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.
{"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}
N. Arai, T. Imai, Masaya Otsuki, Yoshihiko Saito, Takahiko Murayama, M. Iwakuni
Infrasound observations can be used to measure the energy radiated by an avalanche into the atmosphere and detect avalanches over large areas. Accompanying significant improvements in avalanche dynamics research, the use of infrasound for avalanche monitoring has increased over the last few decades. Our research team conducted infrasound observations in Tokamachi, Niigata Prefecture, Japan, over the past few winter seasons. In the 2014-2015 winter season, we deployed three sensors spaced by 1-2 km in a triangular array and attempted to automatically extract signals associated with avalanches from the observed raw data using time-domain processing. The locations of avalanches were estimated from the extracted signals using the cross-correlation method. Twelve events were detected and located. The estimated locations were in an area with multiple steep slopes. An infrasound array monitoring system with real-time processing would be capable of providing significant amounts of information concerning avalanche activity in snow-covered regions.
{"title":"Detection of avalanche locations using infrasound array data","authors":"N. Arai, T. Imai, Masaya Otsuki, Yoshihiko Saito, Takahiko Murayama, M. Iwakuni","doi":"10.5331/BGR.16R02","DOIUrl":"https://doi.org/10.5331/BGR.16R02","url":null,"abstract":"Infrasound observations can be used to measure the energy radiated by an avalanche into the atmosphere and detect avalanches over large areas. Accompanying significant improvements in avalanche dynamics research, the use of infrasound for avalanche monitoring has increased over the last few decades. Our research team conducted infrasound observations in Tokamachi, Niigata Prefecture, Japan, over the past few winter seasons. In the 2014-2015 winter season, we deployed three sensors spaced by 1-2 km in a triangular array and attempted to automatically extract signals associated with avalanches from the observed raw data using time-domain processing. The locations of avalanches were estimated from the extracted signals using the cross-correlation method. Twelve events were detected and located. The estimated locations were in an area with multiple steep slopes. An infrasound array monitoring system with real-time processing would be capable of providing significant amounts of information concerning avalanche activity in snow-covered regions.","PeriodicalId":9345,"journal":{"name":"Bulletin of glaciological research","volume":"35 1","pages":"1-6"},"PeriodicalIF":1.0,"publicationDate":"2017-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71025778","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}
M. Furuya, K. Fukui, H. Iida, S. Kojima, T. Matsuoka
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.
{"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}
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.
{"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}
Y. Iizuka, S. Matoba, Tetsuhide Yamasaki, Ikumi Oyabu, Moe Kadota, T. Aoki
{"title":"Glaciological and meteorological observations at the SE-Dome site, southeastern Greenland Ice Sheet","authors":"Y. Iizuka, S. Matoba, Tetsuhide Yamasaki, Ikumi Oyabu, Moe Kadota, T. Aoki","doi":"10.5331/BGR.15R03","DOIUrl":"https://doi.org/10.5331/BGR.15R03","url":null,"abstract":"","PeriodicalId":9345,"journal":{"name":"Bulletin of glaciological research","volume":"3 1","pages":"1-10"},"PeriodicalIF":1.0,"publicationDate":"2016-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71025183","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}
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
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.
本文概述了东西伯利亚Suntar-Khayata山脉31号冰川2012 - 2014年的气象和冰川观测资料。我们在冰川上设置了气象仪器和7个桩，目的是测量地表物质平衡和流速。2012年7月8日—2013年8月7日31-2站点平均气温为-13.9℃(2446 m a.s.l.)，最低气温为-46.0℃。从11月到4月，冰川上的气温比奥伊米亚康村的气温高约10°C，表明存在逆温现象，这种现象通常发生在该地区的冬季。雪深记录显示，冬初和冬末降雪量增加，从10月初到4月底几乎没有变化。2013年5月28日31-2站点积雪深度为158 cm。2012年8月24日至2013年8月16日，6个站点的年平均地表物质平衡为-1256 mm水当量(w.e)，表明冰川所有区域的消融都在快速进行。2013/2014年冰川中点附近的地表流速为1.57 ma，远低于1957/1958年IGY(国际地球物理年)期间的4.5 ma。1958/1959年冰川长度和面积分别为3.85 km和3.2 km, 2012/2013年冰川长度和面积分别为3.38 km和2.27 km, 54年来冰川面积和长度呈减少趋势。
{"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}
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 .
{"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}
S. Matoba, H. Motoyama, K. Fujita, Tetsuhide Yamasaki, M. Minowa, Y. Onuma, Yuki Komuro, T. Aoki, S. Yamaguchi, S. Sugiyama, H. Enomoto
During spring 2014, we drilled an ice core on the northwestern Greenland Ice Sheet, recovering a core of total length 225 m. 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 60 m, and the temperature in the borehole was -25.6 °C at a depth of 10 m. 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).
{"title":"Glaciological and meteorological observations at the SIGMA-D site, northwestern Greenland Ice Sheet","authors":"S. Matoba, H. Motoyama, K. Fujita, Tetsuhide Yamasaki, M. Minowa, Y. Onuma, Yuki Komuro, T. Aoki, S. Yamaguchi, S. Sugiyama, H. Enomoto","doi":"10.5331/BGR.33.7","DOIUrl":"https://doi.org/10.5331/BGR.33.7","url":null,"abstract":"During spring 2014, we drilled an ice core on the northwestern Greenland Ice Sheet, recovering a core of total length 225 m. 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 60 m, and the temperature in the borehole was -25.6 °C at a depth of 10 m. 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).","PeriodicalId":9345,"journal":{"name":"Bulletin of glaciological research","volume":"33 1","pages":"7-14"},"PeriodicalIF":1.0,"publicationDate":"2015-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71027776","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}
Measurements of the concentrations of major ions in the snow pits at Murododaira (altitude, 2,450 m), Mt. Tateyama, near the coast of the Japan Sea in Central Japan, have been taken each April. Snowmelt usually occurs after May near the summit of Mt. Tateyama. However, the snow wall in the 2004 pit was mainly composed of melt forms (granular snow), and snow temperature was 0 ℃ in all layers; therefore, the chemical components in the snow were affected by leaching. Many samples taken from the 2004 pit showed that the ratio of Mg 2 ＋ /Na ＋ was lower than that in sea salt, whereas the loss of Mg 2 ＋ has hardly been observed in the snow cover at Murododaira in other years. The results suggest that the Mg 2 ＋ /Na ＋ ratio can be used as an indicator of the leaching of chemical compositions in a snowpack, such as a boring core, at an Alpine site in Japan.
{"title":"Ratios of Mg2+/Na+ in the snow cover at Murododaira, Mt. Tateyama, Japan: On the possibility of an indicator of chemical leaching","authors":"Koichi Watanabe, Taiki（平井泰貴） Hirai, K. Kawada","doi":"10.5331/BGR.33.1","DOIUrl":"https://doi.org/10.5331/BGR.33.1","url":null,"abstract":"Measurements of the concentrations of major ions in the snow pits at Murododaira (altitude, 2,450 m), Mt. Tateyama, near the coast of the Japan Sea in Central Japan, have been taken each April. Snowmelt usually occurs after May near the summit of Mt. Tateyama. However, the snow wall in the 2004 pit was mainly composed of melt forms (granular snow), and snow temperature was 0 ℃ in all layers; therefore, the chemical components in the snow were affected by leaching. Many samples taken from the 2004 pit showed that the ratio of Mg 2 ＋ /Na ＋ was lower than that in sea salt, whereas the loss of Mg 2 ＋ has hardly been observed in the snow cover at Murododaira in other years. The results suggest that the Mg 2 ＋ /Na ＋ ratio can be used as an indicator of the leaching of chemical compositions in a snowpack, such as a boring core, at an Alpine site in Japan.","PeriodicalId":9345,"journal":{"name":"Bulletin of glaciological research","volume":"33 1","pages":"1-5"},"PeriodicalIF":1.0,"publicationDate":"2015-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71027498","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}
T. Aoki, S. Matoba, J. Uetake, Nozomu Takeuchi, Hideaki Motoyama
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.
{"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}
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