The Prediction of Wind-Driven Coastal Circulation

PIs: John Allen and Jack Barth, OSU

Academic Partners:

Government Partners:

Industrial Partners:

COAS, OSU, Corvallis, OR (Allen, Barth, Boyd, Caldwell, Egbert, Huyer, Kosro, Levine, Miller, Moum, Samelson, Skyllingstad)

NOAA, NMFS, Newport, OR (Peterson)NOAA, ETL, Boulder, CO (Harlan, Wilczak)

CODAR Ocean Sensors, Los Altos, CA (Barrick, Lipa)Ocean Imaging, Solana Beach, CA (Svejkovsky)

OSU NOPP

Goal: Develop nowcast and forecast systems for wind-driven coastal ocean flow fields (alongshore coastal jets, upwelling and downwelling fronts, eddies, surface and bottom boundary layers)

Approach:•High-resolution coastal ocean and coastalatmospheric models

•Data assimilation

and bio-optics

•land-based coastal radar•moorings•turbulence profiling•atmospheric profiling•SeaSoar and MiniBAT hydrography

•Observational program

Barth, Kosro•wind-driven upwelling separated by wind relaxation events•upwelling over the shelf, broadening over the submarine banks•subsurface thermal features influenced by submarine bank topography

OSU-NOPP: Ocean Observations

•Land-based coastal radar (CODAR)surface velocities

•Alongshore jet following bottomtopography and intensified over thesubmarine banks

Kosro, Harlan

OSU-NOPP: Ocean Observations

OSU-NOPP: Atmospheric Model

Samelson, Skyllingstad, Wilczak

•mean and variable alongshore wind stress increases by a factor of 3-4 from north to south•intensification near Cape Blanco at 43N

OSU-NOPP: Atmospheric Model

Samelson, Skyllingstad, Wilczak

•atmospheric model provides useful estimates of

Model (solid) vs. buoy (dashed) wind stressModel minus buoy surface air temperature (solid) vs. alongshore wind stress (dashed)

wind stress•ocean upwelling evidently modifies coastal surface

air temperature by 1-5 degrees C over time scalesof 1-2 days

(Model SST is from large-scale analysis that does not resolve upwelling response.)

OSU-NOPP: Coastal Ocean Model

With spatially uniform winds With spatially varying winds

•Results with spatially varying wind stress forcing are qualitatively and quantitatively closer to observations

Modeled (solid) vs. observed (dashed) alongshelf currents at 20m

(top) with spatially uniform winds(bottom) with spatially variable winds

Allen, Gan(Moored observations: Levine, Kosro, Boyd)

OSU-NOPP: Data Assimilating Coastal Ocean Model

Oke, Allen, Miller, Egbert, Kosro

wind

observedvelocity

withassimilation

modeled(no data)

•Land-based radar velocities assimilated into a primitive equation ocean circulation model•velocity correlations between observations and the data-assimilating model substantially improved

over a model with no assimilation

•Data-assimilating model surface temperature maps capture observed broadening of upwelling

region over Heceta Bank

1998