1. RD Instruments Home of the ADCP Coastal & Inland Business Unit 1. Why Waves? 2. Waves Features 3. Waves Observed

2. RD Instruments Home of the ADCP Coastal & Inland Business Unit Why Waves?  Critical Factor for Coastal Region  Beaches … summer fun, winter destruction  Coastal economy  Safety  Shipping & Boating: ocean routes, coastal lanes  Coastal Destruction: storm surges, tsunamis  Coastal and Offshore Engineering  Shore Protection, Structures: design, survival  Mechanism for restoring natural equilibrium  Energy Source: Wave & Tidal Power

3. RD Instruments Home of the ADCP Coastal & Inland Business Unit Specific Examples Vessel Berthing Structure Design Sediment Transport Estuary Processes Air / Sea Interaction Oil Spill Response

4. RD Instruments Home of the ADCP Coastal & Inland Business Unit Vessel Berthing Direction #1 Direction #2 Biased Direction

5. RD Instruments Home of the ADCP Coastal & Inland Business Unit Structure Design To Build A Jetty Direction #1 Direction #2 Biased Direction

6. RD Instruments Home of the ADCP Coastal & Inland Business Unit Sediment Transport Direction #1 Direction #2 Biased Direction

7. RD Instruments Home of the ADCP Coastal & Inland Business Unit Background Wave characteristics Wave characteristics  Periodic oscillation that propagates through space  Transfers energy but not mass Engineering & Science Interest: Energy Variation Engineering & Science Interest: Energy Variation  With frequency  With direction (and frequency)

8. RD Instruments Home of the ADCP Coastal & Inland Business Unit Describing Waves Frequency (time variation) Frequency (time variation) sets Wavelength for wave type Direction (propagation through space) Direction (propagation through space) Height (2 x amplitude) Height (2 x amplitude) Energy  (height 2 ) x wavelength Energy  (height 2 ) x wavelength

9. RD Instruments Home of the ADCP Coastal & Inland Business Unit Wave Words Figures taken from Oceanography of the British Columbia Coast, Richard E. Thompson

10. RD Instruments Home of the ADCP Coastal & Inland Business Unit Background 1-d … wave propagates along line 1-d … wave propagates along line  Single wave: sinusoidal variation, amplitude, period  Wave group 2-d … wave propagates across plane: direction 2-d … wave propagates across plane: direction Two classes: long & short wavelength Two classes: long & short wavelength  Relative to water depth  Energy of short waves decays with depth

11. RD Instruments Home of the ADCP Coastal & Inland Business Unit Two Wave Types

12. RD Instruments Home of the ADCP Coastal & Inland Business Unit Wave Orbits

13. RD Instruments Home of the ADCP Coastal & Inland Business Unit Orbital Currents

14. RD Instruments Home of the ADCP Coastal & Inland Business Unit Background Two categories: sea and swell (co-exist) Two categories: sea and swell (co-exist)  Sea  High frequency, short waves  Surface variation appears random (snapshot)  Energy from local winds  Swell  Lower frequency, longer waves  Surface appears corrugated (more coherent), movement of crests more apparent  Energy from distant storms

15. RD Instruments Home of the ADCP Coastal & Inland Business Unit Waves Spectrum WIND SUN, MOON STORMS, TSUNAMIS Tides

16. RD Instruments Home of the ADCP Coastal & Inland Business Unit Storms & Swell Strength Strength Duration Duration Fetch Fetch

17. RD Instruments Home of the ADCP Coastal & Inland Business Unit Storms & Swell

18. RD Instruments Home of the ADCP Coastal & Inland Business Unit Waves at Beach

19. RD Instruments Home of the ADCP Coastal & Inland Business Unit Refraction at Headland

20. RD Instruments Home of the ADCP Coastal & Inland Business Unit Reflection, Standing Waves

21. RD Instruments Home of the ADCP Coastal & Inland Business Unit Background Wave Group: More than one wave Wave Group: More than one wave  Interfere (reinforce, attenuate)  Amplitude of resulting wave shape can vary along line (e.g. sets of waves arriving at beach) Boundaries: reflections, standing wave Boundaries: reflections, standing wave Resonance: forcing at natural oscillation period of system leads to efficient transfer of energy Resonance: forcing at natural oscillation period of system leads to efficient transfer of energy