BREEZE HYSPLIT
HYSPLIT - HYbrid Single-Particle Lagrangian Integrated Trajectory
The U.S. Department of Defense required an integrated modeling system consisting of a number of models, of which HYSPLIT is one. To achieve operational performance requirements, DoD requested that BREEZE develop a user-friendly, intuitive interface to this model, complete with data entry, visualization, and reporting utilities.
HYSPLIT Overview
The HYSPLIT (HYbrid Single-Particle Lagrangian Integrated Trajectory) model is the newest version of a complete system for computing simple air parcel trajectories to complex dispersion and deposition simulations.
The dispersion of a pollutant is calculated by assuming either puff 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 mass. In the particle model, a fixed number of initial particles are advected about the model domain by the mean wind field and a turbulent component. The model's default configuration assumes a puff distribution in the horizontal and particle dispersion in the vertical direction. In this way, the greater accuracy of the vertical dispersion parameterization of the particle model is combined with the advantage of having an ever expanding number of particles represent the pollutant distribution.
Some of the model features include:
Trajectories
- Single or multiple (space or time) simultaneous trajectories
- Optional grid of initial starting locations
- Computations forward or backward in time
- Default vertical motion using omega field
- Other motion options: isentropic, isosigma, isobaric, and isopycnic
- Trajectory ensemble option using meteorological variations
- Output of meteorological variables along a trajectory
Air Concentrations
- 3D particle dispersion or splitting puffs (top-hat or Gaussian)
- Instantaneous or continuous emissions, point or area sources
- Multiple resolution concentration output grids
- Wet and dry deposition, radioactive decay, and resuspension
- Emission of multiple simultaneous pollutant species
- Automated source-receptor matrix computation
- Ensemble dispersion with concentration probability output Integrated dust-storm emission algorithm
- Define rate constants to convert one species to another
Ref: http://www.arl.noaa.gov/ready/hysp_info.html