EAE3142 Tropical meteorology

Tropical weather is very different from that in the mid and higher latitudes. For example, compared with the mid and higher latitudes, temperature and pressure gradients are (mostly) very weak in the tropics. This unit describes the key properties of the tropical atmosphere and explains the science underpinning tropical climate and weather. The governing equations of motion are introduced and the approximations relevant to the tropics described and justified. The most important of these approximations, and the fundamental reason for the differences between the tropics and the mid and higher latitudes, is that the effect of the earth's rotation (as expressed through the Coriolis force) is small in the tropics. Another important distinction between the tropics and elsewhere is that the atmosphere is more strongly coupled to the ocean. The approximated equations of motion will be used to explain the Hadley circulation, equatorial waves and the El Nino - Southern Oscillation, and these explanations compared in detail with observation. Unlike the midlatitudes, moist convection is essential in understanding the weather and climate of the tropics. For this reason emphasis will be placed on the parts played by convection and radiation in driving the large-scale circulation and in producing locally important weather. The unit concludes with an examination of tropical cyclones, perhaps the most destructive weather system on the planet.