Sato Katsufumi

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Sato
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Katsufumi
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  • Article
    Ocean observations in support of studies and forecasts of tropical and extratropical cyclones
    (Frontiers Media, 2019-07-29) Domingues, Ricardo ; Kuwano-Yoshida, Akira ; Chardon-Maldonado, Patricia ; Todd, Robert E. ; Halliwell, George R. ; Kim, Hyun-Sook ; Lin, I.-I. ; Sato, Katsufumi ; Narazaki, Tomoko ; Shay, Lynn Keith ; Miles, Travis ; Glenn, Scott ; Zhang, Jun A. ; Jayne, Steven R. ; Centurioni, Luca R. ; Le Hénaff, Matthieu ; Foltz, Gregory R. ; Bringas, Francis ; Ali, M. M. ; DiMarco, Steven F. ; Hosoda, Shigeki ; Fukuoka, Takuya ; LaCour, Benjamin ; Mehra, Avichal ; Sanabia, Elizabeth ; Gyakum, John R. ; Dong, Jili ; Knaff, John A. ; Goni, Gustavo J.
    Over the past decade, measurements from the climate-oriented ocean observing system have been key to advancing the understanding of extreme weather events that originate and intensify over the ocean, such as tropical cyclones (TCs) and extratropical bomb cyclones (ECs). In order to foster further advancements to predict and better understand these extreme weather events, a need for a dedicated observing system component specifically to support studies and forecasts of TCs and ECs has been identified, but such a system has not yet been implemented. New technologies, pilot networks, targeted deployments of instruments, and state-of-the art coupled numerical models have enabled advances in research and forecast capabilities and illustrate a potential framework for future development. Here, applications and key results made possible by the different ocean observing efforts in support of studies and forecasts of TCs and ECs, as well as recent advances in observing technologies and strategies are reviewed. Then a vision and specific recommendations for the next decade are discussed.
  • Article
    Stroke frequency, but not swimming speed, is related to body size in free-ranging seabirds, pinnipeds and cetaceans
    (Royal Society, 2006-12-05) Sato, Katsufumi ; Watanuki, Yutaka ; Takahashi, Akinori ; Miller, Patrick J. O. ; Tanaka, Hideji ; Kawabe, Ryo ; Ponganis, Paul J. ; Handrich, Yves ; Akamatsu, Tomonari ; Watanabe, Yuuki ; Mitani, Yoko ; Costa, Daniel P. ; Bost, Charles-Andre ; Aoki, Kagari ; Amano, Masao ; Trathan, Phil N. ; Shapiro, Ari D. ; Naito, Yasuhiko
    It is obvious, at least qualitatively, that small animals move their locomotory apparatus faster than large animals: small insects move their wings invisibly fast, while large birds flap their wings slowly. However, quantitative observations have been difficult to obtain from free-ranging swimming animals. We surveyed the swimming behaviour of animals ranging from 0.5kg seabirds to 30000kg sperm whales using animal-borne accelerometers. Dominant stroke cycle frequencies of swimming specialist seabirds and marine mammals were proportional to mass−0.29 (R2=0.99, n=17 groups), while propulsive swimming speeds of 1–2ms−1 were independent of body size. This scaling relationship, obtained from breath-hold divers expected to swim optimally to conserve oxygen, does not agree with recent theoretical predictions for optimal swimming. Seabirds that use their wings for both swimming and flying stroked at a lower frequency than other swimming specialists of the same size, suggesting a morphological trade-off with wing size and stroke frequency representing a compromise. In contrast, foot-propelled diving birds such as shags had similar stroke frequencies as other swimming specialists. These results suggest that muscle characteristics may constrain swimming during cruising travel, with convergence among diving specialists in the proportions and contraction rates of propulsive muscles.