Ocean Circulation (2) - Eddies Flashcards
5 Characteristics of Eddies
- 5-7 Degrees C change in sea surface temperature
- Warm eddies are less common (1:2 ratio)
- 80km diameter
- Angular velocity of 150cm/s at the surface and 32cm/s at 700m
- An inverted cone shape
What is the difference between a divergent and a convergent eddy?
Divergent are cold, convergent are warm
What are 5 key roles of eddies?
- Salt transfer
- Heat transfer
- Nutrient transfer
- Energy transfer
- Water volume transfer
Where do eddies form?
On density boundaries
7 Points about Equatorial Eddies
- Found July to March
- Translate North at 10 cm/s
- Decay on underwater ridges near Barbados
- Could be responsible for water exchange between hemispheres
- Warm core, convergent eddies
- Depths vary from 500-1000m
- Diameters are ~250km
Give an example of a Meddie
The Mediterranean Outflow into the Atlantic
8 Points about the structure of Meddies
- 800m thick lens
- 100km diameter
- Saline water
- Angular Velocity of 30cm/s
- Rotation period of 5 days
- Long lived features
- Decay on the deep ocean
- Small compared to depressions
What are tidal eddies associated with?
Topography
How big are tidal eddies?
Very small. Diameters of 0.5km
Name 3 places were tidal eddies are common
- Portland Bill
- Isle of Wight
- Nell’s Point, Barry Island
Describe meddies
High density warm saline water sinks to 1000m in the North Atlantic, it recurves North past Cape St. Vincent, puts shear of the water and imparts angular momentum and vorticity to the water. In the processes topographical turning helps to form eddies (meddles). This gives a lens of warm saline water at depth
Why do we model eddies?
To look at oceanic eddies, severe storms, pollution and for checking ideas and physics (how much impact eddies have)
