Zonal wave numbers 1-5 in planetary waves from the TOMS total ozone at 65° S

International audiencePlanetary waves in the total ozone at the southern latitude of 65° S are studied to obtain the main characteristics of the zonal wave numbers 1?5. The TOMS total ozone data were used to analyze the amplitude and periodicity variations of the five spectral components during August-December of 1979?2003. A presence of the shorter period of waves 1?3 in 1996 (7 days) in comparison with 2002 (8?12 days) is revealed which can be attributed to the distinction in conditions of typical and anomalously weak stratospheric polar vortex, probably, a strong and weak mean zonal wind. The interannual variations of the monthly and 5-month mean amplitudes of the zonal wave numbers 1?5 are described. Wave 1 has the largest amplitude in October (up to 139 DU in 2000) and increasing amplitude trend (15 DU/decade for October 1979?2003). The 5-month mean amplitudes averaged over 1979?2003 are 53.6, 29.9, 15.5, 10.5, and 7.8 DU for the wave number sequence 1, 2, 3, 4 and 5, respectively. For the stationary components the amplitudes are 38.3, 4.8, 1.8, 1.2, 0.7 DU, respectively. Thus, the stationary component of wave 1 and the traveling one of waves 2?5 are predominant. The tendencies in a long-term change in the wave number amplitude can be explained by taking into account the degree of wave deformation of the stratospheric polar vortex edge, net meridional displacements of the lower stratosphere air, and the difference between the total ozone loss and negative trends in the polar and mid-latitude regions. Keywords. General circulation ? Middle atmosphere dynamics ? Waves and tide

Quasi-stationary planetary waves in late winter Antarctic stratosphere temperature as a possible indicator of spring total ozone

Stratospheric preconditions for the annual Antarctic ozone hole are analyzed using the amplitude of quasi-stationary planetary waves in temperature as a predictor of total ozone column behaviour. It is found that the quasi-stationary wave amplitude in August is highly correlated with September–November total ozone over Antarctica with correlation coefficient (r) as high as 0.83 indicating that quasi-stationary wave effects in late winter have a persisting influence on the evolution of the ozone hole during the following three months. Correlation maxima are found in both the lower and middle stratosphere. These likely result from the influence of wave activity on ozone depletion due to chemical processes, and ozone accumulation due to large-scale ozone transport, respectively. Both correlation maxima indicate that spring total ozone tends to increase in the case of amplified activity of quasi-stationary waves in late winter. Since the stationary wave number one dominates the planetary waves that propagate into the Antarctic stratosphere in late austral winter, it is largely responsible for the stationary zonal asymmetry of the ozone hole relative to the South Pole. Processes associated with zonally asymmetric ozone and temperature which possibly contribute to differences in the persistence and location of the correlation maxima are discussed.V. O. Kravchenko, O. M. Evtushevsky, A. V. Grytsai, A. R. Klekociuk, G. P. Milinevsky, and Z. I. Grytsa

Preliminary comparison of the direct aerosol radiative forcing over Ukraine and Antarctic AERONET sites

Objectives. To analyze data on aerosol optical thickness (AOT) in the atmosphere over some Ukraine and Antarctic AERONET (AErosol RObotic NETwork) sites. To determine and compare direct aerosol radiative forcing (DRF) typical values using the data from midlatitude and Antarctic AERONET sites.Мета. Проаналізувати дані щодо аерозольної оптичної товщини (АОТ) в атмосфері на деяких пунктах мережі AERONET (AErosol RObotic NETwork) в Україні та Антарктиці. Для визначення та порівняння типових значень аерозольного прямого радіаційного форсингу (ПРФ) використати типові дані середньоширотної та двох антарктичних пунктів AERONET

Evolution of the eastward shift in the quasi-stationary minimum of the Antarctic total ozone column

The quasi-stationary pattern of the Antarctic total ozone has changed during the last 4 decades, showing an eastward shift in the zonal ozone minimum. In this work, the association between the longitudinal shift of the zonal ozone minimum and changes in meteorological fields in austral spring (September–November) for 1979–2014 is analyzed using ERA-Interim and NCEP–NCAR reanalyses. Regressive, correlative and anomaly composite analyses are applied to reanalysis data. Patterns of the Southern Annular Mode and quasi-stationary zonal waves 1 and 3 in the meteorological fields show relationships with interannual variability in the longitude of the zonal ozone minimum. On decadal timescales, consistent longitudinal shifts of the zonal ozone minimum and zonal wave 3 pattern in the middle-troposphere temperature at the southern midlatitudes are shown. Attribution runs of the chemistry–climate version of the Australian Community Climate and Earth System Simulator (ACCESS-CCM) model suggest that long-term shifts of the zonal ozone minimum are separately contributed by changes in ozone-depleting substances and greenhouse gases. As is known, Antarctic ozone depletion in spring is strongly projected on the Southern Annular Mode in summer and impacts summertime surface climate across the Southern Hemisphere. The results of this study suggest that changes in zonal ozone asymmetry accompanying ozone depletion could be associated with regional climate changes in the Southern Hemisphere in spring

Model of the propagation of very low-frequency beams in the Earth–ionosphere waveguide: principles of the tensor impedance method in multi-layered gyrotropic waveguides

The modeling of very low-frequency (VLF) electromagnetic (EM) beam propagation in the Earth–ionosphere waveguide (WGEI) is considered. A new tensor impedance method for modeling the propagation of electromagnetic beams in a multi-layered and inhomogeneous waveguide is presented. The waveguide is assumed to possess the gyrotropy and inhomogeneity with a thick cover layer placed above the waveguide. The influence of geomagnetic field inclination and carrier beam frequency on the characteristics of the polarization transformation in the Earth–ionosphere waveguide is determined. The new method for modeling the propagation of electromagnetic beams allows us to study the (i) propagation of the very low-frequency modes in the Earth–ionosphere waveguide and, in perspective, their excitation by the typical Earth–ionosphere waveguide sources, such as radio wave transmitters and lightning discharges, and (ii) leakage of Earth–ionosphere waveguide waves into the upper ionosphere and magnetosphere. The proposed approach can be applied to the variety of problems related to the analysis of the propagation of electromagnetic waves in layered gyrotropic and anisotropic active media in a wide frequency range, e.g., from the Earth–ionosphere waveguide to the optical waveband, for artificial signal propagation such as metamaterial microwave or optical waveguides

The data processing and analysis methods for stratospheric ozone and planetary wave study

We describe the methods and data sources for investigating the stratospheric ozone and planetary waves in the atmosphere in the framework of research provided by our international team. Selected ground-based and satellite instruments for ozone measurements and related reanalyses are described. Examples of data and analysis tools are shown. The technique of planetary wave spectral analysis under conditions of dynamic changes during sudden stratospheric warmings is presented. A brief description of the main results, obtained with the participation of the authors, using combined methods of analysis are considered. We describe procedures for the investigation of a long-term eastward displacement of the zonal ozone minimum over the Antarctic in the spring months, analysis of the spatial and temporal characteristics of the teleconnection between the tropical thermal source and the Antarctic stratosphere, and the creation of the predictive index used for the forecast of possible ozone hole anomalous development in spring months. Examples of application of analysis methods to retrieve the changes in the zonal asymmetry of the Arctic stratopause and features of the annual ozone cycle in connection with zonal ozone asymmetry are discussed

Winter 2018 major sudden stratospheric warming impact on midlatitude mesosphere from microwave radiometer measurements

Published: 14 August 2019. Includes Supplement as supporting information.The impact of a major sudden stratospheric warming (SSW) in the Arctic in February 2018 on the midlatitude mesosphere is investigated by performing the microwave radiometer measurements of carbon monoxide (CO) and zonal wind above Kharkiv, Ukraine (50.0∘ N, 36.3∘ E). The mesospheric peculiarities of this SSW event were observed using a recently designed and installed microwave radiometer in eastern Europe for the first time. Data from the ERA-Interim and MERRA-2 reanalyses, as well as the Aura microwave limb sounder measurements, are also used. Microwave observations of the daily CO profiles in January–March 2018 allowed for the retrieval of mesospheric zonal wind at 70–85 km (below the winter mesopause) over the Kharkiv site. Reversal of the mesospheric westerly from about 10 m s⁻¹ to an easterly wind of about −10 m s⁻¹ around 10 February was observed. The local microwave observations at our Northern Hemisphere (NH) midlatitude site combined with reanalysis data show wide-ranging daily variability in CO, zonal wind, and temperature in the mesosphere and stratosphere during the SSW of 2018. The observed local CO variability can be explained mainly by horizontal air mass redistribution due to planetary wave activity. Replacement of the CO-rich polar vortex air by CO-poor air of the surrounding area led to a significant mesospheric CO decrease over the station during the SSW and fragmentation of the vortex over the station at the SSW start caused enhanced stratospheric CO at about 30 km. The results of microwave measurements of CO and zonal wind in the midlatitude mesosphere at 70–85 km altitudes, which still are not adequately covered by ground-based observations, are useful for improving our understanding of the SSW impacts in this region.Yuke Wang, Valerii Shulga, Gennadi Milinevsky, Aleksey Patoka, Oleksandr Evtushevsky, Andrew Klekociuk, Wei Han, Asen Grytsai, Dmitry Shulga, Valery Myshenko, and Oleksandr Antyufeye