The Role of Inertial Instability and Boundary-Layer Processes in Equatorial Monsoon Regions

赤道季风区惯性不稳定和边界层过程的作用

• 批准号: 0741832
• 负责人: Gad Levy
• 金额: $ 41.18万
• 依托单位: NorthWest Research Associates, Incorporated
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-01-01 至 2011-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0741832&HistoricalAwards=false
• 关键词: Role; Inertial; Instability; Boundary; Layer

Much of the rain that falls in the deep tropics is concentrated in the inter-tropical convergence zone (ITCZ). The dynamics that determine the distribution of convective rainfall near the equator, such as the position of the inter-tropical convergence zone (ITCZ), are not well understood. Global climate models (GCMs) often fail to capture the observed distribution, and it is sensitive to details of model parameterizations. Observational evidence suggests that a fundamental fluid dynamical instability, inertial instability, is important for this problem. Here the problem of the position of the ITCZ will be addressed by focusing on the role of inertial instability within the boundary layer - the atmospheric layer near the ground - and interactions between inertial instability and boundary-layer turbulence and convection. Dynamical hypotheses will be tested using boundary-layer parameterizations driven by data. The key data are scatterometer (QuikSCAT) derived winds and wind stresses. Processes inferred from the observational studies will be tested in a set of model experiments.Three major tasks will be carried out:1) Analyses of observational data to investigate the relationship between the inertial instability - specifically the location of the line of zero absolute vorticity - and the location of the ITCZ.2) Analyses of the force balances within the boundary layer, and the transition from advective to Ekman (drag dominated) regimes across the line of zero absolute vorticity. 3) Analyses of the time scales of inertial instability and the processes that contribute to the position of the ITCZ on different timescalesBroader impacts of this research are in its potential to drive improved representations of tropical circulations in global models, improved understanding of the Indian monsoon and of the genesis of tropical cyclones, and in the application of some methods to related problems that involve modeling sub-grid scale processes. A new investigator will be trained and an undergraduate will participate in the research through cooperation with the University of Washington.

深层热带地区的许多降雨集中在热带融合区（ITCZ）。确定赤道附近对流降雨分布的动力学，例如热带融合区（ITCZ）的位置，尚不清楚。全球气候模型（GCM）通常无法捕获观察到的分布，并且对模型参数化的细节很敏感。观察性证据表明，基本的流体动力学不稳定性，惯性的不稳定性对于这个问题很重要。在这里，ITCZ位置的问题将通过关注边界层内惯性不稳定的作用 - 地面附近的大气层 - 惯性不稳定与边界层湍流和对流之间的相互作用。动态假设将使用由数据驱动的边界层参数化测试。关键数据是散射仪（Quikscat）衍生的风和风应力。 Processes inferred from the observational studies will be tested in a set of model experiments.Three major tasks will be carried out:1) Analyses of observational data to investigate the relationship between the inertial instability - specifically the location of the line of zero absolute vorticity - and the location of the ITCZ.2) Analyses of the force balances within the boundary layer, and the transition from advective to Ekman (drag dominated) regimes across the line零绝对涡度。 3）分析惯性不稳定的时间尺度以及有助于ITCZ对这项研究的不同时间标度的影响的过程的分析，其潜力有可能提高全球模型中热带循环的改善表示，改善对印度季风的理解以及对热带cyclone的形成范围以及与某些方法相关的应用程序的应用程序，并涉及与某些方法相关的范围。将培训一名新的调查员，并通过与华盛顿大学的合作参加研究生。