The cold periods are from 1724 to1790 and from 1900 to 2009.Warm periods are from 1670 to 1723 and from 1791 to1899.Through the reconstruction of precipitation in August in Cele area,we can get two dry periods and two wet periods.The dry periods are from 1635 to 1723 and from1792 to 1899 years.The wet periods are from 1724 to 1791 and from 1900 to 2009.