title: Recent Earth oblateness variations: unraveling climate and postglacial rebound effects.
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.
authors.affiliation: Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA. jean.o.dickey@jpl.nasa.gov
authors.forename: Jean O
authors.initials: JO
authors.lastname: Dickey
authors.forename: Steven L
authors.initials: SL
authors.lastname: Marcus
authors.forename: Olivier
authors.initials: O
authors.lastname: de Viron
authors.forename: Ichiro
authors.initials: I
authors.lastname: Fukumori