Waves and Tides Wave movement and properties Wind and waves Waves and beaches Making a tide Tide theory Tides and basins, shores

Wave movement Longitudinal waves: E transmission in same direction Transverse waves: E transmission is perpendicular Orbital waves: E transmission across interface Height H Wavelength L Steepness H/L Period T Speed S = L/T = Lf = gT/2 Frequency f = 1/T Depth = L/2 Shallow waves: D < L/20 S = (gD) = 3.1(Dm)

Wind and Waves Wind-generated waves Capillary waves (ripples): L < 1.74 cm Gravity waves: L > 1.74 cm Sea: where wind generates waves Steepness = 1/7 whitecaps: energy loss; fully-developed Wave trains and interference Rogue waves

Surf Swell releases E at surf zone If local waves: rough, uneven surf Wave “drags” bottom L H break Circular oscillation outrun wave: plunging breakers turbulent water, air: spilling breakers (gentle slope)

Waves and Beaches Refraction Waves bend around objects Reflection/diffraction Waves reflect off objects

Waves and Beaches Storm surge Tsunamis

Tides Gravity, distance important Gravity: g = (m1m2)/r^2 Tidal force  (m1m2)/r^3 Simple model: moon above equator, no earth tilt

Tides 2: Variables elliptical orbit of earth, moon declination of moon tilt of earth

Tides 3: Land + Water Amphidromic points

Tides and Geomorphology Bays, gulfs: geomorphic features effect Open ocean: amphidromic point + Coriolis force Reversed and ebb currents Tidal bores

Waves, Tides, and Organisms Waves: high energy, turbidity in surf zone --> Stabilization, damage resistance, feeding Tides: change in H2O P, depth, salinity, T nearshore Daily effects: feeding, activity Annual effects: timing of breeding, recruitment