NZ scientists embark on major ocean-climate study to Chile

A New Zealand research vessel will set sail from Wellington Harbour this Sunday bound for Chile as part of a major international project to understand and predict the phenomena influencing the world’s climate.

During the voyage, John Hunt from NIWA will deploy 61 high-tech drifting floats into the ocean from the NIWA research vessel Kaharoa. The floats, worth $20,000 each, will provide real-time measurements of the temperature and salinity of the upper ocean that will help forecast long-term climate change, and events like El Niño and tropical cyclones. Each float will collect about 140 temperature and salinity profiles, and provide valuable information on the ocean currents before its batteries run out in about 5 years.

‘The float sinks to a depth of between 1600 and 2000 meters where it remains for nine or ten days, being carried by ocean currents,’ said NIWA oceanographer Philip Sutton. ‘It then rises to the surface, measuring the temperature and the salinity through the water column as it ascends. Once on the surface, the float transmits this information and its location via a satellite.’

Dr Sutton said 30 floats would be deployed between Wellington and Chile, with the other 31 floats deployed on the return journey from Chile to Wellington. ‘We don’t have much information on the temperature and salinity of the South Pacific, so these floats will play a very important role in helping to fill this gap,’ said Dr Sutton.

The voyage – the first of three planned by NIWA this year – is a joint collaboration between NIWA, University of Washington (Seattle), and Scripps Institution of Oceanography (San Diego). These deployments contribute towards a global programme called Argo, which aims to deploy and maintain 3,000 drifting floats in the world’s oceans by 2006. There are currently 1029 active floats deployed by 17 countries in operation throughout the world’s oceans.

‘Information from all the floats is shared internationally, and will be invaluable for monitoring the state of the ocean, predicting weather and cyclones, and studying global climate,’ said Dr Sutton.

To view the current global float status, see www.argo.ucsd.edu/index.html