With the aid of a diagram, describe and explain global pressure system and wind distributions.

Diagram - should include Hadley, Ferrel and Polar cells (with appropriate latitudinal pressure belts) along with trade and prevailing winds from their respective directions. - should be the descriptive part of the answer before explaining the diagramFor the purposes of the answer we're assuming an equinox with an angle of insolation of 90° at the Equator. The tri-cellular pressure model begins at the Equator which receives highly concentrated rays and thus is the latitude that heats up the most at this time. This excess heat encourages air to rise and therefore the pressure at the Equator is low. This rising air diverges in the upper atmosphere and cools adiabatically, sinking again at around 30°N and S of the Equator forming sub-tropical high pressure belts at these latitudes. This high pressure causes air to disperse Northwards and Southwards completing the Hadley cell.This answer would be fairly long as it's a broad question, but I'd go on to discuss the formation of the ferrel and polar cells from the diagram. Having set up latitudinal pressures, winds and wind directions can be explained using the pressure systems and the coriolis force.Other variables could be added to develop the answer such as mountain ranges, local heat capacities of land and sea and anthropogenic influences.