Media SuUB Bremen
https://media.suub.uni-bremen.de:443
The DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.2024-03-28T01:30:07ZInversion of short-lived pollutants in the global atmosphere using remote sensing data
https://media.suub.uni-bremen.de/handle/elib/7787
Title: Inversion of short-lived pollutants in the global atmosphere using remote sensing data
Authors: Nüß, Johann Rasmus
Supervisor: Vrekoussis, Mihalis
1. Expert: Vrekoussis, Mihalis
Experts: Krol, Maarten
Abstract: In the atmosphere, carbon monoxide is a trace gas with a relatively short lifetime in the order of a few months. On a global scale, it affects the climate, because most carbon monoxide is eventually oxidized to the greenhouse gas carbon dioxide. That reaction is also the largest sink of hydroxyl radicals and, therefore, prolongs greenhouse gas lifetimes. Close to the sources of carbon monoxide, concentrations can be high and adversely impact local air quality, because it is a precursor for tropospheric ozone. For these reasons, knowledge about the global distribution of carbon monoxide and its sources is important. Inverse modeling is a powerful top-down technique to constrain trace gas emissions, or refine existing bottom-up source estimates, based on observational data. However, inverse modeling of atmospheric chemistry is not trivial and requires the use of sophisticated systems, which combine elaborate models with a plethora of input data, including remote sensing observations and boundary conditions for the model, e.g. meteorology or prior emission estimates. In this work, such an inverse modeling system will be improved by testing, updating, and revising most of its components. Most prominently, observations from a new satellite instrument, the TROPOspheric Monitoring Instrument (TROPOMI), are introduced into the system. In recent years, the data quality and resolution of satellite instruments have been steadily improving. These improvements inevitably also lead to an increase in the amount of data to be handled. For inverse modeling systems, large observational datasets can become problematic due to computational constraints. In this work, methods for handling those datasets are developed. To investigate the capabilities and limitations of the new observational dataset, multiple inversion experiments are conducted. These experiments target carbon monoxide emissions from three categories, biomass burning, fossil fuel, and secondary production, for the second half of the year 2018 on a global scale. The results suggest that the emissions, especially in the southern hemisphere, are well constrained by the TROPOMI observations. However, the inversion experiments also reveal biases in the optimized emissions, especially in the northern tropics. These biases are linked to an imbalanced prior budget, i.e. to the boundary conditions of the model before the observations are considered. The budget and the biases are improved in multiple steps, most notably by revising the assumed hydroxyl radical distribution and the meteorology.
Keywords: carbon monoxide; TROPOMI; inverse modelling; 4DVAR; atmospheric chemistry; environmental physics
Issue Date: 2024-03-15
Type: Dissertation
DOI: 10.26092/elib/2869
URN: urn:nbn:de:gbv:46-elib77878
Institution: Universität Bremen
Faculty: Fachbereich 01: Physik/Elektrotechnik (FB 01)2024-03-15T00:00:00ZBewältigung von Veränderungsprozessen Richtung agiles Arbeiten aus Sicht der psychoneurowissenschaftlichen Persönlichkeitsforschung
https://media.suub.uni-bremen.de/handle/elib/7793
Title: Bewältigung von Veränderungsprozessen Richtung agiles Arbeiten aus Sicht der psychoneurowissenschaftlichen Persönlichkeitsforschung
Authors: Dietrich, Malte
Other Titles: Coping of change processes towards agile working from the perspective of psycho-neuroscientific personality research
Supervisor: Stahlke, Iris
1. Expert: Stahlke, Iris
Experts: Dicke, Ursula
Abstract: Ausgangspunkt dieser Literaturarbeit ist, dass mögliche Veränderungen von Verhalten und Persönlichkeit als zu optimistisch gesehen werden und mit neurowissenschaftlichen Erkenntnissen nicht vereinbar sind. Aufbauend auf dem als Referenzmodell fungierenden Vier-Ebenen-Modell der Persönlichkeit und Psyche von Prof. Dr. Dr. Gerhard Roth und Prof. Dr. Manfred Cierpka wird die Bewältigung von Veränderungen untersucht. Es zeigt sich, dass diese erheblich von unbewussten Anteilen der Persönlichkeit bedingt ist. Wahrnehmung, Verarbeitung und Reaktionen, sowohl physiologischer, emotionaler und behavioraler Art, werden davon beeinflusst. Die Ausschüttung von Neurotransmittern und Hormonen hat dabei eine entscheidende Rolle. Unterschiedliche Persönlichkeitstypen handeln situationsspezifisch variabel, jedoch in einem stark von den unbewussten Anteilen bestimmten Rahmen. Die bewussten Anteile der Persönlichkeit haben wichtige Funktionen wie das Reflektieren und zielorientierte Handeln. Die Möglichkeiten und Grenzen der Veränderbarkeit verschiedener Hirnareale ist unterschiedlich, was mit Herausforderungen bei Veränderungen für Personen und Organisationen einhergeht: Bestimmte Bereiche der Persönlichkeit können relativ leicht verändert und neuen Anforderungen angepasst werden, andere nur schwierig. In einem von der Organisation initiierten Veränderungsprozess Richtung agiles Arbeiten kann eine hohe subjektive Person-Umwelt-Passung nur erreicht werden, wenn die unbewussten Anteile der Persönlichkeit den Anforderungen zu großen Teilen entsprechen.
Keywords: Agil; Bewältigung; Bewusst; Coping; Gewohnheit; Hormone; Neurotransmitter; Neurowissenschaft; Persönlichkeit; Persönlichkeitstypen; Unbewusst; Veränderung; Veränderbarkeit
Issue Date: 2024-03-14
Type: Dissertation
DOI: 10.26092/elib/2875
URN: urn:nbn:de:gbv:46-elib77937
Institution: Universität Bremen
Faculty: Fachbereich 11: Human- und Gesundheitswissenschaften (FB 11)2024-03-14T00:00:00ZThe impacts of profile concavity on turbidite deposits: Insights from the submarine canyons on global continental margins
https://media.suub.uni-bremen.de/handle/elib/7806
Title: The impacts of profile concavity on turbidite deposits: Insights from the submarine canyons on global continental margins
Authors: Yu, Kaiqi; Miramontes, Elda; Cartigny, Matthieu J.B.; Yang, Yuping; Xu, Jingping
Abstract: Submarine canyons are primary conduits for turbidity currents transporting terrestrial sediments, nutrients, pollutants and organic carbon to the deep sea. The concavity in the longitudinal profile of these canyons (i.e. the downstream flattening rate along the profiles) influences the transport processes and results in variations in turbidite thickness, impacting the transfer and burial of particles. To better understand the controlling mechanisms of canyon concavity on the distribution of turbidite deposits, here we investigate the variation in sediment accumulation as a function of canyon concavity of 20 different modern submarine canyons, distributed on global continental margins. In order to effectively assess the isolated impact of the concavity of 20 different canyons, a series of two-dimensional, depth-resolved numerical simulations are conducted. Simulation results show that the highly concave profile (e.g. Surveyor and Horizon) tends to concentrate the turbidite deposits mainly at the slope break, while nearly straight profiles (e.g. Amazon and Congo) result in deposition focused at the canyon head. Moderately concave profiles with a smoother canyon floor (e.g. Norfolk-Washington and Mukluk) effectively facilitate the downstream transport of suspended sediments in turbidity currents. Furthermore, smooth and steep upper reaches of canyons commonly contribute to sediment bypass (i.e. Mukluk and Chirikof), while low slope angles lead to deposition at upper reaches (i.e. Bounty and Valencia). At lower reaches, the distribution of turbidite deposits is consistent with the occurrence of hydraulic jumps. Under the influence of different canyon concavities, three types of deposition patterns are inferred in this study, and verified by comparison with observed turbidite deposits on the modern or paleo-canyon floor. This study demonstrates a potential difference in sediment transport efficiency of submarine canyons with different concavities, which has potential consequences for sediment and organic carbon transport through submarine canyons.
Keywords: Turbidity currents; Submarine canyon; Hydrodynamics; Turbidite deposition; Seafloor morphology
Issue Date: 2024-03-13
Journal/Edited collection: Geomorphology
Start page: 109157
Type: Artikel/Aufsatz
ISSN: 0169555X
DOI: 10.26092/elib/2888
URN: urn:nbn:de:gbv:46-elib78061
Institution: Universität Bremen
Faculty: Fachbereich 05: Geowissenschaften (FB 05); Marum – Zentrum für Marine Umweltwissenschaften2024-03-13T00:00:00ZKinetic stabilization of low valent main group compounds
https://media.suub.uni-bremen.de/handle/elib/7777
Title: Kinetic stabilization of low valent main group compounds
Authors: Duvinage, Daniel
Other Titles: Kinetische Stabilisierung von niedervalenten Hauptgruppen-Verbindungen
Supervisor: Beckmann, Jens
1. Expert: Beckmann, Jens
Experts: Staubitz, Anne; Schulz, Axel
Abstract: Highly reactive species, such as cations and radicals, are often proposed as intermediates in reaction mechanisms. The stabilization and isolation of such species is an ongoing challenge in chemistry. In this work a plethora of bis-substituted meta-terphenyl element compounds of group 13, 15 and 16 were synthesized and the first kinetically stabilized indinium ion (2,6-Mes2C6H3)2In+ as a 4 valence electron species, the first kinetically stabilized stibenium and bismuthenium ion (2,6-Mes2C6H3)2E+ (E = Sb, Bi) as 6 valence electron species and the first kinetically stabilized tellurenyl radical cation (2,6-Mes2C6H3)2Te*+ as a 7 valence electron species were successfully synthesized and fully characterized, opening a new area of compound classes.
Keywords: meta-terphenyl; kinetic stabilization; low valency; main group; group 13; group 15; group 16; indium; antimony; bismuth; tellurium
Issue Date: 2024-03-08
Type: Dissertation
DOI: 10.26092/elib/2859
URN: urn:nbn:de:gbv:46-elib77773
Institution: Universität Bremen
Faculty: Fachbereich 02: Biologie/Chemie (FB 02)2024-03-08T00:00:00Z