Tropical Intraseasonal Variability in Models and Observations

模型和观测中的热带季节内变化

• 批准号: 1441916
• 负责人: Eric Maloney
• 金额: $ 49.3万
• 依托单位: Colorado State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-12-15 至 2019-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1441916&HistoricalAwards=false
• 关键词: Tropical; Intraseasonal; Variability; Models; Observations

Understanding tropical intraseasonal variability is an important problem in climate dynamics. The goal of this project is to enhance understanding of the basic dynamics of the Madden-Julian oscillation (MJO). The broader impacts of this effort are very high. In collaboration with NCAR, the PI will incorporate newly developed process-oriented diagnostics into a diagnostics package that will be applied to different versions of NCAR's Community Earth System Model (CESM) to evaluate--and eventually improve--the representation of the MJO. In addition, there will graduate student and postdoc training as well as the development of diagnostic capabilities that could be used by the climate science community to potentially improve model simulations.The leading hypothesis that will be examined in this project is that wind-evaporation and radiative feedbacks are required to destabilize the MJO, in conjunction with weakly positive vertical gross moist stability. It is also hypothesized that horizontal advection is critical to eastward MJO propagation. Specific questions that the proposed work will address include: 1) What combination of processes is responsible for destabilization of the MJO, including vertical advection, surface fluxes, and/or radiative feedbacks? 2) What are the contributions of moisture advection by the mean flow, anomalous flow, and higher frequency disturbances to eastward propagation of the MJO? 3) How do selected process-based metrics inspired by the column-integrated MSE budget relate to model MJO performance, and what do these relationships tell us about MJO dynamics? 4) How does the partitioning of destabilization and propagation factors in the column-integrated MSE budget compare between models and observations, and how do differences in this partitioning relate to model mean state bias?

了解热带季节内变率是气候动力学中的一个重要问题。该项目的目标是加强对Madden-Julian振荡（MJO）的基本动力学的理解。这一努力的广泛影响非常大。PI将与NCAR合作，将新开发的面向过程的诊断纳入诊断包，该诊断包将应用于NCAR的社区地球系统模型（CESM）的不同版本，以评估并最终改进MJO的代表性。此外，将有研究生和博士后培训，以及诊断能力的发展，可用于气候科学界，以潜在地改善模式simulation.The主导的假设，将在这个项目中进行检查是风蒸发和辐射反馈所需的不稳定的MJO，结合弱正垂直总湿稳定度。也有人假设，水平平流是至关重要的向东MJO传播。具体的问题，拟议的工作将解决包括：1）什么样的组合过程是负责不稳定的MJO，包括垂直平流，表面通量，和/或辐射反馈？2)由平均气流、异常气流和高频扰动引起的水汽平流对MJO向东传播的贡献是什么？3)受列集成MSE预算启发而选择的基于流程的指标如何与模型MJO性能相关，这些关系告诉我们关于MJO动态的什么？4)在列综合MSE预算中，模型和观测值之间的不稳定和传播因子的划分如何比较，以及这种划分中的差异如何与模型平均状态偏差相关？