The response to MJO‐like forcing in a nonlinear shallow‐water model
The response to MJO‐like forcing in a nonlinear shallow‐water model
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DOI：
10.1002/2013gl057683
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发表时间：
2014-02
影响因子：
5.2
通讯作者：
Ming Bao;D. Hartmann
中科院分区：
文献类型：
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作者：
Ming Bao;D. Hartmann
本文研究了一个非线性浅水模式对类Madden-Julian振荡(MJO)热力强迫的响应，该模式包括单极热源东移，环流周期为48天，偶极加热，纬向波周期为48天，纬向波数2限制在MJO活动区。将位于太平洋的急流比作纬向均匀的北半球基本气流。结果表明，当类MJO热强迫通过海洋大陆时，下游的Rossby波响应在太平洋急流出口区表现出增强的准定常异常，这与Adams和Wallace(2014)的观测分析相一致。本文提出的动力机制可以用来解释季节内MJO-太平洋-北美型连贯性和其他温带内季节内事件。
This study examines the response to Madden‐Julian Oscillation (MJO)‐like heat forcing in a nonlinear shallow‐water model, including monopolar heating source traveling eastward with an around the world period of 48 days and dipolar heating with zonal wave period of 48 days, with zonal wave number 2 confined in longitude to the MJO active regions. A jet localized in the Pacific is compared to a zonally uniform boreal basic flow. The results show that the Rossby wave response downstream exhibits intensified quasi‐stationary anomalies in the Pacific jet exit region when the MJO‐like heat forcing passes the Maritime Continent, in accord with the observational analysis by Adames and Wallace (2014). The dynamical mechanism suggested in this study can be used to interpret the intraseasonal MJO‐Pacific North American pattern coherence and other extratropical intraseasonal events.