Why and How to Study a Snowcover

Pruitt, William O.

doi:10.22621/cfn.v119i1.90

Cited by 12 publications

(8 citation statements)

References 26 publications

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“…the slope demonstrated stability for at least three days: 0.15 ≤ slope ≤ 0.15), given that the first snowfall with accumulation of at least 10 cm had occurred on or prior to that day (figure 2). Although Pruitt (2005) identified 20 cm as the minimum depth required for subnivium establishment, we found evidence for stabilized temperatures at depths less than this amount when analyzing ground temperatures at hourly time scales. Therefore, we used a threshold depth of 10 cm to include these shorter-term stabilizations and their potential effects on subnivium establishment.…”

Section: Establishment Maintenance and Disintegration Of The Subniviumcontrasting

confidence: 70%

“…This movement of vapor reduces the size of the ice crystals in the bottommost snow layer, creating a network of loosely-connected crystals whose low density traps heat released from the soil (Marchand 2013). When snow depths are sufficiently high, the low thermal conductivity of the snowpack insulates the subnivium, creating a warmer and more stable microclimate compared to external air temperatures (Pruitt 2005).…”

Section: Introductionmentioning

confidence: 99%

“…We investigated the phenology of the subnivium across three different cover types (coniferous forests, deciduous forests, and open sites) and three latitudinal ranges in the North American Great Lakes Region. While previous work on the subnivium has focused on the role of threshold depth (Pruitt 2005) and density (Marchand 2013), the life cycle of this ephemeral habitat has not been fully explored. Our goal was to quantify, for the first time, three critical phenophases of the subnivium: establishment, maintenance, and disintegration, and to evaluate how latitude and land cover mediate these phenophases.…”

Section: Introductionmentioning

confidence: 99%

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The phenology of the subnivium

Thompson

Zuckerberg

Porter

et al. 2018

Environ. Res. Lett.

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Section: Establishment Maintenance and Disintegration Of The Subniviumcontrasting

confidence: 70%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The phenology of the subnivium

Thompson

Zuckerberg

Porter

et al. 2018

Environ. Res. Lett.

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“…Ramsonde penetrometers are often used in studies concerning reindeer ecology (Tucker and others 1991; Nellemann 1996; Nellemann and others 2000). However, because of the ram's large mass (1.17 kg), and the total weight of the instrument (2.12 kg), it is not well suited for very soft snow (Pruitt 2005) where the crucial factor is not hardness, but depth (Heggberget and others 2002). 30 snow samples were weighed to determine the bulk density and thickness of different layers from 21 locations.…”

Section: Methodsmentioning

confidence: 99%

Sámi traditional ecological knowledge as a guide to science: snow, ice and reindeer pasture facing climate change

Riseth¹,

Tømmervik

Helander-Renvall

et al. 2010

Polar Record

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Scientific studies of challenges of climate change could be improved by including other sources of knowledge, such as traditional ecological knowledge (TEK), in this case relating to the Sámi. This study focuses on local variations in snow and ice conditions, effects of the first durable snow, and long term changes in snow and ice conditions as pre-requisites for understanding potential future changes. Firstly, we characterised snow types and profiles based on Sámi categories and measured their density and hardness. Regression analysis showed that density can explain much of the variation in hardness, while snow depth was not significantly correlated with hardness. Secondly, we found that whether it is dry/cold or warm/wet around the fall of the first durable snow is, according to Sámi reindeer herders, crucial information for forecasting winter grazing conditions, but this has had limited focus within science. Thirdly, elderly herders’ observations of changes in snow and ice conditions by ‘reading nature’ can aid reinterpretation of meteorological data by introducing researchers to alternative perspectives. In conclusion we found remarkable agreement between scientific measurements and Sámi terminology. We also learnt that TEK/science cooperation has much potential for climate change studies, though time and resources are needed to bridge the gap between knowledge systems. In particular, TEK attention to shifts in nature can be a useful guide for science.

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“…After controlling for migration start time, we found that higher wind speeds were associated with shorter migration durations. During winter and spring months, wind over snow leads to the hard-packed snow known locally as upsik (Pruitt 2005). Landscapes covered by hard snowpacks are measurably more difficult for caribou to forage in than those with soft snow (Collins and Smith 1991), but easier to move on than deep, wet snow (Henshaw 1968), both of which contribute to faster migrations.…”

Section: Migration Phenology and Climatementioning

confidence: 99%

Tactical departures and strategic arrivals: Divergent effects of climate and weather on caribou spring migrations

et al. 2019

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The Arctic has been warming rapidly, affecting ecological processes across the region. Caribou and reindeer (Rangifer tarandus) is a keystone Arctic species undergoing declines in many parts of its range, but definitive links between climate and populations remain elusive. The conspicuous and dramatic mass migration of many caribou populations, during which nearly all pregnant females move from wintering ranges to calving grounds shortly before giving birth, may be an important link between climate and caribou populations. The drivers of migration, however, are similarly mysterious. It is unknown, for example, whether caribou respond to immediate phenological cues, anticipate conditions on calving grounds, or are driven by lagged effects related to physical condition. To investigate the drivers of migration, we analyzed movement data from over 1000 individual caribou from seven major herds, spanning 3000 km across Alaska, Yukon, Northwest Territories (NWT), and Nunavut in Canada, from 1995 to 2017. We developed a hierarchical model to estimate migration departure and arrival times, and analyzed these variables against global climate indices and local weather conditions, exploring immediate and lagged effects, as well as snowmelt timing and vegetation indices. We discovered a continent‐wide synchrony in spring migration departure times, driven mainly by large‐scale, ocean‐driven climate indices (Pacific Decadal Oscillation, Arctic Oscillation, and North Atlantic Oscillation). However, we also found that the speed of migration was highly plastic with later migration departure times followed by shorter migration durations. This plasticity made arrival timing independent of departure timing and its respective drivers. Rather, arrival timing depended strongly on weather conditions from the previous summer: cooler and windier summers generally led to earlier arrival at calving grounds the following year. We suggest that maternal body condition, mainly influenced by conditions that limit insect harassment, is a major factor for earlier spring migration arrival timing, and therefore earlier calving and higher survival rates. We place these results in the context of mechanistic links between climate and caribou population dynamics. Long‐term and large‐scale observations of migratory animals can provide insights into the mechanisms by which long‐distance, collective migrants may adapt to dynamic and unpredictable environments.

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Why and How to Study a Snowcover

Cited by 12 publications

References 26 publications

The phenology of the subnivium

The phenology of the subnivium

Sámi traditional ecological knowledge as a guide to science: snow, ice and reindeer pasture facing climate change

Tactical departures and strategic arrivals: Divergent effects of climate and weather on caribou spring migrations

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