Standardised Precipitation Index

About Standardised Precipitation Index: 

• It is used for estimating wet or dry condition based on precipitation variable. 
• The SPI calculation is based on the long-term precipitation record for a particular location and long-term period (longer than 30 years is desirable).
• This index is negative for drought and positive for wet conditions. As the dry or wet conditions become more severe, the index becomes more negative or positive respectively.
• Time scale: It includes timescales of 1, 2, 3, 6, 9, 12, 24, 36, 48, 60 and 72 months.

Key points about India Meteorological Department

• It was established in 1875. It is the National Meteorological Service of the country and the principal government agency in all matters relating to meteorology and allied subjects. 
• There are 6 Regional Meteorological Centres, each under a Deputy Director General with headquarters at Mumbai, Chennai, New Delhi, Calcutta, Nagpur and Guwahati.
• Mandate:
  • To take meteorological observations and to provide current and forecast meteorological information for optimum operation of weather-sensitive activities like agriculture, irrigation, shipping, aviation, offshore oil explorations, etc.
  • To warn against severe weather phenomena like tropical cyclones, norwesters, dust storms, heavy rains and snow, cold and heat waves, etc., which cause destruction of life and property.
  • To provide meteorological statistics required for agriculture, water resource management, industries, oil exploration and other nation-building activities.
  • To conduct and promote research in meteorology and allied disciplines.
• Nodal ministry: Ministry of Earth Sciences (MoES)
• Headquarter: New Delhi.

Q1: What is Precipitation?

It is any liquid or frozen water that forms in the atmosphere and falls back to the earth. It comes in many forms, like rain, sleet, and snow. Along with evaporation and condensation, precipitation is one of the three major parts of the global water cycle.

Source: Environmental hazards in the North-Eastern States

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