An improved single-column model representation of ocean mixing associated with summertime leads: Results from a SHEBA case study
An improved single-column model representation of ocean mixing associated with summertime leads: Results from a SHEBA case study
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DOI：
10.1029/2002jc001557
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发表时间：
2003-04
影响因子：
--
通讯作者：
M. Holland
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文献类型：
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作者：
M. Holland
[1]1998年7月5日至8月8日，为SHEBA实地项目案例研究进行了冰/海洋混合层模型模拟。观测结果表明，在此期间，出现了平静的风，同时SHEBA营地附近的铅表面迅速变暖和清新。随后的风暴混合了这些温暖的淡水。这一事件的单柱模型模拟进行隔离的海洋系统，必须考虑到，以提高夏季铅混合的代表性的属性。一个传统的方法模拟冰/海洋系统，其中一个单一的海洋混合层计算被迫与通量聚集在冰和开放水域部分的域进行比较，其中单独的混合层计算的铅和冰下海洋系统的模拟。结果发现，不仅是多个海洋混合层的计算需要提高模拟，但铅的表面必须现实地嵌入在冰盖。当出现稳定条件时，铅表面保持与冰下系统隔离。使用这种方法大大改善了模拟铅的垂直温度和盐度分布，使铅表面新鲜到20 ppt，并达到高于冰点1.4°C的温度。这改变了冰的质量预算，增加了横向融化率，开放水域的形成和吸收太阳辐射的量。这对准确模拟气候变化和变率有影响，因为它对气候反馈机制有影响。
[1] Ice/ocean mixed layer model simulations are run for a SHEBA field project case study from 5 July–8 August 1998. Observations indicate that during this time, calm winds occurred and coincided with a rapid warming and freshening of the surface of a lead near the SHEBA camp. A subsequent storm mixed down this warm, fresh water. Single-column model simulations of this event are performed to isolate properties of the ocean system which must be accounted for to improve the representation of mixing in summertime leads. A traditional method of simulating the ice/ocean system in which a single ocean mixed layer calculation is forced with fluxes aggregated over the ice and open water portions of the domain is compared with simulations in which separate mixed layer calculations are done for the lead and under-ice ocean systems. It is found that not only are multiple ocean mixed layer calculations needed to improve the simulations but the surface of the lead must be realistically embedded within the ice cover. When stable conditions occur, the lead surface remains isolated from the under-ice system. Using this method considerably improves simulated lead vertical temperature and salinity profiles, allowing the lead surface to freshen to 20 ppt and reach temperatures greater than 1.4°C above freezing. This modifies the ice mass budgets, increasing lateral melt rates, open water formation, and the amount of absorbed solar radiation. This has implications for the accurate simulation of climate change and variability due to its effects on the albedo feedback mechanism.