EGU21-9777
https://doi.org/10.5194/egusphere-egu21-9777
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

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

Rebecca Hummels1, Marcus Dengler1, Willi Rath1, Gregory R. Foltz2, Florian Schütte1, Tim Fischer1, and Peter Brandt1,3
Rebecca Hummels et al.
  • 1GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany (rhummels@geomar.de)
  • 2NOAA/AOML, Miami, FL, USA
  • 3Kiel University, Kiel, Germany

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 Wm−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.

How to cite: Hummels, R., Dengler, M., Rath, W., Foltz, G. R., Schütte, F., Fischer, T., and Brandt, P.: Surface cooling caused by rare but intense near-inertial wave induced mixing in the tropical Atlantic, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-9777, https://doi.org/10.5194/egusphere-egu21-9777, 2021.

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