Showing papers on "Tropopause published in 1980"

Turbulent Mixing within Tropopause Folds as a Mechanism for the Exchange of Chemical Constituents between the Stratosphere and Troposphere

Abstract: Evidence is presented which illustrates the role of jet stream-frontal zone clear air turbulence (CAT) as a mechanism for the exchange of air and chemical trace constituents between the stratosphere and the troposphere. Three-dimensional air motion sensing instrumentation and fast-response ozone and condensation nuclei analysers on board research aircraft permit the quantitative evaluation of the turbulent flux of chemical constituents across the tropopause. The observations reveal that tropopause folds are mixing regions whose chemical characteristics lie somewhere in between those of the troposphere and the stratosphere. The temporal changes of ozone and condensation nuclei brought about through the vertical flux divergence of these quantities suggest that turbulent mixing processes are of first-order importance as a mechanism for stratospheric-tropospheric exchange in the vicinity of jet stream-frontal zone-associated topopause folds.

Stratospheric Sensitivity to Perturbations in Ozone and Carbon Dioxide: Radiative and Dynamical Response.

Abstract: We have attempted to assess the stratospheric effects of two different perturbations: 1) a uniform 50% reduction in ozone; and 2) a uniform doubling of carbon dioxide. The primary studies employ an annual mean insulation version of the recently developed GFDL 40-level general circulation model (GCM). Supporting auxiliary calculations using purely radiative models are also presented. One of these, in which the thermal sensitivity is computed using the assumption that heating by dynamical processes is unaffected by changed composition, gives results which generally are in excellent agreement with those from the GCM. Exceptions to this occur in the ozone reduction experiment at the tropical tropopause and the tropical mesosphere. The predicted response to the ozone reduction is largest at 50 km in the tropics, where the temperature decreases by 25 K; at the tropical tropopause, the decrease is 5 K. The carbon dioxide increase results in a 10 K decrease at 50 km, decreasing to zero at the tropopause....

Structure and dynamics of the stratosphere and mesosphere revealed by VHF radar investigations

Abstract: Powerful VHF radars are capable of almost continuously monitoring the threedimensional velocity vector and the distribution of turbulence in the middle atmosphere, i.e. the stratosphere and mesosphere. Methods of radar investigations of the middle atmosphere are outlined and the basic parameters, mean and fluctuating velocities as well as reflectivity and persistency of atmospheric structures, are defined. Results of radar investigations are described which show that the tropopause level as well as a criterion on the stability of the lower stratosphere can be deduced. Besides mean wind velocities, VHF radars can measure instantaneous velocities due to acoustic gravity waves. The interaction of gravity waves with the background wind is discussed, and it is shown that cumulus convection is an effective source of gravity waves in the lower stratosphere. The vertical microstructure of the stratosphere, manifesting itself in thin stratified sheets in which temperature steps occur, is investigated by applying knowledge from investigations of the oceanic thermocline. Possible origins, like shear generation and lateral convection of the microstructure of the stratosphere, are discussed. Observations of gravity waves in the mesosphere are reviewed and their connection with turbulence structures is pointed out. Finally, some open questions which could be answered by further VHF radar investigations are summarized.

Stratospheric CFCl3, CF2Cl2, and N2O height profile measurements at several latitudes

Abstract: The mixing ratios of CFCl3, CF2Cl2, and N2O have been measured as a function of altitude from 6 to 37 km above sea level by using a balloon-borne grab-sampling system. The 24 flights were made during the period July 1976 to March 1979 from Wyoming, Panama, Brazil, and Antarctica. These data are reported here both numerically and graphically, the latter being examined for latitudinal and temporal trends. A mean tropopause height for each location and date was used as the reference for the height profiles. The resulting set of CF2Cl2 and N2O profiles show a discernible dependence on latitude; the lapse rate of these mixing ratios is greater for the mid-latitudes when compared to the equatorial latitudes. The upper tropospheric portion of the CFCl3 and CF2Cl2 data show annual increases of 10.4±3.9 and 10.7±1.9%/yr, respectively, in the northern hemisphere for the middle of the measurement period (end of 1977). Furthermore, the limited number of southern hemispheric data for these constituents are about 8% lower than the northern hemispheric values but have a comparable annual increase. The corresponding N2O data show no interhemispheric differences and the possibility of only a slight increase (less than 2%/yr).

The distribution of beryllium‐7 in the troposphere: Implications on stratospheric/tropospheric air exchange

Abstract: The distribution of cosmogenic beryllium-7 (7Be) in the lower troposphere is described based on the analysis of long-term (1973-1979) ground level 7Be measurements. 7Be is used as a tracer of stratospheric air to suggest that the annual mean outflow of stratospheric air in the northern hemisphere can be 20 to 30% higher than in the southern hemisphere. This asymmetry is maximum during the northern hemisphere spring and reaches its peak in April. Over North America, the 7Be concentrations show a high positive correlation (linear coefficients of 0.8 to 0.9) with the occurrence of tropospheric low-pressure troughs over several latitude belts, thus supporting the postulate that tropopause folding events, associated with low-pressure troughs, are the dominant stratospheric/tropospheric (S/T) exchange mechanism. It is demonstrated that S/T air exchange shows a distinct seasonal variation that is highly dependent on the latitude. At midlatitudes (40-50°N) over North America, the S/T air exchange is maximum in summer; at low altitudes (20-30°N), it is maximum in winter and early spring. The study suggests a mechanistic model that can be used to characterize S/T air exchange at any geographical location using routinely available meteorological information.

A review of radar observations of turbulence in the lower stratosphere

Abstract: The use of high-power radars for the observation of air motions and the occurrence of turbulence in the vicinity of the tropopause is reviewed. A model is presented for the interpretation of radar observations from the thin turbulent layers which occur in the stable regions of the upper troposphere and lower stratosphere. Radar observations are shown to be potentially important for the study of the transport processes that operate between the troposphere and the stratosphere.

Vertical structure of the atmosphere of Venus from Pioneer Venus orbiter radio occultations

Abstract: Between December 1978 and February 1979 the Pioneer Venus orbiter spacecraft returned some 140 S band and X band radio occultation measurements of the Venus atmosphere. Results from 13 measurements, covering diverse latitudes from near equatorial to polar, are presented in this paper in the form of vertical profiles of temperature. The temperature profiles show a pronounced inversion at the tropopause for latitudes higher than about 50 deg, with the deepest inversions occurring between the latitudes of 60 deg and 70 deg, the latitudes at which the cold collar cloud feature was observed by the Pioneer Venus Vortex instrument. A comparison of the temperature profiles derived from radio occultation measurements with the stratospheric infrared temperature soundings of the Vortex instrument and the in situ measurements of tropospheric temperature and pressure by the North, Sounder, and Day probes indicates excellent agreement.

Regional Characteristics of the Northern Hemisphere Wintertime Circulation: A Comparison of the Simulation of a GFDL General Circulation Model with Observations

Abstract: The hemispheric distributions of a selected set of temporal mean, variance and covariance statistics produced by a general circulation model developed at the Geophysical Fluid Dynamics Laboratory are compared with observations. The fields presented include 1) the seasonally averaged 300 mb geopotential height and zonal wind speed, sea level pressure and 500 mb vertical velocity; 2) the root-mean-squares of 500 and 1000 mb heights, and of 850 mb temperature; 3) the correlation coefficient between the 1000 and 500 mb heights, and 4) the horizontal and vertical transports of heat by transient eddies in the lower troposphere, and the horizontal eddy transports of momentum and potential vorticity near the tropopause. The partitioning of the variance of 500 mb height according to fluctuations of different temporal and spatial scales is examined. By making use of time filters which retain fluctuations with periods between 2.5 and 6 days, the characteristics of synoptic-scale disturbances appearing in th...

The transport of minor atmospheric constituents between troposphere and stratosphere

Abstract: Measurements of the water vapour content of air in the upper troposphere and lower stratosphere are reviewed. They are interpreted to indicate that significant upward movement of air through a pressure level of about 100 mb, by processes of any scale, occurs only in equatorial latitudes, but they leave uncertain the mechanism of the upward transfer. This implies that contaminants emitted into the atmosphere below this level can reach the upper stratosphere only by way of the equatorial tropopause and after passage through precipitating cloud. The minimum hemispheric exchange of mass through this level is about 1017kg per year. The mass balance of several minor atmospheric constituents, naturally or artificially introduced in the surface layers or in the high stratosphere, is shown to be consistent with this minimum mass exchange.

Stratospheric source for unexpectedly large values of ozone measured over the Pacific Ocean during Gametag, August 1977

Abstract: Unexpectedly large ozone mixing ratios measured on the August 1977 Global Atmospheric Measurements Experiment of Tropospheric Aerosols and Gases (Gametag) flight from San Francisco, Calif., to Hilo, Hawaii, are first shown to be of stratospheric origin, then the most probable mode of transport is determined. Isentropic trajectories are traced backward in time from the observations to the boundaries of the stratosphere, close to the northern section of the Asiatic continent. A travel time of only 3 days via the large-scale waves is almost 100 times faster than that computed from the zonal-seasonal mean circulations. Also, the laminar structure of the ozone distribution is consistent with a folded tropopause.

Gravity Waves from Thunderstorms

Abstract: Gravity waves generated by severe thunderstorms in the eastern Ohio-Pennsylvania area were recorded by an array of microbarovariographs at Palisades, New York and by standard microbarographs across northeastern United States. The waves were associated with the cold mesohigh from the outflow of the thunderstorms. Along their path the waves apparently triggered new thunderstorms. The waves were observed to propagate with the velocity of the wind just below the tropopause. The long-distance propagation of the waves is explained by the presence of a dust associated with the critical level (steering level), in agreement with the derivations given by Lindzen and Tung (1976). The dust was directional and waves were absent to the west of the generating area. In the generating area wave-CISK might have been operating. Sharp vertical temperature gradients associated with the passage of the waves were observed by temperature sensors on a tower.

Observations of stable layers in the troposphere and stratosphere using VHF radar

Abstract: Observations of the Sunset radar located near Boulder, Colorado, reveal order of magnitude enhancements of the signals received on the vertically directed antenna over the signals received nearly simultaneously on the antennas directed off the vertical. These enhancements are caused by Fresnel reflection and Fresnel scattering from thin stable layers. They are most pronounced from stable regions of the atmosphere in the troposphere and stratosphere and especially from the lower stratosphere just above the tropopause. The ability to detect stable layers from enhanced echoes on VHF radars is applied to the determination of the tropopause. It is concluded that the height of the tropopause can be determined within a few hundred meters.

Measurement of the tropospheric and stratospheric SO2 distribution

Abstract: The knowledge of the SO/sub 2/ mixing ratio at the tropopause and in the lower stratosphere is necessary for understanding the formation and the existence of the stratospheric aerosol layer. A new chemiluminescence technique permitted the analysis of SO/sub 2/ below 1 ng SO/sub 2//ml reaction liquid. The filter-sampling technique enables a detection limit of (0.01 +- 0.001) parts per billion by volume (ppBv) SO/sub 2/. Comparisons with other methods were performed, and flight application problems are discussed. During 1977 and 1978, several aircraft ascents were performed, reaching up to 5.2 km into the stratosphere. In continental air masses the SO/sub 2/ mixing ratio decreases strongly within the first 5 km, while in maritime air masses a nearly constant mixing ratio with altitude was observed. A mean value of 0.5 ppBv seems to be typical for layers above 6 km, and SO/sub 2/ mixing ratios between 0.03 and 0.17 ppBv SO/sub 2/ were found at the tropopause level, increasing slightly above the tropopause. The experimental results were compared with one-dimensional model calculations.

Evidence for a solar cycle signal in tropospheric winds

Abstract: Amplitudes and phases of the 11-year solar cycle in wind speed and temperature at radiosonde levels have been determined. These results are based on 174 stations over the northern hemisphere for the 25-year data period 1949–1973. Amplitudes and phases were estimated by the method of time-lagged correlation with the quasi-periodic 10.7-cm solar radio flux. The largest atmospheric amplitudes are near the tropopause level during winter, where in several regions over 40% of the interannual variance of the wind speeds is explained by the solar cycle. The hemispheric patterns of amplitude and phase suggest that the year-to-year latitudinal oscillations of the jet stream and the amplitude of the major standing long waves both appear to vary with the solar cycle. It is suggested that these results are due to changes in ultraviolet radiation, causing changes in ozone, and thus in stratospheric temperature, height, and wind fields. These changes may influence long-wave vertical propagation characteristics and the direct radiation exchange between the stratosphere and troposphere. Possible problems with this hypothesis are discussed. To verify this hypothesis, the morphology of the solar cycle changes in stratospheric wind and temperature and the associated effect on tropospheric standing waves must be estimated. These results show that atmospheric responses to the solar cycle vary with longitude as well as with latitude. Hence studies of the atmospheric solar cycle must avoid arbitrarily combining stations over broad geographical areas or as zonal means.

Decrease in CO2 mixing ratio observed in the stratosphere

Abstract: Air samples, collected cryogenically at different heights of the stratosphere, were analysed for carbon dioxide with an IR absorption technique. Supplementary tropospheric air samples were taken aboard commercial airliners. The results reported here show that the CO2 mixing ratio is not constant with altitude but rather decreases in the stratosphere, by about 7 p.p.m.v., between the tropopause and 33 km. One conclusion is that recently increased concentrations of CO2 in the troposphere have not propagated far into the stratosphere.

Radar measurement of short-period atmospheric waves and related scattering properties at the altitude of 13–25 km over Jicamarca

Abstract: The sensitive Doppler radar (49.92 MHz) at Jicamarca (12.0°S, 76.9°W) is used to investigate short-period atmospheric waves at the altitudes of 13–25 km. The dominant short-period waves observed are largely buoyancy, or Brunt-Vaisala, oscillations, the periods of which are about 5 min in the lower stratosphere and about 11 min in the upper troposphere. The buoyancy oscillations are, on the average, convected with the mean horizontal wind. It is also confirmed that the partial reflection is relatively dominant in these altitudes compared with turbulent scatter. These features are not found around the tropopause, where a vertical shear of horizontal winds of the order of 5 m s−1 km−1 is observed.

Thermal structure of jupiter's atmosphere obtained by inversion of voyager 1 infrared measurements

Abstract: Data from the Voyager 1 infrared spectroscopy investigation have been used to retrieve temperature profiles in the atmosphere of Jupiter An analysis of information content indicates good vertical resolution with low measurement noise propagation in the Jovian troposphere and reduced resolution in the stratosphere Among the problems found in common with the sounding of the terrestrial atmosphere are limited tropopause definition and dependence on upper boundary constraints Preliminary results obtained by using a constrained linear algorithm and a filtered Chahine approach are presented

Vertical mass- and trace constituent transports in the vicinity of jet streams

Abstract: Detailed analyses of radiosonde and aircraft data were used to identify regions of stratospheric air incursions into the troposphere and of tropospheric air inflow into the stratosphere The latter flow phenomenon was associated with a distinct separation between potential vorticity tropopause and stability tropopause It occurred in the region of confluence between jet branches of different origin and was connected with strong anticyclonic shears which are associated with the presence of a wind maximum above the stability tropopause

Interaction between the troposphere and stratosphere

Abstract: Three aspects o f the interaction between troposphere and stratosphere are considered: (i) mass transports, (ii) radiative processes, (hi) dynamical effects. (i) T he transport o f constituents across the tropopause is a major feature in determining the detailed com position of the stratosphere since the principal sources and sinks of many of its chemical species are located in the troposphere or at the Earth ’s surface. The nature of this transfer by the mean circulations and smaller scale phenomena is described. (ii) Since the radiation balance throughout the atmosphere is affected by the composition at all levels, changes in radiatively important constituents in one atmospheric region may affect conditions in another. The possible importance of this mechanism in troposphere—stratosphere interaction is discussed. (hi) It is now well established that upward transfer of mechanical energy from the troposphere by planetary-w ave motions plays a major role in driving the general circulation o f the stratosphere. Recent studies clarifying some details of the processes involved are outlined. The possibility that the stratospheric circulation could significantly influence tropospheric motions is also briefly considered.

Linearized Tropopause Dynamics and Cyclone Development

Abstract: A preliminary investigation into the dynamical effects produced by the tropopause upon a mid-latitude wave cyclone is described. This article describes linear effects since the various structures of a fixed tropopause are examined. In general, the solutions are sensitive to changes in tropopause structure only when they have large amplitude in the tropopause vicinity or the forcing for the problem is significantly altered by the tropopause structure. The forcing is greatest at the bottom boundary and interior tropopause interface. The basic current contains an internal jet. Many characteristic properties of this jet were found in a less sophisticated antecedent study where the velocity maximum occurred at the top boundary. This research forms the basis for future inquiry into nonlinear tropopause dynamics.

Measurements of N2O, CF2Cl2, CFCI3, CH3CCl3, CCl4, and CH3Cl in the troposphere and lower stratosphere over North Amrica.

Abstract: Samples of tropospheric and stratospheric air were collected on aircraft flights between October 4 and October 13, 1976. The region of the atmosphere surveyed was over the North American continent (approximately 18°N to 65°N latitude). Samples were obtained at heights ranging from about 3, 000ft. to 45, 000ft. Measurements of N2O, CF2Cl2, CFCl3, CH3CCl3, and CCl4 were made by GC/EC techniques, and of CH3Cl by GC/MS. The latitudinal and height profiles of these trace gases are reported in this paper. Calculations based on these measurements yield the following average tropospheric concentrations: [N2O]=(330±2) ppb v, [CF2Cl2]=(236±7) ppt v, [CFCl3]=(140±5) ppt v, [CH3CCl3]=(145±25) ppt v, and [CCl4]=(134±9) ppt v (where the ± values are the standard deviations). The N2O mixing ratio decreases only slightly in the lower stratosphere. CF2Cl2 and CFCl3 mixing ratios decrease by about 10% and 15% respectively, within 4km above the tropopause. CCl4 mixing ratio declines by about 50% within 4km above the tropopause. CH3CCl3 mixing ratios also show a sharp decline above the tropopause, similar to that of CCl4. CH3Cl on the other hand displays almost no change in mixing ratio between the free troposphere and the lower stratosphere.

Design of a ground-based remote sensing system using radio wavelengths to profile lower atmospheric winds, temperature, and humidity

Abstract: An essential requirement of a regional (mesoscale) observing and forecasting service is continuous monitoring of temperature, moisture, and winds. To meet these needs, the Wave Propagation Laboratory, NOAA, is constructing a six-channel microwave radiometer (two moisture channels and four temperature channels) and a UHF radar for wind profiling. The radar also aids in the retrieval of temperature profiles by measuring the altitude of significant features of the profile; e.g., the base of and elevated inversion, the height of a nocturnal inversion, or the height of the tropopause. Moisture, wind and temperature sounding capabilities are analyzed and results are presented of field experiments and of computer simulations. Retrieval algorithms to incorporate active and passive measurements are presented. Finally, improvement in profile retrieval using combined ground-based and satellite soundings is discussed .

Temperature and ozone variations in the stratosphere

Abstract: Examined are temperature and ozone variations in the Northern Hemisphere stratosphere during the period 1958–77, as estimated from radiosondes rocketsondes, ozonesondes, and Umkehr measurements. The temperature variation in the low tropical stratosphere is a combination of the variation associated with the quasi-biennial oscillation, and a variation nearly out of phase with the pronounced 3-yearly temperature oscillation (Southern Oscillation) present in the tropical troposphere since 1963. Based on radiosonde and rocketsonde data, the quasibiennial temperature oscillation can be traced as high as the stratopause, the phase varying with both height and latitude. However, the rocketsonde-derived temperature decrease of several degrees Celsius in the 25–55 km layer of the Western Hemisphere between 1969 (sunspot maximum) and 1976 (sunspot minimum) is not apparent in high-level radiosonde data, so that caution is advised with respect to a possible solar-terrestrial relation. There has been a strong quasi-biennial oscillation in ozone in the 8–16 km layer of the north polar region, with ozone minimum near the time of quasi-biennial west wind maximum at a height of 20 km in the tropics. A quasi-biennial oscillation in ozone (of similar phase) is also apparent from both ozonesonde data and Umkehr measurements in 8–16 and 16–24 km layers of north temperate latitudes, but not higher up. Both measurement techniques also suggest a slight overall ozone decrease in the same layers between 1969 and 1976, but no overall ozone change in the 24–32 km layer. Umkehr measurements indicate a significant 6–8% increase in ozone amount in all stratospheric layers between 1964 and 1970, and in 1977 the ozone amount in the 32–46 km layer was still 4% above average despite the predicted depletion due to fluorocarbon emissions. The decrease in ozone in the 32–46 km, layer of mid latitudes following the volcanic eruptions of Agung and Fuego is believed to be mostly fictitious and due to the bias introduced into the Umkehr technique by stratospheric aerosols of volcanic origin. Above-average water vapor amounts in the low stratosphere at Washington, DC, appear closely related to warm tropospheric temperatures in the tropics, presumably reflecting variations in strength of the Hadley circulation.

A New Tropopause Definition from Simultaneous Ozone-Temperature Profiles.

Abstract: : Historically, the tropopause has been defined arbitrarily in terms of particular features present in a temperature profile. This study suggests a modified definition which is consistent with the assumption that the tropopause is a boundary between the ozone rich air of the stratosphere and the ozone poor air of the troposphere. Several hundred simultaneous temperature and ozone profiles from the middle 1960s and the latter 1970s were examined in order to arrive at a tropopause definition based on temperature and yet consistent with the ozone evidence. These data span a wide range of latitudes and seasons. Agreement between the conventional World Meteorological Organization (WMO) defined tropopause based on temperature lapse rate, and a tropopause defined subjectively on the basis of ozone gradients was found to be only 68%. However, a modification of the WMO tropopause definition, which relaxed the thickness criterion and considered the relative change in lapse rate from troposphere to stratosphere, produced a 95% agreement with the subjective tropopause based on ozone. (Author)

Middle atmosphere dynamics and composition

Abstract: In this paper we have adopted the term “middle atmosphere” to describe that region of the earth’s atmosphere that lies above the tropopause but below an altitude of 100 km Looking at Fig 1, we see that the altitude extent of the middle atmosphere varies with latitude and season such that’, for example, the lower boundary of the middle atmosphere, the tropopause, is at about 17 km (about 80 mb) at the equator and at about 8 or 9 km at the pole (about 300 mb) Also, we see from this latitude-height temperature figure that other factors must be considered to explain the zonally-averaged temperature structure of the middle atmosphere beside radiative energy inputs For instance, we see that in both the winter and summer, the equatorial lower stratosphere temperatures are cooler than at middle latitudes and that mesopause temperatures are warmer during the darkness of winter than during the continual sunlight of summer We will see that the additional physics needed to explain these features involve the dynamics of the middle atmosphere

Volcanic Contributions to the Stratospheric Sulfate Layer

Abstract: We have detected the transport of volcanic sulfate through the tropical tropopause. This is particularly noteworthy because the source volcanic eruption was only of modest intensity and, therefore, not normally thought to be of stratospheric importance. Using lidar, the veil was detected on two days during January 1977. Although the bulk of the material was in the troposphere, there was evidence of transport through the tropopause on both days. Trajectory calculations suggested that the source was Nyiragongo volcano in central Africa (1.5°S, 29.2°E). The presence of an adiabatic temperature profile through the dust layer suggests that the volcanic layer was being convected by means of radiative absorption. This mechanism may provide sulfate for the maintenance of a background level of stratospheric sulfate. During the six years of lidar observations in Hawaii (19.5°N), we have rarely observed such layers. Visual, lidar and other observations of the volcanic cloud are presented.

Analytical Initialization for Three-Dimensional Numerical Models

Abstract: A technique for generating analytical initial conditions for three-dimensional numerical models is presented. The technique combines trigonometric and other mathematical functions with meteorological constraints to construct an idealized atmosphere which exhibits commonly observed “real” atmosphere structural characteristics. For example, pressure and thermal waves which slope with height, tropopause, low-level moist tongue, phase differences in pressure and thermal waves, and a jet maximum at the tropopause level are all generated by the simple system of equations. Examples of both mesoscale and synoptic-scale initial conditions are given, and results of integrating the mesoscale initial conditions in a three-dimensional model are shown. The initialization procedure is economical and flexible, and potential applications include testing weather modification sensitivity, finite-difference schemes, lateral boundary formulations, and various subgrid-scale parameterizations.

Balance of the tropospheric ozone and its relation to stratospheric intrusions indicated by cosmogenic radionuclides. Technical progress report, November 1, 1979-June 30, 1980

Abstract: The balance of the tropospheric ozone is investigated considering the ozone sources with emphasis on tropospheric pollutants and stratospheric-tropospheric exchange processes. The measuring series of ozone concentration from the years 1977-1979 obtained at three different levels of the boundary layer (700, 1800, and 3000 m a.s.l.) have been analyzed. the data have been evaluated in correlation with relevant meteorological parameters, for instance solar radiation. For the different levels various types of ozone sources must be assumed. At the mountain stations prevails influx of stratospheric ozone. In the valley, however, photochemical production must be regarded as main source. A systematic study of ozone profiles obtained by balloon sondes revealed that as a rule after solar flares associated with Forbush effect drastic changes of the ozone profile take place in the lower stratosphere. Then, extremely high maxima of the ozone partial pressure are observed immediately above the tropopause and also intensive influxes of tropospheric air into the stratosphere between 200 and 100 mb. Effects of a modified lidar system on measurements of stratospheric aerosol layers and necessary corrections in evaluating the backscatter profiles are discussed and most recent measuring rresults presented.