scholarly journals Accurate laser measurements of ozone absorption cross-sections in the Hartley band

2014 ◽  
Vol 7 (8) ◽  
pp. 8067-8100 ◽  
Author(s):  
J. Viallon ◽  
S. Lee ◽  
P. Moussay ◽  
K. Tworek ◽  
M. Petersen ◽  
...  
Keyword(s):  
Gas Phase ◽  
Cross Section ◽  
Cross Sections ◽  
Radiative Forcing ◽  
Nitrogen Monoxide ◽  
Air Pollutant ◽  
Tropospheric Chemistry ◽  
Absorption Cross ◽  
Ozone Absorption ◽  
Hartley Band

Abstract. Ozone plays a crucial role in tropospheric chemistry, is the third largest contributor to greenhouse radiative forcing after carbon dioxide and methane and also a toxic air pollutant affecting human health and agriculture. Long-term measurements of tropospheric ozone have been performed globally for more than 30 years with UV photometers, all relying on the absorption of ozone at the 253.65 nm line of mercury. We have re-determined this cross-section and report a value of 11.27 × 10−18 cm2 molecule−1 with an expanded relative uncertainty of 0.84 %. This is lower than the conventional value currently in use and measured by Hearn in 1961 with a relative difference of 1.8%, with the consequence that historically reported ozone concentrations should be increased by 1.8%. In order to perform the new measurements of cross sections with reduced uncertainties, a system to generate pure ozone in the gas phase together with an optical system based on a UV laser with lines in the Hartley band, including accurate path length measurement of the absorption cell and a careful evaluation of possible impurities in the ozone sample by mass spectrometry and Fourier Transform Infrared spectroscopy was setup. This resulted in new measurements of absolute values of ozone absorption cross sections of 9.48 × 10−18, 10.44 × 10−18, and 11.07 × 10−18 cm2 molecule−1, with relative expanded uncertainties better than 0.6%, for the wavelengths (in vacuum) of 244.062, 248.32, and 257.34 nm respectively. The cross-section at the 253.65 nm line of mercury was determined by comparisons using a Standard Reference Photometer equipped with a mercury lamp as the light source. The newly reported value should be used in the future to obtain the most accurate measurements of ozone concentration, which are in closer agreement with non UV photometry based methods such as the gas phase titration of ozone with nitrogen monoxide.

scholarly journals Accurate measurements of ozone absorption cross-sections in the Hartley band

2015 ◽  
Vol 8 (3) ◽  
pp. 1245-1257 ◽  
Author(s):  
J. Viallon ◽  
S. Lee ◽  
P. Moussay ◽  
K. Tworek ◽  
M. Petersen ◽  
...  
Keyword(s):  
Gas Phase ◽  
Cross Section ◽  
Cross Sections ◽  
Radiative Forcing ◽  
Nitrogen Monoxide ◽  
Air Pollutant ◽  
Tropospheric Chemistry ◽  
Absorption Cross ◽  
Ozone Absorption ◽  
Hartley Band

Abstract. Ozone plays a crucial role in tropospheric chemistry, is the third largest contributor to greenhouse radiative forcing after carbon dioxide and methane and also a toxic air pollutant affecting human health and agriculture. Long-term measurements of tropospheric ozone have been performed globally for more than 30 years with UV photometers, all relying on the absorption of ozone at the 253.65 nm line of mercury. We have re-determined this cross-section and report a value of 11.27 x 10−18 cm2 molecule−1 with an expanded relative uncertainty of 0.86% (coverage factor k= 2). This is lower than the conventional value currently in use and measured by Hearn (1961) with a relative difference of 1.8%, with the consequence that historically reported ozone concentrations should be increased by 1.8%. In order to perform the new measurements of cross-sections with reduced uncertainties, a system was set up to generate pure ozone in the gas phase together with an optical system based on a UV laser with lines in the Hartley band, including accurate path length measurement of the absorption cell and a careful evaluation of possible impurities in the ozone sample by mass spectrometry and Fourier transform infrared spectroscopy. This resulted in new measurements of absolute values of ozone absorption cross-sections of 9.48 x 10−18, 10.44 x 10−18 and 11.07 x 10−18 cm2 molecule−1, with relative expanded uncertainties better than 0.7%, for the wavelengths (in vacuum) of 244.06, 248.32, and 257.34 nm respectively. The cross-section at the 253.65 nm line of mercury was determined by comparisons using a Standard Reference Photometer equipped with a mercury lamp as the light source. The newly reported value should be used in the future to obtain the most accurate measurements of ozone concentration, which are in closer agreement with non-UV-photometry based methods such as the gas phase titration of ozone with nitrogen monoxide.

scholarly journals Revised temperature dependent ozone absorption cross section spectra (Bogumil et al.) measured with the sciamachy satellite spectrometer

2013 ◽  
Vol 6 (2) ◽  
pp. 2449-2481 ◽  
Author(s):  
W. Chehade ◽  
V. Gorshelev ◽  
A. Serdyuchenko ◽  
J. P. Burrows ◽  
M. Weber
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Absorption Cross Section ◽  
Total Ozone ◽  
Published Data ◽  
Absorption Cross ◽  
Atmospheric Conditions ◽  
Cross Section Data ◽  
Ozone Absorption ◽  
Section Data

Abstract. Ozone absorption cross section spectra and other trace gases had been measured using the Scanning Imaging Absorption spectroMeter for Atmospheric ChartograpHY (SCIAMACHY) satellite instrument at relevant atmospheric conditions. The measured cross sections were relative cross sections and were converted to absolute values using published data. Using the SCIAMACHY's FM cross sections as published by Bogumil et al. (2003) in the SCIAMACHY retrievals of total ozone leads to an overestimation in the total ozone by 5% compared to collocated GOME data. This work presents the procedures followed to correct the ozone cross section data as published in Bogumil et al. (2003) starting from original raw data (optical density spectra) from the original measurements. The revised data agrees well within 3% with other published ozone cross-sections and preserves the correct temperature dependence in the Hartley, Huggins, Chappuis and Wolf bands. SCIAMACHY's total ozone columns retrieved using the revised cross section data are shown to be within 1% compared to the ozone amounts retrieved routinely from SCIAMACHY.

scholarly journals Radiative properties of coated black carbon aggregates: numerical simulations and radiative forcing estimates

2021 ◽  
Author(s):  
Baseerat Romshoo ◽  
Thomas Müller ◽  
Sascha Pfeifer ◽  
Jorge Saturno ◽  
Andreas Nowak ◽  
...  
Keyword(s):  
Black Carbon ◽  
Cross Section ◽  
Cross Sections ◽  
Asymmetry Parameter ◽  
Radiative Forcing ◽  
Single Scattering ◽  
Radiative Properties ◽  
Absorption Cross ◽  
Parametrization Scheme ◽  
The Cross

Abstract. The formation of black carbon fractal aggregates (BCFAs) from combustion and subsequent aging involves several stages resulting in modifications of particle size, morphology, and composition over time. To understand and quantify how each of these modifications influences the BC radiative forcing, the radiative properties of BCFAs are modelled. Owing to the high computational time involved in numerical modelling, there are some gaps in terms of data coverage and knowledge regarding how radiative properties of coated BCFAs vary over the range of different factors (size, shape, and composition). This investigation bridged those gaps by following a state-of-the-art description scheme of BCFAs based on morphology, composition, and wavelength. The BCFAs radiative properties were investigated as a function of the radius of the primary particle (ao), fractal dimension (Df), fraction of organics (forganics), wavelength (λ), and mobility diameter (Dmob). The radiative properties are calculated using the multiple sphere T-matrix (MSTM) method. Amongst size, morphology, and composition, all the radiative properties showed the highest variability with changing size. The cross-sections varied from 0.0001 μm2 to 0.1 μm2 for BCFA Dmob ranging from 24 nm to 810 nm. After size or Dmob, the absorption cross-section (Cabs) and BC mass absorption cross-section (MACBC) showed the highest sensitivity towards composition or forganics, whereas the asymmetry parameter (g) showed higher dependence on morphology, which is represented by Df. The Ångstrom absorption exponent varied from 1.06 up to 3.6 and increases with the fraction of organics (forganics). The values of the absorption enhancement factor (Eλ) were found between 1.01 and 3.28 in the visible spectrum. The Eλ was derived from Mie calculations for coated volume equivalent spheres, and from MSTM for coated BCFAs. Mie calculated enhancement factors were found to be larger by a factor of 1.1 to 1.5 than their corresponding values calculated from the MSTM method. It is shown that radiative forcings are highly sensitive towards modifications in morphology and composition. The black carbon radiative forcing ΔFTOA (Wm−2) decreases up to 61 % as the BCFA becomes more compact in morphology. Whereas, there is a decrease of > 50 % in ΔFTOA as the organic content of the particle increase up to 90 %. Based on our results, which showed a significant effect of coating and morphology on the BC radiative properties, a parametrization scheme for radiative properties of BC fractal aggregates was developed, which is applicable for modelling, ambient, and laboratory-based BC studies. The parameterization scheme for the cross-sections (extinction, absorption, and scattering), single scattering albedo (SSA), and asymmetry parameter (g) of pure and coated BCFAs as a function of Dmob were derived from tabulated results of the MSTM method. Spanning over an extensive parameter space, the developed parametrization scheme showed promisingly high accuracy up to 98 % for the cross-sections, 97 % for single scattering albedos (SSA), and 82 % for asymmetry parameter (g).

scholarly journals High spectral resolution ozone absorption cross-sections – Part 1: Measurements, data analysis and comparison with previous measurements around 293 K

2014 ◽  
Vol 7 (2) ◽  
pp. 609-624 ◽  
Author(s):  
V. Gorshelev ◽  
A. Serdyuchenko ◽  
M. Weber ◽  
W. Chehade ◽  
J. P. Burrows
Keyword(s):  
Data Analysis ◽  
Cross Section ◽  
Cross Sections ◽  
Spectral Resolution ◽  
Spectral Region ◽  
Uncertainty Budget ◽  
High Spectral Resolution ◽  
Absorption Cross ◽  
Ozone Absorption ◽  
Better Than

Abstract. In this paper we discuss the methodology of taking broadband relative and absolute measurements of ozone cross-sections including uncertainty budget, experimental set-ups, and methods for data analysis. We report on new ozone absorption cross-section measurements in the solar spectral region using a combination of Fourier transform and echelle spectrometers. The new cross-sections cover the spectral range 213–1100 nm at a spectral resolution of 0.02–0.06 nm in the UV–visible and 0.12–0.24 nm in the IR at eleven temperatures from 193 to 293 K in steps of 10 K. The absolute accuracy is better than three percent for most parts of the spectral region and wavelength calibration accuracy is better than 0.005 nm. The new room temperature cross-section data are compared in detail with previously available literature data. The temperature dependence of our cross-sections is described in a companion paper (Serdyuchenko et al., 2014).

scholarly journals Revised temperature-dependent ozone absorption cross-section spectra (Bogumil et al.) measured with the SCIAMACHY satellite spectrometer

2013 ◽  
Vol 6 (11) ◽  
pp. 3055-3065 ◽  
Author(s):  
W. Chehade ◽  
V. Gorshelev ◽  
A. Serdyuchenko ◽  
J. P. Burrows ◽  
M. Weber
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Absorption Cross Section ◽  
Total Ozone ◽  
Published Data ◽  
Absorption Cross ◽  
Cross Section Data ◽  
Temperature Dependent ◽  
Ozone Absorption ◽  
Section Data

Abstract. Absorption cross-section spectra for ozone and other trace gases had been measured using the Scanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) satellite instrument at relevant atmospheric conditions. The measured cross sections were relative cross sections and were converted to absolute values using published data. Using SCIAMACHY's FM cross sections as published by Bogumil et al. (2003) in the SCIAMACHY retrievals of total ozone leads to an overestimation in the total ozone by 5% compared to collocated GOME data. This work presents the procedures followed to correct the ozone cross-section data starting from original raw data (optical density spectra). The quality of the revised temperature-dependent ozone absorption cross sections is investigated over SCIAMACHY's entire spectral range. The revised data agree well within 3% with other published ozone cross sections and preserve the correct temperature dependence in the Hartley, Huggins, Chappuis and Wulf bands as displayed by the literature data. SCIAMACHY's total ozone columns retrieved using the revised cross-section data are shown to be within 1% compared to the ozone amounts retrieved routinely from SCIAMACHY, which uses Bogumil et al. (2003) data but adjusted with a scaling factor of 5.3% and a wavelength shift of 0.08 nm.

scholarly journals Impact of using a new ultraviolet ozone absorption cross-section dataset on OMI ozone profile retrievals

2020 ◽  
Vol 13 (11) ◽  
pp. 5845-5854
Author(s):  
Juseon Bak ◽  
Xiong Liu ◽  
Manfred Birk ◽  
Georg Wagner ◽  
Iouli E. Gordon ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Absorption Cross Section ◽  
High Latitudes ◽  
Absorption Cross ◽  
Cross Section Data ◽  
Ozone Absorption ◽  
Section Data ◽  
Ozone Profile ◽  
The Impact

Abstract. We evaluate different sets of high-resolution ozone absorption cross-section data for use in atmospheric ozone profile measurements in the Hartley and Huggins bands with a particular focus on BDM 1995 (Daumont et al. 1992; Brion et al., 1993; Malicet et al., 1995), currently used in our retrievals, and a new laboratory dataset by Birk and Wagner (2018) (BW). The BDM cross-section data have been recommended to use for retrieval of ozone profiles using spaceborne nadir-viewing backscattered ultraviolet (BUV) measurements since its improved performance was demonstrated against other cross-sections including Bass and Paur (1985) (BP) and those of Serdyuchenko et al. (2014) and Gorshelev et al. (2014) (SER) by the “Absorption Cross-Sections of Ozone” (ACSO) activity. The BW laboratory data were recently measured within the framework of the European Space Agency (ESA) project SEOM-IAS (Scientific Exploitation of Operational Missions – Improved Atmospheric Spectroscopy Databases) to provide an advanced absorption cross-section database. The BW cross-sections are made from measurements at more temperatures and in a wider temperature range than BDM, especially for low temperatures. Relative differences of cross-sections between BW and BDM range from ∼2 % at shorter UV wavelengths to ∼5 % at longer UV wavelengths at warm temperatures. Furthermore, these differences dynamically increase by up to ±40 % at cold temperatures due to no BDM measurements having been made below 218 K. We evaluate the impact of using different cross-sections on ozone profile retrievals from Ozone Monitoring Instrument (OMI) measurements. Correspondingly, this impact leads to significant differences in individual ozone retrievals by up to 50 % in the tropopause where the coldest atmospheric temperatures are observed. Bottom atmospheric layers illustrate the significant change of the retrieved ozone values, with differences of 20 % in low latitudes, which is not the case in high latitudes because the ozone retrievals are mainly controlled by a priori ozone information in high latitudes due to less photon penetration down to the lower troposphere. Validation with ozonesonde observations demonstrates that BW and BDM retrievals show altitude-dependent bias oscillations of similar magnitude relative to ozonesonde measurements, much smaller than those of both BP and SER retrievals. However, compared to BDM, BW retrievals show significant reduction in standard deviation, by up to 15 %, especially at the coldest atmospheric temperatures. Such improvement is achieved mainly by the better characterization of the temperature dependence of ozone absorption.

scholarly journals Impact of using a new ultraviolet ozone absorption cross-section dataset on OMI ozone profile retrievals

2020 ◽  
Author(s):  
Juseon Bak ◽  
Xiong Liu ◽  
Manfred Birk ◽  
Georg Wagner ◽  
Iouli E. Gordon ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Absorption Cross Section ◽  
Atmospheric Temperature ◽  
High Latitudes ◽  
Absorption Cross ◽  
Cross Section Data ◽  
Ozone Absorption ◽  
Section Data ◽  
Ozone Profile

Abstract. We evaluate different sets of high-resolution ozone absorption cross-section data for use in atmospheric ozone profile measurements in the Hartley and Huggins bands with a particular focus on Brion-Daumont-Malicet et al. (1995) (BDM) currently used in our retrievals, and a new laboratory dataset by Birk and Wagner (BW) (2018). The BDM cross-section data have been recommended to use for retrieval of ozone profiles using spaceborne nadir viewing Backscattered UltraViolet (BUV) measurements since its improved performance was demonstrated against other cross-sections including Bass and Paur (1985) (BP) and those of Serdyuchenko et al (2014) and Gorshelev et al. (2014) (SER) by the Absorption Cross-Sections of Ozone (ACSO) activity. The BW laboratory data were recently measured within the framework of the ESA project SEOM-IAS (Scientific Exploitation of Operational Missions – Improved Atmospheric Spectroscopy Databases) to provide an advanced absorption cross-section database. The BW cross-sections are made from measurements at more temperatures and in a wider temperature range than BDM, especially for low temperatures. Compared to BW, BDM cross-sections are positively biased from ~2 % at shorter UV to ~5 % at longer UV at warm temperatures. Furthermore, these biases dynamically increase by up to ± 40 % at cold temperatures due to no BDM measurements below 218 K. We evaluate the impact of using different cross-sections on ozone profile retrievals from Ozone Monitoring Instrument (OMI) measurements. Correspondingly, this impact leads to significant differences in individual ozone retrievals by up to 50 % in the tropopause where the coldest atmospheric temperature is observed. Bottom atmospheric layers illustrate the significant change of the retrieved ozone values with biases of 20 % in low latitudes, which is not the case in high latitudes because the ozone retrievals are mainly controlled by a priori ozone information in high latitudes due to less photon penetration down to the lower troposphere. Validation with ozonesonde observations demonstrates that BW and BDM retrievals show altitude-dependent bias oscillations of similar magnitude relative to ozonesonde measurements, much smaller than those of both BP and SER retrievals. However, compared to BDM, BW retrievals show significant reduction in standard deviation by up to 15 %, especially at the coldest atmospheric temperature. Such improvement is achieved mainly by th better characterization of the temperature dependence of ozone absorption.

scholarly journals Spectrally Resolved Ultraviolet (UV) Absorption Cross-Sections of Alkali Hydroxides and Chlorides Measured in Hot Flue Gases

2018 ◽  
Vol 72 (9) ◽  
pp. 1388-1395 ◽  
Author(s):  
Wubin Weng ◽  
Tomas Leffler ◽  
Christian Brackmann ◽  
Marcus Aldén ◽  
Zhongshan Li
Keyword(s):  
Gas Phase ◽  
Cross Section ◽  
Cross Sections ◽  
Absorption Cross Section ◽  
Relative Concentration ◽  
Uv Absorption ◽  
Flue Gases ◽  
Absorption Cross ◽  
Spectrally Resolved ◽  
Alkali Chlorides

Spectrally resolved ultraviolet (UV) absorption cross-sections of gas-phase sodium chloride (NaCl), potassium hydroxide (KOH), and sodium hydroxide (NaOH) were measured, for the first time, in hot flue gases at different temperatures. Homogenous gas-phase NaCl, KCl (potassium chloride), NaOH, and KOH at temperatures 1200 K, 1400 K, 1600 K, and 1850 K were prepared in the post-flame zone of laminar flames by seeding nebulized droplets out of aqueous solution of corresponding alkali species. The amount of droplets seeded into the flame was kept constant, so the relative concentration of different alkali species can be derived. The broadband UV absorption cross-section of KCl vapor reported by Leffler et al. was adopted to derive the absorption cross-section curves of NaCl, NaOH, and KOH with the corresponding measured spectrally resolved absorbance spectra. No significant changes in the spectral structures in the absorption cross-sections were found as the temperature varied between 1200 K and 1850 K, except for NaOH at around 320 nm. The difference between the absorption spectral curves of alkali chlorides and hydroxides is significant at wavelengths above 300 nm, which thus can be used to distinguish and obtain the concentrations of alkali chlorides and hydroxides in the broadband UV absorption measurements.

scholarly journals Ultraviolet Absorption Cross-Sections of Ammonia at Elevated Temperatures for Nonintrusive Quantitative Detection in Combustion Environments

2021 ◽  
pp. 000370282199044
Author(s):  
Wubin Weng ◽  
Shen Li ◽  
Marcus Aldén ◽  
Zhongshan Li
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Absorption Cross Section ◽  
Elevated Temperatures ◽  
Uv Absorption ◽  
Energy Utilization ◽  
Quantitative Detection ◽  
Absorption Cross ◽  
Hot Gas

Ammonia (NH3) is regarded as an important nitrogen oxides (NOx) precursor and also as an effective reductant for NOx removal in energy utilization through combustion, and it has recently become an attractive non-carbon alternative fuel. To have a better understanding of thermochemical properties of NH3, accurate in situ detection of NH3 in high temperature environments is desirable. Ultraviolet (UV) absorption spectroscopy is a feasible technique. To achieve quantitative measurements, spectrally resolved UV absorption cross-sections of NH3 in hot gas environments at different temperatures from 295 K to 590 K were experimentally measured for the first time. Based on the experimental results, vibrational constants of NH3 were determined and used for the calculation of the absorption cross-section of NH3 at high temperatures above 590 K using the PGOPHER software. The investigated UV spectra covered the range of wavelengths from 190 nm to 230 nm, where spectral structures of the [Formula: see text] transition of NH3 in the umbrella bending mode, v2, were recognized. The absorption cross-section was found to decrease at higher temperatures. For example, the absorption cross-section peak of the (6, 0) vibrational band of NH3 decreases from ∼2 × 10−17 to ∼0.5 × 10−17 cm2/molecule with the increase of temperature from 295 K to 1570 K. Using the obtained absorption cross-section, in situ nonintrusive quantification of NH3 in different hot gas environments was achieved with a detection limit varying from below 10 parts per million (ppm) to around 200 ppm as temperature increased from 295 K to 1570 K. The quantitative measurement was applied to an experimental investigation of NH3 combustion process. The concentrations of NH3 and nitric oxide (NO) in the post flame zone of NH3–methane (CH4)–air premixed flames at different equivalence ratios were measured.

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