Yi Chia Hsin

Satellite views of the episodic terrestrial material transport to the southern Okinawa Trough driven by typhoon

Using satellite-derived water transparency (alias Secchi depth) images, we found clear signals of terrestrial material transport to the southern Okinawa Trough triggered by the Typhoon Morakot in August 2009. Three sources were identified: one is from the eastern coast of Taiwan, another is from the western coast of Taiwan, and the other is from the coast of mainland China. Carried by northward flows, typhoon-triggered terrestrial materials from both sides of Taiwans coasts were transported to the region northeast of Taiwan. Moreover, the terrestrial material from the coast of mainland China could cross the Taiwan Strait and be further transported to the region northeast of Taiwan. These typhoon-induced terrestrial materials off northeastern Taiwan could then be transported to the southern Okinawa Trough along the western edge of the Kuroshio. In addition to the particulate terrestrial material transported, nutrients might also be transported to the Kuroshio main stream. A significant phytoplankton bloom was observed along the Kuroshio path for about 300 km off northeast of Taiwan. Our results indicate that episodic cyclone-driven terrestrial material transport could be another source of mud in the southern Okinawa Trough.