Forbush decreases – clouds relation in the neutron monitor era
31 Aug 2011
1Institute of Physics, University of Belgrade, Pregrevica 118, Belgrade, Serbia
2Faculty of Physics, University of Belgrade, Studentski trg 16, Belgrade, Serbia
Received: 15 November 2010 – Revised: 15 February 2011 – Accepted: 23 March 2011 – Published: 31 August 2011Abstract. The proposed influence of cosmic rays on cloud formation is tested for the effect of sudden intensity changes of CR (Forbush decreases) on cloudiness. An attempt is made to widen the investigated period covered by satellite observation of cloudiness. As an indicator of cloud cover, the diurnal temperature range (DTR - a quantity anticorrelated with cloudiness) is used. The superposed epoch analysis on a set of isolated Forbush decreases is conducted and the results for a region of Europe are presented. The effect of Forbush decrease on DTR is statistically significant only if the analysis is restricted to high amplitude FDs (above the threshold value of 7% with the respect to undisturbed CR intensity). The magnitude of the effect on DTR is estimated to be (0.38 ± 0.06) °C.