The atmosphere and the ocean

Publisher Summary This chapter discusses the atmosphere and the ocean. The global wind system acts to redistribute heat between low and high latitudes. Winds blow from regions of high pressure to regions of low pressure, but they are also affected by the Coriolis force, to an extent that increases with increasing latitude. Because of the differing thermal capacities of continental masses and oceans, wind patterns are greatly influenced by the geographical distribution of land and sea. In mid-latitudes, the predominant weather systems are cyclones and anticyclones. At low latitudes, the atmospheric circulation consists essentially of the spiral Hadley cells, of which the trade winds form the lowermost limb. The Intertropical Convergence Zone (ITCZ), where the wind systems of the two hemispheres meet, is generally associated with the zone of maximum sea-surface temperature in the vicinity of the Equator. Heat is transported polewards in the atmosphere as a result of warm air moving into cooler latitudes. The ocean influences the atmosphere by affecting its moisture content, and hence its stability. Sea-surface temperatures influence the intensity of the Hadley circulation, and the position of ITCZ generally corresponds to the zone where sea-surface temperatures are the highest. The chapter concentrates on phenomena resulting from atmosphere–ocean interaction in the tropics where the two fluid systems are most closely “coupled.”