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Quantifying Growth of Pancake Sea Ice Floes Using Images From Drifting Buoys
Author(s) -
Roach Lettie A.,
Smith Madison M.,
Dean Samuel M.
Publication year - 2018
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1002/2017jc013693
Subject(s) - sea ice , geology , arctic ice pack , polar , sea ice thickness , drift ice , arctic , sea ice growth processes , amplitude , flux (metallurgy) , climatology , geodesy , oceanography , materials science , physics , astronomy , quantum mechanics , metallurgy
New sea ice in the polar regions often begins as small pancake floes in autumn and winter that grow laterally and weld together into larger floes. However, conditions in polar oceans during freezeup are harsh, rendering in situ observations of small‐scale sea ice growth processes difficult and infrequent. Here we apply image processing techniques to images obtained by drifting wave buoys (SWIFTs) deployed in the autumn Arctic Ocean to quantify these processes in situ for the first time. Small pancake ice floes were observed to form and grow gradually in freezing, low‐wave conditions. We find that pancake floe diameters are limited by the wave field, such that floe diameter is proportional to wavelength and amplitude over time. Floe welding correlates well with sea ice concentration, and the observations can be used to estimate a key model parameter for floe size evolution. There is some agreement between observed lateral growth rates and those predicted using a theoretical model based on heat flux balance, but the model lateral growth rates are too conservative in these conditions. These results will be used to inform description of lateral floe growth and floe welding in new models that evolve sea ice floe size distribution.