The California Current system in the Southern California Bight and the Santa Barbara Channel

Abstract

Abstract.Recent IntroductionThe California Current system is traditionally described in terms of three major components: first, the California Current itself, historically held to be a broad, relatively sluggish equa- In the analysis presented here, several aspects of this traditional picture are challenged. First, we find that the synoptic CC just outside the bight (we define the bight as the region east of the Santa Rosa Ridge and including the SB Channel ( Figure 2b)) is neither broad nor sluggish but, rather, tends to be jet-like, as was found during the coastal transition zone (CTZ) experiment off northern California [Brink and Cowles, 1991].Because the CC moves onshore and offshore seasonally, the average picture is a broad, slow feature, but this is not representative of the synoptic current or even of the seasonal average maps. Second, we find that the average geostrophically balanced flow off southern California is divided by the Santa Rosa Ridge, with poleward flow in the bight and equatorward flow offshore, except in spring when an equatorward anomaly weakens or reverses the poleward flow in the bight. Third, we find that wind stress curl over the SC Bight is strong enough and of the right sign to explain the observed poleward flow inshore of the SR Ridge in terms of a Sverdrup balance. In contrast, the observed CC just outside the bight cannot be similarly explained: wind stress curl offshore of the SR Ridge 7695

Sediment transport on the Palos Verdes shelf, California

“…Currents on the PV shelf are influenced primarily by tides and regional-scale circulation (Hickey, 1992;Bray et al, 1999;Noble et al, 2002;Noble et al, 2009). Previous modeling efforts assumed that waves were the primary agent of sediment resuspension at 60 m on the PV shelf, and that resuspended sediment was transported by currents with a mean flow of $ 0.05 m s À 1 toward the northwest.…”

Carbon Isotope Measurements of Surface Seawater from a Time-Series Site Off Southern California

“…Environmental changes in the SCB are linked to long-term, interannual patterns, such as El Niño-Southern Oscillation (ENSO), rather than to seasonal cycles (Bray et al 1991). The surface waters Figure 2 The average surface currents and salinity values in the Southern California Bight in (a) spring and (b) summer from 1984-1995.…”

“…Color indicates salinity and "X" indicates our NBP sampling site. High salinities along the coast are associated with upwelling (Bray et al 1991). in the SCB originate primarily from the CCS and are therefore more nutrient-rich, less saline, and cooler, except when periodic ENSO events occur (PSCB 1990). ENSO events cause cooler surface waters to be replaced with nutrient-poor, warmer waters and a deeper surface mixed layer.…”

“…The poleward surface flow of the Southern California Countercurrent is strongest during the summer months and continues through fall and winter. In spring, when equatorward winds along the southern California coast are strongest, the northward flow weakens or reverses, allowing an equatorward surface flow to prevail (Bray et al 1991;PSCB 1990) (Figure 2). …”

“…The numerous basins, narrow continental shelf, and steep slopes throughout the SCB region allow deep water to exist near shore (Bray et al 1991;PSCB 1990). …”