A local-to-large scale view of Maritime Continent rainfall: control by ENSO, MJO and equatorial waves
A local-to-large scale view of Maritime Continent rainfall: control by ENSO, MJO and equatorial waves
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DOI：
10.1175/jcli-d-21-0263.1
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发表时间：
2021-08
影响因子：
4.9
通讯作者：
Simon C. Peatman;J. Schwendike;C. Birch;J. Marsham;A. Matthews;Gui‐Ying Yang
中科院分区：
文献类型：
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作者：
Simon C. Peatman;J. Schwendike;C. Birch;J. Marsham;A. Matthews;Gui‐Ying Yang
海洋大陆（MC）日循环的典型观点是下午和晚上发生在陆地上的深对流，倾向于在夜间传播到近海。然而，有相当大的一天到一天的对流变化，离岸传播的机制还没有很好地理解。我们测试的假设，大规模的驱动程序，如ENSO，MJO和赤道波，通过修改当地的流通，可以修改的方向或强度的传播，或防止深对流触发摆在首位。以本地到大尺度的方法，我们使用原位观测，卫星数据和再分析五个MC沿海地区，并表明，周日对流的发生及其离岸传播是紧密联系在一起的沿海风制度，我们定义使用k-均值聚类算法。强烈的陆上盛行风与降水的日周期受到抑制有关;而海上盛行风与活跃的日周期、对流的海上传播和极端降雨的更大风险有关。ENSO，MJO，赤道Rossby波和向西混合Rossby重力波有不同程度的控制沿海风况的发生，因此对降水，取决于MC的海岸线的问题。大规模的驱动程序与干燥和潮湿的制度总结了每个位置作为参考预报员。
The canonical view of the Maritime Continent (MC) diurnal cycle is deep convection occurring over land during the afternoon and evening, tending to propagate offshore overnight. However, there is considerable day-to-day variability in the convection, and the mechanism of the offshore propagation is not well understood. We test the hypothesis that large-scale drivers such as ENSO, the MJO and equatorial waves, through their modification of the local circulation, can modify the direction or strength of the propagation, or prevent the deep convection from triggering in the first place. Taking a local-to-large scale approach we use in situ observations, satellite data and reanalyses for five MC coastal regions, and show that the occurrence of the diurnal convection and its offshore propagation is closely tied to coastal wind regimes we define using the k-means cluster algorithm. Strong prevailing onshore winds are associated with a suppressed diurnal cycle of precipitation; while prevailing offshore winds are associated with an active diurnal cycle, offshore propagation of convection and a greater risk of extreme rainfall. ENSO, the MJO, equatorial Rossby waves and westward mixed Rossby-gravity waves have varying levels of control over which coastal wind regime occurs, and therefore on precipitation, depending on the MC coastline in question. The large-scale drivers associated with dry and wet regimes are summarised for each location as a reference for forecasters.