Trace gas exchanges and convective transports over the Amazonian rain forest

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Abstract
The NASA Amazon Boundary Layer Experiment (ABLE 2A) based in Manaus, Brazil, in July and August, 1985, is used to examine meteorological processes responsible for the vertical and horizontal transport of biogenic and anthropogenic trace gases generated over the Amazon basin. Direct sampling of the surrounding environment of deep convective clouds shows marked changes in the vertical distribution of the lower and midtroposphere concentration of O3 and such surface‐derived species as CO, CO2, and NO. Thermodynamic observations, together with two‐dimensional cloud model simulations, confirm vertical transports within the convection and provide a basis to estimate the magnitude and efficiency of cloud upward and downward exchanges. A distinction is drawn between local changes due to convective updrafts and downdrafts and convective overturning as a net result of the storm processes. Marked variability is seen in trace gas concentrations along horizontal flight paths in the vicinity of the convection. Interpretation of simultaneously measured thermodynamic quantities and trace gas concentrations provide the information to infer the presence and direction of atmospheric transports and/or the presence of anthropogenic influences. The level of convective activity and the closely coupled Hadley and Walker circulations over the Amazon basin and its associated trace chemistry suggest the importance of this region to the global atmosphere.