Interaction of the Marine Atmosphere and Ocean Waves Grant Number: N00014-07-1-0195 Carl A. Friehe

1. Interaction of the Marine Atmosphere and Ocean Waves Grant Number: N00014-07-1-0195 Carl A. Friehe Departments of Mechanical Engineering and Earth System Science University of California, Irvine Irvine, CA 92679-3975 cfriehe@uci.edu 949-824-6159 (O);949-302-5308(M);949-824-8585(Fax) Objective: To elucidate wind-wave interactions from measurements of the wind and wind stress from centimeters to 100’s of meters above ocean waves. Methods: A 15-m tall mast will be used on FLIP’s port boom instrumented with wind sensors and sonic anemometers. A wind LIDAR will be installed on FLIP’s upper deck to profile the wind vector from 20m to 300m. A miniature water-proof LDA will be suspended from FLIP’s boom to measure the 3-D wind near and in the waves. Collaborators: Tihomir Hristov, Ken Melville, Qing Wang, Mike Banner Outcomes: Effects of waves on wind and vice-versa; improved drag coefficient parameterization; coupling to the Marine Boundary Layer; detection of possible flow separation in wave troughs. MBL HiRes

2. Atmospheric Surface Layer Measurements • Conventional: The port-side mast will be instrumented for wind profile and stress divergence measurements from ~3 to ~20m above the sea. Motion of the mast will be measured with a GPS/INU device at the hinge point. Wind: 10 cup or 2-D sonics; Stress: 5 3-D sonics. Static pressure: Paroscientific (Hristov). Temperature profiles will be attempted with precision thermistors to resolve previous results. The humidity profile is probably not attainable with present sensors. • Waves: Coordinate with Melville, Terrill. Redundant systems of wires, sonic, radar etc., from the booms. Coordinate with images of breaking. • SST: IR sensor and near surface thermistor on float.

3. Connection to the Marine Boundary Layer • Marine Boundary Layer: via a DURIP, an up-ward pointing wind Lidar will be placed on the upper deck or platform of FLIP to return the 2-D wind profile from ~20m to ~300m, depending on the concentration of aerosol scatterers. or ~ 1m x 1m x 1m ~ 1.5 m high

4. Probe A Probe B Probe C Connection to the Surface Wave Field • Via a DURIP, a small waterproof Laser Doppler Anemometer (LDA) will be suspended below the port boom of FLIP to measure the 3-D velocity field near and in the wave field.

5. 3m WAVE FOLLOWER for NEAR-SURFACE ABL PRESSURE & WIND MEASUREMENTS Michael Banner et al. pressure anemometer ( self purging)

6. Wind Lidar Mast Follower LDA

7. Expected Results • Wind profile – “Law of the Wall” semi-log profile or not? • Stress Divergence – MBL showed it to be non-zero under high winds and waves • Temperature profile – Kansas or not? • Connection of the surface layer fields to the rest of the MBL. • Near-wave wind field: Is there flow separation in the trough? • Banner: the WF measurements will provide the near-surface pressure and turbulence, and their two-point vertical gradient, over the waves within its tracking bandwidth, thereby filling the gap in the kinematic and dynamic wind data in the zone between the fixed anemometer tower and the sea surface

8. FLIP Component of Experiment • FLIP: 11 science party + 5 crew = 16 maximum • Location: Off Pt. Conception, Strong down-coast winds (Dorman and Winant). • One month on station, 3-point mooring, keel into wind. • PIs: • Melville +? • Terrill +? • Hristov +? • Jessup +? • Banner +? • Friehe +? • Test cruise? • Schedule: Test off Pt. Loma 2008; Expt April-June 2009

9. MBL Experiment: Miller, Hristov, Friehe Stress Divergence at Higher Winds and Waves

10. FLIP RED Experiment Scalar Flux-Profile M-O Parameterizations Red: Temperature, Green: Humidity Black: Temperature over Land