1 Simulation of Surface Fluxes in Two Distinct Environments along a Topographic 1 Gradient in a Central Amazonian Forest using the INtegrated LAND Surface Model 2 3 Elisângela Broedel 1 , Celso von Randow 1 , Luz Adriana Cuartas 2 , Antônio Donato Nobre 6 , Alessandro Carioca de 4 Araújo 4 , Bart Kruijt 3 , Etienne Tourigny 5 , Luiz Antônio Cândido 6 , Martin Hodnett 7 , Javier Tomasella 1 5 6 1 Earth System Science Center, National Institute for Space Research (INPE), São José dos Campos, Brazil. 7 8 2 Brazilian Center for Monitoring and Warning of Natural Disasters (CEMADEN), São José dos Campos, Brazil. 9 10 3 Alterra Research Institute, Wageningen University, Wageningen, Netherlands. 11 12 4 Brazilian Agricultural Research Corporation (EMBRAPA), Belém, Brazil. 13 14 5 Barcelona Supercomputing Center (BSC),Barcelona, Spain. 15 16 6 Large Scale Biosphere-Atmosphere Experiment in Amazônia (LBA), National Institute for Amazonian Research (INPA), 17 Manaus, Amazonas, Brazil. 18 19 7 Centre for Ecology and Hydrology, Wallingford, Oxfordshire, United Kingdom. 20 21 22 Abstract 23 The Integrated Land Surface model (INLAND) land surface model, in offline mode, was 24 adjusted and forced with prescribed climate to represent two contrasting environments along a 25 topographic gradient in a central Amazon Terra Firme forest, which is distinguished by well- 26 drained, flat plateaus and poorly drained, broad river valleys. To correctly simulate the valley 27 area, a lumped unconfined aquifer model was included in the INLAND model to represent the 28 water table dynamics and results show reasonable agreement with observations. Field data 29 from both areas are used to evaluate the model simulations of energy, water and carbon 30 fluxes. The model is able to characterize with good accuracy the main differences that appear 31 in the seasonal energy and carbon partitioning of plateau and valley fluxes, which are related 32 to features of the vegetation associated with soils and topography. The simulated latent heat 33 flux (LE) and net ecosystem exchange of carbon (NEE), for example, are higher on the 34 plateau area while at the bottom of the valley the sensible heat flux (H) is noticeably higher 35 than at the plateau, in agreement with observed data. Differences in simulated hydrological 36 fluxes are also linked to the topography, showing a higher surface runoff (R) and lower 37 evapotranspiration (ET) in the valley area. The different behavior of the fluxes on both annual 38 Hydrol. Earth Syst. Sci. Discuss., doi:10.5194/hess-2017-203, 2017 Manuscript under review for journal Hydrol. Earth Syst. Sci. Discussion started: 24 April 2017 c  Author(s) 2017. CC-BY 3.0 License.