Is it warmer at the top of tall buildings?
Dear Cecil:
Every winter my mind drifts to thoughts of the balmy shores of Rio. But do we really need to go so far for relief? My friend says that at the top of tall buildings it's a lot warmer. Is this true? When it's blizzarding down below can I go up to the top of the Sears Tower in Chicago with a bottle of Coppertone and a beach towel?
Cecil replies:
Sure, but don't expect to get any warmer. Temperature doesn't increase with height, it drops. That's why we see snow on mountain peaks in the summertime (or at least until late in the spring). As a rule the temperature drops about 3½ degrees Fahrenheit for every 1,000 feet of elevation, which means that at the top of 1,454-foot-tall Sears Tower the outside air temperature is about five degrees cooler than at ground level.
There are several reasons for this. The lower portion of the atmosphere (the troposphere) is mostly warmed by heat radiating from the earth, so up to a point the farther you get away from the earth the cooler you get. There's also the matter of adiabatic cooling. Atmospheric pressure decreases with height, since there's less air pressing down from above, and lower pressure = lower temp.
