Soil Moisture and Drought
Susan Byrne, NASA GSFC
Soil moisture plays an important role in preventing or prolonging summer droughts. When the ground is wet, water evaporates as the day warms up. The warm, moist air rises until it encounters colder air high above the Earth's surface, leading to afternoon rainshowers. The water remains in the ground through the cool night, and the cycle repeats the next day. For more information, see Dry Times in North America.