Over The Horizon

How is the Air Up There?

This year's ozone hole over Antarctica has developed very rapidly from early September, and is of similar size and intensity as the record holes of the last three years, say researchers from NIWA, the National Institute of Water and Atmospheric Research.

Satellite data reveal a circular area of very low ozone concentration, 25 million km² in extent, covering the Antarctic continent. Readings at the centre of the hole are about 115 Dobson units, similar to last year's minimum and 60% lower than pre-1980 levels.

NIWA scientist Gordon Brailsford recently undertook a flight by Starlifter to collect air samples for later chemical and isotopic analysis. He is studying the composition of air in the lower stratosphere, in particular carbon dioxide, carbon monoxide, methane and ozone.

"Flights in early October are of special interest because the ozone hole is at its most intense, and the relationships of the trace gases are revealing new insights into the chemistry of ozone depletion", he says.