Impact of precipitation on vegetation biomass in northern China

Water is one of the primary factors limiting terrestrial biological activity, particularly in arid and semi-arid regions. This study focuses on the temporal and spatial variation between vegetation green biomass and precipitation parameters, namely annual precipitation (AP), annual effective precipitation (AEP), annual precipitation uniformity (APU) and growing season precipitation (GSP), in northern China. The relationship between vegetation and precipitation was investigated using Normalized Difference Vegetation Index (NDVI) images (1982-2006) derived from the GIMMS dataset, and precipitation data from 297 weather stations throughout northern China. Results indicate vegetation green biomass increase linearly (P<;0.001) across both AP and AEP gradient, but increase nonlinearly through APU gradient. There are 82, 78 and 33 stations of 297 with positive linear relationship (P<;0.05) between NDVI and AEP, AP and GSP respectively and 50 stations with negative linear relationship (P<;0.05) between NDVI and APU. Moreover, most stations with NDVI significantly linearly related to precipitation parameters distribute within the 200-400mm annual precipitation isoline. The results confirm the lag and accumulation effect of precipitation on vegetation and also help understand the tendency and spatial pattern of vegetation response on climate change in the future.