Halley Research Station

A station for a geophysical year

The Royal Society established the station on the Brunt Ice Shelf on 15 January 1956 for the International Geophysical Year of 1957–58. It is named for Halley Bay, itself named after the astronomer Edmond Halley. The ice shelf flows towards the sea, so each station has to be replaced as its site is buried and moves; Halley VI is the sixth.

From the first year the station took Dobson spectrophotometer readings, measuring the total amount of ozone in the column of air above it by comparing the ultraviolet light of the sun at two wavelengths.

The ozone hole

In 1985 Joe Farman, Brian Gardiner and Jonathan Shanklin of the British Antarctic Survey published, in Nature, the finding that spring ozone over Halley had fallen by about a third since the 1970s. The depletion was soon linked to chlorine from chlorofluorocarbons, leading to the Montreal Protocol of 1987.

Satellite instruments had also seen low values over Antarctica, but the software used to process them had flagged such values as probable errors. The ground-based record, taken with a simple calibrated instrument for decades, was the one that was trusted.

Halley VI and the move

Halley VI, opened in February 2013, is made up of modules on hydraulic legs and skis that can be jacked up above the snow and towed to a new site. In 2016–17 a crack in the ice shelf prompted the station to be relocated 23 kilometres inland, and winter staffing was paused. It remains a base for atmospheric and space-weather monitoring, with instruments operated remotely through the winter.

Living on a moving ice shelf

Each station at Halley has been replaced as the ice shelf moved and buried it: the first stations were crushed by snow and the later ones carried away as the ice flowed to the sea. Halley VI was designed to avoid that fate, with legs that climb and skis that tow. Even so, in 2016 a new crack in the ice, the Halloween Crack, forced a move of the whole station, and winter staffing was suspended while the new site was prepared. A station on a moving ice shelf is a long-term experiment in engineering as much as in science, and its record of ozone is the product of that continued effort.

Instruments and technologies

• Dobson spectrophotometer A double-prism spectrograph that compares the intensity of sun or moon light at wavelengths strongly and weakly absorbed by ozone, to give the total ozone column.
• Halley VI modules Eight steel modules on hydraulic legs with ski feet, so that the station can be raised above drifting snow and moved.
• Atmospheric and space-weather instruments Magnetometers, riometers and other geospace instruments operate at the station, with part of the programme remote-controlled.

The people

• Joe Farman British Antarctic Survey scientist; co-discoverer of the ozone hole.
• Brian Gardiner Co-discoverer; made the measurements.
• Jonathan Shanklin Co-discoverer; analysed the record.

Timeline

• 1956 Station established on 15 January for the International Geophysical Year.
• 1985 Farman, Gardiner and Shanklin publish the ozone hole discovery in Nature.
• 2013 Halley VI opens in February.
• 2017 Station relocated 23 km inland after an ice crack (2016–2017); winter staffing paused.

Key lessons for observation today

• Trust the calibrated long record A simple instrument with decades of calibration caught what automatic screening discarded. Automatic quality control must keep the raw data and explain its flags.
• Design for a moving site Halley VI can be towed. When the environment moves, the station should be able to move with it.
• Remote operation extends coverage Instruments that run unattended keep the record through the winter. Remote-operable sensors are the model for polar networks.

Sources

• British Antarctic Survey, The ozone hole discovery
• British Antarctic Survey, Dobson Spectrophotometer (Halley)
• Wikipedia, Halley Research Station
• Wikipedia, Joseph Farman