Strengthened Causal Connections Between the MJO and the North Atlantic With Climate Warming
Strengthened Causal Connections Between the MJO and the North Atlantic With Climate Warming
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DOI：
10.1029/2020gl091168
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发表时间：
2020-10
影响因子：
5.2
通讯作者：
S. Samarasinghe;Charlotte Connolly;E. Barnes;I. Ebert‐Uphoff;Lantao Sun
中科院分区：
文献类型：
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作者：
S. Samarasinghe;Charlotte Connolly;E. Barnes;I. Ebert‐Uphoff;Lantao Sun
虽然已知Madden-Julian振荡(MJO)影响中纬度环流及其在亚季节到季节时间尺度上的可预测性，但这种联系如何随着人为变暖而变化却鲜为人知。本文研究了在社区地球系统模式2-全大气社区气候模式(CESM2-WACCM)耦合气候模式的历史模拟和SSP585模拟中，MJO和北大西洋涛动(NAO)之间因果路径的变化。采用了两种数据驱动的方法，即条带指数和图形化因果模型。这些方法共同表明，随着急流的延长，MJO对北大西洋的影响在未来会加强。此外，图形化的因果模型允许我们区分与遥相关相关的因果路径。虽然在CESM2-WACCM中平流层和对流层路径都将MJO与北大西洋连接起来，但21世纪MJO-NAO因果联系的加强完全是由于通过对流层路径的遥相关。
While the Madden‐Julian oscillation (MJO) is known to influence the midlatitude circulation and its predictability on subseasonal‐to‐seasonal timescales, little is known how this connection may change with anthropogenic warming. This study investigates changes in the causal pathways between the MJO and the North Atlantic oscillation (NAO) within historical and SSP585 simulations of the Community Earth System Model 2‐Whole Atmosphere Community Climate Model (CESM2‐WACCM) coupled climate model. Two data‐driven approaches are employed, namely, the STRIPES index and graphical causal models. These approaches collectively indicate that the MJO's influence on the North Atlantic strengthens in the future, consistent with an extended jet‐stream. In addition, the graphical causal models allow us to distinguish the causal pathways associated with the teleconnections. While both a stratospheric and tropospheric pathway connect the MJO to the North Atlantic in CESM2‐WACCM, the strengthening of the MJO‐NAO causal connection over the 21st century is shown to be due exclusively to teleconnections via the tropospheric pathway.