Institution
University of Potsdam
Education•Potsdam, Germany•
About: University of Potsdam is a education organization based out in Potsdam, Germany. It is known for research contribution in the topics: Population & Computer science. The organization has 9629 authors who have published 26740 publications receiving 759745 citations. The organization is also known as: Universität Potsdam.
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TL;DR: The authors show that Anak Krakatau exhibited an elevated state of activity several months prior to the collapse, including precursory thermal anomalies, an increase in the island’s surface area, and a gradual seaward motion of the southwestern flank.
Abstract: Flank instability and sector collapses, which pose major threats, are common on volcanic islands. On 22 Dec 2018, a sector collapse event occurred at Anak Krakatau volcano in the Sunda Strait, triggering a deadly tsunami. Here we use multiparametric ground-based and space-borne data to show that prior to its collapse, the volcano exhibited an elevated state of activity, including precursory thermal anomalies, an increase in the island’s surface area, and a gradual seaward motion of its southwestern flank on a dipping decollement. Two minutes after a small earthquake, seismic signals characterize the collapse of the volcano’s flank at 13:55 UTC. This sector collapse decapitated the cone-shaped edifice and triggered a tsunami that caused 430 fatalities. We discuss the nature of the precursor processes underpinning the collapse that culminated in a complex hazard cascade with important implications for the early detection of potential flank instability at other volcanoes. On 22 December 2018, the western flank of Anak Krakatau collapsed into the sea of the Sunda Strait triggering a tsunami which killed approximately 430 people and displaced 33,000. Here, the authors show that Anak Krakatau exhibited an elevated state of activity several months prior to the collapse, including precursory thermal anomalies, an increase in the island’s surface area, and a gradual seaward motion of the southwestern flank.
246 citations
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TL;DR: Analysis of the atmospheric conditions that lead to these teleconnections confirms Rossby waves as the physical mechanism underlying these global teleconnection patterns and emphasizes their crucial role in dynamical tropical–extratropical couplings.
Abstract: Climatic observables are often correlated across long spatial distances, and extreme events, such as heatwaves or floods, are typically assumed to be related to such teleconnections1,2. Revealing atmospheric teleconnection patterns and understanding their underlying mechanisms is of great importance for weather forecasting in general and extreme-event prediction in particular3,4, especially considering that the characteristics of extreme events have been suggested to change under ongoing anthropogenic climate change5–8. Here we reveal the global coupling pattern of extreme-rainfall events by applying complex-network methodology to high-resolution satellite data and introducing a technique that corrects for multiple-comparison bias in functional networks. We find that the distance distribution of significant connections (P < 0.005) around the globe decays according to a power law up to distances of about 2,500 kilometres. For longer distances, the probability of significant connections is much higher than expected from the scaling of the power law. We attribute the shorter, power-law-distributed connections to regional weather systems. The longer, super-power-law-distributed connections form a global rainfall teleconnection pattern that is probably controlled by upper-level Rossby waves. We show that extreme-rainfall events in the monsoon systems of south-central Asia, east Asia and Africa are significantly synchronized. Moreover, we uncover concise links between south-central Asia and the European and North American extratropics, as well as the Southern Hemisphere extratropics. Analysis of the atmospheric conditions that lead to these teleconnections confirms Rossby waves as the physical mechanism underlying these global teleconnection patterns and emphasizes their crucial role in dynamical tropical–extratropical couplings. Our results provide insights into the function of Rossby waves in creating stable, global-scale dependencies of extreme-rainfall events, and into the potential predictability of associated natural hazards. Complex networks are used to analyse global-scale teleconnections between extreme-rainfall events, revealing a peak in the distance distribution of statistically significant connections at around 10,000 kilometres.
246 citations
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TL;DR: In this paper, the life time and loss rate for a trapped atom coupled to fluctuating fields in the vicinity of a room-temperature metallic and/or dielectric surface were derived.
Abstract: We derive the life time and loss rate for a trapped atom that is coupled to fluctuating fields in the vicinity of a room-temperature metallic and/or dielectric surface. Our results indicate a clear predominance of near-field effects over ordinary blackbody radiation. We develop a theoretical framework for both charged ions and neutral atoms with and without spin. Loss processes that are due to a transition to an untrapped internal state are included.
246 citations
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American Museum of Natural History1, University of Tartu2, University of Gothenburg3, Swedish University of Agricultural Sciences4, University of Oslo5, University of Hawaii at Manoa6, University of Copenhagen7, Purdue University8, Academy of Sciences of the Czech Republic9, University of Turin10, Harvard University11, Synlab Group12, Universidad Santo Tomás13, Universidad Mayor14, University of Electronic Science and Technology of China15, University of Warsaw16, Swedish Museum of Natural History17, Mae Fah Luang University18, University of Florida19, Laos Ministry of Agriculture and Forestry20, São Paulo Federal Institute of Education, Science and Technology21, Estonian University of Life Sciences22, Federal University of Pernambuco23, United States Department of Energy24, Del Rosario University25, National Autonomous University of Mexico26, Ghent University27, West Bengal State University28, Beijing Forestry University29, Pontifical Catholic University of Chile30, Chinese Academy of Sciences31, Field Museum of Natural History32, University of Potsdam33, Leibniz Association34, University of Gilan35, University of Alaska Fairbanks36, University of Tokyo37, University of Costa Rica38, Forest Research Institute39, Westmead Hospital40, University of Sydney41, Uppsala University42, Landcare Research43, University of Chittagong44, University of Memphis45, United Arab Emirates University46, Ministry of Land and Resources of the People's Republic of China47, University of Pretoria48, Royal Botanic Gardens49, Ocean University of China50, Guizhou University51, Mie University52, Hokkaido University53
TL;DR: Fungal traits and character database FungalTraits operating at genus and species hypothesis levels is presented in this article, which includes 17 lifestyle related traits of fungal and Stramenopila genera.
Abstract: The cryptic lifestyle of most fungi necessitates molecular identification of the guild in environmental studies. Over the past decades, rapid development and affordability of molecular tools have tremendously improved insights of the fungal diversity in all ecosystems and habitats. Yet, in spite of the progress of molecular methods, knowledge about functional properties of the fungal taxa is vague and interpretation of environmental studies in an ecologically meaningful manner remains challenging. In order to facilitate functional assignments and ecological interpretation of environmental studies we introduce a user friendly traits and character database FungalTraits operating at genus and species hypothesis levels. Combining the information from previous efforts such as FUNGuild and Fun(Fun) together with involvement of expert knowledge, we reannotated 10,210 and 151 fungal and Stramenopila genera, respectively. This resulted in a stand-alone spreadsheet dataset covering 17 lifestyle related traits of fungal and Stramenopila genera, designed for rapid functional assignments of environmental studies. In order to assign the trait states to fungal species hypotheses, the scientific community of experts manually categorised and assigned available trait information to 697,413 fungal ITS sequences. On the basis of those sequences we were able to summarise trait and host information into 92,623 fungal species hypotheses at 1% dissimilarity threshold.
245 citations
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TL;DR: In this paper, an evolving bipolar active region that exhibits flux cancellation at the internal polarity inversion line, the formation of a soft X-ray sigmoid along the inversion lines and a coronal mass ejection was studied.
Abstract: Aims. We study an evolving bipolar active region that exhibits flux cancellation at the internal polarity inversion line, the formation of a soft X-ray sigmoid along the inversion line and a coronal mass ejection. The aim is to investigate the quantity of flux cancellation that is involved in flux rope formation in the time period leading up to the eruption.Methods. The active region is studied using its extreme ultraviolet and soft X-ray emissions as it evolves from a sheared arcade to flux rope configuration. The evolution of the photospheric magnetic field is described and used to estimate how much flux is reconnected into the flux rope.Results. About one third of the active region flux cancels at the internal polarity inversion line in the 2.5 days leading up to the eruption. In this period, the coronal structure evolves from a weakly to a highly sheared arcade and then to a sigmoid that crosses the inversion line in the inverse direction. These properties suggest that a flux rope has formed prior to the eruption. The amount of cancellation implies that up to 60% of the active region flux could be in the body of the flux rope. We point out that only part of the cancellation contributes to the flux in the rope if the arcade is only weakly sheared, as in the first part of the evolution. This reduces the estimated flux in the rope to similar to 30% or less of the active region flux. We suggest that the remaining discrepancy between our estimate and the limiting value of similar to 10% of the active region flux, obtained previously by the flux rope insertion method, results from the incomplete coherence of the flux rope, due to nonuniform cancellation along the polarity inversion line. A hot linear feature is observed in the active region which rises as part of the eruption and then likely traces out the field lines close to the axis of the flux rope. The flux cancellation and changing magnetic connections at one end of this feature suggest that the flux rope reaches coherence by reconnection immediately before and early in the impulsive phase of the associated flare. The sigmoid is destroyed in the eruption but reforms quickly, with the amount of cancellation involved being much smaller than in the course of its original formation.
245 citations
Authors
Showing all 9969 results
Name | H-index | Papers | Citations |
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Cyrus Cooper | 204 | 1869 | 206782 |
Markus Antonietti | 176 | 1068 | 127235 |
Marc Weber | 167 | 2716 | 153502 |
Peter Capak | 147 | 679 | 70483 |
Heiner Boeing | 140 | 1024 | 92580 |
Alisdair R. Fernie | 133 | 1010 | 64026 |
Klaus-Robert Müller | 129 | 764 | 79391 |
Claudia Felser | 113 | 1198 | 58589 |
Guochun Zhao | 113 | 406 | 40886 |
Matthias Steinmetz | 112 | 461 | 67802 |
Jürgen Kurths | 105 | 1038 | 62179 |
Peter Schmidt | 105 | 638 | 61822 |
Erwin P. Bottinger | 102 | 342 | 42089 |
Knud Jahnke | 94 | 352 | 31542 |
Gerd Gigerenzer | 94 | 533 | 52356 |