Correlation between some of the meteorological parameters measured during the partial solar eclipse, 11 August 1999

The meteorological parameters: direct solar (DS) and relative ultraviolet solar (UV) irradiances, pressure (p), temperature (T), relative humidity (RH) and negative small air-ion concentration (n), have been measured at Belgrade during the partial (97.7%) solar eclipse on 11 August 1999. Correlation between DS, relative UV irradiances (Pearson's correlation coefficient, r=0.7) and theoretical prediction of insolation drop during the eclipse are presented. The atmospheric pressure was close to normal and practically constant. A “mirror symmetry” between T and RH was observed. Correlation between RH and n (r=0.8) was found and highlighted considering molecular collision processes. This correlation was confirmed in an indoor experiment (r=0.95) and it is related partly to the decrease of air-ion recombination rate with increase of RH during the eclipse.