亚热带森林碳循环对极端高温干旱的多尺度时空响应机制

Subtropical forests play an important role in the global carbon cycle. Extreme heatwave and drought have great impact on the carbon cycle of subtropical forests, but their spatiotemporal mechanism is still unclear. This study will take China's subtropical forest ecosystem as the research object, obtain multi-spatial scale data through sample survey, remote sensing, and hierarchical Bayesian techniques, and use sensitivity analysis combined with particle filter method to optimize key ecophysiological parameters, then drive BIOME-BGC to simulate and analyze the multi-scale spatiotemporal evolution trend of subtropical forest carbon cycle; based on historical and future climate scenario data, the heat wave index and standardized precipitation evapotranspiration index are used to reconstruct the spatiotemporal pattern of subtropical extreme heatwave and drought events in China, and the frequency, duration and intensity of different spatial and temporal scales are analyzed; Finally, using the carbon flux normalization anomaly index and its correlation coefficient with the two indices, to analyze the direct and indirect effects of extreme heatwave and drought on the carbon cycle of subtropical forests, and constructing the structural equation model to reveal the multi-scale response mechanism of subtropical forest carbon cycle to extreme high temperature and drought. The results will provide important scientific evidences for correctly evaluating subtropical forest responses and adapting to global climate change, and provide theoretical references for subtropical forest management and formulate measures of mitigation and adaptation to climate change.

亚热带森林在全球碳循环中具有重要地位，极端高温干旱对亚热带森林碳循环造成了巨大影响，但其时空影响机制仍然不清。本研究将以我国亚热带森林生态系统为研究对象，通过样地调查、遥感、层次贝叶斯等技术获取多空间尺度数据，利用敏感性分析结合粒子滤波方法优化关键生理生态参数，驱动BIOME-BGC模型模拟并分析亚热带森林碳循环多尺度时空演化趋势；基于历史及未来气候情景数据，采用热浪指数和标准化降水蒸散指数重建我国亚热带极端高温干旱事件时空格局，分析不同时空尺度的频率、持续时间和强度演变特征；最后，利用碳通量标准化异常指数及其与两种指数的相关系数，分析极端高温干旱对亚热带森林碳循环的直接和间接影响，构建结构方程模型，揭示亚热带森林碳循环对极端高温干旱的多尺度响应机制。研究结果将为正确评价亚热带森林响应和适应全球气候变化提供重要科学依据，为亚热带森林经营管理及制定减缓与适应气候变化的措施提供理论参考。

亚热带森林在全球碳循环中具有重要地位，极端高温干旱对亚热带森林碳循环造成了巨大影响，但其时空影响机制仍然不清。本研究以我国亚热带森林生态系统为研究对象，通过样地调查、遥感、层次贝叶斯等技术获取多空间尺度数据，优化关键生理生态参数，驱动BIOME-BGC等生态系统过程模型模拟并分析亚热带森林碳循环多尺度时空演化趋势；基于气候情景数据，采用热浪指数和标准化降水蒸散指数重建我国亚热带极端高温干旱事件时空格局，分析不同时空尺度的频率、持续时间和强度演变特征；最后，利用碳通量标准化异常指数、地理空间分析、偏相关系数等方法，分析极端高温干旱对亚热带森林碳循环的直接和间接影响，揭示亚热带森林碳循环对极端高温干旱的多尺度响应机制。研究结果将为正确评价亚热带森林响应和适应全球气候变化提供重要科学依据，为亚热带森林经营管理及制定减缓与适应气候变化的措施提供理论参考。