Search found 140 matches

by alicec
June 21st, 2019, 9:15 am
Forum: Dispersion Model
Topic: Time Step and Concentration Calculation
Replies: 34
Views: 476

Re: Time Step and Concentration Calculation

There will be differences because the random numbers generated on the two systems will not be the same. To see this on the same system, you can set the SEED parameter in the SETUP.CFG (at least if you have a more recent version). https://ready.arl.noaa.gov/hysplitusersguide/S410.htm Try running with...
by alicec
June 19th, 2019, 9:19 am
Forum: Dispersion Model
Topic: the numbers of emitors
Replies: 5
Views: 83

Re: the numbers of emitors

The main output of a dispersion run is a binary file which we often refer to as a cdump file.
This file can be converted to ascii output as described here:
https://ready.arl.noaa.gov/hysplitusersguide/S341.htm
by alicec
June 19th, 2019, 9:13 am
Forum: Dispersion Model
Topic: Time Step and Concentration Calculation
Replies: 34
Views: 476

Re: Time Step and Concentration Calculation

Try the following: 1. Repeat your runs with the deposition turned off. 2. Look and see how many particles HYSPLIT emitted. I think what you are running into is that HYSPLIT takes NUMPAR, number of particles to release, as a guide. When you go to the 24 hour emissions cycle, HYSPLIT wants to release ...
by alicec
June 18th, 2019, 5:30 pm
Forum: Dispersion Model
Topic: the numbers of emitors
Replies: 5
Views: 83

Re: the numbers of emitors

See the documentation below for an explanation of KRAND. Do you mean you do not have any cdump file output when setting KRAND? HYSPLIT will automatically use KRAND=1 if numpar > 5000 so you only have to set it if you want KRAND=2. https://www.ready.noaa.gov/hysplitusersguide/S640.htm KRAND (2) - if ...
by alicec
June 18th, 2019, 8:50 am
Forum: Dispersion Model
Topic: the numbers of emitors
Replies: 5
Views: 83

Re: the numbers of emitors

HYSPLIT run time depends on several factors including - number of computational particles which are being simulated - model time step (which depends on grid size. Finer grids need smaller time steps). - system configuration One thing you can do is to break up your run into smaller runs. Instead of d...
by alicec
June 17th, 2019, 11:03 am
Forum: Dispersion Model
Topic: Time Step and Concentration Calculation
Replies: 34
Views: 476

Re: Time Step and Concentration Calculation

Please check that your concentration grid is large enough so that the particles are not being deposited outside of your grid.
That would cause the number of particles that you are calculating from the output file to be lower than you expect.
by alicec
June 17th, 2019, 9:52 am
Forum: Dispersion Model
Topic: Time Step and Concentration Calculation
Replies: 34
Views: 476

Re: Time Step and Concentration Calculation

1. Small particles reach a terminal fall velocity very quickly. So the gravitational settling velocity is a constant. There is extensive literature on how to estimate the terminal fall velocity of a particle given shape, size, and density. This is probably not relevant for insects though. 2. Yes - d...
by alicec
June 17th, 2019, 8:05 am
Forum: Dispersion Model
Topic: Time Step and Concentration Calculation
Replies: 34
Views: 476

Re: Time Step and Concentration Calculation

Please see this help page and some of the references quoted within. https://ready.arl.noaa.gov/hysplitusersguide/S314.htm The deposition velocity is simply defined such that the the flux of material to the surface is the deposition velocity multiplied by the concentration above the surface. e.g. (kg...
by alicec
June 14th, 2019, 2:41 pm
Forum: 2019 HYSPLIT Workshop Questions
Topic: The resistance method for particle deposition
Replies: 1
Views: 49

Re: The resistance method for particle deposition

Great - we will talk about this at the sessions on Monday and Tuesday.
Thanks for attending the workshop.
by alicec
June 14th, 2019, 11:39 am
Forum: Dispersion Model
Topic: Time Step and Concentration Calculation
Replies: 34
Views: 476

Re: Time Step and Concentration Calculation

Did you convert degrees to radians when using the cosine function in excel?