Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Pacific trade winds stall global surface warming -- for now

10.02.2014
The strongest trade winds have driven more of the heat from global warming into the oceans; but when those winds slow, that heat will rapidly return to the atmosphere causing an abrupt rise in global average temperatures

Heat stored in the western Pacific Ocean caused by an unprecedented strengthening of the equatorial trade winds appears to be largely responsible for the hiatus in surface warming observed over the past 13 years.


This is a schematic of the trends in temperature and ocean-atmosphere circulation in the Pacific over the past two decades. Color shading shows observed temperature trends (C per decade) during 1992-2011 at the sea surface (Northern Hemisphere only), zonally averaged in the latitude-depth sense (as per Supplementary Fig. 6) and along the equatorial Pacific in the longitude-depth plane (averaged between 5 N S). Peak warming in the western Pacific thermocline is 2.0C per decade in the reanalysis data and 2.2C per decade in the model. The mean and anomalous circulation in the Pacific Ocean is shown by bold and thin arrows, respectively, indicating an overall acceleration of the Pacific Ocean shallow overturning cells, the equatorial surface currents and the Equatorial Undercurrent (EUC). The accelerated atmospheric circulation in the Pacific is indicated by the dashed arrows; including theWalker cell (black dashed) and the Hadley cell (red dashed; Northern Hemisphere only). Anomalously high SLP in the North Pacific is indicated by the symbol "H." An equivalent accelerated Hadley cell in the Southern Hemisphere is omitted for clarity.

Credit: From Nature Climate Change

New research published today in the journal Nature Climate Change indicates that the dramatic acceleration in winds has invigorated the circulation of the Pacific Ocean, causing more heat to be taken out of the atmosphere and transferred into the subsurface ocean, while bringing cooler waters to the surface.

"Scientists have long suspected that extra ocean heat uptake has slowed the rise of global average temperatures, but the mechanism behind the hiatus remained unclear" said Professor Matthew England, lead author of the study and a Chief Investigator at the ARC Centre of Excellence for Climate System Science.

"But the heat uptake is by no means permanent: when the trade wind strength returns to normal - as it inevitably will - our research suggests heat will quickly accumulate in the atmosphere. So global temperatures look set to rise rapidly out of the hiatus, returning to the levels projected within as little as a decade."

The strengthening of the Pacific trade winds began during the 1990s and continues today. Previously, no climate models have incorporated a trade wind strengthening of the magnitude observed, and these models failed to capture the hiatus in warming. Once the trade winds were added by the researchers, the global average temperatures very closely resembled the observations during the hiatus.

"The winds lead to extra ocean heat uptake, which stalled warming of the atmosphere. Accounting for this wind intensification in model projections produces a hiatus in global warming that is in striking agreement with observations," Prof England said.

"Unfortunately, however, when the hiatus ends, global warming looks set to be rapid."

The impact of the trade winds on global average temperatures is caused by the winds forcing heat to accumulate below surface of the Western Pacific Ocean.

"This pumping of heat into the ocean is not very deep, however, and once the winds abate, heat is returned rapidly to the atmosphere" England explains.

"Climate scientists have long understood that global average temperatures don't rise in a continual upward trajectory, instead warming in a series of abrupt steps in between periods with more-or-less steady temperatures. Our work helps explain how this occurs," said Prof England.

"We should be very clear: the current hiatus offers no comfort - we are just seeing another pause in warming before the next inevitable rise in global temperatures."

Alvin Stone | EurekAlert!
Further information:
http://www.unsw.edu.au

More articles from Earth Sciences:

nachricht California rising
04.09.2015 | University of California - Santa Barbara

nachricht NASA's Aqua Satellite sees Typhoon Kilo headed west
04.09.2015 | NASA/Goddard Space Flight Center

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Hubble survey unlocks clues to star birth in neighboring galaxy

In a survey of NASA's Hubble Space Telescope images of 2,753 young, blue star clusters in the neighboring Andromeda galaxy (M31), astronomers have found that M31 and our own galaxy have a similar percentage of newborn stars based on mass.

By nailing down what percentage of stars have a particular mass within a cluster, or the Initial Mass Function (IMF), scientists can better interpret the light...

Im Focus: Fraunhofer ISE Develops Highly Compact Inverter for Uninterruptible Power Supplies

Silicon Carbide Components Enable Efficiency of 98.7 percent

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE have developed a highly compact and efficient inverter for use in uninterruptible power...

Im Focus: How wind sculpted Earth's largest dust deposit

China's Loess Plateau was formed by wind alternately depositing dust or removing dust over the last 2.6 million years, according to a new report from University of Arizona geoscientists. The study is the first to explain how the steep-fronted plateau formed.

China's Loess Plateau was formed by wind alternately depositing dust or removing dust over the last 2.6 million years, according to a new report from...

Im Focus: An engineered surface unsticks sticky water droplets

The leaves of the lotus flower, and other natural surfaces that repel water and dirt, have been the model for many types of engineered liquid-repelling surfaces. As slippery as these surfaces are, however, tiny water droplets still stick to them. Now, Penn State researchers have developed nano/micro-textured, highly slippery surfaces able to outperform these naturally inspired coatings, particularly when the water is a vapor or tiny droplets.

Enhancing the mobility of liquid droplets on rough surfaces could improve condensation heat transfer for power-plant heat exchangers, create more efficient...

Im Focus: Increasingly severe disturbances weaken world's temperate forests

Longer, more severe, and hotter droughts and a myriad of other threats, including diseases and more extensive and severe wildfires, are threatening to transform some of the world's temperate forests, a new study published in Science has found. Without informed management, some forests could convert to shrublands or grasslands within the coming decades.

"While we have been trying to manage for resilience of 20th century conditions, we realize now that we must prepare for transformations and attempt to ease...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Together - Work - Experience

03.09.2015 | Event News

Networking conference in Heidelberg for outstanding mathematicians and computer scientists

20.08.2015 | Event News

Scientists meet in Münster for the world’s largest Chitin und Chitosan Conference

20.08.2015 | Event News

 
Latest News

Ion implanted, co-annealed, screen-printed 21% efficient n-PERT solar cells with a bifaciality >97%

04.09.2015 | Power and Electrical Engineering

Casting of SiSiC: new perspectives for chemical and plant engineering

04.09.2015 | Machine Engineering

Extremely thin ceramic components made possible by extrusion

04.09.2015 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>