Possibility of predicting basin fog by using the maximum possible cooling amount and surveillance camera images

概要

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We investigated the possibility of predicting fog occurring in a basin by using the maximum possible cooling amount (ΔTmax) and surveillance camera images. The Miyoshi and Takahashi Basins in West Japan were chosen as our study fields. In the Miyoshi and Takahashi basins, ΔTmax exceeded 10°C on about 80% and 70% of all the fog days, respectively. On non-fog days, ΔTmax had a large peak at 4-6°C in both basins. This difference in ΔTmax between fog and non-fog conditions provided the possibility of predicting fog using ΔTmax. For the Miyoshi data, discriminant analysis was conducted with the qualitative variable "fog or non-fog events" and three quantitative variables (ΔTmax, dew-point depression, and wind speed) important for fog generation. A linear discriminant function for "fog or non-fog days" was derived from the result and then evaluated for fog incidences in practice. 67 of the total 82 days fog was observed were predicted as fog days. In other words, the success rate was 81.7%. For non-fog days as well, the success rate was high at 81.8%. The total success rate for fog and non-fog days was 81.8%. Normalized coefficients of the discriminant function revealed that ΔTmax had the most impact on fog incidence, followed by dew-point depression being about half as important. This result suggests that it is possible to predict a basin fog by using only two variables: ΔTmax and dew-point depression.
日本農業気象学会の論文