Transcript Water and Clouds

Water and Clouds
GPH 111
Water and Clouds
 Water Basics
 What makes an air mass rain?
 Air mass instability
Water Basics
 Where water came from...
 Earth’s water breakdown
 Water’s phase changes and latent heat
 Humidity and Relative Humidity
Where did
the water
come from?
Water on Earth…
Covers 71% of
earth and makes
up 70% of your
body…
Earth’s water breakdown…
Water
Phase
Changes
Snowflakes,
Icebergs,
and Frost
Latent Heat and Phase Changes
Released
WATER
moderate
540 calories
slow
85 calories
ICE
Absorbed
WATER VAPOR
fast
Humidity and Relative Humidity
actual water vapor content of the air
Relative =
X 100
maximum water vapor capacity of the air
Humidity
Dew Point Temperature = The temperature at which an air
mass cools to reach 100% relative humidity or saturation.
Relative
humidity
throughout
the day…
Why is there water on the
outside of a cold glass of water?
How much
water does
AIR hold?
Relative
Humidity
Dew
Point
What makes an air mass rain?
 Forces on an air mass
 Dry and Wet adiabatic lapse rates
 Forming clouds and cloud types
 Four lifting mechanisms
 Orographic exercise
 Frontal exercise
Forces on an air mass…
Buoyancy Force - causes air masses to ascend
Gravity Force - causes air masses to descend
Back to Adiabatic Lapse Rates…
Back to Adiabatic Lapse Rates…
Back to Adiabatic Lapse Rates…
Unstable - When an air
mass is or becomes
warmer compared to the
surrounding atmosphere
(like when latent heat is
released after air is
saturated)
Stable - When an air
mass is or becomes cooler
compared to the
surrounding atmosphere
Cloud Formation and Cloud Types:
Why are the
bottom of
clouds flat?
Remember, an air mass needs to
cool in order to generate rain!!!
Cloud Formation and Cloud Types:
How about
“Blood”
Rains!
Four Lifting Mechanisms…
ways to cool off air masses to generate rain
 Convergent - Air flows towards low pressure
(like the tropics)
 Convectional - Heating over the continent
causes lifting on an air mass
 Orographic - Air rises upslope as it pushes
against a mountain (rain shadow)
 Frontal - Places of atmospheric discontinuity
generate locations of lifting (Cold and Warm
Fronts)
Four Lifting Mechanisms…
Convergent
air lifts
through
convergence
at the
equator
Convectional
air lifts
through
heating
Show
Florida
Movie!
Orographic
air lifts by being forced to rise
over an obstruction
Orographic
Orographic Exercise
Frontal (Air Masses)
Frontal
Warm air
lifts by
running
over cold
air
Frontal (Cyclogenesis)
Frontal (Cold Front)
Frontal (Warm Front)
Frontal (Midlatitude Cyclone)
http://apdl.kcc.hawaii.edu/~earth/front.htm
Frontal Exercise
Barometric Pressure: If first digit is > 5, add a 9 in front
If first digit is < or = 5, add 10 in front
Frontal Exercise
Day 1
Day 2
Day 3
Frontal
Exercise
Air Mass Instability
 Thunderstorms and Lightning
 Tornadoes
 Hurricanes
Global Circulation Instability
 El Niño and the Southern Oscillation
Thunderstorms
Thunderstorms
Common Thunderstorms
Repeatedly forming and dying, not very powerful
Common Thunderstorms
Squall Line Thunderstorms
Worst First Storms – Can be powerful
Squall Line Thunderstorms
Arizona October 6th, 2010
Supercell Thunderstorms
The SUPER bad – Worst Second Storms
Supercell Thunderstorms
The SUPER bad – Worst Second Storms
Supercell Thunderstorms
Tornadoes
1. Warm and Humid air at the surface
2. Cold and Dry air aloft
3. Winds moving faster aloft or at a different
direction than at the surface (wind shear)
Tornadoes
Tornado – F5
Fish Falls / Frog Falls
Tornado Track
Tornado Damage
Lightning
Heats air
to 54,000
degrees F
Five times
hotter
than the
surface of
the sun!!!
Falling raindrops
concentrate
mostly negative
charged
particles along
the cloud’s
base, which
react to positive
charged
particles on the
ground
Lightning
Lightning
Thunder
Caused by the rapid
expansion and ionization of
air by the tremendous heat
generated from a lightning
strike, and can not occur
without lightning.
The rapid heating and
ionization generates a
shock wave similar to a
sonic boom associated with
a super sonic aircraft.
http://www.partnersinrhyme.com/soundfx/Weather.shtml
Hurricanes and Typhoons
1) Uniform winds (no wind shear)
2) Away from the eqautor (need geostrophic winds)
3) Warm water (the fuel for a hurricane)
Hurricanes and Typhoons
http://www.youtube.com/watch?v=FxgNuD5M9js
http://www.youtube.com/watch?v=H9VpwmtnOZc
http://www.youtube.com/watch?v=XTvkrLESrwU&feature=fvwrel
http://www.youtube.com/watch?v=tVoMtPFtEg0&feature=related
Hurricanes and Typhoons
Katrina – 215 mph, 902 mb, 30 ft
Rita – 200 mph, 898 mb, 20 ft.
Hurricane
Katrina
Hurricane
Rita
Hurricane Katrina Damage
Atlantic Hurricanes
El Niño and the Southern Oscillation
La Nina – Cool water in the eastern Pacific, warm in western Pacific
El Nino – Warm water in the eastern Pacific, cool in western Pacific
El Niño and the Southern Oscillation
Show Movie!!!
Things to Know:
 Sources of water on earth and general geographic
breakdown
 Water phase changes and latent heat energy
transfer
 Relative humidity, general breakdown throughout the
day
 Buoyancy and gravitational forces on air masses
 Dry and wet adiabatic lapse rates
 Four lifting mechanisms - convergent, convectional,
orographic (know the math), and frontal
 Cold fronts, warm fronts, and dominant air
masses
 Two parts of a Thunderstorms, Three types of
thunderstorms, how lightning works, conditions
necessary for tornadoes and hurricanes, and how
ENSO works.
Help: Chapter AM