OFES

Last updated: May 28, 2004

Eddy-Resolving Simulation of the World Ocean

A continuing effort of pushing the frontier of the global eddy-resolving simulation: one of the center's core projects cooperatively designed by oceanographic research teams in Frontier Research System for Global Change.

Objective

The world ocean plays an important role in climate variability and its reliable modeling with less parameterization is a growing concern for not only the oceanographic but also climate research community as a whole. Accumulated knowledge through modeling studies shows that high-resolution simulations are quite informative and hence useful for data-sparse climate researches since their outputs are expected to provide comprehensive three dimensional datasets that aid us in interpreting the extensive observations made during the last decade [Smith et al., 2000].

Recent numerical studies suggest that a grid spacing on the order of 0.1° is a threshold for a good representation of the western boundary currents and of the mesoscale eddy kinetic energy [Chassignet et al., 2002]. The usefulness of such high-resolution simulations are demonstrated here focusing on the enhanced regional features of surface circulations manifested in our eddy-resolving global ocean simulation carried out on the Earth Simulator.

OGCM

Based on MOM3, we have developed an OGCM code (OFES: OGCM for the Earth Simulator) optimized for massively-parallel computations on the ES.

Overview of the selected outputs

Sea surface height variability

Figure 1. The rms variability of sea surface height. (Left) Observation from satellite altimetry. (Right) Simulation result.
Tropical instability waves

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Figure 2. A snapshot of sea surface temperature in the Tropical Pacific.
Sea surface temperature field and the western boundary currents reflected in it

Figure 3. (a) A snapshot of sea surface temperature in the Kuroshio region and (b) that in the Gulf Stream region.

Thermocline structure in the equatorial Pacific ocean


Figure 4. (Left) Mean zonal geostrophic flow [cm s^-1], temperature [°C], and salinity [psu] between Hawaii and Tahiti and from 0–400 m, for the period April 1979–March 1980. Adapted from Wyrtki and Kilonsky [1984]. (Right) Annual mean fields calculated from the model results along 155°W in the year 50.

Publications related to our new simulations

Masumoto Y., H. Sasaki, T. Kagimoto, N. Komori, A. Ishida, Y. Sasai, T.Miyama, T. Motoi, H. Mitsudera, K. Takahashi, H. Sakuma, and T.Yamagata, 2004: A Fifty-Year Eddy-Resolving Simulation of the World
Ocean - Preliminary Outcomes of OFES (OGCM for the Earth Simulator)-, J.Earth Sim., 1, 35-56.
Sakuma, H., H. Sasaki, K. Takahashi, T. Kagimoto, T. Yamagata, and T. Sato, 2003: Global Eddy-resolving simulation by the Earth Simulator: Brief report on the first run. Recent Advances in Marine Science and Technology 2002..
Sakuma, H., H. Sasaki, K. Takahashi, Y. Tsuda, M. Kanazawa, S. Kitawaki, T. Kagimoto, and T. Sato, 2003: Accomplishment of fifty-years-long global eddy-resolving simulation by the Earth Simulator. NEC Research & Development, 44 (1), 104–108.
Takahashi, K., Y. Tsuda, M. Kanazawa, S. Kitawaki, H. Sasaki, and T. Sato, 2003: Parallel architecture and its performance of Oceanic Global Circulation Model based on MOM3 to be run on the Earth Simulator. in Parallel Computational Fluid Dynamics — New Frontiers and Multi-Disciplinary Applications, K. Matsuno et al. (Editors), pp. 101–108, Elsevier.

Presentations

Kagimoto, T., H. Sasaki, Y. Masumoto, A. Ishida, N. Komori, K. Takahashi, Y. Sasai, Y. Yamanaka, H. Sakuma, and T. Yamagata, 2002: Eddy-resolving simulation in the world ocean. Part III: Comparison with the WOCE hydrographic observations. JOS 2002 Fall Meeting, Sapporo, Hokkaido, Japan, October 2002.
Komori, N., H. Sasaki, K. Takahashi, T. Kagimoto, Y. Masumoto, A. Ishida, Y. Sasai, T. Motoi, S. Masuda, Y. Yamanaka, K. Komine, R. Jung, H. Sakuma, and T. Sato, 2002: Eddy-resolving simulation in the world ocean. Part II: Regional features of surface circulations. JOS 2002 Fall Meeting, Sapporo, Hokkaido, Japan, October 2002.
Sasaki, H., T. Kagimoto, N. Komori, K. Takahashi, Y. Masumoto, Y. Tsuda, M. Kanazawa, A. Ishida, Y. Sasai, K. Komine, R. Jung, Y. Yamanaka, S. Masuda, T. Motoi, M. Kitawaki, H. Sakuma, T. Yamagata, and T. Sato, 2002: Eddy-resolving simulation of the world ocean circulation —Fifty years integration on the Earth Simulator—. WOCE Final Conference, San Antonio, Texas, U.S.A., November 2002.
Sasaki, H., K. Takahashi, N. Komori, T. Kagimoto, Y. Masumoto, Y. Tsuda, M. Kanazawa, A. Ishida, Y. Sasai, K. Komine, R. Jung, Y. Yamanaka, S. Masuda, T. Motoi, M. Kitawaki, H. Sakuma, and T. Sato, 2002: Eddy-resolving simulation in the world ocean. Part I: Accomplishment of fifty-year time-integration on the Earth Simulator. JOS 2002 Fall Meeting, Sapporo, Hokkaido, Japan, October 2002.
Takahashi, K., M. Kanazawa, Y. Tsuda, M. Kitawaki, H. Sasaki, T. Kagimoto, Y. Masumoto, H. Sakuma, and T. Yamagata: Computational performance and preliminary physical validations of eddy-resolving simulation on the Earth Simulator. AGU 2002 Spring Meeting, May 2002.