Development of a Hierarchy of Nested Models to Study the California Current System

Shulman, Igor; Kindle, John C.; deRada, Sergio; Anderson, Stephanie; Penta, Bradley

doi:10.1061/40734(145)6

Cited by 25 publications

(22 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Chapman (1985) and Flather (1976) conditions are prescribed for the free-surface elevation and depth-averaged velocities, respectively, normal to the open boundaries. The openboundary data are provided every 12 h by the model output of 2001 in the Navy Coastal Ocean Model (NCOM) and the California Current System (CCS; Shulman et al 2004). Following the best nesting strategy found by Springer et al (2009), radiation and nudging conditions are applied at all open boundaries for both the three-dimensional velocities and tracers of temperature and salinity, and sponge layers are adopted at the western and southern boundaries, using diffusivity and viscosity equal to 100 m 2 s 21 and tapered over 150 km to their interior values.…”

Section: A Model Configurationmentioning

confidence: 99%

Toward an Uncertainty Budget for a Coastal Ocean Model

Kim

Samelson

Snyder

2011

Monthly Weather Review

View full text Add to dashboard Cite

Estimates of three components of an uncertainty budget for a coastal ocean model in a wind-forced regime are made based on numerical simulations. The budget components behave differently in the shelf regime, inshore of the 200-m isobath, and the slope-interior regime, between the 200-m isobath and a fixed longitude (1268W) that is roughly 150 km offshore. The first of the three budget components is an estimate of the uncertainty in the ocean state given only a known history of wind stress forcing, with errors in the wind forcing estimated from differences between operational analyses. It is found that, over the continental shelf, the response to wind forcing is sufficiently strong and deterministic that significant skill in estimating shelf circulation can be achieved with knowledge only of the wind forcing, and no ocean data, for wind fields with these estimated errors. The second involves initial condition error and its influence on uncertainty, including both error growth with time from well-known initial conditions and error decay with time from poorly known initial conditions but with well-known wind forcing. The third component is that of boundary condition error and its influence on the interior solutions, including the dependence of that influence on the specific location along the boundary of the boundary condition error. Boundary condition errors with amplitude comparable to the root-mean-square variability at the boundary lead eventually to errors equal to the root-mean-square variability in the slope-interior regime, and somewhat smaller errors in the shelf regime. Covariance estimates based on differences of the wind-forced solutions from the ensemble mean are not dramatically different from those based on the full fields, and do not show strong state dependence.

show abstract

Section: A Model Configurationmentioning

confidence: 99%

Toward an Uncertainty Budget for a Coastal Ocean Model

Kim

Samelson

Snyder

2011

Monthly Weather Review

View full text Add to dashboard Cite

show abstract

“…[8] Data for initial and boundary conditions are derived from Navy Coastal Ocean Model (NCOM) [Shulman et al, 2004]. The California Current System (CCS) domain extends from 30°N to 49°N and from 115°W to 135°W in spherical coordinates at 1/12°(9 -10 km) horizontal resolution.…”

Section: Initial and Boundary Conditionsmentioning

confidence: 99%

“…114, C02010, doi:10.1029/2008JC004863, 2009 jet at Cape Blanco, mesoscale eddies, or realistic flow in the offshore region. On the other hand, these features of the largescale circulation have been simulated in models of the California Current System (CCS) [e.g., Batteen, 1997;Shulman et al, 2004], but the horizontal (typically 9-10 km) and vertical grid resolutions and temporal resolution of the forcing are inadequate to simulate details of the circulation on the narrow (10 -50 km) Oregon shelf. In the cases where the entire CCS is modeled at sufficiently high spatial resolution [Marchesiello et al, 2003;Powell et al, 2006], little attention has been paid to comparing the shelf circulation with observations.…”

Section: Introductionmentioning

confidence: 99%

A nested grid model of the Oregon Coastal Transition Zone: Simulations and comparisons with observations during the 2001 upwelling season

et al. 2009

Self Cite

View full text Add to dashboard Cite

[1] The Oregon Coastal Transition Zone (OCTZ) extends several hundred kilometers offshore where shelf flows interact with the northern California Current. A primitive-equation numerical ocean model is used to study the upwelling circulation in this region from 1 May to 1 November 2001. This OCTZ model obtains initial and boundary conditions from a larger-scale model of the California Current System and forcing from a regional atmospheric model product. The model results are compared with extensive in situ and remotely sensed data, and the model is found to provide a realistic representation of flows both over the shelf and in the broader OCTZ. Simulation of coastal sea level and shelf currents over the complex topography of the central Oregon coast is improved quantitatively relative to previous regional models. A particularly significant qualitative improvement is realistic representation of coastal jet separation and eddy formation offshore of Cape Blanco. Three-dimensional Lagrangian analysis of water parcel displacement shows that the surface waters inshore of the separated jet are upwelled from near the bottom along the shelf as far north as 45.5°N. A large eddy, which incorporates some of this upwelled water and carries it farther westward, forms offshore in the late summer. Ensemble simulations show a distinction between the strongly deterministic response to wind forcing over the shelf and the more unstable, less predictable jet separation and offshore eddy formation processes in the region near Cape Blanco.

show abstract

“…Global NCOM provides boundary conditions for an NCOM‐based regional model of the California Current [NCOM CCS, Shulman et al , 2004]. The NCOM CCS has a horizontal resolution of about 9 km and is used with two different vertical coordinate systems: (1) a purely sigma‐coordinate grid with 30 layers, and (2) the same 40‐layer, hybrid grid used in the global model.…”

Section: Description Of Hierarchy Of Ncom‐based Different Resolution mentioning

confidence: 99%

Modeling of upwelling/relaxation events with the Navy Coastal Ocean Model

et al. 2007

View full text Add to dashboard Cite

[1] The Navy Coastal Ocean Model (NCOM) is a free-surface, primitive-equation model that is under development at the Naval Research Laboratory (NRL). The NCOM-based model of the Monterey Bay area is evaluated during a series of upwelling and relaxation wind events in August-September of 2000. The model receives open boundary conditions from a regional NCOM implementation of the California Current System and surface fluxes from the Navy Coupled Ocean/Atmosphere Mesoscale Prediction System (COAMPS TM )(COAMPS is a registered trademark of the Naval Research Laboratory). Issues investigated in this study are: NCOM-based model simulations of upwelling and relaxation events, coupling to COAMPS, use of sigma versus hybrid (sigma-z) vertical grids, and coupling with a larger-scale model on the open boundaries. The NCOM simulations were able to reproduce the observed sequence of the upwelling and relaxation events, which can be attributed, in part, to the good agreement between the observed and COAMPS winds. Comparisons with the mooring observations show that COAMPS overestimates shortwave radiation values, which makes the NCOM modeled SSTs too warm in comparison with observations. The NCOM runs forced with different resolution atmospheric forcing (3 versus 9 km) do not show significant differences in the predicted SSTs and mixed-layer depths at the mooring locations. At the same time, during the extended upwelling event, the model runs forced with 3 and 9 km resolution COAMPS fields show differences in the surface circulation patterns, which are the most distinct in the southern portion of the model domain. The model run with 9-km forcing develops a northward flow along the coast, which is not present in the run with 3-km forcing and in observations (for example, HF radar-derived radials). Comparison of the wind patterns of the 3-and 9-km products shows a weakening of the 9-km wind stress along the southern coast of the NCOM model domain, which is responsible for the development of the artificial northward flow in the NCOM run with 9-km forcing.

show abstract

Development of a Hierarchy of Nested Models to Study the California Current System

Cited by 25 publications

References 9 publications

Toward an Uncertainty Budget for a Coastal Ocean Model

Toward an Uncertainty Budget for a Coastal Ocean Model

A nested grid model of the Oregon Coastal Transition Zone: Simulations and comparisons with observations during the 2001 upwelling season

Modeling of upwelling/relaxation events with the Navy Coastal Ocean Model

Contact Info

Product

Resources

About