Three-hourly average values of the Dst, AE and ap geomagnetic activity indices have been studied for 1 year's duration near the solar minimum (1974) and also at the solar maximum (1979). In 1979 seven intense geomagnetic storms (Dst <A100 nT) occurred, whereas in 1974 only three were reported. This study reveals: (1) the yearly average of AE is greater in 1974 than in 1979, whereas the inverse ...

A number of techniques currently in use for predicting solar activity on a solar cycle timescale are tested with historical data. Some techniques, e.g., regression and curve fitting, work well as solar activity approaches maximum and provide a month~by-month description of future activity, while others, e.g., geomagnetic precursors, work well near solar minimum but only provide an estimate of t...

A number of techniques currently in use for predicting solar activity on a solar cycle timescale are tested with historical data. Some techniques, e.g., regression and curve fitting, work well as solar activity approaches maximum and provide a month-by-month description of future activity, while others, e.g., geomagnetic precursors, work well near solar minimum but only provide an estimate of t...