@InCollection{FischCulMalNobNob:2000:CaDiMe,
               author = "Fisch, Gilberto and Culf, A. D. and Malhi, Y. and Nobre, Carlos 
                         Afonso and Nobre, Antonio Donato",
                title = "Carbon dioxide measurements in the nocturnal boundary layer over 
                         Amazonian forest",
            booktitle = "Global climate change and tropical ecosystem",
                 year = "2000",
               editor = "Lal, R. and Kimble, J. M. and Stewart, B. A.",
                pages = "391-- 403",
              address = "Boca Raton",
             keywords = "climatologia, meteorologia.",
             abstract = "Tropical forest represents significant sources/sinks for trace 
                         gases (C02, O], CH4), and the exchange of CO2 between forest and 
                         the atmosphere is an important component of the global carbon 
                         cycle because of its greenhouse effect. The secular increase of 
                         C02 concentration is reasonably well defined (Keeling and Whorf, 
                         1994) but a full comprehension of C02 cycles for different biomes 
                         and its impact on climate and ecology is not well understood. 
                         Baldocchi et al. (1996) have addressed this issue based on the 
                         conclusions of a workshop to discuss the strategies for monitoring 
                         and modeling CO2 fluxes over terrestrial ecosystems. The diurnal 
                         cycle of atmospheric CO2 reflects the exchange of metabolic carbon 
                         between the atmosphere and the vegetation-soil system. The typical 
                         behavior of CO2 concentration shows an increase during the night, 
                         when soil emissions and respiration combine as a source of CO2 to 
                         the atmosphere and start to decrease during mid morning when 
                         atmospheric CO2 is taken up by the vegetation. The nighttime CO2 
                         flux is positive, reversing its sign (to downward) in the early 
                         morning. Although the nighttime CO2 flux above the canopy is a sum 
                         of aIl CO2 released by the vegetation and the soil, the 
                         atmospheric stability near the canopy does not allow mixing 
                         between the rich CO2 air inside canopy and that above it. 
                         Fitzjarrald and Moore (1990) have observed some events (waves) 
                         that occur during the night in the Amazon forest and associate 
                         these events with periods ofhigher turbulent mixing between the 
                         canopy and the atmosphere, leading to increasing of values of C02 
                         exchange. They point out that these events occur on average 5 
                         times during the night with a time interval ranging from 25 to 60 
                         minutes .They also noted that these events happen when the 
                         windspeed above the canopy is typicallyaround 1.8 m S.I. Grace et 
                         al. (1995) noticed that in the early morning there was a higher 
                         flux ofC02 out ofthe canopy due to the onset of turbulence. They 
                         pointed out that the onset of turbulence disrupted the stable 
                         layer at lhe crown, allowing mixing between air, wich has been 
                         accumulating CO2, and the atmosphere. They have called this 
                         phenomena the moming ventilation and it has high values of C02 
                         flux the maximum value observed in tropical forest (at 
                         Rond{\^o}nia) is +20 ?mol m-2s-l.",
          affiliation = "{CPTEC-INPE-Cachoeira Paulista-12630-000-SP-Brasil}",
           copyholder = "SID/SCD",
                 isbn = "1-56670-485-5",
                label = "self-archiving-INPE-MCTIC-GOV-BR",
             language = "en",
          seriestitle = "Advance soil science",
           targetfile = "11747.pdf",
               volume = "1",
        urlaccessdate = "13 maio 2024"
}