The observational data from the International Nusantara Stratification and Transport (INSTANT) Program is used to investigate the variation of the Indonesian Throughflow (ITF). Specifically, the power spectrum of the flow in surface and thermocline layers in the three major outflow passages is analyzed. The results show that the flow in the surface layer of the Lombok and Ombai straits has an obvious annual cycle. During the monsoon transition period, the flow reverses at all depths at the Lombok and Ombai straits, whereas the current reveres only below 300 m in the Timor Passage. The variations of the currents in both surface and thermocline layers are high at intraseasonal time scale. The annual cycle is prevalent in surface layer, while the semiannual cycle dominates in thermocline layer. At tidal frequencies, each strait shows that the semi-diurnal tide M2 is dominant expect for the surface layer of the Lombok Strait where the diurnal tide K1 is dominant.
LIU Kai
,
SUN Zhao-Bo
,
DU Yan
. Power spectrum analysis of Indonesian Throughflow based on INSTANT data[J]. Journal of Tropical Oceanography, 2011
, 30(6)
: 1
-9
.
DOI: 10.11978/j.issn.1009-5470.2011.06.001
[1] WIJFFELS S, SPRINTALL J, FIEUX M, et al. The JADE and WOCE I10/IR6 Throughflow section in the southeast Indian Ocean. Part 1: Water mass distribution and variability[J]. Deep-Sea Res Ⅱ. 2002, 49: 1341-1362.
[2] GODFREY J S. The effect of the Indonesian Throughflow on ocean circulation and heat exchange with the atmosphere: A review[J]. J Geophys Res, 1996, 101: 12217– 12237
[3] WYRTKI K. Physical oceanography of the Southeast Asian waters[G]// NAGA Report Volume 2. Scripps Institution of Oceanography, 1961: 195.
[4] QIU B, MAO M, KASHINO Y. Intraseasonal variability in the Indo-Pacific Throughflow and the regions surrounding the Indonesian Seas[J]. J Phys Oceanogr, 1999, 29: 1599-1618.
[5] WIJFFELS S, MEYERS G. An intersection of oceanic wave guides: Variability in the Indonesian throughflow region[J]. J Phys Oceanogr, 2004, 34: 1232-1253.
[6] SUSANTO R W, GORDON A L, SPRINTALL J, et al. Intraseasonal variability and tides in Makassar Strait[J]. Geophys Res Lett, 2000, 27(10): 1499-1502.
[7] SPRINTALL J, GORDON A L, MURTUGUDDE L, et al. A semiannual Indian Ocean forced Kelvin wave observed in the Indonesian seas in May 1997[J]. J Geophys Res, 2000, 105 (C7): 17217-17230.
[8] EGBERT G D, RAY R D. Estimates of M2 tidal energy dissipation from TOPEX/Poseidon altimeter data[J]. J Geophys Res, 2001, 106: 22475-22502.
[9] HATAYAMA T, AWAJI T, AKITOMO K. Tidal currents in the Indonesian Seas and their effect on transport and mixing[J]. J Geophys Res, 1996, 101: 12353-12373.
[10] GORDON A, WIJFFELS S, SPRINTALL J, et al. The Indonesian Throughflow, 3-year INSTANT composite view[M]. CSIRO Marine and Atmospheric Research, 2008: 16.
[11] VINAYACHANDRAN P N, KURIAN J, NEEMA C P. Indian Ocean response to anomalous conditions in 2006[J]. Geophys Res Lett, 2007, 34(L15602). doi:10.1029/ 2007GL030194.
[12] SPRINTALL J, WIJFFELS S E, MOLCARD R, et al. Direct estimates of the Indonesian Throughflow entering the Indian Ocean: 2004–2006[J]. J Geophys Res, 2009, 114, C07001, doi:10.1029/2008JC005257.
[13] MURRAY S P, ARIEF D. Throughflow into the Indian Ocean through the Lombok Strait, January 1985 – January 1986[J]. Nature, 1988, 333: 444-447.
[14] MOLCARD R M, FIEUX M, SYAMSUDIN F. The Throughflow within Ombai Strait[J]. Deep-Sea Res, 2001, 48: 1237-1253.
[15] CRESSWELL G, FRISCHE A, PETERSON J, et al. Circulation in the Timor Sea[J]. J Geophys Res, 1993, 98: 14379-14389.
[16] MASUMOTO Y, YAMAGATA T. Simulated seasonal circulation in the Indonesian seas[J]. J Geophys Res, 1993, 98: 12501-12509.
[17] CLARKE A J, LIU X. Observations and dynamics of semiannual and annual sea levels near the eastern equatorial Indian Ocean boundary[J]. J Phys Oceanogr, 1993, 23: 386-399.
[18] MOLCARD R, FIEUX M, ILAHUDE A G. The Indo–Pacific throughflow in the Timor Passage[J]. J Geophys Res, 1996, 101: 12411-12420.
[19] MCCLEAN J L, IVANOVA D P, SPRINTALL J. Remote origins of interannual variability in the Indonesian Throughflow region from data and a global Parallel Ocean Program simulation[J]. J Geophys Res, 2005, 110, C10013, doi:10.1029/2004JC002477.
[20] ARIEF D, MURRAY S P. Low-frequency fluctuations in the Indonesian Throughflow through Lombok Strait[J]. J Geophys Res, 1996, 101: 12455-12464.
[21] SYAMSUDIN F, KANEKO A, HAIDVOGEL D. Numerical and observational estimates of Indian Ocean Kelvin wave intrusion into Lombok Strait[J]. Geophys Res Lett, 2004, 31 (L24307). doi:10.1029/2004GL021227.
[22] SCHILLER A, WIJFFELS SE, SPRINTALL J, et al. Pathways of intraseasonal variability in the Indonesian Throughflow region[J]. Dyn Atmos Oceans, 2010, 50(2): 174-200.
[23] SYAMSUDIN F, VAN AKEN H F, KANEKO A. Annual variation of the southern boundary current in the Banda Sea[J]. Dyn Atmos Oceans, 2010, 50(2): 129-139. .
[24] DU Y, QU T. Three inflow pathways of the Indonesian throughflow as seen from the Simple Ocean Data Assimilation[J]. Dyn Atmos Oceans, 2010, 50(2): 233-256.
[25] ROBERTSON R. Tidal Currents and Mixing at the INSTANT Mooring Locations[J]. Dyn Atmos Oceans, 2010, 50(2): 331-373.
