A Study On Climate Change And Its Response To Vegetation Coverage Change In The Eastern Xinjiang Region

Based on the data of air temperature and precipitation from 1960-2016 and Mod13Q1 from 2000-2016 in the region of eastern Xinjiang,the essay adopts the method of linear regression,accumulative anomaly statistics,signal-to-noise ratio,maximum value composite and wavelet analysis to study the characteristics of climate change and dynamic change of vegetation coverage in eastern Xinjiang? It is studied that vegetation coverage has a connection with the response of the correlation and lag of meteorological factors,this provides a reference basis for carrying out local greening work,rational utilization of land resources,protection of biodiversity,study of local climate evolution,and selection of development direction according to local conditions.The results indicate that:The average temperature in the eastern Xinjiang region has an increasing trend in general?The annual average temperatures in Turpan and Hami are 12.11 and 7.35 respectively ? The average annual temperature in Eastern Xinjiang declined in the1970 s and has been rising since the 1980 s ? The average temperature in spring,summer,autumn and winter is rising?The warming rate in Turpan was the highest in winter while the warming rate in Hami was the highest in autumn.There was a 3-18 periodic change in temperature ? There were seven alternating warmth and cold events?The annual average temperature in Turpan changed abruptly in 1986,while the abrupt change of annual average temperature in Hami happened in 1996?The highest and lowest temperature in the east of Xinjiang has the trend of warming up?The highest temperature in the four seasons is rising,and in autumn the highest temperature increases fastest ? There is no obvious abrupt change year of maximum temperature in Turpan?The lowest temperature in four seasons continues to rise?The fastest rising rate of minimum temperature is in winter of Turpan?The lowest temperature in autumn rises fastest in Hami?The year of abrupt change of minimum temperature in Turpan and Hami is 1986 and 1996?The highest and lowest temperatures in the east of Xinjiang have 7 oscillations and the main change cycle isabout 9 years?The precipitation in eastern Xinjiang increases with the average annual precipitation of 32.15 mm and 78.49 mm in Turpan and Hami?The annual precipitation in Turpan and Hami increased from 1960 s to 1990 s,decreased in the first decade of the 21 st century and increased in the first six years of the second decade of the 21 st century?The precipitation in the four seasons of Eastern Xinjiang shows an increasing trend,in which the rising rate of precipitation in spring is the fastest,and there is no obvious sudden change year?There are 7 great changes in the precipitation of Turpan and 6 great changes in Hami?The annual NDVI value in East Xinjiang(May-October)shows an upward trend on the whole?The average annual NDVI value of Turpan and Hami is 0.056 and0.059? The monthly NDVI value in eastern Xinjiang shows a trend of rising first and then decreasing ? NDVI value begins to rise continuously in May,reaches its maximum in July,then declines gradually,and reaches its minimum in October?The main vegetation types in eastern Xinjiang are medium and low coverage vegetation,accounting for more than 60% of the total vegetation area?The annual NDVI value in Turpan City is positively correlated with the average annual temperature,with a correlation coefficient of 0.019?The annual NDVI value in Hami City is negatively correlated with the average annual temperature and the correlation coefficient is-0.102?At the level of 0.05,the annual NDVI value in Turpan City is positively correlated with precipitation,with a correlation coefficient of 0.504?The annual NDVI value in Hami City is significantly related to water drop and the correlation coefficient is 0.709?The vegetation NDVI in eastern Xinjiang can delay the response of temperature and precipitation?The correlation between NDVI value in July and average temperature in August is the best ? There is a positive correlation between precipitation and NDVI value in Turpan,and the correlation between precipitation in June and NDVI value in July is better?There is a remarkably positive correlation between NDVI value and water drop in June of Hami city.