Currents and ClimateCurrents and Climate

Currents and ClimateCurrents and Climate

• There are two types of currents:There are two types of currents:– SurfaceSurface– DensityDensity

Surface CurrentsSurface Currents

• Affect only water to a depth of 100mAffect only water to a depth of 100m• Are cold or warm depending on their Are cold or warm depending on their

starting location.starting location.• Caused by the windCaused by the wind

– Due to the spinning of the Earth the Due to the spinning of the Earth the currents in the Northern Hemisphere currents in the Northern Hemisphere curve to the right (clockwise), and in the curve to the right (clockwise), and in the Southern Hemisphere curve to the left Southern Hemisphere curve to the left (counter clockwise). This factor is called (counter clockwise). This factor is called the Coriolis Effect.the Coriolis Effect.

Surface CurrentsSurface Currents

Currents and ClimateCurrents and Climate

• As the currents in the oceans move past As the currents in the oceans move past the continents, they affect the climate on the continents, they affect the climate on land.land.

• The Gulf Stream brings warm water to The Gulf Stream brings warm water to areas in the North Atlantic that should not areas in the North Atlantic that should not be that warm. (British Isles, Iceland)be that warm. (British Isles, Iceland)

• Cold Currents in the Pacific make the Cold Currents in the Pacific make the ocean off the Wash./Oregon coast ocean off the Wash./Oregon coast extremely cold, even in the summer.extremely cold, even in the summer.

Density CurrentsDensity Currents

• These are deep currents that cause water to These are deep currents that cause water to creep along the bottom of the ocean floor.creep along the bottom of the ocean floor.

• The cold waters near the poles, sinks to the The cold waters near the poles, sinks to the bottom; while the warm tropical waters near bottom; while the warm tropical waters near the equator bring the water to the surfacethe equator bring the water to the surface

• These currents move and mix the water around These currents move and mix the water around the planet. It may take 1000 years for the the planet. It may take 1000 years for the water at the poles to move to the equator.water at the poles to move to the equator.

Density Currents Density Currents (Deep water (Deep water Current)Current)

Deep water current (side Deep water current (side view)view)

UpwellingsUpwellings

• Sometimes very fast moving winds or a Sometimes very fast moving winds or a storm will push away the top layers of storm will push away the top layers of the water. (Very small isolated areas.)the water. (Very small isolated areas.)

• This allows the cold, nutrient rich water This allows the cold, nutrient rich water near the bottom to reach the surface.near the bottom to reach the surface.

• The fish flock to that area because of The fish flock to that area because of the high nutrient content, and it makes the high nutrient content, and it makes for great fishing !!!for great fishing !!!

TidesTides

• Tides are caused by the interaction Tides are caused by the interaction of the sun, moon, and the Earth.of the sun, moon, and the Earth.

• Gravity is pulling the Earth towards Gravity is pulling the Earth towards the moon and towards the Sun. It’s the moon and towards the Sun. It’s what keeps us in our orbit!what keeps us in our orbit!

• That pull of gravity, causes the water That pull of gravity, causes the water on the Earth to be pulled further in on the Earth to be pulled further in one direction at different times of the one direction at different times of the month.month.

Daily TidesDaily Tides

• Every day there are high tides and low tides. Every day there are high tides and low tides. At the Jersey Shore, there are 2 high tides At the Jersey Shore, there are 2 high tides and 2 low tides every day.and 2 low tides every day.

• Why would it be important to know the Why would it be important to know the times of these tides?times of these tides?

Semidiurnal tidesSemidiurnal tides

• As the earth turns upon its own axis in about 24 As the earth turns upon its own axis in about 24 hours, a point on the earth moves through areas with hours, a point on the earth moves through areas with these different forces acting on it. In one rotation (one these different forces acting on it. In one rotation (one day), a point on earth travels from an area of high tide day), a point on earth travels from an area of high tide (where there is a force pulling water outward), (where there is a force pulling water outward), through an area of low tide, through and area of high through an area of low tide, through and area of high tide again (the opposite pull), and through another tide again (the opposite pull), and through another area of low tide, before it returns to the point of origin area of low tide, before it returns to the point of origin at high tide. This results in two high tides and two low at high tide. This results in two high tides and two low tides in a day (called semidiurnal tides).tides in a day (called semidiurnal tides).

Monthly tidesMonthly tides

• The changes of the alignment of the The changes of the alignment of the Earth, Sun and the Moon will cause Earth, Sun and the Moon will cause the tides to be greater than normal the tides to be greater than normal or lower than normal.or lower than normal.

• There are two types of monthly There are two types of monthly Tides: Spring Tides and Neap TidesTides: Spring Tides and Neap Tides

TidesTides

Spring Tide

Neap Tide

Tidal RangeTidal Range

• The tidal range is the measured distance The tidal range is the measured distance between the high tide and the low tide.between the high tide and the low tide.

Spring TidesSpring Tides

• The Sun, the Moon, and the Earth are The Sun, the Moon, and the Earth are all in a straight line.all in a straight line.

• Results in the highest high tides, and Results in the highest high tides, and the lowest low tides (twice a month)the lowest low tides (twice a month)

• Greatest tidal range during the Greatest tidal range during the monthmonth

Neap TidesNeap Tides

• The Sun, the Moon, and the Earth are The Sun, the Moon, and the Earth are at right angles to each otherat right angles to each other

• That makes the lowest high tides and That makes the lowest high tides and the highest low tidesthe highest low tides

• The Tidal Range is the smallestThe Tidal Range is the smallest