2018, Grinat, Michael, Epping, Dieter, Meyer, Robert, Szymkiewicz, Adam, Sadurski, A., Jaworska-Szulc, B.

In September 2009 two newly developed vertical electrode systems were installed in boreholes in the water catchment areas Waterdelle and Ostland at the North Sea island Borkum to monitor possible changes of the transition zone between the freshwater lens and the underlying saltwater. The vertical electrode systems, which were both installed between 44 m and 65 m below ground level, are used for geoelectrical multi-electrode measurements carried out automatically several times per day; the measurements are still ongoing. The whole system consisting of a vertical electrode system in a borehole and the measuring unit at ground level is called SAMOS (Saltwater Monitoring System). At both locations the data show a clear resistivity decrease that indicates the transition zone between freshwater and saltwater. The depth of the transition zone as well as the kind of resistivity decrease is very stable since 2010. Temporal changes are visible if single depths are considered. In 2015 Miriam Ibenthal used a vertical 2D density-dependent groundwater flow model to explain the long-term resistivity measurements and showed that the temporal changes at CLIWAT 2 (Ostland) could be explained by variations of the groundwater level, changing groundwater recharge rates and changing pumping rates of the nearby located drinking water supply wells.

2018, Schneider, A., Zhao, H., Wolf, J., Logashenko, D., Reiter, S., Howahr, M., Eley, M., Gelleszun, M., Wiederhold, H., Szymkiewicz, Adam, Sadurski, A., Jaworska-Szulc, B.

A 3d regional density-driven flow model of a heterogeneous aquifer system at the German North Sea Coast is set up within the joint project NAWAK (“Development of sustainable adaption strategies for the water supply and distribution infrastructure on condition of climatic and demographic change”). The development of the freshwater-saltwater interface is simulated for three climate and demographic scenarios. Groundwater flow simulations are performed with the finite volume code d3f++ (distributed density driven flow) that has been developed with a view to the modelling of large, complex, strongly density-influenced aquifer systems over long time periods.

2013, Grunwald, R., Das, S.K., Debroy, A., McGlynn, E., Messaoudi, H.

Nonlinear excitation mechanisms of plasmons and their influence on femtosecond-laser induced sub-wavelength ripple generation on dielectric and semiconducting transparent materials are discussed. The agreement of theoretical and experimental data indicates the relevance of the model.

2018, Zhukavin, R.Kh., Kovalevsky, K.A., Tsyplenkov, V.V., Pavlov, S.G., Hübers, H-W., Choporova, Yu.Yu., Knyazev, B.A., Klopf, J.M., Redlich, B., Abrosimov, N.V., Astrov, Yu.A., Shastin, V.N., Silaev, A.A.

This article has no abstract.

2018, Wiederhold, Helga, Scheer, Wolfgang, Kirsch, Reinhard, Azizur Rahman, M., Ronczka, Mathias, Szymkiewicz, Adam, Sadurski, A., Jaworska-Szulc, B.

Climate change will result in rising sea level and, at least for the North Sea region, in rising groundwater table. This leads to a new balance at the fresh–saline groundwater boundary and a new distribution of saltwater intrusions with strong regional differentiations. These effects are investigated in several research projects funded by the European Union and the German Federal Ministry of Education and Research (BMBF). Objectives and some results from the projects TOPSOIL and go-CAM are presented in this poster.

2018, Rahman, Mohammad Azizur, González, Eva, Wiederhold, Helga, Deus, Nico, Elbracht, Jörg, Siemon, Bernhard, Szymkiewicz, Adam, Sadurski, A., Jaworska-Szulc, B.

In this study, interdisciplinary approaches are considered to characterize the coastal zone aquifer of the Elbe-Weser region in the North of Lower Saxony, Germany. Geological, hydrogeological, geochemical and geophysical information have been considered to analyze the current status of the aquifers. All the information collectively states that the salinity distribution in the subsurface is heterogeneous both horizontally and vertically. Early age flooding also contributed to this heterogeneity. No general classification of groundwater quality (according to some piper diagrams) could be identified. Helicopter-borne electro-magnetic data clearly show the presence of freshwater reserves below the sea near the west coast. Groundwater recharge largely happens in the moraine ridges (west side of the area) where both the surface elevation and the groundwater level are high. Consequently, submarine groundwater discharge occurs from the same place. All these information will facilitate to develop the planned density driven groundwater flow and transport model for the study area.

2015, Amaya, Jorge, Musset, Sophie, Andersson, Viktor, Diercke, Andrea, Höller, Christian, Iliev, Sergiu, Juhász, Lilla, Kiefer, René, Lasagni, Riccardo, Lejosne, Solène, Madi, Mohammad, Rummelhagen, Mirko, Scheucher, Markus, Sorba, Arianna, Thonhofer, Stefan

An accurate forecast of flare and coronal mass ejection (CME) initiation requires precise measurements of the magnetic energy buildup and release in the active regions of the solar atmosphere. We designed a new space weather mission that performs such measurements using new optical instruments based on the Hanle and Zeeman effects. The mission consists of two satellites, one orbiting the L1 Lagrangian point (Spacecraft Earth, SCE) and the second in heliocentric orbit at 1AU trailing the Earth by 80° (Spacecraft 80, SC80). Optical instruments measure the vector magnetic field in multiple layers of the solar atmosphere. The orbits of the spacecraft allow for a continuous imaging of nearly 73% of the total solar surface. In-situ plasma instruments detect solar wind conditions at 1AU and ahead of our planet. Earth-directed CMEs can be tracked using the stereoscopic view of the spacecraft and the strategic placement of the SC80 satellite. Forecasting of geoeffective space weather events is possible thanks to an accurate surveillance of the magnetic energy buildup in the Sun, an optical tracking through the interplanetary space, and in-situ measurements of the near-Earth environment.

2017, Michel, Eric, Belkacem, Kevin, Samadi, Reza, de Assis Peralta, Raphael, Renié, Christian, Abed, Mahfoudh, Lin, Guangyuan, Christensen-Dalsgaard, Jørgen, Houdek, Günter, Handberg, Rasmus, Gizon, Laurent, Burston, Raymond, Nagashima, Kaori, Pallé, Pere, Poretti, Ennio, Rainer, Monica, Mistò, Angelo, Panzera, Maria Rosa, Roth, Markus, Monteiro, Mário J. P. F. G., Cunha, Margarida S., Ferreira, João Miguel T. S.

The growing amount of seismic data available from space missions (SOHO, CoRoT, Kepler, SDO,…) but also from ground-based facilities (GONG, BiSON, ground-based large programmes…), stellar modelling and numerical simulations, creates new scientific perspectives such as characterizing stellar populations in our Galaxy or planetary systems by providing model-independent global properties of stars such as mass, radius, and surface gravity within several percent accuracy, as well as constraints on the age. These applications address a broad scientific community beyond the solar and stellar one and require combining indices elaborated with data from different databases (e.g. seismic archives and ground-based spectroscopic surveys). It is thus a basic requirement to develop a simple and effcient access to these various data resources and dedicated tools. In the framework of the European project SpaceInn (FP7), several data sources have been developed or upgraded. The Seismic Plus Portal has been developed, where synthetic descriptions of the most relevant existing data sources can be found, as well as tools allowing to localize existing data for given objects or period and helping the data query. This project has been developed within the Virtual Observatory (VO) framework. In this paper, we give a review of the various facilities and tools developed within this programme. The SpaceInn project (Exploitation of Space Data for Innovative Helio- and Asteroseismology) has been initiated by the European Helio- and Asteroseismology Network (HELAS).

2013, Rosenfeld, A., Höhm, S., Bonse, J., Krüger, J.

The dynamics of the formation of laser-induced periodic surface structures (LIPSS) on fused silica upon irradiation with linearly polarized fs-laser pulses (50 fs pulse duration, 800 nm center wavelength) is studied experimentally using a double pulse experiment with cross polarized pulse sequences and a trans illumination femtosecond time-resolved (0.1 ps - 1 ns) pump-probe diffraction approach. The results in both experiments confirm the importance of the ultrafast energy deposition and the laser-induced free-electron plasma in the conduction band of the solids for the formation of LIPSS.

2018, Veselovskii, Igor, Goloub, Philippe, Podvin, Thierry, Tanre, Didier, Ansmann, Albert, Korenskiy, Michail, Borovoi, Anatoli, Hu, Qiaoyun, Bovchaliuk, Valentin, Whiteman, David N., Nicolae, D., Makoto, A., Vassilis, A., Balis, D., Behrendt, A., Comeron, A., Gibert, F., Landulfo, E., McCormick, M.P., Senff, C., Veselovskii, I., Wandinger, U.

Lidar sounding is used for the analysis of possible contribution of the corner reflection (CR) effect to the total backscattering in case of ice crystals. Our study is based on observations of mixed phase clouds performed during the SHADOW campaign in Senegal. Mie-Raman lidar allows measurements at 355 nm and 532 nm at 43 dg. off-zenith angle, so the extinction and backscattering Ångström exponents can be evaluated. In some measurements we observed the positive values of backscattering Ångström exponent, which can be attributed to the corner reflection by horizontally oriented ice plates.