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Towards a Mechanistic Understanding of One of the Rainiest Spots on Earth
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  • John F. Mejia,
  • Johanna Yepes,
  • Juan J. Heano,
  • German Poveda,
  • David J. Raymond,
  • Zeljka Fuchs-Stone,
  • Manuel D. Zuluaga
John F. Mejia
Desert Research Institute

Corresponding Author:[email protected]

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Johanna Yepes
Desert Research Institute, Institución Universitaria Colegio Mayor de Antioquia, Universidad Nacional de Colombia Sede Medellín,Universidad Nacional de Colombia Sede Medellín,Universidad Nacional de Colombia Sede Medellín
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Juan J. Heano
GIGA, Escuela Ambiental, Facultad de Ingeniería, Universidad de Antioquia, Medellín, Colombia
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German Poveda
Universidad Nacional de Colombia Sede Medellín
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David J. Raymond
New Mexico Tech
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Zeljka Fuchs-Stone
New Mexico Tech
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Manuel D. Zuluaga
Universidad Nacional de Colombia
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According to TRMM and 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 development of 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 show 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) land breeze favors ChocoJet deceleration offshore, enhancing the nighttime and early morning low-level convergence; (3) vertical wind shear and tilting of vertical wind shear into vorticity lines that interact with convective outflows; (4) action of mid-level gravity waves, which support the strong diurnal variability; (5) mesoscale convective vortices related to subsidence in the stratiform region in long lasting MCSs reinforcing (3); and (6) the likely role of land surface-atmosphere interactions and the rainforest over western Colombia. This study emphasizes the multi-scale environmental processes 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 (OTREC; August-September, 2019) which support the outlined mechanisms.
16 Mar 2021Published in Journal of Geophysical Research: Atmospheres volume 126 issue 5. 10.1029/2020JD033415