Current dynamics Current mooring observations in the area of the South Kuril Islands

• Main Authors: Georgy Shevchenko, Gennady Kantakov, Valery Chastikov
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Okhotsk; Pacific; okhotsk sea; Sakhalin
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.360.1540; http://www.pices.int/publications/scientific_reports/Report36/128-133-Current-mooring-observations.pdf

Our knowledge of dynamic processes in the area adjacent to the South Kuril Islands is very limited because of a lack of current mooring observations. The information related to currents in this region was obtained from satellite-tracked drifters (Rabinovich and Thomson, 2001; Ohshima et al., 2005). To investigate currents in this region, the Sakhalin Research Institute of Fisheries and Oceanography installed two moorings in the shelf waters of Urup and Kunashir islands in 2003. Experimental studies of dynamic processes were conducted from 2004–2005 in the areas adjacent to Kunashir Island. Diurnal tidal currents strongly dominate on the northern shelf of Urup Island, especially the east-directed component. Tidal currents are almost rectilinear and very steady. Stable east-directed residual currents with an average velocity of 10–12 cm/s were found from April until September which means that there was an outflow of Okhotsk Sea water to the Pacific Ocean through Urup Strait during this period. We found significant amplification of the current in October and November, with the current direction becoming northeast. Autumn typically is a time of atmospheric fields changing to the so-called winter monsoon, with its strong northwesterly winds; however, we did not find this changing in the fall of 2003, from reanalysis data. Another cause of current amplification probably followed, besides the baroclinic effect. However, the noted phenomena are still unclear because there were no salinity sensors at the moorings. A temperature maximum (8–9°C) was found in the second half of October (about two times greater than in August). A similar current amplification was observed near Ekaterina Strait in September–October. We also found tides weakening at this time.