AUENV 231:Midterm #1

Geography

The science that studies the interdependent relationships among natural systems, geographic areas, society, cultural activities all over space

“geo” - earth

“graphein” - to write

a method not a body of knowledge

holistic, eclectic

uses: spatial analysis, systems science

Key geographic perspectives

1. Spatial: (where?) most important, locations and patterns (need maps)

2. Ecological: (why?) interrelationships among variables

3. Temporal: (when?) changes over time

What are the two sides of geography

physical (climatology, microclimataology, soil

human/ cultural (behavioural geography

Physical geography

the spatial analysis of all the physical elements and processes that make up the environment

System

ordered, interrelated set of things; linked;distinct from outside

They affect each other

Open vs. closed systems

Open - lots of things going back and forth Eg. Energy, water cycle

Closed - has some sort of boundary Eg. Matter because what matter we have on earth is what will be. underground caves that have their own ecosystem

Positive vs. Negative feedback

Positive - initial change is a slight push and it gets faster and faster. Eg. Albedo effect

Negative - initial change is subdued Eg. rivers ability to be resilient

System Equilibrium

everything is interacting in equilibrium

steady-state - lots of minor changes but it stays at the same equilbrium

dynamic - rapid change then finds a new equilibrium Eg. erosion in a river

metastable - stable for a while then finds a new equilibrium

Meteorology

study of the atmosphere and the processes that cause weather

Climatology

study of the weather elements over a long time

Weather

short-term conditions of atmosphere

Climate

long-term conditions (eg. 30yrs) of atmosphere (and variability)

Atmosphere

mixture of gas molecules, suspended particles, and falling precipitation

affects our day-to-day lives

Thickness of atmosphere

density increases rapidly with height

• majority of mass is compressed at the surface

• Top is undefined

• Because of gravity

<2% of earths radius

Density at sea level

1.2 Kg/m³

Composition of the atmosphere

gases and particles are exchanged between the surface and atmosphere

Processes: Carbon, condensation, evaporation, precipitation,

Most common gas is atmosphere is Nitrogen: ammonification, nitrification

Oxygen

Photosynthesis

Respiration - take in and release O2

Permanent gases

constant proportion of mass in time and space

Eg.

• Nitrogen (78%)

• Oxygen (21%)

• Argon

• Neon

• Helium

• Hydrogen

Nitrogen Cycle

Dynamic

released by volcanoes, released into atmosphere, captured by many different things

Density is highest where/

Closest to the earths surface

Variable Gases

Variable concentrations over time

Water vapour

CO2

Water Vapour

most abundant variable gas

hydrologic cycle

Concentration= 0%-4% of air

Important for energy balance and atmospheric processes

Carbon Dioxide

Trace gas

0.04% of air by volume

critical to earths energy balance

Adding processes - Wildfires, cellular respiration, driving

Removing processes - photosynthesis (can be locked away(stored in plant and buried underground))

Increasing by 1.8ppm/yr

Photo:

Temporal increases due to human activities

seasonal variations related to biological activity

Methane

0.0002%, but recently increasing

Increasing? burning fossil fuels, livestock digestionm and agriculture cultivation

Effective absorber of terrestrial radiation

• affects near surface warming

Ozone

3 atoms of Oxygen

absorbs ultraviolet radiation

chlorofluorocarbons (CFCs) destroy ozone

destruction over southern hemisphere

antarctic circumbpolar vortex

• limits latitudinal mixing: leads to an O3 “hole”

• It is getting thicker which is great!

What atmospheric gas has the largest residence time? what has the smallest residence time?

Largest: Nitrogen - 1,600,00 years

Smallest: Water Vapour - 10days

Ozone - hours to days

Aerosols (particulates)

airborne solid and/or liquid particles (not water)

• natural: sea spray, dust, combustion, volcanoes

• Human: combustion, industry

• Some long residence times

condensation nuclei: can change what is going on in the atmosphere. Assist with increasing precipitation. Huge clouds within communities with lots of condensation nuclei

Vertical structure of the atmosphere

Density

• mass (kg) per unit colume (m³)

• near surface air is more denseLay

  • compressibility

  • mean free path = avg distance before collision

    • at surface = 0.0001mm = high density → more friction

    • At 150km = 10m → higher mean free path

Layers of the atmosphere

Composition

• Homosphere (well-mixed), <80km

• Heterosphere (not mixed), >80km

Temperature

• troposphere, startosphere, mesosphere, thermosphere

Unique properties

• Ionsphere (aurora borealis), ozonosphere

Troposphere

goes from 15C to -60C, 10-15km

Rate is -6.5C/km. Exceptions is inversion when there is a layer of warm air over a layer of cold air. Can cause fog. Warm air holds down other layer of “smog”

Virutally all weather processes

• 80% of atmospheric mass

Stratosphere

-60C to 0C, 50km

Little actual “weather”

ozone layer (20km-30km), little moisture

Temperature inversion

• caused by absorption of UV radiation by O3

• 19.9 atmospheric mass

Stratopause

Mesophere

0C—80C, 70km

Coldest layer

Thermosphere

-80C → 0C, 90km

increasing temperatures

• molecular kinetic energy vs. heat content

Tropopause

Top of troposphere

Ionosphere

layer of electrically charged particles (ions)

• in mesophere and thermosphere

D-, E-, F-, increasing with height

Interactions with subatomic particles and they absorb radiation making colours. Aurora borealis (northern lights), aurora australis (southern lights)

Atmosphere Evolution

Primordial

• 4.6-4bya, hydrogen and helium, solar wind

Evolutionary

• 4-3.3 bya, volcanic outgassing, cloud, comets/meteorites

• H2O, CO2, chemosynthetic bacteria

Living

• 3.3-0.5bya, cyanobacteria, N2, O2 increases

Modern

• 0.5bya to present

  • life

Pressure

force exerted per unit areaW

Wind

horizontal movement of air

• caused by unequal pressures

• having a high pressure zone and a low pressure zone. Going from high to low

Volatile Organic Compounds

Photochemical Smog

NOx and OVCs accumulate during rush hour

• Reactions involving solar radiation transform these into ozone and other secondary pollutants

• Concentration are hghest in afternoons

  • most prevalent on clear days

Emission trends in Canada

Making good progress

Dealing with emissions and sources

• Fort McMurray tar sands helping

Conditions affecting dispersal of air pollutants

1. Dilution minimizes the damage caused by pollutants. Eg. Wind can help dilute

2. Faster wind leads to greater dispersal

• Transported downwind more quickly

• Increased turbulence causes vertical mixing

3. Wind and stability control the rate of mixing with clean air

• Stable atmosphere restricts vertical motion. Air doesn’t go up or down, which increases pollution

• Radiation or subsidence inversions (limits mixing)

4. Anticylconic conditions: contributes to poor air quality

• Light winds; sinking air and subsidence inversions

• no precip. to remove pollutants

• closed loop land-sea breeze circulations can develop

4. Topography: mountains trap pollutants in valleys and basins

Air quality assessment

• 300 air pollution moitring stations across Canada

• - mostly in urban areas

• Measure CO2, SO2, NOx, VOCs, O3, PM, and heavy metals

• Air quality Helath Index (AQHI)

• based on O3, PM, PM, NOx

• Canadaian Environmental Sustainability In

Depletion of Stratospheric Ozone

Ozone in troposphere is pollutant - want les of it

Ozone in stratosphere is a benefit bc it can absorb UV radiation.

Long-lived substances can circulate to the stratosphere and deplete ozone layer

• Choloroflurocarbons (CFCs)

Sun

Energy drives temperature variations

Affects atmospheric pressure. High to low pressure creates winds

Affects air movement and ocean currents

affects the weather and violent weather

Long-term patterns determine climate

affects plants, animals, soil, ecosystem, and humans

Energy

Ability to do work

Kinetic

Potential energy

• See energy as light

• Feel energy as heat

• experience it as movement

Law of conservation of energy

energy can never be created or destroyed but can be transformed from one form/object to another

Energy transferred in two ways

1. As Heat

• Conduction: transfer energy between molecules in contact. Eg. heating up a frying pan

• Convection: transfer energy by vertical motions of a fluid. Eg.

• Radiation: transfer by electromagnetic waves. Eg. From sun while tanning,

2. As work

Heat

energy transfered due to temperature difference

causes molecules to go faster

• kinetic energy of molecules increase

• temperatire is a measure of the avg speed of molecules

heat energy

Internal Energy: total energy contained in tehe molecules of a substance

Thermal Energy: kinetic energy of molecules, temperature changes

Potential Nergy: attractivce forces between the molecules. Phase changes (solids, liquids, vapour)

Sensible Heat

heat transfer that leads to temperature change

• object will feel warmer or colder

Substances warm by different amounts with equal heating

Q=mcT

Eg. asphalt has high specific heat, sand

Latent Heat

heat absorbed or released by a change in phase

• energy is transferred, but no temperature change

• temperature is hidden or latent

These processes absorb latent heat: melting, evaporation, sublimation

These processes release latent heat: freezing, condensation, deposition

Latent heat of vaporization

amount of heat involved when a substance changes between liquid or gas

Q=Lvm

Latent heat of fusion

amount of heat involved when a substance changes between Q=Lfm

Work

transfers energy by mechanical means

• Eg. person pushing a cart

Work is equal to force multiplied by distance

W=PV

Gases and Work

an expanding gas does work on its surroundings

• its internal energy goes down

COmpressing a gas requires work to be done on the gas

• its internal energy goes up

P, V, T

Increase pressure, Volume decreases → inversely proportional

Increase Temperature, Volume Increase → proportional

Increase temperature, pressure increases → proportional

First law of thermodynamics

ways to increase temperature of a a gas: add heat, add work

Both will increase the internal energy

Q = change in U + W = mcchange inT + P change in V

All heat transferred to, or from, a gas must be accounted for by a temperature change, work, or both

Constant Pressure

if air is unconfined, some of the added heat foes into expansion, resulting in an increase in temperature and volume

Adiabatic process

temperature change without heat ransfer

driven by a change in pressure

• expansion causes cooling

• compression causes heating

Presure always decreases with height

vertical movement causes adiabatic temperature change

Eg. Chinooks, air that has gone over mountains and has compressed and heating up

Diabatic process

temperature change caused by heat rransfer

Diabitic processes:

• conduction

• convection

• rasiation

• phase change

Some or all of these often opereate simultaneously

Conduction

transfers heat from molecule to molecule

• Faster molecules pass energy to slower molecules

• Conductivity is highest for solids

Laminar boundar layerboundary

layer of air that is in contact with ground

• it receives heat form conduction

• only a few millimeters thick.

Convection

transfers heat through moving liquids and gases

• heat is redistributed in space

Two types:

• Thermal (free convection)

  • driven by density difference

  • warm air is less dense and has a tendency to rise on its own

• Mechanical (forced convection)

  • driven by mechanical forces

  • mixing driven by winds and turbulence

  • Florida used big winds to save crops

Radiation

energy that travels in electromagnetic waveds

• eg. light waves, microwaves, radio waves

• everything emits and absorbs radiation

  • emission transfers energy out

  • absorption trnsfer energy in

  • Hotter substances emit more radiation than cooler ones

Daytime vs. nightime

solar radiation warms the surface

• some heat is transferred upwards from the surface to the atmosphere and downwards into the ground.

rasiation emission cools the surface

• some heat is transferred downwards form the atmosphere to the surface an upwards from the ground

How has Aurora borealis been viewed/ interpreted as in the past

Inspiration: poetry, light show, art

Predictors: borth, death, end of worls

Warnings: illness plague, death

Evidence of battle or games

Aristotle: flames of burning gas

• “jumping goats”

Biblical (Ezekiel): Visions of God

Greeks: Apollo the sun god

Greenlanders: Glacier God

Chinese: Predict important events, rarely got them so this is why

Vikings: Evidence of battle

Estonia: Wedding in the sky; guests arrive on the sleighs lit up

Maori: ancestral travelers in cold zones

Australian Aboriginals: feast fires of dream circles

Inuit on aurora borealis

heavenly lights sent by ancestors

guide way for newly dead

visit to moon

game of kickball

Nothing new:

Walt Whitman

careful to know too much

More fun to have interpretations

early theories

firelight reflected from edge of world

sunlight reflecred form arctic ice

sunlight relfected off ice crystals in sky’volcanic eruptions

electricity in clouds

Sunspots

temporary dark regions on tehe sun caused by large magnetic disturnbaces

• 11 year cycles

Solar flare

a solar disturbance with intense hot flashes

• last only for minutes

Magnetosphere

magnetic field surrounding earth

• north and south pole

generated by dynamolike motions in earths outer core (molten metals)

• protects earth, deflects solar winds

Like a really hot goalie. Weak spot for each goale and that is the north and south pole for this

Solar wind can enter at weak points

• polar regions

• solar wind (ionized particles) collides with gases in upper atmosphere

• gases absorb and then emit energy in the form of visible light

Auroras

Locations

• borealis - northern lights

• australis - southern lights

Molecules

• H2: red, H: green

• N2+: blue/purple, No: pink/purplish

Always present, even in daytime. most visible in auroral zone

Yellowknife is best place to see northern lights (243/365 days)

Possible relationships with earth

drought periods coincide with solar minima (few sunspots)

wet periods coincide with solar maxima (more sunspots)

Air pollutant

any substance in the atmosphere that can negatively impact health

Primary vs. Secondaey Pollutant

Primary → emitted directly into the atmosphere

Secondary → forms in the atmosphere as a result of chemical reactions

Types of Air Pollutants

Carbon Monoxide: a toxic gas from incomplete combustion of carbon-based fuels

Sulpher Dioxide: contributes to acid deposition from coal burning, smelters, pulp mills

Nitrogen oxides: contributes to acid deposition through high temperature combustion

Volatile Organic Compounds (VOCs): smog, from evaporation of fuels and solvents

Ozone: eye and lung irritation, vegetation damage, from evaporation of fuels and solvents