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?

了解热带季节内变异性是气候动态的重要问题。该项目的目的是增强对Madden-Julian振荡（MJO）的基本动态的理解。这项工作的更广泛影响非常高。与NCAR合作，PI将将新开发的面向过程的诊断纳入诊断软件包中，该软件包将应用于NCAR社区地球系统模型（CESM）的不同版本，以评估并最终改善MJO的表示。此外，将有研究生和博士后培训以及诊断能力的发展，气候科学界可以使用这些能力来改善模型模拟。在该项目中将检查的主要假设是，与弱肯定的呈弱的正面验证验证，需要使风蒸发和辐射反馈破坏MJO的稳定。还假设水平对流对东MJO的传播至关重要。拟议工作将解决的具体问题包括：1）哪些过程组合导致MJO的稳定，包括垂直对流，表面通量和/或辐射反馈？ 2）水分对流对平均流量，异常流动以及对MJO向东传播的较高频率干扰的贡献是什么？ 3）由列集成的MSE预算启发的选择基于过程的指标与模型MJO性能有关，这些关系告诉我们有关MJO动态的什么？ 4）在列集成的MSE预算中比较模型和观察结果中的破坏稳定和传播因素的分区与模型平均状态偏见有何关系？