Cirrus clouds
- high level
- thin and wispy
- compose of ice crystals originating from the freezing of supercooled water droplets
alto cumulus cloud
- mid-level
- parallel bands (top) / rounded masses (bot)
- form by convection in an unstable layer aloft
fair weather cumulus
- lifetime of 5-40min
- flat bases and distinct outline
nimbostratus
- dark, low level
- composed of water droplets cuz theyre low
When is hail formed?
when updrafts in thunderclouds carry raindrops upward into extremely cold areas of atmosphere
Atmosphere levels
What gases are contained in dry air (atmosphere)? name top 3
Stratosphere (upper)
—tropopause (separates the two)—–
troposphere (lower)
-in order, nitrogen, oxygen, argon
Why do polar regions receieve much less solar energy than equatorial regions?
B/c energy from the sun has smaller surface area on equator than the polar regions b/c of the sphere shape of earth,
energy = radiation / surface area, less surface area means more energy (equator)
What is atmospheric circulation a function of? (What is wind a function of)
function of coriolis force, pressure and temperature gradient, and earths angular momentum
Difference between actual lapse rate and dry adiabatic lapse rate?
Dry adiabatic lapse rate is when the air is unsaturated (no water) and thus the dry lapse rate is much lower because there isnt gas h20 that releases energy when it goes from gas to liquid (latent heat)
How does precipitation / condensation happen?
- As we ascend in our atmosphere, air temp decreases (lapse rate)
- as temp goes down, an air parcel not saturated with water vapor may become saturated at dew point temp (Td)
- so unsaturated air goes up, becomes saturated, which triggers condensation, then formation of water droplets (ice particles), then rain drops or snow flakes which are heavy enough to descend (precipitation)
Requisites for precipitation?
- Creation of saturation conditions
- Phase change of water content (vapor to liquid/solid)
- Growth (small water droplets or ice crystals to precipitatable size)
3 Basic precipitation mechanisms (causes of precitipitation)
- Stratiform (cyclonic cooling)
- induced by circulation - Convective
- induced by mechanical lifting over mountain barriers - Orographic
- induced by vertical instability of moist air due to surface heating
What are 2 fronts? define them
Stratiform (mechanism of precipitation induced by circulation)
- Cold front
- cold air advances —–>
- lifts warm air upward very fast ^^^^^
- front is almost vertical
- moisture condenses to produce the clouds and heavy precipitation - warm air glides over cold air with slow lifting, producing light to moderate precipitation
3 Stages of midlatitude Thunderstorms.
what are they driven by?
Dominated by convection mechanisms in 3 stages
1) warm moist air is drawn into cell
2) lifted to middle region where precipitation forms
3) flow out of cell in upper atmosphere as cool, dry air
cycle repeats itself, driven by latent heat released during condensation
how do extratropical cyclones form
- initial parallel warm and cold air masses become coupled and whirled together in circular motion, creating giant spiral centered on a low pressure zone (cyclone)
- anti clockwise in northern hemisphere
How/where are hurricanes produced?
- in low latitude regions when ocean surface is warmest, intense storms (hurricanes) can be produced out of warm ocean surface and low pressure center
- wind moving inward from all directions towards the storm “eye” spiraling, picking up moisture from the evaporating ocean surface, forcing warm air mass to rise, creating clusters of thunderstorms, which release large amount of rain and latent heat
Orographic storms
- when warm moist air forced to rise over, say, a mountain, condenses and form precipitation
- windward slope has more rain
- leeward slope has less rain
When does the dry adiabatic lapse rate start?
tropopause
Dew point temp
-X amount of water vapor will become saturated if air temp drops from actual air temp to the dew point temp (thats when condensation occurs)
Why is the wet bulb temp lower than the dry bulb temp?
-alchohol on the wet bulb evaporates which cools down the wet bulb
Wet-bulb depression?
=Tdry - Twet
Define meteorology
study of the atmosphere with particular emphasis in weather and climate
define weather and climate
weather = condition of atmosphere at a particular time climate = average condition of the atmosphere during a period (weeks, yrs, decades....)
Greenhouse effects?
CO2, water vapor and CFC gases trap solar energy
