What Are Geostrophic Currents

Contents

What is meant by a geostrophic current?

Definition of Geostrophic current:

A current controlled by a balance between a pressure-gradient force and the Coriolis deflection.

What causes geostrophic currents?

This occurs because the Earth is rotating. The rotation of the earth results in a “force” being felt by the water moving from the high to the low known as Coriolis force. The Coriolis force acts at right angles to the flow and when it balances the pressure gradient force the resulting flow is known as geostrophic.

What are geostrophic currents quizlet?

Geostrophic Flow. A current in the atmosphere in which the Coriolis force and the pressure gradient are in balance. determining velocity of upwelling. measuring isobaric and isoclinic slopes. Topography.

What is meant by geostrophic?

Definition of geostrophic wind

: a wind whose direction and speed are determined by a balance of the pressure-gradient force and the force due to the earth’s rotation.

What is the geostrophic current and how is it produced?

geostrophic current An ocean current that is the product of a balance between pressure-gradient forces and the Coriolis effect. This produces a current flow along the pressure gradient.

What is the largest Geostrophic current?

The Antarctic Circumpolar Current

Is Geostrophic current A surface current?

Most major surface currents are a combination of wind-driven and geostrophic currents. Since winds can be variable geostrophic flow ensure that the gyre currents keep moving at a fairly constant rate even when the wind dies down.

Are there any non geostrophic currents?

Not all currents are geostrophic

At smaller scales the ageostrophic (non-geostrophic) components of the currents for instance due to the forcing by the local wind become more and more important. So for instance in several coastal areas the circulation is largely ageostrophic.

How much is a Sverdrup?

In oceanography the sverdrup (symbol: Sv) is a non-SI metric unit of flow with 1 Sv equal to 1 million cubic metres per second (260 000 000 US gal/s) it is equivalent to the SI derived unit cubic hectometer per second (symbol: hm³/s or hm³⋅s⁻¹).

What forces are responsible for currents?

Ocean currents can be caused by wind density differences in water masses caused by temperature and salinity variations gravity and events such as earthquakes or storms. Currents are cohesive streams of seawater that circulate through the ocean.

What is a Geostrophic gyre quizlet?

The horizontal movement of surface water arising from a balance between the pressure gradient force and the Coriolis force is known as geostrophic flow. As noted earlier viewed from above geostrophic flow in a subtropical gyre is clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere.

What direction is the flow in gyres quizlet?

Gyres are closed circulation loops within the ocean. What are SUB-TROPICAL Gyres? Gyres which flow clockwise (anti-cyclonic) in the Northern Hemisphere.

What is the example of geostrophic wind?

The common example is that of an artillery shell fired a long distance. It will land somewhat to the right (in the northern hemisphere) of the expected path if the coriolis force is not taken into account. Although the shell is on a ballistic arc it appears to curve to the right to an observer on the earth’s surface.

Where do geostrophic winds occur?

The geostrophic wind is the wind flow that occurs in the middle latitudes aloft in the troposphere. The winds have a more difficult time obtaining geostrophic balance in the equatorial latitudes since the Coriolis force is weak.

What is the other name of Coriolis force?

Coriolis force also called Coriolis effect in classical mechanics an inertial force described by the 19th-century French engineer-mathematician Gustave-Gaspard Coriolis in 1835.

What causes upwelling currents?

Upwelling is an oceanic process in which cold water from the deep rises toward the surface of the ocean. It is caused by strong winds and the rotation of the Earth which moves warmer surface waters offshore allowing the cold nutrient rich water to rush up.

See also what is sedimentation in science

Do all ocean currents move at the same speed?

Currents are often affected by the shape of the ocean floor. Some move quickly while others move more slowly. A current can also change somewhat in depth and speed over time. Surface ocean currents can be very large.

Are gyres Geostrophic?

The horizontal movement of surface water arising from a balance between the pressure gradient force and the Coriolis force is known as geostrophic flow. As noted earlier viewed from above geostrophic flow in a subtropical gyre is clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere.

Is the North Pacific current warm or cold?

The North Pacific Current is a slow warm water current that flows west-to-east between 30 and 50 degrees north in the Pacific Ocean.

What is a surface current?

Surface currents are currents that are located in the upper 1 300 feet of the ocean as opposed to deep in the ocean.

Why do ocean gyres exist?

Three forces cause the circulation of a gyre: global wind patterns Earth’s rotation and Earth’s landmasses. Wind drags on the ocean surface causing water to move in the direction the wind is blowing. The Earth’s rotation deflects or changes the direction of these wind-driven currents.

Why is downwelling important?

Why is downwelling important? It brings down oxygen that animals in deeper water need. Why is upwelling important? It brings up nutrients that algae and other animals need that live close to the surface.

What are deep ocean currents caused by?

In contrast to wind-driven surface currents deep-ocean currents are caused by differences in water density. The process that creates deep currents is called thermohaline circulation—“thermo” referring to temperature and “haline” to saltiness.

What is the strongest type of ocean current?

The Antarctic Circumpolar Current

The Antarctic Circumpolar Current is the planet’s most powerful and arguably most important current. It is the only current to flow clear around the globe without being diverted by any landmass.

Are curves in the geostrophic winds?

For the wind to follow a curved path the wind is not in geostrophic balance. For wind to travel in a cyclonic curved path it curves to the left of straight line motion. This requires that the pressure gradient force be stronger than the coriolis force.

What does it mean when isobars are close together?

The lines around high and low pressure on a weather map are called isobars or lines of equal pressure as shown in the above image on the left. When isobars are close together it is very windy when they are further apart conditions are more calm. The wind around highs always blows in a clockwise direction.

Which is true of high pressure areas?

A high pressure system has higher pressure at its center than the areas around it. Winds blow away from high pressure. Swirling in the opposite direction from a low pressure system the winds of a high pressure system rotate clockwise north of the equator and counterclockwise south of the equator.

How many Sverdrups is the Amazon River?

1 000 000 cubic metres of water per second equals one sverdrup. It’s a unit named after Harald Sverdrup a Norwegian oceanographer. (He’s also the namesake of the Sverdrup balance an important precursor to our understanding of global ocean flow.) The discharge of the Amazon River into the ocean equals 0.29 sverdrups.

How big is a sverdrup?

Sverdrup (Sv) is the basic unit of volume transport used in physical oceanography and is equal to one million cubic meters of water flowing per second.

What is a sverdrup used for?

The sverdrup is used to appraise the volumetric rate of evaporation precipitation runoff transport of ocean current and so on. Its symbol is Sv which should not be confused with the SI unit sievert and the non-SI unit svedberg both having the same symbol.

What are the causes of currents?

Oceanic currents are driven by three main factors:

The rise and fall of the tides. Tides create a current in the oceans which are strongest near the shore and in bays and estuaries along the coast. …
Wind. Winds drive currents that are at or near the ocean’s surface. …
Thermohaline circulation.

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How do currents work?

How are surface currents formed?

Surface currents are created by three things: global wind patterns the rotation of the Earth and the shape of the ocean basins. Surface currents are extremely important because they distribute heat around the planet and are a major factor influencing climate around the globe.

What is the name of the transverse current in the tradewinds in the North Pacific ocean?

The North Equatorial Current (NEC) is a westward wind-driven current mostly located near the equator but the location varies from different oceans. The NEC in the Pacific and the Atlantic is about 5°-20°N while the NEC in the Indian Ocean is very close to the equator.