Evolution and radiation effects of the extreme smoke pollution over the european part of Russia in the summer of 2010

Abstract

Using aerospace monitoring data we performedspatiotemporal analysis of the evolution of smokeaerosol during the period of forest and peat bog fires onthe European territory of Russia (ETR) in the summerof 2010. It is shown that the spatial structure of theETR smoke pollution and its temporal variations wereclosely related to the processes of largescale atmospheric dynamics. In the period from August 5 toAugust 9 the region of maximum smoke pollutionmade a complete clockwise rotation around Moscowremaining at a distance of 200–650 km from the megacity, which prevented even a greater smoke pollutionof Moscow (compared with the pollution observedduring these days). Statistical characteristics of variations in the aerosol optical depth (AOD, ) at the wavelength of 0.55 m (0.55) over the ETR during the wildfires are presented. The mass content of smoke aerosolin the atmospheric column is evaluated as well. We alsoestimated regional mean shortwave radiative forcing ofthe smoke aerosol at the top and at the bottom of theatmosphere. The distributions of the aerosol radiativeforcing (ARF) over the ETR during the fires are presented and their significant spatial inhomogeneitiesare revealed. MODIS AOD data are validated by comparison with AOD data obtained at the AERONETstation Zvenigorod.A spacious and longliving blocking anticyclonethat settled over the ETR in the summer of 2010 [1]radically changed the thermal and hydrologicalregimes of the region [2]. A long drought facilitatedthe appearance and spreading of the forest and peatbog fires, which led to strong aerosol and gas pollutionof the atmosphere in the region that lasted many days[3–6]. The high concentration of smoke aerosol in theair caused strong changes in the radiation regime ofthe atmosphere [7].Unlike the groundbased data, the satellite AODdata along with the estimates of the local smoke loading allow to study the geographical distribution of thesmoke aerosol and its time evolution, obtain estimatesof the spatially distributed (regional) radiative effectsof the smoke, and also retrieve the spatial pattern ofthe ARF. This information is needed for correct estimates of aerosol particle emission during the fires,solution of various climatic problems, and testing ofchemical transport models. In this work, we use thesatellite AOD observations from the MODIS instruments [8, 9] to study the spatiotemporal evolution ofthe AOD and shortwave radiation forcing of the smokeaerosol during the forest an d peat bog fires in the ETRin the summer of 2010. We assume that the ETR is theterritory bounded by coordinates 47°–65° N and 25°–55° E with an area of approximately 3.6 mln. km