Download Weather - SCIENCE!

Survey
yes no Was this document useful for you?
   Thank you for your participation!

* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project

Transcript
Weather
Weather changes as air masses move
Air masses are large bodies of air
• Air mass- a large volume of air in which
temperature and humidity are nearly the
same in different locations at the same
altitude
• Air masses take on the characteristics of
the Earth below them and takes them to
new locations
Characteristics of an Air Mass
• Air mass names contain two words
– First describes the area where the air mass
formed
• Continental-forms over land, dry
• Marine- forms over water, moist
– Second describes how close to the equator
the air mass formed
• Tropical-near the equator, warm land and water
• Polar- far from the equator, cold land and water
Movement of an Air Mass
• Air masses:
– Travel away from the area where they form
– Move west to east along the jet stream
– Fast moving air masses do not take on the
characteristics of the land below
Weather changes where air
masses meet
• Front- boundary between air masses
• Cold Front
– Move into regions quickly
– Push warm air up, water vapor condenses
forming clouds
– Produces precipitation
– Cooler air arrives
• Warm Front
– Move slowly
– Rises above cold front forming clouds
– Produces many hours or rain or snow
– Leaves warmer air behind it
• Stationary Front
– Occurs where air masses first meet or when
cold or warm fronts stop moving
– Air moves sideways or upwards along the
front
– Produces cloud cover for days
– Becomes either a warm or cold front when
one air mass advances
High Pressure Systems
• Formed when an air moves all the way
around a high pressure system
• Large and change slowly
• Generally brings clear skies and calm air
• Can form air masses (warm or cold)
Low Pressure Systems
• Large weather system that surrounds a
center of low pressure
• Air rises quickly producing stormy weather
• Usually from along the boundary between
a warm and cold front