Variations Of Thermal Transport Of The Kuroshio In East Of Taiwan And Its Impact On Kuroshio Intrusion

The Kuroshio is the world famous north-flowing boundary current on the west side of the North Pacific Ocean.It is characteristically fast,intense,deep and narrow,with relatively higher temperature and salinity.Kuroshio has plenty of heat,it is the main channel for the tropical Pacific Ocean transport heat to the Middle East China Sea.The Kuroshio Current plays a crutial role in the offshore circulation of East China Sea,heat and salt transport,multi-scale ocean physics,marine environment,marine resources and the global balance of energy and so on.At the same time,the seasonal and inter-annual variations of Kuroshio exist exserts significant influence over climate variability in the coastal areas of China.Based on previous studies,the seasonal and inter-annual variations of the volume transport and heat transport of Kuroshio from 1993 to 2012 are studied by analyzing the JCOPE2?Japan Coastal Ocean Predictability Experiment 2?dataset at the 24°N section east of Taiwan,the NET section of northeastern Taiwan and the PN section.JCOPE2 was developed from POM which is a high-resolution?1/12 °?numerical mode.The results indicate that:The Kuroshio is the most?least?intense and wide in summer?winter?.The volume transport and heat transport of Kuroshio has strong seasonal and inter-annual variations at the 24°N section.The volume transport of Kuroshio is the largest in summer?26.41 Sv?and spring?26.15 Sv?,and smaller in autumn?24.43 Sv?,and smallest in winter?23.26 Sv?.Annual mean of volume transport through the 240N section of the east Taiwan is 24.76 Sv.It is more consistent with the historical research.From 1993 to 2012,the inter-annual variations of volume transport of Kuroshio has a decreasing trend and the volume transport of Kuroshio is larger before 2003 and smaller after 2003 at 24°N section.A maximum value?41.12 Sv?of volume transport of Kuroshio appeared in August 2008.A minimum value?7.12 Sv?of volume transport of Kuroshio appeared in March 1993.The volume transport of Kuroshio is the largest in spring?13.84 Sv?and smallest in autumn?10.76 Sv?,winter?12.42 Sv?and summer?12.61 Sv?was followed at the NET section.Annual mean of through the NET section is 12.41 Sv.Average years of volume transport of Kuroshio has a small variable amplitude in winter,summer and spring.Unlike 24°N section,the volume transport of Kuroshio has a linear increasing trend at NET section from 1993 to 2012,and a maximum value?20.25 Sv?of volume transport of Kuroshio appeared in June 1996.A minimum value?-5.33 Sv?of volume transport of Kuroshio appeared in November 2006.The volume transport of Kuroshio is the largest in summer?31.63 Sv?and spring?30.11 Sv?,and smaller in winter?30.09 Sv?and autumn?29.61 Sv?at PN section.Annual mean of through the PN section is 30.35 Sv.The volume transport of Kuroshio has a long-term linear increasing trend at PN section,but the reduced amplitude is very small.A maximum value?38.44 Sv?of volume transport of Kuroshio appeared in Agust2001.A minimum value?23.41 Sv?of volume transport of Kuroshio appeared in April 1993.The heat transport of Kuroshio east of Taiwan has obvious seasonal and interannual variation characteristics.The heat transport of Kuroshio is the strongest in summer(2.10×10¹⁴ W)and spring(2.00×10¹⁴ W),and smaller in autumn(1.90×10¹⁴ W),and smallest in winter(1.76×10¹⁴ W).Similarly,the heat transport through PN maximizes in summer with a value of 2.36×10¹⁴ W,while it minimizes in winter with a value of 2.04×10¹⁴ W.Annual mean of heat transport is 1.94×10¹⁴ W and 2.16× 10¹⁴ W at the 24°N and PN section,respectively.The heat transport of Kuroshio has a long-term linear decreasing trend transport through 24°N and PN section.However,the heat transport through NET section reaches the maximum?minimum?of 1.12×10¹⁴(0.91 ×10¹⁴)W in spring?autumn?with annual mean of 1.02× 10¹⁴ W.There is a linear increasing trend in the heat transport for 20 years,while its magnitude is small and the long-term trends in foure seasons are dissimilar.Maximum(2.84×10¹⁴ W)and minimum(1.56×10¹⁴ W)values appear in the August 2001 and April 1993,respectively.The variability of the heat transport of Kuroshio in east of Taiwan is mainly influenced by the volume transport from the low latitudes area,Secondly,the variability of the heat transport of Kuroshio in east of Taiwan is influenced by water temperatures.Its seasonal variations are mainly affected by the monsoon and warm eddy in east of Taiwan.The heat transport of Kuroshio has a long linear decreasing trend from 1993 to 2012,while its decreasing rate is small.The wavelet analysis indicates that,the heat transport of Kuroshio in east of Taiwan presents notable quasi-2a and around 7a variations which was for subject to temporal variety.This periodic change is closed to North Pacific PDO index.Kuroshio intrusion is the greatest in spring and summer,the weakest in autumn and winter of northeastern Taiwan.There is a linear increasing trend in the intrusion for 20 years,Kuroshio intrusion in northeast of Taiwan mainly influenced by topography and Ekman transport caused by monsoon.