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

Seeing electricity energy through night-time pictures

Night-time pictures of of 2018.10.07 observed by the NASA SUOMI NPP VIIRS sensor. Credit NASA Worldview Earthdata

I am never tired of watching at night-time pictures from NASA SUOMI satellite worldview. We can directly observe how much our western societies depend on electricity.

While the last Intergovernmental Panel on Climate Change (IPPC) report just got released, and stresses the urgency to act extremely quickly for limiting the global warming close to 1.5 deg, one should keep in mind that the worldwide electricity sector is one of the highest source of CO2  – Carbon dioxide released in the atmosphere. Do we want to keep our lights on? Let’s ban then coal gas & use electricity sources with low CO2  – Carbon dioxide emissions (including nuclear!).


More information?

  • The last IPCC report here
  • NASA-NOAA Satellite Reveals New Views of Earth at Night here

2017 seen from the sky – A personal selection

2017 is about finishing, 2018 is going to take over. Here is a personal retrospective view on 2017 with a subjective selection of remarkable satellite images.

Wildfires across the globe

Massive wildfires spread across parts of the world such as Chile; Western Canada and the United States; Portugal and Spain; France and even Greenland in 2017. The most recent once, California’s Thomas Fire, was even the largest wildfire of the year in the state. MODIS AquaAqua, Sentinel-2 and many other space-borne instruments reveal these episodes and their intensity. Due to the on-going changes in our climate, it is unfortunately expected that such fires will occur again in 2018, perhaps even stronger.

Red Sun, dust and smoke in Europe

In October 2017, a unique combination of 2 independent events – fires in Portugal & Spain, and a tropical storm – brought dust and smoke all over Europe leading then an unusual red Sun observed in France, UK, Finland and the Netherlands. These events were observed notably by OMI, GOME-2 and MODIS Aqua. More information in No borders for particles! – Red Sun, Saharan dust and smoke over whole Europe

A huge 100-Mile Iceberg breaking away from Antarctica

An iceberg of 120 miles long and with a weight of more than a trillion metric tons broke away in Antarctica last July. It was floating along the so-called Larsen-C ice shell and was carefully monitored by worldwide scientists, notably by Sentinel-1 images. This event rose even more concerns about how Antarctica is evolving in the context of a warmer climate and sea level perturbations.

Such event was well documented in near-real time by our colleague Stef Lhermitte from GRS-TU Delft.

Sentinel-1 B image acquired on 12 July 2017 shown the break off of he Larsen-C ice shelf, spawning one of the largest icebergs on record and changing the outline of the Antarctic Peninsula forever. Credit ESA (Source:

California wildfire lights in, Puerto Rico lights out

Satellite images of Earth “night lights” have been a curiosity for the public and a tool of fundamental research for at least 25 years. New global maps have been released by NASA’s Goddard Space Flight Center using the NASA-NOAA Suomi National Polar-orbiting Partnership (Suomi-NPP) satellite. Some of them depict in an impressive way some dramatic episodes of this year: Hurricane Maria struck Puerto Rico, a commonwealth of the United States, leaving the island devastated and all but destroying its power grid; the fast-moving fire that swept into Ventura, California, on December 5, 2017. looking as bright as the urban Los Angeles area.

Monitoring hurricanes

Given the important images, it is important to monitor the mentioned hurricanes and tropical storms. Satellites like Sentinel-3 allow not only to characterise them (e.g. in terms of brightness temperature) but also to follow their displacement.

The Ophelia storm as observed by the Sentinel-3 A satellite. Left: image on 11.102017, when Hurricane Ophelia was about 1300 km south-west of the Azores islands and some 2000 km off the African coast. Right: Brightness temperature of the clouds at the top of the storm, some 12–15 km above the ocean, range from about –50°C near the eye of the storm to about 15°C at the edges on17.10.2017. Copyright ESA (Source:

First air quality images from TROPOMI aboard Sentinel-5 Precursor (P)

Of course, how not to finish this series without mentioning Sentinel-5 P and its instrument TROPOMI? Many persons waited for it for more than 10 years. I personally heard about it the first time some 5-6 years ago, and then waited for its launch during the last 4 years while working on my research with its predecessor OMI. And finally, just a few months before the end of my current job, Sentinel-5 P was launched, a very happy Friday 13th (October)!

With its unique high spatial resolution (7 x 3.5 km2) and top design sensor, this is the very first European operational mission dedicated to atmospheric composition within the Copernicus programme. The instrument is still under calibration until April 2018, being prepared for the developed services, and many works have to be done to derive accurate estimations of toxic gases and particles in the atmosphere. But the very 1st revealed maps of NO2 – Nitrogen dioxide, SO2 – Sulphur dioxide, O3 – Ozone, CO – Carbon monoxide are already outstanding. What is mostly remarkable are the very fine scale structures of all the pollution plumes already visible.

No doubt that the next months and years will be promising for this instrument. Air pollutants will be seen in much more detail than what has been accomplished before. And, while these first results demonstrate the sophistication of the satellite’s instrument, they certainly bring the issue of air pollution sharply into focus. Even though I am going to work on another project in 2018, I will keep a close eye on the next results from TROPOMI S5P.

And in addition look at this NO2 global animation – an average over a couple of days from TROPOMI S5P. Credit KNMI / ESA here.



And so many other pictures of 2017 that I could have posted here, but I invite you to have a look to my past posted weblog pages.

Looking forward to more images and discoveries from space in 2018! And I wish to everyone reading this a Merry Christmas and a very healthy & happy new year!

Must read – A warning from 15,000 world scientists


25 years ago, in 1992, 1700 independent scientists already told us in their “World Scientists – Warning to Humanity – 1st Notice”. And yet, it seems that was not sufficient. This month, a second notice was submitted, this time by about 15,000 worldwide scientists. And the message is still quite clear: “the world is going toward catastrophic biodiversity loss and untold amounts of human misery” and we have little time to act before avoiding this.

This may sound like an unrealistic, even irrational alarmist message. But it is worth reminding that, since its beginning, science work (and scientists) is beforehand based on observations, facts, interpretations with evaluation of uncertainties, implementing models that are then continuously and thoroughly evaluated  by confronting with observations.

This article is relatively short and very simple to read. No need to be an expert, every citizen can easily understand all the messages. I think this is the duty to each of us to take some minutes for reviewing it, and then thinking about our actions. Especially, the causes are nowadays well identified: rapid population growth, deforestation, agricultural production, and rising greenhouse gases from burning fossil fuels that has triggered and driven our climate change.

For this last one, in spite of continuous denial and unjustified claims (especially in the USA), the odds from IPCC and COP23 are pretty clear: CO2 – Carbon dioxide and CH4 – Methane amount in the atmosphere are historically unique, and the emissions keep increasing. Some of these increases are also even observable from space.

Atmospheric levels of CH4 – Methane from 2003 to 2005 and 2008 to 2010, showing  increased concentrations in the latter dataset (in red). The newly released ‘Climate Research Data Package No. 3’ covers more than one decade (2003–14) of atmospheric data products used to get information on the sources and sinks of carbon dioxide and methane. The data products are available through the website: (Source ESA:


A positive sign: stratospheric O3 – Ozone hole over Antarctic is recovering. If our actions have allowed to create and then solved this problem, then we can still do something, at every level, about the greenhouse gases.

Several journals and websites forwarded this article. But I have the feeling yet it could reach more and more people and lead to further discussions and actions in our societies. Hope this is not too late…


More information?

  • Ripple et al., 2017: Full articles World Scientists’ Warning to Humanity, 1st and 2nd notices here. You can also endorse the 2017 article here
  • European Space Agency (ESA): CO2 – Carbon dioxide and CH4 – Methane on the rise here
  • CO2 – Carbon dioxide WebPage here
  • CH4 – Methane WebPage Here


Measuring CO2, temperature and humidity in our office



Since beginning summer, tests and works have been undertaken at our office at the Geoscience & Remote Sensing (GRS) department of TU Delft to improve temperature conditions while working. In order to support these tests, some measurements have been acquired.

And it is still very interesting to observe not only the temporal variability of temperature, CO2 – Carbon dioxide concentrations and relative humidity but also the apparent nice correlations between them! Especially, CO2 in our office and temperature seem to follow similar diurnal variation. Of course, these variables, at a such local scale, are also strongly dependent on external parameters such as wind transport, the number of people present in the room, whether the windows are open etc…


More information?

  • CO2 – Carbon dioxide, an important greenhouse gas and its impacts on our changing climate here


“Our house is burning and we are looking somewhere else” said French president Jacques Chirac in 2002 – Fires from Canada to Greenland in 2017

“Our house is burning and we are looking somewhere else. Nature mutilated, overexploited is not able to recover and we refuse to admit it. From North to South, it suffers from ill-development, and we are indifferent. Earth and humanity are in great peril and we are accountable” (from my own English translation).

Those were the words pronounced by our former French president in 2002 in Johannesburg (South-Africa) in 2002 during the Earth summit. The real French words pronounced were the following: “Notre maison brûle et nous regardons ailleurs. La nature, mutilée, surexploitée, ne parvient plus à se reconstituer et nous refusons de l’admettre. L’humanité souffre. Elle souffre de mal-développement, au nord comme au sud, et nous sommes indifférents. La terre et l’humanité sont en péril et nous en sommes tous responsables.”

Jacques Chirac, former French president of the Republic (1995-2007), at the Earth summit in Johannesburg in 2002 pronouncing the famous statement “Our house is burning and we are looking somewhere else”.

At that time, large wildfires were ravaging Australia and societies were debating on the responsibility of climate change. 15 years later, 2017, these words are somehow ringing a bell to me. When looking at all the twitter posts during the last 2 months, we quickly get the feeling that Earth is on fire.

Not only, British Colombia (Western Canada) is facing one of its worst wildfire season, France and other European countries (Portugal, Greece, Croatia) have been victims of raging forest fires this Summer, wildfire episodes are increasing in eastern Russia, but also a fire sparked in Greenland the last weeks, an odd occurrence for this island more known for ice.

Kalamos fires, in Greece, in August 2017 as seen by the COPERNICUS Sentinel-2 data (Source:

A series of blazes has burned in the vicinity of Kangerlussuaq, a small town that serves as a basecamp for researchers in the summer to access Greenland’s ice sheet and western glaciers. The largest fire has burned roughly 3,000 acres and sent smoke spiralling a mile into the sky, prompting hunting and hiking closures in the area, according to local news reports. There’s no denying that it’s weird to be talking about wildfires in Greenland because ice covers the majority of the island. Forests are basically non-existent and this fire appears to be burning through grasses, willows and other low-slung vegetation on the tundra that makes up the majority of the land not covered by ice.

Smoke from the Greenland fire seen in satellite images
copernicus sentinel -2b/pierre Markuse/ESA (Source:

Most of Greenland is covered by ice up to 3 kilometres thick but there is some tundra around the coastline. The wildfire is burning on tundra in the west of Greenland, near the small town of Sisimiut. The larger fire could be a result of melting permafrost, McCarty told Wildfire Today. As the once-frozen ground melts, the upper layers can dry out and become flammable if they are full of organic matter. Stef Lhermitte, a remote sensing expert at the Geoscience & Remote Sensing department (GRS) of Delft University of Technology (TU Delft) in the Netherlands, said there is evidence of fires burning in Greenland over the past 17 years of MODIS satellite records kept by NASA.

“It certainly is the biggest one in the satellite record,” says remote-sensing scientist Stef Lhermitte of Delft University of Technology in the Netherlands. That record only goes back to 2000, but it could well turn out to be the biggest wildfire in Greenland’s history. The fire, first spotted by a pilot on 31 July, has taken researchers by surprise.  His initial analysis of satellite observations suggests there have been a few small wildfires in Greenland since 2000 but that over the past three years there has been a huge increase in the area burning.

Smoke spotted over Greenland by plane (Source:


No doubt then that our house is burning. The question now is: where are we looking?


More information?

  • Canada wildfires from space and ground – Seeing beyond the flames: a series of observations here
  • Wildfires in French Mediterranean region observed from MODIS here
  • Stef Lhermite research: website & Twitter account
  • Video “Our home is burning” by former French President Jacques (subtitles in English) at the Earth summit in Johannesburg in 2002 here
  • Largest ever wildfire in Greenland seen burning from space here

  • There’s a Wildfire Burning in West Greenland Right Now, from Climate Central, here
  • Smoke and fire spotted spotted on 31st July 2017 by plane here

UK & EU’s Earth observation space – COPERNICUS – No Brexit!

OMI data tracking NO2 – Nitrogen dioxide emissions which come in large part from motor vehicle exhausts (OMI / KNMI)

This is good news! The collaboration between all European countries is of great importance to continue to ensure major step forwards in Earth observation scientific studies using satellite measurements. And the statement of UK to stay within European Union’s Copernicus Earth observation programme after Brexit is therefore more than welcome!

Sentinel-5 Precursor at Airbus in UK (Source:

Airbus UK contributed a lot to build TROPOMI. We are all exited, and looking forward to the forthcoming launch of Sentinel-5 Precursor mission, which includes the TROPOMI instrument. TROPOMI will allow the mapping of key air gas pollutants (e.g. NO2 – Nitrogen dioxide, CO – Carbon monoxide, SO2 – Sulphur Dioxide, O3 – Ozone etc…), aerosol particles, and climate green-houe gases (i.e. CH4 – Methane). This first operational European atmospheric space-borne sensor, within the COPERNICUS program, will acquire these images at an unprecedented spatial resolution of 7 km, compatible then with large urban areas.

More explanations are given in the interview given at BBC News by Dr. Pepijn Veefkind, Principal Investigator (PI) of TROPOMI, from the Royal Netherlands Meteorological Institute (KNMI) and Delft University Technology – GRS department. See the link here.


More information?

  • UK wants continued EU Copernicus participation + Interview of Dr. Pepijn Veefkind, PI of TROPOMI, here
  • Europe day: no atmospheric space activity without European collaboration WebPost
  • Counting down towards the launch of TROPOMI WebPost
  • TROPOMI website here
  • European COPERNICUS Earth Observation program here
  • NO2 – Nitrogen dioxode WebPage
  • CO – Carbon monoxide WebPage
  • CH4 – Methane WebPage
  • Aerosol particles WebPage


Water quality from space – Measurement campaign along Dutch monitoring lines by Eva Stierman

Scheveningen slowly disappearing on the horizon: picture by Eva Stierman copied from here:

Check out the article here from Eva Stierman, our GRS – TU Delft student, doing a measurement campaign along the Dutch monitoring lines for validating the water quality products delivered by satellite observations.

Eva is doing her Master thesis at Rijkswaterstaat (RWS) & DELTARES, with GRS – TU Delft, to validate Sentinel-3A OLCI level-1 and level-2 data products with in situ measurements of RWS. She recently left, from the harbor of Scheveningen, for a measurement campaign at several locations in the north of the Netherlands: the Rottumerplaat, Terschelling and Noordwijk monitoring lines.

Have a successful campaign Eva!

More information?

  • The article of Eva available here
  • Eva student profile here
  • Students projects that we have followed or supervised with our group at GRS – TU Delft here


Night lights and air pollution – Similar patterns seen from space?


New Earth night-lights map for 2016 made by NASA’s Goddard Space Flight Center from Suomi-NPP satellite (Source:
New Earth night-lights mapsfor 2016 made by NASA’s Goddard Space Flight Center from Suomi-NPP satellite (Source:

Atmospheric and surface satellite measurements are usually exploited on daylight to benefit from the Sun light. However, another application of satellite observations is more and more emerging: images of Earth’s dark side to monitor human lights. Night lights are generally a human phenomenon. As such, they can be considered as proxy of living standards and economic activity of our societies. “An illuminated place, sufficient to be detected by an orbiting satellite, represents the substantial influence we have on pushing back the darkness of the night-time sky.” (cf. ESRI on

Satellite images of Earth “night lights” have been a curiosity for the public and a tool of fundamental research for at least 25 years. New global maps have been released by NASA’s Goddard Space Flight Center using the NASA-NOAA Suomi National Polar-orbiting Partnership (Suomi-NPP) satellite.

The potential future applications of such products are quite numerous: to aid disaster response, to produce regular power outage maps and integrate the information into recovery efforts by first responders, to monitor unregulated or unreported fishing, reduce light pollution and help protect tropical forests and coastal areas with fragile ecosystems, and to improve global and regional estimates of carbon dioxide and pollutant emissions.

Indeed, impacts due to human activities (e.g. urbanization, out-migration, economic changes etc…) could be then better measured and interpreted with respect to energy (electricity) and the related production technologies. See for example the maps below: monthly NO2 (a key gas pollutant released by fossil-fuel burning activities) concentration in December 2016 as retrieved from the Dutch-Finnish OMI mission, and the night-lights in 2016 from Suomi-NPP. Quite some similar patterns no?

Could we do the same with other gases such as CO, CO2,  etc…?

Monthly OMI tropopsheric NO2 vertcial column density (Source:
Global Earth night-lights maps for 2016 made by NASA’s Goddard Space Flight Center from Suomi-NPP satellite(Source:

See more information:

  • NASA feature night lights database here
  • NASA sphere & animations here
  • OMI NO2 products available on the Dutch TEMIS website here
  • WebPages on NO2 here, CO here and CO2 here


Europe day: no atmospheric space activity without European collaboration

NH3 – Ammonia observations by IASI, for 6-9 April, 2015. Major emissions are observed in Bretagne, England, Spain and in the Pô valley. © Martin Van Damme (Free University of Bruxelles) (Source:

67 years ago, a 9th of May, through his historical speech, the French foreign minister Robert Schuman developed his vision of a European institution pooling and managing coal and steel production. His dream was to structure European nations around common goals to stop wars between the nations. Following this idea, a treaty was signed a year latter. This is considered as the beginning of our EU.

European space institutions (ESA, EUMETSAT) were born years later. Without collaborations between all the European countries, without the support of ESA & EUMETSAT (funding, management political etc..), we would not benefit from major space missions and their high-value data set on our atmosphere.

IASI (InfraRed Atmospheric Sounding Interferometer) is a relevant example: develloped by CNES (French space agency) and EUMETSAT, flying on the European MetOp series of weather satellites (A, B and C), acquiring temperature, humidity and 25 other atmospheric components, supporting worldwide Earth’s climate and air quality scientists.

Developed by CNES in partnership with Eumetsat, the IASI instrument (Infrared Atmospheric Sounding Interferometer) is flying on the European MetOp series of weather satellites. Besides acquiring temperature and humidity data, IASI also measures more than 25 other atmospheric components with high precision and is supporting the efforts of scientists monitoring Earth’s climate.

This successfully started with the European nations and their collaborations. This will only successfully continue with Europe. Happy Europe day!

More information?

  • Robert Schuman’s speech on 1950.05.09 here
  • The IASI space mission here
  • Recent NH3 – Ammonia hotspots detected in the world here
  • The European Space Agency (ESA) here
  • EUMETSAT here