India is providing weather services to shipping communities since 1864, much before formal establishment of India Meteorological Department in 1875. There is a large data gap over the oceanic areas and ship data are one of the major source and provide important support to our forecasting systems both conventional and numerically based dynamic systems. Such data are being collected and archived in IMD and climatology of sea state are derived. Major utilization of ship data are as follows:
1. To issue Weather and sea bulletins both for shipping on the high seas and those plying in coastal waters (twice daily in undisturbed weather and 6 bulletins per day during storm periods).
2. To issue Bulletins for Indian Navy also called Fleet forecasts (twice daily), GMDSS bulletins, Port Warnings (daily once and more often as and when necessary), Fisheries warnings (4 times daily).
3. To issue warnings and bulletins to the various interests in the maritime states of India, coastal shipping and ships in the high seas for their specified areas of responsibility. These bulletins, include the 4 stage warnings viz. pre-cyclone watch, cyclone alert, cyclone warning and post land-fall outlook during cyclone situations.
4. To issue routine weather forecasts for shipping, fishermen, off-shore oil exploration etc. and issue of special weather warnings for severe weather phenomena like tropical cyclones over the Indian seas.
5. To watch over the weather developments in the Indian Seas and advise ships, ports, fishing vessels, the government agencies and other concerned officials, general public etc., in time, regarding adverse weather associated with cyclonic storms and depressions.
6. For archiving of surface marine data and preparation of Marine climatological summaries on yearly/decadal/30 year basis in the Indian Ocean, north of latitude 15S and between 20E to 100E, which are exchanged with International marine centres.