WHAT IS THE CORIOLIS EFFECT?

The Apparent Deflection of Objects Moving Across the Surface of the Earth from Their Intended Path. Derives from objects (air) passing across a moving frame of reference (the rotating latitude longitude grid of the world)

Instructions: Cut along dotted line! Earth Rotating in anti-clockwise direction

Circumference at Equator: 40,077km (24,905 miles). Rotates once per 24 hrs, thus linear velocity = 40,077/24 = 1670 km. hr -1 (1041 mph)

0° 40077km1670 km.hr -1 Lat. Circum.Velocity

0° 40077km1670 km.hr -1 10° 39548km1648 km.hr -1 Lat. Circum.Velocity

0° 40077km1670 km.hr -1 10° 39548km1648 km.hr -1 20° 37771km1574 km.hr -1 Lat. Circum.Velocity

0° 40077km1670 km.hr -1 10° 39548km1648 km.hr -1 20° 37771km1574 km.hr -1 30° 34797km1450 km.hr -1 Lat. Circum.Velocity

0° 40077km1670 km.hr -1 10° 39548km1648 km.hr -1 20° 37771km1574 km.hr -1 30° 34797km1450 km.hr -1 40° 30819km1284 km.hr -1 Lat. Circum.Velocity

0° 40077km1670 km.hr -1 10° 39548km1648 km.hr -1 20° 37771km1574 km.hr -1 30° 34797km1450 km.hr -1 40° 30819km1284 km.hr -1 50° 25876km1078 km.hr -1 Lat. Circum.Velocity

0° 40077km1670 km.hr -1 10° 39548km1648 km.hr -1 20° 37771km1574 km.hr -1 30° 34797km1450 km.hr -1 40° 30819km1284 km.hr -1 50° 25876km1078 km.hr -1 60° 20121km 838 km.hr -1 Lat. Circum.Velocity

0° 40077km1670 km.hr -1 10° 39548km1648 km.hr -1 20° 37771km1574 km.hr -1 30° 34797km1450 km.hr -1 40° 30819km1284 km.hr -1 50° 25876km1078 km.hr -1 60° 20121km 838 km.hr -1 70° 13749km 573 km.hr -1 Lat. Circum.Velocity

0° 40077km1670 km.hr -1 10° 39548km1648 km.hr -1 20° 37771km1574 km.hr -1 30° 34797km1450 km.hr -1 40° 30819km1284 km.hr -1 50° 25876km1078 km.hr -1 60° 20121km 838 km.hr -1 70° 13749km 573 km.hr -1 80° 6990km 291 km.hr -1 Lat. Circum.Velocity

0° 40077km1670 km.hr -1 10° 39548km1648 km.hr -1 20° 37771km1574 km.hr -1 30° 34797km1450 km.hr -1 40° 30819km1284 km.hr -1 50° 25876km1078 km.hr -1 60° 20121km 838 km.hr -1 70° 13749km 573 km.hr -1 80° 6990km 291 km.hr -1 Lat. Circum.Velocity All latitudes rotate with the same ANGULAR VELOCITY (360°/24hrs) 15°.hr -1. However LINEAR VELOCITIES change with latitude.

Rudolf’s View of half a Year’s Work! Earth Rotating in anti-clockwise direction

Trees are fixed frame of reference Merry-go-round is moving frame of reference Merry-go-round is rotating in anti- clockwise direction. Person in center of merry-go-round throws purple ball towards friend (red) on the merry-go- round Like Earth rotating in anti-clockwise direction

Moving frame of reference. Fixed frame of reference

Moving frame of reference. Fixed frame of reference

Moving frame of reference. Fixed frame of reference

Moving frame of reference. Fixed frame of reference

Moving frame of reference. Fixed frame of reference

Moving frame of reference. Fixed frame of reference

CORIOLIS EFFECT Objects moving across the surface of the Earth in the North hemisphere appear to be deflected to the right of their intended path.

CORIOLIS EFFECT Objects moving across the surface of the Earth in the North hemisphere appear to be deflected to the right of their intended path. Objects moving across the surface of the Earth in the South hemisphere appear to be deflected to the left of their intended path.

CORIOLIS EFFECT Objects moving across the surface of the Earth in the North hemisphere appear to be deflected to the right of their intended path. Objects moving across the surface of the Earth in the (?)South hemisphere appear to be deflected to the left of their intended path.

IS THE CORIOLIS EFFECT A GEOGRAPHIC VARIABLE? Does its effect vary over the surface of the Earth?

°N, San José 10° Very small decrease in radius. (& linear velocity)

°N, San José 20° Slightly larger decrease in radius. (& linear velocity) 20°N, Guantanamo

°N, San José 30° Slightly larger decrease in radius. (& linear velocity) 20°N, Guantanamo 30°N, Gainesville

°N, San José 40° Slightly larger decrease in radius. (& linear velocity) 20°N, Guantanamo 30°N, Gainesville 40°N, Philadelphia

°N, San José 50° Larger decrease in radius. (& linear velocity) 20°N, Guantanamo 30°N, Gainesville 40°N, Philadelphia 50°N, Southampton

°N, San José 60° Large decrease in radius. (& linear velocity) 20°N, Guantanamo 30°N, Gainesville 40°N, Philadelphia 50°N, Southampton 60°N, Reykjavik

°N, San José 70° Large decrease in radius. (& linear velocity) 20°N, Guantanamo 30°N, Gainesville 40°N, Philadelphia 50°N, Southampton 60°N, Reykjavik 70°N

°N, San José 80° Large decrease in radius. (& linear velocity) 20°N, Guantanamo 30°N, Gainesville 40°N, Philadelphia 50°N, Southampton 60°N, Reykjavik 70°N 80°N

°N, San José 90° Largest decrease in radius. (& linear velocity) 20°N, Guantanamo 30°N, Gainesville 40°N, Philadelphia 50°N, Southampton 60°N, Reykjavik 70°N 90°N 80°N

Change in linear velocities of various parallels of latitude (horizontal slices) increases with higher latitudes. Differences in linear velocities of the parallels cause the Coriolis effect, therefore the Coriolis effect is minimal at the Equator (small changes in linear velocities) and a maximum at the Poles (largest changes in linear velocities).

t = 0 Velocity Distance per unit time Acceleration Change in Velocity per unit time Time Distance Time Change in Velocity Distance per unit time Acceleration Change in Velocity per unit time Two truckers (yellow and blue trucks) meet at rest stop at the intersection of a North-South and an East West highway. The truckers are communicating by CB

t = 0 t = 1 Velocity Distance per unit time Acceleration Change in Velocity per unit time Time Distance Time Change in Velocity Distance per unit time Acceleration Change in Velocity per unit time FIXED FRAME OF REFERENCE (Yellow truck stationary) The blue truck leaves the rest stop heading north up the highway while the yellow truck stays at the rest stop. The truckers continue to communicate by CB, using the strength of the signal to measure how quickly they are moving apart (velocity) and how quickly that velocity is changing (acceleration). The Coriolis effect is an acceleration.

t = 0 t = 1 2 Velocity Distance per unit time Acceleration Change in Velocity per unit time Time Distance Time Change in Velocity Distance per unit time Acceleration Change in Velocity per unit time

t = 0 t = Velocity Distance per unit time Acceleration Change in Velocity per unit time Time Distance Time Change in Velocity Distance per unit time Acceleration Change in Velocity per unit time

t = 0 t = Time Distance Time Change in Velocity Distance per unit time Acceleration Change in Velocity per unit time

t = 0 t = Time Distance Time Change in Velocity Distance per unit time Acceleration Change in Velocity per unit time The “acceleration” term stays fixed at zero – i.e. blue truck moving away from yellow truck of fixed position at constant velocity (40 mph).

t = 0 t = Increase in Linear velocity Acceleration Change in Velocity per unit time Time Distance Time Change in Velocity Even if the blue truck goes at twice the velocity (80 mph), forcing the distance/time graph to the left, acceleration remains at zero (neither moving apart faster or slower).

t = Time Distance Time Change in Velocity + Distance per unit time Acceleration Change in Velocity per unit time MOVING FRAME OF REFERENCE ( Yellow truck also moving) The yellow truck heads East at the same speed (40 mph) as the blue truck is heading north. With the frame of reference (yellow truck) itself now moving the distance between the two increases more with each passing time period and so the velocity of their separation increases with time (blue up-turned function). The rate of this change (acceleration) is positive (increasing steadily). Coriolis is acceleration.

t = Time Distance Time Change in Velocity + Distance per unit time Acceleration Change in Velocity per unit time MOVING FRAME OF REFERENCE ( Yellow truck also moving)

t = Time Distance Time Change in Velocity + Distance per unit time Acceleration Change in Velocity per unit time MOVING FRAME OF REFERENCE ( Yellow truck also moving)

t = Time Distance Time Change in Velocity + Distance per unit time Acceleration Change in Velocity per unit time MOVING FRAME OF REFERENCE (blue truck having doubled its speed) The velocity of separation between the trucks is now greater ( steeper blue up turned function). The rate of this change (acceleration) is even more positive (increasing steadily). Acceleration increased. Coriolis effect is an acceleration.

CORIOLIS EFFECT The higher the linear velocity of the moving object (blue truck’s velocity) relative to the moving frame of reference (the yellow truck’s position), the greater the Coriolis acceleration. Winds blowing quickly (steep pressure gradient) will be deflected to a greater extent and those blowing slowly will be deflected less (lower pressure gradient)

Coriolis Effect proportional to: -2Ω. V. Sin (φ). where: Ω = angular velocity of earth (360°/24hrs) V = linear velocity of moving object Φ = latitude CORIOLIS EFFECT Quantitative Expression