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Evers, L.G. (author)Sound becomes inaudible if it consists of frequencies lower than 20 Hz, i.e. the human hearing threshold, and is called infrasound. Low frequency acoustic signals were first discovered after the eruption of the Krakatoa (Indonesia) in 1883. Due to its low frequency content, this infrasound traveled up to seven times around the globe while...doctoral thesis 2008
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Assink, J.D. (author), Waxler, R. (author), Smets, P.S.M. (author), Evers, L.G. (author)In January 2011, the state of the polar vortex in the midlatitudes changed significantly due to a minor sudden stratospheric warming event. As a result, a bidirectional duct for infrasound propagation developed in the middle atmosphere that persisted for 2 weeks. The ducts were due to two zonal wind jets, one between 30 and 50 km and the other...journal article 2014
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Evers, L.G. (author), Green, D.N. (author), Young, N.W. (author), Snellen, M. (author)Hydroacoustic signals generated by drifting icebergs that crack, disintegrate, and collide were identified on two hydrophone arrays in the Indian Ocean. These hydrophone arrays are deployed in the Sound Fixing and Ranging channel, enabling the detection of small sources over ranges of several thousand kilometers due to the low attenuation....journal article 2013
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- Brown, P.G. (author), Assink, J.D. (author), Astiz, L. (author), Blaauw, R. (author), Boslough, M.B. (author), Borovicka, J. (author), Brachet, N. (author), Brown, D. (author), Campbell-Brown, M. (author), Ceranna, L. (author), Cooke, W. (author), de Groot-Hedin, C. (author), Drob, D.P. (author), Edwards, W. (author), Evers, L.G. (author), Garces, M. (author), Gill, J. (author), Hedlin, M. (author), Kingery, A. (author), Laske, G. (author), le Pichon, A. (author), Mialle, P. (author), Moser, D.E. (author), Saffer, A. (author), Silber, E. (author), Smets, P.S.M. (author), Spalding, R.E. (author), Spurny, P. (author), Tagliaferri, E. (author), Uren, D. (author), Weryk, J. (author), Whitaker, R. (author), Krzeminski, Z. (author) journal article 2013
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Le Pichon, A. (author), Assink, J.D. (author), Heinrich, P. (author), Blanc, E. (author), Charlton-Perez, A. (author), Lee, C.F. (author), Keckhut, P. (author), Hauchecorne, A. (author), Rufenacht, R. (author), Kampfer, N. (author), Drob, D.P. (author), Smets, P.S.M. (author), Evers, L.G. (author), Ceranna, L. (author), Pilger, C. (author), Ross, O. (author), Claud, C. (author)High-resolution, ground-based and independent observations including co-located wind radiometer, lidar stations, and infrasound instruments are used to evaluate the accuracy of general circulation models and data-constrained assimilation systems in the middle atmosphere at northern hemisphere midlatitudes. Systematic comparisons between...journal article 2015
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Evers, L.G. (author), Van Geyt, A.R.J. (author), Smets, P. (author), Fricke, J.T. (author)Long-range infrasound propagation strongly depends on the state of the stratosphere. Infrasound can be efficiently ducted between the Earth's surface and the stratopause under a favorable wind and temperature structure between 40 and 50 km altitude. Understanding infrasound propagation under variable stratospheric conditions is of importance for...journal article 2012
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Smets, P.S.M. (author), Evers, L.G. (author)A method is presented to study the life cycle of a SSW using infrasonic ambient noise observations. The potential of infrasound is shown to provide the missing observations required by numerical weather prediction to better resolve the upper atmosphere. The 2009 major SSW is reanalyzed using the Evers and Siegmund (2009) data set. Microbarom...journal article 2014
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Smets, P.S.M. (author), Evers, L.G. (author), Näsholm, S.P. (author), Gibbons, S.J. (author)This study demonstrates probabilistic infrasound propagation modeling using realistic perturbations. The ensembles of perturbed analyses, provided by the European Centre for Medium-Range Weather Forecasts (ECMWF), include error variances of both model and assimilated observations. Ensemble spread profiles indicate a yearly mean effective sound...journal article 2015
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Fricke, J.T. (author), El Allouche, N. (author), Simons, D.G. (author), Ruigrok, E.N. (author), Wapenaar, C.P.A. (author), Evers, L.G. (author)The atmospheric wind and temperature can be estimated through the traveltimes of infrasound between pairs of receivers. The traveltimes can be obtained by infrasonic interferometry. In this study, the theory of infrasonic interferometry is verified and applied to modeled stratospherically refracted waves. Synthetic barograms are generated using...journal article 2013
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Fricke, J.T. (author), Evers, L.G. (author), Smets, P.S.M. (author), Wapenaar, C.P.A. (author), Simons, D.G. (author)We present the results of infrasonic interferometry applied to microbaroms, obtained from ambient noise. For this purpose the “Large Aperture Infrasound Array” (LAIA) was used, which has been installed in the Netherlands. Preprocessing appeared to be an essential step in enhancing the microbarom signals from ambient noise that strongly...journal article 2014
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- Smets, P. (author), Evers, L.G. (author), Wapenaar, C.P.A. (author) journal article 2014
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Evers, L.G. (author), Siegmund, P. (author)The study of infrasound is experiencing a renaissance since it was chosen as a verification technique for the Comprehensive Nuclear-Test-Ban Treaty. The success of the verification technique strongly depends on knowledge of upper atmospheric processes. The ability of infrasound to probe the upper atmosphere starts to be exploited, taking the...journal article 2009
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Evers, L.G. (author), Brown, D. (author), Heaney, K.D. (author), Assink, J.D. (author), Smets, P.S.M. (author), Snellen, M. (author)Atmospheric low-frequency sound, i.e., infrasound, from underwater events has not been considered thus far, due to the high impedance contrast of the water-air interface making it almost fully reflective. Here we report for the first time on atmospheric infrasound from a large underwater earthquake (Mw 8.1) near the Macquarie Ridge, which was...journal article 2014
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Popova, O.P. (author), Jenniskens, P. (author), Emel'yanenko, V. (author), Kartashova, A. (author), Biryukov, E. (author), Khaibrakhmanov, S. (author), Shuvalov, V. (author), Rybnov, Y. (author), Dudorov, A. (author), Grokhovsky, V.I. (author), Badyukov, D.D. (author), Yin, Q.Z (author), Gural, P.S. (author), Albers, J. (author), Granvik, M. (author), Evers, L.G. (author)The asteroid impact near the Russian city of Chelyabinsk on 15 February 2013 was the largest airburst on Earth since the 1908 Tunguska event, causing a natural disaster in an area with a population exceeding one million. Because it occurred in an era with modern consumer electronics, field sensors, and laboratory techniques, unprecedented...journal article 2013
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Averbuch, G. (author), Assink, Jelle D. (author), Smets, P.S.M. (author), Evers, L.G. (author)Low-frequency acoustic, i.e., infrasound, waves are measured by sparse arrays of microbarometers. Recorded data are processed by automatic detection algorithms based on array-processing techniques such as time-domain beam forming and f-k analysis. These algorithms use a signal-to-noise ratio (S/N) value as a detection criterion. In the case...journal article 2018
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Patrick, Samantha C. (author), Assink, Jelle D. (author), Basille, Mathieu (author), Clusella-Trullas, Susana (author), Clay, Thomas A. (author), den Ouden, O.F.C. (author), Joo, Rocío (author), Evers, L.G. (author), Smets, P.S.M. (author)Seabirds are amongst the most mobile of all animal species and spend large amounts of their lives at sea. They cross vast areas of ocean that appear superficially featureless, and our understanding of the mechanisms that they use for navigation remains incomplete, especially in terms of available cues. In particular, several large-scale...journal article 2021
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den Ouden, O.F.C. (author), Smets, P.S.M. (author), Assink, Jelle D. (author), Evers, L.G. (author)A method is introduced to reconstruct microbarom soundscapes in absolute values. The soundscapes are compared to remote infrasound recordings from infrasound array I23FR (Kerguelen Island) and in situ recordings by the INFRA-EAR, a biologger deployed near the Crozet Islands. The reconstruction method accounts for all-acoustic contributions,...journal article 2021
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Smets, P.S.M. (author), Weemstra, C. (author), Evers, L.G. (author)We report on the extraction of deep ocean travel time variations from time-lapse cross-correlations between a hydrophone station and a three-component broadband seismometer. The signals we cross-correlate in this study result from repeated activity by the Monowai seamount, one of the most active submarine volcanoes of the Tonga-Kermadec ridge...journal article 2022
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Shani-Kadmiel, Shahar (author), Averbuch, G. (author), Smets, P.S.M. (author), Assink, Jelle (author), Evers, L.G. (author)In the days following the January 12, 2010 M<sub>w</sub> 7 Haiti earthquake the shaking intensity near the epicenter was overestimated and the spatial extent of the potentially damaging shaking was underestimated. This was due to the lack of seismometers in the near-source region at the time of the earthquake. Besides seismic waves,...journal article 2021
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den Ouden, O.F.C. (author), Assink, Jelle D. (author), Oudshoorn, Cornelis D. (author), Filippi, Dominique (author), Evers, L.G. (author)Geophysical studies and real-time monitoring of natural hazards, such as volcanic eruptions or severe weather events, benefit from the joint analysis of multiple geophysical parameters. However, typical geophysical measurement platforms still provide logging solutions for a single parameter, due to different community standards and the higher...journal article 2021
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