Met Flashcards
what is most valuable for telling weather
water vapour
atmospheric divisions
- troposphere
- stratosphere
- mesosphere
- thermosphere
standard
15 degrees C
29.92” Hg
lapse rate of 2 degrees per 1,000ft
veer vs. back
veer = wind changes clockwise
back = wind changes counterclockwise
dew point
temp. air must be cooled at at constant pressure to be saturated (at that temp. fog and clouds occur)
relative humidity
moisture in air vs. maximum at given temp.
(air heated = relative humidity increases)
(closer dew point spread = higher)
high clouds
ice crystals, no precip.
cirrus, cirrocumulus, cirrostratus (approaching warm front)
Low level clouds
stratus, stratocumulus, nimbostratus (continuous rain)
vertical development
cumulus, towering cumulus, cumulonimbus (thunder and lightning)
atmosphere pressure
told with altimeter
pressure from weight of overlying air
where is lowest pressure in low pressure system
centre
how does air flow in low pressure system
inward and rises
counter-clockwise
what kind of weather does a low pressure system bring
bad-lots of clouds
unstable
how does air flow in high pressure system
sinks and flows outward
clockwise
what weather does high pressure system bring
good-few clouds
stable
coriolis force
pressure gradient force moves air from high to low
influenced by rotation of earth
what does wind do on climb out
increase and veer
what does wind do on descent
slows and backs
what is a sea breeze
pnshore flow from rising heated air over land during day
land breeze
offshore flow from cooling air over land flowing to sea at night
mountain wind
peaks and valleys cause uneven heating
anabatic = upslope from daytime heating
catabatic = downslope from heavy air cooling
mountain waves
airflow smooth up front, turbulent down back (wind shear and increased speed)
squall
gust longer than 1 minute
wind shear
sudden, drastic speed/direction change over small area
why does atmosphere heat/cool
angle of sun hitting earth
solar radiation
terrestrial radiation
convection
air moving from warm to cold (hot surface air rising)
advection
air from cold flowing over warm 9heated by earth in bottom layers)
turbulent mixing
mechanical mixing from ground friction
compression
large section subsides (higher pressure = higher temp.)
stages of thunderstorm
- cumulus - hot air rising (updrafts)
- cumulonimbus fully developed (up + down drafts, anvil top, rain, gust front, wind shear, hail)
- tail end - downdrafts, less rain, strong wind burst
icing
supercooled droplets on wings
rime ice
milky, skin less that 0 degrees, leading edge
clear ice
adds weight, larger supercooled drops, most dense
frost
subzero surface and moist air (destroys lift)
connective / thermal turbulence
sun heats ground, air rises
mechanical turbulence
air over topographical features
radiation fog
ground cools rapidly, surrounding air reaches dew point
advection fog
warm air over cold ground (coastal)
upslope fog
moist stable air forced up mountain
steam fog
cold air over warm water
ice fog
moist air during extremely cold, calm conditions
