Python Ocean Model (pyOM)

Introduction

A numerical Ocean Circulation Model to configure and to integrate idealized numerical simulations with python (GUI) and a standard Fortran90 frontend.

In both cases, the dynamical core of the model is written in Fortran90.

Features

• Surface pressure or implicit linear free surface formulation
• Non-hydrostatic version
• 1D domain decomposition for parallel computation

Assumptions and Approximations

• Neglecting of thermodynamic equation
• Boussinesq approximation
  • ( Volume conservation and Buoyancy perturbations in gravity term)
• Cartesian and beta-plane approximation

Resources

• Model Manual Here

• Ocean Model Source Code Here

Prerequisites and Installation

Prerequisites

1. Unix system

2. Fortran 90 compiler

3. Fortran and Python front ends NetCDF-library

Installation

1. Make a new directory where the model code should be placed. Name the directory as dir(for instance)

2. Get into the remote server thunder1 (Only for students in UHH)

ssh thunder1

3. Once you log in, find u241155 (Prof. Eden directory)

finger u241155

and copy this directory to your new directory to get src file for compiling.

cp home/zmaw/u241155/pyOM_thunder

4. Then, by different Fortran subroutines and Python methods in the model configuration

environments in specific realizations can be shown.

List of Directories

* ./for_src: Fortran subroutines used by both Fortran and Python front end

* ./py_src: Python modules and extension modules

* ./py_config: Configuration examples of Python front end

* ./for_config: Configuration examples for Fortran front end

* ./doc: contains documentation

* ./bin: contains executable of Fortran front end after successful compilation

Model Configurations

Allocating the model variables

* set_parameter :sets all important fixed model parameter

In the model setup

* set_coriolis : sets the (vertical and horizontal) Coriolis parameter.

* initial_conditions :sets the initial conditions.

* topography : set the topography.

For each time step

* boundary_conditions : set the surface boundary conditions.

* restoring_zones : set the interior sources and sinks for density.

* momentum_restoring_zones : set the interior sources and sinks for momentum.

* tracer_sources : set interior sources and sinks for the passive tracer. Also sets the surface boundary conditions.

Sample Configurations

Kelvin-Helmholtz Instability

Content Here

kelvin_helm1.py

Eady's Baroclinic Instability

Content Here

eady1.py / eady2.py

Eddy-driven zonal jets

Content Here

jets1.py

Thermohaline Circulation

Content Here

THC1.py

Southern Ocean Circulation

Content Here

acc1.py

ENSO Response

Content Here

enso1.py

Equatorial Waves

Content Here

eq_waves1.py

Rayleigh–Bénard Convection

Content Here

rayleigh.py

Isopycnal Diffusion

Content Here

isopyc_test1.py

//pyOM (Python Ocean Model)

is a numerical ocean circulation model with an easy to use python (GUI) and a standard

Fortran90 frontend. In both cases, the dynamical core of the model is written in Fortran90.

Some features are

• surface pressure or implicit linear free surface formulation
• nonhydrostatic version
• 1D domain decomposition for parallel computation

• Documentation available as pdf file

An example of the python GUI for Eady's baroclinic instability case is shown below.

Source code pyOM_1.1.tar.gz