Temporal evolution of physical and dielectric properties of sea ice and snow during the early melt season: observations from SIMS ’90 experiment

AbstractThe first field experiment in the 5 year seasonal Sea Ice Monitoring Site (SIMS) program was conducted in Resolute Passage, Canadian Eastern Arctic, between 15 May and 8 June 1990. This period signals the early melt season of sea ice in that region. A standard array of ice and snow measurements was collected on a daily basis from first-year and multi-year ice to monitor temporal evolution. Measurements included ice salinity, ice temperature and ice-surface roughness, snow salinity, snow temperature, snow density and snow depth. The complex dielectric constant of sea ice was computed from these measurements. Rapid desalination of first-year ice was noticed in the surface layer. Towards the end of the experiment period, salinities of the snow-hoar layer were higher than those of the ice-surface layer. Variation in air temperature is replicated by ice-surface temperature but not by the salinity or dielectric properties. No temporal variation in permittivity and dielectric loss was observed for first-year ice, but a slight increase in both parameters was observed for multi-year ice. As a result, a slight decrease in the microwave-penetration depth was observed for multi-year ice. Physical properties of ice and snow were compared against results obtained from other experiments conducted in different ice-formation regions in the late winter and in the early melt season.

Download Full-text

Physical properties and spatial distribution of the sea ice surface layer (SSL/snow) during the autumn phase of the MOSAiC expedition

10.5194/egusphere-egu21-1467 ◽

2021 ◽

Author(s):

Ruzica Dadic ◽

Martin Schneebeli ◽

Henna-Reeta Hannula ◽

Amy Macfarlane ◽

Roberta Pirazzini

Keyword(s):

Surface Layer ◽

Spatial Distribution ◽

Sea Ice ◽

Physical Properties ◽

Surface Scattering ◽

Climate Feedback ◽

Energy Fluxes ◽

Scattering Layer ◽

Near Surface ◽

Ice Surface

<p>Snow cover dominates the thermal and optical properties of sea ice and the energy fluxes between the ocean and the atmosphere, yet data on the physical properties of snow and its effects on sea ice are limited. This lack of data leads to two significant problems: 1) significant biases in model representations of the sea ice cover and the processes that drive it, and 2) large uncertainties in how sea ice influences the global energy budget and the coupling of climate feedback. The &#160;MOSAiC research initiative enabled the most extensive data collection of snow and surface scattering layer (SSL) properties over sea ice to date. During leg 5 of the MOSAiC expedition, we collected multi-scale (microscale to 100-m scale) measurements of the surface layer (snow/SSL) over first year ice (FYI) and MYI on a daily basis. The ultimate goal of our measurements is to determine the spatial distribution of physical properties of the surface layer. During leg 5 of the MOSAiC expedition, that surface layer changed from the &#160;surface scattering layer (SSL), &#160; characteristic for the melt season, to an early autumn snow pack. Here, &#160;we will present data showing both a) the physical properties and the spatial distribution of the SSL during the late melt season and b) the transition of the sea ice surface from the SSL to the fresh autumn snowpack. The structural properties of this transition period are poorly documented, and this season is critical &#160;for the initialization of sea ice and snow models. Furthermore, these data are crucial to interpret simultaneous observations of surface energy fluxes, surface optical and remote sensing data (microwave signals in particular), near-surface biochemical activity, and to understand the sea ice &#160;processes that occur as the sea ice transitions from melting to freezing.</p>

Download Full-text

Seasonal evolution and salt/freshwater fluxes of first-year sea ice: Comparison between pack ice and landfast sea ice

10.5194/egusphere-egu21-10798 ◽

2021 ◽

Author(s):

Marc Oggier ◽

Hajo Eicken ◽

Robert Rember ◽

Allison Fong ◽

Dmitry V. Divine ◽

...

Keyword(s):

Sea Ice ◽

Ice Cores ◽

Upper Ocean ◽

First Year ◽

Ice Melt ◽

Ice Surface ◽

Freshwater Fluxes ◽

Exchange Processes ◽

Bulk Salinity ◽

Landfast Sea Ice

<p>Sea ice affects the exchange of energy and matter between the atmosphere and the ocean from local to hemispheric scales. Salt fluxes across the ice-ocean interface that drive thermohaline mixing beneath growing sea ice are important elements of upper ocean nutrient and carbon exchange. Sea-ice melt releases freshwater into the upper ocean and results in formation of melt ponds that affect gas and energy transfer across the atmosphere-ice interface. The Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) provided an opportunity to follow sea-ice evolution and exchange processes over a full seasonal cycle in a rapidly changing ice cover. To this end, approximately 25 sea-ice cores were collected at 2 distinct sites, representing first-year and multi-year ice, to monitor physical, biological and geochemical processes relevant to atmosphere-ice-ocean exchange processes. Here we compare the growth and decay of first-year ice in the Central Arctic during the winter 2019-2020 to that of landfast first-year ice at Utqia&#289;vik, Alaska, from 1998 to 2016. Ice stratigraphy was similar at both sites with about 15 cm of granular ice on top of columnar ice, with a comparable growth history with a similar maximum ice thickness of 1.6-1.7 m. We aggregated the sea-ice bulk salinity and temperature profiles using a degree-day approach, and examined brine and freshwater fluxes at lower and upper interfaces of the ice, respectively. Preliminary results show lower sea-ice bulk salinity during the growth season and greater desalination at the ice surface during the melt season at the MOSAiC floe in comparison to Utqia&#289;vik.</p>

Download Full-text

A Field Study of Brine Drainage and Oil Entrainment in First-Year Sea Ice

Journal of Glaciology ◽

10.3189/s0022143000014477 ◽

1979 ◽

Vol 22 (88) ◽

pp. 473-502 ◽

Cited By ~ 5

Author(s):

Seelye Martin

Keyword(s):

Sea Ice ◽

Growth And Development ◽

Salt Transport ◽

First Year ◽

Field Observations ◽

Melt Pond ◽

Ice Surface ◽

Melt Ponds ◽

Brine Channel ◽

Horizontal Layers

AbstractFrom field observations this paper describes the growth and development of first-year sea ice and its interaction with petroleum. In particular, when sea ice initially forms, there is an upward salt transport so that the ice surface has a highly saline layer, regardless of whether the initial ice is frazil, columnar, or slush ice. When the ice warms in the spring, because of the eutectic condition, the surface salt liquifies and drains through the ice, leading to the formation of top-to-bottom brine channels and void spaces in the upper part of the ice. If oil is released beneath winter ice, then the oil becomes entrained in thin lenses within the ice. In the spring, this oil flows up to the surface through the newly-opened brine channels and distributes itself within the brine-channel feeder systems, on the ice surface, and in horizontal layers in the upper part of the ice. The paper shows that these layers probably form from the interaction of the brine drainage with the percolation of melt water from surface snow down into the ice and the rise of the oil from below. Finally in the summer, the oil on the surface leads to melt-pond formation. The solar energy absorbed by the oil on the surface of these melt ponds eventually causes the melt pond to melt through the ice, and the oil is again released into the ocean.

Download Full-text

Estimation of Level and Deformed First-Year Sea Ice Surface Roughness in the Canadian Arctic Archipelago from C- and L-Band Synthetic Aperture Radar

Canadian Journal of Remote Sensing ◽

10.1080/07038992.2019.1647102 ◽

2019 ◽

Vol 45 (3-4) ◽

pp. 457-475 ◽

Cited By ~ 2

Author(s):

Silvie Marie Cafarella ◽

Randall Scharien ◽

Torsten Geldsetzer ◽

Stephen Howell ◽

Christian Haas ◽

...

Keyword(s):

Surface Roughness ◽

Sea Ice ◽

Synthetic Aperture Radar ◽

Canadian Arctic ◽

Synthetic Aperture ◽

First Year ◽

Canadian Arctic Archipelago ◽

Ice Surface ◽

L Band ◽

Ice Surface Roughness

Download Full-text

Predicting Melt Pond Fraction on Landfast Snow Covered First Year Sea Ice from Winter C-Band SAR Backscatter Utilizing Linear, Polarimetric and Texture Parameters

Remote Sensing ◽

10.3390/rs10101603 ◽

2018 ◽

Vol 10 (10) ◽

pp. 1603 ◽

Cited By ~ 1

Author(s):

Saroat Ramjan ◽

Torsten Geldsetzer ◽

Randall Scharien ◽

John Yackel

Keyword(s):

Sea Ice ◽

Regression Models ◽

Incidence Angle ◽

Early Summer ◽

Aerial Photographs ◽

Late Winter ◽

First Year ◽

Melt Pond ◽

Texture Parameters ◽

Snow Thickness

Early-summer melt pond fraction is predicted using late-winter C-band backscatter of snow-covered first-year sea ice. Aerial photographs were acquired during an early-summer 2012 field campaign in Resolute Passage, Nunavut, Canada, on smooth first-year sea ice to estimate the melt pond fraction. RADARSAT-2 Synthetic Aperture Radar (SAR) data were acquired over the study area in late winter prior to melt onset. Correlations between the melt pond fractions and late-winter linear and polarimetric SAR parameters and texture measures derived from the SAR parameters are utilized to develop multivariate regression models that predict melt pond fractions. The results demonstrate substantial capability of the regression models to predict melt pond fractions for all SAR incidence angle ranges. The combination of the most significant linear, polarimetric and texture parameters provide the best model at far-range incidence angles, with an R 2 of 0.62 and a pond fraction RMSE of 0.09. Near- and mid- range incidence angle models provide R 2 values of 0.57 and 0.61, respectively, with an RMSE of 0.11. The strength of the regression models improves when SAR parameters are combined with texture parameters. These predictions also serve as a proxy to estimate snow thickness distributions during late winter as higher pond fractions evolve from thinner snow cover.

Download Full-text

Snow Thickness Estimation on First-Year Sea Ice from Late Winter Spaceborne Scatterometer Backscatter Variance

Remote Sensing ◽

10.3390/rs11040417 ◽

2019 ◽

Vol 11 (4) ◽

pp. 417 ◽

Cited By ~ 5

Author(s):

John Yackel ◽

Torsten Geldsetzer ◽

Mallik Mahmud ◽

Vishnu Nandan ◽

Stephen Howell ◽

...

Keyword(s):

Sea Ice ◽

Snow Cover ◽

Winter Season ◽

Late Winter ◽

First Year ◽

Snow Layer ◽

Independent Case ◽

Brine Volume ◽

Snow Thickness

Ku- and C-band spaceborne scatterometer sigma nought (σ°) backscatter data of snow covered landfast first-year sea ice from the Canadian Arctic Archipelago are acquired during the winter season with coincident in situ snow-thickness observations. Our objective is to describe a methodological framework for estimating relative snow thickness on first-year sea ice based on the variance in σ° from daily time series ASCAT and QuikSCAT scatterometer measurements during the late winter season prior to melt onset. We first describe our theoretical basis for this approach, including assumptions and conditions under which the method is ideally suited and then present observational evidence from four independent case studies to support our hypothesis. Results suggest that the approach can provide a relative measure of snow thickness prior to σ° detected melt onset at both Ku- and C-band frequencies. We observe that, during the late winter season, a thinner snow cover displays a larger variance in daily σ° compared to a thicker snow cover on first-year sea ice. This is because for a given increase in air temperature, a thinner snow cover manifests a larger increase in basal snow layer brine volume owing to its higher thermal conductivity, a larger increase in the dielectric constant and a larger increase in σ° at both Ku- and C bands. The approach does not apply when snow thickness distributions on first-year sea ice being compared are statistically similar, indicating that similar late winter σ° variances likely indicate regions of similar snow thickness.

Download Full-text

An intercomparison between AMSR-E snow-depth and satellite C- and Ku-band radar backscatter data for Antarctic sea ice

Annals of Glaciology ◽

10.3189/172756411795931750 ◽

2011 ◽

Vol 52 (57) ◽

pp. 279-290 ◽

Cited By ~ 14

Author(s):

Stefan Kern ◽

Burcu Ozsoy-Cicek ◽

Sascha Willmes ◽

Marcel Nicolaus ◽

Christian Haas ◽

...

Keyword(s):

Sea Ice ◽

Snow Depth ◽

Weddell Sea ◽

Late Winter ◽

First Year ◽

Radar Backscatter ◽

Antarctic Sea Ice ◽

Ridged Ice ◽

Ice Fraction ◽

Ku Band

AbstractAdvanced Microwave Scanning Radiometer (AMSR-E) snow-depth data for Antarctic sea ice are compared with ship-based visual observations of snow depth, ice type and ridged-ice fraction, and with satellite C-band and Ku-band radar backscatter observations for two ship cruises into the Weddell Sea (ISPOL 2004–05,WWOS 2006) and one cruise into the Bellingshausen Sea (SIMBA 2007) during late winter/spring. Most (>75%) AMSR-E and ship-based snow-depth observations agree within 0.2 m during WWOS and SIMBA. Remaining observations indicate substantial underestimations of snow depths by AMSR-E data. These underestimations tend to increase with the ridged-ice fraction for WWOS and SIMBA. In areas with large snow depths, a combination of relatively stable low C-band radar backscatter and variable Ku-band radar backscatter is associated with undeformed first-year ice and may indicate snow metamorphism at this time of year during SIMBA. In areas with small snow depths, a combination of relatively stable low Ku-band radar backscatter, high C-band radar backscatter and low C-band radar backscatter standard deviations is associated with rough first-year ice during SIMBA. This information can help to better understand causes of the observed AMSR-E snow-depth bias during late-winter/spring conditions with decreasing average snow depth and to delineate areas where this bias occurs.

Download Full-text

A Subice Suction Corer for Sampling Epontic Ice Algae

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f88-067 ◽

1988 ◽

Vol 45 (3) ◽

pp. 562-568 ◽

Cited By ~ 18

Author(s):

Harold E. Welch ◽

Martin A. Bergmann ◽

John K. Jorgenson ◽

William Burton

Keyword(s):

Sea Ice ◽

Quantitative Assessment ◽

Early Spring ◽

Late Winter ◽

First Year ◽

Ice Algae ◽

Sources Of Error

Standard SIPRE coring was compared with a new Subice Suction Corer and cores taken by diver for the quantitative assessment of epontic (subice) algae on first-year congelation sea ice at Resolute, N.W.T., Canada (≈75°N). The diver cores were probably most accurate but were slow and costly. SIPRE coring was as good as other techniques in late winter and early spring but gave progressively poorer (under) estimates as the season progressed, with up to 90% of the ice algae being lost from SIPRE cores by June. The Subice Suction Corer was fast, easy to operate, cheap, and gave results comparable with samples obtained by diving. Sources of error are discussed.

Download Full-text