Forbush Decreases Of Galactic Cosmic Rays Research Articles

Comparative analysis of short-term effects of solar and galactic cosmic rays on the evolution of baric systems at middle latitudes

Effects of solar proton events (SPEs) and Forbush decreases of galactic cosmic rays (GCRs) on the evolution of baric systems at middle latitudes are compared. It is shown that SPEs with particle energies >90МeV contribute to more intensive regeneration of cyclones at Arctic fronts, while Forbush decreases of GCRs are accompanied by intensification of anticyclonic processes at Polar fronts. The data show that changes in the ionization rate caused by cosmic ray variations play an important part in solar-atmospheric relationships.

Analysis of lower atmosphere pressure field response for short-time cosmic ray variations by Multifield Comparison Measure method

Pressure variation in lower atmosphere which take place after intensive solar proton events and Forbush-decreases of galactic cosmic rays (GCRs) are analyzed for the period 1980-2006. There were plotted groups of charts (multifields) for 48 solar proton events with energies of particles Ep > 90 MeV and for 48 Forbush-decreases of GCRs with amplitudes dN/N > 2.5%. These multifields revealed a growth of matrix norm over North Atlantic region and North of European part of Russia during days following the bursts of solar protons and Forbush-decreases of GCRs, respectively. These results confirm hypothesis about relation of regional cyclogenesis processes with short-term variations of solar and galactic cosmic rays.

Atmospheric pressure variations at extratropical latitudes associated with Forbush decreases of galactic cosmic rays

Changes of troposphere pressure associated with short-time variations of galactic cosmic rays (GCRs) taking place in the Northern hemisphere’s cold months (October–March) were analyzed for the period 1980–2006, NCEP/NCAR reanalysis data being used. Noticeable pressure variations during Forbush decreases of GCRs were revealed at extratropical latitudes of both hemispheres. The maxima of pressure increase were observed on the 3rd–4th days after the event onsets over Northern Europe and the European part of Russia in the Northern hemisphere, as well as on the 4th–5th days over the eastern part of the South Atlantic opposite Queen Maud Land and over the d’Urville Sea in the Southern Ocean. According to the weather chart analysis, the observed pressure growth, as a rule, results from the weakening of cyclones and intensification of anticyclone development in these areas. The presented results suggest that cosmic ray variations may influence the evolution of extratropical baric systems and play an important role in solar-terrestrial relationships.

Cloudiness decreases associated with Forbush-decreases of galactic cosmic rays

Variations of the amount of cloud following Forbush-decreases of the galactic cosmic ray flux have been investigated in different latitudinal belts. It has been found that decreases of the total cloud cover are most distinctly seen in the latitudinal belt ϕ ∼ 60–64°, and disappear at lower latitudes. In the auroral zone:, the apparent effects are weaker than in the subauroral zone. The cloudiness variations associated with the Forbush-decreases are shown to correlate mainly with the presence of cirrus clouds, at heights reached by protons with energy ∼ 1000 MeV.