Ninth International Conference on Permafrost ... - IARC Research

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Continued Permafrost Warming in Northwest Alaska as Detected by the DOI/GTN-P Borehole ArrayGary D. ClowU.S. Geological Survey, Lakewood CO 80225, USAThe U.S. Department of the Interior contributes to theGlobal Terrestrial Network for Permafrost (GTN-P) with a21-element deep borehole array located in northwest Alaska.The majority of the holes are located on the Arctic CoastalPlain (ACP) with the remainder being in the northernfoothills of the Brooks Range (Fig. 1). All but two of theboreholes penetrate the base of permafrost which is situatedbetween 210 and 410 m in this region.The U.S. Geological Survey began monitoring temperaturesin the DOI/GTN-P boreholes in the late 1970s, soon after theholes were drilled. This was done by periodically reloggingthe wells with a portable temperature logging system (PTLS)developed especially for this purpose at USGS. While theoriginal PTLS was limited to an incremental or “stop-andgo”logging mode, improvements allowed the PTLS toacquire “continuous” temperature logs by the mid-1980s.Further refinements have reduced the standard uncertaintyof the ITS-90 temperature measurements obtained with thissystem to less than 3.3 milliKelvin. Early results whichfocused on interpretation of the curvature of the boreholetemperature profiles for past climatic changes were reportedby Lachenbruch and Marshall (1986) and Lachenbruch etal. (1988).Monitoring the thermal response of permafrost tocontemporary climate change has been the primary researchfocus of the DOI/GTN-P monitoring network for the lastdecade. Due to logistical constraints, our current protocolis to relog the entire borehole array every five years with afew key wells being relogged annually. Measurements in thewells show that near-surface temperature fluctuations in NWAlaska were generally small during the late 1970s and mostof the 1980s, except for a short cold period during 1983–84.Permafrost temperatures began warming dramatically in1989. By 2002–03, near-surface permafrost temperatureshad warmed 3 K on average across the array relative to1989. The coastal plain portion of the borehole array wasrelogged again during 2007 in support of the internationalThermal State of Permafrost (IPY/TSP) project. These newmeasurements show that shallow permafrost temperatureshave continued to warm on the ACP since 2002–03; themagnitude of the warming since 2002–03 ranges 0.0 to 1.0K (mean = 0.4 K), depending on local site conditions. Thetotal average (shallow) permafrost warming in this regionsince 1989 is now ~ 3.5 K (Fig. 1).Data from the co-located DOI/GTN-P active layer/meteorological network show that the 2002–03 boreholemeasurements coincided with a peak in mean annual airtemperatures in NW Alaska. Mean annual air temperaturescooled substantially during 2004, but have been rising sinceand are now warmer than those experienced during 2002–03. Permafrost temperatures have not tracked the post-2004air temperature warming due to the effects of changing snowcover.Figure 1. Location of the DOI/GTN-P boreholes in northwestAlaska. Also shown is the magnitude (degrees Kelvin) of shallowpermafrost warming at various well sites on the coastal plainbetween 1989 and 2007.Figure 2. Sample permafrost temperatures measured in one of thecoastal plain DOI/GTN-P boreholes (East Teshekpuk) since 1977.Extrapolated mean annual surface temperatures have increasedabout 3.6 K at this site since the late 1970s, close to the averagefor the entire array.47
Ni n t h In t e r n at i o n a l Co n f e r e n c e o n Pe r m a f r o s tFigure 3. Time series of extrapolated mean annual surfacetemperatures derived from the borehole temperature measurementsat the East Teshekpuk well site.ReferencesLachenbruch, A.H. & Marshall, B.V. 1986. Changingclimate: geothermal evidence from permafrost inAlaska. Science 234: 689-696.Lachenbruch, A.H., Cladouhos, T.T. & Saltus, R.W. 1988.Permafrost temperature and the changing climate.Proceedings of the Fifth <strong>International</strong> <strong>Conference</strong> onPermafrost, 1988: 9-17.48
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ContentsPreface ...................
Page 8 and 9:
Mapping and Modeling the Distributi
Page 10 and 11:
Satellite Observations of Frozen Gr
Page 13 and 14:
xiiIce Wedge Thermal Regime in Nort
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xivPermafrost Response to Dynamics
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Page 19 and 20: NICOP SponsorsUniversitiesUniversit
Page 22 and 23: Deep Permafrost Studies at the Lupi
Page 24 and 25: Effect of Fire on Pond Dynamics in
Page 26 and 27: Cryological Status of Russian Soils
Page 28 and 29: Acoustical Surveys of Methane Plume
Page 30 and 31: Permafrost Delineation Near Fairban
Page 32 and 33: Preparatory Work for a Permanent Ge
Page 34 and 35: A Provisional Soil Map of the Trans
Page 36 and 37: Martian Permafrost Depths from Orbi
Page 38 and 39: Time Series Analyses of Active Micr
Page 40 and 41: Impact of Permafrost Degradation on
Page 42 and 43: DC Resistivity Soundings Across a P
Page 44 and 45: Modeling Thermal and Moisture Regim
Page 46 and 47: A Provisional Permafrost Map of the
Page 48 and 49: Alpine Permafrost Distribution at M
Page 50 and 51: Cryogenic Formations of the Caucasu
Page 52 and 53: Modeling Potential Climatic Change
Page 54 and 55: A Hypothesis: A Condition of Growth
Page 56 and 57: Modeled Continual Surface Water Sto
Page 58 and 59: Freeze/Thaw Properties of Tundra So
Page 60 and 61: Discontinuous Permafrost Distributi
Page 62 and 63: Thermal Regime Within an Arctic Was
Page 64 and 65: Seasonal and Interannual Variabilit
Page 66 and 67: Twelve-Year Thaw Progression Data f
Page 70 and 71: Landsliding Following Forest Fire o
Page 72 and 73: A Permafrost Model Incorporating Dy
Page 74 and 75: Seasonal Sources of Soil Respiratio
Page 76 and 77: Greenland Permafrost Temperature Si
Page 78 and 79: The Importance of Snow Cover Evolut
Page 80 and 81: The Account of Long-Term Air Temper
Page 82 and 83: The Combined Isotopic Analysis of L
Page 84 and 85: Adaptating and Managing Nunavik’s
Page 86 and 87: Human Experience of Cryospheric Cha
Page 88 and 89: HiRISE Observations of Fractured Mo
Page 90 and 91: A Soil Freeze-Thaw Model Through th
Page 92 and 93: Mapping and Modeling the Distributi
Page 94 and 95: First Results of Ground Surface Tem
Page 96 and 97: Historical Changes in the Seasonall
Page 98 and 99: Rock Glaciers in the Kåfjord Area,
Page 100 and 101: Snowpack Evolution on Permafrost, N
Page 102 and 103: Climate Change in Permafrost Region
Page 104 and 105: Maximizing Construction Season in a
Page 106 and 107: Pleistocene Sand-Wedge, Composite-W
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