Bowie Lecture: Time-Variable Gravity Measurements Come of Age

Geodesy [G]

G24A MCC:3001 Tuesday 1710h

Presiding:O de Viron, Royal Observatory of Belgium; B F Chao, NASA Goddard Space Flight Center

G24A-01 INVITED 17:15h

Bowie Lecture: Time Variable Gravity Measurements Come of Age

* Watkins, M M (michael.watkins@jpl.nasa.gov) , Jet Propulsion Laboratory, California Institute of Technology, MS T1723-118, Pasadena, CA 91109

The Earth and planetary science and geodesy communities have long recognized measurements of the static gravity field as primary for understanding bulk properties and formation histories. Use of the time varying field, however, to measure the cycling of volatiles has been only coarsely demonstrated over the past two decades. The GRACE mission has now realized the promise of those early studies and demonstrated that gravity field measurement is now a valid remote sensing concept for the Earth and eventually other planets in the solar system. We will discuss the latest GRACE results for the measurement of the Earth's water cycle on land, the oceans, and ice sheets, and outline prospects and capabilities of follow-on missions. We will conclude with an overview of the recent exciting results of both current and proposed planetary missions, especially at Mars, for time varying gravity measurements outside the Earth as well.