NAGAI, Hiroto

写真a

Affiliation

Faculty of Education and Integrated Arts and Sciences, School of Education

Job title

Assistant Professor(without tenure)

Homepage URL

http://nagy-lab.skr.jp

Profile

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 【 display / non-display

  • 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 【 display / non-display

  • Nagoya Univ.   Doctor of Environmental study

Research Experience 【 display / non-display

  • 2021.08
    -
    Now

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

  • 2020.04
    -
    Now

    日本大学   文理学部   非常勤講師

  • 2018.07
    -
    Now

    NIED   Guest Researcher

  • 2018.04
    -
    Now

    Waseda University   Department of Education   Lecturer

  • 2019.04
    -
    2019.09

    新潟大学   非常勤講師

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Professional Memberships 【 display / non-display

  •  
     
     

    THE JAPANESE SOCIETY OF SNOW AND ICE

  •  
     
     

    THE REMOTE SENSING SOCIETY OF JAPAN

 

Research Areas 【 display / non-display

  • Science education   Earth observation data for education

  • Disaster prevention engineering   Hazard response with satellite data and GIS

  • Environmental dynamic analysis   Remote sensing of environment

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

Research Interests 【 display / non-display

  • 衛星地球観測学

  • 合成開口レーダー

  • Google Earth Engine

  • NoBADI

  • SINOBi

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Papers 【 display / non-display

  • 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

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Books and Other Publications 【 display / non-display

  • 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 【 display / non-display

  • 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

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Other 【 display / non-display

  • 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)

Awards 【 display / non-display

  • 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 【 display / non-display

  • 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

    Project Year :

    2019.04
    -
    2022.03
     

    Hiroto NAGAI

    Authorship: Principal investigator

  • 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

    Project Year :

    2016.04
    -
    2021.03
     

    Hiroto NAGAI

    Authorship: Principal investigator

  • 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

    Project Year :

    2019.05
    -
    2020.03
     

    Hiroto NAGAI

    Authorship: Principal investigator

  • 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

    Project Year :

    2018.04
    -
    2020.03
     

    Hiroto NAGAI

    Authorship: Principal investigator

  • 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

    Project Year :

    2018
    -
    2019.03
     

    山口悟

Presentations 【 display / non-display

  • 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

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Specific Research 【 display / non-display

  • 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 【 display / non-display

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Teaching Experience 【 display / non-display

  • 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
     

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Committee Memberships 【 display / non-display

  • 2021.06
    -
    Now

    公益社団法人日本雪氷学会  関東以西支部理事

  • 2020.04
    -
    Now

    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

  • 2015.09
    -
    Now

    公益社団法人日本雪氷学会  「雪氷」編集委員

Social Activities 【 display / non-display

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Media Coverage 【 display / non-display

  • 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。