Final location

[Jallel30]

Hello everyone, I wanted to know if by saving just the last day of a simulation the particles stranded in the past days keep saved in the final file?

thanks!

[knutfrode]

The netCDF file output by OpenDrift keeps the full history (though possibly downsampled in time if output time step is larger than calculation time step). The particles stranded (or otherwise deactivated) at an earlier time, will be there, but will have status>0 after stranding (0=active). Thus "saving just the last day" is not possbile with the built-in netCDF writer.

A saved netCDF file may be imported at a later time: >>> o = opendrift.open(<filename>

[AndresSepulveda]

To clarify, if we do set the output_time_step to one day but the time_step to one hour, we will not know at what time of the day it was stranded (but the stranding location will be ok). Is this correct?

[knutfrode]

Yes, that is correct. It will be stranded at correct location (during an internal calculation time step), but you lose information about at which internal time step this happened. Though I believe this information can be derived from property age_secondswhich will be frozen after deactivation.

So, in general it is recommended to have small calculation time step so that particles do not jump far onto land. But you may still use larger output time step to save disk space and memory.

[gauteh]

Closing, seems to be solved.