Surface cooling caused by rare but intense near-inertial wave induced mixing in the tropical Atlantic

Abstract The direct response of the tropical mixed layer to near-inertial waves (NIWs) has only rarely been observed. Here, we present upper-ocean turbulence data that provide evidence for a strongly elevated vertical diffusive heat flux across the base of the mixed layer in the presence of a NIW, t...

Full description

Bibliographic Details
Published in:Nature Communications
Main Authors: Hummels, Rebecca, Dengler, Marcus, Rath, Willi, Foltz, Gregory R., Schütte, Florian, Fischer, Tim, Brandt, Peter
Other Authors: GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel
Format: Article in Journal/Newspaper
Language:English
Published: Springer Science and Business Media LLC 2020
Subjects:
General Physics and Astronomy
General Biochemistry, Genetics and Molecular Biology
General Chemistry
North Atlantic
Online Access:http://dx.doi.org/10.1038/s41467-020-17601-x
http://www.nature.com/articles/s41467-020-17601-x.pdf
http://www.nature.com/articles/s41467-020-17601-x
Description
Summary:Abstract The direct response of the tropical mixed layer to near-inertial waves (NIWs) has only rarely been observed. Here, we present upper-ocean turbulence data that provide evidence for a strongly elevated vertical diffusive heat flux across the base of the mixed layer in the presence of a NIW, thereby cooling the mixed layer at a rate of 244 W m −2 over the 20 h of continuous measurements. We investigate the seasonal cycle of strong NIW events and find that despite their local intermittent nature, they occur preferentially during boreal summer, presumably associated with the passage of atmospheric African Easterly Waves. We illustrate the impact of these rare but intense NIW induced mixing events on the mixed layer heat balance, highlight their contribution to the seasonal evolution of sea surface temperature, and discuss their potential impact on biological productivity in the tropical North Atlantic.

Similar Items