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113 Cards in this Set
- Front
- Back
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30 % of radiation from the sun is lost to
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latent and sensible heat
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Most of heat transfer is governed by
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greenhouse factors
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w/o greenhouse effects the mean temp would be
the present mean temp is |
-17C
15C |
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climate change due to changes outside the system
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short wave radiation
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climate change between components within the system
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ocean currents.
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most climate change is due to variation from
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within the system
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principle components
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atmosphere, land surface, oceans, cryosphere, biosphere
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time of change:
atmosphere earth surface oceans cryosphere biosphere |
hours
days weeks to centuries centuries+ varies widely |
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positive feedback
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glaciations and albedo leading to icehouse world
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negative feedback
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greenhouse and oceanic CO2
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critical thresholds, that when crossed induce rapid change
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freezing point:
albedo, flow, evaporations |
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chaos
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imperceptibly small variation may lead to large and unpredictable changes
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componets of the atmpshere
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troposphere is all we are concerned with
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differential heating leads to high and low pressures
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convection(hot air is light)
quasi stable pressures winds hadley circulation - monsoons |
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moisture effects move heat energy and rain
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latent heat loss, significantly more important than sensible
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ITCZ
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intertropical convergence zone
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heat transfer that is a major focus of paleoclimates
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polar heat transfer, related to the movement of the itcz
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what shifts with the itcz
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tradewinds
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poleward heat transfer has an effect on
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storm track, latent heat transfer, and ocean circulation
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ocean surface currents are driven by
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wind+corriolis
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eckman flow
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net water movement at 90 degrees to wind
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deep currents are driven by
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thermohaline properties, (massive bank of heat energy, largest store of available CO2)
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Earth surface changes at 2 scales
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short term, and long term
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long term are affected by climate
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continent position, mountains (wind/rain), erosion, weathering
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cryosphere
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long term effects on climate, and responds slowly to climate change
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cryosphere processes
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albedo, water sequestration(continental glaciers), thermohaline circulation(salt starving)
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biosphere affects 2 climate processes
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carbon cycling, albedo
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how we know it's our CO2
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coincident with industrial revolution, global aleration in carbon isotopes, loss of O2, Suess effect
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best seen in suess effect
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large quantities of dead carbon added to atmosphere, seen in sequential 14C measurements, msked by bomb radiocarbon
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other greenhouse gases being added
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methane- stronger but short 1/2 life
water- complex |
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As CO2 levels increase, the impact of further CO2 additions is
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diminished
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We need more data (more time)
lag times make it |
tricky
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In order to better understand the fundamentals we need better models, which will
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take a great deal of time
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what make it difficult to calculate the doubling of time since industrial revolution
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economic and technological uncertainties
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Major impact would rely on
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massive feedbacks like end of thermohaline circulation or methane hydrate dissociation
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what would a warmer world be like?
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sea level, extereme weather
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parameters we measure
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temp, precipitation variability,
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proxy (climate science)
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agency or function of a deputy
a measurement of a climate variabe that is made through a consequence of that variable |
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temp and rainfall affects the growth rate of trees,
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by measuring rings we infer past climate
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quaitative
quanitative time series discreet |
-general conditions
-precision limits, numerical data -continuous measurement of a variable -"snapshot" of past conditions |
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proxies commonly used
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ice cores, sediment cores, skeletal chemistry, fossil biogeography
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common thread is need for
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age control
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dating
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sratographic, radiometric, skeletal,
absolute, relative, internal chronologies |
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by studying modern systems we can
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quantify temp relationships and apply them to the past
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isotope systems
-O -H -C |
temp and water properties
water properties metabolism and dating |
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Delat values
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(sample-standard/standard)*1000
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light isotopes have a higher vapor pressure, thus vapor is composed of
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lighter isotopes than the fluid it evaporated from
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condensation will favor
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heavy isotopes
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as it gets colder there is more condensation, thus more lighter isotopes left in vapor
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-positive correlation with atmospheric temperature
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delta18O is a function of
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temp at the time of crystallization, and the oxygen isotope content of the fluid from which the crystal grows
negative correlation with temp |
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detailed proxies help model
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short term events
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show a collong event after the end of the LGM
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pollen cores, dryas tundra plant
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heinrich cycles
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periodic conglomerates in N atlantic deep ocean cores, (ice transport)
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bolling allerod interstidal
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abrupt warming 14,000 bp
slowed thermohaline circulation |
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if thermohaline is altered then
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heat reservoirs shift
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ENSO 3 factors
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SST/ upwelling
atmospheric pressure precipitation |
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SST/upwelling
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east pacific warming west pacific colling, thermocline deepens in the east
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atmospheric pressure
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equatorial pressure reversal, trade winds slow or reverse
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precipitation
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reversal conditions, as in rain in the desert
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warm
cold |
el nino
la nina |
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NAO
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shifts in high and low pressure centers, postive is lower pressure higher in the Atlantic, negative is southward displacement of these centers, teleconnections
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teleconnections
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impacts distal to the zone of initial change
all of these cycles have global impact, |
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moranes
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evidence of glacitations, ice age, conglomerates are deposited in mid atlantic, calve off deposit stones and gives us spatial understanding of how this occurs
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how do we know the paleolatitude of a rock
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magnetic field, gives us images of aincient continent positions
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ocean core dating
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characterizing by foramanifera
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O isotopes give us huge swings
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glacial periods(less water)
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glacial ice
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accumalted snow, evaporationf of sea water and putting it on land
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less ice = change in
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O isotopes
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water weight:
gulf of mexico cloud river |
0
-5 -7 |
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oxygen isotope line wiggles because of
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amount of ice
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through evaporation the glaciers are selectively taking the light isotopes
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and they stay there
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The hotter the crystal gets a sit grows,
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the more negative the value gets, more lighter isotopes preferentially get taken in
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take a crystal, put its isotope chem in equation to solve the
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temp it was formed in
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single most important proxy
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isotopes
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SMOW
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standard mean of ocean water
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measure sample, compare to standard. multiply by 1000.
gives weight of |
oxygen that oxygen molecule
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less than 0
greater than 0 |
evaporated seawater
water that has suffered evaporation |
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ice becomes more abundant, we sequester more light isotopes, thus ocean water becomes
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heavier
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triple variable problem
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measure sample
infer the salinity and temp that it formed at!!!!! |
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O isotopes have a negative correlation with
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temp
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measure preferential clumping of heavy isotopes, tells us
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temp of surface water. still experimental in geochem
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2 variables that govern o isotope value
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temp and weight of water
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temp goes up
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O isotopes go down
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heavy water
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high 18 O values
-one unit change of water value = one unit change of delta O 18 |
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mixing of fresh and salt water and evaporation
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govern water value
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delta O 18
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essential to understanding past clmates
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geochem finger prints used to track
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deep ocean water currents
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indirect measure ment of past climate
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proxy
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LGM
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18000 yrs ago
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past 10000 yrs
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holocene
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detailed proxies expose
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short term climate events
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climate change when demonstrated on graphs is surprising
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episodic, spiky
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ice records and corals help us figure out
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salinity, also we can determine depth they grow in based on type
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date coral by what element
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uranium,
therefore we can infer sea level from these 2 sources of data anout coral |
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bomb sequence
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follow radiation around the world and use it as a tracer
-ocean circulations and wind patterns |
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salt evidence
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2 part story of climate and tectonics
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salt waters that have receded
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leave strand lines, which can be dated by carbonates that might contain uranium
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thermohaline shutdown
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glaciers stop melting, worlds climate is like when glaciers were growing
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thermohaline shutdown( disruption of pole to equator circulation) creates
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climate chaos
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holocene climatic optimum
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many parts of the world grew comfortable warm, civilization
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reference points are from
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europe and North america. global extent of these things are poorly understood
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coupled system (ENSO and NAO)
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trade wind, hot water off coast of SA
weak counter current get super strong named and first observed by fishermen off peru happens around december low pressure zone la nina currently represented by a seasurface temp gradient |
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CTD
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device used in ocean to measure conditions at different depths
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chemical signal of upwelling is characterized by
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radiocarbon
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ways to use stable isotopes to measure sst:
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calcium carbonate off the edge of Austrailia
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Mg:Ca St:Ca
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pure temp proxies, correlated to salinity,
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salinity is a factor of runoff
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thus we can relate it to precipitaiton and evaporation
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corals mollusk, foram are used to determine
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sea surface gradient, which could determine past el nino cycles
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cold water in oceanic areas indicate
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upwelling
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we want to understand ENSO, NAO
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on a timescale oscillation
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3 things that govern climate
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diurnal cycles, seasons, lanina elnino
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before we understand global warming we must understnad
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nina/nino
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SIGNAL FROM NOISE
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SIGNAL FROM NOISE
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