[Forecast of the beginning day of Japanese cedar pollen release using variation pattern in air temperature]

It is important to forecast the beginning day of Japanese cedar pollen release for taking the preventive medical measure. We analyzed the relation between the beginning day of pollen release and the changing pattern of daily air temperature. A simple and practical method for forecasting the beginning day of pollen release is suggested. Polynomial of degree three was applied to represent the general variation pattern of air temperature. Multiple correlation coefficients between parameters of the polynomial and the beginning days of pollen release were 0.88 for the difference by year, and 0.81 for the difference by place. It was shown that the minimum value and the date of the fitted polynomial curve were related closely to the difference in the beginning day of pollen release by year. The minimum value and the date of the original series of air temperature showed high correlation with the difference in the beginning day of pollen release by place. We propose to use the minimum value and the date of original series and fitted curve of air temperature for forecasting the beginning day of cedar pollen release.