Modelling
NIVA's Oceanography section develops a diverse range of models and types of applications that includes models describing various physical, biological, chemical or geological processes in rivers, lakes, fjords or oceans. The marine models address both pelagic and benthic processes. We also work with near field studies of flow out of discharge pipes or other more engineering based models.
A model of a marine system first of all needs to describe the physical environment. This could be a 3D model describing a lake, fjord or ocean, a 1D model resolving only the vertical dimension in a lake or a fjord basin or a 1D river model resolving only the horizontal dimension along the river. After the physical environment is established, different modules describing biological processes like plankton growth, dispersion of bacteria or sediment transport can be added.
Examples:
NIVA Fjord Model
This model focuses on describing the circulation of matter (C, N, P and S) in fjords that are partly separated from the open ocean with sills. Below sill depth in these fjord basins the vertical mixing can be very low. 3D models often fail to describe such conditions due to dubious numerical mixing. In the NIVA Fjord Model each basin is a box that only resolves the vertical dimension, and horizontal movement is not allowed for unless it is between basins. The fate of each element is followed from discharge, through phytoplankton groups, zooplankton, bacteria, detritus, mussels and to the sediments.
Contact: ans@niva.no
FVCOM
In collaboration with Akvaplan-niva, FVCOM is one of the 3D ocean circulation models used by NIVA. FVCOM (The Unstructured Grid Finite Volume Community Ocean Model) is developed at the University of Massachusetts – Dartmouth, USA. The model utilizes a flexible mesh that consists of triangles that can easily be adapted to a complex coastline.
FVCOM is currently used in the FAABulous project where the objective is to study plankton blooms in arctic fjords in a future climate. FVCOM is set up for the west coast of Svalbard.
AERSEM
Arctic-European Regional Seas Ecosystem Model (AERSEM) is a 3D ocean biogeochemical model developed by NIVA for the North Atlantic/Nordic Seas and Eurasian Arctic region. It is based on a ROMS hydrodynamic model with sea-ice module and grid/forcings adapted for the region. The ROMS physics is coupled to a biogeochemical/ecosystem model based on the ERSEM model developed by Plymouth Marine Laboratory under the Shelf Sea Biogeochemistry research programme.
The coupling was achieved using the Framework for Aquatic Biogeochemical Models (FABM) under the OASIS/ARSEC project in collaboration with PML.
Results shown here are strictly provisional and model development is ongoing at NIVA as part of the OASIS/ARSEC and OAFRAM projects.
BROM
The BROM model (Benthic RedOx Model) is a 1D vertical coupled pelagic-benthic model, considering the transport of matter by turbulence in the water column and the bottom boundary layer (BBL), molecular diffusion, bioturbation and bioirrigation in the upper sediment. This model describes the formation and decay of organic matter, the reduction and oxidation of N, C, S, Mn, Fe species, and the transformation of P and Si species. As a component of the Framework for Aquatic Biogeochemical Models (FABM), BROM comprises a set of modules (i.e., for redox chemistry, carbonate system, pollutant partitioning) that can be incorporated into other FABM family models. A basic description of how to get started with BROM-transport and FABM is available here.
BROM is currently being used in projects connected with oxygen depletion, ocean acidification, lake salinization, CCS reservoir leakage, and sediment efflux of heavy metals and radioactive substances.