Abstract
Study of periodicities in solar and geomagnetic parameters has been useful in relating solar variability to variations in other phenomena in order to search for the solar cause of, and effects in, the variability observed in near earth space environment. Implementing wavelet analysis on daily, monthly and yearly time resolution data of sunspot number and geomagnetic aa-index, we observed periodicities of 27.8-, 157-, 370-days, and 2.2-, 5.5-, 11-, 22.7-, 38.6-years in the sunspot spot number and 13.8-, 26.6-, 185-days, and 5.3-, 11-, 30-, 46-years in the geomagnetic aa-index. We discuss these periodicities, relation between solar and geomagnetic periodicities and their implications for near-earth space environmental effects. (C) 2014 Elsevier Ltd. All rights reserved.