scholarly journals Sea ice cover in Isfjorden and Hornsund 2000–2014 by using remote sensing

2015 ◽  
Vol 9 (4) ◽  
pp. 4043-4066
Author(s):  
S. Muckenhuber ◽  
F. Nilsen ◽  
A. Korosov ◽  
S. Sandven
Keyword(s):  
Sea Ice ◽  
Open Water ◽  
Ice Cover ◽  
Ice Coverage ◽  
Time Period ◽  
Ice Drift ◽  
Before And After ◽  
Ice Conditions ◽  
Fast Ice ◽  
The Mean

Abstract. A satellite database including 16 555 satellite images and ice charts displaying the area of Isfjorden, Hornsund and the Svalbard region has been established with focus on the time period 2000–2014. 3319 manual interpretations of sea ice conditions have been conducted, resulting in two time series dividing the area of Isfjorden and Hornsund into "Fast ice", "Drift ice" and open "Water". The maximum fast ice coverage of Isfjorden is > 40 % in the periods 2000–2005 and 2009–2011 and stays < 30 % in 2006–2008 and 2012–2014. Fast ice cover in Hornsund reaches > 40 % in all considered years, except for 2012 and 2014, where the maximum stays < 20 %. The mean seasonal cycles of fast ice in Isfjorden and Hornsund show monthly averaged values of less than 1 % between July and November and maxima in March (Isfjorden, 35.7 %) and April (Hornsund, 42.1 %) respectively. A significant reduction of the monthly averaged fast ice coverage is found when comparing the time periods 2000–2005 and 2006–2014. The seasonal maximum decreases from 57.5 to 23.2 % in Isfjorden and from 52.6 to 35.2 % in Hornsund. A new concept, called "days of fast ice coverage" (DFI), is introduced for quantification of the interannual variation of fast ice cover, allowing for comparison between different fjords and winter seasons. Considering the time period from 1 March until end of sea ice season, the mean DFI values for 2000–2014 are 33.1 ± 18.2 DFI (Isfjorden) and 42.9 ± 18.2 DFI (Hornsund). A distinct shift to lower DFI values is observed in 2006. Calculating a mean before and after 2006 yields a decrease from 50 to 22 DFI for Isfjorden and from 56 to 34 DFI for Hornsund.

scholarly journals Sea ice cover in Isfjorden and Hornsund, Svalbard (2000–2014) from remote sensing data

2016 ◽  
Vol 10 (1) ◽  
pp. 149-158 ◽  
Author(s):  
S. Muckenhuber ◽  
F. Nilsen ◽  
A. Korosov ◽  
S. Sandven
Keyword(s):  
Remote Sensing ◽  
Time Series ◽  
Sea Ice ◽  
Heat Content ◽  
Ice Cover ◽  
Climate Effect ◽  
Ice Coverage ◽  
Time Period ◽  
Fast Ice ◽  
The Mean

Abstract. A satellite database including 16 555 satellite images and ice charts displaying the area of Isfjorden, Hornsund, and the Svalbard region has been established with focus on the time period 2000–2014. 3319 manual interpretations of sea ice conditions have been conducted, resulting in two time series dividing the area of Isfjorden and Hornsund into "fast ice" (sea ice attached to the coastline), "drift ice", and "open water". The maximum fast ice coverage of Isfjorden is  >  40 % in the periods 2000–2005 and 2009–2011 and stays  <  30 % in 2006–2008 and 2012–2014. Fast ice cover in Hornsund reaches  >  40 % in all considered years, except for 2012 and 2014, where the maximum stays  <  20 %. The mean seasonal cycles of fast ice in Isfjorden and Hornsund show monthly averaged values of less than 1 % between July and November and maxima in March (Isfjorden, 35.7 %) and April (Hornsund, 42.1 %), respectively. A significant reduction of the monthly averaged fast ice coverage is found when comparing the time periods 2000–2005 and 2006–2014. The seasonal maximum decreases from 57.5 to 23.2 % in Isfjorden and from 52.6 to 35.2 % in Hornsund. A new index, called "days of fast ice" (DFI), is introduced for quantification of the interannual variation of fast ice cover, allowing for comparison between different fjords and winter seasons. Considering the time period from 1 March until end of the sea ice season, the mean DFI values for 2000–2014 are 33.1 ± 18.2 DFI (Isfjorden) and 42.9 ± 18.2 DFI (Hornsund). A distinct shift to lower DFI values is observed in 2006. Calculating a mean before and after 2006 yields a decrease from 50 to 22 DFI for Isfjorden and from 56 to 34 DFI for Hornsund. Fast ice coverage generally correlates well with remote-sensing sea surface temperature and in situ air temperature. An increase of autumn ocean heat content is observed during the last few years when the DFI values decrease. The presented sea ice time series can be utilized for various climate effect studies linked to, e.g. glacier dynamics, ocean chemistry, and marine biology.

scholarly journals Multiproxy evidence of the Neoglacial expansion of Atlantic Water to eastern Svalbard: Does ancient environmental DNA complement sedimentary and microfossil records?

2019 ◽  
Author(s):  
Joanna Pawłowska ◽  
Magdalena Łącka ◽  
Małgorzata Kucharska ◽  
Jan Pawlowski ◽  
Marek Zajączkowski
Keyword(s):  
Sea Ice ◽  
Dna Sequences ◽  
Environmental Changes ◽  
Environmental Dna ◽  
Open Water ◽  
Ice Cover ◽  
Atlantic Water ◽  
Ice Coverage ◽  
Ice Conditions ◽  
Multiproxy Approach

Abstract. The main goal of this study was to reconstruct the paleoceanographic development of Storfjorden during the Neoglacial (~ 4 cal ka BP). A multiproxy approach was applied to provide evidence for interactions between the inflow of Atlantic Water (AW) and sea-ice coverage, which are the major drivers of environmental changes in Storfjorden. The sedimentary and microfossil records indicate that a major reorganization of oceanographic conditions in Storfjorden occurred at ~ 2.7 cal ka BP. A general cooling and the less pronounced presence of AW in Storfjorden during the early phase of the Neoglacial are prerequisite conditions for the formation of an extensive sea-ice cover. The period after ~ 2.7 cal ka BP was characterized by alternating short-term cooling and warming intervals. Warming was associated with pulsed inflows of AW and sea-ice melting that stimulated phytoplankton blooms and organic matter supply to the bottom. The cold phases were characterized by heavy and densely packed sea ice resulting in a decrease in productivity. The ancient environmental DNA (aDNA) records of foraminifera and diatoms reveal the timing of the major pulses of AW (~ 2.3 and ~ 1.7 cal ka BP) and the variation in sea-ice cover. The AW inflow was marked by an increase in the percentage of DNA sequences of monothalamous foraminifera associated with the presence of fresh phytodetritus, while cold and less productive intervals were marked by an increased proportion of monothalamous taxa known only from environmental sequencing. The diatom aDNA record indicates that primary production was continuous during the Neoglacial regardless of sea-ice conditions. However, the colder periods were characterized by the presence of diatom taxa associated with sea ice, whereas the present-day diatom assemblage is dominated by open-water taxa.

scholarly journals Multiproxy evidence of the Neoglacial expansion of Atlantic Water to eastern Svalbard

2020 ◽  
Vol 16 (2) ◽  
pp. 487-501 ◽  
Author(s):  
Joanna Pawłowska ◽  
Magdalena Łącka ◽  
Małgorzata Kucharska ◽  
Jan Pawlowski ◽  
Marek Zajączkowski
Keyword(s):  
Sea Ice ◽  
Dna Sequences ◽  
Environmental Changes ◽  
Environmental Dna ◽  
Open Water ◽  
Ice Cover ◽  
Atlantic Water ◽  
Arctic Water ◽  
Ice Coverage ◽  
Ice Conditions

Abstract. The main goal of this study is to reconstruct the paleoceanographic development of Storfjorden during the Neoglacial (∼4 cal ka BP). Storfjorden is one of the most important brine factories in the European Arctic and is responsible for deepwater production. Moreover, it is a climate-sensitive area influenced by two contrasting water masses: warm and saline Atlantic Water (AW) and cold and fresh Arctic Water (ArW). Herein, a multiproxy approach was applied to provide evidence for existing interactions between the inflow of AW and sea ice coverage, which are the major drivers of environmental changes in Storfjorden. The sedimentary and microfossil records indicate that a major reorganization of oceanographic conditions in Storfjorden occurred at ∼2.7 cal ka BP. The cold conditions and the less pronounced presence of AW in Storfjorden during the early phase of the Neoglacial were the prerequisite conditions for the formation of extensive sea ice cover. The period after ∼2.7 cal ka BP was characterized by alternating short-term cooling and warming intervals. Warming was associated with pulsed inflows of AW and sea ice melting that stimulated phytoplankton blooms and organic matter supply to the bottom. The cold phases were characterized by heavy and densely packed sea ice, resulting in decreased productivity. The ancient environmental DNA (aDNA) records of foraminifera and diatoms support the occurrence of the major pulses of AW (∼2.3 and ∼1.7 cal ka BP) and the variations in sea ice cover. The episodes of enhanced AW inflow were marked by an increase in the percentage of DNA sequences of monothalamous foraminifera associated with the presence of fresh phytodetritus. Cold and less productive intervals were marked by an increased proportion of monothalamous taxa known only from environmental sequencing. The diatom aDNA record indicates that primary production was continuous during the Neoglacial, regardless of the sea ice conditions. However, the colder periods were characterized by the presence of diatom taxa associated with sea ice, whereas the present-day diatom assemblage is dominated by open-water taxa.

The Effect of Protracted Spring Thaws on Ice Conditions in Hudson Bay *

1952 ◽  
Vol 33 (3) ◽  
pp. 101-106 ◽  
Author(s):  
G. A. Mackay
Keyword(s):  
Open Water ◽  
Weather Conditions ◽  
Ice Cover ◽  
Hudson Bay ◽  
Synoptic Weather ◽  
Ice Conditions ◽  
The Mean ◽  
Abnormal Weather

The extent of ice cover in Hudson Bay was investigated during the Spring of 1948 by the RCAF and interested governmental departments. A series of reconnaissance flights over the Bay in March and April disclosed that it was virtually ice-bound from shore to shore. Large areas of open water were observed during the period May 3rd to May 6th. An inspection of the synoptic weather charts disclosed that weather conditions over the Bay both prior to and during this period were abnormal. This immediately suggests that the ice conditions observed might not be representative. For an appraisal of the observations it is necessary to determine the effects of the abnormal weather on the ice. The observed ice conditions are mentioned and the causes of open water areas briefly discussed. The severity of the winter at Churchill was investigated to determine the normalcy of the ice development. A protracted thaw over the eastern parts of Hudson Bay is disclosed by reference to the weather charts. The correlation between the mean monthly temperatures for the spring months and the date of ice clearance at Churchill Harbour is then investigated to determine the effects of a protracted thaw on the ice.

Landfast ice zoning from SAR imagery

2020 ◽  
Author(s):  
Valeria Selyuzhenok ◽  
Denis Demchev ◽  
Thomas Krumpen
Keyword(s):  
Time Series ◽  
Sea Ice ◽  
Ice Cover ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Ice Drift ◽  
Landfast Ice ◽  
Sea Ice Drift ◽  
Ice Conditions ◽  
Sar Imagery

&lt;p&gt;Landfast sea ice is a dominant sea ice feature of the Arctic coastal region. As a part of Arctic sea ice cover, landfast ice is an important part of coastal ecosystem, it provides functions as a climate regulator and platform for human activity. Recent changes in sea ice conditions in the Arctic have also affected landfast ice regime. At the same time, industrial interest in the Arctic shelf seas continue to increase. Knowledge on local landfast ice conditions are required to ensure safety of on ice operations and accurate forecasting.&amp;#160; In order to obtain a comprehensive information on landfast ice state we use a time series of wide swath SAR imagery.&amp;#160; An automatic sea ice tracking algorithm was applied to the sequential SAR images during the development stage of landfast ice cover. The analysis of resultant time series of sea ice drift allows to classify homogeneous sea ice drift fields and timing of their attachment to the landfast ice. In addition, the drift data allows to locate areas of formation of grounded sea ice accumulation called stamukha. This information &amp;#1089;an be useful for local landfast ice stability assessment. The study is supported by the Russian Foundation for Basic Research (RFBR) grant 19-35-60033.&lt;/p&gt;

scholarly journals Automated Underway Eddy Covariance System for Air–Sea Momentum, Heat, and CO2 Fluxes in the Southern Ocean

2016 ◽  
Vol 33 (4) ◽  
pp. 635-652 ◽  
Author(s):  
Brian J. Butterworth ◽  
Scott D. Miller
Keyword(s):  
Southern Ocean ◽  
Sea Ice ◽  
Eddy Covariance ◽  
Open Water ◽  
Ice Cover ◽  
Published Data ◽  
Flow Distortion ◽  
Ice Conditions ◽  
Antarctic Research ◽  
Processing Techniques

AbstractA ruggedized closed-path eddy covariance (EC) system was designed for unattended direct measurements of air–sea momentum, heat, and CO2 flux, and was deployed on the Research Vessel Icebreaker (RV/IB) Nathaniel B. Palmer (NBP), an Antarctic research and supply vessel. The system operated for nine cruises during 18 months from January 2013 to June 2014 in the Southern Ocean and coastal Antarctica, sampling a wide variety of wind, wave, biological productivity, and ice conditions. The methods are described and the results are shown for two cruises chosen for their latitudinal range, inclusion of both open water and sea ice cover, and relatively large air–water CO2 concentration differences (ΔpCO2). Ship flow distortion was addressed by comparing mean winds, fluxes, and cospectra from an array of 3D anemometers at the NBP bow, comparing measured fluxes with bulk formulas, and implementing and evaluating several recently published data processing techniques. Quality-controlled momentum, heat, and CO2 flux data were obtained for 25% of the periods when NBP was at sea, with most (86%) of the rejected periods due to wind directions relative to the ship >±30° from the bow. In contrast to previous studies, no bias was apparent in measured CO2 fluxes for low |ΔpCO2|. The relationship between momentum flux and wind speed showed a clear dependence on the degree of sea ice cover, a result facilitated by the geographical coverage possible with a ship-based approach. These results indicate that ship-based unattended EC in high latitudes is feasible, and recommendations for deployments of underway systems in such environments are provided.

scholarly journals Sea ice and the stability of north and northeast Greenland floating glaciers

2001 ◽  
Vol 33 ◽  
pp. 474-480 ◽  
Author(s):  
Niels Reeh ◽  
Henrik Højmark Thomsen ◽  
Anthony K. Higgins ◽  
Anker Weidick
Keyword(s):  
Sea Ice ◽  
Ice Cover ◽  
Aerial Photographs ◽  
The Arctic ◽  
The North ◽  
Glacier Ice ◽  
Ice Conditions ◽  
Fast Ice ◽  
Break Up ◽  
The Stability

AbstractThe interaction between sea ice and glaciers has been studied for the floating tongue of Nioghalvfjerdsfjorden glacier, northeast Greenland (79°30’N, 22° W). Information from glacial geological studies, expedition reports, aerial photographs and satellite imagery is used to document the glacier front position and fast-ice conditions on millennial to decadal time-scales. The studies indicate that the stability of the floating glacier margin is dependent on the presence of a protecting fast-ice cover in front of the glacier. In periods with a permanent fast-ice cover, no calving occurs, but after fast-ice break-up the glacier responds with a large calving activity, whereby several years of accumulated glacier-ice flux suddenly breaks away. Climate-induced changes of sea-ice conditions in the Arctic Ocean with seasonal break-up of the near-shore fast ice could lead to disintegration of the floating glaciers. The present dominant mass loss by bottom melting would then to a large extent be taken over by grounding-line calving of icebergs. The local influx of fresh water from the north Greenland glaciers to the sea would be reduced and the local iceberg production would increase.

Arctic sea ice extent and thickness

1995 ◽  
Vol 352 (1699) ◽  
pp. 301-319 ◽  
Keyword(s):  
Sea Ice ◽  
Open Water ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Ice Thickness ◽  
Sea Ice Extent ◽  
Arctic Sea ◽  
Ice Conditions ◽  
Fast Ice ◽  
Arctic Sea Ice Extent

Current knowledge on Arctic sea ice extent and thickness variability is reviewed, and we examine whether measurements to date provide evidence for the impact of climate change. The total Arctic ice extent has shown a small but significant reduction of (2.1 ± 0.9)% during the period 1978-87, after apparently increasing from a lower level in the early 1970s. However, open water within the pack ice limit has also diminished, so that the reduction of sea ice area is only (1.8 ± 1.2)%. This stability conceals large interannual variations and trends in individual regions of the Arctic Ocean and sub-Arctic seas, which are out of phase with one another and so have little net impact on the overall hemispheric ice extent. The maximum annual global extent (occurring during the Antarctic winter) shows a more significant decrease of 5% during 1972-87. Ice thickness distribution has been measured by submarine sonar profiling, moored upward sonars, airborne laser prohlometry, airborne electromagnetic techniques and drilling. Promising new techniques include: sonar mounted on an AUV or neutrally buoyant float; acoustic tomography or thermometry; and inference from a combination of microwave sensors. In relation to climate change, the most useful measurement has been repeated submarine sonar profiling under identical parts of the Arctic, which offers some evidence of a decline in mean ice thickness in the 1980s compared to the 1970s. The link between mean ice thickness and climatic warming is complex because of the effects of dynamics and deformation. Only fast ice responds primarily to air temperature changes and one can predict thinning of fast ice and extension of the open water season in fast ice areas. Another region of increasingly mild ice conditions is the central Greenland Sea where winter thermohaline convection is triggered by cyclic growth and melt of local young ice. In recent years convection to the bottom has slowed or ceased, possibly related to moderation of ice conditions.

scholarly journals Brief communication: The anomalous winter 2019 sea ice conditions in McMurdo Sound, Antarctica

2021 ◽  
Author(s):  
Greg H. Leonard ◽  
Kate E. Turner ◽  
Maren E. Richter ◽  
Maddy S. Whittaker ◽  
Inga J. Smith
Keyword(s):  
Sea Ice ◽  
Strong Correlation ◽  
Ross Sea ◽  
Ice Cover ◽  
Katabatic Wind ◽  
Mcmurdo Sound ◽  
Southerly Wind ◽  
Ice Conditions ◽  
Fast Ice ◽  
Wind Events

Abstract. McMurdo Sound sea ice can generally be partitioned into two regimes: (1) a stable fast-ice cover, forming south of approximately 77.6° S around March/April, then breaking out the following January/February; and, (2) a more dynamic region north of 77.6° S that the McMurdo Sound and Ross Sea polynyas regularly impact. In 2019, a stable fast-ice cover formed unusually late due to repeated breakout events. We analyse the 2019 sea-ice conditions and relate them to southerly wind events using a Katabatic Wind Index (KWI). We find there is a strong correlation between breakout events and several unusually large KWI events.

scholarly journals Brief communication: The anomalous winter 2019 sea-ice conditions in McMurdo Sound, Antarctica

2021 ◽  
Vol 15 (10) ◽  
pp. 4999-5006
Author(s):  
Greg H. Leonard ◽  
Kate E. Turner ◽  
Maren E. Richter ◽  
Maddy S. Whittaker ◽  
Inga J. Smith
Keyword(s):  
Sea Ice ◽  
Strong Correlation ◽  
Ross Sea ◽  
Ice Cover ◽  
Mcmurdo Sound ◽  
Southerly Wind ◽  
Ice Conditions ◽  
Fast Ice ◽  
Wind Events ◽  
Storm Index

Abstract. McMurdo Sound sea ice can generally be partitioned into two regimes: (1) a stable fast-ice cover, forming south of approximately 77.6∘ S around March–April and then breaking out the following January–February, and (2) a more dynamic region north of 77.6∘ S that the McMurdo Sound and Ross Sea polynyas regularly impact. In 2019, a stable fast-ice cover formed unusually late due to repeated break-out events. We analyse the 2019 sea-ice conditions and relate them to a modified storm index (MSI), a proxy for southerly wind events. We find there is a strong correlation between the timing of break-out events and several unusually large MSI events.

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