@InProceedings{ManziKREONZSCAWKG:2002:LoTeMe,
               author = "Manzi, Antonio Ocimar and Kruijt, B. and Randow, Celso von and 
                         Elbers, J. and Oliveira, P. J. and Nogueira, Jorge L. M. and 
                         Zanchi, F. B. and Silva, R. L. and Cardoso, F. L. and Aguiar, R. 
                         G. and Waterloo, M. and Kabat, P. and Gomes, B. M.",
                title = "The long term measurements of energy and CO{\'y} fluxes over LBA 
                         pasture and forest sites in Rond{\^o}nia",
                 year = "2002",
         organization = "International LBA Scientific Conference, 2.",
             keywords = "METEOROLOGIA, Rond{\^o}nia, medi{\c{c}}{\~a}o, 
                         varia{\c{c}}{\~o}es anuais, energia, oxig{\^e}nio, fluxos, 
                         florestas, measurement, annual variations, energy, oxygen, fluxes, 
                         forests.",
             abstract = "On the scope of BR/EU LBA Flux Tower Consortium, the turbulent 
                         fluxes of sensible and latent heat, CO2 fluxes and general 
                         meteorological variables have been measured continuously in a 
                         forest site (Rebio Jaru, 10.08o S, 61.93o W)and in a pasture site 
                         (Fazenda Nossa Senhora, 10.75§ S; 62.37§ W)in state of Rondonia, 
                         since February 1999. The technique used to measure the fluxes is 
                         the eddy covariance technique. On this work, results from these 
                         three-year measurements are presented. Seasonal variations of 
                         energy and CO2 fluxes are analyzed at both sites. Due to the 
                         higher reflectivity and net long wave loss at pasture than at the 
                         forest, the net radiation is 16 - 22 lower in the pasture, with 
                         the larger differences occurring during dry seasons. The partition 
                         of this energy in sensible and latent heat is also different in 
                         the two vegetation covers and sensitive to the season. Three-month 
                         averaged Bowen ratios (ratio between sensible and latent heat 
                         fluxes)ranged from 0.21 during wet seasons to 0.28 during dry 
                         seasons at forest and from 0.33 (wet season)to 0.81 (dry season)at 
                         the pasture. The major differences between CO2 fluxes at the two 
                         sites also occur during dry seasons, when the humidity of the top 
                         layers of soil is severely reduced. Both the daytime-averaged Net 
                         Ecosystem Exchange (NEE), which is mainly influenced by 
                         photosynthesis activity, and nighttimeaveraged NEE, which is 
                         dominated by respiration, show clear variations between the 
                         seasons, especially at the pasture site, being higher (more 
                         negative in the case of daytime)at the wet seasons. The daily NEE 
                         values, which represent the difference between photosynthesis and 
                         respiration, are negative throughout the year, leading to a high 
                         annual uptake at both sites. At the forest, the annual uptake 
                         ranges from 4 to 6 ton C / ha / year. In the pasture, the 
                         preliminary values are similar, however, a recent analysis 
                         indicate that fluxes might be underestimated in calm nights at 
                         this site. After applying an appropriate filter for 
                         underestimation at low turbulence conditions, final values for the 
                         pasture site will be presented. At the forest, apparently there is 
                         no underestimation of nighttime fluxes in calm nights.",
  conference-location = "Manaus, Br",
      conference-year = "7-10 July 2002",
                label = "10219",
           targetfile = "9299.pdf",
        urlaccessdate = "23 maio 2024"
}