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Siberian Smoke on the Move

Siberian Smoke on the Move

Farmers in the steppe of southern Russia have an old tradition of burning dried grass in the spring to fertilize the soil for the new growing season. That tradition became a nightmare in April 2015 when large numbers of agricultural fires escaped the control of their handlers and spread rapidly across the dry landscape. As wildfires raged across the region, media and citizens captured remarkable and frightening scenes of flames and smoke engulfing grasslands, villages, and roadways. The view from above has been similarly dramatic.

Typically, wildfire smoke stays relatively close to the surface in the boundary layer, the part of the atmosphere (generally lower than 1 kilometer) where the shape of the ground has a significant impact on winds. In April 2015, some of the escaped fires in Siberia got a boost from unusually warm temperatures and from the emergence of a baroclinic cyclone near Chita, Russia. The storm fanned the flames so much that it lofted smoke well into the middle and upper troposphere, where strong upper-level winds dispersed it widely.

The image above offers a unique view of the smoke and its position in the atmosphere. The strip of orange data was collected overnight on April 15, 2015, by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) instrument on the CALIPSO satellite. The instrument sent pulses of laser light down through the atmosphere and recorded the reflections to generate a vertical profile of the smoke plume. CALIOP detected smoke between 4 and 10 kilometers (2 and 6 miles), fairly high for a wildfire.

For context, the black and white image above the CALIPSO data shows the storm clouds and smoke plume as observed by Aqua MODIS around the same time. Aqua can sense the amount of thermal energy radiating from the atmosphere and from land surfaces, making it possible to distinguish some features at night. Cooler areas in the image are dark, while warmer areas are bright. The brightest areas appear to be ocean water, while darker areas are clouds, smoke, and the land surface. Note that the image has been rotated so that north is to the right; this is to line the image up with the north-south flight path (marked in red) of CALIPSO.

Once the smoke was lofted high in the atmosphere, strong upper-level winds carried it over the Sea of Okhotsk and eventually across the Pacific Ocean. On April 15, 2015, the Visible Infrared Imaging Radiometer Suite (VIIRS) on Suomi NPP captured an image (above) showing smoke mixed with clouds from the cyclone moving over the Sea of Okhotsk. While this high-level smoke is subtle, it has darkened the clouds over Khabarovsk Territory and Sakhalin slightly. A more obvious band of smoke, which was significantly lower in the atmosphere, is also visible streaming over Inner Mongolia, North Korea, and South Korea. The VIIRS image was acquired about 12 hours before the CALIPSO image at the top of the page. The same weather system produced an intense dust storm in Beijing.

Several other satellite instruments, including the Ozone Mapping & Profiler Suite (OMPS) on Suomi NPP and the MODIS instruments on Aqua and Terra captured imagery of smoke moving across the Pacific. By April 18, large amounts of smoke had reached the western coast of North America, as shown in the Aqua MODIS image below.

“Events like this have occurred before, but it has been a few years since satellites have captured one so well,” noted Naval Research Laboratory meteorologist Mike Fromm.

NASA Earth Observatory image by Jesse Allen, using expediated data provided by the CALIPSO team. Natural colour VIIRS data from the Suomi National Polar-orbiting Partnership. Suomi NPP is the result of a partnership between NASA, the National Oceanic and Atmospheric Administration, and the Department of Defense. Caption by Adam Voiland, with information from the PryoCb Yahoo group.

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