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Jorgenson, M. Torre; Racine, Charles H.; Walters, James C.; Osterkamp, T. E.

doi:10.1023/a:1005667424292

Cited by 627 publications

(156 citation statements)

References 42 publications

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“…2010, and its lateral coverage dropped below 5.0 % in three of the four study areas ( Table 2). The residual permafrost plateaus documented in this study share similar attributes to features elsewhere in boreal peatlands for which permafrost degradation has been inferred due to the ease of remotely detecting the conversion from forested permafrost plateau to non-permafrost herbaceous wetland or waterbody (Jorgenson et al, 2001(Jorgenson et al, , 2008a. Thie (1974) inferred a permafrost plateau loss rate of 0.47 % yr −1 between 1800 and 1960 for a 130 000 ha area of southern Manitoba.…”

Section: Extent and Change In Residual Permafrost Plateaus Since The supporting

confidence: 73%

“…3). These traits were characteristic of the permafrost features described by Hopkins et al (1955) on the Kenai Peninsula and similar to permafrost plateaus across colder boreal regions (Zoltai, 1972;Thie, 1974;Jorgenson et al, 2001;Camill, 2005;Sannel et al, 2015). To answer whether the frozen deposits encountered at the black spruce plateaus were indeed permafrost, we collected continuous ground temperature measurements for 3 years, measured late-summer thaw depths, mechanically drilled and cored for the base of the frozen ground, imaged the subsurface with ground-penetrating radar (GPR), and analyzed a time series of high-resolution remotely sensed imagery.…”

Section: Methodssupporting

confidence: 63%

“…Mapping forested-plateau features and their change over time is a common method for detection of permafrost thaw in boreal wetlands. The land cover change associated with conversion of a forested permafrost plateau to a lake or herbaceous wetland (i.e., bog or fen) is readily detectable in high-resolution remotely sensed imagery (Thie, 1974;Camill and Clark, 1998;Osterkamp et al, 2000;Jorgenson et al, 2001Jorgenson et al, , 2008aPayette et al, 2004;Quinton et al, 2011;Lara et al, 2016).…”

Section: Remotely Sensed Imagery and Change Detectionmentioning

confidence: 99%

“…Permafrost warming, degradation, and thaw subsidence can have significant implications for ecosystems, infrastructure, and climate at local, regional, and global scales (Jorgenson et al, 2001;Nelson et al, 2001;Schuur et al, 2008). In general, permafrost in Alaska has warmed between 0.3 and 6.0 • C since ground temperature measurements began between the 1950 and 1980s (Lachenbruch and Marshall, 1986;Romanovsky and Osterkamp, 1995;Osterkamp, 2007).…”

mentioning

confidence: 99%

“…Such land surface changes can impact vegetation, hydrology, aquatic ecosystems, and soil-carbon dynamics (Grosse et al, 2011;Jorgenson et al, 2013;Kokelj et al, 2015;O'Donnell et al, 2011;Schuur et al, 2008;Vonk et al, 2015). For example, in boreal peatlands, thaw of ice-rich permafrost often converts forested permafrost plateaus into lake and wetland bog and fen complexes (Camill, 1999;Jorgenson et al, 2001;Payette et al, 2004;Kuhry, 2008, 2011;Quinton et al, 2011;Jorgenson et al, 2012;Kanevskiy et al, 2014;Swindles et al, 2015;Lara et al, 2016). Furthermore, the transition from permafrost peatlands to thawed or only seasonally frozen peatlands can have a positive or a negative feedback on regional and global carbon cycles depending on permafrost conditions and differential effects of thaw on net primary productivity and heterotrophic respiration (Turetsky et al, 2007;Swindles et al, 2015), as well as on the degree of loss of the former deep permafrost carbon pool .…”

mentioning

confidence: 99%

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Presence of rapidly degrading permafrost plateaus in south-central Alaska

et al. 2016

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Abstract. Permafrost presence is determined by a complex interaction of climatic, topographic, and ecological conditions operating over long time scales. In particular, vegetation and organic layer characteristics may act to protect permafrost in regions with a mean annual air temperature (MAAT) above 0 • C. In this study, we document the presence of residual permafrost plateaus in the western Kenai Peninsula lowlands of south-central Alaska, a region with a MAAT of 1.5 ± 1 • C . Continuous ground temperature measurements between 16 September 2012 and 15 September 2015, using calibrated thermistor strings, documented the presence of warm permafrost (−0.04 to −0.08 • C). Field measurements (probing) on several plateau features during the fall of 2015 showed that the depth to the permafrost table averaged 1.48 m but at some locations was as shallow as 0.53 m. Late winter surveys (augering, coring, and GPR) in 2016 showed that the average seasonally frozen ground thickness was 0.45 m, overlying a talik above the permafrost table. Measured permafrost thickness ranged from 0.33 to > 6.90 m. Manual interpretation of historic aerial photography acquired in 1950 indicates that residual permafrost plateaus covered 920 ha as mapped across portions of four wetland complexes encompassing 4810 ha. However, between 1950 and ca. 2010, permafrost plateau extent decreased by 60.0 %, with lateral feature degradation accounting for 85.0 % of the reduction in area. Permafrost loss on the Kenai Peninsula is likely associated with a warming climate, wildfires that remove the protective forest and organic layer cover, groundwater flow at depth, and lateral heat transfer from wetland surface waters in the summer. Better understanding the resilience and vulnerability of ecosystem-protected permafrost is critical for mapping and predicting future permafrost extent and degradation across all permafrost regions that are currently warming. Further work should focus on reconstructing permafrost history in south-central Alaska as well as additional contemporary observations of these ecosystem-protected permafrost sites south of the regions with relatively stable permafrost.

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Section: Extent and Change In Residual Permafrost Plateaus Since The supporting

confidence: 73%

Section: Methodssupporting

confidence: 63%

Section: Remotely Sensed Imagery and Change Detectionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Presence of rapidly degrading permafrost plateaus in south-central Alaska

et al. 2016

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Permafrost Hydrology

Hinzman

Kane

Woo

2005

Encyclopedia of Hydrological Sciences

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Permafrost is earth material that has temperature at or below 0°C for at least two consecutive summers. Above the permafrost is the active layer, a zone that freezes in winter and thaws in summer. Even though the principles governing water movement in permafrost areas are the same as those in more temperate regions, interactions of extremes in climate and the land surface characteristics render permafrost hydrology different from the hydrology of temperate latitudes. Ice‐rich permafrost prevents infiltration of rainfall or snowmelt water, often maintaining a moist to saturated active layer where the permafrost table is shallow. Most hydrologic activities are confined above ground or in the thin active layer, which supplies summer moisture to plants and for evaporative flux. Limited storage capacity of the thawed zone does not support extended baseflow in a stream, though the proportion of baseflow increases as the percentage of permafrost extent decreases. In areas where permafrost is discontinuous or where it has thawed substantially near the surface, local hydrology may display a marked different character as there are stronger exchanges between the surface water and the ground water system, or water may drain laterally resulting in drier surface conditions. Runoff paths range from interhummock cracks, soil pipes, water tracks to distinct channels; and permafrost affects the ground water and contaminant migration pathways. Understanding the interdependence of permafrost, hydrology, and ecosystems is critically important to enable accurate projections of future conditions in the high latitudes.

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Influences of glacier melt and permafrost thaw on the age of dissolved organic carbon in the Yukon River basin

Aiken

Spencer

Striegl

et al. 2014

Global Biogeochemical Cycles

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Responses of near-surface permafrost and glacial ice to climate change are of particular significance for understanding long-term effects on global carbon cycling and carbon export by high-latitude northern rivers. Here we report Δ 14 C-dissolved organic carbon (DOC) values and dissolved organic matter optical data for the Yukon River, 15 tributaries of the Yukon River, glacial meltwater, and groundwater and soil water end-member sources draining to the Yukon River, with the goal of assessing mobilization of aged DOC within the watershed. Ancient DOC was associated with glacial meltwater and groundwater sources. In contrast, DOC from watersheds dominated by peat soils and underlain by permafrost was typically enriched in Δ 14 C indicating that degradation of ancient carbon stores is currently not occurring at large enough scales to quantitatively influence bulk DOC exports from those landscapes. On an annual basis, DOC exported was predominantly modern during the spring period throughout the Yukon River basin and became older through summer-fall and winter periods, suggesting that contributions of older DOC from soils, glacial meltwaters, and groundwater are significant during these months. Our data indicate that rapidly receding glaciers and increasing groundwater inputs will likely result in greater contributions of older DOC in the Yukon River and its tributaries in coming decades.

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Cited by 627 publications

References 42 publications

Presence of rapidly degrading permafrost plateaus in south-central Alaska

Presence of rapidly degrading permafrost plateaus in south-central Alaska

Permafrost Hydrology

Influences of glacier melt and permafrost thaw on the age of dissolved organic carbon in the Yukon River basin

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