scholarly journals MODELACIóN NUMÉRICA DE LA CIRCULACIÓN MARINA EN LAS BAHÍAS CALLAO y MIRAFLORES

2019 ◽  
pp. 59-66
Keyword(s):  
Ocean Circulation ◽  
Pollutant Dispersion ◽  
Circulation Pattern ◽  
Ocean Model ◽  
Ocean Dynamics ◽  
Coastal Morphology ◽  
Princeton Ocean Model ◽  
Tidal Propagation ◽  
Palabras Clave ◽  
San Marcos

MODELACIóN NUMÉRICA DE LA CIRCULACIÓN MARINA EN LAS BAHÍAS CALLAO y MIRAFLORES NUMERICAL MODELING OF CIRCULATION IN CALLAO AND MIRAFLORES BAYS Mirian Centeno, Emanuel Guzmán y Paúl García Grupo de Estudio de la Dinámica Marina, Ingeniería Mecánica de Fluidos, Universidad Nacional Mayor de San Marcos, Lima 01, Perú DOI: https://doi.org/10.33017/RevECIPeru2010.0009/ RESUMEN El presente trabajo consiste en estudiar a nivel superficial la circulación marina en las bahías del Callao y Miraflores, mediante el uso del modelo numérico Princeton Ocean Model conocido como POM, el cual es un conjunto de ecuaciones y parámetros que gobiernan la dinámica oceánica. El modelo POM se empleó con la finalidad de caracterizar el patrón de circulación en el área de estudio, analizando la influencia de los forzantes viento y marea (propagación del Norte) en la generación de corrientes marinas, así como los efectos que se producen a causa de la morfología costera y la presencia de la Isla; estos factores influyen en los resultados indicando una complejidad en las corrientes marinas, como la presencia de vórtices dentro de la bahía del Callao, así también la propagación de mareas se manifiestan en el área del puerto del Callao generando las corrientes de flujo y reflujo. Conociendo la circulación marina en las Bahías de Callao y Miraflores, se podrá realizar estudios posteriores de dispersión de contaminante, descargas residuales, derrames accidentales de sustancias, así también estudios de transporte de sedimentos aportados por la presencia de los ríos Rímac y Chillón. Palabras clave: Circulación marina, Princeton Ocean Model, Bahías del Callao y Miraflores ABSTRACT The present work is related to study the surface circulation in Callao and Miraflores bays using Princeton Ocean Model (POM) model, which is a set of equations and parameters that govern the ocean dynamics. POM was used to caracterize the circulation pattern in the study area, analyzing the main influence of wind stress and tide in the generation of currents and the effects occur because of the coastal morphology and the presence of the Island, these factors influence the results indicating a complexity in the ocean currents and the presence of vortices inside the bay of Callao, also tidal propagation manifests in the area of the port of Callao, generating currents ebb and flow. In this way, knowing the ocean circulation in the Callao and Miraflores bays, further studies can be made pollutant dispersion, wastewater discharges, accidental spills of substances, and also sediment transport studies produced by the presence of Rimac and Chillon rivers. Keywords: Marine Circulation, Princeton Ocean Model, Callao y Miraflores bays.

scholarly journals Multi-grid algorithm for passive tracer transport in the NEMO ocean circulation model: a case study with the NEMO OGCM (version 3.6)

2020 ◽  
Vol 13 (11) ◽  
pp. 5465-5483
Author(s):  
Clément Bricaud ◽  
Julien Le Sommer ◽  
Gurvan Madec ◽  
Christophe Calone ◽  
Julie Deshayes ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Ocean Circulation ◽  
Circulation Model ◽  
Ocean Model ◽  
Ocean Dynamics ◽  
Global Ocean ◽  
Passive Tracer ◽  
Tracer Transport ◽  
Ocean Circulation Model ◽  
Grid Algorithm

Abstract. Ocean biogeochemical models are key tools for both scientific and operational applications. Nevertheless the cost of these models is often expensive because of the large number of biogeochemical tracers. This has motivated the development of multi-grid approaches where ocean dynamics and tracer transport are computed on grids of different spatial resolution. However, existing multi-grid approaches to tracer transport in ocean modelling do not allow the computation of ocean dynamics and tracer transport simultaneously. This paper describes a new multi-grid approach developed for accelerating the computation of passive tracer transport in the Nucleus for European Modelling of the Ocean (NEMO) ocean circulation model. In practice, passive tracer transport is computed at runtime on a grid with coarser spatial resolution than the hydrodynamics, which reduces the CPU cost of computing the evolution of tracers. We describe the multi-grid algorithm, its practical implementation in the NEMO ocean model, and discuss its performance on the basis of a series of sensitivity experiments with global ocean model configurations. Our experiments confirm that the spatial resolution of hydrodynamical fields can be coarsened by a factor of 3 in both horizontal directions without significantly affecting the resolved passive tracer fields. Overall, the proposed algorithm yields a reduction by a factor of 7 of the overhead associated with running a full biogeochemical model like PISCES (with 24 passive tracers). Propositions for further reducing this cost without affecting the resolved solution are discussed.

scholarly journals Sensitivity of modelled North Sea cod larvae transport to vertical behaviour, ocean model resolution and interannual variation in ocean dynamics

2018 ◽  
Vol 75 (7) ◽  
pp. 2413-2424 ◽  
Author(s):  
Kristina Øie Kvile ◽  
Giovanni Romagnoni ◽  
Knut-Frode Dagestad ◽  
Øystein Langangen ◽  
Trond Kristiansen
Keyword(s):  
North Sea ◽  
Ocean Circulation ◽  
Interannual Variation ◽  
Model Performance ◽  
Vertical Movement ◽  
Ocean Model ◽  
Population Connectivity ◽  
Ocean Dynamics ◽  
Model Resolution ◽  
Eggs And Larvae

Abstract Transport with ocean currents affects the spatial distribution and survival of fish eggs and larvae and thereby population connectivity. Biophysical models are commonly used to understand these dynamics. Advancements such as implementing vertical swimming behaviour and higher resolution ocean circulation models are known to improve model performance, however, the relative importance of vertical behaviour vs. ocean model resolution is elusive. Here, we use North Sea cod (Gadus morhua) as a case study to assess how vertical movement, ocean model resolution and interannual variation in ocean dynamics influence drift patterns and population connectivity. We couple a fine (1.6 km, 3 h) and coarser (4 km, 24 h) ocean model to an individual-based model for cod eggs and larvae, and compare simulations with and without vertical movement of eggs and larvae. The results are moderately influenced by vertical movement and ocean model resolution but differ substantially between years. While ocean model resolution is consistently more influential than vertical movement, the effect of vertical movement strongly depends on the spatiotemporal scale of the analyses. This study highlights which aspects of biophysical modelling of connectivity that most critically affect the results, allowing better investing computational resources and proposing goal-based guidelines for future studies.

scholarly journals The analysis of large-scale turbulence characteristics in the Indonesian seas derived from a regional model based on the Princeton Ocean Model

2012 ◽  
Vol 9 (1) ◽  
pp. 63-103
Author(s):  
K. O'Driscoll ◽  
V. Kamenkovich
Keyword(s):  
Kinetic Energy ◽  
Ocean Circulation ◽  
Regional Model ◽  
Ocean Model ◽  
Princeton Ocean Model ◽  
Turbulence Characteristics ◽  
Indonesian Seas ◽  
The North ◽  
Closure Scheme ◽  
Mixing Coefficients

Abstract. The analysis is presented of the distribution of deep ocean turbulence characteristics on the horizontal scale of order 100 km in the vicinity of the Lifamatola Sill, from the Southern Maluku Sea (north of the sill) to the Seram Sea (south of the sill). The turbulence characteristics were calculated with a regional model of the Indonesian seas circulation based on the Princeton Ocean Model (POM), incorporating the Mellor-Yamada turbulence closure scheme. The analysis has been carried out for the entire Indonesian seas region, including areas around important topographic features, such as the Lifamatola Sill, the North Sangihe Ridge, the Dewakang Sill and the North and South Halmahera Sea Sills. To illustrate results of application of the Mellor-Yamada closure scheme we have focused on the description of features of turbulence characteristics across the Lifamatola Sill because dynamically this region is very important and some estimates of mixing coefficients in this area are available. As is well known, the POM model output provides both dynamical (depth-integrated and 3-D velocities, temperature, salinity, and sea-surface-height) and turbulence characteristics (kinetic energy and master scale of turbulence, mixing coefficients of momentum, temperature and salinity, etc.). As a rule, the analysis of POM modeling results has been restricted to the study of corresponding dynamical characteristics, however the study of turbulence characteristics is essential to understanding the dynamics of the ocean circulation as well. Due to the absence of direct measurements of turbulence characteristics in the analyzed area, we argued the validity of the simulated characteristics in the light of their compatibility with some general principles. Thus, along these lines, vertical profiles of across-the-sill velocities, twice the kinetic energy of turbulence, turbulence length scale, the separate terms in the equation of kinetic energy of turbulence, the Richardson number, and finally coefficients of mixing of momentum and temperature and salinity are discussed. Average values of the vertical mixing coefficient compare well with indirect estimates previously made from diagnostic calculations based on Munk's model.

scholarly journals The Arctic and Subarctic Ocean Flux of Potential Vorticity and the Arctic Ocean Circulation*

2005 ◽  
Vol 35 (12) ◽  
pp. 2387-2407 ◽  
Author(s):  
Jiayan Yang
Keyword(s):  
Arctic Ocean ◽  
Ocean Circulation ◽  
Circulation Pattern ◽  
3D Models ◽  
Ocean Model ◽  
The Arctic ◽  
Fram Strait ◽  
The Arctic Ocean ◽  
Ocean Models ◽  
Arctic Ocean Circulation

Abstract According to observations, the Arctic Ocean circulation beneath a shallow thermocline can be schematized by cyclonic rim currents along shelves and over ridges. In each deep basin, the circulation is also believed to be cyclonic. This circulation pattern has been used as an important benchmark for validating Arctic Ocean models. However, modeling this grand circulation pattern with some of the most sophisticated ocean–ice models has been often difficult. The most puzzling and thus perhaps the most interesting finding from the Arctic Ocean Model Intercomparison Project (AOMIP), an international consortium that runs 14 Arctic Ocean models by using the identical forcing fields, is that its model results can be grouped into two nearly exact opposite patterns. While some models produce cyclonic circulation patterns similar to observations, others do the opposite. This study examines what could be possibly responsible for such strange inconsistency. It is found here that the flux of potential vorticity (PV) from the subarctic oceans strongly controls the circulation directions. For a semienclosed basin like the Arctic, the PV integral over the whole basin yields a balance between the net lateral PV inflow and the PV dissipation along the boundary. When an isopycnal layer receives a net positive PV through inflow/outflow, the circulation becomes cyclonic so that friction can generate a flux of negative PV to satisfy the integral balance. For simplicity, a barotropic ocean model is used in this paper but its application to the 3D models will be discussed. In the first set of experiments, the model with a realistic Arctic bathymetry is forced by observed inflows and outflows. In this case, there is a net positive PV inflow to the basin, due to the fact that inflow layer is thinner than that of outflow. The model produces a circulation field that is remarkably similar to the one from observations. In the second experiment, the model bathymetry at Fram Strait is modified so that the same inflows and outflows of water masses lead to a net negative PV flux into the Arctic. The circulation is reversed and becomes nearly the opposite of the first experiment. In the third experiment, the net PV flux is made to be zero by modifying again the sill depth at Fram Strait. The circulation becomes two gyres, a cyclonic one in the Eurasian Basin and an anticyclonic one in the Canada Basin. To elucidate the control of the PV integral, a second set of model experiments is conducted by using an idealized Arctic bathymetry so that the PV dynamics can be better explained without the complication of rough topography. The results from five additional experiments that used the idealized topography will be discussed. While the model used in this study is one layer, the same PV-integral constraint can be applied to any isopycnal layer in a three-dimensional model. Variables that affect the PV fluxes to this density layer at any inflow/outflow channel, such as layer thickness and water volume flux, can affect the circulation pattern. The relevance to 3D models is discussed in this paper.

scholarly journals LGM climate forcing and ocean dynamical feedback and their implications for estimating climate sensitivity

2020 ◽  
Author(s):  
Jiang Zhu ◽  
Christopher J. Poulsen
Keyword(s):  
Ocean Circulation ◽  
Climate Sensitivity ◽  
Radiative Forcing ◽  
Climate Models ◽  
Model Simulation ◽  
Ice Sheets ◽  
Ocean Model ◽  
Ocean Dynamics ◽  
True Value ◽  
Climate Forcings

Abstract. Equilibrium climate sensitivity (ECS) has been directly estimated using reconstructions of past climates that are different than today’s. A challenge to this approach is that temperature proxies integrate over the timescales of the fast feedback processes (e.g. changes in water vapor, snow, and clouds) that are captured in ECS as well as the slower feedback processes (e.g. changes in ice sheets and ocean circulation) that are not. A way around this issue is to treat the slow feedbacks as climate forcings and independently account for their impact on global temperature. Here we conduct a suite of Last Glacial Maximum (LGM) simulations using the Community Earth System Model version 1.2 (CESM1.2) to quantify the forcing and efficacy of land ice sheets (LIS) and greenhouse gases (GHG) in order to estimate ECS. Our forcing and efficacy quantification adopts the effective radiative forcing (ERF) and adjustment framework and provides a complete accounting for the radiative, topographic, and dynamical impacts of LIS on surface temperatures. ERF and efficacy of LGM LIS are −3.2 W m−2 and 1.1, respectively. The larger-than-unity efficacy is caused by the relatively larger temperature changes over land and the Northern Hemisphere subtropical oceans than those in response to a doubling of atmospheric CO2. The subtropical SST response is linked to LIS-induced wind changes and feedbacks in ocean-atmosphere coupling and clouds. ERF and efficacy of LGM GHG are −2.8 W m−2 and 0.9, respectively. The lower efficacy is primarily attributed to a smaller cloud feedback at colder temperatures. Our simulations further demonstrate that the direct ECS calculation using the forcing, efficacy, and temperature response in CESM1.2 overestimates the true value in the model by 25 % due to the neglect of slow ocean dynamical feedback. This is supported by the greater cooling (6.8 °C) in a fully coupled LGM simulation than that (5.3 °C) in a slab ocean model simulation with ocean dynamics disabled. The majority (67 %) of the ocean dynamical feedback is attributed to dynamical changes in the Southern Ocean, where interactions between ocean stratification, heat transport, and sea-ice cover are found to amplify the LGM cooling. Our study demonstrates the value of climate models in the quantification of climate forcings and the ocean dynamical feedback, which is necessary for an accurate direct ECS estimation.

scholarly journals Multi-grid algorithm for passive tracer transport in NEMO ocean circulation model: a case study with NEMO OGCM (version 3.6)

2020 ◽  
Author(s):  
Clément Bricaud ◽  
Julien Le Sommer ◽  
Madec Gurvan ◽  
Christophe Calone ◽  
Julie Deshayes ◽  
...  
Keyword(s):  
Spatial Resolution ◽  
Ocean Circulation ◽  
Circulation Model ◽  
Ocean Model ◽  
Ocean Dynamics ◽  
Global Ocean ◽  
Passive Tracer ◽  
Tracer Transport ◽  
Ocean Circulation Model ◽  
Grid Algorithm

Abstract. Ocean biogeochemical models are key tools for both scientific and operational applications. Nevertheless the cost of running these models is often expensive because of the large number of biogeochemical tracers. This has motivated the development of multi-grid approaches where ocean dynamics and tracer transport are computed on grids of different spatial resolution. However, existing multi-grid approaches to tracer transport in ocean modelling do not allow to compute ocean dynamics and tracer transport simultaneously. This paper describes a new multi-grid approach developed for accelerating the computation of passive tracer transport in the NEMO ocean circulation model. In practice, passive tracer transport is computed at runtime on a grid with coarser spatial resolution than the hydrodynamics, which allows to reduce the CPU cost of computing the evolution of tracer. We describe the multi-grid algorithm, its practical implementation in the NEMO ocean model, and discuss its performance on the basis of a series of sensitivity experiments with global ocean model configurations. Our experiments confirm that the spatial resolution of hydrodynamical fields can be coarsened by a factor 3 in both horizontal directions without significantly affecting the resolved passive tracer fields. Overall, the proposed algorithm yields a reduction by a factor 7 of the overhead associated with running a full biogeochemical model like PISCES (with 24 passive tracers). Propositions for reducing further this cost without affecting the resolved solution are discussed.

scholarly journals The role of vertical shear on the horizontal oceanic dispersion

2015 ◽  
Vol 12 (5) ◽  
pp. 2073-2096
Author(s):  
A. S. Lanotte ◽  
R. Corrado ◽  
G. Lacorata ◽  
L. Palatella ◽  
C. Pizzigalli ◽  
...  
Keyword(s):  
Ocean Circulation ◽  
Vertical Velocity ◽  
Marine Biology ◽  
Pollutant Dispersion ◽  
Ocean Model ◽  
Three Dimensions ◽  
Vertical Shear ◽  
Time Variability ◽  
Horizontal Dispersion ◽  
Basin Scale

Abstract. The effect of vertical shear on the horizontal dispersion properties of passive tracer particles on the continental shelf of South Mediterranean is investigated by means of observative and model data. In-situ current measurements reveal that vertical velocity gradients in the upper mixed layer decorrelate quite fast (∼ 1 day), whereas basin-scale ocean circulation models tend to overestimate such decorrelation time because of finite resolution effects. Horizontal dispersion simulated by an eddy-permitting ocean model, like, e.g., the Mediterranean Forecasting System, is mosty affected by: (1) unresolved scale motions, and mesoscale motions that are largely smoothed out; (2) poorly resolved time variability of vertical velocity profiles in the upper layer. For the case study we have analysed, we show that a suitable use of kinematic parameterisations is helpful to implement realistic statistical features of tracer dispersion in two and three dimensions. The approach here suggested provides a functional tool to control the horizontal spreading of small organisms or substance concentrations, and is thus relevant for marine biology, pollutant dispersion as well as oil spill applications.

Influence of Bathymetry on the Performance of Regional Scale Model

2017 ◽  
Vol 68 (1) ◽  
pp. 104
Author(s):  
P. Anand ◽  
P.V. Hareesh Kumar
Keyword(s):  
Ocean Circulation ◽  
Regional Scale ◽  
Three Dimensional ◽  
Coastal Region ◽  
Circulation Model ◽  
Ocean Model ◽  
Scale Model ◽  
Princeton Ocean Model ◽  
Nearshore Processes ◽  
Fine Resolution

<p class="p1"><span class="Apple-converted-space"> </span>A three dimensional ocean circulation model (Princeton Ocean Model) is utilised to study the thermohaline variability of the eastern Arabian Sea associated with changes in the three input bathymetry data sets, viz. ETOPO5 (E5), Modified ETOPO5 (ME5) and ME5 further modified based on actual fine resolution data collected using Multibeam echo-sounder (MEN5). The temperature and salinity measurements made onboard INS Sagardhwani for the period July 2000 is utilised to validate the model. Simulations of temperature using Princeton Ocean Model show good improvement in the coastal region with MEN5 bathymetry data (RMS error of 0.71 °C and correlation coefficient of 0.98). The study highlights the choice of fine resolution bathymetry data in the simulation of nearshore processes, where bathymetry is very complex.</p>

scholarly journals Wind-Driven Response of the Northern Indian Ocean to Climate Extremes*

2007 ◽  
Vol 20 (13) ◽  
pp. 2978-2993 ◽  
Author(s):  
Tommy G. Jensen
Keyword(s):  
Indian Ocean ◽  
Ocean Circulation ◽  
Bay Of Bengal ◽  
El Niño ◽  
Arabian Sea ◽  
El Nino ◽  
Ocean Model ◽  
La Niña ◽  
Northern Indian Ocean ◽  
La Nina

Abstract Composites of Florida State University winds (1970–99) for four different climate scenarios are used to force an Indian Ocean model. In addition to the mean climatology, the cases include La Niña, El Niño, and the Indian Ocean dipole (IOD). The differences in upper-ocean water mass exchanges between the Arabian Sea and the Bay of Bengal are investigated and show that, during El Niño and IOD years, the average clockwise Indian Ocean circulation is intensified, while it is weakened during La Niña years. As a consequence, high-salinity water export from the Arabian Sea into the Bay of Bengal is enhanced during El Niño and IOD years, while transport of low-salinity waters from the Bay of Bengal into the Arabian Sea is enhanced during La Niña years. This provides a venue for interannual salinity variations in the northern Indian Ocean.

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