This is subset of the data from MIRACLE iCCD all-sky imagers operated by Finnish Meteorological Institute (FMI) and Sodankylä Geophysical Observatory (SGO), University of Oulu. This subset includes 142 events with wave like aurora forms from FMI's internal Selected ASC data set collected from the MIRACLE database. The subset is used in paper: "Radio emissions reveal Alfvénic activity and electron acceleration prior to substorm onset" by S. Y. Wu et al., Nature Communications (accepted 2025). The original images have been captures with a fish-eye lens. They have been stored in 8-bit gray-scale JPG format, have a size of 512 × 512 pixels, corresponding to an average spatial resolution of approximately 1 km near the zenith at an ionospheric height of 110 km. The images captured with 557.7nm narrow-band filter with a cadence of approximately 20 seconds . Observations were collected from five stations: Abisko (ABK) at geographic latitude 68.36°N and geographic longitude 18.82°E, Muonio (MUO) at 68.02°N 23.53°E, Kevo (KEV) at 69.76°N 27.01°E, Kilpisjärvi (KIL) 69.02°N and 20.87°E, and Sodankylä (SOD) 67.42°N 26.39°E. The iCCD imagers at Kilpisjärvi, Kevo, Abisko and Muonio were owned and operated by Finnish Meteorological Institute. The iCCD imager at Sodankylä was owned and operated by Sodankylä Geophysical Observatory, University of Oulu. The image orientation calibrations are made at FMI. More details about MIRACLE and the iCCD imagers see: https://space.fmi.fi/MIRACLE/ASC/index.php

2025