Abstract

We have investigated a technique that allows for the independent determination of the water vapor mixing ratio calibration factor for a Raman lidar system. This technique utilizes a procedure whereby a light source of known spectral characteristics is scanned across the aperture of the lidar system’s telescope and the overall optical efficiency of the system is determined. Direct analysis of the temperature-dependent differential scattering cross sections for vibration and vibration-rotation transitions (convolved with narrowband filters) along with the measured efficiency of the system, leads to a theoretical determination of the water vapor mixing ratio calibration factor. A calibration factor was also obtained experimentally from lidar measurements and radiosonde data. A comparison of the theoretical and experimentally determined values agrees within 5%. We report on the sensitivity of the water vapor mixing ratio calibration factor to uncertainties in parameters that characterize the narrowband transmission filters, the temperature-dependent differential scattering cross section, and the variability of the system efficiency ratios as the lamp is scanned across the aperture of the telescope used in the Howard University Raman Lidar system.

© 2011 Optical Society of America

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References

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  1. V. Sherlock, A. Hauchecome, and J. Lenoble, “Methodology for the independent calibration of Raman backscatter water vapor lidar systems,” Appl. Opt. 38, 5816–5837 (1999).
    [CrossRef]
  2. T. Leblanc and I. S. McDermid, “Accuracy of Raman lidar water vapor calibration and its applicability to long-term measurements,” Appl. Opt. 47, 5592–5603 (2008).
    [CrossRef] [PubMed]
  3. D. N. Whiteman, D. D. Venable, and E. Landulfo, “Comments on: Accuracy of Raman lidar water vapor calibration and its applicability to long-term measurements,” Appl. Opt. 50, 2170–2176 (2011).
    [CrossRef] [PubMed]
  4. A. Sobral-Torres, E. Landulfo, D. Whiteman, and D. Venable, “Water vapor Raman lidar independent calibration,” in Reviewed and Revised Papers presented at the 24th International Laser Lidar Conference, (Organizing Committee of the 24 International Laser Lidar Conference, 2008), pp. 204–207.
  5. E. Landulfo, R. F. Da Costa, A. S. Torres, F. J. S. Lopes, D. N. Whiteman, and D. D. Venable, “Raman water vapor lidar calibration,” Proc. SPIE 7479, 74790J (2009).
    [CrossRef]
  6. D. D. Venable, E. Joseph, D. Whiteman, D. Belay, R. Connell, and S. Walford, “Development of the Howard University Raman lidar,” Second Symposium on Laser Atmospheric Applications held at the 85th Annual Meeting of the American Meteorological Society, San Diego, California, January 2005, http://ams.confex.com/ams/pdfpapers/85650.pdf.
  7. M. Adam, B. B. Demoz, D. N. Whiteman, D. D. Venable, E. Joseph, A. Gambacorta, J. Wei, M. W. Shephard, L. M. Miloshevich, R. L. Herman, C. D. Barnet, J. Fitzgibbon, and R. Connell, “Water vapor measurements by Howard University Raman lidar during the WAVES 2006 campaign,” J. Atmos. Ocean. Technol. 27, 42–60 (2010).
    [CrossRef]
  8. D. N. Whiteman, “Examination of the traditional Raman lidar technique. I. Evaluating the temperature-dependent lidar equations,” Appl. Opt. 42, 2571–2592 (2003).
    [CrossRef] [PubMed]
  9. G. Avila, J. M. Fernández, G. Tojeda, and S. Montero, “Raman spectra and cross sections of H2O, D2O, and HDO in the OH/OD stretching regions,” J. Mol. Spectrosc. 228, 38–65 (2004).
    [CrossRef]
  10. W. E. Schneider and D. Goebel, Standards for “Calibration of optical radiation measurement systems,” in Laser Focus, Electro-Opt. 9, 12–20 (1984).
  11. Optronics Laboratories, 4632 36th Street, Orlando, Florida, USA (personal communication, 2009).
  12. M. Adam, “Notes on temperature-dependent lidar equations,” J. Atmos. Ocean. Technol. 26, 1021–1039 (2009).
    [CrossRef]
  13. C. M. Penney and M. Lapp, “Raman-scattering cross sections for water vapor,” J. Opt. Soc. Am. 66, 422–425 (1976).
    [CrossRef]
  14. L. M. Miloshevich, H. Vomel, D. N. Whiteman, and T. Leblanc, “Accuracy assessment and correction of Vaisala RS92 radiosonde water vapor measurements,” J. Geophys. Res. 114, D11305 (2009).
    [CrossRef]

2011 (1)

2010 (1)

M. Adam, B. B. Demoz, D. N. Whiteman, D. D. Venable, E. Joseph, A. Gambacorta, J. Wei, M. W. Shephard, L. M. Miloshevich, R. L. Herman, C. D. Barnet, J. Fitzgibbon, and R. Connell, “Water vapor measurements by Howard University Raman lidar during the WAVES 2006 campaign,” J. Atmos. Ocean. Technol. 27, 42–60 (2010).
[CrossRef]

2009 (4)

Optronics Laboratories, 4632 36th Street, Orlando, Florida, USA (personal communication, 2009).

M. Adam, “Notes on temperature-dependent lidar equations,” J. Atmos. Ocean. Technol. 26, 1021–1039 (2009).
[CrossRef]

E. Landulfo, R. F. Da Costa, A. S. Torres, F. J. S. Lopes, D. N. Whiteman, and D. D. Venable, “Raman water vapor lidar calibration,” Proc. SPIE 7479, 74790J (2009).
[CrossRef]

L. M. Miloshevich, H. Vomel, D. N. Whiteman, and T. Leblanc, “Accuracy assessment and correction of Vaisala RS92 radiosonde water vapor measurements,” J. Geophys. Res. 114, D11305 (2009).
[CrossRef]

2008 (2)

A. Sobral-Torres, E. Landulfo, D. Whiteman, and D. Venable, “Water vapor Raman lidar independent calibration,” in Reviewed and Revised Papers presented at the 24th International Laser Lidar Conference, (Organizing Committee of the 24 International Laser Lidar Conference, 2008), pp. 204–207.

T. Leblanc and I. S. McDermid, “Accuracy of Raman lidar water vapor calibration and its applicability to long-term measurements,” Appl. Opt. 47, 5592–5603 (2008).
[CrossRef] [PubMed]

2004 (1)

G. Avila, J. M. Fernández, G. Tojeda, and S. Montero, “Raman spectra and cross sections of H2O, D2O, and HDO in the OH/OD stretching regions,” J. Mol. Spectrosc. 228, 38–65 (2004).
[CrossRef]

2003 (1)

1999 (1)

1984 (1)

W. E. Schneider and D. Goebel, Standards for “Calibration of optical radiation measurement systems,” in Laser Focus, Electro-Opt. 9, 12–20 (1984).

1976 (1)

Adam, M.

M. Adam, B. B. Demoz, D. N. Whiteman, D. D. Venable, E. Joseph, A. Gambacorta, J. Wei, M. W. Shephard, L. M. Miloshevich, R. L. Herman, C. D. Barnet, J. Fitzgibbon, and R. Connell, “Water vapor measurements by Howard University Raman lidar during the WAVES 2006 campaign,” J. Atmos. Ocean. Technol. 27, 42–60 (2010).
[CrossRef]

M. Adam, “Notes on temperature-dependent lidar equations,” J. Atmos. Ocean. Technol. 26, 1021–1039 (2009).
[CrossRef]

Avila, G.

G. Avila, J. M. Fernández, G. Tojeda, and S. Montero, “Raman spectra and cross sections of H2O, D2O, and HDO in the OH/OD stretching regions,” J. Mol. Spectrosc. 228, 38–65 (2004).
[CrossRef]

Barnet, C. D.

M. Adam, B. B. Demoz, D. N. Whiteman, D. D. Venable, E. Joseph, A. Gambacorta, J. Wei, M. W. Shephard, L. M. Miloshevich, R. L. Herman, C. D. Barnet, J. Fitzgibbon, and R. Connell, “Water vapor measurements by Howard University Raman lidar during the WAVES 2006 campaign,” J. Atmos. Ocean. Technol. 27, 42–60 (2010).
[CrossRef]

Belay, D.

D. D. Venable, E. Joseph, D. Whiteman, D. Belay, R. Connell, and S. Walford, “Development of the Howard University Raman lidar,” Second Symposium on Laser Atmospheric Applications held at the 85th Annual Meeting of the American Meteorological Society, San Diego, California, January 2005, http://ams.confex.com/ams/pdfpapers/85650.pdf.

Connell, R.

D. D. Venable, E. Joseph, D. Whiteman, D. Belay, R. Connell, and S. Walford, “Development of the Howard University Raman lidar,” Second Symposium on Laser Atmospheric Applications held at the 85th Annual Meeting of the American Meteorological Society, San Diego, California, January 2005, http://ams.confex.com/ams/pdfpapers/85650.pdf.

M. Adam, B. B. Demoz, D. N. Whiteman, D. D. Venable, E. Joseph, A. Gambacorta, J. Wei, M. W. Shephard, L. M. Miloshevich, R. L. Herman, C. D. Barnet, J. Fitzgibbon, and R. Connell, “Water vapor measurements by Howard University Raman lidar during the WAVES 2006 campaign,” J. Atmos. Ocean. Technol. 27, 42–60 (2010).
[CrossRef]

Da Costa, R. F.

E. Landulfo, R. F. Da Costa, A. S. Torres, F. J. S. Lopes, D. N. Whiteman, and D. D. Venable, “Raman water vapor lidar calibration,” Proc. SPIE 7479, 74790J (2009).
[CrossRef]

Demoz, B. B.

M. Adam, B. B. Demoz, D. N. Whiteman, D. D. Venable, E. Joseph, A. Gambacorta, J. Wei, M. W. Shephard, L. M. Miloshevich, R. L. Herman, C. D. Barnet, J. Fitzgibbon, and R. Connell, “Water vapor measurements by Howard University Raman lidar during the WAVES 2006 campaign,” J. Atmos. Ocean. Technol. 27, 42–60 (2010).
[CrossRef]

Fernández, J. M.

G. Avila, J. M. Fernández, G. Tojeda, and S. Montero, “Raman spectra and cross sections of H2O, D2O, and HDO in the OH/OD stretching regions,” J. Mol. Spectrosc. 228, 38–65 (2004).
[CrossRef]

Fitzgibbon, J.

M. Adam, B. B. Demoz, D. N. Whiteman, D. D. Venable, E. Joseph, A. Gambacorta, J. Wei, M. W. Shephard, L. M. Miloshevich, R. L. Herman, C. D. Barnet, J. Fitzgibbon, and R. Connell, “Water vapor measurements by Howard University Raman lidar during the WAVES 2006 campaign,” J. Atmos. Ocean. Technol. 27, 42–60 (2010).
[CrossRef]

Gambacorta, A.

M. Adam, B. B. Demoz, D. N. Whiteman, D. D. Venable, E. Joseph, A. Gambacorta, J. Wei, M. W. Shephard, L. M. Miloshevich, R. L. Herman, C. D. Barnet, J. Fitzgibbon, and R. Connell, “Water vapor measurements by Howard University Raman lidar during the WAVES 2006 campaign,” J. Atmos. Ocean. Technol. 27, 42–60 (2010).
[CrossRef]

Goebel, D.

W. E. Schneider and D. Goebel, Standards for “Calibration of optical radiation measurement systems,” in Laser Focus, Electro-Opt. 9, 12–20 (1984).

Hauchecome, A.

Herman, R. L.

M. Adam, B. B. Demoz, D. N. Whiteman, D. D. Venable, E. Joseph, A. Gambacorta, J. Wei, M. W. Shephard, L. M. Miloshevich, R. L. Herman, C. D. Barnet, J. Fitzgibbon, and R. Connell, “Water vapor measurements by Howard University Raman lidar during the WAVES 2006 campaign,” J. Atmos. Ocean. Technol. 27, 42–60 (2010).
[CrossRef]

Joseph, E.

D. D. Venable, E. Joseph, D. Whiteman, D. Belay, R. Connell, and S. Walford, “Development of the Howard University Raman lidar,” Second Symposium on Laser Atmospheric Applications held at the 85th Annual Meeting of the American Meteorological Society, San Diego, California, January 2005, http://ams.confex.com/ams/pdfpapers/85650.pdf.

M. Adam, B. B. Demoz, D. N. Whiteman, D. D. Venable, E. Joseph, A. Gambacorta, J. Wei, M. W. Shephard, L. M. Miloshevich, R. L. Herman, C. D. Barnet, J. Fitzgibbon, and R. Connell, “Water vapor measurements by Howard University Raman lidar during the WAVES 2006 campaign,” J. Atmos. Ocean. Technol. 27, 42–60 (2010).
[CrossRef]

Landulfo, E.

D. N. Whiteman, D. D. Venable, and E. Landulfo, “Comments on: Accuracy of Raman lidar water vapor calibration and its applicability to long-term measurements,” Appl. Opt. 50, 2170–2176 (2011).
[CrossRef] [PubMed]

E. Landulfo, R. F. Da Costa, A. S. Torres, F. J. S. Lopes, D. N. Whiteman, and D. D. Venable, “Raman water vapor lidar calibration,” Proc. SPIE 7479, 74790J (2009).
[CrossRef]

A. Sobral-Torres, E. Landulfo, D. Whiteman, and D. Venable, “Water vapor Raman lidar independent calibration,” in Reviewed and Revised Papers presented at the 24th International Laser Lidar Conference, (Organizing Committee of the 24 International Laser Lidar Conference, 2008), pp. 204–207.

Lapp, M.

Leblanc, T.

L. M. Miloshevich, H. Vomel, D. N. Whiteman, and T. Leblanc, “Accuracy assessment and correction of Vaisala RS92 radiosonde water vapor measurements,” J. Geophys. Res. 114, D11305 (2009).
[CrossRef]

T. Leblanc and I. S. McDermid, “Accuracy of Raman lidar water vapor calibration and its applicability to long-term measurements,” Appl. Opt. 47, 5592–5603 (2008).
[CrossRef] [PubMed]

Lenoble, J.

Lopes, F. J. S.

E. Landulfo, R. F. Da Costa, A. S. Torres, F. J. S. Lopes, D. N. Whiteman, and D. D. Venable, “Raman water vapor lidar calibration,” Proc. SPIE 7479, 74790J (2009).
[CrossRef]

McDermid, I. S.

Miloshevich, L. M.

M. Adam, B. B. Demoz, D. N. Whiteman, D. D. Venable, E. Joseph, A. Gambacorta, J. Wei, M. W. Shephard, L. M. Miloshevich, R. L. Herman, C. D. Barnet, J. Fitzgibbon, and R. Connell, “Water vapor measurements by Howard University Raman lidar during the WAVES 2006 campaign,” J. Atmos. Ocean. Technol. 27, 42–60 (2010).
[CrossRef]

L. M. Miloshevich, H. Vomel, D. N. Whiteman, and T. Leblanc, “Accuracy assessment and correction of Vaisala RS92 radiosonde water vapor measurements,” J. Geophys. Res. 114, D11305 (2009).
[CrossRef]

Montero, S.

G. Avila, J. M. Fernández, G. Tojeda, and S. Montero, “Raman spectra and cross sections of H2O, D2O, and HDO in the OH/OD stretching regions,” J. Mol. Spectrosc. 228, 38–65 (2004).
[CrossRef]

Penney, C. M.

Schneider, W. E.

W. E. Schneider and D. Goebel, Standards for “Calibration of optical radiation measurement systems,” in Laser Focus, Electro-Opt. 9, 12–20 (1984).

Shephard, M. W.

M. Adam, B. B. Demoz, D. N. Whiteman, D. D. Venable, E. Joseph, A. Gambacorta, J. Wei, M. W. Shephard, L. M. Miloshevich, R. L. Herman, C. D. Barnet, J. Fitzgibbon, and R. Connell, “Water vapor measurements by Howard University Raman lidar during the WAVES 2006 campaign,” J. Atmos. Ocean. Technol. 27, 42–60 (2010).
[CrossRef]

Sherlock, V.

Sobral-Torres, A.

A. Sobral-Torres, E. Landulfo, D. Whiteman, and D. Venable, “Water vapor Raman lidar independent calibration,” in Reviewed and Revised Papers presented at the 24th International Laser Lidar Conference, (Organizing Committee of the 24 International Laser Lidar Conference, 2008), pp. 204–207.

Tojeda, G.

G. Avila, J. M. Fernández, G. Tojeda, and S. Montero, “Raman spectra and cross sections of H2O, D2O, and HDO in the OH/OD stretching regions,” J. Mol. Spectrosc. 228, 38–65 (2004).
[CrossRef]

Torres, A. S.

E. Landulfo, R. F. Da Costa, A. S. Torres, F. J. S. Lopes, D. N. Whiteman, and D. D. Venable, “Raman water vapor lidar calibration,” Proc. SPIE 7479, 74790J (2009).
[CrossRef]

Venable, D.

A. Sobral-Torres, E. Landulfo, D. Whiteman, and D. Venable, “Water vapor Raman lidar independent calibration,” in Reviewed and Revised Papers presented at the 24th International Laser Lidar Conference, (Organizing Committee of the 24 International Laser Lidar Conference, 2008), pp. 204–207.

Venable, D. D.

D. D. Venable, E. Joseph, D. Whiteman, D. Belay, R. Connell, and S. Walford, “Development of the Howard University Raman lidar,” Second Symposium on Laser Atmospheric Applications held at the 85th Annual Meeting of the American Meteorological Society, San Diego, California, January 2005, http://ams.confex.com/ams/pdfpapers/85650.pdf.

D. N. Whiteman, D. D. Venable, and E. Landulfo, “Comments on: Accuracy of Raman lidar water vapor calibration and its applicability to long-term measurements,” Appl. Opt. 50, 2170–2176 (2011).
[CrossRef] [PubMed]

M. Adam, B. B. Demoz, D. N. Whiteman, D. D. Venable, E. Joseph, A. Gambacorta, J. Wei, M. W. Shephard, L. M. Miloshevich, R. L. Herman, C. D. Barnet, J. Fitzgibbon, and R. Connell, “Water vapor measurements by Howard University Raman lidar during the WAVES 2006 campaign,” J. Atmos. Ocean. Technol. 27, 42–60 (2010).
[CrossRef]

E. Landulfo, R. F. Da Costa, A. S. Torres, F. J. S. Lopes, D. N. Whiteman, and D. D. Venable, “Raman water vapor lidar calibration,” Proc. SPIE 7479, 74790J (2009).
[CrossRef]

Vomel, H.

L. M. Miloshevich, H. Vomel, D. N. Whiteman, and T. Leblanc, “Accuracy assessment and correction of Vaisala RS92 radiosonde water vapor measurements,” J. Geophys. Res. 114, D11305 (2009).
[CrossRef]

Walford, S.

D. D. Venable, E. Joseph, D. Whiteman, D. Belay, R. Connell, and S. Walford, “Development of the Howard University Raman lidar,” Second Symposium on Laser Atmospheric Applications held at the 85th Annual Meeting of the American Meteorological Society, San Diego, California, January 2005, http://ams.confex.com/ams/pdfpapers/85650.pdf.

Wei, J.

M. Adam, B. B. Demoz, D. N. Whiteman, D. D. Venable, E. Joseph, A. Gambacorta, J. Wei, M. W. Shephard, L. M. Miloshevich, R. L. Herman, C. D. Barnet, J. Fitzgibbon, and R. Connell, “Water vapor measurements by Howard University Raman lidar during the WAVES 2006 campaign,” J. Atmos. Ocean. Technol. 27, 42–60 (2010).
[CrossRef]

Whiteman, D.

D. D. Venable, E. Joseph, D. Whiteman, D. Belay, R. Connell, and S. Walford, “Development of the Howard University Raman lidar,” Second Symposium on Laser Atmospheric Applications held at the 85th Annual Meeting of the American Meteorological Society, San Diego, California, January 2005, http://ams.confex.com/ams/pdfpapers/85650.pdf.

A. Sobral-Torres, E. Landulfo, D. Whiteman, and D. Venable, “Water vapor Raman lidar independent calibration,” in Reviewed and Revised Papers presented at the 24th International Laser Lidar Conference, (Organizing Committee of the 24 International Laser Lidar Conference, 2008), pp. 204–207.

Whiteman, D. N.

D. N. Whiteman, D. D. Venable, and E. Landulfo, “Comments on: Accuracy of Raman lidar water vapor calibration and its applicability to long-term measurements,” Appl. Opt. 50, 2170–2176 (2011).
[CrossRef] [PubMed]

M. Adam, B. B. Demoz, D. N. Whiteman, D. D. Venable, E. Joseph, A. Gambacorta, J. Wei, M. W. Shephard, L. M. Miloshevich, R. L. Herman, C. D. Barnet, J. Fitzgibbon, and R. Connell, “Water vapor measurements by Howard University Raman lidar during the WAVES 2006 campaign,” J. Atmos. Ocean. Technol. 27, 42–60 (2010).
[CrossRef]

E. Landulfo, R. F. Da Costa, A. S. Torres, F. J. S. Lopes, D. N. Whiteman, and D. D. Venable, “Raman water vapor lidar calibration,” Proc. SPIE 7479, 74790J (2009).
[CrossRef]

L. M. Miloshevich, H. Vomel, D. N. Whiteman, and T. Leblanc, “Accuracy assessment and correction of Vaisala RS92 radiosonde water vapor measurements,” J. Geophys. Res. 114, D11305 (2009).
[CrossRef]

D. N. Whiteman, “Examination of the traditional Raman lidar technique. I. Evaluating the temperature-dependent lidar equations,” Appl. Opt. 42, 2571–2592 (2003).
[CrossRef] [PubMed]

Appl. Opt. (4)

Electro-Opt. (1)

W. E. Schneider and D. Goebel, Standards for “Calibration of optical radiation measurement systems,” in Laser Focus, Electro-Opt. 9, 12–20 (1984).

J. Atmos. Ocean. Technol. (2)

M. Adam, “Notes on temperature-dependent lidar equations,” J. Atmos. Ocean. Technol. 26, 1021–1039 (2009).
[CrossRef]

M. Adam, B. B. Demoz, D. N. Whiteman, D. D. Venable, E. Joseph, A. Gambacorta, J. Wei, M. W. Shephard, L. M. Miloshevich, R. L. Herman, C. D. Barnet, J. Fitzgibbon, and R. Connell, “Water vapor measurements by Howard University Raman lidar during the WAVES 2006 campaign,” J. Atmos. Ocean. Technol. 27, 42–60 (2010).
[CrossRef]

J. Geophys. Res. (1)

L. M. Miloshevich, H. Vomel, D. N. Whiteman, and T. Leblanc, “Accuracy assessment and correction of Vaisala RS92 radiosonde water vapor measurements,” J. Geophys. Res. 114, D11305 (2009).
[CrossRef]

J. Mol. Spectrosc. (1)

G. Avila, J. M. Fernández, G. Tojeda, and S. Montero, “Raman spectra and cross sections of H2O, D2O, and HDO in the OH/OD stretching regions,” J. Mol. Spectrosc. 228, 38–65 (2004).
[CrossRef]

J. Opt. Soc. Am. (1)

Proc. SPIE (1)

E. Landulfo, R. F. Da Costa, A. S. Torres, F. J. S. Lopes, D. N. Whiteman, and D. D. Venable, “Raman water vapor lidar calibration,” Proc. SPIE 7479, 74790J (2009).
[CrossRef]

Other (3)

D. D. Venable, E. Joseph, D. Whiteman, D. Belay, R. Connell, and S. Walford, “Development of the Howard University Raman lidar,” Second Symposium on Laser Atmospheric Applications held at the 85th Annual Meeting of the American Meteorological Society, San Diego, California, January 2005, http://ams.confex.com/ams/pdfpapers/85650.pdf.

A. Sobral-Torres, E. Landulfo, D. Whiteman, and D. Venable, “Water vapor Raman lidar independent calibration,” in Reviewed and Revised Papers presented at the 24th International Laser Lidar Conference, (Organizing Committee of the 24 International Laser Lidar Conference, 2008), pp. 204–207.

Optronics Laboratories, 4632 36th Street, Orlando, Florida, USA (personal communication, 2009).

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Figures (12)

Fig. 1
Fig. 1

Schematic layout of the mapping setup. L, lamp; T, telescope; F, optical fiber; BS, wavelength separation unit (beam splitters, narrowband interference filters, collimating lenses, etc.); D, detector electronic components that convert the optical signals to measured electrical signals; S H out , water vapor channel signal; and S N out , nitrogen channel signal. The lamp (with intensity I in ) is scanned in the x y plane across the telescope aperture. ξ is the overall optical efficiency of the system, and the factor q X represents the conversion of the detected optical signal into the measured electrical signal. S X out is a function of the overall optical efficiency, the electrical efficiency, and the lamp intensity.

Fig. 2
Fig. 2

Nonlinear least squares fit function obtained for the uncalibrated 200 W tungsten–halogen lamp near the excitation and Raman wavelengths for the HURL system. The fitting parameter, C 2 = 3143.64 ± 1.78 , corresponds to the blackbody temperature and is found to be in good agreement with a 1000 W NIST traceable same-color temperature-calibrated lamp. I in , lamp intensity; h, Planck’s constant; c, the speed of light; k, Boltzmann’s constant; and λ, wavelength.

Fig. 3
Fig. 3

Transmission curves for water vapor and nitrogen filters. Dotted lines, digitized curves provided by the after-baseline-offset corrections; solid curves, nonlinear least squares fit to Gaussian functions. C 1 , C 2 , and C 3 are the fitting parameters for the peak transmission (amplitude), center wavelength ( λ 0 ), and FWHM of the corresponding Gaussian function, respectively. The solid nearly horizontal lines give the lamp function (in arbitrary units) in the vicinity of the bandpass of the respective filters.

Fig. 4
Fig. 4

Spectra of vibrational-rotational transitions at T = 273.15 K , associated with Raman scattering for nitrogen and water vapor. The excitation wavelength is 354.7 nm . The Q-branch vibrational transition for the nitrogen case (represented by the black vertical line) has been scaled down for graphical purposes. Also shown are the respective filter functions. The values of F ( T ) are also shown in the lower graph.

Fig. 5
Fig. 5

Experimental setup for the mapping apparatus. The lamp is approximately 1 m above the primary mirror and about 1 m below the system exit/entrance windows. The translation stages are Newport Corporation Model M-IMS600 High Performance Long-Travel Linear Stages, with submillimeter resolution and accuracy. This picture shows the lamp in a typical scan configuration located above the telescope-secondary-periscope system and below the exit baffle.

Fig. 6
Fig. 6

(A) Plot of the mapped data for a linear scan over a portion of the telescope for the water vapor (H, red dots), nitrogen (N, blue dots), and aerosol backscatter (L, black dots) channels. The drop-offs in the data are due to reduced reflectivity from obscurations in the telescope. 2D representations of a full mapping scan (B) before and (C) after the data mask has been applied. The obscurations and mirror edges cause higher efficiency ratios for the affected cells (B). The data-mask removes these values from the analysis. The thick red line at the bottom left in (C) shows the approximate location of the linear scan shown in (A).

Fig. 7
Fig. 7

(A) Histogram of the ratio of the measured signals in the water vapor channel to the measured signal in the nitrogen channel for 120 repeated measurements at a single location over the telescope mirror. The mean for the case shown was 1.153 ± 0.002 . (B) Histogram of the relative errors in the extreme differences for 14 scans taken between September 2009 and April 2010. A total of 207 cells were evaluated for each of the 14 scans. The mean relative error in the extreme differences was 1.28%.

Fig. 8
Fig. 8

Plot of lidar data (solid curve), i.e., ratio of water vapor channel to nitrogen channel signals and data from a collocated Vaisala RS92 radiosonde (dashed curve ) for July 24, 2010 at 0656 UT. The lidar data shown have 5 min temporal resolution and 30 m spatial resolution. The calibration constant obtained using the radiosonde data was 195.2 ± 3.0 g / kg for the case shown. The lidar data were corrected for F ( T ) and for differential transmission as discussed by Adam et al. [7], and the calibration constant was obtained for data between 0.5 and 1.5 km . The average value for all cases in this study was 195.8 ± 8.7 g / kg .

Fig. 9
Fig. 9

Graph of the temperature-dependent form of the water vapor mixing ratio calibration factor ( C R ) versus temperature. The curve allows the calculation of the error in the temperature-independent form of the water vapor mixing ratio calibration factor ( C R ) when the F ( T ) correction is not applied to the lidar data.

Fig. 10
Fig. 10

Graphical representation of the change in C R as a function of baseline offset for a temperature of 273.15 K . The plot corresponds to an additive increase in the transmission at each wavelength within the bandpass of the filter. The additive term is the value of the baseline offset in percentage points.

Fig. 11
Fig. 11

C R as a function of the filter’s central wavelength, λ 0 , for the nitrogen filter and the water vapor filter at a temperature of 273.15 K .

Fig. 12
Fig. 12

C R as a function of the filter’s FWHM for the nitrogen and water vapor filters at a temperature of 273.15 K .

Tables (1)

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Table 1 Upper Limits on the Uncertainties in Individual HURL Filter Parameters Permissible to Constrain the Relative Uncertainty in C R to 3% or Less a

Equations (18)

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P ( λ , z ) = q X P L ( λ L ) O X ( z ) A z 2 c τ 2 N X ( z ) F X ( T ) d σ X ( π ) d Ω ξ ( λ ) × exp [ 0 z [ α ( λ L , z ) + α ( λ , z ) ] d z ] + q X B ( λ ) .
F X ( T ) Δ λ X d σ X ( λ , T , π ) d Ω ξ ( λ ) d λ d σ X ( π ) d Ω ξ ( λ X ) ,
ξ ( λ ) = ε ( λ ) κ ( λ ) ,
w ( z ) mass H mass dryair = N H ( z ) M H N dryair ( z ) M dryair 0.7808 M H M dryair ( N H ( z ) N N ( z ) ) ,
w ( z ) 0.486 q N κ ( λ N ) F N ( T ) d σ N ( π ) d Ω ε ( λ N ) q H κ ( λ H ) F H ( T ) d σ H ( π ) d Ω ε ( λ H ) P ( λ H , z ) P ( λ N , z ) O N ( z ) O H ( z ) Δ τ ( λ N , λ H , z ) ,
P ( λ X , z ) = P ( λ X , z ) q X B ( λ X )
Δ τ ( λ N , λ H , z ) exp [ 0 z [ α ( λ N , z ) α ( λ H , z ) ] d z ]
C R 0.486 q N κ ( λ N ) d σ N ( π ) d Ω ε ( λ N ) q H κ ( λ H ) d σ H ( π ) d Ω ε ( λ H ) .
C R ( T ) 0.486 q N κ ( λ N ) F N ( T ) d σ N ( π ) d Ω ε ( λ N ) q H κ ( λ H ) F H ( T ) d σ H ( π ) d Ω ε ( λ H ) 0.486 q N κ ( λ N ) q H κ ( λ H ) σ N | ε N σ H | ε H .
σ X | ε X Δ λ X d σ X ( λ , T , π ) d Ω ε ( λ ) d λ = F X ( T ) d σ X ( π ) d Ω ε ( λ X ) .
Δ λ X d σ X ( λ , T , π ) d Ω ε ( λ ) d λ i { d σ X ( λ i , T , π ) d Ω ε ( λ i ) } .
S X , i out = q X Δ λ filter X ξ X , i ( λ ) I in ( λ ) d λ = q X κ i ( λ X ) Δ λ filter X ε X , i ( λ ) I in ( λ ) d λ .
S H N out = 1 n i = 1 n S H N , i out = 1 n i = 1 n S H , i out / S N , i out ,
S X , i in = Δ λ filter X ε X , i ( λ ) I in ( λ ) d λ = S X , i out q X κ i ( λ X ) .
S H N in = Δ λ filter H ε H ( λ ) I in ( λ ) d λ Δ λ filter N ε N ( λ ) I in ( λ ) d λ = q N κ ( λ N ) q H κ ( λ H ) S H N out .
κ ( λ N ) κ ( λ H ) = q H S H N in q N S H N out .
C R 0.486 S H N in S H N out d σ N ( π ) d Ω ε ( λ N ) d σ H ( π ) d Ω ε ( λ H ) ,
C R ( T ) 0.486 S H N in S H N out [ σ N | ε N σ H | ε H ] .

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