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The reduction of alpine moors caused by climatic change. - the relationship of moor, snow and jet stream -.

YASUDA, Masatsugu*,1, 1 Forest Ecology Labolatory, Faculty of Holticulture, Chiba University, 648, Matsudo, Matsudo-shi, Chiba, Japan

ABSTRACT- I studied on the reduction of alpine moors caused by the climate change in Japan, comparing it with the decline of precipitation of snow. Recently, it was reported that the moors at Echigo mountain range, located on central Japan, has getting arid and decrease. And I investigated the vegetation of moors at Echigo mountain range and found that most of them had turned into forest type vegetation. This change might be caused by the dryness there. To try to find the cause of it, I makes a comparative study of the change in the snow amount past years. Because that moors are the water is supplied from the snow. Then we analyzed the long-term fluctuation of precipitation at that region. And the research shows that the snow amount has been declining since the latter half of 1970′s. Next, I researched the atmospheric pressure patterns of the Far East. Because the precipitation of Japan in winter greatly depends on the arrangement of the atmospheric pressure. And, the passage of the low-pressure in the sky over Japan moved south as a result. The moving route of the low-pressure in the sky over Japan changes by the jet stream channel. Then, I researched the upper air stream by NCEP-NCAR 500Hp data. And I found a upper air stream pattern that synchronizes with precipitation. I finally recognized that caused to change in the flow of upper atmosphere influenced on atmospheric depression. Then, at the last, I verified how climatic change exerts an influence upon the vegetation, using the growth rate of the tree rings. I could see the rate is on the rise recently. I got a very similar result of tendency of change when we compared the growth rate of the tree rings to the yearly amount of snowfall. I can conclude to say that tendency toward drying was caused by the decrease of snowfall. As a result, we confirmed that the reduction of moors comes from the decrease of snowfall, which is caused by the jet stream movement.

Key words: Alpine moors, snow ecology, jet stream, decrease of wetland

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