Spring climate and salinity in the San Francisco Bay Estuary

Water Resources Research
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Abstract

Salinity in the San Francisco Bay Estuary almost always experiences its yearly maximum during late summer, but climate variability produces marked interannual variations. The atmospheric circulation pattern impacts the estuary primarily through variations of runoff from rainfall and snowmelt from the Sierra Nevada and, secondarily, through variations in the near-surface salinity in the coastal ocean. While winter precipitation is the primary influence upon salinity in the estuary, spring climate variations also contribute importantly to salinity fluctuations. Spring atmospheric circulation influences both the magnitude and the timing of freshwater flows, through anomalies of precipitation and temperature. To help discriminate between the effects of these two influences, the record is divided into subsets according to whether spring conditions in the region are cool and wet, warm and wet, cool and dry, or warm and dry. Warm springs promote early snowmelt-driven flows, and cool springs result in delayed flows. In addition to effects of winter and spring climate variability operating on the watershed, there are more subtle effects that are transmitted into the estuary from the coastal ocean. These influences are most pronounced in cool and dry springs with high surface salinity (SS) in the coastal ocean versus cool and wet springs with low SS in the coastal ocean. A transect of SS records at stations from the mouth to the head of the bay suggests that the coastal ocean anomaly signal is attenuated from the mouth to the interior of the estuary. In contrast, a delayed, postsummer signal caused by winter and spring runoff variations from the upstream watershed are most pronounced at the head of the estuary and attenuate toward the mouth.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Spring climate and salinity in the San Francisco Bay Estuary
Series title Water Resources Research
DOI 10.1029/92WR02152
Volume 29
Issue 2
Year Published 1993
Language English
Publisher American Geophysical Union
Contributing office(s) Pacific Regional Director's Office, San Francisco Bay-Delta, California Water Science Center, Toxics Substances Hydrology Program
Description 11 p.
First page 293
Last page 303
Country United States
State California
Other Geospatial San Francisco Bay
Online Only (Y/N) N
Additional Online Files (Y/N) N