Dynamics Of Vegetation And Phenology And Their Response To Climate Change Based On Multisource Data In The Arid And Semiarid Region,China

In this paper, based on GIMMS and MODIS data sets of multi-temporal and spatial resolution,regional climate data and ground-based observations, we analyzed the distribution characteristic and varation of NDVI and phenology in the whole study region, different climate zone, different vegetation and landuse types from 1982 to 2013, and also dicussed the correlations between NDVI-. phenology and surface temperature、precipitation. To explore the relationship between spatial-temporal variations of vegetation and climate change will contribute to fully understand impact of climate change on vegetation dynamics of arid and semiarid region.This knowledge not only provide sicientific support to develop a reasonable strategy of vegetation restoration, but make an important guiding role to enhance adaptation and mitigation abilities. The main conclusions are as follows:The spatial distribution of climate factors is difference.In the past 54 years, temperature and precipitation increased, relative humidity、wind speed and sunshine hours decreased. The spatial distribution of NDVI mainly increased in the arid and semiarid region during 1982-2013 and the eastern part is high, the western part is low. In all, the temperal and spatial of vegetation varied extentivly in arid and semi-arid areas of China and vegetation had been improved, that is NDVI in the most of regional showed a increasing trend. Due to the double effects of human activities and climate change, vegetation showed a decreasing trend in some regions. As a result of difference in vegetation type, landuse and climate, vegetation showed different changes in different regions. For the totally region, the trend of NDVI increased significantly at a rate of 0.04/100a, the upward trend is the same from spring to autumn,and the downward in winter. In general, NDVI had positive relations with temperature and precipitation in most regions with the percent of 60.79% and 71.29% of total pixels and difference existed in different climate zones, vegetable types and landuse types.Regional vegetation phenology showed obvious spatial variations. On the whole, the trend of SOS was not obvious, and most was in advance. The trend of EOS was delayed in some regions and was in advance in some other regions. The trend of LOS was delayed in most regions. The vegetation phonological parameters varied with the vegetation, landuse and climate zones.The relations between vegetation phonological parameters and the temperature and precipation differed in different regions. In all, temperature and precitpation made positive effects on the phenology in arid and semi-arid regions, and the influence of temperature and precipitation on phonological parameters had a certain time lag.