Chapter 5 - Pressure Systems Flashcards
What is another name for the heat equator?
ITCZ (Intertropical Convergence Zone)
What occurs at the ITCZ
Low pressures which causes convection = thunder storms
Where is the Hadley Cell and what happens in it
Insolation occurs heating the surface Air rises in the equatorial region creates low pressure air cools diverges at the tropopause cool air sinks
Where is the Ferrell Cell
air sinks at the subtropical highs 30-40 degrees
then diverges
Converges at the polar lows
What happens at a Thermal/Heat Lows in the summer over land
Land heats intensely
Air converges and rises
diverges at the tropopause
Where do thermal/heat lows occur in the winter?
Over water because the sea holds warming temperatures than the air above
Orographic Low happens how
Where you have a mountain range On coming air hits the range creating high pressure is then false to go around the range cannot meet directly after the range creates an area of low pressure
Unstable air + Orographic Low
Thunderstorms
What is a Blocking High
Strong high pressure stops low pressure systems
In the northern hemisphere where would you find a cold high and what is it
Siberian High
An area where the core of air is cool
Causes high pressure lower down
What is a cyclone
A low pressure system
In the northern hemisphere where would you find a warm high and what is it
The Azores High
An area where the core of air is warm
Causes high pressure
What Weather do you associate with low pressures
Good Visibility - expect showers
Significant Cloud
Significant Precipitation
Small diurnal variation of temperature
What weather do you associate with high pressure
Light winds Poor Visibility - fog, mist or haze Little cloud No precipitation Large Diural variation of temperature
What is a flat pressure gradient
Isobars very wide apart.
Warm air can easily convect
very light winds
