Dannevirke: Wind study helps forecast-accuracy

Growing up on a farm east of Dannevirke, Bill Brown always kept an eye on the weather.

Now the former Dannevirke High School pupil studies the weather and the atmosphere which affects it, as a scientist at the National Centre for Atmospheric Research (NCAR) in Boulder, Colorado where he's worked for 16 years as a project scientist and group leader of the earth observing laboratory.

His latest international weather research project has brought him home to New Zealand as his group of 12 take part in the Deepwave project in Hokitika.

Dr Brown's group is part of a larger group of scientists from five countries taking part in one of the biggest ever scientific experiments in New Zealand, aiming to significantly improve global weather forecasts.

"We're studying the phenomenon of westerly wind flows into the upper atmosphere," he said.

"My group are running a balloon site at Hokitika Airport looking at winds coming off the ocean and hitting the mountains, creating gravity waves in the atmosphere."

Gravity waves have a strong effect on the weather and occur when wind is disturbed by an obstructing landform, sending ripples up into the air.

A ground satellite has been set up in Hokitika, powerful enough to scan several hundred thousand feet into the atmosphere, with specialised weather balloons released.

Dr Brown said the westerly phenomenon itself was not the main focus, rather the energy it projects up into the "high atmosphere" as a result of the wind flow when it rises over the Southern Alps.

"The project is focusing on how that happens," he said. "New Zealand is a good location with the open ocean to the west, making it easier to understand these winds rather than elsewhere.

"A lot more energy gets pushed up into the atmosphere which isn't well modelled in weather forecasts at the moment."

The project also involves the German space agency DLER, the University of Canterbury, the National Institute of Water and Atmospheric Research (Niwa) and the MetService.

"The group working in Christchurch are using a specially modified Gulfstream jet, along with the Germans who have a Falcon 20 jet, to get high up into the atmosphere," Dr Brown said.

Dr Brown studied physics at university.

"Doing this job you have to be out in the weather and have a practical 'how to fix' attitude," he said. "Growing up on a farm here in Dannevirke where Kiwi ingenuity was needed to fix things has helped.

"People are always trying to improve climate and weather forecasting and the research we're working on is trying to improve the computer 'fudged' aspect. I've been in the Indian Ocean working on why storms clump together and next year I'll be in the central United States to learn more about thunderstorms and tornadoes."

However, Dr Brown admitted the science of the weather and climate is "complex."

"It's our job to go around helping scientists to improve forecasting, but the atmosphere has a huge effect," he said.

The main study interest for the United States here in New Zealand is how the effect of the phenomenon of westerly wind flows into the upper atmosphere relates to long-term climate modelling, whereas the New Zealand interest is more around the subtle local weather effects.

"What we've done in Hokitika is set up a lot of equipment to monitor the winds coming on to the West Coast and up into the mountains, but the bulk of the work will be done in Christchurch," Dr Brown said.

Dr Brown has found time to return to Waitahora to celebrate his mother's 90th birthday and also went back to Dannevirke High School to talk to science classes.