Wildfire smoke in the Siberian Arctic in summer: source characterization and plume evolution from airborne measurements

Abstract

Abstract. We present airborne measurements of carbon dioxide (CO 2 ), carbon monoxide (CO), ozone (O 3 ), equivalent black carbon (EBC) and ultra fine particles over NorthEastern Siberia in July 2008 performed during the YAK-AEROSIB/POLARCAT experiment. During a "golden day" (11 July 2008) a number of biomass burning plumes were encountered with CO mixing ratio enhancements of up to 500 ppb relative to a background of 90 ppb. Number concentrations of aerosols in the size range 3.5-200 nm peaked at 4000 cm −3 and the EBC content reached 1.4 µg m −3 . These high concentrations were caused by forest fires in the vicinity of the landing airport in Yakutsk where measurements in fresh smoke could be made during the descent. We estimate a combustion efficiency of 90 ± 3% based on CO and CO 2 measurements and a CO emission factor of 65.5±10.8 g CO per kilogram of dry matter burned. This suggests a potential increase in the average northern hemispheric CO mixing ratio of 3.0-7.2 ppb per million hectares of Siberian forest burned. For BC, we estimate an emission factor of 0.52 ± 0.07 g BC kg −1 , comparable to values reported in the literature. The emission ratio of ultra-fine particles (3.5-200 nm) was 26 cm −3 (ppb CO) −1 , consistent with other airborne studies.The transport of identified biomass burning plumes was investigated using the FLEXPART Lagrangian model. Based on sampling of wildfire plumes from the same source but with different atmospheric ages derived from FLEXPART, Correspondence to: J.-D. Paris (jean-daniel.paris@lsce.ipsl.fr) we estimate that the e-folding lifetimes of EBC and ultra fine particles (between 3.5 and 200 nm in size) against removal and growth processes are 5.1 and 5.5 days respectively, supporting lifetime estimates used in various modelling studies.

Tropical biomass burning smoke plume size, shape, reflectance, and age based on 2001–2009 MISR imagery of Borneo

“…4) and more persistent, smoldering peat-fueled fires in Borneo than in North America. A study of Siberian smoke events finds ages ranging from 1 to 13 days with mean 5.5 days (Paris et al, 2009), an order of magnitude greater than ages obtained here. However, these smoke events are not associated with a source fire, and in some cases are located thousands of kilometers from the nearest active fires, so we would classify them as smoke clouds, not plumes (Tosca et al, 2011).…”

“…Following the convention described in Tosca et al (2011), we would characterize this smoke as arising from "smoke clouds" rather from than "smoke plumes," as it is not associated with a clear fire source. As expected, older smoke clouds are found further from observed fire locations (Paris et al, 2009). Using a procedure similar to ours, Val Martin et al (2010) found that North American smoke plumes (i.e., clearly differentiated and associated with a fire source) have a median age of 2 h. This study estimates, for the first time, the distribution of plume ages from regularly occurring open fire-generated plumes.…”

“…Smoke clouds and other regions of aged smoke reside significantly higher than their plumes of origin (e.g., McKendry et al, 2011;Paris et al, 2009;Guan et al, 2010;Tosca et al, 2011). In Borneo smoke plumes, relative and absolute height initially decrease down-plume before increasing toward the plume end (Fig.…”

“…drought), the similarities in height distribution about the ABL suggest that processes governing the vertical distribution of plumes can be similar in geographically disparate regions. Aged plumes no longer associated with a clear fire source (hereinafter called smoke clouds, as per Tosca et al, 2011) can reach significantly greater heights, with Californian smoke several days old reaching 5 km (McKendry et al, 2011), while Siberian smoke events averaging 5.5 days old reached from 1.5 to 6 km (Paris et al, 2009). Additionally, smoke clouds are often located significantly higher than predicted by their aerosol indices (Guan et al, 2010), and higher than their plumes of origin (Tosca et al, 2011).…”

“…Siberian smoke observed in 2008 had ages of 1 to 13 days, with a mean of 5.5 days (Paris et al, 2009). This smoke was observed hundreds of kilometers from active fires.…”