scholarly journals Tropospheric NO2 Monitoring Using the Multi-Axis Differential Optical Absorption Spectroscopy in Urban Area

2019 ◽  
Vol 9 (4) ◽  
pp. 9
Author(s):  
Marilia Mitidieri Fernandes de Oliveira ◽  
Nelson Francisco Favilla Ebecken ◽  
Jorge Luiz Fernandes de Oliveira ◽  
José Maria de Castro Jr
Keyword(s):  
Optical Absorption ◽  
Urban Area ◽  
Absorption Spectroscopy ◽  
Differential Optical Absorption Spectroscopy ◽  
Optical Absorption Spectroscopy ◽  
Ultraviolet Region ◽  
General Description ◽  
Wide Range ◽  
Tropospheric No2 ◽  
The City

Spectroscopic methods have played an important role in the study of chemical and physical processes related to the composition of the atmosphere and the differential optical absorption spectroscopy (DOAS) has been one of the most powerful methods to measure a wide range of trace gases. The pollutants are identified by their respective ranges of wavelengths that must be previously known. A Passive Differential Optical Absorption Spectroscopy system that uses the ultraviolet region from 400 to 480 nm of the solar radiation is presented. In this research diurnal variation of NO2 was remotely measured by means of MAX-DOAS system which uses multiple viewing angles to monitor pollutant concentrations in urban area at the city of Rio de Janeiro. The instrument was placed on the roof of a building oriented to the center of the city. Tropospheric NO2 amounts are retrieved from the measured spectra using the DOAS technique. In this paper we give a general description of the procedure and present the results from measurements during four days in winter 2017 associated with the prevailing meteorological aspects. These days were characterized by mostly sunny and dry conditions, no convection, periods of medium clouds and clear sky. The tropospheric NO2 slant column densities values are presented and the results are consistent for all three used elevation angles (5º, 10º, and 15º). The results demonstrate the capability and the potential of the MAX-DOAS technique to derive information on spatial distribution of NO2 in an urban environment.

scholarly journals Two-dimensional monitoring of air pollution in Madrid using a Multi-AXis Differential Optical Absorption Spectroscopy two-dimensional (MAXDOAS-2D) instrument

2021 ◽  
Vol 14 (4) ◽  
pp. 2941-2955
Author(s):  
David Garcia-Nieto ◽  
Nuria Benavent ◽  
Rafael Borge ◽  
Alfonso Saiz-Lopez
Keyword(s):  
Air Quality ◽  
Optical Absorption ◽  
Absorption Spectroscopy ◽  
Urban Areas ◽  
Spatial Information ◽  
Differential Optical Absorption Spectroscopy ◽  
Optical Absorption Spectroscopy ◽  
Two Dimensional ◽  
Inversion Algorithm ◽  
The City

Abstract. Trace gases play a key role in the chemistry of urban atmospheres. Therefore, knowledge about their spatial distribution is needed to fully characterize air quality in urban areas. Using a new Multi-AXis Differential Optical Absorption Spectroscopy two-dimensional (MAXDOAS-2D) instrument, along with an inversion algorithm (bePRO), we report the first two-dimensional maps of nitrogen dioxide (NO2) and nitrous acid (HONO) concentrations in the city of Madrid, Spain. Measurements were made during 2 months (6 May–5 July 2019), and peak mixing ratios of 12 and 0.7 ppbv (parts per billion by volume) for NO2 and HONO, respectively, were observed in the early morning in the southern part of the downtown area. We found good general agreement between the MAXDOAS-2D mesoscale observations – which provide a typical spatial range of a few kilometers – and the in situ measurements provided by Madrid's air quality monitoring stations. In addition to vertical profiles, we studied the horizontal gradients of NO2 in the surface layer by applying the different horizontal light path lengths in the two spectral regions included in the NO2 spectral analysis: ultraviolet (UV, at 360 nm) and visible (VIS, 477 nm). We also investigate the sensitivity of the instrument to infer vertically distributed information on aerosol extinction coefficients and discuss possible future ways to improve the retrievals. The retrieval of two-dimensional distributions of trace gas concentrations reported here provides valuable spatial information for the study of air quality in the city of Madrid.

scholarly journals Retrieval interval mapping: a tool to visualize the impact of the spectral retrieval range on differential optical absorption spectroscopy evaluations

2013 ◽  
Vol 6 (2) ◽  
pp. 275-299 ◽  
Author(s):  
L. Vogel ◽  
H. Sihler ◽  
J. Lampel ◽  
T. Wagner ◽  
U. Platt
Keyword(s):  
Optical Absorption ◽  
Wavelength Range ◽  
Absorption Spectroscopy ◽  
Trace Gases ◽  
Differential Optical Absorption Spectroscopy ◽  
General Nature ◽  
Optical Absorption Spectroscopy ◽  
Wide Range ◽  
The Impact ◽  
Optimal Retrieval

Abstract. Remote sensing via differential optical absorption spectroscopy (DOAS) has become a standard technique to identify and quantify trace gases in the atmosphere. Due to the wide range of measurement conditions, atmospheric compositions and instruments used, a specific challenge of a DOAS retrieval is to optimize the retrieval parameters for each specific case and particular trace gas of interest. Of these parameters, the retrieval wavelength range is one of the most important ones. Although for many trace gases the overall dependence of common DOAS retrieval on the evaluation wavelength interval is known, a systematic approach for finding the optimal retrieval wavelength range and quantitative assessment is missing. Here we present a novel tool to visualize the effect of different evaluation wavelength ranges. It is based on mapping retrieved column densities in the retrieval wavelength space and thus visualizing the consequences of different choices of spectral retrieval ranges caused by slightly erroneous absorption cross sections, cross correlations and instrumental features. Based on the information gathered, an optimal retrieval wavelength range may be determined systematically. The technique is demonstrated using examples of a theoretical study of BrO retrievals for stratospheric BrO and BrO measurements in volcanic plumes. However, due to the general nature of the tool, it is applicable to any type of DOAS retrieval (active or passive).

scholarly journals Total Ozone Columns from the Environmental Trace Gases Monitoring Instrument (EMI) Using the DOAS Method

2021 ◽  
Vol 13 (11) ◽  
pp. 2098
Author(s):  
Yuanyuan Qian ◽  
Yuhan Luo ◽  
Fuqi Si ◽  
Haijin Zhou ◽  
Taiping Yang ◽  
...  
Keyword(s):  
Optical Absorption ◽  
Absorption Spectroscopy ◽  
Total Ozone ◽  
Scattered Light ◽  
Trace Gases ◽  
Rapid Change ◽  
Differential Optical Absorption Spectroscopy ◽  
Optical Absorption Spectroscopy ◽  
Monitoring Instrument ◽  
Monthly Average

Global measurements of total ozone are necessary to evaluate ozone hole recovery above Antarctica. The Environmental Trace Gases Monitoring Instrument (EMI) onboard GaoFen 5, launched in May 2018, was developed to measure and monitor the global total ozone column (TOC) and distributions of other trace gases. In this study, some of the first global TOC results of the EMI using the differential optical absorption spectroscopy (DOAS) method and validation with ground-based TOC measurements and data derived from Ozone Monitoring Instrument (OMI) and TROPOspheric Monitoring Instrument (TROPOMI) observations are presented. Results show that monthly average EMI TOC data had a similar spatial distribution and a high correlation coefficient (R ≥ 0.99) with both OMI and TROPOMI TOC. Comparisons with ground-based measurements from the World Ozone and Ultraviolet Radiation Data Centre also revealed strong correlations (R > 0.9). Continuous zenith sky measurements from zenith scattered light differential optical absorption spectroscopy instruments in Antarctica were also used for validation (R = 0.9). The EMI-derived observations were able to account for the rapid change in TOC associated with the sudden stratospheric warming event in October 2019; monthly average TOC in October 2019 was 45% higher compared to October 2018. These results indicate that EMI TOC derived using the DOAS method is reliable and has the potential to be used for global TOC monitoring.

scholarly journals Satellite monitoring of different vegetation types by differential optical absorption spectroscopy (DOAS) in the red spectral range

2007 ◽  
Vol 7 (1) ◽  
pp. 69-79 ◽  
Author(s):  
T. Wagner ◽  
S. Beirle ◽  
T. Deutschmann ◽  
M. Grzegorski ◽  
U. Platt
Keyword(s):  
Optical Absorption ◽  
Absorption Spectroscopy ◽  
Spectral Range ◽  
Near Infrared ◽  
Vegetation Type ◽  
Differential Optical Absorption Spectroscopy ◽  
Trace Gas ◽  
Satellite Monitoring ◽  
Optical Absorption Spectroscopy ◽  
Vegetation Types

Abstract. A new method for the satellite remote sensing of different types of vegetation and ocean colour is presented. In contrast to existing algorithms relying on the strong change of the reflectivity in the red and near infrared spectral region, our method analyses weak narrow-band (few nm) reflectance structures (i.e. "fingerprint" structures) of vegetation in the red spectral range. It is based on differential optical absorption spectroscopy (DOAS), which is usually applied for the analysis of atmospheric trace gas absorptions. Since the spectra of atmospheric absorption and vegetation reflectance are simultaneously included in the analysis, the effects of atmospheric absorptions are automatically corrected (in contrast to other algorithms). The inclusion of the vegetation spectra also significantly improves the results of the trace gas retrieval. The global maps of the results illustrate the seasonal cycles of different vegetation types. In addition to the vegetation distribution on land, they also show patterns of biological activity in the oceans. Our results indicate that improved sets of vegetation spectra might lead to more accurate and more specific identification of vegetation type in the future.

Sign in / Sign up

Export Citation Format

Share Document