Near-inertial motions off the Oregon Coast

• Main Authors: Anderson, Lain, Huyer, Adriana, 1945-, Smith, Robert L. (Robert Lloyd), 1935-
• Format: Article in Journal/Newspaper
• Language: English; unknown
• Published: American Geophysical Union
• Subjects: North Atlantic
• Online Access: https://ir.library.oregonstate.edu/concern/articles/8336h3587

Near‐inertial motions were observed at all current meters in an array of five moorings spanning the continental margin off central Oregon during October 1977 to January 1978. All moorings were between 10 and 130 km from shore, in water depths between 100 m and 2500 m. Largest near‐inertial amplitudes (>30 cm/s) were observed at the uppermost current meters of the offshore moorings, although these were below the surface mixed layer. The near‐inertial energy generally decreased with increasing depth, and there was less near‐inertial energy over the continental shelf than at similar depths offshore. The energy levels observed over the shelf were about the same as observed there during summer 1973, and the energy levels observed offshore were comparable with those observed in the open North Atlantic. Horizontal coherence scales were large, exceeding 115 km during the first half of the observational period and about 60 km during the second half; estimates of the horizontal wavelength (50 km during the first half and 20 km during the second half) suggest that the coherence scale is of the order of three wavelengths. Although we did not have current data in the surface mixed layer nor wind measurements over each mooring, the available meteorological data (synoptic pressure charts and hourly wind and pressure at Newport) suggest that most of the near‐inertial energy was forced by the local wind.