Responses Of Recent And Future Vegetation To Climate Change In The Inner Mongolia

Incorporating various information such as GIMMS NDVI 3g data, observation data including temperature, precipitation etc., this paper conducts a research about the responses of recent vegetation to climate change in the Inner Mongolia region. In order to study the effects of future climate change on vegetation in the Inner Mongolia region,this paper uses three atmosphere forcing data sets to drive the pattern of land surface process(CLM4-CN-DV) so as to gain the simulation results in 2081-2100 of three climate patterns under RCP8.5 scenario to study the responses of vegetation to climate change in the Inner Mongolia.Consequently, the principal conclusions are raised as follows:(1) With the impact of global warming, there emerged a significant rise in the temperature of Inner Mongolia from 1982 to 2012, and precipitation, however, has demonstrated a trend of fluctuating reduction; climate change has displayed an apparent warming and drying tendency overall. The vegetation in growing season in the region of Inner Mongolia was seen with a fluctuation variation trend; which at the end of the 20th century started to decrease distinctly, yet with significant spatial differences.(2) From the perspective of inter-annual variability, vegetation is greatly affected by precipitation; the response of NDVI in the growing season of vegetation to climate change manifests that the temperature plays a slightly larger role in driving the vegetation ecosystem compared to the precipitation, and also the way of response regarding vegetation in different regions varies. As far as the vegetation type is concerned, the forest to temperature or precipitation responses with barely retardation time; Grassland and farmland, however, response to the temperature and precipitation with a lag time of a month.(3) In 1982-2012, CLM4 land model driven by three atmosphere forcing data sets can represent the contemporary climate and vegetation distribution in the Inner Mongolia. The ability of model simulation to temperature is good, and GFDL-CM3 has the best ability of simulating the temperature trend. While MIROC-ESM can accurately simulate the temperature value, CCSM simulated temperature is higer than observation, but GFDL-CM3 simulation is lower than observation. In terms of the spatial distribution of temperature, CCSM performs good at simulating western Inner Mongolia, GFDL-CM3 simulates good at eastern Inner Mongolia. Besides, the model simulation of annual precipitation is not very good, the ability of simulating precipitation trends is so so. GFDL-CM3 can accurately simulate the annual variance of precipitation, howerver, MIROC-ESM simulated precipitation lead about a month before observation. In terms of the spatial distribution of precipitation, CCSM performs good at simulating. Patterns also have a certain ability of simulating vegetation, GFDL-CM3 and MIROC-ESM can correctly simulate the vegetation change. And the simulation of vegetation is two month later than observation. Besides, the three modes can basically simulate the spatial distribution of vegetation.(4) The temperature and precipitation in the Inner Mongolia show different levels of increasing trend in the future under RCP8.5 scenario, among which, the simulated temperature (0.1℃/a) under GFDL-CM3 pattern and the simulated increased rainfall (4.2mm/a) is the most obvious. In terms of season, autumn has an obvious increase in temperature, with a significant precipitation change. Moreover, the spatial changes of simulated temperature in different patterns are basically the same, but there is an obvious spatial difference in the forecast of precipitation trend. There emerges a significant rise in the LAI of the three patterns, among which, the simulated LAI (0.014/a) under CCSM pattern is the most obvious. With the impact of global warming, the correlation between LAI and temperature is greater than precipitation.