2022 Volume 33 Pages 1-13
The purpose of this study is to formulate an estimation method for airborne chloride in consideration of wind conditions and surrounding topography. The relation between wind conditions from AMeDAS or MSM (Meso Scale Model) and the amount of airborne chloride was studied. As a result, it was confirmed that the amount of airborne chloride is proportional to the square of wind velocity when the wind velocity is 4 m/s or higher. Because the frequency of the square of wind velocity of 4 m/s or higher calculated by a statistical method using Box-Cox transform follows a normal distribution, the sum total value of the square of the wind velocity for one year was estimated by interval estimation. Furthermore, the estimation of the amount of airborne chloride was performed in consideration of the surrounding topography using LightGBM, which is an algorithm for machine learning. The estimation results generally agreed with the measured values. Further, the influences of the surrounding topography on the amount of airborne chloride were visualized by using SHAP values.