Large-scale controls of propagation of the Madden-Julian Oscillation
Large-scale controls of propagation of the Madden-Julian Oscillation
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DOI：
10.1038/s41612-020-00134-x
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发表时间：
2020-07-28
影响因子：
9
通讯作者：
Su, Hui
中科院分区：
文献类型：
--
作者：
Jiang, Xianan;Maloney, Eric;Su, Hui
麦登-朱利安振荡（MJO）对全球气候和极端天气有着广泛的影响，在亚季节预报中起着至关重要的作用。然而，我们最新的全球气候模式（GCM）在真实地模拟MJO方面有很大的困难。这种模式的不适用主要是由于MJO的积云组织的代表性问题。这项研究的基础上，一系列的理想化的水行星模型实验，使用一个只有大气GCM，清楚地表明，MJO传播强烈调制的大尺度背景状态，其中低对流层平均湿度梯度和纬向风是至关重要的。因此，当调整气候模式，以实现改进的MJO模拟，特别需要注意的是放在模型的大尺度平均状态，也显着影响积云参数化。这项研究表明，模型偏差代表MJO传播可能与广泛报道的双ITCZ（热带辐合带）的气候模式的问题。
With widespread influence on global climate and weather extremes, the Madden-Julian Oscillation (MJO) plays a crucial role in subseasonal prediction. Our latest global climate models (GCMs), however, have great difficulty in realistically simulating the MJO. This model inability is largely due to problems in representation of MJO's cumulus organization. This study, based on a series of idealized aqua-planet model experiments using an atmospheric-only GCM, clearly demonstrates that MJO propagation is strongly modulated by the large-scale background state in which the lower-tropospheric mean moisture gradient and zonal winds are critical. Therefore, when tuning climate models to achieve improved MJO simulations, particular attention needs to be placed on the model large-scale mean state that is also significantly affected by cumulus parameterizations. This study indicates that model biases in representing MJO propagation may be related to the widely reported double-ITCZ (intertropical convergence zone) problem in climate models.