Introduction to PySPLIT: A Python Toolkit for NOAA ARL's HYSPLIT Model

The US National Oceanic and Atmospheric Administration Air Research Laboratory's HYSPLIT (HYbrid Single Particle Lagrangian Integrated Trajectory) model uses a hybrid Lagrangian and Eulerian calculation method to compute particle dispersion and deposition simulations as well as air parcel paths (trajectories), forward or backward in time. This model is used worldwide in a variety of scientific contexts. The author presents the first Python package designed from the ground up to facilitate and expedite HYSPLIT trajectory analysis workflows by providing an intuitive and efficient API for generating, inspecting, and plotting trajectory paths and data. PySPLIT enables fully reproducible workflows, with orders of magnitude superior efficiency compared to what was previously possible with HYSPLIT alone, and leverages the capabilities of the scientific Python ecosystem and matplotlib to generate reproducible, publication- quality figures.