Coastal region of northern Alaska, Guidebook to permafrost and related features

Jorgenson, M. Torre

doi:10.14509/22762

Cited by 21 publications

(35 citation statements)

References 73 publications

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“…This mosaic of lakes, bogs, and permafrost plateaus then provides a challenge for integrating the C dynamics of ecosystems with widely varying C accumulation and loss rates across the broader landscape. In the boreal region of central Alaska with discontinuous permafrost, Jorgenson et al (2008) estimated that 5% of the region had thermokarst terrain and 62% had permafrost and that lowland areas had nearly half (35% of total area) of the permafrost and nearly all of the thermokarst (4%). For comparison, Pastick et al (2015) estimated that the similar Intermontane Boreal ecoregion had near-surface permafrost (upper 1 m) over 45% of the area.…”

Section: Regional Landscape Implicationsmentioning

confidence: 99%

Rapid carbon loss and slow recovery following permafrost thaw in boreal peatlands

Jones

Harden

O’Donnell

et al. 2016

Global Change Biology

119

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Permafrost peatlands store one-third of the total carbon (C) in the atmosphere and are increasingly vulnerable to thaw as high-latitude temperatures warm. Large uncertainties remain about C dynamics following permafrost thaw in boreal peatlands. We used a chronosequence approach to measure C stocks in forested permafrost plateaus (forest) and thawed permafrost bogs, ranging in thaw age from young (<10 years) to old (>100 years) from two interior Alaska chronosequences. Permafrost originally aggraded simultaneously with peat accumulation (syngenetic permafrost) at both sites. We found that upon thaw, C loss of the forest peat C is equivalent to ~30% of the initial forest C stock and is directly proportional to the prethaw C stocks. Our model results indicate that permafrost thaw turned these peatlands into net C sources to the atmosphere for a decade following thaw, after which post-thaw bog peat accumulation returned sites to net C sinks. It can take multiple centuries to millennia for a site to recover its prethaw C stocks; the amount of time needed for them to regain their prethaw C stocks is governed by the amount of C that accumulated prior to thaw. Consequently, these findings show that older peatlands will take longer to recover prethaw C stocks, whereas younger peatlands will exceed prethaw stocks in a matter of centuries. We conclude that the loss of sporadic and discontinuous permafrost by 2100 could result in a loss of up to 24 Pg of deep C from permafrost peatlands.

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Section: Regional Landscape Implicationsmentioning

confidence: 99%

Rapid carbon loss and slow recovery following permafrost thaw in boreal peatlands

Jones

Harden

O’Donnell

et al. 2016

Global Change Biology

119

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“…The Ecosystems map of Northern Alaska by Jorgenson and Heiner [25] (published 2003) is a map of local-scale ecosystems which combines vegetation structure from existing land cover maps with physiography, topography and bedrock characteristics. It covers Alaska north of the treeline and has a 30 m pixel resolution.…”

Section: Ecosystems Map Of Northern Alaskamentioning

confidence: 99%

Simplified Normalization of C-Band Synthetic Aperture Radar Data for Terrestrial Applications in High Latitude Environments

2018

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Synthetic aperture radar (SAR) applications often require normalization to a common incidence angle. Angular signatures of radar backscatter depend on surface roughness and vegetation cover, and thus differ, from location to location. Comprehensive reference datasets are therefore required in heterogeneous landscapes. Multiple acquisitions from overlapping orbits with sufficient incidence angle range are processed in order to obtain parameters of the location specific normalization function. We propose a simpler method for C-band data, using single scenes only. It requires stable dielectric properties (no variations of liquid water content). This method is therefore applicable for frozen conditions. Winter C-band data have been shown of high value for a number of applications in high latitudes before. In this paper we explore the relationship of incidence angle and Sentinel-1 backscatter across the tundra to boreal transition zone. A linear relationship (coefficient of determination R 2 = 0.64) can be found between backscatter and incidence angle dependence (slope of normalization function) as determined by multiple acquisitions on a pixel by pixel basis for typical land cover classes in these regions. This allows a simplified normalization and thus reduced processing effort for applications over larger areas.

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“…Semiarid boreal lowlands: the Yukon Flats region, Alaska, USA The Yukon Flats is a large alluvial basin located in the central Yukon River basin in the dry boreal zone of interior Alaska (Figure 1, Figure 2, Table I). The climate is continental subarctic (Gallant et al, 1995) with discontinuous to continuous permafrost underlying the more than 30 000 km 2 of the floodplains of the Yukon River and multiple tributaries (Jorgenson et al, 2008). Floodplain vegetation types include herbaceous vegetation, shrubs (willows (Salix spp.)…”

Section: Study Areasmentioning

confidence: 99%

Floodplain downed wood volumes: a comparison across three biomes

Lininger

Wohl

Sutfin

et al. 2016

Earth Surf Processes Landf

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Downed large wood (LW) in floodplains provides habitat and nutrients for diverse organisms, influences hydraulics and sedimentation during overbank flows, and affects channel form and lateral migration. Very few studies, however, have quantified LW volumes in floodplains that are unaltered by human disturbance. We compare LW volumes in relatively unaltered floodplains of semiarid boreal lowland, subtropical lowland, and semiarid temperate mountain rivers in the United States. Average volumes of downed LW are 42.3 m3 ha−1, 50.4 m3 ha−1, and 116.3 m3 ha−1 in the semiarid boreal, subtropical, and semiarid temperate sites, respectively. Observed patterns support the hypothesis that the largest downed LW volumes occur in the semiarid temperate mountain sites, which is likely linked to a combination of moderate‐to‐high net primary productivity, temperature‐limited decomposition rates, and resulting slow wood turnover time. Floodplain LW volumes differ among vegetation types within the semiarid boreal and semiarid temperate mountain regions, reflecting differences in species composition. Lateral channel migration and flooding influence vegetation communities in the semiarid boreal sites, which in turn influences floodplain LW loads. Other forms of disturbance such as fires, insect infestations, and blowdowns can increase LW volumes in the semiarid boreal and semiarid temperate mountain sites, where rates of wood decay are relatively slow compared with the subtropical lowland sites. Although sediment is the largest floodplain carbon reservoir, floodplain LW stores substantial amounts of organic carbon and can influence floodplain sediment storage. In our study sites, floodplain LW volumes are lower than those in adjacent channels, but are higher than those in upland (i.e. non‐floodplain) forests. Given the important ecological and physical effects of floodplain LW, efforts to add LW to river corridors as part of restoration activities, and the need to quantify carbon stocks within river corridors, we urge others to quantify floodplain and instream LW volumes in diverse environments. Copyright © 2016 John Wiley & Sons, Ltd.

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Coastal region of northern Alaska, Guidebook to permafrost and related features

Cited by 21 publications

References 73 publications

Rapid carbon loss and slow recovery following permafrost thaw in boreal peatlands

Rapid carbon loss and slow recovery following permafrost thaw in boreal peatlands

Simplified Normalization of C-Band Synthetic Aperture Radar Data for Terrestrial Applications in High Latitude Environments

Floodplain downed wood volumes: a comparison across three biomes

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