HYSPLIT nested grid questions

[daved]

I want to do back trajectories with met data generated by WRF runs using a nested grid, but I had some questions. I know that HYSPLIT uses the finest resolution available, but can I do anything to handle edge effects (i.e., use a coarser resolution near the edge of the fine model domain). Do you guys have any other notes or cautions about using HYSPLIT to compute back-trajectories in a nested grid environment. Thanks.

[ariel.stein]

You can use the different WRF nests to calculate the HYSPLIT trajectories. In the CONTROL file, when you describe your meteorological data you just need to include all the nests you want to use. HYSPLIT will sort them out and use the nest highest horizontal resolution first.

[daved]

Thanks for the quick reply. I know I can use the nested data, but my question is, is there any way to tell HYSPLIT to not use the highest resolution at the edge of the high resolution area. So, for example, if I have a 1km grid nested inside a 4km grid, can I tell HYSPLIT to use the 4KM inside the within 8km of the 'edge' of the 1km grid area.

[ariel.stein]

Currently the model jumps to the next horizontal resolution when it is within 2 grid cells of the edge. Changing this condition will require a modification of the source code.

[daved]

Thanks, so much, that's exactly what I needed to know. I talked with a colleague, if 2 grid cells is not enough, we may look into trimming the underlying model fields.

Cheers!