Collaborative Research: Gas Transfer through Polar Sea Ice (GAPS) - Mechanisms of Turbulence Production in the Seasonal Ice Zone and its Control of Mixed Layer Ventilation

合作研究：极地海冰气体传输（GAPS）——季节性冰区湍流产生机制及其对混合层通风的控制

• 批准号: 0944643
• 负责人: Peter Schlosser
• 金额: $ 46.03万
• 依托单位: Columbia University
• 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: 2010-10-01 至 2013-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0944643&HistoricalAwards=false
• 关键词: Collaborative; Research; Gas; Transfer; through

AbstractHigh latitude ocean and sea ice surface fluxes of heat, momentum, fresh water and radiatively important gases such as carbon dioxide are critical to understanding polar, and thus global, climate processes. Field observations of these fluxes, and the physics and biogeochemistry that control them is hampered alternately by both the high winds and sea states typical of polar seas, and the complex potentially non-linear transport pathways between water, ice and air during conditions of active freezing and partial sea-ice cover. This project will study, in a unique controlled laboratory facility, the relative contribution of the physical processes that regulate gas exchange through sea ice.A seasonal evolution cycle of different sea-ice types found in the ice pack, namely 1) pancake ice, 2) complete ice cover, but with leads (openings), and 3) melted ice floes with a freshwater lens, will be simulated in a well controlled laboratory setting. Additionally, different turbulence regimes of wind, wave effects, convection and ice-water current shear at various levels of freezing will be studied in the CRREL sea ice pond facility (New Hampshire). Potentially transformative nature of this research The physics, and biogeochemistry of air-sea flux exchanges in heterogeneous and multi featured environment such as sea-ice is extremely challenging for any existing theory or computational approach. The observational approach that the investigators are using, introduction of chemically inert gases as deliberate tracers, has the ability to account for several different limiting steps encountered in gas exchange through sea ice. A multi-tracer (e.g. SF6, He, Ar, CO2...) mass balance approach has been used and refined by these investigators over the course of prior field campaigns at less challenging and more conventional air-sea boundaries. Preliminary results used to investigate the ice pond experimental approach have indicated that gas exchange through sea-ice does not scale with the amount of open water, negating what otherwise appeared to be a reasonable approximation. The resulting parameterization to be revealed by such studies may suggest redirection as to what really are the rate limiting steps of sea-ice flux transfers. These processes are important for accurate coupled Earth System Models of climate change.

纬度海洋和海冰表面的热量、动量、淡水和辐射重要气体（如二氧化碳）通量对于理解极地乃至全球气候过程至关重要。这些通量的实地观测以及控制它们的物理和生物地球化学交替受到极地海洋典型的大风和海况以及在活跃冻结和部分海冰覆盖条件下水、冰和空气之间复杂的潜在非线性运输途径的阻碍。该项目将在一个独特的受控实验室设施中研究通过海冰调节气体交换的物理过程的相对贡献。在一个控制良好的实验室环境中，将模拟在浮冰中发现的不同海冰类型的季节性演变周期，即1)煎饼冰，2)完整的冰盖，但有引线（开口），以及3)有淡水透镜的融化浮冰。此外，将在CRREL海冰池设施（新罕布什尔州）研究不同冻结水平下的风、波效应、对流和冰水切变的不同湍流状态。在非均质和多特征环境（如海冰）中海气通量交换的物理和生物地球化学对任何现有的理论或计算方法都是极具挑战性的。研究人员使用的观察方法，即引入化学惰性气体作为示踪剂，能够解释通过海冰进行气体交换时遇到的几种不同的限制步骤。多示踪剂（如SF6、He、Ar、CO2等）质量平衡方法已被这些研究人员在之前的现场活动中使用并改进，这些活动具有较低的挑战性和更传统的海气边界。用于研究冰塘实验方法的初步结果表明，通过海冰的气体交换不随开放水域的数量成比例，从而否定了原本看似合理的近似。这些研究所揭示的参数化结果可能表明，海冰通量转移的真正限制速率的步骤是什么。这些过程对于气候变化的精确耦合地球系统模式是重要的。