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: 0960648
• 负责人: Kathryn Kelly
• 金额: $ 35.16万
• 依托单位: University of Washington
• 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 2015-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0960648&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）是西部边界流（WBC）赤道侧响应冬季降温而形成的等温层，对理解中纬度地区气候变率至关重要，因为它整合了海洋和大气的异常，有助于气候系统记忆。STMW区域具有较大的储热能力，其储热率已被证明取决于海气通量和海洋环流。STMW的体积如此之大，仅靠几年的海气相互作用无法消散它；在形成后，在随后的冬季，它会部分地被重新吸收，再次与大气相互作用。已经确定了许多可能影响STMW形成或随后破坏的过程。美国国家科学基金会资助的CLIMODE （CLIVAR模式水实验）的一个主要目标是量化北大西洋西部STMW的演变过程，通常被称为18度水（EDW），因为它的温度几乎恒定。在为期两年的实地项目中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对EDW演化有贡献的过程的相对重要性。一个主要动机是CLIMODE分析将导致气候模拟的改进。本研究旨在提供climode特定分析、较长时期变率以及评估和验证气候模式所需指标之间的联系。知识价值：EDW区域具有巨大的热量储存和海气通量，可变的极向热输送和高能海洋环流，是大气-海洋系统中记忆的主要候选者。拟议的研究是对EDW体积的年际至十年变化、导致其变化的过程及其对海气相互作用的影响的检查。EDW演变中的一些竞争过程（暖流平流、混合和海气通量造成的海洋热损失）与北大西洋涛动等气候指数有关。研究人员将研究是否可以使用代理变量来监测重要过程，从而将现场程序结果与更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。更广泛的影响：为了成功地预测气候变率和变化，模式必须能够模拟那些产生年际到十年气候影响的过程。一个有效的气候观测系统必须监测表征这些基本过程所需的变量，并改进模式参数化和模拟。例如，EDW地区是中纬度风暴快速增强的中心，这可能是对海洋条件变化的反应，特别是对海洋储热的反应。气候预测（如风暴强度的变化）的模拟和验证依赖于开发一系列衡量模型模拟重要过程（热储存）的效果的指标。对于对EDW演变及其气候影响至关重要的过程，将确定关键测量方法，以便制定简单而适当的指标来评估气候模型。该项目是对美国CLIVAR（气候变率和可预测性）计划的贡献。