India Meteorological Department (IMD)
Context:
The India Meteorological Department (IMD) today announced that it expects monsoon rainfall to be normal this year. “Southwest monsoon seasonal (June to September) rainfall over the country as a whole is likely to be normal (96-104%),” the IMD said in its first stage Long Range Forecast (LRF) for monsoons.
About India Meteorological Department:
- The India Meteorological Department (IMD) is an agency of the Ministry of Earth Sciences of the Government of India.
- It is the principal agency responsible for meteorological observations, weather forecasting and seismology.
- IMD is headquartered – Delhi
- IMD is also one of the six Regional Specialised Meteorological Centres of the World Meteorological Organisation.
- It has the responsibility for forecasting, naming and distribution of warnings for tropical cyclones in the Northern Indian Ocean region, including the Malacca Straits, the Bay of Bengal, the Arabian Sea and the Persian Gulf.
History
The first meteorological observatories were established in India by the British East India Company. These included the Calcutta Observatory in 1785, the Madras Observatory in 1796 and the Colaba Observatory in 1826. Several other observatories were established in India during the first half of the 19th century by various provincial governments.
The Asiatic Society, founded in Calcutta in 1784 and in Bombay in 1804, promoted the study of meteorology in India. Henry Piddington published almost 40 papers dealing with tropical storms from Calcutta between 1835 and 1855 in The Journal of the Asiatic Society. He also coined the term cyclone, meaning the coil of a snake. In 1842, he published his landmark thesis, Laws of the Storms.
After a tropical cyclone hit Calcutta in 1864, and the subsequent famines in 1866 and 1871 due to the failure of the monsoons, it was decided to organise the collection and analysis of meteorological observations under one roof. As a result, the India Meteorology Department was established in 1875. Henry Francis Blanford was appointed the first Meteorological Reporter of the IMD. In May 1889, Sir John Eliot was appointed the first Director General of Observatories in the erstwhile capital, Calcutta. The IMD headquarters were later shifted to Shimla in 1905, then to Pune in 1928 and finally to New Delhi in 1944.
IMD became a member of the World Meteorological Organisation after independence on 27 April 1949. The agency has gained in prominence due to the significance of the monsoon rains on Indian agriculture. It plays a vital role in preparing the annual monsoon forecast, as well as in tracking the progress of the monsoon across India every season.
Tasks
IMD undertakes observations, communications, forecasting and weather services. In collaboration with the Indian Space Research Organisation, the IMD also uses the IRS series and the Indian National Satellite System (INSAT) for weather monitoring of the Indian subcontinent. IMD was first weather bureau of a developing country to develop and maintain its own satellite system.
IMD is one of the six worldwide Regional Specialised Meteorological Centres of the Tropical Cyclone Programme of the World Weather Watch of the World Meteorological Organization. It is regional nodal agency for forecasting, naming and disseminating warnings about tropical cyclone in the Indian Ocean north of the Equator.
New initiatives
The IMD launched System of Aerosol Monitoring and Research (SAMAR) in January 2016 to study the concentration of Black carbon, radiative properties of aerosols, environmental visibility and their climatological impacts. It would contain a network of 16 aethalometers, 12 sky radiometers and 12 nephelometers.
Satellites use by IMD for weather forecasting:
The meteorological data from the satellites is processed and disseminated by INSAT Meteorological Data Processing System (IMDPS) operational at IMD, New Delhi. At present, KALPANA-1 and INSAT-3A satellites are supporting the meteorological imaging and data collections.
It carries a Very High Resolution Radiometer (VHRR) capable of imaging the Earth in the visible, thermal infrared and water vapor bands. It is the main operational satellite and 48 scans of this satellite with a frequency of half an hour, are taken daily. The products derived from the satellite data include cloud images in the visible, infra-red and water vapour channels, atmospheric motion vectors, sea surface temperature, outgoing long-wave radiation, quantitative precipitation estimates and upper tropospheric humidity.
It carries VHRR, Charged Couple Device (CCD) camera and Data Relay Transponder (DRT). 24 Scans of VHRR and 6 scans of CCD camera of INSAT-3A are taken daily. The products derived from CCD camera are Normalised Difference Vegetation Index (NDVI) and Aerosol Optical Depth (AOD).
