Research Documents and Reports

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Browsing Research Documents and Reports by Author "Babb, David"

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    Atmospheric Forcing Drives the Winter Sea Ice Thickness Asymmetry of Hudson Bay
    (American Geophysical Union, 2020-01-30) Kirillov, Sergey; Babb, David; Dmitrenko, Igor; Landy, Jack; Lukovich, Jennifer V.; Ehn, Jens; Sydor, Kevin; Barber, David; Stroeve, Julienne; Kirillov, Serg
    Recently, we highlighted the presence of a strong west‐east asymmetry in sea ice thickness across Hudson Bay that is driven by cyclonic circulation. Building on this work, we use satellite altimetry and a unique set of in situ observations of ice thickness from three moored upward looking sonars to examine the role of atmospherically driven ice dynamics in producing contrasting regional ice thickness patterns. Ultimately, north‐northwesterly winds coupled with numerous reversals during winter 2016/2017 led to thicker ice in southern Hudson Bay, while enhanced west‐northwesterly winds during winter 2017/2018 led to thicker ice in eastern Hudson Bay that delayed breakup and onset of the summer shipping season to coastal communities. Extending the analysis over the 40‐year satellite observation period, we find that these two different patterns of atmospheric forcing alter the timing of breakup by 30 days in eastern Hudson Bay and offer some skill in seasonal predictions of breakup.
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    Sea ice thickness in the Eastern Canadian Arctic: Hudson Bay Complex & Baffin Bay
    (Elsevier Inc., 2017-08-20) Landy, Jack; Ehn, Jens; Babb, David; Thériault, Nathalie; Barber, David
    Past observations of sea ice thickness in the Eastern Canadian Arctic (ECA) have generally been restricted to drill-hole measurements at a few local sites on landfast ice. Here we use data from the laser altimeter ICESat and the radar altimeter Cryosat-2 to present a 14-year record (2003–2016) of high-resolution and spatially extensive ice thickness observations for the ECA and identify 12 sub-regions with distinct patterns. The mean sea ice growth rate within the seasonally ice-covered ECA from November to April is 23 cm mo−1 (565 km3 mo−1 ), with the fastest increase in thickness occurring through strong ice convergence and deformation in eastern Hudson Bay and Foxe Basin. Our results demonstrate characteristically asymmetrical distributions of sea ice thickness in both Hudson Bay and Baffin Bay, but in opposing directions. In Hudson Bay the spring ice cover is 40 cm thicker in the eastern region compared to the northwestern region, whereas in Baffin Bay the ice is 20 cm thicker in the western half of the bay compared to the eastern half. In Hudson Bay we find that years with strong and positive ice drift vorticity (i.e. cyclonic and convergent conditions) correlate with increasingly asymmetrical sea ice covers, with the level of west-east asymmetry varying from 2 to 11 cm per 100 km. However, in Baffin Bay the ice drift vorticity is typically negative (i.e. anticyclonic and divergent) with no obvious link to the asymmetry of the spring ice cover. Finally, we estimate that large interannual variations in spring sea ice volume within the ECA lead to ± 15% variations in the volume of freshwater available at the ocean surface during summer.