Retrieval of near-surface sulfur dioxide (SO<sub>2</sub>) concentrations at a global scale using IASI satellite observations
SO<sub>2</sub> from volcanic eruptions is now operationally monitored from space in both the ultraviolet (UV) and thermal infrared (TIR) spectral range, but anthropogenic SO<sub>2</sub> has almost solely been measured from UV sounders. Indeed, TIR instruments are well known t...
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2016-02-01
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| Series: | Atmospheric Measurement Techniques |
| Online Access: | http://www.atmos-meas-tech.net/9/721/2016/amt-9-721-2016.pdf |
| _version_ | 1819294093309640704 |
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| author | S. Bauduin L. Clarisse J. Hadji-Lazaro N. Theys C. Clerbaux P.-F. Coheur |
| author_facet | S. Bauduin L. Clarisse J. Hadji-Lazaro N. Theys C. Clerbaux P.-F. Coheur |
| author_sort | S. Bauduin |
| collection | DOAJ |
| description | SO<sub>2</sub> from volcanic eruptions is now operationally monitored from space in both the ultraviolet (UV) and thermal infrared (TIR) spectral range, but anthropogenic SO<sub>2</sub> has almost solely been measured from UV sounders. Indeed, TIR instruments are well known to have a poor sensitivity to the planetary boundary layer (PBL), due to generally low thermal contrast (TC) between the ground and the air above it. Recent studies have demonstrated the capability
of the Infrared Atmospheric Sounding Interferometer (IASI) to measure
near-surface SO<sub>2</sub> locally, for specific atmospheric conditions. In this
work, we develop a retrieval method allowing the inference of SO<sub>2</sub>
near-surface concentrations from IASI measurements at a global scale. This
method consists of two steps. Both are based on the computation of radiance
indexes representing the strength of the SO<sub>2</sub> <i>ν</i><sub>3</sub> band in IASI spectra. The first step allows the peak altitude of SO<sub>2</sub> to be retrieved and near-surface SO<sub>2</sub> to be selected. In the second step, 0–4 km columns of SO<sub>2</sub> are inferred using a look-up table (LUT) approach. Using this new retrieval method, we obtain the first global distribution of near-surface
SO<sub>2</sub> from IASI-A, and identify the dominant anthropogenic hotspot sources
and volcanic degassing. The 7-year daily time evolution of SO<sub>2</sub> columns
above two industrial source areas (Beijing in China and Sar Cheshmeh in Iran)
is investigated and correlated to the seasonal variations of the parameters
that drive the IASI sensitivity to the PBL composition. Apart from TC, we
show that humidity is the most important parameter which determines IR
sensitivity to near-surface SO<sub>2</sub> in the <i>ν</i><sub>3</sub> band. As IASI provides global measurements twice daily, the differences between the retrieved
columns for the morning and evening orbits are investigated. This paper
finally presents a first intercomparison of the measured 0–4 km columns
with an independent iterative retrieval method and with observations of the
Ozone Monitoring Instrument (OMI). |
| first_indexed | 2024-12-24T04:20:50Z |
| format | Article |
| id | doaj.art-5ee1e6577b72439f9a3f8fc07002b2cd |
| institution | Directory Open Access Journal |
| issn | 1867-1381 1867-8548 |
| language | English |
| last_indexed | 2024-12-24T04:20:50Z |
| publishDate | 2016-02-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Atmospheric Measurement Techniques |
| spelling | doaj.art-5ee1e6577b72439f9a3f8fc07002b2cd2022-12-21T17:15:48ZengCopernicus PublicationsAtmospheric Measurement Techniques1867-13811867-85482016-02-019272174010.5194/amt-9-721-2016Retrieval of near-surface sulfur dioxide (SO<sub>2</sub>) concentrations at a global scale using IASI satellite observationsS. Bauduin0L. Clarisse1J. Hadji-Lazaro2N. Theys3C. Clerbaux4P.-F. Coheur5Spectroscopie de l'atmosphère, Service de Chimie Quantique et Photophysique, Université Libre de Bruxelles (ULB), Brussels, BelgiumSpectroscopie de l'atmosphère, Service de Chimie Quantique et Photophysique, Université Libre de Bruxelles (ULB), Brussels, BelgiumSorbonne Universités, UPMC Univ. Paris 06, Université Versailles St-Quentin, CNRS/INSU, LATMOS-IPSL, Paris, FranceBelgian Institute for Space Aeronomy (BIRA-IASB), Brussels, BelgiumSpectroscopie de l'atmosphère, Service de Chimie Quantique et Photophysique, Université Libre de Bruxelles (ULB), Brussels, BelgiumSpectroscopie de l'atmosphère, Service de Chimie Quantique et Photophysique, Université Libre de Bruxelles (ULB), Brussels, BelgiumSO<sub>2</sub> from volcanic eruptions is now operationally monitored from space in both the ultraviolet (UV) and thermal infrared (TIR) spectral range, but anthropogenic SO<sub>2</sub> has almost solely been measured from UV sounders. Indeed, TIR instruments are well known to have a poor sensitivity to the planetary boundary layer (PBL), due to generally low thermal contrast (TC) between the ground and the air above it. Recent studies have demonstrated the capability of the Infrared Atmospheric Sounding Interferometer (IASI) to measure near-surface SO<sub>2</sub> locally, for specific atmospheric conditions. In this work, we develop a retrieval method allowing the inference of SO<sub>2</sub> near-surface concentrations from IASI measurements at a global scale. This method consists of two steps. Both are based on the computation of radiance indexes representing the strength of the SO<sub>2</sub> <i>ν</i><sub>3</sub> band in IASI spectra. The first step allows the peak altitude of SO<sub>2</sub> to be retrieved and near-surface SO<sub>2</sub> to be selected. In the second step, 0–4 km columns of SO<sub>2</sub> are inferred using a look-up table (LUT) approach. Using this new retrieval method, we obtain the first global distribution of near-surface SO<sub>2</sub> from IASI-A, and identify the dominant anthropogenic hotspot sources and volcanic degassing. The 7-year daily time evolution of SO<sub>2</sub> columns above two industrial source areas (Beijing in China and Sar Cheshmeh in Iran) is investigated and correlated to the seasonal variations of the parameters that drive the IASI sensitivity to the PBL composition. Apart from TC, we show that humidity is the most important parameter which determines IR sensitivity to near-surface SO<sub>2</sub> in the <i>ν</i><sub>3</sub> band. As IASI provides global measurements twice daily, the differences between the retrieved columns for the morning and evening orbits are investigated. This paper finally presents a first intercomparison of the measured 0–4 km columns with an independent iterative retrieval method and with observations of the Ozone Monitoring Instrument (OMI).http://www.atmos-meas-tech.net/9/721/2016/amt-9-721-2016.pdf |
| spellingShingle | S. Bauduin L. Clarisse J. Hadji-Lazaro N. Theys C. Clerbaux P.-F. Coheur Retrieval of near-surface sulfur dioxide (SO<sub>2</sub>) concentrations at a global scale using IASI satellite observations Atmospheric Measurement Techniques |
| title | Retrieval of near-surface sulfur dioxide (SO<sub>2</sub>) concentrations at a global scale using IASI satellite observations |
| title_full | Retrieval of near-surface sulfur dioxide (SO<sub>2</sub>) concentrations at a global scale using IASI satellite observations |
| title_fullStr | Retrieval of near-surface sulfur dioxide (SO<sub>2</sub>) concentrations at a global scale using IASI satellite observations |
| title_full_unstemmed | Retrieval of near-surface sulfur dioxide (SO<sub>2</sub>) concentrations at a global scale using IASI satellite observations |
| title_short | Retrieval of near-surface sulfur dioxide (SO<sub>2</sub>) concentrations at a global scale using IASI satellite observations |
| title_sort | retrieval of near surface sulfur dioxide so sub 2 sub concentrations at a global scale using iasi satellite observations |
| url | http://www.atmos-meas-tech.net/9/721/2016/amt-9-721-2016.pdf |
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