巻号一覧
81 巻 (2019)
- 6 号 p. 269-
- 5 号 p. 231-
- 4 号 p. 151-
- 2 号 p. 67-
前身誌
81 巻, 6 号
選択された号の論文の3件中1～3を表示しています
- |<
- <
- 1
- >
- >|
-
上村 靖司, 善哉 広大2019 年 81 巻 6 号 p. 269-281
発行日: 2019年
公開日: 2020/10/19
ジャーナル オープンアクセスTo evaluate the overall performance of road surface snow-melting devices, two indexes, one focusing on service level and the other focusing on heat consumption, are proposed. For the service level index, the “snow remaining time ratio”，ϕ，is defined as the ratio of the total snow remaining time on the surface to the total snowfall time during a winter season. As the overall heat consumption index, the “input heat ratio”，E, is defined as the ratio of the total heat output of the snow melting device to the total heat load created by snowfall in a winter season. In our study, a snowmelt simulation was performed by inputting the weather data of five winters in Japan at six representative points into the heat balance model proposed in our previous report. Three types of operation methods (snowfall detection control (FC), snow cover detection control (CC), and hybrid control (HC)), as well as two heat output control types (constant and variable) were simulated, and a ϕ-E diagram was created for each model. The ϕ-E diagram, which is useful for determining a balance between service levels and the operating costs, can also provide a guide of the initial setup costs. A comparison between the three operation methods revealed the following points. The high heat output of the FC method provides high service levels that rarely leave residual snow when the snowfall duration is short. In contrast, in the CC method, heat consumption is less than half that of FC, but there is a limit to the service level that can be achieved via that method. In the case of the HC method, high service can be realized with low heat output and a heat consumption that is intermediate between the FC and CC methods. Meanwhile, we found that variable heat output is effective in terms of both service and heat consumption levels, but it does not lead to dramatic improvements despite higher initial costs. In particular, combining variable heat output with the CC method does not produce any notable advantages.抄録全体を表示PDF形式でダウンロード (2275K) -
有江 賢志朗, 奈良間 千之, 福井 幸太郎, 飯田 肇, 高橋 一徳2019 年 81 巻 6 号 p. 283-295
発行日: 2019年
公開日: 2020/10/19
ジャーナル フリーWe performed ground penetrating radar and global navigation satellite system surveys to investigate the ice thickness and flow of the Karamatsuzawa perennial snow patch, at the village of Hakuba, Nagano Prefecture. The field survey showed that the perennial snow patch contained an ice mass with a thickness greater than 30m and the ice flowed in the slope direction at a rate of 250mm over a 29-day period in the late snow-melting season in 2018. Based on the observed ice thickness and motion, the Karamatsuzawa perennial snow patch was recognised as an active glacier. The observed ice motion was significantly greater than the internal ice deformation estimated using Glenʼs Flow Law. This implies that basal sliding contributes to the motion of the Karamatsuzawa perennial snow patch.抄録全体を表示PDF形式でダウンロード (5497K) -
梨本 真2019 年 81 巻 6 号 p. 297-314
発行日: 2019年
公開日: 2020/10/19
ジャーナル オープンアクセス富士山における雪崩がノウサギの採餌環境の創出に果たしている役割を明らかにするため，1945年，1980年，1992 年のスラッシュ雪崩で森林が破壊され，カラマツによる再生が進む3つの雪崩地で，ノウサギの出現状況と餌資源の変化を18 年間にわたって調査した．雪崩発生8 年後の雪崩地に排泄された糞粒数は隣接する森林の10倍（非積雪期）から19倍（積雪期）で，ノウサギは雪崩地を餌場として利用し，非積雪期には好陽性草本，積雪期にはカラマツなどの低木を採食していた．糞粒法で推定した生息密度は，雪崩発生22年後の雪崩地で0.18頭ha −1（積雪期），35年後の雪崩地で0.01頭ha −1（同）で，70年後の雪崩地は利用していなかった．雪崩地の餌資源と積雪深の変化から推定した採餌環境としての利用可能期間はおよそ25〜35 年で，生息密度の変化を裏付けていた．一方，雪崩の再来間隔が短い（1.6〜6 年）雪崩地は植生遷移が停滞しているため，ノウサギの採餌環境としての植物群落が永続的に維持されている．富士山で発生する再来間隔と規模の異なる雪崩は，雪崩撹乱後の植生動態，ノウサギの採食生態，積雪深の変化と密接に関連して，ノウサギの多様な採餌環境の創出に寄与している．抄録全体を表示PDF形式でダウンロード (6615K)
- |<
- <
- 1
- >
- >|