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87 Cards in this Set
- Front
- Back
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air pressure
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created by motion (measured as temperature) and density of air molecules
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wind
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differences in air pressure; point a to point b = wind
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meridional flows
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N to S
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zonal flows
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E to W
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Speed
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anemometer
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Direction
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wind vane
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Westerly
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blows from the west to the east
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Southerly
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blows northward from the south
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Atmospheric circulation: primary
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global winds
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a.c: secondary
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high/low pressure systems
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a.c: tertiary
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local wind, temporal weather
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Driving forces for speed and direction of wind
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*gravity
*pressure gradient force *coriolis force *friction force |
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Gravity
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practically uniform at surface. w/out gravity...no atmospheric pressure
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Pressure Gradient
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air moves from high to low pressure= wind.
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high pressure
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denser air
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low pressure
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less dense air
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isobar
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line of constant value (isoline)
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why is there a pressure gradient in the atmosphere?
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unequal heating of the Earth's surface. polar air: cold, dense vs. equatorial air= warm, less dense
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low pressure_______
high pressure_______ |
rises
sinks |
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Coriolis Force
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Earth rotating; deflects any object from straight path that flows across the Earth
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Earth's rotation speed...
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varies with latitude
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Coriolis Effect varies..
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poles: max deflection
equator: 0 westerly winds (N. Hem) easterly winds (S. Hem) |
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Geostrophic winds
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winds in upper troposphere; paralles isobars.
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equatorial zone
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converging, ascending warm, wet air (cloud line)
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equatorial low pressure trough
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high energy and warming- lighter, less dense. converging moist, warm air
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ITCZ
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Intertropical Convergence Zone: combination of heating and convergence forces air aloft. Bands of clouds. vertical cloud columns...wet season shifts with ITCZ
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Trade winds
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pick up moisture. converging on the equatorial low pressure trough
NE trades: blow in N.Hem SE trades: blow in S.Hem |
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Hadley Cell
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trade winds..path
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Subtropical high pressure
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decending, diverging air. hot, dry, desert air. between 20 and 35 lat
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Subpolar low pressure
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cool and moist air. jan there are 2 low pressure cyclonic cells over the oceans at 60 N (n. pacific) (n. atlantic)
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polar high pressure
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frigid, dry deserts. weak, cold and dry winds move away from the polar region. anticyclonic dir. polar easterlies
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S. Hemisphere 3 zones
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pacific, atlantic, and indian
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Rossby waves
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wave like undulations (W to E)
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Jet stream
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upper westerly wind flow.
> 300 kmph polar 30-70 N along polar front. subtropical (weaker) 20-50 N |
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land-sea breezes
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diff. heating characteristics of land and sea create these
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mtn. valley breezes
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mtn. air cools rapidly at night; valley air gians heat rapidly during the day. warm air rises upslope in the da; at night cooler air subsides downslope
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katabatic breezes
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gravity drainage (stronger) elevated plateau or highland is essential to their formation
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Ocean currents
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closely interrelated to atmos. circulations. coriolis effect deflects ocean currents. driven by the circulation around subtropical h.p cells. clockwise around h.p
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deep currents
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downwelling-flow vertically and along the ocean floor-carry heat energy and salinity
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surface water
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swept away from coast
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oceans contain _____ of all earth's water
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97.22%
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freshwater is _____ of all earth's water
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2.78%
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surface water is _____ of all earth's water
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less than 1%
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properties of water
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stable bond-hard to break
versatile solvent: dissolves other elements and molecules |
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heat characteristics of water
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change from one state to another: solid, liquid, gas
heat energy absorbed or released. -drives weather patterns - >30% atmos. circulation driven by heat energy transfer during water phase change |
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liquid to ice (solid phase)
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as water cools (not ice yet) contracts in volume, increases density.
4 C (39 F) |
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water (liquid phase)
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not rigid like ice (conforms to container)
ice to water (melting) +80 calories for 1g (ice to water) *latent heat |
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liquid to solid
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latent heat released
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water vapor
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gas phase. molecules that are moving independently
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Latent Energy
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evaporation: water to gas
vaporization: boiling to gas(l.h. absorbed) condensation: gas to liquid(l.h. released) |
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sublimation
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ice to vapor
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Humidity
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water vapor in the air. air capacity f(temp) warmer ^ capacity
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relative humidity
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ration (%) RH= actual wv in air/ max wv capacity x 100
dry air: low rh moist air: high rh |
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saturation
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air at full wv capacity at given temp
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evaporation rate
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condensation rate
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100 % RH...
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rain, clouds, fog
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dew point temperature
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saturation temperature for a given air mass (in other words, temp when condensation occurs)
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Saturation air temp
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= dew point temp
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water vapor absorbs...
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infrared radiation
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Expressions of relative humidity
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vapor pressure
-air pressure molecules: water vapor, other molecules -wv portion of air pressure |
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saturation vapor pressure
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max. capacity wv in wir at a given temp
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specific humidity
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measured in mass...wv g/ air kg.
at any specified temp remains constant at temp and pressure change |
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air parcel
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specific temp and humidity characteristics ex: hot air balloon
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warmer air
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lower density, higher buoyancy
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cooler air
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higher density, lower buoyancy
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stability
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tendency for air to stay put or not. temp difference for air parcel vs. surrounding air
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normal lapse rate
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average decrease in temp with increasing altitude, a value of 6.4 C/1000 m. this is for still, calm air
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environmental lapse rate
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actual lapse rate at a particular place and time
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adiabatic processes
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the warming and cooling rates for a parcel of expanding or compressing air
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Dry Adiabatic rate
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"dry" air cools/heats
more cooling than (NLR) |
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Moist adiabatic rate
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saturated air parcel
more variable cooling f(moisture, temp) |
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why do we care about adiabatic processes?
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differences produces weather...unstable conditions!!!
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unstable
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air parcel warmer, less dense than surrounding air
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aggregation
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moisture droplets and ice crystals
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cloud condensation nuclei
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unstable air rises, saturates
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condensation of wv around nuclei
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dust, volcanic and fire ash, fuel combustion, sea salt over maritime oceans
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stratiform
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flat and layered, often low, grey (stratus-type) clouds
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cumuliform
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puffy and globular (cumulus-type clouds
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cirroform
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wispy, high altitude, often ice crystals oncoming storm (cirrus-type clouds)
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Fog
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cloud layer on ground
air temp= ground dew point temp |
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advection fog
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upslope fog - moist air cools as it rises
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valley fog
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cool air settles in low areas
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radiation fog
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cool surface chills air to dew point
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infiltration
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precip intensity
permeability initial moisture content |
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overland flow (runoff)
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soils with low permeability
think vegetation high precip intensity |
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Throughflow
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soils with high permeability
thick vegetation low precip intensity |
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streamflow
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gravity movement of water in channels
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