Differential Optical Absorption Spectroscopy, Air Monitoring by

Platt, U.

doi:10.1002/9780470027318.a0706

Cited by 359 publications

(476 citation statements)

References 76 publications

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“…The spectrometer's optics, detector, and electronics are built into a unit of 8.91 x 6.33 x 34.4 cm dimensions, and are powered via the USB-port of a laptop computer, which also supports data transfer . Details on the characteristics of the mini-UV spectrometer and on the DOAS technique are discussed elsewhere (Platt, 1994;Edmonds et al, 2003).…”

Section: Mini-uv Spectrometermentioning

confidence: 99%

“…A commercial UV spectrometer (here called Mini-UV Spectrometer or MUSe) and the principles of Differential Optical Absorption Spectroscopy (DOAS) form the basis of the technique (Platt, 1994), similar to that used in previous experiments McGonigle et al, 2002;Edmonds et al, 2003). UV light from the Sun, scattered by aerosols and molecules in the atmosphere, is collected by a telescope.…”

Section: Mini-uv Spectrometermentioning

confidence: 99%

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SO2 loss rates in the plume emitted by Soufrière Hills volcano, Montserrat

Rodríguez

Watson

Edmonds

et al. 2008

Journal of Volcanology and Geothermal Research

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Abstract. To improve interpretation of volcanic SO 2 flux data, it is necessary to quantify and understand reactions involving SO 2 in volcanic plumes. SO 2 is lost in volcanic plumes through a number of mechanisms. Here we report SO 2 measurements made with miniature ultraviolet spectrometers at Soufrière Hills volcano, Montserrat; a low altitude volcano (~1000 m above sea level) whose plume entrains humid marine air in the planetary boundary layer. Traverses very near (<400 m) beneath the ash-free plume were made at various distances from the source (from ~2 km to ~16 km), thereby spanning plume ages of about 6 to 35 minutes with minimal attenuation. We find average SO 2 loss rates of ~10 -4 s -1 (e-folding time of ~2.78 hours), slightly lower than estimated previously for Soufrière Hills. These are in the fast end of the range of loss rates measured at other volcanoes (10 -3 -10 -7 s -1 , e-folding times of 0.28-2778 hr), indicating that Montserrat plumes have short SO 2 lifetimes. This work is more detailed and precise than previous work and is likely to represent the general case at Montserrat. SO 2 flux measurements made >2 km downwind from Soufrière Hills volcano significantly underestimate atsource SO 2 emission rates, on the order of 70-146%, when not accounting for the decay rate. Similar SO 2 loss is likely to occur in plumes from other tropical low altitude volcanoes under conditions of high relative humidity (~20% of active volcanoes worldwide). These results suggest that the global volcanic SO 2 emission rate may be underestimated as the estimates are based on measurements taken downwind of volcanoes, by which time significant loss of SO 2 may have taken place. The loss rates calculated here could be used, in conjunction with downwind SO 2 fluxes, to estimate atsource SO 2 emission rates from volcanoes with similar environmental conditions to those at Soufrière Hills volcano.3

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Section: Mini-uv Spectrometermentioning

confidence: 99%

Section: Mini-uv Spectrometermentioning

confidence: 99%

SO2 loss rates in the plume emitted by Soufrière Hills volcano, Montserrat

Rodríguez

Watson

Edmonds

et al. 2008

Journal of Volcanology and Geothermal Research

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“…Detailed descriptions of the algorithm for the standard OMI NO 2 data product are given in Boersma et al [2002], Bucsela et al [2006], . In brief, the standard algorithm uses the Differential Optical Absorption Spectroscopy (DOAS) technique [Platt, 1994] to determine the slant column densities by nonlinear least squares fitting in the 415 -465 nm window. The slant column represents the integrated abundance of NO 2 along the average photon path through the atmosphere.…”

Section: Omi Tropospheric No 2 Columnsmentioning

confidence: 99%

Ground‐level nitrogen dioxide concentrations inferred from the satellite‐borne Ozone Monitoring Instrument

et al. 2008

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[1] We present an approach to infer ground-level nitrogen dioxide (NO 2 ) concentrations by applying local scaling factors from a global three-dimensional model (GEOS-Chem) to tropospheric NO 2 columns retrieved from the Ozone Monitoring Instrument (OMI) onboard the Aura satellite. Seasonal mean OMI surface NO 2 derived from the standard tropospheric NO 2 data product (Version 1.0.5, Collection 3) varies by more than two orders of magnitude (<0.1->10 ppbv) over North America. Two ground-based data sets are used to validate the surface NO 2 estimate and indirectly validate the OMI tropospheric NO 2 retrieval: photochemical steady-state (PSS) calculations of NO 2 based on in situ NO and O 3 measurements, and measurements from a commercial chemiluminescent NO 2 analyzer equipped with a molybdenum converter. An interference correction algorithm for the latter is developed using laboratory and field measurements and applied using modeled concentrations of the interfering species. The OMI-derived surface NO 2 mixing ratios are compared with an in situ surface NO 2 data obtained from the U.S. Environmental Protection Agency's Air Quality System (AQS) and Environment Canada's National Air Pollution Surveillance (NAPS) network for 2005 after correcting for the interference in the in situ data. The overall agreement of the OMI-derived surface NO 2 with the corrected in situ measurements and PSS-NO 2 is À11-36%. A larger difference in winter/spring than in summer/fall implies a seasonal bias in the OMI NO 2 retrieval. The correlation between the OMI-derived surface NO 2 and the ground-based measurements is significant (correlation coefficient up to 0.86) with a tendency for higher correlations in polluted areas. The satellite-derived data base of ground level NO 2 concentrations could be valuable for assessing exposures of humans and vegetation to NO 2 , supplementing the capabilities of the ground-based networks, and evaluating air quality models and the effectiveness of air quality control strategies.Citation: Lamsal, L. N., R.

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“…: VALIDATION OF OSIRIS NO2 PROFILES ECD, (sometimes referred to as slant column densities) are calculated using Differential Optical Absorption Spectroscopy (DOAS) [Platt, 1994]. The DOAS step is performed to reduce the sensitivity to phenomena that vary slowly with wavelength such as aerosol (Mie) scattering.…”

Section: Doas Stepmentioning

confidence: 99%

“…[4] Haley et al [2004] describe how NO 2 and O 3 can be successfully retrieved from OSIRIS limb-scatter measurements in the stratosphere using a combination of Differential Optical Absorption Spectroscopy (DOAS) [Platt, 1994] and Optimal Estimation (OE) [Rodgers, 2000]. OSIRIS provides a unique data set of NO 2 with a slightly more than hemispheric coverage and a vertical resolution of about 2 km between 15 and 40 km.…”

Section: Introductionmentioning

confidence: 99%

Validation of Odin/OSIRIS stratospheric NO₂ profiles

Brohede¹,

Haley²,

McLinden³

et al. 2007

J. Geophys. Res.

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[1] This paper presents the validation study of stratospheric NO 2 profiles retrieved from Odin/OSIRIS measurements of limb-scattered sunlight (version 2.4). The Optical Spectrograph and Infrared Imager System (OSIRIS) NO 2 data set is compared to coincident solar occultation measurements by the Halogen Occultation Experiment (HALOE), Stratospheric Aerosol and Gas Experiment (SAGE) II, SAGE III, and Polar Ozone and Aerosol Measurement (POAM) III during the 2002-2004 period. Comparisons with seven Systeme d'Analyse par Observation Zenithal (SAOZ) balloon measurements are also presented. All comparisons show good agreement, with differences, both random and systematic, of less than 20% between 25 km and 35 km. Inconsistencies with SAGE III below 25 km are found to be caused primarily by diurnal effects from varying NO 2 concentrations along the SAGE III line-of-sight. On the basis of the differences, the OSIRIS random uncertainty is estimated to be 16% between 15 km and 25 km, 6% between 25 km and 35 km, and 9% between 35 km and 40 km. The estimated systematic uncertainty is about 22% between 15 and 25 km, 11-21% between 25 km and 35 km, and 11-31% between 35 km and 40 km. The uncertainties for AM (sunrise) profiles are generally largest and systematic deviations are found to be larger at equatorial latitudes. The results of this validation study show that the OSIRIS NO 2 profiles are well behaved, with reasonable uncertainty estimates between 15 km and 40 km. This unique NO 2 data set, with more than hemispheric coverage and high vertical resolution will be of particular interest for studies of nitrogen chemistry in the middle atmosphere, which is closely linked to ozone depletion.

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Differential Optical Absorption Spectroscopy, Air Monitoring by

Cited by 359 publications

References 76 publications

SO2 loss rates in the plume emitted by Soufrière Hills volcano, Montserrat

SO2 loss rates in the plume emitted by Soufrière Hills volcano, Montserrat

Ground‐level nitrogen dioxide concentrations inferred from the satellite‐borne Ozone Monitoring Instrument

Validation of Odin/OSIRIS stratospheric NO₂ profiles

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Differential Optical Absorption Spectroscopy, Air Monitoring by

Cited by 359 publications

References 76 publications

SO2 loss rates in the plume emitted by Soufrière Hills volcano, Montserrat

SO2 loss rates in the plume emitted by Soufrière Hills volcano, Montserrat

Ground‐level nitrogen dioxide concentrations inferred from the satellite‐borne Ozone Monitoring Instrument

Validation of Odin/OSIRIS stratospheric NO2 profiles

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Validation of Odin/OSIRIS stratospheric NO₂ profiles