Atlantic equatorial deep jets in Argo float data.

Bastin, Swantje , Claus, Martin , Brandt, Peter and Greatbatch, Richard John (2022) Atlantic equatorial deep jets in Argo float data. Open Access Journal of Physical Oceanography, 52 (6). pp. 1315-1332. DOI 10.1175/JPO-D-21-0140.1.

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Equatorial deep jets (EDJ) are zonal currents along the equator in all three ocean basins that alternate in direction with depth and time. In the Atlantic below the thermocline, they are the dominant variability on interannual timescales. Observations of equatorial deep jets are available but scarce, given the EDJs’ location at depth, their small vertical scale and their long periodicity of several years. In the last few years, Argo floats have added a significant amount of measurements at intermediate depth. In this study we therefore revise estimates of the EDJ scales based on Argo float data. Mostly, we use velocity data at 1000 m depth calculated from float displacement, which yield robust estimates of the Atlantic EDJ period (4.6 years), amplitude distribution, phase distribution, zonal wavelength (146.7°), and meridional structure. We also show that the equatorial amplitude of the EDJs’ first meridional mode Rossby wave component (9.8 cm s −1 ) is larger than that of their Kelvin wave component (2.8 cm s −1 ). Additionally, we present a new estimation of the EDJs’ vertical structure throughout the Atlantic basin, based on an equatorial geostrophic velocity reconstruction from hydrographic Argo float measurements from depths between 400 and 2000 m. Our new estimates from Argo float data provide the first basin-wide assessment of the Atlantic EDJ scales, as well as having smaller uncertainties than estimates from earlier studies.

Document Type: Article
Funder compliance: info:eu-repo/grantAgreement/EC/H2020/817578; BMBF: 03F0443B
Keywords: Equatorial Deep Jets, ARGO
Research affiliation: OceanRep > SFB 754
OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-OD Ocean Dynamics
OceanRep > GEOMAR > FB1 Ocean Circulation and Climate Dynamics > FB1-PO Physical Oceanography
Main POF Topic: PT2: Ocean and Cryosphere
Refereed: Yes
Open Access Journal?: No
Publisher: AMS (American Meteorological Society)
Related URLs:
Projects: PIRATA, TRIATLAS, SFB754, ARGO Program, BMBF Nordatlantik, RACE
Date Deposited: 28 Apr 2022 09:33
Last Modified: 08 Feb 2023 09:38

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