A structure of the Kuroshio and its related upwelling on the East China Sea shelf slope

Abstract

The ADCP on an advanced towed fish with controllable main and tail wings, called DRAKE measured a detailed sectional structure of the Kuroshio flowing to the NE along the East China Sea shelf slope west of Okinawa. At the observation period, a countercurrent directed to the SW formed in near-bottom water on the shelf slope. The horizontal flow perpendicular to the stream axis of the Kuroshio constructed a convergence zone around the boundary between the Kuroshio and the countercurrent. An intensive upwelling with the maximum velocity of 2.8 cm s -1 was found to distribute on the shelf slope around the convergence zone. A dynamic cause of this intensive upwelling is discussed carefully.

Coastal upwelling on the far eastern Agulhas Bank associated with large meanders in the Agulhas Current

“…These eddies have an upward doming of isotherms in their centre with upwelling of water on the inshore side (Lutjeharms et al, 1989), similar to eddies in the Brazil Current (Compos et al, 1999;Castelão et al ., 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 1989), supplying more cold water for coastal upwelling, but do not appear to have played a measurable role near the coastline and in the bays of the far eastern Agulhas Bank during the Natal Pulses studied here. Other major western boundary currents, such as the Gulf Stream (Blanton et al, 1981;McClain et al, 1984;Savidge and Bane, 2001;Hyun and He, 2010) and the Kuroshio (Sugimoto et al, 1988;Ito et al, 1995) influence their coastal waters in a similar fashion. In the southern hemisphere, the Brazil Current and the East Australian Current are western boundary currents not unlike the Agulhas Current, although smaller in scale.…”

Latitudinal gradient in the distribution of intertidal barnacles of the Tetraclita species complex in Asian waters

“…Variation in barnacle density among locations is related to upwelling and variation in predation pressure. Strong upwelling in summer months has been reported to exist along the coastline of Izu Peninsula in Japan, the northeastern coastline of Taiwan and the Okinawa Island (Ishizaka et al 1992, Ito et al 1995, Lee & Chao 2003 (Fig. 2B).…”

“…Hydrography in Okinawa Island is mainly influenced by the Kuroshio Current from the south ( Fig. 1) (Ito et al 1995 Chiang et al 1997) (Fig. 1 (Liang et al 2003).…”

“…Upwelling can carry larvae out to the open ocean and thereby reduce recruitment density and frequency (Connolly et al 2001). Lower barnacle density on the coastline in Japan, Taiwan and Okinawa may result from the effect of upwelling (Ito et al 1995).…”

Why Are There Upwellings on the Northern Shelf of Taiwan under Northeasterly Winds?

“…Kuroshio meanders and/or frontal eddies may produce intense vertical motions at the shelf edge (Ito et al 1995;Yanagi et al 1998;Wu et al 2008, and references therein). Interaction of the strong current with topography also produces vertical motions (Hsueh et al 1992;Stern and Austin 1995), and so does cooling in combination with the joint effect of baroclinicity and relief (JEBAR) effects (Oey et al 2010).…”