TERRAPUB Journal of Oceanography

Journal of Oceanography, Vol. 53 (No. 3), pp. 245-258, 1997

Time Series of Physical and Optical Parameters off Shimane, Japan, during Fall of 1993: First Observation by Moored Optical Buoy System for ADEOS Data Verification

J. Ishizaka1, I. Asanuma2, N. Ebuchi3, H. Fukushima4, H. Kawamura3, K. Kawasaki5, M. Kishino6, M. Kubota7, H. Masuko8, S. Matsumura9, S. Saitoh10, Y. Senga7, M. Shimanuki11, N. Tomii12 and M. Utashima13

1National Institute for Resources and Environment, 16-3 Onogawa, Tsukuba, Ibaraki 305, Japan
2Japan Marine Science and Technology Center, 2-15 Natsushima-machi, Yokosuka, Kanagawa 237, Japan
3Faculty of Science, Tohoku University, Aoba, Aramaki, Sendai, Miyagi 980, Japan
4School of High-Technology for Human Welfare, Tokai University, 317 Nishino, Numazu, Shizuoka 410-03, Japan
5National Research Institute of Fisheries Science, 2-12-4 Fukuura, Kanazawa, Yokohama, Kanagawa 236, Japan
6The Institute of Physical and Chemical Research, 2-1 Hirosawa, Wako, Saitama 351-01, Japan
7School of Marine Science and Technology, Tokai University, 3-20-1 Orido, Shimizu, Shizuoka 424, Japan
8Communication Research Laboratory, 893-1 Hirai, Kashima, Kashima, Ibaraki 314, Japan
9National Research Institute of Far Seas Fisheries, 5-7-1 Orido, Shimizu, Shizuoka 424, Japan
10Faculty of Fisheries, Hokkaido University, 3-1-1 Minato-machi, Hakodate, Hokkaido 041, Japan
11Japan Weather Association, 2-9-2 Kandanishiki, Chiyoda, Tokyo 101, Japan
12Remote Sensing Technology Center, 1401 Ohashi Numanoue, Hatoyama, Hiki, Saitama 350-03, Japan
13National Space Development Agency of Japan, 2-1-1 Sengen, Tsukuba, Ibaraki 305, Japan

(Received 26 June 1996; in revised form 18 October 1996; accepted 24 October 1996)

Abstract: A moored optical buoy system has been developed by the National Space Developmental Agency of Japan (NASDA) for verification of the ocean-observing sensors of the Advanced Earth Observation Satellite (ADEOS). The buoy was operated from August 25 to November 26, 1993, in the Japan Sea, off Shimane, Japan. Three-months time series of physical parameters indicate that the decrease of insolation and increase of wind velocity caused cooling of the sea surface and deepening of the mixed layer. The optical measurement systems of the buoy are still underdeveloped, and the experiment indicated several points that have to be improved. However, chlorophyll aconcentrations, estimated from upward radiance and downward irradiance at 1.8-m depth, are generally consistent with the chlorophyll fluorescence measured by a fluorometer of the buoy system. The time change of the chlorophyll aconcentration showed a gradual increase during October and a decrease in November. Simple calculations of enrichment of the mixed layer and critical depth theory could explain the fall bloom. Sea surface temperature showed a good correlation with coincident AVHRR/NOAA-12 MCSST data. Wind speed and direction and wave height also showed good correlations with ERS-1/AMI and TOPEX/POSEIDON data. The optical buoy system is useful for both verification of satellite data and understanding the time changes of physical and biological parameters.

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