Retrieving vertical profile of aerosol extinction by multi-axis differential optical absorption spectroscopy

Abstract. Ground-based multi-axis differential optical absorption spectroscopy (MAX-DOAS) measurements of aerosols and tropospheric nitrogen dioxide (NO2) were carried out in Uccle (50.8∘ N, 4.35∘ E), Brussels, during 1 year from March 2018 until March 2019. The instrument was operated in both the UV and visible wavelength ranges in a dual-scan configuration consisting of two sub-modes: (1) an elevation scan in a fixed viewing azimuthal direction (the so-called main azimuthal direction) pointing to the northeast and (2) an azimuthal scan in a fixed low elevation angle (2∘). By applying a vertical profile inversion algorithm in the main azimuthal direction and a parameterization technique in the other azimuthal directions, near-surface NO2 volume mixing ratios (VMRs) and vertical column densities (VCDs) were retrieved in 10 different azimuthal directions. The dual-scan MAX-DOAS dataset allows for partly resolving the horizontal distribution of NO2 around the measurement site and studying its seasonal variations. Furthermore, we show that measuring the tropospheric NO2 VCDs in different azimuthal directions improves the spatial colocation with measurements from the Sentinel-5 Precursor (S5P), leading to a reduction of the spread in validation results. By using NO2 vertical profile information derived from the MAX-DOAS measurements, we also resolve a systematic underestimation in S5P NO2 data due to the use of inadequate a priori NO2 profile shape data in the satellite retrieval.

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Research of Aerosol Extinction Inverted with Look-Up Table Method Based on Multi-Axis Differential Optical Absorption Spectroscopy

Acta Optica Sinica ◽

10.3788/aos201333.0601002 ◽

2013 ◽

Vol 33 (6) ◽

pp. 0601002 ◽

Cited By ~ 2

Author(s):

吴丰成 Wu Fengcheng ◽

谢品华 Xie Pinhua ◽

李昂 Li Ang ◽

司福祺 Si Fuqi ◽

徐晋 Xu Jin ◽

...

Keyword(s):

Optical Absorption ◽

Absorption Spectroscopy ◽

Differential Optical Absorption Spectroscopy ◽

Optical Absorption Spectroscopy ◽

Aerosol Extinction ◽

Table Method ◽

Look Up Table

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Aerosol Extinction Retrieved with Optical Estimation Algorithm Based on Multi-axis Differential Optical Absorption Spectroscopy

ACTA PHOTONICA SINICA ◽

10.3788/gzxb20184707.0701002 ◽

2018 ◽

Vol 47 (7) ◽

pp. 701002 ◽

Cited By ~ 1

Author(s):

牟福生 MOU Fu-sheng ◽

雒静 LUO Jing ◽

李素文 LI Su-wen ◽

王家伟 WANG Jia-wei ◽

施瑞瑞 SHI Rui-rui ◽

...

Keyword(s):

Optical Absorption ◽

Absorption Spectroscopy ◽

Estimation Algorithm ◽

Differential Optical Absorption Spectroscopy ◽

Optical Absorption Spectroscopy ◽

Aerosol Extinction

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A rapid method to derive horizontal distributions of trace gases and aerosols near the surface using multi-axis differential optical absorption spectroscopy

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-6-8129-2013 ◽

2013 ◽

Vol 6 (5) ◽

pp. 8129-8186

Author(s):

Y. Wang ◽

A. Li ◽

P. H. Xie ◽

T. Wagner ◽

H. Chen ◽

...

Keyword(s):

Optical Absorption ◽

Rapid Method ◽

Absorption Spectroscopy ◽

Trace Gases ◽

Elevation Angle ◽

Differential Optical Absorption Spectroscopy ◽

Optical Absorption Spectroscopy ◽

Aerosol Extinction ◽

Correction Factors ◽

Light Path

Abstract. We apply a novel experimental procedure for the rapid measurement of the average volume mixing ratios (VMRs) and horizontal distributions of trace gases such as NO2, SO2, and HCHO in the boundary layer, which was recently suggested by Sinreich et al. (2013). The method is based on two-dimensional scanning multi-axis differential optical absorption spectroscopy (MAX-DOAS). It makes use of two facts (Sinreich et al. 2013): First, the light path for observations at 1° elevation angle traverses mainly air masses located close to the ground (typically < 200 m). Second, the light path length can be calculated using the simultaneous measured absorption of the oxygen dimer O4. Thus, the average value of the trace gas VMR in the atmospheric layer between the surface and the altitude, for which this observation was sensitive, can be calculated. Compared to the originally proposed method, we introduce several important modifications and improvements: We apply the method only to measurements at 1° elevation angles, for which the uncertainties are especially small. Using only 1 elevation angle also allows an increased temporal resolution. We apply correction factors (and their uncertainties) as function of the simultaneously modelled O4 absorption. In this way the correction factors can be directly determined according to the measured O4 dAMF. Finally, the method is extended to trace gases analysed at other wavelengths and also to the retrieval of the aerosol extinction. Depending on the atmospheric visibility, the typical uncertainty of the results ranges from about 15 to 30%. We apply the rapid method to observations of a newly developed ground-based multifunctional passive differential optical absorption spectroscopy (GM-DOAS) instrument in the north-west outskirt near Hefei City in China. We report NO2, SO2, and HCHO VMRs and aerosol extinction for four azimuth angles and compare these results with those from simultaneous long-path DOAS observations. Good agreement is found (squares of the correlation coefficients for NO2, SO2, and HCHO were 0.92, 0.84, and 0.59, respectively), verifying the reliability of this novel method. Similar agreement is found for the comparison of the aerosol extinction with results from visibility meters. Future studies may conduct measurements using a larger number of azimuth angles to increase the spatial resolution.

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A rapid method to derive horizontal distributions of trace gases and aerosols near the surface using multi-axis differential optical absorption spectroscopy

Atmospheric Measurement Techniques ◽

10.5194/amt-7-1663-2014 ◽

2014 ◽

Vol 7 (6) ◽

pp. 1663-1680 ◽

Cited By ~ 17

Author(s):

Y. Wang ◽

A. Li ◽

P. H. Xie ◽

T. Wagner ◽

H. Chen ◽

...

Keyword(s):

Optical Absorption ◽

Rapid Method ◽

Absorption Spectroscopy ◽

Trace Gases ◽

Elevation Angle ◽

Differential Optical Absorption Spectroscopy ◽

Optical Absorption Spectroscopy ◽

Aerosol Extinction ◽

Light Path ◽

North West

Abstract. We apply a novel experimental procedure for the rapid measurement of the average volume mixing ratios (VMRs) and horizontal distributions of trace gases such as NO2, SO2, and HCHO in the boundary layer, which was recently suggested by Sinreich et al. (2013). The method is based on two-dimensional scanning multi-axis differential optical absorption spectroscopy (MAX-DOAS). It makes use of two facts (Sinreich et al., 2013): first, the light path for observations at 1° elevation angle traverses mainly air masses located close to the ground (typically < 200 m); second, the light path length can be calculated using the simultaneous measured absorption of the oxygen dimer O4. Thus, the average value of the trace gas VMR in the atmospheric layer between the surface and the particular altitude, for which this observation was sensitive, can be calculated. Compared to the originally proposed method, we introduce several important modifications and improvements: We apply the method only to measurements at 1° elevation angle (besides zenith view), for which the uncertainties of the retrieved values of the VMRs and surface extinctions are especially small. Using only 1° elevation angle for off-axis observation also allows an increased temporal resolution. We determine (and apply) correction factors (and their uncertainties) directly as function of the measured O4 absorption. Finally, the method is extended to trace gases analysed at other wavelengths and also to the retrieval of aerosol extinction. Depending on atmospheric visibility, the typical uncertainty of the results ranges from about 20% to 30%. We apply the rapid method to observations of a newly-developed ground-based multifunctional passive differential optical absorption spectroscopy (GM-DOAS) instrument in the north-west outskirts near Hefei in China. We report NO2, SO2, and HCHO VMRs and aerosol extinction for four azimuth angles and compare these results with those from simultaneous long-path DOAS observations. Good agreement is found (squares of the correlation coefficients for NO2, SO2, and HCHO were 0.92, 0.85, and 0.60, respectively), verifying the reliability of this novel method. Similar agreement is found for the comparison of the aerosol extinction with results from visibility meters. Future studies may conduct measurements using a larger number of azimuth angles to increase the spatial resolution.

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Retrieval and evaluation of tropospheric-aerosol extinction profiles using multi-axis differential optical absorption spectroscopy (MAX-DOAS) measurements over Athens, Greece

Atmospheric Measurement Techniques ◽

10.5194/amt-14-749-2021 ◽

2021 ◽

Vol 14 (1) ◽

pp. 749-767

Author(s):

Myrto Gratsea ◽

Tim Bösch ◽

Panagiotis Kokkalis ◽

Andreas Richter ◽

Mihalis Vrekoussis ◽

...

Keyword(s):

Optical Absorption ◽

Absorption Spectroscopy ◽

Optimal Estimation ◽

Differential Optical Absorption Spectroscopy ◽

Optical Absorption Spectroscopy ◽

Retrieval Algorithm ◽

Aerosol Extinction ◽

The Sun ◽

Tropospheric Aerosol ◽

Vertical Distributions

Abstract. In this study, we report on the retrieval of aerosol extinction profiles from ground-based scattered sunlight multi-axis differential optical absorption spectroscopy (MAX-DOAS) measurements, carried out at Athens, Greece. It is the first time that aerosol profiles are retrieved from MAX-DOAS measurements in Athens. The reported aerosol vertical distributions at 477 nm are derived from the oxygen dimer (O4) differential-slant-column-density observations at different elevation angles by applying the BRemen Optimal estimation REtrieval for Aerosol and trace gaseS (BOREAS) retrieval algorithm. Four case studies have been selected for validation purposes; the retrieved aerosol profiles and the corresponding aerosol optical depths (AODs) from the MAX-DOAS are compared with lidar extinction profiles and with sun-photometric measurements (Aerosol Robotic Network, AERONET, observations), respectively. Despite the different approach of each method regarding the retrieval of the aerosol information, the comparison with the lidar measurements at 532 nm reveals a very good agreement in terms of vertical distribution, with r>0.90 in all cases. The AODs from the MAX-DOAS and the sun photometer (the latter at 500 nm) show a satisfactory correlation (with 0.45 < r < 0.7 in three out of the four cases). The comparison indicates that the MAX-DOAS systematically underestimates the AOD in the cases of large particles (small Ångström exponent) and for measurements at small relative azimuthal angles between the viewing direction and the sun. Better agreement is achieved in the morning, at large relative azimuthal angles. Overall, the aerosol profiles retrieved from MAX-DOAS measurements are of good quality; thus, new perspectives are opened up for assessing urban aerosol pollution on a long-term basis in Athens from continuous and uninterrupted MAX-DOAS measurements.

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Recent applications of Differential Optical Absorption Spectroscopy: Halogen chemistry in the lower troposphere

Journal de Physique IV (Proceedings) ◽

10.1051/jp4:2004121015 ◽

2004 ◽

Vol 121 ◽

pp. 223-238 ◽

Cited By ~ 4

Author(s):

A. Saiz-Lopez ◽

J. M.C. Plane

Keyword(s):

Optical Absorption ◽

Absorption Spectroscopy ◽

Lower Troposphere ◽

Differential Optical Absorption Spectroscopy ◽

Optical Absorption Spectroscopy ◽

Halogen Chemistry

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

Remote Sensing ◽

10.3390/rs13112098 ◽

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.

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

Atmospheric Chemistry and Physics ◽

10.5194/acp-7-69-2007 ◽

2007 ◽

Vol 7 (1) ◽

pp. 69-79 ◽

Cited By ~ 20

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.

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