Journal of the Japanese Society of Snow and Ice
Online ISSN : 1883-6267
Print ISSN : 0373-1006
Volume 67, Issue 2
Displaying 1-6 of 6 articles from this issue
  • Tetsuyuki ISHII, Hideaki MIYAMOTO, Sho SASAKI
    2005 Volume 67 Issue 2 Pages 123-132
    Published: March 15, 2005
    Released on J-STAGE: August 07, 2009
    JOURNAL FREE ACCESS
    Although the existence of liquid water on Mars cannot be expected under its present dry and thin atmospheric conditions, observations of the recent Martian gully-like features associated with fluid flows suggest the existence of liquid water on or near the surface of Mars. However, if Martian gullies were not formed in the recent past but are forming even today, liquid water would not be responsible for the formation of the gullies. CO2 is the most volatile element prevalent on Mars; and it condenses on the ground surface as seasonal frost with a decrease in the ground surface temperature. Certain MOC images in springtime show views of possible avalanches of CO2 frost on the walls of the polar pits, and suggest that the CO2 avalanches, such as powder flows or granular flows, could possibly dissect local slopes and develop gullies. In this study, we calculate the thickness of the CO2 frost condensed on local slopes as a function of latitude and obliquity by using an energy balance model that takes into consideration the effects of the local slopes. The results show a significant correlation between the latitudinal distribution of the orientations of gullied slopes and that of the slopes covered with seasonal CO2 frost.
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  • Takasumi KURAHASHI, Eiichi TAJIKA, Takasumi KURAHASHI-NAKAMURA
    2005 Volume 67 Issue 2 Pages 133-145
    Published: March 15, 2005
    Released on J-STAGE: February 05, 2010
    JOURNAL FREE ACCESS
    The present climate of Mars is extremely cold and dry and is characterized by an extremely thin CO2 atmosphere. However, geological evidence suggests that the Martian climate in the past might have been warm and wet. If this were the case, the atmospheric CO2 pressure would have been several bars higher. Our numerical study suggests that permanent CO2 ice caps (CO2 ice sheets) would have played an important role in the evolution of Mars from having a warm climate with a dense CO2 atmosphere to the present cold climate. Owing to the instability of the CO2 system, which was triggered by impact erosion and/or sputtering of the atmosphere, the dense CO2 atmosphere should have collapsed to form large polar caps. The collapse corresponds to a runaway condensation of the atmospheric CO2 into large CO2 ice caps (climate jump). Our investigation of the CO2 ice caps by using an ice sheet model suggests that the temperature at the bottom of the CO2 ice cap would exceed the melting point of CO2 due to the geothermal heat flux prevalent in Mars. In that case, gaseous or liquid CO2 produced by basal melting might have permeated and diffused into the subsurface through the pores of the Martian crust. It is possible that the CO2 removed from the surface presently exists in the Martian subsurface as clathrate, carbonate, and/or liquid and gaseous phases.
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  • Masahiko AKAWA
    2005 Volume 67 Issue 2 Pages 147-154
    Published: March 15, 2005
    Released on J-STAGE: August 07, 2009
    JOURNAL FREE ACCESS
  • Masatsugu ODAKA
    2005 Volume 67 Issue 2 Pages 155-162
    Published: March 15, 2005
    Released on J-STAGE: February 05, 2010
    JOURNAL FREE ACCESS
    Recent spacecraft observations bring a lot of Martian meteorological data to us and then quantitative study on ice clouds in the Martian atmosphere are now beginning to be challenged by using that observational data.
    Distribution of the water ice cloud is useful for an index of large scale atmospheric circulation which can not be observe directly, since the Martian water ice cloud can be treated as an atmospheric passive tracer. The Martian carbon dioxide ice cloud over the polar night region, which has not been observed directly by previous instruments, is observed directly by the Mars Orbiter Laser Altimeter carried on the Mars Global Surveyor. It is also important for study on early Mars climate, since the carbon dioxide ice cloud may contribute to warm and moist climate in early Mars owing to its scattering property of infrared radiation. Investigation of formation processes of the carbon dioxide ice cloud and its radiative properties would find a clue to understanding of present and early Mars climate.
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  • Flow-generated landforms by water and ice
    Takanobu SAWAGAKI, Kotaro FUKUI, Shuji IWATA
    2005 Volume 67 Issue 2 Pages 163-178
    Published: March 15, 2005
    Released on J-STAGE: August 07, 2009
    JOURNAL FREE ACCESS
    Recent images from a series of NASA's and ESA's Mars spacecraft missions have provided greater details of the Martian landscape. At present, the surface of Mars is extremely cold and dry; a similar environment on Earth is the so-called “polar desert”. Landforms of the inland mountains of Antarctica are generally regarded as the best analogous forms to those on Mars. Large-scale fluvial landforms on Mars, which suggest that liquid water once flowed on the surface, have been recognized. Furthermore, topographic forms similar to glacial or periglacial origins on Earth have been suggested to occur on Mars. However, the criteria for the formation of rock glaciers and debris-covered glaciers on Earth are not directly applicable to those on Mars. The debris covers of the glaciers on Mars are possibly formed in a manner similar to the formation of the sublimation till cover found in Antarctica.
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  • Masayoshi SUGIMORI, Yoshimi KAWAMOTO, Yoshiaki HONDA
    2005 Volume 67 Issue 2 Pages 179-189
    Published: March 15, 2005
    Released on J-STAGE: August 07, 2009
    JOURNAL FREE ACCESS
    In this paper, we investigate the matter of the 20th heavy snow in Showa era in the Fukui district by means of newspaper articles. We aim at maintaining records of this matter and analyzing the interaction between snowfall and the social state. At that time, the maximum snow depth was 161cm, and the snowfall ranked as the 5th heaviest one on record.
    Historically, we were under a very unusual period—the last stage of the Pacific War. A total of 145 articles, even those remotely related to the snowfall, were collected. In order to analyze the snowfall, the articles were classified by five main attributes, namely, district, reason (relation to the snowfall), content, hero (key person in the articles), and motivation (to cite as news). Further, cross classification among these main attributes was carried out. The classification by reason is as follows: snow disaster (6.2), snow removal (35.2), prevention of snow (4.8), social matters caused by snowfall (17.2), and social matters arising under the circumstances of snowfall (35.2); figures within parentheses indicate the percentage of occurrences. With regard to content, the percentages of occurrences were in the following order: railways, habitants and roads, agriculture, forestry, and so on, while those for hero was residents, administration, schoolchildren, and so on. Further, labor service, communication, and diligence in work comprise the majority for motivation. For example, most of the articles regarding snow removal from railways rarely dealt with the suspension of trains but praised residents or schoolchildren for their grueling labor services toward snow removal. Thus, it is evident that the social state at that time was greatly reflected in the newspaper articles pertaining to snowfall.
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