Research homepage Julien Chimot

Canada wildfires from space and ground – Seeing beyond the flames: a series of observations

Since July, the province of British Columbia (BC), west coast of Canada, has been impacted by massive and violent wildfires. Such events are visually impressive. They can be a constructive force by maintaining the overall health and functioning of the forest ecosystem, but also a destructive force due to devastating impacts on the local population, soil and our atmosphere: e.g. visibility reduction, air quality deterioration caused by smoke fine particles (aerosols) that are harmful for health population and on a longer term, climate.

CBay — **Left:** the view over the Haro Strait on a typical summer’s day. (Source: Cordova Bay Golf Course) **Right:** the view on 4 August, 2017. (Photo: Alexander Izett)

These effects can easily be seen by different “eyes”. While BC is known for its clean, fresh air, the visibility reduction occurs as the increased concentration of smoke particles leads to more extinction of the sunlight passing through the atmosphere. This results in the formation of haze and the dark grey smoke that we see. The particles can also attract water, acting as condensation nuclei for droplet formation and a subsequent further reduction in visibility as fog and clouds form.

VancouverSkyline — The Vancouver skyline and surrounding mountains obscured by haze, as seen from the Tsawwassen Ferry Terminal. (Photo: Jonathan Izett; 18 July, 2017)

Smoke accumulating in the Coastal Mountain range. (Photo: Jonathan Izett; 1 August, 2017)

Sun — The sun through the smoke near Victoria, BC (Photo: Alexander Izett; 5 August, 2017)

Although the fires themselves are fairly localized in the interior of BC, their overall impact is not, with the smoke traveling far away from the source region – up to thousands of kilometers! Atmospheric and fire emission models are used to predict the amount and trajectory of smoke according to the prevailing circulation and dispersion patterns allowing for air quality forecasts and warnings, such as the Government of Canada’s wildfire smoke prediction system: FireWork.

2017081100_V2017081200Z_gemmach_PM2.5_diffplot_surface_continental_24 — FireWork forecast of small particulate matters (PM2.5) concentration at the surface level from forest fire sources for 0000 UTC on 12 August, 2017. Notice the particles are carried far from their origin in central BC: to northern and central Canada; the US mid-west; and along the west coast of North America, all the way to Mexico (Source: https://weather.gc.ca/firework/).

Satellite observations are vital to monitor such disasters. Not only do they provide an overview image from the top of the atmosphere of the raging fires, which already gives spectacular maps, they also allow detection of the substances released in the air by these episodes and follow their dispersion. This is vital for predicting the impact of air masses far away from the fire sources. Below are some illustrations of these satellite maps over the last 10 days.

AquaTrueColournasa-worldview-2017-07-31-to-2017-08-08 — Natural-color images from MODIS-Aqua sensor, over east Canada within the period of 2017.07.31-2017.08.08. Red points indicate actively burning areas identified from MODIS, on-board Terra and Aqua platforms. Smokes stretch very far away from these points (Source: https://worldview.earthdata.nasa.gov).

Optical images like MODIS sensors (on-board Terra & Aqua platforms) capture the thick smokes directly linked to the fires: such plumes can extent to several hundreds thousands of kilometres. Moreover, measurements in thermal infrared spectrum allow detection of the actively burning areas.

AquaAODnasa-worldview-2017-07-31-to-2017-08-08 — Aerosol particles, suspended in air, monitored *via* MODIS-Aqua sensor, over east Canada within the period of 2017.07.31-2017.08.08. Here, the Aerosol Optical Depth (AOD) is plotted, a proxy of aerosol load or amount. Values are in the range of 0.5 (yellow-orange) – 2 (dark red – large amount of particles) (Source: https://worldview.earthdata.nasa.gov).

The integrated amounts of aerosol particles that are suspended in the atmosphere can be quantified, and their horizontal distribution monitored. This is an important input for air quality models in charge of predicting the air quality for populations.

OMIUVAInasa-worldview-2017-07-31-to-2017-08-08 — Some satellite sensors can distinguish some aerosol – particle – types. Here, the so-called UVAI index derived from the OMI-Aura sensor, over Canada within the period of 2017.07.31-2017.08.08, indicate in orange-red a large presence of very dark (*i.e.* absorbing) particles (UVAI values in the range of 2-5) (Source: https://worldview.earthdata.nasa.gov).

Knowing the type of these particles (i.e. whether they are dark or brighter) is of great importance for scientists and researchers. This directly gives insights on how these aerosols affect our atmosphere radiation, and consequently our climate on the long-term. Satellite sensors measuring light in the UV such as the Dutch-Finnish OMI mission, on-board the NASA Aura platform, provides with an important index (here named UV Absorbing Index or UVAI) to identify absorbing (i.e. very dark) aerosol particles on a daily-global coverage.

IASI_CO_Canada_2017 — CO – Carbon monoxide total column from IASI sensor, on-board Metop-A, [1×10^18 molec/cm2] (Source: http://www.pole-ether.fr/etherTypo/index.php?id=1789&L=1).

Finally, wildfires do not only release smoke and particles, which already pose a problem for human respiratory health, but also a mix of toxic gases. One of the most important is CO – Carbon monoxide. Infrared sensors such as the European IASI mission, on-board Metop-A and B, quantify everyday the amount of CO present in the atmosphere. On some specific days in August, concentration values were comparable to those associated with African and South-American fires.

Many more compounds can be additionally measured over wildfires: CO2 – Carbon dioxide, NO2 – Nitrogen dioxide for some specific fire episodes etc…

This post was written by Julien Chimot and my colleague Jonathan Izett. Find more information on Jonathan via his Linkedin profile, and his website on his research work focused on the formation, evolution and prediction of fog in the atmospheric boundary layer.

More information?:

Government of Canada’s FireWork forecast here
BC Air Quality Health Risk here
NASA satellite images available on Worldview website here
IASI CO products available on the EUMETSAT Atmospheric COmposition Satelite Application Facilities (AC SAF) here
The UVAI index, identifying dark / absorbing particles, from OMI sensor here
Global news on British Columbia wildfires in Canada here
Aerosol particles WebPage
CO – Carbon monoxide WebPage
NO2 – Nitrogen Dioxide WebPage
Wildfires observed in France by MODIS WebPost

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!

S5P — Sentinel-5 Precursor at Airbus in UK (Source: http://www.bbc.com/news/science-environment-40675444)

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: https://www.linkedin.com/pulse/water-quality-from-space-eva-stierman

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

Wildfires in French Mediterranean region observed from MODIS

nasa-worldview-2017-07-24-to-2017-07-27 — Natural-color composite image acquired from the NASA MODIS-Aqua sensor over the Provence area, France from 2014.07.24 to 2017.07.26. Smoke from the blazes and wildires. Red points indicate the actively burning zones detected from the MODIS fire thermal anomaly products (Source: https://worldview.earthdata.nasa.gov)

Since mid-July, huge wildfires have raged across south-eastern France, forcing more than 10,000 residents and holidaymakers to flee homes and campsites overnight. Some fires also occurred in the northern part of Corsica. Hundreds of firefighters have been deployed but the battles remain difficult and challenging due to strong winds, dry areas and extreme warm weather.

These impressive fires were spotted by the American Modis-Aqua satellite through the dispersed smoke particles on the last days. The burning areas are not only located within the forests but also next to the coasts and some famous villages (e.g. Saint-Tropez and Bormes-Les-mimosas in the Var department).

Evacuated people are forced to sleep on the beach of Bormes-les-Mimosas in the Var region in southern France. Fires often ravage the French Riviera but this year the area is experiencing an exceptionally hot and dry summer, making it particularly vulnerable. Moreover, current investigations suspect malice causes in this event. The blazes have destroyed brush and vegetation in about 4,000 hectares (15 square miles) of land along France’s Mediterranean coast.

Fires in Bormes-Les-Mimosas,

Mediterranean French coast area. (Source: http://www.telegraph.co.uk/news/2017/07/26/wildfire-hits-southern-france-forcing-10000-evacuations/)

image-download — Natural-color composite image acquired from the NASA MODIS-Aqua sensor over north-east French Corsica region, France on 2014.07.24 . Smoke from the blazes and wildires. Red points indicate the actively burning zones detected from the MODIS fire thermal anomaly products (Source: https://worldview.earthdata.nasa.gov).

More information?:

Natural-color of MODIS images here
Article in The Telegraph here
MODIS active fire and burned area products 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: https://earthobservatory.nasa.gov/NaturalHazards/view.php?id=90008)

New Earth night-lights mapsfor 2016 made by NASA’s Goddard Space Flight Center from Suomi-NPP satellite (Source: https://earthobservatory.nasa.gov/NaturalHazards/view.php?id=90008)

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 https://storymaps.esri.com/stories/2017/lights-on-lights-out/index.html).

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: http://www.temis.nl/airpollution/no2col/no2regioomimonth_v2.php?Region=9&Year=2016&Month=12).

Global Earth night-lights maps for 2016 made by NASA’s Goddard Space Flight Center from Suomi-NPP satellite(Source: https://climate.nasa.gov/climate_resources/86/).

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

Improved temperature dataset from satellites show a faster warming of our climate

New tropospheric temperature satellite record compared with NASA surface measurements. Produced by Carbon Brief using data from RSS and NASA. (Source: https://www.carbonbrief.org/major-correction-to-satellite-data-shows-140-faster-warming-since-1998)

Long-time series of satellite datasets, such from the American MSU and AMSU sensors, are an important asset to evaluate the temperate changes in our climate system, in particular at the tropospheric level. Climate sceptics, supported by politicians (e.g. Ted Cruz during the last American campaign), have long relied on satellite datasets to claim that global warming is overestimated.

An improved temperature dataset made by researchers from Remote Sensing Systems (RSS), based in California, have released a substantially revised version of their lower tropospheric temperature record. After correcting a lot of problems due to decaying orbit of satellites, the new data record not only shows:

a 36% faster warming since 1979 and nearly 140% faster (i.e. 2.4 times larger) warming since 1998;
and a much better agreement with the global surface temperature record produced by NASA.

This new reprocessed satellite data record substantially undermines the argument of climate change deniers. But still more works are necessary to evaluate the gaps with the projected climate models.

See for more information:

The article explained in detail on CarbonBrief here
“Ted Cruz keeps saying that satellites don’t show global warming. Here’s the problem” from the Washington Post here
Paper of Mears et al., 2017: A satellite-derived lower tropospheric atmospheric temperature dataset using an optimized adjustment for diurnal effects here
The FAQ about the new tropospheric temperature dataset update by Dr. Carl Mears here

Homepage updates

Quite some updates the last weeks on my research homepage. Feel free to check them and comment!

A new page hast been created in the “Atmosphere composition” section: CO2 – Carbon dioxide:What is CO2? How is CO2 produced? Who are the largest CO2 emitters? Why shall we observe atmosphere CO2? A typical CO2 satellite map? Some reference CO2 satellite missions / products? More details here
We have gladly collaborated at GRS – TU Delft in our group with some students on very interesting projects related to atmospheric composition, air quality remote sensing, satellites (e.g. OMI, MODIS, CALIOP, Sentinel-3), climate and neural networks. Check here!
A new section Events highlight available here
A WebPage on the past ESA project SIROCCO achieved with my NOVELTIS colleagues and European consortium here
Update links of reference websites (used or for just more interests) here

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