Solar irradiance, cosmic rays and cloudiness over daily timescales

Latest publications

Written by Jaša Čalogović Tuesday, 20 December 2011 00:00

thumb cloudsAlthough over centennial and greater timescales solar variability may be one of the most influential climate forcing agents, the extent to which solar activity influences climate over shorter time periods is poorly understood. If a link exists between solar activity and climate, it is likely via a mechanism connected to one (or a combination) of the following parameters: total solar irradiance (TSI), ultraviolet (UV) spectral irradiance, or the galactic cosmic ray (GCR) flux. We present an analysis based around a superposed epoch (composite) approach focusing on the largest TSI increases and decreases (the latter occurring in both the presence and absence of appreciable GCR reductions) over daily timescales...

 GRL website

 

Cosmic ray modulation by different types of solar wind disturbances

Latest publications

Written by Mateja Dumbovic Tuesday, 20 December 2011 00:00

SWD-CR-dumbovic-2011The amount of the galactic cosmic rays (primarily protons) that hit the Earth is greatly influenced by the solar activity. On the short time scales it can be substantially reduced by the passing of solar wind disturbances, such as interplanetary coronal mass ejections (ICMEs) and corotating interaction regions (CIRs). The resulting short-term cosmic ray depressions are generally denoted as Forbush decreases. We present a systematic statistical study of various aspects of Forbush decreases. The analysis is based on ground-based neutron monitor data and the in-situ solar wind data recorded by the Advanced Composition Explorer (ACE) satellite and provides empirical background for physical interpretations of short-term cosmic ray modulations.


 read publication (A&A website)
 

First announcement - XIth Hvar Astrophysical Colloquium

Latest news

Tuesday, 01 November 2011 03:12

binary starAt the occasion of the 40th anniversary of Hvar Observatory, XIth Hvar Astrophysical Colloquium: The Most Mysterious Binaries: Significance for Astrophysics will be organized from 2. to 6. July 2012  in Town Loggia, Hvar, Croatia. The scientific sessions will include topics:  Binaries as Tests of Stellar Evolution Models, Extreme and Unusual Binaries, Rapid Phases of Binary Evolution, Be Binaries and Highest to Lowest Mass Binaries. Deadline for a regular registration is 15. March 2012 (150 EUR) where after this deadline the late registration will be charged with 200 EUR.


 first announcement
 further details & registration 

 

First announcement - XIIth Hvar Astrophysical Colloquium

Latest news

Tuesday, 01 November 2011 03:12

thumb sun_heliosphereAt the occasion of the 40th anniversary of Hvar Observatory, XIIth Hvar Astrophysical Colloquium: The Sun and Heliosphere will be organized from 3. to 7. September 2012  in Town Loggia, Hvar, Croatia. The scientific sessions will include following topics: The Solar Photosphere - Theory and Observations, The Chromosphere - Link between the Photosphere and Corona, Eruptive Processes, CME's and Energetic Particles, Solar-terrestrial Connection and the Heliosphere, Observing Techniques, Data Analysis and Archives.
 
 pdffirst announcement
 further details & registration 
 

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  • Solar Activity Level: LOW
    Solar Activitly level is LOW.

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  • Most Active Region: NOAA 12529
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