Syllabus :GS 1/Geography
In News
- The India Meteorological Department (IMD) predicted ‘above normal’ rainfall (105% of the long-period average) during the 2025 southwest monsoon season (June-September).
- The monsoon is crucial for agriculture, economy, and water resources, providing around 70% of India’s annual rainfall.
- Since 2007, the accuracy of monsoon forecasts has improved significantly, with the absolute error in rainfall reducing by 21% from 1989-2006 to 2007-2024.
| Do you know? – Meteorology in India dates back to ancient times, with early texts like the Upanishads, Brihatsamhita, Arthashastra, and Meghdoot showing advanced understanding of weather and rain. – Scientific meteorology began in the 17th century, with Edmund Halley explaining the monsoon. The British established 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 understand rainfall patterns after the devastating 1876-78 Great Famine.
- Henry Francis Blanford, in the late 1800s, studied the relationship 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, although his predictions were still limited in accuracy.
- Sir Gilbert Walker in 1904, introduced statistical models using 28 parameters, identifying the Southern Oscillation (SO) as a key influence on the Indian monsoon.
- He divided India into three subregions for forecasting.
Scenario After Independence
- IMD continued using Walker’s model until 1987, but it became less effective due to changes 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, but issues persisted with the accuracy of regional forecasts.
New Models and Strategies
- In 2003, IMD introduced two new models based on 8 and 10 parameters.
- The two-stage forecast strategy was also implemented, although it had mixed results.
- In 2007, IMD developed a Statistical Ensemble Forecasting System, reducing the number of parameters to improve accuracy and introduced ensemble forecasts to increase 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 further improved forecast accuracy by combining global climate models, including MMCFS.
Source :IE
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