THE NET PRIMARY PRODUCTION SIMULATION OF TERRESTRIAL ECOSYSTEMS IN CHINA BY AVIM

In this paper we used an Atmosphere-Vegetation Interaction Model (AVIM) that has been validated at regional and global scales to estimate the NPP (net primary production) variation of modern Chinese terrestrial ecosystems and its responses to the climate change. AVIM consists of two inter-coupled components: physical process and eco-physiological process, involving the mater and energy balance between the atmosphere, vegetation and soil. Chinese vegetation is classified 9 types and soil texture is classified into 6 types. The parameters of eco-physiological processes for each vegetation type for AVIM are collected. Daily weather data for 0.5×0.5 grid cells as the forcing of the model are generated from the monthly climate data, coming from the climate research unit, University of East Anglia, UK. The estimated NPP of chinese vegetation changes from 0 to 1 389 gC/(cm~2·a), averaging 355 gC/(cm~2·a). Vegetation from the rain forest has the high NPP value, and the low NPP corresponding to the shrub with no cover. The NPP decreases from east to west in China, with the highest NPP occuring at the south area of Yunnan Province, and the lowest appearing at Tibet and Xinjiang areas. Total NPP of the terrestrial ecosystems is (3.33) Pg C, suggesting that such amount of carbon is absorbed from the atmosphere by the vegetation in China. Our work also shows that precipitation is the main factor affecting the NPP of terrestrial ecosystems in China.