Experimental Highlights of the Eddy Saturation Regime in the Southern Ocean

• Main Authors: M. Menna, Y. Cotroneo, P. Falco, P. M. Poulain, G. Budillon
• Other Authors: AA.VV., Menna, M., Cotroneo, Y., Falco, P., Poulain, P. M., Budillon, G.
• Format: Conference Object
• Language: English
• Published: WSL Institute for Snow and Avalanche Research SLF 2018
• Subjects: Pacific; Southern Ocean; sami
• Online Access: http://hdl.handle.net/11367/69110; https://www.polar2018.org/

Drifter, satellite, XBT and Argo float data are used to define the response of the Pacific Sector of the Southern Ocean (PSSO) to the large scale climatic patterns as depicted by the Southern Annular Mode Index -SAMI- and the Multivariate ENSO Index - MEI in the period 1995-2017. During this period, the SAM index is predominately positive, strengthening the westerlies, but ENSO might have played an important role producing an increase/decrease of the EKE during La Niña/El Niño events. In fact, The interplay between SAM and ENSO generates peculiar scenarios with different ocean responses where positive values of SAMI are positive/negative correlated with the EKE when MEI is negative/positive. In particular, the effects of the SAMI trend are consistent with an increase of the eddy kinetic energy (EKE) field and the ACC transport relatively constant up to the 2007. Results confirmed that the ocean state were close to the eddy saturation regime up to 2007 underlining the important role of eddies in modulating the ocean circulation response to the main atmospheric forcing. After 2007, the ACC transport shows a different pattern with three well defined maximums. Two of them are in agreement with the SAMI and MEI phases whereas there is the maximum on 2012 that is still difficult to explain.