Abstract
As the spatio-temporal variability of the Kuroshio is highly influenced by mesoscale eddies, representing its seasonal variability characteristics requires sufficiently long term observations to reduce the uncertainties. Geostrophic velocity data estimated from hydrographic observation from 1987 to 2010 and the shipboard ADCP velocity data from 1993 to 2008 at the PN Section in the central East China Sea are collected to view the seasonal variability objectively. From both types of observation, it is found that the seasonal climatology mean of the Kuroshio Current exhibits significant difference in three areas, which are located at the Kuroshio Current core and its two flanks in a shallow layer less than 300 m, with the weakest northeast current at the core in autumn, the strongest counter current on the right flank in spring, and the strongest northeast current on the left flank in autumn, respectively. The seasonal variance of the Kuroshio Current also exhibits significant difference on the offshore side of the Kuroshio, with larger variance in spring and summer while smaller variance in autumn and winter. For the current parallel to the PN Section, the ratio of the seasonal variability component to the intraseasonal variability component is relatively smaller than that for the current perpendicular to the PN Section. Further analyses indicate that the seasonal variability at the PN Section is tightly linked to the upstream and downstream current variability.
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References
Andres M, Kwon Y O, Yang Jiayan. 2011. Observations of the Kuroshio's barotropic and baroclinic responses to basin-wide wind forcing. J Geophys Res Oceans, 116(C4), doi: 10.1029/2010JC006863
Andres M, Park J H, Wimbush M, et al. 2008. Study of the Kuroshio/Ryukyu Current system based on satellite-altimeter and in situ measurements. J Oceanogr, 64(6): 937–950
Andres M, Park J H, Wimbush M, et al. 2009. Manifestation of the Pacific decadal oscillation in the Kuroshio. Geophysical Research Letters, 36(16), doi: 10.1029/2009GL039216
Brown M B, Forsythe A B. 1974. Robust tests for the equality of variances. Journal of the American Statistical Association, 69(346): 364–367
Fujiwara I, Hanzawa Y, Eguchi I, et al. 1987. Seasonal oceanic conditions on a fixed line in the East China Sea. The Oceanographical Magazine, 37: 37–46
Guan Bingxian. 1988. Major features and variability of the Kuroshio in the East China Sea. Chin J Oceanol Limnol, 6(1): 35–48
Guo Xinyu, Miyazawa Y, Yamagata T. 2006. The Kuroshio onshore intrusion along the shelf break of the East China Sea: the origin of the Tsushima Warm Current. J Phys Oceanogr, 36(12): 2205–2231
Hinata T. 1996. Seasonal variation and long-term trends of the oceanographic conditions along a fixed hydrographic line crossing the Kuroshio in the East China Sea. The Oceanographical Magazine, 45: 9–32
Hisaki Y, Imadu C. 2009. Southward recirculation of the East China Sea Kuroshio west of Okinawa Island. J Geophys Res, 114(C6): C06013, doi: 10.1029/2008JC004943
Hu Xiaomin, Xiong Xuejun, Qiao Fangli, et al. 2008. Surface current field and seasonal variability in the Kuroshio and adjacent regions derived from satellite-tracked drifter data. Acta Oceanologica Sinica, 27(3): 11–29
Ichikawa H, Beardsley R C. 1993. Temporal and spatial variability of volume transport of the Kuroshio in the East China Sea. Deep-Sea Research Part I: Oceanographic Research Papers, 40(3): 583–605
Isobe A. 2000. Two-layer model on the branching of the Kuroshio southwest of Kyushu, Japan. J Phys Oceanogr, 30(9): 2461–2476
Kagimoto T, Yamagata T. 1997. Seasonal Transport Variations of the Kuroshio: An OGCM Simulation. J Phys Oceanogr, 27(3): 403–418
Kawabe M. 1988. Variability of Kuroshio velocity assessed from the sea-level difference between Naze and Nishinoomote. Journal of the Oceanographical Society of Japan, 44(6): 293–304
Lee T N, Johns W E, Liu C T, et al. 2001. Mean transport and seasonal cycle of the Kuroshio east of Taiwan with comparison to the Florida Current. J Geophys Res, 106(C10): 22143–22158
Liu Yonggang, Yuan Yaochu. 1999. Variability of the Kuroshio in the East China Sea in 1993 and 1994. Acta Oceanologica Sinica, 18(1): 17–36
Mantua N J, Hare S R, Zhang Yuan, et al. 1997. A Pacific interdecadal climate oscillation with impacts on salmon production. Bull Amer Meteor Soc, 78(6): 1069–1079
Na H, Wimbush M, Park J H, et al. 2014. Observations of flow variability through the Kerama Gap between the East China Sea and the Northwestern Pacific. J Geophys Res Oceans, 119(2): 689–703
Nitani H. 1972. Beginning of the Kuroshio. In: Stommel H, Yoshida K, eds. Kuroshio, Physical Aspects of the Japan Current. Seattle, U S: University of Washington Press, 129–164
Oey L Y, Hsin Y C, Wu C R. 2010. Why does the Kuroshio northeast of Taiwan shift shelfward in winter?. Ocean Dyn, 60(2): 413–426
Oka E, Kawabe M. 1998. Characteristics of variations of water properties and density structure around the Kuroshio in the East China Sea. J Oceanogr, 54(6): 605–617
Soeyanto E, Guo Xinyu, Ono J, et al. 2014. Interannual variations of Kuroshio transport in the East China Sea and its relation to the Pacific Decadal Oscillation and mesoscale eddies. J Geophys Res Oceans, 119(6): 3595–3616
Su Jilan, Guan Bingxian, Jiang Jingzhong. 1990. The Kuroshio, Part 1, Physical features. Oceanogr Mar Biol Annu Rev, 28: 11–71
Tang T Y, Tai J H, Yang Y J. 2000. The flow pattern north of Taiwan and the migration of the Kuroshio. Cont Shelf Res, 20(4–5): 349–371
Teague W J, Jacobs G A, Ko D S, et al. 2003. Connectivity of the Taiwan, Cheju, and Korea straits. Cont Shelf Res, 23(1): 63–77
Wei Yanzhou, Huang Daji, Zhu Xiaohua. 2013. Interannual to decadal variability of the Kuroshio Current in the East China Sea from 1955 to 2010 as indicated by in-situ hydrographic data. J Oceanogr, 69(5): 571–589
Yamashiro T, Maeda A, Sakurai M, et al. 1990. Mean velocity distribution and transport of the Kuroshio referred to GEK surface velocity in the East China Sea. Umi to Sora (Sea and Sky) (in Japanese), 66(3): 181–190
Yuan Yaochu, Kaneko A, Su Jilan, et al. 1998. The Kuroshio east of Taiwan and in the East China Sea and the currents east of Ryukyu Islands during early summer of 1996. J Oceanogr, 54(3): 217–226
Yuan Yaochu, Liu Yonggang, Su Jilan. 2001. Variability of the Kuroshio in the East China Sea during El-Nino to La-Niña Phenomenon of 1997 and 1998. Chinese Journal of Geophysics, 44(2): 196–207
Zhang Dongxiao, Lee T N, Johns W E, et al. 2001. The Kuroshio east of Taiwan: Modes of variability and relationship to interior ocean mesoscale eddies. J Phys Oceanogr, 31(4): 1054–1074
Zhang Ronghua, Levitus S. 1997. Structure and cycle of decadal variability of upper-ocean temperature in the North Pacific. Journal of Climate, 10(4): 710–727
Zhu Xiaohua, Huang Daji, Guo Xinyu. 2010. Autumn intensification of the Ryukyu Current during 2003–2007. Science China Earth Sciences, 53(4): 603–609
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Foundation item: The National Basic Research Program (973 Program) of China under contract Nos 2012CB956000 and 2011CB409803; the National Natural Science Foundation of China under contract Nos 41475101, 41421005, and 41276028; the Natural Science Foundation of China-Shandong Joint Fund for Marine Science Research Centers under contract No. U1406401; the Strategic Priority Project of Chinese Academy of Sciences under contract Nos XDA11010301 and XDA11020306.
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Wei, Y., Pei, Y. & Zhang, RH. Seasonal variability of the Kuroshio Current at the PN Section in the East China Sea based on in-situ observation from 1987 to 2010. Acta Oceanol. Sin. 34, 12–21 (2015). https://doi.org/10.1007/s13131-015-0662-3
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DOI: https://doi.org/10.1007/s13131-015-0662-3