This study compares the atmospheric reanalyses that have been produced independently at the Data Assimilation Office (DAO) of Goddard Laboratory for Atmospheres and at the National Centers for Environmental Prediction (NCEP). These reanalyses were produced by using a frozen state-of-the-art version of the global data assimilation system developed at these two centers. For the period 1987-88 and for the tropical oceanic regions of 30 o S-30 o N, surface and atmospheric fields related to atmospheric hydrology and radiation are compared and assessed, wherever possible, with satellite data. Some common biases as well as discrepancies between the two independent reassimilation products are highlighted. The authors note an underestimation of the total precipitable water and an overestimation of the shortwave cloud radiative forcing in warm convective regions. Surface latent and sensible heat fluxes differ by about 20 and 3 W m - 2 , respectively, in the two reanalyses. Differences in the surface radiation budget are larger than the uncertainties of satellite-based estimates.