(Press-News.org) Research from the University of Sheffield has shown that unusual changes in atmospheric jet stream circulation caused the exceptional surface melt of the Greenland Ice Sheet (GrIS) in summer 2012.
An international team led by Professor Edward Hanna from the University of Sheffield's Department of Geography used a computer model simulation (called SnowModel) and satellite data to confirm a record surface melting of the GrIS for at least the last 50 years - when on 11 July 2012, more than 90 percent of the ice-sheet surface melted. This far exceeded the previous surface melt extent record of 52 percent in 2010.
The team also analysed weather station data from on top of and around the GrIS, largely collected by the Danish Meteorological Institute but also by US programmes, which showed that several new high Greenland temperature records were set in summer 2012.
The research, published today in the International Journal of Climatology, clearly demonstrates that the record surface melting of the GrIS was mainly caused by highly unusual atmospheric circulation and jet stream changes, which were also responsible for last summer's unusually wet weather in England.
The analysis shows that ocean temperatures and Arctic sea-ice cover were relatively unimportant factors in causing the extra Greenland melt.
Professor Hanna said: "The GrIS is a highly sensitive indicator of regional and global climate change, and has been undergoing rapid warming and mass loss during the last 5-20 years. Much attention has been given to the NASA announcement of record surface melting of the GrIS in mid-July 2012. This event was unprecedented in the satellite record of observations dating back to the 1970s and probably unlikely to have occurred previously for well over a century.
"Our research found that a 'heat dome' of warm southerly winds over the ice sheet led to widespread surface melting. These jet stream changes over Greenland do not seem to be well captured in the latest Intergovernmental Panel on Climate Change (IPCC) computer model predictions of climate change, and this may indicate a deficiency in these models. According to our current understanding, the unusual atmospheric circulation and consequent warm conditions of summer 2012 do not appear to be climatically representative of future 'average' summers predicted later this century.
"Taken together, our present results strongly suggest that the main forcing of the extreme GrIS surface melt in July 2012 was atmospheric, linked with changes in the summer North Atlantic Oscillation (NAO), Greenland Blocking Index (GBI, a high pressure system centred over Greenland) and polar jet stream which favoured southerly warm air advection along the western coast.
"The next five-10 years will reveal whether or not 2012 was a rare event resulting from the natural variability of the NAO or part of an emerging pattern of new extreme high melt years. Because such atmospheric, and resulting GrIS surface climate, changes are not well projected by the current generation of global climate models, it is currently very hard to predict future changes in Greenland climate. Yet it is crucial to understand such changes much better if we are to have any hope of reliably predicting future changes in GrIS mass balance, which is likely to be a dominant contributor to global sea-level change over the next 100-1000 years."
INFORMATION:
Jet stream changes cause climatically exceptional Greenland Ice Sheet melt
2013-06-17
ELSE PRESS RELEASES FROM THIS DATE:
Drivers happy to take long way round to avoid traffic stress
2013-06-17
German motorists are willing to accept longer journey times and even detours if it means helping to ease the general traffic situation. This emerged from a recent user study carried out by the Fraunhofer Institute for Open Communication Systems FOKUS in cooperation with the Technische Universität Berlin. Of 120 motorists who agreed to provide information about their driving habits and attitudes towards road traffic, two-thirds said they would rather have a stress-free trip even if it meant adding over three minutes to their journey, and 75 percent said they would even be ...
Polymer-coated catalyst protects 'artificial leaf'
2013-06-17
This news release is available in German. Researchers at the HZB Institute for Solar Fuels have modified so called superstrate solar cells with their highly efficient architecture in order to obtain hydrogen from water with the help of suitable catalysts. This type of cell works something like an "artificial leaf." But the solar cell rapidly corrodes when placed in the aqueous electrolyte solution.
Now, Ph.D. student Diana Stellmach has found a way to prevent corrosion by embedding the catalysts in an electrically conducting polymer and then mounting them onto the ...
CNIC researchers find a possible treatment for one of the main symptoms of premature aging disease
2013-06-17
HGPS is a rare genetic disease that affects one in every 4-8 million births. The disease is caused by a spontaneous mutation in one of the two copies (alleles) of the gene LMNA, which codes for lamin A, a protein important for the integrity and function of the envelope surrounding the cell nucleus. The mutation causes incorrect processing of the messenger RNA for lamin proteins, resulting in the synthesis of an anomalous protein, called progerin.
The new study, published in the leading cardiovascular research journal Circulation, identifies a possible treatment to block ...
Efficient and inexpensive: Researchers develop catalyst material for fuel cells
2013-06-17
This news release is available in German. Efficient, robust and economic catalyst materials hold the key to achieving a breakthrough in fuel cell technology. Scientists from Jülich and Berlin have developed a material for converting hydrogen and oxygen to water using a tenth of the typical amount of platinum that was previously required. With the aid of state-of-the-art electron microscopy, the researchers discovered that the function of the nanometre-scale catalyst particles is decisively determined by their geometric shape and atomic structure. This discovery opens ...
Perching on the cliffs of New Zealand, endemic Lepidium flora faces extinction threats
2013-06-17
The plant genus Lepidiums is a small group of representatives of the economically important cabbage family Brassicaceae. Most commonly known as peppercress or peppergrass Lepidiums includes around 180 species worldwide. In a new extensive study, published in the open access journal PhytoKeys, scientists explore the diversity within the New Zealand Lepidiums oleraceum and allied species.
Lepidiums oleraceum, is known in New Zealand, as "Cook's Scurvy Grass" because Captain James Cook, and other early explorers of that island nation, ate the plant as a scurvy preventive. ...
Mice in a 'big brother' setup develop social structures
2013-06-17
How does a social animal – mouse or human – gain dominance over his or her fellow creatures? A unique experiment conducted by Dr. Tali Kimchi and her team in the Weizmann Institute's Neurobiology Department provides some unusual insight into the social behavior that enables a social hierarchy, complete with a head honcho, to form.
Kimchi and her research team, Aharon Weissbrod, Genady Wasserman and Alex Shapiro, together with Dr. Ofer Feinerman of the Institute's Physics of Complex Systems Department, developed a system that enabled them to observe a large group of animals ...
Chemical in antibacterial soap fed to nursing rats harms offspring
2013-06-17
SAN FRANCISCO—- A mother's exposure to triclocarban, a common antibacterial chemical, while nursing her babies shortens the life of her female offspring, a new study in rats finds. The results were presented Monday at The Endocrine Society's 95th Annual Meeting in San Francisco.
Commonly used in antibacterial soap and other personal care products, triclocarban has the potential for a large portion of the public to be exposed to it, said the study's lead author, Rebekah Kennedy, a graduate student in the Department of Public Health at the University of Tennessee, Knoxville.
"Our ...
Prenatal exposure to BPA affects fat tissues in sheep
2013-06-17
SAN FRANCISCO-— New research suggests that fetal exposure to the common environmental chemical bisphenol A, or BPA, causes increased inflammation in fat tissues after birth, which can lead to obesity and metabolic syndrome. Results of the animal study were presented Monday at The Endocrine Society's 95th Annual Meeting in San Francisco.
Found in plastic water bottles, older baby bottles and many other consumer products, BPA is a known hormone disrupter with estrogen-like properties. Prior research has linked BPA in both animals and humans to obesity and the metabolic ...
Infections increase risk of mood disorders
2013-06-17
New research shows that every third person who is diagnosed for the first time with a mood disorder has been admitted to hospital with an infection prior to the diagnosis. The study is the largest of its kind to date to show a clear correlation between infection levels and the risk of developing mood disorders.
Anyone can suffer from an infection, for example in their stomach, urinary tract or skin. It would now appear that their distress does not necessarily end once the infection has been treated. A new PhD project shows that many people subsequently suffer from a mood ...
Researchers find genetic diversity key to survival of honey bee colonies
2013-06-17
When it comes to honey bees, more mates is better. A new study from North Carolina State University, the University of Maryland and the U.S. Department of Agriculture (USDA) shows that genetic diversity is key to survival in honey bee colonies – meaning a colony is less likely to survive if its queen has had a limited number of mates.
"We wanted to determine whether a colony's genetic diversity has an impact on its survival, and what that impact may be," says Dr. David Tarpy, an associate professor of entomology at North Carolina State University and lead author of a ...