A global eddying hindcast ocean simulation with OFES2
Hideharu Sasaki1, Shinichiro Kida2, Ryo Furue3, Hidenori Aiki4, Nobumasa Komori3, Yukio Masumoto5, Toru Miyama6, Masami Nonaka6, Yoshikazu Sasai7 and Bunmei Taguchi8, (1)JAMSTEC Japan Agency for Marine-Earth Science and Technology, Kanagawa, Japan, (2)Research Institute of Applied Mechanics, Kyushu University, Fukuoka, Japan, (3)JAMSTEC, Yokohama, Japan, (4)Nagoya University, Nagoya, Japan, (5)University of Tokyo, Bunkyo-ku, Japan, (6)JAMSTEC, Application Laboratory, Yokohama, Japan, (7)Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Research Institute for Global Change (RIGC), Yokohama, Japan, (8)University of Toyama, Faculty of Sustainable Design, Toyama, Japan
Abstract:
The Outputs from global eddying ocean simulations have been widely used to study various oceanic features whose spatiotemporal scales are broad: from mesoscales to large scales and from intraseasonal to decadal timescales. Long-term hindcast output from OFES (Ocean General Circulation Model for the Earth Simulator, Masumoto et al. 2004, Sasaki et al. 2008) has been accomplishing many research achievements following its release to the public. However, several issues with unrealistic properties exist in OFES. Therefore, we conducted a quasi-global eddying ocean simulation using “OFES2”, a new version of OFES.
We implemented a sea-ice model (Komori et al. 2005) and a tidal mixing scheme (St. Laurent et al. 2002) in OFES2, which is forced by a newly created surface atmospheric dataset called JRA55-do (Tsujino et al. 2018). We found several improvements in OFES2 over OFES: smaller biases in the global sea surface temperature and the sea surface salinity and water properties in the Indonesian and Arabian Seas. The time series of the Niño3.4 and Indian Ocean Dipole (IOD) indexes are somewhat better in OFES2 than in OFES. Unlike the previous version, OFES2 reproduces anomalous low sea surface temperatures in the upwelling region along Sumatra and Java during a positive IOD event because of the new atmospheric dataset. We believe that output from OFES2 will be useful in studying various oceanic phenomena with broad spatiotemporal scales.
