Chapter 6

Eastern Boundary Currents

Eastern side of ocean basins. Opposite properties of western currents. Cold, slow, shallow, and wide.

Coastal downwelling

Ekman Transport move seawater onshore.

Coastal upwelling

Ekman Transport moves seawater offshore.

Geostrophic Flow

Ekman transport piles up water within subtropical gyres. Flows downhill (gravity) and to the right (Coriolis effect).

Driving forces of wind

Gravity, Pressure Gradient force, Coriolis Force, Friction Force.

Warm currents

Gulf stream, north atlantic, norweigian currents.

Cold currents

Labrador current, Canary Current.

Local Winds

Land-Sea Breezes, Mountain-Valley Breezes, and Katabatic Winds.

Gyres

Large, circular loops of moving water.

Gulf stream

Loops. Warm surface currents, warms east coast.

Cyclone

Low pressure at center of weather system. Anti-clockwise in northern hemisphere Clockwise in southern hemisphere.

Equatorial Low-Pressure Trough

10 degrees N to 10 degrees S. A lot of energy due to constant high angle of incidence, consistent day length, and surface air heats up and rises. Intertropical Convergence Zone (ITCZ). Trade winds. Thermal

Sea-Level pressure

1013.2 mb

Normal Air pressure

1050 mb to 980 mb.

Subpolar Low-pressure Cells

Aleutian low, Icelandic Low, Polar front. In January they exist over ocean around 60 N. Cool and moist.

Deep Ocean Currents

Provide Oxygen to deep sea.

Deep water masses

Antarctic Bottom, North Atlantic, Antarctic Intermediate, Oceanic common.

Monsoonal Winds

Asian Landmass & Indian ocean drive monsoons in southeast asia. Wind and pressure patterns in upper-air circulation.

Ekman Transport

Average movement of seawater under influence of wind. NH: 90 right SH: 90 Left

Thermohaline Circulation

Below the pycocline. 90% of all ocean water. Slow velocity. Movement caused by differences in Density (temperature and salinity). Cooler seawater denser. Saltier seawater denser. Hauls large volumes of water.

Subtropical Gyres

Centered about 30 N or S.

Geostrophic Winds

Characteristic of upper troposphere. Pressure gradient force + coriolis force, flow around pressure area, remaining parallel to isobars. >500 m

Surface to deep water

Cold, oxygen rich surface water goes to deep water.

Friction effect on geostrophic winds

Decreases wind speed and Coriolis force, causes winds to move across isobars at an angle.

Wind Vane

Determines wind direction.

Friction Force

Drags on wind as it moves across surfaces; decreases with height above the surface. Without it, winds would move in paths parallel to isobars at high speed rates. Occurs below 500m

Cause/effect of coriolis force

Earth's rotation. Force increases as the speeds of the moving object increases = faster wind means greater deflection.

Driving force of ocean currents

Frictional Drag of winds.

Katabatic Winds

Gravity Drainage winds. Usually stronger than local winds under certain conditions. Elevated Plateau/highland is essential to their formation. Air cools & becomes more dense then flow in a downward slope.

Thermohaline circulation origin

High latitude surface ocean.

Anticyclone

High pressure at center of weather system. Clockwise in northern hemisphere. Anti-clockwise in southern hemisphere.

Surface Current motion&driving factor

Horizontal motion. Wind-driven. Other driving factors: distribution of continents, Gravity, friction, coriolis effect.

Barometer

Measure air pressure.

Anemometer

Measures wind speed.

Jet Streams

Most prominent movement in upper-level westerly wind flows. An irregular, concentrated band of wind occurring at several different locations that influences surface weather system. Weaken during summer & strengthen during winter.

Wind 'name'

Named for the direction from which they originate.

Atlantic Ocean Circulation

North Atlantic Subtropical Gyre, North equatorial current, gulf stream, North atlantic current, canary current, south equatorial current, south equatorial current, atlantic equatorial counter current.

Land-Sea Breezes

Occur at coastlines by different heating characteristics. Daytime : Cooler air is drawn to land. Nighttime: Cooler air is down to sea.

Polar High-Pressure Cells

Polar Easterlies and Antarctic high. Weak. Frigid and Dry. Atmospheric pressure is low, little energy to set motion. 90 degrees

Coriolis Force Affect on wind

Produces upper-air westerly winds from the subtropics to the poles. In the upper troposphere, it balances pressure gradient forces = flow parallel to isobars.

Mountain-Valley Breezes

Results when Mountain air cool rapidly at night and valley gains heat energy during the day. Daytime: warm air goes upslope Nighttime: cooler air goes downslope.

Low pressure gradient force

Rise and converge

Upper Atmospheric Circulation

Rossby Waves and Jet Steams.

Surface texture and friction

Rougher surface produce more friction

Converging Surface Seawater

Surface Seawater move towards an area. Surface seawater piles up. Seawater moves downward. DOWNWELLING low biological productivity.

Diverging Surface seawater

Surface Seawater moves away. Deeper seawater (cooler, nutrient rich) replaces surface water. UPWELLING. High biological productivity.

Ekman Spiral

Surface currents move at an angle to wind. Describes speed and direction of seawater flow at different depths.

Subtropical High-Pressure Cells

Westerlies, Bermuda High, Azores High, Pacific High. System migrates with the summer high sun. Between 20 and 35 in both hemispheres. Hot and dry. Dynamic

Causes of horizontal pressure variations

Thermal: High Temperature = Low pressure. Low Temperature = High Pressure. Dynamic: Rising Air = Low pressure on surface. Falling air = High pressure on Surface.

Western Intensification

Top of hill of water displaced toward west due to earth's rotation. Currents become: Faster, narrower, deeper, and warmer.

Surface Ocean Currents

Transfer heat from warmer to cooler areas. Affect coastal Climates Similar to pattern of major wind belts.

Deep Current motion&driving factor

Vertical & horizontal motion. Driven by differences in density caused by differences in temperature and salinity.

Rossby Waves

Within westerly flow winds are great waving undulations. Bring cold air southward & warmer air northward. Develop along the flow axis of a jet stream.

Isobar

an isoline (a line along which there is a constant value) plotted on a weather map to connect points of equal pressure.

Changes in thermohaline circulation

causes global climate change.

Coriolis force

deflective force, makes wind that travels in a straight path appear to be deflected in relation to Earth's rotating surface. The coriolis force deflects wind to the right in the northern hemisphere and to the left in the southern hemisphere. Without it winds would move along straight paths between high and low pressure areas. Affects only the direction of movement.

Hadley Circulation

denotes the circuit completes by winds rising along the ITCZ.

Pressure Gradient force

drives air from areas of higher barometric pressure (more dense air) to areas of low barometric pressure (less dense air), thereby causing winds. Without it there would be no wind.

High pressure gradient force

fall and spread.

Wind

horizontal movement of air.

O2

important for life and mineral processes in deep ocean currents.

Cold surface water

sinks at polar regions and moves towards the equator.

Earth's rotational speed

varies with latitude. increasing from 0 kmph at the poles (surface is at earth's axis) to 1675 km/h at the equator (surface farthest from Earth's axis).

Trade winds

winds converging on the equatorial low-pressure trough.