Seasonal features of quasi-biennial variations of NO<Subscript>2</Subscript> stratospheric content derived from ground-based measurements

Seasonal and latitudinal distributions of amplitudes of quasi-biennial variations in total NO₂ content (NO₂ TC), total ozone content (TOC), and stratospheric temperature are obtained. NO₂ TC data from ground-based spectrometric measurements within the Network for the Detection of Atmospheric Composition Change (NDACC), TOC data from satellite measurements, and stratospheric temperature data from ERA-Interim reanalysis are used for the analysis. The differences in the NO₂ TC diurnal cycles are identified between the westerly and easterly phases of the quasi-biennial oscillations (QBO) of equatorial stratospheric wind. The QBO effects in the NO₂ TC, TOC, and stratospheric temperature in the Northern (NH) and Southern (SH) hemispheres are most significant in the winter–spring periods, with essential differences between the NH and SH. The NO₂ TC in the Antarctic is less for the westerly phase of the QBO than that for the easterly phase, and the NO₂ TC quasi-biennial variations in the SH mid-latitudes are opposite of the variations in the Antarctic. In the NH, the winter values of the NO₂ TC are generally less during the westerly QBO phase than during the easterly phase, whereas in spring, on the contrary, the values for the westerly QBO phase exceed those for the easterly phase. Along with NO₂, the features of the quasi-biennial variations of TOC and stratospheric temperature are discussed. Possible mechanisms of the quasi-biennial variations of the analyzed parameters are considered for the different latitudinal zones.     

Quasi-biennial variations in ozone and meteorological parameters over western Europe from ozonesonde data

Quasi-biennial variations in vertical profiles of ozone, temperature, air pressure, and zonal and meridional wind velocities are analyzed from ozonesonde data obtained at the western European stations of Lindenberg, Hohenpeissenberg, and Payerne. The effect of quasi-biennial variations manifests itself variously in different variables and is nonuniform in altitude. The period of quasi-biennial variations is not constant, and the values of the mean period group mainly around 2 and 2.5 years. As in the North American region, the effects of quasi-biennial variations in different parameters of the stratosphere and troposphere over western Europe are due to a combination of the effects of the quasi-biennial oscillation (QBO) in the equatorial stratosphere, the El Niño-Southern Oscillation (ENSO), and the North Atlantic Oscillation (NAO). The observed 2.5-year variations in stratospheric ozone are related to the equatorial QBO to a larger extent in comparison with variations in other variables. It seems likely that a determining influence on variations in stratospheric wind and temperature is exerted by the ENSO. Variations in tropospheric and stratospheric parameters with a mean period of about 2 years are due to the ENSO and NAO effects.     

Effects of the equatorial quasi-biennial oscillation in the total ozone content over Russia

On the basis of ground-based measurements of total ozone content (TOC) over Russia and a number of neighboring states during 1973–2002, the amplitudes and phases of TOC variations caused by the quasi-biennial oscillation (QBO) of wind in the equatorial stratosphere are estimated for different regions and for the whole area. The seasonal dependence of the QBO effect in the TOC is analyzed. It is shown that the magnitude and even the sign of the effect depend on the relation between the equatorial QBO phase and the season. The regional empirical models of seasonally dependent QBO effects are constructed. It is found that the seasonal dependence of regional effects accounts for 4% (in the north of the area) to 20% (in the south) of the interannual variability of the TOC. The relation between the QBO effect and the 11-year cycle of solar activity is analyzed. Significant differences are revealed in the effects under the conditions of maximum and minimum solar activity. The QBO effects obtained from observations at Russian stations, satellite measurements with a TOMS instrument, and spectrometric observations of the TOC at western European stations are compared, and their satisfactory agreement is shown. An analysis of the results suggests that the QBO effects in the TOC over Russia are caused by several interacting factors and apparently reflect their regional properties.     

Sudden stratospheric warmings: statistical characteristics and influence on NO<Subscript>2</Subscript> and O<Subscript>3</Subscript> total contents

Statistical characteristics of major and minor sudden stratospheric warmings (SSWs) in the Northern Hemisphere (NH) for 1958–2015 are analyzed using data of NCEP-NCAR, ERA 40, and ERA-Interim reanalyses. Dependencies of the number of major SSWs with the displacement of the circumpolar stratospheric vortex and the number of minor SSWs on the phase of the quasi-biennial oscillation (QBO) of the equatorial stratospheric wind and on the level of solar activity (SA) in the 11-year solar cycle have been revealed. Major SSWs accompanied by a displacement of the polar vortex occur more often at a high level of SA and at the easterly phase of the QBO in the 50–40 hPa layer, while minor SSWs occur more often at a low SA level and at the westerly phase of the QBO. An analysis of spatiotemporal dynamics of the stratospheric polar vortex at major SSWs is performed. The most probable directions of vortex displacement caused by SSWs have been revealed. Influences of the major SSWs on the total contents of NO₂ and ozone, as well as on stratosphere temperature, are analyzed.     

Analysis of the influence that climatic variability has on the formation of the total-ozone-content field at extratropical latitudes of the Northern Hemisphere

Having applied the method of discriminant analysis to the TOMS data of satellite sounding of the total ozone content (TOC) in the March months of 1979–2008, the authors could make a new estimate of the TOC field variability in the Northern Hemisphere and interlongitudinal regularities of its changes under the action of climatic variability. The effects of temperature variations in the polar stratosphere, El Niño, and quasi-biennial oscillation (QBO) have proven comparable and reach 80 DU in some regions. The influence of the Arctic Oscillation (AO) reaches 40 DU. The regions of TOC variations and their location and dimensions change depending on the phases of QBO, AO, and El Niño-Southern Oscillation (ENSO). Three regions of increased TOC—over Europe, Eastern Siberia, and the Pacific Ocean—are formed in years with a warm stratosphere. A compensating TOC decrease takes place in the tropics and over Greenland. In the years of El Niño and the easterly QBO phase, the TOC increases over Europe and drops over the central Pacific, as well as to the south from 45° N. The AO controls the ozone growth over most of Eurasia at temperate latitudes and its weak drop over the Atlantic. It was impossible to obtain such quantitative estimates with the use of methods based on an independent analysis of the TOC series at individual points of the coordinate grid. Testing with the Monte Carlo method confirmed that the results obtained are significant with a probability of 95–99.9%.     

Quasi-biennial oscillation of wind in the low-latitude stratosphere and the winter wave activity of the atmosphere in the Northern Hemisphere

According to the Holton-Tan hypothesis [1], oscillations of the equatorial stratospheric wind change the conditions of the vertical and meridional propagation of planetary waves in extratropical regions, which can cause quasi-biennial oscillations (QBOs) at middle and polar latitudes. To verify the Holton-Tan hypothesis, the intensity of the winter wave activity of the atmosphere in the Northern Hemisphere was estimated at different phases of the quasi-biennial oscillation of the equatorial stratospheric zonal wind. As it turned out, a higher level of the wave activity expected at the easterly phase of the equatorial QBO is characteristic only of the period when the winter circulation is established. At the end of winter a higher level of the wave activity is observed at the westerly QBO phase, which contradicts the Holton-Tan hypothesis. Small but nevertheless noticeable distinctions in the wave activity at low tropospheric levels suggest that the quasi-biennial periodicity of the wave activity at middle latitudes can be caused by oscillations of synoptic processes between the predominantly zonal and meridional forms of the circulation, as was indicated by Pogosyan and Pavlovskaya [2, 3].     

On the influence of the 11-year cycle of solar activity on quasi-biennial variations in ozone and temperature in the Canadian sector of the arctic

An analysis of the high-latitude ozone balloon sounding data derived from Canadian stations shows that, in the maximum of the 11-year cycle of solar activity (SA), the ozone content in the lower stratosphere is higher than in the SA minimum and, in the SA maximum, the lower stratosphere is warmer and the troposphere is colder than in the SA minimum. The ozone and temperature responses to the equatorial quasi-biennial oscillation (QBO) in the opposite phases of the 11-year cycle of SA show substantial differences: in the SA maximum, the QBO effects in the ozone and temperature cover a wider range of heights, the maxima of the effects manifest themselves at 5–10 km higher, and their amplitudes exceed the amplitudes of the effects in the SA minimum. The results indicate that the QBO is one of the “conductors” of the influence of the 11-year SA cycle in the Canadian sector of the Arctic.     

Simulation of the quasi-biennial oscillations of the zonal wind in the equatorial stratosphere: Part I. Low-parameter models

The paper focuses on the simulation of the quasi-biennial oscillations (QBOs) of zonal velocity in the equatorial stratosphere. Low-parameter models are used to examine two mechanisms for excitation of the QBO: one through the interaction of planetary waves with the mean flow at critical levels and another through gravity-wave obliteration. The possible use of each of these mechanisms for generating the QBO is shown, the ranges of parameter values where this generation is possible are determined, and the dependences of the period and amplitude of the limit cycle on the model parameters are analyzed. A relative role of waves of different scales in the formation of the period of the oscillations of zonal wind is studied with a coupled model combining both mechanisms. The conditions that are required to reproduce the QBO in general circulation models are discussed.     

Interannual variations and trends in zonal mean series of total ozone, temperature, and zonal wind

The paper considers zonal mean (65° S–65° N, with a step of 5°) monthly mean NCEP/DOE reanalysis data on zonal wind and temperature at levels of 20 to 100 mb and the TOMS data of version 8 on total ozone (TO) for the period 1979–2005. The results of calculating linear-trend coefficients, correlation coefficients, and characteristic decay times and the data of spectral analysis are presented. In recent decades, the decrease in TO and the cooling of the lower stratosphere were accompanied by a weakening of the westerly wind. For deseasonalized series, the significance of their linear trends are evaluated with the use of the Monte Carlo method and it is shown that TO trends are significant at a level of 0.99 in extratropical latitudinal zones and that temperature trends are significant everywhere except in a narrow equatorial zone and in latitudes south of 50° S, whereas wind trends are significant only at a 50-mb level in the latitudinal belt 30°–50° in both hemispheres. According to the results of spectral analysis, for the majority of latitudinal zones, a triplet in the range of quasibiennial oscillations and oscillations with periods of about 4–6 and 9–13 years manifest themselves most persistently in the series of temperature, wind, and TO. Maximum correlation coefficients of the series of TO, wind, and temperature are observed over the equator, and, depending on altitude and latitude, TO variations may lag or lead temperature and wind variations in phase. Latitudinal distributions of characteristic decay times show an increase in this parameter in tropical and equatorial zones and its opposite behavior with altitude for temperature and wind fields.     

Effect of the 11-year cycle of solar activity on characteristics of the total ozone annual variation

The goal of the paper is an analysis of changes in the amplitude and phase characteristics of the annual variation (AC) of total ozone (TO) from ground-based and satellite (TOMS) measurements and their interpretation with a two-dimensional photochemical model. According to ground-based TO measurements, two characteristic types of quasi-decadal variations in the phase of the annual harmonic (AH) of total ozone have been noted: variations in phase and antiphase with solar activity (SA). Changes in the TO AH phase opposite to solar activity variation are noted the high latitudes of the North Atlantic region and in the tropical belt, and in-phase changes are observed in the middle and subtropical latitudes of both hemispheres. Variations in the TO AH amplitude (hence, in the TO AV amplitude) and in the annual mean TO usually coincide in phase with the SA cycle. Analysis of satellite data shows that the 0-phase of the AV and the phase of the AH of the zonal mean TO at middle latitudes vary synchronously with the 11-year solar cycle. Model simulations have shown that the stratospheric ozone influx to the middle latitudes increases in the fall and winter period during a period of maximum solar activity. This dynamic mechanism accounts for up to 30% of the winter ozone increase in the ozone maximum layer in the Southern Hemisphere midlatitudes during the solar maximum as compared with the solar minimum. In the northern midlatitudes, the dynamic mechanism makes the main contribution to ozone changes during the latter half of winter under SA variations. The stratospheric ozone inflow change induced by SA variations affects the annual variation of ozone.     

Numerical simulation of wave interactions during sudden stratospheric warming

Parameterizations of normal atmospheric modes (NAMs) and orographic gravity waves (OGWs) are implemented into the mechanistic general circulation model of the middle and upper atmosphere (MUA). Numerical experiments of sudden stratospheric warming (SSW) events are performed for climatological conditions typical for January and February using meteorological reanalysis data from the UK MET Office in the MUA model averaged over the years 1992–2011 with the easterly phase of quasi-biennial oscillation (QBO). The simulation shows that an increase in the OGW amplitudes occurs at altitudes higher than 30 km in the Northern Hemisphere after SSW. The OGW amplitudes have maximums at altitudes of about 50 km over the North American and European mountain systems before and during SSW, as well as over the Himalayas after SSW. At high latitudes of the Northern Hemisphere, significant (up to 50–70%) variations in the amplitudes of stationary planetary waves (SPWs) are observed during and after the SSW. Westward travelling NAMs have local amplitude maximums not only in the Northern Hemisphere, but also in the Southern Hemisphere, where there are waveguides for the propagation of these modes. Calculated variations of SPW and NAM amplitudes correspond to changes in the mean temperature and wind fields, as well as the Eliassen-Palm flux and atmospheric refractive index for the planetary waves, during SSW. Including OGW thermal and dynamical effects leads to an increase in amplitude (by 30–70%) of almost all SPWs before and during SSW and to a decrease (up to 20–100%) after the SSW at middle and high latitudes of the Northern Hemisphere.     

Simulation of the quasi-biennial oscillations of the zonal wind in the equatorial stratosphere: Part II. Atmospheric general circulation models

The problem of simulating quasi-biennial oscillations (QBOs) of zonal velocity in the equatorial stratosphere in atmospheric general circulation models is considered. In accordance with the results from Part I of this study on the basis of the models developed at the Institute of Numerical Mathematics of the Russian Academy of Sciences (INM RAS), the possibility of implementing (in these models) mechanisms of QBO excitation through both the interaction of planetary waves with the mean flow and breaking of short gravity waves is investigated. A new high-resolution 2° × 2.5° × 80 version of the INM RAS model is designed, a climate simulation with the two 2° × 2.5° × 39 and 2° × 2.5° × 80 versions of the INM RAS model is briefly described, results of spectral analysis of equatorial wave activity are presented, and the QBO formation processes in these models are considered in detail. For the new 2° × 2.5° × 80 model, realistic QBOs of zonal wind are obtained as the result of the action of both mechanisms.     

Effect of certain geo-and heliophysical factors on the variability of ozone and UV irradiance fields in the tropics

The variability of the fields of the total ozone content (TOC) and UV erythemal irradiance in the tropical region (30°S–30°N) is studied. The fields of monthly means of the TOC and erythemal irradiance that are based on the TOMS 8 and SBUV 8 satellite observations over the period from 1979 through 2003, with preliminarily eliminated the linear trend and the seasonal cycle, were used as the initial data. The application of the method of empirical orthogonal functions (EOFs) to analysis of initial series made it possible to identify the characteristic spatial and temporal patterns in the fields of TOC and UV-irradiance anomalies that are closely related to solar activity and elements of the atmospheric general circulation, such as the quasi-biennial oscillation and El Niño (La Niña) phenomena. Quantitative estimates and analysis of the fields of TOC and UV-irradiance variations are presented in the study. The revealed spatial, temporal, and phase relations of the fields of ozone variations to some geo-and heliophysical factors are used in the regression model proposed for estimating monthly means of TOC in the tropics and based on the EOF decomposition.     

Spectral characteristics of quasi-biennial oscillations of the equatorial stratospheric wind and the problem of synchronization

Spectral characteristics of the quasi-biennial oscillations (QBO) of the zonal velocity in the equatorial stratosphere are investigated in this work on the basis of data from the NCEP/NCAR and ERA40 reanalyses and numerical experiments with the atmospheric general circulation (GCM) model developed at the Institute of Numerical Mathematics, Russian Academy of Sciences (INM RAS). The problem of synchronizing QBO and semiannual oscillations (SAO) of the zonal velocity in the mesosphere is considered. It is shown that the process of synchronization to multiples of SAO periods is identifiable in the transition region between QBO and SAO. For all heights where QBO exist, their synchronization with SAO is expressed in the calculation of the period in terms of differences between the westerly maxima. The INM RAS GCM model is shown to satisfactorily reproduce the main spectral characteristics of QBO and SAO, as well as specific features of the variability of the QBO period obtained from reanalysis data. The possibility of synchronization with SAO or the annual cycle in the upper layers is shown on the basis of an investigation of QBO models with a small number of parameters, both for the absorption mechanism of planetary waves by the mean flow and for the breaking of short gravity waves. The QBO formation from different wave types, together with SAO and the annual cycle, can be considered a unified system of oscillations in the circulation of the equatorial upper atmosphere.     

Analysis of volcanogenic perturbations of the subarctic ozonosphere on the basis of space monitoring data

The response of the total ozone (TO) at subarctic latitudes to volcanic eruptions, products of which were injected into the stratosphere, is analyzed. It is established that the behavior of the series of average annual TO values according to the TOMS, SCIAMACHY, and GOME space equipment data averaged for 55°–65° N latitudes agrees with the activity of explosive volcanic eruptions. The series of the TO satellite monitoring instrumental data are extended by 200 years into the past using a reconstruction from the dendro-chronologic data. An analysis of the series of TO reconstructed values indicates that volcanogenic perturbations of the subarctic ozonosphere initiate long-term negative TO deviations. In this case, the TO negative deviation depth depends on the frequency of the ozonosphere volcanogenic perturbations and the phase of quasiperiodic oscillation cycles rather than on the strength of a single volcanic explosion.     

Manifestation of the Arctic Oscillation and El Niño-Southern Oscillation in the tropical stratosphere

Characteristics of the Arctic Oscillation and El Niño-Southern Oscillation effects manifested on interannual scales in the equatorial stratosphere are determined. Wavelet analysis of local phase shifts, coherence, and correlation is used to obtain correlation portraits of the largest factors of climate variability against the background of coherent variations in the equatorial stratospheric wind speed at the 50- and 15-hPa pressure levels. It is shown that the Arctic Oscillation and El Niño-Southern Oscillation signals may reach the tropical stratosphere. The signals are easily identified in a wide range of scales, including quasi-biennial, 3-to 5-year, and 10-to 11-year periods. The results obtained reflect a coherent pattern of the manifestation of these signals at the selected stratospheric levels. It is found that the El Niño-Southern Oscillation effect at periods close to 10–11 years reaches the stratospheric level rather rapidly, in the same or next month, while the effects of the Arctic Oscillation index are delayed by nine months. The estimates obtained show that a phase shift of almost 180° in the Arctic Oscillation index relative to the equatorial stratospheric wind occurred in almost all of the range of interannual periods in 1978 and 1992. For the El Niño-Southern Oscillation, an increase in local correlations on a scale of 3-to 5-year variations was observed in 1980–1990, a 180° phase shift occurred in 1992, and the correlation with stratospheric wind increased in 1992–2004. The estimates obtained are indicative of a change in the atmospheric circulation pattern that took place in the Northern Hemisphere in 1978–1991.     

Variations of the total content of carbon monoxide over Moscow megapolis

The results of the carbon monoxide total content measurements over Moscow and Zvenigorod for 2005–2008 are compared with the same data sets for Moscow 1986–2005 and Beijing, 1992–2007. Two identical medium resolution diffraction spectrometers (resolution 0.2 cm^?1) with solar tracking system were used. The CO total content measured simultaneously over the city and over Zvenigorod Scientific Station (ZSS) of the Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences (60 km west from Moscow). This method allows to isolate an urban part of CO content. The acoustic locator SODAR LATAN-3 measurements permitted us to study the influence of the carbon monoxide ventilation conditions upon level of pollution. Correlation coefficients between the urban part of CO content and average wind speed for cold and warm seasons were obtained. The data sets analysis showed a preeminent effect of the wind within boundary layer (up to 300 m) over the CO ventilation. The urban part of the CO content hasn’t increased in spite of more than quintuple increase of the motor-vehicles number in Moscow. An increase of the rural CO total column for the 1970–1985 has transformed into its virtually stable amount in between of 1986 to 2000, changed then to a decrease for 2001–2008. We noted the 2008 as “the year of the CO total column minimum” over the past decade. The effect of urban CO sources influence on the CO total column in rural area is small, i.e. on a level of 3% of the total number of measurements. The number of extremal daily values for Moscow is estimated as 5%, and 20% for Beijing.     

Total content of carbon monoxide in the atmosphere over Russian regions according to satellite data

Carbon monoxide (CO) total columns over European Russia (ER) and western Siberia (WS) have been analyzed using MOPITT (V5, TIR/NIR, L3) IR-radiometer data obtained in 2000–2014. High CO contents are revealed over large urban and industrial agglomerations and over regions of oil-and-gas production. A stable local CO maximum is observed over the Moscow agglomeration. Statistical characteristics of CO total columns observed in the atmosphere over ER and WS in 2000–2014 are presented. An analysis of long-term changes in CO content reveals nonlinear changes in the CO total column over northern Eurasia in 2000–2014. Results of a comparative analysis of annual variations in atmospheric CO contents over ER and WS are given. Based on Fourier analysis, empirical models of annual variations in total CO contents over ER and WS are proposed. Relations between regional CO contents and fire characteristics and between spatial CO distributions and features of large-scale atmospheric dynamics under conditions of weather and climate anomalies in the summers of 2010 in ER and 2012 in WS are analyzed. Data on total CO contents measured with a MOPITT satellite radiometer and a ground-based spectrometer operating at the Zvenigorod Scientific Station of the Obukhov Institute of Atmospheric Physics are compared.     

Quasi-decadal variations in total ozone content,wind velocity,temperature, and geopotential height over the Arosa station (Switzerland)

We present the results of the analysis of the phase relationships between the quasi-decadal variations (QDVs) (in the range from 8 to 13 years) in the total ozone content (TOC) at the Arosa station for 1932–2012 and a number of meteorological parameters: monthly mean values of temperature, meridional and zonal components of wind velocity, and geopotential heights for isobaric surfaces in the layer of 10–925 hPa over the Arosa station using the Fourier methods and composite and cross-wavelet analysis. It has been shown that the phase relationships of the QDVs in the TOC and meteorological parameters with an 11-year cycle of solar activity change in time and height; starting with cycle 24 of solar activity (2008–2010), the variations in the TOC and a number of meteorological parameters occur in almost counter phase with the variations in solar activity. The periods of the maximum growth rate of the temperature at isobaric surfaces 50–100 hPa nearly correspond to the TOC’s maximum periods, and the periods of the maximum temperature correspond the periods of the decrease of the peak TOC rate. The highest correlation coefficients between the meridional wind velocity and temperature are observed at 50 hPa at positive and negative delays of ~27 months. The times of the maxima (minima) of the QDVs in the meridional wind velocity nearly correspond to the periods of the maximum amplification (attenuation) rate of the temperature of the QDVs. The QDVs in the geopotential heights of isobaric surfaces fall behind the variations in the TOC by an average of 1.5 years everywhere except in the lower troposphere. In general, the periods of variations in the TOC and meteorological parameters in the range of 8–13 years are smaller than the period of variations in the level of solar activity.     

Connections of Precipitable Water Vapor and Total Ozone Anomalies over European Russia with the North Atlantic Oscillation: Specific Features of Summer 2010

Based on the measurements of precipitable water vapor (PWV) and total column ozone (TCO) from the MODIS satellite instruments (Aqua/Terra platforms), the connections between the North Atlantic Oscillation (NAO) and the anomalies in PWV and TCO over European Russia (ER) in summer 2010 are analyzed. It is found that the PWV (TCO) anomalies over the northern ER in summer 2010 positively (negatively) correlated with the NAO, and the local correlations reached 0.68 (–0.55). The physical mechanisms of the correlations are discussed. A comparative analysis of the relationships between the NAO and the regional PWV and TCO anomalies over ER during the summer seasons of 2000–2015 is carried out.