Author(s):
MacIntyre, Sally ; Fernandes Amaral, Joao H. ; Barbosa, Pedro Maia ; Cortés, Alicia ; Forsberg, Bruce Rider ; Melack, John M.
Date: 2020
Origin: Oasisbr
Subject(s): Air; Budget Control; Buoyancy; Floods; Forestry; Gases; Heat Flux; Kinetic Energy; Kinetics; Turbulent Flow; Acoustic Doppler Velocimeter; Buoyancy Fluxes; Flood-plains; Gas Flux; Surface Energy Budget; Tropical Lakes; Turbulence Productions; Turbulent Kinetic Energy; Turbulence; Buoyancy; Energy Budget; Energy Dissipation; Floodplain; Gas Flow; Heat Flux; Kinetic Energy; Meteorology; Open Water; Energy Surface; Tropical Environment; Turbulence; Water Column; Amazon Basin
Description
Seasonally flooded forests along tropical rivers cover extensive areas, yet the processes driving air-water exchanges of radiatively active gases are uncertain. To quantify the controls on gas transfer velocities, we combined measurements of water-column temperature, meteorology in the forest and adjacent open water, turbulence with an acoustic Doppler velocimeter, gas concentrations, and fluxes with floating chambers. Under cooling, measured turbulence, quantified as the rate of dissipation of turbulent kinetic energy (ε), was similar to buoyancy flux computed from the surface energy budget, indicating convection dominated turbulence production. Under heating, turbulence was suppressed unless winds in the adjacent open water exceeded 1 m/s. Gas transfer velocities obtained from chamber measurements ranged from 1 to 5 cm/hr and were similar to or slightly less than predicted using a turbulence-based surface renewal model computed with measured ε and ε predicted from wind and cooling. ©2019. The Authors.
