The objective of OOS programme is to acquire in-situ oceanographic and surface meteorological parameters on real-time basis from the seas around India. The parameters being measured under the programme include surface winds, waves, atmospheric pressure, temperature, sea surface temperature, salinity, temperature profiles, dissolved oxygen, hydrocarbons, nutrients, radio-activity, sea-level, etc. The instruments deployed for measurements of these parameters are moored data buoys, drifting buoys, expendable bathythermographs (XBT), current meter arrays and tide gauges. Validation of the satellite sensors would also be undertaken using the sea truth data generated under this programme. The OOS project consists of three sub-projects viz., National Data Buoy Programme, Sea Level observation and Drifting buoy and other Observing systems.

6.1.1 National Data Buoy Programme

The National Data Buoy Programme, being implemented by National Institute of Ocean Technology (NIOT), Chennai, envisages assembly, deployment, operation and maintenance of state-of-the-art technology data buoys. Under this programme, a set of 12 met-ocean data buoys have been deployed in the coastal and offshore of India for acquiring, surface meteorological and upper ocean parameters. The buoys are equipped with state-of-the-art sensors for accurate measurement of winds, waves, currents, atmospheric pressure, atmospheric temperature, sea surface temperature, dissolved oxygen, chlorophyll, radioactivity, hydrocarbon and turbidity.

A shore station was commissioned at NIOT for retrieval, processing, analysis and storage of the data from the buoys. The data buoys were deployed, using department’s research vessel ORV Sagar Kanya. The transmission of data between the buoys and shore station is through a two-way communication system of INMARSAT-C satellite. The data being disseminated daily at 3 GMT to India Meteorological Department and Coast Guard has contributed in the forecast of cyclones in the Bay of Bengal and the Arabian Sea.

During the year 2 shallow water buoys were deployed one each at Pipavav and New Mangalore port for collection of met-ocean parameters required for developmental activities of these ports. Three cruises on-board Sagar Kanya were conducted for 7 retrieval and 10 deployment operations towards maintenance of buoys deployed in the Bay of Bengal in the Arabian Sea. Tamper proof frame on 2 Wavescan deep water buoys to prevent vandalism was carried out. Some of the meteorological parameters such as wind speed, direction, atmospheric pressure, temperature and sea surface temperature are made available on-line through Global Telecommunication System (GTS).

NDBP made special efforts to support the BOBMEX cruise to collect atmospheric and oceanographic data by deploying buoys, which have provided real time data for BOBMEX as well for validation of IRS-P4 data.

6.1.2 Drifting Buoys and Other Observing Systems

The programme being implemented through NIO, Goa envisages deployment of drifting buoys, Expendible Bathythermographs (XBTs), and current meter arrays, for augmentation of in-situ oceanographic data. About 48 drifting buoys, 3 current meter arrays and 900 XBTs would be deployed under this programme during the IX plan period. The data under this programme would serve not only for improvement of understanding on the oceanographic processes in the Indian seas as well as validation of satellite data.

Nineteen low cost drifters and two multi-parameter drifters were deployed in the Northern Indian Ocean during the year for improved understanding of the surface circulation of the Bay of Bengal and the Arabian Sea. The low cost drifters are equipped with barometer and temperature sensors for measurement of atmospheric pressure and sea surface temperature (SST), while the multi-parameter buoys will also measure wind speed and direction, atmospheric temperature and pressure. One deep sea current meter array along the equator at 93° E for measurement of current speed and direction would be fabricated and deployed during the year. About 300 XBT probes in the identified shipping routes for collection of temperature profiles up to 750m depth to study the upper-ocean thermal structure of the Northern Indian Ocean have been carried out. The drifting buoy data are being transmitted via ARGOS-Satellite, whereas the XBT data are being processed and archived at NIO for a variety of uses in the field of ocean research and developmental activities. Three special sea truth campaigns for validation of OCEANSAT sensors were conducted.

6.1.3 Sea Level Observation

Under the project 10 modern tide gauges stations were established at Mumbai, Porbunder, Goa, Kochi, Chennai, Visakhapatnam, Paradip, Kavaratti, Machlipatnam and Tuticorin for systematic and accurate monitoring the tidal level to derive long term variations in the mean sea levels. The data from these tide gauges are collected regularly and sent to the 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. Continuation of operation and maintenance of 8 tide gauge stations already set-up and installation of tide gauge cabins at 2 other places were carried out during the year.