Ch. 7

Question 1

source region

Answer 1

regions of earths surface that are particularly well suited to generate air masses. extensive, physically uniform, and associated with air that is stationary or anticyclonic. air masses are classified based on this region

Question 2

six general classes of air masses in N America

Answer 2

(1) Continental Polar (2) maritime polar (3) maritime tropical (4) Continental Tropical (5) Equatorial (6) Arctic/Antarctic

Question 3

Continental Polar

Answer 3

cP. central and northern canada. dominant feature in winter with cold, dry, stable nature

Question 4

Arctic

Answer 4

A. originate further north than the continental polar. colder and drier

Question 5

Maritime Polar

Answer 5

mP. air from pacific in winter can bring cloudiness and heave rain to mountainous coastal west regions. fog and low stratus clouds in the summer

Question 6

Maritime Tropical

Answer 6

air from Atlantic/Caribbean/Gulf of mexico is warm moist and unstable. influence weather east of rockies, southern canada and much of mexico serving as the principal precipitin source in this region

Question 7

Continental Tropical

Answer 7

relatively unimportant in north america. summer hot very dry unstable air surges into the southern great plaines area on occasion bringing heat waves and dry conditions

Question 8

equatorial

Answer 8

only affect n america in association with hurricanes, provides a ton of rain. high humidity and instability

Question 9

front

Answer 9

unlike air masses meet and do not readily mix. a narrow three dimensional transition zone

Question 10

cold front

Answer 10

advancing cold air mass meets and displaced a warm air front. lower portion of air slowed due to friction forming a nose at the front. steep. faster advancing. leads to rapid lifting and cooling of the warm air ahead of the cool air.

Question 11

warm front

Answer 11

gentle slope. when meets the cool air rises and cools adiabatically usually resulting in clouds and precipitation. clouds form slowly and turbulence is limited.

Question 12

stationary front

Answer 12

when neither air mass displaces the other. often gently rising warm air produces limited precipitation similar to that along a warm air front

Question 13

occluded front

Answer 13

when a cold front overtakes a warm front.

Question 14

midlatitude cyclones

Answer 14

dominate weather maps in the midlatitudes. associated with air mass convergence on regions between about 30 and 70 degrees of latitude. low pressure air, converging counter clockwise circulation.

Question 15

midlatitude anticyclone

Answer 15

extensive, migratory high pressure cell of the midlatitudes. generally bigger than cyclone and moves west to east with the westerlies. contain no fronts. air converging and moving down and diverging at surface, clockwise in N counter in S. winter: characterized by very low temps.

Question 16

tropical cyclones

Answer 16

intense, low pressure disturbances that develop in the tropic and occasional move poleward. hurricanes. form only over warm oceans in the tropics and at least a few degrees north or south of the equator. heavy damage and flooding.

Question 17

thunderstorm

Answer 17

defined as a violent convective storm accompanied by thunder and lightning. localized and short lived. vertical air motion, humidity, and instability. uplift must release enough latent heat of condensation to sustain the continued rise of air. high temp, high humidity, high instability

Question 18

tornado

Answer 18

one of the most destructive of all atmospheric disturbances. a deep low pressure cell surrounded by violently whirling air. most extreme pressure gradients. originate a few hundred meters above ground when the rotating vortex becomes a funnel.