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59 Cards in this Set
- Front
- Back
- 3rd side (hint)
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Amount of Radiation varies with (2 things): Or what creates seasons
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Latitude and Time of year
-Because of spericity and the place where the sun is overhead varies |
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What affects duration and intensity of radiation
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Daylength and sun angle
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What is beam spreading?
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As sun angle decreases, beam is spread over a larger area.
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Beam depletion
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As sun angle decreases, path length increases, the result is more depletion (reflection and absorption) by the atmosphere
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Axial parallelism
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This causes the sun to be o/h at different places throughout the year.
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March and Sept Equinox
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Axis is NOT tilted with respect to the sun
-Noon sun angle is o/h at equator -12 hr days almost everywhere |
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Latent heat
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Heat associated with phase change
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Continentality
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refers to the larger daily temp change (or anual) experienced by inland locations, compared to coastal locations
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Why does water cool and heat more slowly than land?
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1) Specific heat: water has a high specific heat
2) Evaporation: it absorbs latent heat less e available to increase temp 3) Mixing: heat is mixed through a volume (wind blows it and mixes it up) 4) Transparency: the rdn. is absorbed through a volume as opposed to at one surface |
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What four factors control the global distributions of temperature?
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1) Latitude
2) Continentality 3) Ocean Currents 4) Altitude |
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One example of a warm current
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Atlantic Drift
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One example of a cold current
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Peru Current
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Why does temperature range increase with altitude?
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The atmosphere gets thinner and the Green House Effect is not as strong
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Why does temperature range decrease with cloud cover?
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Because the clouds absorb the long wave radiation from the earth and reflect the shortwave radiation from the sun during the day.
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In what two ways can air become saturated?
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1) Cool the air (to 7 degrees)
2) Evaporate water into the air (add 22mb) |
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Relative Humidity
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A relative measure of how close the air is to saturation.
OR Ratio of the actual amount of water vapour (VP) in the air to the max possible at that air temp (SVP) |
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RH=
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VP/SVP x 100%
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Td or Dewpoint temperature
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Temperature to which air must be cooled for saturation
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Tw
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wetbulbe temperature
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What happens when the air is saturated? ie.
RH=? VP=? Temp=? |
RH= 100%
VP=SVP Temp=Dewpoint temp |
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Radiation Fog
1. What is it? 2. How does it occur |
Occurs when there is radiational cooling
ie. It is night time and the earth is emitting more radiation than it is receiving. |
Conditions that maximize nighttime cooling like: long nights, calm wind (because harsh winds mix up warm air), clear skies
Add this with moist air and a light wind and you get fog. |
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How does dissipation of fog occur?
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Radiation enters through fog and warms up sfc of earth. Warm air rises and evaporates fog.
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Advection Fog
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Occurs via contact cooling
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What is contact cooling?
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Warm moist air cools to dewpoint by passing over a cold surface
ex. cold ocean current ex. Sanfrancisco |
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Steam Fog
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Often forms over water but not always.
-Thin and wispy, looks like steam |
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How does steam fog occur?
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cold air moves over a warm/moist surface.
-W.v is added to the cold air, bringing it to saturation ex. lake, fields, golf course, swamp (wet surface) |
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Adiabatic Processes
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-processes in which temperature changes without adding or removing heat
-expanding air cools and compressed air warms AND -rising air cools and sinking air warms |
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DALR
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Dry Adiabatic Lapse Rate
-rate of temperature change in rising or sinking unsaturated air parcel 10 degrees/km or 1degree/100m |
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SALR
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Saturated Adiabatic Lapse Rate
-rate of temp change in a rising or sinking saturated air parcel. -rate varies |
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LCL
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Lifting Condensation Level
-height at which a rising air parcel hits Td and begins to condense |
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LCL (equation)=
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LCL= 1000 (T-Td)/8.2
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Chinook Wind
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Hot and dry wind on leeward side of slope
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ELR
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Environmental Lapse Rate
-change in temperature with height in surrounding still air |
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Stability
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describes the tendency for air to rise or sink in the atmosphere
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Unstable air
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Rising air is warmer than surrounding air, ie it rises like a hot air balloon
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Characteristics of unstable air
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-warm afternoons
-cumulus clouds -good dispersal of pollutants -turbulence |
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Stable air
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Air displaced up or down returns to original position
-rising air is colder (more dense) than surroundings -inversions |
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Characteristics of stable air:
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stratus clouds
high pollution concentrations |
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Neutral air:
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Air displaced up or down stays put
-Rising air is the same temperature as surrounding air. |
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Why do rain droplets fall from clouds?
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Large drops overcome updrafts and fall from the cloud as precipitation
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What is collision- coalescensce process?
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-Droplets collide with other droplets and join together to form bigger droplets
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Ice Crystal Process
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-Most common in mid-lats
-W.V droplets decrease and add to Ice crystal droplets |
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Convectional Precipitation
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Warm air rises, cools and condenses = clouds and precip
-unstable |
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Characteristics of convectional precipitation
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heavy, large droplets, short duration, localized
-warm summer afternoons |
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Where does convectional precipitation generally take place ex of cities...
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Creates summer max. More precip in summer than in winter in Winnipeg and Saskatoon
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Orographic Precipitation
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Air is pushed up mountain and forms cloud at top.
-Rain shadow on other side --> desert |
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Precipitation associated with low pressure
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-Combines convergence and convection
?? get clarification from sheila |
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PGF
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Pressure Gradient Force
-A force that drives the wind -Results from the pressure gradient and causes air to move from high pressure to low pressure |
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CF
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Coriolis Force
-due to Earth's rotation -causes objects moving freely above Earth's surface to deflect from a straight line path |
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4 Things to Know About the Coriolis Force
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1) Acts at a right angle to the motion
-deflection to right of motion is NH -deflection to left of motion is SH 2) Affects direction, not speed 3)Strength depends on wind speed 4)depends on latitude. Increasing lat --> increasing CF |
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What is Newton's First Law of Motion
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When forces are BALANCED, object wll be stationary or will move at a constant speed in a constant direction
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What is Newtons Second Law?
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When forces are unbalanced, object will change direction and/or speed.
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Geostrophic Winds
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At least one km above sfc of earth
-no friction -only CF and PGF -result winds parallel to isobars -CF=PGF |
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How does movement of Geostrophic winds begin?
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It begins due to PGF. CF=0 until the motion begins.
-PGF is much greater than CF and wind accelerates. -As wind speed increases the CF increases and changes direction of the wind -Eventually CF=PGF -balanced forces means that the wind travels at a constant speed in a constant direction |
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Surface Winds
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-Within one km of surface
-PGF, CF and friction -winds cross isobars at an angle into the wind -PGF is greater than CF |
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In the northern hemisphere why are the subpolar lows dominant over the oceans in January?
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-Because cold continents raise pressure
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In the northern hemisphere, why are the subtropical highs dominant over the oceans in July?
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-Because warm continents lower pressure
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What are the east and west side of the subtropical highs like?
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Left= wet, moist and unstable
Right= cold and dry |
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Potential evaporation
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amount of evaporation that would occur if water was unlimited
-depends on energy |
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