The Earth System Flashcards
What are the 5 components of the Earth System ?
atmosphere,
biosphere,
lithosphere,
cryosphere,
hydrosphere
Who suggested that the Earth was a functioning system?
Lovelock (1970) known as Gaia hypothesis. Initially rejected but then accepted
What are the 3 timescales?
- Cyclic time (10 x4)
- Graded time (10 x2)
- Steady time (10 x-1)
What are seasons induced by?
Orbitally induced.
What do orbitally induced seasons mean for the earth? There are 2 things.
- Annually varying daylight.
- Seasonal variation in temperature.
What is Electromagnetic energy?
Electromagnetic (ER) - Solar energy is radiation from thermonuclear sun.
ER becomes chemical via photosynthesis
What is kinetic energy?
Motion (energy of transport)
What is Potential energy?
When mass falls under gravity
What is chemical energy?
(as in biological material) It is captured by photosynthesis and then converted to heat, motion
What is heat energy?
It is thermal energy which is generated by vibrating molecules.
What is heat actually?
The total kinetic energy of all the molecules of an object; faster molecular movement means higher temperatures.
What is temperature actually?
Measure of the mean kinetic energy (speed) per molecule of an object (internal energy).
What is conduction and convection?
Conduction: Heat can be transferred as conduction – directly one material to another.
Convection: upward and circulation movements in fluids.
What occurs during the latent heat process?
There is an energy change. For example, vapour to water releases energy and visa versa.
What is the 1st law of thermodynamics?
energy can neither be created
or destroyed, but it can change form
What is the second law of thermodynamics?
Heat always moves from hotter objects to colder
objects, unless energy in some form is supplied to reverse the direction
of heat flow.
How does solar radiation vary?
Solar radiation occurs as a spectrum of different wavelengths. We sense these in different ways (UV,
visible light, infra -red)
Do clouds cause an albedo or absorb?
They can do both (when they absorb they re-radiate it).
In what was is energy usually re-radiated from Earth?
As it is cool it radiates in longer wavelengths - mainly infra-red.
Why are smaller wavelengths of radiation dangerous to organisms?
they can alter atoms = ionizing radiation (UV
upwards).
Do atmospheric gases absorb incoming or outgoing solar radiation?
Both.
Absorb incoming at lower rates than they absorb outgoing radiation - particularly infra-red radiation.
What is net radiation?
Net radiation is usually measured at the top of the troposphere.
Net radiation is the difference between incoming and outgoing energy. Usually balances itself out.
What is radiative forcing?
This is when there is a temporary imbalance in net radiation following the rebalance of the energy which causes variation in temperature.
What is perturbation?
When various evets change the energy balance.
EG: Volcano causes ash which blocks incoming radiation causing cooling.
What is negative radiative forcing?
When there is a change in the atmosphere resulting in less radiation and therefore decline in temp.
Can you give an example of positive radiative forcing?
Increasing greenhouse gas concentration. Causes upward temp adjustment such as the earth emitting enough to achieve new balance.
Who do you cite for any earth system atmosphere lectures?
Thomas (2023) (Atmosphere lectures)))
What is maritime tropical air and who experiences it?
W Europe/western N America .
It is humis.
What is maritime polar air and who experiences it?
W Europe and W. N. America.
It is also humid but also unstable unlike MTA.
What is continental polar air?
Cold, dry and stable.
Do air masses mix?
NO they keep their identity and don’t mix.
What air mass is unstable in N America and what does it cause?
Gulf MT air is highly unstable due to warm Atlantic
and Gulf Stream: hurricanes are generated here.
What does the word monsoon mean?
The switching of wind direction as the ITCZ moves north and south through the trade wind areas.
This causes a dry monsoon season and wet monsoon season
What are the characteristics of the Asian monsoon?
Winter high in Asia, subsidence, dry, outflowing winds.
Summer movement N of the ITCZ causes rising air, with trade winds drawn towards the continent from the sea (blow from SW), bringing moisture (deflected by Coriolis) and precipitation.
What does the summer monsoon mean for Asia? 4 things.
- Seasonal rain supports rainfed agriculture.
- 50% India population relies on agriculture.
- Replenishment of water stores such as snow in Himalayas.
What was responsible for the enhanced effected of the Australian wildfires?
The southern part of Australia should get winter rain from the westerlies, but they were flowing further south and there was little precipitation.
What occurs during an El nino year?
Warm pool shifts east.
Cooler water and higher pressure in west.
Reduced precipitation over eastern Australia.
What occurs during a La nina year?
Warmer than normal sea surface in west Pacific, cooler than normal in east Pacific.
Convection and rain affect eastern Australia.
What are the normal conditions of the Pacific, not during an el nino or la nina year?
Warm sea surface in west Pacific, upwelling
of cool waters off S.America.
Winds blow to the west.
What are fronts?
Fronts occur on different scales and are associated with precipitation and temperature changes.
Can you give an example of a front which would cause instability?
A cold air mass pushing into a warmer, moist one typically sets up a steep temperature gradient
(instability) and warm moist air rises far and fast – setting up the possibility of severe storms.
How are thunderstorms created?
Heating at surface and unstable conditions lead to rising air, cloud.
Falling rain in cloud evaporates and cools (LH), causing sinking (downdraft).
Wind shear can separate up and down drafts allowing storm to persist for hours.
What is wind shear?
Difference in wind speed or direction over a relatively short distance, either vertical or horizontal
How are tornados formed?
Warm rising air meets cooler air aloft, creating turbulence, winds rotate because of
wind shear: wind direction changes and wind speed
increases with height.
The spinning can generate sufficient strength to extend a funnel cloud down to the ground.
What is a mesocyclone and can you give an example of one?
A tornado is a mesocyclone (a storm
in a cloud) .
They may be up to 10 km across
What 3 atmospheric processes have the same processes but different names? What are 3 features?
Hurricane, cyclones, typhoons
1. Wind speed at least 74mph.
2. Sea surface temp must be 27 degree +
How does the Coriolis impact the spinning of hurricanes?
Spin anti-clockwise in NH, clockwise in SH.
How do moving troughs of low pressure impact tropical cyclones?
They can create them.
This is through these low pressure troughs denote zones of low level convergence which produces uplift and thunderstorms. May occur in the tropical Atlantic.
Storms may be created due to wind shear which may impact rotation and cause thunderstorms - which can transform into tropical depressions.
Why does energy redistribution occur?
Energy surplus and deficit of the planet, prior to circulation effects.
Polar regions lose net energy; equatorial regions gain net energy.
What is sensible heat transfer?
Conduction causes more energy in air parcel,
more molecular movement, decreasing density and
thus rising up (convection)
What is latent heat transfer?
The process which causes latent heat energy.
What are turbulent heat fluxes?
Processes which involve a movement of heat.
What is atmospheric pressure and what is t measured in?
The standard atmosphere is a unit of
pressure defined as 1013.25 millibar.
It reflects the weight of the atmosphere. It is approximately the average pressure at the Earths surface.
Is pressure even in all parts of the Earth?
No, due to rising and falling air masses.
What is the Coriolis effect?
Apparent deflection of winds (or other moving objects) due to the faster rotation of the Earth at the equator than higher latitudes. Air moves right in NH and Left in SH.
What are geostrophic winds?
In the upper troposphere, no surface friction, so winds
flow along the pressure gradient, due to Coriolis.
However, friction impacts wind at the surface.
What are jet streams?
In the upper atmosphere, steep pressure gradients are linked to fast flowing geostrophic winds
What are 5 of the major surface wind patterns?
1) The Coriolis effect deflects winds
2) Surface friction that slows winds and reduces the Coriolis effect.
4) Effects of variable heating and cooling of the oceans and land.
5) Effects of upper-level features, such as jet streams and Rossby waves, create weather systems
What is the ITCZ?
A global zone of circulation characterised by rising air, low pressure and convection, seasonal shifts.
What are tropical trade wind belts?
Easterly surface winds moving from areas of subtropical high pressure towards the ITCZ. In these areas, ocean temperatures are warm.
- At sea, winds generally predictable and useful, hence
the name (trade winds).
What are subtropical deserts (4 features) and why do they occur?
They are made from the descending limb of the Hadley cell.
1. High pressure, little or no rainfall
2. Clear skies
3. Large diurnal temperature fluctuations
4. At sea, calms (the “horse latitudes”)
What is the subtropical jet?
The subtropical jet is a fast-moving band of air high in the troposphere caused by a steep pressure gradient—warm rising air to cooling sinking air.
What are 3 characteristics of the polar cells?
- Cold, dense air over the poles sinks
- Typical weather is cold and clear, low precip.
- Temperatures largely driven by latitudinally varying insolation (e.g. 24 hr sunlight/darkness) .
There is a low height of the troposphere over poles.
What is the polar front?
A latitudinally mobile region of generally variable weather.
Incursions of warmer temperate air occur in the lower latitudes of polar regions bring precipitation.
What are Rossby waves?
They are as result of the Earths rotation and they impact the surface weather features.
Waves tend to take certain forms more frequently, due to topographic features.
What is a polar vortex?
A strong flow enclosing the cold polar cell.
Why do people disregard the Ferrell cell?
It is an area of highly variable atmospheric movement.
Travelling lows (and intervening high-pressure “ridges”) lasting a few days are a feature and it is thus the most variable on the planet.
how are depressions formed at the polar front?
Warmer air from the south meets the cold polar air – zone of mixing of cold and warm air.
This causes low pressure at the surface.
What is cyclogenesis?
A vertical motion set up by swings in the horizontal airflow; the moving air is rotation caused by Coriolis: here, clockwise in surface highs and anticlockwise in lows (reversed in S Hemisphere)
What are General Circulation Models?
Depict the major movement of the atmosphere –
pressure, winds, rising and falling air masses.
What are weather models?
Atmospheric and surface grid cells.
The model makes sets of computations in time-steps in which all adjacent cells interact. This can be based on previous knowledge too.
What are climate models?
Ensembles of daily weather information, with outputs summarised as climate statistics (averages, variance and means).
Average weather maps are created for decades at a
time.
They produce long term changes.
Why is vertical movement in the atmosphere so important?
Upward motion transfers a significant amount of energy from the surface to the atmosphere.
What is humidity?
The absolute amount of water vapour in air.
What is the saturation point?
The amount of water that the air can hold.
Warm air holds more moisture than cold
What is the relative humidity?
The % of saturation.
What happens when unsaturated warm air cools?
When unsaturated warm air cools it becomes saturated and condenses (clouds form).
What is a lapse rate?
The lowering of temperature upwards in the atmosphere.
What is the Environmental lapse rate?
The rate of temperature fall with altitude. It implies that there is no air movement.
What 4 ways is heat released from the atmosphere?
- Radiation
- Conduction
- Convection
- Latent heat transfer.
What does DALR and SALR stand for?
Dry Adiabatic Lapse Rate
and
Saturated Adiabatic Lapse rate
What does adiabatic mean?
Without energy loss.
True or false: If an air parcel is less dense but colder than surrounding air it will rise?
False, has to be lighter than the surroundings.
How are clouds impacted after they have rained?
Water vapour condenses to liquid water
and releases LATENT HEAT, which warms the
parcel, decreasing its rate of cooling. It
continues to rise at the SALR and clouds form
What is cloudseeding?
Traditional method of rain-making.
What is conditional instability and how is it impacted by ELR?
Where the ELR is between the DALR and SALR (MALR).
This is when a dry parcel will not move upwards, but a saturated parcel will.
However, when ELR rises slowly a saturated air parcel can rise as its rate of cooling exceeds that of the ELR.
At a local level, what can prevent warm air from rising?
A temperature inversion (when temperature is higher in a level higher-up). This is shown via smogs.
What does cold air drainage at night lead too?
Frost pockets and formation of early-morning mist or fog in cold air.
How do land-sea breezes impact weather and cloud formation?
Day: land warms fast and air rises over land, then, clouds may form over land (sea breeze feels cool).
Night: land cools faster than sea, cooler air sinks
and circulation reverses (land breeze feels warm)
What are katabatic winds and what are they caused by?
They are a topographically driven weather phenomenon.
Caused by: dense air moving under gravity.
What are shelter belts?
Line of trees etc used to protect vegetation or organisms from the wind speed.
What is the Venturi effect?
Concept that air flow can be funnelled into narrow passages between buildings.
What are transverse currents?
Wind currents which develop when buildings are at right angles to the wind.
What kind of molecule is water?
POLAR molecule.
Electron density (-ve) focused on the O atom and H atoms having a relatively more positive charge.
Unlike charges attract.
What are the 4 main water reservoirs?
- Atmosphere
- Ocean
- Polar Ice/glaciers
- Terrestrial
How much water is found in oceans?
96.5%
How much freshwater is there?
2.5%
What % of freshwater is found in glaciers and icecaps?
68.7%
How long does water reside in atmospheric water?
10 days
How long does water reside in world oceans ?
3600 years
How long does water reside in rivers and lakes??
Rivers: 2 weeks
Lakes: 10 years
How long does water reside in soil and biological water?
soil: 2-50 weeks
biological water: a few weeks
How long does water reside in ground water?
10,000 years
How long does water reside in permafrost?
1 million years +
How long does water reside in polar ice?
over 800,000 years ago
What is the Gulf Stream?
Wind-driven current that brings warm, saline waters north.
Together with dominant westerly winds the Gulf Stream helps to keep western Europe warmer than equivalent latitudes.
What is the Gulf stream also known as?
Atlantic Meridional Overturning Circulation (AMOC)
What are gyres?
Coriolis directs the warm western boundary
currents along the coasts of N and S America,
eastern Australia, Asia and Africa.
They do not move much.
Five subtropical GYRES located 30° N and S
What is deep ocean circulation?
Deep ocean circulation is not driven by winds but
differences in density (related to temperature and
salinity).
Water takes several centuries to circulate completely (estimates vary).
What is the movement found in deep water circulation?
Warm waters from the equator flow towards the high latitudes, cool, sink and return towards
the equator.
Also furthered by sea ice sheets.
What 6 processes can form lakes?
- Glacial
- tectonic
- Thermokast
- river erosion
- Meteor impact
- volcanic eruption
What is the largest freshwater lake on Earth?
Lake Baikal is the largest body of
(unfrozen) freshwater on Earth:
23,600 km3. It is in Siberia.
What were the Great Lakes formed by?
All formed by the Laurentide ice sheet during the Last Glacial Maximum – approx. 20,000 years ago.
What lake is an example of a tectonic lake?
Crater Lake, Oregon.
It is 600m deep and formed 7600 years ago in a
cataclysmic eruption of Mt. Mazama.
The lake lies within a Caldera – a collapsed magma reservoi6.
What 3 elements make up the cryosphere?
- Glacier and ice sheets
- Sea ice.
- Permafrost.
What are sub-glacial lakes and give an exmaple?
Form under ice sheets and can remain isolated from
the hydrosphere for long periods.
The most famous is Lake Vostok, 4 km beneath the
Antarctic ice sheet.