Thermal enhancement of gas transfer velocity of CO2 in an Amazon floodplain lake revealed by eddy covariance measurements
|Author(s)||Polsenaere Pierre1, Deborde Jonathan1, Detandt Guillaume1, Vidal Luciana O.2, Perez Marcela A. P.3, Marieu Vincent1, Abril Gwenael1, 4|
|Affiliation(s)||1 : Univ Bordeaux, Lab Environm & Paleoenvironm Ocean & Continentaux, CNRS UMR 5805, F-33405 Talence, France.
2 : Univ Fed Juiz de Fora, Aquat Ecol Lab, Juiz De Fora, MG, Brazil.
3 : Univ Fed Fluminense, Programa Geoquim Ambiental, Rio De Janeiro, Brazil.
4 : Inst Rech Dev, Lab Geosci & Environm Toulouse, Toulouse, France.
|Source||Geophysical Research Letters (0094-8276) (Amer Geophysical Union), 2013-05 , Vol. 40 , N. 9 , P. 1734-1740|
|WOS© Times Cited||27|
In November 2011, the partial pressures of carbon dioxide (pCO(2)) in water and air in a floodplain lake of the Amazon River in Brazil were 800 +/- 75 and 387 +/- 8 ppmv, respectively. Turbulent CO2 fluxes from the lake measured with eddy covariance ranged from 0.05 to 2.2 mmol m(-2) s(-1). The corresponding gas transfer velocities k(600) ranged from 1.3 to 31.6 cm h(-1), averaging 12.2 +/- 6.7 cm h(-1). At moderate to high wind speed, k(600) increased with wind speed, with values above parameterizations for other lake ecosystems. During the prevailing tropical low wind speed (below 2.7 m s(-1)) and high insolation conditions, unexpected high k(600) values (up to 20 cm h(-1)) were obtained and correlated with latent heat and sensible heat fluxes. In Amazonian open lakes, owing to long quiescent periods of low wind speed but extremely high daytime insolation and heat fluxes, thermal enhancement makes time-integrated gas transfer velocities four to five times higher than those computed from classic wind parameterization.