Search found 257 matches

by alicec
September 14th, 2020, 8:57 am
Forum: Conversion programs
Topic: ERA5 - projection conversion method
Replies: 1
Views: 160

Re: ERA5 - projection conversion method

Could you please give more information about what you are doing.
Please include how you are downloading the ERA5 data and what conversion programs you are using.
Thank you.
by alicec
August 14th, 2020, 5:11 pm
Forum: Dispersion Model
Topic: Turbulent Structures
Replies: 1
Views: 228

Re: Turbulent Structures

I'm fairly sure what you are seeing is just an artifact. I think what you are seeing is that the release of the mass is actually not continuous. The model can only create new particles at a time step. So the particles are being released at every time step, but you are in a situation where there is n...
by alicec
August 13th, 2020, 11:19 am
Forum: Developers
Topic: Initial HYSPLIT time step
Replies: 1
Views: 667

Re: Initial HYSPLIT time step

When a time step smaller than 1 minute is needed we would recommend use of the inline HYSPLIT.
https://www.arl.noaa.gov/hysplit/inline ... -coupling/
by alicec
August 13th, 2020, 7:46 am
Forum: Users
Topic: Emission file
Replies: 2
Views: 559

Re: Emission file

The EMITIMES file is only for dispersion runs. Using a nonzero value in the heat field causes the model to simulate plume rise due to buoyancy. This may or may not affect downwind dispersion much depending on meteorological conditions and so forth. https://ready.arl.noaa.gov/hysplitusersguide/S417.h...
by alicec
July 15th, 2020, 4:41 pm
Forum: Dispersion Model
Topic: Lateral Diffusion within Plume
Replies: 1
Views: 244

Re: Lateral Diffusion within Plume

Often the turbulent mixing in volcanic plume simulations is quite low as the mixing decreases with height. To increase mixing you can try several things. https://ready.arl.noaa.gov/hysplitusersguide/S625.htm Use kzmix and tvmix to increase the mixing coefficients. Try using kdef=1 to compute horizon...
by alicec
July 15th, 2020, 4:16 pm
Forum: Dispersion Model
Topic: Instantaneous wind fields as input?
Replies: 4
Views: 394

Re: Instantaneous wind fields as input?

3 hourly and 2-5km is a fairly big mismatch in resolutions. The mean vertical velocity tends to be a problem (values are often too large especially in convective regions) when you have low temporal resolution and high spatial resolution. There are two vertical motion methods that were designed to he...
by alicec
July 8th, 2020, 3:57 pm
Forum: Dispersion Model
Topic: Instantaneous wind fields as input?
Replies: 4
Views: 394

Re: Instantaneous wind fields as input?

Yes - it is common practice to use the instantaneous winds instead of averaged. This is adequate in many situations, but not all. HYSPLIT has several different options for estimating the turbulent velocity variance. see KBLS, KBLT, KDEF https://ready.arl.noaa.gov/hysplitusersguide/S410.htm as well a...
by alicec
July 8th, 2020, 3:30 pm
Forum: Users
Topic: What should i do to use advanced tab in DOS
Replies: 3
Views: 292

Re: What should i do to use advanced tab in DOS

The advanced menu items are set in the SETUP.CFG file. file parameters can be found here. https://ready.arl.noaa.gov/hysplitusersguide/S410.htm The particular ones you are looking for are MAXPAR NUMPAR https://ready.arl.noaa.gov/hysplitusersguide/S623.htm There is no executable to set the options in...
by alicec
July 6th, 2020, 2:33 pm
Forum: 7. Air concentration calculations
Topic: Displays Particle Position
Replies: 3
Views: 318

Re: Displays Particle Position

Can you give us some more information?
Please include the plot that is being produced as well as the CONTROL and SETUP.CFG file
which produced the output. If you can include the MESSAGE file that would be helpful as well.

Thank you!
by alicec
July 6th, 2020, 2:30 pm
Forum: Conversion programs
Topic: ERA5 in model levels or pressure levels?
Replies: 1
Views: 311

Re: ERA5 in model levels or pressure levels?

Currently the converter will only handle pressure levels.
If you have the inclination to help modify the converter (era52arl.f) to handle the model levels we can provide some support for doing that.