03241naa a2200433 a 450000100080000000500110000800800410001902400430006010000230010324501330012626000090025952020170026865000130228565000150229865000200231365000190233365000230235265000210237565000240239665000160242065000220243670000180245870000140247670000140249070000180250470000190252270000210254170000260256270000170258870000230260570000180262870000180264670000140266470000190267870000130269770000180271070000190272877300600274721591422023-12-04       2021    bl uuuu     u00u1 u    #d7 ahttps://doi.org/10.1111/gcb.155552DOI1 aRESTREPO-COUPE, N.  aUnderstanding water and energy fluxes in the AmazoniabLessons from an observation-model intercomparison.h[electronic resource]  c2021  aTropical forests are an important part of global water and energy cycles, but the mechanisms that drive seasonality of their land-atmosphere exchanges have proven challenging to capture in models. Here, we (1) report the seasonality of fluxes of latent heat (LE), sensible heat (H), and outgoing short and longwave radiation at four diverse tropical forest sites across Amazonia-along the equator from the Caxiuanã and Tapajós National Forests in the eastern Amazon to a forest near Manaus, and from the equatorial zone to the southern forest in Reserva Jaru; (2) investigate how vegetation and climate influence these fluxes; and (3) evaluate land surface model performance by comparing simulations to observations. We found that previously identified failure of models to capture observed dry-season increases in evapotranspiration (ET) was associated with model overestimations of (1) magnitude and seasonality of Bowen ratios (relative to aseasonal observations in which sensible was only 20%-30% of the latent heat flux) indicating model exaggerated water limitation, (2) canopy emissivity and reflectance (albedo was only 10%-15% of incoming solar radiation, compared to 0.15%-0.22% simulated), and (3) vegetation temperatures (due to underestimation of dry-season ET and associated cooling). These partially compensating model-observation discrepancies (e.g., higher temperatures expected from excess Bowen ratios were partially ameliorated by brighter leaves and more interception/evaporation) significantly biased seasonal model estimates of net radiation (Rn), the key driver of water and energy fluxes (LE ~ 0.6 Rn and H ~ 0.15 Rn), though these biases varied among sites and models. A better representation of energy-related parameters associated with dynamic phenology (e.g., leaf optical properties, canopy interception, and skin temperature) could improve simulations and benchmarking of current vegetation-atmosphere exchange and reduce uncertainty of regional and global biogeochemical models.  aAmazonia  aEcosystems  aEddy covariance  aEnergy balance  aEvapotranspiration  aTropical forests  aBalanço de Energia  aEcossistema  aFloresta Tropical1 aALBERT, L. P.1 aLONGO, M.1 aBAKER, I.1 aLEVINE, N. M.1 aMERCADO, L. M.1 aARAUJO, A. C. de1 aCHRISTOFFERSEN, B. O.1 aCOSTA, M. H.1 aFITZJARRALD, D. R.1 aGALBRAITH, D.1 aIMBUZEIRO, H.1 aMALHI, Y.1 aRANDOW, C. von1 aZENG, X.1 aMOORCROFT, P.1 aSALESKA, S. R.  tGlobal Change Biologygv. 27, n. 9, p. 1802-1819, 2021.