HYSPLIT Forum: hysplitbbs.arl.noaa.gov

Hello,

I am looking at how the output grid resolution affects HYSPLIT performance using measured data. I am quantifying the performance using statistical metrics. It seems that there is no general rule for what output grid resolution should be used. Using a higher resolution (even with more particles) doesn't seem to improve the predictions of the model compared to a coarse resolution. Is this something that is common across all release scenarios or possibly just the scenario that I am looking at.

Any comments would be appreciated.


Thanks

It is not generally true that increased output grid resolution will improve model results. Sometimes it will actually degrade model results.
Generally speaking, higher concentration grid resolution may be beneficial for predicting concentrations at shorter transport distances and times or near the edge of the plume (when the concentration field is more variable), and when you have higher resolution NWP data.
The model is outputting the average concentration over each concentration grid cell. So if you are finding that increasing the resolution isn't
changing your results much, that is probably because the concentration is fairly uniform over that grid cell so an average over a smaller piece is the
same as the average over the larger piece.