1. Solar Quasi-Biennial Fluctuations Csilla Szasz and Johan Kero Heliophysical Observatory Debrecen

2. Swedish Institute of Space Physics

4. The Butterfly Diagram of the Present Debrecen Photoheliographic Data (DPD)

6. Umbra-Penumbra Area Ratio for Sunspots in the DPD

7. U/P Area Ratio for Sunspot Groups in the Debrecen Photoheliographic Results (DPR)

8. Mean U/P Area Ratio for Different Sizes of Spots in the DPD  U + P Area < 15  15 ≤ U + P Area < 50  50 ≤ U + P Area < 300

9. U/P Area Ratio as a Function of the Umbra Area  1993 Max  1995 Max  1988 Min  1994 Min

10. PSD Estimate for Monthly Mean U/P Area Ratio (with Subtracted DC-component) 1986 - 19891993 - 1996

11. Best Sinusoidal Fit - T ~ 24.2 months

12. Best Polynomial Fit

13. Possible Physical Interpretations (still under investigation) A fluctuation in the temperature and plasma pressure stratification of the photosphere A quasi-biennial variation of sunspot magnetic configurations

14. Other Mid-Term Periodicities Solar Spectroscopic Temperature Measurements Solar Radius Measurements Sunspot and Sunspot Group Numbers Solar Neutrino Measurements Solar UV Measurements Solar Irradiance Measurements Shear Oscillation of the Solar Tachocline Solar Wind Speed aa-Index of Geomagnetic Activity The Quasi-Biennial Oscillation in the Earth Tropical Stratosphere

16. QBO in the Tropical Stratosphere

18. Composite Irradiance Data

19. 10 Months Moving Average of Irradiance Residuals