The Relationship Between Vegetation And Climate In The Indo-China Peninsula And Its Future Projections

Based on the reanalysis data of NCEP / NCAR,normalized vegetation index(NDVI),leaf area index(LAI),ENSO index,precipitation,air temperature,radiation,sea surface temperature and CMIP5 model results,this paper analyzes and discusses the vegetation change and its response to climate change in Indochina Peninsula from 1982 to 2015.We focus on analyzing its contemporaneous and non contemporaneous correlation with ENSO to provide reference for vegetation change and future prediction in this area.Based on the analysis of vegetation growth status from 1982 to 2015 and its correlation with El Ni(?)o Southern Oscillation,the results show that:(1)The high value areas of vegetation coverage are mainly located in northern Thailand and northern Myanmar.The corresponding vegetation types are evergreen broad-leaved forest,coniferous forest and mixed forest.Vegetation activity is more frequent in the area with high vegetation density.The interannual variation of vegetation in the Indochina Peninsula is significant,which is related to the tropical large-scale circulation and sea surface temperature.The high value area of the index is mainly located in the areas of broad-leaved forest and coniferous forest with dense vegetation.According to the characteristics of interdecadal change of vegetation,there is a downward trend,which may due to the continuous growth of population and the increase of human activities for a long time.(2)Based on NDVI and other meteorological data,the characteristics of vegetation cover change in Indochina Peninsula and its relationship with ENSO were discussed.The results show that precipitation is the main factor affecting the growth of vegetation in spring,and has a significant positive correlation with NDVI,while temperature and radiation have a negative correlation with NDVI.Further analysis shows that when sea surface temperature in the equatorial central and eastern Pacific in the preceding winter is warmer(El Ni(?)o event occurs),the sea level pressure is higher and the 850 h Pa wind field is divergent near the Indochina Peninsula,where the upward movement is weaker,which is not conducive to the formation of cloudiness and precipitation,but conducive to the increase of solar radiation and temperature.The reduced precipitation and higher temperature both inhibit the growth of vegetation in the Indochina Peninsula in spring.On the contrary,La Ni(?)a event in the preceding winter is favorable for the vegetation growth in the Indochina Peninsula.(3)Based on the results of CMIP5 model,the temporal and spatial variation characteristics of Indochina Peninsula in different climate scenarios in the early and middle 21st century were analyzed.BNU-ESM and IPSL-CM5A-LR models with obvious trend differences were selected for typical analysis,and the effects of temperature,precipitation,radiation and sea surface temperature differences of the two models on vegetation growth were compared.The results show that the increase of precipitation is beneficial to vegetation growth,while the increase of temperature is beneficial to vegetation growth in high latitude(high temperature)areas,while it is opposite in low latitude areas On the contrary.The enhancement of solar radiation is not conducive to the growth of vegetation.The change trend of SST and vegetation is in the same direction,that is,the vegetation increases with the rise of SST.