CO2 Fluxes Derived for Column Integration Technique Using Aircraft Profiles in Amazônia
Gatti, IPEN/LQA, email@example.com
D'Amelio, IPEN/LQA, firstname.lastname@example.org
Miller, NOAA/ESRL, John.B.Miller@noaa.gov
Vaz, IPEN/LQA, email@example.com
Crotwell, NOAA/ESRL, firstname.lastname@example.org
Tans, NOAA/ESRL, Pieter.Tans@noaa.gov
Wofsy, Harvard University, email@example.com
We determine regional scale CO2 fluxes using atmospheric measurements from aircraft profiles over Floresta Nacional do Tapajos (SAN - 02º51'S; 54º57'W, over tower 67km) and Reserva Biologica de Cuieiras (MAN - 02º36'S, 60º12'W, over tower K34). SAN profiles started December 2000 and MAN started December 2004, both running until 2007. Samples are collected aboard light aircraft between the surface and 4 km using the NOAA/ESRL semi-automatic portable flask package (PFP), with 17 flasks samples.
We use a column integration technique to determine the CO2 flux for each vertical profile, where the measured CO2 profile is differenced from the CO2 background. The CO2 background was determined using co-measured SF6 as a transport tracer. Two NOAA/ESRL background sites, Ascension Island (ASC) located in the Atlantic Ocean (8'S, 14'W) and Barbados (RPB) located in the Atlantic Ocean (12'N, 59'W) were used to calculate the fractions of air arriving at the sites studied. Back trajectories from HYSPLIT model were calculated for every profile every 500m of altitude to determine the time the air mass took to travel between the coast and the sites.
The observed flux, that reflects the flux between the coast and measurement sites, showed for SAN an average of -0.4 ± 1.2 gC/m².day for the wet season and 0.8 ± 1.3 gC/m².day for the dry season. At MAN the average for the wet season was 0.6 ± 1.4 gC/m².day and for the dry season, 0.8 ± 2.3 gC/m².day. The variability at each site is high, most likely reflecting a variety of biological and anthropogenic processes.
We will also present regional-scale CO2 fluxes that have been corrected for the influence of biomass burning; using measurements of CO. This approach greatly reduces dry season CO2 emissions and possibly indicates a regional dry season sink of CO2, consistent with the local-scale eddy covariance results of Saleska et al.2003.