Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Assessment of the Seasonal and Multi-Year Variability in the Sea Ice Volume Export via the Fram Strait
Elizaveta S. Egorova & Yevgeny U. Mironov
Sea Ice Regime and Forecast Department, Arctic and Antarctic Research Institute
St. Petersburg, Russia

first time, Norwegian researchers (Vinje and Berge, 1989; Vinje et al.,1998) used ice thickness data based on the ice settlement measurements
using upward-looking sonar. Kwok et al. (2004) also used upwardlooking sonar data for the 1991–1998 period to assess the volume of ice
exported through the Fram Strait. Spreen et al. (2009) presented anassessment of the volume of exported ice cover for the period 2003–
2008, based on ICESat ice thickness observations. Krumpen et al. (2016)used the data of electromagnetic measurements of ice thickness madefrom the aircraft to estimate the amount of ice exported through the Fram
Strait for the period 2001–2012. The study (Zhang et al., 2017) assesses
the amount of exported ice for the period 1979–2012 using PIOMASS
model ice thickness data. The works (Ricker et al., 2018; Bi et al., 2018)
include assessments of the volume of ice exported through the Fram
Strait obtained for the periods 2010–2017 and 2011–2015 respectively,
according to the ice thickness data from the CryoSat-2 satellite. Finally,
Spreen et al. (2020) in their study used data on ice thickness at the strait
site, obtained using upward-looking sonars to assess the volume ofexported ice for the period 1992–2014.
In the present study, a new method is proposed for taking into accountthe thickness of the ice cover at the Fram Strait site for the subsequentassessment of the volume of exported ice. It is based on obtaining dataon the age structure of ice (hence, its average thickness) from the icemaps of the Greenland Sea made at the Arctic and Antarctic ResearchInstitute (AARI). The paper compares seasonal and interannual estimatesof the variability of the volume of ice exported through the Fram Strait,obtained using two methods for determining the drift velocity of the icecover. The assessments are presented for the period 1979–2021 and arelimited only to the winter season, from October to May, since reliabledata on the age structure of ice and its thickness are available only inthese months. The width of the ice flow at the strait site was calculated
taking into account the concentration of ice prevailing in the flow for thewinter months of the period 1997–2021. Over the same period, seasonaland interannual changes in the age structure of the ice in the Fram Strait
were analyzed.

ABSTRACTThis paper presents an assessment of the seasonal and interannual
variability of the volume of ice exported through the Fram Strait for thewinter months of 1979–2021. When assessing the values of the export
volume, we took into account the drift velocity of the ice cover, the widthof the ice flow, concerning ice concentration, as well as the thickness of
ice of various ages at the Fram Strait site. The seasonal variability of theage composition of the ice flow in the Fram Strait for the winter periodof 1997–2021 is analyzed. The seasonal cycle of changes in the average
thickness of the ice cover of various ages at the strait site is given. Two
methods for determining the volume of ice exported through the Fram
Strait are compared, which differ in the way the component of its drift
velocity is taken into account.

KEYWORDS: Fram Strait; sea ice volume flux; sea ice thickness; iceridge.

INTRODUCTION
In recent decades, Arctic sea ice has been decreasing its area and volume(Kwok, 2018; Stroeve and Notz, 2018). Although the reasons for theobserved reduction in the ice cover, most researchers associate with thewarming of the atmosphere and the ocean (e.g., Alexeev et al., 2013;
Wendisch et al., 2017), the volume of exported ice as a component of theice balance of the Arctic Ocean is still actively discussed as thecontribution to this process.
The Fram Strait is the main source of the export of thick multi-year ice
from the Arctic Basin to the Greenland Sea and further to the North
Atlantic region. According to the latest assessment (e.g., Smedsrud et al.,2017; Zamani et al., 2019), the East Greenland Current transports about
900×103 km2 of ice annually, which is equivalent to 10 % of its total areain the entire Arctic Basin.
Due to the limited data available on the ice thickness in the Fram Strait,
most of the studies are devoted to assessing the area of ice being exported
depending on the drift velocity and ice concentration (Vinje, 2001;
Kwok, 2009; Smedsrud et al., 2011; Bi et al., 2016; Smedsrud et al.,2017). However, the volume of ice exported through the Fram Strait,
which depends on the thickness distribution, is a more indicative
parameter for assessing the ice balance of Arctic sea ice. Despite thesparse observation of ice thickness in the Fram Strait both in space andin time, some researchers have attempted to assess the volume ofexported ice cover using various sources of ice thickness data. For theDATA AND METHODS
The volume of ice exported into the Greenland Sea through the Fram
Strait depends on its drift velocity, on the width of the ice flow, taking
into account the concentration of ice prevailing in the flow, and also on
the ice thickness. These components were assessed along the site in theFram Strait, a straight line drawn from Cape Norestrunningen(Greenland) to Cape Ermak (West Spitsbergen in the Spitsbergen

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