Since December 2000, vertical profiles of CO2 have been measured above central Amazônia, over Tapajós National Forest (02º51'S; 54º57'W), and since 2004 over Cuieiras Biological Reserve (02º36'S, 60º12'W). Samples are collected aboard light aircraft between the surface and 4 km using the NOAA/CMDL semi-automatic portable flask package (PFP).
We have compared our vertical profiles to the NOAA/CMDL background site Ascension Island (ASC) located in the Atlantic Ocean (7 56'S, 14 22'W). Comparing the Dry Season of 2004 with the Wet Seasons of 2004 and 2005, in the Pará State, after subtraction of global influence, through the subtraction of the CO2 concentration of Ascension, obtained in the average 2 ppm more concentrations in the Wet season. CO2 profiles at this site, showed both lower and higher concentrations below boundary layer than above, indicating CO2 sinks and sources, respectively, but in the average is more sources in the wet season.
In the Amazon State, the wet season of 2005, after subtraction, show 10 ppm higher concentration below PBL than above, indicating source behavior. During the Dry season, the average concentration was 7 ppm higher above PBL than below, showing sink behavior.
Comparing both states during wet season of 2005, it was observed 2 ppm higher concentration above and 5 ppm below PBL in Amazonas state, in the average. General, we observed higher CO2 concentration in the Amazônia comparison with Ascension, showing contribution of continent emissions.