Featured Research

from universities, journals, and other organizations

Fiber Optics Used To Measure Water And Air

Date:
June 16, 2008
Source:
Oregon State University
Summary:
Scientists are using fiber optics to study the temperature of water, the flow of air, and the dynamics of snow melt. This technology -- called distributed temperature sensing (DTS) -- uses the same sort of fiber optic communication cables that make your telephone work, to measure temperatures at one-meter intervals over distances exceeding 10 kilometers.

John Selker is using fiber optics to study the temperature of water, the flow of air, and the dynamics of snow melt.
Credit: Image courtesy of Oregon State University

Scientists at Oregon State University are using fiber optics to study the temperature of water, the flow of air, and the dynamics of snow melt.

Related Articles


This technology – called distributed temperature sensing (DTS) – uses the same sort of fiber optic communication cables that make your telephone work, to measure temperatures at one-meter intervals over distances exceeding 10 kilometers.

An intense laser pulse is sent down the fiber and the fiber's temperature is computed from the light that bounces back – the warmer the fiber, the more blue-shifted light returns.

"We are able to monitor changes in temperature with greater than 10,000 times the resolution possible a few years ago," said John Selker, a professor of biological and ecological engineering at OSU who has pioneered the new use of this technology.

Selker and his team are using fiber optics in ways that were never imagined by the original developers, which presents challenges in equipment selection, installation, and data analysis. To explore new applications and ensure their availability to researchers, Selker is testing the technology in a series of intensive, hands-on workshops.

Results from tests conducted on the H.J. Andrews Experimental Forest in the western Cascade Mountains of Oregon are reported in the latest issue of the journal Eos, Transactions, American Geophysical Union.

The tests involved three field installations of fiber optic cables. Two installations collected data from streams, recording the dynamic interplay between groundwater and surface water.

"There's a big difference between the stream we see and the stream we don't see," said Selker. Even as the sun and air warm a stream up, the permeable bed underlying it cools it down, soaking up heat as water filters through during the day, and re-cooling at night.

To quantify this thermal exchange, workshop participants used a sack of ice placed in the stream, then followed the pulse of cold water using DTS. When the streambed was deep, the cold pulse dissipated almost immediately. But in sections where the streambed was lined with bedrock, where water could not enter and reemerge, the cold signal traveled for hundreds of meters.

Selker then revealed the invisible part of the stream by translating meter-by-meter temperature observations into a detailed map of the hidden, sub-surface portion – which often holds more water than flows on the surface.

The third installation used a crisscrossed series of fiber optic cables spanning a mountain valley to record the dynamic current of cold air carrying carbon dioxide exhaled by the forest.

Just as the cables in the stream mapped slight differences in water temperature across a gradient, the cables spanning the valley outlined an invisible river that carries cold forest air down the mountainside as the sky darkens.

Selker hopes to show that by running a current along the electrically resistive metal casing of a fiber optic cable, researchers can measure wind speed and air temperature at thousands of points simultaneously from the forest canopy to the valley floor.

His lab has already used this approach to help farmers understand their irrigation systems, hydrologists quantify the water moving underground and geologists document the temperatures of snowpacks.

New environmental applications of DTS emerge almost every day. "It's been quite a ride since a couple of years ago when we first put this technology into a stream," said Selker.


Story Source:

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


Cite This Page:

Oregon State University. "Fiber Optics Used To Measure Water And Air." ScienceDaily. ScienceDaily, 16 June 2008. <www.sciencedaily.com/releases/2008/06/080616161826.htm>.
Oregon State University. (2008, June 16). Fiber Optics Used To Measure Water And Air. ScienceDaily. Retrieved November 25, 2014 from www.sciencedaily.com/releases/2008/06/080616161826.htm
Oregon State University. "Fiber Optics Used To Measure Water And Air." ScienceDaily. www.sciencedaily.com/releases/2008/06/080616161826.htm (accessed November 25, 2014).

Share This


More From ScienceDaily



More Matter & Energy News

Tuesday, November 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Who Will Failed Nuclear Talks Hurt Most?

Who Will Failed Nuclear Talks Hurt Most?

Reuters - Business Video Online (Nov. 25, 2014) With no immediate prospect of sanctions relief for Iran, and no solid progress in negotiations with the West over the country's nuclear programme, Ciara Lee asks why talks have still not produced results and what a resolution would mean for both parties. Video provided by Reuters
Powered by NewsLook.com
Flying Enthusiast Converts Real-Life Aircraft Cockpit Into Simulator

Flying Enthusiast Converts Real-Life Aircraft Cockpit Into Simulator

Reuters - Innovations Video Online (Nov. 25, 2014) A virtual flying enthusiast converts parts of a written-off Airbus aircraft into a working flight simulator in his northern Slovenian home. Jim Drury 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
Microsoft Adds Robot Guards, Ushers In Sci-Fi Apocalypse

Microsoft Adds Robot Guards, Ushers In Sci-Fi Apocalypse

Newsy (Nov. 23, 2014) Microsoft has robotic security guards working at its Silicon Valley Campus. Video provided by Newsy
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


Space & Time

Matter & Energy

Computers & Math

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