Variability in the eastern equatorial Pacific Ocean during 1986-1988

Journal Article · Wed Aug 15 04:00:00 EDT 1990 · Journal of Geophysical Research; (USA)

DOI:https://doi.org/10.1029/JC095iC08p13195· OSTI ID:5932602

McPhaden, M J; Hayes, S P ^[1]

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1. National Oceanic and Atmospheric Administration, Seattle, WA (USA)

The authors examine variability in the eastern equatorial Pacific during 1986-1988 using conductivity-temperature-depth data, velocity and temperature data from equatorial moorings between 110{degree}W and 140{degree}W, and wind data from a basin scale zonal array of islands and moorings between 110{degree}W and 165{degree}E. The period studied coincides with the El Nino/Southern Oscillation (ENSO) event of 1986-1987 and a subsequent cold event in 1988. Weak warm sea surface temperature anomalies first appeared in the eastern equatorial Pacific in mid-1986 and increased to >1{degree}C in September-November 1986 in association with a 30 cm s{sup {minus}1} weakening of the South Equatorial Current and a 20- to 40-m depression of the thermocline. These warm anomalies lasted until early 1988, after which a large-scale shoaling of the thermocline led to sea surface temperatures more than 3{degree}C colder than climatology. Year-to-year fluctuations in the eastern pacific were related primarily to zonal wind variations in the central and western Pacific. Westerly wind stress anomalies of 0.02-0.05 N m{sup {minus}2} were observed between 140{degree}W and 165{degree}E from the latter half of 1986 until the end of 1987; these were replaced by easterly wind anomalies of similar magnitude between 157{degree}W and 165{degree}E in 1988. Energetic intraseasonal fluctuations with periods of 2-3 months were also prominent in zonal current, temperature, and dynamic height time series. These fluctuations propagate eastward at approximately first baroclinic mode Kelvin wave phase speeds and are forced west of the date line by episodes of westerly winds. Extrema in several oceanic variables occurred in association with these waves, though their precise dynamical link to the ENSO cycle is unclear from their data.

• OSTI ID: 5932602
• Journal Information: Journal of Geophysical Research; (USA), Journal Name: Journal of Geophysical Research; (USA) Vol. 95:C8; ISSN 0148-0227; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540110
540310 -- Environment
Aquatic-- Basic Studies-- (1990-)
58 GEOSCIENCES
580000* -- Geosciences
ATMOSPHERIC CIRCULATION
CURRENTS
EQUATOR
FLUCTUATIONS
MONITORING
OCEANIC CIRCULATION
OCEANOGRAPHY
PACIFIC OCEAN
SALINITY GRADIENTS
SEAS
SOUTHERN OSCILLATION
SURFACE WATERS
TEMPERATURE GRADIENTS
TEMPERATURE MEASUREMENT
VARIATIONS
WATER CURRENTS
WIND