Validation of the Integrated Biosphere Simulator in simulating the potential natural vegetation map of China.

The Integrated Biosphere Simulator (IBIS)-a Dynamic Global Vegetation Model-was validated by simulating the potential natural vegetation map of China using data on monthly mean climate from 1961 to 1990, soil texture, and topography. Although the vegetation map simulated by IBIS was able to describe the sketch of vegetation patterns in China, the distributions of several plant functional types (PFTs) and vegetation types were still simulated incorrectly, especially in eastern temperate areas, southern subtropics, the southern Sichuan basin, and the Hengduan mountains area. By adjusting some of the climatic constraints and physiological parameters of PFTs defined in IBIS, the simulated distributions of PFTs became reasonable, and the simulated vegetation map fitted the natural vegetation map better. The kappa statistic between the simulated and the natural vegetation maps was 0.76, an increase of 16.9% from the previous parameter adjustment of 0.65. Correspondingly, the degree of agreement between these two maps rose from 'good' to 'very good'. After the parameter adjustments, IBIS became more suitable for the large-scale simulation of Chinese natural vegetation distributions and could provide a powerful support to reveal the dynamic responses of terrestrial ecosystems to climate change in China. [ABSTRACT FROM AUTHOR]