SASCWATCH: Study on Air-Sea Coupling with WAves, Turbulence, and Clouds at High winds
Sponsor
Office of Naval Research MURI N00014-24-1-2554
Project duration
2024 - 2029
Summary
The exchange of momentum, heat, and moisture between the ocean and atmosphere plays a central role in the presence, timing, location, and severity of extreme weather events including tropical cyclones (TCs). Traditionally, the atmosphere-wave-ocean intersection has been frequently treated as three separate, nearly independent problems despite a growing recognition that these are highly coupled processes. What results from this, however, are incomplete descriptions of the principle modulators of momentum, heat, and moisture fluxes in high winds, including the role of waves, currents, and atmospheric turbulence.
The main objective of the SASCWATCH project, therefore, is to advance understanding of high-wind fluxes by using a coordinated combination of in situ observations, mesoscale coupled modeling, and high-resolution turbulence simulations. The governing science questions are:
- Surface waves in extreme environments: what are their properties, and how do they modulate air-sea transfer?
- With the emergence of numerical and observational techniques that can now resolve turbulent processes in the hurricane boundary layer (HBL), can we finally constrain air-sea fluxes and their behavior at high winds?
- What is the nature of air-sea fluxes through the transition from low-wind conditions to TC environments, and how quickly do certain physical processes give way to others as the winds approach tropical storm or TC levels?
The observational work centers on co-located measurements of ocean, wave, and atmospheric turbulence properties simultaneously. Ocean assets capable of measuring SST, OHC, directional wave spectra, and currents will be pre-deployed via the USAFR 53rd Weather Reconnaissance Squadron. Subsequent coordination with the NOAA Hurricane Hunters will yield flyovers with multiple instrumentation, including remote sensing and small uncrewed aerial systems (sUAS) capable of measuring turbulence and fluxes at low, sustained altitudes.
The SKRIPS coupled mesoscale model will explore the ocean-wave-atmosphere coupling, emphasizing verification and validation of waves, currents, and flux parameterizations with observed values. Physics-resolving large eddy simulations will also be used to explore the process-level influence of waves and wave-induced turbulence and sea spray, and also provide context for interpreting fluxes estimated from sUAS and flux-profile methods.
Outcomes include: improved parameterizations of surface fluxes, particularly in regards to underlying wave properties; spatial mappings of surface wave/current/wind properties in storms, to clarify the role of storm-relative dependence of fluxes; advances in theoretical understanding which enables an improved interpretation of past observations.
2025 Hurricane Erin Deployment
Video from LtCol Mark Withee and the 53rd "Hurricane Hunter" Weather Reconnaissance Squadron showing the buoy array deployment ahead of Hurricane Erin, August 18, 2025
Science Plan
The full science plan can be found here
PIs
- David Richter, University of Notre Dame
- Michael Bell, Colorado State University
- Bia Villas Bôas, Colorado School of Mines
- Beth Sanabia, University of Washington
- Steve Jayne, Woods Hole Oceanographic Institute
- Henry Potter, Texas A&M University
Collaborators
- Johna Rudzin, Mississippi State University
- Jun Zhang, NOAA
- Joe Cione, NOAA
- Jason Dunion, NOAA
- Greg Foltz, NOAA
- Dongxiao Zhang, NOAA
- Lev Looney, NOAA
- Heather Holbach, NOAA
- Josh Wadler, Embry-Riddle Aeronautical University
- Peter Sullivan, National Center for Atmospheric Research
- Martha Schönau, UCSD/Scripps Institute of Oceanography
- Jim Doyle, NRL Monterey
- Dan Stern, NRL Monterey
- Pete Finocchio, NRL Monterey
- Lynn (Nick) Shay, University of Miami
- Benjamin Jaimes de la Cruz, University of Miami
- Milan Curcic, University of Miami
- Brian Haus, University of Miami
ONR Program Management
- Josh Cossuth, Code 322: Marine Meteorology and Space Weather
- Dan Eleuterio, Code 322: Marine Meteorology and Space Weather