| NSF Org: |
OCE Division Of Ocean Sciences |
| Recipient: |
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| Initial Amendment Date: | August 23, 2018 |
| Latest Amendment Date: | January 8, 2024 |
| Award Number: | 1756789 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Baris Uz
bmuz@nsf.gov (703)292-4557 OCE Division Of Ocean Sciences GEO Directorate for Geosciences |
| Start Date: | September 1, 2018 |
| End Date: | March 31, 2024 (Estimated) |
| Total Intended Award Amount: | $815,815.00 |
| Total Awarded Amount to Date: | $823,891.00 |
| Funds Obligated to Date: |
FY 2019 = $8,076.00 |
| History of Investigator: |
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| Recipient Sponsored Research Office: |
438 WHITNEY RD EXTENSION UNIT 1133 STORRS CT US 06269-9018 (860)486-3622 |
| Sponsor Congressional District: |
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| Primary Place of Performance: |
1080 Shennecossett Road Groton CT US 06340-6048 |
| Primary Place of
Performance Congressional District: |
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| Unique Entity Identifier (UEI): |
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| Parent UEI: |
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| NSF Program(s): | PHYSICAL OCEANOGRAPHY |
| Primary Program Source: |
01001920DB NSF RESEARCH & RELATED ACTIVIT |
| Program Reference Code(s): |
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| Program Element Code(s): |
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| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.050 |
ABSTRACT
Understanding of air-sea boundary layer processes requires a quantitative description of mixing and transport in the ocean. The development and improvement of ocean models rely on results from comprehensive observation programs that capture mid- to small-scale turbulence which is associated with energy transfer from the atmosphere to the ocean. In this project, the role of surface gravity waves in energy transfer is studied by linking the atmosphere and ocean through a unique set of turbulence measurements. These are carried out simultaneously both on the air and water sides. To elucidate air-sea wave driven turbulence, the research teams will measure the vertical structure of the turbulence kinetic energy (TKE) dissipation rate across the air-sea interface from the Air Sea Interaction Tower at Martha's Vineyard Coastal Observatory. The proposed measurements of turbulence will enhance the understanding of coupled boundary layer dynamics and will improve existing and future air-sea interaction parameterizations. The field campaign will also create a data set for the community that we will be shared through an open-access data system. This will accelerate the development of high-resolution wave coupled ocean numerical models and improve both weather and ocean conditions forecasts. Outreach through education is also a focus of this program. In addition to the support and training of a graduate student and a post-doctoral researcher, undergraduate research experiences (REU) will be provided through an existing NSF-REU program (URI) and new collaborations with local schools to expose high school students to earth sciences (UConn).
This study focuses on the energy transfer from the atmosphere to the ocean and how this occurs across the air-sea interface. Indirect and direct observations of the energy flux divergence (wave-induced transport) on the atmospheric side will be used to constrain the magnitude of the air-sea TKE transfer rate and to provide an upper bound to the TKE injection by wave breaking (i.e. the breaker work). Direct estimates of active breaking and the resulting foam on the ocean surface will be used to provide complementary estimates of the subsurface TKE dissipation rate. On the ocean side, measurements of TKE dissipation rate and the TKE production and transport terms throughout the water column will be made using several complementary techniques. Using these measurements, the researchers will explore the expected TKE dissipation rate deficit/surplus at the interface relative to a rigid wall and assess the role of surface gravity waves in the deviations. Furthermore, an attempt will be made to elucidate and differentiate the effects of wave breaking and Langmuir Circulation driven turbulence and define characteristic turbulent scales to improve present and future mixing parameterizations in the upper ocean. On the atmospheric side, deviations from the law-of-the-wall are expected to be correlated to the energy flux divergence, which arises from wave motion creating an energy flux into the wave field. This study will characterize the wave signature on the air velocities and pressure on the atmospheric side, further elucidating the physics of the energy exchange.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
How the surface ocean and the lower atmosphere exchange energy and momentum are critical to the prediction of climate and weather models. We have made measurements with which to evaluate theoretical prediction of how waves and turbulence control this exchange in a site in the northwest Atlantic. We find that the rate of dissipation of turbulence near the surface of the ocean (top 5m) is one hundred time higher than expected from simple theory but tends to agreement at greater depth. Our measurements spanned a wide range of sea-states, and we find that the thickness of the layer of enhanced dissipation is approximately 5 times the significant wave height. On the atmospheric side of the boundary the dissipation rate of turbulent energy is less than expected. Measurements of wave and wind character suggest that the breaking of surface waves contributes to the enhanced turbulence in in the ocean. We developed empirical relationship quantifying these findings. The depth, z, strucure of the disspiation rate, e, behaves as eH/F ~ (z/H)b where H is the significant wave height, b=-2.5, and F ~ u*3, where u* is the wind stress velocity.
We have created a web site (http://merlin.dms.uconn.edu/bulk_data) to host teh data we acquired so that others may build on our work. We recently published a journal article (Cifuentes-Lorenzen, A. C. Zappa, J. Edson, J. O’Donnell, and D. Ullman (2023). Exploring the role of wave-driven turbulence at the air-sea interface through measurements of TKE dissipation rates across the air-sea interface. J. Geophys. Res.(Oceans) 129, e2023JC020308. https://doi.org/10.1029/2023JC020308) nad have two more in draft form.
The project developed new scientists, Dr. Youngmi Shin, a Post-Doc at UConn; Lindsay Hogan, a graduate student at Columbia University; and through an REU supplement, 2 undergraduate students at CSU Maritime Academy. One student participated in the deployment and one student worked on data processing.
Last Modified: 09/03/2024
Modified by: James O'donnell
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