5:15 PM - 6:45 PM
[SVC31-P08] Development status of Quantitative Volcanic Ash concentration information
Keywords:Aviation weather, Eruption column model, Atmospheric transport model, Quantitative information
Introduction
Volcanic ash can seriously affect air services by causing engine failure and take-off/landing delays due to ash accumulation at airports. To mitigate such effects, the International Civil Aviation Organization (ICAO), in conjunction with the World Meteorological Organization (WMO), recommended the establishment of Volcanic Ash Advisory Centers (VAACs) and designated nine such centers around the world. These facilities are tasked with issuing Volcanic Ash Advisories (VAAs) regarding the extent and predicted movement of volcanic ash. In its role as the VAAC Tokyo, the Japan Meteorological Agency (JMA) has been providing VAAs to organizations such as airlines and aviation authorities.
While VAAs provide only observed and forecast extent of volcanic ash clouds, ICAO is, in response to requests from users, planning to introduce new “Quantitative Volcanic Ash concentration information (QVA, figure)” that predicts volcanic ash concentrations and their probabilities. A major improvement from the current model used for VAA is the development and introduction of a one-dimensional volcanic plume model, “NIKS-1D” (Ishii et al. 2022), which enables quantitative calculations of volcanic ash particles emitted from volcanic plumes into the atmosphere. This presentation will discuss the status of QVA development at VAAC Tokyo.
Details of NIKS-1D
In the current model for comparison, the particles in the plume are distributed based on the approximate function of Suzuki (1983). NIKS-1D is a physical model that calculates the amount of particles emitted from a plume based on the dynamics of the plume (note: “NIKS” stands for the initials of its four developers). The motion of a rising plume column just above a crater is described by an eruption column model (Woods 1988, Bursik 2001), while the motion of a plume flowing at the neutral buoyancy level (NBL) is described by a downwind gravity current model (Bursik et al. 1992). By coupling a particle sedimentation model (Martin and Nokes “1988; Koyaguchi et al. 2009) to each process, the amount of particles that leave the moving plume and those that remain in the plume can be determined. By inputting these amounts into “JMA-ATM” (Shimbori and Ishii 2021), a tephra-dispersal model developed by JMA, and calculating the motion of volcanic ash particles in the atmosphere, quantitative volcanic ash concentration forecasts can be obtained.
Volcanic ash can seriously affect air services by causing engine failure and take-off/landing delays due to ash accumulation at airports. To mitigate such effects, the International Civil Aviation Organization (ICAO), in conjunction with the World Meteorological Organization (WMO), recommended the establishment of Volcanic Ash Advisory Centers (VAACs) and designated nine such centers around the world. These facilities are tasked with issuing Volcanic Ash Advisories (VAAs) regarding the extent and predicted movement of volcanic ash. In its role as the VAAC Tokyo, the Japan Meteorological Agency (JMA) has been providing VAAs to organizations such as airlines and aviation authorities.
While VAAs provide only observed and forecast extent of volcanic ash clouds, ICAO is, in response to requests from users, planning to introduce new “Quantitative Volcanic Ash concentration information (QVA, figure)” that predicts volcanic ash concentrations and their probabilities. A major improvement from the current model used for VAA is the development and introduction of a one-dimensional volcanic plume model, “NIKS-1D” (Ishii et al. 2022), which enables quantitative calculations of volcanic ash particles emitted from volcanic plumes into the atmosphere. This presentation will discuss the status of QVA development at VAAC Tokyo.
Details of NIKS-1D
In the current model for comparison, the particles in the plume are distributed based on the approximate function of Suzuki (1983). NIKS-1D is a physical model that calculates the amount of particles emitted from a plume based on the dynamics of the plume (note: “NIKS” stands for the initials of its four developers). The motion of a rising plume column just above a crater is described by an eruption column model (Woods 1988, Bursik 2001), while the motion of a plume flowing at the neutral buoyancy level (NBL) is described by a downwind gravity current model (Bursik et al. 1992). By coupling a particle sedimentation model (Martin and Nokes “1988; Koyaguchi et al. 2009) to each process, the amount of particles that leave the moving plume and those that remain in the plume can be determined. By inputting these amounts into “JMA-ATM” (Shimbori and Ishii 2021), a tephra-dispersal model developed by JMA, and calculating the motion of volcanic ash particles in the atmosphere, quantitative volcanic ash concentration forecasts can be obtained.