热带经圈环流的调制：Madden-Julian振荡的作用
Modulation of the tropical meridional circulation by the Madden-Julian Oscillation
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中文总结 AI 辅助
本研究揭示Madden-Julian振荡（MJO）可系统性调制哈德利环流，识别出与活跃MJO相关的半球不对称环流异常，发现哈德利环流滞后MJO 4-15天，明确了热带季节内振荡与经圈环流的新关联路径。
中文摘要 AI 辅助
哈德利环流是地球主导的热带翻转环流，调控大气能量输送、热带降雨及副热带干旱。尽管其在季节至年代际气候变化时间尺度上的变异性已被广泛研究，但其次季节尺度的行为仍知之甚少。本研究表明，热带季节内变异性的主导模态Madden-Julian振荡（MJO）会系统性调制哈德利环流，并影响全球水文气候变异性。利用再分析数据和动力学诊断，我们识别出与活跃MJO事件相关的、稳健的半球不对称哈德利环流异常，其振幅可与哈德利环流的气候态季节内变异性相比。分解动力学成分后发现，该响应主要由与 moist 对流相关的潜热维持，而翻转强度由半球间湿度梯度驱动。超前-滞后分析进一步显示，哈德利环流滞后MJO 4-15天，表明MJO对流可在次季节时间尺度上驱动翻转调整。这种耦合的MJO-哈德利环流态揭示了一条此前被忽视的路径，将热带季节内振荡、经圈环流与水文循环关联起来。
英文摘要
The Hadley circulation is Earth's dominant tropical overturning circulation, regulating atmospheric energy transport, tropical rainfall, and subtropical aridity. Although its variability has been extensively studied on seasonal to decadal climate-change timescales, its subseasonal behaviour remains poorly understood. Here we show that the Madden-Julian Oscillation (MJO), the leading mode of tropical intraseasonal variability, systematically modulates the Hadley circulation and influences global hydroclimate variability. Using reanalysis data and dynamical diagnostics, we identify a robust hemispherically asymmetric Hadley circulation anomaly associated with active MJO events, with amplitudes comparable to the climatological intraseasonal variability of the Hadley circulation. Breaking down the dynamical components reveals that the response is primarily maintained by latent heating associated with moist convection, while the overturning strength is driven by interhemispheric moisture gradients. Lead-lag analyses further show that the Hadley circulation lags the MJO by 4-15 days, indicating that MJO convection may drive overturning adjustments on subseasonal timescales. This coupled MJO-Hadley circulation state reveals a previously overlooked pathway linking tropical intraseasonal oscillations, meridional circulation and the hydrological cycle.
