Boris D. Belan

The YAK-AEROSIB transcontinental aircraft campaigns: new insights on the transport of CO2, CO and O3 across Siberia

Two airborne campaigns were carried out to measure the tropospheric concentrations and variability of CO2, CO and O3 over Siberia. In order to quantify the influence of remote and regional natural and anthropogenic sources, we analysed a total of 52 vertical profiles of these species collected in April and September 2006, every ∼200 km and up to 7 km altitude. CO2 and CO concentrations were high in April 2006 (respectively 385–390 ppm CO2 and 160–200 ppb CO) compared to background values. CO concentrations up to 220 ppb were recorded above 3.5 km over eastern Siberia, with enhancements in 500–1000 m thick layers. The presence of CO enriched air masses resulted from a quick frontal uplift of a polluted air mass exposed to northern China anthropogenic emissions and to fire emissions in northern Mongolia. A dominant Asian origin for CO above 4 km (71.0%) contrasted with a dominant European origin below this altitude (70.9%) was deduced both from a transport model analysis, and from the contrasted ΔCO/ΔCO2 ratio vertical distribution. In September 2006, a significant O3 depletion (∼ –30 ppb) was repeatedly observed in the boundary layer, as diagnosed from virtual potential temperature profiles and CO2 gradients, compared to the free troposphere aloft, suggestive of a strong O3 deposition over Siberian forests.

New Insights on the Chemical Composition of the Siberian Air Shed From The Yak-Aerosib Aircraft Campaigns

There are very few large-scale observations of the chemical composition of the Siberian airshed. The Airborne Extensive Regional Observations in Siberia (YAKAEROSIB) French–Russian research program aims to fill this gap by collecting repeated aircraft high-precision measurements of the vertical distribution of CO2, CO, O3, and aerosol size distribution in the Siberian troposphere on a transect of 4,000 km during campaigns lasting approximately one week. This manuscript gives an overview of the results from five campaigns executed in April 2006, September 2006, August 2007, and early and late July 2008. The dense set of CO2 vertical profiles, consisting of some 50 profiles in each campaign, is shown to constrain large-scale models of CO2 synoptic transport, in particular frontal transport processes. The observed seasonal cycle of CO2 in altitude reduces uncertainty on the seasonal covariance between vegetation fluxes and vertical mixing, known as the “seasonal rectifier effect.” Regarding carbon dioxide, w...

Joint radiosonde and doppler lidar measurements of wind in the atmospheric boundary layer

Results of joint measurements of height profiles of wind velocity and direction by the Stream Line pulse coherent Doppler lidar and RS92-SGP radiosonde in Tomsk from 23 to 27 of September, 2013, are presented. It has been established that wind profiles can be retrieved up to heights from 400 to 1100 m depending on the aerosol concentration in the atmospheric boundary layer from lidar data measured at an elevation angle of 45°. It is shown that the coefficient of correlation between lidar and radiosonde measurements of wind velocity and direction is equal to 0.97. The mathematical expectation and standard deviation of the difference between estimates for the wind velocity and direction from the radiosonde and lidar data amount to 0.1 and 0.7 m/s, respectively, for the velocity and 0.8° and 4°, respectively, for the wind direction.

Vertical distribution of greenhouse gases above Western Siberia by the long-term measurement data

By the results of long-term (1997–2007) airborne sounding, the vertical distribution of three greenhouse gases such as CO2, CH4, and N2O above the south of Western Siberia is investigated. The average monthly profiles of the distribution of these components in height and the long-term change in gas concentration at different heights are presented. The climatic characteristics of the vertical distribution of these gases are determined.

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.

Spatial and temporal variability of CO2 and CH4 concentrations in the surface atmospheric layer over West Siberia

The diurnal and annual variation of the CO2 and CH4 concentrations and their spatial distribution over a network of sites developed over the territory of West Siberia are investigated. The CO2 concentration gradient between the northern and southern regions of the territory is retained during the entire year. The diurnal behavior of the methane concentration remains neutral for much of the year, so that it is only at the end of the springtime and at the beginning of the summer that it exhibits a significant amplitude. The annual variation of CO2 has a maximum in the month of December, the concentration starts to decrease in March, and reaches a minimum in July in August. In the central region of the territory, the annual variation of methane has two maxima (in July and in December and January); the greatest interyear methane concentration variability is recorded during the periods of the basic and secondary maxima.

Variability of the content of live microorganisms in the atmospheric aerosol in southern regions of western Siberia.

The results of preliminary studies on the biological component of atmospheric aerosol and annual dynamics of the total atmospheric aerosol protein concentration in the southern regions of Western Siberia were considered in the preceding works [1, 2]. Live microorganisms contained in atmospheric aerosols can be transferred over large distances and to high altitudes without loss of viability [3–7]. Therefore, the properties of the biological component of atmospheric aerosols and sources of their origin should be studied not only near the ground, but also at high altitudes. In this work, we describe the results of measurements of the concentrations of live microorganisms and the compositions of atmospheric aerosols above large forests in the southern regions of Western Siberia.

First results of ground-based Fourier Transform Infrared measurements of the H2O total column in the atmosphere over West Siberia

The first results of the water vapour total column (WVTC) Fourier Transform Infrared (FTIR) measurements carried out over West Siberia (near Tomsk) in the framework of the combined experiment (22 May 2012) are presented. Direct solar radiation spectra with high spectral resolution were recorded by ground-based FTIR spectrometer Bruker IFS-125M. New spectral intervals (the advantage of this spectral band is that observations could be performed without cooling the interferometer’s detector) were tested and then used to retrieve the H2O total columns in the atmosphere by SFIT2 v3.92. Ground-based measurements of the WVTC and aerosol optical thickness in the atmosphere were carried out by means of the automated sun photometers (SP series). Sun photometer and FTIR observations were performed under clear-sky conditions. During this study, we compared data obtained from ground-based remote sensing systems to the results of infrared atmospheric sounding interferometer (IASI) MetOP-A satellite measurements and airborne measurements with the use of the Tu-134 aircraft laboratory. Comparison shows that FTIR observations could give reasonable agreements with sun photometer data within 1%. This value is less than the combined error (1.2%) of both techniques. The average values of total H2O obtained for three measurement systems were as follows: 1.50 and 1.49 g cm–2 for the Fourier spectrometer and sun photometer, respectively, and 1.84 g cm–2 for IASI.

Tropospheric ozone over Siberia in spring 2010: remote influences and stratospheric intrusion

We have identified and characterised different factors influencing the tropospheric ozone over Siberia during spring 2010. This was done by analysing in-situ measurements of ozone, carbon dioxide, carbon monoxide, and methane mixing ratios measured by continuous analysers during an intensive airborne measurement campaign of the YAK-AEROSIB project, carried out between 15 and 18 April 2010. The analysis and interpretation of the observations, spanning 3000 km and stretching from 800 to 6700 m above ground level, were enhanced using the Lagrangian model FLEXPART to simulate backward air mass transport. The analysis of trace gas variability and simulated origin of air masses showed that plumes coming from east and west of the west Siberian plain and from north-eastern China related to biomass burning and anthropogenic activity had enhanced ozone mixing ratios during transport. In one case, low ozone mixing ratios were observed over a large region in the upper troposphere above 5500 m. The air mass was transported from the marine boundary layer over the Norwegian Sea where O3 background concentrations are low in the spring. The transport was coherent over thousands of kilometres, with no significant mixing with mid–upper troposphere air masses rich in O3. Finally, the stratospheric source of ozone to the troposphere was observed directly in a well-defined stratospheric intrusion. Analysis of this event suggests an input of 2.56±0.29×107 kg of ozone associated with a regional downward flux of 9.75±2.9×1010 molecules cm−2 s−1, smaller than hemispheric climatology.

The Blocking Role of the Ural Mountains in the Transborder Transfer of Impurities from Europe to Asia

Distribution of impurities over the region abutting the Ural Mountains is analyzed with the purpose of searching for traces of western European emissions over the territory of Siberia. It is shown that transborder transfer of impurities from Europe to Asia along direct trajectories (along a circle of latitude) from west to east is possible only in the free troposphere, in a layer higher than 2 km. Within the limits of the atmospheric boundary layer, the transfer of impurities from Europe to Siberia is probable only along trajectories rounding the Urals from north or south.