[M-IS11] Mountain Science

[MIS11-01] Differences in air temperature fluctuations depending on altitude and season in the Japan Alps region

*Keisuke Suzuki¹ (1.Research Center for Mountain Environment, Shinshu University)

Keywords:annual mean air temperature, seasonal mean air temperature

The annual mean air temperature at observation sites at low altitudes in Japan has a good correlation with latitude, being higher at points farther south and lower at points farther north. On the other hand, the annual mean air temperature at observation sites at high altitudes is lower than that at observation sites at lower altitudes. Furthermore, it has been reported that although the trend of air temperature increase in recent years at observation sites at low altitudes is remarkable, the trend of air temperature increase at observation sites at high altitudes is not necessarily clear. Therefore, we will examine recent trends in air temperature fluctuations in the Japan Alps region. Over the past 34 years at 14 sites in the Japan Alps region, there are many sites where the increasing trend in annual mean air temperature at low altitude points is statistically significant, but the increasing trend in annual mean air temperature at high altitude sites is unclear. Regarding the mean winter air temperature, the fluctuation trend is not statistically significant at any location, with 9 out of 14 sites showing a downward trend over the past 34 years. Seasonal mean air temperatures in spring and summer have been on the rise for the past 34 years at all locations. Regarding the mean autumn air temperature, there is a statistically significant upward trend only in Matsumoto at a significance level of less than 1%. At Mt. Fuji, Takayama, and Kofu, there is a statistically significant upward trend at a significance level of less than 5%. At points in the Japan Alps region that are relatively low in altitude and have a large surrounding population, there has been a noticeable trend in air temperature increases in recent years. At points with relatively high altitudes and not many surrounding populations, the trend of air temperature fluctuations over the past 34 years is not clear.