In recent posts concerning population growth, mention was made of the
variations of the average temperature of the earth. Does anyone know how
"average temperature of the earth" is defined and measured by
meteorologists? If some kind of grid is overlaid on the earth, and a
temperature measured at some point in each cell, what is the resolution of
that grid? What brought this to mind, was the fact that I live in foggy San
Francisco, where the average summer temperature might be 65 degrees
Fahrenheit, while in sunny Sausalito, just across the Golden Gate Bridge,
the average summer temperature might be 90 degrees Fahrenheit. If we're in
the same grid cell (as could easily be the case) would it make any sense to
talk about _a_ representative temperature of that cell? How about altitude?
Is the average temperature defined at some uniform altitude above the
earth's surface or is altitude simply ignored?
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Paul Goodman
San Francisco, CA
pgoodman@a.crl.com