Context
The India Meteorological Department (IMD) expected ‘above everyday’ rainfall (105% of the long-period average) during the 2025 southwest monsoon season (June-September).
Key Highlights
- The monsoon is critical for agriculture, financial system, and water sources, providing around 70% of India’s annual rainfall.
- Since 2007, the accuracy of monsoon forecasts has progressed appreciably, with absolutely the errors in rainfall reducing by 21% from 1989-2006 to 2007-2024.
- Meteorology in India dates again to historical times, with early texts like the Upanishads, Brihatsamhita, Arthashastra, and Meghdoot showing superior knowledge of weather and rain.
- Scientific meteorology commenced in the 17th century, with Edmund Halley explaining the monsoon. The British installed early observatories in the 18th and 19th centuries, and Captain Piddington coined the term “cyclone.”
History of Monsoon Forecasting
- The IMD began forecasting the monsoon in 1877, driven by the need to recognize rainfall patterns after the devastating 1876-78 Great Famine.
- Henry Francis Blanford, within the late 1800s, studied the connection between Himalayan snow cover and monsoon rainfall.
- He made the first long-range forecast in 1886.
- Sir John Eliot took Blanford’s work forward by incorporating local weather conditions and data from the Indian Ocean and Australia, even though his predictions had been nonetheless limited in accuracy.
- Sir Gilbert Walker in 1904, brought statistical models using 28 parameters, identifying the Southern Oscillation (SO) as a key effect on the Indian monsoon.
- He divided India into 3 subregions for forecasting.
Scenario After Independence
- IMD endured the use of Walker’s version till 1987, however it was much less effective because of modifications in climate patterns and loss of correlation with key parameters.
- In 1988, The IMD shifted to a new regression model (Gowariker Model) using 16 variables, however issues continued with the accuracy of local forecasts.
New Models and Strategies
- In 2003, IMD delivered two new models based on 8 and 10 parameters.
- The two-stage forecast method was also implemented, even though it had combined effects.
- In 2007, IMD evolved a Statistical Ensemble Forecasting System, reducing the range of parameters to enhance accuracy and bringing ensemble forecasts to growth robustness.
- In 2012, the Monsoon Mission Coupled Forecasting System (MMCFS) was launched to combine ocean, atmospheric, and land data for better forecasts.
- In 2021, the Multi-Model Ensemble system in addition progressed forecast accuracy by combining international climate models, along with MMCFS.
Source: The Indian Express
UPSC Mains Practice Question
Q. What do you understand by the phenomenon of temperature inversion in meteorology? How does it affect weather and the inhabitants of the place? (2013)
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