The application of an advanced spectral estimation procedure, the multitaper method, to time series of stratospheric field variables is explored. New information on inherent cyclic variations is extracted from the time series of total ozone at Reykjav¿k, local 30 hPa temperatures and the equatorial zonal winds. Apart from the annual component, strong signatures of 8.6 months periodicity appear in the Dobson data for the period 1978 to 1990. The same harmonic component is successfully detected in the data from the total ozone mapping spectrometer (TOMS) and the longer term equatorial zonal winds, implying a low latitude dynamically induced cyclic variation of global significance. A spurious semi-annual signal detected in the Dobson data is due to the non-homogeneous sampling rate of the instrument throughout the year. The amplitude and phase of both the annual and 8.6 months line components of the Dobson and TOMS time series show excellent agreement. ¿ American Geophysical Union 1995