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Buoyancy flux, turbulence, and the gas transfer coefficient in a stratified lake
Author(s) -
MacIntyre Sally,
Jonsson Anders,
Jansson Mats,
Aberg Jan,
Turney Damon E.,
Miller Scott D.
Publication year - 2010
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2010gl044164
Subject(s) - eddy covariance , buoyancy , turbulence , flux (metallurgy) , environmental science , atmospheric sciences , wind speed , meteorology , climatology , mechanics , geology , physics , materials science , ecosystem , ecology , metallurgy , biology
Gas fluxes from lakes and other stratified water bodies, computed using conservative values of the gas transfer coefficient k 600 , have been shown to be a significant component of the carbon cycle. We present a mechanistic analysis of the dominant physical processes modifying k 600 in a stratified lake and resulting new models of k 600 whose use will enable improved computation of carbon fluxes. Using eddy covariance results, we demonstrate that i) higher values of k 600 occur during low to moderate winds with surface cooling than with surface heating; ii) under overnight low wind conditions k 600 depends on buoyancy flux β rather than wind speed; iii) the meteorological conditions at the time of measurement and the inertia within the lake determine k 600 ; and iv) eddy covariance estimates of k 600 compare well with predictions of k 600 using a surface renewal model based on wind speed and β .