HYSPLIT Forum: hysplitbbs.arl.noaa.gov

Hi everyone,
I have a few questions about deposition and dose calculations that are related to each other as followed;
1- Is it possible to examine wet deposition by using user-entered data? I tried it but not allowed due to the precipitation rate that is given as an error message. However, when ı compared the global data and user-entered data, the main differences between them specific humidity. I guess it is not allowed user-entered data does not include specific humidity. Because wet deposition occurs when particle or gas faces with %80-%60 specific humidity layer.
2- Is it an appropriate calculation computing more radioactive pollutants by adding them separately (each of them have own properties)to pollutant menu with activity, releasing duration, and deposition properties instead of using these values https://ready.arl.noaa.gov/documents/Tu ... tivity.txt ? For example,
Pollutant 1 C137
Pollutant 2 I131
Pollutant 3 Xe135 so on... and is there any limitation because there is 7 pollutant menu in GUI.
3- How can I use the detonation section to customize the simulation? Is there any example as a tutorial?
I m looking forward to hear your answers.

Best regards,

1. Currently the utility, stn2arl, which creates the metfiles from the user entered data does not allow for the inclusion of precip fields.

2-3: You may find material in the advanced tutorial helpful.
https://www.ready.noaa.gov/HYSPLIT_Tutorials.php
https://www.ready.noaa.gov/documents/Tu ... index.html

1- Is it possible to examine wet deposition by using user-entered data? I tried it but not allowed due to the precipitation rate that is given as an error message. However, when ı compared the global data and user-entered data, the main differences between them specific humidity. I guess it is not allowed user-entered data does not include specific humidity. Because wet deposition occurs when particle or gas faces with %80-%60 specific humidity layer.

I assume that you are referencing the section of the GUI "Meteorology / Convert to ARL / User Entered" where you can create your own meteorological data file. If you have access to the source code then you could modify the program "stn2arl.f" to include other meteorological variables! Also there are other related programs within the source code distribution, that are not part of the GUI, such as snd2arl.f and sfc2arl.f, that could also be customized.

Another approach, if you examine the help file discussing other namelist parameters not set by the GUI, is to define your own precipitation file by setting KWET=2. The code will try to open a file called raindata.txt which defines the directory, base, and suffix name of an external precipitation file that is in the ARL standard format. The text file also defines the 4-character name of the precipitation variable as well as the conversion factor from file units to model units (meters/min). The file name is automatically constructed from the prefix and suffix names using current calculation date following the convention: {prefix}{YYYYMMDD}{suffix}. If the raindata.txt file is not found in the startup directory, the model will create a template for manual editing and then stop.

To compensate for the fact that your user-entered precipitation data may not match the default cloud definitions, there are two additional non-GUI namelist variables: RHB (default=80) which defines the initial relative humidity required to define the base of a cloud and RHT (default = 60) which defines the cloud until the relative humidity drops below this value. Note that the RH cloud definitions are also very much a function of the meteorological grid cell size.

Note that in general, the use of precipitation data that is inconsistent with the meteorological fields is discouraged because if you have precipitation but no clouds then it is also very likely the transport winds are incorrect. It is much better to create a physically consistent meteorological data set using assimilation methods through a meteorological model such as WRF.


2- Is it an appropriate calculation computing more radioactive pollutants by adding them separately (each of them have own properties)to pollutant menu with activity, releasing duration, and deposition properties instead of using these values https://ready.arl.noaa.gov/documents/Tu ... tivity.txt ? For example,
Pollutant 1 C137
Pollutant 2 I131
Pollutant 3 Xe135 so on... and is there any limitation because there is 7 pollutant menu in GUI.

The number of pollutants is limited to seven only in the GUI. Once you create the basic CONTROL and SETUP.CFG files through the GUI, you could manually edit them to add more pollutants before running the model, either on the command line or through the GUI. It may not have been clear in the simple example of the Tutorial but you only need to define pollutants for each class of radionuclide that has its own deposition characteristics: for instance perhaps with different particle sizes and/or wet deposition characteristics, and a noble gas for no deposition. Each class of pollutant can then be associated with any number of radionuclides that have the same transport and deposition characteristics. Differences in half-life and dose are applied in the post-processing step of "con2rem".


3- How can I use the detonation section to customize the simulation? Is there any example as a tutorial?

The extended tutorial https://www.ready.noaa.gov/documents/Tu ... index.html provides a more complete discussion about how to configure HYSPLIT for a nuclear detonation. Note that knowledge of scripting is required for all extended topics. The activity.txt file produced by "con2rem" is only a subset of the 200 or so radionuclides produced by fission. To extend this file to other radionucides, users need to develop their own additions using public data sources such as from T.R. England and B.F. Rider, Los Alamos National Laboratory, LA-UR-94-3106; ENDF-349 (1993)

Thanks a lot for all the detailed answers. I really appreciate it
Best regards.