EGU21-13346
https://doi.org/10.5194/egusphere-egu21-13346
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Anomalous transport of heat and salt by a long-lived anticyclonic eddy  in the northeast tropical Pacific Ocean

Kaveh Purkiani1, Maren Walter1, Matthias Haeckel2, Katja Schmidt3, André Paul1, Annemiek Vink3, and Michael Schulz1
Kaveh Purkiani et al.
  • 1Center for Marine Environmental Science (MARUM), Bremen, Germany (kpurkiani@marum.de)
  • 2GEOMAR Helmholtz Center for Ocean Research Kiel, Kiel, Germany
  • 3Federal Institute for Geosciences and Natural Resources (BGR), Hannover, Germany

During RV Sonne expedition SO268 to the northeast tropical Pacific Ocean between March and May 2019, the impact of a mesoscale eddy on the seawater properties was investigated by conducting a multiple of observations. A subsequent analysis of an altimeter data revealed the formation of an anticyclonic mesoscale eddy in the Tehuantepec gulf between 15 and 20 June 2018 with a mean radius of 185 km and an average speed of 13 cm/s. This extremely long-lived eddy carried sea-water characteristics from near coastal Mexican waters westward far into the open ocean. The water mass stayed largely isolated during the 11 months of travel time due to high rotational speed.

The eddy exhibited a conical-shape vertical structure with concurrent deepening of the main thermocline. The water in the eddy core showed an extreme positive temperature anomaly of 8C, a negative salinity anomaly of -0.5 psu and a positive dissolved oxygen concentration anomaly of +160 μmol/kg centered at 80 m depth. The sub-surface impact of the eddy is clearly evident in the temperature and salinity profiles at a depth of 1500 m. For dissolved oxygen the eddy-induced anomaly reached even deeper to the seafloor.

This study provides new insights to the offshore transport of heat and salt driven by the long-lived anticyclonic eddy in the northeast tropical Pacific Ocean. Considering the water column trapped within the eddy, a positive heat transport anomaly of 1-3 ×1011 W and a negative salt transport anomaly of -8×103 kg/s were estimated. However, due to the rare occurrence of long-lived anticyclone eddies in this region, they likely do not play a significant role in affecting the heat and salt balance of the northeastern tropical Pacific Ocean.

How to cite: Purkiani, K., Walter, M., Haeckel, M., Schmidt, K., Paul, A., Vink, A., and Schulz, M.: Anomalous transport of heat and salt by a long-lived anticyclonic eddy  in the northeast tropical Pacific Ocean, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-13346, https://doi.org/10.5194/egusphere-egu21-13346, 2021.

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