scholarly journals A High-resolution Biogeochemical Model (ROMS 3.4 + bio_Fennel) of the East Australian Current System

2018 ◽  
Author(s):  
Carlos Rocha ◽  
Christopher A. Edwards ◽  
Moninya Roughan ◽  
Paulina Cetina-Heredia ◽  
Colette Kerry
Keyword(s):  
Climate Change ◽  
High Resolution ◽  
Numerical Models ◽  
Current System ◽  
Ocean Model ◽  
Ecosystem Dynamics ◽  
Biogeochemical Model ◽  
East Australian Current ◽  
Surface Patterns ◽  
Insight Into

Abstract. Understanding phytoplankton dynamics is critical across a range of topics, spanning from fisheries management to climate change mitigation. It is particularly interesting in the East Australian Current (EAC) System, as the region’s eddy field strongly conditions nutrient availability and, therefore, phytoplankton growth. Numerical models provide unparalleled insight into these biogeochemical dynamics. Yet, to date, modelling efforts off southeastern Australia have either targeted case studies (small spatial and temporal scales) or encompassed the whole EAC System but focused on climate change effects at the mesoscale (with a spatial resolution of 1/10º). Here we couple a model of the pelagic nitrogen cycle (bio_Fennel) to a 10-year high-resolution (2.5–5 km horizontal) three-dimensional ocean model (ROMS) to resolve both regional and finer scale biogeochemical processes occurring in the EAC System. We use several statistical metrics to compare the simulated surface chlorophyll to an ocean colour dataset (Copernicus-GlobColour) for the 2003–2011 period and show that the model can reproduce the observed phytoplankton surface patterns with a domain-wide rmse of approximately 0.2 mg chla m−3 and a correlation coefficient of 0.76. This coupled configuration will provide a much-needed framework to examine phytoplankton variability in the EAC System providing insight into important ecosystem dynamics such as regional nutrient supply mechanisms and biogeochemical cycling occurring in EAC eddies.

scholarly journals A high-resolution biogeochemical model (ROMS 3.4 + bio_Fennel) of the East Australian Current system

2019 ◽  
Vol 12 (1) ◽  
pp. 441-456 ◽  
Author(s):  
Carlos Rocha ◽  
Christopher A. Edwards ◽  
Moninya Roughan ◽  
Paulina Cetina-Heredia ◽  
Colette Kerry
Keyword(s):  
Climate Change ◽  
High Resolution ◽  
Fishery Management ◽  
Numerical Models ◽  
Current System ◽  
Ecosystem Dynamics ◽  
Biogeochemical Model ◽  
East Australian Current ◽  
Surface Patterns ◽  
Insight Into

Abstract. Understanding phytoplankton dynamics is critical across a range of topics, spanning from fishery management to climate change mitigation. It is particularly interesting in the East Australian Current (EAC) system, as the region's eddy field strongly conditions nutrient availability and therefore phytoplankton growth. Numerical models provide unparalleled insight into these biogeochemical dynamics. Yet, to date, modelling efforts off southeastern Australia have either targeted case studies (small spatial and temporal scales) or encompassed the whole EAC system but focused on climate change effects at the mesoscale (with a spatial resolution of 1/10∘). Here we couple a model of the pelagic nitrogen cycle (bio_Fennel) to a 10-year high-resolution (2.5–5 km horizontal) three-dimensional ocean model (ROMS) to resolve both regional and finer-scale biogeochemical processes occurring in the EAC system. We use several statistical metrics to compare the simulated surface chlorophyll to an ocean colour dataset (Copernicus-GlobColour) for the 2003–2011 period and show that the model can reproduce the observed phytoplankton surface patterns with a domain-wide RMSE of approximately 0.2 mg Chl a m−3 and a correlation coefficient of 0.76. This coupled configuration will provide a much-needed framework to examine phytoplankton variability in the EAC system providing insight into important ecosystem dynamics such as regional nutrient supply mechanisms and biogeochemical cycling occurring in EAC eddies.

Effects on hydrodynamics and ecological costs of climate change and tidal stream energy extraction in a shelf sea

2020 ◽  
Author(s):  
Michela De Dominicis ◽  
Judith Wolf ◽  
Dina Sadykova ◽  
Beth Scott ◽  
Alexander Sadykov ◽  
...  
Keyword(s):  
Climate Change ◽  
Large Scale ◽  
Climate Scenario ◽  
Tidal Energy ◽  
Ocean Model ◽  
Future Climate ◽  
Biogeochemical Model ◽  
Energy Extraction ◽  
Shelf Sea ◽  
Tidal Stream

<p>The aim of this work is to analyse the potential impacts of tidal energy extraction on the marine environment. We wanted to put them in the broader context of the possibly greater and global ecological threat of climate change. Here, we present how very large (hypothetical) tidal stream arrays and a ''business as usual'' future climate scenario can change the hydrodynamics of a seasonally stratified shelf sea, and consequently modify ecosystem habitats and animals’ behaviour.</p><p>The Scottish Shelf Model, an unstructured grid three-dimensional ocean model, has been used to reproduce the present and the future state of the NW European continental shelf. While the marine biogeochemical model ERSEM (European Regional Seas Ecosystem Model) has been used to describe the corresponding biogeochemical conditions. Four scenarios have been modelled: present conditions and projected future climate in 2050, each with and without very large scale tidal stream arrays in Scottish Waters (UK). This allows us to evaluate the potential effect of climate change and large scale energy extraction on the hydrodynamics and biogeochemistry. We found that climate change and tidal energy extraction both act in the same direction, in terms of increasing stratification due to warming and reduced mixing, however, the effect of climate change is ten times larger. Additionally, the ecological costs and benefits of these contrasting pressures on mobile predator and prey marine species are evaluated using ecological statistical models.</p>

scholarly journals A Relocatable Ocean Modeling Platform for Downscaling to Shelf-Coastal Areas to Support Disaster Risk Reduction

2021 ◽  
Vol 8 ◽  
Author(s):  
Francesco Trotta ◽  
Ivan Federico ◽  
Nadia Pinardi ◽  
Giovanni Coppini ◽  
Salvatore Causio ◽  
...  
Keyword(s):  
High Resolution ◽  
Risk Reduction ◽  
Ocean Circulation ◽  
Disaster Risk Reduction ◽  
Prediction Models ◽  
Numerical Models ◽  
World Ocean ◽  
Disaster Risk ◽  
Ocean Model ◽  
Coastal Areas

High-impact ocean weather events and climate extremes can have devastating effects on coastal zones and small islands. Marine Disaster Risk Reduction (DRR) is a systematic approach to such events, through which the risk of disaster can be identified, assessed and reduced. This can be done by improving ocean and atmosphere prediction models, data assimilation for better initial conditions and developing an efficient and sustainable impact forecasting methodology for Early Warnings Systems. A common user request during disaster remediation actions is for high-resolution information, which can be derived from easily deployable numerical models nested into operational larger-scale ocean models. The Structured and Unstructured Relocatable Ocean Model for Forecasting (SURF) enables users to rapidly deploy a nested high-resolution numerical model into larger-scale ocean forecasts. Rapidly downscaling the currents, sea level, temperature, and salinity fields is critical in supporting emergency responses to extreme events and natural hazards in the world’s oceans. The most important requirement in a relocatable model is to ensure that the interpolation of low-resolution ocean model fields (analyses and reanalyses) and atmospheric forcing is tested for different model domains. The provision of continuous ocean circulation forecasts through the Copernicus Marine Environment Monitoring Service (CMEMS) enables this testing. High-resolution SURF ocean circulation forecasts can be provided to specific application models such as oil spill fate and transport models, search and rescue trajectory models, and ship routing models requiring knowledge of meteo-oceanographic conditions. SURF was used to downscale CMEMS circulation analyses in four world ocean regions, and the high-resolution currents it can simulate for specific applications are examined. The SURF downscaled circulation fields show that the marine current resolutions affect the quality of the application models to be used for assessing disaster risks, particularly near coastal areas where the coastline geometry must be resolved through a numerical grid, and high-frequency coastal currents must be accurately simulated.

High-resolution 3D Forecasting System for Barcelona's beaches and coastal waters

2021 ◽  
Author(s):  
María Liste Muñoz ◽  
Marc Mestres Ridge ◽  
Manuel Espino Infantes ◽  
Agustín Sánchez-Arcilla ◽  
Manuel García León ◽  
...  
Keyword(s):  
Sediment Transport ◽  
High Resolution ◽  
Coastal Waters ◽  
Numerical Models ◽  
Ocean Model ◽  
Coastal Areas ◽  
Rip Currents ◽  
The European Union ◽  
Informed Decisions ◽  
Prediction Systems

<p>The ocean is an essential part of the planet that plays a crucial role in the global life system and provides vital resources for humanity. Coastal areas are the most affected by direct pressure from human activity, and their management is very complex due to the multiple interconnected processes that occur there. To conserve and protect our coastal areas, we must observe and understand how they interact. Despite its paramount importance to society, there are fundamental gaps in coastal observing and modelling. Therefore, current forecasting systems limit our capacity to manage this narrow border between land and sea sustainably. Improved numerical models and sustained observations of our ocean are needed to make informed decisions and ensure that human-coastal interaction is sustainable and safe.</p><p>EuroSea initiative is an innovation action of the European Union entitled "Improvement and integration of the European oceans Observation and prediction systems for the sustainable use of the oceans'. EuroSea brings together the leading European players in the ocean observation and forecasting with users of oceanographic products and services and provides high-resolution coastal operational prediction systems in domains such as ports, beaches and nearby coastal waters.</p><p>In the EuroSea project framework, we present a 3D hydrodynamic tool to improve Barcelona's beaches' inner dynamics solution. We use the Coupled Ocean-Atmosphere - Wave - Sediment Transport (COAWST) Modeling System that utilizes the Model Coupling Toolkit to exchange prognostic variables between the ocean model ROMS, wave model SWAN, and the Community Sediment Transport Modeling System (CSTMS) sediment routines. As part of the system, the wave and ocean models run with nested, refined, spatial grids to provide increased resolution, scaling down to resolve nearshore wave-driven flows, all within selected regions of a larger, coarser-scale coastal modelling system.</p><p>Bathymetry was built using a combination of bathymetric data from EMODnet (European Marine Observation and Data Network), and specific high-resolution sources provided by local authorities. Copernicus products have driven these high-resolution simulations.</p><p>Results have been validated with field campaigns data, displaying preliminary agreements between model outputs and in-situ observations. The model provides results that will be used to study interactions between sea-level hazards, economic activity, and risk. These results will develop new forecast capabilities, such as erosion and flooding, rip currents, floating debris and flushing times.</p><p>Finally, we look ahead to the future of the operational prediction systems as useful tools to make informed decisions, minimize risks and improve environmental management.</p>

Multidecadal simulation of the tropical and subtropical South Atlantic Ocean with a high resolution ocean model forced by ERA-5 reanalysis data

2020 ◽  
Author(s):  
Martin Schmidt ◽  
Hadi Bordbar ◽  
Fernanda Nascimento ◽  
Claudia Frauen
Keyword(s):  
High Resolution ◽  
Wind Stress ◽  
Ocean Circulation ◽  
Reanalysis Data ◽  
Ocean Model ◽  
Ecosystem Dynamics ◽  
Boundary Current ◽  
Wind Stress Curl ◽  
Data Set ◽  
Upwelling Intensity

<p>High resolution regional ocean circulation models are needed to investigate regional ecosystem dynamics. However, these models may suffer from biases due to shortcomings in reanalysis datasets like NCEP or ERA-Interin, that have traditionally been used as atmospheric forcing. More realistic results can be achieved by replacing the reanalysed wind with scatterometer based winds. However, inconsistencies between different scatterometers like ASCAT and QuikSCAT introduce new uncertainty, which prevents a discussion of long-term trends in these models. The ERA-5 reanalysis offers a new consistent data set to force highly resolving regional ocean models. Based on such a simulation we analyse trends and anomalies in poleward currents in the Eastern Boundary Current off Southern Africa and Northern Benguela upwelling intensity due to changing wind stress and wind stress curl. Model results are validated with remote sensing as well as shipborne and mooring data. Further, variability of oxygen conditions in the Northern Benguela and the Angola Gyre oxygen minimum zone is discussed. </p>

scholarly journals Performance and results of the high-resolution biogeochemical model PELAGOS025 v1.0 within NEMO v3.4

2016 ◽  
Vol 9 (6) ◽  
pp. 2115-2128 ◽  
Author(s):  
Italo Epicoco ◽  
Silvia Mocavero ◽  
Francesca Macchia ◽  
Marcello Vichi ◽  
Tomas Lovato ◽  
...  
Keyword(s):  
High Resolution ◽  
Message Passing ◽  
Ocean Model ◽  
Parallel Architectures ◽  
Global Ocean ◽  
Biogeochemical Model ◽  
Memory Contention ◽  
On Line ◽  
Flux Model ◽  
Line Coupling

Abstract. The present work aims at evaluating the scalability performance of a high-resolution global ocean biogeochemistry model (PELAGOS025) on massive parallel architectures and the benefits in terms of the time-to-solution reduction. PELAGOS025 is an on-line coupling between the Nucleus for the European Modelling of the Ocean (NEMO) physical ocean model and the Biogeochemical Flux Model (BFM) biogeochemical model. Both the models use a parallel domain decomposition along the horizontal dimension. The parallelisation is based on the message passing paradigm. The performance analysis has been done on two parallel architectures, an IBM BlueGene/Q at ALCF (Argonne Leadership Computing Facilities) and an IBM iDataPlex with Sandy Bridge processors at the CMCC (Euro Mediterranean Center on Climate Change). The outcome of the analysis demonstrated that the lack of scalability is due to several factors such as the I/O operations, the memory contention, the load unbalancing due to the memory structure of the BFM component and, for the BlueGene/Q, the absence of a hybrid parallelisation approach.

scholarly journals On the sensitivity of plankton ecosystem models to the formulation of zooplankton grazing

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0252033
Author(s):  
Fanny Chenillat ◽  
Pascal Rivière ◽  
Mark D. Ohman
Keyword(s):  
Spatial Patterns ◽  
Current System ◽  
Ecosystem Dynamics ◽  
Biogeochemical Model ◽  
Zooplankton Grazing ◽  
Ecosystem Models ◽  
Prey Concentration ◽  
Phytoplankton Diversity ◽  
California Current System ◽  
Spatial Gradients

Model representations of plankton structure and dynamics have consequences for a broad spectrum of ocean processes. Here we focus on the representation of zooplankton and their grazing dynamics in such models. It remains unclear whether phytoplankton community composition, growth rates, and spatial patterns in plankton ecosystem models are especially sensitive to the specific means of representing zooplankton grazing. We conduct a series of numerical experiments that explicitly address this question. We focus our study on the form of the functional response to changes in prey density, including the formulation of a grazing refuge. We use a contemporary biogeochemical model based on continuum size-structured organization, including phytoplankton diversity, coupled to a physical model of the California Current System. This region is of particular interest because it exhibits strong spatial gradients. We find that small changes in grazing refuge formulation across a range of plausible functional forms drive fundamental differences in spatial patterns of plankton concentrations, species richness, pathways of grazing fluxes, and underlying seasonal cycles. An explicit grazing refuge, with refuge prey concentration dependent on grazers’ body size, using allometric scaling, is likely to provide more coherent plankton ecosystem dynamics compared to classic formulations or size-independent threshold refugia. We recommend that future plankton ecosystem models pay particular attention to the grazing formulation and implement a threshold refuge incorporating size-dependence, and we call for a new suite of experimental grazing studies.

scholarly journals Variability and Coherence of the Agulhas Undercurrent in a High-Resolution Ocean General Circulation Model

2009 ◽  
Vol 39 (10) ◽  
pp. 2417-2435 ◽  
Author(s):  
A. Biastoch ◽  
L. M. Beal ◽  
J. R. E. Lutjeharms ◽  
T. G. D. Casal
Keyword(s):  
High Resolution ◽  
General Circulation ◽  
Current System ◽  
Circulation Model ◽  
Ocean General Circulation Model ◽  
Ocean Model ◽  
Western Boundary ◽  
Boundary Current ◽  
Sensitivity Experiment ◽  
Agulhas Current

Abstract The Agulhas Current system has been analyzed in a nested high-resolution ocean model and compared to observations. The model shows good performance in the western boundary current structure and the transports off the South African coast. This includes the simulation of the northward-flowing Agulhas Undercurrent. It is demonstrated that fluctuations of the Agulhas Current and Undercurrent around 50–70 days are due to Natal pulses and Mozambique eddies propagating downstream. A sensitivity experiment that excludes those upstream perturbations significantly reduces the variability as well as the mean transport of the undercurrent. Although the model simulates undercurrents in the Mozambique Channel and east of Madagascar, there is no direct connection between those and the Agulhas Undercurrent. Virtual float releases demonstrate that topography is effectively blocking the flow toward the north.

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