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The three-dimensional quantification of small scale processes in the upper troposphere and lower stratosphere is one of the challenges of current atmospheric research and requires the development of new measurement strategies. This work presents first results from the newly developed Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) obtained during the ESSenCe and TACTS/ESMVal aircraft campaigns. The focus of this work is on the so-called dynamics mode data characterized by a medium spectral and a very high spatial resolution. The retrieval strategy for the derivation of two- and three-dimensional constituent fields in the upper troposphere and lower stratosphere is presented. Uncertainties of the main retrieval targets (temperature, O3, HNO3 and CFC-12) and their spatial resolution are discussed. During ESSenCe, high resolution two-dimensional cross-sections have been obtained. Comparisons to collocated remote-sensing and in-situ data indicate a good agreement between the data sets. During TACTS/ESMVal a tomographic flight pattern to sense an intrusion of stratospheric air deep into the troposphere has been performed. This filament could be reconstructed with an unprecedented spatial resolution of better than 500 m vertically and 20 km × 20 km horizontally.
The three-dimensional quantification of small-scale processes in the upper troposphere and lower stratosphere is one of the challenges of current atmospheric research and requires the development of new measurement strategies. This work presents the first results from the newly developed Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) obtained during the ESSenCe (ESa Sounder Campaign) and TACTS/ESMVal (TACTS: Transport and composition in the upper troposphere/lowermost stratosphere, ESMVal: Earth System Model Validation) aircraft campaigns. The focus of this work is on the so-called dynamics-mode data characterized by a medium-spectral and a very-high-spatial resolution. The retrieval strategy for the derivation of two- and three-dimensional constituent fields in the upper troposphere and lower stratosphere is presented. Uncertainties of the main retrieval targets (temperature, O3, HNO3, and CFC-12) and their spatial resolution are discussed. During ESSenCe, high-resolution two-dimensional cross-sections have been obtained. Comparisons to collocated remote-sensing and in situ data indicate a good agreement between the data sets. During TACTS/ESMVal, a tomographic flight pattern to sense an intrusion of stratospheric air deep into the troposphere was performed. It was possible to reconstruct this filament at an unprecedented spatial resolution of better than 500 m vertically and 20 × 20 km horizontally.
Wenn alles (oder doch fast alles) ›Kultur‹ ist und Kulturwissenschaftler so eigentlich über alles (oder doch fast alles) Bescheid wissen müssten, ist die Qual der Wahl groß - selbst bei der (ohnehin unabdingbaren) Beschränkung auf Linklisten statt einzelner Seiten. Die vorliegende Bibliographie setzt sich zwei Ziele: Zum einen sollen die wichtigsten Web-Angebote zu Kulturwissenschaften/Cultural Studies erschlossen werden; zum anderen sollen über wenige, anerkannte ›Portalseiten‹ Wege zum Internetwissen über die für den Kulturwissenschaftler relevanten Disziplinen und Forschungsgebiete eröffnet werden. Wie schon bei den vorangehenden Teilen der Bibliographie bitten wir unsere Leser um Alternativ- und Ergänzungsvorschläge. Die Bibliographie wird auch auf unserer Homepage (www.kulturpoetik.de bzw. www.culturalpoetics.net) veröffentlicht, kann also von dort heruntergeladen und im eigenen Browser verwendet werden.
Die Bibliographie soll in die aktuelle Theorie-Diskussion um Kulturwissenschaft und kulturgeschichtliche Literaturwissenschaft einführen und deren wichtigste Paradigmen vorstellen. In der Auswahl wurden neuere und Überblicks-Darstellungen bevorzugt; Grundlagenwerke der methodischen Paradigmen werden nur im Ausnahmefall genannt; zur besseren Orientierung wurden bei Sammelbänden mitunter auch die Inhaltsverzeichnisse aufgelistet.
Das Forschungsgebiet von Teil B dieser Bibliographie ist noch kaum erschlossen – und wird auch in der kulturgeschichtlichen Literaturwissenschaft noch weitgehend ignoriert. Es umfasst Themen, Verfahren, Praktiken, Handlungsfelder, die in der ästhetischen und poetischen Diskussion seit jeher eine große Rolle gespielt haben, deren Geltungsbereich aber keineswegs auf Kunst und Literatur beschränkt ist. Begreift man sie als protoästhetische bzw. proto-poetische Elementarien der Kultur, als anthropologisch fundierte ›poetogene Strukturen‹ (Rüdiger Zymner), so wären sie Ursprungsorte des Poetischen und Ästhetischen, die historisch wie systematisch der Ausdifferenzierung eines eigengesetzlichen ästhetischen Systems vorausliegen. Auf jeden Fall aber handelt es sich um Schnittstellen, über die ›Kunst‹ und ›Nicht-Kunst‹ ständig miteinander interagieren; als solche sind sie für eine nach Funktion und Pragmatik des Ästhetischen fragende Kulturwissenschaft von zentralem Interesse. Für die Titelaufnahme gelten die gleichen Auswahlregeln wie für die bereits erschienenen Teile der Bibliographie: Zeitlicher Schwerpunkt ist das letzte Jahrzehnt. Aufsatzpublikationen wurden nur im Ausnahmefall berücksichtigt. Nicht aufgenommen wurden Untersuchungen, die auf bestimmte Autoren und/oder Werke begrenzt sind.
Der Willkür- und Zufallsfaktor bei Ermittlung, Auswahl und Anordnung der Einträge ist in diesem zweiten Teil der Bibliographie noch wesentlich höher als schon im ersten: Für kulturwissenschaftliche Arbeiten gibt es bisher weder klare Bestimmungsmerkmale noch eine etablierte Systematik; man erwarte also weder materielle noch systematische Vollständigkeit oder auch nur Repräsentativität. Wir haben Publikationen der jüngsten Vergangenheit zu kulturwissenschaftlichen Themen (also nicht notwendigerweise auch mit kulturwissenschaftlicher Fragestellung und Methode) gesammelt und lose thematisch/systematisch geordnet. Die so entstandene Literaturliste ist wenig mehr als ein erster, ergänzungsbedürftiger Versuch, die aktuellen Themenfelder der Kulturwissenschaft zu kartographieren.
Auch die im Teil 2.C gesammelten Titel stehen für ein bisher kaum reflektiertes Problemfeld: Welche Auswirkungen kann (oder vielleicht ja: muss) eine kulturgeschichtliche Orientierung für traditionelle Domänen der Literaturwissenschaft wie Literaturgeschichtsschreibung, Gattungstheorie und -geschichte oder, noch allgemeiner, für die Theorie und Geschichten von Kunstformen und Medien haben? Für die Titelaufnahme gelten die gleichen Auswahlregeln wie für die bereits erschienenen Teile der Bibliographie: Zeitlicher Schwerpunkt ist das letzte Jahrzehnt. Aufsatzpublikationen wurden nur im Ausnahmefall berücksichtigt. Nicht aufgenommen wurden Untersuchungen, die auf bestimmte Autoren und/oder Werke begrenzt sind.
Active chlorine species play a dominant role in the catalytic destruction of stratospheric ozone in the polar vortices during the late winter and early spring seasons. Recently, the correct understanding of the ClO dimer cycle was challenged by the release of new laboratory absorption cross sections (Pope et al., 2007) yielding significant model underestimates of observed ClO and ozone loss (von Hobe et al., 2007). Under this aspect, Arctic stratospheric limb emission measurements carried out by the balloon version of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS-B) from Kiruna (Sweden) on 11 January 2001 and 20/21 March 2003 have been reanalyzed with regard to the chlorine reservoir species ClONO2 and the active species, ClO and ClOOCl (Cl2O2). New laboratory measurements of IR absorption cross sections of ClOOCl for various temperatures and pressures allowed for the first time the retrieval of ClOOCl mixing ratios from remote sensing measurements. High values of active chlorine (ClOx) of roughly 2.3 ppbv at 20 km were observed by MIPAS-B in the cold mid-winter Arctic vortex on 11 January 2001. While nighttime ClOOCl shows enhanced values of nearly 1.1 ppbv at 20 km, ClONO2 mixing ratios are less than 0.1 ppbv at this altitude. In contrast, high ClONO2 mixing ratios of nearly 2.4 ppbv at 20 km have been observed in the late winter Arctic vortex on 20 March 2003. No significant ClOx amounts are detectable on this date since most of the active chlorine has already recovered to its main reservoir species ClONO2. The observed values of ClOx and ClONO2 are in line with the established chlorine chemistry. The thermal equilibrium constants between the dimer formation and its dissociation, as derived from the balloon measurements, are on the lower side of reported data and in good agreement with values recommended by von Hobe et al. (2007). Calculations with the ECHAM/MESSy Atmospheric Chemistry model (EMAC) using established kinetics show similar chlorine activation and deactivation, compared to the measurements in January 2001 and March 2003, respectively.
Active chlorine species play a dominant role in the catalytic destruction of stratospheric ozone in the polar vortices during the late winter and early spring seasons. Recently, the correct understanding of the ClO dimer cycle was challenged by the release of new laboratory absorption cross sections (Pope et al., 2007) yielding significant model underestimates of observed ClO and ozone loss (von Hobe et al., 2007). Under this aspect, nocturnal Arctic stratospheric limb emission measurements carried out by the balloon version of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS-B) from Kiruna (Sweden) on 11 January 2001 and 20/21 March 2003 have been reanalyzed with regard to the chlorine reservoir species ClONO2 and the active species, ClO and ClOOCl (Cl2O2). New laboratory measurements of IR absorption cross sections of ClOOCl for various temperatures and pressures allowed for the first time the retrieval of ClOOCl mixing ratios from remote sensing measurements. High values of active chlorine (ClOx) of roughly 2.3 ppbv at 20 km were observed by MIPAS-B in the cold mid-winter Arctic vortex on 11 January 2001. While nighttime ClOOCl shows enhanced values of nearly 1.1 ppbv at 20 km, ClONO2 mixing ratios are less than 0.1 ppbv at this altitude. In contrast, high ClONO2 mixing ratios of nearly 2.4 ppbv at 20 km have been observed in the late winter Arctic vortex on 20 March 2003. No significant ClOx amounts are detectable on this date since most of the active chlorine has already recovered to its main reservoir species ClONO2. The observed values of ClOx and ClONO2 are in line with the established polar chlorine chemistry. The thermal equilibrium constants between the dimer formation and its dissociation, as derived from the balloon measurements, are on the lower side of reported data and in good agreement with values recommended by von Hobe et al. (2007). Calculations with the ECHAM/MESSy Atmospheric Chemistry model (EMAC) using established kinetics show similar chlorine activation and deactivation, compared to the measurements in January 2001 and March 2003, respectively.
Mitteilungen
(2014)
Significant reductions in stratospheric ozone occur inside the polar vortices each spring when chlorine radicals produced by heterogeneous reactions on cold particle surfaces in winter destroy ozone mainly in two catalytic cycles, the ClO dimer cycle and the ClO/BrO cycle. Chlorofluorocarbons (CFCs), which are responsible for most of the chlorine currently present in the stratosphere, have been banned by the Montreal Protocol and its amendments, and the ozone layer is predicted to recover to 1980 levels within the next few decades. During the same period, however, climate change is expected to alter the temperature, circulation patterns and chemical composition in the stratosphere, and possible geo-engineering ventures to mitigate climate change may lead to additional changes. To realistically predict the response of the ozone layer to such influences requires the correct representation of all relevant processes. The European project RECONCILE has comprehensively addressed remaining questions in the context of polar ozone depletion, with the objective to quantify the rates of some of the most relevant, yet still uncertain physical and chemical processes. To this end RECONCILE used a broad approach of laboratory experiments, two field missions in the Arctic winter 2009/10 employing the high altitude research aircraft M55-Geophysica and an extensive match ozone sonde campaign, as well as microphysical and chemical transport modelling and data assimilation. Some of the main outcomes of RECONCILE are as follows: (1) vortex meteorology: the 2009/10 Arctic winter was unusually cold at stratospheric levels during the six-week period from mid-December 2009 until the end of January 2010, with reduced transport and mixing across the polar vortex edge; polar vortex stability and how it is influenced by dynamic processes in the troposphere has led to unprecedented, synoptic-scale stratospheric regions with temperatures below the frost point; in these regions stratospheric ice clouds have been observed, extending over >106km2 during more than 3 weeks. (2) Particle microphysics: heterogeneous nucleation of nitric acid trihydrate (NAT) particles in the absence of ice has been unambiguously demonstrated; conversely, the synoptic scale ice clouds also appear to nucleate heterogeneously; a variety of possible heterogeneous nuclei has been characterised by chemical analysis of the non-volatile fraction of the background aerosol; substantial formation of solid particles and denitrification via their sedimentation has been observed and model parameterizations have been improved. (3) Chemistry: strong evidence has been found for significant chlorine activation not only on polar stratospheric clouds (PSCs) but also on cold binary aerosol; laboratory experiments and field data on the ClOOCl photolysis rate and other kinetic parameters have been shown to be consistent with an adequate degree of certainty; no evidence has been found that would support the existence of yet unknown chemical mechanisms making a significant contribution to polar ozone loss. (4) Global modelling: results from process studies have been implemented in a prognostic chemistry climate model (CCM); simulations with improved parameterisations of processes relevant for polar ozone depletion are evaluated against satellite data and other long term records using data assimilation and detrended fluctuation analysis. Finally, measurements and process studies within RECONCILE were also applied to the winter 2010/11, when special meteorological conditions led to the highest chemical ozone loss ever observed in the Arctic. In addition to quantifying the 2010/11 ozone loss and to understand its causes including possible connections to climate change, its impacts were addressed, such as changes in surface ultraviolet (UV) radiation in the densely populated northern mid-latitudes.
The international research project RECONCILE has addressed central questions regarding polar ozone depletion, with the objective to quantify some of the most relevant yet still uncertain physical and chemical processes and thereby improve prognostic modelling capabilities to realistically predict the response of the ozone layer to climate change. This overview paper outlines the scope and the general approach of RECONCILE, and it provides a summary of observations and modelling in 2010 and 2011 that have generated an in many respects unprecedented dataset to study processes in the Arctic winter stratosphere. Principally, it summarises important outcomes of RECONCILE including (i) better constraints and enhanced consistency on the set of parameters governing catalytic ozone destruction cycles, (ii) a better understanding of the role of cold binary aerosols in heterogeneous chlorine activation, (iii) an improved scheme of polar stratospheric cloud (PSC) processes that includes heterogeneous nucleation of nitric acid trihydrate (NAT) and ice on non-volatile background aerosol leading to better model parameterisations with respect to denitrification, and (iv) long transient simulations with a chemistry-climate model (CCM) updated based on the results of RECONCILE that better reproduce past ozone trends in Antarctica and are deemed to produce more reliable predictions of future ozone trends. The process studies and the global simulations conducted in RECONCILE show that in the Arctic, ozone depletion uncertainties in the chemical and microphysical processes are now clearly smaller than the sensitivity to dynamic variability.