Wildfires in northern Eurasia affect the budget of black carbon in the Arctic – a 12-year retrospective synopsis (2002–2013)

Abstract

Abstract. In recent decades much attention has been given to the Arctic environment, where climate change is happening rapidly. Black carbon (BC) has been shown to be a major component of Arctic pollution that also affects the radiative balance. In the present study, we focused on how vegetation fires that occurred in northern Eurasia during the period of 2002–2013 influenced the budget of BC in the Arctic. For simulating the transport of fire emissions from northern Eurasia to the Arctic, we adopted BC fire emission estimates developed independently by GFED3 (Global Fire Emissions Database) and FEI-NE (Fire Emission Inventory – northern Eurasia). Both datasets were based on fire locations and burned areas detected by MODIS (Moderate resolution Imaging Spectroradiometer) instruments on NASA's (National Aeronautics and Space Administration) Terra and Aqua satellites. Anthropogenic sources of BC were adopted from the MACCity (Monitoring Atmospheric Composition and Climate and megacity Zoom for the Environment) emission inventory.During the 12-year period, an average area of 250 000 km2 yr−1 was burned in northern Eurasia (FEI-NE) and the global emissions of BC ranged between 8.0 and 9.5 Tg yr−1 (FEI-NE+MACCity). For the BC emitted in the Northern Hemisphere (based on FEI-NE+MACCity), about 70 % originated from anthropogenic sources and the rest from biomass burning (BB). Using the FEI-NE+MACCity inventory, we found that 102 ± 29 kt yr−1 BC was deposited in the Arctic (defined here as the area north of 67° N) during the 12 years simulated, which was twice as much as when using the MACCity inventory (56 ± 8 kt yr−1). The annual mass of BC deposited in the Arctic from all sources (FEI-NE in northern Eurasia, MACCity elsewhere) is significantly higher by about 37 % in 2009 (78 vs. 57 kt yr−1) to 181 % in 2012 (153 vs. 54 kt yr−1), compared to the BC deposited using just the MACCity emission inventory. Deposition of BC in the Arctic from BB sources in the Northern Hemisphere thus represents 68 % of the BC deposited from all BC sources (the remaining being due to anthropogenic sources). Northern Eurasian vegetation fires (FEI-NE) contributed 85 % (79–91 %) to the BC deposited over the Arctic from all BB sources in the Northern Hemisphere.We estimate that about 46 % of the BC deposited over the Arctic from vegetation fires in northern Eurasia originated from Siberia, 6 % from Kazakhstan, 5 % from Europe, and about 1 % from Mongolia. The remaining 42 % originated from other areas in northern Eurasia. About 42 % of the BC released from northern Eurasian vegetation fires was deposited over the Arctic (annual average: 17 %) during spring and summer.

Estimation of black carbon emissions from Siberian fires using satellite observations of absorption and extinction optical depths

“…16b): that is, about a quarter of the total BC emitted from Siberian 25 fires was transported into the Arctic. This estimate of the transport efficiency is comparable with that (about 30 %) obtained by Evangeliou et al (2016) for BC emitted from fires in Asia in the summer periods 2012-2013. Our results show that the transport efficiency was not constant across the different months.…”

“…For example, according to the FEI-NE inventory recently developed by Hao et al (2016), the annual BC emissions from fires in northern Eurasia in the period of 2002-2015 are, on average, a factor of 3.2 larger than those given by the GFED4 (van der Werf et al, 2017) inventory. Using 15 the FEI-NE inventory in the FLEXPART Lagrangian particle dispersion model, Evangeliou et al (2016) found the model results to be in a reasonable agreement with surface BC concentrations observed at several Arctic stations in the period [2002][2003][2004][2005][2006][2007][2008][2009][2010][2011][2012][2013]. On the other hand, a Bayesian inverse modeling analysis based on carbon isotope characterization of BC measurements at Tiksi (East Siberian Arctic) from April 2012 to April 2014 revealed that the best fit of the FLEXPART data to the observations was achieved by reducing the fire emissions given by GFED4 by 53 % (Winiger et al, 2017); this 20 estimate may, however, reflect uncertainties in the spatial distribution of the GFED4 emissions, as the sensitivity footprints in this particular study cover only a part of Siberia (Winiger et al, 2017).…”

Daily black carbon emissions from fires in northern Eurasia for 2002–2015

“…This BC emission inventory is essential for modeling air quality in high latitudes and ice and snow melting in the Arctic. The dataset has been used for studying the transport and deposition of BC on the Arctic from 2002 to 2013 (Evangeliou et al, 2016). The study found that approximately 8.2 ± 2.7 % of the BC emitted by northern Eurasian fires was deposited on Arctic ice during the period of 2002-2013, accounting for 45-78 % of the BC deposition from all the sources (Evangeliou et al, 2016).…”

“…The dataset has been used for studying the transport and deposition of BC on the Arctic from 2002 to 2013 (Evangeliou et al, 2016). The study found that approximately 8.2 ± 2.7 % of the BC emitted by northern Eurasian fires was deposited on Arctic ice during the period of 2002-2013, accounting for 45-78 % of the BC deposition from all the sources (Evangeliou et al, 2016). About 42 % of the BC emitted during spring and summer was deposited on Arctic ice, which is the most effective period for acceleration of ice and snow melting.…”

Source attribution of Arctic black carbon constrained by aircraft and surface measurements

“…Recent work by Stohl et al (2013) and Sand et al (2016) raised questions about prior studies by identifying the importance of seasonally varying residential heating and by suggesting a significant overlooked source from gas flaring in high-latitude regions. In addition to anthropogenic emissions, biomass burning is another important source of Arctic BC Warneke et al, 2009;Yttri et al, 2014;Evangeliou et al, 2016), yet its contribution remains uncertain. Furthermore, evidence is emerging that the BC observations to which many prior modelling studies compared may have been biased by 30 % (Sinha et al, 2017) or a factor of 2 due to other absorbing components in the atmospheric aerosol.…”