"Hilton" wrote in message
ink.net...
Hi,

How is standard temperature and pressure defined below sea level? How
does
DA increase/decrease below sea level? I know that the gravitation force
starts decreasing in a *linear* fashion below sea level, but how that
affect
the temp, pressure, and DA is beyond me. Any books, or URLs that could
help
me out here?


http://www.faa.gov/atpubs/SWO/chapter_14Sect2.htm

but it only has the standard pressures down to about -2700 feet, no
temperatures. Increments of .01 inches of mercury.


The following is much more coarse.... every 500 feet:

http://www.sablesys.com/baro-altitude.html

but it shows pressures AND Temperatures down to -5000 feet