气候变化对中国植被可能影响的模拟

依据我国植被和气候的关系对生物地理模式MAPSS中的某些参数和过程进行了调整。将改进后MAPSS模拟的当前气候状况下潜在植被类型及叶面积指数的分布与我国植被区划图和多年平均的NDVI（NOAA／AVHRR）比较，发现结果有了很大的改进。将大气环流模式HadCM2对未来气候变化的预测结果应用于改进后的MAPSS对我国植被未来的变化进行了模拟。考虑到未来大气升高的CO2浓度对植物水分利用率（WUE）的可能影响，进行了WUE变化和不变化2种预测。结果发现未来气候变化可能导致我国东部森林植被带的北移，尤其是北方的落叶针叶林的面积减少很大，以至可能移出我国境内；华北地区和东北辽河流域未来可能草原化；西部的沙漠和草原可能略有退缩，相应被草原和灌丛取代；高寒草甸的分布可能略有缩小，将被萨瓦纳和常绿针叶林取代。同时模拟的结果表明模型对WUE非常敏感。最后对结果的不确定性进行了讨论。

Modelling the Vegetation of China under Changing Climate

The Mapped Atmosphere-Plant-Soil System (MAPSS) model has been improved for simulating the potential vegetation distribution over China. Unlike North America, the environment in East China is largely controlled by the monsoon system, which affects the vegetation distribution differently than in North America. Furthermore, in MAPSS, the boreal forest is evergreen conifer, whereas in China it is largely deciduous conifer. To make the MAPSS results more suitable over China, we modified the lowest monthly temperature, which determines the northward boundary of temperate deciduous forest from -16o to -28oC. In addition, the minimum monthly rainfall during the growing season, which is used to judge broad-leaved-deciduous from evergreen need-leleaved forest, was changed from 40mm to 20mm. Other parameters related to rainfall patterns were also changed. The results were greatly improved, when compared to the map of Chinese vegetation zonation and more than 12 years of satellite data (NDVI). Using output from the General Circulation Model, HadCM2, for simulating possible future climate changes induced by enriched greenhouse gases (GHG) and sulfate aerosols (SUL), we simulated the possible future (2020s, 2050s) potential vegetation distribution modeled by MAPSS with and without consideration of CO2-induced water-use-efficiency (WUE) changes. The results show that in East China, forest boundaries could shift northward, especially the boreal deciduous conifer forest, which may disappear from China. In the North China, and Liaohe river drainage area, forests and savannas could be replaced by grasslands.