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 April 18, 2015 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 April 18, 2015).

Share This


More From ScienceDaily



More Earth & Climate News

Saturday, April 18, 2015

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Nervous Return to Everest a Year After Deadly Avalanche

Nervous Return to Everest a Year After Deadly Avalanche

AFP (Apr. 18, 2015) — In the Himalayan town of Lukla, excitement mingles with fear as mountaineers make their way up to Everest a year after an avalanche killed 16 guides and triggered an unprecedented shut-down of the world&apos;s highest peak. Duration: 00:37 Video provided by AFP
Powered by NewsLook.com
L.A. Water Cops Remind Residents of Water Conservation

L.A. Water Cops Remind Residents of Water Conservation

Reuters - US Online Video (Apr. 18, 2015) — "Water cops" in Los Angeles remind the public about water conservation methods amid California&apos;s prolonged drought. Julie Noce reports. Video provided by Reuters
Powered by NewsLook.com
Planet Defence Conference Tackles Asteroid Threat

Planet Defence Conference Tackles Asteroid Threat

AFP (Apr. 17, 2015) — Scientists gathered at a European Space Agency (ESA) facility outside Rome this week for the Planetary Defence Conference 2015 to discuss how to tackle the potential threat from asteroids hitting Earth. Duration: 00:54 Video provided by AFP
Powered by NewsLook.com
Gulf Scarred, Resilient 5 Years After BP Spill

Gulf Scarred, Resilient 5 Years After BP Spill

AP (Apr. 17, 2015) — Five years after the Deepwater Horizon spill in the Gulf of Mexico, splotches of oil still dot the seafloor and wads of tarry petroleum-smelling material hide in pockets in the marshes of Barataria Bay. (April 17) Video provided by AP
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