HYSPLIT Forum: hysplitbbs.arl.noaa.gov

I am using both NAM and GDAS dataset to simulate the backward trajectories. I wonder is there a higher resolution roughness length and terrain file that would be more appropriate for use with NAM data? Do the RGHS and SHGT fields in the NAM data downloaded through HYSPLIT override the 1*1 degree roughen.asc and terrain.asc files in/bdyfiles? Thank you!

If the meteorological data set contains surface height or roughness length,the model will overwrite the data read from these files. Most of our forecast files contain both these fields including the NAM, however the GFS does not. We do not have a better resolution file available so you would need to find the information and modify these files for use by HYSPLIT.