Analyses of Large-Scale Climate Variability

该项目将利用数值试验和观测分析来研究气候动力学领域中两个尚未解决的问题：1）是什么物理机制驱动对流层对对流层外平流层变率的反应？2）人类排放的二氧化碳和消耗臭氧层的气体通过什么过程驱动了大气层外环流的大规模变化？在建模部分，研究人员将检查和诊断简单的大气环流模型对空间变化热力强迫的反应，这些热力强迫模拟了对大气二氧化碳增加和平流层臭氧消耗/恢复的辐射反应。这些实验将用于：（1）评估对流层和平流层对热力强迫的环流反应;（2）评估对强迫的形状和幅度变化以及对模式气候学变化的反应的稳健性;（3）调查驱动模拟反应的物理机制。在观测部分，研究人员将进行分析，1）补充数值实验，2）调查与最近平流层气候变化相关的过程。观测分析将为模式实验提供“现实检查”，对与平流层/对流层耦合有关的热量和动量通量的每日演变进行新的分析，并对热带对流层加热与对流层外气流变率之间的联系进行新的分析。（通过平流层/对流层耦合）、过去气候趋势的归因以及对响应于人为强迫的环流未来变化的预测。该项目将培养和支持一名博士后研究员和两名研究生。

The project will use both numerical experiments and observational analyses to investigate two unsolved questions in the field of climate dynamics: 1) what physical mechanisms drive the tropospheric response to extratropical stratospheric variability? and 2) through what processes do anthropogenic emissions of carbon dioxide and ozone depleting gases drive large-scale changes in the extratropical circulation? In the modeling component, the investigators will examine and diagnose the simple general circulation model response to spatially varying thermal forcings which mimic the radiative responses to increasing atmospheric carbon dioxide and stratospheric ozone depletion/recovery. The experiments will be used to 1) assess the circulation responses to thermal forcings at tropospheric and stratospheric levels; 2) assess the robustness of the responses to changes in the shape and amplitude of the forcings and to changes in the model climatology; and 3) investigate the physical mechanisms that drive the simulated responses. In the observational component, the investigators will conduct analyses that 1) complement the numerical experiments, and 2) investigate the processes associated with recent stratospheric climate change. The observational analyses will provide a "reality-check" for the model experiments, new analyses of the daily evolution of the heat and momentum fluxes associated with stratosphere/troposphere coupling, and new analyses of the linkages between tropical tropospheric heating and variability in the extratropical flow.The broader impacts of this work include implications for weather forecasting (via stratosphere/troposphere coupling), for the attribution of past climate trends, and for the prediction of future changes in the circulation in response to anthropogenic forcing. This project will train and support one postdoctoral researcher and two graduate students.