Home – Home – Jornals – Atmospheric and Oceanic Optics 2017 number 6

Trends of CO and CH₄ total column (TC) are estimated from AIRS spectrometer data for the "Eurasia" domain (0-180° E, 0-85° N) for different time periods and seasons. The results are compared with similar estimates obtained from ground-based spectroscopic measurements at IAP RAS stations (ZSS, Zotto, and Beijing), st. Peterhof of St. Petersburg State University, and NDACC stations located in the test domain. According to the findings, the CO TC over Northern Eurasia generally decreased during the period 2003-2015 with a rate of 0.05-1.5%/year depending on the region, while the CH₄ TC increased at a rate of 0.16-0.65%/year. After 2007, there is a trend toward an increase in CO TC in the summer and autumn months in most of mid- and high-latitude Eurasia background areas, as well as an increase in CH₄ TC growth rate. Positive trends in CO cannot be explained by the growth of emissions from fires or anthropogenic emissions. Thus, one of possible causes may be changes in the entire global photochemical system occurring against the backdrop of global climate change, in particular, changes in the "sources/sinks" ratio for small atmospheric components.

A microphysical model of photophoretic motion of soot aggregates is presented, which takes into account their fractal structure. Comparison with known experimental data is executed, and good qualitative and quantitative agreements are shown. Characteristics of photophoretic motion of fractal-like soot aggregates in the field of atmospheric radiation are calculated. For the model of fractal-like particles, the photophoretic effects with soot aerosol in the stationary atmosphere are the most pronounced in the upper troposphere - middle stratosphere.

A “paraffin” hypothesis of the origin of spring nucleation bursts (NB) is discussed. The organic part of atmospheric aerosol is analyzed using the gas chromatography-mass spectrometry and the chemical structure classification. The results obtained during NB events and in preceding (next) days (when no new particle formation was observed) are compared. A suggestion that new particles are formed from the surface waxes of plants during the NB events is considered.

Model estimates of air black carbon (BC) concentrations at different sites of the Russian North were made for 2000-2013. Different physical sources of BC emissions (anthropogenic and from wildfires), their intensities (from different databases), and their contributions to BC air concentrations in the Arctic are discussed for winter and summer. We used GFED, MACCity, and other satellite data, as well as the ground-based data of Russian official statistics on pollution emissions to the atmosphere. Long-range atmospheric transport of BC was modeled by analysing back-trajectory statistics from ARL NOAA (HYSPLIT model). In total, anthropogenic BC inputs exceed wildfire ones in surface air BC concentrations even in summer when contributions from distant anthropogenic sources are minimal. Annual and interannual variations in BC air concentrations are sizable. Variations in air BC concentration along the Russian Arctic coast may be above two orders with maximal values near Nenetsky Nature Reserve (near the Pechora River delta). There are open flares of oil/gas mining companies with extreme BC emissions in close proximity to this site. So, the results measured at one point and/or during a season or even a year should not be the basis for long-term conclusions and forecasts in relation to the entire region.

The kinetics of furfural photolysis in air and nitrogen at different water vapor concentrations is studied. The photolysis rate constants of furfural are shown to be the same in air and in nitrogen. An increase in the water vapor concentration from 0 to 18 Torr results in an increase in the photolysis rate by a factor of 1.5. It has been experimentally shown that the yield of aerosol products for С₅Н₄О₂ photolysis in air is independent of [Н₂O] and equals to 1.8 ± 0.2%, while the yield increases from 1 to 2% during the photolysis in nitrogen as [Н₂O] increases from 0 to 18 Torr. HCO and furil radicals formed during С₅Н₄О₂ photolysis have been detected and identified using the spin-trapping technique; this proves the radical mechanism of С₅Н₄О₂ photolysis. The partial analysis of aerosol products is performed. It is shown that aerosol particles consist of a complex mixture of oxidative ring cleavage compounds and a small amount of products containing furan ring. Based on the experimental data, a qualitative scheme of the chemical processes describing the formation of gaseous and aerosol products during furfural photolysis is suggested.

The air composition of Moscow is studied for the conditions of joint smoke screening by near forest fires in Moscow region and far forest fires in October 2014. According to ecological monitoring data the ratio of nitrogen oxides and carbon monoxide mass concentrations attained 0.35 in “fresh” smokes of near fires and reduced to 0.025 in “old” smokes of far fires. The ratio of nitrogen oxide mass concentration to the sum of nitrogen oxide and dioxide concentrations attained 0.87 in “fresh” smokes and reduced to zero in “old” smokes. It is shown that statistical parameters and empirical probability distributions of carbon monoxide and nitrogen oxide in smoky atmosphere of Moscow in October 2014 are distinguished radically from the corresponding characteristics in clear atmosphere and during smoke screenings of 2002 and 2014. Two-segment approximations by exponential functions for carbon monoxide concentration empirical distribution and by power functions for nitrogen monoxide concentration empirical distribution are used. The carbon monoxide and nitrogen oxides concentrations strongly spectrally correlated in a wide range of frequencies in smoky air of Moscow in October 2014. This indicates simultaneous generation of the above impurities during forest fires. The spectral correlation coefficient of nitrogen dioxide and ozone varied from +1 to -1 on different time scales, which witnesses complex relationships between ozone and nitrogen oxides in smoky atmosphere.

Routine measurements of atmospheric aerosol optical depth (AOD) were carried out in 2006-2013 in Sevastopol within the AERONET (http://aeronet.gsfc.nasa.gov) program using a CE 318 sun photometer. In the end of 2015, owing to the cooperation between V.E. Zuev Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences, and Marine Hydrophysical Institute, Russian Academy of Sciences, the observations were resumed with a SPM portable photometer operating in the spectral range 0.34-2.14 mm. The results of AOD measurements in Sevastopol, at the “Sea Hydrophysical Polygon” oceanographic platform (Katsiveli), and in expeditions on “Professor Vodyanitsky” research vessel are presented. The average AOD measured in the Black Sea region in different months are compared with long-term data in Sevastopol. Situations with high aerosol opacity and the effect of air mass transfer directions on the AOD, including fine and coarse modes, are analyzed.

The results of the measurements of black carbon and fine aerosol content in Beijing and in the background region 50 km north-east of the capital of China are analyzed. The measurements were carried out for many years, mainly in the autumn. A reduction in the concentration of black carbon, having regional character, has been revealed. An earlier conclusion about the reduction, on average, of the relative contribution of soot aerosol with the growth of air the turbidity has been confirmed.

The possibilities of modern foreign and domestic ground-based microwave radiometric systems of measuring structural atmospheric parameters (temperature profiles, water vapor, and liquid water) are analized. Data of Russian microwave temperature profilers MTP-5 are used in the study of the urban heat island vertical structure, for improvement of the forecast of adverse meteorological phenomena, and monitoring of thermal stratification of the atmospheric boundary layer in polar regions and during solar eclipses. Some results of cloud parameters monitoring with the use of multi-channel microwave radiometric complex “Microradcom” are presented.

We discuss the development of a modeling system for the study of climatic and environmental problems in urban areas exposed to natural and anthropogenic impacts. Some typical tasks are considered: formation of mesoclimates and air quality of urban agglomerations against the background of global processes in specific regions. The models of hydrodynamics, transport, and transformation of various substances in the gas and aerosol states are used for solving direct and inverse problems of this class. The modeling technology is based on variational principles and the concept of adjoint integrating factors. This provides a consistent unification of all the models, the construction of numerical schemes, and assimilation of operational data from various monitoring tools. We propose a new algorithm for the implementation of the model for parameterization of the vertical turbulent exchange in the arbitrary stratified atmosphere. The results of the scenarios of the formation of the typical mesoclimates and distribution of impurities in the atmosphere of Novosibirsk agglomeration are presented.

Data on the surface ozone concentrations measured at six coastal stations in Bulgaria, Greece, Montenegro, and Russia are compared. Seasonal and diurnal ozone cycles are analyzed for each station. It is shown that differences in ozone regimes are connected with microclimatic and topographic features of the stations, distance from the sea, and level of anthropogenic pollution. High ozone episodes are considered. It is shown that the large-scale ozone episode in the late summer of 2011 was a result of the prolonged abnormal weather, and high ozone concentrations (160-200 μg × m^-3) were formed in plumes of ozone precursors arrived from territories of Caspian gas and oil developments.

The combined effect of orography and temperature stratification on the dispersion of pollutants in an urban heat island is simulated on the basis of three-parametric E - ε - <θ²> (Т-RANS) approach to thermally penetrating convection above the heat island. Two models of the concentration turbulent flow are used for the dispersion of a tracer from a surface source into a stably stratified atmosphere <u_ic > i.e., the implicit algebraic model and calculation from a prognostic equation. The correlation <cθ> between the concentration and temperature fluctuations is found from the solution of a prognostic equation in the both models. The algebraic model minimizes the difficulties in the simulation of turbulent transfer in a stably stratified atmosphere and provides for the results with acceptable accuracy as compared to the complete prognostic model of the concentration turbulent flow.

The variability of the Laptev Sea hydrodynamics is analyzed on the basis of the Arctic Ocean model developed in ICMMG SB RAS. Based on the numerical simulation, we explore possible reasons for the increase in the bottom layer temperature known from observations, including: a) redistribution of water masses over the shelf zone forced by atmospheric dynamics; b) Laptev sea on-shelf inflow of warm and saline waters of Atlantic Layer of the Arctic Ocean, and c) the redistribution of water mass temperature anomalies caused by the heat river flux. The effect of the increase in the bottom layer temperature of the coastal region on the enhancement of underwater permafrost degradation is studied. The upper boundary of the permafrost depth and the permafrost thawing rate are estimated for the modern climate conditions and under the forecasted Arctic climate changes in the 21st century.

The adsorption and photosorption properties of microparticles of Mg(OH)₂ and Ca(OH)₂ in ambient air are studied. The composition of adsorption layer of microparticles is analyzed. The kinetics of photodesorption of molecules from the microparticle surfaces and interaction of Freon 22 (CHF₂Cl) with its surfaces in the dark and under illumination are studied. The effect of weakly-bound CO displacement from the microparticle surfaces is revealed during the Freon 22 dark adsorption. It is suggested that the adsorbed CO is formed in the result of atmospheric CO₂ reduction after the break of Mg-OH bonds. Calcium hydroxide CO is generated during interaction of calcium hydroxide with carbon dioxide on the microparticle surfaces in the presence of water.