## HYSPLIT - Hybrid Single Particle La grangian Integrated Trajectory Model HYSPLIT Description The HYSPLIT (HYbrid Single-Particle Lagrangian Integrated Trajectory) model is a complete system for computing simple air parcel trajectories to complex dispersion and depos ition simulations. The intial development was a result of a joint effort between NOAA and Australia's Bureau of Meteorology . Recent upgrades include enhancements provided by a number of di fferent contributors. Some new features include improved advection algorithms, updated stability and dispersion equations, continued improvements to the graphical user interface, and the option to include modules for chemical transformations. Without the additional dispersion modules, Hysplit computes the advection of a single pollutant parti cle, or simply its trajectory. The dispersion of a pollutant is calcul ated by assuming either puf f or particle dispersion. In the puff model, puffs expand until they exceed the size of the meteorological grid cell (either horizontally or vertically) and then split into several new puffs, each with it's share of the pollutant ma ss. In the particle model, a fi xed number of particles are advected about the model domain by the mean wind fiel d and spread by a turbulent component. The model's default configuration assumes a 3-dimensional particle distribution (hor izontal and vertical). The model can be run interactively on the Web through the READY system on our site or the code executable and met eorological data can be downloaded to a Windows or Mac PC. The web version has been configured with some limitations to avoid computational saturati on of our web server. The regi stered PC version is complete with no computational restrictions, except that user's must obtain their own meteorological data files. The unregistered version is ide ntical to the registered ve rsion except that plume concentrations cannot be calculated with with forecast meteorology data files. The traj ectory-only model has no restrictions an d forecast or archive trajectories may be computed with either version.



### Model Features Trajectories Single or multiple (space or time) simultaneous trajectories Optional grid of initial starting locations Computations forward or backward in time Default vertical mo tion using omega field Other motion options: isentropic, isosigma, isobaric, isopycnic Trajectory ensemble option us ing meteorological variations Output of meteorological variables along a trajectory Integrated trajectory clustering option 

### Air Concentrations 3D particle dispersion or splitt ing puffs (top-hat or Gaussian) Instantaneous or continuous emi ssions, point or area sources Multiple resolution concentration output grids Fixed concentration grid or dynamic sampling Wet and dry deposition, radioactive decay, and resuspension Emission of multiple simu ltaneous pollutant species Automated source-receptor matrix computation Ensemble dispersion based on variations in meteorology, turbulence, or physics Concentration probability out put for multiple simulations Integrated dust-sto rm emission algrorithm Define rate constants to convert one species to another Mass can be transferred to a Eulerian module for global-scale simulations 

# Pa g e 1 of 2 Air Resources Laboratory - HYSPLIT - H y brid Sin g le Particle La g ran g ian Inte g rated Tra j

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3/31/2014 http ://www.arl.noaa. g ov/HYSPLIT

_info. p h pModified: April 11, 2012 Dept. of Commerce | NOAA | NOAA Research | Website owner: ARL Privacy | Disclaimer | Information Quality Site Map | Accessibility | webmaster 

### Meteorology Model can run with multip le nested input data grids Links to ARL and NWS meteorological data server Access to forecasts and archives including NCAR/NCEP reanalysis Additional software to convert MM5, RAMS, COAMPS, WRF, and other data Utility programs to display and manipulate meteorological data 

### Common Features Tcl/Tk GUI with integrated html compatible help Viewer to display TOMS aerosol index with model particle positions Model restart from particle positi on files for plume initialization Model graphics displayed as Postscript files Converters to many other format s: GIF, GrADS, ArcView, Vis5D


### Further Information HYSPLIT Summary Handout (PDF, 250 KB) 

# Pa g e 2 of 2 Air Resources Laboratory - HYSPLIT - H y brid Sin g le Particle La g ran g ian Inte g rated Tra j

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3/31/2014 http ://www.arl.noaa. g ov/HYSPLIT

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