Download Meteorology Notes

 Meteorology Weather vs Constantly changing .
Climate “average weather” 6 basic elements of weather/climate • temperature of air • humidity of air • type & amount of cloudiness • type & amount of precipitation • pressure exerted by air • speed & direction of wind .
Wind
Build a device that measures wind speed (25 pts)
What causes Wind?
Partial Answer:
Difference in air pressure
Air Movement (Horizontal – Advection)
Air moves from High Pressure to Low pressure
(just like osmosis in biology class)
Intensity (Speed) of the wind
Pressure – Gradient force
Gradient is like slope…
…the bigger the slope the faster the wind
Draw “isobars” on this map…
Draw air movement from High to Low pressure
What causes the difference in Air Pressure?
Answer:
Sun heating the Earth’s surface unevenly
The zones around the Equator receive more heat than the N-S Poles.
The Earth tries to balance out the uneven heating.
Warm air moves towards the Poles
Cold air moves towards the Equator.
The Sun does not heat the Earth evenly Winds are created SUMMARY…
(20 pts possible)
What causes Wind?
The SUN (1 pt)
Sun creates High & Low pressures which causes Wind (5 pts)
Sun heats the Earth’s surface unevenly which causes Wind (5 pts)
Sun heats the Earth’s surface unevenly which creates High &
Low Pressures zones which causes Wind (12 pts)
• Sun heats the Earth’s surface unevenly, and in order to balance
out (fix) the uneven heating, High and Low Pressure zones are
created which causes air particles to move (WIND) (20 pts)
•
•
•
•
Wind (in detail)
Warm air rises (LOW PRESSURE)
Air expands
Expansion has a cooling effect
Cool air holds less moisture and condensation occurs
(15 pts)
We will talk about the spin a bit later…
Global Vertical Air Cycles
Global Climates
Add in
SURFACE
(Horizontal)
Air Movement
Air comes down from
HIGH pressure zones
and spreads out…
Due to Earth’s spin…
Now add in
Coriolis Effect
(30 pts)
As latitude increases,
Earth’s rotation speed decreases,
Coriolis Effect increases
(Fast car moving into slow traffic)
(Slow car moving into fast traffic)
Northern Hemisphere – wind deflects to right
Southern Hemisphere – wind deflects to left
Wind is named after the direction
the wind is coming from.
(30 pts*)
Land disrupts the ideal flow of Air Movement
“Permanent” Highs and Lows
(15 pts)
Global Wind Patterns create
Global Water Currents (10 pts)
( 10 pts* and 15 pts*)
Back to spin direction of LOW and HIGH Pressure Cells
Convergence
Divergence
Divergence
Convergence
(15 pts*)
(15 pts*) Jet Stream
www.weather.com
Maps – Classic Maps – Outdoor Activities - Aviation
Ping Pong Ball Demo
Use Jet Stream to predict weather patterns (10 pts)
El Nino
(15 pts)
See El Nino PowerPoint Presentation for further
information
Weather Fronts
(20 pts)
See Weather Front PowerPoint Presentation for
further information.
See Textbook for diagrams of Thunderstorm
development.
2 Projects
Hurricane tracking
Storm Review
(50 pts)
(50 pts)
Clouds
Dew point around a “condensation nuclei”
See PowerPoint for Cloud types
Cirrus
Cirrostratus
Altostratus
Stratus
Nimbostratus
(25 pts)
Cirrocumulus
Altocumulus
Stratocumulus
Cumulus
Cumulonimbus
Lenticular
Mammatus
Fog
(5 pts)
Basically the same as clouds
Cooling Fog
Radiation fog
still muggy air reaches dew point
morning sun burns it off
Advection fog
wind moves warm air over cool surface
air reaches dew point
Upslope fog
air moves up mountain slope
Adiabatic cooling
reaches dew point
Evaporation Fog
Steam fog
cool air over warm water
water evaporates and reaches dew point
Frontal fog
Frontal wedging…
warm air is lifted over cold air
rain produced falls into colder air
rain evaporates – reaches dew point - fog
Dew
Condensation onto cold objects – dew point is reached
Frost
“frozen dew” deposition (vapor to ice)
Types of Precipitation
(10 pts)
Cloud droplets are ¼ the thickness of human hair
Droplets may evaporate or coalesce into larger droplets
Rain
Cloud droplets that are large enough to fall
Drizzle
long lasting - smaller drops
produced by stratus or nimbostratus clouds
Mist
even smaller drops - barely hits ground - appears to float
Virga
rain falling and evaporating in drier air below
Snow
rain that turns into ice crystals
Sleet
ice crystals that travel from freezing temperatures thru
sub-freezing zone
Freezing Rain
Rain that hits the ground and freezes on impact
Hail
Rain – Ice - cycles up/down in cumulonimbus gaining size
Temperature
Isotherms
(“iso” = equal) (“therm” = temperature)
complete isotherm map activity
(25 pts)
Temperature Gradient
Temperature difference / distance
Factors that Control Temperature
Reminder…
The Sun does not heat the Earth evenly
(20 pts)
• It is the uneven heating that drives the ocean currents
and causes winds.
• Unequal heating transports heat from Equator to Poles.
Land vs. Water
Water absorbs heat slower than land
(water is harder to heat up)
Water loses heat slower than land
(water is harder to cool down)
Sunlight can heat water up to 200-600 meters in depth
Sunlight can heat land up to 15 meters in depth
RESULT:
places near water have a more stable
temperature
Warmest and Coldest temperatures are over land
Southern Hemisphere has fewer storms and more
stable climates
Water also undergoes more evaporation than land
(grass field vs. city)
Map Differences (be careful)
Ocean Currents
Responsible for ¼ of the heat transfer on Earth
to balance the heat budget
Convection Cycles
Warm currents move towards the Poles
Cold currents move towards the Equator
(St Johns Newfoundland 420 vs. London 510)
(Virginia Beach VA 610 vs. Carmel CA 560)
Lower Mean Temp
Higher Mean Temp
Geographic location
Windward Coast
Carmel CA
Windward
Smaller Range of Temps
Windward
Ocean to Land breeze
cool summers
mild winters
vs.
vs.
Leeward Coast
Virginia Beach VA
Leeward
Larger Range of Temps
Leeward
Land to Ocean breeze
warmer summers
cooler winters
Mountains also act as barrier
Spokane (inland) vs. Seattle (coastal)
Mountains minimize Windward effect
Windward – small range
Few miles inland
Latitude
It gets colder the further north you go
Isotherms (generally) go West to East
(lower mean as latitude increase)
Altitude
Temp decreases
10O per mile of altitude
6.5O per km of altitude
Less atmosphere (less absorption of sun’s energy)
on mountain tops so they have warmer days and
cooler nights
(lower mean and larger range)
Cloud Cover (Albedo)
Up to 50% of Earth is covered with clouds at anytime
(Albedo of 25% - 80%)
Day – cooling effect (reflect/absorb incoming energy)
Night – warming effect (reflect back to Earth
outgoing energy)
Snow and Ice have high albedos
3 largest factors that impact Temperature
(5 pts)
(1) Latitude
(2) Water
Windward Coast vs. Leeward Coast
Ocean Currents
(3) Cloud Cover (Albedo)
Example of impact of water… lake effect
Temperature Cycles (LAG)
(5 pts)
Daily Cycle
Sun’s intensity greatest around noon
…but temps at max between 2 and 5
(re-radiation of energy from Earth’s surface)
Annual Cycle
Summer Solstice (June 21-23) experiences
greatest solar radiation
…but July or August are the warmest months
Fahrenheit, Celsius, Kelvin
(10 pts)
(5 pts)
Wind Chill
Actual Temperature on skin vs. Temperature feel on skin
Moisture in Atmosphere
Water Vapor makes up less than 5% of atmosphere…
… but it is the MOST IMPORTANT Gas in atmosphere
97.2% Oceans – Saltwater 2.8% Freshwater 2.15% Ice .65% is liquid Lakes/streams/air Groundwater Latent Heat
(see next page)
… hidden or dormant
(20 pts)
…this is what causes storms
Evaporation
(cooling)
Saturation (full)
Hydrological (Water) Cycle
(10 pts)
Powered by the SUN
Condensation
Evaporation Transpiration Sublimation
Runoff
Precipitation
Plant Uptake
Sublimation
Melting
Solid
80
Evaporation
Liquid
Freezing
600
Condensation
Deposition
Gas
Absolute Humidity
Amount of water in cubic meter of air
Heat does not change this
As temperature increases…
…more water is added but volume also increases
so Absolute Humidity stays the same
Relative Humidity
Amount of water
in a cubic meter
of air
vs.
“percentage of what air can hold”
“Relative to what is possible”
The amount of water
the air can hold without
precipitation occurring
Relative Humidity changes when…
…Temp goes up/down
…Add/Subtract water
Dew Point (100% Rel. Humidity)
…Temperature at which air is saturated
Experiment to determine Relative Humidity
(20 pts)
-­‐4 14 23 32 41 50 59 68 77 86 95 104 113 122 (degrees F ) (15 pts)
Pressure Volume Temperature…
Expansion of Air has a cooling effect
…Cans of compressed air
…Air compressor
Expansion is adiabatic expansion
Air expands (and cools) as it rises into thinner air
Summary:
Hot air rises
Upper Atmosphere is thinner so less pressure
Air Expands due to less pressure
Air cools
Cool air holds less moisture
Condensation forms (clouds)
Reach Dew Point (precipitation)
Adiabatic Rate
(10 pts)
Before Condensation (Dry Adiabatic Rate)
100 per km
After Condensation begins (Wet Adiabatic Rate)
50 per km
Atmospheric Stability:
If air rises slower than Wet Adiabatic Rate (50/km)
- Air is cooler than surrounding air
Environmental Lapse Rate < the Wet Adiabatic Rate
Temperature Inversion (very stable – no mixing)
“Brown Cloud”
Atmospheric Instability:
If air rises faster than Dry Adiabatic Rate (100/km)
- Air is warmer than surrounding air
- Warm air carries lots of moisture
- Storms
Environmental Lapse Rate > the Dry Adiabatic Rate
Unstable air produces towering clouds with heavy rain
Conditional Instability
Environmental Lapse Rate is between the
Wet & Dry Adiabatic Rates.
The air is stable with unsaturated air,
but unstable with saturated air.
Dreary, overcast day with light drizzle
100 km 90 km 80 km 70 km 60 km 50 km 40 km 30 km 20 km 10 km 0 km extremely cold Height/Structure of Atmosphere (5 pts) (Ionosphere) Thermosphere 100 km 90 km 80 km 70 km Mesosphere 60 km 50 km (Ozone Layer) 40 km Stratosphere 30 km 20 km Troposphere 0o hot really hot Temperature 10 km 0 km Exosphere (above 800 km) 0 100 500 1000 Pressure (mb) Atmosphere Composition / Ozone Layer (pgs. 6-­‐9) (5 pts) Homosphere 0-­‐80 km uniform distribution vs Heterosphere above 80 km varies by mass of molecule N2 O He H Ionosphere located in the Thermosphere/Heterosphere N2 O ionize due to absorbing high-­‐energy solar energy lose electrons and become +charged ions electrons are free to move Solar flares release lots of solar energy (charged particles) The charged particles mix with Earth’s magnetic field Charged particles are guided toward N-­‐S magnetic poles Charged particles mix with ionosphere and cause Auroras (5 pts) Electromagnetic Spectrum (10 pts) Seasons are due to angle of sun’s rays. (flashlight demo) (10 pts) Equal 12 hr. day & 12 hr. night Vernal Equinox March 21-­‐23 Fa
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Heat The total kinetic energy of all the molecules. Units of measurement: calories, joules Temperature (Hot): The average kinetic energy of all of the molecules. Units of measurement Degrees Which is hotter and which has more heat … a lit match or a swimming pool w/80° water? Heat moves from a high temperature object to a low temperature object. (Hot to cold.) (5 pts) Ultraviolet and Visible Energy 19% absorbed by atmosphere and clouds 51% absorbed by Earth and Water 30% albedo -­‐ reflected back to space Infrared Energy (heat) Longer wavelength Nitrogen (N2) (78%) does not absorb much infrared energy Oxygen (O2) (21%) does not absorb much infrared energy Argon (Ar) (0.9%) does not absorb much infrared energy Carbon Dioxide (CO2) (0.04%) absorbs infrared energy CO2 levels are increasing so heat is increasing Water Vapor (varies around 1%) absorbs infrared energy Cloudy nights are warmer Clear nights are cooler (5 pts) Heat Transfer Conduction Convection (5 pts) Increase in K.E. of molecules in metal (solids) - molecules bump into each other Air (trapped air) makes good insulation Movement of heat thru liquids (air is a liquid) - Warm air rises (thermals) with moisture - Cool air sinks Convection is important in our atmosphere Advection – horizontal movement of heat Radiation Carried by electromagnetic waves (not molecules). See page 31 figure 2-­‐8. See electromagnetic radiation spectrum. Laws of Radiation: 1. 2. 3. 4. All objects, at whatever temperature, emit radiation. Hotter objects radiate more total energy/unit area than cold ones. The hotter the body, the shorter the λ of radiation. Objects that are good absorbers are good emitters. Black Body Snow reflects 90% of visible light from above, but absorbs and emits IR from the Earth. That is why the air above the snow is cold. Snow reflects Earth's IR down which keeps things warm under a blanket of snow thus preventing or minimizing frost layers. "Blanketed with snow? P. 35. (5 pts) Sunsets are reddish because the longer red wavelengths do not scatter due to their long wavelengths whereas the shorter blue wavelengths do scatter. Crepuscular rays are when bands of light scattered through large particles in the atmosphere, like clouds. We see these when sunlight shines through clouds. Please see figure 2-­‐14, page 38. FYI…Easter is the first Sunday after the first full Moon after the Vernal Equinox.