Incorporating features from the Stochastic Time-Inverted Lagrangian Transport (STILT) model into the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model: a unified dispersion model for time-forward and time-reversed applications

Abstract The Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model is a state-of-the-science atmospheric dispersion that developed and maintained at the National Oceanic Atmospheric Administration’s (NOAA) Air Resources Laboratory (ARL). In early 2000s, HYSPLIT served as starting point for development of Stochastic Time-Inverted Transport (STILT) emphasizes backward-in-time simulations to determine source regions receptors. STILT continued its separate gained wide user base. Since was built on now outdated version lacks long-term institutional support maintain model, incorporating features into allows these stay up date. This paper describes incorporated HYSPLIT, which include: new vertical interpolation algorithm WRF derived meteorological input files, detailed estimating boundary layer height, turbulence parameterization, timescale varies in time space, complex algorithm, two convection schemes. An evaluation performed using tracer release data from Cross Appalachian Tracer Experiment Across North America Experiment. Results show module STILT, takes double amount run, less dispersive better agreement with observations than existing option. other modeling were not consistently statistically different options. Forward-time also compared against backward-time equivalents found be comparable one another.