for Predicting Oceanic Variability Near Japan
Dr. Toshio Yamagata
(Professor of Tokyo University), Program Director, and Mr. Yasumasa Miyazawa's
research group in the Climate Variations Research Program of the Frontier Research
System for Global Change (a joint project of NASDA and JAMSTEC) have commenced
experiments using high-resolution ocean general circulation models (OGCMs) to
predict oceanic variability with particular emphasis on variations in the Kuroshio
path near Japan.(reference)
has developed a system for predicting the Kuroshio variability and the mesoscale
eddy behavior that greatly influence the Japan coastal ocean. The system uses
a high-resolution OGCM that well simulates the Kuroshio meander and the mesoscale
eddy activity and sea surface height anomaly data obtained from satellite observations.
The experiments that simulate the Kuroshio path in the past, and then predict
"future" state from that state using the OGCM (hindcast experiments:
see note), revealed that, at present, the prediction of the Kuroshio variability
is feasible for up to two months in advance.
In addition to constructing
a system for experimental prediction of the oceanic variability at regular intervals,
and predicting and verifying the Kuroshio path variations, this research group
also intends to improve the models with the aim of practical application of systems
that incorporate even more detailed predictions of coastal oceanographic conditions.
hindcast experiment is a simulation, referring to an experiment that predicts
future conditions by simulating them from a state in the past.
routine predictions of oceanic variation ("ocean weather reports"),
combined with the prediction results from in-situ verification, are expected to
considerably contribute to the improvement of atmosphere-ocean models that predict
longer-term climate change. From this practical perspective of computational science,
detailed elucidation and prediction of oceanographic variability in the sea near
Japan is extremely important for Japan to appropriately manage and to sustainedly
develop the Exclusive Economic Zones (EEZ).
A high-resolution OGCM was developed with a horizontal
resolution of about 10 km and 35 levels that resolve the detailed sea bottom topography.
This OGCM has been successfully simulated for the first time in the world the
variability of sea surface height caused by variations in the Kuroshio path and
mesoscale eddies in the sea near Japan (fig. 1). Given
the initial conditions (Kuroshio path and the location of eddies nearby) estimated
using data from the satellite (NASA: TOPEX/POSEIDON) that routinely observes sea
surface height variation, the OGCM simulated the variability of the Kuroshio path
over the subsequent two months (fig. 2a, fig
Institute of Earth Sciences (3173-25 Showa-machi, Kanazawa-ku, Yokohama City,
Kanagawa Prefecture 236-0001, Japan) will conduct separate simulation demonstrations
at the request of the press. Please direct press inquiries to the FRSGC Joint
System for Global Change, Joint Promotion Office
Contact: Mr. Kawasaki
+81 (0)45-778-5680 (direct)
Public Relations Office
Tel: +81 (0)3-3438-6107, -6108, or -6109
Public Relations Office, General Affairs Department
Tel: +81 (0)***********