Clarifying the relationship between pressure and temperature?

Question

From the ideal gas law, we are aware that PV = nRT, which seems to suggest a direct relationship between pressure and temperature, or that as temperature increases, pressure increases.
In my geography book, however, it is written that "The equator receives direct rays of the Sun, this causes the temperature to rise, hence causing an equatorial low-pressure region." Later the book writes that "Colder air causes a higher pressure." Not just this, when I plotted data between sea level pressure, and average temperature for a weather station in New York, the plot I got was this which seems totally counter-intuitive to the direct relationship suggested by the ideal gas law.

Can someone please help me fix this conundrum?

niels nielsen · Answer

The ideal gas law takes no account of weather patterns over land and water; it takes no account of atmospheric circulation. So the connection you attempt to draw between the gas law and weather reporting is invalid.
Furthermore, the gas law's relationship between temperature and pressure you cite requires that the volume be held constant. No such rule obtains when describing air circulation patterns in the atmosphere.

Clarifying the relationship between pressure and temperature?

One Answer

Add your own answers!

Ask a Question