Meteorology and Ozone Monitoring

Meteorological observations are made regularly throughout the day at Halley and Rothera. Surface temperature, humidity, sunshine, pressure, wind speed and direction are largely measured by automated instruments but an observer is needed to estimate the visibility and the amount, type and height of clouds, although automatic instruments are being introduced. The observer also needs to keep note of the weather: rain, snow, fog, gale etc. as well as more unusual phenomena: diamond dust, halos, mirages and the aurora australis.

All the observations are expressed in a numeric code and sent via geostationary satellites to meteorological centres, where they join thousands of other observations from all over the world. The real-time data are processed by super-computers and used to forecast the weather and are archived and used for further climatic research.

Radiosondes

Data from these radiosondes are used in computer models to give the latest weather forecasts and are used for climate research. Recent studies of the data from Halley and several other Antarctic stations have shown there to be a significant warming of the mid-troposphere in the wintertime during the last 30 years.

Stratospheric ozone monitoring

Stratospheric ozone is measured at Halley and Rothera research stations. Ozone measurements, from Halley research station, that have been recorded since the International Geophysical year (IGY) in 1957/8, led to the discovery of the hole in the ozone layer in 1985.

Stratospheric ozone shields the earth’s surface from more than 90 % of harmful solar ultraviolet radiation. The “ozone hole” was discovered in 1985 by BAS scientists using Halley’s unique data set of Dobson spectrophotometer observations which now spans 60 years. Maintaining these observations, at Halley and elsewhere, is crucial to monitoring the slow recovery of stratospheric ozone following the banning of CFCs.

The destruction of ozone by CFCs in the stratosphere requires extremely cold temperatures, and energy from sunlight. Antarctic ozone therefore begins to decrease in the spring with the end of polar night, and recovers during the dark winter months when ozone is replenished by atmospheric mixing. Halley is well positioned to study the ozone hole: springtime sunlight returns early enough to allow Dobson measurements during ozone depletion, and atmospheric circulation patterns place minimum concentrations above the station. This year, with the future safety of the Brunt Ice Shelf uncertain, a second Dobson spectrophotometer will be set up to make observations without a human operator, and the newer automated ozone spectrometer adapted to run independently of station power.

The discovery of the ozone hole provides a prime example of the importance of investing in long-term observational science.