Note
Go to the end to download the full example code.
Convolve input
Decreasing the spatial resolution of fields from a reader by convolution. This may improve accuracy, see: https://doi.org/10.1016/j.rse.2019.01.001
from datetime import datetime, timedelta
import matplotlib.pyplot as plt
from opendrift import test_data_folder as tdf
from opendrift.readers import reader_netCDF_CF_generic
from opendrift.models.oceandrift import OceanDrift
lon = 4.9; lat = 60.0
o = OceanDrift(loglevel=20)
reader_norkyst = reader_netCDF_CF_generic.Reader(tdf + '16Nov2015_NorKyst_z_surface/norkyst800_subset_16Nov2015.nc')
time = reader_norkyst.start_time
o.add_reader([reader_norkyst])
o.seed_elements(lon, lat, radius=1000, number=1000, time=time)
o.run(steps=20)
09:36:23 INFO opendrift:507: OpenDriftSimulation initialised (version 1.14.2 / v1.14.2-21-g950aeec)
09:36:23 INFO opendrift.readers:61: Opening file with xr.open_dataset
09:36:24 INFO opendrift.readers.reader_netCDF_CF_generic:332: Detected dimensions: {'x': 'X', 'y': 'Y', 'z': 'depth', 'time': 'time'}
09:36:24 INFO opendrift.models.basemodel.environment:206: Adding a global landmask from GSHHG
09:36:28 INFO opendrift.models.basemodel.environment:229: Fallback values will be used for the following variables which have no readers:
09:36:28 INFO opendrift.models.basemodel.environment:232: sea_surface_height: 0.000000
09:36:28 INFO opendrift.models.basemodel.environment:232: x_wind: 0.000000
09:36:28 INFO opendrift.models.basemodel.environment:232: y_wind: 0.000000
09:36:28 INFO opendrift.models.basemodel.environment:232: upward_sea_water_velocity: 0.000000
09:36:28 INFO opendrift.models.basemodel.environment:232: ocean_vertical_diffusivity: 0.000000
09:36:28 INFO opendrift.models.basemodel.environment:232: sea_surface_wave_significant_height: 0.000000
09:36:28 INFO opendrift.models.basemodel.environment:232: sea_surface_wave_stokes_drift_x_velocity: 0.000000
09:36:28 INFO opendrift.models.basemodel.environment:232: sea_surface_wave_stokes_drift_y_velocity: 0.000000
09:36:28 INFO opendrift.models.basemodel.environment:232: sea_surface_wave_period_at_variance_spectral_density_maximum: 0.000000
09:36:28 INFO opendrift.models.basemodel.environment:232: sea_surface_wave_mean_period_from_variance_spectral_density_second_frequency_moment: 0.000000
09:36:28 INFO opendrift.models.basemodel.environment:232: sea_surface_swell_wave_to_direction: 0.000000
09:36:28 INFO opendrift.models.basemodel.environment:232: sea_surface_swell_wave_peak_period_from_variance_spectral_density: 0.000000
09:36:28 INFO opendrift.models.basemodel.environment:232: sea_surface_swell_wave_significant_height: 0.000000
09:36:28 INFO opendrift.models.basemodel.environment:232: sea_surface_wind_wave_to_direction: 0.000000
09:36:28 INFO opendrift.models.basemodel.environment:232: sea_surface_wind_wave_mean_period: 0.000000
09:36:28 INFO opendrift.models.basemodel.environment:232: sea_surface_wind_wave_significant_height: 0.000000
09:36:28 INFO opendrift.models.basemodel.environment:232: surface_downward_x_stress: 0.000000
09:36:28 INFO opendrift.models.basemodel.environment:232: surface_downward_y_stress: 0.000000
09:36:28 INFO opendrift.models.basemodel.environment:232: turbulent_kinetic_energy: 0.000000
09:36:28 INFO opendrift.models.basemodel.environment:232: turbulent_generic_length_scale: 0.000000
09:36:28 INFO opendrift.models.basemodel.environment:232: ocean_mixed_layer_thickness: 50.000000
09:36:28 INFO opendrift.models.basemodel.environment:232: sea_floor_depth_below_sea_level: 10000.000000
09:36:28 INFO opendrift:911: Using existing reader for land_binary_mask
09:36:28 INFO opendrift:940: All points are in ocean
09:36:28 INFO opendrift:2102: 2015-11-16 00:00:00 - step 1 of 20 - 1000 active elements (0 deactivated)
09:36:28 INFO opendrift:2102: 2015-11-16 01:00:00 - step 2 of 20 - 1000 active elements (0 deactivated)
09:36:28 INFO opendrift:2102: 2015-11-16 02:00:00 - step 3 of 20 - 1000 active elements (0 deactivated)
09:36:28 INFO opendrift:2102: 2015-11-16 03:00:00 - step 4 of 20 - 1000 active elements (0 deactivated)
09:36:28 INFO opendrift:2102: 2015-11-16 04:00:00 - step 5 of 20 - 1000 active elements (0 deactivated)
09:36:28 INFO opendrift:2102: 2015-11-16 05:00:00 - step 6 of 20 - 1000 active elements (0 deactivated)
09:36:28 INFO opendrift:2102: 2015-11-16 06:00:00 - step 7 of 20 - 1000 active elements (0 deactivated)
09:36:28 INFO opendrift:2102: 2015-11-16 07:00:00 - step 8 of 20 - 1000 active elements (0 deactivated)
09:36:28 INFO opendrift:2102: 2015-11-16 08:00:00 - step 9 of 20 - 1000 active elements (0 deactivated)
09:36:28 INFO opendrift:2102: 2015-11-16 09:00:00 - step 10 of 20 - 1000 active elements (0 deactivated)
09:36:28 INFO opendrift:2102: 2015-11-16 10:00:00 - step 11 of 20 - 1000 active elements (0 deactivated)
09:36:28 INFO opendrift:2102: 2015-11-16 11:00:00 - step 12 of 20 - 1000 active elements (0 deactivated)
09:36:28 INFO opendrift:2102: 2015-11-16 12:00:00 - step 13 of 20 - 1000 active elements (0 deactivated)
09:36:29 INFO opendrift:2102: 2015-11-16 13:00:00 - step 14 of 20 - 1000 active elements (0 deactivated)
09:36:29 INFO opendrift:2102: 2015-11-16 14:00:00 - step 15 of 20 - 1000 active elements (0 deactivated)
09:36:29 INFO opendrift:2102: 2015-11-16 15:00:00 - step 16 of 20 - 1000 active elements (0 deactivated)
09:36:29 INFO opendrift:2102: 2015-11-16 16:00:00 - step 17 of 20 - 1000 active elements (0 deactivated)
09:36:29 INFO opendrift:2102: 2015-11-16 17:00:00 - step 18 of 20 - 1000 active elements (0 deactivated)
09:36:29 INFO opendrift:2102: 2015-11-16 18:00:00 - step 19 of 20 - 1000 active elements (0 deactivated)
09:36:29 INFO opendrift:2102: 2015-11-16 19:00:00 - step 20 of 20 - 1000 active elements (0 deactivated)
Store final field of x-component of current
original_current = reader_norkyst.var_block_after[list(reader_norkyst.var_block_after.keys())[0]].data_dict['x_sea_water_velocity'].copy()
For the second run, the NorKyst currents are convolved with a kernel, effectively lowering the spatial resolution. <reader>.set_convolution_kernel may also be given as an array (kernel) directly
N = 10 # Convolusion kernel size
reader_norkyst.set_convolution_kernel(N) # Using convolution kernel for second run
o2 = OceanDrift(loglevel=20)
o2.add_reader([reader_norkyst])
o2.seed_elements(lon, lat, radius=1000, number=1000, time=time)
o2.run(steps=20)
09:36:32 INFO opendrift:507: OpenDriftSimulation initialised (version 1.14.2 / v1.14.2-21-g950aeec)
09:36:32 INFO opendrift.models.basemodel.environment:206: Adding a global landmask from GSHHG
09:36:32 INFO opendrift.models.basemodel.environment:229: Fallback values will be used for the following variables which have no readers:
09:36:32 INFO opendrift.models.basemodel.environment:232: sea_surface_height: 0.000000
09:36:32 INFO opendrift.models.basemodel.environment:232: x_wind: 0.000000
09:36:32 INFO opendrift.models.basemodel.environment:232: y_wind: 0.000000
09:36:32 INFO opendrift.models.basemodel.environment:232: upward_sea_water_velocity: 0.000000
09:36:32 INFO opendrift.models.basemodel.environment:232: ocean_vertical_diffusivity: 0.000000
09:36:32 INFO opendrift.models.basemodel.environment:232: sea_surface_wave_significant_height: 0.000000
09:36:32 INFO opendrift.models.basemodel.environment:232: sea_surface_wave_stokes_drift_x_velocity: 0.000000
09:36:32 INFO opendrift.models.basemodel.environment:232: sea_surface_wave_stokes_drift_y_velocity: 0.000000
09:36:32 INFO opendrift.models.basemodel.environment:232: sea_surface_wave_period_at_variance_spectral_density_maximum: 0.000000
09:36:32 INFO opendrift.models.basemodel.environment:232: sea_surface_wave_mean_period_from_variance_spectral_density_second_frequency_moment: 0.000000
09:36:32 INFO opendrift.models.basemodel.environment:232: sea_surface_swell_wave_to_direction: 0.000000
09:36:32 INFO opendrift.models.basemodel.environment:232: sea_surface_swell_wave_peak_period_from_variance_spectral_density: 0.000000
09:36:32 INFO opendrift.models.basemodel.environment:232: sea_surface_swell_wave_significant_height: 0.000000
09:36:32 INFO opendrift.models.basemodel.environment:232: sea_surface_wind_wave_to_direction: 0.000000
09:36:32 INFO opendrift.models.basemodel.environment:232: sea_surface_wind_wave_mean_period: 0.000000
09:36:32 INFO opendrift.models.basemodel.environment:232: sea_surface_wind_wave_significant_height: 0.000000
09:36:32 INFO opendrift.models.basemodel.environment:232: surface_downward_x_stress: 0.000000
09:36:32 INFO opendrift.models.basemodel.environment:232: surface_downward_y_stress: 0.000000
09:36:32 INFO opendrift.models.basemodel.environment:232: turbulent_kinetic_energy: 0.000000
09:36:32 INFO opendrift.models.basemodel.environment:232: turbulent_generic_length_scale: 0.000000
09:36:32 INFO opendrift.models.basemodel.environment:232: ocean_mixed_layer_thickness: 50.000000
09:36:32 INFO opendrift.models.basemodel.environment:232: sea_floor_depth_below_sea_level: 10000.000000
09:36:32 INFO opendrift:911: Using existing reader for land_binary_mask
09:36:32 INFO opendrift:940: All points are in ocean
09:36:32 INFO opendrift:2102: 2015-11-16 00:00:00 - step 1 of 20 - 1000 active elements (0 deactivated)
09:36:32 INFO opendrift:2102: 2015-11-16 01:00:00 - step 2 of 20 - 1000 active elements (0 deactivated)
09:36:32 INFO opendrift:2102: 2015-11-16 02:00:00 - step 3 of 20 - 1000 active elements (0 deactivated)
09:36:32 INFO opendrift:2102: 2015-11-16 03:00:00 - step 4 of 20 - 1000 active elements (0 deactivated)
09:36:32 INFO opendrift:2102: 2015-11-16 04:00:00 - step 5 of 20 - 1000 active elements (0 deactivated)
09:36:33 INFO opendrift:2102: 2015-11-16 05:00:00 - step 6 of 20 - 1000 active elements (0 deactivated)
09:36:33 INFO opendrift:2102: 2015-11-16 06:00:00 - step 7 of 20 - 1000 active elements (0 deactivated)
09:36:33 INFO opendrift:2102: 2015-11-16 07:00:00 - step 8 of 20 - 1000 active elements (0 deactivated)
09:36:33 INFO opendrift:2102: 2015-11-16 08:00:00 - step 9 of 20 - 1000 active elements (0 deactivated)
09:36:33 INFO opendrift:2102: 2015-11-16 09:00:00 - step 10 of 20 - 1000 active elements (0 deactivated)
09:36:33 INFO opendrift:2102: 2015-11-16 10:00:00 - step 11 of 20 - 1000 active elements (0 deactivated)
09:36:33 INFO opendrift:2102: 2015-11-16 11:00:00 - step 12 of 20 - 1000 active elements (0 deactivated)
09:36:33 INFO opendrift:2102: 2015-11-16 12:00:00 - step 13 of 20 - 1000 active elements (0 deactivated)
09:36:33 INFO opendrift:2102: 2015-11-16 13:00:00 - step 14 of 20 - 1000 active elements (0 deactivated)
09:36:33 INFO opendrift:2102: 2015-11-16 14:00:00 - step 15 of 20 - 1000 active elements (0 deactivated)
09:36:33 INFO opendrift:2102: 2015-11-16 15:00:00 - step 16 of 20 - 1000 active elements (0 deactivated)
09:36:33 INFO opendrift:2102: 2015-11-16 16:00:00 - step 17 of 20 - 999 active elements (1 deactivated)
09:36:33 INFO opendrift:2102: 2015-11-16 17:00:00 - step 18 of 20 - 999 active elements (1 deactivated)
09:36:33 INFO opendrift:2102: 2015-11-16 18:00:00 - step 19 of 20 - 999 active elements (1 deactivated)
09:36:33 INFO opendrift:2102: 2015-11-16 19:00:00 - step 20 of 20 - 999 active elements (1 deactivated)
Store final field of x-component of (convolved) current
convolved_current = reader_norkyst.var_block_after[
"['x_sea_water_velocity', 'y_sea_water_velocity']"].data_dict['x_sea_water_velocity']
plt.subplot(2,1,1)
plt.imshow(original_current, interpolation='nearest')
plt.title('Original current field (x-component)')
clim = plt.gci().get_clim()
plt.colorbar()
plt.subplot(2,1,2)
plt.imshow(convolved_current, interpolation='nearest')
plt.clim(clim) # Make sure plots are comparable
plt.colorbar()
plt.title('Final, convolved current field (x-component)')
plt.show()
Print and plot results, with convolved currents as background
print(o)
o.animation(compare=o2, fast=True, legend=[
'Original currents', 'Current convoled with kernel of size %s' % N],
background=['x_sea_water_velocity', 'y_sea_water_velocity'])
===========================
--------------------
Reader performance:
--------------------
/root/project/tests/test_data/16Nov2015_NorKyst_z_surface/norkyst800_subset_16Nov2015.nc
0:00:00.2 total
0:00:00.0 preparing
0:00:00.2 reading
0:00:00.0 interpolation
0:00:00.0 interpolation_time
0:00:00.0 rotating vectors
0:00:00.0 masking
--------------------
global_landmask
0:00:01.6 total
0:00:00.0 preparing
0:00:01.6 reading
0:00:00.0 masking
--------------------
Performance:
9.1 total time
5.0 configuration
0.0 preparing main loop
0.0 moving elements to ocean
2.4 main loop
0.0 updating elements
1.6 cleaning up
--------------------
===========================
Model: OceanDrift (OpenDrift version 1.14.2)
938 active Lagrangian3DArray particles (62 deactivated, 0 scheduled)
-------------------
Environment variables:
-----
x_sea_water_velocity
y_sea_water_velocity
1) /root/project/tests/test_data/16Nov2015_NorKyst_z_surface/norkyst800_subset_16Nov2015.nc
-----
land_binary_mask
1) global_landmask
-----
Readers not added for the following variables:
ocean_mixed_layer_thickness
ocean_vertical_diffusivity
sea_floor_depth_below_sea_level
sea_surface_height
sea_surface_swell_wave_peak_period_from_variance_spectral_density
sea_surface_swell_wave_significant_height
sea_surface_swell_wave_to_direction
sea_surface_wave_mean_period_from_variance_spectral_density_second_frequency_moment
sea_surface_wave_period_at_variance_spectral_density_maximum
sea_surface_wave_significant_height
sea_surface_wave_stokes_drift_x_velocity
sea_surface_wave_stokes_drift_y_velocity
sea_surface_wind_wave_mean_period
sea_surface_wind_wave_significant_height
sea_surface_wind_wave_to_direction
surface_downward_x_stress
surface_downward_y_stress
turbulent_generic_length_scale
turbulent_kinetic_energy
upward_sea_water_velocity
x_wind
y_wind
Discarded readers:
Time:
Start: 2015-11-16 00:00:00 UTC
Present: 2015-11-16 20:00:00 UTC
Calculation steps: 20 * 1:00:00 - total time: 20:00:00
Output steps: 21 * 1:00:00
===========================
09:36:34 WARNING opendrift:2459: Plotting fast. This will make your plots less accurate.
09:36:58 INFO opendrift:4609: Saving animation to /root/project/docs/source/gallery/animations/example_convolve_input_0.gif...
09:38:33 INFO opendrift:3062: Time to make animation: 0:01:58.792527
o.plot(fast=True)
09:38:33 WARNING opendrift:2459: Plotting fast. This will make your plots less accurate.
(<GeoAxes: title={'center': 'OpenDrift - OceanDrift\n2015-11-16 00:00 to 2015-11-16 20:00 UTC (21 steps)'}>, <Figure size 705.673x1100 with 1 Axes>)
Total running time of the script: (2 minutes 21.769 seconds)