Linking tundra vegetation, snow, soil temperature, and permafrost

Grünberg, Inge; Wilcox, Evan J.; Zwieback, Simon; Marsh, Philip; Boike, Julia

doi:10.5194/bg-2020-88

Cited by 5 publications

(4 citation statements)

References 21 publications

(34 reference statements)

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“…At PRH and NBH, scenarios with deeper snow (drift to the site) experienced significant warming of ~0.02 °C/year and MAGT varied by up to 4 °C at PRH and by 6 °C at NBH (Figure 4). These results support studies implicating snow accumulation as a driver of permafrost thaw (Grünberg et al 2020;Jafarov et al 2018;O'Neill and Burn 2017) and demonstrates the sensitivity of ground temperatures to snow thickness modifications in coastal Subarctic mountains.…”

Section: Discussionsupporting

confidence: 88%

Modelled Soil Temperature Sensitivity to Variable Snow and Vegetation Conditions in Low-Relief Coastal Mountains, Nunatsiavut and NunatuKavut, Labrador

Tutton¹,

Way²,

Beddoe³

et al. 2021

Preprint

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Understanding permafrost vulnerability and resilience to climate warming is critical for predicting impacts on northern communities and ecosystems. The thermal characteristics of near-surface permafrost are influenced by effects from overlying vegetation and snow cover, both of which are changing in northern environments. The association between vegetation and snow is important in the coastal mountains of Labrador, northeast Canada, because of high annual snowfall totals and greening tundra biomes. In this study, we present a series of one-dimensional simulations using the Northern Ecosystem Soil Temperature (NEST) model to characterize ground thermal conditions at two field sites (Nain, Nunatsiavut & Pinware, NunatuKavut) along the Labrador coast. NEST simulations covering 1979-2019 were run using ERA5 atmospheric reanalysis for three ecotypes (tundra, shrub, treed) with three different snow accumulation regimes (snow drifting away from site, no snow drift, snow drifting to site). At Nain, perennially frozen ground was present for all three ecotypes when snow cover was kept thin (drifting away) but was largely absent for the ecotypes when snow accumulation was higher. At Pinware, frozen ground was mostly absent except where snow cover was shallow (wind drifting away). For low-snow simulations, frozen bodies (< 20 m) persisted in all ecotypes during cold periods but only remained intact following warmer years for treed ecotypes. These results highlight the importance of spatial and temporal variability in snow cover on ground thermal regimes in coastal Labrador.

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Section: Discussionsupporting

confidence: 88%

Modelled Soil Temperature Sensitivity to Variable Snow and Vegetation Conditions in Low-Relief Coastal Mountains, Nunatsiavut and NunatuKavut, Labrador

Tutton¹,

Way²,

Beddoe³

et al. 2021

Preprint

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“…If continued climate change favours the establishment and recruitment of alder over dwarf birch, we would expect a further enhancement of greening trends. It is also likely that enhanced growth and recruitment of alder would increase the amount of snow being trapped throughout the winter, thus creating a positive feedback for future growth and survival (Grünberg et al 2020).…”

Section: Implications Of Changementioning

confidence: 99%

Recent greening driven by species-specific shrub growth characteristics in Nunatsiavut, Labrador, Canada

et al. 2021

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Satellite remote sensing is a popular approach for identifying vegetation change in northern environments; however, disentangling ecological processes causing variability in spectral indices remains a challenge. Here, we aim to determine how shrub characteristics differ between low and rapidly greening areas near Nain, Nunatsiavut, Canada. Using a cross-scale approach, we combined remotely sensed spectral greening trends (Normalized Difference Vegetation Index; Landsat Collection 1; 1985-2018) with shrub dynamics derived from ring-widths of green alder (Alnus alnobetula) and dwarf birch (Betula glandulosa). Differentiation of spectral greening classes appears to be driven by the distribution of shrub species. Alder were taller, grew faster, had more recent stem initiation than dwarf birch, and were dominant in rapid greening subplots. In low greening subplots, alders were co-dominant with dwarf birch, whose dominant stems initiated more gradually, were shorter, and had lower rates of vertical growth. The radial growth of both shrub species was favoured by warm winter temperatures and precipitation, whereas rapid greening alder was also favoured by warm summer temperatures. Further shrub growth will likely be enhanced under continued climate warming if moisture does not become limiting. This research demonstrates the importance of species identity in determining rates of spectral greening in northern environments.

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“…3.5). Shrub expansion can have multi-directional hydrological impacts (Grunberg et al, 2020), including shrub-snow interactions (Sect. 3.2) and increasing ET (Sect.…”

Section: Northern Vegetation Wildfire and Loss Of Ecological Resilimentioning

confidence: 99%

Summary and synthesis of Changing Cold Regions Network (CCRN) research in the interior of western Canada – Part 2: Future change in cryosphere, vegetation, and hydrology

DeBeer¹,

Wheater²,

Pomeroy³

et al. 2020

Preprint

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Abstract. The interior of western Canada, like many similar cold mid- to high-latitude regions worldwide, is undergoing extensive and rapid climate and environmental change, which may accelerate in the coming decades. Understanding and predicting changes in coupled climate–land–hydrological systems are crucial to society, yet limited by lack of understanding of changes in cold region process responses and interactions, along with their representation in most current generation land surface and hydrological models. It is essential to consider the underlying processes and base predictive models on the proper physics, especially under conditions of non-stationarity where the past is no longer a reliable guide to the future and system trajectories can be unexpected. These challenges were forefront in the recently completed Changing Cold Regions Network (CCRN), which assembled and focused a wide range of multi-disciplinary expertise to improve the understanding, diagnosis, and prediction of change over the cold interior of western Canada. CCRN advanced knowledge of fundamental cold region ecological and hydrological processes through observation and experimentation across a network of highly instrumented research basins and other sites. Significant efforts were made to improve the functionality and process representation, based on this improved understanding, within the fine-scale Cold Regions Hydrological Modelling (CRHM) platform and the large-scale Modélisation Environmentale Communautaire (MEC) – Surface and Hydrology (MESH) model. These models were, and continue to be, applied under past and projected future climates, and under current and expected future land and vegetation cover configurations to diagnose historical change and predict possible future hydrological responses. This second of two articles synthesizes the nature and understanding of cold region processes and Earth system responses to future climate, as advanced by CCRN. These include changing precipitation and moisture feedbacks to the atmosphere; altered snow regimes, changing balance of snowfall and rainfall, and glacier loss; vegetation responses to climate and the loss of ecosystem resilience to wildfire and disturbance; thawing permafrost and its influence on landscapes and hydrology; groundwater storage and cycling, and its connections to surface water; and stream and river discharge as influenced by the various drivers of hydrological change. Collective insights, expert elicitation, and model application are used to provide a synthesis of this change over the CCRN region for the late-21st century.

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Linking tundra vegetation, snow, soil temperature, and permafrost

Cited by 5 publications

References 21 publications

Modelled Soil Temperature Sensitivity to Variable Snow and Vegetation Conditions in Low-Relief Coastal Mountains, Nunatsiavut and NunatuKavut, Labrador

Modelled Soil Temperature Sensitivity to Variable Snow and Vegetation Conditions in Low-Relief Coastal Mountains, Nunatsiavut and NunatuKavut, Labrador

Recent greening driven by species-specific shrub growth characteristics in Nunatsiavut, Labrador, Canada

Summary and synthesis of Changing Cold Regions Network (CCRN) research in the interior of western Canada – Part 2: Future change in cryosphere, vegetation, and hydrology

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