Atmospheric Forcing of Marginal-Sea Overflows

边缘海溢流的大气强迫

• 批准号: 0927017
• 负责人: Jiayan Yang
• 金额: $ 59.72万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2013-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0927017&HistoricalAwards=false
• 关键词: Atmospheric; Forcing; Marginal; Sea; Overflows

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The atmospheric forcing of marginal-sea overflows will be investigated. The main motivation is the need to develop better parameterizations of marginal sea outflows of all scales and also from observations of the Nordic Seas overflows showing considerable interannual variability of transport and water temperature, possibly linked to the North Atlantic Oscillation (NAO). The observed variations would be difficult to explain using standard hydraulics models alone, but could be captured in models that combine atmospheric forcing, hydraulic processes and a consideration of the circulation in the marginal sea. As a first step, a new analytic model for a marginal sea outflow that includes atmospheric forcing and time dependence will be developed. The model will predict the lower layer outflow properties of the two-layer exchange given the forcing and the upper layer inflow temperature and salinity. It should be applicable to marginal seas and straits of scales varying from the Med/Gibraltar systems to the Nordic Seas and should be superior to existing parameterizations used in some general circulation models. A hierarchy numerical modeling simulations using both idealized and realistic bathymetry will be conducted to examine the impacts of atmospheric forcing, such as NAO, on the overflow, and to identify mechanisms responsible for the timing and amplitude of observed changes of the overflow. The numerical modeling component will be focused on the Nordic overflows. The hypothesis that the atmospheric forcing over the Nordic Seas is the primary cause for interannual Nordic Seas overflow variability will tested. Alternative ways of monitoring the deep overflows will also be investigated. The ultimate goal is to understand how the overflow and the Atlantic Meridional Overturning Circulation (AMOC) respond to a changing climate.Intellectual Merit:This study will advance our understanding of the Nordic Seas overflow and its responses to climate forcing, provide a climate-responsive marginal-sea boundary condition (MSBC) that is more advanced than the Price-Yang version used in several climate models, help understand AMOC variability in model simulations, and help improve the predictability of AMOC's responses to a changing climate.Broader Impacts:The Nordic Seas region is an important player in the global ocean climate puzzle. A better understanding of the response of the deep outflows to changing forcing will ultimately help predict the global effects of warming, glacier melt, and other environmental changes in the Nordic regions.In terms of outreach activities, investigator Pratt has given presentations to high school students at a local school (Cape Cod Academy). The subject material of this project (marginal seas, overflows, and the abyssal circulation) should be fascinating to students of that age and we plan to go back into the classroom and talk about it. Plans are coordinated through Cathy Cetta, assistant headmaster and teacher at CCA. Investigator Pratt also plans to build on the educational impact of his text book by developing online aids such as additional homework exercises and movies.This project is a contribution to the Atlantic Meridional Overturning Circulation research theme under the U.S. CLIVAR (CLImate VARiability and predictability) Program.

该奖项是根据2009年美国复苏和再投资法案(公法111-5)资助的。将调查边缘海溢出的大气强迫。主要动机是需要更好地对所有尺度的边际海洋外流进行参数化，并通过对北欧海溢流的观测，发现输送和水温有相当大的年际变化，这可能与北大西洋涛动有关。仅用标准水力学模型很难解释观测到的变化，但可以通过结合大气强迫、水力过程和考虑边缘海环流的模型来捕捉。作为第一步，将建立一个新的边际海洋外流分析模式，该模式包括大气强迫和时间相关性。在给定强迫和上层入流温度和盐度的情况下，该模式将预测两层交换的下层流出特性。它应适用于从地中海/直布罗陀系统到北欧海洋的边缘海和比例尺不等的海峡，并应优于一些大气环流模式中使用的现有参数化。将使用理想和现实的水深测量进行分级数值模拟模拟，以检查大气强迫(如NAO)对溢流的影响，并确定导致观测到的溢流变化的时间和幅度的机制。数值模拟部分将侧重于北欧溢流。北欧海域的大气强迫是北欧海域年际溢出变化的主要原因的假设将得到检验。还将调查监控深度溢出的替代方法。最终目标是了解溢出和大西洋子午线翻转环流(AMOC)如何响应变化的气候。智力价值：这项研究将促进我们对北欧海洋溢出及其对气候强迫的响应的理解，提供一个比几个气候模式中使用的普赖斯-杨版本更先进的气候响应边缘海边界条件(MSBC)，帮助理解AMOC在模式模拟中的可变性，并帮助提高AMOC对气候变化的响应的可预测性。更好地了解深度外流对变化强迫的反应最终将有助于预测北欧地区变暖、冰川融化和其他环境变化的全球影响。在外展活动方面，调查员普拉特在当地一所学校(科德角学院)向高中生做了报告。这个项目的主题材料(边缘海、溢流和深海环流)应该对那个年龄的学生很有吸引力，我们计划回到教室里谈论它。通过CCA的助理校长兼教师Cathy Cetta协调计划。研究人员普拉特还计划通过开发额外的作业练习和电影等在线辅助工具来加强他的教科书的教育影响。该项目是对美国CLIVAR(气候可变性和可预测性)计划下的大西洋子午线颠覆环流研究主题的贡献。