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ASPECt (sea ice processes & climate)

The Expert Group on Antarctic Sea-ice Processes and Climate (ASPeCt) aims to improve our understanding of the Antarctic sea ice zone through focussed and ongoing field programmes, remote sensing and numerical modelling.

ASPeCt is an expert group on multi-disciplinary Antarctic sea ice zone research within the SCAR Physical Sciences programme. Established in 1996, ASPeCt has the key objective of improving our understanding of the Antarctic sea ice zone through focussed and ongoing field programmes, remote sensing and numerical modelling. The programme is designed to complement, and contribute to, other international science programmes in Antarctica as well as existing and proposed research programmes within national Antarctic programmes. ASPeCt also includes a component of data rescue of valuable historical sea ice zone information.

About

For more information, visit the ASPeCt website.

The overall aim of ASPeCt is to understand and model the role of Antarctic sea ice in the coupled atmosphere-ice-ocean system. This requires an understanding of key processes, and the determination of physical, chemical, and biological properties of the sea ice zone. These are addressed by objectives which are:

To establish the distribution of the basic physical properties of sea ice that are important to air-sea interaction and to biological processes within the Antarctic sea-ice zone (ice and snow cover thickness distributions; structural, chemical and thermal properties of the snow and ice; upper ocean hydrography; floe size and lead distribution). These data are required to derive forcing and validation fields for climate models and to determine factors controlling the biology and ecology of the sea ice-associated biota.
To understand the key sea-ice zone processes necessary for improved parameterisation of these processes in coupled models.

The key scientific questions which must be answered to meet the objectives of the ASPeCt Programme are:

What are the broad-scale time-varying distributions of the ice and snow-cover thickness, ice composition and other physical characteristics in the Antarctic sea ice zone?
What are the dominant processes of ice formation, modification, decay and transport which influence and determine ice-thickness, composition and distribution?
What is the role of coastal polynyas in determining total ice production, heat, salt and biogeochemical fluxes, and water mass modification?
What are the processes that control the ice-water interactions at the ice-edge, and their seasonal changes?

For more details, visit the ASPeCt website.

ASPeCt’s Main Themes or Study Areas:

Snow and Sea Ice Climatology (Ship Obs)
Snow and Ice Properties (Cores, Thickness, Sampling)
Time Series of Sea Ice Processes (Drifting Stations and Ice Mass Balance Buoys) Coastal Polynya Process Experiments
Ice Edge Process Experiments
Validation of Remote Sensing for application in Sea Ice Modeling Coordination of sea ice observations from coastal stations (AFIN-Antarctic Fast Ice Network)

Key Questions that ASPeCt addresses:

How is Antarctic sea ice responding to global change? Why is Antarctic sea ice extent increasing?
How important is the sea ice for the ecosystem?
What is the role of the sea ice pump for CO2 exchange between ocean and atmosphere? How is sea ice thickness changing?
What is the role of snow processes?
How can we distinguish climate trends from inter-annual variability? What variables control the predictability of sea ice?

Activities:

ASPeCt Metadata in the Global Change Master Directory.
Development of ice cameras to be used automatically on ships of opportunity.
Organize sessions at SCAR Open Science Conferences and other meetings.
Coordination with SOOS, IICWG (International Ice Chart Working Group).
Planning to develop data archives for AUV under ice data, aerial photography, airborne lidar, (from manned and unmanned aircraft).

ASPeCt organizational structure

ASPeCt has a leadership structure consisting of a Vice-Chair, Chair, Immediate past Chair, Early Career Scientist (ECS). The Vice- Chair serves for at least two years. The Chair serves for at least four years. The Immediate Past Chair Serves for at least two years. Each post is renewable/extendable in two-year increments. The Vice-Chair does not automatically become Chair and there is the opportunity for the leadership to be renewed every two years.

Two other positions within the leadership structure consist of an appointed ASPeCt Representative on SOOS (if appointed by SOOS then on their SSC, or ex-officio if not on the SSC) and an appointed Communication and Data Executive (typically at the AAD where the ASPeCt database, website, etc are currently housed).

Terms of Reference

ASPeCt Science and Implementation Plan

Executive Summary

The ASPeCt program aims to improve our understanding of sea ice physical processes and ocean-atmosphere interaction in the sea-ice zone. As a SCAR program, ASPeCt is focused on the unique regional environment of the Antarctica, but is closely linked to the global climate change research agenda through SCAR’s “Antarctica and the Global Climate System” (AGCS) program. The inter-disciplinary components of ASPeCt are designed to contribute to, and extend, other international climate, ocean and biology programs.

The primary objectives of ASPeCt are:

To determine the spatial and temporal variability of the basic physical properties of sea ice that are important to air-sea interaction and to biological processes within the Antarctic sea-ice zone (ice and snow cover thickness distributions; structural, chemical and thermal properties of the snow and ice; upper ocean hydrography; floe size and lead distribution); and
To understand the key sea-ice zone processes necessary for improved parameterisation of these processes in coupled models.

Important problems remaining to be adequately covered by Antarctic sea ice research programs include:

The broad climatology of sea ice physical characteristics;
Processes such as ice formation, water mass modification, the maintenance of polynyas, ice edge and coastal fronts, gas exchange, and atmosphere-ice-ocean interaction; and
Modelling sea-ice processes in coupled atmosphere-ice-upper ocean models and linking scales from local to regional to global scales in models.

The ASPeCt program will build on existing and proposed research programs, and the shipping activities of national Antarctic operators. It will also include a component of data-rescue of valuable historical sea ice zone information. The ASPeCt program will achieve its aims by:

Maintaining an ongoing system of quantified shipboard observations that provides statistical descriptions of ice and snow thickness distributions;
Identifying important data rescue projects that can provide quantitative historical sea ice zone information;
Conducting ship-based process experiments at coastal polynyas, ice edges and interior pack ice zones;
Integrating ASPeCt observations and experiments with complementary efforts in drifting buoys, upward looking sonar, satellite records and physical oceanography; and
Providing validation and input data on ice properties and processes for coupled numerical models and satellite-based sensors.

Download the full Science and Implementation Plan

News

View in all ASPeCT

News and Updates from the Sea-Ice Processes Community.

Members

Contact

The chair of the ASPeCt group is Marilyn Raphael.

Membership

Marilyn Raphael, Chair (USA)
Steve Ackley, Immediate Past Chair (USA)
Petra Heil, Data and Communications Officer (Australia)
Stefanie Arndt, Junior Officer (Germany)
Kay Ohshima (Japan)
Martin Vancoppenolle (France)
Rob Massom (Australia)
Ted Maksym (USA)
Thorsten Markus (USA)
Pat Langhorne (New Zealand)
Hyoung Chul Shin (Korea)
Elizabeth Hunke (USA)
Marcel Nicolaus (Germany)
Klaus Meiners (Australia)
Sharon Stammerjohn (USA)
Ron Kwok (USA)
Timo Vihma (Finland)
Jean Louis Tison (Belgium)

A list of members of the ASPeCt Scientific Steering Group is available on the ASPeCt website.

Resources

Publications, Data and Links of interest to the Antarctic sea ice community

Reports

Toggle	Title	Date
	pdf ASPeCt Expert Group Report 2022 ( pdf, 218 KB )	11 Jan 2023
	pdf ASPeCt Expert Group Report 2020 ( pdf, 140 KB )	16 Apr 2021
	pdf SCAR 2020 Parallel Session 5: Sea Ice Variability and Change ( pdf, 22 KB )	21 Jul 2020
	pdf ASPeCt Expert Group Report 2019 ( pdf, 74 KB )	16 Sep 2019
	pdf SCAR EXCOM 2019 Paper 14: Report from Physical Sciences Group ( pdf, 106 KB )	05 Sep 2019
	pdf SCAR XXXV Paper 17: Physical Sciences Group (PSG) Report ( pdf, 755 KB )	20 Sep 2018
	pdf SCAR EXCOM 2017 Paper 4: Report of Physical Sciences Group AND Physical Sciences Group Reports ( pdf, 964 KB )	02 Aug 2017
	pdf SCAR XXXIV WP06b: Physical Sciences Action and Expert Group Reports ( pdf, 1.77 MB )	30 Aug 2016

Publications

Recent papers:

Drews, R., Brown, J., Matsuoka, K., Witrant, E., Philippe, M., Hubbard, B., and Pattyn, F (2015) Anomalously-dense firn in an ice-shelf channel revealed by wide-angle radar, The Cryosphere Discuss., 9, 5647-5680, doi:10.5194/tcd-9-5647-2015.

Schwegmann, S., Rinne, E., Ricker, R., Hendricks, S., and Helm, V. (2015) About the consistency between Envisat and CryoSat-2 radar freeboard retrieval over Antarctic sea ice, The Cryosphere Discuss. 9, 4893-4923, doi:10.5194/tcd-9-4893-2015.

Publications archive:

The following list is a summary of literature on Antarctic sea ice that has presents results from ship-based sea ice observations. This includes papers and reports based on individual cruises, as well has those that have made use of the full ASPeCt data archive.

Ackley, S. F (1979), Mass-balance aspects of Weddell Sea pack ice, Journal of Glaciology, 24(90), 391-405.

Ackley, S. F., P. Wadhams, J. C. Comiso and A. P. Worby (2003), Decadal decrease of Antarctic sea ice extent inferred from whaling records revisited on the basis of historical and modern sea ice records, Polar Research, 22(1), 19-25.

Allison, I. (1989), The East Antarctic sea ice zone: ice characteristics and drift, GeoJournal, 18.1, 103-115.

Allison, I., R. E. Brandt, and S. G. Warren (1993), East Antarctic sea ice: albedo, thickness distribution and snow cover, Journal of Geophysical Research, 98, 12,417-12,429.

Allison, I. and A. P. Worby (1994), Seasonal changes of sea ice characteristics off East Antarctica, Annals of Glaciology, 20, 195-201.

Brandt, R. E., S. G. Warren, A. P. Worby, and T. C. Grenfell (2005), Surface albedo of the Antarctic sea ice zone, Journal of Climate, 18(17), 3606-3622.

Casarini, M. P., and R. Massom (1987), Winter Weddell Sea Project, Sea ice observations, leg 2: June-September 1986, University of Cambridge, Scott Polar Research Institute, Cambridge, UK, 161 pp.

DeLiberty, T.D., C.A. Geiger, S.F. Ackley, A.P. Worby, and M. VanWoert (2011), Estimating the annual cycle of sea ice thickness and volume in the Ross Sea, Deep Sea Research, 58 (9 — 10), 1250 — 1260, doi:10.1016/j.dsr2.2010.12.005.

Eicken, H., T. C. Grenfell, and B. Stonehouse (1988), Sea ice conditions during an early spring voyage in the eastern Weddell Sea, Antarctica, Polar Record, 24(149), 49-54.

Eicken, H., and M. A. Lange (1989), Development and properties of sea ice in the coastal regime of the Southeastern Weddell Sea, Journal of Geophysical Research, 94(C6), 8193-8206.

Haas, C., T. Viehoff, and H. Eicken (1992), Sea-ice conditions during the Winter Weddell Gyre Study (WWGS) 1992 ANTX/4 with RV “Polarstern”: Shipboard observations and AVHRR satellite imagery, Berichte aus dem Fachbereich Physik, 34, Alfred Wegener Institute für Polar und Meeresforschung.

Heil, P., R.A. Massom, I. Allison, A.P. Worby, and V.I. Lytle (2009), The role of off-shelf to on-shelf transitions of East Antarctic dynamics during spring 2003, Journal of Geophysical Research, 114, doi:10.1029/2008JC004873.

Heil, P., R.A. Massom, I. Allison, and A.P. Worby (2011), Physical attributes of sea-ice kinematics during spring 2007 off East Antarctica, Deep-Sea Research II, 58 (9 — 10), 1158 — 1171, doi:10.1016/j.dsr2.2010.12.004.

Hutchings, J.K., P. Heil, A. Steer, and W.D. Hibler III (2012), Small-scale spatial variability of sea ice deformation in the western Weddell Sea during early summer, Journal of Geophysical Research, 117, C01002, doi:10.1029/2011JC006961.

Jacka, T. H., I. Allison, and J. C. Wilson (1987), Characteristics of the seasonal sea ice of East Antarctica and comparisons with satellite observations, Annals of Glaciology, 9, 85-91.

Jeffries, M. O., K. Morris, T. Maksym, N. Kozlenko, and T. Tin, Autumn sea ice thickness, ridging and heat flux variability in and adjacent to Terra Nova Bay, Ross Sea, Antarctica, Journal of Geophysical Research, 106(C3), 4437-4448.

Jeffries, M. O., and W. F. Weeks (1992), Structural characteristics and development of sea ice in the western Ross Sea, Antarctic Science, 5(1), 63-75.

Jeffries, M. O., A. P. Worby, K. Morris, and W. F. Weeks (1997), Seasonal variations in the properties and structural composition of sea ice and snow cover in the Bellingshausen and Amundsen Seas, Antarctica, Journal of Glaciology, 43(143), 138-151.

Lytle, V. I., A. P. Worby, and R. Massom (1998), Sea ice pressure ridges in East Antarctica. Annals of Glaciology, 27, 449-454.

Nihashi, S., K. I. Ohshima, M. O. Jeffries, and T. Kawamura (2005), Sea-ice melting processes inferred from ice-upper ocean relationships in the Ross Sea, Antarctica, Journal of Geophysical Research, 110, C02002, doi:10.10

Ozsoy-Cicek, B., S.F. Ackley, A. Worby, H. Xie, and J. Lieser (2011), Antarctic sea-ice extents and concentrations: comparison of satellite and ship measurements from International Polar Year cruises, Annals of Glaciology, 52 (57), 318 — 326.

Ozsoy-Cicek, B., S. Kern, S.F. Ackley, H. Xie, and A.E. Tekeli (2011), Intercomparisons of Antarctic sea ice types from visual ship, RADARSAT-1 SAR, Envisat ASAR, QuikSCAT, and AMSR-E satellite observations in the Bellingshausen Sea, Deep-Sea Research II, 58 (9 — 10), 1092 — 1111, doi:10.1016/j.dsr2.2010.10.031.

Steer, A., A.P. Worby, and P. Heil (2008), Observed changes in sea ice floe size distribution during early summer in the western Weddell Sea, Deep-Sea Research II, 55 (8–9), 933–942.

Timmermann, R., A. P. Worby, H. Goosse, and T. Fichefet (2004), Utilizing the ASPeCt sea ice thickness data set to evaluate a global coupled sea ice ocean model, Journal of Geophysical Research, 109, C07017, doi:10.1029/2003JC002242.

Tin, T. and M. O. Jeffries, M. Lensu, and J. Tuhkuri (2003), Estimating the thickness of ridged sea ice from ship observations in the Ross Sea, Antarctica, Antarctic Science, 15(1), 47-54.

Tin, T., R. Timmermann, and M. O. Jeffries (2004), A field and numerical study of the evolution of sea ice thickness in the Ross Sea, Antarctica, 1998-99, Journal of Glaciology, 50(170), 436-446.

Vancoppenolle, M., R. Timmermann, S.F. Ackley, T. Fichefet, H. Goosse, P. Heil, J. Lieser, K.C. Leonard, M. Nicolaus, T. Papakyriakou, J.-L. Tison (2011), Assessment of radiation forcing data sets for large-scale sea ice models in the Southern Ocean, 23pp., Deep-Sea Research II, doi:10.1016/j.dsr2.2010.10.039.

Wadhams, P., M. A. Lange, and S. F. Ackley (1987), The ice thickness distribution across the Atlantic sector of the Antarctic Ocean in midwinter, Journal of Geophysical Research, 92(C13), 14,535-14,552.

Worby, A. P., M. O. Jeffries, W. F. Weeks, K. Morris, and R. Jaña (1996), The thickness distribution of sea ice and snow cover during late winter in the Bellingshausen and Amundsen Seas, Antarctica. Journal of Geophysical Research, 101(C12), 28,441-28,455.

Worby, A. P., R. A. Massom, I. Allison, V. I. Lytle, and P. Heil (1998), East Antarctic sea ice: a review of its structure, properties and drift. In: Antarctic Sea Ice Properties, Processes and Variability, edited by M. O. Jeffries, AGU Antarctic Research Series, 41-67.

Worby, A.P., A. Steer, J. Lieser, P. Heil, D. Yi, T. Markus, I. Allison, R.A. Massom, N. Galin, and J. Zwally (2011), Regional-scale sea ice and snow thickness distributions from in situ and satellite measurements over East Antarctica during SIPEX, Deep-Sea Research II, 58, 1125 — 1136, doi:10.1016/j.dsr2.2010.12.001.

Worby, A. P., and X. Wu (1998), East Antarctic sea ice: observations and modelling. Annals of Glaciology, 27, 427-432.

Worby, A. P. (1999), Observing Antarctic Sea Ice: A practical guide for conducting sea ice observations from vessels operating in the Antarctic pack ice. A CD-ROM produced for the Antarctic Sea Ice Processes and Climate (ASPeCt) program of the Scientific Committee for Antarctic Research (SCAR) Global Change (GLOCHANT) program, Hobart, Tasmania, Australia.

Worby, A. P. and I. Allison (1999), A technique for making ship-based observations of Antarctic sea ice thickness and characteristics, Part I: Observational technique and results, Antarctic CRC Research Report, 14, pp 1-23.

Worby, A. P. and V. Dirita (1999), A technique for making ship-based observations of Antarctic sea ice thickness and characteristics, Part II: User operating manual, Antarctic CRC Research Report, 14, pp 24-63.

Worby, A. P. and S. F. Ackley (2000), Antarctic research yields circumpolar sea ice thickness data. Eos, Transactions of American Geophysical Union, 81(17), 181, 184-185.

Worby, A. P. and J. C. Comiso (2004), Studies of the Antarctic sea ice edge and ice extent from satellite and ship observations, Remote Sensing of Environment, 92, 98-111.

Data

Links