S2S Prediction in GFDL SPEAR: MJO Diversity and Teleconnections
S2S Prediction in GFDL SPEAR: MJO Diversity and Teleconnections
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GFDL SPEAR 中的 S2S 预测：MJO 多样性和遥相关
DOI：
10.1175/bams-d-21-0124.1
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发表时间：
2022
影响因子：
8
通讯作者：
Huff, J. Jacob
中科院分区：
文献类型：
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作者：
Xiang, Baoqiang;Harris, Lucas;Delworth, Thomas L.;Wang, Bin;Chen, Guosen;Chen, Jan-Huey;Clark, Spencer K.;Cooke, William F.;Gao, Kun;Huff, J. Jacob
利用GFDL无缝预报和地球系统研究系统(SPAR)全球耦合模式，最近开发了一个亚季节到季节性(S2S)预报系统。根据20年后向预报结果(2000-19日)，北半球冬季(11-4月)Madden-Julian振荡(MJO)预报技巧在实时多变量(RMM)指数的异常相关系数降至0.5之前达到30天。然而，当MJO被划分为4种不同的传播模式时，快传播、慢传播和跳跃MJO模式的预测范围分别扩展到38、31和31天，而站立MJO模式的预测范围则下降到23天。MJO预测的进一步改进需要注意常备MJO，因为它与潜在的可预测性(38天)差距很大。慢传播的MJO在穿越海洋大陆(MC)时向南偏转，并与模式中的MC预报障碍相遇，而快传播的MJO在没有该预报障碍的情况下穿过MC的中心。MJO的多样性受平流层准两年振荡(QBO)的调制：静止(慢传播)MJO与QBO的显著西风(东风)位相重合，部分解释了这两个QBO位相之间的MJO预测技巧的差异。SPEAR模式除了传播外，还能预测不同类型的MJO以及离散的前兆对流异常的启动。Spear模式巧妙地预测了在北太平洋和北美观测到的与站立、跳跃和快速传播的MJO有关的明显遥相关，而不是慢速传播的MJO。这些发现突显了将MJO预测纳入气象变量业务预测的复杂性和挑战。
A subseasonal-to-seasonal (S2S) prediction system was recently developed using the GFDL Seamless System for Prediction and Earth System Research (SPEAR) global coupled model. Based on 20-yr hindcast results (2000–19), the boreal wintertime (November–April) Madden–Julian oscillation (MJO) prediction skill is revealed to reach 30 days measured before the anomaly correlation coefficient of the real-time multivariate (RMM) index drops to 0.5. However, when the MJO is partitioned into four distinct propagation patterns, the prediction range extends to 38, 31, and 31 days for the fast-propagating, slow-propagating, and jumping MJO patterns, respectively, but falls to 23 days for the standing MJO. A further improvement of MJO prediction requires attention to the standing MJO given its large gap with its potential predictability (38 days). The slow-propagating MJO detours southward when traversing the Maritime Continent (MC), and confronts the MC prediction barrier in the model, while the fast-propagating MJO moves across the central MC without this prediction barrier. The MJO diversity is modulated by stratospheric quasi-biennial oscillation (QBO): the standing (slow-propagating) MJO coincides with significant westerly (easterly) phases of QBO, partially explaining the contrasting MJO prediction skill between these two QBO phases. The SPEAR model shows its capability, beyond the propagation, in predicting their initiation for different types of MJO along with discrete precursory convection anomalies. The SPEAR model skillfully predicts the observed distinct teleconnections over the North Pacific and North America related to the standing, jumping, and fast-propagating MJO, but not the slow-propagating MJO. These findings highlight the complexities and challenges of incorporating MJO prediction into the operational prediction of meteorological variables.