Impact of Forbush Decreases and Geomagnetic Storms on the Atmospheric Ozone Profiles

Abstract

The geomagnetic field distortions, known as geomagnetic storms, are forced by a shockwave-propagating through the interplanetary medium after the solar flares, coronal mass ejection, high-speed streams, or other active processes on the Sun. The imposed magnetic irregularities reflect or scatter a part of galactic cosmic rays (CRs) traveling through the heliosphere. As a result, the geomagnetic storms are usually accompanied by a significant decrease of the flux of highly energetic particles reaching the Earth. Such short-lasting decreases of CRs' intensity are known as Forbush decreases (FDs). However, FDs are observed also without the occurrence of geomagnetic disturbances. These two events impact the atmospheric chemical composition-and particularly the ozone. Moreover, it is still unclear whether the effect of geomagnetic storm differs from that of the FD, and if so-what are the mechanisms of such an influence on the ozone.Statistical evidence for geomagnetic imprint on the ozone density has been found long ago. Most of the studies, examining geomagnetic storms-ozone relation, are focused on the total ozone density response. The reported results, however, are quite contradictive. Some of the authors claimed ozone depletion during or short after the onset of geomagnetic storms (