Studies on budget of water vapor and carbon dioxide in Rasyomon doline

测定了罗生门碱的微气象因子（如气温、湿度、气流、光合有效辐射）和植物的生理因子（如光合速率和蒸腾速率）。在峡谷的最低点，侵蚀形成了一个微弱的呼吸，吹洞穴，在温暖的季节排出冷空气。低气压底部的特征是夏季白天温度低于15ºC左右。在整个暖季，doline形成了非常稳定的热层，保持了过湿润的气候，这是苔藓最喜欢的环境。为了弄清从洞穴中流出的空气与洞穴中干燥的关系，我们在1997年夏天两次人工封闭了洞穴最窄的部分。封闭期的空气温度和土壤温度比开放期高3 ~ 4个‰。水汽在封闭期较开放期增加4 ~ 5 hPa。溶洞开放期CO_2浓度约为700 ppm，封闭期CO_2浓度上升至1000 ppm左右。这些结果定量地表明，带有冷但去湿空气的强化空气与石灰石的干燥密切相关。洞穴的关闭也导致了海底CO_2浓度的显著升高，这是苔藓最适宜的生长环境。考虑到这些结果，我们现在计划减少通过洞穴的气流，以防止洞穴干燥，并更新苔藓林。生长在碱底的植物大多具有阴生植物的生理特性，适应了碱底的特定环境。

Micrometeorological factors( such as air temperature, humidity, air flow, and photosynthesis available radiation) and physiological factors of plants ( such as photosynthesis and transpiration rates) were measured in Rasyomon doline. At the lowest point in the doline, erosion created a weak breathing, blowing cavetunnel, draining a cold air in warmer seasons. The bottom in the depression was characterized by daytime summer temperatures below about 15ﾟC.Throughout warm seasons, very stable thermal layer was formed in the doline and it maintained a perhumid climate, which was a favorite environment to mosses.To clarify how the air flow from the cave relates to the drying in the doline, we artificially closed the narrowest section of the cave 2 times in the summer of 1997. Air temperature and soil temperature were higher by 3-4ﾟC in the closed period than in the opened period of cave. However, water, vapor increased by 4-5 hPa in the closed period than that in the opened period. The CO_2 concentration were about 700 ppm in the opened period and increased high levels near 1000 ppm in the closed period of cave. These results demonstrate quantitatively that the strengthned air with a cool but dehumified air is closely related to drying of the doline. The closure of cave also induced a significant rise of CO_2 concentration at the bottom of the doline, which is a favorite environment for mosses to grow. Considering these results, we are now planning to reduce an air flow through the cave to prevent from drying of caveand to renew the moss forest. Most of plants growing at the bottom of the doline had physiological charactersitics of shade plant, adopting to the specific environment of doline.