Subscribe free to our newsletters via your
. Space Travel News .




ENERGY TECH
A Push From the Mississippi Kept Deepwater Horizon Oil Slick Off Shore, Penn Research Shows
by Staff Writers
Philadelphia, PA (SPX) May 16, 2012


As the Deepwater Horizon disaster unfolded two years ago, the National Oceanic and Atmospheric Administration used information from satellite data and helicopter flights over the Gulf to produce aerial images of the shifting coat of oil. NOAA also issued daily forecasts of where the oil slick might travel, using computer models based on ocean currents.

When the Deepwater Horizon drilling rig exploded April 20, 2010, residents feared that their Gulf of Mexico shores would be inundated with oil. And while many wetland habitats and wildlife were oiled during the three-month leak, the environmental damage to coastal Louisiana was less than many expected, in part because much of the crude never made it to the coast.

Research by a trio of geoscientists, including the University of Pennsylvania's Douglas Jerolmack, now offers an explanation for why some of the oil stayed out at sea. Using publicly available datasets, their study reveals that the force of the Mississippi River emptying into the Gulf of Mexico created mounds of freshwater which pushed the oil slick off shore.

"The idea is that, if the water surface is tilting a little bit, then maybe the oil will move downhill, sort of like a ball on a plate. If you tilt the plate, the ball will roll one way and then another," Jerolmack said. "Surprisingly no one had really investigated the effect that the tilting of the water surface can have on the migration of oil."

The finding, published in the journal PLoS ONE, could help make better predictions about where oil will make landfall in future oil spills, helping to direct efforts to spare fragile coastlines and wildlife.

Jerolmack, an assistant professor in Penn's Department of Earth and Environmental Science, collaborated on the study with lead author Federico Falcini, a postdoctoral investigator in Jerolmack's lab at the time. Bruno Buongiorno Nardelli of Italy's Consiglio Nazionale delle Richerche also contributed to the work.

As the Deepwater Horizon disaster unfolded two years ago, the National Oceanic and Atmospheric Administration used information from satellite data and helicopter flights over the Gulf to produce aerial images of the shifting coat of oil. NOAA also issued daily forecasts of where the oil slick might travel, using computer models based on ocean currents.

"We noticed that there was a big disconnect between the forecasts of where the oil was going to be the next day and where the oil actually was the next day," Jerolmack said. "That maybe shouldn't be a surprise, because these computer models were not generated to forecast the movement of oil, they were generated to forecast the movement of water."

Clearly some force beyond the ocean's current was acting to direct the oil's movement. So the researchers turned their attention to the ocean's topography.

They accessed interpreted data from the Colorado Center for Astrodynamics Research that provides real-time information about sea-surface levels. These measurements, gathered from radar bounced off the surface of the ocean from the Jason2 satellite, were considered unreliable near shore, where land could confuse the signals.

The researchers performed their own analyses on the Jason2's raw data to separate out this confounding effect and glean sea-surface-level information within a few kilometers of shore. Their results confirmed the existence of several mounds and troughs in the Gulf. One mound in particular drew their attention.

"We recognized that there was a very persistent mound, a bump or a bulge, in the elevation of the sea surface in the vicinity of the Mississippi Delta," Jerolmack said.

The reason was that the oil spill coincided with the typical spring flood on the Mississippi, creating a larger-than-normal flow of water into the Delta. This powerful discharge of fresh water mounded on top of the denser salt water of the Gulf. The resulting bulge, which was approximately 10 centimeters higher than the surrounding ocean and 50-100 kilometers in diameter, was positioned so that oil from the Deepwater Horizon drilling rig ran "downhill" and away from the coast.

A mathematical model representing a two-layer fluid - comprised of oil on top and fresh water underneath - confirmed that the slope of the mound was sufficient to direct the oil's movement.

"The model was able to predict the speed at which the oil moved away from this fresh-water mound and how long it took for the oil to move away from the mound," Jerolmack said.

Despite this correlation, mound formation was just one of many competing forces driving the drift of the Gulf oil slick, Jerolmack noted.

"A mound can only form if the river discharge is relatively high and the ocean is relatively calm."

Indeed, as the Mississippi flood waters subsided and the river's discharge lessened, the bulge disappeared and the oil slick moved back toward shore. The winds of Hurricane Alex, which formed in late June 2010, also resulted in a decline in mound formation and the oil slick being pushed toward land.

Still, factoring in mound formation will help produce more accurate forecasts of oil spills around the Mississippi Delta - and perhaps predict other dispersion events as well.

"This feature is likely important not only for the oil spill, but also for the dispersal of nutrients, sediments and pollution into the Gulf," Jerolmack said.

.


Related Links
Penn's Department of Earth and Environmental Science
Powering The World in the 21st Century at Energy-Daily.com






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





ENERGY TECH
China, Japan hold sea talks on island row
Beijing (AFP) May 16, 2012
China and Japan hold high-level maritime talks on Wednesday expected to focus on a group of uninhabited islands that are at the heart of an ongoing territorial row between the two countries. China and Japan have long had strained relations, often triggered by rival sovereign claims in the East China Sea over gas fields and the disputed islands - known as the Senkaku in Japan and the Diaoyu ... read more


ENERGY TECH
SpaceX poised for high-stakes space station launch

Ariane rocket launches two Asian satellites

Key facts about SpaceX

Refurbishment on Grand Scale for Iconic VAB

ENERGY TECH
Opportunity Rolling Again After Fifth Mars Winter

Mojave Desert Tests Prepare for NASA Mars Roving

Mars Opportunity Rover Is A Go For More Travel

WSU air-quality researcher to lead field studies in support of NASA Mars mission

ENERGY TECH
Perigee "Super Moon" On May 5-6

India's second moon mission Chandrayaan-2 to wait

European Google Lunar X Prize Teams Call For Science Payloads

Russia to Send Manned Mission to Moon by 2030

ENERGY TECH
Beyond Pluto And Exploring the Kuiper Belt

Uranus auroras glimpsed from Earth

Herschel images extrasolar analogue of the Kuiper Belt

New Horizons on Approach: 22 AU Down, Just 10 to Go

ENERGY TECH
Cosmic dust rings no guarantee of planets

In search of new 'Earths' beyond our Solar System

Free-floating planets in the Milky Way outnumber stars by factors of thousands

Unseen planet revealed by its gravity

ENERGY TECH
Marshall Completes Wind Tunnel Testing For Dream Chaser Space System

NASA Continues J-2X Powerpack Testing

India conducting new round of cryogenic engine testing

Aerojet's AJ26 Flight Engine Successfully Hot-Fire Tested for Orbital's Antares Rocket

ENERGY TECH
China confirms plans to build own orbital station

Building a Heavenly Palace in outer space

Long March-2F rocket delivered to launch center

China's Lunar Docking

ENERGY TECH
NASA trains astronauts to land on asteroid

Amateur astronomers boost ESA's asteroid hunt

Dawn reveals complexities of ancient asteroidal world

NASA Dawn Mission Reveals Secrets of Large Asteroid




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement