Movement of the Kuroshio axis to the northeast shelf of Taiwan during typhoon events

Morimoto, Akihiko; Kojima, Soichi; Jan, Sen; Takahashi, Daisuke

doi:10.1016/j.ecss.2009.02.022

Cited by 48 publications

(49 citation statements)

References 10 publications

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“…It is known that southerly typhoon winds of long duration are also important in pushing the Kuroshio axis onto the shelf [Morimoto et al, 2009]. The linkage of these two pieces of evidence can be explained as follows: long-lasting southerly winds force coastal upwelling along the east coast of Taiwan, generating an east -west sea level gradient that in turn leads to a northward geostrophic current.…”

Section: Main Factors Determining Variation In Primary Productivity Ementioning

confidence: 99%

“…The lowest PP enh (0.26 Gg C) was caused by Nock-Ten, which had a relatively fast TS (6.93 m s À1 ) and the strongest northerly wind (À10.46 m s À1 ). The northerly wind did not push the Kuroshio current axis shelfward, which meant that the upwelling of nutrients was unlikely to be enhanced [see Morimoto et al, 2009]. Other typhoon events (Bilis and Longwang) that caused a Kuroshio shelfward shift were also followed by clear Chl-a blooms, SST cooling, and PP enh bands (see auxiliary material).…”

Section: Main Factors Determining Variation In Primary Productivity Ementioning

confidence: 99%

“…Typhoon variables including typhoon translation speed (TS, m s À1 ) and maximum sustained wind speed (MSW, m s À1 ) were obtained from the Japan Meteorological Agency (JMA). We also analyzed JMA meridional wind speed (V, m s À1 ) at Yonaguni Island (YI, Figure 1a), as during a typhoon event the southerly wind is important in driving the Kuroshio current onto the shelf [Morimoto et al, 2009].…”

Section: Methodsmentioning

confidence: 99%

“…Such a northward geostrophic current accelerates the Kuroshio current, and thus the Kuroshio current axis shifts from its normal northeast -southwest direction to a north -south direction, causing it to move shelfward. This enhances the upwelling of subsurface Kuroshio water onto the shelf, increasing the nutrient load on the shelf [e.g., Chen et al, 2003a;Morimoto et al, 2009]. The upwelled nutrients would seem to non-linearly enhance PP [Dugdale, 1985] to a greater extent than when there is no shelfward movement of the Kuroshio current, resulting in a non-linear relationship between PP enh and V (Figure 2b).…”

Section: Main Factors Determining Variation In Primary Productivity Ementioning

confidence: 99%

“…It has been suggested that cross-shelf typhoon passages in the vicinity of Taiwan push the Kuroshio current axis shelfward [e.g., Chen et al, 2003a, Morimoto et al, 2009 and lead to the upwelling of subsurface Kuroshio water, inevitably enhancing phytoplankton chlorophyll-a (Chl-a, mg m À3 ) and PP [Chen et al, 2003a].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Enhancement of phytoplankton primary productivity in the southern East China Sea following episodic typhoon passage

Siswanto

Morimoto

Kojima

2009

Geophysical Research Letters

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The enhancement of primary productivity (PPenh) in the southern East China Sea (ECS) following 16 typhoon passages was investigated using ocean color data and a primary productivity model. PPenh tended to be higher when typhoons traversed slowly with trajectories that allowed strong southerly winds to prevail over Yonaguni Island. Such long‐lasting southerly winds were believed to push the Kuroshio current axis shelfward, enhancing the upwelling of nutrients, hence promoting new productivity (NP). The importance of long‐lasting southerly winds as a proxy for physical perturbations underlying PPenh was expressed by an empirical equation by which 88% of PPenh variation could be explained. Applying this equation, we assessed that typhoon passages accounted for a minimum of 0.6–11.8% of the ECS summer–fall NP, suggesting that typhoon passage over the southern ECS is an important phenomenon supporting NP in the ECS.

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Section: Main Factors Determining Variation In Primary Productivity Ementioning

confidence: 99%

Section: Main Factors Determining Variation In Primary Productivity Ementioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Main Factors Determining Variation In Primary Productivity Ementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Enhancement of phytoplankton primary productivity in the southern East China Sea following episodic typhoon passage

Siswanto

Morimoto

Kojima

2009

Geophysical Research Letters

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Dynamic and thermal responses of the Kuroshio to typhoon Megi (2004)

Wei

Liu

Wang

2014

Geophysical Research Letters

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Relatively weak hurricane-induced cooling (<1°C) is often observed in the Loop Current, while observed sea surface temperature (SST) cooling is much stronger in the Kuroshio. This was previously attributed to strong advection effects by the Loop Current. Based on a budget analysis, this study quantitatively diagnoses the dynamic and thermal responses of the Kuroshio to typhoon Megi and four additional tropical cyclones (TCs), which produce up to~3°C SST cooling within the Kuroshio itself. The results show that the surface thermal response of the Kuroshio is a wind-induced temperature cooling primarily due to vertical mixing (up to 96%). The dynamic response of the Kuroshio depends not only on TC conditions (intensity and wind direction) but also on prestorm ocean conditions (e.g., ocean mixed layer depth, baroclinicity, and current velocity). Differently from the open ocean where the ocean gains kinetic energy mainly from wind stress work, the Kuroshio can obtain greater kinetic energy from its baroclinic pressure work, especially in the upper ocean. The strong SST cooling observed in the Kuroshio region is therefore likely associated with the kinetic energy extracted from the Kuroshio baroclinic potential energy, which greatly enhances local vertical mixing.

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

Bai

Chen

et al. 2014

JGR Oceans

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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 Taiwan's 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 cyclonedriven terrestrial material transport could be another source of mud in the southern Okinawa Trough.

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Movement of the Kuroshio axis to the northeast shelf of Taiwan during typhoon events

Cited by 48 publications

References 10 publications

Enhancement of phytoplankton primary productivity in the southern East China Sea following episodic typhoon passage

Enhancement of phytoplankton primary productivity in the southern East China Sea following episodic typhoon passage

Dynamic and thermal responses of the Kuroshio to typhoon Megi (2004)

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

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