Gennadii N. Tolmachev

Optik-É AN-30 Aircraft Laboratory for Studies of the Atmospheric Composition

AbstractThe scientific instrumental complex of the Optik-E AN-30 aircraft laboratory developed at the Institute of Atmospheric Optics of the Siberian Branch of the Russian Academy of Sciences is described in detail. Specifications of the main units of the instrumental complex are presented. Special attention is given to the metrological support of measurements of the atmospheric parameters. Experimental capabilities of the aircraft laboratory are illustrated by the results obtained in recent flights over various regions of the Russian Federation.

The scale of ozone destruction in clouds

Changes in the concentration of tropospheric ozone in clouds were investigated based on aircraft sensing data. Three ozonometers were used for the measurements—one chemiluminescent 3-02P and two UV 49C (Thermo Environment Inc., United States). The following types of clouds were studied: Cu, Cu med., St, Sc, As, and Ac. The thickness of the cloud layers was 1.5 km on average and varied from 0.4 to 4.5 km. The ozone destruction in clouds was 11–15 ppb on average and ranged from 3 to 34 ppb; it changed nearly twofold depending on the cloud type. The estimation of the annual runoff of ozone in clouds has shown that it is close to the annual ozone balance in the troposphere.

Ozone vertical distribution in the troposphere over south regions of Western Siberia

Dynamics of the tropospheric ozone vertical distribution over one of the Siberian regions is considered based on the data of long-term atmospheric sensing onboard the “Optik-E”. AN-30 aircraft laboratory with the use of a 3-02P chemiluminescence lidar. Two modes are clearly distinguished in the annual variation of ozone vertical distribution: autumn-winter and spring-summer. The change from the autumn-winter mode to the spring-summer one begins near the Earth’s surface in the end of February and ends in the upper troposphere in the end of April; the change back begins in the upper troposphere in the beginning of September and ends in the midtroposphere in the middle of October. Three clearly pronounced maxima and two minima were fixed in the free troposphere during the period under consideration (1997–2009). Not all of them were reflected in the ground layer, as zones of increased ozone concentrations do not reach the upper troposphere. It is most probable that ozone was generated from compounds transported from other regions, due to changes in circulation processes. Peculiarities of ozone distribution in the ground layer are also considered.

Hydrocarbon composition of tropospheric aerosol in the south of Western Siberia

We considered the methodological questions: aerosol sampling on board research aircraft, extraction of an organic component, and identification of its constituent compounds. It is verified how aviation materials (kerosene, oil, hydraulic fluid) can influence the measurement data. We analyzed the composition of organic components of atmospheric aerosol, sampled in the winter-spring period of 2013 at altitudes of 500–7000 m over the southern part of the Novosibirsk reservoir. In the samples, we identified the normal-structure alkanes, cyclanes, and alkyl arenes. Cyclic saturated and alkyl aromatic hydrocarbons were detected in the composition of atmospheric aerosols of Western Siberia for the first time.

Air-Temperature Dependence of the Ozone Generation Rate in the Surface Air Layer

The temperature dependence of the atmospheric ozone generation rate was studied based on measurements in a reference area. The type of this dependence is determined by the method based on the comparison of variations in the ozone concentration when a hot or cold wave passes above the measurement post. This approach allowed us to derive for the first time the quantitative, but not qualitative, dependence type. The coefficients of the expression used depend on both the air temperature and initial ozone concentration. Thus, at the long-term minimum of the surface ozone concentration (1999) at a temperature of 30°C, its increase of 5 μg/m3 corresponded to a temperature change of 1°C. At a maximal concentration (2001) and the same temperature, the increase is almost 25 μg/m3 per 1°C. In the intermediate periods (1997 and 2010), it was about 14 μg/m3 per 1°C. The analysis shows that the quadratic character of the given dependence is conditioned by the nonlinear increase in reaction constants and the quadratic increase in hydrocarbon emissions by vegetation with increasing air temperature.

Vertical Distributions of Gaseous and Aerosol Admixtures in Air over the Russian Arctic

Data on the vertical distribution of gaseous and aerosol composition of air, measured onboard the Tu-134 Optic airborne laboratory in October 2014 over the Kara Sea and coastal areas of the Russian Arctic, are presented. We revealed the specific features of the altitude distributions of CO2 and aerosol over the Kara Sea as compared to continental conditions. No significant deviations from continental distributions are found for CH4, CO, and O3.

Dependence of the surface ozone concentration on the air temperature and conditions of atmospheric circulation in Western Siberia in the warm season (May-September)

The relationship between the surface ozone concentration and the air temperature (O3-T) is rather strong. It is more pronounced for day-to-day variations of O3 and T for every particular month in comparison with year-to-year variations of monthly average values. The O3-T relationship is variable from one year to another. The correlation coefficient can be both positive (achieving about 0.8) and negative. The analysis of some cases revealed that the magnitude of O3-T relationship depends on the character of atmospheric circulation. For the analyzed situations, the O3-Т correlation was stronger at the well-developed advection processes and dynamic alternation of air masses. We have found that the increase of the surface ozone concentration and the air temperature at the measurement site for the cases of threefold and higher excess of the maximum permissible diurnal average ozone concentration (MPCda) occurs synchronously with the alternation of air masses. The analysis of the geopotential height gradient (GHGS) [1] and the corresponding behavior of the potential temperature at the level of dynamic tropopause has demonstrated that, in general, GHGS well reflects the dynamics of air mass alternation, at least, for the most of analyzed cases of heat and cold waves. The use of the rigorous blocking criterions (GHGS>0) yielded no positive results. In addition, no one case of threefold and higher excess of MPCda of ozone was observed for the conditions of “actual” blocking with a duration of five and more days.

Annual dynamics of aerosol organic components in the free atmosphere over South-Western Siberia

We study the annual behavior of the concentration of organic components of the atmospheric aerosol, sampled onboard the Tu-134 Optik airborne laboratory in the atmospheric layer of 500–8500 m. The concentration of the organic component in aerosol composition is found to be maximal during spring and minimal during fall. Compounds ranging from C8H18 to C35H72 are detected in the composition of aerosol particles. The range of hydrocarbons is the widest during the winter period (C12H26–C35H72) and during spring (C8H18–C31H64), and it is markedly narrower during summer (C18H38–C33H68) and during fall (C16H34–C31H64). One mode (n-alkane C20H42) predominates in aerosol composition throughout the year. A secondary maximum, corresponding to n-alkane C29H60, appears during the summer period.

Chemical composition of atmospheric aerosols over background areas of the southern part of Western Siberia observed during the IAO Complex Atmospheric Radiation Experiment carried out in December 2015

The study presents the data on the concentrations of chemical components measured in aerosol samples collected during the IAO complex atmospheric radiation experiment (organized by the V.E. Zuev Institute of Atmospheric Optics) carried out in December 22, 2015. Their vertical distributions derived from the sampling data performed with the use of “Optik” Tupolev-134 aircraft laboratory are reported. Both parts of the experiment were conducted on the same route over background areas of Tomsk and Novosibirsk regions in the daytime. General time duration of the flight was about 3,5 hours. Sampling was carried out on both routes onto Petryanov’s filters AFA-HP-20 in the following troposphere layers 7000-5500, 4000-3000, 2000-1500 and 1000-500 m. The differences in concentrations of carbon-free inorganic ions and chemical elements in the aerosols on the Tomsk and Ordynskiy routes are discussed in the paper. An altitudinal distribution of inorganic ions in both areas is very similar only for one ion - SO4 2-. The top layer is characterized by the smallest differences in the concentrations of the other components under consideration, and even almost complete coincidence of the total concentration of ionic macro components for both sensing areas. The trend in the vertical distribution of elements stored for 2/3 of them like ionic component. As many ionic components in the Tomsk region of sensing we observed inverse nature of the distribution of a large part of the element concentrations in the middle layers.

Complex experiment on the study of microphysical, chemical, and optical properties of aerosol particles and estimation of atmospheric aerosol contribution in the Earth radiation budget

The main aim of the work was complex experimental measurements of microphysical, chemical, and optical parameters of aerosol particles in the surface air layer and free atmosphere. From the measurement data, the entire set of aerosol optical parameters was retrieved, required for radiation calculations. Three measurement runs were carried out in 2013 within the experiment: in spring, when the aerosol generation maximum is observed, in summer (July), when the altitude of the atmospheric boundary layer is the highest, and in the late summer – early autumn, when the second nucleation period is recorded. The following instruments were used in the experiment: diffusion aerosol spectrometers (DAS), GRIMM photoelectric counters, angle-scattering nephelometers, aethalometer, SP-9/6 sun photometer, СЕ 318 Sun-Sky radiometer (AERONET), MS-53 pyrheliometer, MS-802 pyranometer, ASP aureole photometer, SSP scanning photometer, TU-134 Optik flying laboratory, Siberian lidar station, stationary multiwave lidar complex LOZA-M, spectrophotometric complex for measuring total ozone and NO2, multivariable instrument for measuring atmospheric parameters, METEO-2 USM, 2.4 AEHP-2.4m station for satellite data receive. Results of numerical calculations of solar down-fluxes on the Earth’s surface were compared with the values measured in clear air in the summer periods in 2010—2012 in a background region of Siberian boreal zone. It was shown that the relative differences between model and experimental values of direct and total radiation do not exceed 1% and 3%, respectively, with accounting for instrumental errors and measurement error of atmospheric parameters. Thus, independent data on optical, meteorological, and microphysical atmospheric parameters allow mutual intercalibration and supplement and, hence, provide for qualitatively new data, which can explain physical nature of processes that form the vertical structure of the aerosol filed.