Re: Is the average air pressure in Death Valley lower than at sea level?

Since the pressure decreases with increasing altitude you can
expect it to increase with decreasing altitude, so, all other
things being equal, the pressure in Death Valley will be
higher.

To first approximation the pressure at an altitude of y
kilometers is, in atmospheres,

  p = exp(-ay)

where exp( ) is e raised to the power of whatever is in
the ( ).  The approximately constant "a" has the value
0.116 inverse kilometers when calculating not too far
from sea level.  I don't know the depth of Death Valley,
but with y below sea level you will have y being negative
so that the exponential will be positive.  For instance,
if y is -1 kilometers you get the pressure being about
1.12 atmospheres.

Hope this helps!

John Link
MadSci Physicist