Variabilidad estacional de la AMOC: La Corriente de Canarias

The ocean and the atmosphere regulate the climate in the earth, since both transport heat from the equator towards higher latitudes. The Atlantic Ocean plays a significant role in this system, being the only ocean that transports heat to the north in all the latitudes. The Atlantic Meridional Overturning Circulation (AMOC), which is composed by the south- north circulation, transports 18Sv (1Sv=10E6m3/s) of water that carries more that 1.5PW (1PW=10E15W) of heat to the North Atlantic, and therefore plays a determining role in regulating the climate in Europe. Since 2004 the Rapid Array has made possible estimations of the AMOC systematically. The first analysis of these continuous estimations indicates, for the first time, that there is a strong seasonal cycle in the AMOC, with amplitude of 6.7 Sv peak to peak. The minimum northward transport is in March and maximum in is October. Most of this seasonal variability, 5.4 Sv, may be explained alone by the contribution of the eastern Atlantic component of the Rapid array. The driving mechanism of this large seasonal would be the wind stress curl in this around the Canary Islands. This proposed mechanism is against the previous paradigm that established the Ekman transport as the main contribution to the seasonal variability of the AMOC. Moreover, if the driving mechanism was the wind stress curl in the eastern Atlantic, a Rossby wave model should explain most of the seasonal variability.

In this project, we hypothesize that the seasonal cycle of the Canary Current (CC) and the Canary deep Poleward Undercurrent (CdPU) altogether explains most of the seasonal variability of the eastern component of the AMOC as measured by the RAPID array. We will also address the importance of the meridional pressure gradient between the Mediterranean Outflow Waters and the Antarctic Intermediate Waters to contribute to the seasonal behavior of the AMOC. To verify the proposed hypothesizes the approach will be mainly observational, carrying out two 12-days cruises and extending, for the duration of this project, and a long term mooring first deployed in 1997. The analysis will be complemented with the analysis of historical data in the area, altimeter data, and data from the Argo ocean Observing network. Data from publically available model simulation will be used to investigate the role of the wind forcing in the developing of the CdPU.{jcomments off}

Contact person: 
Alonso Hernández Guerra
Funding agency: 
Ministerio de Economía y Competitividad