Extreme space weather: some considerations preceding an accurate forecasting

Abstract:

Extreme space weather has been considered as a hazard for nowadays society, but the term ‘extreme space weather’ is not properly defined. X-type solar flares, solar energetic particle events with a large peak flux or a large fluence, large Kp or Dst values are some of the events included in the ‘extreme’ space weather. Nevertheless, these events do not always happen together, as shown, for example, during the largest geomagnetic storm of the present solar cycle, which happened without any X- or even M-flare. Moreover, large Dst or Kp values occurred without any reported failure in capacities which were considered as vulnerable to space weather.

This presentation proposes some considerations which should be taken into account before dealing with an accurate forecasting. These considerations include: (1) a proper definition for the term ‘extreme’ space weather involving the affected user; (2) the proper physical magnitude that is the proxy to forecast for that user need to be determined; (3) the threshold for the magnitude to be considered extreme has to be established; (4) the capacity of a statistical-based approach should be questioned; and (5) the relevance of time-scale and local-scale in the modeling approach needs to be considered.