The Impact Of Climate Change On The Growth And Distribution Grassland In Inner Mongolia

We used the meteorological data of 1962-2011 and NDVI data of 1982-2011 years in Inner Mongolia steppe to the、the time change trends and magnitude dynamic of the temperature and precipitation in annual, growing season, and non-growing season, and analysis spatial distribution and temporal dynamics on NDVI index of the spring, summer, autumn and winter four seasons with different types grassland, and made the relevant of test to the temperature、precipitation and the annual maximum of NDVI in each area separately, get the climate and vegetation change characteristics and response of vegetation to climate change of Inner Mongolia about nearly five decades, the main conclusions are as follows:(1)The temperature distribution patterns in Inner Mongolia steppe was from east to west, the overall gradient was from low to high, but distribution in the typical steppe was from high to low. The overall variation characteristics during 50a the temperature annual fluctuated with upward trend, average warming rate of 0.49℃/ 10a. The change trend of temperature of different grassland types was significantly increased, the change trend of forest steppe、typical steppe and desert steppe is similar to the region’s, the growth rate of typical steppe was slightly lower than other regions, average warming rate of 0.37℃/ 10a; the growth rate of forest steppe was lower than other regions in no-growing season, average warming rate of 0.49 ℃/ 10a. The temperature of different steppe mutated in about 1990 of annual time series, and delayed until around 1995 in the growing season time series.(2) Inner Mongolia grassland area have a strong zonal in precipitation patterns, from east to west in the direction of the forest steppe, typical steppe, desert steppe and desert steppe gradient from high to low distribution. The region’s rainfall was generally volatile trends in 1962-2011, annual maximum rainfall had reached 495mm in 1998, while the minimum rainfall of 219mm in 2001.Overall, changes in precipitation are volatile in the forest-steppe zone and typical steppe zones among fifty years, Inter annual rainfall has a large variation margin, while the precipitation in desert steppe and steppe desert region are more stable, precipitation in every steppe have no significant increase or decrease trend. Forest steppe zone had precipitation increase and decrease mutation in 1997 and 2002, and the typical steppe region had precipitation increase and decrease mutation in 1992 and 2006.Inner Mongolia steppe precipitation mainly in the growing season, so the distribution pattern and time series presented consistent with the annual trend and the precipitation is slightly less than the full year. Forest steppe has occur during the growing season precipitation increases mutation year ahead to 1992.Due to the non-growing season precipitation rarely, it changes the amplitude fluctuations is small, but the spatial pattern of distribution is consistent with the trends and year-round.(3) In past 30a, the change trend of NDVI of Inner Mongolia steppe region in the season were more stable, but differ in different types of grassland, Each type of grassland NDVI change from east to West differentiation differ greatly, forest steppe and typical steppe varies with the season with greater volatility, desert steppe and steppe desert three decades of time series trend is almost unchanged. In different seasons, the fluctuation of NDVI of Inner Mongolia grassland area is mainly concentrated in summer and autumn, in spring, forest steppe and typical steppe region of NDVI showed a weak increasing trend, desert steppe and steppe desert has no obvious change; In summer, the trend of various types of grassland areas are not obvious, but the forest steppe zone and typical steppe region has a large volatility; The trend of NDVI variation is still a continuation of the summer condition, the mean forest steppe and typical steppe is slightly lower than the mean summer, desert steppe and steppe desert and the same summer; In winter, the forest steppe NDVI changes the most volatile, while no obvious change. Typical of the grassland NDVI showed a slight increasing trend. Desert and desert steppe NDVI grassland remain stable trend.(4) Relevance of climate change and NDVI. During the growing season in the forest steppe, typical steppe and desert steppe of average temperature and NDVI showed significant negative correlation, desert grassland growing season average temperature has no obvious relation with NDVI; precipitation was positively correlated with NDVI in forest and grassland in growing season. Growing season precipitation and NDVI was a significant positive correlation in typical steppe and desert steppe. Growing season precipitation and NDVI was no significant correlation and the test did not pass in desert grassland.