FieldOutOfBoundError: How to retain particle trajectories when they leave the study area?

[Cyuan-hub]

Question

Question

Dear @erikvansebille,
I hope this message finds you well. I am currently using Parcels version 3.0.2 to conduct 3D particle simulations. However, I encountered an issue where all particles leaving the study area (with the status ErrorOutOfBounds) are deleted using particle.delete().
Instead of deleting these particles, I would like to retain their trajectory data until the end of the simulation, even after they leave the study area. Because I want is to preserve their trajectories for analysis, rather than removing them entirely.
Could you please advise how I can achieve this behavior?

Supporting code/error messages

Below is my relevant Kernel code:

def KeepInOcean(particle, fieldset, time):
    p_depth = particle.depth
    if particle.state == StatusCode.ErrorThroughSurface or particle.depth < 0.5:
        particle_ddepth = 0.5 - p_depth
        particle.state = StatusCode.Success
    elif particle.state == StatusCode.ErrorOutOfBounds:
        particle.particle_state = 33
        particle.delete()

I execute the simulation using the following code:

kernels = [AdvectionRK4_3D, Kooi_biofouling_TEOS10, KeepInOcean]
pfile = ParticleFile(outfile, pset, outputdt = timedelta(hours = hrsOutdt))
pset.execute(kernels, runtime = timedelta(days = simdays), dt = delta(seconds = secsdt), output_file = pfile )

When visualizing the results with the following code, I noticed that the trajectories of particles leaving the study area were completely removed.

import xarray as xr
import matplotlib.pyplot as plt
# Load the ParticleFile
ds = xr.open_zarr(outfile)
plt.plot(ds['lon'].T,ds['lat'].T)
plt.scatter(lons, lats)
plt.show()

Thank you very much for your time and assistance. I look forward to your guidance!

Best regards,

Cyuan

[Cyuan-hub]

After reviewing my code and setup, I found that the issue was caused by a mismatch between the particle release locations and the positions of the flow field data.