Redistribution of energy by atmospheric and oceanic circulation Flashcards
Atmospheric Circulation
Warm air rises at the equator forming a low pressure, it travels in the atmosphere to about 30 degrees north and south and sinks to form the Hadley cell. Some of the air returns as surface NE or SE Trade winds to the Equator. Air moves from the tropical high to low pressure areas. Cold air sinks at the Poles and flows outwards towards the Equator. The cold air from the poles is warmed as it travels southward causing air to rise at approximately 60 degrees North or South this creates the Polar Cell. The Polar and Hadley cells are thermally direct. The cold air from the poles meets warmer air from the tropics, causing the air to rise, creating the ferrell cell. Depressions and associated jet streams moving eastwards deform the ferrell cell. Due to the Coriolios force, winds are deflected. It is in this way that warm air from the equator is distributed to higher and cooler latitudes.
Oceanic circulation in the Atlantic
Currents follow circular loops called gyres, these move clockwise in the Northern Atlantic. In the Northern Atlantic warm water currents travel north e.g. the North Atlantic Drift. While cold water currents move southwards e.g. the Labrador. Ocean currents are greatly influenced by the prevailing winds, with energy being transferred by friction. The ocean currents are also affected by the configuration of land masses which deflect the ocean currents. Due to differential heating, density differences occur in water, resulting in chilled water sinking, spreading towards the Equator and displacing upwards the less dense warmer water. Their is also a clockwise movement as a result of the Coriolis effect.
