Towards a Mechanistic Understanding of Precipitation Over the Far Eastern Tropical Pacific and Western Colombia, One of the Rainiest Spots on Earth
Towards a Mechanistic Understanding of Precipitation Over the Far Eastern Tropical Pacific and Western Colombia, One of the Rainiest Spots on Earth
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DOI：
10.1029/2020jd033415
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发表时间：
2021-02
期刊：
影响因子：
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通讯作者：
J. Mejía;Johanna Yepes;Juan J. Henao;G. Poveda;M. D. Zuluaga;D. Raymond;Ž. Fuchs‐Stone
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文献类型：
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作者：
J. Mejía;Johanna Yepes;Juan J. Henao;G. Poveda;M. D. Zuluaga;D. Raymond;Ž. Fuchs‐Stone
根据热带降雨测量任务（TRMM）和全球降水测量（GPM）卫星降水合成数据，热带太平洋远东地区和哥伦比亚西部的广阔海域是地球上雨量最多的地区之一。这项研究旨在展示一套有助于创造这样一个打破世界纪录的雨季的机械驱动因素。以往的研究表明，这次海洋和近大陆降水极大值具有强烈的清晨降水峰和高密度的中尺度对流系统。我们研究了新的和独特的观测证据，突出了动力和热力学驱动因素在有组织对流的激活和持续时间中的作用。结果表明，存在一个相当大的机制组合，包括：(1)Choco （ChocoJet）和加勒比海低空急流沿其合流区（包括巴拿马半永久低压）的动力学；(2) ChocoJet在近海减速受陆风影响，增强了夜间和清晨低空辐合；(3)符合长寿命飑线理论的风切变环境；(4)中层重力波的作用，进一步支持了强烈的日变率；(5)与层状区下沉和顶重质量通量剖面相关的中尺度对流涡。本研究强调了与地球上多雨点之一形成相关的多尺度环流和热力学机制，并展示了在热带东太平洋对流场运动组织（OTREC； 2019年8月至9月）期间收集的支持概述机制的新观测结果。
According to Tropical Rainfall Measuring Mission (TRMM) and Global Precipitation Measurement (GPM) satellite precipitation composites, a broad maritime area over the far eastern tropical Pacific and western Colombia houses one of the rainiest spots on Earth. This study aims to present a suite of mechanistic drivers that help create such a world‐record‐breaking rainy spot. Previous research has shown that this oceanic and nearly continental precipitation maximum has a strong early morning precipitation peak and a high density of mesoscale convective systems. We examined new and unique observational evidence highlighting the role of both dynamical and thermodynamical drivers in the activation and duration of organized convection. Results showed the existence of a rather large combination of mechanisms, including: (1) dynamics of the Choco (ChocoJet) and Caribbean Low‐Level Jets along their confluence zone, including the Panama semi‐permanent low; (2) ChocoJet deceleration offshore is favored by land breeze, enhancing the nighttime and early morning low‐level convergence; (3) a wind sheared environment that conforms to the long‐lived squall line theory; (4) action of mid‐level gravity waves, which further support the strong diurnal variability; and (5) mesoscale convective vortices related to subsidence in the stratiform region and top‐heavy mass flux profiles. This study emphasizes the multiscale circulation and thermodynamics mechanisms associated with the formation of one of the rainiest spots on Earth and showcases new observations gathered during the Organization of Tropical East Pacific Convection field campaign (OTREC; August–September, 2019) that support the outlined mechanisms.