HYSPLIT Forum: hysplitbbs.arl.noaa.gov

The website limitation https://ready.arl.noaa.gov/hypub/limitations.html is not working for me and I want to know what the limitations of Hysplit and compare with Flexpart

Hello, I am a PhD Student, I want to backtrack airmasses coming to an atmospheric station. What time interval should I choose for CO2 and CH4 and Water vapor and Carbon Monoxide? Should I go back by 6 hours for 10 days or what is convenient for this study? I have searched a lot for this question and...