Surface circulation and upwelling patterns around Sri Lanka

Biogeosciences - Tập 11 Số 20 - Trang 5909-5930
Asha de Vos1,2,3, Charitha Pattiaratchi1, Sarath Wijeratne1
1School of Civil, Environmental and Mining Engineering & The UWA Oceans Institute, University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
2The Centre for Ocean Health, The University of California Santa Cruz, CA 95060, USA
3The Sri Lankan Blue Whale Project, 131 W.A.D. Ramanayake Mawatha, Colombo 2, Sri Lanka

Tóm tắt

Abstract. Sri Lanka occupies a unique location within the equatorial belt in the northern Indian Ocean, with the Arabian Sea on its western side and the Bay of Bengal on its eastern side, and experiences bi-annually reversing monsoon winds. Aggregations of blue whale (Balaenoptera musculus) have been observed along the southern coast of Sri Lanka during the northeast (NE) monsoon, when satellite imagery indicates lower productivity in the surface waters. This study explored elements of the dynamics of the surface circulation and coastal upwelling in the waters around Sri Lanka using satellite imagery and numerical simulations using the Regional Ocean Modelling System (ROMS). The model was run for 3 years to examine the seasonal and shorter-term (~10 days) variability. The results reproduced correctly the reversing current system, between the Equator and Sri Lanka, in response to the changing wind field: the eastward flowing Southwest Monsoon Current (SMC) during the southwest (SW) monsoon transporting 11.5 Sv (mean over 2010–2012) and the westward flowing Northeast Monsoon Current (NMC) transporting 9.6 Sv during the NE monsoon, respectively. A recirculation feature located to the east of Sri Lanka during the SW monsoon, the Sri Lanka Dome, is shown to result from the interaction between the SMC and the island of Sri Lanka. Along the eastern and western coasts, during both monsoon periods, flow is southward converging along the southern coast. During the SW monsoon, the island deflects the eastward flowing SMC southward, whilst along the eastern coast, the southward flow results from the Sri Lanka Dome recirculation. The major upwelling region, during both monsoon periods, is located along the southern coast, resulting from southward flow converging along the southern coast and subsequent divergence associated with the offshore transport of water. Higher surface chlorophyll concentrations were observed during the SW monsoon. The location of the flow convergence and hence the upwelling centre was dependent on the relative strengths of wind-driven flow along the eastern and western coasts: during the SW (NE) monsoon, the flow along the western (eastern) coast was stronger, migrating the upwelling centre to the east (west).

Từ khóa


Tài liệu tham khảo

Alaee, J. M., Ivey, G., and Pattiaratchi, C.: Secondary circulation induced by flow curvature and Coriolis effects around headlands and islands, Ocean Dynam., 54, 27–38, 2004.

Alaee, J. M., Pattiaratchi, C. B., and Ivey, G. N.: Numerical simulation of the summer wake of Rottenest Island, Western Australia, Dynam. Atmos. Oc., 43, 171–198, 2007.

Barkley, R. A.: Johnston Atoll's wake, J. Mar. Res., 30, 210–216, 1972.

Barton, E. D., Basterretxea, G., Flament, P., Mitchelson-Jacob, E. G., Jones, B., Arístegui, J., and Herrera, L.: region of Gran Canaria, J. Geophys. Res., 105, 173–117, 2000

Bleck, R.: An oceanic general circulation model framed in hybrid isopycnic-cartesian coordinates, Oc. Modell., 4, 55–88, 2002.

Bowman, M. J., Dietrich, D. E., and Lin, C. A.: Observations and modelling of mesoscale ocean circulation near a small island, in: Small Islands: Marine Science and Sustainable Development, Coastal and Estuarine Studies, edited by: Maul, G., American Geophysical Union, Washington DC, 18–35, 1996.

Bucciarelli, E., Blain, S. P., and Tréguer, P.: Iron and manganese in the wake of the Kerguelen Islands (Southern Ocean), Mar. Chem., 73, 21–36, 2001.

Caldeira, R. M. A., Groom, S., Miller, P., Pilgrim, D., and Nezlin, N. P.: Sea-surface signatures of the island mass effect phenomena around Madeira Island, Northeast Atlantic, Remote Sens. Environ., 80, 336–360, 2002.

Chang, Y.-L., Oey, L.-Y., Wu, C.-R., and Lu, H.-F.: Why are there upwellings on the northern shelf of Taiwan under northeasterly winds?, J. Phys. Oceanogr., 40, 1405–1417, 2010.

Cowen, R. K. and Castro, L. R.: Relation of coral reef fish larval distributions to island scale circulation around Barbados, West Indies, Bull. Mar. Sci., 54, 228–244, 1994.

de Vos, A., Pattiaratchi, C. B., and Harcourt, R. G.: Inter-annual variability in blue whale distribution off southern Sri Lanka between 2011 and 2012, J. Mar. Sci. Engin., 2, 534–550, 2014.

Di Lorenzo, E., Moore, A. M., Arango, H. G., Cornuelle, B. D., Miller, A. J., Powell, B., Chua, B. S., and Bennett, A. F.: Weak and strong constraint data assimilation in the inverse Regional Ocean Modeling System (ROMS): Development and application for a baroclinic coastal upwelling system, Ocean Model. Online, 16, 160–187, 2007.

Dong, C. and McWilliams, J. C.: A numberical study of island wakes in the Southern California Bight, Cont. Shelf Res., 27, 1233–1248, 2007.

Dong, C., Idica, E. Y., and McWilliams, J. C.: Circulation and multiple-scale variabiltiy in the Southern California Bight, Prog. Oceanogr., 82, 168–190, 2009.

Doty, M. S. and Oguri, M.: The island mass effect, J. Conserv., 22, 33–37, 1956.

Durand, F., Shankar, D., Birol, F., and Shenoi S. S. C.: Spatiotemporal structure of the East India Coastal Current from satellite altimetry, J. Geophys. Res. (oceans), 114, C02013, https://doi.org/10.1029/2008JC004807, 2009.

Hafner, J. and Xie, S.-P.: Far-field simulation of the Hawaiian wake: Sea surface temperature and orographic effects, J. Atmos. Sci., 60, 3021–3032, 2003.

Haidvogel, D. B., Arango, H., Budgell, W. P., Cornuelle, B. D., Curchitser, E., Di Lorenzo, E., Fennel, K., Geyer, W. R., Hermann, A. J., Lanerolle, L., Levin, J., McWilliams, J. C., Miller, A. J., Moore, A. M., Powell, T. M., Shchepetkin, A. F., Sherwood, C. R., Signell, R. P., Warner, J. C., and Wilkin, J.: Ocean forecasting in terrain-following coordinates: Formulation and skill assessment of the Regional Ocean Modeling System, J. Computat. Phys., 227, 3595–3624, 2008.

Heywood, K. J., Barton, E. D., and Simpson, J. H.: The effects of flow disturbance by an oceanic island, J. Mar. Res., 48, 55–73, 1990.

Jensen, T. G.: Arabian Sea and Bay of Bengal exchange of salt and tracers in an ocean model, Geophys. Res. Lett., 28, 3967–3970, 2001.

Kabanova, J. G.: Primary production of the northern part of the Indian Ocean, Oceanology, 8, 214–225, 1968.

Legeckis, R.: Satellite observations of a western boundary current in the Bay of Bengal, J. Geophys. Res. (Oceans), 92, 12974–12978, 1987.

Levitus, S., Burgett, R., and Boyer, T. P.: World ocean atlas 1994, NOAA Atlas NESDIS 3, US Government Printing Office, Washington, DC, 1994.

Luis, A. J. and Kawamura, H.: Wintertime wind forcing and sea surface cooling near the south India tip observed using NSCAT and AVHRR, Remote Sens. Environ., 73, 55–64, 2000.

Magnell, B. A., Bray, M. A., Winant, C. D., Greengrove, C. L., Largier, J. L., Borchardt, F., Bernstein, R. L., B., and Dorman, C. E.: Convergent shelf flow at Cape Mendocino, Oceanography, 3, 4–11, 1990.

Marchesiello, P., McWilliams, J. C., and Shchepetkin, A.: Open boundary conditions for long-term integration of regional oceanic models, Ocean Model. Online, 3, 1–20, 2001.

Marchesiello, P., McWilliams, J. C., and Shchepetkin, A.: Equilibrium structure and dynamics of the California current system, J. Phys. Oceanogr., 33, 753–783, 2003.

McCreary Jr., J. P., Murtugudde, R., Vialard, J., Vinayachandran, P. N., Wiggert, J. D., Hood, R. R., Shankar, D., and Shetye, S.: Biophysical processes in the Indian Ocean, Geophys. Monogr. Ser., 185, 9–32, 2009.

Michisaki, R. P., Chavez, F. P., Friederich, G. E., and Kelley, M.: Evolution of chemical and biological properties in the Arabian Sea and Indian Ocean during 1995 from automated surface mapping, American Geophysical Union Ocean Sciences meeting, San Diego, 1996.

Palacios, D. M.: Factors influencing the island-mass effect of the Galápagos Archipelago, Geophys. Res. Lett., 29, 2134, https://doi.org/10.1029/2002gl016232, 2002.

Pattiaratchi, C., James, A., and Collins, M.: Island wakes and headland eddies: A comparison between remotely sensed data and laboratory experiments, J. Geophys. Res. (Oceans), 92, 783–794, 1987.

Pawlowicz, R., Beardsley, B., and Lentz, S.: Classical tidal harmonic analysis including error estimates in MATLAB using T_TIDE, Comput. Geosci., 28, 929–937, 2002.

Saetersdal, G., Bianchi, G., Stomme, T., and Venema, S. C.: The Dr. Fridtjof Nansen Programme 1975-1993: Investigations of fishery resources in developing countries. History of the programme and review of results, Food and Agriculture Organisation of the United Nations, Rome, 434 pp., 1999.

Sahini, A.: The structure, sedimentation and evolution of Indian continental margins, in: The ocean basins and margins: The Indian Ocean, edited by: Nairn, E. M. and Stehli, F. G., Plenum Press, New York, 353–398, 1982.

Schott, F., Reppin, J., Fischer, J., and Quadfasel, D.: Currents and transports of the monsoon current south of Sri Lanka, J. Geophys. Res.-Oceans, 99, 25127–25141, 1994.

Schott, F. A. and McCreary, Jr., J. P.: The monsoon circulation of the Indian Ocean, Prog. Oceanogr., 51, 1–123, 2001.

Shankar, D. and Shetye, S. R.: On the dynamics of the Lakshadweep high and low in the southeastern Arabian Sea, J. Geophys. Res.-Oceans, 102, 12551–12562, 1997.

Shankar, D., Vinayachandran, P. N., and Unnikrishnan, A. S.: The monsoon currents in the north Indian Ocean, Prog. Oceanogr., 52, 63–120, 2002.

Shchepetkin, A. F. and McWilliams, J. C.: The regional oceanic modeling system (ROMS): a split-explicit, free-surface, topography-following-coordinate oceanic model, Ocean Model. Online, 9, 347–404, 2005.

Shepard, E. P.: Submarine geology, Harper and Row Publishers, New York, 1963.

Song, Y. and Haidvogel, D.: A semi-implicit ocean circulation model using a generalized topography-following coordinate system, J. Computat. Phys., 115, 228–244, 1994.

Sreenivas, P., Gnanaseelan, C., and Prasad, K. V. S. R.: Influence of El Niño and Indian Ocean Dipole on sea level variability in the Bay of Bengal, Glob. Planet. Change, 80/81, 215–225, 2012.

Swan, B.: An Introduction to the Coastal Geomorphology of Sri Lanka, National Museums of Sri Lanka, Colombo, 1983.

Tomczak, M.: Island wakes in deep and shallow water, J. Geophys. Res., 93, 5153–5154, 1988.

Tomczak, M. and Godfrey, J. S.: Regional oceanography: An introduction, 2 Edn., Pergamon, 2003.

Varkey, M. J., Murty, V. S. N., and Suryanarayana, A.: Physical oceanography of the Bay of Bengal and Andaman Sea, in: Oceanogr. Mar. Biol. Annu. Rev., edited by: Ansell, A. D., Gibson, R. N., and Barnes, M., CRC Press, 1–70, 1996.

Vinayachandran, P. N. and Yamagata, T.: Monsoon response of the sea around Sri Lanka: Generation of thermal domes and anticyclonic vortices, J. Phys. Oceanogr., 28, 1946–1960, 1998.

Vinayachandran, P. N., Masumoto, Y., Mikawa, T., and Yamagata, T.: Intrusion of the southwest monsoon current into the Bay of Bengal, J. Geophys. Res.-Oceans, 104, 11077–11085, 1999.

Vinayachandran, P. N., Chauhan, P., Mohan, M., and Nayak, S.: Biological response of the sea around Sri Lanka to summer monsoon, Geophys. Res. Lett., 31, L01302, https://doi.org/10.1029/2003GL018533, 2004.

Wijeratne, E. M. S.: Tidal characteristics and modelling of tidal wave propagation in shallow lagoons of Sri Lanka, Ph.D., Gothenburg University, Gothenburg, 2003.

Wijeratne, E. M. S., Woodworth, P. L., and Stepanov, V. N.: The seasonal cycle of sea level in Sri Lanka and southern India, West Indian Ocean J. Mar. Sci., 7, 29–43, 2008.

Wijeyananda, N. P.: Maritime zones, in: Arjuna's atlas of Sri Lanka, edited by: Somasekaram, T., Perera, M., de Silva, M. B. G., and Godellawatta, H., Arjuna Consulting Company Limited, Colombo, 5–7, 1997.

Wolanski, E., Imberger, J., and Heron, M. L.: Island wakes in shallow coastal waters, J. Geophys. Res., 89, 553–569, 1984.

Wyrtiki, K.: Physical oceanography of the Indian Ocean, in: The Biology of the Indian Ocean, edited by: Zeitzschel, B. and Gerlach, S. A., Springer-Verlag, Heidelberg, 1973.

Xu, J., Lowe, R. J., Ivey, G. N., Pattiaratchi, C. B., Jones, N. L., and Brinkman, R.: Dynamics of the summer shelf circulation and transient upwelling off Ningaloo Reef, Western Australia, J. Geophys. Res.-Oceans, 118, 1099–1125, 2013.

Yapa, K. K. A. S.: Upwelling phenomena in the southern coastal waters of Sri Lanka during southwest monsoon period as seen from MODIS, Sri Lanka J. Phys., 10, 7–15, 2009.

Thông tin
Thông tin xuất bản

Biogeosciences

Tập 11 Số 20

5909-5930

Thông tin tác giả