Speaker
Description
In order to determine the effect of energetic particle forcing on the Earth’s atmosphere over decadal timespans it has been necessary to develop models of energetic electron precipitation (EEP) based on long time-series geomagnetic indices. This has been done using the geomagnetic index, Ap, and recommended for use as one of the solar forcing factors in the Coupled Model Intercomparison Project Phase 6 of the World Climate Research Programme. However, in that process Ap was not selected as a proxy for EEP based on its merit, but for convenience. Here we use the EEP measurements from three different satellite datasets, 2 individual spacecraft and 1 constellation. We look over different observation periods, and use a range of particle detector configurations to test for the ‘best’ proxy; investigating both geomagnetic and solar wind parameters. In all we tested seven different indices to see how good they were as proxies for EEP and found that for medium energy electrons the best proxies were Ap, and Dst – both geomagnetic indices. That is good news for the use of Ap in previous solar forcing modelling. For higher energies, relativistic electron precipitation is best proxied by Kp or AE. This should be considered if and when any solar forcing factors are expanded into these relativistic energies for EEP.
| Solicited or Contributed | Contributed |
|---|---|
| Presenting author | Mark Clilverd |
| Author list and affiliations | Malcolm Crack (1), Craig J. Rodger(1), Mark A. Clilverd (2), and Aaron T. Hendry (1,2) (1) Physics Department, University of Otago, Dunedin, New Zealand. (2) British Antarctic Survey (UKRI-NERC), Cambridge, United Kingdom. |
