Ninth International Conference on Permafrost ... - IARC Research

More documents

Recommendations

Info

Permafrost Dynamics and Landscape Changes in a Subarctic Peat Plateau,Northern SwedenA.B.K. SannelDepartment of Physical Geography and Quaternary Geology, Stockholm University, SwedenP. KuhryDepartment of Physical Geography and Quaternary Geology, Stockholm University, SwedenIntroductionPerennially frozen peatlands in subarctic regions aresensitive to a warming climate, since permafrost temperaturesare close to the 0°C mean annual isotherm. Few monitoringstudies have been performed of permafrost dynamics insubarctic peatlands because of their often remote location,the expensive logistics, and the harsh field conditions.Rapid and extensive permafrost thawing in bogs andmixed mires underlain by permafrost in northern Sweden hasbeen recorded by Christensen et al. (2004). Zuidhoff (2002)conclude that in palsas block erosion, thermokarst and winderosion are the most important degradational processesinvolved in the decay. Sollid & Sørbel (1974) found thatwhere frozen palsa plateaus are in direct contact with water,the permafrost core is undermined, causing cracks in thepeat. The peat then slips sideways, creating a steep erosionedge. This edge gradually works its way in towards thecentral part of the palsa.In a modeling study from Russia, Mazhitova et al. (2004)suggest a 20–30 cm deepening of the active layer in peatplateaus until 2080 as a result of future global warming. Itis not only the air temperature that affects the thaw depth;precipitation, snow depth, the ice content in the ground, andother hydrogeological conditions are also important factorsfor the active layer distribution (Oberman & Mazhitova2001). Long-term ecosystem monitoring is important forpredicting the behaviour of subarctic peatlands under theexpected future warmer and wetter climate conditions.Aim, Methods, and Study AreaThe main objective of this project is to study local climateand ground dynamics in a subarctic peat plateau/thermokarstlake complex in order to get a better understanding of howthese permafrost peatlands will respond to climate change.Which factors and mechanisms cause the collapse of peatplateaus into thermokarst lakes? Why does the erosion occuronly in certain parts of the peat plateau and along certainparts of the thermokarst lake shoreline? How sensitive arethese ecosystems to global warming? At the peat plateau/thermokarst lake complex in Tavvavuoma (68°28′N,20°54′E), northern Sweden, permafrost temperature andlandscape dynamics are studied through monitoring ofground temperatures, meteorological data, and snow depth(since 2005), and a time series analysis of aerial photographsand satellite images (from 1963 to 2003). On the peat plateau,snow depth and ground temperatures down to 2 m depth arerecorded at 9 different microsites; on the peat plateau, at theFigure 1. Map showing the location of thermistor cables and snowdepth stakes at the monitoring site in Tavvavuoma.eroding edge of the peat plateau, in the thermokarst lake, andin a nearby non-permafrost fen (Fig. 1, 2, 3). A 20 m deepborehole for ground temperature measurements is planned.Air temperature, precipitation, and wind data are recordedon top of the plateau. Snow depth is monitored by using astationary digital camera that records one image per day.Preliminary Results and DiscussionA comparison of panchromatic aerial photographs with arecent IKONOS image shows that, on a landscape level,major thermokarst drainage has occurred between 1963 and2003. Along the present thermokarst lake shorelines, fieldobservations show that erosion is active. Ground subsidenceof up to 11 cm in 2 years has been observed along theshoreline, whereas the central parts of the monitored peatplateau surface appear to remain stable. The monitoringdata are indicating that the permafrost in the peat plateau isthawing out, probably due to recent warming. On the central,dry peat plateau sites, the ground temperatures below 1 mdepth are just below 0°C, implying that the peat plateauwill be very sensitive to any further increase in temperature.Winter observations indicate very thin snow cover at thetop of the peat plateau compared to the edges and in thethermokarst depressions, showing the importance of snowdistribution for the permafrost (Fig. 4).265
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 2. The peat plateau/thermokarst lake complex withmonitoring equipment.Figure 4. Snow distribution at the edge of the thermokarst lake andon top of the peat plateau, December 2007.Figure 3. Ongoing monitoring activities at the peat plateau/thermokarst lake complex in Tavvavuoma. Thermistor cables T1and T5–T7 have thermistors at 2 cm, 10 cm, 25 cm, 50 cm, and 100cm depth. Thermistor cables T2–T4 and T9 also have thermistorsat 150 cm and 200 cm depth. T8 has thermistors located 70 cm, 110cm, 150 cm, 190 cm, and 230 cm below the lake sediment surface(for location of the thermistor cables, see Fig. 1a).ReferencesChristensen, T.R., Johansson, T., Åkerman, H.J.,Mastepanov, M., Malmer, N., Friborg, T., Crill,P. & Svensson, B.H. 2004. Thawing sub-arcticpermafrost: Effects on vegetation and methaneemissions. Geophysical Research Letters 31: L04501,doi:10.1029/2003GLO18680.Mazhitova, G., Karstkarel, N., Oberman, N., Romanovsky,V. & Kuhry, P. 2004. Permafrost and infrastructure inthe Usa Basin (northeast European Russia): Possibleimpacts of global warming. Ambio 33(6): 289-294.Oberman, N.G. & Mazhitova, G.G. 2001. Permafrostdynamics in the north-east of European Russia at theend of the 20 th century. Norsk Geografisk Tidsskrift55: 241-244.Sollid, J.L. & Sørbel, L. 1974. Palsa bogs at Haugtjørnin,Dovrefjell, South Norway. Norsk Geografisk Tidsskrift28: 53-60.Zuidhoff, F.S. 2002. Recent decay of a single palsa in relationto weather conditions between 1996 and 2000 inLaivadalen, northern Sweden. Geografiska Annaler84A(2): 103-111.Warmer temperatures as well as increased precipitation inthe winter can cause thawing of the permafrost, resulting incollapse of the peat plateau and increased methane emissionsfrom thermokarst lakes. However, thawing of the permafrostcan also result in drainage of thermokarst lakes and renewedpeat accumulation.AcknowledgmentsFinancial support has been achieved by the GöranGustafsson Foundation, Foundation Lars Hiertas Minne,Helge Ax:son Johnson Foundation and Swedish Society forAnthropology and Geography. Thanks also to Prof. PeterJansson at Stockholm University!266
Page 1:
NICOP 2008 Ninth <
Page 6 and 7:
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
Page 15 and 16:
xivPermafrost Response to Dynamics
Page 17 and 18:
xvi
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 68 and 69:
Continued Permafrost Warming in Nor
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
Page 109 and 110:
Ni n t h In t e r n at i o n a l Co
Page 111 and 112:
Page 113 and 114:
Page 115 and 116:
Page 117 and 118:
Page 119 and 120:
Page 121 and 122:
Page 123 and 124:
Page 125 and 126:
Page 127 and 128:
Page 129 and 130:
Page 131 and 132:
Page 133 and 134:
Page 135 and 136:
Page 137 and 138:
Page 139 and 140:
Page 141 and 142:
Page 143 and 144:
Page 145 and 146:
Page 147 and 148:
Page 149 and 150:
Page 151 and 152:
Page 153 and 154:
Page 155 and 156:
Page 157 and 158:
Page 159 and 160:
Ni N t h iN t e r N at i o N a l Co
Page 161 and 162:
Page 163 and 164:
Page 165 and 166:
Page 167 and 168:
Page 169 and 170:
Page 171 and 172:
Page 173 and 174:
Page 175 and 176:
Page 177 and 178:
Page 179 and 180:
Page 181 and 182:
Page 183 and 184:
Page 185 and 186:
Page 187 and 188:
Page 189 and 190:
Page 191 and 192:
Page 193 and 194:
Page 195 and 196:
Page 197 and 198:
Page 199 and 200:
Page 201 and 202:
Page 203 and 204:
Page 205 and 206:
Page 207 and 208:
Page 209 and 210:
Page 211 and 212:
Page 213 and 214:
Page 215 and 216:
Page 217 and 218:
Ni N t h iN t e r N at i o N a l Co
Page 219 and 220:
Page 221 and 222:
Page 223 and 224:
Page 225 and 226:
Page 227 and 228:
Page 229 and 230:
Page 231 and 232:
Page 233 and 234:
Page 235 and 236: Ni n t h In t e r n at i o n a l Co
Page 253: Ni n t h In t e r n at i o n a l Co
Page 285: Ni n t h In t e r n at i o n a l Co
Page 337 and 338:
Page 339 and 340:
Page 341 and 342:
Page 343 and 344:
Page 345 and 346:
Page 347 and 348:
Page 349 and 350:
Page 351 and 352:
Page 353 and 354:
Page 355 and 356:
Page 357 and 358:
Page 359 and 360:
Page 361 and 362:
Page 363 and 364:
Page 365 and 366:
Page 367 and 368:
Page 369 and 370:
Page 371 and 372:
Page 373 and 374:
Page 375 and 376:
Page 377 and 378:
Page 379 and 380:
Page 381 and 382:
Page 383 and 384:
Page 385 and 386:
Page 387 and 388:
Page 389 and 390:
Page 391 and 392:
370Huang, B. 339Hugelius, G. 105, 1
Page 393:
372
show all

Ninth International Conference on Permafrost ... - IARC Research

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?