The complete list of available tools can be found here.
Mesh refinement (AGRIF)
Online grid refinement is mad
This software allows for the seamless two-way coupling of nested sub-models within the NEMO framework (as long as these are defined on subsets of the original root grid). An arbitrary integer ratio of the root horizontal and time resolution has to be chosen which should not exceed 5 to guaranty proper coupling. If needed, successive embedding can be used to refine the solution even further.
A simple text-file describing the overall grid hierarchy has to be defined, the user is still free to assign specific namelist parameters, or forcing files to each subset, as is done for the root model. A specific tool to ensure proper geometric matching of sub-domains is available in the pre-processing package.
AGRIF is fully compatible with the whole NEMO platform : the ocean dynamics, the sea-ice and the passive tracer/biogeochemical (TOP/PISCES) components. Grid adaptivity (i.e. the capability to have moving nests according to a time-varying criterion) is potentially handled by the library, but not allowed yet.
Interfaces with observations
The observational data interface in NEMO includes three modules:
- OBS for the observation operator.
- ASM for the application of increments and model bias correction (based on the assimilation increments).
- TAM the tangent linear and adjoint model (in release 3.4 only).
Inputs-Outputs server and Coupler
The NEMO framework includes build-in interfaces for:
- input and output (I/O) using the XIOS software.
- coupling with other components of the Earth System using the OASIS software.
Inputs and outputs : XIOS
XIOS addresses the challenges related to very large volumes of data requested and produced by the model. In particular, XIOS:
- increases the flexibility of I/O management and data definition. The user can externalize the data flow description from the code through the use of XML files. This means that workflow and output definition can be changed without recompiling the NEMO code.
- improves I/O performance through dedicated parallel and asynchronous servers which allows for the overlap of I/O and computation. It is possible to obtain a single output file even with many NEMO processes (when using MPI for example).
- integrates internal and parallel post-processing performed ‘in-situ’ though the workflow described in the XML file as a full graph of parallel tasks.
Coupling interface: OASIS
The NEMO framework allows for coupling with other components of the Earth System through the OASIS coupler.
OASIS ensures cross-component communications through the setup of a parameter file where the characteristics of coupling for each exchanged quantities, such as ID, coupling frequency, and interpolation are defined.
NEMO also provides an interface for OASIS-MCT, which allows for all transformations to be performed in parallel on the set of source or target component processes and all coupling exchanges to be executed in parallel directly between the component processes.