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Title: Spectral attenuation of ocean waves in pack ice and its application in calibrating viscoelastic wave-in-ice models
Abstract. We investigate a case of ocean waves through a pack icecover captured by Sentinel-1A synthetic aperture radar (SAR) on 12 October 2015 in the Beaufort Sea. The study domain is 400 km by 300 km, adjacent to amarginal ice zone (MIZ). The wave spectra in this domain were reported in aprevious study (Stopa et al., 2018b). In that study, the authors divided thedomain into two regions delineated by the first appearance of leads (FAL)and reported a clear change of wave attenuation of the total energy betweenthe two regions. In the present study, we use the same dataset to study thespectral attenuation in the domain. According to the quality of SAR-retrieved wave spectrum, we focus on a range of wave numbers corresponding to9–15 s waves from the open-water dispersion relation. Wefirst determine the apparent attenuation rates of each wave number by pairingthe wave spectra from different locations. These attenuation rates slightlyincrease with increasing wave number before the FAL and become lower and moreuniform against wave number in thicker ice after the FAL. The spectralattenuation due to the ice effect is then extracted from the measuredapparent attenuation and used to calibrate two viscoelastic wave-in-icemodels. For the Wang and Shen (2010b) model, the calibrated equivalent shearmodulus and viscosity of the pack ice are roughly 1 order of magnitudegreater than that in grease and pancake ice reported in Cheng et al. (2017).These parameters obtained for the extended Fox and Squire model are muchgreater, as found in Mosig et al. (2015) using data from the Antarctic MIZ.This study shows a promising way of using remote-sensing data with largespatial coverage to conduct model calibration for various types of icecover.Highlights. Three key points: The spatial distribution of wave number and spectral attenuation in pack iceare analyzed from SAR-retrieved surface wave spectra. The spectral attenuation rate of 9–15 s waves varies around10−5 m2 s−1, with lower values in thicker semicontinuous ice fieldswith leads. The calibrated viscoelastic parameters are greater than those found inpancake ice.  more » « less
Award ID(s):
1925596
PAR ID:
10287198
Author(s) / Creator(s):
; ; ;
Date Published:
Journal Name:
The Cryosphere
Volume:
14
Issue:
6
ISSN:
1994-0424
Page Range / eLocation ID:
2053 to 2069
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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