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
What else is true about jet streams? (2)
1) they result from differences in equatorial/sub-topical air and differences in sub-tropical/polar air
2) the greater the difference, the stronger the jet stream
What is evaporation in the topic of atmospheric moisture processes?
Occurs when vapour pressure of a water surface exceeds the vapour pressure in the atmosphere
What else is true about evaporation in the topic of atmospheric moisture processes?
It can increase speed if there is a low initial air humidity, there is heat and strong wind
What is absolute humidity in the topic of atmospheric moisture processes?
The actual amount of water vapor in a given ultime of air
What is the equation for relative humidity?
Actual moisture content x 100/ saturation moisture content at the same press + temp
What is condensation in the topic of atmospheric moisture processes?
Further cooling below dew point temperature or when an air mass reaches saturation turning water vapour into a liquid water
What 3 different coolings occur when hygroscopic condensation nuclei are present?
1) conduction cooling
2) radiation cooling
3) expansion cooling
What is conduction cooling?
This process leads to condensation when moist air comes in contact with a cold subject
What is radiation cooling?
Heat lost to space by long wave radiation from clouds and gases in atmosphere
What is expansion cooling?
Key word : expansion
Air rises and expands due to reduced pressure in the atmosphere where the expansion causes a temperature drop
What is freezing in the topic of atmospheric moisture processes?
When a liquid water changes into once temperature falls below 0 degrees
What is melting in the topic of atmospheric moisture processes?
The change of state from to solid to liquid above 0 degrees
What is deposition in the topic of atmospheric moisture processes?
The transition from water vapour to ice with no intermediate stage and occurs on surfaces
What is sublimation in the topic of atmospheric moisture processes?
The transition from ice to water with no intermediate stage and might occur in low humidity
What does precipitation need to occur?
Hygroscopic condensation nuclei
What is the collision theory?
Where droplets in clouds collide together, after rising and falling at different rates based on there size, to form a larger droplet
What is coalescence in the topic of collision theory?
When two droplets combine to form rain
What is aggregation in the topic of collision theory?
When two ice crystals collide to form snow
What is accretion in the topic of collision theory?
When ice crystals collect water droplet forming hail
What is the Bergeron-Findeisen Theory? (6)
1) air is saturated with ice before water is added
2) when air temperature is between -12 and -30 degrees, air can only be saturated over ice thus water droplets must evaporate
3) ice particles grow when air has a mix of ice and water (result of sublimation)
4) water vapour deposits on ice crystals
5) precipitation occurs once ice crystals have aggregated into a large enough snowflake to fall
6) when falling, ice may melt into rain
What is the process of convectional rainfall? (3)
1) land is heated and so, air directly above becomes less dense, rises and cools
2) as air rises further, latent heat is released, powering the ascent (upward movement)
3) when condensation occurs, clouds form and precipitation falls
What is the cause of conventional rainfall?
Unstable air where air parcels cools slower than surrounding air, forcing the air to rise
What is the process of frontal rainfall? (5)
1) warm air meets cold air
2) less dense warm air is too weak to push cold air out of the way
3) thus warm air is forced over cold air
4) warm air rises, cools and condenses forming a cloud
5) rain forms
Where does frontal rainfall occur?
In a centre of low pressure where two air masses intersect
What is the warm front in the topic of frontal rainfall?
A boundary of advancing warm air mass
What is the cold front in the topic of frontal rainfall?
A boundary of advancing cold air mass
What is the cause of frontal rainfall?
Conditional instability in air where stable is is forced to rise to where it hits dew point
What is the process of orographic rainfall? (3)
1) pressure force is strong enough to force air to move over a barrier
2) air rises, t cools and reaches dew point
3) clouds form, precipitation falls
What is the windward side in the topic of orographic rainfall?
This lee slope, ‘rain slope’ (aka rain shadow) is unsaturated air sinking then warming
When does hill fog occur regarding the topic of orographic rainfall? (2)
1) The forced ascent (upward movement) produces a thin stratiform cloud
2) unstable air, where he rising temp is warmer than the air rising, causes continued rising instead of falling down the lee slope
What is orographic rainfall caused by?
Conditional instability in air, where stable air to forced to rise to where it hits dew point
What is the process of radiation cooling? (9)
1) cloudless night
2) ground loses heat rapidly by return radiation to space
3) little wind present
4) air remains in contact with valley sides to cool by conduction
5) then sinks to bottom of valley
6) bottom of valley has a sources of moisture
7) ground temperature inversion occurs
8) warmer air on the sides (heated by morning sun, aided by dry ground) than the bottom
9) radiation fog is created then ice forms
What is the process of frontal inversion? (4)
1) colder, denser air mass descends
2) warmer air above is formed
3) barrier is created where cold air and warm air meet
4) warm air parcels are prevented from rising through to the warm air
What is the process for subsidence inversion? (4)
1) air moving upwards experiences adiabatic cooling due to pressure decrease
2) air falls and becomes denser and warmer
3) warm air reaches a cooler layer of unstable air
4) temperature inversion is created
What is adiabatic cooling?
While air expands, temperature decreases
What is ground temperature inversion?
Develops when air is cooled being in contact with a colder surface until the air becomes cooler than overlying atmosphere
What is temperature inversion? (2)
1) it dissipates on the sun has heated the ground long enough to cause cool air above warm air by conduction processes
2) warm air rises
What must a cloud be to produce precipitation?
It is tall enough to prevent sunlight from reaching its base
What does it mean if the cloud base is dark?
It is likely to be a nimbostratus cloud or cumulonimbus cloud
What is true about the cumulonimbus cloud? (2)
1) it stretches from sea level to tropopause
2) it forms an anvil head since cold air can’t rise through the warmer atmosphere
What is else true about clouds? (2)
1) It will not produce precipitation if it is thin enough to allow sunlight through
2) it may form fog if it comes in contact with a valley side/mountain top
What is rain?
Liquid water droplets heavy enough to fall to the ground
What size does rain usually become?
Between 0.5mm to 5mm
What is drizzle?
Rainfall less than 0.5mm
How does rain vary? (3)
1) amount
2) intensity
3) duration
What is hail?
Ice pellets made out of layers of concentric (has a centre) clear ice
How does hail form? (4)
1) raindrops carried to freezing level inside a cumulonimbus cloud to freeze
2) hailstones collide with supercooled water freezing on impact
3) rising and falling in the cloud causes repeated melting and freezing
4) hailstone becomes heavy enough to fall
How does snow form? (2)
1) snow crystals form when temp is below freezing
2) water vapour turns to solid
Where does the heaviest snowfall occurs?
When warm moist air is forced to rise in orthographic or frontal rainfall since dry cold air contains limited moisture
What is dew?
Deposition of water on a surface that occurs in anticyclonic systems
How is dew formed? (2)
1) rapid radiation cooling causes ground temperature to hit dew point
2) condensation/direct ground precipitation occurs
How does fog form? (3)
1) result of radiation cooling
2) when sun rises, fog lifts
3) possible smog forms under an inversion layer
What is an inversion layer?
Where cold air is trapped by warm air above it
Where is fog common?
Over the sea in autumn and spring
What is steam fog?
It is localized when cold air blows over warmer water thus the air becomes saturated due to evaporation. This results in condensation causing steam
What is the first way advection fog can be formed?
Key word: cold sea (3)
1) winds move towards pole over cold sea
2) chilled to below dew point
3) advection fog formed
What is the second way advection fog is formed?
Key word: current
And blows over cold ocean current, advection fog forms ever the current
What is the third way advection fog can be formed?
Key word: winter
Air passes from sea onto cold land in winter causing advection fog
What is another way hill fog can be formed?
If it is forced to rise due to relief and drizzle may fall if thick enough
What greenhouse gases are mentioned? (3)
1) water vapour
2) carbon dioxide
3) methane
What do greenhouse gases do? (2)
1) allow shortwave radiation to penetrate preventing long wave radiation
2) traps radiation inside the atmosphere causing temperature to rise
What evidence is given about CO2 in the topic of the enhanced greenhouse effect? (4)
1) co2 was 315ppm (parts per million): 1950 to 400+ppm: 2020
2) higher co2 due to increased fossil fuel burning and deforestation
3) trees that reduce emissions are removed
4) 5 gigatons of fossil fuel were burnt - 1 ton burnt = 4 tons of co2 emitted
What evidence is given about methane in the topic of the enhanced greenhouse effect? (4)
1) it increases t 0.5-2% per year
2) cattle produce 75m tons
3) wetlands produce 150m tons
4) methane is released as perma-frost melts
What evidence is given about CFCs in the topic of the enhanced greenhouse effect? (4)
1) increases 6% each year
2) 10 000x more efficient at preventing long-wave radiation from penetrating co2
3) used as refrigerants and aerosol propellants
4) destroys ozone, allowing for more insolation to enter the atmosphere
What evidence is given about nitrous oxides in the topic of enhanced greenhouse effect? (3)
1) increased by 8%
2) 300x more powerful than co2
3) come from fertilizers and burning fossil fuels & vegetation
What evidence is given about rising sea levels in the topic of enhanced greenhouse effect? (3)
1) 3.1mm per year
2) results from thermal expansion and melting glaciers
3) 60m of ocean warms by 0.11 degrees each decade
What evidence is given about ocean acidity in the topic of enhanced greenhouse gases?
Has increased by 26% since 1750
What evidence is given about melting ice and glaciers in the topic of enhanced greenhouse gases? (4)
1) showing signs of decrease in glaciers and ice
2) more land is exposed
3) sea level rises
4) arctic ice sheet sheet shrunk by 65% since 1975
How is fossil fuel burning related to the causes of the enhanced greenhouse effect?
Scientific consensus states it is directly related to the global temperature increase which includes the emission of gases
How is the albero change related to the causes of the enhanced greenhouse effect? (2)
1) deforestation and urbanization has resulted in more, much darker surfaces
2) ground absorbs more radiation which is released back not atmosphere (heating atmosphere)
What are the natural causes of the enhanced greenhouse effect? (6)
1) orbital eccentricity
2) axial tilt
3) axial precession
4) solar output variations
5) changes in ocean currents
6) creased atmospheric dust from volcanoes
What are the facts on El Niño that are related to the enhanced greenhouse effect? (4)
1) it heats up the planet as normal westward surface flow of currents reverse
2) wam water moves east
3) results in high temperature d drought in Australia
4) also results in heavy rainfall in Peru
What does El Nina produce?
(Enhanced greenhouse effect)
Colder years as a result of cool upwellings off the Peruvian coast
What are the consequences of sea levels as a part of atmospheric impacts? (6)
1) 200m people can be displaced
2) 4mil km2 of land threatened by floods
3) 200mil people at risk from floods
4) rise in sea levels by 2100 is expected to be 26-77cm
5) 570 cities exposed to contamination of drinking water
6) millions of coastline miles under threat
What are the consequences of warming oceans as a part of atmospheric impacts? (3)
1) 50% increase in marine heatwaves this decade
2) 1 degree fluctuation causes plankton and coral to stress and bleach (spit out symbiotic algae and die)
3) first 700mil of ocean absorbs most heat
What are the consequences for storm activity as a part of atmospheric impacts? (2)
1) more frequent and intense hurricanes, tornadoes, etc
2) flood causes: a] 500 000 deaths, b] affects 2.8bn globally, c] $8 billion in damages (USA)
What are the consequences for agriculture as a part of atmospheric impacts? (5)
1) USA”s grain belt will decrease
2) China’s growing season will increase
3) Northward shift for timber and crop production
4) 35% drop in African produce if 3 degrees temperature rise
5) $10bn in losses in Texas and Oklahoma in a year due to fail crops
What are the consequences for drought as part of atmospheric impacts?
Reduced rainfall in Europe and USA will expose 4bn people to shortage risks
What are the consequences for diseases as a part of atmospheric impacts?
60 million more people are exposed to malaria because mosquitoes breed faster in heat
What are the consequences for wildlife as a part of atmospheric impacts?
40% of species will become extinct at +2 degrees
What are the consequences for tourism as a part of atmospheric impacts?
Previously undesirable areas may become tourists hotspots, likewise for desirable places becoming undesirable
What are the costs of co2 as a part of atmospheric impacts? (3)
1) 1 ton of co2 causes £45 of damage
2) solving effects would cost 5-20% of country’s GDP
3) now, action can only cost 1% of each GDP
How is higher temperature a general impact in the urban climates theory? (6)
1) greater surface area to absorb heat
2) low albedo of tarmac (10%) and concrete (20%) thus less insolation is reflected (higher specific eat capacity surfaces)
3) high buildings trap insolation and absorb heat
4) low building cause street to collect heat
5) more heat can accumulate for atmosphere due to reduced evapotranspiraton
6) pollutants trap heat
How is lower humidity a general impact in the urban climates theory? (3)
1) lack of vegetation so less transpiration
2) high drainage entity removes water
3) fewer bodies of water so less water available to evaporate
How are more intense storms a general impact in the urban climates theory?
There is greater instability of air nice stronger convection above urban areas
Why are there slower winds due to the general impacts in the urban climates theory?
Wind is scattered by buildings
Why is there less snowfall due to the general impacts in the urban climates theory?
Higher temperatures
How are human activities a general impact in the urban climates theory?
Radiant heat from heating systems and building can contribute up to 50% fro human activities
Where are the tiny specific anomalies found in the urban climates theory?
Often above canals and rivers
How is insolation a general impact in the urban climates theory? (4)
1) due to pollution, long wave radiation is trapped
2) insolation is reduced
3) warming occurs by the afternoon
4) mornings are colder than in rural areas
What is a microclimate mitigation example??
London plane tree
What is microclimate mitigation? (2)
1) installation of urban forest
2) reduces ambient temperatures by 3-5 degrees by shading and increased evapotranspiration
