IMD Classification of Monsoons

IMD Classification of Monsoons

Subject – Geography

Context – IMD forecast foiled by 24% rain shortfall.

Concept –

IMD maintains five rainfall distribution categories on an all-India scale. These are:

• Normal or Near Normal: When per cent departure of actual rainfall is +/-10% of LPA, that is, between 96-104% of LPA.
• Below Normal: When departure of actual rainfall is less than 10% of LPA, that is 90-96% of LPA.
• Above Normal: When actual rainfall is 104-110% of LPA.
• Deficient: When departure of actual rainfall is less than 90% of LPA.
• Excess: When departure of actual rainfall is more than 110% of LPA.

Long Period Average (LPA):

• It is the average rainfall recorded during the months from June to September, calculated during the 50-year period.
• It is kept as a benchmark while forecasting the quantitative rainfall for the monsoon season every year.

India Meteorological Department

• Formed in 1875, the India Meteorological Department (IMD) is the national meteorological service of the country and it is the chief government agency dealing in everything related to meteorology, seismology, and associated subjects.
• The administrative responsibilities of the Department are under the supervision of the Ministry of Earth Sciences of the Indian Government.
• The IMD is headquartered in New Delhi.