What primary factors contribute to global patterns of temperature, air circulation, and ocean circulation?
Amount of sunlight per unit area: Sun is directly overhead at the equator, but hits the poles at an angle. Thus, the equator recieves more sunlight per unit area. Hadley cells: Direct sunlight on equator heats the air, which begins to rise. As the air rises it cools. Cool air can hold less moisture than warm air, so the air drops most of its moisture over the equator. The rising cool air is pushed towards the poles by the warm air rising under it. When it reaches about 30 degrees latitude, i t begins to warm and sink again. The air has already dropped most of its moisture, and now that it is warm again its capacity to hold moisture is increased, so it rarely rains at 30 degrees latitude. This dry hot air is why most deserts are at 30 degrees latitude. The air then returns to the equator and starts the cycle over again. Prevailing winds: Earth’s rotation imposes direction on wind systems, which in turn affect surface temperature and evaporation. gyres: circular surface currents in ocean
