Get/Run the HYSPLIT Model - Download the PC or Mac version or run the model on the web.
Registration may be required to access some portions of this page. Additional documentation on the HYSPLIT model and
its meteorological data can also be found
HYSPLIT Basic Tutorial - Want to learn more about HYSPLIT and how
to run the PC/Mac version? Then this online tutorial is the place to start as it will provide you with a good starting
point for running the model appropriately.
HYSPLIT Forum - Have a question about HYSPLIT? Register for the
HYSPLIT Forum and search for an answer to your question or ask the user community for ideas and answers to your specific
HYSPLIT Workshops - NOAA Air Resources Laboratory
presents a PC/Mac HYSPLIT Workshop in the spring or early summer each year and follows the material found in the
HYSPLIT Automated Forecasts - HYSPLIT has been configured to automatically produce
atmospheric dispersion forecasts for several locations four times daily. These locations may change based on the needs
of NOAA and its partners. The model assumes a unit of mass emission over 60 hours and produces graphics for two
concentration grids: a fine grid (~ 1km horizontal resolution) and a coarse grid (~10 km horizontal resolution). Output
on the fine grid extends from hour 1 to hour 12 each hour, while the coarse extends from hour 2 to hour 60 every 2 hours.
Volcanic Ash - Volcanic ash from an erupting volcano can seriously impact the aviation
community. This section presents links to current and hypothetical eruptions within the Washington and Anchorage Volcanic
Ash Advisor Center (VAAC) areas of responsibility. Users can also run the HYSPLIT model for many volcanoes around the
Fukushima NPP Transfer Coefficient Matrix (TCM) - Previously computed HYSPLIT simulations
of the Fukushima Daiichi nuclear power plant accident are used to calculate Cesium-137 and Iodine-131 air concentrations and
depositions from user selected source term estimates. The TCM allows provides an easy method to view the impacts of
source term estimates without having to rerun the model for each case.
Short-Range Ensemble Forecast (SREF) Dispersion Forecasts - The NOAA National Centers for
Environmental Prediction (NCEP)
run a series of model forecasts called the Short-Range Ensemble Forecasting (SREF) system to provide an estimate of the
variability of a single forecast. ARL is experimenting with using the SREF to provide an estimate of the variability one
might expect in the dispersion forecast due to variations in the meteorology used by the model. The source location may
Gaussian Plume Model - A simple model that was once considered the standard dispersion
model for routine calculations is called the Gaussian plume model because it assumes the air pollutant dispersion has a
Gaussian distribution (normal probability distribution). It assumes a constant wind direction and speed and uniform terrain,
which limits its applicability to many atmospheric dispersion problems especially cases where the meteorology is changing
and for calculations distant from the source location. It is still used by some regulatory agencies due to its simplicity.
A simple version of the Gaussian plume model is provided here only to demonstrate its functionality and should not be used
for most transport and dispersion simulations. HYSPLIT is a better choice if looking to use a model to calculate transport
Balloon Flight Forecasting Tools - A tool for manned balloon flight planning has been
developed that allows the user to visualize the potential flow combinations from up to three different starting heights,
multiple times along the flight track. This tool uses the HYSPLIT model trajectories to determine where a balloon might
travel if the height of the balloon is changed along the flight path and can help "steer" a balloon to a particular location
or avoid a location such as calm winds.
Locusts - Countries in Eastern Africa and the Middle East are affected by outbreaks of desert locust swarms, creating significant threats to food security in these regions. Advance knowledge of where a given swarm might go, and/or where it might have come from, can aid efforts to mitigate the devastating impacts caused by these voracious pests. Locusts are believed to be relatively passive fliers, with movements primarily influenced by the wind. They also fly together in a swarm, making them ideal candidates for simulation using HYSPLIT’s air trajectory modeling capabilities. ARL’s innovative web app allows users to specify takeoff and landing times (e.g., relative to sunset and sunrise) and flying height(s) to create forward or backward simulations from identified swarm locations. A batch input functionality is also available, enabling the user to upload data for up to 20 swarms simultaneously and generate corresponding results with the singular push of a button.