Christine Smith-Johnsen, Birkeland Centre for Space Science Ville Maliniemi, Birkeland Centre for Space Science
Precipitating energetic protons and electrons, ionizing the polar thermosphere and mesosphere, have long been known to initiate a series of chemical reactions increasing the production of NOx and HOx gasses. HOx and NOx gasses will destroy ozone in catalytic reactions, and it is speculated that the subsequent change in temperature might alter stratospheric winds and wave propagation. Model simulations and meteorological reanalysis studies suggest that the energetic particle precipitation (EPP) induced chemical-dynamical coupling could impact regional surface level climate at high latitudes during winter. In order to extend the understanding of the stratospheric ozone variability and its potential link to the surface climate, one has to improve on quantifying the EPP energy input at the different altitude levels of the atmosphere. Over the years different parameterization of auroral and radiation belt particle flux and energy have been suggested. They are parameterized as functions of corrected geomagnetic latitude and sometimes magnetic local time, and their strength is scaled by either Kp, Bz and/or the solar wind velocity. A parameterization enables statistical maps which gives the total energy input due to solar driven particles for time span covered by the proxy parameters. Now, for the first time solar-driven particle impact is part of the recommended solar forcing dataset for Coupled Model Intercomparison Project 6 (CMIP6). The CMIP6 recommendation provide ionization rates to account for effects of solar protons and electrons. The electron ionization rates are scaled by the geomagnetic indices Ap and Kp. Here we present a review on energetic particle fluxes and their parameterization for climate research. We explore the relationship between geomagnetic activity and particle precipitation during different types of activity. In order to assess the accuracy of the CMIP recommended Ap based parameterization, we compare the parameterized electron fluxes with estimates of the loss cone fluxes from MEPED using two directional detectors in combination with electron pitch angle distributions from theory of wave-particle interactions. The objective of this comparison is to understand the potential uncertainty in the EPP impact when applying the CMIP6 parameterization, in order to assess the subsequent impact on the atmosphere.
Mode of presentation: oral (Need to be confirmed by the SOC)