Problem with adding wind fields to the fieldset

[ClaudiaFarris]

Hi,

I'm trying to add the wind fields to my fieldset in order to implement the windage; this is the code that I'm using:
data_current = "20180101_h-CMCC--RFVL-MFSe3r1-MED-b20200901_re-sv01.00.nc"
data_wind= "CRMA-WRF_10mwinds_Adriatic_2018010100-2018010123.nc"

filenames_current = {'U': {'lon': data_current, 'lat': data_current, 'data': data_current}, 'V': {'lon': data_current, 'lat': data_current, 'data': data_current}}
variables_current = {'U': 'u', 'V': 'v'}
dimensions_current = {'U': {'lon': 'lon', 'lat': 'lat', 'time': 'time'}, 'V': {'lon': 'lon', 'lat': 'lat', 'time': 'time'}}

filenames_wind = {'Uwind': {'lon': data_wind, 'lat': data_wind, 'data': data_wind}, 'Vwind' :{'lon': data_wind, 'lat': data_wind, 'data': data_wind}}
variables_wind = {"Uwind": "air_u", "Vwind": "air_v"}
dimensions_wind = {'Uwind': {'lon': 'lon', 'lat': 'lat', 'time': 'time'}, 'Vwind': {'lon': 'lon', 'lat': 'lat', 'time': 'time'}}

fieldset = FieldSet.from_netcdf(filenames_current, variables_current, dimensions_current)
fieldset_wind= FieldSet.from_netcdf(filenames_wind, variables_wind, dimensions_wind)

fieldset.add_field(fieldset_wind.Uwind)
fieldset.add_field(fieldset_wind.Vwind)

And this is the advection kernel that I'm using for my first tests:
def Advection2(particle, fieldset, time):
(uc1, vc1 )= fieldset.UV[time, particle.depth, particle.lat, particle.lon]
u1, v1 = fieldset.Uwind[time, particle.depth, particle.lat, particle.lon],fieldset.Vwind[time, particle.depth, particle.lat, particle.lon]
ua1 = u1+uc1
va1 = v1+vc1
particle.lon+= ua1 * particle.dt
particle.lat += va1 * particle.dt

When I run the simulation I get this warning: WARNING: ParticleSet is empty on writing as array at time 7200.

I don't know what the problem could be. I've tried to read the wind fields as currents in order to see if the problem was the lecture of the netcdf file but it has been read correctly and the particles have been advected.

Anyone has an idea how I could solve this problem?

Thank you!

[erikvansebille]

Hi @ClaudiaFarris, could it be that your wind fields don't have their units converted? See also the UnitConverter tutorial at https://nbviewer.org/github/OceanParcels/parcels/blob/master/parcels/examples/tutorial_unitconverters.ipynb