Hidden Stories | Pre-dawn balloon launches to scanning instruments: This observatory in Pune has been decoding skies since 1856

CAgMO is included in the list of the World Meteorological Organisation (WMO) centennial observatories across the globe. (Express Photo by Arul Horizon)

Everybody is interested in the weather, but it is in places like CAgMO that experts tabulate, calculate and comprehend the varying elements of the weather. Located on the campus of the Agriculture College in Shivajinagar since 1856, surrounded by open fields and with the Chaturshringhi hill in the background, CAgMO has been recording the temperature, humidity, rainfall, cloud condition, radiation, pollution level and dew in Pune.

It has been a part of intense conversations, such as with the offices of the Indian Air Force in Pune. On some mornings during conflicts, such as the Kargil war, or a natural calamity, like a cyclone, the phone calls come every hour. The officers want to know the wind speed and direction at 1,000 ft, 2,000 ft and above before pilots take off or land. “It is very important to have accurate data,” says Mohadikar, a veteran of more than 35 years, who is set to retire in 2026.

Watching the weather

CAgMO was set up by the British and is among the few meteorological observatories worldwide that is more than 200 years old. It is included in the list of the World Meteorological Organisation (WMO) centennial observatories across the globe. The offices of CAgMO overlook a ground studded with various types of instruments.

“An observatory must be located in the open, so as to get full exposure to the weather conditions,” says meteorologist Madhukar More. Here, one day is calculated from 8.30 am to, 24 hours later, 8.30 am the next day. The office is working 24/7, and several recordings, such as wind velocity and direction, atmospheric and soil temperature, pressure and humidity, are taken every three hours, as is the global practice. The readings at 8.30 am and 5.30 pm are of critical importance in making forecasts and understanding the day’s or night’s weather.

“At 8.20 am, in observatories across India, meteorologists would be recording the data that will be uploaded at 8.30 am. This allows weather forecasters to get a complete picture from across the country,” says More. There are three cup counter anemometers that are installed at different heights and More leads the way to the one erected at 3 metres.

Around CAgMO, the rows of palm trees are swaying in the breeze. “We use units like metre per second, knots and kmph. We report it in knots,” says More. The wind vane shows that the wind is blowing from the East to West. “Till March, it will be the Easterlies. After May, the wind direction changes and the Westerlies begin to blow. When the South West Monsoon is approaching, the wind direction is Westerlies,” says More.

Among the other instruments are wet and dry bulb thermometers, thermometers measuring soil temperature at various depths, a pool of water that is used to study evaporation, and a hair hygrometer. On the terrace of a building are a number of other instruments. A glass sphere helps measure the duration of bright sunshine. “As children, we used to play with concave lenses to burn paper. The Campbell–Stokes Bright Sunshine Hours Recorder works on the same principle. The rays of the sun leave burn marks on the special paper, so that we can gauge how cloudy or clear the sky is,” says More.

Technological advances

A tall pole on the grounds looks like yet another instrument, but it is more than the sum of its parts. This is the Automatic Weather Station that carries digital instruments to measure the various weather parameters. “It constantly transmits data as well. You can get weather updates on your mobile. While this digital device is still under study, it is a valuable intervention in remote, inaccessible places, such as the Himalayas,” says More, adding that digital devices will not impact manual weather recording. Every day, it is still human meteorologists who make the rounds of instruments and help bring weather news to Pune.