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614 results on '"Motoyama, H."'

3. A regime shift in surface temperature over the East Antarctic Plateau in the twentieth century

Author

Kurita, N., Kameda, T., Motoyama, H., Naohiko, H., Sugiura, K., Lazzara, M., Mikolajczyk, D., Welhouse, L., Keller, L., and Weidner, G.

Abstract

In contrast to the Antarctic coastal region, there are only a few staffed weather stations in the remote plateau region. In particular, inland Dronning Maud Land (DML) on East Antarctic Plateau is one of the regions in which weather observations are the shortest and sparsest in the world. Several automatic weather stations (AWSs) have been installed since 1990s. However, owing to their remoteness and harsh environment, the missing observations occur frequently and these data gaps hinder the analysis of temperature variability and changes in the region. Here, we present complete 40-years long temperature records for Dome Fuji, Relay Station, and Mizuho in the inland DLM region, in which observations have been corrected, and gaps have been filled using the state-of-the-art global atmospheric reanalysis data. The records show the similar interannual variability among each station. A stacked annual temperature reveals a statistically significant warming trend since the late 1990s. The most rapid warming is observed during the austral spring. The springtime warming resulted from an increase of warm northerly winds associated with the enhanced cyclonic anomaly in the Weddell Sea. The circulation changes in the Weddell Sea is closely linked to the tropical-polar teleconnection. The impact of changes in tropical sea surface temperatures seem to extend not only to the Antarctic Peninsula and West Antarctica, but also to the East Antarctic Plateau., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Published
2023
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8. A Review of Antarctic Surface Snow Isotopic Composition : Observations, Atmospheric Circulation, and Isotopic Modeling

Author

Masson-Delmotte, V., Hou, S., Ekaykin, A., Jouzel, J., Aristarain, A., Bernardo, R. T., Bromwich, D., Cattani, O., Delmotte, M., Falourd, S., Frezzotti, M., Gallée, H., Genoni, L., Isaksson, E., Landais, A., Helsen, M. M., Hoffmann, G., Lopez, J., Morgan, V., Motoyama, H., Noone, D., Oerter, H., Petit, J. R., Royer, A., Uemura, R., Schmidt, G. A., Schlosser, E., Simões, J. C., Steig, E. J., Stenni, B., Stievenard, M., van den Broeke, M. R., van de Wal, R. S. W., van de Berg, W. J., Vimeux, F., and White, J. W. C.

Published
2008

10. High‐Resolution 10 Be and 36 Cl Data from the Antarctic Dome Fuji Ice Core (∼100 years around 5480 BCE): An Unusual Grand Solar Minimum Occurrence?

Author

Kanzawa, K., primary, Miyake, F., additional, Horiuchi, K., additional, Sasa, K., additional, Takano, K., additional, Matsumura, M., additional, Takahashi, T., additional, Motizuki, Y., additional, Takahashi, K., additional, Nakai, Y., additional, Ohtani, K., additional, Tada, Y., additional, Ochiai, Y., additional, Motoyama, H., additional, Matsuzaki, H., additional, Yamazaki, A., additional, Muramatsu, Y., additional, and Yamagata, T., additional

Published
2021
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14. High‐Resolution 10Be and 36Cl Data From the Antarctic Dome Fuji Ice Core (∼100 Years Around 5480 BCE): An Unusual Grand Solar Minimum Occurrence?

Author

Kanzawa, K., Miyake, F., Horiuchi, K., Sasa, K., Takano, K., Matsumura, M., Takahashi, T., Motizuki, Y., Takahashi, K., Nakai, Y., Ohtani, K., Tada, Y., Ochiai, Y., Motoyama, H., Matsuzaki, H., Yamazaki, A., Muramatsu, Y., and Yamagata, T.

Subjects
COSMOGENIC nuclides, ANTARCTIC ice, COSMIC rays, ASTROPHYSICAL radiation, IONIZING radiation
Abstract

Cosmogenic nuclides in tree rings and polar ice cores record the information of past cosmic ray intensities and solar activities. A large 14C increase over 10 years has been discovered around 5480 BCE. The 14C variations in this event differ from those of other short‐term cosmic ray events and typical grand solar minima. To elucidate the cause of the 14C increase around 5480 BCE, we measured the 10Be and 36Cl concentrations in the Antarctic Dome Fuji ice core at quasi‐annual and 4–5 years resolutions, respectively. Based on the combined 14C, 10Be, and 36Cl data, the 5480 BCE event was probably not caused by a solar proton event (SPE) or a gamma‐ray event, because the 36Cl concentration did not significantly increase as expected in these events. The incremented 10Be data were enhanced similarly to those of recent grand solar minima, but more rapidly increased (over ∼10 years). These results suggest that an unusual grand solar minimum occurred around 5480 BCE, characterized by a rapidly decreasing solar activity. Key Points: New high‐resolution 10Be and 36Cl data for the 5480 BCE cosmic ray event were taken from the Antarctic Dome Fuji ice coreMeasured 36Cl/10Be ratio was not suitable for either solar proton event or gamma‐ray event originsThe 5480 BCE event might refer to the unusual grand solar minimum which solar activity decreased rapidly in ∼10 years [ABSTRACT FROM AUTHOR]

Published
2021
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18. Electromagnetic field radiation model for lightning strokes to tall structures

Author

Motoyama, H., Janischewskyj, W., Hussein, A.M., Rusan, R., Chisholm, W.A., and Chang, J.-S.

Subjects
Electromagnetic radiation -- Models, Lightning -- Models, Electromagnetic fields -- Measurement, Electromagnetic measurements -- Methods, Business, Computers, Electronics, Electronics and electrical industries
Abstract

This paper describes observation and analysis of electromagnetic field radiation from lightning strokes to tall structures. Electromagnetic field waveforms and current waveforms of lightning strokes to the CN Tower have been simultaneously measured since 1991. A new calculation model of electromagnetic field radiation is proposed. The proposed model consists of the lightning current propagation and distribution model and the electromagnetic field radiation model. Electromagnetic fields calculated by the proposed model, based on the observed lightning current at the CN Tower, agree well with the observed fields at 2km north of the tower. KEYWORD - Lightning, Electromagnetic field radiation, Lightning to tall structures, EMC, Electromagnetic transient

Published
1996

19. Measurement of lightning surges on test transmission line equipped with arresters struck by natural and triggered lightning

Author

Matsumoto, Y., Sakuma, O., Shinjo, J., Saiki, M., Wakai, T., Sakai, T., Nagasaka, H., Motoyama, H., and Ishii, M.

Subjects
Transients (Electricity) -- Measurement, Lightning-arresters -- Research, Power lines -- Research, Electric power transmission -- Research, Business, Computers, Electronics, Electronics and electrical industries
Abstract

Measurement of lightning surges caused by natural or rocket-triggered lightning strokes has been carried out on a 275kV test transmission line since 1987. In November 1993, lightning currents at the tower top, the ground wires, the tower legs and the transmission line arresters, along with the voltages across the insulator strings were measured simultaneously four times. One of the four flashes was natural lightning, and its peak value was +132kA. In this case, the arresters operated, and the insulator voltages where the arresters were equipped were controlled properly. The result of a multi-phase analysis by EMTP agreed well with the measured waveforms.

Published
1996

22. State dependence of climatic instability over the past 720,000 years from Antarctic ice cores and climate modeling

Author

Kawamura, K., Abe-Ouchi, A., Motoyama, H., Ageta, Y., Aoki, S., Azuma, N., Fujii, Y., Fujita, K., Fujita, S., Fukui, K., Furukawa, T., Furusaki, A., Goto-Azuma, K., Greve, R., Hirabayashi, M., Hondoh, T., Hori, A., Horikawa, S., Horiuchi, K., Igarashi, M., Iizuka, Y., Kameda, T., Kanda, H., Kohno, M., Kuramoto, A., Nagashima, Y., Nakayama, Y., Nakazawa, T., Nakazawa, F., Nishio, F., Obinata, I., Ohgaito, R., Oka, A., Okuno, J., Okuyama, J., Oyabu, I., Parrenin, F., Pattyn, F., Saito, F., Saito, T., Sakurai, T., Sasa, K., Seddik, H., Shibata, Y., Shinbori, K., Suzuki, K., Suzuki, T., Takahashi, A., Takahashi, S., Takata, M., Tanaka, Y., Uemura, R., Watanabe, G., Watanabe, O., Yamasaki, T., Yokoyama, K., Yoshimori, M., and Yoshimoto, T.

Abstract

Climatic variabilities on millennial and longer time scales with a bipolar seesaw pattern have been documented in paleoclimatic records, but their frequencies, relationships with mean climatic state, and mechanisms remain unclear. Understanding the processes and sensitivities that underlie these changes will underpin better understanding of the climate system and projections of its future change. We investigate the long-term characteristics of climatic variability using a new ice-core record from Dome Fuji, East Antarctica, combined with an existing long record from the Dome C ice core. Antarctic warming events over the past 720,000 years are most frequent when the Antarctic temperature is slightly below average on orbital time scales, equivalent to an intermediate climate during glacial periods, whereas interglacial and fully glaciated climates are unfavourable for a millennial-scale bipolar seesaw. Numerical experiments using a fully coupled atmosphere-ocean general circulation model with freshwater hosing in the northern North Atlantic showed that climate becomes most unstable in intermediate glacial conditions associated with large changes in sea ice and the Atlantic Meridional Overturning Circulation. Model sensitivity experiments suggest that the prerequisite for the most frequent climate instability with bipolar seesaw pattern during the late Pleistocene era is associated with reduced atmospheric CO2 concentration via global cooling and sea ice formation in the North Atlantic, in addition to extended Northern Hemisphere ice sheets.

Published
2017

26. Living-donor Lobar Lung Transplantation Outcomes in Pediatric Patients

Author

Ueda, S., primary, Chen-Yoshikawa, T.F., additional, Kayawake, H., additional, Tokuno, J., additional, Yamagishi, H., additional, Gochi, F., additional, Okabe, R., additional, Saito, M., additional, Takahagi, A., additional, Nakajima, D., additional, Motoyama, H., additional, Hamaji, M., additional, Aoyama, A., additional, and Date, H., additional

Published
2018
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28. Protective Effect of a Hydrogen-Rich Preservation Solution During Cold Ischemia in Rat Lung Transplantation

Author

Saito, M., primary, Chen-Yoshikawa, T., additional, Hirano, S., additional, Kayawake, H., additional, Ueda, S., additional, Tokuno, J., additional, Yamagishi, H., additional, Gochi, F., additional, Okabe, R., additional, Takahagi, A., additional, Motoyama, H., additional, Hamaji, M., additional, Aoyama, A., additional, and Date, H., additional

Published
2018
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29. Characteristics of De Novo Donor-specific Anti-HLA Antibodies (DSAs) in Living-donor Lobar and Cadaveric Lung Transplantation

Author

Gochi, F., primary, Chen-Yoshikawa, T., additional, Tokuno, J., additional, Ueda, S., additional, Kayawake, H., additional, Yamagishi, H., additional, Okabe, R., additional, Takahagi, A., additional, Saito, M., additional, Nakajima, D., additional, Motoyama, H., additional, Hamaji, M., additional, Aoyama, A., additional, and Date, H., additional

Published
2018
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31. The presence of multiple NS 5A RAS s is associated with the outcome of sofosbuvir and ledipasvir therapy in NS 5A inhibitor‐naïve patients with chronic HCV genotype 1b infection in a real‐world cohort

Author

Kozuka, R., primary, Hai, H., additional, Motoyama, H., additional, Hagihara, A., additional, Fujii, H., additional, Uchida‐Kobayashi, S., additional, Morikawa, H., additional, Enomoto, M., additional, Murakami, Y., additional, Kawada, N., additional, and Tamori, A., additional

Published
2018
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40. Tapering, Not Discontinuation, of Epoprostenol Prevents PGD Requiring ECMO Support in Recipients with Severe Pulmonary Hypertension

Author

Aoyama, A., primary, Kinoshita, H., additional, Yoneda, T., additional, Goda, Y., additional, Oda, H., additional, Kayawake, H., additional, Ueda, S., additional, Minakata, K., additional, Motoyama, H., additional, Hamaji, M., additional, Hijiya, K., additional, Chen-Yoshikawa, T.F., additional, and Date, H., additional

Published
2017
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42. Airway-Centered Inflammation Induced by Lipopolysaccharide (LPS) Leads to BOS-Like Phenotype of CLAD in Rat Lung Transplantation

Author

Takahagi, A., primary, Sato, M., additional, Chen-Yoshikawa, T., additional, Yoshizawa, A., additional, Ohata, K., additional, Saito, M., additional, Okabe, R., additional, Gochi, F., additional, Yamagishi, H., additional, Hamaji, M., additional, Motoyama, H., additional, Hijiya, K., additional, Aoyama, A., additional, and Date, H., additional

Published
2017
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44. Differences in De Novo Donor-Specific Anti-HLA Antibodies Between Living-Donor Lobar and Cadaveric Lung Transplantation

Author

Gochi, F., primary, Chen-Yoshikawa, T.F., additional, Kondo, T., additional, Ohsumi, A., additional, Ohata, K., additional, Takahagi, A., additional, Saito, M., additional, Okabe, R., additional, Yamagishi, H., additional, Hamaji, M., additional, Hijiya, K., additional, Motoyama, H., additional, Aoyama, A., additional, and Date, H., additional

Published
2017
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47. 10Be Signature of the Cosmic Ray Event in the 10th Century CE in Both Hemispheres, as Confirmed by Quasi‐Annual 10Be Data From the Antarctic Dome Fuji Ice Core.

Author

Miyake, F., Horiuchi, K., Motizuki, Y., Nakai, Y., Takahashi, K., Masuda, K., Motoyama, H., and Matsuzaki, H.

Subjects
COSMIC rays, NUCLIDES, ICE sheets, BERYLLIUM, SODIUM ions
Abstract

Cosmogenic nuclides are good indicators of past cosmic ray events and variations. To verify such phenomena, it is important to evaluate them using multiple nuclides from different archives. The cosmic ray event in 993–994 Common Era (CE) has already been confirmed with 14C and 10Be data, which show rapid increases in the concentrations. However, the 10Be data were obtained from the Greenland ice cores in the Northern Hemisphere. To investigate the extent of the 10Be increase in the Southern Hemisphere, we measured quasi‐annual 10Be concentrations between 980 and 1,011 CE in the Antarctic Dome Fuji ice core. We observed a ~50% increase in 10Be concentration around 994 CE, consistent with the Greenland data. Increases in 10Be concentrations in both hemispheres support a solar origin of the 994‐CE event. In addition, we propose a method of evaluating the so‐called "system effect" for 10Be deposition by extracting common components from 10Be and Na+ data. Plain Language Summary: New quasi‐annual beryllium‐10 measurements were made with the Dome Fuji ice core from Antarctica over the period in which the 994 cosmic ray event would be expected. We observed an approximately 50% increase in beryllium‐10 concentrations, which is consistent with the beryllium‐10 increases observed in the Greenland ice cores. This lends support to a solar origin of the 994 event. We propose a phenomenological method for evaluating a common deposition component between quasi‐annual beryllium‐10 and sodium ion data. Key Points: New quasi‐annual 10Be data were taken with Antarctic Dome Fuji ice core over the period when the 994‐CE cosmic ray event took placeWe observed a ~50% increase in 10Be concentrations, which is consistent with the 10Be increases observed in the Greenland ice coresWe propose a phenomenological method for evaluating a common deposition component between quasi‐annual beryllium‐10 data and Na+ data [ABSTRACT FROM AUTHOR]

Published
2019
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48. 南極内陸における大気・雪面相互作用の理解に向けて

Author

Fujita, K, Iizuka, Y, Hara, K, Matoba, S, Hirasawa, N, and Motoyama, H

Abstract

Although the East Antarctica has been believed to be stable against the global warming, influences of the warming, sensitive response of ice-streams or melt-refreeze footprint at high elevation were recently reported. Ice-core studies have provided perspective not only on the past, but also on future climate change. Many uncertainties still remain in the climate proxies because some processes are unknown how water stable isotopes and aerosol particles were deposited, varied and preserved in the ice.Aerosol particles in snow and ice are useful proxies of past-atmospheric environment. We have recently revealed that sulfate salts flux is correlated with the stable isotope ratio during recent glacial-interglacial cycle. Water stable isotopes are the most fundamental proxies of past-temperature. We have recently revealed that the water stable isotopes in inland Antarctica should have been altered from the original precipitated ones by large variability of accumulation rates in the very arid environment.Through the phase IX of the Japanese Antarctic Research Project (2016-2022), we propose an integrated observation to understand the interactions between atmosphere and snow surface in inland Antarctica. In particular we focus on the alternation processes of water stable isotopes and aerosol particles after their deposition. We will conduct samplings of aerosols and shallow snow pits through the traverse in inland Antarctica in several summer seasons. In addition, we prepare for the near-future overwintering at the new Dome Fuji Station because the processes during winter are totally equivocal. Our study will bridge a gap between the atmospheric transports and the ice-core paleoclimate., 第4回極域科学シンポジウム特別セッション：[S] 南極研究の将来展望―第Ⅸ期6か年計画策定に向けて11月14日（木） 国立極地研究所 ２階大会議室

Published
2013

49. 酸素・水素安定同位体比を用いた南極ドームふじ氷床コアにおける過去72万年の気温復元

Author

Masson-Delmotte, V., Jouzel, J., Uemura, R., Motoyama, H., Miyake, T., Hirabayashi, M., Kuramoto, T., Ohno, Hiroshi, Kohno, M., Goto-Azuma, K., Fujii, Y., Fujita, K., Horikawa, S., Igarashi, M., Iizuka, Y., Suzuki, K., and Suzuki, T.

Abstract

第4回極域科学シンポジウム横断セッション：[IC] 極域アイスコア・地形地質・モデリングから迫る古環境変動とそのメカニズム11月13日（水） 国立極地研究所 ３階 ラウンジ

Published
2013

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