New real-time auroral activity index from geomagnetic measurements

Tiera Laitinen - Finnish Meteorological Institute, Finland; Atte Kapanen - Finnish Meteorological Institute, Finland; Kirsti Kauristie - Finnish Meteorological Institute, Finland; Ari Viljanen - Finnish Meteorological Institute, Finland

Session: R20 and development of services

Abstract

We have developed a new local geomagnetic index for nowcasting the probability of visible auroras. We used 463 hours of all-sky camera images, which were visually classified as containing bright auroras, only weak auroras or a dark sky. This data was compared statistically against several index candidates describing geomagnetic variations as measured by a co-located magnetometer. After selecting the final formula for the index, we determined its threshold values for three observation sites in Finland. We plan to implement this new auroral index as a public real-time nowcast service.