Free Newsletters - Space - Defense - Environment - Energy - Solar - Nuclear
..
. Earth Science News .




WATER WORLD
Rapid upper ocean warming linked to declining aerosols
by Staff Writers
Canberra, Australia (SPX) Jul 24, 2013


Deploying a deep ocean mooring system in the Indian Ocean.

They partly attribute the observed warming, and preceding cooling trends to ocean circulation changes induced by global greenhouse gas emissions and aerosols predominantly generated in the Northern Hemisphere from human activity.

The research, by scientists from CSIRO and the University of NSW, was published in Scientific Reports.

Mr Tim Cowan, lead author of the study, says his group was initially interested in the three decade long cooling below the surface of the Southern Hemisphere subtropical oceans from the 1960s and 1990s. "But what really caught our eye was a rapid warming of these subtropical oceans from the mid-1990s, most noticeably in the Indian Ocean between 300 m to 1000 m depth," said Mr Cowan.

This had the research team asking whether this rapid warming was partly a response to greenhouse gases overcoming the cooling effect of aerosols that peaked globally in the 1980s due to the introduction of clean air legislation across United States and Europe.

To test this, the researchers examined more than 40 state-of-the-art climate simulations that included historical changes to greenhouse gases and aerosols over the twentieth century.

"What we found was that the models do a good job at simulating the late twentieth century cooling and rapid warming in the subtropical southern Atlantic and Pacific Oceans, however they show an around 30-year delay in the warming in the Indian Ocean" said Mr Cowan.

"This delay in the modelled Indian Ocean warming is likely due to the presence of atmospheric aerosols, generated through transport emissions, biomass burning, and industrial smog, together with natural emissions of sea salt and dust - these were also the main cause of the late twentieth century subtropical Indian Ocean below-surface cooling" said Mr Cowan.

The researchers found that models with a delayed peak in Northern Hemisphere aerosol levels after the 1980s had a tendency to simulate a delayed rapid Indian Ocean warming until well after 2020, and that the rate of warming related to how quickly the aerosol levels declined after their peak.

"We know that aerosols in the atmosphere generally cool the Northern Hemisphere by scattering incoming sunlight. This, in turn, increases the movement of heat from the Southern Hemisphere oceans to the Northern Hemisphere oceans via a global oceanic conveyor belt, travelling south from the subtropical Indian Ocean, passing the southern tip of Africa into the south Atlantic and then north along the Gulf Stream" said co-author Dr Wenju Cai.

"Together with a greenhouse gas-induced southward shift the Indian subtropical ocean gyres towards the Antarctic, these processes delay the Indian Ocean warming in the models," Dr Cai said.

"What makes this work fascinating is the fact that human-emitted aerosols have such a large impact on remote ocean temperatures" says Mr Cowan. "For many years aerosols have masked the direct surface warming induced by greenhouse gases in many Northern Hemisphere regions, however in the Southern subtropical Indian Ocean both aerosols and greenhouse gases have historically conspired to produce a net oceanic cooling, and now the reverse of some of these processes is occurring."

Mr Cowan said that despite the observed rapid ocean warming, quantifying exactly how much is due to declining aerosols or increasing greenhouse gases remains difficult, but as human-generated air pollution is all-together phased out, this will undoubtedly reveal the full impact of greenhouse gases.

The research has been supported by the CSIRO Wealth from Oceans National Research Flagship, The Australian Climate Change Science Program and the Australian Research Council Centre of Excellence in Climate System Science.

.


Related Links
CSIRO
Water News - Science, Technology and Politics






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





WATER WORLD
Scotland backs Hebrides conservation area despite fishing objections
Barra, Scotland (UPI) Jul 22, 2013
Scotland has designated a pristine marine area in Hebrides Islands as a European Union "special area of conservation" despite strong opposition from fishermen. Scottish Environment Minister Paul Wheelhouse announced Friday the Sound of Barra will be submitted to Brussels for inclusion in the EU-wide network of SACs, capping 13 years of controversy spurred by fears its elimination as a s ... read more


WATER WORLD
More steam in Fukushima reactor building: TEPCO

Fukushima steam still baffling: TEPCO

The best defense against catastrophic storms: Mother Nature, say Stanford researchers

NASA, International Space Agencies Note Benefits of Space Station during Disasters on Earth

WATER WORLD
Magnets make droplets dance

Delayed Shield game gadget to hit market on July 31

World's cheapest computer gets millions tinkering

Thyroid cancer risk for 2,000 Fukushima workers: TEPCO

WATER WORLD
Scotland backs Hebrides conservation area despite fishing objections

Rapid upper ocean warming linked to declining aerosols

First global atlas of marine plankton reveals remarkable underwater world

From obscurity to dominance: Tracking the rapid evolutionary rise of ray-finned fish

WATER WORLD
Ancient Antarctic ice got muddy

Russia blocks bid for Antarctic sanctuary: NGOs

Continuous satellite monitoring of ice sheets needed to better predict sea-level rise

Researchers Shed New Light on Supraglacial Lake Drainage

WATER WORLD
Scientists sound new warning for arsenic in rice

Malawi faces food shortage

Maize trade disruption could have global ramifications

Why crop rotation works

WATER WORLD
Rescuers battle to find China quake survivors

Quake shatters migrants' dream of better life for son

China quake survivors bury their dead

At least 89 dead in China earthquakes: state media

WATER WORLD
Post-mortem on French operation in Mali

Nigeria to withdraw some troops from Mali

Climate change to hit Volta Basin for energy, farming

A South Sudan moka? What else?

WATER WORLD
Archaeologist says he's uncovered King David's palace

Brain signal said to create inner 'voice' we hear even if we're silent

Genetic evolution seen in peoples living at high altitudes

China island centenarians claim secret of long life




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