Envs, Geol, Phys 112: Global Climate. Energy-Atmosphere System Review Aguado & Bert, Ch. 1, 2, 3, 4, 5, 6, 9, 10

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1 Exam 1 Review Energy-Atmosphere System Review Aguado & Bert, Ch. 1, 2, 3, 4, 5, 6, 9, 10 Location on Earth (L04) 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 , L04) Structure Thermal structure Troposphere & Stratosphere Composition Primarily N 2 (78%), O 2 (21%), Differs from Mars, Venus Evolution of composition Oceans absorbed CO 2, locked it into rocks Life generated and maintains oxygen levels Stromatolites in Shark Bay, Australia Temperature increases with altitude Temperature decreases 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)

2 Sun and Earth (AB7 Ch. 2, L04) Energy from the Sun Light = Shortwave Radiation from Sun Seasons (AB7 pp , L04) Equinoxes & Solstices Named latitudes Equator, Tropics, Arctic & Antarctic Circles What latitudes? How are they defined? Energy Balance & Temperatures (Ch. 3, L14) Insolation (AB7 pp , 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) Earth reflects 31% of solar energy Earth re-radiates 69% of solar energy Ozone absorbs 3% of solar energy Atmosphere absorbs 21% of solar energy Atmospheric Moisture (Ch. 5) Ground absorbs 45% of solar energy Page 2 Weather! Greenhouse effect

3 Atmospheric Pressure and Winds (AB7 Ch. 4) ATMOSPHERIC PRESSURE Pressure -- weight of column of air (1 hpa = 10 Newtons/meter 2 = 1 mb) Sea-Level Pressure Standard = 1,013 hpa WIND (AB7 PP L07) Air is Moved by Forces Pressure Gradient Force (F PG ) F = P/d P is the change in pressure over distance d Coriolis Force (F C ) Only affects 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 F PG = F C parallel to isobars Clockwise around highs in N. Hemisphere Counterclockwise around lows in N. Hemisphere Non-Geostrophic Winds (surface) occur when F PG F C force because of wind friction with surface inward to low, outward from high Regional Winds: (AB7 pp , L07) 1. Land & Sea Breezes Sea Breeze: (day) Insolation heats land, air rises, cooler air blows in from the sea. Land Breeze: (night) Water cools more slowly than land, air rises, cooler air blows from land. 2. Up & Down Valley Breezes Up-Valley Breeze: (day) Insolation heats air, air rises up mountain side. Down-Valley Breeze: (night) Air in contact with mountain surface cools, sinks down the valley. 3. Katabatic Winds Prevailing winds descend mountains (Chinook, Föen, etc.) High pressure forces winds over mountains (Santa Ana) 4. Monsoons Seasonal shifts in location of high and low pressure systems Asian Monsoon and North American Monsoon Page 3

4 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. Water Vapor Content (AB7 pp ) Psychrometric Charts! (L12) Specific Humidity Positive side where electrons rarely hang out Negative side where electrons mostly hang out mass of water vapor (grams) mass of air (kg) Relative Humidity Specific Humidity Maximum at Current Temp. Air Density (dry air) ρ = Pressure (Pa) ( 287)( T + 273) kg m Dry Air 3 C Moisture Content Review the Measuring Humidity worksheet! g water kg Dry Air g water m water kg Dry Air = = m Dry Air m Dry Air m Dry Air 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 Page 4

5 Cloud Development and Forms (AB7 Ch. 6, L15) 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 , L15) 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 3) Contrasts Between Land and Water (AB7 p. 72) continentality Land - changes temp. easily low heat capacity - heat stays on surface Water - little increase in temp. high heat capacity - evaporation cools high latent heat - light penetrates - water circulates Page 5

6 Lifting (AB7 pp , L11) Forced orographic (over mountains) Where does this happen? What s the result? frontal (know characteristic weather & cloud patterns on next page) convergent lifting convectional lifting Air Masses and Fronts (AB7 pp , L11) Air Masses Large volumes of air Move and collide Fronts form at collision zones Most weather takes place at fronts Page 6

7 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 Clouds Cirrus, Cirrostratus Cumulus & Cumulonimbus Cumulus then Clearing 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 Clouds Cirrus, Cirrostratus, Altostratus, Nimbostratus Stratus, Nimbostratus Clearing with stratus Precipitation Showers, snow, sleet or drizzle Drizzle None Page 7

8 Mid-Latitude Cyclones (AB7 pp , L11) Warm and cold air masses pushing 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 Dry Lines Separate air masses at same temperature (eg. ct next to mt in Texas) Humidity differs on either side Page 8