Updated calculations carried out by atmosphere and climate scientists at NILU show that smoke from the forest fires in Canada is still drifting in over Norway.
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“As long as the forest fires are ongoing, we can expect that some of the smoke will reach Norwayâ€, says senior researcher Nikolaos Evangeliou. “During the next few days, the smoke cloud will likely hit countries further south in Europe.â€
Nikolaos Evangeliou and senior scientist Sabine Eckhardt have created an updated simulation that shows how smoke and soot particles from Canada are carried through the atmosphere. The forecast extends until 13 June.
In the simulation, the smoke emission from Canada is shown as a cloud moving over a world map. The different colors of the cloud tell the amount of particles the cloud contains. The yellow areas of the cloud signal where there are the most soot particles in the air.
“When the smoke reaches Europe, the number of particles is much lowerâ€, says Evangeliou. – “This means that we can possibly see the smoke as a faint haze, and perhaps notice the smell of smoke. But the number of particles is so low that it should not cause any health hazards.â€
The forest fires in Canada are still raging, and the emission of smoke and ash into the atmosphere is very strong. When Evangeliou, Eckhardt and their colleagues create such simulations, they first download datasets created with the help of satellite observations. These show how powerful the emission is. Then, they model the dispersion of these emissions in the atmosphere. For this, they use meteorological data from the Global Forecast System (GFS) of the National Centers for Environmental Prediction (NCEP) in the US.
The data are fed into an atmospheric model called FLEXPART, to calculate how emissions disperse further. In addition, they use data on expected precipitation, as rain, hail and snow can remove such particles from the atmosphere and discharge them to the ground.
When Eckhardt wants to look at how smoke from the forest fires moves in the atmosphere, she first defines the area where the smoke is coming from. The location of active fires and their radiative power can be seen from satellite instruments. An example of satellite view from June 4 is shown in the figure below.
Eckhardt must also define how high the smoke rises in the atmosphere, a crucial detail that stems from the fire intensity. For the forest fires in Canada, the injection altitude was variable with a highest value identified at around 4 kilometers up in the air. Such a definition of width, length and height for an area is called an emission box.
In FLEXPART, Eckhardt can fill the emission box with various virtual particles or gases. Some particles are heavy enough to sink quickly, others are so light that they can be carried thousands of miles before hitting the ground.
Since we are now interested in the forest fires in Canada, they filled the emission box in FLEXPART with smoke particles. These particles are so small that as long as there is no precipitation, they can float far before sinking.
“We have actually seen cases where smoke particles from large forest fires are carried through the atmosphere all the way around the globeâ€, she says.
On Wednesday 7 June, smoke particles from Canada were picked up by NILU’s monitoring instruments at the Birkenes observatory in the south of Norway.
“The monitoring instruments cannot say anything about the area these particles originate from. For that, we use FLEXPART modeling, among other thingsâ€, explains senior engineer Are Bäcklund. “We also have instruments that can determine the particle source. Particles have a kind of ‘fingerprint’ that reveals whether they come from, for example, forest fires, industrial pollution or sandstorms.â€
On Thursday 8 June, both the FLEXPART modeling and Copernicus modeling show that the smoke cloud from Canada has moved north towards Svalbard.
On Svalbard stands the Zeppelin observatory, where NILU also has measuring instruments that can detect particle pollution in the atmosphere.
“Our instruments measure 24 hours a day, 365 days a yearâ€, says Bäcklund. “When the smoke from the Canadian forest fires moves in over Svalbard, we see it the minute it hits.â€
Over the next few days, the NILU scientists will follow the development of the fires in Canada closely. For this, they also use satellite data to gain a better understanding of the spatial distribution of the gases. An example is carbon monoxide (CO) and particles from the Sentinel-5P satellite.
Eckhardt and Evangeliou can also disclose that due to the large number of particles in the atmosphere, the light is refracted more than usual. This can produce extra strong colors in the sky, giving us some spectacular sunsets. ■