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Snowy Owls lead nomadic lives and travel vast distances from year to year searching for productive feeding areas. Some years, most recently in the winter of 2011/2012, conditions cause them to come south in great numbers. Get an intimate look at these white owls from the north through video and photographs captured by the Cornell Lab of Ornitholgy's Gerrit Vyn.
The Sea Shepherd Conservation Society
Three anti-whaling protesters were injured when activists from the Sea Shepherd organisation clashed with a Japanese whaling vessel about 300 miles north of Mawson Peninsula off the George V Land coast of Antarctica.
The Japanese whalers have escalated their aggression by throwing iron grappling hooks at Sea Shepherd boats. Two Steve Irwin crew were struck in the shoulder with iron grappling hooks and one crewmember was struck twice in the face with a long bamboo pole.
American crewmember Brian Race, (25) from New York, was jabbed twice in the face with a bamboo pole receiving lacerations above his right eye and on his nose. Russell Bergh of South Africa, (35) a cameraman for Animal Planet, was struck in the right arm and shoulder with an iron grappling hook thrown from the harpoon vessel resulting in deep bruising. Photographer Guillaume Collet of France, (27) was also struck in the right arm and shoulder by an iron grappling hook resulting in deep bruising. There were no injuries incurred by any of the crew on the Japanese vessel.
The map shows the temporal trend of bird and butterfly CTI for each country.
Åke Lindström is Professor of Animal Ecology at Lund University, Sweden. Together with other European researchers he has looked at 20 years' worth of data on birds, butterflies and summer temperatures. During this period, Europe has become warmer and set temperatures have shifted northwards by 250 km. Bird and butterfly communities have not moved at the same rate.
"Both butterflies and birds respond to climate change, but not fast enough to keep up with an increasingly warm climate. We don't know what the long-term ecological effects of this will be", says Åke Lindström.
Butterflies have adapted more quickly to the changing temperatures and have moved on average 114 km north, whereas birds have only moved 37 km. A likely reason is that butterflies have much shorter lifespans and therefore adapt more quickly to climate change. Because birds like to return to the same breeding ground as in previous years, there is also greater inertia in the bird system.
"A worrying aspect of this is if birds fall out of step with butterflies, because caterpillars and insects in general represent an important source of food for many birds", says Åke Lindström.
Sweden shows the strongest trends with regard to birds; however, there is no corresponding Swedish data for butterflies. For the study, the birds have been divided into 'cold' and 'warm' species, i.e. birds that thrive in slightly cooler or warmer temperatures. For example, chaffinches and reed buntings are 'colder' species and blackcaps and goldfinches 'warmer' species. In general, the researchers have observed that 'warm' birds are on the increase and 'cold' birds are in decline. When new species are seen in an area and others disappear, it is more often 'warm' species that arrive and 'cold' species that disappear.
"Over the past 50 years the main factors affecting bird and butterfly numbers and distribution have been agriculture, forestry and urbanisation. Climate change is now emerging as an increasingly important factor in the development of biodiversity", says Åke Lindström, continuing: "For Sweden, this will probably mean more species of bird in the long run; many new species are already arriving from the continent."
Åke Lindström works among other things on the projects BECC (Biodiversity and Ecosystem Services in a Changing Climate) and CanMove (Centre for Animal Movement Research) at Lund University in Sweden.
The study is a joint European project with data from 20 years and seven countries (Spain, France, the Netherlands, Sweden, the UK, Finland and the Czech Republic). The Swedish data covers birds and temperatures and has been gathered on behalf of the Swedish Environmental Protection Agency.
Contact: Åke Lindström
Ake.Lindstrom@biol.lu.se
46-706-975-931
Lund University
By looking at the stability of the atmosphere, wind farm operators could gain greater insight into the amount of power generated at any given time.
Power generated by a wind turbine largely depends on the wind speed. In a wind farm in which the turbines experience the same wind speeds but different shapes (such as turbulence) to the wind profile, a turbine will produce different amounts of power.
And this variable power can be predicted by looking at atmospheric stability, according to Lawrence Livermore National Laboratory scientist Sonia Wharton and colleague Julie Lundquist of the University of Colorado at Boulder and the National Renewable Energy Laboratory.
In a paper appearing in the Jan. 12 edition of the journal, Environmental Research Letters, Wharton and Lundquist examined turbine-generated power data, segregated by atmospheric stability, to figure out the power performance at a West Coast wind farm.
"The dependence of power on stability is clear, regardless of whether time periods are segregated by three-dimensional turbulence, turbulence intensity or wind shear," Wharton said.
The team found that power generated at a set wind speed is higher under stable conditions and lower under strongly unsteady conditions at that location. The average wind power output difference is as high as 15 percent less wind power generation when the atmosphere is unstable.
While turbulence is a relatively well-known term in assessing turbine efficiency, wind shear -- which is a difference in wind speed and direction over a relatively short distance in the atmosphere -- also plays an important role when assessing how much power a turbine generates over certain time scales.
Wharton and Lundquist said that wind farm operators could better estimate how much power is generated if the wind forecasts included atmospheric stability impact measurements.
Though earlier research looked at atmospheric stability effects on power output, few studies have analyzed power output from modern turbines with hub heights of more than 60 meters.
In the new research, Wharton and Lundquist gathered a year of power data from upwind modern turbines (80 meters high) at a multi-megawatt wind farm on the West Coast. They considered turbine power information as well as meteorological data from an 80-meter tall tower and a Sonic Detection and Ranging (SODAR), which provided wind profiles up to 200 meters above the surface, to look at turbulence and wind shear. Looking at upwind turbines removed any influence that turbine wakes may have on power performance.
The team found that wind speed and power production varied by season as well as from night to day. Wind speeds were higher at night (more power) than during the day (less power) and higher during the warm season (more power) than in the cool season (less power). For example, average power production was 43 percent of maximum generation capacity on summer days and peaked at 67 percent on summer nights.
"We found that wind turbines experienced stable, near-neutral and unstable conditions during the spring and summer," Wharton said. "But daytime hours were almost always unstable or neutral while nights were strongly stable."
"This work highlights the benefit of observing complete profiles of wind speed and turbulence across the turbine rotor disk, often available only with remote sensing technology like SODAR or LIDAR (Laser Detection and Ranging,)" Lundquist said. "Wind energy resource assessment and power forecasting would profit from this increased accuracy."
Founded in 1952, Lawrence Livermore National Laboratory provides solutions to our nation's most important national security challenges through innovative science, engineering and technology. Lawrence Livermore National Laboratory is managed by Lawrence Livermore National Security, LLC for the U.S. Department of Energy's National Nuclear Security Administration.
Contact: Anne Stark
stark8@llnl.gov
925-422-9799
DOE/Lawrence Livermore National Laboratory
