Anna Mani Built Nearly 100 Kinds of Weather Instrument at Pune, Supervised the First Indian Ozonesonde of 1964 and Headed the Wind Resource Survey of the 1980s

Anna Mani joined the Instrument Division of the India Meteorological Department (IMD) at Pune in 1948, after three years of training in England, and spent nearly three decades making Indian weather measurement self-reliant. The memoir written for the Indian National Science Academy (INSA) after her death counts nearly one hundred instruments among her work there and says that in five years’ time imports of all surface instruments had stopped. IMD’s own record credits her with the first Indian balloon-borne ozone sensor, which made its first successful ascent from Pune in September 1964.

A physicist from Peermade who was sent to learn meteorology

Anna Modayil Mani was born on 23 August 1918 at Peermade, in the Western Ghats of what was then the princely state of Travancore, the seventh of eight children. The INSA memoir says her father was an engineer with the Travancore Public Works Department, in charge of roads and bridges, and that he taught her not to accept a statement until she had tested it herself. She took an honours degree in physics and chemistry at Presidency College in Madras. In 1940 she enrolled for research at the Indian Institute of Science in Bangalore, in the physics department headed by C. V. Raman.

In Raman’s laboratory she worked first on the fluorescence and absorption of light in rubies and then on diamonds. Abha Sur, a historian of science at MIT, writes in an Indian Academy of Sciences essay that Mani recorded spectra of more than thirty diamonds, that some needed fifteen to twenty hours of exposure on a photographic plate, and that she published five single-author papers between 1942 and 1945. The memoir says the team’s main contribution was the discovery of mirror-image symmetry between the fluorescence and absorption spectra.

She submitted her doctoral dissertation to Madras University in August 1945. Sur reports that the university did not award the degree because she held no master’s degree, and the dissertation stayed in the library of the Raman Research Institute. Asha Gopinathan, who wrote the 2025 biography, says on a companion website that the reason is unclear. Mani herself, Sur writes, said the missing degree made little difference to her life.

The Government of India then gave her a scholarship to study meteorological instruments, a field where, the memoir says, the country needed expertise. Sur adds that physics research was her first preference and that this was the scholarship available. She went to England on a troop ship and spent three years there, trained by the British Meteorological Office. She toured stations in England and Scotland and spent three months at the National Physical Laboratory at Teddington learning about measurement standards. She returned in 1948, by which time India was independent.

The Pune workshop that made everything under one roof

The Instrument Division she joined was headed by S. P. Venkiteshwaran, whom the memoir describes as determined to make India self-sufficient in meteorological instruments. He was setting up a workshop in which raw material went in at one end and a finished instrument came out ready for calibration. The reason, the memoir explains, was that India then had almost no small industries to supply components, so every part had to be made under one roof. The workshop had a foundry and milling, turning, jig boring, sheet metal, plating, painting, carpentry and packing shops, and almost all of its machinery was imported.

Mani’s first job was to build a recording rain gauge. A hygrograph, thermograph, barograph and anemograph followed, nearly one hundred instruments in all, according to the memoir, and she prepared the engineering specifications, drawings and technical manuals for each. For pressure, the basic measurement of every weather service, she toured the country and set up regional standard barometers, checking them against the primary standards kept at Pune and Kolkata.

After Venkiteshwaran retired, the memoir says, the work fell to her. She wrote instruction manuals for every instrument in the observing network and sat on the Bureau of Indian Standards committee on meteorological instruments, preparing drawings so that private firms could make them. When India adopted the metric system she had every network instrument, manual and drawing converted from the British units, and the Pune workshop was re-equipped to match. The memoir calls that one of the most difficult tasks of her career. The World Meteorological Organization (WMO), in a tribute on her centenary, described the programme as one that made India self-sufficient in designing and manufacturing its own weather instruments.

Radiation stations for the International Geophysical Year

The International Geophysical Year of 1957 to 1958 gave her a second job. According to the memoir, the physicist K. R. Ramanathan asked her to set up a dense network of solar radiation stations across India, and four were opened in 1957 using radiometers obtained from Europe. At the same time she began designing the radiation instruments at Pune: the pyrheliometer, which measures direct sunlight, the pyranometer, which measures sunlight from the whole sky, and the pyrgeometer, which measures infrared radiation from the ground and sky. The memoir says these instruments had been a western monopoly with their design details kept secret, so the Pune team started from first principles. Ommen Chacko assisted her, and the first instrument out of the laboratory was the pyrheliometer, followed by the pyranometer and then the pyrgeometer.

The memoir reports that the Indian network had 24 radiation stations by 1969 and that the data were of a quality the WMO noticed, after which Pune was recognised as a Regional Radiation Centre for Asia and became a training centre for member countries in Asia and Africa. IMD’s own innovation page separately dates its IMD-made thermoelectric pyranometer, one particular design, to 1972; the memoir gives no year for the first Pune pyranometer.

Internationally, the memoir says she was chosen in 1962 as chair of the WMO working group on radiation instruments and observations. Under her chairmanship, 58 countries took part in a comparison of sunshine recorders from 1964 to 1968, and she served as technical director of the 1964 and 1969 International Pyrheliometer Comparisons at Davos in Switzerland. At the 1969 comparison she and other experts noticed a drift in the international pyrheliometric scale of 1957. The working group recommended re-evaluating it, and the memoir records that a new World Radiometric Reference replaced the old scale in 1980.

The ozone sonde of September 1964

Ozone work had a long Indian history before her. IMD says total ozone was first measured in India at Kodaikanal in 1928 and 1929, a hill station whose solar observatory has its own story in a century of Sun records. IMD acquired its first Dobson spectrophotometer, an instrument that measures the ozone in a whole column of air, in 1940. IMD names Ramanathan and Mani together as the people whose pioneer investigations established the main features of ozone over the tropics.

Ramanathan asked her to recalibrate all the Dobson instruments in India so that their data matched global records, and to develop an Indian sonde, a balloon-borne instrument that measures how ozone is distributed with height. The memoir says she took up the work in 1962, using the electrochemical sonde that A. W. Brewer of Oxford had developed in 1957 as her model; the UNEP Ozone Secretariat’s India report dates the start to 1963. The sonde pumps air through potassium iodide solution, ozone liberates iodine, and the resulting tiny current modulates a radio transmitter. IMD describes its version as a modified Brewer sonde.

After a series of early failures, the memoir says, she produced the first successful ozone sounding from Pune in September 1964. IMD and the UNEP report give the same month and year. E. L. Simmons, a physics lecturer at Wilson College in Mumbai who had studied under Brewer, helped at the start, and the memoir credits C. R. Sreedharan and G. Venugopal with the sonde’s later form. Within about five years the sonde had been improved enough for regular soundings from Thiruvananthapuram, Pune and New Delhi, and in 1970 it took part in an international sonde comparison in Germany.

IMD says ozone soundings became a routine part of the Indian Antarctic programme from the second expedition in 1982 to 1983, using the IMD-made sonde at the Dakshin Gangotri station, and that the soundings corroborated the 1985 discovery of the Antarctic ozone hole. Profile measurements at Dakshin Gangotri continued until the station was abandoned in 1989, and observations then began at the Maitri station. IMD adds that India is the only country making systematic ozone soundings from both the tropics and Antarctica. The treaty that followed the ozone hole is told in how the ozone layer is healing.

Solar handbooks and a wind survey after IMD

In 1969 Mani moved to Delhi as Deputy Director General of Observatories for Instruments, and she retired from IMD in 1976. She then joined the Raman Research Institute in Bangalore as a visiting professor for three years. The memoir says she worked with the group building a millimetre-wave telescope at Nandi Hills and measured the water vapour in the air there, finding a mean of 5 to 6 mm of precipitable water over Nandi Hills against 35 to 40 mm over Bangalore.

The Department of Science and Technology then asked her to organise measurements to assess India’s solar and wind resources. The result was two volumes on sunlight: the Handbook of Solar Radiation Data for India (1980) and Solar Radiation over India (1981). The memoir says the first gives observed data for 18 stations and the second computed data for 145 stations, calculated both by regression from sunshine or cloud records and by a theoretical model of how gases in the atmosphere scatter and absorb light. India’s installed solar capacity is now counted in gigawatts.

The wind survey followed. The memoir says the Ministry of Non-conventional Energy Sources began a wind resource programme in 1984 and asked Mani to run it from Bangalore. It started with 21 stations, mostly in Tamil Nadu and Gujarat, in 1984 to 1985, using 20-metre masts, and had data from about 150 stations when she left the project in 1996 because of poor health. She published the analysis in four volumes of Wind Energy Resource Survey in India. The National Institute of Wind Energy (NIWE) dates the national wind resource assessment programme to 1985, says it was assigned to the Field Research Unit of the Indian Institute of Tropical Meteorology at Bangalore with the National Aerospace Laboratories, and counts 448 stations from which that unit collected data before the programme moved to NIWE. The Press Information Bureau reported on 13 August 2026 that India’s installed wind capacity was 58.14 GW as of 31 July 2026, fourth in the world.

Honours and the record since

INSA elected Mani a Fellow in 1977 and gave her its K. R. Ramanathan Medal in 1987. She served on the council of the Indian Academy of Sciences from 1971 to 1979, edited its newsletter from 1980 to 1995 and was president of the Current Science Association from 1989 to 1994, according to the memoir. She was also a fellow of the Indian Meteorological Society, the American Meteorological Society, the American Geophysical Union and the Royal Meteorological Society. The memoir says WMO entrusted her with revising its Guide on instruments for its fourth edition, a job she finished in six months, and she worked briefly in Egypt as a radiation expert.

She died at Thiruvananthapuram on 16 August 2001. WMO marked her hundredth birthday on 23 August 2018, Google dedicated a Doodle to her 104th birthday on 23 August 2022, and the National Book Trust published Gopinathan’s biography, Anna Mani: The Uncut Diamond, in 2025 in its India@75 series. The memoir opens with a line she repeated often: “One test is worth ten thousand opinions.” WMO’s 2018 tribute quotes her reply when she was asked for advice by young people thinking of a career in meteorology: “First equip yourself for the job, make full use of your talents and then love and enjoy the work.”