@misc{BeckerSchallerKeuler, author = {Becker, Andreas and Schaller, Eberhard and Keuler, Klaus}, title = {Continuous four-dimensional source attribution for the Berlin area during two days in July 1994. Part II: Sensitivy studies}, abstract = {The multiple nested three-dimensional (3D) mesoscale Eulerian grid point model MM5 is directly coupled with a Lagrangian particle trajectory model in order to perform a four-dimensional source attribution for the area of Berlin based on the horizontal distribution of the import probability density (IPD).}, language = {en} } @inproceedings{SeeligHarlanderBorciaetal., author = {Seelig, Torsten and Harlander, Uwe and Borcia, Ion-Dan and Scurtu, Nicoleta and Egbers, Christoph and Klein, Marten and Ghasemi, Abouzar and Will, Andreas and Schaller, Eberhard}, title = {Inertial waves in rotating cylindrical annulus: theory, experiment and simulations}, series = {Book of abstracts, 9th European Fluid Mechanics Conference (EFMC), 9-13 September, Rome, Italy}, booktitle = {Book of abstracts, 9th European Fluid Mechanics Conference (EFMC), 9-13 September, Rome, Italy}, language = {en} } @inproceedings{SeeligBorciaKleinetal., author = {Seelig, Torsten and Borcia, Ion-Dan and Klein, Marten and Ghasemi, Abouzar and Will, Andreas and Egbers, Christoph and Schaller, Eberhard and Harlander, Uwe}, title = {Inertial waves and wave attractors in a rotating annulus with inner or outer cylinder libration}, series = {European Geosciences Union (EGU), 10th General Assembly, Vienna, Austria, 07 - 12 April 2013}, booktitle = {European Geosciences Union (EGU), 10th General Assembly, Vienna, Austria, 07 - 12 April 2013}, language = {en} } @misc{KleinSeeligKurganskyetal., author = {Klein, Marten and Seelig, Torsten and Kurgansky, Michael V. and Ghasemi, Abouzar and Borcia, Ion-Dan and Will, Andreas and Schaller, Eberhard and Egbers, Christoph and Harlander, Uwe}, title = {Inertial wave excitation and focusing in a liquid bounded by a frustum and a cylinder}, series = {Journal of Fluid Mechanics}, journal = {Journal of Fluid Mechanics}, number = {vol. 751}, issn = {1750-6859}, doi = {10.1017/jfm.2014.304}, pages = {255 -- 297}, abstract = {The mechanism of localized inertial wave excitation and its efficiency is investigated for an annular cavity rotating with Ω0 . Meridional symmetry is broken by replacing the inner cylinder with a truncated cone (frustum). Waves are excited by individual longitudinal libration of the walls. The geometry is non-separable and exhibits wave focusing and wave attractors. We investigated laboratory and numerical results for the Ekman number E ≈ 10-6. inclination α = 5.71◦ and libration amplitudes ε 0.2 within the inertial wave band 0 < ω < 2Ω0 . Under the assumption that the inertial waves do not essentially affect the boundary-layer structure, we use classical boundary-layer analysis to study oscillating Ekman layers over a librating wall that is at an angle α = 0 to the axis of rotation. The Ekman layer erupts at frequency ω = f∗, where f∗ ≡ 2Ω0 sin α is the effective Coriolis parameter in a plane tangential to the wall. For the selected inclination this eruption occurs for the forcing frequency ω/Ω0 = 0.2. For the librating lids eruption occurs at ω/Ω0 = 2. The study reveals that the frequency dependence of the total kinetic energy Kω of the excited wave field is strongly connected to the square of the Ekman pumping velocity wE (ω) that, in the linear limit, becomes singular when the boundary layer erupts. This explains the frequency dependence of non-resonantly excited waves. By the localization of the forcing, the two configurations investigated, (i) frustum libration and (ii) lids together with outer cylinder in libration, can be clearly distinguished by their response spectra. Good agreement was found for the spatial structure of low-order wave attractors and periodic orbits (both characterized by a small number of reflections) in the frequency windows predicted by geometric ray tracing. For 'resonant' frequencies a significantly increased total bulk energy was found, while the energy in the boundary layer remained nearly constant. Inertial wave energy enters the bulk flow via corner beams, which are parallel to the characteristics of the underlying Poincar{\´e} problem. Numerical simulations revealed a mismatch between the wall-parallel mass fluxes near the corners. This leads to boundary-layer eruption and the generation of inertial waves in the corners.}, language = {en} } @incollection{Schaller, author = {Schaller, Eberhard}, title = {Simulation des gegenw{\"a}rtigen und zuk{\"u}nftigen Regionalklimas von Brandenburg}, series = {Globaler Wandel und regionale Entwicklung}, booktitle = {Globaler Wandel und regionale Entwicklung}, editor = {H{\"u}ttl, Reinhard F. and Emmermann, Rolf and Germer, Sonja and Naumann, Matthias and Bens, Oliver}, publisher = {Springer}, address = {Berlin [u.a.]}, doi = {10.1007/978-3-642-19478-8}, pages = {37 -- 142}, language = {de} } @incollection{AnSchaller, author = {An, Ni and Schaller, Eberhard}, title = {Issues and Opportunities for Implementation of VSS in China}, series = {Voluntary Standard Systems}, booktitle = {Voluntary Standard Systems}, editor = {Schmitz-Hoffmann, Carsten and Schmidt, Michael and Hansmann, Berthold and Palekhov, Dmitry}, publisher = {Springer}, address = {Berlin [u.a.]}, isbn = {978-3-642-35715-2}, doi = {10.1007/978-3-642-35716-9}, pages = {243 -- 251}, language = {en} } @inproceedings{KeulerBlockSchaller, author = {Keuler, Klaus and Block, Alexander and Schaller, Eberhard}, title = {Assessment of quality and uncertainty in regional climate simulations}, series = {Extended abstracts of a WMO/WCRP-sponsored Regional-Scale Climate Modelling Workshop, high-resolution climate modelling, assessment, added value and applications, Lund, Sweden, 29 March-2 April 2004}, booktitle = {Extended abstracts of a WMO/WCRP-sponsored Regional-Scale Climate Modelling Workshop, high-resolution climate modelling, assessment, added value and applications, Lund, Sweden, 29 March-2 April 2004}, editor = {B{\"a}rring, Lars and Laprise, Rene}, publisher = {Lund University}, address = {Lund, Sweden}, pages = {68 -- 69}, language = {en} } @inproceedings{KeulerRadtkeSchaller, author = {Keuler, Klaus and Radtke, Kai S. and Schaller, Eberhard}, title = {Effect of internal variability on regional climate change projections}, series = {2nd International Lund RCM Workshop : 21st Century Challenges in Regional-scale Climate Modelling, Lund University, Sweden, 4-8 May 2008, workshop proceedings}, booktitle = {2nd International Lund RCM Workshop : 21st Century Challenges in Regional-scale Climate Modelling, Lund University, Sweden, 4-8 May 2008, workshop proceedings}, editor = {Rockel, Burkhardt and B{\"a}rring, Lars and Reckermann, Marcus}, publisher = {International BALTEX Secretariat}, address = {GKSS Forschungszentrum Geesthacht}, pages = {132 -- 133}, language = {en} } @inproceedings{KleinBorciaEgbersetal., author = {Klein, Marten and Borcia, Ion-Dan and Egbers, Christoph and Ghasemi, Abouzar and Harlander, Uwe and Kurgansky, Michael V. and Schaller, Eberhard and Seelig, Torsten and Will, Andreas}, title = {Inertial Waves and Wave Excitation Mechanisms in Annular Cavities: Simulations, Experiments and Theory}, series = {European Turbulence Conference ETC14, Lyon, 2013}, booktitle = {European Turbulence Conference ETC14, Lyon, 2013}, pages = {2}, language = {en} } @inproceedings{BrueckPohleKeuleretal., author = {Br{\"u}ck, Yasemine and Pohle, Ina and Keuler, Klaus and Schaller, Eberhard and Hinz, Christoph}, title = {Do mining lakes in the Lusatian Lignite mining region (Eastern Germany) affect regional precipitation patterns?}, series = {European Geosciences Union, General Assembly 2016, Vienna, Austria}, booktitle = {European Geosciences Union, General Assembly 2016, Vienna, Austria}, publisher = {European Geophysical Society}, address = {Katlenburg-Lindau}, abstract = {Due to the flooding of former open-pit mines, Europe's largest artificial lake district is created in Eastern Germany. Between 1990 and 2006 more than 80 km² of new lakes have already been formed. These large-scale land cover changes may impact regional meteorological characteristics, therefore it is of interest, whether effects of the mining lakes can already be observed. We especially focus on whether the evaporation from the mining pit lakes leads to a higher precipitation on their lee side. To detect changes in the precipitation patterns, we analysed daily precipitation data (1980-2014) of 25 stations in an area of 10 000 km² widely around the lake district. Under the assumption that the influences of the lakes should be detectable either directly as trends in the observed data or as a deviation from a general measure for precipitation we combined statistical tests and principal component analysis (PCA). We applied pre-whitening Mann-Kendall tests to detect precipitation trends and Mann-Whitney tests to detect differences between split samples (before and after the flooding of most of the lakes). The PCA was applied based on the correlation matrix of daily precipitation at the different stations. As the daily precipitation can sufficiently be explained by the first five principal components, the recombination of these five principal components was used as a general measure of precipitation in the region. By regression trees (random forests) a relation between the eigenvectors of the first five principal components and physiogeographic characteristics of the stations (e.g. altitude) was shown. Both the observed data and the deviations between the measurements and the recombination of the first five principal components showed divergent trends with high spatial variability and also interannual variability, but a pattern consistent with the lee side of the lake could not be detected. Therefore, it has been demonstrated that the emerging lakes had no influence on the daily precipitation at the stations considered in this study. This may be explained by the coarse spatial and also temporal resolution of precipitation measurements. Still, the approach presented here can be applied to (i) detect changes in the spatial pattern of climate variables by a combination of statistical tests and PCA and (ii) to analyse the relationships between such changes and physiogeographic characteristics by regression trees.}, language = {en} } @misc{GhasemiKleinHarlanderetal., author = {Ghasemi, Abouzar and Klein, Marten and Harlander, Uwe and Kurgansky, Michael V. and Schaller, Eberhard and Will, Andreas}, title = {Mean flow generation by G{\"o}rtler vortices in a rotating annulus with librating side walls}, series = {Physics of Fluids}, volume = {28}, journal = {Physics of Fluids}, number = {056603}, doi = {10.1063/1.4948406}, pages = {1 -- 23}, abstract = {Time periodic variation of the rotation rate of an annulus induces in supercritical regime an unstable Stokes boundary layer over the cylinder side walls, generating G{\"o}rtler vortices in a portion of a libration cycle as a discrete event. Numerical results show that these vortices propagate into the fluid bulk and generate an azimuthal mean flow. Direct numerical simulations of the fluid flow in an annular container with librating outer (inner) cylinder side wall and Reynolds-averaged Navier-Stokes (RANS) equations as diagnostic equations are used to investigate generation mechanism of the retrograde (prograde) azimuthal mean flow in the bulk. First, we explain, phenomenologically, how absolute angular momentum of the bulk flow is mixed and changed due to the propagation of the G{\"o}rtler vortices, causing a new vortex of basin size. Then we investigate the RANS equations for intermediate time scale of the development of the G{\"o}rtler vortices and for long time scale of the order of several libration periods. The former exhibits sign selection of the azimuthal mean flow. Investigating the latter, we predict that the azimuthal mean flow is proportional to the libration amplitude squared and to the inverse square root of the Ekman number and libration frequency and then confirms this using the numerical data. Additionally, presence of an upscale cascade of energy is shown, using the kinetic energy budget of fluctuating flow.}, language = {en} } @misc{BlockKeulerSchaller, author = {Block, Alexander and Keuler, Klaus and Schaller, Eberhard}, title = {Impacts of anthropogenic heat on regional climate patterns}, series = {Geophysical Research Letters}, volume = {31}, journal = {Geophysical Research Letters}, number = {12}, doi = {10.1029/2004GL019852}, pages = {4}, abstract = {[1] Four different simulations of a winter period in Central Europe are carried out to investigate the principle effect of anthropogenic heat release from the highly industrialized and populated Ruhrarea region (Germany) on regional climate conditions. The results reveal a permanent warming due to anthropogenic heat emissions over affected areas ranging from 0.15 K over land area with an additional 2 W m-2 anthropogenic heat flux up to 0.5 K over the Ruhrarea with additional 20 W m-2 anthropogenic heat flux. The temperature effects induced by anthropogenic heat not only depend on the amount of added heat but also on orographical factors. No significant variations are found for precipitation.}, language = {en} } @inproceedings{TsonkovaFreeseBoehmetal., author = {Tsonkova, Penka and Freese, Dirk and B{\"o}hm, Christian and Quinkenstein, Ansgar and Schaller, Eberhard}, title = {Benefits provided by silvoarable agroforestry systems in the temperate region: a review}, series = {Proceedings of the International Workshop on Agroforestry - Ecological Benefits of Agroforestry, 15-17 June 2011, Cottbus, Germany}, booktitle = {Proceedings of the International Workshop on Agroforestry - Ecological Benefits of Agroforestry, 15-17 June 2011, Cottbus, Germany}, editor = {Freese, Dirk and Pittruff, N. and Quinkenstein, Ansgar and B{\"o}hm, Christian}, pages = {S. 29}, language = {en} } @misc{TsonkovaQuinkensteinBoehmetal., author = {Tsonkova, Penka and Quinkenstein, Ansgar and B{\"o}hm, Christian and Freese, Dirk and Schaller, Eberhard}, title = {Ecosystem services assessment tool for agroforestry (ESAT-A): Anapproach to assess selected ecosystem services provided by alleycropping systems}, series = {Ecological Indicators}, journal = {Ecological Indicators}, number = {45}, doi = {10.1016/j.ecolind.2014.04.024}, pages = {285 -- 299}, language = {en} }