6. OCEAN OBSERVATION & INFORMATION SERVICES (OOIS)

 

Considering the importance of information and knowledge of the seas around India, the Department formulated an integrated programme called “Ocean Observation and Information Services (OOIS)” for implementation during the 9th Plan.  The OOIS is aimed at (i) development of a wide range ocean-atmospheric & coastal models, (ii) generation of algorithms for retrieval of satellite parameters, (iii) augmentation of ocean observations including in-situ and satellite measurements, and (iv) operationalisation of ocean advisory services.  The OOIS consists of four major components viz., Ocean Observing System, Ocean Information Services, Ocean Modelling & Dynamics and Satellite Coastal Oceanographic Research. The details of achievement under each component of OOIS programme are as follows.

 

6.1  Ocean Observing System (OOS)

Ocean observing system is designed for generation of systematic, scientific and long-term data of oceanographic and meteorological parameters by deployment of state-of-the-art technology instruments i.e., Met-Ocean moored buoys, drifting buoys, XBTs, Current meter array and tide-gauges. During the IX plan, the Department targeted to establish a comprehensive Ocean Observing System (OOS) programme for generation of surface oceanographic and meteorological data.

 

6.1.1  National Data Buoy Programme (NDBP)

Under this programme, being implemented by the National Institute of Ocean Technology (NIOT), 12 moored data buoys were deployed in the Indian seas both in shallow and deep waters to cater to the needs of real time data. The main end users are IMD, Coast Guard, National Hydrographic Department and supply of data to a variety of applications like port activities, harbour/offshore-structure development, satellite data validation, environmental monitoring, climate studies, etc. NDBP carries out routine and emergency maintenance of data buoys.  During this period NDBP accomplished 10 deployments and 9 retrievals of buoys in the Indian seas.

 

By providing tamper proof arrangements in the buoys, the incidence of vandalism of the buoys was substantially reduced.

 

6.1.2 Indigenisation of data buoy production, operation and management

 

Indigenisation of 12 data buoy production, operation and management is in progress. Under this activity, the Central Processing Unit has been indigenised jointly by NIOT and M/s. Inventa Informatics Private Limited, Chennai. The unit underwent successful environmental testing at Electronic Testing and Development Corporation, Chennai and functional testing has been carried out at NIOT. The unit has been named as “Dolphin”

 

                                                               

Indigenously built data acquisition and processing system for data buoys

 

With the close co-operation of Space Applications Centre (SAC), Ahmedabad, the INSAT transmitter has also been indigenously developed through M/s. Avental, Hyderabad.  The functional tests of INSAT transmitter and antenna system have been completed. The bench tests, carried out on INSAT transmitter by SAC Ahmedabad, showed encouraging results.

 

Design and specification for the buoy hull, steel and aluminium components were completed and theirproduction from indigenous sources was ordered.  It is expected that the existing buoy network would be increased to 20 by the year 2003 through the indigenous production of data buoys.

 

                                                         

INSAT based transmission system for data buoy

Current meter mooring for NPOL

NDBP team has successfully designed and demonstrated a deep-sea current mooring with surface buoy for NPOL and trained the NPOL scientist and ship crew of INS Sagar Dhwani in the deployment and retrieval of current mooring system.

 

                                                                   

          Design and demonstration of Current Meters

                   mooring for 2000m depth  for NPOL by NDBP Group

6.1.3  Drifting Buoys

 

Drifting buoys have the capability for continuous measurement of SST and atmospheric pressure for a period of about a year. The data generated by the buoys are required for estimation of surface currents, which are useful for climate research, synoptic updates for weather prediction and provide sea truth for calibration and validation of satellite sensors. The data sets are transmitted, in near-real time, through Global Telecommunication System (GTS) to varioususers. The Project Team at NIO sends the processed data sets to INCOIS, NRSA, NCMRWF, IMD and SAC for utilization in the models and validation of Satellite sensors.

 

6.1.4  XBT Surveys

 

The XBT surveys are designed to collect vertical temperature profile data of the upper ocean up to a depth of 760 m, which would be used in studying the weather patterns, cyclones and variations in the mixed layer depth, etc. The objectives of the programme are (i) to understand and document the evolution of upper ocean thermal structure along selected XBT sections on annual time scales and to examine its inter-annual variability, (ii) to establish the relation between upper ocean summer heating and ensuing monsoon activity, (iii) to establish the relation between the heat content in the upper layers after the monsoon cooling and post-monsoon storms in the Bay of Bengal, and (iv) to provide sea truth information on subsurface temperature profiles for validation and calibration of data derived from satellite sensors. XBT observations were carried out along (i) Chennai-Port Blair-Calcutta, (ii) Chennai-Singapore, and (iii) Mumbai-Mauritius shipping routes onboard ships of opportunity (Merchant ships).

 

6.1.5  Current Meter Array

 

This project envisages deployment of a set of 3 Current Meter Arrays at pre-selected locations 93°E, 83°E and 76°E longitudes along the equator in the Indian Ocean for long-term monitoring of current structure. Each current meter array consists of 6 current meters (with pressure, temperature and conductivity sensors) placed at depths varying from near surface to near-bottom (50 m, 100 m, 200 m, 500 m, 1000 m, and near-bottom depth). The major objectives of the programme are (i) to understand the seasonal evolution of near-surface and sub-surface currents in the equatorial Indian Ocean, (ii) to understand the propagation of Kelvin waves and Rossby waves along the equator in relation to the evolution of surface mixed layer and upper layer heat content variability, and (iii) to address the deep-sea current variability in the equatorial Indian ocean in relation to climate change and exchange of deep water masses across the equator.

 

6.1.6  Sea Truth Campaigns

 

Satellite sensors like Radiometer, Altimeter, Scatterometer and Ocean Colour Monitor are being used to retrieve oceanic parameters viz SST, sea surface winds, ocean eddies, ocean colour, chlorophyll concentration, ocean waves, mixed layer depth etc. Sea truth is essential for validation of the satellite sensors and algorithms used for retrieval of these parameters.

 

During the year, 7 drifting buoys, 220 XBTs, 3 current meter arrays were deployed and 2 sea truth campaigns for validation of IRS-P4 sensors would be carried out by NIO.  A monthly climatology of surface currents was prepared using the drifter data collected from the Indian Ocean since 1985. XBT data were used in conjunction with TOPEX altimeter data for identifying oceanic eddies and estimated geotropic volume transport of the upper layers of the Indian Ocean.  Analysis of the data retrieved from Equatorial Current meter array is being carried out to study the deep-sea current variability in relation to climate change and exchange of deepwater masses across the equator.

 

6.2  Ocean Information Services  (OIS)

 

Ocean Information Services is designed for generation and dissemination of a wide range of data products and to provide services, such as coastal and ocean data and value added data products to the users.  In order to effectively generate ocean data products and disseminate them on operational basis, department established a dedicated Ocean Information Services (OIS) at Hyderabad, during February 1999. The objectives of the OIS programme are (i) generation and dissemination of near real time data and data products such as Sea Surface Temperature (SST) and Potential Fishing Zone advisories, upwelling zones, maps, eddies, chlorophyll, suspended sediment load, etc., (ii) providing need based ocean information consultancy services to the corporate sector industries, State and Central governments. The activities and achievements thereon are given under INCOIS.

 

6.3  Ocean Dynamics & Modelling

6.3.1  Indian Ocean Dynamics and Modelling (INDOMOD)

 

The INDOMOD project envisages adaptation of a suite of ocean models for study of open and coastal ocean processes and coupled ocean-atmospheric processes. The primary applications of these models are prediction of monsoon variability, storm surges associated with cyclones, waves, biological productivity and coastal processes. There are 13 separate sub-projects under the INCOMOD project addressing a specific activity pertaining to development of ocean-atmospheric modelling. The participating Institutes are Centre for Mathematical Modelling and Computer Simulation (C-MMACS), National Institute of Oceanography (NIO), Indian Institute of Tropical Meteorology (IITM), Indian Institute of Science (IISc), Indian Institute of Technology at Delhi (IIT-D), and Cochin University of Science and Technology (CUSAT).

 

A model for the prediction of upwelling/downwelling and frontal regions over continental shelf of Indian Sea and 3D coastal circulation models for west coast and Andhra coasts were developed to study the impact of tropical cyclone on coastal upwelling process and its influence on SST. A numerical model was developed to understand the circulation, mixing, salinity intrusion and pollutant dispersal in estuaries and coastal waters. A basic depth-averaged model and a coupled tidal circulation model were developed for Hoogly estuary and the sensitivity experiments were conducted. Studies on intra-seasonal oscillations of SST in the Western Bay were conducted for understanding the monsoon convection. A high performance computer facility was commissioned at C-MMACS, Bangalore to give a boost to the research activities of the INDOMOD project. Assimilation of Topex/Poseidon altimeter data into MOM as a part of the ocean data assimilation using Nudging technique was carried out. Thermodynamic ocean model and its application to determine SST over North Indian Ocean using COLA model wind forces were initiated. Tidal model for Gulf of Kachchh, Bombay High and Mandovi-Zuari estuarine system was developed. A model for Sea-breeze circulation in Goa coast is being developed.

 

6.4  Satellite Coastal and Oceanographic Research (SATCORE)

 

The SATCORE project envisages development of various algorithms and models for retrieval of met-ocean parameters (e.g. sea surface temperature, winds, wave parameters, bathymetry, suspended matter, mixed layer depth, chlorophyll, aerosol, water vapour, clouds, currents and sea level) from the data generated from Indian and foreign satellite sensors including IRS P4. Besides, the SATCORE programme would also carry out diagnostic studies and generation of forecast models, customisation of algorithms and development of related software packages.

 

During the year,

·     Algorithms and software were developed for atmospheric correction of OCM data, biogeochemical parameters, OCM data processing, etc. Validation experiments were conducted and found that algorithms worked well both in Arabian Sea and coastal waters.

 

·   A light model for mixed layer primary productivity was developed for the Arabian Sea. IRS-P4 data were used to study sediment dispersal in a tidal cycle.

·   Ocean Colour and SST were integrated for PFZ chart generation and experimental forecast was carried out for Gujarat, Kerala and Karnataka.

·     The feasibility studies towards utilizing satellite-derived information for sediment transport model were in progress, while modelling work for the prediction of coastal erosion/accretion was initiated.

·     MSMR data products were made operational.

·     Algorithms were developed to estimate Latent heat fluxes using MSMR and NCEP analysis.

·     Development/customisation of models was carried out.

·     Development of parameter retrieval algorithms from Megha-Tropiques and other future satellite missions of ISRO including Oceansat-2 and Radar Imaging Satellite was initiated.