Characteristics of the Japanese Alps region

The Japanese Alps is a collective name for the Hida Mountains, Kiso Mountains, and Akaishi Mountains, spreading approximately 200 km north to south and 100 km east to west. In a wider sense, the Japanese Alps region includes the Ryohaku Mountains in the west and Mt. Fuji, Mt. Yatsugatake, and the Mikuni Mountains in the east, bringing the geographical span of the region to more than 200 km in the east west direction. The altitude of the Japanese Alps summit is around 3,000 m; however, the climate conditions vary widely because it lies in the center of Honshu between the Japan Sea coast and the Pacific coast, with the northern area being known to experience one of the heaviest snowfalls in the world. The vegetation is a mix of circumpolar, northern, and continental elements. It is the habitat of many treasured alpine butterflies and is the southern-most habitat of the Ptarmigan on the planet. Because there are no glaciers in the Japanese Alps, the ecological system constituents such as alpine butterflies or the Ptarmigan are considered to be the remaining survivors from the last glacial period. However, the ecological system is quite sensitive to global-scale environmental changes. Therefore, the mountain ecological system exists under strict and critical environmental conditions (air temperature or hydrological factors). Additionally, global warming has a stronger influence in a smaller space because the temperature decreases more at higher altitudes. Next, we will show that the temperature change is dramatically larger with a change in elevation than with a horizontal change. Figure 1 shows the relationship between the latitude of the meteorological bureau office and the annual mean air temperature. Naturally, the further north the obserbation site is, the bigger the decrease in the annual mean air temperature. We can recognize a good correlation between the latitude and annual mean air temperature, except for the high – altitude Mt. Fuji and the observation sites marked on Fig. 1. According to this relation, for a

Characteristics of the Japanese Alps region

Fig. 1. Relationship between the latitude of the meteorological bureau office and the annual mean air temperature

change of 1 °C in the annual mean air temperature, one must move 118 km north or south. However, if the lapse rate of the air temperature is 0.65 °C/100 m, then a 154 m changes in elevation will bring about a change of 1 °C in air temperature. Thus, the air temperature change due to altitude variation is almost 800 times more drastic than that due to horizontal variation. The distribution of vegetation is perspectively determined by air temperature, so it is difficult to realize the horizontal vegetation change; however, in mountain areas where the air temperature changes rapidly with elevation, the vegetation is very sensitive to global warming. Furthermore, because of the warming, vegetation that has adapted to the high altitude and colder environment could lose its habitat. Changes in vegetation will change the distribution of insects and consequently affect larger animals. Thus, global-scale environmental change will impact the mountain area directly.

In Fig. 1, data that are out of regression line have been named and their locations (circles) and elevations are shown on the map in Fig. 2. The altitude of the observation site on Mt. Fuji is 3,775 m, and it is the highest observation site of the Japan Meteorological Agency. The second highest one, which records temperature, humidity, wind, precipitation, and snow depth, is Nikko, whose altitude is 1,292m. Ten sites, including Nagano with an altitude of 418 m, are located at high altitudes, and the effect of high altitude is coupled with that of temperature change; hence we can see that they are out of the regression line in Fig. 1. All of the sites except for Asosan and Nikko are located in the Japanese Alps region.

Characteristics of the Japanese Alps region

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