Studying the City Plume of Berlin on 20 July 1998 with Three Different Modelling Approaches

In this paper we try to identify and describe the specifics of the Berlin city plume characterised by a zone of enhanced photochemical activity downwind of the urban area, where the major emissions of ozone precursors (NO_x and VOC) take place. Two Eulerian CTM systems (EURAD and REM3/CALGRID) and one Euler–Lagrangian model (LaMM5) are applied to thearea of Berlin/Brandenburg to investigate the processes involved in the evolution of the Berlin plume inherent to the models. The study focuses on 20 July 1998,the first special observation period (SOP) during BERLIOZ. The examination includes (1) the role of turbulence and transport and the role of mass flux to the surface during the evolution of the plume, (2) the import situation of the ground based measurement sites, (3)the terms of the ozone budget equation and their contribution to precursor distribution and ozone formation, (4) the substructures of the plume defined by its chemical regimes. Main results show that the complex meteorological conditions during this SOP with considerable turbulent transports demand an Euler–Lagrangian approach to determine the source receptor relationshipsfor the ground based measurement sites. These relations reveal that only a minor part (5%) of the air approaching Pabstthum and the more downwind (north-western) stations origins from Berlin and that the mutual transport between all sites was limited. The latter result afflicts the joint interpretation of data from different stations because the presumption to measure the same air mass is violated in many cases for this SOP. The CTM results reveal that the local net production of ozone within the plume was controlled by transport ad chemical processes both owning the same importance but tending to counteract each other. At this SOP far distance sources of ozone precursors originating from the Bohemian basin did not interfere the Berlin city plume although they generally have the potential to do so.     

The development of forest damage — control and prognosis on the basis of remote sensing data

Forest damage can be caused by three types of stress which exercise their influence by predisposing, causative and contributory factors. Predisposing factors, above all permanent immision stress, cause the general diminishing of the trees' vitality. Causative fators such as long and extreme periods of dryness cause a fast and evident deterioration of the forest stand, contributory factors as eg pest attacks cause their mortification. When using remote sensing data to monitor the development of forest damage it is necessary therefore not only to pay attention to spectral signatures characterizing the degree of green space and thus the information of the canopy but also to spectral signs showing the water supply of the stands. This has not been done so far though nowadays the necessary multispectral satellite data are on regular offer. For this reason it may be suggested that the existing possibilities to predict the development of forest damage on the basis of remote sensing data have not yet been fully used.In order to examine these possibilities, in the environs of Berlin, ie in the east and south of the Land of Brandenburg both the vegetation index which has been known from literature for a long time and an index for the difference in remission identifying the water bands in the short-wave infrared have been calculated on the basis of Landsat-TM data. A multi-temporal comparison shows that despite the bad conditions of the forest in 1991 on the test site located north-east of Berlin due to a relatively good water supply in that year the pine forest damage had not progressed in 1992. This allows to draw the conclusion that at least in the pine forests of the East German interior lowland the development of forest damage is essentially determined by dryness stress. In this way on the basis of 1992 Landsat-TM data there was not only an inventory made of the actual condition of the forest on the east and south-east of the Land of Brandenburg but also trends of damage progress shown. The damage classification of pine stands be completed by a prognosis as to the development of damage.     

An empirical Redlich-Kwong-type equation of state for water to 1,000 °C and 200 Kbar

An empirically derived Redlich-Kwong type of equation of state (ERK) is proposed for H₂O, expressing a, the term related to the attraction between the molecules, as a pressure-independent function of temperature, and b, the covolume, as a temperature-independent function of pressure. The coefficients of a(T) and b(P) were derived by least squares non-linear regression, using P-V-T data given by Burnham et al. (1969b) and Rice and Walsh (1957) in conjunction with more precise recent data obtained by Tanishita et al. (1976), Hilbert (1979) and Schmidt (1979): $$a(T) = 1.616 x 10^8 - 4.989 x 10^4 T - 7.358 x 10^9 T^{ - 1} $$ and $$ = \frac{{1 + 3.4505x 10^{--- 4} P + 3.8980x 10^{--- 9} P^2 - 2.7756x 10^{--- 15} P^3 }}{{6.3944x 10^{--- 2} + 2.3776x 10^{--- 5} + 4.5717x 10^{--- 10} P^2 }}$$ , where T is expressed in Kelvin and P in bars. The ERK works very well at upper mantle conditions, at least up to 200 kbar and 1,000 °C. At subcritical conditions and those somewhat above the critical point, it still reproduces the molar Gibbs energy, \(\tilde G_{{\text{H}}_{\text{2}} {\text{O}}} \) , with a maximum deviation of 400 joules. Thus, for the purpose of calculation of geologically interesting heterogeneous equilibria, it predicts the thermodynamic properties of H₂O well enough. The values of molar volume, \(\tilde V_{{\text{H}}_{\text{2}} {\text{O}}} \) , and \(\tilde G_{{\text{H}}_{\text{2}} {\text{O}}} \) are tabulated in the appendix over a considerable P-T range. A FORTRAN program generating these functions as well as a FORTRAN subroutine for calculating the fugacity values, \(f_{{\text{H}}_{\text{2}} {\text{O}}} \) for incorporation into existing programs, are available upon request.     

Simulation of SH- and P-SV-wave propagation in fault zones

Seismic fault-zone (FZ) trapped waves provide a potentially high-resolution means for investigating FZ and earthquake properties. Seismic waves emitted within and travelling along low-velocity FZ layers may propagate many kilometres within the low-velocity structure associated with the fault. Waveform observation of FZ trapped waves can be modelled in terms of FZ layer velocities, thicknesses and attenuation coefficients. This can greatly improve the resolution of imaged FZ structure and microearthquake locations. At present, broad-band theoretical seismograms are restricted to plane-parallel layers of uniform properties. However, it is not clear how realistic these models are compared with actual fault structures which could, for example, flare outwards near the surface, have irregular boundaries, interior heterogeneities, etc. To address these interpretational uncertainties, we perform finite-difference simulations for irregular FZ geometries and non-uniform material properties within the layers. The accuracy of the numerical solutions are verified by comparison with the analytical solution of Ben-Zion & Aki (1990) for plane-parallel structures. Our main findings are: (1) FZs can widen at the ctustal surface only slightly modifying the trapped waves; (2) velocity variations with depth destroy trapped wave propagation at all wavelengths; (3) FZ trapped waves can be obscured by the presence of a low-velocity surface layer; (4) models with short-scale random structures suggest that trapped waves average out irregular FZ geometries, and hence can be effectively modelled by average-property plane-layered media for the observed range of wavelengths.     

Paläomagnetische Komplexuntersuchungen an Eruptiv- und Sedimentgesteinen des Böhmischen Massivs

Summary Complex methods, used at Potsdam since 1960 [4, 5, 6]³), nowadays are successfully tried for paleomagnetic studies also. Results in this direction in the following are discussed in detail.     

Petrographic investigations in cemeteries in Dresden: a scientific view on the tombstone inventory including historic and cultural aspects

Cemeteries give evidence for a continuous change in sepulchral culture and provide insights into the application of characteristical rock materials used for tombstones during different times. Four selected cemeteries in Dresden (the Eliasfriedhof/Elias Cemetery, the Trinitatisfriedhof/Trinity Cemetery, the Johannisfriedhof/Johannis Cemetery, and the Städtischer Urnenhain/Municipal Urn Grove), which are of considerable cultural and historical importance, have been investigated within an ongoing mapping project. First results of this project focussing on the tombstone inventory of the mentioned graveyards and thus the use of building and decoration stones therein between 1680 and 1945 are presented in this paper. It can be demonstrated that the choice, variety, and application of rock material depends on the infrastructure and transport possibilities, but is also strongly influenced by sepulchral cultural trends and the prevailing zeitgeist. Until the middle of the 19th century, nearly solely Elbe sandstone (from the area of the Elbsandsteingebirge/Elbe sandstone mountains), that was transported on the Elbe river by ship, is found as rock material for tombstones in Dresden cemeteries. Rapid construction and development of the railway network starting around 1840 improved the availability, at first, of regional rock material (e.g., from the Lausitz/Lusatia) and, later on, from about 1880, of national and international—especially European—rock material (e.g., from Franken/Franconia, France, Scandinavia). Furthermore, the Friedhofsreformbewegung/cemetery reform movement at the beginning of the 20th century, with its significant effect on the selection of rock types used for tombstones, marks another historical breakthrough.     

Geodetic methods to determine the relativistic redshift at the level of 10$$^{}$$ in the context of international timescales: a review and practical results

The frequency stability and uncertainty of the latest generation of optical atomic clocks is now approaching the one part in \(10^{18}\) level. Comparisons between earthbound clocks at rest must account for the relativistic redshift of the clock frequencies, which is proportional to the corresponding gravity (gravitational plus centrifugal) potential difference. For contributions to international timescales, the relativistic redshift correction must be computed with respect to a conventional zero potential value in order to be consistent with the definition of Terrestrial Time. To benefit fully from the uncertainty of the optical clocks, the gravity potential must be determined with an accuracy of about \(0.1\,\hbox {m}^{2}\,\hbox {s}^{-2}\), equivalent to about 0.01 m in height. This contribution focuses on the static part of the gravity field, assuming that temporal variations are accounted for separately by appropriate reductions. Two geodetic approaches are investigated for the derivation of gravity potential values: geometric levelling and the Global Navigation Satellite Systems (GNSS)/geoid approach. Geometric levelling gives potential differences with millimetre uncertainty over shorter distances (several kilometres), but is susceptible to systematic errors at the decimetre level over large distances. The GNSS/geoid approach gives absolute gravity potential values, but with an uncertainty corresponding to about 2 cm in height. For large distances, the GNSS/geoid approach should therefore be better than geometric levelling. This is demonstrated by the results from practical investigations related to three clock sites in Germany and one in France. The estimated uncertainty for the relativistic redshift correction at each site is about \(2 \times 10^{-18}\).     

Numerical Green’s function method:Application to quantifying ground motion variations of M7 earthquakes

The concept of "numerical Green’s functions" (NGF or Green’s function database) is developed. The basic idea is: a large seismic fault is divided into subfaults of appropriate size, for which synthetic Green’s functions at the surface (NGF) are calculated and stored. Consequently, ground motions from arbitrary kinematic sources can be simulated, rapidly, for the whole fault or parts of it by superposition. The target fault is a simplified, vertical model of the Newport-Inglewood fault in the Los Angeles basin. This approach and its functionality are illustrated by investigating the variations of ground motions (e.g. peak ground velocity and synthetic seismograms) due to the source complexity. The source complexities are considered with two respects: hypocenter location and slip history. The results show a complex behavior, with dependence of absolute peak ground velocity and their variation on source process directionality, hypocenter location, local structure, and static slip asperity location. We concluded that combining effect due to 3-D structure and finite-source is necessary to quan- tify ground motion characteristics and their variations. Our results will facilitate the earthquake hazard assessment projects.     

Solifluction meets vegetation: the role of biogeomorphic feedbacks for turf‐banked solifluction lobe development

Vegetation is an important factor influencing solifluction processes, while at the same time, solifluction processes and landforms influence species composition, fine‐scale distribution and corresponding ecosystem functioning. However, how feedbacks between plants and solifluction processes influence the development of turf‐banked solifluction lobes (TBLs) and their geomorphic and vegetation patterns is still poorly understood. We addressed this knowledge gap in a detailed biogeomorphic investigation in the Turtmann glacier foreland (Switzerland). Methods employed include geomorphic and vegetation mapping, terrain assessment with unmanned aerial vehicle (UAV) and temperature logging. Results were subsequently integrated with knowledge from previous geomorphic and ecologic studies into a conceptual model. Our results show that geomorphic and vegetation patterns at TBLs are closely linked through the lobe elements tread, risers and ridge. A conceptual four‐stage biogeomorphic model of TBL development with ecosystem engineering by the dwarf shrub Dryas octopetala as the dominant process can explain these interlinked patterns. Based on this model, we demonstrate that TBLs are biogeomorphic structures and follow a cyclic development, during which the role of their components for engineer and non‐engineer species changes. Our study presents the first biogeomorphic model of TBL development and highlights the applicability and necessity of biogeomorphic approaches and research in periglacial environments. Copyright © 2016 John Wiley & Sons, Ltd.     

Empirical assessment of obstruction adaptive elevation masks to mitigate site-dependent effects

GPS Solutions - Site-dependent effects are accuracy-limiting factors in static and kinematic GNSS-based positioning applications since they cannot be minimized using differential techniques. In...