scholarly journals Estonian total ozone climatology

2002 ◽  
Vol 20 (2) ◽  
pp. 247-255 ◽  
Author(s):  
K. Eerme ◽  
U. Veismann ◽  
R. Koppel
Keyword(s):  
Total Ozone ◽  
Middle Atmosphere ◽  
Power Spectra ◽  
Ground Level ◽  
Atmospheric Composition ◽  
Trend Detection ◽  
Phase Lag ◽  
Quasi Biennial Oscillation ◽  
Significance Level ◽  
The One

Abstract. The climatological characteristics of total ozone over Estonia based on the Total Ozone Mapping Spectrometer (TOMS) data are discussed. The mean annual cycle during 1979–2000 for the site at 58.3° N and 26.5° E is compiled. The available ground-level data interpolated before TOMS, have been used for trend detection. During the last two decades, the quasi-biennial oscillation (QBO) corrected systematic decrease of total ozone from February–April was 3 ± 2.6% per decade. Before 1980, a spring decrease was not detectable. No decreasing trend was found in either the late autumn ozone minimum or in the summer total ozone. The QBO related signal in the spring total ozone has an amplitude of ± 20 DU and phase lag of 20 months. Between 1987–1992, the lagged covariance between the Singapore wind and the studied total ozone was weak. The spring (April–May) and summer (June–August) total ozone have the best correlation (coefficient 0.7) in the yearly cycle. The correlation between the May and August total ozone is higher than the one between the other summer months. Seasonal power spectra of the total ozone variance show preferred periods with an over 95% significance level. Since 1986, during the winter/spring, the contribution period of 32 days prevails instead of the earlier dominating 26 days. The spectral densities of the periods from 4 days to 2 weeks exhibit high interannual variability.Key words. Atmospheric composition and structure (middle atmosphere – composition and chemistry; volcanic effects) – Meteorology and atmospheric dynamics (climatology)

scholarly journals Surface ultraviolet radiation over east Siberia: seasonal variations

2002 ◽  
Vol 20 (4) ◽  
pp. 559-564
Author(s):  
A. V. Mikhalev ◽  
M. A. Chernigovskaya ◽  
A. Yu. Shalin ◽  
E. S. Kazimirovsky
Keyword(s):  
Ultraviolet Radiation ◽  
Uv Radiation ◽  
Middle Atmosphere ◽  
Ground Level ◽  
Atmospheric Composition ◽  
Time Interval ◽  
East Siberia ◽  
Solar Ultraviolet Radiation ◽  
Composition And Structure ◽  
Asymmetric Behaviour

Abstract. The results of spectral measurements of the daily near-noon surface direct solar ultraviolet radiation in the wavelength range of 295–345 nm obtained in Irkutsk (East Siberia) for the time interval of 1998–2000 are presented. For the period under consideration, the seasonal UV radiation variations are analysed that are associated with the total ozone dynamics, the transition of cyclonic and anticyclonic (Siberian anticyclone) periods, the presence of snow cover, and other factors. The analysis reveals an asymmetric behaviour of the seasonal course in ground-level UV radiation around the time of the summer solstice, with seasonal variation dependence on the wavelength. We have determined the irregular variations of surface UV radiation that is typical for the region, with their properties dependent on the season and on the spectral range analysed. The similarity of the above noted features from year to year was revealed.Key words. Atmospheric composition and structure (Transmission and scattering of radiation; instruments and techniques) – Meteorology and atmospheric dynamics (middle atmosphere dynamics)

scholarly journals Interannual variation patterns of total ozone and temperature in observations and model simulations

2005 ◽  
Vol 5 (5) ◽  
pp. 9207-9248 ◽  
Author(s):  
W. Steinbrecht ◽  
B. Haßler ◽  
C. Brühl ◽  
M. Dameris ◽  
M. A. Giorgetta ◽  
...  
Keyword(s):  
Solar Cycle ◽  
Total Ozone ◽  
Climate Model ◽  
Middle Atmosphere ◽  
Linear Regression Analysis ◽  
Volcanic Eruptions ◽  
Interannual Variations ◽  
Quasi Biennial Oscillation ◽  
Model Simulations ◽  
Stratospheric Temperature

Abstract. We report results from a multiple linear regression analysis of long-term total ozone observations (1979 to 2002, by TOMS/SBUV), of temperature reanalyses (1958 to 2002, NCEP), and of two chemistry-climate model simulations (1960 to 1999, by ECHAM4.L39(DLR)/CHEM (=E39/C), and MAECHAM4-CHEM). The model runs are transient experiments, where observed sea surface temperatures, increasing source gas concentrations (CO2, CFCs, CH4, N2O, NOx), 11-year solar cycle, volcanic aerosols and the quasi-biennial oscillation (QBO) are all accounted for. MAECHAM4-CHEM covers the atmosphere from the surface up to 0.01 hPa (≈80 km). For a proper representation of middle atmosphere (MA) dynamics, it includes a parametrization for momentum deposition by dissipating gravity wave spectra. E39/C, on the other hand, has its top layer centered at 10 hPa (≈30 km). It is targeted on processes near the tropopause, and has more levels in this region. Both models reproduce the observed amplitudes and much of the observed low-latitude patterns of the various modes of interannual variability, MAECHAM4-CHEM somewhat better than E39/C. Total ozone and lower stratospheric temperature show similar patterns. Main contributions to the interannual variations of total ozone and lower stratospheric temperature at 50 hPa come from a linear trend (up to −30 Dobson Units (DU) per decade, or −1.5 K/decade), the QBO (up to 25 DU, or 2.5 K peak to peak), the intensity of the polar vortices (up to 50 DU, or 5 K peak to peak), and from tropospheric weather (up to 30 DU, or 3 K peak to peak). Smaller variations are related to the 11-year solar cycle (generally less than 25 DU, or 2.5 K), and to ENSO (up to 15 DU, or 1.5 K). Volcanic eruptions have resulted in sporadic changes (up to −40 DU, or +3 K). Most stratospheric variations are connected to the troposphere, both in observations and simulations. At low latitudes, patterns are zonally symmetric. At higher latitudes, however, strong, zonally non-symmetric signals are found close to the Aleutian Islands or south of Australia. Such asymmetric features appear in the model runs as well, but often at different longitudes than in the observations. The results point to a key role of the zonally asymmetric Aleutian (or Australian) stratospheric anti-cyclones for interannual variations at high- latitudes, and for coupling between polar vortex strength, QBO, 11-year solar cycle and ENSO.

scholarly journals The role of dynamics in total ozone deviations from their long-term mean over the Northern Hemisphere

1999 ◽  
Vol 17 (2) ◽  
pp. 231-241 ◽  
Author(s):  
K. Petzoldt
Keyword(s):  
Correlation Coefficient ◽  
Northern Hemisphere ◽  
Total Ozone ◽  
Middle Atmosphere ◽  
Linear Trend ◽  
Atmospheric Composition ◽  
Data Set ◽  
Significant Linear Trend ◽  
Circulation Parameters

Abstract. Total ozone anomalies (deviation from the long-term mean) are created by anomalous circulation patterns. The dynamically produced ozone anomalies can be estimated from known circulation parameters in the layer between the tropopause and the middle stratosphere by means of statistics. Satellite observations of ozone anomalies can be compared with those expected from dynamics. Residual negative anomalies may be due to chemical ozone destruction. The statistics are derived from a 14 year data set of TOMS (Total Ozone Mapping Spectrometer January 1979-Dec. 1992) and corresponding 300 hPa geopotential (for the tropopause height) together with 30 hPa temperature (for stratospheric waves) at 60°N. The correlation coefficient for the linear multiple regression between total ozone (dependent variable) and the dynamical parameters (independent variables) is 0.88 for the zonal deviations in the winter of the Northern Hemisphere. Zonal means are also significantly dependent on circulation parameters, besides showing the known negative trend function of total ozone observed by TOMS. The significant linear trend for 60°N is \\sim3 DU/year in the winter months taking into account the dependence on the dynamics between the tropopause region and the mid-stratosphere. The highest correlation coefficient for the monthly mean total ozone anomalies is reached in November with 0.94.Key words. Atmospheric composition and structure (middle atmosphere · composition and chemistry) · Meteorology and atmospheric dynamics (middle atmosphere dynamics).

scholarly journals Validation of GOME total ozone by means of the Norwegian ozone monitoring network

1999 ◽  
Vol 17 (3) ◽  
pp. 430-436 ◽  
Author(s):  
G. Hansen ◽  
A. Dahlback ◽  
F. Tønnessen ◽  
T. Svenøe
Keyword(s):  
Total Ozone ◽  
Middle Atmosphere ◽  
Monitoring Network ◽  
High Arctic ◽  
Atmospheric Composition ◽  
Pixel Size ◽  
Composition And Structure ◽  
Instruments And Techniques ◽  
Ozone Monitoring ◽  
Good Agreement

Abstract. The Global Ozone Monitoring Experiment (GOME) onboard the ERS-2 satellite has been in operation since July 1995. The Norwegian ground-based total ozone network has played an important role both in the main validation during the commissioning phase and in the validation of upgraded versions of the analysis algorithms of the instrument. The ground-based network consists of various spectrometer types (Dobson, Brewer, UV filter instruments). The validation of the second algorithm version used until January 1998 reveals a very good agreement between GOME and ground-based data at solar zenith angles <60° and deviations of GOME total ozone data from ground-based data of up to ±60 DU (~20%) at zenith angles >60°. The deviations strongly depend on the season of the year, being negative in summer and positive in winter/spring, The deviations furthermore show a considerable scattering (up to ±25 DU in monthly average values of 5° SZA intervals), even in close spatial and temporal coincidence with ground-based measurements, especially in the high Arctic. The deviations are also dependent on the viewing geometry/ground pixel size with an additional negative offset for the large pixels used in the backswath mode and at solar zenith angles >85°, compared to forward-swath pixels.Key words. Atmospheric composition and structure (middle atmosphere · composition and chemistry; instruments and techniques)

scholarly journals The atmospheric chemistry general circulation model ECHAM5/MESSy1: consistent simulation of ozone from the surface to the mesosphere

2006 ◽  
Vol 6 (4) ◽  
pp. 6957-7050 ◽  
Author(s):  
P. Jöckel ◽  
H. Tost ◽  
A. Pozzer ◽  
C. Brühl ◽  
J. Buchholz ◽  
...  
Keyword(s):  
General Circulation Model ◽  
Atmospheric Chemistry ◽  
General Circulation ◽  
Middle Atmosphere ◽  
Circulation Model ◽  
Tropospheric Chemistry ◽  
Atmospheric Composition ◽  
Quasi Biennial Oscillation ◽  
Wave Forcing ◽  
Characteristic Features

Abstract. The new Modular Earth Submodel System (MESSy) describes atmospheric chemistry and meteorological processes in a modular framework, following strict coding standards. It has been coupled to the ECHAM5 general circulation model, which has been slightly modified for this purpose. A 90-layer model version up to 0.01 hPa was used at T42 resolution (~2.8 latitude and longitude) to simulate the lower and middle atmosphere. The model meteorology has been tested to check the influence of the changes to ECHAM5 and the radiation interactions with the new representation of atmospheric composition. A Newtonian relaxation technique was applied in the tropospheric part of the domain to weakly nudge the model towards the analysed meteorology during the period 1998–2005. It is shown that the tropospheric wave forcing of the stratosphere in the model suffices to reproduce the Quasi-Biennial Oscillation and major stratospheric warming events leading e.g. to the vortex split over Antarctica in 2002. Characteristic features such as dehydration and denitrification caused by the sedimentation of polar stratospheric cloud particles and ozone depletion during winter and spring are simulated accurately, although ozone loss in the lower polar stratosphere is slightly underestimated. The model realistically simulates stratosphere-troposphere exchange processes as indicated by comparisons with satellite and in situ measurements. The evaluation of tropospheric chemistry presented here focuses on the distributions of ozone, hydroxyl radicals, carbon monoxide and reactive nitrogen compounds. In spite of minor shortcomings, mostly related to the relatively coarse T42 resolution and the neglect of interannual changes in biomass burning emissions, the main characteristics of the trace gas distributions are generally reproduced well. The MESSy submodels and the ECHAM5/MESSy1 model output are available through the internet on request.

scholarly journals The atmospheric chemistry general circulation model ECHAM5/MESSy1: consistent simulation of ozone from the surface to the mesosphere

2006 ◽  
Vol 6 (12) ◽  
pp. 5067-5104 ◽  
Author(s):  
P. Jöckel ◽  
H. Tost ◽  
A. Pozzer ◽  
C. Brühl ◽  
J. Buchholz ◽  
...  
Keyword(s):  
General Circulation Model ◽  
Atmospheric Chemistry ◽  
General Circulation ◽  
Middle Atmosphere ◽  
Circulation Model ◽  
Tropospheric Chemistry ◽  
Atmospheric Composition ◽  
Direct Evaluation ◽  
Quasi Biennial Oscillation

Abstract. The new Modular Earth Submodel System (MESSy) describes atmospheric chemistry and meteorological processes in a modular framework, following strict coding standards. It has been coupled to the ECHAM5 general circulation model, which has been slightly modified for this purpose. A 90-layer model setup up to 0.01 hPa was used at spectral T42 resolution to simulate the lower and middle atmosphere. With the high vertical resolution the model simulates the Quasi-Biennial Oscillation. The model meteorology has been tested to check the influence of the changes to ECHAM5 and the radiation interactions with the new representation of atmospheric composition. In the simulations presented here a Newtonian relaxation technique was applied in the tropospheric part of the domain to weakly nudge the model towards the analysed meteorology during the period 1998–2005. This allows an efficient and direct evaluation with satellite and in-situ data. It is shown that the tropospheric wave forcing of the stratosphere in the model suffices to reproduce major stratospheric warming events leading e.g. to the vortex split over Antarctica in 2002. Characteristic features such as dehydration and denitrification caused by the sedimentation of polar stratospheric cloud particles and ozone depletion during winter and spring are simulated well, although ozone loss in the lower polar stratosphere is slightly underestimated. The model realistically simulates stratosphere-troposphere exchange processes as indicated by comparisons with satellite and in situ measurements. The evaluation of tropospheric chemistry presented here focuses on the distributions of ozone, hydroxyl radicals, carbon monoxide and reactive nitrogen compounds. In spite of minor shortcomings, mostly related to the relatively coarse T42 resolution and the neglect of inter-annual changes in biomass burning emissions, the main characteristics of the trace gas distributions are generally reproduced well. The MESSy submodels and the ECHAM5/MESSy1 model output are available through the internet on request.

scholarly journals Late spring ultraviolet levels over the United Kingdom and the link to ozone

1999 ◽  
Vol 17 (9) ◽  
pp. 1199-1209 ◽  
Author(s):  
J. Austin ◽  
C. M. H. Driscoll ◽  
S. F. G. Farmer ◽  
M. J. Molyneux
Keyword(s):  
Total Ozone ◽  
Middle Atmosphere ◽  
Atmospheric Dynamics ◽  
Atmospheric Composition ◽  
Radiative Processes ◽  
The United Kingdom ◽  
Chemical Effects ◽  
Composition And Structure ◽  
Time Of Year ◽  
First Time

Abstract. Erythemally-weighted ultraviolet (UVery) levels measured over southern England, during anticyclonic weather between 30 April and 2 May, 1997, were almost 50 higher than normally expected for clear skies and were similar to mid-summer values for the first time since measurements began in 1990. Investigation of this episode suggests that a combination of both meteorological and chemical effects were responsible for generating record low ozone amounts for the time of year. Further, comparisons between the A band ultraviolet (315 to 400 nm wavelength) amounts, and radiative calculations confirm that the high UVery was primarily due to the reduction in total ozone. These results are contrasted with a similar period for 1998, in which near climatological ozone amounts were measured. The prospects for enhanced UVery levels in future years are briefly reviewed in the light of expected increases in stratospheric halogen levels and greenhouse gases.Key words. Atmospheric composition and structure (middle atmosphere · composition and chemistry) · Meterology and atmospheric dynamics (middle atmosphere dynamics; radiative processes)

scholarly journals Total ozone decrease in the Arctic after REP events

2000 ◽  
Vol 18 (3) ◽  
pp. 332-336 ◽  
Author(s):  
V. C. Roldugin ◽  
M. I. Beloglazov ◽  
G. F. Remenets
Keyword(s):  
Total Ozone ◽  
Middle Atmosphere ◽  
Atmospheric Composition ◽  
The Arctic ◽  
Composition And Structure ◽  
Longitudinal Sector ◽  
The Mean ◽  
Polar Meteorology ◽  
The Difference ◽  
Daily Total

Abstract. Eight periods of relativistic electron precipitation (REP) with electron energies of more than 300 keV are identified from VLF data (10-14 kHz) monitored along the Aldra (Norway) - Apatity (Kola peninsula) radio trace. In these cases, anomalous ionization below 55-50 km occurred without disturbing the higher layers of the ionosphere. The daily total ozone values in Murmansk for six days before and six days after the REP events are compared. In seven of eight events a decrease in the total ozone of about 20 DU is observed. In one event of 25 March, 1986, the mean total ozone value for six days before the REP is bigger than that for six days after, but this a case of an extremely high ozone increase (144 DU during the six days). However, on days 3 and 4 there was a minimum of about 47 DU with regard to REP days, so this case also confirms the concept of the ozone decrease after REP. The difference between mean ozone values for periods six days before and six days after the REPs was found also for 23 points in Arctic on TOMS data. The difference was negative only in Murmansk longitudinal sector. Along the meridian of the trace it was negative at high latitudes in both hemispheres and was near zero at low latitudes.Key words: Atmospheric composition and structure (middle atmosphere - composition and chemistry) - Meteorology and atmospheric dynamics (polar meteorology)

scholarly journals Metrology of ground-based satellite validation: co-location mismatch and smoothing issues of total ozone comparisons

2015 ◽  
Vol 8 (8) ◽  
pp. 8023-8082 ◽  
Author(s):  
T. Verhoelst ◽  
J. Granville ◽  
F. Hendrick ◽  
U. Köhler ◽  
C. Lerot ◽  
...  
Keyword(s):  
Satellite Data ◽  
Total Ozone ◽  
Scattered Light ◽  
Polar Vortex ◽  
Atmospheric Composition ◽  
Individual Measurement ◽  
Error Budget ◽  
Comparison Results ◽  
Measurement Uncertainties ◽  
The One

Abstract. Comparisons with ground-based correlative measurements constitute a key component in the validation of satellite data on atmospheric composition. The error budget of these comparisons contains not only the measurement uncertainties but also several terms related to differences in sampling and smoothing of the inhomogeneous and variable atmospheric field. A versatile system for Observing System Simulation Experiments (OSSEs), named OSSSMOSE, is used here to quantify these terms. Based on the application of pragmatic observation operators onto high-resolution atmospheric fields, it allows a simulation of each individual measurement, and consequently also of the differences to be expected from spatial and temporal field variations between both measurements making up a comparison pair. As a topical case study, the system is used to evaluate the error budget of total ozone column (TOC) comparisons between on the one hand GOME-type direct fitting (GODFITv3) satellite retrievals from GOME/ERS2, SCIAMACHY/Envisat, and GOME-2/MetOp-A, and on the other hand direct-sun and zenith-sky reference measurements such as from Dobsons, Brewers, and zenith scattered light (ZSL-)DOAS instruments respectively. In particular, the focus is placed on the GODFITv3 reprocessed GOME-2A data record vs. the ground-based instruments contributing to the Network for the Detection of Atmospheric Composition Change (NDACC). The simulations are found to reproduce the actual measurements almost to within the measurement uncertainties, confirming that the OSSE approach and its technical implementation are appropriate. This work reveals that many features of the comparison spread and median difference can be understood as due to metrological differences, even when using strict co-location criteria. In particular, sampling difference errors exceed measurement uncertainties regularly at most mid- and high-latitude stations, with values up to 10 % and more in extreme cases. Smoothing difference errors only play a role in the comparisons with ZSL-DOAS instruments at high latitudes, especially in the presence of a polar vortex. At tropical latitudes, where TOC variability is lower, both types of errors remain below about 1 % and consequently do not contribute significantly to the comparison error budget. The detailed analysis of the comparison results, including now the metrological errors, suggests that the published random measurement uncertainties for GODFITv3 reprocessed satellite data are potentially overestimated, and adjustments are proposed here. This successful application of the OSSSMOSE sytem to close for the first time the error budget of TOC comparisons, bodes well for potential future applications, which are briefly touched upon.

scholarly journals Case study of mesospheric front dissipation observed over the northeast of Brazil

2018 ◽  
Vol 36 (2) ◽  
pp. 311-319 ◽  
Author(s):  
Amauri Fragoso Medeiros ◽  
Igo Paulino ◽  
Cristiano Max Wrasse ◽  
Joaquim Fechine ◽  
Hisao Takahashi ◽  
...  
Keyword(s):  
Middle Atmosphere ◽  
Vertical Wind Shear ◽  
The Other ◽  
Atmospheric Composition ◽  
Meteor Radar ◽  
Composition And Structure ◽  
Waves And Tides ◽  
Wind Profiles ◽  
The One

Abstract. On 3 October 2005 a mesospheric front was observed over São João do Cariri (7.4∘ S, 36.5∘ W). This front propagated to the northeast and appeared in the airglow images on the west side of the observatory. By about 1.5 h later, it dissipated completely when the front crossed the local zenith. Ahead of the front, several ripple structures appeared during the dissipative process of the front. Using coincident temperature profile from the TIMED/SABER satellite and wind profiles from a meteor radar at São João do Cariri, the background of the atmosphere was investigated in detail. On the one hand, it was noted that a strong vertical wind shear in the propagation direction of the front produced by a semidiunal thermal tide was mainly responsible for the formation of duct (Doppler duct), in which the front propagated up to the zenith of the images. On the other hand, the evolution of the Richardson number as well as the appearance of ripples ahead of the main front suggested that a presence of instability in the airglow layer that did not allow the propagation of the front to the other side of the local zenith. Keywords. Atmospheric composition and structure (airglow and aurora) – meteorology and atmospheric dynamics (middle atmosphere dynamics; waves and tides)

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