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Institute
The goal of limited area models (LAMs) is to downscale coarse-gridded general circulation model output to represent small-scale features of weather and climate. The LAM needs information from the driving coarse-gridded model passing through its lateral boundaries. The treatment of this information transfer causes inconsistencies between driving and nested models and, subsequently, issues in regional weather and climate simulations. This work examines errors arising from choices taken by the modeler (temporal update frequency of boundary data, spatial resolution jump, and numerical lateral boundary formulation) systematically in an idealized simulation environment. So-called Big-Brother Experiments were performed with the LAM COSMO-CLM (0.11° grid spacing). A baroclinic wave in a zonal channel was simulated over flat terrain with and without a Gaussian hill. The results reveal that the quality of the driving data, here represented by simulations only differing from the LAM simulations by reduced spatial resolution, dominates the performance of the nested model. Consequently, at the simulated mesoscale, the performance of the nested small-scale model simulations is weakly sensitive to the numerical lateral boundary formulation (Davies relaxation or the newly implemented, computationally less demanding Mesinger Eta-model formulation). The performance sensitivity to boundary update frequency and resolution jump is small when at least 6-hourly updates and a resolution jump factor of maximally six is used. Gaussian hill LAM simulations illustrated the strength of downscaling; they can represent small-scale features missing in the coarse-scale driving simulations. In the idealized simulation experiments, spectral nudging is not advisable as it imprints the driving models deficits on the nested simulation.
The impact of precipitation in shallow cumulus convection on the moisture variance and third-order moments of moisture is investigated with the help of large-eddy simulations. Three idealized simulations based on the Rain in Cumulus over the Ocean field experiment are analyzed: one nonprecipitating, on a smaller domain, and two precipitating cases, on a larger domain with different initial profiles of moisture. Results show that precipitation and the associated cloud organization lead to increased generation of higher-order moments (HOM) of moisture compared to the nonprecipitating case. To understand the physical mechanism and the role of individual processes in this increase, budgets of HOM of moisture are studied. Microphysics directly decreases the generation of HOM of moisture, but this effect is not dominant. The gradient production term is identified as the main source term in the HOM budgets. The influence of the gradient production term on moisture variance is further examined separately in cloud active and nonactive regions. The main contribution to the gradient production term comes from the smaller cloud active region because of the stronger moisture flux. Further analyses of the horizontal and vertical cross sections of moisture fluctuations show that the precipitation-induced downdrafts and updrafts are the main mechanism for the generation of moisture variance. The variance increase is linked to shallow dry downdraft regions with horizontal divergence in the subcloud layer, moist updrafts with horizontal convergence in the bulk cloud layer, and finally wider areas of horizontal divergence in the cloud inversion layer.
The organisation of parking is a key challenge to more sustainable mobility in urban areas, as its pricing and availability affect the rates of private car ownership and use. However, changing parking policies is a challenging issue for local politicians and planners because residents frequently oppose changes or restrictions to conditions they have taken for granted such as on-street parking in a public space. The aim of this paper is firstly to assess how the parking policy of an urban neighbourhood can be structured to contribute to more sustainable mobility and to increase liveability in the neighbourhood. The second aim is to apply the policies reviewed to an example neighbourhood. For this purpose, we systematically reviewed academic literature and identified five types of relevant parking policies: (i) maximum parking requirements, (ii) physical detachment of residence and parking space, (iii) residential parking permits and the limitation of available parking space, (iv) performance-based pricing and (v) parking as a demand management strategy. We discovered that most research focuses on econometric models about parking and that studies rarely address the effects of parking on the quality of life in neighbourhoods. Therefore, we need further research regarding the relationship of parking and liveability. We conclude that for the implementation of such parking policies in an example neighbourhood, the municipality needs to develop a mobility vision for its city. It has to understand parking as a tool for transportation demand management to increase the acceptance of parking policy concepts and to avoid spillover problems. Finally, in the German case, as in most other countries, states and municipalities need to redesign their legal frameworks to be able to manage parking supply better and to react to changes related to digital developments and parking. The findings have implications for other European neighbourhoods regarding the transfer from research to local circumstances and applications for the whole city.
Motions on planetary spatial scales in the atmosphere are governed by the planetary geostrophic equations. However, little attention has been paid to the interaction between the baroclinic and barotropic flows within the planetary geostrophic scaling. This is the focus of the present study, which utilizes planetary geostrophic equations for a Boussinesq fluid supplemented by a novel evolution equation for the barotropic flow. The latter is affected by meridional momentum flux due to baroclinic flow and drag by the surface wind. The barotropic wind, on the other hand, affects the baroclinic flow through buoyancy advection. Via a relaxation towards a prescribed buoyancy profile the model produces realistic major features of the zonally symmetric wind and temperature fields. We show that there is considerable cancellation between the barotropic and the baroclinic surface zonal mean zonal winds. Linear and nonlinear model responses to steady diabatic zonally asymmetric forcing are investigated, and the arising stationary waves are interpreted in terms of analytical solutions. We also study the problem of baroclinic instability on the sphere within the present model.
As a cognitively-mediated response, autonomous adaptation at farm-gate levels constitutes reactionary actions by farmers against climate impacts. These actions are shaped by interacting factors such as household characteristics, livelihood scope and resources. It is driven by the goal of adapting cultivated farmlands to climate and for sustaining crop yields. Thus, interest in balancing adaptation goals with protection of vegetation conditions is less of a priority. Lack of research interest in understanding the gap between objectives of reactionary adaptation and protection of surface conditions (vegetation canopies) is a gap in research. In many studies, farm-gate level adaptation is described as a set of zero-feedback actions in response to climate impacts. This perception conceals the stress and impact-engendering attribute of reactionary adaptation. Inspired towards addressing this conceptual gap; this study investigates impact of farmers’ reactionary adaptation on vegetation cover in Keffi, Nasarawa, Nigeria. A twenty-year time-series NDVI and rainfall datasets are linearly regressed to examine the extent of NDVI-rainfall sensitivity. A weak linear relationship between NDVI and rainfall in Keffi for the period, 1999-2018 is observed. At a regression slope of 0.001, R squared, R2=0.129 (implying that only about 13% of the variability in NDVI in Keffi are explained by rainfall amount) and a bivariate regression coefficient, r=0.359; statistical evidence shows that rainfall amount are not significant predictors of NDVI in Keffi. In investigating the possible interference of non-rainfall factors on vegetation productivity (NDVI) in Keffi; a residual trend (RESTREND) analysis was carried out. Regression of residuals from NDVI-Rainfall linear regression produced a R=0.192 with a negative and downwards slope. The downward character of the RESTREND slope is suggestive of non-rainfall factors contained in the residuals. In validating the RESTREND analysis, a comparative analysis between observed and predicted NDVI derived from a reference NDVI value of 0.46 was carried out. The NDVI value of 0.46, is empirically assumed to be average NDVI value expected at a minimum rainfall amount of 850mm/year reported in tropical Savanna ecosystems. Using this empirical relationship, NDVI values were predicted for Keffi. Even at higher rainfall amounts≈1340mm/year, amounts were unable to produce corresponding higher NDVI values; rather a more plausible correlation between reference-derived predicted NDVI values and rainfall was obtained. A further analysis with predicted NDVI values, based on 1999 NDVI value in Keffi returned higher NDVI units than observed NDVI values. This strengthens the attribution of the possible interference of rainfall-NDVI sensitivity by non-rainfall factors like human activities on vegetation productivity. Surface soil analysis to exclude potential impacts of soil nutrients and moisture deficiency on vegetation productivity, showed that soil had insignificant effect on vegetation dynamics. Further inferential analysis, using the inter-annual NDVI and the reclassified bi-decadal NDVI maps showed that spatial vegetation distribution in Keffi were driven by farmers inter-annual rotational cultivation footprints than rainfall variability. With a three-class categorization, “gain, loss and significant loss”, the spatial distribution of vegetation in Keffi between (1999-2008) and (2009-2018) was assessed. Temporal condition (stressed and healthy) across the three classes supports the attribution of farmers’ reactionary adaptation and cultivation practices on the dynamic spatial vegetation distribution. Between 1999 -2018, an increase in areas with significant vegetation loss (42%), so with a decrease of -25% in areas with healthy vegetation was observed. The character of vegetation cover across the two decadal time slices, reflects landuse intensity and unsustainable farming practices. Preferences for modification of cultivation practices and changes in seed by farmers exerts positive feedbacks on vegetation cover. Higher statistical measures, 38.4% (yearly cropping) and 44% (shifting cultivation with less fallow periods) were observed in the chi-square analysis. These measures were higher than 2.0% relating to shifting cultivation with more fallow periods. While 11.6% farmers noted cultural practices as reasons for preferred cultivation methods, 48.4% farmers attributed climate as reason behind cultivation modification. This was higher than 24.4% who linked issues of tenure rights to cultivation practices. With preferences for yield- breaching strategies, the non-receding cultivation and shorter fallow practices in Keffi triggers feedback on vegetation dynamics. Evidence from this study shows that the NDVI-rainfall functional sensitivity in Keffi is plausibly dampened by effects of reactionary farm-gate level adaptation practices.
We present novel measurements of five short-lived brominated source gases (CH2Br2, CHBr3, CH2ClBr, CHCl2Br and CHClBr2) obtained using a gas chromatograph-mass spectrometer system on board the High Altitude and Long Range Research Aircraft (HALO). The instrument is extremely sensitive due to the use of chemical ionisation, allowing detection limits in the lower parts per quadrillion (10-15) range. Data from three campaigns using the HALO aircraft are presented, where the Upper Troposphere/Lower Stratosphere (UTLS) of the Northern Hemisphere mid to high latitudes were sampled during winter and during late summer to early fall. We show that an observed decrease with altitude in the stratosphere is consistent with the relative lifetimes of the different compounds. Distributions of the five source gases and total organic bromine just below the tropopause shows an increase in mixing ratio with latitude, in particular during polar winter. This increase in mixing ratio is explained by increasing lifetimes at higher latitudes during winter. As the mixing ratio at the extratropical tropopause are generally higher than those derived for the tropical tropopause, extratropical troposphere-to-stratosphere transport will result in elevated levels of organic bromine in comparison to air transported over the tropical tropopause. The observations are compared to model estimates using different emission scenarios. A scenario which has emissions most strongly concentrated to low latitudes cannot reproduce the observed latitudinal distributions and will tend to overestimate bromine input through the tropical tropopause from CH2Br2 and CHBr3. Consequently, the scenario also overestimates the amount of brominated organic gases in the stratosphere. The two scenarios with the highest overall emissions of CH2Br2 tend to overestimate mixing ratios at the tropical tropopause but are in much better agreement with extratropical tropopause values, showing that not only total emissions but also latitudinal distributions in the emissions are of importance. While an increase in tropopause values with latitude is reproduced with all emission scenarios during winter, the simulated extratropical tropopause values are on average lower than the observations during late summer to fall. We show that a good knowledge of the latitudinal distribution of tropopause mixing ratios and of the fractional contributions of tropical and extratropical air is needed to derive stratospheric inorganic bromine in the lowermost stratosphere from observations. Depending on the underlying emission scenario, differences of a factor 2 in reactive bromine derived from observations and model outputs are found for the lowermost stratosphere, based on source gas injection. We conclude that a good representation of the contributions of different source regions is required in models for a robust assessment of the role of short-lived halogen source gases on ozone depletion in the UTLS.
During the last decades mammalian intracranial structures like the ethmoidal region have rarely been a focus of morphological studies, as they required invasive techniques. Contrary, the ontogeny of the fetal nasal capsule could easily be investigated based on histological material. Since the early 21st century modern imaging techniques like high-resolution computed tomography (μCT) reveal non-destructive insights into the mammalian skull. Furthermore, visualization software enables the virtual reconstruction of the tissues and additionally their morphometric analyses. However, the use of morphometric approaches on the nasal cavity is still scarce. Moreover, the turbinal skeleton is generally regarded as a unit, or the rostral respiratory part is compared to the caudal olfactory part; but the distinct olfactory turbinals have been considered only in a few studies.
The present study focuses on the highly diverse facial shape of the dog (Canis lupus familiaris) that evolved during domestication. Due to human-controlled breeding and care the natural selective pressure in prehistoric dogs has been replaced continually by artificial selection. As a consequence, harmful mutations on gene loci which e.g., control facial length growth got fixed within an extremely short time. According to veterinarian studies the turbinals of short snouted breeds continue their growth after the elongation of the facial bones has stopped prematurely. However, such investigations are based on low-resolution CT or MRT data and the morphological descriptions are vague. Referring to the elongation of the face in dolichocephalic breeds no former study has dealt with the detailed morphology of their turbinal skeleton so far.
The current study is based on comparative anatomical, morphometric, morphofunctional, and ontogenetic patterns of the dog’s turbinal skeleton. The 32 macerated skulls and four histological serial sections represent eleven breeds which cover different snout lengths (brachycephalic, mesaticephalic, dolichocephalic; according to two length indices), functional groups (scent hound, sighthound, companion/toy), and breeding histories (ancient pure-breeding associated with an unchanged appearance, modern time fashion breeding). The nasal cavity of the selected skulls was μCT-scanned and virtual 3D models of the turbinal skeleton were reconstructed. The breeds have been compared with each other in their number of olfactory turbinals, in the morphology of all turbinals and the lamina semicircularis as well as in their morphometrics and ontogeny. Based on morphological and ontogenetic patterns a new terminology of the interturbinals was established. The morphometric data covers the measurement of the relative turbinal surface area (IAT) and the calculation of the surface density (SDEN) and the turbinal complexity (TC). For the latter parameter a new morphometric approach was developed. For the ontogenetic comparison histological serial sections of perinatal dog stages have been consulted. As the dog’s ancestor macerated skulls of three adult Eurasian wolves (Canis lupus lupus) function for outgroup comparison and represent the grundplan with which the breeds are compared.
The results support former studies concerning a species-specific number of the fronto- and ethmoturbinals: in the Eurasian wolf and all postnatal dogs under study three ethmoturbinals and three frontoturbinals are observed. Additionally, two types of interturbinals are distinguished, namely four prominent interturbinals which are present in nearly all individuals and show a homologous pattern, and a variable number of additional interturbinals which differ in their shape among the dogs. Generally, longer snouted breeds have more additional interturbinals, so the total number of olfactory turbinals is increased to a maximum of 16 in the borzoi, whereas several short snouted breeds have only nine olfactory turbinals due to the loss of additional interturbinals and one prominent interturbinal. Regarding ontogeny the growth of the respiratory and the olfactory turbinals and the lamina semicircularis is highly associated with the growth of the facial bones after birth. As the viscerocranium of brachycephalic breeds is subjected to a postnatal growth inhibition the ethmoidal region stops growing prematurely, too. The turbinals of both functional parts develop less accessory lamellae that results in the reduction of the three morphometric parameters IAT, SDEN, and TC. The increase of all these three parameters with increasing snout length proves a correlation between both variables in the maxilloturbinal, all olfactory turbinals, and the lamina semicircularis in the dog. With the help of the perinatal dog stages plesiomorphic patterns which are present in all adult specimens (e.g., separation of ethmoturbinal I into two laminae, the presence of the uncinate process) were distinguished from less established morphological traits which get preferably reduced in association with brachycephaly (e.g., the anterior process of the posterior lamina of ethmoturbinal I, the caudal processes of frontoturbinal 1 and 2 within the frontal sinus due to the latter’s reduction). Obviously, the driving mechanism behind these and further variations are mutations on gene loci which control ontogenetic processes: the in other studies already described postnatal growth inhibition in the dermal bones of the midface of brachycephalic breeds seems to have a similar effect on the ethmoidal region. The results of the present study serve as basis for the evaluation how far the bony turbinals’ morphology, morphometrics, and ontogeny might be associated with physiological, genetic, neurological, and phylogenetic patterns. Additionally, the growth patterns of the hard tissues need to be compared to those of the soft tissues (i.e. the nasal epithelium).
There seems to be a wide agreement in critical geographic thought that Hegel is dead, as to end up with Hegel’s idealism serves to be the starting point for the materialist project of critical geographies. This paper aims to call this starting point into question by confronting Henri Lefebvre with Slavoj Žižek. While Lefebvre, one of the pioneers of materialist geographic thought, intensively worked on a metaphilosophical critique to open Hegel’s testament, Žižek’s Hegel supposed to pave the way for a new philosophical materialism. This paper seeks to claim that such a materialist Hegel not only survives the critical encounter of Lefebvre’s metaphilosophy, but also encourages us to inquire about the possibilities and consequences of a geographical turn to Hegel. What if there is a Hegel out there that geography has not even detected?
There is a broad consensus that psychoanalytic theory cannot offer an account to further engage with the ontological turn toward the object that human sciences face today. In particular, the structuralist side of psychoanalysis, most prominently promoted by Jacques Lacan, is supposed to be unable to grasp an object independently from the subject. Against this background, it is no surprise that ‘object-oriented’ geographers ignore psychoanalytic theory. My aim is to investigate the interstices between the object-oriented turn and Lacanian psychoanalysis. I argue that the critiques miss a crucial aspect of Lacan’s ontology: he does not question that there are objects located ‘out there’, but rather adds that psychoanalysis engages with another object whose location remains uncertain. I follow Lacan’s most important invention, the object a, to argue that this object is crucial to understanding the ontology of Lacan as an ‘object-disoriented’ ontology. While object-oriented approaches in cultural geography give ontological priority to the material conditions of existence, Lacanian ontology allows us to understand how material objects become spectralized through an immaterial surplus. To substantiate this claim, I explore the role of anxiety with regard to the Sathorn Unique Tower, an abandoned skyscraper sitting in the middle of Bangkok. Widely known as the ‘Ghost Tower’, this ruin is internationally considered to be haunted. By focusing on a movie and an interview about the Ghost Tower as well as my own ethnographic observation of it, I not only explore the topological dimension of the ghost but also demonstrate that it is precisely the impossibility of localization that enables an object to disorientate the subject.
Im Rahmen einer angewandten kritischen Geographie beschäftigen wir uns in unserer Masterarbeit mit Realen Utopien auf Quartiersebene und zeigen, dass eine alternative Neuausrichtung der Stadtplanung und -entwicklung nötig und möglich ist. Die Grundlage dafür bildet eine kritische Auseinandersetzung mit dem Begriff der Utopie und der Ebene des Quartiers. Das städtische Quartier bildet einen Möglichkeitsraum, einen space of hope (Harvey 2000), in dem Alternativen jenseits kapitalistischer Verwertungsinteressen praktiziert und gelebt werden können. Diesen Möglichkeitsraum gilt es vielfältig zu gestalten und gegenwärtigen, neoliberalen Stadtentwicklungs-paradigmen Reale Utopien(Wright 2017a) entgegenzustellen. Dabei stellt sich die Frage: Welche Gegenentwürfe zu aktuell herrschenden Paradigmen in der Stadtentwicklung zeigen uns Wege aus der Alternativlosigkeit und hin zu einer solidarischen Praxis auf Quartiersebene?Für die Beantwortung dieser Frage werden potentielle und bereits existierende Reale Utopien identifiziertund analysiert. In dieser Analyse werden Instrumente, Forderungen und Strategien herausgearbeitet, derer es Bedarf um Risse im kapitalistischem System auszuweiten, zu verteidigen und zu verstetigen. Die Ergebnisse lassen sich unter den Begriffen der Solidarität, Dekommodifi-zierung, Demokratisierung und Vergesellschaftung zusammenfassen. Sie sind die zentralen Bedin-gungen, die für die Verwirklichung Realer Utopien und damit für gesellschaftliche Transformation, entscheidend sind. Darauf basierendwird ein Kompass für ein solidarisches Quartier erarbeitet.