IMD 150: The changing skies of our weather office

As it turns 150, the Indian Meteorological Department can look back at a legacy of continuous evolution. In the future, it needs to grow its observation network and sharpen its city forecasts
Image used for representational purposes only.
Image used for representational purposes only.Express Illustration | Mandar Pardikar
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4 min read

The India Meteorological Department (IMD) celebrates 150 years of distinguished service today. From its humble beginnings in 1875, the IMD has evolved into one of the world’s most advanced and reliable meteorological organisations. Equipped with state-of-the-art technology and guided by a legacy of scientific excellence, the IMD has been at the forefront of safeguarding lives and livelihoods through weather forecasts and early warning systems. As the institution commemorates this historic milestone, it’s a moment to reflect on its remarkable journey and contributions to India and the global community.

The British colonial government had a natural fascination for meteorological observations. By 1874, there were about 80 observatories across India. On January 15, 1875, Henry Blanford assumed charge as the head of the newly formed IMD. The department was established against the backdrop of the havoc caused by a tropical cyclone in 1864 and two famines in 1866 and 1871 that killed tens of thousands.

At the time, the IMD’s two priority areas were shipping and agriculture, the lifelines of the economy. The focus sharpened and broadened in subsequent decades. In a country suffering from chronic droughts and erratic rainfall, the department established a division of agricultural meteorology as early as 1932. After the Second World War, civil aviation experienced rapid growth, requiring significant operational support as all phases of aircraft operations are influenced by weather. Today, the IMD caters to the diverse needs of multiple sectors including construction and energy.

In recent times, the department started growing rapidly from 2006 when it became part of the newly created ministry of earth sciences. The ministry provided IMD with funds to upgrade its observational network and develop state-of-the-art prediction systems. Today, the IMD’s network comprises more than 2,000 surface observatories, 6,000 rain gauges, more than 100 upper-air observatories, 40 remote-sensing Doppler radars, several agro-meteorological stations, and advanced satellite systems.

The Monsoon Mission—an initiative launched by the ministry in 2012 and followed by subsequent phases started in 2017 and 2021—has played a pivotal role in enhancing forecasting capabilities. By 2017, the resolution of global weather prediction models had increased tenfold over a decade or so, from 120 km to 12 km, while regional models improved from 27 km to 3 km. The lead period for these models also quickened from 48 hours to 10-day forecasts with three-hour intervals. The IMD now operates climate models for extended-range predictions, for 10-30 days, and seasonal forecasts extending up to nine months.

One of the most critical services is the tropical cyclone forecast, whose capabilities improved substantially after the devastating 1999 Odisha ‘super cyclone’, in which approximately 10,000 lives were lost in the state. In 2013, when a similarly intense cyclone—named Phailin—struck Odisha, the casualties were fewer than 10, showcasing the remarkable improvement in forecasting. The accuracy of cyclone forecasts has increased from about 20 percent in the early 2000s to over 80 percent by 2020.

There have also been significant improvements in predicting heavy rainfall events, particularly in day-3 forecasts, which are now more accurate at times than day-1 forecasts. In 2017, the ambitious Thunderstorm Project was launched to enhance the accuracy of thunderstorm and lightning forecasts. As a result, the precision for 24-hour predictions and three-hour ‘nowcast’ guidance has significantly improved. Heatwave forecasts today move seamlessly from short ranges to seasonal time scales, achieving higher success rates. In 2019, the IMD also launched an air-quality warning system for Delhi.

The department now employs two advanced ‘ensemble’ systems that analyse multiple forecasts and provide 10-day predictions with high reliability up to five days—an improvement of two days from earlier. Probabilistic forecasts, such as the Extreme Forecast Index (EFI), offer a lead time of 4-5 days for extreme weather events. These medium-range forecasts have proven invaluable for farmers.

Independent evaluations have demonstrated that IMD’s agro-meteorological advisories significantly benefit farmers, particularly those in low-income groups. It was inferred that the economic investment of Rs 1 in these advisories realises a 50-fold economic benefit through gains to below-poverty-line farming and fishing families.

Improved warnings with increased accuracy and longer lead times have helped disaster managers and the general public minimise loss of lives and property. This progress stems from systematic advancements in data assimilation and the development of high-resolution prediction models.

While significant progress has been made, there remain areas for improvement. The skill of deterministic forecasts for extremely heavy rainfall events is limited to 1-2 days. Accurately predicting such events with more lead time and associated flooding remains a considerable challenge.

Local weather forecasts, particularly for major cities, require further refinement. Seasonal forecasts, though improved, still fall short of their potential predictability, necessitating better simulation of monsoon teleconnections and addressing systematic model errors.

The improvement of observation networks will significantly enhance data quality and forecast efficiency. To deepen the understanding of monsoon dynamics and cloud physics, research testbeds at Bhopal and Mumbai were established.

Future advances in numerical weather prediction will focus on implementing global ensemble prediction systems with horizontal resolutions of 1-3 km, enabling a more accurate representation of physical processes. The IMD is transitioning to an ensemble prediction system with a 6-km horizontal resolution, an improvement over the current 12-km resolution. With computing resources enhanced by supercomputers capable of 20-petaflop speeds (equivalent of 20,000 terabytes), the IMD is well positioned to achieve these advancements.

By embracing cutting-edge technologies and continually improving its forecasting systems, the IMD can sustain its legacy as a global leader in weather and climate services. From its origins in 1875 to its position today as a beacon of scientific excellence, the department’s journey underscores its unwavering commitment to serving the nation.

(Views are personal)

Madhavan Nair Rajeevan

Vice Chancellor, Atria University, Bengaluru; Former Secretary, Ministry of Earth Sciences

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