Chapter 7 Flashcards
_______ are a result of global prevailing wind patterns known as the ______ and _______.
Surface Currents;Trade Winds;Westerlies
Surface currents form above the _____ and create large-scale circular-moving loops of water known as _______
Pycnocline;Subtropical Gyres
Gyres are made up of ________ (N,S,E,W) and ______ (E and W)
boundary currents;equatorial currents
Surface currents are influenced by:
- the _______
- the _______
- the _______ and _______ which describe the speed and direction of water at different depths
- Ekman Transport produces a _______ (or “hill” ) of water within gyres
- ________ form as water flows down the “hill” under the influence of _____ and the ______
- the ________ of the “hill” results in narrow, deep, and strong currents on the western boundaries of ocean basins
- shapes of continents
- Coriolis effect
- Ekman Spiral;Ekman Transport
- Subtropical Convergence
- “Geostrophic Currents”; gravity; Coriolis effect
- Western Intensification
The ________ flows at 2.5 m/sec (or ~5
mph)
Gulf Stream Current
_______ are used to measure surface currents
Drift Meters
Choose one: (Surface currents/Deep Currents) A. Direct Methods 1. Floating device tracked through time 2. Fixed current meter
B. Indirect Methods
- Pressure gradients
- Radar altimeters
- Doppler flow meter
Surface currents
Choose one: (Surface currents/ Deep Currents) A. Direct Methods 1. Floating devices tracked through time 2. Chemical Tracers 3. Tritium 4. Chlorofluorocarbons
B. Indirect Methods
1. Characteristic temperature and salinity conditions
Deep Currents
- Surface currents _______ away from the equator
and toward the poles - warm currents result in ______ coastal climates
- cold currents result in ______ coastal climates
- Transfer Heat
- wet/humid
- dry/arid
Offshore currents result in _____ and _______ and onshore currents result in ______
- important for ocean mixing
Upwelling; high biological activity; Downwelling
__________ occurs as Trade Winds move surface water away from the equator
Equatorial Upwelling
Deep Ocean Currents are caused by density differences in seawater below the _____ and result in _______
Pycnocline;Thermohaline Circulation
__________ is a combination of deep ocean currents and surface currents
”Conveyor-Belt Circulation”
Changes in the global deep-water circulation pattern can dramatically and abruptly change climate. Example:
- The Day After Tomorrow
1) downwelling
A) seasonal wind pattern
B) water mass found in the Sargasso Sea
C) net water movement to the left or right of the direction of the wind
D) movement of water from the bottom to the top of the water column
E) unit of current velocity
AB) water flow driven by gravity and modified by the Coriolis force
AC) movement of water from the top to the bottom of the water column
movement of water from the top to the bottom of the water column
2) Ekman transport
A) seasonal wind pattern
B) water mass found in the Sargasso Sea
C) net water movement to the left or right of the direction of the wind
D) movement of water from the bottom to the top of the water column
E) unit of current velocity
AB) water flow driven by gravity and modified by the Coriolis force
AC) movement of water from the top to the bottom of the water column
net water movement to the left or right of the direction of the wind
3) geostrophic current
A) seasonal wind pattern
B) water mass found in the Sargasso Sea
C) net water movement to the left or right of the direction of the wind
D) movement of water from the bottom to the top of the water column
E) unit of current velocity
AB) water flow driven by gravity and modified by the Coriolis force
AC) movement of water from the top to the bottom of the water column
??????water flow driven by gravity and modified by the Coriolis force
4) upwelling
A) seasonal wind pattern
B) water mass found in the Sargasso Sea
C) net water movement to the left or right of the direction of the wind
D) movement of water from the bottom to the top of the water column
E) unit of current velocity
AB) water flow driven by gravity and modified by the Coriolis force
AC) movement of water from the top to the bottom of the water column
movement of water from the bottom to the top of the water column
5) California Current
A) tropical latitudes
B) cold current, northern hemisphere, temperate
latitudes
C) northern hemisphere, temperate latitudes, warm
current
D) cold current, southern hemisphere, temperate
latitudes
E) cold current, polar latitudes, southern hemisphere
cold current, northern hemisphere, temperate
latitudes
6) Gulf Stream
A) tropical latitudes
B) cold current, northern hemisphere, temperate
latitudes
C) northern hemisphere, temperate latitudes, warm
current
D) cold current, southern hemisphere, temperate
latitudes
E) cold current, polar latitudes, southern hemisphere
northern hemisphere, temperate latitudes, warm
current
7) West Wind Drift
A) tropical latitudes
B) cold current, northern hemisphere, temperate
latitudes
C) northern hemisphere, temperate latitudes, warm
current
D) cold current, southern hemisphere, temperate
latitudes
E) cold current, polar latitudes, southern hemisphere
cold current, polar latitudes, southern hemisphere
8) Equatorial currents are driven by the \_\_\_\_\_\_\_\_. A) Coriolis force B) density C) Ekman transport D) trade winds E) westerlies
trade winds
9) The Ekman spiral is caused by ________.
A) density differences in the water column
B) the wind and gravity
C) the wind and the Coriolis effect
D) the pycnocline
E) pressure gradients
????the wind and the Coriolis effect
10) Which type of current flow moves in a circular path around a subtropical convergence, reflecting Ekman transport, gravity, and the Coriolis effect? A) Counter-current circulation B) Density-driven circulation C) Geostrophic circulation D) Langmuir circulation E) Thermohaline circulation
Geostrophic circulation
Students sometimes ask…Is the Gulf Stream rich in life?
-not rich in life but the boundaries are
-Warm water current
-low productivity and an absence of marine life
Additional info:
-Kuroshio Currents
Northern Pacific Ocean
named for absence of marine life
it means black current (clear, lifeless water)
Students sometimes ask..What is the Loop current, and how are hurricanes affected by it?
- warm ocean surface current in the Gulf of Mexico
- flows northward between Cuba and the Yucatan Peninsula
- moves north into the Gulf of Mexico
- Loops east and south before exiting to the east through Florida straits and eventually merging w/ other waters to form the Gulf Stream
- Loop Current eddies= rings that spin off from the Loop Current
Students sometimes ask..Do El Nino events occur in other ocean basins?
- Yes
- Atlantic and Indian Oceans
- Great width of the Pacific Ocean in equatorial latitudes is the main reason that El Nino events occur more strongly in the Pacific
