5.1 Ocean Observing Systems

This programme is designed to acquire in-situ surface, meteorological and oceanographic data on real- time basis from the seas around India. The parameters measured under this programme are surface wind, waves, atmospheric temperature and pressure, sea surface temperature, salinity, dissolved oxygen, hydrocarbons, nutrients, radio-activity, sea-level, etc. The state-of-the-art instruments like moored data buoys, drifting buoys, XBTs, current meter arrays and tide gauges are deployed for measurements. In addition, validation of the satellite data would also be undertaken using the sea truth data generated under this programme.

5.1.1 National Data Buoy Programme

Under the National Data Buoy Programme (NDBP) being implemented at NIOT twelve data buoys have been deployed in Indian seas. These data buoys have sensors to measure wind speed and direction, air pressure, air temperature, sea surface temperature, current speed and current direction and wave parameters. The buoys are equipped with Global Positioning System, beacon light and satellite transceiver. Few of these buoys are fitted with sensors to measure radioactivity, turbidity, chlorophyll, hydrocarbons, and dissolved oxygen.

Daily data at 3GMT are being sent to India Meteorological Department (IMD) and Coast Guard. Monthly data are being disseminated to Naval Hydrographic Office, Ports (wherever the buoys are deployed). Data is also being supplied to National Institute of Oceanography, Centre for Atmospheric and Oceanic Science, IISC and other Oceanographic, Research and Academic institutions against their specific project requirements. Buoys data have played an important role in weather prediction by IMD, particularly during the recent depression and cyclonic storm in Indian seas. In order to ensure quality data acquisition from the sensors, NDBP carries out regular planned maintenance as well as urgent maintenance as and when warranted by the data buoys. During this year eight re-deployment, eight retrieval and eleven maintenance operations have been carried out.

By operationalising the National Data Buoy programme, India has enhanced its capacity in ocean observation system and has received acclaimation from the global oceanographic community.

5.1.2 Drifting Buoys and other Observing Systems

To augment the ocean observations, the department is also implementing a programme for deployment of other observing systems through the National Institute of Oceanography, Goa . About 48 drifting buoys will be deployed at periodical intervals over the 9th Plan period. The buoys so deployed will generate in-situ data, as well as validate the satellite data.

During the year, fifteen drifting buoys with sensors for Sea Surface Temperature and barometric pressure, were deployed in the Indian ocean. With this the total number of drifting buoys deployed has gone up to twenty-four during the last two years. Four of these buoys were equipped with additional sensors for sea surface temperature, atmospheric pressure and temperature, wind speed and direction. The data are being transmitted via ARGOS-Satellite and made available to the Indian Meteorological Department and National Centre for Medium Range Weather Forecast (NCMRWF) on real-time basis.

5.1.3 Sea Level Observation

The Sea Level Monitoring project envisages assessment of variations in the sea level due to climatic and other factors and impact of such variations on the Indian coastal belt. Under this project, 8 modern tide gauge stations have been established at Mumbai, Porbander, Goa, Kochi, Chennai, Visakhapatnam, Paradip and Kavaratti and two more tide gauges will be deployed at Machilipatnam and Tuticorin. National Tide Data Centre at Survey of India, Dehradun has analysed the data generated and developed a numerical model to simulate ocean circulation in the Northern Indian Ocean.