Details of the Researcher

PHOTO

Daisuke Takasuka
Section
Graduate School of Science
Job title
Assistant Professor
Degree

  • Ph.D. (Science) (The University of Tokyo)

e-Rad No.
71001666

Research History 4

  • 2024/04 - Present
    Tohoku University　Graduate School of Science Department of Geophysics　Assistant Professor

  • 2022/10 - 2024/03
    The University of Tokyo　Atmosphere and Ocean Research Institute Division of Climate System Research

  • 2021/04 - 2022/10
    Japan Agency for Marine-Earth Science and Technology

  • 2020/04 - 2021/03
    Ochanomizu University　JSPS Research Fellow (PD)

Committee Memberships 6

  • World Climate Research Programme (WCRP)　Co-chairs of the Digital Earths Lighthouse Activity working group on km-scale modeling

    2026/03 - Present

  • Global Energy and Water Exchanges (GEWEX)　Co-Leader of the GEWEX/GASS Diurnal Cycle of Precipitation Project

    2025/11 - Present

  • 日本気象学会　松野賞候補者推薦委員会

    2024/07 - Present

  • 日本気象学会　国際学術交流委員会

    2024/07 - Present

  • 日本気象学会　英文レター誌SOLA 編集委員

    2024/07 - Present

  • World Meteorological Organization, Working Group on Numerical Experimentation　MJO Task Force member

    2023/04 - Present

Show all ︎Show first 5

Research Areas 1

  • Natural sciences / Atmospheric and hydrospheric science /

Awards 4

  1. Early career researcher competition winner

    2024/07　World Climate Research Programme (WCRP), GEWEX

  2. 松野賞

    2019/07　日本気象学会

  3. 学生優秀発表賞

    2019/05　日本地球惑星科学連合

  4. 研究奨励賞（修士）

    2017/03　東京大学大学院理学系研究科

Papers 25

  1. Resolution dependence of the climate feedback parameter in km-scale climate models

    Angel Peinado Bravo, Masaki Toda, Hauke Schmidt, Sandrine Bony, Sarah M. Kang, Daniel Klocke, Lukas Kluft, Bjorn Stevens, Daisuke Takasuka, Angel Peinado Bravo

    2026/06/09

    DOI： 10.22541/essoar.15004534/v1 　

  2. Hacking Km-Scale Models: A Participative Model for Climate Information Peer-reviewed

    Andrew Gettelman, Pier Luigi Vidale, Bjorn Stevens, Florian Ziemen, Zhe Feng, Heike Konow, Tobias Kölling, Lukas Kluft, William Jones, Sara Pasqualetto, Yuting Wu, Saskia Brose, John Clyne, Lluís Fita, Samuel Green, Lucas Harris, Melissa Anne Hart, Julia Kukulies, Brian Medeiros, Timothy M. Merlis, Mark Muetzelfeldt, Robert Pincus, Rosmeri P. da Rocha, Masaki Satoh, Hang Su, Daisuke Takasuka, Chris Terai, Paul Ullrich, Tianjun Zhou

    Bulletin of the American Meteorological Society　2026/04/28

    Publisher: American Meteorological Society

    DOI： 10.1175/bams-d-25-0183.1 　

    ISSN： 0003-0007

    eISSN： 1520-0477

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    Abstract In May 2025 nearly 700 participants from all around the world coalesced at 10 regional nodes, and a few satellite nodes, to take part in a global hackathon of km-scale (horizontal grid spacing < 10 km) regional and global Earth System Models. Exciting science is emerging from these efforts, ranging across novel model analysis, new ways of integrating with satellite data, and emulation with machine learning. New technologies were trialed that enable the community to work in new and complementary ways to democratize access to global information at a local scale from a set of the world's highest-resolution climate models. The hackathon demonstrated how exascale data can be organized to be accessible to anyone. Fundamentally, the community could apply these techniques and technologies to move towards more participative models for co-production and delivery of diverse sources of climate information for climate scientists and citizens alike.

  3. Climate and ocean circulation changes toward a modern snowball Earth Peer-reviewed

    Takashi Obase, Takanori Kodama, Takao Kawasaki, Sam Sherriff-Tadano, Daisuke Takasuka, Ayako Abe-Ouchi, Masakazu Fujii

    Climate of the Past　22　845-859　2026/04/20

    DOI： 10.5194/cp-22-845-2026 　

  4. Machine learning prediction of the Madden–Julian oscillation using reservoir computing Peer-reviewed

    Tamaki Suematsu, Kengo Nakai, Tsuyoshi Yoneda, Daisuke Takasuka, Takuya Jinno, Yoshitaka Saiki, Hiroaki Miura

    Japan Journal of Industrial and Applied Mathematics　43　(2)　2026/03/19

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1007/s13160-026-00770-5 　

    ISSN： 0916-7005

    eISSN： 1868-937X

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    Abstract The prediction of the Madden–Julian Oscillation (MJO), a massive tropical weather event with global socio-economic impacts, has been infamously difficult with physics-based weather prediction models. We employ the reservoir computing, a brain-inspired machine-learning technique, to construct a machine learning model that forecasts the real-time multivariate MJO index (RMM), a macroscopic variable that represents the state of the MJO. The training data was refined by development of a novel real-time band-pass filter that extracts the recurrency of MJO signals only from the past raw atmospheric data, and by selection of a suitable time-delay coordinate of the RMM that enhances the recurrency of the input data. The constructed model demonstrated the skill to forecast the time sequence of the RMM for a month from pre-developmental stages of the MJO. Examination of best-performing cases suggested that RMM sequences may be predicted for over two months in some cases. These results imply that inherent predictability limit of the MJO is longer than that has been estimated from physics-based weather prediction models.

  5. Precipitation Characteristics and Thermodynamic‐Convection Coupling in Global Kilometer‐Scale Simulations Peer-reviewed

    Daisuke Takasuka, Tobias Becker, Jiawei Bao

    Journal of Advances in Modeling Earth Systems　2026/03

    DOI： 10.1029/2025MS005343 　

  6. Propagation of the Madden–Julian oscillation as a deterministic chaotic phenomenon Peer-reviewed

    Daisuke Takasuka, Tamaki Suematsu, Hiroaki Miura, Masuo Nakano

    Science Advances　2026/02/18

    DOI： 10.1126/sciadv.adz1916 　

  7. Tropics-wide intraseasonal oscillations Peer-reviewed

    Jiawei Bao, Sandrine Bony, Daisuke Takasuka, Caroline Muller

    Proceedings of the National Academy of Sciences　122　(48)　2025/11/24

    Publisher: Proceedings of the National Academy of Sciences

    DOI： 10.1073/pnas.2511549122 　

    ISSN： 0027-8424

    eISSN： 1091-6490

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    The tropical climate variability is characterized by various oscillations across a range of timescales. Oscillations that imprint the tropical mean state are generally attributed to slow processes, such as the seasonal cycle or interannual variability. Here, we identify a pronounced tropics-wide intraseasonal oscillation (TWISO) in satellite observations and reanalyses. This oscillation, with a period of 30 to 60 d, is evident across multiple variables and involves interactions between convection, radiation, surface fluxes, and large-scale circulation. It is primarily manifested as convective perturbations in the tropical Indo-Pacific warm pool accompanied by oscillations in the large-scale tropical overturning circulation. Here, we examine the relationship between TWISO, the Madden–Julian Oscillation (MJO), and the instability of radiative-convective equilibrium. Certain phases of TWISO coincide with specific phases of the MJO, suggesting a potential connection between the two. However, although the MJO can amplify the oscillation amplitude of TWISO, it is not essential for TWISO to occur. Finally, due to its broad manifestation across the tropics, TWISO potentially exerts widespread influence on tropical weather and climate at regional scales.

  8. nextGEMS: entering the era of kilometer-scale Earth system modeling Peer-reviewed

    Hans Segura, Xabier Pedruzo-Bagazgoitia, Philipp Weiss, Sebastian K. Müller, Thomas Rackow, Junhong Lee, Edgar Dolores-Tesillos, Imme Benedict, Matthias Aengenheyster, Razvan Aguridan, Gabriele Arduini, Alexander J. Baker, Jiawei Bao, Swantje Bastin, Eulàlia Baulenas, Tobias Becker, Sebastian Beyer, Hendryk Bockelmann, Nils Brüggemann, Lukas Brunner, Suvarchal K. Cheedela, Sushant Das, Jasper Denissen, Ian Dragaud, Piotr Dziekan, Madeleine Ekblom, Jan Frederik Engels, Monika Esch, Richard Forbes, Claudia Frauen, Lilli Freischem, Diego García-Maroto, Philipp Geier, Paul Gierz, Álvaro González-Cervera, Katherine Grayson, Matthew Griffith, Oliver Gutjahr, Helmuth Haak, Ioan Hadade, Kerstin Haslehner, Shabeh ul Hasson, Jan Hegewald, Lukas Kluft, Aleksei Koldunov, Nikolay Koldunov, Tobias Kölling, Shunya Koseki, Sergey Kosukhin, Josh Kousal, Peter Kuma, Arjun U. Kumar, Rumeng Li, Nicolas Maury, Maximilian Meindl, Sebastian Milinski, Kristian Mogensen, Bimochan Niraula, Jakub Nowak, Divya Sri Praturi, Ulrike Proske, Dian Putrasahan, René Redler, David Santuy, Domokos Sármány, Reiner Schnur, Patrick Scholz, Dmitry Sidorenko, Dorian Spät, Birgit Sützl, Daisuke Takasuka, Adrian Tompkins, Alejandro Uribe, Mirco Valentini, Menno Veerman, Aiko Voigt, Sarah Warnau, Fabian Wachsmann, Marta Wacławczyk, Nils Wedi, Karl-Hermann Wieners, Jonathan Wille, Marius Winkler, Yuting Wu, Florian Ziemen, Janos Zimmermann, Frida A.-M. Bender, Dragana Bojovic, Sandrine Bony, Simona Bordoni, Patrice Brehmer, Marcus Dengler, Emanuel Dutra, Saliou Faye, Erich Fischer, Chiel van Heerwaarden, Cathy Hohenegger, Heikki Järvinen, Markus Jochum, Thomas Jung, Johann H. Jungclaus, Noel S. Keenlyside, Daniel Klocke, Heike Konow, Martina Klose, Szymon Malinowski, Olivia Martius, Thorsten Mauritsen, Juan Pedro Mellado, Theresa Mieslinger, Elsa Mohino, Hanna Pawłowska, Karsten Peters-von Gehlen, Abdoulaye Sarré, Pajam Sobhani, Philip Stier, Lauri Tuppi, Pier Luigi Vidale, Irina Sandu, Bjorn Stevens

    Geoscientific Model Development　18　(20)　7735-7761　2025/10/23

    Publisher: Copernicus GmbH

    DOI： 10.5194/gmd-18-7735-2025 　

    eISSN： 1991-9603

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    Abstract. The Next Generation of Earth Modeling Systems (nextGEMS) project aimed to produce multidecadal climate simulations, for the first time, with resolved kilometer-scale (km-scale) processes in the ocean, land, and atmosphere. In only 3 years, nextGEMS achieved this milestone with the two km-scale Earth system models, ICOsahedral Non-hydrostatic model (ICON) and Integrated Forecasting System coupled to the Finite-volumE Sea ice-Ocean Model (IFS-FESOM). nextGEMS was based on three cornerstones: (1) developing km-scale Earth system models with small errors in the energy and water balance, (2) performing km-scale climate simulations with a throughput greater than 1 simulated year per day, and (3) facilitating new workflows for an efficient analysis of the large simulations with common data structures and output variables. These cornerstones shaped the timeline of nextGEMS, divided into four cycles. Each cycle marked the release of a new configuration of ICON and IFS-FESOM, which were evaluated at hackathons. The hackathon participants included experts from climate science, software engineering, and high-performance computing as well as users from the energy and agricultural sectors. The continuous efforts over the four cycles allowed us to produce 30-year simulations with ICON and IFS-FESOM, spanning the period 2020–2049 under the SSP3-7.0 scenario. The throughput was about 500 simulated days per day on the Levante supercomputer of the German Climate Computing Center (DKRZ). The simulations employed a horizontal grid of about 5 km resolution in the ocean and 10 km resolution in the atmosphere and land. Aside from this technical achievement, the simulations allowed us to gain new insights into the realism of ICON and IFS-FESOM. Beyond its time frame, nextGEMS builds the foundation of the Climate Change Adaptation Digital Twin developed in the Destination Earth initiative and paves the way for future European research on climate change.

  9. What Is the Role of Air-Sea Interaction in the Intra-Seasonal Fluctuation of the Monsoon Trough over the Western North Pacific? Peer-reviewed

    Yutaro NIRASAWA, Tomoki MIYAKAWA, Daisuke TAKASUKA, Takao KAWASAKI, Ryusuke MASUNAGA

    Journal of the Meteorological Society of Japan. Ser. II　103　(6)　679-706　2025/09

    Publisher: Meteorological Society of Japan

    DOI： 10.2151/jmsj.2025-035 　

    ISSN： 0026-1165

    eISSN： 2186-9057

  10. ENSO and QBO Controls the Favorableness of the MJO Realization Cooperatively Peer-reviewed

    Daisuke Takasuka, Tsubasa Kohyama, Tamaki Suematsu, Hiroaki Miura

    Journal of Geophysical Research: Atmospheres　130　(2)　2025/01/28

    DOI： 10.1029/2024JD042116 　

  11. Multi-year simulations at kilometre scale with the Integrated Forecasting System coupled to FESOM2.5 and NEMOv3.4 Peer-reviewed

    Thomas Rackow, Xabier Pedruzo-Bagazgoitia, Tobias Becker, Sebastian Milinski, Irina Sandu, Razvan Aguridan, Peter Bechtold, Sebastian Beyer, Jean Bidlot, Souhail Boussetta, Willem Deconinck, Michail Diamantakis, Peter Dueben, Emanuel Dutra, Richard Forbes, Rohit Ghosh, Helge F. Goessling, Ioan Hadade, Jan Hegewald, Thomas Jung, Sarah Keeley, Lukas Kluft, Nikolay Koldunov, Aleksei Koldunov, Tobias Kölling, Josh Kousal, Christian Kühnlein, Pedro Maciel, Kristian Mogensen, Tiago Quintino, Inna Polichtchouk, Balthasar Reuter, Domokos Sármány, Patrick Scholz, Dmitry Sidorenko, Jan Streffing, Birgit Sützl, Daisuke Takasuka, Steffen Tietsche, Mirco Valentini, Benoît Vannière, Nils Wedi, Lorenzo Zampieri, Florian Ziemen

    Geoscientific Model Development　18　(1)　33-69　2025/01/10

    Publisher: Copernicus GmbH

    DOI： 10.5194/gmd-18-33-2025 　

    eISSN： 1991-9603

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    Abstract. We report on the first multi-year kilometre-scale global coupled simulations using ECMWF's Integrated Forecasting System (IFS) coupled to both the NEMO and FESOM ocean–sea ice models, as part of the H2020 Next Generation Earth Modelling Systems (nextGEMS) project. We focus mainly on an unprecedented IFS-FESOM coupled setup, with an atmospheric resolution of 4.4 km and a spatially varying ocean resolution that reaches locally below 5 km grid spacing. A shorter coupled IFS-FESOM simulation with an atmospheric resolution of 2.8 km has also been performed. A number of shortcomings in the original numerical weather prediction (NWP)-focused model configurations were identified and mitigated over several cycles collaboratively by the modelling centres, academia, and the wider nextGEMS community. The main improvements are (i) better conservation properties of the coupled model system in terms of water and energy budgets, which also benefit ECMWF's operational 9 km IFS-NEMO model; (ii) a realistic top-of-the-atmosphere (TOA) radiation balance throughout the year; (iii) improved intense precipitation characteristics; and (iv) eddy-resolving features in large parts of the mid- and high-latitude oceans (finer than 5 km grid spacing) to resolve mesoscale eddies and sea ice leads. New developments at ECMWF for a better representation of snow and land use, including a dedicated scheme for urban areas, were also tested on multi-year timescales. We provide first examples of significant advances in the realism and thus opportunities of these kilometre-scale simulations, such as a clear imprint of resolved Arctic sea ice leads on atmospheric temperature, impacts of kilometre-scale urban areas on the diurnal temperature cycle in cities, and better propagation and symmetry characteristics of the Madden–Julian Oscillation.

  12. A protocol and analysis of year-long simulations of global storm-resolving models and beyond Peer-reviewed

    Daisuke Takasuka, Masaki Satoh, Tomoki Miyakawa, Chihiro Kodama, Daniel Klocke, Bjorn Stevens, Pier Luigi Vidale, Christopher R. Terai

    Progress in Earth and Planetary Science　11　(1)　2024/12/19

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1186/s40645-024-00668-1 　

    eISSN： 2197-4284

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    Abstract We propose a protocol to evaluate and analyze year-long simulations of global storm-resolving models (GSRMs). The proposed protocol complements an earlier 40-day simulation protocol under the DYAMOND (DYnamics of the Atmospheric general circulation Modeled On Non-hydrostatic Domains) project to allow the analysis of the seasonal cycle and associated climatic relevant phenomena. This intercomparison aims to reveal how GSRMs, which can simulate mesoscale convective systems (MCSs) in the global domain, reproduce atmospheric large-scale structures related to convection beyond month-long simulations. The intercomparison for one-year simulations is conducted by either atmosphere-only models or atmosphere–ocean coupled models with atmospheric horizontal mesh sizes less than 5 km. We recommend the continuous four seasons from March 2020 to February 2021 as a target period for the intercomparison but with options for many groups to join more flexibly. The output variables are collected at 0.25° resolution, and archives of a small set of native grid variables are encouraged to analyze tropical cyclones and MCSs. Through the proposed global storm-resolving simulation, we will evaluate the climatological distributions of the atmospheric large-scale circulations, such as the Intertropical Convergence Zone (ITCZ), monsoon, midlatitude jets, their time evolution, and the upscale impacts on them. We present sample analyses from a one-year simulation using the 3.5 km mesh Nonhydrostatic Icosahedral Atmospheric Model (NICAM), revealing the realistic zonal contrast of tropical precipitation, no double ITCZ structure, the reasonable midlatitude jet position and intensity but a weak bias of storm track activities, and a warm bias over the Eurasia during boreal winter. We also clarify the cross-scale interaction, such as the effects of cold pools on mean precipitation over the Maritime Continent through the precipitation diurnal cycle and the effects of resolved gravity waves on midlatitude mean flows. The proposed one-year simulation protocol is referred to as the “Sendai Protocol.” This protocol is not unique or definite for evaluating GSRMs; we prospect a hierarchical set of experiments from short-term to multi-year simulations as GSRM intercomparisons.

  13. How Can We Improve the Seamless Representation of Climatological Statistics and Weather Toward Reliable Global K‐Scale Climate Simulations? Peer-reviewed

    Daisuke Takasuka, Chihiro Kodama, Tamaki Suematsu, Tomoki Ohno, Yohei Yamada, Tatsuya Seiki, Hisashi Yashiro, Masuo Nakano, Hiroaki Miura, Akira T. Noda, Tomoe Nasuno, Tomoki Miyakawa, Ryusuke Masunaga

    Journal of Advances in Modeling Earth Systems　2024/02

    DOI： 10.1029/2023MS003701 　

  14. Parallelized Remapping Algorithms for km-scale Global Weather and Climate Simulations with Icosahedral Grid System Peer-reviewed

    Chihiro Kodama, Hisashi Yashiro, Takashi Arakawa, Daisuke Takasuka, Shuhei Matsugishi, Hirofumi Tomita

    Proceedings of the International Conference on High Performance Computing in Asia-Pacific Region　2024/01/18

    Publisher: ACM

    DOI： 10.1145/3635035.3635040 　

  15. Asymptotic Matching between Weather and Climate Models Peer-reviewed

    Hiroaki Miura, Tamaki Suematsu, Yuta Kawai, Yoko Yamagami, Daisuke Takasuka, Yuki Takano, Ching-Shu Hung, Kazuya Yamazaki, Chihiro Kodama, Yoshiyuki Kajikawa, Yukio Masumoto

    Bulletin of the American Meteorological Society　104　(12)　E2308-E2315　2023/12

    Publisher: American Meteorological Society

    DOI： 10.1175/bams-d-22-0128.1 　

    ISSN： 0003-0007

    eISSN： 1520-0477

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    Abstract The Deep Numerical Analysis for Climate (DNA-Climate) is a pilot project to develop an Earth system model on a kilometer-scale horizontal mesh. The acronym “DNA” is based on the analogies between the hierarchical structures of atmospheric phenomena and living organisms. The multiscale structure of clouds and circulations may be analogous to the multiscale structure of cells and organs organized according to the blueprint, deoxyribonucleic acid (DNA). Whereas global cloud-resolving models (CRMs) can produce better solutions on shorter time scales that are decisively governed by the initial conditions, global climate models (GCMs) may generate reliable solutions on longer time scales that are largely determined to balance energy inputs and outputs. Our challenge is to build a physically valid model that consistently bridges the shorter- and longer-time-scale solutions in the intermediate time scales. Research topics of DNA-Climate are configured in consideration of the structural similarity between the climate modeling and the technique of matched asymptotic expansions in mathematics. The central question is whether a single modeling framework using only either global CRM or GCM will work adequately at all time scales of climate, or whether a multiscale modeling framework combining several models, of which each is only valid for limited time scales, will be needed. A multiscale modeling is an attractive framework for advancing climate modeling and would be an intriguing topic to be studied in parallel with global CRMs and GCMs.

  16. CERESMIP: a climate modeling protocol to investigate recent trends in the Earth's Energy Imbalance Peer-reviewed

    Gavin A. Schmidt, Timothy Andrews, Susanne E. Bauer, Paul J. Durack, Norman G. Loeb, V. Ramaswamy, Nathan P. Arnold, Michael G. Bosilovich, Jason Cole, Larry W. Horowitz, Gregory C. Johnson, John M. Lyman, Brian Medeiros, Takuro Michibata, Dirk Olonscheck, David Paynter, Shiv Priyam Raghuraman, Michael Schulz, Daisuke Takasuka, Vijay Tallapragada, Patrick C. Taylor, Tilo Ziehn

    Frontiers in Climate　5　2023/07/03

    Publisher: Frontiers Media SA

    DOI： 10.3389/fclim.2023.1202161 　

    eISSN： 2624-9553

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    The Clouds and the Earth's Radiant Energy System (CERES) project has now produced over two decades of observed data on the Earth's Energy Imbalance (EEI) and has revealed substantive trends in both the reflected shortwave and outgoing longwave top-of-atmosphere radiation components. Available climate model simulations suggest that these trends are incompatible with purely internal variability, but that the full magnitude and breakdown of the trends are outside of the model ranges. Unfortunately, the Coupled Model Intercomparison Project (Phase 6) (CMIP6) protocol only uses observed forcings to 2014 (and Shared Socioeconomic Pathways (SSP) projections thereafter), and furthermore, many of the ‘observed' drivers have been updated substantially since the CMIP6 inputs were defined. Most notably, the sea surface temperature (SST) estimates have been revised and now show up to 50% greater trends since 1979, particularly in the southern hemisphere. Additionally, estimates of short-lived aerosol and gas-phase emissions have been substantially updated. These revisions will likely have material impacts on the model-simulated EEI. We therefore propose a new, relatively low-cost, model intercomparison, CERESMIP, that would target the CERES period (2000-present), with updated forcings to at least the end of 2021. The focus will be on atmosphere-only simulations, using updated SST, forcings and emissions from 1990 to 2021. The key metrics of interest will be the EEI and atmospheric feedbacks, and so the analysis will benefit from output from satellite cloud observation simulators. The Tier 1 request would consist only of an ensemble of AMIP-style simulations, while the Tier 2 request would encompass uncertainties in the applied forcing, atmospheric composition, single and all-but-one forcing responses. We present some preliminary results and invite participation from a wide group of models.

  17. Climate of High-obliquity Exoterrestrial Planets with a Three-dimensional Cloud System Resolving Climate Model Peer-reviewed

    Takanori Kodama, Daisuke Takasuka, Sam Sherriff-Tadano, Takeshi Kuroda, Tomoki Miyakawa, Ayako Abe-Ouchi, Masaki Satoh

    The Astrophysical Journal　2022/11/01

    DOI： 10.3847/1538-4357/ac98ae 　

  18. Deceleration of Madden-Julian Oscillation Speed in NICAM AMIP-type Simulation Associated with Biases in the Walker Circulation Strength Peer-reviewed

    Tamaki Suematsu, Hiroaki Miura, Chihiro Kodama, Daisuke Takasuka

    Geophysical Research Letters　49　(11)　2022/03/16

    Publisher: American Geophysical Union ({AGU})

    DOI： 10.1002/essoar.10510854.1 　

    ISSN： 0094-8276 1944-8007

  19. MJO Initiation Triggered by Amplification of Upper-tropospheric Dry Mixed Rossby-gravity Waves Peer-reviewed

    Daisuke Takasuka, Tsubasa Kohyama, Hiroaki Miura, Tamaki Suematsu

    Geophysical Research Letters　48　(20)　2021/05/11

    Publisher: American Geophysical Union ({AGU})

    DOI： 10.1002/essoar.10507006.1 　

    ISSN： 0094-8276 1944-8007

  20. Diversity of the Madden–Julian Oscillation: Initiation Region Modulated by the Interaction Between the Intraseasonal and Interannual Variabilities Peer-reviewed

    Daisuke Takasuka, Masaki Satoh

    Journal of Climate　1-65　2021/02/01

    Publisher: American Meteorological Society

    DOI： 10.1175/jcli-d-20-0688.1 　

    ISSN： 0894-8755

  21. A Wall-like Sharp Downward Branch of the Walker Circulation above the Western Indian Ocean Peer-reviewed

    Tsubasa Kohyama, Tamaki Suematsu, Hiroaki Miura, Daisuke Takasuka

    Journal of Geophysical Research: Atmospheres　126　(21)　2021/01/27

    Publisher: American Geophysical Union ({AGU})

    DOI： 10.1002/essoar.10505995.1 　

    ISSN： 2169-897X 2169-8996

  22. Dynamical Roles of Mixed Rossby–Gravity Waves in Driving Convective Initiation and Propagation of the Madden–Julian Oscillation: General Views Peer-reviewed

    Daisuke Takasuka, Masaki Satoh

    Journal of the Atmospheric Sciences　1-63　2020/10/01

    Publisher: American Meteorological Society

    DOI： 10.1175/jas-d-20-0050.1 　

    ISSN： 0022-4928 1520-0469

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    <jats:title>Abstract</jats:title> <jats:p>Motivated by the previous case study, this work shows that dynamical variations of mixed Rossby–gravity waves with tropical depression-type circulations (MRGTDs) are one possible drivers of convective initiation and propagation of the Madden–Julian oscillation (MJO) by performing statistical analysis. MJO events initiated in the Indian Ocean (IO) in boreal winter are objectively identified solely using outgoing longwave radiation data. The lagged-composite analysis of detected MJO events demonstrates that MJO convection is initiated in the southwestern IO (SWIO), where strong MRGTD–convection coupling is statistically found. Further classification of MJO cases in terms of intraseasonal convection and MRGTD activities in the SWIO suggests that 26 of 47 cases are related to more enhanced MRGTDs, although they can also be secondarily affected by Kelvin waves. For those MRGTD-enhanced MJO events, MJO convective initiation is primarily triggered by low-level MRGTD circulations which develop via the enhancement of downward energy dispersion in accordance with upper-tropospheric baroclinic conversion. This is supported by the modulation of MRGTD structure associated with zonal wave contraction due to upper-tropospheric zonal convergence, and plentiful moisture advected into the western IO. Following this MRGTD-induced MJO triggering and mid-tropospheric pre-moistening in the IO contributed by MRGTD shallow circulations as well as intraseasonal winds during the MJO-suppressed phase, low-level MRGTD winds with eastward group velocity successively trigger convection to the east, which helps MJO convective propagation over the IO. The interannual atmospheric variability may affect whether the presented MRGTD-related processes are effective or not.</jats:p>

  23. Observational Evidence of Mixed Rossby‐Gravity Waves as a Driving Force for the MJO Convective Initiation and Propagation Peer-reviewed

    Daisuke Takasuka, Masaki Satoh, Satoru Yokoi

    Geophysical Research Letters　2019/05/28

    DOI： 10.1029/2019GL083108 　

    ISSN： 0094-8276 1944-8007

  24. Initiation Processes of the Tropical Intraseasonal Variability Simulated in an Aqua-Planet Experiment: What is the Intrinsic Mechanism for MJO Onset? Peer-reviewed

    Daisuke Takasuka, Masaki Satoh, Tomoki Miyakawa, Hiroaki Miura

    Journal of Advances in Modeling Earth Systems　10　(4)　1047-1073　2018/04

    Publisher: American Geophysical Union ({AGU})

    DOI： 10.1002/2017ms001243 　

    ISSN： 1942-2466

  25. Topographical Effects on Internally Produced MJO-Like Disturbances in an Aqua-Planet Version of NICAM Peer-reviewed

    Daisuke Takasuka, Tomoki Miyakawa, Masaki Satoh, Hiroaki Miura

    SOLA　11　170-176　2015

    Publisher: Meteorological Society of Japan

    DOI： 10.2151/sola.2015-038 　

    ISSN： 1349-6476

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Misc. 1

  1. 全球雲解像モデルを用いたトラピスト1eの気候

    小玉貴則, 高須賀大輔, 樋口太郎, 黒田剛史

    日本惑星科学会秋季講演会予稿集(Web)　2024　2024

Presentations 13

  1. Mixed Rossby-Gravity Waves as a Robust Precursor to MJO Initiation and Their Extratropical Linkages

    Daisuke Takasuka, Hiroaki Miura

    JpGU-AGU Joint Meeting 2026　2026/05/26

  2. ENSO and QBO Controls the Favorableness of the MJO Realization Cooperatively Invited

    Dasiuke Takasuka, Tsubasa Kohyama, Tamaki Sueamtsu, Hiroaki Miura

    JpGU-AGU Joint Meeting 2026　2026/05/24

  3. Deterministic chaotic behavior in the propagation of the Madden-Julian oscillation

    Daisuke Takasuka, Tamaki Suematsu, Hiroaki Miura, Masuo Nakano

    EGU General Assembly 2026　2026/05/06

  4. Relevance of Global km-scale Modeling for Large-scale Atmospheric Variability: Perspectives from a 10-year NICAM simulation Invited

    Daisuke Takasuka

    CMIP Community Workshop 2026　2026/03/11

  5. Relevance of Global km-scale Modeling for Large-scale Atmospheric Variability: Perspectives from a 10-year NICAM simulation

    Daisuke Takasuka, Chihiro Kodama, Masuo Nakano, Yohei Yamada, Ryusuke Masunaga, Tamaki Suematsu, Hiroaki Miura

    AGU Fall Meeting 2025　2025/12/18

  6. What do we see in the kilometer-scale climate modeling with NICAM?

    Daisuke Takasuka

    7th International Workshop on Nonhydrostatic Numerical Models　2025/11/18

  7. 熱帯域の湿潤対流に対する波動・渦擾乱の役割：MJOを例に Invited

    高須賀大輔

    日本気象学会2025年度秋季大会　2025/11/06

  8. 全球雲解像モデルが紐解くMJOの決定論的カオス性 Invited

    高須賀大輔

    大槌シンポジウム2025：様々な時空間スケールの⼤気現象における普遍性と多様性　2025/08/08

  9. Multi-year climate simulations with km-scale NICAM: Strategies, Successes, and Outooks Invited

    Daisuke Takasuka

    WCRP Lighthouse Activities: Digital Earths webinar series　2024/01/16

  10. The Madden-Julian Oscillation and Associated Cross-scale Interaction Represented in a Kilometer-scale Atmospheric Climate Simulation Invited

    Daisuke Takasuka

    AGU Fall Meeting 2023　2023/12/13

  11. Tackling Errors Toward Realistic Seamless Representation in Kilometer-scale Climate Simulations With NICAM Invited

    Daisuke Takasuka

    IUGG General Assembly 2023　2023/07/15

  12. Recent Progress and Challenges on Global sub-5km mesh Model Experiments from the Sub-seasonal to Climate Scales Invited

    Daisuke Takasuka

    6th WGNE workshop on systematic errors in weather and climate models　2022/11/03

  13. Progress and challenges on high resolution Atmospheric modelling with NICAM Invited

    Daisuke Takasuka

    Workshop on Modeling the Climate System at Ultra-High-Resolution　2022/10/03

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Research Projects 5

  1. 全球雲解像気候モデルと最新の観測で開拓するグローバル極端気象学

    小玉 知央, 高須賀 大輔, 梶川 義幸, 末松 環, 吉田 龍二, 横井 覚, 中野 満寿男, 升永 竜介

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 基盤研究(A)

    Institution: 国立研究開発法人海洋研究開発機構

    2026/04/01 - 2030/03/31

  2. 階層間相互作用から再考するMJOの発生・東進機構とその予測可能性

    高須賀 大輔

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 若手研究

    Institution: 東北大学

    2026/04 - 2029/03

  3. Global warming response of extreme rainfall and the associated hierarchical structure based on global cloud-resolving climate modeling

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Research Activity Start-up

    Institution: Tohoku University

    2024/07/31 - 2026/03/31

  4. マッデン・ジュリアン振動の発生における経年的な間欠性とその環境要因の解明

    高須賀 大輔

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 特別研究員奨励費

    Institution: お茶の水女子大学

    2020/04 - 2021/03

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    マッデン・ジュリアン振動 (MJO) の顕在化頻度が経年的に変動する要因を解明するにあたり、本年度は主に観測に基づく40年分の再解析データを用いて、MJOよりも長い時間スケールで変動する海面水温分布や大気循環の影響に着目した統計解析を行った。インド洋・海洋大陸・西太平洋で顕在化するMJO事例をその活動が活発な期間とともに同定し、MJOが特に顕著に観測される北半球冬季 (11月-4月) に対してMJOの顕在化頻度を定量化した上で、その経年変動を特徴付ける場を調査した。 その結果、MJOが顕在化しやすい年には、MJOよりも長い時間スケールでの対流活動がインド洋・西/中央太平洋 (海洋大陸) で有意に活発 (不活発) 傾向にあり、それに付随して背景場の東西循環は気候値よりも東西方向に伸展、南北循環は気候値が強化された傾向にあることを確認した。また、これらの場の実現には、成層圏準2年周期振動 (QBO) とエルニーニョ・南方振動 (ENSO) による協調的な強制が重要であることもわかった。具体的には、MJOの顕在化は、大振幅を除くエルニーニョ年であればQBO位相とは無関係にエルニーニョ傾向が強い時ほど、ENSO中立／ラニーニャ年であればENSOの振幅とは無関係にQBOに伴う上空東風が強い時ほど促進されることを見出し、これらが上記の背景場と無矛盾であることを示した。加えて、MJOが顕在化しづらい年には、MJOが顕在化しても西太平洋での水蒸気蓄積が阻害されるために持続期間が短くなることも判明し、この事実も背景場と整合的である。 さらに、本研究課題を遂行する上で、対流圏上層に捕捉された混合ロスビー重力波が背景場の東西循環との相互作用を通じて "湿潤過程を介さずに" MJOを顕在化させうることが新たに明らかとなった。その内容は投稿論文としてまとめられ、現在国際誌に投稿中である。

  5. 全球雲システム解像モデルを用いたＭＪＯの発現および東進の決定機構に関する研究

    高須賀 大輔

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 特別研究員奨励費

    Institution: 東京大学

    2017/04/26 - 2020/03/31

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    前年度の時点で、観測に基づく再解析データの統計解析などから、MJOの発生領域の決定には「海面水温 (SST) 分布によって部分的に強制されるMJOよりも長い時間スケールでの背景循環場」が重要であることが示唆されていた。これを踏まえ、本年度はこの知見の物理的理解および頑健性の検証に焦点を当て、引き続き再解析データを解析しつつ、全球雲システム解像モデルNICAMを用いた長期間の数値実験とその結果の解析を行った。 再解析データの解析から、1) MJOの発生領域によらず、その発生前には主に季節内の時間スケールでの東西循環に伴って水蒸気蓄積が促進しやすい場が形成されること、2) 東西循環が確立されやすい位置が背景循環場と連動して変調することがMJOの発生領域の決定に影響すること の2点が仮説として得られた。2) に関連して、インド洋でMJOが頻繁に発生する北半球冬季の平均的な状態に比べて、海大陸域 (西太平洋) でのMJO発生時には、SSTの経年変動成分が東部太平洋型のエルニーニョ (中央太平洋型のエルニーニョかつインド洋南東部での双極的構造) を伴う傾向にあったことを踏まえ、そのSST分布を模したものをNICAMの境界条件に設定し、15年間の季節固定実験 (北半球冬季) を複数実施した。その結果、いずれの実験でもMJOは自発的によく再現され、各実験間でのMJOの経度方向の発生確率分布の違いは、観測と整合的かつ統計的に有意であった。これは上述の2点の仮説の双方を支持するものであり、MJO発生領域の多様性の要因を初めて提唱するに至った。本内容は博士論文の一部としてまとめられ、国際誌への投稿論文として間もなく投稿できる段階にある。 前年度の主要な成果である「MJOと混合ロスビー重力波とのスケール間相互作用」については、その一般性を論じた論文を国際誌に投稿し、査読過程での改稿中である。