Schematic of a sinusoidal wave.

Wind waves. (a) Open ocean waves in the Gulf of Tehuantepec (February 7, 2009), under wind speeds of 20–25 m/sec, including actively breaking waves, old foam patches, and streaks of foam (K. Melville, personal communication, 2009). (b) Example of a surface wave spectrum (spectral density) in which ocean swell and wind-seas are well separated in frequency. Source: From National Data Buoy Center (2006). (c, d) Directional wave spectrum (spectral density) and spectrum, without clear separation between swell and the wind-sea, from the NE Pacific (station 46006, 40°53' N 137°27' W, May 16, 2009. In (c), wave periods are from about 25 sec at the center of the ring to 4 sec at the outer ring. Blue is low energy, purple is high. Direction of the waves is the same as direction relative to the center of the circle. Gray arrow in center indicates wind direction. “Hs” indicates significant wave height. Figure 8.2c can also be found in the color insert. Source: part c is from NOAA Wavewatch III (2009) and part d is from National Data Buoy Center (2009).

(a) Significant wave height (m) and (b) peak wave period (s) and direction (vectors) for one day (May 16, 2009). Figure 8.3a and 8.3b can also be found in the color insert. Source: From NOAA Wavewatch III (2009).

(a) Surf zone, looking toward the south at the Scripps Pier, La Jolla, CA. Source: From CDIP (2009). (b) Rip currents, complex pattern of swell, and alongshore flow near the head of a submarine canyon near La Jolla, CA, Photo courtesy of Steve Elgar (2009).

Types of breaking waves: (I) spilling breaker, (II) plunging breaker, and (III) surging breaker. Source: From Komar (1998).

Features of the surf zone. Source: From Komar and Holman (1986).

Sumatra Tsunami (December 26, 2004). (a) Tsunami wave approaching the beach in Thailand Source: From Rydevik, 2004.(b) Simulated surface height two hours after earthquake. Source: From Smith et al., 2005.(c) Global reach: simulated maximum sea-surface height and arrival time (hours after earthquake) of wave front. Figure 8.7c can also be found in the color insert. Source: From Titov et al., 2005.

Schematic of a simple interfacial internal wave in a two-layer flow. Source: After Gill (1982).

Internal wave observations. (a) Temperature as a function of time and depth on June 16, 1997 at location shown in (b) (Lerczak, personal communication, 2010). (b) Map of mooring location in water of 15 m depth west of Mission Bay, California. Source: From Lerczak (2000). (c) Ocean surface west of Scripps Institution of Oceanography (map in b) on a calm day; the bands are the surface expression of internal waves propagating toward shore. (Shaun Johnston, personal communication, 2010).

Schematic of properties of internal waves. The direction of phase propagation is given by the wavevector (k, m) (heavy arrows). The phase velocity (c_p) is in the direction of the wavevector. The group velocity (c_g) is exactly perpendicular to the wavevector (shorter, lighter arrows).

(a) Rotary spectra from a current meter at 55 m depth in the Mid-Atlantic bight: bold is clockwise and thin is counterclockwise; the dashed curve is the modified Garrett-Munk spectrum. Source: From Levine, 2002.

(b) Velocity variance (variability) observed along a section crossing the Hawaiian Ridge, which is located just below the bottom of the figure at 0 km; the black rays are the (group velocity) paths expected for an internal wave with frequency equal to the M₂ tide; distance (m) is from the center of the ridge. Source: From Cole, Rudnick, Hodges, & Martin, 2009. This figure can also be found in the color insert.

(c) Breaking internal solitary wave, over the continental shelf off Oregon. The image shows acoustic backscatter: reds indicate more scatter and are related to higher turbulence levels. Figure 8.11 can also be found in the color insert. ©American Meteorological Society. Reprinted with permission. Source: From Moum et al., 2003.

The equilibrium tide. (a) Tide-generating force due to the moon or sun. (b) Earth-moon-sun alignment during spring tide, which also includes the case when the moon is opposite the sun. Source: After NOAA (2008). (c) Alignment during neap tide. In (a), the F's are the net gravitational acceleration at the antipodal, center, and sublunar points, and the T's are the net tidal gravitational accelerations.

Tides at La Jolla, California. Data from NOAA CO-OPS (2010).

Maps of (a) cotidal (phase) lines (°) for the M₂ tide (lunar semidiurnal). Source: From Ray (1999).

Maps of (b) tidal amplitude (cm) for the M₂ tide (lunar semidiurnal). Source: From Ray (1999).

Tidal effects on Georges Bank. (a) Schematic circulation and (b) summer temperature (°C) structure. TMF = Tidal Mixing Front. SBF = Shelf Break Zone. Source: From Hu et al. (2008).

(c) Chlorophyll a concentration (mg/m³) on October 8, 1997, from the SeaWiFS satellite. Figure 8.15c can also be found in the color insert. Source: From Sosik (2003).