* Astronomy

University of Hertfordshire astronomers have made an unexpected find using a polarimeter (an instrument used to measure the wave properties of light) funded by the Science and Technology Facilities Council (STFC), that has the potential to affect future climate models.
The astronomers were making observations of the stars in search of new planets after mounting the 'PlanetPol' (polarimeter they designed and constructed to take extremely sensitive readings) on the William Herschel Telescope (part of the Isaac Newton Group of Telescopes) in La Palma in the Canary Islands, when their measurements became affected by a layer of dust.
The presence of the dust itself, which satellite images and modelling of the dust's movement show had originated from the Sahara and the Sahel, was not a surprise, but its behaviour was. Scientists normally assume that aerosols, including mineral dust, have random orientation in the atmosphere, but the team members say the polarising affect the dust was having on the light could only be the result of dust particles being vertically aligned.

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Antarctica, the only place that had oddly seemed immune from climate change, is warming after all, according to a new study. For years, Antarctica was an enigma to scientists who track the effects of global warming. Temperatures on much of the continent at the bottom of the world were staying the same or slightly cooling, previous research indicated.

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British climate scientists said on Tuesday that the coming year is likely to be one of the top-five warmest on record. Despite the continued cooling of huge areas of the Pacific Ocean a phenomenon known as La Ninathe average global temperature for 2009 is expected to be more than 0.4 degrees Celsius above the long-term average. According to researchers at the Met Office, that would make it the warmest year since 2005, as there is also a growing probability of record temperatures after next year.

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Title: Cosmic rays, cloud condensation nuclei and clouds - a reassessment using MODIS data
Authors: J. E. Kristjánsson, C. W. Stjern, F. Stordal, A. M. Fjæraa, G. Myhre, and K. Jónasson

The response of clouds to sudden decreases in the flux of galactic cosmic rays (GCR) - Forbush decrease events - has been investigated using cloud products from the space-borne MODIS instrument, which has been in operation since 2000. By focusing on pristine Southern Hemisphere ocean regions we examine areas where we believe that a cosmic ray signal should be easier to detect than elsewhere. While previous studies have mainly considered cloud cover, the high spatial and spectral resolution of MODIS allows for a more thorough study of microphysical parameters such as cloud droplet size, cloud water content and cloud optical depth, in addition to cloud cover. Averaging the results from the 22 Forbush decrease events that were considered, no statistically significant correlations were found between any of the four cloud parameters and GCR, when autocorrelations were taken into account. Splitting the area of study into six domains, all of them have a negative correlation between GCR and cloud droplet size, in agreement with a cosmic ray - cloud coupling, but in only one of the domains (eastern Atlantic Ocean) was the correlation statistically significant. Conversely, cloud optical depth is mostly negatively correlated with GCR, and in the eastern Atlantic Ocean domain that correlation is statistically significant. For cloud cover and liquid water path, the correlations with GCR are weaker, with large variations between the different domains. When only the six Forbush decrease events with the largest amplitude (more than 10% decrease) were studied, the correlations fit the hypothesis slightly better, with 16 out of 24 correlations having the expected sign, although many of the correlations are quite weak. Introducing a time lag of a few days for clouds to respond to the cosmic ray signal the correlations tend to become weaker and even to change sign.

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A new study supports earlier findings by stating that changes in cosmic rays most likely do not contribute to climate change. It is sometimes claimed that changes in radiation from space, so-called galactic cosmic rays, can be one of the causes of global warming. A new study, investigating the effect of cosmic rays on clouds, concludes that the likelihood of this is very small.
A group of researchers from the University of Oslo, Norwegian Institute for Air Research (NILU), CICERO Center for Climate and Environmental Research, and the University of Iceland, are behind the study.

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