著者

Yoshinori IIZUKA(飯塚芳徳) Sumito MATOBA(的場澄人) Masahiro MINOWA(箕輪昌紘) Tetsuhide YAMASAKI(山崎哲秀) Kaoru KAWAKAMI(川上薫) Ayako KAKUGO(角五綾子) Morihiro MIYAHARA(宮原盛厚) Akihiro HASHIMOTO(橋本明弘) Masashi NIWANO(庭野匡思) Tomonori TANIKAWA(谷川朋範) Koji FUJITA(藤田耕史) Teruo AOKI(青木輝夫)

出版者

THE JAPANESE SOCIETY OF SNOW AND ICE

雑誌

Bulletin of Glaciological Research (ISSN:13453807)

巻号頁・発行日

vol.39, pp.1-12, 2021 (Released:2021-10-13)

参考文献数

18

被引用文献数

2

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In order to construct reliable deposited-aerosol database on the Anthropocene (from 1850 to 2020), we obtained a 250-meter-long ice core from the Southeastern Greenland Dome on May and June 2021, where is one of the highest accumulation domes in Greenland. The age of the ice core at a depth of 250 m was roughly estimated to be AD 1827 based on the timescale from a previously analyzed shallower ice core. The age of the sampled ice core satisfied the prerequisite conditions for constructing aerosol deposition database for Anthropocene. In addition, surface elevation, borehole temperatures, and internal stratigraphy of the ice sheet were performed, and meteorological and snow-pit observations were also conducted. Furthermore, we sampled aerosol and snow from the ice sheet for chemical and physical analyses.

著者

Wataru SHIGEYAMA(繁山航) Naoko NAGATSUKA(永塚尚子) Tomoyuki HOMMA(本間智之) Morimasa TAKATA(高田守昌) Kumiko GOTO-AZUMA(東久美子) Ilka WEIKUSAT Martyn R. DRURY Ernst-Jan N. KUIPER Ramona V. MATEIU Nobuhiko AZUMA(東信彦) Dorthe DAHL-JENSEN Sepp KIPFSTUHL

出版者

公益社団法人 日本雪氷学会

雑誌

Bulletin of Glaciological Research (ISSN:13453807)

巻号頁・発行日

vol.37, pp.31-45, 2019 (Released:2019-12-17)

参考文献数

64

被引用文献数

4

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Mass loss from ice sheets contributes to global sea level rise, and accelerated ice flow to the oceans is one of the major causes of rapid ice sheet mass loss. To understand flow dynamics of polar ice sheets, we need to understand deformation mechanisms of the polycrystalline ice in ice sheets. Laboratory experiments have shown that deformation of polycrystalline ice occurs largely by dislocation glide, which mainly depends on crystal orientation distribution. Grain size and impurities are also important factors that determine ice deformation mechanisms. Compared with ice formed during interglacial periods, ice formed during glacial periods, especially ice that forms cloudy bands, exhibits finer grain sizes and higher impurity concentrations. A previous report suggests the deformation rate of ice containing cloudy bands is higher than that of ice without cloudy bands. To examine the microstructures and deformation histories of ice in cloudy bands, we applied the electron backscatter diffraction (EBSD) technique to samples from the Greenland Ice Sheet using an environmental scanning electron microscope (ESEM) equipped with cold stages. Prior to the EBSD analysis, we optimised our ESEM/EBSD system and performed angular error assessment using artificial ice. In terms of c- and a-axis orientation distributions and grain orientation spread, we found little difference between samples taken from a cloudy band and those taken from an adjacent layer of clear ice. However, subgrain boundary density and orientation gradients were higher in the cloudy band, suggesting that there are more dislocations in the cloudy band than in the clear ice layer.

著者

MATOBA Sumito(的場澄人) MOTOYAMA Hideaki(本山秀明) FUJITA Koji(藤田耕史) YAMASAKI Tetsuhide(山崎哲秀) MINOWA Masahiro(箕輪昌紘) ONUMA Yukihiko(大沼友貴彦) KOMURO Yuki(小室悠紀) AOKI Teruo(青木輝夫) YAMAGUCHI Satoru(山口悟) SUGIYAMA Shin(杉山慎) ENOMOTO Hiroyuki(榎本浩之)

出版者

公益社団法人 日本雪氷学会

雑誌

Bulletin of Glaciological Research (ISSN:13453807)

巻号頁・発行日

vol.33, pp.7-14, 2015 (Released:2015-12-08)

参考文献数

20

被引用文献数

10

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During spring 2014, we drilled an ice core on the northwestern Greenland Ice Sheet, recovering a core of total length 225m. We also conducted stratigraphic observations, measurements of the density of the ice core, near-infrared photography of the ice core, preparation of liquid samples for chemical analysis, and measurements of borehole temperature. The pore close-off depth was 60m, and the temperature in the borehole was −25.6°C at a depth of 10m. In addition, we conducted snow-pit observations, ice-velocity and surface-elevation measurements using the global positioning system (GPS), meteorological observations, and installation of an automated weather station (AWS).

著者

ONUMA Yukihiko(大沼友貴彦) TAKEUCHI Nozomu(竹内望) TAKEUCHI Yukari(竹内由香里)

出版者

公益社団法人 日本雪氷学会

雑誌

Bulletin of Glaciological Research (ISSN:13453807)

巻号頁・発行日

vol.34, pp.21-31, 2016 (Released:2016-09-08)

参考文献数

30

被引用文献数

11

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Snow algae are cold-tolerant photosynthetic microbes growing on snow and ice. In order to investigate the factors affecting snow algal growth, the temporal changes in algal abundance on surface snow were studied over four winters in an experimental station in Niigata Prefecture, Japan, where seasonal snow is usually present from late December to early April. Snow algae appeared on the snow surface in February, and the initial algae were likely to be deposited on the snow by winds. The timing of the algal appearance varied among years, from early-February in 2011 to late-February in 2015, and is likely to be determined by a period of no snowfall and air temperatures above the melting point. Algal abundance generally increased until the disappearance of snow. The maximum algal concentration was found in 2011, which corresponds to the year when the period from algal appearance to the disappearance of snow was the longest (80days) among the four winters. The results suggest that snow algae keep growing unless snowfall occurs and air temperature drops to freezing point, and that the algal abundance is likely to be correlated with the duration of algal growth. The algal growth curve in 2011 could be reproduced by a Malthusian model with a growth rate of 0.22 d−1.

著者

Tsutomu SUDA(須田力) Kazuki TAKIZAWA(瀧澤一騎) Nobuyoshi KONISHI(小西信義) Satoshi OMIYA(大宮哲) Shun TSUTAKI(津滝俊)

出版者

公益社団法人 日本雪氷学会

雑誌

Bulletin of Glaciological Research (ISSN:13453807)

巻号頁・発行日

vol.37, pp.11-21, 2019 (Released:2019-11-08)

参考文献数

17

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The purpose of this study was to examine the physiological responses to intensive snow shoveling. The subjects were six males (25-71, 50±8 years) who participated in a snow removal volunteer tour. Prior to the tour, each subject engaged in a cycle ergometer test (Test 1) and a multistage shoveling test (Test 2) to evaluate the relationship between volume of oxygen consumption (VO2) and heart rate. Field measurements were performed in Miruto of Iwamizawa City, Hokkaido, Japan on February 2, 2014. Average air temperatures of that day were -6.3°C in the morning and -1.4°C in the afternoon. The snow layer at the work site had various grain shapes and snow density linearly increased with snow depth. While snow hardness increased exponentially with increase in snow depth. Mean heart rate during working time in the afternoon (142±9 beats min-1) was significantly (p<0.01) higher than that in the morning (131±9 beats min-1). These heart rates correspond 84% and 77% of the predicted maximum heart rate (HRmax), respectively. Ratings of perceived exertion were not different in the morning (12.9±0.4) and afternoon (12.4±0.3). The mean values of VO2 in the total work period (111±3 min) was estimated to be 22.2±1.2ml kg-1min-1 (Metabolic equivalent; 6.4±0.3METs). Estimated energy expenditure averaged 782±46kcal. It is conceivable that increase in snow hardness and snow density caused an increase in work intensity.