Impacts of energetic electron precipitation on the atmosphere: results from a 300-year chemistry-climate model experiment

Many past studies based on climate reanalysis data have strongly indicated that energetic electron precipitation (EEP) from space into the polar atmosphere leads to mesospheric and stratospheric ozone loss. This in turn affects radiative balance in the atmosphere and leads to thermal changes, which enhance the stratospheric polar vortex.

Here we study the EEP influence on the atmosphere and climate system using the SOCOL3-MPIOM chemistry-climate model. We run idealized 300-year long timeslice simulations with (experiment run) and without (control run) EEP forcing. The control run captures the internal variability of the climate system without EEP forcing, while the experiment run depicts the variability of the climate system when it is forced with EEP. The EEP forcing employs a parameterization to represent the influx of NOx molecules through the model top created by low-energy auroral precipitation. We also include the direct ionization produced by EEP evaluated from a new data composite based on POES satellite observations. The model is repetitively forced each year throughout the entire simulation with the EEP forcing observed during winter 2003/2004.

Here we discuss the preliminary findings from these long model runs and show that they confirm the EEP-driven ozone loss and subsequent enhancement of the stratospheric polar vortex.