NEMO-ICB (v1.0): interactive icebergs in the NEMO ocean model globally configured at eddy-permitting resolution
NEMO-ICB (v1.0): interactive icebergs in the NEMO ocean model globally configured at eddy-permitting resolution
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DOI：
10.5194/gmd-8-1547-2015
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发表时间：
2015-01-01
影响因子：
5.1
通讯作者：
Zalesny, V. B.
中科院分区：
文献类型：
--
作者：
Marsh, R.;Ivchenko, V. O.;Zalesny, V. B.
一个既定的冰山模块，ICB，交互使用与欧洲海洋模拟核心（NEMO）海洋模型在一个新的实施，NEMO-ICB（v1.0）。一个30年的后报（1976-2005年）模拟与涡流允许（0.25度）的全球配置的NEMO-ICB进行评估冰山对海冰，水文，混合层深度（MLDs），和洋流的影响，通过比较与控制模拟，其中相当于冰山质量通量应用为沿海径流，一种常见的强迫海洋模型。在南半球（SH），冰山的漂移和融化在大约5年后达到平衡，而北方半球（NH）的平衡时间尺度为15-20年。冰山漂移模式和南大洋冰山质量与现有的观测结果相比是有利的。冰山融化造成的淡水强迫在南极洲大部分地区的沿海地区最为明显，在那里，它往往超过与海冰冻结相关的负淡水通量。然而，在南大洋极地的大多数地方，由于冰山（如果存在的话）造成的年平均淡水通量通常比海冰融化和降水的贡献小一个数量级。一个值得注意的例外是南大洋的西南大西洋部分，那里的冰山融化达到了大面积净降水量的50%左右。包括冰山代替沿海径流在内，南极洲周围大部分地区的海冰浓度和厚度明显减少，在威德尔海东部减少了20%，在别林斯高晋海增加了10%。南极海冰总体减少2.9%。由于净淡水强迫和海冰的变化，盐度和温度分布也发生了重大变化。南极洲大部分地区的表面盐度增加到0.1 psu左右，这是由于沿海径流受到抑制，在深度上有广泛的淡化作用，延伸到极地南大洋的最深处，在那里，威德尔海的盐度和温度都受到明显的影响，在模拟的最后五分之一达到2500米。从高纬度到低纬度的密度异常的快速传播解释了全球海洋对冰山的大量物理和动力反应。作为对这里使用的基线模型的补充，还介绍和讨论了NEMO-ICB的三个原型修改。
An established iceberg module, ICB, is used interactively with the Nucleus for European Modelling of the Ocean (NEMO) ocean model in a new implementation, NEMO-ICB (v1.0). A 30-year hindcast (1976-2005) simulation with an eddy-permitting (0.25 degrees) global configuration of NEMO-ICB is undertaken to evaluate the influence of icebergs on sea ice, hydrography, mixed layer depths (MLDs), and ocean currents, through comparison with a control simulation in which the equivalent iceberg mass flux is applied as coastal runoff, a common forcing in ocean models. In the Southern Hemisphere (SH), drift and melting of icebergs are in balance after around 5 years, whereas the equilibration timescale for the Northern Hemisphere (NH) is 15-20 years. Iceberg drift patterns, and Southern Ocean iceberg mass, compare favourably with available observations. Freshwater forcing due to iceberg melting is most pronounced very locally, in the coastal zone around much of Antarctica, where it often exceeds in magnitude and opposes the negative freshwater fluxes associated with sea ice freezing. However, at most locations in the polar Southern Ocean, the annual-mean freshwater flux due to icebergs, if present, is typically an order of magnitude smaller than the contribution of sea ice melting and precipitation. A notable exception is the southwest Atlantic sector of the Southern Ocean, where iceberg melting reaches around 50% of net precipitation over a large area. Including icebergs in place of coastal runoff, sea ice concentration and thickness are notably decreased at most locations around Antarctica, by up to similar to 20% in the eastern Weddell Sea, with more limited increases, of up to similar to 10% in the Bellingshausen Sea. Antarctic sea ice mass decreases by 2.9 %, overall. As a consequence of changes in net freshwater forcing and sea ice, salinity and temperature distributions are also substantially altered. Surface salinity increases by similar to 0.1 psu around much of Antarctica, due to suppressed coastal runoff, with extensive freshening at depth, extending to the greatest depths in the polar Southern Ocean where discernible effects on both salinity and temperature reach 2500 m in the Weddell Sea by the last pentad of the simulation. Substantial physical and dynamical responses to icebergs, throughout the global ocean, are explained by rapid propagation of density anomalies from high-to-low latitudes. Complementary to the baseline model used here, three prototype modifications to NEMO-ICB are also introduced and discussed.