Time lag analysis between vegetation and climate change in Inner Mongolia

Relationship between vegetation and climate has been a hot spot in climate change researches since vegetation is a key component of land ecosystem that represents climate change. In this study, GIMMS NDVI data and meteorology data (precipitation and temperature) from 1982 to 2006 are used to do time lag analysis between NDVI and precipitation/temperature. First, whole time series NDVI and precipitation/temperature time lag analysis were done in two spatial scale- pixel and vegetation type districts. While in pixel scale, results show that NDVI has at least one month time lag with precipitation and temperature when they have significantly correlation. Different vegetation types response distinctly with climate conditions and Northern Temperate Meadow Steppe and Southern Cool Temperate Deciduous Needle-leaf Forest change immediately with climate, where maximum correlation coefficients appears between NDVI and climate factors at the same month. Comparatively, there are time lags in other regions. Second, we studied inter-annual time lag effects in growing season (from April to September) and accumulation effects of precipitation and temperature.