Black carbon in air over northern regions of Russia: Sources and spatiotemporal variations

Аннотация

A model is used to estimate black carbon (BC) concentrations in air over different regions of the Russian North in 2000–2013. We discuss different BC physical sources in the atmosphere (anthropogenic sources and wildfires), emissions from these sources on the territory of Russia (according to different data), and estimate their contributions to BC concentration in air over Russian Arctic regions during winter and summer. This is done using satellite data on BC emissions to the atmosphere (GFED, MACCity, and others), as well as our estimates based on official statistical data of the Russian Federation. Long-range BC transport in the atmosphere was analyzed by the method of back trajectory statistics of air mass transport, developed previously using ARL NOAA data (HYSPLIT model). In the near-ground air over northern regions of the Russian Federation, the contributions of anthropogenic BC sources predominate over those from wildfires even during summer (except in Ust-Lena Nature Reserve), when contributions from remote anthropogenic sources are minimal. Average BC concentrations in air along the coast of the Arctic Ocean vary by two orders of magnitude, with the maximum in the region of Nenets Nature Reserve (the main source is nearby flares from casing-head gas combustion in regions of active hydrocarbon fuel production). The BC concentrations in air show large interannual and interseasonal variations; therefore, estimates according to multiyear average indices bear little information. Thus, measurements of BC content in air over a single site during one season or even one year should not serve a basis for long-term conclusions and forecasts pertaining to the entire region.