Validating satellite derived and modelled sea-ice drift in the Laptev Sea with in situ measurements from the winter of 2007/2008

Abstract. Variability and trends in seasonal and interannual ice area export out of the Laptev Sea between 1992 and 2011 are investigated using satellite-based sea ice drift and concentration data. We found an average total winter (October to May) ice area transport across the northern and eastern Laptev Sea boundaries (NB and EB) of 3.48 × 105 km2. The average transport across the NB (2.87 × 105 km2) is thereby higher than across the EB (0.61 × 105 km2), with a less pronounced seasonal cycle. The total Laptev Sea ice area flux significantly increased over the last decades (0.85 × 105 km2 decade−1, p > 0.95), dominated by increasing export through the EB (0.55 × 105 km2 decade−1, p > 0.90), while the increase in export across the NB is smaller (0.3 × 105 km2 decade−1) and statistically not significant. The strong coupling between across-boundary SLP gradient and ice drift velocity indicates that monthly variations in ice area flux are primarily controlled by changes in geostrophic wind velocities, although the Laptev Sea ice circulation shows no clear relationship with large-scale atmospheric indices. Also there is no evidence of increasing wind velocities that could explain the overall positive trends in ice export. The increased transport rates are rather the consequence of a changing ice cover such as thinning and/or a decrease in concentration. The use of a back-propagation method revealed that most of the ice that is incorporated into the Transpolar Drift is formed during freeze-up and originates from the central and western part of the Laptev Sea, while the exchange with the East Siberian Sea is dominated by ice coming from the central and southeastern Laptev Sea. Furthermore, our results imply that years of high ice export in late winter (February to May) have a thinning effect on the ice cover, which in turn preconditions the occurence of negative sea ice extent anomalies in summer.

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Variability and trends in Laptev Sea ice outflow between 1992–2011

The Cryosphere Discussions ◽

10.5194/tcd-6-2891-2012 ◽

2012 ◽

Vol 6 (4) ◽

pp. 2891-2930 ◽

Cited By ~ 2

Author(s):

T. Krumpen ◽

M. Janout ◽

K. I. Hodges ◽

R. Gerdes ◽

F. Girard-Ardhuin ◽

...

Keyword(s):

Sea Ice ◽

Large Scale ◽

Back Propagation ◽

Late Winter ◽

Laptev Sea ◽

Concentration Data ◽

Sea Ice Extent ◽

Ice Drift ◽

Wind Velocities ◽

The Laptev Sea

Abstract. Variability and trends in seasonal and interannual ice area export out of the Laptev Sea between 1992 and 2011 are investigated using satellite-based sea ice drift and concentration data. We found an average winter (October to May) ice area transport across the northern and eastern Laptev Sea boundaries (NB and EB) of 3.48 × 105 km2. The average transport across the NB (2.87 × 105 km2) is thereby higher than across the EB (0.61 × 105 km2), with a less pronounced seasonal cycle. The total Laptev Sea ice area flux significantly increased over the last decades (0.85 × 105 km2/decade, p > 0.95), dominated by increasing export through the EB (0.55 × 105 km2/decade, p > 0.90), while the increase in export across the NB is small (0.3 × 105 km2/decade) and statistically not significant. The strong coupling between across-boundary SLP gradient and ice drift velocity indicates that monthly variations in ice area flux are primarily controlled by changes in geostrophic wind velocities, although the Laptev Sea ice circulation shows no clear relationship with large-scale atmospheric indices. Also there is no evidence of increasing wind velocities that could explain the overall positive trends in ice export. Following Spreenet al. (2011), we therefore assume that changes in ice flux rates may be related to changes in the ice cover such as thinning and/or a decrease in concentration. The use of a back-propagation method revealed that most of the ice that is incorporated into the Transpolar Drift is formed during freeze-up and originates from the central and western part of the Laptev Sea, while the exchange with the East Siberian Sea is dominated by ice coming from the Central and South-Eastern Laptev Sea. Furthermore, our results imply that the late winter (February to May) ice area flux may at least partially control the summer sea ice extent in the Laptev Sea.

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Opportunistic evaluation of modelled sea ice drift using passively drifting telemetry collars in Hudson Bay, Canada

10.5194/tc-2020-26 ◽

2020 ◽

Author(s):

Ron R. Togunov ◽

Natasha J. Klappstein ◽

Andrew E. Derocher ◽

Nicholas J. Lunn ◽

Marie Auger-Méthé

Keyword(s):

Sea Ice ◽

Large Scale ◽

The Arctic ◽

Hudson Bay ◽

Gps Telemetry ◽

In Situ Data ◽

Ice Drift ◽

Sea Ice Drift ◽

Drift Direction

Abstract. Sea ice drift plays a central role in the Arctic climate and ecology through its effects on the ice cover, thermodynamics, and energetics of northern marine ecosystems. Due to the challenges of accessing the Arctic, remote sensing has been used to obtain large-scale longitudinal data. These data are often associated with errors and biases that must be considered when incorporated into research. However, obtaining reference data for validation is often prohibitively expensive or practically unfeasible. We used the motion of 20 passively drifting high-accuracy GPS telemetry collars originally deployed on polar bears, Ursus maritimus, in western Hudson Bay, Canada to validate a widely used sea ice drift dataset produced by the National Snow and Ice Data Centre (NSIDC). Our results showed that the NSIDC model tended to underestimate the horizontal and vertical (i.e. u and v) components of drift. Consequently, the NSIDC model underestimated magnitude of drift, particularly at high ice speeds. Modelled drift direction was unbiased, however was less precise at lower drift speeds. Research using these drift data should consider integrating these biases into their analyses, particularly where absolute ground speed or direction is necessary. Further investigation is required into the sources of error, particularly in under-examined areas without in situ data.

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Correlation between Arctic river discharge and sea ice formation in Laptev Sea using sea surface salinity from SMOS satellite

10.5194/egusphere-egu2020-10052 ◽

2020 ◽

Author(s):

Carolina Gabarro ◽

Justino Martinez ◽

Veronica Gonzalez-Gambau ◽

Cristina González-Haro ◽

Estrella Olmedo ◽

...

Keyword(s):

Sea Ice ◽

Spatial Resolution ◽

Sea Surface ◽

Sea Surface Salinity ◽

The Arctic ◽

Laptev Sea ◽

Ice Melting ◽

Surface Salinity ◽

The Laptev Sea

During the last 3 decades, the Arctic rivers have increased their discharge around 10%, mainly due to the increase of the global atmospheric temperature. The increase of the river discharge carries higher loads of dissolved organic matter (DOM) and suspended matter (SM) entering to the Arctic Ocean. This results in increased absorption of solar energy in the mixed layer, which can potentially contribute to the general sea ice retreat. Observation based studies (e.g. Bauch et al., 2013) showed correlation between river water discharge and local sea ice melting on the Laptev sea shelf due to the change on the ocean heat. Previous studies are based with a limited number of observations, both in space and in time.Thanks to the ESA SMOS (Soil Moisture and Ocean Salinity) and NASA SMAP (Soil Moisture Active Passive) missions we have daily the sea surface salinity (SSS) maps from the Arctic, which permit to observe the salinity variations due to the river discharges. The Arctic sea surface salinity products obtained from SMOS measurements have been improved considerable by the Barcelona Expert Center (BEC) team thanks to the project Arctic+Salinity, funded by ESA. The new version of the product (v3) covers the years from 2011 up to 2018, have a spatial resolution of 25km and are daily maps with 9 day averages. The Arctic+ SSS maps provide a better description of the salinity gradients and a better effective spatial resolution than the previous versions of the Arctic product, so the salinity fronts are better resolved. The quality assessment of the Arctic+SSS product is challenging because, in this region, there are scarce number of in-situ measurements.The high effective spatial resolution of the Arctic+ SSS maps will permit to study for the first time scientific physical processes that occurs in the Arctic. We will explore if a correlation between the Lena and Ob rivers discharge with the sea ice melting and freeze up is observed with satellite data, as already stated with in-situ measurements by Bauch et al. 2013. Salinity and sea ice thickness maps from SMOS and sea ice concentration from OSISAF will be used in this study.&#160;Bauch, D.,H&#246;lemann, J. , Nikulina, A. , Wegner, C., Janout, M., Timokhov, L. and Kassens, H. (2013): Correlation of river water and local sea-ice melting on the Laptev Sea shelf (Siberian Arctic) , Journal of Geophysical Research C: Oceans, 118 (1), pp. 550-561 . doi: 10.1002/jgrc.20076

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Opportunistic evaluation of modelled sea ice drift using passively drifting telemetry collars in Hudson Bay, Canada

The Cryosphere ◽

10.5194/tc-14-1937-2020 ◽

2020 ◽

Vol 14 (6) ◽

pp. 1937-1950

Author(s):

Ron R. Togunov ◽

Natasha J. Klappstein ◽

Nicholas J. Lunn ◽

Andrew E. Derocher ◽

Marie Auger-Méthé

Keyword(s):

Sea Ice ◽

Large Scale ◽

The Arctic ◽

Hudson Bay ◽

Gps Telemetry ◽

In Situ Data ◽

Ice Drift ◽

Sea Ice Drift ◽

Drift Direction

Abstract. Sea ice drift plays a central role in the Arctic climate and ecology through its effects on the ice cover, thermodynamics, and energetics of northern marine ecosystems. Due to the challenges of accessing the Arctic, remote sensing has been used to obtain large-scale longitudinal data. These data are often associated with errors and biases that must be considered when incorporated into research. However, obtaining reference data for validation is often prohibitively expensive or practically unfeasible. We used the motion of 20 passively drifting high-accuracy GPS telemetry collars originally deployed on polar bears, Ursus maritimus, in western Hudson Bay, Canada, to validate a widely used sea ice drift dataset produced by the National Snow and Ice Data Center (NSIDC). Our results showed that the NSIDC model tended to underestimate the horizontal and vertical (i.e., u and v) components of drift. Consequently, the NSIDC model underestimated magnitude of drift, particularly at high ice speeds. Modelled drift direction was unbiased; however, it was less precise at lower drift speeds. Research using these drift data should consider integrating these biases into their analyses, particularly where absolute ground speed or direction is necessary. Further investigation is required into the sources of error, particularly in under-examined areas without in situ data.

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