Title | Lake-size dependency of wind shear and convection as controls on gas exchange |
Publication Type | Journal Article |
Year of Publication | 2012 |
Authors | Read JS, Hamilton DP, Desai AR, Rose KC, MacIntyre S, Lenters JD, Smyth RL, Hanson PC, Cole JJ, Staehr PA, Rusak JA, Pierson DC, Brookes JD, Laas A, Wu CH |
Journal | Geophysical Research Letters |
Volume | 39 |
Date Published | 05/2012 |
Keywords | gas exchange, turbulence, wind shear |
Abstract | High-frequency physical observations from 40 temperate lakes were used to examine the relative contributions of wind shear (u*) and convection (w*) to turbulence in the surface mixed layer. Seasonal patterns of u* and w* were dissimilar; u* was often highest in the spring, while w* increased throughout the summer to a maximum in early fall. Convection was a larger mixed-layer turbulence source than wind shear (u*/w* < 0.75) for 18 of the 40 lakes, including all 11 lakes <10 ha. As a consequence, the relative contribution of convection to the gas transfer velocity (k, estimated by the surface renewal model) was greater for small lakes. The average k was 0.54 m day1 for lakes <10 ha. Because u* and w* differ in temporal pattern and magnitude across lakes, both convection and wind shear should be considered in future formulations of lake-air gas exchange, especially for small lakes. |
URL | http://www.agu.org/pubs/crossref/2012/2012GL051886.shtml |
DOI | 10.1029/2012GL051886 |
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