ATS 113: Chapter 9 review questions
What are drylines and why are they important?
Drylines separate air masses with similar temps but different humidities, like cT and mT air masses. they can be responsible for a dramatic change of humidity w/o a corresponding change in temp. b/c of the diff heating of the air, the temp contrast is greatest in the afternoon, which can help to develop thunderstorms.
What is the primary difference between arctic and polar air masses?
Temperature
what is an airmass?
a large body of air that is uniform in temp and moisture content
Describe the structure of stationary fronts
boundary between two air masses, which does not advance towards either the warm or cold air.
Describe the characteristics of a cA air mass
cA= very cold and dry
Describe the structure of cold fronts
cold air advancing intro warmer air by cutting underneath the warm air, causing sharp lift, and clouds of vertical development.
describe the characteristics of a cP air mass
cold and dry
which air mass is associated with Lake Effect snow?
continental polar
describe the characteristics of an mP air mass
cool and moist
what clouds are associated with a cold front
cumuliform
describe the characteristics of a cT air mass
hot and dry
Of the five types of air masses, which are the hottest, driest, coldest, and most damp?
hottest= cT driest= cA and cP (cA has lower humidity) coldest= cA most damp= mT (but mP air would "feel" more damp)
Where are the primary air mass source regions in North America?
mP air =north Atlantic and north Pacific Ocean, mT air = Atlantic and Pacific oceans and Gulf of Mexico, cP air masses= northern USA and Canada, cA air masses= northern Canada and the arctic in winter, and cT air masses= desert southwest in summer
what airmass is responsible for the majority of precipitation in the midwest?
maritime tropical
Describe the structure of occluded fronts
occurs when a cold front catches up to a warm front and lifts the remaining warm air
What are the requirements for an area to serve as a source region?
source regions are found at high and low latitudes over large areas with similar characteristics of temperature and humidity.
what clouds are associated with a warm front?
stratiform
What is overrunning?
the process by which warm air is lifted up and over a cold air mass, producing precipitation
What do warm-type and cold-type occlusions both result in?
the warmer air being lifted up off the surface so that no discernable warm front exists.
Describe the structure of warm fronts
warm air advancing up and over cooler air, causing layered clouds
describe the characteristics of an mT air mass
warm and moist
What is the difference between warm-type and cold-type occlusions?
warm occlusions occur when the air behind the cold front is actually milder than the air the warm front is rising over. cold occlusions occur when a cold front overtakes a warm front, and the air behind the cold front is colder than the air over which the warm air is rising.
what is airmass modification?
what happens when an air mass moves away from its source region. it takes on the characteristics of the region it moves in to.
