Isabelle De Smedt

Isabelle De Smedt
Belgian Institute for Space Aeronomy | BIRA-IASB · Division of Atmospheric Composition

Dr.

About

208
Publications
32,282
Reads
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6,814
Citations
Citations since 2017
63 Research Items
4131 Citations
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Introduction
- Belgian Institute for Space Aeronomy (BIRA-IASB), Federal Space Pole, Brussels, Belgium. - Atmospheric Composition Division. - UV-Vis DOAS group research (group leader: Dr. Michel Van Roozendael) http://uv-vis.aeronomy.be The DOAS group concentrates on atmospheric chemistry related research. Retrieval algorithms applied to ground-based and satellite instruments are developed to monitor the atmospheric concentration of trace gases important for air quality and climate change studies.
Additional affiliations
September 2020 - September 2021
ICOVAC (https://eo4society.esa.int/projects/icovac)
Position
  • https://eo4society.esa.int/projects/icovac/
Description
  • The ICOVAC project is an ESA response to the COVID crisis and includes both observational and modelling activity components in order to assess the impacts of the various lockdown measures on air quality and climate.
January 2019 - present
S5P L3 for Terrascope (https://viewer.terrascope.be)
Position
  • Open-source satellite images
Description
  • European satellites are constantly collecting data about the Earth. Terrascope makes this data easily accessible and provides access to the open-source satellite data of the EC’s Copernicus programme
September 2016 - May 2021
S5 L2 Processor Component Development (https://sentinel.esa.int/web/sentinel/missions/sentinel-5)
Position
  • Sentinel-5 Level-2 Prototype Processor Development
Description
  • Definition of an algorithm baseline for each of the S5 operational L2 products, estimate of their performance with an independent scientific algorithm verification, and implementation of this algorithm baseline in a prototype processor software. ESA will deliver the algorithms to EUMETSAT that will become part of the EPS-SG ground segment.
Education
September 2005 - June 2011
Université Libre de Bruxelles
Field of study
  • Engineering Sciences
September 2001 - September 2002
University of Glasgow
Field of study
  • Electronic and Electrical Engineering Sciences, Faculty of Engineering
September 1996 - June 2001
Université Libre de Bruxelles
Field of study
  • Engineering Sciences (Physics), Ecole polytechnique

Publications

Publications (208)
Article
Full-text available
China was the first country to undergo large-scale lockdowns in response to the pandemic in early 2020 and a progressive return to normalization after April 2020. Spaceborne observations of atmospheric nitrogen dioxide (NO2) and oxygenated volatile organic compounds (OVOCs), including formaldehyde (HCHO), glyoxal (CHOCHO), and peroxyacetyl nitrate...
Preprint
Full-text available
The aim of this paper is two-fold: to provide guidance on how to best interpret TROPOMI trace gas retrievals and to highlight how TROPOMI trace gas data can be used to understand event-based impacts on air quality from regional to city-scales around the globe. For this study, we present the observed changes in the atmospheric column amounts of five...
Preprint
Full-text available
We present the first global glyoxal (CHOCHO) tropospheric column product derived from the TROPOspheric Monitoring Instrument (TROPOMI) on board of the Sentinel-5 Precursor satellite. Atmospheric glyoxal results from the oxidation of other non-methane volatile organic compounds (NMVOCs) and from direct emissions caused by combustion processes. There...
Preprint
Full-text available
Sensitive and accurate detection of sulfur dioxide (SO2) from space is important for monitoring and estimating global sulfur emissions. Inspired by detection methods applied in the thermal infrared, we present here a new scheme to retrieve SO2 columns from satellite observations of ultraviolet back-scattered radiances. The retrieval is based on a m...
Article
Full-text available
Atmospheric acidity is increasingly determined by carbon dioxide and organic acids 1–3 . Among the latter, formic acid facilitates the nucleation of cloud droplets ⁴ and contributes to the acidity of clouds and rainwater 1,5 . At present, chemistry–climate models greatly underestimate the atmospheric burden of formic acid, because key processes rel...
Preprint
Full-text available
The TROPOspheric Monitoring Instrument (TROPOMI), launched in October 2017 on board the Sentinel-5 Precursor (S5P) satellite, monitors the composition of the Earth's atmosphere at an unprecedented horizontal resolution as fine as 3.5 × 5.5 km2. This paper assess the performances of the TROPOMI formaldehyde (HCHO) operational product compared to its...
Article
Full-text available
Satellite HCHO data are widely used as a reliable proxy of non-methane volatile organic compounds (NMVOCs) to constrain underlying emissions and chemistry. Here, we examine global significant changes in HCHO columns at the early stage of the COVID-19 pandemic (January-April 2020) compared with the same period in 2019 with observations from the TROP...
Conference Paper
Policies to regulate severe surface ozone pollution in cities in India are challenging to develop, due to the complex dependence on precursor emissions of volatile organic compounds (VOCs) and nitrogen oxides (NOx), non-linear chemistry leading to ozone formation, and very limited spatial and temporal surface air quality monitoring. Ratios of space...
Poster
https://agu2020fallmeeting-agu.ipostersessions.com/Default.aspx?s=65-D7-14-EE-EA-6E-C7-DE-D5-7A-A5-AC-3F-9F-42-8E
Article
Full-text available
Nitrous acid (HONO) is a precursor of the hydroxyl radical in the atmosphere, which controls the degradation of greenhouse gases, contributes to photochemical smog and ozone production, and influences air quality. Although biomass burning is known to contribute substantially to global aerosols and reactive gas emissions, pyrogenic contributions to...
Article
Full-text available
Surface ozone data from the Chinese Ministry of Ecology and Environment (MEE) network show sustained increases across the country over the 2013-2019 period. Despite Phase 2 of the Clean Air Action Plan targeting ozone pollution, ozone was higher in 2018-2019 than in previous years. The mean summer 2013-2019 trend in maximum 8 h average (MDA8) ozone...
Article
Full-text available
We present two-dimensional scanning Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) observations of nitrogen dioxide (NO2) and formaldehyde (HCHO) in Munich. Vertical columns and vertical distribution profiles of aerosol extinction coefficient, NO2 and HCHO are retrieved from the 2D MAX-DOAS observations. The measured surface aer...
Article
Full-text available
The QA4ECV (Quality Assurance for Essential Climate Variables) version 1.1 stratospheric and tropospheric NO2 vertical column density (VCD) climate data records (CDRs) from the OMI (Ozone Monitoring Instrument) satellite sensor are validated using NDACC (Network for the Detection of Atmospheric Composition Change) zenith-scattered light differentia...
Article
Full-text available
TROPOMI (the TROPOspheric Monitoring Instrument), on board the Sentinel-5 Precursor (S5P) satellite, has been monitoring the Earth's atmosphere since October 2017 with an unprecedented horizontal resolution (initially 7 km2×3.5 km2, upgraded to 5.5 km2×3.5 km2 in August 2019). Monitoring air quality is one of the main objectives of TROPOMI; it obta...
Article
Full-text available
Urban ozone (O3) formation can be limited by NO x , VOCs, or both, complicating the design of effective O3 abatement plans. A satellite-retrieved ratio of formaldehyde to NO2 (HCHO/NO2), developed from theory and modeling, has previously been used to indicate O3 formation chemistry. Here, we connect this space-based indicator to spatiotemporal vari...
Preprint
Full-text available
Abstract. TROPOMI (the TROPOspheric Monitoring Instrument), on-board the Sentinel-5 Precursor satellite, has been monitoring the Earth's atmosphere since October 2017, with an unprecedented horizontal resolution (initially 7×3.5 km<sup>2</sup>, upgraded to 5.5×3.5 km<sup>2</sup> since August 2019). Monitoring air quality is one of the main objectiv...
Preprint
Full-text available
Abstract. The QA4ECV version 1.1 stratospheric and tropospheric NO<sub>2</sub> vertical column density (VCD) climate data records (CDR) from the satellite sensor OMI are validated, using NDACC zenith scattered light DOAS (ZSL-DOAS) and Multi Axis-DOAS (MAX-DOAS) data as a reference. The QA4ECV OMI stratospheric VCD have a small bias of ~ 0.2 Pmolec...
Conference Paper
This contribution focuses on the operational GOME-2 trace gas column products developed in the framework of EUMETSAT's Satellite Application Facility on Atmospheric Composition Monitoring (AC-SAF). We present an overview of the retrieval algorithms for ozone, the minor trace gases NO2, SO2 and formaldehyde, as well as water vapour. We show examples...
Article
Full-text available
We describe a formaldehyde (HCHO) retrieval algorithm for the Geostationary Environment Monitoring Spectrometer (GEMS) that will be launched by the Korean Ministry of Environment in 2019. The algorithm comprises three steps: preprocesses, radiance fitting, and postprocesses. The preprocesses include a wavelength calibration, as well as interpolatio...
Article
Full-text available
A multi-axis differential optical absorption spectroscopy (MAX-DOAS) instrument was deployed in May and June 2016 at a monitoring station (37.18∘ N, 114.36∘ E) in the suburban area of Xingtai, which is one of the most polluted cities in the North China Plain (NCP), during the Atmosphere-Aerosol-Boundary Layer-Cloud (A²BC) experiment and Air chemist...
Article
Full-text available
We use 2005–2016 observations of formaldehyde (HCHO) columns over China from the OMI, GOME-2, and SCIAMACHY satellite instruments to evaluate long-term trends in emission inventories of volatile organic compounds (VOCs) that affect air quality. The observations show large increases over 2005–2016 in the North China Plain (+1.1 ± 0.5% a ⁻¹ relative...
Article
In order to study the years of the outbreak of the financial crisis in Greece, we use a continuous eight-year record (2008–2015) of formaldehyde, HCHO, columns retrieved from the GOME-2/MetOp-A and GOME-2/MetOp-B satellite instruments over two urban Greek regions, Thessaloniki and Athens. A statistical linear regression analysis that was applied to...
Article
Full-text available
Over the last four decades, space-based nadir observations of sulfur dioxide (SO2) proved to be a key data source for assessing the environmental impacts of volcanic emissions, for monitoring volcanic activity and early signs of eruptions, and ultimately mitigating related hazards on local populations and aviation. Despite its importance, a detaile...
Article
Full-text available
An improved algorithm for the retrieval of total and tropospheric nitrogen dioxide (NO2) columns from the Global Ozone Monitoring Experiment-2 (GOME-2) is presented. The refined retrieval will be implemented in a future version of the GOME Data Processor (GDP) as used by the EUMETSAT Satellite Application Facility on Atmospheric Composition and UV...
Article
Full-text available
We describe a formaldehyde (HCHO) retrieval algorithm for the Geostationary Environment Monitoring Spectrometer (GEMS) that will be launched by the Korean Ministry of Environment in 2019. The algorithm comprises three steps: pre-processes, radiance fitting, and post-processes. The pre-processes include a wavelength calibration, and interpolation an...
Conference Paper
This presentation focuses on tropospheric NO2 and ozone products from TROPOMI/Sentinel-5P as developed at the Remote Sensing Technology institute of the German Aerospace Center (DLR). We present an overview of the retrieval algorithms and show examples of air quality applications. The retrieval of tropospheric NO2 columns from TROPOMI uses an Diffe...
Article
Full-text available
Global observations of tropospheric nitrogen dioxide (NO2) columns have been shown to be feasible from space, but consistent multi-sensor records do not yet exist, nor are they covered by planned activities at the international level. Harmonised, multi-decadal records of NO2 columns and their associated uncertainties can provide crucial information...
Presentation
Full-text available
Operational monitoring of atmospheric gaseous and particular species of both tropospheric as well as stratospheric provenance sensed by satellite instruments are performed routinely in the Laboratory of Atmospheric Physics, Thessaloniki, Greece, using a suite of different ground based instruments. These include both a single and double Brewer spect...
Conference Paper
The Sentinel-5 Precursor (S5P) mission, launched in October 2017, started the operational atmospheric composition measurements from space as part of the European Copernicus programme. The payload of the S5P mission is the TROPOspheric Monitoring Instrument (TROPOMI) that provides key information on air quality, climate and the ozone layer with high...
Article
Full-text available
A Multi Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) instrument was deployed in May and June 2016 at a monitoring station (37.18°N, 114.36°E) in the suburban area of Xingtai (one of the most polluted cities in China) during the Atmosphere-Aerosol-Boundary Layer-Cloud (A²BC) and Air chemistry Research In Asia (ARIAs) joint experiment...
Article
Full-text available
We used the GEOS-Chem model and its adjoint to quantify Chinese non-methane volatile organic compound (NMVOC) emissions for the year 2007, using the tropospheric column concentrations of formaldehyde and glyoxal observed by the Global Ozone Monitoring Experiment 2A (GOME-2A) instrument and the Ozone Monitoring Instrument (OMI) as quantitative const...
Article
Full-text available
Global observations of tropospheric nitrogen dioxide (NO2) columns have been shown to be feasible from space, but consistent multi-sensor records do not yet exist, nor are they covered by planned activities on the international level. Harmonised, multi-decadal records of NO2 columns and their associated uncertainties can provide crucial information...
Article
Full-text available
Data from Earth observation (EO) satellites are increasingly used to monitor the environment, understand variability and change, inform evaluations of climate model forecasts, and manage natural resources. Policymakers are progressively relying on the information derived from these datasets to make decisions on mitigating and adapting to climate ch...
Article
Full-text available
An improved algorithm for the retrieval of total and tropospheric nitrogen dioxide (NO2) columns from the Global Ozone Monitoring Experiment-2 (GOME-2) is presented. The refined retrieval will be implemented in a future version of the GOME Data Processor (GDP) as used by the EUMETSAT Satellite Application Facility on Atmospheric Composition and UV...
Article
A major feedback between climate and atmospheric chemistry lies in the meteorological dependence of the emissions of biogenic volatile organic compounds (BVOCs), precursors of important climate forcers, aerosols, and ozone. Whereas the short-term response of BVOC emissions to meteorological drivers is fairly well simulated by current emission model...
Article
Full-text available
Nitrogen dioxide (NO2) and formaldehyde (HCHO) column data from satellite instruments are used for air quality and climate studies. Both NO2 and HCHO have been identified as precursors to the ozone (O3) and aerosol essential climate variables, and it is essential to quantify and characterise their uncertainties. Here we present an intercomparison o...
Article
To study air pollution and chemical transformation in North China, annual and seasonal variations of the concentrations of atmospheric constituents were analyzed for four representative sites in three different types of regions (two agricultural, Beijing and surroundings, atmospheric background) in North China during 2005–2015. Satellite-derived ve...
Preprint
Full-text available
Data from Earth Observation (EO) satellites are increasingly used to monitor the environment, understand variability and change, inform evaluations of climate model forecasts and manage natural resources. Policy makers are progressively relying on the information derived from these datasets to make decisions on mitigating and adapting to climate ch...
Article
Full-text available
NO2 is an important trace gas in both the stratosphere and troposphere. Since January 2007, the nadir-looking GOME-2 satellite instrument has been providing NO2 data on a global scale which is of great interest for climate research and atmospheric chemistry studies. In this contribution, we report on an improved algorithm for the retrieval of total...
Article
Full-text available
On board the Copernicus Sentinel-5 Precursor (S5P) platform, the TROPOspheric Monitoring Instrument (TROPOMI) is a double-channel, nadir-viewing grating spectrometer measuring solar back-scattered earthshine radiances in the ultraviolet, visible, near-infrared, and shortwave infrared with global daily coverage. In the ultraviolet range, its spectra...
Article
Full-text available
We used the GEOS-Chem model and its adjoint to quantify Chinese non-methane volatile organic compound (NMVOC) emissions for the year 2007, using the vertical column concentrations of formaldehyde and glyoxal observed by the Global Ozone Monitoring Experiment-2A (GOME-2A) instrument and the Ozone Monitoring Instrument (OMI) as constraints. We conduc...
Article
Full-text available
Nitrogen dioxide (NO2) and formaldehyde (HCHO) column data from satellite instruments are used for air quality and climate studies. Both NO2 and HCHO have been identified as precursors to the ozone and aerosol Essential Climate Variables, and it is essential to quantify and characterize their uncertainties. Here we present an intercomparison of NO2...
Conference Paper
The Sentinel-5 Precursor (S5P) platform was launched from Northern Russia on October 13, 2017 carrying the TROPOspheric Monitoring Instrument (TROPOMI). With a spatial resolution of 7x3.5 km², TROPOMI provides improved information on natural and anthropogenic emissions of trace gases and aerosols, with an unprecedented level of details. BIRA-IASB a...
Article
Full-text available
On board of the Copernicus Sentinel-5 Precursor (S5P) platform, the TROPOspheric Monitoring Instrument (TROPOMI) is a double channel nadir-viewing grating spectrometer measuring solar back-scattered earthshine radiances in the ultraviolet, visible, near-infrared and shortwave infrared with global daily coverage. In the ultraviolet range, its spectr...
Article
Full-text available
Determining effective strategies for mitigating surface ozone (O3) pollution requires knowledge of the relative ambient concentrations of its precursors, NO x , and VOCs. The space-based tropospheric column ratio of formaldehyde to NO2 (FNR) has been used as an indicator to identify NO x -limited versus NO x -saturated O3 formation regimes. Quan...