Abstract:
Hydrographic, tidal, and meteorological data collected near
Newport, Oregon, were analyzed to determine the relative contributions
of temperature, salinity, and air pressure variations to the
recorded departures of sea level from mean sea level.
Nearshore the steric and recorded sea levels exhibited a
similar seasonal oscillation, with high sea levels in winter and low
sea levels in summer.
Analysis of the steric topography indicated the presence of two
distinct regions off Oregon, one extending from shore to 45 nm, and
the other from 65 nm offshore to seaward of NH 165. The seasonal
oscillations of sea level were approximately six months out of phase
in the two regions.
The nearshore region was greatly influenced by upwelling and
local runoff, while the offshore region was dominated by the Columbia
River plume which flows south during the summer months.
Redacted for privacy
Steric departures were of greater magnitude than air pressure
departures, but no single dominant cause of sea level oscillation
could be identified, thus justifying the labeling of this region as a
transition zone from steric to pressure dominance in sea level
determination.
Thermal and haline components of the steric departure were
shown to be of comparable magnitude and in phase. The range of
steric departures was approximately 16 cm, a figure compatible with
ranges reported for stations of similar latitude.
