Lecture 22: Southern Ocean closing the global overturning circulation Flashcards
(9 cards)
What is “water mass transformation” in the Southern Ocean?
It’s the change of water from one class (defined by potential density and temperature) to another, driven by heat and freshwater fluxes.
What is the Mixed Layer Depth (MLD)?
The depth of the surface ocean that directly interacts with the atmosphere.
How does MLD in the Southern Hemisphere compare to the Northern Hemisphere?
It is generally deeper in the Southern Hemisphere, especially due to the Antarctic Circumpolar Current (ACC).
What dominates buoyancy fluxes in the sea-ice sector?
Freshwater fluxes dominate buoyancy fluxes, especially from sea ice formation/melt and precipitation.
What processes drive upwelling and downwelling in the Southern Ocean?
Ekman transport, wind-driven convergence/divergence, and geostrophic currents.
What is the effect of winter cooling on the mixed layer?
Surface water cools and convects downward, deepening the mixed layer and increasing its density.
What drives seasonal buoyancy changes in the Southern Ocean?
Winter:
buoyancy loss due to cooling and ice formation;
Summer:
buoyancy gain from freshwater input and heating.
Where is the densest water in the Southern Ocean formed?
In the Ross Sea, Weddell Sea, and Prydz Bay regions.
What are some key Southern Ocean water masses and their full names?
AABW – Antarctic Bottom Water
CDW – Circumpolar Deep Water
MCDW – Modified Circumpolar Deep Water
AAIW – Antarctic Intermediate Water
SAMW – Subantarctic Mode Water
AASW – Antarctic Surface Water
DSW – Dense Shelf Water
HSSW – High Salinity Shelf Water
