Abstract ID: 536

Seven Years of Regional CO2 Fluxes for Eastern Amazonia Derived Aircraft Vertical Profiles

Our project was designed to help determine regional-scale (~106 km2) fluxes of radioactively important trace gases. We have determined regional scale CO2 fluxes using atmospheric measurements from aircraft vertical profiles over Floresta Nacional do Tapajos (SAN - 02º51'S; 54º57'W). SAN profiles started December 2000 running until 2008. Samples are collected aboard light aircraft between the surface and 4 -5 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 subtracted with 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 the 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, averaged -0.03 ± 1.5 g C.m-2.day-1 for the wet season and 0.3 ± 0.9 g C.m-2.day-1 for the dry season. The variability at each site is high, most likely reflecting a variety of biological and anthropogenic processes. Regional-scale CO2 fluxes have been corrected removing the influence of biomass burning; using measurements of CO, showing the biological absorption during dry season of -0.04 ± 1.2 g C.m-2.day-1. This approach greatly reduces dry season CO2 emissions and possibly indicates a regional dry season sink of CO2.

Session:  Carbon - Scaling carbon fluxes to the region from measurements in plots, towers, and aircraft.

Presentation Type:  Oral