Influence of the Precipitating Energetic Particles on Atmospheric Chemistry and Climate

Abstract

We evaluate the influence of the galactic cosmic rays (GCR), solar proton events (SPE), and energetic electron precipitation (EEP) on chemical composition of the atmosphere, dynamics, and climate using the chemistry-climate model SOCOL. We have carried out two 46-year long runs. The reference run is driven by a widely employed forcing set and, for the experiment run, we have included additional sources of NO x and HO x caused by all considered energetic particles. The results show that the effects of the GCR, SPE, and EEP fluxes on the chemical composition are most pronounced in the polar mesosphere and upper stratosphere; however, they are also detectable and statistically significant in the lower atmosphere consisting of an ozone increase up to 3 % in the troposphere and ozone depletion up to 8 % in the middle stratosphere. The thermal effect of the ozone depletion in the stratosphere propagates down, leading to a warming by up to 1 K averaged over 46 years over Europe during the winter season. Our results suggest that the energetic particles are able to affect atmospheric chemical composition, dynamics, and climate.

Solar Influence on Global and Regional Climates

“…It should be noted that they used geomagnetic activity indices as indicators of the probability of SEP fluence, and these correlate highly with the open solar flux F S . Thus, it is likely they are observing the same phenomenon as reported by Lockwood et al (2010a), Woollings et al (2010b) and Bochníček and Hejda (2005) but are using an interpretation based on the model predictions of SEP effects by Rozanov et al (2005Rozanov et al ( , 2012. Similarly, the effect reported by Lu et al (2008) which they attributed to the solar wind could well be via a correlation with open solar flux.…”

“…Chemical and dynamical modelling of the effects of energetic particles has yielded a surface temperature perturbation pattern similar to that shown in Fig. 6 (Rozanov et al 2012).…”

“…Similarly, the effect reported by Lu et al (2008) which they attributed to the solar wind could well be via a correlation with open solar flux. In this context, it is interesting to note that the effects of SEPs may also be caused by other precipitating energetic particles, including GCRs or energetic electrons energised by the solar wind (see review by Rozanov et al 2012, and references therein). Chemical and dynamical modelling of the effects of energetic particles has yielded a surface temperature perturbation pattern similar to that shown in Fig.…”

Solar wind-atmospheric electricity-cloud microphysics connections to weather and climate

“…The relatively short timescale and the apparent upward propagation of this solar-wind-induced effect is in contrast to the downward propagation, on a timescale of months, of meteorological effects to the lower troposphere from the stratosphere due to other mechanisms associated with solar variability involving stratospheric ultraviolet (UV) radiation (e.g., Gray et al, 2010;Ineson et al, 2011;Ermolli et al, 2013) and precipitating energetic particles. Energetic particles, in the form of galactic cosmic rays, solar proton events (SPEs), and energetic electron precipitation from the aurora and the radiation belts associated with geomagnetic storms and substorms, are able to affect atmospheric chemical composition, dynamics, and climate (e.g., Rozanov et al, 2012;Seppälä et al, 2014;Mironova et al, 2015, and the paper by Georgieva et al in this issue).…”

Solar forcing for CMIP6 (v3.2)

“…In particular, the production of odd nitrogen and odd hydrogen species causes changes in ozone abundances via catalytic cycles, potentially affecting temperature and winds (see, e.g., the review by Sinnhuber et al, 2012). Recent model studies and the analysis of meteorological data have provided evidence for a dynamical coupling of this signal to the lower atmosphere, leading to particleinduced surface climate variations on a regional scale (e.g., Seppälä et al, 2009;Baumgaertner et al, 2011;Rozanov et al, 2012;Maliniemi et al, 2014).…”