Enhancement of stratospheric aerosols after solar proton event

Abstract

Abstract. The lidar measurements at Verhnetulomski observatory (68.6°N, 31.8°E) at Kola peninsula detected a considerable increase of stratospheric aerosol concentration after the solar proton event of GLE (ground level event) type on the 16/02/84. This increase was located at precisely the same altitude range where the energetic solar protons lost their energy in the atmosphere. The aerosol layer formed precipitated quickly (1–2 km per day) during 18, 19, and 20 February 1984, and the increase of R(H) (backscattering ratio) at 17 km altitude reached 40% on 20/02/84. We present the model calculation of CN (condensation nuclei) altitude distribution on the basis of an ion-nucleation mechanism, taking into account the experimental energy distribution of incident solar protons. The meteorological situation during the event was also investigated.

Formation of large NAT particles and denitrification in polar stratosphere: possible role of cosmic rays and effect of solar activity

“…CRIF process appears to provide a direct and more convincing explanation for the high correlation between the thin nitrate-rich layers in polar ice cores and major SPEs (McCracken et al, 2001) and the observed enhancement in aerosol backscattering ratio at PSC layers shortly after the SPE (Shumilov et al, 1996). Fig.…”

“…Analysis of meteorological data indicates that the increase was not associated with temperature change and seems to be caused by the SPE (Shumilov et al, 1996). The mechanism Shumilov et al (1996) offered to explain that the aerosol backscatter ratio enhancement is the increase in aerosol concentration as a result of SPE-induced enhancement in the ion nucleation rate of ultrafine particles. This explanation is questionable because the concentration of sulfuric acid gas in winter polar stratosphere is extremely low (<∼10 5 cm −3 ) and the increase in ionization rate may not lead to an increase in the formation of fresh ultrafine particles (Yu, 2002).…”

“…Thus, the high correlations between the nitrate-rich layers in polar ice cores and major solar proton events (McCracken et al, 2001) might support the CRIF mechanism. Shumilov et al (1996) reported a considerable increase in the aerosol backscatter ratio after a strong SPE. Analysis of meteorological data indicates that the increase was not associated with temperature change and seems to be caused by the SPE (Shumilov et al, 1996).…”

“…Shumilov et al (1996) reported a considerable increase in the aerosol backscatter ratio after a strong SPE. Analysis of meteorological data indicates that the increase was not associated with temperature change and seems to be caused by the SPE (Shumilov et al, 1996). The mechanism Shumilov et al (1996) offered to explain that the aerosol backscatter ratio enhancement is the increase in aerosol concentration as a result of SPE-induced enhancement in the ion nucleation rate of ultrafine particles.…”

Cosmic ray-induced stratospheric aerosols: A possible connection to polar ozone depletions

“…The mechanism of the ion nucleation through the ionization process has been developed by Arnold (1982) as a potential source of condensation nuclei (CN) on which stratospheric sulfate aerosols can form (Arnold, 1982;Hofman and Rosen, 1983). Shumilov et al (1995Shumilov et al ( , 1996 reported that high-energy (150-300 MeV) solar protons can contribute to aerosol layer and initiate ozone "mini-holes" at high latitudes. Taking into account that the low (less than −78 • ) stratospheric temperatures are rare in occurrence at northern polar latitudes (10% days in a year) (Taalas and Kyro, 1992), we consider the solar protons as one of the possible agents influencing the ozone layer and aerosols in Arctic.…”