Dickey JO, Marcus SL, de Viron O, Fukumori I. Recent Earth oblateness variations: unraveling climate and postglacial rebound effects.
Science 2002;
298:1975-7. [PMID:
12471253 DOI:
10.1126/science.1077777]
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Abstract
Earth's dynamic oblateness (J2) has been decreasing due to postglacial rebound (PGR). However, J2 began to increase in 1997, indicating a pronounced global-scale mass redistribution within Earth's system. We have determined that the observed increases in J2 are caused primarily by a recent surge in subpolar glacial melting and by mass shifts in the Southern, Pacific, and Indian oceans. When these effects are removed, the residual trend in J2 (-2.9 x 10(-11) year-1) becomes consistent with previous estimates of PGR from satellite and eclipse data. The climatic significance of these rapid shifts in glacial and oceanic mass, however, remains to be investigated.
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