Biomarker distributions in surface sediments of the northern Barents Sea: a basis for accurate palaeo sea-ice reconstructions

2020 ◽  
Author(s):  
Anna J. Pienkowski ◽  
Katrine Husum ◽  
Simon Belt ◽  
Lukas Smik
Keyword(s):  
Sea Ice ◽  
Surface Sediments ◽  
Barents Sea ◽  
General Pattern ◽  
Environmental Parameters ◽  
Sea Ice Concentration ◽  
Marine Surface ◽  
Ice Edge ◽  
Spring Sea Ice ◽  
Sea Ice Edge

<p>An understanding of modern sea-ice proxy distributions relative to measured environmental parameters underpins accurate palaeo reconstructions necessary for correct future projections. We here present new data on highly-branched isoprenoid (HBI) lipid biomarkers produced by sea-ice diatoms (IP<sub>25</sub>, IPSO<sub>25</sub>) and phytoplankton (HBI III, HBI IV) in marine surface sediments taken in a south-north transect east of Svalbard as part of the Nansen Legacy project. Collectively, these biomarkers can be used to reconstruct seasonal spring sea-ice (SpSIC) and the seasonal sea-ice edge. Eight sites at ~78-83°N were sampled by multicorer. All cores contain abundant biomarkers, except the northernmost station. Biomarker-based SpSIC shows a general south-north increase, mimicking observational sea-ice concentration satellite-based means (1988-2017). The HBI T<sub>25</sub> index suggests ice edge phytoplankton blooms at southern stations, agreeing with the general pattern of increased phytoplankton HBIs previously reported from the eastern Barents Sea. As a next step, these new biomarker findings will be used to reconstruct longer-term (Holocene) variability in sea-ice in this region. </p>

scholarly journals The effect of changing sea ice on the vulnerability of Arctic coasts

2014 ◽  
Vol 8 (3) ◽  
pp. 2277-2329 ◽  
Author(s):  
K. R. Barnhart ◽  
I. Overeem ◽  
R. S. Anderson
Keyword(s):  
Sea Ice ◽  
Water Level ◽  
Coastal Erosion ◽  
Extreme Values ◽  
Open Water ◽  
Water Levels ◽  
The Arctic ◽  
Sea Ice Concentration ◽  
Ice Edge ◽  
Sea Ice Edge

Abstract. Shorefast sea ice prevents the interaction of the land and the ocean in the Arctic winter and influences this interaction in the summer by governing the fetch. In many parts of the Arctic the sea-ice-free season is increasing in duration, and the summertime sea ice extents are decreasing. Sea ice provides a first order control on the vulnerability of Arctic coasts to erosion, inundation, and damage to settlements and infrastructure. We ask how the changing sea ice cover has influenced coastal erosion over the satellite record. First, we present a pan-Arctic analysis of satellite-based sea ice concentration specifically along the Arctic coasts. The median length of the 2012 open water season in comparison to 1979 expanded by between 1.5 and 3-fold by Arctic sea sector which allows for open water during the stormy Arctic fall. Second, we present a case study of Drew Point, Alaska, a site on the Beaufort Sea characterized by ice-rich permafrost and rapid coastal erosion rates where both the duration of the sea ice free season and distance to the sea ice edge, particularly towards the northwest, has increased. At Drew Point, winds from the northwest result in increased water levels at the coast and control the process of submarine notch incision, the rate-limiting step of coastal retreat. When open water conditions exist, the distance to the sea ice edge exerts control on the water level and wave field through its control on fetch. We find that the extreme values of water level set-up have increased, consistent with increasing fetch.

Sensitivity of Atmosphere-Ocean Interactions during Cold Air Outbreaks to Characteristics of the Sea-Ice Edge

2020 ◽  
Author(s):  
Thomas Spengler ◽  
Clemens Spensberger
Keyword(s):  
Sea Ice ◽  
Heat Fluxes ◽  
Model Resolution ◽  
Layer Model ◽  
Sea Ice Concentration ◽  
Cold Air ◽  
Ice Concentration ◽  
Ice Edge ◽  
Sea Ice Edge ◽  
Cold Air Outbreaks

<p>Cold air outbreaks play a crucial role in the air-sea heat exchange in the higher latitudes. However, we still lack some basic understanding about the sensitivities of these phenomena to latent heating and the role of coupling to the ocean. Despite increasing model resolution, reliable forecasts of these events remain a challenge because of the vast range of scales and physical processes involved. To further explore these sensitivities and dependence on model representation, we couple a moist convective atmospheric boundary layer model with an ocean mixed layer model to investigate the response of moist convection as well as ocean mixing during cold air outbreaks. In addition, we perform sensitivity experiments based on the PolarWRF model in an idealised configuration to represent cold air outbreaks.</p><p>Varying sea ice concentration and resolution alters the distribution and intensity of the air-sea heat exchange with ramifications for mixed layer depths in both the atmosphere and ocean. Furthermore, integrated and local sensible and latent heat fluxes depend on the model resolution as well as the distribution of the sea-ice concentration in the marginal ice zone. While surface sensible heat fluxes appear to be rather consistent across different model resolutions, surface latent heat fluxes respond to the organisation of convection at higher resolutions, a feature that is absent for coarser model grids. Different geometries replacing a straight sea-ice edge with various simple geometrical shapes are also tested. Our results have implications for numerical weather prediction and climate models, in particular regarding model resolution and the degree of coupling for the representation of air-sea interaction during cold air outbreaks.</p>

scholarly journals Changes in Barents Sea ice Edge Positions in the Last 440 years: A Review of Possible Driving Forces

2020 ◽  
Vol 10 (02) ◽  
pp. 97-164 ◽  
Author(s):  
Nils-Axel Mörner ◽  
Jan-Erik Solheim ◽  
Ole Humlum ◽  
Stig Falk-Petersen
Keyword(s):  
Sea Ice ◽  
Barents Sea ◽  
Driving Forces ◽  
Ice Edge ◽  
Sea Ice Edge

scholarly journals Changes in Barents Sea Ice Edge Positions in the Last 442 Years. Part 2: Sun, Moon and Planets

2021 ◽  
Vol 11 (02) ◽  
pp. 279-341
Author(s):  
Jan-Erik Solheim ◽  
Stig Falk-Petersen ◽  
Ole Humlum ◽  
Nils-Axel Mörner
Keyword(s):  
Sea Ice ◽  
Barents Sea ◽  
Ice Edge ◽  
Sea Ice Edge

Sea Ice Distribution in the Barents Sea

2016 ◽  
Author(s):  
Sindre M. Fritzner ◽  
Trond Sagerup
Keyword(s):  
Sea Ice ◽  
Normal Distribution ◽  
Barents Sea ◽  
Extreme Value Distribution ◽  
Extreme Value ◽  
Distribution Functions ◽  
Value Distribution ◽  
The Barents Sea ◽  
Ice Edge ◽  
Sea Ice Edge

This paper provides a statistical description of the sea ice occurrence in the Barents Sea, using yearly maximum sea ice data for the last 36 years from the European Centre for Medium-Range Weather Forecasts (ECMWF). A set of four distribution functions have been estimated with the maximum likelihood method. The distribution functions used were Extreme Value distribution, Gumbel distribution, Normal distribution and kernel density estimation. The normal distribution was found to fit the data best and provide the most likely result. Our results verify dependency of the North Atlantic current on the sea ice edge. Warm water northwards prevents the ice from extending south; this makes the extreme value distribution unlikely since this will prevent long tailed distributions. The results for sea ice occurrence are compared to the boundaries given in the proposed revision to NORSOK N-003. These boundaries were found to be too simplistic and not necessarily conservative. Here we have proposed new and more accurate boundaries for the sea ice occurrence. We have found trends indicating northwards movement of the sea ice edge in the Norwegian Sea and eastern parts of the Barents Sea. These trends are mostly due to less ice in the last ten years and not trends for the whole period. In the south-western parts of the Barents Sea where oil and gas operations are imminent no trends have been discovered. The lack of trend is related to the islands in the western Barents Sea.

Use of C-Band Scatterometer for Sea Ice Edge Identification

2012 ◽  
Vol 50 (7) ◽  
pp. 2669-2677 ◽  
Author(s):  
Lars-Anders Breivik ◽  
Steinar Eastwood ◽  
Thomas Lavergne
Keyword(s):  
Sea Ice ◽  
Ice Edge ◽  
Sea Ice Edge

On the Bering Sea ice edge front

1985 ◽  
Vol 90 (C2) ◽  
pp. 3185 ◽  
Author(s):  
Robin D. Muench ◽  
James D. Schumacher
Keyword(s):  
Sea Ice ◽  
Bering Sea ◽  
Ice Edge ◽  
Sea Ice Edge ◽  
The Bering Sea
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