Open AccessMicroscale wave breaking and air‐water gas transfer
Author(s) -
Zappa C. J.,
Asher W. E.,
Jessup A. T.
Publication year - 2001
Publication title -
journal of geophysical research: oceans
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2000jc000262
Subject(s) - microscale chemistry , breaking wave , surface wave , mechanics , physics , wind wave , meteorology , atmospheric sciences , wave propagation , thermodynamics , optics , mathematics education , mathematics
Laboratory results showing that the air‐water gas transfer velocity k is correlated with mean square wave slope have been cited as evidence that a wave‐related mechanism regulates k at low to moderate wind speeds [ Jähne et al. , 1987; Bock et al. , 1999]. Csanady [1990] has modeled the effect of microscale wave breaking on air‐water gas transfer with the result that k is proportional to the fractional surface area covered by surface renewal generated during the breaking process. In this report we investigate the role of microscale wave breaking in gas transfer by determining the correlation between k and A B , the fractional area coverage of microscale breaking waves. Simultaneous, colocated infrared (IR) and wave slope imagery is used to verify that A B detected using IR techniques corresponds to the fraction of surface area covered by surface renewal in the wakes of microscale breaking waves. Using measurements of k and A B made at the University of Washington wind‐wave tank at wind speeds from 4.6 to 10.7 m s −1 , we show that k is linearly correlated with A B , regardless of the presence of surfactants. This result is consistent with Csanady 's [1990] model and implies that microscale wave breaking is likely a fundamental physical mechanism contributing to gas transfer.