The Role of Argus in the NCEX Field Experiment Rob Holman SECNAV/CNO Chair in Oceanography

Argus I

Argus II

Argus III

Pixel Instrument Coverage (early test example)

shoreline NCEX Tessellation Array Resolution limited (5 m) 1842 pixels tile

Tessellation Array Locations

Example Directional Spectra

Tessellation Arrays Produce wave directional “spectrum” at any location Extract simple statistics (peak direction?) Use same lag array for depth estimation

NCEX Array, 09/03

NCEX Array, 09/03 (blow-up) Runup “Old” Bathy Line Vbar Tess (alpha and bathy

Longshore Currents (Chris Chickadel)

Orientation for Next Slide

10/31/03, 0700 Variance Image Happy Halloween Rip current

Radiation Stress Gradients where: S xy = Radiation Stress = mean dissipation due to wave breaking  = local incident wave angle c = celerity Components in both the longshore and cross-shore directions Concentration on diagonal component S xy Optical techniques necessary for all parameters to allow remote sensing Work of Jason Killian

Fusion with Numerical Models Based on: Wave direction Surf zone width

California Fires, 10/28/03 Mid-afternoon view Southern California

Estimation of Swash Velocities Runup transect from NCEX exp’t, 2004

Two-minute Time Stack NCEX stack, 2003

Band-pass Isolation of Foam

Consecutive Intensity Transects

Analysis Band-pass to isolate foam Hilbert transform to extract phase and wavenumber U = d(phase)/dt * 1/k

Example Sub-stack Results

Example Sub-stack

Example Sub-stack Overlay

Two-minute Sub-stack Example 17 minute run takes 9 seconds

Application of Hilbert Approach to Longshore Currents? (and rips?) Longshore velocity = = 0.60 m/ sec yy tt Duck, NC 0 40 Time (sec)  t = 18.7 s  y =11.3 m Longshore Distance (m)

Questions? Dr. Aarninkhof Distinguished Argus Scientist Costas Synolakis Oregon State University Wave Tank, 2003