Abstract
Using observations and numerical simulations, this study examines the intraseasonal variability of the surface zonal current (u ISV) over the equatorial Indian Ocean, highlighting the seasonal and spatial differences, and the causes of the differences. Large-amplitude u ISV occurs in the eastern basin at around 80°–90°E and near the western boundary at 45°–55°E. In the eastern basin, the u ISV is mainly caused by the atmospheric intraseasonal oscillations (ISOs), which explains 91% of the standard deviation of the total u ISV. Further analysis suggests that it takes less than ten days for the intraseasonal zonal wind stress to generate the u ISV through the directly forced Kelvin and Rossby waves. Driven by the stronger zonal wind stress associated with the Indian summer monsoon ISO (MISO), the eastern u ISV in boreal summer (May to October) is about 1.5 times larger than that in boreal winter (November to April). In the western basin, both the atmospheric ISOs and the oceanic internal instabilities contribute substantially to the u ISV, and induce stronger u ISV in boreal summer. Energy budget analysis suggests that the mean flow converts energy to the intraseasonal current mainly through barotropic instabilities.
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References
Adames Á F, Kim D. 2015. The MJO as a dispersive, convectively coupled moisture wave: theory and observations. Journal of the Atmospheric Sciences, 73(3): 913–941
Atlas R, Ardizzone J, Hoffman R N. 2008. Application of satellite surface wind data to ocean wind analysis. In: Proceedings of SPIE-The International Society for Optical Engineering 7087, doi: https://doi.org/10.1117/12.795371
Bentamy A, Fillon D C. 2012. Gridded surface wind fields from Metop/ASCAT measurements. International Journal of Remote Sensing, 33(6): 1729–1754, doi: https://doi.org/10.1080/01431161.2011.600348
Brandt P, Dengler M, Rubino A, et al. 2003. Intraseasonal variability in the southwestern Arabian Sea and its relation to the seasonal circulation. Deep-Sea Research Part II: Topical Studies in Oceanography, 50(12/13): 2129–2141, doi: https://doi.org/10.1016/S0967-0645(03)00049-3
Chassignet E P, Hurlburt H E, Smedstad O M, et al. 2006. Ocean prediction with the hybrid coordinate ocean model (HYCOM). In: Chassignet E P, Verron J, eds. Ocean Weather Forecasting: An Integrated View of Oceanography. Dordrecht: Springer, 413–426
Chatterjee P, Goswami B N. 2004. Structure, genesis and scale selection of the tropical quasi-biweekly mode. Quarterly Journal of the Royal Meteorological Society, 130(599): 1171–1194, doi: https://doi.org/10.1256/qj.03.133
Chen Gengxin, Han Weiqing, Li Yuanlong, et al. 2015. Seasonal-to-interannual time-scale dynamics of the equatorial undercurrent in the Indian Ocean. Journal of Physical Oceanography, 45(6): 1532–1553
Chen Gengxin, Han Weiqing, Li Yuanlong, et al. 2017. Strong intraseasonal variability of meridional currents near 5°N in the eastern Indian Ocean: characteristics and causes. Journal of Physical Oceanography, 47(5): 979–998, doi: https://doi.org/10.1175/JPO-D-16-0250.1
Chen Gengxin, Han Weiqing, Li Yuanlong, et al. 2019. Intraseasonal variability of the equatorial undercurrent in the Indian Ocean. Journal of Physical Oceanography, 49(1): 85–101, doi: https://doi.org/10.1175/JPO-D-18-0151.1
Chen Gengxin, Wang Qiang, Chu Xiaoqing. 2021. Accelerated spread of Fukushima’s waste water by ocean circulation. The Innovation, 2(2): 100119, doi: https://doi.org/10.1016/j.xinn.2021.100119
Chen Gengxin, Wang Dongxiao, Han Weiqing, et al. 2020. The extreme El Nino events suppressing the intraseasonal variability in the eastern tropical Indian ocean. Journal of Physical Oceanography, 50(8): 2359–2372, doi: https://doi.org/10.1175/JPO-D-20-0041.1
Dasgupta P, Metya A, Naidu C V, et al. 2020. Exploring the long-term changes in the Madden Julian Oscillation using machine learning. Scientific Reports, 10(1): 18567, doi: https://doi.org/10.1038/s41598-020-75508-5
Dey A, Chattopadhyay R, Sahai A K, et al. 2019. An operational tracking method for the MJO using extended empirical orthogonal functions. Pure and Applied Geophysics, 176(6): 2697–2717, doi: https://doi.org/10.1007/s00024-018-2066-8
Duan Yongliang, Liu Hongwei, Yu Weidong, et al. 2019. The onset of the Indonesian-Australian summer monsoon triggered by the first-branch eastward-propagating Madden-Julian oscillation. Journal of Climate, 32(17): 5453–5470, doi: https://doi.org/10.1175/JCLI-D-18-0513.1
Farrar J T, Weller R A. 2006. Intraseasonal variability near 10°N in the eastern tropical Pacific Ocean. Journal of Geophysical Research: Oceans, 111(C5): C05015
Han Weiqing. 2005. Origins and dynamics of the 90-day and 30–60-day variations in the equatorial Indian Ocean. Journal of Physical Oceanography, 35(5): 708–728, doi: https://doi.org/10.1175/JPO2725.1
Han Weiqing, Lawrence D A, Webster P J. 2001. Dynamical response of equatorial Indian Ocean to intraseasonal winds: zonal flow. Geophysical Research Letters, 28(22): 4215–4218, doi: https://doi.org/10.1029/2001GL013701
Han Weiqing, Webster P, Lukas R, et al. 2004. Impact of atmospheric intraseasonal variability in the Indian Ocean: low-frequency rectification in equatorial surface current and transport. Journal of Physical Oceanography, 34(6): 1350–1372, doi: https://doi.org/10.1175/1520-0485(2004)034<1350:IOAIVI>2.0.CO;2
Hazra A, Krishnamurthy V. 2018. Seasonality and mechanisms of tropical intraseasonal oscillations. Climate Dynamics, 50(1): 179–199
Hendon H H, Liebmann B, Glick J D. 1998. Oceanic kelvin waves and the Madden-Julian Oscillation. Journal of the Atmospheric Sciences, 55(1): 88–101, doi: https://doi.org/10.1175/1520-0469(1998)055<0088:OKWATM>2.0.CO;2
Iskandar I. 2011. Intraseasonal variations of near-surface zonal current observed in the south-eastern equatorial Indian ocean. Journal of Coastal Zone Management, 15(1): 1–8
Iskandar I, McPhaden M J. 2011. Dynamics of wind-forced intraseasonal zonal current variations in the equatorial Indian Ocean. Journal of Geophysical Research: Oceans, 116(C6): C06019
Jiang Xianan, Li T, Wang Bin. 2004. Structures and mechanisms of the northward propagating boreal summer intraseasonal oscillation. Journal of Climate, 17(5): 1022–1039, doi: https://doi.org/10.1175/1520-0442(2004)017<1022:SAMOTN>2.0.CO;2
Jin D, Murtugudde R, Waliser D E. 2012. Tropical Indo-Pacific Ocean chlorophyll response to MJO forcing. Journal of Geophysical Research: Oceans, 117(C11): C11008
Joseph S, Wallcraft A J, Jensen T G, et al. 2012. Weakening of spring Wyrtki jets in the Indian Ocean during 2006–2011. Journal of Geophysical Research: Oceans, 117(C4): C04012
Kemball-Cook S, Wang Bin. 2001. Equatorial waves and air-sea interaction in the boreal summer intraseasonal oscillation. Journal of Climate, 14(13): 2923–2942, doi: https://doi.org/10.1175/1520-0442(2001)014<2923:EWAASI>2.0.CO;2
Kessler W S, McPhaden M J, Weickmann K M. 1995. Forcing of intraseasonal kelvin waves in the equatorial Pacific. Journal of Geophysical Research: Oceans, 100(C6): 10613–10631, doi: https://doi.org/10.1029/95JC00382
Kikuchi K, Wang Bin. 2010. Formation of tropical cyclones in the northern Indian Ocean associated with two types of tropical intraseasonal oscillation modes. Journal of the Meteorological Society of Japan: Ser II, 88(3): 475–496
Kikuchi K, Wang Bin, Kajikawa Y. 2012. Bimodal representation of the tropical intraseasonal oscillation. Climate Dynamics, 38(9–10): 1989–2000, doi: https://doi.org/10.1007/s00382-011-1159-1
Kiladis G N, Dias J, Straub K H, et al. 2014. A comparison of OLR and circulation-based indices for tracking the MJO. Monthly Weather Review, 142(5): 1697–1715, doi: https://doi.org/10.1175/MWR-D-13-00301.1
Kindle J C, Thompson J D. 1989. The 26- and 50-day oscillations in the western Indian Ocean: model results. Journal of Geophysical Research: Oceans, 94(C4): 4721–4736, doi: https://doi.org/10.1029/JC094iC04p04721
Lau W K M, Waliser D E. 2012. El Niño Southern Oscillation connection. In: Lau W K M, Waliser D E, eds. Intraseasonal Variability in the Atmosphere-Ocean Climate System. Berlin: Springer, 297–334
Lawrence D M, Webster P J. 2002. The boreal summer intraseasonal oscillation: relationship between northward and eastward movement of convection. Journal of the Atmospheric Sciences, 59(9): 1593–1606, doi: https://doi.org/10.1175/1520-0469(2002)059<1593:TBSI-OR>2.0.CO;2
Li Yuanlong, Han Weiqing, Shinoda T, et al. 2013. Effects of the diurnal cycle in solar radiation on the tropical Indian Ocean mixed layer variability during wintertime Madden-Julian Oscillations. Journal of Geophysical Research Oceans, 118(10): 4945–4964
Li Yuanlong, Han Weiqing, Shinoda T, et al. 2014. Revisiting the wintertime intraseasonal SST variability in the tropical South Indian Ocean: impact of the ocean interannual variation. Journal of Physical Oceanography, 44(7): 1886–1907, doi: https://doi.org/10.1175/JPO-D-13-0238.1
Li Yuanlong, Han Weiqing, Lee Tong. 2015. Intraseasonal sea surface salinity variability in the equatorial Indo-Pacific Ocean induced by Madden-Julian oscillations. Journal of Geophysical Research: Oceans, 120(3): 2233–2258
Li Yuanlong, Han Weiqing, Wang Wanqiu, et al. 2017. Bay of Bengal salinity stratification and Indian summer monsoon intraseasonal oscillation: 2. Impact on SST and convection. Journal of Geophysical Research: Oceans, 122(5): 4312–4328
Liebmann B, Smith C A. 1996. Description of a complete (interpolated) outgoing longwave radiation dataset. Bulletin of the American Meteorological Society, 77(6): 1275–1277
Luyten J R, Roemmich D H. 1982. Equatorial currents at semi-annual period in the Indian Ocean. Journal of Physical Oceanography, 12(5): 406–413, doi: https://doi.org/10.1175/1520-0485(1982)012<0406:ECASAP>2.0.CO;2
Madden R A, Julian P R. 1971. Detection of a 40–50 day oscillation in the zonal wind in the tropical Pacific. Journal of the Atmospheric Sciences, 28(5): 702–708, doi: https://doi.org/10.1175/1520-0469(1971)028<0702:DOADOI>2.0.CO;2
Masumoto Y, Hase H, Kuroda Y, et al. 2005. Intraseasonal variability in the upper layer currents observed in the eastern equatorial Indian Ocean. Geophysical Research Letters, 32(2): L02607
McPhaden M J, Meyers G, Ando K, et al. 2009. Supplement to RAMA: the research moored array for African—Asian—Australian monsoon analysis and prediction. Bulletin of the American Meteorological Society, 90(4): ES5–ES8
Mysak L A, Mertz G A. 1984. A 40- to 60-day oscillation in the source region of the Somali current during 1976. Journal of Geophysical Research: Oceans, 89(C1): 711–715, doi: https://doi.org/10.1029/JC089iC01p00711
Nagura M, McPhaden M J. 2012. The dynamics of wind-driven intraseasonal variability in the equatorial Indian Ocean. Journal of Geophysical Research:Oceans, 117(C2): C02001
Oey Lie-Yauw. 2008. Loop current and deep eddies. Journal of Physical Oceanography. Journal of Physical Oceanography, 38(7): 1426–1499, doi: 38.10.1175/2007JPO3818.1
Reppin J, Schott F A, Fischer J, et al. 1999. Equatorial currents and transports in the upper central Indian Ocean: annual cycle and interannual variability. Journal of Geophysical Research: Oceans, 104(C7): 15495–15514, doi: https://doi.org/10.1029/1999JC900093
Schott F, Fieux M, Kindle J, et al. 1988. The boundary currents east and north of Madagascar: 2. Direct measurements and model comparisons. Journal of Geophysical Research: Oceans, 93(C5): 4963–4974, doi: https://doi.org/10.1029/JC093iC05p04963
Schott F A, McCreary Jr. J P. 2001. The monsoon circulation of the Indian Ocean. Progress in Oceanography, 51(1): 1–123, doi: https://doi.org/10.1016/S0079-6611(01)00083-0
Schott F A, Xie S P, McCreary Jr. J P. 2009. Indian Ocean circulation and climate variability. Reviews of Geophysics, 47(1): RG1002
Senan R, Sengupta D, Goswami B N. 2003. Intraseasonal “monsoon jets” in the equatorial Indian Ocean. Geophysical Research Letters, 30(14): 1750
Sengupta D, Senan R, Goswami B N. 2001. Origin of intraseasonal variability of circulation in the tropical central Indian Ocean. Geophysical Research Letters, 28(7): 1267–1270, doi: https://doi.org/10.1029/2000GL012251
Shinoda T, Han Weiqing. 2005. Influence of the Indian Ocean dipole on atmospheric subseasonal variability. Journal of Climate, 18(18): 3891–3909, doi: https://doi.org/10.1175/JCLI3510.1
Shinoda T, Roundy P E, Kiladis G N. 2008. Variability of intraseasonal Kelvin waves in the equatorial Pacific Ocean. Journal of Physical Oceanography, 38(5): 921–944, doi: https://doi.org/10.1175/2007JPO3815.1
Sikka D R, Gadgil S. 1980. On the maximum cloud zone and the ITCZ over Indian longitudes during the southwest monsoon. Monthly Weather Review, 108(11): 1840–1853, doi: https://doi.org/10.1175/1520-0493(1980)108<1840:OTMCZA>2.0.CO;2
Suhas E, Neena J M, Goswami B N. 2013. An Indian Monsoon Intraseasonal Oscillations (MISO) index for real time monitoring and forecast verification. Climate Dynamics, 40(11–12): 2605–2616, doi: https://doi.org/10.1007/s00382-012-1462-5
Swallow J C, Fieux M. 1982. Historical evidence for two gyres in the Somali Current. Journal of Marine Research, 40: 747–755
Wang S G, Ma D, Sobel A H, et al. 2018. Propagation characteristics of BSISO Indices. Geophysical Research Letters, 45(18): 9934–9943, doi: https://doi.org/10.1029/2018GL078321
Wang F, Wang J N, Guan C, et al. 2016. Mooring observations of equatorial currents in the upper 1000 m of the western Pacific Ocean during 2014. Journal of Geophysical Research: Oceans, 121(6): 3730–3740, doi: https://doi.org/10.1002/2015JC011510
Wheeler M C, Hendon H H. 2004. An all-season real-time multivariate MJO index: development of an index for monitoring and prediction. Monthly Weather Review, 132(8): 1917–1932, doi: https://doi.org/10.1175/1520-0493(2004)132<1917:AARMMI>2.0.CO;2
Wyrtki K. 1973. An equatorial jet in the Indian Ocean. Science, 181(4096): 262–264, doi: https://doi.org/10.1126/science.181.4096.262
Weisberg R H, Wang C. 1997. Slow variability in the equatorial west-central Pacific in relation to ENSO. Journal of Climate, 10(8): 1998–2017
Xuan Lili, Qiu Yun, Xu Jindian, et al. 2014. Seasonal variation of surface-layer circulation in the eastern tropical Indian Ocean. Journal of Tropical Oceanography, 33(1): 26–35
Xue Huijie, Bane Jr. J M. 1997. A numerical investigation of the Gulf Stream and its meanders in response to cold air outbreaks. Journal of Physical Oceanography, 27(12): 2606–2629, doi: https://doi.org/10.1175/1520-0485(1997)027<2606:ANIOTG>2.0.CO;2
Yasunari T. 1980. A quasi-stationary appearance of 30 to 40 day period in the cloudiness fluctuations during the summer monsoon over India. Journal of the Meteorological Society of Japan: Ser II, 58(3): 225–229
Zhang Zhixiang, Pratt Larry, Wang, Fan, et al. 2020. Intermediate intraseasonal variability in the western tropical Pacific Ocean: meridional distribution of equatorial Rossby Waves influenced by a tilted boundary. Journal of Physical Oceanography, 50(4): 921–933, doi: 50.10.1175/JPO-D-19-0184.1
Zhou Lei, Murtugudde R. 2010. Influences of Madden-Julian Oscillations on the eastern Indian Ocean and the maritime continent. Dynamics of Atmospheres and Oceans, 50(2): 257–274, doi: https://doi.org/10.1016/j.dynatmoce.2009.12.003
Zhu Baozhen, Wang Bin. 1993. The 30–60-day convection seesaw between the tropical Indian and western Pacific Oceans. Journal of the Atmospheric Sciences, 50(2): 184–199, doi: https://doi.org/10.1175/1520-0469(1993)050<0184:TDCSBT>2.0.CO;2
Zhuang Wei, Xie Shangping, Wang Dongxiao, et al. 2010. Intraseasonal variability in sea surface height over the South China Sea. Journal of Geophysical Research: Oceans, 115(C4): C04010
Acknowledgements
The RAMA data was obtained at https://www.pmel.noaa.gov/gtmba/pmel-theme/indian-ocean-rama. The CCMP data are available online at http://data.remss.com/ccmp/v02.0/, and the details are retrieved from https://climatedataguide.ucar.edu/climate-data/ccmp-cross-calibrated-multi-platform-wind-vector-analysis. The OLR data and detailed description are at http://www.esrl.noaa.gov/psd/data/gridded/data.olrcdr.interp.html. The OMI index and the EOFs at https://psl.noaa.gov/mjo/mjoindex. The bimodal index and the details are from http://iprc.soest.hawaii.edu/users/kazuyosh/Bimodal_ISO.html. This study is supported by the China-Sri Lanka Joint Center for Education and Research in the Chinese Academy of Sciences. The numerical simulation is supported by the High Performance Computing Division in the South China Sea Institute of Oceanology.
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Foundation item: The National Natural Science Foundation of China under contract Nos 41822602, 41976016 and 4207602; the Strategic Priority Research Program of Chinese Academy of Sciences under contract Nos XDB42000000, XDA20060502 and XDA15020901; the Guangdong Basic and Applied Basic Research Foundation under contract No. 2021A1515011534; the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou) under contract Nos GML2019ZD0302 and GML2019ZD0306; the fund of Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences under contract No. ISEE2021ZD01; the fund of State Key Laboratory of Tropical Oceanography under contract No. LTOZZ2002; the fund of Youth Innovation Promotion Association of Chinese Academy of Sciences under contract No. Y2021093.
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Zhong, Q., Chen, G., Li, Y. et al. Intraseasonal variability of the surface zonal current in the equatorial Indian Ocean: Seasonal differences and causes. Acta Oceanol. Sin. 41, 12–26 (2022). https://doi.org/10.1007/s13131-021-1935-7
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DOI: https://doi.org/10.1007/s13131-021-1935-7