Modeling the impact of polar mesocyclones on ocean circulation
Modeling the impact of polar mesocyclones on ocean circulation
复制标题
模拟极地中气旋对海洋环流的影响
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
I. Renfrew
中科院分区：
文献类型：
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作者：
A. Condron;G. Bigg;I. Renfrew
[1]次天气极地中尺度气旋（或中气旋）在大气再分析数据集中的代表性不足，在大多数用于季节或气候预报的模式中是次网格尺度过程。这种缺乏代表性，特别是在北欧海域，有一个显着的影响，模拟海洋环流，由于在海气边界的大气强迫随之低估。使用朗肯涡和统计上显着的中气旋直径和最大风速之间的线性关系，一种新的参数化开发，允许bogusing在失踪或代表不足的涡利用卫星派生的中气旋数据库。从1993年10月至1995年9月，超过2500个气旋已知是失踪的再分析数据在东北大西洋参数化到强迫场的全球海洋数值模拟实验。这种扰动强迫模拟控制模拟的比较表明，增强表面潜热和感热通量和北欧海环流的气旋旋转的四倍的平均年际变化显着增加。作为对这些变化的响应，格陵兰海深层水（GSDW）的形成通常在1个月内增加20%，表明开放海洋对流更加活跃。然而，这种增加幅度小于全球可持续发展水产量每月的巨大变化。同时，溢出丹麦海峡的中层和深层水的流量增加，突出表明了短暂、强烈的大气活动与深海环流之间的重要联系。参数化方案有可能调整后用于耦合气候模式。
[1] Subsynoptic polar mesoscale cyclones (or mesocyclones) are underrepresented in atmospheric reanalysis data sets and are subgrid scale processes in most models used for seasonal or climate forecasting. This lack of representation, particularly over the Nordic Seas, has a significant impact on modeled ocean circulation due to a consequent underestimation of atmospheric forcing at the air–sea boundary. Using Rankine vortices and a statistically significant linear relationship between mesocyclone diameter and maximum wind speed, a novel parameterization is developed that allows the bogusing in of missing or underrepresented vortices by exploiting a satellite-derived mesocyclone database. From October 1993 to September 1995, more than 2500 cyclones known to be missing from reanalysis data over the northeast Atlantic are parameterized into the forcing fields for a global ocean-only numerical modeling experiment. A comparison of this perturbed forcing simulation to a control simulation shows enhanced surface latent and sensible heat fluxes and a dramatic increase in the cyclonic rotation of the Nordic Seas gyre by four times the average interannual variability. In response to these changes, Greenland Sea Deep Water (GSDW) formation generally increases by up to 20% in 1 month, indicating more active open ocean convection. However such enhancements are smaller than the considerable monthly variability in GSDW production. An accompanying increase in the volume transport of intermediate and deep water overflowing the Denmark Strait highlights an important coupling between short-lived, intense atmospheric activity and deep ocean circulation. The parameterization scheme has the potential to be adapted for use in coupled climate models.