TY - JOUR
T1 - A Laboratory Investigation of Spume Generation in High Winds for Fresh and Seawater
AU - Mehta, S.
AU - Ortiz-Suslow, D. G.
AU - Smith, A. W.
AU - Haus, B. K.
N1 - Funding Information:
This work was funded by NSF through Grant 0933943. Additional support was provided through ONR phase‐resolved wave program under Grant N000141410644. We appreciate the efforts of Mike Rebozo and Dr. Neil Williams for the help with the data collection. We would also like to especially thank Dr. Andrew Margolin for his helpful discussions in conceptualizing the findings of this study. We must acknowledge the rigorous and careful review of an anonymous reviewer, whose prodigious efforts unquestionably improved the quality and communicability of this study. Data are archived at the University of Miami repository under the name Spray Concentration Measurements from ASIST for Freshwater and Seawater.
PY - 2019/11/16
Y1 - 2019/11/16
N2 - Given spume's role in mediating air-sea exchange at the base of tropical cyclones or other storm events, the focus of studies on spray dynamics has been within the marine environment. In contrast, spume production in nonseawater bodies has been underexplored and potential differences between sea and freshwater are neglected. The laboratory remains the primary means for directly observing spray processes near the surface because of the challenges to making robust field measurements. There is no standardization on the water type used for these experiments, and the effect this has on the generation process is unknown. This adds uncertainty in our ability to make physically realistic spume generation functions that are ultimately applied to the geophysical domain. We have conducted a laboratory experiment that aims to address this simple, yet overlooked, question of whether water type impacts the spume droplet concentration entrained in the air flow above actively breaking waves. We compared directly imaged concentrations for fresh and seawater droplets produced in 10-m equivalent winds from 36–54 m/s. Substantially higher concentrations of seawater spume were observed, as compared to freshwater across all particle sizes and wind speeds. The seawater particles' vertical distribution was concentrated near the surface, whereas the freshwater droplets were more uniformly distributed. Our statistical analysis of these findings suggests significant differences in the size- and height-dependent distributions response to increased wind forcing between fresh and seawater. These unexpected findings suggest an unanticipated role of the source water physiochemical properties on the spume generation mechanism.
AB - Given spume's role in mediating air-sea exchange at the base of tropical cyclones or other storm events, the focus of studies on spray dynamics has been within the marine environment. In contrast, spume production in nonseawater bodies has been underexplored and potential differences between sea and freshwater are neglected. The laboratory remains the primary means for directly observing spray processes near the surface because of the challenges to making robust field measurements. There is no standardization on the water type used for these experiments, and the effect this has on the generation process is unknown. This adds uncertainty in our ability to make physically realistic spume generation functions that are ultimately applied to the geophysical domain. We have conducted a laboratory experiment that aims to address this simple, yet overlooked, question of whether water type impacts the spume droplet concentration entrained in the air flow above actively breaking waves. We compared directly imaged concentrations for fresh and seawater droplets produced in 10-m equivalent winds from 36–54 m/s. Substantially higher concentrations of seawater spume were observed, as compared to freshwater across all particle sizes and wind speeds. The seawater particles' vertical distribution was concentrated near the surface, whereas the freshwater droplets were more uniformly distributed. Our statistical analysis of these findings suggests significant differences in the size- and height-dependent distributions response to increased wind forcing between fresh and seawater. These unexpected findings suggest an unanticipated role of the source water physiochemical properties on the spume generation mechanism.
KW - air-sea interaction
KW - freshwater versus seawater
KW - high winds
KW - laboratory experiments
KW - particle image velocimetry
KW - sea spray production
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U2 - 10.1029/2019JD030928
DO - 10.1029/2019JD030928
M3 - Article
AN - SCOPUS:85074857922
VL - 124
SP - 11297
EP - 11312
JO - Journal of Geophysical Research: Atmospheres
JF - Journal of Geophysical Research: Atmospheres
SN - 2169-897X
IS - 21
ER -