The Madden‐Julian Oscillation (MJO) is the dominant mode of air‐sea interaction over intraseasonal timescales. The effects of the MJO are well understood, but the initiation of the MJO remains less conclusive, particularly under El Niño Southern Oscillation (ENSO) conditions. Primary MJO events are those not immediately preceded by existing MJO activity of sufficient strength. As they are rare by definition, primary MJOs remain difficult to study, especially so when observations of events are scarce and of low spatiotemporal resolution. The advent of satellites allows for more expansive observations to be made more frequently than in situ methods, thus improving the observational capabilities of pre‐primary MJO conditions in the ocean and atmosphere. We examined oceanic and atmospheric intraseasonal signals preceding two primary MJO events during contrasting ENSO events in an attempt to bridge the connection between oceanic and atmospheric observations as potentially coupled trigger mechanisms. Satellite observations and model simulations of the central and western Indian Ocean show that intraseasonal peaks in absolute dynamic topography (ADT) and sea surface temperature (SST) upward of 1 to 2 weeks prior to the observed outgoing longwave radiation (OLR) minimum. Surface ocean warming moistens the near surface through anomalous surface fluxes, which destabilizes the lower atmosphere to deep convection. Low‐level moisture flux convergence (MFC) moistens the lower atmosphere prior to convective initiation, thus forcing an increase of total column moist static energy (MSE). Coupled midtropospheric cooling is observed that further destabilizes the atmosphere. Zonal shifts in contributing initiating parameters are observed during ENSO phases.

中文翻译：

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ENSO各阶段马丹-朱利安一次涛动事件的海洋和大气耦合预分析

Madden-Julian振荡（MJO）是季节内时间尺度上海-气相互作用的主要模式。MJO的作用已广为人知，但MJO的启动仍然没有定论，特别是在厄尔尼诺南方涛动（ENSO）条件下。主要的MJO事件是那些没有足够强度的现有MJO活动立即发生的事件。由于从定义上讲它们很少见，因此初级MJO仍然很难研究，尤其是在事件观测稀少且时空分辨率较低的情况下。卫星的出现允许比原位方法更频繁地进行更广泛的观测，从而提高了海洋和大气中原始MJO条件的观测能力。我们在对比ENSO事件期间检查了两个主要MJO事件之前的海洋和大气季节内信号，以试图将海洋和大气观测之间的联系作为潜在的耦合触发机制进行桥接。卫星观测和印度洋中部和西部的模型模拟表明，绝对动态地形（ADT）和海面温度（SST）的季节内峰值在观测到的最低长波辐射（OLR）最小值之前的1至2周内向上。地表海洋变暖通过异常的表面通量使近地表湿润，这使低层大气稳定至深对流。在对流引发之前，低水平的湿气通量收敛（MFC）会润湿较低的大气层，从而迫使总色谱柱湿静能量（MSE）增大。观察到对流层中冷耦合，这进一步破坏了大气的稳定性。在ENSO阶段可以观察到贡献的启动参数的区域变化。