Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

CCNY professor foresees rising Antarctic snowmelt

07.12.2009
Marco Tedesco Says Record Low Resulted From Simultaneous Positive Phases for Two Climate Drivers

The 30-year record low in Antarctic snowmelt that occurred during the 2008-09 austral summer was likely due to concurrent strong positive phases for two main climate drivers, ENSO (El Niño - Southern Oscillation) and SAM (Southern Hemisphere Annular Mode), according to Dr. Marco Tedesco, Assistant Professor of Earth & Atmospheric Sciences at The City College of New York.

Professor Tedesco, who is also on the doctoral faculty at the CUNY Graduate Center, added that Antarctic snowmelt levels should revert to higher norms as one of the drivers, the SAM, subsides as the damage to the ozone layer is repaired. His conclusions, which are based on space-borne microwave observations between 1979 and 2009, were reported in “Geophysical Research Letters” earlier this fall.

“The study’s goal was not only to report on melting but also on the relationship between melting and the climate drivers, El Niño and the SAM,” he explained. Low melt years during the 1979-2009 satellite record are related to the strength of the westerly winds that encircle Antarctica, known as the Southern Hemisphere Annular Mode (SAM).

“When the SAM is in a positive phase – meaning that the belt of winds is stronger than average – it has a cooling effect on Antarctic surface temperatures,” he explained. “The SAM was especially strong in austral spring and summer 2008-2009, and subsequently the 2008-2009 snowmelt was lower than normal.”

During the past 30-40 years, the SAM has gradually strengthened during austral summer, due mainly to human-caused stratospheric ozone depletion, he continued. However, as the hole is repaired as a result of compliance with the Montreal protocol, the winds will weaken and Antarctica will be subject to more warming air.

The increasing summer SAM trends are projected to subside, he added. “It is likely that summer temperature increases over Antarctica will become stronger and more widespread because the warming effect from greenhouse gas increases will no longer be kept by the weakened circumpolar winds. The bottom line is as the ozone layer recovers we’ll likely have more melting on Antarctica.”

According to Professor Tedesco, variability in El Niño and the SAM account for up to 50 percent of the variations in Antarctic snowmelt. However, the melting trends over the whole continent derived from satellite data are not statistically significant, he noted.

“If you add one year of data, the trend could shift from positive to negative or vice versa. Thirty years is not enough to tell the overall trend for Antarctica.” However, he noted that studies based on land observations with data going back to the 1950s support a warming trend, especially on the Antarctic Peninsula.

Ellis Simon | EurekAlert!
Further information:
http://www.ccny.cuny.edu

Further reports about: Antarctic Predators Antarctica CCNY El Niño Hemisphere ozone layer

More articles from Earth Sciences:

nachricht New research calculates capacity of North American forests to sequester carbon
16.07.2018 | University of California - Santa Cruz

nachricht Scientists discover Earth's youngest banded iron formation in western China
12.07.2018 | University of Alberta

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

NYSCF researchers develop novel bioengineering technique for personalized bone grafts

18.07.2018 | Life Sciences

Machine-learning predicted a superhard and high-energy-density tungsten nitride

18.07.2018 | Materials Sciences

Why might reading make myopic?

18.07.2018 | Health and Medicine

VideoLinks
Science & Research
Overview of more VideoLinks >>>