IC Scientific Programme 1995

Ice Climate and Global Change

Past climate and environment

A bilateral UK/German drilling programme on Berkner Island will collect medium depth ice cores from the north and south domes and shallower cores. A 150 m long core from the north dome should provide 700 years of accumulation , while a 300 m core on the south dome should extend back 1700 years.

In the UK, laboratory studies on ice cores will continue to establish a high resolution time series of climate during the past several hundred to a few thousand years in the Antarctic Peninsula region. Ice cores from Beethoven Peninsula and Gomez Nunatak will be examined, particularly their isotopic composition, anions and MSA on appropriate sections. A new electromechanical ice core drill and associated control systems will be built and commissioned for use on Berkner Island.

Chemistry and physics of Antarctic ice

An automatic air sampler for recovering aerosols will be installed at Halley Research Station. The sampler collects a year's sequence of 15-day aerosol samples, in order to compare the record with that in the snowfall deposited during the same periods.

Studies of the conductivity of ice at DC and up to 100 kHz will be made on the ice core as it is drilled on Berkner Island.

In the UK, aerosol samples collected at Halley Research Station in 1991 will be analysed and interpreted. A comparison will be made of the electrical and radar data from the Greenland Ice Core Project core will be made; two sequences of GRIP ice will be analysed for high resolution chemistry and subjected to analysis by a scanning electron microscope. Studies will continue on the relationship of the chemistry of the atmosphere to the chemistry of snowfall and its subsequent metamorphosis on the ground.

Impact on sea level of the ice sheet in the Antarctic Peninsula

Ice temperatures at 10 m depth and shallow ice cores will be collected on a traverse from the Behrendt Mountains through to the upper regions of the Evans Ice Stream and Rutford Ice Stream. Some of the sites were visited in 1961.

A mass and energy budget study on the Uranus Glacier will include detailed ground measurements linked to satellite data and upper air data.

In the UK, a synthesis of data will provide predictions of the Antarctic Peninsula ice sheet contribution to future sea level rise.

Applied glaciology

Monitoring will continue of the deposition of snow around the station buildings at Halley and the differential deformation of the ice around the legs of the platforms housing the station buildings.

Ice strain rosettes, set up in 1993-94 up to 120 km from Halley Research Station, will be resurveyed in a study of the deformation of the Brunt Ice Shelf.

In the UK, survey data will be analysed to assess the dynamics of the Brunt Ice Shelf near Halley Station in order to predict its future behaviour.

Ice sheet dynamics

Field work will be carried out on Evans and Rutford ice streams contributing to the study of ice streams which drain into Ronne Ice Shelf. Ice velocities will be measured on Evans Ice Stream using GPS and reflectors emplaced for use in SAR interferometry. Networks installed in 1993-94 across the upper end of Rutford Ice Stream will be resurveyed and temperature data collected from thermistor strings in the shear zone.

In the UK, theoretical studies will continue to further understanding of the present and past behaviour of the Antarctic ice sheet in order to make reliable predictions of its future behaviour. In particular an evolutionary model of the Filchner-Ronne Ice Shelf will be applied to study the implications of various basal melting regimes to the mass balance of the ice sheet. Active support of the European Ice Sheet Modelling Initiative (EISMINT) will continue.

Remote sensing of ice

Twenty hours of airborne ice depth sounding will investigate internal layering in the ice sheet along the plateau of Palmer Land, the onset of streaming flow at the head of the Rutford Ice Stream, the extent and thickness of basal marine ice at sites on the Ronne Ice Shelf, and provide a thickness transect in support of GPS ice velocity studies around the Evans Ice Stream.

In the UK, satellite data will be employed to register and monitor changes in extent and movement of the Antarctic ice sheet. Processing and analysis of seismic reflection and wide angle data from Rutford Ice Stream will continue. The BAS radioecho sounder will be upgraded to include a chirp option.

Thermal regime of ice shelves

Ice thickness, gravity data and sea floor depth data will be collected on Ronne Ice Shelf in a region where none exists along a traverse from 81 55'S, 50 20'W, south of Berkner Island, south of Henry and Korff ice rises, and north towards the flowline of Evans Ice Stream. A strain rosette will be remeasured at a previous study area (Site 3: 78 44'S, 71 46'W).

In the UK, theoretical studies will further understanding of the present-day thermal structure of ice shelves which is dictated by surface climate, ice flow and deformation, and heat and mass exchange with the underlying ocean. In particular a tidal model will be applied to Ronne-Filchner Ice Shelf and thermistor cable data from the water column beneath Sites 1 and 2 on Ronne Ice Shelf interpreted.

Dynamical and physical climatology

Observing programmes at Halley, Faraday, Signy and Rothera will continue. An Automatic Weather Station will be installed at Faraday in January 1995.

An upper-air programme will be implemented from RRS Bransfield using a micro CORA radiosonde system.

Automatic Weather Stations owned by University of Wisconsin will be serviced to enhance the coverage of meteorological data from the Antarctic Peninsula.

In the UK, the present climate regime of the Antarctic will be studied together with the mechanisms which control the Antarctic climate.

Dynamics of the stable boundary layer

Instrumentation will be installed at Halley Research Station for routine measurement of the surface energy and water balance.

In the UK, theoretical studies will improve the mesoscale modelling of the atmospheric boundary layer for use in weather forecasting and climate models. Instruments will be developed for boundary layer profiling.

Synoptic and mesoscale atmospheric processes

Routine collection and processing of data will continue from the Antarctic Reception of Imagery for Environmental Studies (ARIES) satellite system.

Equipment to make in situ measurements of cloud and precipitation properties will be tested at Rothera Research Station.

In the UK, high latitude meteorological processes will be studied using satellite data to determine their role in the general circulation of the atmosphere. In particular a new physical algorithm for retrieving precipitation from passive microwave imagery will be developed further, and case studies carried out of weather systems crossing the Antarctic Peninsula using model fields and satellite observations.

Satellite climatology

In the UK, the climatology of high latitude weather systems will be studied using satellite remote sensing data, in particular, the interannual variability of precipitation, the variability of cyclogenesis and the effects of weather systems on sea ice extent and concentration.

Stratospheric chemistry and dynamics

Measurements of total ozone at Halley and Faraday research stations will continue.

A UV-visible spectrometer will be installed at Halley Research Station able to make stratospheric measurements of ozone and ozone-related gases during the winter and early spring using absorption spectra from the moon and stars.

In the UK, modelling studies will allow the implications of ozone depletion to be assessed for regions outside the Antarctic. Laboratory measurements will investigate slit function and angular response characteristics of ultraviolet radiometers to be deployed in an Arctic field campaign in 1995.