El Nino impact on atmospheric polar motion excitation

We study the influences of El Nino phenomena on correlations between short- period variations of atmospheric and geodetic excitation functions of polar motion during 1980 - 1998. The correlation between these two excitation fu nctions varies with time, with correlation coefficients computed for 1 year spans reaching maxima of 0.7-0.8. Series of these correlation coefficients themselves correlate with El Nino and Southern Oscillation Index (SOI) dat a, indicating the influence of El Nino and SOI on atmospheric and geodetic excitation functions of polar motion and on polar motion itself. The maximu m correlation coefficients for Nino 4 sea surface temperature data is equal to 0.8 in the case of El Nino events in 1983 and 1987. Impacts of El Nino on polar motion have an impulsive character causing irregular variations of polar motion during the El Nino epochs.