A. Hachikubo, S. Yamaguchi, H. Arakawa, T. Tanikawa, M. Hori, K. Sugiura, S. Matoba, M. Niwano, K. Kuchiki, T. Aoki
The specific surface area (SSA) of snow is of particular interest to researchers because SSA is strongly related to snow albedo and is a comparatively better indicator of snowʼs complexity than grain size. The time variation of SSA for fresh snow samples was observed in the laboratory under isothermal conditions at 226 K and 254 K using the gas adsorption method and Brunauer‒Emmett‒Teller theory. The SSA of the snow samples decreased with time under isothermal metamorphism. The decrease in SSA was fitted with the logarithmic equation proposed by Legagneux et al. (2003), and adjustable parameters were obtained. The rate of decrease in SSA depended on the shape of the initial snow type and temperature. Dendritic snow samples exhibited large initial SSAs, and their SSAs decreased faster compared with those of fragmented (collected from drifting snow) and plate-like precipitation particles with relatively small initial SSAs. The rate of decrease in SSA was lower at 226 K than that at 254 K.
{"title":"Effects of temperature and grain type on time variation of snow specific surface area","authors":"A. Hachikubo, S. Yamaguchi, H. Arakawa, T. Tanikawa, M. Hori, K. Sugiura, S. Matoba, M. Niwano, K. Kuchiki, T. Aoki","doi":"10.5331/BGR.32.47","DOIUrl":"https://doi.org/10.5331/BGR.32.47","url":null,"abstract":"The specific surface area (SSA) of snow is of particular interest to researchers because SSA is strongly related to snow albedo and is a comparatively better indicator of snowʼs complexity than grain size. The time variation of SSA for fresh snow samples was observed in the laboratory under isothermal conditions at 226 K and 254 K using the gas adsorption method and Brunauer‒Emmett‒Teller theory. The SSA of the snow samples decreased with time under isothermal metamorphism. The decrease in SSA was fitted with the logarithmic equation proposed by Legagneux et al. (2003), and adjustable parameters were obtained. The rate of decrease in SSA depended on the shape of the initial snow type and temperature. Dendritic snow samples exhibited large initial SSAs, and their SSAs decreased faster compared with those of fragmented (collected from drifting snow) and plate-like precipitation particles with relatively small initial SSAs. The rate of decrease in SSA was lower at 226 K than that at 254 K.","PeriodicalId":9345,"journal":{"name":"Bulletin of glaciological research","volume":"32 1","pages":"47-53"},"PeriodicalIF":1.0,"publicationDate":"2014-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71027319","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, Tetsuhide Yamasaki, Morihiro Miyahara, H. Motoyama
To determine the transport processes of water vapor and aerosols over the northwestern Greenland ice sheet, we undertook a glaciological observation at a coastal site on the northwestern part of the ice sheet and revealed spatial variations in δ 18 O and in the concentrations of chemical substances in surface snow and the snowpack. On the outlet glacier (the Meehan glacier), water vapor and sea salt were transported from the coast. On the inland ice sheet in northwestern Greenland, water vapor, mineral dust, anthropogenic substances such as NO 3 - and SO4 2- , and CH3SO3 - from marine phytoplankton were transported from the west coast of Greenland via the central part of the Greenland ice sheet. 18 O, ion species
{"title":"Spatial variations of δ18O and ion species in the snowpack of the northwestern Greenland ice sheet","authors":"S. Matoba, Tetsuhide Yamasaki, Morihiro Miyahara, H. Motoyama","doi":"10.5331/BGR.32.79","DOIUrl":"https://doi.org/10.5331/BGR.32.79","url":null,"abstract":"To determine the transport processes of water vapor and aerosols over the northwestern Greenland ice sheet, we undertook a glaciological observation at a coastal site on the northwestern part of the ice sheet and revealed spatial variations in δ 18 O and in the concentrations of chemical substances in surface snow and the snowpack. On the outlet glacier (the Meehan glacier), water vapor and sea salt were transported from the coast. On the inland ice sheet in northwestern Greenland, water vapor, mineral dust, anthropogenic substances such as NO 3 - and SO4 2- , and CH3SO3 - from marine phytoplankton were transported from the west coast of Greenland via the central part of the Greenland ice sheet. 18 O, ion species","PeriodicalId":9345,"journal":{"name":"Bulletin of glaciological research","volume":"32 1","pages":"79-84"},"PeriodicalIF":1.0,"publicationDate":"2014-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71027047","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. Yamaguchi, H. Motoyoshi, T. Tanikawa, T. Aoki, M. Niwano, Y. Takeuchi, Y. Endo
The specific surface area (SSA) of snow can be used as an objective measurement to define the optical sphere diameter of snow; it is therefore a helpful parameter to describe the physical properties of snow, such as albedo. Recently, measurement of snow SSA in the field has become easier with the use of optical methods based on near-infrared reflectance values (Ref). However, existing optical methods have only been validated for dry snow conditions in the field. In this study, we tested the possibility of applying the optical method using light with wavelength of around 900 nm (NIR photometry) to wet snow zones in Japan by comparing the findings with snow pit observation data. Our results indicated that NIR photometry can be applied to wet snow zones before the main melt season when the liquid water content is small, but problems arose during melt season due to the appearance of darker layers with more high liquid water content. To resolve these problems, we propose three improvements to NIR photometry: using three calibration targets ranging from high Ref to low Ref in coverage; establishing an estimation formula for SSA from measured Ref, including lower Ref values; and considering how water in the snow influences Ref.
{"title":"Application of snow specific surface area measurement using an optical method based on near-infrared reflectance around 900-nm wavelength to wet snow zones in Japan","authors":"S. Yamaguchi, H. Motoyoshi, T. Tanikawa, T. Aoki, M. Niwano, Y. Takeuchi, Y. Endo","doi":"10.5331/BGR.32.55","DOIUrl":"https://doi.org/10.5331/BGR.32.55","url":null,"abstract":"The specific surface area (SSA) of snow can be used as an objective measurement to define the optical sphere diameter of snow; it is therefore a helpful parameter to describe the physical properties of snow, such as albedo. Recently, measurement of snow SSA in the field has become easier with the use of optical methods based on near-infrared reflectance values (Ref). However, existing optical methods have only been validated for dry snow conditions in the field. In this study, we tested the possibility of applying the optical method using light with wavelength of around 900 nm (NIR photometry) to wet snow zones in Japan by comparing the findings with snow pit observation data. Our results indicated that NIR photometry can be applied to wet snow zones before the main melt season when the liquid water content is small, but problems arose during melt season due to the appearance of darker layers with more high liquid water content. To resolve these problems, we propose three improvements to NIR photometry: using three calibration targets ranging from high Ref to low Ref in coverage; establishing an estimation formula for SSA from measured Ref, including lower Ref values; and considering how water in the snow influences Ref.","PeriodicalId":9345,"journal":{"name":"Bulletin of glaciological research","volume":"32 1","pages":"55-64"},"PeriodicalIF":1.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71027373","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}
Glaciological observations were conducted in 2012 and 2013 at the SIGMA‑A site on the northwest Greenland ice sheet (78°03�06�N 67°37�42�W 1490 m a.s.l. as part of the Snow Impurity and Glacial Microbe effects on abrupt warming in the Arctic (SIGMA project. The meteorological conditions during the two observations were quite different. The meteorological condition during the 2012 observation period was warm and heavy rainfall occurred during the observation period thus the snow was very wet. In contrast the meteorological condition during the observation period in 2013 was cold with a blowing snow event thus the snow was quite dry. The glaciological observations in 2012 consisted of 1 snow‑stake measurements 2 snow pit observations 3 grain size observations for validation of satellite‑derived snow products 4 snow specific surface area measurements using a near‑infrared camera 5 snow sampling for chemical analyses and 6 drilling of firn cores with a hand auger. The glaciological observations in 2013 consisted of 1 snow‑stake measurements 2 snow pit observations and 3 snow sampling for chemical analyses.
{"title":"Glaciological observations in 2012 and 2013 at SIGMA-A site, Northwest Greenland（北西グリーンランド , SIGMA-Aサイトにおける 2012年, 2013年の雪氷調査）","authors":"Satoru Yamaguchi, S. Matoba, Tetsuhide Yamazaki, Akane Tsushima, Masashi Niwano, Tomonori Tanikawa, Teruo Aoki","doi":"10.5331/BGR.32.95","DOIUrl":"https://doi.org/10.5331/BGR.32.95","url":null,"abstract":"Glaciological observations were conducted in 2012 and 2013 at the SIGMA‑A site on the northwest Greenland ice sheet (78°03�06�N 67°37�42�W 1490 m a.s.l. as part of the Snow Impurity and Glacial Microbe effects on abrupt warming in the Arctic (SIGMA project. The meteorological conditions during the two observations were quite different. The meteorological condition during the 2012 observation period was warm and heavy rainfall occurred during the observation period thus the snow was very wet. In contrast the meteorological condition during the observation period in 2013 was cold with a blowing snow event thus the snow was quite dry. The glaciological observations in 2012 consisted of 1 snow‑stake measurements 2 snow pit observations 3 grain size observations for validation of satellite‑derived snow products 4 snow specific surface area measurements using a near‑infrared camera 5 snow sampling for chemical analyses and 6 drilling of firn cores with a hand auger. The glaciological observations in 2013 consisted of 1 snow‑stake measurements 2 snow pit observations and 3 snow sampling for chemical analyses.","PeriodicalId":9345,"journal":{"name":"Bulletin of glaciological research","volume":"32 1","pages":"95-105"},"PeriodicalIF":1.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71027337","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. Hori, T. Aoki, T. Tanikawa, K. Kuchiki, M. Niwano, S. Yamaguchi, S. Matoba
The potential of the thermal infrared (TIR) remote sensing for discriminating surface snow types was examined by analyzing TIR radiances acquired from space over the Greenland ice sheet. The brightness temperature difference (BTD) between TIR wavelengths of 11 and 12μm was found to increase in accordance with in situ observed evolutions of surface snow type. Spatial and temporal distributions of BTD over the entire ice sheet indicated that BTD has a sensitivity of about 1.2 K for variations of the possible snow types. The observed behaviors of BTD were coincident with those predicted by a radiative transfer calculation using previous in situ measured snow emissivities, although some biases on the order of 0.1–0.3 K remain. The dependence of BTD on the surface snow type was also consistent with the behaviors of snow reflectance at the shortwave infrared (SWIR) wavelength 1.6μm, which is a measure of snow grain size, except for the case of melting wet snow. The inconsistency in the wet snow case was considered to be due to the different optical responses of the TIR and SWIR signals to wet snow, which suggested the possibility of using TIR signals to discriminate wet/dry conditions of snow cover in an old stage. As a result, it is determined that TIR remote sensing has potential not only as an approach supplementary to the SWIR method for assessing surface snow types in daytime but also as the only method for simultaneous retrieval of snow type and surface temperature in nighttime.
{"title":"Dependence of thermal infrared emissive behaviors of snow cover on the surface snow type","authors":"M. Hori, T. Aoki, T. Tanikawa, K. Kuchiki, M. Niwano, S. Yamaguchi, S. Matoba","doi":"10.5331/BGR.32.33","DOIUrl":"https://doi.org/10.5331/BGR.32.33","url":null,"abstract":"The potential of the thermal infrared (TIR) remote sensing for discriminating surface snow types was examined by analyzing TIR radiances acquired from space over the Greenland ice sheet. The brightness temperature difference (BTD) between TIR wavelengths of 11 and 12μm was found to increase in accordance with in situ observed evolutions of surface snow type. Spatial and temporal distributions of BTD over the entire ice sheet indicated that BTD has a sensitivity of about 1.2 K for variations of the possible snow types. The observed behaviors of BTD were coincident with those predicted by a radiative transfer calculation using previous in situ measured snow emissivities, although some biases on the order of 0.1–0.3 K remain. The dependence of BTD on the surface snow type was also consistent with the behaviors of snow reflectance at the shortwave infrared (SWIR) wavelength 1.6μm, which is a measure of snow grain size, except for the case of melting wet snow. The inconsistency in the wet snow case was considered to be due to the different optical responses of the TIR and SWIR signals to wet snow, which suggested the possibility of using TIR signals to discriminate wet/dry conditions of snow cover in an old stage. As a result, it is determined that TIR remote sensing has potential not only as an approach supplementary to the SWIR method for assessing surface snow types in daytime but also as the only method for simultaneous retrieval of snow type and surface temperature in nighttime.","PeriodicalId":9345,"journal":{"name":"Bulletin of glaciological research","volume":"35 2 1","pages":"33-45"},"PeriodicalIF":1.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71027198","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}
Naoko Nagatsuka, N. Takeuchi, J. Uetake, R. Shimada
The mineralogical composition of cryoconite on a glacial surface was investigated on six glaciers in northwest Greenland (Qaanaaq Qaqortaq Tugto Bowdoin Sun and Scarlet Heart. The X‑ray diffraction analysis showed that the cryoconites mainly contained seven silicate minerals: hornblende quartz potassium feldspar plagioclase illite kaolinite and chlorite. Semi‑quantitative mineralogical analysis of the silicate mineral composition on the Qaanaaq Glacier showed little variation among the samples collected from five different elevations. This indicates that the minerals on the glacier were probably dominated by dust from a unique source which is recently transported from local sediments including soil and moraine. On the other hand the mineral composition varied significantly among the glaciers. Based on the clay mineral content the glaciers could be classified into three groups. Type A: high clay mineral content composed of illite and kaolinite found on Qaanaaq Qaqortaq and Tugto; Type B: high clay mineral content composed of only kaolinite found on Sun; and Type C: lower clay mineral content composed of only kaolinite found on Bowdoin and Scarlet Heart. The geographical distribution of the types of glaciers did not correspond with the geology in this area indicating that the mineralogical composition is not determined just by the geologi‑ cal conditions around glaciers but also by other factors such as the redistribution of sediments by glacial fluvial or coastal processes.
{"title":"Mineralogical composition of cryoconite on glaciers in northwest Greenland","authors":"Naoko Nagatsuka, N. Takeuchi, J. Uetake, R. Shimada","doi":"10.5331/BGR.32.107","DOIUrl":"https://doi.org/10.5331/BGR.32.107","url":null,"abstract":"The mineralogical composition of cryoconite on a glacial surface was investigated on six glaciers in northwest Greenland (Qaanaaq Qaqortaq Tugto Bowdoin Sun and Scarlet Heart. The X‑ray diffraction analysis showed that the cryoconites mainly contained seven silicate minerals: hornblende quartz potassium feldspar plagioclase illite kaolinite and chlorite. Semi‑quantitative mineralogical analysis of the silicate mineral composition on the Qaanaaq Glacier showed little variation among the samples collected from five different elevations. This indicates that the minerals on the glacier were probably dominated by dust from a unique source which is recently transported from local sediments including soil and moraine. On the other hand the mineral composition varied significantly among the glaciers. Based on the clay mineral content the glaciers could be classified into three groups. Type A: high clay mineral content composed of illite and kaolinite found on Qaanaaq Qaqortaq and Tugto; Type B: high clay mineral content composed of only kaolinite found on Sun; and Type C: lower clay mineral content composed of only kaolinite found on Bowdoin and Scarlet Heart. The geographical distribution of the types of glaciers did not correspond with the geology in this area indicating that the mineralogical composition is not determined just by the geologi‑ cal conditions around glaciers but also by other factors such as the redistribution of sediments by glacial fluvial or coastal processes.","PeriodicalId":9345,"journal":{"name":"Bulletin of glaciological research","volume":"25 1","pages":"107-114"},"PeriodicalIF":1.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5331/BGR.32.107","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71027015","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}
{"title":"Light-absorbing snow impurity concentrations measured on Northwest Greenland ice sheet in 2011 and 2012","authors":"T. Aoki, S. Matoba, S. Yamaguchi, T. Tanikawa, M. Niwano, K. Kuchiki, K. Adachi, J. Uetake, H. Motoyama, M. Hori","doi":"10.5331/BGR.32.21","DOIUrl":"https://doi.org/10.5331/BGR.32.21","url":null,"abstract":"Light-absorbingsnowimpuritiesofelementalcarbon�(EC),�organiccarbon�(OC),�andmineraldusthave� beenmeasuredatthreelocationsatelevationsfrom�1,469�to�1,992�monAugust�1,�2011,�andatthesite� SIGMA-A�(78�N,�68�W,�elevation�1,490�m)�onthenorthwestGreenlandicesheet�(GrIS)�duringtheperiod� fromJune�28�toJuly�12,�2012. AtSIGMA-A,�aremarkablesnowsurfaceloweringtogetherwithsnow� meltingwasobservedduringtheobservationperiodin�2012,�whenarecordsurfacemeltingeventoccurred� overtheGrIS.� Theconcentrationsinthesurfacewere� 0.9,� 3.8,� and� 107�ppbwforEC,� OC,� anddust,� respectively,�atthebeginningoftheperiod,�whichincreasedto�4.9,�17.2,�and�1327�ppbwforEC,�OC,�anddust,� respectively,�attheend. TheECanddustconcentrationswereremarkablyhigherthanthoseatthethree� locationsin�2011�andtherecentmeasurementsatSummit. However,�ourmeasurementsforECandOC� couldbeunderestimatedbecausearecentstudyindicatesthatthecollectionefficiencyofaquartzfiber�","PeriodicalId":9345,"journal":{"name":"Bulletin of glaciological research","volume":"32 1","pages":"21-31"},"PeriodicalIF":1.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5331/BGR.32.21","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71027066","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. Takeuchi, Naoko Nagatsuka, J. Uetake, R. Shimada
Spatial variations in impurities (cryoconite) on the glacier surface were investigated on Qaanaaq Ice Cap and Tugto Glacier in the northwest Greenland in the melting season of 2012. Abundance of impurities ranged from 0.36 to 119 g m -2 (dry weight, mean: 18.8 g m -2 ) on bare ice and from 0.01 to 8.7 g m -2
研究了2012年融化季格陵兰西北部Qaanaaq冰帽和Tugto冰川表面杂质(冰晶)的空间变化规律。在裸冰上，杂质丰度从0.36到119 g m -2(干重，平均值:18.8 g m -2)，从0.01到8.7 g m -2
{"title":"Spatial variations in impurities (cryoconite) on glaciers in northwest Greenland","authors":"N. Takeuchi, Naoko Nagatsuka, J. Uetake, R. Shimada","doi":"10.5331/BGR.32.85","DOIUrl":"https://doi.org/10.5331/BGR.32.85","url":null,"abstract":"Spatial variations in impurities (cryoconite) on the glacier surface were investigated on Qaanaaq Ice Cap and Tugto Glacier in the northwest Greenland in the melting season of 2012. Abundance of impurities ranged from 0.36 to 119 g m -2 (dry weight, mean: 18.8 g m -2 ) on bare ice and from 0.01 to 8.7 g m -2","PeriodicalId":9345,"journal":{"name":"Bulletin of glaciological research","volume":"32 1","pages":"85-94"},"PeriodicalIF":1.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5331/BGR.32.85","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71027141","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. Niwano, T. Aoki, K. Kuchiki, M. Hosaka, Y. Kodama, S. Yamaguchi, H. Motoyoshi, Y. Iwata
The 1D multilayered physical snowpack model Snow Metamorphism and Albedo Process (SMAP), which was originally designed for climate studies, is now updated by incorporating a detailed water movement scheme, realistic snow settlement process and limitation for the Richardson number to ensure minimum turbulent exchanges even under highly stable atmospheric conditions. The evaluation of the updated version of SMAP was first performed using the data obtained at Sapporo, Japan, during the 20072009 winters and the effectiveness of these updates was demonstrated in terms of snow depth and snow surface temperature. However, we pointed out that the choice of maximum Richardson number should be further examined. To test the reliability of SMAP under different climate conditions, we applied it to Naga oka, Japan, during the 2011-2012 winter. At Nagaoka, we performed snow-soil-coupled simulations, because ground heat flux was not available during the study period. For this purpose, we developed a soil submodel for SMAP. Consequently, we confirmed that the updated version performed better than the old version in terms of mass balance simulations at Nagaoka too. Although mass balance-related parameters of the snowpack simulated by the updated version agreed well with observations during the accumulation period, the model substantially overestimated snow depth, as well as column-integrated snow water equivalent during the ablation period. By discussing the reasons for these discrepancies, we highlighted that further investigation on snow-melt processes for thick seasonal snowpack is necessary.
{"title":"Evaluation of updated physical snowpack model SMAP","authors":"M. Niwano, T. Aoki, K. Kuchiki, M. Hosaka, Y. Kodama, S. Yamaguchi, H. Motoyoshi, Y. Iwata","doi":"10.5331/BGR.32.65","DOIUrl":"https://doi.org/10.5331/BGR.32.65","url":null,"abstract":"The 1D multilayered physical snowpack model Snow Metamorphism and Albedo Process (SMAP), which was originally designed for climate studies, is now updated by incorporating a detailed water movement scheme, realistic snow settlement process and limitation for the Richardson number to ensure minimum turbulent exchanges even under highly stable atmospheric conditions. The evaluation of the updated version of SMAP was first performed using the data obtained at Sapporo, Japan, during the 20072009 winters and the effectiveness of these updates was demonstrated in terms of snow depth and snow surface temperature. However, we pointed out that the choice of maximum Richardson number should be further examined. To test the reliability of SMAP under different climate conditions, we applied it to Naga oka, Japan, during the 2011-2012 winter. At Nagaoka, we performed snow-soil-coupled simulations, because ground heat flux was not available during the study period. For this purpose, we developed a soil submodel for SMAP. Consequently, we confirmed that the updated version performed better than the old version in terms of mass balance simulations at Nagaoka too. Although mass balance-related parameters of the snowpack simulated by the updated version agreed well with observations during the accumulation period, the model substantially overestimated snow depth, as well as column-integrated snow water equivalent during the ablation period. By discussing the reasons for these discrepancies, we highlighted that further investigation on snow-melt processes for thick seasonal snowpack is necessary.","PeriodicalId":9345,"journal":{"name":"Bulletin of glaciological research","volume":"32 1","pages":"65-78"},"PeriodicalIF":1.0,"publicationDate":"2014-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71027421","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}
F. Nakazawa, T. Segawa, S. Kohshima, Lobzang（ロブザン） Gyenden, T. Fujiki, Karma（カルマ） Toeb
Pollen analyses were carried out on samples from a snow pit and an ice core in the saddle of the Gangjoe La Glacier in the Bhutan Himalayas in 2002. The main purpose of this study was to implement an ice core analysis to investigate the recent snow depositional environment at the upstream part, particularly to understand melting status. The total sample length was 6.60 m. Three pollen concentration peaks were observed at the ice core depths of 0.46-0.56, 1.44-1.54, and 2.52-2.56 m. These peaks contained pollen, from various taxa, that had scattered in the study region between March and October. On the other hand, air temperature data showed that the summer melting season on the glacier was from June to September. Therefore, we assumed that snow deposited from approximately March to September over the past three years was lost due to summer melting. The ice layers between the pollen concentration peaks seemed to correspond to snow accumulation from September to March of the following year. These results provided a clue to better understand melting and snow depositional conditions at the study site.
{"title":"Recent melting status at the upstream part of the Gangjoe La Glacier, Bhutan Himalayas, determined by pollen analysis of an ice core","authors":"F. Nakazawa, T. Segawa, S. Kohshima, Lobzang（ロブザン） Gyenden, T. Fujiki, Karma（カルマ） Toeb","doi":"10.5331/BGR.31.1","DOIUrl":"https://doi.org/10.5331/BGR.31.1","url":null,"abstract":"Pollen analyses were carried out on samples from a snow pit and an ice core in the saddle of the Gangjoe La Glacier in the Bhutan Himalayas in 2002. The main purpose of this study was to implement an ice core analysis to investigate the recent snow depositional environment at the upstream part, particularly to understand melting status. The total sample length was 6.60 m. Three pollen concentration peaks were observed at the ice core depths of 0.46-0.56, 1.44-1.54, and 2.52-2.56 m. These peaks contained pollen, from various taxa, that had scattered in the study region between March and October. On the other hand, air temperature data showed that the summer melting season on the glacier was from June to September. Therefore, we assumed that snow deposited from approximately March to September over the past three years was lost due to summer melting. The ice layers between the pollen concentration peaks seemed to correspond to snow accumulation from September to March of the following year. These results provided a clue to better understand melting and snow depositional conditions at the study site.","PeriodicalId":9345,"journal":{"name":"Bulletin of glaciological research","volume":"31 1","pages":"1-7"},"PeriodicalIF":1.0,"publicationDate":"2013-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.5331/BGR.31.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71027458","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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