Weather & Climate Test 3

Stable Air

resists change

unstable air

nudge it and it goes up (air rises)

Stable air is enhanced by: (1st factor)

Radiational cooling of the Earth's surface after sunset

Stable air is enhanced by: (2nd factor)

Cooling of air mass from below as it moves over a colder surface

Stable air is enhanced by: (3rd factor)

subsistence of an air column (sinking of air)

Unstable air is enhanced by: (1st factor)

Intense solar heating

Unstable air is enhanced by: (2nd factor)

Heating of an air mass below as it moves over a warmer surface.

Unstable air is enhanced by: (3rd factor)

forceful lifting of the air (mechanical lift) Ex: Fronts (The air around mountains)

Unstable air is enhanced by: (4th factor)

upward motion for surface air convergence

Unstable air is enhanced by: (5th factor)

Radiational cooling from nocturnal (night-time) thunderstorm cloud tops (very cold). Ex: over the plains

What do colder cloud tops mean?

instability

Dew

little droplets of water that have condensed upon objects usually near the ground when the temperature of those objects has cooled below the dew point temperature of the surrounding air. (in process of condensation). (NOT A FORM OF PRECIPITATION; important source of plants)

Frost

Covering of ice crystals produced by deposition (vapor to solid) (no liquid state) on exposed surfaces when (1) the air temperature falls to or below freezing or (2) when temp of object falls below the air temperature surrounding.

What are clouds a sign of?

Saturated atmosphere

Most clouds form as:

Air rises and expands and then cools

For condensations to occur 2 things must happen: (1)

Air must be saturated

For condensations to occur 2 things must happen: (2)

Must be a surface on which that moisture condenses upon.

Condensation Nuclei

Dust and salt

In real life clouds form (1)

Surface heating ("free" convection)

In real life clouds form (2)

Topographic lift

Topographic lift

Air rises because of mountains

In real life clouds form (3)

Widespread lifting (due to surface convergence)

In real life clouds form (4)

Uplift along fronts

dynamic/mechanical lift

Topographic lift, widespread lifting, uplift along fronts

Fogs

A cloud with its base on the ground

Radiation Fog

It forms overnight as the air near the ground (surface temp) cools and stabilizes. When this cooling causes the air to reach saturation (dew point temp), fog will form.

What is the most common fog for Austin?

Radiation Fog

What fog type develops with little wind (1,2,3 mph)?

Radiation Fog

Advection Fog

forms as warmer, moist air moves over a cold ground. The air is cooled to saturation by the cold from the ground below cooling the air above. Unlike radiation fog, advection fog may form under cloudy skies and with moderate to strong winds.

Where does Advection fog happen most often?

Most in west coast near colder ocean currents

Upwelling

bring cold water toward coast

Marine Layer

Clouds form over ocean (Ex. San Francisco)

Evaporation/Mixing fog:

Breathing out to colder air and seeing "fog".

Upslope fog

"clouds" in the uphills of mountains

1802

Cloud classification first considered

1803

English naturalist, Luke Howard, created a new cloud classification scheme. (The 4 latin roots)

What are the 4 latin roots developed by Luke Howard in 1803?

Stratus, cumulus, cirrus, nimbus/nimbo

Stratus

Layer

Cumulus

Heap/"Pile up". Tells about instability and this cloud could create a tornado

cirrus

curl of hair (think of horse's tail when running)

Nimus/Nimbo

"violent rain" (PRODUCES PRECIPITATION!)

How many of the 10 cloud types precipitate?

2; Nimbostratus and stratocumulus clouds

Vertical extent clouds

are from surface of Earth to top (20000')

How many cloud symbols are there?

12

Cloud obervation

Surface weather observations (METARs) estimate cloud coverage in "Octas" (Eighths of the sky)

CLR

Clear (0 octas in sky)

CB

cumulonimbus

1/8 and 2/8 octas

Few clouds

3/8 and 4/8 octas

scattered

5/8 and 6/8 and 7/8

Broken

8/8

overcast

Geostationary Satellites:

Don't move and take pictures all over the same area approximately 22500 miles in space.

Polar orbiting satellites

At lower levels; they orbit over the Earth and take pictures approximately 532 miles from Earth's surface

Visible satellite data

goes away at night

Infrared Satellite imagery

measures cloud top temp

What do cold cloud tops indicate?

thunderstorm

water vapor imagery

available 24/7 and best depicts mid and upper level of troposphere

What are the 2 precipitation formation processes?

Collision(Coalescence Process) and Bergeron(Ice Crystal Process)

What is a warmer temperature process, above freezing, and pure water?

Collision Process

What is found at or below freezing level, forms through deposition, and has no liquid state?

Bergeron process

Precipitation types:

Drizzle, Freezing rain, Ice pellets/sleet, Hail, Rain, Freezing Drizzle, Snow

Standard Rain Gauge

you do not want anything to be in the way. If you want to use a this way of measurement your device should be double the distance of nearest object.

Tipping Bucket Rain Gauge

A rain gauge that records rainfall by collecting rain in a chamber (bucket) that tips when the chamber fills with 0.01 in. (0.025 cm) of rain. Works well with light rain (inaccurate with heavy rain)

Trace of Rain

non measurable rain, but you know it rained.

How is snowfall measured?

Measured in 3 places and then average is found.

What is snowball measured in?

in tenths of an inch.

How much is 10 inches of snow equivalent to in water?

1 inch of water

Weighing Type Rain Gauge

Used mostly for aviation

What does colder snow mean?

less water because it is produced in a dryer atmosphere

What does warmer/wet snow mean?

More water is produced

Inches of snow to water (Wet snow)

5 in snow = 1 in water