Eye on weather stations’ accuracy amid new records

New Delhi: The Union ministry of earth sciences directed the India Meteorological Department (IMD) to ensure that all automated weather stations (AWS) are calibrated and maintained to ensure accuracy of weather data, a missive sent after a string of weather records were broken across the country — mostly via readings on automatic monitoring stations

New Delhi:

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The Union ministry of earth sciences directed the India Meteorological Department (IMD) to ensure that all automated weather stations (AWS) are calibrated and maintained to ensure accuracy of weather data, a missive sent after a string of weather records were broken across the country — mostly via readings on automatic monitoring stations.

Senior officials of the ministry of earth sciences said that AWS are key for expansion of weather monitoring, especially in remote parts of the country, and the government wants to ensure the data being released from these are accurate.

“In case, any record-breaking data is reported from any such automated stations, we have asked IMD to verify its accuracy before releasing the data. This will ensure unnecessary panic is not created among the public and an accurate picture is presented,” said a senior official of the ministry.

M Mohapatra, director general (meteorology) at IMD, said that over the years, the Met department has significantly improved the accuracy of its data and forecasts. They are also taking steps to widen the reach of data collection in remote parts of the country.

“We are ensuring that these sensors are maintained properly and the data collected through these stations are accurate. Over the last five years, we have managed to set up stations even in the most remote parts,” said Mohapatra.

Many AWS and Agromet weather stations — the latter are stations meant for weather information for farmers — have recorded extreme readings in Delhi and NCR. For instance, on Tuesday, southwest Delhi’s Ujwa recorded –0.8°C, the lowest minimum temperature to be recorded in any station in the national capital in at least two decades. On Monday, the station had recorded a minimum temperature of –0.5°C.

Similarly, on May 15, 2022, when Delhi’s representational weather station, Safdarjung, where temperatures are recorded manually, logged a maximum temperature of 45.6°C, northwest Delhi’s Mungeshpur and southeast Delhi’s Najafgarh — both AWS, tipped past 49°C, a number never before clocked on any of the city’s weather gauges.

To be sure, the immediate vicinity of these three areas are different and these could influence regional temperatures, and IMD set the two AWS only a year ago, therefore past trends were unavailable.

Delhi has five manual weather stations — at Safdarjung, Palam, Lodhi Road, Ridge and Ayanagar — where readings are collected manually, with a Met official using several instruments to note recordings at various intervals through the day.

The remaining — Najafgarh, Mayur Vihar, Sports Complex, Mungeshpur, Jafarpur and Pitampura — are automatic stations, where data is automatically recorded and transmitted through servers by pre-calibrated weather instruments.

IMD officials said the automatic stations were installed across the city from 2010 since the weather department required better coverage during the Commonwealth Games (CWG). These stations require minimal space in comparison to a full-fledged observatory.

IMD has also recently set up agromet weather stations in rural pockets of the Capital to help make forecasts for agriculture. These stations have specialised equipment to measure meteorological data such as temperature, rain, air humidity and also have sensors to forecast leaf wetness etc.

Till 2020, IMD had a network of over 700 AWS across the country.

Mahesh Palawat, vice-president (meteorology and climate change) at Skymet Weather Services, a private weather forecasting company, said a lack of accuracy in IMD’s AWS could be due tothe lack of maintenance and calibration of machines. In an ideal situation, he said, AWS can be an asset as it improves data collection and gives a clearer picture of how microclimates behave within a state.

“In AWS, sensors are set up in the open so it becomes imperative that the equipment is properly maintained and calibrated. We (Skymet) have a network of over 6,000 automated weather stations across the country and it becomes a great asset to us because it increases data points and improves forecasting,” Palawat said.