Air Masses[High In The Air]

1. What are the 4 main types of air masses? What does each letter stand for?

mT= Maritime Tropical
mP= Maritime Polar
cP = Continental Polar
cT = Continental Tropical
A = Arctic
H = Highland

2. Which kind of air mass is most likely to bring hurricanes? Why?

mT because hurricanes form often in the late summer when temperature are warm enough to provide moisture and heat to the air.

3. Which kind of air mass(es) is most likely to bring a drought? Why?

cT and mT

4. Which kind of air mass(es) bring lake-effect snowstorms? (check p. 561)

cP and A

5. Today we learned about the 4 main types of air masses. In reality, there are many more than four. List and explain 2 other air masses.


Arctic

The source region for A air is northern Canada. It has the same characteristics as Polar air except it is colder with even lower dewpoints. This air often forms when a high pressure area becomes nearly stationary over Eastern Alaska and the Yukon. Due to a near lack of winter solar radiation, abundant surface snow/ice cover and the continuous emission of radiation from the Earth's surface the air will progressively become colder and colder. Temperatures can reach -30 ° F to -60 ° F. If the jet stream becomes meridional during the same time frame Arctic air builds, very cold air will spread into Southern Canada and the US. Once Arctic air moves into the Southern US it modifies to Polar air and then eventually to modified Polar Air behind the cold front boundary.

Highland

This air mass occurs in regions with large elevation changes over short distance. It is not a source region for one particular type of air mass. Since highland climates are in an elevated terrain, they can promote dryness in the interior of the highland climate. When air masses enter a highland climate they modify due to these elevation changes. mP and mT air is dried (on lee-ward side) due to orographic descent. cP air has difficulty entering a highland climate due to the high density of the cP air. Cold dense air has difficulty moving over elevated terrain.