Ozone Anomalies Research Articles

Ozone Variability and Anomalies Observed during SENEX and SEAC4RS Campaigns in 2013.

Tropospheric ozone variability occurs because of multiple forcing factors including surface emission of ozone precursors, stratosphere-to-troposphere transport (STT), and meteorological conditions. Analyses of ozonesonde observations made in Huntsville, AL, during the peak ozone season (May to September) in 2013 indicate that ozone in the planetary boundary layer was significantly lower than the climatological average, especially in July and August when the Southeastern United States (SEUS) experienced unusually cool and wet weather. Because of a large influence of the lower stratosphere, however, upper-tropospheric ozone was mostly higher than climatology, especially from May to July. Tropospheric ozone anomalies were strongly anti-correlated (or correlated) with water vapor (or temperature) anomalies with a correlation coefficient mostly about 0.6 throughout the entire troposphere. The regression slopes between ozone and temperature anomalies for surface up to mid-troposphere are within 3.0-4.1 ppbv·K-1. The occurrence rates of tropospheric ozone laminae due to STT are ≥50% in May and June and about 30% in July, August and September suggesting that the stratospheric influence on free-tropospheric ozone could be significant during early summer. These STT laminae have a mean maximum ozone enhancement over the climatology of 52±33% (35±24 ppbv) with a mean minimum relative humidity of 2.3±1.7%.

Merged SAGE II, Ozone_cci and OMPS ozone profile dataset and evaluation of ozone trends in the stratosphere

Abstract. In this paper, we present a merged dataset of ozone profiles from several satellite instruments: SAGE II on ERBS, GOMOS, SCIAMACHY and MIPAS on Envisat, OSIRIS on Odin, ACE-FTS on SCISAT, and OMPS on Suomi-NPP. The merged dataset is created in the framework of the European Space Agency Climate Change Initiative (Ozone_cci) with the aim of analyzing stratospheric ozone trends. For the merged dataset, we used the latest versions of the original ozone datasets. The datasets from the individual instruments have been extensively validated and intercompared; only those datasets which are in good agreement, and do not exhibit significant drifts with respect to collocated ground-based observations and with respect to each other, are used for merging. The long-term SAGE–CCI–OMPS dataset is created by computation and merging of deseasonalized anomalies from individual instruments. The merged SAGE–CCI–OMPS dataset consists of deseasonalized anomalies of ozone in 10° latitude bands from 90° S to 90° N and from 10 to 50 km in steps of 1 km covering the period from October 1984 to July 2016. This newly created dataset is used for evaluating ozone trends in the stratosphere through multiple linear regression. Negative ozone trends in the upper stratosphere are observed before 1997 and positive trends are found after 1997. The upper stratospheric trends are statistically significant at midlatitudes and indicate ozone recovery, as expected from the decrease of stratospheric halogens that started in the middle of the 1990s and stratospheric cooling.

Comparison of long-term total ozone observations from space- and ground-based methods at Zhongshan Station, Antarctica

Total ozone errors for satellite observations at Zhongshan Station in Antarctica are characterized using their relative difference (RD) from ground-based Brewer observations during 1993–2015. All satellite total ozone observations slightly overestimated ground-based ones (with RD less than 4%). This is in contrast to conclusions drawn from global-scale validation studies, where main ground-based reference stations are located in middle latitudes. Given multiple total ozone data per day at Zhongshan Station, observed by a sun synchronous orbit satellite, measurements at the lowest solar zenith angle (SZA) show greatest consistency with Brewer ones, having an overall RD of −0.02–1.15%. Algorithm-retrieved total ozone data from the Total Ozone Mapping Spectrometer (TOMS), including Solar Backscatter Ultra Violet (SBUV), TOMS-Earth Probe (EP), Ozone Monitoring Instrument (OMI)-TOMS, show best agreement with ground-based values; followed by the Global Ozone Measurement Experiment-type Direct Fitting (GOD-FIT) algorithm for the GOME-2A, and finally the Differential Optical Absorption Spectroscopy (DOAS) —Algorithm retrieved products for satellites-detectors of Global Ozone Measurement Experiment (GOME), Scanning Imaging Absorption spectroMetr for Atmospheric CHartographY (SCIAMACHY), and OMI. Satellite total ozone RD presents some statistical characteristics, but no specific trends. DOAS and GOME-2A algorithms have values that significantly increase, when the SZA is above 60°–70°, whereas values for GOME-2A decrease, when the SZA is 80–85°. Satellite total ozone RD is a minimum, when the Brewer total ozone is 300–350 DU, with an obvious increase in RD values for DOAS- and GOME-2A, when the Brewer total ozone is 150–300 DU. Satellite total ozone RD obviously increases, as the time difference between satellite overpasses and Brewer measurements grows. Specifically, RD rises as the absolute time difference increases to more than 4 h, yielding an OMI-TOMS RD of more than 10% as this difference increases to 8 h. The DOAS- RD may be up to 15%, while GOME-2A RD does not exceed 10%. The satellite total ozone RD may reach −5%, as the distance between the satellite overpass pixel and the station become more than 100 km. Possibly because of the discrepancy in surface albedo, the TOMS-algorithm retrieved total ozone produced underestimation, when the pixel on the south-east side of the station (the Antarctica continent) is used, but overestimation on the north-west side of the station (the Indian Ocean). Consistency between space and ground-based total ozone data is least for the “ozone hole”. Typically, the RD of TOMS-algorithm retrieved total ozone is within 1%/10 yr. Thus, the SBUV and Brewer monthly averaged total ozone anomalies from 1996 to 2015 were 1%/10 yr and 0.9%/10 yr, respectively. Both indicate slight, but consistent, ozone layer recovery.

A Study of Ozone Anomaly of 2011 in the Northern Hemisphere Based on Aura Satellite Data

A Study of Ozone Anomaly of 2011 in the Northern Hemisphere Based on Aura Satellite Data

Influence of low ozone episodes on erythemal UV-B radiation in Austria

This study investigates the influence of low ozone episodes on UV-B radiation in Austria during the period 1999 to 2015. To this aim observations of total column ozone (TCO) in the Greater Alpine Region (Arosa, Switzerland; Hohenpeissenberg, Germany; Hradec Kralove, Czech Republic; Sonnblick, Austria), and erythemal UV-B radiation, available from 12 sites of the Austrian UV-B monitoring network, are analyzed. As previous definitions for low ozone episodes are not particularly suited to investigate effects on UV radiation, a novel threshold approach—considering anomalies—is developed to provide a joint framework for the analysis of extremes. TCO and UV extremes are negatively correlated, although modulating effects of sunshine duration impact the robustness of the statistical relationship. Therefore, information on relative sunshine duration (SDrel), available at (or nearby) UV-B monitoring sites, is included as explanatory variable in the analysis. The joint analysis of anomalies of both UV index (UVI) and total ozone (∆UVI, ∆TCO) and SDrel across sites shows that more than 65% of observations with strongly negative ozone anomalies (∆TCO < −1) led to positive UVI anomalies. Considering only days with strongly positive UVI anomaly (∆UVI > 1), we find (across all sites) that about 90% correspond to negative ∆TCO. The remaining 10% of days occurred during fair weather conditions (SDrel ≥ 80%) explaining the appearance of ∆UVI > 1 despite positive TCO anomalies. Further, we introduce an anomaly amplification factor (AAF), which quantifies the expected change of the ∆UVI for a given change in ∆TCO.

Ozone, water vapor, and temperature anomalies associated with atmospheric blocking events over Eastern Europe in spring - summer 2010

Using data from the AIRS satellite instrument (V6, L3), ozone, water vapor (WV), and temperature anomalies associated with the relatively short spring atmospheric blocking event and anomalously prolonged summer block over European Russia (ER) in 2010 are analyzed. Within the domain of the blocking anticyclones, negative total column ozone (TCO) anomalies and positive total column water vapor (TCWV) anomalies reaching the values of −25 and −32 Dobson Units (DU) and 10 and 11 kg m−2 during the spring and summer blocks are observed, respectively. Conversely, within the regions adjacent to the anticyclones to the west and east, positive TCO anomalies (77 and 45 DU) and negative TCWV anomalies (−3 and −4 kg m−2) are found. These TCO and TCWV anomalies are conditioned by the regional atmospheric circulation associated with the strong omega-type blocking. The TCO deficit and TCWV surplus within the atmospheric blocking domain are explained primarily by the poleward advection of subtropical air with low TCO and high TCWV content and tropopause uplift. The TCO and TCWV anomalies are also associated with quasi-stationary Rossby wave trains that accompanied these blocking events. An analysis of the anomaly vertical structure shows that the marked TCO decrease is primarily due to the lower stratospheric ozone decrease, while the strong TCWV increase is mainly the result of an increase of lower tropospheric WV content. The possible role of photochemical ozone destruction in the lower stratosphere due to WV advection within the blocked regions is also discussed. Vertical profiles of the thermal anomalies during both atmospheric blocking events reveal dipole-like structures characterized by positive temperature anomalies in the troposphere and negative anomalies in the lower stratosphere.

Anomalously low total ozone levels over the northern Urals and Siberia in late January 2016

In late January 2016, over the northern Urals and Siberia, the total ozone amounts at the level of about 200 DU were recorded for the first time over the entire period of observations since 1970s, classified as ozone “mini-hole”. We analyzed the possible causes and factors responsible for the anomalously low total ozone levels during winter of 2016 as compared to a number of previous Arctic winters with severe ozone depletion. Dynamic factors are shown to play a dominating role in the occurrence of the ozone anomaly in late January 2016, and even more significant ozone anomalies in the Arctic are hypothesized to be likely in the future.

Influence of the Arctic Oscillation on the Vertical Distribution of Wintertime Ozone in the Stratosphere and Upper Troposphere over the Northern Hemisphere

The influence of the Arctic Oscillation (AO) on the vertical distribution of stratospheric ozone in the Northern Hemisphere in winter is analyzed using observations and an offline chemical transport model. Positive ozone anomalies are found at low latitudes (0°–30°N) and there are three negative anomaly centers in the northern mid- and high latitudes during positive AO phases. The negative anomalies are located in the Arctic middle stratosphere (~30 hPa; 70°–90°N), Arctic upper troposphere–lower stratosphere (UTLS; 150–300 hPa, 70°–90°N), and midlatitude UTLS (70–300 hPa, 30°–60°N). Further analysis shows that anomalous dynamical transport related to AO variability primarily controls these ozone changes. During positive AO events, positive ozone anomalies between 0° and 30°N at 50–150 hPa are related to the weakened meridional transport of the Brewer–Dobson circulation (BDC) and enhanced eddy transport. The negative ozone anomalies in the Arctic middle stratosphere are also caused by the weakened BDC, while the negative ozone anomalies in the Arctic UTLS are caused by the increased tropopause height, weakened BDC vertical transport, weaker exchange between the midlatitudes and the Arctic, and enhanced ozone depletion via heterogeneous chemistry. The negative ozone anomalies in the midlatitude UTLS are mainly due to enhanced eddy transport from the midlatitudes to the latitudes equatorward of 30°N, while the transport of ozone-poor air from the Arctic to the midlatitudes makes a minor contribution. Interpreting AO-related variability of stratospheric ozone, especially in the UTLS, would be helpful for the prediction of tropospheric ozone variability caused by the AO.

Regional responses of surface ozone in Europe to the location of high-latitude blocks and subtropical ridges

Abstract. This paper analyses for the first time the impact of high-latitude blocks and subtropical ridges on near-surface ozone (O3) in Europe during a 15-year period. For this purpose, a catalogue of blocks and ridges over the Euro–Atlantic region is used together with a gridded dataset of maximum daily 8 h running average ozone (MDA8 O3) covering the period 1998–2012. The response of ozone to the location of blocks and ridges with centres in three longitudinal sectors (Atlantic, ATL, 30–0° W; European, EUR, 0–30° E; Russian, RUS, 30–60° E) is examined. The impact of blocks on ozone is regionally and seasonally dependent. In particular, blocks within the EUR sector yield positive ozone anomalies of ∼ 5–10 ppb over large parts of central Europe in spring and northern Europe in summer. Over 20 and 30 % of the days with blocks in that sector register exceedances of the 90th percentile of the seasonal ozone distribution at many European locations during spring and summer, respectively. The impacts of ridges during those seasons are subtle and more sensitive to their specific location, although they can trigger ozone anomalies above 10 ppb in northern Italy and the surrounding countries in summer, eventually exceeding European air quality (AQ) targets. During winter, surface ozone in the north-west of Europe presents completely opposite responses to blocks and ridges. The anticyclonic circulation associated with winter EUR blocking, and to a lesser extent with ATL blocking, yields negative ozone anomalies between −5 and −10 ppb over the UK, northern France and the Benelux. Conversely, the enhanced zonal flow around 50–60° N during the occurrence of ATL ridges favours the arrival of background air masses from the Atlantic and the ventilation of the boundary layer, producing positive ozone anomalies of ∼ 5 ppb in an area spanning from the British Isles to the northern half of Germany. We also show that multiple linear models on the seasonal frequency of occurrence of these synoptic patterns can explain a considerable fraction of the interannual variability in some winter and summer ozone statistics (mean levels and number of exceedances of the 90th percentile) over some regions of western Europe. Thus, this work provides the first quantitative assessments of the remarkable but distinct impacts that the anticyclonic circulation and the diversion of the zonal flow associated with blocks and ridges exert on surface ozone in Europe. The findings reported here can be exploited in the future to evaluate the modelled responses of ozone to circulation changes within chemical transport models (CTMs) and chemistry–climate models (CCMs).

Observed connections of Arctic stratospheric ozone extremes to Northern Hemisphere surface climate

We present observational evidence for linkages between extreme Arctic stratospheric ozone anomalies in March and Northern Hemisphere tropospheric climate in spring (March–April). Springs characterized by low Arctic ozone anomalies in March are associated with a stronger, colder polar vortex and circulation anomalies consistent with the positive polarity of the Northern Annular Mode/North Atlantic Oscillation in March and April. The associated spring tropospheric circulation anomalies indicate a poleward shift of zonal winds at 500 hPa over the North Atlantic. Furthermore, correlations between March Arctic ozone and March–April surface temperatures reveal certain regions where a surprisingly large fraction of the interannual variability in spring surface temperatures is associated with interannual variability in ozone. We also find that years with low March Arctic ozone in the stratosphere display surface maximum daily temperatures in March–April that are colder than normal over southeastern Europe and southern Asia, but warmer than normal over northern Asia, adding to the warming from increasing well-mixed greenhouse gases in those locations. The results shown here do not establish causality, but nevertheless suggest that March stratospheric ozone is a useful indicator of spring averaged (March–April) tropospheric climate in certain Northern Hemispheric regions.

Influence of enhanced Asian NO&amp;lt;sub&amp;gt;&amp;lt;i&amp;gt;x&amp;lt;/i&amp;gt;&amp;lt;/sub&amp;gt; emissions on ozone in the upper troposphere and lower stratosphere in chemistry–climate model simulations

Abstract. The Asian summer monsoon (ASM) anticyclone is the most pronounced circulation pattern in the upper troposphere and lower stratosphere (UTLS) during northern hemispheric summer. ASM convection plays an important role in efficient vertical transport from the surface to the upper-level anticyclone. In this paper we investigate the potential impact of enhanced anthropogenic nitrogen oxide (NOx) emissions on the distribution of ozone in the UTLS using the fully coupled aerosol–chemistry–climate model, ECHAM5-HAMMOZ. Ozone in the UTLS is influenced both by the convective uplift of ozone precursors and by the uplift of enhanced-NOx-induced tropospheric ozone anomalies. We performed anthropogenic NOx emission sensitivity experiments over India and China. In these simulations, covering the years 2000–2010, anthropogenic NOx emissions have been increased by 38 % over India and by 73 % over China with respect to the emission base year 2000. These emission increases are comparable to the observed linear trends of 3.8 % per year over India and 7.3 % per year over China during the period 2000 to 2010. Enhanced NOx emissions over India by 38 % and China by 73 % increase the ozone radiative forcing in the ASM anticyclone (15–40° N, 60–120° E) by 16.3 and 78.5 mW m−2 respectively. These elevated NOx emissions produce significant warming over the Tibetan Plateau and increase precipitation over India due to a strengthening of the monsoon Hadley circulation. However, increase in NOx emissions over India by 73 % (similar to the observed increase over China) results in large ozone production over the Indo-Gangetic Plain and Tibetan Plateau. The higher ozone concentrations, in turn, induce a reversed monsoon Hadley circulation and negative precipitation anomalies over India. The associated subsidence suppresses vertical transport of NOx and ozone into the ASM anticyclone.

An upper-branch Brewer–Dobson circulation index for attribution of stratospheric variability and improved ozone and temperature trend analysis

Abstract. We find that wintertime temperature anomalies near 4 hPa and 50° N/S are related, through dynamics, to anomalies in ozone and temperature, particularly in the tropical stratosphere but also throughout the upper stratosphere and mesosphere. These mid-latitude anomalies occur on timescales of up to a month, and are related to changes in wave forcing. A change in the meridional Brewer–Dobson circulation extends from the middle stratosphere into the mesosphere and forms a temperature-change quadrupole from Equator to pole. We develop a dynamical index based on detrended, deseasonalised mid-latitude temperature. When employed in multiple linear regression, this index can account for up to 60 % of the total variability of temperature, peaking at ∼ 5 hPa and dropping to 0 at ∼ 50 and ∼ 0.5 hPa, respectively, and increasing again into the mesosphere. Ozone similarly sees up to an additional 50 % of variability accounted for, with a slightly higher maximum and strong altitude dependence, with zero improvement found at 10 hPa. Further, the uncertainty on all equatorial multiple-linear regression coefficients can be reduced by up to 35 and 20 % in temperature and ozone, respectively, and so this index is an important tool for quantifying current and future ozone recovery.

Causes and factors of positive surface ozone anomalies in the Moscow region and on the southeastern coast of the Crimea

Ozone sources and factors responsible for anomalous surface ozone concentrations are discussed. Foreign observations and measurements of surface ozone in Moscow, nearby suburbs, and on the territory far removed from the megalopolis, as well as on the coast of the Black Sea, are used as an example to illustrate the interrelations between elevated surface ozone concentrations, air temperature, and transport speed in the planetary boundary layer, and to show the dependence on advection of ozone and its precursors. Studies of factors responsible for ozone episodes and causes of decreased ozone concentrations under meteorological conditions favorable for photochemical ozone production are the basis for interpretation and correction of model ozone predictions.

Zonally resolved impact of ENSO on the stratospheric circulation and water vapor entry values

AbstractBased on simulations with the Chemical Lagrangian Model of the Stratosphere (CLaMS) for the period 1979–2013, with model transport driven by the ECMWF ERA‐Interim reanalysis, we discuss the impact of the El Niño Southern Oscillation (ENSO) on the variability of the dynamics, water vapor, ozone, and mean age of air (AoA) in the tropical lower stratosphere during boreal winter. Our zonally resolved analysis at the 390 K potential temperature level reveals that not only (deseasonalized) ENSO‐related temperature anomalies are confined to the tropical Pacific (180–300°E) but also anomalous wave propagation and breaking, as quantified in terms of the Eliassen‐Palm (EP) flux divergence, with strongest local contribution during the La Niña phase. This anomaly is coherent with respective anomalies of water vapor (±0.5 ppmv) and ozone (±100 ppbv) derived from CLaMS being in excellent agreement with the Aura Microwave Limb Sounder observations. Thus, during El Niño a more zonally symmetric wave forcing drives a deep branch of the Brewer‐Dobson (BD) circulation. During La Niña this forcing increases at lower levels (≈390 K) over the tropical Pacific, likely influencing the shallow branch of the BD circulation. In agreement with previous studies, wet (dry) and young (old) tape recorder anomalies propagate upward in the subsequent months following El Niño (La Niña). Using CLaMS, these anomalies are found to be around +0.3 (−0.2) ppmv and −4 (+4) months for water vapor and AoA, respectively. The AoA ENSO anomaly is more strongly affected by the residual circulation (≈2/3) than by eddy mixing (≈1/3).

On the link between martian total ozone and potential vorticity

We demonstrate for the first time that total ozone in the martian atmosphere is highly correlated with the dynamical tracer, potential vorticity, under certain conditions. The degree of correlation is investigated using a Mars global circulation model including a photochemical model. Potential vorticity is the quantity of choice to explore the dynamical nature of polar vortices because it contains information on winds and temperature in a single scalar variable. The correlation is found to display a distinct seasonal variation, with a strong positive correlation in both northern and southern winter at poleward latitudes in the northern and southern hemisphere respectively.The identified strong correlation implies variations in polar total ozone during winter are predominantly controlled by dynamical processes in these spatio-temporal regions. The weak correlation in northern and southern summer is due to the dominance of photochemical reactions resulting from extended exposure to sunlight. The total ozone/potential vorticity correlation is slightly weaker in southern winter due to topographical variations and the preference for ozone to accumulate in Hellas basin. In northern winter, total ozone can be used to track the polar vortex edge.The ozone/potential vorticity ratio is calculated for both northern and southern winter on Mars for the first time. Using the strong correlation in total ozone and potential vorticity in northern winter inside the polar vortex, it is shown that potential vorticity can be used as a proxy to deduce the distribution of total ozone where satellites cannot observe for the majority of northern winter. Where total ozone observations are available on the fringes of northern winter at poleward latitudes, the strong relationship of total ozone and potential vorticity implies that total ozone anomalies in the surf zone of the northern polar vortex can potentially be used to determine the origin of potential vorticity filaments.

The natural oscillations in stratospheric ozone observed by the GROMOS microwave radiometer at the NDACC station Bern

Abstract. A multilinear parametric regression analysis was performed to assess the seasonal and interannual variations of stratospheric ozone profiles from the GROMOS (GROund-based Millimeter-wave Ozone Spectrometer) microwave radiometer at Bern, Switzerland (46.95° N, 7.44° E; 577 m). GROMOS takes part in the Network for the Detection of Atmospheric Composition Change (NDACC). The study covers the stratosphere from 50 to 0.5 hPa (from 21 to 53 km) and extends over the period from January 1997 to January 2015. The natural variability was fitted during the regression analysis through the annual and semi-annual oscillations (AO, SAO), the quasi-biennial oscillation (QBO), the El Niño–Southern Oscillation (ENSO) and the solar activity cycle. Seasonal ozone variations mainly appear as an annual cycle in the middle and upper stratosphere and a semi-annual cycle in the upper stratosphere. Regarding the interannual variations, they are primarily present in the lower and middle stratosphere. In the lower and middle stratosphere, ozone variations are controlled predominantly by transport processes, due to the long lifetime of ozone, whereas in the upper stratosphere its lifetime is relatively short and ozone is controlled mainly by photochemistry. The present study shows agreement in the observed naturally induced ozone signatures with other studies. Further, we present an overview of the possible causes of the effects observed in stratospheric ozone due to natural oscillations at a northern midlatitude station. For instance regarding the SAO, we find that polar winter stratopause warmings contribute to the strength of this oscillation since these temperature enhancements lead to a reduction in upper stratospheric ozone. We have detected a strong peak amplitude of about 5 % for the solar cycle in lower stratospheric ozone for our 1.5 cycles of solar activity. Though the 11-year ozone oscillation above Bern is in phase with the solar cycle, we suppose that the strong amplitude is partly due to meteorological disturbances and associated ozone anomalies in the Northern Hemisphere. Further, our observational study gave the result that ozone above Bern is anti-correlated with the ENSO phenomenon in the lower stratosphere and correlated in the middle stratosphere.

On the role of the eruption of the Merapi volcano in an anomalous total ozone decrease over Tomsk in April 2011

In April 2011, at Northern Hemisphere midlatitudes, a long-term anomalous decrease in the total ozone content was recorded over a number of regions, attributed to echoes of a large-scale Arctic ozone anomaly, observed in March. We showed that stratospheric ozone destruction over Tomsk during that period was caused by an eruption of Indonesian volcano Merapi in November, 2010. The NOAA HYSPLIT model was used to analyze air mass transport in the lower stratosphere starting from coordinates of volcanic emission from the date of eruption until late April. It was found that air masses, containing volcanic aerosol, came to the Northern Hemisphere midlatitudes in late March, 2011, in agreement with high aerosol content recorded in the stratosphere over Tomsk during that period. Based on analysis of temperature and ozone anomalies in the stratosphere over Tomsk, these anomalies were shown to be due to the presence of volcanic soot in aerosol composition.

The influence of Middle Range Energy Electrons on atmospheric chemistry and regional climate

We investigate the influence of Middle Range Energy Electrons (MEE; typically 30-300keV) precipitation on the atmosphere using the SOCOL3-MPIOM chemistry-climate model with coupled ocean. Model simulations cover the 2002-2010 period for which ionization rates from the AIMOS dataset and atmospheric composition observations from MIPAS are available. Results show that during geomagnetically active periods MEE significantly increase the amount of NOy and HOx in the polar winter mesosphere, in addition to other particles and sources, resulting in local ozone decreases of up to 35%. These changes are followed by an intensification of the polar night jet, as well as mesospheric warming and stratospheric cooling. The contribution of MEE also substantially enhances the difference in the ozone anomalies between geomagnetically active and quiet periods. Comparison with MIPAS NOy observations indicates that the additional source of NOy from MEE improves the model results, however substantial underestimation above 50km remains and requires better treatment of the NOy source from the thermosphere. A surface air temperature response is detected in several regions, with the most pronounced warming occurring in the Antarctic during austral winter. Surface warming of up to 2K is also seen over continental Asia during boreal winter.

Influence of wave activity on the composition of the polar stratosphere

The planetary wave impact on the polar vortex stability, polar stratosphere temperature, and content of ozone and other gases was simulated with the global chemical–climatic model of the lower and middle atmosphere. It was found that the planetary waves propagating from the troposphere into the stratosphere differently affect the gas content of the Arctic and Antarctic stratosphere. In the Arctic region, the degree of wave activity critically affects the polar vortex formation, the appearance of polar stratospheric clouds, the halogen activation on their surface, and ozone anomaly formation. Ozone anomalies in the Arctic region as a rule are not formed at high wave activity and can be registered at low activity. In the Antarctic Regions, wave activity affects the stability of polar vortex and the depth of ozone holes, which are formed at almost any wave activity, and the minimal ozone values depend on the strong or weak wave activity that is registered in specific years.

Причины и факторы положительных аномалий приземной концентрации озона в Московском регионе и на юго-восточном побережье Крыма

Причины и факторы положительных аномалий приземной концентрации озона в Московском регионе и на юго-восточном побережье Крыма