Two types of thermo baric deep convection possible in the Greenland Sea
Two types of thermo baric deep convection possible in the Greenland Sea
复制标题
格陵兰海可能存在两种类型的温压深对流
DOI：
10.1029/2010jc006635
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发表时间：
2011
影响因子：
--
通讯作者：
K
中科院分区：
文献类型：
--
作者：
Akitomo;K
用高分辨率(网格尺寸为1m)的二维模式进行了数值试验，研究了与海水状态方程的非线性有关的开阔大洋深部对流的详细特征，并解释了格陵兰海最近的夏季观测，提出了两种冬季对流类型。当寒冷的淡水(起源于北极)占据地表混合层时，水柱的对流翻转突然发生。热压对流羽流分支成小尺度(∼O(10∼100m))涡流，并在向下的过程中吞没周围的深水。它们引起水性质剖面的显着波动，但不能使倾覆的地层完全均匀。因此，在温度、盐度和位势密度降低的深处，稳定的层结仍然存在。当表面混合层中存在温暖的咸水(起源于大西洋)时，它会通过表面冷却而加深，有力地卷进下面的水。在加深的混合层中，水的性质几乎是均匀的，具有与第一种情况相反的特征。这些结果支持这样一种推断，即在格陵兰海观察到的两种不同的水性质剖面是两种类型的深对流的特征。
A numerical experiment has been executed with a fine‐resolution (grid size of 1 m), two‐dimensional model to investigate detailed features of open ocean deep convection related to the nonlinearity of the equation of state for seawater and to interpret recent summer observations in the Greenland Sea, suggesting two types of winter convection. When cold, fresh waters (Arctic origin) occupy the surface mixed layer, convective overturning of the water column occurs abruptly. Thermobaric convective plumes branch into small‐scale (∼O(10 ∼ 100 m)) eddies and engulf ambient deep water on the way down. They induce significant fluctuations in profiles of water properties but do not homogenize the overturned layer completely. As a result, stable stratification remains at depths where temperature, salinity, and potential density decrease. When warm, saline waters (Atlantic origin) exist in the surface mixed layer, it deepens by surface cooling, entraining the underlying water vigorously. Water properties are nearly homogenized in the deepening mixed layer and have opposite features to the first case. These results support a deduction that two different profiles of water properties observed in the Greenland Sea are signatures of two types of deep convection.