World's largest hot desert. Located in north Africa and covers over 3,500,000 square miles (9,000,000 sq km) or roughly 10% of the continent. Mean temperature over 30 degrees C. Variations may also be huge, from over 50 degrees C during the day, to temperatures below 0 at night in summer.
Fall begins (Northern H.) History. Fall begins in the Northern Hemisphere when the Sun is perpendicular to the equator. This day has equal hours of day and night. The first day of Fall is also called the Autumnal Equinox. In many areas it coincides with harvests. The first day of Fall happens between each year between September 22 and 24.
The Meteorologist Who Started a Revolution, Weatherwise 47 (April/May 1994) 29-35. I freely admit that in formulating the theory [of raindrop formation] I drew quite a lot on Alfred Wegener's ideas.. When Tor Bergeron acknowledged his debt to Alfred Wegener he spoke for all meteorologists.