Assessment of the influence of air invasions from the upper troposphere on the CO total column amount in the St. Petersburg region

The influence of air invasions from the upper troposphere on the CO total column amount is studied on the basis of spectroscopic measurements of the CO total column amount, backward trajectories of air-mass motions (the HYSPLIT model), and meteorological data. It is shown that the observed invasions of substratospheric and upper-troposphere air masses determine the minimum CO total column amount in late January-late March. The invasion of air masses from the upper troposphere can result in a decrease in the CO total column amount to 30% (of its mean values). Using January 31, 2000, as an example, we show the influence of the invasion of Arctic air masses from the upper troposphere on the CO total column amount in the St. Petersburg region: the results of measurements of the CO total column amount in the St. Petersburg region and at the Kiruna polar station (NDACC) are in agreement to within 1% if the vertical transport of air masses is taken into account. Thus, for a correct combined analysis of measurement data on the CO total column amount for different observation stations, it is necessary to use data on air-mass trajectories.     

Determining Both Tropospheric and Stratospheric СО2 Contents Using a Ground-Based IR Spectroscopic Method

Izvestiya, Atmospheric and Oceanic Physics - Results obtained from ground-based high spectral resolution measurements of solar IR radiation absorption spectra are analyzed. These measurements have...     

Stratospheric NO2 content according to data from ground-based measurements of solar IR radiation

Atmospheric NO₂ content data obtained from regular ground-based measurements of solar IR radiation in the St. Petersburg region using a spectrometer with a high spectral resolution are analyzed. The absorption spectra of the NO₂ multiplet in the vicinity of ～2915 cm^?1 allow one to obtain data on variations in the stratospheric total content of NO₂ in 2009–2011. The accuracy of these data is estimated from their comparison with data obtained from independent ground-based and satellite measurements. The parameters of the seasonal cycle of the stratospheric content of NO₂ are estimated. The body of data accumulated during these measurements in the IR region made it possible to isolate the component of a daytime photochemical increase in the stratospheric content of NO₂ and estimate its rate.     

Study of the factors determining anomalous variability of carbon dioxide total column amount over St. Petersburg

Results of spectroscopic measurements of the carbon dioxide total column amount near St. Petersburg during forest fires in the period from August to September 2002 are analyzed. The HYSPLIT model is used to calculate air-mass trajectories and CO distribution on a mesoscale in this period. The HYSPLIT model simulations and measurements of carbon dioxide total column amount yield an estimate of the specific intensity of CO emission in a Pskov forest fire on August 28–September 8, 2002, equal to 0.17–0.26 kg m². This estimate can be used for an estimation of the integral CO emission from fires in northwestern Russian forests and for model simulations of atmospheric CO concentration fields. The estimate of the CO emission from forest fires that is obtained from ground-based measurements can also be made on the basis of satellite measurements if they contain information on CO in the lower tropospheric layers (0 to 2 km).     

Detection of Large Fluctuations in Ozone Content in the Middle Atmosphere during Sudden Stratospheric Warmings and Subpolar Latitudes of the Arctic

Geomagnetism and Aeronomy - The results of microwave radiometry studies of the ozone-content dynamics in the middle atmosphere above Peterhof during stratospheric warmings of two winters,...     

Time variability of the total methane content in the atmosphere over the vicinity of St. Petersburg

The results of measuring the methane content in the entire atmospheric thickness over the St. Petersburg region are given for 1991–2007. It is shown that, within this period, the mean annual cycle of the total methane content is characterized by its maximum values in December–January and its minimum values in June–August when the annual-cycle amplitude amounts to ∼3.6%. In this case, the annual variations in the total methane content may differ significantly from the mean annual cycle obtained in some years. A statistically significant linear trend of the total CH₄ content has not been revealed for 1991–2007. The obtained values of the linear-trend index have opposite signs in the winter and summer months (positive for January 0.6 ± 0.2%/year and February 0.4 ± 0.2%/year and negative for July 0.3 ± 0.2%/year and August 0.2 ± 0.1%/year). This fact suggests the tendency for an increase in the amplitude of the annual cycle of the total CH₄ content. The results of a spectral analysis of a series of data on the total CH₄ content show that, for 1991–2007, the following harmonics are pronounced with a confidence of 95%: 12 months (annual harmonic), 32 months (quasi-biennial oscillations), and 55 months (4.5 years), which are also pronounced in the series of meteorological parameters and total ozone content.     

Seasonal variations in the total content of hydrogen fluoride in the atmosphere

The results of ground-based measurements of the total content (TC) of hydrogen fluoride in the atmosphere in Peterhof near St. Petersburg for one year (from April 2009 through April 2010) using a Bruker IFS125 Fourier spectrometer with a high spectral resolution (0.005 cm^?1) are presented. The well-known computer code SFIT2 (Zephyr-2) was used for the radiation data inversion. Random measurement errors were 1–5% and the systematic error was 5–10%. The seasonal trend of the HF TC in Peterhof is characterized by a minimum in summer and a maximum in winter through early spring and is very close to the seasonal HF TC trend obtained at the Harestua Network for the Detection of Atmospheric Composition Change (NDACC) station located at about the same latitude. A comparison of the St. Petersburg State University (SPbSU) ground-based measurements with the data of satellite HF TC measurements (with an ACE-FTS instrument) showed a good quantitative agreement of the results for the entire period of observations. According to our ground-based measurements and the satellite measurements with the ACE-FTS instrument, the mean values of the HF TC and its rms variations during the period under investigation are 1.77 × 10¹⁵ and 1.80 × 10¹⁵ cm^?2 (difference 1.5%) and 21 and 18%, respectively.     

Ground-based spectroscopic measurements of the total nitric acid content in the atmosphere

The results of the first ground-based spectroscopic measurements in Russia of the total content (TC) of nitric acid in the atmosphere near St. Petersburg over the period April 2009–October 2011 are presented. These measurements show a substantial seasonal trend of the HNO₃ TC with maximal values in the winter period and early in the spring and minimal values in the summer time. The seasonal trends and variations in the daily mean values of HNO₃ TC near St. Petersburg in the winter and spring periods agree well with observations at the Kiruna station of the international NDACC network.     

Estimation of Nocturnal Area Fluxes of Carbon Cycle Gases in Saint Petersburg Suburbs

Carbon dioxide, methane, and carbon monoxide are the carbon cycle gases, the data on their emissions are needed when monitoring air pollution and developing methods for reducing anthropogenic emissions to the atmosphere and for climate forecasting. The estimates of nocturnal area fluxes for CO₂, CH₄, and CO presented for a suburb of Saint Petersburg (Peterhof) are obtained using the box model and continuous observations of concentration of these gases. The mean values of CH₄, CO₂, and CO fluxes estimated for Peterhof for 2014–2015 are 44 ± 27, 6100 ± 4000, and 90 ± 100 t/(km² year), respectively. The intensity of the CO area flux has pronounced seasonal variations characterized by the maximum of ~(160 ± 120) t/(km² year) in November—February and by the minimum of ~(30 ± 20) t/(km² year) in June-July. The analysis of the ratio of CO/CO₂ fluxes identified the main types of anthropogenic sources typical of Peterhof: motor transport, natural gas combustion, and the use of wood stoves for the heating of private low-rise buildings (in the cold season).