1
Q
What is a system?
A
Any ordered, interrelated set of ‘things’ (a lake in a watershed, the earth and the sun) linked by flow of energy or matter. The system must be conceptually separated from the surrounding environment outside the system. A system can have subsystems.
2
Q
What are the 4 attributes of environmental systems?
A
- Function (structure and fluxes)
- Scale
- Feedbacks
- Equilibrium states
3
Q
What is an open system?
A
Inputs of energy and matter flow into the system, and outputs of energy and matter flow from the system. Inputs of matter and energy undergo conversion and are stored or released as the system operates.
For example: earth and solar energy entering, heat energy leaving.
4
Q
What is a closed system?
A
A system that is shut off from the surrounding environment. Closed system links the input and outputs.
Example: water cycle
5
Q
What is an environmental system budget?
A
What comes into the system and what leaves the system.
Inputs - Outputs = change in storage
- if the inputs are larger than the outputs, the change in storage increases.
- if the inputs are smaller than the outputs, the storage decreases.
6
Q
What are the functions of a forest?
A
- changing the climate
- keeping the surface of the soil cool
- nutrient storage, stored in the canopy
- biomass that contains carbon
- exchange of gases with the atmosphere
7
Q
Explain a leaf during the day vs night as an open system.
A
Day: photosynthesis dominant
- Sunlight as an energy input and water, nutrients and CO2 as energy inputs.
- photosynthetic process converts the inputs to stored chemical energy in the form of sugars (carbohydrates).
- releases oxygen as an output.
Night: no photosynthesis = respiration dominant
- input: mainly O2 from atmosphere but also H2O, minerals and nutrients.
- carbon is converted in CO2.
- output: water lost through transpiration and leaf loses heat because of cool off.
8
Q
Controls on leaf CO2 exchange:
- nutrient (nitrogen)
- temperature
- light
A
- nitrogen: linear (+ nitrogen = + chlorophyll)
- temperature: not linear, but max value at which rate can rise, then decline.
- light: non-linear (dependant on light)
9
Q
Define negative and positive feedback.
A
Negative: feedback information discourages change in the system. Further production of the feedback opposes system changes and leads to stability.
Positive: feedback information encourages change in the system. Further production of positive feedback causes system change.
10
Q
Define steady state equilibrium.
A
When the rates of outputs and inputs in the system are equal and the amounts of energy and matter in storage within the system are constant. Negative feedbacks dominate.
11
Q
Define dynamic equilibrium.
A
Steady state equilibrium that demonstrates change overtime. Positive feedbacks dominate is driven by unstable equilibrium.
12
Q
Radiation and temperature.
A
All bodies that possess energy emit ‘radiation.’ Temperature is a measure of how much internal energy a body has.
The higher the temperature,
- the more radiation is emitted
- the shorter the wavelengths emitted
13
Q
Define solar constant.
A
Average value of insolation when earth is at its average distance from the sun = 1370/m^2. The constant varie due to sun spot cycles.
14
Q
What are the reasons for variation of insolation with time and space.
A
- Earth’s revolution.
- Earth’s rotation.
- Tilt of the Earth’s axis.
- Earth’s Sphericity.
15
Q
Explain insolation on a curved surface.
A
Differences in the angles at which solar rays meet the surface at each latitude results in an uneven distribution of insolation and heat.
- full radiation received at the equator (sub polar point).
- more concentrated, smaller areas to cover near the equator receive more insolation.
- more diffuse, larger areas covered at the tropics receive less insolation.
16
Q
Define net radiation.
A
The balance between incoming short-wave energy from the sun and all outgoing radiation from the earth and the atmosphere.
Energy inputs minus energy outputs.
17
Q
Define seasonality.
A
Refers to both to the seasonal variation of the sun’s position above the horizon and to changing day lengths during the year. Seasonal variations are a response to changes in the sun’s altitude or the angle between the horizon and the sun. These are caused by the variations of solar radiation (4).
18
Q
Explain air pressure and the temperature of composition of atmosphere.
A
Air pressure changes throughout the atmospheric profile - divided by the Earth’s layers.
- dense collection of gases towards the surface, less dense as we go higher.
- with increasing altitude, density and pressure decrease.
- temperature decreases as we go upwards towards new compositions of the earth. At the certain point, it starts to increase due to the ozone layer capturing solar radiation.
19
Q
Define transmission, atmospheric scattering/reflection, atmospheric absorption.
A
- Passage of parts of shortwave and long wave radiation through the atmosphere (atmosphere is ‘transparent’ to these components).
- Atmosphere interacts with insolation through processes of scattering, a redirection of radiation through refraction and reflection from particles (aerosols and water droplets).
- Some of the short short and long wave radiation is absorbed (and heats up) some constituents in the atmosphere.
20
Q
Explain the ‘Greenhouse’ Effect.
A
- without GHGs, the earth’s temperature would be around 255K (if earth was a black body).
- average surface temperature of the earth is 288K.
- the difference between the two temperature is 33 degrees: magnitude of the greenhouse effect.
- increased greenhouse effect contributes to global warming and climate change.
21
Q
Explain the ozone layer.
A
- Ozone absorbs the shorter wavelengths of UV radiation.
- UV energy is converted to heat energy - it filters the Sun’s harmful rays. When it absorbs solar radiation, the ozone layer warms up.
22
Q
What causes the depletion of the ozone layer?
A
- CFC production - when chlorine reacts with a one and depletes the ozone layer.
- Strong, stable and cold polar vortex and very cold temperatures in the stratosphere (ozone hole).
23
Q
Explain how ozone warms and cools the earth.
A
Warms:
- absorbs UV radiation = heats the stratosphere.
- absorbs IR radiation emitted by earth’s surface = traps heat in the troposphere.
Cooling:
- major ozone losses observed in lower stratosphere due to CFCs have a cooling effect.
- the absorption of radiation is decreased by depletion of ozone - the radiation is reflected by albedo effect = cooling.
- ozone is cooling when it is lost in the stratosphere.
24
Q
How does the Montreal Protocol protect the carbon sink?
A
Increased UV radiation decreases NPP - it is destroying the photosynthetic capacity of plants = decrease in CO2 uptake.
With no Protocol, it would lead to higher atmospheric concentrations of CO2 and contribute to accelerated global warming.
INDIRECT effect of reduced O3 depletion.
25
Explain the effect of angle on reflection and absorption of radiation by water.
High latitude:
- radiation coming into water through a low angle.
- high reflection (33%).
- lower absorption (67%).
Low altitude:
- radiation coming into water at a higher angle.
- low reflection (5%).
- higher absorption (95%).
26
Explain the different types of heat.
1. Sensible heat: can be sensed by humans as temperature because it comes from the kinetic energy of molecular motion. Transfer - surrounding bodies are heated (air, water, soil).
2. Latent heat (hidden heat): energy gained or lost when a substance changes from one state to another. Uptake and release of energy.
These are part of the radiative loss: dependant on the temperature of body.
27
Explain the different methods of heat transfer.
1. Radiation: transfer of heat in electromagnetic waves.
2. Conduction: molecule-to-molecule transfer of heat energy as it diffuses through a substance. Diffusion of sensible heat.
3. Convection: the transfer of heat by mixing or circulation. Sensible heat energy is transported by motions of a fluid (liquid or a gas).
28
Define scattering.
Atmospheric gases, dust, cloud droplets, water vapour, pollutants physically interact with insolation to redirect radiation, changing the direction of the light’s movement without altering its wavelengths.
Scattering accounts for a percentage of the insolation that does not reach the Earth’s surface but is instead reflected back into space.
29
Define diffuse radiation and direct radiation.
Diffuse radiation: incoming energy that reaches earth’s surface after scattering occurs. It is a weaker, dispersed radiation composed of waves travelling in different directions, so casts shadow-less light on the ground.
Direct radiation: travels in a straight line to earth’s surface without being scattered or otherwise affected by materials in the atmosphere.
30
What happens if cloud cover increases?
1. Increasing albedo, cooling.
- Increase in cloud cover = increase in short wave reflection.
- More of the solar radiation is being reflected back into space.
2. Insulating, warming:
- Clouds have the ability to absorb long wave radiation from the surface.
- Great cloud cover = great absorption = reradiated to earth’s surface.
31
What is the effect of cloud height/type on radiation budget.
1. High Cirrus clouds:
- warming.
- high, thin.
- modest reflection of shortwave insolation.
- most shortwave insulation transmitted to surface.
- long wave radiation absorbed and reradiated back to the surface.
2. Lower Stratus clouds:
- cooling.
- low, thick clouds.
- long wave radiation emitted to space.
- most shortwave insolation reflected to space.
32
Explain the surface energy budget in the soil.
- heat is transferred downward into the soil during the day by conduction during the day (or summer).
- heat is transferred upward toward the surface by conduction at night (or winter).
- at a certain depth, energy exchange becomes negligible.
33
Define latent heat of evaporation.
Energy stored in water vapour as water evaporates. Water absorbs large quantities of this latent heat as it as it changes states to water vapour, thereby removing the heat energy from the surface.
34
Define sensible heat (H).
Heat transformed back and forth between air and surface in turbulent eddies through convection and conduction within materials. The activity depends on surface and boundary layer temperature differences and on the intensity of convective motion in the atmosphere. Bulk of NET R is expended as sensible heat in dry regions.
35
Define ground heating and cooling (G).
The flow of energy into and out of the ground surface (land or water) by conduction.
36
Define pressure gradient force.
Drives air from areas of high pressure (more dense air) to areas of low pressure (less dense air). High and low pressures exist due to the unequal temperatures of Earth’s surface, thereby causing winds.
For example, cold, dry, dense air at the poles exerts greater pressure than warm, humid, less-dense air along the equator.
37
Explain the effect of pressure gradient on wind speed.
Close isobars denote steepness in pressure gradient. A steep gradient causes faster air movement from a high-pressure area to a low-pressure area. Isobars spaces wider apart mark a more gradual pressure gradient, one that creates slower air flow.
Winds are stronger around low pressure areas. Winds are slower at high-pressures.
This determines wind intensity.
38
# Define Coriolis effect.
What are the effects of Earth’s rotation? What are the effects of Earth’s latitudes?
Deflective force that makes wind travelling in a straight path appear to be deflected in relation to the Earth’s rotating surface. This force is an effect of Earth’s rotation.
Because Earth rotates eastward, objects appear to curve to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.
Because the speed of Earth’s latitude varies with rotation, the strength of deflection is weakest at the equator and strongest at the poles.
39
What are the characteristics or ITCZ (intertropical convergence zone).
- constant high sun altitude and consistent day length (12 hours) = large amounts of energy available at the equator during the year.
- warming from energy surpluses creates lighter, less-dense air with winds converging the low-pressure area.
- converging air is moist and full of LE.
- rainfall is heavy: air rises, expands and cools = condensation.
- winds are clam due to low pressure gradient.
40
Explain surface ocean currents.
- deflected by Coriolis force.
- the oceanic circulation systems are known as gyres and appear to be off-set toward the western side of each ocean basin.
41
What are the ocean currents in the hemispheres?
Northern: winds and ocean currents move clockwise about high-pressure cell.s
Southern: counterclockwise.
42
Explain thermohaline circulation.
- differences in temperature and salinity produce density differences important to the flow of deep currents on Earth known as thermohaline circulation.
- slow movement of water betweenPcific and Atlantic Oceans, at surface and at depth.
- transfers warm water from Equatorial Atlantic to North Atlantic, where cools, becomes denser with salt and sinks.
- important transfer mechanism for heat from Equator to Northern Hemisphere.
43
Explain the relation between altitude (elevation) and temperature.
The atmosphere thins with altitude, so decrease in atmospheric ability to absorb and re-radiate heat with elevation.
At higher altitudes, insolation is more intense: less atmospheric gases to travel through.
Less greenhouse blanket over head due to the thin atmosphere, so does not warm the air as much.
Produces lower mean T and greater day/night contrast.
44
Explain the temperature conditions near sea level.
Higher mean T and less day/night contrast.
45
Explain the relation between clouds and temperature.
- Related to atmospheric moisture levels as well as ground moisture levels.
- Clear sky areas: larger daily and annual T ranges.
- Cloudy areas: more even T patterns (less variation).
- Clouds are most variable factor affecting Earth’s radiation budget due to ability to reflect and absorb part of the short wave radiation as well as being able to send back some of the long wave radiation.
46
Explain the location relative to large bodies of water.
- Land and water absorb and store energy differently.
- Land heats and cools faster than water = more T variations on land.
- Close-by large water bodies can store and slowly release large amounts of sensible heat: they moderate T oscillations.
47
1. Define continentality/continental effect.
| 2. Define maritime/marine effect.
1. Areas in the middle of large continents have larger daily and annual T ranges (further away from large bodies of water that moderate T variations through sensible heat).
2. Costal or island locations have more constant T, and and annually even if they have the same latitude as a continental part.
48
Define convergent lifting.
Air convergence into a low-pressure area, displacing air upwards.
For example, intertropical convergence zone.
49
Define convectional lifting.
Air mass passing from maritime source region to warmer continental region, heating from the warmer land causes lifting and convection in the air masses.
50
Define orographic lifting.
Physical presence of a mountain acts as. Topographic barrier to migrating air masses. Air is forcibly lifted upslope as it is pushed against a mountain, mountain is condensed from the lifting air mass on the windward side; on the leeward side, the descending air is heated by compression, remaining water evaporates, creating a rain shadow.
Windward side: warm and moist air.
Leeward side: hot and dry air.
51
Define frontal lifting.
Movement of warm, moist air mass above cold dry air mass.
52
Define interception.
- Capture of incoming precipitation on surface of vegetation before reaching the surface( where is sticks due to capillarity and evaporates during clear weather).
- reduces intensity and amount of precipitation reaching the ground. Loss of water to soils (less input).
53
Define through fall and stem flow.
Throughfall: Precipitation that reaches the ground, including drips from vegetation that are not stem flow.
Stem flow: rains that runs down branches and trunks of tree to reach the ground. Intercepted water that drains across the plant leaves and down their stems to the ground is known as stem flow.
54
What is a water budget?
Derived from measuring the input of precipitation and its distribution and the outputs of évapotranspiration - including evaporation from ground surfaces, transpiration from plants, and water runoff.
55
Define infiltration (high and low) and overland flow/surface runoff.
Infiltration: penetration of the soil.
- high infiltration rate: the infiltration rate of the soil is greater than the precipitation rate in rainfall. all water moves into the soil.
- low infiltration rate: precipitation rate is more intense than the infiltration rate = depression storage. Water will become overland flow.
Overland flow: if the ground surface is impermeable then the water will begin to flow downslope as overland flow.Overland flow ill occur if the soil has been infiltrated to full capacity and is saturated.
56
Define stream flow.
If overland flow remains in place on the surface in puddle or ponds, or may flow until it forms channels. Term that describes surface water flow in streams, rivers, or other channels.
57
Define percolation and soil-moisture zone.
Percolation: The slow passage of water through a porous substance.
Soil-moisture zone: Contains the volume of subsurface water stored in the soil that is accessible to plant roots. Within this zone, some water is bound to soil so that it is not available to plants.
58
Define gravitational water.
Water surplus within the soil body that will drain under the force of gravity, from saturated conditions, emptying the largest pores and percolating downward into the deeper groundwater.
59
Define field capacity.
Soil moisture left after draining of gravitational water (amount specific to each soil type: depends on pore sizes).
60
Define hygrospcopic H2O.
Inaccessible to plants, tightly bound to soil particles; unvailable to meet PE. At the wilting point, this is the only water present in the soils.
61
Define wilting point.
When only hygroscopic water remains. Plant transpiration shuts down.
62
Define potential évapotranspiration (PET) and actual évapotranspiration (AET).
PET: Amount of water that would evaporate and transpire under optimum moisture conditions (adequate P and soil-moisture supply).
I.E. maximum rate if water freely available.
AET: If we subtract the deficit (the amount of PE that is not met) from the PET.
GEOG 203
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