Science on an ice shelf – working in Antarctica
Dr Amy Valach, who recently finished a PhD in Environmental Science at Lancaster University, writes about her work as a research scientist at the Halley Research Station. Earlier this year she featured on a BBC Horizon programme about Halley, called “Ice Station”.
I recently finished a PhD in Atmospheric Sciences at Lancaster University and was given the opportunity of a lifetime to work for the British Antarctic Survey at the Halley Research Station in Antarctica. A daunting task considering this is my first job as a qualified scientist!
Halley was founded in 1956 and has been an important location for science ever since. There are continuous records for all sorts of observations that are vital in understanding a number of natural and manmade phenomena worldwide.
Significant discoveries, such as the ozone hole and processes linking the solar wind energy with Earth’s upper atmosphere, have been made using data gathered here.
Halley VI
The current station, Halley VI, focuses on understanding the polar atmosphere, its chemistry and dynamics, as well as the vertical coupling through the whole atmosphere including how solar variability affects climate.
The location of Halley, at 75° 36’ S 26° 14’ W, makes it an ideal place to study everything from the lowest layer of the atmosphere, the troposphere where the weather happens, all the way up to the outer layers where space weather takes place.
Monitoring the weather – sensors, readers and balloons
The bread and butter of my job here is to maintain the long-term meteorological records. I use a range of technical instruments to do this, such as a laser precipitation sensor to measure snow fall, a cloud base reader showing the height of the lowest clouds and a range of anemometers to measure wind speed and direction. But some things still cannot be measured electronically and need a trained eye to observe them.
Every day we launch weather balloons carrying equipment that measures temperature, humidity, pressure and GPS coordinates. These measurements allow us to calculate wind speed and direction, providing one of the very few data points in Antarctica.
These data feed into daily weather forecasts, but also the long-term trends are used to monitor changes in temperature at different heights within the atmosphere.
How the world is warming
Records show that the atmosphere has warmed below 8 km and cooled above this height over the past 30 years. This is due to increases in greenhouse gases and is observed globally.
However, the warming seen at 5 km above Halley in winter is over three times the global average rate at this level. Although no warming has been measured at the surface at Halley, there have been significant changes in temperature higher up and elsewhere on the continent.
Understanding natural processes and detecting distant pollution
The pristine air coming off the Antarctic continent allows us to make background readings of the chemistry when there is no local pollution, which helps us understand a variety of natural processes, such as the formation of ice clouds and natural ground level ozone cycling due to sea ice processes.
Due to the lack of pollution here we can detect small changes in the atmospheric composition including particulates from distant forest fires or volcanic eruptions, changes in greenhouse gases and the distribution of pollutants from fossil fuel use around the world.
Recent findings have shown that the Southern Ocean may be becoming less efficient at taking up carbon dioxide (CO2) over the past decades due to increasing winds and resulting changes in ocean currents.
As Halley lies on the Brunt ice shelf near to the Weddell Sea it is the perfect place to measure air-sea interactions. This summer a new instrument was installed to help measure short-term fluctuations in oxygen, which acts as a proxy for variations in air-sea CO2 levels.
The Ozone layer – a slow recovery
A vintage piece of equipment called the Dobson spectrophotometer that led to the discovery of the ozone hole in 1985 is still used today to measure the total amount of ozone in the atmosphere. In the 1970s the use of CFCs (chlorine-containing compounds) caused a dramatic depletion in the ozone layer, which is now starting to stabilise, but will take many decades to recover.
The destruction happens during the Antarctic spring when the conditions are right for a rapid reduction of ozone. When the sun returns in August it catalyses chemical reactions involving chlorine-containing compounds associated with so-called polar stratospheric clouds, which are located at the same height as the ozone layer and need very cold conditions to form (below -78 °C). During the rest of the year the ozone layer recovers, but it will take decades before the dip in springtime disappears.
We also have a range of radars and magnetometers at Halley to study space weather, which the engineers maintain.
The Halley site is a large area dotted with antennas and containers housing a range of gadgets, and also includes all the infrastructure to maintain the station and the 13 people who stay here the year round.
An Antarctic winter
The summer season ended at the beginning of March when the sea ice starts to become too thick for the ship to reach the ice shelf. For the following few months we enjoyed the most stunning sun rises and sets until the end of April when the sun set for the last time – heralding the start of the polar winter, which has its own beauty.
When the sky is clear there is a soft orange glow on the northeast horizon around midday, but during the rest of the time the darkness encompasses the station with a blanket of a million stars.
Author biography
Dr Amy Valach is an atmospheric scientist working for the British Antarctic Survey. She has a PhD in Environmental Sciences and an Ecology degree from Lancaster University. Her area of research interest is to understand the effects of surface exchanges to the atmosphere in the Earth system.
