刀利ダムにおける水温と気温の関係 The Relation between the Water Temperature and the Air Temperature at the Touri Dam
A survey of the water temperature and the air temperature at the Touri Dam has produced the following findings. (1) The average water temperature in summer was 13.3℃ in May, 18.4℃ in June, 21.5℃ in July and 23.0℃ in August. (2) The average water temperature in winter was 7.1℃ in December, 4.4℃ in January, 2.7℃ in February and 3.5℃ in March. (3) Let Y be the average water temperature for every 5 days and let X be the average air temperature for every 5 days. It was found that the values of Y were most highly correlated to those of X observed 10 days earlier. Hence, the two sets of temperature data, re-plotted to remove the time lag factor, show the following regression line : Y=0.780X+2.95 with a correlation coefficient of 0.994. (4) The max. Y was 23.8℃ at the Touri dam, which is at EL. 350m. And it was 4.6℃ higher than the one obtained at the Shougawa headwork, located at a lower altitude of EL. 110m. This rather incongruous high temperature can be attributed to the formation of the 'thermo-layer' in the dam reservoir.
富山県立大学紀要 1, 100-106, 1991-03-30