Oceanography Chapter 7

Southern Boundary Currents

Southern part of subtropical gyres

Eastern Boundary Currents

Cold current that is slow, wide and shallow

Younger Dryas Event

A cold episode that took place about 11,000 years ago, when average temperatures dropped suddenly and portions of the Northern Hemisphere reverted back to glacial conditions.

La Nina

A coupled ocean-atmosphere phenomenon that is the counterpart of El Niño as part of the broader El Niño-Southern Oscillation climate pattern

Geostrophic Current

A current that forms as a result of gravity and the coriolis effect as water flows down a geostrophic hill.

North Atlantic Drift

A warm ocean current that brings warm, moist air across the Atlantic Ocean to Northern Europe

Dryas octopetala

Alpine plant with white flowers typically found in arctic regions. Evidence of its presence in current day Scandinavian forests is evidence of recent major changes in Earth's climate

Productivity

An abundance of microscopic algae, aided by upwelling of nutrient-rich water

AMOC

Atlantic Meridional Overturning Circulation. The driver of the conveyor belt circulation in the Northern Atlantic

ENSO index

Calculates El Nino/ La Nina patterns

Surface Currents

Currents that affect water to a depth of several hundred meters. They are driven mainly by wind.

North Atlantic Deep Water

Deep water mass formed in the North Atlantic Ocean. Thermohaline circulation of the world's oceans involves the flow of warm surface waters from the southern hemisphere into the North Atlantic

Antarctic Bottom Water

Densest water in the open ocean

Ekman Spiral

Describes the speed and direction of flow of surface waters at various depths

Downwelling

Downward movement of surface water to deeper parts of the ocean

Antarctic Divergence

East wind drift is deflected towards the continent, and antarctic circumpolar current is deflected away from it

Warm-core rings

Eddies that rotate clockwise

Cold-core rings

Eddies that rotate counter clockwise

Benguela Current

South Atlantic gyre, Eastern boundary. Slow moving and cold current that flows south to North along the western coast of Africa

Ocean Currents

Global patterns created from the movement of the oceans; such as the Gulf Stream

Gyres

Huge circular moving current systems dominate the surfaces of the oceans.

Atlantic meridional overturning circulation

Important component of the Earth's climate system, characterized by a northward flow of warm, salty water in the upper layers of the Atlantic, and a southward flow of colder water in the deep Atlantic

South Pacific Subtropical Gyre

Includes Southern Equatorial, Peru, Southern Pacific and East Australian currents.

North Pacific Subtropical Gyre

Includes northern equatorial, Kuroshiro, Northern Pacific and California currents

Indian Ocean subtropical Gyre

Includes, Southern Indian, Western Australian, Southern Equatorial and Algulhas currents. There is only 1 gyre in the Indian ocean.

West Australian Current

Indian Ocean Gyre, Eastern boundary current. Merges with South Equatorial Current

Algulhas Current

Indian Ocean Gyre, Western boundary current. Flows southward along Africa's east coast

Lake Agassiz

Largest glacial lake in North America that covered much of Manitoba, northwestern Ontario, and eastern Saskatchewan

Antarctic Circumpolar Current/ West Wind Drift

Main current in Antarctica, circles around the continent and flows west to east

Equatorial Currents

Major ocean currents that move parallel to the Equator

Western Intensification

Makes western boundary currents faster, narrower, and deeper than the eastern boundary counterparts. A result of the Earth's rotation.

Ekman Transport

Net water movement that is 90 degrees from the direction of the wind. To the right in Northern hemisphere, to the left in Southern hemisphere

Canary Current

North Atlantic gyre, Eastern boundary current. Broad, cold, southward flow that eventually joins the North Equatorial Current

Gulf Stream

North Atlantic gyre, Western boundary current. World's most studied current

California Current

North Pacific Gyre, Eastern boundary current. Flows southward along the coast of California

Kuroshiro Current

North Pacific Gyre, Western boundary current. Makes Japan's climate warmer

Northern Boundary Currents

Northern part of subtropical gyres

Thermohaline Circulation

Part of the large-scale ocean circulation that is driven by global density gradients created by surface heat and freshwater fluxes.

East Australian Current

South Pacific Gyre, Western boundary, flows past Wallaby Way in Sydney.

Peru Current

South Pacific Gyre. Eastern boundary, Also known as: Humboldt current

Pacific Decadal Oscillation

Pattern of Pacific climate variability similar to ENSO in character, but which varies over a much longer time scale

Walker Circulation Cell

Pressure difference causes strong southeast trade winds to blow across the equatorial South Pacific Ocean

Labrador Current

Produces abundant fog in the North Atlantic. Flows to the South

North Atlantic Subtropical Gyre

Rotates clockwise. Gulf Stream, North Atlantic, Canary, Northern Equatorial currents

South Atlantic Subtropical Gyre

Rotates counterclockwise. Brazil, Antarctic Circumpolar, Benguela, Southern Equatorial currents

Monsoon

Seasonal reversing wind accompanied by corresponding changes in precipitation and currents in the Indian Ocean

Deep Currents

Slow, cold currents at the bottom of the ocean; caused by differences in density

Meanders

Snakelike bands in the current that often disconnect from the Gulf Stream and form large rotating masses of water called vortexes

East Wind Drift

Surface current propelled by the polar easterlies

V. Walfried Ekman

Swedish physicist who developed the Ekman spiral

Conveyer-Belt Circulation

The global ocean conveyor belt is a constantly moving system of deep-ocean circulation driven by temperature and salinity

Southern Oscillation

The seesaw pattern of atmospheric pressure between the eastern and western Pacific.

Subtropical Convergence

The zone of convergence that occurs within all subtropical gyres as a result of Ekman transport driving water toward the interior of the gyres.

Upwelling

Upward movement of cold, deep, nutrient rich water to the surface

Temperature-Salinity Diagram

Used to identify deep water masses based on their characteristic temperature, salinity, and density

Western Boundary Currents

Warm current that is fast, narrow and deep

El Nino

Warm phase of the El Niño Southern Oscillation and is associated with a band of warm ocean water that develops in the central and east-central equatorial Pacific, including off the Pacific coast of South America

Coastal Upwelling

Water rises from below to replace the water moving away from shore. Typically caused by offshore or side shore winds.

Eqatorial Upwelling

Water rises from below to replace water moving away from the equator to both the north and south due to Ekman transport. Water is colder and more productive than in most areas of the tropics.

Coastal Downwelling

Water stacks up along the shoreline and has nowhere to go but down. typically caused by onshore winds.

Pacific Warm Pool

Wedge of warm water on the western side of the Pacific Ocean caused by trade winds

Antarctic Convergence

Where colder, denser Antarctic waters converge with warmer, less dense sub Antarctic waters