Observations and Mechanisms for the Formation of Deep Equatorial and Tropical Circulation

• Published in: Earth and space science (Hoboken, N.J.) N.J.), 2019-03, Vol.6 (3), p.370-386
• Main Authors: Ménesguen, Claire, Delpech, Audrey, Marin, Frédéric, Cravatte, Sophie, Schopp, Richard, Morel, Yves
• Format: Article
• Language: English
• Subjects: Atmospheric and Oceanic Physics; deep equatorial circulation; deep tropical circulation; Energy resources; Energy sources; Jets; Ocean currents; Physics; Theory; Velocity; zonal jets
• ISSN: 2333-5084; 2333-5084
• DOI: 10.1029/2018EA000438

The Intermediate and Deep Equatorial and Tropical Circulations (DEC and DTC) consist of a complex system of zonal jets. This paper attempts at unifying existing observations and theories to present our current understanding of this jets system. Recent in situ observations suggesting a continuity between DEC and DTC are confronted against the various generation mechanisms that have been proposed in the literature. The key notion to differentiate these previous studies lies in the so‐called “cascade of mechanisms,” that is, the energy pathway and equilibration processes chain that lead to the jets from their initial energy source. Many studies see the deep equatorial intraseasonal variability as the initial energy source, highlighting its key role in energizing the DEC and DTC. However, critical gaps remain in this cascade of mechanisms and limit substantially our ability to represent the jets in Ocean Global Circulation Models. This paper aims at identifying such gaps and propose future research directions. Key Points Observation of deep equatorial and tropical circulations: a complex system of zonal jets Review of theories explaining the generation mechanisms of the equatorial and tropical jets Remaining gaps and future challenges in our global understanding of deep equatorial and tropical circulations