Development of PUFF\u2013Gaussian dispersion model for the prediction of atmospheric distribution of particle concentration

Jooyong Lee,HyunA Son,Waon-ho Yi,Sungsu Lee

doi:10.1038/s41598-021-86039-y

Abstract

Mt. Baekdu’s eruption precursors are continuously observed and have become a global social issue. Volcanic activities in neighboring Japan are also active. There are no direct risks of proximity-related disasters in South Korea from the volcanic eruptions at Japan or Mt. Baekdu; however, severe impacts are expected from the spread of volcanic ash. Numerical analysis models are generally used to predict and analyze the diffusion of volcanic ash, and each numerical analysis model has its own limitations caused by the computational algorithm it employs. In this study, we analyzed the PUFF–UAF model, an ash dispersion model based on the Lagrangian approach, and observed that the number of particles used in tracking substantially affected the results. Even with the presence of millions of particles, the concentration of ash predicted by the PUFF–UAF model does not accurately represent the dispersion. To overcome this deficit and utilize the computational efficiency of the Lagrangian model, we developed a PUFF–Gaussian model to consider the dispersive nature of ash by applying the Gaussian dispersion theory to the results of the PUFF–UAF model. The results of the proposed method were compared with the field measurements from actual volcanic eruptions, and the comparison showed that the proposed method can produce reasonably accurate predictions for ash dispersion.

Highlights

The Lagrangian model sets the number of particles to an initial value to calculate the pollutant particle diffusion, and it is affected by the diffusion range and the concentration of the result
This study addresses the development of the PUFF–Gaussian model by applying the Gaussian dispersion theory that considers mass diffusion to compensate for the predicted concentration discontinuity
The PUFF–UAF model uses wind data to track the diffusion motion of volcanic ash modeled into individual particles to perform volcanic ash diffusion predictions, and the volcanic ash particle position is calculated by Eq (1) at each time step[10]

Summary

Introduction

The Lagrangian model sets the number of particles to an initial value to calculate the pollutant particle diffusion, and it is affected by the diffusion range and the concentration of the result. In order to demonstrate the effect of the number of particles on the concentration prediction, volcanic ash dispersion analysis was performed using the PUFF–UAF model for the Shinmoedake V olcano[12] in Japan, which erupted on January 26, 2011.

Results

Conclusion