Associate Professor Koutarou Takaya

Area and Subject Taught Meteorological dynamics
Research Theme(s) Geophysical Fluid Dynamics, Extreme climate, Climate variability
Academic Degrees Ph. D., University of Tokyo
Keywords for Research Field Meteorological dynamics
Office Phone Number +81-75-705-2934
e-mail E-mail

Research Overview

Our laboratory is interested in dynamics of climate variability. In particular, we are attempting to clarify dynamics of low-frequent variability of atmospheric circulations whose period is longer than one week or 10 days. Meandering of mid-latitude westerlies plays an important role of the low-frequent variability of the atmospheric circulations. For example, two typical circulation-anomaly patterns can be found in variability of the East Asian winter monsoon; the EU-like pattern and the WP-like pattern. The EU-like pattern is characterized by a wavy signature of the westerlies over the Eurasian continent and the North Atlantic, while the WP-like pattern is characterized by a meridional dipole of the pressure anomalies over the Northwestern Pacific. Thus, the variability of the East Asian winter monsoon is strongly linked to the atmospheric circulation anomalies with hemispheric scales. Our laboratory studies such a hemispheric circulation variability to clarify the dynamics of the climate variability.
Theoretical developments of geophysical fluid dynamics are also an important issue for our laboratory. Meandering midlatitude westerlies, which can affect climate variability, is associated with Rossby wave propagations. We are engaging theoretical studies of interactions Rossby waves and a basic state.

Notable Publications and Works in the Last Three Years

  • Aiki, H., K. Takaya, R.J. Greatbatch, 2015: A divergence-form wave-induced pressure inherent in the extension of the Eliassen-Palm theory to a three-dimensional framework for all waves at all latitudes. J.Atmos. Sci., in press.
  • Hisashi Nakamura, Kazuaki Nishii, Lin Wang, Yvan J. Orsolini, and Koutarou Takaya. Cold-air outbreaks over East Asia associated with blocking highs: Mechanisms and their interaction with the polar stratosphere. Chap. 4-21, “Dynamics and Predictability of Large-Scale High-Impact Weather and Climate Events” edited by Jianping Li, Richard Swinbank, Hans Volkert and Richard Grotjahn, ICDM (気象力学国際委員会)books. 2015.(著書)。
  • Morioka, Y., K.Takaya, S. K. Behera, and Y. Masumoto, 2015: Local SST impacts on the summertime Mascarene High variability. J. Climate, 28, 678-694. doi: http://dx.doi.org/10.1175/JCLI-D-14-00133.1
  • Shoji, T., Y. Kanno, T. Iwasaki, and K. Takaya, 2014: An isentropic analysis of the temporal evolution of East Asian cold air outbreaks. J. Climate, 27, 9337-9348. doi: http://dx.doi.org/10.1175/JCLI-D-14-00307.1
  • Iwasaki, T., T. Shoji, Y. Kanno, M. Sawada, M. Ujiie, and K. Takaya, 2014: Isentropic analysis of polar cold airmass streams in the northern hemispheric winter. J. Atmos. Sci., 71, 2230-2243, DOI: 10.1175/ JAS-D-13-058.1.
  • Takaya, K. and H. Nakamura: Interannual variability of the East Asian winter monsoon and related modulations of the planetary waves. J. Climate, 26, 2013, 9445-9461.
  • Inoue, J., M. E. Hori and K. Takaya: The role of Barents Sea ice in the wintertime cyclone track and emergence of a warm-Arctic and cold-Siberian anomaly. J. Climate. 25, 2012, 2561-2568, DOI: 10.1175/JCLI-D-11-00449.1
  • Taguchi, B., H. Nakamura, M. Nonaka, N. Komori, A. Kuwano-Yoshida, K. Takaya and A. Goto: Seasonal evolutions of atmospheric response to decadal SST anomalies in the North Pacific subarctic frontal zone: Observations and a coupled model simulation. J. Climate, 25, 2012, 111-139.