FY 1985

Comparison of El Niño events off the Pacific Northwest

Cannon, G.A., R.K. Reed, and P.E. Pullen

In El Niño North: Niño Events in the Eastern Subarctic Pacific Ocean, W.S. Wooster and D.L. Fluharty (eds.), Washington Sea Grant, Seattle, WA, 75–84 (1985)

Observations show that El Niño events of 1940-41, 1957-58, and 1982-83 had large coastal effects off Washington and British Columbia. Subsurface temperature anomalies were comparable during the three episodes, and average profiles between the coast and 127°W had anomalies of about 1.5°C at 100 m; individual anomalies sometimes exceeded 3°C, with the highest values near the coast. Positive anomalies were observed to extend over 200 km offshore and to depths of about 500 m. These scales were similar to those farther north in the Gulf of Alaska and were about half the offshore extent off southern California. Monthly average sea level anomalies showed that the largest increases occurred almost simultaneously from California to Alaska. Thus we suggest these data support the concept that the events are initiated by long ocean waves but that subsequent development is strongly affected by anomalous coastal winds.