Coastal Ocean Circulation Model Research Articles

MODELING MICROBIAL WATER QUALITY AT A BEACH IMPACTED BY MULTIPLE NON-POINT SOURCES

Monitoring microbial water quality is essential for recreational beaches in order to protect human health. To evaluate the relative importance and impacts of various types of non-point microbial sources at a subtropical beach (Hobie Beach, Miami, USA), we utilized a coastal ocean circulation model (Delft3D) with a microbe transport-fate model. Those non-point sources include beach sediment, dog feces, bather shedding, and rainfall runoff. The hydrodynamic model results agreed well with tidal elevations recorded by a nearby NOAA tidal station and also field data collected by pressure sensors, acoustic Doppler current profiler (ADCP). We modeled enterococci levels from four different types of non-point sources on the beach and Staphylococcus aureus levels from only the bather shedding. Model results suggest that dog feces are spotty sources of enterococci and can result in transient spikes of enterococci levels for hours. Beach sands are pervasive sources of enterococci and may explain observed persistent elevations of enterococci levels at this site. Runoff may also significantly increase enterococci levels during rainfall events while bather shedding contribution of enterococci is almost negligible. Bather is the only Staphylococcus aureus source considered in the study and simulated levels are in the same order as prior field measurements.

Argo data assimilation in ocean general circulation model of Northwest Pacific Ocean

The Argo temperature and salinity profiles in 2005–2009 are assimilated into a coastal ocean general circulation model of the Northwest Pacific Ocean using the ensemble adjustment Kalman filter (EAKF). Three numerical tests, including the control run (CTL) (without data assimilation, which serves as the reference experiment), ensemble free run (EnFR) (without data assimilation), and EAKF experiment (with Argo data assimilation using EAKF), are carried out to examine the performance of this system. Using the restarts of different years as the initial conditions of the ensemble integrations, the ensemble spreads from EnFR and EAKF are all kept at a finite value after a sharp decreasing in the first few months because of the sensitive of the model to the initial conditions, and the reducing of the ensemble spread due to Argo data assimilation is not much. The ensemble samples obtained in this way can well represent the probabilities of the real ocean states, and no ensemble inflation is necessary for this EAKF experiment. Different experiment results are compared with satellite sea surface temperature (SST) data and the Global Temperature-Salinity Profile Program (GTSPP) data. The comparison of SST shows that modeled SST errors are reduced after data assimilation; the error reduction percentage after assimilating the Argo profiles is about 10 % on average. The comparison against the GTSPP profiles, which are independent of the Argo profiles, shows improvements in both temperature and salinity. The comparison results indicated a great error reduction in all vertical layers relative to CTL and the ensemble mean of EnFR; the maximum value for temperature and salinity reaches to 85 % and 80 %, respectively. The standard deviations of sea surface height are employed to examine the simulation ability, and it is shown that the mesoscale variability is improved after Argo data assimilation, especially in the Kuroshio extension area and along the section of 10°N. All these results suggest that this system is potentially useful for improving the simulation ability of oceanic numerical models.

Modeling the west Florida coastal ocean by downscaling from the deep ocean, across the continental shelf and into the estuaries

We arrive at a coastal ocean circulation model, suitable for downscaling from the deep ocean, across the continental shelf and into the estuaries, by nesting the unstructured grid, Finite Volume Coastal Ocean Model (FVCOM, inner model) into the structured grid, Global Hybrid Coordinate Model (HYCOM, outer model). The coastal ocean circulation model is three-dimensional, density dependent and inclusive of tides (eight constituents). A calendar year 2007 simulation for the west Florida continental shelf is quantitatively tested against in situ observations of sea level from coastal tide gauges and water column currents and temperature from moored acoustic Doppler current profilers. Agreements between model simulations and observations for both tides and low frequency variability over the calendar year demonstrate the usefulness of our approach. Model horizontal resolution varies from around 12km at the open boundary to 150m in the estuaries. Sensitivity experiments for vertical resolution led to the adoption of 21 σ-layers. Several model limitations are discussed, including seasonal steric effects and deep ocean (outer) model errors that may propagate through the inner model. With adequate observations spanning the inner model domain, we may determine when the outer model is in error at the nesting zone. This finding further highlights the need for coordinating coastal ocean observing and modeling programs. The nesting of unstructured and structured grid models is a new approach to coastal ocean circulation modeling. It provides a means for circulation hindcasts and nowcasts/forecasts, and, after combining with biological process models, may provide a framework for multi-disciplinary modeling of coastal ocean ecology from the deep ocean to the head of tides.

Tidal eddy motions in the western Gulf of Maine, Part 2: Secondary flow

The kinematics and dynamics of the tidal circulation in the western Gulf of Maine (GoM) region are investigated with focus on the secondary circulation. This study is motivated by previous research suggesting the formation and evolution of transient tidal eddy motions in a high-density scallop region off Chatham, MA. Three-dimensional flow velocity and surface elevation fields were obtained using the QUODDY finite-element coastal ocean circulation model in the barotropic mode and forced by the five most important tidal constituents in the region (M2,N2,S2,K1 and O1). The secondary flow kinematics related to the primary tidal flows feature time/space-varying convergences and divergences that are affected by the associated transient tidal eddy motions. Interestingly, the upwelling and downwelling in the study region were not dominated by the secondary circulation. Rather, the model results show that instantaneous vertical motions close to the coast and close to the bathymetric slope are mainly controlled by the divergence/convergence of the primary flow. The instantaneous secondary flow dynamics are mainly controlled by a balance between pressure gradient and Coriolis forces. Off Chatham, the surface maximum strength of the secondary flow calculated by the model is consistent with theoretical predictions of 0.025m/s. The mechanisms controlling the long-term average tidal secondary circulation, which is relevant for biological transport, are discussed.

Assimilation of HF radar-derived surface currents on tidal-timescales

A surface current observation system based on high-frequency (HF) radar has been developed for Raritan Bay and the coastal waters of New York and New Jersey. An HF radar network provides synoptic surface current maps in near-real-time that can be optimally combined with ocean circulation models using data assimilation (DA) framework to obtain the best possible estimate of a three-dimensional ocean state. A nudging or Newtonian damping scheme has been developed to assimilate HF radar data into an estuarine and coastal ocean circulation model. This model, with an extensive embedded real-time observational network, is called the New York Harbour Observing and Prediction System (NYHOPS). A nudging parameter is introduced into the equations of motion which affects the model dynamics. The data is imparted to neighbouring (three-dimensional) grid points via model dynamics. The impact of HF radar DA is analysed by computing the DA skill score (DAskill) based on the mean-square-error (mse). The DAskill is computed by comparing non-assimilated and assimilated model solutions with in-situ observations of three-dimensional currents, temperature and salinity, which have not been included in the assimilation. A positive DAskill (0∼1) represents an improvement in the model performance by assimilation. HF radar data covering Raritan Bay and the New York Bight (NYB) Apex were assimilated into the NYHOPS model in the model hindcast cycle (–24h to 0h) on a daily forecast basis for a period of 40 days. The DAskill is assessed with respect to the NYHOPS model hindcasts (daily model solutions from –24h to 0h) as well as the first day forecasts (daily model solutions from 0h to 24h). HF radar DA improved the NYHOPS model performance during both the hindcast and forecast periods. The model skill metrics for the near-surface layers in the inner-NJ shelf region shows a hindcast DAskill of 24% (14%) and forecast DAskill of 18% (7%) for horizontal velocities u: east-west component (v: north-south component), and a hindcast DAskill of 33% (38%) and forecast DAskill of 25% (30%) for temperature (salinity). The nudging scheme is robust and efficient for the HF radar DA into the NYHOPS operational forecast model. The NYHOPS-HF radar DA system is capable of importing in the observations and produce useful hindcasts/forecasts with minimum computational expense.

Far-field effects of tidal energy extraction in the Minas Passage on tidal circulation in the Bay of Fundy and Gulf of Maine using a nested-grid coastal circulation model

The Bay of Fundy in eastern Canada has the highest tides in the world. Harnessing the tidal energy in the region has long been considered. In this study, the effects of tidal in-stream energy extraction in the Minas Passage on the three-dimensional (3D) tidal circulation in the Bay of Fundy (BoF) and the Gulf of Maine (GoM) are examined using a nested-grid coastal ocean circulation model based on the Princeton Ocean Model (POM). The nested-grid model consists of a coarse-resolution (~4.5 km) parent sub-model for the GoM and a high-resolution (~1.5 km) child sub-model for the BoF. The tidal in-stream energy extraction in the model is parameterized in terms of nonlinear Rayleigh friction in the momentum equation. A suite of numerical experiments are conducted to determine the ranges of extractable tidal in-stream energy and resulting effects on the 3D tidal circulation over the Bay of Fundy and the Gulf of Maine (BoF-GoM) in terms of the Rayleigh friction coefficients. The 3D model results suggest that the maximum energy extraction in the Minas Passage increases tidal elevations and tidal currents throughout the GoM and reduces tidal elevations and circulation in the upper BoF, especially in the Minas Basin. The far-field effect of tidal energy extraction in the Passage on the 3D tidal circulation in the BoF-GoM is examined in two cases of harnessing tidal in-stream energy from (a) the entire water column and (b) the lower water column within 20 m above the bottom in the Passage. The 3D model results demonstrate that tidal in-stream energy extraction from the lower water column has less impact on the tidal elevations and circulation in the BoF-GoM than the energy extraction from the whole water column in the Minas Passage.

Variational assimilation of satellite observations in a coastal ocean model off Oregon

[1] Satellite along-track sea surface height (SSH) and multisatellite sea surface temperature (SST) maps are assimilated in a coastal ocean circulation model off Oregon. The study period is June–October 2005, featuring intensive separation of the coastal upwelling jets in the eddy-dominated coastal transition zone (CTZ). The data assimilation (DA) system combines the nonlinear Regional Ocean Modeling System (ROMS) and the Advanced Variational Regional Ocean Representer Analyzer (AVRORA) tangent linear and adjoint codes developed by our group. The variational representer DA method is implemented in a series of 6 day time windows, with initial conditions corrected at the beginning of each window. To avoid the problem of matching the model and observed SSH mean levels, the observed SSH slope has been assimilated. Location, timing, and intensity of jets and eddies in the CTZ are constrained, to improve accuracy of nonlinear model analyses and forecasts. In the case assimilating SSH alone, the geometry of the SST front is improved. SSH assimilation results in the cross-shore transport more uniformly distributed along the coast than in the free run model. An outer front is identified in the DA analyses at a distance of 200 km from the coast. A strong subsurface horizontal temperature gradient across this front influences the depth of the thermocline in an area between the front and the continental slope. The DA correction term is comparable in magnitude to dominant terms in the volume-integrated heat equation. The time-averaged DA correction term in the volume-integrated heat balance is closer to 0 in the combined SSH-SST assimilation case, than in the case assimilating SSH alone.

Simulating the three-dimensional circulation and hydrography of Halifax Harbour using a multi-nested coastal ocean circulation model

Halifax Harbour is located on the Atlantic coast of Nova Scotia, Canada. It is one of the world’s largest, ice-free natural harbours and of great economic importance to the region. A good understanding of the physical processes controlling tides, flooding, transport and dispersion, and hydrographic variability is required for pollution control and sustainable development of the Harbour. For the first time, a multi-nested, finite difference coastal ocean circulation model is used to reconstruct the three-dimensional circulation and hydrography of the Harbour and its variability on timescales of hours to months for 2006. The model is driven by tides, wind and sea level pressure, air-sea fluxes of heat, and terrestrial buoyancy fluxes associated with river and sewage discharge. The predictive skill of the model is assessed by comparing the model simulations with independent observations of sea level from coastal tide gauges and currents from moored instruments. The simulated hydrography is also compared against a new monthly climatology created from all available temperature and salinity observations made in the Harbour over the last century. It is shown that the model can reproduce accurately the main features of the observed tides and storm surge, seasonal mean circulation and hydrography, and wind driven variations. The model is next used to examine the main physical processes controlling the circulation and hydrography of the Harbour. It is shown that non-linear interaction between tidal currents and complex topography occurs over the Narrows. The overall circulation can be characterized as a two-layer estuarine circulation with seaward flow in the thin upper layer and landward flow in the broad lower layer. An important component of this estuarine circulation is a relatively strong, vertically sheared jet situated over a narrow sill connecting the inner Harbour to the deep and relatively quiescent Bedford Basin. Local wind driven variability is strongest in winter as expected but it is also shown that a significant part of the temperature and salinity variability is driven by physical processes occurring on the adjacent inner continental shelf, especially during storm and coastal upwelling events.

Interannual spring bloom variability and Ekman pumping in the coastal Gulf of Alaska

A lower trophic level ecosystem model is coupled to a three‐dimensional coastal ocean circulation model for the northwestern coastal Gulf of Alaska (CGOA) to investigate regional ecosystem dynamics on seasonal and interannual timescales. By including explicit growth limitation by light, nitrate, ammonium, silicic acid, and iron, the ecosystem model provides a comprehensive framework to investigate the combined role of macronutrients and micronutrients in shaping phytoplankton community structure. On the basis of comparisons with available in situ and remotely sensed observations for 1998 through 2002, the model reproduces the dominant modes of variability associated with the northwestern CGOA ecosystem dynamics. An empirical orthogonal function (EOF) analysis of biological and surface forcing fields suggests that, for the 5‐year period, interannual variability in peak chlorophyll concentrations during the spring bloom is related to interannual variability in the wind stress curl over the northern CGOA during the previous winter. Positive wind stress curl anomalies during winter result in enhanced Ekman pumping and, thus, nutrient upwelling on the shelf and at the shelfbreak. Since phytoplankton growth is severely light‐limited when Ekman pumping occurs, nutrient upwelling associated with the wind stress curl acts as a priming mechanism for the CGOA shelf, leading to higher peak chlorophyll concentrations during the following spring bloom. Enhanced wind stress curl and Ekman pumping are associated with the presence of a low‐pressure system in the northern CGOA, and potentially connected to the large‐scale variability of the Aleutian Low in the North Pacific.

Modeling iron limitation of primary production in the coastal Gulf of Alaska

A lower trophic level NPZD ecosystem model with explicit iron limitation on nutrient uptake is coupled to a three-dimensional coastal ocean circulation model to investigate the regional ecosystem dynamics of the northwestern coastal Gulf of Alaska (CGOA). Iron limitation is included in the NPZD model by adding governing equations for two micro-nutrient compartments: dissolved iron and phytoplankton-associated iron. The model has separate budgets for nitrate (the limiting macro-nutrient in the standard NPZD model) and for iron, with iron limitation on nitrate uptake being imposed as a function of the local phytoplankton realized Fe:C ratio. While the ecosystem model represents a simple approximation of the complex lower trophic level ecosystem of the northwestern CGOA, simulated chlorophyll concentrations reproduce the main characteristics of the spring bloom, high shelf primary production, and “high-nutrient, low-chlorophyll” (HNLC) environment offshore. Over the 1998–2004 period, model-data correlations based on spatially averaged, monthly mean chlorophyll concentrations are on average 0.7, with values as high as 0.9 and as low as 0.5 for individual years. The model also provides insight on the importance of micro- and macro-nutrient limitation on the shelf and offshore, with the shelfbreak region acting as a transition zone where both nitrate and iron availability significantly impact phytoplankton growth. Overall, the relative simplicity of the ecosystem model provides a useful platform to perform long-term simulations to investigate the seasonal and interannual CGOA ecosystem variability, as well as to conduct sensitivity studies to evaluate the robustness of simulated fields to ecosystem model parameterization and forcing. The ability of the model to differentiate between nitrate-limited, and iron-limited growth conditions, and to identify their spatial and temporal occurrences, is also a first step towards understanding the role of environmental gradients in shaping the complex CGOA phytoplankton community structure.

Evaluation of a coastal ocean circulation model for the Columbia River plume in summer 2004

Realistic hindcast of the Columbia River estuarine‐plume‐shelf circulation in summer 2004 using the Regional Ocean Modeling System nested within the Navy Coastal Ocean Model (NCOM) is quantitatively evaluated with an extensive set of observations. The model has about equal skill at tidal and subtidal properties. Tidal circulation and water properties are best simulated in the estuary, which is strongly forced and damped, but worst on the shelf. Subtidal currents are again best in the estuary. However, subtidal temperature and salinity are best simulated in the surface waters on the shelf, even inside the river plume. A comprehensive skill assessment method is proposed to evaluate the cross‐scale modeling system with a focus on the plume. The model domain is divided into five dynamical regions: estuary, near‐ and far‐field plume, near surface and deep layers. A skill score is obtained for each region by averaging the skills of different physical variables, and an overall skill is obtained by averaging the skills across the five regions. This weighting metric results in more skill weight per unit volume in the near surface layer where the plume is trapped and in the estuary. It is also demonstrated, through model/data comparison and skill assessment, that by nesting within NCOM, some important remote forcing, e.g., coastal trapped waves, are added to our model; on the other hand, some biases are also received. With a finer grid and more realistic forcing, our regional model improves skill over a larger‐scale model in modeling the shelf‐plume circulation.

Columbia River plume patterns in summer 2004 as revealed by a hindcast coastal ocean circulation model

Model hindcasts of the Columbia River (CR) plume and coastal ocean circulation in summer 2004 are used to describe the subtidal evolution of plume patterns in response to local wind and to examine the plume influence on shelf circulation. It is found that a bi‐directional plume occurs frequently on the Washington/Oregon shelf, during weak upwelling favorable wind events, during weakening of moderate upwelling favorable wind events, and during weak downwelling events. The high frequency of occurrence of the north plume branch indicates that the CR water will have a significant influence on the Washington shelf in summer.

Improve the utility of a coastal circulation model by assimilating hydrographic observations into the model momentum equation

[1] A numerical scheme is presented to assimilate hydrographic observations into the momentum equation of a limited-area coastal ocean circulation model. This new scheme has an advantage of assimilating observed hydrography into the model momentum equations and leaving the model temperature and salinity equations to be fully prognostic and is well suited for tracer studies. The performance of this new scheme is assessed using a nested-grid coastal circulation model developed for Lunenburg Bay of Nova Scotia, Canada. Model results demonstrate that this new scheme improves significantly the performance of the coastal circulation model in simulating the temperature and salinity distributions and circulation over coastal waters.

Modeling of the Cape Fear River Estuary plume

The Environmental Fluid Dynamic Code, an estuarine and coastal ocean circulation model, is used to simulate the distribution of the salinity plume in the vicinity of the mouth of the Cape Fear River Estuary, North Carolina. The individual and coupled effects of the astronomical tides, river discharge, and atmospheric winds on the spatial and temporal distributions of coastal water levels and the salinity plume were investigated. These modeled effects were compared with water level observations made by the National Oceanic and Atmospheric Administration and salinity surveys conducted by the Coastal Ocean Research and Monitoring Program. Model results and observations of salinity distributions and coastal water level showed good agreement. The simulations indicate that strong winds tend to reduce the surface plume size and distort the bulge shape near the estuary mouth due to enhanced wind-induced surface mixing. Under normal discharge conditions, tides, and light winds, the southward outwelling plume veers west. Relatively moderate winds can mechanically reverse the flow direction of the plume. Under conditions of weak to moderate winds the water column does not mix vertically to the bottom, while in strong wind cases the plume becomes vertically well mixed. Under conditions of high river discharge the plume increases in size and reaches the bottom. Vertical mixing induced by strong spring tides can also enable the plume to reach the bottom.

Hydrological Forecasting in the Oder Estuary using a Three- Dimensional Hydrodynamic Model

A three-dimensional operational hydrodynamic model, developed at the Institute of Oceanography, University of Gdansk was used to forecast hydrological conditions in the Oder Estuary. The model was based on the coastal ocean circulation model known as the Princeton Ocean Model (POM). Because of wind-driven water backup in the Oder mouth, a simplified operational model of river discharge, based on water budget in a stream channel, was developed. Linking these two models into a single system made it possible to forecast water levels, currents, water temperature, and salinity in the estuary. A good fit between the observed and computed data allowed to consider the model as a reliable environmental tool. Obtaining a hydrological forecast via a quick website access gives potential users an opportunity to predict the day-by-day course of processes that may affect different areas of human life and activities, e.g., navigation, port operations, flood protection of coastal areas; the predictions may also be used in studies of coastal processes in the estuary.

Operational hydrodynamic model for forecasting extreme hydrographic events in the Oder Estuary

A 3D operational hydrodynamic model, developed at the Institute of Oceanography, University of Gdansk, was used to forecast extreme hydrographic events in the Oder Estuary. The model was based on the coastal ocean circulation model known as the Princeton Ocean Model (POM); it was adapted to Baltic conditions and to a 48-h numerical meteorological forecast. Wind-driven water backup in the Oder mouth necessitated working out a simplified operational model of river discharge, based on water budget in a stream channel. The model generates 60-h forecasts of water levels, currents, water temperature and salinity in the estuary. As the model adequately approximates hydrographic variability in the estuary, it can be regarded as a reliable tool for storm surges forecasting and for the assessment of Oder water spread in the Baltic. The forecast is rapidly accessed on its designated website, thereby providing assistance in decision-making by emergency situation centres and bodies that are responsible for navigation safety, port operation and environmental and flood protection of coastal areas. It is intended to fine-tune the model so that a better fit between the observed and computed data is obtained.

Model simulations of the Gulf of Maine response to storm forcing

The storm response of the Gulf of Maine/Georges Bank region was investigated using the Dartmouth three‐dimensional, nonlinear, finite element coastal ocean circulation model called QUODDY, with uniform density and quadratic bottom stress. A suite of model hindcast experiments were conducted for the 4–8 February 1987 period that featured a strong nor'easter. The model was forced at the open ocean boundaries by the M2 semidiurnal tidal sea level and in the interior by realistic surface wind stresses and, in some cases, atmospheric pressure. The reference model run, with just tidal and wind stress forcing and a time‐space constant bottom drag coefficient Cd of 0.005, captured 65% of the observed detided, low‐pass filtered or “subtidal” sea level variance of a representative array of coastal and bottom pressure stations in the Gulf. However, there remained large unexplained model/observed sea level differences, particularly during the storm. Model sensitivity testing to a realistic range of constant Cd values did not improve model results significantly. However, results of a model run in which atmospheric pressure forcing, derived through linear interpolations of regional measurements, was added to wind stress forcing captured 82% of the observed subtidal sea level variance.

A Simple Method of Deriving Three-Dimensional Temperature Fields Using Remotely Sensed and In Situ Data for Application to Numerical Hydrodynamic Models of Estuaries and Bays

Abstract This paper describes the subjective interpolation method (SIM) for generating three-dimensional temperature distributions from remotely sensed sea surface temperature (SST) fields. SIM incorporates MATLAB-based cloud removal software and a method of generating synthetic temperature profiles based on observations. This approach depends on the human facility for recognizing patterns in complex images. Three-dimensional temperature fields produced by SIM are compared to analogous fields based on optimal interpolation (OI) methods by using temperature fields interpolated by the two methods to initialize a baroclinic coastal ocean circulation model. The initial SST surface fields from both methods have a bias of less than −0.5°C and rms errors of less than 1.5°C. After running for 48 h, the bias and rms errors for the OI simulations are 0.3° and 1.2°C, respectively, whereas the same errors for the SIM run are 0.7° and 0.9°C. The OI and SIM approaches can be combined to allow preprocessing of SST data ...

A Non-orthogonal Primitive Equation Coastal Ocean Circulation Model: Application to Lake Superior

A non-orthogonal coordinate primitive equation model has been developed for the study of the Keweenaw Current in Lake Superior. This model provides a more accurate fitting of the coastline. A comparison with a curvilinear orthogonal model shows that the non-orthogonal transformation model provided a better simulation of the current jet in the near-shore region. Accurate fitting of both bathymetry and irregular coastlines plays an essential role in capturing the magnitude of the Keweenaw Current and cross-shelf structure of the thermal bar near the coast. The formation of the Keweenaw Current and thermal front was directly driven by a westerly or southwesterly wind and seasonal development of stratification over steep bottom topography. Under a condition with accurate fitting of steep bathymetry, failure to resolve the irregular geometry of the coastline can result in an underestimation of the magnitude of the Keweenaw Current by about 20 cm/s.

Simulation of frontal eddies on the East Florida Shelf

[1] Frontal eddies are typical features on the cyclonic side of the Florida Current (FC) along the East Florida Shelf (EFS), producing characteristic “shingle” patterns in sea surface temperature. Intensive observations and idealized numerical analyses have described such eddies over the past three decades. Here, simulations from a high-resolution (2 to 10 km), curvilinear coastal ocean circulation model demonstrate their structure and evolution with realistic bottom topography and FC over an extended domain including the Straits of Florida and the entire EFS. Simulations agree with observations in estimating translation speed, recurrence period, strength, characteristic length-scales, and overall circulation patterns. In addition, the simulations demonstrate the interactions between the frontal eddies and the meander crests and bottom topography as they translate along the EFS. Overall, a first level of model validation has been established that will facilitate consideration of the forecast problem for frontal eddies associated with the FC on the EFS.