Effect of summer snow cover on the active layer thermal regime and thickness on CALM-S JGM site, James Ross Island, eastern Antarctic Peninsula

CATENA ◽  
2021 ◽  
Vol 207 ◽  
pp. 105608
Author(s):  
Filip Hrbáček ◽  
Zbyněk Engel ◽  
Michaela Kňažková ◽  
Jana Smolíková
Keyword(s):  
Snow Cover ◽  
Active Layer ◽  
Antarctic Peninsula ◽  
Thermal Regime ◽  
James Ross Island

scholarly journals Effect of ephemeral snow cover on the active layer thermal regime and thickness on CALM-S JGM site, James Ross Island, eastern Antarctic Peninsula

2021 ◽  
Author(s):  
Filip Hrbáček ◽  
Zbyněk Engel ◽  
Michaela Kňažková ◽  
Jana Smolíková
Keyword(s):  
Snow Cover ◽  
Active Layer ◽  
Antarctic Peninsula ◽  
Thermal Regime ◽  
Austral Summer ◽  
Monitoring Network ◽  
Active Layer Thickness ◽  
Ground Temperatures ◽  
James Ross Island ◽  
Ground Penetrating

Abstract. This study aims to assess the role of ephemeral snow cover on ground thermal regime and active layer thickness in two ground temperature measurement profiles on the Circumpolar Active Layer Monitoring Network – South (CALM-S) JGM site on James Ross Island, eastern Antarctic Peninsula during the high austral summer 2018. The snowstorm of 13–14 January created a snowpack of recorded depth of up to 38 cm. The snowpack remained on the study site for 12 days in total and covered 46 % of its area six days after the snowfall. It directly affected ground thermal regime in a study profile AWS-JGM while the AWS-CALM profile was snow-free. The thermal insulation effect of snow cover led to a decrease of mean summer ground temperatures on AWS-JGM by ca 0.5–0.7 °C. Summer thawing degree days at a depth of 5 cm decreased by ca 10 % and active layer was ca 5–10 cm thinner when compared to previous snow-free summer seasons. Surveying by ground penetrating radar revealed a general active layer thinning of up to 20 % in those parts of the CALM-S which were covered by snow of > 20 cm depth for at least six days.

scholarly journals Active layer thermal regime in two climatically contrasted sites of the Antarctic Peninsula region

2016 ◽  
Vol 42 (2) ◽  
pp. 457 ◽  
Author(s):  
F. Hrbáček ◽  
M. Oliva ◽  
K. Laska ◽  
J. Ruiz-Fernández ◽  
M. A. De Pablo ◽  
...  
Keyword(s):  
Active Layer ◽  
Antarctic Peninsula ◽  
Thermal Regime ◽  
Active Layer Thickness ◽  
Mean Annual Temperature ◽  
Climate Trends ◽  
Ground Temperatures ◽  
Air Temperatures ◽  
Discontinuous Permafrost ◽  
The Antarctic

Permafrost controls geomorphic processes in ice-free areas of the Antarctic Peninsula (AP) region. Future climate trends will promote significant changes of the active layer regime and permafrost distribution, and therefore a better characterization of present-day state is needed. With this purpose, this research focuses on Ulu Peninsula (James Ross Island) and Byers Peninsula (Livingston Island), located in the area of continuous and discontinuous permafrost in the eastern and western sides of the AP, respectively. Air and ground temperatures in as low as 80 cm below surface of the ground were monitored between January and December 2014. There is a high correlation between air temperatures on both sites (r=0.74). The mean annual temperature in Ulu Peninsula was -7.9 ºC, while in Byers Peninsula was -2.6 ºC. The lower air temperatures in Ulu Peninsula are also reflected in ground temperatures, which were between 4.9 (5 cm) and 5.9 ºC (75/80 cm) lower. The maximum active layer thickness observed during the study period was 52 cm in Ulu Peninsula and 85 cm in Byers Peninsula. Besides climate, soil characteristics, topography and snow cover are the main factors controlling the ground thermal regime in both areas.

scholarly journals Late-Holocene changes in character and behaviour of land-terminating glaciers on James Ross Island, Antarctica

2012 ◽  
Vol 58 (212) ◽  
pp. 1176-1190 ◽  
Author(s):  
Jonathan L. Carrivick ◽  
Bethan J. Davies ◽  
Neil F. Glasser ◽  
Daniel Nývlt ◽  
Michael J. Hambrey
Keyword(s):  
Climate Change ◽  
Sediment Transport ◽  
Surface Structure ◽  
Antarctic Peninsula ◽  
Thermal Regime ◽  
Late Holocene ◽  
Negative Mass ◽  
Warming Climate ◽  
James Ross Island ◽  
Geometric Changes

AbstractVirtually no information is available on the response of land-terminating Antarctic Peninsula glaciers to climate change on a centennial timescale. This paper analyses the topography, geomorphology and sedimentology of prominent moraines on James Ross Island, Antarctica, to determine geometric changes and to interpret glacier behaviour. The moraines are very likely due to a late-Holocene phase of advance and featured (1) shearing and thrusting within the snout, (2) shearing and deformation of basal sediment, (3) more supraglacial debris than at present and (4) short distances of sediment transport. Retreat of ~100 m and thinning of 15–20 m has produced a loss of 0.1 km3 of ice. The pattern of surface lowering is asymmetric. These geometrical changes are suggested most simply to be due to a net negative mass balance caused by a drier climate. Comparisons of the moraines with the current glaciological surface structure of the glaciers permits speculation of a transition from a polythermal to a cold-based thermal regime. Small land-terminating glaciers in the northern Antarctic Peninsula region could be cooling despite a warming climate.

Permafrost and active layer research on James Ross Island: An overview

2019 ◽  
Vol 9 (1) ◽  
pp. 20-36 ◽  
Author(s):  
Filip Hrbáček ◽  
Daniel Nývlt ◽  
Kamil Láska ◽  
Michaela Kňažková ◽  
Barbora Kampová ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Layer Thickness ◽  
Active Layer ◽  
Air Temperature ◽  
Thermal Regime ◽  
Ground Temperature ◽  
Active Layer Thickness ◽  
Near Surface ◽  
James Ross Island ◽  
The Mean

This study summarizes the current state of the active layer and permafrost research on James Ross Island. The analysis of climate parameters covers the reference period 2011–2017. The mean annual air temperature at the AWS-JGM site was -6.9°C (ranged from -3.9°C to -8.2°C). The mean annual ground temperature at the depth of 5 cm was -5.5°C (ranged from -3.3°C to -6.7°C) and it also reached -5.6°C (ranged from -4.0 to -6.8°C) at the depth of 50 cm. The mean daily ground temperature at the depth of 5 cm correlated moderately up to strongly with the air temperature depending on the season of the year. Analysis of the snow effect on the ground thermal regime confirmed a low insulating effect of snow cover when snow thickness reached up to 50 cm. A thicker snow accumulation, reaching at least 70 cm, can develop around the hyaloclastite breccia boulders where a well pronounced insulation effect on the near-surface ground thermal regime was observed. The effect of lithology on the ground physical properties and the active layer thickness was also investigated. Laboratory analysis of ground thermal properties showed variation in thermal conductivity (0.3 to 0.9 W m-1 K-1). The thickest active layer (89 cm) was observed on the Berry Hill slopes site, where the lowest thawing degree days index (321 to 382°C·day) and the highest value of thermal conductivity (0.9 W m-1 K-1) was observed. The clearest influence of lithological conditions on active layer thickness was observed on the CALM-S grid. The site comprises a sandy Holocene marine terrace and muddy sand of the Whisky Bay Formation. Surveying using a manual probe, ground penetrating radar, and an electromagnetic conductivity meter clearly showed the effect of the lithological boundary on local variability of the active layer thickness.

scholarly journals Frozen ground and snow cover monitoring in the South Shetland Islands, Antarctica: Instrumentation, effects on ground thermal behaviour and future research

2016 ◽  
Vol 42 (2) ◽  
pp. 475 ◽  
Author(s):  
M. A. De Pablo ◽  
M. Ramos ◽  
A. Molina ◽  
G. Vieira ◽  
M. A. Hidalgo ◽  
...  
Keyword(s):  
Thermal Behavior ◽  
Snow Cover ◽  
Active Layer ◽  
Antarctic Peninsula ◽  
Snow Water Equivalent ◽  
South Shetland Islands ◽  
Active Layer Thickness ◽  
The South ◽  
Shetland Islands ◽  
Snow Cover Duration

The study of the thermal behavior of permafrost and active layer on the South Shetland Islands, in the western side of the Antarctic Peninsula (Antarctica), has been our research topic since 1991, especially after 2006 when we established different active layer thickness and ground thermal monitoring sites of the CALM and GTN-P international networks of the International Permafrost Association. Along this period, the snow cover thickness did not change at those sites, but since 2010, we observed an elongation on the snow cover duration, with similar snow onset, but a delay on the snow offset. Due to the important effects of  snow cover on the ground thermal behavior, we started in late 2015 a new research project (PERMASNOW) focused on the accurate monitoring of the snow cover (duration, density, snow water equivalent and distribution), from very different approaches, including new instrumentation, pictures analysis and remote sensing on optical and radar bands. Also, this interdisciplinary and international research team intends to compare the snow cover and ground thermal behavior with other monitoring sites in the Eastern Antarctic Peninsula where the snow cover is minimum and remains approximately constant.

scholarly journals Sensitivity of active layer freezing process to snow cover in Arctic Alaska

2018 ◽  
Author(s):  
Yonghong Yi ◽  
John S. Kimball ◽  
Richard H. Chen ◽  
Mahta Moghaddam ◽  
Charles E. Miller
Keyword(s):  
Snow Cover ◽  
Water Content ◽  
Active Layer ◽  
Thermal Regime ◽  
Freezing Process ◽  
Organic Layer ◽  
Soil Organic Layer ◽  
Arctic Alaska ◽  
In Situ Observations

Abstract. The contribution of cold season soil respiration to Arctic-boreal carbon cycle and potential feedbacks to global climate system remain poorly quantified, partly due to a poor understanding of the changes in the soil thermal regime and liquid water content during the soil freezing process. Here, we characterized the processes controlling active layer freezing in Arctic Alaska using an integrated approach combining in-situ observations, local scale (~ 50 m) longwave radar retrievals from NASA Airborne P-band polarimetric SAR (PolSAR), and a remote sensing driven permafrost model. To better capture landscape variability in snow cover and its influence on soil thermal regime, we downscaled global coarse-resolution (~ 0.5°) reanalysis snow data using finer scale (500 m) MODIS (MODerate resolution Imaging Spectroradiometer) snow cover extent (SCE) observations. The downscaled 1-km snow depth dataset captured fine-scale variability associated with local topography, and compared well with in-situ observations across Alaska, with a mean RMSE of 0.16 m and bias of −0.01 m in Arctic Alaska, which was used to drive the permafrost model. We also used the in-situ soil dielectric constant (ɛ) profile measurements to guide model parameterization of soil organic layer and unfrozen water content curve. Across a 2° latitudinal zone along the Dalton highway in the Alaska North Slope, the model simulated mean zero-curtain period was generally consistent with in-situ observations (R: 0.6 ± 0.2; RMSE: 19 ± 6 days), which showed mean zero-curtain periods of 61 ± 11 to 73 ± 15 days from depths of 0.25 m to 0.45 m. Along the same transect, both the observed and model simulated zero-curtain periods were positively correlated (R > 0.55, p 

Active layer monitoring at CALM-S site near J.G.Mendel Station, James Ross Island, eastern Antarctic Peninsula

2017 ◽  
Vol 601-602 ◽  
pp. 987-997 ◽  
Author(s):  
Filip Hrbáček ◽  
Michaela Kňažková ◽  
Daniel Nývlt ◽  
Kamil Láska ◽  
Carsten W. Mueller ◽  
...  
Keyword(s):  
Active Layer ◽  
Antarctic Peninsula ◽  
James Ross Island
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