Advanced Ultraviolet Radiation and Ozone Retrieval for Applications (AURORA): A Project Overview

With the launch of the Sentinel-5 Precursor (S-5P, lifted-off on 13 October 2017), Sentinel-4 (S-4) and Sentinel-5 (S-5)(from 2021 and 2023 onwards, respectively) operational missions of the ESA/EU Copernicus program, a massive amount of atmospheric composition data with unprecedented quality will become available from geostationary (GEO) and low Earth orbit (LEO) observations. Enhanced observational capabilities are expected to foster deeper insight than ever before on key issues relevant for air quality, stratospheric ozone, solar radiation, and climate. A major potential strength of the Sentinel observations lies in the exploitation of complementary information that originates from simultaneous and independent satellite measurements of the same air mass. The core purpose of the AURORA (Advanced Ultraviolet Radiation and Ozone Retrieval for Applications) project is to investigate this exploitation from a novel approach for merging data acquired in different spectral regions from on board the GEO and LEO platforms. A data processing chain is implemented and tested on synthetic observations. A new data algorithm combines the ultraviolet, visible and thermal infrared ozone products into S-4 and S-5(P) fused profiles. These fused products are then ingested into state-of-the-art data assimilation systems to obtain a unique ozone profile in analyses and forecasts mode. A comparative evaluation and validation of fused products assimilation versus the assimilation of the operational products will seek to demonstrate the improvements achieved by the proposed approach. This contribution provides a first general overview of the project, and discusses both the challenges of developing a technological infrastructure for implementing the AURORA concept, and the potential for applications of AURORA derived products, such as tropospheric ozone and UV surface radiation, in sectors such as air quality monitoring and health.

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Validation of TROPOMI nadir ozone profile retrievals: Methodology and first results

10.5194/egusphere-egu21-7385 ◽

2021 ◽

Author(s):

Arno Keppens ◽

Jean-Christopher Lambert ◽

Daan Hubert ◽

Steven Compernolle ◽

Tijl Verhoelst ◽

...

Keyword(s):

Near Infrared ◽

Stratospheric Ozone ◽

Estimation Method ◽

Optimal Estimation ◽

Data Retrieval ◽

Atmospheric Composition ◽

Retrieval Algorithm ◽

Validation Data ◽

Ozone Profile ◽

Early Afternoon

Part of the space segment of EU&#8217;s Copernicus Earth Observation programme, the Sentinel-5 Precursor (S5P) mission is dedicated to global and European atmospheric composition measurements of air quality, climate and the stratospheric ozone layer. On board of the S5P early afternoon polar satellite, the imaging spectrometer TROPOMI (TROPOspheric Monitoring Instrument) performs nadir measurements of the Earth radiance within the UV-visible and near-infrared spectral ranges, from which atmospheric ozone profile data are retrieved. Developed at the Royal Netherlands Meteorological Institute (KNMI) and based on the optimal estimation method, TROPOMI&#8217;s operational ozone profile retrieval algorithm has recently been upgraded. With respect to early retrieval attempts, accuracy is expected to have improved significantly, also thanks to recent updates of the TROPOMI Level-1b data product. This work reports on the initial validation of the improved TROPOMI height-resolved ozone data in the troposphere and stratosphere, as collected both from the operational S5P Mission Performance Centre/Validation Data Analysis Facility (MPC/VDAF) and from the S5PVT scientific project CHEOPS-5p. Based on the same validation best practices as developed for and applied to heritage sensors like GOME-2, OMI and IASI (Keppens et al., 2015, 2018), the validation methodology relies on the analysis of data retrieval diagnostics &#8211; like the averaging kernels&#8217; information content &#8211; and on comparisons of TROPOMI data with reference ozone profile measurements. The latter are acquired by ozonesonde, stratospheric lidar, and tropospheric lidar stations performing network operation in the context of WMO's Global Atmosphere Watch and its contributing networks NDACC and SHADOZ. The dependence of TROPOMI&#8217;s ozone profile uncertainty on several influence quantities like cloud fraction and measurement parameters like sun and scan angles is examined and discussed. This work concludes with a set of quality indicators, enabling users to verify the fitness-for-purpose of the S5P data.

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Stratospheric ozone changes under solar geoengineering: implications for UV exposure and air quality

Atmospheric Chemistry and Physics ◽

10.5194/acp-16-4191-2016 ◽

2016 ◽

Vol 16 (6) ◽

pp. 4191-4203 ◽

Cited By ~ 19

Author(s):

Peer Johannes Nowack ◽

Nathan Luke Abraham ◽

Peter Braesicke ◽

John Adrian Pyle

Keyword(s):

Air Quality ◽

Atmospheric Carbon Dioxide ◽

Climate Model ◽

Stratospheric Ozone ◽

Surface Ozone ◽

Atmospheric Composition ◽

Specific Humidity ◽

Uv Exposure ◽

Solar Radiation Management ◽

Global Mean

Abstract. Various forms of geoengineering have been proposed to counter anthropogenic climate change. Methods which aim to modify the Earth's energy balance by reducing insolation are often subsumed under the term solar radiation management (SRM). Here, we present results of a standard SRM modelling experiment in which the incoming solar irradiance is reduced to offset the global mean warming induced by a quadrupling of atmospheric carbon dioxide. For the first time in an atmosphere–ocean coupled climate model, we include atmospheric composition feedbacks for this experiment. While the SRM scheme considered here could offset greenhouse gas induced global mean surface warming, it leads to important changes in atmospheric composition. We find large stratospheric ozone increases that induce significant reductions in surface UV-B irradiance, which would have implications for vitamin D production. In addition, the higher stratospheric ozone levels lead to decreased ozone photolysis in the troposphere. In combination with lower atmospheric specific humidity under SRM, this results in overall surface ozone concentration increases in the idealized G1 experiment. Both UV-B and surface ozone changes are important for human health. We therefore highlight that both stratospheric and tropospheric ozone changes must be considered in the assessment of any SRM scheme, due to their important roles in regulating UV exposure and air quality.

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Validation of TROPOMI nadir ozone profile retrievals: Methodology and first results

10.5194/egusphere-egu2020-7868 ◽

2020 ◽

Author(s):

Arno Keppens ◽

Daan Hubert ◽

Jean-Christopher Lambert ◽

Steven Compernolle ◽

Tijl Verhoelst ◽

...

Keyword(s):

Near Infrared ◽

Stratospheric Ozone ◽

Estimation Method ◽

Optimal Estimation ◽

Data Retrieval ◽

Atmospheric Composition ◽

Retrieval Algorithm ◽

Validation Data ◽

Ozone Profile ◽

Early Afternoon

Part of the space segment of EU&#8217;s Copernicus Earth Observation programme, the Sentinel-5 Precursor (S5P) mission is dedicated to global and European atmospheric composition measurements of air quality, climate and the stratospheric ozone layer. On board of the S5P early afternoon polar satellite, the imaging spectrometer TROPOMI (TROPOspheric Monitoring Instrument) performs nadir measurements of the Earth radiance within the UV-visible and near-infrared spectral ranges, from which atmospheric ozone profile data are retrieved. Developed at the Royal Netherlands Meteorological Institute (KNMI) and based on the optimal estimation method, TROPOMI&#8217;s operational ozone profile retrieval algorithm has recently been upgraded. With respect to early retrieval attempts, accuracy is expected to have improved significantly, also thanks to recent updates of the TROPOMI Level-1b data product. This work reports on the initial validation of the improved TROPOMI height-resolved ozone data in the troposphere and stratosphere, as collected both from the operational S5P Mission Performance Centre/Validation Data Analysis Facility (MPC/VDAF) and from the S5PVT scientific project CHEOPS-5p. Based on the same validation best practices as developed for and applied to heritage sensors like GOME-2, OMI and IASI (Keppens et al., 2015, 2018), the validation methodology relies on the analysis of data retrieval diagnostics &#8211; like the averaging kernels&#8217; information content &#8211; and on comparisons of TROPOMI data with reference ozone profile measurements. The latter are acquired by ozonesonde, stratospheric lidar, and tropospheric lidar stations performing network operation in the context of WMO's Global Atmosphere Watch and its contributing networks NDACC and SHADOZ. The dependence of TROPOMI&#8217;s ozone profile uncertainty on several influence quantities like cloud fraction and measurement parameters like sun and scan angles is examined and discussed. This work concludes with a set of quality indicators enabling users to verify the fitness-for-purpose of the S5P data.

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Advanced Ultraviolet Radiation and Ozone Retrieval for Applications—Surface Ultraviolet Radiation Products

Atmosphere ◽

10.3390/atmos11040324 ◽

2020 ◽

Vol 11 (4) ◽

pp. 324

Author(s):

Antti Lipponen ◽

Simone Ceccherini ◽

Ugo Cortesi ◽

Marco Gai ◽

Arno Keppens ◽

...

Keyword(s):

Ultraviolet Radiation ◽

Synthetic Data ◽

Software Tool ◽

Ground Truth ◽

Low Earth Orbit ◽

Surface Radiation ◽

Lower Atmosphere ◽

The European Union ◽

Operational Environment ◽

Uv Index

AURORA (Advanced Ultraviolet Radiation and Ozone Retrieval for Applications) is a three-year project supported by the European Union in the frame of its H2020 Call (EO-2-2015) for “Stimulating wider research use of Copernicus Sentinel Data”. The project addresses key scientific issues relevant for synergistic exploitation of data acquired in different spectral ranges by different instruments on board the atmospheric Sentinels. A novel approach, based on the assimilation of geosynchronous equatorial orbit (GEO) and low Earth orbit (LEO) fused products by application of an innovative algorithm to Sentinel-4 (S-4) and Sentinel-5 (S-5) synthetic data, is adopted to assess the quality of the unique ozone vertical profile obtained in a context simulating the operational environment. The first priority is then attributed to the lower atmosphere with calculation of tropospheric columns and ultraviolet (UV) surface radiation from the resulting ozone vertical distribution. Here we provide details on the surface UV algorithm of AURORA. Both UV index (UVI) and UV-A irradiance are provided from synthetic satellite measurements, which in turn are based on atmospheric scenarios from MERRA-2 (Modern-Era Retrospective analysis for Research and Applications, Version 2) re-analysis. The UV algorithm is implemented in a software tool integrated in the technological infrastructure developed in the context of AURORA for the management of the synthetic data and for supporting the data processing. This was closely linked to the application-oriented activities of the project, aimed to improve the performance and functionality of a downstream application for personal UV dosimetry based on satellite data. The use of synthetic measurements from MERRA-2 gives us also a “ground truth”, against which to evaluate the performance of our UV model with varying inputs. In this study we both describe the UV algorithm itself and assess the influence that changes in ozone profiles, due to the fusion and assimilation, can cause in surface UV levels.

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4. Atmospheric composition

The Atmosphere: A Very Short Introduction ◽

10.1093/actrade/9780198722038.003.0004 ◽

2017 ◽

pp. 65-92

Author(s):

Paul I. Palmer

Keyword(s):

Ultraviolet Radiation ◽

Atmospheric Aerosols ◽

Stratospheric Ozone ◽

Ultraviolet B ◽

Atmospheric Composition ◽

Earth’S Atmosphere ◽

Stratospheric Ozone Layer ◽

History Of ◽

Earth's Atmosphere ◽

The Impact

Nitrogen, oxygen, and argon represent more than 99.9% of the air we breathe. But Earth’s atmosphere hasn’t always had that composition—it is on at least its third distinctive atmosphere. ‘Atmospheric composition’ provides a brief history of Earth’s atmosphere, before considering the two most important regions of the atmosphere for human survival—the stratosphere and troposphere. The stratospheric ozone layer shields harmful ultraviolet-B light penetrating to the surface, thereby protecting humans and ecosystems from harmful ultraviolet radiation. The troposphere is where billions of people live and breathe. It is also where air pollutants are emitted, wildfires burn, vegetation grows, and where the oceans exchange gases. The impact of atmospheric aerosols and greenhouse gases is also discussed.

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Observations of surface radiation and stratospheric processes at Thule Air Base, Greenland, during the IPY

Annals of Geophysics ◽

10.4401/ag-6382 ◽

2014 ◽

Vol 57 (3) ◽

Author(s):

Giovanni Muscari ◽

Claudia Di Biagio ◽

Alcide di Sarra ◽

Marco Cacciani ◽

Svend Erik Ascanius ◽

...

Keyword(s):

Water Vapour ◽

Surface Albedo ◽

Middle Atmosphere ◽

Stratospheric Ozone ◽

Surface Radiation ◽

Atmospheric Composition ◽

Radiation Budget ◽

The Arctic ◽

Western Coast ◽

International Polar Year

Ground-based measurements of atmospheric parameters have been carried out for more than 20 years at the Network for the Detection of Atmospheric Composition Change (NDACC) station at Thule Air Base (76.5°N, 68.8°W), on the north-western coast of Greenland. Various instruments dedicated to the study of the lower and middle polar atmosphere are installed at Thule in the framework of a long standing collaboration among Danish, Italian, and US research institutes and universities. This effort aims at monitoring the composition, structure and dynamics of the polar stratosphere, and at studying the Arctic energy budget and the role played by different factors, such as aerosols, water vapour, and surface albedo. During the International Polar Year (IPY), in winter 2008-2009, an intensive measurement campaign was conducted at Thule within the framework of the IPY project “Ozone layer and UV radiation in a changing climate evaluated during IPY” (ORACLE-O3) which sought to improve our understanding of the complex mechanisms that lead to the Arctic stratospheric O3 depletion. The campaign involved a lidar system, measuring aerosol backscatter and depolarization ratios up to 35 km and atmospheric temperature profiles from 25 to 70 km altitude, a ground-based millimeter-wave spectrometer (GBMS) used to derive stratospheric mixing ratio profiles of different chemical species involved in the stratospheric ozone depletion cycle, and then ground-based radiometers and a Cimel sunphotometer to study the Arctic radiative budget at the surface. The observations show that the surface radiation budget is mainly regulated by the longwave component throughout most of the year. Clouds have a significant impact contributing to enhance the role of longwave radiation. Besides clouds, water vapour seasonal changes produce the largest modification in the shortwave component at the surface, followed by changes in surface albedo and in aerosol amounts. For what concerns the middle atmosphere, during the first part of winter 2008-2009 the cold polar vortex allowed for the formation of polar stratospheric clouds (PSCs) which were observed above Thule by means of the lidar. This period was also characterized by GBMS measurements of low values of O3 due to the catalytic reactions prompted by the PSCs. In mid-January, as the most intense Sudden Stratospheric Warming event ever observed in the Arctic occurred, GBMS and lidar measurements of O3, N2O, CO and temperature described its evolution as it propagated from the upper atmosphere to the lower stratosphere.

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Air Quality Measurement and Analysis by TROPOMI, OMI, MLS, OMPS, TANSO-FTS , and MERRA-2

10.5194/egusphere-egu21-8076 ◽

2021 ◽

Author(s):

Jane Zeng ◽

Suhung Shen ◽

James Johnson ◽

Andrey Savtchenko ◽

Lena Iredell ◽

...

Keyword(s):

Air Quality ◽

Greenhouse Gases ◽

Near Infrared ◽

Stratospheric Ozone ◽

Environmental Data ◽

Atmospheric Composition ◽

Electromagnetic Spectrum ◽

Monitoring Instrument ◽

Data Collections ◽

Atmospheric Constituent

Global and regional air quality measurements play an important role in the everyday life of people, inasmuch as atmospheric constituents such as ozone (O3), carbon monoxide (CO), nitrogen dioxide (NO2), sulfur dioxide (SO2), methane (CH4), and aerosols may cause severe threats to human health and agriculture productivity. Space-based sensors on satellites are able to detect these atmospheric constituents directly and indirectly at high spatial and temporal scales. The TROPOspheric Monitoring Instrument (TROPOMI) on the Copernicus Sentinel-5 Precursor (Sentinel-5P) satellite provides measurements of O3, NO2, SO2, CH4, CO, formaldehyde (HCHO), aerosols, and cloud in ultraviolet-visible (UV-VIS), near infrared (NIR), and shortwave infrared (SWIR) spectral ranges. The Ozone Monitoring Instrument (OMI) aboard the Aura mission measures ozone, aerosols, clouds, surface UV irradiance, and trace gases including NO2, SO2, HCHO, BrO, and OClO using UV electromagnetic spectrum bands. The Ozone Mapping Profiler Suite (OMPS) on the Suomi National Polar-Orbiting Partnership (Suomi-NPP or SNPP) provides environmental data products including O3, NO2, SO2, and aerosols. The Microwave Limb Sounder (MLS) on Aura has been monitoring atmospheric chemical species (CO, volcanic SO2, O3, N2O, BrO), temperature, humidity, and cloud ice since 2004. MLS measurements help understand stratospheric ozone chemistry, and the effects of air pollutants injected into the upper troposphere and low stratosphere. The Thermal And Near infrared Sensor for carbon Observation - Fourier Transform Spectrometer (TANSO-FTS) on the Greenhouse Gases Observing Satellite (GOSAT) covers a wide spectral range from VIS to thermal infrared (TIR), which enables remote observations of the greenhouse gases carbon dioxide (CO2) and CH4. Furthermore, atmospheric constituent data are also available in the second Modern-Era Retrospective analysis for Research and Applications (MERRA-2) NASA's atmospheric reanalysis data collection. MERRA-2 uses an upgraded version of the Goddard Earth Observing System Model, version 5 (GEOS-5) data assimilation system, enhanced with more aspects of the Earth system. The NASA Goddard Earth Sciences Data and Information Services Center (GES DISC) supports over a thousand data collections in the focus areas of Atmospheric Composition, Water & Energy Cycles, and Climate Variability. Some of these data collections include atmospheric composition products from the ongoing TROPOMI, OMI, OMPS, MLS, TANSO-FTS, and MERRA-2 missions and projects. The GES DISC web site (https://disc.gsfc.nasa.gov) provides multiple tools designed to help data users easily search, subset, visualize, and download data from these diverse sources in a unified way. We will demonstrate several methodologies employing these tools to monitor air quality.

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An update on ozone profile trends for the period 2000 to 2016

10.5194/acp-2017-391 ◽

2017 ◽

Cited By ~ 1

Author(s):

Wolfgang Steinbrecht ◽

Lucien Froidevaux ◽

Ryan Fuller ◽

Ray Wang ◽

John Anderson ◽

...

Keyword(s):

Climate Model ◽

Stratospheric Ozone ◽

Atmospheric Composition ◽

Data Sets ◽

Ozone Profile ◽

Ozone Trends ◽

Climate Model Simulations ◽

Stratospheric Cooling ◽

Ozone Depleting Substances ◽

The Tropics

Abstract. Ozone profile trends over the period 2000 to 2016 from several merged satellite ozone data sets and from ground-based data by four techniques at stations of the Network for the Detection of Atmospheric Composition Change indicate significant ozone increases in the upper stratosphere, between 35 and 48 km altitude (5 and 1 hPa). Near 2 hPa (42 km), ozone has been increasing by about 1.5 % per decade in the tropics (20° S to 20° N), and by 2 to 2.5 % per decade in the 35° to 60° latitude bands of both hemispheres. At levels below 35 km (5 hPa), 2000 to 2016 ozone trends are smaller and not statistically significant. The observed trend profiles are consistent with expectations from chemistry climate model simulations. Using three to four more years of observations and updated data sets, this study confirms positive trends of upper stratospheric ozone already reported, e.g., in the WMO/UNEP Ozone Assessment 2014, or by Harris et al. (2015). The additional years, and the fact that nearly all individual data sets indicate these increases, give enhanced confidence. Nevertheless, a thorough analysis of possible drifts and differences between various data sources is still required, as is a detailed attribution of the observed increases to declining ozone depleting substances and to stratospheric cooling. Ongoing quality observations from multiple independent platforms are key for verifying that recovery of the ozone layer continues as expected.

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A Distributed Modular Data Processing Chain Applied to Simulated Satellite Ozone Observations

Remote Sensing ◽

10.3390/rs13020210 ◽

2021 ◽

Vol 13 (2) ◽

pp. 210

Author(s):

Marco Gai ◽

Flavio Barbara ◽

Simone Ceccherini ◽

Ugo Cortesi ◽

Samuele Del Bianco ◽

...

Keyword(s):

Data Processing ◽

Uv Radiation ◽

Processing System ◽

Simulated Data ◽

General Purpose ◽

Low Earth Orbit ◽

Atmospheric Composition ◽

General Purpose Technologies ◽

Processing Chain ◽

Novel Approach

Remote sensing of the atmospheric composition from current and future satellites, such as the Sentinel missions of the Copernicus programme, yields an unprecedented amount of data to monitor air quality, ozone, UV radiation and other climate variables. Hence, full exploitation of the growing wealth of information delivered by spaceborne observing systems requires addressing the technological challenges for developing new strategies and tools that are capable to deal with these huge data volumes. The H2020 AURORA (Advanced Ultraviolet Radiation and Ozone Retrieval for Applications) project investigated a novel approach for synergistic use of ozone profile measurements acquired at different frequencies (ultraviolet, visible, thermal infrared) by sensors onboard Geostationary Equatorial Orbit (GEO) and Low Earth Orbit (LEO) satellites in the framework of the Copernicus Sentinel-4 and Sentinel-5 missions. This paper outlines the main features of the technological infrastructure, designed and developed to support the AURORA data processing chain as a distributed data processing and describes in detail the key components of the infrastructure and the software prototype. The latter demonstrates the technical feasibility of the automatic execution of the full processing chain with simulated data. The Data Processing Chain (DPC) presented in this work thus replicates a processing system that, starting from the operational satellite retrievals, carries out their fusion and results in the assimilation of the fused products. These consist in ozone vertical profiles from which further modules of the chain deliver tropospheric ozone and UV radiation at the Earth’s surface. The conclusions highlight the relevance of this novel approach to the synergistic use of operational satellite data and underline that the infrastructure uses general-purpose technologies and is open for applications in different contexts.

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Ozone changes under solar geoengineering: implications for UV exposure and air quality

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-15-31973-2015 ◽

2015 ◽

Vol 15 (21) ◽

pp. 31973-32004 ◽

Cited By ~ 4

Author(s):

P. J. Nowack ◽

N. L. Abraham ◽

P. Braesicke ◽

J. A. Pyle

Keyword(s):

Air Quality ◽

Atmospheric Carbon Dioxide ◽

Climate Model ◽

Stratospheric Ozone ◽

Surface Ozone ◽

Atmospheric Composition ◽

Uv Exposure ◽

Solar Radiation Management ◽

Solar Geoengineering ◽

Radiation Management

Abstract. Various forms of geoengineering have been proposed to counter anthropogenic climate change. Methods which aim to modify the Earth's energy balance by reducing insolation are often subsumed under the term Solar Radiation Management (SRM). Here, we present results of a standard SRM modelling experiment in which the incoming solar irradiance is reduced to offset the global mean warming induced by a quadrupling of atmospheric carbon dioxide. For the first time in an atmosphere–ocean coupled climate model, we include atmospheric composition feedbacks such as ozone changes under this scenario. Including the composition changes, we find large reductions in surface UV-B irradiance, with implications for vitamin D production, and increases in surface ozone concentrations, both of which could be important for human health. We highlight that both tropospheric and stratospheric ozone changes should be considered in the assessment of any SRM scheme, due to their important roles in regulating UV exposure and air quality.

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