No abstract

Abstract. The change of the global climate is most pronounced in the Arctic, where the air temperature increases 2 to 3 times faster than the global average. This process is associated with an increase in the concentration of greenhouse gases in the atmosphere. There are publications predicting the sharp increase in methane emissions into the atmosphere due to permafrost thawing. Therefore, it is important to study how the air composition in the Arctic changes in the changing climate. In the Russian sector of the Arctic, the air composition was measured only in the surface atmospheric layer at the coastal stations or earlier at the drifting stations. Vertical distributions of gas constituents of the atmosphere and aerosol were determined only in a few small regions. That is why the integrated experiment was carried out to measure the composition of the troposphere in the entire Russian sector of the Arctic from on board the Optik Tu-134 aircraft laboratory in the period of ​​​​​​​4 to 17 September of 2020. The aircraft laboratory was equipped with contact and remote measurement facilities. The contact facilities were capable of measuring the concentrations of CO2, CH4, O3, CO, NOx​​​​​​​, and SO2, as well as the disperse composition of particles in the size range from 3 nm to 32 µm, black carbon, and organic and inorganic components of atmospheric aerosol. The remote facilities were operated to measure the water transparency in the upper layer of the ocean, the chlorophyll content in water, and spectral characteristics of the underlying surface. The measured data have shown that the ocean continues absorbing CO2. This process is most intense over the Barents and Kara seas. The recorded methane concentration was increased over all the Arctic seas, reaching 2090 ppb in the near-water layer over the Kara Sea. The contents of other gas components and black carbon were close to the background level. In bioaerosol, bacteria predominated among the identified microorganisms. In most samples, they were represented by coccal forms, less often spore-forming and non-spore-bearing rod-shaped bacteria. No dependence of the representation of various bacterial genera on the height and the sampling site was revealed. The most turbid during the experiment was the upper layer of the Chukchi and Bering seas. The Barents Sea turned out to be the most transparent. The differences in extinction varied by more than a factor of 1.5. In all measurements, except for the Barents Sea, the tendency of an increase in chlorophyll fluorescence in more transparent waters was observed.

Abstract. The article describes a scanning polarization lidar LOSA-M3, developed at the Institute of Atmospheric Optics, the Siberian Branch of Russian Academy of Sciences (IAO SB RAS). The first results of studying the crystalline particles orientation by means of this lidar are presented herein. The main features of LOSA-M3 lidar are the following: 1) an automatic scanning device, which allows to change the sounding direction in the upper hemisphere at the speed up to 1.5 degrees per second with the accuracy of angle measurement setting at least 1 arc minute; 2) separation of polarization components of the received radiation is carried out directly behind the receiving telescope, without installing the elements distorting polarization, such as dichroic mirrors and beamsplitters; and 3) continuous alternation of the initial polarization state (linear - circular) from pulse to pulse that makes it possible to evaluate some elements of the scattering matrix. Several series of measurements of the ice cloud structure of the upper layers in the zenith scan mode were carried out in Tomsk in April-October 2018. The results show that the degree of horizontal orientation of particles can vary significantly in different parts of the cloud. The dependence of signal intensity on the tilt angle reflects the distribution of particle deflection relative to the horizontal plane, and is well described by the exponential dependence. The values of cross-polarized component in most cases show a weak decline of intensity with the angle. However, these variations are smaller than the measurement errors. We can conclude that it is practically independent of the tilt angle. In most cases the scattering intensity at the wavelength of 532 nm has a wider distribution than at 1064 nm.

No abstract

The paper presents the results of lidar observations of the atmosphere over the water area of Lake Baikal. Integrated shipboard research using the research vessel «Academician V.A. Koptyug», are held annually, using the LOSA-A2 lidar, as well as local means (gas analyzers). Additionally, satellite data and information about the meteorological parameters of the atmosphere during the experiments are involved. The route of the ship goes all over the lake. An analysis is being carried out to identify the main sources of air pollution in the Baikal region.