Photochemical response of neutral and ionized middle atmosphere composition to the strong solar proton event of October 1989

Short- and medium-term atmospheric constituent effects of very large solar proton events

“…The most pronounced atmospheric effects were caused by the very largest SPEs in this period and are concentrated in the polar regions. The four largest SPEs in the past 45 years (August 1972;October 1989; have satellite instrument observations of atmospheric changes with which to compare. Generally, there is reasonable agreement between the WACCM3 predictions and the observations, especially for SPE-caused NO x enhancements and ozone depletion.…”

“…Warneck, 1972;Swider and Keneshea, 1973;Crutzen et al, 1975;Swider et al, 1978;Banks, 1979;Fabian et al, 1979;Jackman et al, 1980Jackman et al, , 1990Jackman et al, , 1993Jackman et al, , 1995Jackman et al, , 2007Rusch et al, 1981;Solomon et al, , 1983Reagan et al, 1981;Jackman and McPeters, 1985;Roble et al, 1987;Reid et al, 1991;Vitt and Jackman, 1996;Vitt et al, 2000;Krivolutsky et al, 2001Krivolutsky et al, , 2003Krivolutsky et al, , 2005Krivolutsky et al, , 2006Verronen et al, 2002Verronen et al, , 2006Semeniuk et al, 2005). Most of these studies were carried out with lower dimensional models (0-D, 1-D, 2-D); however, a few used three-dimensional (3-D) models (e.g.…”

“…For example, Jackman et al (1993Jackman et al ( , 1995 studied the October 1989 SPEs; Semeniuk et al (2005) and Jackman et al (2007) investigated the October/November 2003 SPEs;and Krivolutsky et al (2006) considered the July 2000 SPE. The purpose of this work is to use WACCM3 to investigate the global effects of four very large SPE periods over solar cycles 20-23 (years 1963-2005), namely, the August 1972, October 1989 SPEs. The atmosphere was undergoing substantial changes from 1963-2005 with ground chlorine source gas amounts increasing from about 0.9 to 3.3 ppbv and ground carbon dioxide amounts increasing from about 317 to 380 ppmv.…”

“…This investigation will focus on the short-and mediumterm (days to months) atmospheric influence caused by the very large SPE periods in August 1972, October 1989. We will compare our WACCM3 predictions with observations from several satellite instruments documenting SPE effects during these four periods.…”

“…The very largest SPEs were found to be the most important and caused atmospheric effects that lasted several months after the events. We present the short-and medium-term (days to a few months) atmospheric influence of the four largest SPEs in the past 45 years (August 1972;October 1989; as computed by WACCM3 and observed by satellite instruments. Polar mesospheric NO x (NO+NO 2 ) increased by over 50 ppbv and mesospheric ozone decreased by over 30% during these very large SPEs.…”