Evaluation of Vegetation Responses to Climatic Factors and Global Vegetation Trends using GLASS LAI from 1982 to 2010

Vegetation growth has been profoundly affected by global climate change. It is important to investigate vegetation responses to climatic factors and vegetation trends with remote sensing data. In this study, we explored the responses of global vegetation to 3 climatic factors (temperature, precipitation, and solar radiation) and global vegetation trends based on the Global Land Surface Satellite (GLASS) Leaf Area Index (LAI) dataset from 1982 to 2010. The main findings are: (i) the vegetation responses to temperature and precipitation have no apparent time-lag and the vegetation response to the solar radiation has a time-lag of 1 month in most places in the northern hemisphere; (ii) the driving factor of the growth of vegetation was air temperature, followed by precipitation and solar radiation; (iii) the closest relationships between vegetation and climatic factors were observed in mixed forest, deciduous needleleaf forest, and shrublands at northern mid- and high-latitude; (iv) a map of global vegetation trends from 1982 to 2010 was derived, and showed that the proportion of vegetated pixels with significant increasing and decreasing trends was 34.73% and 6.59% (p<0.05), respectively; (v) more reasonable vegetation trends can be obtained from the GLASS LAI dataset in the perennial cloud-covered regions.