Define the particle size, density, shape factor, and mass distibution of the ash for the HYSPLIT simulation. The four-character identifier is arbitrary and is written to the binary output file.
On the web, up to 4 particle size bins may be specified. For those not needed, enter 0.0 for the mass fraction.
The sum of the mass fraction(s) must equal 1.0.
In HYSPLIT, particles move and are dispersed by the wind; inertial motion is not simulated. Hence for particles larger than a couple hundred micrometers, the results become less accurate.
Gravitational settling velocity is calculated using the particle diameter, density, and shape factor.
The default GSD is from Hobbs et al., 1991.
Reference Hobbs, P.V. et al., 1991: Airborne measurements of particle and gas emissions from the 1990 volcanic eruptions of Mount Redoubt, J. Geophys. Res., 96, 18735-18752.
Also see the list of Frequently Asked Questions
and the
HYSPLIT model documentation.