Envs, Geol, Phys 112: Global Climate Exam 1 Review

Energy-Atmosphere System Review Aguado & Bert: Ch. 1, 2, 3, 4, 5, 6, 7

Location on Earth (L03) Latitude & Longitude great circles, prime meridian, time zones, cardinal points, azimuth know the named latitudes numerical latitude (what’s at 23.5°?) why each warrants a name! The Atmosphere (AB7 pp. 10-24, L02) Structure Thermal structure Troposphere & Stratosphere Composition Primarily N2 (78%), O2 (21%), Differs from Mars, Venus Evolution of composition Oceans absorbed CO2, locked it into rocks Life generated and maintains oxygen levels

Temperature decreases

with altitude

Stromatolites in Shark Bay, Australia

Temperature increases

with altitude

Troposphere = Sphere of change = Sphere of weather Temperature decreases with altitude (heated by ground) Stratosphere = Sphere of layers … primarily the ozone layer Temperature increases with altitude (heated by ozone layer absorbing UV)

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Sun and Earth (AB7 Ch. 2, L03) Energy from the Sun Light = Shortwave Radiation from Sun Seasons (AB7 pp. 42-50, L04) Equinoxes & Solstices Named latitudes Equator, Tropics, Arctic & Antarctic Circles What latitudes? How are they defined? Energy Balance & Temperatures (Ch. 3, L13) Insolation (AB7 pp. 56-60, L04 & 05 ) Reflection Albedo: Earth ~ 31 Scattering Blue sky & Daylight Blue light is scattered … makes sky blue Red goes straight … setting sun looks red Absorption by atmosphere Absorbs most IR, almost all UV, X-ray Absorption & Re-radiation by surface (Greenhouse) Absorbs shortwave (visible), radiates longwave (IR) Atmospheric Moisture (Ch. 5)

Weather! Greenhouse

effect Ground absorbs 45% of solar energy

Atmosphere absorbs 21% of

solar energy

Ozone absorbs 3%

of solar energy

Earth reflects 31% of solar energy

Earth re-radiates 69% of solar energy

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mass of water vapor (g)mass of air (kg)

=

Specific HumidityMaximum at Current Temp.

=

( )( )Dry Air 3C

kgPressure (Pa)m287 T 273

=+

ρ amount of water stays the same, amount air can hold changes

Water on Earth (AB7 Ch. 5, L12) 71% of surface area: Pacific Ocean and Southern Hemisphere 97% Oceans 3% Freshwater Properties: Polar Molecule (Mickey Mouse) Creates surface tension Makes solid float in liquid Creates hexagonal crystals: Pencil slices create halos, sun dogs, sun pillars, etc. High Heat Capacity: Energy transfer to change temperature Energy to heat 1 kg 1 C° = Energy to lift 1 kg ¼ mile! High Latent Heat: Energy transfer to change phase Energy to melt 1 kg of ice to water (at 0°C) = Energy to lift 1 kg 20.7 miles! ⇒ Understand “Stone Soup” & “Fire & Ice”! Water Vapor Content (AB7 pp. 126-135) Psychrometric Charts! (L04) Specific Humidity Relative Humidity (% of moisture air can hold) Air Density (dry air) Moisture Content

Positive side where electrons rarely hang out

Negative side where electrons mostly hang out

3 3 3

kg Dry Airkg Dry Air m Dry Air m Dry Air m Dry Air

g water g water m water____ ____

× = =

Review the “Measuring Humidity” worksheet!

Energy Transfer and Temperature Heat Capacity: Energy required to raise (or lower) the temperature of a substance Latent heat: Heat released or absorbed when something (water) changes state released: gas to liquid (condensation), liquid to solid (freezing) absorbed: solid to liquid (melting) or liquid to gas (evaporating) Heat transfer Conduction: Hot stuff heats neighbors (inefficient!) Convection: Hot stuff moves Radiation: Heat (energy), itself moves (as IR)

amount of water present in air

% of water air can hold

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Atmospheric Pressure and Winds (AB7 Ch. 4) ATMOSPHERIC PRESSURE Pressure -- weight of column of air (1 hPa = 10 Newtons/meter2 = 1 mb) Sea-Level Pressure Standard = 1,013 hPa = 29.92 inHg WIND (AB7 PP. 105-116 L05 & 06) Air is Moved by Forces Pressure Gradient Force (FPG) F = ∆P/d ∆P is the change in pressure over distance d Coriolis Force (FC) Only deflects MOVING air … goes away in still (or very slow) air Friction Friction with Earth's surface slows wind No friction aloft Geostrophic Winds (aloft) occur when FPG = FC parallel to isobars Clockwise around highs in N. Hemisphere Counterclockwise around lows in N. Hemisphere Non-Geostrophic Winds (surface) occur when FPG ≠ FC force because due to wind friction with surface inward to low, outward from high Lifting (AB7 pp. 162-164, L07) Forced orographic (over mountains) Where does this happen? What’s the result? frontal (know characteristic weather on last page) convergent lifting convectional lifting

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a) Stationary Front

b) Cyclone begins with wave c) Mature Cyclone … cold front chasing warm front

Air Masses and Fronts (AB7 pp. 264-282, L11) Air Masses Large volumes of air Move and collide Fronts form at collision zones Most weather takes place at fronts Dry lines separate air masses of same temperature but different humidities (e.g. cT & mT) Mid-Latitude Cyclones (AB7 pp. 290-293, L11) Stationary front where warm and cold air masses push on each other Instability forces a wave to start, then rotation follows Cold front moves faster than warm front Cold front overtakes warm, pushes warm air aloft ⇒ Occluded front! Inversion remains after dissipation of occlusion

1. Cold 2. Warm 3. Stationary 4. Occluded 5. Trough 6. Squall Line 7. Dry Line

d) Occlusion begins e) Mature Occlusion: warm air aloft (inversion)

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Fronts (AB7 pp. 264-282, L11) … what air masses are involved? Weather associated with a cold front:

Weather Phenomenon Before Front Passage Contact with Front After Front Passage

Temperature Warm Sudden Cooling Cold & Getting Colder

Pressure Steady Decrease Level then Increasing Steady Increase

Precipitation Showers Heavy Precip., T-Storms Showers then Clearing

Weather associated with a warm front:

Weather Phenomenon Before Front Passage Contact with Front After Front Passage

Temperature Cool Sudden Warming Warmer then Leveling

Pressure Steady Decrease Level Slight Rise Then Decrease

Precipitation Showers, snow, sleet

or drizzle Drizzle or Rain None

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Atmospheric Stability (AB7 Ch. 6, L14) 1) Lapse Rates a) Environmental lapse rate (ELR) -environment’s change in temperature with height b) Dry adiabatic lapse rate (DAR) - change in temperature with height of a dry parcel of air - dry parcels cool more quickly than moist parcels c) Moist adiabatic lapse rate (MAR) - change in temperature with height of a parcel in which water is condensing - moist parcels heated by latent heat & have higher heat capacity ⇒ cool more slowly than dry 2) Atmospheric Stability (AB7 pp. 165-174, L14) a) Stable conditions: parcel always cooler than environment - environmental lapse rate steeper (slower) than adiabatic rates b) Unstable conditions: parcel always warmer than environment - environmental lapse rate less steep (faster) than adiabatic rates c) Conditionally stable conditions: - dry air cools faster than surroundings, - moist air cools more slowly than surroundings