reversing axis

[Sinead Done <sdone@xxxxxxxxxxxxxxxxxxx>]

Hi,

I have been plotting some data from a radiosonde (ie temperature and 
dewpoint on the x axis against pressure on the y axis), however, my plots 
all come out with pressure increasing on the y-axis. However, because I am 
plotting a profile of the atmosphere, I need the pressure the other way 
around (ie I need it to decrease with height).

Is there a command which can correct this?

Thanks,
Sinead