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Sample records for agile meteor radar

  1. The Southern Argentine Agile Meteor Radar (SAAMER)

    NASA Astrophysics Data System (ADS)

    Janches, Diego

    2014-11-01

    The Southern Argentina Agile Meteor Radar (SAAMER) is a new generation system deployed in Rio Grande, Tierra del Fuego, Argentina (53 S) in May 2008. SAAMER transmits 10 times more power than regular meteor radars, and uses a newly developed transmitting array, which focuses power upward instead of the traditional single-antenna-all-sky configuration. The system is configured such that the transmitter array can also be utilized as a receiver. The new design greatly increases the sensitivity of the radar enabling the detection of large number of particles at low zenith angles. The more concentrated transmitted power enables additional meteor studies besides those typical of these systems based on the detection of specular reflections, such as routine detections of head echoes and non-specular trails, previously only possible with High Power and Large Aperture radars. In August 2010, SAAMER was upgraded to a system capable to determine meteoroid orbital parameters. This was achieved by adding two remote receiving stations approximately 10 km away from the main site in near perpendicular directions. The upgrade significantly expands the science that is achieved with this new radar enabling us to study the orbital properties of the interplanetary dust environment. Because of the unique geographical location, SAAMER allows for additional inter-hemispheric comparison with measurements from Canadian Meteor Orbit Radar, which is geographically conjugate. Initial surveys show, for example, that SAAMER observes a very strong contribution of the South Toroidal Sporadic meteor source, of which limited observational data is available. In addition, SAAMER offers similar unique capabilities for meteor showers and streams studies given the range of ecliptic latitudes that the system enables detailed study of showers at high southern latitudes (e.g July Phoenicids or Puppids complex). Finally, SAAMER is ideal for the deployment of complementary instrumentation in both, permanent

  2. The Southern Argentina Agile Meteor Radar (SAAMER): Platform for comprehensive meteor radar observations and studies

    NASA Astrophysics Data System (ADS)

    Janches, D.; Hormaechea, J.; Pifko, S.; Hocking, W.; Fritts, D.; Brunini, C.; Close, S.; Michell, R.; Samara, M.

    2014-07-01

    The Southern Argentina Agile Meteor Radar (SAAMER) is a new generation system deployed in Rio Grande, Tierra del Fuego, Argentina (53^oS) in May 2008 (Janches et al., 2013,2014). SAAMER transmits 10 times more power than regular meteor radars, and uses a newly developed transmitting array, which focuses power upward instead of the traditional single-antenna-all-sky configuration. The system is configured such that the transmitter array can also be utilized as a receiver. The new design greatly increases the sensitivity of the radar enabling the detection of large numbers of particles at low zenith angles. The more concentrated transmitted power enables additional meteor studies besides those typical of these systems based on the detection of specular reflections, such as routine detections of head echoes and non-specular trails, previously only possible with High Power and Large Aperture radars (Janches et al., 2014). In August 2010, SAAMER was upgraded to a system capable to determine meteoroid orbital parameters. This was achieved by adding two remote receiving stations approximately 10 km away from the main site in near perpendicular directions (Pifko et al., 2014). The upgrade significantly expands the science that is achieved with this new radar enabling us to study the orbital properties of the interplanetary dust environment. Because of the unique geographical location, the SAAMER allows for additional inter-hemispheric comparison with measurements from Canadian Meteor Orbit Radar, which is geographically conjugate. Initial surveys show, for example, that SAAMER observes a very strong contribution of the South Toroidal Sporadic meteor source (Pifko et al., 2014), of which limited observational data is available. In addition, SAAMER offers similar unique capabilities for meteor showers and streams studies given the range of ecliptic latitudes that the system enables to survey (Janches et al., 2013). It can effectively observe radiants from the ecliptic south

  3. Interferometric Meteor Head Echo Observations using the Southern Argentina Agile Meteor Radar (SAAMER)

    NASA Technical Reports Server (NTRS)

    Janches, D.; Hocking, W.; Pifko, S.; Hormaechea, J. L.; Fritts, D. C.; Brunini, C; Michell, R.; Samara, M.

    2013-01-01

    A radar meteor echo is the radar scattering signature from the free-electrons in a plasma trail generated by entry of extraterrestrial particles into the atmosphere. Three categories of scattering mechanisms exist: specular, nonspecular trails, and head-echoes. Generally, there are two types of radars utilized to detect meteors. Traditional VHF meteor radars (often called all-sky1radars) primarily detect the specular reflection of meteor trails traveling perpendicular to the line of sight of the scattering trail, while High Power and Large Aperture (HPLA) radars efficiently detect meteor head-echoes and, in some cases, non-specular trails. The fact that head-echo measurements can be performed only with HPLA radars limits these studies in several ways. HPLA radars are very sensitive instruments constraining the studies to the lower masses, and these observations cannot be performed continuously because they take place at national observatories with limited allocated observing time. These drawbacks can be addressed by developing head echo observing techniques with modified all-sky meteor radars. In addition, the fact that the simultaneous detection of all different scattering mechanisms can be made with the same instrument, rather than requiring assorted different classes of radars, can help clarify observed differences between the different methodologies. In this study, we demonstrate that such concurrent observations are now possible, enabled by the enhanced design of the Southern Argentina Agile Meteor Radar (SAAMER) deployed at the Estacion Astronomica Rio Grande (EARG) in Tierra del Fuego, Argentina. The results presented here are derived from observations performed over a period of 12 days in August 2011, and include meteoroid dynamical parameter distributions, radiants and estimated masses. Overall, the SAAMER's head echo detections appear to be produced by larger particles than those which have been studied thus far using this technique.

  4. Interferometric meteor head echo observations using the Southern Argentina Agile Meteor Radar

    NASA Astrophysics Data System (ADS)

    Janches, D.; Hocking, W.; Pifko, S.; Hormaechea, J. L.; Fritts, D. C.; Brunini, C.; Michell, R.; Samara, M.

    2014-03-01

    A radar meteor echo is the radar scattering signature from the free electrons generated by the entry of extraterrestrial particles into the atmosphere. Three categories of scattering mechanisms exist: specular, nonspecular trails, and head echoes. Generally, there are two types of radars utilized to detect meteors. Traditional VHF all-sky meteor radars primarily detect the specular trails, while high-power, large-aperture (HPLA) radars efficiently detect meteor head echoes and, in some cases, nonspecular trails. The fact that head echo measurements can be performed only with HPLA radars limits these studies in several ways. HPLA radars are sensitive instruments constraining the studies to the lower masses, and these observations cannot be performed continuously because they take place at national observatories with limited allocated observing time. These drawbacks can be addressed by developing head echo observing techniques with modified all-sky meteor radars. Such systems would also permit simultaneous detection of all different scattering mechanisms using the same instrument, rather than requiring assorted different classes of radars, which can help clarify observed differences between the different methodologies. In this study, we demonstrate that such concurrent observations are now possible, enabled by the enhanced design of the Southern Argentina Agile Meteor Radar (SAAMER). The results presented here are derived from observations performed over a period of 12 days in August 2011 and include meteoroid dynamical parameter distributions, radiants, and estimated masses. Overall, the SAAMER's head echo detections appear to be produced by larger particles than those which have been studied thus far using this technique.

  5. Southern Argentina Agile Meteor Radar: Initial assessment of gravity wave momentum fluxes

    NASA Astrophysics Data System (ADS)

    Fritts, D. C.; Janches, D.; Hocking, W. K.

    2010-10-01

    The Southern Argentina Agile Meteor Radar (SAAMER) was installed on Tierra del Fuego (53.8°S) in May 2008 and has been operational since that time. This paper describes tests of the SAAMER ability to measure gravity wave momentum fluxes and applications of this capability during different seasons. Test results for specified mean, tidal, and gravity wavefields, including tidal amplitudes and gravity wave momentum fluxes varying strongly with altitude and/or time, suggest that the distribution of meteors throughout the diurnal cycle and averaged over a month allows characterization of both monthly mean profiles and diurnal variations of the gravity wave momentum fluxes. Applications of the same methods for real data suggest confidence in the monthly mean profiles and the composite day diurnal variations of gravity wave momentum fluxes at altitudes where meteor counts are sufficient to yield good statistical fits to the data. Monthly mean zonal winds and gravity wave momentum fluxes exhibit anticorrelations consistent with those seen at other midlatitude and high-latitude radars during austral spring and summer, when no strong local gravity wave sources are apparent. When stratospheric variances are significantly enhanced over the Drake Passage “hot spot” during austral winter, however, MLT winds and momentum fluxes over SAAMER exhibit very different correlations that suggest that MLT dynamics are strongly influenced by strong local gravity wave sources within this “hot spot.” SAAMER measurements of mean zonal and meridional winds at these times and their differences from measurements at a conjugate site provide further support for the unusual momentum flux measurements.

  6. An initial meteoroid stream survey in the southern hemisphere using the Southern Argentina Agile Meteor Radar (SAAMER)

    NASA Astrophysics Data System (ADS)

    Janches, D.; Hormaechea, J. L.; Brunini, C.; Hocking, W.; Fritts, D. C.

    2013-04-01

    We present in this manuscript a 4 year survey of meteor shower radiants utilizing the Southern Argentina Agile Meteor Radar (SAAMER). SAAMER, which operates at the southern most region of South America, is a new generation SKiYMET system designed with significant differences from typical meteor radars including high transmitted power and an 8-antenna transmitting array enabling large detected rates at low zenith angles. We applied the statistical methodology developed by Jones and Jones (Jones, J., Jones, W. [2006]. Month. Not. R. Astron. Soc. 367, 1050-1056) to the data collected each day and compiled the results into 1 composite representative year at 1° resolution in Solar Longitude. We then search for enhancements in the activity which last for at least 3 days and evolve temporally as is expected from a meteor shower. Using this methodology, we have identified in our data 32 shower radiants, two of which were not part of the IAU commission 22 meteor shower working list. Recently, SAAMER's capabilities were enhanced by adding two remote stations to receive meteor forward scatter signals from meteor trails and thus enable the determination of meteoroid orbital parameters. SAAMER started recording orbits in January 2012 and future surveys will focus on the search for unknown meteor streams, in particular in the southern ecliptic sky.

  7. An Initial Meteoroid Stream Survey in the Southern Hemisphere Using the Southern Argentina Agile Meteor Radar (SAAMER)

    NASA Technical Reports Server (NTRS)

    Janches, D.; Hormaechea, J. L.; Brunini, C.; Hocking, W.; Fritts, D. C.

    2013-01-01

    We present in this manuscript a 4 year survey of meteor shower radiants utilizing the Southern Argentina Agile Meteor Radar (SAAMER). SAAMER, which operates at the southern most region of South America, is a new generation SKiYMET system designed with significant differences from typical meteor radars including high transmitted power and an 8-antenna transmitting array enabling large detected rates at low zenith angles. We applied the statistical methodology developed by Jones and Jones (Jones, J., Jones, W. [2006]. Month. Not. R. Astron. Soc. 367, 1050-1056) to the data collected each day and compiled the results into 1 composite representative year at 1 resolution in Solar Longitude. We then search for enhancements in the activity which last for at least 3 days and evolve temporally as is expected from a meteor shower. Using this methodology, we have identified in our data 32 shower radiants, two of which were not part of the IAU commission 22 meteor shower working list. Recently, SAAMER's capabilities were enhanced by adding two remote stations to receive meteor forward scatter signals from meteor trails and thus enable the determination of meteoroid orbital parameters. SAAMER started recording orbits in January 2012 and future surveys will focus on the search for unknown meteor streams, in particular in the southern ecliptic sky.

  8. Drake Antarctic Agile Meteor Radar first results: Configuration and comparison of mean and tidal wind and gravity wave momentum flux measurements with Southern Argentina Agile Meteor Radar

    NASA Astrophysics Data System (ADS)

    Fritts, D. C.; Janches, D.; Iimura, H.; Hocking, W. K.; Bageston, J. V.; Leme, N. M. P.

    2012-01-01

    A new generation meteor radar was installed at the Brazilian Antarctic Comandante Ferraz Base (62.1°S) in March 2010. This paper describes the motivations for the radar location, its measurement capabilities, and comparisons of measured mean winds, tides, and gravity wave momentum fluxes from April to June of 2010 and 2011 with those by a similar radar on Tierra del Fuego (53.8°S). Motivations for the radars include the “hotspot” of small-scale gravity wave activity extending from the troposphere into the mesosphere and lower thermosphere (MLT) centered over the Drake Passage, the maximum of the semidiurnal tide at these latitudes, and the lack of other MLT wind measurements in this latitude band. Mean winds are seen to be strongly modulated at planetary wave and longer periods and to exhibit strong coherence over the two radars at shorter time scales as well as systematic seasonal variations. The semidiurnal tide contributes most to the large-scale winds over both radars, with maximum tidal amplitudes during May and maxima at the highest altitudes varying from ˜20 to >70 ms-1. In contrast, the diurnal tide and various planetary waves achieve maximum winds of ˜10 to 20 ms-1. Monthly mean gravity wave momentum fluxes appear to reflect the occurrence of significant sources at lower altitudes, with relatively small zonal fluxes over both radars, but with significant, and opposite, meridional momentum fluxes below ˜85 km. These suggest gravity waves propagating away from the Drake Passage at both sites, and may indicate an important source region accounting in part for this “hotspot.”

  9. The Southern Argentina Agile MEteor Radar Orbital System (SAAMER-OS): An Initial Sporadic Meteoroid Orbital Survey in the Southern Sky

    NASA Astrophysics Data System (ADS)

    Janches, D.; Close, S.; Hormaechea, J. L.; Swarnalingam, N.; Murphy, A.; O'Connor, D.; Vandepeer, B.; Fuller, B.; Fritts, D. C.; Brunini, C.

    2015-08-01

    We present an initial survey in the southern sky of the sporadic meteoroid orbital environment obtained with the Southern Argentina Agile MEteor Radar (SAAMER) Orbital System (OS), in which over three-quarters of a million orbits of dust particles were determined from 2012 January through 2015 April. SAAMER-OS is located at the southernmost tip of Argentina and is currently the only operational radar with orbit determination capability providing continuous observations of the southern hemisphere. Distributions of the observed meteoroid speed, radiant, and heliocentric orbital parameters are presented, as well as those corrected by the observational biases associated with the SAAMER-OS operating parameters. The results are compared with those reported by three previous surveys performed with the Harvard Radio Meteor Project, the Advanced Meteor Orbit Radar, and the Canadian Meteor Orbit Radar, and they are in agreement with these previous studies. Weighted distributions for meteoroids above the thresholds for meteor trail electron line density, meteoroid mass, and meteoroid kinetic energy are also considered. Finally, the minimum line density and kinetic energy weighting factors are found to be very suitable for meteroid applications. The outcomes of this work show that, given SAAMER’s location, the system is ideal for providing crucial data to continuously study the South Toroidal and South Apex sporadic meteoroid apparent sources.

  10. THE SOUTHERN ARGENTINA AGILE METEOR RADAR ORBITAL SYSTEM (SAAMER-OS): AN INITIAL SPORADIC METEOROID ORBITAL SURVEY IN THE SOUTHERN SKY

    SciTech Connect

    Janches, D.; Swarnalingam, N.; Close, S.; Hormaechea, J. L.; Murphy, A.; O’Connor, D.; Vandepeer, B.; Fuller, B.; Fritts, D. C.; Brunini, C. E-mail: nimalan.swarnalingam@nasa.gov E-mail: jlhormaechea@untdf.edu.ar E-mail: doconnor@gsoft.com.au E-mail: bfuller@gsoft.com.au E-mail: claudiobrunini@yahoo.com

    2015-08-10

    We present an initial survey in the southern sky of the sporadic meteoroid orbital environment obtained with the Southern Argentina Agile MEteor Radar (SAAMER) Orbital System (OS), in which over three-quarters of a million orbits of dust particles were determined from 2012 January through 2015 April. SAAMER-OS is located at the southernmost tip of Argentina and is currently the only operational radar with orbit determination capability providing continuous observations of the southern hemisphere. Distributions of the observed meteoroid speed, radiant, and heliocentric orbital parameters are presented, as well as those corrected by the observational biases associated with the SAAMER-OS operating parameters. The results are compared with those reported by three previous surveys performed with the Harvard Radio Meteor Project, the Advanced Meteor Orbit Radar, and the Canadian Meteor Orbit Radar, and they are in agreement with these previous studies. Weighted distributions for meteoroids above the thresholds for meteor trail electron line density, meteoroid mass, and meteoroid kinetic energy are also considered. Finally, the minimum line density and kinetic energy weighting factors are found to be very suitable for meteroid applications. The outcomes of this work show that, given SAAMER’s location, the system is ideal for providing crucial data to continuously study the South Toroidal and South Apex sporadic meteoroid apparent sources.

  11. Radar Meteor Observations in Australia

    NASA Astrophysics Data System (ADS)

    Elford, W. G.

    1993-01-01

    During the last decade extensive meteor studies have been carried out in Australia using radio systems operating at frequencies between 2 and 30 MHz. Part of this program has been a deliberate effort to detect meteors above the "echo ceiling" of about 105 km associated with radars operating above 30 MHz. In fact the echo ceiling has been raised to 140 km with a dramatic increase in meteor flux [1]. The other aspect of these studies has been the use a low frequency (6-30MHz) surveillance radar to detect and record meteors over the horizon, using backscatter via ionospheric F-region. The power of the radar is such that the micrometeoroid limit is being approached [2]. The surveillance radar has confirmed the new estimates of meteor flux and extended to a mass limit of 0.2 microgram.

  12. Coded continuous wave meteor radar

    NASA Astrophysics Data System (ADS)

    Vierinen, Juha; Chau, Jorge L.; Pfeffer, Nico; Clahsen, Matthias; Stober, Gunter

    2016-03-01

    The concept of a coded continuous wave specular meteor radar (SMR) is described. The radar uses a continuously transmitted pseudorandom phase-modulated waveform, which has several advantages compared to conventional pulsed SMRs. The coding avoids range and Doppler aliasing, which are in some cases problematic with pulsed radars. Continuous transmissions maximize pulse compression gain, allowing operation at lower peak power than a pulsed system. With continuous coding, the temporal and spectral resolution are not dependent on the transmit waveform and they can be fairly flexibly changed after performing a measurement. The low signal-to-noise ratio before pulse compression, combined with independent pseudorandom transmit waveforms, allows multiple geographically separated transmitters to be used in the same frequency band simultaneously without significantly interfering with each other. Because the same frequency band can be used by multiple transmitters, the same interferometric receiver antennas can be used to receive multiple transmitters at the same time. The principles of the signal processing are discussed, in addition to discussion of several practical ways to increase computation speed, and how to optimally detect meteor echoes. Measurements from a campaign performed with a coded continuous wave SMR are shown and compared with two standard pulsed SMR measurements. The type of meteor radar described in this paper would be suited for use in a large-scale multi-static network of meteor radar transmitters and receivers. Such a system would be useful for increasing the number of meteor detections to obtain improved meteor radar data products.

  13. Coded continuous wave meteor radar

    NASA Astrophysics Data System (ADS)

    Vierinen, J.; Chau, J. L.; Pfeffer, N.; Clahsen, M.; Stober, G.

    2015-07-01

    The concept of coded continuous wave meteor radar is introduced. The radar uses a continuously transmitted pseudo-random waveform, which has several advantages: coding avoids range aliased echoes, which are often seen with commonly used pulsed specular meteor radars (SMRs); continuous transmissions maximize pulse compression gain, allowing operation with significantly lower peak transmit power; the temporal resolution can be changed after performing a measurement, as it does not depend on pulse spacing; and the low signal to noise ratio allows multiple geographically separated transmitters to be used in the same frequency band without significantly interfering with each other. The latter allows the same receiver antennas to be used to receive multiple transmitters. The principles of the signal processing are discussed, in addition to discussion of several practical ways to increase computation speed, and how to optimally detect meteor echoes. Measurements from a campaign performed with a coded continuous wave SMR are shown and compared with two standard pulsed SMR measurements. The type of meteor radar described in this paper would be suited for use in a large scale multi-static network of meteor radar transmitters and receivers. This would, for example, provide higher spatio-temporal resolution for mesospheric wind field measurements.

  14. Meteor radiant mapping with MU radar

    NASA Technical Reports Server (NTRS)

    Watanabe, Jun-Ichi; Nakamura, Tsuko; Tsuda, T.; Tsutsumi, M.; Miyashita, A.; Yoshikawa, M.

    1992-01-01

    The radiant point mapping of meteor showers with the MU radar by using a modified mapping method originally proposed by Morton and Jones (1982) was carried out. The modification is that each meteor echo was weighted by using the beam pattern of the radar system. A preliminary result of the radiant point mapping of the Geminids meteor shower in 1989 is presented.

  15. Kharkiv Meteor Radar System (the XX Age)

    NASA Astrophysics Data System (ADS)

    Kolomiyets, S. V.

    2012-09-01

    Kharkiv meteor radar research are of historic value (Kolomiyets and Sidorov 2007). Kharkiv radar observations of meteors proved internationally as the best in the world, it was noted at the IAU General Assembly in 1958. In the 1970s Kharkiv meteor automated radar system (MARS) was recommended at the international level as a successful prototype for wide distribution. Until now, this radar system is one of the most sensitive instruments of meteor radars in the world for astronomical observations. In 2004 Kharkiv meteor radar system is included in the list of objects which compose the national property of Ukraine. Kharkiv meteor radar system has acquired the status of the important historical astronomical instrument in world history. Meteor Centre for researching meteors in Kharkiv is a analogue of the observatory and performs the same functions of a generator and a battery of special knowledge and skills (the world-famous studio). Kharkiv and the location of the instrument were brand points on the globe, as the place where the world-class meteor radar studies were carried out. They are inscribed in the history of meteor astronomy, in large letters and should be immortalized on a world-wide level.

  16. Drake Antarctic Agile Meteor Radar (DrAAMER) First Results: Configuration and Comparison of Mean and Tidal Wind and Gravity Wave Momentum Flux Measurements with SAAMER

    NASA Technical Reports Server (NTRS)

    Fritts, D. C.; Janches, D.; Iimura, H.; Hocking, W. K.; Bageston, J. V.; Pene, N. M.

    2011-01-01

    A new-generation meteor radar was installed at the Brazilian Antarctic Comandante Ferraz Base (62.1degS) in March 2010. This paper describes the motivations for the radar location, its measurement capabilities, and comparisons of measured mean winds, tides, and gravity wave momentum fluxes from April to June of 2010 and 2011 with those by a similar radar on Tierra del Fuego (53.8degS). Motivations for the radars include the "hotspot" of small-scale gravity wave activity extending from the troposphere into the mesosphere and lower thermosphere (MLT) centered over the Drake Passage, the maximum of the semidiurnal tide at these latitudes, and the lack of other MLT wind measurements in this latitude band. Mean winds are seen to be strongly modulated at planetary wave and longer periods and to exhibit strong coherence over the two radars at shorter time scales as well as systematic seasonal variations. The semidiurnal tide contribute most to the large-scale winds over both radars, with maximum tidal amplitudes during May and maxima at the highest altitudes varying from approx.20 to >70 m/s. In contrast, the diurnal tide and various planetary waves achieve maximum winds of approx.10 to 20 m/s. Monthly-mean gravity wave momentum fluxes appear to reflect the occurrence of significant sources at lower altitudes, with relatively small zonal fluxes over both radars, but with significant, and opposite, meridional momentum fluxes below approx.85 km. These suggest gravity waves propagating away from the Drake Passage at both sites, and may indicate an important source region accounting in part for this "hotspot".

  17. Uncertainties in MARS Meteor Orbit Radar Data

    NASA Astrophysics Data System (ADS)

    Kolomiyets, S. V.

    2015-03-01

    The uncertainties in meteor radar data and the problem of hyperbolic meteors are interconnected. Meteor orbital data, obtained by the Meteor Automatic Radar System (MARS) at the Kharkiv Institute of Radio Electronics, Ukraine, was used to develop the algorithm to determine the uncertainties of the orbital elements obtained by radar systems such as MARS. We have constructed the empirical model of the distribution of uncertainties in the orbital elements of meteor radar data. MARS had a high effective sensitivity (the limiting magnitude of observed meteors was close to 12 ^ M) and was capable to carry out comprehensive geophysical and astronomical studies of meteors. When we register meteor numbers, radiants, meteoroid velocities, we can talk about astronomical observations. The main objective of meteor astronomy research is to determine the orbit of the meteoroid, in other words, to study a meteoroid as an astronomical object of the Solar System. Sometimes meteoroids may have an interstellar origin. Such meteoroids usually have hyperbolic orbits (i.e. with eccentricities e>1). However, hyperbolic orbits of meteoroids may have another origin, e.g. arise due to errors of observations (primarily due to the errors of eccentricities - σe). To correctly interpret the astronomical data, it is necessary to know how the errors are calculated. In this paper, we estimated the uncertainties in the Kharkiv meteor radar data (the average σe ~0.2) and discussed their connection to the problem of hyperbolic meteors. We obtained ~0.8% of total number of meteoroid orbits in 1975, which we named "real" hyperboles, i.e. with eccentricities more or equal 1+2σe.

  18. Meteor detection on ST (MST) radars

    NASA Technical Reports Server (NTRS)

    Avery, S. K.

    1987-01-01

    The ability to detect radar echoes from backscatter due to turbulent irregularities of the radio refractive index in the clear atmosphere has lead to an increasing number of established mesosphere - stratosphere - troposphere (MST or ST) radars. Humidity and temperature variations are responsible for the echo in the troposphere and stratosphere and turbulence acting on electron density gradients provides the echo in the mesosphere. The MST radar and its smaller version, the ST radar, are pulsed Doppler radars operating in the VHF - UHF frequency range. These echoes can be used to determine upper atmosphere winds at little extra cost to the ST radar configuration. In addition, the meteor echoes can supplement mesospheric data from an MST radar. The detection techniques required on the ST radar for delineating meteor echo returns are described.

  19. Analysis of ALTAIR 1998 Meteor Radar Data

    NASA Technical Reports Server (NTRS)

    Zinn, J.; Close, S.; Colestock, P. L.; MacDonell, A.; Loveland, R.

    2011-01-01

    We describe a new analysis of a set of 32 UHF meteor radar traces recorded with the 422 MHz ALTAIR radar facility in November 1998. Emphasis is on the velocity measurements, and on inferences that can be drawn from them regarding the meteor masses and mass densities. We find that the velocity vs altitude data can be fitted as quadratic functions of the path integrals of the atmospheric densities vs distance, and deceleration rates derived from those fits all show the expected behavior of increasing with decreasing altitude. We also describe a computer model of the coupled processes of collisional heating, radiative cooling, evaporative cooling and ablation, and deceleration - for meteors composed of defined mixtures of mineral constituents. For each of the cases in the data set we ran the model starting with the measured initial velocity and trajectory inclination, and with various trial values of the quantity mPs 2 (the initial mass times the mass density squared), and then compared the computed deceleration vs altitude curves vs the measured ones. In this way we arrived at the best-fit values of the mPs 2 for each of the measured meteor traces. Then further, assuming various trial values of the density Ps, we compared the computed mass vs altitude curves with similar curves for the same set of meteors determined previously from the measured radar cross sections and an electrostatic scattering model. In this way we arrived at estimates of the best-fit mass densities Ps for each of the cases. Keywords meteor ALTAIR radar analysis 1 Introduction This paper describes a new analysis of a set of 422 MHz meteor scatter radar data recorded with the ALTAIR High-Power-Large-Aperture radar facility at Kwajalein Atoll on 18 November 1998. The exceptional accuracy/precision of the ALTAIR tracking data allow us to determine quite accurate meteor trajectories, velocities and deceleration rates. The measurements and velocity/deceleration data analysis are described in Sections

  20. Observation of meteors by MST radar

    NASA Technical Reports Server (NTRS)

    Jones, William; Kingsley, S. P.

    1992-01-01

    The observation of meteor trails by a vertical mesosphere - stratosphere - troposphere (MST) radar beam has the advantage of good height resolution and an approximate knowledge of the zenith angle since the trails are horizontal or near-horizontal. An extension of the ablation theory of meteors was developed for near horizontal trails which takes into account the curvature of the earth. Observations of the Geminid meteor shower by MST radar reveal the 'diffusion heights' to be in fair agreement with the true height, but with some discrepancies that can amount to 4 km. The true heights are almost entirely confined to the range 87-91 km, although the upper limit is attributed to the coherent integration time of the existing MST radar processing.

  1. Simultaneous optical and radar observations of meteor head-echoes utilizing SAAMER

    NASA Astrophysics Data System (ADS)

    Michell, R. G.; Janches, D.; Samara, M.; Hormaechea, J. L.; Brunini, C.; Bibbo, I.

    2015-12-01

    We present simultaneous optical and radar observations of meteors observed with the Southern Argentine Agile MEteor Radar (SAAMER). Although such observations were performed in the past using High Power and Large Aperture radars, the focus here is on meteors that produced head echoes that can be detected by a significantly less sensitive but more accessible radar system. An observational campaign was conducted in August of 2011, where an optical imager was operated near the radar site in Rio Grande, Tierra del Fuego, Argentina. Six head echo events out of 150 total detections were identified where simultaneous optical meteors could also be clearly seen within the main radar beam. The location of the meteors derived from the radar interferometry agreed very well with the optical location, verifying the accuracy of the radar interferometry technique. The meteor speeds and origin directions calculated from the radar data were accurate-compared with the optics-for the 2 meteors that had radar signal-to-noise ratios above 2.5. The optical meteors that produced the head echoes had horizontal velocities in the range of 29-91 km/s. These comparisons with optical observations improve the accuracy of the radar detection and analysis techniques, such that, when applied over longer periods of time, will improve the statistics of southern hemisphere meteor observations. Mass estimates were derived using both the optical and radar data and the resulting masses agreed well with each other. All were within an order of magnitude and in most cases, the agreement was within a factor of two.

  2. Meteor radar signal processing and error analysis

    NASA Astrophysics Data System (ADS)

    Kang, Chunmei

    Meteor wind radar systems are a powerful tool for study of the horizontal wind field in the mesosphere and lower thermosphere (MLT). While such systems have been operated for many years, virtually no literature has focused on radar system error analysis. The instrumental error may prevent scientists from getting correct conclusions on geophysical variability. The radar system instrumental error comes from different sources, including hardware, software, algorithms and etc. Radar signal processing plays an important role in radar system and advanced signal processing algorithms may dramatically reduce the radar system errors. In this dissertation, radar system error propagation is analyzed and several advanced signal processing algorithms are proposed to optimize the performance of radar system without increasing the instrument costs. The first part of this dissertation is the development of a time-frequency waveform detector, which is invariant to noise level and stable to a wide range of decay rates. This detector is proposed to discriminate the underdense meteor echoes from the background white Gaussian noise. The performance of this detector is examined using Monte Carlo simulations. The resulting probability of detection is shown to outperform the often used power and energy detectors for the same probability of false alarm. Secondly, estimators to determine the Doppler shift, the decay rate and direction of arrival (DOA) of meteors are proposed and evaluated. The performance of these estimators is compared with the analytically derived Cramer-Rao bound (CRB). The results show that the fast maximum likelihood (FML) estimator for determination of the Doppler shift and decay rate and the spatial spectral method for determination of the DOAs perform best among the estimators commonly used on other radar systems. For most cases, the mean square error (MSE) of the estimator meets the CRB above a 10dB SNR. Thus meteor echoes with an estimated SNR below 10dB are

  3. The radiant distribution of AMOR radar meteors

    NASA Astrophysics Data System (ADS)

    Galligan, D. P.; Baggaley, W. J.

    2005-05-01

    A large data set provided by the highly sensitive Advanced Meteor Orbit Radar (AMOR) facility is used to investigate the structure of the sporadic meteor complex. The helion, antihelion and apex apparent sources are clearly found. Observational bias is then removed to reveal the true source distributions as observed on Earth. A long-standing problem in meteor science has been the difference in observed meteor flux between the helion and antihelion source directions. Consideration of the effects of atmospheric interference and Faraday rotation is found to lead to a closer balance between these. The orbital distributions present within the different regions are also discussed. The apex region is found to have a strong retrograde component and a weaker prograde component that exists at high southerly latitudes and that contains orbits with particularly high inclinations. The retrograde component reduces substantially after inclusion of observational bias corrections. Care should be taken in comparing the results presented here with those from other radar systems: AMOR is sensitive to dust as small in diameter as ~40μm, while the limiting sensitivity of most contemporary systems is an order of magnitude larger.

  4. Radar observations of the Volantids meteor shower

    NASA Astrophysics Data System (ADS)

    Younger, J.; Reid, I.; Murphy, D.

    2016-01-01

    A new meteor shower occurring for the first time on 31 December 2015 in the constellation Volans was identified by the CAMS meteor video network in New Zealand. Data from two VHF meteor radars located in Australia and Antarctica have been analyzed using the great circle method to search for Volantids activity. The new shower was found to be active for at least three days over the period 31 December 2015 - 2 January 2016, peaking at an apparent radiant of R.A. = 119.3 ± 3.7, dec. = -74.5 ± 1.9 on January 1st. Measurements of meteoroid velocity were made using the Fresnel transform technique, yielding a geocentric shower velocity of 28.1 ± 1.8 km s-1. The orbital parameters for the parent stream are estimated to be a = 2.11 AU, e = 0.568, i = 47.2°, with a perihelion distance of q = 0.970 AU.

  5. Physical and dynamical studies of meteors. [radar observation of fragmentation

    NASA Technical Reports Server (NTRS)

    Southworth, R. B.; Sekanina, Z.

    1974-01-01

    Distribution of meteors in streams detected in the synoptic-year meteor sample plus a study of the fragmentation characteristics of the synoptic-year meteor sample are presented. Population coefficients and dispersion coefficients were determined for each meteor stream. These two parameters serve to determine the number of definite members of the stream in the sample used, and to estimate the actual space density of meteor streams. From results of the fragmentation study, it appears that the main body of most radar meteors does not ablate fragments layer by layer, but collapses rather suddenly under dynamic pressures on the order of 0,0002 dynes/cm. Furthermore, it is believed that fragmentation does not cause a serious selection effect in the radar meteor data.

  6. Meteor radar response function: Application to the interpretation of meteor backscatter at medium frequency

    NASA Astrophysics Data System (ADS)

    Cervera, M. A.; Holdsworth, D. A.; Reid, I. M.; Tsutsumi, M.

    2004-11-01

    Recently, Cervera and Elford (2004) extended earlier work on the development of the meteor radar response function (Elford, 1964; Thomas et al., 1988) to include a nonuniform meteor ionization profile. This approach has the advantage that the height distribution of meteors expected to be observed by a radar meteor system is able to be accurately modeled and insights into the meteoroid chemistry to be gained. The meteor radar response function is also an important tool with regard to the interpretation of meteor backscatter in other areas, e.g., modeling the expected diurnal variation of sporadic meteors, investigating the expected echo distribution over the sky, and the calculation of the expected rate curves of meteor showers. We exemplify each of these techniques from the analysis of meteor data collected by the Buckland Park 2 MHz system during October 1997. In addition, we show that the response function may be used to quantify the echo rate of a given shower relative to the sporadic background and thus determine if that shower is able to be detected by the radar.

  7. Optical and Radar Measurements of the Meteor Speed Distribution

    NASA Technical Reports Server (NTRS)

    Moorhead, A. V.; Brown, P. G.; Campbell-Brown, M. D.; Kingery, A.; Cooke, W. J.

    2016-01-01

    The observed meteor speed distribution provides information on the underlying orbital distribution of Earth-intersecting meteoroids. It also affects spacecraft risk assessments; faster meteors do greater damage to spacecraft surfaces. Although radar meteor networks have measured the meteor speed distribution numerous times, the shape of the de-biased speed distribution varies widely from study to study. Optical characterizations of the meteoroid speed distribution are fewer in number, and in some cases the original data is no longer available. Finally, the level of uncertainty in these speed distributions is rarely addressed. In this work, we present the optical meteor speed distribution extracted from the NASA and SOMN allsky networks [1, 2] and from the Canadian Automated Meteor Observatory (CAMO) [3]. We also revisit the radar meteor speed distribution observed by the Canadian Meteor Orbit Radar (CMOR) [4]. Together, these data span the range of meteoroid sizes that can pose a threat to spacecraft. In all cases, we present our bias corrections and incorporate the uncertainty in these corrections into uncertainties in our de-biased speed distribution. Finally, we compare the optical and radar meteor speed distributions and discuss the implications for meteoroid environment models.

  8. Moving target detection for frequency agility radar by sparse reconstruction

    NASA Astrophysics Data System (ADS)

    Quan, Yinghui; Li, YaChao; Wu, Yaojun; Ran, Lei; Xing, Mengdao; Liu, Mengqi

    2016-09-01

    Frequency agility radar, with randomly varied carrier frequency from pulse to pulse, exhibits superior performance compared to the conventional fixed carrier frequency pulse-Doppler radar against the electromagnetic interference. A novel moving target detection (MTD) method is proposed for the estimation of the target's velocity of frequency agility radar based on pulses within a coherent processing interval by using sparse reconstruction. Hardware implementation of orthogonal matching pursuit algorithm is executed on Xilinx Virtex-7 Field Programmable Gata Array (FPGA) to perform sparse optimization. Finally, a series of experiments are performed to evaluate the performance of proposed MTD method for frequency agility radar systems.

  9. Determination of the structure of meteor showers from radar observations.

    NASA Astrophysics Data System (ADS)

    Kolomiets, S. V.; Milyutchenko, I. A.

    1995-08-01

    A method for the determination of the parameter s for meteor mass distribution and meteor shower number density from radar measurements of meteor quantities during shower activities is considered. The data from radar observations of η Aquarids and Orionids in Khar'kov in 1986 are analyzed with this method. For the duration of both showers, the maximum activity of the parameter s is found to be equal to 1.65. The dependencies of the number densities of the meteor showers and of the parameter s on the solar longitude and the time of observation are also derived. The mean number density of meteor bodies with M ≥ 10-3g is equal to 2.9×10-11m-2s-1 for the η Aquarids and 2.5×10-11m-2s-1 for the Orionids.

  10. About comparative models of meteor orbital data for different radars

    NASA Astrophysics Data System (ADS)

    Kolomiyets, Svitlana

    2016-07-01

    There is an electronic data base (~ 250, 000 orbits of faint radar meteors till +12^M) in the Kashcheyev LAB of KhNURE (Kharkiv, Ukraine). It is important if this data base will become open. Two scientific teams (from New Zealand and from Canada) are the principal expert on similar radar dataset (~500,000 and more than 3 million, respectively). The Kharkiv team will prepare the data for implementation in the IAU Meteor Data Centre and the virtual Observatory. We will develop a standard model for comparison of data from different radars.

  11. The KUT meteor radar: An educational low cost meteor observation system by radio forward scattering

    NASA Astrophysics Data System (ADS)

    Madkour, W.; Yamamoto, M.

    2016-01-01

    The Kochi University of Technology (KUT) meteor radar is an educational low cost observation system built at Kochi, Japan by successive graduate students since 2004. The system takes advantage of the continuous VHF- band beacon signal emitted from Fukui National College of Technology (FNCT) for scientific usage all over Japan by receiving the forward scattered signals. The system uses the classical forward scattering setup similar to the setup described by the international meteor organization (IMO), gradually developed from the most basic single antenna setup to the multi-site meteor path determination setup. The primary objective is to automate the observation of the meteor parameters continuously to provide amounts of data sufficient for statistical analysis. The developed software system automates the observation of the astronomical meteor parameters such as meteor direction, velocity and trajectory. Also, automated counting of meteor echoes and their durations are used to observe mesospheric ozone concentration by analyzing the duration distribution of different meteor showers. The meteor parameters observed and the methodology used for each are briefly summarized.

  12. Radar and Meteors: Controversy over the Origin of Meteors in Postwar Astronomy

    NASA Astrophysics Data System (ADS)

    Sullivan, Woodruff T., III

    2006-12-01

    After World War II radio physicists and engineers discovered that radar reflections were readily obtained off the ionized trails left by meteors. The group led by Bernard Lovell at the Jodrell Bank Experimental Station of Manchester University, England, led the effort to design radar transmitters, receivers, and antenna systems that could better understand these reflections. First, an entire suite of daytime meteor showers was found to accompany the familiar nighttime showers. Next, associating with meteor astronomers such as Fred Whipple, Ernst Öpik, and Cuno Hoffmeister, Lovell found that his radar data could contribute to a longstanding controversy in the field: was there any portion of the meteors whose speeds indicated that they were on hyperbolic orbits and therefore of interstellar origin (i.e., >72 km/s), or did all meteoroids originate within the solar system? By 1953 the Jodrell Bank radar astronomers’ huge samples of echoes and measured speeds of meteors indicated that there were in fact no interstellar interlopers. This settled the question for most workers in the field, although Opik and Hoffmeister did not give in.

  13. Rapid decrease of radar cross section of meteor head echo observed by the MU radar

    NASA Astrophysics Data System (ADS)

    Nakamura, T.; Nishio, M.; Sato, T.; Tsutsumi, S.; Tsuda, T.; Fushimi, K.

    The meteor head echo observation using the MU (Middle and Upper atmosphere) radar (46.5M Hz, 1MW), Shigaraki, Japan, was carried out simultaneously with a high sensitive ICCD (Image-intensified CCD) camera observation in November 2001. The time records were synchronized using GPS satellite signals, in order to compare instantaneous radar and optical meteor magnitudes. 26 faint meteors were successfully observed simultaneously by both equipments. Detailed comparison of the time variation of radar echo intensity and absolute optical magnitude showed that the radar scattering cross section is likely to decrease rapidly by 5 - 20 dB without no corresponding magnitude variation in the optical data. From a simple modeling, we concluded that such decrease of RCS (radar cross section ) is probably due to the transition from overdense head echo to underd ense head echo.

  14. The 50-MHz meteor radar observation at Syowa Station, Antarctica

    NASA Technical Reports Server (NTRS)

    Tanaka, T.; Ogawa, T.; Igarashi, K.; Fujii, R.

    1985-01-01

    The 50-MHz Doppler radar installed at Syowa Station (69 deg 00'S, 39 deg 35'E), Antarctica, in 1982 can detect continuously a meteor echo if an operator assigns the meteor mode operation to the radar. The radar has two narrow antenna beams (4 deg in the horizontal plane), one toward geomagnetic south and the other toward approximately geographic south, with a crossing angle of about 33 deg. The minicomputer annexed to the radar controls the transmission and reception of a 50-MHz wave. If the receiver detects a meteor echo, the flag signal is sent to the computer. Then the computer begins to determine the echo range with a time resolution of 1 micro s and to sample every 200 microns/s for 1 s the Doppler signal and echo intensity at the particular range (R). The line-of-sight velocity (V sub D) of the echo trail is calculated from the output from the Doppler signal detection circuit having an offset frequency by using the so-called zero-crossing method. The echo amplitude decay time calculated by a least-mean square method is used to obtain the ambipolar diffusion coefficient (D) and then to calculate the echo height (H). About 120 day observations were made during 1982-1983. Some early results are presented. magnetic tapes together with V sub D, D, H and R for later analysis in Japan. About 120 day observation were made during 1982-1983. Some early results are presented.

  15. Characterization of Non-Specular Meteor Trail Radar Detections from Non-Field-Aligned Irregularities

    NASA Astrophysics Data System (ADS)

    Tarano, A. M.; Close, S.; Janches, D.

    2015-12-01

    Meteoroids enter the Earth's atmosphere and are detected by radars as they ablate between 140 and 70 km altitude in the E-region of the ionosphere. The radar returns are classified as head echoes, the plasma surrounding the meteoroids, and trails, the expanding plasma column left in the meteoroid's wake. In addition, plasma trails are categorized by the angle between the meteoroid's trajectory and the radar beam. One type is the specular trail, which occurs when the meteoroid travels quasi-perpendicular to the beam. The second type, non-specular trail, is independent of trajectory but, according to our current understanding, the radar beam must be perpendicular to the Earth's magnetic field in order to reflect from field-aligned irregularities (FAI) after the onset of plasma turbulence. However, the Southern Argentina Agile Meteor Radar (SAAMER) has surprisingly detected 25 cases of non-specular trails over a period of 12 days in 2011. At the radar's location, the geomagnetic field is about 51 degrees with respect to the radar beam, which suggests that our present theory of the physics behind non-specular trail formation is lacking. We present interferometric results from the observations performed using SAAMER in order to demonstrate that the non-specular trails detected are due to reflections from non-FAI. We examine the detected trail duration dependence on altitude, meteoroid velocity, time of day, and various geometric relationships to establish that the plasma turbulence mainly arises from gradient drift and wind driven instabilities. Moreover, the latter parameters are compared to traditional non-specular trail observations from an equatorial high-power large aperture radar, ARPA Long-Range Tracking and Instrumentation Radar (ALTAIR), to contextualize the detections accomplished by SAAMER.

  16. A decadal survey of the Daytime Arietid meteor shower using the Canadian Meteor Orbit Radar

    NASA Astrophysics Data System (ADS)

    Bruzzone, J. S.; Brown, P.; Weryk, R. J.; Campbell-Brown, M. D.

    2015-01-01

    We present results from a 12 year survey of the Daytime Arietid meteor shower using the Canadian Meteor Orbit Radar, a VHF backscattering orbital meteor radar, covering the interval 2002-2013. This survey recorded more than 2 × 104 Daytime Arietid orbits having representative masses of 8 × 10-8 kg and sizes of ≈0.4 mm. The core activity for the Arietids is found in the range 73.5° ≤ λ⊙ ≤ 84.5° and shows a broad 4-d maximum centred near λ⊙ = 80.5° of 0.04 meteoroids km-2 h-1 producing meteors of equivalent radio magnitude of +6.5 from a mean radiant at αg = 44.9° ± 1.1°, δg = 25.5° ± 1 .0°. During the plateau of shower peak activity, the mass index of the stream reaches a minimum with s = 1.6-1.7. Contamination from another nearby shower (likely the Daytime Zeta Perseids) and/or sub-streams showing different orbits compared to the core of the stream is evident in the interval 60.5° ≤ λ⊙ ≤ 71.5°. Similar contamination beyond λ⊙ = 84.5° may be due to the Helion sporadic source. We also characterized the deceleration profiles for Daytime Arietid meteor echoes using several independent speed techniques including Fresnel pre-t0, Fresnel amplitude oscillation and time-of-flight speeds which together with modelling produced a best estimate for the stream's out-of-atmosphere speed of v∞ = 40.5 ± 0.7 km s-1. The mean radar orbit from our study is noticeably smaller in semi-major axis and eccentricity than is found for larger Arietids measured with optical systems, a difference which if real indicates a particle-size sorting of the stream orbit. The broad activity maximum, long duration of activity and particle-size dependence of the orbital elements suggest the stream is too old to have been solely formed during the breakup of the parent comet of the Marsden sunskirters about a millennium ago as proposed by Sekanina & Chodas.

  17. Measurement of momentum flux using two meteor radars in Indonesia

    NASA Astrophysics Data System (ADS)

    Matsumoto, Naoki; Shinbori, Atsuki; Riggin, Dennis M.; Tsuda, Toshitaka

    2016-03-01

    Two nearly identical meteor radars were operated at Koto Tabang (0.20° S, 100.32° E), West Sumatra, and Biak (1.17° S, 136.10° E), West Papua, in Indonesia, separated by approximately 4000 km in longitude on the Equator. The zonal and meridional momentum flux, u'w' and v'w', where u, v, and w are the eastward, northward, and vertical wind velocity components, respectively, were estimated at 86 to 94 km altitudes using the meteor radar data by applying a method proposed by Hocking (2005). The observed u'w' at the two sites agreed reasonably well at 86, 90, and 94 km during the observation periods when the data acquisition rate was sufficiently large enough. Variations in v'w' were consistent between 86, 90, and 94 km altitudes at both sites. The climatological variation in the monthly averaged u'w' and v'w' was investigated using the long-term radar data at Koto Tabang from November 2002 to November 2013. The seasonal variations in u'w' and v'w' showed a repeatable semiannual and annual cycles, respectively. u'w' showed eastward values in February-April and July-September and v'w' was northward in June to August at 90-94 km, both of which were generally anti-phase with the mean zonal and meridional winds, having the same periodicity. Our results suggest the usefulness of the Hocking method.

  18. Novel Methods for 3D Numerical Simulation of Meteor Radar Reflections

    NASA Astrophysics Data System (ADS)

    Räbinä, J.; Mönkölä, S.; Rossi, T.; Markkanen, J.; Gritsevich, M.; Muinonen, K.

    2016-08-01

    We model the radar reflections in a three-dimensional space as time-harmonic electromagnetic scattering from plasmatic obstacles. We introduce two novel methods for numerical simulation of meteor radar reflections.

  19. A Intercomparison of Interferometric Meteor Radar Calibration Techniques

    NASA Astrophysics Data System (ADS)

    Kang, C.; Palo, S.

    Interferometric techniques are commonly used in all-sky meteor radar systems to determine the meteors position in the sky Before correctly conducting the task of estimating the direction-of-arrival DOA of the meteors effective and reliable calibrating the phases of the system is required Although different methods have been reported there is no satisfactory technique published This study thoroughly discusses the current and prospective calibration techniques Generally speaking phase calibration is implemented by measuring the phase difference between the receivers for a signal produced by a source with known locations Next the phase offsets can be estimated by comparing the measured phase difference with the expected phase difference between the antenna pairs Use of a low elevation ground antenna was reported by Valentic 1997 as the calibration source to estimate the receiver s phase offsets The advantage of this method is that the antennas can be mounted easily moved to a range of azimuths Measurements from these positions can thus be averaged to increase the accuracy of the estimated phase offsets However the angle estimation error at low elevation angles is larger than at high elevation angles which will degrade the performance of the calibration technique Unmanned vehicle UAV because of the low cost and operating flexibility received more concerns recently and is under development for autonomous antenna calibration Pisano et al 2005 This approach requires a robust navigation system in addition to GPS for system

  20. The effects of deionization processes on meteor radar diffusion coefficients below 90 km

    NASA Astrophysics Data System (ADS)

    Younger, J. P.; Lee, C. S.; Reid, I. M.; Vincent, R. A.; Kim, Y. H.; Murphy, D. J.

    2014-08-01

    The decay times of VHF radar echoes from underdense meteor trails are reduced in the lower portions of the meteor region. This is a result of plasma neutralization initiated by the attachment of positive trail ions to neutral atmospheric molecules. Decreased echo decay times cause meteor radars to produce erroneously high estimates of the ambipolar diffusion coefficient at heights below 90 km, which affects temperature estimation techniques. Comparisons between colocated radars and satellite observations show that meteor radar estimates of diffusion coefficients are not consistent with estimates from the Aura Microwave Limb Sounder satellite instrument and that colocated radars operating at different frequencies estimate different values of the ambipolar diffusion coefficient for simultaneous detections of the same meteors. Loss of free electrons from meteor trails due to attachment to aerosols and chemical processes were numerically simulated and compared with observations to determine the specific mechanism responsible for low-altitude meteor trail plasma neutralization. It is shown that three-body attachment of positive metal ions significantly reduces meteor radar echo decay times at low altitudes compared to the case of diffusion only that atmospheric ozone plays little part in the evolution of low-altitude underdense meteor trails and that the effect of three-body attachment begins to exceed diffusion in echo decay times at a constant density surface.

  1. Preliminary design study of a high resolution meteor radar

    NASA Technical Reports Server (NTRS)

    Lee, W.; Geller, M. A.

    1973-01-01

    A design study for a high resolution meteor radar system is carried out with the objective of measuring upper atmospheric winds and particularly studying short period atmospheric waves in the 80 to 120 km altitude region. The transmitter that is to be used emits a peak power of 4 Mw. The system is designed to measure the wind velocity and height of a meteor trail very accurately. This is achieved using a specially developed digital reduction procedure to determine wind velocity and range together with an interferometer for measuring both the azimuth and elevation angles of the region with a long baseline vernier measurement being used to refine the elevation angle measurement. The resultant accuracies are calculated to be + or - 0.9 m/s for the wind, + or - 230 m for the range and + or - 0.12 deg for the elevation angle, giving a height accuracy of + or - 375 m. The prospects for further development of this system are also discussed.

  2. Effects of meteor head plasma distribution on radar cross sections and derived meteoroid masses

    NASA Astrophysics Data System (ADS)

    Marshall, R. A.; Close, S.; Brown, P.; Dimant, Y.

    2016-01-01

    We present calculations that relate meteor head echo radar cross sections to the meteor head plasma distribution. We use a forward model of radar scattering from meteor plasma using a finite-difference time-domain (FDTD) model of the electromagnetic wave interaction with the plasma. This model computes the meteor head RCS for a given meteor plasma distribution, specified with a peak plasma density and a characteristic size. We then relate measured RCS values to the input size and density parameters to better characterize the meteor plasma. We present simulation results that show that the RCS is directly related to the overdense meteor area; that is, the cross-section area of the meteor inside which the plasma frequency exceeds the radar frequency. This provides a direct estimate of the meteor plasma size from a given RCS measurement. Next we investigate the effect of the assumed plasma distribution. We study the RCS resulting from Gaussian, parabolic exponential and 1/r2 distributions. Comparing the different calculated RCS from these different distributions to three-frequency head echo data from the CMOR radar, we show that the 1/r2 distribution provides the best fit to the data. However, given uncertainties in the data, we cannot conclude that any distribution is the most valid. In addition, we show that the choice of distribution assumed can alter the resulting line density q by an order of magnitude for the same data.

  3. Mesospheric observations by a forward scattering meteor radar basic setup

    NASA Astrophysics Data System (ADS)

    Madkour, Waleed; Yamamoto, Masa-yuki

    2016-08-01

    The durations of radio echo signals scattered from meteor ionized trails might not show a consistent increase corresponding to higher density trails due to the rapid removal of meteor ions at certain heights. Several studies have concluded the dominant role of the secondary ozone layer over diffusion in the removal of the meteor trails below 95 km through chemical oxidization of the meteor ions. Using a basic setup configuration of a forward scattering receiver, a trial to observe the mesospheric ozone concentration was performed by analyzing the meteor echo duration distributions. The forward scattered meteor echoes have the advantage of long durations that can enable observing the transition from the diffusion-removal regime to the chemistry-removal regime. The cumulative meteor echo duration distribution of two meteor showers, the Perseids and the Geminids, were analyzed over 10 years and the chemistry-removal regime in each shower was observed. The knee duration position at which a drop in the number of long overdense meteor echoes starts differed by around 30 seconds between the two showers. As the secondary ozone concentration is inversely related to the solar activity level, the Geminids 2011 corresponding to a high solar activity level showed a significant higher counts of long duration echoes compared to the Geminids 2006 during a low activity level, with the knee position shifted to longer duration. The knee positions obtained during the two distinct meteor showers and the two half solar cycle points are generally in agreement with the mesospheric ozone conditions expected in each case. However, continuous data record is required for the other meteor showers and the sporadic meteors at different heights to observe the mesospheric ozone concentration vertically and the full 11-years solar cycle.

  4. Agile beam laser radar using computational imaging for robotic perception

    NASA Astrophysics Data System (ADS)

    Powers, Michael A.; Stann, Barry L.; Giza, Mark M.

    2015-05-01

    This paper introduces a new concept that applies computational imaging techniques to laser radar for robotic perception. We observe that nearly all contemporary laser radars for robotic (i.e., autonomous) applications use pixel basis scanning where there is a one-to-one correspondence between world coordinates and the measurements directly produced by the instrument. In such systems this is accomplished through beam scanning and/or the imaging properties of focal-plane optics. While these pixel-basis measurements yield point clouds suitable for straightforward human interpretation, the purpose of robotic perception is the extraction of meaningful features from a scene, making human interpretability and its attendant constraints mostly unnecessary. The imposing size, weight, power and cost of contemporary systems is problematic, and relief from factors that increase these metrics is important to the practicality of robotic systems. We present a system concept free from pixel basis sampling constraints that promotes efficient and adaptable sensing modes. The cornerstone of our approach is agile and arbitrary beam formation that, when combined with a generalized mathematical framework for imaging, is suited to the particular challenges and opportunities of robotic perception systems. Our hardware concept looks toward future systems with optical device technology closely resembling modern electronically-scanned-array radar that may be years away from practicality. We present the design concept and results from a prototype system constructed and tested in a laboratory environment using a combination of developed hardware and surrogate devices for beam formation. The technological status and prognosis for key components in the system is discussed.

  5. A processing method and results of meteor shower radar observations

    NASA Technical Reports Server (NTRS)

    Belkovich, O. I.; Suleimanov, N. I.; Tokhtasjev, V. S.

    1987-01-01

    Studies of meteor showers permit the solving of some principal problems of meteor astronomy: to obtain the structure of a stream in cross section and along its orbits; to retrace the evolution of particle orbits of the stream taking into account gravitational and nongravitational forces and to discover the orbital elements of its parent body; to find out the total mass of solid particles ejected from the parent body taking into account physical and chemical evolution of meteor bodies; and to use meteor streams as natural probes for investigation of the average characteristics of the meteor complex in the solar system. A simple and effective method of determining the flux density and mass exponent parameter was worked out. This method and its results are discussed.

  6. Modeling the Meteoroid Input Function at Mid-Latitude Using Meteor Observations by the MU Radar

    NASA Technical Reports Server (NTRS)

    Pifko, Steven; Janches, Diego; Close, Sigrid; Sparks, Jonathan; Nakamura, Takuji; Nesvorny, David

    2012-01-01

    The Meteoroid Input Function (MIF) model has been developed with the purpose of understanding the temporal and spatial variability of the meteoroid impact in the atmosphere. This model includes the assessment of potential observational biases, namely through the use of empirical measurements to characterize the minimum detectable radar cross-section (RCS) for the particular High Power Large Aperture (HPLA) radar utilized. This RCS sensitivity threshold allows for the characterization of the radar system s ability to detect particles at a given mass and velocity. The MIF has been shown to accurately predict the meteor detection rate of several HPLA radar systems, including the Arecibo Observatory (AO) and the Poker Flat Incoherent Scatter Radar (PFISR), as well as the seasonal and diurnal variations of the meteor flux at various geographic locations. In this paper, the MIF model is used to predict several properties of the meteors observed by the Middle and Upper atmosphere (MU) radar, including the distributions of meteor areal density, speed, and radiant location. This study offers new insight into the accuracy of the MIF, as it addresses the ability of the model to predict meteor observations at middle geographic latitudes and for a radar operating frequency in the low VHF band. Furthermore, the interferometry capability of the MU radar allows for the assessment of the model s ability to capture information about the fundamental input parameters of meteoroid source and speed. This paper demonstrates that the MIF is applicable to a wide range of HPLA radar instruments and increases the confidence of using the MIF as a global model, and it shows that the model accurately considers the speed and sporadic source distributions for the portion of the meteoroid population observable by MU.

  7. A MATLAB-based planar array design assistant package with applications to meteor radar systems

    NASA Astrophysics Data System (ADS)

    Kang, C.; Palo, S.

    Interferometric techniques are commonly used in all-sky meteor radar systems for meteor location determination Essentially interferometric techniques use the phase information recorded from different receiving antennas to estimate the elevation and azimuth of the meteors Prior efforts have been made to determine an antenna geometry that improves the performance of meteor radar systems For example Hocking and Thayaparan 1997 used four antennas typically spaced by 1 5 to 3 wavelengths to locate the meteors Jones 1992 and Hocking 1997 presented an antenna geometry using a 5 element array with minimum antenna spacing of 2 wavelengths to estimate the direction of arrival DOA of the meteors By spacing the antennas more than 2 wavelength apart these array geometries were successful in reducing the electromagnetic coupling effect between the antennas which can introduce errors in the estimation of meteor locations Without a clear metric for performance it is difficult to compare geometries In this work a MATLAB planar antenna array package mainly designed for visualization of the direction of arrival DOA estimation performance of arbitrary user designed antenna array is presented Performance comparisons of nominal array geometries are also provided Several metrics are available in this package in an effort to provide the user with a comprehensive examination of an array s performance The metrics are the Cramer-Rao bound CRB which is the minimum variance that can be obtained for any unbiased estimator the co-array the

  8. A meteoroid stream survey using the Canadian Meteor Orbit Radar - III. Mass distribution indices of six major meteor showers

    NASA Astrophysics Data System (ADS)

    Blaauw, R. C.; Campbell-Brown, M. D.; Weryk, R. J.

    2011-07-01

    The mass distribution index of the Geminid, Quadrantid, Arietid, Eta Aquariid, Orionid and South Delta Aquariid meteor showers have been measured using data from 2007 to 2010 from the Canadian Meteor Orbit Radar (CMOR). Single-station data from the 29.85-MHz system were used to find mass index as a function of solar longitude, and to compare separate years of showers. The variation in mass index with solar longitude can provide information on the structure of the stream and how the structure changes with time. The Geminids and Quadrantids were the most prominent showers seen by CMOR, and had peak mass indices of 1.65 and 1.55, respectively. They had clear, strong peaks and little year-to-year variation. The other showers had slightly higher peak mass indices and a greater variability, even though a more sporadic contamination, which might have affected the results.

  9. Analysis of Coherent Scatter Observations collected with the new Penn State VHF Meteor Radar

    NASA Astrophysics Data System (ADS)

    Urbina, J. V.; Hackett, A. L.; Dyrud, L. P.; Fentzke, J.

    2012-12-01

    The Penn State University 50 MHz radar interferometer has been installed near Penn State campus, University Park, Pennsylvania (77.97°W, 40.70°N), to make continuous meteor observations since July 5, 2012. The antenna beam is pointed to the north in the magnetic meridian plane. In azimuth the half-power beam-width is about 3.4o, while in elevation the gain pattern peaked in the direction perpendicular to the geomagnetic field at E-region heights at about 18o elevation angle. The system uses two phased sub-arrays of four 24-element COCO strings with an east-west separation of 50 m. On transmission both sub-arrays are excited simultaneously and oriented perpendicular to the Earth's geomagnetic field lines at E- region heights. On reception each sub-array is sampled independently for interferometric detection of the scattering regions. The new radar operates at a peak power of about 30 kW and can detect all three types of meteor reflections: 1) the commonly used specular meteor trails; 2) non-specular trails, which result from plasma instability and turbulence generated field aligned irregularities (FAI); and 3) meteor head-echoes, which are a radar target moving at the speed of the meteoroid. In this paper, we present first observational trends of specular, non- specular, and head-echoes collected with the new system and discuss sampling biases of each meteor observation technique. We also present the general characteristics of continuous measurements of E-region and F-region coherent echoes using this modern radar system and compare them with coherent radar events observed at other geographic mid-latitude radar stations.

  10. The New Meteor Radar at Penn State: Design and First Observations

    NASA Technical Reports Server (NTRS)

    Urbina, J.; Seal, R.; Dyrud, L.

    2011-01-01

    In an effort to provide new and improved meteor radar sensing capabilities, Penn State has been developing advanced instruments and technologies for future meteor radars, with primary objectives of making such instruments more capable and more cost effective in order to study the basic properties of the global meteor flux, such as average mass, velocity, and chemical composition. Using low-cost field programmable gate arrays (FPGAs), combined with open source software tools, we describe a design methodology enabling one to develop state-of-the art radar instrumentation, by developing a generalized instrumentation core that can be customized using specialized output stage hardware. Furthermore, using object-oriented programming (OOP) techniques and open-source tools, we illustrate a technique to provide a cost-effective, generalized software framework to uniquely define an instrument s functionality through a customizable interface, implemented by the designer. The new instrument is intended to provide instantaneous profiles of atmospheric parameters and climatology on a daily basis throughout the year. An overview of the instrument design concepts and some of the emerging technologies developed for this meteor radar are presented.

  11. Shigaraki middle and upper atmosphere radar meteor-head-echo database

    NASA Astrophysics Data System (ADS)

    Kero, J.; Nakamura, T.; Szasz, C.; Kastinen, D.; Watanabe, J.; Yamamoto, M.; Fujiwara, Y.; Abo, M.; Tanaka, Y.; Abe, S.

    2014-07-01

    Introduction: Mass infux from space into the terrestrial atmosphere is mainly caused by meteors. Meteors deliver various elements into the atmosphere and the meteoric dust particles are of great importance in the terrestrial atmosphere. For example, they act as nucleus for condensation and clouds and affect various atmospheric phenomena both in physical and chemical aspects. Thus, to investigate the meteor flux, orbits and their interactions in the upper atmosphere is very important but at the same time the method of investigation is limited, especially for precise measurements. High-power large-aperture (HPLA) radar observation is a recent technique to provide useful information on meteor infux and orbits, as well as interactions with the atmosphere. Since 2009 orbital data of about 120,000 meteors [2] have been collected using a novel head-echo analysis algorithm for the lower VHF band [1]. The data was collected using the middle and upper atmosphere radar (MU radar) of Kyoto University at Shigaraki (34.9N, 136.1S). The MU radar is a large atmospheric VHF radar with 46.5 MHz frequency, 1 MW output transmission power and 8330 m^2 aperture array antenna. An open database (MU radar meteor head echo database: MURMHED) for research and education is now being created. Database: The database currently holds 53 different parameters for each event and a number of associated time series consisting of range, height, radar cross section, signal to noise ratio, radial velocity and meteorid velocity. The database parameters are MJD, Year [UT], Month [UT], Day [UT], Hour [UT], Minute [UT], Second [UT], Duration [s], RA [deg], Dec [deg], Az [deg], Ze [deg], Az uncorr [deg], Ze uncorr [deg], Ze correction [deg], Obs initial vel [km/s], Geocentric vel [km/s], RCS [dBsm], SNR [dB], Start hgt [km], End hgt [km], Az of start point [deg], Ze of start point [deg], Az of end point [deg], Ze of end point [deg], Semimajor axis [au], Eccentricity, Perihelion dist [au], Lon of asc node [deg

  12. Meteoroid Streams at Earth Detected by the Canadian Meteor Orbit Radar

    NASA Astrophysics Data System (ADS)

    Brown, Peter G.; Weryk, R. J.; Wong, D. K.; Jones, J.

    2007-10-01

    The Canadian Meteor Orbit Radar (CMOR) is a multi-frequency backscatter meteor radar which has been in routine operation since 1999, with an orbit measurement capability since 2002. In total, CMOR has measured over 5 million orbits of meteoroids with masses greater than 10 micrograms, while recording more than 20 million meteor echoes in total to mid-2007. We have applied a two stage comparative technique for identifying meteor showers in CMOR data. In the first stage, showers are delineated using single station echo directions to compute apparent radiant activity per degree of solar longitude. A second stage employs quasi 3D wavelet transforms to examine clustering of individually measured geocentric radiants and velocities based on measured orbits detected per degree of solar longitude. From this analysis we have identified 44 annual minor and major meteor showers with high reliability. A dozen of these showers are previously unreported in the literature. We find that several streams reported as distinct in the literature are in fact continuously active over long time periods. Most prominent among these are the Iota Aquariid /Piscid / Taurid showers of August - November all of which are part of one stream linked to the broad 2P/Encke meteoroid complex. Several of our newly reported streams occur in regions of aei space with few or no obvious parent bodies. In particular, many streams have i 90 degs and a 1 AU with e > 0.6. These showers are rich in faint meteors and suggestive of evolutionary processes driven by Poynting-Robertson drag separating meteoroids from original parent body orbits. We also report details from our radar survey of a number of newly recognized cometary dust trails which intersect the Earth defining orbital elements of unrecognized potentially hazardous comets or extinct cometary nuclei.

  13. Fragmentation of specular overdense meteor trail echoes observed with Gadanki MST radar

    NASA Astrophysics Data System (ADS)

    Chenna Reddy, K.; Yellaiah, G.

    2016-02-01

    The pulse-integrated signal to noise ratio as a function of time known as radar meteor light curve (analogous to optical light curve), is an indicative of ablation processes during meteoroid flight in the atmosphere. In this study, we present and discuss few examples of light curves of long duration specular overdense meteor echoes detected with 53 MHz Gadanki (13.5°N, 79.2°E) MST radar. These echoes are of several seconds duration, where pulsation in amplitude is about ten cycles within few seconds. This means the fluctuations in amplitude are much slower than typical Fresnel oscillations of underdense as well as the head echo fluctuations. These light curves reveal several features unreported previously in the radar meteor returns that are consistent with meteoroid fragmentation. Some of them provide the strong observational evidence of a sub-millimeter-sized meteoroid, breaking apart into two distinct fragments. The pulsations in light curves are interpreted as being due to interference from two distinct scattering centers. Some other meteor events such as meteoroids undergoing quasi-continuous disintegration are also discussed.

  14. The analyses of destruction of the meteoric trail on radar observations.

    NASA Astrophysics Data System (ADS)

    Karpov, A. V.; Naumov, A. V.; Abrosimov, J. V.

    2003-04-01

    It is known, that ambipolar diffusion defines a destruction of an ionic-electronic trail of underdence type. At the same time attempts of an explanation of destruction of overdence trail by only ambipolar diffusion give large deviations of definition of duration of the meteoric trail. Reduction of duration of existence of the meteoric trail was explained by influence of change of parameter s in distribution of meteoric bodies on weights; influence of effects recombination; to adhere of electrons to the neutral molecules, atoms and turbulent diffusion. The analysis of works of this problem gives, that researchers do not have the good explanation of processes of destruction of the meteoric trail. In this work we try to define the most important processes of destruction of the overdence meteoric trail and to construct model of destruction of an meteoric trail. The analysis of rate of reactions shows, that procesess of the recombination with electronic stabilization, dissociative recombination, two-step process with participation of atmospheric ozone also influence on reduction of concentration of electronic in trail. In view of these reactions we have written down the equation for change of electronic density of a trace. The decision of the given equation was carried out in approach, that distribution of electronic density on section of a trace is Gauss and does not vary in due course. We constructed modeling distributions of duration radioreflections at the account of action only one of mechanisms and their combination. The qualitative analysis ions structure of a trace is carried out. As the initial data the average structure of meteoric bodies is taken according to previous works of different authors and factors of ionization of these atoms for speeds from 20 km/s up to 70 km/s. For acknowledgement of theoretical hypotheses experimental supervision on meteoric radar KSU-5 are planned.

  15. DYNAMICS OF DUST PARTICLES RELEASED FROM OORT CLOUD COMETS AND THEIR CONTRIBUTION TO RADAR METEORS

    SciTech Connect

    Nesvorny, David; Vokrouhlicky, David; Pokorny, Petr; Janches, Diego

    2011-12-10

    The Oort Cloud Comets (OCCs), exemplified by the Great Comet of 1997 (Hale-Bopp), are occasional visitors from the heatless periphery of the solar system. Previous works hypothesized that a great majority of OCCs must physically disrupt after one or two passages through the inner solar system, where strong thermal gradients can cause phase transitions or volatile pressure buildup. Here we study the fate of small debris particles produced by OCC disruptions to determine whether the imprints of a hypothetical population of OCC meteoroids can be found in the existing meteor radar data. We find that OCC particles with diameters D {approx}< 10 {mu}m are blown out from the solar system by radiation pressure, while those with D {approx}> 1 mm have a very low Earth-impact probability. The intermediate particle sizes, D {approx} 100 {mu}m, represent a sweet spot. About 1% of these particles orbitally evolve by Poynting-Robertson drag to reach orbits with semimajor axis a {approx} 1 AU. They are expected to produce meteors with radiants near the apex of Earth's orbital motion. We find that the model distributions of their impact speeds and orbits provide a good match to radar observations of apex meteors, except for the eccentricity distribution, which is more skewed toward e {approx} 1 in our model. Finally, we propose an explanation for the long-standing problem in meteor science related to the relative strength of apex and helion/antihelion sources. As we show in detail, the observed trend, with the apex meteors being more prominent in observations of highly sensitive radars, can be related to orbital dynamics of particles released on the long-period orbits.

  16. Dynamics of Dust Particles Released from Oort Cloud Comets and Their Contribution to Radar Meteors

    NASA Technical Reports Server (NTRS)

    Nesvorny, David; Vokrouhlicky, David; Pokorny, Petr; Janches, Diego

    2012-01-01

    The Oort Cloud Comets (OCCs), exemplified by the Great Comet of 1997 (Hale-Bopp), are occasional visitors from the heatless periphery of the solar system. Previous works hypothesized that a great majority of OCCs must physically disrupt after one or two passages through the inner solar system, where strong thermal gradients can cause phase transitions or volatile pressure buildup. Here we study the fate of small debris particles produced by OCC disruptions to determine whether the imprints of a hypothetical population of OCC meteoroids can be found in the existing meteor radar data. We find that OCC particles with diameters D < or approx. 10 microns are blown out from the solar system by radiation pressure, while those with D > or approx. 1 mm have a very low Earth-impact probability. The intermediate particle sizes, D approx. 100 microns represent a sweet spot. About 1% of these particles orbitally evolve by Poynting-Robertson drag to reach orbits with semimajor axis a approx. 1 AU. They are expected to produce meteors with radiants near the apex of the Earth s orbital motion. We find that the model distributions of their impact speeds and orbits provide a good match to radar observations of apex meteors, except for the eccentricity distribution, which is more skewed toward e approx. 1 in our model. Finally, we propose an explanation for the long-standing problem in meteor science related to the relative strength of apex and helion/antihelion sources. As we show in detail, the observed trend, with the apex meteors being more prominent in observations of highly sensitive radars, can be related to orbital dynamics of particles released on the long-period orbits.

  17. High-altitude radar meteors observed at Jicamarca Radio Observatory using a multibaseline interferometric technique

    NASA Astrophysics Data System (ADS)

    Gao, Boyi; Mathews, John D.

    2015-10-01

    A new unambiguous, multibaseline interferometric technique was recently employed for meteor observations at Jicamarca Radio Observatory (JRO). These observations largely confirm high-altitude radar meteors (HARMs). The 50 MHz JRO array is arranged in contiguous quarter-arrays (Q) each of which is comprised of 4 × 4 sub-arrays (M), which are referred to as square modules in the Ochs' manual. In these observations the radar transmission was from two quarter-arrays sharing a common diagonal. Signal reception was via three, quarter-array (Q) receivers and three adjacent (M) module receivers all of the same polarization. This arrangement offered the usual Q-Q and M-M interferometric baseline-pairs as well as new Q-M baselines that were rotated ˜6° from the Q-Q and M-M baselines. For relatively high signal-to-noise ratio meteors, this arrangement yields ambiguity resolution to the horizon and confirms the existence of HARM events. We report results from 2014 August 4 to 5 observations that include interesting new HARM events and also suggest the meteoric origin of high-altitude, altitude-extended transient events we named `Dragons' in our earlier report (Gao & Mathews 2015a). We hope to extend this new technique with yet more baselines and higher sensitivity in near future observations.

  18. Kinetic Theory of Meteor Plasma in the Earth's atmosphere: Implications for Radar Head Echo

    NASA Astrophysics Data System (ADS)

    Dimant, Y. S.; Oppenheim, M. M.

    2015-12-01

    Every second millions of tiny meteoroids hit the Earth from space, vast majority too small to be observed visually. However, radars detect the plasma they generate and use the collected data to characterize the incoming meteoroids and the atmosphere in which they disintegrate. This diagnostics requires a detailed quantitative understanding of formation of the meteor plasma and how it interacts with the Earth's atmosphere. Fast-descending meteoroids become detectable to radars after they heat due to collisions with atmospheric molecules sufficiently and start ablating. The ablated material then collides into atmospheric molecules and forms plasma around the meteoroid. Reflection of radar pulses from this plasma produces a localized signal called a head echo often accompanied by a much longer non-specular trail (see the Figure). Using first principles, we have developed a consistent collisional kinetic theory of the near-meteoroid plasma responsible for the radar head echo. This theory produces analytic expressions describing the ion and neutral velocity distributions along with the detailed 3-D spatial structure of the near-meteoroid plasma. These expressions predict a number of unexpected features such as shell-like velocity distributions. This theory shows that the meteoroid plasma develops over a length-scale close to the ion mean free path with a strongly non-Maxwellian velocity distribution. The spatial distribution of the plasma density shows significant deviations from a Gaussian law usually employed in head-echo modeling. This analytical model will serve as a basis for a more accurate quantitative interpretation of radar measurements, estimates of the ionization efficiency, and should help calculate meteoroid and atmosphere parameters from radar head-echo observations. This theory could also help clarify the physical nature of electromagnetic pulses observed during recent meteor showers and associated with the passage of fast-moving meteors through the

  19. Mass distribution of meteoroids obtained by a meteor forward-scatter (MFS) radar method.

    NASA Astrophysics Data System (ADS)

    Cevolani, G.; Gabucci, M. F.

    1996-04-01

    The cumulative distributions of the number vs. duration of echoes belonging to main meteor showers (Lyrids, η-Aquarids, δ-Aquarids, Perseids, Orionids, Leonids, Geminids) and sporadic background were investigated using a forward-scatter (FS) continuous-wave meteor radar link operational during 1992 - 95 over the long baseline Bologna-Lecce in Italy. The trend of the mass distribution of particles in the quoted meteoroid streams was derived, and the values of the mass index s were compared for each meteor population with the steady-state condition. It was found that the mass index s generally increases towards long-duration echoes, but many of the observed meteor streams appear to have unstable populations. The values of the mass index of the sporadic complex are generally higher than the corresponding ones of meteor showers in the range of echo durations 0.1 ≤ T ≤ 10 s. This is a possible consequence of longer-lasting FS signals, indicating a shift of the mass distribution function vs. higher echo durations. Moreover, non-gravitational forces in connection with solar radiation pressure, Poynting-Robertson effect, solar-wind particle streaming, mutual collisions, etc., appear to be responsible for the observed widespread radiants and for unstable populations in the meteoroid streams.

  20. Application of multiple-hypothesis tracking to agile beam radar tracking

    NASA Astrophysics Data System (ADS)

    Popoli, Robert F.; Blackman, Samuel S.; Busch, M. T.

    1996-05-01

    This paper describes methods that have been developed for using multiple hypothesis tracking (MHT) for an agile beam radar in the presence of range gate pull off (RGPO) electronic countermeasures (ECM). The paper shows how the agile beam radar allocation logic can be extended to include uncertainty in target position due to data association uncertainty. It also shows how the MHT track score can be modified to reflect target offset from the commanded radar antenna position and how measured SNR is included in the track score. Results from the second Benchmark tracking study are presented. These results show MHT-based allocation to ge highly efficient. The results also show that the system satisfies stringent track maintenance requirements in the presence of RGPO and coincident target maneuvers.

  1. Agile

    NASA Technical Reports Server (NTRS)

    Trimble, Jay Phillip

    2013-01-01

    This is based on a previous talk on agile development. Methods for delivering software on a short cycle are described, including interactions with the customer, the affect on the team, and how to be more effective, streamlined and efficient.

  2. Assessment of Gravity Wave Momentum Flux Measurement Capabilities by Meteor Radars Having Different Transmitter Power and Antenna Configurations

    NASA Technical Reports Server (NTRS)

    Fritts, D. C.; Janches, D.; Hocking, W. K.; Mitchell, N. J.; Taylor, M. J.

    2011-01-01

    Measurement capabilities of five meteor radars are assessed and compared to determine how well radars having different transmitted power and antenna configurations perform in defining mean winds, tidal amplitudes, and gravity wave (GW) momentum fluxes. The five radars include two new-generation meteor radars on Tierra del Fuego, Argentina (53.8 deg S) and on King George Island in the Antarctic (62.1 deg S) and conventional meteor radars at Socorro, New Mexico (34.1 deg N, 106.9 deg W), Bear Lake Observatory, Utah (approx 41.9 deg N, 111.4 deg W), and Yellowknife, Canada (62.5 deg N, 114.3 deg W). Our assessment employs observed meteor distributions for June of 2009, 2010, or 2011 for each radar and a set of seven test motion fields including various superpositions of mean winds, constant diurnal tides, constant and variable semidiurnal tides, and superposed GWs having various amplitudes, scales, periods, directions of propagation, momentum fluxes, and intermittencies. Radars having higher power and/or antenna patterns yielding higher meteor counts at small zenith angles perform well in defining monthly and daily mean winds, tidal amplitudes, and GW momentum fluxes, though with expected larger uncertainties in the daily estimates. Conventional radars having lower power and a single transmitting antenna are able to describe monthly mean winds and tidal amplitudes reasonably well, especially at altitudes having the highest meteor counts. They also provide qualitative estimates of GW momentum fluxes at the altitudes having the highest meteor counts; however, these estimates are subject to uncertainties of approx 20 to 50% and uncertainties rapidly become excessive at higher and lower altitudes. Estimates of all quantities degrade somewhat for more complex motion fields.

  3. Assessment of gravity wave momentum flux measurement capabilities by meteor radars having different transmitter power and antenna configurations

    NASA Astrophysics Data System (ADS)

    Fritts, D. C.; Janches, D.; Hocking, W. K.; Mitchell, N. J.; Taylor, M. J.

    2012-05-01

    Measurement capabilities of five meteor radars are assessed and compared to determine how well radars having different transmitted power and antenna configurations perform in defining mean winds, tidal amplitudes, and gravity wave (GW) momentum fluxes. The five radars include two new-generation meteor radars on Tierra del Fuego, Argentina (53.8°S) and on King George Island in the Antarctic (62.1°S) and conventional meteor radars at Socorro, New Mexico (34.1°N, 106.9°W), Bear Lake Observatory, Utah (˜41.9°N, 111.4°W), and Yellowknife, Canada (62.5°N, 114.3°W). Our assessment employs observed meteor distributions for June of 2009, 2010, or 2011 for each radar and a set of seven test motion fields including various superpositions of mean winds, constant diurnal tides, constant and variable semidiurnal tides, and superposed GWs having various amplitudes, scales, periods, directions of propagation, momentum fluxes, and intermittencies. Radars having higher power and/or antenna patterns yielding higher meteor counts at small zenith angles perform well in defining monthly and daily mean winds, tidal amplitudes, and GW momentum fluxes, though with expected larger uncertainties in the daily estimates. Conventional radars having lower power and a single transmitting antenna are able to describe monthly mean winds and tidal amplitudes reasonably well, especially at altitudes having the highest meteor counts. They also provide reasonable estimates of GW momentum fluxes at the altitudes having the highest meteor counts; however, these estimates are subject to uncertainties of ˜20 to 50% and uncertainties rapidly become excessive at higher and lower altitudes. Estimates of all quantities degrade somewhat for more complex motion fields.

  4. Discrete exterior calculus for numerical simulation of meteor head-echo radar reflections

    NASA Astrophysics Data System (ADS)

    Räbinä, J.; Mönkölä, S.; Rossi, T.; Penttilä, A.; Markkanen, J.; Muinonen, K.

    2014-07-01

    The meteor head-echo feature has been studied by high-power large-aperture (HPLA) radars since 1960's (see Evans 1965). Based on the observations conducted by the different radar systems and post-processing techniques, there exist several models for the meteor head-echo simulations. One reason for this is the characteristics of the radar system, e.g., in terms of frequency and antenna geometry (see Kero et al. 2012). It is also worth mentioning that there are significant differences in the meteor sizes. According to the observations reported by, e.g., Vertatschitsch et al. (2011) and Wannberg et al. (2011), the head echo can be modeled as overdense scatter from a plasma layer, surrounding the meteor, with a certain density distribution. In these models, the plasmatic object is assumed to be a conducting spherical object, and the electromagnetic phenomenon can be presented by partial differential equations coupling the electric and magnetic fields. The traditional way of solving electromagnetic problems presented in space-time-domain as partial differential equations is to use the finite-difference time-domain method (FDTD; see Dyrud et al. 2008). In this study, we use more generalized finite differences by applying the discrete exterior calculus (DEC) to the numerical simulation of meteor head-echo radar reflections. The properties and calculus of differential forms is provided in a natural way at the discretization stage, and we associate the degrees of freedom of the electric and magnetic fields to the primal and dual mesh structures, respectively. The connection between the primal and dual forms is obtained by the discrete Hodge operator, the quality of which depends on the mesh construction. Our generalized formulation of the DEC for the Maxwell equations (see Pauly and Rossi 2011) works basically on unstructured grids, and it covers both the classical Yee's FDTD scheme and the Bossavit-Kettunen approach (Bossavit and Kettunen 1999). The method has been shown

  5. Experimental Radar Studies of Anisotropic Diffusion of High Altitude Meteor Trails

    NASA Astrophysics Data System (ADS)

    Hocking, W. K.

    2004-12-01

    At altitudes above 93 km in the atmosphere, magnetic and electric fields can affect the modes and rates of non-turbulent diffusion of ionized meteor trails. Anisotropic diffusion is expected. Most theories of anisotropic diffusion, and indeed most experimental studies, have concentrated on the effects of the magnetic field in producing this anisotropy, and different rates of expansion are expected in directions parallel to and perpendicular to the magnetic field lines. In this study, we use interferometric meteor radars to investigate the dependence of the ambipolar diffusion coefficient on viewing direction relative to the magnetic field, and show that the dependence is at best weak when daily averages are used. We then demonstrate that the reason for this effect is that the positions of maximum and minimum diffusion rates varies as a function of time of day, and that daily averaging masks the anisotropy. One possibility to account for the observations is that this strong diurnal variation is a consequence of the electric fields in the upper atmosphere, which are often tidally driven. An alternative possibility is a diurnal cycle in mean meteor entrance speeds. We lean towards the first hypothesis, but both possibilities are discussed. We demonstrate our results with data from several sites, but particularly using the Clovar radar near London, Ontario, Canada.

  6. Recent shower outbursts detected by the Canadian Meteor Orbit Radar (CMOR)

    NASA Astrophysics Data System (ADS)

    Brown, P.

    2016-01-01

    We present recent detections of short-duration shower outbursts as measured by the Canadian Meteor Orbit Radar (CMOR) between 2013-2016. In this interval, CMOR detected two strong shower outbursts unlinked to known showers. These included an outburst of the Kappa Cancrids (KCA - IAU 793) on January 5, 2015 and from the Gamma Lyrids (GLY - IAU 794) on February 7, 2015. Both have an orbit consistent with a Halley-type comet (HTC) or nearly isotropic-comet. Analysis of GLY activity also revealed a previously unreported annual shower, the September Ursae Majorids, (SUR - IAU 795).

  7. Aeronomy report no. 74: The Urbana meteor-radar system; design, development, and first observations

    NASA Technical Reports Server (NTRS)

    Hess, G. C.; Geller, M. A.

    1976-01-01

    The design, development, and first observations of a high power meteor-radar system located near Urbana, Illinois are described. The roughly five-fold increase in usable echo rate compared to other facilities, along with automated digital data processing and interferometry measurement of echo arrival angles, permits unsurpassed observations of tidal structure and shorter period waves. Such observations are discussed. The technique of using echo decay rates to infer density and scale height and the method of inferring wind shear from radial acceleration are examined. An original experiment to test a theory of the Delta-region winter anomaly is presented.

  8. Controlled time integration for the numerical simulation of meteor radar reflections

    NASA Astrophysics Data System (ADS)

    Räbinä, Jukka; Mönkölä, Sanna; Rossi, Tuomo; Markkanen, Johannes; Gritsevich, Maria; Muinonen, Karri

    2016-07-01

    We model meteoroids entering the Earth's atmosphere as objects surrounded by non-magnetized plasma, and consider efficient numerical simulation of radar reflections from meteors in the time domain. Instead of the widely used finite difference time domain method (FDTD), we use more generalized finite differences by applying the discrete exterior calculus (DEC) and non-uniform leapfrog-style time discretization. The computational domain is presented by convex polyhedral elements. The convergence of the time integration is accelerated by the exact controllability method. The numerical experiments show that our code is efficiently parallelized. The DEC approach is compared to the volume integral equation (VIE) method by numerical experiments. The result is that both methods are competitive in modelling non-magnetized plasma scattering. For demonstrating the simulation capabilities of the DEC approach, we present numerical experiments of radar reflections and vary parameters in a wide range.

  9. Meteor radar observations of mesopause region long-period temperature oscillations

    NASA Astrophysics Data System (ADS)

    Jacobi, Ch.; Samtleben, N.; Stober, G.

    2016-09-01

    Meteor radar observations of mesosphere/lower thermosphere (MLT) daily temperatures have been performed at Collm, Germany since August 2004. The data have been analyzed with respect to long-period oscillations at time scales of 2-30 days. The results reveal that oscillations with periods of up to 6 days are more frequently observed during summer, while those with longer periods have larger amplitudes during winter. The oscillations may be considered as the signature of planetary waves. The results are compared with analyses from radar wind measurements. Moreover, the temperature oscillations show considerable year-to-year variability. In particular, amplitudes of the quasi 5-day oscillation have increased during the last decade, and the quasi 10-day oscillations are larger if the equatorial stratospheric winds are eastward.

  10. The frequency-agile radar: A multifunctional approach to remote sensing of the ionosphere

    NASA Astrophysics Data System (ADS)

    Tsunoda, R. T.; Livingston, R. C.; Buonocore, J. J.; McKinley, A. V.

    1995-09-01

    We introduce a new kind of diagnostic sensor that combines multifunctional measurement capabilities for ionospheric research. Multifunctionality is realized through agility in frequency selection over an extended band (1.5 to 50 MHz), system modularity, complete system control by software written in C, and a user-friendly computer interface. This sensor, which we call the frequency-agile radar (FAR), incorporates dual radar channels and an arbitrary waveform synthesizer that allows creative design of sophisticated waveforms as a means of increasing its sensitivity to weak signals while minimizing loss in radar resolution. The sensitivity of the FAR is determined by two sets of power amplifier modules: four 4-kW solid-state broadband amplifiers, and four 30-kW vacuum tube amplifiers. FAR control is by an AT-bus personal computer with on-line processing by a programmable array processor. The FAR does not simply house the separate functions of most radio sensors in use today, it provides convenient and flexible access to those functions as elements to be used in any combination. Some of the first new results obtained with the FAR during recent field campaigns are presented to illustrate its versatility. These include (1) the first detection of anomalous high-frequency (HF) reflections from a barium ion cloud, (2) the first evidence of unexpectedly large drifts and a shear north of the equatorial electrojet, (3) the first HF radar signature of a developing equatorial plasma bubble, and (4) the first measurements by a portable radar of altitude-extended, quasi-periodic backscatter from midlatitude sporadic E. We also mention the potential of the FAR for atmospheric remote sensing.

  11. Combined observations of meteors by image-orthicon television camera and multi-station radar. [to compare ionization with luminosity

    NASA Technical Reports Server (NTRS)

    Cook, A. F.; Forti, G.; Mccrosky, R. E.; Posen, A.; Southworth, R. B.; Williams, J. T.

    1973-01-01

    Observations from multiple sites of a radar network and by television of 29 individual meteors from February 1969 through June 1970 are reported. Only 12 of the meteors did not appear to fragment over all the observed portion of their trajectories. From these 12, the relation for the radar magnitude to the panchromatic absolute magnitude was found in terms of velocity of the meteor. A very tentative fit to the data on the duration of long enduring echoes versus visual absolute magnitude is made. The exponential decay characteristics of the later parts of several of the light curves are pointed out as possible evidence of mutual coalescence of droplets into which the meteoroid has completely broken.

  12. 95 years anniversary of Professor BL Kashcheyev (1920 - 2004) - the well-known Ukrainian researcher of meteors by the radar method

    NASA Astrophysics Data System (ADS)

    Kolomiyets, Svitlana

    2015-08-01

    Meteor astronomy is constantly evolving. We can distinguish several stages in the development of meteor astronomy. One of these steps is the period associated with carrying out the global program called "International Geophysical Year 1957" (IGY1957). Thanks to this program in Ukraine in Kharkiv has been studied meteors using radar techniques. One of the organizers of the IGY 1957 meteor program execution in Ukraine (and in the former Soviet Union) was prof. BL Kashcheyev (1920-2004). At the IAU GA in 1958 prof. BL Kashcheyev made the report on the meteor radar studies in Kharkiv. These research were considered by the IAU Commission 22 as the best in the world. The name of Professor BL Kashcheyev related to the creation of the Kharkiv meteor radar system and the long series of meteor observations, creating the database of 250 thousand orbits of faint meteors (12^ M), carrying out the variety of meteor projects (including the GLOBMET). In 2004 the Kharkiv meteor radar complex was given the status of national heritage of Ukraine. In 2007, the organizers of the program "International Heliophisic Year 2007" (IHY2007) remarked the BL Kashcheyev contribution to the IGY 1957 (the certificate and the pin "The IGY1957 Gold ").

  13. Interhemispheric structure and variability of the 5-day planetary wave from meteor radar wind measurements

    NASA Astrophysics Data System (ADS)

    Iimura, H.; Fritts, D. C.; Janches, D.; Singer, W.; Mitchell, N. J.

    2015-11-01

    A study of the quasi-5-day wave (5DW) was performed using meteor radars at conjugate latitudes in the Northern and Southern hemispheres. These radars are located at Esrange, Sweden (68° N) and Juliusruh, Germany (55° N) in the Northern Hemisphere, and at Tierra del Fuego, Argentina (54° S) and Rothera Station, Antarctica (68° S) in the Southern Hemisphere. The analysis was performed using data collected during simultaneous measurements by the four radars from June 2010 to December 2012 at altitudes from 84 to 96 km. The 5DW was found to exhibit significant short-term, seasonal, and interannual variability at all sites. Typical events had planetary wave periods that ranged between 4 and 7 days, durations of only a few cycles, and infrequent strongly peaked variances and covariances. Winds exhibited rotary structures that varied strongly among sites and between events, and maximum amplitudes up to ~ 20 m s-1. Mean horizontal velocity covariances tended to be largely negative at all sites throughout the interval studied.

  14. Simultaneous mesospheric wind measurements near South Pole by optical and meteor radar methods

    NASA Astrophysics Data System (ADS)

    Hernandez, G.; Forbes, J. M.; Smith, R. W.; Portnyagin, Y.; Booth, J. F.; Makarov, N.

    Simultaneous and co-located measurements of mesospheric winds near South Pole, by high-resolution optical and meteor radar methods, show that these two methods determine very similar motions at slightly different heights of observation. The measured atmospheric motions by the two techniques show that a) The mean wind during 12 days in June, 1995 was found to have a 7 m/s amplitude flowing towards the 5°E longitude direction. The latter direction is different from the 30E° direction found earlier during August 1991 and 1992. b) The observed dominant oscillations in the wind at both heights of observation are those of zonal wavenumber one character. Westward phase propagation was determined for the observed short-period (∼0 hours) oscillations and eastward phase propagation for the longer-period (∼3 days) oscillations, respectively. Because of the neighboring heights of observation by the optical and meteor radar methods, the in situ vertical wavelengths of propagation of the observed waves have been determined to be greater than 100 km for the 10-hr oscillations and near 65 km for the longer period oscillations. With this new information we are able to independently establish the earlier assignment of the nearly 10-hr oscillations as the different meridional modes of a zonal wavenumber one Lamb wave. The determined vertical wavelength and eastward phase progression of the longer periodicity waves indicate these oscillations are likely to be the gravest inertio-gravity wave, which has the appropriate equivalent depths at these periods of oscillation. The simultaneous absence of statistically significant kinetic temperature and optical-tracer emission rate oscillations at the frequencies corresponding to the wind motions, provides independent support to the earlier deductions on the ability of the atmosphere near the rotational poles to support only certain zonal character oscillations.

  15. A 13-year radar study of the η-Aquariid meteor shower

    NASA Astrophysics Data System (ADS)

    Campbell-Brown, M.; Brown, P. G.

    2015-02-01

    We measure the activity and orbital characteristics of the η-Aquariid meteor shower appropriate to meteoroids of 200 μm size (mass ≈ 5-10 μg) based on ˜4 × 104 stream orbits measured by the Canadian Meteor Orbit Radar during the years 2002-2014. Significant activity from the stream is found to last from April 25-May 21 (λ⊙ = 35°-60°) with the shower detectable approximately one week on either side of these dates just above the median background. The radiant at peak activity (λ⊙ = 45.5°) is located at αg = 337.8°, δg = -0.6° and shows a consistent drift of Δαg = +0.69°, Δδg = +0.60°. The velocity of the stream throughout its active period remains within ≈1 km s-1 of Vg = 64.3 km s-1 found at the peak; however, there are indications this is an underestimate due to undercorrection for stream meteoroids having larger than average deceleration. The activity profile shows no mass dependence between μg to mg sizes, but a clear asymmetry with the slope of the ascending branch having B+ = 0.135 ± 0.003 and the descending branch B- = 0.078 ± 0.003. The average yearly equivalent radar-measured peak Zenithal Hourly Rate (ZHR) is 50-80 from 2002-2014, with outbursts in 2004 and 2013 exceeding ZHRs of 100. The mass index shows a minimum at the time of the flux maximum with 1.8 ≤ s ≤ 1.9.

  16. A meteoroid stream survey using the Canadian Meteor Orbit Radar. I. Methodology and radiant catalogue

    NASA Astrophysics Data System (ADS)

    Brown, P.; Weryk, R. J.; Wong, D. K.; Jones, J.

    2008-05-01

    Using a meteor orbit radar, a total of more than 2.5 million meteoroids with masses ˜10 -7 kg have had orbits measured in the interval 2002-2006. From these data, a total of 45 meteoroid streams have been identified using a wavelet transform approach to isolate enhancements in radiant density in geocentric coordinates. Of the recorded streams, 12 are previously unreported or unrecognized. The survey finds >90% of all meteoroids at this size range are part of the sporadic meteoroid background. A large fraction of the radar detected streams have q<0.15 AU suggestive of a strong contribution from sungrazing comets to the meteoroid stream population currently intersecting the Earth. We find a remarkably long period of activity for the Taurid shower (almost half the year as a clearly definable radiant) and several streams notable for a high proportion of small meteoroids only, among these a strong new shower in January at the time of the Quadrantids (January Leonids). A new shower (Epsilon Perseids) has also been identified with orbital elements almost identical to Comet 96P/Machholz.

  17. Vertical winds and momentum fluxes due to equatorial planetary scale waves using all-sky meteor radar over Brazilian region

    NASA Astrophysics Data System (ADS)

    Egito, F.; Andrioli, V. F.; Batista, P. P.

    2016-11-01

    In the equatorial region planetary scale waves play an important role transporting significant amount of energy and momentum through atmosphere. Quantifying the momentum transported by these waves and its effects on the mean flow is rather important. Direct estimates of the momentum flux transported by waves require horizontal and vertical wind measurements. Ground-based meteor radars have provided continuous and reliable measurements of the horizontal wind components in the Mesosphere and Lower Thermosphere (MLT) region and have contributed to improve our knowledge of the dynamics of this region. However, instrumental limitations hinder its use for measuring vertical winds and momentum fluxes. On the other hand, according to Babu et al (2012), all- sky meteor radars are able to infer tridimensional winds when using a large number of meteor echoes centered at the meteor ablation peak. Following this approach, we have used measurements performed by a Meteor Radar installed at São João do Cariri, Brazil (7.4°S; 36.5°W) in order to measure vertical winds and calculate the momentum flux transported by equatorial planetary scale waves. In order to evaluate the accuracy of vertical wind values we have performed several tests based on a simple model considering real meteor distributions and theoretical equations for the MLT winds motion. From our tests, we inferred that Brazilian meteor radar data can be used for this purpose with an accuracy of ~ 1.8 m/s. The results show that the vertical wind presents magnitudes of a few meters per second and occasionally reaches magnitudes around 10 m/s. Below 92 km the vertical wind is predominantly upward during the whole year and above exhibits a semi-annual oscillation with downward phase during the equinoxes. Variations associated to planetary scale waves in the vertical wind are also observed and some of them appear simultaneously in the zonal and meridional wind as well. Largest wave induced amplitudes in the vertical wind

  18. The Canadian Meteor Orbit Radar II: A new Facility for Measurement of the Dust Environment in near-Earth space

    NASA Astrophysics Data System (ADS)

    Brown, Peter G.; Weryk, R. J.; Wong, D. K.; Campbell-Brown, M. D.

    2012-10-01

    The Canadian Meteor Orbit Radar (CMOR) is a backscatter, multi-station meteor radar operating at 29.85 MHz. CMOR has been in operation as a three station system since 2001, but a major upgrade in 2009 has expanded the system to six stations and doubled the transmit power to 15 kW; the new facility is termed CMOR II. CMOR II measures 5000 individual orbits per day of meteoroids with masses 10-8 kg. These large number statistics permit near real-time identification of as many as a dozen significant daily meteor showers, through application of a 3D wavelet transform. As individual meteor echoes are detected at up to six stations, CMOR II is able to measure electron line density profiles and decelerations for select events. This permits estimation of meteoroid bulk density through comparison with entry models for particles as small 100 μm. For events with more than four station detections, errors in radiant and speed are comparable to similar measurements made with video systems. Making use of multiple, independent techniques for speed measurements, including time-of-flight, Fresnel amplitude and Fresnel phase fitting, it is possible to estimate speed accuracy for individual events. Monte Carlo modeling of individual echoes allow a separate estimate for uncertainty in both speed and radiant measurement. Here we present initial results from CMOR II measurements of major meteor showers including the 2012 Daytime Arietids and South Delta Aquariid streams. Detections of several unusual meteor shower outbursts with CMOR II and verification of previously reported weak showers will also be shown. We will demonstrate the capacity of CMOR II for individual meteoroid physical characterization by using measured trajectory, speed, deceleration and electron line density measurements combined with entry model fits to estimate meteoroid parameters. Funding from the NASA Meteoroid Environment Office through cooperative agreement NNX11AB76A is gratefully acknowledged.

  19. Observations of the new Camelopardalids meteor shower using a 38.9 MHz radar at Mohe, China

    NASA Astrophysics Data System (ADS)

    Younger, J. P.; Reid, I. M.; Li, G.; Ning, B.; Hu, L.

    2015-06-01

    The Camelopardalids meteor shower was predicted to occur for the first time on 24 May 2014, based on optical observations of the comet 209P/LINEAR. Using a 38.9 MHz meteor radar located at Mohe, China, we were able to detect approximately 590 shower meteors originating from an average pre-infall radiant of R.A. = 129.1° ± 9.8°, declination = 79.4° ± 1.6° (J2000) with a geocentric velocity of 16.0 ± 1.6 km s-1. Measurements of the shower duration, direction, velocity, and individual meteor detection heights facilitated a detailed analysis of the parent debris stream. Orbital parameters were calculated including a semi-major axis of 2.86 AU, eccentricity of 0.659, and inclination of 21.1°. Combining orbital parameters with the shower activity duration FWHM of 5.09 h, it was found that the stream has a FWHM of at least 211,000 km at 1 AU, as measured perpendicular to the direction of orbital motion. A comparison of shower meteor detection heights and diffusion coefficient estimates with the sporadic background is consistent the prediction of Ye and Wiegert (Ye, Q., Wiegert, P. [2014]. Mon. Not. R. Astron. Soc. 437, 3283-3287) that Camelopardalid meteoroids are biased towards larger sizes or that Cameloppardalid meteoroids are less fragile than sporadic background meteoroids.

  20. Reconfigurable microwave photonic in-phase and quadrature detector for frequency agile radar.

    PubMed

    Emami, Hossein; Sarkhosh, Niusha

    2014-06-01

    A microwave photonic in-phase and quadrature detector is conceived and practically demonstrated. The detector has the ability to become electronically reconfigured to operate at any frequency over a wide range. This makes it an excellent candidate for frequency agile radars and other electronic warfare systems based on frequency hopping. The detector exhibits a very low amplitude and phase imbalance, which removes the need for any imbalance compensation technique. The system is designed based on the transversal filtering concept and reconfigurability is achieved via wavelength control in a dispersive fiber. The system operation was demonstrated over a frequency range of 3.5-35 GHz, with a maximum of -32 dB amplitude imbalance.

  1. The history of meteors and meteor showers

    NASA Astrophysics Data System (ADS)

    Hughes, David W.

    The history of meteors and meteor showers can effectively start with the work of Edmond Halley who overcome the Aristotelean view of meteors as being an upper atmospheric phenomenon and introduced their extraterrestrial nature. Halley also estimated their height and velocity. The observations of the Leonids in 1799, 1833 and 1866 established meteoroids as cometary debris. Two red herrings were caught — fixed radiants and hyperbolic velocities. But the 1890 to 1950 period with two-station meteor photography, meteor spectroscopy and the radar detection of meteors saw the subject well established.

  2. The Daytime Craterids, a radar-detected meteor shower outburst from hyperbolic comet C/2007 W1 (Boattini)

    NASA Astrophysics Data System (ADS)

    Wiegert, P. A.; Brown, P. G.; Weryk, R. J.; Wong, D. K.

    2011-06-01

    We report a new daytime meteor shower detected with the Canadian Meteor Orbit Radar (CMOR). This shower has a radiant in the southern constellation Crater. The Daytime Craterid shower was observed in 2003 and 2008 but not in any of the other years in the 2002-09 interval. The strength of this shower in the years observed is equivalent to a daily averaged zenithal hourly rate (ZHR) over 30, with a peak ZHR likely much higher at the time of the outburst. The orbital elements of the shower closely match those of Comet C/2007 W1 (Boattini), which passed perihelion in 2007. The orbit of C/2007 W1 is nominally hyperbolic orbit making this the first meteor shower detected from a clearly unbound comet. The 2003 outburst of the Daytime Craterid shower indicates that this comet must have recently been transferred to an unbound orbit from a bound one, likely through a close encounter with a giant planet. As a result we conclude that this shower provides us with one of the few examples of showers originating from the population of nearly isotropic comets. The stream is difficult to model owing to its proximity to the orbits of Jupiter, Saturn and the Earth. However, the intermittent nature of the shower can be largely understood from numerical simulations. No outbursts of similar strength are expected in the next decade, with the possible exception of 2015.

  3. Characteristics of Meteor Echoes and Preliminary Winds Collected With a Narrow-Beam Radar at Piura, Peru

    NASA Astrophysics Data System (ADS)

    Lau, E. M.; Avery, S. K.; Avery, J. P.

    2002-12-01

    During the mid 1990's a MEDAC system was attached to the VHF wind profiler located in Piura, Peru to detect and collect meteor echoes and provide measurements of winds in the mesosphere-lower thermosphere. The collected data were different from those of similar systems operating at mid-latitudes and other equatorial sites. In particular, the echo rate was relatively low, the echoes were highly aspect sensitive, many of the meteor echoes were relatively weak suggesting the possibility that they were seen through a sidelobe instead of the main lobe of the antenna, and a great deal of activity was observed at nighttime when E-region echoes were also observed. A series of experiments have been designed to better understand the system and the resulting wind measurements. The first experiment was designed to increase the sensitivity of the radar and was conducted during one week in July 2002. Two transmitters were used instead of the single transmitter that normally feeds the transmit antenna on the wind profiler. Data was collected using three different systems: the wind profiler's own acquisition system, the MEDAC system, and a mode in which all data was collected and saved to the hard drive. This poster presents the results of the aforementioned experiment, compares the results provided by each data collection system, outlines the main features of the meteor echoes seen at Piura, and discusses the preliminary wind measurements.

  4. The analyses of destruction of the meteoric trail on radar observations.

    NASA Astrophysics Data System (ADS)

    Karpov, A.; Tereshin, S.; Abrosimov, J.

    It is known, that ambipolar diffusion defines a destruction of an ionic-electronic trail of underdense type. At the same time attempts of an explanation of destruction of overdense trail by only ambipolar diffusion give large deviations of definition of duration of the meteoric trail. Reduction of duration of existence of the meteoric trail was explained by influence of change of parameter s in distribution of meteoric bodies on weights; influence of effects recombination; to adhere of electrons to the neutral molecules, atoms and turbulent diffusion. The analysis of works of this problem gives, that researchers do not have the good explanation of processes of destruction of the meteoric trail. In this work we try to define the most important processes of destruction of the overdense meteoric trail and to construct model of destruction of an meteoric trail. The analysis of rate of reactions shows, that procesess of the recombination with electronic stabilization, dissociative recombination, two-step process with participation of atmospheric ozone also influence on reduction of concentration of electronic in trail. We constructed models of distributions of duration of radio echo using only one mechanism and combination of all mechanism. Now we plan experimental observations for distinguish of influence of each of mechanisms. This work was funded by the Russian Foundation for Fundamental Research (Project ? 00-02-16845)

  5. Meteor stream survey in the southern hemisphere using SAAMER

    NASA Astrophysics Data System (ADS)

    Janches, D.; da Silva, D.; Pifko, S.; Hormaechea, J.; Hocking, W.; Brunini, C.; Close, S.; Fritts, D.

    2014-07-01

    We present in this manuscript two meteor shower surveys in the Southern Hemisphere utilizing the Southern Argentina Agile Meteor Radar (SAAMER). SAAMER, which operates at the southern most region of South America, is a new generation SKiYMET system designed with significant differences from typical meteor radars including high transmitted power and an 8-antenna transmitting array enabling large detected rates at low zenith angles. For the first survey, we applied the statistical methodology developed by Jones and Jones (2006) to the data collected each day during 4 years and compiled the results into 1 composite representative year at 1-degree resolution in Solar Longitude. We then search for enhancements in the activity, which last for at least 3 days and evolve temporally as is expected for a meteor shower. Using this methodology, we have identified in our data 32 shower radiants, two of which were not part of the IAU commission 22 meteor shower working list (Janches et al., 2014). Recently, SAAMER's capabilities were enhanced by adding two remote stations to receive meteor forward scatter signals from meteor trails and thus enable the determination of meteoroid orbital parameters. SAAMER started recording orbits in January 2012. We also present a 1-year survey using a wavelet-transform approach (Galligan and Baggaley, 2002ab; Brown et al., 2008) of this new orbital dataset to isolate enhancements in radiant density in geocentric coordinates resulting in not only radiant information but shower orbital properties.

  6. Intraseasonal oscillations of the zonal wind near the mesopause observed with medium-frequency and meteor radars in the tropics

    NASA Astrophysics Data System (ADS)

    Isoda, Fusako; Tsuda, Toshitaka; Nakamura, Takuji; Vincent, R. A.; Reid, I. M.; Achmad, Effendy; Sadewo, Adi; Nuryanto, Agus

    2004-11-01

    We studied the behavior of intraseasonal oscillations (ISO) of the zonal wind velocity in the equatorial mesosphere and lower thermosphere (MLT) using simultaneous observations during 500 days from 1 January 1996 with a meteor radar at Jakarta (6°S, 107°E) and two medium-frequency radars at Pontianak (0°N, 109°E) and Christmas Island (2°N, 157°W). Cross-correlation analysis of the ISO at 88 km indicated that the phase difference of the ISO between Pontianak and Christmas Island is, on average, small in spite of the longitudinal difference of ˜90°. Therefore the ISO in the equatorial MLT region seems to be a variation of zonal mean flow. At Jakarta the amplitude of the ISO of the zonal wind at 88 km was somewhat smaller than that observed at the other two equatorial sites. The peak of the ISO amplitude appears at ˜88 km at both Pontianak and Christmas Island, but the peak seemed to be slightly lower at Jakarta. We also investigated long-term variation of the ISO of the zonal wind at 84 km using Jakarta meteor radar data observed from January 1993 to October 1999. Biennial variations are dominant in the ISO amplitude of the mesospheric zonal winds and the zonal amplitude variations of the diurnal tide. A relation between the ISO of the zonal wind and tidal amplitude is suggested. However, gravity wave activity in the MLT region did not correlate with the ISO in the zonal wind. We employed the outgoing longwave radiation (OLR) in the tropical troposphere as an index for excitation intensity of the atmospheric waves. The long-term variations of the ISO components in the OLR over the western Pacific were characterized by the tropospheric biennial oscillations, which seems to correlate with the ISO of the mean zonal winds and diurnal tides in the mesosphere.

  7. First results from the 2009-2010 MU radar head echo observation programme for sporadic and shower meteors: the Orionids 2009

    NASA Astrophysics Data System (ADS)

    Kero, J.; Szasz, C.; Nakamura, T.; Meisel, D. D.; Ueda, M.; Fujiwara, Y.; Terasawa, T.; Miyamoto, H.; Nishimura, K.

    2011-10-01

    The aim of this paper is to demonstrate the capabilities of a new automated analysis scheme developed for meteor head echo observations by the Shigaraki middle and upper atmosphere (MU) radar in Japan (?N, ?E). Our analysis procedure computes meteoroid range, velocity and deceleration as functions of time with unprecedented accuracy and precision. This is crucial for estimations of meteoroid mass and orbital parameters, as well as investigations into meteoroid-atmosphere interaction processes. We collected an extensive set of data (>500 h) between 2009 June and 2010 December. Here, we present initial results from data taken in 2009 October 19-21. More than 600 of about 10 000 head echoes recorded during 33 h were associated with the 1P/Halley dust of the Orionid meteor shower. These meteors constitute a very clear enhancement of meteor radiants centred around right ascension α=? and declination δ=?. Their estimated atmospheric entry velocity of 66.9 km s-1 is in good agreement with 1P/Halley dust ejected in the year 1266 BC, which, according to simulations, crossed Earth's orbit at the time of our observation. The Orionid activity within the MU radar beam reached about 50 h-1 during radiant culmination. The flux of sporadic meteors in the MU radar data, coming primarily from the direction of the Earth's apex, peaked at about 700 h-1 during the same observations.

  8. Relation between meteor head echo mass-velocity selection effects, shower mass distribution indices, and mass threshold of the MU radar

    NASA Astrophysics Data System (ADS)

    Kero, Johan

    2014-01-01

    Observations are described that led to a study of the relationship between the head echo mass-velocity selection effect, the mass distribution indices of the Geminid and Orionid meteor showers, and the mass threshold of the MU radar, published by Kero et al. (2013).

  9. Analysis of Diurnal, Planetary and Mean Wind Activity using TIMED, MF and Meteor Radar Winds

    NASA Technical Reports Server (NTRS)

    Lieberman, Ruth S.; Riggin, Dennis R.

    2003-01-01

    The goals of this research are: 1) To validate TIMED Doppler Interferometer (TIDI) winds using ground-based MF and meteor winds; and 2) To examine short-term (i. e., day-to-day and week-to-week) variability of the diurnal tide. This objective was to have originally been met using comparisons of short-term diurnal tidal determinations from ground-based (GB) winds with planetary-scale diurnal nonmigrating tidal definitions from TIDI winds.

  10. Radar detectability studies of slow and small Zodiacal Dust Cloud Particles: I. The case of Arecibo 430 MHz meteor head echo observations

    PubMed Central

    Janches, D.; Plane, J.M.C.; Nesvorný, D.; Feng, W.; Vokrouhlický, D.; Nicolls, M.J.

    2016-01-01

    Recent model development of the Zodiacal Dust Cloud (ZDC) model (Nesvorný et al. 2010, 2011b) argue that the incoming flux of meteoric material into the Earth’s upper atmosphere is mostly undetected by radars because they cannot detect small extraterrestrial particles entering the atmosphere at low velocities due to the relatively small production of electrons. In this paper we present a new methodology utilizing meteor head echo radar observations that aims to constrain the ZDC physical model by ground-based measurements. In particular, for this work, we focus on Arecibo 430 MHz observations since this is the most sensitive radar utilized for this type of observations to date. For this, we integrate and employ existing comprehensive models of meteoroid ablation, ionization and radar detection to enable accurate interpretation of radar observations and show that reasonable agreement in the hourly rates is found between model predictions and Arecibo observations when: 1) we invoke the lower limit of the model predicted flux (~16 t/d) and 2) we estimate the ionization probability of ablating metal atoms using laboratory measurements of the ionization cross sections of high speed metal atom beams, resulting in values up to two orders of magnitude lower than the extensively utilized figure reported by Jones (1997) for low speeds meteors. However, even at this lower limit the model over predicts the slow portion of the Arecibo radial velocity distributions by a factor of 3, suggesting the model requires some revision. PMID:27642186

  11. Radar Detectability Studies of Slow and Small Zodiacal Dust Cloud Particles: I. The Case of Arecibo 430 MHz Meteor Head Echo Observations

    NASA Technical Reports Server (NTRS)

    Janches, D.; Plane, J. M. C.; Nesvorny, D.; Feng, W.; Vokrouhlicky, D.; Nicolls, M. J.

    2014-01-01

    Recent model development of the Zodiacal Dust Cloud (ZDC) model (Nesvorny et al. 2010, 2011b) argue that the incoming flux of meteoric material into the Earth's upper atmosphere is mostly undetected by radars because they cannot detect small extraterrestrial particles entering the atmosphere at low velocities due to the relatively small production of electrons. In this paper we present a new methodology utilizing meteor head echo radar observations that aims to constrain the ZDC physical model by ground-based measurements. In particular, for this work, we focus on Arecibo 430 MHz observations since this is the most sensitive radar utilized for this type of observations to date. For this, we integrate and employ existing comprehensive models of meteoroid ablation, ionization and radar detection to enable accurate interpretation of radar observations and show that reasonable agreement in the hourly rates is found between model predictions and Arecibo observations when: 1) we invoke the lower limit of the model predicted flux (approximately 16 t/d) and 2) we estimate the ionization probability of ablating metal atoms using laboratory measurements of the ionization cross sections of high speed metal atom beams, resulting in values up to two orders of magnitude lower than the extensively utilized figure reported by Jones (1997) for low speeds meteors. However, even at this lower limit the model over predicts the slow portion of the Arecibo radial velocity distributions by a factor of 3, suggesting the model requires some revision.

  12. Radar detectability studies of slow and small Zodiacal Dust Cloud Particles: I. The case of Arecibo 430 MHz meteor head echo observations

    PubMed Central

    Janches, D.; Plane, J.M.C.; Nesvorný, D.; Feng, W.; Vokrouhlický, D.; Nicolls, M.J.

    2016-01-01

    Recent model development of the Zodiacal Dust Cloud (ZDC) model (Nesvorný et al. 2010, 2011b) argue that the incoming flux of meteoric material into the Earth’s upper atmosphere is mostly undetected by radars because they cannot detect small extraterrestrial particles entering the atmosphere at low velocities due to the relatively small production of electrons. In this paper we present a new methodology utilizing meteor head echo radar observations that aims to constrain the ZDC physical model by ground-based measurements. In particular, for this work, we focus on Arecibo 430 MHz observations since this is the most sensitive radar utilized for this type of observations to date. For this, we integrate and employ existing comprehensive models of meteoroid ablation, ionization and radar detection to enable accurate interpretation of radar observations and show that reasonable agreement in the hourly rates is found between model predictions and Arecibo observations when: 1) we invoke the lower limit of the model predicted flux (~16 t/d) and 2) we estimate the ionization probability of ablating metal atoms using laboratory measurements of the ionization cross sections of high speed metal atom beams, resulting in values up to two orders of magnitude lower than the extensively utilized figure reported by Jones (1997) for low speeds meteors. However, even at this lower limit the model over predicts the slow portion of the Arecibo radial velocity distributions by a factor of 3, suggesting the model requires some revision.

  13. Characterization of Leonid meteor head echo data collected using the VHF-UHF Advanced Research Projects Agency Long-Range Tracking and Instrumentation Radar (ALTAIR)

    NASA Astrophysics Data System (ADS)

    Close, S.; Hunt, S. M.; McKeen, F. M.; Minardi, M. J.

    2002-02-01

    The Leonid meteor shower, which was predicted to hit storm-like activity on 17 November 1998, was observed using radar and optical sensors at the Kwajalein Missile Range in order to study potential threats to orbiting spacecraft. Meteor head echo data were collected during the predicted peak of the ``storm'' primarily using the Advanced Research Projects Agency Long-Range Tracking and Instrumentation Radar (ALTAIR). ALTAIR is a dual-frequency radar at VHF (160 MHz) and UHF (422 MHz) that is uniquely suited for detecting meteor head echoes due to high sensitivity, precise calibration, and the ability to record radar data at a high rate (Gb/min). ALTAIR transmits right-circular (RC) polarized energy and records left-circular (LC) sum, RC sum, LC azimuth angle difference, and LC elevation angle difference channels; these four measurements facilitate the determination of three-dimensional target position and velocity as a function of radar cross section and time. During the predicted peak of the storm, ALTAIR detected 734 VHF head echoes in 29 min of data and 472 UHF head echoes in 17 min of data, as well as numerous specular and nonspecular ionization trails. This paper contains analysis on the head echo data, including dual-frequency statistics and the variability of head echo decelerations. We also include results from the analysis of the radius-density parameter, which shows a strong correlation with deceleration.

  14. Radar detectability studies of slow and small Zodiacal Dust Cloud Particles: I. The case of Arecibo 430 MHz meteor head echo observations.

    PubMed

    Janches, D; Plane, J M C; Nesvorný, D; Feng, W; Vokrouhlický, D; Nicolls, M J

    2014-11-20

    Recent model development of the Zodiacal Dust Cloud (ZDC) model (Nesvorný et al. 2010, 2011b) argue that the incoming flux of meteoric material into the Earth's upper atmosphere is mostly undetected by radars because they cannot detect small extraterrestrial particles entering the atmosphere at low velocities due to the relatively small production of electrons. In this paper we present a new methodology utilizing meteor head echo radar observations that aims to constrain the ZDC physical model by ground-based measurements. In particular, for this work, we focus on Arecibo 430 MHz observations since this is the most sensitive radar utilized for this type of observations to date. For this, we integrate and employ existing comprehensive models of meteoroid ablation, ionization and radar detection to enable accurate interpretation of radar observations and show that reasonable agreement in the hourly rates is found between model predictions and Arecibo observations when: 1) we invoke the lower limit of the model predicted flux (~16 t/d) and 2) we estimate the ionization probability of ablating metal atoms using laboratory measurements of the ionization cross sections of high speed metal atom beams, resulting in values up to two orders of magnitude lower than the extensively utilized figure reported by Jones (1997) for low speeds meteors. However, even at this lower limit the model over predicts the slow portion of the Arecibo radial velocity distributions by a factor of 3, suggesting the model requires some revision.

  15. Radar detectability studies of slow and small zodiacal dust cloud particles. I. The case of Arecibo 430 MHz meteor head echo observations

    SciTech Connect

    Janches, D.; Nesvorný, D.; Vokrouhlický, D.; Nicolls, M. J. E-mail: j.m.c.plane@leeds.ac.uk E-mail: davidn@boulder.swri.edu E-mail: Michael.Nicolls@sri.com

    2014-11-20

    Recent model development of the Zodiacal Dust Cloud (ZDC) argues that the incoming flux of meteoric material into the Earth's upper atmosphere is mostly undetected by radars because they cannot detect small extraterrestrial particles entering the atmosphere at low velocities due to the relatively small production of electrons. In this paper, we present a new methodology utilizing meteor head echo radar observations that aims to constrain the ZDC physical model by ground-based measurements. In particular, for this work, we focus on Arecibo 430 MHz observations since this is the most sensitive radar utilized for this type of observations to date. For this, we integrate and employ existing comprehensive models of meteoroid ablation, ionization, and radar detection to enable accurate interpretation of radar observations and show that reasonable agreement in the hourly rates is found between model predictions and Arecibo observations when (1) we invoke the lower limit of the model predicted flux (∼16 t d{sup –1}) and (2) we estimate the ionization probability of ablating metal atoms using laboratory measurements of the ionization cross sections of high-speed metal atom beams, resulting in values up to two orders of magnitude lower than the extensively utilized figure reported by Jones for low-speed meteors. However, even at this lower limit, the model overpredicts the slow portion of the Arecibo radial velocity distributions by a factor of three, suggesting that the model requires some revision.

  16. Searching for dormant comets in the NEO region using data from the Canadian Meteor Orbit Radar

    NASA Astrophysics Data System (ADS)

    Ye, Quan-Zhi; Brown, Peter

    2015-11-01

    Dormant comets (DCs) are objects that appear asteroidal but have cometary origins. Earth-approaching DCs may produce dust during their final active stages which potentially are detectable as weak meteor showers at the Earth. However, identifying DCs is difficult as they are observationally indistinguishable from asteroids. Past asteroid-stream searches have produced some possible linkages between asteroids and meteor showers, the most notable being the Geminids and 3200 (Phaethon) and the Quadrantids and (196256) 2003 EH1. However, a comprehensive survey to look for all possible weak streams from recent DC activity, including dynamical formation and evolution of early dust trails has yet to be performed. Here we report on the progress of a DC meteoroid stream survey whereby we have identified all DC candidates whose orbits are such that recent (last several hundred years) dust release would be currently detectable at the Earth. We have simulated the evolution of dust trails for all candidate DC-stream objects and generate predictions for the characteristics of the associated DC shower at Earth. We then perform a cued survey for such streams among the 15 mega meteoroid orbits measured by CMOR since 2002, using a wavelet-based search algorithm with probe sizes tuned to the expected shower characteristics. The search is focused on ~300 Earth-approaching asteroids that have dynamical characteristics of comets (or asteroids in cometary orbits, ACOs). For some cases we will also discuss the connection between the meteor data and astrophysical observations of the parent body itself.

  17. Meteoric Head Echoes

    NASA Astrophysics Data System (ADS)

    Hajduk, A.; Galád, A.

    1995-01-01

    Results of the analysis of 3261 radar meteor head echoes observed during the Orionid and Lyrid periods by the high-power radar of the Springhill Meteor Observatory are given. Dependence of the occurence of head echoes on the geometrical factors and physical properties of the meteoroids has been studied. Increas of the head echo rates with the elevation of the shower radiant and with the velocity of meteoroids has been observed.

  18. Meteor Showers.

    ERIC Educational Resources Information Center

    Kronk, Gary W.

    1988-01-01

    Described are the history, formation, and observing techniques of meteors and comets. Provided are several pictures, diagrams, meteor organizations and publications, and meteor shower observation tables. (YP)

  19. Meteor Researches at Khnure

    NASA Astrophysics Data System (ADS)

    Kolomiyets, Svitlana V.; Voloshchuk, Yuri I.; Kashcheyev, Boris L.; Slipchenko, Nikolay I.

    The Scientific Educational Center of Radioengineering of the Kharkiv National University of Radioelectronics (KHNURE: ) is one of the oldest radar meteor centers which was founded by B. L. Kashcheyev in 1958. The first automatic meteor radar system in Ukraine “MARS” is connected with our University. There are long-term observational series of meteor rates and orbital data in the Center. Fields of the KHNURE researches are: a structure of meteor showers a determination of meteoroid orbits an influx of cosmic rubbish in the Earth atmosphere search of parental bodies of meteoroids a statistic analysis of measurement results of radiometeors an estimation of errors of meteor radar measurements a search for real hyperbolic orbits and interstellar meteoroids. KHNURE disposes a unique electronic orbital catalogue. This catalogue contains the primary information velocities radiants and orbits of nearly 250000 radiometeoroids with masses from 0.001 to 0.000001 g. The “MARS” registered these data during observations of 1972 1978. From these data 5160 meteor streams are singled out. New classification of streams is made in view of their structure. The study of meteor stream orbits from the KHNURE data bank allow to predict orbits of a big number of undiscovered “dangerous” NEOs

  20. Meteor researches at KHNURE

    NASA Astrophysics Data System (ADS)

    Kolomiyets, Svitlana V.; Voloshchuk, Yuri I.; Kashcheyev, Boris L.; Slipchenko, Nikolay I.

    2005-01-01

    The Scientific Educational Center of Radioengineering of the Kharkiv National University of Radioelectronics (KHNURE: ) is one of the oldest radar meteor centers which was founded by B. L. Kashcheyev in 1958. The first automatic meteor radar system in Ukraine “MARS” is connected with our University. There are long-term observational series of meteor rates and orbital data in the Center. Fields of the KHNURE researches are: a structure of meteor showers a determination of meteoroid orbits an influx of cosmic rubbish in the Earth atmosphere search of parental bodies of meteoroids a statistic analysis of measurement results of radiometeors an estimation of errors of meteor radar measurements a search for real hyperbolic orbits and interstellar meteoroids. KHNURE disposes a unique electronic orbital catalogue. This catalogue contains the primary information velocities radiants and orbits of nearly 250000 radiometeoroids with masses from 0.001 to 0.000001 g. The “MARS” registered these data during observations of 1972 1978. From these data 5160 meteor streams are singled out. New classification of streams is made in view of their structure. The study of meteor stream orbits from the KHNURE data bank allow to predict orbits of a big number of undiscovered “dangerous” NEOs.

  1. Frequency-agile dual-frequency lidar for integrated coherent radar-lidar architectures.

    PubMed

    Vercesi, Valeria; Onori, Daniel; Laghezza, Francesco; Scotti, Filippo; Bogoni, Antonella; Scaffardi, Mirco

    2015-04-01

    We propose a novel architecture for implementing a dual-frequency lidar (DFL) exploiting differential Doppler shift measurement. The two frequency tones, needed for target velocity measurements, are selected from the spectrum of a mode-locked laser operating in the C-band. The tones' separation is easily controlled by using a programmable wavelength selective switch, thus allowing for a dynamic trade-off among robustness to atmospheric turbulence and sensitivity. Speed measurements for different tone separations equal to 10, 40, 80, and 160 GHz are demonstrated, proving the system's capability of working in different configurations. Thanks to the acquisition system based on an analog-to-digital converter and digital-signal processing, real-time velocity measurements are demonstrated. The MLL-based proposed architecture enables the integration of the DFL with a photonic-based radar that exploits the same laser for generating and receiving radio-frequency signal with high performance, thus allowing for simultaneous or complementary target observations by exploiting the advantages of both radar and lidar. PMID:25831332

  2. Frequency-agile dual-frequency lidar for integrated coherent radar-lidar architectures.

    PubMed

    Vercesi, Valeria; Onori, Daniel; Laghezza, Francesco; Scotti, Filippo; Bogoni, Antonella; Scaffardi, Mirco

    2015-04-01

    We propose a novel architecture for implementing a dual-frequency lidar (DFL) exploiting differential Doppler shift measurement. The two frequency tones, needed for target velocity measurements, are selected from the spectrum of a mode-locked laser operating in the C-band. The tones' separation is easily controlled by using a programmable wavelength selective switch, thus allowing for a dynamic trade-off among robustness to atmospheric turbulence and sensitivity. Speed measurements for different tone separations equal to 10, 40, 80, and 160 GHz are demonstrated, proving the system's capability of working in different configurations. Thanks to the acquisition system based on an analog-to-digital converter and digital-signal processing, real-time velocity measurements are demonstrated. The MLL-based proposed architecture enables the integration of the DFL with a photonic-based radar that exploits the same laser for generating and receiving radio-frequency signal with high performance, thus allowing for simultaneous or complementary target observations by exploiting the advantages of both radar and lidar.

  3. Ground Penetrating Radar Field Studies of Lunar-Analog Geologic Settings and Processes: Barringer Meteor Crater and Northern Arizona Volcanics

    NASA Astrophysics Data System (ADS)

    Russell, P. S.; Grant, J. A.; Williams, K. K.; Bussey, B.

    2010-12-01

    Ground-Penetrating Radar (GPR) data from terrestrial analog environments can help constrain models for evolution of the lunar surface, aid in interpretation of orbital SAR data, and help predict what might be encountered in the subsurface during future, landed, scientific or engineering operations on the Moon. GPR can yield insight into the physical properties, clast-size distribution, and layering of the subsurface, granting a unique view of the processes affecting an area over geologic time. The purpose of our work is to demonstrate these capabilities at sites at which geologic processes, settings, and/or materials are similar to those that may be encountered on the moon, especially lava flows, impact-crater ejecta, and layered materials with varying properties. We present results from transects obtained at Barringer Meteor Crater, SP Volcano cinder cone, and Sunset Crater Volcano National Monument, all in northern Arizona. Transects were taken at several sites on the ejecta of Meteor Crater, all within a crater radius (~400 m) of the crater rim. Those taken across ejecta lobes or mounds reveal the subsurface contact of the ejecta upper surface and overlying, embaying sediments deposited by later alluvial, colluvial, and/or aeolian processes. Existing mine shafts and pits on the south side of the crater provide cross sections of the subsurface against which we compare adjacent GPR transects. The ‘actual’ number, size, and depth of clasts in the top 1-2 m of the subsurface are estimated from photos of the exposed cross sections. In GPR radargrams, reflections attributed to blocks in the top 2-5 m of the subsurface are counted, and their depth distribution noted. Taking GPR measurements along a transect at two frequencies (200 and 400 MHz) and to various depths, we obtain the ratio of the actual number of blocks in the subsurface to the number detectable with GPR, as well as an assessment of how GPR detections in ejecta decline with depth and depend on antenna

  4. First results with a new-generation meteor radar on King George Island: Mean and Tidal Wind and Gravity Wave Momentum Flux Measurements over the Drake Passage

    NASA Astrophysics Data System (ADS)

    Fritts, D.; Janches, D.; Iimura, H.; Hocking, W. K.; Bageston, J. V.; Leme, N. P.

    2011-12-01

    A new-generation meteor radar was installed at the Brazilian Antarctic Comandante Ferraz Base (62.1S) in March 2010. This talk describes the motivations for the radar location, its measurement capabilities, and comparisons of measured mean winds, tides, and gravity wave momentum fluxes from April to June of 2010 and 2011 with those by a similar radar on Tierra del Fuego (53.8S). Motivations for the radars include the "hotspot" of small-scale gravity wave activity extending from the troposphere into the mesosphere and lower thermosphere (MLT) centered over the Drake Passage, the maximum of the semidiurnal tide at these latitudes, and the lack of other MLT wind measurements in this latitude band. Mean winds are seen to be strongly modulated at planetary wave and longer periods and to exhibit strong coherence over the two radars at shorter time scales as well as systematic seasonal variations. The semidiurnal tide contribute most to the large-scale winds over both radars, with maximum tidal amplitudes during May and maxima at the highest altitudes varying from ~20 to >70 m/s. In contrast, the diurnal tide and various planetary waves achieve maximum winds of ~10 to 20 m/s. Monthly-mean gravity wave momentum fluxes appear to reflect the occurrence of significant sources at lower altitudes, with relatively small zonal fluxes over both radars, but with significant, and opposite, meridional momentum fluxes below ~85 km. These suggest gravity waves propagating away from the Drake Passage at both sites, and may indicate an important source region accounting in part for this "hotspot".

  5. Global Variation of Meteor Trail Plasma Turbulence

    NASA Technical Reports Server (NTRS)

    Dyrud, L. P.; Hinrichs, J.; Urbina, J.

    2011-01-01

    We present the first global simulations on the occurrence of meteor trail plasma irregularities. These results seek to answer the following questions: when a meteoroid disintegrates in the atmosphere will the resulting trail become plasma turbulent, what are the factors influencing the development of turbulence, and how do they vary on a global scale. Understanding meteor trail plasma turbulence is important because turbulent meteor trails are visible as non-specular trails to coherent radars, and turbulence influences the evolution of specular radar meteor trails, particularly regarding the inference of mesospheric temperatures from trail diffusion rates, and their usage for meteor burst communication. We provide evidence of the significant effect that neutral atmospheric winds and density, and ionospheric plasma density have on the variability of meteor trail evolution and the observation of nonspecular meteor trails, and demonstrate that trails are far less likely to become and remain turbulent in daylight, explaining several observational trends using non-specular and specular meteor trails.

  6. A meteoroid stream survey using the Canadian Meteor Orbit Radar. II: Identification of minor showers using a 3D wavelet transform

    NASA Astrophysics Data System (ADS)

    Brown, P.; Wong, D. K.; Weryk, R. J.; Wiegert, P.

    2010-05-01

    A 7 year survey using the Canadian Meteor Orbit Radar (CMOR), a specular backscattering orbital radar, has produced three million individually measured meteoroid orbits for particles with mean mass near 10 -7 kg. We apply a 3D wavelet transform to our measured velocity vectors, partitioning them into 1° solar longitude bins while stacking all 7 years of data into a single "virtual" year to search for showers which show annual activity and last for at least 3 days. Our automated stream search algorithm has identified 117 meteor showers. We have recovered 42 of the 45 previously described streams from our first reconnaissance survey (Brown, P., Weryk, R.J., Wong, D.K., Jones, J. [2008]. Icarus 195, 317-339). Removing possible duplicate showers from the automated results leaves 109 total streams. These include 42 identified in survey I and at least 62 newly identified streams. Our large data sample and the enhanced sensitivity of the 3D wavelet search compared to our earlier survey have allowed us to extend the period of activity for several major showers. This includes detection of the Geminid shower from early November to late December and the Quadrantids from early November to mid-January. Among our newly identified streams are the Theta Serpentids which appears to be derived from 2008 KP and the Canum Venaticids which have a similar orbit to C/1975 X1 (Sato). We also find evidence that nearly 60% of all our streams are part of seven major stream complexes, linked via secular invariants.

  7. Frequency agile optical parametric oscillator

    DOEpatents

    Velsko, S.P.

    1998-11-24

    The frequency agile OPO device converts a fixed wavelength pump laser beam to arbitrary wavelengths within a specified range with pulse to pulse agility, at a rate limited only by the repetition rate of the pump laser. Uses of this invention include Laser radar, LIDAR, active remote sensing of effluents/pollutants, environmental monitoring, antisensor lasers, and spectroscopy. 14 figs.

  8. Frequency agile optical parametric oscillator

    DOEpatents

    Velsko, Stephan P.

    1998-01-01

    The frequency agile OPO device converts a fixed wavelength pump laser beam to arbitrary wavelengths within a specified range with pulse to pulse agility, at a rate limited only by the repetition rate of the pump laser. Uses of this invention include Laser radar, LIDAR, active remote sensing of effluents/pollutants, environmental monitoring, antisensor lasers, and spectroscopy.

  9. EISCAT meteor observations

    NASA Astrophysics Data System (ADS)

    Häggström, Ingemar; Pellinen-Wannberg, Asta; Westman, Assar; Vierinen, Juha; Brosch, Noah

    2010-05-01

    We present preliminary results from a 24-hour run to observe meteors conducted at EISCAT (Tromsø, Norway) on 17-18 December 2009, when no strong meteor showers were active. These pertain to the single-beam echoes detected at zenith by the Tromsø VHF and UHF systems and are compared with similar results obtained in 2008 during the peak of the Geminid meteor shower (Brosch et al. 2009). We present statistics of the echoes and concentrate, in particular, on the population of high-altitude echoes defined as being at 150-km altitude or higher, and on decelerating meteors. We also report on the character of tristatic echoes detected during the same period around 100-km altitude using the UHF receiver stations at Kiruna (Sweden) and Sodankylä (Finland), and on some low-altitude trails detected during this run. References: Brosch, N., Häggström, I., Pellinen-Wannberg, A., Westman, A. "Unusual features in high statistics radar meteor studies at EISCAT" Monthly Notices of the Royal Astronomical Society, 2009.

  10. Positioning Agility

    NASA Astrophysics Data System (ADS)

    Oza, Nilay; Abrahamsson, Pekka; Conboy, Kieran

    Agile methods are increasingly adopted by European companies. Academics too are conducting numerous studies on different tenets of agile methods. Companies often feel proud in marketing themselves as ‘agile’. However, the true notion of ‘being agile’ seems to have been overlooked due to lack of positioning of oneself for agility. This raises a call for more research and interactions between academia and the industry. The proposed workshop refers to this call. It will be highly relevant to participants, interested in positioning their company’s agility from organizational, group or project perspectives. The positioning of agility will help companies to better align their agile practices with stakeholder values. Results of the workshop will be shared across participants and they will also have opportunity to continue their work on agile positioning in their companies. At broader level, the work done in this workshop will contribute towards developing Agile Positioning System.

  11. Meteor44 Video Meteor Photometry

    NASA Technical Reports Server (NTRS)

    Swift, Wesley R.; Suggs, Robert M.; Cooke, William J.

    2004-01-01

    Meteor44 is a software system developed at MSFC for the calibration and analysis of video meteor data. The dynamic range of the (8bit) video data is extended by approximately 4 magnitudes for both meteors and stellar images using saturation compensation. Camera and lens specific saturation compensation coefficients are derived from artificial variable star laboratory measurements. Saturation compensation significantly increases the number of meteors with measured intensity and improves the estimation of meteoroid mass distribution. Astrometry is automated to determine each image's plate coefficient using appropriate star catalogs. The images are simultaneously intensity calibrated from the contained stars to determine the photon sensitivity and the saturation level referenced above the atmosphere. The camera s spectral response is used to compensate for stellar color index and typical meteor spectra in order to report meteor light curves in traditional visual magnitude units. Recent efforts include improved camera calibration procedures, long focal length 'streak' meteor photometry and two-station track determination. Meteor44 has been used to analyze data from the 2001, 2002 and 2003 MSFC Leonid observational campaigns as well as several lesser showers. The software is interactive and can be demonstrated using data from recent Leonid campaigns.

  12. Meteor44 Video Meteor Photometry

    NASA Technical Reports Server (NTRS)

    Swift, Wesley R.; Suggs, Robert M.; Cooke, William J.

    2004-01-01

    Meteor44 is a software system developed at MSFC for the calibration and analysis of video meteor data. The dynamic range of the (8bit) video data is extended by approximately 4 magnitudes for both meteors and stellar images using saturation compensation. Camera and lens specific saturation compensation coefficients are derived from artificial variable star laboratory measurements. Saturation compensation significantly increases the number of meteors with measured intensity and improves the estimation of meteoroid mass distribution. Astrometry is automated to determine each image s plate coefficient using appropriate star catalogs. The images are simultaneously intensity calibrated from the contained stars to determine the photon sensitivity and the saturation level referenced above the atmosphere. The camera s spectral response is used to compensate for stellar color index and typical meteor spectra in order to report meteor light curves in traditional visual magnitude units. Recent efforts include improved camera calibration procedures, long focal length "streak" meteor photome&y and two-station track determination. Meteor44 has been used to analyze data from the 2001.2002 and 2003 MSFC Leonid observational campaigns as well as several lesser showers. The software is interactive and can be demonstrated using data from recent Leonid campaigns.

  13. Determination of meteor flux distribution over the celestial sphere

    NASA Technical Reports Server (NTRS)

    Andreev, V. V.; Belkovich, O. I.; Filimonova, T. K.; Sidorov, V. V.

    1992-01-01

    A new method of determination of meteor flux density distribution over the celestial sphere is discussed. The flux density was derived from observations by radar together with measurements of angles of arrival of radio waves reflected from meteor trails. The role of small meteor showers over the sporadic background is shown.

  14. Video Meteor Fluxes

    NASA Technical Reports Server (NTRS)

    Campbell-Brown, M. D.; Braid, D.

    2011-01-01

    The flux of meteoroids, or number of meteoroids per unit area per unit time, is critical for calibrating models of meteoroid stream formation and for estimating the hazard to spacecraft from shower and sporadic meteors. Although observations of meteors in the millimetre to centimetre size range are common, flux measurements (particularly for sporadic meteors, which make up the majority of meteoroid flux) are less so. It is necessary to know the collecting area and collection time for a given set of observations, and to correct for observing biases and the sensitivity of the system. Previous measurements of sporadic fluxes are summarized in Figure 1; the values are given as a total number of meteoroids striking the earth in one year to a given limiting mass. The Gr n et al. (1985) flux model is included in the figure for reference. Fluxes for sporadic meteoroids impacting the Earth have been calculated for objects in the centimeter size range using Super-Schmidt observations (Hawkins & Upton, 1958); this study used about 300 meteors, and used only the physical area of overlap of the cameras at 90 km to calculate the flux, corrected for angular speed of meteors, since a large angular speed reduces the maximum brightness of the meteor on the film, and radiant elevation, which takes into account the geometric reduction in flux when the meteors are not perpendicular to the horizontal. They bring up corrections for both partial trails (which tends to increase the collecting area) and incomplete overlap at heights other than 90 km (which tends to decrease it) as effects that will affect the flux, but estimated that the two effects cancelled one another. Halliday et al. (1984) calculated the flux of meteorite-dropping fireballs with fragment masses greater than 50 g, over the physical area of sky accessible to the MORP fireball cameras, counting only observations in clear weather. In the micron size range, LDEF measurements of small craters on spacecraft have been used to

  15. The ALTAIR Meteor Measurements Program

    NASA Technical Reports Server (NTRS)

    Cooke, William J.

    2007-01-01

    Established in late 2006, the Meteor Measurements Program is in the process of using the ALTAIR radar located on Kwajelein Atoll to obtain radar observations of sporadic and shower meteoroids. The goals are to determine meteoroid masses, orbits, ballistic coefficients and densities, which shall be provided to the Meteoroid Environment Office (MEO) at Marshall Space Flight Center. These data and analyses shall then be used by the MEO to 1) Add a realistic density distribution to the new Meteoroid Engineering Model (MEM), which is the specified environment for vehicle design in the NASA Constellation (return to Moon) program. This program is the implementation of President Bush's Vision for Space Exploration (VSE). 2) Investigate the meteoroid velocity distribution at smaller masses. 3) Strive to understand the differences (biases) in meteoroid observations produced by systems like ALTAIR and those of the meteor patrol radars, such as the University of Western Ontario's CMOR system. This paper outlines the program details and its progress.

  16. An FDTD model of scattering from meteor head plasma

    NASA Astrophysics Data System (ADS)

    Marshall, R. A.; Close, S.

    2015-07-01

    We have developed a three-dimensional finite difference time domain (FDTD) model of scattering of radar waves from meteor head plasma. The model treats the meteor head plasma as a cold, collisional, and magnetized plasma, and solves Maxwell's equations and the Langevin equation simultaneously and self-consistently in and around the plasma. We use this model to investigate scattering of radar waves from a meteor head (the "head echo") under a range of plasma densities, meteor scale sizes, and wave frequencies. In this way we relate the radar cross section (RCS) to these variable parameters. We find that computed RCS disagrees with previous analytical theory at certain meteor sizes and densities, in some cases by over an order of magnitude. We find that the calculated meteor head RCS is monotonically related to the "overdense area" of the meteor, defined as the cross-section area of the part of the meteor where the plasma frequency exceeds the wave frequency. These results provides a physical measure of the meteor size and density that can be inferred from measured RCS values from ground-based radars. Meteoroid mass can then be inferred from the meteor plasma distribution using established methods.

  17. Database of Properties of Meteors

    NASA Technical Reports Server (NTRS)

    Suggs, Rob; Anthea, Coster

    2006-01-01

    A database of properties of meteors, and software that provides access to the database, are being developed as a contribution to continuing efforts to model the characteristics of meteors with increasing accuracy. Such modeling is necessary for evaluation of the risk of penetration of spacecraft by meteors. For each meteor in the database, the record will include an identification, date and time, radiant properties, ballistic coefficient, radar cross section, size, density, and orbital elements. The property of primary interest in the present case is density, and one of the primary goals in this case is to derive densities of meteors from their atmospheric decelerations. The database and software are expected to be valid anywhere in the solar system. The database will incorporate new data plus results of meteoroid analyses that, heretofore, have not been readily available to the aerospace community. Taken together, the database and software constitute a model that is expected to provide improved estimates of densities and to result in improved risk analyses for interplanetary spacecraft. It is planned to distribute the database and software on a compact disk.

  18. Meteor Beliefs Project: ``Year of Meteors''

    NASA Astrophysics Data System (ADS)

    McBeath, Alastair; Drobnock, George J.; Gheorghe, Andrei Dorian

    2011-10-01

    We present a discussion linking ideas from a modern music album by Laura Veirs back to a turbulent time in American history 150 years ago, which inspired poet Walt Whitman to compose his poem "Year of Meteors", and the meteor beliefs of the period around 1859-1860, when collection of facts was giving way to analyses and theoretical explanations in meteor science.

  19. Agile Walker.

    PubMed

    Katz, Reuven

    2015-01-01

    The goal of the Agile Walker is to improve the outdoor mobility of healthy elderly people with some mobility limitations. It is a newly developed, all-terrain walker, equipped with an electric drive system and speed control that can assists elderly people to walk outdoors or to hike. The walker has a unique product design with an attractive look that will appeal to "active-agers" population. This paper describes product design requirements and the development process of the Agile Walker, its features and some preliminary testing results.

  20. Multi-Year CMOR Observations of the Geminid Meteor Shower

    NASA Technical Reports Server (NTRS)

    Webster, A. R.; Jones, J.

    2011-01-01

    The three-station Canadian Meteor Orbit Radar (CMOR) is used here to examine the Geminid meteor shower with respect to variation in the stream properties including the flux and orbital elements over the period of activity in each of the consecutive years 2005 2008 and the variability from year to year. Attention is given to the appropriate choice and use of the D-criterion in the separating the shower meteors from the sporadic background.

  1. The Meteor Meter.

    ERIC Educational Resources Information Center

    Eggensperger, Martin B.

    2000-01-01

    Introduces the Meteor Scatter Project (MSP) in which high school students build an automated meteor observatory and learn to monitor meteor activity. Involves students in activities such as radio frequency survey, antenna design, antenna construction, manual meteor counts, and computer board configuration and installation. (YDS)

  2. EISCAT observations of meteors from the sporadic complex

    NASA Astrophysics Data System (ADS)

    Brosch, Noah; Häggström, Ingemar; Pellinen-Wannberg, Asta

    2013-10-01

    We report meteor observation with the European Incoherent Scatter Scientific Association (EISCAT) radars obtained during a continuous 24-h period in 2009 December. The period, just after the Geminid meteor shower, was selected to have no strong meteor shower activity to allow a comparison with our previous observations collected during the 2008 Geminid shower. During the 2009 run, we used the very high frequency (VHF) and ultrahigh frequency systems, but most of the results presented here were derived from the VHF data. We discuss the statistical properties of the radar echoes, their Doppler velocity and altitude distributions, their radar cross-section, etc. We concentrate, as in our previous paper, on the population of high-altitude echoes, which we clearly detect, and discuss these specifically. We recognize a few echoes with positive Doppler velocities as produced by meteoroids that presumably entered the atmosphere at ˜grazing incidence angles and were leaving it when detected by radar. We detect meteor echoes with essentially zero Doppler velocity, reported here for the first time, which we interpret as meteoroids moving almost perpendicular to the beam and producing specular reflections off the meteor trail. We discuss meteors detected with tristatic measurements for which we find bunching in azimuth and depression angle that depends on the time of the day. Finally, we report again of the lack of extreme velocity meteors, a fact that weakens significantly the claim of the existence and abundance of interstellar meteors.

  3. Archive of radar observations of meteors in Tomsk in 1965-1966. (Russian Title: Архив радиолокационных наблюдений метеоров в Томске в 1965-1966 гг.)

    NASA Astrophysics Data System (ADS)

    Ryabova, G. O.

    2010-12-01

    The archive of data of radar observations of Geminid, Quadrantid, Daytime Arietid, Perseid, Ursid, Lyrid, Orionid and Leonid meteor showers in Tomsk in 1965-1966 is described. In certain cases registrations of the sporadic background before and after a shower exist. Primary data of echo registrations contain time of a registration, distance, duration and amplitude of an echo, allowing to obtain corresponding distributions essential for calculation of the incident flux density of meteors. Work on the archive digitization has been started.

  4. Meteors in the Earth's Atmosphere

    NASA Astrophysics Data System (ADS)

    Murad, Edmond; Williams, Iwan P.

    2002-09-01

    1. Introduction Iwan Williams and Edmond Murad; 2. The evolution of meteoroid streams Iwan Williams; 3. Space dust measurements Eberhard Grun, Valeri Dikarev, Harald Kruger and Markus Landgraf; 4. Extraterrestrial dust in the near-Earth environment George Flynn; 5. Detection and analysis procedures for visual photographic and image intensified CCD meteor observations Robert Hawkes; 6. Radar observations W. Jack Baggaley; 7. Meteor trails as observed by Lidar Ulf von Zahn, J. Hoffner and William McNeil; 8. In situ measurements of meteoritic ions Joseph Grebowsky and Arthur Aikin; 9. Collected extraterrestrial materials: interplanetary dust particles, micrometeorites, meteorites, and meteoritic dust Frans Rietmeijer; 10. Meteoroid impacts on spacecraft; Luigi Foschini; 11. Models of meteoritic metals in the atmosphere William McNeil, Edmond Murad and John Plane; 12. Laboratory studies of meteoritic metal chemistry John Plane; 13. Summary and future outlook Edmond Murad and Iwan Williams.

  5. Mesospheric temperature estimation from meteor decay times during Geminids meteor shower

    NASA Astrophysics Data System (ADS)

    Kozlovsky, Alexander; Lukianova, Renata; Shalimov, Sergey; Lester, Mark

    2016-02-01

    Meteor radar observations at the Sodankylä Geophysical Observatory (67° 22'N, 26° 38'E, Finland) indicate that the mesospheric temperature derived from meteor decay times is systematically underestimated by 20-50 K during the Geminids meteor shower which has peak on 13 December. A very good coincidence of the minimum of routinely calculated temperature and maximum of meteor flux (the number of meteors detected per day) was observed regularly on that day in December 2008-2014. These observations are for a specific height-lifetime distribution of the Geminids meteor trails and indicate a larger percentage of overdense trails compared to that for sporadic meteors. A consequence of this is that the routine estimates of mesospheric temperature during the Geminids are in fact underestimates. The observations do, however, indicate unusual properties (e.g., mass, speed, or chemical composition) of the Geminids meteoroids. Similar properties were found also for Quadrantids in January 2009-2015, which like the Geminids has as a parent body an asteroid, but not for other meteor showers.

  6. Diurnal variation of overdense meteor echo duration and ozone

    NASA Technical Reports Server (NTRS)

    Simek, Milos

    1992-01-01

    The diurnal variation of the median duration of overdense sporadic radar meteor echoes is examined. The meteors recorded in August, December, and January by the Ondrejov meteor radar during the period 1958-1990 were used for the analysis. A maximum median echo duration 1-3 hours after the time of local sunrise in the meteor region confirms the already known sunrise effect. Minimum echo duration occurring at the time of sunset seems to be the most important point of diurnal variation of the echo duration, when ozone is no longer dissociated by solar UV radiation. The effect of diurnal changes of the echo duration should be considered when the mass distribution of meteor showers is analyzed.

  7. Quadrantid Meteor, 2013

    NASA Video Gallery

    An allsky camera in New Mexico captured a brief video of this Quadrantid fireball meteor on Jan. 3, 2013 at 2:04 a.m. EST. The Quadrantid meteor shower occurs each January and derives its name from...

  8. Catalogue of representative meteor spectra

    NASA Astrophysics Data System (ADS)

    Vojáček, V.; Borovička, J.; Koten, P.; Spurný, P.; Štork, R.

    2016-01-01

    We present a library of low-resolution meteor spectra that includes sporadic meteors, members of minor meteor showers, and major meteor showers. These meteors are in the magnitude range from +2 to ‑3, corresponding to meteoroid sizes from 1 mm to10 mm. This catalogue is available online at the CDS for those interested in video meteor spectra.

  9. Catalogue of representative meteor spectra

    NASA Astrophysics Data System (ADS)

    Vojáček, V.; Borovička, J.; Koten, P.; Spurný, P.; Štork, R.

    2016-01-01

    We present a library of low-resolution meteor spectra that includes sporadic meteors, members of minor meteor showers, and major meteor showers. These meteors are in the magnitude range from +2 to -3, corresponding to meteoroid sizes from 1 mm to10 mm. This catalogue is available online at the CDS for those interested in video meteor spectra.

  10. A Conjugate Study of Mean Winds and Planetary Waves Employing Enhanced Meteor Radars at Rio Grande, Argentina (53.8degS) and Juliusruh, Germany (54.6degN)

    NASA Technical Reports Server (NTRS)

    Fritts, D. C.; Imura, H.; Lieberman, R.; Janches, D.; Singer, W.

    2011-01-01

    Two meteor radars with enhanced power and sensitivity and located at closely conjugate latitudes (54.6degN and 53.8degS) are employed for inter-hemispheric comparisons of mean winds and planetary wave structures. Our study uses data from June 2008 through May 2010 during which both radars provided nearly continuous wind measurements from approx.80 to 100 km. Monthly mean winds at 53.8degS exhibit a somewhat stronger westward mean zonal jet in spring and early summer at lower altitudes and no westward monthly mean winds at higher altitudes. In contrast, westward mean winds of approx.5-10 m/s at 54.6degN extend to above 96 km during late winter and early spring each year. Equatorward monthly mean winds extend approximately from spring to fall equinox at both latitudes, with amplitudes of approx.5-10 m/s and more rapid decreases in amplitude at 54.6degN at higher altitudes. Meridional mean winds are more variable at both latitudes during fall and winter, with both poleward and equatorward monthly means indicating longer-period variability. Planetary waves seen in the 2-day mean data are episodic and variable at both sites, exhibit dominant periodicities of approx.8-10 and 16-20 days and are more confined to late fall and winter at 54.6degN. At both latitudes, planetary waves in the two period bands coincide closely in time and exhibit similar horizontal velocity covariances that are positive (negative) at 54.6degN (53.8degS) during peak planetary wave responses.

  11. Kinematic Characteristics of Meteor Showers by Results of the Combined Radio-Television Observations

    NASA Astrophysics Data System (ADS)

    Narziev, Mirhusen

    2016-07-01

    One of the most important tasks of meteor astronomy is the study of the distribution of meteoroid matter in the solar system. The most important component to address this issue presents the results of measurements of the velocities, radiants, and orbits of both showers and sporadic meteors. Radiant's and orbits of meteors for different sets of data obtained as a result of photographic, television, electro-optical, video, Fireball Network and radar observations have been measured repeatedly. However, radiants, velocities and orbits of shower meteors based on the results of combined radar-optical observations have not been sufficiently studied. In this paper, we present a methods for computing the radiants, velocities, and orbits of the combined radar-TV meteor observations carried out at HisAO in 1978-1980. As a result of the two-year cycle of simultaneous TV-radar observations 57 simultaneous meteors have been identified. Analysis of the TV images has shown that some meteor trails appeared as dashed lines. Among the simultaneous meteors of d-Aquariids 10 produced such dashed images, and among the Perseids there were only 7. Using a known method, for such fragmented images of simultaneous meteors - together with the measured radar distance, trace length, and time interval between the segments - allowed to determine meteor velocity using combined method. In addition, velocity of the same meteors was measured using diffraction and radar range-time methods based on the results of radar observation. It has been determined that the mean values of meteoroid velocity based on the combined radar-TV observations are greater in 1 ÷ 3 km / c than the averaged velocity values measured using only radar methods. Orbits of the simultaneously observed meteors with segmented photographic images were calculated on the basis of the average velocity observed using the combined radar-TV method. The measured results of radiants velocities and orbital elements of individual meteors

  12. Various meteor scenes I: the perception and the conception of a 'meteor shower'

    NASA Astrophysics Data System (ADS)

    Koseki, Masahiro

    2014-10-01

    Not all 'established showers' are recognisable by every method. Some might be lost ('dead') or have recurrent (periodic) nature and are not observable annually. Some are dominated by faint meteors and not observable visually but by radar systems. Other showers are rich in fireballs and their low meteor rates make them a good target for video and photographic observations, while visual observers may not notice their activity because of the low rates. The perception limit in magnitude differs between the observing methods on the one hand, but depends on the magnitude ratios of shower meteors on the other hand. Differences in the definition of a 'meteor shower'/'meteoroid stream' work important roles composing the shower list and we need to know how much various researchers' definitions differ. Depending whether we use observational raw data of the visible meteor shower or orbital elements of the meteoroid stream this may lead to either an obvious meteor showers or an undetectable stream. This paper (paper I) describes the reasons why we can see a meteor shower and why not, Paper II proves the condition by the example of Cygnid-Draconid complex, especially for the κ-Cygnids, and Paper III looks at the different views of several minor showers from the different kind observations.

  13. Variations of Magnitude and Ionization Along the Traces of the Same Meteors

    NASA Astrophysics Data System (ADS)

    Narziev, Mirhusen

    2016-07-01

    Using the results of simultaneous television and basic radar observations of meteors from points 4-5, received during the periods of activity of the main annual meteor showers α - Kaprikornis, δ - Akvarids, Geminids, Quadrantids and Orionids in 1979 in GisAO, the variation of magnitude and linear electronic density along a traces of the same meteors were studied. It was determined that for meteors with velocities of 23-69 km/c the course of variation of magnitude and linear electronic density along the traces of the same meteors were fairly coordinated among themselves. The received results are compared with the similar data received for weaker meteors in Harward (Illinois). It is concluded that the difference between radar-tracking and photographic magnitude depends on the speed of meteors.

  14. Apparatus for photographing meteors

    NASA Technical Reports Server (NTRS)

    Harvey, G. A. (Inventor)

    1973-01-01

    Apparatus for photographing meteors in a selected area of the sky is described. A photomultiplier is pointed in the direction of the area. When a meteor passes through the area the signal output of the photomultiplier increases. Means are provided that activate a camera, pointed at the area, in response to an increased signal from the photomultiplier. Hence, the camera photographs the selected are only while meteors are likely to be passing through the area.

  15. Practical Meteor Stream Forecasting

    NASA Technical Reports Server (NTRS)

    Cooke, William J.; Suggs, Robert M.

    2003-01-01

    Inspired by the recent Leonid meteor storms, researchers have made great strides in our ability to predict enhanced meteor activity. However, the necessary calibration of the meteor stream models with Earth-based ZHRs (Zenith Hourly Rates) has placed emphasis on the terran observer and meteor activity predictions are published in such a manner to reflect this emphasis. As a consequence, many predictions are often unusable by the satellite community, which has the most at stake and the greatest interest in meteor forecasting. This paper suggests that stream modelers need to pay more attention to the needs of this community and publish not just durations and times of maxima for Earth, but everything needed to characterize the meteor stream in and out of the plane of the ecliptic, which, at a minimum, consists of the location of maximum stream density (ZHR) and the functional form of the density decay with distance from this point. It is also suggested that some of the terminology associated with meteor showers may need to be more strictly defined in order to eliminate the perception of crying wolf by meteor scientists. An outburst is especially problematic, as it usually denotes an enhancement by a factor of 2 or more to researchers, but conveys the notion of a sky filled with meteors to satellite operators and the public. Experience has also taught that predicted ZHRs often lead to public disappointment, as these values vastly overestimate what is seen.

  16. On the spatial structure of the Perseids meteor stream

    NASA Technical Reports Server (NTRS)

    Andreev, G. V.; Rubtsov, L. N.; Tarasova, I. I.

    1987-01-01

    The analysis of radar observations of the Perseid meteor stream conducted in an ionospherical laboratory in the period from 1964 to 1981 is presented. The Perseids meteor rates were determined by the fluctuation method. Analysis of their hourly distributions showed that the stream maximum position is different for different years, i.e., the stream nodal position is constantly changing. The results of the analysis are presented and discussed.

  17. Rare Double Quadrantid Meteor Sighting

    NASA Video Gallery

    The wide-field meteor camera at NASA's Marshall Space Flight Center recorded these two simultaneous Quadrantid meteors on Jan. 4 at approximately 5 a.m. EST. Moving at 92,000 mph, the meteors flash...

  18. Meteor Beliefs Project: Introduction

    NASA Astrophysics Data System (ADS)

    McBeath, A.; Gheorghe, A. D.

    2003-05-01

    A new project to investigate beliefs in meteors and meteoric phenomena in past and present times using chiefly folklore, mythology, prose and poetic literature, is described. Some initial examples are given, along with a bibliography of relevant items already in print in IMO publications.

  19. Meteors and meteorites spectra

    NASA Astrophysics Data System (ADS)

    Koukal, J.; Srba, J.; Gorková, S.; Lenža, L.; Ferus, M.; Civiš, S.; Knížek, A.; Kubelík, P.; Kaiserová, T.; Váňa, P.

    2016-01-01

    The main goal of our meteor spectroscopy project is to better understand the physical and chemical properties of meteoroids. Astrometric and spectral observations of real meteors are obtained via spectroscopic CCD video systems. Processed meteor data are inserted to the EDMOND database (European viDeo MeteOr Network Database) together with spectral information. The fully analyzed atmospheric trajectory, orbit and also spectra of a Leonid meteor/meteoroid captured in November 2015 are presented as an example. At the same time, our target is the systematization of spectroscopic emission lines for the comparative analysis of meteor spectra. Meteoroid plasma was simulated in a laboratory by laser ablation of meteorites samples using an (ArF) excimer laser and the LIDB (Laser Induced Dielectric Breakdown) in a low pressure atmosphere and various gases. The induced plasma emissions were simultaneously observed with the Echelle Spectrograph and the same CCD video spectral camera as used for real meteor registration. Measurements and analysis results for few selected meteorite samples are presented and discussed.

  20. Dynamics of meteor streams

    NASA Technical Reports Server (NTRS)

    Babadjanov, P. B.; Obrubov, Yu. U.

    1987-01-01

    The overwhelming majority of meteor streams are generally assumed to be formed due to the decay of comets. The most effective process of the release of solid particles from a cometary nucleus is their ejection by sublimating gases when the comet approaches the Sun. The results of investigation of the Geminids and Quadrantids meteor stream evolution show that under the influence of planetary perturbations, the stream may originally be flat but then thicken depending on the variation range of orbital inclinations. Eventually, due to planetary perturbations, a meteor stream may take such a shape as to cause the start of several active showers at different solar longitudes.

  1. Minor meteor shower activity

    NASA Astrophysics Data System (ADS)

    Rendtel, J.

    2016-01-01

    Video meteor observations provide us with data to analyze structures in minor meteor showers or weak features in flux profiles. Samples obtained independently by other techniques allow to calibrate the data sets and to improve the confidence of results as demonstrated with a few results. Both, the confirmation of events predicted by model calculation and the input of observational data to improve the modelling results may help to better understand meteoroid stream evolution processes. Furthermore, calibrated data series can be used for studies of the long-term evolution of meteor shower activity.

  2. Optical electronics for meteor observations

    NASA Technical Reports Server (NTRS)

    Shafiev, R. I.; Mukhamednazarov, S.; Atamas, I. A.

    1987-01-01

    Spectral observations of meteors have been carried out for several years using an optical electronics facility. Interest has centered on faint meteors and their trails in the period of intensive meteor showers. Over 800 meteors were registered during the observation period, with spectrograms obtained for 170 of these. A total of 86 meteors were photographed from two sites and for 25 of these spectrograms of the meteors as well as their trails were obtained. All meteors have undergone routine processing in order to determine atmospheric characteristics. Results are discussed.

  3. Current trends in meteor spectroscopy

    NASA Technical Reports Server (NTRS)

    Millman, P. M.

    1982-01-01

    The history of progress over more than a century in meteor spectroscopy is summarized. The observational data were originally visual records, but in the beginning of the 20th century photography of meteor spectra was undertaken. In the forties, 60 meteor spectra were photographed. Interest in the upper atmosphere led to the development of more efficient meteor cameras which employ replica gratings, and electronic image intensification systems recordings on video tape which resulted in the availability of several thousand meteor spectra.

  4. Meteor Beliefs Project: Musical Meteors, meteoric imagery as used in near-contemporary song lyrics

    NASA Astrophysics Data System (ADS)

    McBeath, Alastair; Gheorghe, Andrei Dorian

    2010-01-01

    Items collected from contemporary song lyrics featuring meteoric imagery, or inspired by meteors, are given, with some discussion. While not a major part of the Meteor Beliefs Project, there are points of interest in how such usage may become passed into popular beliefs about meteors.

  5. Pulse-level interference and meteor processing of Arecibo ISR data

    NASA Astrophysics Data System (ADS)

    Wen, C.-H.; Briczinski, S. J.; Livneh, D. J.; Doherty, J. F.; Mathews, J. D.

    2007-07-01

    We introduce a simple but effective order statistics filter for the pulse-level interference and meteor processing of Arecibo ionosphere observation data. Using this filter and the techniques introduced by Wen et al. [2005. Adaptive filtering for the separation of incoherent scatter and meteor signals for Arecibo Observation Data. Journal of Atmospheric and Solar-Terrestrial Physics 67, 1190 1195] we effectively remove/separate the unwanted signals, such as impulsive interference and meteor returns, encountered during incoherent scatter radar (ISR) observations of the ionosphere. We further analyze the separated signals to obtain uniquely “cleaned” incoherent scatter power data and scientifically valuable meteor parameters. We present the processed incoherent scatter results from 22/23 March 2004 observations and the altitude and the speed distributions of the separated meteor signals. The nighttime photochemical E-region is clearly revealed for the first time as a result of meteor and interference removal. Additionally, these results reveal the first major bias in large aperture radar meteor headecho results—the meteor speed distribution is flattened by the absence of at least 50% of the events with duration less than 10 ms revealed by meteor-specific observations. Meteor data derived from standard incoherent scatter data always displays this bias.

  6. Echoes from the Sky: The Plasma Physics of Meteors Trails

    NASA Astrophysics Data System (ADS)

    Oppenheim, Meers

    2002-11-01

    Since ancient times people have witnessed the spectacular pyrotechnics caused by impacts of high velocity particles with the Earth's upper atmosphere. Today, we study the plasma created by ablating meteors in order to better understand the Earth's space environment, the dynamics and composition of the upper atmosphere and the primordial state of the solar system. Large aperture radars, probing the atmosphere between 75 and 130 km, will typically observe a couple of micro-meteors every minute. Until recently, meteor researchers assumed that these objects created columns of plasma that simply diffused away and used these assumptions to infer characteristics of the meteors and the surrounding atmosphere. However, meteor trails develop in the E-region ionosphere (90-150km altitude), where electrons are magnetized and ions are collisionally demagnetized, and where trails are subject to a set of plasma instabilities which develops into turbulent dynamics. This turbulence substantially modifies the dynamics and diffusion of the trails and explains a number of long-standing observational questions. We have explored this turbulent dynamics with kinetic simulations and theory and have used this knowledge to better interpret meteor radar signals.

  7. The 2014 KCG Meteor Outburst: Clues to a Parent Body

    NASA Technical Reports Server (NTRS)

    Moorhead, Althea V.; Brown, Peter G.; Spurny, Pavel; Cooke, William J.

    2015-01-01

    The Kappa Cygnid (KCG) meteor shower exhibited unusually high activity in 2014, producing ten times the typical number of meteors. The shower was detected in both radar and optical systems and meteoroids associated with the outburst spanned at least five decades in mass. In total, the Canadian Meteor Orbit Radar, European Network, and NASA All Sky and Southern Ontario Meteor Network produced thousands of KCG meteor trajectories. Using these data, we have undertaken a new and improved characterization of the dynamics of this little-studied, variable meteor shower. The Cygnids have a di use radiant and a significant spread in orbital characteristics, with multiple resonances appearing to play a role in the shower dynamics. We conducted a new search for parent bodies and found that several known asteroids are orbitally similar to the KCGs. N-body simulations show that the two best parent body candidates readily transfer meteoroids to the Earth in recent centuries, but neither produces an exact match to the KCG radiant, velocity, and solar longitude. We nevertheless identify asteroid 2001 MG1 as a promising parent body candidate.

  8. Historical aspects of radar atmospheric dynamics

    NASA Technical Reports Server (NTRS)

    Kato, Susumu

    1989-01-01

    A review of the history of radar techniques which have been applied to atmospheric observation is given. The author starts with ionosphere observation with the ionosonde, symbolizing as it does the earliest history of radar observation, and proceeds to later developments in radar observation such as the use of partial reflection, meteor, and incoherent scatter radars. Mesosphere stratosphere troposphere (MST) radars are discussed in terms of lower atmosphere observation.

  9. CAMS: Cameras for Allsky Meteor Surveillance to establish minor meteor showers

    NASA Astrophysics Data System (ADS)

    Jenniskens, P.; Gural, P. S.; Dynneson, L.; Grigsby, B. J.; Newman, K. E.; Borden, M.; Koop, M.; Holman, D.

    2011-11-01

    First results are presented from a newly developed meteoroid orbit survey, called CAMS - Cameras for Allsky Meteor Surveillance, which combines meteor detection algorithms for low-light video observations with traditional video surveillance tools. Sixty video cameras at three stations monitor the sky above 31° elevation. Goal of CAMS is to verify meteor showers in search of their parent comets among newly discovered near-Earth objects. This paper outlines the concept of operations, the hardware, and software methods used during operation and in the data reduction pipeline, and accompanies the data release of the first batch of meteoroid orbits. During the month of November 2010, 2169 precisely reduced meteoroid trajectories from 17 nights have an error in the apparent radiant of the trajectory <2° and error in speed <10%. Median values of the error are 0.31° and 0.53 km/s, respectively, sufficient to resolve the intrinsic dispersion of annual meteor showers and resolve minor showers from the sporadic background. The limiting visual magnitude of the cameras is +5.4, recording meteors of +4 magnitude and brighter, bright enough to stand out from the mostly fainter sporadic meteors detected as under dense radar echoes. CAMS readily detected all established showers (6) active during the clear nights in November. Of the showers that needed confirmation, we confirm the theta Aurigids (THA, IAU#390), the chi Taurids (CTA, IAU#388), and the omicron Eridanids (OER, IAU#338). We conclude that the iota November Aurigids (IAR, IAU#248) are in fact the combined activity of the theta Aurigids and chi Taurids, and this shower should be dismissed from the list. Finally, there is also a clustering consistent with the zeta Cancrids (ZCN, IAU#243), but we cannot exclude that this is lower perihelion dust belonging to the Orionid shower. Data are submitted to the IAU Meteor Data Center on a semi-regular basis, and can be accessed also at http://cams.seti.org.

  10. The Updated IAU MDC Catalogue of Photographic Meteor Orbits

    NASA Technical Reports Server (NTRS)

    Porubcan, V.; Svoren, J.; Neslusan, L.; Schunova, E.

    2011-01-01

    The database of photographic meteor orbits of the IAU Meteor Data Center at the Astronomical Institute SAS has gradually been updated. To the 2003 version of 4581 photographic orbits compiled from 17 different stations and obtained in the period 1936-1996, additional new 211 orbits compiled from 7 sources have been added. Thus, the updated version of the catalogue contains 4792 photographic orbits (equinox J2000.0) available either in two separate orbital and geophysical data files or a file with the merged data. All the updated files with relevant documentation are available at the web of the IAU Meteor Data Center. Keywords astronomical databases photographic meteor orbits 1 Introduction Meteoroid orbits are a basic tool for investigation of distribution and spatial structure of the meteoroid population in the close surroundings of the Earth s orbit. However, information about them is usually widely scattered in literature and often in publications with limited circulation. Therefore, the IAU Comm. 22 during the 1976 IAU General Assembly proposed to establish a meteor data center for collection of meteor orbits recorded by photographic and radio techniques. The decision was confirmed by the next IAU GA in 1982 and the data center was established (Lindblad, 1987). The purpose of the data center was to acquire, format, check and disseminate information on precise meteoroid orbits obtained by multi-station techniques and the database gradually extended as documented in previous reports on the activity of the Meteor Data Center by Lindblad (1987, 1995, 1999 and 2001) or Lindblad and Steel (1993). Up to present, the database consists of 4581 photographic meteor orbits (Lindblad et al., 2005), 63.330 radar determined orbit: Harvard Meteor Project (1961-1965, 1968-1969), Adelaide (1960-1961, 1968-1969), Kharkov (1975), Obninsk (1967-1968), Mogadish (1969-1970) and 1425 video-recordings (Lindblad, 1999) to which additional 817 video meteors orbits published by Koten el

  11. Meteor Beliefs Project: A Goodly Gallerye - William Fulke's "Meteors"

    NASA Astrophysics Data System (ADS)

    McBeath, Alastair; Gheorghe, Andrei Dorian

    2007-02-01

    An examination is presented of meteorically-relevant material from Englishman William Fulke's treatise on meteors from 1563, which encompassed much more than would modernly fall into this category, and which remained continually in print for over a century.

  12. The Toroidal Sporadic Sources: Looking for parent bodies of meteor streams

    NASA Astrophysics Data System (ADS)

    Pokorny, Petr; Brown, Peter G.; Moorhead, Althea V.; Wiegert, Paul; Janches, Diego

    2016-10-01

    The origin and characteristics of the North toroidal (NT) and South toroidal (ST) sporadic meteoroid sources remain poorly known. The NT was first noted in radar measurements in the late 1950s, however, its origin has puzzled astronomers for more than 50 years. The ST started being more thoroughly observed in recent years. The NT and ST meteoroid population shows orbital elements unlike any known contemporary parent population in the Solar System, dominated by particles with very high inclinations, modest semi-major axis values and low eccentricities. Recently, several dynamical models have suggested that the parent bodies of the NT source may be linked to the population of Halley-type comets. However, no model to date has been able to reproduce in detail the significant temporal variations in activity seen throughout the year.In this work we present observations of the NT meteoroid source made by the Canadian Meteor Orbit Radar (CMOR) between 2011 - 2015 and of the ST source obtained with the South Argentina Agile Meteor Radar (SAAMER) between 2011 - 2015. We use these results to define in detail the temporal and orbital element variations in the activity of both sources. We also present preliminary results from a model, in which we have identified 169 near-Earth objects that are potential contributors to the NT/ST meteoroid population at the current time. Furthermore, we integrate their orbits backward in time 25,000 years. For each potential parent body, we simulate 5 clones to span the range of possible parent body orbits as a function of time. From our initial epoch 25 ka, we eject 2000 test meteoroids per 100 years of sizes 30 μm to 1 mm per potential parent clone and examine the resulting dust trail intersecting the Earth to match the various temporally distinct portions of the NT/ST meteoroid complex. We find that while some of the observed features of both sources can be modeled as distinct past contributions from individual parent bodies, many major

  13. Agile Software Development

    ERIC Educational Resources Information Center

    Biju, Soly Mathew

    2008-01-01

    Many software development firms are now adopting the agile software development method. This method involves the customer at every level of software development, thus reducing the impact of change in the requirement at a later stage. In this article, the principles of the agile method for software development are explored and there is a focus on…

  14. METEORIC-HYDROTHERMAL SYSTEMS.

    USGS Publications Warehouse

    Criss, Robert E.; Taylor, Hugh P.

    1986-01-01

    This paper summarizes the salient characteristics of meteoric-hydrothermal systems, emphasing the isotopic systematics. Discussions of permeable-medium fluid dynamics and the geology and geochemistry of modern geothermal systems are also provided, because they are essential to any understanding of hydrothermal circulation. The main focus of the paper is on regions of ancient meteoric-hydrothermal activity, which give us information about the presently inaccessible, deep-level parts of modern geothermal systems. It is shown oxygen and hydrogen isotopes provide a powerful method to discover and map fossil hydrothermal systems and to investigate diverse associated aspects of rock alteration and ore deposition.

  15. Martian Meteor Crater

    NASA Technical Reports Server (NTRS)

    2004-01-01

    20 February 2004 This Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) image shows a fairly young meteor impact crater on Mars that is about the same size ( 1 kilometer; 0.62 miles) as the famous Meteor Crater in northern Arizona, U.S.A. Like the Arizona crater, boulders of ejected bedrock can be seen on the crater's ejecta blanket and in the crater itself. This crater is located in the Aethiopis region of Mars near 4.7oN, 224.1oW. Sunlight illuminates the scene from the lower left.

  16. The meteor complex of P/Encke

    NASA Astrophysics Data System (ADS)

    Porubcan, V.; Stohl, J.

    The Taurid meteor complex associated with P/Encke is studied on the basis of relevant photographic and radar orbits. Orbital characteristics, radiants and durations of the postperihelion showers are compared with corresponding theoretical values derived from the observations of the preperihelion Taurids. The validity of the proposed associations of minor showers with the Taurid complex and the total duration of its activity are evaluated and discussed. Some of the associated showers (the Northern and Southern Chi Orionids, Northern Piscids and Southern Arietids) are confirmed to be in fact, parts of the Taurid shower itself.

  17. Asteroids, Comets, Meteors 1991

    NASA Technical Reports Server (NTRS)

    Harris, Alan W. (Editor); Bowell, Edward (Editor)

    1992-01-01

    Papers from the conference are presented and cover the following topics with respect to asteroids, comets, and/or meteors: interplanetary dust, cometary atmospheres, atmospheric composition, comet tails, astronomical photometry, chemical composition, meteoroid showers, cometary nuclei, orbital resonance, orbital mechanics, emission spectra, radio astronomy, astronomical spectroscopy, photodissociation, micrometeoroids, cosmochemistry, and interstellar chemistry.

  18. Martian Meteor Ionization Layers

    NASA Technical Reports Server (NTRS)

    Grebowsky, J. M.; Pesnell, W. D.

    1999-01-01

    Small interplanetary grains bombard Mars, like all the solar system planets, and, like all the planets with atmospheres, meteoric ion and atom layers form in the upper atmosphere. We have developed a comprehensive one-dimensional model of the Martian meteoric ionization layer including a full chemical scheme. A persistent layer of magnesium ions should exist around an altitude of 70 km. Unlike the terrestrial case, where the metallic ions are formed via charge-exchange with the ambient ions, Mg(+) in the Martian atmosphere is produced by photoionization. Nevertheless, the predicted metal layer peak densities for Earth and Mars are similar. Diffusion solutions, such as those presented here, should be a good approximation of the metallic ions in regions where the magnetic field is negligible and may provide a significant contribution to the nightside ionosphere. The low ultraviolet absorption of the Martian atmosphere may make Mars an excellent laboratory in which to study meteoric ablation. Resonance lines not seen in the spectra of terrestrial meteors may be visible to a surface observatory in the Martian highlands.

  19. Anomalous meteors from the observations with super-isocon TV systems

    NASA Astrophysics Data System (ADS)

    Kozak, P.; Watanabe, J.; Sato, M.

    2014-07-01

    There is a range of both optical and radar observations of meteors the behavior of which essentially differs from the behavior of most meteors. In some cases such meteors cannot be explained in the frame of the classic physical theory of meteors, in other cases the meteors are just of rare type. First of all these are the meteors with true hyperbolic velocities. In spite of the fact that most of hyperbolic orbits are the results of calculation errors, the meteors with extremely high velocities appreciably exceeding the hyperbolic limit of 73 km/s exist and can be of interstellar origin [1--3]. Another very rare phenomenon describes the possible cluster structure of meteor streams, which could be connected with the ejection of the substance from the cometary nucleus shortly before collision of the particles with the Earth [4]. Among anomalies connected with the meteor motion in the atmosphere one can note, first of all, the ultra-high altitudes of meteor beginnings exceeding 130--140 km [5--7]. Some other observations point to the beginning heights of bright meteors from Leonid shower on altitudes near 200 km [8]. The classic physical theory of meteors cannot explain their radiation on such high altitudes because of low air density [9]. Recently the results of TV observations of meteors with diffusive and cloudy structure appeared [9,10]. The results of observations in which, according to author's opinion, the meteors have a few kilometers transverse jets [9--11] were presented as well. There are video frames with bright meteor obtained with high temporal resolution, where authors declared the radiation, which could be an effect of a spread directly of the shock wave [12]. During many years' double-station observations of meteors which have been carrying out at Astronomical Observatory of Kyiv National Taras Shevchenko University the ultra-sensitive TV transmitting tubes of super-isocon type were used [7]. Given type of the tube is one of the most sensitive in the

  20. Distributions of Orbital Elements for Meteoroids on Near-Parabolic Orbits According to Radar Observational Data

    NASA Technical Reports Server (NTRS)

    Kolomiyets, S. V.

    2011-01-01

    Some results of the International Heliophysical Year (IHY) Coordinated Investigation Program (CIP) number 65 Meteors in the Earth Atmosphere and Meteoroids in the Solar System are presented. The problem of hyperbolic and near-parabolic orbits is discussed. Some possibilities for the solution of this problem can be obtained from the radar observation of faint meteors. The limiting magnitude of the Kharkov, Ukraine, radar observation program in the 1970 s was +12, resulting in a very large number of meteors being detected. 250,000 orbits down to even fainter limiting magnitude were determined in the 1972-78 period in Kharkov (out of them 7,000 are hyperbolic). The hypothesis of hyperbolic meteors was confirmed. In some radar meteor observations 1 10% of meteors are hyperbolic meteors. Though the Advanced Meteor Orbit Radar (AMOR, New Zealand) and Canadian Meteor Orbit Radar (CMOR, Canada) have accumulated millions of meteor orbits, there are difficulties in comparing the radar observational data obtained from these three sites (New Zealand, Canada, Kharkov). A new global program International Space Weather Initiative (ISWI) has begun in 2010 (http://www.iswi-secretariat.org). Today it is necessary to create the unified radar catalogue of nearparabolic and hyperbolic meteor orbits in the framework of the ISWI, or any other different way, in collaboration of Ukraine, Canada, New Zealand, the USA and, possibly, Japan. Involvement of the Virtual Meteor Observatory (Netherlands) and Meteor Data Centre (Slovakia) is desirable too. International unified radar catalogue of near-parabolic and hyperbolic meteor orbits will aid to a major advance in our understanding of the ecology of meteoroids within the Solar System and beyond.

  1. Studies of Transient Meteor Activity

    NASA Technical Reports Server (NTRS)

    Jenniskens, Peter M. M.

    2002-01-01

    Meteoroids bombard Earth's atmosphere daily, but occasionally meteor rates increase to unusual high levels when Earth crosses the relatively fresh ejecta of comets. These transient events in meteor activity provide clues about the whereabouts of Earth-threatening long-period comets, the mechanisms of large-grain dust ejection from comets, and the particle composition and size distribution of the cometary ejecta. Observations of these transient events provide important insight in natural processes that determine the large grain dust environment of comets, in natural phenomena that were prevalent during the time of the origin of life, and in processes that determine the hazard of civilizations to large impacts and of man-made satellites to the periodic blizzard of small meteoroids. In this proposal, three tasks form a coherent program aimed at elucidating various aspects of meteor outbursts, with special reference to planetary astronomy and astrobiology. Task 1 was a ground-based effort to observe periods of transient meteor activity. This includes: (1) stereoscopic imaging of meteors during transient meteor events for measurements of particle size distribution, meteoroid orbital dispersions and fluxes; and (2) technical support for Global-MS-Net, a network of amateur-operated automatic counting stations for meteor reflections from commercial VHF radio and TV broadcasting stations, keeping a 24h vigil on the level of meteor activity for the detection of new meteor streams. Task 2 consisted of ground-based and satellite born spectroscopic observations of meteors and meteor trains during transient meteor events for measurements of elemental composition, the presence of organic matter in the meteoroids, and products generated by the interaction of the meteoroid with the atmosphere. Task 3 was an airborne effort to explore the 2000 Leonid meteor outbursts, which are anticipated to be the most significant of transient meteor activity events in the remainder of the

  2. [Fecal fermentation in meteorism].

    PubMed

    León-Barúa, R; Zapata-Solari, C

    1977-12-01

    An old test to investigate fecal fermentation was modified with the purpose of changing it from qualitative to quantitative. The modified test consists in placing in stove, at 37 degrees C for 24 hours, 5 grams of feces, suspended in water. The fermentable alimentary residues, present in the feces, suffer the action of bacteria, also there present, yielding gas that is collected and measured. Using the test, fecal fermentation was determined in 3 groups of individuals: a) 40 patients with meteorism that had persisted or improved only slightly or fairly with treatment; b) 28 apparently healthy subjects; and c) 6 patients with meteorism that had disappeared or become minimal with treatment. In the group of 28 apparently healthy subject, the obtained results varied from 0.1 to 1.1 ml gas/24 h., with a mean +/- s.d. of 0.55 +/- 0.29 ml. gas/24 h. When a distribution curve was made with the results obtained in the group of 40 patients with meteorism, these results separated into 2 subgroups: one subgroup with 28 patients, in whom results varied from 1.0 to 13.3 ml. gas/24 h., with a mean of 4.8 gas/24 h. (only) in 1 of these 28 patients a normal result of 1.0 ml. gas/24 h. was obtained, while in the remaining 27 patients results of 1.5 or more ml. gas/24 h. were obtained); and the other subgroup with 12 patients, in whom results varied from 0.0 to 0.9 ml. gas/24 h., with a mean of 0.29 ml. gas/24 h. Finally, in the group of 6 patients with successfully treated meteorism, results were from 0.1 to 0.9 ml. gas/24 h., with a mean of 0.4 ml. gas/24 h. The above mentioned results strongly suggest the existence of a relationship between meteorism and exagerated fecal fermentation. The nature of this relationship has not yet been completely clarified. However, the test used to determine fecal fermentation already promises to be very helpful for a better understanding and management of meteorism.

  3. Elemental abundance determinations for meteors by spectroscopy.

    NASA Technical Reports Server (NTRS)

    Harvey, G. A.

    1973-01-01

    Relative elemental abundance determinations for meteors by spectroscopy are discussed. Relative abundances of spectroscopically accessible elements of four major shower meteors and one sporadic meteor are presented. A sporadic meteor with dominant sodium radiation and an iron-deficient sporadic meteor are analyzed. Empirical and theoretical tests for self-absorption in optical meteor plasmas have been conducted. Both ionization and incomplete dissociation are found to severely deplete certain neutral atoms from meteor plasmas.

  4. Zhamanshin meteor crater

    NASA Technical Reports Server (NTRS)

    Florenskiy, P. V.; Dabizha, A. I.

    1987-01-01

    A historical survey and geographic, geologic and geophysical characteristics, the results of many years of study of the Zhamanshin meteor crater in the Northern Aral region, are reported. From this data the likely initial configuration and cause of formation of the crater are reconstructed. Petrographic and mineralogical analyses are given of the brecciated and remelted rocks, of the zhamanshinites and irgizite tektites in particular. The impact melting, dispersion and quenching processes resulting in tektite formation are discussed.

  5. Meteor signature interpretation

    SciTech Connect

    Canavan, G.H.

    1997-01-01

    Meteor signatures contain information about the constituents of space debris and present potential false alarms to early warnings systems. Better models could both extract the maximum scientific information possible and reduce their danger. Accurate predictions can be produced by models of modest complexity, which can be inverted to predict the sizes, compositions, and trajectories of object from their signatures for most objects of interest and concern.

  6. Optical fluxes and meteor properties of the camelopardalid meteor shower

    NASA Astrophysics Data System (ADS)

    Campbell-Brown, M. D.; Blaauw, R.; Kingery, A.

    2016-10-01

    Observations of the Camelopardalid meteor shower in May 2014 were obtained with six different sets of cameras, with limiting meteor magnitudes varying from -2M to +7M. Shower fluxes were calculated for each of the systems, from which the mass index of the shower was found to be 2.17 ± 0.04. Faint meteors in the shower were found to be stronger than average, ablating at lower altitudes than meteors at the same speed recorded with the same system, while the brightest meteors had higher ablation heights and were therefore weaker than typical meteors. These findings can be explained if large Camelopardalids are weak agglomerations of more refractory grains, which are easily disrupted in space and keep the shower supplied with small material and depleted in large material.

  7. An antenna, a radio and a microprocessor: which kinds of observation are possible in meteor radio astronomy?

    NASA Astrophysics Data System (ADS)

    Barbieri, L.

    2016-01-01

    Radio meteors are usually investigated by professional radars. Amateur astronomers cannot have transmitters, so usually they can only listen to sounds generated by a radio tuned to a TV or military transmitter. Until recently, this kind of observation has not produced good data. The experience of "RAMBo" (Radar Astrofilo Meteorico Bolognese) shows which data can be extracted from an amateur meteor scatter observatory and the results which can be achieved.

  8. Meteor head echo characteristics observed with MAARSY in the polar region

    NASA Astrophysics Data System (ADS)

    Schult, Carsten; Stober, Gunter; Chau, Jorge L.

    2016-04-01

    The Middle Atmosphere Alomar Radar System (MAARSY, 53.5 MHz), on the North Norwegian island Andoya (69.30° N, 16.04° E) , is the only high power large aperture (HPLA) radar system with interferometric capabilities providing daily meteor head echo observations since November 2013. Meanwhile, the data set of meteor head echoes contains over one million events with a perfect daily and seasonal coverage of the four northern hemisphere sporadic sources. Although, the North Apex meteor source dominates the observation by far (more than 40%), the statistic is large enough for a comparison of the observational meteor parameters for all sporadic sources. Furthermore, due to the large spread of the antenna gain of the HPLA radar system in combination with the interferometric solutions, the observation area can be divided into high and low sensitive regions with different collecting sizes. This separation is equivalent with a measurement of various radar systems with different beam characteristics, observing at the same time and geographical location. This helps answering question on the impact of the radar specifications on the meteor head echo measurements.

  9. Light curves of faint meteors

    NASA Astrophysics Data System (ADS)

    Koten, Pavel; Borovička, Jiří

    2001-11-01

    The results of the light curves analysis of 234 meteors observed and recorded within the double-station image intensifier observations at the Ondřejov observatory are presented. Double-station observations allow to compute the meteor trajectory in the solar system and in the atmosphere as well as to determinate the absolute magnitude of meteor and its mass. Light curves and heights data of all major meteor showers - Lyrids, η-Aquarids, Perseids, Orionids, Leonids, Geminids as well as many sporadic meteors - were analysed. The differences between individual showers were found, e.g. Perseids appear to be more compact than Leonids. There is also difference between 1998 and 1999 Leonids. This suggests different composition or structure of parent bodies. Our data show that the beginning heights of Perseids, Orionids and Leonids are weakly dependent on meteor mass, although the dust-ball theory assumes they should be mass independent.

  10. Meteors in Australian Aboriginal Dreamings

    NASA Astrophysics Data System (ADS)

    Hamacher, Duane W.; Norris, Ray P.

    2010-06-01

    We present a comprehensive analysis of Australian Aboriginal accounts of meteors. The data used were taken from anthropological and ethnographic literature describing oral traditions, ceremonies, and Dreamings of 97 Aboriginal groups representing all states of modern Australia. This revealed common themes in the way meteors were viewed between Aboriginal groups, focusing on supernatural events, death, omens, and war. The presence of such themes around Australia was probably due to the unpredictable nature of meteors in an otherwise well-ordered cosmos.

  11. Dynamical Model for the Zodiacal Cloud and Sporadic Meteors

    NASA Astrophysics Data System (ADS)

    Nesvorný, David; Janches, Diego; Vokrouhlický, David; Pokorný, Petr; Bottke, William F.; Jenniskens, Peter

    2011-12-01

    The solar system is dusty, and would become dustier over time as asteroids collide and comets disintegrate, except that small debris particles in interplanetary space do not last long. They can be ejected from the solar system by Jupiter, thermally destroyed near the Sun, or physically disrupted by collisions. Also, some are swept by the Earth (and other planets), producing meteors. Here we develop a dynamical model for the solar system meteoroids and use it to explain meteor radar observations. We find that the Jupiter Family Comets (JFCs) are the main source of the prominent concentrations of meteors arriving at the Earth from the helion and antihelion directions. To match the radiant and orbit distributions, as measured by the Canadian Meteor Orbit Radar (CMOR) and Advanced Meteor Orbit Radar (AMOR), our model implies that comets, and JFCs in particular, must frequently disintegrate when reaching orbits with low perihelion distance. Also, the collisional lifetimes of millimeter particles may be longer (gsim 105 yr at 1 AU) than postulated in the standard collisional models (~104 yr at 1 AU), perhaps because these chondrule-sized meteoroids are stronger than thought before. Using observations of the Infrared Astronomical Satellite to calibrate the model, we find that the total cross section and mass of small meteoroids in the inner solar system are (1.7-3.5) × 1011 km2 and ~4 × 1019 g, respectively, in a good agreement with previous studies. The mass input required to keep the zodiacal cloud in a steady state is estimated to be ~104-105 kg s-1. The input is up to ~10 times larger than found previously, mainly because particles released closer to the Sun have shorter collisional lifetimes and need to be supplied at a faster rate. The total mass accreted by the Earth in particles between diameters D = 5 μm and 1 cm is found to be ~15,000 tons yr-1 (factor of two uncertainty), which is a large share of the accretion flux measured by the Long Term Duration

  12. Dynamical Model for the Zodiacal Cloud and Sporadic Meteors

    NASA Technical Reports Server (NTRS)

    Nesvorny, David; Janches, Diego; Vokrouhlicky, David; Pokorny, Petr; Bottke, William F.; Jenniskens, Peter

    2011-01-01

    The solar system is dusty, and would become dustier over time as asteroids collide and comets disintegrate, except that small debris particles in interplanetary space do not last long. They can be ejected from the solar system by Jupiter, thermally destroyed near the Sun, or physically disrupted by collisions. Also, some are swept by the Earth (and other planets), producing meteors. Here we develop a dynamical model for the solar system meteoroids and use it to explain meteor radar observations. We find that the Jupiter Family Comets (JFCs) are the main source of the prominent concentrations of meteors arriving to the Earth from the helion and antihelion directions. To match the radiant and orbit distributions, as measured by the Canadian Meteor Orbit Radar (CMOR) and Advanced Meteor Orbit Radar (AMOR), our model implies that comets, and JFCs in particular, must frequently disintegrate when reaching orbits with low perihelion distance. Also, the collisional lifetimes of millimeter particles may be longer (approx. > 10(exp 5) yr at 1 AU) than postulated in the standard collisional models (approx 10(exp 4) yr at 1 AU), perhaps because these chondrule-sized meteoroids are stronger than thought before. Using observations of the Infrared Astronomical Satellite (IRAS) to calibrate the model, we find that the total cross section and mass of small meteoroids in the inner solar system are (1.7-3.5) 10(exp 11) sq km and approx. 4 10(exp 19) g, respectively, in a good agreement with previous studies. The mass input required to keep the Zodiacal Cloud (ZC) in a steady state is estimated to be approx. 10(exp 4)-10(exp 5) kg/s. The input is up to approx 10 times larger than found previously, mainly because particles released closer to the Sun have shorter collisional lifetimes, and need to be supplied at a faster rate. The total mass accreted by the Earth in particles between diameters D = 5 micron and 1 cm is found to be approx 15,000 tons/yr (factor of 2 uncertainty), which is

  13. Radar Performance Improvement. Angle Tracking Modification to Fire Control Radar System for Space Shuttle Rendezvous

    NASA Technical Reports Server (NTRS)

    Little, G. R.

    1976-01-01

    The AN/APQ-153 fire control radar modified to provide angle tracking was evaluated for improved performance. The frequency agile modifications are discussed along with the range-rate improvement modifications, and the radar to computer interface. A parametric design and comparison of noncoherent and coherent radar systems are presented. It is shown that the shuttle rendezvous range and range-rate requirements can be made by a Ku-Band noncoherent pulse radar.

  14. Dependences of Ratio of the Luminosity to Ionization on Velocity and Chemical Composition of Meteors

    NASA Technical Reports Server (NTRS)

    Narziev, M.

    2011-01-01

    On the bases of results simultaneous photographic and radio echo observations, the results complex radar and television observations of meteors and also results of laboratory modeling of processes of a luminescence and ionization, correlation between of luminous intensity Ip to linear electronic density q from of velocities and chemical structure are investigated. It is received that by increasing value of velocities of meteors and decrease of nuclear weight of substance of particles, lg Ip/q decreased more than one order.

  15. Meteor Beliefs Project: Meteoric references in Ovid's Metamorphoses

    NASA Astrophysics Data System (ADS)

    Gheorghe, A. D.; McBeath, A.

    2003-10-01

    Three sections of Ovid's Metamorphoses are examined, providing further information on meteoric beliefs in ancient Roman times. These include meteoric imagery among the portents associated with the death of Julius Caesar, which we mentioned previously from the works of William Shakespeare (McBeath and Gheorghe, 2003b).

  16. James Joule and meteors

    NASA Astrophysics Data System (ADS)

    Hughes, David W.

    1989 was the hundredth anniversary of the death of James Prescott Joule, the Prescott being his mother's family name and the Joule, rhyming with cool, originating from the Derbyshire village of Youlgreave. Joule is rightly famous for his experimental efforts to establish the law of conservation of energy, and for the fact that J, the symbol known as the mechanical equivalent of heat, is named after him. Astronomically his "light has been hidden under a bushel". James Joule had a major influence on the physics of meteors.

  17. Hard- and software problems of spaced meteor observations by optical electronics

    NASA Technical Reports Server (NTRS)

    Shafiev, R. I.; Mukhamednazarov, S.; Ataev, A. SH.

    1987-01-01

    An optical electronic facility is being used for meteor observations along with meteor radars and astronomical TV. The main parts of the facility are cameras using UM-92 optical electronic image tubes. The three cascade optical electronic image tube with magnetic focusing has a 40 mm cathode and resolution in the center of up to 30 pairs of lines/mm. The photocathode is of a multislit S-20 type. For meteor spectra observations, replica gratings of 200 and 300 lines/mm are used as the dispersive element.

  18. A Quantitative Kinetic Theory of Meteor Plasma Formation

    NASA Astrophysics Data System (ADS)

    Dimant, Yakov; Oppenheim, Meers

    2014-10-01

    Every second millions of small meteoroids hit the Earth from space, the vast majority too small to observe visually. Radars easily detect the plasma they generate and use the data they gather to characterize the meteoroids and the atmosphere in which they disintegrate. These diagnostics requires a detailed quantitative understanding of the formation of the meteor plasma and how it interacts with the Earth's atmosphere. Meteors become detectable to radars after they heat due to collisions with atmospheric molecules sufficiently that they begin to sublimate. The sublimated material then collides into atmospheric molecules and forms plasma around and behind the meteoroid. Reflection of radar pulses from the plasma around the descending meteoroid produces a localized signal called a head echo. This research applies kinetic theory to show that the meteoroid plasma develops over a length-scale close to the ion mean free path with a non-Maxwellian velocity distribution. This analytical model will serve as a basis for quantitative interpretation of the head echo radar measurements, the ionization efficiency (called the Beta parameter), and should help us calculate meteoroid and atmosphere parameters from radar head-echo observations. Work supported by NSF Grant AGS-1244842.

  19. An agile implementation of SCRUM

    NASA Astrophysics Data System (ADS)

    Gannon, Michele

    Is Agile a way to cut corners? To some, the use of an Agile Software Development Methodology has a negative connotation - “ Oh, you're just not producing any documentation” . So can a team with no experience in Agile successfully implement and use SCRUM?

  20. Strategic agility for nursing leadership.

    PubMed

    Shirey, Maria R

    2015-06-01

    This department highlights change management strategies that may be successful in strategically planning and executing organizational change. In this article, the author discusses strategic agility as an important leadership competency and offers approaches for incorporating strategic agility in healthcare systems. A strategic agility checklist and infrastructure-building approach are presented. PMID:26010278

  1. Strategic agility for nursing leadership.

    PubMed

    Shirey, Maria R

    2015-06-01

    This department highlights change management strategies that may be successful in strategically planning and executing organizational change. In this article, the author discusses strategic agility as an important leadership competency and offers approaches for incorporating strategic agility in healthcare systems. A strategic agility checklist and infrastructure-building approach are presented.

  2. Meteor fireball sounds identified

    NASA Technical Reports Server (NTRS)

    Keay, Colin

    1992-01-01

    Sounds heard simultaneously with the flight of large meteor fireballs are electrical in origin. Confirmation that Extra/Very Low Frequency (ELF/VLF) electromagnetic radiation is produced by the fireball was obtained by Japanese researchers. Although the generation mechanism is not fully understood, studies of the Meteorite Observation and Recovery Project (MORP) and other fireball data indicate that interaction with the atmosphere is definitely responsible and the cut-off magnitude of -9 found for sustained electrophonic sounds is supported by theory. Brief bursts of ELF/VLF radiation may accompany flares or explosions of smaller fireballs, producing transient sounds near favorably placed observers. Laboratory studies show that mundane physical objects can respond to electrical excitation and produce audible sounds. Reports of electrophonic sounds should no longer be discarded. A catalog of over 300 reports relating to electrophonic phenomena associated with meteor fireballs, aurorae, and lightning was assembled. Many other reports have been cataloged in Russian. These may assist the full solution of the similar long-standing and contentious mystery of audible auroral displays.

  3. Asteroids, Comets, Meteors 2014

    NASA Astrophysics Data System (ADS)

    Muinonen, K.; Penttilä, A.; Granvik, M.; Virkki, A.; Fedorets, G.; Wilkman, O.; Kohout, T.

    2014-08-01

    Asteroids, Comets, Meteors focuses on the research of small Solar System bodies. Small bodies are the key to understanding the formation and evolution of the Solar System, carrying signals from pre-solar times. Understanding the evolution of the Solar System helps unveil the evolution of extrasolar planetary systems. Societally, small bodies will be important future resources of minerals. The near-Earth population of small bodies continues to pose an impact hazard, whether it be small pieces of falling meteorites or larger asteroids or cometary nuclei capable of causing global environmental effects. The conference series entitled ''Asteroids, Comets, Meteors'' constitutes the leading international series in the field of small Solar System bodies. The first three conferences took place in Uppsala, Sweden in 1983, 1985, and 1989. The conference is now returning to Nordic countries after a quarter of a century. After the Uppsala conferences, the conference has taken place in Flagstaff, Arizona, U.S.A. in 1991, Belgirate, Italy in 1993, Paris, France in 1996, Ithaca, New York, U.S.A. in 1999, in Berlin, Germany in 2002, in Rio de Janeiro, Brazil in 2005, in Baltimore, Maryland, U.S.A. in 2008, and in Niigata, Japan in 2012. ACM in Helsinki, Finland in 2014 will be the 12th conference in the series.

  4. Computational Physics of Small Meteors

    NASA Astrophysics Data System (ADS)

    Surzhikov, S. T.

    2015-10-01

    This paper is dedicated to application of the modern computational aero physical models, which were developed for mathematical modeling of aerothermodynamics and radiative gasdynamics of space vehicles, for investigation of meteoric phenomena. Short analysis of modern problems of meteoric physics is presented. The typical chemical compositions of meteoric bodies are discussed. Considerable attention is given to investigation of the non-equilibrium physical-chemical processes accompanying a meteor with relatively small size at altitude of 70 km, in the conditions, when the vibrational relaxation zone exceeds the size of meteoric body. Two-dimensional numerical simulation radiative gas dynamics model of physically and chemically nonequilibrium flow field around the meteoroid bodies entering Earth atmosphere is presented.

  5. Creating IT agility.

    PubMed

    Glaser, John

    2008-04-01

    Seven steps healthcare organizations can take to improve IT agility are: Pay attention to the capabilities of IT applications. Establish short project phases. Stage the release of capital and new IT positions. Cross-train IT staff. Adopt technology standards. Shorten IT plan time horizons. Align IT with organizational strategies and priorities.

  6. SAR imagery using chaotic carrier frequency agility pulses

    NASA Astrophysics Data System (ADS)

    Xu, Xiaojian; Feng, Xiangzhi

    2011-06-01

    Synthetic aperture radar (SAR) systems are getting more and more applications in both civilian and military remote sensing missions. With the increasing deployment of electronic countermeasures (ECM) on modern battlefields, SAR encounters more and more interference jamming signals. The ECM jamming signals cause the SAR system to receive and process erroneous information which results in severe degradations in the output SAR images and/or formation of phony images of nonexistent targets. As a consequence, development of the electronic counter-countermeasures (ECCM) capability becomes one of the key problems in SAR system design. This paper develops radar signaling strategies and algorithms that enhance the ability of synthetic aperture radar to image targets under conditions of electronic jamming. The concept of SAR using chaotic carrier frequency agility pulses (CCFAP-SAR) is first proposed. Then the imaging procedure for CCFAP-SAR is discussed in detail. The ECCM performance of CCFAP-SAR for both depressive noise jamming and deceptive repeat jamming is analyzed. The impact of the carrier frequency agility range on the image quality of CCFAP-SAR is also studied. Simulation results demonstrate that, with adequate agility range of the carrier frequency, the proposed CCFAP-SAR performs as well as conventional radar with linear frequency modulation (LFM) waveform in image quality and slightly better in anti-noise depressive jamming; while performs very well in anti-deception jamming which cannot be rejected by LFM-SAR.

  7. Aircraft radar antennas

    NASA Astrophysics Data System (ADS)

    Schrank, Helmut E.

    1987-04-01

    Many changes have taken place in airborne radar antennas since their beginnings over forty years ago. A brief historical review of the advances in technology is presented, from mechanically scanned reflectors to modern multiple function phased arrays. However, emphasis is not on history but on the state-of-the-art technology and trends for future airborne radar systems. The status of rotating surveillance antennas is illustrated by the AN/APY-1 Airborne Warning and Control System (AWACS) slotted waveguide array, which achieved a significant breakthrough in sidelobe suppression. Gimballed flat plate arrays in nose radomes are typified by the AN/APG-66 (F-16) antenna. Multifunction phased arrays are presented by the Electronically Agile Radar (EAR) antenna, which has achieved significant advances in performance versatility and reliability. Trends toward active aperture, adaptive, and digital beamforming arrays are briefly discussed. Antennas for future aircraft radar systems must provide multiple functions in less aperture space, and must perform more reliably.

  8. The Chelyabinsk meteor

    NASA Astrophysics Data System (ADS)

    Popova, O.; Jenniskens, P.; Shuvalov, V.; Emel'yanenko, V.; Rybnov, Y.; Kharlamov, V.; Kartashova, A.; Biryukov, E.; Khaibrakhmanov, S.

    2014-07-01

    A review is given about what was learned about the 0.5-Mt Chelyabinsk airburst of 15 February 2013 by field studies, the analysis of recovered meteorites, and numerical models of meteoroid fragmentation and airburst propagation. Previous events with comparable or larger energy in recent times include only the 0.5-Mt -sized 3 August 1963 meteor over the south Atlantic, for which only an infrasound signal was recorded, and the famous Tunguska impact of 1908. Estimates of the initial kinetic energy of the Tunguska impact range from 3 to 50 Mt, due to the lack of good observations at the time. The Chelyabinsk event is much better documented than both, and provides a unique opportunity to calibrate the different approaches used to model meteoroid entry and calculate the damaging effects of a shock wave from a large meteoroid impact. A better understanding of what happened might help future impact hazard mitigation efforts by calibrating models of what might happen under somewhat different circumstances. The initial kinetic energy is estimated from infrasonic signals and the fireball's lightcurve, as well as the extent of the glass damage on the ground. Analysis of video observations of the fireball and the shadow movements provided an impact trajectory and a record of the meteor lightcurve, which describes how that energy was deposited in the atmosphere. Ablation and fragmentation scenarios determine the success of attempts to reproduce the observed meteor lightcurve and deceleration profile by numerical modeling. There was almost no deceleration until peak brightness. Meteoroid fragmentation occurred in different forms, some part of the initial mass broke in well separated fragments, the surviving fragments falling on the ground as meteorites. The specific conditions during energy deposition determined the fraction of surviving mass. The extent of the glass damage was mapped by visiting over 50 villages in the area. A number of numerical simulations were conducted that

  9. MST radar detection of middle atmosphere tides

    NASA Technical Reports Server (NTRS)

    Forbes, J. M.

    1983-01-01

    Meteorological and dynamical requirements pertaining to the specification of middle atmosphere tides by the MST radar technique are outlined. Major issues addressed include: (1) the extraction of tidal information from measurements covering a fraction of a day; (2) the ramifications of transient effects (tidal variability) on the determination and interpretation of tides; (3) required temporal and spatial resolutions and; (4) global distributions of MST radars, so as to complement existing MST, meteor wind, and partial reflection drift radar locations.

  10. Identification of Optical Component of North Toroidal Source of Sporadic Meteors and its Origin

    NASA Technical Reports Server (NTRS)

    Hashimoto, T.; Watanabe, J.; Sato, M.; Ishiguro, M.

    2011-01-01

    We succeeded to identify the North Toroidal source by optical observations performed by the SonotaCo Network, which is a TV observation network coordinated by Japanese amateurs. This source has been known only for radar observations until now. The orbits of the optical meteors in the North Toroidal source are relatively large eccentricity and semi-major axis, compared with those of the radar meteors. In this paper, we report the characteristics of this North Toroidal source detected by optical observations, and discuss the possible origin and evolution of this source.

  11. What do we see as ANT, Apex and Toroidal sources? - What meteors are, where meteors came from, where meteoroids are going

    NASA Astrophysics Data System (ADS)

    Koseki, Masahiro

    2015-10-01

    We found that the observabilities of meteors depend strongly on meteor velocity; the ratio of the number of CCD to photographic meteors is expressed as a quadratic function of the velocity, and the observability for radar observations has a clear peak around V_g=30 km/s. If we do not compensate for the observability, we are under the impression that radar observations contribute most to the Toroidal activity, CCD observations record a huge number of the Apex meteors, and photographic meteors concentrate on the ANT area. We assume that the observed number against the velocity shows roughly the observability for each observational technique and get more plausible results: in first place in radar observations is the Apex source and in optical observations ANT, while the Toroidal source is not so impressive. We calculated the radiants of 3212 comets and 1533 PHAs (potentially hazardous asteroids), finding 193 radiants of periodic comets, 1013 radiants of non-periodic comets and 3018 radiants of PHAs. Comparison of predicted to observed radiants reveals a very interesting fact: the contribution of the periodic comets to sporadic meteor activities is small, though we have clear recollections of meteor showers made up by a substantial number of massive meteoroids. It is clear many meteoroids from periodic comets meet Earth with low velocity and do not radiate enough light to be visible. Both predicted and observed radiant distributions clearly separate into two regions except for radiant areas relating to periodic comets. It is suggested that the Apex source is descended from non-periodic comets, ANT from asteroid kinsfolk and the Toroidal source is accumulated by older particles near Earth's orbit from both comets and asteroids.

  12. Catalogue of representative meteor spectra

    NASA Astrophysics Data System (ADS)

    Vojáček, V.; Borovička, J.; Koten, P.; Spurný, P.; Štork, R.

    2015-08-01

    Aims: We present a library of low-resolution meteor spectra that includes sporadic meteors, members of minor meteor showers, and major meteor showers. These meteors are in the magnitude range from +2 to -3, corresponding to meteoroid sizes from 1 mm to 10 mm. Methods: Parallel double-station video observations allowed us to compute heliocentric orbits for all meteors. Most observations were performed during the periods of activity of major meteor showers in the years between 2006 and 2012. Spectra are classified according to relative intensities of the low-temperature emission lines of Mg, Na, and Fe. Results: Shower meteors were found to be of normal composition, except for Southern δ Aquariids and some members of the Geminid shower, neither of which have Na in the meteor spectra. Variations in Na content are typical for the Geminid shower. Three populations of Na-free mereoroids were identified. The first population are iron meteorites, which have an asteroidal-chondritic origin, but one meteoroid with low perihelion (0.11 AU) was found among the iron meteorites. The second population were Sun-approaching meteoroids in which sodium is depleted by thermal desorption. The third population were Na-free meteoroids of cometary origin. Long exposure to cosmic rays on the surface of comets in the Oort cloud and disintegration of this crust might be the origin of this population of meteoroids. Spectra (Figs. 17-30) are only, Tables 4-6 are also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/580/A67

  13. MU head echo observations of the 2010 Geminids: radiant, orbit, and meteor flux observing biases

    NASA Astrophysics Data System (ADS)

    Kero, J.; Szasz, C.; Nakamura, T.

    2013-03-01

    We report Geminid meteor head echo observations with the high-power large-aperture (HPLA) Shigaraki middle and upper atmosphere (MU) radar in Japan (34.85° N, 136.10° E). The MU radar observation campaign was conducted from 13 December 2010, 08:00 UTC to 15 December, 20:00 UTC and resulted in 48 h of radar data. A total of ~ 270 Geminids were observed among ~ 8800 meteor head echoes with precisely determined orbits. The Geminid head echo activity is consistent with an earlier peak than the visual Geminid activity determined by the International Meteor Organization (IMO). The observed flux of Geminids is a factor of ~ 3 lower than the previously reported flux of the 2009 Orionids measured with an identical MU~radar setup. We use the observed flux ratio to discuss the relation between the head echo mass-velocity selection effect, the mass distribution indices of meteor showers and the mass threshold of the MU radar.

  14. Artificial meteor test towards: On-demand meteor shower

    NASA Astrophysics Data System (ADS)

    Abe, S.; Okajima, L.; Sahara, H.; Watanabe, T.; Nojiri, Y.; Nishizono, T.

    2016-01-01

    An arc-heated wind tunnel is widely used for ground-based experiments to simulate environments of the planetary atmospheric entry under hypersonic and high-temperature conditions. In order to understand details of a meteor ablation such as temperature, composition ratio and fragmentation processes, the artificial meteor test was carried out using a JAXA/ISAS arc-heated wind tunnel. High-heating rate around 30 MW/m2 and High-enthalpy conditions, 10000 K arc-heated flow at velocity around 6 km/s were provided. Newly developed artificial metallic meteoroids and real meteorites such as Chelyabinsk were used for the ablation test. The data obtained by near-ultraviolet and visible spectrograph (200 and 1100nm) and high-speed camera (50 μs) have been examined to develop more efficient artificial meteor materials. We will test artificial meteors from a small satellite in 2018.

  15. Recent meteor observing activities in Japan

    NASA Astrophysics Data System (ADS)

    Yamamoto, M.

    2005-02-01

    The meteor train observation (METRO) campaign is described as an example of recent meteor observing activity in Japan. Other topics of meteor observing activities in Japan, including Ham-band radio meteor observation, the ``Japan Fireball Network'', the automatic video-capture software ``UFOCapture'', and the Astro-classroom programme are also briefly introduced.

  16. THE RETURN OF THE ANDROMEDIDS METEOR SHOWER

    SciTech Connect

    Wiegert, Paul A.; Brown, Peter G.; Weryk, Robert J.; Wong, Daniel K.

    2013-03-15

    The Andromedid meteor shower underwent spectacular outbursts in 1872 and 1885, producing thousands of visual meteors per hour and described as ''stars fell like rain'' in Chinese records of the time. The shower originates from comet 3D/Biela whose disintegration in the mid-1800's is linked to the outbursts, but the shower has been weak or absent since the late 19th century. This shower returned in 2011 December with a zenithal hourly rate of approximately 50, the strongest return in over a hundred years. Some 122 probable Andromedid orbits were detected by the Canadian Meteor Orbit Radar while one possible brighter Andromedid member was detected by the Southern Ontario Meteor Network and several single station possible Andromedids by the Canadian Automated Meteor Observatory. The shower outburst occurred during 2011 December 3-5. The radiant at R.A. +18 Degree-Sign and decl. +56 Degree-Sign is typical of the ''classical'' Andromedids of the early 1800s, whose radiant was actually in Cassiopeia. Numerical simulations of the shower were necessary to identify it with the Andromedids, as the observed radiant differs markedly from the current radiant associated with that shower. The shower's orbital elements indicate that the material involved was released before 3D/Biela's breakup prior to 1846. The observed shower in 2011 had a slow geocentric speed (V{sub G} = 16 km s{sup -1}) and was comprised of small particles: the mean measured mass from the radar is {approx}5 Multiplication-Sign 10{sup -7} kg, corresponding to radii of 0.5 mm at a bulk density of 1000 kg m{sup -3}. Numerical simulations of the parent comet indicate that the meteoroids of the 2011 return of the Andromedids shower were primarily ejected during 3D/Biela's 1649 perihelion passage. The orbital characteristics, radiant, and timing as well as the absence of large particles in the streamlet are all broadly consistent with simulations. However, simulations of the 1649 perihelion passage necessitate going

  17. Perspectives on Agile Coaching

    NASA Astrophysics Data System (ADS)

    Fraser, Steven; Lundh, Erik; Davies, Rachel; Eckstein, Jutta; Larsen, Diana; Vilkki, Kati

    There are many perspectives to agile coaching including: growing coaching expertise, selecting the appropriate coach for your context; and eva luating value. A coach is often an itinerant who may observe, mentor, negotiate, influence, lead, and/or architect everything from team organization to system architecture. With roots in diverse fields ranging from technology to sociology coaches have differing motivations and experience bases. This panel will bring together coaches to debate and discuss various perspectives on agile coaching. Some of the questions to be addressed will include: What are the skills required for effective coaching? What should be the expectations for teams or individu als being coached? Should coaches be: a corporate resource (internal team of consultants working with multiple internal teams); an integral part of a specific team; or external contractors? How should coaches exercise influence and au thority? How should management assess the value of a coaching engagement? Do you have what it takes to be a coach? - This panel will bring together sea soned agile coaches to offer their experience and advice on how to be the best you can be!

  18. Meteor Beliefs Project: Seven years and counting

    NASA Astrophysics Data System (ADS)

    McBeath, A.; Drobnock, G. J.; Gheorghe, A. D.

    2010-04-01

    The Meteor Beliefs Project's seventh anniversary is celebrated with an eclectic mixture of meteor beliefs from the 1799 Leonids in Britain, the folkloric link between meteors and wishing in some Anglo-American sources, how a meteoric omen came to feature in Nathaniel Hawthorne's 1850 novel The Scarlet Letter, and a humorous item from the satirical magazine Punch in 1861, all helping to show how meteor beliefs can be transformed by different parts of society.

  19. On the interaction meteor complex

    NASA Astrophysics Data System (ADS)

    Rajchl, J.

    An approach to the problem of a meteoric complex called the interaction meteor complex (IMC) is applied and discussed, generalizing the idea of the interaction layer (Rajchl 1969). The role of an extended interaction of meteoroids is emphasized, both with planet surfaces and/or their satellites and with planet atmospheres, elastic or inelastic in form. The dissipation and related formative aspect are joined in one complex and compared with a topological compact. Examples of these types of interaction are presented.

  20. Automated Optical Meteor Fluxes and Preliminary Results of Major Showers

    NASA Technical Reports Server (NTRS)

    Blaauw, R.; Campbell-Brown, M.; Cooke, W.; Kingery, A.; Weryk, R.; Gill, J.

    2014-01-01

    active shower or sporadic source radiant. The flux per height interval is calculated and summed to obtain the total meteor flux. Both single station and double station fluxes are currently found daily. Geminid fluxes on the peak night in 2012 (12-14-2012) were 0.058 meteors/km2/hr as found with double-station meteors and 0.057 meteors/ km2/hr as found with single-station meteors, to a limiting magnitude of +6.5. Both of those numbers are in agreement with the well-calibrated fluxes from the Canadian Meteor Orbit Radar. Along with flux algorithms and initial flux results, presented will be results from the first 18 months of operation, covering 3,000+ meteoroid orbits.

  1. Structure and sources of the sporadic meteor background from video observations

    NASA Astrophysics Data System (ADS)

    Jakšová, Ivana; Porubčan, Vladimír; Klačka, Jozef

    2015-10-01

    We investigate and discuss the structure of the sporadic meteor background population in the near-Earth space based on video meteor orbits from the SonotaCo database (SonotaCo 2009, WGN, 37, 55). The selection of the shower meteors was done by the Southworth-Hawkins streams-search criterion (Southworth & Hawkins 1963, Smithson. Contr. Astrophys., 7, 261). Of a total of 117786 orbits, 69.34% were assigned to sporadic background meteors. Our analysis revealed all the known sporadic sources, such as the dominant apex source which is splitting into the northern and southern branch. Part of a denser ring structure about the apex source connecting the antihelion and north toroidal sources is also evident. We showed that the annual activity of the apex source is similar to the annual variation in activity of the whole sporadic background. The antihelion source exhibits a very broad maximum from July until January and the north toroidal source shows three maxima similar to the radar observations by the Canadian Meteor Orbit Radar (CMOR). Potential parent bodies of the sporadic population were searched for by comparison of the distributions of the orbital elements of sporadic meteors, minor planets and comets.

  2. Meteors and showers a millennium ago

    NASA Astrophysics Data System (ADS)

    Ahn, Sang-Hyeon

    2003-08-01

    Meteors can be classified into either sporadic meteors or showery meteors. We compile the meteor records in the astronomical archives in the chronicle of the Koryo dynasty (918-1392), and investigate the spatial distribution of meteor streams along the orbit of the Earth from the 10th to the 14th century. We see that meteors from meteor streams signalize themselves over noisy sporadic meteors, and that the seasonal activity of sporadic meteors is apparently regular. We discover the presence of a few meteor streams by analysing about 700 meteors in the Koryo period. We also compile the records of meteor showers and storms in the chronicles of Korea, Japan, China, Arabia and Europe, and compare their appearance dates with those of showers obtained in our analysis, as well as with the modern observations. We confirm that the three sets of data are in agreement with each other. The representative meteor showers are the Perseids, the Leonids, and the η Aquarids/Orionids pair formed by Halley's comet. The other weak or relic meteor streams are also observable but uncertain. Hence we witness the regularity of meteor activity, which is seen to persist for a millennium.

  3. Dispersion of meteor trails in the geomagnetic field.

    PubMed

    Robson, R E

    2001-02-01

    A meteor trail is modeled by a long column of weakly ionized plasma, whose dispersion is controlled by the geomagnetic field and the requirement to maintain effective space charge neutrality. First we consider scattering of a radar signal from an underdense trail and derive an expression for the amplitude of the backscattered signal as a function of time. Then, starting from the basic momentum balance equations for electrons and ions in a partially ionized plasma, we require divergences of ion and electron fluxes to be equal, plus assume equality of the flux components along the magnetic field direction. The analysis is really applicable to a whole range of plasma problems, although we focus upon meteor trails for now. It is found that charged particle densities satisfy a diffusion equation and we obtain an expression for the ambipolar diffusion tensor and expressions for the ambipolar electric field, valid for arbitrary relative orientations of the magnetic field and meteor trail axis. Results are somewhat different from previous analyses in the meteor literature.

  4. Barringer Meteor Crater, Arizona

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Barringer Crater, also known as 'Meteor Crater,' is a 1,300-meter (0.8 mile) diameter, 174-meter (570-feet) deep hole in the flat-lying desert sandstones 30 kilometers (18.6 miles) west of Winslow, Arizona. Since the 1890s geologic studies here played a leading role in developing an understanding of impact processes on the Earth, the moon and elsewhere in the solar system.

    This view was acquired by the Landsat 4 satellite on December 14, 1982. It shows the crater much as a lunar crater might appear through a telescope. Morning sun illumination is from the southeast (lower right). The prominent gully meandering across the scene is known as Canyon Diablo. It drains northward toward the Little Colorado River and eventually to the Grand Canyon. The Interstate 40 highway crosses and nearly parallels the northern edge of the scene.

    The ejecta blanket around the crater appears somewhat lighter than the surrounding terrain, perhaps in part due to its altered mineralogic content. However, foot traffic at this interesting site may have scarred and lightened the terrain too. Also, the roughened surface here catches the sunlight on the southerly slopes and protects a highly reflective patchy snow cover in shaded northerly slopes, further lightening the terrain as viewed from space on this date.

  5. Penn State Radar Systems: Implementation and Observations

    NASA Astrophysics Data System (ADS)

    Urbina, J. V.; Seal, R.; Sorbello, R.; Kuyeng, K.; Dyrud, L. P.

    2014-12-01

    Software Defined Radio/Radar (SDR) platforms have become increasingly popular as researchers, hobbyists, and military seek more efficient and cost-effective means for radar construction and operation. SDR platforms, by definition, utilize a software-based interface for configuration in contrast to traditional, hard-wired platforms. In an effort to provide new and improved radar sensing capabilities, Penn State has been developing advanced instruments and technologies for future radars, with primary objectives of making such instruments more capable, portable, and more cost effective. This paper will describe the design and implementation of two low-cost radar systems and their deployment in ionospheric research at both low and mid-latitudes. One radar has been installed near Penn State campus, University Park, Pennsylvania (77.97°W, 40.70°N), to make continuous meteor observations and mid-latitude plasma irregularities. The second radar is being installed in Huancayo (12.05°S, -75.33°E), Peru, which is capable of detecting E and F region plasma irregularities as well as meteor reflections. In this paper, we examine and compare the diurnal and seasonal variability of specular, non- specular, and head-echoes collected with these two new radar systems and discuss sampling biases of each meteor observation technique. We report our current efforts to validate and calibrate these radar systems with other VHF radars such as Jicamarca and SOUSY. We also present the general characteristics of continuous measurements of E-region and F-region coherent echoes using these modern radar systems and compare them with coherent radar events observed at other geographic mid-latitude radar stations.

  6. Theoretical and observational determinations of the ionization coefficient of meteors

    NASA Astrophysics Data System (ADS)

    Jones, William

    1997-07-01

    We examine the problem of the determination of the ionization coefficient beta from both the theoretical and observational points of view. In the past, theoretical evaluations of beta in terms of the relevant scattering cross-sections have used the Massey-Sida formula, which we show to give results which are plainly incorrect. We derive an integral equation for beta and compare the results of its application to copper and iron with laboratory simulations. Agreement for the variation of the ionization coefficient with velocity is good. The ionization coefficient has been determined observationally by Verniani & Hawkins from a comparison of radar and visual observations, employing the luminous efficiency tau also obtained observationally by Verniani. However, this determination of tau would appear to be invalidated by fragmentation. There is good evidence that the radiation of cometary meteors is dominated by that of iron in the visual range, and we have accordingly re-analysed the data of Verniani & Hawkins using the luminous efficiency of iron obtained in simulation experiments. However, it is not possible to choose an iron concentration which gives agreement between the determination of the ionization coefficient by this means and its determination from the theoretical equation in terms of either scattering coefficients or simulation methods. The observational ionization coefficients are much lower than predicted by the present theory and we provisionally explain this as a consequence of transfer of charge from the meteoric ion to a molecule of the air. It is now possible for the meteoric atom to be re-ionized, but it is also possible at sufficiently high initial line densities for significant dissociative recombination of the electrons and nitrogen or oxygen to take place. This recombination will not take place in meteor trains simulated in an ionization chamber. We thus conclude that the present theory is limited to faint radio meteors at lower velocities (v<~35

  7. First observational evidence for the connection between the meteoric activity and occurrence of equatorial counter electrojet

    NASA Astrophysics Data System (ADS)

    Vineeth, C.; Mridula, N.; Muralikrishna, P.; Kumar, K. K.; Pant, T. K.

    2016-09-01

    This paper presents the first direct observational evidence for the possible role of meteoric activity in the generation of the equatorial Counter Electrojets (CEJ), an enigmatic daytime electrodynamical process over the geomagnetic equatorial upper atmosphere. The investigation carried out using the data from Proton Precession Magnetometer and Meteor Wind Radar over a geomagnetic dip equatorial station, Trivandrum (8.5°N, 77°E, 0.5°N dip lat.) in India, revealed that the occurrence of the afternoon CEJ events during a month is directly proportional to the average monthly meteor counts over this location. The observation is found to be very consistent during the considered period of study, i.e the years 2006 and 2007. The study vindicates that the meteor showers play a major role in setting up the background condition conducive for the generation of CEJ by reducing the strength of the upward polarization field.

  8. A new meteor echo detection and collection system - Christmas Island mesospheric wind measurements

    NASA Astrophysics Data System (ADS)

    Avery, S. K.; Avery, J. P.; Valentic, T. A.; Palo, S. E.; Leary, M. J.

    1990-08-01

    A second generation meteor echo detection and collection system has been installed on the Christmas Island, Republic of Kiribati, stratosphere-troposphere radar system. Data from the first 6 months of operation have yielded mean wind and tidal climatologies that are compared with theoretical models.

  9. Lunar and Planetary Science XXXV: Asteroids, Meteors, and Comets

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The session "Asteroids, Meteors, and Comets" contained the following reports:Ejecta Generation and Redistribution on 433 Eros: Modeling Ejecta Launch Conditions; Macroscopic Voids in Small Asteroids: Effects of Cohesion; The Seismic Effect of Impacts on Asteroid Surface Morphology: Early Modeling Results; Photometric Studies of Eros from NEAR Data; Quantitative Aspects of Space Weathering: Implications for Regolith Breccia Meteorites and Asteroids; Diversity of Types of Hydrated Minerals on C-Class Asteroids; Mineralogical Variations Among High Albedo E-Type Asteroids: Implications for Asteroid Igneous Processes; Multi-Wavelength Observations of 2100 Ra-Shalom: Radar and Lightcurves; What are the P-type Asteroids Made Of?; Sodium Overabundance in Meteoroids from Meteor Spectroscopy; Migration Processes and Volatiles Inventory to the Inner Planets; Characterization of the Surface Properties of MUSES-C/Hayabusa Spacecraft Target; Asteroid 25143 Itokawa; and Sample Return Science by Hayabusa Near-Earth Asteroid Mission.

  10. Meteor wind results from Atlanta, USA, and Ramey, Puerto Rico

    NASA Technical Reports Server (NTRS)

    Roper, R. G.

    1984-01-01

    Results obtained using the French (CNET) meteor wind radar at Ramey, Puerto Rico, and the Georgia Tech radio meteor wind facility in Atlanta, U.S.A., are presented and compared. Prevailing wind, diurnal, and semidiurnal wind amplitudes are considerably larger over Ramey than over Atlanta, but the mean zonal circulation over Atlanta is more characteristic of the equatorial circulation than winds measured by stations at higher midlatitudes. The value of continuous observations, with a height resolution of + or - 2 km, is emphasized, as is the need for the application of several techniques, groundbased, in situ and satellite, if projects such as the MAP GLOBMET are to succeed in delineating the global meteorology of the mesopause.

  11. Dynamical Model for the Toroidal Sporadic Meteors

    NASA Astrophysics Data System (ADS)

    Pokorný, Petr; Vokrouhlický, David; Nesvorný, David; Campbell-Brown, Margaret; Brown, Peter

    2014-07-01

    More than a decade of radar operations by the Canadian Meteor Orbit Radar have allowed both young and moderately old streams to be distinguished from the dispersed sporadic background component. The latter has been categorized according to broad radiant regions visible to Earth-based observers into three broad classes: the helion and anti-helion source, the north and south apex sources, and the north and south toroidal sources (and a related arc structure). The first two are populated mainly by dust released from Jupiter-family comets and new comets. Proper modeling of the toroidal sources has not to date been accomplished. Here, we develop a steady-state model for the toroidal source of the sporadic meteoroid complex, compare our model with the available radar measurements, and investigate a contribution of dust particles from our model to the whole population of sporadic meteoroids. We find that the long-term stable part of the toroidal particles is mainly fed by dust released by Halley type (long period) comets (HTCs). Our synthetic model reproduces most of the observed features of the toroidal particles, including the most troublesome low-eccentricity component, which is due to a combination of two effects: particles' ability to decouple from Jupiter and circularize by the Poynting-Robertson effect, and large collision probability for orbits similar to that of the Earth. Our calibrated model also allows us to estimate the total mass of the HTC-released dust in space and check the flux necessary to maintain the cloud in a steady state.

  12. Dynamical model for the toroidal sporadic meteors

    SciTech Connect

    Pokorný, Petr; Vokrouhlický, David; Nesvorný, David; Campbell-Brown, Margaret; Brown, Peter E-mail: vokrouhl@cesnet.cz E-mail: margaret.campbell@uwo.ca

    2014-07-01

    More than a decade of radar operations by the Canadian Meteor Orbit Radar have allowed both young and moderately old streams to be distinguished from the dispersed sporadic background component. The latter has been categorized according to broad radiant regions visible to Earth-based observers into three broad classes: the helion and anti-helion source, the north and south apex sources, and the north and south toroidal sources (and a related arc structure). The first two are populated mainly by dust released from Jupiter-family comets and new comets. Proper modeling of the toroidal sources has not to date been accomplished. Here, we develop a steady-state model for the toroidal source of the sporadic meteoroid complex, compare our model with the available radar measurements, and investigate a contribution of dust particles from our model to the whole population of sporadic meteoroids. We find that the long-term stable part of the toroidal particles is mainly fed by dust released by Halley type (long period) comets (HTCs). Our synthetic model reproduces most of the observed features of the toroidal particles, including the most troublesome low-eccentricity component, which is due to a combination of two effects: particles' ability to decouple from Jupiter and circularize by the Poynting-Robertson effect, and large collision probability for orbits similar to that of the Earth. Our calibrated model also allows us to estimate the total mass of the HTC-released dust in space and check the flux necessary to maintain the cloud in a steady state.

  13. Agile Infrastructure Monitoring

    NASA Astrophysics Data System (ADS)

    Andrade, P.; Ascenso, J.; Fedorko, I.; Fiorini, B.; Paladin, M.; Pigueiras, L.; Santos, M.

    2014-06-01

    At the present time, data centres are facing a massive rise in virtualisation and cloud computing. The Agile Infrastructure (AI) project is working to deliver new solutions to ease the management of CERN data centres. Part of the solution consists in a new "shared monitoring architecture" which collects and manages monitoring data from all data centre resources. In this article, we present the building blocks of this new monitoring architecture, the different open source technologies selected for each architecture layer, and how we are building a community around this common effort.

  14. Agile Walking Robot

    NASA Technical Reports Server (NTRS)

    Larimer, Stanley J.; Lisec, Thomas R.; Spiessbach, Andrew J.; Waldron, Kenneth J.

    1990-01-01

    Proposed agile walking robot operates over rocky, sandy, and sloping terrain. Offers stability and climbing ability superior to other conceptual mobile robots. Equipped with six articulated legs like those of insect, continually feels ground under leg before applying weight to it. If leg sensed unexpected object or failed to make contact with ground at expected point, seeks alternative position within radius of 20 cm. Failing that, robot halts, examines area around foot in detail with laser ranging imager, and replans entire cycle of steps for all legs before proceeding.

  15. A fast meteor detection algorithm

    NASA Astrophysics Data System (ADS)

    Gural, P.

    2016-01-01

    A low latency meteor detection algorithm for use with fast steering mirrors had been previously developed to track and telescopically follow meteors in real-time (Gural, 2007). It has been rewritten as a generic clustering and tracking software module for meteor detection that meets both the demanding throughput requirements of a Raspberry Pi while also maintaining a high probability of detection. The software interface is generalized to work with various forms of front-end video pre-processing approaches and provides a rich product set of parameterized line detection metrics. Discussion will include the Maximum Temporal Pixel (MTP) compression technique as a fast thresholding option for feeding the detection module, the detection algorithm trade for maximum processing throughput, details on the clustering and tracking methodology, processing products, performance metrics, and a general interface description.

  16. Leonid meteors, 2001 November 18

    NASA Astrophysics Data System (ADS)

    McGee, H. W.; Mobberley, M. P.

    2002-02-01

    Leonid meteors photographed from Palau, Micronesia, on 2001 November 18. Clockwise from top right: 3 meteors in Corvus, 19.18-19.20 UT; brilliant fireball in Orion, 18.48.30 UT; bright Leonid in Hydra, 19.06 UT. 50mm f/1.8 lens, 1600 ISO Fuji Superia film; M.P. Mobberley. Top left: Composite of three 5-minute exposures between 19.15 and 19.36 UT. 28mm f2.8 lens, 800 ISO Kodak Gold film; H.W. McGee.

  17. Wake in faint television meteors

    NASA Technical Reports Server (NTRS)

    Robertson, M. C.; Hawkes, Robert L.

    1992-01-01

    The two component dustball model was used in numerical lag computation. Detached grain lag is typically less than 2 km, with expected wakes of a few hundred meters. True wake in television meteors is masked by apparent wake due to the combined effects of image persistence and blooming. To partially circumvent this problem, we modified a dual MCP intensified CID video system by addition of a rotating shutter to reduce the effective exposure time to about 2.0 ms. Preliminary observations showed that only 2 of 27 analyzed meteors displayed statistically significant wake.

  18. Momentum loss for antimatter meteors

    NASA Astrophysics Data System (ADS)

    Papaelias, P. M.

    1991-02-01

    The momentum loss for a possible antimatter meteor entrance can be described by the combination of two terms. One which can be characterized by the mechanism of annihilation and a second one, the well known mechanism which is common for all koinomatter (ordinary) meteors. That is, the momentum loss caused by the air molecules swept up by the moving object. This paper discusses the contribution of the rocket effect caused by the action of the secondaries which can be produced by the annihilation interactions of the antiatoms with the air molecules.

  19. The making of meteor astronomy: part V.

    NASA Astrophysics Data System (ADS)

    Beech, M.

    1993-12-01

    The first true comparisons between the observations and the "rising vapors" hypothesis of meteor origins were made in the early eighteenth century. One of the key figures in the new meteoric dialogue was Edmond Halley.

  20. Meteor Shower Identification and Characterization with Python

    NASA Technical Reports Server (NTRS)

    Moorhead, Althea

    2015-01-01

    The short development time associated with Python and the number of astronomical packages available have led to increased usage within NASA. The Meteoroid Environment Office in particular uses the Python language for a number of applications, including daily meteor shower activity reporting, searches for potential parent bodies of meteor showers, and short dynamical simulations. We present our development of a meteor shower identification code that identifies statistically significant groups of meteors on similar orbits. This code overcomes several challenging characteristics of meteor showers such as drastic differences in uncertainties between meteors and between the orbital elements of a single meteor, and the variation of shower characteristics such as duration with age or planetary perturbations. This code has been proven to successfully and quickly identify unusual meteor activity such as the 2014 kappa Cygnid outburst. We present our algorithm along with these successes and discuss our plans for further code development.

  1. ESSAYS ON SCIENCE AND SOCIETY: Of Comets and Meteors.

    PubMed

    Whipple, F L

    2000-08-01

    Fred L. Whipple was born in Iowa in 1906. During his career as an astronomer, he discovered six comets and advanced the study of comets and meteors. He has encouraged amateur astronomers and advised many U.S. governmental and scientific agencies. He deduced that comets consist of ice and dust from observing that their orbits and timing change slightly through the gas vaporization from the ices. In this essay, he recounts highlights of his career, including developing radar-disrupting chaff and the promise of the global positioning system. PMID:17819566

  2. David Levy's Guide to Observing Meteor Showers

    NASA Astrophysics Data System (ADS)

    Levy, David H.

    2007-11-01

    Preface; 1. July 4, 1956; 2. What is a meteor?; 3. Some historical notes; 4. Small rocks and dust in space; 5. Observing meteors; 6. Recording meteors; 7. Quadrantids; 8. Lyrids; 9. The Eta Aquarids; 10. The Omicron Draconids; 11. Delta Aquarids; 12. Perseids; 13. The Gamma Pavonids; 14. Orionids; 15. Taurids; 16. Leonids; 17. Geminids; 18. Ursids; 19. Meteor showers throughout the year; Appendix.

  3. Note on the 1972 Giacobinid meteor shower.

    NASA Technical Reports Server (NTRS)

    Harvey, G. A.

    1973-01-01

    It is shown that the 1972 Giacobinid meteor shower was extremely weak with a peak activity of two to three visual meteors per hour. Only two meteor spectra were obtained from the 17 slitless spectrograph systems operated by the Langley Research Center. The largely unexpected, essentially null results of the 1972 Giacobinid meteor shower observations are indicative of the present limited understanding and predictability of cosmic dust storms.

  4. The new July meteor shower

    NASA Astrophysics Data System (ADS)

    Zoladek, Przemyslaw; Wisniewski, Mariusz

    2012-12-01

    A new meteor stream was found after an activity outburst observed on 2005 July 15. The radiant was located five degrees west of the possible early Perseid radiant, close to the star Zeta Cassiopeiae. Numerous bright meteors and fireballs were observed during this maximum. Analysis of the IMO Video Database and the SonotaCo orbital database revealed an annual stream which is active just before the appearance of the first Perseids, with a clearly visible maximum at solar longitude 113°1. Activity of the stream was estimated as two times higher than activity of the Alpha Capricornids at the same time. The activity period extends from July 12 to 17, during maximum the radiant is visible at coordinates alpha = 5°9, delta = +50°5, and observed meteors are fast, with Vg = 57.4 km/s. The shower was reported to the IAU Meteor Data Center and recognized as a new discovery. According to IAU nomenclature the new stream should be named the Zeta Cassiopeiids (ZCS). %z Arlt R. (1992). WGN, Journal of the IMO, 20:2, 62-69. Drummond J. D. (1981). Icarus, 45, 545-553. Kiraga M. and Olech A. (2001). In Arlt R., Triglav M., and Trayner C., editors, Proceedings of the International Meteor Conference, Pucioasa, Romania, 21-24 September 2000, pages 45-51. IMO. Molau S. (2007). In Bettonvil F. and Kac J., editors, Proceedings of the International Meteor Conference, Roden, The Netherlands, 14-17 September 2006, pages 38-55. IMO. Molau S. and Rendtel J. (2009). WGN, Journal of the IMO, 37:4, 98-121. Olech A., Zoladek P., Wisniewski M., Krasnowski M., Kwinta M., Fajfer T., Fietkiewicz K., Dorosz D., Kowalski L., Olejnik J., Mularczyk K., and Zloczewski K. (2006). In Bastiaens L., Verbert J., Wislez J.-M., and Verbeeck C., editors, Proceedings of the International Meteor Conference, Oostmalle, Belgium, 15-18 September 2005, pages 53-62. IMO. Poleski R. and Szaruga K. (2006). In Bastiaens L., Verbert J., Wislez J.-M., and Verbeeck C., editors, Proceedings of the International Meteor

  5. Croatian Meteor Network: Ongoing work 2015 - 2016

    NASA Astrophysics Data System (ADS)

    Šegon, D.; Vida, D.; Korlević, K.; Andreić, Ž.

    2016-01-01

    Ongoing work of the Croatian Meteor Network (CMN) between the 2015 and 2016 International Meteor Conferences is presented. The current sky coverage is considered, software updates and updates of orbit catalogues are described. Furthermore, the work done on meteor shower searches, international collaborations as well as new fields of research are discussed. Finally, the educational efforts made by the CMN are described.

  6. New trends in meteor radio receivers

    NASA Astrophysics Data System (ADS)

    Rault, Jean-Louis

    2014-01-01

    Recent progresses in low cost—but performing—SDR (software defined radio) technology presents a major breakthrough in the domain of meteor radio observations. Their performances are now good enough for meteor work and should therefore encourage newcomers to join the meteor radio community.

  7. Meteor Crater, AZ

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The Barringer Meteorite Crater (also known as 'Meteor Crater') is a gigantic hole in the middle of the arid sandstone of the Arizona desert. A rim of smashed and jumbled boulders, some of them the size of small houses, rises 50 m above the level of the surrounding plain. The crater itself is nearly a 1500 m wide, and 180 m deep. When Europeans first discovered the crater, the plain around it was covered with chunks of meteoritic iron - over 30 tons of it, scattered over an area 12 to 15 km in diameter. Scientists now believe that the crater was created approximately 50,000 years ago. The meteorite which made it was composed almost entirely of nickel-iron, suggesting that it may have originated in the interior of a small planet. It was 50 m across, weighed roughly 300,000 tons, and was traveling at a speed of 65,000 km per hour. This ASTER 3-D perspective view was created by draping an ASTER bands 3-2-1image over a digital elevation model from the US Geological Survey National Elevation Dataset.

    This image was acquired on May 17, 2001 by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on NASA's Terra satellite. With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER will image Earth for the next 6 years to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18,1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products. Dr. Anne Kahle at NASA's Jet Propulsion Laboratory, Pasadena, California, is the U.S. Science team leader; Bjorn Eng of JPL is the project manager. ASTER is the only high resolution imaging sensor on Terra. The Terra mission is part of NASA's Earth Science Enterprise, along

  8. Advanced SuperDARN meteor wind observations based on raw time series analysis technique

    NASA Astrophysics Data System (ADS)

    Tsutsumi, M.; Yukimatu, A. S.; Holdsworth, D. A.; Lester, M.

    2009-04-01

    The meteor observation technique based on SuperDARN raw time series analysis has been upgraded. This technique extracts meteor information as biproducts and does not degrade the quality of normal SuperDARN operations. In the upgrade the radar operating system (RADOPS) has been modified so that it can oversample every 15 km during the normal operations, which have a range resolution of 45 km. As an alternative method for better range determination a frequency domain interferometry (FDI) capability was also coded in RADOPS, where the operating radio frequency can be changed every pulse sequence. Test observations were conducted using the CUTLASS Iceland East and Finland radars, where oversampling and FDI operation (two frequencies separated by 3 kHz) were simultaneously carried out. Meteor ranges obtained in both ranging techniques agreed very well. The ranges were then combined with the interferometer data to estimate meteor echo reflection heights. Although there were still some ambiguities in the arrival angles of echoes because of the rather long antenna spacing of the interferometers, the heights and arrival angles of most of meteor echoes were more accurately determined than previously. Wind velocities were successfully estimated over the height range of 84 to 110 km. The FDI technique developed here can be further applied to the common SuperDARN operation, and study of fine horizontal structures of F region plasma irregularities is expected in the future.

  9. Agile manufacturing concept

    NASA Astrophysics Data System (ADS)

    Goldman, Steven L.

    1994-03-01

    The initial conceptualization of agile manufacturing was the result of a 1991 study -- chaired by Lehigh Professor Roger N. Nagel and California-based entrepreneur Rick Dove, President of Paradigm Shifts, International -- of what it would take for U.S. industry to regain global manufacturing competitiveness by the early twenty-first century. This industry-led study, reviewed by senior management at over 100 companies before its release, concluded that incremental improvement of the current system of manufacturing would not be enough to be competitive in today's global marketplace. Computer-based information and production technologies that were becoming available to industry opened up the possibility of an altogether new system of manufacturing, one that would be characterized by a distinctive integration of people and technologies; of management and labor; of customers, producers, suppliers, and society.

  10. Aircraft agility maneuvers

    NASA Technical Reports Server (NTRS)

    Cliff, Eugene M.; Thompson, Brian G.

    1992-01-01

    A new dynamic model for aircraft motions is presented. This model can be viewed as intermediate between a point-mass model, in which the body attitude angles are control-like, and a rigid-body model, in which the body-attitude angles evolve according to Newton's Laws. Specifically, consideration is given to the case of symmetric flight, and a model is constructed in which the body roll-rate and the body pitch-rate are the controls. In terms of this body-rate model a minimum-time heading change maneuver is formulated. When the bounds on the body-rates are large the results are similar to the point-mass model in that the model can very quickly change the applied forces and produce an acceleration to turn the vehicle. With finite bounds on these rates, the forces change in a smooth way. This leads to a measurable effect of agility.

  11. DYNAMICAL MODEL FOR THE ZODIACAL CLOUD AND SPORADIC METEORS

    SciTech Connect

    Nesvorny, David; Vokrouhlicky, David; Pokorny, Petr; Bottke, William F.; Janches, Diego

    2011-12-20

    The solar system is dusty, and would become dustier over time as asteroids collide and comets disintegrate, except that small debris particles in interplanetary space do not last long. They can be ejected from the solar system by Jupiter, thermally destroyed near the Sun, or physically disrupted by collisions. Also, some are swept by the Earth (and other planets), producing meteors. Here we develop a dynamical model for the solar system meteoroids and use it to explain meteor radar observations. We find that the Jupiter Family Comets (JFCs) are the main source of the prominent concentrations of meteors arriving at the Earth from the helion and antihelion directions. To match the radiant and orbit distributions, as measured by the Canadian Meteor Orbit Radar (CMOR) and Advanced Meteor Orbit Radar (AMOR), our model implies that comets, and JFCs in particular, must frequently disintegrate when reaching orbits with low perihelion distance. Also, the collisional lifetimes of millimeter particles may be longer ({approx}> 10{sup 5} yr at 1 AU) than postulated in the standard collisional models ({approx}10{sup 4} yr at 1 AU), perhaps because these chondrule-sized meteoroids are stronger than thought before. Using observations of the Infrared Astronomical Satellite to calibrate the model, we find that the total cross section and mass of small meteoroids in the inner solar system are (1.7-3.5) Multiplication-Sign 10{sup 11} km{sup 2} and {approx}4 Multiplication-Sign 10{sup 19} g, respectively, in a good agreement with previous studies. The mass input required to keep the zodiacal cloud in a steady state is estimated to be {approx}10{sup 4}-10{sup 5} kg s{sup -1}. The input is up to {approx}10 times larger than found previously, mainly because particles released closer to the Sun have shorter collisional lifetimes and need to be supplied at a faster rate. The total mass accreted by the Earth in particles between diameters D = 5 {mu}m and 1 cm is found to be {approx}15

  12. Meteor Beliefs Project: Meteors in the Maori astronomical traditions of New Zealand

    NASA Astrophysics Data System (ADS)

    Britton, Tui R.; Hamacher, Duane W.

    2014-02-01

    We review the literature for perceptions of meteors in the Maori culture of Aotearoa or New Zealand. We examine representations of meteors in religion, story, and ceremony. We find that meteors are sometimes personified as gods or children, or are seen as omens of death and destruction. The stories we found highlight the broad perception of meteors found throughout the Maori culture, and note that some early scholars conflated the terms comet and meteor.

  13. Chasing Meteors With a Microscope.

    ERIC Educational Resources Information Center

    Jones, Richard C.

    1993-01-01

    Describes types of meteors and micrometeorites that enter the Earth's atmosphere. Presents an activity where students collect micrometeorites with a strip of tape in an undisturbed outdoor area. After 24 hours, they examine the tape by sandwiching it between 2 glass slides and view through a microscope at 100X. (PR)

  14. Design Architecture and Initial Results from an FPGA Based Digital Receiver for Multistatic Meteor Measurements

    NASA Astrophysics Data System (ADS)

    Palo, Scott; Vaudrin, Cody

    Defined by a minimal RF front-end followed by an analog-to-digital converter (ADC) and con-trolled by a reconfigurable logic device (FPGA), the digital receiver will replace conventional heterodyning analog receivers currently in use by the COBRA meteor radar. A basic hardware overview touches on the major digital receiver components, theory of operation and data han-dling strategies. We address concerns within the community regarding the implementation of digital receivers in small-scale scientific radars, and outline the numerous benefits with a focus on reconfigurability. From a remote sensing viewpoint, having complete visibility into a band of the EM spectrum allows an experiment designer to focus on parameter estimation rather than hardware limitations. Finally, we show some basic multistatic receiver configurations enabled through GPS time synchronization. Currently, the digital receiver is configured to facilitate range and radial velocity determination of meteors in the MLT region for use with the COBRA meteor radar. Initial measurements from data acquired at Platteville, Colorado and Tierra Del Fuego in Argentina will be presented. We show an improvement in detection rates compared to conventional analog systems. Scientific justification for a digital receiver is clearly made by the presentation of RTI plots created using data acquired from the receiver. These plots reveal an interesting phenomenon concerning vacillating power structures in a select number of meteor trails.

  15. Elements of an Art - Agile Coaching

    NASA Astrophysics Data System (ADS)

    Lundh, Erik

    This tutorial gives you a lead on becoming or redefining yourself as an Agile Coach. Introduction to elements and dimensions of state-of-the-art Agile Coaching. How to position the agile coach to be effective in a larger setting. Making the agile transition - from a single team to thousands of people. How to support multiple teams as a coach. How to build a coaches network in your company. Challenges when the agile coach is a consultant and the organization is large.

  16. Video spectra of Leonids and other meteors

    NASA Astrophysics Data System (ADS)

    Borovička, Jiří

    2001-11-01

    Video spectra of 33 meteors of medium brightness (+1 to -1 mag) were compared. The intensity of the main meteoric emissions of Mg, Na, Fe, and atmospheric emissions of N2, O, N were studied. The Na/Mg ratio is different in different meteors, showing variations in Na abundance. Moreover, much earlier ablation of Na during the atmospheric entry than of other elements observed in some Leonids and one Orionid, Quadrantid and Leo Minorid evidences fragile structure of those meteoroids. One sporadic meteor was completely deficient in sodium. The strength of atmospheric emission increases with increasing meteor velocity. Taurids are notable by the near-absence of O and N emissions.

  17. The Telemetry Agile Manufacturing Effort

    SciTech Connect

    Brown, K.D.

    1995-01-01

    The Telemetry Agile Manufacturing Effort (TAME) is an agile enterprising demonstration sponsored by the US Department of Energy (DOE). The project experimented with new approaches to product realization and assessed their impacts on performance, cost, flow time, and agility. The purpose of the project was to design the electrical and mechanical features of an integrated telemetry processor, establish the manufacturing processes, and produce an initial production lot of two to six units. This paper outlines the major methodologies utilized by the TAME, describes the accomplishments that can be attributed to each methodology, and finally, examines the lessons learned and explores the opportunities for improvement associated with the overall effort. The areas for improvement are discussed relative to an ideal vision of the future for agile enterprises. By the end of the experiment, the TAME reduced production flow time by approximately 50% and life cycle cost by more than 30%. Product performance was improved compared with conventional DOE production approaches.

  18. Improving Global Development Using Agile

    NASA Astrophysics Data System (ADS)

    Avritzer, Alberto; Bronsard, Francois; Matos, Gilberto

    Global development promises important productivity and capability advantages over centralized work by optimally allocating tasks according to locality, expertise or cost. All too often, global development also introduces a different set of communication and coordination challenges that can negate all the expected benefits and even cause project failures. Most common problems have to do with building trust or quick feedback loops between distributed teams, or with the integration of globally developed components. Agile processes tend to emphasize the intensity of communication, and would seem to be negatively impacted by team distribution. In our experience, these challenges can be overcome, and agile processes can address some of the pitfalls of global development more effectively than plan-driven development. This chapter discusses how to address the difficulties faced when adapting agile processes to global development and the improvements to global development that adopting agile can produce.

  19. Prediction of meteor shower associated with Comet 122P/de Vico

    NASA Astrophysics Data System (ADS)

    Tomko, Dusan; Neslusan, Lubos

    2013-01-01

    We model, for a far past, a theoretical stream associated with Comet 122P/de Vico and follow its dynamical evolution until present. Selecting the modeled particles approaching the Earth's orbit at the present, we predict the characteristics of a potential meteor shower and try to identify these particles with the meteors in three databases (photo, radar, and video). Our overall prediction is, however, negative because only the particles released from the comet nucleus before approximately 37 000 years ago are found to evolve into a collision course with the Earth and, therefore, form a possible shower. Meteoroids are known to survive a much shorter time in interplanetary space, unfortunately.

  20. On the age and parent body of the daytime Arietids meteor shower

    NASA Astrophysics Data System (ADS)

    Abedin, A.; Wiegert, P.; Pokorny, P.; Brown, P.

    2016-01-01

    The daytime Arietid meteor shower is active from mid-May to late June and is among the strongest of the annual meteor showers, comparable in activity and duration to the Perseids and the Geminids. Due to the daytime nature of the shower, the Arietids have mostly been constrained by radar studies. The Arietids exhibit a long-debated discrepancy in the semi-major axis and the eccentricity of meteoroid orbits as measured by radar and optical surveys. Radar studies yield systematically lower values for the semi-major axis and eccentricity, where the origin of these discrepancies remain unclear. The proposed parent bodies of the stream include comet 96P/Machholz and more recently the Marsden's group of sun-skirting comets. In this work, we present detailed numerical modelling of the daytime Arietid meteoroid stream, with the goal to identifying the parent body and constraining the age of the stream. We use observational data from an extensive survey of the Arietids by the Canadian Meteor Orbit Radar (CMOR), in the period of 2002-2013, and several optical observations by the SonotaCo meteor network and the Cameras for All-sky Meteor Surveillance (CAMS). Our simulations suggest that the age and observed characteristics of the daytime Arietids are consistent with cometary activity from 96P, over the past 12000 years. The sunskirting comets that presumably formed in a major comet breakup between 100 - 950 AD (Chodas and Sekanina, 2005), alone, cannot explain the observed shower characteristics of the Arietids. Thus, the Marsden sunskirters cannot be the dominant parent, though our simulations suggest that they contribute to the core of the stream.

  1. Recent Advances in Video Meteor Photometry

    NASA Technical Reports Server (NTRS)

    Swift, Wesley R.; Suggs, Robert M.; Meachem, Terry; Cooke, William J.

    2003-01-01

    One of the most common (and obvious) problems with video meteor data involves the saturation of the output signal produced by bright meteors, resulting in the elimination of such meteors from photometric determinations. It is important to realize that a "bright" meteor recorded by intensified meteor camera is not what would be considered "bright" by a visual observer - indeed, many Generation II or III camera systems are saturated by meteors with a visual magnitude of 3, barely even noticeable to the untrained eye. As the relatively small fields of view (approx.30 ) of the camera systems captures at best modest numbers of meteors, even during storm peaks, the loss of meteors brighter than +3 renders the determination of shower population indices from video observations even more difficult. Considerable effort has been devoted by the authors to the study of the meteor camera systems employed during the Marshall Space Flight Center s Leonid ground-based campaigns, and a calibration scheme has been devised which can extend the useful dynamic range of such systems by approximately 4 magnitudes. The calibration setup involves only simple equipment, available to amateur and professional, and it is hoped that use of this technique will make for better meteor photometry, and move video meteor analysis beyond the realm of simple counts.

  2. Determination of the Meteor Limiting Magnitude

    NASA Technical Reports Server (NTRS)

    Kingery, A.; Blaauw, R.; Cooke, W. J.

    2016-01-01

    The limiting meteor magnitude of a meteor camera system will depend on the camera hardware and software, sky conditions, and the location of the meteor radiant. Some of these factors are constants for a given meteor camera system, but many change between meteor shower or sporadic source and on both long and short timescales. Since the limiting meteor magnitude ultimately gets used to calculate the limiting meteor mass for a given data set, it is important to have an understanding of these factors and to monitor how they change throughout the night, as a 0.5 magnitude uncertainty in limiting magnitude translates to a uncertainty in limiting mass by a factor of two.

  3. Extraterrestrial meteors: a martian meteor and its parent comet.

    PubMed

    Selsis, Franck; Lemmon, Mark T; Vaubaillon, Jérémie; Bell, James F

    2005-06-01

    Regular meteor showers occur when a planet approaches the orbit of a periodic comet--for example, the Leonid shower is evident around 17 November every year as Earth skims past the dusty trail of comet Tempel-Tuttle. Such showers are expected to occur on Mars as well, and on 7 March last year, the panoramic camera of Spirit, the Mars Exploration Rover, revealed a curious streak across the martian sky. Here we show that the timing and orientation of this streak, and the shape of its light curve, are consistent with the existence of a regular meteor shower associated with the comet Wiseman-Skiff, which could be characterized as martian Cepheids. PMID:15931208

  4. Extraterrestrial meteors: a martian meteor and its parent comet.

    PubMed

    Selsis, Franck; Lemmon, Mark T; Vaubaillon, Jérémie; Bell, James F

    2005-06-01

    Regular meteor showers occur when a planet approaches the orbit of a periodic comet--for example, the Leonid shower is evident around 17 November every year as Earth skims past the dusty trail of comet Tempel-Tuttle. Such showers are expected to occur on Mars as well, and on 7 March last year, the panoramic camera of Spirit, the Mars Exploration Rover, revealed a curious streak across the martian sky. Here we show that the timing and orientation of this streak, and the shape of its light curve, are consistent with the existence of a regular meteor shower associated with the comet Wiseman-Skiff, which could be characterized as martian Cepheids.

  5. Human factors in agile manufacturing

    SciTech Connect

    Forsythe, C.

    1995-03-01

    As industries position themselves for the competitive markets of today, and the increasingly competitive global markets of the 21st century, agility, or the ability to rapidly develop and produce new products, represents a common trend. Agility manifests itself in many different forms, with the agile manufacturing paradigm proposed by the Iacocca Institute offering a generally accepted, long-term vision. In its many forms, common elements of agility or agile manufacturing include: changes in business, engineering and production practices, seamless information flow from design through production, integration of computer and information technologies into all facets of the product development and production process, application of communications technologies to enable collaborative work between geographically dispersed product development team members and introduction of flexible automation of production processes. Industry has rarely experienced as dramatic an infusion of new technologies or as extensive a change in culture and work practices. Human factors will not only play a vital role in accomplishing the technical and social objectives of agile manufacturing. but has an opportunity to participate in shaping the evolution of industry paradigms for the 21st century.

  6. An analytical theory of a scattering of radio-waves on meteoric ionization. II. Solution of the integro-differential equation in case of backscatter

    NASA Astrophysics Data System (ADS)

    Pecina, P.

    2016-08-01

    The integro-differential equation for the polarization vector P inside the meteor trail, representing the analytical solution of the set of Maxwell equations, is solved for the case of backscattering of radio waves on meteoric ionization. The transversal and longitudinal dimensions of a typical meteor trail are small in comparison to the distances to both transmitter and receiver and so the phase factor appearing in the kernel of the integral equation is large and rapidly changing. This allows us to use the method of stationary phase to obtain an approximate solution of the integral equation for the scattered field and for the corresponding generalized radar equation. The final solution is obtained by expanding it into the complete set of Bessel functions, which results in solving a system of linear algebraic equations for the coefficients of the expansion. The time behaviour of the meteor echoes is then obtained using the generalized radar equation. Examples are given for values of the electron density spanning a range from underdense meteor echoes to overdense meteor echoes. We show that the time behaviour of overdense meteor echoes using this method is very different from the one obtained using purely numerical solutions of the Maxwell equations. Our results are in much better agreement with the observations performed e. g. by the Ondřejov radar.

  7. Differential Meteoric Ablation and its affects in the atmosphere (Invited)

    NASA Astrophysics Data System (ADS)

    Plane, J. M.; Broadley, S. L.; Whalley, C. L.; Saunders, R. W.; Gomez Martin, J.; Janches, D.; Dyrud, L.

    2009-12-01

    Differential ablation occurs when the constituents of a molten meteoroid evaporate at different rates during the passage of the meteoroid through the upper atmosphere. This can result in relatively volatile elements (e.g., Na and K) evaporating more than 20 km higher than a refractory element such as Ca. This paper will describe a new chemical ablation model (CABMOD) which predicts the ablation rates of individual elements from a meteoroid under specified entry conditions. The model also treats ionization of the individual elements by hyperthermal collisions with air molecules. This data has been used to compute the fine structure in the altitude profile of the "head echo" which would be observed by a large aperture radar. Good agreement was found with observations from the Arecibo radar in Puerto Rico. CABMOD has also been used to explain the curious results of multiple common-volume lidar observations of meteor trails, and to predict the most likely composition of meteoric smoke particles which result from the recondensation of vaporized meteoroids.

  8. Various meteor scenes III: Recurrent showers and some minor showers

    NASA Astrophysics Data System (ADS)

    Koseki, Masahiro

    2015-02-01

    Meteor activities vary widely from year to year. We study here the June Bootids (JBO), τ-Herculids (TAH), and Andromedids (AND) which are basic examples for the recurrent nature of meteor showers. Half a century has passed since well-known photographic or radar meteor showers were detected. It is necessary to note that some `established' IAU showers are historical ones and we cannot always see them. We find the historical trace of AND by video and four distinct activities in the area of JBC (=JBO+TAH). Meteor showers look different by different observational techniques. Many minor showers in the IAU list have been detected only by observations stored for many days and many years; visual observations in a single night cannot perceive them naturally. We studied the φ-Piscids (PPS), χ-Taurids (CTA), γ-Ursae Minorids (GUM), η-Pegasids (ETP), and α-Sextantids (ASX) as examples and found they have not been recognized by visual observers at all. It is noteworthy that some of them have possible identifications in the IAU list and in preceding observations or reports. The difference in search methods makes the situations much more complicated. The five minor showers we studied here do not have confirmations by all observational techniques. Geobased search (radiant point, time of the observation, and possibly geocentric velocity) may overlook showers which are dispersed in radiant position. A search using the D-criterion is dependent on the presumption of a spherical distribution in the orbital space and may not represent the real distribution, or may overestimate the accuracy of the observations and lead to subdividing the showers into several parts. We must use these search methods properly.

  9. High temperature condensates among meteors

    NASA Technical Reports Server (NTRS)

    Wilkening, L. L.

    1975-01-01

    It is noted that two meteors which exhibited no lines of iron or sodium in their spectra have been tentatively attributed to aubrites in order to explain their lack of iron. It is shown, however, that no meteorites, including aubrites, have simultaneously low abundances of iron and sodium and that possible parent materials other than aubrites must be considered for the observed meteors. Other possible parent materials considered in this letter include melilite and diopside, two minerals containing both Ca and Mg but neither Fe nor Na. It is suggested that meteoroids rich in Ca and Mg but lacking Fe and Na might form a reservoir for the so-called 'lost' elements (Ca, Mg, Al, Ti, the lanthanides, and other refractory elements) which are depleted in ordinary and enstatite chondrites relative to cosmic abundances.

  10. Meteor observations under the INASAN supervision

    NASA Astrophysics Data System (ADS)

    Kartashova, A. P.; Bagrov, A. V.

    2012-09-01

    Meteor observations have the specific property: we do not know in advance neither area on the celestial sphere, not the time when the event occurs. Besides that, a meteor flash in the atmosphere has duration few seconds or less, and it is hard problem to gather enough photons from it to register a faint or fast meteor. There are a number of tasks in meteor astronomy for solution of which not only a simple registration of meteors in the optical range is required, but a high spatial and time resolution as well. Television method is the most acceptable for such a case and is widely used in the practice of meteor observations. Television meteor observations in Russia are carried out under the Institute of Astronomy of the Russian Academy of Sciences (INASAN) supervision in different regions of Russia: Moscow region, Irkutsk, Ryazan and North Caucasus. The TV system PatrolCa designed for observations in the wide field of view (the ordinary for most of meteor cameras), consists of the following components: the high resolution cameras Watec LCL-902HS, the wide-angle photograph objectives Canon 6/0.8 (F=6 mm, the aperture 1:0.8). The cameras have fields of view of 50°x40° and have a limiting magnitude (for meteors) of +4 m ÷ +5 m. The FAVOR (FAst Variability Optical Registrator) camera is used for observations of faint meteors at the North Caucasus [1]. The basic components of this camera are the following: the high-aperture lense objective with the aperture 150 mm and the focal length 180mm (the aperture 1:1.2), the image intensifier, the objective reversal, CCD receiver "Videoscan" VS-СTT285 2001. The CCD "Sony" ICX285 has format 1380 х 1024 pixels. The camera has a field of view of 18 ° х 20°, and has a limiting magnitude of above +10m (for meteors). The two cameras similar to FAVOR (named SMAC) were designed for double-station observations of faint meteors. The results of observations at these cameras are presented. The observations were held by both methods

  11. Collecting Comet Samples by ER-2 Aircraft: Cosmic Dust Collection During the Draconid Meteor Shower in October 2012

    NASA Technical Reports Server (NTRS)

    Bastien, Ron; Burkett, P. J.; Rodriquez, M.; Frank, D.; Gonzalez, C.; Robinson, G.-A.; Zolensky, M.; Brown, P.; Campbell-Brown, M.; Broce, S.; Kapitzke, M.; Moes, T.; Steel, D.; Williams, T.; Gearheart, D.

    2014-01-01

    Many tons of dust grains, including samples of asteroids and comets, fall from space into the Earth's atmosphere each day. NASA periodically collects some of these particles from the Earth's stratosphere using sticky collectors mounted on NASA's high-flying aircraft. Sometimes, especially when the Earth experiences a known meteor shower, a special opportunity is presented to associate cosmic dust particles with a known source. NASA JSC's Cosmic Dust Collection Program has made special attempts to collect dust from particular meteor showers and asteroid families when flights can be planned well in advance. However, it has rarely been possible to make collections on very short notice. In 2012, the Draconid meteor shower presented that opportunity. The Draconid meteor shower, originating from Comet 21P/Giacobini-Zinner, has produced both outbursts and storms several times during the last century, but the 2012 event was not predicted to be much of a show. Because of these predictions, the Cosmic Dust team had not targeted a stratospheric collection effort for the Draconids, despite the fact that they have one of the slowest atmospheric entry velocities (23 km/s) of any comet shower, and thus offer significant possibilities of successful dust capture. However, radar measurements obtained by the Canadian Meteor Orbit Radar during the 2012 Draconids shower indicated a meteor storm did occur October 8 with a peak at 16:38 (+/-5 min) UTC for a total duration of approximately 2 hours.

  12. SPA Meteor Section Results: 2006

    NASA Astrophysics Data System (ADS)

    McBeath, Alastair

    2010-12-01

    A summary of the main analyzed results and other information provided to the SPA Meteor Section from 2006 is presented and discussed. Events covered include: the radio Quadrantid maximum on January 3/4; an impressive fireball seen from parts of England, Belgium and the Netherlands at 22h53m51s UT on July 18, which was imaged from three EFN stations as well; the Southern delta-Aquarid and alpha-Capricornid activity from late July and early August; the radio Perseid maxima on August 12/13; confirmation that the October 5/6 video-meteor outburst was not observed by radio; visual and radio findings from the strong, bright-meteor, Orionid return in October; another impressive UK-observed fireball on November 1/2, with an oil painting of the event as seen from London; the Leonids, which produced a strong visual maximum around 04h-05h UT on November 18/19 that was recorded much less clearly by radio; radio and visual reports from the Geminids, with a note regarding NASA-observed Geminid lunar impact flashes; and the Ursid outburst recorded by various techniques on December 22.

  13. What Does an Agile Coach Do?

    NASA Astrophysics Data System (ADS)

    Davies, Rachel; Pullicino, James

    The surge in Agile adoption has created a demand for project managers rather than direct their teams. A sign of this trend is the ever-increasing number of people getting certified as scrum masters and agile leaders. Training courses that introduce agile practices are easy to find. But making the transition to coach is not as simple as understanding what agile practices are. Your challenge as an Agile Coach is to support your team in learning how to wield their new Agile tools in creating great software.

  14. Big data era in meteor science

    NASA Astrophysics Data System (ADS)

    Vinković, D.; Gritsevich, M.; Srećković, V.; Pečnik, B.; Szabó, G.; Debattista, V.; Škoda, P.; Mahabal, A.; Peltoniemi, J.; Mönkölä, S.; Mickaelian, A.; Turunen, E.; Kákona, J.; Koskinen, J.; Grokhovsky, V.

    2016-01-01

    Over the last couple of decades technological advancements in observational techniques in meteor science have yielded drastic improvements in the quality, quantity and diversity of meteor data, while even more ambitious instruments are about to become operational. This empowers meteor science to boost its experimental and theoretical horizons and seek more advanced science goals. We review some of the developments that push meteor science into the big data era that requires more complex methodological approaches through interdisciplinary collaborations with other branches of physics and computer science. We argue that meteor science should become an integral part of large surveys in astronomy, aeronomy and space physics, and tackle the complexity of micro-physics of meteor plasma and its interaction with the atmosphere.

  15. Meteor Beliefs Project: Meteoric Imagery in SF, Part V: This Island Earth

    NASA Astrophysics Data System (ADS)

    McBeath, Alastair; Gheorghe, Andrei Dorian

    2007-04-01

    The classic 1950s science fiction film This Island Earth is discussed for its meteoric elements, along with a more recent movie which pokes fun at it, by way of celebrating the Meteor Beliefs Project's fourth anniversary.

  16. Piloted simulator assessments of agility

    NASA Technical Reports Server (NTRS)

    Schneider, Edward T.

    1990-01-01

    NASA has utilized piloted simulators for nearly two decades to study high-angle-of-attack flying qualities, agility, and air-to-air combat. These studies have included assessments of an F-16XL aircraft equipped with thrust vectoring, an assessment of the F-18 HARV maneuvering requirements to assist in thrust vectoring control system design, and an agility assessment of the F-18. The F-18 agility assessment was compared with in-flight testing. Open-loop maneuvers such as 180-deg rolls to measure roll rate showed favorable simulator/in-flight comparison. Closed-loop maneuvers such as rolls to 90 deg with precision stops or certain maximum longitudinal pitching maneuvers showed poorer performance due to reduced aggressiveness of pilot inputs in flight to remain within flight envelope limits.

  17. Bi-telescopic, deep, simultaneous meteor observations

    NASA Technical Reports Server (NTRS)

    Taff, L. G.

    1986-01-01

    A statistical summary is presented of 10 hours of observing sporadic meteors and two meteor showers using the Experimental Test System of the Lincoln Laboratory. The observatory is briefly described along with the real-time and post-processing hardware, the analysis, and the data reduction. The principal observational results are given for the sporadic meteor zenithal hourly rates. The unique properties of the observatory include twin telescopes to allow the discrimination of meteors by parallax, deep limiting magnitude, good time resolution, and sophisticated real-time and post-observing video processing.

  18. The 25th International Meteor Conference

    NASA Astrophysics Data System (ADS)

    Roggemans, Paul

    2006-08-01

    Since the founding of the International Meteor Organization, the International Meteor Conferences guaranteed the vital personal contacts between its members. In recent years IMCs were sometimes assumed to have started with IMO. However, the IMCs grew out of a much older initiative, the Meteor Seminars that started in 1979, later also called International Meteor Weekends. These events played a crucial role in the making of the IMO. The 2006 IMC in Roden, the Netherlands later this year is in fact a jubilee edition as it is the 25th edition since the very beginning in 1979!

  19. Generation of a severe convective ionospheric storm under stable Rayleigh-Taylor conditions: triggering by meteors?

    NASA Astrophysics Data System (ADS)

    Kelley, M. C.; Ilma, R. R.

    2016-02-01

    Here we report on four events detected using the Jicamarca Radio Observatory (JRO) over an 18-year period, in which huge convective ionospheric storms (CISs) occur in a stable ionosphere. We argue that these rare events could be initiated by meteor-induced electric fields. The meteor-induced electric fields map to the bottomside of the F region, causing radar echoes and a localized CIS. If and when a localized disturbance reaches 500 km, we argue that it becomes two-dimensionally turbulent and cascades structure to both large and small scales. This leads to long-lasting structure and, almost certainly, to scintillations over a huge range of latitudes some ±15° wide and to 3 m irregularities, which backscatter the VHF radar waves. These structures located at high altitudes are supported by vortices shed by the upwelling bubble in a vortex street.

  20. Software ``Best'' Practices: Agile Deconstructed

    NASA Astrophysics Data System (ADS)

    Fraser, Steven

    This workshop will explore the intersection of agility and software development in a world of legacy code-bases and large teams. Organizations with hundreds of developers and code-bases exceeding a million or tens of millions of lines of code are seeking new ways to expedite development while retaining and attracting staff who desire to apply “agile” methods. This is a situation where specific agile practices may be embraced outside of their usual zone of applicability. Here is where practitioners must understand both what “best practices” already exist in the organization - and how they might be improved or modified by applying “agile” approaches.

  1. Results of observations of the Eta Aquarid and Orionid meteor showers in 1980-1984

    NASA Technical Reports Server (NTRS)

    Hajduk, A.

    1987-01-01

    The main characteristics of meteor showers associated with Comet Halley were derived from the most recent radar observations carried out at the Ondrejov Astronomical Observatory during the periods of May 1 to 10 and October 15 to 30. The activity variations, the positions of activity maxima, the size distribution of particles, the particle flux variation within the stream and other characteristics were determined and compared with other results.

  2. Scattering characteristics of high-resolution meteor head echoes detected at multiple frequencies

    NASA Astrophysics Data System (ADS)

    Close, S.; Oppenheim, M.; Hunt, S.; Dyrud, L.

    2002-10-01

    Meteor data collected at the Kwajalein Missile Range (KMR) during the peak of the 1998 Leonid storm comprise the only simultaneous observations of meteor head echoes and trails using seven frequencies (very high frequency (VHF), ultrahigh frequency (UHF), L-, S-, C-, Ka-, and W-band spanning 160 MHz to 95 GHz). The primary sensor was the ARPA Long-Range Tracking and Instrumentation Radar (ALTAIR) radar operating at 160 MHz with 30 m range resolution and 422 MHz with 7.5 m range resolution, including both interferometric and polarization capabilities. This paper presents an analysis of this high-resolution data set with the following results: First, these observations support the theory that head echo scattering arises from an ionized region with a density sufficiently high that its plasma frequency exceeds the radar frequency (overdense reflection). Second, radar cross section (RCS) decreases rapidly with decreasing wavelength because higher frequencies must penetrate further into the increasing density of the plasma surrounding the meteoroid to reach its reflection point. Third, head echo angle measurements indicate that most of the observed meteors are sporadics not originating from the Leonid radiant. Fourth, polarization ratios showed that head echo reflections result from plasmas with a circular cross section. Fifth, the highest RCS values are detected near 105 km altitude, where the meteoroid gives up the most kinetic energy during its decent. This paper presents the first analyses of a three-frequency head echo as well as the polarization ratios and RCS characteristics from numerous two-frequency head echoes, which will allow us to develop a better understanding of meteor physics.

  3. The Sporadic Meteoroid Environment: Radar and Optical Fluxes

    NASA Astrophysics Data System (ADS)

    Campbell-Brown, M. D.; Braid, D.

    2009-12-01

    Sporadic meteoroids come from comets, asteroids and even outside the solar system, and cannot be directly associated with a parent body. Understanding their origins gives us insight to the distribution, composition and history of their parent bodies. More practically, knowing their spatial density, speed and mass distribution helps to assess the threat to spacecraft in Earth orbit and on interplanetary missions. Recent meteor radar data, obtained with the Canadian Meteor Orbit Radar, has provided the most complete picture of the orbital distribution of meteoroids at the Earth and how that distribution changes with solar longitude. Meteor radars, however, suffer from a significant number of observing biases which are not currently well constrained. Optical systems have many fewer biases, but the collection and analysis of data has been much more labour intensive than in the past. In this work, we present a rigorous method for calculating the collecting area of a two-station video system, and apply the method to calculating the flux of meteoroids from the major sporadic sources. The method is tested on meteor showers, where the activity is better constrained. Fig. 1: Density of radiants of orbits observed with the Canadian Meteor Orbit Radar, 2002 - 2008. Each pixel represents the number of orbits in a 2x2 degree bin, in sun-centered ecliptic coordinates.

  4. Croatian Meteor Network: ongoing work 2014 - 2015

    NASA Astrophysics Data System (ADS)

    Šegon, D.; Andreić, Ž.; Korlević, K.; Vida, D.

    2015-01-01

    Ongoing work mainly between 2014-2015 International Meteor Conferences (IMC) has been presented. Current sky coverage, software updates, orbit catalogues updates, shower search updates, international collaboration as well as new fields of research and educational efforts made by the Croatian Meteor Network are described.

  5. The Makings of Meteor Astronomy: Part XIII

    NASA Astrophysics Data System (ADS)

    Beech, M.

    1996-10-01

    In 1848, Sir John Lubbock advanced the hypothesis that meteors shine by reflected sunlight. He developed a set of equations describing the geometry of meteor encounters, and for a decade or so, his idea was at least marginally supported by other observers.

  6. Models of sporadic meteor body distributions

    NASA Technical Reports Server (NTRS)

    Andreev, V. V.; Belkovich, O. I.

    1987-01-01

    The distribution of orbital elements and flux density over the celestial sphere are the most common forms of representation of the meteor body distribution in the vicinity of the Earth's orbit. The determination of flux density distribution of sporadic meteor bodies was worked out. The method and its results are discussed.

  7. Activity of the Lyrid meteor stream

    NASA Technical Reports Server (NTRS)

    Lindblad, Bertil A.; Porubcan, V.

    1992-01-01

    The activity of the Lyrid meteor stream is in most years fairly low with a visual rate at maximum (21-22 April) of 5-10 meteors per hour. Short bursts of very high Lyrid activity, with visual hourly rates of 100 or more, have sometimes been reported. These observations generally refer to faint visual meteors. The reported bursts of high activity have occurred in a very narrow interval of solar longitudes (deg 31.24 to 31.38 equinox 1950.0), while the recurrent or 'normal' maximum for bright meteors occurs at solar longitude deg 31.6, or slightly later. A mass separation of the meteors in the shower is thus indicated.

  8. Sporadic E-Layers and Meteor Activity

    NASA Astrophysics Data System (ADS)

    Alimov, Obid

    2016-07-01

    In average width it is difficult to explain variety of particularities of the behavior sporadic layer Es ionospheres without attraction long-lived metallic ion of the meteoric origin. Mass spectrometric measurements of ion composition using rockets indicate the presence of metal ions Fe+, Mg+, Si+, Na+, Ca+, K+, Al+ and others in the E-region of the ionosphere. The most common are the ions Fe+, Mg+, Si+, which are primarily concentrated in the narrow sporadic layers of the ionosphere at altitudes of 90-130 km. The entry of meteoric matter into the Earth's atmosphere is a source of meteor atoms (M) and ions (M +) that later, together with wind shear, produce midlatitude sporadic Es layer of the ionosphere. To establish the link between sporadic Es layer and meteoroid streams, we proceeded from the dependence of the ionization coefficient of meteors b on the velocity of meteor particles in different meteoroid streams. We investigated the dependence of the critical frequency f0Es of sporadic E on the particle velocity V of meteor streams and associations. It was established that the average values of f0Es are directly proportional to the velocity V of meteor streams and associations, with the correlation coefficient of 0.53 < R < 0.74. Thus, the critical frequency of the sporadic layer Es increases with the increase of particle velocity V in meteor streams, which indicates the direct influence of meteor particles on ionization of the lower ionosphere and formation of long-lived metal atoms M and ions M+ of meteoric origin.

  9. Auroral effects on meteoric metals in the upper atmosphere

    NASA Astrophysics Data System (ADS)

    Heinselman, Craig James

    1999-12-01

    Meteors deposit many tons of material into Earth's upper atmosphere each day. The physics and chemistry of meteoric metals in the atmosphere have long been active topics of study, but sophisticated models have emerged just recently of the gas-phase chemical reactions that affect the evolution of the state of these metals. At high latitudes, this portion of the upper atmosphere is also shared by the aurora borealis, or northern lights, which dramatically alter the properties of the background plasma. This thesis concerns coupled chemical models and one- dimensional dynamical models that were developed to investigate the effects of auroral ionization on the time evolution of meteoric iron and sodium elements and compounds in the upper atmosphere. These models are used to show that aurorae can result in rapid ionization of recently deposited iron and sodium, with time constants on the order of 15 minutes. The models are also used to investigate the influence of aurorae on the background iron and sodium layers. Because of the nominal altitude of the neutral iron layer, aurorae will not normally have a measurable impact on that constituent. For sodium, on the other hand, the impact is more significant but highly dependent on the chemical makeup of the aurorally produced ions. For either case, sporadic neutral atom layers at auroral altitudes are significantly affected. A case study of radar and lidar measurements from the Sondrestrom Facility in Greenland is used to test the sodium model. Results are presented which are consistent with the model predictions of the effects of the aurorally enhanced ionization. For this specific case, evidence is also presented to support a gas-phase chemical mechanism for the formation of a thin the formation of a thin sporadic sodium layer.

  10. SPA Meteor Section Results: 2007

    NASA Astrophysics Data System (ADS)

    McBeath, Alastair

    2013-08-01

    Information extracted from analyses carried out by the SPA Meteor Section from 2007 is presented and discussed. Events covered include: the radio Quadrantid maximum on January 4; a bright fireball seen from parts of England and imaged from the Netherlands at 19h56m UT on February 6, for which an approximate trajectory was established; radio results from the Lyrids in late April; the Perseid near-peak activity from August and a note on some daylight Perseid observing from Britain using thermal imagers; the radio α-Aurigid maximum on September 1; the Orionid return, which again provided enhanced activity over several consecutive dates in October for visual and radio observers; the radio Leonids, although the probably main peak found visually on November 19 was not recorded thus due to its timing; the typically protracted Geminid maximum period around December 13-15 as observed visually and by radio; and the Ursid outburst, primarily as detected by radio on December 22.

  11. Radar reflectivity

    NASA Astrophysics Data System (ADS)

    1986-07-01

    This TOP describes a method for measuring the radar reflectivity characteristics of aircraft. It uses a rotating platform and various radar systems to obtain calibrated radar Automatic Gain Control values for each degree of aspect angle for the aircraft. The purpose of this test is to provide comparable values of radar reflectivity for Army aircraft at various radar frequencies and parameter for fixed positions and aspect angles on the aircraft. Data collected on each specific aircraft can be used to evaluate radar reflectivity characteristics of aircraft skin material, paint, and structural changes such as flat versus curved surfaces.

  12. Radio Meteors Observations Techniques at RI NAO

    NASA Astrophysics Data System (ADS)

    Vovk, Vasyl; Kaliuzhnyi, Mykola

    2016-07-01

    The Solar system is inhabited with large number of celestial bodies. Some of them are well studied, such as planets and vast majority of big asteroids and comets. There is one group of objects which has received little attention. That is meteoroids with related to them meteors. Nowadays enough low-technology high-efficiency radio-technical solutions are appeared which allow to observe meteors daily. At RI NAO three methodologies for meteor observation are developed: single-station method using FM-receiver, correlation method using FM-receiver and Internet resources, and single-station method using low-cost SDR-receiver.

  13. Diffusion of long-period meteor streams

    NASA Astrophysics Data System (ADS)

    Emel'Ianenko, V. V.

    1992-10-01

    The diffusion of long-period meteor streams is considered on the basis of mappings for the description of planetary perturbations. Formulas for the dispersion of orbital elements under the conditions of limiting stochasticity are obtained. A statistical study of the evolution of meteor streams in the orbits of the Comets Thatcher, P/Swift-Tuttle, P/Halley, and P/Tempel-Tuttle is carried out. It is shown that the dispersion of orbital elements exhibits complex behavior due to the random distribution of meteor particles in the resonant zones.

  14. The 2014 May Camelopardalid Meteor Shower

    NASA Technical Reports Server (NTRS)

    Cooke, Bill; Moser, Danielle

    2014-01-01

    On May 24, 2014 Earth will encounter multiple streams of debris laid down by Comet 209P LINEAR. This will likely produce a new meteor shower, never before seen. Rates predicted to be from 100 to 1000 meteors per hour between 2 and 4 AM EDT, so we are dealing with a meteor outburst, potentially a storm. Peak rate of 200 per hour best current estimate. Difficult to calibrate models due to lack of past observations. Models indicate mm size particles in stream, so potential risk to Earth orbiting spacecraft.

  15. Visual data of minor meteor showers limits of the method

    NASA Technical Reports Server (NTRS)

    Rendtel, Jurgen; Koschack, R.

    1992-01-01

    Visual meteor observations are carried out on a regular basis by many experienced observers worldwide, thus supplying information about activity of meteor showers. The limits of the method are determined by the accuracy of the detection of the meteor trail. This study shows that visual meteor observations provide reliable data for an observable hourly rate of greater than or equal to 3.

  16. The First Confirmed Videorecordings of Lunar Meteor Impacts

    NASA Technical Reports Server (NTRS)

    Dunham, D. W.; Cudnik, B.; Palmer, D. M.; Sada, P. V.; Melosh, J.; Beech, M.; Pellerin, L.; Asher, D.; Frankenberger R.; Venable R.

    2000-01-01

    North American observers recorded at least six meteors striking the Moon's surface during the Leonid meteor shower on 1999 Nov. 18. Each meteor produced a flash that was recorded from at least two separate locations, marking the first confirmed lunar meteor impacts.

  17. An Investigation of Agility Issues in Scrum Teams Using Agility Indicators

    NASA Astrophysics Data System (ADS)

    Pikkarainen, Minna; Wang, Xiaofeng

    Agile software development methods have emerged and become increasingly popular in recent years; yet the issues encountered by software development teams that strive to achieve agility using agile methods are yet to be explored systematically. Built upon a previous study that has established a set of indicators of agility, this study investigates what issues are manifested in software development teams using agile methods. It is focussed on Scrum teams particularly. In other words, the goal of the chapter is to evaluate Scrum teams using agility indicators and therefore to further validate previously presented agility indicators within the additional cases. A multiple case study research method is employed. The findings of the study reveal that the teams using Scrum do not necessarily achieve agility in terms of team autonomy, sharing, stability and embraced uncertainty. The possible reasons include previous organizational plan-driven culture, resistance towards the Scrum roles and changing resources.

  18. A method of long-term radar shower data analysis

    NASA Technical Reports Server (NTRS)

    Simek, M.

    1987-01-01

    Complex photographic and radar meteor observations have been carried out since 1957. Using the available observational data, the density of incident flux of meteoroids was estimated over a wide mass range of 0.001 to 100 g. To avoid the influence of apparatus selectivity a special technique was applied. The application of this technique to the radar shower data analysis is discussed in detail.

  19. Construction of a meteor orbit calculation system for comprehensive meteor observation

    NASA Astrophysics Data System (ADS)

    Mizumoto, S.; Madkour, W.; Yamamoto, M.

    2016-01-01

    At Kochi University of Technology (KUT), the development of an HRO (Ham-band Radio meteor Observation) -Interferometer (IF) was started in 2003, and we realized the meteor orbit calculation system by multiple-site radio observation with GPS time-keeping combining with the 5 channel (5ch) HRO-IF in 2012. Here, we introduce a future plan of comprehensive meteor observation by Radio, Optical and Infrasound observation.

  20. The AGILE gamma-ray astronomy mission

    NASA Astrophysics Data System (ADS)

    Mereghetti, S.; Tavani, M.; Argan, A.; Barbiellini, G.; Caraveo, P.; Chen, A.; Cocco, V.; Costa, E.; Di Cocco, G.; Feroci, M.; Labanti, C.; Lapshov, I.; Lipari, P.; Longo, F.; Morselli, A.; Perotti, F.; Picozza, P.; Pittori, C.; Prest, M.; Rubini, A.; Soffitta, P.; Vallazza, E.; Vercellone, S.; Zanello, D.

    2001-09-01

    We describe the AGILE satellite: a unique tool for high-energy astrophysics in the 30 MeV - 50 GeV range before GLAST. The scientific performances of AGILE are comparable to those of EGRET, despite the much smaller weight and dimensions. The AGILE mission will be optimized for the imaging capabilities above 30 MeV and for the study of transient phenomena, complemented by simultaneous monitoring in the hard X-ray band (10 - 40 keV).

  1. Comet C/1917 F1 (Mellish) meteor shower complex

    NASA Astrophysics Data System (ADS)

    Hajdukova, M.; Neslusan, L.

    2014-07-01

    In this study, we mapped the whole meteor complex of the long-period comet C/1917 F1 (Mellish), using a procedure of proven reliability when investigating the 96P/Machholz and 2003 EH1 streams (Neslusan et al., 2013a; 2013b). For five perihelion passages of the comet C/1917 F1 in the past, we modeled associated theoretical streams, each consisting of 10000 test particles, and followed their dynamical evolution until the present. Subsequently, we analyzed the orbital characteristics of the parts of a stream that approach the Earth's orbit. These particles were used to predict the corresponding meteor showers. The predicted showers were searched for in the databases of actually observed meteors. According to our modeling, the meteoroid stream of the comet Mellish can be split into 4 filaments (F1 to F4), with 4 distinct radiant areas. The most numerous shower that originates in the comet nucleus of C/1917 F1 corresponds to theoretical filament F3. The meteoroids of this filament approach to the Earth's orbit relatively soon after their ejection from the nucleus. We identified this filament as the December Monocerotids (No. 19 in the IAU MDC list of the established showers). In the phase space of orbital elements, the shower occurs in the vicinity of another established shower, 250 November Orionids. However, shower No. 250 is obviously not related to C/1917 F1 since no single theoretical particle, in all five models, is in an orbit similar to the mean orbit of this shower. Filament F1 might be identified to 348 April rho-Cygnids, the meteoroid stream that was recently discovered by the Canadian Meteor Orbit Radar (Brown et al., 2010). In our models, this filament is numerous and, hence, the shower is well predicted. The particles of filament F1 and, therefore, the real April rho-Cygnids originating in C/1917 F1 can approach the Earth's orbit and collide with our planet not earlier than about 20 millennia after their release from the parent-comet nucleus. Despite this

  2. Systematic forward scatter radar observations of radio waves from meteoroid streams

    NASA Astrophysics Data System (ADS)

    Cevolani, G.; Bortolotti, G.; Foschini, L.; Franceschi, C.; Gabucci, M. F.; Trivellone, G.

    1996-07-01

    Forward scatter (FS) continuous wave (CW) meteor radar observations carried out during 1992-95 over the long baseline Bologna-Lecce in Italy, enabled us to determine the mass distribution versus duration of particles in main meteoroid streams (Lyrids, eta Aquarids, delta Aquarids, Perseids, Orionids, Leonids, Geminids) and the sporadic background. The unexpected high proportion of short-lived echoes with duration T < 0.2s suggests that the missing mass of meteor particles observed so far by backscatter radars in the 1E-6 - 1E-4 g mass range, is present in the form of faint high-velocity meteors, which ablate above the echo ceiling of conventional radars. The trends of the mass distribution of particles for the quoted meteor complexes are discussed in terms of variation of the mass index s and of steady-state conditions for each meteor population. The combined cumulative distributions of meteor trails vs peak signal amplitudes and vs durations represent a more reliable indicator of the meteoroid stream activity and, consequently, of the mass index variation. The mass index values of the sporadic background are generally higher than for meteor showers in the duration range of 0.1

  3. The determination of parameters of the upper atmosphere by the radio-meteor measurements

    NASA Astrophysics Data System (ADS)

    Shamukov, Damir; Fahrutdinova, Antonina; Nugmanov, Ildus

    Study of the parameters of the upper atmosphere on the basis of amplitude-time characteristics of meteor ionization. Together with various methods meteor observations (optical, photographic, visual, spectral, television), the most effective modern method of studying meteors means is radar. The development of modern radar technology allows us to apply this tool to monitor meteors. This method allows to determine the parameters of temperature and atmospheric pressure. Actual issue is the development of methods of determining the coefficient of ambipolar diffusion, pressure, density and temperature of the atmosphere in the meteor zone. Graph of amplitude-time characteristic has the exponential form. This fact allows to determine the coefficient of ambipolar diffusion. New algorithm for estimation of the ambipolar diffusion coefficient based on a set of statistical methods and techniques of digital signal processing. There are decomposition of data on singular values and Prony's method. This method of modeling the sample data as a linear combination of exponential. Prony’s method approximates the amplitude-time characteristics of using a deterministic exponential model. Input data is amplitude-time characteristics of the meteor trail x[1]…x[N]. The method allows to estimate x[n] p-membered exponential model: begin{center} x[n]=Sigma2A_{k}exp[a _{k}(n-1)]Cos[2Pif_{k}(n-1)T+Fi_{k}] (1) end{center} 1<=n<=N, T - time range in seconds, A_{k} and a_{k} - amplitude and damping coefficient, f_{k} and Fi_{k} - frequency and initial phase. The equation describing the decay of radio signal: begin{center} A=A_{0}exp(-16Pi^{2}$D_{a}t/λ (2) ). (2) lambdaλ - radar wavelength. The output of the algorithm - the ambipolar diffusion coefficient values D_{a}. begin{center} T=0.5lnD-T_{0}+mg/2kT_{0} (3) Last equation allows to obtain temperature values ​​using the coefficient of ambipolar diffusion depends on the height.

  4. SAGE III/Meteor - 3M

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Full view of the SAGE III Bench Checkout Unit, Collimated Source Bench (CSB), Portable Image Generator (PIG) on tripod, and Stratospheric Aerosol Gastropheric Experiment (SAGE)/Meteor - 3M flight instrument. Photographed in building 1250, 40 foot clean room.

  5. SAGE III/Meteor - 3M

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Back view of the SAGE III Bench Checkout Unit, Portable Image Generator (PIG) on tripod, and the Stratospheric Aerosol Gastropheric Experiment (SAGE)/Meteor - 3M flight instrument. Photographed in building 1250, 40 foot clean room.

  6. SAGE III/Meteor - 3M

    NASA Technical Reports Server (NTRS)

    1999-01-01

    From left to right: Richard Rawls, Chip Holloway, and Art Hayhurst standing next to the Stratospheric Aerosol Gastropheric Experiment (SAGE)/Meteor - 3M flight instrument. Photographed in building 1250, 40 foot clean room.

  7. Meteor showers associated with 2003EH1

    NASA Astrophysics Data System (ADS)

    Babadzhanov, P. B.; Williams, I. P.; Kokhirova, G. I.

    2008-06-01

    Using the Everhart RADAU19 numerical integration method, the orbital evolution of the near-Earth asteroid 2003EH1 is investigated. This asteroid belongs to the Amor group and is moving on a comet-like orbit. The integrations are performed over one cycle of variation of the perihelion argument ω. Over such a cycle, the orbit intersect that of the Earth at eight different values of ω. The orbital parameters are different at each of these intersections and so a meteoroid stream surrounding such an orbit can produce eight different meteor showers, one at each crossing. The geocentric radiants and velocities of the eight theoretical meteor showers associated with these crossing points are determined. Using published data, observed meteor showers are identified with each of the theoretically predicted showers. The character of the orbit and the existence of observed meteor showers associated with 2003EH1 confirm the supposition that this object is an extinct comet.

  8. Monte Carlo modeling and meteor showers

    NASA Technical Reports Server (NTRS)

    Kulikova, N. V.

    1987-01-01

    Prediction of short lived increases in the cosmic dust influx, the concentration in lower thermosphere of atoms and ions of meteor origin and the determination of the frequency of micrometeor impacts on spacecraft are all of scientific and practical interest and all require adequate models of meteor showers at an early stage of their existence. A Monte Carlo model of meteor matter ejection from a parent body at any point of space was worked out by other researchers. This scheme is described. According to the scheme, the formation of ten well known meteor streams was simulated and the possibility of genetic affinity of each of them with the most probable parent comet was analyzed. Some of the results are presented.

  9. Man-Sized Meteor Over Macon

    NASA Video Gallery

    Astronomers at NASA's Marshall Space Flight Center have recorded the brightest meteor ever seen by their network. On May 20, 2011, six-foot diameter fragment of an unknown comet entered the atmosph...

  10. Large Meteor Tracked over Northeast Alabama

    NASA Video Gallery

    On the evening of May 18, NASA all-sky meteor cameras located at NASA’s Marshall Space Flight Center and at the Walker County Science Center near Chickamauga, Ga. tracked the entry of a large meteo...

  11. Comparison with Russian analyses of meteor impact

    SciTech Connect

    Canavan, G.H.

    1997-06-01

    The inversion model for meteor impacts is used to discuss Russian analyses and compare principal results. For common input parameters, the models produce consistent estimates of impactor parameters. Directions for future research are discussed and prioritized.

  12. Radar principles

    NASA Technical Reports Server (NTRS)

    Sato, Toru

    1989-01-01

    Discussed here is a kind of radar called atmospheric radar, which has as its target clear air echoes from the earth's atmosphere produced by fluctuations of the atmospheric index of refraction. Topics reviewed include the vertical structure of the atmosphere, the radio refractive index and its fluctuations, the radar equation (a relation between transmitted and received power), radar equations for distributed targets and spectral echoes, near field correction, pulsed waveforms, the Doppler principle, and velocity field measurements.

  13. Diurnal tidal wind estimates using TIDI and ground-based radars

    NASA Astrophysics Data System (ADS)

    Riggin, D.; Lieberman, R.; Wu, Q.; Franke, S.

    In this presentation we compare characteristics of the diurnal tide as viewed by the TIDI instrument and ground-based radars at tropical latitudes. The TIDI winds have been retrieved using a new broad-band filter that greatly enhances the signal-to-noise ratio. We investigate the use of global 12-hour differences to obtain tidal amplitudes on a time-scale of 10 days or shorter. The tidal winds are viewed from the ground using radars in the Hawaian Islands and on the Island of Rarotonga in the Cook Islands. The two Hawaian radars involved in the study are a medium frequency (MF) partial reflection radar on Kauai, and meteor scatter radar on Kauai. The Rarotonga site similarly has both an MF and meteor scatter radar. The Hawaii and Rarotonga locations are almost exactly conjugate (22 deg N and 22 deg S, respectively), and thus are well situated for making tidal comparisons.

  14. SEC Vidicon spectra of Geminid meteors, 1972

    NASA Technical Reports Server (NTRS)

    Millman, P. M.; Clifton, K. S.

    1975-01-01

    The SEC Vidicon, a low light level closed circuit television system, was used to obtain 137 spectrographic records of meteors at Mt. Hopkins, Arizona, during the Geminid meteor shower in December 1972. Seven of the best Geminid meteor spectra are studied here in detail. The near infrared, out to wavelengths near 9000 A, is recorded for the first time for Geminids. The spectra, in general, exhibit the elements previously found in photographic records of this shower but show a surprising frequency of occurrence of the forbidden green line of O I at 5577 A. This line is normally absent from meteors moving as slowly as the Geminids (36 km/sec) and its presence in these records may be due to the added sensitivity available with the SEC Vidicon. The average green line duration in Geminid meteors with a luminosity near zero absolute visual magnitude is 0.73 sec at a mean height of 95 km, 11 km lower than the green line peak in Perseid meteors of the same luminosity.

  15. Small-scale structures in common-volume meteor wind measurements

    NASA Astrophysics Data System (ADS)

    Fraser, G. J.; Marsh, S. H.; Baggaley, W. J.; Bennett, R. G. T.; Lawrence, B. N.; McDonald, A. J.; Plank, G. E.

    2006-02-01

    Observational differences occur when different techniques are used for measuring mesospheric winds because the different instruments observe different physical quantities to infer the wind velocity, and have differing time and space resolution. The AMOR meteor wind radar near Christchurch, New Zealand [Marsh et al., 2000. Journal of Atmospheric and Solar-Terrestrial Physics 62,1129 1133.] has good resolution in time (˜0.1 s) and height (˜1 km) and a narrow beam centred in the geographic N S meridian. The meteor echoes randomly sample the atmosphere in a region extending over several hundred kilometres to the South of the radar. The volume of data obtained from the one instrument has made it possible to use correlations between measurements made from individual meteor trails to identify the contribution of atmospheric variability to the observational differences. Measurements of the meridional wind component made from May July 1997 inclusive show that a large part (20 30 m/s r.m.s.) of the atmospheric variation is due to inhomogeneities with small scales, of the order of 10 km and 1 h. There is also a component which has a random time phase over the observation interval but a spatial scale which is coherent over several hundred kilometres, consistent with the behaviour of gravity waves.

  16. Meteoric Ions in Planetary Ionospheres

    NASA Technical Reports Server (NTRS)

    Pesnell, W. D.; Grebowsky, Joseph M.; Vondrak, Richard R. (Technical Monitor)

    2001-01-01

    Solar system debris, in the form of meteoroids, impacts every planet. The flux, relative composition and speed of the debris at each planet depends on the planet's size and location in the solar system. Ablation in the atmosphere evaporates the meteoric material and leaves behind metal atoms. During the ablation process metallic ions are formed by impact ionization. For small inner solar system planets, including Earth, this source of ionization is typically small compared to either photoionization or charge exchange with ambient molecular ions. For Earth, the atmosphere above the main deposition region absorbs the spectral lines capable of ionizing the major metallic atoms (Fe and Mg) so that charge exchange with ambient ions is the dominant source. Within the carbon dioxide atmosphere of Mars (and possibly Venus), photoionization is important in determining the ion density. For a heavy planet like Jupiter, far from the sun, impact ionization of ablated neutral atoms by impacts with molecules becomes a prominent source of ionization due to the gravitational acceleration to high incident speeds. We will describe the processes and location and extent of metal ion layers for Mars, Earth and Jupiter, concentrating on flagging the uncertainties in the models at the present time. This is an important problem, because low altitude ionosphere layers for the planets, particularly at night, probably consist predominantly of metallic ions. Comparisons with Earth will be used to illustrate the differing processes in the three planetary atmospheres.

  17. January and February Meteor Showers Detected by CAMS: the Cameras for Allsky Meteor Surveillance

    NASA Astrophysics Data System (ADS)

    Johnson, Beth; Jenniskens, P. M.

    2014-01-01

    Many meteor showers are in need of validation. Of 493 meteor showers listed in the IAU Working List of Mete-or Showers, only 95 are established. Of the rest, it is uncertain whether they exist or not. The goal of the Cameras for Allsky Meteor Surveillance (CAMS) project in California is to validate or remove the remaining 325 showers. CAMS scales up the use of low-light-level video for meteor triangulation, by deploying 60 video cameras spread over three sites. Once the video data has been analyzed, showers can be confirmed by comparing arrival time, direc-tion of the radiant, and speed of the individual meteors. Once established, showers can be linked to their parent bod-ies and meteoroid streams. The CAMS stations are located in Sunnyvale, at Fremont Peak Observatory, and at Lick Observatory, to the south and east of Sunnyvale, respectively. Each station contains 20 low-light-level security cameras arrayed to view the entire sky above 30°. During the night, the video data from the cameras is written to disk and analysed in day-time with the MeteorScan software package to find moving objects. Eight-second video sequences are saved for all detections. The video sequences are combined at the SETI Institute, where astrometric calibration files are generated and meteors detected from at least two stations simultaneously are found interactively using the Coincidence program. Coincidence also calculates the radiant and velocity of each meteor. Here, we discuss results obtained in January and February 2013. Over 7,500 meteor orbits were cataloged in this period. This outcome doubled the detection rate from the previous two years of CAMS data.We will present graphs of the detected meteor showers and discuss their parent body sources.

  18. The Leonids: The Lion King of Meteor Showers

    NASA Astrophysics Data System (ADS)

    Rao, J.

    1995-08-01

    -lived display in 1966 that possibly rivaled even the 1833 display. Radar observations of this 1966 display showed the densest part of the Leonid stream to be just 35000 km wide; the Earth swept through this filament of debris in just one hour. With the impending return of P/Tempel-Tuttle due in February 1998, prospect for another Leonid storm have begun to increase again. D.K. Yeomans' definitive study (1981) concerning the orbit of P/Tempel-Tuttle and its implications on future Leonid activity is examined. Yeomans takes into account the distribution of dust surrounding P/Tempel-Tuttle, determining that the majority of dust ejected from the comet evolves to a position lagging behind the comet and outside of its orbit. This is likely an artifact of solar radiation pressure and planetary perturbations on the Leonid particles. In 1994, Yeomans re-calculated the orbit of P/Tempel-Tuttle and re-computed future Leonid shower maxima. Yeomans notes that the conditions in 1998-1999 are optimum for a significant Leonid shower, but cautions that such an event is not certain because the dust particle distribution near the comet is far from uniform. The author concurs with Yeomans on this final point and concludes, based on the previous six Leonid epochs, that there is a possibility of a storm in any year from 1997 through 2000. He also believes that no reliable prediction as to the time of Leonid maximum for any given year can be made because we would be trying to anticipate interception not just a single stream along the orbit of P/Tempel-Tuttle, but possibly one of several: each stream having evolved from the solid debris spewed by the comet at previous perihelion passages. To get a storm, Earth must somehow interact with another dense, yet narrow filament of meteoric material which, unfortunately, cannot be anticipated or seen until it impacts with Earth's atmosphere. Still, the upcoming years hold the potential of some truly exciting observing with the prospects of much-better than

  19. Multiply-agile encryption in high speed communication networks

    SciTech Connect

    Pierson, L.G.; Witzke, E.L.

    1997-05-01

    Different applications have different security requirements for data privacy, data integrity, and authentication. Encryption is one technique that addresses these requirements. Encryption hardware, designed for use in high-speed communications networks, can satisfy a wide variety of security requirements if that hardware is key-agile, robustness-agile and algorithm-agile. Hence, multiply-agile encryption provides enhanced solutions to the secrecy, interoperability and quality of service issues in high-speed networks. This paper defines these three types of agile encryption. Next, implementation issues are discussed. While single-algorithm, key-agile encryptors exist, robustness-agile and algorithm-agile encryptors are still research topics.

  20. The GLAST-AGILE Support Program (GASP)

    NASA Astrophysics Data System (ADS)

    Villata, M.; Raiteri, C. M.; Webt Collaboration

    2008-10-01

    The GLAST-AGILE Support Program (GASP) was organized within the Whole Earth Blazar Telescope to provide optical-to-radio long-term continuous monitoring of a list of selected gamma-ray-loud blazars during the operation of the AGILE and GLAST satellites. We present some results obtained since its birth, in September 2007.

  1. Teaching Agile Software Development: A Case Study

    ERIC Educational Resources Information Center

    Devedzic, V.; Milenkovic, S. R.

    2011-01-01

    This paper describes the authors' experience of teaching agile software development to students of computer science, software engineering, and other related disciplines, and comments on the implications of this and the lessons learned. It is based on the authors' eight years of experience in teaching agile software methodologies to various groups…

  2. An Agile Course-Delivery Approach

    ERIC Educational Resources Information Center

    Capellan, Mirkeya

    2009-01-01

    In the world of software development, agile methodologies have gained popularity thanks to their lightweight methodologies and flexible approach. Many advocates believe that agile methodologies can provide significant benefits if applied in the educational environment as a teaching method. The need for an approach that engages and motivates…

  3. The Introduction of Agility into Albania.

    ERIC Educational Resources Information Center

    Smith-Stevens, Eileen J.; Shkurti, Drita

    1998-01-01

    Describes a plan to introduce and achieve a national awareness of agility (and easy entry into the world market) for Albania through the relatively stable higher-education order. Agility's four strategic principles are enriching the customer, cooperating to enhance competitiveness, organizing to master change and uncertainty, and leveraging the…

  4. Prediction of evolution of meteor shower associated with comet 122P/de Vico

    NASA Astrophysics Data System (ADS)

    Tomko, D.

    2014-04-01

    We deal with a theoretical meteoroid stream of the comet 122P/de Vico. For five perihelion passages in the distant past, we model a theoretical stream and follow its dynamical evolution until the present. We predict the characteristics of potential a meteor shower approaching the Earth's orbit and we make also the identification of the particles of the predicted shower with the real meteors in three databases (photo, radar, and video). Our overall prediction is, however, negative because only the particles released from the comet nucleus before approximately 37 000 years are found to evolve into a collision course with the Earth and, therefore, form a possible shower. Many meteoroids do not survive such a long time in interplanetary space.

  5. Some Findings Concerning Requirements in Agile Methodologies

    NASA Astrophysics Data System (ADS)

    Rodríguez, Pilar; Yagüe, Agustín; Alarcón, Pedro P.; Garbajosa, Juan

    Agile methods have appeared as an attractive alternative to conventional methodologies. These methods try to reduce the time to market and, indirectly, the cost of the product through flexible development and deep customer involvement. The processes related to requirements have been extensively studied in literature, in most cases in the frame of conventional methods. However, conclusions of conventional methodologies could not be necessarily valid for Agile; in some issues, conventional and Agile processes are radically different. As recent surveys report, inadequate project requirements is one of the most conflictive issues in agile approaches and better understanding about this is needed. This paper describes some findings concerning requirements activities in a project developed under an agile methodology. The project intended to evolve an existing product and, therefore, some background information was available. The major difficulties encountered were related to non-functional needs and management of requirements dependencies.

  6. Agile manufacturing from a statistical perspective

    SciTech Connect

    Easterling, R.G.

    1995-10-01

    The objective of agile manufacturing is to provide the ability to quickly realize high-quality, highly-customized, in-demand products at a cost commensurate with mass production. More broadly, agility in manufacturing, or any other endeavor, is defined as change-proficiency; the ability to thrive in an environment of unpredictable change. This report discusses the general direction of the agile manufacturing initiative, including research programs at the National Institute of Standards and Technology (NIST), the Department of Energy, and other government agencies, but focuses on agile manufacturing from a statistical perspective. The role of statistics can be important because agile manufacturing requires the collection and communication of process characterization and capability information, much of which will be data-based. The statistical community should initiate collaborative work in this important area.

  7. Agile manufacturing prototyping system (AMPS)

    SciTech Connect

    Garcia, P.

    1998-05-09

    The Agile Manufacturing Prototyping System (AMPS) is being integrated at Sandia National Laboratories. AMPS consists of state of the industry flexible manufacturing hardware and software enhanced with Sandia advancements in sensor and model based control; automated programming, assembly and task planning; flexible fixturing; and automated reconfiguration technology. AMPS is focused on the agile production of complex electromechanical parts. It currently includes 7 robots (4 Adept One, 2 Adept 505, 1 Staubli RX90), conveyance equipment, and a collection of process equipment to form a flexible production line capable of assembling a wide range of electromechanical products. This system became operational in September 1995. Additional smart manufacturing processes will be integrated in the future. An automated spray cleaning workcell capable of handling alcohol and similar solvents was added in 1996 as well as parts cleaning and encapsulation equipment, automated deburring, and automated vision inspection stations. Plans for 1997 and out years include adding manufacturing processes for the rapid prototyping of electronic components such as soldering, paste dispensing and pick-and-place hardware.

  8. CT-assisted agile manufacturing

    NASA Astrophysics Data System (ADS)

    Stanley, James H.; Yancey, Robert N.

    1996-11-01

    The next century will witness at least two great revolutions in the way goods are produced. First, workers will use the medium of virtual reality in all aspects of marketing, research, development, prototyping, manufacturing, sales and service. Second, market forces will drive manufacturing towards small-lot production and just-in-time delivery. Already, we can discern the merging of these megatrends into what some are calling agile manufacturing. Under this new paradigm, parts and processes will be designed and engineered within the mind of a computer, tooled and manufactured by the offspring of today's rapid prototyping equipment, and evaluated for performance and reliability by advanced nondestructive evaluation (NDE) techniques and sophisticated computational models. Computed tomography (CT) is the premier example of an NDE method suitable for future agile manufacturing activities. It is the only modality that provides convenient access to the full suite of engineering data that users will need to avail themselves of computer- aided design, computer-aided manufacturing, and computer- aided engineering capabilities, as well as newly emerging reverse engineering, rapid prototyping and solid freeform fabrication technologies. As such, CT is assured a central, utilitarian role in future industrial operations. An overview of this exciting future for industrial CT is presented.

  9. Asteroid 1620 Geographos: II. Associated Meteor Streams

    NASA Astrophysics Data System (ADS)

    Ryabova, G. O.

    2002-05-01

    This study attempts to answer the following questions. Are there meteor streams genetically related to asteroid 1620 Geographos? When and how were they generated? Can we find any of them in the catalogs of orbits of meteors that have been observed? Numerous model streams, varying in particle-ejection scheme and in the moment of generation, have been considered. It has been found that the meteor streams observed from the Earth were most likely produced as a result of a collision with a small body. However, the generation of the meteor stream under the combined effect of rotation and tidal forces during the asteroid's close approach to the Earth cannot also be ruled out. Meteoroid streams formed at high ejection velocities (up to 1 km/s) can approach the Earth's orbit twice per orbital period: once before perihelion (in February-March) and once after perihelion (in August). The 44 orbits close to the model ones were found in the catalogs of meteoroid orbits. A taxonomic structure has been built for them. The distribution of ejection velocities for the models of Earth-approaching meteoroids points to the impact of an overtaking body, but the moment of collision remains unknown. Thus, it is quite possible that asteroid Geographos is the parent body for twin meteor showers observed at the Earth: Spring and Autumn Geographids.

  10. CAMS confirmation of previously reported meteor showers

    NASA Astrophysics Data System (ADS)

    Jenniskens, P.; Nénon, Q.; Gural, P. S.; Albers, J.; Haberman, B.; Johnson, B.; Holman, D.; Morales, R.; Grigsby, B. J.; Samuels, D.; Johannink, C.

    2016-03-01

    Leading up to the 2015 IAU General Assembly, the International Astronomical Union's Working List of Meteor Showers included 486 unconfirmed showers, showers that are not certain to exist. If confirmed, each shower would provide a record of past comet or asteroid activity. Now, we report that 41 of these are detected in the Cameras for Allsky Meteor Surveillance (CAMS) video-based meteor shower survey. They manifest as meteoroids arriving at Earth from a similar direction and orbit, after removing the daily radiant drift due to Earth's motion around the Sun. These showers do exist and, therefore, can be moved to the IAU List of Established Meteor Showers. This adds to 31 previously confirmed showers from CAMS data. For each shower, finding charts are presented based on 230,000 meteors observed up to March of 2015, calculated by re-projecting the drift-corrected Sun-centered ecliptic coordinates into more familiar equatorial coordinates. Showers that are not detected, but should have, and duplicate showers that project to the same Sun-centered ecliptic coordinates, are recommended for removal from the Working List.

  11. BRAMS: The Belgian RAdio Meteor Stations

    NASA Technical Reports Server (NTRS)

    Lamy, H.; Ranvier, S.; De Keyser, J.; Calders, S.; Gamby, E.; Verbeeck, C.

    2011-01-01

    In the last months, the Belgian Institute for Space Aeronomy has been developing a Belgian network for observing radio meteors using forward scattering technique. This network is called BRAMS for Belgian RAdio Meteor Stations. Two beacons emitting a circularly polarized pure sine wave toward the zenith act as the transmitters at frequencies of 49.97 and 49.99 MHz. The first one located in Dourbes (Southern Belgium) emits a constant power of 150 Watts while the one located in Ieper (Western Belgium) emits a constant power of 50 Watts. The receiving network consists of about 20 stations hosted mainly by radio amateurs. Two stations have crossed-Yagi antennas measuring horizontal and vertical polarizations of the waves reflected off meteor trails. This will enable a detailed analysis of the meteor power profiles from which physical parameters of the meteoroids can be obtained. An interferometer consisting of 5 Yagi-antennas will be installed at the site of Humain in order to determine the angular detection of one reflection point, allowing us to determine meteoroid trajectories. We describe this new meteor observing facility and present the goals we expect to achieve with the network.

  12. Weather Radar

    NASA Astrophysics Data System (ADS)

    Vivekanandan, Jothiram

    2004-10-01

    Weather radar is an indispensable component for remote sensing of the atmosphere, and the data and products derived from weather radar are routinely used in climate and weather-related studies to examine trends, structure, and evolution. The need for weather remote sensing is driven by the necessity to understand and explain a specific atmospheric science phenomenon. The importance of remote sensing is especially evident in high-profile observational programs, such as the WSR-88D (Weather Surveillance Radar) network, TRMM (Tropical Rainfall Measuring Mission), and ARM (Atmospheric Radiation Measurement). A suite of ground-based and airborne radar instruments is maintained and deployed for observing wind, clouds, and precipitation. Weather radar observation has become an integral component of weather forecasting and hydrology and climate studies. The inclusion of weather radar observations in numerical weather modeling has enhanced severe storm forecasting, aviation weather, hurricane intensity and movement, and the global water cycle.

  13. The Urbana coherent-scatter radar: Synthesis and first results

    NASA Technical Reports Server (NTRS)

    Gibbs, K. P.; Bowhill, S. A.

    1979-01-01

    A coherent scatter radar system was synthesized and several hundred hours of echo power and line of sight velocity data obtained. The coherent scatter radar utilizes a diode array and components from meteor radar. The receiving system permits a time resolution of one minute in the data. Echo power from the D region shows a high degree of variability from day to day. Examples of changes in power level at shorter time scales are observed. Velocity data show the existence of gravity waves and occasionally exhibit vertical standing wave characteristics.

  14. Optical Meteor Systems Used by the NASA Meteoroid Environment Office

    NASA Technical Reports Server (NTRS)

    Kingery, A. M.; Blaauw, R. C.; Cooke, W. J.; Moser, D. E.

    2015-01-01

    The NASA Meteoroid Environment Office (MEO) uses two main meteor camera networks to characterize the meteoroid environment: an all sky system and a wide field system to study cm and mm size meteors respectively. The NASA All Sky Fireball Network consists of fifteen meteor video cameras in the United States, with plans to expand to eighteen cameras by the end of 2015. The camera design and All-Sky Guided and Real-time Detection (ASGARD) meteor detection software [1, 2] were adopted from the University of Western Ontario's Southern Ontario Meteor Network (SOMN). After seven years of operation, the network has detected over 12,000 multi-station meteors, including meteors from at least 53 different meteor showers. The network is used for speed distribution determination, characterization of meteor showers and sporadic sources, and for informing the public on bright meteor events. The NASA Wide Field Meteor Network was established in December of 2012 with two cameras and expanded to eight cameras in December of 2014. The two camera configuration saw 5470 meteors over two years of operation with two cameras, and has detected 3423 meteors in the first five months of operation (Dec 12, 2014 - May 12, 2015) with eight cameras. We expect to see over 10,000 meteors per year with the expanded system. The cameras have a 20 degree field of view and an approximate limiting meteor magnitude of +5. The network's primary goal is determining the nightly shower and sporadic meteor fluxes. Both camera networks function almost fully autonomously with little human interaction required for upkeep and analysis. The cameras send their data to a central server for storage and automatic analysis. Every morning the servers automatically generates an e-mail and web page containing an analysis of the previous night's events. The current status of the networks will be described, alongside with preliminary results. In addition, future projects, CCD photometry and broadband meteor color camera

  15. Atmospheric trajectories and light curves of shower meteors

    NASA Astrophysics Data System (ADS)

    Koten, P.; Borovička, J.; Spurný, P.; Betlem, H.; Evans, S.

    2004-12-01

    Double station data on 496 meteors belonging to several meteor showers were obtained within the program of the video meteor observations during years 1998-2001. Analyzed meteors cover a range of photometric masses from 10-7 to 10-4 kg with a corresponding range of maximum brightness from +4.7 to -2.1 absolute magnitude. Atmospheric trajectories of Perseid, Orionid and Leonid meteors are analysed. These typical cometary high velocity meteors are compared to Geminid meteors with probable asteroidal origin and Taurid meteors - another cometary shower with significantly lower entry velocity. The light curves of the studied meteors vary widely, but generally are nearly symmetrical with the point of maximum brightness located close the to middle of the luminous trajectory. Small differences between showers are reported. We found that the height data are in good agreement with the dust-ball model predictions. The only difference is the beginning height behaviour. The beginning heights of cometary meteors increase with increasing photometric mass. These meteoroids probably contain a volatile part which starts to ablate before we are able to detect the meteors. The Geminid meteors are a different case. They start to ablate suddenly and their beginning height is almost constant in the whole range of studied meteoroid masses. In this case we observe real beginnings of meteor ablation.

  16. Planetary Radar

    NASA Technical Reports Server (NTRS)

    Neish, Catherine D.; Carter, Lynn M.

    2015-01-01

    This chapter describes the principles of planetary radar, and the primary scientific discoveries that have been made using this technique. The chapter starts by describing the different types of radar systems and how they are used to acquire images and accurate topography of planetary surfaces and probe their subsurface structure. It then explains how these products can be used to understand the properties of the target being investigated. Several examples of discoveries made with planetary radar are then summarized, covering solar system objects from Mercury to Saturn. Finally, opportunities for future discoveries in planetary radar are outlined and discussed.

  17. ROAN Remote radio meteor detection sensor

    NASA Astrophysics Data System (ADS)

    Lesanu, C. E.

    2016-01-01

    Only few meteor enthusiasts across the world today, approaches systematically the radio meteor detection technique, one of the reasons being the difficulty to build and install proper permanent antennas, especially when low-VHF frequency opportunity transmitters are used as illuminators. Other reasons were in the past the relatively high cost of the entire system, receivers and computers, and not ultimately the high power consumption of the system in a 24/7 operation, when using regular personal computers. The situation changed in the recent years with the advent of the low cost software defined radio SDR receivers and low consumption/cost single board computers SBC. A commercial off-the-shelf hardware based remote radio meteor detection sensor is presented.

  18. All-sky Meteor Orbit System AMOS and preliminary analysis of three unusual meteor showers

    NASA Astrophysics Data System (ADS)

    Tóth, Juraj; Kornoš, Leonard; Zigo, Pavol; Gajdoš, Štefan; Kalmančok, Dušan; Világi, Jozef; Šimon, Jaroslav; Vereš, Peter; Šilha, Jiří; Buček, Marek; Galád, Adrián; Rusňák, Patrik; Hrábek, Peter; Ďuriš, František; Rudawska, Regina

    2015-12-01

    All-sky Meteor Orbit System (AMOS) is a semi-autonomous video observatory for detection of transient events on the sky, mostly the meteors. Its hardware and software development and permanent placement on several locations in Slovakia allowed the establishment of Slovak Video Meteor Network (SVMN) monitoring meteor activity above the Central Europe. The data reduction, orbital determination and additional results from AMOS cameras - the SVMN database - as well as from observational expeditions on Canary Islands and in Canada provided dynamical and physical data for better understanding of mutual connections between parent bodies of asteroids and comets and their meteoroid streams. We present preliminary results on exceptional and rare meteor streams such as September ɛ Perseids (SPE) originated from unknown long periodic comet on a retrograde orbit, suspected asteroidal meteor stream of April α Comae Berenicids (ACO) in the orbit of meteorites Příbram and Neuschwanstein and newly observed meteor stream Camelopardalids (CAM) originated from Jupiter family comet 209P/Linear.

  19. Analysis of historical meteor and meteor shower records: Korea, China, and Japan

    NASA Astrophysics Data System (ADS)

    Yang, Hong-Jin; Park, Changbom; Park, Myeong-Gu

    2005-05-01

    We have compiled and analyzed historical Korean meteor and meteor shower records in three Korean official history books, Samguksagi which covers the three Kingdoms period (57 B.C.-A.D. 935), Goryeosa of Goryeo dynasty (A.D. 918-1392), and Joseonwangjosillok of Joseon dynasty (A.D. 1392-1910). We have found 3861 meteor and 31 meteor shower records. We have confirmed the peaks of Perseids and an excess due to the mixture of Orionids, north-Taurids, or Leonids through the Monte Carlo test. The peaks persist from the period of Goryeo dynasty to that of Joseon dynasty, for almost one thousand years. Korean records show a decrease of Perseids activity and an increase of Orionids/north-Taurids/Leonids activity. We have also analyzed seasonal variation of sporadic meteors from Korean records. We confirm the seasonal variation of sporadic meteors from the records of Joseon dynasty with the maximum number of events being roughly 1.7 times the minimum. The Korean records are compared with Chinese and Japanese records for the same periods. Major features in Chinese meteor shower records are quite consistent with those of Korean records, particularly for the last millennium. Japanese records also show Perseids feature and Orionids/north-Taurids/Leonids feature, although they are less prominent compared to those of Korean or Chinese records.

  20. Opening up the Agile Innovation Process

    NASA Astrophysics Data System (ADS)

    Conboy, Kieran; Donnellan, Brian; Morgan, Lorraine; Wang, Xiaofeng

    The objective of this panel is to discuss how firms can operate both an open and agile innovation process. In an era of unprecedented changes, companies need to be open and agile in order to adapt rapidly and maximize their innovation processes. Proponents of agile methods claim that one of the main distinctions between agile methods and their traditional bureaucratic counterparts is their drive toward creativity and innovation. However, agile methods are rarely adopted in their textbook, "vanilla" format, and are usually adopted in part or are tailored or modified to suit the organization. While we are aware that this happens, there is still limited understanding of what is actually happening in practice. Using innovation adoption theory, this panel will discuss the issues and challenges surrounding the successful adoption of agile practices. In addition, this panel will report on the obstacles and benefits reported by over 20 industrial partners engaged in a pan-European research project into agile practices between 2006 and 2009.

  1. The First Year of Croatian Meteor Network

    NASA Astrophysics Data System (ADS)

    Andreic, Zeljko; Segon, Damir

    2010-08-01

    The idea and a short history of Croatian Meteor Network (CMN) is described. Based on use of cheap surveillance cameras, standard PC-TV cards and old PCs, the Network allows schools, amateur societies and individuals to participate in photographic meteor patrol program. The network has a strong educational component and many cameras are located at or around teaching facilities. Data obtained by these cameras are collected and processed by the scientific team of the network. Currently 14 cameras are operable, covering a large part of the croatian sky, data gathering is fully functional, and data reduction software is in testing phase.

  2. Electrophonic sounds from large meteor fireballs

    NASA Astrophysics Data System (ADS)

    Keay, Colin S. L.

    1992-06-01

    Anomalous sounds from large meteor fireballs, anomalous because they are audible simultaneously with the sighting, have been a matter for debate for over two centuries. Only a minority of observers perceive them. Ten years ago a viable physical explanation was developed (Keay, 1980) which accounts for the phenomenon in terms of ELF/VLF radiation from the fireball plasma being transduced into acoustic waves whenever appropriate objects happen to be in the vicinity of an observer. This explanation has now been verified observationally and supported by other evidence including the study of meteor fireball light curves reported here.

  3. An Investigation of Meteors in Early April

    NASA Astrophysics Data System (ADS)

    Arter, Terrance R.; Williams, Iwan P.

    1995-01-01

    In conducting a search through the IAU Meteor Catalogue at Lund, a peak in activity on April 8th, not corresponding to any known shower was discovered. Analysis of the orbit shows that a subset of those meteors originated on very coherent orbits. It is suggested that there could either represent a hither to unidentified stream or that they are meteoroids which, like the April Lyrids, were ejected from Comet Thatcher but have arrived onto their current orbits as a consequence primarily of Poynting - Robertson drag.

  4. Antarctic ozone - Meteoric control of HNO3

    NASA Astrophysics Data System (ADS)

    Prather, Michael J.; Rodriguez, Jose M.

    1988-01-01

    Atmospheric circulation leads to an accumulation of debris from meteors in the Antarctic stratosphere at the beginning of austral spring. The major component of meteoric material is alkaline, comprised predominantly of the oxides of magnesium and iron. These metals may neutralize the natural acidity of stratospheric aerosols, remove nitric acid from the gas phase, and bond it as metal nitrates in the aerosol phase. Removal of nitric acid vapor has been previously shown to be a critical link in the photochemical depletion of ozone in the Antarctic spring, by allowing for increased catalytic loss from chlorine and bromine.

  5. Meteor spectra from AMOS video system

    NASA Astrophysics Data System (ADS)

    Gajdoš, Š.; Tóth, J.; Kornoš, L.

    2015-01-01

    We present a report on the observation of enhanced activity from the Ursids meteor shower using the all-sky camera, at the AGO Modra, on Dec. 22-23, 2014. The time of maximum is in good accordance with the predictions of some authors. We derived a single-station meteor radiant, RA = 217.9° ± 0.1°, DEC = +76.4° ± 0.1° at solar longitude S.L. = 270.9°, along with the activity profile of the Ursid outburst with the maximum occurring at Dec. 23th, 00h40m UT ± 30 min.

  6. Meteor spectra from AMOS video system

    NASA Astrophysics Data System (ADS)

    Rudawska, Regina; Tóth, Juraj; Kalmančok, Dušan; Zigo, Pavol; Matlovič, Pavol

    2016-04-01

    Here we demonstrate the capability of the updated All-Sky Meteor Orbit System (AMOS) (called AMOS-Spec) to measure the main element abundances of meteors. The AMOS-Spec program has been created with the intention of carrying out regular systematic spectroscopic observations. At the same time, the meteoroid trajectory and pre-atmospheric orbit are independently measured from data collected by the AMOS camera network. This, together with spectral information, allows us to find the link between the meteoroid and its parent body, from both dynamical and physical consideration. Here we report results for 35 selected cases.

  7. In Situ Measurements of Meteoric Ions

    NASA Technical Reports Server (NTRS)

    Grebowsky, Joseph M.; Aiken, Arthur C.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    Extraterrestrial material is the source of metal ions in the Earth's atmosphere, Each year approx. 10(exp 8) kg of material is intercepted by the Earth. The origin of this material is predominantly solar orbiting interplanetary debris from comets or asteroids that crosses the Earth's orbit. It contains a very small amount of interstellar material. On occasion the Earth passes through enhanced amounts of debris associated with the orbit of a decaying comet. This leads to enhanced meteor shower displays for up to several days. The number flux of shower material is typically several times the average sporadic background influx of material. Meteoric material is some of the earliest material formed in the solar system. By studying the relative elemental abundances of atmospheric metal ions, information can be gained on the chemical composition of cometary debris and the chemical makeup of the early solar system. Using in situ sampling with rocket-borne ion mass spectrometers; there have been approximately 50 flights that made measurements of the metal ion abundances at attitudes between 80 and 130 km. It is this altitude range where incoming meteoric particles am ablated, the larger ones giving rise to visible meteor. displays. In several rocket measurements isotopic ratios of different atomic ion mass components and metal molecular ion concentrations have been determined and used to identify unambiguously the measured species and to investigate the processes controlling the metal ion distributions The composition of the Earth's ionosphere was first sampled by an ion mass spectrometer flown an a rocket in 1956. In 1958 a rocket-borne ion spectrometer identified, fbr the first time, a layer of metal ions near 95 km. These data were interpreted as evidence of an extraterrestrial rather than a terrestrial source. Istomin predicted: "It seems probable that with some improvement in the method that analysis of the ion composition in the E-region may be used for determining

  8. The Radio Meteor Zoo: a citizen science project

    NASA Astrophysics Data System (ADS)

    Calders, S.; Verbeeck, C.; Lamy, H.; Martínez Picar, A.

    2016-01-01

    Scientists from the BRAMS radio meteor network have started a citizen science project called Radio Meteor Zoo in collaboration with Zooniverse in order to identify meteor reflections in BRAMS spectrograms. First, a small-scale version of the Radio Meteor Zoo was carried out with a sample of meteor identifications in 12 spectrograms by 35 volunteers. Results are presented here and allowed us to define a method that reliably detects meteor reflections based on the identifications by the volunteers. It turns out that, if each spectrogram is inspected by 10 volunteers, hit and false detection percentages of 95% respectively 6% are expected. The Radio Meteor Zoo is online at https://www.zooniverse.org/projects/zooniverse/radio-meteor-zoo. Citizen scientists are kindly invited to inspect spectrograms.

  9. Exploring the relationship between meteor parameters based on photographic data

    NASA Astrophysics Data System (ADS)

    Yancheva, Y.; Hristova, S.; Bojurova, E.

    2016-01-01

    The paper presents an attempt to investigate the relationship between the luminosity and the linear length of the meteors, based on photographic observations of the Geminid meteor shower during the night of maximum in December 2015.

  10. Independent identification of meteor showers in EDMOND database

    NASA Astrophysics Data System (ADS)

    Rudawska, R.; Matlovič, P.; Tóth, J.; Kornoš, L.

    2015-12-01

    Cooperation and data sharing among national networks and International Meteor Organization Video Meteor Database (IMO VMDB) resulted in European viDeo MeteOr Network Database (EDMOND). The current version of the database (EDMOND 5.0) contains 144 749 orbits collected from 2001 to 2014. This paper presents the results obtained by a proposed new independent method of meteor showers identification, which is applied to the current version of the database (EDMOND 5.0). In the first step of the survey we used the DSH criterion to find groups around each meteor within the similarity threshold. Mean parameters of the groups were calculated and compared using a new function DX based on geocentric parameters (λ⊙, α, δ, and Vg). Similar groups were merged into final clusters (representing meteor showers), and compared with the IAU Meteor Data Center list of meteor showers.

  11. Social Protocols for Agile Virtual Teams

    NASA Astrophysics Data System (ADS)

    Picard, Willy

    Despite many works on collaborative networked organizations (CNOs), CSCW, groupware, workflow systems and social networks, computer support for virtual teams is still insufficient, especially support for agility, i.e. the capability of virtual team members to rapidly and cost efficiently adapt the way they interact to changes. In this paper, requirements for computer support for agile virtual teams are presented. Next, an extension of the concept of social protocol is proposed as a novel model supporting agile interactions within virtual teams. The extended concept of social protocol consists of an extended social network and a workflow model.

  12. Seasonal and diurnal variability of the meteor flux at high latitudes observed using PFISR

    NASA Astrophysics Data System (ADS)

    Sparks, J. J.; Janches, D.; Nicolls, M. J.; Heinselman, C. J.

    2009-05-01

    We report in this and a companion paper [Fentzke, J.T., Janches, D., Sparks, J.J., 2008. Latitudinal and seasonal variability of the micrometeor input function: A study using model predictions and observations from Arecibo and PFISR. Journal of Atmospheric and Solar-Terrestrial Physics, this issue, doi:10.1016/j.jastp.2008.07.015] a complete seasonal study of the micrometeor input function (MIF) at high latitudes using meteor head-echo radar observations performed with the Poker Flat Incoherent Scatter Radar (PFISR). This flux is responsible for a number of atmospheric phenomena; for example, it could be the source of meteoric smoke that is thought to act as condensation nuclei in the formation of ice particles in the polar mesosphere. The observations presented here were performed for full 24-h periods near the summer and winter solstices and spring and autumn equinoxes, times at which the seasonal variability of the MIF is predicted to be large at high latitudes [Janches, D., Heinselman, C.J., Chau, J.L., Chandran, A., Woodman, R., 2006. Modeling of the micrometeor input function in the upper atmosphere observed by High Power and Large Aperture Radars, JGR, 11, A07317, doi:10.1029/2006JA011628]. Precise altitude and radar instantaneous line-of-sight (radial) Doppler velocity information are obtained for each of the hundreds of events detected every day. We show that meteor rates, altitude, and radial velocity distributions have a large seasonal dependence. This seasonal variability can be explained by a change in the relative location of the meteoroid sources with respect to the observer. Our results show that the meteor flux into the upper atmosphere is strongly anisotropic and its characteristics must be accounted for when including this flux into models attempting to explain related aeronomical phenomena. In addition, the measured acceleration and received signal strength distribution do not seem to depend on season; which may suggest that these observed

  13. Optical studies of meteors at Mount Hopkins Observatory

    NASA Technical Reports Server (NTRS)

    Weekes, T. C.; Williams, J. T.

    1974-01-01

    The 10-m optical reflector and an array of phototubes are used to extend the optical measurements beyond the present limit achieved by the Vidicon system. The first detection of optical meteors with M sub v = + 12 is reported. It is hoped that this system can be used to determine intermediate points in the meteor frequency mass curve for sporadic meteors and to study in detail the faint components of meteor showers. Preliminary observations made on three nights in September 1974 are presented.

  14. On associations of Apollo asteroids with meteor streams

    NASA Technical Reports Server (NTRS)

    Porubcan, V.; Stohl, Jan; Vana, R.

    1992-01-01

    Potential associations of Apollo asteroids with meteor streams are searched on the basis of the orbital parameters comparison. From all Apollo asteroids discovered through 1991 June those are only selected for further analysis whose orbits approach to less than 0.1 AU to the Earth's orbit. Their orbits are compared with precise photographic orbits of individual meteors from the Meteor Data Center in Lund. Results on the associations of asteroids with meteor streams are presented and discussed.

  15. Meteor Search by Spirit, Sol 668

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Annotated Meteor Search by Spirit, Sol 668

    The panoramic cameras on NASA's Mars Exploration Rovers are about as sensitive as the human eye at night. The cameras can see the same bright stars that we can see from Earth, and the same patterns of constellations dot the night sky. Scientists on the rover team have been taking images of some of these bright stars as part of several different projects. One project is designed to try to capture 'shooting stars,' or meteors, in the martian night sky. 'Meteoroids' are small pieces of comets and asteroids that travel through space and eventually run into a planet. On Earth, we can sometimes see meteoroids become brilliant, long 'meteors' streaking across the night sky as they burn up from the friction in our atmosphere. Some of these meteors survive their fiery flight and land on the surface (or in the ocean) where, if found, they are called 'meteorites.' The same thing happens in the martian atmosphere, and Spirit even accidentally discovered a meteor while attempting to obtain images of Earth in the pre-dawn sky back in March, 2004 (see http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20040311a.html, and Selsis et al. (2005) Nature, vol 435, p. 581). On Earth, some meteors come in 'storms' or 'showers' at predictable times of the year, like the famous Perseid meteor shower in August or the Leonid meteor shower in November. These 'storms' happen when Earth passes through the same parts of space where comets sometimes pass. The meteors we see at these times are from leftover debris that was shed off of these comets.

    The same kind of thing is predicted for Mars, as well. Inspired by calculations about Martian meteor storms by meteor scientists from the University of Western Ontario in Canada and the Centre de Recherche en Astrophysique de Lyon in France, and also aided by other meteor research colleagues from NASA's Marshall Space Flight Center, scientists on

  16. Spaceborne radar

    NASA Technical Reports Server (NTRS)

    Moore, R. K.; Eckerman, J.; Meneghini, R.; Atlas, D.; Boerner, W. M.; Cherry, S.; Clark, J. F.; Doviak, R. J.; Goldhirsh, J.; Lhermitte, R. M.

    1981-01-01

    The spaceborne radar panel considered how radar could be used to measure precipitation from satellites. The emphasis was on how radar could be used with radiometry (at microwave, visible (VIS), and infrared (IR) wavelengths) to reduce the uncertainties of measuring precipitation with radiometry alone. In addition, the fundamental electromagnetic interactions involved in the measurements were discussed to determine the key work areas for research and development to produce effective instruments. Various approaches to implementing radar systems on satellites were considered for both shared and dedicated instruments. Finally, a research and development strategy was proposed for establishing the parametric relations and retrieval algorithms required for extracting precipitation information from the radar and associated radiometric data.

  17. Results of the IMO Video Meteor Network - June 2015

    NASA Astrophysics Data System (ADS)

    Molau, Sirko; Kac, Javor; Crivello, Stefano; Stomeo, Enrico; Barentsen, Geert; Goncalves, Rui; Saraiva, Carlos; Maciejewski, Maciej; Maslov, Mikhail

    2015-10-01

    Observations of the IMO Video Meteor Network are presented for 2015 June. Activity profile is presented for the Daytime Arietids, based on 28 shower meteors. The meteor rate of the Daytime Arietids between June 5 and 11, normalized for the limiting magnitude and angular velocity, is found to be about one quarter of that of the eta-Aquariids during their maximum.

  18. Results of the IMO Video Meteor Network - October 2014

    NASA Astrophysics Data System (ADS)

    Molau, Sirko; Kac, Javor; Crivello, Stefano; Stomeo, Enrico; Barentsen, Geert; Goncalves, Rui; Saraiva, Carlos; Maciewski, Maciej; Maslov, Mikhail

    2015-02-01

    A record number of 86 cameras of the IMO Video Meteor Network collected over 11 000 hours worth of data in 2014 October, recording almost 52 000 meteors. Yearly flux density profiles are presented for the Orionids, Leonis Minorids, October Camelopardalids, and October Ursae Majorids, covering the period from 2011 to 2014. Population indexes are calculated for all four meteor showers.

  19. Easy way to estimate meteor brightness on TV frames

    NASA Astrophysics Data System (ADS)

    Leonov, V. A.; Bagrov, A. V.

    2016-01-01

    The traditional method of the meteor brightness measurements claims that the meteor brightness is equal to the stellar magnitude of a star that looks like a meteor in the brightest point of its track. This rule was convenient for the comparison of meteor observations by different observers and for the analysis of the brightness distributions of meteors from observed showers. This traditional method suffers from systematic errors, particularly those that arise from using stellar brightness measured in specific spectral wave bands different from the observer's ones, but mainly due to neglecting the influence of the meteor angular velocity on the real meteor brightness. To get a proper estimate of the meteor brightness that is a measure of the ground meteor illumination in the non-systematic units, an observer must take into account that the effective exposition of a meteor image in any resolution element of its track is a few times shorter than the corresponding exposition of a star image in the same frame. We propose a very simple method for improved estimations of meteor brightness by applying a correction to the meteor stellar magnitude obtained within the traditional framework.

  20. The activity of autumn meteor showers in 2006-2008

    NASA Astrophysics Data System (ADS)

    Kartashova, Anna

    2015-03-01

    The purpose of meteor observations in INASAN is the study of meteor showers, as the elements of the migrant substance of the Solar System, and estimation of risk of hazardous collisions of spacecrafts with the particles of streams. Therefore we need to analyze the meteor events with brightness of up to 8 m, which stay in meteoroid streams for a long time and can be a hazardous for the spacecraft. The results of our single station TV observations of autumn meteor showers for the period from 2006 to 2008 are presented. The high-sensitive hybrid camera (the system with coupled of the Image Intensifier) FAVOR with limiting magnitude for meteors about 9m. . .10m in the field of view 20 × 18 was used for observations. In 2006-2008 from October to November more than 3 thousand of meteors were detected, 65% from them have the brightness from 6m to 9m. The identification with autumn meteor showers (Orionids, Taurids, Draconids, Leonids) was carried out. In order to estimate the density of the influx of meteor matter to the Earth for these meteor showers the Index of meteor activity (IMA) was calculated. The IMA distribution for the period 2006 - 2008 is given. The distributions of autumn meteor showers (the meteors with brightness of up to 8 m) by stellar magnitude from 2006 to 2008 are also presented.

  1. 47 CFR 90.250 - Meteor burst communications.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Meteor burst communications. 90.250 Section 90... PRIVATE LAND MOBILE RADIO SERVICES Non-Voice and Other Specialized Operations § 90.250 Meteor burst communications. Meteor burst communications may be authorized for the use of private radio stations subject...

  2. 47 CFR 90.250 - Meteor burst communications.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Meteor burst communications. 90.250 Section 90... PRIVATE LAND MOBILE RADIO SERVICES Non-Voice and Other Specialized Operations § 90.250 Meteor burst communications. Meteor burst communications may be authorized for the use of private radio stations subject...

  3. 47 CFR 90.250 - Meteor burst communications.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Meteor burst communications. 90.250 Section 90... PRIVATE LAND MOBILE RADIO SERVICES Non-Voice and Other Specialized Operations § 90.250 Meteor burst communications. Meteor burst communications may be authorized for the use of private radio stations subject...

  4. 47 CFR 90.250 - Meteor burst communications.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Meteor burst communications. 90.250 Section 90... PRIVATE LAND MOBILE RADIO SERVICES Non-Voice and Other Specialized Operations § 90.250 Meteor burst communications. Meteor burst communications may be authorized for the use of private radio stations subject...

  5. 47 CFR 90.250 - Meteor burst communications.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Meteor burst communications. 90.250 Section 90... PRIVATE LAND MOBILE RADIO SERVICES Non-Voice and Other Specialized Operations § 90.250 Meteor burst communications. Meteor burst communications may be authorized for the use of private radio stations subject...

  6. Meteor Shower Activity Derived from "Meteor Watching Public-Campaign" in Japan

    NASA Technical Reports Server (NTRS)

    Sato, M.; Watanabe, J.

    2011-01-01

    We tried to analyze activities of meteor showers from accumulated data collected by public campaigns for meteor showers which were performed as outreach programs. The analyzed campaigns are Geminids (in 2007 and 2009), Perseids (in 2008 and 2009), Quadrantids (in 2009) and Orionids (in 2009). Thanks to the huge number of reports, the derived time variations of the activities of meteor showers is very similar to those obtained by skilled visual observers. The values of hourly rates are about one-fifth (Geminids 2007) or about one-fourth (Perseids 2008) compared with the data of skilled observers, mainly due to poor observational sites such as large cities and urban areas, together with the immature skill of participants in the campaign. It was shown to be highly possible to estimate time variation in the meteor shower activity from our campaign.

  7. Automated Meteor Fluxes with a Wide-Field Meteor Camera Network

    NASA Technical Reports Server (NTRS)

    Blaauw, R. C.; Campbell-Brown, M. D.; Cooke, W.; Weryk, R. J.; Gill, J.; Musci, R.

    2013-01-01

    Within NASA, the Meteoroid Environment Office (MEO) is charged to monitor the meteoroid environment in near ]earth space for the protection of satellites and spacecraft. The MEO has recently established a two ]station system to calculate automated meteor fluxes in the millimeter ]size ]range. The cameras each consist of a 17 mm focal length Schneider lens on a Watec 902H2 Ultimate CCD video camera, producing a 21.7 x 16.3 degree field of view. This configuration has a red ]sensitive limiting meteor magnitude of about +5. The stations are located in the South Eastern USA, 31.8 kilometers apart, and are aimed at a location 90 km above a point 50 km equidistant from each station, which optimizes the common volume. Both single station and double station fluxes are found, each having benefits; more meteors will be detected in a single camera than will be seen in both cameras, producing a better determined flux, but double station detections allow for non ]ambiguous shower associations and permit speed/orbit determinations. Video from the cameras are fed into Linux computers running the ASGARD (All Sky and Guided Automatic Real ]time Detection) software, created by Rob Weryk of the University of Western Ontario Meteor Physics Group. ASGARD performs the meteor detection/photometry, and invokes the MILIG and MORB codes to determine the trajectory, speed, and orbit of the meteor. A subroutine in ASGARD allows for the approximate shower identification in single station meteors. The ASGARD output is used in routines to calculate the flux in units of #/sq km/hour. The flux algorithm employed here differs from others currently in use in that it does not assume a single height for all meteors observed in the common camera volume. In the MEO system, the volume is broken up into a set of height intervals, with the collecting areas determined by the radiant of active shower or sporadic source. The flux per height interval is summed to obtain the total meteor flux. As ASGARD also

  8. Meteor Search by Spirit, Sol 668

    NASA Technical Reports Server (NTRS)

    2005-01-01

    [figure removed for brevity, see original site] Annotated Meteor Search by Spirit, Sol 668

    The panoramic cameras on NASA's Mars Exploration Rovers are about as sensitive as the human eye at night. The cameras can see the same bright stars that we can see from Earth, and the same patterns of constellations dot the night sky. Scientists on the rover team have been taking images of some of these bright stars as part of several different projects. One project is designed to try to capture 'shooting stars,' or meteors, in the martian night sky. 'Meteoroids' are small pieces of comets and asteroids that travel through space and eventually run into a planet. On Earth, we can sometimes see meteoroids become brilliant, long 'meteors' streaking across the night sky as they burn up from the friction in our atmosphere. Some of these meteors survive their fiery flight and land on the surface (or in the ocean) where, if found, they are called 'meteorites.' The same thing happens in the martian atmosphere, and Spirit even accidentally discovered a meteor while attempting to obtain images of Earth in the pre-dawn sky back in March, 2004 (see http://marsrovers.jpl.nasa.gov/gallery/press/spirit/20040311a.html, and Selsis et al. (2005) Nature, vol 435, p. 581). On Earth, some meteors come in 'storms' or 'showers' at predictable times of the year, like the famous Perseid meteor shower in August or the Leonid meteor shower in November. These 'storms' happen when Earth passes through the same parts of space where comets sometimes pass. The meteors we see at these times are from leftover debris that was shed off of these comets.

    The same kind of thing is predicted for Mars, as well. Inspired by calculations about Martian meteor storms by meteor scientists from the University of Western Ontario in Canada and the Centre de Recherche en Astrophysique de Lyon in France, and also aided by other meteor research colleagues from NASA's Marshall Space Flight Center, scientists on

  9. Bright Meteor Lights Up Atlanta Skies

    NASA Video Gallery

    This video shows a very bright meteor that streaked over the skies of Atlanta, Ga., on the night of Aug. 28, 2011. The view is from an all sky camera in Cartersville, Ga., operated by NASA’s Mars...

  10. Lake Erie Fireball Meteor, Tavistock View

    NASA Video Gallery

    This brief video shows a view of the Aug 8 fireball meteor that entered the atmosphere 54 miles above Lake Erie and moved SSE at 25 km/s, or 55,900 mph. This view is from the all sky camera in Tavi...

  11. Lake Erie Fireball Meteor, Orangeville View

    NASA Video Gallery

    This brief video shows a view of the Aug 8 fireball meteor that entered the atmosphere 54 miles above Lake Erie and moved SSE at 25 km/s, or 55,900 mph. This view is from the all sky camera in Oran...

  12. Lake Erie Fireball Meteor, Mcmaster View

    NASA Video Gallery

    This brief video shows a view of the Aug 8 fireball meteor that entered the atmosphere 54 miles above Lake Erie and moved SSE at 25 km/s, or 55,900 mph. This view is from the all sky camera in Mcma...

  13. Enabling Agile Testing through Continuous Integration

    SciTech Connect

    Stolberg, Sean E.

    2009-08-24

    A Continuous Integration system is often considered one of the key elements involved in supporting an agile software development and testing environment. As a traditional software tester transitioning to an agile development environment it became clear to me that I would need to put this essential infrastructure in place and promote improved development practices in order to make the transition to agile testing possible. This experience report discusses a continuous integration implementation I lead last year. The initial motivations for implementing continuous integration are discussed and a pre and post-assessment using Martin Fowler's "Practices of Continuous Integration" is provided along with the technical specifics of the implementation. Finally, I’ll wrap up with a retrospective of my experiences implementing and promoting continuous integration within the context of agile testing.

  14. Participatory Design Activities and Agile Software Development

    NASA Astrophysics Data System (ADS)

    Kautz, Karlheinz

    This paper contributes to the studies of design activities in information systems development. It provides a case study of a large agile development project and focusses on how customers and users participated in agile development and design activities in practice. The investigated project utilized the agile method eXtreme Programming. Planning games, user stories and story cards, working software, and acceptance tests structured the customer and user involvement. We found genuine customer and user involvement in the design activities in the form of both direct and indirect participation in the agile development project. The involved customer representatives played informative, consultative, and participative roles in the project. This led to their functional empowerment— the users were enabled to carry out their work to their own satisfaction and in an effective, efficient, and economical manner.

  15. Multi-Year Radar Observations of Planetary Waves at High Conjugate Latitudes (Invited)

    NASA Astrophysics Data System (ADS)

    Fritts, D. C.; Iimura, H.; Janches, D.; Mitchell, N. J.; Singer, W.

    2013-12-01

    Meteor radars at nearly conjugate latitudes from ~54o to 68o S and N are enabling multi-year studies of planetary wave (PW) structure and seasonal, interannual, and inter-hemispheric variability. The various PWs exhibit dramatically different seasonal and inter-hemispheric variability, strongly variable amplitude and phase structures with altitude, latitude, and time, and episodic maxima in E-P flux components. This talk will review these features defined with meteor radars at Rothera Station and Ferraz Base (62 and 68 S), on Tierra del Fuego (54 S), and at Juliusruh, Germany and Esrange, Sweden (55 and 68 N).

  16. The Temporary factor in the Physical theory of meteor

    NASA Astrophysics Data System (ADS)

    Smirnov, V. A.

    The physical processes accompanying development of the meteor phenomenon, proceed in various temporary scales. For example, frequently meeting double final flares at meteors of a flow Perseid's occur in time, smaller 0,05 seconds. However, care of heat at the expense of energy of a driven meteor 1 gramme of substance for his evaporation needs time, on the order greater. Thus is explained significant inertness in movement of meteors and independence of light flares of meteor plasma of mechanical changes of structure of meteoroid's.

  17. Dormant comets among the near-Earth object population: a meteor-based survey

    NASA Astrophysics Data System (ADS)

    Ye, Quan-Zhi; Brown, Peter G.; Pokorný, Petr

    2016-11-01

    Dormant comets in the near-Earth object (NEO) population are thought to be involved in the terrestrial accretion of water and organic materials. Identification of dormant comets is difficult as they are observationally indistinguishable from their asteroidal counterparts, however, they may have produced dust during their final active stages which potentially are detectable today as weak meteor showers at the Earth. Here we present the result of a reconnaissance survey looking for dormant comets using 13 567 542 meteor orbits measured by the Canadian Meteor Orbit Radar (CMOR). We simulate the dynamical evolution of the hypothetical meteoroid streams originated from 407 near-Earth asteroids in cometary orbits that resemble orbital characteristics of Jupiter-family comets (JFCs). Out of the 44 hypothetical showers that are predicted to be detectable by CMOR, we identify five positive detections that are statistically unlikely to be chance associations, including three previously known associations. This translates to a lower limit to the dormant comet fraction of 2.0 ± 1.7 per cent in the NEO population and a dormancy rate of ˜10-5 yr-1 per comet. The low dormancy rate confirms disruption and dynamical removal as the dominant end state for near-Earth JFCs. We also predict the existence of a significant number of meteoroid streams whose parents have already been disrupted or dynamically removed.

  18. Comparison of TV magnitudes and visual magnitudes of meteors

    NASA Astrophysics Data System (ADS)

    Shigeno, Yoshihiko; Toda, Masayuki

    2008-08-01

    The generally accepted belief is that a meteor, with a large amount of infrared rays, can be captured brighter than it actually is by infrared-sensitive image intensifiers (I.I.) or CCD. We conducted observations of meteors using three methodologies: 1) I.I. with an attached filter that has the same spectral response as the human eye at night vision, 2) I.I. without the filter and 3) visually to determine meteor magnitudes. A total of 31 members of the astronomical club at Meiji University observed 50 Perseid meteors, 19 Geminid meteors as well as 44 sporadic meteors and the results were tabulated. The results helped us understand that on average I.I. can record meteors as brighter than visual observation by the magnitude equivalent of 0.5 for Perseids, 1.0 for Geminids and 0.5 for sporadic meteors. For I.I. with a filter that has the same spectral response the human eye at night vision, it turned out that we could obtain almost the same magnitude with observation by the human eye. We learned that a bright meteor with negative magnitude can be observed by I.I. brighter than the human eye. From several examples, we found I.I. could record a meteor with about -1 visual magnitude as brighter by about three magnitudes. We could probably do so because a bright meteor with negative magnitude may contain more infrared rays and the brightness could be amplified.

  19. Software ``Best'' Practices: Agile Deconstructed

    NASA Astrophysics Data System (ADS)

    Fraser, Steven

    Software “best” practices depend entirely on context - in terms of the problem domain, the system constructed, the software designers, and the “customers” ultimately deriving value from the system. Agile practices no longer have the luxury of “choosing” small non-mission critical projects with co-located teams. Project stakeholders are selecting and adapting practices based on a combina tion of interest, need and staffing. For example, growing product portfolios through a merger or the acquisition of a company exposes legacy systems to new staff, new software integration challenges, and new ideas. Innovation in communications (tools and processes) to span the growth and contraction of both information and organizations, while managing the adoption of changing software practices, is imperative for success. Traditional web-based tools such as web pages, document libraries, and forums are not suf ficient. A blend of tweeting, blogs, wikis, instant messaging, web-based confer encing, and telepresence creates a new dimension of communication “best” practices.

  20. Radar history

    NASA Astrophysics Data System (ADS)

    Putley, Ernest

    2008-07-01

    The invention of radar, as mentioned in Chris Lavers' article on warship stealth technology (March pp21-25), continues to be a subject of discussion. Here in Malvern we have just unveiled a blue plaque to commemorate the physicist Albert Percival Rowe, who arrived in 1942 as the head of the Telecommunications Research Establishment (TRE), which was the Air Ministry research facility responsible for the first British radar systems.

  1. Ground-based Optical Observations of Geophysical Phenomena: Aurora Borealis and Meteors

    NASA Astrophysics Data System (ADS)

    Samara, Marilia

    2010-10-01

    Advances in low-light level imaging technology have enabled significant improvements in the ground based study of geophysical phenomena. In this talk we focus on two such phenomena that occur in the Earth's ionosphere: aurorae and meteors. Imaging the aurora which is created by the interplay of the Earth's magnetosphere, ionosphere and atmosphere, provides a tool for remote sensing physical processes that are otherwise very difficult to study. By quantifying the intensities, scale sizes and lifetimes of auroral structures, we can gain significant insight into the physics behind the generation of the aurora and the interaction of the magnetosphere with the solar wind. Additionally, the combination of imaging with radars provides complimentary data and therefore more information than either method on its own. Meteor observations are a perfect example of this because the radar can accurately determine only the line-of-sight component of velocity, while imaging provides the direction of motion, the perpendicular velocity and brightness (a proxy for mass), therefore enabling a much more accurate determination of the full velocity vector and mass.

  2. The cometary and asteroidal origins of meteors

    NASA Technical Reports Server (NTRS)

    Kresak, L.

    1973-01-01

    A quantitative examination of the gravitational and nongravitational changes of orbits shows that for larger interplanetary bodies the perturbations by Jupiter strongly predominate over all other effects, which include perturbations by other planets, splitting of comet nuclei and jet effects of cometary ejections. The structure of meteor streams, indicates that the mutual compensation of the changes in individual elements entering the Jacobian integral, which is characteristic for the comets, does not work among the meteoroids. It appears that additional forces of a different kind must exert appreciable influence on the motion of interplanetary particles of meteoroid size. Nevertheless, the distribution of the Jacobian constant in various samples of meteor orbits furnishes some information on the type of their parent bodies and on the relative contribution of individual sources.

  3. The Swedish Allsky Meteor Network: first results

    NASA Astrophysics Data System (ADS)

    Stempels, E.; Kero, E.

    2016-01-01

    The Swedish Allsky Meteor Network started operations with two cameras in early 2014 and has since grown steadily. Currently, seven stations are active and several more will come online in the near future. The network to a large degree relies on low-cost stations run by private individuals or small societies of amateur astronomers. Originally based on the Danish meteor network Stjerneskud, the central node of Uppsala University provides the network with the necessary infrastructure, such as a continually updated software distribution and automatic processing of data from all stations. Although covering a very large land mass with relatively low resources is challenging, there have up to now been several well-observed events, often in collaboration with observations from neighboring countries. We give a short overview of the network's current status, chosen technical solutions, and some results.

  4. Data processing of records of meteoric echoes

    NASA Astrophysics Data System (ADS)

    Dolinský, P.

    2016-01-01

    The data obtained in the period from 4 November 2014 to 31 July 2014 by our receiving and recording system was statistically processed. The system records meteoric echoes from the TV transmitter Lviv 49.739583 MHz (N49.8480° E24.0369°, Ukraine) using a 4-element Yagi antenna with horizontal polarization (elevation of 0° and azimuth of 60°), receiver ICOM R-75 in the CW mode, and a computer with a recording using HROFFT v1.0.0f. The main goal was to identify weak showers in these data. Mayor or strong showers are visible without processing (referred at IMC2015, Mistelbach). To find or to identify weaker showers is more difficult. Not all echoes are meteoric echoes, but also ionospheric echoes or lightning disturbances are present.

  5. The World's Most Famous Meteor Shower Picture

    NASA Astrophysics Data System (ADS)

    Hughes, David W.

    1995-01-01

    The world's most famous meteor shower picture (Fig. 1) is of the storm that took place in the early morning of Wednesday, 13 November 1833. The picture was, however, produce 54 years after the event, being first published in April 1888. It had a biblical origin and was only taken over by the astronomers in the mid 1920s. The artist was the Swiss painter Karl Jauslin and the engraver was Adolf Völlmy.

  6. Elementary process and meteor train spectra

    NASA Technical Reports Server (NTRS)

    Ovezgeldyev, O. G.

    1987-01-01

    Mechanisms of excitation of individual spectral line radiation were studied experimentally and theoretically and it was demonstrated that such processes as oxidation, resonant charge exchange, dissociative recombination and others play an important part in the chemistry of excited particles. The foundation was laid toward simulating the elementary processes of meteor physics. Having a number of advantages and possibilities, this method is sure to find a wide use in the future.

  7. A global atmospheric model of meteoric iron

    NASA Astrophysics Data System (ADS)

    Feng, Wuhu; Marsh, Daniel R.; Chipperfield, Martyn P.; Janches, Diego; Höffner, Josef; Yi, Fan; Plane, John M. C.

    2013-08-01

    The first global model of meteoric iron in the atmosphere (WACCM-Fe) has been developed by combining three components: the Whole Atmosphere Community Climate Model (WACCM), a description of the neutral and ion-molecule chemistry of iron in the mesosphere and lower thermosphere (MLT), and a treatment of the injection of meteoric constituents into the atmosphere. The iron chemistry treats seven neutral and four ionized iron containing species with 30 neutral and ion-molecule reactions. The meteoric input function (MIF), which describes the injection of Fe as a function of height, latitude, and day, is precalculated from an astronomical model coupled to a chemical meteoric ablation model (CABMOD). This newly developed WACCM-Fe model has been evaluated against a number of available ground-based lidar observations and performs well in simulating the mesospheric atomic Fe layer. The model reproduces the strong positive correlation of temperature and Fe density around the Fe layer peak and the large anticorrelation around 100 km. The diurnal tide has a significant effect in the middle of the layer, and the model also captures well the observed seasonal variations. However, the model overestimates the peak Fe+concentration compared with the limited rocket-borne mass spectrometer data available, although good agreement on the ion layer underside can be obtained by adjusting the rate coefficients for dissociative recombination of Fe-molecular ions with electrons. Sensitivity experiments with the same chemistry in a 1-D model are used to highlight significant remaining uncertainties in reaction rate coefficients, and to explore the dependence of the total Fe abundance on the MIF and rate of vertical transport.

  8. SPA Meteor Section results: September - October, 1995.

    NASA Astrophysics Data System (ADS)

    McBeath, A.

    1996-04-01

    A compilation of visual, photographic and radio results submitted to the SPA Meteor Section from September and October is given. Although September was not an especially good month for observers, October brought a quite well-viewed Orionid return, enabling some magnitude and train details to be derived for the shower, and another brilliant fireball occurred at 2h28mUT on October 31.

  9. Structural peculiarities of the Quadrantid meteor shower

    NASA Technical Reports Server (NTRS)

    Isamutdinov, Sh. O.; Chebotarev, R. P.

    1987-01-01

    Systematic radio observations to investigate the Quadrantid meteor shower structure are regularly carried out. They have now been conducted annually in the period of its maximum activity, January 1 to 6, since 1966. The latest results of these investigations are presented, on the basis of 1981 to 1984 data obtained using new equipment with a limiting sensitivity of +7.7 sup m which make it possible to draw some conclusions on the Quadrantids shower structure both for transverse and lengthwise directions.

  10. A Global Atmospheric Model of Meteoric Iron

    NASA Technical Reports Server (NTRS)

    Feng, Wuhu; Marsh, Daniel R.; Chipperfield, Martyn P.; Janches, Diego; Hoffner, Josef; Yi, Fan; Plane, John M. C.

    2013-01-01

    The first global model of meteoric iron in the atmosphere (WACCM-Fe) has been developed by combining three components: the Whole Atmosphere Community Climate Model (WACCM), a description of the neutral and ion-molecule chemistry of iron in the mesosphere and lower thermosphere (MLT), and a treatment of the injection of meteoric constituents into the atmosphere. The iron chemistry treats seven neutral and four ionized iron containing species with 30 neutral and ion-molecule reactions. The meteoric input function (MIF), which describes the injection of Fe as a function of height, latitude, and day, is precalculated from an astronomical model coupled to a chemical meteoric ablation model (CABMOD). This newly developed WACCM-Fe model has been evaluated against a number of available ground-based lidar observations and performs well in simulating the mesospheric atomic Fe layer. The model reproduces the strong positive correlation of temperature and Fe density around the Fe layer peak and the large anticorrelation around 100 km. The diurnal tide has a significant effect in the middle of the layer, and the model also captures well the observed seasonal variations. However, the model overestimates the peak Fe+ concentration compared with the limited rocket-borne mass spectrometer data available, although good agreement on the ion layer underside can be obtained by adjusting the rate coefficients for dissociative recombination of Fe-molecular ions with electrons. Sensitivity experiments with the same chemistry in a 1-D model are used to highlight significant remaining uncertainties in reaction rate coefficients, and to explore the dependence of the total Fe abundance on the MIF and rate of vertical transport.

  11. Impact mechanics at Meteor Crater, Arizona

    USGS Publications Warehouse

    Shoemaker, Eugene Merle

    1959-01-01

    Meteor Crator is a bowl-shaped depression encompassed by a rim composed chiefly of debris stacked in layers of different composition. Original bedrock stratigraphy is preserved, inverted, in the debris. The debris rests on older disturbed strata, which are turned up at moderate to steep angles in the wall of the crater and are locally overturned near the contact with the debris. These features of Meteor Crater correspond closely to those of a crater produced by nuclear explosion where depth of burial of the device was about 1/5 the diameter of the resultant crater. Studies of craters formed by detonation of nuclear devices show that structures of the crater rims are sensitive to the depth of explosion scaled to the yield of the device. The structure of Meteor Crater is such as would be produced by a very strong shock originating about at the level of the present crater floor, 400 feet below the original surface. At supersonic to hypersonic velocity an impacting meteorite penetrates the ground by a complex mechanism that includes compression of the target rocks and the meteorite by shock as well as hydrodynamic flow of the compressed material under high pressure and temperature. The depth of penetration of the meteorite, before it loses its integrity as a single body, is a function primarily of the velocity and shape of the meteorite and the densities and equations of state of the meteorite and target. The intensely compressed material then becomes dispersed in a large volume of breccia formed in the expanding shock wave. An impact velocity of about 15 km/sec is consonant with the geology of Meteor Crater in light of the experimental equation of state of iron and inferred compressibility of the target rocks. The kinetic energy of the meteorite is estimated by scaling to have been from 1.4 to 1.7 megatons TNT equivalent.

  12. Long-Period Meteor Streams and the Dispersion of Semimajor Axes of Meteor Orbits

    NASA Astrophysics Data System (ADS)

    Hajduková, Mária, Jr.

    2013-06-01

    The present work is based on an analysis of a large statistical sample of meteor orbits collected in the Japanese shower catalogue (SonotaCo 2009, WGN, 37, 55) of 114280 video observed meteors. The shower meteor data were selected and analysed with the aim of determining the orbits' distribution in major meteor streams with heliocentric velocities close to the parabolic limit, in which the errors in the velocity determination correspond to large differences in the reciprocal semimajor axis, 1/a. The contribution of the real dispersion of the semimajor axes, a, can be deduced from the high proportion of hyperbolic orbits in the analysed streams, where an excess over the parabolic value can be regarded as being entirely due to measurement errors. The orbital dispersion described by the median absolute deviation in terms of 1/a was found to be ±0.083 AU-1 for the Leonids and ±0.080 AU-1 for the Orionids, and slightly smaller for the Perseid and Lyrid meteor streams (±0.055 and ±0.047 AU-1). The proximity of the parabolic limit caused a strong influence of observational effects; however, a significant contribution of the real dispersion is involved.

  13. Photometric stellar catalogue for TV meteor astronomy

    NASA Astrophysics Data System (ADS)

    Leonov, V. A.; Bagrov, A. V.

    2016-01-01

    Photometry for ordinary astrophysics was carefully developed for its own purposes. As stars radiation is very similar to the blackbody radiation, astronomers measure star illumination in wide or narrow calibrated spectral bands. This is enough for star photometry with precise accuracy and for measuring their light flux in these bands in energetic units. Meteors are moving objects and do not allow collection of more photons then they emit. So meteor observers use the whole spectral band that can be covered by sensitivity of their light sensors. This is why measurements of stellar magnitudes of background stars by these sensors are not the same as catalogued star brightness in standard photometric spectral bands. Here we present a special photometric catalogue of 93 bright non-variable stars of the northern hemisphere, that can be used by meteor observers of standard background whose brightness are calculated in energetic units as well as in non-systematic stellar magnitudes in spectral wavelength of the WATEC 902 sensitivity.

  14. Comet outbursts and the meteor showers

    NASA Astrophysics Data System (ADS)

    Guliyev, A. S.; Kokhirova, G. I.; Poladova, U. D.

    2014-07-01

    The features of 116 comets that have shown an outbursts in their brightness, are considered in the paper. The hypothesis on that the outburst in activity of comets are caused by their passing through meteoroid streams is studied. For this purpose the orbital elements of such comets relative to the planes of motion of 68 meteor showers from Cook's catalogue are analyzed. It was found that four of the nearest and distant nodes of comet orbits relative to the planes of motion of nine meteor showers exceeds the average statistical background with confidence probability from 0.90 to 0.95, and more than 0.95, respectively. The October Draconids, Aurigids, kappa-Serpentids, delta-Draconids, sigma-Hydrids}, Coma Berenicids, Leonids, Leo Minorids, and Perseids showers are the most effective. The results of calculation show that often, the comets outbursts may be caused by collisions of comets with meteoroids under the passing through the meteoroid streams that are producing listed meteor showers as well as solar activity.

  15. JEM-EUSO: Meteor and nuclearite observations

    NASA Astrophysics Data System (ADS)

    Adams, J. H.; Ahmad, S.; Albert, J.-N.; Allard, D.; Anchordoqui, L.; Andreev, V.; Anzalone, A.; Arai, Y.; Asano, K.; Ave Pernas, M.; Baragatti, P.; Barrillon, P.; Batsch, T.; Bayer, J.; Bechini, R.; Belenguer, T.; Bellotti, R.; Belov, K.; Berlind, A. A.; Bertaina, M.; Biermann, P. L.; Biktemerova, S.; Blaksley, C.; Blanc, N.; Błȩcki, J.; Blin-Bondil, S.; Blümer, J.; Bobik, P.; Bogomilov, M.; Bonamente, M.; Briggs, M. S.; Briz, S.; Bruno, A.; Cafagna, F.; Campana, D.; Capdevielle, J.-N.; Caruso, R.; Casolino, M.; Cassardo, C.; Castellinic, G.; Catalano, C.; Catalano, G.; Cellino, A.; Chikawa, M.; Christl, M. J.; Cline, D.; Connaughton, V.; Conti, L.; Cordero, G.; Crawford, H. J.; Cremonini, R.; Csorna, S.; Dagoret-Campagne, S.; de Castro, A. J.; De Donato, C.; de la Taille, C.; De Santis, C.; del Peral, L.; Dell'Oro, A.; De Simone, N.; Di Martino, M.; Distratis, G.; Dulucq, F.; Dupieux, M.; Ebersoldt, A.; Ebisuzaki, T.; Engel, R.; Falk, S.; Fang, K.; Fenu, F.; Fernández-Gómez, I.; Ferrarese, S.; Finco, D.; Flamini, M.; Fornaro, C.; Franceschi, A.; Fujimoto, J.; Fukushima, M.; Galeotti, P.; Garipov, G.; Geary, J.; Gelmini, G.; Giraudo, G.; Gonchar, M.; González Alvarado, C.; Gorodetzky, P.; Guarino, F.; Guzmán, A.; Hachisu, Y.; Harlov, B.; Haungs, A.; Hernández Carretero, J.; Higashide, K.; Ikeda, D.; Ikeda, H.; Inoue, N.; Inoue, S.; Insolia, A.; Isgrò, F.; Itow, Y.; Joven, E.; Judd, E. G.; Jung, A.; Kajino, F.; Kajino, T.; Kaneko, I.; Karadzhov, Y.; Karczmarczyk, J.; Karus, M.; Katahira, K.; Kawai, K.; Kawasaki, Y.; Keilhauer, B.; Khrenov, B. A.; Kim, J.-S.; Kim, S.-W.; Kim, S.-W.; Kleifges, M.; Klimov, P. A.; Kolev, D.; Kreykenbohm, I.; Kudela, K.; Kurihara, Y.; Kusenko, A.; Kuznetsov, E.; Lacombe, M.; Lachaud, C.; Lee, J.; Licandro, J.; Lim, H.; López, F.; Maccarone, M. C.; Mannheim, K.; Maravilla, D.; Marcelli, L.; Marini, A.; Martinez, O.; Masciantonio, G.; Mase, K.; Matev, R.; Medina-Tanco, G.; Mernik, T.; Miyamoto, H.; Miyazaki, Y.; Mizumoto, Y.; Modestino, G.; Monaco, A.; Monnier-Ragaigne, D.; Morales de los Ríos, J. A.; Moretto, C.; Morozenko, V. S.; Mot, B.; Murakami, T.; Murakami, M. Nagano; Nagata, M.; Nagataki, S.; Nakamura, T.; Napolitano, T.; Naumov, D.; Nava, R.; Neronov, A.; Nomoto, K.; Nonaka, T.; Ogawa, T.; Ogio, S.; Ohmori, H.; Olinto, A. V.; Orleański, P.; Osteria, G.; Panasyuk, M. I.; Parizot, E.; Park, I. H.; Park, H. W.; Pastircak, B.; Patzak, T.; Paul, T.; Pennypacker, C.; Perez Cano, S.; Peter, T.; Picozza, P.; Pierog, T.; Piotrowski, L. W.; Piraino, S.; Plebaniak, Z.; Pollini, A.; Prat, P.; Prévôt, G.; Prieto, H.; Putis, M.; Reardon, P.; Reyes, M.; Ricci, M.; Rodríguez, I.; Rodríguez Frías, M. D.; Ronga, F.; Roth, M.; Rothkaehl, H.; Roudil, G.; Rusinov, I.; Rybczyński, M.; Sabau, M. D.; Sáez-Cano, G.; Sagawa, H.; Saito, A.; Sakaki, N.; Sakata, M.; Salazar, H.; Sánchez, S.; Santangelo, A.; Santiago Crúz, L.; Sanz Palomino, M.; Saprykin, O.; Sarazin, F.; Sato, H.; Sato, M.; Schanz, T.; Schieler, H.; Scotti, V.; Segreto, A.; Selmane, S.; Semikoz, D.; Serra, M.; Sharakin, S.; Shibata, T.; Shimizu, H. M.; Shinozaki, K.; Shirahama, T.; Siemieniec-Oziȩbło, G.; Silva López, H. H.; Sledd, J.; Słomińska, K.; Sobey, A.; Sugiyama, T.; Supanitsky, D.; Suzuki, M.; Szabelska, B.; Szabelski, J.; Tajima, F.; Tajima, N.; Tajima, T.; Takahashi, Y.; Takami, H.; Takeda, M.; Takizawa, Y.; Tenzer, C.; Tibolla, O.; Tkachev, L.; Tokuno, H.; Tomida, T.; Tone, N.; Toscano, S.; Trillaud, F.; Tsenov, R.; Tsunesada, Y.; Tsuno, K.; Tymieniecka, T.; Uchihori, Y.; Unger, M.; Vaduvescu, O.; Valdés-Galicia, J. F.; Vallania, P.; Valore, L.; Vankova, G.; Vigorito, C.; Villaseñor, L.; von Ballmoos, P.; Wada, S.; Watanabe, J.; Watanabe, S.; Watts, J.; Weber, M.; Weiler, T. J.; Wibig, T.; Wiencke, L.; Wille, M.; Wilms, J.; Włodarczyk, Z.; Yamamoto, T.; Yamamoto, Y.; Yang, J.; Yano, H.; Yashin, I. V.; Yonetoku, D.; Yoshida, K.; Yoshida, S.; Young, R.; Zotov, M. Yu.; Zuccaro Marchi, A.

    2015-11-01

    Meteor and fireball observations are key to the derivation of both the inventory and physical characterization of small solar system bodies orbiting in the vicinity of the Earth. For several decades, observation of these phenomena has only been possible via ground-based instruments. The proposed JEM-EUSO mission has the potential to become the first operational space-based platform to share this capability. In comparison to the observation of extremely energetic cosmic ray events, which is the primary objective of JEM-EUSO, meteor phenomena are very slow, since their typical speeds are of the order of a few tens of km/sec (whereas cosmic rays travel at light speed). The observing strategy developed to detect meteors may also be applied to the detection of nuclearites, which have higher velocities, a wider range of possible trajectories, but move well below the speed of light and can therefore be considered as slow events for JEM-EUSO. The possible detection of nuclearites greatly enhances the scientific rationale behind the JEM-EUSO mission.

  16. Gamma-ray Astrophysics with AGILE

    SciTech Connect

    Longo, Francesco |; Tavani, M.; Barbiellini, G.; Argan, A.; Basset, M.; Boffelli, F.; Bulgarelli, A.; Caraveo, P.; Cattaneo, P.; Chen, A.; Costa, E.; Del Monte, E.; Di Cocco, G.; Di Persio, G.; Donnarumma, I.; Feroci, M.; Fiorini, M.; Foggetta, L.; Froysland, T.; Frutti, M.

    2007-07-12

    AGILE will explore the gamma-ray Universe with a very innovative instrument combining for the first time a gamma-ray imager and a hard X-ray imager. AGILE will be operational in spring 2007 and it will provide crucial data for the study of Active Galactic Nuclei, Gamma-Ray Bursts, unidentified gamma-ray sources. Galactic compact objects, supernova remnants, TeV sources, and fundamental physics by microsecond timing. The AGILE instrument is designed to simultaneously detect and image photons in the 30 MeV - 50 GeV and 15 - 45 keV energy bands with excellent imaging and timing capabilities, and a large field of view covering {approx} 1/5 of the entire sky at energies above 30 MeV. A CsI calorimeter is capable of GRB triggering in the energy band 0.3-50 MeV AGILE is now (March 2007) undergoing launcher integration and testing. The PLSV launch is planned in spring 2007. AGILE is then foreseen to be fully operational during the summer of 2007.

  17. Fighter agility metrics. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Liefer, Randall K.

    1990-01-01

    Fighter flying qualities and combat capabilities are currently measured and compared in terms relating to vehicle energy, angular rates and sustained acceleration. Criteria based on these measurable quantities have evolved over the past several decades and are routinely used to design aircraft structures, aerodynamics, propulsion and control systems. While these criteria, or metrics, have the advantage of being well understood, easily verified and repeatable during test, they tend to measure the steady state capability of the aircraft and not its ability to transition quickly from one state to another. Proposed new metrics to assess fighter aircraft agility are collected and analyzed. A framework for classification of these new agility metrics is developed and applied. A complete set of transient agility metrics is evaluated with a high fidelity, nonlinear F-18 simulation. Test techniques and data reduction methods are proposed. A method of providing cuing information to the pilot during flight test is discussed. The sensitivity of longitudinal and lateral agility metrics to deviations from the pilot cues is studied in detail. The metrics are shown to be largely insensitive to reasonable deviations from the nominal test pilot commands. Instrumentation required to quantify agility via flight test is also considered. With one exception, each of the proposed new metrics may be measured with instrumentation currently available.

  18. High-resolution radar observations of meteoroid fragmentation and flaring at the Jicamarca Radio Observatory

    NASA Astrophysics Data System (ADS)

    Zhu, Qian; Dinsmore, Ross; Gao, Boyi; Mathews, John D.

    2016-04-01

    Although meteoroid fragmentation has been observed and studied in the optical meteor community since the 1950s, no definitive fragmentation mechanisms for the relatively small meteoroids (mass ≲10-4 kg) have been proposed. This is in part due to the lack of observations to constrain physical models of the fragmentation process. While it is challenging to record fragmentation in faint optical meteors, observing faint meteors using High-Power, Large-Aperture coherent radars can yield considerable micrometeoroid fragmentation information especially when employing interferometric imaging. Radar interferometric imaging can potentially resolve the fragmentation process in three spatial dimensions by monitoring the evolution of the plasma in the meteor head-echo, flare-echo, and trail-echo regions. We present results of applying a newly developed hybrid interferometric-CS (compressed sensing) technique (H-ICS) to radar meteor observations conducted at the Jicamarca Radio Observatory in Peru. With the H-ICS technique - which provides improved spatial resolution over earlier techniques - we analyse five representative meteoroid fragmentation events. Results include observations of both along and transverse to the trajectory spreading of the developing plasma apparently caused by gross fragmentation and plasma diffusion parallel to the geomagnetic field near the geomagnetic equator.

  19. Analysis of Historical Meteor and Meteor shower Records: Korea, China and Japan

    NASA Astrophysics Data System (ADS)

    Yang, Hong-Jin; Park, Changbom; Park, Myeong-Gu

    2015-03-01

    We have compiled and analyzed historical meter and meteor shower records in Korean, Chinese, and Japanese chronicles. We have confirmed the peaks of Perseids and an excess due to the mixture of Orionids, north-Taurids, or Leonids through the Monte-Carlo test from the Korean records. The peaks persist for almost one thousand years. We have also analyzed seasonal variation of sporadic meteors from Korean records. Major features in Chinese meteor shower records are quite consistent with those of Korean records, particularly for the last millennium. Japanese records also show Perseids feature and Orionids/north-Taurids/Leonids feature, although they are less prominent compared to those of Korean or Chinese records.

  20. Contribution of Agility to Successful Distributed Software Development

    NASA Astrophysics Data System (ADS)

    Sarker, Saonee; Munson, Charles L.; Sarker, Suprateek; Chakraborty, Suranjan

    In recent times, both researchers and practitioners have touted agility as the latest innovation in distributed software development (DSD). In spite of this acknowledgement, there is little understanding and evidence surrounding the effect of agility on distributed project success. This chapter reports on a study that examines practitioner views surrounding the relative importance of different sub-types of agility to DSD project success. Preliminary results indicate that practitioners view on-time completion of DSD projects, and effective collaboration amongst stakeholders as the top two criteria of DSD project success, with lower emphasis on within-budget considerations. Among the many agility sub-types examined, people-based agility, communication-based agility, methodological agility, and time-based agility emerged as the most important for practitioners in terms of ensuring DSD project success.

  1. An investigation of fighter aircraft agility

    NASA Technical Reports Server (NTRS)

    Valasek, John; Downing, David R.

    1993-01-01

    This report attempts to unify in a single document the results of a series of studies on fighter aircraft agility funded by the NASA Ames Research Center, Dryden Flight Research Facility and conducted at the University of Kansas Flight Research Laboratory during the period January 1989 through December 1993. New metrics proposed by pilots and the research community to assess fighter aircraft agility are collected and analyzed. The report develops a framework for understanding the context into which the various proposed fighter agility metrics fit in terms of application and testing. Since new metrics continue to be proposed, this report does not claim to contain every proposed fighter agility metric. Flight test procedures, test constraints, and related criteria are developed. Instrumentation required to quantify agility via flight test is considered, as is the sensitivity of the candidate metrics to deviations from nominal pilot command inputs, which is studied in detail. Instead of supplying specific, detailed conclusions about the relevance or utility of one candidate metric versus another, the authors have attempted to provide sufficient data and analyses for readers to formulate their own conclusions. Readers are therefore ultimately responsible for judging exactly which metrics are 'best' for their particular needs. Additionally, it is not the intent of the authors to suggest combat tactics or other actual operational uses of the results and data in this report. This has been left up to the user community. Twenty of the candidate agility metrics were selected for evaluation with high fidelity, nonlinear, non real-time flight simulation computer programs of the F-5A Freedom Fighter, F-16A Fighting Falcon, F-18A Hornet, and X-29A. The information and data presented on the 20 candidate metrics which were evaluated will assist interested readers in conducting their own extensive investigations. The report provides a definition and analysis of each metric; details

  2. SuperAGILE and Gamma Ray Bursts

    SciTech Connect

    Pacciani, Luigi; Costa, Enrico; Del Monte, Ettore; Donnarumma, Immacolata; Evangelista, Yuri; Feroci, Marco; Frutti, Massimo; Lazzarotto, Francesco; Lapshov, Igor; Rubini, Alda; Soffitta, Paolo; Tavani, Marco; Barbiellini, Guido; Mastropietro, Marcello; Morelli, Ennio; Rapisarda, Massimo

    2006-05-19

    The solid-state hard X-ray imager of AGILE gamma-ray mission -- SuperAGILE -- has a six arcmin on-axis angular resolution in the 15-45 keV range, a field of view in excess of 1 steradian. The instrument is very light: 5 kg only. It is equipped with an on-board self triggering logic, image deconvolution, and it is able to transmit the coordinates of a GRB to the ground in real-time through the ORBCOMM constellation of satellites. Photon by photon Scientific Data are sent to the Malindi ground station at every contact. In this paper we review the performance of the SuperAGILE experiment (scheduled for a launch in the middle of 2006), after its first onground calibrations, and show the perspectives for Gamma Ray Bursts.

  3. Meteoric water in metamorphic core complexes

    NASA Astrophysics Data System (ADS)

    Teyssier, Christian; Mulch, Andreas

    2015-04-01

    The trace of surface water has been found in all detachment shear zones that bound the Cordilleran metamorphic core complexes of North America. DeltaD values of mica fish in detachment mylonites demonstrate that these synkinematic minerals grew in the presence of meteoric water. Typically deltaD values are very negative (-120 to -160 per mil) corresponding to deltaD values of water that are < -100 per mil given the temperature of water-mica isotopic equilibration (300-500C). From British Columbia (Canada) to Nevada (USA) detachment systems bound a series of core complexes: the Thor-Odin, Valhalla, Kettle-Okanogan, Bitterroot -Anaconda, Pioneer, Raft River, Ruby Mountain, and Snake Range. The bounding shear zones range in thickness from ~100 m to ~1 km, and within the shear zones, meteoric water signature is recognized over 10s to 100s of meters beneath the detachment fault. The age of shearing ranges generally from Eocene in the N (~50-45 Ma) to Oligo-Miocene in the S (25-15 Ma). DeltaD water values derived from mica fish in shear zones are consistent with supradetachment basin records of the same age brackets and can be used for paleoaltimetry if coeval isotopic records from near sea level are available. Results show that a wave of topography (typically 4000-5000 m) developed from N to S along the Cordillera belt from Eocene to Miocene, accompanied by the propagation of extensional deformation and volcanic activity. In addition, each detachment system informs a particular extensional detachment process. For example, the thick Thor-Odin detachment shear zone provides sufficient age resolution to indicate the downward propagation of shearing and the progressive incorporation of footwall rocks into the hanging wall. The Kettle detachment provides a clear illustration of the dependence of fluid circulation on dynamic recrystallization processes. The Raft River system consists of a thick Eocene shear zone that was overprinted by Miocene shearing; channels of meteoric

  4. Explaining the Obvious - How Do You Teach Agile?

    NASA Astrophysics Data System (ADS)

    Lundh, Erik

    Agile is now a hot topic and many organizations decide on adopting “agile” without really knowing how and why. This workshop will explore how fresh and seasoned agile coaches teach traditional and novel agile concepts, by example, with discussions. All participants are invited to show and tell about agile with an audience of peers. It might be the fresh first time with an audience, or golden hits that served you well for years.

  5. Agile interferometry: a non-traditional approach

    NASA Astrophysics Data System (ADS)

    Riza, Nabeel A.; Yaqoob, Zahid

    2004-11-01

    A new approach called agile interferometry is introduced to attain interferometric information with high sensitivity and scenario-based intelligence. Compared to traditional interferometric techniques, the proposed method thrives on dynamic control of the reference signal strength and detector integration time for efficient interferometric detection with high signal-to-noise ratio and significantly improved detected signal dynamic range capabilities. Theoretical analysis is presented with the operational methodology of the new approach. A high-speed optical attenuator is required in the interferometer reference arm to implement the proposed agile interferometer.

  6. Control design for future agile fighters

    NASA Technical Reports Server (NTRS)

    Murphy, Patrick C.; Davidson, John B.

    1991-01-01

    The CRAFT control design methodology is presented. CRAFT stands for the design objectives addressed, namely, Control power, Robustness, Agility, and Flying Qualities Tradeoffs. The approach combines eigenspace assignment, which allows for direct specification of eigenvalues and eigenvectors, and a graphical approach for representing control design metrics that captures numerous design goals in one composite illustration. The methodology makes use of control design metrics from four design objective areas, namely, control power, robustness, agility, and flying qualities. An example of the CRAFT methodology as well as associated design issues are presented.

  7. On the origin of ringing irregularities - A meteor hypothesis

    NASA Technical Reports Server (NTRS)

    Deshpande, M. R.; Vats, H. O.; Trivedi, A. I.

    1978-01-01

    Isolated ionospheric irregularities produce oscillating diffraction patterns on the ground. In the present study typical physical properties such as density, size, etc. of these irregularities are estimated on the basis of diffraction pattern characteristics. These properties agree well with those of meteor trail ionization and it has been found that most of these oscillating irregularities occur on meteor shower days. It is therefore suggested that the oscillating irregularities are caused by meteor showers.

  8. Influence of the meteoric stream on weather conditions: preliminary consideration

    NASA Astrophysics Data System (ADS)

    Granitskii, Lev V.; Borisevich, A. N.

    2000-12-01

    By the some estimation, about 150 tons of the meteoric matter are fall on the Earth every day. Some researchers note coincidence of the periods of activity of the most powerful meteoric stream with the periods of intensive falling of atmospheric precipitation. The unique meteoric stream Leonids represents the great interest as an example of possible correlation between meteors and power precipitation. The comet produced this stream is well known as Tempel-Tuttl comet, its orbital period is 33.3 years. With the same periodicity, the sharp strengthening of activity of a stream, which is called meteoric shower, is observed. Such meteoric stream during a night could cover the average monthly norm of fall of meteoric bodies at once in tens time. The analysis of meteorological data shows, that the winters of 1933, 1966, 1998 and 1999 years of a maximum Leonids activity are characterized by huge amount of snow. These anomalies have resulted in disasters in some of region. Under our suggestions, the anomaly rate of falling precipitation can be explained by the meteoric dust, which plays the role of the nucleuses of condensation. Thus, taking in to account the dada of regular meteoric stream, it's possible to make long term weather forecasting with the more preciseness.

  9. The Orionid Meteor Shower Observed Over 70 Years

    NASA Astrophysics Data System (ADS)

    Rendtel, Jürgen

    2008-06-01

    Visual Orionid meteor data dating back to 1944 were transformed into the standard format of the Visual Meteor Data Base (VMDB) of the International Meteor Organization (IMO) for systematic analysis. The strong 2006 Orionid return with a very low population index ( r = 1.6) and a peak ZHR of 60 (about 2.5 of the average peak strength) resembled meteor showers connected with the returns of resonant meteoroids. An investigation of data dating back to 1928 yielded similar rate enhancements in 1936, further supporting the assumption that meteoroids trapped in the 1:6 resonance with Jupiter caused the unusual 2006 Orionid return.

  10. Results of the IMO Video Meteor Network - December 2014

    NASA Astrophysics Data System (ADS)

    Molau, Sirko; Kac, Javor; Crivello, Stefano; Stomeo, Enrico; Barentsen, Geert; Goncalves, Rui; Saraiva, Carlos; Maciewski, Maciej; Maslov, Mikhail

    2015-04-01

    In 2014 December, 85 cameras of the IMO Video Meteor Network recorded almost 45 000 meteors in over 9 300 hours of observing time. The flux density profile is presented for the Geminids, as well as the population index profile around the maximum. A short-lasting outburst of the Ursids occurred on 2014 December 23 at 0h UT that reached a flux density of 60 meteoroids per 1 000 km^2 per hour in a 30-minute interval. The annual summary of the 2014 IMO Video Meteor Network observations is presented. More than 367 000 meteors were recorded in almost 100 000 hours of observing time.

  11. Results of the IMO Video Meteor Network - December 2015

    NASA Astrophysics Data System (ADS)

    Molau, S.; Crivello, S.; Goncalves, R.; Saraiva, C.; Stomeo, E.; Kac, J.

    2016-04-01

    In 2015 December, 80 cameras of the IMO Video Meteor Network recorded over 60 000 meteors in more than 10 600 hours of observing time. The flux density profile is presented for the Geminids and compared to previous years. The population index profile of the Geminids is also presented. The activity of the Ursids was slightly enhanced again. The flux density profile is presented and compared to profiles since 2011. The annual summary of the 2015 IMO Video Meteor Network observations is presented. More than 480 000 meteors were recorded in almost 122 000 hours of observing time.

  12. Spectral analysis of a high-velocity meteor

    NASA Technical Reports Server (NTRS)

    Harvey, G. A.

    1977-01-01

    A spectrogram of a fast optical meteor was reduced and analyzed, and 60 features were identified in the spectrum. Air and ionized elements in this meteor radiate throughout the spectrum from 3000 A to 6800 A. A mass of 9 mg and an effective radiation temperature of approximately 5700 K were computed for the meteor. Weight ratios of Ca:Fe, and Mg:Fe, and Na:Fe were computed. A plasma particle velocity distribution for meteors was derived, and the average collision speed obtained from this distribution was compared with the relative collision speed of a Fe-N2 gas mixture at 5700 K.

  13. METEOR - an artificial intelligence system for convective storm forecasting

    SciTech Connect

    Elio, R.; De haan, J.; Strong, G.S.

    1987-03-01

    An AI system called METEOR, which uses the meteorologist's heuristics, strategies, and statistical tools to forecast severe hailstorms in Alberta, is described, emphasizing the information and knowledge that METEOR uses to mimic the forecasting procedure of an expert meteorologist. METEOR is then discussed as an AI system, emphasizing the ways in which it is qualitatively different from algorithmic or statistical approaches to prediction. Some features of METEOR's design and the AI techniques for representing meteorological knowledge and for reasoning and inference are presented. Finally, some observations on designing and implementing intelligent consultants for meteorological applications are made. 7 references.

  14. Evidence of Meteoroid Fragmentation in Specular Trail Echoes Observed Using Gadanki MST Radar

    NASA Astrophysics Data System (ADS)

    Patil, A.; Malhotra, A.; Patra, A. K.; Prasad, T. R.; Mathews, J. D.

    2015-02-01

    Meteoroids are responsible for deposition of thousands of kilograms of annual mass flux in the Earth's upper atmosphere but the disintegration mechanisms of these bodies, and hence their composition, still remains a subject of debate in the meteor radar community. The role and significance of fragmentation as a meteoroid disintegration mechanism has been of particular interest in the past few years but in contrast to the head echoes, relatively little work has been done to study the effect and extent of fragmentation on trail echoes observed by the high power large aperture radars. Using the 53 MHz Gadanki MST radar, we present examples of radar meteor trails whose evolution cannot be explained with just the aid of classical meteor ablation theory. These examples are analyzed and discussed on a case-by-case basis and it is reported that the evolution of these trails can be explained with the help of fragmentation. This study will form the basis for future modeling efforts of fragmenting meteor trails and has important implications on the form in which the meteoroid mass is deposited in the upper atmosphere.

  15. Planetary radar

    NASA Technical Reports Server (NTRS)

    Taylor, R. M.

    1980-01-01

    The radar astronomy activities supported by the Deep Space Network during June, July, and August 1980 are reported. The planetary bodies observed were Venus, Mercury, and the asteroid Toro. Data were obtained at both S and X band, and the observations were considered successful.

  16. A Global Model of Meteoric Sodium

    NASA Technical Reports Server (NTRS)

    Marsh, Daniel R.; Janches, Diego; Feng, Wuhu; Plane, John M. C.

    2013-01-01

    A global model of sodium in the mesosphere and lower thermosphere has been developed within the framework of the National Center for Atmospheric Research's Whole Atmosphere Community Climate Model (WACCM). The standard fully interactive WACCM chemistry module has been augmented with a chemistry scheme that includes nine neutral and ionized sodium species. Meteoric ablation provides the source of sodium in the model and is represented as a combination of a meteoroid input function (MIF) and a parameterized ablation model. The MIF provides the seasonally and latitudinally varying meteoric flux which is modeled taking into consideration the astronomical origins of sporadic meteors and considers variations in particle entry angle, velocity, mass, and the differential ablation of the chemical constituents. WACCM simulations show large variations in the sodium constituents over time scales from days to months. Seasonality of sodium constituents is strongly affected by variations in the MIF and transport via the mean meridional wind. In particular, the summer to winter hemisphere flow leads to the highest sodium species concentrations and loss rates occurring over the winter pole. In the Northern Hemisphere, this winter maximum can be dramatically affected by stratospheric sudden warmings. Simulations of the January 2009 major warming event show that it caused a short-term decrease in the sodium column over the polar cap that was followed by a factor of 3 increase in the following weeks. Overall, the modeled distribution of atomic sodium in WACCM agrees well with both ground-based and satellite observations. Given the strong sensitivity of the sodium layer to dynamical motions, reproducing its variability provides a stringent test of global models and should help to constrain key atmospheric variables in this poorly sampled region of the atmosphere.

  17. Meteor orbit determination with improved accuracy

    NASA Astrophysics Data System (ADS)

    Dmitriev, Vasily; Lupovla, Valery; Gritsevich, Maria

    2015-08-01

    Modern observational techniques make it possible to retrive meteor trajectory and its velocity with high accuracy. There has been a rapid rise in high quality observational data accumulating yearly. This fact creates new challenges for solving the problem of meteor orbit determination. Currently, traditional technique based on including corrections to zenith distance and apparent velocity using well-known Schiaparelli formula is widely used. Alternative approach relies on meteoroid trajectory correction using numerical integration of equation of motion (Clark & Wiegert, 2011; Zuluaga et al., 2013). In our work we suggest technique of meteor orbit determination based on strict coordinate transformation and integration of differential equation of motion. We demonstrate advantage of this method in comparison with traditional technique. We provide results of calculations by different methods for real, recently occurred fireballs, as well as for simulated cases with a priori known retrieval parameters. Simulated data were used to demonstrate the condition, when application of more complex technique is necessary. It was found, that for several low velocity meteoroids application of traditional technique may lead to dramatically delusion of orbit precision (first of all, due to errors in Ω, because this parameter has a highest potential accuracy). Our results are complemented by analysis of sources of perturbations allowing to quantitatively indicate which factors have to be considered in orbit determination. In addition, the developed method includes analysis of observational error propagation based on strict covariance transition, which is also presented.Acknowledgements. This work was carried out at MIIGAiK and supported by the Russian Science Foundation, project No. 14-22-00197.References:Clark, D. L., & Wiegert, P. A. (2011). A numerical comparison with the Ceplecha analytical meteoroid orbit determination method. Meteoritics & Planetary Science, 46(8), pp. 1217

  18. Meteor Beliefs Project: Classical beliefs connecting meteors with life and death

    NASA Astrophysics Data System (ADS)

    McBeath, Alastair; Gheorghe, Andrei Dorian

    2006-10-01

    Details concerning meteors as indicators of life and death, extracted from ancient Greek and Latin sources between the circa 5th century BC to the circa 5th century AD, are presented. Some relevant material concerning souls as resident in stars in a similar vein is given too.

  19. Meteor Beliefs Project: some meteoric imagery in the works of William Shakespeare

    NASA Astrophysics Data System (ADS)

    McBeath, A.; Gheorghe, A. D.

    2003-08-01

    Passages from three of William Shakespeare's plays are presented, illustrating some of the beliefs in meteors in 16th-17th century England. They also reflect earlier beliefs and information which it is known Shakespeare drew on in constructing his works.

  20. Meteor Beliefs Project: Meteoric imagery associated with the death of John Brown in 1859

    NASA Astrophysics Data System (ADS)

    Drobnock, G. J.; McBeath, A.; Gheorghe, A. D.

    2009-12-01

    An examination is made of metaphorical meteor imagery used in conjunction with the death of American anti-slavery activist John Brown, who was executed in December 1859. Such imagery continues to be used in this regard into the 21st century.

  1. Present State and Prospects for the Meteor Research in Ukraine

    NASA Astrophysics Data System (ADS)

    Shulga, O.; Voloshchuk, Y.; Kolomiyets, S.; Cherkas, Y.; Kimakovskay, I.; Kimakovsky, S.; Knyazkova, E.; Kozyryev, Y.; Sybiryakova, Y.; Gorbanev, Y.; Stogneeva, I.; Shestopalov, V.; Kozak, P.; Rozhilo, O.; Taranukha, Y.

    2015-03-01

    ODESSA. Systematical study of the meteor events are being carried out since 1953. In 2003 complete modernization of the observing technique was performed, and TV gmeteor patrolh on the base of WATEC LCL902 cameras was created. @ wide variety of mounts and objectives are used: from Schmidt telescope F = 540 mm, F/D = 2.25 (field of view FOV = (0.68x0.51) deg, star limiting magnitude SLM = 13.5 mag, star astrometric accuracy 1-2 arcsec) up to Fisheye lenses F = 8 mm, F/D = 3.5 (FOV = (36x49) deg, SLM = 7 mag). The database of observations that was collected between 2003 and 2012 consists of 6176 registered meteor events. Observational programs on basis and non-basis observations in Odessa (Kryzhanovka station) and Zmeiny island are presented. Software suite of 12 programs was created for processing of meteor TV observations. It enables one to carry out the whole cycle of data processing: from image preprocessing up to orbital elements determination. Major meteor particles research directions: statistic, areas of streams, precise stream radiant, orbit elements, phenomena physics, flare appearance, wakes, afterglow, chemistry and density. KYIV. The group of meteor investigations has been functioning more than twenty years. The observations are carried out simultaneously from two points placed at the distance of 54 km. Super-isocon low light camera tubes are used with photo lens: F = 50mm, F/D = 1.5 (FOV = (23.5 x 19.0) deg, SLM = 9.5 mag), or F = 85, F/D = 1.5 (FOV = (13x11) deg, SLM = 11.5 mag). Astrometry, photometry, calculation of meteor trajectory in Earth atmosphere and computation of heliocentric orbit are realized in developed gFalling Starh software. KHARKOV. Meteor radio-observations have begun in 1957. In 1972, the radiolocation system MARS designed for automatic meteor registration was recognized as being the most sensitive system in the world. With the help of this system 250 000 faint meteors (up to 12 mag) were registered between 1972 and 1978 (frequency

  2. Aging comets and their meteor showers

    NASA Astrophysics Data System (ADS)

    Ye, Quan-Zhi

    2016-10-01

    Comets are thought to be responsible for the terrestrial accretion of water and organic materials. The aging of comets is one of the most critical yet poorly understood problems in planetary astronomy. Here we attack this problem by examining different parts of the cometary aging spectrum of Jupiter-family comets (JFCs), a group of comets that dominates the cometary influx in the near-Earth space, using both telescopic and meteor observations.We examine two representative JFCs and the population of dormant comets. At the younger end of the aging spectrum, we examine a moderately active JFC, 15P/Finlay, and review the puzzle of the non-detection of the associated Finlayid meteor shower. We find that, although having been behaved like a dying comet in the past several 102 years, 15P/Finlay does possess ability for energetic outbursts without a clear reason. Towards the more aged end of the spectrum, we examine a weakly active JFC, 209P/LINEAR. By bridging telescopic observations at visible and infrared wavelength, meteor observations and dynamical investigations, we find that 209P/LINEAR is indeed likely an aged yet long-lived comet. At the other end of the spectrum, we examine the population of dormant near-Earth comets, by conducting a comprehensive meteor-based survey looking for dormant comets that have recently been active. We find the lower limit of the dormant comet fraction in the near-Earth object (NEO) population to be 2.0 ± 1.7%. This number is at the lower end of the numbers found using dynamical and telescopic techniques, which may imply that a significant fraction of comets in the true JFC population are weakly active and are not yet detected.These results have revealed interesting diversities in dying or dead comets, both in their behaviors as well as their natures. An immediate quest in the understanding of cometary aging would be to examine a large number of dying or dead comets and understand their general characteristics.

  3. Analysis of photometric spectra of 17 meteors

    NASA Technical Reports Server (NTRS)

    Millman, P. M.

    1982-01-01

    The initial phase of the photometry which involved 17 meteor spectra consisting of eight Geminid spectra, six Orionid spectra and three Eta Aquarid spectra is discussed. Among these 17 spectra it is found that the Geminid spectra are of the best quality and are used for the identification of the atomic lines and molecular bands that normally appear on video tape spectra. The data from the Geminid records are used for developing calibration techniques in photometry. The Orionid and Eta Aquarid spectra are chosen for early analysis because of the current interest in all physical and chemical data relating to Comet Halley.

  4. 5th Annual AGILE Science Workshop

    NASA Technical Reports Server (NTRS)

    Hunter, Stanley

    2008-01-01

    The EGRET model of the galactic diffuse gamma-ray emission (GALDIF) has been extended to provide full-sky coverage and improved to address the discrepancies with the EGRET data. This improved model is compared with the AGILE results from the Galactic center. The comparison is discussed.

  5. Lean and Agile: An Epistemological Reflection

    ERIC Educational Resources Information Center

    Browaeys, Marie-Joelle; Fisser, Sandra

    2012-01-01

    Purpose: The aim of the paper is to contribute to the discussion of treating the concepts of lean and agile in isolation or combination by presenting an alternative view from complexity thinking on these concepts, considering an epistemological approach to this topic. Design/methodology/approach: The paper adopts an epistemological approach, using…

  6. Achieving agility through parameter space qualification

    SciTech Connect

    Diegert, K.V.; Easterling, R.G.; Ashby, M.R.; Benavides, G.L.; Forsythe, C.; Jones, R.E.; Longcope, D.B.; Parratt, S.W.

    1995-02-01

    The A-primed (Agile Product Realization of Innovative electro-Mechanical Devices) project is defining and proving processes for agile product realization for the Department of Energy complex. Like other agile production efforts reported in the literature, A-primed uses concurrent engineering and information automation technologies to enhance information transfer. A unique aspect of our approach to agility is the qualification during development of a family of related product designs and their production processes, rather than a single design and its attendant processes. Applying engineering principles and statistical design of experiments, economies of test and analytic effort are realized for the qualification of the device family as a whole. Thus the need is minimized for test and analysis to qualify future devices from this family, thereby further reducing the design-to-production cycle time. As a measure of the success of the A-primed approach, the first design took 24 days to produce, and operated correctly on the first attempt. A flow diagram for the qualification process is presented. Guidelines are given for implementation, based on the authors experiences as members of the A-primed qualification team.

  7. Comparison of a New Test For Agility and Skill in Soccer With Other Agility Tests

    PubMed Central

    Kutlu, Mehmet; Yapıcı, Hakan; Yoncalık, Oğuzhan; Çelik, Serkan

    2012-01-01

    The purpose of this study was both to develop a novel test to measure run, shuttle run and directional change agility, and soccer shots on goal with decision making and to compare it with other agility tests. Multiple comparisons and assessments were conducted, including test-retest, Illinois, Zig-Zag, 30 m, Bosco, T-drill agility, and Wingate peak power tests. A total of 113 Turkish amateur and professional soccer players and tertiary-level students participated in the study. Test-retest and inter-tester reliability testing measures were conducted with athletes. The correlation coefficient of the new test was .88, with no significant difference (p> 0.01> 0.01) between the test results obtained in the first and second test sessions. The results of an analysis of variance revealed a significant (p < 0.01) difference between the T-drill agility and power test results for soccer players. The new agility and skill test is an acceptable and reliable test when considering test-retest reliability and inter-rater reliability. The findings in this study suggest that the novel soccer-specific agility and shooting test can be utilized in the testing and identification of soccer players’ talents. PMID:23486732

  8. Radar Detectability Studies of Slow and Small Zodiacal Dust Cloud Particles: II. A Study of Three Radars with Different Sensitivity

    NASA Astrophysics Data System (ADS)

    Janches, D.; Swarnalingam, N.; Plane, J. M. C.; Nesvorný, D.; Feng, W.; Vokrouhlický, D.; Nicolls, M. J.

    2015-07-01

    The sensitivity of radar systems to detect different velocity populations of the incoming micrometeoroid flux is often the first argument considered to explain disagreements between models of the Near-Earth dust environment and observations. Recently, this was argued by Nesvorný et al. to support the main conclusions of a Zodiacal Dust Cloud (ZDC) model which predicts a flux of meteoric material into the Earth’s upper atmosphere mostly composed of small and very slow particles. In this paper, we expand on a new methodology developed by Janches et al. to test the ability of powerful radars to detect the meteoroid populations in question. In our previous work, we focused on Arecibo 430 MHz observations since it is the most sensitive radar that has been used for this type of observation to date. In this paper, we apply our methodology to two other systems, the 440 MHz Poker Flat Incoherent Scatter Radar and the 46.5 Middle and Upper Atmosphere radar. We show that even with the less sensitive radars, the current ZDC model over-predicts radar observations. We discuss our results in light of new measurements by the Planck satellite which suggest that the ZDC particle population may be characterized by smaller sizes than previously believed. We conclude that the solution to finding agreement between the ZDC model and sensitive high power and large aperture meteor observations must be a combination of a re-examination not only of our knowledge of radar detection biases, but also the physical assumptions of the ZDC model itself.

  9. A new radar technique for satellite rainfall algorithm development

    NASA Technical Reports Server (NTRS)

    Jameson, Arthur R.

    1987-01-01

    A potential new radar parameter was investigated for measuring rainfall, namely the summation of the phase shifts at horizontal and vertical polarizations due to propagation through precipitation. The proposed radar technique has several potential advantages over other approaches because it is insensitive to the drop size distribution and to the shapes of the raindrops. Such a parameter could greatly assist the development of satellite rainfall estimation algorithms by providing comparative measurements near the ground. It could also provide hydrologically useful information for such practical applications as urban hydrology. Results of the investigation showed that the parameters can not be measured by radar. However, a closely related radar parameter, propagation differential phase shift, can be readily measured using a polarization diversity radar. It is recommended that propagation differential phase shift be further investigated and developed for radar monitoring of rainfall using a polarization agile radar. It is also recommended that a prototype multiple frequency microwave link be constructed for attenuation measurements not possible by existing radar systems.

  10. AGILE and Gamma-Ray Bursts

    SciTech Connect

    Longo, Francesco; Tavani, M.; Barbiellini, G.; Argan, A.; Basset, M.; Boffelli, F.; Bulgarelli, A.; Caraveo, P.; Cattaneo, P.; Chen, A.; Costa, E.; Del Monte, E.; Di Cocco, G.; Di Persio, G.; Donnarumma, I.; Feroci, M.; Fiorini, M.; Foggetta, L.; Froysland, T.; Frutti, M.

    2006-05-19

    AGILE is a Scientific Mission dedicated to high-energy astrophysics supported by ASI with scientific participation of INAF and INFN. The AGILE instrument is designed to simultaneously detect and image photons in the 30 MeV - 50 GeV and 15 - 45 keV energy bands with excellent imaging and timing capabilities, and a large field of view covering {approx} 1/5 of the entire sky at energies above 30 MeV. A CsI calorimeter is capable of GRB triggering in the energy band 0.3-50 MeV. The broadband detection of GRBs and the study of implications for particle acceleration and high energy emission are primary goals of th emission. AGILE can image GRBs with 2-3 arcminutes error boxes in the hard X-ray range, and provide broadband photon-by photon detection in the 15-45 keV, 03-50 MeV, and 30 MeV-30 GeV energy ranges. Microsecond on-board photon tagging and a {approx} 100 microsecond gamma-ray detection deadtime will be crucial for fast GRB timing. On-board calculated GRB coordinates and energy fluxes will be quickly transmitted to the ground by an ORBCOMM transceiver. AGILE have recently (December 2005) completed its gamma-ray calibration. It is now (January 2006) undergoing satellite integration and testing. The PLSV launch is planned in early 2006. AGILE is then foreseen to be fully operational during the summer of 2006. It will be the only mission entirely dedicated to high-energy astrophysics above 30 MeV during the period mid-2006/mid-2007.

  11. Radar Detection of Interstellar Dust

    NASA Astrophysics Data System (ADS)

    Baggaley, J.

    2003-04-01

    As primordial building material of complexes like our own solar system, dust is centrally important in the evolution of such planetary systems. Circumstellar dust can be sensed associated with Young Stellar Objects, IR excess stars and forms the ejecta of red giants, carbon-rich stars and supernovae. Interstellar dust can be cumulatively sensed over astronomically long sight-lines by the extinction, scattering and polarisation of starlight. The direct detection of interstellar dust (ISD) particles flowing into the solar system is important because such observations can directly probe the local cloud interstellar dust environment and can sense discrete stellar sources. The Advanced Meteor Orbit Radar (AMOR) is a facility designed to measure the trajectories of dust impacting the Earth's atmosphere: the continuously operating radar is able to archive a large (˜ 10^6) data-base of dust trajectories and so is able to map the inflow directions of interstellar material into the solar system. Such Earth-based mapping of ISD dynamics complements the in-situ impact detections by space missions such as Ulysses and Stardust.

  12. Meteoroid Fragmentation as Revealed in Head- and Trail-Echoes Observed with the Arecibo UHF and VHF Radars

    NASA Technical Reports Server (NTRS)

    Mathews, J. D.; Malhorta, A.

    2011-01-01

    We report recent 46.8/430 MHz (VHF/UHF) radar meteor observations at Arecibo Observatory (AO) that reveal many previously unreported features in the radar meteor return - including flare-trails at both UHF and VHF - that are consistent with meteoroid fragmentation. Signature features of fragmentation include strong intra-pulse and pulse-to-pulse fading as the result of interference between or among multiple meteor head-echo returns and between head-echo and impulsive flare or "point" trail-echoes. That strong interference fading occurs implies that these scatterers exhibit well defined phase centers and are thus small compared with the wavelength. These results are consistent with and offer advances beyond a long history of optical and radar meteoroid fragmentation studies. Further, at AO, fragmenting and flare events are found to be a large fraction of the total events even though these meteoroids are likely the smallest observed by the major radars. Fragmentation is found to be a major though not dominate component of the meteors observed at other HPLA radars that are sensitive to larger meteoroids.

  13. Orbital evolution of Geminids and Quadrantids by middle and upper atmosphere radar observations

    NASA Astrophysics Data System (ADS)

    Abe, S.; Kero, J.; Nakamura, T.; Fujiwara, Y.; Watanabe, J.

    2014-07-01

    A meteor head echo is caused by radio waves scattering from the intense region of the plasma surrounding and co-moving with a meteoroid during atmospheric entry at about 70--130 km altitude. Meteor head echo observations were carried out using the high-power large-aperture (HPLA) Kyoto university Shigaraki middle and upper atmosphere (MU) radar in Japan (34.85° N, 136.10° E). The 46.5 MHz MU radar consisting of 475 crossed Yagi antennas has a nominal transmitter peak power of 1 MW and comprises a circular, phased-array antenna with a diameter of 103 m. The MU radar beam was pointed in the zenith direction with the field of view of ˜ 15°. Since 2009 the atmospheric trajectories and interplanetary orbital elements have been derived using the MU radar meteor head echoes (e.g. [1--3]). More than 140,000 sets of orbital elements of meteors were obtained until January 2014. Typical errors for velocity and perihelion distance are 0.25 km/s and 0.003 au, respectively. Such a huge number of meteoroid orbits with precise orbital accuracies has not been observed before. Here we report population of 2009--2013 Geminid and 2014 Quadrantid meteoroids. The orbits of Geminids' meteoroids, whose parent body is a comet-asteroid transition object (3200) Phaethon [4], were observed in 2009 (n=163), 2010 (n=310) and 2013 (n=513) whereas Quadrantids (n=223), whose parent body is 2003 EH_1 [5], were obtained in 2014. Figure shows radiant distributions (RA & DEC) and orbital elements (perihelion distance - eccentricity) of Geminids as a function of the Radar Cross Section (RCS) which is approximately a linear function of the log of electron line densities of a meteor trail corresponding to a meteoroid mass. The meteoroid orbital evolution of Geminids and Quadrantds considering Poynting-Robertson drag will be discussed compared with their parent bodies.

  14. Very Precise Orbits of 1998 Leonid Meteors

    NASA Technical Reports Server (NTRS)

    Betlem, Hans; Jenniskens, Peter; vantLeven, Jaap; terKuile, Casper; Johannink, Carl; Zhao, Hai-Bin; Lei, Chen-Ming; Li, Guan-You; Zhu, Jin; Evans, Steve; DeVincenzi, Donald L. (Technical Monitor)

    1999-01-01

    Seventy-five orbits of Leonid meteors obtained during the 1998 outburst are presented. Thirty-eight are precise enough to recognize significant dispersion in orbital elements. Results from the nights of 1998 November 16/17 and 17/18 differ, in agreement with the dominant presence of different dust components. The shower rate profile of 1998 November 16/17 was dominated by a broad component, rich in bright meteors. The radiant distribution is compact. The semimajor axis is confined to values close to that of the parent comet, whereas the distribution of inclination has a central condensation in a narrow range. On the other hand, 1998 November 17/18 was dominated by dust responsible for a more narrow secondary peak in the flux curve. The declination of the radiant and the inclination of the orbit are more widely dispersed. The argument of perihelion, inclination, and the perihelion distance are displaced. These data substantiate the hypothesis that trapping in orbital resonances is important for the dynamical evolution of the broad component.

  15. Meteoric Magnesium Ions in the Martian Atmosphere

    NASA Technical Reports Server (NTRS)

    Pesnell, William Dean; Grebowsky, Joseph

    1999-01-01

    From a thorough modeling of the altitude profile of meteoritic ionization in the Martian atmosphere we deduce that a persistent layer of magnesium ions should exist around an altitude of 70 km. Based on current estimates of the meteoroid mass flux density, a peak ion density of about 10(exp 4) ions/cm is predicted. Allowing for the uncertainties in all of the model parameters, this value is probably within an order of magnitude of the correct density. Of these parameters, the peak density is most sensitive to the meteoroid mass flux density which directly determines the ablated line density into a source function for Mg. Unlike the terrestrial case, where the metallic ion production is dominated by charge-exchange of the deposited neutral Mg with the ambient ions, Mg+ in the Martian atmosphere is produced predominantly by photoionization. The low ultraviolet absorption of the Martian atmosphere makes Mars an excellent laboratory in which to study meteoric ablation. Resonance lines not seen in the spectra of terrestrial meteors may be visible to a surface observatory in the Martian highlands.

  16. Investigation of meteor shower parent bodies using various metrics

    NASA Astrophysics Data System (ADS)

    Dumitru, B. A.; Birlan, M.; Nedelcu, A.; Popescu, M.

    2016-01-01

    The present knowledge of meteor showers identifies the small bodies of our Solar System as supply sources for meteor streams. Both comets and asteroids are considered as the origin of meteor showers. The new paradigm of "active asteroids" opens up a large field of investigation regarding the relationships between asteroids and meteors. Processes like ejection and disaggregation at impacts, rotational instabilities, electrostatic repulsion, radiation pressure, dehydration stress followed by thermal fractures, sublimation of ices are sources of matter loss from asteroids. Our objective is to find genetic relationships between asteroids and meteor showers using metrics based on orbital elements. For this objective we selected three metrics (Southworth and Hawkins, 1963; Asher et al. 1993, and Jopek, 1993, respectively), the recent MPC database and the more recent IAU meteor shower database. From our analysis, 41 of the meteor showers have probabilities of being produced (or to be fueled) by asteroids. Our sample of asteroids contains more than 1000 objects, all of them belonging to the Near-Earth Asteroid population. The systematic approach performed, based on the physical properties of our sample, reinforced the link between asteroids and their associated meteor shower.

  17. The motion of radio meteor reflection point of Geminids

    NASA Astrophysics Data System (ADS)

    Ohnishi, Kouji; Ishikawa, Toshiyuki; Hattori, Shinobu; Nishimura, Osamu; Miyazawa, Akiko; Yanagisawa, Masatoshi; Endo, Makoto; Kawamura, Masaki; Maruyama, Toshiyuki; Hosayama, Kai; Tokunaga, Mai; Maegawa, Kimio; Abe, Shinsuke

    2001-11-01

    Ham-band Radio Observation (HRO) is one of the observational techniques for the forward scatter observation of meteors. We observe the meteor echo with two-element loop antennas (F/B ratio is 10 dB) at the Nagano National College of Technology (Nagano, Japan) using the continuous transmission of beacon signals for meteor observations at 53.750 MHz, 50W from Fukui National College of Technology (Fukui, Japan). To prove that the radio echo is really the echo due to meteor, we have constructed the direction determination system using the paired antennas that can detect the direction roughly where the radio echo come from. The direction of one of this paired antennas was West toward Sabae and the other was East which has proved to be the most sensitive for this research. Using this system, we detected the change of the direction of reflection point of meteor radio signal of Geminids in 2000; from the westward to eastward before and after the culmination of the radiant which is consistent the formula of reflection point of meteors. At the same time, we detected the change of an intensity and a trend of the Doppler shift of meteor echoes. This result is consistent of the meteor wind data of MU Rader of Radio Science Center for Space & Atmosphere (RASC), Kyoto University.

  18. Don Quixote - a possible parent body of a meteor shower

    NASA Astrophysics Data System (ADS)

    Rudawska, Regina; Vaubaillon, Jérémie

    2014-02-01

    Here we are interested in whether the meteoroid stream of (3552) Don Quixote can generate some observed meteor showers. We have showed that particles originating from Don Quixote particles produce two meteor showers at Earth: Kappa Lyrids and August Mu Draconids.

  19. Meteor trails observed by the Sloan Digital Sky Survey

    NASA Astrophysics Data System (ADS)

    Cikota, A.; Bektešević, D.; Cikota, S.; Weaver, B.; Jevremović, D.; Vinković, D.

    2014-07-01

    Scientific observation of meteors is not simple because they have large angular size and random appearance in time and position on the sky. Bright meteors can be easily observed by naked eye or by video cameras in low resolution, but the luminosity distribution of meteors at their fainter end, the actual column diameter of the radiating zone, meteor fragmentation and the microstructure of lightcurves (especially when a meteor is detected through several color filters, as it happened in SDSS) is not well investigated. However, wide-field surveys, such as SDSS or the future LSST, with long time coverage over a significant fraction of sky might be helpful in collecting a scientifically relevant sample of low-brightness meteors. We used a custom designed Python script to detect linear features in SDSS images. The detection is performed in two steps: 1) we detect stars with Source Extractor [1] and blend them out; 2) we define a threshold so as to analyze 10000 points over the threshold; 3) we apply RANSAC [2] to detect points forming a line. We detected trails in over 15000 calibrated and sky-subtracted ''frame'' images in two filters so far. The drift scan in imaging survey mode of SDSS enables simple distinction between "apparently fast" meteors and other "slow" linear features caused by satellites and space debris, so that around 4000 frames could be eliminated as obvious satellites. Here we discuss the detection method, show some interesting preliminary results of the analysis of detected meteors, and discuss implications for other surveys.

  20. Goals, technique and equipment of meteor study in Russia

    NASA Astrophysics Data System (ADS)

    Kartashova, A.; Bagrov, A. V.; Bolgova, G. T.; Kruchkov, S. V.; Leonov, V. A.; Mazurov, V. A.

    2013-09-01

    Institute of Astronomy RAS is one of the science institutes in the Russian Federation providing systematic optical meteor observations and supervises several meteor groups in our country. The main tasks of our investigations are dedicated to study meteoroid nature as well as meteoroid streams and meteoroid population in the Solar System. In the XXI century we in Russia carry out the reconstruction of our meteor astronomy due to possibilities of new meteor observation equipment (more powerful than were used before as visual and photographic methods) had made possible to select more interesting goals. First of our task is investigation of meteoroid streams crossing the Earth's orbit, and character of meteoroid distributions along of them. The multi stations meteor monitoring from located in the both hemispheres of the Earth can help in this study. According to the analysis of the evolution of meteor orbits, the compact and long lived meteoroid streams consist mainly from large particles. The observation equipment (cheap TV-cameras) with low limiting magnitude we use for gathering observational data. On the other hand, the observations of weak meteors are needed for new meteor shower indication (or confirmation of known meteor shower). The more effective way to do it is comparison of individual meteor orbits parameters (then calculation of radiants of meteor showers). The observations of space debris (as the meteors with low velocity - less 11.2 km/s) can be taking up within this task. The combination of high sensitive TV-cameras WATEC and super-fast lenses COMPUTAR are widely used for meteor TV-monitoring. The TVsystems for round-year meteor observations are fixed and are permanently oriented to the zenith area (the patrol camera - PatrolCa). The mobile TV-cameras (MobileCa) are used for double station observations (if it is possible) and located not far from main cameras PatrolCa (20-30 km). The mobile TVcameras observe 90% of main PatrolCa cameras FOV at altitudes

  1. Abstracts for the International Conference on Asteroids, Comets, Meteors 1991

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Topics addressed include: chemical abundances; asteroidal belt evolution; sources of meteors and meteorites; cometary spectroscopy; gas diffusion; mathematical models; cometary nuclei; cratering records; imaging techniques; cometary composition; asteroid classification; radio telescopes and spectroscopy; magnetic fields; cosmogony; IUE observations; orbital distribution of asteroids, comets, and meteors; solar wind effects; computerized simulation; infrared remote sensing; optical properties; and orbital evolution.

  2. Quetelet and the Discovery of the First Meteor Showers

    NASA Astrophysics Data System (ADS)

    Sauval, J.

    1997-02-01

    The contribution of Adolphe Quetelet to meteor astronomy is important. In 1836 he predicted the return of the Perseids and in 1837 he published the first catalogue of meteors. He was also an independent co-discoverer of the Orionids and the Quadrantids in 1839.

  3. Meteor Showers of the Earth-crossing Asteroids

    NASA Astrophysics Data System (ADS)

    Pulat, Babadzhanov; Gulchekhra, Kokhirova

    2015-03-01

    The results of search for meteor showers associated with the asteroids crossing the Earthfs orbit and moving on comet-like orbits are given. It was shown that among 2872 asteroids discovered till 1.01.2005 and belonging to the Apollo and Amor groups, 130 asteroids have associated meteor showers and, therefore, are the extinct cometary nuclei.

  4. Comets and meteors in the beliefs of ancient mayas

    NASA Astrophysics Data System (ADS)

    Yershova, G. G.

    2001-12-01

    Data concerning the Mayan approach to comets and meteors have till now been available mostly from ethnographical and folklore sources which dealt, as a rule, with various beliefs and tokens. The studies of hieroglyphic texts of the Classic Period (AD 600-900) have proved that comets and meteors were undoubtedly known in this culture through astronomical observations and their periodicity.

  5. TRMM radar

    NASA Technical Reports Server (NTRS)

    Okamoto, Kenichi

    1993-01-01

    The results of a conceptual design study and the performance of key components of the Bread Board Model (BBM) of the Tropical Rainfall Measuring Mission (TRMM) radar are presented. The radar, which operates at 13.8 GHz and is designed to meet TRMM mission objectives, has a minimum measurable rain rate of 0.5 mm/h with a range resolution of 250 m, a horizontal resolution of about 4 km, and a swath width of 220 km. A 128-element active phased array system is adopted to achieve contiguous scanning within the swath. The basic characteristics of BBM were confirmed by experiments. The development of EM started with the cooperation of NASDA and CRL.

  6. Solar Radio Burst Effects and Meteor Effects: Operational Products Under Development at the Joint SMC-AFRL Rapid Prototyping Center

    NASA Astrophysics Data System (ADS)

    Quigley, S.

    2002-05-01

    The Air Force Research Laboratory (AFRL/VSB) and Detachment 11, Space & Missile Systems Center (SMC, Det 11/CIT) have combined efforts to design, develop, test, and implement graphical products for the Air Force's space weather operations center. These products are generated to analyze, specify, and forecast the effects of the near-earth space environment on Department of Defense systems and communications. Jointly-developed products that will be added to real-time operations in the near future include a solar radio background and burst effects (SoRBE) product suite, and a meteor effects (ME) product suite. The SoRBE product addresses the effect of background and event-level solar radio output on operational DoD systems. Strong bursts of radio wave emissions given off by the sun during solar ``events'' can detrimentally affect radar and satellite communication systems that have operational receiving geometries within the field of view of the sun. For some systems, even the background radiation from the sun can produce effects. The radio frequency interference (RFI) of interest occurs on VHF, UHF, and SHF frequency bands, usually lasting several minutes during a solar flare. While such effects are limited in time and area (typically a few degrees in viewing angle), they can be quite severe in magnitude. The result can be a significant lack in a radar system's ability to detect and/or track an object, and loss of a communication system's ability to receive satellite signals. The ME product will address the detrimental effects of meteors on operational DoD systems. These include impacts on satellites, visible trail observations, and radar clutter. While certain types of individual meteors can produce system effects, the initial ME product will address the more generalized range of meteor shower activity and associated affects. These effects can result in damage to satellites, incorrect assessment of satellite sensor observations, and false target returns on radar

  7. Multi-station Video Orbits of Minor Meteor Showers

    NASA Astrophysics Data System (ADS)

    Madiedo, José M.; Trigo-Rodríguez, Josep M.

    2008-06-01

    During 2006 the SPanish Meteor Network (SPMN) set up three automated video stations in Andalusia for increasing the atmospheric coverage of the already existing low-scan-rate all-sky CCD systems. Despite their initially thought complementary nature, sensitive video cameras have been employed to setup an automatic meteor detection system that provides valuable real-time information on unusual meteor activity, and remarkable fireball events. In fact, during 2006 SPMN video stations participated in the detection of two unexpected meteor outbursts: Orionids and Comae Berenicids. The three new SPMN stations guarantee almost a continuous monitoring of meteor and fireball activity in Andalusia (Spain) and also increase the chance of future meteorite recoveries. A description of the main characteristics of these new observing video stations and some examples of the trajectory, radiant and orbital data obtained so far are presented here.

  8. Meteor showers of comet C/1917 F1 Mellish

    NASA Astrophysics Data System (ADS)

    Vereš, P.; Kornoš, L.; Tóth, J.

    2011-03-01

    December Monocerotids and November Orionids are weak but established annual meteor showers active throughout November and December. Analysis of a high quality orbits subset of the SonotaCo video meteor data base shows that the distribution of orbital elements, geocentric velocity and also the orbital evolution of the meteors and potential parent body may imply a common origin for these meteors coming from the parent comet C/1917 F1 Mellish. This is also confirmed by the physical properties and activity of these shower meteors. An assumed release of meteoroids at the perihelion of the comet in the past and the sky-plane radiant distribution reveal that the December Monocerotid stream might be younger than the November Orionids. A meteoroid transversal component of ejection velocity at the perihelion must be larger than 100 m s-1. A few authors have also associated December Canis Minorids with the comet C/1917 F1 Mellish. However, we did not find any connection.

  9. First results on video meteors from Crete, Greece

    NASA Astrophysics Data System (ADS)

    Maravelias, G.

    2012-01-01

    This work presents the first systematic video meteor observations from a, forthcoming permanent, station in Crete, Greece, operating as the first official node within the International Meteor Organization's Video Network. It consists of a Watec 902 H2 Ultimate camera equipped with a Panasonic WV-LA1208 (focal length 12mm, f/0.8) lens running MetRec. The system operated for 42 nights during 2011 (August 19-December 30, 2011) recording 1905 meteors. It is significantly more performant than a previous system used by the author during the Perseids 2010 (DMK camera 21AF04.AS by The Imaging Source, CCTV lens of focal length 2.8 mm, UFO Capture v2.22), which operated for 17 nights (August 4-22, 2010) recording 32 meteors. Differences - according to the author's experience - between the two softwares (MetRec, UFO Capture) are discussed along with a small guide to video meteor hardware.

  10. To See the Unseen: A History of Planetary Radar Astronomy

    NASA Technical Reports Server (NTRS)

    Butrica, Andrew J.

    1996-01-01

    This book relates the history of planetary radar astronomy from its origins in radar to the present day and secondarily to bring to light that history as a case of 'Big Equipment but not Big Science'. Chapter One sketches the emergence of radar astronomy as an ongoing scientific activity at Jodrell Bank, where radar research revealed that meteors were part of the solar system. The chief Big Science driving early radar astronomy experiments was ionospheric research. Chapter Two links the Cold War and the Space Race to the first radar experiments attempted on planetary targets, while recounting the initial achievements of planetary radar, namely, the refinement of the astronomical unit and the rotational rate and direction of Venus. Chapter Three discusses early attempts to organize radar astronomy and the efforts at MIT's Lincoln Laboratory, in conjunction with Harvard radio astronomers, to acquire antenna time unfettered by military priorities. Here, the chief Big Science influencing the development of planetary radar astronomy was radio astronomy. Chapter Four spotlights the evolution of planetary radar astronomy at the Jet Propulsion Laboratory, a NASA facility, at Cornell University's Arecibo Observatory, and at Jodrell Bank. A congeries of funding from the military, the National Science Foundation, and finally NASA marked that evolution, which culminated in planetary radar astronomy finding a single Big Science patron, NASA. Chapter Five analyzes planetary radar astronomy as a science using the theoretical framework provided by philosopher of science Thomas Kuhn. Chapter Six explores the shift in planetary radar astronomy beginning in the 1970s that resulted from its financial and institutional relationship with NASA Big Science. Chapter Seven addresses the Magellan mission and its relation to the evolution of planetary radar astronomy from a ground-based to a space-based activity. Chapters Eight and Nine discuss the research carried out at ground

  11. Meteoric ion layers in the ionospheres of venus and mars: Early observations and consideration of the role of meteor showers

    NASA Astrophysics Data System (ADS)

    Withers, Paul; Christou, A. A.; Vaubaillon, J.

    2013-10-01

    Layers of metal ions produced by meteoroid ablation have been known in Earth's ionosphere for decades, but have only recently been discovered at Venus and Mars. Here we report the results of a search for meteoric layers in earlier datasets from Venus and Mars. We find 13 candidates at Venus in Mariner 10, Venera 9/10, and Pioneer Venus Orbiter data that augment the 18 previously identified in Venus Express data. We find 8 candidates at Mars in Mariner 7 and Mariner 9 data that augment the 71 and 10 previously identified in Mars Global Surveyor and Mars Express data, respectively. These new findings extend the ranges of conditions under which meteoric layers have been observed, support studies of the temporal variability of meteoric layers, and (for Venus) independently confirm the existence of meteoric layers. One of the proposed causes of temporal variations in the occurrence rate of meteoric layers is meteor showers. This possibility is controversial, since meteor showers have minimal observed effect on meteoric layers in Earth's ionosphere. In order to aid progress towards a resolution of this issue, we present a series of tests for this hypothesis.

  12. Bangs and Meteors from the Quiet Comet 15P/Finlay

    NASA Astrophysics Data System (ADS)

    Ye, Quan-Zhi; Brown, Peter G.; Bell, Charles; Gao, Xing; Mašek, Martin; Hui, Man-To

    2015-11-01

    Jupiter-family comet 15P/Finlay has been reportedly quiet in activity for over a century but has harbored two outbursts during its 2014/2015 perihelion passage. Here we present an analysis of these two outbursts using a set of cometary observations. The outbursts took place between 2014 December 15.4–16.0 UT and 2015 January 15.5–16.0 UT as constrained by ground-based and spacecraft observations. We find a characteristic ejection speed of V0 = 300–650 m s‑1 for the ejecta of the first outburst and V0 = 550–750 m s‑1 for that of the second outburst using a Monte Carlo dust model. The mass of the ejecta is calculated to be Md = (2–3) × 105 kg for the first outburst and Md = (4–5) × 105 kg for the second outburst, which corresponds to less than 10‑7 of the nucleus mass. The specific energy of the two outbursts is found to be (0.3–2) × 105 J kg‑1. We also revisit the long-standing puzzle of the nondetection of the hypothetical Finlayid meteor shower by performing a cued search using the 13 yr data from the Canadian Meteor Orbit Radar, which does not reveal any positives. Earth will pass the 2014/2015 outburst ejecta between 2021 October 6 at 22 hr UT and October 7 at 1 hr UT, with a chance for some significant meteor activity in the radio range, which may provide further clues to the Finlayid puzzle. A southerly radiant in the constellation of Ara will favor the observers in the southern tip of Africa.

  13. On Meteoric Dust Particles in the Near-Earth Space Environment

    NASA Astrophysics Data System (ADS)

    Mahmoudian, Alireza; Farahani, Majid Mazraeh Ei; Mohebalhojeh, Ali R.; Scales, Wayne

    2016-07-01

    Over 40 metric tons of meteoric dust enters the earth's atmosphere every day. This dust settles and creates natural dust layers in the altitude ranges between 80 and 100 kilometers which spans the earth's upper mesosphere to lower thermosphere. The dust layers in the lower atmosphere have a great impact on climate, human health as well as communication and navigation signals. The main goal of this study is the role of meteoric smoke particles on the formation of Polar Mesospheric Clouds (PMC). Recent rocket experiments have detected the presence of these particles. Since these dust layers are immersed in the earth's upper atmosphere, they become charged due to collection of electrons and ions from the earth's ionospheric plasma. Noctilucent Clouds NLCs are a fascinating visual manifestation of these dust layers. So-called Polar Mesospheric Summer Echoes PMSEs are radar echoes that are a direct consequence of the sub-visible charged dust that exists at altitudes above NLC regions. Polar Mesospheric Summer Echoes (PMSE) are strong echoes that have been typically observed in the frequency range from 50MHz to 1.3GHz and in the altitude about 85km. Unlike PMSE, Polar mesospheric winter echoes (PMWE) are less known. PMWE appear at a lower altitude and is weaker in comparison with PMSE. The focus of this study is on meteoric smoke particles and how they affect PMWE source region. Parameters associated with smoke dust particles such as size distribution, charging characteristics, density and positive or negative charge will be considered. The second part of this presentation will be on the effect of gravity waves on PMC. Full coupling to a turbulent neutral field with a statistical analysis will be discussed. Impact of a neutral turbulence driving field on small amplitude plasma fluctuations in such a configuration and some of the important consequences will be also presented. This has important consequences for electric field and potential measurements on rocket probes as

  14. A study of meteor spectroscopy and physics from earth-orbit: A preliminary survey into ultraviolet meteor spectra

    NASA Technical Reports Server (NTRS)

    Meisel, D. D.

    1976-01-01

    Preliminary data required to extrapolate available meteor physics information (obtained in the photographic, visual and near ultraviolet spectral regions) into the middle and far ultraviolet are presented. Wavelength tables, telluric attenuation factors, meteor rates, and telluric airglow data are summarized in the context of near-earth observation vehicle parameters using moderate to low spectral resolution instrumentation. Considerable attenuation is given to the problem of meteor excitation temperatures since these are required to predict the strength of UV features. Relative line intensities are computed for an assumed chondritic composition. Features of greatest predicted intensities, the major problems in meteor physics, detectability of UV meteor events, complications of spacecraft motion, and UV instrumentation options are summarized.

  15. A statistical study of meteoroid fragmentation and differential ablation using the Resolute Bay Incoherent Scatter Radar

    NASA Astrophysics Data System (ADS)

    Malhotra, Akshay; Mathews, John D.

    2011-04-01

    There has been much interest in the meteor physics community recently regarding the detailed processes by which the meteoroid mass flux arrives in the upper atmosphere. Of particular interest are the relative roles of simple ablation, differential ablation, and fragmentation in interpretation of the meteor events observed by the high-power large-aperture (HPLA) radars. An understanding of the relative roles of these mechanisms is necessary to determine whether the considerable meteor mass flux arriving in the upper atmosphere arrives mostly in nanometer dust/smoke (via fragmentation) or atomic form (via ablation), which in turn has important consequences in understanding not only the aeronomy of the region but also the formation and evolution of various upper atmospheric phenomenon such as Polar Mesospheric Summer Echoes. Using meteor observations from the newly operational Resolute Bay Incoherent Scatter Radar (RISR), we present the first statistical study showing the relative contribution of these mechanisms. We find that RISR head echoes exhibited ˜48% fragmentation, ˜32% simple ablation, and ˜20% differential ablation. We also report existence of compound meteor events exhibiting signatures of more than one mass loss mechanism. These results emphasize that the processes by which the meteoroid mass is deposited into the upper atmosphere are complex and involve all three mechanisms described here. This conclusion is unlike the previously reported results that stress the importance of one or the other of these mechanisms. These results will also contribute in improving current meteoroid disintegration/ablation models.

  16. Doppler micro sense and avoid radar

    NASA Astrophysics Data System (ADS)

    Gorwara, Ashok; Molchanov, Pavlo; Asmolova, Olga

    2015-10-01

    There is a need for small Sense and Avoid (SAA) systems for small and micro Unmanned Aerial Systems (UAS) to avoid collisions with obstacles and other aircraft. The proposed SAA systems will give drones the ability to "see" close up and give them the agility to maneuver through tight areas. Doppler radar is proposed for use in this sense and avoid system because in contrast to optical or infrared (IR) systems Doppler can work in more harsh conditions such as at dusk, and in rain and snow. And in contrast to ultrasound based systems, Doppler can better sense small sized obstacles such as wires and it can provide a sensing range from a few inches to several miles. An SAA systems comprised of Doppler radar modules and an array of directional antennas that are distributed around the perimeter of the drone can cover the entire sky. These modules are designed so that they can provide the direction to the obstacle and simultaneously generate an alarm signal if the obstacle enters within the SAA system's adjustable "Protection Border". The alarm signal alerts the drone's autopilot to automatically initiate an avoidance maneuver. A series of Doppler radar modules with different ranges, angles of view and transmitting power have been designed for drones of different sizes and applications. The proposed Doppler radar micro SAA system has simple circuitry, works from a 5 volt source and has low power consumption. It is light weight, inexpensive and it can be used for a variety of small unmanned aircraft.

  17. Compact, Automated, Frequency-Agile Microspectrofluorimeter

    NASA Technical Reports Server (NTRS)

    Fernandez, Salvador M.; Guignon, Ernest F.

    1995-01-01

    Compact, reliable, rugged, automated cell-culture and frequency-agile microspectrofluorimetric apparatus developed to perform experiments involving photometric imaging observations of single live cells. In original application, apparatus operates mostly unattended aboard spacecraft; potential terrestrial applications include automated or semiautomated diagnosis of pathological tissues in clinical laboratories, biomedical instrumentation, monitoring of biological process streams, and portable instrumentation for testing biological conditions in various environments. Offers obvious advantages over present laboratory instrumentation.

  18. Comet Machholz and the Quadrantid meteor stream

    NASA Astrophysics Data System (ADS)

    Jones, J.; Jones, W.

    1993-04-01

    Until quite recently, the Quadrantid meteor stream was considered to be an 'orphan'. Because of the difficulty in accounting for the large difference in the longitudes of the ascending nodes, McIntosh (1990) suggested that Comet Machholz and the stream have a sibling rather than a parent-child relationship. Gonczi et al. (1992) proposed that gravitational perturbations by Jupiter may be amplified sufficiently by the 2:1 resonance of the stream with Jupiter to explain the difference in the longitudes of ascending nodes if the stream was born when the comet's perihelion distance was last at its minimum about 4000 yr ago. In this paper, we show by computer simulations that, if the comet was captured at its last close approach with Jupiter about 2200 yr ago, there has been sufficient time for the resulting stream to produce most of the features of the presently observed Quadrantid/Arietid/Southern Delta-Aquarid complex.

  19. Asteroids in the Eccentrids meteor system

    NASA Astrophysics Data System (ADS)

    Terentjeva, A. K.; Barabanov, S. I.

    2016-09-01

    Among 11 673 of near-Earth objects (NEOs), 52 asteroids are identified, which, together with the Eccentrids meteor system, comprise a single population of small bodies of the Solar System with the smallest orbits of high eccentricity. Some features of this unique system of bodies are discussed in this paper. The distribution of perihelion longitudes is studied for the given group of asteroids and compared to that of the Aten asteroids, which are the most similar to the Eccentrids. The dependence is obtained of the character of perihelion longitude distribution on the eccentricities of the NEO orbits. Eight asteroid stream of the Eccentrids are found. The Eccentrids asteroids approaching the Earth's orbit along its whole length in their aphelia can pose a certain hazard for the Earth.

  20. Crowdsourcing, the great meteor storm of 1833, and the founding of meteor science.

    PubMed

    Littmann, Mark; Suomela, Todd

    2014-06-01

    Yale science professor Denison Olmsted used crowdsourcing to gather observations from across the United States of the unexpected deluge of meteors on 13 November 1833--more than 72,000/h. He used these observations (and newspaper accounts and correspondence from scientists) to make a commendably accurate interpretation of the meteor storm, overturning 2100 years of erroneous teachings about shooting stars and establishing meteor science as a new branch of astronomy. Olmsted's success was substantially based on his use of newspapers and their practice of news pooling to solicit observations from throughout the country by lay and expert observers professionally unaffiliated with Yale College and him. In today's parlance, Olmsted was a remarkably successful early practitioner of scientific crowdsourcing, also known as citizen science. He may have been the first to use mass media for crowdsourcing in science. He pioneered many of the citizen-science crowdsourcing practices that are still in use today: an open call for citizen participation, a clearly defined task, a large geographical distribution for gathering data and a rapid response to opportunistic events. Olmsted's achievement is not just that he used crowdsourcing in 1833 but that crowdsourcing helped him to advance science significantly. PMID:24917173

  1. Meteoric Metal Layer in Mars' Atmosphere: Steady-state Flux and Meteor Showers

    NASA Astrophysics Data System (ADS)

    Crismani, Matteo; Schneider, Nicholas; Jain, Sonal; Plane, John; Diego Carrillo-Sanchez, Juan; Deighan, Justin; Stevens, Michael; Evans, Scott; Chaffin, Michael; Stewart, Ian; Jakosky, Bruce

    2016-04-01

    We report on a steady state metal ion layer at Mars produced by meteoric ablation in the upper atmosphere as observed by the Imaging Ultraviolet Spectrograph (IUVS) on MAVEN. The response of the Martian atmosphere to meteoroid influx constrains cometary activity, dust dynamics, ionospheric production at Mars and meteoric smoke may represent a site of nucleation for high altitude clouds. Using observations that span more than an Earth year, we find this layer is global and steady state, contrary to previous observations, but in accordance with predictions. IUVS observations cover a range of observation conditions, which allows us to determine the variability of the Mg+ layer seasonally and geographically. In December 2015, Mars encountered three predicted meteor showers, and analysis of these events will determine whether Mars' atmosphere responds to such events dramatically, as was the case with comet Siding Spring, or more similarly to Earth. Mg is also detected, but Mg/Mg+ less than predicted by factor >3, indicative of undetermined chemical processes in the Mars atmosphere.

  2. Crowdsourcing, the great meteor storm of 1833, and the founding of meteor science.

    PubMed

    Littmann, Mark; Suomela, Todd

    2014-06-01

    Yale science professor Denison Olmsted used crowdsourcing to gather observations from across the United States of the unexpected deluge of meteors on 13 November 1833--more than 72,000/h. He used these observations (and newspaper accounts and correspondence from scientists) to make a commendably accurate interpretation of the meteor storm, overturning 2100 years of erroneous teachings about shooting stars and establishing meteor science as a new branch of astronomy. Olmsted's success was substantially based on his use of newspapers and their practice of news pooling to solicit observations from throughout the country by lay and expert observers professionally unaffiliated with Yale College and him. In today's parlance, Olmsted was a remarkably successful early practitioner of scientific crowdsourcing, also known as citizen science. He may have been the first to use mass media for crowdsourcing in science. He pioneered many of the citizen-science crowdsourcing practices that are still in use today: an open call for citizen participation, a clearly defined task, a large geographical distribution for gathering data and a rapid response to opportunistic events. Olmsted's achievement is not just that he used crowdsourcing in 1833 but that crowdsourcing helped him to advance science significantly.

  3. Architecture-Centric Methods and Agile Approaches

    NASA Astrophysics Data System (ADS)

    Babar, Muhammad Ali; Abrahamsson, Pekka

    Agile software development approaches have had significant impact on industrial software development practices. Despite becoming widely popular, there is an increasing perplexity about the role and importance of a system’s software architecture in agile approaches [1, 2]. Advocates of the vital role of architecture in achieving quality goals of large-scale-software-intensive-systems are skeptics of the scalability of any development approach that does not pay sufficient attention to architectural issues. However, the proponents of agile approaches usually perceive the upfront design and evaluation of architecture as being of less value to the customers of a system. According to them, for example, re-factoring can help fix most of the problems. Many experiences show that large-scale re-factoring often results in significant defects, which are very costly to address later in the development cycle. It is considered that re-factoring is worthwhile as long as the high-level design is good enough to limit the need for large-scale re-factoring [1, 3, 4].

  4. First GRB detections with the AGILE Minicalorimeter

    NASA Astrophysics Data System (ADS)

    Marisaldi, M.; Labanti, C.; Fuschino, F.; Galli, M.; Tavani, M.; Bulgarelli, A.; Gianotti, F.; Trifoglio, M.; Argan, A.

    2008-05-01

    The Minicalorimeter (MCAL) onboard the AGILE satellite is a 1400 cm2 scintillation detector sensitive in the energy range 0.3-200 MeV. MCAL works both as a slave of the AGILE Silicon Tracker and as an autonomous detector for transient events (BURST mode). A dedicated onboard Burst Search logic scans BURST mode data in search of count rate increase. Peculiar characteristics of the detector are the high energy spectral coverage and a timing resolution of about 2 microseconds. Even if a trigger is not issued, BURST mode data are used to build a broad band energy spectrum (scientific ratemeters) organized in 11 bands for each of the two MCAL detection planes, with a time resolution of 1 second. After the first engineering commissioning phase, following the AGILE launch on 23rd April 2007, between 22nd June and 5th November 2007 eighteen GRBs were detected offline in the scientific ratemeters data, with a detection rate of about one per week. In this paper the capabilities of the detector will be described and an overview of the first detected GRBs will be given.

  5. First GRB detections with the AGILE Minicalorimeter

    SciTech Connect

    Marisaldi, M.; Labanti, C.; Fuschino, F.; Bulgarelli, A.; Gianotti, F.; Trifoglio, M.; Galli, M.; Tavani, M.; Argan, A.

    2008-05-22

    The Minicalorimeter (MCAL) onboard the AGILE satellite is a 1400 cm{sup 2} scintillation detector sensitive in the energy range 0.3-200 MeV. MCAL works both as a slave of the AGILE Silicon Tracker and as an autonomous detector for transient events (BURST mode). A dedicated onboard Burst Search logic scans BURST mode data in search of count rate increase. Peculiar characteristics of the detector are the high energy spectral coverage and a timing resolution of about 2 microseconds. Even if a trigger is not issued, BURST mode data are used to build a broad band energy spectrum (scientific ratemeters) organized in 11 bands for each of the two MCAL detection planes, with a time resolution of 1 second. After the first engineering commissioning phase, following the AGILE launch on 23rd April 2007, between 22nd June and 5th November 2007 eighteen GRBs were detected offline in the scientific ratemeters data, with a detection rate of about one per week. In this paper the capabilities of the detector will be described and an overview of the first detected GRBs will be given.

  6. Agile manufacturing: The factory of the future

    NASA Technical Reports Server (NTRS)

    Loibl, Joseph M.; Bossieux, Terry A.

    1994-01-01

    The factory of the future will require an operating methodology which effectively utilizes all of the elements of product design, manufacturing and delivery. The process must respond rapidly to changes in product demand, product mix, design changes or changes in the raw materials. To achieve agility in a manufacturing operation, the design and development of the manufacturing processes must focus on customer satisfaction. Achieving greatest results requires that the manufacturing process be considered from product concept through sales. This provides the best opportunity to build a quality product for the customer at a reasonable rate. The primary elements of a manufacturing system include people, equipment, materials, methods and the environment. The most significant and most agile element in any process is the human resource. Only with a highly trained, knowledgeable work force can the proper methods be applied to efficiently process materials with machinery which is predictable, reliable and flexible. This paper discusses the affect of each element on the development of agile manufacturing systems.

  7. eMeteorNews: website and PDF journal

    NASA Astrophysics Data System (ADS)

    Roggemans, P.; Kacerek, R.; Koukal, J.; Miskotte, K.; Piffl, R.

    2016-01-01

    Amateur meteor workers have always been interested to exchange information and experience. In the past this was only possible via personal contacts by letter or by specialized journals. With internet a much faster medium became available and plenty of websites, mailing lists, Facebook groups, etc., have been created in order to communicate about meteors. Today there is a wealth of meteor data circulating on internet, but the information is very scattered and not directly available to everyone. The authors have been considering how to organize an easy access to the many different meteor related publications. The best solution for the current needs of amateur meteor observers proved to be a dedicated website combined with a PDF journal, both being free available without any subscription fee or registration requirement. The authors decided to start with this project and in March 2016 the website meteornews.org has been created. A first issue of eMeteorNews was prepared in April 2016. The year 2016 will be a test period for this project. The mission statement of this project is: "Minimizing overhead and editorial constraints to assure a swift exchange of information dedicated to all fields of active amateur meteor work."

  8. A meteor head echo analysis algorithm for the lower VHF band

    NASA Astrophysics Data System (ADS)

    Kero, J.; Szasz, C.; Nakamura, T.; Terasawa, T.; Miyamoto, H.; Nishimura, K.

    2012-04-01

    We have developed an automated analysis scheme for meteor head echo observations by the 46.5 MHz Middle and Upper atmosphere (MU) radar near Shigaraki, Japan (34.85° N, 136.10° E). The analysis procedure computes meteoroid range, velocity and deceleration as functions of time with unprecedented accuracy and precision. This is crucial for estimations of meteoroid mass and orbital parameters as well as investigations of the meteoroid-atmosphere interaction processes. In this paper we present this analysis procedure in detail. The algorithms use a combination of single-pulse-Doppler, time-of-flight and pulse-to-pulse phase correlation measurements to determine the radial velocity to within a few tens of metres per second with 3.12 ms time resolution. Equivalently, the precision improvement is at least a factor of 20 compared to previous single-pulse measurements. Such a precision reveals that the deceleration increases significantly during the intense part of a meteoroid's ablation process in the atmosphere. From each received pulse, the target range is determined to within a few tens of meters, or the order of a few hundredths of the 900 m long range gates. This is achieved by transmitting a 13-bit Barker code oversampled by a factor of two at reception and using a novel range interpolation technique. The meteoroid velocity vector is determined from the estimated radial velocity by carefully taking the location of the meteor target and the angle from its trajectory to the radar beam into account. The latter is determined from target range and bore axis offset. We have identified and solved the signal processing issue giving rise to the peculiar signature in signal to noise ratio plots reported by Galindo et al. (2011), and show how to use the range interpolation technique to differentiate the effect of signal processing from physical processes.

  9. Future Research in Agile Systems Development: Applying Open Innovation Principles Within the Agile Organisation

    NASA Astrophysics Data System (ADS)

    Conboy, Kieran; Morgan, Lorraine

    A particular strength of agile approaches is that they move away from ‘introverted' development and intimately involve the customer in all areas of development, supposedly leading to the development of a more innovative and hence more valuable information system. However, we argue that a single customer representative is too narrow a focus to adopt and that involvement of stakeholders beyond the software development itself is still often quite weak and in some cases non-existent. In response, we argue that current thinking regarding innovation in agile development needs to be extended to include multiple stakeholders outside the business unit. This paper explores the intra-organisational applicability and implications of open innovation in agile systems development. Additionally, it argues for a different perspective of project management that includes collaboration and knowledge-sharing with other business units, customers, partners, and other relevant stakeholders pertinent to the business success of an organisation, thus embracing open innovation principles.

  10. Data processing of solar EUV instruments on the METEOR satellite

    NASA Technical Reports Server (NTRS)

    Brown, Hipook

    1995-01-01

    The Multiple Experiment Transporter into Earth Orbit and Return-Solar EUV Experiment (METEOR-SEE) project will take daily extreme ultraviolet (EUV) irradiance spectra starting in the summer of 1995. The METEOR-SEE package consists of an EUV grating spectrograph (EGS) and a cluster of 5 soft x-ray photometers (XP's). Both these instruments have flown previously on NASA sounding rockets. Because of the scope of the project, new data processing algorithms had to be developed for the SEE instruments onboard the METEOR satellite. An overview of the data flow describes how satellite data are collected and processed. Detailed descriptions of specific routines will show what data processing entails.

  11. [Pathogenetic basis and therapeutic management of meteorism (author's transl)].

    PubMed

    Hafter, E

    1980-09-01

    Meteorism might be a symptom of organic intestinal obstruction, which needs surgical treatment in most cases. However it is often a functional phenomenon. It may be produced by aerophagy, followed by sonor, non fetid flatulence. Large amounts of gas are produced by the contact of gastric acidity with alcaline pancreatic secretion and by enzymatic digestion of food. Most of these gases are absorbed by the intestine and exhaled. In the colon bacterial fermentation and putrefaction produce fetid gas which is expulsed as flatus. Overeating, bacterial invasion of the small intestin, inflammatory and circulatory disturbances of the small bowel and obstipation favour meteorism. The treatment depends of the origin of meteorism.

  12. Double station observation of faint meteors in Nikolaev

    NASA Astrophysics Data System (ADS)

    Kulichenko, Mykola; Shulga, Alexandr; Sybiryakova, Yevgeniya

    2016-07-01

    Meteor research using TV CCD unintensified techniques was started in 2011 in Nikolaev astronomical observatory (RI NAO). The method of meteor registration is based on combined observation method developed at RI NAO. The main accent of the research is made on precise astrometry and meteoroid orbits calculation. In 2013 first double station meteors with low baseline were observed. The accuracy of visible radiant estimation is 0.7" with baseline 5 km, and less 0.5" with baseline 11.8 km. The accuracy of velocity and height estimation is 0.5 km/s and 1-2 km.

  13. Particle-based ablation model for faint meteors

    NASA Astrophysics Data System (ADS)

    Stokan, E.; Campbell-Brown, M.

    2014-07-01

    Modeling the ablation of meteoroids as they enter the atmosphere is a way of determining their physical structure and elemental composition. This can provide insight into the structure of parent bodies when combined with an orbit computed from observations. The Canadian Automated Meteor Observatory (CAMO) is a source of new, high-resolution observations of faint meteors [1]. These faint objects tend to have pre-atmospheric masses around 10^{-5} kg, corresponding to a radius of 1 mm. A wide-field camera with a 28° field of view provides guidance to a high-resolution camera that tracks meteors in flight with 1.5° field of view. Meteors are recorded with a scale of 4 m per pixel at a range of 135 km, at 110 frames per second, allowing us to investigate detailed meteor morphology. This serves as an important new constraint for ablation models, in addition to meteor brightness (lightcurves) and meteoroid deceleration. High-resolution observations of faint meteors have revealed that contemporary ablation models are not able to predict meteor morphology, even while matching the observed lightcurve and meteoroid deceleration [2]. This implies that other physical processes, in addition to fragmentation, must be considered for faint meteor ablation. We present a new, particle-based approach to modeling the ablation of small meteoroids. In this model, we simulate the collisions between atmospheric particles and the meteoroid to determine the rate of evaporation and deceleration. Subsequent collisions simulated between evaporated meteoroid particles and ambient atmospheric particles then produce light that would be observed by high-resolution cameras. Preliminary results show simultaneous agreement with meteor morphology, lightcurves, and decelerations recorded with CAMO. A sample comparison of simulated and observed meteor morphology is given in the attached figure. Several meteoroids are well-represented as solid, stony bodies, but some require modeling as a dustball [3

  14. New insights into asteroid 3200 Phaethon's meteor complex

    NASA Astrophysics Data System (ADS)

    Jakubik, Marian; Neslusan, Lubos

    2015-11-01

    In this work, we study the meteor complex originating from asteroid 3200 Phaethon. Using a modeling of variety of meteoroid streams and following their dynamical evolution, we confirm the presence of two filaments crossing the Earth observed as Geminid and Daytime Sextantid meteor showers. We use numerical integrations of modeled particles performed for several past perihelion passages of the asteroid considering (i) only the gravity of planets and (2) gravity of planets and the Poynting-Robertson effect. We present the results of comparing our models (predicted showers) with observed showers. We also point out discrepancies, their possible solutions and/or new hypothesis concerning the examined meteor complex.

  15. New approaches to some methodological problems of meteor science

    NASA Technical Reports Server (NTRS)

    Meisel, David D.

    1987-01-01

    Several low cost approaches to continuous radioscatter monitoring of the incoming meteor flux are described. Preliminary experiments were attempted using standard time frequency stations WWVH and CHU (on frequencies near 15 MHz) during nighttime hours. Around-the-clock monitoring using the international standard aeronautical beacon frequency of 75 MHz was also attempted. The techniques are simple and can be managed routinely by amateur astronomers with relatively little technical expertise. Time series analysis can now be performed using relatively inexpensive microcomputers. Several algorithmic approaches to the analysis of meteor rates are discussed. Methods of obtaining optimal filter predictions of future meteor flux are also discussed.

  16. Comet P/Machholtz and the Quadrantid meteor stream

    SciTech Connect

    Mcintosh, B.A. )

    1990-07-01

    Attention is drawn to the suggestive similarities between the calculated perturbation behavior of Comet P/Machholtz 1986 VIII, on the one hand, and on the other those of the Quadrantid, Delta Aquarid, and Arietid meteor streams. There appears to be adequate evidence for the formation by the Comets P/Machholtz and 1491-I, together with the three meteor streams, of a related complex controlled by Jupiter's gravitational perturbations; there is no comparably compelling information, however, bearing on the questions of parent-offspring or sibling relationships among these comets and meteor streams. 13 refs.

  17. Applying Agile MethodstoWeapon/Weapon-Related Software

    SciTech Connect

    Adams, D; Armendariz, M; Blackledge, M; Campbell, F; Cloninger, M; Cox, L; Davis, J; Elliott, M; Granger, K; Hans, S; Kuhn, C; Lackner, M; Loo, P; Matthews, S; Morrell, K; Owens, C; Peercy, D; Pope, G; Quirk, R; Schilling, D; Stewart, A; Tran, A; Ward, R; Williamson, M

    2007-05-02

    This white paper provides information and guidance to the Department of Energy (DOE) sites on Agile software development methods and the impact of their application on weapon/weapon-related software development. The purpose of this white paper is to provide an overview of Agile methods, examine the accepted interpretations/uses/practices of these methodologies, and discuss the applicability of Agile methods with respect to Nuclear Weapons Complex (NWC) Technical Business Practices (TBPs). It also provides recommendations on the application of Agile methods to the development of weapon/weapon-related software.

  18. Using TRMM and GPM precipitation radar for calibration of weather radars in the Philippines

    NASA Astrophysics Data System (ADS)

    Crisologo, Irene; Bookhagen, Bodo; Smith, Taylor; Heistermann, Maik

    2016-04-01

    . Koistinen, D. Michelson, M. Peura, T. Pfaff, D. B. Wolff (2015): The Emergence of Open Source Software for the Weather Radar Community, Bull. Amer. Meteor. Soc., doi: 10.1175/BAMS-D-13-00240.1

  19. NASA Meteor Cam Video of June 2, 2016 Arizona Fireball

    NASA Video Gallery

    Video obtained from the NASA meteor camera situated at the MMT Observatory on the site of the Fred Lawrence Whipple Observatory, located on Mount Hopkins, Arizona, in the Santa Rita Mountains. Cred...

  20. Activity and observability of meteor showers throughout the year

    NASA Astrophysics Data System (ADS)

    Zimnikoval, Peter

    2014-02-01

    Diagrams on the poster present the activity periods of meteor showers as well as the rising and setting times of meteor shower radiants. Plotted are sunrises, sunsets and the period of twilight. It was constructed according to data from the IMO Meteor Shower Working List. More active showers are displayed in red and less active showers in green. The diagrams are calculated for geographic latitudes of 40° N, 0° and 40° S. The time scale is given as local time at the relevant zonal meridian and supplemented by local daylight saving time. The diagrams contain rounded values of solar longitude J2000. The star chart shows the radiant positions and drift of IMO meteor showers while the other diagrams display shower activity and date of maximum.

  1. Precession of parent bodies from historical meteor outbursts

    NASA Astrophysics Data System (ADS)

    Ahn, S.-H.

    2015-01-01

    We collect records of meteor outbursts from world-wide historical archives, and analyzed them to see which meteor outbursts have existed during the last two millennia. We calculate the dates of occurrence within the sidereal year for each record, and find four prominent major meteor streams having existed continuously. The prominent and continuous meteor streams are the Lyrids, the Perseids, the Leonids, and the eta- Aquariids/Orionids pair. We also check the regression of nodal points of these streams, and find that both the Leonids and the eta-Aquariids/Orionids pair have relatively large precession rates, while the other streams have small rates. We discuss that the near-type outbursts have occurred more frequently than the far-type outbursts.

  2. Results of the IMO Video Meteor Network - December 2012

    NASA Astrophysics Data System (ADS)

    Molau, Sirko; Kac, Javor; Berko, Erno; Crivello, Stefano; Stomeo, Enrico; Igaz, Antal; Barentsen, Geert; Goncalves, Rui

    2013-04-01

    A summary of the 2012 December results of the IMO Video Meteor Network is presented, based on almost 40 000 meteors collected in over 6 800 hours of observing time. Flux density profiles of the Geminids and Ursids are presented. The Geminids peaked on December 13/14 and their activity could be followed between November 30 and December 17. No activity from meteors associated with comet 46P/Wirtanen could be detected. Shower parameters for ψ-Ursae Majorids, December α-Draconids, December κ-Draconids, Comae Berenicids, ρ-Leonids, χ-Orionids, December σ-Virginids, α-Hydrids, and December χ-Virginids are presented. The 2012 IMO Video Meteor Network observations are also summarized.

  3. The Formation and Dissipation of a Meteor Coma

    NASA Astrophysics Data System (ADS)

    Kramer, E. N.; Shestaka, I. S.

    The results of reduction of instantaneous fireball photographs are presented. The observational data testify to the fact that linear dimensions of the region radiating after the meteor's flight amount to tens and hundreds of meters, and in the case of particularly bright fireballs to some kilometers. The suggested by authors hypothesis of synchronous length change of the region of fireball afterglow alongside with its light variation is verified. The analysis of the spectral photograph obtained by authors with the method of instantaneous exposure shows that the afterglow proceeds mainly to radiation in H and K lines of CaII. Several mechanisms of ionized atoms afterglow of the meteor substance are discussed. Photometric profiles of the instantaneous images of meteors are compared with theoretical calculations made both on the supposition of the parent body fragmentation and on that of afterglow of ionized atoms of meteor substance. The conclusion on a joint effect of both above-mentioned mechanisms is obtained.

  4. A Passive FPAA-Based RF Scatter Meteor Detector

    NASA Astrophysics Data System (ADS)

    Popowicz, A.; Malcher, A.; Bernacki, K.; Fietkiewicz, K.

    2015-02-01

    In the article, we present a hardware meteor detector. The detection principle is based on the electromagnetic wave reflection from the ionized meteor trail in the atmosphere. The detector uses the ANADIGM field programmable analog array (FPAA), which is an attractive alternative for typically used detecting equipment—a PC computer with dedicated software. We implement an analog signal path using most of available FPAA resources to obtain precise audio signal detection. Our new detector was verified in collaboration with the Polish Fireball Network, the organization which monitors meteor activity in Poland. When compared with currently used signal processing PC software employing real radio meteor scatter signals, our low-cost detector proved to be more precise and reliable. Due to its cost and efficiency superiority over the current solution, the presented module is going to be implemented in the planned distributed detectors system.

  5. Martian Atmospheric Methane Plumes from Meteor Shower Infall: A Hypothesis

    NASA Astrophysics Data System (ADS)

    Fries, M.; Christou, A.; Archer, D.; Conrad, P.; Cooke, W.; Eigenbrode, J.; ten Kate, I. L.; Matney, M.; Niles, P.; Sykes, M.; Steele, A.; Treiman, A.

    2016-09-01

    Methane plumes in the martian atmosphere were previously reported, but their source remains a mystery. We hypothesize a meteor shower source, as we find a correlation between Mars/cometary orbit encounters and detections of plumes.

  6. Improving Photometric Calibration of Meteor Video Camera Systems

    NASA Technical Reports Server (NTRS)

    Ehlert, Steven; Kingery, Aaron; Cooke, William

    2016-01-01

    Current optical observations of meteors are commonly limited by systematic uncertainties in photometric calibration at the level of approximately 0.5 mag or higher. Future improvements to meteor ablation models, luminous efficiency models, or emission spectra will hinge on new camera systems and techniques that significantly reduce calibration uncertainties and can reliably perform absolute photometric measurements of meteors. In this talk we discuss the algorithms and tests that NASA's Meteoroid Environment Office (MEO) has developed to better calibrate photometric measurements for the existing All-Sky and Wide-Field video camera networks as well as for a newly deployed four-camera system for measuring meteor colors in Johnson-Cousins BV RI filters. In particular we will emphasize how the MEO has been able to address two long-standing concerns with the traditional procedure, discussed in more detail below.

  7. Meteor Outbursts and Storms from the Spacecraft Hazard Perspective

    NASA Technical Reports Server (NTRS)

    Cooke, William; Moser, Danielle; Suggs, Rob

    2004-01-01

    The recent Leonid meteor storms have propelled meteor shower forecasting from an idea into the realm of practical application, invoked several times per year by numerous spacecraft. This paper will describe shower activity predictions, which give zenith hourly rate (ZHR) as a function of time, and how these are translated into spacecraft risks. Common spacecraft meteor shower mitigation strategies will also be discussed, and the important issue as to when to implement such operations considered. It should be noted that, while the recent meteor storms did not result in the loss of a vehicle, there were a few spacecraft anomalies attributed to Leonid strikes, and the nature of these will be commented upon. Finally, we assess the current state of the art in shower forecasting, and take a look "down the road" at some possible outbursts in the near future.

  8. Radar and Lidar Radar DEM

    NASA Technical Reports Server (NTRS)

    Liskovich, Diana; Simard, Marc

    2011-01-01

    Using radar and lidar data, the aim is to improve 3D rendering of terrain, including digital elevation models (DEM) and estimates of vegetation height and biomass in a variety of forest types and terrains. The 3D mapping of vegetation structure and the analysis are useful to determine the role of forest in climate change (carbon cycle), in providing habitat and as a provider of socio-economic services. This in turn will lead to potential for development of more effective land-use management. The first part of the project was to characterize the Shuttle Radar Topography Mission DEM error with respect to ICESat/GLAS point estimates of elevation. We investigated potential trends with latitude, canopy height, signal to noise ratio (SNR), number of LiDAR waveform peaks, and maximum peak width. Scatter plots were produced for each variable and were fitted with 1st and 2nd degree polynomials. Higher order trends were visually inspected through filtering with a mean and median filter. We also assessed trends in the DEM error variance. Finally, a map showing how DEM error was geographically distributed globally was created.

  9. The investigation of multiplet structures in meteor spectra

    NASA Astrophysics Data System (ADS)

    Mozgova, Alona; Churyumov, Klim

    2016-07-01

    The structures of the iron multiplets and some other elements observed in spectra of meteor comas were considered. The catalog of iron multiplets lines was made. For each term there are indicated energy levels and wavelengths of spectral lines. For clearly explaining the transitions that accompany the radiation in given multiplets the complete Grotrian diagrams were constructed. Spectral analysis has an important role in understanding the physical processes which occur in meteor comas. Each meteor spectrum contains a large number of spectral lines belonging to atoms of different chemical elements and has a multiplet structures. The multiplets are usually spaced pairs or triples of lines but the multiplet may consist of one or more lines than three. The studying of multiplet structures in meteor spectra makes it possible to investigate the properties and a behavior of atoms of the meteor body matter. It can be used for creating models of physical and chemical processes which occur during the meteor flight in the Earth's atmosphere. For some tasks of meteor physics it needs to know not only the wavelength of a line and its belonging to some multiplet, but also both the excitation potentials of the upper and lower levels. This is useful, for example, for the study of the atoms distribution over the levels and how it differs from the Boltzmann distribution, as well as for the construction of curves growth and for determining the temperature excitation in the meteor coma, etc. For this purpose, the Walt Grotrian diagrams or chart of terms are built. They show the allowed transitions between the energy levels of the atoms. These diagrams can be used for one or more electrons (multielectrons) in the atom. The specific selection rules are taken into account in their construction. These rules are related to the change in angular momentum of the electron.

  10. ESA/ESTEC Meteor Research Group - behind the scenes

    NASA Astrophysics Data System (ADS)

    Rudawska, R.

    2016-01-01

    The ESA/ESTEC Meteor Research Group consists of a team people with one goal: understand the effects of meteoric phenomena on planetary atmospheres and surfaces, as well as on spacecraft. The team carries out observational and theoretical studies in order to increase our knowledge of the small particle complex in the solar system. This talk addresses a number of tasks within the group seen from a perspective of a research fellow.

  11. Meteor Beliefs Project: Spears of GodSpears of God

    NASA Astrophysics Data System (ADS)

    Hendrix, Howard V.; McBeath, Alastair; Gheorghe, Andrei Dorian

    2012-04-01

    A selection of genuine or supposedly sky-fallen objects from real-world sources, a mixture of weapons, tools and "magical" objects of heavenly provenance, are drawn from their re-use in the near-future science-fiction novel Spears of God by author Howard V Hendrix, with additional discussion. The book includes other meteoric and meteoritic items too, some of which have been the subject of previous Meteor Beliefs Project examinations.

  12. Comet Encke: Meteor metallic ion identification by mass spectrometer

    NASA Technical Reports Server (NTRS)

    Goldberg, R. A.; Aikin, A. C.

    1973-01-01

    Positive metallic ions have been measured in the earth's atmosphere between 85 and 120 km, during the period of the beta Taurids meteor shower, which is associated with Comet Encke. The ions originate during and following ablation of extraterrestrial debris by the earth's atmosphere. The enhancement of metal ion density during meteor showers is primary evidence for their extraterrestrial origin. The present results were obtained from a rocket-borne ion mass spectrometer.

  13. Results of the IMO Video Meteor Network - November 2012

    NASA Astrophysics Data System (ADS)

    Molau, Sirko; Kac, Javor; Berko, Erno; Crivello, Stefano; Stomeo, Enrico; Igaz, Antal; Barentsen, Geert; Goncalves, Rui

    2013-02-01

    More than 27 000 meteors were registered by the IMO Video Meteor Network cameras in 2012 November. Flux density profiles are presented for the Leonids, Northern and Southern Taurids and compared to profiles from 2011. It is confirmed that the Southern October delta-Arietids are an early segment of the Southern Taurids. Shower parameters for November iota-Draconids, November Orionids, December Monocerotids and sigma-Hydrids are presented.

  14. On the accuracy of orbits from video meteor observations

    NASA Astrophysics Data System (ADS)

    Skokić, I.; Šegon, D.; Kurtović, G.

    2016-01-01

    The velocity limits of the meteor shower's geocentric velocity distribution from the CAMS meteoroid database were determined and used to calculate perturbed orbits. These were compared with the mean stream orbit using the DSH dissimilarity criterion. It was found that for the slow meteor showers (Alpha Capricornids and Geminids), the resulting orbits are within the generally accepted cutoff values for stream associations, while for the faster showers (Perseids, Orionids and Quadrantids) the resulting orbits differ significantly from their mean stream orbit.

  15. Results of the IMO Video Meteor Network - September 2010

    NASA Astrophysics Data System (ADS)

    Molau, Sirko; Kac, Javor

    2010-12-01

    In September 2010, 46 cameras of the IMO Video Meteor Network were active with more than 3 700 hours of observations and almost 19 000 meteors recorded. Minor showers active in September were explored. Activity profiles of the September epsilon-Perseids, nu-Eridanids and iota-Cassiopeiids are presented. Signs of early activity of the Orionids were searched for. A small increase could be detected from September 25, and convincing rates could be observed from September 30.

  16. Influence of meteor showers on Earth's upper atmosphere temperature

    NASA Astrophysics Data System (ADS)

    Salivonov, A.; Kozak, L.

    2005-04-01

    The warming of night atmosphere of the Earth during action of meteor showers is analyzed. It was used a satellite measurements in Earth's upper atmosphere for the period of 1993 in height range 85-130 km. Temperature values were obtained with the help of device WINDII (Wind Imaging Interferometer) installed on the America-French satellite UARS (Upper Atmosphere Research Satellite). The most intensive meteor showers Perseids, Leonids, Orionids and Geminids were considered.

  17. Results of the IMO Video Meteor Network - November 2010

    NASA Astrophysics Data System (ADS)

    Molau, Sirko; Kac, Javor; Berko, Erno; Crivello, Stefano; Stomeo, Enrico; Igaz, Antal

    2011-02-01

    Preliminary results of the IMO Video Meteor Network data, collected by 50 cameras of the network, are presented. Almost 16 000 meteors were recorded in more than 3 300 hours of observing time. The activity profile of the Leonids is presented, with their maximum occurring on November 18. Activity profiles of two November minor showers, the Andromedids and the November Orionids, are also presented, fitting well to results from previous years.

  18. Results of the IMO Video Meteor Network - October 2015

    NASA Astrophysics Data System (ADS)

    Molau, S.; Crivello, S.; Goncalves, R.; Saraiva, C.; Stomeo, E.; Kac, J.

    2016-02-01

    The October 2015 overview of IMO Video Meteor Network observations is presented, covering more than 9 600 hours of observations with almost 55 000 recorded meteors. The flux density profile is presented for the October Ursae Majorids for the years 2011 to 2015. The flux density profiles for Orionids are presented for years 2012 to 2015, showing a broad maximum between October 20 and 27.

  19. Results of the IMO Video Meteor Network - January 2016

    NASA Astrophysics Data System (ADS)

    Molau, S.; Crivello, S.; Goncalves, R.; Saraiva, C.; Stomeo, E.; Kac, J.

    2016-06-01

    The January 2016 report of IMO Video Meteor Network observations is presented, based on more than 9 000 hours of observations with almost 28 000 meteors recorded. The flux density profile is presented for the 2016 Quadrantids and compared to the profiles from the years 2011-2015. The flux density profile is also presented for the 2016 gamma-Ursae Minorids. Development of a new algorithm for the calculation of the limiting magnitude is presented.

  20. Origin of meteor swarms of the Arietid and Geminid types

    SciTech Connect

    Lebedinets, V.N.

    1985-10-01

    The author proposes a physical mechanism for the formation of meteor swarms on orbits of small size and very small perihelion distance, similar to the orbits of Arietid and Geminid meteor swarms, which are rarely encountered among the larger bodies of the solar system, and he justifies the mechanism mathematically. He shows that comets can transfer to such orbits from orbits of large size during evaporation of their ice nuclei under the action of reactive drag.

  1. Agile informatics: application of agile project management to the development of a personal health application.

    PubMed

    Chung, Jeanhee; Pankey, Evan; Norris, Ryan J

    2007-01-01

    We describe the application of the Agile method-- a short iteration cycle, user responsive, measurable software development approach-- to the project management of a modular personal health record, iHealthSpace, to be deployed to the patients and providers of a large academic primary care practice. PMID:18694014

  2. Agile informatics: application of agile project management to the development of a personal health application.

    PubMed

    Chung, Jeanhee; Pankey, Evan; Norris, Ryan J

    2007-10-11

    We describe the application of the Agile method-- a short iteration cycle, user responsive, measurable software development approach-- to the project management of a modular personal health record, iHealthSpace, to be deployed to the patients and providers of a large academic primary care practice.

  3. ``Hiss, clicks and pops'' - The enigmatic sounds of meteors

    NASA Astrophysics Data System (ADS)

    Finnegan, J. A.

    2015-04-01

    The improbability of sounds heard simultaneously with meteors allows the phenomenon to remain on the margins of scientific interest and research. This is unjustified, since these audibly perceived electric field effects indicate complex, inconsistent and still unresolved electric-magnetic coupling and charge dynamics; interacting between the meteor; the ionosphere and mesosphere; stratosphere; troposphere and the surface of the earth. This paper reviews meteor acoustic effects, presents illustrating reports and hypotheses and includes a summary of similar and additional phenomena observed during the 2013 February 15 asteroid fragment disintegration above the Russian district of Chelyabinsk. An augmenting theory involving near ground, non uniform electric field production of Ozone, as a stimulated geo-physical phenomenon to explain some hissing `meteor sounds' is suggested in section 2.2. Unlike previous theories, electric-magnetic field fluctuation rates are not required to occur in the audio frequency range for this process to acoustically emit hissing and intermittent impulsive sounds; removing the requirements of direct conversion, passive human transduction or excited, localised acoustic `emitters'. Links to the Armagh Observatory All-sky meteor cameras, electrophonic meteor research and full construction plans for an extremely low frequency (ELF) receiver are also included.

  4. Optical observations of meteors in RI Nikolaev Astronomical Observatory

    NASA Astrophysics Data System (ADS)

    Shulga, Alexander; Sybiryakova, Yevgeniya; Kulichenko, Nikolay; Vovk, Vasyl

    2015-08-01

    Video observations of meteors at the RI NAO are conducted using meteor patrol, which includes 6 optical telescopes (4 lenses: f = 85 mm, f/1.8; 2 lenses: f = 100 mm, f/2.0) equipped with a TV CCD cameras WAT-902H2 (768×576, 8.6×8.3µ). The field of view of 4 telescopes is 3.2°×4.2° and 2.7°×3.6° for 2 telescopes. System doesn't have any intensifier. Each video system is contained in a hermetic capsule to prevent it from rain and other aggressive meteorological conditions. Cameras work in the interlace mode with rate 50 half-frames per second.During 2011-2014 4135 single station meteors were observed. The mean duration of observed meteor trajectories are in 0.05-0.6 s. Double station observation campaigns has been started in September 2013 and it is still working with baseline 11.8 km. During September 2013 - September 2014 total number of observed meteor trajectories was 1757. Number of double station meteors - 328. The mean accuracy of visible radiant determination is less than 0.5 arc sec, more than 80% of radiates have standard deviation less than 0.2 arc sec.

  5. Agile Development Methods for Space Operations

    NASA Technical Reports Server (NTRS)

    Trimble, Jay; Webster, Chris

    2012-01-01

    Main stream industry software development practice has gone from a traditional waterfall process to agile iterative development that allows for fast response to customer inputs and produces higher quality software at lower cost. How can we, the space ops community, adopt state of the art software development practice, achieve greater productivity at lower cost, and maintain safe and effective space flight operations? At NASA Ames, we are developing Mission Control Technologies Software, in collaboration with Johnson Space Center (JSC) and, more recently, the Jet Propulsion Laboratory (JPL).

  6. Flight dynamics research for highly agile aircraft

    NASA Technical Reports Server (NTRS)

    Nguyen, Luat T.

    1989-01-01

    This paper highlights recent results of research conducted at the NASA Langley Research Center as part of a broad flight dynamics program aimed at developing technology that will enable future combat aircraft to achieve greatly enhanced agility capability at subsonic combat conditions. Studies of advanced control concepts encompassing both propulsive and aerodynamic approaches are reviewed. Dynamic stall phenomena and their potential impact on maneuvering performance and stability are summarized. Finally, issues of mathematical modeling of complex aerodynamics occurring during rapid, large amplitude maneuvers are discussed.

  7. SPA Meteor Section Results: November -- December 1999

    NASA Astrophysics Data System (ADS)

    McBeath, A.

    2000-10-01

    Results and reports submitted to the SPA Meteor Section for November and December, 1999, are summarized, except for the Leonid details already discussed [1-3]. The Taurids received some useful coverage in early November, without anything unusual being detected. A brilliant fireball accurred around 22h10m UT on November 28 over southeast Ireland, after which about 271 g of L6 chondritic meteorites were recovered near Leighlinbridge, County Carlow, Ireland, the first recovered meteorite fall in the British Isles since 1991. Two other bright fireballs accurred on November 27-28 and 29-30 over Europe as well. December 13-14 saw the highest Geminid ZHRs, 100 +- 10, during a well-observed Geminid epoch. Radio data showed strong echo counts on both December 13 and 14, with the latter date (lambda approx 263 deg, eq. J2000.0) producing the highest counts generally, but with no specific clear maximum time. The Ursid peak was detected by radio only, giving a very weak showing in most data sets especially around lambda = 269-270 deg.

  8. Radiant ephemeris of the Taurid meteor complex

    NASA Astrophysics Data System (ADS)

    Triglav-Čekada, M.; Arlt, R.

    2005-04-01

    The radiant ephemeris of the Taurid complex meteor showers derived from IMO video observations from 1995-2004 is presented. Detailed radiant ephemerides of the Northern (NPI) and Southern Piscids (SPI) and the Northern (NTA) and Southern Taurids (STA) are derived. Tentative radiant motions of the Northern and Southern chi-Orionids (ORN and ORS) are presented. The Taurids (NTA and STA) are active from the beginning of September to the end of November; the Southern Taurids disappear earlier around November 20. While the Northern Taurids appear to be slower until about October 20 than in the second part of their activity period, the Southern Taurids do not exhibit sub-components. The Southern Piscids (SPI) are active only in September and their activity is much lower than the activity of the Taurids at that time. The Northern Piscids are a little more prominent than the Southern Piscids and are detectable from the beginning of September to October 18, with a probable maximum period from September 20 to October 2.

  9. Remote Sensing of Ocean Currents Using a Multifrequency Microwave Radar

    NASA Astrophysics Data System (ADS)

    Popstefanija, Ivan P.

    A remote sensing system for measuring ocean surface currents is presented in this thesis. Included are a review of the Stepped Frequency Delta K (SFDK) radar system hardware, a description of the system performance, experimental results of ocean current measurements, and comparisons of the measurements with a conventional current probe and a wind driven current model. Important features of this radar system are (1) its capability to perform real time processing of the collected data and (2) its frequency agility, which provides significant improvement of the system's signal-to-clutter ratio. The real time processing capabilities were essential to the collection and monitoring of the ocean currents for long periods of time that is necessary to understand and interpret the results. The SFDK radar participated in two month long experiments. During the first experiment at N. Truro, MA, the SFDK radar demonstrated its ability to make precise phase velocity measurements over long periods of time. During the second experiment on the Chesapeake Light Tower, the radar was able to sense both tidal and wind driven current components. Comparison of radar data and in situ measurements during the CLT experiment shows that the instrument possesses a unique capability to measure near surface currents--not possible with in situ probes.

  10. Agile Methods for Open Source Safety-Critical Software

    PubMed Central

    Enquobahrie, Andinet; Ibanez, Luis; Cheng, Patrick; Yaniv, Ziv; Cleary, Kevin; Kokoori, Shylaja; Muffih, Benjamin; Heidenreich, John

    2011-01-01

    The introduction of software technology in a life-dependent environment requires the development team to execute a process that ensures a high level of software reliability and correctness. Despite their popularity, agile methods are generally assumed to be inappropriate as a process family in these environments due to their lack of emphasis on documentation, traceability, and other formal techniques. Agile methods, notably Scrum, favor empirical process control, or small constant adjustments in a tight feedback loop. This paper challenges the assumption that agile methods are inappropriate for safety-critical software development. Agile methods are flexible enough to encourage the right amount of ceremony; therefore if safety-critical systems require greater emphasis on activities like formal specification and requirements management, then an agile process will include these as necessary activities. Furthermore, agile methods focus more on continuous process management and code-level quality than classic software engineering process models. We present our experiences on the image-guided surgical toolkit (IGSTK) project as a backdrop. IGSTK is an open source software project employing agile practices since 2004. We started with the assumption that a lighter process is better, focused on evolving code, and only adding process elements as the need arose. IGSTK has been adopted by teaching hospitals and research labs, and used for clinical trials. Agile methods have matured since the academic community suggested they are not suitable for safety-critical systems almost a decade ago, we present our experiences as a case study for renewing the discussion. PMID:21799545

  11. A Roadmap for Using Agile Development in a Traditional Environment

    NASA Technical Reports Server (NTRS)

    Streiffert, Barbara A.; Starbird, Thomas; Grenander, Sven

    2006-01-01

    One of the newer classes of software engineering techniques is called 'Agile Development'. In Agile Development software engineers take small implementation steps and, in some cases they program in pairs. In addition, they develop automatic tests prior to implementing their small functional piece. Agile Development focuses on rapid turnaround, incremental planning, customer involvement and continuous integration. Agile Development is not the traditional waterfall method or even a rapid prototyping method (although this methodology is closer to Agile Development). At Jet Propulsion Laboratory (JPL) a few groups have begun Agile Development software implementations. The difficulty with this approach becomes apparent when Agile Development is used in an organization that has specific criteria and requirements handed down for how software development is to be performed. The work at the JPL is performed for the National Aeronautics and Space Agency (NASA). Both organizations have specific requirements, rules and procedure for developing software. This paper will discuss the some of the initial uses of the Agile Development methodology, the spread of this method and the current status of the successful incorporation into the current JPL development policies.

  12. A Roadmap for Using Agile Development in a Traditional Environment

    NASA Technical Reports Server (NTRS)

    Streiffert, Barbara; Starbird, Thomas; Grenander, Sven

    2006-01-01

    One of the newer classes of software engineering techniques is called 'Agile Development'. In Agile Development software engineers take small implementation steps and, in some cases, they program in pairs. In addition, they develop automatic tests prior to implementing their small functional piece. Agile Development focuses on rapid turnaround, incremental planning, customer involvement and continuous integration. Agile Development is not the traditional waterfall method or even a rapid prototyping method (although this methodology is closer to Agile Development). At the Jet Propulsion Laboratory (JPL) a few groups have begun Agile Development software implementations. The difficulty with this approach becomes apparent when Agile Development is used in an organization that has specific criteria and requirements handed down for how software development is to be performed. The work at the JPL is performed for the National Aeronautics and Space Agency (NASA). Both organizations have specific requirements, rules and processes for developing software. This paper will discuss some of the initial uses of the Agile Development methodology, the spread of this method and the current status of the successful incorporation into the current JPL development policies and processes.

  13. Agile manufacturing in Intelligence, Surveillance and Reconnaissance (ISR)

    NASA Astrophysics Data System (ADS)

    DiPadua, Mark; Dalton, George

    2016-05-01

    The objective of the Agile Manufacturing for Intelligence, Surveillance, and Reconnaissance (AMISR) effort is to research, develop, design and build a prototype multi-intelligence (multi-INT), reconfigurable pod demonstrating benefits of agile manufacturing and a modular open systems approach (MOSA) to make podded intelligence, surveillance, and reconnaissance (ISR) capability more affordable and operationally flexible.

  14. Peridigm summary report : lessons learned in development with agile components.

    SciTech Connect

    Salinger, Andrew Gerhard; Mitchell, John Anthony; Littlewood, David John; Parks, Michael L.

    2011-09-01

    This report details efforts to deploy Agile Components for rapid development of a peridynamics code, Peridigm. The goal of Agile Components is to enable the efficient development of production-quality software by providing a well-defined, unifying interface to a powerful set of component-based software. Specifically, Agile Components facilitate interoperability among packages within the Trilinos Project, including data management, time integration, uncertainty quantification, and optimization. Development of the Peridigm code served as a testbed for Agile Components and resulted in a number of recommendations for future development. Agile Components successfully enabled rapid integration of Trilinos packages into Peridigm. A cost of this approach, however, was a set of restrictions on Peridigm's architecture which impacted the ability to track history-dependent material data, dynamically modify the model discretization, and interject user-defined routines into the time integration algorithm. These restrictions resulted in modifications to the Agile Components approach, as implemented in Peridigm, and in a set of recommendations for future Agile Components development. Specific recommendations include improved handling of material states, a more flexible flow control model, and improved documentation. A demonstration mini-application, SimpleODE, was developed at the onset of this project and is offered as a potential supplement to Agile Components documentation.

  15. Agile Methods for Open Source Safety-Critical Software.

    PubMed

    Gary, Kevin; Enquobahrie, Andinet; Ibanez, Luis; Cheng, Patrick; Yaniv, Ziv; Cleary, Kevin; Kokoori, Shylaja; Muffih, Benjamin; Heidenreich, John

    2011-08-01

    The introduction of software technology in a life-dependent environment requires the development team to execute a process that ensures a high level of software reliability and correctness. Despite their popularity, agile methods are generally assumed to be inappropriate as a process family in these environments due to their lack of emphasis on documentation, traceability, and other formal techniques. Agile methods, notably Scrum, favor empirical process control, or small constant adjustments in a tight feedback loop. This paper challenges the assumption that agile methods are inappropriate for safety-critical software development. Agile methods are flexible enough to encourage the rightamount of ceremony; therefore if safety-critical systems require greater emphasis on activities like formal specification and requirements management, then an agile process will include these as necessary activities. Furthermore, agile methods focus more on continuous process management and code-level quality than classic software engineering process models. We present our experiences on the image-guided surgical toolkit (IGSTK) project as a backdrop. IGSTK is an open source software project employing agile practices since 2004. We started with the assumption that a lighter process is better, focused on evolving code, and only adding process elements as the need arose. IGSTK has been adopted by teaching hospitals and research labs, and used for clinical trials. Agile methods have matured since the academic community suggested they are not suitable for safety-critical systems almost a decade ago, we present our experiences as a case study for renewing the discussion.

  16. Agile Methods for Open Source Safety-Critical Software.

    PubMed

    Gary, Kevin; Enquobahrie, Andinet; Ibanez, Luis; Cheng, Patrick; Yaniv, Ziv; Cleary, Kevin; Kokoori, Shylaja; Muffih, Benjamin; Heidenreich, John

    2011-08-01

    The introduction of software technology in a life-dependent environment requires the development team to execute a process that ensures a high level of software reliability and correctness. Despite their popularity, agile methods are generally assumed to be inappropriate as a process family in these environments due to their lack of emphasis on documentation, traceability, and other formal techniques. Agile methods, notably Scrum, favor empirical process control, or small constant adjustments in a tight feedback loop. This paper challenges the assumption that agile methods are inappropriate for safety-critical software development. Agile methods are flexible enough to encourage the rightamount of ceremony; therefore if safety-critical systems require greater emphasis on activities like formal specification and requirements management, then an agile process will include these as necessary activities. Furthermore, agile methods focus more on continuous process management and code-level quality than classic software engineering process models. We present our experiences on the image-guided surgical toolkit (IGSTK) project as a backdrop. IGSTK is an open source software project employing agile practices since 2004. We started with the assumption that a lighter process is better, focused on evolving code, and only adding process elements as the need arose. IGSTK has been adopted by teaching hospitals and research labs, and used for clinical trials. Agile methods have matured since the academic community suggested they are not suitable for safety-critical systems almost a decade ago, we present our experiences as a case study for renewing the discussion. PMID:21799545

  17. Agile Bodies: A New Imperative in Neoliberal Governance

    ERIC Educational Resources Information Center

    Gillies, Donald

    2011-01-01

    Modern business discourse suggests that a key bulwark against market fluctuation and the threat of failure is for organizations to become "agile'", a more dynamic and proactive position than that previously afforded by mere "flexibility". The same idea is also directed at the personal level, it being argued that the "agile" individual is better…

  18. Introduction to Stand-up Meetings in Agile Methods

    NASA Astrophysics Data System (ADS)

    Hasnain, Eisha; Hall, Tracy

    2009-05-01

    In recent years, agile methods have become more popular in the software industry. Agile methods are a new approach compared to plan-driven approaches. One of the most important shifts in adopting an agile approach is the central focus given to people in the process. This is exemplified by the independence afforded to developers in the development work they do. This work investigates the opinions of practitioners about daily stand-up meetings in the agile methods and the role of developer in that. For our investigation we joined a yahoo group called "Extreme Programming". Our investigation suggests that although trust is an important factor in agile methods. But stand-ups are not the place to build trust.

  19. Combining Agile and Traditional: Customer Communication in Distributed Environment

    NASA Astrophysics Data System (ADS)

    Korkala, Mikko; Pikkarainen, Minna; Conboy, Kieran

    Distributed development is a radically increasing phenomenon in modern software development environments. At the same time, traditional and agile methodologies and combinations of those are being used in the industry. Agile approaches place a large emphasis on customer communication. However, existing knowledge on customer communication in distributed agile development seems to be lacking. In order to shed light on this topic and provide practical guidelines for companies in distributed agile environments, a qualitative case study was conducted in a large globally distributed software company. The key finding was that it might be difficult for an agile organization to get relevant information from a traditional type of customer organization, even though the customer communication was indicated to be active and utilized via multiple different communication media. Several challenges discussed in this paper referred to "information blackout" indicating the importance of an environment fostering meaningful communication. In order to evaluate if this environment can be created a set of guidelines is proposed.

  20. A Case Study of Coordination in Distributed Agile Software Development

    NASA Astrophysics Data System (ADS)

    Hole, Steinar; Moe, Nils Brede

    Global Software Development (GSD) has gained significant popularity as an emerging paradigm. Companies also show interest in applying agile approaches in distributed development to combine the advantages of both approaches. However, in their most radical forms, agile and GSD can be placed in each end of a plan-based/agile spectrum because of how work is coordinated. We describe how three GSD projects applying agile methods coordinate their work. We found that trust is needed to reduce the need of standardization and direct supervision when coordinating work in a GSD project, and that electronic chatting supports mutual adjustment. Further, co-location and modularization mitigates communication problems, enables agility in at least part of a GSD project, and renders the implementation of Scrum of Scrums possible.