## Search found 176 matches

September 17th, 2019, 8:00 am
Forum: Bugs
Topic: Transport artifact at poles
Replies: 3
Views: 3148

### Re: Transport artifact at poles

The problem is that velocity is converted to grid points per unit time at each met grid point and then the velocity at the computational particle position (in grid points per unit time) is calculated. This causes issues at the poles because (A) the grid spacing at the pole is zero, so velocity in gr...
August 20th, 2019, 7:55 am
Forum: Trajectory Model
Topic: "Flooring effect" on mixing layer depth data generated from GDAS files
Replies: 3
Views: 718

### Re: "Flooring effect" on mixing layer depth data generated from GDAS files

The tutorial contains some help and many examples for scripting runs.
August 19th, 2019, 8:56 am
Forum: Trajectory Model
Topic: "Flooring effect" on mixing layer depth data generated from GDAS files
Replies: 3
Views: 718

### Re: "Flooring effect" on mixing layer depth data generated from GDAS files

By default HYSPLIT does set a minimum mixing depth (150m or 250m depending on the version of HYSPLIT you are using). Please see the documentation on why HYSPLIT uses this default. https://www.ready.noaa.gov/hysplitusersguide/S625.htm Mixed Layer Depth Computation KMIXD is used to control how the bou...
August 9th, 2019, 4:34 pm
Forum: Dispersion Model
Topic: Deposition Velocity
Replies: 4
Views: 1070

### Re: Deposition Velocity

If I understand what you are saying correctly, then yes, you are correct. If you define a constant settling velocity for the particle (by specifying the deposition velocity for a 'particulate' computational particle), then you over-ride the calculation and the settling velocity is the value that you...
August 9th, 2019, 10:12 am
Forum: Dispersion Model
Topic: PARINIT vs. EMITIMES
Replies: 7
Views: 2507

### Re: PARINIT vs. EMITIMES

The PARINIT file basically contains a list of computational particles with their relevant characteristics. (Time, location, mass, etc.) With NINIT=1, HYSPLIT opens the file at the beginning of the simulation and looks for particles with the same time as the run start. If it finds some, then it reads...
August 8th, 2019, 3:20 pm
Forum: Dispersion Model
Topic: even if the option of the pollutant is set to continuous release but is not continuously released.
Replies: 13
Views: 2101

### Re: even if the option of the pollutant is set to continuous release but is not continuously released.

Please review the tutorial to understand how changing the particle number affects results.

Section 7 is particularly relevant.
July 31st, 2019, 6:45 pm
Forum: Dispersion Model
Topic: Deposition Velocity
Replies: 4
Views: 1070

### Re: Deposition Velocity

This section of the tutorial may help you. https://www.ready.noaa.gov/documents/Tutorial/html/chem_linear.html If particle diameter, density, and shape are all 0, then the computational particle is treated as a gas and no gravitational settling is applied, but dry deposition may occur when the compu...
July 29th, 2019, 1:33 pm
Forum: Dispersion Model
Topic: Diameter (µm) Density (g/cc) and Shape
Replies: 6
Views: 1262

### Re: Diameter (µm) Density (g/cc) and Shape

The lat lon coordinate for the HYSPLIT concentration grid is generally the center of the cell (for computational particles on a square concentration grid). Met data output is valid for the point at which it is output. For computational particles which are between met grid points, the met data is int...
July 29th, 2019, 7:43 am
Forum: Dispersion Model
Topic: even if the option of the pollutant is set to continuous release but is not continuously released.
Replies: 13
Views: 2101

### Re: even if the option of the pollutant is set to continuous release but is not continuously released.

Yes - you are exceeding the number of particles / puffs allowed. That is what this warning in the MESSAGE file means. WARNING emspnt: exceeding puff limit WARNING depsus: exceeding puff limit NOTICE main: 168 58515839 10000 2.6298373E+14 WARNING emspnt: exceeding puff limit HYSPLIT will not emit mor...
July 26th, 2019, 8:29 am
Forum: Dispersion Model
Topic: even if the option of the pollutant is set to continuous release but is not continuously released.
Replies: 13
Views: 2101

### Re: even if the option of the pollutant is set to continuous release but is not continuously released.

Thank you for explaining more.