Subtidal velocity correlation scales on the northern California shelf

Dever, Edward P.

doi:10.1029/96jc03451

Cited by 20 publications

(16 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…1) that alongshore currents y are well correlated over alongshore scales of at least 80 km (the extent of the mooring array), while acrossshelf currents u are uncorrelated at alongshore scales as short as 10 km. For isotropic random incompressible flow (e.g., Batchelor 1953), alongshore correlation scales for alongshore currents would be somewhat larger than for cross-shelf currents, but the discrepancy would be nowhere near as dramatic as that found by Kundu and Allen. Comparably complete measurements from other continental shelf locations have produced similar results for length scales, for example, for Peru near 158S (Brink et al 1980, their appendixes), off northern California (Dever 1997), off southern California (Winant 1983), and in the Middle Atlantic Bight (S. Lentz 2015, personal communication). It thus seems fairly likely that the scale discrepancy of the two velocity components may be a common property of continental shelf currents.…”

Section: Introductionmentioning

confidence: 60%

Continental Shelf Baroclinic Instability. Part I: Relaxation from Upwelling or Downwelling

Brink

2016

Journal of Physical Oceanography

View full text Add to dashboard Cite

There exists a good deal of indirect evidence, from several locations around the world, that there is a substantial eddy field over continental shelves. These eddies appear to have typical swirl velocities of a few centimeters per second and have horizontal scales of perhaps 5-10 km. These eddies are weak compared to typical, wind-driven, alongshore flows but often seem to dominate middepth cross-shelf flows. The idea that motivates the present contribution is that the alongshore wind stress ultimately energizes these eddies by means of baroclinic instabilities, even in cases where obvious intense fronts do not exist. The proposed sequence is that alongshore winds over a stratified ocean cause upwelling or downwelling, and the resulting horizontal density gradients are strong enough to fuel baroclinic instabilities of the requisite energy levels. This idea is explored here by means of a sequence of idealized primitive equation numerical model studies, each driven by a modest, nearly steady, alongshore wind stress applied for about 5-10 days. Different runs vary wind forcing, stratification, bottom slope, bottom friction, and Coriolis parameter. All runs, both upwelling and downwelling, are found to be baroclinically unstable and to have scales compatible with the underlying hypothesis. The model results, combined with physically based scalings, show that eddy kinetic energy generally increases with bottom slope, stratification, wind impulse (time integral of the wind stress), and inverse Coriolis parameter. The dominant length scale of the eddies is found to increase with increasing eddy kinetic energy and to decrease with Coriolis parameter.

show abstract

Section: Introductionmentioning

confidence: 60%

Continental Shelf Baroclinic Instability. Part I: Relaxation from Upwelling or Downwelling

Brink

2016

Journal of Physical Oceanography

View full text Add to dashboard Cite

show abstract

“…As previously described, our model did not contain this type of interactive behavior. In addition, along-and cross-shore correlation scales of the observed cross-shore subtidal velocity in the region (Dever 1997b) are relatively short (15 to 30 km), suggesting pointto-point mooring comparisons such as done here may not adequately resolve the spatial variability of the cross-shore current. Due to the climatological nature of our study, we suspect any errors in cross-shore transport more likely result from a misrepresentation of the mean flow.…”

Section: Discussionmentioning

confidence: 99%

Influence of larval behavior on transport and population connectivity in a realistic simulation of the California Current System

Drake¹,

Edwards²,

Morgan³

et al. 2013

J Mar Res

View full text Add to dashboard Cite

Using an implementation of the Region Ocean Modeling System, we investigate the influence of larval vertical swimming on spring dispersal for nearshore invertebrate species in the California Current System (CCS), with a focus on central California and the Bodega Bay area. Larvae are given a suite of idealized behaviors designed to reveal the importance of the surface boundary layer (SBL) to transport and settlement. Larvae remain near 5 m, 30 m, or transition between these depths using various strategies, including diel vertical migration (DVM) and ontogenetic vertical migration. Some behaviors result in modeled densities qualitatively similar to observed cross-shelf larval distributions. By remaining primarily below the SBL, larvae released from central California are 500 times more likely to be retained within 5 km of the coast at 30 days from release relative to those that stay near surface, and 145 times more likely to settle along the coast within a 30 to 60 day pelagic larval duration. For most behaviors, nearshore retention over time could be approximated as a modified exponential decay process. Vertical swimming also greatly affects alongshore dispersal, with each behavior resulting in a unique structure of alongshore settlement. Maintaining a depth near 30 m increases settlement throughout most of the CCS by at least an order of magnitude relative to passive larvae. Remaining near surface reduces settlement from Pt. Conception to Pt. Arena, but has less of an effect north of Cape Mendocino. Relative to passive larvae, DVM increases settlement in regional "hotspots," but does not greatly alter overall recruitment in the CCS, and ontogenetic vertical migration increases settlement for central California regions south of Bodega Bay.

show abstract

“…One is the uncertainty in coordinate rotation, mentioned above (Smith, 1981). Another is the apparent ubiquity of small-scale (5-10 km) eddies or meanders over many continental shelves that are evident because of short correlation length scales for cross-shelf currents (e.g., Kundu and Allen, 1976;Winant, 1983;Dever, 1997). These mask weaker, largerscale interior cross-shelf flows.…”

Section: Wind-driven Upwellingmentioning

confidence: 99%

Cross-Shelf Exchange

Brink

2016

Annu. Rev. Mar. Sci.

123

View full text Add to dashboard Cite

Abstract:Cross-shelf exchange dominates the pathways and rates by which nutrients, biota and materials on the continental shelf are delivered and removed. These transports are limited by Earth's rotation, which inhibits flow from crossing isobaths. Thus, cross-shelf transports are generally weak compared to alongshore flows, and this leads to interesting observational issues. Cross-shelf flows are enabled by turbulent mixing processes, by nonlinear processes (such as momentum advection), and by time-dependence. Thus, there is a wide range of possible effects that can allow these critical transports, and different natural settings are often governed by differing mixes of processes. Examples of representative transport mechanisms are discussed, and possible observational and theoretical paths to future progress are explored.

show abstract

Subtidal velocity correlation scales on the northern California shelf

Abstract: Background and Observations

Cited by 20 publications

References 36 publications

Continental Shelf Baroclinic Instability. Part I: Relaxation from Upwelling or Downwelling

Continental Shelf Baroclinic Instability. Part I: Relaxation from Upwelling or Downwelling

Influence of larval behavior on transport and population connectivity in a realistic simulation of the California Current System

Cross-Shelf Exchange

Contact Info

Product

Resources

About