Study On The Correlation Between Vegetation EVI And Climatic Factors In China Based On Data Reconstruction

In response to the adverse changes in the global climate,it is a very threatening challenge to ecological civilization,therefore,it is of great significance for timely and effective prediction of the impact of rapid climate change on vegetation growth to the prevention and control of global disastrous events.In the paper,what the data used include China's surface daily temperature and daily precipitation data from 2000 to 2019,the enhanced vegetation index EVI(Enhanced vegetation Index)time series data in MODIS,and the China's topographic elevation DEM(Digital elevation Model)data.First of all,after 20 years of pretreatment of temperature and precipitation in China,the thin plate spline function interpolation and the linear trend analysis are used,and temporal and spatial variation characteristics of temperature and precipitation in China are obtained.In China,the average annual temperature from2000 to 2019 showed an upward trend,with a maximum temperature difference of1.11 ?;the spatial variation of temperature is gradually decreasing from north to south and from west to east.The average annual precipitation in China shows a slight upward trend from 2000 to 2019,with a maximum change of 159.1mm;and the spatial variation characteristics of precipitation are decreasing from southeast to northwest.Besides,the graph theory neighbor interpolation method is put forward.It makes noise removal for the index EVI of vegetation in China from 2000 to 2019 to figure out the annual and monthly average EVI data distribution.In addition,the linear trend method is used to analyze so that the temporal and spatial variation characteristics of vegetation index EVI in china are obtained.EVI has maintained an upward trend for20 years.The Vegetation rate of vegetation cover in the northern region is the largest,and the growth rate of the Qinghai-Tibet region is the smallest and almost unchanged;The areas with obvious reduction of EVI are mainly concentrated in the Yangtze River Delta urban agglomeration,the Pearl River Delta urban agglomeration,the major coastal urban areas and the four major basins in the northwest region.The largest spatial distribution of Chinese EVI is the middle and high vegetation distribution area(EVI is more than 0.6),accounting for 55.32% of the whole country.In the end,the relationship between EVI and temperature,EVI and precipitation is studied,respectively.The Pearson Correlation Analysis is used to obtain the correlation coefficient between EVI and temperature r=0.61 and the correlation coefficient between EVI and precipitation r=0.49,which shows that temperature and precipitation have a certain impact on EVI.After that,by using partial correlation analysis among them,the significant partial correlation region between EVI and temperature accounts for 32.77% of the total area,the non-significant partial correlation region is concentrated in the margin,plain and plateau areas of the major mountains;a significant partial correlation between EVI and precipitation accounts for 43.97% of the total area,which is mainly concentrated in plateau area,plain area,basin,mountain area and island area.