139736eo.pdf (20MB) - Japan Oceanographic Data Center

In the Arabian Sea dissolved oxygen concentrations generally decline rapidly with depth,particularly north of 20"N; the dissolved oxygen content of the water in thermocline decreases attemperatures of 26"-27"C, signifyin that the oxygen demands exceed the supply at 100 m. In theeddy field oxygen values of 3 ml 1- K at 100 m indicate that water trapped in the eddy field is welloxygenated. Even at the thermocline, where water temperatures are 26-27'C, oxygen concentrationsare 3.5 ml l-1 , possibly because of the sinking of surface water as indicated by the salinity distribution(Fig. 4).The whole eddy field is rich in both nutrients and dissolved oxygen, which would infer anincrease in local biological productivity. Preliminary observations indicate that the zoo lankton isindeed rich, and standing crops (measured by displacement volume) of 0.29 - 0.72 m m- P have beenobserved. However, more detailed studies are required to correlate the intensity of eddy withproductivity, and in turn to SW monsoon intensity.CONCLUSIONIt is possible to predict monsoon intensity in advance, from few weeks to months, andpossibly even several years based on various physical oceanographic parameters and processesresulting from ocean and atmospheric interaction. However, detailed and systematic studies arerequired to understand scientific phenomena and refine the forecast.REFERENCESBRUCE, J.G. (198 1). Variation in the thermal structure and wind field occurring in the WesternIndian Ocean during the monsoons. Naval Oceanographic Office TR-272, 171 p.(unpublished manu script).CAGLE, B.T. and WHRITNER, R. (1981). Arabian Sea project of 1980 - Compositers of infraredimages. Office of Naval Research ONRWEST 81-5, 16 p. 1030 East Green Street,Pasadena, CA 91 106 USA.MEERA PATHMARAJAH (1982). Pollution and the marine environment in the Indian Ocean.UNEP Regional Seas Reports and Studies No. 13, UNEP 253 p.MOLINARI, R.L. (1983). Somali basin response to the monsoons and feedback effects on theatmosphere. CCCO Panel on Indian Ocean Climate Studies, Report of the First Session,21-23 March 1983, Paris.PANT, G.B. and PARTHASARATHY (1981). Some aspects of an association between the SouthernOscillation and Indian summer monsoon. Arch. Met. Geophy. Ser. B, 29,245-252.PHILANDER, S.G.H. (1983). El-Niiio Southern Oscillation phenomena. Nature, 302,295-301.Q'UTRAISElEE, G.S. (1984). Circulation in the North Arabian Sea at Murray Ridge during SW.monsoon. Deep-sea Research, 31,651-664.QURAISHEE, G.S. (1985). Dynamic heights and Ocean thermal structure as possible signals forforecasting variation in the SW monsoon. CCCO Panel on Indian Ocean Climate Studies,Report of the Second Session, 28-31 January 1985, New Delhi.SHUKLA, J. (1983). Arabian Sea surface temperature anomaly and Indian summer monsoon rainfall.CCCO Panel on Indian Ocean Climate Studies, Report of the First Session, 21-23 March1983, Paris.231