Parameterizing Turbulent Exchange over Sea Ice in Winter
Parameterizing Turbulent Exchange over Sea Ice in Winter
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DOI：
10.1175/2009jhm1102.1
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发表时间：
2010-02-01
影响因子：
3.8
通讯作者：
Fairall, Christopher W.
中科院分区：
文献类型：
--
作者：
Andreas, Edgar L.;Persson, P. Ola G.;Fairall, Christopher W.
北冰洋表面热量收支（SHEBA）实验产生了18 000 h的湍流数据，从大气表层海冰，而冰营漂流了一年的博福特环流。SHEBA期间的多个站点仪表表明只有两个海冰空气动力学季节。在“冬季”（1997年10月至1998年5月14日和1998年9月15日至1998年10月初SHEBA部署结束），冰很致密，被雪覆盖，雪很干燥，可以漂流和吹。在“夏季”（1998年5月15日至9月14日），雪融化，融化的池塘和铅出现，并覆盖了多达40%的表面与开放的水。本文发展了一种整体湍流通量的计算方法来解释冬季资料。该算法预测的表面通量的动量，显热和潜热更容易测量或建模的量。分析的一个主要结果是，风速z（0）的粗糙度长度不取决于飘雪状态下的摩擦速度u（*）（u（*）>= 0.30 m s（-1）），而是在SHEBA数据集中恒定在约2.3 x 10（-4）m。先前的分析发现，在飘雪期间，z（0）随u（*）增加，这可能是虚构的相关性，因为u（*）也出现在z（0）中。本分析通过绘制测量的z（0）与根据体通量算法计算的相应u（*）来减轻这种虚构的相关性。用来自六个不同SHEBA站点的数据创建的这些图显示，对于0.15，u（*），z（0）与体积u（*）无关。
The Surface Heat Budget of the Arctic Ocean (SHEBA) experiment produced 18 000 h of turbulence data from the atmospheric surface layer over sea ice while the ice camp drifted for a year in the Beaufort Gyre. Multiple sites instrumented during SHEBA suggest only two aerodynamic seasons over sea ice. In "winter'' (October 1997 through 14 May 1998 and 15 September 1998 through the end of the SHEBA deployment in early October 1998), the ice was compact and snow covered, and the snow was dry enough to drift and blow. In "summer'' (15 May through 14 September 1998 in this dataset), the snow melted, and melt ponds and leads appeared and covered as much as 40% of the surface with open water. This paper develops a bulk turbulent flux algorithm to explain the winter data. This algorithm predicts the surface fluxes of momentum, and sensible and latent heat from more readily measured or modeled quantities. A main result of the analysis is that the roughness length for wind speed z(0) does not depend on the friction velocity u(*) in the drifting snow regime (u(*) >= 0.30 m s(-1)) but, rather, is constant in the SHEBA dataset at about 2.3 x 10(-4) m. Previous analyses that found z(0) to increase with u(*) during drifting snow may have suffered from fictitious correlation because u(*) also appears in z(0). The present analysis mitigates this fictitious correlation by plotting measured z(0) against the corresponding u(*) computed from the bulk flux algorithm. Such plots, created with data from six different SHEBA sites, show z(0) to be independent of the bulk u(*) for 0.15, u(*)