Air Quality III

In order to ensure that products delivered by air quality satellite sensors meet user requirements in terms of accuracy, precision and fitness for purpose, it is essential to develop a robust validation strategy relying on well-established and traceable reference measurements. In this context, the ESA Fiducial Reference Measurements for Ground-Based DOAS Air-Quality Observations (FRM₄DOAS) project is aiming at further harmonizing MAXDOAS measurements. Since it provides vertically-resolved information on atmospheric gases at an horizontal scale approaching the one from nadir backscatter satellite sensors, the ground-based MAXDOAS technique has been recognized as a valuable source of correlative data for validating space-borne observations of atmospheric species such as NO₂, HCHO, SO₂, O, etc.

In this presentation we describe the FRM4DOAS harmonization effort which includes three main activities: (1) the specification of best practices for MAXDOAS instrument operation, (2) the selection of state-of-the art retrieval algorithms, procedures, and settings, (3) the demonstration of a centralised rapid-delivery (6-24h latency) processing system for MAXDOAS instruments, to be operated within the international Network for the Detection of Atmospheric Composition Change (NDACC). The first phase of the project, which will end in November this year, focusses on the development of 3 key products: NO₂ vertical profiles, total O₃ columns, and tropospheric HCHO profiles. Demonstrated at 11 MAXDOAS pilot stations operated by project partners, the system is designed to allow seamless upscaling in terms of stations and data products. These activities will contribute to guarantee that homogenous, fully traceable, and quality-controlled datasets are generated from reference ground-based UV-vis instruments. The availability of such Fiducial Reference Measurements for air quality observations is critical for the validation of present and future satellite missions like atmospheric Sentinels (5p, 4, 5) in Europe, GEMS in Asia, and TEMPO in the US.

Space-borne earth observation has been important to monitor the earth condition and played a critical role in validating other instruments or modeling’s outputs. However, the data from satellite earth observation are usually very complex in terms of science contents, formats, and spatiotemporal granularities, making them difficult to use from many aspects.  NASA Goddard Earth Sciences Data and Information Services Center (GES DISC), one of the 12 official NASA data centers, archives and distributes rich collections of data from multiple satellite missions and model results.  The GES DISC is also the official archive center for data from the Ozone Monitoring Instrument (OMI) aboard NASA's Aura mission since 2004. Recently, the GES DISC has been evolving and improving its data management and services in order to promote NASA data to be easily discovered and accessed, as well as to facilitate interoperability.  We’ll show in this presentation how to explore and analyze NASA earth observation data for air quality through a suite of user-friendly tools - from Worldview to Giovanni, demonstrating in using this set of tools prepares us to serve the Sentinel 5P TROPOMI to the community.

Synergistic exploitation of simultaneous and independent measurements of atmospheric composition acquired by future mission Sentinel-4 and Sentinel-5, as well as from the Sentinel-5 precursor already launched on October 13^th, 2017, is the focus of the AURORA (Advanced Ultraviolet Radiation and Ozone Retrieval for Application) study, a three year project funded by the Horizon 2020 framework program of the European Union.

AURORA investigates the potential of a novel approach for the combination of complementary information from multiple sources about atmospheric Ozone vertical distribution from the surface to the top of the atmosphere and for subsequent calculation of associated products, such as tropospheric partial columns and ultraviolet surface radiation. For the first time to our knowledge, the study examines the outcome of Data Assimilation Systems ingesting Ozone vertical profiles obtained by applying an innovative a posteriori data fusion method, the so called Complete Data Fusion, to synthetic datasets simulating the operational retrieval products expected from Low Earth Orbit and Geostationary Orbit measurements of the atmospheric Sentinels missions of the Copernicus Program.

First results from a series of assimilation experiments, which according to the AURORA plans are executed using the TM5 and the IFS data assimilation systems and adopting an incremental approach, are now available. The presentation will provide a synthetic summary of the AURORA activities and will be focusing on the results of the comparison between the assimilation of fused data and the assimilation of standard retrieval products from observations of a virtual atmospheric scenario, as resulting from the outcome of assimilation experiments conducted with TM5.

The assimilation experiments, currently on-going with TM5 and IFS data assimilation system, are including a run for assimilation of standard Ozone profiles retrieved from measurements by TEMPO (Tropospheric Emission Monitoring of Pollution) over North America and by GEMS (Geostationary Environment Monitoring Spectrometer) over Asia-Pacific. This is to check the impact of air mases outside the geographical coverage of Sentinel-4 onto the outcome of the assimilation systems.

We will be finally reporting the preliminary results will also be reported of the key aspect of the project aimed to link the scientific achievements of the AURORA study to applications and services. Examples of applications capable to use the advanced quality data for tropospheric Ozone and ultraviolet radiation at the surface produced by AURORA will be presented in some details.