亚热带北缘常绿阔叶成熟林碳储量对台风响应的模拟研究

Typhoon is prevailing in the north subtropical mature forest area of coastal area in China, and the impact of typhoon on forest ecosystem carbon (C) stocks is still unclear. The field survey and continuous measurements would be conducted in a subtropical evergreen broad-leaf forest station (Tiantong, Zhejiang) to capture the response of litter fall seasonal dynamics and trees mortality to typhoon disturbance. An ensemble Kalman filter (EnKF) method was used to optimize process-based model specific modules and sensitive parameters against the surveyed C pool components data and litter fall measurements. Coupled with CI-LUE GPP products, optimized litter fall module and soil carbon module of three process-based models (TECO，CABLE，CoLM) were used to simulate the Tiantong subtropical evergreen broad-leaf forest ecosystem C storage variability(2011-2019), respectively. And evaluated the applicability of optimized specific module from the process-based model ensembles to typhoon disturbance. Spatial-temporal patterns (2011-2019) of C stock in north subtropical costal area of evergreen mature forest widely-distributed were then simulated by the ensemble of process-based models coupled with CI-LUE, and analyzed the uncertainties in the effect of typhoon on C stock of costal north subtropical mature forested area.

我国沿海北亚热带成熟林集中分布区台风频发，对森林生态系统碳储量的影响仍然充满不确定性。本研究将以浙江天童亚热带常绿阔叶林为研究对象，通过连续野外观测描述亚热带常绿阔叶林凋落物季节变异及树木死亡对台风干扰的响应。利用集合卡尔曼滤波同化方法结合碳库组分和凋落物观测数据优化生态系统过程模型中的关键模块，校正关键参数和评价优化结果。基于光能利用率模型（CI-LUE）的GPP产品，耦合优化后的三个生态系统过程模型（TECO，CABLE，CoLM）的凋落物模块与土壤碳库模块来模拟天童山常绿阔叶林2011-2019 年的生态系统碳储量变异，评价三个优化的过程模型关键模块对模拟台风干扰的适用性。基于参数优化和耦合的生态系统过程模型，集成模拟我国沿海北亚热带常绿成熟林集中分布区2011-2019的碳储量时空格局，分析日益加剧的台风对沿海北亚热带常绿林地区碳储量格局影响的不确定性。

我国南方的亚热带森林作为一个重要碳汇，近年来频繁受到台风干扰的影响。项目将以浙江天童亚热带常绿阔叶林为研究对象，通过分析碳库组分观测数据与环境因子之间的关系，发现凋落物量主要受到极端温度，降水和风速的影响。植被遥感数据监测表明，常绿阔叶林的植被生产力对极端事件具有较高的抵抗力。基于构建的模型，在站点尺度模拟了天童常绿阔叶林生态系统储碳能力对于台风干扰的响应，结果发现当台风干扰指数较低时，生态系统的储碳能力主要是由植被生物量的碳滞留时间决定的。在台风频发背景下，项目成果为实现区域尺度准确模拟生态系统储碳能力对台风干扰的响应提供了理论支持。