Records |
Author |
Gautier Davesne, Daniel Fortier, Florent Domine |
Title |
Properties and stratigraphy of polar ice patches in the Canadian High Arctic reveal their current resilience to warm summers |
Type |
Journal |
Year |
2022 |
Publication |
Arctic Science |
Abbreviated Journal |
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Volume |
8 |
Issue |
2 |
Pages |
414-449 |
Keywords |
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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. |
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1042 |
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yes |
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Serial |
8399 |
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Author |
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Title |
On the energy budget of a low-Arctic snowpack |
Type |
Journal |
Year |
2022 |
Publication |
The Cryosphere |
Abbreviated Journal |
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Volume |
16 |
Issue |
1 |
Pages |
127-142 |
Keywords |
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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. |
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1042 |
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Edition |
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ISSN |
1994-0416 |
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yes |
Call Number |
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Serial |
8408 |
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Author |
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Title |
Investigating the Role of Shrub Height and Topography in Snow Accumulation on Low-Arctic Tundra using UAV-Borne Lidar |
Type |
Journal |
Year |
2023 |
Publication |
Journal of Hydrometeorology |
Abbreviated Journal |
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Volume |
24 |
Issue |
5 |
Pages |
853-871 |
Keywords |
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Abstract |
Abstract Expanding shrubs in the Arctic trap blowing snow, increasing snow height and accelerating permafrost warming. Topography also affects snow height as snow accumulates in hollows. The respective roles of topography and erect vegetation in snow accumulation were investigated using a UAV-borne lidar at two nearby contrasted sites in northern Quebec, Canada. The North site featured tall vegetation up to 2.5 m high, moderate snow height, and smooth topography. The South site featured lower vegetation, greater snow height, and rougher topography. There was little correlation between topography and vegetation height at both sites. Vegetation lower than snow height had very little effect on snow height. When vegetation protruded above the snow, snow height was well correlated with vegetation height. The topographic position index (TPI) was well correlated with snow height when it was not masked by the effect of protruding vegetation. The North site with taller vegetation therefore showed a good correlation between vegetation height and snow height, R2 = 0.37, versus R2 = 0.04 at the South site. Regarding topography, the reverse was observed between TPI and snow height, with R2 = 0.29 at the North site and R2 = 0.67 at the South site. The combination of vegetation height and TPI improved the prediction of snow height at the North site (R2 = 0.59) but not at the South site because vegetation height has little influence there. Vegetation was therefore the main factor determining snow height when it protruded above the snow. When it did not protrude, snow height was mostly determined by topography. Significance Statement Wind-induced snow drifting is a major snow redistribution process in the Arctic. Shrubs trap drifting snow, and drifting snow accumulates in hollows. Determining the respective roles of both these processes in snow accumulation is required to predict permafrost temperature and its emission of greenhouse gases, because thicker snow limits permafrost winter cooling. Using a UAV-borne lidar, we have determined snow height distribution over two contrasted sites in the Canadian low Arctic, with varied vegetation height and topography. When snow height exceeds vegetation height, topography is a good predictor of snow height, with negligible effect of buried vegetation. When vegetation protrudes above the snow, combining both topography and vegetation height is required for a good prediction of snow height. |
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1042 |
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Edition |
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ISSN |
1525-7541, 1525-755X |
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Approved |
yes |
Call Number |
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Serial |
8541 |
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Author |
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Title |
Metamorphism of snow on Arctic sea ice during the melt season: impact on spectral albedo and radiative fluxes through snow |
Type |
Journal |
Year |
2022 |
Publication |
The Cryosphere |
Abbreviated Journal |
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Volume |
16 |
Issue |
9 |
Pages |
3431-3449 |
Keywords |
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Abstract |
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Programme |
1042 |
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ISSN |
1994-0416 |
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yes |
Call Number |
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Serial |
8577 |
Permanent link to this record |
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Author |
Georg Lackner, Florent Domine, Daniel F. Nadeau, Matthieu Lafaysse, Marie Dumont |
Title |
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Type |
Journal |
Year |
2022 |
Publication |
The Cryosphere |
Abbreviated Journal |
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Volume |
16 |
Issue |
8 |
Pages |
3357-3373 |
Keywords |
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Abstract |
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Programme |
1042 |
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Edition |
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ISSN |
1994-0416 |
ISBN |
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Approved |
yes |
Call Number |
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Serial |
8588 |
Permanent link to this record |
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Author |
A. Ola, D. Fortier, S. Coulombe, J. Comte, F. Domine |
Title |
The Distribution of Soil Carbon and Nitrogen Stocks Among Dominant Geomorphological Terrain Units in Qarlikturvik Valley, Bylot Island, Arctic Canada |
Type |
Journal |
Year |
2022 |
Publication |
Journal of Geophysical Research: Biogeosciences |
Abbreviated Journal |
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Volume |
127 |
Issue |
7 |
Pages |
e2021JG006750 |
Keywords |
alluvial fan Arctic permafrost polygon tundra |
Abstract |
Soils of circumpolar regions store large amounts of carbon (C) and are a crucial part of the global C cycle. Yet, little is known about the distribution of soil C stocks among geomorphological terrain units of glacial valleys in the Arctic. Soil C and nitrogen (N) content for the top 100 cm of the dominant vegetated geomorphological terrain units (i.e., alluvial fans, humid polygons, mesic polygons) at Qarlikturvik Valley, Bylot Island, Canada have been analyzed. Soil C content was greatest in humid low-center ice-wedge polygons (82 kg m?2), followed by mesic flat-center ice-wedge polygons (40 kg m?2), and alluvial fan area (16 kg m?2), due to prevailing geomorphological processes, differences in vegetation and soil characteristics, as well as permafrost processes. Soil N content was greatest in humid polygons (4 kg m?2), followed by mesic polygons (2 kg m?2), and alluvial fan area (1 kg m?2). Vertically, C and N decreased with increasing depth except for a peak in C at depth in humid polygons, a likely result of past changes in vegetation cover. At Qarlikturvik Valley, which has a size of 121.7 km2, alluvial fans store 0.226 Tg organic C and humid and mesic polygons store 1.643 and 0.218 Tg organic C, respectively in the top 100 cm of soil. Findings like these are important to further constrain pan-Arctic soil C and N stock estimates and thus climate models. |
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1042 |
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ISSN |
2169-8961 |
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yes |
Call Number |
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Serial |
8594 |
Permanent link to this record |
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Author |
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Title |
Vegetation type is an important predictor of the arctic summer land surface energy budget |
Type |
Journal |
Year |
2022 |
Publication |
Nature Communications |
Abbreviated Journal |
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Volume |
13 |
Issue |
1 |
Pages |
6379 |
Keywords |
Atmospheric dynamics Climate and Earth system modelling Cryospheric science Ecosystem ecology Phenology |
Abstract |
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Programme |
1042 |
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Edition |
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ISSN |
2041-1723 |
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yes |
Call Number |
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Serial |
8599 |
Permanent link to this record |
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Author |
Y. Klanten, R.-M. Couture, K. S. Christoffersen, W. F. Vincent, D. Antoniades |
Title |
Oxygen Depletion in Arctic Lakes: Circumpolar Trends, Biogeochemical Processes, and Implications of Climate Change |
Type |
Journal |
Year |
2023 |
Publication |
Global Biogeochemical Cycles |
Abbreviated Journal |
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Volume |
37 |
Issue |
5 |
Pages |
e2022GB007616 |
Keywords |
Arctic lakes biochemical processes climate change dissolved oxygen freshwater meta-analysis |
Abstract |
Polar amplification of climate change has the potential to cause large-scale shifts in the dissolved oxygen (DO) dynamics of Arctic lakes, with implications for fish survival, greenhouse gas production, and drinking water quality. While DO is also a sentinel of environmental changes of physical, chemical, and biological nature (e.g., ice cover, temperature, dissolved organic carbon, photosynthesis, and respiration), no synthesis exists of current knowledge of DO dynamics across the diverse freshwater systems of the Arctic. We thus conducted a systematic review of the literature that yielded DO data from 167 sites north of the Subarctic limit (based on vegetation zones), spanning 76 years and including 40 sites with time series. The compilation revealed insufficient observations for adequate representativeness of oxygen dynamics over Arctic ecosystem gradients. We described the main processes controlling DO budgets of Arctic lakes and tested relationships of summer oxygen depletion with maximum depth and latitude. The meta-analysis showed that most sites with low O2 concentrations were shallow (<10 m) and situated toward the southern end of the latitudinal gradient. Permanently stratified lakes with deep, perennially anoxic basins were located toward the northern end of the gradient. By way of a conceptual model, we identified the direct and indirect drivers and mechanisms that lead to changes in oxygen budgets in the context of the warming Arctic. This comprehensive update on available data allowed us to suggest future research directions and recommend the use of moored instruments for continuous all-season observations, combined with modeling, remote sensing, and paleo-reconstructions. |
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1042 |
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ISSN |
1944-9224 |
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yes |
Call Number |
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Serial |
8633 |
Permanent link to this record |
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Author |
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Title |
Shedding Light on a Dark Lake: How the Sun Transforms the Chemistry of Lakes |
Type |
Peer-reviewed symposium |
Year |
2022 |
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1042 |
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yes |
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Serial |
8694 |
Permanent link to this record |
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Author |
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Title |
Autonomous Optical Sensor to Study the Evolution of Snow Density in Polar Environment |
Type |
Peer-reviewed symposium |
Year |
2022 |
Publication |
Technical digest series |
Abbreviated Journal |
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Volume |
Proceedings of Imaging and Applied Optics Congress |
Issue |
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Pages |
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Keywords |
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Abstract |
A system to study the evolution of snow density is presented here with an emphasis on the system itself and on the efforts to make a robust system for harsh environments. The metric to deduce the density of the snow is the measurement of the concentration of ambient air oxygen using a tunable diode laser spectroscopy technique: the first harmonic phase angle wavelength modulation spectroscopy. For greater robustness, the system is equipped with an embedded calibration system and is built for a smart power consumption. |
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1042 |
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yes |
Call Number |
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Serial |
8748 |
Permanent link to this record |