maxpar with negative number of numpar

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josh4ever
Posts: 2
Joined: September 20th, 2020, 2:45 pm
Registered HYSPLIT User: Yes

maxpar with negative number of numpar

Post by josh4ever »

Hello,

Maxpar does not looks override with negative number of numpar.

I set two different maxpar values with same negative numpar value, but both outputs are different. The output with smaller maxpar value has a smaller particle deposition. Please help me to override maxpar.

Thank you.
alicec
Posts: 380
Joined: February 8th, 2016, 12:56 pm
Registered HYSPLIT User: Yes

Re: maxpar with negative number of numpar

Post by alicec »

Negative numpar means that the number of particles will be released per hour rather than per emission cycle.

So for instance if you have a relatively simple setup with 12 hour emission cycle and numpar = 12000 that means, 12000 particles
will be released over 12 hours, 1000 particles per hour.

However if you set numpar=-12000 that means 12000 particles are released every hour
and total number of particles over 12 hours would be 12000 * 12hours = 144000 particles.

So if you have maxpar set to something like 50,000 then emissions would stop after about 4 hours for the numpar=-12000 case, because the maximum number of particles would be reached. This would probably cause your deposition to be smaller.

You can check your MESSAGE file to see if you are getting a warning about number of particles reached. WARNING EMSPNT: exceeding puff limit
https://www.ready.noaa.gov/hysplitusersguide/S443.htm

You may just need to increase maxpar.
https://www.ready.noaa.gov/hysplitusersguide/S623.htm
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