NIWA to Study Deep Ocean’s Effects on Climate

Two plastic-encased glass balls, measuring 35 cm in diameter, will be deployed from NIWA’s flagship research vessel Tangaroa east of the Kermadec Trench in a scientific first aimed at adding to our understanding of global climate change.

Called Deep Argo floats, they contain sensors to measure temperature and salinity between the surface and about 6000m deep, along with devices to transmit the data to satellites.

This is the first time these measuring instruments will be tested at such depths and represent the next stage in the international Argo programme.

Current Argo floats take measurements in the top 2000m of our oceans and since the programme’s inception in 1999, NIWA has played a key role in deploying floats to maintain the more than 3000 that are now in place around the globe.

Argo floats work by first sinking down to about 1km below sea level. Every nine days they sink to 2km before coming back up to the ocean surface. As the float rises, it measures temperature and salinity through the water column. On the surface the data and position of the float are transmitted via satellite before the float repeats the process.

The data collected, which are freely available, are helping improve our understanding of the oceans’ role in climate as well as our weather and climate prediction systems.

However, NIWA oceanographer Phil Sutton says the deep ocean could play a crucial role in shaping the earth’s climate and not enough is known about what happens below 2000m.

Seattle company Sea-bird Electronics has now developed sensors for Deep Argo floats being developed at Scripps Institution of Oceanography for this purpose and the developers will join scientists on the voyage to test their prototypes.

“This is really leading-edge emerging technology that will, for the first time, allow us to fill in the gap in data between 2000m and the sea floor,” Dr Sutton says.

Press Release, June 17, 2014