The role played by ozone in the lower D region electron density variations in winter

Electron density variability below 70 km, measured by the partial reflection experiment over Ottawa during quiet winter days, shows a remarkably good inverse relationship with the total ozone measured on the previous day over Toronto. Meteorological transport process as a cause of the winter variability is stressed. The role of important minor neutral constituents in the ion chemistry of the lower D region is examined in some detail, and the observed variability in the electron densities well below 70 km seems to be explainable in terms of negative ion chemistry in whose reaction scheme ozone plays a decisive role through atomic oxygen. Near 70 km the negative ion chemistry alone is not sufficient to explain the results.