Harmful air pollution from Western Europe fires in July 2022 – With Copernicus Sentinel-3

Fires in Western Europe, Spain, France (e.g. Gironde and La Teste De Buch) are not only dangerous for the immediate surrounding population. But their emission of fine particles aerosols is of high concern. These smoke pollution can spread over long distance & impact on human health.

Sentinel-3 NRT Aerosol Optical Depth (AOD) 550 nm from the operational Copernicus Sentinel-3 NRT processor OSSAR-CS3, led by EUMETSAT.

Here an illustration with Copernicus Sentinel-3 Near Real Time (NRT – i.e. < 3h) Aerosol product from the EUMETSAT OSSAR-CS3 processor.

All information at: https://eumetsat.int/S3-nrt-l2-aerosol-product-collection-2-released-soon.

Public pictures available at #METIS: https://metis.eumetsat.int/aod

Stay tuned for the coming Collection 3 this Fall 2022!

Western Europe ravaged by fires during July 2022 – With Copernicus Sentinel-3 NRT

Fires are hitting us in Western Europe, especially in Spain, Portugal, and France. This is a very concerning situation for all surrounding population. We provide in Near Real Time (NRT – i.e. < 3h) information to all operational users thanks to OFRaP-CS3, the reference Copernicus Sentinel-3 NRT Fires processor of EUMETSAT.

Fires over Western Europe – July 2022 – observed with OFRaP-CS3 – Collection 2.0, the reference Copernicus Sentinel-3 NRT Fire processor led by EUMETSAT.

More information:

Stay tuned for Collection 2.1 upgrade, scheduled this Fall!

Saharan dust across Mediterranean

These days, in April 2022. quite a high load of dust particles can be clearly observed in the Mediterranean basin. They are notably visible with Copernicus Sentinel-3, see example of pictures from the Level 2 (l2) Near Real Time (NRT) aerosol product (by EUMETSAT from the OSSAR-CS3 Processor v3.0 – Collection 2.0)

These aerosols mostly originate from Sahara and travel toward South Europe.

More information?

  • Webpage on aerosol particles here
  • Copernicus Sentinel-3 NRT aerosol product Collection 2 from OSSAR-CS3 Processor v3.0 by EUMETSAT here

Working from home, Year 2!

Here we go for a 2nd year working from home again with EUMETSAT and Copernicus Sentinel-3 !

Although we have some hopes for a better health situation during 2021, it is clear we will have to continue to face turbulent moments.

I wish you All a very happy new year. Good luck to everyone going back to work! Let’s hope for a smooth transition from virtual meetings towards more and more real human interaction!

More information on:

  • The European Meteorological Satellite Agency EUMETSAT here
  • The Sentinel-3 mission here
  • The European Copernicus program here

Clouds with Copernicus Sentinel-3 SLSTR over Amazonia

RGB picture from Copernicus Sentinel-3 SLSTR-A over Amazonia on 30.11.2020. SWIR (1.6 um) in Red, and Visible (675 & 550 nm) in Blue & Green. Credit Picture from the SNAP tool box ESA/Brockmann Consult.

There is not only one type of clouds, but many of them, with diverse properties leading to various ways to visualize them when looking at our satellite measurements. Here an example with the Copernicus Sentinel-3 (S3) A Sea & Land Surface Temperature Radiometer (SLSTR) over Amazonia.

The Red-Green-Blue (RGB) picture below, of 30.11.2020 over Amazonia, combines the ShortWave InfraRed (SWIR) 1.6 um and the visible (674 & 550 nm). Water clouds with small droplets largely reflect at all channels & appear white. Snow & ice clouds strongly absorbs SWIR & appear cyan.

What about their altitude?

SLSTR has a special channel at 1.3 um in which water vapor (H2O) so much absorbs that no signal at the top of the atmosphere may be measured. Unless clouds at a very high altitude are present, shielding then a large fraction of the H2O column in the atmosphere. Consequently, a bright signal spikes up and elevated clouds shine!

Radiance at 1.3 um from Copenicus Sentinel-3 SLSTR-A over Amazonia on 30.11.2020. Credit Picture from the SNAP tool box ESA/Brockmann Consult.

From the picture above, snow & ice clouds are primary the highest one! Anything else lower, such as surface and fractional low clouds, seems “invisible”. They cannot be “seen”.

Winter has come in Europe – UV dose estimated from space

No doubt winter has come in Europe! The Earth inclination has changed.

As observed last Winter with GOME-2 UltraViolet (UV) measurements, a big change in the effective UV irradiance reaching the Earth surface is also seen over the day between last July and nowadays.

Here below is an example with the estimated reduced Vitamine D production in our skin as a direct consequence. These pictures are from the ESA / KNMI Tropospheric Emission Monitoring Internet Service (TEMIS). Satellite UV dose is computed from the assimilated global O3 – ozone field at local solar noon, and with surface downwelling solar (SDS) radiation & cloud information measured by the Meteosat Second Generation (MSG) satellites led by the EUMETSAT agency.


More information

  • WebBlog on Vitamin D estimated from GOME-2 UV measurements here
  • Clear-sky UV index forecast from the Tropospheric Emission Monitoring Internet Service (TEMIS) here, Credit ESA / KNMI

A new desert dust aerosol climatology from 9-year CALIOP observations over Asia – Very happy to co-author new ACP paper of Proestakis et al. (2018), from National Observatory of Athens (NOA)!

Spatial distribution of the seasonal mean CALIPSO AOD, D_AOD, optical depth difference between AOD and D_AOD (non-dust AOD), and the percentage of D_AOD with respect to the total AOD for the domain between 65–155 E and 5–55 N and for the period January 2007–December 2015 (Proestakis et al., 2018)

A recent work achieved by my colleagues of the National Observatory of Athens (NOA): 9 years of observations acquired by the CALIOP space-borne instrument were combined with EARLINET ground-based measurements to provide a climatology of desert dust particles over South and East Asia.

Having such a knowledge is important for many research studies focused on atmospheric transport and climate effect of dust.

You can see more details on my webpage here, and the paper of Proestakis et al. (2018) published in the Atmospheric Chemistry and Physics (ACP) journal here.

Don’t miss #GRS_TROPOMI event, a series of post on “why are we excited this week about #TROPOMI #Sentinel5P launch?!”


Why are we (I and my colleagues) that excited this week? Why is TROPOMI so much important for the new coming era in air quality & climate satellite era?

Throughout the week, we will post more information on our GRS TU Delft website and also be using the #GRS_TROPOMI on social media (Twitter and Instagram) as we explain more about the mission, its goals, and how it all works in relation to the goals and work being done in our department. The week will culminate with the Sentinel-5P launch event taking place at the Space Expo in Noordwijk.


More information?


20th OMI Science Meeting at NASA Goddard Space Institute

During 3 days, from 12 to 14 September 2017, I had the pleasure to attend, with my KNMI colleagues from the R&D satellite department, the 20th OMI Science Team Meeting hosted by NASA Goddard Space Institute in Greenbelt MD (close to Washington DC) in the USA.

Group picture at NASA, Goddard Space Institute, Greenbelt MD, Virginia, USA, 2017.09.13 in front the morning and A-Train satellite constellation, with all our OMI colleagues.

Despite its quite advance age for a satellite mission (13 years old!), OMI is still delivering remarkable measurements about our atmospheric composition and air quality. So many talks and discussions on the aerosol global record over cloud-free scenes and above clouds, decade global volcanic SO2 – Sulfur dioxide missions, the use of OMI data by air quality model simulations to inform air quality policy, the case studies on emissions monitoring and to support authorities and clean-tech industry, the new generation of the Quality Assurance For Essential Climate Variables (QA4ECV), the evolution in the ozone trends and related mechanisms, and of course the future with the forthcoming TROPOMI (Sentinel-5 Precursor) mission, TEMPO (NASA Geostationary) and TROPOLITE.

I was honoured to present the status of our work on the retrieval of aerosol layer height from the OMI visible band using machine learning technique, and the results with single day CALIOP aerosol along-track observations.

Chimot J., Veefkind P., van Ouwerkerk G., Vlemmix T., Levelt P., Aerosol layer height retrieval from OMI and neural network- Possibility for a 13-year time series?, 20th OMI Science Team Meeting, NASA Goddard, Greenbelt MD, Virginia, USA, 2017.09.12 (Source: https://www.researchgate.net/publication/319678283_Aerosol_layer_height_from_OMI_and_neural_network_Possibility_of_a_13-year_time_series)

Several nice social moments accompanied us during these 3 days:

  • The Nationals baseball game on Wednesday 13th September evening in Washington DC

  • The guided tour by NASA during lunch break, a great opportunity to see the control rooms of the Aura (OMI spacecraft!!), Aqua and Landsat missions!


I am very grateful to all the organizers for this inspiring meeting, and my current promotors (Dr. Pepijn Veefkind, Prof. Dr. Pieternel Levelt & Dr. Tim Vlemmix)!

In spite of being glad of having been part of this adventure, I cannot stop myself thinking this may have been my very last OMI conference, before finishing my current research project and starting new professional & personal adventures (still in satellite & atmospheric community of course!). But this last point will be specifically mentioned later in future weeks. Stay tuned!


More information?

Volcanic ‘plumerang’ or boomerang-like return of a volcanic plume with potential health-risk in Iceland

a) Location map of the Holuhraun eruption site (lava flow extent in red) and the two populated areas: Reykjavik, city capital area, and Reykjahlio. b) Holuhraun eruption during the January 2015 field campaign – activity exclusively effusive lava flow width ~ 50 m (Source: Ilyinska et al., 2017)

All volcanoes are on satellite watch due to their continuous gas emissions, in particular SO2 – Sulphur dioxide, and their impacts after eruptions on air quality and landslide risks. A new study, from University of Leeds (Ilyinska et al., 2017), has found a previously undetected potential health risk from the high concentration of small particles – aerosols – found in a boomerang-like return of a volcanic plume.

This study focused on the evolution of the plume chemistry from the 2014-2015 Icelandic Holuhraun lava field eruption and found a second type of plume that impacts air quality. This second plume had circled back to Icelandic cities and towns long after the health warning about the initial plume had been lifted.

The 2014–2015 Holuhraun eruption in Iceland, emitted ∼11 Tg of SO2 into the troposphere over 6 months, and caused one of the most intense and widespread volcanogenic air pollution events in centuries, exceeding hourly air quality standards (350 μg/m3) for SO2 on 88 occasions in Reykjahlíð town (100 km distance), and 34 occasions in Reykjavík capital area (250 km distance). Average daily concentration of volcanogenic sulphate particles exceeded 5μg/m3 on 30 days in Reykjavík capital area.

2 types of plume impacted the downwind populated areas:

  • The first type was characterised by high concentrations of both SO2 gas and fine particles,
  • The second type had a low SO2 gas concentration.

Ilyinska et al. (2017) suggest that this second type was a mature plume where sulphur had undergone significant gas-to-aerosol conversion in the atmosphere. This second plume had circled back to Icelandic cities and towns long after the health warning about the initial plume had been lifted. The return of this second mature plume, named as a ‘plumerang’, meant that the sulphur dioxide (SO2) levels were reduced and within the European Commission air quality standards and, therefore, there were no health advisory messages in place.

Dispersion model of hourly-mean SO2 (left) and sulphate aerosol (SO42−, right) surface mass concentrations (μg/m3) in September 2014. Panels (a) and (b) show a mature low Sgas/SAerosolplume reaching the Reykjavik capital area on 14 and 20 September 2014 (right), whereas SO2 mass concentrations are very low in the same location on those days (left). Panel (c) shows a ‘near-miss’ situation with a highly sulphate-rich mature plume narrowly passing the densely populated south-east coast of Iceland on 8 September 2014.

However, both types of plume were rich in fine aerosol, sulphate (on average ∼90% of the aerosol mass) and various trace species, including heavy metals. The fine size of the volcanic aerosol mass (~75–80%), combined with chemical components, have potential adverse implications for environmental and health impacts (e.g. exacerbating asthma attacks). The concentrations of these trace metals did not reduce as the plume matured and included heavy metals found in human-made air pollution that are linked to negative health effects. But, only the dispersion of volcanic SO2 gas was forecast in public warnings and operationally monitored during the eruption.

On at least 18 days during the 6-month long eruption the plumerang was in the capital city of Reykjavík, while the official forecast showed ‘no plume’.” (said lead author, Dr Ilyinskaya from the Institute of Geophysics and Tectonics at Leeds). “We spoke to people living in Reykjavik who described a burning sensation in the throat and eyes when the SO2 levels would have been well within air quality standards but the particle-rich plumerang would have been over the city.”

For the future, Ilyinska et al. (2017) strongly recommends that in future gas-rich eruptions both the young and mature plumes should be considered when forecasting air pollution and the dispersion and transport pattern of the plume.

The gas-to-particle conversion is quite typical for some so-called trace gases that are also precursor of aerosol particles, such as NO2 – Nitrogen dioxide, and SO2.


More information on:

  • WebPage on aerosol particles here
  • Previous WebPost on “Volcanoes on Sentinel-2 and OMI satellites watch – First global emission maps!” here
  • Ilyinska et al. (2017): Evgenia Ilyinskaya, Anja Schmidt, Tamsin A. Mather, Francis D. Pope, Claire Witham, Peter Baxter, Thorsteinn Jóhannsson, Melissa Pfeffer, Sara Barsotti, Ajit Singh, Paul Sanderson, Baldur Bergsson, Brendan McCormick Kilbride, Amy Donovan, Nial Peters, Clive Oppenheimer, Marie Edmonds. Understanding the environmental impacts of large fissure eruptions: Aerosol and gas emissions from the 2014–2015 Holuhraun eruption (Iceland). Earth and Planetary Science Letters, 2017; DOI: 10.1016/j.epsl.2017.05.025 here
  • “Volcanic ‘plumerang’ could impact human health” on geology page here


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