The Temporal Variations in Sunspot Number, Geomagnetic aa index and Southern Oscillation Index

A study of three monthly solar-terrestrial indices of mean sunspot number, geomagnetic aa index, and Southern Oscillation Index during period of 1882 to 2000 was carried out to find any consistent short -term periodicities. We found 19, 22, and 26-month periodicities persistently occur in the above data, instead of 11year pattern. We suggest that they might have solar activity origin.