| Tropical cyclones (also known as hurricanes or typhoons) may have devastating effects on human lives, when passing over land. One hand, over the ocean the importance of air-sea interaction in affecting tropical cyclones intensity has been previously documented. On the other hand, sea surface cooling, vertical mixing and Ekman pumping occurred after tropical cyclones passage. Besides, they can strongly enhance another form of life-ocean primary (phytoplankton) production over the ocean. In this paper, the biophysical responses of the upper ocean to some tropical cyclones in the Northwest Pacific were studied by using multiplatform satellite remote sensing data, Argo profiles data and the cruise data.First, the biophysical responses of the upper ocean to typhoon TINGTING in 2004 were analyzed. Along TINGTING's passages, satellite instruments detected the surface chlorophyll a concentration increase (0.08~0.15mg/m?3) and sea surface cooling (4~5℃) in the wake. The wind fields intensified the oceanic cyclonic circulation, sea upwelling, surface cooling, and deepened the mixed layer (20–35m). The mixing and upwelling injected subsurface phytoplankton and nutrients into the surface layer, resulting in two-week-long phytoplankton blooms. The surface cooling and phytoplankton blooms occurred mainly in the pre-existing cyclonic circulation area, but few in the pre-existing anticyclonic circulation area. This work provide a convincing evidence that negative sea surface features play important roles in biophysical responses of the upper ocean to typhoon.Second, the formation of the Kuroshio large meander in summer 2004 was investigated. The authors validated the point that cyclonic eddies contributed to the large meander. Besides, the impacts of typhoons on Kuroshio meanders were also studied. From 29July to 4 August, the typhoons stirred the ocean and upwelled the deep water, which enhanced the existed cyclonic eddy, and immediately made a drastic meander of the Kuroshio. Moreover, the unexpected typhoons in June2004 also contributed to the initial meander at the Tokara Strait. The result suggests an alternative meander mechanism of the Kuroshio path via the typhoon-eddy-Kuroshio interactions. It is argued that typhoons accompanied with cyclonic eddies, might play crucial roles in meanders of the Kuroshio. This will provide a more comprehensive understanding of the dynamics of the western boundary flows, like the Kuroshio and the Gulf.Third, the responses of the upper ocean to tropical cyclones south of Japan in Summer, 2004 were investigated by the observations of sea surface wind (SSW), sea surface temperature (SST), sea surface height anomaly (SSHA), chlorophyll-a (Chl-a) and Argo floats, etc. Typhoon Namtheun had notable impacts on the upper ocean along its track from July 26, 2004 to August 16, 2004. At the regions of the pre-existed cold eddy and beneath the track, the observed locations of upwelling, SSHA changes, SST cooling, Chl-a enhancement were consistent with each other, which implies that local processes (entrainment and upwelling) dominated the upper ocean responses in this case. Besides, there were cold tongues extending from the cold centers. The trajectories of Argo floats, along with the cold tongues, indicated that the surface advections caused the non-local processes. Finally, the mechanisms of the Chl-a concentration enhancement were sketched as the effects of both the local upwelling and the non-local advection. This study implies some non-local processes, e.g., horizontal advections, may play a notable role in the upper ocean responses to the typhoons. On the other hand, weak fast tropical cyclones Conson, Dianmu and Malou had few impacts on the upper ocean.
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