El Niño-Forced Temperature and Sea Level along the Central California Coast during 1997-98

Abstract

Beginning in the spring of 1997, we observed increases in daily-averaged sea level at San Francisco and sea surface temperatures at the Farallon Islands located west of San Francisco. An array of 3 temperature sensors deployed offshore of Davenport (north of Santa Cruz) on the shelf in 120 m of water showed a rise in temperature throughout the water column and a deepening of the thermocline associated with the higher sea levels. The sea level and temperature increases are partially forced by coastally-trapped waves that formed near the equator and propagated northward along the coast of central California. In addition, unusually strong winds blowing to the north contributed to downwelling conditions that further increased sea level and temperatures at the coast in the fall and winter. By November, 1997, the sea temperatures to over 100 m depth on the shelf were above 15 degrees C, with some of the highest sea level anomalies ever recorded at San Francisco occurring during major storms. Near the end of February 1998, both sea level at San Francisco and temperatures at depth on the shelf at Davenport abruptly dropped (over 30 cm and about 5 degrees C) over a relatively short time period of several days.

This abstract is from Monterey Bay National Marine Sanctuary Symposium, Sanctuary Currents '99, Climate Change and the Sanctuary, Poster Session, 1999.