Reader boundary

Seeding elements around the border of a ocean model domain (NorKyst800) to demonstrate autmatic transition back and forth with another model covering a larger domain (Topaz).

from datetime import datetime
import numpy as np
from opendrift.readers import reader_netCDF_CF_generic
from opendrift.models.oceandrift import OceanDrift

o = OceanDrift(loglevel=20)  # Set loglevel to 0 for debug information

# Norkyst
reader_norkyst = reader_netCDF_CF_generic.Reader('https://thredds.met.no/thredds/dodsC/fou-hi/norkystv3_800m_m00_be')

# Topaz
reader_topaz = reader_netCDF_CF_generic.Reader('https://thredds.met.no/thredds/dodsC/cmems/topaz6/dataset-topaz6-arc-15min-3km-be.ncml')

o.add_reader([reader_norkyst, reader_topaz])
o.set_config('environment:fallback:land_binary_mask', 0)
o.set_config('drift:vertical_mixing', False)
13:51:01 INFO    opendrift:569: OpenDriftSimulation initialised (version 1.14.4 / v1.14.4-9-g23fa4d2)
13:51:01 INFO    opendrift.readers:63: Opening file with xr.open_dataset
13:51:03 INFO    opendrift.readers.reader_netCDF_CF_generic:332: Detected dimensions: {'x': 'X', 'y': 'Y', 'z': 'depth', 'time': 'time'}
13:51:03 INFO    opendrift.readers.basereader:176: Variable x_sea_water_velocity will be rotated from eastward_sea_water_velocity
13:51:03 INFO    opendrift.readers.basereader:176: Variable y_sea_water_velocity will be rotated from northward_sea_water_velocity
13:51:03 INFO    opendrift.readers.basereader:176: Variable x_wind will be rotated from eastward_wind
13:51:03 INFO    opendrift.readers.basereader:176: Variable y_wind will be rotated from northward_wind
13:51:03 INFO    opendrift.readers:63: Opening file with xr.open_dataset
13:51:05 INFO    opendrift.readers.reader_netCDF_CF_generic:332: Detected dimensions: {'x': 'x', 'y': 'y', 'time': 'time'}

Seeding some particles

lons = np.linspace(5, 8, 50)
lats = np.linspace(69.8, 70.8, 50)
lons, lats = np.meshgrid(lons, lats)

Seed oil elements at defined position and time

o.seed_elements(lons, lats, radius=0, number=2500,
                time=datetime.now())
13:51:05 INFO    opendrift.models.basemodel.environment:203: Adding a global landmask from GSHHG
13:51:09 INFO    opendrift.models.basemodel.environment:227: Fallback values will be used for the following variables which have no readers:
13:51:09 INFO    opendrift.models.basemodel.environment:230:    sea_surface_wave_significant_height: 0.000000
13:51:09 INFO    opendrift.models.basemodel.environment:230:    sea_surface_wave_stokes_drift_x_velocity: 0.000000
13:51:09 INFO    opendrift.models.basemodel.environment:230:    sea_surface_wave_stokes_drift_y_velocity: 0.000000
13:51:09 INFO    opendrift.models.basemodel.environment:230:    ocean_mixed_layer_thickness: 50.000000

Running model

o.run(steps=16*4, time_step=900, time_step_output=1800)
13:51:09 INFO    opendrift:1787: Skipping environment variable ocean_vertical_diffusivity because of condition ['drift:vertical_mixing', 'is', False]
13:51:09 INFO    opendrift:1787: Skipping environment variable ocean_mixed_layer_thickness because of condition ['drift:vertical_mixing', 'is', False]
13:51:09 INFO    opendrift:1798: Storing previous values of element property lon because of condition (('general:coastline_action', 'in', ['stranding', 'previous']), 'or', ('general:seafloor_action', 'in', ['previous']))
13:51:09 INFO    opendrift:1798: Storing previous values of element property lat because of condition (('general:coastline_action', 'in', ['stranding', 'previous']), 'or', ('general:seafloor_action', 'in', ['previous']))
13:51:09 INFO    opendrift:1806: Storing previous values of environment variable sea_surface_height because of condition ['drift:vertical_advection', 'is', True]
13:51:09 INFO    opendrift:945: Using existing reader for land_binary_mask to move elements to ocean
13:51:09 INFO    opendrift:975: All points are in ocean
13:51:09 INFO    opendrift:2094: 2025-10-23 13:51:05.056875 - step 1 of 64 - 2500 active elements (0 deactivated)
13:51:14 INFO    opendrift:2094: 2025-10-23 14:06:05.056875 - step 2 of 64 - 2500 active elements (0 deactivated)
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13:51:48 INFO    opendrift:2094: 2025-10-23 21:51:05.056875 - step 33 of 64 - 2500 active elements (0 deactivated)
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13:52:14 INFO    opendrift:2094: 2025-10-24 03:36:05.056875 - step 56 of 64 - 2500 active elements (0 deactivated)
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13:52:15 INFO    opendrift:2094: 2025-10-24 04:06:05.056875 - step 58 of 64 - 2500 active elements (0 deactivated)
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13:52:22 INFO    opendrift:2094: 2025-10-24 05:21:05.056875 - step 63 of 64 - 2500 active elements (0 deactivated)
13:52:23 INFO    opendrift:2094: 2025-10-24 05:36:05.056875 - step 64 of 64 - 2500 active elements (0 deactivated)
<xarray.Dataset> Size: 7MB
Dimensions:                                   (trajectory: 2500, time: 33)
Coordinates:
  * trajectory                                (trajectory) int64 20kB 0 ... 2499
  * time                                      (time) datetime64[ns] 264B 2025...
Data variables: (12/21)
    status                                    (trajectory, time) float32 330kB ...
    moving                                    (trajectory, time) float32 330kB ...
    age_seconds                               (trajectory, time) float32 330kB ...
    origin_marker                             (trajectory, time) float32 330kB ...
    lon                                       (trajectory, time) float32 330kB ...
    lat                                       (trajectory, time) float32 330kB ...
    ...                                        ...
    upward_sea_water_velocity                 (trajectory, time) float32 330kB ...
    sea_surface_wave_significant_height       (trajectory, time) float32 330kB ...
    sea_surface_wave_stokes_drift_x_velocity  (trajectory, time) float32 330kB ...
    sea_surface_wave_stokes_drift_y_velocity  (trajectory, time) float32 330kB ...
    sea_floor_depth_below_sea_level           (trajectory, time) float32 330kB ...
    land_binary_mask                          (trajectory, time) float32 330kB ...
Attributes: (12/119)
    Conventions:                                                           CF...
    standard_name_vocabulary:                                              CF...
    featureType:                                                           tr...
    title:                                                                 Op...
    summary:                                                               Ou...
    keywords:                                                              tr...
    ...                                                                    ...
    geospatial_lon_units:                                                  de...
    geospatial_lon_resolution:                                             point
    runtime:                                                               0:...
    geospatial_vertical_min:                                               0.0
    geospatial_vertical_max:                                               0.0
    geospatial_vertical_positive:                                          up


Print and plot results

print(o)
o.animation(fast=True)
===========================
--------------------
Reader performance:
--------------------
https://thredds.met.no/thredds/dodsC/fou-hi/norkystv3_800m_m00_be
 0:00:30.3  total
 0:00:00.0  preparing
 0:00:29.9  reading
 0:00:00.4  interpolation
 0:00:00.0  interpolation_time
 0:00:00.4  rotating vectors
 0:00:00.0  masking
--------------------
https://thredds.met.no/thredds/dodsC/cmems/topaz6/dataset-topaz6-arc-15min-3km-be.ncml
 0:00:41.7  total
 0:00:00.0  preparing
 0:00:41.5  reading
 0:00:00.0  interpolation
 0:00:00.0  interpolation_time
 0:00:00.1  rotating vectors
 0:00:00.0  masking
--------------------
global_landmask
 0:00:00.0  total
 0:00:00.0  preparing
 0:00:00.0  reading
 0:00:00.0  masking
--------------------
Performance:
 1:22.6 total time
    8.5 configuration
    0.0 preparing main loop
      0.0 moving elements to ocean
 1:14.0 main loop
      0.2 updating elements
    0.0 cleaning up
--------------------
===========================
Model:  OceanDrift     (OpenDrift version 1.14.4)
        2500 active Lagrangian3DArray particles  (0 deactivated, 0 scheduled)
-------------------
Environment variables:
  -----
  sea_floor_depth_below_sea_level
  sea_surface_height
  x_sea_water_velocity
  y_sea_water_velocity
     1) https://thredds.met.no/thredds/dodsC/fou-hi/norkystv3_800m_m00_be
     2) https://thredds.met.no/thredds/dodsC/cmems/topaz6/dataset-topaz6-arc-15min-3km-be.ncml
  -----
  upward_sea_water_velocity
  x_wind
  y_wind
     1) https://thredds.met.no/thredds/dodsC/fou-hi/norkystv3_800m_m00_be
  -----
  land_binary_mask
     1) global_landmask
  -----
Readers not added for the following variables:
  sea_surface_wave_significant_height
  sea_surface_wave_stokes_drift_x_velocity
  sea_surface_wave_stokes_drift_y_velocity

Discarded readers:

Time:
        Start: 2025-10-23 13:51:05.056875 UTC
        Present: 2025-10-24 05:51:05.056875 UTC
        Calculation steps: 64 * 0:15:00 - total time: 16:00:00
        Output steps: 33 * 0:30:00
===========================

13:52:24 WARNING opendrift:2453: Plotting fast. This will make your plots less accurate.
13:52:25 INFO    opendrift:4623: Saving animation to /root/project/docs/source/gallery/animations/example_reader_boundary_0.gif...
13:52:57 INFO    opendrift:3064: Time to make animation: 0:00:33.386997
../_images/example_reader_boundary_0.gif
o.plot(fast=True)
OpenDrift - OceanDrift 2025-10-23 13:51 to 2025-10-24 05:51 UTC (33 steps)
13:52:57 WARNING opendrift:2453: Plotting fast. This will make your plots less accurate.

(<GeoAxes: title={'center': 'OpenDrift - OceanDrift\n2025-10-23 13:51 to 2025-10-24 05:51 UTC (33 steps)'}>, <Figure size 946.294x1100 with 1 Axes>)

Total running time of the script: (2 minutes 12.188 seconds)

Gallery generated by Sphinx-Gallery