Journal of the Japanese Society of Snow and Ice
Online ISSN : 1883-6267
Print ISSN : 0373-1006
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Volume 71, Issue 4
Displaying 1-4 of 4 articles from this issue
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  • Characteristics of ground freezing and thawing under snow cover based on long-term observation
    Yusuke HARADA , Fujio TSUCHIYA, Kazuo TAKEDA, Toshimi MUNEOKA
    2009 Volume 71 Issue 4 Pages 241-251
    Published: 2009
    Released on J-STAGE: April 09, 2021
    DOIhttps://doi.org/10.5331/seppyo.71.4_241
    JOURNAL OPEN ACCESS
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    Observations of frost and snow depths were conducted at the Obihiro University site located in eastern Hokkaido, Japan, from November 1981 to April 2007, and the characteristics of ground freezing and thawing under snow cover were analyzed. The results indicated that the annual maximum frost depth ranged from 5 to 55cm during the 26 winters. Frost depth is influenced by seasonal changes in snow depth, and it was confirmed that it is proportional to the square root of the freezing index when snow depth reaches 20cm. The thawing of frozen ground starts from the surface at the seasonal end of snow cover and finishes from late March to early May (last frost day). A linear relationship was found between the vanishing frost depth and the maximum frost depth. Further, the vanishing frost depth was found to be proportional to the square root of the thawing index. Based on these findings, the seasonal maximum frost depth, vanishing frost depth, and last frost day were calculated using meteorological data from 1961 to 1980 obtained from Obihiro Meteorological Observatory. Taken together, we can conclude that the annual maximum frost depth has decreased in the last half century and that the last frost day has shifted from mid to early April.
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  • Chemical characterization of snowfall in Shinjo, Yamagata Prefecture, Japan and long-term trend of snow acidification during 1991/92 to 2002/03
    Naofumi AKATA, Fumitaka YANAGISAWA , Nobutaka OKUMURA , Shin'ichir ...
    2009 Volume 71 Issue 4 Pages 253-262
    Published: 2009
    Released on J-STAGE: April 09, 2021
    DOIhttps://doi.org/10.5331/seppyo.71.4_253
    JOURNAL OPEN ACCESS
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    In order to identify the characteristic chemical composition of falling snow in Shinjo, we collected snow samples during four winter seasons (from 1999/00 to 2002/03), and measured their pH, EC and major ionic components. More than 70 ％ of the snow samples were acid snow with pH less than 5.0.The average range of pH was from 4.7 to 4.9 in each year. The concentration of sea-salt components (Na+ and Cl-)tended to rise in the strong northwest winter monsoon. The nssSO4 2- concentration of samples were slightly higher than NO3- concentration. The nssCa2+/NO3- ratios suggested that NO3- mainly originated from nearby areas, while nssSO4 2- was transported from the Asian continent. The nssCa2+ concentration were increased depending on the influence of airborne yellow sand. Moreover, falling snow in Shinjo became more acidified year to year during 1991 to 2003, and we determined it was highly possible that snow acidification was influenced mainly by elevated NO3- concentration.
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  • Snow crystal formation experiments at Kitami Institute of Technology as a course element in “Experiments of Fundamental Physics”
    TAKAO KAMEDA, Kazutaka TATEYAMA, Kinji HYAKUTAKE , Shuhei TKAHASHI, Hi ...
    2009 Volume 71 Issue 4 Pages 263-272
    Published: 2009
    Released on J-STAGE: April 09, 2021
    DOIhttps://doi.org/10.5331/seppyo.71.4_263
    JOURNAL OPEN ACCESS
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    Snow crystal formation experiments have been conducted as an element of the “Experiments of Fundamental Physics” course at Kitami Institute of Technology (KIT) since October 2006. The course is a required subject for freshmen at KIT. Most of the freshmen (410 persons per year) have performed the experiment, with a total of 1000 students by January 2009. The remarkable feature of this experiment is that eight students can simultaneously form snow crystals using eight sets of experimental apparatus. A commercial “experimental apparatus for snow crystal formation” product from Toyo Engineering Works Ltd. was used. This paper describes the experimental apparatus, the snow crystals and experimental conditions at KIT. This paper may assist readers interested in introducing experiments in snow crystal formation into classrooms in schools and universities.
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  • Model to evaluate avalanche riskful slopes from slope features
    Minoru AKIYAMA, Hiroshi P． SATO, Mamoru KOARAI, Hiroyuki HASEGAWA, ...
    2009 Volume 71 Issue 4 Pages 273-281
    Published: 2009
    Released on J-STAGE: April 09, 2021
    DOIhttps://doi.org/10.5331/seppyo.71.4_273
    JOURNAL OPEN ACCESS
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    [in Japanese]
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