Lagrangian transport evaluation of atmospheric chemistry in the Mediterranean region

Global observations of the chemical composition of the atmosphere are essential for understanding and studying the present and future state of the earth's atmosphere. However, by analyzing field experiments the consideration of the atmospheric motion is indispensable, because transport enables different chemical species, with different local natural and anthropogenic sources, to interact chemically and so consequently influences the chemical composition of the atmosphere. The distance over which that transport occurs is highly dependent upon meteorological conditions (e.g., wind speed, precipitation) and the properties of chemical species itself (e.g., solubility, reactivity). This interaction between chemistry and dynamics makes the study of atmospheric chemistry both difficult and challenging, and also demonstrates the relevance of including the atmospheric motions in that context. In this doctoral thesis the large-scale transport of air over the eastern Mediterranean region during summer 2001, with a focus on August during the Mediterranean Intensive Oxidant Study (MINOS) measurement campaign, was investigated from a lagrangian perspective. Analysis of back trajectories demonstrated transport of polluted air masses from western and eastern Europe in the boundary layer, from the North Atlantic/North American area in the middle end upper troposphere and additionally from South Asia in the upper troposphere towards the eastern Mediterranean. Investigation of air mass transport near the tropopause indicated enhanced cross-tropopause transport relative to the surrounding area over the eastern Mediterranean region in summer. A large band of air mass transport across the dynamical tropopause develops in June, and is shifted toward higher latitudes in July and August. This shifting is associated with the development and the intensification of the Arabian and South Asian upper-level anticyclones and consequential with areas of maximum clear-air turbulence, hypothesizing quasi-permanent areas with turbulent mixing of tropospheric and stratospheric air during summer over the eastern Mediterranean as a result of large-scale synoptic circulation. In context with the latex knowledge about the transport of polluted air masses towards the Mediterranean and with increasing emissions, especially in developing countries like India, this likely gains in importance.

Dynamik diabatischer Rossby-Wellen

Diabatische Rossby-Wellen (DRWs) sind zyklonale Wirbel in der unteren Troposphäre, welche sich durch einen thermodynamisch-dynamischen Mechanismus kontinuierlich regenerieren und dabei schnell propagieren können. Vorangehende Untersuchungen schreiben derartigen zyklonalen Wirbeln das Potential zu, unter Wechselwirkung mit einer Anomalie an der Tropopause eine rapide Zyklonenintensivierung und folglich extreme Wetterereignisse hervorrufen zu können. DRWs wurden bisher meist in idealisierten Studien untersucht, woraus sich noch einige offene Fragen zu diesem Phänomen, besonders in realen Modelldaten, ergeben.rnrnIm Mittelpunkt dieser Arbeit steht die Fallstudie einer DRW, die im Dezember 2005 über dem Nordatlantik auftrat. Der Lebenszyklus des Systems ist über mehrere Tage und durch verschiedene Phasen verfolgbar und resultiert in einer explosiven Druckvertiefung. Zur Untersuchung der Fallstudie wurde mit operationellen Daten eines Globalmodelles sowie mit den Resultaten eines feinskaligeren Regionalmodelles gearbeitet, auf welche unterschiedliche Analysewerkzeuge angewendet wurden. rnrnDie eingehende Untersuchung der Propagationsphase der DRW bekräftigte das Vorhandensein von genügend Feuchte und Baroklinität als essentiell für den Propagationsmechanismus und die Intensität der DRW. Während der Propagationsphase arbeitet der selbsterhaltende DRW-Mechanismus unabhängig von einer von den Wellen an der Tropopause ausgehenden Anregung. Sensitivitätsstudien mit dem Regionalmodell, in denen die Umgebungsbedingungen der DRW lokal modifiziert wurden, ergaben, dass die Propagation einen relativ robusten Ablauf darstellt. Dementsprechend war in den vier untersuchten operationellen Vorhersagen die Propagationsphase gut wiedergegeben, während die rapide Intensivierung, wie sie gemäß den Analysen aufgetreten ist, von zwei der Vorhersagen verfehlt wurde.rnrnBei der Untersuchung der Intensivierungsphase stellten sich die Position und die zeitliche Abstimmung der Bewegung der Anomalie an der Tropopause relativ zur DRW in der unteren Troposphäre sowie die Stärke der Systeme als entscheidende Einflussfaktoren heraus. In den Entwicklungen der Sensitivitätssimulationen deutete sich an, dass ein unabhängig von der DRW an geeigneter Position entstandener zyklonaler Wirbel konstruktiver zu einer starken Zyklonenintensivierung beitragen kann als die DRW.rnrnIm zweiten Teil der Arbeit wurde ein Datensatz über die Nordhemisphäre für die Jahre 2004-2008 hinsichtlich des geographischen Vorkommens und der Intensivierung von DRWs untersucht. DRWs ereigneten sich in diesem Zeitraum über dem Atlantik (255 DRWs) halb so oft wie über dem Pazifik (515 DRWs). Ihre Entstehungsgebiete befanden sich über den Ostteilen der Kontinente und den Westhälften der Ozeane. Die Zugbahnen folgten größtenteils der baroklinen Zone der mittleren Breiten. Von den erfassten DRWs intensivierten sich im Atlanik 16% zu explosiven Tiefdruckgebieten, über dem Pazifik liegt der Anteil mit 11% etwas niedriger. Damit tragen DRWs zu etwa 20% der sich explosiv intensivierenden außertropischen Zyklonen bei.

The prehistoric inhabitants of the Wadi Howar : an anthropological study of human skeletal remains from the Sudanese part of the Eastern Sahara

All currently available human skeletal remains from the Wadi Howar (Eastern Sahara, Sudan) were employed in an anthropological study. The study’s first aim was to describe this unique 5th to 2nd millennium BCE material, which comprised representatives of all three prehistoric occupation phases of the region. Detecting diachronic differences in robusticity, occupational stress levels and health within the spatially, temporally and culturally heterogeneous sample was its second objective. The study’s third goal was to reveal metric and non-metric affinities between the different parts of the series and between the Wadi Howar material and other relevant prehistoric as well as modern African populations. rnThe reconstruction and comprehensive osteological analysis of 23 as yet unpublished individuals, the bulk of the Wadi Howar series, constituted the first stage of the study. The analyses focused on each individual’s in situ position, state of preservation, sex, age at death, living height, living weight, physique, biological ancestry, epigenetic traits, robusticity, occupational stress markers, health and metric as well as morphological characteristics. Building on the results of these efforts and the re-examination of the rest of the material, the Wadi Howar series as a whole, altogether 32 individuals, could be described. rnA wide variety of robusticity, occupational stress and health variables was evaluated. The pre-Leiterband (hunter-gatherer-fisher/hunter-gatherer-fisher-herder) and the Leiterband (herder-gatherer) data of over a third of these variables differed statistically significantly or in tendency from each other. The Leiterband sub-sample was characterised by higher enamel hypoplasia frequencies, lower mean ages at death and less pronounced expressions of occupational stress traits. This pattern was interpreted as evidence that the adoption and intensification of animal husbandry did probably not constitute reactions to worsening conditions. Apart from that, the relevant observations, noteworthy tendencies and significant differences were explained as results of a broader spectrum of pre-Leiterband subsistence activities and the negative side effects of the increasingly specialised herder-gatherer economy of the Leiterband phase. rnUsing only the data which could actually be collected from it, multiple, separate, individualised discriminant function analyses were carried out for each Wadi Howar skeleton to determine which prehistoric and which modern comparative sample it was most similar to. The results of all individual analyses were then summarised and examined as a whole. Thus it became possible to draw conclusions about the affinities the Wadi Howar material shared with prehistoric as well as modern populations and to answer questions concerning the diachronic links between the Wadi Howar’s prehistoric populations. When the Wadi Howar remains were positioned in the context of the selected prehistoric (Jebel Sahaba/Tushka, A-Group, Malian Sahara) and modern comparative samples (Southern Sudan, Chad, Mandinka, Somalis, Haya) in this fashion three main findings emerged. Firstly, the series as a whole displayed very strong affinities with the prehistoric sample from the Malian Sahara (Hassi el Abiod, Kobadi, Erg Ine Sakane, etc.) and the modern material from Southern Sudan and, to a lesser extent, Chad. Secondly, the pre-Leiterband and the Leiterband sub-sample were closer to the prehistoric Malian as well as the modern Southern Sudanese material than they were to each other. Thirdly, the group of pre-Leiterband individuals approached the Late Pleistocene sample from Jebel Sahaba/Tushka under certain circumstances. A theory offering explanations for these findings was developed. According to this theory, the entire prehistoric population of the Wadi Howar belonged to a Saharo-Nilotic population complex. The Jebel Sahaba/Tushka population constituted an old Nilotic and the early population of the Malian Sahara a younger Saharan part of this complex. The pre-Leiterband groups probably colonised the Wadi Howar from the east, either during or soon after the original Saharo-Nilotic expansion. Unlike the pre-Leiterband groups, the Leiterband people originated somewhere west of the Wadi Howar. They entered the region in the context of a later, secondary Saharo-Nilotic expansion. In the process, the incoming Leiterband groups absorbed many members of the Wadi Howar’s older pre-Leiterband population. The increasing aridification of the Wadi Howar region ultimately forced its prehistoric inhabitants to abandon the wadi. Most of them migrated south and west. They, or groups closely related to them, probably were the ancestors of the majority of the Nilo-Saharan-speaking pastoralists of modern-day Southern Sudan and Eastern Chad.

Etablierung und Optimierung von Therapeutischem Drug Monitoring für die Psychopharmakotherapie von Patienten mit Substanzabhängigkeit

Therapeutisches Drug Monitoring (TDM) findet Anwendung in der Therapie mit Immunosuppressiva, Antibiotika, antiretroviraler Medikation, Antikonvulsiva, Antidepressiva und auch Antipsychotika, um die Effizienz zu steigern und das Risiko von Intoxikationen zu reduzieren. Jedoch ist die Anwendung von TDM für Substanzen, die Einsatz finden in der Rückfallprophylaxe, der Substitution oder dem Entzug von Abhängigkeitserkrankungen nicht etabliert. Für diese Arbeit wurde im ersten Schritt eine sensitive Rating-Skala mit 22 Items entwickelt, mit Hilfe derer der theoretische Nutzen von TDM in der Pharmakotherapie von substanzbezogenen Abhängigkeitserkrankungen auf der Basis von pharmakologischen Eigenschaften der Medikamente und von Patientencharakteristika evaluiert wurde. Die vorgenommene Einschätzung zeigte für Bupropion, Buprenorphin, Disulfiram (oder einen Metaboliten), Methadon (chirale Bestimmung wenn möglich) und Naltrexon einen potentiellen Nutzen von TDM.rnFür die meisten Medikamente, die zur Behandlung von Abhängigkeitserkrankungen zugelassen sind, fehlen valide Messverfahren für TDM. Im Alltag werden überwiegend Drogen Screening-Tests in Form immunologischer Schnelltests angewendet. Für die Anwendung von TDM wurden in dieser Arbeit chromatographische Verfahren für die Bestimmung von Naltrexon und 6β-Naltrexol, Bupropion und Hydroxybupropion sowie R,S-Methadon und R,S-2-Ethyliden-1,5-dimethyl-3,3-diphenylpyrrolidin entwickelt, optimiert und validiert. Es handelt sich dabei HPLC-UV-Methoden mit Säulenschaltung sowie zur Bestimmung von Naltrexon und 6β-Naltrexol zusätzlich eine LC-MS/MS-Methode. Voraussetzung für die Interpretation der Plasmaspiegel ist im Wesentlichen die Kenntnis eines therapeutischen Bereichs. Für Naltrexon und seinen aktiven Metaboliten 6β-Naltrexol konnte eine signifikante Korrelation zwischen dem auftretenden Craving und der Summenkonzentration gefunden werden. Mittels Receiver-Operation-Characteristics-Kurven-Analyse wurde ein Schwellenwert von 16,6 ng/ml ermittelt, oberhalb dessen mit einem erhöhten Ansprechen gerechnet werden kann. Für Levomethadon wurde bezüglich der Detoxifikationsbehandlung ein Zusammenhang in der prozentualen Reduktion des Plasmaspiegels und den objektiven und subjektiven Entzugssymptomen gefunden. rnDoch nicht nur die Wirkstoffe, sondern auch das Patientenmerkmal substanzbezogene Abhängigkeit wurde charakterisiert, zum einen bezüglich pharmakokinetischer Besonderheiten, zum anderen in Hinsicht auf die Therapietreue (Adhärenz). Für Patienten mit komorbider Substanzabhängigkeit konnte eine verminderte Adhärenz unabhängig von der Hauptdiagnose gezeigt werden. Die Betrachtung des Einflusses von veränderten Leberwerten zeigt für komorbide Patienten eine hohe Korrelation mit dem Metabolisiererstatus, nicht aber für Patienten ohne Substanzabhängigkeit.rnÜbergeordnetes Ziel von TDM ist die Erhöhung der Therapiesicherheit und die Steigerung der Therapieeffizienz. Dies ist jedoch nur möglich, wenn TDM im klinischen Alltag integriert ist und korrekt eingesetzt wird. Obwohl es klare Evidenz für TDM von psychiatrischer Medikation gibt, ist die Diskrepanz zwischen Laborempfehlung und der klinischen Umsetzung hoch. Durch Intensivierung der interdisziplinären Zusammenarbeit zwischen Ärzten und Labor, der Entwicklung von interaktivem TDM (iTDM), konnte die Qualität der Anwendung von TDM verbessert und das Risiko von unerwünschten Arzneimittelwirkungen vermindert werden. rnInsgesamt konnte durch die eigenen Untersuchungen gezeigt werden, dass TDM für die medikamentöse Einstellung von Patienten mit Abhängigkeitserkrankung sinnvoll ist und dass optimales TDM eine interdisziplinäre Zusammenarbeit erfordert.rn

Mineral dust mobilisation, transport, and deposition in different climate epochs

Mineral dust is an important component of the Earth's climate system and provides essential nutrientsrnto oceans and rain forests. During atmospheric transport, dust particles directly and indirectly influencernweather and climate. The strength of dust sources and characteristics of the transport, in turn, mightrnbe subject to climatic changes. Earth system models help for a better understanding of these complexrnmechanisms.rnrnThis thesis applies the global climate model ECHAM5/MESSy Atmospheric Chemistry (EMAC) for simulationsrnof the mineral dust cycle under different climatic conditions. The prerequisite for suitable modelrnresults is the determination of the model setup reproducing the most realistic dust cycle in the recentrnclimate. Simulations with this setup are used to gain new insights into properties of the transatlanticrndust transport from Africa to the Americas and adaptations of the model's climate forcing factors allowrnfor investigations of the impact of climatic changes on the dust cycle.rnrnIn the first part, the most appropriate model setup is determined through a number of sensitivity experiments.rnIt uses the dust emission parametrisation from Tegen et al. 2002 and a spectral resolutionrnof T85, corresponding to a horizontal grid spacing of about 155 km. Coarser resolutions are not able tornaccurately reproduce emissions from important source regions such as the Bodele Depression in Chad orrnthe Taklamakan Desert in Central Asia. Furthermore, the representation of ageing and wet deposition ofrndust particles in the model requires a basic sulphur chemical mechanism. This setup is recommended forrnfuture simulations with EMAC focusing on mineral dust.rnrnOne major branch of the global dust cycle is the long-range transport from the world's largest dustrnsource, the Sahara, across the Atlantic Ocean. Seasonal variations of the main transport pathways to thernAmazon Basin in boreal winter and to the Caribbean during summer are well known and understood,rnand corroborated in this thesis. Both Eulerian and Lagrangian methods give estimates on the typicalrntransport times from the source regions to the deposition on the order of nine to ten days. Previously, arnhuge proportion of the dust transported across the Atlantic Ocean has been attributed to emissions fromrnthe Bodele Depression. However, the contribution of this hot spot to the total transport is very low inrnthe present results, although the overall emissions from this region are comparable. Both model resultsrnand data sets analysed earlier, such as satellite products, involve uncertainties and this controversy aboutrndust transport from the Bodele Depression calls for future investigations and clarification.rnrnAforementioned characteristics of the transatlantic dust transport just slightly change in simulationsrnrepresenting climatic conditions of the Little Ice Age in the middle of the last millennium with meanrnnear-surface cooling of 0.5 to 1 K. However, intensification of the West African summer monsoon duringrnthe Little Ice Age is associated with higher dust emissions from North African source regions and wetterrnconditions in the Sahel. Furthermore, the Indian Monsoon and dust emissions from the Arabian Peninsula,rnwhich are affected by this circulation, are intensified during the Little Ice Age, whereas the annual globalrndust budget is similar in both climate epochs. Simulated dust emission fluxes are particularly influencedrnby the surface parameters. Modifications of the model do not affect those in this thesis, to be able tornascribe all differences in the results to changed forcing factors, such as greenhouse gas concentrations.rnDue to meagre comparison data sets, the verification of results presented here is problematic. Deeperrnknowledge about the dust cycle during the Little Ice Age can be obtained by future simulations, based onrnthis work, and additionally using improved reconstructions of surface parameters. Better evaluation ofrnsuch simulations would be possible by refining the temporal resolution of reconstructed dust depositionrnfluxes from existing ice and marine sediment cores.

Potential vorticity and moisture in extratropical cyclones : climatology and sensitivity experiments

The development of extratropical cyclones can be seen as an interplay of three positive potential vorticity (PV) anomalies: an upper-level stratospheric intrusion, low-tropospheric diabatically produced PV, and a warm anomaly at the surface acting as a surrogate PV anomaly. In the mature stage they become vertically aligned and form a “PV tower” associated with strong cyclonic circulation. This paradigm of extratropical cyclone development provides the basis of this thesis, which will use a climatological dataset and numerical model experiments to investigate the amplitude of the three anomalies and the processes leading in particular to the formation of the diabatically produced low-tropospheric PV anomaly.rnrnThe first part of this study, based on the interim ECMWF Re-Analysis (ERA-Interim) dataset, quantifies the amplitude of the three PV anomalies in mature extratropical cyclones in different regions in the Northern Hemisphere on a climatological basis. A tracking algorithm is applied to sea level pressure (SLP) fields to identify cyclone tracks. Surface potential temperature anomalies ∆θ and vertical profiles of PV anomalies ∆PV are calculated at the time of the cyclones’ minimum SLP and during the intensification phase 24 hours before in a vertical cylinder with a radius of 200 km around the surface cyclone center. To compare the characteristics of the cyclones, they are grouped according to their location (8 regions) and intensity, where the central SLP is used as a measure of intensity. Composites of ∆PV profiles and ∆θ are calculated for each region and intensity class at the time of minimum SLP and during the cyclone intensification phase.rnrnDuring the cyclones’ development stage the amplitudes of all three anomalies increase on average. In the mature stage all three anomalies are typically larger for intense than for weak winter cyclones [e.g., 0.6 versus 0.2 potential vorticity units (PVU) at lower levels, and 1.5 versus 0.5 PVU at upper levels].rnThe regional variability of the cyclones’ vertical structure and the profile evolution is prominent (cyclones in some regions are more sensitive to the amplitude of a particular anomaly than in other regions). Values of ∆θ and low-level ∆PV are on average larger in the western parts of the oceans than in the eastern parts. In addition, a large seasonal variability can be identified, with fewer and weaker cyclones especially in the summer, associated with higher low-tropospheric PV values, but also with a higher tropopause and much weaker surface potential temperature anomalies (compared to winter cyclones).rnrnIn the second part, we were interested in the diabatic low-level part of PV towers. Evaporative sources were identified of moisture that was involved in PV production through condensation. Lagrangian backward trajectories were calculated from the region with high PV values at low-levels in the cyclones. PV production regions were identified along these trajectories and from these regions a new set of backward trajectories was calculated and moisture uptakes were traced along them. The main contribution from surface evaporation to the specific humidity of the trajectories is collected 12-72 hours prior to therntime of PV production. The uptake region for weaker cyclones with less PV in the centre is typically more localized with reduced uptake values compared to intense cyclones. However, in a qualitative sense uptakes and other variables along single trajectories do not vary much between cyclones of different intensity in different regions.rnrnA sensitivity study with the COSMO model comprises the last part of this work. The study aims at investigating the influence of synthetic moisture modification in the cyclone environment in different stages of its development. Moisture was eliminated in three regions, which were identified as important moisture source regions for PV production. Moisture suppression affected the cyclone the most in its early phase. It led to cyclolysis shortly after its genesis. Nevertheles, a new cyclone formed on the other side of a dry box and developed relatively quickly. Also in other experiments, moisture elimination led to strong intensity reduction of the surface cyclone, limited upper-level development, and delayed or missing interaction between the two.rnrnIn summary, this thesis provides novel insight into the structure of different intensity categories of extratropical cyclones from a PV perspective, which corroborates the findings from a series of previous case studies. It reveals that all three PV anomalies are typically enhanced for more intense cyclones, with important regional differences concerning the relative amplitude of the three anomalies. The moisture source analysis is the first of this kind to study the evaporation-condensation cycle related to the intensification of extratropical cyclones. Interestingly, most of the evaporation occurs during the 3 days prior to the time of maximum cyclone intensity and typically extends over fairly large areas along the track of the cyclone. The numerical model case study complements this analysis by analyzing the impact of regionally confined moisture sources for the evolution of the cyclone.