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WORLD METEOROLOGICAL ORGANIZATION |
UNITED NATIONS ENVIRONMENT PROGRAMME |
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Ozone and UV-B monitoring and research activities in the Czech Republic (CR) are mostly performed by specialists of the Czech Hydrometeorological Institute (CHMI) which is a governmental institution. A lot of these activities have been realized under international WMO/GAW and CEC (COPERNICUS and COST) programs, as specified below. Research works on ozone are also carried out by scientists from the Department of Meteorology of the Charles University in Prague and from the Institute of Atmospheric Physics of the Czech Academy of Science. These studies are supported by the National Grant Agency of CR. There is a close cooperation between the research groups mentioned above and some studies are performed in joint projects.
2. Monitoring and Measurements
2.1. Total Ozone
Daily observations of total ozone have been performed with the Dobson spectrophotometer No.074 at the Solar and Ozone Observatory of CHMI in Hradec Kralove (SOOHK) since 1962. Since 1994 the Brewer spectrophotometer No.098 has also been used for routine measurements of total ozone at SOOHK. The results are stored in the ozone database of CHMI and daily averages are submitted to the World Ozone Data Center (WODC) of WMO in Toronto, to cooperating stations of GAWGO30S in Central Europe and to the WMO Provisional Northern Hemisphere Ozone Mapping Center, Thessaloniki, Greece.
2.2. Vertical Distribution of Ozone
The balloon-borne ozone sondes have been launched three times per a week in January - April at the Aerological Observatory (AOPH) of CHMI in Praha since 1979. The Brewer-Mast (GDR) sonde was used in the period 1979-1991. Since 1992 the ECC model has been launched. The vertical profiles are stored in the ozone database of CHMI and in WODC, as well.
2.3. UV-B Solar Radiation
Measurements of UV-B solar radiation have been performed with the Brewer spectrophotometer in daily schedules at SOOHK since 1994. The instrument is regularly calibrated with external standard lamps and the erythemal DUV irradiance is calculated from each measurement. In 1995 the Robertson- Berger UV-Biometers were installed at SOOHK and at the GAW observatory of CHMI in Kosetice. Both instruments are operated and the data are recorded continuously.
3.1. Ozone Data Reduction and Re-evaluation
The total ozone data base from SOOHK of the period 1962-1990 was re- evaluated in 1991 with respect to the history of calibrations of the Dobson 074. The unified software package DOBSON for reduction of total ozone measurements was developed at SOOHK and spread through WMO to GAW/GO30S Dobson stations. A re-evaluation of the ozone vertical profiles from AOPH is planned to be done in the near future.
3.2. Consistency of the Dobson and Brewer Total Ozone Data Sets
Routine and experimental Dobson and Brewer simultaneous total ozone measurements from SOOHK were compared in 1994-1995. The original and updated extraterrestrial constants and zenith polynomials of the instruments were used to re-process the original data and to assess a consistency of both data sets created in routine field operation of the spectrophotometers. The differences between daily averages of total ozone due to the different methods of calculations were also investigated.
3.3. Comparison of the Brewer and R-B UV-B Measurements
Parallel measurements of erythemal UV-B solar radiation performed with the Brewer spectrophotometer and the Robertson-Berger UV-Biometer are being compared at SOOHK to assess the difference between both instruments. It is planned to calibrate the R-B meters in CR both with the Brewer instrument at SOOHK and towards international standards, as well.
3.4. Statistical Analyses
Statistical and trend analyses of total ozone from SOOHK of the period 1962- 1990 were completed and are available. Investigation of QBO, solar cycle and circulation effects on total ozone and vertical profiles in the territory of CR was done and published.
3.5. Ozone and UVB Relations
Simultaneous measurements of total ozone and erythemal DUV solar radiation performed with the Brewer spectrophotometer were analysed at SOOHK and a statistical model for calculation of DUV on clear days was developed and verified. The effect of clouds and atmospheric turbidity will be studied in the future and the results will be used for improvement of DUV forecasting (CEC project COST-713).
4. Applications
4.1. International Comparisons
Based on long-term experiences in measurements of total ozone the specialists from SOOHK assisted in realization of the intercomparisons of Dobson spectrophotometers organized by WMO in Hradec Kralove (1993), Izana (1994), Boulder (1995) and Arosa (1995).
4.2. Ozone and UV-B Nowcasting
Since 1993 daily reports on actual condition of the ozone layer in CR have been produced at SOOHK and presented for the public. Since 1995 DUV levels and sunburn times have also been incorporated in these reports for the period April-August. It is expected that a regular forecasting of total ozone, DUV irradiances and UV-index will be implemented by CHMI in the next two years.
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