Speaker
Description
Precipitation of energetic particles (often referred to as EPP) from solar or magnetospheric origin into the earth polar atmosphere has long been recognized as an important forcing of the chemical budget of the middle atmosphere. Its impact on atmospheric trace gases such as ozone, nitrogen and hydrogen oxides (NO$_\mathrm{x}$ and HO$_\mathrm{x}$), and chlorine species, has been identified. More controversial is the potential feedback of the EPP-induced ozone losses on the dynamics of the middle atmosphere and of the troposphere, and ultimately on surface climate.
Re-analyses such as ERA-40, MERRA-2, and JRA-55 have been widely used for the research on EPP-induced climate signals of wind and temperature. The advancement of reanalysis datasets, undertaken by multiple meteorological agencies worldwide under the framework of the Atmospheric Processes and Their Role in Climate (APARC) project, has extended the upper boundary of atmospheric reanalyses from the stratosphere into the mesosphere. The ISSI team ‘Dynamical signatures of energetic particle precipitation in atmospheric re-analyses’ primarily re-assesses the ozone, temperature and potential dynamical signatures of EPP from the mesosphere down to the troposphere in existing, state-of-the-art global atmospheric re- analyses. Meanwhile, complementary case study simulations with WACCM-X, WACCM-D and SIC help quantifying the impact of extreme geomagnetic activities on atmospheric composition, thermal structure, and circulation. In this presentation, we report published and preliminary results from the team, spanning tidal variability, compositional changes, and their associated dynamical responses across multiple atmospheric layers, based on model simulations and reanalysis datasets.