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Frapin, C., Albouy, C., Gilg, O., Christin, S., Angerbjörn, A., Fauteux, D. & Lecomte, N. (2022). Modeling the seasonal Arctic trophic network and the centrality of the Arctic fox.
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Frapin, C., Albouy, C., Gilg, O., Christin, S., Angerbjörn, A., Fauteux, D. &Amp; Lecomte, N. (2022). Modeling the seasonal Arctic terrestrial trophic network.
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. (2022). The Traill island model for lemming dynamics, how it compares to Fennoscandian vole dynamics models, and a proposed simplification (Vol. 2205.09441).
Abstract: The Traill island model of Gilg et al. (2003) is a landmark attempt at mechanistic modelling of the cyclic population dynamics of rodents, focusing on a high Arctic community. It models the dynamics of one prey, the collared lemming, and four predators : the stoat, the Arctic fox, the long-tailed skua and the snowy owl. In the present short note, we first summarize how the model works in light of theory on seasonally forced predator-prey systems, with a focus on the temporal dynamics of predation rates. We show notably how the impact of generalist predation, which is able here to initiate population declines, differs slightly from that of generalist predation in other mechanistic models of rodent-mustelid interactions such as Turchin & Hanski (1997). We then provide a low-dimensional approximation with a single generalist predator compartment that mimics the essential features of the Traill island model: cycle periodicity, amplitude, shape, as well as generalist-induced declines. This simpler model should be broadly applicable to model other lemming populations that predominantly grow under the snow during the winter period. Matlab computer codes for Gilg et al. (2003), its two-dimensional approximation, as well as alternative lemming population dynamics models are provided.
Keywords: Quantitative Biology – Populations and Evolution
Programme: 1036
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. (2022). The Microwave Snow Grain Size: A New Concept to Predict Satellite Observations Over Snow-Covered Regions (Vol. 3). Bachelor's thesis, , .
Keywords: microstructure microwave modeling porous media remote sensing snow
Programme: 1110,1177
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. (2022). Metamorphism of snow on Arctic sea ice during the melt season: impact on spectral albedo and radiative fluxes through snow (Vol. 16).
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Gautier Davesne, Daniel Fortier, Florent Domine. (2022). Properties and stratigraphy of polar ice patches in the Canadian High Arctic reveal their current resilience to warm summers (Vol. 8).
Abstract: Ice patches are ubiquitous in polar regions and are a key element for landscape evolution. We present new insights into polar desert ice patch formation based on snow and ice properties at Ward Hunt Island (Canadian High Arctic, 83°N). Our results demonstrate that ice patches are composed of two distinct units. The upper unit is characterized by very fine granular and bubbly ice with a clear oblique layering. By contrast, the lower unit is strikingly different with coarse crystals, lower porosity, and a high frequency of fractures. For both units, superimposed ice formation at the base of the deep snowpack stands out as the primary ice aggradation process. The distinct properties of the lower unit likely result from a long period of kinetic ice crystal growth indicating a minimum age of several hundred years. A radiocarbon date of 3 487 ± 20 cal BP suggests that ice patches could potentially date back to the late Holocene. This old ice was recently truncated during warmer summers between 2008 and 2012, but the ice patch quickly recovered its volume during cooler summers. The old age of the ice patches and their rapid regeneration after melt events suggest their resilience to current warmer summers.
Programme: 1042
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. (2022). On the energy budget of a low-Arctic snowpack (Vol. 16).
Abstract: Arctic landscapes are covered in snow for at least 6 months of the year. The energy balance of the snow cover plays a key role in these environments, influencing the surface albedo, the thermal regime of the permafrost, and other factors. Our goal is to quantify all major heat fluxes above, within, and below a low-Arctic snowpack at a shrub tundra site on the east coast of Hudson Bay in eastern Canada. The study is based on observations from a flux tower that uses the eddy covariance approach and from profiles of temperature and thermal conductivity in the snow and soil. Additionally, we compared the observations with simulations produced using the Crocus snow model. We found that radiative losses due to negative longwave radiation are mostly counterbalanced by the sensible heat flux, whereas the latent heat flux is minimal. At the snow surface, the heat flux into the snow is similar in magnitude to the sensible heat flux. Because the snow cover stores very little heat, the majority of the upward heat flux in the snow is used to cool the soil. Overall, the model was able to reproduce the observed energy balance, but due to the effects of atmospheric stratification, it showed some deficiencies when simulating turbulent heat fluxes at an hourly timescale.
Programme: 1042
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Georg Lackner, Florent Domine, Daniel F. Nadeau, Matthieu Lafaysse, Marie Dumont. (2022). (Vol. 16).
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. (2022). HD 28109 hosts a trio of transiting Neptunian planets including a near-resonant pair, confirmed by ASTEP from Antarctica (Vol. 515).
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Ghislain Picard, Marion Leduc-Leballeur, Alison F. Banwell, Ludovic Brucker, Giovanni Macelloni. (2022). The sensitivity of satellite microwave observations to liquid water in the Antarctic snowpack (Vol. 16).
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