Application of acoustic technologies to study the temporal and spatial distributions of the Pacific hake (Merluccius productus) in the California Current System

2016 ◽  
Vol 139 (4) ◽  
pp. 2173-2173
Author(s):  
Dezhang Chu ◽  
Rebecca Thomas ◽  
Julia Clemons ◽  
Sandy Parker-Stetter ◽  
John Pohl ◽  
...  
Keyword(s):  
Current System ◽  
California Current ◽  
Spatial Distributions ◽  
California Current System ◽  
Merluccius Productus ◽  
The Pacific ◽  
Temporal And Spatial ◽  
Acoustic Technologies

Comparisons within and between years resulting in contrasting recruitment of Pacific hake (Merluccius productus) in the California Current System

2000 ◽  
Vol 57 (7) ◽  
pp. 1434-1447 ◽  
Author(s):  
Michael M Mullin ◽  
Erica Goetze ◽  
Stace E Beaulieu ◽  
Jacqueline M Lasker
Keyword(s):  
Overall Survival ◽  
Current System ◽  
Survival Rates ◽  
California Current ◽  
Ekman Transport ◽  
California Current System ◽  
Merluccius Productus ◽  
The Difference ◽  
Simple Ratio ◽  
Overall Survival Rates

In a search for correlates and possible causes of the difference in recruitment success of Pacific hake (Merluccius productus) of the 1981 and 1984 year-classes, we analyzed (by optical plankton counter) the distribution into sizes of preserved zooplankton samples from stations with and without larval hake in winter and spring of these two years. We also assessed the onshore/offshore distributions of larvae, potential for geostrophic and Ekman transport, and their overall survival rates. Cluster analyses of biovolume spectra led to the development of a simple ratio of "medium" to "small + large" zooplankton that statistically separated stations within a year where larval hake were likely to be found from those where they were unlikely to be found. This biovolume ratio was independent of temperature, and the same ratio statistically distinguished stations where larval hake tended to occur in spring 1998. However, we found no property or process that might explain why the 1984 year-class was spectacularly successful.

scholarly journals Reconstruction of Diffusion Coefficients and Power Exponents from Single Lagrangian Trajectories

Fluids ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 111
Author(s):  
Leonid M. Ivanov ◽  
Collins A. Collins ◽  
Tetyana Margolina
Keyword(s):  
Black Sea ◽  
Diffusion Coefficients ◽  
Current System ◽  
Mean Square Displacement ◽  
California Current ◽  
The Black Sea ◽  
Mean Square ◽  
California Current System ◽  
The Mean ◽  
Non Gaussian

Using discrete wavelets, a novel technique is developed to estimate turbulent diffusion coefficients and power exponents from single Lagrangian particle trajectories. The technique differs from the classical approach (Davis (1991)’s technique) because averaging over a statistical ensemble of the mean square displacement (<X2>) is replaced by averaging along a single Lagrangian trajectory X(t) = {X(t), Y(t)}. Metzler et al. (2014) have demonstrated that for an ergodic (for example, normal diffusion) flow, the mean square displacement is <X2> = limT→∞τX2(T,s), where τX2 (T, s) = 1/(T − s) ∫0T−s(X(t+Δt) − X(t))2 dt, T and s are observational and lag times but for weak non-ergodic (such as super-diffusion and sub-diffusion) flows <X2> = limT→∞≪τX2(T,s)≫, where ≪…≫ is some additional averaging. Numerical calculations for surface drifters in the Black Sea and isobaric RAFOS floats deployed at mid depths in the California Current system demonstrated that the reconstructed diffusion coefficients were smaller than those calculated by Davis (1991)’s technique. This difference is caused by the choice of the Lagrangian mean. The technique proposed here is applied to the analysis of Lagrangian motions in the Black Sea (horizontal diffusion coefficients varied from 105 to 106 cm2/s) and for the sub-diffusion of two RAFOS floats in the California Current system where power exponents varied from 0.65 to 0.72. RAFOS float motions were found to be strongly non-ergodic and non-Gaussian.

scholarly journals Persistent spatial structuring of coastal ocean acidification in the California Current System

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
F. Chan ◽  
J. A. Barth ◽  
C. A. Blanchette ◽  
R. H. Byrne ◽  
F. Chavez ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Current System ◽  
California Current ◽  
Coastal Ocean ◽  
California Current System ◽  
Spatial Structuring

scholarly journals Surface Stress and Atmospheric Boundary Layer Response to Mesoscale SST Structure in Coupled Simulations of the Northern California Current System

2019 ◽  
Vol 148 (1) ◽  
pp. 259-287
Author(s):  
R. M. Samelson ◽  
L. W. O’Neill ◽  
D. B. Chelton ◽  
E. D. Skyllingstad ◽  
P. L. Barbour ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Wind Stress ◽  
Current System ◽  
California Current ◽  
Heat Fluxes ◽  
Neutral Stability ◽  
Northern California ◽  
Coupling Coefficients ◽  
California Current System ◽  
Northern California Current

Abstract The influence of mesoscale sea surface temperature (SST) variations on wind stress and boundary layer winds is examined from coupled ocean–atmosphere numerical simulations and satellite observations of the northern California Current System. Model coupling coefficients relating the divergence and curl of wind stress and wind to downwind and crosswind SST gradients are generally smaller than observed values and vary by a factor of 2 depending on planetary boundary layer (PBL) scheme, with values larger for smoothed fields on the 0.25° observational grid than for unsmoothed fields on the 12-km model grid. Divergence coefficients are larger than curl coefficients on the 0.25° grid but not on the model grid, consistent with stronger scale dependence for the divergence response than for curl in a spatial cross-spectral analysis. Coupling coefficients for 10-m equivalent neutral stability winds are 30%–50% larger than those for 10-m wind, implying a correlated effect of surface-layer stability variations. Crosswind surface air temperature and SST gradients are more strongly coupled than downwind gradients, while the opposite is true for downwind and crosswind heat flux and SST gradients. Midlevel boundary layer wind coupling coefficients show a reversed response relative to the surface that is predicted by an analytical model; a predicted second reversal with height is not seen in the simulations. The relative values of coupling coefficients are consistent with previous results for the same PBL schemes in the Agulhas Return Current region, but their magnitudes are smaller, likely because of the effect of mean wind on perturbation heat fluxes.

scholarly journals Remote forcing of subsurface currents and temperatures near the northern limit of the California Current System

2016 ◽  
Vol 121 (10) ◽  
pp. 7244-7262 ◽  
Author(s):  
Zelalem Engida ◽  
Adam Monahan ◽  
Debby Ianson ◽  
Richard E. Thomson
Keyword(s):  
Current System ◽  
California Current ◽  
Northern Limit ◽  
California Current System ◽  
Remote Forcing
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