TY  - JOUR
A1  - Ramiaramanantsoa, Tahina
A1  - Moffat, Anthony F. J.
A1  - Harmon, Robert
A1  - Ignace, R.
A1  - St-Louis, Nicole
A1  - Vanbeveren, Dany
A1  - Shenar, Tomer
A1  - Pablo, Herbert
A1  - Richardson, Noel D.
A1  - Howarth, Ian D.
A1  - Stevens, Ian R.
A1  - Piaulet, Caroline
A1  - St-Jean, Lucas
A1  - Eversberg, Thomas
A1  - Pigulski, Andrzej
A1  - Popowicz, Adam
A1  - Kuschnig, Rainer
A1  - Zoclonska, Elzbieta
A1  - Buysschaert, Bram
A1  - Handler, Gerald
A1  - Weiss, Werner W.
A1  - Wade, Gregg A.
A1  - Rucinski, Slavek M.
A1  - Zwintz, Konstanze
A1  - Luckas, Paul
A1  - Heathcote, Bernard
A1  - Cacella, Paulo
A1  - Powles, Jonathan
A1  - Locke, Malcolm
A1  - Bohlsen, Terry
A1  - Chené, André-Nicolas
A1  - Miszalski, Brent
A1  - Waldron, Wayne L.
A1  - Kotze, Marissa M.
A1  - Kotze, Enrico J.
A1  - Böhm, Torsten
T1  - BRITE-Constellation high-precision time-dependent photometry of the early O-type supergiant zeta Puppis unveils the photospheric drivers of its small- and large-scale wind structures
JF  - Monthly notices of the Royal Astronomical Society
N2  - From 5.5 months of dual-band optical photometric monitoring at the 1 mmag level, BRITE-Constellation has revealed two simultaneous types of variability in the O4I(n)fp star ζ Puppis: one single periodic non-sinusoidal component superimposed on a stochastic component. The monoperiodic component is the 1.78-d signal previously detected by Coriolis/Solar Mass Ejection Imager, but this time along with a prominent first harmonic. The shape of this signal changes over time, a behaviour that is incompatible with stellar oscillations but consistent with rotational modulation arising from evolving bright surface inhomogeneities. By means of a constrained non-linear light-curve inversion algorithm, we mapped the locations of the bright surface spots and traced their evolution. Our simultaneous ground-based multisite spectroscopic monitoring of the star unveiled cyclical modulation of its He ii λ4686 wind emission line with the 1.78-d rotation period, showing signatures of corotating interaction regions that turn out to be driven by the bright photospheric spots observed by BRITE. Traces of wind clumps are also observed in the He ii λ4686 line and are correlated with the amplitudes of the stochastic component of the light variations probed by BRITE at the photosphere, suggesting that the BRITE observations additionally unveiled the photospheric drivers of wind clumps in ζ Pup and that the clumping phenomenon starts at the very base of the wind. The origins of both the bright surface inhomogeneities and the stochastic light variations remain unknown, but a subsurface convective zone might play an important role in the generation of these two types of photospheric variability.
KW  - techniques: photometric
KW  - techniques: spectroscopic
KW  - stars: massive
KW  - stars: rotation
KW  - starspots
KW  - supergiants
KW  - stars: winds, outflows
Y1  - 2017
U6  - https://doi.org/10.1093/mnras/stx2671
SN  - 0035-8711
SN  - 1365-2966
VL  - 473
IS  - 4
SP  - 5532
EP  - 5569
PB  - Oxford Univ. Press
CY  - Oxford
ER  - 
TY  - JOUR
A1  - Böhm, Uwe
A1  - Kucken, M.
A1  - Hauffe, D.
A1  - Gerstengarbe, F. W.
A1  - Werner, P. C.
A1  - Flechsig, M.
A1  - Keuler, K.
A1  - Block, A.
A1  - Ahrens, W.
A1  - Nocke, T.
T1  - Reliability of regional climate model simulations of extremes and of long-term climate
N2  - We present two case studies that demonstrate how a common evaluation methodology can be used to assess the reliability of regional climate model simulations from different fields of research. In Case I, we focused on the agricultural yield loss risk for maize in Northeastern Brazil during a drought linked to an El-Nino event. In Case II, the present-day regional climatic conditions in Europe for a 10-year period are simulated. To comprehensively evaluate the model results for both kinds of investigations, we developed a general methodology. On its basis, we elaborated and implemented modules to assess the quality of model results using both advanced visualization techniques and statistical algorithms. Besides univariate approaches for individual near-surface parameters, we used multivariate statistics to investigate multiple near-surface parameters of interest together. For the latter case, we defined generalized quality measures to quantify the model's accuracy. Furthermore, we elaborated a diagnosis tool applicable for atmospheric variables to assess the model's accuracy in representing the physical processes above the surface under various aspects. By means of this evaluation approach, it could be demonstrated in Case Study I that the accuracy of the applied regional climate model resides at the same level as that we found for another regional model and a global model. Excessive precipitation during the rainy season in coastal regions could be identified as a major contribution leading to this result. In Case Study II, we also identified the accuracy of the investigated mean characteristics for near- surface temperature and precipitation to be comparable to another regional model. In this case, an artificial modulation of the used initial and boundary data during preprocessing could be identified as the major source of error in the simulation. Altogether, the achieved results for the presented investigations indicate the potential of our methodology to be applied as a common test bed to different fields of research in regional climate modeling
Y1  - 2004
SN  - 1561-8633
ER  - 
TY  - JOUR
A1  - Soliveres, Santiago
A1  - van der Plas, Fons
A1  - Manning, Peter
A1  - Prati, Daniel
A1  - Gossner, Martin M.
A1  - Renner, Swen C.
A1  - Alt, Fabian
A1  - Arndt, Hartmut
A1  - Baumgartner, Vanessa
A1  - Binkenstein, Julia
A1  - Birkhofer, Klaus
A1  - Blaser, Stefan
A1  - Blüthgen, Nico
A1  - Boch, Steffen
A1  - Böhm, Stefan
A1  - Börschig, Carmen
A1  - Buscot, Francois
A1  - Diekötter, Tim
A1  - Heinze, Johannes
A1  - Hölzel, Norbert
A1  - Jung, Kirsten
A1  - Klaus, Valentin H.
A1  - Kleinebecker, Till
A1  - Klemmer, Sandra
A1  - Krauss, Jochen
A1  - Lange, Markus
A1  - Morris, E. Kathryn
A1  - Müller, Jörg
A1  - Oelmann, Yvonne
A1  - Overmann, Jörg
A1  - Pasalic, Esther
A1  - Rillig, Matthias C.
A1  - Schaefer, H. Martin
A1  - Schloter, Michael
A1  - Schmitt, Barbara
A1  - Schöning, Ingo
A1  - Schrumpf, Marion
A1  - Sikorski, Johannes
A1  - Socher, Stephanie A.
A1  - Solly, Emily F.
A1  - Sonnemann, Ilja
A1  - Sorkau, Elisabeth
A1  - Steckel, Juliane
A1  - Steffan-Dewenter, Ingolf
A1  - Stempfhuber, Barbara
A1  - Tschapka, Marco
A1  - Türke, Manfred
A1  - Venter, Paul C.
A1  - Weiner, Christiane N.
A1  - Weisser, Wolfgang W.
A1  - Werner, Michael
A1  - Westphal, Catrin
A1  - Wilcke, Wolfgang
A1  - Wolters, Volkmar
A1  - Wubet, Tesfaye
A1  - Wurst, Susanne
A1  - Fischer, Markus
A1  - Allan, Eric
T1  - Biodiversity at multiple trophic levels is needed for ecosystem multifunctionality
JF  - Nature : the international weekly journal of science
Y1  - 2016
U6  - https://doi.org/10.1038/nature19092
SN  - 0028-0836
SN  - 1476-4687
VL  - 536
SP  - 456
EP  - +
PB  - Nature Publ. Group
CY  - London
ER  - 
TY  - JOUR
A1  - Verma, Meetu
A1  - Denker, Carsten
A1  - Böhm, F.
A1  - Balthasar, H.
A1  - Fischer, C. E.
A1  - Kuckein, Christoph
A1  - Gonzalez, N. Bello
A1  - Berkefeld, T.
A1  - Collados Vera, M.
A1  - Diercke, Andrea
A1  - Feller, A.
A1  - Gonzalez Manrique, Sergio Javier
A1  - Hofmann, A.
A1  - Lagg, A.
A1  - Nicklas, H.
A1  - Orozco Suarez, D.
A1  - Pator Yabar, A.
A1  - Rezaei, R.
A1  - Schlichenmaier, R.
A1  - Schmidt, D.
A1  - Schmidt, W.
A1  - Sigwarth, M.
A1  - Sobotka, M.
A1  - Solanki, S. K.
A1  - Soltau, D.
A1  - Staude, J.
A1  - Strassmeier, Klaus G.
A1  - Volkmer, R.
A1  - von der Lühe, O.
A1  - Waldmann, T.
T1  - Flow and magnetic field properties in the trailing sunspots of active region NOAA 12396
JF  - Astronomische Nachrichten = Astronomical notes
N2  - Improved measurements of the photospheric and chromospheric three-dimensional magnetic and flow fields are crucial for a precise determination of the origin and evolution of active regions. We present an illustrative sample of multi-instrument data acquired during a two-week coordinated observing campaign in August 2015 involving, among others, the GREGOR solar telescope (imaging and near-infrared spectroscopy) and the space missions Solar Dynamics Observatory (SDO) and Interface Region Imaging Spectrograph (IRIS). The observations focused on the trailing part of active region NOAA 12396 with complex polarity inversion lines and strong intrusions of opposite polarity flux. The GREGOR Infrared Spectrograph (GRIS) provided Stokes IQUV spectral profiles in the photospheric Si i.1082.7 nm line, the chromospheric He I lambda 1083.0 nm triplet, and the photospheric Ca I lambda 1083.9 nm line. Carefully calibrated GRIS scans of the active region provided maps of Doppler velocity and magnetic field at different atmospheric heights. We compare quick-look maps with those obtained with the " Stokes Inversions based on Response functions" (SIR) code, which furnishes deeper insight into the magnetic properties of the region. We find supporting evidence that newly emerging flux and intruding opposite polarity flux are hampering the formation of penumbrae, i.e., a penumbra fully surrounding a sunspot is only expected after cessation of flux emergence in proximity to the sunspots. (C) 2016 WILEY-VCH Verlag GmbH& Co.KGaA, Weinheim
KW  - Sun: magnetic fields
KW  - sunspots
KW  - methods: data analysis
KW  - techniques: polarimetric
KW  - techniques: spectroscopic
Y1  - 2016
U6  - https://doi.org/10.1002/asna.201612447
SN  - 0004-6337
SN  - 1521-3994
VL  - 337
SP  - 1090
EP  - 1098
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Allan, Eric
A1  - Bossdorf, Oliver
A1  - Dormann, Carsten F.
A1  - Prati, Daniel
A1  - Gossner, Martin M.
A1  - Tscharntke, Teja
A1  - Blüthgen, Nico
A1  - Bellach, Michaela
A1  - Birkhofer, Klaus
A1  - Boch, Steffen
A1  - Böhm, Stefan
A1  - Börschig, Carmen
A1  - Chatzinotas, Antonis
A1  - Christ, Sabina
A1  - Daniel, Rolf
A1  - Diekötter, Tim
A1  - Fischer, Christiane
A1  - Friedl, Thomas
A1  - Glaser, Karin
A1  - Hallmann, Christine
A1  - Hodac, Ladislav
A1  - Hölzel, Norbert
A1  - Jung, Kirsten
A1  - Klein, Alexandra-Maria
A1  - Klaus, Valentin H.
A1  - Kleinebecker, Till
A1  - Krauss, Jochen
A1  - Lange, Markus
A1  - Morris, E. Kathryn
A1  - Müller, Jörg
A1  - Nacke, Heiko
A1  - Pasalic, Esther
A1  - Rillig, Matthias C.
A1  - Rothenwoehrer, Christoph
A1  - Schally, Peter
A1  - Scherber, Christoph
A1  - Schulze, Waltraud X.
A1  - Socher, Stephanie A.
A1  - Steckel, Juliane
A1  - Steffan-Dewenter, Ingolf
A1  - Türke, Manfred
A1  - Weiner, Christiane N.
A1  - Werner, Michael
A1  - Westphal, Catrin
A1  - Wolters, Volkmar
A1  - Wubet, Tesfaye
A1  - Gockel, Sonja
A1  - Gorke, Martin
A1  - Hemp, Andreas
A1  - Renner, Swen C.
A1  - Schöning, Ingo
A1  - Pfeiffer, Simone
A1  - König-Ries, Birgitta
A1  - Buscot, Francois
A1  - Linsenmair, Karl Eduard
A1  - Schulze, Ernst-Detlef
A1  - Weisser, Wolfgang W.
A1  - Fischer, Markus
T1  - Interannual variation in land-use intensity enhances grassland multidiversity
JF  - Proceedings of the National Academy of Sciences of the United States of America
N2  - Although temporal heterogeneity is a well-accepted driver of biodiversity, effects of interannual variation in land-use intensity (LUI) have not been addressed yet. Additionally, responses to land use can differ greatly among different organisms; therefore, overall effects of land-use on total local biodiversity are hardly known. To test for effects of LUI (quantified as the combined intensity of fertilization, grazing, and mowing) and interannual variation in LUI (SD in LUI across time), we introduce a unique measure of whole-ecosystem biodiversity, multidiversity. This synthesizes individual diversity measures across up to 49 taxonomic groups of plants, animals, fungi, and bacteria from 150 grasslands. Multidiversity declined with increasing LUI among grasslands, particularly for rarer species and aboveground organisms, whereas common species and belowground groups were less sensitive. However, a high level of interannual variation in LUI increased overall multidiversity at low LUI and was even more beneficial for rarer species because it slowed the rate at which the multidiversity of rare species declined with increasing LUI. In more intensively managed grasslands, the diversity of rarer species was, on average, 18% of the maximum diversity across all grasslands when LUI was static over time but increased to 31% of the maximum when LUI changed maximally over time. In addition to decreasing overall LUI, we suggest varying LUI across years as a complementary strategy to promote biodiversity conservation.
KW  - biodiversity loss
KW  - agricultural grasslands
KW  - Biodiversity Exploratories
Y1  - 2014
U6  - https://doi.org/10.1073/pnas.1312213111
SN  - 0027-8424
VL  - 111
IS  - 1
SP  - 308
EP  - 313
PB  - National Acad. of Sciences
CY  - Washington
ER  -