— Katie Joy | 18 Dec 2019
We have written several posts about Halley research station, our home-from-home research base for the past two Antarctic field seasons — but what other science is being supported from Halley?
The station, located on the Brunt Ice Shelf at Lat. 75°34’5″S, Long. 25°30’30″W, has been occupied as a British base since 1957. The current version is called Halley VI and, with its futuristic space-station looking red and blue modules, is currently home to about 35 people in the summer who are supporting the station infrastructure and are assisting in the long-term science experiments running out of the station. Currently, because of potential issues surrounding the possible breakup of the Brunt Ice Shelf (see news stories here and here) the station is being operated in summer crew mode, and in the winter (from February onwards) all the staff leave Antarctica and return to the UK.
Current Science projects
Ozone hole monitoring: Measurements made at Halley that led to the discovery of a hole in the ozone layer in the 1980’s, leading to banning of CFC chemicals and international concern about the effects of ozone loss in the stratosphere (middle atmosphere). The equipment that made the discovery is still in use at Halley VI: called a Dobson spectrophotometer, is a device for measuring the amount of different wavelengths of ultraviolet (UV) radiation that reaches the ground (read more here) and used to determine ozone column density above our heads. Antarctica is a great place to make these measurements as there are few atmospheric pollutants which might absorb the specific wavelengths of light being measured. The station has a manual version of the spectrometer (see photo), a separate ozone monitoring station, and also recently has installed a computerised Dobson spectrometer that can run in automated mode through the Antarctic sunset and sunrise around winter when the base is without a crew. This automation has been made possible by the introduction of a micro-turbine energy generator, which ensures that this 60 year experiment can continue to run and collect data to ensure scientists with a continuous record of Antarctic ozone layer variation.
Climate change monitoring, atmospheric and daily weather observations: Understanding how the climate is changing through time is a key science priority for the British Antarctic Survey. Every day the researchers here launch a weather balloon to measure the temperature of the atmospheric column, a record going back over 30 years which suggests that the atmosphere has been warming year on year up to 8 km in height above the ice surface. Scientists also measure the chemistry (trace gases and aerosol) of the Antarctic air using a special clean air sector laboratory (the lab is located in a position where aircraft cannot fly above it and no one can drive a mechanical vehicle like a skidoo in its vicinity — as such people Nordic ski or hike out to visit the site). Other atmospheric monitoring experiments to understand global high altitude wind (gravity wave) propagation, lightning strikes, and high altitude (87 km) temperature measurements all complete a suite of instruments that are setup or are being set up to run automated throughout the Antarctic summer and winter seasons to understand Earth’s atmosphere. In addition to these high altitude and long term climate records, daily weather (temperature, dewpoint, wind speed, cloud coverage, cloud type) is recorded and is also used for helping out logistical planning for aircraft movement around the area.
Space weather observations: Space weather is the term used when energetic particles ejected from the Sun interact with the Earth’s protective magnetic field (known as its magnetosphere). Often this interaction manifests itself as aurora at the northern and southern poles (also known as the southern and northern lights). An all-sky optical camera and, in the future, a new camera system will be able to monitor changes in local aurora conditions at Halley to determine the effects of ionisation in the upper atmosphere. This ionisation can also alter Earth’s magnetic field itself, and a series of magnetometers run at Halley to monitor these changes. Together this knowledge helps to understand the potential electromagnetic risks to orbiting satellites and on Earth electrical-based infrastructure, as well as helping unravel the fundamental science of how the Earth interacts with its space environment.
Brunt Ice Shelf movement: The ice under our feet at Halley is about 150 m thick. The station is slowly drifting towards the Weddell sea as the Ice Shelf propagates off the continent heading in a north-westerly direction. The Brunt Ice Shelf is continually in a cycle of growth and then break-up when large parts of the Ice Shelf edge carve and break off into the sea. At the moment there are two very large cracks opening up to the north (the Hallowe’en crack) and to the west (Chasm 1 crack) of the station. The development of these cracks and the movement of the Brunt Ice Shelf is being carefully monitored using high spatial resolution GPS stations and radar stations that are distributed around several sites on the Brunt. As and when, the Chasm 1 crack finally breaks the Ice Shelf in two, BAS will be a unique position to monitor the carving event and watch how the remaining Brunt Ice Shelf under Halley station responds to the change.