A Look at Amazon Basin Seasonal Dynamics with the Biophysical ...

A METHODOLOGICAL APPROACH TO STUDY THE DIFFERENCESBETWEEN THE RESULTS OBTAINED FROM THE SINOP-MT TOWER ANDOTHER LBA TOWERSSérgio Roberto de Paulo (iraesergio@uol.com.br), Nicolau Priante Filho, José de SouzaNogueira, Franklin Anderson de Oliveira Souza, Marcelo Sacardi Biudes e MauroMassao Shiota HayashiUniversidade Federal de Mato Grosso, Av. Fernando Correa da Costa s/n 78060-900George Louis Vourlitis (georgev@csusm.edu) Biological Sciences Program- CaliforniaState University- San Marcos, CA 92096-0001, USAData concerning micrometeorological measurements obtained from towers installed inthe Amazon Forest have indicated a mean carbon absorption rate of 1-6 tC ha -1 yr -1 . Thetower situated in Sinop-MT is an exception. Data from Sinop tower have indicatedequilibrium of carbon flux when a whole year period is considered. The explanation forthe difference between Sinop tower data and the data from the other towers can possiblybe found in the differences of the local ecosystem (the Sinop tower is situated in atransition forest), differences of the methodological procedures employed in Sinop (adifferent running mean, for example), or both. Here we consider a methodologicalprocedure to study these differences applying it for 6 days Sinop data. This procedure isbased on three main analyses of the Sinop tower data that basically is constituted bymethodological approaches employed by other LBA research groups in analyzing theirdata. The three analyses are the following: 1) The application of an “u* filter” on thedata in order to find some regularity between the carbon and energy balance closure andthe level of turbulence of the air and wind velocity; 2) the recalculation, from the rawdata available when all equipment was running well, the micrometeorological variablesby employing a 800 s running mean, which is a value normally used by other eddy fluxmeasurement groups; and 3) the application of a Fourier analysis of the data in order toknow the diurnal and nocturnal low and high frequency of the variability of the data.The application of the three analyses possibly should improve the knowledge of theresearchers of the LBA program on some open questions involved in the theoretical andexperimental procedures employed in the towers.