A systematic study of Schumann resonance parameters during high-energy particle precipitation events is presented. Protons and electrons with energies above 1 MeV ionize the upper boundary of the Earth-ionosphere cavity, leading to an increase of the resonance frequency and a decrease of the damping of the first Schumann resonance, as derived from measurements at Arrival Heights, Antarctica. The study uses the nine strongest solar proton events of the past solar cycle 22 and high-energy electrons emitted periodically from corotating interaction regions in the solar wind during 1994--1995. The variation of the Schumann resonance parameters is in qualitative agreement with current theories of Schumann resonances. The study also shows that high-energy particle precipitation is not the only relevant source affecting Schumann resonance parameters. The reported findings constitute a so far little-explored aspect of solar terrestrial relations. ¿ 1999 American Geophysical Union