Lecture 9: Global Circulation Patterns Flashcards
Earth’s energy balance
Surplus
Low latitudes
insolation is greater than OLR
Earths energy balance
Deficit
High latitudes
OLR is greater than insolation
High and low pressure areas
Tropics
Thermal L
more insolation and warm rising air
High and low pressure areas
Poles
Thermal H
cold, sinking air
High and low pressure areas
Subtropics
Dynamic H
air sinks
High and low pressure areas
Subpolar
Dynamic L
convergence of surface winds in pubpolar region
Trade winds
circulation in the tropics
prevailing winds that blow northeast from 30 degrees north latitude to the equator and that blow southeast from 30 degrees south latitude to the equator
Turns right in NH (northeast)
Turns left in SH (southeast)
Polar easterlies
prevailing winds that blow from east to west between 60-90 degrees latitude in both hemispheres
Westerlies
circulation mid latitude
dominant winds of the mid-latitudes, these winds move from the subtropical highs to the subpolar lows from west to east
air flows from subtropic H to subpolar low
Polar high
low pressure system found over ocean, polwards of both NH and SH
Subpolar low
winds generated by polar high converge with westerly winds from subtropical high at the subpolar low
Subtropical high
has high atmospheric pressure
Equatorial low
air is hot and expands, rising as convection causing low pressure to develop
Thermal L
rising air diverges aloft, moves polward
Dynamic L
convergence of surface winds in subpolar region
Thermal H
surface air diverges from poles, moves equatorward
Dynamic H
air sinks at subtropics
Circulation of wind systems: Trade winds
air flows toward equator to replace rising air (circulation in the tropics)
Turns right in NH (northeast trade winds)
Turns left in SH (southeast trade winds)
Circulation of wind systems
Westerlies
air flows from subtropical H to subpolar low and turns (westerlies in NH and SH) circulation in mid-latitudes
Circulation of wind systems
Easterlies
air moving away from polar H and turns (polar easterlies in NH and SH) circulation in high latitudes
Thermal properties
Tropics
air is rising making land warmer, results in thermal lows over land
Thermal properties
Subtropics
air is sinking making ocean cooler, results in thermal highs in ocean
Thermal properties
Subpolar
air is rising making ocean warmer, results in thermal lows in ocean
Thermal properties
Polar
air is sinking, making land cooler, results in thermal highs over land
Bermuda high
during NH summer, Bermuda high is very strong and directs hurricanes
