IASC –CWG NAG workshop summary report«Scientific seminar on the Importance of Calving for the Mass Balance of Arctic Glaciers»15-17 October 2016, Institute of Oceanology, Polish Academy of Sciences, Sopot, Poland
Overview
The Centre for Polar Studies, together with the IASC Cryosphere Working Group and the IASC Network
on Arctic Glaciology hosted a scientific seminar on the “Importance of Calving for the Mass Balance ofArctic Glaciers”, 15-17 October 2016. Venue was the Institute of Oceanology, Polish Academy of
Sciences, 55 Powstańców Warszawy Str., 81-712 Sopot, Poland. There were about 25 participants
representing 9 IASC member countries and states adjoining the Arctic, including Russia, Norway, Canada
and the US. The workshop agenda/program and participant list is attached to this report.
Main scientific objective
What is the current ice discharge of Northern Hemisphere Glaciers and ice caps to the ocean?
Secondary objectives
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What is the temporal variability of ice mass loss at marine glacier termini?
What is the relative contribution of iceberg discharge/frontal ablation to total ice -mass loss?
How does frontal ablation differ from region to region within the Arctic?
Review terminology to describe mass loss at the glacier termini
Review methods of determining frontal ablation
Provide recommendations concerning terminology and methods

Scope of the workshop
Bring together international experts on methods to derive calving flux/frontal ablation, covering field
methods, remote sensing and modelling. Bring together experts working on the various regions of the
Arctic, namely the Russian Arctic, Svalbard, the Canadian Arctic, Alaska and peripheral Greenland. The
first day of the workshop was used to present and discuss terminology and methods. On the second day,results and key data were presented on the various regions and regional challenges were discussed. The
last day was reserved for continued discussions and making plans for how to follow up the objectives of
the workshop.
Expected outcome of the workshop
1. a paper that will provide the first measure of northern hemisphere ice discharge to the ocean
over the period ~2000-2015 for all glaciers and ice caps (including the periphery of Greenland,but excluding the Greenland ice sheet)
2. a report with recommendations on terminology and methods related to ice mass loss at themarine terminus of tidewater glaciers

1Background:
From IPCC AR5: Over the last two decades, glaciers and ice caps in the Arctic, as well as the Greenland
ice sheet continued to lose mass at accelerating rates. The annual mean Arctic sea ice extent decreased
over the period 1979 to 2012, with especially large losses in summer extent. These changes coincidewith atmospheric and oceanic warming at high latitudes (Arctic amplification of the observed global
warming).
Neglect of calving flux estimates has led to underestimates of mass loss from Arctic glaciers and ice caps
and thus, underestimation of the contribution to global sea-level rise (SLR). Total calving loss from Arctic
glaciers and ice caps was previously estimated to ~35 Gt (Van Wychen, 2014). But the estimates for thevarious sub regions were derived for different time periods and using different methods, all of whichhave associated uncertainties. This estimate also excludes peripheral Greenland, i.e. glaciers and ice
caps outside the ice sheet.
Data required for regional assessment of frontal ablation
The ice discharge to the ocean is usually expressed as the ice flux through a fluxgate near the marine
terminus and the advance/retreat rate of the terminus.
We need to know:
1. Ice velocity at fluxgate
2. Ice thickness and width, i.e. cross-sectional area of the fluxgate
3. Rate of terminus retreat/advanceIn addition, we need to have a complete inventory of tidewater glaciers for the entire Arctic
Scientific highlights with regards to terminology and methods
1. Different terms have been used to describe mass loss at the glacier termini – calving flux,
dynamic discharge, ice discharge, frontal ablation, ice flux, iceberg production. However, inprevious literature they have not always been clearly defined and at times used interchangeably.
There is therefore a need to define what these terms really mean. We decided to follow thedefinition of the recently published “Glossary of glacier mass balance and related terms” byCogley et al., 2011. “Frontal ablation” includes iceberg production as well as subaqueous andsubaerial melting, where the calving front is in contact with water or air.
2. It was pointed out that currently available data and models allow assessment of total frontal
ablation, however, we cannot distinguish between iceberg production and submarine melting
on a pan-Arctic scale.
3. We agreed that during this workshop, we will not go into details with respect to mechanisms oficeberg calving / frontal ablation.
4. Frontal ablation is usually assessed as the balance between the ice flux towards the terminus
and changes in the position of the terminus. We discussed whether or not terminus retreat andadvance can be excluded from our pan-Arctic estimate. Presentations from various regions,2foremost Svalbard and the Russian Arctic, showed that marginal retreat can be as important as
the ice flux term and should therefore be included.
5. How does frontal ablation translate to SLR contribution? If terminus advance and retreat is
considered, this allows for separate estimates on ice-mass loss and sea-level rise contribution. A
marine terminus that advances into the sea will lead to an instantaneous replacement of sea
water and hence contribution to SLR, even when frontal ablation may be negligible.

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With respect to the above data needs:
Glacier inventories for the entire Arctic are provided by the Randolph Glacier Inventory and the
GLIMS database. The marine terminus can be extracted from the provided glacier outlines.
Ice velocities should ideally present annual averages, but we often have winter snapshots. We
discussed seasonal variations in glacier flow and frontal ablation. At Hornsund, Svalbard, forexample, glacier flow during winter is at 90-95% of their annual average. This may not be thecase in years with winter rainfall, when velocities can be above the annual average. We alsoneed depth-averaged velocities, whereas observed velocities reflect ice-surface velocities, only.
Changes in terminus position change (retreat/advance rate) can be derived from topographic
maps, satellite images or field measurements.
Ice thickness data is only available for some key glaciers. Ground-based ice thickness surveys
often do not extend towards the calving front, whereas airborne surveys often only covercenterline profiles. In case of the latter, the centerline thickness can be scaled by a shape factor.
Where available, bathymetric data in front of the tidewater glaciers can be used to assess thegeneral shape and ice thickness of the terminus. Where no data is available, theoretical
approaches can be used, which are based on principles of glacier dynamics or inversion fromsurface geometry, velocities and mass balance, calibrated against available data. The simplest
approach in assessment of ice discharge is scaling of width and velocity.

10. Alternative approaches to estimate the mass loss through iceberg calving were discussed. These
include calving estimates from seismic or acoustic records. For individual glaciers, models can becalibrated to relate seismic attributes to calving volume. Challenges are the separation ofindividual glacier-seismic sources, encompassing seismic noise originating in the hydrologic
drainage system, slip-stick motion at the glacier bed, formation of surface crevasses,
hydrofracturing and iceberg calving. Calibrated models may only work for the glaciers for whichcalibration data is available, i.e. independent estimates of calving event size or frontal ablation
over certain time periods. Another approach presented was deriving DEM’s of ice mélange,
paired with residence times.
11. With respect to modelling: Calving processes are still not well understood. In addition, both theclimatic forcing and the ice geometry not well constrained. Two schools of models exist. The firstis based on empirical relations, such as water depth, the second on physical processes, such as
crevasse penetration and damage.

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Scientific highlights for the various regions
For each region, previous estimates of calving flux / frontal ablation were presented. We discussed theavailability of ice thickness data, glacier velocity and changes in terminus position and the regional data
constraints.
1. Where are floating and grounded marine termini? This affects calving processes, calving event
size and rates.
2. What are the timescales of calving? These range from instantaneous (process studies), toseasonal (winter vs summer) and annual to decadal (incl. surging), centuries and longer (glacial
cycles).
3. What drives seasonal variation in calving flux: ice dynamics, atmospheric and oceanic forcing,
this means surface melt and its influence on enhanced basal motion and crevasse fracturing, as
well as subaqueous melt and destabilization of the calving front by undercutting.
4. What is the importance of glacier surges?
5. The pan-Arctic study area was defined to include all Arctic glaciers and ice caps in Alaska, theCanadian Arctic, Svalbard, the Russian Arctic and peripheral Greenland (excluding the Greenland
ice sheet)
6. The Russian Arctic contains small ice shelves. Until recently, glaciers and ice caps in the Russian
Arctic are not known to be of surge-type. In recent years, however, several glaciers started
surging, including the Vavilov ice cap on Severnaya Zemlya, which has advanced 10 km into theocean with a surface velocity of >5 km/yr.
7. Tidewater glaciers on Svalbard are well-grounded on the sea floor. Many glaciers are of surgetype. Surging glaciers are major decadal contributors to calving-mass loss and need to beaccounted for. The Basin-3 surge of the Austfonna ice cap has been ongoing for 5 years. The
resulting annual ice mass loss matches previous estimates of calving from the entire archipelago
and a current doubling of the Svalbard ice-mass loss. In the recent decade, Svalbard has
experienced several large surges – besides Basin-3, Nathorsbreen and Stonebreen on Edgeøya.
8. Surging leads to shortly increased ice flux and short –term advance, followed by a long-term
retreat of the marine terminus. This results in an instantaneous SLR contribution followed by along-term frontal ablation/ice-mass loss. Considerable advances related to glacier surges resultin instantaneous SLR contribution, even in case of negligible iceberg calving loss/frontal ablation.
9. Do terminus advances or retreats need to be accounted for? Yes, because for some regions, e.g.
Svalbard and the Russian Arctic, ice mass loss due to terminus retreat may be larger as the ice
flux towards the calving front. For Austfonna, 60% of the drainage basins were reported to be
dominated by marginal retreat and only 40% by the ice-flux towards the calving front. For
glaciers in Hornsund, southern Spitsbergen, 30% of the ice mass loss at the calving front was
attributed to terminus retreat and 70% to the ice-flux component. What is the proportion of
total mass loss from frontal ablation vs meltwater runoff?
10. The Canadian Arctic is a relatively small contributor to total Arctic glacier and ice cap dynamic
discharge, accounting for less than 10% of the reported pan-Arctic discharge. 98% of theicebergs producing glaciers are located in the northern CAA. Two tidewater glaciers, Trinity and4Wykeham Glacier were responsible for ~62% of the total icebergs produced in 2015. In the
Canadian Arctic, surface melt exceeds ice mass loss by calving. This may be different for colder
regions and where a large fraction of the glacier area is drained through tidewater glaciers, suchas Svalbard or the Russian Arctic.
11. Alaska: Many tidewater glaciers have retreated to the shorelines. Two glaciers, Hubbard andColumbia, dominate the total frontal ablation in Alaska. During 1996-2007, Columbia Glacier
was one of the largest individual contributors to global SLR (about 1% of the eustatic SLR at thattime).
12. Greenland Ice Sheet: Most of the ice discharge occurs from a few glaciers. The Greenland Ice
Sheet contributes ~1 mm to global SLR per year, approximately evenly split between calving andsurface meltwater runoff (van den Broeke, 2016). This estimate excludes peripheral glaciers andice caps. Glacier outlines of peripheral glaciers are not well defined in the GLIMS glacierdatabase, i.e. not very well distinguished from basins of the ice sheet.
13. Most regions have a small number of key glaciers that are responsible for a major part of thecurrent ice discharge. Efforts should be made to monitor these key glaciers in more detail.
Guidelines & common methods to be used in the Pan-Arctic assessment of frontal ablation
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terminus retreat/advance should be investigated over the past decade (~2000-2015) andaveraged over the terminus width, not just centerline
assume recent velocities are representative of the past 10 years
0.9 depth averaged velocity compared to surface
winter velocity 90% of annual mean
ice density = 900 kg m3
where available, use cross-sectional ice thickness and velocity estimate to calculate flux
use error estimate to deal with implementation of results from “non-standard” methods
glaciers surges should be included, but clearly flagged as such

References
Cogley; J.G.; Hock; R.; Rasmussen; L.A.; Arendt; A.A.; Bauder; A.; Braithwaite; R.J.; Jansson; P.; Kaser; G.;
Möller; M.; Nicholson; L. and Zemp M. Glossary of Glacier Mass Balance and Related Terms and IHP-VII
Technical Documents in Hydrology No. 86 and IACS Contribution No. 2 UNESCO-IHP, 2011
Van Wychen; W.; Burgess; O., D.; Gray; L.; Copland; L.; Sharp; M.; Dowdeswell; A., J.; Benham & J., T.
Glacier velocities and dynamic ice discharge from the Queen Elizabeth Islands and Nunavut and Canada
Geophysical Research Letters, 2014

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Scientific Seminar on"Importance of calving for mass budget of Arctic glaciers"
with focus on ice mass loss at fronts of tidewater glaciers in Pan-Arctic scale
Sopot, Poland – 15-17 October 2016
The seminar will be hosted and financially supported by the Centre for Polar Studies - University of Silesia
and Institute of Oceanology Polish Academy of Sciences, Poland under the umbrella and with support of
the International Arctic Science Committee (IASC), through its Network on Arctic Glaciology, and theCommittee of Polar Research Polish Academy of Sciences.
The purpose of the seminar is to:a) assess the current knowledge on ice mass loss at fronts of Arctic tidewater glaciers;b) provide a consistent description of methodologies and terminologies so that inter-comparison
between Arcti c regions will be more feasible;c) consider estimation of discharge for regions where they currently do not exist;d) assess the importance of frontal mass loss for the general mass budget of glaciers in different Arctic
regi ons.
Participation:
The semi nar will bring together invited experts on Arctic calving glaciers and mass balance (ca. 20
peopl e) and is open to everyone interested in these issues. The total number of participants is limited to
40 persons.
Four - five working session are planned with 1-2 invited introductory talks and longer time slot for
di scussion during each. Uninvited presentations are not expected. Nevertheless, brief interventions on
methods and regional data/results (up to 5 min.) could be possible.
Expected seminar outcome:A report with recommendations for further coordinated activity and sketch of an overview paper(s) onal ready gained knowledge on frontal ablation and dynamic discharge of mass as a part of mass balanceof Arcti c glaciers.
Registration:
Everyone i ntending to attend the seminar is asked to submit short (maximum 300 words) motivationl etter by email to Jacek Jania (jam.jania@gmail.com). Registration deadline is September 15, 2016. When

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number of applications exceeds the limit the Steering Committee reserves the right to decide on
participation. The confirmation of the participation will be sent to applicants soon after registration
deadline.
The regi stration fee of 430 PLN (c. 100 EUR) have to be paid on-site in cash. The registration fee i ncludes
coffee breaks and lunches during the meeting, the icebreaker and the seminar dinner.
Financial support:
The IASC Network on Arctic Glaciology (NAG) has some opportunity for financial support, provided by
IASC, of early career scientists to allow them to attend the seminar. Those interesting are asked to send
an application to Jacek Jania (jam.jania@gmail.com) containing motivation letter including name,affiliation, age, supervisors, basic description (maximum 300 words) of the pursued research project,
i nformation on amount of money requested and its justification (registration, travel and lodging
expenses allowed). The decision on granting will be sent to applicants soon after registration deadline.
Note that the support will be reimbursed after the seminar.
Venue, accommodation and travel information:
The venue and l ocal organization will be provided by the Centre for Polar Studies - Institute of
Oceanology, Polish Academy of Sciences in Sopot (http://www.iopan.gda.pl/index.html).
Sopot i s a famous seaside resort having wide range of accommodation options. The full list of hotels canbe found at: http://www.sts.sopot.pl/.
The nearest airport with the convenient flight connections is Gdańsk Lech Wałęsa Airport(http://www.airport.gdansk.pl/). The airport is located ca. 10 km from the seminar venue, with a varietyof l ocal transport options (http://www.airport.gdansk.pl/passenger/departure1/drive).

Steering Committee of the Seminar:
Thorben Dunse – Chair of the IASC NAG
Francisco Navarro – Chair CWG IASC
Luke Copland – Initiator of this direction of co-operative studies
Mari usz Grabiec – Polish Representative to the NAG - Local host - Centre for Polar Studies – Univ. of Silesia
Waldemar Walczowski – Centre for Polar Studies - Institute of Oceanology, PAS - Local hostJacek A. Jania – Head, Centre for Polar Studies

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"Importance of calving for mass budget of Arctic glaciers"
Sopot Scientific Seminar on Ice Calving in the Arctic (3SICA)

15-17 October, Sopot, Poland
Program
14 October 2016 – Friday: arrival of participants; Steering Committee Meeting (18.00)
19.00: Icebreaker & supper ("Browar LUBROW" TAP HOUSE, ul. Bohaterów Monte Casino 60, Sopot)
15 October 2016 – Saturday
9.30: Welcome and opening
Introductory session (on aim and scope of the meeting – initiatory remarks - L. Copland, J. Jania;
importance of outcomes for oceanographers – W. Walczowski; open questions related to calving
processes in the Arctic and clarification of definitions – J.O. Hagen, A.F. Glazovsky) + discussion.
10.45: Coffee break
11.00: Methodology session 1 (studies of calving mass loss - state of the art; required data; field
methods and techniques) – T. Dunse, M. Blaszczyk, F.T. Walter + discussion.
13.00-14.00: Lunch
14.00: Methodology session 2 (studies of calving mass loss – remote sensing methods) – J. Bassis,
E. Enderlin, L. Copland + discussion
15.45: Tea / coffee break
16.00: Methodology session 3 (common methods, suggestions for unification and recommendations)– F. Navarro, J. Bassis* + discussion (*TBC)
19.00: Supper (Restaurant “Smak Morza”, Aleja Franciszka Mamuszki 2, Sopot)
16 October 2016 – Sunday
9.00: Results from regions of the Arctic and key glaciers – J. Dowdeswell – a general introduction
Part 1 – Svalbard – J.O. Hagen/T. Dunse, G. Mohold, M. Blaszczyk;
Part 2 – Russian Arctic – I.V. Buzin, A.F. Glazovsky;
10.45: Coffee break
11.00: Part 3 – Canadian Arctic – L. Copland, A. Dalton; Part 4 – Alaska – B. McNabb + discussion.
12.45 -13.30: Lunch
13.30: Results from regions ctd. Part 5 – Greenland - E. Enderlin, F.T. Walter, and Part 6 – Gaps
in a Pan-Arctic knowledge of calving glaciers (insights from different perspectives – L. Copland,
J. Dowdeswell, J. Jania) + general discussion.
15.30: Tea / coffee break
15.45: Time for local sightseeing / rest or continuation of sessions
19.30: 3SICA Dinner (Restaurant “Hotel Haffner” ul. Jana Jerzego Haffnera 59, Sopot)
17 October 2016 – Monday
9.00: Summary session with preparation of recommendations and a draft of the report fromthe meeting (possible work in subgroups: moderators TBD).
10.30: Coffee break
12.00: Concluding session and closing of the seminar (structure – TBD)
13.00: Lunch
Steering Committee of the Seminar:
Thorben Dunse - Chair of the IASC NAG, Norway
Francisco Navarro - Chair CWG IASC, Spain
Luke Copland - Initiator of this direction of co-operative studies, Canada
Mariusz Grabiec - Polish Representative to the NAG - Local host - Centre for Polar Studies – University of Silesia, Poland
Waldemar Walczowski – Local host - Centre for Polar Studies - Institute of Oceanology, PAS, Poland
Jacek A. Jania - Head, Centre for Polar Studies, Poland

Venue: Institute of Oceanology, Polish Academy of Sciences,
55 Powstańców Warszawy Str., 81-712 Sopot, Poland
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"Importance of calving for mass budget of Arctic glaciers"
Sopot Scientific Seminar on Ice Calving in the Arctic (3SICA)

15-17 October, Sopot, Poland

List of participantsName

Affiliatione-mailJeremy N. Bassis

University of Michigan

jbassis@umich.edu

USA

Małgorzata Błaszczyk

University of Silesia

mbl4@wp.pl

PolandIgor Vladimirovich
Buzin

Arctic and Antarctic ResearchInstitute St. Petersburg

buzin@aari.ru

RussiaAlison Cook

Durham University

alison.cook@durham.ac.uk

U.K.

Luke Copland

University of Ottawa

luke.copland@uottawa.ca

CanadaAbigail Dalton

University of Ottawa

adalt043@uottawa.ca

CanadaJulian Dowdeswell

University of Cambridge

jd16@cam.ac.uk

Thorben Dunse

University of Oslothorben.dunse@geo.uio.no

NorwayEllyn Enderlin

University of Maine

ellyn.enderlin@gmail.com

USA

Eva Falck

University Centre in Svalbard– UNIS, Longyearbyen

Eva.Falck@unis.no

NorwayAndrey F. Glazovsky

Institute of Geography RAS,
Moscow

glazovsky@gmail.com

RussiaPiotr Głowacki

Institute of Geophysics PAS

glowacki@igf.edu.pl

PolandMariusz Grabiec

University of Silesia

mariusz.grabiec@us.edu.pl

PolandJon Ove Hagen

University of Osloj.o.m.hagen@geo.uio.no

NorwayAndrew Hodson

University of Sheffield

A.J.Hodson@sheffield.ac.uk

U.K.

Dariusz Ignatiuk

University of Silesia

dignatiuk@gmail.com

PolandJacek A. Jania

University of Silesia

jam.jania@gmail.com

PolandBob McNabb

University of Oslorobert.mcnabb@geo.uio.no

NorwayGeir Moholdt

Norwegian Polar Institutegeir.moholdt@npolar.no

NorwayFrancisco Navarro

Universidad Politécnica deMadridfrancisco.navarro@upm.es

Spain

University of Chile, Santiago

dieter.tetz@gmail.com

Chile

University of Gdansk
Institute of Oceanology PAS,Sopot
ETH Zurich

jackurbanski@gmail.com

Polandwalczows@iopan.gda.pl

Polandfwalter@vaw.baug.ethz.ch

Switzerland

Dieter Rudolf Tetzner
IvovichJacek Urbanski
Waldemar Walczowski
Fabian Walter+ PhD students

Country

U.K.

Poland9