Ocean Observing System (OOS) Programme: Equatorial deep-sea current meter moorings 

The Department of Ocean Development (DOD), Government of India, initiated the Ocean Observing System (OOS) programme in 1997 for long-term current measurements in the equatorial Indian Ocean through the Indian National Centre for Ocean Information System (INCOIS), Hyderabad. Under the OOS, 3 locations were selected along the equator for deploying the current meter moorings at 93E, 83E and 76E (Fig 1). The responsibility of executing the project Long-term measurements of the currents along the equator through current meter moorings was given to the National Institute of Oceanography (NIO), Goa. This project was implemented at NIO in 2002 after developing a suitable mooring design and procuring the current meters and relevant hardware.  The mooring was designed with 6 Recording Current Meters (RCMs) at 100 m, 300 m, 500 m, 1000 m, 2000 m and 4000 m. The first deep-sea current meter mooring was deployed successfully in February 2000 at equator, 93E onboard ORV Sagar Kanya. This mooring was successfully recovered in December 2000 and data were obtained from all the RCMs. The mooring was redeployed and the new second mooring was deployed at equator, 83E in December 2000. In March 2002, these two moorings were recovered and data were obtained. While redeploying these moorings at the same locations, a new third mooring was deployed at equator, 76E. In October 2003, all the three moorings were recovered and redeployed for one more year, but the mooring at 76E was shifted to 77E (Fig 1). In October 2004, all the three moorings were recovered and deployed for another year. One Up-looking ADCP was placed at 100 m on top of each mooring. The recovery of these moorings has been rescheduled to March/April 2006 due to non-availability of the vessel ORV Sagar Kanya in November/December 2005. This project will be continued till March 2007 with funding from DOD, and might be extended possibly for another 5 years through 2012. Though there is no human-vandalism for the moorings, we often encounter heaps of Tuna-fishing nets around the top current meter, particularly at 93E mooring location. The time-series currents data were submitted to the INCOIS, Hyderabad and will be placed on the Websites of NIO and INCOIS. 

Fig 1: Map showing the locations of the OOS Equatorial deep sea current meter moorings.

Table 1. Status of Deep-sea Current meter moorings along the equator under the Ocean Observing System (OOS) Program since February 2000

The moorings at 93E and 83E and 77E were deployed for another year.

Table 2. Mean depths of RCMs in the deep-sea current meter moorings of duration given in the above Table (1)

Table 3. Data filenames at the depths in each mooring as per Tables 1 & 2.

Legend to the data file: 

You may like to download any of the above data files and use for research purpose. Please do acknowledge Department of Ocean Development, Govt of India and the NIO mooring team for making the data available to you. Also please do cite following references where the work has already been published:

Sengupta, D.; Senan, R.; Murty, V.S.N.; Fernando, V. A biweekly mode in the equatorial Indian Ocean. J. Geophys. Res. (C: Oceans): 109; 2004; 12 pp.

Murty, V.S.N.; Suryanarayana, A.; Sarma, M.S.S.; Tilvi, V.; Fernando, V.; Nampoothiri, G.; Sardar, A.; Gracias, D.; Khalap, S. First results of Indian - Current meter moorings along The equator: Vertical current structure variability at equator, 93 degrees E during February-December, 2000. Proceedings of The Sixth Pan Ocean Remote Sensing Conference (PORSEC) Bali, 3-6 September 2002: Remote sensing and ocean science for marine resources exploration and environment. Vol. 1. eds. by: Pasaribu, B.P.; Kaswadji, R.; Nurjaya, I.W.; Gaol, J.L.(6. Pan Ocean Remote Sensing Conf. (PORSEC); Bali; 3-6 Sep 2002). PORSEC 2002 Secretariat; Bogor; Indonesia; 2002; 25-28.

Project Team:

Dr.VSN Murty - Principal Investigator
Dr.A.Suryanarayana 
Mr.M.S.S.Sarma
Mr.Vijayan Fernando
Mr.Areef Sardar
Mr.D.Gracias
Mr.Sadhashiv Khalap
Mr.Yogesh Agarvadekar.V
Mr.Ansalem Almeida
Mr.S.Murali Krishna