The Impact of Finer-Resolution Air-Sea Coupling on the Intraseasonal Oscillation of the Indian Monsoon
The Impact of Finer-Resolution Air-Sea Coupling on the Intraseasonal Oscillation of the Indian Monsoon
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DOI：
10.1175/2010jcli3868.1
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发表时间：
2011-05-15
影响因子：
4.9
通讯作者：
Slingo, Julia M.
中科院分区：
文献类型：
--
作者：
Klingaman, Nicholas P.;Woolnough, Steven J.;Slingo, Julia M.
描述了一个新组装的大气海洋耦合模型，称为 HadKPP，然后用于确定亚日海气耦合和精细近地表海洋垂直分辨率对北半球夏季季节内振荡表示的影响。 HadKPP 包括与 K 剖面参数化海洋边界层模型耦合的哈德利中心大气模型。执行了四个 30 成员的集合，海洋垂直分辨率在 1 到 10 m 之间变化，耦合频率在 3 到 24 h 之间变化。 10 米、24 小时的集合显示了观测到的 30-50 天海面温度和降雨量变化的大约 60%，并且向北传播非常弱。仅增强垂直分辨率或仅增强耦合频率会产生适度的变化性改善，并且仅产生持续的季节内振荡。只有 1 米、3 小时的配置才能产生与观测结果类似的有组织的、向北传播的对流。次日表面强迫产生了与异常对流正交的更强的上层海洋温度异常，这可能影响对流之前的低层大气稳定性，从而引起传播。良好解析的海气耦合并没有改善该模型中北半球夏季季节内振荡的向东传播。必须改进耦合模型中的上层海洋垂直混合和日变率，以准确解析和模拟热带次季节变率。在 HadKPP 中，仅存在海气耦合不足以产生类似于观测结果的季节内振荡。
A newly assembled atmosphere ocean coupled model, called HadKPP, is described and then used to determine the effects of subdaily air-sea coupling and fine near-surface ocean vertical resolution on the representation of the Northern Hemisphere summer intraseasonal oscillation. HadKPP comprises the Hadley Centre atmospheric model coupled to the K-Profile Parameterization ocean boundary layer model.Four 30-member ensembles were performed that vary in ocean vertical resolution between 1 and 10 m and in coupling frequency between 3 and 24 h. The 10-m, 24-h ensemble exhibited roughly 60% of the observed 30-50-day variability in sea surface temperatures and rainfall and very weak northward propagation. Enhancing only the vertical resolution or only the coupling frequency produced modest improvements in variability and just a standing intraseasonal oscillation. Only the 1-m, 3-h configuration generated organized, northward-propagating convection similar to observations. Subdaily surface forcing produced stronger upper-ocean temperature anomalies in quadrature with anomalous convection, which likely affected lower-atmospheric stability ahead of the convection, causing propagation. Well-resolved air sea coupling did not improve the eastward propagation of the boreal summer intraseasonal oscillation in this model.Upper-ocean vertical mixing and diurnal variability in coupled models must be improved to accurately resolve and simulate tropical subseasonal variability. In HadKPP, the mere presence of air sea coupling was not sufficient to generate an intraseasonal oscillation resembling observations.