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Coastal-trapped waves are studied in a two-layered, non-flat shelf model. Internal Kelvin wave and quasi-geostrophic waves appear as eigenmodes of the system. The latter reduce to the familiar barotropic shelf waves only in the limit of vanishing stratification. With strong stratification, i.e., where the internal Kelvin wave phase speed is larger than the phase speed of the quasi-geostrophic wave, quasi-geostrophic waves are bottom-trapped. Resonant coupling occurs when the two types of waves have compatible phase speeds; in this case, the relative amplitude distribution of the resonant modes is very sensitive to the change of the baroclinic radius of deformation. Implications of this work for the study of shelf water response to external disturbances are briefly discussed.

The compressibilities of water and seawater solutions have been determined from the sound speed measurements of Wilson [1959, 1960] by an iterative method. The compressibilities have been fit to (±0.02 × 10−6 bar−1 for pure water and ±0.01 × 10−6 bar−1 for seawater) an extended bulk modulus equation, (V0−VP)/P = D/(B + A1P + A2P2), where V0 and VP are the specific volumes at applied pressures of zero and P, D is Vw0 for pure water, and B, A1, and A2 are temperature and salinity dependent constants. The compressibilities of seawater derived from the sound data agree with Li's [1967] results at only 1 atm and agree with Crease's [1962] results at only low pressures. Since the maximum error in the compressibilities derived from sound speed data is within ±0.02 × 10−6 bar−1, our P-V-T results based on sound speed data are more reliable than any direct measurements made to date.

Using the high‐pressure (0 to 1000 bars) sound‐velocity measurements of Wilson (1960), an equation of state for PVT properties of water and seawater has been developed based on a modified Tait equation of the form V°−VPV°P=1B+A1P+A2P2, in which V° is the specific volume at atmospheric pressure, VP the specific volume at pressure P, and B, A1, and A2 are functions of temperature and salinity. The equation has been fit with a maximum deviation in compressibility of 0.01×10−6 bar−1 for seawater and 0.02×10−6 bar−1 for pure water. The data from this equation will yield specific volumes that show the excellent consistency of Ekman's (1908) measurements with the sound data. The results for pure water show a definite shift in Kell and Whalley's (1965) measurements and the superiority of the PVT data generated from the sound data to direct experimental measurements.