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Solar Quasi-Biennial Fluctuations. Csilla Szasz and Johan Kero. Heliophysical Observatory Debrecen. Swedish Institute of Space Physics. The Butterfly Diagram of the Present Debrecen Photoheliographic Data (DPD). Umbra-Penumbra Area Ratio for Sunspots in the DPD.
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Solar Quasi-BiennialFluctuations Csilla Szasz and Johan Kero Heliophysical Observatory Debrecen
The Butterfly Diagram of the Present Debrecen Photoheliographic Data (DPD)
U/P Area Ratio for Sunspot Groups in the Debrecen Photoheliographic Results (DPR)
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
U/P Area Ratio as a Function of the Umbra Area • 1993 Max • 1995 Max • 1988 Min • 1994 Min
PSD Estimate for Monthly Mean U/P Area Ratio (with Subtracted DC-component) 1986 - 1989 1993 - 1996
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
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