Observing the ocean water cycle with GRACE

Don Chambers, University of Texas at Austin
R Steven Nerem, University of Colorado Boulder
J Wahr, University of Colorado Boulder

San Francisco, CA

Abstract

Monthly estimates of the Earth's gravitational field from the GRACE mission are used to construct a time-series of global mean ocean mass variations between August 2002 and August 2004. We discuss the methods used to convert gravity coefficients into water mass variations, pointing out several important corrections. The GRACE observations show a clear seasonal exchange of water mass with the continents ( amplitude ~8.5 mm, phase maximum in early- to mid-October). The largest continental contributors to the ocean mass variability are discussed. Using two years of observations, we begin to examine interannual variability, with comments on observing trends in eustatic sea level change.