Characteristics of All Wind-generated Waves
Deep Water Waves
Shallow Water Waves
Other Water Waves
Crest, trough, wavelength
Wave Height (H)
Wave Steepness
Period (T)
A wave in water depth > one-half wavelength
Sea vs. swell
What determines wave height?
Waves in water depth less than 1/20 of wavelength
Often associated with surf zone
Variety of surf depends on shape of bottom◦ Plunging◦ Spilling◦ Surging
spilling
plunging
surging
Deep water wave◦ Speed = 1.56T
Shallow water wave◦ Speed = 3.1 times square root of water depth
Bending of wave crests Waves approach beach at angle One part of crest reaches shallow water first
and slows down Waves become more parallel to shore
Wave Refraction
note distribution of wave energy most of energy strikes headlands causes erosion of headland, deposition in
bays coastal straightening occurs
disturbance of ocean floor speed greater than 700 km/hr wavelength greater than 200 km crests can exceed 30 m as reach shore
http://nctr.pmel.noaa.gov/