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.     

NO<Subscript>2</Subscript> content variations near St. Petersburg as inferred from ground-based and satellite measurements of scattered solar radiation

An automatic spectral complex developed at the Institute of Physics, St. Petersburg State University, is described. This complex is used for regular ground-based spectroscopic measurements of the total NO₂ content in the vertical column of the atmosphere during the twilight and daylight hours of the day near St. Petersburg (Petrodvorets). In 2004–2006, a number of ground-based twilight measurements of the total NO₂ content were obtained near St. Petersburg, and variations in the NO₂ content in the troposphere were estimated from the results of daytime ground-based measurements. An example of the spatial annual mean distribution of the NO₂ content (central and northern Europe, northwestern Russia) based on the data of satellite measurements over the period 2003–2005 is presented. This example demonstrates the main sources of anthropogenic pollution. An increase in the mean annual contents of tropospheric NO₂ near Moscow and St. Petersburg is preliminarily estimated for the entire period of satellite observations with the GOME instrument at about 30–40% over ten years.     

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.     

Integral emission of nitrogen oxides from the territory of St. Petersburg based on the data of mobile measurements and numerical simulation results

The results of spectroscopic measurements of tropospheric NO₂ content performed on a closed route along the circular road around the city of St. Petersburg in 2012, 2014, and 2015 are presented. A procedure for determining the integral emission of NO _x based on the data of measurements on the route enveloping the sources under study is described. An analysis of the experimental data together with the results of a numerical simulation of air pollutant dispersion (the HYSPLIT model) provided an estimate of the total volume of NO _x emitted by all sources located inside the circular road. The average emission rate of NO _x according to the sources of the megacity of St. Petersburg is 57000 t/yr, which correlates satisfactorily with the official data of a municipal inventory of the sources of air pollution (62000–63 000 t/yr).     

Some features of seasonal variations in the methane content in the atmosphere over northern Eurasia

The climatic trends and basic features of seasonal variations in and anomalies of the concentration of methane in the atmospheric surface layer are considered on the basis of the current notion of the processes that form the global field of methane in the Earth’s atmosphere. Measurement data on the surface concentration of methane, which were obtained in Moscow and at a number of observation stations in Europe and Siberia in the fall-winter period of the first decade of the 21st century, have been analyzed. It is shown that, in the anomalously warm winter months of 2006/2007, the concentration of methane in the atmosphere over Moscow was higher than in the previous and following years. The excess concentration of methane amounted to 10% in March 2007, which is higher than the mean range of seasonal variations in the monthly mean concentration of surface methane. A comparison between the data obtained in Moscow and the data obtained at three stations of the NOAA global monitoring network and at three Russian Hydrometeorological Research Center stations shows the high spatial variability of the methane concentration in the atmosphere over northern Eurasia. The complex and multifactor processes that determine the content of methane in the atmospheric surface layer result in noticeable spatial and interannual deviations from the mean seasonal cycle of its concentration, which can manifest themselves on both regional and global scales. It is possible that the resumed increase in the content of methane in the Earth’s atmosphere recorded in 2007 (after its relative stabilization in the early 2000s) at the global monitoring network was also caused, to some extent, by the anomalously warm winter of 2006–2007 in northern Europe and western Siberia.     

Analysis of variability of the CO, NO2, and O3 contents in the troposphere near St. Petersburg

The space-time variability of the fields of CO, NO₂, and O₃ concentrations and contents in the troposphere of northwestern Russia is analyzed on the basis of experimental data and the results of numerical modeling. The influence that the St. Petersburg emission has on the concentrations and contents of CO, NO₂, and O₃ in the troposphere is estimated for March 2006. A comparison of the measurements of the total CO content and the tropospheric NO₂ content with the results of modeling showed a qualitative and, in come cases, quantitative agreement between the results of calculations and experimental data. When synoptic conditions are determined, the St. Petersburg train can be detected at a distance of more than 300 km, which can affect the atmospheric air quality in adjacent countries.     

Spectroscopic measurements of total CFC-11 freon in the atmosphere near St. Petersburg

On the basis of ground based measurements of the infrared spectra of solar radiation with a high spectral resolution, estimates of total CFC-11 freon content in the atmosphere near St. Petersburg in January and May 2009 have been yielded in Russia for the first time. These data are conformed to various independent measurements within the limits of spectroscopic measurement errors.     

台湾地区湖泊甲烷释放量

本研究首次对台湾湖泊的甲烷释放量化评估,以期了解湖泊在台湾地区甲烷总释出量,研究主要利用两种方式进行,一是收集箱实测法,大多运用在交通便利地区,使用甲烷收集箱,定时收集甲烷气,进行浓度分析后,进而估算释放量,另一是利用水汽浓度差估算法,大多运用在交通不便地区,以水体内及接近水体的空气甲烷浓度差,考虑风速及利用理论方程式估算甲烷释放通量,两方法所得到的甲烷释放通量误差在一次方左右。     

Variations in the column-average dry-air mole fractions of CO2 in the vicinity of St. Petersburg

The results obtained from ground-based spectroscopic measurements of column-average dry-air mole fractions of CO₂ in the atmosphere over the St. Petersburg region are given for the period April 2009–October 2011 (～900 measurement runs, 151 measurement days). These results show significant variations in the CO₂ mixing ratio in the atmosphere over the St. Petersburg region. The minimum value of this mixing ratio (373.1 ppm) was observed on April 27, 2011, and its maximum value (420.8 ppm) was observed on February 10, 2010. The typical seasonal behavior of the CO₂ mixing ratio with its summer minimum was observed in 2009. In July 2010 and 2011, the values of the CO₂ mixing ratio increased apparently due to high air temperatures. In 2010 an additional contribution to this increase in the CO₂ mixing ratio could have been made by strong natural fires.     

Background component of methane concentration in surface air (Obninsk monitoring station)

We present measurement data from February 1998 to January 2014 obtained by Fourier spectroscopy for bulk methane concentrations in surface air samples. We have excluded the results of individual measurements of high methane concentrations arising at a temperature inversion and during fires to separate the monthly mean concentrations into the regional natural background concentration of methane and its anthropogenic addition. A seasonal concentration has been separated from the background concentration. Spectral analysis reveals a large number of composite oscillations of variations in the background methane concentra- tion with periods of 3 to 126 months. A model with the use of empirical parameters of these oscillations describes the temporal changes in the methane concentration with an error of less than 3%. The anthropogenic addition of CH₄ in the atmosphere is largely of a random character. Over 16 years of observations, its increase was ~23.7 ppb, which has resulted in an increase in the total CH₄ concentration by the same amount.     

Estimates of changes in the rate of methane sink from the atmosphere under climate warming

The temperature dependence of the methane oxidation rate is estimated. The methane lifetime in the atmosphere is shown to decrease by about 3% from 1900 to 2005. The overwhelming fraction of the total methane content is removed from the atmosphere at intratropical latitudes during the daytime. The methane oxidation rate growth due to the temperature increase in the troposphere generates negative feedback in the methane cycle and, accordingly, climatic feedback with the same sign. According to the estimates performed, the halt in methane concentration growth in the atmosphere observed in recent years can be associated with a decrease in the lifetime of methane in the atmosphere. According to the results of numerical experiments with the climatic model of the Institute of Atmospheric Physics, Russian Academy of Sciences (IAP RAS), the climatic effect of negative feedback of the tropospheric temperature and the methane lifetime in the atmosphere is not large and is comparable with the climatic forcing of the methane emission growth from bog ecosystems.     

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.     

Studying seasonal variations in carbonaceous aerosol particles in the atmosphere over central Siberia

The results of 2-year (2010–2012) measurements of the concentrations of organic carbon (OC) and elemental carbon (EC), which were taken at the Zotino Tall Tower Observatory (ZOTTO) Siberian background station (61° N, 89° E), are given. Despite the fact that this station is located far from populated areas and industrial zones, the concentrations of OC and EC in the atmosphere over boreal forests in central Siberia significantly exceed their background values. In winter and fall, high concentrations of atmospheric carbonaceous aerosol particles are caused by the long-range transport (~1000 km) of air masses that accumulate pollutants from large cities located in both southern and southwestern regions of Siberia. In spring and summer, the pollution level is also high due to regional forest fires and agricultural burning in the steppe zone of western Siberia in the Russian–Kazakh border region. Background concentrations of carbonaceous aerosol particles were observed within relatively short time intervals whose total duration was no more than 20% of the entire observation period. In summer, variations in the background concentrations of OC closely correlated with air temperature, which implies that the biogenic sources of organic-particle formation are dominating.     

Nitrogen dioxide in the air basin of St. Petersburg: Remote measurements and numerical simulation

The results of ground-based and satellite spectroscopic measurements of the tropospheric NO₂ content near St. Petersburg in January–March 2006 are presented. It is shown that the increased concentrations of NO₂ observed in St. Petersburg and its vicinities in this period were caused by NO₂ accumulation due to unfavorable weather conditions, which is confirmed by an analysis of meteorological data and the results of a numerical simulation of the dispersion of urban air pollutants. Data from satellite and ground-based measurements agree with each other satisfactorily (a correlation coefficient of 0.5) and with model calculations of tropospheric NO₂ conducted for the coordinates of a station of ground-based measurements (a correlation coefficient of 0.6). The HYSPLIT dispersion model also made it possible to estimate the scale of the NO₂ spatial-temporal variability in the near-surface layer in the vicinities of St. Petersburg.     

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).     

Determination of carbon monoxide pollution of the atmosphere over Moscow with a spectroscopic method

The results of measurements of the total content of carbon monoxide in an atmospheric column over Moscow and the Zvenigorod Scientific Station (ZSS) are given for the period 1993–2005. The simultaneous measurements of the regional background contents of carbon monoxide over a rural area (ZSS) and over Moscow made it possible to isolate an urban portion of the CO content. The total content of CO over the city varies significantly from day to day from values close to the background value to values that are 2.5–3 times greater than the background value. The number of days with such a CO content is 5% of the total number of measurement days. Such a CO content is most often observed during the cold seasons. During the warm seasons, in most of the cases, slight excesses of the CO background value are observed in the urban atmosphere. Variations in the CO content are determined mainly by wind-velocity variations and temperature inversions. In 2002, the high CO concentrations were due to forest and peatbog fires. On some days, over the ZSS, the concentrations of CO were high as never before. Over this period (12 years), the CO content in the surface air layer over the city did not increase.     

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.     

Comparison of Ground-Based Measurement Results of Total Ozone near St. Petersburg

Izvestiya, Atmospheric and Oceanic Physics - This paper compares the results of ground-based measurements of the total ozone content (TOC) near St. Petersburg for the period of 2009–2020. The...     

Variations in the total column amounts of carbon monoxide and methane in the Antarctic atmosphere

The results of measuring the total contents of carbon monoxide and methane via the method of solar-absorption spectroscopy are presented. The measurements were performed at the Molodezhnaya Station in 1977–1978, at the Mirny Observatory from 1982 to 1992, and at the Novolazarevskaya Station from 2003 to 2006. The character of seasonal variations in the contents of these gases in the Antarctic atmosphere is described and compared to the intra-annual variation of their surface concentrations measured at the Syowa Station (Japan). Synchronous intra-annual variations in the contents of carbon monoxide in the atmospheric column and in its surface concentrations are observed, while the spring maximum content of methane is observed three months after the maximum of its surface concentration. Synchronous seasonal variations in the total content of methane and ozone are observed, which makes it possible to suggest that the Antarctic circumpolar vortex has a significant influence on the characteristics of the vertical distribution of methane during Antarctic spring. Quantitative estimates of the parameters of multiyear variations in the contents of CO and CH₄ are given. The content of methane was increasing (although with different rates) during the entire observation period 1977–2006. The content of CO was observed to increase until 1992 and to decrease during 2003–2006.     

Ground-based measurements of total column of hydrogen chloride in the atmosphere near St. Petersburg

We present ground-based spectroscopic measurements of the total hydrogen chloride in the atmosphere of Peterhof near St. Petersburg from April 2009 to March 2012. The well-known computer code SFIT-2 (Zephyr-2) was used to interpret the spectra of the solar IR radiation. The random and systematic errors of total column (TC) HCl measurements did not exceed 3.8 and 4.5%. The seasonal behavior of TC HCl in Peterhof is characterized by the presence of a maximum in March–April and a minimum in October–November. There are also extremely small TC HCl values in January–February. The time behavior obtained for Peterhof agrees well with data from nearest stations in the NDACC international network. The ground-based measurements of the TC HCl were compared with satellite measurements with the help of ACE-FTS and MLS instruments. The direct comparisons of coincident (within a day) and collocated (within 500 km) satellite and ground-based measurements showed a correspondence of results within their total errors.