New paper describes another solar amplification mechanism via cosmic rays

A paper published today in Advances in Space Research describes another mechanism by which variations in galactic cosmic rays can have significant atmospheric effects. Svensmark's cosmic ray theory of climate explains how solar activity modulates galactic cosmic rays, which in turn may affect cloud formation. This new paper finds another solar amplification mechanism by which small changes in solar activity and cosmic rays affect atmospheric pressure, and cyclone & anticyclone activity.

The authors find that Forbush decreases, a rapid decrease in galactic cosmic ray intensity following a solar coronal mass ejection, cause "noticible pressure variations...at extratropical latitudes of both hemispheres" and "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 [pressure] systems and play an important role in solar-terrestrial relationships."

Fig. 5. 

Mean variations of zonal geopotential height of the 1000 hPa level on the 4^th day after the onset of Forbush decreases in the Northern and Southern hemispheres.

Atmospheric Pressure Variations at Extratropical Latitudes Associated with Forbush Decreases of Galactic Cosmic Rays

• I. Artamonova^a, , , 
• S. Veretenenko^a, b, 

• ^a St.Petersburg State University, St.Petersburg, 198504, Russia
• ^b Ioffe Physical-Technical Institute, St.Petersburg, 194021, Russia

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Abstract

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 to 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.