• Buck, A., 1981: New equations for computing vapor pressure and enhancement factor. J. Appl. Meteor., 20 , 15271532.

  • Chauvenet, W., 1891: A Manual of Spherical and Practical Astronomy: Theory and Use of Astronomical Instruments. J. B. Lippincott and Co., 632 pp.

    • Search Google Scholar
    • Export Citation
  • Liou, K., 1980: An Introduction to Atmospheric Radiation. Academic Press, 392 pp.

  • Tanner, B., 1989: Final report for contract work. U.S. Army, Dugway Proving Ground, Dugway, UT.

  • Tanner, B., , Swiatek E. , , and Greene J. , 1993: Density fluctuations and use of krypton hygrometer in surface flux measurements. Conf. on Management of Irrigation and Drainage Systems, Park City, UT, ASCE,. 945952.

    • Search Google Scholar
    • Export Citation
  • van Dijk, A., 1999: Aliasing in one-point turbulence measurements: Theory, DNS and hotwire experiments. Ph.D. thesis, Delft University of Technology, Netherlands, 278 pp.

    • Search Google Scholar
    • Export Citation
  • Watanabe, K., , Zelikoff M. , , and Inn E. , 1953: Absorption coefficients of several atmospheric gases. AFCRC Tech. Rep.,. 5323. Geophysical Research Papers 21, 80 pp.

    • Search Google Scholar
    • Export Citation
  • Weast, R., , and Astle M. , 1980: Handbook of Chemistry and Physics. 61st ed. CRC Press.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 208 208 7
PDF Downloads 38 38 3

Oxygen Sensitivity of Krypton and Lyman-α Hygrometers

View More View Less
  • 1 Department of Meteorology and Air Quality, Wageningen University and Research, Wageningen, Netherlands
  • | 2 Royal Netherlands Meteorological Institute, De Bilt, Netherlands
  • | 3 Department of Meteorology and Air Quality, Wageningen University and Research, Wageningen, Netherlands
© Get Permissions Rent on DeepDyve
Restricted access

Abstract

The oxygen sensitivity of krypton and Lyman-α hygrometers is studied. Using a dewpoint generator and a controlled nitrogen/oxygen flow the extinction coefficients of five hygrometers associated with the third-order Taylor expansion of the Lambert–Beer law around reference conditions for oxygen and for water vapor were measured. Latent heat flux corrections for cross-talk of the sensible heat flux are given as a function of the Bowen ratio. The spread observed in oxygen sensitivities calls for individual oxygen calibrations for each apparatus. It is found that the separation between the tubes is the crucial parameter with respect to the oxygen sensitivity. The oxygen-related nonlinearities in the Lambert–Beer law are stronger than those associated with water vapor. This leads to a strong reduction of the oxygen sensitivity at a more or less constant water vapor sensitivity when the separation between the tubes is doubled from 1.3 to 2.6 cm. This characteristic is supported by a sensitivity analysis of the theoretical response relations of both types of hygrometers, based on multiple emission and absorption lines. The findings of Tanner et al. are confirmed—the results of a previous study strongly overestimate the oxygen sensitivity of today's krypton hygrometers.

Current affiliation: Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht, Netherlands

Corresponding author address: Dr. Arjan van Dijk, Institute for Marine and Atmospheric Research, Utrecht University, Utrecht, Netherlands. Email: a.vandijk@phys.uu.nl

Abstract

The oxygen sensitivity of krypton and Lyman-α hygrometers is studied. Using a dewpoint generator and a controlled nitrogen/oxygen flow the extinction coefficients of five hygrometers associated with the third-order Taylor expansion of the Lambert–Beer law around reference conditions for oxygen and for water vapor were measured. Latent heat flux corrections for cross-talk of the sensible heat flux are given as a function of the Bowen ratio. The spread observed in oxygen sensitivities calls for individual oxygen calibrations for each apparatus. It is found that the separation between the tubes is the crucial parameter with respect to the oxygen sensitivity. The oxygen-related nonlinearities in the Lambert–Beer law are stronger than those associated with water vapor. This leads to a strong reduction of the oxygen sensitivity at a more or less constant water vapor sensitivity when the separation between the tubes is doubled from 1.3 to 2.6 cm. This characteristic is supported by a sensitivity analysis of the theoretical response relations of both types of hygrometers, based on multiple emission and absorption lines. The findings of Tanner et al. are confirmed—the results of a previous study strongly overestimate the oxygen sensitivity of today's krypton hygrometers.

Current affiliation: Institute for Marine and Atmospheric Research Utrecht, Utrecht University, Utrecht, Netherlands

Corresponding author address: Dr. Arjan van Dijk, Institute for Marine and Atmospheric Research, Utrecht University, Utrecht, Netherlands. Email: a.vandijk@phys.uu.nl

Save