The impact of Kuroshio water on the source water of the southeastern Taiwan Strait: numerical results

Abstract

Model output from a Pacific basin-wide three-dimensional physical-biogeochemical model during the period of 1991 to 2008 was used to investigate the impact of Kuroshio water on the source water of the southeastern Taiwan Strait. Based on the characteristic salinities of both Kuroshio water and the South China Sea water, a Kuroshio impact index (KII) was designed to measure the degree of impact. The KII correlates significantly with the northeast-southwest component of wind stress, but the former lags the latter by approximately two months. The correlation coefficient between them increases from 0.267 4 to 0.852 9, with a lag time increasing from 0 to 63 days. The impact of Kuroshio Water is greater in winter and spring than in summer and autumn. At the interannual time scale, El Niño and La Niña events play an important role in impacting the KII. During El Niño events, more Kuroshio water contributes to the source water of the southeastern Taiwan Strait. Conversely, during La Niña events, less Kuroshio water contributes to the source water.Citation: Zhang Wenzhou, Zhuang Xuefen, Chen Chentung Arthur, Huang Tinghsuan. 2015. The impact of Kuroshio water on the source water of the southeastern Taiwan Strait: numerical results. Acta Oceanologica Sinica, 34(9): 23-34,

Physical drivers of chlorophyll variability in the open South China Sea

“…One water mass with high temperature and high salinity confirms the existence of Kuroshio intrusion water which has different properties from the SCS water [Gong et al, 1992;Liu et al, 2013]. Kuroshio intrusion appears as a transient event rather than a persistent circulation pattern [Yuan et al, 2006;Zhang et al, 2015b]. The salty intrusion water, sometimes trapped in the eddies shed from Kuroshio loop current in the Luzon Strait, can move westward along the continental slope of the northern SCS [Yuan et al, 2006].…”

“…The SCS is strongly influenced by the East Asian monsoon, northeasterly winds prevailing in winter and southwesterly winds in summer (June to August) [Chu et al, 1999;Zhang et al, 2015b]. In the mixed layer (Figure 3), the average temperature was lowest in winter due to strong wind mixing and negative net heat flux whereas it was highest in summer due to positive net heat flux dominating over wind mixing [Qu, 2001;Duan et al, 2012;Zhang et al, 2012].…”

“…The transition between them takes place in May and September. As a result, overall basin-scale circulation is cyclonic in winter but anti-cyclonic in summer [Chu et al, 1999;Hu et al, 2000;Zhang et al, 2015b]. In the northern SCS, surface currents originating from the Taiwan Strait and the Luzon Strait flow southwestward in winter, instead of northeastward currents in summer [Chu et al, 1999].…”

Exceptionally cold water days in the southern Taiwan Strait: their predictability and relation to La Niña

“…By contrast, when El Niño broke out in the winter seasons from 1997 to 1998, the warm water area (2 • C above the regional mean) in the TS increased by 25 % and nutrient concentrations decreased (Shang et al, 2005). Zhang et al (2015) suggested that less Kuroshio water enters the southeastern TS during La Niña than El Niño events, which might modulate the interannual variability in SST in the TS. However, less severe but longer lasting phenomena, such as SST variability, may have catastrophic consequences or can be a trigger for other threats (Ustrnul et al, 2015).…”

Exceptionally cold water days in the southern Taiwan Strait: their predictability and relation to La Niña

“…By contrast, when El Niño broke out in the winter seasons from 1997 to 1998, the warm water area (2°C above the regional mean) in the TS increased by 25% and nutrient concentrations decreased (Shang et al 10 2005). Zhang et al (2015) suggested that less Kuroshio water enters the southeastern TS during La Niña than El Niño events, which might modulate the interannual variability of SST in the TS. However, less severe but longer lasting phenomena, such as SST variability, may have catastrophic consequences or can be a trigger for other threats (Ustrnul et al 2015).…”