Atmosphere and Weather Flashcards
What is incoming solar radiation?
Where shortwave UV insulation is the only energy input
What is incoming solar radiation affected by?
The amount and type of cloud & the sun’s angle
What happens to the incoming solar radiation?
1) around 5% is scattered by atmosphere
2) 24% reflected into space by atmosphere
3) 23% absorbed by atmospheric gases
4) 48% absorbed by Earth’s surface and heats it
What is reflected solar radiation?
The proportion of energy that is reflected back to the atmosphere (aka albedo)
What is true about lighter materials and reflected solar radiation?
Those materials have higher albedo values and therefore reflect more radiation energy
What is planetary albedo?
The proportion of insulation scattered and returned to space by earth
What is the process of surface/subsurface absorption? (4)
1) since darker surfaces absorb more radiation, energy is likely to be transferred o lower layers through conduction
2) if conduction is possible, surface will reman cool has heat is transferred to soil/bedrock
3) conduction is encouraged hen moisture is present
4) heat is released back to surface at night (offsetting night-time cooling)
What is the process of long wave radiation? (3)
1) since earth is a cold body, it emits long-wave radiation back to space
2) long-wave radiation is easily absorbed by greenhouse gases (water & CO2) and by clouds then heat is returned to the surface (this overall process is the greenhouse effect)
3) heat loss is greatest on cloudless nights
What is the daytime budget equation?
Insulation — (reflected insolation + surface absorption + sensible heat transfers + latent heat transfers + long-wave radiation)
What is the night-time budget equation?
Stored energy — (latent heat transfers + sensible heat transfers + long-wave radiation)
What happens to the cloud during the day?
Clouds ave a net cooling effect due to their albedo value causing insolation to be reflected to space
What is true about cirro clouds in cloud effects?
They allow insolation to pass through but not long-wave radiation
What is true about cumulonimbus clouds?
They do not heat or cool well
What is true about low thick stratus clouds?
They reflect 80% of insolation, keeping Earth’s surface cool
What happens to the clouds at night? (3)
1) thick clouds act as an insulating layer
2) they absorb and re-radiate long-wave radiation which keeps nights warm
3) warm clouds also emit long-wave radiation out to space
What is a part of sensible heat transfer (SHT)?
Convection and conduction
What is the process of convection (SHT)? (4)
1) thin air layer heated above surface (Poor conductor)
2) molecules vibrate more and gas is less dense so rises
3) air cools, becomes denser and falls to replace rising air
4) at night, air might sink in higher latitudes and advection may occur
What is conduction (SHT)?
Is the heat transfer between the ground and the air when they are in contact
What is the process of latent heat transfer? (3)
1) occurs when water evaporates to water vapour or ice melts into water vapour
2) heat required to change state is absorbed from the air leaving less energy to heat the surface
3) latent heat of condensation increases the speed and extent f convection
What is the process of evaporation? (2)
1) water molecules gain enough energy from surrounding air to change state to gas and leave the surface
2) overall less energy is left at the surface so the surface and air cool
What is the process of the formation of dew? (4)
1) water saturated air comes to contact with an object
2) object has cooler temperature than air’s dew point
3) water vapour condenses into liquid form
4) latent heat is released during condensation, adding heat to the ground
What is the process of absorbed energy returned to Earth?
Greenhouse gases absorb re-radiated long-wave radiation and atmosphere warms
What is the process of surface temperature change? (3)
1) during the day, the surface s heated by radiation, conduction and convection
2) surface air moves slow due to friction, then air heats up and rises due to convection
3) at night, ground is cooled by lack of radiation then heat from soil and rocks rise to heat surface
What is excess in the topic of the latitudinal radiation pattern?
Is the positive radiation budget in the tropics and it occurs because insolation is so concentrated
What is deficit in the topic of the latitudinal radiation pattern? (3)
1) a negative radiation budget at higher latitudes
2) insolation has a larger amount of atmosphere to pass through
3) more chance of reflection back to space and rays are less concentrated
What is balance in the topic of latitudinal radiation pattern? (2)
1) neither regions are getting warmer/colder
2) horizontal transfer from the tropics to higher latitudes compensate to global insolation differences
What are the temperature patterns in the topic of latitudinal radiation pattern? (4)
1) there is little seasonal variation at the equator but greater variation mid/high latitudes
2) lag time exists between overhead sun and maximum insolation while atmosphere is heated from below
3) coldest period is after winter solstice where the ground continues to lose heat despite the resumed insolation
4) greater lag time over the ocean due to high specific heat capacity compared to land
What are the pressure variations?
Air moves from high to low pressure and the low/declining pressure systems bring poor weather
What is surface pressure in the topic of atmospheric transfers? (2)
1) low pressure in equatorial regions while warm air rises and leaves the surface
2) higher pressures seen polar regions where cool air descends onto surface
What are surface wind belts in the topic of atmospheric transfers? (4)
1) they are uneven due to seasonal variation in insolation
2) summer in N.hemisphere causes cooling in S.hemisphere
3) thus increasing differences between polar and equatorial air
4) stronger high-level westerlies are created in the N.hemisphere
What is the ocean conveyer belt in the topic of atmospheric transfers? (5)
1) cold, salty water sinks from polar regions and moves towards equator
2) warm water gives its heat away to the surface winds
3) more evaporation in North Atlantic
4) saltier water is left behind which is denser then it sinks and cools
5) water is transported to Pacific and dilutes thus it is less dense so it rises
What is the truth about latitude in the topic of seasonal variations? (4)
1) between the tropics the sun’s angle is high
2) greater intensity of insolation is received thus more heating
3) where there is more atmosphere to pass through, a greater proportion of insolation is lost/scattered/reflected by the atmosphere
4) longer the sun shines, the more insolation is received
What is the difference in reflectivity between the land and sea in the topic of land/sea distribution?
Land has lower reflectivity thus, more absorption of radiation (apart from ice)
Sea has higher reflectivity thus less absorption of radiation (mainly with low sun)
What is the difference in heat between land and sea in the topic of land/sea distribution?
For land, heat is confined to near surface as surface has poor conductors
For sea, sun’s rays penetrate deep then convection currents distribute heat to great depths
What is specific heat capacity?
the amount of heat energy required to raise the temperature of unit mass of that substance by 1 degree
What is the difference in energy between land and sea in the topic of land/sea distribution?
For land, less energy is wasted to evaporation due to less water
For sea, large amounts of energy is used for evaporation
What is the difference in specific heat capacity between land and sea in the topic of land/sea distribution?
Land has a lower specific heat capacity thus a set amount of energy raises land temperature by more
Sea has a higher specific heat capacity thus a set amount of energy raises temperature by less
What are ocean currents?
Surface currents caused by prevailing winds
What is the movement of ocean currents?
There is clockwise rotation in N.hemisphere and anticlockwise rotation in S.hemisphere
What else is true about ocean currents? (7)
1) water piles into domes
2) due to earth’s rotation, water is piled up on western edge of ocean basins
3) warm currents from equatorial regions raise temperature in polar regions
4) warm surface causes low pressure
5) air moves from high to low so water moves from cold to warm
6) winds push warm into warm, exposing cold deep water
7) process repeats
What is return flow?
Narrow, fast current like the Gulf Stream
What is the significance of altitude in the topic of seasonal variations? (2)
1) air temperature decreases its altitude because air is thinner with less moisture
2) therefore air is less able o absorb long-wave radiation
What are pressure belts in the topic of seasonal variations?
They are the link between winds and pressure since heating air causes pressure changes that put air in motion creating the effect of wind
What is the significance of pressure changes in the topic of pressure belts? (3)
1) air is driven by the pressure gradient
2) air moves from high to low pressure
3) since earth is spinning, winds flow at angles due to the Coriolis force
What is the 3-cell model on air in the topic of pressure changes? (3)
1) high pressure is caused where air sinks to the ground
2) space is left for adjacent (next to) air at high altitudes to move over
3) thus add to weight of sinking air mass
What are wind belts?
Winds flowing from high to low permanent pressure zones (example: prevailing winds)
What is true about wind belts? (4)
1) air will move faster closer to the poles due to the distance between earth’s axis of rotation and the air
2) fast-moving air produces jet streams
3) air closer o the equator will move slower
4) faster moving air occurs at high pressure zones due to centrifugal force (outward force acting on moving earth) because pressure and Coriolis force work together
What is the Coriolis force? (3)
1) air masses deflect due to earth’s easterly rotation
2) air moving from high pressure to low pressure in N.hemisphere is deflected to the right
3) in the S.hemisphere, air moves to the left and acts at right angles to the wind direction
What is the geostrophic balance? (2)
1) the geostrophic wind is the resultant wind produced between the Coriolis force and pressure gradient
2) wind in N.hemisphere blows anti-clockwise around low pressure and clockwise around high pressure
What is friction in seasonal variations? (3)
1) reduces geostrophic force and wind speed
2) pressure gradient is no longer balanced by Coriolis force
3) makes air more likely to move to low pressure zones
What is the Inter Tropical Convergence Zone (ITCZ)?
A belt of low pressure circling the earth near the equator where trade winds of the N.hemisphere and S.hemisphere meet
What is Hadley cell in the topic of the 3 cell model? (4)
1) is adjacent to ITCZ where isolation is most intense
2) doldrums created (permanent low pressure belt) due to constant rising of air
3) trade winds are drawn in
4) air subsides around 30 degrees N/S and is deflected right/left depending on hemisphere
What is the Ferrel cell in the topic of the 3 cell model? (5)
1) not thermally induced but a result of adjacent cells
2) cog-like system created
3) air forced to rise at polar front
4) then forced to sink at high-pressure zone
5) then it meets the Hadley cell
What is the Polar cell in the topic of the 3 cell model? (3)
1) cold polar air sinks, creating high pressure
2) as air moves towards equator, it spreads out, pressure reduces and air rises
3) low pressure zone created at 50-60 degrees N/S
What are the Rossby waves?
Ridge and trough wave pattern of fast-moving ‘rivers of air’
What else is true about the Rossby waves? (5)
1) 3-6 waves in each hemisphere
2) courses can be altered by major barriers like the Andes mountain
3) if trough is present, air converges (low pressure system)
4) at a ridge in the wave, air diverges (high pressure system)
5) as wind rises over reassure ridges, conditions at surface change
What are the upper westerlies?
Fast moving winds resulting from a strong north/south temperature (and pressure) gradient and Coriolis force
What else is true about upper westerlies?
They are important or mixing warm and cold air but isn’t included in 3 cell model
What are jet streams??
They are narrow columns of fast-moving or through the centre of Rossby waves
What is true about jet stream value?
They are 10km above surface and have a speed around 250km/h
What two jet streams exist in each hemisphere? (3)
1) the polar jet (30-50 degrees N/S)
2) the subtropical jet (20-30 degrees N/S)
3) they both flow eastwards