Questions regarding the relationship between NUMPAR and MAXPAR
Posted: July 17th, 2026, 12:47 pm
Dear HYSPLIT master and user of HYSPLIT.
I have checked the user guide and some Q&A posts on the forum, but I still have a few questions and some points I don’t quite understand.
For example, when using the HYSPLIT dispersion model to simulate a continuous release, I set some parameters as follows:
Total run time (hrs) = 100
Hours of emission = 100
Repeat emission cycle = 0.0 (which I think should be the parameter that controls QCYCLE)
Particles released per cycle (NUMPAR)=2500
Maximum number of particles (MAXPAR)=10000
Maximum particle duration (KHMAX)=9999
In that case, from my understanding, the 100-hour continuous release should have released only 2500 particles in total, and the emissions are not cycled.
If so, why does the program still show the warning "WARNING particle array limit reached; emissions turned off", which indicates that the MAXPAR (10000) limit has been reached?
I think I have misunderstood NUMPAR, MAXPAR, or the release mechanism. I sincerely hope someone can help clarify this.
Thank you advanced.
I have checked the user guide and some Q&A posts on the forum, but I still have a few questions and some points I don’t quite understand.
For example, when using the HYSPLIT dispersion model to simulate a continuous release, I set some parameters as follows:
Total run time (hrs) = 100
Hours of emission = 100
Repeat emission cycle = 0.0 (which I think should be the parameter that controls QCYCLE)
Particles released per cycle (NUMPAR)=2500
Maximum number of particles (MAXPAR)=10000
Maximum particle duration (KHMAX)=9999
In that case, from my understanding, the 100-hour continuous release should have released only 2500 particles in total, and the emissions are not cycled.
If so, why does the program still show the warning "WARNING particle array limit reached; emissions turned off", which indicates that the MAXPAR (10000) limit has been reached?
I think I have misunderstood NUMPAR, MAXPAR, or the release mechanism. I sincerely hope someone can help clarify this.
Thank you advanced.