Dynamic geography of small pelagic fish populations in the California Current System on the regime time scale (1931–1997)

2002 ◽  
Vol 59 (12) ◽  
pp. 1980-1988 ◽  
Author(s):  
Rubén Rodríguez-Sánchez ◽  
Daniel Lluch-Belda ◽  
Héctor Villalobos ◽  
Sofia Ortega-García
Keyword(s):  
Time Scale ◽  
Large Scale ◽  
Environmental Variability ◽  
Current System ◽  
California Current ◽  
Regime Shifts ◽  
Population Changes ◽  
California Current System ◽  
Geographical Variations ◽  
Sardine Population

Climate regime shifts in the Northeast Pacific appear to have forced population size changes associated with major geographical variations in the position of the center of distribution and bulk of biomass of Pacific sardine (Sardinops caeruleus). These findings help explain the disappearance of sardines around 60 years ago at the northern part of the California Current System and their return following the 1980s. The spatial processes described here differ from those suggesting that environmental regime shifts lead to progressive increase–decrease of stock abundance associated with homogeneous expansion–contraction of its distribution range around a fixed geographical center. Sardine population changes are seemingly related to environmental variability, whereas the spatial pattern of abundance for the northern anchovy (Engraulis mordax) appears to be inversely related to sardine population abundance. Anchovies increased where and when sardines were either absent or at a low population level. Thus, from the long-term and large-scale perspective, neither sardine nor anchovy populations conform to the simple homogeneous geographical range changes usually assumed. The sardine population changes its location within the ocean habitat in an evolving progression over a multidecadal time scale.

Salinity Variations in the Southern California Current*

2005 ◽  
Vol 35 (8) ◽  
pp. 1421-1436 ◽  
Author(s):  
Niklas Schneider ◽  
Emanuele Di Lorenzo ◽  
Pearn P. Niiler
Keyword(s):  
Large Scale ◽  
Southern California ◽  
Current System ◽  
California Current ◽  
Southern California Bight ◽  
Small Scale ◽  
Climate Indices ◽  
California Current System ◽  
The Mean ◽  
Salinity Variations

Abstract Hydrographic observations southwestward of the Southern California Bight in the period 1937–99 show that temperature and salinity variations have very different interannual variability. Temperature varies within and above the thermocline and is correlated with climate indices of El Niño, the Pacific decadal oscillation, and local upwelling. Salinity variability is largest in the surface layers of the offshore salinity minimum and is characterized by decadal-time-scale changes. The salinity anomalies are independent of temperature, of heave of the pycnocline, and of the climate indices. Calculations demonstrate that long-shore anomalous geostrophic advection of the mean salinity gradient accumulates along the mean southward trajectory along the California Current and produces the observed salinity variations. The flow anomalies for this advective process are independent of large-scale climate indices. It is hypothesized that low-frequency variability of the California Current system results from unresolved, small-scale atmospheric forcing or from the ocean mesoscale upstream of the Southern California Bight.

scholarly journals Can we use sea surface temperature and productivity proxy records to reconstruct Ekman upwelling?

2019 ◽  
Vol 15 (6) ◽  
pp. 1985-1998
Author(s):  
Anson Cheung ◽  
Baylor Fox-Kemper ◽  
Timothy Herbert
Keyword(s):  
Surface Temperature ◽  
Sea Surface Temperature ◽  
Large Scale ◽  
Current System ◽  
California Current ◽  
Sea Surface ◽  
California Current System ◽  
Proxy Records ◽  
Multiple Variables ◽  
Ekman Upwelling

Abstract. Marine sediments have greatly improved our understanding of the climate system, but their interpretation often assumes that certain climate mechanisms operate consistently over all timescales of interest and that variability at one or a few sample sites is representative of an oceanographic province. In this study, we test these assumptions using modern observations in an idealized manner mimicking paleo-reconstruction to investigate whether sea surface temperature and productivity proxy records in the Southern California Current System can be used to reconstruct Ekman upwelling. The method uses extended empirical orthogonal function (EEOF) analysis of the covariation of alongshore wind stress, chlorophyll, and sea surface temperature as measured by satellites from 2002 to 2009. We find that EEOF1 does not reflect an Ekman upwelling pattern but instead much broader California Current processes. EEOF2 and 3 reflect upwelling patterns, but these patterns are timescale dependent and regional. Thus, the skill of using one site to reconstruct the large-scale dominant patterns is spatially dependent. Lastly, we show that using multiple sites and/or multiple variables generally improves field reconstruction. These results together suggest that caution is needed when attempting to extrapolate mechanisms that may be important on seasonal timescales (e.g., Ekman upwelling) to deeper time but also the advantage of having multiple proxy records.

Corrigendum to “Large-scale bloom of Akashiwo sanguinea in the Northern California current system in 2009” [Harmful Algae 37 (2014) 38–46]

Harmful Algae ◽  
2015 ◽  
Vol 44 ◽  
pp. 63
Author(s):  
Angelicque E. White ◽  
Katie S. Watkins-Brandt ◽  
S. Morgaine McKibben ◽  
A. Michelle Wood ◽  
Matthew Hunter ◽  
...  
Keyword(s):  
Large Scale ◽  
Current System ◽  
California Current ◽  
Harmful Algae ◽  
Northern California ◽  
California Current System ◽  
Northern California Current ◽  
Akashiwo Sanguinea

Large-scale bloom of Akashiwo sanguinea in the Northern California current system in 2009

Harmful Algae ◽  
2014 ◽  
Vol 37 ◽  
pp. 38-46 ◽  
Author(s):  
Angelicque E. White ◽  
Katie S. Watkins-Brandt ◽  
S. Morgaine McKibben ◽  
A. Michelle Wood ◽  
Matthew Hunter ◽  
...  
Keyword(s):  
Large Scale ◽  
Current System ◽  
California Current ◽  
Northern California ◽  
California Current System ◽  
Northern California Current ◽  
Akashiwo Sanguinea

scholarly journals Large-Scale Structure in Wind Forcing over the California Current System in Summer

2017 ◽  
Vol 145 (10) ◽  
pp. 4227-4247 ◽  
Author(s):  
Melanie R. Fewings
Keyword(s):  
Wind Velocity ◽  
Time Scales ◽  
Large Scale ◽  
Current System ◽  
California Current ◽  
Large Scale Structure ◽  
Scale Structure ◽  
California Current System ◽  
The North ◽  
North And South

The wind that drives oceanic eastern boundary upwelling systems is highly variable. In many locations, the standard deviation of wind velocity on time scales of days to weeks is larger than the mean. In the ~1600-km-long California Current System (CCS), the spatial decorrelation scale of the wind fluctuations is ~400–800 km, suggesting wind fluctuations in the north and south ends of the system are not related. Yet, there is also the suggestion in the literature of a larger-scale structure in the fluctuations. Here, empirical orthogonal function (EOF) analysis of buoy and satellite wind velocities confirms the existence of that structure. This analysis covers a larger spatial domain than previous EOF studies in the CCS and, to allow for propagation of the wind fluctuations, includes an approach for calculating Hilbert EOFs from time series with gaps. The large-scale structure in the wind fluctuations is a quasi-dipole pattern spanning the coastline from Washington through California. It accounts for ~60% of the wind velocity variance on time scales of days to weeks. The time-mean wind velocity, showing a continuous zone of intensified wind along the coast, is deceptive. When the northern half of the CCS is in a relaxation state, the southern half often experiences intensified winds, and vice versa. There should be a resulting out-of-phase structure in oceanic upwelling. The out-of-phase wind fluctuations in the north and south parts of the CCS may affect the forcing of oceanic coastal-trapped waves, mesoscale eddy generation at capes, and offshore export of carbon.

scholarly journals Offshore transport of particulate organic carbon in the California Current System by mesoscale eddies

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Caitlin M. Amos ◽  
Renato M. Castelao ◽  
Patricia M. Medeiros
Keyword(s):  
Organic Carbon ◽  
Particulate Organic Carbon ◽  
Coastal Water ◽  
Large Scale ◽  
Current System ◽  
Mesoscale Eddy ◽  
California Current ◽  
California Current System ◽  
Upwelled Water ◽  
Offshore Transport

Abstract The California Current System is characterized by upwelling and rich mesoscale eddy activity. Cyclonic eddies generally pinch off from meanders in the California Current, potentially trapping upwelled water along the coast and transporting it offshore. Here, we use satellite-derived measurements of particulate organic carbon (POC) as a tracer of coastal water to show that cyclones located offshore that were generated near the coast contain higher carbon concentrations in their interior than cyclones of the same amplitude generated offshore. This indicates that eddies are in fact trapping and transporting coastal water offshore, resulting in an offshore POC enrichment of 20.9 ± 11 Gg year−1. This POC enrichment due to the coastally-generated eddies extends for 1000 km from shore. This analysis provides large-scale observational-based evidence that eddies play a quantitatively important role in the offshore transport of coastal water, substantially widening the area influenced by highly productive upwelled waters in the California Current System.

scholarly journals Annual and Interannual Variability in the California Current System: Comparison of an Ocean State Estimate with a Network of Underwater Gliders

2018 ◽  
Vol 48 (12) ◽  
pp. 2965-2988 ◽  
Author(s):  
Katherine D. Zaba ◽  
Daniel L. Rudnick ◽  
Bruce D. Cornuelle ◽  
Ganesh Gopalakrishnan ◽  
Matthew R. Mazloff
Keyword(s):  
Interannual Variability ◽  
Large Scale ◽  
Current System ◽  
Potential Temperature ◽  
California Current ◽  
Late Summer ◽  
Near Surface ◽  
State Estimate ◽  
California Current System ◽  
Annual Cycles

AbstractA data-constrained state estimate of the southern California Current System (CCS) is presented and compared with withheld California Cooperative Oceanic Fisheries Investigations (CalCOFI) data and assimilated glider data over 2007–17. The objective of this comparison is to assess the ability of the California State Estimate (CASE) to reproduce the key physical features of the CCS mean state, annual cycles, and interannual variability along the three sections of the California Underwater Glider Network (CUGN). The assessment focuses on several oceanic metrics deemed most important for characterizing physical variability in the CCS: 50-m potential temperature, 80-m salinity, and 26 kg m−3 isopycnal depth and salinity. In the time mean, the CASE reproduces large-scale thermohaline and circulation structures, including observed temperature gradients, shoaling isopycnals, and the locations and magnitudes of the equatorward California Current and poleward California Undercurrent. With respect to the annual cycle, the CASE captures the phase and, to a lesser extent, the magnitude of upper-ocean warming and stratification from late summer to early fall and of isopycnal heave during springtime upwelling. The CASE also realistically captures near-surface diapycnal mixing during upwelling season and the semiannual cycle of the California Undercurrent. In terms of interannual variability, the most pronounced signals are the persistent warming and downwelling anomalies of 2014–16 and a positive isopycnal salinity anomaly that peaked with the 2015–16 El Niño.

A Large-Scale Seasonal Modeling Study of the California Current System

2003 ◽  
Vol 59 (5) ◽  
pp. 545-562 ◽  
Author(s):  
Mary L. Batteen ◽  
Nicholas J. Cipriano ◽  
James T. Monroe
Keyword(s):  
Large Scale ◽  
Current System ◽  
California Current ◽  
California Current System ◽  
Modeling Study
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