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What does mid-ocean ridge block and where?
AABW near equator
How do subtropical gyres affect deep ocean?
Location of gyre results in permanent, deeper thermacline.
What are surface flows dominated by? What direction do they travel in? What directions is deep ocean circulation?
Surface flows are dominated by subtropical gyres: move from east to west.
Deep ocean circulations move North and South.
Where is North Atlantic Deep Water formed? (2)
Where does it go? What's special about it?* How is it distinguished from AABW?
Formed in Norwegian/Greenland Sea
Moves South and is most ubiquitous. Most voluminous deep water mass in the world. NADW is distinguished from AABW bc of NADW's has higher salinity & temp.
Which deep water mass is oxygen rich? As it moves, what happens to its oxygen content?
Who has higher O2 conc in deep water: pacific or atlantic. Why?
NADW. As it moves south, loses O2 content.
Atlantic has higher O2 content bc it is more mobile, Pacific deep water is older.
Why are zones of divergence frequently highly productive?
upwelling of nutrient rich water --> phytoplankton blooms
How are changes in atmospheric and oceanic circulation linked along equatorial Pacific?
El Nino - when trade winds decrase, there is a decrease in pressure gradient. Thermocline relaxes and upwells warm water --> nutrient depleted.
Which currents are often associated with coastal upwelling? (4)
California, Peru, Canary, Benguala currents
In what pressure system and what type of wind does upwelling occur? What happens to the thermocline, surface layer and pycnocline?
Low pressure --> cyclonic wind --> upwelling.
Higher thermocline, thinner surface layer, shallower pycnocline.
If you curl fingers in direction of winds and you point out, is it upwelling or downwelling?
POINT OUT = UPWELLING.
In what pressure system and what type of wind does downwelling occur? What happens to the thermocline, surface layer and pycnocline?
Where especially does this occur?
High pressure system --> anticyclonic wind --> downwelling --> lowe rthermocline.
Thicker surface layer, deeper pycnocline.
Areas where surface water density is increased by cooling/evaporation.
Where are principle areas of open ocean divergences and convergences? (2,1)
Divergences: 1. Band that parallels equator between N and S equatorial currents 2. Band around antarctica bt Antarctic circumpolar current and eastward coastal flow around continent
Convergences: 1. center of each subtropical suface current gyres
What two things lead to Ekman transport offshore?
Anticyclonic winds around atmospheric high pressure systems