What kind of pressure system is this?

Question

A meteorologist draws a straight line west to east across a series of 500 millibar height countours on his map. Starting at the west end of the line, the heights are 5520 meters, 5460 meters, 5400 meters, 5400 meters, 5460 meters, and 5520 meters. What kind of pressure system lies under this series of countours?

Answer 1

I am glad you ask that kind of question because this is the kind of map I like to see myself. It is called a geopotential height map at 500 hPa (or 500 millibar, which is the same but the unit is now called hectoPascal).

500 hPa is about half way up in the troposphere and it is interesting to see what happens there because it is away from the influence of the surface. If the map also shows winds and temperature, you can also very clearly see the front between polar and temperate air masses, and the eventual jet-streams following it.

Anyway, when the pressure of 500 hPa is detected at higher and higher altitude it means that you are moving toward a high pressure. If you have also the temperature plotted you'll notice that high pressures tend to be warmer than the surrounding air and a low pressure, colder. That is because of the adiabatic cooling or warming as pressure changes.

Answer 2

Low pressure or cyclonic circulation.