6.1 Ocean Observing System (OOS)


6.1.1 National Data Buoy Programme

The real time in-situ observation of oceanographic and meteorological parameters over Indian seas is vital to improve the predictive capability of short term and long term climatic changes as well to increase the understanding of ocean dynamics and air-sea interaction process in this region. A moored met-ocean data buoy off west coast

Keeping this in view, Department of Ocean Development (DOD) established a National Data Buoy Programme (NDBP) at National Institute of Ocean Technology (NIOT), Chennai with Norwegian Agency for Development Cooperation (NORAD) assistance. Under this programme, 12 moored data buoys were deployed in Indian seas both in shallow and deep waters during 1997-98 to cater the needs of real time users like IMD and Coast Guard as well the data supply to a variety of applications like Port activities, Harbour/offshore-structure development, Satellite data validation, Environmental monitoring, Oceanographic/Climate studies etc.

NDBP carried out regular and emergency maintenance of data buoys whenever required. During the year under report, NDBP has accomplished 18 deployments, 9 retrievals and 1 in situ servicing of buoys. The buoy features have been improved to be tamper proof.

NORAD final annual meeting on NDBP was held on 16th October 2000. The Royal Norwegian Embassy expressed happiness of the Norwegian Government on the successful progress of NDBP. This project is an example for demonstrating the success of developmental co-operation between Governments of Norway and India. NORAD has released its full NOK 27 million aid for this programme to Government of India.



NDBP supported IMD by providing data round the clock during the periods (17-18 October & 27-28 November, 2000) of depression, which formed in the Bay of Bengal. IMD has acknowledged the importance of buoy data in predicting the movement of the cyclone during the depression in bay.

6.1.2 Drifting Buoy Programme

The programme envisages deployment of a suite of drifting buoys, expendable bathythermographs (XBTs) and current meter arrays for augmentation of in-situ oceanographic measurements. During the IX plan period, about 50 drifting buoys, 3 current meter arrays, and 900 XBTs would be deployed under the programme. The data from the buoys is transmitted online using CLS-ARGOS satellite primarily for validation of satellite sensors besides its contribution towards understanding the oceanographic processes around India.

During the year a set of 5 drifting buoys have been deployed and 5 more are planned to be deployed soon in the tropical Indian Ocean for collection of SST and atmospheric pressure. The data is being transmitted to GTS to various users on near real time. Experiments for applying correction for the slippage due to winds have also been conducted. Upgradation of data archives for the Indian Ocean (60deg S to 25deg N) was also carried out using the data collected from the buoys deployed over a period of 25 years (1976 to 1999). Indigenous production of two drifters was carried out. Using SST data from the drifting buoy data archives of monthly climatology at a spatial resolution of 2deg latitude x 2deg longitude would be prepared.

6.1.3 Sea Level Observation

Under the project 10 modern tide gauge stations were established at Mumbai, Porbandar, Goa, Kochi, Chennai, Visakhapatnam, Paradip, Kavaratti, Machlipatnam and Tuticorin for systematic and accurate monitoring of the tide levels to assess the long-term variations in the mean sea levels. The data from these tide gauges are collected regularly and archived at National Tide Data Centre at Survey of India, Dehradun.

Based on the sea level data collected along the Indian coast, a numerical model has been constructed to simulate circulation in the Northern Indian Ocean.