Modern meteorology depends upon near real time exchange of weather information across the entire globe. Telecommunication Division of India Meteorological Department provides the support function needed for meteorological data and processed products to the users, both national and international.
2.1 The Directorate of Telecommunication was set up in IMD at New Delhi in 1969 to cater the need of National Meteorological Service and strengthen the meteorological telecommunication in India. Since its inception, IMD maintains an extensive telecommunication network for speedy collection of meteorological information, both basic data and processed products, over the globe. The main telecommunication hub of the IMD’s telecommunication network is located at New Delhi. It is now termed as National Meteorological Telecommunication Centre (NMTC).
2.2 The Meteorological Telecommunication in IMD consists of an integrated network of point-to-point circuits and multipoint circuits which inter connect meteorological centers within the country and the world for receiving data and relaying it selectively. It is mainly organized on a two level basis, namely
The Meteorological Telecommunication Network within the Global Telecommunication System (GTS) of World Weather Watch (WWW) program of World Meteorological Organization (WMO), and The National Meteorological Telecommunication Network (NMTN)
2.3 GTS Network
As regards Meteorological Telecommunication Networks within the GTS, New Delhi telecommunication center is a designated Regional Telecommunication Hub (RTH) located on the Main Trunk Network (MTN). The MTN is the core network of GTS. It links together three World Meteorological Centers (WMCs) and 14 other RTHs on the MTN. The Centre is also a National Meteorological Centre (NMC) for telecommunication purposes within the framework of GTS.
2.4 The National Meteorological Telecommunication Network
The National Meteorological Telecommunication Network (NMTN) is designed to collect observational data and to receive and distribute meteorological information on a national level. Basic data from the observatories are collected at 19 collection centers (which are either Meteorological Centers at the State Capitals or Regional Meteorological Centre) by various telecommunication means. The stations included in the list of Global Observing System (GOS), the observational data of which are transmitted on GTS, are mostly connected by point-to-point links.
2.5 Satellite based data communication in IMD
Meteorological data and processed products containing 3 hourly INSAT images, surface and upper air data, aerodrome forecast, Wx. charts and model outputs, etc. exchanged over GTS are broadcast using World Space “Asia Star” Satellite. The broadcast covers large areas of Middle-East and South-East Asia at a downlink frequency of 1467- 1492 MHz.
A network of 26 VSATs have been installed at selected seismological observatories, Cyclone Detection Radar stations, Cyclone Warning Centers and Meteorological Centers for reception of observational data utilizing communication transponder of INSAT.
A receive only Satellite Data Dissemination System (SADIS) is in operation at New Delhi to receive aeronautical meteorological information from International Civil Aviation Organization (ICAO) Centers which are routed to four International Airports of India for National and International flight briefing and for providing data in GRIB/BUFR format for wind/temperature and Sig. Wx. charts.
India has been designated as an issuing service under the GMDSS programmed for Met. Area VIII (N) which covers the entire Indian Ocean and some parts of South- West Indian Ocean. Area of responsibility is between 10˚N and 80˚E.
India Meteorological Department is transmitting daily two GMDSS bulletins for Met. Area VIII (N), one at 0900 UTC and other at 1800 UTC. During Cyclone Season additional bulletins (4) are also being issued for GMDSS broadcast depending on the requirement. GMDSS bulletins are transferred to VSNL Earth Station at Pune using a dedicated telex terminal.
2.6 Other Communication facilities.
Various modes of communications such as VPN links, VSAT, VHF/ Walkie-Talkie, Mobile Phone and INTERNET facility are extensively being used for collection of observational data within the country. Services of Maritime Telex Stations (NAVTEX) are used for sending warnings/coastal weather bulletins by NBDP (Narrow Band Direct Printing telegraphy).
Telefax facilities have been provided at important meteorological offices for transmission/reception of Weather information. This facility has been extended to Cyclone Detection Radar stations, Cyclone Warning Centres and Meteorological Centres.
VHF/Walkie - Talkie facilities
Walkie-Talkie sets have been provided at 27 National/International Airports and other stations for real time exchange of Runway Visual Range (RVR) and meteorological information for safe aircraft flights. VHF facilities have been provided to 20 additional stations for exchange of meteorological information.
VSAT network facilities are available at 26 stations. These are some of the Seismological Observatories, Cyclone Detection Radar Stations, Cyclone Warning Centres, Meteorological Centres and at some other important observatories where no reliable communications system exist. This network operates utilizing communication transponders of INSAT.
High Speed Data Terminal (HSDT) facilities
HSDT are available at 26 stations. These terminals support communication using TCP/IP , email, SMS , Web ingest & dialup. These terminals are mostly located at Meteorological Centres located in State capitals. These terminals are used for collecting observational data from observatories and routing this data to AMSS located at Regional Met. Centres. Through these terminals Met Centres are receiving data from AMSS centre in their region.
3. Modernization of Meteorological Telecommunication
India Meteorological Department has modernized its National Meteorological Telecommunication Centre (NMTC) with a state-of-the-art switching computer system which has capabilities comparable with any advanced WMO Centers on the GTS. The existing RTH computer system is driven primarily by dual SUN server working on the stats-of-the-art distributed networking technology. The whole system has been designed to handle 128 channels. The system is capable of handling 2200 Mbytes of data/information every day. The system has many advanced facilities like handling VSAT links, Dial-up Telex, handling Met fax, Auto Fax in, Auto Fax out, Data Modem-in, Data Modem-out, exchange of T4 fax and handling sea area bulletins under Global Maritime Distress and Safety System. NMTC New Delhi is connected to Super computer of NCMRWF through a 2Mb/sec link, and the computer at Regional Specialized Meteorological Centre (RSMC) New Delhi through optical fiber link for instantaneous transmission of global observational data and processed information received via GTS.
Automatic Message Switching computers (AMSS) are also operational at the major International airports viz. Mumbai, Delhi, Calcutta, Chennai and Guwahati. The circuits linking New Delhi (Palam), Mumbai, Kolkata, Chennai and Guwahati Airport computers with the NMTC New Delhi are working at high and medium speed.
4. Public Services
4.1 Website of IMD
Website of IMD is operational since 1st June, 2000. It contains dynamically updated information on all India Weather and forecasts, special monsoon report, satellite cloud pictures (updated every three hours), animated satellite cloud pictures, Limited Area Model (LAM) generated products and prognostic charts, special weather warnings, tropical cyclone information and warnings, weekly and monthly rainfall distribution maps, earthquake reports, etc.. This also contains a lot of static information including temperature and rainfall normal over the country and a brief overview of the activities and services rendered by India Meteorological Department. This site can be accessed round the clock with the URL: http://www.imd.gov.in. The Regional Meteorological Centers have also their own websites.
4.2 Interactive Voice Response System (IVRS)
Popularly known as “Weather on telephone”, the Interactive Voice Response System (IVRS) is functioning with effect from July, 2000. One can access current weather and forecast for major Indian cities by dialing Toll free number 1800 180 1717.
5. Training in Meteorological Telecommunication
5.1 A Telecommunication Training Centre (TTC) was established in New Delhi in September, 1977 for imparting training in Meteorological Telecommunications. It is one of the international training centers in the field of meteorological telecommunication recognized by the World Meteorological Organization (WMO).
5.2 The Centre conducts the following courses:
5.3 The center is equipped with latest communication software and audio-visual aids. Ten numbers of computer work stations have been installed for imparting training in PC applications. A Weather Data Reception and Analysis System is also available for imparting training on processing and analyzing the meteorological information in the form of satellite imageries, raw data and charts.
5.4 The center has so far imparted training to 1064 departmental personnel. It has also imparted training to 88 foreign sponsored under various technical cooperation program such as ITEC, SCAAP of Government of India, Colombo Plan, UNDP and WMO.
6. Future Plan
The following up gradation of the existing facilities are under implementation :-
2. Installation of a new AMSS at RMC Nagpur and Guwahati.
3. To extend VPN network to Doppler radar stations.