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Landsat 8 helps unveil the coldest place on Earth

Scientists recently recorded the lowest temperatures on Earth at a desolate and remote ice plateau in East Antarctica, trumping a record set in 1983 and uncovering a new puzzle about the ice-covered continent.

Ted Scambos, lead scientist at the National Snow and Ice Data Center (NSIDC), and his team found temperatures from -92 to -94 degrees Celsius (-134 to -137 degrees Fahrenheit) in a 1,000-kilometer long swath on the highest section of the East Antarctic ice divide.

The measurements were made between 2003 and 2013 by the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor on board NASA's Aqua satellite and during the 2013 Southern Hemisphere winter by Landsat 8, a new satellite launched early this year by NASA and the U.S. Geological Survey.

"I've never been in conditions that cold and I hope I never am," Scambos said. "I am told that every breath is painful and you have to be extremely careful not to freeze part of your throat or lungs when inhaling."

The record temperatures are several degrees colder than the previous record of -89.2 degrees Celsius (-128.6 degrees Fahrenheit) measured on July 21, 1983 at the Vostok Research Station in East Antarctica. They are far colder than the lowest recorded temperature in the United States, measured at -62 degrees Celsius (-79.6 degrees Fahrenheit) in Alaska, in northern Asia at -68 degrees Celsius (-90.4 degrees Fahrenheit), or even at the summit of the Greenland Ice Sheet at -75 degrees Celsius (-103 degrees Fahrenheit).

Scambos said the record temperatures were found in several 5 by 10 kilometer (3 by 6 mile) pockets where the topography forms small hollows of a few meters deep (2 to 4 meters, or 6 to 13 feet). These hollows are present just off the ice ridge that runs between Dome Argus and Dome Fuji -- the ice dome summits of the East Antarctic Ice Sheet. Antarctic bases sit on each of the sites and are generally not occupied during Antarctic winters.

Under clear winter skies in these areas, cold air forms near the snow surface. Because the cold air is denser than the air above it, it begins to move downhill. The air collects in the nearby hollows and chills still further, if conditions are favorable.

"The record-breaking conditions seem to happen when a wind pattern or an atmospheric pressure gradient tries to move the air back uphill, pushing against the air that was sliding down," Scambos said. "This allows the air in the low hollows to remain there longer and cool even further under the clear, extremely dry sky conditions," Scambos said. "When the cold air lingers in these pockets it reaches ultra-low temperatures."

"Any gardener knows that clear skies and dry air in spring or winter lead to the coldest temperatures at night," Scambos said. "The thing is, here in the United States and most of Canada, we don't get a night that lasts three or four or six months long for things to really chill down under extended clear sky conditions."

Centuries-old ice cracks

Scambos and his team spotted the record low temperatures while working on a related study on unusual cracks on East Antarctica's ice surface that he suspects are several hundred years old.

"The cracks are probably thermal cracks -- the temperature gets so low in winter that the upper layer of the snow actually shrinks to the point that the surface cracks in order to accommodate the cold and the reduction in volume," Scambos said. "That led us to wonder what the temperature range was. So, we started hunting for the coldest places using data from three satellite sensors."

More than 30 years of data from the Advanced Very High Resolution Radiometer (AVHRR) on the NOAA Polar Orbiting Environmental Satellite (POES) series gave Scambos a good perspective on what the pattern of low temperatures looked like across Antarctica.

"Landsat 8 is still a new sensor, but preliminary work shows its ability to map the cold pockets in detail," Scambos said. "It's showing how even small hummocks stick up through the cold air."

Scambos suspected they would find one area that got extremely cold. Instead they found a large strip at high altitude where several spots regularly reach record low temperatures. Furthermore, dozens of these extremely cold areas reached about the same minimum temperatures of -92 to -94 degrees Celsius (-134 to -137 degrees Fahrenheit) on most years.

"This is like saying that on the coldest day of the year a whole strip of land from International Falls, Minnesota to Duluth, Minnesota to Great Falls, Montana reached the exact same temperature, and more than once," Scambos said. "And that's a little odd."

A physical limit

The scientists suspect that a layer in the atmosphere above the ice plateau reaches a certain minimum temperature and is preventing the ice plateau's surface from getting any colder.

"There seems to be a physical limit to how cold it can get in this high plateau area and how much heat can escape," Scambos said. Although an extremely cold place, Antarctica's surface radiates heat or energy out into space, especially when the atmosphere is dry and free of clouds.

"The levels of carbon dioxide, nitrogen oxide, traces of water vapor and other gases in the air may impose a more or less uniform limit on how much heat can radiate from the surface," Scambos said.

Scambos and his team will continue to refine their map of Earth's coldest places using Landsat 8 data. "It's a remarkable satellite and we've repeatedly been impressed with how well it works, not just for mapping temperature but for mapping crops and forests and glaciers all over the world," Scambos said.

"The uses for Landsat 8 data are broad and diverse," said James Irons, Landsat 8 project scientist at NASA's Goddard Space Flight Center in Greenbelt, Md. "And Scambos' work is an example of some of the intriguing science that can be done using Landsat 8."

In the longer term, Scambos and his team will try to design weather stations and set them up in the area where the record temperatures occur to confirm the data from Landsat 8 and MODIS. Currently, most of the automated weather stations in the vicinity do not work properly in the dead of winter.

"The research bases there don't have people that stay through the winter to make temperature measurements," Scambos said. "We will need to investigate electronics that can survive those temperatures."

View the NASA animation The Coldest Place in the World: http://www.youtube.com/watch?v=Hp6wMUVb23c


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Deaths attributed directly to climate change cast pall over penguins

Climate change is killing penguin chicks from the world's largest colony of Magellanic penguins, not just indirectly -- by depriving them of food, as has been repeatedly documented for these and other seabirds -- but directly as a result of drenching rainstorms and, at other times, heat, according to new findings from the University of Washington.

Too big for parents to sit over protectively, but still too young to have grown waterproof feathers, downy penguin chicks exposed to drenching rain can struggle and die of hypothermia in spite of the best efforts of their concerned parents. And during extreme heat, chicks without waterproofing can't take a dip in cooling waters as adults can.

Various research groups have published findings on the reproductive repercussions from single storms or heat waves, events that individually are impossible to tie to climate change. The new results span 27 years of data collected in Argentina under the direction of Dee Boersma, UW biology professor, with the support of the Wildlife Conservation Society, the UW, the Office of Turismo in Argentina's Chubut Province, the Global Penguin Society and the La Regina family. Boersma is lead author of a paper on the findings in the Jan. 29 issue of PLOS ONE.

"It's the first long-term study to show climate change having a major impact on chick survival and reproductive success," said Boersma, who has led field work since 1983 at the world's largest breeding area for Magellanic penguins, about halfway up the Atlantic coast of Argentina at Punta Tombo, where 200,000 pairs reside from September through February to have their young.

During a span of 27 years, an average of 65 percent of chicks died per year, with some 40 percent starving. Climate change, a relatively new cause of chick death, killed an average of 7 percent of chicks per year, but there were years when it was the most common cause of death, killing 43 percent of all chicks one year and fully half in another.

Starvation and weather will likely interact increasingly as climate changes, Boersma said.

"Starving chicks are more likely to die in a storm," she said. "There may not be much we can do to mitigate climate change, but steps could be taken to make sure the Earth's largest colony of Magellanic penguins have enough to eat by creating a marine protected reserve, with regulations on fishing, where penguins forage while raising small chicks."

Rainfall and the number of storms per breeding season have already increased at the Argentine study site, said Ginger Rebstock, UW research scientist and the co-author of the paper. For instance in the first two weeks of December, when all chicks are less than 25 days old and most vulnerable to storm death, the number of storms increased between 1983 and 2010.

"We're going to see years where almost no chicks survive if climate change makes storms bigger and more frequent during vulnerable times of the breeding season as climatologists predict," Rebstock said.

Magellanics are medium-sized penguins standing about 15 inches tall and weighing about 10 pounds. Males of the species sound like braying donkeys when they vocalize. Of the Earth's 17 species of penguins, 10 -- including Magellanics -- breed where there is no snow, it is relatively dry and temperatures can be temperate.

Punta Tombo is so arid that it gets an average of only 4 inches (100 mm) of rain during the six-month breeding season and, sometimes, no rain falls at all. Rain is a problem and kills down-covered chicks ages 9 to 23 days if they can't warm up and dry off after heavy storms in November and December when temperatures are likely to dip. If chicks can live 25 days or more, most have enough juvenile plumage to protect them. Once chicks die, parents do not lay additional eggs that season.

The findings are based on weather information, collected at the regional airport and by researchers in the field, as well as from penguin counts. During the breeding season researchers visit nests once or twice a day to see what is happening and record the contents of the nest, often hunting for chicks when they move around as they get older. When chicks disappear or are found dead, the researchers turn into detectives looking for evidence of starvation, predators or other causes of death such as being pecked or beaten by other penguins.

Just back from two months in the field, Boersma said heat this season took a greater toll on chicks than storms. Such variability between years is the reason why the number of chicks dying from climate change is not a tidy, ever-increasing figure each year. Over time, however, the researchers expect climate change will be an increasingly important cause of death.

Also contributing to increasing deaths from climate change is the fact that, over 27 years, penguin parents have arrived to the breeding site later and later in the year, probably because the fish they eat also are arriving later, Boersma said. The later in the year chicks hatch the more likely they'll still be in their down-covered stage when storms typically pick up in November and December.

Besides the coast of Argentina, Magellanic penguins also breed on the Chile-side of South America and in the Falkand (Malvinas) Islands, breeding ranges they share with some 60 other seabird species. These species also are likely to suffer negative impacts from climate change, losing whole generations as the penguins have in the study area, the co-authors say.

"Increasing storminess bodes ill not only for Magellanic penguins but for many other species," they write.


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Better climate predictions for West Africa

The population of West Africa is growing rapidly. It has to cope with a complex meteorology, unreliable climate prognoses, and increasing air pollution. Within the next five years, extensive measurements will be accomplished in this region, new weather and climate models will be developed, and development policy is planned to be supported under the DACCIWA EU project. DACCIWA covers the complete chain from natural and anthropogenic emissions to impacts on the climate, ecosystems, and health. The project coordinated by KIT has a budget of nearly nine million euros.

Due to the highest population growth worldwide, massive urbanization, and a stable economic growth, countries in southern West Africa currently are exposed to rapid change. The quickly growing major cities are mainly located on the coast, agricultural production areas and forests can be found directly behind. In the cities, the emissions caused by man are increasing strongly. Among others, these emissions are caused by road traffic due to a largely outdated vehicle technology. As a result of the increasing fine dust pollution, people in the cities are increasingly suffering from respiratory diseases. High ozone concentrations typically occur outside of the cities and represent a risk factor for the health of rural population as well as for agricultural production.

According to the recent World Bank report, West Africa is among the regions that will be affected most by global climate change. Climatic impacts resulting from the massive conversion of natural forests into agricultural areas are accompanied by a change of regional climate. It has hardly been studied so far and is caused by anthropogenic emissions from the combustion of fossil fuels and biomass combined with natural emissions of plants. Formation of solid and liquid aerosol particles is increased. These aerosol particles act as condensation nuclei and modify cloud formation. "We assume that increased cloud formation affects the complete monsoon system," Professor Peter Knippertz of the Institute of Meteorology and Climate Research (IMK) of KIT explains. "These relationships have hardly been studied for West Africa so far." Improved climate prognosis for West Africa will also affect regions located far away. "We know, for example, that the West African monsoon interacts with the Indian monsoon and also represents a major parameter influencing Atlantic hurricanes."

Within the framework of DACCIWA, the researchers will first compile current data in an extensive measurement campaign with satellites, aircraft, and ground-based instruments. With the help of the resulting dataset and numerous modeling activities, all relevant physical and chemical processes, such as emission, cloud formation, solar irradiation, precipitation, regional air circulation, climate, and health, will be understood much better. Work is aimed at developing a new generation of weather and climate models, predicting heavy monsoon rains, and better prognosticating climate change. "The findings obtained under DACCIWA will be transferred to other monsoon regions and highly valuable for development policy," Professor Knippertz says.

Professor Knippertz coordinates the new interdisciplinary project DACCIWA (Dynamics-aerosol-chemistry-cloud interactions in West Africa) that started on December 01, 2013 and will have a duration of four and a half years. The project is funded by the EU under the 7th Framework Programme with EUR 8.75 million. Of these funds, 1.88 million go to KIT. 16 scientific institutions from Germany, Switzerland, France, Great Britain, Ghana, Nigeria as well as additional partners from Benin and the Ivory Coast are involved in DACCIWA. One of the German partners is the German Aerospace Center (DLR). Activities will focus on the investigation of the interactions of aerosols and clouds.

Together with two other projects, DACCIWA makes up the European Research Cluster "Aerosols and Climate." The cluster started in December. Information on the Research Cluster and on the kickoff event is available at http://www.aerosols-climate.org.

Link to the report of the World Bank: http://climatechange.worldbank.org/sites/default/files/Turn_Down_the_heat_Why_a_4_degree_centrigrade_warmer_world_must_be_avoided.pdf


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Antarctica's Pine Island Glacier sensitive to climatic variability

A new study published in Science this month suggests the thinning of Pine Island Glacier in West Antarctica is much more susceptible to climatic and ocean variability than at first thought. Observations by a team of scientists at British Antarctic Survey, and other institutions, show large fluctuations in the ocean heat in Pine Island Bay. The team discovered that oceanic melting of the ice shelf into which the glacier flows decreased by 50 per cent between 2010 and 2012, and this may have been due to a La Nin? weather event.

Pine Island Glacier has thinned continuously during past decades driven by an acceleration in its flow. The acceleration is thought to be caused by thinning of the floating ice shelf created as the glacier slides into the sea. Understanding the processes driving ice shelf thinning and the glacier's response is key to assessing how much it will contribute to rising sea levels.

It's now known that much of the thinning is due to a deep oceanic inflow of Circumpolar Deep Water (CDW) on the continental shelf neighbouring the glacier. This warmer water then makes its way into a cavity beneath the ice shelf melting it from below.

The passage of this warmer water was made easier by the unpinning of the ice shelf from an underwater ridge. The ridge had, in effect, acted as a wall preventing warmer water from getting to the thickest part of the shelf. This ungrounding event was one of the major driving forces behind the glacier's rapid change.

In 2009, a higher CDW volume and temperature in Pine Island Bay contributed to an increase in ice shelf melting compared to the last time measurements were taken in 1994. But observations made in January 2012, and reported now in Science, show that ocean melting of the glacier was the lowest ever recorded. The top of the thermocline (the layer separating cold surface water and warm deep waters) was found to be about 250 metres deeper compared with any other year for which measurements exist.

This lowered thermocline reduces the amount of heat flowing over the ridge. High resolution simulations of the ocean circulation in the ice shelf cavity demonstrate that the ridge blocks the deepest ocean waters from reaching the thickest ice. So its presence enhances the ice shelf's sensitivity to climate variability since any changes in the thermocline can alter the amount of heat filtering through.

The fluctuations in temperature recorded by the team may be explained by particular climatic conditions. In January 2012 the dramatic cooling of the ocean around the glacier is believed to be due to an increase in easterly winds caused by a strong La Nin? event in the tropical Pacific Ocean. Normally the winds flow from the west.

The observations suggest there is a complex interplay between geological, oceanographic and climatic processes. The study stresses the importance of both local geology and climate variability in ocean melting in this region.

Lead author, Dr Pierre Dutrieux, from British Antarctic Survey (BAS) said: "We found ocean melting of the glacier was the lowest ever recorded, and less than half of that observed in 2010. This enormous, and unexpected, variability contradicts the widespread view that a simple and steady ocean warming in the region is eroding the West Antarctic Ice Sheet. These results demonstrate that the sea-level contribution of the ice sheet is influenced by climatic variability over a wide range of time scales."

Co-author, Professor Adrian Jenkins, also from BAS, added: "It is not so much the ocean variability, which is modest by comparison with many parts of the ocean, but the extreme sensitivity of the ice shelf to such modest changes in ocean properties that took us by surprise. That sensitivity is a result of a submarine ridge beneath the ice shelf that was only discovered in 2009 when an Autonomous Underwater Vehicle mapped the seabed beneath the ice. These new insights suggest that the recent history of ice shelf melting and thinning has been much more variable than hitherto suspected and susceptible to climate variability driven from the tropics."


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Walden Pond trees leafing out far earlier than in Thoreau's time

Climate-change studies by Boston University biologists show leaf-out times of trees and shrubs at Walden Pond are an average of 18 days earlier than when Henry David Thoreau made his observations there in the 1850s. However, not all plants respond in the same way, the result of which is that native species eventually may be threatened and lose competitive advantage to more resilient invasive shrubs such as Japanese barberry, according to a study published in the new edition of New Phytologist.

"By comparing historical observations with current experiments, we see that climate change is creating a whole new risk for the native plants in Concord," said BU Prof. Richard Primack. "Weather in New England is unpredictable, and if plants leaf out early in warm years, they risk having their leaves damaged by a surprise frost. But if plants wait to leaf out until after all chance of frost is lost, they may lose their competitive advantage."

The study began when Caroline Polgar, a graduate student with Primack, examined Thoreau's unpublished observations of leaf-out times for common trees and shrubs in Concord in the 1850s, then repeated his observations over the past five springs.

"We started to wonder if all trees and shrubs in Concord are equally responsive to warming temperatures in the spring," Polgar said. What she found was surprising. "All species -- no exceptions -- are leafing out earlier now than they did in Thoreau's time," she said. "On average, woody plants in Concord leaf out 18 days earlier now."

In New England, plants have to be cautious about leafing out in the early spring. If they leaf out too early, their young leaves could suffer from subsequent late frost. Since leafing-out requirements are thought to be species-specific, the group designed a lab experiment to test the responsiveness of 50 tree and shrub species in Concord to warming temperatures in the late winter and early spring.

For the past two winters, the researchers traveled to Concord and collected leafless dormant twigs from each species, and placed them in cups of water in their lab. Over the following weeks, they observed how quickly each species was be able produce their leaves in these unseasonably warm lab conditions.

"We found compelling evidence that invasive shrubs, such as Japanese barberry, are ready to leaf out quickly once they are exposed to warm temperatures in the lab even in the middle of winter, whereas native shrubs, like highbush bluberry, and native trees, like red maple, need to go through a longer winter chilling period before they can leaf out -- and even then their response is slow," says Amanda Gallinat, a second-year graduate student and third author of the paper.

The strength of this study, Gallinat said, is the pairing of observations and experiments.

"Our current observations show that plants in Concord today are leafing out earlier than in Thoreau's time in response to warm temperatures," she said. "However, the experiments show that as spring weather continues to warm, it will be the invasive shrubs that will be best able to take advantage of the changing conditions."

The spring growing season is of increasing interest to biologists studying the effects of a warming climate, and in coming decades non-native invasive shrubs are positioned to win the gamble on warming temperature, Primack said. The BU group is adding these findings to a growing list of advancing spring phenomena in Concord and elsewhere in Massachusetts, including flowering dates, butterfly flight times, and migratory bird arrivals. Founded in 1839, Boston University is an internationally recognized institution of higher education and research. With more than 33,000 students, it is the fourth-largest independent university in the United States. BU consists of 16 schools and colleges, along with a number of multi-disciplinary centers and institutes integral to the University's research and teaching mission. In 2012, BU joined the Association of American Universities (AAU), a consortium of 62 leading research universities in the United States and Canada.


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Air pollution from Asia affecting world's weather

Extreme air pollution in Asia is affecting the world's weather and climate patterns, according to a study by Texas A&M University and NASA's Jet Propulsion Laboratory researchers.

Yuan Wang, a former doctoral student at Texas A&M, along with Texas A&M atmospheric sciences professors Renyi Zhang and R. Saravanan, have had their findings published in the current issue of Nature Communications.

Using climate models and data collected about aerosols and meteorology over the past 30 years, the researchers found that air pollution over Asia -- much of it coming from China -- is impacting global air circulations.

"The models clearly show that pollution originating from Asia has an impact on the upper atmosphere and it appears to make such storms or cyclones even stronger," Zhang explains.

"This pollution affects cloud formations, precipitation, storm intensity and other factors and eventually impacts climate. Most likely, pollution from Asia can have important consequences on the weather pattern here over North America."

China's booming economy during the last 30 years has led to the building of enormous manufacturing factories, industrial plants, power plants and other facilities that produce huge amounts of air pollutants. Once emitted into the atmosphere, pollutant particles affect cloud formations and weather systems worldwide, the study shows.

Increases in coal burning and car emissions are major sources of pollution in China and other Asian countries.

Air pollution levels in some Chinese cities, such as Beijing, are often more than 100 times higher than acceptable limits set by the World Health Organization standards, Zhang says.

One study has shown that lung cancer rates have increased 400 percent in some areas due to the ever-growing pollution problem.

Conditions tend to worsen during winter months when a combination of stagnant weather patterns mixed with increased coal burning in many Asian cities can create pollution and smog that can last for weeks. The Chinese government has pledged to toughen pollution standards and to commit sufficient financial resources to attack the problem. "The models we have used and our data are very consistent with the results we have reached," Saravanan says.

"Huge amounts of aerosols from Asia go as high as six miles up in the atmosphere and these have an unmistakable impact on cloud formations and weather."

Zhang adds that "we need to do some future research on exactly how these aerosols are transported globally and impact climate. There are many other atmospheric observations and models we need to look at to see how this entire process works."

Yuan Wang, who conducted the research with Zhang while at Texas A&M, currently works at NASA's Jet Propulsion Laboratory as a Caltech Postdoctoral Scholar.

The study was funded by grants from NASA, Texas A&M's Supercomputing facilities and the Ministry of Science and Technology of China.


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Hot weather deaths projected to rise 257 percent in UK by 2050s, experts warn

The number of annual excess deaths caused by hot weather in England and Wales is projected to surge by 257% by the middle of the century, as a result of climate change and population growth, concludes research published online in the Journal of Epidemiology and Community Health.

The elderly (75+) will be most at risk, particularly in the South and the Midlands, the findings suggest.

The research team, from the London School of Hygiene and Tropical Medicine, and Public Health England, used time-series regression analysis to chart historic (1993-2006) fluctuations in weather patterns and death rates to characterise the associations between temperature and mortality, by region and by age group.

They then applied these to projected population increases and local climate to estimate the future number of deaths likely to be caused by temperature -- hot and cold -- for the 2020s, 2050s, and 2080s.

They based their calculations on the projected daily average temperatures for 2000-09, 2020-29, 2050-59 and 2080-89, derived from the British Atmospheric Data Centre (BADC), and population growth estimates from the Office of National Statistics.

The calculations indicated a significantly increased risk of deaths associated with temperature across all regions of the UK, with the elderly most at risk.

The number of hot weather days is projected to rise steeply, tripling in frequency by the mid 2080s, while the number of cold days is expected to fall, but at a less dramatic pace.

At the national level, the death rate increases by just over 2% for every 1?C rise in temperature above the heat threshold, with a corresponding 2% increase in the death rate for every 1?C fall in temperature below the cold threshold.

In the absence of any adaptive measures, excess deaths related to heat would be expected to rise by 257% by the 2050s, from an annual baseline of 2000, while those related to the cold would be expected to fall by 2% as a result of milder winters, from a current toll of around 41,000, but will still remain significant.

Those aged 85 and over will be most at risk, partly as a result of population growth -- projected to reach 89 million by the mid 2080s -- and the increasing proportion of elderly in the population, say the authors.

Regional variations are likely to persist: London and the Midlands are the regions most vulnerable to the impact of heat, while Wales, the North West, Eastern England and the South are most vulnerable to the impact of cold.

Rising fuel costs may make it harder to adapt to extremes of temperature, while increased reliance on active cooling systems could simply end up driving up energy consumption and worsening the impact of climate change, say the authors.

Better and more sustainable options might instead include shading, thermal insulation, choice of construction materials implemented at the design stage of urban developments, suggest the authors.

While the death toll from cold weather temperatures will remain higher than that caused by hot temperatures, the authors warn that health protection from hot weather will become increasingly necessary -- and vital for the very old.

"As the contribution of population growth and aging on future temperature related health burdens will be large, the health protection of the elderly will be important," warn the authors, recalling the social changes that have led to many elderly living on their own -- a contributory factor to the high death toll in France in the 2003 heatwave.


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North Atlantic atmospheric oscillation affects quality of cava

The quality of cava depends on technical factors such as fermentation, aging and bottling processes, which usually remain stable for years. Researchers from Malaga University (Spain) have discovered that oscillations in the North Atlantic -that affects European climate- also have an effect on the attributes of this sparkling wine. The years in which there is presence of the Azores anticyclone, there is a drop in the quality of cava.

The researchers Raimundo Real and Jos? Carlos B?ez, from the University of Malaga, have analysed the possible effects of the North Atlantic oscillation, known in scientific literature as NAO, on the quality of Spanish cava in a study published in the International Journal of Biometeorology.

The NAO is a microclimate index that reflects the atmospheric pressure difference between the Azores and Iceland, so the presence of an anticyclone in the Azores is positive and it is negative if there are areas of low pressure in that same area. This pressure difference that oscillates over time, has a direct effect on the weather conditions in the Iberian Peninsula.

"We discovered there was a connection between the NAO and the quality of cava between 1970 and 2008. The existence of positive NAO values during the months of March to August, when the grape is developing and maturing, reduced the capacity of obtaining top quality cava," Raimundo Real told SINC.

The North Atlantic oscillation plays a major role in weather fluctuations in the hemisphere. The phenomenon affects the climate in Europe and the Iberian Peninsula. It is related to temperature and rain variations in cava producing regions, which affects the physiological processes during the grape's period of maturity.

"The likelihood of obtaining a top quality cava is higher when the average value of the NAO is negative. This makes the average temperature in the cava region drop and the quality improves," the expert explained.

Inter-annual variations in the quality of cava are determined according to the different aromas and the amount of sugar in the grape. These qualities of the plant in turn, in one area of production, depend on weather conditions, such as cloud cover, temperature and rainfall to which the plant is subjected, particularly during the grape period (March to September).

Predicting the years of top-quality cava

The climate in the Atlantic Ocean, the Mediterranean basin and the surrounding continents shows considerable weather variability.

"During half of the years we analysed, the NAO values are intermediate and do not clearly affect the quality of the cava, but in the other half, the values are more extreme and lead to clearly favorable or unfavorable conditions for obtaining top-quality," says Real.

The information for 2012 pointed towards an 80% likelihood of obtaining a top-quality cava, while this likelihood is around 45% for 2013, always according to the model obtained. The model correctly predicted the 80% for the clearly favorable years for obtaining top-quality cava and the 70% likelihood of the clearly unfavorable years.

The NAO value between March and August can be calculated in the actual wine harvest time, while the quality of the cava can only be valued two years later. "This is important for being able to predict years of top-quality cava production, as well as for exploring the possible effects and variations of climate change on the quality" he concluded.


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Researchers target sea level rise to save years of archaeological evidence

Prehistoric shell mounds found on some of Florida's most pristine beaches are at risk of washing away as the sea level rises, wiping away thousands of years of archaeological evidence.

"The largest risk for these ancient treasure troves of information is sea level rise," said Shawn Smith, a senior research associate with the Center for Ocean-Atmospheric Prediction Studies at Florida State University.

But a joint project between Smith and the National Park Service is drawing attention to the problem to hopefully minimize the impact on the state's cultural sites.

Smith and Margo Schwadron, an archaeologist with the National Park Service, have embarked on a project to examine past and future changes in climate and how we can adapt to those changes to save areas of shoreline and thus preserve cultural and archeological evidence.

"We're kind of the pioneers in looking at the cultural focus of this issue," Smith said, noting that most weather and ocean experts are concerned about city infrastructure for coastal areas.

To complete the project, the National Park Service awarded Smith a $30,000 grant. With that money, Smith and former Florida State University undergraduate Marcus Johnson spent hours compiling modern, colonial and paleo weather data.

The focus of their initial research is the Canaveral National Seashore and Everglades National Park, which both have prehistoric shell mounds, about 50 feet to 70 feet high. Researchers believe these shell mounds served as foundations for structures and settlements and later served as navigational landmarks during European exploration of the region.

Modern temperature and storm system information was easily available to researchers. But, to go hundreds and then thousands of years back took a slightly different approach.

Log books from old Spanish forts as well as ships that crossed the Atlantic had to be examined to find the missing information.

The result was a comprehensive data set for the region, so detailed that modern era weather conditions are now available by the hour.

Smith and Schwadron are trying to secure more funding to continue their work, but for now, they are making their data set available to the general public and other researchers in hopes of raising awareness about the unexpected effects of sea level rise.

The National Park Service has also published a brochure on climate change and the impact that sea level rise could have on the shell mounds found at Cape Canaveral.


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Use of media can save lives in bad storms

The number and intensity of storms and other extreme weather events are on the increase all over the world. The latest study by the Medical University of Vienna in cooperation with the US Centers for Disease Control and Prevention (CDC) uses the example of one of the largest American series of tornados of all times to show that the risk of injury can be reduced significantly with the use of certain media.

Several dozen tornados struck in April 2011 across Southeast USA and made for an image of devastation. Thomas Niederkrotenthaler from the Centre for Public Health of the Medical University of Vienna used this third-largest series of tornados in the history of the USA as an opportunity to conduct a study, which just appeared in the latest edition of the international top journal PLOS ONE.

Television and social media offer particularly good protection

Together with his research team, Niederkrotenthaler investigated the behavioral factors which reduce or increase the risk of injury. The researchers particularly concentrated on the media use by those affected, which had never been scientifically investigated in this context so far. The results of the study show that people who used media intensively for education during the series of tornados, had a significantly less risk of injury. Television and Internet were mainly protective and warnings via social media such as Twitter and Facebook particularly in this case.

"The media carried out excellent work. It accurately predicted the streets and the locations through which the tornados would pass, and continuously provided information about changes in the predictions. The corresponding media users could thus effectively protect themselves from the consequences of the storms," says Niederkrotenthaler. "The great protective effect of media has its cause in an important characteristic feature of tornados because unlike hurricanes, its exact course can only be predicted shortly before its arrival. The target forecast lead time of the US National Weather Service is just 15 minutes."

Adapting the US prevention guidelines on the basis of the Medical University of Vienna/CDC study

The media is however also important for another reason: Approximately 20 percent of the injuries are caused only after a tornado, mainly during the cleaning-up operations. Toppling trees and accidents with chain saws are especially dangerous and rather frequent. This was an outcome that led to an adaptation of the American prevention guidelines. Niederkrotenthaler also says: "The tornado prevention guidelines were adapted as an outcome of our study. The media now informs the citizens that they need to be particularly careful after tornados as well."

The internationally composed research team identified a visit to shelters and cellar rooms as another important protective factor. Niederkrotenthaler said, "As a whole, factors of primary prevention mainly save lives in such cases. In Alabama alone there were 212 deaths due to the tornado outbreak; however, most of the victims did not make it to a hospital, which emphasizes the relevance of primary prevention." Tornado sirens also correspondingly made a significant contribution to protecting the civil population. They did sound quite frequently because of false alarms, but those affected have surprisingly not become hardened because of that -- on the contrary: "People, who had already heard the sirens before when a tornado actually struck, protected themselves better than others even during the series of tornados which we investigated," says Niederkrotenthaler.

Journal Reference:

Thomas Niederkrotenthaler, Erin M. Parker, Fernando Ovalle, Rebecca E. Noe, Jeneita Bell, Likang Xu, Melissa A. Morrison, Caitlin E. Mertzlufft, David E. Sugerman. Injuries and Post-Traumatic Stress following Historic Tornados: Alabama, April 2011. PLoS ONE, 2013; 8 (12): e83038 DOI: 10.1371/journal.pone.0083038

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With few hard frosts, tropical mangroves push north

Cold-sensitive mangrove forests have expanded dramatically along Florida's Atlantic Coast as the frequency of killing frosts has declined, according to a new study based on 28 years of satellite data from the University of Maryland and the Smithsonian Environmental Research Center in Edgewater, Md.

Between 1984 and 2011, the Florida Atlantic coast from the Miami area northward gained more than 3,000 acres (1,240 hectares) of mangroves. All the increase occurred north of Palm Beach County. Between Cape Canaveral National Seashore and Saint Augustine, mangroves doubled in area. Meanwhile between the study's first five years and its last five years, nearby Daytona Beach recorded 1.4 fewer days per year when temperatures fell below 28.4 degrees Fahrenheit (-4 degrees Celsius). The number of killing frosts in southern Florida was unchanged.

The mangroves' march up the coast as far north as St. Augustine, Fla., is a striking example of one way climate change's impacts show up in nature. Rising temperatures lead to new patterns of extreme weather, which in turn cause major changes in plant communities, say the study's authors.

Unlike many studies which focus on changes in average temperatures, this study, published online Dec. 30 in the peer-reviewed journal Proceedings of the National Academy of Sciences, shows that changes in the frequency of rare, severe events can determine whether landscapes hold their ground or are transformed by climate change.

The mangrove forests are edging out salt marshes, said University of Maryland Entomology Professor Daniel S. Gruner, a study co-author. "This is what we would expect to see happening with climate change, one ecosystem replacing another," said Gruner, who co-leads an interdisciplinary research project on mangrove ecosystems, along with Ilka C. Feller of the Smithsonian. "But at this point we don't have enough information to predict what the long term consequences will be."

One valuable ecosystem replaces another -- at what cost?

"Some people may say this is a good thing, because of the tremendous threats that mangroves face," said the study's lead author, Kyle Cavanaugh, a Smithsonian postdoctoral research fellow. "But this is not taking place in a vacuum. The mangroves are replacing salt marshes, which have important ecosystem functions and food webs of their own."

Mangrove forests grow in calm, shallow coastal waters throughout the tropics. Salt marshes fill that niche in temperate zones. Both provide crucial habitat for wildlife, including endangered species and commercially valuable fish and shellfish. Some animals use both types of habitat. Others, like marsh-nesting seaside sparrows or the honey bees that produce mangrove honey, rely on one or the other.

Both provide valuable ecosystem services, buffering floods, storing atmospheric carbon and building soils. Both are in decline nationally and globally. Mangrove forests are cut down for charcoal production, aquaculture and urbanization or lose habitat to drainage projects. Salt marshes are threatened by drainage, polluted runoff and rising sea levels.

Florida naturalists noticed that mangroves now grow in places that once were too chilly for the tropical trees. "We knew this was happening, but no one knew if it was a local or a regional phenomenon," Cavanaugh said.

Study used satellite photos, the "gold standard" in climate change

Cavanaugh, an expert in remote sensing, turned to photographs of Florida's Atlantic coast taken by NASA's Landsat 5, which launched in 1984 and tracked changes in Earth's land cover until 2011. "It very quickly became a gold standard to examine the effects of climate change, because it lets you look back in time," Cavanaugh said.

The satellite images revealed the mangroves' expansion into terrain formerly inhabited by salt marsh plants. While the study only looked at the Atlantic Coast, the same trend is taking place on Florida's Gulf Coast, Cavanaugh and Gruner said.

Mean winter temperatures have risen at seven of eight coastal weather stations in the study area. But if overall warming benefited mangroves, the mangrove cover should have increased all over Florida, not only in the north. Average winter temperature, rainfall, and urban or agricultural land use did not explain the mangroves' expansion. Only fewer freezing days at the northern end of their range matched the trend.

The researchers are studying effects on coastal insects and birds; whether the change will affect coastal ecosystems' ability to store carbon; and whether juvenile fish and commercially valuable shellfish will remain abundant in the changing plant communities.

Cavanaugh is looking at Landsat 5 imagery for Mexico, Peru, Brazil, Australia and New Zealand to see if mangroves are expanding elsewhere as they are in Florida.


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First infrared satellite monitoring of peak pollution episodes in China

Plumes of several anthropogenic pollutants (especially particulate matter and carbon monoxide) located near ground level over China have for the first time been detected from space. The work was carried out by a team at the Laboratoire Atmosph?res, Milieux, Observations Spatiales (CNRS / UPMC / UVSQ) in collaboration with Belgian researchers and with support from CNES, using measurements by the IASI infrared sounder launched on board the MetOp satellite. Their groundbreaking results are published online on the website of the journal Geophysical Research Letters dated 17 January 2014. They represent a crucial step towards improved monitoring of regional pollution and forecasting of local pollution episodes, especially in China.

Despite efforts by the Chinese government to reduce surface emissions, China is repeatedly affected by major air pollution episodes. This has become an important public health issue, since air pollution causes more than 300,000 premature deaths in China each year. In January 2013, Beijing suffered an unprecedented pollution episode, mainly due to seasonal coal consumption and unfavorable weather conditions (lack of wind plus temperature inversion) that trapped the pollutants at ground level. In many regions, atmospheric concentrations of particulate matter (PM) reached values considered harmful to human health, sometimes exceeding the daily threshold recommended by the World Health Organization (25 ?g/m3) by a factor of nearly 40.

To monitor local and regional pollution, China has an air quality monitoring network that continuously provides measurements of key pollutants including PM, carbon monoxide (CO) and sulfur dioxide (SO2). However, the geographical distribution of measuring stations is patchy, which makes it difficult to predict the development of pollution episodes. In this context, satellite observations prove to be extremely valuable due to their excellent geographical coverage and horizontal resolution. Unfortunately, such measurements have the disadvantage of being sensitive principally at altitudes of 3 to 10 km. Using satellites to determine atmospheric composition near ground level was complicated until now.

The researchers have shown that, contrary to expectations, the IASI sounder is able to detect plumes of pollutants even near ground level as long as two conditions are met: weather conditions must be stable, which leads to a build-up of pollutants at ground level, and there must be a significant temperature difference between the ground and the air just above Earth's surface. In January 2013, IASI measured very high concentrations of anthropogenic pollutants such as CO, SO2, ammonia (NH3) and ammonium sulfate aerosols over Beijing and neighboring cities. The IASI infrared sounder thus proves to be well suited to monitoring these pollutants in such conditions.

This work represents a breakthrough in pollution monitoring from space. With the launch of IASI-B, two IASI sounders are now able to collect infrared data from space and twice as much information has therefore been available since the end of January 2013. It will henceforth be possible to monitor pollution episodes associated with stable weather conditions more accurately and regularly. The work opens up new prospects for improved assessment and management of air quality.


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World temperature records available via Google Earth

Climate researchers at the University of East Anglia have made the world's temperature records available via Google Earth.

The Climatic Research Unit Temperature Version 4 (CRUTEM4) land-surface air temperature dataset is one of the most widely used records of the climate system.

The new Google Earth format allows users to scroll around the world, zoom in on 6,000 weather stations, and view monthly, seasonal and annual temperature data more easily than ever before.

Users can drill down to see some 20,000 graphs -- some of which show temperature records dating back to 1850.

The move is part of an ongoing effort to make data about past climate and climate change as accessible and transparent as possible.

Dr Tim Osborn from UEA's Climatic Research Unit said: "The beauty of using Google Earth is that you can instantly see where the weather stations are, zoom in on specific countries, and see station datasets much more clearly.

"The data itself comes from the latest CRUTEM4 figures, which have been freely available on our website and via the Met Office. But we wanted to make this key temperature dataset as interactive and user-friendly as possible."

The Google Earth interface shows how the globe has been split into 5? latitude and longitude grid boxes. The boxes are about 550km wide along the Equator, narrowing towards the North and South poles. This red and green checkerboard covers most of Earth and indicates areas of land where station data are available. Clicking on a grid box reveals the area's annual temperatures, as well as links to more detailed downloadable station data.

But while the new initiative does allow greater accessibility, the research team do expect to find errors.

Dr Osborn said: "This dataset combines monthly records from 6,000 weather stations around the world -- some of which date back more than 150 years. That's a lot of data, so we would expect to see a few errors. We very much encourage people to alert us to any records that seem unusual.

"There are some gaps in the grid -- this is because there are no weather stations in remote areas such as the Sahara. Users may also spot that the location of some weather stations is not exact. This is because the information we have about the latitude and longitude of each station is limited to 1 decimal place, so the station markers could be a few kilometres from the actual location.

"This isn't a problem scientifically because the temperature records do not depend on the precise location of each station. But it is something which will improve over time as more detailed location information becomes available."

This new initiative is described in a new research paper published on February 4 in the journal Earth System Science Data (Osborn T.J. and Jones P.D., 2014: The CRUTEM4 land-surface air temperature dataset: construction, previous versions and dissemination via Google Earth).

The CRUTEM4 data set is available from doi:10.5285/EECBA94F-62F9-4B7C-88D3-482F2C93C468.


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'Standing on a comet': Rosetta mission will contribute to space weather research

A comet-bound spacecraft that's been in sleep mode for more than two years is scheduled to wake up on the morning of Jan. 20 -- beginning the home stretch of its decade-long journey to a mile-wide ball of rock, dust and ice.

If all goes as planned, Rosetta -- a European Space Agency-led mission that involves University of Michigan engineers and scientists -- will be the first craft to actually land on a comet as well as track it for an extended period of time.

The Philae lander will latch on to the core of comet 67P/Churyumov-Gerasimenko in November and the orbiter will operate until the end of 2015. No mission has ever attempted such an in-depth look at one of these relics of the earliest days of our solar system.

Engineers at U-M's Space Physics Research Lab built electronic components for an onboard instrument that's believed to be the most sensitive of its kind ever flown in space. And a team of researchers will be involved in the mission science as well.

While most of the big questions Rosetta aims to answer deal with the origin and evolution of the solar system, U-M scientists will make a unique contribution that could provide very practical insights into how the sun and planets interface today.

They'll analyze measurements taken at the comet to study solar wind interactions that can lead to solar storms. The solar wind is a stream of charged particles emanating from the sun. Solar storms are bursts of activity that can threaten astronauts and damage Earth's satellites and electric grid.

"How the solar wind operates is one of the biggest outstanding questions about the solar system today. By studying how it interacts with cometary gases, we can learn a lot about the composition of the solar wind," said Tamas Gombosi, the Rollin M. Gerstacker Professor of Engineering in the Department of Atmospheric, Oceanic and Space Sciences.

Gombosi and his research group are leaders in the field of space weather. A model they developed was recently adopted by the national Space Weather Prediction Center.

At the sun's equator, the wind travels rather slowly, Gombosi said. It moves faster at high latitudes. Interactions between the two varieties can lead to magnetospheric storms. Earth orbits near the equator, so it's hard to study the fast wind from our vantage point.

"But comets pass through all of it. With their help, we can study the fast solar wind," Gombosi said.

Gombosi and other U-M researchers will be involved in additional Rosetta goals. They'll study and simulate how quickly the comet outgases material from its nucleus to its tail as it rings around the sun. They'll be involved in examining what elements are in the comet's tail, atmosphere and ionosphere, as well as how fast the electrified particles in the ionosphere are traveling.

Michael Combi, the Freeman Devold Miller Collegiate Research Professor in the Department of Atmospheric, Oceanic and Space Sciences, is a co-investigator on several instruments. He'll look into the rate at which the comet's core is sublimating, or turning from a solid into a gas, and he'll also work on a team that's analyzing those gases. They'll explore the levels of carbon monoxide and carbon dioxide, for example. They can't detect carbon dioxide from Earth.

"It's very difficult to observe some of the chemical species when they're far away and faint. Carbon dioxide is probably the second most abundant species at most comets, but it's not been observed in the thousands we've looked at from Earth," said Combi, who has studied comets for more than 30 years.

Comets -- small rock and ice bodies -- were present in the nebula that spawned the solar system and have been orbiting ever since in far away, cold belts either just past the orbit of Neptune or a quarter of the distance to the nearest star. For scientists, they're archeological artifacts that help them understand how the solar system formed and evolved. They're believed to have delivered Earth's oceans and perhaps the seeds of life in organic materials.

"People use the analogy that it's been in the freezer for the past 4.5 million years and brought in for convenient study. So we're looking as much as we can at the way the way the solar system was 4.5 billion years ago," Combi said.

Comet 67P/Churyumov-Gerasimenko is one of the smallest bodies humans have ever tried to land on. Its gravity is about 1,000 times less than that of Earth.

"On the lander, there's a camera that can look straight down like you're standing up and looking at the ground. Then there's a panoramic camera that can look out and see a picture of the horizon. It'll be fun to see what this landscape looks like," Combi said. "It'll be like standing on a comet."


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A whole new meaning to bad weather: Top ten worst weather places in the world

Have you ever wondered what places on Earth experience the worst weather? Ed Darack has. His article, "The 10 Worst Weather Places in the World," featured in this month's issue of Weatherwise magazineattempts to name the top ten places in the world that continually experience the most extreme weather. Inverting our fascination with "the grass is always greener" lists, (best beaches, places to live, vacation, etc.), Darack investigates the top ten places in the world with the worst weather.

Darack defines "bad" weather, what a "place" consists of, and the analysis of the conditions themselves. However, due to the lack of comprehensive global meteorological research, especially in the harshest climates where the risk to human life is significant, Darack relies on the available data and an effort to be objective.

Oymyakon, Republic of Sakha, Russian Siberia ranks number ten on the list. It has been recorded, although with dispute, that Oymyakon has reached the lowest temperature of Earth outside of Antarctica and the coldest permanently inhabited place at -89.9?F. On average, it drops to -50?F every night. Also, it is one of the places on the planet with the greatest annual swing rising to 86?F during the summer.

Number six on the list is Gandom-e Beryan, Dasht-e Lut, Iran, which is known for the hottest land surface temperature ever recorded. Using data from NASA's Earth Observing System's Aqua satellite, measuring the skin temperature of the planet, Gandom-e Beryan reached a staggering 159.3?F over the course of 2003-2009.

Next we visit the entire coastline of Antarctica, which stands at number three, not so much for the temperature, although extremely freezing, as for the storms. The driest continent meeting the world's most tumultuous ocean, the Southern Ocean, results in almost constant storms racing around the continent. In addition, extreme katabatic wind is also a factor. At Cape Dension in Commonwealth Bay in 1995 a wind speed of 129mph was measured. The highest wind speed ever recorded in Antarctica was 199mph.

Find out which other places made the list by accessing "The 10 Worst Weather Places in the World" free until the end of December 2013: http://www.weatherwise.org/Archives/Back%20Issues/2013/November-December%202013/10_worst_full.html

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First measurement flight: Research aircraft HALO explores trade wind clouds

Which climate effects do clouds have? Under what conditions do they warm or cool the atmosphere? Today, after more than five years of preparation, the specially equipped research aircraft HALO (High Altitude and Long Range Research Aircraft) takes off for its first measurement flight in atmospheric research. Prof. Bjorn Stevens and Dr. Lutz Hirsch from the Max Planck Institute for Meteorology (MPI-M) leave Oberpfaffenhofen in Germany for a ten-hour flight to Barbados.

They will operate numerous measuring instruments on board HALO on behalf of the German atmospheric research: "A day we have eagerly awaited," says Stevens. "It is the first major mission to exploit the novel capabilities of HALO to measure vertical profiles of all components of atmospheric water -- like vapor, liquid and ice, in both cloud and precipitation forms, as well as the aerosol particles upon which cloud droplets form -- from a high altitude. A new era of airborne atmospheric research." The aircraft, equipped with a large amount of advanced technology, is an initiative by German climate and environmental research institutions (see below) and is operated by the German Aerospace Center (DLR).

The flight is part of the NARVAL project (Next-generation Aircraft Remote-Sensing for Validation Studies) and will provide the scientists with more detailed information on the constitution of tropical clouds (Fig. 1). The transatlantic flights from Oberpfaffenhofen to Barbados will complement the stationary measurements of the cloud observatory on Barbados. The collected data will contribute to a better understanding of cloud and precipitation processes and will help to reduce uncertainties in climate models.

Remote sensing instruments, located in the "Belly Pod" underneath the aircraft?s hull, will detect vertical profiles of temperature and humidity and the distribution of droplets and aerosols (Fig. 2). Additionally, so-called dropsondes will be released during the flight. These radiosondes usually ascend from Earth with the help of a weather balloon and perform measurements on their way through the atmosphere. This time, they will be dropped by parachute and will glide back to the ground.

The first measurement flight is a joint project of the MPI-M with the Meteorological Institute of the University Hamburg, DLR, Universities of Cologne, Leipzig and Heidelberg and the Forschungszentrum J?lich. It will take the scientists on a long-haul flight to Barbados, where the MPI-M cloud observatory is located, and back. Ideally, comparison measurements with the satellite CloudSat will be performed during the flights. The satellite measures the Atlantic clouds in trajectories crosswise to the flight route. Short flights of HALO in parallel with these satellite trajectories make it possible to verify the satellite?s measurements (Fig. 3): the aircraft flies at a lower altitude than the satellite and can therefore detect the clouds much more accurate.

In total, the air route Oberpfaffenhofen -- Barbados and back should be flown three times in December 2013 ("NARVAL South"). During the second flight, a local flight from Barbados eastward through the trade wind clouds is planned. The aim is to detect clouds that are directly heading for the Barbados cloud observatory and to compare them to the land-based cloud observatory data.

The second part of the mission will be carried out under the direction of the University Hamburg in January ("NARVAL North"). HALO will be based on Iceland to examine the backsides of fronts over the North Atlantic. The amount of precipitation on the backsides of fronts is a controversial topic in science because satellite observations and model calculations provide different results. "Measured values are missing?? because ships do not sail in these typical storm zones" says principal investigator Prof. Felix Ament from the Center for Earth System Research and Sustainability (CEN), University of Hamburg. "A successful HALO mission could provide important facts and eliminate a 'blank spot' on the map of science."

The research aircraft HALO is an initiative by German climate and environmental research institutions. HALO is funded by: Federal Ministry of Education and Research (BMBF), German Research Foundation (DFG), Helmholtz Association, Max Planck Society, Leibniz Association, Free State of Bavaria, Karlsruhe Institute of Technology (KIT), GFZ German Research Centre for Geosciences, Forschungszentrum J?lich and German Aerospace Center (DLR)


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Arctic cyclones more common than previously thought

From 2000 to 2010, about 1,900 cyclones churned across the top of the world each year, leaving warm water and air in their wakes -- and melting sea ice in the Arctic Ocean.

That's about 40 percent more than previously thought, according to a new analysis of these Arctic storms.

A 40 percent difference in the number of cyclones could be important to anyone who lives north of 55 degrees latitude -- the area of the study, which includes the northern reaches of Canada, Scandinavia and Russia, along with the state of Alaska.

The finding is also important to researchers who want to get a clear picture of current weather patterns, and a better understanding of potential climate change in the future, explained David Bromwich, professor of geography at The Ohio State University and senior research scientist at the Byrd Polar Research Center.

The study was presented on Dec. 12 at the American Geophysical Union meeting, in a poster co-authored by his colleagues Natalia Tilinina and Sergey Gulev of the Russian Academy of Sciences and Moscow State University.

"We now know there were more cyclones than previously thought, simply because we've gotten better at detecting them," Bromwich said.

Cyclones are zones of low atmospheric pressure that have wind circulating around them. They can form over land or water, and go by different names depending on their size and where they are located. In Columbus, Ohio, for instance, a low-pressure system in December would simply be called a winter storm. Extreme low-pressure systems formed in the tropical waters can be called hurricanes or typhoons.

How could anyone miss a storm as big as a cyclone? You might think they are easy to detect, but as it turns out, many of the cyclones that were missed were small in size and short in duration, or occurred in unpopulated areas. Yet researchers need to know about all the storms that have occurred if they are to get a complete picture of storm trends in the region.

"We can't yet tell if the number of cyclones is increasing or decreasing, because that would take a multidecade view. We do know that, since 2000, there have been a lot of rapid changes in the Arctic -- Greenland ice melting, tundra thawing -- so we can say that we're capturing a good view of what's happening in the Arctic during the current time of rapid changes," Bromwich said.

Bromwich leads the Arctic System Reanalysis (ASR) collaboration, which uses statistics and computer algorithms to combine and re-examine diverse sources of historical weather information, such as satellite imagery, weather balloons, buoys and weather stations on the ground.

"There is actually so much information, it's hard to know what to do with it all. Each piece of data tells a different part of the story -- temperature, air pressure, wind, precipitation -- and we try to take all of these data and blend them together in a coherent way," Bromwich said.

The actual computations happen at the Ohio Supercomputer Center, and the combined ASR data are made publicly available to scientists.

Two such scientists are cyclone experts Tilinina and Gulev, who worked with Bromwich to look for evidence of telltale changes in wind direction and air pressure in the ASR data. They compared the results to three other data re-analysis groups, all of which combine global weather data.

"We found that ASR provides new vision of the cyclone activity in high latitudes, showing that the Arctic is much more densely populated with cyclones than was suggested by the global re-analyses," Tilinina said.

One global data set used for comparison was ERA-Interim, which is generated by the European Centre for Medium-Range Weather Forecasts. Focusing on ERA-Interim data for latitudes north of 55 degrees, Tilinina and Gulev identified more than 1,200 cyclones per year between 2000 and 2010. For the same time period, ASR data yielded more than 1,900 cyclones per year.

When they narrowed their search to cyclones that occurred directly over the Arctic Ocean, they found more than 200 per year in ERA-Interim, and a little over 300 per year in ASR.

There was good agreement between all the data sets when it came to big cyclones, the researchers found, but the Arctic-centered ASR appeared to catch smaller, shorter-lived cyclones that escaped detection in the larger, global data sets. The ASR data also provided more detail on the biggest cyclones, capturing the very beginning of the storms earlier and tracking their decay longer.

Extreme Arctic cyclones are of special concern to climate scientists because they melt sea ice, Bromwich said.

"When a cyclone goes over water, it mixes the water up. In the tropical latitudes, surface water is warm, and hurricanes churn cold water from the deep up to the surface. In the Arctic, it's the exact opposite: there's warmer water below, and the cyclone churns that warm water up to the surface, so the ice melts."

As an example, he cited the especially large cyclone that hit the Arctic in August 2012, which scientists believe played a significant role in the record retreat of sea ice that year.


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New phone alerts for extreme weather may prevent casualties in India

When Cyclone Phailin hit India in late 2013 it became the largest storm to batter the subcontinent in over a decade. The storm, officially classified as a Category 5 tropical cyclone, affected more than 12 million people in India and neighboring countries, and required mass evacuations.

These evacuations revealed an urgent need for an effective alert system which could forewarn the majority of the population. A new paper published in Atmospheric Science Letters details how computer science undergraduates have created image based mobile phone alerts, connected to the Weather Research and Forecasting system.

India has a mobile phone subscriber base exceeding 929 million people and this is expected to touch 1.15 billion by the end of 2014. An alert system developed for mobiles could reach an estimated 97% of the population..

The paper details how during the 2013 storm the computer scientists were able to track its genesis, progression and landfall. By converting this information into images suitable for phones, they created a forecasting and warning system accessible to ordinary citizens.

"Cyclone alerts can save lives and property, but must be easily accessible," said Dr. Sat Ghosh. "The global perception of India's emerging IT prowess is lopsided. It is thought of as merely a manufacturing hub; however, our article puts the country's numerical literacy to practical use. The easy-to-use Weather Research and Forecasting model remains confined to an elite group of users, such as atmospheric scientists and weather forecasters. Our research explores how the WRF forecast can be interfaced with mobile telephony which has a deep penetration even in rural pockets of India."

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Solar activity not a key cause of climate change, study shows

Climate change has not been strongly influenced by variations in heat from the sun, a new scientific study shows.

The findings overturn a widely held scientific view that lengthy periods of warm and cold weather in the past might have been caused by periodic fluctuations in solar activity.

Research examining the causes of climate change in the northern hemisphere over the past 1000 years has shown that until the year 1800, the key driver of periodic changes in climate was volcanic eruptions. These tend to prevent sunlight reaching Earth, causing cool, drier weather. Since 1900, greenhouse gases have been the primary cause of climate change.

The findings show that periods of low sun activity should not be expected to have a large impact on temperatures on Earth, and are expected to improve scientists' understanding and help climate forecasting.

Scientists at the University of Edinburgh carried out the study using records of past temperatures constructed with data from tree rings and other historical sources. They compared this data record with computer-based models of past climate, featuring both significant and minor changes in the sun.

They found that their model of weak changes in the sun gave the best correlation with temperature records, indicating that solar activity has had a minimal impact on temperature in the past millennium.

The study, published in Nature GeoScience, was supported by the Natural Environment Research Council.

Dr Andrew Schurer, of the University of Edinburgh's School of GeoSciences, said: "Until now, the influence of the sun on past climate has been poorly understood. We hope that our new discoveries will help improve our understanding of how temperatures have changed over the past few centuries, and improve predictions for how they might develop in future. Links between the sun and anomalously cold winters in the UK are still being explored."


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Climatological software developed for massive use

Understanding the weather behavior may not be as complicated as once thought, and would help to have more elements for decision making and prevention of natural disasters, as hurricanes or typhoons.

Researchers from the National Autonomous University of Mexico (UNAM) make available for anyone the opportunity to know their community, state or country's weather activity for today and months ahead.

A group of specialists from the Center of Environmental Geography Research (CIGA) designed the software Moclic (Monitoring Climate Change) trough which is possible to organize, store and operate geo-referenced data from climate elements.

Francisco Bautista Z??iga, researcher at CIGA and head of Monoclic project, points out that the software allows an agronomist to obtain annual rainfall records and relate them to the crops production figures for explanation of a possible event.

"Likewise, is possible to identify desiccation processes in a region, which comes useful when considering the use of improved seeds that can resist droughts, or the optimization of rainwater catching techniques, storage or types of irrigation.

"A physician can obtain information about the climatic tendencies of specific periods of time to know the behavior of intestinal diseases in certain weather conditions," explains Bautista Z??iga.

He points out that knowing the tendencies regarding the change of atmospheric conditions is needed by every federal entity, since it can help taking measures prior to a possible flood.

Moclic can calculate bio and agroclimatic indicators, such as humidity, aridity, rain erosion and rainfall concentration.

The software was designed for Windows, looking to favor practicality for the user. It feeds on data from weather stations in any state or country, unlike current software that use global information, with which what happens in a small ranch regarding temperature can be known more accurately and foresee the maximum, minimum and average records.

"The use of Moclic with local data is of great importance because global models don't include land relief nor closeness to sea data, among others. The software is very simple and can be used by decision making characters, as governors, breeders, physicians, farmers, students, or anyone whose repercussions could have economic, politic or social effects."

Moclic was design by specialist at the CIGA with the participation of professors from the Superior Technological Institute of Tac?mbaro, Michoac?n. For its commercialization, Bautista Z??iga is creating an enterprise with global reach, since the software has been requested in the United States of America, Europe and Brazil.


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Picture of how our climate is affected by greenhouse gases is a 'cloudy' one

The warming effect of human-induced greenhouse gases is a given, but to what extent can we predict its future influence? That is an issue on which science is making progress, but the answers are still far from exact, say researchers from the Hebrew University of Jerusalem, the US and Australia who have studied the issue and whose work which has just appeared in the journal Science.

Indeed, one could say that the picture is a "cloudy" one, since the determination of the greenhouse gas effect involves multifaceted interactions with cloud cover.

To some extent, aerosols -- particles that float in the air caused by dust or pollution, including greenhouse gases -- counteract part of the harming effects of climate warming by increasing the amount of sunlight reflected from clouds back into space. However, the ways in which these aerosols affect climate through their interaction with clouds are complex and incompletely captured by climate models, say the researchers. As a result, the radiative forcing (that is, the disturbance to Earth's "energy budget" from the sun) caused by human activities is highly uncertain, making it difficult to predict the extent of global warming.

And while advances have led to a more detailed understanding of aerosol-cloud interactions and their effects on climate, further progress is hampered by limited observational capabilities and coarse climate models, says Prof. Daniel Rosenfeld of the Fredy and Nadine Herrmann Institute of Earth Sciences at the Hebrew University of Jerusalem, author of the article in Science. Rosenfeld wrote this article in cooperation with Dr. Steven Sherwood of the University of New South Wales, Sydney, Dr. Robert Wood of the University of Washington, Seattle, and Dr. Leo Donner of the US National Oceanic and Atmospheric Administration. .

Their recent studies have revealed a much more complicated picture of aerosol-cloud interactions than considered previously. Depending on the meteorological circumstances, aerosols can have dramatic effects of either increasing or decreasing the cloud sun-deflecting effect, the researchers say. Furthermore, little is known about the unperturbed aerosol level that existed in the preindustrial era. This reference level is very important for estimating the radiative forcing from aerosols.

Also needing further clarification is the response of the cloud cover and organization to the loss of water by rainfall. Understanding of the formation of ice and its interactions with liquid droplets is even more limited, mainly due to poor ability to measure the ice-nucleating activity of aerosols and the subsequent ice-forming processes in clouds.

Explicit computer simulations of these processes even at the scale of a whole cloud or multi-cloud system, let alone that of the planet, require hundreds of hours on the most powerful computers available. Therefore, a sufficiently accurate simulation of these processes at a global scale is still impractical.

Recently, however, researchers have been able to create groundbreaking simulations in which models were formulated presenting simplified schemes of cloud-aerosol interactions, This approach offers the potential for model runs that resolve clouds on a global scale for time scales up to several years, but climate simulations on a scale of a century are still not feasible. The model is also too coarse to resolve many of the fundamental aerosol-cloud processes at the scales on which they actually occur. Improved observational tests are essential for validating the results of simulations and ensuring that modeling developments are on the right track, say the researchers.

While it is unfortunate that further progress on understanding aerosol-cloud interactions and their effects on climate is limited by inadequate observational tools and models, achieving the required improvement in observations and simulations is within technological reach, the researchers emphasize, provided that the financial resources are invested. The level of effort, they say, should match the socioeconomic importance of what the results could provide: lower uncertainty in measuring human-made climate forcing and better understanding and predictions of future impacts of aerosols on our weather and climate.


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Raindrop research dials in satellite forecasting accuracy

Dialing in the accuracy of satellite weather forecasting is the goal behind basic research into raindrop size and shape being done at The University of Alabama in Huntsville by a UAH doctoral student who is also an atmospheric scientist in the NASA Pathways Intern Employment Program.

Patrick Gatlin says his work measuring the height and width of raindrops using ground instruments provides an accuracy baseline that is then scaled up to ground radar and then to satellite measurements. He is co-author of a paper on the topic.

"That's really the whole purpose of measuring raindrops, is for remote sensing purposes," Gatlin says. Scaling up accuracy from a small sensor on the ground to large sections of the Earth being observed from space requires very accurately calibrated instruments. "Our ability to correctly depict rainfall using a sensor in space is closely tied to knowing how precipitation varies, right down to the individual raindrop and snowflake size."

Perfecting ground-level instrument observations, enlarging those to encompass ground-based radar and then going even larger to develop accurate satellite measuring instruments is the best way to reduce error as the area under observation increases. "Before we invest in all this satellite instrumentation," Gatlin says, "let's make sure we've got it right."

A coming big step in scaling up precipitation forecasting is NASA's planned launch of its Global Precipitation Measurement (GPM) satellite toward the end of February. UAH is a mission contractor, headed at the university by Dr. Larry Carey, an associate professor of atmospheric science, and involving UAH Earth System Science Center research scientist Matt Wingo, who is working with NASA at their flight facility in Wallops Island, Va.

"UAH designed the platform for some of the ground-based instruments that will validate the information from the satellite," says Gatlin.

Carrying an advanced radar/radiometer system to measure precipitation from space, the GPM is the core of what will be a global network of measuring satellites that will provide next-generation global observations of rain and snow. It will serve as a reference standard to unify precipitation measurements from a constellation of research and operational satellites.

Through improved measurements of precipitation globally, the GPM mission will help to advance understanding of Earth's water and energy cycle, improve forecasting of extreme events that cause natural hazards and disasters, and extend current capabilities in using accurate and timely precipitation information.

In his own research, Gatlin has ranged from Iowa and Oklahoma to Canada, Finland, Italy and France. Rather than raindrops, the Canadian research was designed to collect snowflake images in order to improve the accuracy of measuring devices for snowfall.

In each locale, an integrated network of ground-level measuring devices have been deployed, like the Parsivel2, a disdrometer that measures the particle size and velocity of raindrops falling through a laser. Also in use are two-dimensional video disdrometers, which use two video angles to create 2-D pictures that enable determination of raindrop shapes. A video disdrometer on loan from frequent research collaborator Colorado State University is located on the UAH campus behind Cramer Hall.

During a field study, the instruments on the ground take measurements while a plane flies through the clouds to collect actual raindrop information and another flies high above the clouds with remote sensing equipment to mimic satellite radar detection. Results from all the measurement methods are compared.

Enhanced satellite-based precipitation measurements will improve both rainfall and snowfall predictions on a global scale, Gatlin says. "We'll be measuring rain and snow in some areas where we've never measured it before." The ability to better measure raindrop size also can have impact on severe weather forecasting, as small raindrops lead to higher evaporation rates that have been correlated with larger and more forceful microbursts by UAH's Dr. Kevin Knupp and others.

Gatlin is about to finish up a global study focusing just on very large raindrops 5 millimeters in size and larger. These drops are difficult to capture in the small measuring area afforded by measuring instruments, and so their observation is rare. Gatlin says out of 224 million drops he has researched, only 8,000 have been 5 mm or larger.

"Even though large raindrops can have the greatest impact on radar measurements, we don't have a good idea of their concentration," he says. "What I've been doing is bringing together all the raindrop data bases that have collected various types of rainfall data using the same techniques."

Interestingly, while Sumatra holds the honor of having the greatest number of large drops overall, the largest drop collected in his study fell through a measuring device at the UAH campus. It measured 9.1 mm and was formed in a hailstorm when a falling piece of hail melted before landing.


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Get used to heat waves: Extreme El Nino events to double

Extreme weather events fueled by unusually strong El Ninos, such as the 1983 heatwave that led to the Ash Wednesday bushfires in Australia, are likely to double in number as our planet warms.

An international team of scientists from organizations including the ARC Centre of Excellence for Climate System Science (CoECSS), the US National Oceanic and Atmospheric Administration and CSIRO, published their findings in the journal Nature Climate Change.

"We currently experience an unusually strong El Ni?o event every 20 years. Our research shows this will double to one event every 10 years," said co-author, Dr Agus Santoso of CoECSS.

"El Nino events are a multi-dimensional problem, and only now are we starting to understand better how they respond to global warming," said Dr Santoso. Extreme El Ni?o events develop differently from standard El Ninos, which first appear in the western Pacific. Extreme El Nino's occur when sea surface temperatures exceeding 28?C develop in the normally cold and dry eastern equatorial Pacific Ocean. This different location for the origin of the temperature

increase causes massive changes in global rainfall patterns.

"The question of how global warming will change the frequency of extreme El Ni?o events has challenged scientists for more than 20 years," said co-author Dr Mike McPhaden of US National Oceanic and Atmospheric Administration.

"This research is the first comprehensive examination of the issue to produce robust and convincing results," said Dr McPhaden.

The impacts of extreme El Ni?o events extend to every continent across the globe.

The 1997-98 event alone caused $35-45 US billion in damage and claimed an estimated 23,000 human lives worldwide.

"During an extreme El Ni?o event countries in the western Pacific, such as Australia and Indonesia, experienced devastating droughts and wild fires, while catastrophic floods occurred in the eastern equatorial region of Ecuador and northern Peru," said lead author, CSIRO's Dr Wenju Cai

In Australia, the drought and dry conditions induced by the 1982-83 extreme El Ni?o preconditioned the Ash Wednesday Bushfire in southeast Australia, leading to 75 fatalities.

To achieve their results, the team examined 20 climate models that consistently simulate major rainfall reorganization during extreme El Ni?o events. They found a substantial increase in events from the present-day through the next 100 years as the eastern Pacific Ocean warmed in response to global warming.

"This latest research based on rainfall patterns, suggests that extreme El Ni?o events are likely to double in frequency as the world warms leading to direct impacts on extreme weather events worldwide."

"For Australia, this could mean summer heat waves, like that recently experienced in the south-east of the country, could get an additional boost if they coincide with extreme El Ninos," said co-author, Professor Matthew England from CoECSS.


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