Evaluation of chemical ozone loss in the stratosphere over the Kola Peninsula in the 2002/2003 winter from microwave sounding data

From long-term observations of ozone evolution in the stratosphere of the Kola Peninsula in the 2002/2003 winter, the rates of chemical destruction of ozone and its net loss at isentropic levels of 530 K (an altitude of about 22 km) and 465 K (an altitude of about 19 km) ar evaluated with consideration for diabatic descent of air masses. These rates were ?18.6±3.3 and ?14.3±2.9 ppb/day and the net loss of ozone due to its chemical destruction over the period from December 1, 2002, to March 5, 2003, reached 1.77±0.33 ppm and 1.36±0.29 ppm, respectively. At the lower level, these data are in satisfactory agreement (to within measurement errors) with other measurements that were taken at that time. At a potential-temperature level of 530 K, the ozone loss in the 2002/2003 season evaluated from our data and from similar microwave measurements performed in Kiruna (Sweden) virtually coincides and testifies to the fact that the net loss increases with altitude. These inferences are inconsistent with the results obtained with the Match technique and the method of averaging over a vortex, which indicate that the ozone loss decreases with altitude. However, since polar stratospheric clouds were detected regularly in December and early January at levels up to 600 K or higher, it may be suggested that the ozone loss at these altitudes can be comparable to the values found for isentropic levels of 465 to 475 K.     

Anomalous Ozone Depletion in the Arctic from January to April 2020: Polar Vortex Dynamics under the Influence of Planetary Waves

Izvestiya, Atmospheric and Oceanic Physics - In the winter–spring period of 2020, the unprecedented destruction of stratospheric ozone over the Arctic (in terms of duration and depth) was...     

Interhemispheric distinctions between the polar vortex positions in the winter stratosphere and mesosphere from measurements with a SABER instrument aboard the TIMED satellite

Distinctions between the longitudinal structures of circulation in the stratosphere and mesosphere/lower thermosphere of the Northern and Southern hemispheres are investigated on the basis of the temperature and geopotential distributions obtained with a SABER instrument (TIMED satellite) in the months of February and August in 2002–2005. The positions of the winter cyclone and polar vortex at stratospheric and mesospheric heights in 2002–2005 are compared to the climatic data over 1978–1998. At stratospheric heights, the mean position of the polar vortex’s center over several years changed insignificantly during the specified years (several degrees in latitude and longitude) in both the Southern and Northern hemispheres. At mesosphere/lower thermosphere heights, the polar vortex occupies the same position in the Southern Hemisphere each year during 2002–2005, and this position agrees with the estimates for 1996–1997. Parameters of stationary planetary waves with the zonal wave number 1 (SPW1) in the fields of temperature, geopotential, and wind are calculated from data on the temperature and geopotential. The height profiles of SPW1 amplitudes and phases calculated from the SABER instrument data for August in the Southern Hemisphere are in good agreement with the profiles of amplitudes and phases obtained from the direct wind measurements with HRDI and WINDII instruments. A strong interannual variability of SPW1 parameters is observed in the Northern Hemisphere. The calculation of the Eliassen-Palm flux and its divergence has shown that SPW1 penetrates into the mesosphere mainly from the stratosphere and slows down the zonal mean flux. However, in the Southern Hemisphere, there is a regular additional SPW1 source with the center at a height of about 65 km and a latitude of 55°S. Such a SPW1 source is, on average, absent in the Northern Hemisphere during 2002–2005; however, in some years (for example, in February 2004), its existence is possible.     

Combined chemistry-climate model of the atmosphere

A combined three-dimensional global model of the chemistry and dynamics of the lower and middle atmosphere (up to 90 km from the Earth’s surface) is described. With the use of this model within the AMIP2 (1979–1995) program, numerical calculations were performed with consideration for the interactive coupling between the ozone content, radiation heating, and atmospheric circulation. Comparisons were made between calculated and observed data on the ozone content and temperature. Heterogeneous processes on the surface of polar stratospheric clouds were shown to be important for a correct simulation of the spatial and temporal distribution of atmospheric ozone.     

Modeling the variability of gas and aerosol components in the stratosphere of polar regions

A thermodynamics-microphysics model of the formation and evolution of stratospheric clouds is developed. This model was integrated into the global chemistry-climate model of the lower and middle atmosphere. Model experiments on the study of the evolution of the gas and aerosol compositions of the Arctic and Antarctic atmosphere were performed. The results of an investigation into the observed differences of changes in the contents of gaseous impurities and aerosol in polar regions showed that the presence of nitrification in the Antarctic and its absence in the Arctic are the main factors controlling distinctions between the formation of a full-value ozone hole in the Antarctic and only occasional “mini-holes” in the Arctic.     

Relationships between interannual variations in stratospheric warmings, tropospheric circulation, and sea surface temperature in the Northern Hemisphere

The leading modes of interannual and long-term variations in the stratospheric and tropospheric circulation and total ozone (TOMS data) and their relations to Northern Hemisphere sea surface temperature (SST) anomalies are investigated using the monthly mean NCEP/NCAR reanalysis data for the winter months of 1958–2003. Strong correlations are indicated between the interannual total ozone variations over Labrador and the North Atlantic and changes in the stratospheric polar vortex. The onset of major stratospheric warmings is connected not only with the strengthening of westerlies at the 500-hPa level in the midlatitude Atlantic, but also with the weakening of tropospheric winds over the north of eastern Siberia and strengthening over the Far East. In years with major stratospheric warmings, abnormally cold winters are observed in Eurasia, especially in eastern Siberia and northeastern China. The calculated simultaneous (with no time lags) correlations of the stratospheric circulation changes with El Niño/La Niña events give evidence of low correlations between the tropical Pacific SST anomalies and the stratospheric dynamics in the Arctic. However, there are high correlations of the extratropical Pacific and Atlantic SST anomalies with interannual tropospheric and stratospheric circulation variations, the stratospheric dynamics being more strongly connected with Pacific SST than with Atlantic SST anomalies. The interannual changes in tropospheric circulation are coupled to SST anomalies in both the Pacific and the Atlantic. Mechanisms of long-term changes in the interactive ocean-atmosphere-ozone layer system are discussed.     

A very deep ozone minihole in the Northern Hemisphere stratosphere at mid‐latitudes during the winter of 2000

Ozone miniholes appear on total ozone maps as localized ozone minima with horizontal extents of a few hundreds of kilometres. They are characterized by a rapid and small‐scale appearance of a columnar ozone decrease with an equally rapid recovery after a few days. They are frequently observed at Northern Hemisphere mid‐latitudes in winter. Evolving too rapidly to be the result of an ozone chemical destruction, miniholes should be the result of meteorological processes. According to some authors, miniholes should be due to the northeast motions of air patches with low total ozone content. However, several studies attribute the formation of ozone miniholes to the uplift of air masses, which decreases the ozone columnar content by simply decreasing the pressure thickness of the ozone layer, without changing the mixing ratio. According to these studies, the latter mechanism explains the main reduction of ozone that occurs between the tropopause and the ozone maximum during an ozone minihole event. A region of extreme low ozone values passed over Europe from 27 to 30 November 2000. The total ozone values were measured with the Total Ozone Mapping Spectrometer (TOMS). A radio sounding, launched on 29 November 2000 from Payerne at the place and time of the deepening of the minihole, allows us to perform a detailed analysis of its formation mechanism. It is shown that the uplift of isentropic surfaces plays an important role in the columnar ozone decrease and explains the lower part of the depleted ozone profile. However, the deepening of the minihole is explained by another mechanism: namely, at this time the minihole air column intersects the polar vortex at high altitudes and then encounters ozone‐poor air masses.     

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%.     

Spectral-temporal structure of variations in the atmospheric total ozone in central Eurasia

The results of long-term (1980–2003) systematic measurements of the total ozone content at the Issyk Kul station (42.6° N, 77.0° E; 1650 m above sea level) are presented. The statistical characteristics and spectral structure of variations in the total ozone and the main tendencies of its temporal variability are determined. It is found that the total ozone content decreased in 1980–2003 at an average rate of (?1.29±0.08) DU/yr. The results of Fourier and wavelet analyses have shown that only oscillations with periods of 12, 27–29, and 102–105 months are rather stable and can be represented as harmonic oscillations. Oscillations with periods shorter than six months have the character of periodically arising pulsations. Among these, oscillations with periods of 27–29 and 34–37 days can be distinguished. It is noted that the spectral-temporal structure of variations in the total ozone content obtained from ground-based measurements at the Issyk Kul station is in good agreement with the corresponding structure obtained from TOMS satellite measurements.     

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.     

Study of Ozone Layer Variability near St. Petersburg on the Basis of SBUV Satellite Measurements and Numerical Simulation (2000–2014)

A comparison between the numerical simulation results of ozone fields with different experimental data makes it possible to estimate the quality of models for their further use in reliable forecasts of ozone layer evolution. We analyze time series of satellite (SBUV) measurements of the total ozone column (TOC) and the ozone partial columns in two atmospheric layers (0–25 and 25–60 km) and compare them with the results of numerical simulation in the chemistry transport model (CTM) for the low and middle atmosphere and the chemistry climate model EMAC. The daily and monthly average ozone values, short-term periods of ozone depletion, and long-term trends of ozone columns are considered; all data sets relate to St. Petersburg and the period between 2000 and 2014. The statistical parameters (means, standard deviations, variations, medians, asymmetry parameter, etc.) of the ozone time series are quite similar for all datasets. However, the EMAC model systematically underestimates the ozone columns in all layers considered. The corresponding differences between satellite measurements and EMAC numerical simulations are (5 ± 5)% and (7 ± 7)% and (1 ± 4)% for the ozone column in the 0–25 and 25–60 km layers, respectively. The correspondent differences between SBUV measurements and CTM results amount to (0 ± 7)%, (1 ± 9)%, and (–2 ± 8)%. Both models describe the sudden episodes of the ozone minimum well, but the EMAC accuracy is much higher than that of the CTM, which often underestimates the ozone minima. Assessments of the long-term linear trends show that they are close to zero for all datasets for the period under study.     

Integral microphysical parameters of stratospheric background aerosol for 2002–2005 (the SAGE III satellite experiment)

The surface area and volume densities (S and V) of the particles of stratospheric background aerosol in the 15–20 km and 20–25 km layers for 2002–2005 were obtained from measurements of the aerosol extinction coefficient with the SAGE III instrument by using the linear-regression method of solving the inverse problem. The measurements were taken within the latitudinal belts 43°–80°N and 34°–58°S. The spatial and temporal dependences of S and V demonstrate homogeneous distribution fields in summer, whereas noticeable inhomogeneities are observed in winter and early spring. In all years of the measurements, an increase in the integral characteristics of stratospheric background aerosol was observed during the fall-to-winter transition period. Longitudinal variations in S and V can be both slight and significant (50–70%). Analysis of the interannual variability of the mean areas and volumes of aerosol particles shows that their minima (as a rule) were observed in 2002 and their maxima were observed in 2005. In most of the cases, no monotonic annual variations in the aerosol characteristics are noted. The dependence of the aerosol parameters on the phase of the quasi-biennial oscillations of zonal wind in the stratosphere is observed. The data obtained for 2002–2005 are, on the whole, in good agreement with the climatological data obtained for 1996–1999.     

Changes in Vertical Distribution and Column Content of NO<Subscript>2</Subscript> under the Influence of Sudden Stratospheric Warmings

Characteristic features of changes in the vertical distribution and column content of NO₂, total ozone, and stratospheric temperature have been revealed as a result of major sudden stratospheric warmings (SSWs). Strong negative anomalies of column NO₂, total ozone and stratospheric temperature are caused by the displacement of the stratospheric circumpolar vortex aside from the pole. Strong positive anomalies of column NO₂ and total ozone are observed more frequently under SSWs accompanied by splitting of the stratospheric circumpolar vortex and are caused by the transport of stratospheric air from the low latitudes. Major SSWs can lead to significant changes in the vertical profile of NO₂. The changes in different stratospheric layers can be opposite to each other when the edge of the polar vortex is over a site of ground-based observations.     

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.     

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].     

Prognostic estimations of the atmospheric ozone content in the first half of the 21st century

New prognostic estimates are obtained for the potential variability of the atmospheric ozone content in the first half of the 21st century. The calculations are based on models of gas composition and general circulation in the lower and middle atmosphere and on the scenarios of the World Meteorological Organization (WMO). It is shown that the rate of ozone content increase will be controlled to a considerable extent by variations in stratospheric temperature. Even though the contents of atmospheric chlorine and bromine are not reduced, contrary to the WMO prediction, and remain at the present-day levels, the continuation of stratospheric cooling will lead to a rapid recovery of the ozone content to its level characteristic of the 1980s. Model experiments on variations in the stratospheric aerosol content have shown that an increase in the aerosol concentration will not affect the rate of ozone recovery in the atmosphere during reduced emissions of chlorine and bromine gases if the stratospheric temperature remains lowered. Numerical experiments have also shown that the simultaneous anthropogenic action on the contents of halogen gases and on the lower-stratosphere temperature can reduce the adverse effects of Freons and halons on the ozone layer.     

The role of sulfate aerosol in the formation of cloudiness over the sea

We estimate the impact of sulfate aerosols on cloudiness formation over the sea in the middle troposphere and the involvement of these particles in the formation of polar stratospheric clouds (PSCs) in the lower stratosphere. The first of these problems is solved using a combined model of moist convection and the formation of cloudiness and sulfate aerosols in the troposphere and lower stratosphere over the sea, incorporating natural emissions of sulfur-containing compounds. We have found that a significant source of condensation nuclei in the troposphere is the photochemical transformation of biogenic dimethyl sulfide (in addition to NaCl). The results of numerical experiments indicate that the absence of sulfate aerosols hinders the cloudiness formation over the sea in the middle and upper troposphere. The problem of sulfate aerosol involvement in the formation of supercooled ternary solutions (STSs) (PSC Type Ib) in the lower stratosphere is solved using a mathematical model of global transport of multicomponent gas pollutants and aerosols in the atmosphere. Using the combined model, numerical experiments were performed for the winter season in both hemispheres. Sulfate aerosols were found to really participate in the formation of STS particles. Without their participation, the formation of STS particles in the lower stratosphere would be hindered. We present the results of numerical calculations and discuss the distribution of concentrations of gaseous nitric and sulfuric acids, as well as mass concentrations of these components in STS particles.     

Polar stratospheric clouds from satellite observational data

The spectral aerosol-extinction coefficients (SAECs) obtained from SAGE III measurements are used to study the physical and integral microphysical characteristics of polar stratospheric clouds (PSCs). Different criteria for PSC identification from SAEC measurements are considered and analyzed based on model and field measurements. An intercomparison of them is performed, and the agreement and difference of the results obtained with the use of different criteria are shown. A new criterion is proposed for PSC identification, which is based on the estimate of how close the measured vector of the spectral attenuation coefficient is to a model distribution of the PSC ensemble. On the basis of different criteria, cases of PSCs are isolated from all SAGE III observations (over 30000). All selection criteria lead to a qualitatively and quantitatively similar space-time distribution of the regions of PSC localization. The PSCs observed in the region accessible to SAGE III measurements are localized in the latitudinal zones 65°–80° in the Northern Hemisphere and 45°–60° in the Southern Hemisphere during the winter-spring period. In the Northern Hemisphere, PSCs are observed within the longitudinal zone 120° W–100° E with the maximum frequency of PSC observation in the vicinity of the Greenwich meridian. In the Southern Hemisphere, the region of PSC observation is almost the same in longitude but with a certain shift in the maximum frequency of PSC observation to the west. This maximum is observed in the vicinity of 40°W, and the region of usual PSC observation is the neighborhood of 60° of the maximum’s longitude. The physical parameters of PSCs are estimated: the mean heights of the lower and upper boundaries of PSCs are 19.5 and 21.9 km, respectively, and the mean cloud temperature is 191.8 K. The integral microphysical parameters of PSCs are estimated: the total surface of NAT particles S _NAT = 0.41 μm²/cm³; the total volume of NAT particles V _NAT = 1.1 μm³/cm³; and, for all aerosol and cloud particles together, S is 2.9 ± 1.5 at a standard deviation of 2.7 μm²/cm³ and V is 2.8 ± 1.5 at a standard deviation of 4.2 μm³/cm³. A high frequency of PSC occurrence and high values of S and V in PSCs both for all particles and for NAT particles have been noted in January–February 2005 as compared to the rest of the period of SAGE III measurements for 2002–2005.     

Effect that jet streams have on the vertical ozone distribution and characteristics of tropopause inversion layer in the far east region

The paper describes a lidar and presents the results of lidar sensing of the vertical ozone distribution (VOD); the lidar measurements are analyzed together with data from a network of meteorological stations situated along the 132° E meridian. VODs over Primorye and Japan in the winter period are compared. An analysis showed that an interrelation exists between the subtropical jet stream and the structures of VOD and tropopause inversion layer. Specifically, the region of the VOD local maximum above the tropopause is in the upper part of the tropopause inversion layer and the width of the maximum depends on the distance from the core of the subtropical jet stream. It is found that the local ozone minimum in the lower stratosphere corresponds to the local minimum of the squared Brunt-Vaisala frequency within this same altitude range in the winter season, when two tropopauses frequently overlap. It is conjectured that the local ozone maximum and tropopause inversion layer may be associated with mixing processes in the layer where stratospheric and tropospheric circulation cells come into contact near the core of the subtropical jet stream.     

A quasitropical cyclone over the Black Sea: Observations and numerical simulation

A long-living mesoscale cyclone observed over the Black Sea in September 2005 was characterized by a high wind velocity (25 m/sec) and induced an abnormal lowering of the sea-surface temperature (by more than 10°C). We performed the numerical simulation of this cyclone by using the MM5 model and the data of global operative analysis. The evolution of the cyclone and its structure similar to the structure of a tropical cyclone are reproduced. The primary azimuthal and secondary radial circulations, the clear-sky eye with warm core at medium levels, and the eyewall with strong air updraft and intense convection and precipitation are well visible. The fluxes of sensible and latent heat on the sea surface played the key role in the initiation and development of this cyclone. __________ Translated from Morskoi Gidrofizicheskii Zhurnal, No. 3, pp. 41–55, May–June, 2008.