scholarly journals Mapping pan-Arctic landfast sea ice stability using Sentinel-1 interferometry

2019 ◽  
Vol 13 (2) ◽  
pp. 557-577 ◽  
Author(s):  
Dyre O. Dammann ◽  
Leif E. B. Eriksson ◽  
Andrew R. Mahoney ◽  
Hajo Eicken ◽  
Franz J. Meyer
Keyword(s):  
Sea Ice ◽  
The Arctic ◽  
Sea Ice Extent ◽  
Marginal Seas ◽  
Nares Strait ◽  
Novel Approach ◽  
Landfast Ice ◽  
Landfast Sea Ice ◽  
Fringe Patterns ◽  
The Stability

Abstract. Arctic landfast sea ice has undergone substantial changes in recent decades, affecting ice stability and including potential impacts on ice travel by coastal populations and on industry ice roads. We present a novel approach for evaluating landfast sea ice stability on a pan-Arctic scale using Synthetic Aperture Radar Interferometry (InSAR). Using Sentinel-1 images from spring 2017, we discriminate between bottomfast, stabilized, and nonstabilized landfast ice over the main marginal seas of the Arctic Ocean (Beaufort, Chukchi, East Siberian, Laptev, and Kara seas). This approach draws on the evaluation of relative changes in interferometric fringe patterns. This first comprehensive assessment of Arctic bottomfast sea ice extent has revealed that most of the bottomfast sea ice is situated around river mouths and coastal shallows. The Laptev and East Siberian seas dominate the aerial extent, covering roughly 4100 and 5100 km2, respectively. These seas also contain the largest extent of stabilized and nonstabilized landfast ice, but are subject to the largest uncertainties surrounding the mapping scheme. Even so, we demonstrate the potential for using InSAR for assessing the stability of landfast ice in several key regions around the Arctic, providing a new understanding of how stability may vary between regions. InSAR-derived stability may serve for strategic planning and tactical decision support for different uses of coastal ice. In a case study of the Nares Strait, we demonstrate that interferograms may reveal early-warning signals for the breakup of stationary sea ice.

scholarly journals Landfast sea ice stability – mapping pan-Arctic ice regimes with implications for ice use, subsea permafrost and marine habitats

2018 ◽  
Author(s):  
Dyre O. Dammann ◽  
Leif E. B. Eriksson ◽  
Andrew R. Mahoney ◽  
Hajo Eicken ◽  
Franz J. Meyer
Keyword(s):  
Sea Ice ◽  
Chukchi Sea ◽  
The Arctic ◽  
Small Scale ◽  
Sea Ice Extent ◽  
Support Tool ◽  
Marine Habitats ◽  
Landfast Ice ◽  
Landfast Sea Ice ◽  
Subsea Permafrost

Abstract. Arctic landfast sea ice has undergone substantial changes in recent decades affecting ice stability with potential impacts on ice travel by coastal populations and industry ice roads. The role of landfast ice as an important habitat has also evolved. We present a novel approach to evaluate sea ice stability on a pan-Arctic scale using Synthetic Aperture Radar Interferometry (InSAR). Using Sentinel-1 images from spring 2017, the approach discriminates between bottomfast, with critical relevance for subsea permafrost, as well as stabilized and non-stabilized floating landfast ice over the main marginal seas of the Arctic Ocean (Beaufort, Chukchi, East Siberian, Laptev and Kara Seas). The analysis draws on evaluation of small-scale lateral motion derived from relative changes in interferometric fringe patterns. This first comprehensive assessment of Arctic bottomfast sea ice extent revealed that by area most of the bottomfast sea ice is situated around river mouths and coastal shallows in the Laptev and East Siberian Seas, covering roughly 4.1 and 5.5 thousand km2 respectively. The fraction between non-stabilized and stabilized ice is lowest in the Beaufort at almost unity, and highest in the adjacent Chukchi Sea. Beyond the simple delineation of landfast ice zones, this work provides a new understanding of how stability regimes may vary between regions and over time. InSAR-derived stability data may serve as a strategic planning and tactical decision-support tool for different uses of coastal ice. Such information may also inform assessments of important sea ice habitats. In a case study, we examined an ice arch situated in Nares Strait demonstrating that interferograms may reveal early-warning signals for the break-up of stationary sea ice.

scholarly journals Ice-Associated Amphipods in a Pan-Arctic Scenario of Declining Sea Ice

2021 ◽  
Vol 8 ◽  
Author(s):  
Haakon Hop ◽  
Mikko Vihtakari ◽  
Bodil A. Bluhm ◽  
Malin Daase ◽  
Rolf Gradinger ◽  
...  
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Time Span ◽  
The Arctic ◽  
Ice Algae ◽  
Central Arctic Ocean ◽  
Ice Drift ◽  
Landfast Ice ◽  
Landfast Sea Ice ◽  
Important Habitat

Sea-ice macrofauna includes ice amphipods and benthic amphipods, as well as mysids. Amphipods are important components of the sympagic food web, which is fuelled by the production of ice algae. Data on the diversity of sea-ice biota have been collected as a part of scientific expeditions over decades, and here we present a pan-Arctic analysis of data on ice-associated amphipods and mysids assimilated over 35 years (1977–2012). The composition of species differed among the 13 locations around the Arctic, with main differences between basins and shelves and also between communities in drift ice and landfast sea ice. The sea ice has been dramatically reduced in extent and thickness during the recorded period, which has resulted in reduced abundance of ice amphipods as well as benthic amphipods in sea ice from the 1980’s to the 2010’s. The decline mainly involved Gammarus wilkitzkii coinciding with the disappearance of much of the multiyear sea ice, which is an important habitat for this long-lived species. Benthic amphipods were most diverse, and also showed a decline over the time-span. They had higher abundance closer to land where they are associated with landfast ice. However, they also occurred in the Central Arctic Ocean, which is likely related to the origin of sea ice over shallow water and subsequent transport in the transpolar ice drift. Recent sampling in the waters east and north of Svalbard has found continued presence of Apherusa glacialis, but almost no G. wilkitzkii. Monitoring by standardized methods is needed to detect further changes in community composition of ice amphipods related to reductions in sea-ice cover and ice type.

scholarly journals InSAR Monitoring of Arctic Landfast Sea Ice Deformation Using L-Band ALOS-2, C-Band Radarsat-2 and Sentinel-1

2021 ◽  
Vol 13 (22) ◽  
pp. 4570
Author(s):  
Zhaohua Chen ◽  
Benoit Montpetit ◽  
Sarah Banks ◽  
Lori White ◽  
Amir Behnamian ◽  
...  
Keyword(s):  
Time Series ◽  
Sea Ice ◽  
The Arctic ◽  
Process Time ◽  
Time Interval ◽  
L Band ◽  
Sar Imagery ◽  
Landfast Sea Ice ◽  
Small Baseline ◽  
The Stability

Arctic amplification is accelerating changes in sea ice regimes in the Canadian Arctic with later freeze-up and earlier melt events, adversely affecting Arctic wildlife and communities that depend on the stability of sea ice conditions. To monitor both the rate and impact of such change, there is a need to accurately measure sea ice deformation, an important component for understanding ice motion and polar climate. The objective of this study is to determine the spatial-temporal pattern of deformation over landfast ice in the Arctic using time series SAR imagery. We present Interferometric Synthetic Aperture Radar (InSAR) monitoring of Arctic landfast sea ice deformation using C-band Radarsat-2, Sentinel-1 and L-band ALOS-2 in this paper. The small baseline subset (SBAS) approach was explored to process time series observations for retrieval of temporal deformation changes along a line-of-sight direction (LOS) over the winter. It was found that temporal and spatial patterns of deformation observed from different sensors were generally consistent. Horizontal and vertical deformations were also retrieved by a multi-dimensional SBAS technique using both ascending and descending Sentinel-1 observations. Results showed a horizontal deformation in the range of -95-85 cm, and vertical deformation in the range of -41-63 cm in Cambridge Bay, Nunavut, Canada during February-April 2019. High coherence over ice from C-band was maintained over a shorter time interval of acquisitions than L-band due to temporal decorrelation.

scholarly journals The role of atmospheric circulation in the growth of sea-ice extent in marginal seas around the Arctic Ocean

2005 ◽  
Vol 42 ◽  
pp. 352-360 ◽  
Author(s):  
Kunio Rikiishi ◽  
Hideaki Ohtake ◽  
Yurika Katagiri
Keyword(s):  
Sea Ice ◽  
Negative Correlation ◽  
The Arctic ◽  
Aleutian Low ◽  
Sea Ice Extent ◽  
Ice Growth ◽  
Marginal Seas ◽  
The Arctic Ocean ◽  
Icelandic Low

AbstractSatellite data of weekly sea-ice extent and monthly means of objectively analyzed upper-air observation for the years 1978–95 are analyzed in order to investigate the role of atmospheric circulation in the growth of sea-ice extent in five marginal seas around the Arctic Ocean. It has been found that in all the regions the sea ice advances when a cold wind blows from the land (or from the Arctic ice field) to the region, whereas it hardly advances (or it retreats) when a warm wind blows over the region. Whether the wind is favorable or unfavorable for sea-ice growth depends on the position and intensity of the Icelandic low in the Atlantic sector and of the Aleutian low in the Pacific sector. This leads to a negative correlation in ice growth between the western region (Labrador or Okhotsk Sea) and the eastern region (Barents or Bering Sea). Significant correlations are also found across the continents, that is, positive correlations between the Barents Sea and the Sea of Okhotsk, and between the Labrador and Bering Seas. These teleconnections of ice growth can be explained by taking into account an observed negative correlation between the activities of the Icelandic low and Aleutian low.

scholarly journals Decline of sea-ice in the Greenland Sea intensifies extreme precipitation over Svalbard

2021 ◽  
Author(s):  
Malte Muller ◽  
Timo Kelder ◽  
Cyril Palerme
Keyword(s):  
Sea Ice ◽  
Extreme Precipitation ◽  
The Arctic ◽  
Climate Change Signal ◽  
Sea Ice Extent ◽  
Svalbard Archipelago ◽  
The North ◽  
Extreme Precipitation Events ◽  
Novel Approach ◽  
Precipitation Record

Extreme precipitation over the Svalbard Archipelago in the Arctic can have severe consequences for the ecosystem and society. In recent years several extreme precipitation events have been observed at Ny Ålesund, a weather station in the north-western part of the Svalbard Archipelago. The most recent observed events in the years 2012, 2016, and 2018 were the highest events in the entire precipitation record from 1974 till today. The key question of our study is whether those recently observed extremes are part of a climate change signal or are a random accumulation of extremes. With a novel approach based on a large ensemble of model simulations, we show that the likelihood of occurrence for extreme precipitation over Svalbard has increased over the last four decades. We find that the likelihood of occurrence is connected to the sea ice extent east of Greenland because the presence of sea ice shields the west coast of Svalbard from the incoming southerly moist air. Our analysis suggests, that in the future with a further decline of the sea ice coverage east of Greenland, the recently observed precipitation extremes will become even more frequent.

scholarly journals Sea Ice Concentration and Sea Ice Extent Mapping with L-Band Microwave Radiometry and GNSS-R Data from the FFSCat Mission Using Neural Networks

2021 ◽  
Vol 13 (6) ◽  
pp. 1139
Author(s):  
David Llaveria ◽  
Juan Francesc Munoz-Martin ◽  
Christoph Herbert ◽  
Miriam Pablos ◽  
Hyuk Park ◽  
...  
Keyword(s):  
Sea Ice ◽  
Microwave Radiometer ◽  
Cost Effective ◽  
The Arctic ◽  
Sea Ice Concentration ◽  
Sea Ice Extent ◽  
Neural Network Approach ◽  
Ice Concentration ◽  
L Band ◽  
Moderate Cost

CubeSat-based Earth Observation missions have emerged in recent times, achieving scientifically valuable data at a moderate cost. FSSCat is a two 6U CubeSats mission, winner of the ESA S3 challenge and overall winner of the 2017 Copernicus Masters Competition, that was launched in September 2020. The first satellite, 3Cat-5/A, carries the FMPL-2 instrument, an L-band microwave radiometer and a GNSS-Reflectometer. This work presents a neural network approach for retrieving sea ice concentration and sea ice extent maps on the Arctic and the Antarctic oceans using FMPL-2 data. The results from the first months of operations are presented and analyzed, and the quality of the retrieved maps is assessed by comparing them with other existing sea ice concentration maps. As compared to OSI SAF products, the overall accuracy for the sea ice extent maps is greater than 97% using MWR data, and up to 99% when using combined GNSS-R and MWR data. In the case of Sea ice concentration, the absolute errors are lower than 5%, with MWR and lower than 3% combining it with the GNSS-R. The total extent area computed using this methodology is close, with 2.5% difference, to those computed by other well consolidated algorithms, such as OSI SAF or NSIDC. The approach presented for estimating sea ice extent and concentration maps is a cost-effective alternative, and using a constellation of CubeSats, it can be further improved.

scholarly journals Arctic Sea Ice Retreat in 2007 Follows Thinning Trend

2009 ◽  
Vol 22 (1) ◽  
pp. 165-176 ◽  
Author(s):  
R. W. Lindsay ◽  
J. Zhang ◽  
A. Schweiger ◽  
M. Steele ◽  
H. Stern
Keyword(s):  
Sea Ice ◽  
Arctic Ocean ◽  
Ocean Model ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Ice Thickness ◽  
Sea Ice Extent ◽  
Pacific Side ◽  
Arctic Sea ◽  
The Arctic Ocean

Abstract The minimum of Arctic sea ice extent in the summer of 2007 was unprecedented in the historical record. A coupled ice–ocean model is used to determine the state of the ice and ocean over the past 29 yr to investigate the causes of this ice extent minimum within a historical perspective. It is found that even though the 2007 ice extent was strongly anomalous, the loss in total ice mass was not. Rather, the 2007 ice mass loss is largely consistent with a steady decrease in ice thickness that began in 1987. Since then, the simulated mean September ice thickness within the Arctic Ocean has declined from 3.7 to 2.6 m at a rate of −0.57 m decade−1. Both the area coverage of thin ice at the beginning of the melt season and the total volume of ice lost in the summer have been steadily increasing. The combined impact of these two trends caused a large reduction in the September mean ice concentration in the Arctic Ocean. This created conditions during the summer of 2007 that allowed persistent winds to push the remaining ice from the Pacific side to the Atlantic side of the basin and more than usual into the Greenland Sea. This exposed large areas of open water, resulting in the record ice extent anomaly.

scholarly journals Sea-ice induced growth decline in Arctic shrubs

2017 ◽  
Vol 13 (8) ◽  
pp. 20170122 ◽  
Author(s):  
Mads Forchhammer
Keyword(s):  
Sea Ice ◽  
Ring Width ◽  
Plant Productivity ◽  
Climatic Conditions ◽  
Arctic Sea Ice ◽  
Annual Growth ◽  
The Arctic ◽  
Growth Time ◽  
Sea Ice Extent ◽  
Negative Effect

Measures of increased tundra plant productivity have been associated with the accelerating retreat of the Arctic sea-ice. Emerging studies document opposite effects, advocating for a more complex relationship between the shrinking sea-ice and terrestrial plant productivity. I introduce an autoregressive plant growth model integrating effects of biological and climatic conditions for analysing individual ring-width growth time series. Using 128 specimens of Salix arctica , S. glauca and Betula nana sampled across Greenland to Svalbard, an overall negative effect of the retreating June sea-ice extent was found on the annual growth. The negative effect of the retreating June sea-ice was observed for younger individuals with large annual growth allocations and with little or no trade-off between previous and current year's growth.

scholarly journals Late-Twentieth-Century Simulation of Arctic Sea Ice and Ocean Properties in the CCSM4

2012 ◽  
Vol 25 (5) ◽  
pp. 1431-1452 ◽  
Author(s):  
Alexandra Jahn ◽  
Kara Sterling ◽  
Marika M. Holland ◽  
Jennifer E. Kay ◽  
James A. Maslanik ◽  
...  
Keyword(s):  
Twentieth Century ◽  
Sea Ice ◽  
Internal Variability ◽  
Ice Cover ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Motion Field ◽  
Sea Ice Extent ◽  
Arctic Sea ◽  
Ensemble Mean

To establish how well the new Community Climate System Model, version 4 (CCSM4) simulates the properties of the Arctic sea ice and ocean, results from six CCSM4 twentieth-century ensemble simulations are compared here with the available data. It is found that the CCSM4 simulations capture most of the important climatological features of the Arctic sea ice and ocean state well, among them the sea ice thickness distribution, fraction of multiyear sea ice, and sea ice edge. The strongest bias exists in the simulated spring-to-fall sea ice motion field, the location of the Beaufort Gyre, and the temperature of the deep Arctic Ocean (below 250 m), which are caused by deficiencies in the simulation of the Arctic sea level pressure field and the lack of deep-water formation on the Arctic shelves. The observed decrease in the sea ice extent and the multiyear ice cover is well captured by the CCSM4. It is important to note, however, that the temporal evolution of the simulated Arctic sea ice cover over the satellite era is strongly influenced by internal variability. For example, while one ensemble member shows an even larger decrease in the sea ice extent over 1981–2005 than that observed, two ensemble members show no statistically significant trend over the same period. It is therefore important to compare the observed sea ice extent trend not just with the ensemble mean or a multimodel ensemble mean, but also with individual ensemble members, because of the strong imprint of internal variability on these relatively short trends.

Mechanisms for and Predictability of a Drastic Reduction in the Arctic Sea Ice: APPOSITE Data with Climate Model MIROC

2019 ◽  
Vol 32 (5) ◽  
pp. 1361-1380 ◽  
Author(s):  
J. Ono ◽  
H. Tatebe ◽  
Y. Komuro
Keyword(s):  
Sea Ice ◽  
Climate Model ◽  
Arctic Sea Ice ◽  
The Arctic ◽  
Ensemble Prediction ◽  
Forecast Errors ◽  
Drastic Reduction ◽  
Sea Ice Concentration ◽  
Sea Ice Extent ◽  
Arctic Sea

Abstract The mechanisms for and predictability of a drastic reduction in the Arctic sea ice extent (SIE) are investigated using the Model for Interdisciplinary Research on Climate (MIROC) version 5.2. Here, a control (CTRL) with forcing fixed at year 2000 levels and perfect-model ensemble prediction (PRED) experiments are conducted. In CTRL, three (model years 51, 56, and 57) drastic SIE reductions occur during a 200-yr-long integration. In year 56, the sea ice moves offshore in association with a positive phase of the summer Arctic dipole anomaly (ADA) index and melts due to heat input through the increased open water area, and the SIE drastically decreases. This provides the preconditioning for the lowest SIE in year 57 when the Arctic Ocean interior is in a warm state and the spring sea ice volume has a large negative anomaly due to drastic ice reduction in the previous year. Although the ADA is one of the key mechanisms behind sea ice reduction, it does not always cause a drastic reduction. Our analysis suggests that wind direction favoring offshore ice motion is a more important factor for drastic ice reduction events. In years experiencing drastic ice reduction events, the September SIE can be skillfully predicted in PRED started from July, but not from April. This is because the forecast errors for the July sea level pressure and those for the sea ice concentration and sea ice thickness along the ice edge are large in PRED started from April.

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