Updated on 2022/05/21

写真a

 
NAGAI, Hiroto
 
Affiliation
Faculty of Education and Integrated Arts and Sciences, School of Education
Job title
Assistant Professor(without tenure)
Homepage URL
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持続可能な開発目標(SDGs: Sustainable Development Goals)の達成に資するため、地球観測衛星のデータを利用した地球科学研究を推進します。

研究の主軸は(1)データサイエンスとしての衛星地球観測学の追究、(2)先端衛星システムの校正検証に対応するための次世代型自動気象観測システムの開発、(3)非専門家のための環境/災害リモートセンシングに関する包括的な教育プログラムの開発です。

現在の具体的な研究課題は主に(A)氷河・氷河湖の変動解析、(B)日本国内の湿雪に対応した積雪深空間分布推定、(C)堅牢性の高い災害状況把握に関する手法開発及び実証評価です。

Education

  • 2010.04
    -
    2014.03

    Nagoya University   Graduate School of Environmental Studies   Doctor degree program, Department of Earth and Environmental Sciences  

  • 2008.04
    -
    2010.03

    Nagoya University   Graduate School of Environmental Studies   Master's degree program, Department of Earth and Environmental Sciences  

  • 2004.04
    -
    2008.03

    Nagoya University   School of Science   Department of Earth and Planetary Sciences  

Degree

  • Nagoya Univ.   Doctor of Environmental study

Research Experience

  • 2022.04
    -
    Now

    Tokyo City University   Faculty of Environmental and Information Studies

  • 2021.08
    -
    Now

    Japan Agency for Marine-Earth Science and Technology   招聘研究員

  • 2018.07
    -
    Now

    NIED   Guest Researcher

  • 2018.04
    -
    Now

    Waseda University   Department of Education   Lecturer

  • 2020.04
    -
    2022.03

    日本大学   文理学部   非常勤講師

  • 2019.04
    -
    2019.09

    新潟大学   非常勤講師

  • 2014.04
    -
    2018.03

    Japan Aerospace Exploration Agency   Earth Observation Research Center

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Professional Memberships

  •  
     
     

    THE JAPANESE SOCIETY OF SNOW AND ICE

  •  
     
     

    THE REMOTE SENSING SOCIETY OF JAPAN

 

Research Areas

  • Disaster prevention engineering   Hazard response with satellite data and GIS

  • Atmospheric and hydrospheric sciences   Geographic condition of Himalayan glaciers/glacial lakes

  • Environmental dynamic analysis   Remote sensing of environment

  • Science education   Earth observation data for education

Research Interests

  • 衛星地球観測学

  • 合成開口レーダー

  • Google Earth Engine

  • NoBADI

  • SINOBi

  • 臨床環境学

  • SDGs

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Papers

  • SAR-Based Flood Monitoring for Flatland with Frequently Fluctuating Water Surfaces: Proposal for the Normalized Backscatter Amplitude Difference Index (NoBADI)

    Hiroto Nagai, Takahiro Abe, Masato Ohki

    Remote Sensing   13 ( 20 ) 4136 - 4136  2021.10  [Refereed]

    Authorship:Lead author, Corresponding author

     View Summary

    Space-based synthetic aperture radar (SAR) is a powerful tool for monitoring flood conditions over large areas without the influence of clouds and daylight. Permanent water surfaces can be excluded by comparing SAR images with pre-flood images, but fluctuating water surfaces, such as those found in flat wetlands, introduce uncertainty into flood mapping results. In order to reduce this uncertainty, a simple method called Normalized Backscatter Amplitude Difference Index (NoBADI) is proposed in this study. The NoBADI is calculated from a post-flood SAR image of backscatter amplitude and multiple images on non-flooding conditions. Preliminary analysis conducted in the US state of Florida, which was affected by Hurricane Irma in September 2017, shows that surfaces frequently covered by water (more than 20% of available data) have been successfully excluded by means of C-/L-band SAR (HH, HV, VV, and VH polarizations). Although a simple comparison of pre-flood and post-flood images is greatly affected by the spatial distribution of the water surface in the pre-flood image, the NoBADI method reduces the uncertainty of the reference water surface. This advantage will contribute in making quicker decisions during crisis management.

    DOI

  • Synthetic Aperture Radar Flood Detection under Multiple Modes and Multiple Orbit Conditions: A Case Study in Japan on Typhoon Hagibis, 2019

    Ryo Natsuaki, Hiroto Nagai

    Remote Sensing   12 ( 6 ) 903 - 903  2020.03  [Refereed]  [International journal]

     View Summary

    Flood detection using a spaceborne synthetic aperture radar (SAR) has become a powerful tool for organizing disaster responses. The detection accuracy is increased by accumulating pre-event observations, whereas applying multiple observation modes results in an inadequate number of observations with the same mode from the same orbit. Recent flood detection studies take advantage of the large number of pre-event observations taken from an identical orbit and observation mode. On the other hand, those studies do not take account of the use of multiple orbits and modes. In this study, we examined how the analysis results suffered when pre-event observations were only taken from a different orbit or mode to that of the post-event observation. Experimental results showed that inundation areas were overlooked under such non-ideal conditions. On the other hand, the detection accuracy could be recovered by combining analysis results from possible alternate datasets and became compatible with ideal cases.

    DOI

  • Sensitivity and Limitation in Damage Detection for Individual Buildings Using InSAR Coherence—A Case Study in 2016 Kumamoto Earthquakes

    Natsuaki, R, Nagai, H, Tomii, N, Tadono, T

    Remote Sensing   10 ( 2 ) 245 - 245  2018.02  [Refereed]

    DOI

  • ALOS-2 Mission Status Updates.

    Masato Ohki, Takeshi Motooka, Takahiro Abe, Hiroto Nagai, Takeo Tadono, Yukihiro Kankaku, Masanobu Shimada

    2018 IEEE International Geoscience and Remote Sensing Symposium, IGARSS 2018, Valencia, Spain, July 22-27, 2018     4166 - 4168  2018  [Refereed]

    DOI

  • Performance of ALOS-2 PALSAR-2 for disaster response

    Ryo Natsuaki, Masato Ohki, Hiroto Nagai, Takeshi Motohka, Takeo Tadono, Masanobu Shimada, Shinichi Suzuki

    International Geoscience and Remote Sensing Symposium (IGARSS)   2017-   2434 - 2437  2017.12  [Refereed]

     View Summary

    In 2016, the Advanced Land Observing Satellite-2 (ALOS-2, 'DAICHI-2') observed various disaster affected areas. Japan Aerospace Exploration Agency (JAXA) operated the emergency observation more than hundred times in the year. The Phased Array type L-band Synthetic Aperture Radar-2 (PALSAR-2) aboard ALOS-2 contributed for detecting the disaster affected area, ground deformation and flood affected area. Especially for the ground deformation and damaged area detection caused by the devastating earthquakes in 2016, e.g., Kumamoto earthquakes in Japan and Kaikoura earthquake in New Zealand, researchers provided variable analytical results from ALOS-2 observation data. In this paper, some examples of the emergency observation results are presented.

    DOI

  • Multiple remote-sensing assessment of the catastrophic collapse in Langtang Valley induced by the 2015 Gorkha earthquake

    Hiroto Nagai, Manabu Watanabe, Naoya Tomii, Takeo Tadono, Shinichi Suzuki

    NATURAL HAZARDS AND EARTH SYSTEM SCIENCES   17 ( 11 ) 1907 - 1921  2017.11  [Refereed]

    Authorship:Lead author, Corresponding author

     View Summary

    The main shock of the 2015 Gorkha Earthquake in Nepal induced numerous avalanches, rockfalls, and landslides in Himalayan mountain regions. A major village in the Langtang Valley was destroyed and numerous people were victims of a catastrophic avalanche event, which consisted of snow, ice, rock, and blast wind. Understanding the hazard process mainly depends on limited witness accounts, interviews, and an in situ survey after a monsoon season. To record the immediate situation and to understand the deposition process, we performed an assessment by means of satellite-based observations carried out no later than 2 weeks after the event. The avalanche-induced sediment deposition was delineated with the calculation of decreasing coherence and visual interpretation of amplitude images acquired from the Phased Array-type L-band Synthetic Aperture Radar-2 (PALSAR-2). These outline areas are highly consistent with that delineated from a high-resolution optical image of WorldView-3 (WV-3). The delineated sediment areas were estimated as 0.63 km(2) (PALSAR-2 coherence calculation), 0.73 km(2) (PALSAR-2 visual interpretation), and 0.88 km(2) (WV-3). In the WV-3 image, surface features were classified into 10 groups. Our analysis suggests that the avalanche event contained a sequence of (1) a fast splashing body with an air blast, (2) a huge, flowing muddy mass, (3) less mass flowing from another source, (4) a smaller amount of splashing and flowing mass, and (5) splashing mass without flowing on the east and west sides. By means of satellite-derived pre-and post-event digital surface models, differences in the surface altitudes of the collapse events estimated the total volume of the sediments as 5.51 +/- 0.09 +/- 10(6) m(3), the largest mass of which are distributed along the river floor and a tributary water stream. These findings contribute to detailed numerical simulation of the avalanche sequences and source identification; furthermore, altitude measurements after ice and snow melting would reveal a contained volume of melting ice and snow.

    DOI

  • Topographic controls on the debris-cover extent of glaciers in the Eastern Himalayas: Regional analysis using a novel high-resolution glacier inventory

    Sunal Ojha, Koji Fujita, Akiko Sakai, Hiroto Nagai, Damodar Lamsal

    QUATERNARY INTERNATIONAL   455 ( 7 ) 82 - 92  2017.10  [Refereed]

     View Summary

    To better understand the influence of topography on the formation of Himalayan debris-covered glaciers, we manually digitized 5301 glaciers, covering an area of 5691 +/- 893 km(2), from high-resolution Advanced Land Observing Satellite imagery, and identified 842 debris-covered glaciers with a debris-covered area of 3839 +/- 753 km(2). This estimation of the debris-covered area of these glaciers is a novel approach in the Eastern Himalayas. We investigated the relationship between the debris-covered area and the corresponding potential debris supply (PDS) slopes for the debris-covered glaciers across the region. The PDS slopes on the southern side show better correlation with their debris-covered area formation than those situated on the northern side of the Himalayan barrier, with this correlation weakening toward the western massifs. Further investigation showed that PDS slopes oriented SE to Wexert a stronger control on the formation of debris-covered areas, which is related to the diurnal freezeethaw cycle on the southern slope of the mountain barrier. (C) 2017 Elsevier Ltd and INQUA. All rights reserved.

    DOI

  • Evaluating the Scale and Potential of GLOF in the Bhutan Himalayas Using a Satellite-Based Integral Glacier-Glacial Lake Inventory

    Hiroto Nagai, Jinro Ukita, Chiyuki Narama, Koji Fujita, Akiko Sakai, Takeo Tadono, Tsutomu Yamanokuchi, Nobuhiro Tomiyama

    GEOSCIENCES   7 ( 3 ) 77  2017.09  [Refereed]

    Authorship:Lead author, Corresponding author

     View Summary

    A comprehensive glacier-glacial lake inventory was developed for the Bhutan Himalayas based on satellite observations between 1987-1990 and 2006-2011. In total, 733 lakes (covering 82.6 km(2)) were delineated between 4000 and 6000 m a.s.l. and their relationships to associated glaciers were documented. Using this new inventory, the scale and potential for glacial lake outburst flooding (GLOF) based on multiple criteria was examined. This included a history of connectivity characteristics of glacial lakes to mother glaciers, potential flood volumes, and debris-cover of mother glaciers in addition to the conventional criteria of expansion rate and lake size. The majority of the lakes with high expansion rates (more than double in size) and large areas (> 0.1 km(2)) met the conditions of being continuously in contact with a mother debris-covered glacier for nearly 20 years. Based on these multiple criteria, two lakes were identified as having potential for large-scale GLOF. Potentially dangerous glacial lakes listed in the International Centre for Integrated Mountain Development (ICIMOD) study were re-visited, and some overlaps with the glacier-glacial lake inventory were found.

    DOI

  • Development and application of space-borne DEM generation

    Hiroto Nagai, Takeo Tadono

    Seppyo   79 ( 1 ) 43 - 61  2017.01

    Authorship:Lead author, Corresponding author

    DOI

  • SAR interferometry using ALOS-2 PALSAR-2 data for the Mw 7.8 Gorkha, Nepal earthquake

    Ryo Natsuaki, Hiroto Nagai, Takeshi Motohka, Masato Ohki, Manabu Watanabe, Rajesh B. Thapa, Takeo Tadono, Masanobu Shimada, Shinichi Suzuki

    Earth Planet Sp   68 ( 1 )  2016.02  [Refereed]

    DOI

  • 4. だいち2号および国際災害チャータ・センチネルアジアによる平成28年熊本地震の対応

    高橋 陪夫, 田殿 武雄, 大木 真人, 夏秋 嶺, 永井 裕人, 石原 光則, 本岡 毅, 鈴木 新一, 石野 達哉, 櫻井 洋祐, 宮崎 景太, 千葉 丈久, 高田 裕司, 山本 英子, 根本 沙織, 内藤 一郎

    写真測量とリモートセンシング   55 ( 3 ) 154 - 155  2016

    DOI CiNii

  • Generation of the 30 M-MESH global digital surface model by alos prism

    T. Tadono, H. Nagai, H. Ishida, F. Oda, S. Naito, K. Minakawa, H. Iwamoto

    International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives   41   157 - 162  2016  [Refereed]

     View Summary

    Topographical information is fundamental to many geo-spatial related information and applications on Earth. Remote sensing satellites have the advantage in such fields because they are capable of global observation and repeatedly. Several satellite-based digital elevation datasets were provided to examine global terrains with medium resolutions e.g. the Shuttle Radar Topography Mission (SRTM), the global digital elevation model by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER GDEM). A new global digital surface model (DSM) dataset using the archived data of the Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) onboard the Advanced Land Observing Satellite (ALOS, nicknamed "Daichi") has been completed on March 2016 by Japan Aerospace Exploration Agency (JAXA) collaborating with NTT DATA Corp. and Remote Sensing Technology Center, Japan. This project is called "ALOS World 3D" (AW3D), and its dataset consists of the global DSM dataset with 0.15 arcsec. pixel spacing (approx. 5 m mesh) and ortho-rectified PRISM image with 2.5 m resolution. JAXA is also processing the global DSM with 1 arcsec. spacing (approx. 30 m mesh) based on the AW3D DSM dataset, and partially releasing it free of charge, which calls "ALOS World 3D 30 m mesh" (AW3D30). The global AW3D30 dataset will be released on May 2016. This paper describes the processing status, a preliminary validation result of the AW3D30 DSM dataset, and its public release status. As a summary of the preliminary validation of AW3D30 DSM, 4.40 m (RMSE) of the height accuracy of the dataset was confirmed using 5,121 independent check points distributed in the world.

    DOI

  • Emergency observation and its analysis using ALOS-2 PALSAR-2 in 2015

    Ryo Natsuaki, Hiroto Nagai, Takeshi Motohka, Masato Ohki, Manabu Watanabe, Shinichi Suzuki

    LAND SURFACE AND CRYOSPHERE REMOTE SENSING III   9877  2016  [Refereed]

     View Summary

    Advanced Land Observing Satellite-2 (ALOS-2, "DAICHI-2") performed various emergency observation with its Phased Array type L-band Synthetic Aperture Radar-2 (PALSAR-2) in Asia in 2015. Especially for corresponding to the emergency request from Sentinel Asia related to the Mw 7.8 Gorkha Nepal Earthquake 2015, PALSAR-2 successfully detected not only the crustal deformation but also the avalanches and local displacements. In this presentation, we describe these performances, analysis and the other emergency observations.

    DOI

  • EMERGENCY OBSERVATION AND DISASTER MONITORING PERFORMED BY ALOS-2 PALSAR-2

    Ryo Natsuaki, Takeshi Motohka, Manabu Watanabe, Masato Ohki, Rajesh B. Thapa, Hiroto Nagai, Takeo Tadono, Masanobu Shimada, Shinichi Suzuki

    2016 IEEE INTERNATIONAL GEOSCIENCE AND REMOTE SENSING SYMPOSIUM (IGARSS)     3849 - 3852  2016

     View Summary

    One of the main missions of the Advanced Land Observing Satellite-2 (ALOS-2, "DAICHI-2") is the disaster monitoring. Japan Aerospace Exploration Agency (JAXA) has operated the emergency observation more than hundred times in 2015. Not only the most important event in 2015, the Mw 7.8 Gorkha earthquake on April 25, the Phased Array type L-band Synthetic Aperture Radar-2 (PALSAR-2) aboard ALOS-2 observed various floods, volcano eruptions and earthquakes. In this paper, we present some emergency observation results which were impossible to be performed by the previous ALOS. That is, automatically burst aligned ScanSAR to ScanSAR interferometry and, left / right looking for increasing acquisition opportunity.

    DOI

  • ALOS-2 PALSAR-2データによる平成27年8月関東・東北豪雨の洪水域把握と精度検証

    大木真人, 渡邉 学, 夏秋 嶺, 本岡 毅, 永井裕人, 田殿武雄, 鈴木新一, 石井景子, 伊藤拓弥, 山之口勤, 島田政信

    日本リモートセンシング学会誌   36 ( 4 ) 348 - 358  2016  [Refereed]

     View Summary

    <p>Rapid and all-weather detection of flood areas is needed to monitor and mitigate flood disasters. This study addressed flood area detection using ALOS-2 PALSAR-2 data acquired during the 2015 heavy rainfall disaster in the Kanto and Tohoku area of Japan. We propose an approach to flood area detection by thresholding amplitude and interferometric coherence images for non-urban and urban areas, respectively. PALSAR-2-derived flood areas were validated using the inundation map provided by the Geospatial Information Authority of Japan (GSI) and showed 75% accuracy and a 0.51 kappa coefficient in flood/non-flood discrimination. The effectiveness of a lower incidence angle (less than 40 degrees) and a high-sensitivity observation mode (6-m resolution mode) for detecting non-urban flooding was also demonstrated by a comparative study. Interferometric phase variation was revealed to be more effective in detecting urban flooding than conventional interferometric coherence. Our results demonstrate the feasibility of PALSAR-2 for rapid flood monitoring and can be used as a reference for possible future flood disasters.</p>

    DOI CiNii

  • Glacier area shrinkage in eastern Nepal Himalaya since 1992 using high-resolution inventories from aerial photographs and ALOS satellite images

    Sunal Ojha, Koji Fujita, Katsuhiko Asahi, Akiko Sakai, Damodar Lamsal, Takayuki Nuimura, Hiroto Nagai

    JOURNAL OF GLACIOLOGY   62 ( 233 ) 512 - 524  2016  [Refereed]

     View Summary

    To better understand the recent wide-scale changes in glacier coverage, we created and compared two glacier inventories covering eastern Nepal, based on aerial photographs (1992) and high-resolution Advanced Land Observing Satellite (ALOS) imagery (2006-10). The ALOS-derived inventory contained 1034 debris-free and 256 debris-covered glaciers with total and average areas of 440.2 +/- 33.3 and 0.42 km(2) and 1074.4 +/- 206.4 and 4.19 km(2), respectively. We found that the debris-free glaciers have lost 11.2% (0.7 +/- 0.1% a(-1)) of their area since 1992, whereas the number of glaciers increased by 5% because of fragmentation. The area change was significantly correlated by simple linear regression with minimum elevation (r = 0.30), maximum elevation (r = -0.18), altitudinal range (r = -0.50), glacier area (r = -0.62) and mean slope (r = 0.16), confirming that larger glaciers tended to lose a larger area (but a smaller percentage) than smaller glaciers. The infra-regional analysis of the glacier changes clearly showed higher shrinkage rates in the western massifs compared with the eastern massifs. In addition, 61 small glaciers covering an area of 2.4 km(2) have completely disappeared since 1992.

    DOI

  • Comparison of multiple glacier inventories with a new inventory derived from high-resolution ALOS imagery in the Bhutan Himalaya

    H. Nagai, K. Fujita, A. Sakai, T. Nuimura, T. Tadono

    CRYOSPHERE   10 ( 1 ) 65 - 85  2016  [Refereed]

    Authorship:Lead author, Corresponding author

     View Summary

    Digital glacier inventories are invaluable data sets for revealing the characteristics of glacier distribution and for upscaling measurements from selected locations to entire mountain ranges. Here, we present a new inventory of Advanced Land Observing Satellite (ALOS) imagery and compare it with existing inventories for the Bhutan Himalaya. The new inventory contains 1583 glaciers (1487 +/- 235 km(2)), thereof 219 debris-covered glaciers (951 +/- 193 km(2)) and 1364 debris-free glaciers (536 +/- 42 km(2)). Moreover, we propose an index for quantifying consistency between two glacier outlines. Comparison of the overlap ratio demonstrates that the ALOS-derived glacier inventory contains delineation uncertainties of 10-20% which depend on glacier size, that the shapes and geographical locations of glacier outlines derived from the fourth version of the Randolph Glacier Inventory have been improved in the fifth version, and that the latter is consistent with other inventories. In terms of whole glacier distribution, each data set is dominated by glaciers of 1.0-5.0 km(2) area (31-34% of the total area), situated at approximately 5400m elevation (nearly 10% in 100m bin) with either north or south aspects (22 and 15 %). However, individual glacier outlines and their area exhibit clear differences among inventories. Furthermore, consistent separation of glaciers with inconspicuous termini remains difficult, which, in some cases, results in different values for glacier number. High-resolution imagery from Google Earth can be used to improve the interpretation of glacier outlines, particularly for debris-covered areas and steep adjacent slopes.

    DOI

  • Status of 'ALOS World 3D (AW3D)' global DSM generation

    Takeo Tadono, Junichi Takaku, Ken Tsutsui, Fumiko Oda, Hiroto Nagai

    International Geoscience and Remote Sensing Symposium (IGARSS)   2015-   3822 - 3825  2015.11  [Refereed]

     View Summary

    The Japan Aerospace Exploration Agency is generating the global digital elevation/surface model (DEM/DSM) and ortho-rectified image (ORI) using the archived data of the Panchromatic Remote-sensing Instrument for Stereo Mapping (PRISM) onboard the Advanced Land Observing Satellite (ALOS, nicknamed 'Daichi'), which was operated from 2006 to 2011. The overview and the processing status of the global DSM/ORI dataset generation project called 'ALOS World 3D' (AW3D) is introduced in this paper. It is necessary to consider data processing strategies, since the processing capabilities of the level 1 standard product and AW3D products must be developed both hardware and software to achieve the project aims. The processing strategies and an initial validation of generated DSM dataset are described. As an initial validation results, 4.10 m of height accuracy as root mean square error was confirmed. The generation and distribution of a lower resolution AW3D DSM dataset is also introduced.

    DOI

  • The GAMDAM glacier inventory: A quality-controlled inventory of Asian glaciers

    T. Nuimura, A. Sakai, K. Taniguchi, H. Nagai, D. Lamsal, S. Tsutaki, A. Kozawa, Y. Hoshina, S. Takenaka, S. Omiya, K. Tsunematsu, P. Tshering, K. Fujita

    Cryosphere   9 ( 3 ) 849 - 864  2015.05  [Refereed]

     View Summary

    © Author(s) 2015. CC Attribution 3.0 License. We present a new glacier inventory for high-mountain Asia named "Glacier Area Mapping for Discharge from the Asian Mountains" (GAMDAM). Glacier outlines were delineated manually using 356 Landsat ETM+ scenes in 226 path-row sets from the period 1999-2003, in conjunction with a digital elevation model (DEM) and high-resolution Google EarthTM imagery. Geolocations are largely consistent between the Landsat imagery and DEM due to systematic radiometric and geometric corrections made by the United States Geological Survey. We performed repeated delineation tests and peer review of glacier outlines in order to maintain the consistency and quality of the inventory. Our GAMDAM glacier inventory (GGI) includes 87 084 glaciers covering a total area of 91 263 ± 13 689 km2 throughout high-mountain Asia. In the Hindu Kush-Himalaya range, the total glacier area in our inventory is 93% that of the ICIMOD (International Centre for Integrated Mountain Development) inventory. Discrepancies between the two regional data sets are due mainly to the effects of glacier shading. In contrast, our inventory represents significantly less surface area ('24%) than the recent global Randolph Glacier Inventory, version 4.0 (RGI), which includes 119 863 ± 9201 km2 for the entirety of high Asian mountains. Likely causes of this disparity include headwall definition, effects of exclusion of shaded glacier areas, glacier recession since the 1970s, and inclusion of seasonal snow cover in the source data of the RGI, although it is difficult to evaluate such effects quantitatively. Further rigorous peer review of GGI will both improve the quality of glacier inventory in high-mountain Asia and provide new opportunities to study Asian glaciers.

    DOI

  • Climate regime of Asian glaciers revealed by GAMDAM glacier inventory

    A. Sakai, T. Nuimura, K. Fujita, S. Takenaka, H. Nagai, D. Lamsal

    CRYOSPHERE   9 ( 3 ) 865 - 880  2015  [Refereed]

     View Summary

    Among meteorological elements, precipitation has a large spatial variability and less observation, particularly in high-mountain Asia, although precipitation in mountains is an important parameter for hydrological circulation. We estimated precipitation contributing to glacier mass at the median elevation of glaciers, which is presumed to be at equilibrium-line altitude (ELA) such that mass balance is zero at that elevation, by tuning adjustment parameters of precipitation. We also made comparisons between the median elevation of glaciers, including the effect of drifting snow and avalanche, and eliminated those local effects. Then, we could obtain the median elevation of glaciers depending only on climate to estimate glacier surface precipitation. The calculated precipitation contributing to glacier mass can elucidate that glaciers in arid high-mountain Asia receive less precipitation, while much precipitation makes a greater contribution to glacier mass in the Hindu Kush, the Himalayas, and the Hengduan Shan due to not only direct precipitation amount but also avalanche nourishment. We classified glaciers in high-mountain Asia into summer-accumulation type and winter-accumulation type using the summer-accumulation ratio and confirmed that summer-accumulation-type glaciers have a higher sensitivity than winter-accumulation-type glaciers.

    DOI

  • Climatic and topographic influences on glacier distribution in the Bhutan Himalaya

    Hiroto Nagai, Koji Fujita, Akiko Sakai, Takayuki Nuimura, Takeo Tadono

    The Cryosphere Discussion   8   1305 - 1336  2014.02

    Authorship:Lead author, Corresponding author

    DOI

  • Southwest-facing slopes control the formation of debris-covered glaciers in the Bhutan Himalaya

    H. Nagai, K. Fujita, T. Nuimura, A. Sakai

    CRYOSPHERE   7 ( 4 ) 1303 - 1314  2013  [Refereed]

    Authorship:Lead author, Corresponding author

     View Summary

    To understand the formation conditions of debris-covered glaciers, we examined the dimension and shape of debris-covered areas and potential debris-supply (PDS) slopes of 213 glaciers in the Bhutan Himalaya. This was undertaken using satellite images with 2.5m spatial resolution for manual delineation of debris-covered areas and PDS slopes. The most significant correlation exists between surface area of southwest-facing PDS slopes and debris-covered area. This result suggests that the southwest-facing PDS slopes supply the largest quantity of debris mantle. The shape of debris-covered areas is also an important variable, quantitatively defined using a geometric index. Elongate or stripe-like debris-covered areas on north-flowing glaciers are common throughout the Bhutan Himalaya. In contrast, south-flowing glaciers have large ablation zones, entirely covered by debris. Our findings suggest that this difference is caused by effective diurnal freeze-thaw cycles rather than seasonal freeze-thaw cycles, permafrost degradation, or snow avalanches. In terms of geographic setting, local topography also contributes to glacier debris supply and the proportion of debris cover on the studied glaciers is suppressed by the arid Tibetan climate, whereas the north-to-south asymmetric topography of the Bhutan Himalaya has less influence on the proportion of debris cover.

    DOI

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Books and Other Publications

  • 2016 Kumamoto Earthquake: Measuring Uplift and Depression Using Synthetic Aperture Radar

    Hiroto Nagai, Ryo Natsuaki, Mitsunori Ishihara, Takeo Tadono, Takeshi Motohka, Shinichi Suzuki( Part: Contributor, Poster donation)

    Esri  2017.07

     View Summary

    http://www.esri.com/esri-map-book/#/details/15/2

  • 臨床環境学

    渡邊誠一郎, 中塚 武, 王 智弘( Part: Contributor, 4.4、コラム2)

    名古屋大学出版会  2014 ISBN: 9784815807825

     View Summary

    環境の病いとどう向き合うべきか。環境問題発生のダイナミズムを見据え、従来の学問分野を超えた新しいアプローチが、現場で診断から治療までを一貫して行う臨床環境学であり、それを支える基礎環境学である。個別性に配慮したこれら先進的な試みを、理論と実践の両面から初めて解説。
    http://www.unp.or.jp/ISBN/ISBN978-4-8158-0781-8.html

Misc

  • Backscatter amplitude analysis of SAR satellites at snow-buried corner reflectors

    永井裕人, 永井裕人, 河島克久, 山下克也, 砂子宗次朗, 山口悟, 架谷隆太, 関矢祐輝, 中山舜介, 大川翔太郎, 上原崇雅

    雪氷研究大会講演要旨集(Web)   2020  2020

    J-GLOBAL

  • Estimation of snow depth spatial distribution using space-borne synthetic aperture radars- Basic analysis evaluation and synchronous satellite observation planning -

    永井裕人, 永井裕人, 山口悟, 山下克也, 本吉弘岐, 林諒, 架谷隆太, 大川翔太郎, 八木拓馬, 河島克久, 佐藤匠, 佐藤匠, 上石勲, 鹿島真弓

    雪氷研究大会講演要旨集(Web)   2019  2019

    J-GLOBAL

  • PALSAR-2後方散乱強度変化と積雪深との関係

    永井裕人, 山口悟, 山下克也, 鹿島真弓

    日本地球惑星科学連合大会予稿集(Web)   2019  2019

    J-GLOBAL

  • 2016年熊本地震における中程度被災家屋の空間分布解析

    永井裕人, 夏秋嶺

    日本地球惑星科学連合大会予稿集(Web)   2017  2017

    J-GLOBAL

  • 地球観測衛星による熊本地震の緊急観測対応

    永井裕人, 夏秋嶺, 石原光則, 大木真人, 田殿武雄, 本岡毅, 鈴木新一

    日本地球惑星科学連合大会予稿集(Web)   2016  2016

    J-GLOBAL

  • 2015年ネパール地震におけるALOS-2/ALOSによる干渉解析と被害抽出

    夏秋嶺, 永井裕人, 本岡毅, 大木真人, 渡邉学, 田殿武雄, THAPA Rajesh bahadur, 島田政信, 鈴木新一

    日本地球惑星科学連合大会予稿集(Web)   2015  2015

    J-GLOBAL

  • Challenges and salient features of the cooperation between students from different academic backgrounds, participating in Basic and Clinical Environmental Studies through ORT (On-site Research Training)

    Kazu HAGIHARA, Hiroto NAGAI, Yoshihiro CHIBA, Keisuke TOMITA, Mitsuyuki TOMIYAMA, Hirokazu KATO, Hiroyuki SHIMIZU, Noriyuki KAWAMURA, Yasuhiro HIRANO, Takashi TASHIRO, Hiromi YAMASHITA

    Journal of Human and Environmental Symbiosis   24   71 - 78  2014.01  [Refereed]

    Rapid communication, short report, research note, etc. (scientific journal)  

  • 学生の見た臨床環境学のカベとツボ

    永井裕人

    名古屋大学グローバルCOEプログラム「地球学から基礎・臨床環境学への展開」2012年度臨床環境学研修(伊勢湾流域圏ORT)櫛田川ORT報告書    2013.03

    Other  

  • 茶畑での"松阪牛液肥"利用で変わる櫛田川流域の環境

    青山ちひろ, 永井裕人, シャリフィ・アユーブ

    名古屋大学グローバルCOEプログラム「地球学から基礎・臨床環境学への展開」2011年度臨床環境学研修(伊勢湾流域圏ORT)櫛田川ORT報告書     30 - 48  2012.03

    Other  

  • 阿久比町における竹林の拡大に耕作放棄地の発生が与える影響

    永井裕人, 内田貴之, 岡田知也, 足立典子

    名古屋大学グローバルCOEプログラム「地球学から基礎・臨床環境学への展開」2010年度臨床環境学研修(伊勢湾流域圏ORT) 阿久比川ORT報告書     21 - 29  2011.03

    Other  

  • ヒマラヤ滞在記(後編)

    岡本 祥子, 石田 依子, 永井 裕人, 保科 優, 山本 知聖, BODINGTON Dylan

    雪氷 : 日本雪氷協會雜誌   71 ( 6 ) 503 - 508  2009.11

    CiNii

  • ヒマラヤ滞在記(前編)

    岡本 祥子, 石田 依子, 永井 裕人, 保科 優, 山本 知聖, BODINGTON Dylan

    雪氷 : 日本雪氷協會雜誌   71 ( 5 ) 403 - 409  2009.09

    CiNii

▼display all

Other

  • Peer-reviewed journals

     View Summary

    MDPI: Remote Sensing (2019; 2020)
    MDPI: Water (2018; 2021)
    International Journal of Remote Sensing (2017)
    Geomorphology (2016)
    Geografiska Annaler: Series A, Physical Geography (2015)
    Annals of Glaciology (2015; 2017)
    Polar Science (2021; 2022)
    Geocarto International (2022)

Awards

  • 優秀論文発表賞

    2019.06   (一社)日本リモートセンシング学会   正規化後方散乱強度変化指標(NoBADI)の提案と米国ハリケーン被害への応用

    Winner: Hiroto NAGAI, Masato Ohki, Takahiro Abe

  • 第12回GISコミュニティフォーラム・マップギャラリー第5位

    2016.05   ESRIジャパンユーザ会   衛星データで見る2016年熊本地震

    Winner: Hiroto NAGAI

  • 第11回GISコミュニティフォーラム・マップギャラリー第2位

    2015.05   ESRIジャパンユーザ会   JAXA地球観測衛星によるネパール地震の緊急観測対応 ~地殻変動量の検出から山岳集落の状況把握まで~

    Winner: 永井裕人, 夏秋嶺, 本岡毅, 大木真人, 渡邉学, 田殿武雄, Rajesh Bahadur Thapa, 島田政信, 鈴木新一

     View Summary

    http://www.esrij.com/news/details/74590/

  • 平成25年度 中谷宇吉郎科学奨励賞

    2014.02   Kaga city  

    Winner: Hiroto NAGAI

  • 地球人間圏科学セクション学生優秀発表賞

    2013.05   日本地球惑星科学連合   ALOS衛星を用いたブータンヒマラヤにおける氷河台帳の作成

    Winner: 永井裕人

     View Summary

    http://www.jpgu.org/prize/

Research Projects

  • SAR データ等を用いた豪雪地域の積雪深分布プロダクトの開発

    Japan Aerospace Exploration Agency  2nd Research Announcement on the Earth Observations

    Project Year :

    2019.04
    -
    2022.03
     

    Hiroto NAGAI

  • PALSAR-2データを用いた山間地域における水害・土砂災害のコヒーレンス解析

    Japan Aerospace Exploration Agency  ALOS/RA-6

    Project Year :

    2016.04
    -
    2021.03
     

    Hiroto NAGAI

  • 衛星を活用した積雪域の広域積雪審分布把握を目指した積雪中マイクロ波反射特性の解明

    新潟大学 災害・復興科学研究所  平成31年度 新潟大学災害・復興科学研究所共同研究

    Project Year :

    2019.05
    -
    2020.03
     

    Hiroto NAGAI

  • 衛星リモートセンシングによる氷河湖の短期面積変動の解明

    JSPS  KAKENHI (early-career)

    Project Year :

    2018.04
    -
    2020.03
     

    Hiroto NAGAI

  • 衛星を利用した積雪深分布把握に基づく道路除排雪システムの検討

    内閣府  先進的な宇宙利用モデル実証プロジェクト

    Project Year :

    2018
    -
    2019.03
     

    山口悟

Presentations

  • A case study of earthquake-induced landslide mapping using Normalized Backscatter Amplitude Difference Index for a space-borne Synthetic Aperture Radar

    Takamasa Uehara, Hiroto Nagai

    AGU2021 

    Presentation date: 2021.12

    Event date:
    2021.12
     
     

     View Summary

    [IN45C-0474]

  • Comparison of different atmospheric correction for ASTER data for identifications of pegmatites: a case study in Southern Namibia

    Shunsuke Nakayama, Hiroto Nagai

    AGU2021 

    Presentation date: 2021.12

    Event date:
    2021.12
     
     

     View Summary

    [NS35C-0383]

  • Characteristics of SAR backscatter amplitudes corresponding to the seasonal snow-depth variation at snow-buried cubic corner reflectors installed in Nagaoka, Japan

    Hiroto Nagai, Satoru Yamaguchi, Sojiro Sunako, Katsuya Yamashita, Katsuhisa Kawashima, Ryuta Hasatani, Shunsuke Nakayama, Yuuki Sekiya

    AGU2021 

    Presentation date: 2021.12

    Event date:
    2021.12
     
     

     View Summary

    [C15F-0854]

  • ポスト臨床環境学:分断された言葉の壁を乗り越え、計画された偶発性を使いこなす博士人材キャリアパスについて

    永井裕人  [Invited]

    JpGU2021 

    Presentation date: 2021.06

    Event date:
    2021.05
    -
    2021.06

     View Summary

    [U09-04]

  • 新潟県長岡市における埋雪SAR電波反射鏡の設置観測結果速報(2020/2021冬季)

    永井裕人, 砂子宗次朗, 山下克也, 山口悟

    JpGU2021 

    Presentation date: 2021.06

    Event date:
    2021.05
    -
    2021.06

     View Summary

    [A-CC25]

  • A study on the combined method to grasp volcanic hot spots using Terra/ASTER and Himawari-8/AHI data

    Ryo Hayashi, Hiroto Nagai, Minoru Urai, Hirokazu Yamamoto

    AGU2020 

    Presentation date: 2020.12

     View Summary

    V030-02

  • SAR-based detection of buried ruins: present possibility and uncertainties

    Kurodo Saito, Hiroto Nagai

    AGU2020 

    Presentation date: 2020.12

     View Summary

    NS013-000

  • Observation of cumulonimbus cloud growing process using Himawari-8

    Takuma Yagi, Hiroto Nagai

    AGU2020 

    Presentation date: 2020.12

     View Summary

    NH033-0005

  • Characteristics of rainfall-induced slope-failure distribution focused on geographical, vegetational and geological features: a preliminary case study for Japanese recent extreme events

    Ryoko Nagumo, Hiroto Nagai

    AGU2020 

    Presentation date: 2020.12

     View Summary

    NH001-0001

  • Flood detection with a Support Vector Machine based applied on PALSAR-2 data: Case studies in recent Japanese flood hazards

    Ryuta Hasatani, Hiroto Nagai

    AGU2020 

    Presentation date: 2020.12

     View Summary

    G004-0021

  • Flow analysis of Icelandic glaciers using synthetic aperture radar focused on climate seasonality and ELA setting

    Takuya Mitsuhashi, Hiroto Nagai

    AGU2020 

    Presentation date: 2020.12

     View Summary

    C038-0017

  • Sensitivity analysis of backscatter amplitude at snow-buried corner reflectors using C-/L-band SARs

    Hiroto Nagai, Katsuhisa Kawashima, Katsuya Yamashita, Satoru Yamaguchi, Sojiro Sunako, Ryuta Hasatani, Yuuki Sekiya, Shunsuke Nakayama, Shotaro Ohkawa, Takamasa Uehara

    AGU2020 

    Presentation date: 2020.12

     View Summary

    C005-0006

  • Ice flow velocity and elevation change measurement Shirase Glacier and Totten Glacier using remote sensing data

    Shotaro Ohkawa, Koichiro Doi, Kazuki Nakamura, Hiroto Nagai

    AGU2020 

    Presentation date: 2020.12

     View Summary

    C042-07

  • 雪に埋めた電波反射鏡を用いたSAR衛星マイクロ波反射特性の基本的解析

    永井裕人, 河島克久, 山下克也, 砂子宗次朗, 山口悟, 架谷隆太, 関矢祐輝, 中山舜介, 大川翔太郎, 上原崇雅

    雪氷研究大会2020 

    Presentation date: 2020.11

     View Summary

    A3-21

  • Flow velocity and ice sheet elevation of Shirase Glacier and Totten Glacier from SAR and Laser altimetry

    大川 翔太郎, 土井 浩一郎, 中村 和樹, 永井 裕人

    JpGU2020 

    Presentation date: 2020.07

     View Summary

    M-IS15

  • PALSAR-2衛星を用いた平成30年西日本豪雨における浸水域抽出手法の評価

    架谷 隆太, 永井裕人

    Presentation date: 2020.07

     View Summary

    STT50-P08

  • Details of short-term areal changes on glacial lakes in the Bhutan Himalaya: climatic analysis and SAR-based monitoring

    Hiroto NAGAI

    AGU2019 

    Presentation date: 2019.12

  • Establishing a glacial lake monitoring system with synthetic aperture radar

    Hiroto NAGAI

    Presentation date: 2019.11

  • 合成開口レーダーを用いた積雪深空間分布の推定 -初期解析評価と衛星同期観測計画-

    雪氷研究大会2019 

    Presentation date: 2019.09

  • Detection of flood area using L-band synthetic aperture radar data applied on a case of hurricane Irma, 2017

    Hiroto Nagai, Masato Ohki, Takahiro Abe  [Invited]

    IGARSS2019 

    Presentation date: 2019.07

     View Summary

    TU2.R3.1

  • Algorithm development for snow-depth estimation using PALSAR-2

    Hiroto Nagai, Satoru Yamaguchi, Katsuya Yamashita, Mayumi Kashima

    (社)日本リモートセンシング学会 第66回(令和元年度春季)学術講演会 

    Presentation date: 2019.06

  • PALSAR-2後方散乱強度変化と積雪深との関係

    Hiroto Nagai, Satoru Yamaguchi, Katsuya Yamashita, Mayumi Kashima

    JpGU2019 

    Presentation date: 2019.05

  • Climatic conditions amplifying seasonal areal change of glacial lakes in the Bhutan Himalaya

    Hiroto NAGAI

    AGU2018 

    Presentation date: 2018.12

  • Feasibility assessment of SAR-derived snow-depth map for Japanese wet snow conditions

    Hiroto Nagai, Tomohiro Watanabe, Takeo Tadono, Takeshi Motohka

    AGU2018 

    Presentation date: 2018.12

  • 「だいち2号」を用いた積雪深マップの作成にむけて

    永井 裕人, 渡邉 知弘, 田殿 武雄, 本岡 毅

    日本地球惑星科学連合2018年大会 

    Presentation date: 2018.05

  • 「だいち2号」を用いたブータン氷河湖台帳の更新にむけて

    永井 裕人, 田殿 武雄

    日本地球惑星科学連合2018年大会 

    Presentation date: 2018.05

  • 「だいち2号」を用いたハリケーン・イルマの洪水被害把握

    永井 裕人, 大木 真人, 阿部 隆博

    日本地球惑星科学連合2018年大会 

    Presentation date: 2018.05

  • 正規化後方散乱強度変化指標(NoBADI)の提案と米国ハリケーン被害への応用

    永井裕人, 大木真人, 阿部隆博

    (社)日本リモートセンシング学会 第64回(平成30年度春季)学術講演会 

    Presentation date: 2018.05

  • Short-term expansion of glacial lakes in the Himalayas

    Hiroto Nagai, Takeo Tadono

    AGU2017 

    Presentation date: 2017.12

  • Validation of global-and-free DEM datasets

    Hiroto Nagai, Takeo Tadono

    International Symposium of Remote Sensing 

    Presentation date: 2017.05

  • Which DEM is the best for glaciology? -Evaluation of global-scale DEM products-

    Hiroto Nagai, Takeo Tadono

    EGU2017 General Assembly 

    Presentation date: 2017.04

  • Glacial lake inventory of Bhutan using ALOS data: Completion and application for the risk assessment of glacial lake outburst flood

    Nagai H, Ukita J, Tadono T, Suzuki S, Narama C, Yamanokuchi T, Tomiyama N, Sakai A, Fujita K

    International Symposium on The Cryosphere in a Changing Climate  (Wellington, New Zealand.)  International Glaciological Society

    Presentation date: 2017.02

  • Area change analysis of small glacier lakes in short periods using ALOS-2 and Landsat-8

    Hiroto Nagai, Takeo Tadono, Shinichi Suzuki

    日本リモートセンシング学会第61回(秋季)学術講演会  (新潟)  日本リモートセンシング学会

    Presentation date: 2016.11

     View Summary

    A-4

  • Satellite observation of a glacier lake outburst flood in western Bhutan

    Hiroto Nagai, Takeo Tadono, Shinichi Suzuki

    Japan Geoscience Union 2016  Japan Geoscience Union

    Presentation date: 2016.05

     View Summary

    HSC16-04

  • Preliminary remote sensing assessment of the catastrophic avalanche in Langtang Valley induced by the 2015 Gorkha earthquake, Nepal

    Hiroto Nagai, Manabu Watanabe, Naoya Tomii

    European Geosciences Union General Assembly 2016  (Vienna, Austria)  European Geosciences Union

    Presentation date: 2016.04

     View Summary

    EGU2016-3737

  • 西ブータンで発生した氷河湖決壊洪水に関するALOS-2緊急観測と初期解析結果

    永井裕人, 田殿武雄

    雪氷研究大会 

    Presentation date: 2015.09

  • A 20-year history of glacial lakes in the Bhutan Himalaya (analysed from the ALOS-based integrated glacier-glacial lake inventory)

    Hiroto NAGAI, Jinro UKITA, Takeo TADONO, Chiyuki NARAMA, Tsutomu YAMANOKUCHI, Nobuhiro TOMIYAMA, Akiko SAKAI, Koji FUJITA

    Joint Conference of 30th ISTS, 34th IEPC, & 6th NSAT 

    Presentation date: 2015.07

  • 氷河台帳間におけるデジタイズされた輪郭の比較および評価

    永井裕人, 藤田耕史, 坂井亜規子, 縫村崇行, 田殿武雄

    日本リモートセンシング学会 

    Presentation date: 2015.06

     View Summary

    A7

  • Introduction of ALOS World 3D -Global dataset of high-resolution topography and colored images-

    Hiroto NAGAI, Takeo Tadono

    5th Digital Earth Summit 

    Presentation date: 2014.11

  • ブータンヒマラヤにおける氷河台帳の比較

    永井裕人, 藤田耕史, 坂井亜規子, 縫村崇行, 田殿武雄

    雪氷研究大会 

    Presentation date: 2014.09

  • ブータンヒマラヤにおける氷河分布に対する気候と地形の影響

    永井裕人, 藤田耕史, 縫村崇行, 坂井亜規子, 田殿武雄

    日本リモートセンシング学会 

    Presentation date: 2014.05

  • ブータン・ヒマラヤにおける 氷河周辺斜面の氷河分布への寄与

    Hiroto Nagai, Koji Fujita, Akiko Sakai, Takayuki Nuimura

    雪氷研究大会 

    Presentation date: 2013.09

  • An ALOS-derived glacier inventory of the Bhutan Himalaya

    Hiroto Nagai, Koji Fujita, Takayuki Nuimura, Akiko Sakai

    Japan Geoscience Union Meeting  (Makuhari, Japan) 

    Presentation date: 2013.05

     View Summary

    HTT09-01

  • Analyzing geographic setting of debris-covered glacier in the Bhutan Himalaya

    Nagai H, Fujita K, Nuimura T, Sakai A

    International Symposium on Remote Sensing  (Makuhari, Japan) 

    Presentation date: 2013.05

     View Summary

    A1-01

  • An ALOS-derived glacier inventory of the Bhutan Himalaya

    Nagai H, Fujita K, Nuimura T, Sakai A

    European Geosciences Union General Assembly 2013  (Vienna, Austria) 

    Presentation date: 2013.04

     View Summary

    EGU2013-7798

  • ブータン・ヒマラヤにおける氷河インベントリの作成

    永井裕人, 藤田耕史, 縫村崇行, 坂井亜規子

    雪氷研究大会  (Fukuyama, Japan) 

    Presentation date: 2012.09

     View Summary

    100240

  • ブータン・ヒマラヤにおけるデブリ氷河の形成要因に関する研究

    永井裕人, 藤田耕史

    日本リモートセンシング学会  (Tokyo, Japan) 

    Presentation date: 2012.05

     View Summary

    B22

  • 衛星データを用いたブータン・ヒマラヤにおけるデブリ氷河の形成要因に関する研究

    永井裕人, 藤田耕史, 縫村崇行

    雪氷研究大会  (Nagaoka, Japan) 

    Presentation date: 2011.09

     View Summary

    100117

  • 衛星データを用いたブータン・ヒマラヤにおけるデブリ氷河の形成要因に関する研究

    永井裕人, 縫村崇行, 藤田耕史

    日本地球惑星科学連合大会  (Makuhari, Japan) 

    Presentation date: 2011.05

     View Summary

    HDS025-04

  • 衛星データを用いたブータン・ヒマラヤにおけるデブリ氷河の形成要因に関する研究

    永井裕人, 藤田耕史, 縫村崇行

    日本雪氷学会全国大会  (Sendai, Japan) 

    Presentation date: 2010.09

     View Summary

    100115

  • Formation condition of debris-covered glaciers in the Bhutan Himalaya derived by satellite data

    Nagai H, Fujita K, Nuimura T

    International Symposium on Snow, Ice and Humanity in a Changing Climate  (Sapporo, Japan) 

    Presentation date: 2010.06

     View Summary

    58A111

  • 衛星データを用いたブータン・ヒマラヤにおけるデブリ氷河の形成要因に関する研究.

    永井裕人, 藤田耕史, 縫村崇行

    日本地球惑星科学連合大会  (Makuhari, Japan) 

    Presentation date: 2010.05

     View Summary

    HDS022-06

  • ASTERデータを用いたブータン・ヒマラヤにおけるデブリ氷河の形成要因解析

    永井裕人, 藤田耕史, 縫村崇行

    日本リモートセンシング学会  (Nagoya, Japan) 

    Presentation date: 2009.11

     View Summary

    B05

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Specific Research

  • ブータンヒマラヤにおける地すべり地形の地理空間情報解析

    2021  

     View Summary

    地滑りはアジア山岳域で頻発する自然災害であり、潜在的な発生分布を把握する必要がある。本研究では衛星画像から作成された地形データ「AW3D: Advanced World 3D」について、地滑りリスク評価への適応可能性を評価した。研究対象地域はブータン・ブラマプトラ川流域の3支流の一部、標高1200-3700 mの範囲とした。解析の結果、河川からの距離によらず斜度が約25-30°の範囲の流域、河川から離れるにつれて斜度が40°から30°へ減少する流域、31°から33°への緩やかな増加傾向が見られる流域が認められた。これらは隣接する流域であっても潜在的な地滑りリスクが異なることを示唆する。

  • 合成開口レーダを利用した低湿地における洪水被害抽出方法の検討

    2018  

     View Summary

    合成開口レーダ衛星は洪水被害把握で重要な情報収集手段となりうるが、低湿地帯では基準の水域分布が季節によって様々なため、被害域の推定結果が確定しないという問題がある。本研究では複数の災害前画像から平均的な水域分布を導出し、それに対してどの程度異なったレーダー反射を示すかを定量的に示す指標を考案し、その有効性を検証した。光学衛星画像の被災域を用いた検証の結果、統計的な有意差が被災域とそれ以外の領域の間に示された。これをもとにしたアルゴリズムであれば、普段から頻繁に水域が変動する低湿地帯において、従来より確実かつ迅速な洪水被害把握の実現につながるものと期待される。

 

Syllabus

Teaching Experience

  • Environmental information visualization

    Tokyo City University  

    2022.04
    -
    Now
     

  • リモートセンシング実習1(光学)

    Nihon University  

    2021.04
    -
    Now
     

  • リモートセンシング実習2(SAR)

    Nihon University  

    2020.10
    -
    Now
     

  • 衛星地球観測学演習

    Waseda University  

    2019.04
    -
    Now
     

  • 情報地球科学

    Waseda University  

    2019.04
    -
    Now
     

  • 衛星地球観測学基礎演習

    Waseda University  

    2018.10
    -
    Now
     

  • 惑星地球科学入門

    Waseda University  

    2018.04
    -
    Now
     

  • 地球科学演習

    Waseda University  

    2018.04
    -
    Now
     

  • 衛星地球観測学

    Waseda University  

    2018.04
    -
    Now
     

  • 自然環境科学特論D

    Niigata University  

    2019.04
    -
    2019.09
     

  • 地球科学実習(北海道地質調査実習)

    Waseda University  

    2018.04
    -
    2019.09
     

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Committee Memberships

  • 2021.06
    -
    Now

    公益社団法人日本雪氷学会  関東以西支部理事

  • 2015.09
    -
    Now

    公益社団法人日本雪氷学会  「雪氷」編集委員

  • 2020.04
    -
    2022.03

    佐賀県立宇宙科学館《ゆめぎんが》  宇宙教育プロジェクト有識者委員

Social Activities

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Media Coverage

  • 東京のシンボル・スカイツリー、どこまで離れて見えるか!?

    TV or radio program

    日本テレビ   「ザ!鉄腕!DASH!!」  

    https://www.ntv.co.jp/dash/articles/65yghpz9190fz3g0cm.html  

    2021.05

  • コズミック フロント☆NEXT「宇宙から診断 地球の健康チェック」

    TV or radio program

    Author: Myself  

    NHK/BSプレミアム   コズミックフロント⭐︎NEXT  

    2020.01

     View Summary

    地球は、国際宇宙ステーション(ISS)を始め、4400もの人工衛星から常に観測されている。そこで観測されたデータをもとに各分野の専門家が分析。地球の現状を「診断」し、その「処方薬」をプレゼンしていく。