Copyright WDC C1 for STP at RAL.
DST stands for the Equatorial Disturbance Storm Time Index. This dataset is in the form of an array of hourly index values together with the daily average for years 1957 through to 1994. The data was prepared by M. Sugiura and T. Kamei (from WDC-C2 for Geomagnetism, Faculty of Science, Kyoto University) and associates from NASA.
DST (Disturbance Storm Time) equivalent equatorial magnetic disturbance indices are derived from hourly scalings of low-latitude horizontal magnetic variations. They show the effect of the globally symmetrical westward flowing high altitude equatorial ring current which causes the "main phase" depression worldwide in the H-component field during large magnetic storms.