The Earth-Atmosphere Momentum Budget: Remaining Discrepancies at High and Low Frequencies
In recent years, it has been well established that the (axial) angular momentum of the atmosphere and that of the solid earth are closely related on a variety of time scales. On the subseasonal scale, for example, 30–50 day atmospheric fluctuations are strongly mirrored in the rotation of the earth (Langley et al., 1981). On seasonal scales, annual and semiannual cycles in the momentum of the atmosphere are matched by those of the earth (Rosen and Salstein, 1985). At inter- annual time scales, features such as the El Nino-Southern Oscillation (ENSO) and the stratospheric quasi-biennial oscillation have been shown to be related to the earth’s rotation rate (Rosen et al., 1984; Chao, 1989). However, on the very shortest and longest time scales the atmospheric and geodetic momentum series appear to diverge, even when measured by the most recent techniques. The purpose of this note is to outline the character of the disagreement at these two time scales. A fuller discussion, including details of our analysis methods, appears in Rosen et al. (1990).
KeywordsCoherence Assimilation Rosen
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