Photo‐chemically released land snow‐based Bromine affect O3 depletion at Poles The chemical element bromine, whose compounds contribute significantly to the depletion of ozone in the lower atmosphere, is also released in Polar regions to a great extent from snow on land. Until now, scientists has assumed that sea ice was the sole source of bromine emissions. A novel spectroscopic measurement device, developed in Heidelberg, was used aboard an American research aircraft for this study carried out in Alaska by an international research team of scientists from the Institute of Environmental Physics of Heidelberg University and colleagues from the USA. Ozone plays a key role not only in the stratosphere, but also on the ground, where it is useful for the self‐cleaning of the atmosphere and removal of contaminants. In the 1990s Heidelberg researchers had already discovered that the extensive ozone depletion in the atmosphere close to the ground in the Arctic and Antarctic was due to a reaction of bromine with ozone, producing bromine oxide. This bromine is released in autocatalytic processes. During the polar spring, the resulting bromine oxide clouds can spread over several thousand square kilometres. The present investigations in Alaska have yielded a new information on the release of bromine from ice and snow. The researchers studied a variety of samples taken on site and inferred that the bromine‐release processes are correlated to daylight, and thus involve photochemical reactions. Most importantly, however, the team was able to prove that the bromine emissions depended heavily on the pH value of the snow or ice sample. "The more acidic the sample, the more bromine was released. This led to the surprising result that snow on land, which is typically acidic, releases more bromine than alkaline sea ice, even though sea ice clearly contains more bromine. The scientists from Heidelberg University confirmed these findings particularly through simultaneous observations from the aircraft. The instrument measures the sunlight reflected and scattered on the surface of the snow and in the atmosphere. Bromine oxide absorbs some of the sunlight. Based on the amount of absorption, the Heidelberg scientists were able to determine the bromine concentration and its vertical distribution up to several kilometres altitude. They also obtained data on its horizontal distribution. The studies were conducted as part of the Bromine, Ozone and Mercury Experiment (BROMEX). Journal Reference:
K. A. Pratt, K. D. Custard, P. B. Shepson, T. A. Douglas, D. Pöhler, S. General, J. Zielcke, W. R. Simpson, U. Platt, D. J. Tanner, L. G. Huey, M. Carlsen, B. H. Stirm. Photochemical production of molecular bromine in Arctic surface snowpacks. Nature Geoscience, 2013; DOI: 10.1038/ngeo1779. New Evidence Indicates Auroras occur Outside Our Solar System University of Leicester planetary scientists have found new evidence that Auroras occur on several planets within our solar system, and the brightest ‐ on Jupiter – are 100 times brighter than those on Earth. However, no auroras have yet been observed beyond Neptune. A new study has shown that processes strikingly similar to those which power Jupiter’s auroras could be responsible for radio emissions detected from a number of objects outside our solar system. In addition, the radio emissions are powerful enough to be detectable across interstellar distances – meaning that auroras could provide an effective way of observing new objects outside our solar system. Auroras occur when charged particles in an object’s magnetosphere collide with atoms in its upper atmosphere, causing them to glow. However, before hitting the atmosphere, these particles also emit radio waves into space. The study which recently appeared in the Astrophysical Journal, shows that this phenomenon is not limited to our solar system. It shows that the radio emissions from a number of ultracool dwarfs may be caused in a very similar, but significantly more powerful, way to Jupiter’s auroras. Dr Nichols from the University of Leicester’s Department of Physics and Astronomy has recently shown that beefed‐up versions of the auroral processes on Jupiter are able to account for the radio emissions observed from certain "ultracool dwarfs" ‐ bodies which comprise the very lowest mass stars ‐ and "brown dwarfs" ‐ 'failed stars' which lie in between planets and stars in terms of mass. The paper could have major implications for the detection of planets and objects outside our solar system which could not be discovered with other methods. What’s more, the radio emission could provide us with key information about the length of the planet’s day, the strength of its magnetic field, how the planet interacts with its parent star and even whether it has any moons. Journal Reference: J. D. Nichols, M. R. Burleigh, S. L. Casewell, S. W. H. Cowley, G. A. Wynn, J. T. Clarke, A. A. West. Origin of Electron Cyclotron Maser Induced Radio Emissions at Ultracool Dwarfs: Magnetosphere‐Ionosphere Coupling Currents. The Astrophysical Journal, 2012; 760 (1): 59 DOI: 10.1088/0004‐
637X/760/1/59.