Ecoclimate Teleconnections: Effects of a Shifting Intertropical Convergence Zone (ITCZ)

该项目的目标是量化生态系统-气候或生态气候遥相关对原始强迫偏远地区的影响，并确定与这些地区生态系统结构、功能和生产力变化相关的反馈。先前的工作表明，中纬度森林覆盖率的增加可以提高北半球的温度，并有能力改变热带的一般环流和与热带辐合带(ITCZ)有关的降水位置。这种由生态系统驱动的远程联系通过大气循环将遥远陆地地区的生产力联系在一起。通过全球尺度环流模型和生态系统动力学模型的离线耦合方法，将量化与植被覆盖变化相关的反馈的一阶影响。特别是，将量化中纬度树木复盖对ITCZ位置的影响，并评估由此产生的热带森林生产力和结构的变化。还将研究热带森林结构的任何变化对全球气候系统的影响。该项目将解决的科学问题如下：中纬度树木覆盖的大范围变化是否会通过大气遥相关破坏世界其他地区的生态系统的稳定？这些生态气候遥距联系是如何通过大气传递的？中纬度树木覆盖率需要有多大的变化才能影响热带森林？提高对生态系统-气候相互作用的理解具有重大而广泛的影响。

The goals of this project are to quantify the impact of ecosystem-climate, or ecoclimate, teleconnections on regions remote to the original forcing and to identify feedbacks associated with the change in ecosystem structure, function, and productivity in those locations. Prior work has shown that an increase in mid latitude forest cover can raise northern hemisphere temperature and has the ability to shift the general circulation of the tropics and the location of precipitation associated with the intertropical convergence zone (ITCZ). This ecosystem-driven teleconnection links productivity in land regions remote to one another through the circulation of the atmosphere. Through an offline-coupling approach with both a global-scale circulation model and a model of ecosystem dynamics, the first order impact of feedbacks associated with changes in vegetation cover will be quantified. In particular the impact of mid latitude tree cover on the location of the ITCZ will be quantified and the resulting change in tropical forest productivity and structure will be assessed. The impact of any changes in tropical forest structure back onto the global climate system will also be examined. The scientific questions that will be addressed in this project are the following: Can large-scale changes in mid latitude tree cover destabilize ecosystems in other parts of the world through atmospheric teleconnections? How are these ecoclimate teleconnections communicated through the atmosphere? How much change in mid latitude tree cover is needed to impact forests in the tropics? Improved understanding of ecosystem-climate interactions has substantial broader impacts.