pymt_roms is a package that converts bmi_roms package into a reusable, plug-and-play data component for PyMT modeling framework developed by Community Surface Dynamics Modeling System (CSDMS). This allows ROMS model datasets to be easily coupled with other datasets or models that expose a Basic Model Interface.

The current implementation supports 2D, 3D and 4D ROMS output datasets defined with geospatial and/or time dimensions (e.g., dataset defined with dimensions as [time, s_rho, eta_rho, xi_rho])

Installing pymt

Installing pymt from the conda-forge channel can be achieved by adding conda-forge to your channels with:

conda config --add channels conda-forge

Note: Before installing pymt, you may want to create a separate environment into which to install it. This can be done with,

conda create -n pymt python=3
conda activate pymt

Once the environment is activated, pymt can be installed with the following command. Please note that the `pymt_roms` requires the development version of `pymt` (e.g., v1.3.2dev0).

# install pymt stable release and dependency packages
$ conda install pymt

# update to pymt dev version
$ pip install git+http://github.com/csdms/pymt

Installing pymt_roms

To install pymt_roms, use pip

pip install pymt_roms

or conda

conda install -c conda-forge pymt_roms

Coding Example

You can learn more details about the coding example from the tutorial notebook.

import matplotlib.pyplot as plt
import numpy as np

from pymt.models import Roms

# initiate a data component
data_comp = Roms()
data_comp.initialize('config_file.yaml')

# get variable info
for var_name in data_comp.output_var_names:
    var_unit = data_comp.var_units(var_name)
    var_location = data_comp.var_location(var_name)
    var_type = data_comp.var_type(var_name)
    var_grid = data_comp.var_grid(var_name)
    var_itemsize = data_comp.var_itemsize(var_name)
    var_nbytes = data_comp.var_nbytes(var_name)

    print('variable_name: {} \nvar_unit: {} \nvar_location: {} \nvar_type: {} \nvar_grid: {} \nvar_itemsize: {}'
        '\nvar_nbytes: {} \n'. format(var_name, var_unit, var_location, var_type, var_grid, var_itemsize, var_nbytes))

# get time info
start_time = data_comp.start_time
end_time = data_comp.end_time
time_step = data_comp.time_step
time_units = data_comp.time_units
time_steps = int((end_time - start_time)/time_step) + 1

print('start_time: {} \nend_time: {} \ntime_step: {} \ntime_units: {} \ntime_steps: {}'.format(
        start_time, end_time, time_step, time_units, time_steps))

# get variable grid info
for var_name in data_comp.output_var_names:
    grid_id = data_comp.var_grid(var_name)
    grid_type = data_comp.grid_type(grid_id)
    grid_rank = data_comp.grid_ndim(grid_id)
    grid_shape = data_comp.grid_shape(grid_id)
    grid_spacing = data_comp.grid_spacing(grid_id)
    grid_origin = data_comp.grid_origin(grid_id)

    print('var_name: {} \ngrid_id: {} \ngrid_type: {} \ngrid_rank: {} \ngrid_shape: {} \ngrid_spacing: {} \ngrid_origin: {} \n'.format(
        var_name, grid_id, grid_type, grid_rank, grid_shape, grid_spacing, grid_origin))

# get variable data
data = data_comp.get_value('time-averaged salinity')
data_3D = data.reshape([40, 106, 242])

# get lon and lat data
lat = data_comp.get_value('latitude of RHO-points').reshape([106, 242])
lon = data_comp.get_value('longitude of RHO-points').reshape([106, 242])

# make a contour plot
fig = plt.figure(figsize=(10,7))
im = plt.contourf(lon, lat, data_3D[0], levels=36)
fig.colorbar(im)
plt.axis('equal')
plt.xlabel('Longitude [degree_east]')
plt.ylabel('Latitude [degree_north]')
plt.title('ROMS model data of time-averaged salinity')

Parameters

A configuration file is required to initialize an instance of the ROMS data component. This file includes the following parameters:

• filename: Path or URL (e.g., OPeNDAP data url) of the ROMS model data to open.

• download: Bool value as True or False to indicate whether to download and save the data as a netCDF file with the provided URL. The dataset will be saved in the working directory with a file name including the time information (e.g., romsdata_12032023T162045.nc)