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WORLD METEOROLOGICAL ORGANIZATION |
UNITED NATIONS ENVIRONMENT PROGRAMME |
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1. INTRODUCTION
The Indian involvement in monitoring atmospheric ozone dates back to 1928 when Dr. Royds made total ozone measurements from Kodaikanal with Dobson photoelectric Ozone Spectrograph as part of the first worldwide ozone measurements organized by Prof. G.M.B Dobson. The first Dobson Spectrophotometer was acquired by India Meteorological Department (IMD) in 1940.
The Indian ozone observational & research proqramme are as follows:
1.1 Observational Progromme:
(a) Total Ozone - the integrated amount of the ozone over any vertical column using Dobson Spectrophotometer.
(b) Vertical distribution of ozone - measured by ozonesondes and umkehr method.
(c) Ozone near the surface - using Brewer technique.
1.2 Research Programme:
Important areas in ozone research currently pursued are :
i. Ozone production; distribution and destruction mechanisms
ii. Global ozone trends
iii. Effect of ozone on global climate
iv. Ozone and the ecosystem
v. Ozone instrumentation
vi. Impact of UV-B radiation on ecosystems.
vii. U V Climatology
2. INDIAN ACTIVITIES
2.1 Total Ozone:
Total Ozone Measurements are being carried out from 5 stations by Indian Meteorological Department (IMD). Present network of Dobson Spectrophotometer consists of the following :
| S.No. | Name of Station | Lat. | Long. | since when |
|---|---|---|---|---|
| 1 | Srinagar | 34 ° 05'N | 74 ° 50'E | Nov. 1955 |
| 2 | New Delhi | 28 ° 35'N | 77 ° 12'E | Jan. 1955 |
| 3 | Varanasi | 25 ° 18'N | 83 ° 01'E | Dec. 1963 |
| 4 | Pune | 18 ° 32'N | 73 ° 51'E | Mar. 1973 |
| 5 | Kodaikanal | 10 ° 14'N | 77 ° 28'E | July 1957 |
| 6 | New Delhi | STANDARD | April 1969 |
The Spectophotometer at New Delhi serves as a National Standard.
Routine measurements of toal ozone are made a number of times a day (upto a maximum of six) by trained personnel from all the above stations. Whenever conditions permit, umkehr observations are also made form these stations to compute the vertical distribution of ozone. Recently to Brewer Ozone Spectrophotometers were procurrred. One was installed at National Ozone Centre, IMD at New Delhi and other at Observatory, Kodiakanal. It has an advantage over Dobson Spectrophotometer. In addition to ozone measurements, it will also measure SO2, NO2 and "UV-B".
2.1.1 Standardization
The network instruments are standardized against the National Standard at regular intervals. The National Standard is in turn, inter- compared against world standard in International Intercomparisons. India participated in such comparisons held at Belsk (1974), Boulder (1977) and Melbourne (1984) and Japan (1996) .
New Delhi is the National Ozone Centre for India and the Regional Ozone Centre for the Regional Association-II (Asia) of the World Meteorological Organization (WMO).
2.1.2 Publication of Data
The total ozone data & Umkehr data (vertical profile of Ozone) are being regularly sent in WMO format to the World Ozone Data Centre (WODC) Canada, and are being regularly published by the centre.
2.2 Vertical Distribution of Ozone
The development of an Indian ozonesonde was taken up in 1963. The first successful sounding was carried out in September 1964. The sonde was subsequently intercompared in 1970 in West Germany and went into network use in 1971. Since then fortnightly soundings are attempted from the following stations:
| Sl. No. | Name of Station | Lat. | Long. | since when |
|---|---|---|---|---|
| 1 | New Delhi | 28 ° 35'N | 77 ° 12'E | 1971 |
| 2 | Pune | 18 ° 32'N | 73 ° 51'E | 1971 |
| 3 | Thiruvananthapuram | 8 ° 29'N | 7 6 ° 57'E | 1971 |
| 4 | Dakshin Gangotri | 70 ° 03'S | 12 °E | 1986-89 |
| 5 | Maitri | 70 ° 48'S | 11 ° 42'E | 1990 |
2.2.1 Standardization:
The Indian ozonesonde was intercompared in West Germany in 1970 and later in 1980, and in Saskatoon, Canada in May 1991.
2.2.2 Allied Programme:
Indian Middle Atmosphere Programme (IMAP), operating since 1982, has provided an umbrella for integrating all Indian efforts on ozone research. Rocket programmes were stepped up during this period with payloads from Physical Research Laboratory, Ahmedabad and the National Physical Laboratory at Delhi. These, along with balloon and ground based measurements, have well characterized the ozonosphere over India.
2.3 Surface:
During the 70s, the electrochemical surface ozone measurement system was successfully developed. The system is successfully operating from the following stations:
| S. No. | Name of Station | Lat. | Long. | since when |
|---|---|---|---|---|
| 1. | New Delhi | 28 ° 35'N | 77 ° 12'E | 1972 |
| 2. | Pune | 18 ° 32'N | 73 ° 51'E | 1971 |
| 3. | Kodaikanal | 10 ° 14'N | 77 ° 28'E | 1976 |
| 4. | Thiruvananthapuram | 8 ° 20'N | 7 6 ° 57'E | 1973 |
| 5. | Nagpur | 21 ° 04'N | 79 ° 02'E | 1978 |
| 6. | Srinagar | 34 ° 05'N | 74 ° 50'E | 1981 |
| 7. | Dakshin Gangotri | 70 ° 03'S | 12 °E | 1986-89 |
| 8. | Maitri | 70 ° 48'S | 11 ° 42'E | 1990 |
2.4 UV-B Measurement
Regular measurement of UV-B radiation by filter photometer were started in year 1979 at Physical Research Laboratory , New Delhi. At present under Indian Middle Atmospheric Programme (IMAP) a chain of 7 stations have been established for routine measurement of global UV-B radiation at 280, 290, 300 and 310 nm using narrow band interference filters. The name and coordinates of the stations are listed below:
| S. No. | Name | Lat. | Long. | since when |
|---|---|---|---|---|
| 1. | N.P.L. New Delhi | 28.37'N | 77.10'E | 1979 |
| 2. | Shillong, I.M.D | 25.34'N | 91.53'E | 1986 |
| 3. | Jodhpur, I.M.D | 26.18'N | 73.01'E | 1986 |
| 4. | Pune University | 18.32'N | 73.51'E | 1986 |
| 5. | Waltair Andhra Univ. | 17.43'N | 83.14'E | 1986 |
| 6. | Mysore University | 12.20'N | 76.40'E | 1986 |
| 7. | Trivandrum, CESS | 08.29'N | 76.57'E | 1986 |
2.5 UV-Biometer
The measurement of Mininim Erythemal dose in entire UV-B in the UV-B range started at Delhi in 1995 January and is continuing .
2.6 UV Spectroradiometer
The spectral measurements of UV-B in the UV-B range in 1/2 nm interval started in 1989 and is continuing. The UV network is likely to expand and coordinated with international programme.
2.7 Indian Ozone Programme Over Antarctica
Considering the importance of Ozone measurements over Antarctica, an International Ozone Campaign had been organized during 1987. India participated in the campaign and had set up observational facilities at Dakshin Gangotri (DG) (70 oS, 12oE), Antarctica during the summer and winter expeditions of 1987.
India participated in the Regional Ozone Soundings in Antarctica, ROSA 93- campaign, to get information on the variations of the stratospheric ozone in a limited area of the southern polar region.
The soundings from Maitri (Antarctica) (70 ° 46'S, 11 ° 45'E) were carried out with the Indian electrochemical ozone sonde, which had earlier taken part in three successful international intercomparisions.
The spectral measurement of UV-B started in 1987 and is continuing- Minimum Erythermal dose measurement also started in 1993. In addition to this laser hetrodyne system has been installed in 1993 to study the ozone height profile. The National physical laboratory has established a millimeter- ground based instrument at Maitri, Antarctica for continuous ozone observation during the year under all weather condition.
2.8 Measurement of minor constituents
The status of Indian observations of various greenhouse molecules are as follows:
| 1. | CO2 | Not measured in routine but flux from biomass burning by portable gas chromatograph (PCG). |
| 2. | CH4 | Seven stations have been established under Methyne Campaign Programme in 1991-92. NPL is coordinating the Programme. |
| 3. | O3 | Extensive : Groundbased, Balloons, Rockets |
| 4. | NOx | NO in mesosphere (Rockets) NO2 in Tropo/Strat (Balloon) NO2 in Tropo/Strat (Laser Heterodying system) |
3 Publication of Results
A large number of papers have been published in various journals.
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