Tropospheric OH Radical Measurement Techniques: Recent Developments

  • A. Hofzumahaus
  • H.-P. Dorn
  • U. Platt

Summary

Two techniques to measure tropospheric OH radicals in situ are currently being developed in our laboratory. First, the already established laser long-path absorption spectroscopy is modified by folding a ligth path of about 4 km length in a multireflection system of 20 m base length. The detection limit will be about 1–2*106 OH cm-3. Second, a laser-induced fluorescence instrument has been build, which uses the 308 nm excitation of the OH radicals at a reduced pressure and has an expected detection limit of 5*105 cm-3. In both developments special care is taken to avoid the self-generation of OH from ozone UV-photolysis by the probing laser beam.

Keywords

Laser Pulse Energy High Detection Sensitivity Probe Laser Beam Photodissociation Cross Section Small Detection Volume 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

  1. (1).
    Perner, D., Piatt, U., Trainer, M., Hübler, G., Drummond, J., Junkermann, W., Rudolph, J., Schubert, B., Volz, A., Ehhalt, D.H., Rumpel, K.J. and Helas, G. (1987). Measurements of tropospheric OH concentrations: a comparison of field data with model predictions. J. Atm. Chem. 5, 185 – 216.CrossRefGoogle Scholar
  2. (2).
    Hübler, G., Perner, D., Platt, U., Tönnissen, A. and Ehhalt, D.H. (1984). Groundlevel OH radical concentration: New measurements by optical absorption. J. Geophys. Res. 89D, 1309 – 1319.CrossRefGoogle Scholar
  3. (3).
    Dorn, H.P., Callies, J., Platt, U. and Ehhalt, D.H. (1988). Measurements of tropospheric OH concentrations by laser long-path absorption spectroscopy. Tellus 40B, 437 – 445.CrossRefGoogle Scholar
  4. (4).
    Hofzumahaus, A., Dorn, H.-P., Callies, J., Platt, U. and Ehhalt, D.H. (1990). Tropospheric OH concentration measurements by laser long-path absorption spectroscopy. To be published.Google Scholar
  5. (5).
    Platt, U., Rateike, M., Junkermann, W., Hofzumahaus, A. and Ehhalt, D.H. (1987) Detection of atmospheric OH radicals. Free Rad. Res. Comms. 3, 165 – 172.CrossRefGoogle Scholar
  6. (6).
    Platt, U., Rateike, M., Junkermann, W., Rudolph, J. and Ehhalt, D.H.. (1987) New tropospheric OH measurements. J. Geophys. Res. 93D, 5159 – 5166.Google Scholar
  7. (7).
    Wang, C.C., Davis, L.I., Wu, C.H. and Japar, S. (1976). Laser-induced dissociation of ozone and resonance fluorescence of OH in ambient air. Appi. Phys. Lett. 28, 14 – 16.CrossRefGoogle Scholar
  8. (8).
    Hanabusa, M. and Wang, C.C. (1977). Pulsewidth dependence of ozone interference in the laser fluorescence measurement of OH in the atmosphere. J. Chem. Phys. 66, 2118 - 2120.CrossRefGoogle Scholar
  9. (9).
    Ortgies, G., Gericke, K.-H. and Comes, F.J. (1980). Is UV laser induced fluorescence a method to monitor tropospheric OH ? Geophys. Res. Lett. 7, 905 – 908.CrossRefGoogle Scholar
  10. (10).
    Davis, D.D., Rodgers, M.O., Fischer, S.D. and Asai, K. (1981). An experimental assessment of the 03/H20 interference problem in the detection of natural levels of OH via laser induced fluorescence. Geophys. Res. Lett. 8, 69 – 72.CrossRefGoogle Scholar
  11. (11).
    Shirinzadeh, B., Wang, C.C. and Deng, D.Q. (1987). Pressure dependence of ozone interference in the laser fluorescence measurements of OH in the atmosphere. Appi. Opt. 26, 2102 – 2105.CrossRefGoogle Scholar
  12. (12).
    Hard, T.M., Chan, C.Y. Mehrabzadeh, A.A. and O’Brien, R.J. (1989). Pressure dependence of ozone interference in the laser fluorescence measurement of OH in the atmosphere: comment. Appi. Opt. 28, 26 – 27.CrossRefGoogle Scholar
  13. (13).
    Hard, T.M., O’Brien, R.J., Chan, C.Y. and Mehrabzadeh, A.A. (1984). Tropospheric free radical determination by FAGE. Environ. Sci. Technol. 18, 768 – 777.CrossRefGoogle Scholar
  14. (14).
    Hard, T.M., Chan, C.Y., Mehrabzadeh, A.A., Pan, W.H. and O’Brien, R.J. (1986). Nature 322, 617 – 620.Google Scholar
  15. (15).
    Bakalyar, D.M., Davis, L.I., Chuan Guo, James, J.V., Spiros Kakos, Morris, P.T. and Wang, C.C. (1984). Shot noise limited detection of OH using the technique of laser-induced fluorescence. Appi. Opt. 23, 4076 – 4082.CrossRefGoogle Scholar
  16. (16).
    Davis, L.I., Chuan Guo, James, J.V., Morris, T.M., Postiff, R. and Wang, C.C. (1985). An airborne Lidar instrument for detection of OH using the technique of laser-induced fluorescence. J. Geophys. Res. 90, 12835 – 12842.CrossRefGoogle Scholar
  17. (17).
    Rodgers, M.O., Bradshaw, J.D., Sandholm, S.T., KeSheng, S. and Davis,D.D. (1985). A 2-Ä laser-induced fluorescence field instrument for ground-based and airborne measurements of atmospheric OH. J. Geophys. Res. 90, 12819 – 12834.CrossRefGoogle Scholar
  18. (18).
    Shirinzadeh, B., Wang, C.C. and Deng, D.Q. (1987). Diurnal variation of the OH concentration in ambient air. Geophys. Res. Lett. 14, 123 – 126.CrossRefGoogle Scholar

Copyright information

© ECSC, EEC, EAEC, Brussels and Luxembourg 1990

Authors and Affiliations

  • A. Hofzumahaus
    • 1
  • H.-P. Dorn
    • 1
  • U. Platt
    • 1
  1. 1.Kernforschungsanlage Jülich GmbHInstitut für Chemie 3: Atmospärische ChemieJülichGermany

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