**7. Fires above the European Part of Russia (EPR) under conditions of abnormal summer of 2010**

The spatial variations in the air turbidity factor according to ground-based measurement data from 18 solar radiometry stations within the territory (40°–70° N, 30°–60° E) in summer 2010. We have shown earlier (Makhotkina et al., 2005; Plakhina et al., 2007, 2009, 2010) that the spatial distribution of the aerosol optical depth (AOD) over the territory of Russia averaged over more than 30 years corresponds to the model of global atmospheric aerosol distribution over Eurasia and the satellite AOD monitoringresults, presented in the 3rd and 4th IPCC reports; it shows a decrease in the aerosol turbidity from southwest to northeast. The events of summer 2010 (abnormal heat and forest and peat fires) evidently changed both the average values of air turbidity and the character of its spatial variations. Therefore, our estimates are of interest in the analysis (All Russia Meeting, 2010) of the situation on the European Part of Russia (EPR) in summer 2010. Fig. 9 presents the coordinates of solar radiometry stations on the EPR (Luts'ko et al., 2001); data from it were used in this work. The long-term annual average (over a "post-volcanic" period of 1994–2009 years) values *Т*postfor summer months and the corresponding monthly values *Т*2010for 2010 are given in Table 4, along with the monthly average maxima of *Т*and the relative difference (%) *D* = (*Т*2010 – *Т*post)/*Т*post. As it is seen, the average July and August *Т*in 2010 and in the "postvolcanic" period differ by –6% and +4%, respectively (the differences *D* vary from – 28% to +11% of the average value for a certain station in June and from – 22% to +25% in July). The value of *D* = (*Т*2010 – *Т*post)/*T*postis 14% in August (for the region) and varies from – 11% to +48% for certain stations.

14 Atmospheric Aerosols – Regional Characteristics – Chemistry and Physics

are presented in Fig. 8.

(1)

(2)

The examples of the long-term time variations for Tand AOD in the differentRussia regions:North,Central part and South of theEuropean Part of the Russia andRussianFar East

**Figure 8.** Examples of the long-term time variations for T(blue)and AOD (green) in the different Russia

The spatial variations in the air turbidity factor according to ground-based measurement data from 18 solar radiometry stations within the territory (40°–70° N, 30°–60° E) in summer 2010. We have shown earlier (Makhotkina et al., 2005; Plakhina et al., 2007, 2009, 2010) that the spatial distribution of the aerosol optical depth (AOD) over the territory of Russia averaged over more than 30 years corresponds to the model of global atmospheric aerosol distribution over Eurasia and the satellite AOD monitoringresults, presented in the 3rd and 4th IPCC reports; it shows a decrease in the aerosol turbidity from southwest to northeast.

**7. Fires above the European Part of Russia (EPR) under conditions of** 

regions: South of theEuropean Part of the Russia (1)and North part (2).

**abnormal summer of 2010** 

**Figure 9.** Layout of 18 actinometric stations on the EPR whose data will be analyzed in this section.

Spatial variations in Тare shown in Fig. 10. To interpolate the data of the stations to the whole region under study , we also used features of the MATLAB package, i.e., the option for creating a homogeneous grid for the EPR region under study, the option of bilinear (horizontal and vertical) interpolation of data from 18 stations to the territory (40°–70° N, 30°–60° E), and the projection of the function Т*=* F(ϕ, λ) (where ϕand λare the longitude and latitude, respectively, for each of the observational points) to the grid. The spatial distribution of the mean Tpost(for June, July, and August) for the "postvolcanic" period corresponds to the results obtained earlier (Plakhina et al., 2009) for the long-term annual average AOD. In this period, Tpostquasi -monotonically decreased from southwest to



Variations in the Aerosol Optical Depth Above the Russia

from the Data Obtained at the Russian Actinometric Network in 1976–2010 Years 17

Thus, we have ascertained the peculiarities of spatial variations in the air turbidity factor in summer 2010 in comparison with the long-term average spatial variations, which have been manifested in both distribution character and the value of the anomalies of the turbidity factor.

**8. Changes in integral and aerosol atmospheric turbidity in Trans-Baikal** 

The turbidity factor T and atmospheric aerosol optical thickness AOD for the wavelength 0.55 μ is used in this section as atmospheric transparency characteristics. The series T and

From Fig. 12, 13 and Table 5 it is evident that AOD and T have the apparent seasonal dependence: maximal values of the aerosol turbidity are observed in spring (mean excess above the year ones is 25%), maximal values of the integral turbidity are observed in summer (mean excess above the year ones is 10%). At the same time the structure of the spatial distribution is similar in April and in July as for AOD so for T. The sources, formed AOD and T spatial distribution: prevailing air circulations, bearing of the aerosol and water vapor rich air masses (and vice versa), "constant" local aerosol sources, antropogenic or

From Fig. 14, 15 it is evident that in July it is exist the constant district in Trans-Baikal region with high AOD (may be the fires); in April a structure of the AOD field is formed by the air masses arriving from the south directions. But in April a structure of the T is not so apparent. In Fig.16 the variation of the month averaged values of FQ - fires quantity (aircraft data) and factor of integral turbidity T are showed. It is observed that FQ have seasonal variations with the maximum value in May, at the same time maximum for T is observed in July. We can also see the growth of T, connected with the El Chichon eruption in 1982 - 1983 years. In Fig.17 the wavelet spectra of the fire quantity ( FQ) and factor of integral turbidity (T) series demonstrate the oscillations by 12 moths period ( in both series) up to 1982-83 years (1982 y. - volcano eruption). Then the oscillations by 6 - 3 month periods are exist in the FQ series, which are connected with the variations of the FQ - fire quantity. Colorbar

In Fig.18 the variation of the month averaged values of fires quantity FQ (aircraft data) and factor of integral turbidity T are showed during 1992 -2009 years. It is also observed that the FQ have seasonal variations with the maximum value in May, at the same time maximum for T is observed in July. We can also see the decrease of T, connected with the Pinatubo eruption during 1992-1993 years. In Fig.19 the wavelet spectra of the fire quantity ( FQ) and factor of integral turbidity (T) series demonstrate the oscillations by 12 moths period ( in both series) from 1997 year up to 2005 year ( in FQ series) and up to 2006 year ( in T series) . Then the oscillations by 7- 3 monhs are exist in the FQ series, which may be also connected with the variations of the fire quantity. Colorbar represents normalized

AOT were analyzed for the 1976–2010 years for the stations presented in Fig.11.

**and Central Siberia** 

natural (for example, the forest or peat fires).

represents normalized variances.

variances.

**Table 4.** Long-term monthly average values of the turbidity factor T (1994-2009 years) and the corresponding values for summer 2010 along with the regional maximum values of mean *T.* The number of daily average values of *T* used in the averaging is mentioned in the parenthesis in the second column.

northeast; the regions of localization of regional tropospheric aerosol sources are invisible (except for Archangelsk). The June–July average values of *Т*at the Archangelsk station have been increased during the "postvolcanic" period: a local (and/or regional) atmospheric aerosol source is traceable; it can be both frequent natural forest fires and anthropogenic industrial factors in this Russian region. The pattern differed significantly before 2010. In June, the spatial variations in Тwere close to distributions of *Т*post with a certain northward shift of the regions of maximum transparency (Т= 2 – 2.5) with a decrease in means for June (Table 2) throughout the region in comparison with the "postvolcanic" period. In July, the monotonicity in a decrease in the turbidity was obviously disturbed in the northeast direction. A south-to-north "tongue" of increased values of the turbidity factor is observed (Т= 3.5 – 4.0). Finally, in August, an epicenter (closed region) of anomalous air turbidity (Т= 4.5 – 5.5) was formed within the region 48°– 55° N and 37°– 42° E, which is located to the south of Moscow and covering the Moscow region by its periphery (Т= 4.0 – 4.5). This pattern resulted from the action of the blocking anticyclone, which prevented air mass ingress from the west, provided for closed air circulation in the EPR, and a favored temperature rise over the EPR and a rapid increase in the forest fire area. Fire aerosols accumulated in the atmosphere through this period. This process was the most pronounced in the 1st decade of August. Our pattern of spatial distribution of *Т*in August 2010, obtained from ground based measurements of the direct solar radiation flux, is in a good agreement with the map of AOD distribution in the EPR (within the region 50°– 65° N, 30°– 55° E) in the 1st decade of August presented in (Sitnov, 2010 ).

Thus, we have ascertained the peculiarities of spatial variations in the air turbidity factor in summer 2010 in comparison with the long-term average spatial variations, which have been manifested in both distribution character and the value of the anomalies of the turbidity factor.

16 Atmospheric Aerosols – Regional Characteristics – Chemistry and Physics

June 3.0

July 3.2

August 3.2

the 1st decade of August presented in (Sitnov, 2010 ).

2.95

3.42

3.73

**Table 4.** Long-term monthly average values of the turbidity factor T (1994-2009 years) and the corresponding values for summer 2010 along with the regional maximum values of mean *T.* The number of daily average values of *T* used in the averaging is mentioned in the parenthesis in the second

northeast; the regions of localization of regional tropospheric aerosol sources are invisible (except for Archangelsk). The June–July average values of *Т*at the Archangelsk station have been increased during the "postvolcanic" period: a local (and/or regional) atmospheric aerosol source is traceable; it can be both frequent natural forest fires and anthropogenic industrial factors in this Russian region. The pattern differed significantly before 2010. In June, the spatial variations in Тwere close to distributions of *Т*post with a certain northward shift of the regions of maximum transparency (Т= 2 – 2.5) with a decrease in means for June (Table 2) throughout the region in comparison with the "postvolcanic" period. In July, the monotonicity in a decrease in the turbidity was obviously disturbed in the northeast direction. A south-to-north "tongue" of increased values of the turbidity factor is observed (Т= 3.5 – 4.0). Finally, in August, an epicenter (closed region) of anomalous air turbidity (Т= 4.5 – 5.5) was formed within the region 48°– 55° N and 37°– 42° E, which is located to the south of Moscow and covering the Moscow region by its periphery (Т= 4.0 – 4.5). This pattern resulted from the action of the blocking anticyclone, which prevented air mass ingress from the west, provided for closed air circulation in the EPR, and a favored temperature rise over the EPR and a rapid increase in the forest fire area. Fire aerosols accumulated in the atmosphere through this period. This process was the most pronounced in the 1st decade of August. Our pattern of spatial distribution of *Т*in August 2010, obtained from ground based measurements of the direct solar radiation flux, is in a good agreement with the map of AOD distribution in the EPR (within the region 50°– 65° N, 30°– 55° E) in

(maximum) <sup>D</sup>

(3.9) 13%

(4.2) 13%

(4.3) 14%

(4) -6% 18%

(4.1) +4% 19%

(5.3) 14% 21%

Standard deviation in the series of monthly average values for different stations

Period Month Mean

June (165)

July (250)

August (125)

1994 – 2009 years

2010 year

column.
