ice on the land

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What are the direct impact and indirect impacts on cliamte of ice?
direct- ablation and accumulation on glaicers, greenland, antartica, and sea ice, indirect, role of surface meltwaterin controllling ice and role of ocean circulation
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What happened to the maritime glaicers in europe, norway?
maritime glaicers advances 1980-2000 and then retreated and is linked with strong positive north atlantic oscillations causing increased westerlies and accumulation
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What happened to the one in new zealand?
mid 1980- glaicer advances and then retreated from 2000, linked to enso (el nino southern oscicalltion) and IPO(interdecadal pacific oscillation),increased westerlies and accumulation
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What happened in greenland?
mass balance change, increase in ablation in coastal areas and more accumulation higher up, a negative overall mass balance, as accumulation odesnt affact ablation, thinning because not in balance
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What happened in antartica?
most of antartica is insensitive to small atmospheric temperature changes, on the peninsula mean temperatures are higher, leading to increased ice retreat, and thinning at the northern end of penisula south shetland islands
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What is happening to sea ice extent in arctic ?
in the artic, sea ice extent is decreasing due to global warming and natural variability, water has a igh speicifc heat capacity long time to warm up but hard to loost it
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What is happening to sea ice extent in antartica?
sea ice is not decreasing, but increasing slightly , polar amplification is not as strong
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where can surface metlwater flow?
on top of the ice (supraglacial), if it gets in a carck i can make it lubricant and make it flow quicker(cause ice shelf collapse), ifit moves in the ice it is englacial and below subglacial(increase velocity)
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what is the greenland zwally effect?
surface meltwater drains thgouh moulins(vertical shafts in the glaice caused by water going down cracks) to the base of the ice where velocity is increased
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What effect does ice shelf have on the antartica peninsula?
ice shelf breakup caused by surface neltwater weakening the ice shelf, ice shelves support glaical streams so if they collapse, glaicer thins and speeds up
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How does wind have an effect?
alters ocean circulation, wind blows from hgih to low pressure and differences are due to temp differneces
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What effect has the west antaetic ice sheer caused?
a large area of it is below sea level and is where it is most vulnerable to changes
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what is elastic rebound and reverse slope for west antaetica ice sheet?
pressure in the middle is created by pulling on either end of ice sheet, whcih causes it to slife quickly which creates a reverse slope, mIH has proved could raise sea level by 3m, grounding line retreats across a deeping bed, thickness and discharge
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what has happened to the pine island glacier and thwaites glacier?
main ice streams draining into this section called amunsedn ice streams, with deep reverse slopes and no large ice shelf, rapid thinning on these and velocity increase, grouding line has retreated
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what is the name of the intrusion of water which auses high melt rates and cuases the grounding line to retreat and surface to thin
circumpolar deep water (cdw)
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describe the marine ice sheet instability hypothesis
increased temp, increase melting and increased abltation, glaicer thinning, ice shelf thinnning, ice shelf collapse and removal, increase basal meltingof ice shelves
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what is the positive feedback loop for this?
increased calving/melting at base of ice sheet, glacier acceleration, thinning, grounding line migration, glacier situated on reverse bed slope, glaicer in deeo grounede water, increase in thickness
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Tell me about the pine island glacier?
accleration event in 1994, more CDW on contintal shelf coinciding with velocity icrease driven by changes in the wind stress, amunsden sea was further south and west in 1994 and caused intrusion of cdw, basal melting increase, ice& stress decrease
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what was the name of the project that showed a sediment core beeath an ice shelf and suggets obliquite oscillations?
andrill project
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why could fresh water disrupt theromhaline circulation
salinity of the water is an important driving force, it prevents deep water formingand stops the driving force
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what is the recent glacial period called and when was the last glaicial?
holocene, 15000 years ago
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What did warming in the past allow?
vineyeards to grow and vikings to colonise the ice free areas and they could grow crops
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what is permafrost?
frozen ground divede into multiple layers, ground surface, active layer,supra-permafrost layer, supraperfrost and talik, permafrost table, closed talki, intra permafrost talik and sub permafrost talik and unfrozen ground
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what are the types of permafost?
mostly found in northern hemisphere, continous, pervasive permafrost beneath the active layer, discontinours continiuiyof permafrost broken by taliks, sporadic, isolated blocks of thin permafrost
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what is the name of the ice which has melted which is left from permafrost?
thermocast,when rot it causes methane, which incerases global warming
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how does ice vary within the seasons?
melting is faster in spring than autumn, contracts slower in winter, these balance each other out but over time you get acceleration.
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what is the prediction of rcp 8.5 to be?
high base line of ghg, medium cropland and pasture area of agricitural area and medium-high pollution and glaciers will contribute most to sea level
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what is the prediciton of 6 to be?
med baseline or some mitigation, medium cropland, very low pasture and medium pollution, glaciers contribute second to sea level
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what is the preictio of 4.5rcp
very low baseline or hevay mitigation, v low cropland and pasture, mediu pollution, third laicers contriubte to sea level rise
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what is the rcp 2.6 likely to predict?
v low baseline and heavy mitigation, medium agricultural area, medium low pollution, and less ocntrubtuon of glaicer to sea level risewhat
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what is predicted to happen to the greenland ice sheet?
icnreasingly negative surface mass balance, dynamic retreat ongoing and up to 0.2 m sea level equilivent over the next decade
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what is predicted to happen to the antartica ice sheet?
increasingly positive surface mass balance, potential for large dynamically driven mass loss and up to 0.2m sea level equilivent over the next decade
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what is the uncertainity in models?
process repesentation, paramter uncertainity, input data uncertainity, lack of data
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what% of antartica is covered by ice
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what is solar radition called and how many units is it measured by?
constant, 4dp, look at number of sunspots of the reflection of sun and blackspots are the output
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what are the three types of oribatal variaitons?
precession (the season in whcih the earth is nearest/farthest the sun 20ka), tilt, tilt of the earth 40ka and eceentricity, how round is the orbit 100ka milatkovitch cycles
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what are some erosional landforms
micro(crescentic gouges and striations), meso rochee mountains and rag and tails, macro (u shaped valleys, fjords and hanging valleys)
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what are depositional landforms
eskers, kettle lakes, kames ( glacial-fluvial material elft behind) and terminal, lateral and medial moraines
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when ice was at its max level how many metres did sea level drop by
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what were the names of the former ice sheets
laurentide, british, euraian, patagonia, new celand, iceland, anatartica and greenland
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what is ploar amplification
most intense changes happen at the north and south poles
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what happens if you increase/ decrease albedo?
increase albedo, more reflecitity, lower temp, glaciation, if you decrase albedo then lower reflectivity, greater temp and deglacaition
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why does temp cool with height?
cold air holds less mositure so there is more accumulation and less melting, mass balance positive, ice sheet grows, whcih affects the movement of jet streamss
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what is the cause and effect ?
co2 is lower in glaicla environments, if glaciers melt due to warming there is more co2 released in the atmopshere, if you drop temp of the planet the c02 dissolves in the water
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what has the impact of former ice sheets modelled using GCM has seen?
laurentide become topographic barrier to atmopsheric circulation which is affected by jet streams and weather patterns
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where is polar amplification strongest
northern hemsiphere, less potential for albedo feedback in s hemisphere due to sea ice distrubution
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what is polar ampification
any change in net radition balance trends to produce a larger change in temp near the poles than the planetary average
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what do geochemsits and paelociamtists use to measure rates and ata of land surafces?
ultra-rare cosnmogenic nucleotides
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what is the albedo?
reflecitvity of a surface
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what is the order how quickly parts of the crysophere are made from lowest to highest?
snow, lake/river ice, snow ice, glaicers and ice caps, frozen ground, ice caps, ice sheet parigs, ice shelves and ice sheets
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what is glaical distrubition ocntrolled by
temo, precipitation, altitude and latitude
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what is an ice field galcier
interconnected valley system, where glaicers flow from one main glaicer, outlet glaicers have differnt shapes and forms, largest, netowrk
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what is a valley glacier
glaicer is just one unit and all flows ogether as one unit, shape is the same and flows onto coastal platform or marine terminating
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what are mountain glaciers
bigger than 0.01km2
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what is axel hieberg andcanaian arctic examples of
piedmont glaicers
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what is hubbard glaciers, alaska examples of?
surging glaicers
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what glaicers retreat and advance quickly and exmaples is james ross island in antartica
tide water glaicers
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what is uncostrainged bytopography?
ice sheets that are bigger than 50'000km^2 and ice caps that are less than 50'000km2, ice domes, ice devides, outlet glaicers, ice streams and ice shelf
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what are some ice cap examples
agassiz, severnyisland, vatnajokull, austfanna
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what are some ice sheet examples
antartica 14 times 10^6 and greenland 2 times 10^6
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what can ice sheets be and which ones are lciamte sensitive
terrestial (on land) and marine (under water) marine are more sensitive
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what are rivers of ice
constrained by topography, outlet glaciers, common in greenland, tide water
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what are ice streams
constrained by topogra[hy(slow moving ice), common in antartica, bed is more lubricated than the area underlying it so it travles fast
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what are ice shelves?
extensions of glaciers, that float beyond the groudning line, thickened ice whcih moves quickly
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what are icebergs
calve from ice shelves/floating tongues, ice is less dense than water so it floats, only tip sticks out
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what are calving events and how are they measured
measured using ice rafted debris which can track calving events and the material which travels/ erodied from glaicer/iceberg etc
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when does artic and antartica have its max and min sea ice extent
artic, max, in march, min in spetmber and antartica is vice versa
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what is mass balance
different between abltation and accumulation, postiive is when there is more accumulation in the accumulation zone and negative is more ablation than accumulation
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what is the ela
equilibrium line alitude differnet between these, it is lower when temp are lower and the glaciers exampnds with greater snow and is higher when temp are higher and these is deglaciation, less snowfall
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from major to minor what are the forms of accumualtion
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what are the major to minor forms of ablation
calving, melting, wind blown drift, avalanches, sublimation and evaporation
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what happens when you compact snow
get firn and then compact it more you get ice
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what is energy balance and abltation influenced by?
albedo, radiation reflection, absorbtion and scattering, heat transfer with air and latent heat, supradebris glaical cover, thin debris, more absorbtion and rereadtion, increased abltation, thick less ablation, decreased conduction, increased protect
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where can debris sit and what can prtectthe glacier from ablation
depression, glaical mice and supraglacial debris
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what is dry calving
very rare, ice breaking of in glaciers in steep mpuntain environments, when it comes acorssa change in topography
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what is wet calving
more common, as influenced by septh, temperature salinity, tidal variaiton, glaicer crevassing, presence of surface meltwater
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what is basal melting
melting caused by the 'warm' ocean casuing the end of the glaicer to melt, casuing grounding line to retreat
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what is the grounding line
when the ice begins to float
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what us grounded ice sub glacial a fucntion of
geothermal heat fluxes, ice velocity (generates friction as it moves and rubs against the ocean floor)
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where is there an increase in mass balance
higher altitudes, maritime has higher accumulation and ablation and continental has low accumulation and ablation, greater the mass balance differnce, the faster the flow
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what is a glaicer
accumulation of ice that flows under its own weight generally odownhill, ice is strong but yields under its own stress
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what are the three components of ice flow
internal deformation, subglacialdeformation and basal sliding
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what would ice flow look lie if there wasnt ablation or accumulation for a long time
thick treeacle spreading out
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how does velocity change
decreases with depth, basal belocy in this case is 0, velocity decreases at margins, velocity at margin is low, high lateral drag
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what controls ice temp
surface energy balance, geothermal heat flux, fricitonal heat due to friction being created when ice flows across surface through sliding and deformation, refreezing of meltwater at depth
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what controls temp at the surfcae, in the glaicer and under it
the air above it, the advection of ice and ice flow and then geothermal heat fluxes
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what is it called when ice metls at lower temp at higher pressure
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what are the different temperture regime of glaicers
cold, warm, polytherma(micture between the two)
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what are the factors controlling sliding
bed roughness(obstancles in its way), quantity and distrubtion of water at the bed, MOUNT OF DEBIS EMBEDDED IN THE BASE OF THE GLACIER
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what is sedimen deformation
ice is usually underlain by soft desiments, rsather than hard, this can deform allowing ice to flow fast but it depends on water content of sediment, high water, sedimet is less strong and less able to resist deofmration
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Other cards in this set

Card 2


What happened to the maritime glaicers in europe, norway?


maritime glaicers advances 1980-2000 and then retreated and is linked with strong positive north atlantic oscillations causing increased westerlies and accumulation

Card 3


What happened to the one in new zealand?


Preview of the front of card 3

Card 4


What happened in greenland?


Preview of the front of card 4

Card 5


What happened in antartica?


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