Merge pull request #1343 from knutfrode/dev

Updated example to illustrate coastline interaction

examples/example_coastline_options.py

@@ -5,34 +5,89 @@
 
 Example to illustrate stranding options using an artificial
 east-west oscillating current field
-Knut-Frode Dagestad, Feb 2017
 """
 
-from datetime import datetime
+from datetime import datetime, timedelta
 from opendrift.readers import reader_oscillating
 from opendrift.models.oceandrift import OceanDrift
+duration = timedelta(hours=36)
+time_step = timedelta(hours=.5)
+number = 500
 
-o = OceanDrift(loglevel=50)  # Set loglevel to 0 for debug information
-
+# Oscillating east-west current to illustrate stranding options
 reader_osc = reader_oscillating.Reader('x_sea_water_velocity', amplitude=1,
                                        zero_time=datetime.utcnow())
-o.add_reader([reader_osc])  # Oscillating east-west current component
 
-o.set_config('environment:fallback:y_sea_water_velocity', .2)  # Adding northwards drift
+#%%
+# Coastline option "stranding"
+# ============================
+#
+# Note that particles are "jumping" a distance onto land, depending on calculation timestep
+o = OceanDrift(loglevel=50)
+o.add_reader([reader_osc])
+o.set_config('environment:fallback:y_sea_water_velocity', .2)
+o.set_config('general:coastline_action', 'stranding')
+o.seed_elements(lon=12.2, lat=67.7, radius=5000, number=number, time=reader_osc.zero_time)
+o.run(duration=duration, time_step=time_step)
+print(f'Calculation time: {o.timing["total time"]}')
+o.animation()
 
 #%%
-# Try different options: 'previous', 'stranding', 'none'
-o.set_config('general:coastline_action', 'previous')
+# .. image:: /gallery/animations/example_coastline_options_0.gif
 
-o.seed_elements(lon=12.2, lat=67.7, radius=5000, number=25, time=reader_osc.zero_time)
+#%%
+# Coastline option "stranding" with higher precision
+# ==================================================
+#
+# by setting config "general:coastline_approximation_precision" to desired accuracy in degrees.
+# Note that with a (too) large compuation time step, particles may still "jump" over islands.
+# An alternative to avoid this possibility is to use a smaller timestep for the simulation, though at a larger computational cost.
+o = OceanDrift(loglevel=50)
+o.add_reader([reader_osc])
+o.set_config('environment:fallback:y_sea_water_velocity', .2)
+o.set_config('general:coastline_action', 'stranding')
+o.set_config('general:coastline_approximation_precision', .001)  # approx 100m
+o.seed_elements(lon=12.2, lat=67.7, radius=5000, number=number, time=reader_osc.zero_time)
+o.run(duration=duration, time_step=time_step)
+print(f'Calculation time: {o.timing["total time"]}')
+o.animation()
 
-o.run(steps=36*4, time_step=900, time_step_output=1800)
+#%%
+# .. image:: /gallery/animations/example_coastline_options_1.gif
+
+#%
+# Coastline option "previous"
+# ===========================
+#
+# Particles hitting land are moved back to last position in water,
+# and may move offshore if currents/winds/forcing changes direction.
+# Here we see that several particles are jumping over small island.
+# Reducing timestep to e.g. 15 minutes will reduce this problem.
+o = OceanDrift(loglevel=50)
+o.add_reader([reader_osc])
+o.set_config('environment:fallback:y_sea_water_velocity', .2)
+o.set_config('general:coastline_action', 'previous')
+o.seed_elements(lon=12.2, lat=67.7, radius=5000, number=number, time=reader_osc.zero_time)
+o.run(duration=duration, time_step=time_step)
+print(f'Calculation time: {o.timing["total time"]}')
+o.animation()
 
 #%%
-# Print and plot results
-print(o)
+# .. image:: /gallery/animations/example_coastline_options_2.gif
+
+#%
+# Coastline option "none"
+# =======================
+#
+# No interaction with land, as used by e.g. WindBlow model (atmospheric drift) 
+o = OceanDrift(loglevel=50)
+o.add_reader([reader_osc])
+o.set_config('environment:fallback:y_sea_water_velocity', .2)
+o.set_config('general:coastline_action', 'none')
+o.seed_elements(lon=12.2, lat=67.7, radius=5000, number=number, time=reader_osc.zero_time)
+o.run(duration=duration, time_step=time_step)
+print(f'Calculation time: {o.timing["total time"]}')
 o.animation()
-o.plot()
 
 #%%
-# .. image:: /gallery/animations/example_coastline_options_0.gif
+# .. image:: /gallery/animations/example_coastline_options_3.gif

examples/example_fjord.py

@@ -1,7 +1,7 @@
 #!/usr/bin/env python
 """
 Fjord
-==================================
+=====
 """
 
 from datetime import timedelta
@@ -40,4 +40,3 @@
 # .. image:: /gallery/animations/example_fjord_0.gif
 
 o.plot()
-

examples/example_leeway_backtrack.py → examples/example_long_leeway_backtrack.py

@@ -40,6 +40,8 @@
 # Define domain of possible origin
 lons = np.arange(3.4, 5, .1/20)
 lats = np.arange(59.7, 60.8, .05/20)
+#lons = lons[0::2]  # using every second, due to memory limitation on CircleCI
+#lats = lats[0::2]
 corners = [lons[0], lons[-1], lats[0], lats[-1]]
 lons, lats = np.meshgrid(lons, lats)
 
@@ -53,15 +55,16 @@
 density_backwards = density_backwards.where(density_backwards>0)
 density_backwards = density_backwards/density_backwards.sum()*100
 vmax = density_backwards.max()
-o.plot(background=density_backwards, clabel='Probability of origin [%]', text=text, corners=corners, fast=True, markersize=.5, lalpha=.02, vmin=0, vmax=vmax)
+o.plot(background=density_backwards, clabel='Probability of origin [%]', text=text, corners=corners,
+       fast=True, markersize=.5, lalpha=.02, vmin=0, vmax=vmax)
 os.remove(outfile)
 
 #%%
 # Simulating then forwards, starting at a uniform grid 24 hours earlier (440 x 320 = 140800 elements at ~500m separation)
 o = Leeway(loglevel=50)
 o.add_reader([reader_norkyst, reader_arome])
 o.seed_elements(lon=lons, lat=lats, radius=0,
-                 time=start_time, object_type=object_type)
+                time=start_time, object_type=object_type)
 o.run(duration=duration, time_step=900, time_step_output=3600, outfile=outfile)
 print(o)
 
@@ -78,16 +81,20 @@
 hit_start_lats = lat[hits, 0]
 o_hit = opendrift.open(outfile, elements=hits)
 
-o.animation(compare=o_hit, legend=['Elements not hitting target', 'Elements hitting target'], fast=True, corners=corners, text=text)
+o.animation(compare=o_hit, legend=['Elements not hitting target', 'Elements hitting target'],
+            fast=True, corners=corners, text=text)
 
 #%%
 # .. image:: /gallery/animations/example_leeway_backtrack_0.gif
 
-o.plot(compare=o_hit, legend=['Elements not hitting target', 'Elements hitting target'], show_elements=False, fast=True, corners=corners, text=text)
+o.plot(compare=o_hit, legend=['Elements not hitting target', 'Elements hitting target'],
+       show_elements=False, fast=True, corners=corners, text=text)
 
 #%%
 # Plot the initial density of elements that actually hit the target after 24 hours. To be compared with the density figure from backwards simulation (see top)
 of = opendrift.open_xarray(outfile, elements=hits)
 density_forwards = of.get_histogram(pixelsize_m=5000).isel(time=0).isel(origin_marker=0)
 density_forwards = density_forwards.where(density_forwards>0)
-o_hit.plot(background=density_forwards/density_forwards.sum()*100, clabel='Probability of origin [%]', text=text, corners=corners, fast=True, markersize=.5, lalpha=.02, vmin=0, vmax=vmax)
+ratio = density_forwards/density_forwards.sum()*100
+o_hit.plot(background=ratio, clabel='Probability of origin [%]', text=text, corners=corners,
+           fast=True, markersize=.5, lalpha=.02, vmin=0, vmax=vmax)

examples/example_openberg_new.py → examples/example_openberg.py

@@ -1,7 +1,7 @@
 #!/usr/bin/env python
 """
-Icebergs (openberg)
-====================
+Icebergs (OpenBerg module)
+==========================
 """
 
 from opendrift.models.openberg import OpenBerg

examples/example_wind_measurements.py

@@ -1,7 +1,7 @@
 #!/usr/bin/env python
 """
 Using wind measurements
-===============
+=======================
 """
 
 from datetime import datetime, timedelta, date

history.rst

@@ -1,8 +1,13 @@
 History
 =======
 
+Next release
+------------
+* New feature by TheSylex to move stranded particles closer to the actual coastline with a precision given by config setting `general:coastline_approximation_precision` in unit of degrees (1deg approx 111 km)
+* Major updates to OpenBerg iceberg drift model (Achref Othmani, Lenny Hucher)
+
 2024-06-27 / Release v1.11.10
-----------------------------
+-----------------------------
 * Using now standard env variable names COPERNICUSMARINE_SERVICE_USERNAME and COPERNICUSMARINE_SERVICE_PASSWORD for reader_copernicus. Env variable COPERNICUSMARINE_CACHE_DIRECTORY can be set to empty string to disable caching.
 
 2024-06-27 / Release v1.11.9
@@ -11,6 +16,7 @@ History
 * Hack in generic reader to make sure wind from ECMWF files is at 10m height
 
 * Raising now error if all elements are seeded on land
+
 2024-06-26 / Release v1.11.8
 ----------------------------
 * Raising now error if all elements are seeded on land

opendrift/models/leeway.py

@@ -234,11 +234,8 @@ def __init__(self, d=None, *args, **kwargs):
             'processes:capsizing': {
                 'type': 'bool',
                 'default': False,
-                'min': 0,
-                'max': 1,
                 'description':
                 'If True, elements can be capsized when wind exceeds threshold given by config item capsize:wind_threshold',
-                'units': 'fraction',
                 'level': CONFIG_LEVEL_BASIC
             },
              'capsizing:leeway_fraction': {