Arp, Christopher D.

Grosse, Guido

Jones, Benjamin M.

Nitze, Ingmar

Ulrich, Mathias

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Ingmar NitzePhD CandidateAlfred-Wegener-InstitutTelegrafenberg A4314473 Potsdam, Germanyingmar.nitze@awi.dePhone: +49-331-288-2126www.awi.deIngmar Nitze1,2, Guido Grosse1,3, Benjamin Jones4, Christopher Arp5, Mathias Ulrich61 Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Potsdam, Germany2 Institute of Geography, Geoinformatics, University of Potsdam, Germany3 Institute of Earth and Environmental Science, University of Potsdam, Germany4 United States Geological Service, Anchorage, USA5 Water and Environmental Research Center, University of Alaska Fairbanks, Fairbanks, USA6 Institute of Geography, University of Leipzig, Leipzig, GermanyObserved and projected climate change in the Arctic increases the vulnerability of terrestrial ecosystems to disturbances. For example, significant increases in air temperatures especially in high latitudes (Polar amplification) will impact the sta-bility of permafrost landscapes that cover 24% of the northern hemisphere and dominate large parts of the Arctic. So far, only small areas have been monitored regarding their landscape dynamics related to permafrost in an appropriate spati-al scale. This study seeks to overcome this massive knowledge gap with an inte-grated geo-informatics approach based on remote sensing time-series.ChallengesRapid landscape dynamicsRemote locationsLarge spatial extentCloud and snow and ice coverData processing and handlingGoalsMonitoring of thermokarst lake dynamicsUpscaling capabilitiesProduct easy to use and unterstand by stakeholdersImproved unterstanding of processesCurrent Knowledge BaseOnly knowledge of local dynamicsGlobal Surface Water problematic in high latitudesLarge diversity of data and methodsLittle knowledge about the Big PictureUsage of the full Landsat archive (TM, ETM+, OLI)  - Peak summer season (Jul, Aug), Cloud Cover < 70 %  - Years 1999 to 2014  - 1000‘s of scenes around the ArcticData pre-processing (Subset, Reproject, FMask, Stack)More Info: Nitze & Grosse (2016)Methods - Lake AnalysisIntroductionReferences: Brown, J., Ferrians, Jr. O. J., Heginbottom, J. A., and Melnikov, E. S.: Circum‐Arctic map of permafrost andground‐ice conditions, 1:10 000 000, Map CP‐45, United States Geological Survey, InternationalPermafrost Association, 1997.Nitze, I., & Grosse, G. (2016). Detection of landscape dynamics in the Arctic Lena Delta with temporally dense Landsat time-se-ries stacks. Remote Sensing of Environment, 181, 27-41.Machine-learning classification of processesObject based data analysisStatistical analysisMethods - Data Processing Methods - Lake Change AnalysisFig 1: Drained lake margin on the Alaska North Slope. Photo: I.NitzeFig 2: Eroding thermokarst lake shore on the Alaska North Slope. Photo: I.NitzeLake change analysis (> 1ha)Several sites across Arctic15yr Observation PeriodAutomated Processing Satellite Images Process ClassicationTrend DataRemote Sensing Data AnalysisSubpixel Analysis Lake AnalysisFig 4: Schematic data processing pipeline from raw satellite Image to object extracti-on and lake change calculation.Fig 3: Permafrost region with overview of study sites: Central Yakutia, Kolyma Region, Seward Peninsula, Kobuk-Selawik Region, Alaska North SlopeHighly scalable automated lake analysisLake area budget is a highly regional signalLake expansion (thermokarst) dominating processDrainage events important for regional budgetAllows enhanced assessment of underlying hydrological dynamicsConclusionsThis research was supported by ERC Starting Grant #338335, the Initiative and Networking Fund of the Helmholtz Association (#ERC-0013) and the ESA GlobPermafrost Project. Travel support was provided by POLMAR.Thermokarst lake drainage high frequency of low values occasional full drainage eventsPrimary PeakSecondary PeakGrowth RangeLake area decrease rate per lake over 15 yrsLake area increase rate per lake over 15 yrsFig 7: Statistical distribution of lake specific lake area increase and decrease rates.Lake growth dominates 95 % of all lakes are growing high frequency of low growth few partial drainage eventsRegional differences strong dynamics along coastLake growth dominates 82 % of all lakes are growing frequent full drainage eventsRegional differences strong general dynamics ( + and - )  flooding in river deltaSeward PeninsulaKobuk/Selawik RegionAlaska North SlopeCentral YakutiaKolyma Region- 1.9+ 4.6+ 2.9+ 76.4+ 2.3Fig 8: Regional lake area change budget.Regional lake area budgets predominantly lake area growth typical range up to + 5 % extreme change in Central Yakutia slight decrease on Seward Pen.Thermokarst lake growth typical range up to 40 %  lake size dependent Fig 6: a) Map of lake specific surface water area chan-ges in the Kobuk-Selawik Delta Region. b) Statistical Lake area change distribution in the Kobuk Delta.Fig 5: a) Map of lake specific surface water area chan-ges on the Alaska North Slope. b) Statistical Lake area change distribution on the Alaska North Slope.increasedecreaseincreasedecreaseAlaska North Slope Kobuk-Selawika)b)a)b)Results - Regional Statistics Results - Regional ComparisonHeadSubheadContentBREMERHAVENAm Handelshafen 1227570 Bremerhaven Telefon 0471 4831-0www.awi.dePartner-LogoPartner-LogoReferencesLorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invid-unt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmod tempor invidunt ut labore et dolore magna aliquyam erat, sed diam volup-tua. At vero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel illum dolore eu feugiat nulla facilisis at vero eros et accumsan et iusto odio dignissim qui blandit praesent l minim veniam, quis nostrud ea nobis eleifend option congue nihil imperdiet doming id quod mazim placerat facer possim assum. Lorem ipsum exerci tation ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo conse-quat. Duis autem vel eum iriure dolor in hendrerit in vulputate velit esse molestie consequat, vel Ingmar Nitze, Guido GrosseThermokarst lake dynamics across the Arctic based on Landsat time-series

Thermokarst lake dynamics across the Arctic based on Landsat time-series

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