The Jet Stream and The Jet Stream and Ocean CurrentsOcean Currents

Earth Science Earth Science

Mr. Cloud Mr. Cloud

General Circulation in the Troposphere

Prevailing Winds Prevailing Winds

Winds that blow from a certain Winds that blow from a certain compass direction for a large part compass direction for a large part of the yearof the year

Affected by Earth’s rotation Affected by Earth’s rotation (Coriolis Effect)(Coriolis Effect)

Otherwise known as Otherwise known as planetary planetary windswinds..

Example: prevailing westerlies Example: prevailing westerlies

MonsoonsMonsoons

A wet day in Mumbai, India (summer monsoon)

In summer, the sun’s intensity is greatest over Asia. This creates a region of low pressure that rises from the land, sinks to the ocean, and brings extreme moisture in its return.

In winter, insolation has its greatest intensity south of the equator. This creates a region of low pressure that rises from the south, sinks over Asia, and brings dry, cool weather to the region.

Jet Streams are caused by extreme pressure gradients between polar

and equatorial air masses.

Jet streams follow the boundaries between hot and cold air.

The 50°-60° N/S region is where the polar jet is located with the subtropical jet located around 30°N.

Temperature changes the greatest in these areas causing extreme differences in air pressure.

As the difference in temperature between the two locations increase, the strength of the wind increases

General Location of the Polar and General Location of the Polar and Subtropical Jet Stream in Summer (N. Subtropical Jet Stream in Summer (N.

Hemisphere)Hemisphere)

Surface Ocean Surface Ocean CurrentsCurrents

What causesWhat causes Ocean Currents to Ocean Currents to

flow?flow? Break it down!Break it down! Earth is sphericalEarth is spherical causes uneven heating of the Earthcauses uneven heating of the Earth causes convection in the tropospherecauses convection in the troposphere establishes Earth’s pressure beltsestablishes Earth’s pressure belts produces prevailing windsproduces prevailing winds drags upon the ocean’s surface drags upon the ocean’s surface

causing the water to move! causing the water to move!

Types of Ocean Types of Ocean Currents Currents Cold CurrentCold Current originate in polar regions and flow originate in polar regions and flow

towards the equatortowards the equator Warm currentWarm current originate in equatorial regions originate in equatorial regions

and flow towards the polesand flow towards the poles

Ocean Currents: What Ocean Currents: What direction do they flow?direction do they flow? Northern HemisphereNorthern Hemisphere: : clockwiseclockwise

Southern HemisphereSouthern Hemisphere:: counterclockwisecounterclockwise

Warm, tropical waters travel in a clockwise direction due to the prevailing winds and Coriolis Effect.

Color enhanced image of the Gulf Stream.