Cloud‐permitting scale (3 km) simulations are made to investigate the diurnal cycle of precipitation (DCP) over the Indo‐Pacific Maritime Continent under the modulation of the Madden‐Julian Oscillation (MJO), focusing on January–February 2018 during the Years of the Maritime Continent (YMC). Comparisons with satellite precipitation and global reanalysis products show that the simulations reasonably capture main features of diurnal wind and precipitation. The MJO modulates the amplitude, timing, and propagation of the DCP through affecting both large‐scale and local circulation and convection. Under local suppressed conditions, much strengthened sea/valley breezes are generally responsible for the enhanced and earlier‐triggered (2‐ to 3‐hr lead) DCP over land. Meanwhile, stronger cooling induced by enhanced stratiform rainfall excites well‐developed gravity waves spreading outward and upward, accompanied by continuous decreases in low‐level temperature and amplified land breezes, which cause stronger and further offshore‐propagating DCP. The opposite is true under local active conditions. Modulated by the passing of MJO, the enhanced DCP also displays a systematic shift from the west to the east coasts of large islands, forming a unique dipolar structure in the anomalous island DCP. The DCP exhibits island‐dependent characteristics: With topographical elevation, the triggering mechanism of island convection transforms from later penetrating sea breeze fronts over mountain foothills to early‐excited valley winds over mountain tops. Steep topography also supports stronger intraseasonal variations of the DCP, which can be well explained by regional variations in land‐sea/mountain‐valley breezes, terrain lifting, and ambient wind‐induced advective and vertical wind shear effects.

中文翻译：

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MJO调制下海域降水的昼夜周期：云许可尺度模拟的视角

在Madden-Julian涛动（MJO）的调制下，进行了云许可规模（3 km）的模拟以调查印度太平洋海陆上的降水的日循环（DCP），重点是这些年的2018年1月至2月海陆（YMC）。与卫星降水和全球再分析产品的比较表明，模拟合理地捕获了日风和降水的主要特征。MJO通过影响大规模和局部环流和对流来调制DCP的幅度，时间和传播。在当地受到压制的条件下，大幅度加强的海/谷风通常是导致陆地上DCP增强和触发时间提前（2-3小时的领先）的原因。与此同时，层状降雨增加引起的更强的冷却作用激发了发达的重力波向外和向上传播，伴随着低空温度的持续下降和陆风的吹拂，这导致了更强的和进一步在海上传播的DCP。在局部活动条件下情况相反。通过MJO的传递，增强的DCP还显示出大岛从西向东的系统转移，在异常岛DCP中形成了独特的偶极结构。DCP表现出与岛屿相关的特征：随着地形的高程，岛屿对流的触发机制从山麓上的较晚的穿透海风锋面转变为山顶上的较早的山谷风。陡峭的地形还支持DCP的更强的季节内变化，