Featured Research

from universities, journals, and other organizations

Science Adopts A New Definition Of Seawater

Date:
July 30, 2009
Source:
CSIRO Australia
Summary:
The world's peak ocean science body has adopted a new definition of seawater developed by scientists to make climate projections more accurate.

This instrument deployed from a research vessel measures temperature and salinity in the ocean. Variations in salinity and heat influence ocean currents and measuring those variations is central to quantifying the ocean's role in climate change.
Credit: CSIRO

The world's peak ocean science body has adopted a new definition of seawater developed by Australian, German and US scientists to make climate projections more accurate.

Related Articles


In Paris in June of 2009 the General Assembly of UNESCO's Intergovernmental Oceanographic Commission (IOC) accepted the case for the introduction of a new international thermodynamic description of seawater, cast in terms of a new salinity variable called Absolute Salinity.

Hobart-based CSIRO Wealth from Oceans Flagship scientist, Dr Trevor McDougall, made the case during his presentation of the Bruun Memorial Lecture to the Paris meeting.

"Scientists will now have an accurate measure of the heat content of seawater for inclusion in ocean models and climate projections," Dr McDougall says.

"Variations in salinity and heat influence ocean currents and measuring those variations are central to quantifying the ocean's role in climate change. The new values for salinity, density and heat content should be in widespread use within 18 months."

Marine scientists have been searching for the 'magic formula' for measuring salinity – which varies from ocean to ocean and between tropical, temperate and polar regions – for more than 150 years.

"These variations in salinity and temperature are responsible for driving deep ocean currents and the major vertical overturning circulations of the world's oceans, which transfer ocean heat towards the Arctic and Antarctic regions," Dr McDougall says.

Unchanged since the last assessment 30 years ago, the case to review ocean thermodynamic measurements began in 2005 when the Scientific Committee on Oceanic Research (SCOR) established a working group, chaired by Dr McDougall. Supporting him were Dr Rainer Feistel from the Leibniz-Institut für Ostseeforschung in Warnemünde (Germany), Dr Frank Millero, from the Rosenstiel School of Marine and Atmospheric Science at the University of Miami in Florida, Dr Dan Wright of the Bedford Institute of Oceanography, Canada and Dr David Jackett of CSIRO.

Salinity, comprising the salts washed from rocks, is measured using the conductivity of seawater – a technique which assumes that the composition of salt in seawater is the same in all the world's oceans.

"The new approach, involving Absolute Salinity, takes into account the changes in the composition of seasalt between different ocean basins which, while small, are a factor of about 10 larger than the accuracy with which scientists can measure salinity at sea," Dr McDougall says.

Until the new description of seawater is widely adopted, ocean models will continue to assume that the heat content of seawater is proportional to a particular temperature variable called "potential temperature".

"The new description allows scientists to calculate the errors involved by using this approximation while also presenting a much more accurate measure of the heat content of seawater, namely Conservative Temperature," Dr McDougall says.

"The difference is mostly less than 1ºC at the sea surface, but it is important to correct for these biases in ocean models."


Story Source:

The above story is based on materials provided by CSIRO Australia. Note: Materials may be edited for content and length.


Cite This Page:

CSIRO Australia. "Science Adopts A New Definition Of Seawater." ScienceDaily. ScienceDaily, 30 July 2009. <www.sciencedaily.com/releases/2009/07/090720102012.htm>.
CSIRO Australia. (2009, July 30). Science Adopts A New Definition Of Seawater. ScienceDaily. Retrieved November 26, 2014 from www.sciencedaily.com/releases/2009/07/090720102012.htm
CSIRO Australia. "Science Adopts A New Definition Of Seawater." ScienceDaily. www.sciencedaily.com/releases/2009/07/090720102012.htm (accessed November 26, 2014).

Share This


More From ScienceDaily



More Earth & Climate News

Wednesday, November 26, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Antarctic Sea Ice Mystery Thickens... Literally

Antarctic Sea Ice Mystery Thickens... Literally

Newsy (Nov. 25, 2014) — Antarctic sea ice isn't only expanding, it's thicker than previously thought, and scientists aren't sure exactly why. Video provided by Newsy
Powered by NewsLook.com
3D Map of Antarctic Sea Ice to Shed Light on Climate Change

3D Map of Antarctic Sea Ice to Shed Light on Climate Change

Reuters - Innovations Video Online (Nov. 24, 2014) — A multinational group of scientists have released the first ever detailed, high-resolution 3-D maps of Antarctic sea ice. Using an underwater robot equipped with sonar, the researchers mapped the underside of a massive area of sea ice to gauge the impact of climate change. Ben Gruber reports. Video provided by Reuters
Powered by NewsLook.com
Car Park Solution for Flexible Green Energy

Car Park Solution for Flexible Green Energy

Reuters - Innovations Video Online (Nov. 24, 2014) — A British solar power start-up says that by covering millions of existing car park spaces around the UK with flexible solar panels, the country's power problems could be solved. Suzannah Butcher reports. Video provided by Reuters
Powered by NewsLook.com
Yellow-Spotted Turtles Rescued from Trafficking

Yellow-Spotted Turtles Rescued from Trafficking

Reuters - Light News Video Online (Nov. 24, 2014) — Hundreds of Amazon River turtles released into the wild in Peru. Sharon Reich reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins