Simulated heat flux and sea ice production at coastal polynyas in the southwestern Weddell Sea
Simulated heat flux and sea ice production at coastal polynyas in the southwestern Weddell Sea
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DOI：
10.1002/jgrc.20133
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发表时间：
2013-05-01
影响因子：
3.6
通讯作者：
Timmermann, R.
中科院分区：
文献类型：
--
作者：
Haid, V.;Timmermann, R.
沿海冰间湖是冰覆盖海洋中的区域，冰盖主要通过近海风输出。由此产生的海冰减少可以增强海洋与大气的热传递。一旦水温达到冰点，进一步的热量损失就会导致海冰产生。使用有限元海冰海洋模型解决了威德尔海西南部沿海冰间湖的热交换和产冰问题，该模型是一种原始方程静水海洋环流模型，与动态热力学海冰模型相结合，可以量化与水柱冷却相关的热量。确定了三个重要的冰间湖区域：布伦特冰架、罗纳冰架和南极半岛南部。多年冬季平均值（1990 年 5 月至 2009 年 9 月）向大气层提供的向上热通量在布伦特冰间湖为 311W/m(2)，在龙恩冰间湖为 511W/m(2)，在南极半岛冰间湖为 364W/m(2)，其中 57W/m(2)、49W/m(2) 和48W/m(2) 分别由更深层的海洋热通量提供。布伦特冰间湖的平均冬季海冰产量为 7.2 厘米/天，相当于 1.3 x10(10)m(3)/冬季的冰量；龙纳冰间湖的平均冬季海冰产量为 13.2 厘米/天（4.4 x10(10)m(3)/冬季）；南极半岛冰间湖的平均冬季海冰产量为 9.2 厘米/天（2.1 x10(10)m(3)/冬季）。冰间湖内部大气的热通量比邻近区域的热通量高7至9倍；冰间湖单位面积的产冰量是相邻数值的 9 至 14 倍。
Coastal polynyas are areas in an ice-covered ocean where the ice cover is exported, mostly by off-shore winds. The resulting reduction of sea ice enables an enhanced ocean-atmosphere heat transfer. Once the water temperatures are at the freezing point, further heat loss induces sea ice production. The heat exchange and ice production in coastal polynyas in the southwestern Weddell Sea is addressed using the Finite-Element Sea-ice Ocean Model, a primitive-equation, hydrostatic ocean circulation model coupled with a dynamic-thermodynamic sea-ice model, which allows to quantify the amount of heat associated with cooling of the water column. Three important polynya regions are identified: at Brunt Ice Shelf, at Ronne Ice Shelf and along the southern part of the Antarctic Peninsula. Multiyear winter means (May-September 1990-2009) give an upward heat flux to the atmosphere of 311W/m(2) in the Brunt polynyas, 511W/m(2) in Ronne Polynya and 364W/m(2) in the Antarctic Peninsula polynyas, whereof 57W/m(2), 49W/m(2) and 48W/m(2), respectively, are supplied as oceanic heat flux from deeper layers. The mean winter sea ice production is 7.2 cm/d in the Brunt polynyas corresponding to an ice volume of 1.3 x10(10)m(3)/winter, 13.2 cm/d at Ronne polynya (4.4 x10(10)m(3)/winter), and 9.2 cm/d in the Antarctic Peninsula polynyas (2.1 x10(10)m(3)/winter). The heat flux to the atmosphere inside polynyas is 7 to 9 times higher than the heat flux in the adjacent area; polynya ice production per unit area exceeds adjacent values by a factor of 9 to 14.