HR: 14:10h
AN: G23A-03    [Abstracts]
TI: Time Variable Gravity from Local Mascon Analysis of GRACE Data
AU: * Lemoine, F G
EM: Frank.Lemoine@gsfc.nasa.gov
AF: Laboratory for Terrestrial Physics, NASA Goddard Space Flight Center, Greenbelt, MD 20771 United States
AU: Luthcke, S B
EM: Scott.B.Luthcke@nasa.gov
AF: Laboratory for Terrestrial Physics, NASA Goddard Space Flight Center, Greenbelt, MD 20771 United States
AU: Klosko, S M
EM: Steven_M_Klosko@raytheon.com
AF: Laboratory for Terrestrial Physics, NASA Goddard Space Flight Center, Greenbelt, MD 20771 United States
AU: Klosko, S M
EM: Steven_M_Klosko@raytheon.com
AF: Raytheon ITSS, 1616 McCormick Drive, Lanham, MD 20774 United States
AU: Rowlands, D D
AF: Laboratory for Terrestrial Physics, NASA Goddard Space Flight Center, Greenbelt, MD 20771 United States
AU: Chinn, D S
AF: Laboratory for Terrestrial Physics, NASA Goddard Space Flight Center, Greenbelt, MD 20771 United States
AU: Chinn, D S
AF: Raytheon ITSS, 1616 McCormick Drive, Lanham, MD 20774 United States
AU: McCarthy, J J
AF: Laboratory for Terrestrial Physics, NASA Goddard Space Flight Center, Greenbelt, MD 20771 United States
AU: McCarthy, J J
AF: Raytheon ITSS, 1616 McCormick Drive, Lanham, MD 20774 United States
AU: Cox, C M
AF: Laboratory for Terrestrial Physics, NASA Goddard Space Flight Center, Greenbelt, MD 20771 United States
AU: Cox, C M
AF: Raytheon ITSS, 1616 McCormick Drive, Lanham, MD 20774 United States
AU: Williams, T A
AF: Laboratory for Terrestrial Physics, NASA Goddard Space Flight Center, Greenbelt, MD 20771 United States
AU: Williams, T A
AF: Raytheon ITSS, 1616 McCormick Drive, Lanham, MD 20774 United States
AU: Pavlis, D E
AF: Laboratory for Terrestrial Physics, NASA Goddard Space Flight Center, Greenbelt, MD 20771 United States
AU: Pavlis, D E
AF: Raytheon ITSS, 1616 McCormick Drive, Lanham, MD 20774 United States
AB: We have analyzed GRACE Level 1-B data in 2003 and assessed a new approach for extracting time variable gravity that isolates the gravity signal in both time and space. The Level-1B satellite-to-satellite range rate (KBRR) data and accelerometry are processed in daily arcs using the precise orbit products produced by the GRACE team from GPS to calibrate both the accelerometer and KBRR data. We then adjusted select components of the intersatellite baseline vector for each data segment isolated to the region of interest. Herein, we solved for mass anomalies in 4$^\deg$ x 4$^\deg$ blocks over the Amazon and nearby Atlantic Ocean and estimate mass flux in units of cm of water over each block. We show with this approach that we can recover mass anomalies on a submonthly basis with 10 to 15 day temporal resolution. We discuss the important issues related to this solution, including the size of the mascon blocks, the weight given to the temporal and spatial constraint used to stabalize the solutions, as well as the optimal correlation in time and distance. We compare the the mascon results with solutions obtained from the more standard approach using spherical harmonics and with independent hydrology models and lake data. This technique demonstrates that sub-monthly medium wavelength mass flux phenomena are well sensed by the hyper-precise line of sight velocity data produced from GRACE.
DE: 1214 Geopotential theory and determination
DE: 1219 Local gravity anomalies and crustal structure
DE: 1227 Planetary geodesy and gravity (5420, 5714, 6019)
DE: 1294 Instruments and techniques
SC: Geodesy [G]
MN: 2004 AGU Fall Meeting