1 high resolution unstructured grid for wave forecasting at coastal areas 14th ems annual meeting...

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HIGH RESOLUTION UNSTRUCTURED GRID FOR WAVE FORECASTING AT COASTAL AREAS

14th EMS Annual Meeting & 10th European Conference on Applied Climatology. October 2014 | Prague, Czech Rep.

Ángel Martínez Ferrer, amartinezf@aemet.es Justo Conde Criado, jcondec@aemet.es Ernesto Barrera Rodríguez, jbarrera@aemet.es

SPANISH METEOROLOGICAL AGENCY. MARINE PROGRAM. MADRID

26/01/2008 AEMET, Agencia Estatal de Meteorología

High resolution unstructured grid for wave forecasting at coastal areas

SUMMARY

- State-of-the-art of wave models.

- Nesting scheme – from Ocean to Strait.

- Fractional steps.

- Network of forecasting modules.

- SWAN in the Strait.

- Unstructured grid for coastal areas.

- Buoy observations vs model forecasts.

3www.aemet.es 3

High resolution unstructured grid for wave forecasting at coastal areas

4www.aemet.es 4

Regional WW3 3-1.5’ and SWAN in the strait

High resolution unstructured grid for wave forecasting at coastal areas

Atlantic nesting: 24-12-6' --- regional

Regional nesting South + East: 3-1.5'---SWAN strait

area of study

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High resolution unstructured grid for wave forecasting at coastal areas

Flow unstabilities if Courant-Friedrichs-Levi condition is not met: Δt>Δx/c. Spatial propagation time step should be:

Δtp< Δx/cg =123766* Δx(º)*cos(latmax)*fmin

Iberia---- Δx=1’, latmax=37º, fmin=0.041Hz -> Δtp=80 s

… too much computing time!

Fractional steps philosophy:

WW3 alternates calculations among spatial and spectral propagations and source terms, so

Δtp ≤ 100 s

with higher time steps...

WHAT'S THE HIGHEST TIME STEP WITHOUT UNSTABILITY?

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High resolution unstructured grid for wave forecasting at coastal areas

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High resolution unstructured grid for wave forecasting at coastal areas

IT IS NECESSARY TO COMBINE DIFFERENT MEDIA

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High resolution unstructured grid for wave forecasting at coastal areas

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High resolution unstructured grid for wave forecasting at coastal areas

OBJECT OF STUDY- PASS BETWEEN ATLANTIC AND MEDITERRANEANSWAN AT x=3/8'

WINDS FROM HARMONIE AT 2.5 km (or less...)

Gibraltar strait: dense maritime trafic (W-E, and also N-S) with adverse meteorological conditions

Algeciras buoy

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High resolution unstructured grid for wave forecasting at coastal areas

EASTERLY EPISODE

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High resolution unstructured grid for wave forecasting at coastal areas

UNSTRUCTURED GRID AT THE STRAIT FOR COASTAL AREAS

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High resolution unstructured grid for wave forecasting at coastal areas

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High resolution unstructured grid for wave forecasting at coastal areas

COMPARISON WITH IN-SITU BUOY: