All issues
Volume 60 (1998)
- Issue 6 Pages 453-
- Issue 5 Pages 349-
- Issue 4 Pages 279-
- Issue 3 Pages 213-
- Issue 2 Pages 131-
- Issue 1 Pages 3-
Volume 60, Issue 5
Displaying 1-5 of 5 articles from this issue
- |<
- <
- 1
- >
- >|
-
Katutosi TUSIMA, Toshihiro KIUCHI1998 Volume 60 Issue 5 Pages 349-356
Published: September 15, 1998
Released on J-STAGE: August 07, 2009
JOURNAL FREE ACCESSIt is known that the friction coefficient of ice is the lowest on the basal plane (0001) of ice. A high-speed skating rink was planned by the control of surface ice crystallography; thirty-six thousands ice plates with the (0001) plane were frozen to the surface ice of the short-track rink at Teisan ice skate trainning rink (Minami maki Village, Nagano). These plates were cut from artificially grown single crystal ice-stalagmites. The friction coefficient of the rink ice was obtained from the measurement of sliding distance of ejected test-skates. The friction coefficient of ice stalagmite rink was 22% less than that of the original surface.View full abstractDownload PDF (9595K) -
Yasuhiro KOMINAMI, Shin-ichi TAKAMI, Kotaro YOKOYAMA, Satoshi INOUE1998 Volume 60 Issue 5 Pages 357-366
Published: September 15, 1998
Released on J-STAGE: February 05, 2010
JOURNAL FREE ACCESSA mathematical model to predict CO2 concentration at the base of a seasonal snowpack was developed. The model was based on the one-dimensional diffusion equation and the wash-down process of CO2 by melt water. Both the snowpack and the underlying soil layer were assumed to be horizontally uniform and infinite. These layers were characterized by their thickness, diffusivities for the CO2, and the flow rates of melt water. The CO2 was assumed to evolve uniformly throughout the soil layer at a constant rate. An implicit finite-difference approximation was used to calculate the temporal change of CO2 at the base of the snowpack. Measurements of CO2 and snowhydrological elements were made for the snowpack over a wheat field in Joetsu, Niigata(37°06'31“N, 138°16'31”E;11m in elevation) in two winters 1990/1991 and 1993/1994. The CO2 concentrations at the ground level were measured continuously with an electrode gas sensor. Two inputs to the model, the depth of snowpack and the flow rate of melt water through the snowpack, were also measured. These inputs, along with the other estimated inputs, were fed into the model to yield the predicted concentrations. Measured CO2 concentration at the base of the snowpack varied between the atmospheric values and about 800 ppmv. The concentration generally increased as the snowpack developed. Superimposed on this slow variation were rapid fluctuations associated with runoff of melt water. The soil temperature at 5cm below the soil surface remained around 0.5°C, so that the runoff of melt water presumably took place almost all the time. Model generally reproduced the measured CO2 concentrations, but occasional disagreement, as much as some hundreds ppmv, were noticed. Discrepancies in slow variations were probably due to the erroneous estimation of the rate of CO2 generation from the soil and the CO2 diffusivity through the snow, whereas spatially heterogeneous downward flow of melt water and the estimation of dissolution coefficient might have produced disagreement in the short-period fluctuations. Nevertheless, this study has provided evidence that melt water plays an important role to determine the CO2 concentration beneath snowpacks occurring in regions where the soil temperature remains above freezing. The proposed model in this study is a useful means to analyze the carbon cycle in terrestrial ecosystems with a seasonal snow cover.View full abstractDownload PDF (1224K) -
Satoshi INOUE, Kotaro YOKOYAMA1998 Volume 60 Issue 5 Pages 367-378
Published: September 15, 1998
Released on J-STAGE: August 07, 2009
JOURNAL FREE ACCESSGlobal climate change may affect significantly on the winter climate of Japan, especially on snow.We estimated the several aspects of snow in Japan, i.e.the snowfall, the maximum snow depth and the condition of snow cover using the changed climate scenarios derived from numerical experiments of general circulation models as the input data.The estimation procedure is, first, to estimate the monthly snowfall by an empirical model using the monthly average temperature and the monthly precipitation as the input data and, secondly, to estimate the maximum snow depth and the condition of snow cover from the monthly mean temperature and statistically estimated snowfall.The estimated results varied according to the geographic location as follows.1)In Hokkaido and at highlands of Honshu Island, no significant change was obtained, but the maximum snow depth decreased.2)In Tohoku district (north-eastern part of Honshu Island)except for highlands, the snowfall and the maximum snow depth decreased considerably.The snow cover condition changed from dry to wet.3)At low elevation areas of the Japan Sea side of Honshu Island south of Hokuriku district, no snowfall occurred and no snow cover was derived.4)Those changes became clear after 50 years from the present.5) The year-to-year variation of snowfall amount became larger around 51 to 75 years later from now in Hokkaido and the northern part of Tohoku district.View full abstractDownload PDF (4910K) -
Koji FUJITA1998 Volume 60 Issue 5 Pages 379-385
Published: September 15, 1998
Released on J-STAGE: August 07, 2009
JOURNAL FREE ACCESS -
new findings at-34°CShinji MAE1998 Volume 60 Issue 5 Pages 387-388
Published: September 15, 1998
Released on J-STAGE: August 07, 2009
JOURNAL FREE ACCESSDownload PDF (301K)
- |<
- <
- 1
- >
- >|