Research Overviews

Sea Ice and Polar Oceanography Group

Dr P. Wadhams

Dr N.R. Davis, E. Aldworth, S. Wells, J. Wilkinson
Y.Aksenov, M. Brandon, F. Cottier, M. Huddleston, I. Jonsdottir,
D. Low, M. Tadross, Capt L. Brigham, M. Aitchison, F. Boud

The Sea Ice and Polar Oceanography Group continued to work on four European Commission research projects, one project funded by the US Office of Naval Research, and two projects funded by NERC.

The main field programme during the year was a voyage by HM submarine Trafalgar to the Eurasian Basin of the Arctic Ocean and the Greenland Sea in August-September 1996. Dr Peter Wadhams sailed aboard the submarine and collected systematic data on ice draft, ice bottom topography (via sidescan sonar), and ocean temperature and salinity along some 5000 km of under-ice track.

The largest research project was the European Subpolar Ocean Programme (ESOP), funded by the EU under the MAST-II initiative, with Dr Wadhams as coordinator. The project involves 22 institutions from seven European countries, and is the fourth largest project in MAST-II. Its aim is to understand sea ice-ocean interactions in the Greenland Sea, in particular the processes that underlie winter convection and the thermohaline circulation. The effect of convection on the carbon cycle also forms an important part of the project. During the year, the Institute was represented at the MAST Days and EUROMAR Market symposium in Sorrento, Italy, in November 1995, and on 24-26 April 1996 Dr Wadhams held a Final Symposium for the project at the Institute. In connection with the results of this project, which show that deep convection has ceased in the Greenland Sea under the effects of global warming, Dr Wadhams made several television and radio appearances during spring 1996, accompanied by a number of newspaper articles in the British, European, and US press. The final project science report, with 600 pages and 29 chapters by the participating scientists, was published in July 1996 and will be republished in abridged form as a special issue of Journal of Marine Systems.

The project extended until December 1996, but overlapping it is ESOP-2, a successor programme under MAST-III, which began in February 1996 and in which Dr Wadhams is a principal investigator. This continues the work of ESOP for three more years, focusing on the oceanography of the thermohaline circulation. Dr Wadhams is on the Steering Committee of the project and attended meetings in Copenhagen in January 1996 and Voss (Norway) in March 1996.

Dr Wadhams has also been principal investigator of an EU research project in the Environment and Climate Programme, shared with IMGA-CNR in Modena (Dr Flavio Parmiggiani). The purpose is to measure the thickness of frazil and pancake ice in the Greenland Sea by analysing the change in the wavelength and direction of ocean waves as they enter the ice. This involves the spectral analysis of synthetic aperture radar (SAR) imagery from the ERS-1 and ERS-2 satellites. Again, Dr Wadhams held a symposium at SPRI on the project on 2 May 1996, attended by Professor Klaus Hasselmann of the Max Planck Institut für Meteorologie, Hamburg, originator of the SAR wave spectrum algorithm. This project also continues until December 1996.

The fourth EC programme is another new one under MAST-III, which began in February 1996 for three years. It is called 'Ice State,' co-ordinated by Helsinki University of Technology (Professor Kaj Riska) with Dr Wadhams as a principal investigator, and it seeks to understand the relationship between sea ice mechanical processes and the resistance offered by an ice sheet to ship passage. Dr Wadhams attended the opening meeting in Helsinki in January 1996. The first science meeting of the project was hosted by Dr Wadhams at SPRI on 6-7 June 1996.

The two NERC projects were both completed in 1995-96. They concerned light penetration through sea ice and its influence on the average light availability in the marginal ice zone (MIZ), a quantity of great importance for determining the onset of the spring plankton bloom. The final work on the project comprised the construction of a model for irradiance in the MIZ, based on our field results from Antarctica and Alaska of light penetration through ice, and knowledge of ice dynamics, concentrations, and floe sizes in the MIZ. The larger of the two grants was a BAS Special Topic project carried out jointly with Dr Julian Priddle of the British Antarctic Survey.

The ONR project concerns interpretation of data gathered in 1994-95 on the SIMI programme (Sea Ice Mechanics Initiative), an ice camp in the Beaufort Sea north of Alaska in which SPRI measured ice tilt, heave, strain, and accelerations in conjunction with other groups measuring stress and ice dynamical parameters. The interpretation includes the role of ridge-building in generating wave activity, and the flexural repsonse of the ice sheet to the tidal cycle. Dr Wadhams attended a workshop on the project in Seattle in April 1996.

New projects in hand included being a partner in the experimental programme of the European Ice Tank, established as an EU Large Facility at the Hamburgische Schiffbau-Versuchsanstalt GmbH (HSVA). Dr Wadhams attended the planning meeting for the first phase of the project in Bremerhaven on 16-17 June 1996, in which a programme was designed to begin in November, which will include SPRI work on brine drainage channels and pancake ice.

During the year Mark Brandon (Research Student) completed a PhD thesis entitled 'Winter surface water mass modification in the Greenland Sea,' and Douglas Low (Research Student) completed an MSc thesis on 'The validation of ERS-1 SAR data for Antarctic summer sea ice' for the University of Dundee, supervised by Dr Wadhams. Finlo Cottier (Research Student) joined the group in October 1995 to work on brine drainage channels in sea ice; and Yevgeny Aksenov (Research Student) joined the group in April 1996 to work on the Ice State project, having formerly been a research scientist at the Arctic and Antarctic Research Institute, St Petersburg. Matt Huddleston (Research Student) continued with a PhD project on an ice-ocean numerical model for the Arctic Ocean and Greenland Sea, Mark Tadross (Research Student) on the remote sensing of young ice in the Odden ice tongue, and Ingibjorg Jonsdottir (Research Student) on the statistics of sea-ice distribution around Iceland.

Dr Wadhams, the Reader in Polar Studies, spent October-December 1995 as Visiting Professor at the Arctic Environmental Research Centre, National Institute of Polar Research (NIPR), Tokyo, Japan. During this period he attended the INSROP (International Northern Sea Route Project) Symposium in Tokyo on 1-6 October, giving an invited presentation; the International GCOS symposium (Global Climate Observing System) in Tokyo, October 20; and was an invited speaker at the Wadati Conference on Global Change and the Polar Climate in Tsukuba Science City, 7-10 November. He began joint work with NIPR on the interpretation of Japanese ERS satellite imagery, as project 38 of the newly-signed NERC-Japan agreement on collaboration in remote sensing.

In January 1996 Dr Wadhams was appointed associate editor of the Journal of Physical Oceanography. He was a member of the organizing committee and was convenor of the Polar Oceans Session, for the Oceanology '96 conference and exhibition at Brighton in March 1996. He gave a paper at the session, as did Matt Huddleston (Research Student) and Lawson Brigham (MPhil Student).

Dr Wadhams attended planning meetings on the Arctic Ocean Grand Challenge (a 10-year European Science Foundation programme) in Bergen in January 1996, and at SPRI on a NERC Arctic Initiative on 22 April 1996. He visited ESOP laboratories in Germany and Denmark during March 1996, and visited NASA Goddard Space Flight Center, Greenbelt, Maryland, in May 1996 to work on joint papers with Dr J.C. Comiso. During the last visit he was appointed to the Science Committee of AEGIR (Advanced ESSP Global Ice Radar), a NASA planning group for a new satellite radar altimeter.

With support from the B.B. Roberts Fund, Dr Wadhams hosted a visit to SPRI on 1-4 June 1996 by Dr Ivan Frolov and Dr Sergei Pryamikov, repectively Director and Head of International Relations at the Arctic and Antarctic Research Institute, St Petersburg, which also celebrated its seventy-fifth birthday in 1995. He took the visitors on to the conference of the International Arctic Buoy Programme in Bracknell (4-5 June), where Dr Wadhams gave an invited lecture.

Dr Wadhams hosted a meeting of the International Programme for Antarctic buoys (IPAB) at SPRI on 1-3 August 1996, dealing with the further development of international collaboration in the positioning of Argos ice drifters on Antarctic sea ice and the pooling of data received.