Abstract
There is widespread use of passive remote sensing techniques to quantify trace gas column densities in volcanic plumes utilizing scattered sunlight as a light source. Examples include passive DOAS, COSPEC, and the SO2 camera. In order to calculate trace gas concentrations or volcanic emission fluxes, knowledge about the optical path through the plume is necessary. In the past, a straight photon path through the plume has always been assumed although it was known that this is not always true. Here we present the results of model studies conducted specifically to quantify the effects of realistic radiative transfer in and around volcanic plumes on ground-based remote sensing measurements of SO2. The results show that measurements conducted without additional information on average photon paths can be inaccurate under certain conditions, with possible errors spanning more than an order of magnitude. Both over and underestimation of the true column density can occur. Actual errors depend on parameters such as distance between instrument and plume, plume SO2 concentration, plume aerosol load, as well as aerosol conditions in the ambient atmosphere. As an example, a measurement conducted with an SO2 camera is discussed, the results of which can only be correctly interpreted if realistic radiative transfer is considered. Finally, a method is presented which for the first time allows the retrieval of actual average photon paths in spectroscopic (i.e. DOAS) measurements of adequate resolution. By allowing for a wavelength dependent column density during the evaluation of DOAS measurements, we show how radiative transfer effects can be corrected using information inherently available in the measured spectra, thus greatly enhancing the accuracy of DOAS measurements of volcanic emissions.
Similar content being viewed by others
Notes
Trace Gas RAdiative Transfer Monte Carlo (Y)Implementation
The units molecules/cm2 where converted to ppm m assuming standard pressure and a temperature of 20°C throughout the text: 1 ppm m = 2.5 × 1015 molecules/cm2
References
Bluth GJS, Shannon JM, Watson IM, Prata AJ, Realmuto VJ (2007) Development of an ultra-violet digital camera for volcanic SO2 imaging. J Volcanol Geotherm Res 161:47–56
Bobrowski N (2005) Volcanic gas studies by MAX-DOAS. PhD thesis, University of Heidelberg, Heidelberg
Bobrowski N, Hönninger G, Lohberger F, Platt U (2006) IDOAS: A new monitoring technique to study the 2D distribution of volcanic gas emissions. J Volcanol Geotherm Res 150:329–338
Bogumil K, Orphal J, Homan T, Voigt S, Spietz P, Fleischmann O, Vogel A, Hartmann M, Bovensmann H, Frerick J, Burrows J (2003) Measurements of molecular absorption spectra with the SCIAMACHY pre-flight model: instrument characterization and reference data for atmospheric remote-sensing in the 230–2380 nm region. J Photochem Photobiol A: Chem 157:167–184
Deutschmann T (2008) Atmospheric radiative transfer modelling with Monte Carlo methods. Diploma thesis, University of Heidelberg, Heidelberg
Edmonds M, Herd RA, Galle B, Oppenheimer C (2003) Automated, high time-resolution measurements of SO2 flux at Soufrière Hills Volcano, Montserrat. Bull Volcanol 65:578–586
Elias T, Sutton AJ, Oppenheimer C, Horton KA, Garbeil H, Tsanev V, McGonigle AJS, Williams-Jones G (2006) Comparison of COSPEC and two miniature ultraviolet spectrometer systems for SO2 measurements using scattered sunlight. Bull Volcanol 68:313–322
Erle F, Pfeilsticker K, Platt U (1995) On the influence of tropospheric clouds on zenith-scattered-light measurements of stratospheric species. Geophys Res Lett 22:2725–2728
Francis P, Burton MR, Oppenheimer C (1998) Remote measurements of volcanic gas compositions by solar occultation spectroscopy. Nature 396:567–570
Frederick JE, Abrams RB (1981) The surface albedo of the earth in the near ultraviolet (330–340 nm). Remote Sens Environ 11:337–347
Frieß U, Monks PS, Remedios JJ, Rozanov A, Sinreich R, Wagner T, Platt U (2006) MAX-DOAS O4 measurements: A new technique to derive information on atmospheric aerosols: 2. Modeling studies. J Geophys Res 111:D14203. doi:10.1029/2005JD006618
Galle B, Oppenheimer C, Geyer A, McGonigle AJS, Edmonds M, Horrocks L (2003) A miniaturized ultraviolet spectrometer for remote sensing of SO2 fluxes: a new tool for volcano surveillance. J Volcanol Geotherm Res 119:241–254
Goody RM, Young YL (1989) Atmospheric radiation (theoretical basis). Oxford University Press, Oxford
Henyey L, Greenstein J (1941) Diffuse radiation in the galaxy. Astrophys J 93:70–83
Irie H, Kanaya Y, Akimoto H, Iwabuchi H, Shimizu A, Aoki K (2008) First retrieval of tropospheric aerosol profiles using MAX-DOAS and comparison with lidar and sky radiometer measurements. Atmos Chem Phys 8:341–350
Kern C, Sihler H, Vogel L, Rivera C, Herrera M, Platt U (2008) Halogen oxide measurements at Masaya volcano, Nicaragua using active long path differential optical absorption spectroscopy. Bull Volcanol. doi:10.1007/s00445-008-0252-8
Kick F (2008) A UV camera for the measurement of atmospheric trace gas distributions (translated from German). Undergraduate thesis, University of Heidelberg, Heidelberg
Kudo R, Uchiyama A, Yamazaki A, Kobayashi E, Nishizawa T (2008) Retrieval of aerosol single-scattering properties from diffuse and direct irradiances: Numerical studies. J Geophys Res 113:D09204. doi:10.1029/2007JD009239
Li X, Brauers T, Shao M, Garland RM, Wagner T, Deutschmann T, Wahner A (2008) MAX-DOAS measurements in southern China: 1. automated aerosol profile retrieval using oxygen dimers absorptions. Atmos Chem Phys Discuss 8:17661–17690
Liu H, Pinker RT, Chin M, Holben B, Remer L (2008) Synthesis of information on aerosol optical properties. J Geophys Res 113:D07206. doi:10.1029/2007JD008735
Louban I, Bobrowski N, Rouwet D, Inguaggiato S, Platt U (2009) Imaging DOAS for volcanological applications. Bull Volcanol. doi:10.1007/s00445-008-0262-6
Marquard LC, Wagner T, Platt U (2000) Improved air mass factor concepts for scattered radiation differential optical absorption spectroscopy of atmospheric species. J Geophys Res 105:1315–1327
Martin D, Ardouin B, Bergametti G, Carbonelle J, Faivre-Pierret R, Lambert G, Le Cloarec MF, Sennequier G (1986) Geochemistry of sulfur in Mount Etna plume. J Geophys Res 91:12249–12254
McGonigle AJS, Oppenheimer C, Galle B, Mather TA, Pyle DM (2002) Walking traverse and scanning DOAS measurements of volcanic gas emsission rates. Geophys Res Lett 29:1985. doi:10.1029/2002GL015827
McGonigle AJS, Delmelle P, Oppenheimer C, Tsanev VI, Delfosse T, Horton H, Williams-Jones G, Mather TA (2004) SO2 depletion in tropospheric volcanic plumes. Geophys Res Lett 31:L13201. doi:10.1029/2004GL019990
McGonigle AJS, Inguaggiato S, Aiuppa A, Hayes AR, Oppenheimer C (2005) Accurate measurement of volcanic SO2 flux: determination of plume transport speed and integrated SO2 concentration with a single device. Geochem Geophys Geosyst 6:Q02003. doi:10.1029/2004-GC000845
Millán MM (1980) Remote sensing of air pollutants. A study of some atmospheric scattering effects. Atmos Environ 14:1241–1253
Moffat AJ, Millán MM (1971) The applications of optical correlation techniques to the remote sensing of SO2 plumes using sky light. Atmos Environ 5:677–690
Mori T, Burton MR (2006) The SO2 camera: a simple, fast and cheap method for ground-based imaging of SO2 in volcanic plumes. Geophys Res Lett 33:L24804. doi:10.1029/2006GL027916
Mori T, Mori T, Kazahaya K, Ohwada M, Hirabayashi J, Yoshikawa S (2006) Effect of UV scattering on SO2 emission rate measurements. Geophys Res Lett 33:L17315. doi:10.1029/2006GL026285
Ogren JA, Charlson RJ, Radke LF, Domonkos SK (1981) Absorption of visible radiation by aerosols in the volcanic plume of Mount St. Helens. Science 211:834–836
Oppenheimer C, Francis P, Burton MR, Maciejewski AJH, Boardman L (1998a) Remote measurement of volcanic gases by Fourier transform infrared spectroscopy. Appl Phys B 67:505–515
Oppenheimer C, Francis P, Stix J (1998b) Depletion rates of sulfur dioxide in tropospheric volcanic plumes. Geophys Res Lett 25:2671–2674
Perliski LM, Solomon S (1993) On the evaluation of air mass factors for atmospheric near-ultraviolet and visible absorption spectroscopy. J Geophys Res 98:10363–10374
Pfeilsticker K, Erle F, Funk O, Marquard L, Wagner T, Platt U (1998) Optical path modifications due to tropospheric clouds: implications for zenith sky measurements of stratospheric gases. J Geophys Res 103:25323–25335
Platt U, Stutz J (2008) Differential Optical Absorption Spectroscopy — principles and applications. Springer, Berlin Heidelberg New York
Rodríguez LA, Watson IM, Edmonds M, Ryan G, Hards V, Oppenheimer C, Bluth GJS (2008) SO2 loss rates in the plume emitted by Soufrière Hills volcano, Montserrat. J Volcanol Geotherm Res 173:135–147
Sinreich R, Friess U, Wagner T, Platt U (2005) Multi axis differential optical absorption spectrosocopy (MAX-DOAS) of gas and aerosol distributions. Faraday Discuss 130:132–164
Solomon S, Schmeltekopf AL, Sanders RW (1987) On the interpretation of zenith sky absorption measurements. J Geophys Res 92:8311–8319
Sommer T (2008) Direct sun light measurements of volcanic plumes using differential optical absorption spectroscopy. Diploma thesis, University of Heidelberg, Heidelberg
Spinetti C, Buongiornio MF, Lombardo V, Merucci L (2003) Aerosol optical thickness of Mt. Etna volcanic plume retrieved by means of the Airborne Multispectral Imaging Spectrometer (MIVIS). Ann Geophys Italy 46:439–449
Stoiber RE, Jepsen A (1973) Sulfur dioxide contributions to the atmosphere by volcanoes. Science 182:577–578
Stoiber RE, Malinconico LL, Williams SN (1983) Use of the correlation spectrometer at volcanoes. In: Tazieff H, Sabroux JC (eds) Forecasting volcanic events. Elsevier, Amsterdam, pp 424–444
Veitel H, Funk O, Kurz C, Platt U, Pfeilsticker K (1998) Geometrical path length probability density functions of the skylight transmitted by midlatitude cloudy skies: Some case studies. Geophys Res Lett 25:3355–3358
Wagner T, Dix B, von Friedeburg C, Friess U, Sanghavi S, Sinreich R, Platt U (2004) MAX-DOAS O4 measurements: A new technique to derive information on atmospheric aerosols — Principles and information content. J Geophys Res 109:D22205. doi:10.1029/2004JD004904
Wagner T, Erle F, Marquard L, Otten C, Pfeilsticker K, Senne T, Stutz J, Platt U (1998) Cloudy sky photon path lengths as derived from DOAS observations. J Geophys Res 103:25307–25321
Wagner T, Burrows JP, Deutschmann T, Dix B, von Friedeburg C, Frieß U, Hendrick F, Heue K-P, Irie H, Iwabuchi H, Kanaya Y, Keller J, McLinden CA, Oetjen H, Palazzi E, Petritoli A, Platt U, Postylyakov O, Pukite J, Richter A, van Roozendael M, Rozanov A, Rozanov V, Sinreich R, Sanghavi S, Wittrock F (2007) Comparison of box-air-mass-factors and radiances for Multiple-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) geometries calculated from different UV/visible radiative transfer models. Atmos Chem Phys 7:1809–1833
Williams-Jones G, Horton KA, Elias T, Garbeil H, Mouginis-Mark PJ, Sutton AJ, Harris AJL (2006) Accurately measuring volcanic plume velocity with multiple UV spectrometers. Bull Volcanol 68:328–332
Acknowledgements
The authors would like to thank Nicole Bobrowski, Mike Burton, Tommaso Caltabiano, Salvatore Inguaggiato and Fabio Vita for their assistance during the measurement campaign at Mt. Etna in July 2008. We also gratefully acknowledge the Network for Observation of Volcanic and Atmospheric Change (NOVAC) (European Union FP6 Research Program) for providing funding for this study. Finally, thanks to Matt Watson, Pierre Delmelle, and an anonymous reviewer for their help in substantially improving this work.
Author information
Authors and Affiliations
Corresponding authors
Additional information
Editorial responsibility: P. Delmelle
Rights and permissions
About this article
Cite this article
Kern, C., Deutschmann, T., Vogel, L. et al. Radiative transfer corrections for accurate spectroscopic measurements of volcanic gas emissions. Bull Volcanol 72, 233–247 (2010). https://doi.org/10.1007/s00445-009-0313-7
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s00445-009-0313-7