Quiz 4

Question 1

air mass

Answer 1

large body with similar characteristics (T, moisture)

Question 2

c, m, T, P, A, k, w

Answer 2

continental, marine, tropical, polar, arctic, unstable, stable

Question 3

front

Answer 3

boundary between two air masses

named for one moving forward

Question 4

signs of a cold front (5)

Answer 4

pressure drop at front (rising air)
decrease in dew point
drop in temp
shift in wind direction
cloud formation/precipitation

Question 5

Cold front associated clouds (4)

Answer 5

cumulonimbus
cirrus
cirrostratus
altocumulus

Question 6

signs of a warm front (5)

Answer 6

pressure drop at front (rising air)
increase in dew point
increase in temp
shift in wind direction
little precip

Question 7

warm front associated clouds (5)

Answer 7

stratus
nimbostratus
altostratus
cirrostratus
cirrus

Question 8

occluded front

Answer 8

cold front catches up to and overtakes a warm front; cold and warm type

Question 9

3 stages of wave cyclone growth

Answer 9

cyclogenesis, open wave, advanced occlusion

Question 10

cyclogenesis

Answer 10

high wind shear
circulation along stationary front
low pressure center forms at center of vortex

Question 11

open wave

Answer 11

becomes mature when initial point of occlusion is reached

storm most intense at initial occlusion

Question 12

advanced occlusion

Answer 12

cold front almost fully caught up to warm front

at triple point, secondary low pressure center forms

Question 13

what does a midlatitude cyclone need to intensify?

Answer 13

must be an upper level trough (L) to the west of the surface low = divergence of air above surf low, strengthening system

Question 14

baroclinic instability

Answer 14

positive feedback cycles that strengthen cyclone

Question 15

baroclinic atmosphere

Answer 15

isotherms cross isobars
upper level wave will intensify
cold advection to the west will enhance sinking of air, intensifying surf H
warm advection to the east will cause rising air, causing surf L

Question 16

barotropic atmosphere

Answer 16

isotherms parallel to isobars

no temp advection occurs

Question 17

ordinary vs severe Tstorms

Answer 17

ordinary: vertical updrafts
severe: slanted updrafts

Question 18

ordinary tstorms

Answer 18

most common

form in regions of low wind shear

Question 19

stages of ordinary Tstorm formation (3)

Answer 19

cumulus, mature, decaying

Question 20

Cumulus stage (ord tstorms)

Answer 20

updrafts dominate
water condenses
latent heat is released

Question 21

mature stage (ord tstorms)

Answer 21

appearance of downdraft
updrafts/downdrafts are vertical
gust front enhances updraft
strongest stage

Question 22

decaying stage (ordinary tstorms)

Answer 22

dominated by downdrafts

cuts off moisture source

Question 23

severe thunderstorms

Answer 23

vertical wind shear results in slanted updrafts and downdrafts
storms usually extend to tropopause

Question 24

supercell thunderstorm

Answer 24

updrafts are rotating

very high wind shear creates horizontal rotation, twisted into the vertical by updrafts

Question 25

squall line

Answer 25

Tstorms that form in front of a cold front

Question 26

tornado formation steps (5)

Answer 26

1. high wind shear causes layer of air to roll (vortex tube)
2. updrafts lift vortex tube into vertical orientation
3. CCW cyclone survives, forming mesocyclone
4. downdrafts in front and rear force air into mesocyclone, then air accelerates as moves closer (conserve ang mom)
5. fast spinning air rises and diverges aloft, intensifying surf L –> increases surf convergence == positive feedback intensifies tornado

Question 27

lightning: charge separation (4)

Answer 27

hail collides with supercool liquid drops, drops freeze, releasing latent heat
warm hail collides with cold ice crystal, net transfer of + charge to crystal
+ ice crystals to top of storm, negative hail falls to bottom
also occurs when hailstorms are fragmented (smaller fragments carry + charge)

Question 28

lightning: electric potential

Answer 28

normally, earth has net negative charge compared to atmosphere (120V/m)
charge separation induces much greater positive charge on ground (200000V/m)

Question 29

lightning strike! (3.5)

Answer 29

1. stepped leader: negative charge at base of cloud moves toward ground through air
2. positive charges move upward to meet negative charge when close enough
3. flash occurs when two streams meet, flow of positive ions is carried to cloud on return stroke

can be several pairs of strokes, returns per flash