Atmospheric Measurement Techniques Discussions
www.atmos-meas-tech-discuss.net
1867-8610
2
6
2009
10.5194/amtd-2-2919-2009
http://www.atmos-meas-tech-discuss.net/2/2919/2009/
http://www.atmos-meas-tech-discuss.net/2/2919/2009/amtd-2-2919-2009.html
http://www.atmos-meas-tech-discuss.net/2/2919/2009/amtd-2-2919-2009.pdf
2919
2982
2009-11-18
Extending differential optical absorption spectroscopy for limb measurements in the UV
J. Puķīte
janis.pukite@mpch-mainz.mpg.de
S. Kühl
T. Deutschmann
U. Platt
T. Wagner
Max Planck Institute for Chemistry, J. J. Becher Weg 27, 55128 Mainz, Germany
Institute of Environmental Physics, University of Heidelberg, Im Neuenheimer Feld 229, 69120 Heidelberg, Germany
Methods of UV/VIS absorption spectroscopy to determine the constituents in
the Earth's atmosphere from measurements of scattered light are often based
on the Beer-Lambert law, like e.g. Differential Optical Absorption
Spectroscopy (DOAS). Therefore they are strictly valid for weak absorptions
and narrow wavelength intervals (strictly only for monochromatic radiation).
For medium and strong absorption (e.g. along very long light-paths like in
limb geometry) the relation between the optical depth and the concentration
of an absorber is not linear anymore. As well, for large wavelength intervals
the wavelength dependent differences in the travelled light-paths become
important, especially in the UV, where the probability for scattering
increases strongly with decreasing wavelength.
<br><br>
However, by taking into account these dependencies, the applicability of the
DOAS method can be extended also to cases with medium to strong absorptions
and for broader wavelength intervals.
<br><br>
Common approaches for this correction are the so called air mass factor
modified (or extended) DOAS and the weighting function modified DOAS. These
approaches take into account the wavelength dependency of the slant column
densities (SCDs), but also require a-priori knowledge for the air mass factor
or the weighting function calculation by radiative transfer modelling.
<br><br>
We describe an approach that considers the fitting results obtained from
DOAS, the SCDs, as a function of wavelength and vertical optical depth and
expands this function into a Taylor series of both quantities. The Taylor
coefficients are then applied as additional fitting parameters in the DOAS
analysis. Thus the variability of the SCD in the fit window is determined by
the retrieval itself.
<br><br>
This new approach gives a description of the SCD that is as close to reality
as desired (depending on the order of the Taylor expansion), and is
independent from any assumptions or a-priori knowledge of the considered
absorbers.
<br><br>
In case studies for simulated and measured spectra in the UV (332–357 nm),
we demonstrate the improvement by this approach for the retrieval of vertical
profiles of BrO from the SCIAMACHY limb observations. Compared to the
standard DOAS approach, the results for BrO obtained from the simulated
spectra are closer to the true profile, when applying the new method for the
SCDs of ozone. Also for the measured spectra the agreement with validation
measurements is improved significantly, especially for cases with strong
ozone absorption.
<br><br>
While the focus of this article is on the improvement of the BrO profile
retrieval from the SCIAMACHY limb measurements, the novel approach may be
applied for a wide range of DOAS retrievals.
Bovensmann, H., Burrows, J. P., Buchwitz, M., Frerick, J., Noël, S., Rozanov, V. V., Chance, K. V., and Goede, A. P. H.: SCIAMACHY: Mission objectives and measurement modes, J. Atmos. Sci., 56, 127–150, 1999.
Brewer, A. W., McElroy, C. T., and Kerr, J. B.: Nitrogen dioxide concentrations in the atmosphere, Nature, 246, 129–133, 1973.
Buchwitz, M., Rozanov, V. V., and Burrows, J. P.: A near-infrared optimized DOAS method for the fast global retrieval of atmospheric CH<sub>4</sub>, CO, CO<sub>2</sub>, H<sub>2</sub>O, and N<sub>2</sub>O total column amounts from SCIAMACHY Envisat-1 nadir radiances, J. Geophys. Res., 105(D12), 15231-15245, 2000.
Burrows, J. P., Weber, M., Buchwitz, M., Rozanov, V., Ladstätter-Weißenmayer, A., Richter, A., Debeek, R., Hoogen, R., Bramstedt, K., Eichmann, K.-U., Eisinger, M., and Perner, D.: The Global Ozone Monitoring Experiment (GOME): Mission Concept and First Scientific Results, J. Atmos. Sci., 56, 151–171, 1999.
Butz, A., Bösch, H., Camy-Peyret, C., Chipperfield, M., Dorf, M., Dufour, G., Grunow, K., Jeseck, P., Kühl, S., Payan, S., Pepin, I., Pukite, J., Rozanov, A., von Savigny, C., Sioris, C., Wagner, T., Weidner, F., and Pfeilsticker, K.: Inter-comparison of stratospheric O<sub>3</sub> and NO<sub>2</sub> abundances retrieved from balloon borne direct sun observations and Envisat/SCIAMACHY limb measurements, Atmos. Chem. Phys., 6, 1293–1314, 2006.
Coldewey-Egbers, M., Weber, M., Buchwitz, M., and Burrows, J. P.: Application of a modified DOAS method for total ozone retrieval from GOME data at high polar latitudes, Adv. Space Res., 34, 749–753, doi:10.1016/j.asr.2003.05.051, 2004.
Coldewey-Egbers, M., Weber, M., Lamsal, L. N., de Beek, R., Buchwitz, M., and Burrows, J. P.: Total ozone retrieval from GOME~UV spectral data using the weighting function DOAS approach, Atmos. Chem. Phys., 5, 1015–1025, 2005.
Deutschmann, T.: Atmospheric radiative transfer modelling using Monte Carlo methods, Diploma Thesis, Universität Heidelberg, 2009.
Diebel, D., de Beek, R., Burrows, J. P., Kerridge, B., Munro, R., Platt, U., Marquard, L., and Muirhead, K.: Trace gas study: Detailed analysis of the retrieval algorithms selected for the level~1–2 processing of GOME data, Tech Rep., Eur. Space Agency (ESA), Section~5, 5–150~pp., 1995.
Dorf, M., Bösch, H., Butz, A., Camy-Peyret, C., Chipperfield, M. P., Engel, A., Goutail, F., Grunow, K., Hendrick, F., Hrechanyy, S., Naujokat, B., Pommereau, J.-P., Van Roozendael, M., Sioris, C., Stroh, F., Weidner, F., and Pfeilsticker, K.: Balloon-borne stratospheric BrO measurements: comparison with Envisat/SCIAMACHY~BrO limb profiles, Atmos. Chem. Phys., 6, 2483–2501, 2006.
Dorf, M., Butz, A., Camy-Peyret, C., Chipperfield, M. P., Kritten, L., and Pfeilsticker, K.: Bromine in the tropical troposphere and stratosphere as derived from balloon-borne BrO~observations, Atmos. Chem. Phys., 8, 7265–7271, 2008.
Fleischmann, O. C., Hartmann, M., Burrows, J. P., and Orphal, J.: New ultraviolet absorption cross-sections of BrO at atmospheric temperatures measured by time-windowing Fourier transform spectroscopy, J. Photoch. Photobio A, 168, 117-132, 2004.
Frankenberg, C., Platt, U., and Wagner, T.: Iterative maximum a posteriori (IMAP)-DOAS for retrieval of strongly absorbing trace gases: Model studies for CH<sub>4</sub> and CO<sub>2</sub> retrieval from near infrared spectra of SCIAMACHY onboard ENVISAT, Atmos. Chem. Phys., 5, 9–22, 2005.
Kühl, S.: Quantifying Stratospheric chlorine chemistry by the satellite spectrometers GOME and SCIAMACHY, PhD Thesis, Universität Heidelberg, Heidelberg, Germany, available at: http://www.ub.uni-heidelberg.de/archiv/5664/, 177~pp.,2005.
Kühl, S., Pu\ck\=ıte, J., Deutschmann, T., Platt, U., and Wagner, T.: SCIAMACHY Limb Measurements of NO<sub>2</sub>, BrO and OClO, Retrieval of vertical profiles: Algorithm, first results, sensitivity and comparison studies, Adv. Space Res., 42, 1747–1764, 2008.
Marquard, L. C., Wagner, T., and Platt, U.: Improved Air Mass Factor Concepts for Scattered Radiation Differential Optical Absorption Spectroscopy of Atmospheric Species, J. Geophys. Res., 105, 1315–1327, 2000.
Mount, G. H., Sanders, R. W., Schemltekopf, A. L., and Solomon, S.: Visible spectroscopy at McMurdo Station, Antarctica, 1 Overview and daily variations of NO<sub>2</sub> and O<sub>3</sub>, austral spring, 1986, J. Geophys. Res., 92, 8320–8328, 1987.
Noxon, J. F.: Nitrogen dioxide in the stratosphere and troposphere measured by ground-based absorption spectroscopy, Science, 189, 547–549, 1975.
Perliski, L. M. and Solomon, S.: On the evaluation of air mass factors for atmospheric near ultra-violet and visible absorption spectroscopy, J. Geophys. Res., 98, 10363–10374, 1993.
Perner, D., Ehhalt, D. H., Pätz, H. W., Platt, U., Röth, E. P., and Volz, A.: OH-radicals in the lower troposphere, Geophys. Res. Lett. 3, 466–468, 1976.
Pfeilsticker, K. and Platt, U.: Airborne measurements during the Arctic stratospheric experiment: Observation of O<sub>3</sub> and NO<sub>2</sub>, Geophys. Res. Lett., 21, 1375–1378, 1994.
Platt, U., Marquard, L., Wagner, T., and Perner, D.: Corrections for zenith scattered light DOAS, Geophys. Res. Lett., 24, 1759–1762, 1997.
Platt, U., Perner, D., and Pätz, H.: Simultaneous measurement of atmospheric CH<sub>2</sub>O, O<sub>3</sub>, and NO<sub>2</sub> by differential optical absorption, J. Geophys. Res., 84, 6329–6335, 1979.
Platt, U. and Perner, D.: Direct measurements of atmospheric HCHO, HONO, O<sub>3</sub>, NO<sub>2</sub>, and SO<sub>2</sub> by differential optical absorption in the near UV, J. Geophys. Res., 85, 7453–7458, 1980.
Platt, U. and Perner, D.: Measurements of atmospheric trace gases by long path differential UV/visible absorption spectroscopy, in: Optical and Laser Remote Sensing, edited by: Killinger, D. K. and Mooradien, A., Springer Series in Optical Sciences, Springer, Berlin, 39, 97–105, 1983.
Platt, U.: Differential Optical Absorption Spectroscopy (DOAS), in: Air Monitoring by Spectroscopic Techniques, edited by: Sigrist, M. W., Chemical Analysis Series, John Wiley, New York, 127, 1994.
Platt, U. and Stutz, J.: Differential Optical Absorption Spectroscopy. Principles and Applications, Series: Physics of Earth and Space Environments, Springer, Heidelberg, 597~pp., doi:10.1007/978-3-540-75776-4, 2008.
Pu\ck\=ıte, J., Kühl, S., Deutschmann, T., Wilms-Grabe, W., Friedeburg, C., Platt, U., and Wagner, T.: Retrieval of stratospheric trace gases from SCIAMACHY limb measurements, Proceedings of the First Atmospheric Science Conference, 8–12~May, ESA/ESRIN, Frascati, Italy, ESA~SP-628, available at: http://earth.esa.int/workshops/atmos2006/participants/1148/paper_proc_Frasc_2.pdf, 2006.
Richter, A.: Absorptionsspektroskopische Messungen stratosphärischer Spurengase über Bremen, 55° N, Ph.D thesis, Inst für Umweltphysik, Univ of Bremen, Bremen, Germany, 1997.
Rodgers, C. D.: Inverse methods for atmospheric sounding, Theory and practice, World Scientific Publishing Co Ltd., Singapore, 2000.
Rozanov, A., Bovensmann, H., Bracher, A., Hrechanyy, S., Rozanov, V., Sinnhuber, M., Stroh, F., and Burrows, J. P.: NO<sub>2</sub> and BrO vertical profile retrieval from SCIAMACHY limb measurements: Sensitivity studies, Adv. Space Res., 36(5), 846–854, doi:10.1016/j.asr.2005.03.013, 2005.
Solomon, S., Schmeltekopf, A. L., and Sanders, R. W.: On the interpretation of zenith sky absorption measurements, J. Geophys. Res., 92, 8311–8319, 1987.
Stutz, J. and Platt, U.: Numerical analysis and error estimation of differential optical absorption spectroscopy measurements with least squares methods, Appl. Optics, 35, 6041–6053, 1996.
Wahner, A., Ravishankara, A., Sander, S., and Friedl, R.: Absorption cross section of BrO between 312 and 385 nm at 298 and 223 K, Chem. Phys. Lett., 152, 507-512, 1988.
Wahner, A., Callies, J., Dorn, H.-P., Platt, U., and Schiller, C.: Near UV atmospheric absorption measurements of column abundances during airborne Arctic stratospheric expedition, January–February~1989: 1 Technique and NO<sub>2</sub> observations, Geophys. Res. Lett., 17, 497-500, 1990.
Wagner, T., Beirle, S., Deutschmann, T., Eigemeier, E., Frankenberg, C., Grzegorski, M., Liu, C., Marbach, T., Platt, U., and Penning de Vries, M.: Monitoring of atmospheric trace gases, clouds, aerosols and surface properties from UV/vis/NIR satellite instruments, J. Opt.-A: Pure Appl. Opt., 10, 104019, doi:10.1088/1464-4258/10/10/1040192008, 2008.
Wilmouth, D. M., Hanisco, T. F., Donahue, N. M., and Anderson, J. G.: Fourier Transform Ultraviolet Spectroscopy of the A$^2\Pi_3/2\leftarrow$X$^2\Pi_3/2$ Transition of BrO, J. Phys. Chem A, 103, 8935–8945, doi:10.1021/jp991651o, 1999.