Lauder scientists are helping predict the spread and movement of volcanic ash, blown 10,000km around the world.
Ash caused by eruptions at Chile's Puyehue-Cordon Caulle volcano is being measured as it passes over the National Institute of Water and Atmospheric Research station at Lauder.
The usually clear blue skies above the station were cloudy on Saturday and Sunday as volcanic ash reached Central Otago. Equipment at Lauder measured the height of the cloud and its composition, with the data being sent to an international consortium. That consortium, in turn, passed on the information to various agencies, including aviation authorities, Niwa atmospheric scientist Ben Liley said.
"There's lots of monitoring in the northern hemisphere, but ours is pretty much it in the southern hemisphere, so our information confirmed the predictions as to when and where the volcanic ash would reach New Zealand, and what height it would be," he said.
"We are 10,000km downwind, but it's swirled and twisted its way over here and we've seen bits and pieces and measured it as it's passed over Lauder."
Mr Liley said the clear skies at the Central Otago location were ideal for recording data.
"Although it's gone at the moment [above Lauder], we could get the ash cloud swirling around New Zealand for a day or two, so we'll continue to watch and monitor."
The first plume of ash over Central Otago was about 2km wide and appeared at between 8.5km and 10km in altitude. The second layer, early on Sunday, was up about 9km but varied throughout the day.
The ash clouds are measured using a light detection and ranging (LIDAR) instrument, which shoots a laser beam upwards and measures how much light is scattered back off the small particles and clouds.
"The ash arrived here later on Friday and the weather was kind to us. It cleared up nicely, so we could use the LIDAR and measure [the cloud's] profile.
