Study Of Stable Oxygen Isotope Feature In Tamarix Cone And Environmental Change In Andier Of Xinjiang During Past About 200 Years.

As an important composition of the earth surface system,the influence of desert's climate change on global ecosystem is remarkable.Taklimakan Desert is located in the Tarim Basin of southern Xinjiang,deeply in the inland,it is the desert farthest from the ocean in the world,its climate is dry with little rain,and strongly sandstorm activity.Tamarix with unique physiological structure under the harsh environment to survive,the sedimentary veins are formed by alternating deposition of litter layers and sand layers,contains a lot of environmental information,which can restore the past environmental changes.This paper with the help of a variety of dating methods to determine the decade of Tamarix cones located in two different sites in Southern region of Taklimakan Desert,extract the ?¹⁸O in Sedimentary veins,through correlation analysis,regression analysis and other methods of mathematical statistics,choose the appropriate proxy indicators,use kinds of proxy indicators and a single proxy indicator to restore various climatic elements,determine the most appropriate proxy indicator,combine meteorological data of Southern region of Taklimakan Desert to rebuild the climate change in this area for two hundred years,and compare with the existing research results.The main conclusions are:?1?Through the correlation analysis between ?¹⁸O and the monthly average temperature it is demonstrated that the?¹⁸O sequence of A sampling site has a significant negative correlation with the average temperature in February,September and annual.Control effect of temperature on the content of ?¹⁸O in the Tamarix is obvious,while the temperature in the Tamarix fiber decreased the content of oxygen isotope.?2?The ?¹⁸O sequence is negatively correlated with the average monthly and annual minimum temperature.The ?¹⁸O in August,November annual minimum temperature was 0.05 through the reliability test.?3??¹⁸O in March and from June to September was negatively related to the average monthly humidity,relative humidity between ?¹⁸O and November are more significant.In November ?¹⁸O and the average temperature,average minimum temperature has significant correlation,and the average temperature,average relative humidity was negatively correlated and positively correlated with the minimum temperature.?4?Through the correlation analysis between ?¹⁸O and the Sunshine hours it is demonstrated that the?¹⁸O sequence of A sampling site has a significant negative correlation with the sunshine hours in from January to May,September,November,December and annual.August through the reliability of 0.05 of the test.In August,the sunshine time is long,the relative humidity is low,the transpiration is intensified,the plant absorbs the water to increase,is advantageous to the photosynthesis,is advantageous for the oxygen isotope enrichment.?5?Study on correlation between?¹⁸O sequence and precipitation in red leaves showed that all month and annual precipitation were not through the reliability test of 0.05.But the number of sequences by moving average processing through the reliability test of 0.05 to add to 7,and the most of results are negative correlation.?6?The analysis shows that the sunshine hours of February regression ?¹⁸O series,the average temperature in November,the two climatic factors?Sunshine hours in February and the average temperature in November?on the value of ?¹⁸Oin tamarisk cellulose larger contribution can explain the changes of tamarisk fiber ?¹⁸O sequence of 33.6% leaves.?7?Through reconstruction annual average temperature of Andier area can know the two cold period from 1792 to 1822,from 1853 to 1914.Two a warm period from 1823 to 1852,from 1915 to 2010.?8?Through reconstruction July precipitation of Andier area,get two wet period from1792 to 1821,from 1846 to 1911.Two dry period from 1822 to 1845,from 1912 to 2010.