Using reanalysis data averaged over river basins in the Americas (the Mackenzie, Mississippi, Amazon and LaPlata basins), we will compare the surface water and energy budgets on the diurnal, daily and annual timescales from the new GMAO reanalysis known as GEOS-5/MERRA (Modern Era Retrospective-analysis for Research and Applications; http://gmao.gsfc.nasa.gov/merra/) with the ECMWF reanalysis, known as ERA-40. We will compare differences in systematic biases and the coupling of land-surface processes to the cloud and radiation fields.