Azman Shah (AAG 101)
What is the role of the Hadley cell in the earth's weather system?
Hadley Cells is a tropical atmospheric circulation pattern found in the tropics producing the tropical easterlies and the trade winds.
In it, warm moist air rises up into the atmosphere creating a band of low pressure at the equator (Near Equatorial Trough), due to the excessive radiation by the sun causing it to evaporate. With greater relative heating at tropical latitudes and lesser relative heating at higher latitudes, it creates different levels of pressure where it is higher in the tropics than at higher latitudes. This too results in the development of lower tropospheric, traveling along a meridian horizontal pressure gradient between high pressure in the subtropics and low pressure near the equator. Contrary, we will also see the pressure gradient being reversed nearer to the tropopause, leading to the easterly near-surface flow found in the tropics.
The heated air as mentioned, creates a flow of high-pressure air around 30 degrees latitude in both the tropics and subtropical region (Subtropical Ridge). This movement leads to the formation of the Northeast trade winds (Tropical Easterlies) moving towards the West in the Northern Hemisphere, region of the equator. Once the rising air reaches the top of the tropical troposphere at approximately 10-15 kilometres above the Earth's surface, it brings a halt to its rising motion of the air, forcing the air to diverge polewards on both sides of the equator.
Geostrophic balance plays one of the major parts in corresponding to the uncurved flow. This is when the pressure gradient force which is directed from high to low is balancing the Coriolis force where it is directed to the right of the motion in the northern hemisphere, causing the force from the centre...