Takahiro Toyoda

[Japanese]
Subject Description
Job title Senior Researcher
Section The fourth Laboratory/Department of Atmosphere, Ocean, and Earth System Modeling Research
E-mail rotoyodatakahir
Other web page http://researchmap.jp/page_ttoyoda
Field of expertise/interest physical oceanography, data assimilation, ocean modeling, sea ice, surface mixed layer, mode water
Degree PhD (Science)
Publications Original articles (lead author)
  • Toyoda, T., K. Sakamoro, T. Toyota, H. Tsujino, L. S. Urakawa, Y. Kawakami, A. Yamagami, K. K. Komatsu, G. Yamanaka, T. Tanikawa, R. Shimada, and H. Nakano: Improvements of sea ice thermodynamics with variable sea ice salinity and melt pond parameterizations in an OGCM, Ocean Modelling, accepted.
  • Toyoda, T., L. S. Urakawa, H. Aiki, H. Nakano, E. Shindo, H. Yoshimura, Y. Kawakami, A. Yamagami, Y. Ushijima, Y. Harada, C. Kobayashi, H. Tomita, T. Tozuka, and G. Yamanaka (2023): Effective generation mechanisms of tropical instability waves as represented by high-resolution coupled atmosphere-ocean prediction experiments, Scientific Reports, 13, 14742.
  • Toyoda, T., Y. Kitamura, R. Okada, K. Matsumura, K. K. Komatsu, K. Sakamoto, L. S. Urakawa, and H. Nakano (2022): Sea ice variability along the Okhotsk coast of Hokkaido based on long-term JMA meteorological observatory data, Okhotsk Sea and Polar Oceans Research, 6, 27-35.
  • Toyoda, T., K. Sakamoto, N. Usui, N. Hirose, K. Tanaka, T. Katsumata, D. Takahashi, M. Niki, K. Kutsuwada, T. Miyama, H. Nakano, L. S. Urakawa, K. K. Komatsu, Y. Kawakami, and G. Yamanaka (2021): Surface-layer circulations in Suruga Bay induced by intrusions of Kuroshio branch water, Frontiers in Marine Science, 8, 721500.
  • Toyoda, T., N. Kimura, L. S. Urakawa, H. Tsujino, H. Nakano, K. Sakamoto, G. Yamanaka, K. K. Komatsu, Y. Matsumura, and Y. Kawaguchi (2021): Improved representation of Arctic sea ice velocity field in ocean–sea ice models based on satellite observations, Climate Dynamics, 57, 2863-2887.
  • Toyoda, T., H. Nakano, H. Aiki, T. Ogata, Y. Fukutomi, Y. Kanno, L. S. Urakawa, K. Sakamoto, G. Yamanaka, and M. Nagura (2021): Energy flow diagnosis of ENSO from an ocean reanalysis, Journal of Climate, 34, 4023-4042.
  • Toyoda, T., T. Aoki, M. Niwano, T. Tanikawa, L. S. Urakawa, H. Tsujino, H. Nakano, K. Sakamoto, N. Hirose, and G. Yamanaka (2020): Impact of observation-based snow albedo parameterization on global ocean simulation results, Polar Science, 20, 100521.
  • Toyoda, T., K. Iwamoto, L. S. Urakawa, H. Tsujino, H. Nakano, K. Sakamoto, G. Yamanaka, Y. Komuro, S. Nishino, and J. Ukita (2019): Incorporation of satellite-derived thin-ice data into a global OGCM simulation, Climate Dynamics, 53, 7113-7130.
  • Toyoda, T., et al. (2019): Effects of inclusion of adjoint sea ice rheology on backward sensitivity evolution using an adjoint ocean-sea ice model, Monthly Weather Review, 147, 2145-2162.
  • Toyoda, T., and S. Okamoto (2017): Physical forcing of late summer chlorophyll a blooms in the oligotrophic eastern North Pacific, Journal of Geophysical Research: Oceans, 122, 1849-1861.
  • Toyoda, T., et al. (2017): Interannual‑decadal variability of wintertime mixed layer depths in the North Pacific detected by an ensemble of ocean syntheses, Climate Dynamics, 49, 891-907.
  • Toyoda, T., et al. (2017): Intercomparison and validation of the mixed layer depth fields of global ocean syntheses, Climate Dynamics, 49, 753-773.
  • Toyoda, T., et al. (2016): Data assimilation of sea ice concentration into a global ocean–sea ice model with corrections for atmospheric forcing and ocean temperature fields, Journal of Oceanography, 72, 235-262.
  • Toyoda, T., et al. (2015): An improved simulation of the deep Pacific Ocean using optimally estimated vertical diffusivity based on the Green’s function method, Geophysical Research Letters, 42, 9916-9924.
  • Toyoda, T., et al. (2015): Improvements to a global ocean data assimilation system through the incorporation of Aquarius surface salinity data, Quarterly Journal of the Royal Meteorological Society, 141, 2750–2759.
  • Toyoda, T., T. Awaji, S. Masuda, N. Sugiura, H. Igarashi, Y. Sasaki, Y. Hiyoshi, Y. Ishikawa, S.-I. Saito, S. Yoon, T. In, and M. J. Kishi (2013): Improved state estimations of lower trophic ecosystems in the global ocean based on a Green's function approach, Progress in Oceanography, 119, 90-107.
  • Toyoda, T., Y. Fujii, T. Yasuda, N. Usui, T. Iwao, T. Kuragano, and M. Kamachi (2013): Improved analysis of seasonal-interannual fields using a global ocean data assimilation system, Theoretical and Applied Mechanics Japan, 61, 31-48.
  • Toyoda, T., et al. (2011): Impact of the assimilation of sea ice concentration data on an atmospheric-ocean-sea ice coupled simulation of the Arctic Ocean climate, Scientific Online Letters on the Atmosphere, 7, 037-040.
  • Toyoda, T., T. Awaji, S. Masuda, N. Sugiura, H. Igarashi, T. Mochizuki, and Y. Ishikawa (2011): Interannual variability of North Pacific eastern subtropical mode water formation in the 1990s derived from a 4-dimensional variational ocean data assimilation experiment, Dynamics of Atmospheres and Oceans, 51, 1-25.
  • Toyoda, T., S. Masuda, N. Sugiura, T. Mochizuki, H. Igarashi, M. Kamachi, Y. Ishikawa, and T. Awaji (2009): A possible role for unstable coupled waves affected by resonance between Kelvin waves and seasonal warming in the development of the strong 1997–1998 El Nino, Deep Sea Research I, 56, 495-512.
  • Toyoda, T., T. Awaji, Y. Ishikawa, and T. Nakamura (2004): Preconditioning of winter mixed layer in the formation of North Pacific eastern subtropical mode water, Geophysical Research Letters, 31, L17206.
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Collavorative works
  • Yagamami, A., M. Kajino, T. Maki, and T. Toyoda (2023): Spatiotemporal variations in summertime Arctic aerosol optical depth caused by synoptic-scale atmospheric circulation in three reanalyses. Journal of Geophysical Research, 128, e2022JD038007.
  • Sakamoto, K., H. Nakano, T. Toyoda, L. S. Urakawa, and H. Tsujino (2023): Average coastal residence time distribution estimated by a 2-km resolution Japanese coastal model. Journal of Oceanography, accepted.
  • Tozuka, T., T. Toyoda, and M. F. Cronin (2023): Role of mixed layer depth in Kuroshio Extension decadal variability. Geophysical Research Letters, e2022GL101846.
  • Komatsu, K. Kensuke, Y. Takaya, T. Toyoda, and H. Hasumi (2023): A submonthly scale causal relation between snow cover and surface air temperature over the autumnal Eurasian continent, Journal of Climate, 36, 4863-4877.
  • Nakano, H., L. S. Urakawa, K. Sakamoto, T. Toyoda, Y. Kawakami, and G. Yamanaka (2023): Long-term sea-level variability along the coast of Japan during the 20th century revealed by a 1/10° OGCM, Journal of Oceanography, 79, 123-143.
  • Kawakami, Y., H. Nakano, L. S. Urakawa, T. Toyoda, K. Sakamoto, G. Yamanaka, and S. Sugimoto (2023): Cold- versus warm-season-forced variability of the Kuroshio and North Pacific subtropical mode water, Scientific Reports, 13, 256.
  • Nomura, D., et al. (2022): Atmosphere-sea ice-ocean interaction study in Saroma-ko Lagoon, Hokkaido, Japan 2021, Bulletin of Glaciological Research, 40, 1-17.
  • Komatsu, K. K., Y. Takaya, T. Toyoda, and H. Hasumi (2022): Exploring response of Eurasian temperature to Barents-Kara sea ice and Warm-Arctic Cold-Eurasia pattern: analysis of multi-model seasonal predictions, Geophisical Research Letters, 49, e2021GL097203.
  • Kawakami, Y., et al. (2022): Interactions between ocean and successive typhoons in the Kuroshio region in 2018 in atmosphere-ocean coupled simulations, Journal of Geophysical Research: Oceans, 127, e2021JC018203.
  • Keen, A., et al. (2021): An inter-comparison of the mass budget of the Arctic sea ice in CMIP6 models, The Cryoshpere, 15, 951-982.
  • Yamanaka, G., H. Nakano, K. Sakamoto, T. Toyda, S. Urakawa, S. Nishikawa, T. Wakamatsu, H. Tsujino, and Y. Ishikawa (2021): Projected climate change in the western North Pacific at the end of the 21st century from ensemble simulations with a high-resolution regional ocean model, Journal of Oceanography, 77, 539-560.
  • Aiki, N., Y. Fukutomi, Y. Kanno, T. Ogata, T. Toyoda, and H. Nakano (2021): The energy flux of three-dimensional waves in the atmosphere: Exact expression for a basic model diagnosis with no equatorial gap, Journal of the Atmospheric Sciences, 78, 3745-3758.
  • Nakano, H., et al. (2021): Effects of eddies on the subduction and movement of water masses that reach the 137◦E section using Lagrangian particles in an eddy-resolving OGCM, Jounal of Oceanography, 77, 283-305.
  • Kosugi, N., N. Hirose, T. Toyoda, and M. Ishii (2021): Rapid freshening of Japan Sea Intermediate Water in the 2010s, Jounal of Oceanography, 77, 269-281.
  • Urakawa, L. S., et al. (2020): The sensitivity of a depth-coordinate model to diapycnal mixing induced by practical implementations of the isopycnal tracer diffusion scheme, Ocean Modelling, 154, 101693.
  • Mugo, R., S.-I. Saitoh, H. Igarashi, T. Toyoda, S. Masuda, T. Awaji, and Y. Ishikawa (2020): Identification of skipjack tuna (Katsuwonus pelamis) pelagic hotspots applying a satellite remote sensing-driven analysis of ecological niche factors: A short-term run. PLoS ONE, 15, e0237742.
  • Notz, D., et al. (2020): Arctic sea ice in CMIP6, Geophysical Research Letters, 47, e2019GL086749.
  • Jackson, L. C., et al. (2019): The mean state and variability of the North Atlantic circulation: A perspective from ocean reanalyses, Journal of Geophysical Research: Oceans, 124, 9141-9170.
  • Hirose, N., N. Usui, K. Sakamoto, H. Tsujino, G. Yamanaka, H. Nakano, S. Urakawa, T. Toyoda, Y. Fujii, and N. Kohno (2019): Development of a new operational system for monitoring and forecasting coastal and open-ocean states around Japan, Ocean Dynamics, 69, 1333-1357.
  • Sakamoto, K., H. Tsujino, H. Nakano, S. Urakawa, T. Toyoda, N. Hirose, N. Usui, and G. Yamanaka (2019): Development of a 2-km resolution ocean model covering the coastal seas around Japan for operational application, Ocean Dynamics, 69, 1181-1202.
  • Uotila, P., et al. (2019): An assessment of ten ocean reanalyses in the polar regions, Climate Dynamics, 52, 1613-1650.
  • Nakano, H., H. Tsujino, K. Sakamoto, S. Urakawa, T. Toyoda, and G. Yamanaka (2018): Identification of the fronts from the Kuroshio Extension to the Subarctic Current using absolute dynamic topographies in the satellite altimetry products, Journal of Oceanography, 74, 393-420.
  • Takaya, Y., et al. (2017): Japan Meteorological Agency/Meteorological Research Institute‑Coupled Prediction System version 2 (JMA/MRI‑CPS2): atmosphere–land–ocean–sea ice coupled prediction system for operational seasonal forecasting, Climate Dynamics, 50, 751-765.
  • Usui, N., et al. (2017): Four-dimensional variational ocean reanalysis: a 30-year high-resolution dataset in the western North Pacific (FORA-WNP30), Jounal of Oceanography, 73, 205-233.
  • Igarasi, H., et al. (2017): Possible link between interannual variation of neon flying squid (Ommastrephes bartramii) abundance in the North Pacific and the climate phase shift in 1998/1999, Progress in Oceanography, 150, 20-34.
  • Chevallier, M., et al. (2017): Erratum to: Intercomparison of the Arctic sea ice cover in global ocean–sea ice reanalyses from the ORA-IP project, Climate Dynamics, 49, 1137-1138.
  • Chevallier, M., et al. (2017): Intercomparison of the Arctic sea ice cover in global ocean–sea ice reanalyses from the ORA-IP project, Climate Dynamics, 49, 1107-1136.
  • Shi, L., et al. (2017): An assessment of upper ocean salinity content from the Ocean Reanalyses Inter-comparison Project (ORA-IP), Climate Dynamics, 49, 1009-1029.
  • Valdivieso, M., et al. (2017): An assessment of air–sea heat fluxes from ocean and coupled reanalyses, Climate Dynamics, 49, 983-1008.
  • Fujii, Y., et al. (2017): Enhancement of the southward return flow of the Atlantic Meridional Overturning Circulation by data assimilation and its influence in an assimilative ocean simulation forced by CORE‑II atmospheric forcing, Climate Dynamics, 49, 869-889.
  • Palmer, M. D., et al. (2017): Ocean heat content variability and change in an ensemble of ocean reanalyses, Climate Dynamics, 49, 909-930.
  • Storto, A., et al. (2017): Steric sea level variability (1993–2010) in an ensemble of ocean reanalyses and objective analyses, Climate Dynamics, 49, 709-729.
  • Noh, Y., H. Ok, E. Lee, T. Toyoda, and N. Hirose (2016): Parameterization of Langmuir circulation in the ocean mixed layer model using LES and its application to the OGCM, Journal of Physical Oceanography, 46, 57-78.
  • Doi, T., et al. (2015): Multidecadal change in the dissolved inorganic carbon in a long-term ocean state estimation, Journal of Advances in Modeling Earth Systems, 7, 1885-1900.
  • Nishikawa, H., et al. (2015): Wind-induced stock variation of the neon flying squid (Ommastrephes bartramii) winter–spring cohort in the subtropical North Pacific Ocean, Fisheries Oceanography, 24, 229-241.
  • Balmaseda, M. A., et al. (2015): Ocean Reanalyses Intercomparison Project (ORA-IP), Journal of Operational Oceanography, 8, s80-s97.
  • Kuragano, T., et al. (2014): Seasonal barotropic sea surface height fluctuation in relation to regional ocean mass variation, Journal of Oceanography, 70, 45-62.
  • Sakamoto, T. T., et al. (2012): MIROC4h—A new high-resolution atmosphere-ocean coupled general circulation model, Journal of the Meteorological Society of Japan, 90, 325-359.
  • Kouketsu, S., et al. (2011): Deep ocean heat-content changes estimated from observation and reanalysis data and their influence on sea level change, Journal of Geophysical Research, 116, C03012.
  • Masuda, S., et al. (2010): Simulated rapid warming of abyssal North Pacific waters, Science, 329, 319.
  • Mochizuki, T., et al. (2010): Pacific decadal oscillation hindcasts relevant to near-term climate prediction, Preceedings of the National Academy of Sciences of the United States of America, 107, 1833-1837.
  • Igarashi, H., T. Awaji, T. Toyoda, S. Masuda, N. Sugiura, Y. Sasaki, Y. Hiyoshi, M. Sakai, T. Ichii, and Y. Ishikawa (2010): An optimal synthesis of observations and models by data assimilation: applications to climate analysis and fishery assessment, IEEE eartthzine.
  • Masuda, S., et al. (2009): Temporal evolution of the equatorial thermocline associated with the 1991–2006 ENSO, Journal of Geophysical Research, 114, C03015.
  • Sugiura, N., T. Awaji, S. Masuda, T. Toyoda, H. Igarashi, Y. Ishikawa, M. Ishii, and M. Kimoto (2009): Potential for decadal predictability in the North Pacific region, Geophysical Research Letters, 36, L20701.
  • Mochizuki, T., N. Sugiura, T. Awaji, and T. Toyoda (2009): Seasonal climate modeling over the Indian Ocean by employing a 4D-VAR coupled data assimilation approach, Journal of Geophysical Research, 114, C11003.
  • Ishikawa, Y., T. Awaji, T. Toyoda, T. In, K. Nishina, T. Nakamura, S. Shima, and S. Masuda (2009): High-resolution synthetic monitoring by a 4-dimensional variational data assimilation system in the northwestern North Pacific, Jounal of Oceanography, 78, 237-248.
  • Sugiura, N., et al. (2008): Development of a four-dimensional variational coupled data assimilation system for enhanced analysis and prediction of seasonal to interannual climate variations, Journal of Geophysical Research, 113, C10017.
  • Masuda, S., et al. (2006): Interannual variability of temperature inversions in the subarctic North Pacific, Geophysical Research Letters, 33, L24610.
  • Nakamura, T., T. Toyoda, Y. Ishikawa, and T. Awaji (2006): Effects of tidal mixing at the Kuril Straits on North Pacific ventilation: Adjustment of the intermediate layer revealed from numerical experiments, Journal of Geophysical Research, 111, C04003.
  • Nakamura, T., T. Toyoda, Y. Ishikawa, and T. Awaji (2006): Enhanced ventilation in the Okhotsk Sea through tidal mixing at the Kuril Straits, Deep-Sea Research I, 53, 425-448.
  • Nakamura, T., T. Toyoda, Y. Ishikawa, and T. Awaji (2004): Tidal mixing in the Kuril Straits and Its Impact on Ventilation in the North Pacific Ocean, Jounal of Oceanography, 60, 411-423.
  • Ishikawa, Y., T. Awaji, N. Komori, and T. Toyoda (2004): Application of sensitivity analysis using an adjoint model for short-range forecasts of the Kuroshio path south of Japan, Journal of Oceanography, 60, 293-301.
  • Awaji, T., S. Masuda, Y. Ishikawa, N. Sugiura, T. Toyoda, and T. Nakamura (2003): State estimation of the North Pacific ocean by a four-dimensional variational data assimilation experiment, Journal of Oceanography, 59, 931-943.
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Projects