3,083 research outputs found

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

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    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

    MENTOR: Adding an outlying receiver to an ST radar for meteor-wind measurement

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    Radar scattering from ionized meteor trails has been used for many years as a way to determine mesopause-level winds. Scattering occurs perpendicular to the trails, and since the ionizing efficiency of the incoming meteoroids depends on the cosine of the zenith angle of the radiant, echoes directly overhead are rare. Stratosphere-troposphere (ST) radars normally sample within 15 deg of the vertical, and thus receive few meteor echoes. Even the higher powdered mesosphere-stratosphere-troposphere (MST) radars are not good meteor radars, although they were used to successfully retrieved meteor winds from the Poker Flat, Alaska MST radar by averaging long data intervals. It has been suggested that a receiving station some distance from an ST radar could receive pulses being scattered from meteor trails, determine the particular ST beam in which the scattering occurred, measure the radial Doppler velocity, and thus determine the wind field. This concept has been named MENTOR (Meteor Echoes; No Transmitter, Only Receivers)

    Relationship of isolated turbulent regions to the general turbulent background, part 4.4A

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    The atmosphere below 100 km is often referred to as the homosphere; the region above, the heterosphere. In the homosphere, constitutents are mixed, and average molecular weight is constant. In the heterosphere, diffusive separation occurs, and species tend to fractionate; average molecular weight decreases with height. Mixing in the homosphere has its source dynamical (wind) energy. Against this background turbulence, intermittent enhancements of turbulent intensity are observed. Some of these enhancements are long lived -- for example, a turbulent layer at approximately 86 km altitude seems to be almost a permanent feature of the (global) daytime D region, as oserved by partial reflection. This may well be a delineation of the mesopause level, since long-term radio meteor studies have shown approx. 85 km to be the breakpoint between thermospheric circulation above, and mesospheric circulation below. The use of stratosphere-troposphere (ST) radars in the lower atmosphere, and mesosphere-stratosphere-troposphere (MST) and partial-reflection radars in the mesosphere for height/time profiles of turbulent intensity is discussed

    Theoretical and experimental investigations of upper atmosphere dynamics

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    A brief overview of the significant contributions made to the understanding of the dynamics of the Earth's upper atmosphere is presented, including the addition of winds and diffusion to the semi-empirical Global Reference Atmospheric Model developed for the design phase of the Space Shuttle, reviews of turbulence in the lower thermosphere, the dynamics of the equatorial mesopause, stratospheric warming effects on mesopause level dynamics, and the relevance of these studies to the proposed Middle Atmosphere Program (1982-85). A chronological bibliography, with abstracts of all papers published, is also included

    INDICATORS OF INHABITANT, HOUSEHOLD, FAMILY AND ECONOMIC GROWTH: SOUTH CAROLINA AND NORTH CAROLINA

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    Social and economic futures are dependent on numbers of housing units, families, households and individuals, and on many characteristics of aggregate populations. Research reported in this manuscript is focused on the states of North Carolina and South Carolina and the counties therein. The chief concern is change; e.g., numerical and percentage increase or decrease. These dynamics refer to basic components of population: births, deaths and residential relocation.Consumer/Household Economics,

    A high resolution scintillating fiber tracker with SiPM readout for the PEBS experiment

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    Using thin scintillating fibers with Silicon Photomultiplier (SiPM) readout a mo dular high-resolution charged-particle tracking detector has been designed. The fiber modules consist of 2 x 5 layers of 128 round multiclad scintillating fiber s of 0.250mm diameter. The fibers are read out by four SiPM arrays (8mm x 1mm) e ach on either end of the module.Comment: 6 pages, 5 figures, presented at the ICATPP 1

    Four-D global reference atmosphere technical description, part 1

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    An empirical atmospheric model was developed which generates values for pressure, density, temperature, and winds from surface levels to orbital altitudes. The output parameters consist of components for: (1) latitude, longitude, and altitude dependent monthly and annual means; (2) quasi-biennial oscillations; and (3) random perturbations to simulate partially the variability due to synoptic, diurnal, planetary wave, and gravity wave variations. Quasi-biennial and random variation perturbations are computed from parameters determined from various empirical studies and are added to the monthly mean values. This model has been developed as a computer program called PROFILE which can be used to generate altitude profiles of atmospheric parameters along any simulated trajectory through the atmosphere. The PROFILE program was developed for design applications in the space shuttle program. Other applications of the model are discussed, such as for global circulation and diffusion studies, and for generating profiles for comparison with other atmospheric measurement techniques, (e.g. satellite measured temperature profiles)

    How to use the WWW to distribute STI

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    This presentation explains how to use the World Wide Web (WWW) to distribute scientific and technical information as hypermedia. WWW clients and servers use the HyperText Transfer Protocol (HTTP) to transfer documents containing links to other text, graphics, video, and sound. The standard language for these documents is the HyperText MarkUp Language (HTML). These are simply text files with formatting codes that contain layout information and hyperlinks. HTML documents can be created with any text editor or with one of the publicly available HTML editors or convertors. HTML can also include links to available image formats. This presentation is available online. The URL is http://sti.larc.nasa. (followed by) gov/demos/workshop/introtext.html
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