Three large‐scale infrasound calibration experiments were conducted in 2009 and 2011 to test the International Monitoring System (IMS) infrasound network and provide ground truth data for infrasound propagation studies. Here we provide an overview of the deployment, detonation, atmospheric specifications, infrasound array observations, and propagation modeling for the experiments. The experiments at the Sayarim Military Range, Israel, had equivalent TNT yields of 96.0, 7.4, and 76.8 t of explosives on 26 August 2009, 24 January 2011, and 26 January 2011, respectively. Successful international collaboration resulted in the deployment of numerous portable infrasound arrays in the region to supplement the IMS network and increase station density. Infrasound from the detonations is detected out to ~3500 km to the northwest in 2009 and ~6300 km to the northeast in 2011, reflecting the highly anisotropic nature of long‐range infrasound propagation. For 2009, the moderately strong stratospheric wind jet results in a well‐predicted set of arrivals at numerous arrays to the west‐northwest. A second set of arrivals is also apparent, with low celerities and high frequencies. These arrivals are not predicted by the propagation modeling and result from unresolved atmospheric features. Strong eastward tropospheric winds (up to ~70 m/s) in 2011 produce high‐amplitude tropospheric arrivals recorded out to >1000 km to the east. Significant eastward stratospheric winds (up to ~80 m/s) in 2011 generate numerous stratospheric arrivals and permit the long‐range detection (i.e., >1000 km). No detections are made in directions opposite the tropospheric and stratospheric wind jets for any of the explosions. Comparison of predicted transmission loss and observed infrasound arrivals gives qualitative agreement. Propagation modeling for the 2011 experiments predicts lower transmission loss in the direction of the downwind propagation compared to the 2009 experiment, consistent with the greater detection distance. Observations also suggest a more northerly component to the stratospheric winds for the 2009 experiment and less upper atmosphere attenuation. The Sayarim infrasound calibration experiments clearly demonstrate the complexity and variability of the atmosphere, and underscore the utility of large‐scale calibration experiments with dense networks for better understanding infrasound propagation and detection. Additionally, they provide a rich data set for future scientific research.
Displaying three-dimensional content on a flat display is bound to reduce the impression of depth, particularly for mobile video see-trough augmented reality. Several applications in this domain can benefit from accurate depth perception, especially if there are contradictory depth cues, like occlusion in a x-ray visualization. The use of stereoscopy for this effect is already prevalent in headmounted displays, but there is little research on the applicability for hand-held augmented reality. We have implemented such a prototype using an off-the-shelf smartphone equipped with a stereo camera and an autostereoscopic display. We designed and conducted an extensive user study to explore the effects of stereoscopic hand-held augmented reality on depth perception. The results show that in this scenario depth judgment is mostly influenced by monoscopic depth cues, but our system can improve positioning accuracy in challenging scenes.
Approved for public release; distribution unlimited. ii REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing the burden, to Department of Defense, Washington Headquarters Services, Directorate for Information Operations and Reports (0704-0188), 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302. Respondents should be aware that notwithstanding any other provision of law, no person shall be subject to any penalty for failing to comply with a collection of information if it does not display a currently valid OMB control number.
There are numerous reports in the literature on the observation of infrasound emitted from tornadic thunderstorms. Most of these observations have been made from sensors that are several hundreds of kilometers from the location of the storm, and “ground truth” about the tornadic activity is not well established. We report here on a campaign carried out during the summer of 2011 in which 50 infrasound microphones were deployed, as part of an ongoing multi-university program on hazard detection and alert funded by the National Oceanic and Atmospheric Administration. Sensors were placed along the paths of developing tornadic storms. We focus here on a severe weather outbreak that took place near Oklahoma City on May 24, 2011, in which a total of 7 tornados including one F5 and two F2 tornados were produced. Three sensors were located between the paths of an F4 and an F5 tornado, and 11 additional sensors were located northeast of an F4 tornado that generated a 75-km track. Substantial meteorological information, including ground truth about tornados (intensity and size as a function of time), and the relative close proximity of the sensors to the storms, provides us with a level of detail not available in previous storms. We will report on our infrasound measurements and analysis from this outbreak as well as discuss data from two other interceptions of tornadic storms, which occurred on May 30 and June 19, 2011.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.