Kuroshio

Fig. 1. Major oceanographic features 1. Canary Current, 2. Gulf Stream, 3. North Atlantic Current, 4. Sargasso Sea, 5. North Atlantic Gyre, 6. Labrador Current, 7. Loop Current, 8. North Pacific Gyre, 9. South Equatorial Current, 10. Benguela Current, 11. Humboldt Current, 12. Antilles Current, 13. Florida Current, 14. Brazil Current, 15. Kuroshio, 16. Antarctic West Wind Drift.

In the 1970s, the Sagami Chemical Research Center in Japan provided nutrient reference material for the Cooperative Study of the Kuroshio Current (the so-called CSK standards). These solutions were not prepared in seawater, which limits their general utility (see below), however they are still distributed and widely used as a common reference. French and British scientists have conducted some studies on nutrient reference material (Aminot and Keroul, 1991, 1996 Zhang et al., 1999) with limited success. 

Ocean. The former is estimated to have a surface area the size of Texas. The focusing effect of the Kuroshio Current on the density of plastics collected in plankton net tows is shown in Figure 28.35. In some locations, particle densities are greater than that of the local zooplankton. High concentrations have also been reported on the seabed near industrialized areas such as the Mediterranean and the North Seas. In 2000, the volume of litter estimated to be residing on the seabed of the North Sea was 600,000 m. ... 

Locations of stations sampied for piastic in 2000-2001. (a) Distribution and abundance (pieces/km ) of totai piastics in the Kuroshio Current area, (b) Sampies were coiiected by a surface tow using a neuston net (mouth opening 50 x 50cm side iength 3m mesh size 330. m). The numericaiiy dominant size class (62%) was 1-3 mm. Broken iine in (b) denotes the Kuroshio flow path during the study period. Source From Yamashita, R., and A. Tanimura (2007). Marine Pollution Bulletin 54, 464-488. 

Hama, T. 1992. Primary productivity and photosynthetic products around the Kuroshio warm-core ring. Deep Sea Research 39 279-293. 

Chen, Y.-L., Lu, H.-B., Shiah, F.-K., Gong, G. C., Liu, K.-K., andKanda,. (1999). New production and f-ratio on the continental shelf of the East China Sea Comparisons between nitrate inputs from the subsurface Kuroshio Current and the Changjiang River. Estuar. Coast. Shelf Sd. 48, 59—IS. 

Marumo, R., and Nagasawa, S. (1976). Seasonal variation of the standing crop of the pelagic blue-green alga, Trichodesmium in the Kuroshio water. Bull. Plankton Soc. Jpn. 23, 19—25. 

Gomez et al. (2005) observed the Chaetoceros-Richelia (note these authors use an alternative nomenclature) symbioses was restricted to the transition zones between the slope waters and the Kuroshio Current in the western Pacific Ocean. They proposed that their distribution was related to local mixing of the Kuroshio Current with the coastal waters, where Chaetoceros is a dominant member of the neritic phytoplankton population. 

Okinawa is Japan s southernmost prefecture, and consists of hundreds of islands known as the Ryukyus, in an island chain over 1000 km long, which extends southwest from Kyusyu (the southwestemmost of Japan s main four islands) to Taiwan. The warm waters of the Kuroshio Current have developed and sustained the coral reefs of Okinawa, which are among biologically the most diverse and the richest coral reefs in the world. 

The variable surface currents, which are typical of the Kuroshio area (Hsu et al. 1997, 1998 Mitnik et al. 1996), produced the displacement of a spill of different scales relative to its initial position. The high spatial resolution of SAR data allowed us to detect both the mesoscale and small-scale disturbances of a spill s shape, interpreting them as current-induced. 

Fig. 3. Map of bathymetry of the Kuroshio area east of southern Taiwan. Isobaths are shown for 2000 m, 1000 m and 200 m. Solid and dashed rectangles note the boundaries of the SAR images acquired on May 20, 1994 and December 29, 1997, respectively, and arrow AB shows the location of ship course...

The step-like features in area 15 can also be interpreted as current-induced. The arrows in Figure lb show the directions of surface currents in a small-scale elliptical eddy. These currents were responsible for the westward and eastward displacements of the spill band. This cyclonic eddy has a low radar contrast without distinct boundaries similar to the current shift lines 7 and 8. The different scaled eddy-like structures and also the eddy streets were earlier detected in ERS SAR images of the Kuroshio east of Taiwan (Hsu et al. 1997 1998, Mitnik et al. 1996, Mitnik and Hsu 1998). 

A light (with increased a° values) band 6 crosses the image from north to south. The band divides the warmer surface Kuroshio waters 7 from the colder waters 8 bordering the Taiwan coast. The difference in sea surface temperature between the Kuroshio and coastal waters is indicated by their brightness (the values of the NRCS). The higher NRCS values of the Kuroshio waters can be explained by the joint influence of two factors. The... 

Fig. 4. ERS-2 SAR image of the Kuroshio east of Taiwan acquired on December 29, 1997, at 02 29 UTC (copyright European Space Agency). Dashed square marks the boundaries of fragment shown in Figure 6...

The maximum displacement from line AB was observed in area C, east of Lutao (Figure lb). This displacement was most likely caused by an eastward component of the Kuroshio Current. The shape of the spill in area C is similar to the shape of feature 4. The interaction of the Kuroshio flow with Lutao and underwater rising around it were responsible for the appearance of both feature 4 and the eastward component of the current. The change in velocity of this component with distance manifested itself as the shape of departure y(x). The maximum displacement was found at a dis-... 

Fig. 5. Enlarged fragment (40 km x 50 km) of the ERS-1 SAR image obtained on May 20, 1994, at 14 20 UTC covering the area of the mesoscale cyclonic circulation east of Kuroshio boundary (copyright European Space Agency). The labels correspond to the labels in Figure lb...

The cyclonic eddy-like structures, similar to eddies 10 and 15 (Figure la) and 9-11 (Figure 4), are typical of the Kuroshio Current area east of Taiwan. They have been detected on many ERS-1/2 SAR images however, their position is variable. These eddies were observed due to their radar contrast against the background and/or the presence of definite structures (narrow spiral lines), resulting from the modulation of surface roughness by variable currents. Filamentary slicks were much less common here to favour their detection. Estimates of the current velocity for two eddies obtained by the analysis of the oil spill displacements were found to be 0.07-0.08 ms"1 and 0.3 ms"1. 

The spills of wastewater, and probably, the special-purpose man-made slicks, timed with satellite and airborne SAR observations, can be used to reveal and study the mesoscale and fine scale features of surface currents in this highly variable Kuroshio area during different seasons as well as in other dynamic oceanic areas. 

Ogura, N., 1972a. Dissolved organic matter in the sea, its production, utilization and decomposition. In K. Sugawara (Editor), The Kuroshio, II. Saigon Publ. Co., Tokyo, pp. 201—205. 

The Yellow Sea is affected by warm and saline oceanic currents and less saline coastal currents in a basin-wide scheme of a cyclonic gyre. In general, the former flow northward whilst the latter flow southward. On the east side of the Yellow Sea, the Kuroshio and Tsushima Warm Currents and the Yellow Sea... 

The East China Sea circulation is dominated by the northward flow of two loops of the Kuroshio Current (KC) the Taiwan Warm Water (TWW) in the west and the Yellow Sea Warm Water (YSWW) in the east. Both water masses are characterized by high salinity and warm water temperatures. In contrast, a southward flow in close to sea bottom water occurs from the flow of the Changjiang (CJCW) and Jiangsu Coastal Waters (JCW) along the Chinese coast, the Korean Coastal Waters (KCW) in the east, and the Yellow Sea Cold Waters (YSCW) in the north (Fig. 1.30, Lee and Chao, 2003). The coastal currents in particular appear as seasonally cold and brackish water masses. 

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