Volcanic Ash Graphic Information and Dispersion Forecast Chart
Volcanic Ash Graphic Information (Volcanic Ash Nephanalisys)
The graphic information shows the area, height, moving speed and direction of volcanic ash clouds based on the analysis of satellite imagery. Air routes, ATS/MET reporting points and locations of major airports are depicted as well.


Volcanic Ash Dispersion Forecast Chart
Tokyo VAAC generates and provides the volcanic ash dispersion forecast chart describing the outlook for the ash clouds when the location and extent of volcanic ash clouds are specified using satellite images.
  • The chart represents outlooks for the area of volcanic ash clouds for every 6 hours up to 18 hours with 3 levels from surface to 55,000 feet. Outlook is calculated with a Lagrange-type trajectory model developed by Tokyo VAAC using the latest three-dimension forecasted atmospheric field of the global numerical weather prediction system of JMA.
<Sample chart>



Specification of the Dispersion model of Tokyo VAAC

  • Type --> Lagrange
  • Forecast domein --> Global
  • Forecast valid --> 24hr (maximum 30hr)
  • Time step --> 10minutes
  • Particle size and Number --> 0.005mm - 0.1mm, 100,000
  • Physical process --> Fallout
  • Wind field --> JMA/GMS, RSM, MSM