Impact of the Madden-Julian Oscillation on extreme precipitation over the western Maritime Continent and Southeast Asia
Impact of the Madden-Julian Oscillation on extreme precipitation over the western Maritime Continent and Southeast Asia
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DOI：
10.1002/qj.4136
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发表时间：
2021-08-09
影响因子：
8.9
通讯作者：
Matthews, Adrian J.
中科院分区：
文献类型：
--
作者：
Da Silva, Nicolas A.;Matthews, Adrian J.
西海洋大陆（MC）和东南亚位于地球上最大的高降水区的中心。极端降水是影响该地区5亿多人口的主要高影响力天气事件之一。与这种极端降水相关的深对流很难预测，即使是现代高分辨率数值天气预报与显式对流。然而，更大规模的有组织的对流系统，如马登-朱利安振荡（MJO），可以巧妙地预测到3-5周的提前时间。MJO有一个众所周知的降水信号，它也可能调制极端降水。在这里，MJO的极端降水信号进行了详细的分析，使用19年的高分辨率综合多卫星反演全球降水测量（GPM IMERG）数据的西部MC和东南亚。经历极端降水的可能性增加了两个强大的因素，并减少了一半的因素，取决于位置和MJO的阶段。极端降水的这些变化的空间模式并没有描述一个平稳的向东传播，但在短距离内显示出快速变化，与群岛内陆地和海洋的复杂分布有关。在某些地方，这种MJO调制也有季节性依赖性。MJO对极端降水的影响进行了更详细的分析，在该地区的主要城市。在MC极端降水日数通常与放大的日周期。然而，虽然活跃的MJO增加极端降水日的频率，因此放大的日周期，有没有进一步放大的日周期在活跃的MJO，与极端降水日在非活跃的MJO期间。
The western Maritime Continent (MC) and Southeast Asia lie at the heart of the largest area of high precipitation on Earth. Extreme precipitation is one of the major high-impact weather events to affect the population of over 500 million in this region. The deep convection associated with this extreme precipitation is difficult to forecast, even with modern high-resolution numerical weather prediction with explicit convection. However, larger-scale organised convective systems, such as the Madden-Julian Oscillation (MJO), can be skilfully predicted to 3-5 weeks lead time. The MJO has a well-known precipitation signal, and it is likely that it also modulates extreme precipitation. Here, the extreme precipitation signal of the MJO is analysed in detail for the western MC and Southeast Asia using 19 years of high-resolution Integrated Multi-satellitE Retrievals for Global Precipitation Measurement (GPM IMERG) data. The probability of experiencing extreme precipitation increases robustly by a factor of two, and decreases by a factor of half, dependent on location and the phase of the MJO. The spatial pattern of these changes in extreme precipitation does not describe a smooth eastward propagation, but shows rapid variation over short distances, tied to the complex distribution of land and sea within the archipelago. There is also a seasonal dependence of this MJO modulation in some locations. A more detailed analysis of the effect of the MJO on extreme precipitation is presented for the major cities in the region. Extreme precipitation days over the MC are generally linked with an amplification of the diurnal cycle. However, although an active MJO increases the frequency of extreme precipitation days and therefore an amplified diurnal cycle, there was no further amplification of the diurnal cycle in the active MJO, compared with extreme precipitation days during non-active MJO periods.