Dynamics of Basin-Scale Arctic Ocean Circulation

北冰洋大尺度海洋环流的动力学必然与任何低纬洋盆有很大的不同，因为构成盆地尺度环流前序动力学的两个过程，即(1)由Ekman抽吸驱动的Sverdrup流和(2)关闭涡旋环流并驱散风应力的涡量通量的西边界层流不适用于北冰洋。这是因为(=df/dy，其中f是科里奥利参数)几乎为零，以及北冰洋没有西部边界。尽管模拟能力发展迅速，但对支配北极地区盆地尺度海洋环流及其变异性的动力学的基本了解仍有待发展。为使用面向流程的模式解决这一问题提供了资金。项目的目标是了解(1)哪些过程平衡海洋内部的表面强迫；(2)表面应力卷曲产生的涡量通量如何消散以及在哪里消散，以便能够维持准稳定环流；(3)在行星Rossby波因接近零而停滞的环境中，北冰洋如何对强迫场的变化作出反应；(4)边界流在建立盆地尺度环流中的作用；以及(5)海底地形的影响。我们将研究风力驱动的环流和温盐环流。国际和平研究所计划使用尽可能简单但又足够的模型来解决这些问题。然而，结果将通过与一个主要的北冰洋模拟联盟合作，在海洋大气环流模型(OGCM)中进行测试。国际海洋研究所和领导北冰洋模式对比项目(AOMIP)的A.ProShuinsky博士(也在WHOI)同意密切合作，在AOMIP目前运行的各种OGCM中测试这项以过程为导向的研究结果。一个成功的项目的结果将有助于指导北冰洋环流预测模型的开发、解释和验证。除其他应用外，这种模型对于预测气候变化和污染物的传输路径是必要的。

The dynamics of large-scale ocean circulation in the Arctic must be very different from that in any lower-latitude ocean basin since the two processes that constitute the leading order dynamics of a basin-scale circulation, i.e., (1) the Sverdrup flow driven by Ekman pumping/sucking and (2) a western boundary layer current that closes the gyre circulation and dissipates the vorticity flux from wind stress, cannot apply to the Arctic Ocean. This is due to the fact that (= df/dy where f is the Coriolis parameter) is nearly zero and to the lack of a western boundary in the Arctic Ocean. Despite the rapid development of modeling capability, a basic understanding of the dynamics that govern the basin scale ocean circulation and its variability in the Arctic has yet to be developed. Funds are provided to address this issue using process-oriented models. The project objectives are to understand (1) which processes balance the surface forcing in the ocean interior; (2) how and where the vorticity flux from the curl of surface stress is dissipated so that a quasi-steady circulation can be maintained; (3) how the Arctic Ocean responds to changes in the forcing field in an environment where planetary Rossby waves are stagnant due to approaching zero; (4) the role of boundary currents in establishing the basin-scale circulation; and (5) the effects of bottom topography. Both wind-driven and thermohaline circulation will be studied. The PI plans to use the simplest possible, yet adequate, models to address each of these issues. The results, however, will be tested in Ocean General Circulation Models (OGCMs) through collaboration with a major Arctic Ocean modeling consortium. The PI and Dr. A. Proshutinsky (also at WHOI), who leads the Arctic Ocean Model intercomparison Project (AOMIP), which focuses on the development of 3-D OGCMs, have agreed to work closely for testing the results from this process-oriented study in various OGCMs that AOMIP is currently running. The results of a successful project will help guide development, interpretation, and verification of predictive models of Arctic Ocean circulation. Such models are necessary for the prediction of climate change and pollutant transport pathways, amongst other applications.