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An Emergent Sea Ice Floe Size Distribution in a Global Coupled Ocean‐Sea Ice Model
Author(s) -
Roach Lettie A.,
Horvat Christopher,
Dean Samuel M.,
Bitz Cecilia M.
Publication year - 2018
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
eISSN - 2169-9291
pISSN - 2169-9275
DOI - 10.1029/2017jc013692
Subject(s) - sea ice , geology , joint (building) , radius , fracture (geology) , welding , spatial distribution , magnitude (astronomy) , polar , sea ice growth processes , climatology , arctic ice pack , sea ice thickness , materials science , physics , architectural engineering , remote sensing , computer security , geotechnical engineering , astronomy , computer science , engineering , metallurgy
Sea ice is composed of discrete floes, which range in size across orders of magnitude. Here we present a model that represents the joint distribution of sea ice thickness and floe size. Unlike previous studies, we do not impose a particular form on the subgrid‐scale floe size distribution. Floe sizes are determined prognostically by the interaction of five key physical processes: new ice formation, welding of floes in freezing conditions, lateral growth and melt, and fracture of floes by ocean surface waves. Coupled model results suggest that these processes capture first‐order characteristics of the floe size distribution, including decay in the distribution with increasing floe size and basin‐wide spatial variability in representative radius. Lateral melt and floe welding are particularly important, with wave fracture creating floes at preferred sizes. The addition of floe size dependence to the existing model physics results in significant reductions in sea ice concentration, particularly in summer and principally due to floe size‐dependent lateral melt. The increased lateral melt alters partitioning of the melting potential, which reduces basal melt and increases sea ice thickness in some locations. These results suggest that including a floe size distribution may be important for accurate simulation of the polar climate system.