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TG-06 Abstract

Vertical Profiles of Carbon Dioxide and Other Trace Gas Species Over the Amazon Basin Using Small Aircraft

Paulo Artaxo — USP - Universidade de Sao Paulo (SA-PI)
Pieter P. Tans — NOAA/ESRL (US-PI)


We will carry out, at two sites and during the full multi-year period of LBA, weekly

measurements of the vertical profiles of several trace gas species and isotope ratios. We

will measure the mixing ratios of CO2, CO, CH4, N2O, H2

and SF6, and the 13C/12C and 18O/16O

isotopic ratios in CO2, in 20 flask samples collected automatically during each

flight up to an altitude of 3-5 km or more, depending on the altitude ceiling of available

local aircraft for hire. As they are available, we will use NASA, INPE or other research

aircraft to obtain samples at higher altitudes. Flask samples will be collected over the

ocean NE of Belem and over a forest area in the central Amazon basin in order to quantify

the change in trace gas mixing ratios and isotopic composition during the transit of air

across the basin. The central basin site will be coordinated with one of the flux tower

clusters. Other areas will be sampled on a campaign basis, and coordinated with other LBA

investigations, primarily to examine the isotopic signature of CO2 exchange in

other ecosystem types. The flasks will be analyzed in our laboratory in Boulder using

existing equipment, and all species mixing ratios and isotopic ratios will be firmly tied

to internationally accepted calibration scales. The observations will constitute the first

multi-year time series of CO2, CH4 and N2O mixing ratios

and CO2 isotopic composition over the Amazon region. Measurements of SF6

will give a sensitive indicator for penetration of northern hemisphere air into the study

area. The data will provide an important constraint for regional and global models of

these trace gases, and an independent estimate of regional exchange for validation of

scaling of observations from the flux towers to the whole LBA study area. In addition, the

payload requirements for our equipment are modest, approximately 60 kg, and our aircraft

flights could be a useful resource for other investigators in LBA.

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