A numerical study of the Somali coastal undercurrents

Esenkov, Oleg E.; Olson, Donald B.

doi:10.1016/s0967-0645(01)00152-7

Cited by 10 publications

(9 citation statements)

References 19 publications

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“…The physical model used here is MICOM configured for the Arabian Sea (Esenkov, 2000). In MICOM each isopycnic layer is governed by the shallow water equations.…”

Section: Physical Modelmentioning

confidence: 99%

“…It has 15 isopycnic layers below the mixed layer. The vertical structure of the upper thermocline is reasonably well resolved with seven layers in the upper 400 m. With the use of this relatively high spatial resolution the intense eddy activity that dominates the system (Flagg and Kim, 1998;Kim et al, 2001) is quite well reproduced (Esenkov, 2000). The global solution of MICOM after 50 years of integration from an initialization with Levitus data (Levitus and Boyer, 1994) is used for the initial and open boundary conditions of the regional model.…”

Section: Physical Modelmentioning

confidence: 99%

“…The global solution of MICOM after 50 years of integration from an initialization with Levitus data (Levitus and Boyer, 1994) is used for the initial and open boundary conditions of the regional model. Formulation of open boundary conditions is based on Bleck and Sun (1996) and presented in Esenkov and Olson (2002). Interface pressure nudging, damping of the tendency term in the continuity equation, and enhanced viscosity in the momentum equations are applied in a finite-width "sponge" zone near the open boundaries.…”

Section: Physical Modelmentioning

confidence: 99%

“…Interface pressure nudging, damping of the tendency term in the continuity equation, and enhanced viscosity in the momentum equations are applied in a finite-width "sponge" zone near the open boundaries. The width of the sponge zone was determined experimentally and amounted to 7 grid points (Esenkov, 2000). The open-boundary model was validated first through a detailed comparison of the results with the output of the global model (Esenkov, 2000).…”

Section: Physical Modelmentioning

confidence: 99%

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Biophysical isopycnic-coordinate modelling of plankton dynamics in the Arabian Sea

2005

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A Nutrients-Phytoplankton-Zooplankton-Detritus (NPZD) ecosystem model is coupled to the Miami Isopycnic-Coordinate Ocean Model (MICOM) to study plankton dynamics in the Arabian Sea.Experiments oriented to testing the NPZD-MICOM coupled model sensitivity to variations in several parameters are performed. Particular attention is paid to the rates of detritus sinking and maximum phytoplankton growth rate. The coarse features of the blooms are captured by all the experiments considered, and agree with earlier models for the biological activity of the region. Intensity, duration, and peaks of the blooms are found to be quite sensitive to the parameter choices. The existence of an offshore deep chlorophyll maximum in the model is found to be closely related to the increase of the detritus sinking rate. The use of temperaturedependent maximum growth rate of phytoplankton and the increase of detritus sinking rate are shown to improve model results compared with in situ and satellite observations.The differences between the present results and those from previous modelling efforts in the region, where few-or multi-layer hydrodynamical models or even fixed-level hydrodynamical models have been employed, are found to be in the same range as the differences among the results from the various sensitivity experiments presented here. This indicates that a small uncertainty in the knowledge of the ecosystem model parameters can be more important in ecosystem modelling than the uncertainty associated to the differences in the vertical coordinate representation of the underlying hydrodynamical model.There are still biological processes, such as denitrification which affect the vertical distribution of nutrient concentrations, that are not included neither in the previous works in the area nor in the present work. This might mask any potential advantages of the present MICOM-NPZD coupled model, especially at mid-depths in the ocean.

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“…The physical model used here is MICOM configured for the Arabian Sea (Esenkov, 2000). In MICOM each isopycnic layer is governed by the shallow water equations.…”

Section: Physical Modelmentioning

confidence: 99%

Section: Physical Modelmentioning

confidence: 99%

Section: Physical Modelmentioning

confidence: 99%

Section: Physical Modelmentioning

confidence: 99%

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Biophysical isopycnic-coordinate modelling of plankton dynamics in the Arabian Sea

2005

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“…To simulate transport of passive individuals in a state of diapause, we used the Miami isopycnic coordinate ocean model (MICOM; Bleck et al 1989), configured for the Arabian Sea (Esenkov and Olson 2002). For our simulations, MICOM was coupled to a nutrient-phytoplankton-zooplankton-detritus (NPZD) model to create a water column light field with realistic light extinction (Olascoaga et al in press).…”

Section: Model Developmentmentioning

confidence: 99%

Mechanisms for emergence from diapause of Calanoides carinatus in the Somali current

Idrisi

Olascoaga

Garraffo

et al. 2004

Limnology & Oceanography

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We studied mechanisms that might control the emergence of the last juvenile stage of Calanoides carinatus from diapause in the Arabian Sea. Diapaused copepods are modeled as Lagrangian particles that include a simplified means for lipid catabolism during diapause. The advective field for the particles, which are released at intermediate and deep layers off the Somali shelf, is determined by a regional version of the Miami isopycnic coordinate model (MICOM). Dormant copepods emerge from diapause in response to either onshore advection (physical upwelling) or depletion of lipid reserves to an assumed critical level (internal biological clock). The majority of the diapaused copepods that successfully complete their life cycle are those retained within the coastal upwelling zone and emerge as a consequence of depletion of the lipid reserves.

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