Large-scale patterns organize heat and moisture across regions and around the planet. Examine atmospheric circulation, jet streams, monsoons, El Niño, and other connected systems that produce recurring variations in climate.
Many of the world’s great hot deserts occupy the subtropics: the Sahara and Arabian deserts in the Northern Hemisphere, and large arid regions of southern Africa, Australia, and South America farther south. Their clustering near 30 degrees latitude reflects a major feature of global atmospheric...
The Intertropical Convergence Zone is visible from space as an irregular belt of towering clouds and heavy rainfall near the equator. It forms where the trade winds of the Northern and Southern Hemispheres approach one another and air rises. The belt migrates north and south during the year, moving...
Cold, dense air tends to sink over the polar regions and spread toward lower latitudes near the surface. It does not travel all the way to the equator. Around the high latitudes, commonly near 60 degrees, it approaches milder air moving poleward through the midlatitudes. The shifting boundary...
Between the tropical overturning of the Hadley cell and the cold circulation surrounding the poles lies the Ferrel cell. In a long-term average, surface air moves poleward from the subtropics, rises in the vicinity of the polar front, returns equatorward aloft, and descends near 30 degrees latitude....
The Hadley cell is the dominant overturning circulation of the tropical atmosphere. It converts uneven solar heating into a broad pattern of rising air near the equator, poleward flow high in the troposphere, descent in the subtropics, and a return toward the equator near the surface. One such...