An ice-free Arctic: oceanic and atmospheric mechanism

2005年，北极夏季海冰面积创历史新低。 这是自1979年卫星使天气冰成像成为可能以来，连续第四次创纪录的低点，并结束了近30年的下降趋势。北极气候研究界有一个严肃的猜测，我们，或者可能是我们的孩子，将看到一个无冰的北极作为一个常规的夏季特征。拟议工作的主要目标是澄清海洋和大气在塑造无冰北极方面的作用。该项目还将改善我们对基于大气环流模式（GCM）的当前一代气候预测的解释。首先，将调查北冰洋和北大西洋北方北部之间的淡水和热量交换。我们的目标是：（1）量化表层洋流和海冰对从北极到格陵兰海和拉布拉多海的淡水输送的逐年变化的贡献，（2）更好地理解这种淡水输送与大气强迫之间的联系，特别是大气变化模式，如北大西洋涛动（NAO），（3）量化浮力通量和机械强迫的作用（来自风）在驱动与淡水输出有关的混合层深度的空间变化方面，以及（4）评估目前的GCM模拟被认为对气候变率和高纬度地区变化具有根本重要性的特征的能力，纬度为此，将使用UVic-ESCM耦合冰-海模型进行控制和扰动试验。 它的输出，沿着与其他IPCC-2005运行将比较温度，盐度和示踪剂观测（主要是O 18，C-14，氦-Tr，氟氯化碳）。

The year 2005 marked a record low in summer sea-ice extent in the Arctic.  This is the 4th record low in a row, and caps a nearly 3-decade downward trend, since satellites made synoptic ice imaging possible in 1979. There is serious speculation in the Arctic climate research community that we, or possibly our children, will see an ice-free Arctic as a regular summer feature. The main goal of the proposed work is to clarify the role of the ocean and the atmosphere in shaping an ice-free Arctic. The project will also improve our interpretation of the current generation climate predictions based on General Circulation Models (GCMs). First, the fresh water and heat exchange between the Arctic Ocean and the northern North Atlantic will be investigated. Our goal here is: (1) to quantify the contribution of the surface ocean currents and the sea ice to the year-to-year variability in fresh water transport from the Arctic into the Greenland and Labrador seas, (2) to better understand the link between this fresh water transport and atmospheric forcing, especially atmospheric modes of variability such as the North Atlantic Oscillation (NAO), (3) to quantify the role of buoyancy fluxes and mechanical forcing (from winds) in driving spatial changes to the mixed layer depth which are linked to fresh water export, and (4) to evaluate the ability of current GCMs to simulate features that are believed to be of fundamental importance to climate variability and change in the high latitudes. To this end, the UVic-ESCM coupled ice-ocean model will be used for control and perturbation runs.  Its output, along with other IPCC-2005 runs will be compared with temperature, salinity, and tracer observations (principally O18, C-14, He-Tr, CFCs).