Polar cell
Topic: Atmospheric Pressure, Winds and General Circulation · NCERT: Class 11, Ch 9 "Atmospheric Circulation and Weather Systems"
Meaning
The polar cell is the loop of air nearest each pole. Very cold, dense air sinks over the pole and builds the polar high. Near the ground, this air flows out towards about 60° latitude. The Coriolis force bends it into the polar easterlies. At about 60°, the air meets the westerlies, rises at the subpolar low and flows back towards the pole high up. Like the Hadley cell, it is a direct thermal cell, because temperature drives it. Here, cold air sinks.
Example
Over Antarctica, cold air sinks above the ice sheet and flows outwards as easterly winds. It rises again over the Southern Ocean near 60°S, in the subpolar low belt.
Don't confuse with
- Polar vortex: a large area of low pressure and cold air that spins around the pole high up, in the stratosphere and upper troposphere. It is not a vertical loop of surface winds.