Understanding Intraseasonal Convection and Large-Scale Circulation Variations in Observations and Climate Models

该项目旨在提高我们对热带对流和大尺度环流之间相互作用的理解，特别关注马登-朱利安振荡（MJO）。MJO对流可能与大尺度环流联系在一起的三种机制有待研究：地面风辐合、对流层湿度变化和地面蒸发变化。观测工作包括对流层湿度变化在影响季节内对流中所起的作用，地面蒸发变化在确定亚季节对流的特征和位置中的重要性，季节内对流对大尺度气流施加的地面风辐合的依赖性，以及确定热带天气尺度扰动，热带气旋变率，和亚季节风的变化。模式性能与观测结果的比较将有助于改进对流参数化。这些活动将与国家大气研究中心的大气模型工作组协调，该工作组负责社区气候系统模型2.0版大气部分的开发。它将增加知识的身体特别是马登-朱利安振荡，并了解对流和大尺度环流的相互作用一般。研究结果将通过会议和在国际公认的科学期刊上发表的出版物传播。

This project is designed to improve our understanding of the interactions between tropical convection and the large-scale circulation, focusing particularly on the Madden-Julian Oscillation (MJO). Three mechanisms by which MJO convection may be linked to the large-scale circulation are to be studied: surface wind convergence, tropospheric moisture variations, and surface evaporation variations. Observational work includes the role played by tropospheric moisture variations in influencing intraseasonal convection, the importance of variations in surface evaporation in determining the character and location of sub-seasonal convection, the dependence of intraseasonal convection on surface wind convergence imposed by the large-scale flow, and the mechanisms which determine the strong relationship among tropical synoptic-scale disturbances, tropical cyclone variability, and sub-seasonal wind variations. A comparison of model performance to observations will enable progress toward an improved convective parameterization. These activities are to be coordinated with the Atmospheric Model Working Group at National Center for Atmospheric Research which is responsible for developments in the atmospheric component of the Community Climate System Model, version 2.0.Broader impactsThis research will support one student. It will add to the body of knowledge of the Madden-Julian Oscillation in particular, and to the understanding of the interactions of convection and large-scale circulation in general. The results will be disseminated via meetings and publications in internationally-recognized scientific journals.