GEOMAR Helmholtz-Zentrum für Ozeanforschung Kiel
Wischhofstr. 1-3
24148 Kiel
Tel.: 0431 600-0
Fax: 0431 600-2805
E-mail: info(at)geomar.de
21.09.2020: Online Ocean Circulation and Climate Dynamics Colloquium
Dr. Rebecca Hummels & Dr. Willi Rath, Physical Oceanography, Ocean Circulation and Climate Dynamics, GEOMAR: "Surface cooling caused by rare but intense near-inertial wave induced mixing in the tropical Atlantic”
online 11am
Webex meeting room. Link will follow.
The direct response of the tropical mixed layer to near-inertial waves (NIWs) has only rarely been observed. In the talk, 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.
