@Article{ZeriAbre:2011:HoVeTu,
               author = "Zeri, Marcelo and Abreu, Leonardo Deane de",
          affiliation = "Univ Illinois, Energy Biosci Inst, Urbana, IL 61801 USA and 
                         {Instituto Nacional de Pesquisas Espaciais (INPE)}",
                title = "Horizontal and Vertical Turbulent Fluxes Forced by a Gravity Wave 
                         Event in the Nocturnal Atmospheric Surface Layer Over the Amazon 
                         Forest",
              journal = "Boundary-Layer Meteorology",
                 year = "2011",
               volume = "138",
               number = "3",
                pages = "413--431",
                month = "MAR",
                 note = "{Setores de Atividade: Pesquisa e desenvolvimento cient¨ªfico.} 
                         and {Informa{\c{c}}{\~o}es Adicionais: Publicado online em 25 de 
                         novembro de 2010...}",
             keywords = "Amazon forest, Downbursts, Gravity waves, Nocturnal surface layer, 
                         Scalar fluxes, Wavelet analysis. BOUNDARY-LAYER, DECIDUOUS FOREST, 
                         RAIN-FOREST, INTERMITTENT TURBULENCE, COHERENT MOTIONS, EXCHANGE, 
                         CANOPY, ENERGY, CARBON, VARIABILITY.",
             abstract = "A nocturnal gravity wave was detected over a south-western Amazon 
                         forest during the Large-Scale Biosphere-Atmosphere experiment in 
                         Amazonia (LBA) in the course of the dry-to-wet season campaign on 
                         October 2002. The atmospheric surface layer was stably stratified 
                         and had low turbulence activity, based on friction velocity 
                         values. However, the passage of the wave, an event with a period 
                         of about 180-300 s, caused negative turbulent fluxes of carbon 
                         dioxide (CO2) and positive sensible heat fluxes, as measured by 
                         the eddy-covariance system at 60 m (¡{\"O}30 m above the tree 
                         tops). The evolution of vertical profiles of air temperature, 
                         specific humidity and wind speed during the wave movement revealed 
                         that cold and drier air occupied the sub-canopy space while high 
                         wind speeds were measured above the vegetation. The analysis of 
                         wind speed and scalars high frequency data was performed using the 
                         wavelet technique, which enables the decomposition of signals in 
                         several frequencies allowed by the data sampling conditions. The 
                         results showed that the time series of vertical velocity and air 
                         temperature were -90¡{\~a} out of phase during the passage of the 
                         wave, implying no direct vertical transport of heat. Similarly, 
                         the time series of vertical velocity and CO2 concentration were 
                         90¡{\~a} out of phase. The wave was not directly associated with 
                         vertical fluxes of this variable but the mixing induced by its 
                         passage resulted in significant exchanges in smaller scales as 
                         measured by the eddy-covariance system. The phase differences 
                         between horizontal velocity and both air temperature and CO2 
                         concentration were, respectively, zero and 180¡{\~a}, implying 
                         phase and anti-phase relationships. As a result, the wave 
                         contributed to positive horizontal fluxes of heat and negative 
                         horizontal fluxes of carbon dioxide. Such results have to be 
                         considered in nocturnal boundary-layer surface-atmosphere exchange 
                         schemes for modelling purposes.",
                  doi = "10.1007/s10546-010-9563-3",
                  url = "http://dx.doi.org/10.1007/s10546-010-9563-3",
                 issn = "0006-8314 and 1573-1472",
                label = "lattes: 0107976161469463 2 ZeriS¨¢:2010:HoVeTu",
             language = "en",
           targetfile = "zeni.pdf",
                  url = "http://www.springerlink.com",
        urlaccessdate = "09 maio 2024"
}