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Evidenceofmeltwaterreten1onwithinthe

GreenlandIcesheet

saK.Rennermalm,RutgersUniversity(SUNJ)LaurenceC.Smith,UniversityofCaliforniaLosAngeles

VenaC.Chu,UniversityofCaliforniaLosAngelesJasonE.Box,OhioStateUniversity

RichardR.Forster,UniversityofUtahMichielvandenBroeke,UtrechtUniversity

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Runoff~50%masslosses

SpaPallydistributedsurfacemassbalancemodels Eemaetal2009,MernildandListon2012,Feweis2007,Hannaet

al2005,vandenBroekeetal2009

MassbalanceesPmatesfromGRACE Woutersetal2008,vandenBroekeetal,2009,Siemesetal2012,

HarigandSimons2012

Increasedrunoff RelevanceforgeochemistryandmicrobialacPvity

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April24,2009photoThe image cannot be displayed. Your computer may not have enough memory to open the image, or the image may have been corrupted. Restart your computer, and then open the file again. If the red x still appears, you may have to delete the image and then insert it again.

Photo taken by K. Steffen

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SciencequesPon

Howmuchicesheetsurfacerunoffescapetotheocean?

Whenismeltwaterreleased?

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Howmuchreachestheocean?

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bedrock

ice

firnsnow

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firnaquifer

icelenses

bedrock

ice

firnsnow

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crevasses

supraglacialstreamnetwork

moulins

supraglacial

lakes

firnaquifer

icelenses

bedrock

ice

firnsnow

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crevasses

englacial

drainage

system

subglacialstorage

incavities

subglacial

channels

supraglacialstreamnetwork

moulins

supraglacial

lakes

firnaquifer

icelenses

bedrock

ice

firnsnow

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crevasses

englacial

drainage

system

subglacialstorage

incavities

subglacial

channels

supraglacialstreamnetwork

moulins

supraglacial

lakes

firnaquifer

icelenses

bedrock

ice

firnsnow

Evaporation

Sublimation

Precipitation

Melt

Proglacial

storage

Runoff

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Icesheetcontrolledriver

roglacialriver

dischargemeasurements

Icesheetrunoffvolume

-River

dischargeMeltwaterstorage

Icesheetrunoffmodeling

ElevaPondependentSMB vandenBroekeetal.2008

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Studyarea

DrainageareaesPmaPonwASTERGDEM 64km2

Ice sheet melt

River discharge

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CumulaPveicesheetsurfacerunoff

Rennermalm et al. (2012) The Cryosphere Discussions

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CumulaPveicesheetsurfacerunoff

Rennermalm et al. (2012) The Cryosphere Discussions

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CumulaPveicesheetsurfacerunoff

Rennermalm et al. (2012) The Cryosphere Discussions

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Expectedriverdischarge

Rennermalm et al. (2012) The Cryosphere Discussions

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ActualsituaPon

Rennermalm et al. (2012) The Cryosphere Discussions

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ActualsituaPon

Rennermalm et al. (2012) The Cryosphere Discussions

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ActualsituaPon

Rennermalm et al. (2012) The Cryosphere Discussions

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10-50%retenPon

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Lessthan1%oficevolumeretained

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Rennermalm et al. (2012) The Cryosphere Discussions

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Dampenedriverresponse

Rennermalm et al. (2012) The Cryosphere Discussions

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Coldseasonmeltwaterrelease

Rennermalm et al. (2012) The Cryosphere Discussions

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Morethan10%dischargeislostinthecoldseason

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OtherevidenceforicesheetmeltwaterretenPonanddelayed

release

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Colganetal.(2011)J.Glaciology1DverPcallyintegratedflowlinemodelYearroundsubglacialconduitstorageMeanglacierresidencePmeforwater2.5years

CataniaandNewman(2010)GRLGroundpenetraPngradarersistentenglacialhydrologicfeaturesthroughwinter

Harperetal.(2012)NatureFirnstorage Foresteretal.(2012)AGU

erennialfirnaquifers

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Conclusions

MeltwaterretenPonbeyondayear ColdseasonreleaseofenglacialmeltwaterNosupraglacialorproglaciallakes

InsignificantprecipitaPon Limitedsnow/firnstorage Englacialand/orsubglacialstorage

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Acknowledgements

ThisworkwassupportedbytheNASACryosphererogram(grantNNX11AQ38G),managedbyDr.Thomas.Wagner

Tofindoutmore Rennermalmetal.(2012)TheCryosphereDiscussions SessiononGlacierHydrology,Thursday10:20-12:20inthisroom

ostersinC43CsessionThursday1:406pm: SamiahMoustafa:C43C-0623 AsaRennermalm:C43C-0616