Re-emergence of North Atlantic subsurface ocean temperature anomalies in a seasonal forecast system
Re-emergence of North Atlantic subsurface ocean temperature anomalies in a seasonal forecast system
复制标题
季节性预报系统中北大西洋次表层海洋温度异常的重新出现
作者：
J. P. Grist;B. Sinha;H. Hewitt;A. Duchez;C. MacLachlan;P. Hyder;S. Josey;J. Hirschi;A. Blaker;A. New;Adam A. Scaife;C. Roberts
采用高分辨率海洋-大气耦合模式研究了北大西洋海底温度季节性再出现异常对北半球冬季气候的影响。从2007年9月1日到2008年2月28日，对一个50个单元的控制集合进行了整合，并与一个具有扰动海洋初始条件的平行集合进行了比较。扰动包括一个密度补偿的大西洋地下温度异常，对应于2010年9月观测到的地下温度异常。在两种大气水平分辨率（~ 60 km和~ 25 km）下重复实验，以确定大气对重新出现的温度异常的敏感性是否依赖于分辨率。在受扰动的系综中发现了广泛的再出现行为。虽然观察似乎表明，大多数重新出现在11月，但大多数成员的重新出现出现在冬季晚些时候。然而，当再次出现时，在它之前会有一个大气压力模式，在大西洋中纬度地区引发一股强大的冷、干空气流，并增加海洋潜热损失。作为对再次出现（负海温异常）的响应，潜热损失减少，大气对流减少，涡旋动能减少，下游低气压正异常。在季节预报系统的框架内，结果突出了再次出现所需的大气条件和可能对冬季大气环流产生重大影响的物理过程。
A high-resolution coupled ocean atmosphere model is used to study the effects of seasonal re-emergence of North Atlantic subsurface ocean temperature anomalies on northern hemisphere winter climate. A 50-member control ensemble is integrated from 1 September 2007 to 28 February 2008 and compared with a parallel ensemble with perturbed ocean initial conditions. The perturbation consists of a density-compensated subsurface Atlantic temperature anomaly corresponding to the observed subsurface temperature anomaly for September 2010. The experiment is repeated for two atmosphere horizontal resolutions (~ 60 km and ~ 25 km) in order to determine whether the sensitivity of the atmosphere to re-emerging temperature anomalies is dependent on resolution. A wide range of re-emergence behavior is found within the perturbed ensembles. While the observations seem to indicate that most of the re-emergence is occurring in November, most members of the ensemble show re-emergence occurring later in the winter. However, when re-emergence does occur it is preceded by an atmospheric pressure pattern that induces a strong flow of cold, dry air over the mid-latitude Atlantic, and enhances oceanic latent heat loss. In response to re-emergence (negative SST anomalies), there is reduced latent heat loss, less atmospheric convection, a reduction in eddy kinetic energy and positive low-level pressure anomalies downstream. Within the framework of a seasonal forecast system the results highlight the atmospheric conditions required for re-emergence to take place and the physical processes that may lead to a significant effect on the winter atmospheric circulation.
DOI：
10.5194/gmd-2016-194-supplement
发表时间：
2017
期刊：
--
影响因子：
--
作者：
D. Walters;I. Boutle;M. Brooks;T. Melvin;R. Stratton;S. Vosper;H. Wells;K. Williams;N. Wood
通讯作者：
D. Walters;I. Boutle;M. Brooks;T. Melvin;R. Stratton;S. Vosper;H. Wells;K. Williams;N. Wood
最近在北纬 26° 大西洋经向翻转环流中观察到的极端极小值的历史模拟
影响因子：
4.6
作者：
Blaker A
通讯作者：
Blaker A