动态植被模型模拟的植被季节变化及其评估

Seasonal Cycle of Terrestrial Vegetation Simulated by a Dynamic Vegetation Model and Its Assessment

利用MODIS卫星观测资料,对一个考虑了生态系统碳氮循环过程的动态植被模型ICM的模拟性能进行了评估。重点对反映植被动力学的关键参数——叶面积指数(LAI)的模拟结果与观测进行了对比分析,评估了ICM对LAI季节变化特征的模拟能力。结果表明,ICM基本能够模拟出植被的季节变化特征。总体而言,模拟值在低纬度和高纬度地区大于观测值,中纬度地区小于观测值;模拟的植被生长常落后于观测,造成了模拟偏小值的出现与植被的生长季节相对应;模拟没有表现出热带常绿阔叶林和农作物LAI季节变化的双峰结构;模式对草地的模拟总体上优于林地。结果可为进一步改进动态植被模式的参数化方案和优化模型参数提供一定参考。

Based on the MODIS observations,the performance of Interactive Canopy Model（ICM）,a dynamic vegetation model including the carbon and nitrogen cycles of the terrestrial ecosystem,has been assessed. The Leaf Area Index （LAI）,a key parameter with seasonal variation in vegetation dynamics,is simulated by ICM and compared with the MODIS data. The results show that ICM can simulate the main characteristics of the seasonal LAI fluctuations. Compared to the observation,LAI is overestimated in high and low latitudes,but underestimated in middle latitudes by the model. The underestimation of the LAI in middle latitudes is followed by the vegetation sprout for the reason that the modeled growth is always slower than the observed one. The bimodal distributions for the tropical evergreen broadleaf trees and crops have not been well captured. In addition,the simulated results for the grassland are more reasonable than other Plant Function Types （PFTs）. The results will provide important clues for the parameterization improvement and parameters optimization of the ICM.