Current interpolation with different landmasks

[SamTFredriksson]

Hi,
I´m looking into how to set the landmask the most appropriate way and how the interpolation will work if using the default GSHHG landmask looking into https://opendrift.github.io/gallery/example_model_landmask.html

In the enclosed plot of the southern part of Skagerrak I have two areas of interest with different questions with ‘coastline_action’ of ‘previous’.

In the orange box I have sketched two green particles, one full and one striped. I´ve also sketched two possible currents in red and yellow as can be seen with quite different, however, possible direction. The full particle is outside the ocean but still active according to the GSSHG coastline/landmask. The striped one is active both according to the ocean landmask and according to GSSHG landmask. How will the interpolated currents affect the two particles? Will both sides of the land be used for the interpolation of the current that in turn affects the particles?

In the yellow box there´s another problem where I´ve sketched a possible yellow particle that according to the GSHHG landmask possibly could take the inner path, sketched as a yellow trajectory. Is this possible (depending on the current forcing) to leave the domain like this and enter it again in another position?

What kind of landmask would be your general recommendation here? Using the ocean or the GSHHG landmask? Or actually create a unique one?

//Sam
pathAndInterpolation.pdf