Atmospheric

There's no dispute that natural variations of atmospheric air flow patterns have played an important role in climate change in the last decades. Basic knowledge of how and why it happens is necessary to improve climate models that still hold much uncertainty. Researchers investigating a fundamental climate process in the Arctic state that interactions between the stratospheric ozone chemistry and atmospheric air flow lead to significant changes of airflow patterns from the ground up to the stratosphere. Atmospheric airflows follow preferred patterns. The most important pattern for the…

Scientists have solved a 40-year-old puzzle by identifying the origin of the intense radio waves in the Earth's upper atmosphere that control the dynamics of the Van Allen radiation belts — belts consisting of high-energy electrons that can damage satellites and spacecraft and pose a risk to astronauts performing activities outside their spacecraft. The source of these low-frequency radio waves, which are known as plasmaspheric hiss, turns out to be not lightning or instabilities from a plasma, as previously proposed, but an intense electromagnetic wave type called "chorus," which energizes…

A destructive spring freeze that chilled the eastern United States almost a year ago illustrates the threat a warming climate poses to plants and crops, according to a paper just published in the journal BioScience. The study was led by a team from the Department of Energy's Oak Ridge National Laboratory. The "Easter freeze" of April 5-9, 2007, blew in on an ill wind. Plants had been sending out young and tender sprouts two to three weeks earlier than normal during an unusually warm March. Plant ecologists, as well as farmers and gardeners, took note of the particularly harsh turn of the…

Modern diesel cars are quieter than their predecessors but also release considerably fewer exhaust fumes into the atmosphere. But the real culprit in diesel are heavy-duty, construction and off-road vehicles - they're often special vehicles made in small batches and each requires a different filter geometry. The filters for are not yet state-of-the-art. A new diesel particulate filter technology will soon teach even these vehicles to give up smoking. Conventional diesel soot filters usually consist of cylindrical ceramic blocks crisscrossed by numerous channels. A block of this kind cannot…

Research from ancient sediment cores indicates that a warming climate could make the world’s arctic tundra far more susceptible to fires than previously thought. The findings are important given the potential for tundra fires to release organic carbon – which could add significantly to the amount of greenhouse gases already blamed for global warming. Montana State University post-doctoral researcher Philip Higuera is the lead author on the paper, which summarizes a portion of a four-year study funded by the National Science Foundation. Higuera and his co-authors examined ancient sediments…

Widespread damage to plants from a sudden freeze that occurred across the Eastern United States from 5 April to 9 April 2007 was made worse because it had been preceded by two weeks of unusual warmth, according to an analysis published in BioScience. The authors of the report, Lianhong Gu and his colleagues at the Oak Ridge National Laboratory and collaborators at NASA, the University of Missouri, and the National Oceanic and Atmospheric Administration, found that the freeze killed new leaves, shoots, flowers, and fruit of natural vegetation, caused crown dieback of trees, and led to severe…

Brent Christner, LSU professor of biological sciences, in partnership with colleagues in Montana and France, recently found evidence that rain-making bacteria are widely distributed in the atmosphere. These biological particles could factor heavily into the precipitation cycle, affecting climate, agricultural productivity and even global warming. Christner’s team examined precipitation from global locations and demonstrated that the most active ice nuclei – a substrate that enhances the formation of ice – are biological in origin. This is important because the formation of ice in clouds is…

Researchers writing in PMC Physics B have found that the rate at which electrons lose energy to carbon monoxide is greater than that to carbon dioxide at higher levels in the atmospheres of both Mars and Venus. This finding contributes to the body of knowledge required for modelling of the atmospheres of Mars and Venus, which in turn provides an opportunity to validate the techniques used in modelling of more complicated atmospheres such as that of Earth. Solar energy is both absorbed in atmospheres and eventually emitted to space by processes at the atomic level. These complicated processes…

A discovery in molecular chemistry may help remove a barrier to widespread use of diesel and other fuel-efficient "lean burn" vehicle engines. Researchers at the Department of Energy's Pacific Northwest National Laboratory have recorded the first observations of how certain catalyst materials used in emission control devices are constructed. The PNNL team observed how barium oxide attaches itself to the surface of gamma-alumina. Barium oxide is a compound that absorbs toxic nitrogen oxide, commonly referred to as NOx, from tail-pipe emissions. Gamma alumina is a form of aluminum oxide that…

Research carried out by scientists from Earthwatch, the international environmental charity, has reinforced the urgent need to protect Europe’s remaining peat bogs. Dubbed the ‘rainforests of Europe’ as they are so diverse in wildlife, peat bogs contain more than 20 per cent of the world’s carbon. However, western Europe has lost most of its natural peat bogs, largely due to peat extraction for horticulture. Over the last three years, Earthwatch scientists have conducted the first botanical survey of Yelyna, the largest raised peat bog in Europe and a Ramsar Wetland of International…