Estimated time: 5–10 minutes. Includes the activity and its built-in responses. Extra assignments may take longer.

Why the Subtropics Are Dry

Earth, the Hadley circulation, and the dry belt over North Africa and Southwest Asia A globe centered on Africa and the Arabian Peninsula. Moist trade winds converge at the equatorial low, rise, and move poleward aloft. Dry air descends into subtropical high pressure near 30 degrees north over the Sahara and Arabian Peninsula. Animated dots show the direction of airflow. DRY AIR sinks, warms, clears MOIST AIR rises, cools, makes rain HIGH PRESSURE · 30°N LOW PRESSURE · EQUATOR Sahara + Arabian Peninsula SURFACE TRADE WINDS dry at first, then moisten over ocean ALOFT: AIR MOVES POLEWARD AND DRIES 30°N 0° 30°S moist / wetter air dry air