Rain-induced turbulence and air-sea gas transfer

View/ Open
Date
2009-07-09Author
Zappa, Christopher J.
Concept link
Ho, David T.
Concept link
McGillis, Wade R.
Concept link
Banner, Michael L.
Concept link
Dacey, John W. H.
Concept link
Bliven, Larry F.
Concept link
Ma, Barry
Concept link
Nystuen, Jeffrey A.
Concept link
Metadata
Show full item recordCitable URI
https://hdl.handle.net/1912/3815As published
https://doi.org/10.1029/2008JC005008DOI
10.1029/2008JC005008Keyword
Turbulence; Rain; Gas transferAbstract
Results from a rain and gas exchange experiment (Bio2 RainX III) at the Biosphere 2 Center demonstrate that turbulence controls the enhancement of the air-sea gas transfer rate (or velocity) k during rainfall, even though profiles of the turbulent dissipation rate ɛ are strongly influenced by near-surface stratification. The gas transfer rate scales with ɛ inline equation for a range of rain rates with broad drop size distributions. The hydrodynamic measurements elucidate the mechanisms responsible for the rain-enhanced k results using SF6 tracer evasion and active controlled flux technique. High-resolution k and turbulence results highlight the causal relationship between rainfall, turbulence, stratification, and air-sea gas exchange. Profiles of ɛ beneath the air-sea interface during rainfall, measured for the first time during a gas exchange experiment, yielded discrete values as high as 10−2 W kg−1. Stratification modifies and traps the turbulence near the surface, affecting the enhancement of the transfer velocity and also diminishing the vertical mixing of mass transported to the air-water interface. Although the kinetic energy flux is an integral measure of the turbulent input to the system during rain events, ɛ is the most robust response to all the modifications and transformations to the turbulent state that follows. The Craig-Banner turbulence model, modified for rain instead of breaking wave turbulence, successfully predicts the near-surface dissipation profile at the onset of the rain event before stratification plays a dominant role. This result is important for predictive modeling of k as it allows inferring the surface value of ɛ fundamental to gas transfer.
Description
Author Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 114 (2009): C07009, doi:10.1029/2008JC005008.
Collections
Suggested Citation
Journal of Geophysical Research 114 (2009): C07009Related items
Showing items related by title, author, creator and subject.
-
Observations of the transfer of energy and momentum to the oceanic surface boundary layer beneath breaking waves
Scully, Malcolm E.; Trowbridge, John H.; Fisher, Alexander W. (American Meteorological Society, 2016-06-02)Measurements just beneath the ocean surface demonstrate that the primary mechanism by which energy from breaking waves is transmitted into the water column is through the work done by the covariance of turbulent pressure ... -
Investigations of scalar transfer coefficients in fog during the Coupled Boundary Layers and Air Sea Transfer Experiment : a case study
Crofoot, Robert Farrington (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2004-09)The uncertainty in the determination of the momentum and scalar fluxes remains one of the main obstacles to accurate numerical forecasts in low to moderate wind conditions. For example, latent heat fluxes computed from ... -
Entrainment and mixed layer dynamics of a surface-stress-driven stratiified fluid
Manucharyan, Georgy E.; Caulfield, C. P. (2014-12)We consider experimentally an initially quiescent and linearly stratified fluid with buoyancy frequency NQ in a cylinder subject to surface-stress forcing from a disc of radius R spinning at a constant angular velocity Ω. ...