The Research Of Regional Difference In The Onset Of Greenness Of Vegetation And The Cause Of Climatic

Global warming has obvious effects on the terrestrial ecosystem,and vegetation phenology as an important parameter of the earth and atmospheric science research to plant's life cycle and its relationship with climate,which is the important indicator of the responsing of earth's biosphere to climate change and the easy observation,the change reflects the terrestrial ecosystem to global climate and the response of the seasonal and inter-annual variability of hydrological system.The beginning of study with the onset of Greenness is very important to understanding the interaction of global climate change and interaction by terrestrial ecosystems.This study is based on the principle of vegetation growth cycle,using of Logistic model is commonly used in plant and animal research by means of remote sensing simulation monitoring the onset of Greenness of vegetation.This study build the Logistic model based on NDVI cumulative frequency curve to have calculated the onset of Greeness by 1983-2012 in our country.It has picked up the ddifferent vegetation types' data after validation with the data of ground phenology sites.Analysis of the interannual variability of in different area in different latitude and longitude,different altitude variation characteristics,and discussed the different vegetation types of the onset of Greenness.The correlation between meteorological factors and,futher analysis of the characteristics of interannual climate.This research's main conclusions are as follows:(1)The onset of Greenness in regional scale stages in our country in the 30 years,generally ahead of trends,including parts of the qinghai-tibet plateau,Inner Mongolia plateau and vegetation green degrees of central and eastern regions in our country the onset of Greenness of interannual trend is more obvious in advance,and in the sichuan basin,Inner Mongolia in the Midwest and northeast parts of the vegetation green degree the beginning years of delays.(2)The onset of Greenness of different types of beginning period in different latitude and longitude and altitude on the interannual variability of exist certain differences.The onset of Greenness of deciduous forest types in the qinghai-tibet plateau region,as the change of the increasing of latitude and longitude,the years ahead appeared different degree of increase rate,and changes in the northeastern region is relatively moderate;The grassland types are mainly distributed in the qinghai-tibet plateau area in China and Inner Mongolia region,in the Tibetan plateau,the change of rate of the onset Greenness with the increase of latitude and longitude showed a trend of decrease the increase,then in the Inner Mongolia region,has emerged after the first delay phenomenon in advance;The onset of Greenness by farmland type of inter-annual variation in the north of our country presents the tendency of decrease gradually along with the change of latitude and longitude,and in the northeast region also appeared the phenomenon of delay.With the change of regional differences and vegetation species,change characteristics of the onset of Greenness of vegetation shows different trends.(3)Through the onset of Greenness and the correlation between meteorological factors,the correlation between meteorological factors and analysis found that the average temperature and the accumulated temperature by the onset of Greenness are significant correlation,the beginning and with the increase of temperature,vegetation green degree of beginning period showed a trend of different degrees of in advance.The onset of Greenness by different vegetation types in different latitude and longitude of the inter-annual variability of the response is differently in different meteorological factors,mainly with the accumulated temperature and average temperature in the early spring months,and in the qinghai-tibet plateau region,in winter precipitation and the onset of Greenness is one of the reasons in advance.Inner Mongolia region and northeast region in China,the onset of Greenness appeared the phenomenon of delay,it has certain positive correlation by the onset of Greenness and the precipitation and relative humidity in the beginning of spring.It has shown that the period of the precipitation and relative humidity on the green vegetation period has certain inhibition effect.