Hold onto your hats folks, we are entering the South Subtropical Convergence Zone!
From the deep blue waters between 10 and 35° S, one crosses over the boundary between the South Atlantic Gyre and the Antarctic Circumpolar Current into green waters. It can be a bumpy ride sailing through the roaring forties and then into the ferocious fifties. We have experienced 40 knot winds and a sea state of force 8!
AVHRR sea-surface temperature median composite on 18–24 October 2017. The South Subtropical Convergence Zone is demarked from the Southern Gyre by the green band of 15C water. (Satellite imagery provided by SilviaPardo, National Earth Observation Data Archive and Analysis Service)
The voyage turns into a roller coaster ride, on which you better make sure that your scientific equipment is properly secured, otherwise it can end up in pieces on the deck.
The Subtropical Convergence is the frontal zone that separates the sub-Antarctic waters of the West Wind Drift from the subtropical waters to the north.
In this region there is a convergence, or ‘piling’ up of water, from the current in the surface mixed layer that becomes subducted into the oceanic thermocline. These dynamic processes combine to form strong ...