Imnavait Creek WET

General Information

Created: 2014-02-03 13:18:58
Modified: 2015-11-10 10:02:53

Active: No
Country:United States
CALM-Code:U11 B
Responsible Countries: United States,
Timezone:UTC/GMT -09:00 hours
Vegetation Type:Tundra
Responsible Person:Nikolay Shiklomanov
Offset:5 m


U11B 1-ha grid located within the lower part of U11A 1 km grid. Site description: Gentle (1 degree) north facing basin deposit with strangmoor, wetland hummocks, palsas; wet acidic tundra. Vegetation communities: (1) Raised microsites in basin including hummocks and palsas: Wet Carex rotundata, C. rariflora, Betula nana, Salix fuscescens, Sphagnum lenense graminoid, dwarf-shrub tundra. (2) Footslope of west-facing hill: Moist Betula nana, Eriophorum vaginatum, Sphagnum spp. dwarf-shrub, tussock-graminoid tundra. (3) Lower microsites in basin including interhummock areas with standing water: Wet Eriophorum scheuchzeri, Carex rotundata, Sphagnum orientale, Drepanocladus revolvens graminoid tundra. (4) Marginal area of the basin with few shrubs: Wet Carex rotundata, Salix fuscescens, Sphagnum lenense graminoid, moss tundra. (5) Beaded pond of Imnavait Creek: Aquatic Sparganium hyperboreum, Hippuris vulgaris forb marsh. Cover of top 5 species: Sphagnum lenense (13%), Carex rotundata (8%), Sphagnum warnstorfii (7%), Betula nana (6%), Sphagnum orientale (6%).

Mean vegetation height: 2.2 +/- 3.2 cm

Mean live moss layer thickness: 2.0 +/- 1.0 cm

Organic layer thickness: 34 + 1.7 cm.

 (Walker and Bockheim, 1995)



Beginning in 1995, the active layer has been probed at least annually at the site. The procedure involves pushing a metal rod, calibrated in cm, to the point of refusal, interpreted in most cases to be the frost table. Thaw depth measurements at each site were obtained by probing at 5 m intervals along the plot’s two perpendicular and one diagonal transect, resulting in 71 points per plot per probing date.

In 1995 the site was instrumented with several OnsetTM portable data loggers connected to probe-type thermistors. Each logger/thermistor system has an effective temperature range of -50oC to +33oC and resolution of approximately 0.32oC. At each site, one thermistor was placed in a radiation shield approximately 2 m above the ground surface, and nine loggers were placed at the interface between mineral soil and organic material in various microtopographic positions within the site. Temperature measurements were collected at, 1 hr, and 2 hr intervals depending on season, and year. Details on methodology are provided in Klene et. al 2001.


Additional climate snow and hydrologic data are also available at

Slope:5 °
Permafrost Zone:Continuous
Vegetation:Wet acidic tundra
Landform:Glaciated foothills
Lithology:Histic Pergelic Cryaquepts (54%), P. Cryofibrists (35%), P. Cryaquepts (10%). Organic layer thickness: 34 + 1.7 cm. Soil texture - silt
Description:General description of soil moisture : Wet to saturated
Access Timeseries
Bibliographic References
Nelson, F.E., Shiklomanov, N.I., and G.R. Mueller. Variability of active-layer thickness at multiple spatial scales, north-central Alaska, USA. 1999 Arctic, Antarctic, and Alpine Research, 31(2): 179-186.
Bockheim, J.G., Walker, D.A., Everett, L.R., Nelson, F.E. and N.I. Shiklomanov. 1998 . Soils and cryoturbation in moist nonacidic and acidic tundra in the Kuparuk River basin, Arctic Alaska, USA. Arctic and Alpine Research, 30(2): 166-174.
Walker, D. A., and J. G. Bockheim, Site selection for the portable flux towers, ARCSS/LAII/Flux Study, 1316 June 1995, Summary of field activities, Land-Atmos.-Ice Interact. Sci. Manage. Off., Geophys. Inst.,Univ. of Alaska-Fairbanks, 1995.
Shiklomanov, N.I. and F.E. Nelson. 2003 Climatic variability in the Kuparuk region, north-central Alaska: optimizating spatial and temporal interpolation in a sparse observation network. Arctic, 56: 136-146.
Shiklomanov, N.I. and F.E. Nelson. 2003 Statistical representation of landscape-specific active-layer variability. In Phillips, M., Springman, S. M., and Arenson, L. U. (eds.), Proceedings of the Eighth International Conference on Permafrost, vol. 2. Lisse: A.A. Balkema, 1039-1044.
Walker D.A., Jia G.J., Epstein H.E., Raynolds M.K., Chapin III F.S., Copass C., Hinzman L.D., Kane D., Knudson J.A., Maier H., Michaelson G.J., Nelson F.E., Ping C.L., Shiklomanov N.I., Romanovsky V.E., Shur Y. 2003 Vegetation-soil-thaw-depth relationships along a Low Arctic bioclimatic gradient, Alaska: Synthesis of information from the Atlas studies. Permafrost and Periglacial Processes, 14: 103-123.
Shiklomanov N. I. and F. E. Nelson, F. E., 2002. Active-layer mapping at regional scales: a 13-year spatial time series for the Kuparuk region, north-central Alaska. Permafrost and Periglacial Processes, 13: 219-230.
Klene A.E., Nelson F.E., Shiklomanov N.I., and K.M. Hinkel. 2001 The n-factor in natural landscapes: Variability of air and soil-surface temperatures, Kuparuk River basin, Alaska. Arctic, Antarctic and Alpine Research, 33(2): 140-148.
Nelson, F.E., Hinkel, K.M., Shiklomanov, N.I., Mueller, G.R., Miller, L.L., and D.A. Walker. Active-layer thickness in north central Alaska: systematic sampling, scale, and spatial autocorrelation. 1998 Journal of Geophysical Research-Atmospheres, 103(D22): 28963-28973.
Nelson, F.E., Outcalt, S.I., Brown, J., Shiklomanov, N.I., and K.M. Hinkel. Spatial and temporal attributes of the active-layer thickness record, Barrow, Alaska, USA, 1998 Proceedings of the Seventh International Conference on Permafrost. Centre de etudes nordiques de l'Universite Laval, Laval, Quebec, Canada, Yellowknife, NWT, Canada, pp. 797-802
Walker, D.A., Auerbach, N.A., Bockheim, J.G., Chapin, F.S., Eugster, W., King, J.Y., McFadden, J.P., Michaelson, G.J., Nelson, F.E., Oechel, W.C., Ping, C.L., Reeburg, W.S., Regli, S., Shiklomanov, N.I., and G.L. Vourlitis.1998 Energy and trace-gas fluxes across a soil pH boundary in the arctic. Nature, 394(6692): 469-472.
Nelson F.E., Shiklomanov, N.I., Mueller G.R., Hinkel K.M., Walker D.A., and J.G. Bockheim.1997 Estimating active-layer thickness over a large region: Kuparuk River basin, Alaska, USA. Arctic and Alpine Research, 29(4): 167-378.
Klene A.E., Nelson F.E., and N.I. Shiklomanov. 2001 The n-factor as a tool in geocryological mapping: seasonal thaw in the Kuparuk River Basin, Alaska. Physical Geography, 22(6): 449-466.
Shiklomanov, N.I. and F.E. Nelson. Analytic representation of the active layer thickness field, Kuparuk River basin, Alaska. 1999 Ecological Modelling, 123: 105-125.

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U11b Imnavait Creek WETU11b Imnavait Creek WET2

Longitude:-149.3145 °
Latitude:68.611 °
Elevation:895.52929688 m
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