Mooring measurements off Shiretoko Peninsula, Hokkaido in 1997-1998
The region of the Okhotsk Sea off Hokkaido is known as a “confluence zone”of cold and fresh water from the northwestern Okhotsk, and warm and saline Soya Warm Water (SWW). These two water masses show strong seasonal variability in this region. In order to study this seasonal variability, a mooring w...
| Main Authors: | , , , , |
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.359.8997 http://www.pices.int/publications/scientific_reports/Report12/fukama_revf.pdf |
| Summary: | The region of the Okhotsk Sea off Hokkaido is known as a “confluence zone”of cold and fresh water from the northwestern Okhotsk, and warm and saline Soya Warm Water (SWW). These two water masses show strong seasonal variability in this region. In order to study this seasonal variability, a mooring was deployed at (44°32'N, 144°44'E, 1555 m deep) over the continental slope off Shiretoko Peninsula for a year in 1997-1998. The mooring consisted of two current meters at 247 and 1330 m, three thermistors at 165, 341, and 443 m, and a pressure sensor at 165 m. Average current speeds at the upper and lower current meters were 15.3 cm/s and 3.8 cm/s, respectively. This indicates that strong currents did not penetrate into the deeper ocean. Temperature time series clearly show the seasonal variability in the upper ocean. There were warm events up to 6°C at the upper thermistor from mid-December to mid-January. It is likely that this high temperature was caused by the advection of SWW into the region of the mooring. From late February, the temperature in the upper ocean decreased starting from the upper thermistor and approached the freezing point. The nearly freezing water is seen even at the middle thermistor (at 341 m) in early April. This indicates the development of a thick, surface-mixed layer in this season. |
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