Error exists when Reader sea_water_velocity from MET-Norway

[dayeno]

Hi,

I am trying to simulate iceberg drift with Openberg Module. But at the very beginning, the input of the forcing data from MET-Norway always shows error. The script and log file are shown below. I have tried other forcing data files, but the errors shown are all related to the missing sea_water_velocity information.

### Script:

import matplotlib.pyplot as plt
import numpy as np
from opendrift.models.openberg import OpenBerg
from opendrift.readers import reader_netCDF_CF_generic
from datetime import datetime,timedelta

o = OpenBerg()

o.set_config('drift:vertical_profile', False) # use surface currents for this test

ocean_reader = reader_netCDF_CF_generic.Reader('https://thredds.met.no/thredds/dodsC/romshindcast/barents2500_2010/daily_average/2013/01/barents_avg_zdepth_20130131_m00_HC_24h.nc')
print(ocean_reader.variables)
#ocean_reader.plot(variable = 'x_sea_water_velocity')
ocean_reader.plot(variable = 'sea_water_speed')

o.add_reader(ocean_reader)

o.seed_elements(lon = 60, lat = 72, time = datetime.now(), number = 1, radius = 500, sail = 10, draft = 50, length = 90, width = 40)

o.run(steps=1)
o.plot(fast = True)

### Log file:

15:20:39 INFO opendrift.models.basemodel:2140: "Missing variables: ['x_sea_water_velocity', 'y_sea_water_velocity']", 'The simulation stopped before requested end time was reached.'

15:20:39 INFO opendrift.models.basemodel:2143: ========================
Traceback (most recent call last):
File "/home/daye/Code/OpenDrift/opendrift/opendrift/models/basemodel/init.py", line 2101, in run
raise ValueError(
ValueError: No more active or scheduled elements, quitting.

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/home/daye/Code/OpenDrift/Gallery/Test/example_openberg.py", line 43, in
o.run(steps=1)
File "/home/daye/Code/OpenDrift/opendrift/opendrift/models/basemodel/init.py", line 111, in inner
r = func(self, *args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/daye/Code/OpenDrift/opendrift/opendrift/models/basemodel/init.py", line 2147, in run
raise ValueError('Simulation stopped within '
ValueError: Simulation stopped within first timestep. "Missing variables: ['x_sea_water_velocity', 'y_sea_water_velocity']", 'The simulation stopped before requested end time was reached.'

[knutfrode]

Hi,
I recommend using loglevel=0 to get the full debug log, so that you can see what goes wrong.
But I guess it is here related to the fact that you are seeding icebergs "now", whereas this single current file covers only a very specific time (single timestep) on a specific date in 2013.

[dayeno]

Hi again,

Thanks for your quick help. The attachment is the full log file. It seems that the "x_sea_water_velocity" and "y_sea_water_velocity" are "Nan" values. According the log file, "x_sea_water_velocity" and "y_sea_water_velocity" are derived by rotating "eastward_sea_water_velocity" and "northward_sea_water_velocity". Could the error be occurring here?

I also tried many other time-period data files and they all showed the same error. Moreover, even without running Openberg, the error occurs immediately when I try to display "x_sea_water_velocity" after reading the data (Command : ocean_reader.plot(variable = 'x_sea_water_velocity')). But displaying "eastward_sea_water_velocity" works fine.

Thanks again.
logfile.txt

[knutfrode]

As you can see from the log, the reader is discarded since it is only valid for 31 Jan 2013, whereas you have seeded elements on 4th Dec 2024.

13:44:02 DEBUG   opendrift.models.basemodel.environment:498: Discarding reader (ends before simuation is finished): https://thredds.met.no/thredds/dodsC/romshindcast/barents2500_2010/daily_average/2013/01/barents_avg_zdepth_20130131_m00_HC_24h.nc

[dayeno]

Hi again,

After adjusting the time, the error related to ‘x_sea_water_velocity' still exists. Attached 'logfile_new.txt' is the new log file.
logfile_new.txt

I also tried only loading the netCDF file and then plot. When the variable is 'x_sea_water_velocity', it throws an error. The script and log file are shown below. While displaying "eastward_sea_water_velocity" works fine.

### Script:
import matplotlib.pyplot as plt
import numpy as np
from opendrift.models.openberg import OpenBerg
from opendrift.readers import reader_netCDF_CF_generic
from datetime import datetime,timedelta

ocean_reader = reader_netCDF_CF_generic.Reader('https://thredds.met.no/thredds/dodsC/romshindcast/barents2500_2010/daily_average/2013/01/barents_avg_zdepth_20130131_m00_HC_24h.nc')

print(ocean_reader.variables)
ocean_reader.plot(variable = 'x_sea_water_velocity')

### Logfile:

Assuming time step of 1 hour for https://thredds.met.no/thredds/dodsC/romshindcast/barents2500_2010/daily_average/2013/01/barents_avg_zdepth_20130131_m00_HC_24h.nc
['sea_floor_depth_below_sea_level', 'sea_binary_mask', 'sea_surface_height', 'eastward_sea_water_velocity', 'northward_sea_water_velocity', 'upward_sea_water_velocity', 'sea_water_temperature', 'sea_water_salinity', 'ocean_vertical_diffusivity', 'longitude', 'latitude', 'sea_ice_area_fraction', 'sea_ice_thickness', 'eastward_sea_ice_velocity', 'northward_sea_ice_velocity', 'x_sea_water_velocity', 'y_sea_water_velocity', 'sea_ice_x_velocity', 'sea_ice_y_velocity', 'sea_ice_speed', 'sea_water_speed']
Traceback (most recent call last):
File "/home/daye/Code/OpenDrift/Gallery/Test/Test_Case/test_2.py", line 16, in
ocean_reader.plot(variable = 'x_sea_water_velocity')
File "/home/daye/Code/OpenDrift/opendrift/opendrift/readers/basereader/init.py", line 342, in plot
data = self.get_variables(variable, time, rx, ry)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/home/daye/Code/OpenDrift/opendrift/opendrift/readers/reader_netCDF_CF_generic.py", line 552, in get_variables
lon, lat, variables[vectorpair[0]], variables[vectorpair[1]],
~~~~~~~~~^^^^^^^^^^^^^^^
KeyError: 'y_sea_water_velocity'

[knutfrode]

That file/URL is only valid for a very specific time, so it cannot be used for a simulation.
You need to use a dataset with a time coverge, e.g. an aggregate
https://thredds.met.no/thredds/dodsC/fou-hi/barents_eps_zdepth_be

And also this dataset does not cover the position you have selected. This you can read from the log.