The signature of El Niño off Oregon, 1982–1983

Abstract

Current and conductivity, temperature, and depth (CTD) measurements were made over the Oregon shelf near 43°N between February 1981 and April 1984 as part of a large‐scale west coast shelf experiment (SuperCODE). The data set includes a nearly continuous record of current velocity and temperature over the continental shelf off Coos Bay from May 1981 through January 1984, CTD sections off Coos Bay in January or February of each year from 1981 to 1984, and CTD sections off Newport (44.6°N) in April 1983, July 1983, and April 1984. The latter are compared with sections off Newport made during the previous two decades. Sea level from the Newport tide gage, daily sea surface temperature at Charleston (43.3°N), the alongshore component of the wind stress at 45°N and the large‐scale North Pacific atmospheric pressure pattern provide a climatological perspective. The initial manifestation of El Niño off Oregon was in October 1982: anomalously high sea level, high coastal sea surface temperature, and increased poleward flow. These effects occurred within 1 month of the onset of El Niño off Peru and preceded any local (North Pacific) atmospheric effect by 2–3 months. The anomalous local meteorological conditions, which became manifest in December and January, greatly enhanced the initial effects and inserted their own signal. The first signals of El Niño probably arrived by an oceanic path, but there is no doubt they were subsequently reinforced by anomalous atmospheric conditions.