CD-14 Abstract

CO2 Budget Regional Airborne Study (COBRA)-Brazil

Steven C. Wofsy -- Harvard University
Maria Assuncao Faus Silva Dias -- Universidade de São Paulo (USP)

Motivation. The Amazon Basin is a key component of the global carbon
cycle, containing one-half of the world's undisturbed tropical forest
and accounting for ~10% of global terrestrial net primary
productivity.  Current estimates of carbon fluxes in Amazonia at the
regional and Basin scales are subject to large uncertainties that
propagate into the global carbon budget.  Regional and Basin scale
carbon exchanges fall into the "missing scale" in carbon cycle science
due to a) dearth of CO2 observations over the continent to constrain
inverse models and b) lack of independently validated methodologies to
scale up local measurements. 

The proposed study will conduct in-situ airborne measurements
of CO2 and CO in the lower- and mid-troposphere over the Amazon Basin.
The proposed strategy for observations and analysis will provide
direct estimates of carbon fluxes at the missing regional and Basin
scales.  We plan to conduct this study during both wet and dry seasons
to capture the seasonal variability and to complement LBA airborne
remote-sensing missions. 


directly quantify regional and Basin-scale fluxes in Amaztnia using
airborne measurements of CO2 and other tracers in and above the
planetary boundary layer (PBL);


The proposed strategy has been successfully implemented in a
pilot study (COBRA 2000) conducted over North America and consists of
the following complementary approaches:


Direct estimates of CO2 fluxes at regional and Basin scales to test
ideas about net sources or sinks of CO2 in Amazonia, and against which
methods for scaling up local measurements can be evaluated, including:

Vertical and horizontal distributions of CO2 in the troposphere over
Amazonia and between the American Midwest and Brazil that: