WP2: Influence of solar variability on Earth's climate

The research within WP2 considers investigation of the impact of the solar-modulated energetic particles flux on the Earth's atmosphere, the development of rigorous statistical examination methods based on the Monte Carlo approach, the influence of energetic particles within the global electric-current circuit on hypothesized changes in cloud microphysics and lightning phenomenon, and analysis of long-term ground-based measurements, to extend the potential analysis period to pre-satellite era. The research in the frame of WP2 is based on the analysis of numerous satellite and ground-based datasets. Results will be compared with theoretical mechanisms and models to test their relevance for the solar-terrestrial connection.


T2.1. Data compiling and development of statistical methods for the data analysis

In Task 2.1 the cosmic ray (CR) flux data archives are compiled to obtain a catalogue of all short-term events with largest deviations in CR flux (Forbush decreases, FDs and Ground Level Enhancements, GLEs). In addition, the diurnal temperatures (DTR) data are compiled as a proxy for cloud cover. Statistical examination methods based on the Monte Carlo approach are being developed and past statistical studies and their results are being reassessed. Lightning observations from ground and space borne observations related to short-term high-amplitude deviations in CR flux (FD & GLE events) and long-term variations in solar activity are being collected.


T2.2. Data analysis and interpretation

The uncertainties and errors in frequently used satellite cloud datasets are being quantified and the upper detection limit for ionization-induced changes in clouds is being determined, regarding the cloud data quality. This task includes the analysis of diurnal temperature data as a proxy for cloud cover, the synoptic weather data in order to examine the links between long-term solar activity and historical climate records, and lightning observations related to short-term high magnitude deviations in CR flux and long-term variations in solar activity. The Monte Carlo approach is adjusted/advanced to test the significance of current and past studies and long (centennial) timescale associations of climate variability to solar activity are being examined.


T2.3. Analysis of long-term ground-based climatologic measurements

This task is devoted to investigation of cloud properties theoretically optimal for the detection of an observable CR-cloud response, analysis and interpretation of aerosol data related to the CR induced ionization changes in the atmosphere, and search for possible changes in cloud microphysical properties connected to the global electric circuit mechanism. Various climate proxies (which extend more into the past) and parameters are employed to test the solar variability influence on climate and comparison of various theoretical mechanisms of solar influence on climate is preformed.