Thermal
（重定向自Thermal column）
A thermal column (or thermal) is a column of rising air in the lower altitudes of Earth's atmosphere. Thermals are created by the uneven heating of Earth's surface from solar radiation, and are an example of convection, specifically atmospheric convection. The Sun warms the ground, which in turn warms the air directly above it. Dark earth, urban areas, and roadways are good sources of thermals.