Scientists would like to better understand the physical processes in Amazon hydrological systems.
To explore the water storage and dynamics in the Amazon basin, a team of researchers used four years of data from the two Gravity Recovery and Climate Experiment (GRACE) satellites, which measure mass distribution on Earth's surface through instantaneous measurements of the changes in the distance between the satellites. Water stored in the Amazon basin affects mass distribution and thus can be monitored by the GRACE satellites.
Reporting in a recent issue of Geophysical Research Letters, the authors (Han et al.) found that soil water explains about half of the observed changes in intersatellite distance; surface and subsurface runoff explains the rest. By comparing river runoff routing simulations with GRACE data for the Amazon region, the authors found that the overall effective runoff velocity for the entire Amazon basin was about 30 centimeters per second (about one foot per second), with significant seasonal variation.
They conclude that incorporating GRACE data can help improve routing schemes in large-scale land surface models.
The team included scientists from NASA's Goddard Space Flight Center, the University of Maryland, the University of Tokyo, the Korea Polar Research Institute, and Ohio State University.
- Han, S.-C., H. Kim, I.-Y. Yeo, P. Yeh, T. Oki, K.-W. Seo, D. Alsdorf, and S. B. Luthcke. Dynamics of surface water storage in the Amazon inferred from measurements of inter-satellite distance change. Geophysical Research Letters, 2009; 36 (9): L09403 DOI: 10.1029/2009GL037910
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