| MadSci Network: Earth Sciences |
Hanh,The earth's surface is composed of dirt, rock, concrete, asphalt, etc., which has a higher heat capacity than air. This means that the air will lose heat faster than the ground.
When air temperature drops rapidly, such as after a cold front has passed, the ground temperature will fall much more slowly. This is one reason that snow or ice can melt on the ground even if the air temperature is below freezing.
However, suppose the ground has cooled off after several days of cold temperatures. If the airmass heats up quickly, the earth's surface will be slower to warm. This is also due to the difference in heat capacity, and can result in the earth's surface being colder than the air.
Try the links in the MadSci Library for more information on Earth Sciences.