On the influence of sea‐ice inhomogeneities onto roll convection in cold‐air outbreaks
On the influence of sea‐ice inhomogeneities onto roll convection in cold‐air outbreaks
复制标题
冷空气爆发时海冰不均匀性对滚流对流的影响
DOI：
10.1029/2008gl035845
复制
发表时间：
2008
影响因子：
5.2
通讯作者：
S. Raasch
中科院分区：
文献类型：
--
作者：
M. Gryschka;C. Drüe;D. Etling;S. Raasch
在本研究中，我们使用大涡模拟（LES）来模拟强冷空气爆发（CAO）期间对流大气边界层（CBL）内的滚动对流。以往的LES大多不能很好地再现滚转对流的清晰信号，特别是在CBL地表加热强、垂直风切变弱的情况下。然而，在自然界中，这种现象是非常强大的，在几乎任何CAO的卫星图像中都可以观察到翻滚对流的云街。以前的LES研究假设海冰是均匀的，与目前的研究不同，在强烈的地表加热下，只有在边缘冰区引入海冰不均匀性时，才会出现明显的滚动信号。对于较弱的表面加热，卷也没有海冰的不均匀性。研究结果表明，在强地表加热和弱垂直风切变的情况下，地表不均匀性增加了滚转形成的机会。
In this study we use large‐eddy simulations (LES) to model roll convection within the convective atmospheric boundary‐layer (CBL) during strong cold‐air outbreaks (CAO). Previous LES were mostly unsuccessful in reproducing clear signals of roll convection, especially in case of strong surface heating and weak vertical wind shear in the CBL. In nature however, this phenomenon is very robust and roll convection can be observed as cloud streets in satellite pictures of almost any CAO. Previous LES studies assumed homogeneous sea‐ice, unlike the current study, where under strong surface heating clear signals of rolls appear only when introducing sea‐ice inhomogeneities in the marginal ice zone. For weaker surface heating, rolls also appear without sea‐ice inhomogeneities. The results of this study suggest that in case of strong surface heating and weak vertical wind shear surface inhomogeneities increase the chance of roll formation.