N.Z. instrument for Ice

Press, 28 December 1987, Page 6

N.Z. instrument for Ice

PA Wellington An instrument for measuring ozone is being shipped to Scott Base next month to help keep a close eye on the growing ozone hole over Antarctica. A Wellington meteorologist, Ms Sylvia Nichol, who will oversee the project for the Meteorological Service, will take a Dobson spectrophotometer, formerly sited at Invercargill, to the Antarctic in mid-January. The instrument is similar to one used by British scientists who first discovered in the early 1980 s the phenomenon of the springtime hole in the ozone layer over the Antarctic. Ms Nichol said the

Meteorological Office decided to send the spectrophotometer to the Antarctic when the Department of Scientific and Industrial Research atmospheric science post at Lauder in Central Otago obtained a similar instrument from the National Oceanic and Atmospheric Administration in the United States. As Lauder and Invercargill are not much more than 100 km apart, it was decided more value would be obtained by having the instrument where the ozone hole could be observed. Ms Nichol said American scientists who carried out much of their research on ozone from McMurdo Sound en-

couraged the move because they did not have a spectrophotometer available. The only instruments in the Antarctic are one at the United States South Pole base, and two others on the opposite side of the continent from the Ross Sea. One of these is run by the British at Halley Bay where the ozone hole phenomenon was first noted, and the other at a nearby Japanese base. To keep continuity of data for New Zealand records, the two instruments have been carefully compared during nine months of parallel work this year. Ms Nichol said that by doing some "statistical tricks,” the Invercargill

and Lauder data would provide a continuous record of ozone levels. The Lauder instrument, however, was better adapted to recording nitrous oxide. Measurements with the Dobson spectrophotometer can only be done at sunrise and sunset because of the need to get the right angles for measurement. In the Antarctic, sunrises and sunsets occur only in spring and autumn, with the sun above the horizon all the time in summer and below in winter. The spring observational season also overlaps with the occurrence of the ozone hole in September and October.

Ms Nichol said she would be flying to the Antarctic in late August to carry out intensive studies of the vertical distribution of the ozone layer as the hole developed. She will join a technician, Mr Dave Barrett, who will be wintering over to carry out observations. The instrument is capable of winter ozone observations using bright moonlight These are particularly useful because satellites cannot record ozone levels during the dark winter months. Ms Nichol and a senior meteorologist, Mr Tom Clarkson, will be leaving about January 13 to set up the instrument at Arrival Heights near Scott Base.