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.
Questions regarding the relationship between NUMPAR and MAXPAR
Re: Questions regarding the relationship between NUMPAR and MAXPAR
Could you include your CONTROL and SETUP files, as well as the beginning of the MESSAGE file?
You want to use 2,500 particles over 100 hours of emission, which corresponds to only 25 particles per hour.
How many locations are you releasing particles from, and what is your time step?
HYSPLIT generally does not allow zero particles to be released from an emission location or during a time step for which there is an emission. Therefore, if the requested number of particles is not sufficient to allocate at least one particle to every emission location at every release time, HYSPLIT will increase the total number of particles released beyond NUMPAR but not above maxpar.
For example, if:
(number of time steps per hour) × (number of release locations) > 25
then HYSPLIT would increase the number of particles released.
The CONTROL and SETUP files, along with the beginning of the MESSAGE file, would help determine exactly how the particles are being allocated in your case.
You want to use 2,500 particles over 100 hours of emission, which corresponds to only 25 particles per hour.
How many locations are you releasing particles from, and what is your time step?
HYSPLIT generally does not allow zero particles to be released from an emission location or during a time step for which there is an emission. Therefore, if the requested number of particles is not sufficient to allocate at least one particle to every emission location at every release time, HYSPLIT will increase the total number of particles released beyond NUMPAR but not above maxpar.
For example, if:
(number of time steps per hour) × (number of release locations) > 25
then HYSPLIT would increase the number of particles released.
The CONTROL and SETUP files, along with the beginning of the MESSAGE file, would help determine exactly how the particles are being allocated in your case.