Abstract. The primary objective of this complex aerosol experiment was the measurement of microphysical, chemical, and optical properties of aerosol particles in the surface air layer and free atmosphere. The measurement data were used to retrieve the whole set of aerosol optical parameters, necessary for radiation calculations. Three measurement cycles were performed within the experiment during 2013: in spring, when the aerosol generation is maximal; in summer (July), when atmospheric boundary layer altitude and, hence, mixing layer altitude are maximal; and in late summer/early autumn, during the period of nucleation of secondary particles. Thus, independently obtained data on the optical, meteorological, and microphysical parameters of the atmosphere allow intercalibration and inter-complement of the data and thereby provide for qualitatively new information which explains the physical nature of the processes that form the vertical structure of the aerosol field.

The results of sensing of the gas and aerosol composition of the atmosphere with the Optik Tu‐134 aircraft laboratory in the period from 31 July to 1 August 2012 are presented. The measurements were conducted along the flight route Novosibirsk‐Tomsk‐Mirny‐Yakutsk‐Bratsk‐Novosibirsk. A significant part of the Siberian territory during this period was covered by numerous forest fires. The synoptic situation during the measurements was characterized by the presence of low‐gradient field. This fact determined the low rate of transport and diffusion of pollutants and their accumulation in the region under study. The maximal concentrations of CO2, CH4, and CO over fire zones achieved 432 ppm, 2367 ppb, and 4036 ppb, respectively. The aerosol particle number density in emission plumes achieved 4400 cm−3. Outside emission plumes, the concentration ranged within 400–1000 cm−3 depending on the region. The mass concentration of aerosol in plumes increased approximately 7 times (6.9). The enrichment of the concentration of some elements and ions in the plume with respect to the background varied from 1.3 to 9.1 times. The generation of ozone from biomass burning products was observed at plume boundaries. Two versions of this process are possible: ozone generation under and above the plume.

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551.55To verify the hypothesis of closed air circulation on the perimeter of Lake Baikal, airborne and ground-based expeditions were organized. As a result of these expeditions, the occurrence of the air circulation was confirmed and its properties and spatiotemporal characteristics were determined In addition, the role of the circulation in the transport of chemical elements on the lake perimeter is shown.The present paper is aimed at the study of the peculiarities in the spread of chemical elements over the water area of Lake Baikal. It was initiated by the phenomenon of air circulation on the lake perimeter revealed in the course of airborne atmospheric sensing in 1991. Near the western coast of the lake, it has predominantly the northeast direction, and along the eastern coast -the southwest direction. Thus, above the water area there are two circulation branches, each about 600 km long, which move in the opposite directions in different parts of the lake [1, 2]. In our opinion, this phenomenon explains the occurrence of the aerosol, whose chemical composition is close to that of the lrkutsk industrial center, above the entire water area of the lake.Airborne sensing was repeated in June 1995, when the aircraft flew twice around the lake perimeter at altitudes of 400 and 700 m above the water surface, respectively. To analyze the synoptic situation during the experiment, AT850 and AT700 absolute topography maps were used. It turned out that the wind speeds and directions at the examined altitudes depended on the general situation. So, the strengthening of wind on the eastern coast on June 9, 1995 was explained by the occurrence of the forefront of the high-level trough, for which the direction of air-mass transport coincided with the direction of air motion in this branch. Weakening of the wind on the western coast of the lake was caused by the fact that the air-mass transport in the trough was opposite to the direction of air motion in the western branch of the circulation. During the second flight on June 14, 1995, the occurrence of the west-east transport with a velocity of 7 m/s provided practically identical wind speeds on the perimeter of the lake.To analyze the chemical composition of the aerosol, atmospheric air was pumped through the AFA-VP-20 filters. The volume of pumped air was 3--6 m 3 [3]. To analyze the insoluble aerosol fraction, atomic emission spectroscopy was used. Data on the threshold and error of the method are given in [1]. The aerosol was analyzed for Na +, K +, Ca 2+, and Mg -~+ ions by the method of nuclear absorption, and for CI-, NO 3-, and SO42-ions -by high performance liquid chromatography. The characteristics of the methods were described in [4].Samples were taken from 12 test sites, into which the perimeter of Lake Baikal was subdivided (see Fig. 1). Such division was dictated, on the one hand, by the procedure of sampling on the filters in the course of airborne sensing, and on the other hand, by the distribution of possible aerosol sources, which was taken into account. Mass ...