Predicting regions susceptible to high concentrations of airborne volcanic ash in the North Pacific region

Airborne ash probability distribution (AAPD) maps have been generated to show the distribution of airborne volcanic ash in the North Pacific (NOPAC) region by simulating volcanic eruption clouds from 22 of the 100 most historically active volcanoes in the region. The PUFF ash-dispersion model was run daily using archived wind field data between 1994-1995 and 1997-2001 for low and high aircraft flight levels. Subsequent statistics are generated representing the distribution of simulated airborne ash at 6- and 24-h intervals, defining the regions most likely to contain airborne ash and the direction and distance a volcanic ash cloud may propagate from a given volcano. The AAPD maps show the extent of ash from a given volcano can encompass all of Alaska, most of the North Pacific Ocean, portions of northwestern North America, regions as far south as 35°N, regions over the western Arctic Ocean, and portions of eastern Russia. In general, low-altitude atmospheric regions (3-8 km ASL) are more susceptible to airborne volcanic ash when compared to regions above 8 km ASL due to the eruption characteristics of volcanoes in the North Pacific and the region's atmospheric profile. The results indicate that the paths of many NOPAC air traffic routes coincide with airborne ash distribution probability maxima. The upper atmospheric region most likely to contain airborne ash is located off the eastern coast of the Kamchatkan Peninsula, and is generally centered over the heavy air traffic flight corridor of the NOPAC. Although this paper focuses on the NOPAC region, the technique can be directly applied to other regions characterized by active volcanism.