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HF radar and satellite observations of Oyashio 
intrusion process to the Funka Bay 
Sei-ichi Saitoh*, Kazuhiko Kasuga*, Hiroji Onishi*, Yutaka Isoda*, Hideo Miyake*, 
Akitsugu Nadai** and Satoshi Fujii** 
* Faculty of Fisheries 
Hokkaido University 
3-1-1, Minato-cho, Hakodate, Hokkaido 041, JAPAN 
E-mail: ssaitoh@salmon.fish.hokudai. ac.jp 
**Communication Research Laboratory 
Abstract 
An two-site HF ocean radar observation and satellite infrared observation were carried 
out around mouth of the Funka Bay, Hokkaido, Japan between 9 January and 9 March, 
1995. There were at least two evidences of the intrusion of Coastal Oyashio water to 
the Bay in the period of this study. The intrusion process of Coastal Oyashio water might 
not be continuously but intermittently. 
1. Introduction 
Observations of Kuroshio current by an HF ocean radar were made around the 
Tokara Strait(Akiyama et al., 1992). Recently, An two-site HF ocean radar observations 
were also made at the Tanegashima Strait for monitoring Kuroshio current(Ohno et al., 
1993). These studies demonstrated the usefulness of HF ocean radar as a tool to observe 
surface current system. 
An two-site HF ocean radar observation and satellite infrared observation were 
carried out around mouth of the Funka Bay, Hokkaido, Japan between 9 January and 9 
March, 1995, as one element of Hokkaido University suB-arctic Ecosystem dynamics 
and Climate(HUBEC) project. The objectives of this study are to understand how 
Coastal Oyashio Current (hereafter referred to COC) intrude to the Funka Bay. 
2. HF radar and Satellite observations 
2.1 HF radar observation and data analysis 
HF ocean radar developed at the Okinawa Radio Wave Observatory, Communication 
Research Laboratory. The radar is a pulsed-chirp (or FMICW) radar with a narrow beam 
antenna. The radar beam bearings can be scanned azimuthally over 90 degrees with 7.5