SCHUMANN RESONANCE-SPECTRA IN A 2-SCALE-HEIGHT EARTH-IONOSPHERE CAVITY

New expressions are developed for the amplitude and power spectra of t he electric and magnetic components of lightning-excited Schumann reso nances. A classical normal mode approach is used, yielding expressions directly in terms of the complex eigenfrequencies of the Earth-ionosp here cavity. Using previous simplified formulations of the eigenvalue problem in terms of a two-scale-height model of a dissipative Earth-io nospheric cavity, these results permit calculation of spectra in terms of geometric properties of the system. The expressions are in a conve nient form for application in correlation studies involving use of the resonance intensities as a proxy measure of other Earth system parame ters, such as average tropical continental temperature [Williams, 1992 ].