Un-decimated discrete wavelet transform based algorithm for extraction of geomagnetic storm sudden commencement onset of high resolution records

The automatic detection of the onset time of the geomagnetic storm sudden commencement (SSC) is of great importance for many applications. The distribution of the power along the frequency axis during the SSC was investigated. This analysis guide us to build an SSC automatic detector, for the first time, of one sample per second data based on the un-decimated discrete wavelet transform (DWT), unlike previous studies that focused on determining the SSC times using one-minute resolution data. Using such high-resolution data enabled us to achieve a small detection error and short processing time. One hundred thirty four geomagnetic storms were considered for testing the proposed algorithm; it was found that the average and maximum standard deviation of the errors in the detection times determined by the algorithm were 35 and 44 s, respectively, of the corresponding manually determined onset times. The proposed algorithm tested by using continuous period data (six months). The results show the capability of the algorithm to detect the SSCs successfully with low rate of false detections.

► SSC spectrum contains high power components over all frequency ranges. ► For the first time, SSC automatic detector uses high resolution data is introduced. ► Small detection error and processing time could be achieved using 1-s data. ► Un-decimated DWT was very useful in SSC automatic detection.