Collaborative Research: Dynamics of Eighteen Degree Water from CLIMODE Observations and its Climate Implications

合作研究：CLIMODE 观测中的 18 度水动态及其对气候的影响

• 批准号: 0958548
• 负责人: Shenfu Dong
• 金额: $ 25.47万
• 依托单位: University of Miami
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-04-01 至 2014-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0958548&HistoricalAwards=false
• 关键词: Collaborative; Research; Dynamics; Eighteen; Degree

Subtropical Mode Water (STMW), an isothermal layer that forms on the equatorward side of western boundary current (WBC) in response to wintertime cooling, is central to understanding climate variability in mid-latitude regions because it integrates anomalies in both the ocean and atmospheric to contribute to climate system memory. The STMW region has a large capacity to store heat, and its heat storage rate has been shown to depend both on air-sea fluxes and on ocean circulation. The volume of STMW is so large that several years of air-sea interaction alone cannot dissipate it; after formation, it is partially re-entrained in subsequent winters to again interact with the atmosphere.Many processes have been identified that could affect STMW formation or its subsequent destruction. A primary goal of the NSF-funded CLIMODE (CLIVAR Mode Water Experiment) is to quantify the processes contributing to the evolution of the STMW of the western North Atlantic, commonly referred to as 18-degree-water (EDW) because of its nearly constant temperature. An extensive set of measurements has been obtained over the two-year field program; analyses and modeling of the observational period can help evaluate the relative importance of the processes contributing to EDW evolution. A primary motivation is that CLIMODE analyses will lead to improvements in climate modeling. This study aims to provide a link between the CLIMODE-specific analyses, longer period variability, and the need for metrics to evaluate and verify climate models. Intellectual merit: The EDW region with its large heat storage and air-sea fluxes, variable poleward heat transport, and energetic ocean circulation is a prime candidate for memory in the atmosphere-ocean system. The proposed research is an examination of the interannual-to-decadal variations in EDW volume, of the processes that contribute to it, and its impact on air-sea interaction. Some competing processes in EDW evolution (warm water advection by the Gulf Stream, mixing, and oceanic heat loss through air-sea fluxes) have variability linked to climate indices such as the North Atlantic Oscillation. The investigators will examine whether important processes can be monitored using proxy variables and thus link the field program results to the longer climate record to evaluate the importance of each process, the predictability of EDW evolution, and the ability of EDW to contribute to climate memory.Broader impacts: To be successful in predicting climate variability and change, models must be able to simulate those processes that produce interannual-to-decadal climate impact. An effective climate observing system must monitor the variables needed to characterize those fundamental processes and improve model parameterization and simulation. For example, the EDW region is a center of rapid intensification of mid-latitude storms that may be responding to changing ocean conditions, in particular, to ocean heat storage. Simulation and verification of climate predictions (such as changes in storm intensity) depend on developing a series of metrics that measure how well the model simulates important processes (heat storage). For the processes that are important to EDW evolution and its climate impact, critical measurements will be identified in order to develop simple and appropriate metrics with which to evaluate climate models.This project is a contribution to the U.S. CLIVAR (CLImate VARiability and predictability) program.

副热带模态水（STMW），一个等温层，形成在赤道一侧的西部边界流（WBC）在冬季冷却，是理解中纬度地区的气候变率的核心，因为它集成了异常的海洋和大气，有助于气候系统的记忆。STMW区域有很大的储热能力，其储热率已被证明取决于海气通量和海洋环流。短期低分子量物质的体积很大，仅凭几年的海气相互作用是无法将其消散的;形成后，在随后的冬季，它会被部分重新携带，再次与大气相互作用，已查明有许多过程可能影响短期低分子量物质的形成或随后的破坏。美国国家科学基金会资助的CLIMODE（CLIVAR模式水实验）的主要目标是量化有助于北大西洋西部STMW演变的过程，通常被称为18度水（EDW），因为它几乎恒定的温度。在为期两年的实地项目中，已经获得了一系列广泛的测量结果;对观测期的分析和建模可以帮助评估有助于EDW演变的过程的相对重要性。一个主要的动机是CLIMODE分析将导致气候建模的改进。这项研究的目的是提供一个链接CLIMODE特定的分析，较长的周期变率，并需要指标来评估和验证气候模式。智力优点：EDW区域具有巨大的热储存和海气通量，多变的极向热输送和高能海洋环流，是大气-海洋系统记忆的主要候选者。拟议的研究是一个检查的年际到十年变化的EDW量，的过程，有助于它，以及它对海气相互作用的影响。EDW演变中的一些竞争过程（墨西哥湾流的暖水平流，混合和通过海气通量的海洋热损失）与气候指数（如北大西洋涛动）有关。研究人员将检查是否可以使用代理变量来监测重要的过程，从而将实地项目结果与较长的气候记录联系起来，以评估每个过程的重要性、EDW演变的可预测性以及EDW对气候记忆的贡献能力。为了成功地预测气候变率和变化，模型必须能够模拟产生年际至十年气候影响的过程。有效的气候观测系统必须监测描述这些基本过程所需的变量，并改进模型参数化和模拟。例如，EDW地区是中纬度风暴快速增强的中心，这些风暴可能对不断变化的海洋条件，特别是海洋热储存做出反应。气候预测的模拟和验证（如风暴强度的变化）取决于开发一系列衡量模型模拟重要过程（热储存）的指标。对于EDW演变及其气候影响的重要过程，将确定关键的测量结果，以开发简单而适当的度量标准来评估气候模型。该项目是对美国CLIVAR（CLImate VARiability and predictability）计划的贡献。