Atmosphere Disturbance Pt 1 Flashcards
Air mass
parcel of air:
1) large
2) uniform in horizontal dimension
3) travels as unit
effect of Latitude on air mass
IF air mass forms OVER:
low-latitude air mass = warm/hot + unstable
high latitude = cool/cold more stable
over ocean = moist
over continental surface = dry
A Air mass
Arctic/Antarctic = A = formed over Antarctica, Artic Ocean, Greenland
Characteristics = very cold, very dry, very stable
cP air mass
Continental polar = cP = high latitude plains of Eurasia + North America (Canada area)
Properties = cold, dry, very stable
mP air mass
maritime polar = mp = oceans in vicinity of 50-60 N/S latitude
properties = cold, moist, relatively unstable
cT air mass
continental tropical = cT = low-latitude deserts
Properties = hot, very dry, unstable
mT
Maritime Tropical = mT = tropical and subtropical oceans
Properties = warm, moist, often unstable
Front
meeting point btwn unlike air masses
Cold vs Warm front
Cold front = ADVANCING cold air mass meets + displaces warmer air
Warm Front = ADVANCING warm air mass meets + displaces COLDER air
Symbols for fronts
Cold = blue, triangles
Warm = red, semi-circles
stationary = combo of cold + warm
occluded = purple, trianges + semi-circles all pointing up
Characteristics of cold fronts
cold fronts steeper, move faster –> easily displaces lighter, warm air
effect = rapid lifting + adiabatic cooling of warm air, forming blustery, violent weather along front
warm front characteristics
gentler slope –> results in less turbulent weather + slower frontal uplift
broad precipitation, can become violent
stationary front
when neither air mass displaces other, “Stall”
gently rising warm air produces limited precip, long last stationary front could cause flooding
generally w. mT, cP
occluded front characteristics
cold front overtakes warm front
winter –> occluded associated w. blizzards
generally stable conditions for most occluded fronts
Midlatitude cyclones
associated w. air mass movement btwn 30-70 degrees
midlatitude’s = meeting point of tropical + polar fronts - leads to lots of storms
Characteristics of midlatitude cyclones
1) cold front extending to SOUTHWEST
2) warm front extending to NORTHEAST
SECTORS:
cool sector to north + west
warm sector to south + East
Cold front trailing + warm front leading
Movement of midlatitude cyclone
1) travels along westerlies (ALL OF THEM GO TO EAST)
2) cyclonic wind circulation (Converges counterclockwise)
3) cold front moves faster than warm front
4) cold front moves south, warm front moves north
Birth (Cyclogenesis of midlatitude cyclone)
cyclones start of as rossby waves in jet stream, when winds become meridonal (moving north/south) instead of zonal (West to east) chance of cyclone increases
cyclones need convergence below + divergence above to form properly
what causes “death” of cyclone
Occlusion: eventually cold front overtakes warm front
as cold front catches up –> warm front is pushed further up until it is no longer in contact with earths surface –> occluded front formed
THIS means that short period of intensified precipitation + then low pressure center filled in, leaving the ground cooler + stable
How does midlatitude cyclone change weather
temperature = cold front passes dropping temperature abruptly
pressure = pressure decreases as cold front passes + then increases steadily
wind = winds come from south (bc of counterclockwise spin) + once passes, winds shift and come from west/northwest
clouds/precip = cloudiness + precip at front, then turned to clear as adiabatic cooling of warm air occurs
Midlatitude anticyclone
High pressure, moves west to esat bc of westerlies
diff between midlatitude anticyclone + midlatitude cyclone
cyclones = have fronts + anticyclones have no fronts
anticyclones stall over region for several days while cyclones generally do not
relationship btwn cyclones + anticyclones
1) generally alternate with one another
2) can occur independently BUT often have a functional relationship
**winds diverging from eastern part of anticyclone then go swooooooooosh into western side of cyclone (high to low pressure)
