Advancing global river hydrodynamic simulations using satellite surface water observations

• Project/Area Number: 20H02251
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 22040:Hydroengineering-related
• Research Institution: The University of Tokyo
• Principal Investigator: Yamazaki Dai 東京大学, 生産技術研究所, 准教授 (70736040)
• Co-Investigator(Kenkyū-buntansha): 木田 新一郎 九州大学, 応用力学研究所, 准教授 (50543229)
• Project Period (FY): 2020-04-01 – 2024-03-31
• Project Status: Completed (Fiscal Year 2023)
• Budget Amount: ¥16,900,000 (Direct Cost: ¥13,000,000、Indirect Cost: ¥3,900,000); Fiscal Year 2023: ¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000); Fiscal Year 2022: ¥5,590,000 (Direct Cost: ¥4,300,000、Indirect Cost: ¥1,290,000); Fiscal Year 2021: ¥4,810,000 (Direct Cost: ¥3,700,000、Indirect Cost: ¥1,110,000); Fiscal Year 2020: ¥1,690,000 (Direct Cost: ¥1,300,000、Indirect Cost: ¥390,000)
• Keywords: グローバル河川モデル / 衛星観測 / 精度評価 / モデルベンチマーク / グローバル水文学 / 全球河川モデル

Outline of Research at the Start

本研究は、最先端の全球河川モデルによる河川流量・水位・浸水域のシミュレーションを、衛星による様々な地表水観測データと比較する手法を確立し、衛星地表水観測の不確実性を考慮しつつ、地球規模で河川水動態シミュレーションの精度検証とモデル更正を行うシステム世界に先駆けて構築する。以上により、地球全域を対象に最適化された次世代の全球河川モデルを完成させ、全球河川モデルによる洪水予測の精度を大幅に向上させる。

Outline of Final Research Achievements

In this study, we accomplished the following three things in order to further improve the global river model and lead to quantitative elucidation of the global water cycle.
[1] We established a method for validly comparing a variety of satellite surface water observation data with different characteristics with calculated values from a global river model while taking uncertainty into account. [2] We constructed an algorithm to inversely estimate river channel cross-section parameters using satellite observation data and error information of model estimates. It was shown that robust parameter estimation can be performed even when there is bias in river runoff. [3] We have developed a "Global River Model Benchmark System" that systematically evaluates river simulations using satellite and field observation data across the globe.

Academic Significance and Societal Importance of the Research Achievements

地球規模での河川流れをシミュレーションする全球河川モデルは、広域を対象にした洪水予測警報システムや洪水リスク評価に用いられるほか、気候モデルの一要素として陸域の水循環・物質循環を表現する役割を担うなど、幅広い学術研究で用いられる地球科学の基盤的ツールである。一方で、グローバル洪水モデルの精度評価は十分行われておらず、計算はできるが信頼性が不明という状況が長く続いていた。本研究で衛星観測データによってグローバル洪水モデルの性能を評価する手法を確立し、システマティックな精度ベンチマークを実現したことで、より精緻な洪水予測や気候変動予測の実現につながると考えられる。

Research Products

• [Int'l Joint Research] LEGOS(フランス)
• [Int'l Joint Research] パリ天文台(フランス)
• [Int'l Joint Research] LEGOS/CNES/Echole Polytechnique(フランス)
• [Journal Article] AltiMaP: altimetry mapping procedure for hydrography data (2024)
  • Author(s): Revel Menaka、Zhou Xudong、Modi Prakat、Cretaux Jean-Fran?ois、Calmant Stephane、Yamazaki Dai
  • Journal Title: Earth System Science Data Volume: 16 Issue: 1 Pages: 75-88
  • DOI: 10.5194/essd-16-75-2024
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Benchmark Framework for Global River Model (Version 1.0) (2024)
  • Author(s): Zhou Xudong、Yamazaki Dai、Revel Menaka、Zhao Gang、Modi Prakat
  • Journal Title: ESS OpenArchive Volume: n/a
  • DOI: 10.22541/essoar.171255743.38640796/v1
  • Open Access / Int'l Joint Research
• [Journal Article] Assimilation of transformed water surface elevation to improve river discharge estimation in a continental-scale river (2023)
  • Author(s): Revel Menaka、Zhou Xudong、Yamazaki Dai、Kanae Shinjiro
  • Journal Title: Hydrology and Earth System Sciences Volume: 27 Issue: 3 Pages: 647-671
  • DOI: 10.5194/hess-27-647-2023
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Correction of River Bathymetry Parameters Using the Stage?Discharge Rating Curve (2022)
  • Author(s): Zhou Xudong、Revel Menaka、Modi Prakat、Shiozawa Takuto、Yamazaki Dai
  • Journal Title: Water Resources Research Volume: 58 Issue: 4
  • DOI: 10.1029/2021wr031226
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Toward Improved Comparisons Between Land‐Surface‐Water‐Area Estimates From a Global River Model and Satellite Observations (2021)
  • Author(s): Zhou Xudong、Prigent Catherine、Yamazaki Dai
  • Journal Title: Water Resources Research Volume: 57 Issue: 5
  • DOI: 10.1029/2020wr029256
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] The uncertainty of flood frequency analyses in hydrodynamic model simulations (2021)
  • Author(s): Xudong Zhou, Wenchao Ma, Wataru Echizenya, Dai Yamazaki
  • Journal Title: Natural Hazards and Earth System Sciences Volume: 21 Issue: 3 Pages: 1071-1085
  • DOI: 10.5194/nhess-21-1071-2021
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] A Framework for Estimating Global‐Scale River Discharge by Assimilating Satellite Altimetry (2021)
  • Author(s): Revel Menaka、Ikeshima Daiki、Yamazaki Dai、Kanae Shinjiro
  • Journal Title: Water Resources Research Volume: 57 Issue: 1
  • DOI: 10.1029/2020wr027876
  • Peer Reviewed / Open Access
• [Presentation] A Benchmarking System for Global River Models (2023)
  • Author(s): Xudong Zhou, Dai Yamazaki
  • Organizer: Global Flood Partnership 2023 Conference
  • Int'l Joint Research
• [Presentation] Leveraging SWOT Observations for Improved Water Management: Data Assimilation of Human-Regulated River Discharge in Large Rivers (2023)
  • Author(s): M Revel, J Boulange, N Hanasaki, D Yamazaki
  • Organizer: AGU Fall Meeting 2023
  • Int'l Joint Research
• [Presentation] Global Discharge Estimation by Assimilating Satellite Altimetry with the Current Limitations of the Hydrodynamic Models in the perspective of SWOT mission (2022)
  • Author(s): Menaka Revel, Xudong Zhou, Dai Yamazaki, Shinjiro Kanae
  • Organizer: AGU Fall Meeting 2022
  • Int'l Joint Research
• [Presentation] Prospects of Assimilating Remote Sensing Data into a Hydrodynamic Model in Amazon Basin (2022)
  • Author(s): Menaka Revel, Xudong Zhou, Dai Yamazaki, Shinjiro Kanae
  • Organizer: JpGU 2022
  • Int'l Joint Research
• [Presentation] A framework for benchmarking global flood models. (2022)
  • Author(s): Xudong Zhou, Menaka Revel, Prakat Modi, Dai Yamazaki
  • Organizer: AGU Fall Meeting 2022
  • Int'l Joint Research
• [Presentation] Potential of Assimilating Satellite Altimetry Data in to a Continental-Scale River Routing Model (2021)
  • Author(s): Menaka Revel and Dai Yamazaki
  • Organizer: AGU Fall Meeting 2021
  • Int'l Joint Research
• [Presentation] Direct comparison of surface water dynamics between models and satellites achieved by the latest global river model [CaMa-Flood ver.4] (2021)
  • Author(s): Dai Yamazaki, Xudong Zhou, Menaka Revel, Prakat Modi
  • Organizer: AGU Fall Meeting 2021
  • Int'l Joint Research
• [Presentation] Recent advances in global-scale surface water hydrodynamics modelling (2021)
  • Author(s): Dai Yamazaki
  • Organizer: AGOS Kamide Distinguished Lecture
  • Int'l Joint Research / Invited
• [Presentation] Estimating River Discharge by Assimilating SWOT Observations using a Physically Based Empirical Localization Method (2020)
  • Author(s): Menaka Revel, Dai Yamazaki
  • Organizer: AGU (American Geophysical Union) Fall Meeting 2020
  • Int'l Joint Research
• [Presentation] MERIT DEM Performs Better for Hydrodynamic Flood Model in Amazon Basin (2020)
  • Author(s): Prakat Modi, Menaka Revel, Dai Yamazaki
  • Organizer: AGU (American Geophysical Union) Fall Meeting 2020
  • Int'l Joint Research
• [Presentation] How can we reasonably compare the water surface area between models & satellites (2020)
  • Author(s): Xudong Zhou, Dai Yamazaki
  • Organizer: AGU (American Geophysical Union) Fall Meeting 2020
  • Int'l Joint Research
• [Remarks] 河川観測データ配置ツール「AllocRiverGauge v1.0」
  • URL: https://github.com/global-hydrodynamics/AllocRiverGauge/tree/release_v1.0
• [Remarks] 衛星高度計データ配置ツール「AltiMap」
  • URL: https://github.com/MenakaRevel/AltiMaP
• [Remarks] 全球河川モデルCaMa-Floodwebページ
  • URL: http://hydro.iis.u-tokyo.ac.jp/~yamadai/cama-flood/
• [Remarks] CaMa-Flood version 4
  • URL: https://github.com/global-hydrodynamics/CaMa-Flood_v4