Source contributions to Northern Hemisphere CO and black carbon during spring and summer 2008 from POLARCAT and START08/preHIPPO observations and MOZART-4

Abstract

Anthropogenic pollution and wildfires are main producers of carbon monoxide (CO) and black carbon (BC) in the Northern Hemisphere. High concentrations of these compounds are transported into the Arctic troposphere, influencing the ecosystem in high northern latitudes and the global climate. The global chemical transport model MOZART-4 is used to quantify the seasonal evolution of the contribution of CO and BC from different source regions in spring and summer 2008 by tagging their emissions. Aircraft observations from the POLARCAT experiments, in particular NASA ARCTAS, NOAA ARCPAC, POLARCAT-France, DLR GRACE and YAK-AEROSIB, as well as the NSF START08/preHIPPO experiments during Spring-Summer 2008 are combined to quantify the representation of simulated tracer characteristics in anthropogenic and fire plumes. In general, the model reproduces CO and BC well. Based on aircraft measurements and FLEXPART back-trajectories, the altitude contribution of emissions coming from different source regions is well captured in the model. Uncertainties of the MOZART-4 model are identified by comparing the data with model results on the flight tracks and using MOPITT satellite observations. Anthropogenic emissions are underestimated by about 10% in high northern latitudes in spring, and shortcomings exist in simulating fire plumes. The remote impact of East-Siberian fire emissions is underestimated for spring, whereas the impact of Southeast Asian fire emissions to mid-latitude CO values is overestimated by the model. In summer, mid-latitude CO values agree well between model and observations, whereas summer high latitude East-Siberian fire emissions in the model are overestimated by 20% in comparison to observations in the region. On the other hand, CO concentrations are underestimated by about 30% over Alaska and Canada at altitudes above 4 km. BC values are overestimated by the model at altitudes above 4 km in summer. Based on MOZART-4, with tagged CO and BC tracers, anthropogenic emissions of Asia, Europe and the US have the largest contribution to the CO and BC in mid- and high latitudes in spring and summer. Southeast Asian, Chinese and Indian fires have a large impact on CO pollution in spring in low latitudes with a maximum between 20° and 30°, whereas Siberian fires contribute largely to the pollution in high latitudes, up to 10% in spring and up to 30% in summer. The largest contributions to BC values in high latitudes are from anthropogenic emissions (about 70%). CO and BC have larger mass loadings in April than in July, as a result of photochemistry and dynamics

Sources of carbonaceous aerosols and deposited black carbon in the Arctic in winter-spring: implications for radiative forcing

“…Asian pollution dominates the source of anthropogenic BC in the Arctic tropospheric column, but less so in surface air. Our model Asian contribution to Arctic BC in spring is higher than previous studies (Koch and Hansen, 2005;Shindell et al, 2008;Tilmes et al, 2011). This reflects our higher Asian emission inventory, constrained by observations at Chinese sites as discussed in Sect.…”

“…A number of CTM studies have investigated the sources of BC in the Arctic, but there are large disagreements among models and discrepancies with observations Koch et al, 2009b;Tilmes et al, 2011). Emissions in East Asia have grown rapidly in the past two decades and some work has pointed out an impact on winter-spring Arctic BC concentrations, especially in the free troposphere (Koch and Hansen, 2005;Shindell et al, 2008;Tilmes et al, 2011).…”

“…Emissions in East Asia have grown rapidly in the past two decades and some work has pointed out an impact on winter-spring Arctic BC concentrations, especially in the free troposphere (Koch and Hansen, 2005;Shindell et al, 2008;Tilmes et al, 2011). However, Stohl (2006) found little wintertime Asian influence over the Arctic either at the surface or in the free troposphere.…”

Airborne hydrogen cyanide measurements using a chemical ionisation mass spectrometer for the plume identification of biomass burning forest fires

“…For example, large boreal forest fires in Russia from 2002 to 2003 were responsible for global growth rates of many trace gases including carbon dioxide and methane (Kasischke et al, 2005;Yurganov et al, 2005;, but also to contribute to climate change (Damoah et al, 2004;Vivchar et al, 2010;Tilmes et al, 2011).…”

Acetylene (C<sub>2</sub>H<sub>2</sub>) and hydrogen cyanide (HCN) from IASI satellite observations: global distributions, validation, and comparison with model

“…MOZART-4 simulations of numerous species (CO, O 3 and related tracers including C 2 H 2 and HCN) have been previously compared to in situ and satellite observations and used to track the intercontinental transport of pol- lution (e.g. Emmons et al, 2010b;Pfister et al, 2006Pfister et al, , 2008Pfister et al, , 2011Tilmes et al, 2011;Clarisse et al, 2011b;Wespes et al, 2012;Viatte et al, 2015). The surface anthropogenic (including fossil fuel and biofuel) emissions used here were taken from the inventory provided by D. Streets and University of Iowa and created for the Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS) campaign (see http://bio.cgrer.uiowa.edu/arctas/emission.html for more information).…”