Ozone “miniholes” initiated by energetic solar protons

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

“…Previously it was shown (Shumilov et al, 1995) that OTC depletions observed during 29 September 1989 and May 1990 GLEs could not be explained using only the homogeneous photochemical model introduced by Crutzen et al (1975). Our calculations of OTC depletions based on additional HOx and NOx production during solar proton events (Crutzen et al, 1975;Jackman et al, 1980) were one order of magnitude less than the observed ones (Shumilov et al, 1995).…”

“…Our calculations of OTC depletions based on additional HOx and NOx production during solar proton events (Crutzen et al, 1975;Jackman et al, 1980) were one order of magnitude less than the observed ones (Shumilov et al, 1995). This fact by no means implies that gas-phase photochemical theory only cannot be used to interpret ozone "mini-hole" creation during GLEs.…”

“…A detailed scheme illustrating the ion-catalyzed nucleation of new ultrafine particles from trace condensable vapors (H 2 SO 4 and H 2 O) in the atmosphere, which may then grow into new cloud condensation nuclei (CCN), is performed in Carslaw et al (2002) ;Yu, (2002). We propose that ion nucleation and aerosol enhancement may play a significant role in ozone "minihole" creation at high latitudes after GLEs (Shumilov et al, 1995(Shumilov et al, , 2003. This result seems to correlate with the detection of large increases of stratospheric aerosols in the Arctic (∼17 km altitude) after the occurrence of GLEs (Shumilov et al, 1996).…”

“…Analysis of experimental data and model calculations permits us to explain some distinctions observed in ozone total content (OTC) variations during several GLEs. For example, model simulations show a significant CN concentration enhancement during the May 1990 GLEs of relatively "moderate" magnitude, when polar ozone "miniholes" (OTC depletions up to 20%) have been observed, while no OTC variations and considerable aerosol enhancements were seen during more powerful GLEs (4 August 1972, 2 May 1998, 14 July 2000) (Reagan et al, 1981;Shumilov et al, 1995Shumilov et al, , 2003). Our results demonstrate that "moderate" GLEs may increase aerosol content significantly and cause ozone "mini-hole" creation.…”

“…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.…”