Using GRACE Gravimetry and Satellite Altimetry for water Storage studies in the Amazon Drainage Region.
Ole Andersen(1) , Frank Lemoine(2) , and Philippa Berry(3)
Danish National Space Center,
Juliane Maries vej 30,
Dk-2100 Copenagen O,
(2) NASA GSFC, , Greenbelt, MO 20770, United States
(3) De Montford University, The Arch, Leiceister, United Kingdom
We have jointly analysed GRACE and Satellite altimetry over the Amazon River Basin in order to resolve time-variable hydrological changes. The GRACE gravity changes are analysed using a local mascon approach derived by NASA/GSFC. In this approach it is possible to solve for mass change at 10-day intervals using 4 deg X 4 deg blocks from GRACE level 1B data.
Satellite altimetry over the region from especially ENVISAT and JASON-1 has been processed using the EARRS Expert-retracker System. The system recovers substantially more accurate altimetry data over lakes than traditional altimetric data processing.
By combining the mass change estimated by GRACE with the observed lake level height we could both validate the two sets of observations. However, it is also possible to resolve the hydrological change in terrestrial water storage and changes in the observed lake volume.
Data from 2002 through 2004 have been studied to investigate hydrological changes on monthly to inter-annual time scales.