1
Q
what are earths 4 systems
A
- atmosphere: air from porous soil to 10k km above earths surface, protects from radiation, weather
- hydrosphere: solid, gaseous, and liquid water –> 10-20km thick, mostly salt water
- lithosphere: solid outer part of earths crust, petosphere (soil) links litho and hydro)
- biosphere: all living things from microorganisms to plants & animals, biomes
2
Q
what is an environmental system
A
system: any ordered interrelated set of things linked by flow of energy or matter e.g. lake and watershed, earth and sun –> boundary based on concept
3
Q
what is an open system
A
not self contained, inputs –> actions (stored or converted) –> outputs
e.g. car input (gas) –> action is movement –> output (exhaust)
earth is a open energy system
4
Q
what is a closed system
A
rarely found in nature, self contained e.g. earth is a closed matter system
5
Q
what is a transient system
A
when inputs and outputs are out of balance
–> inputs > outputs or inputs < outputs = change in storage
6
Q
what are some attributes of environmental systems
A
function: structure & fluxes e.g. open/closed
scale: size in time & space (depends on how you draw the boundary)
feedbacks: positive or negative
equilibrium states: does the system return to ‘normal’
7
Q
what is a positive feedback
A
encourages changes to the system e.g. ice albedo feedback or permafrost thaw
snowballing effect
8
Q
what is a negative feedback
A
discourages changes e.g. predators provide negative feedback for rampant prey population
stabilizing effect
9
Q
what is equilibrium state
A
system maintains structure & character over time
10
Q
what is steady state equilibrium
A
inputs = outputs & amount of energy/matter in storage stay constant over time (fluctuate around average)
e.g. water storage in large lake
11
Q
what is dynamic equilibrium
A
inputs > or outputs > (there is a change in storage), but the system is adjusting to the trend over time
e.g. rising CO2 in earths atmosphere
12
Q
how can system stability be affected by feedbacks
A
stable state: negative feedback dominates
unstable states: positive feedback dominates
equilibrium states: stable through troughs unstable through peaks
13
Q
what is a regime shift
A
when unstable feedbacks are overwhelmed and the system shifts to a new state
14
Q
what is a threshold
A
a point where the system switches to a new equilibrium
–> metastable equilibrium
e.g. climate events like melting sea ice are considered threshold events
15
Q
what are the different types of threshold events
A
cyclical events: e.g. seaonal variation in atmospheric CO2
episodic events: e.g. volcano erruption
16
Q
what is electromagnetic radiation
A
any matter above 0 degrees kelvin (-273 degreesC) emits radiation –> characterize by wave length & amplitude (height)
17
Q
what is the electromagnetic spectrum
A
from short to long: gamma –> x rays –> UV rays –> visible light –> infared –> thermal infared –> microwaves –> radio waves
18
Q
what are the 2 radiation laws
A
- weins law: hotter objects emit shorter wavelengths at peak radiation
- stefan-boltzman law: hotter objects emit more
19
Q
what are the 3 things that happen to the suns SWR
A
- transmission: visible light more than UV
- reflection: albedo is reflectivity, light objects reflect more
- absorbtion: depends on wave length
20
Q
what is the solar constant
A
avg value of insolation when earth is avg distance from the sun –> 1370 W/m2
b/c earth is rotating sphere our solar radiation receipt is 342 W/m2
21
Q
what are milanovitch cycles
A
long term changes in the ammount of radiation hitting earth
eccentricity: earth encounters more variation when its orbit is elongated
tilt: between 22.5-24.5 –> over long periods of time, reason for ice age
precession: gradual wobble in orientation of earths axis affecting tilt & eccentricity
22
Q
why do we experience seasons
A
not due to distance, but due to earths axilial tilt
warmer days result of higher solar altitude and longer days
23
Q
what is earths rotation, revolution, and tilt
A
revolves on plane of ecliptic around the sun, rotates 24 hrs in day –> tilt is 23.5 degrees off plane of ecliptic
24
Q
what is the subsolar point
A
a.k.a. solar declination –> single point where suns rays are perpendicular to earths surface @ or near noon –> doesnt happen in mtl
25
what is the circle of illumination
line seperating night from day where sunrise & sunset occur
26
what is solar altitutde & how do you calculate it
how high the sun is above the horizon --> 0 degrees = on horizon, 90 degrees = directly overhead
-->90 degrees - local latitude
27
what are the 4 seasonal markers
1. september equinox: sept 21-24, equal day length across globe, subsolar point = 0 degrees
2. december solstice: dec 20-22 SSP = 23.5N
3. march equinox: mar 19-21 SSP = 0
4. june solstice: june 20-22 SSP = 23.5S
28
what is the atmosphere
envelope of gases that sorround earth
29
what is the karman line
widely accepted definition of the top of the atmosphere --> 100km up
30
what are permanent gases
composition doesnt change much --> 78% nitrogen & 21% oxygen --> 99% total
31
what are variable gases
small quantities & change over time --> greenhouse gases: absorb & emit heat (thermal radiation) H2O, CO2, methane (CH4), nitrous oxide (N2O), ozone (O3), CFCs & HFCs
32
what is the atmospheric window
% of radiation absorbed during vertical passage through the atmosphere
33
what is air density & pressure
deeper you go higher the pressure
density = amount of gas molecules in given volume
pressure = weight of atmosphere after a certain point
34
what is the troposphere
90% atmospheric mass, most weather, temps decrease w height
environmental lapse rate: rate of cooling, 6.5 degreesC/km up
35
what is the stratosphere
where ozone is absorbed, temps increase w height --> contains ozonosphere, more horizontal weather systems
36
what is the mesosphere
temps decrease w height, coldest level in the atmosphere, where meteors occur
37
what is the thermosphere
temps increase w height, hottest part of atmosphere (even tho it doesnt feel like it), contains ionosphere where gamma, x-rays, and UV is absorbed
auroras in this part
38
what is the greenhouse effect
without greenhouse gases earths radiating temp would be -18 degrees, but the avg temp is 15 degrees, the difference of 33 degrees is the greenhouse effect --> increased CFCs & HFCs increase greenhouse effect
39
what was the ozone hole and the montreal protocol
80s & 90s hole in ozone layer appears especially around the poles --> montreal protocol successfully bans CFCs and HFCs --> now ozone hole expected to close within few decades
40
what are the solar energy pathways
1. transmitted: unimpeded movement, most visible light
2. scattering: redirection by gas molecules without changing wave lengths (colors)
3. refraction
4. reflection: (albedo) energy that bounces off surface but doesnt provide heat
5. absorbtion: molecules take in and convert radiation from one form to another
41
what is albedo
% of received short wave that is reflected
= (SW reflection / SW absorption) 100
snow, ice, clouds have high albedo
ashpalt has low albedo
42
what is the global radiation budget
inputs of SW from the sun & outputs of LW radiating from earth
net radiation (Q*) = SW in - SW out - LW out
342 - 107 - 235 = 0 net radiation --> planetary Q* balanced in the long run
43
what does the sphericitiy of earth do to insolation locally
tropics 2.5x more insolation --> surplus at equator & deficit at poles creates earths currents & winds
44
what is the radiation balance at earths surface
Q* = SW in - SW out - LW out + LW in --> consider thermal infared radiation that comes back down to earth --> most is then converted to sensible or latent heat and reflected back out --> why earth isnt constantly warming
45
what is the surface imbalance in the net radiation absorbed and what does it cause
0.6% W/m2 --> now at 1.8% --> greenhouse gases trap residual which is causing earths temperature to warm --> mostly oceans warming, surface temp has to warm until balance btwn incoming & outgoing radiation is restored --> why climate change
46
what is the daily radiation curve
insolation at certain location --> peaks at noon, but lag in temp
47
what are the 3 other forms of energy that Q* is partitioned into
Qe: latent heat Qh: sensible heat into atmosphere Qg: conduction into the ground
48
what is sensible heat v.s. latent heat
sensible heat: transfer sorrounding bodies are heated e.g. lake temp goes up, Qg is sensible type
latent: uptake and release of energy as water changes from solid to liquid to gas (evaporation)
49
what are 2 examples of how different surfaces deal with their surface energy budget
pitt meadows BC (forest): well watered, expends mostly latent heat
dry desert: mostly sensible heat followed by ground heat
50
what is heat transfer and the ways it occurs
heat moves from areas of high heat to low heat --> follows energy gradient
1. conduction: molecule to molecule transfer e.g. touching hot handle
2. convection: transfer by movement through gas/liquid e.g. bubbles in boiling water
3. advection: horizontal movement of warm air e.g. wind
4. latent heat: energy released/absorbed during transition from one phase to another e.g. evaporation
51
what are major patterns based on geography for latent & sensible heat
latent heat: oceans > land --> lowlands > mountains & forests > grasslands > deserts
sensible heat: equator > poles --> land > oceans --> deserts > grasslands > forests
52
what is air movement driven by
driven by gradients in pressure horizontally from high to low pressure --> visualized by isobars --> equator = low pressure, poles = high pressure
53
how are wind directions named
from where they come from e.g. westerlies come from west to east
54
what are the 3 forces that control wind speed & direction
1. pressure gradient force: from changes in barometric pressure
2. Coriolis force: due to earths eastward rotation
3. friction force: important near earths surface where frictions strongest
55
how does pressure gradient work
, colder denser air moves wind away to low pressure hotter air --> the greater the pressure difference between regions, the faster the air will flow
56
how does coriolis force work
deflects objects traveling in the atmosphere, --> objects in north deflected right, objects in south deflected left
-- alters direction of object but not speed
--deflection is 0 at the equator & increases w increasing latitude
-- low pressure systems: counterclockwise in north, clockwise in south
-- high pressure systems: counterclockwise in south clockwise in north
57
how does friction force work
diminishes at 1000-1500m high, causes wind to slow down & move in irregular ways
low pressure system: spin inward e.g. big clouds & storms
high pressure system: spiral outward e.g. clear day
58
what is the combined effect of all 3 forces
wind spirals out of high pressure cells (anticyclones) and into low pressure cells (cyclones)
59
which direction do cyclones & anticyclones spin
cyclones: low pressure counterclockwise in north clockwise in south e.g. hurricanes
anticyclones: high pressure clockwise in north, counterclockwise in south
60
what are the 4 global pressure belts
1. intertropical convergence zone: band of thermal low pressure & thunderstorms at tropics --> because of strong solar heating at equator unstable air parcels rise up with convective lift and regional convergence --> latent heat enhances this instability
2. subtropical high: belt of high pressure and aridity made up of anticyclones at 30 degrees north and south --> because air moving poleward from the ITCZ is redirected downward and sinks --> creates major deserts
3. subpolar low: about 60 degrees N/S, dynamic low pressure cycle that causes cyclonic systems of frequent precipitation (e.g. montreal)
4. polar high: cold dense air forming zone of thermal high pressure similar to subtropical high --> creates polar deserts
61
what are the 6 global wind patterns
1. trade winds: starts at 30 degrees flowing towards equator deflected by coriolis effect
2. westerlies: start at subtropical high flows towards poles and gets deflected
3. polar easterlies: cold air flowing away from poles deflected by coriolis force
4. upper atmospheric circulation: high P diverge at surface & converge higher up, low P converge at surface and diverge higher up
5. upper level westerlies: high altitudes, air flows toward the pole from 30 degrees and is deflected
6. antitrade winds: at high altitudes air flows towards the pole from the equator and is deflected right
62
what are the 3 circulatory cells
1. polar cell: polar jet streams flow in & westerlies flow out
2. ferrel cell: at subtropical high
3. hadley cell: subtropical jet streams flow out and trade winds flow in
63
what are ocean gyres
circular gyres in big oceans moving warm and cold water --> clockwise in north and counterclockwise in south
64
what are surface ocean currents
reflect high and low wind pressure systems --> effect 10% of oceans water
65
what is thermohaline circulation
deep ocean currents driven by changes in temperature & selenity --> cold salty water sinks & warm less salty water rises --> 90% of ocean effected --> important to transfer heat from equator to northern hemisphere
66
what is the el nino southern oscillation
warming surface waters due to weakening trade winds causing less rainfall over western pacific (like indonesia) and causing more rainfll over the central and eastern pacific
--> la nina is opposite effect
--> every 3 - 7 or 8 years, warmest years on record are el nino years
67
what is the pacific decadal oscillation
10-30 years --> positive phase of warmer south east pacific & cooler north west
negative phase of warmer north west cooler south east
68
what are the north atlantic and arctic oscillations
linked, happen in phases due to pressure differences at the arctic
positive NA: strong low over iceland, strong high over subtropics (stormier north west europe, drier south surope)
negative NA: polar vortex weather with up and down jet streams
positive A: strong polar high, tight jet stream moving northwards
negative A: meandering jet stream w warm air moving north & cold air moving south
69
define temperature
measure of kinetic energy of molecules experienced as sensible heat --> use degreesC or Kelvin scale
70
define heat
energy transferred between materials or systems due to temp differences
71
what are the 5 controls on temperature
1. altitude: higher cooler & bigger day night variance due to thinner atmosphere & surface gaining & losing energy more rapidly
2. latitude: higher = cooler & more seasonality
3. presence of water: maritime v.s. continental effects
4. cloud cover: cloudy days cooler, cloudy nights warmer
5. prevailing winds: west coast have more maritime effect than east coast --> pattern is strongest at midlatitudes
72
what are the 5 reasons that presence of water effect temperature
1. evaporation: latent heat = cooler temps
2. transparency: insolation penetrates water which heats more than land
3. high specific heat: water gains & loses heat more slowly (moderating effect, heat sink)
4. movement/mixing: ????
5. ocean currents: heat from ocean transferred to atmosphere, warm currents raise avg temp & reduce temp range e.g. halifax & bordeaux at same latitude but bordeaux is warmer due to western gulf stream
73
what is the global distribution of water
97% ocean, 2.8% fresh --> 77% surface (99% ice, 0.33% lakes) 11% groundwater
74
what is the global hydrological cycle
evaporation --> clouds --> precipitation --> surface runoff/ground water flow --> oceans
closed budget cycle
75
what is a watershed
catchment/drainage basin --> basic landscape unit drained by a river system --> open system
76
what is the water balance equation
P = ET + R + ^S
P = precipitation, ET = evapotranspiration, R = runoff, ^S = change in soil moisture
77
what are the typical interception values based on plant type
spruce/fir 30%, birch 10%, grass 5%, moss 50%
78
what are the pathways of precipitation
1. interception: water on surface of vegetation
2. throughfall: precipitation that meets ground
3. stemflow: rain runs down branches & tree trunks to reach ground
79
what is evapotranspiration
transpiration from plants & evaporation from ground --> controled by availability of surface to give up water
80
what is potential v.s. actual evapotranspiration
potential: amount under optimum moisture conditions --> healthy full cover foliage & no lack of soil water --> measured thoretically
actual: less than potential --> AET = PET - deficit, limited by soil water availability --> ET reaches 0 at wilting point --> measured by evaporation pans, soil lysometers, eddy covariance
81
what are the controlling factors of PET and how do they work
mean temp: warmer evaporates more
humidity: humid ET less
radiation: longer days ET more
wind: windy days ET more
82
what is infiltration in the soil moisture environment & overland flow
infiltration of water into the soil (fastest at start of rainfall) --> if P > infiltration, overland flow
compact (arid) soil: low infiltration high overland flow
undisturbed (humid) soil: high infiltration, low overland flow
83
what are the soil characteristics
texture: low to high infiltration
land use: poor grazing = lower infiltration
status of vegetation & litter lays: breaks raindrop impact
84
what is soil moisture
volume of water in subsurface soil-moisture zone that is accessible to plant roots
85
what are the 4 levels of soil moisture
1. gravitational water: water draining from saturated conditions emptying in largest pores (not available to plants)
2. field capacity: soil moisture left after gravitational water has drained, dependent on soil type
3. capillary H20: accessible to plant roots
4. hygroscopic H20: inaccessible to plants, tightly bound to soil particles, cant meet PET --> wilting point
86
how does particle size effect soil moisture level
area between field capacity & wilting point is available water
sand: largest particles = low field capacity & wilting point, little available water
silt/loan: medium pores = goldilocks zone
clay: smallest pores = high field capacity & high wilting point, little available water
87
how is the soil water budget effected by season
P > E in winter with low temps --> soil water budget is higher
P < E in summer with higher temps, deficit period
88
what is percolation
rainwater infiltrating downwards to underlying rock --> groundwater
89
what does a water table display
divides saturated & unsaturdated rock & soil --> follows landscape, perched water table shows pockets of groundwater under impermeable rock layers (confined aquifors) which can be really old and are used for irrigation
also shows active springs where groundwater emerges at surface
90
what is a gaining v.s. losing stream
gaining: base flow is partially supplied by high water table w ground water feeding the stream
losing: supplies lower water table where stream loses water to sorrounding subsurface (drier climates)
91
what is runoff
surface-water runoff, subsurface throughflow, or groundwater movement beneath water table --> travels to perennial (year-round) or intemittent streams
92
what are the 2 types of overland flow
horton/precipitation excess: rainfall intensity > infiltration capacity
saturated: soil becomes saturated so all rainfall becomes overland flow
93
how do you measure the discharge of a stream or river
Q = velocity x area
can also find depth
hydrograph: time series of discharge at single point along stream
94
what is the global mean precipitation pattern like & what is runoff like in global areas
P: high at ITCZ, very little at 30 degrees, higher at 60 degrees, little at polar deserts
R: highest near equator, lowest near subtropical deserts, rain-shadow areas, and continental interiors
95
what is the runoff coefficient and what is it effected by
R/P --> biome e.g. tundra has high R coefficient despite having low P & low R while tropical rainforest has high R coeff while having high P and high R
land use e.g. forest lowest and pavement highest
96
how does storm type & catchment characteristic effect runoff
small, steep, bare & impermeable soil catchments have more dramatic responses to large and small storms than large, gentle slope, forested, and permeable catchments
97
what is an example of an experiment where deforestations effects on hydrology were tested
hubbard brook catchment: control watershed v.s. treatment watersheds --> showed clear cutting & herbicide caused more runoff than whole tree harvesting and no treatment --> system responded quickly & eventually regrowth in treated catchment caused less runoff than untreated
--> found 25% of total tree area needs to be cut to increase runoff
98
what are the 3 hydrological effects of deforestation
1. reduced interception: more water reaches soil surface
2. less transpiration: fewer roots & higher evapotranspiration causes greater runoff
3. changes in flowpath: greater through & overland flow leads to flashier hydrographs
99
how does deforestation influence Q*'s different components
Qe (latent heat) down, Qg & Qh go up
LW out increases w higher albedo
Q* drops
less cloud cover & precipitation
100
what is an urban heat island
warmth of urban areas compared to non urban areas --> measured by difference btwn max urban temp & temp of sorrounding rural area --> nighttime phenomena, well known, tracked by sattelite imagery
101
what is the urban energy balance
Q* + Qf = Qh + Qe + ^Qs
Qf = energy flux density released by human activity
^Qs = heat storage in ground, buildings, air, vegetation
102
what are the hydrological effects of urbanization
1. precipitation increas of abt 10% due to cities drawing in warmer air which form clouds
2. decrease in ET rates w less water availability
3. increased runoff due to impervious areas which increase overland flow
4. increase subsurface flow & lower water table due to sewage systems
--> overall increased peak runoff (floods) & decreased low flow runoff
103
what are potential solutions to the hydrological impacts of urbanization
regreening & stop paving over rivers
104
what are the altered heat energy terms from UHI
increase LW in (aerosols increase reabsorbtion)
increase SW absorbtion (canopy geometry --> buildings)
decreased LW out (canopy geometry)
increase storage heat flux (^Qs) due to building/paving materials
decrease evapotranspiration (Qe) due to impervious surfaces & increased sensible heat (Qh)
105
who is most vulnerable to UHI
lower income people, vulnerable populations (<5, >65, socially marginal) --> all exacerbated w global warming
106
what are 4 strategies to conbat UHI
1. increase surface albedo (white roofs)
2. reduce heat loss from buildings & vehicles
3. install air conditioning
4. increase biomass (green roofs)
geog 203
flashcards
Decks in class (3)
# Cards
