Bulletin of glaciological research最新文献_第3页

Scanning electron microscopic studies on the methane hydrate decomposition using the freeze-fracture replica method 冻裂复刻法对甲烷水合物分解的扫描电镜研究

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Bulletin of glaciological research Pub Date : 2017-01-01 DOI: 10.5331/BGR.17R02

Ayumi Fujimoto, T. Sugahara

{"title":"Scanning electron microscopic studies on the methane hydrate decomposition using the freeze-fracture replica method","authors":"Ayumi Fujimoto, T. Sugahara","doi":"10.5331/BGR.17R02","DOIUrl":"https://doi.org/10.5331/BGR.17R02","url":null,"abstract":"It is well known that methane hydrate exhibits abnormal stability, so-called “self-preservation eﬀect” at temperatures of 240 K to 270 K and atmospheric pressure, though the equilibrium temperature of methane hydrate at atmospheric pressure is approximately 190 K. The ice shielding at the surface of methane hydrate would be one of the most important steps toward developing the self-preservation. That is, to observe the phase and morphology changes from methane hydrate to ice is signiﬁcant. We have observed the microstructural change of the synthetic methane hydrate during its decomposition at the temperatures of 263 K and 293 K with a combination of scanning electron microscopy (SEM) and the freeze-fracture replica method. The SEM images reveal that the methane hydrate crystal has a structure arranging the clusters of 20 nm in diameter. When the methane hydrate is partially decomposed during taken from the high-pressure cell (rapid depressurization at 253 K), a part of the clusters changes to the cluster aggregates of 60‒200 nm. The cluster aggregates gradually grow from their peripheries to the hexagonal ice crystals during gradual decomposition at 263 K. The microstructural change supports the decomposition mechanism of methane hydrate by ice-shielding under a temperature condition with self-preservation eﬀect. At 293 K, the methane hydrate is immediately decomposed. The residual aqueous solution after complete decomposition contains the large number of ultraﬁne bubbles (nanobubbles) of 100 nm or less in diameter.","PeriodicalId":9345,"journal":{"name":"Bulletin of glaciological research","volume":"35 1","pages":"39-45"},"PeriodicalIF":1.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5331/BGR.17R02","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71025589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 6

Detection of avalanche locations using infrasound array data 利用次声阵列数据探测雪崩位置

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Bulletin of glaciological research Pub Date : 2017-01-01 DOI: 10.5331/BGR.16R02

N. Arai, T. Imai, Masaya Otsuki, Yoshihiko Saito, Takahiko Murayama, M. Iwakuni

引用次数: 1

Experimental Observations of Two Mountain Glaciers on the Eastern Slope of Mt. Tsurugi by Pi-SAR2 Airborne SAR 鹤木山东坡两座高山冰川的Pi-SAR2机载SAR实验观测

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Bulletin of glaciological research Pub Date : 2017-01-01 DOI: 10.5331/BGR.16R04

M. Furuya, K. Fukui, H. Iida, S. Kojima, T. Matsuoka

{"title":"Experimental Observations of Two Mountain Glaciers on the Eastern Slope of Mt. Tsurugi by Pi-SAR2 Airborne SAR","authors":"M. Furuya, K. Fukui, H. Iida, S. Kojima, T. Matsuoka","doi":"10.5331/BGR.16R04","DOIUrl":"https://doi.org/10.5331/BGR.16R04","url":null,"abstract":"We performed airborne synthetic aperture radar (SAR) observations at two glaciers (San’nomado and Komado glaciers) on the eastern slope of Mt. Tsurugi, Japan, in August and October 2013, and August 2014. The Pi-SAR2 system used in this study consists of two X-band SAR antennas. Taking advantage of single-pass interferometry, we have generated digital elevation models (DEM) at each epoch. Differencing the DEMs at August and October 2013, the elevations at the glaciers were reduced by ~20 m or more with errors on the order of ~20 m or more. As we could visually identify the reduction in the snow-covered areas in the SAR images of August and October 2013, those changes are attributable to seasonal melting of the snow but are apparently overestimated. Full polarimetric observations were also performed, indicating significant changes over the glaciers from August to October that were largely due to the reduction in snow cover. We could further identify localized spots that indicated strong intensity in the cross-polarized HV channel (transmission of vertically polarized wave and reception in horizontally polarized channel) over the glaciers. Bright HV signals are unexpected, because HV signals are often interpreted as volume scattering and appear to originate from the inside of the glaciers that are unlikely in the X-band SAR system; no penetration deeper than 1 m is expected in the X-band over the snow/ice areas. We interpret the apparent HV signals as due to double bouncing from both sides of the valley, which were apparently imaged over the glaciers.","PeriodicalId":9345,"journal":{"name":"Bulletin of glaciological research","volume":"35 1","pages":"7-17"},"PeriodicalIF":1.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71025986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Glacier variations of Hielo Patagónico Norte, Chile, over 70 years from 1945 to 2015 1945 - 2015年70年间智利北部Hielo Patagónico冰川变化

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Bulletin of glaciological research Pub Date : 2017-01-01 DOI: 10.5331/BGR.17R01

M. Aniya

{"title":"Glacier variations of Hielo Patagónico Norte, Chile, over 70 years from 1945 to 2015","authors":"M. Aniya","doi":"10.5331/BGR.17R01","DOIUrl":"https://doi.org/10.5331/BGR.17R01","url":null,"abstract":"Hielo Patagónico Norte (HPN, or Northern Patagonia Icefield) is located in the southern part of Chile with an area of ca. 4200 km in 1975 and 3950 km in 2000. Variations of 21 major outlet glaciers in 70 years from 1945 to 2015 were documented in detail using aerial photographs and aerial survey photographs. The HPN lost an area of 126.73 km or ca. 3 % of the total area of 1975 due to glacier snout recessions. The largest loss was at Glaciar (Gl.) San Quintin (the largest glacier in the HPN) with 40.68 km. The four largest glaciers including Gl. San Rafael, Steffen and Reicher together account for 57.5 % of all the loss. The smallest area loss was 0.46 km at Gl. Arco. In terms of distance retreated, southwest snout of Gl. Reicher is the largest with 6350 m. The smallest retreat was ca. 350 m at Gl. León. While the trend was retreat in general, eight glaciers made advances although ephemeral, with some glaciers a few times. Snout disintegration was observed at eight glaciers, which was often preceded by advance. Gl. San Quintin and Steffen had seven snout disintegrations each since 1990. The east-west and north-south contrasts in glacier variations are very pronounced: glaciers on the west side and the north side lost substantially more than those on the east side and the south side, respectively. In this study period, glacial-lake outburst floods (GLOFs) were recognized at three glaciers and one moraine-dammed lake.","PeriodicalId":9345,"journal":{"name":"Bulletin of glaciological research","volume":"35 1","pages":"19-38"},"PeriodicalIF":1.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5331/BGR.17R01","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71025917","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 9

Glaciological and meteorological observations at the SE-Dome site, southeastern Greenland Ice Sheet 格陵兰岛冰盖东南部SE-Dome站点的冰川和气象观测

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Bulletin of glaciological research Pub Date : 2016-01-26 DOI: 10.5331/BGR.15R03

Y. Iizuka, S. Matoba, Tetsuhide Yamasaki, Ikumi Oyabu, Moe Kadota, T. Aoki

引用次数: 14

Meteorological and glaciological observations at Suntar-Khayata Glacier No. 31, east Siberia, from 2012-2014 2012-2014年东西伯利亚Suntar-Khayata冰川31号的气象和冰川观测

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Bulletin of glaciological research Pub Date : 2016-01-01 DOI: 10.5331/BGR.16R01

T. Shirakawa, T. Kadota, A. Fedorov, P. Konstantinov, Takafumi Suzuki, H. Yabuki, F. Nakazawa, Sota Tanaka, Masaya Miyairi, Y. Fujisawa, N. Takeuchi, Ryo Kusaka, Shuhei Takahashi, H. Enomoto, T. Ohata

{"title":"Meteorological and glaciological observations at Suntar-Khayata Glacier No. 31, east Siberia, from 2012-2014","authors":"T. Shirakawa, T. Kadota, A. Fedorov, P. Konstantinov, Takafumi Suzuki, H. Yabuki, F. Nakazawa, Sota Tanaka, Masaya Miyairi, Y. Fujisawa, N. Takeuchi, Ryo Kusaka, Shuhei Takahashi, H. Enomoto, T. Ohata","doi":"10.5331/BGR.16R01","DOIUrl":"https://doi.org/10.5331/BGR.16R01","url":null,"abstract":"This paper outlines meteorological and glaciological observations of Glacier No. 31 in the Suntar-Khayata Range, east Siberia, obtained from 2012 to 2014. We set up meteorological instruments and seven stakes on the glacier for the purpose of measuring surface mass balance and flow velocity. The mean air temperature between July 8, 2012 and August 7, 2013 was -13.9°C at site 31–2 (2446 m a.s.l.) and the minimum temperature was -46.0°C. The air temperature on the glacier from November to April was approximately 10°C higher than that at Oymyakon village, suggesting a temperature inversion phenomenon, which typically occurs during winter in this region. The snow depth records show that snow increased at the beginning and end of winter, and that there was almost no change from the beginning of October until the end of April. The maximum snow depth from the previous summer was 158 cm at site 31–2 on May 28, 2013. The average annual surface mass balance for the 6 sites was -1256 mm water equivalent (w.e.) during the period from August 24, 2012 to August 16, 2013, indicating that ablation proceeded rapidly in all areas of the glacier. Surface flow velocity in 2013/2014 was 1.57 ma at the approximate midpoint of the glacier, and was much slower than that measured during the IGY (International Geophysical Year) period (4.5 ma) in 1957/1958. The length and areal extent of the glacier were 3.85 km and 3.2 km in 1958/1959 and 3.38 km and 2.27 km in 2012/2013, respectively, showing a decrease over the last 54 years.","PeriodicalId":9345,"journal":{"name":"Bulletin of glaciological research","volume":"34 1","pages":"33-40"},"PeriodicalIF":1.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5331/BGR.16R01","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71025969","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 7

Temporal changes in snow algal abundance on surface snow in Tohkamachi, Japan 日本富町地区地表雪藻丰度的时间变化

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Bulletin of glaciological research Pub Date : 2016-01-01 DOI: 10.5331/BGR.16A02

Y. Onuma, N. Takeuchi, Y. Takeuchi

{"title":"Temporal changes in snow algal abundance on surface snow in Tohkamachi, Japan","authors":"Y. Onuma, N. Takeuchi, Y. Takeuchi","doi":"10.5331/BGR.16A02","DOIUrl":"https://doi.org/10.5331/BGR.16A02","url":null,"abstract":"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 (80 days) 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 .","PeriodicalId":9345,"journal":{"name":"Bulletin of glaciological research","volume":"34 1","pages":"21-31"},"PeriodicalIF":1.0,"publicationDate":"2016-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71025673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 10

Glaciological and meteorological observations at the SIGMA-D site, northwestern Greenland Ice Sheet 格陵兰冰盖西北部SIGMA-D站点的冰川和气象观测

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Bulletin of glaciological research Pub Date : 2015-11-10 DOI: 10.5331/BGR.33.7

S. Matoba, H. Motoyama, K. Fujita, Tetsuhide Yamasaki, M. Minowa, Y. Onuma, Yuki Komuro, T. Aoki, S. Yamaguchi, S. Sugiyama, H. Enomoto

引用次数: 10

Ratios of Mg2+/Na+ in the snow cover at Murododaira, Mt. Tateyama, Japan: On the possibility of an indicator of chemical leaching 日本立山山murrodoaira积雪中Mg2+/Na+的比值:化学淋滤指标的可能性

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Bulletin of glaciological research Pub Date : 2015-01-01 DOI: 10.5331/BGR.33.1

Koichi Watanabe, Taiki（平井泰貴） Hirai, K. Kawada

引用次数: 2

Field activities of the "Snow Impurity and Glacial Microbe effects on abrupt warming in the Arctic" (SIGMA) Project in Greenland in 2011-2013（2011-2013年グリーンランドにおけるSIGMAプロジェクトの野外活動報告） Field activities of the "Snow Impurity and Glacial Microbe effects on abrupt warming in the Arctic"SIGMA计划2011-2013 (SIGMA计划2011-2013年格陵兰野外活动报告)

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Bulletin of glaciological research Pub Date : 2014-08-01 DOI: 10.5331/BGR.32.3

T. Aoki, S. Matoba, J. Uetake, Nozomu Takeuchi, Hideaki Motoyama

{"title":"Field activities of the \"Snow Impurity and Glacial Microbe effects on abrupt warming in the Arctic\" (SIGMA) Project in Greenland in 2011-2013（2011-2013年グリーンランドにおけるSIGMAプロジェクトの野外活動報告）","authors":"T. Aoki, S. Matoba, J. Uetake, Nozomu Takeuchi, Hideaki Motoyama","doi":"10.5331/BGR.32.3","DOIUrl":"https://doi.org/10.5331/BGR.32.3","url":null,"abstract":"Field activities of the “Snow Impurity and Glacial Microbe effects on abrupt warming in the Arctic” (SIGMA) Project in Greenland in the summer season of 2011-2013 are reported; this consists of (1) glaciological and meteorological observations and (2) biological observations. In 2011, we conducted a field reconnaissance in the Qaanaaq, Ilulissat and Kangerlussuaq areas to enable continuous meteorological observations with automatic weather stations (AWS), campaign observations for glaciology, meteorology and Biology and shallow ice core drilling, which were planned for 2012-2014. Based on the results, we chose the Qaanaaq area in northwest Greenland as our main activity area and the Kangerlussuaq area in mid-west Greenland partly for biological observations. In 2012, we conducted field observations for (1) and (2) mentioned above together with installations of two AWSs at site SIGMA-A on The Greenland ice sheet (GrIS) and at site SIGMA-B on the Qaanaaq ice cap (QIC) from June to August. Surface snow and ice over all of the QIC melted in July and August 2012, and most of the Glacier surface appeared to be dark-colored, probably due to mineral dust and glacial microbial products. In 2013, we carried out similar observations in the Qaanaaq area. However, the weather and Glacier surface conditions were considerably different from those in 2012. Snow cover over the summer of 2013 remained over large areas with elevations higher than about 700 m on QIC. Biological activity on the Glacier surface appears to be substantially lower as compared to that in 2012.","PeriodicalId":9345,"journal":{"name":"Bulletin of glaciological research","volume":"32 1","pages":"3-20"},"PeriodicalIF":1.0,"publicationDate":"2014-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71027116","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 39