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  • × Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA, USA
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来源:Atmospheric Chemistry and Physics

作者:M. Pastel;J. Anderson;H. J. Wang;等

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The trends and variability of ozone are assessed over a northernmid-latitude station, Haute-Provence Observatory(OHP: 43.93° N, 5.71° E), using total column ozoneobservations from the Dobson and Système d'Analyse par ObservationZénithale spectrometers, and stratospheric ozone profilemeasurements from light detection and ranging (lidar), ozonesondes,Stratospheric Aerosol and Gas Experiment (SAGE) II, Halogen OccultationExperiment (HALOE) and Aura Microwave Limb Sounder (MLS). A multivariate regressionmodel with quasi-biennial oscillation (QBO), solar flux, aerosoloptical thickness, heat flux, North Atlantic Oscillation (NAO) and apiecewise linear trend (PWLT) or equivalent effective stratosphericchlorine (EESC) functions is applied to the ozone anomalies. Themaximum variability of ozone in winter/spring is explained by QBO andheat flux in the ranges 15–45 km and 15–24 km,respectively. The NAO shows maximum influence in the lowerstratosphere during winter, while the solar flux influence is largestin the lower and middle stratosphere in summer. The total column ozonetrends estimated from the PWLT and EESC functions are of−1.47 ± 0.27 and −1.40 ± 0.25 DU yr−1, respectively,over the period 1984–1996 and about 0.55 ± 0.30 and0.42 ± 0.08 DU yr−1, respectively, over the period 1997–2010. Theozone profiles yield similar and significant EESC-based and PWLT trends for 1984–1996, and are about −0.5 and−0.8% yr−1 in the lower and upper stratosphere,respectively. For 1997–2010, the EESC-based and PWLT estimates are of the order of 0.3 and 0.1% yr−1,respectively, in the 18–28 km range, and at 40–45 km,EESC provides significant ozone trends larger than the insignificantPWLT results. Furthermore, very similar vertical trends for therespective time periods are also deduced from another long-termsatellite-based data set (GOZCARDS–Global OZone Chemistry And Relatedtrace gas Data records for the Stratosphere) sampled at northernmid-latitudes. Therefore, this analysis unveils ozone recovery signalsfrom total column ozone and profile measurements at OHP, and hence inthe northern mid-latitudes.

    来源:Atmospheric Chemistry and Physics

    作者:J. Notholt;T. Warneke;J. T. Randerson;等

    使用许可:署名(BY)

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    来源:Atmospheric Chemistry and Physics

    作者:J. X. Warner;G. Pfister;S. Massie;等

    使用许可:署名(BY)

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    来源:Atmospheric Chemistry and Physics

    作者:S. Wang;K. A. Walker;T. von Clarmann;等

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    The diurnal variation ofHOCl and therelated species ClO,HO2and HCl measured by satellites has been compared with the results ofa one-dimensional photochemicalmodel. The studycompares the datafrom variouslimb-viewinginstruments with modelsimulations fromthemiddle stratosphereto the lower mesosphere. Data from threesub-millimetre instruments andtwo infrared spectrometers are used,namely fromthe Sub-Millimetre Radiometer (SMR)on board Odin, theMicrowave Limb Sounder (MLS)on board Aura, the Superconducting Submillimeter-wave Limb-Emission Sounder(SMILES) on theInternational Space Station, the Michelson InterferometerforPassiveAtmosphericSounding (MIPAS) onboard ENVISAT, andtheAtmospheric ChemistryExperiment FourierTransformSpectrometer(ACE-FTS) on board SCISAT. Inter-comparison of the measurements frominstrumentson sun-synchronoussatellites(SMR,MLS, MIPAS)andmeasurements from solaroccultationinstruments(ACE-FTS)ischallenging since themeasurementscorrespond todifferentsolarzenith angles (or local times).However, using a model which coversallsolar zenith anglesand data from theSMILESinstrument whichmeasured at all localtimes overa period ofseveral months provides the possibility to verify the model andto indirectly compare the diurnallyvariablespecies. Thesatellitedata were averaged for latitudesof 20° S to20° N for theSMILES observation period fromNovember 2009to April2010and were compared at three altitudes: 35,45and55 km. Besides presenting the SMILES data, the study alsoshows a firstcomparison of the latest MLSdata (version 3.3) ofHOCl, ClO, and HO2with other satellite observations, aswellasa first evaluation ofHO2observations made by Odin/SMR.The MISU-1D model has beencarefully initialised andrun forconditions and locations of the observations. The diurnalcycle features for the species investigatedhere are generally well reproduced by the model. The satellite observations and the model agree well in terms of absolute mixing ratios.The differences between the day and night values of the modelare in good agreement with the observations although the amplitude ofthe HO2 diurnal variation is 10–20% lower in the model than in theobservations. In particular, the data offered theopportunity to study the reaction ClO+HO2 → HOCl+O2in the lower mesosphere at 55 km.At this altitude the HOCl night-timevariation depends only on this reaction. The result of this analysispoints towards a value of the rate constant within the range of the JPL 2006recommendation and the upper uncertainty limit of the JPL 2011 recommendation at 55 km.

      来源:Atmospheric Chemistry and Physics

      作者:D. Youn;D. J. Wuebbles;S. C. Olsen;等

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      The continuing increase in demand for commercial aviation transport raisesquestions about the effects of resulting emissions on the environment. Thepurpose of this study is to investigate, using a global chemistry transportmodel, to what extent aviation emissions outside the boundary layer influenceair quality in the boundary layer. The large-scale effects of current levelsof aircraft emissions were studied through comparison of multiple simulationsallowing for the separated effects of aviation emissions occurring in thelow, middle and upper troposphere. We show that emissions near cruisealtitudes (9–11 km in altitude) rather than emissions during landingand take-off are responsible for most of the total odd-nitrogen (NOy), ozone (O3) and aerosol perturbations near the ground with anoticeable seasonal difference. Overall, the perturbations of these speciesare smaller than 1 ppb even in winter when the perturbations aregreater than in summer. Based on the widely used air quality standards anduncertainty of state-of-the-art models, we conclude that aviation-inducedperturbations have a negligible effect on air quality even in areas withheavy air traffic. Aviation emissions lead to a less than 1% aerosolenhancement in the boundary layer due to a slight increase in ammoniumnitrate (NH4NO3) during cold seasons and a statisticallyinsignificant aerosol perturbation in summer. In addition, statisticalanalysis using probability density functions, Hellinger distance, andp value indicate that aviation emissions outside the boundary layer do notaffect the occurrence of extremely high aerosol concentrations in theboundary layer. An additional sensitivity simulation assuming the doubling ofsurface ammonia emissions demonstrates that the aviation induced aerosolincrease near the ground is highly dependent on background ammoniaconcentrations whose current range of uncertainty is large.

        来源:Atmospheric Chemistry and Physics

        作者:D. Youn;D. J. Wuebbles;S. C. Olsen;等

        使用许可:署名(BY)

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