The Mutual Interaction Between Ice Production and Ocean Heat Transport in a Greenhouse Warming Scenario

温室变暖情景下产冰与海洋热传输之间的相互作用

• 批准号: 0454843
• 负责人: Cecilia Bitz
• 金额: $ 32.44万
• 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: 2005
• 资助国家: 美国
• 起止时间: 2005-03-01 至 2009-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0454843&HistoricalAwards=false
• 关键词: Mutual; Interaction; Between; Ice; Production

Most global climate models predict an increase in the northward oceanic heat transport north of about 60 N in future climate scenarios as compared to the present day. This increase in heat transport is reminiscent of explanations posed for recent observed warming in the Atlantic layer in the western Eurasian Basin of the Arctic Ocean. An implication is that warmings like those that occurred in the recent past, which have been attributed to wind variations by some, could also occur in the future due to greenhouse gas forcing.This work hypothesizes that the increase in heat transport in the future greenhouse scenario is in response to the transition from perennial to first year ice in the Barents Sea and Arctic Ocean, and the attendant increase in heat loss and brine rejection in fall and winter. Sea ice production rejects brine, driving gravitational convection, which creates dense shelf waters and encourages heat and mass exchange from the Atlantic layer to the surface. If the hypothesis is correct, the ice production-heat transport interaction must outweigh the increase in stability from increased precipitation and runoff in the Arctic in a warmer climate. Such a mechanism would further accelerate the transition from perennial to first year ice and reduce the overall sea ice cover in the future.Simulations with the Community Climate System Model Version 3 (CCSM3), a fully coupled atmosphere-ocean model that explicitly resolves the sea ice thickness distribution, show that northward oceanic heat transport (and the meridional overturning circulation) peak at about the same time that ice production peaks in the Arctic Ocean in a future scenario. This is a two part study: the first objective is to investigate the reason that heat transport increases into the Nordic Seas and Arctic Ocean in future scenarios with global climate models and assess the consequences of this increase for the sea ice cover. The second objective is to understand the sensitivity of the sea ice thickness distribution to increased greenhouse gases, and its relation, if any, to the increase oceanic heat transport into the Arctic in future climate change scenarios. This investigation of a positive feedback between sea ice-ocean system may explain the increase in oceanic heat transport into the Arctic that is seen in greenhouse warming scenarios with climate models. A transformation from perennial sea ice to first year sea ice in the Arctic, and the attendant increase in ice production is the first step of the feedback process. This work will also develop a general method for predicting the change in the ice thickness distribution in response to a climate perturbation.

与今天相比，大多数全球气候模型预测，在未来气候情况下，在未来的气候情况下，向北的海洋热传输北部大约60 n。热运输的增加让人联想到最近在北极海洋西部欧亚盆地的大西洋层中观察到的变暖提出的解释。一个暗示是，像最近发生的那些发生的热量一样，由于某些人的风变化，这也可能在未来由于温室气体强迫而发生。这项工作假设，将来的温室场景中的热量增加是响应于从多年生的冰上过渡到Barents Sea and Arctic and Arctic Ocean和Alctic Ocean and Brine and Brine and Brine and Brine and Brine and Brine and Brine and Brine and Brine and Brine and Brine and Brine and Brine and Brine and Brine and Brine and Brine and Brine and Brine and Brine and Brine and Brine and Brine and Brine and Brine。海冰生产拒绝盐水，驱动引力对流，从而产生密集的架子水，并鼓励从大西洋层到地面的热量和大规模交换。如果假设正确，则在温暖的气候下北极的降水量和径流增加，冰生产热的交流必须超过稳定性的提高。这种机制将进一步加速从多年生冰到第一年的过渡并减少未来的整体海冰覆盖。与社区气候系统模型3（CCSM3）相似，这是一个完全耦合的大气 - 大小模型，明确地分辨了海冰厚度，它可以使海洋的高峰（冰上的峰值）（在冰上达到高峰），这是冰的高峰（冰上），这是冰的高峰（冰上的峰值）。 设想。这是一项两部分研究：第一个目的是研究在未来的情况下，使用全球气候模型在将来的情况下，热运输会增加到北欧海洋和北极海洋的原因，并评估这种增加对海冰覆盖的后果。第二个目标是了解海冰厚度分布对增加温室气体的敏感性及其关系（如果有的话），将海洋热量增加在未来的气候变化情况下向北极增加了海洋热量。对海冰海洋系统之间积极反馈的调查可能会解释海洋热传输到北极的增加，这在带有气候模型的温室变暖场景中可以看到。从多年生海冰到北极的第一年海冰的转变，以及冰产量的随之而来的增加是反馈过程的第一步。这项工作还将开发一种通用方法，以预测因气候扰动而响应的冰厚度分布的变化。