[en] A method is described for the analysis of the natural ¹⁴CO concentration in the atmosphere. It is based on the separation of CO from ambient air, followed by the determination of its ¹⁴C-content by proportional gas counting employing a low volume counter. The method is described in detail. The concentration of ¹⁴CO at midlatitudes (51⁰N) exhibits a marked seasonal variation with a winter maximum of 25 +- 2 molecules/cm³ and a minimum of 11 +- 1 molecules/cm³ during summer. Measurements at different latitudes show a decrease of the ¹⁴CO concentration from the pole to the equator. Interpretations of the data are based on calculations with a 2-d-time dependent model. From the simultaneous examination of the ¹⁴CO and ¹²CO balance in the troposphere it is possible to derive the two most important parameters for the global cycle of atmospheric CO: the concentration of OH radicals in the troposphere - and thus the lifetime of CO - and the contribution of biological sources to the CO budget. From this work the concentration of OH radicals in the troposphere is estimated to average around 6.5 x 10⁵ molecules/cm³, biological sources are shown to contribute about 12.5 x 10¹⁴g ¹²CO per year to the CO budget. (orig.)

[en] Using state-of-the-art models from the Coupled Model Intercomparison Project Phases 5 and 6 (CMIP5/6), future changes of sudden stratospheric warming (SSW) events under a moderate emission scenario (RCP45/SSP245) and a strong emissions scenario (RCP85/SSP585) are evaluated with respect to the historical simulations. Changes in four characteristics of SSWs are examined in 54 models: the SSW frequency, the seasonal distribution, stratosphere–troposphere coupling, and the persistency of the distorted or displaced polar vortex. The composite results show that none of these four aspects will change robustly. An insignificant (though positive) change in the SSW frequency from historical simulations to RCP45/SSP245 and then to RCP85/SSP585 is consistently projected by CMIP5 and CMIP6 multimodel ensembles in most wintertime months (December–March). This increase in the SSW frequency is most pronounced in mid- (late-) winter in CMIP6 (CMIP5). No shift in the seasonality of SSWs is simulated especially in the CMIP6 future scenarios. Both the reanalysis and CMIP5/6 historical simulations exhibit strong stratosphere–troposphere coupling during SSWs, and the coupling strength is nearly unchanged in the future scenario simulations. The near surface responds immediately after the onset of SSWs in both historical and future scenarios experiments, denoted by the deep downward propagation of zonal-mean easterly anomalies from the stratosphere to the troposphere. On average, the composite circumpolar easterly winds persist for 8 d in the reanalysis and CMIP5/6 historical experiments, which are projected to remain unchanged in both the moderate and strong emissions scenarios, implying the lifecycle of SSWs will not change. (letter)

[en] A brief introduction is given on how the ozone layer formed and about the factors depleted ozone layer such as chloro bromo compounds and so on; then, it follows the processes which destroy the troposphere. The damaging effect of ultraviolet radiation is described. Finally,the action taken to reduce the depletion of ozone layer is presented

[en] Complete text of publication follows. As was recently found, the atmospheric boundary layer comprises aeroelectric structures manifested in short-period electric-field pulsations (with period from several to several hundred seconds). The formation of aeroelectric structures is most rapid under conditions of intensive convection. The sizes of such structures are determined by characteristic variation scales of aerodynamic and electrodynamic parameters of the atmosphere (including the surface-layer height and the atmospheric 'electrode' layer scale) as well as heating inhomogeneities of the ground (water) surface. Formed as a result of convective processes or capture of positive and negative charged particles (both ions and aerosols) by convective cells, aeroelectric structures move in an air flow along the Earth's surface. Since the further evolution of convective cells results, in particular, in cloud formation relationship between such convective cells of the atmosphere and the aeroelectric-structure evolvement leads to the assumption that charge separation and accumulation processes are characteristic of even early stages of cloud formation. Obviously, development of the methods of diagnostics and modeling of aeroelectric structures is important for a study of both convective and electric processes in the lower troposphere. The test-structure method developed in this paper is aimed, first of all, at solution of the mentioned problems. This paper is devoted to numerical modeling of the electric-field dynamics in the atmosphere by the test-structure method. The method of diagnostics of aeroelectric-structure (AES) parameters based on measurement of short-period electric-field fluctuations is proposed and implemented. Thunderstorm applications of the test-structure method based on the local experimental data is considered. Aerosol influence on relaxation time of AES is investigated.

[en] Complete text of publication follows. We present some observed effects of the equatorial QBO and the Sun on polar atmospheric dynamics. The analysis primarily uses data from mesospheric wind radars and ECMWF and NCEP reanalysis. The results demonstrate the importance of treating the atmosphere as a single connected system both vertically from the troposphere to the thermosphere, and horizontally from one pole to the other. Examples include the combined solar and QBO influence on (i) planetary wave propagation between the winter troposphere and summer polar mesosphere, (ii) the dynamics of the polar vortex in the Antarctic mesosphere, and (iii) the variability of major polar atmospheric modes.

[en] The solar-troposphere effect is discovered in the Southern Hemisphere as well as in the Northern one. At the fourth-fifth day after the entering of the Earth into the solar corpuscular streams, an increase of instability of the troposphere is observed in the moderate latitudes of the Southern Hemisphere. (The variance of the 24-hour pressure differences increases at 16% on the average). The assumption of its being accidental is rejected at the significance level of 0.2 per cent. But the hypothesis of the solar-troposphere effect being absent both in Southern Hemisphere and the Northern one is rejected at the significance level of 2x10^-6

[en] Complete text of publication follows. Differences in the external part of the vertical geomagnetic component point to the existence of local inhomogeneities in the magnetosphere or the ionosphere. The correlations between the new magnetic index η and the ionospheric characteristics - foE (E layer critical frequency) monthly median deviations - are analysed. The analysis was based on one-minute data recorded at each of 20 European Magnetic Observatories working in the INTERMAGNET network and from 18 ionosondes for 2004. The high peaks (2-2.7) of the new magnetic index correlate in time with large (+1.6 MHz and -1.1 MHz) punctual median deviations of foE. Such punctual deviations can suggest local inhomogeneities (vertical drifts) in the ionosphere. The correlation in space is not trivial. The strong peak of ? is situated on the map between the positive and negative deviations of foE. Additional observation is connected with correlation in time of the high ? value with the negative median deviations of h'F2 (in some cases up to -90 km). The increase of the electromagnetic activity can cause lightnings in troposphere. Ionospheric data are sparse in time and in space in opposite to the magnetic data. The map of the magnetic indices can suggest the behaviour of ionospheric characteristics in the areas where we have no data.

[en] Thishs monographic study presents the dynamics of hydrogen in t e Earth's atmosphere. Atomic hydrogen is produced in the homosphere through a complex system of chemical reaction in wich molecules of ₂, H₂O, C ₄ s ''parent '' molecules are involved. The maximum production of H appears at 8O km resulting a concentration of the order of 10⁸ cm^-3. There is a correlation between the total mixing ratio of hydrogen in the homosphere and the global escape flux from the Earth's atmosphere. Two new physical mechanisms which may have a substantial contribution to the total escape flux are presented: ''polar wind'' and charge exchange of H with ''hot'' protons. The possibilities of accretion of hydrogen, as atomic hydrogen or as water from the Earth's atmosphere, are analysed in brief. (authors)

[en] Complete text of publication follows. Powerful lightning flashes with large return stroke peak currents induce energetic and electrical coupling between the troposphere and the upper atmosphere via the quasi-electrostatic and/or the radiated electromagnetic pulse (EMP). Several researchers have suggested that the lightning EMP which drives ELVES may be a significant source of variation in the upper atmosphere at regional and global scales. In addition, 'big' lightning is more loosely associated with other Transient Luminous Events (TLEs) and are linked to Terrestrial Gamma-ray Flashes (TGFs). Global lightning provides context on the activity levels of thunderstorm systems, assisting studies into TLEs, TGFs, meteorology and atmospheric electricity in general. One of the few experiments which can currently provide such observations is the multi-station World Wide Lightning Location Network (WWLLN). The WWLLN-stations measure the very low frequency (VLF; 3-30 kHz) radiation from lightning discharges. Propagation at these very long electromagnetic wavelengths (up to 100 km) allows lightning strokes to be located in real time at up to 10,000 km from the receivers with a location accuracy that is estimated to be ∼10-20 km, and sometimes better than this. True global mapping of lightning from widely spaced (a few Mm) ground-based receivers requires the use of frequencies <30 kHz. Lightning impulses in this frequency range suffer low propagation attenuation, and hence propagation in the Earth-ionosphere waveguide is possible over global distances. In April 2009 we introduced a new algorithm for reprocessing WWLLN observations, leading to an increase in locations by a factor of 2.7. In this talk I hope to discuss our most recent efforts to produce new, smarter algorithms leading to DE improvements. I will also summarise the current state of the WWLLN, during a phase of significant station growth.

No abstract available