Spatial-temporal changes of climate and vegetation cover in the semi-arid and arid regions of China during 1982—2006

The spatial-temporal changes of climate(temperature and precipitation) and vegetation cover in the semi-arid and arid regions of China during 1982—2006 were analyzed based on global temperature and precipitation data from Climatic Research Unit(CRU) and the Normalized Difference Vegetation Index(NDVI) from NOAA/NASA.The results show that the climate trends to be warm-wet in general,although the precipitation decreases in some areas of the inland semi-arid and arid regions of China,which are consistent with the previous studies.Under the warm-wet climatic background,the vegetation cover increases in most areas(1%.(10a)-1),especially in the northwestern Xinjiang Autonomous Region and the southeastern Qinghai province.However,the vegetation cover decreases slightly in the partial areas [(0~-1)%.(10a)-1] such as the southern and eastern Xinjiang Autonomous Region and the northwestern Gansu province.In addition,it is found that the increases in both precipitation and temperature,which sequentially prolongs the growing season,significantly improve the vegetation cover of Urumqi city during the past 25 years.