THE EFFECT OF WINDS AND BODILY TIDES ON THE ANNUAL VARIATION IN THE LENGTH OF DAY

Abstract

The effect of winds is to vary the length of day by 0.7 milliseconds between February and August. The bodily tides result largely in a semiannual variation of 0.4 ms. The combined effect of winds and tides is not far out of line with astronomical measurements since 1950. The fluid core of the Earth hardly participates in these variations in angular velocity and there is a half-year slippage of 23 metres between core and mantle at the equator. Eventually the astronomical measurements may provide a basis for determining the Love number h.