Science.gov

Sample records for 0-70 km altitude

  1. Cape Canaveral, Florida range reference atmosphere 0-70 km altitude

    NASA Technical Reports Server (NTRS)

    Tingle, A. (Editor)

    1983-01-01

    The RRA contains tabulations for monthly and annual means, standard deviations, skewness coefficients for wind speed, pressure temperature, density, water vapor pressure, virtual temperature, dew-point temperature, and the means and standard deviations for the zonal and meridional wind components and the linear (product moment) correlation coefficient between the wind components. These statistical parameters are tabulated at the station elevation and at 1 km intervals from sea level to 30 km and at 2 km intervals from 30 to 90 km altitude. The wind statistics are given at approximately 10 m above the station elevations and at altitudes with respect to mean sea level thereafter. For those range sites without rocketsonde measurements, the RRAs terminate at 30 km altitude or they are extended, if required, when rocketsonde data from a nearby launch site are available. There are four sets of tables for each of the 12 monthly reference periods and the annual reference period.

  2. Range Reference Atmosphere 0-70 km Altitude, Barking Sands, Hawaii

    DTIC Science & Technology

    1983-12-01

    TABLE E. LIST OF PRIMARY PHYSICAL CONSTANTS P 0 = standard atmospheric pressure at sea level = 1.013250 x 10~ Newton ~m2 = 2116.22 lb/ft2 p0 = standard...S.D. MECAN KM P8 "a DEG K DEG K 0:0 K DCG K .000 22.139 2.701 .05 301.88 1.39 .49 292.17 2.0c -.48 329. 329. .005 22.090 2.694 .05 3c0.85 1.39 .49

  3. Neutral Wind Observations below 200 km altitudes

    NASA Astrophysics Data System (ADS)

    Watanabe, S.; Abe, T.; Habu, H.; Kakinami, Y.; Larsen, M. F.; Pfaff, R. F., Jr.; Yamamoto, M.

    2015-12-01

    Neutral Wind Observations below 200 km altitudesS. Watanabe1, T. Abe2, H. Habu2, Y. Kakinami3, M. Larsen4, R. Pfaff5, M. Yamamoto6, M-Y. Yamamoto31Hokkaido University/Hokkaido Information University, 2JAXA/ISAS, 3Kochi University of Technology, 4Clemson University, 5NASA/Goddard Space Flight Center, 6Kyoto University, Neutral wind in the thermosphere is one of the key parameters to understand the ionosphere-thermosphere coupling process. JAXA/ISAS successfully launched sounding rockets from Uchinoura Space Center (USC) on September 2, 2007, January 12, 2012, and July 20, 2013, and NASA launched sounding rockets from Kwajalein on May 7, 2013 and from Wallops on July 4, 2013. The rockets installed Lithium and/or TMA canisters as well as instruments for plasma and electric and magnetic fields. The atomic Lithium gases were released at altitudes between 150 km and 300 km in the evening on September 2, 2007, at altitude of ~100 km in the morning on January 12, 2012, at altitude of ~120km in the midnight on July 20, 2013, at altitude between 150 km and 300 km in the evening on May 7, 2013 and at altitude of ~150 km in the noon on July 4, 2013. The Lithium atoms were scattering sunlight by resonance scattering with wavelength of 670nm. However, the Lithium atoms scattered moon light on July 20, 2013. The moon light scattering is the first time to use for thermospheric wind measurement in the midnight. The Lithium clouds/trails and TMA trails showed clearly the neutral wind shears and atmospheric waves at ~150 km altitude in the lower thermosphere for all local time.

  4. Range Reference Atmosphere 0-70 KM Altitude, Point Mugu California

    DTIC Science & Technology

    1983-09-01

    equation of state , and the probability principles that are related through these physical equations. The document shall serve as an authoritative...34 b. Consider augmenting data base from Ely or Salt Lake City. viii "°. . . . . . .. . . . . All final computations were performed by the United States ...appropriate corporate division, school, laboratory, etc., of the author. List city, state , and ZIP Code. Block 10 Program Element, Project, Task Area

  5. Range Reference Atmosphere, 0-70 km Altitude, Vandenberg AFB, California,

    DTIC Science & Technology

    1983-04-01

    000oc009\\,M 0j 0M-t 33 0O3o007n *fl3 C= CC, C,0 0 LO o Nr -P nQ - 77 0 ! . 20, 0 .7 m rr - ’ny3y 13ru( HD 1 r r F0f m 0. M 9 a -13rt 3 ’ 73 M 0 0’ 0 7...3 . . . . . . . . . . . . . 0~ -2 s mNf I s N -11-WI- c~~~(-l C) -, nr 0 a 000 U o C. m, C, 11Q 0 ID t L* T fu I~ In 0 In a u -t r, a)0 I, W" 0 ID r...N 30 E 2 E N 00 A A N 03 07 m Fi.3-3 -145 w 4.C I. N T 3 Ei p/ E S I I I I I I I II -3 E-c0 02 04 WII rrO- Nr .~H,.. A ~~’ h i FL.A3 14 WND PIOSMLITYt

  6. Edwards AFB, California. Range Reference Atmosphere 0-70 KM Altitude

    DTIC Science & Technology

    1983-08-01

    329. 16.000 3.34 4.62 .2165 5.05. 5.01 8.02 4.32 .70 322 . 27.000 -. 62 3.49 .2350 3.12 3.75 5.36 2.73 1.05 305. 28.000 -3.96 2.85 .2846 1.99 3.uj 5.56...8.15 2.62 -. 0465 .64 1.83 8.42 2.48 .23 322 . 22.00.0 -9.39 2.63 -. 1271 .49 1.72 9.57 2.59 .22 316. 23.000 -10.61 2.69 -. 0822 .35 1.67 10.76 2.63...99.999 99.999 999.99 210.12 3.Z2 -. 06 999.99 99.99 999.99 0. 322 . 19.000 99.999 99.999 999.99 212.18 2.44 .05 999.99 99.99 999.91 0. 319. 20.000 99.999

  7. Range Reference Atmosphere 0-70 km Altitude, Cape Canaveral, Florida

    DTIC Science & Technology

    1983-02-01

    B. Scope of the Range Reference Atmosphere and Arrangement of Tables ................. 1 C. Data Quality Control Procedures ............ 2 D ...Coordinate System and Computation of Statistical Parameters ....................... 8 C. Statistical Wind Models ...................... . 10 D ...Levels ............................. 30 C. Computation of Statistical Parameters for Tables II and III ........................... 35 D . Derived Monthly

  8. Simulation of CO2 release at 800 km altitude

    NASA Astrophysics Data System (ADS)

    Setayesh, A.

    1993-08-01

    The SOCRATES contamination-interaction code has been used to simulate the reactions of 0 + CO2 yields CO2(v) + O, O + CO2 - CO(v) + O2, and CO2 + H - CO + OH(v) at an altitude of 800 km in both ram and wake directions of the spacecraft. These simulations show that the radiation from these reactions can be measurable for the parameters which have been used in these calculations. The investigation carries out the simulations as much as 30 km from the spacecraft. The radiative intensity of CO(v) and OH(v) show the highest and lowest, respectively.

  9. Transport System for Delivery Tourists At Altitude 140 km

    NASA Technical Reports Server (NTRS)

    Bolonkin, Alexander

    2002-01-01

    The author offers a new method and installation for flight in space. This method uses the centrifugal force of a rotating circular cable that provides a means for the launch of a payload into outer space, to keep the fixed space stations at high altitudes (up to 200 km). The method may also be useful for landing to space bodies, for launching of the space ships (crafts), and for moving and accelerating other artificial apparatuses. The offered installation may be used as a propulsion system for space ships and/or probes. This system uses the material of any space body (i.e. stones) for acceleration and change of the space vehicle trajectory. The suggested system may be also used as a high capacity energy accumulator.

  10. Dosimetry of secondary cosmic radiation up to an altitude of 30 km.

    PubMed

    Wissmann, F; Burda, O; Khurana, S; Klages, T; Langner, F

    2014-10-01

    Dosimetric measurements in the field of secondary cosmic radiation were extensively made during the last years. Since the majority of these measurements were performed on-board passenger aircraft at altitudes between 10 and 12 km, measurements at higher altitudes are desirable for the verification of the legal dose assessment procedures for aircrew. A simple solution is to use a high-altitude balloon that reaches altitudes as high as 30 km. In this work, it is shown that the dose rate profile up to 30 km can be measured with acceptable uncertainties using a Si-detector. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. Electron density profiles probed by radio occultation of FORMOSAT-7/COSMIC-2 at 520 and 800 km altitude

    NASA Astrophysics Data System (ADS)

    Liu, J. Y.; Lin, C. Y.; Tsai, H. F.

    2015-02-01

    The FORMOSAT-7/COSMIC-2 (F7/C2) will ultimately place 12 satellites in orbit with two launches with 24° inclination and 520 km altitude in 2016 and with 72° inclination and 800 km altitude in 2019. In this study, we examine the electron density probed at the two satellite altitudes 500 and 800 km by means of FORMOSAT-3/COSMIC (F3/C) observations at the packing orbit 500 km altitude and mission orbit 800 km altitude, as well as observing system simulation experiments (OSSE). The electron density derived from 500 and 800 km satellite altitude of the F3/C observation and the OSSE confirm that the standard Abel inversion can correctly derive the electron density profile.

  12. Observations of neutral wind profiles between 115- and 175-km altitude in the dayside auroral oval

    NASA Technical Reports Server (NTRS)

    Pereira, E.; Kelley, M. C.; Rees, D.; Fuller-Rowell, T. J.; Mikkelsen, I. S.; Jorgensen, T. S.

    1980-01-01

    Lithium trail neutral wind measurements have been made in the morning dayside auroral oval as a function of altitude. During all four experiments the winds displayed a large altitude shear. In the most extreme case the wind at 135-km altitude was toward the south at 210 m/s, and at 185-km altitude toward the northwest at 170 m/s. A one-dimensional numerical solution to the Navier Stokes equation including an initial steady-state wind profile, viscosity, pressure gradient, Lorenz force and the Coriolis force was made in order to study the effect of auroral processes on the neutral atmosphere. Since electric fields and plasma density were measured, the Lorenz force could be modeled with reasonable accuracy. The pressure gradient was determined in an iterative way as a best fit to the observations. Within the limitations of a one-dimensional model the numerical solution is in reasonable agreement with one of the observations, which is applicable to such a modeling, and indicates that both Lorenz forces and pressure gradients due to auroral processes are required to explain the observation.

  13. Extending the Purple Crow Lidar Temperature Climatology Above 100 km Altitude Using an Inversion Approach

    NASA Astrophysics Data System (ADS)

    Jalali, A.; Sica, R. J.; Argall, S.; McCullough, E. M.

    2013-12-01

    Temperature retrievals from Rayleigh-scattering lidar measurements have been performed using the algorithm given by Chanin and Hauchecorne (1980; henceforth CH) for the last 3 decades. Recently Khanna et al. have presented an inversion approach to retrieve atmospheric temperature profiles. This method uses a nonlinear inversion method with a Monte Carlo technique to determine the statistical uncertainties for the retrieved nightly average temperature profiles. Using this approach, Purple Crow Lidar temperature profiles can now be extended 10 km higher in altitude compared to those calculated with the CH method, with reduced systematic uncertainty. Argall and Sica (2007) used the CH method to produce a climatology of the Purple Crow Lidar measurements from 1994 to 2004 which was compared with the CIRA-86 model. The CH method integrates temperatures downward, and requires the assumption of a 'seed' pressure at the highest altitude, taken from a model. Geophysical variation here, in the lower thermosphere, is sufficiently large to cause temperature retrievals to be unreliable for the top 10 or more km; uncertainties due to this pressure assumption cause the top two scale heights of temperatures from each profile to be discarded until the retrieval is no longer sensitive to the seed pressure. Khanna et al. (2012) use an inversion approach which allows the corrected lidar photocount profile to be integrated upward, as opposed to downward as required by the CH method. Khanna et al. (2012) showed that seeding the retrieval at the lowest instead of top height allows a much smaller uncertainty in the contribution of the seed pressure to the temperature compared to integrating from the top of the profile. Two other benefits to seeding the retrieval at the lower altitudes (around 30 km) include reduced geophysical variability, and the availability of routine pressure measurements from radiosondes. This presentation will show an extension of the Khanna et al. (2012) comparison

  14. GPS-aided gravimetry at 30 km altitude from a balloon-borne platform

    NASA Technical Reports Server (NTRS)

    Lazarewicz, Andrew R.; Evans, Alan G.

    1989-01-01

    A balloon-borne experiment, flown at 30 km altitude over New Mexico, was used to test dynamic differential Global Positioning System (GPS) tracking in support of gravimetry at high-altitudes. The experiment package contained a gravimeter (Vibrating String Accelerometer), a full complement of inertial instruments, a TI-4100 GPS receiver and a radar transponder. The flight was supported by two GPS receivers on the ground near the flight path. From the 8 hour flight, about a forty minute period was selected for analysis. Differential GPS phase measurements were used to estimate changes in position over the sample time interval, or average velocity. In addition to average velocity, differential positions and numerical averages of acceleration were obtained in three components. Gravitational acceleration was estimated by correcting for accelerations due to translational motion, ignoring all rotational effects.

  15. Sub-kilometer thermal plasma structure near 1750 km altitude in the polar cusp/cleft

    SciTech Connect

    Knudsen, D.J.; Whalen, B.A.; Yau, A.W.; Greffen, M.J.; Eriksson, A.I.; Lloyd, N.; Boehm, M.; Clemmons, J.; Blomberg, L.G.

    1994-08-15

    The authors present measurements made by the cold plasma analyzer (CPA) on the Freja satellite during an encounter with the polar cusp at an altitude of 1750 km. The instrument allows energy spectra of ions and electrons to be collected from 0 to 16 eV, with a time resolution of 1.2 sec. In addition the count rates can be sampled at 600/s to provide a much finer scaled measure of particle flux and energy flow into the instrument. The high time/spatial resolution this sampling rate affords allowed the observation of burst ion and electron events with time scales of 10 ms, and tens of percent variations.

  16. The O+ Density Trough at 5000 km Altitude in the Polar Cap

    NASA Technical Reports Server (NTRS)

    Zeng, W.; Horowitz, J. L.; Cravens, P. D.; Rich, F. J.; Moore, T. E.

    2003-01-01

    At altitudes near 5000 km over the Southern polar cap region of the terrestrial magnetospherehonosphere, the Thermal Ion Dynamics Experiment (TIDE) onboard the Polar satellite has observed O+ ion density trough regions, in which the O+ densities were at least one order of magnitude lower than the surrounding O+ densities. In the O+ demify trough regions, the estimated O+ densities were generally lower than 0.01 per cc. The boundaries between normal density level regions and the trough density regions were usually abrupt transitions. From December 1, 1997 to November 30, 1998, polar cap O+ troughs in Polar/TIDE observations occurred at a frequency of about 48%. Statistical examination of the Polar perigee observations from December 1 , 1997 to November 30, 1998 shows that the Polar perigee passes evenly covered the southern polar cap region, while the O+ density trough was always located on the nightside portion of the polar cap magnetospherehonosphere, and that invariant latitude spans of such troughs could be as large as 230 in extent. The trough occurrence displayed strong seasonal dependence; in the winter season (e.g. for July in the southern hemisphere) the O+ ion density trough occurrence frequency ranged up to 92%, while in the summer season (e.g. for January in the southern hemisphere) it decreased to as infrequent as 15%. The O+ ion density trough occurrence appeared relatively independent of the geomagnetic Kp index, and IMF Bz, By conditions. However, as suggested by the seasonal dependence, the O+ ion density trough occurrence was strongly related to the solar zenith angle (SZA). In the SZA range 500 to 1250, the trough occurrence increased monotonically with SZA. Also, case-by-case examinations of near-simultaneous O+ densities and vertical velocities observed by the DMSP satellite group orbiting at 840 km altitude indicate that the O+ density troughs observed at 5000 km altitude exhibit moderate correlation or anti-correlation with topside ionosphere

  17. Measured electric field in the vicinity of a thunderstorm system at an altitude of 37 km

    NASA Technical Reports Server (NTRS)

    Benbrook, J. R.; Kern, J. W.; Sheldon, W. R.

    1974-01-01

    A balloon-borne experiment to measure the atmospheric electric field was flown from the National Scientific Balloon Facility at Palestine, Texas, on July 10, 1973. The electric field and atmospheric conductivity were measured during ascent and for a 4-hour float period at 37-km altitude. Termination of the flight occurred near a thunderstorm line in west Texas. The perturbing influence of the thunderstorms on the electric field was observed at least 100 km from the storm line. The measured electric field is in reasonable agreement with calculations based on simple models of cloud structure and atmospheric conductivity. Large pulses in the measured electric field are interpreted as being the result of intracloud lightning.

  18. Simulation of CO2 release at 800 km altitude. Technical report

    SciTech Connect

    Setayesh, A.

    1993-08-31

    The SOCRATES contamination-interaction code has been used to simulate the reactions of O + CO2 --> CO2(v) + O, O + CO2 - CO(v) + O2, and CO2 + H - CO + OH(v) at an altitude of 800 km in both ram and wake directions of the spacecraft. These simulations show that the radiation from these reactions can be measurable for the parameters which have been used in these calculations. The investigation carries out the simulations as much as 30 km from the spacecraft. The radiative intensity of CO(v) and OH(v) show the highest and lowest, respectively. Gas plume, CO2, CO, and OH Emissions, Monte Carlo method, Rarefied flows.

  19. Neutral hydrogen flux measured at 100- to 200-km altitude in an electron aurora

    NASA Technical Reports Server (NTRS)

    Iglesias, G. E.; Anderson, H. R.

    1975-01-01

    Neutral hydrogen fluxes were measured at altitudes of 120-200 km by a rocket payload that also measured electron and proton fluxes and vector magnetic fields. An intense electron arc was crossed, while an upper limit to the flux of 0.5- to 20-keV protons was 1,000,000 per sq cm s sr keV. A neutral flux of 50,000,000 per sq cm s sr was observed, assuming hydrogen with greater than 1-keV energy, with greater north-south extent than the electron flux. Its pitch angle distribution was peaked toward 90 deg, tending toward isotropy in the center. This is fitted to a model describing spreading of an initial proton arc above 500 km.

  20. The O(+) Density Trough at 5000 km Altitude in the Polar Cap

    NASA Technical Reports Server (NTRS)

    Zeng, W.; Horwitz, J. L.; Craven, P. D.; Rich, F. J.; Moore, T. E.

    2004-01-01

    At altitudes near 5000 km over the southern polar cap region of the terrestrial magnetosphere/ionosphere, the Thermal Ion Dynamics Experiment (TIDE) on board the Polar satellite has observed O(+) ion density trough regions, in which the densities were at least one order of magnitude lower than the surrounding O(+) densities. In the 0" density trough regions, the estimated O+ densities were generally lower than 0.01 per cc. The boundaries between normal density level regions and the trough density regions were usually abrupt transitions. From 1 December 1997 to 30 November 1998, polar cap O(+) troughs in Polar/TIDE observations occurred at a frequency of about 48%. Statistical examination of the Polar perigee observations from 1 December 1997 to 30 November 1998 shows that the Polar perigee passes evenly covered the southern polar cap region, while the O(+) density trough was always located on the nightside portion of the polar cap magnetosphere/ionosphere, and that invariant latitude spans of such troughs could be as large as 23 deg. in extent. The trough occurrence displayed a strong seasonal dependence; in the winter season (e.g., for July in the Southern Hemisphere) the O(+) ion density trough occurrence frequency ranged up to 92%, while in the summer season (e.g., for January in the Southern Hemisphere) it decreased to as low as 15%. Our statistical results show that the trough occurrence was generally anticorrelated with solar wind dynamic pressure in the solar wind dynamic pressure range 0.8 - 2.6 nanopascal. The O(+) ion density trough occurrence appeared relatively independent of the geomagnetic Kp index, IMF Bz, and By conditions. However, as suggested by the seasonal dependence, the O(+) ion density trough occurrence was strongly related to the solar zenith angle (SZA). In the SZA range 50 deg. to 125 deg., the trough occurrence increased monotonically with SZA. In addition, we sought to determine consistent density and velocity signatures at lower

  1. Measuring Mars' Atmospheric Neutral Density from 160 to 320km altitude with the MGS Electron Reflectometer

    NASA Astrophysics Data System (ADS)

    Lillis, R. J.; Mitchell, D. L.; Lin, R. P.; Acuna, M. H.

    2003-12-01

    The Magnetometer/Electron Reflectometer (MAG/ER) experiment aboard Mars Global Surveyor (MGS) samples the local electron population's distribution in energy and pitch angle (angle between electron velocity and local magneticfield direction) at the mapping orbit altitude of ~400km. We develop a single-particle model of the electrons' interaction with the neutral atmosphere and motion along open field-lines connecting the solar wind to remnant crustal magnetization. Electron reflection from magnetic gradients and absorption due to inelastic collisons with atmospheric neutrals results in characteristic pitch angle (PA) distributions for open field lines. By assuming the validity of spherical harmonic expansions (Cain, Arkani-hamed) in the strongest field regions of Mars (such as Terra Sirenum), we trace the electron paths and fit these PA distributions to our model to constrain the scale height and base density of the neutral atmosphere in the interaction region, which is between 160 and 320km altitude. We analyse ~2 martian years of MGS mapping Orbit Data and present the first measurements of Mars' exospheric neutral density. We track density variations over season, latitude and solar cycle and compare with predictions from Mars Thermosphere Global Circulation Model (MTGCM) simulations and with MGS acceleromater data. Our results will help to constrain the upper boundaries of GCMs and assist orbital decay calculations for low-orbiting spacecraft, such as the 2005 Mars Reconnaissance Orbiter.

  2. Asymmetric Penetration of Shocked Solar Wind Down to 400-km Altitudes at Mars

    NASA Astrophysics Data System (ADS)

    Matsunaga, K.; Seki, K.; Hara, T.; Brain, D. A.

    2014-12-01

    The solar wind interaction with a planetary atmosphere produces the magnetic pile-up region near the planet. The Martian magnetic pile-up region prevents direct penetration of shocked solar wind (magnetosheath) plasma and the penetration boundary is typically located at altitudes above 800 km. Spacecraft measurements have shown, however, that magnetosheath plasma occasionally penetrates into low altitudes below 400 km. Here we used Mars Global Surveyor magnetic field and electron observations during the period from April 1999 to November 2006 to investigate the magnetosheath penetration events. We identified 240 events and found that both solar wind dynamic pressure (Psw) and the orientation of the interplanetary magnetic field (IMF) control the occurrence of the events. The magnetosheath penetration events during the low Psw periods tend to be distributed in low latitudes of the northern hemisphere where the crustal magnetic field is weak, while the event locations widely distributed in terms of the latitude under high Psw conditions. During the low Psw periods, a remarkable feature is that the observational probability is approximately 7 times larger during periods of the "away" IMF sector than during the "toward" sector. These results thus indicate that the magnetosheath penetrations into Martian upper atmosphere more often occur in the upward electric field hemisphere than in the downward electric field hemisphere. Large-amplitude undulation excited by the Kelvin-Helmholtz instability in the upward electric field hemisphere previously suggested from global hybrid simulation can be one of candidate processes to cause the asymmetric penetration during low Psw periods.

  3. Electron density profiles probed by radio occultation of FORMOSAT-7/COSMIC-2 at 520 and 800 km altitude

    NASA Astrophysics Data System (ADS)

    Liu, J. Y.; Lin, C. Y.; Tsai, H. F.

    2015-08-01

    The FORMOSAT-7/COSMIC-2 (F7/C2) will ultimately place 12 satellites in orbit with two launches with 24-28.5° inclination and 520-550 km altitude in 2016 and with 72° inclination and 720-750 km altitude in 2018. It would be very useful for the community to construct the global three-dimensional electron density structure by simultaneously combining the two launch observations for studying ionospheric structure and dynamics. However, to properly construct the global electron density structure, it is essential to know and evaluate differences between the ionospheric electron densities probed by the two launches. To mimic the F7/C2 observations, we examine the electron density probed at the two satellite altitudes 500 and 800 km by means of FORMOSAT-3/COSMIC (F3/C) observations at the parking orbit 500 km altitude and mission orbit 800 km altitude, as well as a corresponding observing system simulation experiment (OSSE). Observation and OSSE results show that the sounding geometries by satellite orbiting at 500 and 800 km altitudes can cause the overall differences in the electron density, the F2 peak electron density, and the F2 peak height of about 18-24, 12-28 %, and 7-19 km, respectively. Results confirm that the discrepancies mainly result from the sounding geometry and the grid (contour) bias of the electron density.

  4. Characterization of cosmic rays and direction dependence in the Polar Region up to 88 km altitude

    NASA Astrophysics Data System (ADS)

    Zábori, Balázs; Hirn, Attila; Deme, Sándor; Apáthy, István; Pázmándi, Tamás

    2016-02-01

    Aims: The sounding rocket experiment REM-RED was developed to operate on board the REXUS-17 rocket in order to measure the intensity of cosmic rays. The experiment was launched from the ESRANGE Space Center (68 °N, 21 °E) on the 17th of March 2015 at the beginning of the most intense geomagnetic storm within the preceding 10 years. The experiment provided the opportunity to measure the intensity of cosmic rays in the Polar Region up to an altitude of 88 km above sea level. Methods: The experiment employed Geiger-Müller (GM) counters oriented with their axes perpendicular to each other in order to measure the cosmic ray intensity during the flight of the rocket. This measurement setup allowed performing direction-sensitive measurements as well. During the ascent phase the rocket was spinning and hence stabilized along its longitudinal axis looking close to the zenith direction. This phase of the flight was used for studying the direction dependence of the charged particle component of the cosmic rays. Results: In comparison with earlier, similar rocket experiments performed with GM tubes at lower geomagnetic latitudes, significantly higher cosmic radiation flux was measured above 50 km. A non-isotropic behavior was found below 50 km and described in detail for the first time in the Polar Region. This behavior is in good agreement with the results of the TECHDOSE experiment that used the same type of GM tubes on board the BEXUS-14 stratospheric balloon.

  5. POLAR/TIDE Survey of Thermal O+ Characteristics near 5000km Altitude over the Polar Cap

    NASA Technical Reports Server (NTRS)

    Stevenson, B. A.; Horwitz, J. L.; Su, Y. J.; Elliott, Heather A.; Comfort, Richard H.; Moore, Thomas E.; Giles, Barbara A.; Craven, Paul D.; Chandler, Michael O.; Pollock, Craig J.

    1998-01-01

    We analyze measurements of thermal 0+ parameters from the Thermal Ion Dynamics Experiment (TIDE) on POLAR for April - May, 1996 obtained near 5000 km altitude within the polar cap ionosphere - magnetosphere interface region. Certain aspects of O+ parameters in this region were explored by Su et. al. [1998]. In this report, we hope to extend our understanding of the O+ behavior by examining relationships of densities, parallel velocities, and temperatures to the convection velocities, IMF By and Bz components. Preliminary results with the convection velocities are currently being analyzed. In doing so, we are guided in part by the Cleft Ion Fountain paradigm and model developed by Horwitz and Lockwood [1985] which involves downward O+ flows in the polar magnetosphere.

  6. Ion density and temperature variations at altitude of 500 km during moderate seismic activity

    NASA Astrophysics Data System (ADS)

    Bardhan, Ananna; Khurana, M. S.; Bahal, B. M.; Aggarwal, Malini; Sharma, D. K.

    2017-02-01

    Ionospheric ions (O+ and H+) and temperature (Ti) as precursory parameters to seismic activity have been analysed from year 1995 till 1998, using SROSS-C2 (average altitude range of ∼500 km) satellite measurements for moderate magnitude earthquakes. The details of seismic events during this period are downloaded from United State Geological Survey (USGS) and National Earthquake Information Centre (NEIC) website. 13 seismic events of moderate magnitude (M = 4-5.5) from 1995 to 1998, using SROSS-C2 satellite measurements have been analysed. During seismic affected period, considerable decrease in the density of heavier ion - O+ and increase in the ion temperature (Ti) is observed during all the selected events. Lighter ion - H+ doesn't show any significant change. Electric field and electromagnetic emissions generated due to seismogenic activity could be the plausible initializing agents responsible for change in ion concentration and temperature values during these events.

  7. Detection of EUV/Soft X-ray bremsstrahlung emission at terrestrial altitudes above 750 km

    NASA Astrophysics Data System (ADS)

    Katsiyannis, A.; Dominique, M.; De Keyser, J.; Berghmans, D.; Michel, K.; Dammasch, I. E.; Borremans, K.; De Donder, E.; Ben Moussa, A.

    2015-12-01

    LYRA is a fast radiometer on-board the PROBA-2 mission designed to observe the solar activity from UV to Soft X-rays and consists of three redundant units of four different optical bandpasses each. Since the start of operation in 2010, LYRA regularly observes disturbances with a characteristic signature that have no direct solar origin. Instead the frequency of occurrence correlates with the ApA_p index of geomagnetic activity on Earth's surface and the location of these detections coincides with the McIlwain L ≈ 3 zon. By comparing the wavelength sensitivity of the main PROBA-2 instruments, the wavelength range of the detected photons can be narrowed down to the range of 0.07-1 KeV (1-17 nm) and the altitudes of their source to those above PROBA-2's orbit (~750 km). A discussion on the magnetospheric origins of this emission is included.

  8. Asymmetric penetration of shocked solar wind down to 400 km altitudes at Mars

    NASA Astrophysics Data System (ADS)

    Matsunaga, Kazunari; Seki, Kanako; Hara, Takuya; Brain, David A.

    2015-08-01

    The penetration boundary of shocked solar wind (magnetosheath) into the Martian upper atmosphere is typically located at altitudes above 800 km. However, magnetosheath plasma occasionally penetrates into low altitudes below 400 km. Here we used Mars Global Surveyor magnetic field and electron observations from April 1999 to November 2006 to investigate the magnetosheath penetration events. We identified 1145 events and found that both solar wind dynamic pressure (Pdyn) and the orientation of the interplanetary magnetic field (IMF) control the occurrence of the events. The magnetosheath penetration events during low Pdyn periods tend to be distributed in low latitudes of the northern hemisphere or where the crustal magnetic field is weak, while the event locations are widely distributed in terms of the latitude under high Pdyn conditions. During low Pdyn periods, a remarkable feature is that the observational probability is approximately 2.4 times larger during periods of the "away" IMF sector than during the "toward" sector. The northern hemisphere during the away sector corresponds to the upward electric field hemisphere due to the convection of draping solar wind origin magnetic flux tubes. These results thus indicate that the magnetosheath penetrations into Martian upper atmosphere more often occur in the upward electric field hemisphere than the downward hemisphere during low Pdyn periods. Large-amplitude undulation excited by the Kelvin-Helmholtz instability in the upward electric field hemisphere is a candidate process to cause the asymmetric penetration during low Pdyn periods. Another possibility might be the mirror-mode instability by the asymmetric distribution of planetary pickup ions.

  9. 28 CFR 0.70 - General functions.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 28 Judicial Administration 1 2010-07-01 2010-07-01 false General functions. 0.70 Section 0.70 Judicial Administration DEPARTMENT OF JUSTICE ORGANIZATION OF THE DEPARTMENT OF JUSTICE Tax Division § 0.70 General functions. The following functions are assigned to and shall be conducted, handled, or supervised...

  10. Recent Pulsed Airborne Lidar measurements of Atmospheric CO2 Column Absorption to 13 km altitudes

    NASA Astrophysics Data System (ADS)

    Abshire, J. B.; Riris, H.; Allan, G. R.; Weaver, C. J.; Mao, J.; Hasselbrack, W.; Sun, X.; Rodriguez, M. R.

    2010-12-01

    We have developed a lidar technique for measuring atmospheric CO2 concentrations as a candidate for NASA’s ASCENDS mission. It uses pulsed laser transmitters to simultaneously measure a CO2 absorption line in the 1570 nm band, O2 extinction in the Oxygen A-band and surface height and backscatter. The lidar measures the energy and time of flight of the laser echoes reflected from the atmosphere and surface. The lasers step in wavelength across the CO2 line and an O2 line pair during the measurement. The receiver uses a telescope and photon counting detectors, and measures the time resolved backscatter of the laser echoes. Signal processing is used to isolate the laser echo signals from the surface, estimate their range, and reject laser photons scattered in the atmosphere. The gas extinction and column densities for the CO2 and O2 gases are estimated via the IPDA technique. We developed a lidar to demonstrate the CO2 measurement from aricraft. The lidar steps the pulsed laser’s wavelength across a selected CO2 line with 20 or 30 steps per scan. The line scan rate is 450 Hz and laser pulse widths are 1 usec. The time resolved laser backscatter is collected by a 20 cm telescope, detected by a photomultiplier and is recorded by a photon counting system. During July and August 2009 we made 5 two hour long flights while installed on the NASA Glenn Lear-25 aircraft. We measured the atmospheric CO2 absorption and line shapes using the 1572.33 nm CO2 line. Measurements were made at stepped altitudes from 3-13 km over a variety of surfaces in Nebraska, Illinois, the SGP ARM site, and near and over the Chesapeake Bay. Strong laser signals and clear line shapes were observed at all altitudes, and some measurements were made through thin clouds. The Oklahoma and east coast flights were coordinated with the NASA LaRC/ITT CO2 lidar on their UC-12 aircraft, a LaRC in-situ CO2 sensor, and the Oklahoma flights also included a JPL CO2 lidar on a Twin Otter aircraft. Ed Browell

  11. Global Investigation of the Mg Atom and ion Layers using SCIAMACHY/Envisat Observations between 70 km and 150 km Altitude and WACCM-MG Model Results

    NASA Technical Reports Server (NTRS)

    Langowski, M.; vonSavigny, C.; Burrows, J. P.; Feng, W.; Plane, J. M. C.; Marsh, D. R.; Janches, Diego; Sinnhuber, M.; Aikin, A. C.

    2014-01-01

    Mg and Mg+ concentration fields in the upper mesosphere/lower thermosphere (UMLT) region are retrieved from SCIAMACHY/Envisat limb measurements of Mg and Mg+ dayglow emissions using a 2-D tomographic retrieval approach. The time series of monthly means of Mg and Mg+ for number density as well as vertical column density in different latitudinal regions are shown. Data from the limb mesosphere-thermosphere mode of SCIAMACHY/Envisat are used, which covers the 50 km to 150 km altitude region with a vertical sampling of 3.3 km and a highest latitude of 82 deg. The high latitudes are not covered in the winter months, because there is no dayglow emission during polar night. The measurements were performed every 14 days from mid-2008 until April 2012. Mg profiles show a peak at around 90 km altitude with a density between 750 cm(exp-3) and 2000 cm(exp-3). Mg does not show strong seasonal variation at mid-latitudes. The Mg+ peak occurs 5-15 km above the neutral Mg peak at 95-105 km. Furthermore, the ions show a significant seasonal cycle with a summer maximum in both hemispheres at mid- and high-latitudes. The strongest seasonal variations of the ions are observed at mid-latitudes between 20-40 deg and densities at the peak altitude range from 500 cm(exp-3) to 6000 cm(exp-3). The peak altitude of the ions shows a latitudinal dependence with a maximum at mid-latitudes that is up to 10 km higher than the peak altitude at the equator. The SCIAMACHY measurements are compared to other measurements and WACCM model results. In contrast to the SCIAMACHY results, the WACCM results show a strong seasonal variability for Mg with a winter maximum, which is not observable by SCIAMACHY, and globally higher peak densities. Although the peak densities do not agree the vertical column densities agree, since SCIAMACHY results show a wider vertical profile. The agreement of SCIAMACHY and WACCM results is much better for Mg+, showing the same seasonality and similar peak densities. However

  12. Diurnal observations of HCl altitude variation in the 70-100 km mesosphere of Venus

    NASA Astrophysics Data System (ADS)

    Sandor, Brad J.; Todd Clancy, R.

    2017-07-01

    First submm spectroscopic observations of the 625.9 GHz H35Cl absorption lines of the Venus dayside atmosphere were obtained with the James Clerk Maxwell Telescope (JCMT) on March 2, 2013. These data, which support retrieval of HCl altitude distributions in the Venus mesosphere (70-100 km), are presented here and compared with previously reported JCMT observations of Venus nightside HCl (Sandor et al., 2012). The measured dayside profile agrees with that of the nightside, indicating no diurnal variation is present. More specifically, the nightside spectra revealed a secular decrease of upper mesospheric HCl between observations one month apart, at fixed latitude and local time. The dayside profile reported here presents upper mesospheric abundances that are bracketed by the two previously measured nightside profiles, indicating that if diurnal variation is present, it must be weaker than the secular variations occurring at fixed local time. The previous study, which measured nightside HCl abundances above 85 km to be much smaller than predicted from photochemical modeling, suggested a dynamical explanation for the disagreement wherein nightside downwelling associated with the SubSolar to AntiSolar (SSAS) atmospheric circulation might suppress upper mesospheric abundances predicted purely from photochemistry. However a straightforward prediction from the proposed mechanism is that HCl abundance on the dayside, where the SSAS drives upward rather than downward transport should at least agree with, and perhaps exceed that of the photochemical model. The finding that dayside HCl abundance agrees with that of the nightside, hence also is much smaller than that of the model shows the SSAS hypothesis to be incorrect.

  13. Polar Observations of Properties of H+ and O+ Conics in the Cusp Near 5300 km Altitude

    NASA Technical Reports Server (NTRS)

    Hirahara, M.; Horwitz, J. L.; Moore, T. E.; Chandler, M. O.; Giles, B. L.; Craven, P. D.; Pollock, C. L.

    1996-01-01

    Observations by the thermal ion dynamics experiment (TIDE) on POLAR are used to explore features of low-energy ionospheric ion conical distributions at approximately 5300 km altitude over the southern cusp under different interplanetary magnetic field (IMF) conditions with negative and positive B(sub z) components. The properties are summarized as follows: (1) At the edge upstream of the convection in the cusp, the energy of outflowing ion distributions abruptly increased from a few eV to approximately 100 eV; (2) The angular distributions also abruptly changed from rammed < approximately 5 eV polar wind distributions to approximately 10-100 eV conics; (3) These conic signatures gradually gave way again to polar wind components further downstream of the cusp; (4) The uppermost energy of the detected O+ was larger than that of H+, while the density and flux of O+ were lower than those of H+; (5) The cone angles for both light and heavy ion conics were largest for the upstream region of the convection; (6) Cone angles are wider for O+ than H+; (7) The cone angles as well as the conic energies gradually decreased in the convection direction; (8) The UFI beams and conics were sometimes observed alternately, particularly for H+, and (9) In some cases, the distinct ion conic bursts occurred multiple times during a single cusp crossing.

  14. Energy status and oxidation reduction status in rat liver at high altitude /3.8 km/

    NASA Technical Reports Server (NTRS)

    Reed, R. D.; Pace, N.

    1980-01-01

    Adult male rats were exposed to 3.8-km altitude for intervals ranging from 1 h-60 d. Liver samples were taken under light ether anesthesia and were examined by enzymatic analyses. Within 1-6 h of hypoxic exposure, ATP levels decreased while ADP and AMP levels increased, producing a fall in calculated ATP/ADP and adenylate charge ratios. Concurrently, lactate/pyruvate and alpha-glycerophosphate/dihydroxyacetone phosphate ratios increased markedly. Direct measurements of cellular pyridine nucleotides indicated increased NADH/NAD and NADPH/NADP ratios. Levels of total adenosine phosphates and pyridine nucleotides decreased in a significant accompanying response. Many metabolite levels and calculated ratios returned to near-normal values within 1 week of exposure, indicating secondary intracellular adjustments to hypoxic stress; however, persistence of that stress is reflected in lactate concentrations and both substrate redox ratios. Results support and explore concepts that increased oxidation-reduction status and decreased energy status are primary events during hypoxia.

  15. Energy status and oxidation reduction status in rat liver at high altitude /3.8 km/

    NASA Technical Reports Server (NTRS)

    Reed, R. D.; Pace, N.

    1980-01-01

    Adult male rats were exposed to 3.8-km altitude for intervals ranging from 1 h-60 d. Liver samples were taken under light ether anesthesia and were examined by enzymatic analyses. Within 1-6 h of hypoxic exposure, ATP levels decreased while ADP and AMP levels increased, producing a fall in calculated ATP/ADP and adenylate charge ratios. Concurrently, lactate/pyruvate and alpha-glycerophosphate/dihydroxyacetone phosphate ratios increased markedly. Direct measurements of cellular pyridine nucleotides indicated increased NADH/NAD and NADPH/NADP ratios. Levels of total adenosine phosphates and pyridine nucleotides decreased in a significant accompanying response. Many metabolite levels and calculated ratios returned to near-normal values within 1 week of exposure, indicating secondary intracellular adjustments to hypoxic stress; however, persistence of that stress is reflected in lactate concentrations and both substrate redox ratios. Results support and explore concepts that increased oxidation-reduction status and decreased energy status are primary events during hypoxia.

  16. The distribution of high altitude (70km) ice clouds in the Mars atmosphere from MGS TES limb radiance measurements

    NASA Astrophysics Data System (ADS)

    Clancy, T.; Wolff, M.

    One of the more interesting aspects of the atmospheric temperature profiles retrieved during the Pathfinder descent entry was the detection of cold 80km altitude temperatures below the saturation conditions for CO2 ice formation (Schofield et al., 1997). Disk average measurements of 70-80 km altitudes temperatures from ground-based sub-millimeter CO line observations are only 20K above CO2 saturation temperatures around the Mars Ls = 0 and 180 equinoctial seasons (Clancy, 1999). Clancy and Sandor (1998) suggested the relatively frequent occurrence of CO2 ice clouds in the 70-80 km altitude region, on the basis of the observed cold temperatures, Pathfinder images of blue (small size) ice clouds in the predawn sky, and Mariner 6 and 7 near-IR (4.3 micron) identification of CO2 ice in equatorial limb tangent views around Ls=200 in 1969 (Herr and Pimental, 1970). Before MGS observations, it remained unclear whether CO2 or water ice aerosols are ever present at >60km altitudes. Certainly dust aerosols had been identified at such high altitudes in Mariner 9 (Anderson and Leovy, 1978) and Viking (Jaquin et al., 1986) limb imaging, associated with the 1971 and 1977 global dust storms. The highest detached ice cloud identified from Viking limb data occurred at 55 km tangent altitude, at 16S, 72W and Ls = 176 (Jaquin et al., 1986; recently modeled by Montmessin et al., 2002). This seasonal period and location is actually fairly consistent with 70-80 km detached limb clouds that are observed prominently in the TES solarband limb scans, and appear restricted to fairly specific locations and seasons. The character of these high altitude limb clouds is displayed as a strong peak in scattered light is presented at 70-80 km altitudes, which is not resolved by the TES limb vertical resolution of ˜ 10 km and not detected in the coincident TES thermal IR spectral radiances. It is possible that co-adding of all limb IR spectra associated with TES solarband detections of these clouds

  17. Equatorial ionosphere observations from ionosonde satellite at an altitude of 350 km

    NASA Astrophysics Data System (ADS)

    Kotonaeva, Nadezhda; Danilkin, Nick

    Experimental study of the ionosphere from a MIR MAN SPACE STATUON (MMSS) was held in 1999. The new and interesting information was obtained in the study of the equatorial ionosphere. Critical frequencies and plasma frequencies distributions along the orbit at an altitude of MMSS had the appearance of two distinct peaks (crests) on both sides of the geomagnetic equator during the afternoon and evening local time. This corresponds to a typical daily distribution of plasma frequencies in areas of the equatorial anomaly (EA). The values of the critical frequency on the tops of EA "crest" exceeded the upper limit (16 MHz) of the ionosonde frequency often. In many cases, the measured values significantly exceeded the forecast model IRI. Analysis of the daytime values of the critical frequency on the tops of EA "crests" showed their approximate equality in the peaks of the southern and northern "crests". General analysis of the location of EA "crests" vertices during a night local time in the 1999 spring showed that the coordinates of the "crest" maxima are consistent with the finding of the geomagnetic equator, which corresponds to the theoretical predictions of the model provisions and IRI. MMSS was often lower than the height of the ionosphere maximum near the EA existence. At that time, satellite ionograms were recorded with previously unknown continuous trace of a characteristic shape with large group delay. This group delay is increasing monotonically with frequency increase. The trace was called "retardation of the lower trace" (RLT). The reason for it appearance is the oblique propagation of radio waves in a wide frequency range with the return to the satellite. A special kind of trajectory can be explained by large gradients of the electron density in a region of signal propagation. Gradients of plasma frequencies at the MMSS heights causing RLT were evaluated by a method of a trajectory synthesis. In the daytime they do not exceed 1 MHz / 100km. In the evening

  18. Dayside and nightside magnetic field responses at 780 km altitude to dayside reconnection

    NASA Astrophysics Data System (ADS)

    Snekvik, K.; Østgaard, N.; Tenfjord, P.; Reistad, J. P.; Laundal, K. M.; Milan, S. E.; Haaland, S. E.

    2017-02-01

    During southward interplanetary magnetic field, dayside reconnection will drive the Dungey cycle in the magnetosphere, which is manifested as a two-cell convection pattern in the ionosphere. We address the response of the ionospheric convection to changes in the dayside reconnection rate by examining magnetic field perturbations at 780 km altitude. The Active Magnetosphere and Planetary Electrodynamics Response Experiment data products derived from the Iridium constellation provide global maps of the magnetic field perturbations. Cluster data just upstream of the Earth's bow shock have been used to estimate the dayside reconnection rate. By using a statistical model where the magnetic field can respond on several time scales, we confirm previous reports of an almost immediate response both near noon and near midnight combined with a 10-20 min reconfiguration time of the two-cell convection pattern. The response of the ionospheric convection has been associated with the expansion of the polar cap boundary in the Cowley-Lockwood paradigm. In the original formulation of this paradigm the expansion spreads from noon to midnight in 15-20 min. However, also an immediate global response has been shown to be consistent with the paradigm when the previous dayside reconnection history is considered. In this paper we present a new explanation for how the immediate response can be accommodated in the Cowley-Lockwood paradigm. The new explanation is based on how MHD waves propagate in the magnetospheric lobes when newly reconnected open flux tubes are added to the lobes, and the magnetopause flaring angle increases.

  19. Dayside and nightside magnetic field responses at 780 km altitude to dayside reconnection.

    NASA Astrophysics Data System (ADS)

    Snekvik, Kristian; Østgaard, Nikolai; Tenfjord, Paul; Petter Reistad, Jone; Magnus Laundal, Karl; Milan, Stephen E.; Haaland, Stein E.

    2017-04-01

    During southward IMF, dayside reconnection will drive the Dungey cycle in the Earth's magnetosphere, which is manifested as a two cell convection pattern in the ionosphere. We address the response of the ionospheric convection to changes in the dayside reconnection rate. Previous studies have reported two apparently contradicting results. The first is that the ionospheric convection responds within one minute both near noon and near midnight. The second is that the response is 10-20 minutes delayed near midnight compared to near noon. To test these apparently contradicting scenarios, we have performed a statistical investigation of the response by examining the magnetic field perturbations at 780 km altitude due to dayside reconnection. The AMPERE data products derived from the Iridium constellation provide global maps of the disturbance magnetic field. The time development of the convection is modelled as the sum of an accelerating force and a decelerating force. Furthermore, the accelerating force is parametrised as a linear sum of past reconnection rates, while the decelerating force is proportional to the convection itself. This results in an asymptotic model which gradually reaches a steady-state value. By fitting the data to the model, we confirm previous reports of an almost immediate response both near noon and near midnight combined with a 10-20 minutes reconfiguration time of the two cell convection pattern. The e-folding time of the asymptotic model was found to be about 40 minutes. We present a new explanation of the response and reconfiguration times based on how MHD waves propagate in the magnetospheric lobes when newly reconnected open flux tubes are added to the lobes, and the magnetopause flaring angle increases.

  20. The Distribution of High Altitude (70KM) Ice Clouds in the Mars Atmospere from MGS TES and MOC LIMB Observations

    NASA Astrophysics Data System (ADS)

    Clancy, R. T.; Wolff, M.; Whitney, B.; Cantor, B.

    2004-11-01

    The Pathfinder descent entry detected extremely cold temperatures at 70-100 km altitudes (Schofield et al., 1997), suggesting the possibility of frequent CO2 ice cloud occurrence in the 70-80 km altitude region (Clancy and Sandor, 1998). However, prior to recent MGS limb measurements, it remained unclear whether CO2 or water ice aerosols are ever present at >60 km altitudes. Dust aerosols have been identified at such high altitudes in Mariner 9 (Anderson and Leovy, 1978), Viking (Jaquin et al., 1986), and MGS limb measurements (Clancy, 2003), associated with the 1971, 1977, and 2001 planet-encircling dust storms, respectively. The highest detached ice cloud identified from Viking limb data occurred at a projected tangent altitude of 55km, at 16S, 72W and Ls = 176° (Jaquin et al., 1986; recently modeled by Montmessin et al., 2002). The seasonal period and location of this detached limb cloud appears consistent with 55-75 km detached limb clouds that we have observed as prominent in MGS TES solarband limb scans and MGS MOC wide-angle (WA) limb images (1-3 pm local times). Their occurrence frequency approaches unity at the beginning and end of the aphelion northern summer season on Mars (centered at Ls =30° and 150° ), where they are confined to equatorial (15S-15N) latitudes and two relatively narrow longitude ranges (330-20W and 50-120W). Cloud altitudes of 65-75km are derived from the distribution of projected limb heights. Peak optical (visible) depths are quite significant (0.01) for the low pressure region of formation ( 1 microbar). It remains unclear as to their composition (water or CO2), although coadded MGS thermal IR spectra indicate potential for water ice identification and particle size information. We will present the spatial and temporal distribution of these mesospheric clouds indicated in the MSG TES and MOC visible limb data, and derived vertical profiles of optical depth and particle size based upon a monte carlo spherical RT analysis of the

  1. Seasonal variations of NO and O3 at altitudes of 18.3 and 21.3 km

    NASA Technical Reports Server (NTRS)

    Loewenstein, M.; Savage, H. F.; Whitten, R. C.

    1975-01-01

    Nitric oxide and ozone concentrations have been measured in situ from a high-altitude research aircraft. Data which show the variations of NO and O3 with the time of year are presented for altitudes of 18.3 and 21.3 km. The extreme values of the observed NO concentrations at 21.3 km are 1.2 billion per cu cm in summer and 0.2 billion per cu cm in winter. At 18.3 km the extreme values are 1.6 billion per cu cm in summer and 0.1 billion per cu cm in winter. The smoothed NO seasonal data show a variation of about a factor of 2.5 at 21.3 km and a factor of 4 at 18.3 km. The ozone data show the generally expected magnitude and seasonal variation. We have used a photochemical model employing the measured ozone concentrations, the mean solar zenith angle, and seasonal HNO3 data reported by others to predict the seasonal NO variation at 20 km. The result is a summer-to-winter NO ratio of 2.5 which is in fair agreement with the observed ratios.

  2. Modeling Relativistic Electron Precipitation Bremsstrahlung X-Ray Intensities at 10-100 km Manned Vehicle Altitudes

    NASA Astrophysics Data System (ADS)

    Habash Krause, L.; Gilchrist, B. E.; Nishikawa, K.; Williams, A.

    2013-12-01

    Relativistic electron precipitation (REP) events occur when beams or bunches of relativistic electrons of magnetospheric origin enter the Earth's atmosphere, typically at auroral latitudes. REP events are associated with a variety of space weather effects, including production of transitional and bremsstrahlung radiation, catalytic depletion of stratospheric ozone, and scintillation of transionospheric radio waves. This study examines the intensities of x-rays produced at airliner, manned balloon, and suborbital Reusable Launch Vehicle (sRLV) altitudes. The monoenergetic beam is modeled in cylindrical symmetry using the paraxial ray equation. Bremsstrahlung photon production is calculated using the traditional Sauter-Elwert cross-section, providing x-ray emission spectra differential in energy and angle. Attenuation is computed for a plane-stratified standard atmosphere, and the loss processes include photoionization, Rayleigh and Compton scattering, electron-positron pair production, and photonuclear interaction. Peak altitudes of electron energy deposition and bremsstrahlung x-ray production were calculated for beams of energies from 1 MeV through 100 MeV. The altitude peak of bremsstrahlung deposition was consistently and significantly lower that that of the electron deposition due to the longer mean free paths of x-rays compared to electrons within the atmosphere. For example, for a nadir-directed monoenergetic 5 MeV beam, the peak deposition altitude was calculated to be 42 km, but the resulting bremmstrahlung deposition peaked at 25 km. This has implications for crew and passenger safety, especially with the growth of the space tourism industry that relies on sRLVs with a nominal apogee of 100 km. A survey of results covering the 1-100 MeV spectrum for the three altitude ranges of interest will be presented.

  3. Whistler and Z mode radio sounding of the magnetosphere at altitudes < 5000 km by RPI on IMAGE

    NASA Astrophysics Data System (ADS)

    Sonwalkar, V.; Li, J.; Carpenter, D.; Venkatasubramanian, A.; Benson, R.; Reinisch, B.

    Radio Plasma Imager (RPI) on the IMAGE satellite can be used for the whistler and Z mode radio sounding of the magnetosphere using the low end of its 3-kHz to 3-MHz sounding frequency range. During soundings with both 25.6-ms pulses and 3.2-ms pulses, whistler-mode echoes have been observed in (1) ``discrete,'' lightning-whistler-like forms, and in (2) diffuse, widely time-spread forms suggestive of mode coupling at the boundaries of density irregularities. Discrete echoes, observed at altitudes less than ≈ 5000 km both inside the plasmasphere and over the auroral and polar regions, are believed to be RPI signals reflected at the Earth-ionosphere boundary. Diffuse echoes have also been observed at altitudes less than 5000 km, being most common poleward of the plasmasphere. In regions poleward of the plasmasphere, diffuse Z-mode echoes were found to accompany both discrete and diffuse whistler-mode echoes 90% of the time, and were also present during 90% of the soundings when no whistler-mode echoes were detected. The upper frequency cutoff, identified as the upper hybrid frequency, of the Z mode echo, and the gyrofrequency, as estimated from the gap in the Z mode echo, are used to calculate the local plasma density. By comparing the measured dispersion of discrete echoes with that from ray tracing simulations, it is possible to determine the plasma density along the ray path as well as to determine the nonducted or ducted modes of propagation. The ray tracing simulations carried out for several cases indicated that the electron density varied between 50 to 1000 el/cc at ˜ 4000 km altitude and showed R-4.5 dependence with altitude. By comparing measured dispersion of diffuse echoes with that from ray tracing simulations, it is possible to determine the locations and spatial sizes of density irregularities responsible for diffuse echoes. In one case, 06 August 2000, simulation result indicated the presence of ˜ 10-100 m scale plasma irregularities within ˜2000

  4. Simultaneous retrieval of daytime O(3P) and O3 concentrations in the altitude interval 80 - 100 km.

    NASA Astrophysics Data System (ADS)

    Yankovsky, Valentine; Manuilova, Rada; Koval, Andrey

    2017-04-01

    We propose methods of simultaneously independent retrievals of the key components of Mesosphere and Lower Thermosphere (MLT) [O3] and [O(3P)]. The altitude profile of ozone concentration, [O3], can be measured by direct method of the measurement of absorbing radiation from the Sun or the stars in the UV range of the spectrum. However, this method is most often realized in twilight. Retrieval of daytime [O3] depends on a prior information about the O(3P) altitude profile. Vice versa, atomic oxygen concentration, [O(3P)], is usually retrieved from the measured values of [O3]. The problem of independent and simultaneous retrieval of [O3] and [O(3P)] can be solved by using individual proxy for each of the target component. Using a sensitivity study and uncertainty analysis of the contemporary model of O3 and O2 photolysis in the MLT, YM2011, we determined that populations of three excited electronic-vibrational levels O2(b1, v = 0, 1, 2) and of metastable O(1D) atom depend on [O(3P)] and [O3] concentrations. For [O(3P)] retrieval the following transitions should be used: O2(b1, v') -> O2(X3, v") which produce emissions: (a) at 780.4 nm in the band (v' = 2, v" = 2) and at 697.0 nm in the band (2, 1) with the uncertainty of retrieval smaller than 30% for the whole altitude range 80 - 100 km; (b) at 771.0 nm in the band (1, 1), 688.4 nm in the band (1, 0) and at 874.4 nm in the band (1, 2) with the uncertainty of retrieval about 30% above 90 km. For [O3] retrieval the following transitions should be used: O2(b1, v') -> O2(X3, v") which produce emissions: (c) at 762.1 nm in the band (0, 0) and at 864.7 nm in the band (0, 1) with the uncertainty of retrieval 20 - 25% for the altitude range 80 - 85 km and smaller than 20% in the interval 85 - 95 km; (d) in the line of O(1D) 630.0 nm with the uncertainty of retrieval 10 - 15% in the interval 80 - 95 km. Above 95 km the uncertainty of [O3] retrieval grows and reaches up to 80% at 100 km for all suggested proxies. For

  5. Nitric oxide and nitrogen dioxide content of whole-air samples obtained at altitudes from 12 to 30 km

    SciTech Connect

    Gallagher, C.C.; Forsberg, C.A.; Pieri, R.V.; Faucher, G.A.; Calo, J.M.

    1985-08-20

    Whole air samples were obtained in the stratosphere using a liquid helium-cooled cryosampler mounted on a balloon platform. Approximately 1 g mol of sample was obtained at each of three altitudes per balloon flight and was maintained at 4 K until desorption just prior to analysis. Samples were obtained at six altitudes ranging from 12 to 30 km and at five latitudes from 9 to 64/sup 0/. Nitric oxide and the sum of nitric oxide and nitrogen dioxide content of the samples were determined using two chemiluminescence analyzers. Results from flights conducted between 1977 and 1981 are correlated with atmospheric motions and other significant variables and evaluated in terms of both one- and two-dimensional models of the stratosphere.

  6. Modeling Relativistic Electron Precipitation Bremsstrahlung X-Ray Intensities at 10-100 km Manned Vehicle Altitudes

    NASA Technical Reports Server (NTRS)

    Krause, L. Habsh; Gilchrist, B. E.; Nishikawa, Ken-Ichi

    2013-01-01

    Relativisitic electron precipitation (REP) events occur when beams or bunches of relativistic electrons of magnetospheric origin enter the Earth's atmosphere, typically at auroral latitudes. REP events are associated with a variety of space weather effects, including production of transitional and bremsstrahlung radiation, catalytic depletion of stratospheric ozone, and scintillation of transionospheric radio waves. This study examines the intensities of x-rays produced at airliner, manned balloon, and space reuseable launch vehicles (sRLVs). The monoenergetic beam is modeled in cylindrical symetry using the paraxial ray equation. Bremsstrahlung photon production is calculated using the traditional Sauter-Elwert cross-section, providing x-ray emission spectra differential in energy and angle. Attenuation is computed for a plane-stratified standard atmosphere, and the loss processes include photoionization, Rayleigh and Compton scattering, electron-positron pair production, and photonuclear interaction. Peak altitudes of electron energy deposition and bremsstrahlung x-ray production were calculated for beams of energies from 1 MeV through 100 MeV. The altitude peak of bremsstrahlung deposition was consistently and significantly lower that that of the electron deposition due to the longer mean free paths of x-rays compared to electrons within the atmosphere. For example, for a nadir-directed monoenergetic 5 MeV beam, the peak deposition altitude was calculated to be 42 km, but the resulting bremsstrahlung deposition peaked at 25 km. This has implications for crew and passenger safety, especially with the growth of the space tourism industry. A survey of results covering the 1-100 MeV spectrum for the three altitude ranges of interest will be presented.

  7. Channel electron multiplier operated on a sounding rocket without a cryogenic vacuum pump from 120 - 75 km altitude

    NASA Astrophysics Data System (ADS)

    Dickson, S.; Gausa, M. A.; Robertson, S. H.; Sternovsky, Z.

    2012-12-01

    We demonstrate that a channel electron multiplier (CEM) can be operated on a sounding rocket in the pulse-counting mode from 120 km to 75 km altitude without the cryogenic evacuation used in the past. Evacuation of the CEM is provided only by aerodynamic flow around the rocket. This demonstration is motivated by the need for additional flights of mass spectrometers to clarify the fate of metallic compounds and ions ablated from micrometeorites and their possible role in the nucleation of noctilucent clouds. The CEMs were flown as guest instruments on the two sounding rockets of the CHAMPS (CHarge And mass of Meteoritic smoke ParticleS) rocket campaign which were launched into the mesosphere in October 2011 from Andøya Rocket Range, Norway. Modeling of the aerodynamic flow around the payload with Direct Simulation Monte-Carlo (DSMC) code showed that the pressure is reduced below ambient in the void beneath an aft-facing surface. An enclosure containing the CEM was placed above an aft-facing deck and a valve was opened on the downleg to expose the CEM to the aerodynamically evacuated region below. The CEM operated successfully from apogee down to ~75 km. A Pirani gauge confirmed pressures reduced to as low as 20% of ambient with the extent of reduction dependent upon altitude and velocity. Additional DSMC simulations indicate that there are alternate payload designs with improved aerodynamic pumping for forward mounted instruments such as mass spectrometers.

  8. Channel electron multiplier operated on a sounding rocket without a cryogenic vacuum pump from 120 to 80 km altitude

    NASA Astrophysics Data System (ADS)

    Dickson, Shannon; Gausa, Michael; Robertson, Scott; Sternovsky, Zoltan

    2013-04-01

    We demonstrate that a channel electron multiplier (CEM) can be operated on a sounding rocket in the pulse-counting mode from 120 km to 80 km altitude without the cryogenic evacuation used in the past. Evacuation of the CEM is provided only by aerodynamic flow around the rocket. This demonstration is motivated by the need for additional flights of mass spectrometers to clarify the fate of metallic compounds and ions ablated from micrometeorites and their possible role in the nucleation of noctilucent clouds. The CEMs were flown as guest instruments on two sounding rockets to the mesosphere. Modeling of the aerodynamic flow around the payload with Direct Simulation Monte-Carlo (DSMC) code showed that the pressure is reduced below ambient in the void behind (relative to the direction of motion) an aft-facing surface. An enclosure containing the CEM was placed forward of an aft-facing deck and a valve was opened during flight to expose the CEM to the aerodynamically evacuated region behind it. The CEM operated successfully from apogee down to ∼80 km. A Pirani gauge confirmed pressures reduced to as low as 20% of ambient with the extent of reduction dependent upon altitude and velocity. Additional DSMC simulations indicate that there are alternate payload designs with improved aerodynamic pumping for forward mounted instruments such as mass spectrometers.

  9. Relationship of O(+) Field-Aligned Flows and Densities to Convection Speed in the Polar Cap at 5000 km Altitude

    NASA Technical Reports Server (NTRS)

    Stevenson, B. A.; Horwitz, J. L.; Creel, B.; Elliott, H. A.; Comfort, R. H.; Su, Y. J.; Moore, T. E.; Craven, P. D.

    1999-01-01

    Measurements of thermal O(+) ion number fluxes, densities, field-aligned velocities, and convective velocities from the Thermal Ion Dynamics Experiment (TIDE) on POLAR obtained near 5000 km altitude over the Southern hemisphere are examined. We find that the O(+) parallel velocities and densities are strongly related to the convection speeds. The polar cap densities decrease rapidly with convection speed, with a linear least square fit formula to bin averaged data giving the relationship log(N(sub (sub _)O(+))) = -0.33* V(sub (sub _)conv)) + 0.07, with a linear regression coefficient of r = -0.96. The parallel bulk flow velocities are on average slightly downward (0 - 2 km/s) for V(sub (sub _)conv) < 2.5 km/s, but tend to be upward (0 - 4 km/s) for average V(sub (sub _)conv) > 2.5 km/s. We interpret these relationships in terms of the Cleft Ion Fountain paradigm [e.g., Horwitz and Lockwood, 1985]. The densities decline with convection speed owing to increased spreading and resulting dilution from the restricted cleft source over the polar cap area with convection speed. The parallel velocities tend to be downward for low convection speeds because they fall earthward after initial cleft injection at shorter distances into the polar cap for low convection speeds. At the higher convection speeds, the initially-upward flows are transported further into the polar cap and thus occupy a larger area of the polar cap.

  10. Relationship of O(+) Field-Aligned Flows and Densities to Convection Speed in the Polar Cap at 5000 km Altitude

    NASA Technical Reports Server (NTRS)

    Stevenson, B. A.; Horwitz, J. L.; Creel, B.; Elliott, H. A.; Comfort, R. H.; Su, Y. J.; Moore, T. E.; Craven, P. D.

    1999-01-01

    Measurements of thermal O(+) ion number fluxes, densities, field-aligned velocities, and convective velocities from the Thermal Ion Dynamics Experiment (TIDE) on POLAR obtained near 5000 km altitude over the Southern hemisphere are examined. We find that the O(+) parallel velocities and densities are strongly related to the convection speeds. The polar cap densities decrease rapidly with convection speed, with a linear least square fit formula to bin averaged data giving the relationship log(N(sub (sub _)O(+))) = -0.33* V(sub (sub _)conv)) + 0.07, with a linear regression coefficient of r = -0.96. The parallel bulk flow velocities are on average slightly downward (0 - 2 km/s) for V(sub (sub _)conv) < 2.5 km/s, but tend to be upward (0 - 4 km/s) for average V(sub (sub _)conv) > 2.5 km/s. We interpret these relationships in terms of the Cleft Ion Fountain paradigm [e.g., Horwitz and Lockwood, 1985]. The densities decline with convection speed owing to increased spreading and resulting dilution from the restricted cleft source over the polar cap area with convection speed. The parallel velocities tend to be downward for low convection speeds because they fall earthward after initial cleft injection at shorter distances into the polar cap for low convection speeds. At the higher convection speeds, the initially-upward flows are transported further into the polar cap and thus occupy a larger area of the polar cap.

  11. Cloud Microphysics in Hurricane Outflows: Observations in 'Bonnie' (1998) at 12 km Altitude

    NASA Technical Reports Server (NTRS)

    Pueschel, Rudolf F.; Hallett, J.; Strawa, A. W.; Ferry, G. V.; Bui, T. P.; Condon, Estelle P. (Technical Monitor)

    2000-01-01

    The water balance of a hurricane is controlled by boundary layer inflow, near vertical motion in the eyewall causing coalescence precipitation at above and residual ice precipitation at below freezing temperatures, and cirrus outflow at below -40 C aloft. In this paper we address the question of efficiency of water removal by this cirrus outflow which is important for the release of latent heat at high altitudes and its role in the dynamic flow at that level. During NASA's 1998 Convection and Moisture Experiment campaign we acquired microphysical outflow data in order to (1) determine the release and redistribution of latent heat near the top of hurricanes, (2) aid in TRMM algorithm development for remote sensing of precipitation, and (3) determine the optical/radiative characteristics of hurricane outflow. The data were acquired with Particle Measuring Systems two dimensional imaging spectrometers. On 23 August and again during the hurricane's landfall on 26 August, 1998, the NASA DC-8 aircraft penetrated hurricane 'Bonnie' four times each near 200 hPa pressure altitude. The eye crossing times were determined by (1) zero counts of cloud particles, (2) approximately 5 C increases in static and potential temperatures, and (3) minima in speeds and changes of direction of horizontal winds. The vertical winds showed shear between -6 m per second and +4 m per second and tangential winds approached 30 m per second in the eyewall. The particle volumes in the eyewall (determined by the pixels the particles shadowed in the direction of flight [x-direction] and normally to it by the number of diodes that they shadowed [y-direction]) ranged between 0.5 and 5.0 cubic centimeters per cubic meter. With a particle density near 0.2 g per cubic centimeter (determined from in situ melting and evaporation on a surface collector), the 1.0 g per meter corresponding mass of cloud ice ranged between 0.27 and 2.7 g per kilograms yielding horizontal fluxes between 8.1 and 81 g per square

  12. Cloud Microphysics in Hurricane Outflows: Observations in 'Bonnie' (1998) at 12 km Altitude

    NASA Technical Reports Server (NTRS)

    Pueschel, Rudolf F.; Hallett, J.; Strawa, A. W.; Ferry, G. V.; Bui, T. P.; Condon, Estelle P. (Technical Monitor)

    2000-01-01

    The water balance of a hurricane is controlled by boundary layer inflow, near vertical motion in the eyewall causing coalescence precipitation at above and residual ice precipitation at below freezing temperatures, and cirrus outflow at below -40 C aloft. In this paper we address the question of efficiency of water removal by this cirrus outflow which is important for the release of latent heat at high altitudes and its role in the dynamic flow at that level. During NASA's 1998 Convection and Moisture Experiment campaign we acquired microphysical outflow data in order to (1) determine the release and redistribution of latent heat near the top of hurricanes, (2) aid in TRMM algorithm development for remote sensing of precipitation, and (3) determine the optical/radiative characteristics of hurricane outflow. The data were acquired with Particle Measuring Systems two dimensional imaging spectrometers. On 23 August and again during the hurricane's landfall on 26 August, 1998, the NASA DC-8 aircraft penetrated hurricane 'Bonnie' four times each near 200 hPa pressure altitude. The eye crossing times were determined by (1) zero counts of cloud particles, (2) approximately 5 C increases in static and potential temperatures, and (3) minima in speeds and changes of direction of horizontal winds. The vertical winds showed shear between -6 m per second and +4 m per second and tangential winds approached 30 m per second in the eyewall. The particle volumes in the eyewall (determined by the pixels the particles shadowed in the direction of flight [x-direction] and normally to it by the number of diodes that they shadowed [y-direction]) ranged between 0.5 and 5.0 cubic centimeters per cubic meter. With a particle density near 0.2 g per cubic centimeter (determined from in situ melting and evaporation on a surface collector), the 1.0 g per meter corresponding mass of cloud ice ranged between 0.27 and 2.7 g per kilograms yielding horizontal fluxes between 8.1 and 81 g per square

  13. The latitudinal distribution of ozone to 35 km altitude from ECC ozonesonde observations, 1982-1990

    NASA Technical Reports Server (NTRS)

    Komhyr, W. D.; Oltmans, S. J.; Lathrop, J. A.; Kerr, J. B.; Matthews, W. A.

    1994-01-01

    Electrochemical concentration cell (ECC) ozone-sonde observations, made in recent years at ten stations whose locations range from the Arctic to Antarctica, have yielded a self-consistent ozone data base from which mean seasonal and annual latitudinal ozone vertical distributions to 35 km have been derived. Ozone measurement uncertainties are estimated, and results are presented in the Bass-Paur (1985) ozone absorption coefficient scale adopted for use with Dobson ozone spectrophotometers January 1, 1992. The data should be useful for comparison with model calculations of the global distribution of atmospheric ozone, for serving as apriori statistical information in deriving ozone vertical distributions from satellite and Umkehr observations, and for improving the satellite and Umkehr ozone inversion algorithms. Attention is drawn to similar results based on a less comprehensive data set published in Ozone in the Atmosphere, Proceedings of the 1988 Quadrennial Ozone Symposium where errors in data tabulations occurred for three of the stations due to inadvertent transposition of ozone partial pressure and air temperature values.

  14. Observations of HCl altitude dependence and temporal variation in the 70-100 km mesosphere of Venus

    NASA Astrophysics Data System (ADS)

    Sandor, Brad J.; Clancy, R. Todd

    2012-08-01

    Spectroscopically resolved observations of the 625.9 GHz H35Cl absorption lines were obtained with the James Clerk Maxwell Telescope on October 23, November 7, and December 5, 2010. The nightside atmosphere was observed on all three dates, and the dayside morning crescent was also observed on December 5. Shape of the pressure-broadened absorption constrains altitude distribution of HCl over 70-100 km. Retrieved abundances at 70-80 km are consistent with 74 km values reported by Krasnopolsky (Krasnopolsky, V.A. [2010]. Icarus 208, 539-547), and do not agree with smaller abundances measured at the North polar terminator with Venus Express (Vandaele, A.C. [2008]. J. Geophys. Res. 113(E00B23), 1-16). Observed HCl mixing ratios decrease rapidly with altitude above 80 km, with 90 km abundances decreased by a factor of two or more relative to those in the lower mesosphere. This behavior is distinctly different from photochemical model profiles, which predict 90 and 110 km mixing ratios only 10% and 25% smaller, respectively, than cloud top values. While model photochemistry indicates HCl should be the dominant chlorine reservoir in the mesosphere and lower thermosphere, observations show HCl abundance is less than half that of total chlorine above 90 km. It directly follows that at least one other chlorine containing molecule must be present in the upper mesosphere at abundances far higher than predicted, which in turn suggests chlorine chemistry in this region differs significantly from the current theoretical understanding. Above 85 km, the equatorial HCl abundances reported here are consistent with polar vortex values from Venus Express, suggesting that the unknown mechanism depleting HCl above 80 km at low latitudes may be important throughout the mesosphere at high latitude. The polar vortex (Venus Express) and equatorial nightside (this study) of Venus are regions of dynamical downwelling, such that downward transport of air from a thermospheric region of HCl

  15. POLAR Observations of Field Aligned O+ Flows at 5000 km Altitude Over the Polar Regions with Comparison to Auroral Images

    NASA Technical Reports Server (NTRS)

    Stevenson, B. A.; Horwitz, J. L.; Germany, G.; Craven, Paul D.; Moore, Thomas E.; Giles, B. L.; Parks, G. K.; Su, Y. J.

    2000-01-01

    Measurements of thermal 0+ ion parameters from the Thermal Ion Dynamics Experiment (TIDE) on POLAR obtained near 5000 km altitude are compared with auroral images from the Ultra Violet Imager (UVI), for southern perigee passes. Ion parameters, including parallel velocity, density, and flux are combined with multiple dayside and nightside auroral images to investigate relationships between O+ field aligned flows and the structure and brightness seen in the auroral forms. Results indicate field aligned upflowing O+ ions over regions of bright auroral activity and downward flows over dark regions. These and other relationships will be presented for several POLAR passes when both ion measurements and auroral images are observed under favorable conditions for comparison.

  16. Asymmetric penetration of solar wind perturbations down to 400-km altitudes at Mars observed by Mars Global Surveyor

    NASA Astrophysics Data System (ADS)

    Matsunaga, K.; Seki, K.; Hara, T.; Brain, D. A.

    2012-12-01

    Since Mars has no intrinsic global magnetic field, the exchange of energy, momentum, and material with the planet takes place through interaction between the solar wind and the Martin upper atmosphere. It is thought that solar wind encountering Mars can penetrate into the point where the solar wind dynamic pressure and the plasma thermal pressure in the Martin ionosphere are almost balanced and the solar wind flow is deflected around the boundary. However, the actual interaction can be complicated, since both plasma processes and the existence of crustal magnetic fields can modify the structure of the boundary. The Kelvin-Helmholtz (K-H) instability at the Martian ionopause is one of important candidate process to cause the modification. The dDistribution of ionopause surface waves generated by the K-H instability can should exhibit a clear asymmetry between hemispheres of upward and downward solar wind motional electric fields [e.g., Terada et al., 2002]. It is also suggested that the crustal magnetic fields can locally push the MPB (magnetic pileup boundary) upward [e.g., Brain et al., 2003]. It is also reported that the boundary between the solar wind and Martian ionosphere is located at an altitude of 380 km on average in the dayside [e.g., Mitchell et al., 2001]. However, this boundary location can change significantly depending on solar wind conditions. While it is considered that the solar wind can penetrate to lower altitudes than usual when the solar wind pressure is high, the frequency of the solar wind penetration and its quantitative dependence on the solar wind conditions are not yet well understood. In this study, we focused on penetration of solar wind electromagnetic disturbances, which are a characteristic feature of the shocked solar wind (magnetosheath), down to 400-km altitude at Mars. Using Mars Global Surveyor (MGS) data, we investigated the observational frequency and characteristics of the penetration events. We used data from the MGS

  17. Pulsed Airborne Lidar measurements of Atmospheric CO2 Column Absorption and Line Shapes from 3-13 km altitudes

    NASA Astrophysics Data System (ADS)

    Abshire, J. B.; Riris, H.; Allan, G. R.; Weaver, C. J.; Hasselbrack, W. E.; Sun, X.

    2009-12-01

    We have developed a lidar technique for measuring the tropospheric CO2 concentrations as a candidate for NASA’s planned ASCENDS mission. Our technique uses two pulsed laser transmitters allowing simultaneous measurement of a CO2 absorption line in the 1570 nm band, O2 extinction in the Oxygen A-band and surface height and backscatter. The lidar measures the energy and time of flight of the laser echoes reflected from the atmosphere and surface. The lasers are stepped in wavelength across the CO2 line and an O2 line region during the measurement. The receiver uses a telescope and photon counting detectors, and measures the background light and energies of the laser echoes from the surface along with scattering from any aerosols in the path. The gas extinction and column densities for the CO2 and O2 gases are estimated from the ratio of the on- and off- line signals via the DIAL technique. Time gating is used to isolate the laser echo signals from the surface, and to reject laser photons scattered in the atmosphere. We have developed an airborne lidar to demonstrate the CO2 measurement from the NASA Glenn Lear-25 aircraft. The airborne lidar steps the pulsed laser’s wavelength across a selected CO2 line with 20 steps per scan. The line scan rate is 450 Hz, laser pulse energy is 25 uJ and laser pulse widths are 1 usec. The time resolved laser backscatter is collected by a 20 cm telescope, detected by a photomultiplier and is recorded by a photon counting system. We made initial airborne measurements on flights during October and December 2008. Laser backscatter and absorption measurements were made over a variety of land and water surfaces and through thin and broken clouds. Atmospheric CO2 column measurements using the 1571.4, 1572.02 and 1572.33 nm CO2 lines. Two flights were made above the DOE SGP ARM site at altitudes from 3-8 km. These flights were coordinated with DOE investigators who flew an in-situ CO2 sensor on a Cessna aircraft under the path. The

  18. Pulsed Airborne Lidar measurements of Atmospheric CO2 Column Absorption and Line Shapes from 3-13 km altitudes

    NASA Astrophysics Data System (ADS)

    Abshire, James; Riris, Haris; Allan, Graham; Weaver, Clark; Mao, Jianping; Sun, Xiaoli; Hasselbrack, William

    2010-05-01

    US Department of Energy's (DOE) SGP ARM site at altitudes from 3-8 km. These flights were coordinated with DOE investigators who flew an in-situ CO2 sensor on a Cessna aircraft under the path. The increasing CO2 line absorptions with altitudes were evident and comparison with in-situ measurements showed agreements to 6 ppm. In spring 2009 we improved the aircraft's nadir window and during July and August we made 9 additional 2 hour long flights and measured the atmospheric CO2 absorption and line shapes using the 1572.33 nm CO2 line. Measurements were made at stepped altitudes from 3-13 km over a variety of surface types in Nebraska, Illinois, the SGP ARM site, and near and over the Chesapeake Bay in North Carolina and eastern Virginia. Strong laser signals and clear Co2 line shapes were observed at all altitudes, and some measurements were made through thin clouds. The flights over the ARM site were underflown with in-situ measurements made from the DOE Cessna. Analysis shows that the average signal levels follow predicted values, the altimetry measurements had an uncertainty of about 4 m, and that the average optical line depths follow the number density calculated from in-situ sensor readings. The Oklahoma and east coast flights were coordinated with a LaRC/ITT CO2 lidar on the LaRC UC-12 aircraft, a LaRC in-situ CO2 sensor, and the Oklahoma flights also included a JPL CO2 lidar on a Twin Otter aircraft. More details of the flights, measurements, analysis and scaling to space will be described in the presentation.

  19. Pulsed Airborne Lidar Measurements of Atmospheric CO2 Column Absorption and Line Shapes from 3-13 km Altitudes

    NASA Technical Reports Server (NTRS)

    Abshire, J. B.; Riris, H.; Allan, G. R.; Weaver, C.; Hasselbrack, W.; Sun, X.

    2009-01-01

    We have developed a lidar technique for measuring the tropospheric C02 concentrations as a candidate for NASA's planned ASCENDS mission. Our technique uses two pulsed laser transmitters allowing simultaneous measurement of a C02 absorption line in the 1570 nm band, 02 extinction in the Oxygen A-band and surface height and backscatter. The lidar measures the energy and time of flight of the laser echoes reflected from the atmosphere and surface. The lasers are stepped in wavelength across the C02 line and an 02 line region during the measurement. The receiver uses a telescope and photon counting detectors, and measures the background light and energies of the laser echoes from the surface along with scattering from any aerosols in the path. The gas extinction and column densities for the C02 and 02 gases are estimated from the ratio of the on- and off- line signals via the DIAL technique. Time gating is used to isolate the laser echo signals from the surface, and to reject laser photons scattered in the atmosphere. We have developed an airborne lidar to demonstrate the C02 measurement from the NASA Glenn Lear 25 aircraft. The airborne lidar steps the pulsed laser's wavelength across a selected C02 line with 20 steps per scan. The line scan rate is 450 Hz and laser pulse widths are I usec. The time resolved laser backscatter is collected by a 20 cm telescope, detected by a photomultiplier and is recorded by a photon counting system. We made initial airborne measurements on flights during October and December 2008. Laser backscatter and absorption measurements were made over a variety of land and water surfaces and through thin and broken clouds. Atmospheric C02 column measurements using the 1571.4, 1572.02 and 1572.33 nm C02 lines. Two flights were made above the DOE SGP ARM site at altitudes from 3-8 km. These nights were coordinated with DOE investigators who Hew an in-situ C02 sensor on a Cessna aircraft under the path. The increasing C02 line absorptions with

  20. Pulsed Airborne Lidar Measurements of Atmospheric CO2 Column Absorption and Line Shapes from 3-13 km Altitudes

    NASA Technical Reports Server (NTRS)

    Abshire, J. B.; Riris, H.; Allan, G. R.; Weaver, C.; Hasselbrack, W.; Sun, X.

    2009-01-01

    We have developed a lidar technique for measuring the tropospheric C02 concentrations as a candidate for NASA's planned ASCENDS mission. Our technique uses two pulsed laser transmitters allowing simultaneous measurement of a C02 absorption line in the 1570 nm band, 02 extinction in the Oxygen A-band and surface height and backscatter. The lidar measures the energy and time of flight of the laser echoes reflected from the atmosphere and surface. The lasers are stepped in wavelength across the C02 line and an 02 line region during the measurement. The receiver uses a telescope and photon counting detectors, and measures the background light and energies of the laser echoes from the surface along with scattering from any aerosols in the path. The gas extinction and column densities for the C02 and 02 gases are estimated from the ratio of the on- and off- line signals via the DIAL technique. Time gating is used to isolate the laser echo signals from the surface, and to reject laser photons scattered in the atmosphere. We have developed an airborne lidar to demonstrate the C02 measurement from the NASA Glenn Lear 25 aircraft. The airborne lidar steps the pulsed laser's wavelength across a selected C02 line with 20 steps per scan. The line scan rate is 450 Hz and laser pulse widths are I usec. The time resolved laser backscatter is collected by a 20 cm telescope, detected by a photomultiplier and is recorded by a photon counting system. We made initial airborne measurements on flights during October and December 2008. Laser backscatter and absorption measurements were made over a variety of land and water surfaces and through thin and broken clouds. Atmospheric C02 column measurements using the 1571.4, 1572.02 and 1572.33 nm C02 lines. Two flights were made above the DOE SGP ARM site at altitudes from 3-8 km. These nights were coordinated with DOE investigators who Hew an in-situ C02 sensor on a Cessna aircraft under the path. The increasing C02 line absorptions with

  1. Pulsed Airborne Lidar Measurements of Atmospheric CO2 Column Absorption and Line Shapes from 3-13 km Altitudes

    NASA Technical Reports Server (NTRS)

    Abshire, James; Riris, Haris; Allan, Graham; Weaver, Clark; Mao, Jianping; Sun, Xiaoli; Hasselbrack, William

    2010-01-01

    US Department of Energy's (DOE) SGP ARM site at altitudes from 3-8 km. These flights were coordinated with DOE investigators who flew an in-situ CO2 sensor on a Cessna aircraft under the path. The increasing CO2 line absorptions with altitudes were evident and comparison with in-situ measurements showed agreements to 6 ppm. In spring 2009 we improved the aircraft's nadir window and during July and August we made 9 additional 2 hour long flights and measured the atmospheric CO2 absorption and line shapes using the 1572.33 nm CO2 line. Measurements were made at stepped altitudes from 3-13 km over a variety of surface types in Nebraska, Illinois, the SGP ARM site, and near and over the Chesapeake Bay in North Carolina and eastern Virginia. Strong laser signals and clear CO2 line shapes were observed at all altitudes, and some measurements were made through thin clouds. The flights over the ARM site were underflown with in-situ measurements made from the DOE Cessna. Analysis shows that the average signal levels follow predicted values, the altimetry measurements had an uncertainty of about 4 m, and that the average optical line depths follow the number density calculated from in-situ sensor readings. The Oklahoma and east coast flights were coordinated with a LaRC/ITT CO2 lidar on the LaRC UC-12 aircraft, a LaRC in-situ CO2 sensor, and the Oklahoma flights also included a JPL CO2 lidar on a Twin Otter aircraft. More details of the flights, measurements, analysis and scaling to space will be described in the presentation.

  2. Analysis of Pulsed Airborne Lidar Measurements of Atmospheric CO2 Column Absorption from 3-13 km Altitudes

    NASA Technical Reports Server (NTRS)

    Abshire, James B.; Weaver, Clark J.; Riris, Haris; Mao, Jianping; Sun, Xiaoli; Allan, Graham R.; Hasselbrack, William; Browell, Edward V.

    2011-01-01

    We have developed a pulsed lidar technique for measuring the tropospheric CO2 concentrations as a candidate for NASA's ASCENDS space mission [1]. It uses two pulsed laser transmitters allowing simultaneous measurement of a CO2 absorption line in the 1575 nm band, O2 extinction in the Oxygen A-band, surface height and backscatter profile. The lasers are precisely stepped in wavelength across the CO2 line and an O2 line region during the measurement. The direct detection receiver measures the energies of the laser echoes from the surface along with the range profile of scattering in the path. The column densities for the CO2 and O2 gases are estimated from the ratio of the on- and off-line signals via the integrated path differential absorption (IPDA) technique. The time of flight of the laser pulses is used to estimate the height of the scattering surface and to reject laser photons scattered in the atmosphere. We developed an airborne lidar to demonstrate an early version of the CO2 measurement from the NASA Glenn Lear-25 aircraft. The airborne lidar stepped the pulsed laser's wavelength across the selected CO2 line with 20 wavelength steps per scan. The line scan rate is 450 Hz, the laser pulse widths are 1 usec, and laser pulse energy is 24 uJ. The time resolved laser backscatter is collected by a 20 cm telescope, detected by a NIR photomultiplier and is recorded on every other reading by a photon counting system [2]. During August 2009 we made a series of 2.5 hour long flights and measured the atmospheric CO2 absorption and line shapes using the 1572.33 nm CO2 line. Measurements were made at stepped altitudes from 3-13 km over locations in the US, including the SGP ARM site in Oklahoma, central Illinois, north-eastern North Carolina, and over the Chesapeake Bay and the eastern shore of Virginia. Although the received signal energies were weaker than expected for ASCENDS, clear CO2 line shapes were observed at all altitudes, and some measurements were made

  3. Evidence for New Particle Formation Acquired from Equator to Pole and From the Surface to 20 Km Altitude

    NASA Astrophysics Data System (ADS)

    Wilson, J. C.; Saad, M. S.; Meland, B. S.; Axisa, D.

    2016-12-01

    Aerosol particles impact the earth's energy budget by scattering incoming sunlight back to space and by serving as cloud condensation nuclei affecting the optical properties of clouds. Particles also serve as locations for chemical reactions affecting the abundance of ozone and other trace species. Particles formed in the atmosphere affect the size distribution of atmospheric aerosol and contribute to all these processes.Aerosol size distributions in the 4 to 1000 nm diameter range were made on 114 research flights between 1998 and 2013. These measurements were made from -5 N Latitude to 90 N Latitude and from 20 km altitude to the ground. The abundance of ultrafine particles was determined with a Nuclei Mode Aerosol Size Spectrometer (NMASS) which consists of 5 condensation particle counters (CPCs) operated in parallel each having a different supersaturation of the operating fluid and different lower size detection limit. By examining the counts in the CPCs detecting particles larger than 4 nm and 8 nm, it was possible to identify time periods for which particles were observed in the 4 to 8 nm size range. The criterion for identifying the presence of these small particles took counting statistics into account and excluded 99.8% of those events caused by statistical fluctuations. Since new particle formation (NPF) produces vary small particles and these particles are removed rapidly by coagulation with the entire size spectrum of aerosol, the presence of particles in the 4 to 8 nm diameter range is taken to be evidence for recent new particle formation.We present the frequencies with which NPF was observed as a function of latitude and altitude as well as distance from the MERRA tropopause. The abundance of these small particles and the fraction of the total number distribution are also presented as a function of latitude and distance from the tropopause. The spatial resolution of these measurements is approximately 200 m (1 hz) and 2.4 million measurements are

  4. Rayleigh/Raman lidar observations of gravity wave activity from 15 to 70 km altitude over Syowa (69°S, 40°E), the Antarctic

    NASA Astrophysics Data System (ADS)

    Kogure, Masaru; Nakamura, Takuji; Ejiri, Mitsumu K.; Nishiyama, Takanori; Tomikawa, Yoshihiro; Tsutsumi, Masaki; Suzuki, Hidehiko; Tsuda, Takuo T.; Kawahara, Takuya D.; Abo, Makoto

    2017-08-01

    The potential energy of gravity waves (GWs) per unit mass (Ep), at altitudes of 15-70 km, has been examined from temperature profiles obtained by a Rayleigh/Raman lidar at Syowa Station (69°S, 40°E) from May 2011 to October 2013, with the exception of the summer months. The GWs with ground-based wave periods longer than 2 h and vertical wavelengths between 1.8 and 16 km were extracted from the temperature profiles. Ep was larger in winter than in spring and fall, although in 2012, at altitudes below 30 km, Ep was larger in spring than in winter and fall. Ep increased with a mean scale height of 11.3 km. Ep profiles showed a local maximum at an altitude of 20 km and a minimum at 25 km in almost every month, which has not been reported by previous studies observed by radiosondes. The values of Ep in October of 2012 were smaller at 35-60 km and larger at 20-35 km than those in October of 2011 and 2013. This difference in the Ep profile is most probably caused by different seasonal variations of zonal winds. The larger and smaller Ep values seem to be observed both below and above the altitude at which the zonal wind speed reached 0 m s-1. This result suggests that wind filtering of gravity waves with small phase speeds is significantly important in early spring.

  5. Variation of electron and ion density distribution along Earth's magnetic field line deduced from whistler mode (wm) sounding of image/rpi satellite below altitude 5000 km

    NASA Astrophysics Data System (ADS)

    Hazra, Susmita

    This thesis provides a detailed survey and analysis of whistler mode (WM) echoes observed by IMAGE/RPI satellite during the years 2000-2005 below the altitude of 5000 km. Approximately 2500 WM echoes have been observed by IMAGE during this period. This includes mostly specularly reflected whistler mode (SRWM) echoes and ~400 magnetospherically reflected whistler mode (MRWM) echoes. Stanford 2D raytracing simulations and the diffusive equilibrium density model have been applied to 82 cases of MRWM echoes, observed during August-December of the year 2005 below 5000 km to determine electron and ion density measurements along Earth's magnetic field line. These are the first results of electron and ion density measurements from WM sounding covering L-shells ~1.6-4, a wide range of geomagnetic conditions (Kp 0+ to 7), and during solar minima (F10.2~70-120) in the altitude range 90 km to 4000 km. The electron and ion density profiles obtained from this analysis were compared with in situ measurements on IMAGE (passive recording; electron density (Ne)), DMSP (~850 km; Ne and ions), CHAMP (~350 km; Ne), Alouette (~500-2000 km; Ne and ions), ISIS-1, 2 (~600-3500 km; Ne, ions), AE (~130-2000 km; ions) satellites, bottom side sounding from nearby ionosonde stations (Ne), and those by GCPM (Global Core Plasma Model), IRI-2012 (International Reference Ionosphere). Based on this analysis it is found that: (1) Ne shows a decreasing trend from L-shell 1.6 to 4 on both the day and night sides of the plasmasphere up to altitude ~1000 km, which is also confirmed by the GCPM and IRI-2012 model. (2) Above ~2000 km altitude, GCPM underestimates Ne by ~30-90% relative to RPI passive measurements, WM sounding results. (3) Below 1500 km, the Ne is higher at day side than night side MLT (Magnetic Local Time). Above this altitude, significant MLT dependence of electron density is not seen. (4) Ion densities from WM sounding measurements are within 10-35% of those from the Alouette, AE, and

  6. Sildenafil has little influence on cardiovascular hemodynamics or 6-km time trial performance in trained men and women at simulated high altitude.

    PubMed

    Jacobs, Kevin A; Kressler, Jochen; Stoutenberg, Mark; Roos, Bernard A; Friedlander, Anne L

    2011-01-01

    Sildenafil improves maximal exercise capacity at high altitudes (∼4350-5800 m) by reducing pulmonary arterial pressure and enhancing oxygen delivery, but the effects on exercise performance at less severe altitudes are less clear. To determine the effects of sildenafil on cardiovascular hemodynamics (heart rate, stroke volume, and cardiac output), arterial oxygen saturation (SaO2), and 6-km time-trial performance of endurance-trained men and women at a simulated altitude of ∼3900 m. Twenty men and 15 women, endurance-trained, completed one experimental exercise trial (30 min at 55% of altitude-specific capacity +6-km time trial) at sea level (SL) and two trials at simulated high altitude (HA) while breathing hypoxic gas (12.8% FIo2) after ingestion of either placebo or 50 mg sildenafil in double-blind, randomized, and counterbalanced fashion. Maximal exercise capacity and SaO2 were significantly reduced at HA compared to SL (18%-23%), but sildenafil did not significantly improve cardiovascular hemodynamics or time-trial performance in either men or women compared to placebo and only improved SaO2 in women (4%). One male subject (5% of male subjects, 2.8% of all subjects) exhibited a meaningful 36-s improvement in time-trial performance with sildenafil compared to placebo. In this group of endurance trained men and women, sildenafil had very little influence on cardiovascular hemodynamics, SaO2, and 6-km time-trial performance at a simulated altitude of ∼3900 m. It appears that a very small percentage of endurance-trained men and women derive meaningful improvements in aerobic performance from sildenafil at a simulated altitude of ∼3900 m.

  7. An Instrument for the Measurement of Atmospheric CO2 Concentration in the Free Troposphere (0-13 km Altitude)

    NASA Astrophysics Data System (ADS)

    Helten, M.; Smit, H. G. J.

    2003-04-01

    CO_2 is, with water vapor, the most important greenhouse gas in the climate processes (IPCC-Report, 2001). It is used for the study of vertical transport and mean circulation of the atmosphere. But these investigations are based mainly on ground-based measurements over several years. Measurements of vertical profiles were only performed during some field campaigns. Satellite measurements show until now a limited height resolution and accuracy for CO_2, particularly in the troposphere. Furthermore CO_2 measurements would benefit the validation of satellite measurements. Two new satellites with improved features for the measurement of CO_2 (AIRS on EOS PM, IASI on METOP-1) shall be operative in the next years. These data have to be validated. A compact, lightweight CO_2 sensor was tested in the frame of the AFO-2000 programme, which could deliver atmospheric measurements of CO_2 onboard scheduled commercial aircraft in usual operational altitudes of aircraft (0-13 km). The sensor is a commercial solid-state galvanic cell heated to 600^oC, delivering a voltage proportional to the CO_2 partial pressure (Manufacturer: ZIROX). Together with the elctronics unit and a small pump it has a weight of only 350 g and a volume of 600 ccm. A small air stream (50 ml/min) is sucked by the pump through the sensor. Results of laboratory tests of the sensor concerning precision, accuracy, and stability will be presented. Good linearity over a large range between 200 and 1000 ppmV CO_2 and only small deviations of 0.5 ± 1.7 ppmV at levels of 300-400 ppmV CO_2 can be stated. The time response of the sensor is for typical atmospheric concentrations of 300-500 ppmV CO_2 in the range of some seconds. In cooperation with the manufacturer an enhancement of these features is in progress. First results of these measures shall be presented too. A prototype of a sensor usable onboard a Learjet shall be developed this year. Reference: IPPC (=Intergovernmental Panel on Climate Change), Third

  8. Analysis of the nature of excessive cosmic radiation in the area of the Brazilian magnetic anomaly at altitudes 250-500km, from Kosmos-225 satellite data

    NASA Technical Reports Server (NTRS)

    Raychenko, L. V.

    1974-01-01

    Results are presented from a study of the region of anomalous cosmic radiation in the area of the Brazilian magnetic anomaly at the altitudes 250-500 km, using data measurements taken on the Kosmos-225 satellite (14-29 June 1968). The existence of a stable intensity anomaly discovered in the experiments on the second and third Soviet spacecraft-satellites is confirmed. The total vector of the geomagnetic field at different altitudes was compared with isoline maps. An altitude profile of the South Atlantic anomaly of radiation intensity was obtained, using data from the same instrument. The nature of the anomalies in cosmic radiation intensity over the regions of negative magnetic anomalies is discussed.

  9. Cape Kennedy Wind Component Statistics Monthly and Annual Reference Periods for All Flight Azimuths from 0 to 70 KM Altitude

    NASA Technical Reports Server (NTRS)

    Brown, S. C.

    1969-01-01

    Head-, tail-, and cross-wind component speeds for Cape Kennedy are tabulated for all flight azimuths for altitudes from 0 to 70 kilometers by monthly and annual reference periods. Wind speeds are given for 11 selected percentiles ranging from 0.135 percent to 99.865 percent for each reference period.

  10. Temperature characteristics at altitudes of 5-80 km with a self-calibrated Rayleigh-rotational Raman lidar: A summer case study

    NASA Astrophysics Data System (ADS)

    Li, Yajuan; Lin, Xin; Yang, Yong; Xia, Yuan; Xiong, Jun; Song, Shalei; Liu, Linmei; Chen, Zhenwei; Cheng, Xuewu; Li, Faquan

    2017-02-01

    Temperature profiles at altitudes of 5-80 km are obtained with a self-calibrated Rayleigh-rotational Raman lidar over Wuhan, China (30.5°N, 114.5°E). By using the synchronous Rayleigh lidar temperature, rotational Raman temperature in the lower atmosphere could be calibrated and retrieved, which is free of other instruments (like local radiosondes). The results are comparable to the radiosonde calibration method. Based on the self-calibration approach, one-night (August 4-5, 2014) lidar temperature profiles are presented with radiosondes, NRLMSISE-00 model and TIMED/SABER data. Some interesting temperature characteristics have been present for studies of waves propagating from near ground level into the mesosphere. Temperature perturbations are found to increase exponentially with a scale height of 10 km. The wavy structure shows minimal perturbations ('nodes') at some altitudes of 39, 52, 64 and 73 km. Dominant wavelengths and temperature variations are also analyzed at different time and altitudes. By comparison of the temperature and associate perturbations from the tropopause up to the stratopause, different amplitudes, phase fronts and vertical wavelengths are discovered as well. These discoveries indicate that some waves may originate in the lower atmosphere and propagate upward with decreasing static stability.

  11. Sildenafil does not improve steady state cardiovascular hemodynamics, peak power, or 15-km time trial cycling performance at simulated moderate or high altitudes in men and women.

    PubMed

    Kressler, Jochen; Stoutenberg, Mark; Roos, Bernard A; Friedlander, Anne L; Perry, Arlette C; Signorile, Joseph F; Jacobs, Kevin A

    2011-12-01

    Sildenafil improves oxygen delivery and maximal exercise capacity at very high altitudes (≥ 4,350 m), but it is unknown whether sildenafil improves these variables and longer-duration exercise performance at moderate and high altitudes where competitions are more common. The purpose of this study was to determine the effects of sildenafil on cardiovascular hemodynamics, arterial oxygen saturation (SaO(2)), peak exercise capacity (W (peak)), and 15-km time trial performance in endurance-trained subjects at simulated moderate (MA; ~2,100 m, 16.2% F(I)O(2)) and high (HA; ~3,900 m, 12.8% F(I)O(2)) altitudes. Eleven men and ten women completed two HA W (peak) trials after ingesting placebo or 50 mg sildenafil. Subjects then completed four exercise trials (30 min at 55% of altitude-specific W (peak) + 15-km time trial) at MA and HA after ingesting placebo or 50 mg sildenafil. All trials were performed in randomized, counterbalanced, and double-blind fashion. Sildenafil had little influence on cardiovascular hemodynamics at MA or HA, but did result in higher SaO(2) values (+3%, p < 0.05) compared to placebo during steady state and time trial exercise at HA. W (peak) at HA was 19% lower than SL (p < 0.001) and was not significantly affected by sildenafil. Similarly, the significantly slower time trial performance at MA (28.1 ± 0.5 min, p = 0.016) and HA (30.3 ± 0.6 min, p < 0.001) compared to SL (27.5 ± 0.6 min) was unaffected by sildenafil. We conclude that sildenafil is unlikely to exert beneficial effects at altitudes <4,000 m for a majority of the population.

  12. Estimation of precipitable water vapour using kinematic GNSS precise point positioning over an altitude range of 1 km

    NASA Astrophysics Data System (ADS)

    Webb, S. R.; Penna, N. T.; Clarke, P. J.; Webster, S.; Martin, I.

    2013-12-01

    The estimation of total precipitable water vapour (PWV) using kinematic GNSS has been investigated since around 2001, aiming to extend the use of static ground-based GNSS, from which PWV estimates are now operationally assimilated into numerical weather prediction models. To date, kinematic GNSS PWV studies suggest a PWV measurement agreement with radiosondes of 2-3 mm, almost commensurate with static GNSS measurement accuracy, but only shipborne experiments have so far been carried out. As a first step towards extending such sea level-based studies to platforms that operate at a range of altitudes, such as airplanes or land based vehicles, the kinematic GNSS estimation of PWV over an exactly repeated trajectory is considered. A data set was collected from a GNSS receiver and antenna mounted on a carriage of the Snowdon Mountain Railway, UK, which continually ascends and descends through 950 m of vertical relief. Static GNSS reference receivers were installed at the top and bottom of the altitude profile, and derived zenith wet delay (ZWD) was interpolated to the altitude of the train to provide reference values together with profile estimates from the 100 m resolution runs of the Met Office's Unified Model. We demonstrate similar GNSS accuracies as obtained from previous shipborne studies, namely a double difference relative kinematic GNSS ZWD accuracy within 14 mm, and a kinematic GNSS precise point positioning ZWD accuracy within 15 mm. The latter is a more typical airborne PWV estimation scenario i.e. without the reliance on ground-based GNSS reference stations. We show that the kinematic GPS-only precise point positioning ZWD estimation is enhanced by also incorporating GLONASS observations.

  13. Polar/Tide Observations of Field Aligned O(+) Flows at 5000 km Altitude over the Auroral Regions in Comparison to UVI Auroral Images

    NASA Technical Reports Server (NTRS)

    Stevenson, Benjamin Adam; Craven, Paul D.; Chandler, Michael O.; Moore, Thomas E.; Giles, Barbara L.; Parks, G. K.; Pollock, Craig J.

    1999-01-01

    Measurements of thermal O(+) ion parameters from the Thermal Ion Dynamics Experiment (TIDE) on POLAR obtained near 5000 km altitude are compared with auroral images from the Ultra Violet Imager (UVI), for southern perigee passes. Ion parameters, including parallel velocity, density, and flux are combined with simultaneous auroral images to investigate relationships between their properties and the structure and brightness of the auroral forms. Results indicate field aligned upflowing O(+) ions over bright auroral regions and downward flows over dark regions. These and other relationships will be presented for several POLAR passes when both ion measurements and auroral images are observed under favorable conditions for comparison.

  14. Relationships between stratospheric clear air turbulence and synoptic meteorological parameters over the western United States between 12-20 km altitude

    NASA Technical Reports Server (NTRS)

    Scoggins, J. R.; Clark, T. L.; Possiel, N. C.

    1975-01-01

    Procedures for forecasting clear air turbulence in the stratosphere over the western United States from rawinsonde data are described and results presented. Approaches taken to relate meteorological parameters to regions of turbulence and nonturbulence encountered by the XB-70 during 46 flights at altitudes between 12-20 km include: empirical probabilities, discriminant function analysis, and mountainwave theory. Results from these techniques were combined into a procedure to forecast regions of clear air turbulence with an accuracy of 70-80 percent. A computer program was developed to provide an objective forecast directly from the rawinsonde sounding data.

  15. Diagnostics of magnetospheric electron density and irregularities at altitudes <5000 km using whistler and Z mode echoes from radio sounding on the IMAGE satellite

    NASA Astrophysics Data System (ADS)

    Sonwalkar, V. S.; Carpenter, D. L.; Bell, T. F.; Spasojević, M.; Inan, U. S.; Li, J.; Chen, X.; Venkatasubramanian, A.; Harikumar, J.; Benson, R. F.; Taylor, W. W. L.; Reinisch, B. W.

    2004-11-01

    When the Radio Plasma Imager (RPI) on the IMAGE satellite operates in the inner plasmasphere and at moderate to low altitudes over the polar regions, pulses emitted at the low end of its 3-kHz to 3-MHz sounding frequency range can propagate in the whistler mode and/or in the Z mode. During soundings with both 25.6-ms pulses and 3.2-ms pulses, whistler mode echoes have been observed in (1) "discrete," lightning whistler-like forms and (2) diffuse, widely time spread forms suggestive of mode coupling at the boundaries of density irregularities. Discrete echoes have been observed at altitudes less than ≈5000 km both inside the plasmasphere and over the auroral and polar regions, being most common inside the plasmasphere. Diffuse echoes have also been observed at altitudes less than 5000 km, being most common poleward of the plasmasphere. Either discrete or diffuse echoes or both have been detected during one or more soundings on at least half of all IMAGE orbits. In regions poleward of the plasmasphere, diffuse Z mode echoes of a kind reported by Carpenter et al. (2003) were found to accompany both discrete and diffuse whistler mode echoes 90% of the time and were also present during 90% of the soundings when no whistler mode echoes were detected. It is proposed that the observed discrete whistler mode echoes are a consequence of RPI signal reflections at the bottom side of the ionosphere and that diffuse whistler mode echoes are a result of scattering of RPI signals by geomagnetic field-aligned electron density irregularities located within 2000 km earthward of the satellite and in directions close to that of the field line passing through IMAGE. Diffuse Z mode echoes are believed to be due to scattering of RPI signals from electron density irregularities within 3000 km of the satellite, particularly those in the generally cross-B direction. Consistent with previous works, our results indicate that the magnetosphere at high latitudes is highly structured, with

  16. Correcting Mars Global Surveyor Thermal Emission Spectrometer (MGS-TES) High Altitude (40 - 65 km) Temperature Retrievals for Instrumental Correlated Noise and Biases

    NASA Astrophysics Data System (ADS)

    McConnochie, T. H.; Smith, M. D.

    2011-12-01

    Mars Global Surveyor Thermal Emission Spectrometer (MGS-TES) nadir-soundings have been used to derive atmospheric temperatures up to roughly 40 km [Conrath et al., JGR 105 2000, Smith et al., JGR 106, 2001], and MGS-TES limb soundings have been used to extend the atmospheric temperature data set to > 60 km in altitude [Smith et al., JGR 106, 2001]. The ~40 - ~65 km altitude range probed by the MGS-TES limb sounding is particularly important for capturing key dynamical features such as the warm winter polar mesosphere [e.g., Smith et al., JGR 106, 2001; McCleese et al., Nature Geoscience 1, 2008], and the response of thermal tides to dust opacity [e.g. Wilson and Hamilton, J. Atmos. Sci. 53, 1996]. Thus accurate and precise temperature profiles at these altitudes are particularly important for constraining global circulation models. They are also critical for interpreting observations of mesospheric condensate aerosols [e.g., Määttänen et al., Icarus 209, 2010; McConnochie et al., Icarus 210, 2010)]. We have indentified correlated noise components in the MGS-TES limb sounding radiances that propagate into very large uncertainties in the retrieved temperatures. We have also identified a slowly varying radiance bias in the limb sounding radiances. Note that the nadir-sounding-based MGS-TES atmospheric temperatures currently available from the Planetary Data System are not affected by either of these issues. These two issues affect the existing MGS-TES limb sounding temperature data set are as follows: Considering, for example, the 1.5 Pascal pressure level (which typically falls between 50 and 60 km altitude), correlated-noise induced standard errors for individual limb-sounding temperature retrievals were 3 - 5 K in Mars Year 24, rising to 5 - 15 K in Mars Year 25 and 10 - 15 K in Mars Year 26 and 27. The radiance bias, although consistent on ~10-sol time scales, is highly variable over the course of the MGS-TES mission. It results in temperatures (at the 1

  17. Effect of the Ionospheric Parameter Variations at Altitudes of 80-350 km on Diurnal Dynamics of the ULF Magnetic Field Spectra at Midlatitudes

    NASA Astrophysics Data System (ADS)

    Ermakova, E. N.; Kotik, D. S.; Pershin, A. V.; Pilipenko, V. A.; Shiokawa, K.

    2017-05-01

    We study the causes of sporadic and long-term variations in the polarization spectrum of the ultralow-frequency (ULF) magnetic background noise at midlatitudes. Data records of low-frequency horizontal magnetic components at the Novaya Zhizn midlatitude observatory of the Radiophysical Research Institute (56°N, 45.74°E) and the Japanese station Moshiri (44.37°N, 142.27°E) were used. Ionosonde data from the sites located in Russia (Vasilsursk station) and in Japan (Wakkanai station) were also analyzed. The effect of the sporadic Es layers on the frequency spectrum of noise polarization was detected. It is shown that the appearance of quite intense sporadic Es layers with the cutoff frequencies f0Es > 3-5 MHz can significantly alter the polarization spectrum parameters, which is due to variations in the optical depth and Q factor of the sub-ionospheric Alfvén resonator (sub-IAR) formed by the valley between the E and F regions. Numerical simulation of the polarization parameters of the background noise using the IRI-2012 model corrected by the ionosonde data confirmed that the Es layer about 5 km thick, with the cutoff frequencies f0Es > 3-5 MHz, may lead to a sharp decrease in the boundary frequency fb between the frequency ranges of the left- and right-hand polarized noise, or even to a complete disappearance of the sub-IAR manifestation in the polarization parameter spectrum. Numerical calculations have also revealed the impact of the altitude position of the Es layer on the Q factor of the sub-IAR. The effect of variations in the altitude and cutoff frequency of the F-layer maximum, as well as the electron density at the altitudes of the E layer and the valley, on the features of the diurnal dynamics of the ULF noise polarization spectra is discussed.

  18. Global circulation of the Earth's atmosphere at altitudes from 0 to 135 Km simulated with the ARM model. Consideration of the solar activity contribution

    NASA Astrophysics Data System (ADS)

    Krivolutsky, A. A.; Cherepanova, L. A.; Dement'eva, A. V.; Repnev, A. I.; Klyuchnikova, A. V.

    2015-11-01

    The results of simulations of the global circulation and temperature regime in the altitude range from the lower tropospheric layers to 135 km are presented. They were obtained with the Atmospheric Research Model (ARM), an advanced modification of a version of the Cologne Middle Atmosphere Model (COMMA). The ARM is characterized by higher spatial resolution and better parameterizations of the radiation sources and heat sinks. At the lower boundary of the model, wavy sources of perturbations, which are caused by internal gravity waves and planetary waves, are specified. The results of the modeling of the global temperature and wind fields for the mean solar activity level are presented, and their changes, which are caused by variations of the UV-radiation fluxes in the solar activity cycle and by solar proton flares, are also considered.

  19. Three-micron extinction of the Titan haze in the 250-700 km altitude range: Possible evidence of a particle-aging process

    NASA Astrophysics Data System (ADS)

    Courtin, Régis; Kim, Sang Joon; Bar-Nun, Akiva

    2015-01-01

    Context. The chemical nature of the Titan haze is poorly understood. The investigation carried out by the Cassini-Huygens suite of instruments is bringing new insights into this question. Aims: This work aims at deriving the vertical variation of the spectral structure of the 3.3-3.4 μm absorption feature of the Titan haze from Cassini VIMS solar occultation data recorded between 250 and 700 km altitude. Methods: We computed the transmittance of Titan's atmosphere using a spherical shell model and a radiative transfer code including the influence of CH4, CH3D, and C2H6, as well as the effects of absorption and scattering by the haze particles. We derived the haze extinction from a comparison of the synthetic spectra with the VIMS solar occultation spectra. Results: We find a marked change in the relative amplitudes of the 3.33 and 3.38 μm features, which are characteristic of aromatic (double C=C chains or rings) or aliphatic (single C-C chains) structural groups, respectively. The pseudo-ratio of aromatics to aliphatics (uncorrected for the absolute band strengths) varies from 3.3 ± 1.9 at 580-700 km to 0.9 ± 0.1 at 350-450 km, and is 0.5 ± 0.1 around 250 km. The structural change from the aromatic to the aliphatic type between 580 and 480 km appears to correspond to a spontaneous aging of the particles - a transition between unannealed and hardened particles - while the further decrease of the pseudo-ratio of aromatics to aliphatics below 480 km may be related to the coating of the core particles by condensates such as heavy alkanes. VIMS transmission spectra data are only 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/573/A21

  20. Observations of a Breakdown of a Mountain Wave Near 84 km Altitude Over Cerro Pachon Chile from the Andes Lidar Observatory

    NASA Astrophysics Data System (ADS)

    Hecht, J. H.; Gelinas, L. J.; Rudy, R. J.; Walterscheid, R. L.; Taylor, M. J.; Pautet, P. D.; Fritts, D. C.; Smith, S. M.; Franke, S. J.; Mlynczak, M. G.

    2015-12-01

    Mountain waves are produced by flow over orography. They propagate almost vertically, and are characterized by nearly zero velocity phase speed. The altitude to which they typically propagate is not well documented. They are thought to mainly dissipate by absorption in a critical layer although large-amplitude wave breakdown is also thought to occur. There have been almost no direct observations of the breakdown of mountain waves in the upper mesosphere and lower thermosphere. The region over Cerro Pachon Chile (a 2715 meter mountain in the Andes where large astronomical telescopes are located) is especially favorable to the production of mountain waves. In 2009 Smith and colleagues reported on the first observations of such waves propagating into the mesopause region (85 to 95 km) from El Leoncito Argentina, where waves over Cerro Pachon could be seen using airglow observations. The Aerospace Corporation's Nightglow Imager (ANI) is located at the Andes Lidar Observatory near the crest of Cerro Pachon. ANI observes nighttime OH emission (near 1.6 microns) every 2 seconds over an approximate 73 degree field of view. ANI had previously been used to the breakdown of Kelvin-Helmholtz instability features not associated with a specific gravity wave. Here we present OH airglow observations, originating near 84 km, from 22 UT to 3 UT on 8/9 July 2012 that show the breakdown of a mountain wave into instability features that subsequently dissipate into turbulence. These multi-hour observations provide the most detailed images to date of the breakdown of a mountain wave. The causes for, and the results of, the breakdown of this mountain wave are discussed.

  1. Measured effect of VLF transmitters on the inner radiation belt and deduction of the equatorial thermal plasma density at altitudes between 2500 and 4000 km

    NASA Astrophysics Data System (ADS)

    Sauvaud, Jean-Andre; Maggiolo, R.; Parrot, Michel; Berthelier, Jean-Jacques; Gamble, R. J.; Rodger, C. J.

    The radiation belts as measured at low altitudes (700 km) with the DEMETER satellite show discrete large scale energy structures caused by the interaction of electrons with VLF waves. An energy-L dispersed structure due to the interaction of electrons with the powerfull NWC transmitter at 19.8 kHz is seen at all longitudes at L values between 1.4 and 1.8 when the station is in the local night and when the transmitter is on. At a fixed L value, the energy of the resonnating electron varies with the thermal plasma density in the equatorial plane. This density changes with seasons, magnetic activity and UV solar flux. We compare the experimental results with experimental data and try to disentangle these various effects on the equatorial thermal plasma density between 2500 and 4000 km. Two other structures are briefly presented and discussed: A structure with superposed multiple energy bands measured West of America inside the inner radiation belt (L=1.15-1.35) with the electron energy spectra at a given location showing up to 10 peaks in the energy range from 70 keV to 1 MeV, and a structure with up to 12 energy peaks between 200 kev and 2.5 MeV measured west of South Africa at L Value of about 2.7. For this last structures the multiple electron energy peaks are separated by the same energy at a given location. This is tentatively interpreted as indicating that these structures are due to the high orders resonnance of electrons with whistler waves.

  2. The HEX experiment: Determination of the neutral wind field from 120 to 185 km altitude near a stable premidnight auroral arc by triangulating the drift of rocket-deployed chemical trails

    NASA Astrophysics Data System (ADS)

    Wescott, E. M.; Stenbaek-Nielsen, H.; Conde, M.; Larsen, Miguel; Lummerzheim, Dirk

    2006-09-01

    On 25 March 2003, Horizontal E-Region Experiment (HEX) released trimethyl aluminum trails from two rockets launched northward from Poker Flat Research Range near Fairbanks to map the vertical wind field near a stable premidnight auroral arc system. They deployed three trails of trimethyl aluminum chemical "puffs," whose subsequent motion traced the prevailing wind field. This motion was determined using triangulation from four ground observation sites. Position and speed accuracies were estimated to be ˜1 km and a few meters per second, respectively. The first rocket followed a novel flat trajectory; it released a nearly horizontal trail of length 200 km, at an average altitude of ˜145 km. The second rocket was launched 19 min later and released two trails between 125 and 175 km altitude along a conventional steep trajectory. All puffs between 130 and 175 km altitude drifted geomagnetic westward, almost exactly parallel to the aurora. From prior observations and modeling, we had expected to observe convective upwelling near the arcs. We did not; vertical winds were essentially downward throughout the horizontal trail, with speeds between 0 and 20 m s-1. Although an abatement of downward flow was observed ˜40 km equatorward of the arcs, these data alone do not establish a causal relationship between the abatement and the arcs. Vertical speeds of ≤20 m s-1 are relatively modest. However, because the observed wind field would entrain air parcels in flow parallel to the arc system, even vertical speeds around 15 m s-1 could displace individual air parcels by several scale heights if they occurred all along the arcs.

  3. Storm-time changes of geomagnetic field at MAGSAT altitudes (325-550 Km) and their comparison with changes at ground locations

    NASA Technical Reports Server (NTRS)

    Parada, N. D. J. (Principal Investigator); Kane, R. P.; Trivedi, N. B.

    1983-01-01

    The values of H, X, Y, Z at MAGSAT altitudes were first expressed as residuals delta H, delta X, delta Y, delta Z after subtracting the model HMD, XMD, YMD, ZMC. The storm-time variations of H showed that delta H (Dusk) was larger (negative) than delta H (Dawn) and occurred earlier, indicating a sort of hysteresis effect. Effects at MAGSAT altitudes were roughly the same (10% accuracy) as at ground, indicating that these effects were mostly of magnetospheric origin. The delta Y component also showed large storm-time changes. The latitudinal distribution of storm-time delta H showed north-south asymmetries varying in nature as the storm progressed. It seems that the central plane of the storm-time magnetospheric ring current undergoes latitudinal meanderings during the course of the storm.

  4. Venus Altitude Cycling Balloon

    NASA Astrophysics Data System (ADS)

    de Jong, M. L.

    2015-04-01

    A novel balloon concept is demonstrated that uses mechanical compression as altitude control mechanism to sustain long duration balloon probe flight in the cloud level region of Venus’ atmosphere between 45 and 58 km altitude.

  5. Aircraft measurements made during the spring maximum of ozone over Hawaii: Peroxides, CO, O3, NOy, condensation nuclei, selected hydrocarbons, halocarbons, and alkyl nitrates between 0.5 and 9 km altitude

    NASA Astrophysics Data System (ADS)

    Ridley, B. A.; Atlas, E. L.; Walega, J. G.; Kok, G. L.; Staffelbach, T. A.; Greenberg, J. P.; Grahek, F. E.; Hess, P. G.; Montzka, D. D.

    1997-08-01

    Between April 22 and May 11, 1992, ten flights of the University of Wyoming King Air were made during the maximum in tropospheric ozone over the central North Pacific Ocean in conjunction with the spring intensive of the second Mauna Loa Observatory Photochemistry Experiment. During the first week of flights, an episode of remarkably large total reactive nitrogen, NOy (˜2 ppbv) persisted in the 5-9 km altitude region for 3-4 days. Backtrajectory calculations combined with the trace gas and aerosol measurements confirm that its source was due primarily to export from northern latitude continental surface regions. The total amount of odd nitrogen transported over Hawaii during this event was estimated to be 1-2% of the annual emissions from subsonic aircraft or from stratospheric input. Throughout the measurement program layers of elevated O3, NOy, condensation nuclei (CN), and other species were frequently found between the onset of the marine boundary layer temperature inversion and 4-5 km altitude. Structure and strong gradients within these layers contribute to the daily variations seen at the 3.4 km elevation of the Mauna Loa Observatory during the nighttime downslope flow. The dryness of these low-altitude layers and the calculated air mass trajectories indicate that export from northern latitudes occurred mainly with subsidence to the Hawaii region rather than from transit just above the boundary layer inversion. There was no evidence of recent stratospheric input to the altitude region sampled below 9 km. However, the observations cannot distinguish whether O3 input from the stratosphere occurred earlier in the air mass histories at higher latitudes. Fine vertical scale anticorrelations between CN and O3 or NOy were also often observed particularly in the last week of the program when NOy mixing ratios were more typical of the remote troposphere. These features are attributed to new particle formation near the tops of cloud convection episodes and they

  6. A New Analysis of the Spectra Obtained by the Venera Missions in the Venusian Atmosphere. I. The Analysis of the Data Received from the Venera-11 Probe at Altitudes Below 37 km in the 0.44 0.66 µm Wavelength Range

    NASA Astrophysics Data System (ADS)

    Maiorov, B. S.; Ignat'ev, N. I.; Moroz, V. I.; Zasova, L. V.; Moshkin, B. E.; Khatuntsev, I. V.; Ekonomov, A. P.

    2005-07-01

    The processes of the solar radiation extinction in deep layers of the Venus atmosphere in a wavelength range from 0.44 to 0.66 µm have been considered. The spectra of the solar radiation scattered in the atmosphere of Venus at various altitudes above the planetary surface measured by the Venera-11 entry probe in December 1978 are used as observational data. The problem of the data analysis is solved by selecting an atmospheric model; the discrete-ordinate method is applied in calculations. For the altitude interval from 2 10 km to 36 km, the altitude and spectral dependencies of the volume coefficient of true absorption have been obtained. At altitudes of 3 19 km, the spectral dependence is close to the wavelength dependence of the absorption cross section of S3 molecules, whence it follows that the mixing ratio of this sulfur allotrope increases with altitude from 0.03 to 0.1 ppbv.

  7. Geophysical Inversion of Thermospheric Wind Observations by a Multistatic Network of Imaging Fabry-Perot Spectrometers Across Alaska, to Produce 2-Dimensional Maps of Three-Component Wind Vectors at 250 km Altitude.

    NASA Astrophysics Data System (ADS)

    Elliott, J.; Conde, M.

    2016-12-01

    Near-simultaneous measurements of line of sight (LOS) wind speed at 250 km altitude are collected from a network of three Scanning Doppler Imagers (SDIs) distributed across Alaska. Each instrument views the sky down to 70 degrees zenith angle, corresponding to a geographic region roughly 1000 km in diameter. Because there is considerable overlap of the three fields of view, it is possible to invert the line-of-sight component measurements to produce extended two-dimensional maps of the three-component vector wind field. Existing algorithms for this inversion employ either bistatic triangulation or multistatic basis function fitting. Bistatic triangulation analysis resolves finer structure in the actual thermosphere wind field at 250km altitude than basis functions can capture, but is sensitive to noise, artifacting, and is only feasible over limited geographic regions where the bistatic geometry is favorable. We have therefore developed a self tuned geophysical inversion technique using gradient and curvature penalties, to resolve the finest possible structure over the widest possible geographic region. L1,L2 regularization in combination with L1,L2 normalization is explored, along with variance-based cost additions to the objective functions involved. A Moore-Penrose Truncated Singular Value Decomposition (TSVD) provides a frequency independent pseudo-inversion technique. Synthetic wind fields are generated, with added Gaussian noise. Simple analytic functions (sines , hyperbolic tangents, Gaussian distributions, and constants) are used to generate model wind fields with and without large scale wind shears. These fields are sampled into their single line-of-sight components, as would be observed by our actual instruments, and analysis is then performed of the algorithm's ability to reconstruct from this the original (known) 3-component vector wind fields. . Finally we reconstruct wind fields using real data from our Alaskan SDI network and compare it to other data

  8. Conception of Gas and Aerosol Pollution Monitoring of the Earth's Atmosphere (for Altitudes more than 30 km) on Board the International Space Station

    NASA Astrophysics Data System (ADS)

    Morozhenko, O. V.; Shavrina, A. V.; Veles', O. A.

    Approximate model calculations support the idea, according to which the main role in the weakening of the ozone layer power is played by the aerosol pollution of the upper layers in the Earth's atmosphere and freons play a secondary role. For the tasks of exact modelling of the processes which create and destroy ozone and for monitoring of greenhouse gases and ecology of the atmosphere, a conception of experiments on board the Ukrainian module of the International Space Station was proposed. They will provide the possibility to receive information about global changes in the chemical composition of the atmosphere, spectral values of complex refractive index and sizes of the stratospheric aerosol, as well as about the vertical structure of gas and aerosol components of the atmosphere and the vertical temperature profile. Two device complexes are proposed to be mounted, one of them (two Fourier spectrometers for the spectral range 1.5-11μm and a spectropolarimeter for 200-400nm) will be targeted to nadir, and the second (two Fourier spectrometers for the spectral range 1.5-11μm) will observe the spectrum of solar radiation weakened by the Earth's atmosphere at various (with a step of 1-2km) over the Earth's surface.

  9. Ground-based neutral gas environment simulation related to material degradation phenomena in the orbital altitudes of 200-500 km

    NASA Astrophysics Data System (ADS)

    Tagawa, Masahito; Yokota, Kumiko; Oyabu, Takashi; Ohira, Junki; Watanabe, Daiki; Yamasaki, Yuki

    The exterior surface of the spacecraft was covered by thermal control materials that mainly made of polymeric materials such as polyimide or fluorinated ethylenepropylene (FEP). It has been widely known that materials in low Earth orbit (LEO) are subjected to severe degradation caused by various space environmental factors. There are many environmental factors in space, however, atomic oxygen (AO) is one of the major concerns on the material degradation in LEO. The reaction mechanism of AO with materials has been studied by ground-based experiments using laser-detonation hyperthermal beam source, which enables to accelerate the electrically neutral AO up to 8 km/s (orbital velocity of spacecraft). Besides the AO-induced material degradation of hydrocarbons, it has been suspected that the chemically inert heavy molecules, such as N2, have influenced material erosions. In this presentation, effects of Ar collision (simulating the collision energy of N2 in space), sample temperature and vacuum ultraviolet exposures on the AO-induced material erosion were studied. Not only the mass-loss effect, but also the difference in surface chemistry by AO or Ar bombardment will also be presented.

  10. Magnetization reversal phenomena in (Cr0.70Ti0.30)5S6

    NASA Astrophysics Data System (ADS)

    Hashimoto, Satoshi; Matsuda, Yuji; Sato, Tetsuya; Anzai, Shuichiro

    2005-12-01

    Magnetization reversal phenomena (MRP) along magnetic order-order transitions have recently been reported on impurity-doped magnetic systems. Because imperfect long-range magnetic order exists in these systems, it is expected that a systematic investigation of MRP will give physical information on thermomagnetic processes of magnetic systems in the range from the micro- to nanoscales. As a typical order-order transition (a state doubly modulated by helical and canting orders to a collinear ferrimagnetic state) has been known to occur on Cr5S6 at a transition temperature Tt, we investigate the magnetizations of (Cr0.70Ti0.30)5S6 on heating and cooling runs in various magnetic fields. At 20Oe, the field-cooled magnetization just below the Curie temperature has a positive sign; the sign turns negative below the compensation temperature TCM (first step) and finally returns to positive below Tt (second step). The first-step MRP observed in this system is explained by the potential barriers resulting from anisotropy energy when the preferred direction of collinear ferrimagnetic moment reverses. The proposed mechanism for second-step MRP is the pinning effect caused by the impurity atoms (Ti) in the helical long-range-order chains. Comparing other examples of MRPs, we discuss the roles of local impurity centers in the thermomagnetic process in magnetic order-order transitions.

  11. Visualization of Bi3+ off-centering in the average cubic structure of (Ba0.70Bi0.30)(Ti0.70Fe0.30)O3 at the electron density level

    NASA Astrophysics Data System (ADS)

    Singh, Anar; Moriyoshi, Chikako; Kuroiwa, Yoshihiro; Pandey, Dhananjai

    2013-09-01

    We present here evidence for the off-centering of Bi3+ symmetrically distributed along the six ⟨100⟩ directions of a pseudocubic composition (Ba0.70Bi0.30)(Ti0.70Fe0.30)O3 at the electron density distribution level. We also calculate the strength of covalent bonding between the oxygen (O2-) anions with A-site (Ba2+/Bi2+) and B-site (Ti4+/Fe3+) cations, which provides evidence for the stabilization of average cubic symmetry. We believe that Bi3+ positional disorder may be ubiquitous in all the lead free piezoceramic solid solutions of the type (Ba1-xBix)(Ti1-xMex)O3, where Me = Fe3+, Sc3+, Al3+, (Mg1/2Ti1/2)3+, and (Zn1/2Ti1/2)3+.

  12. Controllable cracking behavior in Si/Si0.70Ge0.30/Si heterostructure by tuning the H+ implantation energy

    NASA Astrophysics Data System (ADS)

    Chen, Da; Zhang, Nan; Wang, Bei; Xu, Anli; Li, Ya; Yang, Siwei; Wang, Gang; Guo, Qinglei

    2017-08-01

    Controllable cracking behaviors are realized in Si with a buried B doped Si0.70Ge0.30 interlayer by tuning the H+ projected ranges using the traditional H implantation technique. When the projected range is shallower (deeper) than the depth of the buried Si0.70Ge0.30 layer, cracking occurs at the interface between the top Si layer (bottom handle Si wafer) and the Si0.70Ge0.30 interlayer, thus resulting in the formation of continuous sharp crack confined at the Si0.70Ge0.30/Si interfaces. For the case that the H-ion projected range is located at the B-doped Si0.70Ge0.30 buried interlayer, continuous cracking is observed along the interlayer, which is similar to the conventional ion-cut method. We attribute these controlled cracking behaviors to the B doped Si0.70Ge0.30 interlayer, which holds a large amount of B impurities and compressive strain, and H ions can be trapped and confined at the interfaces or within the interlayer (depended on projected ranges) to facilitate the formation of cracks.

  13. Venus balloons at low altitudes

    NASA Astrophysics Data System (ADS)

    Nishimura, J.; Hinada, M.; Yajima, N.; Fujii, M.

    1994-02-01

    The Venus balloons are one of the most important vehicles to explore the dynamics and composition of Venusian atmosphere and several feasibility studies have been reported. We here propose the balloons at low altitude of 10 to 20 km floating below the cloud in the Venus atmosphere, which will make it possible to perform the study of the Venus atmosphere at low altitude together with a direct observation of the Venus surface. The atmospheric pressure is 20 to 40 atm. at this altitude, and the temperature is as high as 300 C to 400 C. The balloons proposed here are of the spherical shape of super pressure type filled by the Helium gas. The balloons are made of thin Ti alloy or reinforced by CFRP, and have capabilities to carry the payloads of weights of several kg. This type of the balloon has several merits on the weight considerations over the normal inflatable balloons with gas containers and its inlet systems.

  14. Venus balloons at low altitudes.

    NASA Astrophysics Data System (ADS)

    Nishimura, J.; Hinada, M.; Yajima, N.; Fujii, M.

    1994-02-01

    The Venus balloons are one of the most important vehicles to explore the dynamics and composition of Venusian atmosphere. The authors here propose the balloons at low altitude of 10 to 20 km floating below the cloud in the Venus atmosphere, which will make it possible to perform the study of the Venus atmosphere at low altitude together with a direct observation of the Venus surface. The atmospheric pressure is 20 to 40 atm at this altitude, and the temperature is as high as 300°C to 400°C. The balloons proposed here are of the spherical shape of super pressure type filled by the Helium gas. The balloons are made of thin Ti alloy or reinforced by CFRP, and have capabilities to carry the payloads of weights of several kg.

  15. 40Km Into Lebanon,

    DTIC Science & Technology

    1987-07-01

    answer to the difficulties in Palestine, London organized a study of the problem under Lord Peel , a for- mer Secretary of State for India, who in 1937...issued the report of the Commission bearing his name. As Peel saw it, the only solution was to partition Palestine between the two communities. The...minority suggestions. The majority 22 40Km into Lebanon report recommended partition with an economic union, much as Peel had proposed in 1937. A

  16. Radiation measurements and doses at SST altitudes

    NASA Technical Reports Server (NTRS)

    Foelsche, T.

    1972-01-01

    Radiation components and dose equivalents due to galactic and solar cosmic rays in the high atmosphere, especially at SST altitudes, are presented. The dose equivalent rate for the flight personnel flying 500 hours per year in cruise altitudes of 60,000-65,000 feet (18-19.5 km) in high magnetic latitudes is about 0.75-1.0 rem per year averaged over the solar cycle, or about 15-20 percent of the maximum permissible dose rate.

  17. Self-irradiation effect on thermal conductivity of Zr0.70Pu0.25Cm0.05N solid solution

    NASA Astrophysics Data System (ADS)

    Nishi, Tsuyoshi; Hayashi, Hirokazu; Sato, Takumi; Takano, Masahide

    2017-04-01

    This study evaluated the dependence of the thermal conductivity of Zr0.70Pu0.25Cm0.05N on storage time and temperature. The authors prepared sintered samples of Zr0.70Pu0.25Cm0.05N solid solution and measured thermal diffusivity at storage times of 0, 24, 72, 144, 240, 408, 552, 816, 1,680, and 2064 h, from which it was determined that the thermal conductivity decreased exponentially with increasing storage time. This result suggests that the decrease of the thermal conductivity could be attributed to the accumulation of lattice defects from self-irradiation. To confirm the thermal recovery behavior of Zr0.70Pu0.25Cm0.05N under annealing, thermal diffusivity was also measured just after annealing. The thermal conductivity of Zr0.70Pu0.25Cm0.05N was determined to be larger than that of Zr0.58Pu0.21Cm0.21N but smaller than that of Zr0.80Pu0.10Cm0.10N.

  18. High Altitude Launch for a Practical SSTO

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Denis, Vincent; Lyons, Valerie (Technical Monitor)

    2003-01-01

    Existing engineering materials allow the construction of towers to heights of many kilometers. Orbital launch from a high altitude has significant advantages over sea-level launch due to the reduced atmospheric pressure, resulting in lower atmospheric drag on the vehicle and allowing higher rocket engine performance. High-altitude launch sites are particularly advantageous for single-stage to orbit (SSTO) vehicles, where the payload is typically 2% of the initial launch mass. An earlier paper enumerated some of the advantages of high altitude launch of SSTO vehicles. In this paper, we calculate launch trajectories for a candidate SSTO vehicle, and calculate the advantage of launch at launch altitudes 5 to 25 kilometer altitudes above sea level. The performance increase can be directly translated into increased payload capability to orbit, ranging from 5 to 20% increase in the mass to orbit. For a candidate vehicle with an initial payload fraction of 2% of gross lift-off weight, this corresponds to 31% increase in payload (for 5-km launch altitude) to 122% additional payload (for 25-km launch altitude).

  19. High Altitude Launch for a Practical SSTO

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Denis, Vincent

    2003-01-01

    Existing engineering materials allow the construction of towers to heights of many kilometers. Orbital launch from a high altitude has significant advantages over sea-level launch due to the reduced atmospheric pressure, resulting in lower atmospheric drag on the vehicle and allowing higher rocket engine performance. high-altitude launch sites are particularly advantageous for single-stage to orbit (SSTO) vehicles, where the payload is typically 2% of the initial launch mass. An earlier paper enumerated some of the advantages of high altitude launch of SSTO vehicles. In this paper, we calculate launch trajectories for a candidate SSTO vehicle, and calculate the advantage of launch at launch altitudes 5 to 25 kilometer altitudes above sea level. The performance increase can be directly translated in to increased payload capability to orbit, ranging from 5 to 20% increase in the mass to orbit. For a candidate vehicle with an initial payload fraction of 2% of gross lift-off weight, this corresponds to 31 % increase in payload (for 5-km launch altitude) to 122% additional payload (for 25-km launch altitude).

  20. Gravity Waves Near 300 km Over the Polar Caps

    NASA Technical Reports Server (NTRS)

    Johnson, F. S.; Hanson, W. B.; Hodges, R. R.; Coley, W. R.; Carignan, G. R.; Spencer, N. W.

    1995-01-01

    Distinctive wave forms in the distributions of vertical velocity and temperature of both neutral particles and ions are frequently observed from Dynamics Explorer 2 at altitudes above 250 km over the polar caps. These are interpreted as being due to internal gravity waves propagating in the neutral atmosphere. The disturbances characterized by vertical velocity perturbations of the order of 100 m/s and horizontal wave lengths along the satellite path of about 500 km. They often extend across the entire polar cap. The associated temperature perturbations indicate that the horizontal phase progression is from the nightside to the dayside. Vertical displacements are inferred to be of the order of 10 km and the periods to be of the order of 10(exp 3) s. The waves must propagate in the neutral atmosphere, but they usually are most clearly recognizable in the observations of ion vertical velocity and ion temperature. By combining the neutral pressure calculated from the observed neutral concentration and temperature with the vertical component of the neutral velocity, an upward energy flux of the order of 0.04 erg/sq cm-s at 250 km has been calculated, which is about equal to the maximum total solar ultraviolet heat input above that altitude. Upward energy fluxes calculated from observations on orbital passes at altitudes from 250 to 560 km indicate relatively little attenuation with altitude.

  1. Ears and Altitude

    MedlinePlus

    ... ENTCareers Marketplace Find an ENT Doctor Near You Ears and Altitude Ears and Altitude Patient Health Information ... uncomfortable feeling of fullness or pressure. Why do ears pop? Normally, swallowing causes a little click or ...

  2. Magnetic and magnetotransport properties of nanocrystalline Ag 0.85Fe 0.15 and Ag 0.70Fe 0.30 alloys prepared by mechanical alloying

    NASA Astrophysics Data System (ADS)

    Gómez, J. A.; Xia, S. K.; Passamani, E. C.; Giordanengo, B.; Baggio-Saitovitch, E. M.

    2001-01-01

    The magnetic and magnetotransport properties of nanocrystalline Ag 0.85Fe 0.15 and Ag 0.70Fe 0.30 alloys have been studied by Mössbauer spectroscopy, magnetization and resistivity measurements. The samples were prepared by mechanical alloying of Fe and Ag powders in a high-energy ball mill. Mössbauer spectroscopy and magnetic measurements of the final milled samples indicate the presence of single-domain 'Fe' particles. The magnetoresistance values, at 4.2 K and for a magnetic field of 8 T, are 2.5% and 5.7% for samples Ag 0.85Fe 0.15 and Ag 0.70Fe 0.30, respectively. The magnetoresistance behavior indicates the cluster-glass-like features in both the final milled samples.

  3. Separation Characteristics of the MK-82 AIR when Released from the F-111 Aircraft at Mach Numbers from 0.70 to 1.25

    DTIC Science & Technology

    1976-05-01

    WHEN RELEASED FROM THE F-111 AIRCRAFT AT MACH NUMBERS FROM 0.70 TO 1.25 PROPULSION WIND TUNNEL FACILITY ARNOLD ENGINEERING DEVELOPMENT CENTER- AIR...PREFACE The work reported herein was conducted by the Arnold Engineering Development Center (AEDC), Air Force Systems Command (AFSC), at the request...U. S. Government drawings specifications, or other data are used for any purpose other than a definitely related Government procurement operation

  4. High altitude decelerator systems

    NASA Technical Reports Server (NTRS)

    Silbert, Mendel N.; Moltedo, A. David; Gilbertson, Gaylord S.

    1989-01-01

    High Altitude Decelerator Systems are used to provide a stable descending platform when deployed from a sounding rocket at altitudes greater than 40 kilometers allowing a scientific mission to be conducted in a specific altitude region. The High Altitude Decelerator is designed to provide a highly stable, high drag area system packed in a minimum volume to deploy successfully from a sounding rocket. Deployment altitudes greater than 100 kilometers have been successfully demonstrated at dynamic pressures as low as 0.004 pounds per square foot.

  5. High-Altitude Medicine.

    PubMed

    Johnson, Nicholas J; Luks, Andrew M

    2016-03-01

    Individuals may seek the advice of medical providers when considering travel to high altitude. This article provides a basic framework for counseling and evaluating such patients. After defining "high altitude" and describing the key environmental features at higher elevations, the physiologic changes that occur at high altitude and how these changes are experienced by the traveler are discussed. Clinical features and strategies for prevention and treatment of the main forms of acute altitude illness are outlined, and frameworks for approaching the common clinical scenarios that may be encountered regarding high-altitude travelers are provided. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Athletes at High Altitude

    PubMed Central

    Khodaee, Morteza; Grothe, Heather L.; Seyfert, Jonathan H.; VanBaak, Karin

    2016-01-01

    Context: Athletes at different skill levels perform strenuous physical activity at high altitude for a variety of reasons. Multiple team and endurance events are held at high altitude and may place athletes at increased risk for developing acute high altitude illness (AHAI). Training at high altitude has been a routine part of preparation for some of the high level athletes for a long time. There is a general belief that altitude training improves athletic performance for competitive and recreational athletes. Evidence Acquisition: A review of relevant publications between 1980 and 2015 was completed using PubMed and Google Scholar. Study Design: Clinical review. Level of Evidence: Level 3. Results: AHAI is a relatively uncommon and potentially serious condition among travelers to altitudes above 2500 m. The broad term AHAI includes several syndromes such as acute mountain sickness (AMS), high altitude pulmonary edema (HAPE), and high altitude cerebral edema (HACE). Athletes may be at higher risk for developing AHAI due to faster ascent and more vigorous exertion compared with nonathletes. Evidence regarding the effects of altitude training on athletic performance is weak. The natural live high, train low altitude training strategy may provide the best protocol for enhancing endurance performance in elite and subelite athletes. High altitude sports are generally safe for recreational athletes, but they should be aware of their individual risks. Conclusion: Individualized and appropriate acclimatization is an essential component of injury and illness prevention. PMID:26863894

  7. Local fluctuations of ozone from 16 km to 45 km deduced from in situ vertical ozone profile

    NASA Technical Reports Server (NTRS)

    Moreau, G.; Robert, C.

    1994-01-01

    A vertical ozone profile obtained by an in situ ozone sonde from 16 km to 45 km, has allowed to observe local ozone concentration variations. These variations can be observed, thanks to a fast measurement system based on a UV absorption KrF excimer laser beam in a multipass cell. Ozone standard deviation versus altitude calculated from the mean is derived. Ozone variations or fluctuations are correlated with the different dynamic zones of the stratosphere.

  8. Photoluminescence study of magnetic spin clusters and their temperature evolution in Cd0.70Mn0.30Te spin-glass compound

    NASA Astrophysics Data System (ADS)

    Gnatenko, Yu. P.; Bukivskij, P. M.

    2012-11-01

    We have investigated microscopic magnetic spin states (MMSSs) ("loose spins, finite superparamagnetic, `locked' and infinite clusters") both above and below the freezing temperature in Cd0.70Mn0.30Te spin glass (SG). We used the localized exciton magnetic polarons, which we observed in the photoluminescence spectra, as a probe. This makes it possible to estimate the MMSS's relative concentrations and to study their temperature evolution and thus to elucidate one of the most important issues in this field of research. Furthermore, the findings described here open new prospects for further studies of spin freezing in the different SGs, especially, in dilute magnetic semiconductors.

  9. Recovery of train-of-four ratio to 0.70 and 0.90 is delayed in type 2 diabetes with vecuronium-induced neuromuscular block.

    PubMed

    Nitahara, Keiichi; Sugi, Yasuyuki; Shigematsu, Kenji; Haraga, Isamu; Abe, Shintaro; Higa, Kazuo

    2013-02-01

    The recovery profile of train-of-four ratio to more than 0.70 in patients with diabetes mellitus has not been well investigated. Our primary objective was to evaluate the spontaneous recovery profile of neuromuscular block by vecuronium until train-of-four ratio more than 0.90 in patients with type 2 diabetes mellitus compared with controls, using first dorsal interosseous electromyography. Single-centre prospective case-control study. The operating theatres of Fukuoka University Hospital. Fourteen adults with type 2 diabetes mellitus (diabetes mellitus group) and 14 control patients (control group) were included in this study. Evoked responses to train-of-four stimuli were measured by electromyography at the first dorsal interosseous muscle. General anaesthesia was induced with propofol, fentanyl and remifentanil. Vecuronium (0.1  mg kg) was administered to all patients. Anaesthesia was maintained with propofol, fentanyl and remifentanil. The neuromuscular block was assessed until spontaneous recovery to train-of-four ratio more than 0.90. Recovery times to train-of-four ratio 0.70 and 0.90. Recovery times to train-of-four ratio 0.70 and 0.90 were significantly longer in the diabetes mellitus group than the control group (P = 0.041 and P = 0.027, respectively). The time from train-of-four ratio 0.25 to 0.90 was also significantly longer in the diabetes mellitus group than the control group (P = 0.029). In five of 14 patients in the diabetes mellitus group, the time from train-of-four ratio 0.25 to 0.90 was longer than 60  min, which is longer than the duration of action of neostigmine. The time from train-of-four ratio 0.25 to 0.90 was longer than 60  min in only one of 14 in the control group. Recovery times to train-of-four ratio 0.70 and 0.90 were delayed in patients with type 2 diabetes mellitus. Neuromuscular block by vecuronium should be carefully monitored in patients with type 2 diabetes mellitus until recovery of train-of-four ratio to

  10. Fulminant high altitude blindness.

    PubMed

    Mashkovskiy, Evgeny; Szawarski, Piotr; Ryzhkov, Pavel; Goslar, Tomaz; Mrak, Irena

    2016-06-01

    Prolonged altitude exposure even with acclimatization continues to present a physiological challenge to all organ systems including the central nervous system. We describe a case of a 41-year-old Caucasian female climber who suffered severe visual loss that was due to possible optic nerve pathology occurring during a high altitude expedition in the Himalayas. This case is atypical of classic high altitude cerebral oedema and highlights yet another danger of prolonged sojourn at extreme altitudes. © International Society of Travel Medicine, 2016. All rights reserved. Published by Oxford University Press. For permissions, please e-mail: journals.permissions@oup.com.

  11. Low X-ray luminosity galaxy clusters - II. Optical properties and morphological content at 0.18 < z < 0.70

    NASA Astrophysics Data System (ADS)

    Nilo Castellón, José Luis; Alonso, M. Victoria; García Lambas, Diego; O'Mill, Ana Laura; Valotto, Carlos; Carrasco, Eleazar R.; Cuevas, Héctor; Ramírez, Amelia

    2014-01-01

    This is the second of a series of papers on low X-ray luminosity galaxy clusters, in which we present the r', g' and i' photometry obtained with Gemini Multi-Object Spectrograph IMAGE at Gemini North and South telescopes for seven systems in the redshift range of 0.18 to 0.70. Optical magnitudes, colours and morphological parameters, namely, concentration index, ellipticity and visual morphological classification, are also given. At lower redshifts, the presence of a well-defined red cluster sequence extending by more than 4 mag showed that these intermediate-mass clusters had reached a relaxed stage. This was confirmed by the small fraction of blue galaxy members observed in the central regions of ˜0.75 Mpc. In contrast, galaxy clusters at higher redshifts had a less important red cluster sequence. We also found that the galaxy radial density profiles in these clusters were well fitted by a single power law. At 0.18 < z < 0.70, we observed an increasing fraction of blue galaxies and a decreasing fraction of lenticulars, with the early-type fraction remaining almost constant. Overall, the results of these intermediate-mass clusters are in agreement with those for high-mass clusters.

  12. Time-resolved photoluminescence spectroscopy of localized exciton magnetic polarons in Cd{sub 0.70}Mn{sub 0.30}Te spin glass compound

    SciTech Connect

    Gnatenko, Yu. P. Bukivskij, P. M.; Piryatinski, Yu. P.

    2014-04-07

    We have investigated dynamics of different localized exciton magnetic polarons (LEMPs) in Cd{sub 0.70}Mn{sub 0.30}Te spin glass (SG) compound below the freezing temperature T{sub f} in the crystal regions, where various microscopic magnetic spin states (MMSSs), namely, “loose” spins, finite, and infinite clusters, are formed. It was shown that there is a broad distribution of the LEMPs lifetimes. The presence of the long-lived LEMPs is caused by the admixture of the optically active bright exciton states to the dark exciton states, i.e., the “brightening” of the dark LEMPs which exist along with the bright LEMPs. The lifetimes of the dark LEMPs correspond to hundreds of nanoseconds. It was found that the time decay of photoluminescence band intensity is approximated by the sum of two functions: a single exponential function and the Kohlrausch–Williams–Watts stretched exponential function. The stretched exponential function describes the recombination processes of the LEMPs formed in the crystal regions of the finite clusters as well as the infinite cluster. This reflects the appearance of spatially heterogeneous dynamics in Cd{sub 0.70}Mn{sub 0.30}Te SG compound below T{sub f} which is due to the disorder in the spin distribution caused by the formation of different MMSSs.

  13. Acceleration of barium ions near 8000 km above an aurora

    NASA Technical Reports Server (NTRS)

    Stenbaek-Nielsen, H. C.; Hallinan, T. J.; Wescott, E. M.; Foeppl, H.

    1984-01-01

    A barium shaped charge, named Limerick, was released from a rocket launched from Poker Flat Research Range, Alaska, on March 30, 1982, at 1033 UT. The release took place in a small auroral breakup. The jet of ionized barium reached an altitude of 8100 km 14.5 min after release, indicating that there were no parallel electric fields below this altitude. At 8100 km the jet appeared to stop. Analysis shows that the barium at this altitude was effectively removed from the tip. It is concluded that the barium was actually accelerated upward, resulting in a large decrease in the line-of-sight density and hence the optical intensity. The parallel electric potential in the acceleration region must have been greater than 1 kV over an altitude interval of less than 200 km. The acceleration region, although presumably auroral in origin, did not seem to be related to individual auroral structures, but appeared to be a large-scale horizontal structure. The perpendicular electric field below, as deduced from the drift of the barium, was temporally and spatially very uniform and showed no variation related to individual auroral structures passing through.

  14. High Altitude Plasma Instrument (HAPI) data analysis

    NASA Technical Reports Server (NTRS)

    Burch, J. L.

    1994-01-01

    The objectives of the Dynamics Explorer mission are to investigate the coupling of energy, mass, and momentum among the earth's magnetosphere, ionosphere, and upper atmosphere. At launch, on August 3, 1981, DE-1 was placed into an elliptical polar orbit having an apogee of 23,130 km to allow global auroral imaging and crossings of auroral field lines at altitudes of several thousand kilometers. At the same time DE-2 was placed into a polar orbit, coplanar with that of DE-1 but with a perigee altitude low enough (309 km) for neutral measurements and an apogee altitude of 1012 km. The DE-1 High Altitude Plasma Instrument (HAPI) provided data on low and medium energy electrons and ions from August 13, 1981 until December 1, 1981, when a high-voltage failure occured. Analysis of HAPI data for the time period of this contract has produced new results on the source mechanisms for electron conical distributions, particle acceleration phenomena in auroral acceleration regions, Birkeland currents throughout the nightside auroral regions, the source region for auroral kilometric radiation (AKR), and plasma injection phenomena in the polar cusp.

  15. 157km BOTDA with pulse coding and image processing

    NASA Astrophysics Data System (ADS)

    Qian, Xianyang; Wang, Zinan; Wang, Song; Xue, Naitian; Sun, Wei; Zhang, Li; Zhang, Bin; Rao, Yunjiang

    2016-05-01

    A repeater-less Brillouin optical time-domain analyzer (BOTDA) with 157.68km sensing range is demonstrated, using the combination of random fiber laser Raman pumping and low-noise laser-diode-Raman pumping. With optical pulse coding (OPC) and Non Local Means (NLM) image processing, temperature sensing with +/-0.70°C uncertainty and 8m spatial resolution is experimentally demonstrated. The image processing approach has been proved to be compatible with OPC, and it further increases the figure-of-merit (FoM) of the system by 57%.

  16. Wind tunnel investigation of a Centaur standard shroud compartment vent from Mach number of 0.70 to 1.96

    NASA Technical Reports Server (NTRS)

    Johns, A. L.; Jones, M. L.

    1975-01-01

    An experimental investigation was conducted in the Lewis Research Center 8- by 6-foot supersonic wind tunnel to determine the vent discharge coefficient for the Centaur standard shroud/liquid hydrogen tank compartment vent. The test was conducted from Mach 0.70 to 1.96 with the vent mounted in a flat plate. Full scale simulated flight hardware, such as the vent, corrugations, aft field joint ring and ice bag clip was used. Air was discharged from a plenum chamber, located on the tunnel sidewall behind the plate, through five 6.35 cm diameter vent orifices into the free stream. Boundary layer thickeners, analytically predicted displacement thickness for the vehicle nominal flight trajectory could be simulated over the Mach number range. The highest vent discharge coefficient for any given Mach number and vent pressure ratio generally occurred at the maximum displacement thickness.

  17. Heteroepitaxial growth of In0.30Ga0.70As high-electron mobility transistor on 200 mm silicon substrate using metamorphic graded buffer

    NASA Astrophysics Data System (ADS)

    Kohen, David; Nguyen, Xuan Sang; Yadav, Sachin; Kumar, Annie; Made, Riko I.; Heidelberger, Christopher; Gong, Xiao; Lee, Kwang Hong; Lee, Kenneth Eng Kian; Yeo, Yee Chia; Yoon, Soon Fatt; Fitzgerald, Eugene A.

    2016-08-01

    We report on the growth of an In0.30Ga0.70As channel high-electron mobility transistor (HEMT) on a 200 mm silicon wafer by metal organic vapor phase epitaxy. By using a 3 μm thick buffer comprising a Ge layer, a GaAs layer and an InAlAs compositionally graded strain relaxing buffer, we achieve threading dislocation density of (1.0 ± 0.3) × 107 cm-2 with a surface roughness of 10 nm RMS. No phase separation was observed during the InAlAs compositionally graded buffer layer growth. 1.4 μm long channel length transistors are fabricated from the wafer with IDS of 70 μA/μm and gm of above 60 μS/μm, demonstrating the high quality of the grown materials.

  18. A Raman scattering study of the antiferroelectric phase transition in (Sr0.70Ca0.30)TiO3

    NASA Astrophysics Data System (ADS)

    Mishra, Sanjay Kumar; Ranjan, Rajeev; Pandey, Dhananjai; Ouillon, R.; Pinan-Lucarre, J.-P.; Ranson, P.; Pruzan, Ph.

    2001-09-01

    The Raman scattering measurements on ceramic pellets of Sr0.70Ca0.30TiO3 (SCT 30) have been carried out as a function of temperature from 290 K to 8 K. It is shown that below (236+/-5 K), two additional lines appear around 79 and 128 cm-1. Further, there is enhancement in the intensity of the modes near 170 and 541 cm-1 below (236+/-5 K). The temperature at which these changes occur in the Raman spectra of SCT 30 correlates very well with the temperature at which the antiferroelectric superlattice reflections appear in the x-ray diffraction patterns. We propose that the additional modes are due to q≠0 phonons that have become Raman active due to the folding of the corresponding special points into the zone center below the cell-doubling antiferroelectric phase-transition temperature.

  19. KM3NeT

    SciTech Connect

    Jong, M. de; Collaboration: KM3NeT Collaboration

    2015-07-15

    KM3NeT is a large research infrastructure, that will consist of a network of deep-sea neutrino telescopes in the Mediterranean Sea. The main objective of KM3NeT is the discovery and subsequent observation of high-energy neutrino sources in the Universe. A further physics perspective is the measurement of the mass hierarchy of neutrinos. A corresponding study, ORCA, is ongoing within KM3NeT. A cost effective technology for (very) large water Cherenkov detectors has been developed based on a new generation of low price 3-inch photo-multiplier tubes. Following the successful deployment and operation of two prototypes, the construction of the KM3NeT research infrastructure has started. The prospects of the different phases of the implementation of KM3NeT are summarised.

  20. 45-km horizontal path optical link demonstration

    NASA Astrophysics Data System (ADS)

    Biswas, Abhijit; Wright, Malcolm W.; Sanii, Babak; Page, Norman A.

    2001-06-01

    Observations made during a mountain-top-to-mountain-top horizontal optical link demonstration are described. The optical link spans a range of 46 Km at an average altitude of 2 Km above sea level. A multibeam beacon comprised of eight laser beams emerging from four multimode fiber coupled lasers (780 nm) is launched through a 0.6 m diameter telescope located at the JPL Table Mountain Facility (TMF) in Wrightwood, California. The multibeam beacon is received at Strawberry Peak located in the San Bernardino Mountains of California. The NASA, JPL developed optical communications demonstrator (OCD) receives the beacon, senses the atmospheric turbulence induced motion and using an upgraded fine steering loop actively points a communications laser beam (852 nm, 400 Mbps on-off key modulated, PN7 pseudo random bit sequence) to TMF. The eight-beam beacon allowed a four-fold reduction in normalized irradiance or scintillation index. This in turn was sufficient to eliminate beacon fades sensed by the OCD and enable performance evaluation of the fine steering loop. The residual tracking error was determined to be +/- 1.1 to +/- 1.7 (mu) rad compared to a model prediction of +/- 3.4 (mu) rad. The best link performance observed showed average bit error rates (BER) of 1E-5 over long durations (30 seconds); however, instantaneous BERs of at least 0.8E-6 over durations of 2 ms were observed. The paper also discusses results pertaining to atmospheric effects, link analysis, and overall performance.

  1. Phase separation and size effects in Pr(0.70)Ba(0.30)MnO(3+δ) perovskite manganites.

    PubMed

    Trukhanov, S V; Trukhanov, A V; Botez, C E; Adair, A H; Szymczak, H; Szymczak, R

    2007-07-04

    The crystal structure and magnetotransport properties of the A-site ionic ordered state in Pr(0.70)Ba(0.30)MnO(3+δ) (δ = 0, 0.025) have been investigated. It is shown that such a state can be formed in complex manganites with cation ratios [Formula: see text] by using a 'two-step' reduction-reoxidization method. The parent A-site ionic disordered Pr(0.70)Ba(0.30)MnO(3+δ) (δ = 0) compound is an orthorhombic (SG = Imma, Z = 4) ferromagnet with Curie temperature T(C)≈173 K and ground-state spontaneous magnetic moment σ(S)∼3.70 µ(B)/f.u. It exhibits two metal-insulator transitions, at T(I)∼128 K and T(II)∼173 K, as well as two peaks of magnetoresistance ∼74% and ∼79% in a field of 50 kOe. The parent A-site ionic disordered Pr(0.70)Ba(0.30)MnO(3+δ) (δ = 0) sample used in our studies has an average grain size [Formula: see text]. Successive annealing of this sample in vacuum P[O(2)]≈10(-4) Pa and then in air at T = 800 °C leads to the destruction of its initial grain structure and to its chemical separation into two phases: (i) oxygen stoichiometric A-site ordered PrBaMn(2)O(6) with a tetragonal (SG = P4/mmm, Z = 2) perovskite-like unit cell and Curie temperature T(C)≈313 K and (ii) oxygen superstoichiometric A-site disordered Pr(0.90)Ba(0.10)MnO(3.05) with an orthorhombic (SG = Pnma, Z = 4) perovskite-like unit cell and Curie temperature T(C)≈133 K. This processed sample has a spontaneous magnetic moment σ(S)∼2.82 µ(B)/f.u. in its ground state, and σ(S)∼0.59 μ(B)/f.u. at T∼300 K. It also exhibits a magnetoresistance of ∼14% at ∼313 K in a field of 50 kOe. This processed sample has a reduced average grain size [Formula: see text] nm. The two magnetic phases, Pr(0.90)Ba(0.10)MnO(3.05) and PrBaMn(2)O(6), are exchange-coupled. For Pr(0.90)Ba(0.10)MnO(3.05) the temperature hysteresis is ∼22 K in a field of 10 Oe and ∼5 K in a field of 1 kOe. The observed magnetic properties are interpreted in terms of chemical

  2. Observation of radio-wave-induced red hydroxyl emission at low altitude in the ionosphere.

    PubMed

    Kagan, L M; Nicolls, M J; Kelley, M C; Carlson, H C; Belikovich, V V; Bakhmet'eva, N V; Komrakov, G P; Trondsen, T S; Donovan, E

    2005-03-11

    We report the discovery of radio-wave-induced red emission of OH Meinel rotation-vibrational bands at 629.79 nm. These are the first measurements of artificial aurora below 100 km. We believe that the 629.79-nm OH emission was due to radio-wave focusing by sporadic ionization clouds near 80-85 km altitude, thus giving a technique to visualize the low-altitude sporadic ionization and providing insight into ionospheric interactions at these low altitudes.

  3. High altitude illness

    PubMed

    Hartman-Ksycińska, Anna; Kluz-Zawadzka, Jolanta; Lewandowski, Bogumił

    High-altitude illness is a result of prolonged high-altitude exposure of unacclimatized individuals. The illness is seen in the form of acute mountain sickness (AMS) which if not treated leads to potentially life-threatening high altitude pulmonary oedema and high-altitude cerebral oedema. Medical problems are caused by hypobaric hypoxia stimulating hypoxia-inducible factor (HIF) release. As a result, the central nervous system, circulation and respiratory system function impairment occurs. The most important factor in AMS treatment is acclimatization, withdrawing further ascent and rest or beginning to descent; oxygen supplementation, and pharmacological intervention, and, if available, a portable hyperbaric chamber. Because of the popularity of high-mountain sports and tourism better education of the population at risk is essential.

  4. Endurance training at altitude.

    PubMed

    Saunders, Philo U; Pyne, David B; Gore, Christopher J

    2009-01-01

    Since the 1968 Olympic Games when the effects of altitude on endurance performance became evident, moderate altitude training ( approximately 2000 to 3000 m) has become popular to improve competition performance both at altitude and sea level. When endurance athletes are exposed acutely to moderate altitude, a number of physiological responses occur that can comprise performance at altitude; these include increased ventilation, increased heart rate, decreased stroke volume, reduced plasma volume, and lower maximal aerobic power ((.)Vo(2max)) by approximately 15% to 20%. Over a period of several weeks, one primary acclimatization response is an increase in the volume of red blood cells and consequently of (.)Vo(2max). Altitudes > approximately 2000 m for >3 weeks and adequate iron stores are required to elicit these responses. However, the primacy of more red blood cells for superior sea-level performance is not clear-cut since the best endurance athletes in the world, from Ethiopia (approximately 2000 to 3000 m), have only marginally elevated hemoglobin concentrations. The substantial reduction in (.)Vo(2max) of athletes at moderate altitude implies that their training should include adequate short-duration (approximately 1 to 2 min), high-intensity efforts with long recoveries to avoid a reduction in race-specific fitness. At the elite level, athlete performance is not dependent solely on (.)Vo(2max), and the "smallest worthwhile change" in performance for improving race results is as little as 0.5%. Consequently, contemporary statistical approaches that utilize the concept of the smallest worthwhile change are likely to be more appropriate than conventional statistical methods when attempting to understand the potential benefits and mechanisms of altitude training.

  5. Altitude and endurance training.

    PubMed

    Rusko, Heikki K; Tikkanen, Heikki O; Peltonen, Juha E

    2004-10-01

    The benefits of living and training at altitude (HiHi) for an improved altitude performance of athletes are clear, but controlled studies for an improved sea-level performance are controversial. The reasons for not having a positive effect of HiHi include: (1) the acclimatization effect may have been insufficient for elite athletes to stimulate an increase in red cell mass/haemoglobin mass because of too low an altitude (< 2000-2200 m) and/or too short an altitude training period (<3-4 weeks); (2) the training effect at altitude may have been compromised due to insufficient training stimuli for enhancing the function of the neuromuscular and cardiovascular systems; and (3) enhanced stress with possible overtraining symptoms and an increased frequency of infections. Moreover, the effects of hypoxia in the brain may influence both training intensity and physiological responses during training at altitude. Thus, interrupting hypoxic exposure by training in normoxia may be a key factor in avoiding or minimizing the noxious effects that are known to occur in chronic hypoxia. When comparing HiHi and HiLo (living high and training low), it is obvious that both can induce a positive acclimatization effect and increase the oxygen transport capacity of blood, at least in 'responders', if certain prerequisites are met. The minimum dose to attain a haematological acclimatization effect is > 12 h a day for at least 3 weeks at an altitude or simulated altitude of 2100-2500 m. Exposure to hypoxia appears to have some positive transfer effects on subsequent training in normoxia during and after HiLo. The increased oxygen transport capacity of blood allows training at higher intensity during and after HiLo in subsequent normoxia, thereby increasing the potential to improve some neuromuscular and cardiovascular determinants of endurance performance. The effects of hypoxic training and intermittent short-term severe hypoxia at rest are not yet clear and they require further study.

  6. High altitude plumes at Mars morning terminator

    NASA Astrophysics Data System (ADS)

    Sanchez-Lavega, A.; Garcia Muñoz, A.; Garcia Melendo, E.; Perez-Hoyos, S.; Gomez Forrellad, J. M.; Pellier, C.; Delcroix, M.; Lopez Valverde, M. A.; González Galindo, F.; Jaeschke, W.; Parker, D.; Phillips, J.; Peach, D.

    2015-10-01

    In March and April 2012 two extremely high altitude plumes were observed at the Martian terminator reaching 200 -250 km or more above the surface[1]. They were located at about 195o West longitude and 45o South latitude (at Terra Cimmeria) and extended ˜500 -1,000 km in both North-South and East- West, and lasted for about 10 days. Both plumes exhibited day-to-day variability, and were seen at the morning terminator but not at the evening limb. Another large plume was captured on Hubble Space Telescope images in May 1997 at 99º West longitude and 3º South latitude, but its altitude cannot be pr ecisely determined.Broad-band photometry was performed of both events in the spectral range 255 nm -1052 nm. Based on the observed properties, we discuss different possible scenarios for the mechanism responsible for the formation of these plumes.

  7. Height and altitude distribution of large volcanoes on Venus

    NASA Technical Reports Server (NTRS)

    Keddie, S. T.; Head, J. W.

    1994-01-01

    Magellan data reveal 156 large volcanoes on Venus (greater than 100 km in diameter) which range in height from 300 m to 5.55 km, with an average height of 1.42 km. On the basis of theory it has been predicted that the development of neutral buoyancy zones (NBZ) on Venus and thus the resulting volcanic deposits are strongly influenced by the altitude-controlled variations in surface pressure. The distribution and height of these large volcanoes as a function of altitude was examined to begin to test these predications. Although large volcanoes are relatively uniformly distributed in altitude, there may be a slight paucity of volcanoes at the lowest elevations and a slight surplus at mid-altitudes. In addition, it is observed that the volcanoes at the highest altitudes tend to be the tallest. The observed distributions at low-mid altitudes is consistent with the prediction of NBZ theory. The high altitude distribution and heights, however, emphasize the necessity of considering other factors, such as tectonic setting, edifice age, magma supply, and thermal gradient, in describing the location and development of large volcanoes on Venus.

  8. Height and altitude distribution of large volcanoes on Venus

    NASA Technical Reports Server (NTRS)

    Keddie, S. T.; Head, J. W.

    1994-01-01

    Magellan data reveal 156 large volcanoes on Venus (greater than 100 km in diameter) which range in height from 300 m to 5.55 km, with an average height of 1.42 km. On the basis of theory it has been predicted that the development of neutral buoyancy zones (NBZ) on Venus and thus the resulting volcanic deposits are strongly influenced by the altitude-controlled variations in surface pressure. The distribution and height of these large volcanoes as a function of altitude was examined to begin to test these predications. Although large volcanoes are relatively uniformly distributed in altitude, there may be a slight paucity of volcanoes at the lowest elevations and a slight surplus at mid-altitudes. In addition, it is observed that the volcanoes at the highest altitudes tend to be the tallest. The observed distributions at low-mid altitudes is consistent with the prediction of NBZ theory. The high altitude distribution and heights, however, emphasize the necessity of considering other factors, such as tectonic setting, edifice age, magma supply, and thermal gradient, in describing the location and development of large volcanoes on Venus.

  9. Environmental dynamics at orbital altitudes

    NASA Technical Reports Server (NTRS)

    Karr, G. R.

    1976-01-01

    The influence of real satellite aerodynamics on the determination of upper atmospheric density was investigated. A method of analysis of satellite drag data is presented which includes the effect of satellite lift and the variation in aerodynamic properties around the orbit. The studies indicate that satellite lift may be responsible for the observed orbit precession rather than a super rotation of the upper atmosphere. The influence of simplifying assumptions concerning the aerodynamics of objects in falling sphere analysis were evaluated and an improved method of analysis was developed. Wind tunnel data was used to develop more accurate drag coefficient relationships for studying altitudes between 80 and 120 Km. The improved drag coefficient relationships revealed a considerable error in previous falling sphere drag interpretation. These data were reanalyzed using the more accurate relationships. Theoretical investigations of the drag coefficient in the very low speed ratio region were also conducted.

  10. CAT altitude avoidance system

    NASA Technical Reports Server (NTRS)

    Gary, B. L. (Inventor)

    1982-01-01

    A method and apparatus are provided for indicating the altitude of the tropopause or of an inversion layer wherein clear air turbulence (CAT) may occur, and the likely severity of any such CAT, includes directing a passive microwave radiometer on the aircraft at different angles with respect to the horizon. The microwave radiation measured at a frequency of about 55 GHz represents the temperature of the air at an ""average'' range of about 3 kilometers, so that the sine of the angle of the radiometer times 3 kilometers equals the approximate altitude of the air whose temperature is measured. A plot of altitude (with respect to the aircraft) versus temperature of the air at that altitude, can indicate when an inversion layer is present and can indicate the altitude of the tropopause or of such an inversion layer. The plot can also indicate the severity of any CAT in an inversion layer. If CAT has been detected in the general area, then the aircraft can be flown at an altitude to avoid the tropopause or inversion layer.

  11. High Altitude Pilgrimage Medicine

    PubMed Central

    2014-01-01

    Abstract Religious pilgrims have been going to high altitude pilgrimages long before trekkers and climbers sojourned in high altitude regions, but the medical literature about high altitude pilgrimage is sparse. Gosainkunda Lake (4300 m) near Kathmandu, Nepal, and Shri Amarnath Yatra (3800 m) in Sri Nagar, Kashmir, India, are the two sites in the Himalayas from where the majority of published reports of high altitude pilgrimage have originated. Almost all travels to high altitude pilgrimages are characterized by very rapid ascents by large congregations, leading to high rates of acute mountain sickness (AMS). In addition, epidemiological studies of pilgrims from Gosainkunda Lake show that some of the important risk factors for AMS in pilgrims are female sex and older age group. Studies based on the Shri Amarnath Yatra pilgrims show that coronary artery disease, complications of diabetes, and peptic ulcer disease are some of the common, important reasons for admission to hospital during the trip. In this review, the studies that have reported these and other relevant findings will be discussed and appropriate suggestions made to improve pilgrims' safety at high altitude. PMID:25330393

  12. Neutral winds above 200Km at high latitudes

    NASA Technical Reports Server (NTRS)

    Meriwether, J. W.; Heppner, J. P.; Stolarik, J. D.; Wescott, E. M.

    1972-01-01

    Motion from multiple chemical releases between 200 and 300 km from 15 rockets launched from 4 high latitude locations are analyzed. The observations in the evening and midnight hours at magnetic altitudes or = 65 deg suggest that in these regions ion drag is the dominant force in driving neutral winds between 200 and 300 km. This conclusion is based on both the agreement between ion and neutral drift directions, and the fact that there are distinct changes in the wind associated with (a) the reversal in east-west ion drift at the Harang discontinuity, and (b) the transition from auroral belt, sunward ion drift and polar cap, anti-solar ion drift.

  13. Geodetic altitude to a triaxial ellipsoidal planet

    NASA Technical Reports Server (NTRS)

    Tang, Charles C. H.

    1988-01-01

    An efficient theoretical model for determining geodetic altitudes with better than millimeter accuracy is proposed, with application to the TOPEX/Poseidon project. The triaxial ellipsoidal subsurface point of a satellite is used as the initial trial solution to achieve an efficient and simple iterative solution. It is found that the second-iteration solution is exact to an accuracy of at least 10 to the -9th km.

  14. Geodetic altitude to a triaxial ellipsoidal planet

    NASA Astrophysics Data System (ADS)

    Tang, Charles C. H.

    1988-09-01

    An efficient theoretical model for determining geodetic altitudes with better than millimeter accuracy is proposed, with application to the TOPEX/Poseidon project. The triaxial ellipsoidal subsurface point of a satellite is used as the initial trial solution to achieve an efficient and simple iterative solution. It is found that the second-iteration solution is exact to an accuracy of at least 10 to the -9th km.

  15. Impact of Target Altitude Restrictions on Laser Performance

    DTIC Science & Technology

    1989-01-01

    frequent. For a given average fluence, however, the fluence per pulse is much larger for induction FELs ( IFELs ), which are pulsed only about one...thousandth as often. Estimates indicate that IFELs could be limited to targets at altitudes of >80 km, but that RF FELs could interact down to 0-20 km...1. If IFELs were unable to irradiate targets below 80 km, their performance would be reduced by a factor of «3 relative to RF FELs; if they were

  16. Altitude Registration of Limb-Scattered Radiation

    NASA Technical Reports Server (NTRS)

    Moy, Leslie; Bhartia, Pawan K.; Jaross, Glen; Loughman, Robert; Kramarova, Natalya; Chen, Zhong; Taha, Ghassan; Chen, Grace; Xu, Philippe

    2017-01-01

    One of the largest constraints to the retrieval of accurate ozone profiles from UV backscatter limb sounding sensors is altitude registration. Two methods, the Rayleigh scattering attitude sensing (RSAS) and absolute radiance residual method (ARRM), are able to determine altitude registration to the accuracy necessary for long-term ozone monitoring. The methods compare model calculations of radiances to measured radiances and are independent of onboard tracking devices. RSAS determines absolute altitude errors, but, because the method is susceptible to aerosol interference, it is limited to latitudes and time periods with minimal aerosol contamination. ARRM, a new technique introduced in this paper, can be applied across all seasons and altitudes. However, it is only appropriate for relative altitude error estimates. The application of RSAS to Limb Profiler (LP) measurements from the Ozone Mapping and Profiler Suite (OMPS) on board the Suomi NPP (SNPP) satellite indicates tangent height (TH) errors greater than 1 km with an absolute accuracy of +/-200 m. Results using ARRM indicate a approx. 300 to 400m intra-orbital TH change varying seasonally +/-100 m, likely due to either errors in the spacecraft pointing or in the geopotential height (GPH) data that we use in our analysis. ARRM shows a change of approx. 200m over 5 years with a relative accuracy (a long-term accuracy) of 100m outside the polar regions.

  17. Altitude registration of limb-scattered radiation

    NASA Astrophysics Data System (ADS)

    Moy, Leslie; Bhartia, Pawan K.; Jaross, Glen; Loughman, Robert; Kramarova, Natalya; Chen, Zhong; Taha, Ghassan; Chen, Grace; Xu, Philippe

    2017-01-01

    One of the largest constraints to the retrieval of accurate ozone profiles from UV backscatter limb sounding sensors is altitude registration. Two methods, the Rayleigh scattering attitude sensing (RSAS) and absolute radiance residual method (ARRM), are able to determine altitude registration to the accuracy necessary for long-term ozone monitoring. The methods compare model calculations of radiances to measured radiances and are independent of onboard tracking devices. RSAS determines absolute altitude errors, but, because the method is susceptible to aerosol interference, it is limited to latitudes and time periods with minimal aerosol contamination. ARRM, a new technique introduced in this paper, can be applied across all seasons and altitudes. However, it is only appropriate for relative altitude error estimates. The application of RSAS to Limb Profiler (LP) measurements from the Ozone Mapping and Profiler Suite (OMPS) on board the Suomi NPP (SNPP) satellite indicates tangent height (TH) errors greater than 1 km with an absolute accuracy of ±200 m. Results using ARRM indicate a ˜ 300 to 400 m intra-orbital TH change varying seasonally ±100 m, likely due to either errors in the spacecraft pointing or in the geopotential height (GPH) data that we use in our analysis. ARRM shows a change of ˜ 200 m over ˜ 5 years with a relative accuracy (a long-term accuracy) of ±100 m outside the polar regions.

  18. Altitude Registration of Limb-Scattered Radiation

    NASA Technical Reports Server (NTRS)

    Moy, Leslie; Bhartia, Pawan K.; Jaross, Glen; Loughman, Robert; Kramarova, Natalya; Chen, Zhong; Taha, Ghassan; Chen, Grace; Xu, Philippe

    2017-01-01

    One of the largest constraints to the retrieval of accurate ozone profiles from UV backscatter limb sounding sensors is altitude registration. Two methods, the Rayleigh scattering attitude sensing (RSAS) and absolute radiance residual method (ARRM), are able to determine altitude registration to the accuracy necessary for long-term ozone monitoring. The methods compare model calculations of radiances to measured radiances and are independent of onboard tracking devices. RSAS determines absolute altitude errors, but, because the method is susceptible to aerosol interference, it is limited to latitudes and time periods with minimal aerosol contamination. ARRM, a new technique introduced in this paper, can be applied across all seasons and altitudes. However, it is only appropriate for relative altitude error estimates. The application of RSAS to Limb Profiler (LP) measurements from the Ozone Mapping and Profiler Suite (OMPS) on board the Suomi NPP (SNPP) satellite indicates tangent height (TH) errors greater than 1 km with an absolute accuracy of +/-200 m. Results using ARRM indicate a approx. 300 to 400m intra-orbital TH change varying seasonally +/-100 m, likely due to either errors in the spacecraft pointing or in the geopotential height (GPH) data that we use in our analysis. ARRM shows a change of approx. 200m over 5 years with a relative accuracy (a long-term accuracy) of 100m outside the polar regions.

  19. Knob manager (KM) operators guide

    SciTech Connect

    1993-10-08

    KM, Knob Manager, is a tool which enables the user to use the SUNDIALS knob box to adjust the settings of the control system. The followings are some features of KM: dynamic knob assignments with the user friendly interface; user-defined gain for individual knob; graphical displays for operating range and status of each process variable is assigned; backup and restore one or multiple process variable; save current settings to a file and recall the settings from that file in future.

  20. Altitude Modulates Concussion Incidence

    PubMed Central

    Smith, David W.; Myer, Gregory D.; Currie, Dustin W.; Comstock, R. Dawn; Clark, Joseph F.; Bailes, Julian E.

    2013-01-01

    Background: Recent research indicates that the volume and/or pressure of intracranial fluid, a physiology affected by one’s altitude (ie, elevation above sea level), may be associated with the likelihood and/or severity of a concussion. The objective was to employ an epidemiological field investigation to evaluate the relationship between altitude and concussion rate in high school sports. Hypothesis: Because of the physiologies that occur during acclimatization, including a decline in intracranial compliance (a “tighter fit”), increased altitude may be related to a reduction in concussion rates in high school athletes. Study Design: Cohort study; Level of evidence, 3. Methods: Data on concussions and athlete exposures (AEs) between 2005-2006 and 2011-2012 were obtained from a large national sample of high schools (National High School Sports-Related Injury Surveillance System [High School RIO]) and were used to calculate total, competition, and practice concussion rates for aggregated sports and for football only. Results: Altitude of participating schools ranged from 7 to 6903 ft (median, 600 ft), and a total of 5936 concussions occurred in 20,618,915 exposures (2.88 per 10,000 AEs). When concussion rates were dichotomized by altitude using the median, elevated altitude was associated with a reduction in concussion rates overall (rate ratio [RR], 1.31; P < .001), in competition (RR, 1.31; P < .001), and in practice (RR, 1.29; P < .001). Specifically, high school sports played at higher altitude demonstrated a 31% reduction (95% confidence interval [CI], 25%-38%) in the incidence of total reported concussions. Likewise, concussion rates at increased altitude were reduced 30% for overall exposures, 27% for competition exposures, and 28% for practice exposures in football players (P < .001). Conclusion: The results of this epidemiological investigation indicate increased physiological responses to altitude may be associated with a reduction in sports

  1. High Altitude Medical Problems

    PubMed Central

    Hultgren, Herbert N.

    1979-01-01

    Increased travel to high altitude areas by mountaineers and nonclimbing tourists has emphasized the clinical problems associated with rapid ascent. Acute mountain sickness affects most sojourners at elevations above 10,000 feet. Symptoms are usually worse on the second or third day after arrival. Gradual ascent, spending one to three days at an intermediate altitude, and the use of acetazolamide (Diamox) will prevent or ameliorate symptoms in most instances. Serious and potentially fatal problems, such as high altitude pulmonary edema or cerebral edema, occur in approximately 0.5 percent to 1.0 percent of visitors to elevations above 10,000 feet—especially with heavy physical exertion on arrival, such as climbing or skiing. Early recognition, high flow oxygen therapy and prompt descent are crucially important in management. Our knowledge of the causes of these and other high altitude problems, such as retinal hemorrhage, systemic edema and pulmonary hypertension, is still incomplete. Even less is known of the effect of high altitudes on medical conditions common at sea level or on the action of commonly used drugs. ImagesFigure 2. PMID:483805

  2. High-altitude medicine

    PubMed Central

    Paralikar, Swapnil J.; Paralikar, Jagdish H.

    2010-01-01

    Sojourns to high altitude have become common for recreation and adventure purposes. In most individuals, gradual ascent to a high altitude leads to a series of adaptive changes in the body, termed as acclimatization. These include changes in the respiratory, cardiovascular, hematologic systems and cellular adaptations that enhance oxygen delivery to the tissues and augment oxygen uptake. Thus there is an increase in pulmonary ventilation, increase in diffusing capacity in the lung, an increase in the cardiac output and increase in the red blood cell count due to an increase in erythropoietin secretion by the kidney, all of which enhance oxygen delivery to the cells. Cellular changes like increase in the number of mitochondria and augmentation of cytochrome oxidase systems take months or years to develop. Too rapid an ascent or inability to acclimatize leads to high-altitude illnesses. These include acute mountain sickness (AMS), high-altitude cerebral edema (HACE) and high-altitude pulmonary edema (HAPE). Acute mountain sickness is self limiting if recognized early. Both HACE and HAPE are life threatening and need to be treated aggressively. The key to treatment of these illnesses is early recognition; administration of supplemental oxygen; and descent if required. Drugs like acetazolamide, dexamethasone, nifedipine may be administered as recommended. PMID:20808661

  3. Microstructural characterisation of near- α titanium alloy Ti-6Al-4Sn-4Zr-0.70Nb-0.50Mo-0.40Si

    NASA Astrophysics Data System (ADS)

    Ramachandra, C.; Singh, A. K.; Sarma, G. M. K.

    1993-06-01

    Microstructural stability in the near-α titanium alloy (alloy 834) containing Ti-6Al-4Sn-4Zr-0.70Nb-0.50Mo-0.40Si (in weight percent), in the β and (α + β) solution-treated and quenched conditions, has been investigated. The β transus for this alloy is approximately 1333 K. Solution treatment in the β phase field at 1353 K followed by quenching in water at room temperature resulted in the formation of α' martensite platelets with high dislocation density and stacking faults. Thin films of β are found to be sandwiched between interface phases, which, in turn, are sandwiched at the interplatelet boundaries of lath martensite. The interface phase is a subject of much controversy in the literature. Solution treatment at 1303 K in the (α + β) phase field followed by quenching in water at room temperature resulted in the near-equiaxed primary α and transformed β. Both the β and (α + β) solution-treated specimens were aged in the temperature range of 873 to 973 K. While aging the —treated specimen at 973 K, (α + β)-treated specimen, even at a lower temperature of 873 K for 24 hours, caused precipitation of suicides predominantly at the interplatelet boundaries of martensite laths. Electron diffraction analysis confirmed them to be hexagonal suicide S2 with a = 0.702 nm and c = 0.368 nm. The above difference in the precipitation could be attributed to the partitioning of a higher amount of β - stabilizing elements as well as silicide-forming elements to the transformed β in the (α + β) solution-treated condition. However, ordering of the α' phase was observed under all of the aging conditions studied. The ordered domains were due to the longer aging times, which cause local increases in the level of the α-stabilizing elements.

  4. Low-Altitude Wind Shear Detection With Doppler Radar

    DTIC Science & Technology

    1987-02-01

    feasibility of using the next generation weather radar ( NEXRAD ) sys- tem to detect low-altitude horizontal wind shear near airports is investi- gated. We...requires that NEXRAD radar coverage havd’> lowest scan of 60 m above the surface in the airport area (within 20 km of the,,airport); the strongest...Availability Codes * Avail ~id/or Di’.t Special LIST OF FIGURES Figure 1. FAA requirements of altitude limits of NEXRAD coverage and resolu- tion in

  5. Description of SHARC: The Strategic High-Altitude Radiance Code.

    DTIC Science & Technology

    1989-08-16

    for Paths from 60 to 300 km altitude in he 2-40 _.m spectral region. It models r-adiation due to NLTE (Non-Local Thermodynamic quilibrium) molecular...2 HIGH-ALTITUDE INFRARED RADIATION CONCEPTS ... ....... 4 2.1 Non-Local Thermodynamic Equilibrium .... ........ 4 2.2 Vibrational Temperature...Non-Local Thermodynamic Equilibrium) populations of higher vibrational states are included in the calculation. The equivalent-width, line-by-line LBL

  6. Estimation of high altitude Martian dust parameters

    NASA Astrophysics Data System (ADS)

    Pabari, Jayesh; Bhalodi, Pinali

    2016-07-01

    Dust devils are known to occur near the Martian surface mostly during the mid of Southern hemisphere summer and they play vital role in deciding background dust opacity in the atmosphere. The second source of high altitude Martian dust could be due to the secondary ejecta caused by impacts on Martian Moons, Phobos and Deimos. Also, the surfaces of the Moons are charged positively due to ultraviolet rays from the Sun and negatively due to space plasma currents. Such surface charging may cause fine grains to be levitated, which can easily escape the Moons. It is expected that the escaping dust form dust rings within the orbits of the Moons and therefore also around the Mars. One more possible source of high altitude Martian dust is interplanetary in nature. Due to continuous supply of the dust from various sources and also due to a kind of feedback mechanism existing between the ring or tori and the sources, the dust rings or tori can sustain over a period of time. Recently, very high altitude dust at about 1000 km has been found by MAVEN mission and it is expected that the dust may be concentrated at about 150 to 500 km. However, it is mystery how dust has reached to such high altitudes. Estimation of dust parameters before-hand is necessary to design an instrument for the detection of high altitude Martian dust from a future orbiter. In this work, we have studied the dust supply rate responsible primarily for the formation of dust ring or tori, the life time of dust particles around the Mars, the dust number density as well as the effect of solar radiation pressure and Martian oblateness on dust dynamics. The results presented in this paper may be useful to space scientists for understanding the scenario and designing an orbiter based instrument to measure the dust surrounding the Mars for solving the mystery. The further work is underway.

  7. Influence of buffer-layer construction and substrate orientation on the electron mobilities in metamorphic In{sup 0.70}Al{sup 0.30}As/In{sup 0.76}Ga{sup 0.24}As/In{sup 0.70}Al{sup 0.30}As structures on GaAs substrates

    SciTech Connect

    Kulbachinskii, V. A.; Oveshnikov, L. N.; Lunin, R. A.; Yuzeeva, N. A.; Galiev, G. B.; Klimov, E. A.; Pushkarev, S. S.; Maltsev, P. P.

    2015-07-15

    The influence of construction of the buffer layer and misorientation of the substrate on the electrical properties of In{sup 0.70}Al{sup 0.30}As/In{sup 0.76}Ga{sup 0.24}As/In{sup 0.70}Al{sup 0.30}As quantum wells on a GaAs substrate is studied. The temperature dependences (in the temperature range of 4.2 K < T < 300 K) and field dependences (in magnetic fields as high as 6 T) of the sample resistances are measured. Anisotropy of the resistances in different crystallographic directions is detected; this anisotropy depends on the substrate orientation and construction of the metamorphic buffer layer. In addition, the Hall effect and the Shubnikov–de Haas effect are studied. The Shubnikov–de Haas effect is used to determine the mobilities of electrons separately in several occupied dimensionally quantized subbands in different crystallographic directions. The calculated anisotropy of mobilities is in agreement with experimental data on the anisotropy of the resistances.

  8. Space Station Freedom altitude strategy

    NASA Technical Reports Server (NTRS)

    Mcdonald, Brian M.; Teplitz, Scott B.

    1990-01-01

    The Space Station Freedom (SSF) altitude strategy provides guidelines and assumptions to determine an altitude profile for Freedom. The process for determining an altitude profile incorporates several factors such as where the Space Shuttle will rendezvous with the SSF, when reboosts must occur, and what atmospheric conditions exist causing decay. The altitude strategy has an influence on all areas of SSF development and mission planning. The altitude strategy directly affects the micro-gravity environment for experiments, propulsion and control system sizing, and Space Shuttle delivery manifests. Indirectly the altitude strategy influences almost every system and operation within the Space Station Program. Evolution of the SSF altitude strategy has been a very dynamic process over the past few years. Each altitude strategy in turn has emphasized a different consideration. Examples include a constant Space Shuttle rendezvous altitude for mission planning simplicity, or constant micro-gravity levels with its inherent emphasis on payloads, or lifetime altitudes to provide a safety buffer to loss of control conditions. Currently a new altitude strategy is in development. This altitude strategy will emphasize Space Shuttle delivery optimization. Since propellant is counted against Space Shuttle payload-to-orbit capacity, lowering the rendezvous altitude will not always increase the net payload-to-orbit, since more propellant would be required for reboost. This altitude strategy will also consider altitude biases to account for Space Shuttle launch slips and an unexpected worsening of atmospheric conditions. Safety concerns will define a lower operational altitude limit, while radiation levels will define upper altitude constraints. The evolution of past and current SSF altitude strategies and the development of a new altitude strategy which focuses on operational issues as opposed to design are discussed.

  9. Statistics and variability of the altitude of elves

    NASA Astrophysics Data System (ADS)

    van der Velde, Oscar A.; Montanyà, Joan

    2016-05-01

    From June 2008 to January 2016 nearly 800 elves have been recorded by a low-light camera in northeastern Spain. Elves occur in this region mainly over the lower topped cold air mass maritime thunderstorms, peaking from November to January. Cloud-to-ground strokes still produce elves when maritime winter storms are carried inland, suggesting that the cold season thunderstorm charge configuration favors strokes with large electromagnetic pulses. Altitudes of 389 elves were determined using optical data combined with a lightning location network. The overall median altitude was 87.1 km, near the typical OH airglow height, but average heights during individual nights ranged between 83 and 93 km. The lower elve nights (~84 km) occurred during slightly elevated geomagnetic conditions (Kp >3-, Ap-index >10). Elve altitude often shifts by several kilometers during the night, apparently in response to changing background conditions in the upper mesosphere.

  10. Seasonal Variability of Storm Top Altitudes in the Tropics and Subtropics Observed by TRMM PR

    NASA Astrophysics Data System (ADS)

    Chen, Fengjiao; Fu, Yunfei; Liu, Peng; Yang, Yuanjian

    2016-03-01

    Seasonal variability of storm top altitudes for convective and stratiform precipitation in the tropics and subtropics are investigated based on measurements of the Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) from 1998 to 2011. Statistically, the spatial distribution of mean convective storm top altitudes shows a large variation between land and ocean, while the stratiform storm tops exhibit insignificant land-ocean differences. Seasonal variances of tropical convective and stratiform storm top altitudes are small, with their means are approximately at 5 km (6 km) and 5.5 km (6 km) over the ocean (land) in each season. In the subtropics, the difference of the storm top altitudes between summer and winter reaches ~ 4 km and ~ 2 km for convective and stratiform precipitation, respectively. The zonal mean storm top altitudes of stratiform precipitation are highly correlated with the zonal averaged air temperature and sea surface temperature. Additionally, the mean storm tops of higher altitudes correspond with larger mean rain rates for both convective and stratiform precipitation at the seasonal scale. Such relationship satisfies the quadratic functions with a correlation coefficient of 0.9. On the basis of this relationship, the summer mean rain rates are retrieved from storm top altitudes, which are 1-3 mm/h and 0.3-0.9 mm/h smaller than the observed ones, for convective and stratiform precipitation, respectively. These results suggest that the quadratic function between storm top altitudes and rain rates have potential applications in precipitation parameterization of models and climatic studies.

  11. Anaerobic performance at altitude.

    PubMed

    Coudert, J

    1992-10-01

    Anaerobic metabolism is usually evaluated by the determination of the anaerobic capacity and the maximal anaerobic mechanical external power (Wmax). Conflicting results are reported on anaerobic capacity evaluated by maximal oxygen deficit and debt, and maximal blood lactate concentration during acute or chronic hypoxia (acclimatized subjects). Data on muscle biopsies (lactate concentration, changes in ATP, phosphocreatine and glycogen stores, glycolytic enzyme activities) and the few studies on lactate flux give in most cases evidence of a non-alteration of the anaerobic capacity for altitudes up to 5,500 m. No differences are observed in Wmax measured at high altitudes up to 5,200 m during intense short-term exercises: (1) jumps on a force platform which is a good indicator of alactic Wmax, and (2) 7-10 s sprints (i.e. force-velocity test) which solicit alactic metabolism but also lactic pathway. For exercises of duration equal or more than 30 s (i.e. Wingate test), there are conflicting results because a lower participation of aerobic metabolism during this test at high altitude can interfere with anaerobic performance. In conclusion, we can admit that anaerobic performances are not altered by high altitudes up to 5,200 m if the length of exposure does not exceed 5 weeks. After this period, muscle mass begins to decrease.

  12. Cardiovascular medicine at high altitude.

    PubMed

    Whayne, Thomas F

    2014-07-01

    Altitude physiology began with Paul Bert in 1878. Chronic mountain sickness (CMS) was defined by Carlos Monge in the 1940s in the Peruvian Andes as consisting of excess polycythemia. Hurtado et al performed studies in the Peruvian Andes in the 1950s to 1960s which defined acclimatization in healthy altitude natives, including polycythemia, moderate pulmonary hypertension, and low systemic blood pressure (BP). Electrocardiographic changes of right ventricular hypertrophy (RVH) were noted. Acclimatization of newcomers to altitude involves hyperventilation stimulated by hypoxia and is usually benign. Acute mountain sickness (AMS) in travelers to altitude is characterized by hypoxia-induced anorexia, dyspnea, headache, insomnia, and nausea. The extremes of AMS are high-altitude cerebral edema and high-altitude pulmonary edema. The susceptible high-altitude resident can lose their tolerance to altitude and develop CMS, also referred to as Monge disease. The CMS includes extreme polycythemia, severe RVH, excess pulmonary hypertension, low systemic BP, arterial oxygen desaturation, and hypoventilation.

  13. Ear - blocked at high altitudes

    MedlinePlus

    ... ears; Flying and blocked ears; Eustachian tube dysfunction - high altitude ... to the eardrum) and the back of the nose and upper throat. ... down from high altitudes. Chewing gum the entire time you are ...

  14. Comparison of sprite initiation altitudes between observations and models

    NASA Astrophysics Data System (ADS)

    Gamerota, W. R.; Cummer, S. A.; Li, J.; Stenbaek-Nielsen, H. C.; Haaland, R. K.; McHarg, M. G.

    2011-02-01

    Simultaneous analyses of measured sprite initiation altitudes with predicted initiation altitudes from simulations enable an examination of our understanding of the sprite initiation mechanism and the modeling techniques to simulate this mesospheric electrical phenomenon. In this work, we selected a subset of sprites optically observed from Langmuir Laboratory, NM; locations near Las Vegas, NM, in 2007 and near Portales, NM, in 2008; and a Duke University field station. The sprites were observed by high-speed imaging with time resolutions of at least 1 ms and by low light level imagers. Sprite initiation altitudes were determined by triangulation between Langmuir Laboratory and either Portales or Las Vegas, while star field analysis determined the approximate measured initiation altitudes for Duke observations. These video observations were coordinated with electromagnetic field measurements from Yucca Ridge Field Station and Duke University, respectively. With a 2-D finite difference time domain model, we simulated the lightning-driven electric fields and predict the likely altitude of sprite initiation and compare these findings with the measured initiation altitude of each sprite analyzed. Of 20 discrete sprite events analyzed, both the measured and the simulation-predicted initiation altitudes indicate that long-delayed sprites tend to initiate at lower altitude. The average discrepancy between the measurements and the simulation results is 0.35 km with a standard deviation of 3.6 km. This consistency not only confirms previous results about the relationship between sprite initiation altitude and time delay but also helps to develop confidence in the models to reveal the sprite physics.

  15. High altitude diving depths.

    PubMed

    Paulev, Poul-Erik; Zubieta-Calleja, Gustavo

    2007-01-01

    In order to make any sea level dive table usable during high altitude diving, a new conversion factor is created. We introduce the standardized equivalent sea depth (SESD), which allows conversion of the actual lake diving depth (ALDD) to an equivalent sea dive depth. SESD is defined as the sea depth in meters or feet for a standardized sea dive, equivalent to a mountain lake dive at any altitude, such that [image omitted] [image omitted] [image omitted] Mountain lakes contain fresh water with a relative density that can be standardized to 1,000 kg m(-3), and sea water can likewise be standardized to a relative density of 1,033 kg m(-3), at the general gravity of 9.80665 m s(-2). The water density ratio (1,000/1,033) refers to the fresh lake water and the standardized sea water densities. Following calculation of the SESD factor, we recommend the use of our simplified diving table or any acceptable sea level dive table with two fundamental guidelines: 1. The classical decompression stages (30, 20, and 10 feet or 9, 6, and 3 m) are corrected to the altitude lake level, dividing the stage depth by the SESD factor. 2. Likewise, the lake ascent rate during diving is equal to the sea ascent rate divided by the SESD factor.

  16. Observations of High-altitude Negative Lightning Leaders

    NASA Astrophysics Data System (ADS)

    Edens, H. E.

    2011-12-01

    On 20 August 2010 a high-speed video recording was made of a bolt-from-the-blue (BFB) lightning flash where the negative leader exited the cloud near 9 km altitude and could be observed in clear air along most of its path to ground. The observation was augmented by data from Langmuir Laboratory's 3-D Lightning Mapping Array (LMA) as well as slow and fast Delta-E and broadband (up to 100 MHz) electric field waveform recordings. The various data sets are correlated in time and time-correlated LMA data is overlaid on the video frames, yielding a spectacular animation of a negative leader as it propagates from 9 km altitude down into air of increasingly higher pressure, contacting ground at 1.5 km altitude. At 9 km altitude, the tip of the negative leader exhibits impulsive emissions of light and retrograde luminosity waves that are seen to travel backward along the channel, away from the leader tip. As the leader propagates down in altitude the light emissions from the leader tip become more continuous in nature and the leader starts branching profusely. The leader velocity, on the order of 10^5 m/s, did not appear to change significantly. At the same storm, 30 minutes before the BFB flash occurred, a photograph was obtained of another negative leader from an intracloud (IC) flash that exited the cloud near the top, propagated several kilometers upward along a slanted path and terminated in clear air at 11 km altitude. The photograph was made with a Nikon D700 digital camera set at high sensitivity. The individual leader steps, which are on the order of 200 m length, are resolved as relatively straight segments of channel between sharp bends. At each bend (or kink) in the channel, clusters of 5 to 8 blue streamer filaments occur that are on the order of 100 m length. Small branches occur at most of the channel bends. One bend in the channel is accompanied by a space stem with blue streamers at both ends. The positive streamer emanating from the space stem and reaching

  17. On the High- and Low- Altitude Limits of the Auroral Electric Field Region

    NASA Technical Reports Server (NTRS)

    Reiff, P. H.; Lu, G.; Burch, J. L.; Winningham, J. D.; Frank, L. A.; Craven, J. D.; Peterson, W. K.; Heelis, R. A.

    1993-01-01

    Using measurements from the High Altitude Plasma Instrument (HAPI) on the Dynamics-Explorer 1 (DE-1) spacecraft and the Low Altitude Plasma Instrument (LAPI) on Dynamics Explorer 2 (DE 2), we investigate both die high altitude and low altitude extents of the auroral acceleration region. To infer the high altitude limit, we searched the HAPI data base for evidence of upward-directed auroral electric fields located above the spacecraft when the HAPI spacecraft is above 9000 km altitude. We find that such acceleration is common when DE-1 flies through die auroral oval at an altitude of 9,000-11,000 km. At altitudes above 11,000 km, the fraction of the orbits with evidence of at least a 1000 V potential drop above the spacecraft falls, becoming essentially zero above an altitude of 15,000 km. Above that altitude, small (100 V) potential drops are frequently observed, but only rarely are approx. 1 kV potentials observed, typically associated with polar cap or 'theta' arcs or westward traveling surges. To investigate the low-altitude limit of the auroral acceleration region, we use conjunctions of DE 1 and DE 2 along auroral field lines and match the upgoing fluxes of ionospheric ions observed by DE 2 with the flux of accelerated upgoing ions observed at DE 1. Calculating the ionospheric scale height from the ion and electron temperatures and assuming that the parallel flow velocity is independent of height above 800 km, we calculate the altitude at which the upwelling ionospheric ions are effectively completely lost to upward acceleration. The initial lowest-altitude acceleration process could be either a perpendicular acceleration or a parallel electric field, but it must be sufficient to give the entire distribution escape energy. We find that in the two cases studied, near the region of peak auroral potential drop the altitude of this acceleration was around 1700 km (near the O/H neutral crossover altitude), but was significantly higher (approx. 2000 km) near the

  18. On the high- and low-altitude limits of the auroral electric field region

    NASA Astrophysics Data System (ADS)

    Reiff, P. H.; Lu, G.; Burch, J. L.; Winningham, J. D.; Frank, L. A.; Craven, J. D.; Peterson, W. K.; Heelis, R. A.

    Using measurements from the High Altitude Plasma Instrument (HAPI) on the Dynamics-Explorer 1 (DE-1) spacecraft and the Low Altitude Plasma Instrument (LAPI) on Dynamics Explorer 2 (DE 2), we investigate both the high altitude and low altitude extents of the auroral acceleration region. To infer the high altitude limit, we searched the HAPI data base for evidence of upward-directed auroral electric fields located above the spacecraft when the HAPI spacecraft is above 9000 km altitude. We find that such acceleration is common when DE-1 flies through the auroral oval at an altitude of 9,000-11,000 km. At altitudes above 11,000 km, the fraction of the orbits with evidence of at least a 1000 V potential drop above the spacecraft falls, becoming essentially zero above an altitude of 15,000 km. Above that altitude, small (100 V) potential drops are frequently observed, but only rarely are -1 kV potentials observed, typically associated with polar cap or "theta" arcs or westward traveling surges. To investigate the low-altitude limit of the auroral acceleration region, we use conjunctions of DE 1 and DE 2 along auroral field lines and match the upgoing fluxes of ionospheric ions observed by DE 2 with the flux of accelerated upgoing ions observed at DE 1. Calculating the ionospheric scale height from the ion and electron temperatures and assuming that the parallel flow velocity is independent of height above 800 km, we calculate the altitude at which the upwelling ionospheric ions are effectively completely lost to upward acceleration. The initial lowest-altitude acceleration process could be either a perpendicular acceleration or a parallel electric field, but it must be sufficient to give the entire distribution escape energy. We find that in the two cases studied, near the region of peak auroral potential drop the altitude of this acceleration was around 1700 km (near the O/H neutral crossover altitude), but was significantly higher (˜2000 km) near the edges of the arc

  19. Peregrine 100-km Sounding Rocket Project

    NASA Technical Reports Server (NTRS)

    Zilliac, Gregory

    2012-01-01

    The Peregrine Sounding Rocket Program is a joint basic research program of NASA Ames Research Center, NASA Wallops, Stanford University, and the Space Propulsion Group, Inc. (SPG). The goal is to determine the applicability of this technology to a small launch system. The approach is to design, build, and fly a stable, efficient liquefying fuel hybrid rocket vehicle to an altitude of 100 km. The program was kicked off in October of 2006 and has seen considerable progress in the subsequent 18 months. This research group began studying liquifying hybrid rocket fuel technology more than a decade ago. The overall goal of the research was to gain a better understanding of the fundamental physics of the liquid layer entrainment process responsible for the large increase in regression rate observed in these fuels, and to demonstrate the effect of increased regression rate on hybrid rocket motor performance. At the time of this reporting, more than 400 motor tests were conducted with a variety of oxidizers (N2O, GOx, LOx) at ever increasing scales with thrust levels from 5 to over 15,000 pounds (22 N to over 66 kN) in order to move this technology from the laboratory to practical applications. The Peregrine program is the natural next step in this development. A number of small sounding rockets with diameters of 3, 4, and 6 in. (7.6, 10.2, and 15.2 cm) have been flown, but Peregrine at a diameter of 15 in. (38.1 cm) and 14,000-lb (62.3-kN) thrust is by far the largest system ever attempted and will be one of the largest hybrids ever flown. Successful Peregrine flights will set the stage for a wide range of applications of this technology.

  20. 45 Km Horizontal Path Optical Link Experiment

    NASA Technical Reports Server (NTRS)

    Biswas, A.; Ceniceros, J.; Novak, M.; Jeganathan, M.; Portillo, A.; Erickson, D.; Depew, J.; Sanii, B.; Lesh, J. R.

    2000-01-01

    Mountain-top to mountain-top optical link experiments have been initiated at JPL, in order to perform a systems level evaluation of optical communications. Progress made so far is reported. ne NASA, JPL developed optical communications demonstrator (OCD) is used to transmit a laser signal from Strawberry Peak (SP), located in the San Bernadino mountains of California. This laser beam is received by a 0.6 m aperture telescope at JPL's Table Mountain Facility (TMF), located in Wrightwood, California. The optical link is bi-directional with the TMF telescope transmitting a continuous 4-wave (cw) 780 run beacon and the OCD sending back a 840 nm, 100 - 500 Mbps pseudo noise (PN) modulated, laser beam. The optical link path is at an average altitude of 2 km above sea level, covers a range of 46.8 km and provides an atmospheric channel equivalent to approx. 4 air masses. Average received power measured at either end fall well within the uncertainties predicted by link analysis. The reduction in normalized intensity variance (sigma(sup 2, sub I)) for the 4-beam beacon, compared to each individual beam, at SP, was from approx. 0.68 to 0.22. With some allowance for intra-beam mis-alignment, this is consistent with incoherent averaging. The sigma(sup2, sub I) measured at TMF approx. 0.43 +/- 0.22 exceeded the expected aperture averaged value of less than 0.1, probably because of beam wander. The focused spot sizes of approx. 162 +/- 6 microns at the TMF Coude and approx. 64 +/- 3 microns on the OCD compare to the predicted size range of 52 - 172 microns and 57 - 93 microns, respectively. This is consistent with 4 - 5 arcsec of atmospheric "seeing". The preliminary evaluation of OCD's fine tracking indicates that the uncompensated tracking error is approx. 3.3 micro rad compared to approx. 1.7 micro rad observed in the laboratory. Fine tracking performance was intermittent, primarily due to beacon fades on the OCD tracking sensor. The best bit error rates observed while

  1. Clinical practice: Acute high-altitude illnesses.

    PubMed

    Bärtsch, Peter; Swenson, Erik R

    2013-06-13

    A 45-year-old healthy man wishes to climb Mount Kilimanjaro (5895 m) in a 5-day period, starting at 1800 m. The results of a recent exercise stress test were normal; he runs 10 km 4 or 5 times per week and finished a marathon in less than 4 hours last year. He wants to know how he can prevent becoming ill at high altitude and whether training or sleeping under normobaric hypoxic conditions in the weeks before the ascent would be helpful. What would you advise?

  2. High-Altitude Cassini Radar Imaging of Titan

    NASA Astrophysics Data System (ADS)

    West, R. D.; Stiles, B.; Anderson, Y.; Boehmer, R.; Callahan, P.; Gim, Y.; Hamilton, G.; Hensley, S.; Janssen, M.; Johnson, W. T.; Kelleher, K.; Lorenz, R.; Ostro, S.; Paganelli, F.; Shaffer, S.; Wye, L.; Zebker, H.

    2006-12-01

    The Cassini spacecraft is now about halfway through its primary Tour of the Saturn system. By the time of this meeting, the radar instrument will have collected seven synthetic aperture strips during close flyby's, with 13 more to come. These images have resolutions as fine as 300 m. We present here data acquired using another imaging mode, very high altitude synthetic aperture radar (SAR) imaging, which extends imaging radar coverage and increases coincidental coverage with other Cassini imaging instruments such as VIMS and ISS. We also discuss calibration of SAR images and other radar data from additional engineering observations. Here we examine the performance trade-offs, special processing issues, and science potential of the high- altitude image observations, and the latest results from the calibration data. The high-altitude data collections are distinct from the normal Titan radar images because the range is much larger (around 20,000 km vs 950 km to 5000 km for normal SAR passes). To increase the signal to noise ratio in these circumstances, the radar operates in the lowest bandwidth scatterometer mode while spacecraft pointing control is used to slowly pan the central beam across a small swath. These high altitude images incorporate 150-200 independent looks in order to let us discriminate features that may lie below the noise floor. So far, three high-altitude images have been acquired, during Titan flyby's T12, T13, and T15. In T12 imaging was attempted from 37000 km with an effective resolution around 5 km. In T13 the Huygens Probe landing site was imaged from 11000 km with effective resolution of 1 2 km. In T15 the Tsegehi area was imaged from 20000 km with effective resolution of 2 -3 km. Additional high altitude image segments are also planned during the T19 and T20 Titan flyby's. The calibration observations are conducted independently or coupled with a distant icy satellite observation. They consist of receive-only data in all four bandwidths

  3. Altitude and latitude dependence of the equatorial electrojet

    NASA Astrophysics Data System (ADS)

    Singh, A.; Cole, K. D.

    1988-07-01

    A self-consistent and high-resolution dynamo model is used to investigate the effects of day-to-day or seasonal variation of altitude and latitude profiles of the E-plasma density in the equatorial ionosphere on equatorial electrojet (EEJ) structure. Variations in the E-layer peak altitude and amplitude are shown to significantly affect EEJ structure. The results indicate that, for any shape, the EEJ peak appears at or below the E-layer peak altitude. Distinct double peaks occur in the EEJ structure if the E-layer peak is above 105 km or if the gradient is large. The effect of the latitudinal variation of the integrated conductivities of ionospheric field lines upon the amplitude and altitude of the EEJ peak is discussed.

  4. Chicxulub High-Altitude Ballistic Ejecta from Central Belize

    NASA Technical Reports Server (NTRS)

    Pope, K. O.; Ocampo, A. C.

    2000-01-01

    Chicxulub ejecta are found in central Belize, 475 km southeast of the impact crater center. These deposits are ballistic ejecta launched along high-altitude trajectories above the atmosphere and deposited as a discontinuous sheet on the terminal Cretaceous land surface.

  5. Chicxulub High-Altitude Ballistic Ejecta from Central Belize

    NASA Technical Reports Server (NTRS)

    Pope, K. O.; Ocampo, A. C.

    2000-01-01

    Chicxulub ejecta are found in central Belize, 475 km southeast of the impact crater center. These deposits are ballistic ejecta launched along high-altitude trajectories above the atmosphere and deposited as a discontinuous sheet on the terminal Cretaceous land surface.

  6. Satellite altitude determination uncertainties

    NASA Technical Reports Server (NTRS)

    Siry, J. W.

    1972-01-01

    Satellite altitude determination uncertainties will be discussed from the standpoint of the GEOS-C satellite, from the longer range viewpoint afforded by the Geopause concept. Data are focused on methods for short-arc tracking which are essentially geometric in nature. One uses combinations of lasers and collocated cameras. The other method relies only on lasers, using three or more to obtain the position fix. Two typical locales are looked at, the Caribbean area, and a region associated with tracking sites at Goddard, Bermuda and Canada which encompasses a portion of the Gulf Stream in which meanders develop.

  7. Effects of high altitude and exercise on marksmanship.

    PubMed

    Tharion, W J; Hoyt, R W; Marlowe, B E; Cymerman, A

    1992-02-01

    The effects of exercise and high altitude (3,700 m to 4,300 m) on marksmanship accuracy and sighting time were quantified in 16 experienced marksmen. Subjects dry-fired a disabled rifle equipped with a laser-based system from a free-standing position. The 2.3-cm circular target was at a distance of 5 m. Marksmanship was assessed under the following conditions: 1) at rest at sea level; 2) immediately after a 21-km run/walk ascent from 1,800 m to 4,300 m elevation; 3) at rest during days 1 to 3 at altitude; 4) at rest during days 14 to 16 at altitude; and 5) immediately after a second ascent after 17 d at altitude. Exercise reduced marksmanship accuracy (p less than 0.05) but did not affect sighting time. Acute altitude exposure reduced marksmanship accuracy, and decreased sighting time (p less than 0.05). However, after residence at altitude, accuracy and sighting time at rest returned to sea level values. Exercise and acute altitude exposure had similar but independent detrimental effects on marksmanship.

  8. DLR HABLEG- High Altitude Balloon Launched Experimental Glider

    NASA Astrophysics Data System (ADS)

    Wlach, S.; Schwarzbauch, M.; Laiacker, M.

    2015-09-01

    The group Flying Robots at the DLR Institute of Robotics and Mechatronics in Oberpfaffenhofen conducts research on solar powered high altitude aircrafts. Due to the high altitude and the almost infinite mission duration, these platforms are also denoted as High Altitude Pseudo-Satellites (HAPS). This paper highlights some aspects of the design, building, integration and testing of a flying experimental platform for high altitudes. This unmanned aircraft, with a wingspan of 3 m and a mass of less than 10 kg, is meant to be launched as a glider from a high altitude balloon in 20 km altitude and shall investigate technologies for future large HAPS platforms. The aerodynamic requirements for high altitude flight included the development of a launch method allowing for a safe transition to horizontal flight from free-fall with low control authority. Due to the harsh environmental conditions in the stratosphere, the integration of electronic components in the airframe is a major effort. For regulatory reasons a reliable and situation dependent flight termination system had to be implemented. In May 2015 a flight campaign was conducted. The mission was a full success demonstrating that stratospheric research flights are feasible with rather small aircrafts.

  9. Modeling Venus' Atmosphere at Cloud Altitudes with a New Middle Atmosphere GCM

    NASA Astrophysics Data System (ADS)

    Parish, H. F.; Mitchell, J. L.

    2017-05-01

    We discuss simulations using a new Venus Middle atmosphere Model (VMM), which simulates the atmosphere from just below the cloud deck to around 100 km altitude, with the aim of focusing on the dynamics at cloud levels and above.

  10. Active Learning in the Atmospheric Science Classroom and beyond through High-Altitude Ballooning

    ERIC Educational Resources Information Center

    Coleman, Jill S. M.; Mitchell, Melissa

    2014-01-01

    This article describes the implementation of high-altitude balloon (HAB) research into a variety of undergraduate atmospheric science classes as a means of increasing active student engagement in real-world, problem-solving events. Because high-altitude balloons are capable of reaching heights of 80,000-100,000 ft (24-30 km), they provide a…

  11. Active Learning in the Atmospheric Science Classroom and beyond through High-Altitude Ballooning

    ERIC Educational Resources Information Center

    Coleman, Jill S. M.; Mitchell, Melissa

    2014-01-01

    This article describes the implementation of high-altitude balloon (HAB) research into a variety of undergraduate atmospheric science classes as a means of increasing active student engagement in real-world, problem-solving events. Because high-altitude balloons are capable of reaching heights of 80,000-100,000 ft (24-30 km), they provide a…

  12. Brain Food at High Altitude.

    PubMed

    Jain, Vishal

    2016-01-01

    Scenic view at high altitude is a pleasure to the eyes, but it has some shortcoming effects as well. High altitude can be divided into different categories, i.e., high altitude (3000-5000 ft), very high altitude (5000-8000 ft), and extreme altitude (above 8000 ft). Much of the population resides at high altitude, and others go there for tourism. Military personnel are also posted there to defend boundaries. As we ascent to high altitude, partial pressure of oxygen reduces, whereas concentration remains the same; this reduces the availability of oxygen to different body parts. This pathophysiological condition is known as hypobaric hypoxia (HH) which leads to oxidative stress and further causes cognitive dysfunction in some cases. Hypoxia causes neurodegeneration in different brain regions; however, the hippocampus is found to be more prone in comparison to other brain regions. As the hippocampus is affected most, therefore, spatial memory is impaired most during such condition. This chapter will give a brief review of the damaging effect of high altitude on cognition and also throw light on possible herbal interventions at high altitude, which can improve cognitive performance as well as provide protection against the deteriorating effect of hypobaric hypoxia at high altitude.

  13. Range Reference Atmosphere 0-30 km Altitude, Eglin AFB, Florida

    DTIC Science & Technology

    1983-08-01

    the entire area under the bivariate normal density function [equation (9)] is unity, upon integration for a given prob- ability ellipse, that given...ellipse contains p-percent of the total area . In the wind statistics, p-percent of the wind vectors fall within the speci- fied probability ellipse... distribucion of each of the six thermodynamic RRA param- * eters is described by its mean value, its standard deviation, and its skewness. Several of these

  14. Taquac, Guam Island. Range Reference Atmosphere 0-30 Km Altitude

    DTIC Science & Technology

    1983-09-01

    Computation of Statistical Parameters ...... ..... ................ 8 C. Statistical Wind Models ................. 10 D. Statistical Parameters With...32 C. Computation of Statistical Parameters for Tables 1I and III ..................... 36 D. Derived Monthly Mean and Annual...statistical modeling techniques have been made because of the general availability of high-speed electronic computers . These have led to the adoption of

  15. The drag coefficient of cylindrical spacecraft in orbit at altitudes greater than 150 km

    NASA Technical Reports Server (NTRS)

    Herrero, F. A.

    1983-01-01

    The spacecraft of the Geopotential Research Mission (GRM) are cylindrical in form and designed to fly with their longitudinal axes parallel to their direction of flight. The ratio of length to diameter of these spacecraft is roughly equal to 5.0. Other spacecraft previously flown had corresponding ratios roughly equal to 1.0, and therefore the drag produced by impacts on the lateral surfaces of those spacecraft was not as large as it will be on the GRM spacecraft. Since the drag coefficient is essentially the drag force divided by the frontal area in flight, lateral impacts, when taken into account make the GRM drag coefficient significantly larger than the coefficients used before for shorter spacecraft. A simple formula is derived for the drag coefficient of a cylindrical body flying with its long axis along the direction of flight, and it is used to estimate the drag for the GRM. The formula shows that the drag due to lateral surface impacts depends on the ratio of length-to-diameter and on a coefficient C sub LS (lateral surface impact coefficient) which can be determined from previous cylindrical spacecraft flown with the same attitude, or can be obtained from laboratory measurements of momentum accommodation coefficients.

  16. Range Reference Atmosphere, 0.66 Km Altitude, Ascension Island, South Atlantic

    DTIC Science & Technology

    1984-01-01

    Windspeed or modulus of wind vector, a scalar quantity WBAR - The mean value of windspeed in table I X - A general component variable or coordinate axis Y ...A general component variable or coordinate axis - A general component mean value in the [x, y ) coordinate system f - A general component mean value in...the [x, y ] coordinate system a (alpha) - Rotation angle for the [x, y ] coordinate system 6A LO TABLE A. (concluded) 8 (theta) - Wind direction in the

  17. Microphysical Model of the Venus clouds between 40km and 80km

    NASA Astrophysics Data System (ADS)

    McGouldrick, Kevin

    2013-10-01

    I am continuing to adapt the Community Aerosol and Radiation Model for Atmospheres (CARMA) to successfully simulate the multi-layered clouds of Venus. The present version of the one-dimensional model now includes a simple parameterization of the photochemicial production of sulfuric acid around altitudes of 62km, and its thermochemical destruction below cloud base. Photochemical production in the model is limited by the availability of water vapor and insolation. Upper cloud particles are introduced into the model via binary homogeneous nucleation, while the lower and middle cloud particles are created via activation of involatile cloud condensation nuclei. Growth by condensation and coagulation and coalescence are also treated. Mass loadings and particle sizes compare favorably with the in situ observations by the Pioneer Venus Large Probe Particle Size Spectrometer, and mixing ratios of volatiles compare favorably with remotely sensed observations of water vapor and sulfuric acid vapor. This work was supported by the NASA Planetary Atmospheres Program, grant number NNX11AD79G.

  18. Infectious Diseases at High Altitude.

    PubMed

    Basnyat, Buddha; Starling, Jennifer M

    2015-08-01

    Travel to elevations above 2,500 m is an increasingly common activity undertaken by a diverse population of individuals. These may be trekkers, climbers, miners in high-altitude sites in South America, and more recently, soldiers deployed for high-altitude duty in remote areas of the world. What is also being increasingly recognized is the plight of the millions of pilgrims, many with comorbidities, who annually ascend to high-altitude sacred areas. There are also 400 million people who reside permanently in high mountain ranges, which cover one-fifth of the Earth's surface. Many of these high-altitude areas are in developing countries, for example, the Himalayan range in South Asia. Although high-altitude areas may not harbor any specific infectious disease agents, it is important to know about the pathogens encountered in the mountains to be better able to help both the ill sojourner and the native high-altitude dweller. Often the same pathogens prevalent in the surrounding lowlands are found at high altitude, but various factors such as immunomodulation, hypoxia, poor physiological adaptation, and harsh environmental stressors at high altitude may enhance susceptibility to these pathogens. Against this background, various gastrointestinal, respiratory, dermatological, neurological, and other infections encountered at high altitude are discussed.

  19. Altitude release mechanism

    DOEpatents

    Kulhanek, Frank C.

    1977-01-01

    An altitude release mechanism for releasing a radiosonde or other measuring instrument from a balloon carrying it up into the atmosphere includes a bottle partially filled with water, a tube sealed into the bottle having one end submerged in the water in the bottle and the free end extending above the top of the bottle and a strip of water-disintegrable paper held within the free end of the tube linking the balloon to the remainder of the package. As the balloon ascends, the lowered atmospheric air pressure causes the air in the bottle to expand, forcing the water in the bottle up the tubing to wet and disintegrate the paper, releasing the package from the balloon.

  20. High Altitude Emissions

    NASA Technical Reports Server (NTRS)

    Bulzan, Dan

    2007-01-01

    An overview of emissions related research being conducted as part of the Fundamental Aeronautics Supersonics Project is presented. The overview includes project objectives, milestones, and descriptions of major research areas. The overview also includes information on the emissions research being conducted under NASA Research Announcements. Technical challenges include: 1) Environmental impact of supersonic cruise emissions is greater due to higher flight altitudes which makes emissions reduction increasingly important. 2) Accurate prediction tools to enable combustor designs that reduce emissions at supersonic cruise are needed as well as intelligent systems to minimize emissions. 3) Combustor operating conditions at supersonic cruise are different than at subsonic cruise since inlet fuel and air temperatures are considerably increased.

  1. High Altitude Plasma Instrument (HAPI) data analysis. Final report

    SciTech Connect

    Burch, J.L.

    1994-01-01

    The objectives of the Dynamics Explorer mission are to investigate the coupling of energy, mass, and momentum among the earth's magnetosphere, ionosphere, and upper atmosphere. At launch, on August 3, 1981, DE-1 was placed into an elliptical polar orbit having an apogee of 23,130 km to allow global auroral imaging and crossings of auroral field lines at altitudes of several thousand kilometers. At the same time DE-2 was placed into a polar orbit, coplanar with that of DE-1 but with a perigee altitude low enough (309 km) for neutral measurements and an apogee altitude of 1012 km. The DE-1 High Altitude Plasma Instrument (HAPI) provided data on low and medium energy electrons and ions from August 13, 1981 until December 1, 1981, when a high-voltage failure occured. Analysis of HAPI data for the time period of this contract has produced new results on the source mechanisms for electron conical distributions, particle acceleration phenomena in auroral acceleration regions, Birkeland currents throughout the nightside auroral regions, the source region for auroral kilometric radiation (AKR), and plasma injection phenomena in the polar cusp.

  2. El Chichon and 'mystery cloud' aerosols between 30 and 55 km Global observations from the SME visible spectrometer

    NASA Technical Reports Server (NTRS)

    Clancy, R. T.

    1986-01-01

    Visible limb radiances measured by the Solar Mesosphere Explorer (SME) are used to obtain volume scattering ratios for aerosol loading in the 30-55 km altitude range of the stratosphere. Global maps of these ratios are presented for the period January 1982 to August 1984. Significant aerosol scattering from the 'mystery cloud' and El Chichon aerosol layers are found above 30 km. A timescale of approximately 2 months between the appearance of the aerosol at 30.5 km and at 37.5 km is consistent with vertical transport of aerosol or vapor by eddy diffusion above 30 km. An anticorrelation exists between aerosol scattering and stratospheric temperatures. Periods of lower stratospheric temperatures may account for the formation of aerosol between 40 and 55 km altitude.

  3. Altitude measurement for model rocketry

    NASA Astrophysics Data System (ADS)

    Caughey, David A.

    2007-05-01

    The simple, ballistic time-of-flight equation for the maximum altitude of a vertically launched rocket neglects the effects of atmospheric drag. We show that the error introduced by using this equation to estimate the maximum altitude is typically less than 1% because of the effective cancellations of timing errors during the ascent and descent of the rocket.

  4. [Altitude and the cardiovascular system].

    PubMed

    Richalet, Jean-Paul

    2012-06-01

    A stay at high altitude exposes an individual to various environmental changes (cold, exercise, isolation) but the most stressful for the body is hypoxia. However, the cardiovascular system yields some efficient mechanisms of acclimatization to oxygen lack. Hypoxia activates the adrenergic system and induces a tachycardia that decreases during a prolonged stay at altitude. The desensitization of the adrenergic system leads to a decrease in maximal heart rate and a protection of the myocardium against an energy disequilibrium that could be potentially harmful for the heart. Hypoxia induces a peripheral vasodilation and a pulmonary vasoconstriction, leading to few changes in systemic blood pressure and an increase in pulmonary blood pressure (PHT) that can contribute to a high altitude pulmonary edema. Advice to a cardiac patient who plans to go to high altitude should take into account that all diseases aggravated by increased adrenergic activity or associated with a PHT or a hypoxemia (right-to-left shunt) will be aggravated at high altitude. As altitude increases, a patient with a coronary disease will present an ischemic threshold for a lower power output during an EKG exercise test. The only test allowing predicting the tolerance to high altitude is the hypoxia exercise test realized at 30% of maxVO(2)and at an equivalent altitude of 4,800m.

  5. The GRAD high-altitude balloon flight over Antarctica

    NASA Technical Reports Server (NTRS)

    Eichhorn, G.; Coldwell, R. L.; Dunnam, F. E.; Rester, A. C.; Trombka, J. I.; Starr, R.

    1989-01-01

    The Gamma Ray Advanced Detector (GRAD) consists of a n-type germanium detector inside an active bismuth-germanate Compton and charged particle shield with additional active plastic shielding across the aperture. It will be flown on a high-altitude balloon at 36 km altitude at a latitude of 78 deg S over Antarctica for observations of gamma radiation emitted by the radioactive decay of Co-56 in the supernova SN1987A, for assessment of the performance of bismuth-germanate scintillation material in the radiation environment of near space, for gathering information on the gamma-ray background over Antarctica, and for testing fault-tolerant software.

  6. Radiation measurements aboard NASA ER-2 high altitude aircraft with the Liulin-4J portable spectrometer.

    PubMed

    Uchihori, Y; Benton, E; Moeller, J; Bendrick, G

    2003-01-01

    The risks to aircrew health posed by prolonged exposure to low levels of ionizing radiation at aircraft altitudes have recently received renewed attention. Civil and military aircraft currently on the drawing board are expected to operate at higher altitudes (>12 km) and fly longer ranges than do existing aircraft, thereby exposing their crews to higher levels of ionizing radiation, for longer periods of time. We are currently carrying out dosimetric measurements of the ionizing radiation environment at approximately 20 km altitude using portable Si detectors aboard NASA's two ER-2 high altitude research aircraft. The instruments, Liulin-4J, have been extensively calibrated at several particle accelerators. With these instruments, we can measure not only absorbed dose, but also variation of the absorbed dose as a function of time. We report radiation dose measurements as function of time, altitude, and latitude for several ER-2 missions. c2003 COSPAR. Published by Elsevier Ltd. All rights reserved.

  7. Effects of altitude on the climbing performance of Monarch butterflies

    NASA Astrophysics Data System (ADS)

    Kang, Chang-Kwon; Sridhar, Madhu; Landrum, David; Aono, Hikaru

    2016-11-01

    Millions of Monarchs annually travel up to 4,000km, the longest migration distance among insects. They fly and overwinter at high altitudes. However, the aerodynamic mechanism enabling the long-range flight of Monarch butterflies is unknown. To study the effects of altitude on the aerodynamic performance of Monarch butterflies, a unique combination of a motion tracking system and a variable pressure chamber that allows controlling the density is used. The condition inside the chamber is systematically varied to simulate high altitude conditions up to 3,000 m. An optical tracking technique is used to characterize the climbing trajectories of freely flying Monarch butterflies. Customized reflective markers are designed to minimize the effects of marker addition. Flapping amplitude and frequency as well as climbing trajectories are measured. Lift acting on the butterfly is also determined by considering the force balance. Results show that the average flight speed and the Reynolds number, in general, decreased with the altitude, whereas, interestingly, the lift coefficient increased with the altitude. More detailed measurements and analyses will be performed in the future to explain the lift enhancement by flying at higher altitudes. This work is partly supported by NSF Grant CBET-1335572 and in part by CK's startup fund provided by UAH.

  8. [Classification of altitude decompression sickness].

    PubMed

    Katuntsev, V P

    2000-01-01

    The article is devoted to the discussion of principles of and approaches to classification of altitude decompression sickness (DCS), one of the most methodically formidable aspects of the problem. Based on his own multiyear experience in altitude DCS investigations and critical review of literature, the author reasons his concept of clinical classification of altitude DCS. The author's concept places emphasis on obligatory consideration of three stages in DCS development: A--pre-disease (the premorbid syndrome), B--uncomplicated (light) and C--complicated (severe) forms. The objective sign of the premorbid state is "silent" gas bubbles in organism detectable by ultrasonic devices. Signs of uncomplicated altitude DCS are musculoarticular pains, local edema and skin itching. Complicated altitude DCS is diagnosed by systemic (respiratory, neurological and cardiovascular) disorders.

  9. MESSENGER's Low-Altitude Campaign: Mercury at Unprecedented Close Range

    NASA Astrophysics Data System (ADS)

    Solomon, S. C.; Nittler, L. R.; Byrne, P. K.

    2014-12-01

    In March 2013, the MErcury Surface, Space ENvironment, GEochemistry and Ranging (MESSENGER) spacecraft began its Second Extended Mission (XM2) to acquire observations of Mercury's surface and interior at unprecedented spatial resolution and measurements of the planet's dynamic magnetosphere and exosphere at high temporal resolution during the peak and declining phase of the current solar cycle. XM2 is framed by six science questions, each motivated by discoveries and observations made during MESSENGER's Primary and First Extended Missions: (1) What active and recent processes have affected Mercury's surface? (2) How has the state of stress in Mercury's crust evolved over time? (3) How have compositions of volcanic materials on Mercury evolved over time? (4) What are the characteristics of volatile emplacement and sequestration in Mercury's north polar region? (5) What are the consequences of precipitating ions and energetic electrons at Mercury? (6) How do Mercury's exosphere and magnetosphere respond to both extreme and stable solar wind conditions during solar maximum and the declining phase of the solar cycle? Also since March 2013, the periapsis altitude, or closest approach distance to Mercury's surface, has declined progressively with each orbit, in response to the gravitational attraction of the Sun, although the rate of that decline depends on the angle between the Mercury-Sun line and MESSENGER's orbit plane. For the first year of XM2, no propulsive orbit-correction maneuvers (OCMs) were conducted to change the evolution of the spacecraft's orbital parameters. Because sufficient propellant remained at the end of that year to complete four periapsis-raising OCMs, a low-altitude campaign was designed to use those maneuvers to maximize the number of orbits for which the periapsis altitude is as low as 15-25 km. The periapsis altitude passed below 200 km altitude for the first time on 20 April 2014 and below 100 km altitude for the first time on 25 July 2014

  10. Extending MGS-TES Temperature Retrievals in the Martian Atmosphere up to 90 Km: Retrieval Approach and Results

    NASA Technical Reports Server (NTRS)

    Feofilov, A. G.; Kutepov, A. A.; Rezac, L.; Smith, M. D.

    2015-01-01

    This paper describes a methodology for performing a temperature retrieval in the Martian atmosphere in the 50-90 km altitude range using spectrally integrated 15 micrometers C02 limb emissions measured by the Thermal Emission Spectrometer (TES), the thermal infrared spectrometer on board the Mars Global Surveyor (MGS). We demonstrate that temperature retrievals from limb observations in the 75-90 km altitude range require accounting for the non-local thermodynamic equilibrium (non-LTE) populations of the C02(v2) vibrational levels. Using the methodology described in the paper, we have retrieved approximately 1200 individual temperature profiles from MGS TES limb observations in the altitude range between 60 and 90 km. 0ur dataset of retrieved temperature profiles is available for download in supplemental materials of this paper. The temperature retrieval uncertainties are mainly caused by radiance noise, and are estimated to be about 2 K at 60 km and below, 4 K at 70 km, 7 K at 80 km, 10 K at 85 km, and 20 K at 90 km. We compare the retrieved profiles to Mars Climate Database temperature profiles and find good qualitative agreement. Quantitatively, our retrieved profiles are in general warmer and demonstrate strong variability with the following values for bias and standard deviations (in brackets) compared to the Martian Year 24 dataset of the Mars Climate Database: 6 (+/-20) K at 60 km, 7.5 (+/-25) K at 65 km, 9 (+/-27) K at 70 km, 9.5 (+/-27) K at 75 km, 10 (+/-28) K at 80 km, 11 (+/-29) K at 85 km, and 11.5 (+/-31) K at 90 km. Possible reasons for the positive temperature bias are discussed. carbon dioxide molecular vibrations

  11. Neutrons from thunderstorms at low atmospheric altitudes and related doses at aircraft

    NASA Astrophysics Data System (ADS)

    Drozdov, A.; Grigoriev, A.

    2013-02-01

    We conduct a simulation of thunderstorm neutron flashes at the lowest atmospheric altitudes below 10 km. The neutron generation mechanism is based on the nowadays conventional idea of possibility for photonuclear reactions to proceed on the atmospheric components owing to TGF photons. Our modeling includes generation of neutrons from TGF and their further propagation with account of interaction with background nuclei. Using the calculation results we investigate the neutron flux properties with respect to problem of their registration, and predict the radiation environment caused by thunderstorm neutrons on altitudes of civil airflights. It is shown, that good conditions for the neutron flashes observation are provided from the 3 km altitude, and, possibly, the neutrons can be registered at ground level. We also found that thunderstorm-neutron-related effective dose can reach the value of 0.5 mSv in the region close to the TGF source if it is located at an altitude of 10 km.

  12. The altitude distribution of the Venus ultraviolet nightglow and implications on vertical transport

    NASA Technical Reports Server (NTRS)

    Gerard, J. C.; Stewart, A. I. F.; Bougher, S. W.

    1981-01-01

    The altitude distribution of the nitric oxide nightglow was measured with an ultraviolet spectrometer on board Pioneer Venus, in order to study the effects of the distribution on the Venus nightside lower thermosphere transport properties. Limb profiles were obtained with an 8 ms integration period on several orbits near periapsis. The observations were made between P minus 2 min and P plus 4 min, where altitude ranges between 150 and 350 km, and latitude varies from 24 degrees N to 9 degrees S. A method independent of the spacecraft attitude data was used to fit the observed limb profiles, and to find the altitude of the maximum of the layer (115 plus or minus 2 km), and the topside scale height (about 3 km). It is shown that downward transport by diffusion alone is not sufficient, and if vertical motion is parameterized by eddy diffusion, an eddy diffusion coefficient is deduced from the altitude of the layer.

  13. 28 CFR 0.70 - General functions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... than the Tax Court, of civil suits, and the handling of other matters, arising under the internal... forfeiture and civil penalty matters arising under laws relating to liquor, narcotics, gambling, and firearms...)(1) Enforcement of tax liens, and mandamus, injunctions, and other special actions or general matters...

  14. Auroral energy deposition and neutral composition changes observed simultaneously by ESRO 4 and AE-C at different altitudes

    NASA Technical Reports Server (NTRS)

    Trinks, H.; Mayr, H. G.; Kayser, D. C.; Potter, W. E.

    1977-01-01

    Neutral composition data obtained simultaneously from ESRO 4 and AE-C during geomagnetically disturbed conditions at different altitudes (160 and 230 km) are used to investigate the atmospheric response to geomagnetic storms and to infer information regarding the excitation mechanism. The data are compared with a theoretical model that estimates the composition effects in terms of wind induced diffusion. A parametric study was conducted bearing on the influence of energy deposition at different altitudes and with varying latitudinal extent. In one of the observed events the composition effects at 160 km are substantially smaller than at 230 km for which we inferred by comparison with the theory that the energy mainly was deposited at 150 km altitude over a wide latitude range. Another event required energy deposition at somewhat lower altitudes near 120 km with a more localized energy source. Significant variations of the turbopause level were not necessary to explain the observed variations.

  15. Energy at high altitude.

    PubMed

    Hill, N E; Stacey, M J; Woods, D R

    2011-03-01

    For the military doctor, an understanding of the metabolic effects of high altitude (HA) exposure is highly relevant. This review examines the acute metabolic challenge and subsequent changes in nutritional homeostasis that occur when troops deploy rapidly to HA. Key factors that impact on metabolism include the hypoxic-hypobaric environment, physical exercise and diet. Expected metabolic changes include augmentation of basal metabolic rate (BMR), decreased availability of oxygen in peripheral metabolic tissues, reduction in VO2 max, increased glucose dependency and lactate accumulation during exercise. The metabolic demands of exercise at HA are crucial. Equivalent activity requires greater effort and more energy than it does at sea level. Soldiers working at HA show high energy expenditure and this may exceed energy intake significantly. Energy intake at HA is affected adversely by reduced availability, reduced appetite and changes in endocrine parameters. Energy imbalance and loss of body water result in weight loss, which is extremely common at HA. Loss of fat predominates over loss of fat-free mass. This state resembles starvation and the preferential primary fuel source shifts from carbohydrate towards fat, reducing performance efficiency. However, these adverse effects can be mitigated by increasing energy intake in association with a high carbohydrate ration. Commanders must ensure that individuals are motivated, educated, strongly encouraged and empowered to meet their energy needs in order to maximise mission-effectiveness.

  16. High Altitude Dermatology.

    PubMed

    Singh, Lt Col G K

    2017-01-01

    Approximately, 140 million people worldwide live permanently at high altitudes (HAs) and approximately another 40 million people travel to HA area (HAA) every year for reasons of occupation, sports or recreation. In India, whole of Ladakh region, part of Northwest Kashmir, Northern part of Sikkim and Tenga valley of Arunachal are considered inhabited areas of HAA. The low quantity of oxygen, high exposure of ultraviolet (UV) light, very low humidity, extreme subzero temperature in winter, high wind velocity, make this region difficult for lowlanders as well as for tourists. Acute mountain sickness, HA pulmonary edema, HA cerebral edema, and thromboembolic conditions are known to occur in HA. However, enough knowledge has not been shared on dermatoses peculiar to this region. Xerosis, UV-related skin disorders (tanning, photomelanosis, acute and chronic sunburn, polymorphic light eruption, chronic actinic dermatitis, actinic cheilitis, etc.), cold injuries (frostbite, chilblains, acrocyanosis, erythrocyanosis, etc.) nail changes (koilonychias), airborne contact dermatitis, insect bite reaction, and skin carcinoma (basal cell carcinomas, squamous cell carcinomas, and also rarely malignant melanoma) are the dermatoses seen in HAAs. Early diagnosis and knowledge of HA dermatoses may prevent serious consequences of disease and improve the quality of life for the visitors as well as for native of the place.

  17. High altitude reconnaissance aircraft

    NASA Technical Reports Server (NTRS)

    Yazdo, Renee Anna; Moller, David

    1990-01-01

    At the equator the ozone layer ranges from 65,000 to 130,000 plus feet, which is beyond the capabilities of the ER-2, NASA's current high altitude reconnaissance aircraft. The Universities Space Research Association, in cooperation with NASA, is sponsoring an undergraduate program which is geared to designing an aircraft that can study the ozone layer at the equator. This aircraft must be able to cruise at 130,000 feet for six hours at Mach 0.7, while carrying 3,000 lbs. of payload. In addition, the aircraft must have a minimum range of 6,000 miles. In consideration of the novel nature of this project, the pilot must be able to take control in the event of unforeseen difficulties. Three aircraft configurations were determined to be the most suitable - a joined-wing, a biplane, and a twin-boom conventional airplane. The performance of each configuration was analyzed to investigate the feasibility of the project.

  18. High Altitude Dermatology

    PubMed Central

    Singh, Lt. Col. G K

    2017-01-01

    Approximately, 140 million people worldwide live permanently at high altitudes (HAs) and approximately another 40 million people travel to HA area (HAA) every year for reasons of occupation, sports or recreation. In India, whole of Ladakh region, part of Northwest Kashmir, Northern part of Sikkim and Tenga valley of Arunachal are considered inhabited areas of HAA. The low quantity of oxygen, high exposure of ultraviolet (UV) light, very low humidity, extreme subzero temperature in winter, high wind velocity, make this region difficult for lowlanders as well as for tourists. Acute mountain sickness, HA pulmonary edema, HA cerebral edema, and thromboembolic conditions are known to occur in HA. However, enough knowledge has not been shared on dermatoses peculiar to this region. Xerosis, UV-related skin disorders (tanning, photomelanosis, acute and chronic sunburn, polymorphic light eruption, chronic actinic dermatitis, actinic cheilitis, etc.), cold injuries (frostbite, chilblains, acrocyanosis, erythrocyanosis, etc.) nail changes (koilonychias), airborne contact dermatitis, insect bite reaction, and skin carcinoma (basal cell carcinomas, squamous cell carcinomas, and also rarely malignant melanoma) are the dermatoses seen in HAAs. Early diagnosis and knowledge of HA dermatoses may prevent serious consequences of disease and improve the quality of life for the visitors as well as for native of the place. PMID:28216727

  19. Measurement of Unsteady Blade Surface Pressure on a Single Rotation Large Scale Advanced Prop-fan with Angular and Wake Inflow at Mach Numbers from 0.02 to 0.70

    NASA Technical Reports Server (NTRS)

    Bushnell, P.; Gruber, M.; Parzych, D.

    1988-01-01

    Unsteady blade surface pressure data for the Large-Scale Advanced Prop-Fan (LAP) blade operation with angular inflow, wake inflow and uniform flow over a range of inflow Mach numbers of 0.02 to 0.70 is provided. The data are presented as Fourier coefficients for the first 35 harmonics of shaft rotational frequency. Also presented is a brief discussion of the unsteady blade response observed at takeoff and cruise conditions with angular and wake inflow.

  20. New AIM/CIPS global observations of gravity waves near 50-55 km

    NASA Astrophysics Data System (ADS)

    Randall, C. E.; Carstens, J.; France, J. A.; Harvey, V. L.; Hoffmann, L.; Bailey, S. M.; Alexander, M. J.; Lumpe, J. D.; Yue, J.; Thurairajah, B.; Siskind, D. E.; Zhao, Y.; Taylor, M. J.; Russell, J. M.

    2017-07-01

    This paper describes a new data set from the Aeronomy of Ice in the Mesosphere (AIM) Cloud Imaging and Particle Size (CIPS) instrument, from which gravity waves (GWs) at an altitude of 50-55 km can be inferred. CIPS is sensitive to GWs with horizontal wavelengths from 15 to 600 km and vertical wavelengths longer than 15 km. Several examples of GWs in CIPS observations are shown, including waves associated with the Andes Mountains, island topography, convection, the polar night jet, and the tropospheric jet stream. GW signatures in the CIPS data are shown to agree well with near-coincident but lower altitude measurements from the Atmospheric Infrared Sounder (AIRS) in June of 2016. Results suggest the power of combining CIPS measurements with those from other instruments to investigate GW filtering and propagation. The CIPS data set opens new areas of inquiry, enabling comprehensive investigations of GWs in the middle atmosphere on a near-global scale.

  1. Lung Disease at High Altitude

    PubMed Central

    Stream, JO; Luks, AM; Grissom, CK

    2016-01-01

    Large numbers of people travel to high altitudes, entering an environment of hypobaric hypoxia. Exposure to low oxygen tension leads to a series of important physiologic responses that allow individuals to tolerate these hypoxic conditions. However, in some cases hypoxia triggers maladaptive responses that lead to various forms of acute and chronic high altitude illness, such as high-altitude pulmonary edema or chronic mountain sickness. Because the respiratory system plays a critical role in these adaptive and maladaptive responses, patients with underlying lung disease may be at increased risk for complications in this environment and warrant careful evaluation before any planned sojourn to higher altitudes. In this review, we describe respiratory disorders that occur with both acute and chronic exposures to high altitudes. These disorders may occur in any individual who ascends to high altitude, regardless of his/her baseline pulmonary status. We then consider the safety of high-altitude travel in patients with various forms of underlying lung disease. The available data regarding how these patients fare in hypoxic conditions are reviewed, and recommendations are provided for management prior to and during the planned sojourn. PMID:20477353

  2. Peak expiratory flow at altitude.

    PubMed

    Thomas, P S; Harding, R M; Milledge, J S

    1990-08-01

    The mini Wright peak flow meter is a useful, portable instrument for field studies but being sensitive to air density will under-read at altitude. True peak expiratory flow will increase at altitude, however, because of the decreased air density, given that dynamic resistance is unchanged. The effect of simulated altitude on peak expiratory flow (PEF) was determined in six subjects with both the mini Wright meter and a volumetric spirometer (which is unaffected by air density). With increasing altitude PEF as measured by the spirometer increased linearly with decreasing pressure, so that at a barometric pressure of 380 mm Hg* (half an atmosphere, corresponding to an altitude of 5455 m) there was a 20% increase over sea level values. The mini Wright flow meter gave readings 6% below sea level values for this altitude--that is, under-reading by 26%. Measurements of PEF made at altitude with the mini Wright meter should be corrected by adding 6.6% per 100 mm Hg drop in barometric pressure.

  3. High-altitude aerostats as astronomical platforms

    NASA Astrophysics Data System (ADS)

    Bely, Pierre Y.; Ashford, Robert; Cox, Charles D.

    1995-06-01

    The tropopause, typically at 16 to 18 km altitude at the lower latitudes, dips to 8 km in the polar regions. This makes the cold, dry, and nonturbulent lower stratosphere accessible to tethered aerostats. Tethered aerostats can fly as high as 12 km and are extremely reliable, lasting for many years. In contrast to free-flying balloons, they can stay on station for weeks at a time, and payloads can be safely recovered for maintenance and adjustment and relaunched in a matter of hours. We propose to use such a platform, located first in the Arctic (near Fairbanks, Alaska), and then later in the Antarctic, to operate a new technology 4-meter telescope with diffraction-limited performance in the near-IR. Thanks to the low ambient temperature (200 degrees K), thermal emission from the optics is of the same order as that of the zodiacal light in the 2 to 3 micron band. Since this wavelength interval is the darkest part of the zodiacal light spectrum from optical wavelengths to 100 microns, the combination of high resolution images and a very dark sky make it the spectral region of choice for observing the redshifted light from galaxies and clusters of galaxies at moderate to high redshifts.

  4. Collisional Effects in Simulations of High Altitude Nuclear Explosions

    NASA Astrophysics Data System (ADS)

    Islam, Tanim

    2013-10-01

    The simulation of the later-time (> 1 second) debris dynamics of a high altitude nuclear explosion (HANE) require, at a minimum, an understanding of the interaction of the ionized blast material with the relatively collisional upper ionosphere and lower exosphere (<= 200 km). At these altitudes, the collisional mean free path of ionized atmospheric particles may become smaller than the length scale of the diamagnetic bubble. Here we report on the local dynamics about the debris/air interface for Starfish Prime like, and lower energy, HANEs at altitudes in which collisionality becomes important. We model the debris dynamics with the hybrid plasma simulation code KIM3D, and use a standard Miller-Combi particle pairing algorithm to model particle collisions. We demonstrate new dynamics associated with finite collisionality in mildly collisional HANEs.

  5. Remote sensing of chlorophyll concentration from high altitude

    NASA Technical Reports Server (NTRS)

    Leung, K. C.; Hovis, W. A.

    1976-01-01

    A series of remote sensing experiments, using an airborne Ocean Color Scanner (OCS), has been carried out to demonstrate the feasibility of detecting surface chlorophyll concentrations in coastal water from high altitude. Upwelling radiance from the sea surface was recorded by 10 narrow bandwidth wavelength channels of the OCS, at an altitude of 19.8 km. Measurements were made over areas with vastly different biological activities. A strong correlation between the OCS radiance measurements and the surface chlorophyll measurements was found. The extracted chlorophyll signature agreed qualitatively with results from low altitude observations, except in the blue region. In addition, it was found that a simple algorithm could be used to estimate reliable chlorophyll distributions from OCS measurements.

  6. Altitude transitions in energy climbs

    NASA Technical Reports Server (NTRS)

    Weston, A. R.; Cliff, E. M.; Kelley, H. J.

    1982-01-01

    The aircraft energy-climb trajectory for configurations with a sharp transonic drag rise is well known to possess two branches in the altitude/Mach-number plane. Transition in altitude between the two branches occurs instantaneously, a 'corner' in the minimum-time solution obtained with the energy-state model. If the initial and final values of altitude do not lie on the energy-climb trajectory, then additional jumps (crude approximations to dives and zooms) are required at the initial and terminal points. With a singular-perturbation approach, a 'boundary-layer' correction is obtained for each altitude jump, the transonic jump being a so-called 'internal' boundary layer, different in character from the initial and terminal layers. The determination of this internal boundary layer is examined and some computational results for an example presented.

  7. Acute high-altitude sickness.

    PubMed

    Luks, Andrew M; Swenson, Erik R; Bärtsch, Peter

    2017-01-01

    At any point 1-5 days following ascent to altitudes ≥2500 m, individuals are at risk of developing one of three forms of acute altitude illness: acute mountain sickness, a syndrome of nonspecific symptoms including headache, lassitude, dizziness and nausea; high-altitude cerebral oedema, a potentially fatal illness characterised by ataxia, decreased consciousness and characteristic changes on magnetic resonance imaging; and high-altitude pulmonary oedema, a noncardiogenic form of pulmonary oedema resulting from excessive hypoxic pulmonary vasoconstriction which can be fatal if not recognised and treated promptly. This review provides detailed information about each of these important clinical entities. After reviewing the clinical features, epidemiology and current understanding of the pathophysiology of each disorder, we describe the current pharmacological and nonpharmacological approaches to the prevention and treatment of these diseases. Copyright ©ERS 2017.

  8. Stratospheric microbiology at 20 km over the Pacific Ocean

    USGS Publications Warehouse

    Smith, D.J.; Griffin, Dale W.; Schuerger, A.C.

    2010-01-01

    An aerobiology sampling flight at 20 km was conducted on 28 April 2008 over the Pacific Ocean (36.5° N, 118–149° W), a period of time that coincided with the movement of Asian dust across the ocean. The aim of this study was to confirm the presence of viable bacteria and fungi within a transoceanic, atmospheric bridge and to improve the resolution of flight hardware processing techniques. Isolates of the microbial strains recovered were analyzed with ribosomal ribonucleic acid (rRNA) sequencing to identify bacterial species Bacillus sp., Bacillus subtilis, Bacillus endophyticus, and the fungal genus Penicillium. Satellite imagery and ground-based radiosonde observations were used to measure dust movement and characterize the high-altitude environment at the time of collection. Considering the atmospheric residency time (7–10 days), the extreme temperature regime of the environment (-75°C), and the absence of a mechanism that could sustain particulates at high altitude, it is unlikely that our samples indicate a permanent, stratospheric ecosystem. However, the presence of viable fungi and bacteria in transoceanic stratosphere remains relevant to understanding the distribution and extent of microbial life on Earth.

  9. Stratospheric microbiology at 20 km over the Pacific Ocean

    USGS Publications Warehouse

    Smith, David J.; Griffin, Dale W.; Schuerger, Andrew C.

    2010-01-01

    An aerobiology sampling flight at 20 km was conducted on 28 April 2008 over the Pacific Ocean (36.5° N, 118–149° W), a period of time that coincided with the movement of Asian dust across the ocean. The aim of this study was to confirm the presence of viable bacteria and fungi within a transoceanic, atmospheric bridge and to improve the resolution of flight hardware processing techniques. Isolates of the microbial strains recovered were analyzed with ribosomal ribonucleic acid (rRNA) sequencing to identify bacterial species Bacillus sp., Bacillus subtilis, Bacillus endophyticus, and the fungal genus Penicillium. Satellite imagery and ground-based radiosonde observations were used to measure dust movement and characterize the high-altitude environment at the time of collection. Considering the atmospheric residency time (7–10 days), the extreme temperature regime of the environment (-75°C), and the absence of a mechanism that could sustain particulates at high altitude, it is unlikely that our samples indicate a permanent, stratospheric ecosystem. However, the presence of viable fungi and bacteria in transoceanic stratosphere remains relevant to understanding the distribution and extent of microbial life on Earth.

  10. Pure Rotational Raman Lidar for Temperature Measurements from 5-40 Km Over Wuhan, China

    NASA Astrophysics Data System (ADS)

    Li, Yajuan; Song, Shalei; Yang, Yong; Li, Faquan; Cheng, Xuewu; Chen, Zhenwei; Liu, Linmei; McCormick, M. Patrick; Gong, Shunsheng

    2016-06-01

    In this paper a pure rotational Raman lidar (PRR) was established for the atmospheric temperature measurements from 5 km to 40 km over Wuhan, China (30.5°N, 114.5°E). To extract the expected PRR signals and simultaneously suppress the elastically backscattered light, a high-spectral resolution polychromator for light splitting and filtering was designed. Observational results revealed that the temperature difference measured by PRR lidar and the local radiosonde below 30 km was less than 3.0 K. The good agreement validated the reliability of the PRR lidar. With the 1-h integration and 150-m spatial resolution, the statistical temperature error for PRR lidar increases from 0.4 K at 10 km up to 4 K at altitudes of about 30 km. In addition, the whole night temperature profiles were obtained for study of the long-term observation of atmospheric fluctuations.

  11. A3 Altitude Test Facility

    NASA Technical Reports Server (NTRS)

    Dulreix, Lionel J.

    2009-01-01

    This slide presentation shows drawings, diagrams and photographs of the A3 Altitude Test Facility. It includes a review of the A3 Facility requirements, and drawings of the various sections of the facility including Engine Deck and Superstructure, Test Cell and Thrust Takeout, Structure and Altitude Support Systems, Chemical Steam generators, and the subscale diffuser. There are also pictures of the construction site, and the facility under construction. A Diagram of the A3 Steam system schematic is also shown

  12. Psychological testing at high altitudes.

    PubMed

    Nelson, M

    1982-02-01

    Psychological testing was done on 20 subjects at various altitudes (sea level, 3,8,10 m, and 5,000 m) during a 35-d mountaineering expedition to Denali (Mt. McKinley). Intellectual functioning and personality changes were studied. While little variation was noted at the lower altitude, at 5,000 m there was a marked deterioration in cognitive ability. This was accompanied by a sharp increase in paranoia and obsessive-compulsiveness and smaller increases in depression and hostility.

  13. A Daytime Aspect Camera for Balloon Altitudes

    NASA Technical Reports Server (NTRS)

    Dietz, Kurt L.; Ramsey, Brian D.; Alexander, Cheryl D.; Apple, Jeff A.; Ghosh, Kajal K.; Swift, Wesley R.; Six, N. Frank (Technical Monitor)

    2001-01-01

    We have designed, built, and flight-tested a new star camera for daytime guiding of pointed balloon-borne experiments at altitudes around 40km. The camera and lens are commercially available, off-the-shelf components, but require a custom-built baffle to reduce stray light, especially near the sunlit limb of the balloon. This new camera, which operates in the 600-1000 nm region of the spectrum, successfully provided daytime aspect information of approximately 10 arcsecond resolution for two distinct star fields near the galactic plane. The detected scattered-light backgrounds show good agreement with the Air Force MODTRAN models, but the daytime stellar magnitude limit was lower than expected due to dispersion of red light by the lens. Replacing the commercial lens with a custom-built lens should allow the system to track stars in any arbitrary area of the sky during the daytime.

  14. Daytime Aspect Camera for Balloon Altitudes

    NASA Technical Reports Server (NTRS)

    Dietz, Kurt L.; Ramsey, Brian D.; Alexander, Cheryl D.; Apple, Jeff A.; Ghosh, Kajal K.; Swift, Wesley R.

    2002-01-01

    We have designed, built, and flight-tested a new star camera for daytime guiding of pointed balloon-borne experiments at altitudes around 40 km. The camera and lens are commercially available, off-the-shelf components, but require a custom-built baffle to reduce stray light, especially near the sunlit limb of the balloon. This new camera, which operates in the 600- to 1000-nm region of the spectrum, successfully provides daytime aspect information of approx. 10 arcsec resolution for two distinct star fields near the galactic plane. The detected scattered-light backgrounds show good agreement with the Air Force MODTRAN models used to design the camera, but the daytime stellar magnitude limit was lower than expected due to longitudinal chromatic aberration in the lens. Replacing the commercial lens with a custom-built lens should allow the system to track stars in any arbitrary area of the sky during the daytime.

  15. A challenge to the highest balloon altitude

    NASA Astrophysics Data System (ADS)

    Saito, Y.; Akita, D.; Fuke, H.; Iijima, I.; Izutsu, N.; Kato, Y.; Kawada, J.; Matsuzaka, Y.; Mizuta, E.; Namiki, M.; Nonaka, N.; Ohta, S.; Sato, T.; Seo, M.; Takada, A.; Tamura, K.; Toriumi, M.; Yamagami, T.; Yamada, K.; Yoshida, T.; Matsushima, K.; Tanaka, S.

    2012-02-01

    Development of a balloon to fly at higher altitudes is one of the most attractive challenges for scientific balloon technologies. After reaching the highest balloon altitude of 53.0 km using the 3.4 μm film in 2002, a thinner balloon film with a thickness of 2.8 μm was developed. A 5000 m3 balloon made with this film was launched successfully in 2004. However, three 60,000 m3 balloons with the same film launched in 2005, 2006, and 2007, failed during ascent. The mechanical properties of the 2.8 μm film were investigated intensively to look for degradation of the ultimate strength and its elongation as compared to the other thicker balloon films. The requirement of the balloon film was also studied using an empirical and a physical model assuming an axis-symmetrical balloon shape and the static pressure. It was found that the film was strong enough. A stress due to the dynamic pressure by the wind shear is considered as the possible reason for the unsuccessful flights. A 80,000 m3 balloon with cap films covering 9 m from the balloon top will be launch in 2011 to test the appropriateness of this reinforcement.

  16. The Gravity Field of Mercury After the Messenger Low-Altitude Campaign

    NASA Technical Reports Server (NTRS)

    Mazarico, Erwan; Genova, Antonio; Goossens, Sander; Lemoine, Frank G.; Smith, David E.; Zuber, Maria T.; Neumann, Gary A.; Solomon, Sean C.

    2015-01-01

    The final year of the MESSENGER mission was designed to take advantage of the remaining propellant onboard to provide a series of lowaltitude observation campaigns and acquire novel scientific data about the innermost planet. The lower periapsis altitude greatly enhances the sensitivity to the short-wavelength gravity field, but only when the spacecraft is in view of Earth. After more than 3 years in orbit around Mercury, the MESSENGER spacecraft was tracked for the first time below 200-km altitude on 5 May 2014 by the NASA Deep Space Network (DSN). Between August and October, periapsis passages down to 25-km altitude were routinely tracked. These periods considerably improved the quality of the data coverage. Before the end of its mission, MESSENGER will fly at very low altitudes for extended periods of time. Given the orbital geometry, however the periapses will not be visible from Earth and so no new tracking data will be available for altitudes lower than 75 km. Nevertheless, the continuous tracking of MESSENGER in the northern hemisphere will help improve the uniformity of the spatial coverage at altitudes lower than 150 km, which will further improve the overall quality of the Mercury gravity field.

  17. Spectral analysis of the multiple-altitude anomalous geomagnetic field

    NASA Astrophysics Data System (ADS)

    Tsvetkov, Yu. P.; Ivanov, V. V.; Petrov, V. G.; Filippov, S. V.; Brekhov, O. M.

    2016-11-01

    The spectra of the anomalous geomagnetic field measured at ground and balloon (30 km) altitudes were analyzed. The ground-based data were adapted from a map of the anomalous magnetic field of the Earth. A balloon surveys was carried out by the authors. It has been shown that the ground and balloon spectra of the anomalous magnetic field of the Earth substantially differ. Suppositions explaining the differences in the obtained spectra have been suggested.

  18. Altitude illness in Qinghai–Tibet railroad passengers.

    PubMed

    Wu, Tian Yi; Ding, Shou Quan; Zhang, Sheng Lin; Duan, Jin Qing; Li, Bao Yu; Zhan, Zhong Yan; Wu, Qin Li; Baomu, Suolung; Liang, Bao Zhu; Han, Shu Rang; Jie, Yu Ling; Li, Gang; Sun, Lin; Kayser, Bengt

    2010-01-01

    It takes ≈24 h to travel the ≈3000-km-long Qinghai–Tibet railroad of which 85% is situated above 4000 m with a pass at 5072 m. Each year about 2 million passengers are rapidly exposed to high altitude traveling on this train. The aim of this study was to quantify the occurrence of altitude illness on the train. Three subject groups were surveyed: 160 Han lowlanders, 62 Han immigrants living at 2200 to 2500 m, and 25 Tibetans living at 3700 to 4200 m. Passengers reached 4768 m from 2808 m in less than 1.5 h, after which 78% of the passengers reported symptoms, 24% reaching the Lake Louise criterion score for AMS. AMS incidence was 31% in nonacclimatized Han compared to 16% in Han altitude residents and 0% in Tibetans. Women and older subjects had a slightly greater risk for AMS. Most cases of AMS were mild and self-limiting, resolving within days upon arrival in Lhasa. Some cases of more severe AMS necessitated medical attention. To curb the health risk of rapid travel to altitude by train, prospective travelers should be better informed, medical train personnel should be well trained, and staged travel with 1 to 2 days at intermediate altitudes should be suggested to nonacclimatized subjects.

  19. A method for sampling microbial aerosols using high altitude balloons.

    PubMed

    Bryan, N C; Stewart, M; Granger, D; Guzik, T G; Christner, B C

    2014-12-01

    Owing to the challenges posed to microbial aerosol sampling at high altitudes, very little is known about the abundance, diversity, and extent of microbial taxa in the Earth-atmosphere system. To directly address this knowledge gap, we designed, constructed, and tested a system that passively samples aerosols during ascent through the atmosphere while tethered to a helium-filled latex sounding balloon. The sampling payload is ~ 2.7 kg and comprised of an electronics box and three sampling chambers (one serving as a procedural control). Each chamber is sealed with retractable doors that can be commanded to open and close at designated altitudes. The payload is deployed together with radio beacons that transmit GPS coordinates (latitude, longitude and altitude) in real time for tracking and recovery. A cut mechanism separates the payload string from the balloon at any desired altitude, returning all equipment safely to the ground on a parachute. When the chambers are opened, aerosol sampling is performed using the Rotorod® collection method (40 rods per chamber), with each rod passing through 0.035 m3 per km of altitude sampled. Based on quality control measurements, the collection of ~ 100 cells rod(-1) provided a 3-sigma confidence level of detection. The payload system described can be mated with any type of balloon platform and provides a tool for characterizing the vertical distribution of microorganisms in the troposphere and stratosphere. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Altitude is positively correlated to race time during the marathon.

    PubMed

    Lara, Beatriz; Salinero, Juan José; Del Coso, Juan

    2014-04-01

    Completing a marathon (42.2 km) is one of the more challenging sports activities. Besides the distance, the ambient conditions of the race (altitude, temperature, etc) can increase the physiological demands of the event. The purpose of this study was to investigate the relation between the altitude of the city in which the marathon is held and the marathon race time. For this purpose, we sought the race times of 16 popular marathons performed at different altitudes above sea level (range from ≈0 to 2800 meters above sea level). In these competitions, we analyzed the race times of the female and male runners who finished from 21(st) to 100(th) position. We excluded the top 20 male and female finishers from the analysis because elite athletes usually compete in marathons held at low altitudes above sea level. Ambient temperature, the positive cumulative elevation gain, and the number of participants were used as control variables. Finishing time in the marathon was positively correlated with the altitude of the competition for both male (r=0.78; p<0.05) and female participants (r=0.73; p<0.05). On average, each increase of 1000 meters above sea level augmented marathon race time by 10.8±0.6% in men and 12.3±0.7% in women. Compared to race times in the Rotterdam marathon (held at 0 meters above sea level), the time taken to complete the marathon was significantly higher in competitions held at an altitude of over 700 meters. In conclusion, the time taken to complete a marathon strongly depends on the altitude of the city in which the marathon is held. Selecting marathon competitions close to 0 m above sea level is a good strategy to maximize marathon performance.

  1. The Mercury Gravity Field after the MESSENGER Low-Altitude Gravity Campaign

    NASA Astrophysics Data System (ADS)

    Mazarico, E.; Genova, A.; Goossens, S. J.; Lemoine, F. G.; Neumann, G. A.; Smith, D. E.; Zuber, M. T.; Solomon, S. C.

    2014-12-01

    NASA's MESSENGER spacecraft has collected more than 3.5 years of X-band radio tracking data in orbit around the planet Mercury. During its one-year primary mission, which started in March 2011, MESSENGER was in an eccentric, near-polar orbit of 12-hour period, and the periapsis altitude was actively maintained between 200 and 500 km. For its extended mission, the orbit period was reduced to 8 hours. As the orbit naturally evolved, in large part due to the third-body gravitational perturbation of the Sun, the periapsis altitude reached a maximum of ~450 km in March 2013 and then began to decrease. An ambitious end of mission was designed to use the remaining fuel to delay impact and to observe the northern hemisphere for nearly a year at periapsis altitudes lower than 200 km, including four intervals of exceptionally low altitude (25-100 km). Periapsis passages are visible from Earth only for two of these intervals, in August and October 2014. These new data, the lowest-altitude radio tracking measurements to be acquired by MESSENGER, prompt an updated solution for the gravity field of Mercury. In preparation for acquisition of the low-altitude (<100 km) data, we have reprocessed tracking data through 14 July 2014. These data already provide good coverage below 200 km over most longitudes. A preliminary gravity solution to degree and order 50 shows stronger gravity anomalies near the periapsis latitudes than in the most recent global solution, HgM005. To best capture the shorter-wavelength signals expected from the lowest-altitude passes, we are estimating a large number of local surface anomalies (arranged on a 1°x1° grid) in addition to a harmonic field. We are also using the resulting gravity anomalies to update crustal thickness models and to explore the implications for gravity anomalies over basins and topographic rises and the modes of compensation of these features.

  2. Certification and safety aspects relating to the transport of passengers on high altitude balloons in Europe

    NASA Astrophysics Data System (ADS)

    Schoenmaker, Annelie

    2014-07-01

    High-altitude balloons typically fly between 25 and 50 km in altitude, which, while below the Karman line of 100 km, is yet far above the altitudes typically flown by aircraft. For example, the highest-flying commercial aircraft - the Concorde - had a maximum cruising altitude of only 18 km. zero2infinity, a Spanish company, is currently developing a pressurized pod named “bloon” which will be capable of lifting six people, including two pilot crew members and four paying passengers, to an altitude of 36 km through the use of high-altitude balloons. The boundary between Airspace and Outer Space has never been legally defined, mostly because of the lack of activities taking place between the altitude where airplanes fly and the lowest orbiting spacecraft. High-altitude balloons do fly at these in-between altitudes and the prospect of commercializing access to these parts of the stratosphere poses some questions in a new light. Given the relatively low altitude at which they fly, it may well be that these types of balloons would be considered to operate exclusively within air space. However, given the technology involved in crewed high altitude balloon flights, which is more similar to spacecraft engineering than to traditional hot-air or gas ballooning, it is necessary to evaluate the various legal regimes, codes, and regulations that would apply to such flights, especially regarding licenses and liabilities. For high altitude balloon flights commencing in Europe, the European Aviation Safety Agency (EASA) would very likely be the competent certification or licensing agency for these flights, although there would likely be input from various national aviation authorities as well. However, because the European Commission (EC) has not yet issued regulations regarding commercial spaceflight, particularly the use of high altitude balloons, new rules and regulations governing such flights may still need to be drafted and promulgated. With the development of

  3. Asteroid airburst altitude vs. strength

    NASA Astrophysics Data System (ADS)

    Robertson, Darrel; Wheeler, Lorien; Mathias, Donovan

    2016-10-01

    Small NEO asteroids (<Ø140m) may not be a threat on a national or global level but can still cause a significant amount of local damage as demonstrated by the Chelyabinsk event where there was over $33 million worth of damage (1 billion roubles) and 1500 were injured, mostly due to broken glass. The ground damage from a small asteroid depends strongly on the altitude at which they "burst" where most of the energy is deposited in the atmosphere. The ability to accurately predict ground damage is useful in determining appropriate evacuation or shelter plans and emergency management.Strong asteroids, such as a monolithic boulder, fail and create peak energy deposition close to the altitude at which ram dynamic pressure exceeds the material cohesive strength. Weaker asteroids, such as a rubble pile, structurally fail at higher altitude, but it requires the increased aerodynamic pressure at lower altitude to disrupt and disperse the rubble. Consequently the resulting airbursts have a peak energy deposition at similar altitudes.In this study hydrocode simulations of the entry and break-up of small asteroids were performed to examine the effect of strength, size, composition, entry angle, and speed on the resulting airburst. This presentation will show movies of the simulations, the results of peak burst height, and the comparison to semi-analytical models.

  4. Asteroid airburst altitude vs. strength

    NASA Astrophysics Data System (ADS)

    Robertson, D. K.; Wheeler, L.; Mathias, D.

    2016-12-01

    The entry and break-up of small asteroids were simulated with a hydrocode to examine the effect of strength, size, composition, entry angle, and speed on the resulting airburst. A strong asteroid, such as a monolithic boulder, structurally fail and deposit most of their energy around the altitude at which dynamic ram pressure exceeds the cohesive strength of the asteroid. A weaker asteroid, such as a loose rubble pile, will structurally fail at high altitude, but continue to fly through the atmosphere as a single unit until reaching lower altitudes where the increased aerodynamic pressure is sufficient to disrupt and disperse the rubble resulting in a flare. Airburst from weak asteroids consequently have a peak energy deposition at similar altitudes.This study focuses on small NEO asteroids which are likely to airburst rather than impact the ground where the damage created on the ground depends strongly on the altitude at which most of the energy is deposited in the atmosphere. The ability to accurately predict ground damage is useful in determining appropriate evacuation or shelter plans and emergency management. Airbursting asteroids are not a threat on a national level but can still cause a significant amount of local damage as demonstrated by the Chelyabinsk event where there was over $33 million worth of damage (1 billion roubles) and 1500 were injured by flying glass.

  5. Frustrated exchange interactions formation at low temperatures and high hydrostatic pressures in La{sub 0.70}Sr{sub 0.30}Mn{sub O2.85}

    SciTech Connect

    Trukhanov, S. V. Trukhanov, A. V.; Vasiliev, A. N.; Szymczak, H.

    2010-08-15

    The magnetic and thermal properties of the anion-deficient La{sub 0.70}Sr{sub 0.30}MnO{sub 2.85} manganite are investigated in wide temperature (4-350 K) range, including under hydrostatic pressure (0-1.1 GPa). Throughout the pressure range investigated, the sample is spin glass with diffused phase transition into paramagnetic state. It is established, that spin glass state is a consequence of exchange interaction frustration of the ferromagnetic clusters embeded into antiferromagnetic clusters. The magnetic moment freezing temperature T{sub f} of ferromagnetic clusters increases under pressure, freezing temperature dependence on pressure is characterized by derivative value {approx}4.5 K/GPa, while the magnetic ordering T{sub MO} temperature dependence is characterized by derivative value {approx}13 K/GPa. The volume fraction of sample having ferromagnetic state is V{sub fer} {approx} 13% and it increases under a pressure of 1.1 GPa by {Delta}V{sub fer} {approx} 6%. Intensification of ferromagnetic properties of the anion-deficient La{sub 0.70}Sr{sub 0.30}MnO{sub 2.85} manganite under hydrostatic pressure is a consequence of oxygen vacancies redistribution and unit cell parameters decrease. The most likely mechanism of frustrated exchange interactions formation is discussed.

  6. Magnetic state of the structural separated anion-deficient La{sub 0.70}Sr{sub 0.30}MnO{sub 2.85} manganite

    SciTech Connect

    Trukhanov, S. V. Trukhanov, A. V.; Vasiliev, A. N.; Balagurov, A. M.; Szymczak, H.

    2011-11-15

    The results of neutron diffraction studies of the La{sub 0.70}Sr{sub 0.30}MnO{sub 2.85} compound and its behavior in an external magnetic field are stated. It is established that in the 4-300 K temperature range, two structural perovskite phases coexist in the sample, which differ in symmetry (groups R3-bar c and I4/mcm). The reason for the phase separation is the clustering of oxygen vacancies. The temperature (4-300 K) and field (0-140 kOe) dependences of the specific magnetic moment are measured. It is found that in zero external field, the magnetic state of La{sub 0.70}Sr{sub 0.30}MnO{sub 2.85} is a cluster spin glass, which is the result of frustration of Mn{sup 3+}-O-Mn{sup 3+} exchange interactions. An increase in external magnetic field up to 10 kOe leads to fragmentation of ferromagnetic clusters and then to an increase in the degree of polarization of local spins of manganese and the emergence of long-range ferromagnetic order. With increasing magnetic field up to 140 kOe, the magnetic ordering temperature reaches 160 K. The causes of the structural and magnetic phase separation of this composition and formation mechanism of its spin-glass magnetic state are analyzed.

  7. Source altitudes of terrestrial gamma-ray flashes produced by lightning leaders

    NASA Astrophysics Data System (ADS)

    Xu, Wei; Celestin, Sebastien; Pasko, Victor P.

    2012-04-01

    Terrestrial gamma-ray flashes (TGFs) are energetic photon bursts observed from satellites and associated with lightning activity. Comparison between calculations based on the model of relativistic runaway electron avalanches (RREA) in large-scale weak electric field in thunderstorms and satellite measurements usually shows that the photon spectrum is consistent with source altitudes around 15 km. However, recent observations have located intra-cloud lightning (IC) discharges responsible for TGFs much deeper in the atmosphere (at altitudes ˜10 km). In the present work, we show that the TGF spectrum as produced by acceleration of electrons in the strong electric field of stepping IC leaders is consistent with the lower altitudes recently discovered. This study reconciles observations and measurements by setting new altitudes for the TGF sources based on mechanism of direct acceleration of electrons in the lightning leader field. Moreover, the photon source beaming geometry is consistently determined from the geometry of electric field lines produced by the lightning leader.

  8. Dependence of Venus ionopause altitude and ionospheric magnetic field on solar wind dynamic pressure

    NASA Technical Reports Server (NTRS)

    Phillips, J. L.; Luhmann, J. G.; Russell, C. T.

    1985-01-01

    The shape of the dayside Venus ionopause, and its dependence on solar wind parameters, is examined using Pioneer Venus Orbiter field and particle data. The ionopause is defined here as the altitude of pressure equality between magnetosheath pressure and ionospheric thermal pressure; its typical altitudes range from about 300 km near the subsolar point to about 900 km near the terminator. A strong correlation between ionopause altitude and magnetosheath magnetic pressure is demonstrated; correlation between magnetic pressure and the normally incident component of solar wind dynamic pressure is also evident. The data support the hypothesis of control of the ionopause altitude by solar wind dynamic pressure, manifested in the sheath as magnetic pressure. The presence of large scale magnetic fields in the ionosphere is observed primarily when dynamic pressure is high and the ionopause is low.

  9. Dependence of field-aligned electron precipitation occurrence on season and altitude

    NASA Technical Reports Server (NTRS)

    Berko, F. W.; Hoffman, R. A.

    1974-01-01

    An examination of factors affecting the occurrence of field-aligned 2.3-keV electron precipitation has been performed by using data from more than 7500 orbits of the polar-orbiting satellite Ogo 4. Both season and altitude were found to be parameters that are directly related to the probability of occurrence. The highest probabilities occurred when the measurements were made at altitudes from 800 km to apogee (914 km), except during summer. In this altitude interval, the electron precipitation was more likely to be field-aligned during winter than during any other season. The analysis suggests the establishment by electrostatic charge layers of localized electric fields parallel to the magnetic field. The resulting potential distribution focuses the electron beam along the field lines in the region between the charge layers but destroys the focused beam below the lower layer, and thus an altitude dependence is created.

  10. The effect of ski training at altitude and racing on pituitary, adrenal and testicular function in men.

    PubMed

    Vasankari, T J; Rusko, H; Kujala, U M; Huhtaniemi, I T

    1993-01-01

    The effect of similar prolonged exercise on hormonal changes was studied at sea level and at moderate altitude. Four cross-country skiers participated in a 30-km race and five biathlonists in a 20-km race at sea level in Finland and during altitude training and racing at 1650 m in Les Saisies, France. Venous blood samples were taken at both altitudes before the race between 0800 and 0900 hours and 25-35 min after the race. Resting blood samples were also taken before and after the altitude training and the period of racing. Serum testosterone concentration was higher before the race at altitude than at sea level (19%, P < 0.02), and 30 min after the race growth hormone (GH) concentration was higher at sea level than at moderate altitude (P < 0.002). There were not significant differences in serum luteinising hormone between the altitudes. Serum cortisol concentration was higher after the altitude training and the period of racing than before (P < 0.02) but no difference was observed in testosterone. We concluded, that since the profiles of the anabolic-catabolic hormone concentrations measured are indicators of the performance level of athletes, our data indicated that to follow them during altitude training could be beneficial in optimizing training programme for individual athletes. We also concluded, that the lower GH concentration after racing at moderate altitude may have been a consequence of decreased racing speed and/or increased physical performance.

  11. Travelling safely to places at high altitude - Understanding and preventing altitude illness.

    PubMed

    Parise, Ivan

    2017-06-01

    Greater numbers of people are travelling to places at high altitude each year. Altitude illness is common in places at high altitude and may be life-threatening. General practitioners (GPs) are best placed to provide evidence-based advice to keep travellers well informed of the possible risks they may encounter in places at high altitude. The aim of this article is to review knowledge on altitude illness in order to help GPs assist patients to travel safely to places at high altitude. Acclimatisation to high altitude is a complex process and when inadequate leads to the pathological changes of altitude illness, including high-altitude headache, cerebral oedema, pulmonary oedema and acute mountain sickness. Higher ascent, faster rate of ascent and a previous history of altitude illness increase the risk of altitude illness. Acetazolamide and other medications used to prevent altitude illness are discussed in detail, including the finding that inhaled budesonide may prevent altitude illness.

  12. CO2 LIDAR measurements over a 20-km slant path

    NASA Astrophysics Data System (ADS)

    Senft, Daniel C.; Fox, Marsha J.; Gonglewski, John D.; Dowling, James A.; Highland, Ronald G.; Shilko, Michael L.

    1997-01-01

    The Air Force Phillips Laboratory conducted a series of measurements in February, May and August 1995 at the Air Force Maui Optical Station (AMOS) facility on Maui, Hawaii, to determine system requirements for an airborne long path CO(subscript 2) DIAL system. The lidar incorporates a cavity-matched mode-locked 3-J laser with the 60 cm diameter AMOS Beam Director Telescope. The one-way beam propagation path length was 21.3 km, originating at the AMOS facility on Haleakala at an altitude of 3.050 km ASL, and terminating at a target site near sea level. Both heterodyne and direct detection techniques are compared with respect to radiometric performance and signal statistics. Minimum detectable absorption levels for DIAL systems using both detection techniques and a variety of targets are estimated from long- range measurements with controlled absorbers. The signal correlation as a function of interpulse temporal separation was determined for long-range direct detection measurements. Radiometric models including system optical characteristics, beam propagation considerations, target reflectivity characteristics,a nd atmospheric effects have been developed and validated experimentally. A new receiver system is currently being fabricated and the laser transmitter is being upgraded for pulse-to-pulse wavelength agility, prior to incorporation into a C-135E airborne platform for future flight experiments.

  13. Solar collector with altitude tracking

    DOEpatents

    Barak, Amitzur Z.

    1977-01-01

    A device is provided for turning a solar collector about an east-west horizontal axis so that the collector is tilted toward the sun as the EWV altitude of the sun varies each day. It includes one or more heat responsive elements and a shading means aligned so that within a range of EWV altitudes of the sun during daylight hours the shading means shades the element or elements while during the rest of the daylight hours the elements or elements are heated by the sun to assume heated, stable states. Mechanical linkage between the collector and the element is responsive to the states of the element or elements to tilt the collector in accordance with variations in the EWV altitude of the sun.

  14. Lightweight Liquid Helium Dewar for High-Altitude Balloon Payloads

    NASA Technical Reports Server (NTRS)

    Kogut, Alan; James, Bryan; Fixsen, Dale

    2013-01-01

    Astrophysical observations at millimeter wavelengths require large (2-to-5- meter diameter) telescopes carried to altitudes above 35 km by scientific research balloons. The scientific performance is greatly enhanced if the telescope is cooled to temperatures below 10 K with no emissive windows between the telescope and the sky. Standard liquid helium bucket dewars can contain a suitable telescope for telescope diameter less than two meters. However, the mass of a dewar large enough to hold a 3-to-5-meter diameter telescope would exceed the balloon lift capacity. The solution is to separate the functions of cryogen storage and in-flight thermal isolation, utilizing the unique physical conditions at balloon altitudes. Conventional dewars are launched cold: the vacuum walls necessary for thermal isolation must also withstand the pressure gradient at sea level and are correspondingly thick and heavy. The pressure at 40 km is less than 0.3% of sea level: a dewar designed for use only at 40 km can use ultra thin walls to achieve significant reductions in mass. This innovation concerns new construction and operational techniques to produce a lightweight liquid helium bucket dewar. The dewar is intended for use on high-altitude balloon payloads. The mass is low enough to allow a large (3-to-5-meter) diameter dewar to fly at altitudes above 35 km on conventional scientific research balloons without exceeding the lift capability of the balloon. The lightweight dewar has thin (250- micron) stainless steel walls. The walls are too thin to support the pressure gradient at sea level: the dewar launches warm with the vacuum space vented continuously during ascent to eliminate any pressure gradient across the walls. A commercial 500-liter storage dewar maintains a reservoir of liquid helium within a minimal (hence low mass) volume. Once a 40-km altitude is reached, the valve venting the vacuum space of the bucket dewar is closed to seal the vacuum space. A vacuum pump then

  15. The altitude of type 3 auroral irregularities - Radar interferometer observations and implications

    NASA Astrophysics Data System (ADS)

    Sahr, J. D.; Farley, D. T.; Swartz, W. E.; Providakes, J. F.

    1991-10-01

    Altitude measurements are presented of type 3 auroral irregularities, acquired in northern Scandinavia in March 1989 during the second E Region Rocket Radar Instability Study campaign, that provide conclusive arguments against the electrostatic ion cyclotron instability theory. Interferometric analyses of coherent radar observations with a portable radar interferometer show that type 3 events occur at typical electrojet altitudes (100-120 km), at which the ion collision frequency is greater than the ion gyrofrequency, and no cyclotron motion is possible.

  16. Design concepts for the first 40 km a key step for the space elevator

    NASA Astrophysics Data System (ADS)

    Knapman, John M.; Swan, Peter A.

    2014-11-01

    The Marine Node for the Space Elevator Infrastructure is the base for all activities to load and unload the cargo and climbers. As the basic design of the space elevator power system is solar power only, the first 40 km is hazardous to operations and demands enclosed packaging of fragile tether climbers. A significant question is: how do we place a full-up tether climber, driven by solar power, above the atmosphere? Two approaches, starting at the Marine Node, allow the tether climber to initiate the climb with solar energy above the atmosphere. The third viable approach is to provide a platform at altitude for initiation of tether climb. These approaches would enable solar power to be the source of energy for climbing. The three approaches are: Option One and Two: Marine Node (MN) Starting Location. MN - Box Protection - use boxes to protect the fragile solar panel and power the climber directly with a power extension cord to climb out of the atmosphere. MN - Spring Forward - use the characteristics of the elastic factor of the tether material. Option Three: High Stage One-develop a platform at altitude. Dangers for the space elevator during the first 40 km in altitude are discussed, and the options to deploy the tether climber and its solar arrays from the ocean surface to the desired altitude are explained.

  17. Return to Activity at Altitude After High-Altitude Illness

    PubMed Central

    DeWeber, Kevin; Scorza, Keith

    2010-01-01

    Context: Sports and other activities at high altitude are popular, yet they pose the unique risk for high-altitude illness (HAI). Once those who have suffered from a HAI recover, they commonly desire or need to perform the same activity at altitude in the immediate or distant future. Evidence Acquisition: As based on key text references and peer-reviewed journal articles from a Medline search, this article reviews the pathophysiology and general treatment principles of HAI. Results: In addition to the type of HAI experienced and the current level of recovery, factors needing consideration in the return-to-play plan include physical activity requirements, flexibility of the activity schedule, and available medical equipment and facilities. Most important, adherence to prudent acclimatization protocols and gradual ascent recommendations (when above 3000 m, no more than 600-m net elevation gain per day, and 1 rest day every 1 to 2 ascent days) is powerful in its preventive value and thus strongly recommended. When these are not practical, prophylactic medications (acetazolamide, dexamethasone, salmeterol, nifedipine, or phosphodiesterase inhibitors, depending on the type of prior HAI) may be prescribed and can reduce the risk of illness. Athletes with HAI should be counseled that physical and mental performance may be adversely affected if activity at altitude continues before recovery is complete and that there is a risk of progression to a more serious HAI. Conclusion: With a thoughtful plan, most recurrent HAI in athletes can be prevented. PMID:23015950

  18. Cognitive function at high altitude.

    PubMed

    Kramer, A F; Coyne, J T; Strayer, D L

    1993-06-01

    The effects of altitude on human performance and cognition were evaluated in a field study performed on Mount Denali in Alaska during the summer of 1990. Climbers performed a series of perceptual, cognitive, and sensory-motor tasks before, during, and after climbing the West Buttress route on Denali. Relative to a matched control group that performed the tasks at sea level, the climbers showed deficits of learning and retention in perceptual and memory tasks. Furthermore, climbers performed more slowly on most tasks than did the control group, suggesting long-term deficits that may be attributed to repeated forays to high altitudes.

  19. Addition of a low altitude Tethys flyby to the nominal Cassini tour

    NASA Technical Reports Server (NTRS)

    Buffington, Brent; Strange, Nathan; Ionasescu, Rodica

    2005-01-01

    Of the eight Saturnian icy satellites. all but Mimas and Tethys had low altitude targeted flybys during the 4-year primary Cassini spacecraft tour. In November 2004, the existence of a potential low-altitude Tethys flyby was discovered; this low-altitude flyby, added to the nominal tour in March 2005, corresponded to a 1500 km non-targeted periapsis altitude on September 24, 2005 with an associated (delta)v cost of approximately 8 mis. This memo details the methods used to determine the Rev-15 non-targeted Tethys flyby altitude, driven by navigational requirements and operational constraints, in addition to several trajectory modifications implemented to reduce total (delta)v costs, and in some cases. render simultaneous increases in scientific return.

  20. News from KM3NeT

    SciTech Connect

    Katz, Ulrich F.; Collaboration: KM3NeT Collaboration

    2014-11-18

    KM3NeT is a future research infrastructure in the Mediterranean Sea, hosting a multi-cubic-kilometre neutrino telescope and nodes for Earth and Sea sciences. In this report we shortly summarise the genesis of the KM3NeT project and present key elements of its technical design. The physics objectives of the KM3NeT neutrino telescope and some selected sensitivity estimates are discussed. Finally, some first results from prototype operations and the next steps towards implementation – in particular the first construction phase in 2014/15 – are described.

  1. Ataxia: an early indicator in high altitude cerebral edema.

    PubMed

    Wu, Tianyi; Ding, Shouquan; Liu, Jinliang; Jia, Jianhou; Dai, Ruichen; Liang, Baozhu; Zhao, Jizhui; Qi, Detang

    2006-01-01

    Wu, Tianyi, Shouquan Ding, Jinliang Liu, Jianhou Jia, Ruichen Dai, Baozhu Liang, Jizhui Zhao, and Detang Qi. Ataxia: an early indicator in high altitude cerebral edema. High Alt. Med. Biol. 7:275-280, 2006.--As a result of industrial development in the western region of China, in 2001 the Chinese government decided to build Qinghai-Tibetan Railway. The new railroad stretches 1118 km from Golmud (2808 m) to Lhasa (3658 m), with more than three-quarter of the distance above 4000 m, through the Mt. Kun Lun and Tanggula ranges. From the beginning of the project on June, 29, 2001, to the end of the year of 2003, about 74,735 construction workers worked in the harsh climate, in adverse circumstances and a low-barometric-pressure environment. The construction provided an opportunity for the investigation and study of acute mountain sickness (AMS), high altitude pulmonary edema (HAPE), and high altitude cerebral edema (HACE). These altitude illnesses were very common in the construction workers. From July 1, 2001, to October 31, 2003, the overall incidence of AMS, HAPE, and HACE in the total workers was approximately 45%-95%, 0.49%, and 0.26%, respectively. Altitude illnesses were studied at two hospitals near the construction site. One hospital is located on the Fenghuoshan (Mt. Wind-gap) at an altitude of 4779 m (PB 428 torr), and the second hospital is situated in the Kekexili area at an altitude of 4505 m (PB 440 torr). Kekexili is a sparsely populated zone because the weather conditions are very bad all year round. These two hospitals received patients from the construction sites, where workers were working at altitudes between 4464 and 4905 m. A total of 8014 workers were treated at Fenghuoshan and 5488 were in Kekexili over the past 3 years. According to local guidance about proper medical care, workers ascending to high altitude should be examined physically, complete an AMS questionnaire, and be monitored for ataxia as an early warning sign of the impending, more

  2. Production altitude and time delays of the terrestrial gamma flashes: Revisiting the Burst and Transient Source Experiment spectra

    NASA Astrophysics Data System (ADS)

    Østgaard, N.; Gjesteland, T.; Stadsnes, J.; Connell, P. H.; Carlson, B.

    2008-02-01

    On the basis of the RHESSI results it has been suggested that terrestrial gamma flashes (TGFs) are produced at very low altitudes. On the other hand some of the Burst and Transient Source Experiment (BATSE) spectra show unabsorbed fluxes of X rays in the 25-50 keV energy range, indicating a higher production altitude. To investigate this, we have developed a Monte Carlo code for X-ray propagation through the atmosphere. The most important features seen in the modeled spectra are (1) a low-energy cutoff which moves to lower energies as TGFs are produced at higher altitudes, (2) a high-energy cutoff which moves to lower energies as TGFs are observed at larger zenith angles, and (3) time delays are observed for TGFs produced at <=20 km (and some at 30 km) altitude when observed at larger zenith angle than the half-angle defining the initial isotropic X-ray beam. This is a pure Compton effect. The model results and an optimization procedure are used to estimate production altitudes of the BATSE TGFs. The main findings are (1) half or more of the BATSE TGFs are produced at low altitudes, <=20 km, (2) a significant portion of the BATSE TGFs are produced at higher altitudes, 30 km to 40 km, (3) for the TGFs produced at <=20 km (and some at 30 km) altitudes the dispersion signatures can be explained as a pure Compton effect, and (4) the softening of the BATSE spectra for increasing zenith angles and the time dispersions both indicate that the initial TGF distribution is beamed.

  3. Altitude preexposure recommendations for inducing acclimatization.

    PubMed

    Muza, Stephen R; Beidleman, Beth A; Fulco, Charles S

    2010-01-01

    For many low-altitude (<1500 m) residents, their travel itineraries may cause them to ascend rapidly to high (>2400 m) altitudes without having the time to develop an adequate degree of altitude acclimatization. Prior to departing on these trips, low-altitude residents can induce some degree of altitude acclimatization by ascending to moderate (>1500 m) or high altitudes during either continuous or intermittent altitude preexposures. Generally, the degree of altitude acclimatization developed is proportional to the altitude attained and the duration of exposure. The available evidence suggests that continuous residence at 2200 m or higher for 1 to 2 days or daily 1.5- to 4-h exposures to >4000 m induce ventilatory acclimatization. Six days at 2200 m substantially decreases acute mountain sickness (AMS) and improves work performance after rapid ascent to 4300 m. There is evidence that 5 or more days above 3000 m within the last 2 months will significantly decrease AMS during a subsequent rapid ascent to 4500 m. Exercise training during the altitude preexposures may augment improvement in physical performance. The persistence of altitude acclimatization after return to low altitude appears to be proportional to the degree of acclimatization developed. The subsequent ascent to high altitude should be scheduled as soon as possible after the last altitude preexposure.

  4. Status of KM3NeT

    NASA Astrophysics Data System (ADS)

    Riccobene, G.

    2016-07-01

    The recent observation of cosmic neutrinos by IceCube has pushed the quest towards the identification of cosmic sources of high-energy particles. The KM3NeT Collaboration is now ready to launch the massive construction of detection units to be installed in deep sea to build a km-cubic size neutrino telescope. The main elements of the detector, the status of the project and the expected perfomances are briefly reported.

  5. Simplified Analytical Solution for Martian OH*-layer Altitude

    NASA Astrophysics Data System (ADS)

    Grygalashvyly, Mykhaylo; Sonnemann, Gerd

    2016-04-01

    In the Earth atmosphere airglow emissions of OH* are used in very diverse branches of research from gravity waves (GWs) and tides observations to minor chemical constituents and temperature measurements. Moreover, the airglow observations have good potential as, for example, for water vapor profile retrieval in the mesopause region. Recently, hydroxyl emissions were found in Mars and in Venus atmospheres. Thus, the applicability potential has been increased in spurts. Even for Earth's atmosphere there is a lack of knowledge on morphology of OH*-layer, i.e. on altitude, number density and shape variability with the intro- and extra-annual cycles, due to planetary waves (PWs), GWs, and tides. The questions on relations between OH* layer altitude, number density (volume emission, intensity), surrounding temperature, and winds (meridional and vertical) are still open. Modern satellite airglow measurements are not enough precise with a typical error in determination of altitude ~2-3 km, while the ground-based measurements are restricted by local point of observations and integrated volume emission. Thus, retrievals of emission altitudes variations to derive are awkward. The difficulties are much stronger for the investigation of the Martian OH*-layer variability and altitude diagnostics. We introduce a simplified analytical approach for OH*-layer altitude in the Martian atmosphere. The expressions for the number density and height of the OH*-layer peak, as well as relationship between both parameters, are derived for night time conditions. These OH*-layer parameters are determined by the temperature, atomic oxygen density and their vertical gradients. The approximations can be useful for analysis of ground-based and satellite-borne airglow observations. We discuss the consequences following from the derived expression.

  6. High altitude, prolonged exercise, and the athlete biological passport.

    PubMed

    Schumacher, Yorck O; Garvican, Laura A; Christian, Ryan; Lobigs, Louisa M; Qi, Jiliang; Fan, Rongyun; He, Yingying; Wang, Hailing; Gore, Christopher J; Ma, Fuhai

    2015-01-01

    The Athlete Biological Passport (ABP) detects blood doping in athletes through longitudinal monitoring of erythropoietic markers. Mathematical algorithms are used to define individual reference ranges for these markers for each athlete. It is unclear if altitude and exercise can affect the variables included in these calculations in a way that the changes might be mistaken for blood manipulation. The aim of this study was to investigate the influence of the simultaneous strenuous exercise and low to high altitude exposure on the calculation algorithms of the ABP. 14 sea level (SL) and 11 altitude native (ALT) highly trained athletes participated in a 14-day cycling stage race taking place at an average altitude of 2496 m above sea level (min. 1014 m, max. 4120 m), race distances ranged between 96 and 227 km per day. ABP blood measures were taken on days -1,3,6,10,14 (SL) and -1,9,15 (ALT) of the race. Four results from three samples of two different SL athletes exceeded the individual limits at the 99% specificity threshold and one value at 99.9%. In ALT, three results from three samples of three different athletes were beyond the individual limits at 99%, one at 99.9%. The variations could be explained by the expected physiological reaction to exercise and altitude. In summary, the abnormalities observed in the haematological ABP´s of well-trained athletes during extensive exercise at altitude are limited and in line with expected physiological changes. Copyright © 2014 John Wiley & Sons, Ltd.

  7. Evolution of the Proposed International Tropical Reference Atmosphere up to 2000 km

    NASA Astrophysics Data System (ADS)

    Ananthasayanam, M.

    There is a compelling need in many aerospace, remote sensing, and other applications to propose a global reference atmosphere encompassing the whole of the tropics, due to the following reasons among others. The tropics cover a large area and the atmospheric conditions there are quite different from those in the midlatitudes represented by the International Standard Atmosphere. Though the dictionary definition of the tropics is between 230 28' N and 230 28' S, there can be no sharp dividing line between the tropics and extra tropics, and dynamical considerations suggest 30 0 N and 300 S as more appropriate approximate boundaries. (During summer tropical conditions prevail up to about 350 N). The early work of Ramanathan in 1929 pointed out that a break in the temperature distribution occurs around 16 km at low latitudes, whereas it occurs at much lower altitudes (around 11 km) in the temperate zone. He also showed that the coldest air over the earth (temperature about 1850 K) is in the form of a flat ring at a height of some 17 km over the equator; thus while mean temperatures are higher at sea level in the tropics, they are lower at altitudes around 15 km. Pisharoty suggested in 1959 two standard atmospheres one for the Asiatic tropics and another called Universal up to 20 km. The slight differences between these two turned out to be not valid from later measurements. Based on the presently available data showing weak longitudinal variations, it indeed turns out to be possible to provide an International Tropical Reference Atmosphere (ITRA) representative of the whole of the tropical region in both the northern and southern hemispheres (Ananthasayanam and Narasimha 1990). This proposal is also consistent with the mean monthly reference atmospheres for the northern hemisphere by Cole and Kantor (1978) and for the southern hemisphere by Koshelkov (1985) and also the Nimbus satellite data of Barnett and Corney (1985) from sea level up to 80 km. For ITRA, either the

  8. High-temperature photoluminescence and photoluminescence excitation spectroscopy of Al0.60Ga0.40N/Al0.70Ga0.30N multiple quantum wells

    NASA Astrophysics Data System (ADS)

    Murotani, Hideaki; Nakamura, Katsuto; Fukuno, Tomonori; Miyake, Hideto; Hiramatsu, Kazumasa; Yamada, Yoichi

    2017-02-01

    The excitonic optical properties of an Al0.60Ga0.40N/Al0.70Ga0.30N multiple quantum well (MQW) structure were studied using photoluminescence (PL) and PL excitation (PLE) spectroscopy at high temperatures. Clear excitonic PL was observed at temperatures up to 750 K. Biexciton luminescence was clearly observed even at this high temperature. These observations unambiguously demonstrated the extremely high thermal stability of biexcitons in this MQW. Furthermore, additional PL peaks were observed on the low-energy side of the biexciton luminescence. The observation of biexciton two-photon resonance in the PLE spectra of these peaks indicates that these peaks can be explained by processes involving inelastic scattering of excitons and biexcitons.

  9. Extrinsic mechanism for giant dielectric response in Ba{sub 0.70}Sr{sub 0.30}(Fe{sub 0.5}Nb{sub 0.5})O{sub 3} ceramic

    SciTech Connect

    Patel, Piyush Kumar Yadav, K. L. Durgesh

    2014-04-24

    To obtain the high dielectric constant, the effect of sintering process on the electrical properties of Ba{sub 0.70}Sr{sub 0.30}(Fe{sub 0.5}Nb{sub 0.5})O{sub 3} ceramics were investigated. X-ray diffraction pattern of the samples at room temperature shows a monoclinic structure. Microstructure analysis shows well-grown and dense microstructure in all the samples. We found giant dielectric constant (∼3.59 × 10{sup 5}) with low dielectric loss (∼0.49) at room temperature for 2 hr sintered sample at 1250 °C. The extrinsic phenomena like interfacial polarization due to space charge accumulation at grain boundaries are discussed.

  10. Heteroepitaxial growth of In{sub 0.30}Ga{sub 0.70}As high-electron mobility transistor on 200 mm silicon substrate using metamorphic graded buffer

    SciTech Connect

    Kohen, David Nguyen, Xuan Sang; Made, Riko I; Lee, Kwang Hong; Lee, Kenneth Eng Kian; Yadav, Sachin; Kumar, Annie; Gong, Xiao; Yeo, Yee Chia; Heidelberger, Christopher; Yoon, Soon Fatt; Fitzgerald, Eugene A.

    2016-08-15

    We report on the growth of an In{sub 0.30}Ga{sub 0.70}As channel high-electron mobility transistor (HEMT) on a 200 mm silicon wafer by metal organic vapor phase epitaxy. By using a 3 μm thick buffer comprising a Ge layer, a GaAs layer and an InAlAs compositionally graded strain relaxing buffer, we achieve threading dislocation density of (1.0 ± 0.3) × 10{sup 7} cm{sup −2} with a surface roughness of 10 nm RMS. No phase separation was observed during the InAlAs compositionally graded buffer layer growth. 1.4 μm long channel length transistors are fabricated from the wafer with I{sub DS} of 70 μA/μm and g{sub m} of above 60 μS/μm, demonstrating the high quality of the grown materials.

  11. Development of Aptitude at Altitude

    ERIC Educational Resources Information Center

    Hogan, Alexandra M.; Virues-Ortega, Javier; Botti, Ana Baya; Bucks, Romola; Holloway, John W.; Rose-Zerilli, Matthew J.; Palmer, Lyle J.; Webster, Rebecca J.; Baldeweg, Torsten; Kirkham, Fenella J.

    2010-01-01

    Millions of people currently live at altitudes in excess of 2500 metres, where oxygen supply is limited, but very little is known about the development of brain and behavioural function under such hypoxic conditions. We describe the physiological, cognitive and behavioural profile of a large cohort of infants (6-12 months), children (6-10 years)…

  12. Development of Aptitude at Altitude

    ERIC Educational Resources Information Center

    Hogan, Alexandra M.; Virues-Ortega, Javier; Botti, Ana Baya; Bucks, Romola; Holloway, John W.; Rose-Zerilli, Matthew J.; Palmer, Lyle J.; Webster, Rebecca J.; Baldeweg, Torsten; Kirkham, Fenella J.

    2010-01-01

    Millions of people currently live at altitudes in excess of 2500 metres, where oxygen supply is limited, but very little is known about the development of brain and behavioural function under such hypoxic conditions. We describe the physiological, cognitive and behavioural profile of a large cohort of infants (6-12 months), children (6-10 years)…

  13. Alaska High Altitude Photography Program

    NASA Technical Reports Server (NTRS)

    Petersen, Earl V.; Knutson, Martin A.; Ekstrand, Robert E.

    1986-01-01

    In 1978, the Alaska High Altitude Photography Program was initiated to obtain simultaneous black and white and color IR aerial photography of Alaska. Dual RC-10 and Zeiss camera systems were used for this program on NASA's U-2 and WB-57F, respectively. Data collection, handling, and distribution are discussed as well as general applications and the current status.

  14. Lidar Altitude Data Read Routine

    Atmospheric Science Data Center

    2013-03-19

    ... Profile products. It is written in Interactive Data Language (IDL) and uses HDF routine calls to read the altitude data which are ... Data Read routine  (1.5 KB) Interactive Data Language (IDL) is available from  Exelis Visual Information Solutions . ...

  15. Altitude Compensating Nozzle Concepts Evaluation

    NASA Technical Reports Server (NTRS)

    Soni, Bharat

    2000-01-01

    This report contains the summary of work accomplished during summer of 2000 by Mr. Chad Hammons, undergraduate senior student, Mississippi State University/ERC in support of NASA/MSFC mission pertinent to Altitude compensating nozzle concepts evaluations. In particular, the development of automatic grid generator applicable in conducting sensitivity analysis involving Aerospike engine is described.

  16. Alaska High Altitude Photography Program

    NASA Technical Reports Server (NTRS)

    Petersen, Earl V.; Knutson, Martin A.; Ekstrand, Robert E.

    1986-01-01

    In 1978, the Alaska High Altitude Photography Program was initiated to obtain simultaneous black and white and color IR aerial photography of Alaska. Dual RC-10 and Zeiss camera systems were used for this program on NASA's U-2 and WB-57F, respectively. Data collection, handling, and distribution are discussed as well as general applications and the current status.

  17. Thermal Structure of the Mesopause Region (80-105 km) at 40°N Latitude. Part I: Seasonal Variations.

    NASA Astrophysics Data System (ADS)

    States, Robert J.; Gardner, Chester S.

    2000-01-01

    Sodium wind/temperature lidar measurements taken throughout the diurnal and annual cycles at Urbana, Illinois (40°N, 88°W), from February 1996 through January 1998 are used to characterize the seasonal variations of the mesospheric temperature structure between 80 and 105 km. By averaging data over several weeks and over the complete diurnal cycle, the significant effects of gravity waves, tides, and planetary waves are surpressed. The observed mean annual temperature structure is largely consistent with the assumption of radiative equilibrium between direct solar UV heating and radiative cooling by IR emission. Large seasonal variations of the mean thermal structure are observed. Below 91 km, there is strong adiabatic cooling in summer caused by the mean upward velocities associated with the diabatic circulation system. The maximum amplitude of the annual variation is 9.7 K at approximately 84 km. Above 98 km, increased UV absorption by O2 during summer drives an annual oscillation in this region with an amplitude of approximately 5 K. These two phenomena determine the seasonal variation of the mesopause altitude. The annual variation in solar UV heating in the lower thermosphere induces a modest 5-km peak to peak annual variation in the mesopause altitude. The mesopause is near 101 km in winter and 96 km in late summer. However, the summer cooling below 91 km is strong enough to define the minimum temperature, causing the mesopause altitude to fall to 87 km from about 7 May to about 15 July (70 days). The mesopause thickness, defined here as the altitude range where the temperature is within 5 K of the minimum, increases dramatically from approximately 7 km in winter to over 16 km in summer. Significant biases can occur in some parameters calculated from nighttime-only observations. The inversion layers that persist between 85 and 96 km in nighttime temperature profiles are virtually eliminated when data are averaged over the complete diurnal period. The strong

  18. Lower-Thermosphere Metals and High Altitude Meteoroid Sputtering

    NASA Astrophysics Data System (ADS)

    Raizada, S.; Mathews, J. D.; Kesaraju, S.

    2016-12-01

    Recent lidar observations of atomic Fe, Na, and K at altitudes well above the traditional meteor zone violate the usual assumptions regarding atmospheric metals. While suggested sources of these metals include ion-to-neutral conversion and rapid vertical bulk transport due to intense acoustic-gravity wave breaking, we suggest a direct source. That is, confirmation of radar and optical meteors at altitudes well above the ablation-defined meteor zone points to a direct source of these high-altitude metals due to sputtering of cold, fast meteoroids. Interesting complications to this scenario arise as many of these high altitude meteoroids appear to be fragmenting suggesting these are complex "dirty-ice" and "dust-ball" meteoroids comprised of small, dense grains weakly bound together by more volatile substances. As they enter the 150-200 km atmosphere these meteoroids may disperse into a more extended "coma" that presents a more complex interaction region and interaction process with the atmosphere. We discuss sputtering, the impact energies needed for onset of sputtering, sputtering yield, and the observational evidence available for interpretation of meteoroid sputtering as a source of aeronomically interesting metals above the classical meteor zone.

  19. A genetic mechanism for Tibetan high-altitude adaptation.

    PubMed

    Lorenzo, Felipe R; Huff, Chad; Myllymäki, Mikko; Olenchock, Benjamin; Swierczek, Sabina; Tashi, Tsewang; Gordeuk, Victor; Wuren, Tana; Ri-Li, Ge; McClain, Donald A; Khan, Tahsin M; Koul, Parvaiz A; Guchhait, Prasenjit; Salama, Mohamed E; Xing, Jinchuan; Semenza, Gregg L; Liberzon, Ella; Wilson, Andrew; Simonson, Tatum S; Jorde, Lynn B; Kaelin, William G; Koivunen, Peppi; Prchal, Josef T

    2014-09-01

    Tibetans do not exhibit increased hemoglobin concentration at high altitude. We describe a high-frequency missense mutation in the EGLN1 gene, which encodes prolyl hydroxylase 2 (PHD2), that contributes to this adaptive response. We show that a variant in EGLN1, c.[12C>G; 380G>C], contributes functionally to the Tibetan high-altitude phenotype. PHD2 triggers the degradation of hypoxia-inducible factors (HIFs), which mediate many physiological responses to hypoxia, including erythropoiesis. The PHD2 p.[Asp4Glu; Cys127Ser] variant exhibits a lower K(m) value for oxygen, suggesting that it promotes increased HIF degradation under hypoxic conditions. Whereas hypoxia stimulates the proliferation of wild-type erythroid progenitors, the proliferation of progenitors with the c.[12C>G; 380G>C] mutation in EGLN1 is significantly impaired under hypoxic culture conditions. We show that the c.[12C>G; 380G>C] mutation originated ∼8,000 years ago on the same haplotype previously associated with adaptation to high altitude. The c.[12C>G; 380G>C] mutation abrogates hypoxia-induced and HIF-mediated augmentation of erythropoiesis, which provides a molecular mechanism for the observed protection of Tibetans from polycythemia at high altitude.

  20. The physical nature of interplanetary dust as inferred by particles collected at 35 km. [morphology of micrometeorites and ablation products

    NASA Technical Reports Server (NTRS)

    Brownlee, D. E.; Hodge, P. W.; Bucher, W.

    1973-01-01

    Particles were collected at an altitude of 35 km by two flights of a volume sampling micrometeorite collector. The collection scheme is very sensitive and is capable of collecting a significant number of particles. Many of the particles collected have chemical compositions similar to solar or to iron meteorites. Morphology of collected particles indicates that both true micrometeorites and ablation products were collected.

  1. How simulated fluence of photons from terrestrial gamma ray flashes at aircraft and balloon altitudes depends on initial parameters

    NASA Astrophysics Data System (ADS)

    Hansen, R. S.; ØStgaard, N.; Gjesteland, T.; Carlson, B.

    2013-05-01

    Up to a few years ago, terrestrial gamma ray flashes (TGFs) were only observed by spaceborne instruments. The aircraft campaign ADELE was able to observe one TGF, and more attempts on aircraft observations are planned. There is also a planned campaign with stratospheric balloons, COBRAT. In this context an important question that arises is what count rates we can expect and how these estimates are affected by the initial properties of the TGFs. Based on simulations of photon propagation in air we find the photon fluence at different observation points at aircraft and balloon altitudes. The observed fluence is highly affected by the initial parameters of the simulated TGFs. One of the most important parameters is the number of initial photons in a TGF. In this paper, we give a semi-analytical approach to find the initial number of photons with an order of magnitude accuracy. The resulting number varies over several orders of magnitude, depending mostly on the production altitude of the TGF. The initial production altitude is also one of the main parameters in the simulations. Given the same number of initial photons, the fluence at aircraft and balloon altitude from a TGF produced at 10 km altitude is 2-3 orders of magnitude smaller then a TGF originating from 20 km altitude. Other important parameters are altitude distribution, angular distribution and amount of feedback. The differences in altitude, altitude distribution and amount of feedback are especially important for the fluence of photons observed at altitudes less than 20 km, and for instruments with a low-energy threshold larger than 100 keV. We find that the maximum radius of observation in 14 km for a TGF with the intensity of an average RHESSI TGF is smaller than the results reported by Smith et al. (2011), and our results support the conclusion in Gjesteland et al. (2012) and Østgaard et al. (2012) that TGFs probably are a more common phenomenon than previously reported.

  2. Global dust altitude climatology based on CALIPSO observations

    NASA Astrophysics Data System (ADS)

    Tsamalis, C.; Chedin, A.; Peyridieu, S.

    2011-12-01

    Dust aerosols are important constituents of the earth climate as they influence many processes of the planet. They affect the earth's radiative budget via the direct, the indirect and the semi-direct effects, which cause the modification of the mesoscale dynamics at short time scales and the climate change at long time scales, they act as cloud condensation and ice nuclei and therefore have strong implications in the hydrological cycle, their deposition in the ocean supplies it with nutrients, which in turn affect the ocean biogeochemistry, they impact the atmospheric concentrations of trace gases, via heterogeneous reactions, they contribute to air pollution and they degrade the restitution of atmospheric or surface parameters from satellite instruments. An important parameter of the dust aerosols is their altitude as it defines their impact on the aforementioned processes. But this parameter is not easily measurable except from lidars and more recently from passive infrared remote sensors. Nevertheless, ground based lidars are situated at specific locations and cannot offer a global view of the dust altitude, while dedicated campaigns using lidars and in situ measurements are restricted in time. On the other hand, the passive instruments AIRS or IASI offer a good spatial coverage, but their new established results need further validation. Launched in April 2006, the satellite CALIPSO, with the on board two wavelength depolarisation lidar CALIOP, permits an accurate determination of the aerosols altitude. Moreover, the depolarisation at 532 nm allows the discrimination between dust and other types of aerosols, which generally do not depolarize light. Nevertheless, the beam diameter of 70 m at the earth's surface makes it difficult to interpret statistically the results, as the 16 days repetition cycle of CALIPSO does not cover all the earth. In order to overcome this difficulty, the L2 5 km aerosol layer product (version 3.01) is used here to calculate the

  3. Experimental quantum digital signature over 102 km

    NASA Astrophysics Data System (ADS)

    Yin, Hua-Lei; Fu, Yao; Liu, Hui; Tang, Qi-Jie; Wang, Jian; You, Li-Xing; Zhang, Wei-Jun; Chen, Si-Jing; Wang, Zhen; Zhang, Qiang; Chen, Teng-Yun; Chen, Zeng-Bing; Pan, Jian-Wei

    2017-03-01

    Quantum digital signature (QDS) is an approach to guarantee the nonrepudiation, unforgeability, and transferability of a signature with information-theoretical security. Previous experimental realizations of QDS relied on an unrealistic assumption of secure channels and the longest distance is several kilometers. Here, we have experimentally demonstrated a recently proposed QDS protocol without assuming any secure channel. Exploiting the decoy state modulation, we have successfully signed a one-bit message through an up to 102-km optical fiber. Furthermore, we continuously run the system to sign the longer message "USTC" with 32 bits at the distance of 51 km. Our results pave the way towards the practical application of QDS.

  4. [Children and pregnant women at high altitude].

    PubMed

    Rehakova, P; Rexhaj, E; Farron, F; Duplain, H

    2014-05-07

    Nowadays, high altitude resorts have become popular destinations for family vacations. Based on a limited number of publications and international guidelines, this article summarizes the effects of high altitude on children and pregnant women. Children also suffer from high altitude-related diseases, however their presentation and clinical significance are different from their adult counterparts. Careful planning of the itinerary with respect to altitude of the overnight stays, access to medical services and potential evacuation routes is the cornerstone of a successful vacation.

  5. Altitude characteristics of selected air quality analyzers

    NASA Technical Reports Server (NTRS)

    White, J. H.; Strong, R.; Tommerdahl, J. B.

    1979-01-01

    The effects of altitude (pressure) on the operation and sensitivity of various air quality analyzers frequently flown on aircraft were analyzed. Two ozone analyzers were studied at altitudes from 600 to 7500 m and a nitrogen oxides chemiluminescence detector and a sulfur dioxide flame photometric detector were studied at altitudes from 600 to 3000 m. Calibration curves for altitude corrections to the sensitivity of the instruments are presented along with discussion of observed instrument behavior.

  6. PHOTOGRAPHIC TRACKING FOR HIGH ALTITUDE SATELLITES,

    DTIC Science & Technology

    TRACKING, *COMMUNICATION SATELLITES, ARTIFICIAL SATELLITES, TRACKING CAMERAS, COMMUNICATION SATELLITES, PHOTOGRAPHY, SATELLITE ATTITUDE, ORBITS, ERRORS, CORRECTIONS, HIGH ALTITUDE , ILLUMINATION, STARS.

  7. Low-altitude trapped protons at the geomagnetic equator

    NASA Technical Reports Server (NTRS)

    Guzik, T. G.; Miah, M. A.; Mitchell, J. M.; Wefel, J. P.

    1989-01-01

    Geomagnetically trapped protons in the 0.6- to 9-MeV energy range were measured at latitudes near the geomagnetic equator by the Phoenix 1 experiment on board the S81-1 mission from May to November 1982. The protons show a distribution in latitude along the line of minimum magnetic field strength with a full width at half maximum of about 10 deg but with no appreciable longitudinal variation. Between 170 and 290 Km the peak proton flux shows a fifth-power altitude dependence, in contrast to previous measurements at higher altitudes, possibly demonstrating source attenuation. The efficiency of the telescope is calculated as a function of particle pitch angle and used to investigate the time dependence (1969-1982) of the intensity.

  8. High-altitude balloon experiment

    NASA Astrophysics Data System (ADS)

    Browning, William M.; Olson, David S.; Keenan, Donald E.

    1998-09-01

    The mission of the High Altitude Balloon Experiment (HABE) is to resolve critical acquisition, tracking, and pointing (ATP) and fire control issues, validate enabling technologies, and acquire supporting data for future space- based laser experiments. HABE is integrating components from existing technologies into a payload that can autonomously acquire, track, and point a lower power laser at a ballistic missile in its boost phase of flight. For its primary mission the payload will be flown multiple times to an altitude of 85,000 feet above the White Sands Missile Range. From the near-space environment of the balloon flight, HABE will demonstrate the ATP functions required for a space- based laser in a ballistic missile defense role. The HABE platform includes coarse and fine gimbal pointing, infrared and visible passive tracking, active fine tracking, internal auto-alignment and boresighting, and precision line-of-sight stabilization functions. This paper presents an overview and status of the HABE program.

  9. High Altitude Ozone Research Balloon

    NASA Technical Reports Server (NTRS)

    Cauthen, Timothy A.; Daniel, Leslie A.; Herrick, Sally C.; Rock, Stacey G.; Varias, Michael A.

    1990-01-01

    In order to create a mission model of the high altitude ozone research balloon (HAORB) several options for flight preparation, altitude control, flight termination, and payload recovery were considered. After the optimal launch date and location for two separate HAORB flights were calculated, a method for reducing the heat transfer from solar and infrared radiation was designed and analytically tested. This provided the most important advantage of the HAORB over conventional balloons, i.e., its improved flight duration. Comparisons of different parachute configurations were made, and a design best suited for the HAORB's needs was determined to provide for payload recovery after flight termination. In an effort to avoid possible payload damage, a landing system was also developed.

  10. Rocket Altitude Test Facilities Register

    DTIC Science & Technology

    1987-03-01

    Classification of Document UNCLASSIFIED 5. Originator Advisory Group for Aerospace Research and Development North Atlantic Treaty Organization...Emphasis was put on facilities capable of performing research and development tests. This AGARDograph was prepared at the request of the Propulsion... RESEARCH & DEVELOPMENT 7RUEANCELLE 92200 NEUILLY SUR SEINE FRANCE AGARDo^raph N0^97 , Rocket Altitude Test Facilities Register /^ri c^ris

  11. Measuring high-altitude adaptation.

    PubMed

    Moore, Lorna G

    2017-08-31

    High altitudes (>8000 ft or 2500 m) provide an experiment of nature for measuring adaptation and the physiological processes involved. Studies conducted over the past ~25 years in Andeans, Tibetans, and less often Ethiopians show varied but distinct O2 transport traits from those of acclimatized newcomers, providing indirect evidence for genetic adaptation to high altitude. Short-term (acclimatization, developmental) and long-term (genetic) responses to high altitude exhibit a temporal gradient such that, while all influence O2 content, the latter also improve O2 delivery and metabolism. Much has been learned concerning the underlying physiological processes but additional studies are needed on the regulation of blood flow and O2 utilization. Direct evidence of genetic adaptation comes from single nucleotide polymorphism (SNP)-based genome scans and whole-genome sequencing studies that have identified gene regions acted upon by natural selection. Efforts have begun to understand the connections between the two with Andean studies on the genetic factors raising uterine blood flow, fetal growth, and susceptibility to Chronic Mountain Sickness and Tibetan studies on genes serving to lower hemoglobin and pulmonary arterial pressure. Critical for future studies will be the selection of phenotypes with demonstrable effects on reproductive success, the calculation of actual fitness costs, and greater inclusion of women among the subjects being studied. The well-characterized nature of the O2 transport system, the presence of multiple long-resident populations, and relevance for understanding hypoxic disorders in all persons underscore the importance of understanding how evolutionary adaptation to high altitude has occurred. Copyright © 2017, Journal of Applied Physiology.

  12. Pulmonary Adaptation to High Altitude.

    DTIC Science & Technology

    1986-02-01

    following active expiration) and may even spare diaphragmatic contraction at the initia- tion of inspiration. On the other hand, the fall in FRC reduces...the failure of the lung’s gas exchange and ventilatory control system and chest wall mechanics to respond adequately and/or efficiently to heavy work in...prediction of gas exchange I" failure " at high altitudes. Our recent findings also strongly implicate a highly significant role for pulmonary and chest

  13. Pulmonary Adaptation to High Altitude.

    DTIC Science & Technology

    1983-08-12

    Thus far several of our findings point to the occurrence of excessive flow- resistive work and perhaps even diaphragmatic fatigue during heavy...hypoxia have been the subject of our investigations. Our work has detailed the critical limitations to oxygen transport presented by the failure of the...nesurements of arterial 02 saturation--should provide excellent prediction of gas exchange " failure " at high altitudes. Our recent findings

  14. Low altitude plume impingement handbook

    NASA Technical Reports Server (NTRS)

    Smith, Sheldon D.

    1991-01-01

    Plume Impingement modeling is required whenever an object immersed in a rocket exhaust plume must survive or remain undamaged within specified limits, due to thermal and pressure environments induced by the plume. At high altitudes inviscid plume models, Monte Carlo techniques along with the Plume Impingement Program can be used to predict reasonably accurate environments since there are usually no strong flowfield/body interactions or atmospheric effects. However, at low altitudes there is plume-atmospheric mixing and potential large flowfield perturbations due to plume-structure interaction. If the impinged surface is large relative to the flowfield and the flowfield is supersonic, the shock near the surface can stand off the surface several exit radii. This results in an effective total pressure that is higher than that which exists in the free plume at the surface. Additionally, in two phase plumes, there can be strong particle-gas interaction in the flowfield immediately ahead of the surface. To date there have been three levels of sophistication that have been used for low altitude plume induced environment predictions. Level 1 calculations rely on empirical characterizations of the flowfield and relatively simple impingement modeling. An example of this technique is described by Piesik. A Level 2 approach consists of characterizing the viscous plume using the SPF/2 code or RAMP2/LAMP and using the Plume Impingement Program to predict the environments. A Level 3 analysis would consist of using a Navier-Stokes code such as the FDNS code to model the flowfield and structure during a single calculation. To date, Level 1 and Level 2 type analyses have been primarily used to perform environment calculations. The recent advances in CFD modeling and computer resources allow Level 2 type analysis to be used for final design studies. Following some background on low altitude impingement, Level 1, 2, and 3 type analysis will be described.

  15. Profiles of temperature and density based on extremes at 5, 10, 20, 30 and 40 km

    NASA Technical Reports Server (NTRS)

    Kantor, A. J.; Tattelmann, P.; Marcos, F. A.

    1985-01-01

    Information on the vertical distribution of expected extremes of temperature and density are required for the design and operation of systems traversing the atmosphere. Such data are particularly important at altitudes from the surface to approximately 80 km for developing all types of airborne vehicles ranging from helicopters and airplanes to sophisticated aerospace systems. Vertical profiles of temperature and density have been developed based on 1- and 10-percent hot and cold temperatures and 1- and 10- percent high and low densities occurring during the most severe month at the worst locations for which reliable upper-air data are available. The model profiles, from the surface to 80 km, are based on extremes that occur at 5, 10, 20, 30, and 40 km. There are 20 profiles for extreme temperatures (5 levels by 4 percentiles) that include associated densities, and 20 analogous profiles for extreme densities including associated temperatures. Consequently, a set of realistic profiles (rather than envelopes) of temperature and density, associated with extremes at each of 5 specified levels in the troposphere and stratosphere, are now available for altitudes up to 80 km.

  16. Aero-thermo-dynamic analysis of the Spaceliner-7.1 vehicle in high altitude flight

    NASA Astrophysics Data System (ADS)

    Zuppardi, Gennaro; Morsa, Luigi; Sippel, Martin; Schwanekamp, Tobias

    2014-12-01

    SpaceLiner, designed by DLR, is a visionary, extremely fast passenger transportation concept. It consists of two stages: a winged booster, a vehicle. After separation of the two stages, the booster makes a controlled re-entry and returns to the launch site. According to the current project, version 7-1 of SpaceLiner (SpaceLiner-7.1), the vehicle should be brought at an altitude of 75 km and then released, undertaking the descent path. In the perspective that the vehicle of SpaceLiner-7.1 could be brought to altitudes higher than 75 km, e.g. 100 km or above and also for a speculative purpose, in this paper the aerodynamic parameters of the SpaceLiner-7.1 vehicle are calculated in the whole transition regime, from continuum low density to free molecular flows. Computer simulations have been carried out by three codes: two DSMC codes, DS3V in the altitude interval 100-250 km for the evaluation of the global aerodynamic coefficients and DS2V at the altitude of 60 km for the evaluation of the heat flux and pressure distributions along the vehicle nose, and the DLR HOTSOSE code for the evaluation of the global aerodynamic coefficients in continuum, hypersonic flow at the altitude of 44.6 km. The effectiveness of the flaps with deflection angle of -35 deg. was evaluated in the above mentioned altitude interval. The vehicle showed longitudinal stability in the whole altitude interval even with no flap. The global bridging formulae verified to be proper for the evaluation of the aerodynamic coefficients in the altitude interval 80-100 km where the computations cannot be fulfilled either by CFD, because of the failure of the classical equations computing the transport coefficients, or by DSMC because of the requirement of very high computer resources both in terms of the core storage (a high number of simulated molecules is needed) and to the very long processing time.

  17. Altitude Wind Tunnel Control Room

    NASA Image and Video Library

    1945-05-21

    Researchers at the National Advisory Committee for Aeronautics (NACA) Aircraft Engine Research Laboratory monitor a ramjet's performance in the Altitude Wind Tunnel from the control room. The soundproof control room was just a few feet from the tunnel’s 20-foot-diameter test section. In the control room, the operators could control all aspects of the tunnel’s operation, including the air density, temperature, and speed. They also operated the engine or test article in the test section by controlling the angle-of-attack, speed, power, and other parameters. The men in this photograph are monitoring the engine’s thrust and lift. A NACA-designed 20-inch-diameter ramjet was installed in the tunnel in May 1945. Thrust figures from these runs were compared with drag data from tests of scale models in small supersonic tunnels to verify the ramjet’s feasibility. The tunnel was used to analyze the ramjet’s overall performance up to altitudes of 47,000 feet and speeds to Mach 1.84. The researchers found that an increase in altitude caused a reduction in the engine’s horsepower and identified optimal flameholder configurations.

  18. Altitude responsive turbocharger control system

    SciTech Connect

    Suzuki, S.

    1984-09-04

    A turbocharger control system has a waste gate operative to cause engine exhaust gases to bypass the turbo-charger to protect the engine when the supercharging pressure exceeds a predetermined pressure level. A pressure modulator is provided to mix pressures derived from points upstream and downstream of a compressor to produce a controlling pressure which is modulated to be of a pressure level between the compressor-upstream and downstream pressures and which is also adjusted as a function of the atmospheric pressure. A waste gate actuator compares the supercharging pressure and the controlling pressure to control the operation of the waste gate. When a motor vehicle equipped with the system is operated at high altitude where the atmospheric pressure is lower than that obtained at a low altitude, the controlling pressure is adjusted to be substantially the same as the controlling pressure obtained at the low altitude, whereby the waste gate is opened only at a predetermined pressure level of the supercharging pressure to assure a good engine operability.

  19. Venusian atmospheric equilibrium chemistry at the Pioneer Venus anomalous event altitude

    NASA Technical Reports Server (NTRS)

    Craig, Roger A.

    1994-01-01

    No convincing explanation for the anomalous behavior of the Atmospheric Structure Experiment temperature sensors at approximately 13 km altitude has been found. It occurred on all of the widely-spaced probes, in a similar fashion. A preliminary effort has been made to determine atmospheric chemical species which might be present at 13 km. The purpose of this effort is to initiate suggestions of possible chemical interactions and to explore the effects of the presence of possible metal reactants including condensation. Equilibrium fractions of chemical species were calculated at a variety of conditions. Baseline calculations were made for the altitudes near 13 km. For comparison calculations were also made at 13 km but with the introduction of plausible metal atoms.

  20. Plasma cortisol and testosterone following 19-km and 42-km kayak races.

    PubMed

    Lutoslawska, G; Obminski, Z; Krogulski, A; Sendecki, W

    1991-12-01

    Plasma cortisol and testosterone levels were examined in five, elite, male kayakers before and after 19-km and 42-km kayak races. Both races resulted in significant elevation in plasma cortisol and observed increase is likely to depend on race duration, being much more pronounced after 42-km race compared to 19-km. It should be stressed that observed elevation in cortisol level after 42-km race was higher than reported previously after a marathon run. This finding is in line with reports on hormonal changes in response to arms exercise. Both contests caused a decrease in plasma testosterone level, but the difference between races was not significant. Testosterone/cortisol ratio dropped significantly immediately after the races and the observed decrease was more dominant after the 42-km distance. On the next day, 18 h after the races plasma cortisol, testosterone levels and T/C ratio returned to basal level indicating recuperation from post exercise changes.

  1. A study on H2-TPR of Pt/Ce0.27Zr0.73O2 and Pt/Ce0.27Zr0.70La0.03Ox for soot oxidation

    NASA Astrophysics Data System (ADS)

    Zhang, Hailong; Wang, Jianli; Zhang, Yanhua; Jiao, Yi; Ren, Chengjun; Gong, Maochu; Chen, Yaoqiang

    2016-07-01

    Pt/Ce0.27Zr0.73O2 and Pt/Ce0.27Zr0.70La0.03Ox catalysts, prepared by co-precipitation and impregnation methods, were thermally treated at different temperatures for 10 h and then characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), H2 temperature-programmed reduction (H2-TPR), thermogravimetric analysis (TGA) and soot temperature-programmed oxidation (soot-TPO). Due to thermal effect on the structural and textural properties, the aged catalysts show increased reduction temperatures. But, interestingly, more H2 consumption is detected, which would be ascribed to the increased mobility of bulk oxygen and surface lattice oxygen. The promoting and synergistic roles of Pt in H2-TPR are discussed and it reveals that the sintering and encapsulation of Pt would weaken the H2 spillover mechanism and the addition of La is beneficial to stabilize the synergistic effect between Pt and Ce. On the other hand, a humble role of Pt on promoting soot oxidation activity is found in this study. Not all oxygen species available in H2-TPR can be used for soot oxidation. The deactivation of the aged catalysts is closely related to the reduction temperature.

  2. Hot-Injection Synthesis of Cu-Doped Cu₂ZnSnSe₄ Nanocrystals to Reach Thermoelectric zT of 0.70 at 450°C.

    PubMed

    Chen, Dongsheng; Zhao, Yan; Chen, Yani; Wang, Biao; Wang, Yuanyuan; Zhou, Jun; Liang, Ziqi

    2015-11-11

    As a new class of potential midrange temperature thermoelectric materials, quaternary chalcogenides like Cu2ZnSnS4 (CZTS) and Cu2ZnSnSe4 (CZTSe) suffer from low electrical conductivity due to insufficient doping. In this work, Cu-doped CZTSe nanocrystals consisting of polygon-like nanoparticles are synthesized with sufficient Cu doping contents. The hot-injection synthetic method, rather than the traditional one-pot method, in combination with the hot-pressing method is employed to produce the CZTSe nanocrystals. In Cu-doped CZTSe nanocrystals, the electrical conductivity is enhanced by substitution of Zn(2+) with Cu(+), which introduces additional holes as charge carriers. Meanwhile, the existence of boundaries between nanoparticles in as-synthesized CZTSe nanocrystals collectively results in intensive phonon-boundary scatterings, which remarkably reduce the lattice thermal conductivity. As a result, an average thermoelectric figure of merit of 0.70 is obtained at 450 °C, which is significantly larger than that of the state-of-the-art quaternary chalcogenides thermoelectric materials. The theoretical calculations from the Boltzmann transport equations and the modified effective medium approximation are in good agreement with the experimental data.

  3. Aerodynamic Loads at Mach Numbers from 0.70 to 2.22 on a Airplane Model Having a Wing and Canard of Triangular Plan Form and Either Single or Twin Vertical Tails

    NASA Technical Reports Server (NTRS)

    Peterson, Victor L.; Menees, Gene P.

    1961-01-01

    Results of an investigation of the aerodynamic loads on a canard airplane model are presented without detailed analysis for the Mach number range of 0.70 t o 2.22. The model consisted of a triangular wing and canard of aspect ratio 2 mounted on a Sears-Haack body of fineness ratio 12.5 and either a single body-mounted vertical tail or twin wing mounted vertical tails of low aspect ratio and sweptback plan form. The body, right wing panel, single vertical tail, and left twin vertical tail were instrumented for measuring pressures. Data were obtained for angles of attack ranging from -4 degrees to +16 degrees, nominal canard deflection angles of 0 degrees and 10 degrees, and angles of sideslip of 0 degrees and 5.3 degrees. The Reynolds number was 2.9 x 10(exp 6) based on the wing mean aerodynamic chord. Selected portions of the data are presented in graphical form and attention is directed to some of the results of the investigation. All of the experimental results have been tabulated in the form of pressure coefficients and integrations of the pressure coefficients and are available as supplements to this paper. A brief summary of the contents of the tabular material is given.

  4. Tunability of optical gain (SWIR region) in type-II In0.70Ga0.30As/GaAs0.40Sb0.60 nano-heterostructure under high pressure

    NASA Astrophysics Data System (ADS)

    Nirmal, H. K.; Yadav, Nisha; Dalela, S.; Rathi, Amit; Siddiqui, M. J.; Alvi, P. A.

    2016-06-01

    The interest in applying an external pressure on a nano-heterostructure is to attempt to extract more information about the electronic structure through distortion of the electronic structure. This paper reports the tunability of the optical gain under the high pressure effect in M-shaped type-II In0.70Ga0.30As/GaAs0.40Sb0.60 symmetric lasing nano-heterostructure designed for SWIR generation. In order to simulate the optical gain, the heterostructure has been modeled with the help of six band k.p method. The 6×6 diagonalized k.p Hamiltonian has been solved to evaluate the valence sub-bands (i.e. light and heavy hole energies); and then optical matrix elements and optical gain within TE (Transverse Electric) mode has been calculated. For the injected carrier density of 5×1012/cm2, the optimized optical gain within TE mode is as high as ~9000/cm at the wavelength of ~1.95 μm, thus providing a very important alternative material system for the generation of SWIR wavelength region. The application of very high pressure (2, 5 and 8 GPa) on the structure along [110] direction shows that the gain as well as lasing wavelength both approach to higher values. Thus, the structure can be tuned externally by the application of high pressure within the SWIR region.

  5. Pb0.94La0.04[(Zr0.70Sn0.30)0.90Ti0.10]O3 antiferroelectric bulk ceramics for pulsed capacitors with high energy and power density

    NASA Astrophysics Data System (ADS)

    Xu, Ran; Li, Borui; Tian, Jingjing; Xu, Zhuo; Feng, Yujun; Wei, Xiaoyong; Huang, Dong; Yang, Lanjun

    2017-04-01

    Pb0.94La0.04[(Zr0.70Sn0.30)0.90Ti0.10]O3 antiferroelectric (AFE) bulk ceramics with both excellent energy storage and release properties were fabricated via the solid-state reaction method. The ceramics exhibited a high releasable energy density of 1.39 J/cm3, high efficiency of 92%, and good temperature stability under 104 kV/cm. Fast discharge current was measured, and a large current density up to 820 A/cm2 was achieved. The nonlinear dielectric behavior resulted in the variation of the discharge period of AFE ceramics. The stored charge was released completely due to the low remanent polarization, and the actually released energy density was about 1.0 J/cm3 in 400 ns. A high peak power density of 6.4 × 109 W/kg without a load resistor and an average power density of 3.16 × 108 W/kg with a 204.7 Ω load resistor were achieved in the rapid discharge process. The excellent energy storage and release properties indicate that the obtained antiferroelectric bulk ceramics are very promising for submicrosecond pulsed capacitors.

  6. Low Altitude Initiation of Ionospheric Upflow and Outflow

    NASA Astrophysics Data System (ADS)

    Burleigh, M.; Zettergren, M. D.; Rowland, D. E.; Klenzing, J.

    2015-12-01

    Significant amounts of ionospheric plasma can be transported to high altitudes (above 1000 km) in response to a variety of plasma heating and uplifting processes. Soft electron precipitation heats ambient, F-region ionospheric electrons creating electron pressure increases and upflows. Strong DC electric fields frictionally heat the ion population also resulting in ion upflows. Lastly, field-aligned thermospheric winds can contribute to ion motion at lower altitudes, while geomagnetically perpendicular winds may affect frictional heating. Once ions have been lifted to high altitudes, transverse ion acceleration by broadband ELF waves can give the upflowing ions sufficient energy to escape into the magnetosphere (ionospheric outflow). This study examines the thermospheric wind regulation of ionospheric upflow and outflow with a focus on how lower ionosphere dynamics feed source populations for transverse energization and determine the types, and amounts, of outflowing ions. The model used here for this study is a 2D ionospheric model based on a modified 16-moment transport description. It solves conservation of mass, momentum, and parallel and perpendicular energy for all relevant ionospheric species. This model encapsulates ionospheric upflow and outflow processes through the inclusion of DC electric fields, and empirical descriptions of heating by soft electron precipitation and BBELF waves. This model is used to conduct a parametric study of neutral wind effects on upflow and outflow and highlights how low-altitude processes affect ion outflow through the regulation of source plasma available to higher altitudes. This model is also used to construct a case study of ion outflows at the nightside polar cap boundary using data from the VISIONS sounding rocket campaign.

  7. In-situ Measurements of the Cosmic Radiation on the Aircraft Altitude over Korean Peninsula

    NASA Astrophysics Data System (ADS)

    Lee, J.; Park, I.; Lee, J.; Oh, S.; Kim, Y. C.

    2014-12-01

    This study presents the comparison between the measured and modeled cosmic radiation on aircraft altitude over Korean peninsula. We performed the measurement with a radiation spectrometer, Liulin-6K on board a Republic of Korea (ROK) Air Force aircraft accomplishing the high-altitude (above 9 km) flight over Korea, and the modeled data was obtained from the operational modeling program, CARI-6M developed by FAA. A number of measurements for the flight mission at high-altitude have been executed to evaluate the exposed dose of cosmic radiation. Both the measured and the calculated data show that the exposed radiation dose enhances dramatically as the altitude increases. The results reveal that the exposed dose rate of aircrews at high-altitude flight is 2-3 orders of magnitude (1-2 mSv/hour) higher than the exposure rate at sea level. It is inferred that the annual total dose of radiation for the aircrews at high-altitude could be higher than the annually public limit (1 mSv) recommended by ICRP. Finally, since neutrons are the dominant components reflecting among total cosmic radiation above 9 km, we try to analyze the relationship between the neutron count from the neutron monitor on the ground and the effective dose from the on board spectrometer. Based on these results, it is suggested that the annual criterion and the proper managing procedure of exposed dose for the flight aircrews of ROK Air Force should be regulated.

  8. Space Operations Center orbit altitude selection strategy

    NASA Technical Reports Server (NTRS)

    Indrikis, J.; Myers, H. L.

    1982-01-01

    The strategy for the operational altitude selection has to respond to the Space Operation Center's (SOC) maintenance requirements and the logistics demands of the missions to be supported by the SOC. Three orbit strategies are developed: two are constant altitude, and one variable altitude. In order to minimize the effect of atmospheric uncertainty the dynamic altitude method is recommended. In this approach the SOC will operate at the optimum altitude for the prevailing atmospheric conditions and logistics model, provided that mission safety constraints are not violated. Over a typical solar activity cycle this method produces significant savings in the overall logistics cost.

  9. Altitude-Related Illness: Advice to Travellers

    PubMed Central

    Crutcher, Rodney A.

    1990-01-01

    Altitude-related medical problems have received much attention in the recent medical literature. Family physicians must be knowledgeable about these problems so that they can give appropriate advice to travellers. The author, a practising family physician, discusses issues arising from both the modest cabin altitudes experienced in modern-day air travel and the greater altitudes experienced by skiers and trekkers, pilots and mountaineers, and lowland adventurers of all sorts. He reviews the process of acclimatization to altitude and the four principal forms of altitude illness. PMID:21233912

  10. Effects of Altitude on Turbojet Engine Performance

    NASA Technical Reports Server (NTRS)

    Fleming, William A

    1951-01-01

    Component and over-all performance characteristics of several turbojet engines investigated in the altitude facilities of the NACA Lewis Laboratory during the last several years are summarized to indicate the effects of altitude on turbojet engine performance. Data presented show that failure of turbojet engine performance to generalize for all altitudes can be traced to reductions in compressor efficiency, corrected air flow, and combustion efficiency at altitude. In addition, it is shown that although engines of different design may have equal thrusts at sea level, the thrusts at altitude may vary widely because of differences in compressor performance characteristics from one engine to another.

  11. An altitude-dependent spacecraft charging model

    NASA Technical Reports Server (NTRS)

    Haffner, J. W.

    1977-01-01

    A model for the altitude dependence of the hot plasma parameters responsible for the electrostatic charging of spacecraft was developed. Based upon plasma orbit theory, the directed velocity is a function of the ambient magnetic field flux density. A consequence of this approach is that while the thermal velocity distributions (assumed to be Maxwellian) of the plasma particles are independent of the magnetic field strength (and hence altitude), the particle densities increase with magnetic field strength. Thus, according to this model, while the equilibrium voltage is independent of altitude, the charging current density increases with decreasing altitude. However, the probability of such spacecraft charging decreases with decreasing altitude.

  12. Monthly mean global climatology of temperature, wind, geopotential height and pressure for 0-120 km

    NASA Technical Reports Server (NTRS)

    Chandra, Sushil; Schoeberl, Mark R.; Fleming, Eric L.; Barnett, John J.

    1990-01-01

    This paper presents a monthly mean climatology of zonal mean temperature, zonal wind, and geopotential height with nearly pole-to-pole coverage (80 deg S-80 deg N) for 0-120 km which can be used as a function of altitude and pressure. This climatology reproduces most of the characteristic features of the atmosphere such as the lowering and cooling of the mesopause and the lowering and warming of the stratopause during the summer months at high latitudes. A series of zonal wind profiles is also presented comparing this climatological wind with monthly mean climatological direct wind measurements in the upper mesosphere and lower thermosphere. The two data sets compare well below 80 km, with some general seasonal trend agreement observed above 80 km. The zonal wind at the equator presented here simulates the observed features of the semiannual oscillation in the upper stratosphere and mesosphere.

  13. Gravity wave and tidal structures between 60 and 140 km inferred from space shuttle reentry data

    NASA Technical Reports Server (NTRS)

    Fritts, David C.; Wang, Ding-Yi; Blanchard, Robert C.

    1993-01-01

    This study presents an analysis of density measurements made using high-resolution accelerometers aboard several space shuttles at altitudes from 60 to 140 km during reentry into the earth's atmosphere. The observed density fluctuations are interpreted in terms of gravity waves and tides and provide evidence of the importance of such motions well into the thermosphere. Height profiles of fractional density variance reveal that wave amplitudes increase at a rate consistent with observations at lower levels up to about 90 km. The rate of amplitude growth decreases at greater heights, however, and appears to cease above about 110 km. Wave amplitudes are nevertheless large at these heights and suggest that gravity waves may play an important role in forcing of the lower thermosphere.

  14. Balloon borne in-situ detection of OH in the stratosphere from 37 to 23 km

    NASA Technical Reports Server (NTRS)

    Stimpfle, R. M.; Lapson, L. B.; Wennberg, P. O.; Anderson, J. G.

    1989-01-01

    The OH number density in the stratosphere has been measured over the altitude interval of 37 to 23 km at midday via a balloon-borne gondola launched from Palestine, Texas on July 6, 1988. OH radicals are detected with a laser-induced fluorescence instrument employing a 17-kHz-repetition-rate copper vapor laser-pumped dye laser optically coupled to an enclosed flow, in-situ sampling chamber. OH abundances ranged from 88 + or - 3l pptv in the 36 to 35 km interval to 0.9 + or - 0.8 pptv in the 24 to 23 km interval. The stated uncertainty includes that from both measurement precision and accuracy. Simultaneous detection of ozone and water vapor densities was carried out with separate on-board instruments.

  15. Gravity wave and tidal structures between 60 and 140 km inferred from space shuttle reentry data

    SciTech Connect

    Fritts, D.C. ); Dingyi Wang ); Blanchard, R.C. )

    1993-03-15

    This study presents an analysis of density measurements made using high-resolution accelerometers aboard several space shuttles at altitudes from 60 to 140 km during reentry into the earth's atmosphere. The observed density fluctuations are interpreted in terms of gravity waves and tides and provide evidence of the importance of such motions well into the thermosphere. Height profiles of fractional density variance reveal that wave amplitudes increase at a rate consistent with observations at lower levels up to [approximately]90 km. The rate of amplitude growth decreases at greater heights, however, and appears to cease above [approximately]110 km. Wave amplitudes are nevertheless large at these heights and suggest that gravity waves may play an important role in forcing of the lower thermosphere.

  16. Monthly mean global climatology of temperature, wind, geopotential height and pressure for 0-120 km

    NASA Technical Reports Server (NTRS)

    Chandra, Sushil; Schoeberl, Mark R.; Fleming, Eric L.; Barnett, John J.

    1990-01-01

    This paper presents a monthly mean climatology of zonal mean temperature, zonal wind, and geopotential height with nearly pole-to-pole coverage (80 deg S-80 deg N) for 0-120 km which can be used as a function of altitude and pressure. This climatology reproduces most of the characteristic features of the atmosphere such as the lowering and cooling of the mesopause and the lowering and warming of the stratopause during the summer months at high latitudes. A series of zonal wind profiles is also presented comparing this climatological wind with monthly mean climatological direct wind measurements in the upper mesosphere and lower thermosphere. The two data sets compare well below 80 km, with some general seasonal trend agreement observed above 80 km. The zonal wind at the equator presented here simulates the observed features of the semiannual oscillation in the upper stratosphere and mesosphere.

  17. Daytime vertical and zonal velocities from 150-km echoes: Their relevance to F-region dynamics

    NASA Astrophysics Data System (ADS)

    Chau, Jorge L.; Woodman, Ronald F.

    2004-09-01

    As it was suggested by Kudeki and Fawcett [1993], and later shown by Woodman and Villanueva [1995], vertical Doppler velocities of daytime 150-km echoes represent the vertical E × B drift velocities at F region altitudes. Recently a special experiment was conducted to compare not only the vertical but also the zonal velocities from 150-km echoes with those from an incoherent scatter radar (ISR) mode perpendicular to the magnetic field. The vertical velocity comparisons show that (1) there is a very good agreement between 150-km velocity and the mean F-region E × B drift, and (2) much better agreement is found with the extrapolated values from the ISR altitudinal profiles. On the other hand poor-to-good agreement is found between their zonal components. Our preliminary zonal velocity results, indicate that there is a poor agreement before noontime, while better agreement is found in the afternoon.

  18. Gravity wave and tidal structures between 60 and 140 km inferred from space shuttle reentry data

    NASA Technical Reports Server (NTRS)

    Fritts, David C.; Wang, Ding-Yi; Blanchard, Robert C.

    1993-01-01

    This study presents an analysis of density measurements made using high-resolution accelerometers aboard several space shuttles at altitudes from 60 to 140 km during reentry into the earth's atmosphere. The observed density fluctuations are interpreted in terms of gravity waves and tides and provide evidence of the importance of such motions well into the thermosphere. Height profiles of fractional density variance reveal that wave amplitudes increase at a rate consistent with observations at lower levels up to about 90 km. The rate of amplitude growth decreases at greater heights, however, and appears to cease above about 110 km. Wave amplitudes are nevertheless large at these heights and suggest that gravity waves may play an important role in forcing of the lower thermosphere.

  19. High Altitude Observatory YBJ and ARGO Project

    NASA Astrophysics Data System (ADS)

    Tan, Y.; ARGO Collaboration

    A 5800 m2 RPC (Resistive Plate Chamber) full coverage air shower array is under construction in the YangBaJing Cosmic Ray Observatory, Tibet of China, by the ChinaItaly ARGO Collaboration. YBJ is a large flat grassland with an area 10 × 70 km2 at 4300m altitude, about 90 north west from Lhasa. Its nearby power station, asphalt road to Lhasa, passing railway (will be constructed during the coming 5 years), optical fiber link to the INTERNET, rare snow and other favourable weather conditions are well suitable for setting an Astrophysical Observatory here. The installation of a large area carpet-like detector in this peculiar site will allow one to perform an all-sky and high duty cycle study of high energy gamma rays from 100GeV to 50 TeV as well as accurate measurements on UHE cosmic rays. To insure the stable and uniform working condition of RPCs, a 104 M2 carpet hall was constructed, the RPC installation have be started in it since last November. The natural distribution and daily variation of temperature in the hall, the data concerning the performances of the installed RPCs, have been measured, the results are presented. ce

  20. The Impact of Moderate-Altitude Staging on Pulmonary Arterial Hemodynamics after Ascent to High Altitude

    DTIC Science & Technology

    2010-01-01

    et al., 1956; Sime et al., 1974). The magnitude of the PAP in- crease plays an important role in the development of high altitude pulmonary edema ...implications for travelers to high altitude. High altitude pulmonary edema (HAPE) is an important cause of high altitude morbidity and mortality, and...P., and Oelz O. (1991). Prevention of high-altitude pulmonary edema by nifedipine. N. Engl. J. Med. 325:1284–1289. Beidleman B.A., Fulco C.S., Muza

  1. The effects of high altitude on choice reaction time mean and intra-individual variability: Results of the Edinburgh Altitude Research Expedition of 2008.

    PubMed

    Dykiert, Dominika; Hall, David; van Gemeren, Nikki; Benson, Richard; Der, Geoff; Starr, John M; Deary, Ian J

    2010-05-01

    This study aimed to investigate the effects of high altitude on reaction time (RT) mean and intra-individual variability. Ten students (6 men, 4 women) took a 4-choice RT test and had their vital signs and Lake Louise (LL) score measured on 21 occasions during the Edinburgh Altitude Research Expedition of 2008 to the Western Himalayas (max. altitude 5,565 m). Linear mixed modeling revealed that mean RT was significantly impaired at altitudes above 4,000 m (p < .001), but relatively unaffected below that threshold. An estimated increase in RT between 4,000 and 5,000 m was 15.5 ms, 95% CI [11.1, 19.9]. LL score was related to slower RTs (B = 1.97, 95% CI [0.70, 3.23], p < .01), while number of errors was associated with faster RTs (B = -1.50, 95% CI [-2.60, -0.39], p < .01). There were persistent practice effects in mean RT (B = -2.16, 95% CI [-2.49, -1.83], p < .001. Log-transformed intra-individual variability in RT increased with higher LL scores (B = 0.01801, 95% CI [0.0049, 0.0311], p < .01) and decreased with rising temperature (B = -0.00754, 95% CI [-0.0119, -0.0032], p < .001). However, after controlling for mean RT, these effects were no longer significant. RTs become significantly impaired above a threshold of 4,000 m. Altitude-related changes in RT intra-individual variability were accounted for by mean RT.

  2. MODIS 3 km and 10 km aerosol optical depth for China: Evaluation and comparison

    NASA Astrophysics Data System (ADS)

    He, Qingqing; Zhang, Ming; Huang, Bo; Tong, Xuelian

    2017-03-01

    The recently released Moderate Resolution Imaging Spectrometer (MODIS) Collection 6 introduced a fine scale aerosol optical depth (AOD) distribution, the 3 km product, which is expected to perform well in analyzing aerosols and identifying local air pollution, especially in the severely polluted atmosphere of China. However, few detailed evaluations of regional variations have been conducted. In this paper, we evaluate MODIS 3 km and 10 km AOD products for China against ground-based measurements and compare their performance with respect to spatial and temporal variations. The ground validations indicate that the two products are generally correlated well to ground-based observations. Spatially, the 3 km product slightly outperform the 10 km product in well-developed areas of southern China. Temporally, both products perform worse during spring and summer. Atmospheric clouds and underlying surface are two key factors that influence the accuracy and number of retrievals for both products. The comparison analysis reveals the newly introduced AOD product clearly shows good relationships with the coarse resolution retrievals in spatial and temporal variation but significant differences regarding details. The 3 km AOD product provides better aerosol gradients, more retrievals in bare areas of western China and some spikes of diurnal variation in cloudy days. Seasonal comparisons show the 3 km AOD product is higher than the 10 km product in all seasons, especially during spring and summer. Although the 3 km product for China generally performs slightly worse than the 10 km product, the added information of the MODIS 3 km AOD product shows potential for studying local aerosol characterization, and may facilitate studies of air pollution.

  3. SAGE II aerosol validation - Selected altitude measurements, including particle micromeasurements

    NASA Technical Reports Server (NTRS)

    Oberbeck, Verne R.; Russell, Philip B.; Pueschel, Rudolf F.; Snetsinger, Kenneth G.; Ferry, Guy V.; Livingston, John M.; Rosen, James N.; Osborn, Mary T.; Kritz, Mark A.

    1989-01-01

    The validity of particulate extinction coefficients derived from limb path solar radiance measurements obtained during the Stratospheric Aerosol and Gas Experiment (SAGE) II is tested. The SAGE II measurements are compared with correlative aerosol measurements taken during January 1985, August 1985, and July 1986 with impactors, laser spectrometers, and filter samplers on a U-2 aircraft, an upward pointing lidar on a P-3 aircraft, and balloon-borne optical particle counters. The data for July 29, 1986 are discussed in detail. The aerosol measurements taken on this day at an altitude of 20.5 km produce particulate extinction values which validate the SAGE II values for similar wavelengths.

  4. Rummy high-altitude pressure measurements and analysis

    SciTech Connect

    Banister, J.R.; Hereford, W.V.

    1982-01-01

    Five pressure-measurement canisters equipped with parachutes were deployed from an A7C aircraft on the Rummy test. Their altitudes above Yucca flat were over 8.5 km when the pressure pulse arrived. Three successful measurements were obtained. These time histories showed a more complicated behavior than histories obtained on Pahute Mesa tests because the Rummy event developed double spall closures over a large area. Excellent agreement was obtained between the observed pressure histories and those calculated from surface acceleration measurements. The Yucca Flat terrain was so level that pressure pulses were not appreciably changed or weakened by elevation differences.

  5. The estimation of 550 km x 550 km mean gravity anomalies. [from free atmosphere gravimetry data

    NASA Technical Reports Server (NTRS)

    Williamson, M. R.; Gaposchkin, E. M.

    1975-01-01

    The calculation of 550 km X 550 km mean gravity anomalies from 1 degree X 1 degree mean free-air gravimetry data is discussed. The block estimate procedure developed by Kaula was used, and estimates for 1452 of the 1654 blocks were obtained.

  6. Km3Net Italy - Seafloor network

    NASA Astrophysics Data System (ADS)

    Papaleo, Riccardo

    2016-04-01

    The KM3NeT European project aims to construct a large volume underwater neutrino telescope in the depths of the Mediterranean Sea. INFN and KM3NeT collaboration, thanks to a dedicated funding of 21.000.000 € (PON 2007-2013), are committed to build and deploy the Phase 1 of the telescope, composed of a network of detection units: 8 towers, equipped with single photomultiplier optical modules, and 24 strings, equipped with multi-photomultipliers optical modules. All the towers and strings are connected to the main electro optical cable by means of a network of junction boxes and electro optical interlink cables. Each junction box is an active node able to provide all the necessary power to the detection units and to guarantee the data transmission between the detector and the on-shore control station. The KM3NeT Italia project foresees the realization and the installation of the first part of the deep sea network, composed of three junction boxes, one for the towers and two for the strings. In July 2015, two junction boxes have been deployed and connected to the new cable termination frame installed during the same sea campaign. The third and last one will be installed in November 2015. The status of the deep sea network is presented together with technical details of the project.

  7. Applying WebMining on KM system

    NASA Astrophysics Data System (ADS)

    Shimazu, Keiko; Ozaki, Tomonobu; Furukawa, Koichi

    KM (Knowledge Management) systems have recently been adopted within the realm of enterprise management. On the other hand, data mining technology is widely acknowledged within Information systems' R&D Divisions. Specially, acquisition of meaningful information from Web usage data has become one of the most exciting eras. In this paper, we employ a Web based KM system and propose a framework for applying Web Usage Mining technology to KM data. As it turns out, task duration varies according to different user operations such as referencing a table-of-contents page, down-loading a target file, and writing to a bulletin board. This in turn makes it possible to easily predict the purpose of the user's task. By taking these observations into account, we segmented access log data manually. These results were compared with results abstained by applying the constant interval method. Next, we obtained a segmentation rule of Web access logs by applying a machine-learning algorithm to manually segmented access logs as training data. Then, the newly obtained segmentation rule was compared with other known methods including the time interval method by evaluating their segmentation results in terms of recall and precision rates and it was shown that our rule attained the best results in both measures. Furthermore, the segmented data were fed to an association rule miner and the obtained association rules were utilized to modify the Web structure.

  8. High altitude balloons with ultra thin polyethylene films for scientific observations

    NASA Astrophysics Data System (ADS)

    Nishimura, J.; Saito, Y.; Matsuzaka, Y.; Namiki, M.; Toriumi, M.; Yokota, R.; Yamagami, T.; Hirosawa, H.; Matsushima, K.

    Development of a balloon flying at higher altitude is one of the most attractive trial for the balloon technology. We, the balloon group at the Institute of Space and Astronautical Science (ISAS), have been engaged in the development since 1991. Our concept is to make a light balloon to go higher. We have developed light equipment for house keeping modules and a ultra-thin film with a thickness of only 3.4 μm. Using these equipments and the film, we launched a balloon with a volume of 30,000 m3 to reach the highest altitude of 50.8 km, which is the highest altitude ever reached by Japanese balloons. In this spring, we are going to launch a balloon with a volume of 60,000 m3 , which is expected to make a new record of the balloon altitude. We are going to report the result of the experiment.

  9. Tidally Induced Variations of PMC Altitudes and Ice Water Content Using a Data Assimilation System

    DTIC Science & Technology

    2010-04-01

    69° N ( Andenes , Norway) and 85 235 km geometric altitude in Figure 5. In addition, we performed five short term integrations of the 236 forecast...intercomparison between two approaches to calculating winds and the Andenes data. 251 252 2.2 Ice Particle Trajectories and CARMA 253 254 As noted

  10. Pulmonary Adaptation to High Altitude.

    DTIC Science & Technology

    1982-08-01

    Fluorometric assays of high energy phosphates in respiratory and limb muscles plus a variety of histochemical techniques to more fully describe the...phenomenon--in the form of the critical level of CO2 required to maintain rhythmic breathing during sleep and explains the effect of acute oxygen therapy on...AD-AR140 51.4 PULMONARY ADAPTATION TO HIGH ALTITUDE(U) WISCONSIN i/i UNIV-MADISON J R DEMPSEY AUG 82 DAMD17-77-C-786 UNCLAS51FIED F/G 619 ML

  11. Crystal structure and magnetic properties of Ba-ordered manganites Ln{sub 0.70}Ba{sub 0.30}MnO{sub 3-{delta}} (Ln = Pr, Nd)

    SciTech Connect

    Trukhanov, S. V. Khomchenko, V. A.; Lobanovski, L. S.; Bushinsky, M. V.; Karpinsky, D. V.; Fedotova, V. V.; Troyanchuk, I. O.; Trukhanov, A. V.; Stepin, S. G.; Szymczak, R.; Botez, C. E.; Adair, A.

    2006-09-15

    The structure and magnetic properties of the Ba-ordered state in solid solutions of manganites Ln{sub 0.70}Ba{sub 0.30}MnO{sub 3-{delta}} (Ln = Pr, Nd) with a cation ratio Ln{sup 3+}/Ba{sup 2+} >> 1 are studied experimentally. The samples are obtained by two-stage synthesis. The initial stoichiometric Ba-disordered solid solutions Ln{sub 0.70}Ba{sub 0.30}MnO{sub 3} synthesized in air according to traditional ceramic technology are characterized by the orthorhombic (Imma, Z = 4) perovskite-like unit cell and are ferromagnets with Curie temperatures T{sub C} {approx} 173 and {approx} 143 K for Pr and Nd, respectively. The average size of a crystalline in the initial samples is 5 {mu}m. It is found that annealing of the initial samples in a vacuum of P[O{sub 2}] = 10{sup -4} Pa leads to their separation into three phases: (1) the anion-deficient ordered LnBaMn{sub 2}O{sub 5} phase described by a tetragonal (P4/mmm, Z = 2) perovskite-like unit cell, as well as the phases (2) Ln{sub 2}O{sub 3} (P3-barm1, Z = 1) and (3) MnO (Fm3-barm, Z = 2). Reduction leads to the formation of a nanocomposite with an average crystallite size = 100 nm. Anion-deficient Ba-ordered phases of LnBaMn{sub 2}O{sub 5} exhibit ferrimagnetic properties with Neel temperatures T{sub N} {approx} 113 and {approx}123 K for Pr and Nd, respectively. Annealing of anion-deficient samples in air at a moderate temperature of T = 800{sup o}C does not change the average size of the nanocrystallite, but noticeably alters their phase composition. Stoichiometric nanocomposites consist of two perovskite-like phases: (1) the Ba-deficient ordered stoichiometric phase LnBaMn{sub 2}O{sub 6}, which is described by a tetragonal (P4/mmm, Z = 2) unit cell and has the Curie temperatures T{sub C} {approx} 313 (Pr) and {approx}303 K (Nd), and (2) the Ba-disordered superstoichiometric phase Ln{sub 0.90}Ba{sub 0.10}MnO{sub 3+{delta}}, which is described by an orthorhombic (Imma, Z = 4) unit cell and has Curie

  12. Influence of texture on the switching behavior of Pb(Zr{sub 0.70}Ti{sub 0.30})O{sub 3} sol-gel derived thin films

    SciTech Connect

    Brooks, K.G.; Klissurska, R.D.; Moeckli, P.; Setter, N.

    1997-02-01

    Rhombohedral Pb(Zr{sub 0.70}Ti{sub 0.30})O{sub 3} thin films of four different well-defined textures, namely, (100), (111), and bimodal (110)/(111), and (100)/(111), were prepared by a sol-gel method. The films were characterized in terms of grain size, presence of second phases, surface roughness, columnarity of grains and other microstructural features. The dielectric, ferroelectric, and fatigue properties were investigated, with emphasis on the hysteresis switching characteristics. Results are discussed from the reference point of the allowable spontaneous polarization directions available for the different textures. The values of coercive field, remanent and saturation polarization, and slope of the loop at the coercive field, at saturating fields can be qualitatively explained based on the texture, independent of microstructural differences. The occurrence of surface pyrochlore, however, is observed to affect the functionality of the saturation curves, particularly for the samples of bimodal texture. Shearing of the hysteresis curves of the bimodal films is also attributed to surface microstructural features. The occurrence of nonswitching 71 or 190{degree} domains in the (111) and (110)/(111) textured films is hypothesized based on a comparison with the data from the (100) textured film. Corrected saturation polarization values agree with the spontaneous polarization values of rhombohedral PZT single crystals and published calculated values for rhombohedral PZT ceramics. The fatigue characteristics show increases in the switching component of polarization in the range 10{sup 3}{endash}10{sup 7} bipolar cycles, particularly for the (111) textured sample. Onset of fatigue is observed for all samples between 10{sup 7} and 10{sup 8} switching cycles. {copyright} {ital 1997 Materials Research Society.}

  13. Altitude effects on growth of indigenous children in Oaxaca, Southern Mexico.

    PubMed

    Little, Bertis B; Malina, Robert M; Pena Reyes, Maria Eugenia; Bali Chavez, Guillermo

    2013-09-01

    The effect of altitude of residence on the growth status of 11,454 indigenous school children 6-14 years of age in Oaxaca, southern Mexico, was examined. Indicators of living conditions (human development index [HDI], index of community nutritional risk [INR], index of marginalization [IM], index of relative isolation [II]) were regressed on z-scores for height, weight and BMI, and the residuals were regressed on altitude of residence (km). Independent of other environmental conditions, altitude negatively affected height by approximately -0.07 z-scores per kilometer altitude above sea level. The estimated average decrease in stature was 0.92 cm per kilometer elevation. BMI was significantly increased, 1.2 units per kilometer elevation, consistent with earlier studies of growth status and altitude. In contrast, weight was not affected by altitude of residence. Approximately 36% of the reduction in height and 54% of the increase in BMI were due to altitude effects; the remaining changes in height and BMI were associated with environmental factors reflected in the indices of community well-being considered.

  14. A case study on the possible altitude-dependent effects of collisions on sodium airglow emission

    NASA Astrophysics Data System (ADS)

    Sarkhel, S.; Sekar, R.; Chakrabarty, D.; Sridharan, S.

    2010-10-01

    Simultaneous observations of a narrowband sodium (Na) airglow photometer corresponding to the D2 line in conjunction with a Na lidar from Gadanki (13.5°N, 79.2°E), India, reveal episodic enhancements in Na airglow intensity during 1930-0142 Indian standard time (IST; IST = UT + 5.5 h) on 18-19 March 2007. This variation is drastically different from the average Na airglow intensity variation for that duration during that month. Interestingly, the Na airglow intensity variation is found to be well correlated with the Na atom concentration variation only at 93.6 km during the period 2312-0142 IST, a period closer to the measurement of mesospheric ozone by the Sounding of Atmosphere using Broadband Emission Radiometry (SABER) instrument on board the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite. Moreover, the correlation coefficient is not significant at 88.5 km, where the Na concentration is maximum. Estimations of the altitude profiles of the volume emission rate of Na airglow corresponding to the D2 line using measured parameters during local postmidnight hours reveal that the peak of volume emission rate is different from 93.6 km. It is suggested that the altitude variation in collisional quenching is needed to match the peak altitude of emission to the altitude where correlation between the Na atom concentration and Na airglow intensity is maximum. The fact that the measured atmospheric pressure reduces by a factor of ˜2.5 as altitude changes from 88.5 to 93.6 km supports this proposition. The case study brings out the sensitivity of Na airglow intensity to the altitude dependence of the collisional quenching that eventually affects Na airglow emission.

  15. Lidar Observations of Tropical High-altitude Cirrus Clouds: Results form Dual Wavelength Raman Lidar Measurements During the ALBATROSS Campaign 1996

    NASA Technical Reports Server (NTRS)

    Neuber, R.; Wegener, Alfred; Schrems, O.; McDermid, I. S.

    1997-01-01

    Results from dual wavelength Raman Lidar Observations of tropical high-altitude cirrus clouds are reported. Based on 107 hours of night-time measurements cirrus cloud were present in more than 50% of the observations at latitudes between 23.5 degress S and 23.5 degrees N and altitudes between 11 and 16km.

  16. Lidar Observations of Tropical High-altitude Cirrus Clouds: Results form Dual Wavelength Raman Lidar Measurements During the ALBATROSS Campaign 1996

    NASA Technical Reports Server (NTRS)

    Neuber, R.; Wegener, Alfred; Schrems, O.; McDermid, I. S.

    1997-01-01

    Results from dual wavelength Raman Lidar Observations of tropical high-altitude cirrus clouds are reported. Based on 107 hours of night-time measurements cirrus cloud were present in more than 50% of the observations at latitudes between 23.5 degress S and 23.5 degrees N and altitudes between 11 and 16km.

  17. Magnetospheric plasma studies using data from the dynamics high and low altitude plasma instruments

    NASA Astrophysics Data System (ADS)

    Barfield, J. N.

    1984-05-01

    Plasma measurements made on Dynamics Explorer 1 and 2 spacecraft are providing new information on the altitude dependence of polar-cap plasma populations, their sources, and the acceleration processes they undergo. This study found that the polar-rain electron population apparently exhibits no significant altitude dependence between altitudes of a few hundred to approximately 20,000 km. This result was expected from the magnetosheath-like energy spectrum of the low-altitude polar rain. In this case of the polar wind, a significant velocity increase was theoretically predicted to occur between the two spacecraft altitudes, and this effect was confirmed by DE-1 plasma measurements. A major result of this study of the accelerated polar wind is its significant conic component, which indicates that the ions are heated perpendicularly as they emerge from the polar-cap ionosphere. The gradual decrease in polar-wind energy observed to occur from the cusp across to the nightside polar cap suggests that the perpendicular heating process, probably in cyclotron waves, is most intense near the cusp region. Significant altitude effects are also observed in the plasmas that occupy magnetic flux tubes connected to polar-cap auroral arcs (or theta auroras). At DE-2, typical low-energy (approximately 100 eV) inverted-V electron distributtions are observed. At DE-1 the electron and positive-ion distribution functions are consistent with electrostatic potential drops that are at times below the typical DE-1 altitude of 15,000 to 20,000 km and at times above these altitudes.

  18. Altitude exposures during commercial flight: a reappraisal.

    PubMed

    Hampson, Neil B; Kregenow, David A; Mahoney, Anne M; Kirtland, Steven H; Horan, Kathleen L; Holm, James R; Gerbino, Anthony J

    2013-01-01

    Hypobaric hypoxia during commercial air travel has the potential to cause or worsen hypoxemia in individuals with pre-existing cardiopulmonary compromise. Knowledge of cabin altitude pressures aboard contemporary flights is essential to counseling patients accurately about flying safety. The objective of the study was to measure peak cabin altitudes during U.S. domestic commercial flights on a variety of aircraft. A handheld mountaineering altimeter was carried by the investigators in the plane cabin during commercial air travel and peak cabin altitude measured. The values were then compared between aircraft models, aircraft classes, and distances flown. The average peak cabin altitude on 207 flights aboard 17 different aircraft was 6341 +/- 1813 ft (1933 m +/- 553 m), significantly higher than when measured in a similar fashion in 1988. Peak cabin altitude was significantly higher for flights longer than 750 mi (7085 +/- 801 ft) compared to shorter flights (5160 +/- 2290 ft/1573 +/- 698 m). Cabin altitude increased linearly with flight distance for flights up to 750 mi in length, but was independent of flight distance for flights exceeding 750 mi. Peak cabin altitude was less than 5000 ft (1524 m) in 70% of flights shorter than 500 mi. Peak cabin altitudes greater than 8000 ft (2438 m) were measured on approximately 10% of the total flights. Peak cabin altitude on commercial aircraft flights has risen over time. Cabin altitude is lower with flights of shorter distance. Physicians should take these factors into account when determining an individual's need for supplemental oxygen during commercial air travel.

  19. Altitude Stress During Participation of Medical Congress.

    PubMed

    Kim, Soon Bae; Kim, Jong Sung; Kim, Sang Jun; Cho, Su Hee; Suh, Dae Chul

    2016-09-01

    Medical congresses often held in highlands. We reviewed several medical issues associated with altitude stress especially while physicians have participated medical congress held in high altitude. Altitude stress, also known as an acute mountain sickness (AMS), is caused by acute exposure to low oxygen level at high altitude which is defined as elevations at or above 1,200 m and AMS commonly occurs above 2,500 m. Altitude stress with various symptoms including insomnia can also be experienced in airplane. AMS and drunken state share many common features in symptoms, neurologic manifestations and even show multiple microbleeds in corpus callosum and white matter on MRI. Children are more susceptible to altitude stress than adults. Gradual ascent is the best method for the prevention of altitude stress. Adequate nutrition (mainly carbohydrates) and hydration are recommended. Consumption of alcohol can exacerbate the altitude-induced impairments in judgment and the visual senses and promote psychomotor dysfunction. For prevention or treatment of altitude stress, acetazolamide, phosphodiesterase inhibitors, dexamethasone and erythropoietin are helpful. Altitude stress can be experienced relatively often during participation of medical congress. It is necessary to remind the harmful effect of AMS because it can cause serious permanent organ damage even though the symptoms are negligible in most cases.

  20. ALT space shuttle barometric altimeter altitude analysis

    NASA Technical Reports Server (NTRS)

    Killen, R.

    1978-01-01

    The accuracy was analyzed of the barometric altimeters onboard the space shuttle orbiter. Altitude estimates from the air data systems including the operational instrumentation and the developmental flight instrumentation were obtained for each of the approach and landing test flights. By comparing the barometric altitude estimates to altitudes derived from radar tracking data filtered through a Kalman filter and fully corrected for atmospheric refraction, the errors in the barometric altitudes were shown to be 4 to 5 percent of the Kalman altitudes. By comparing the altitude determined from the true atmosphere derived from weather balloon data to the altitude determined from the U.S. Standard Atmosphere of 1962, it was determined that the assumption of the Standard Atmosphere equations contributes roughly 75 percent of the total error in the baro estimates. After correcting the barometric altitude estimates using an average summer model atmosphere computed for the average latitude of the space shuttle landing sites, the residual error in the altitude estimates was reduced to less than 373 feet. This corresponds to an error of less than 1.5 percent for altitudes above 4000 feet for all flights.

  1. Altitude Stress During Participation of Medical Congress

    PubMed Central

    Kim, Soon Bae; Kim, Jong Sung; Kim, Sang Jun; Cho, Su Hee

    2016-01-01

    Medical congresses often held in highlands. We reviewed several medical issues associated with altitude stress especially while physicians have participated medical congress held in high altitude. Altitude stress, also known as an acute mountain sickness (AMS), is caused by acute exposure to low oxygen level at high altitude which is defined as elevations at or above 1,200 m and AMS commonly occurs above 2,500 m. Altitude stress with various symptoms including insomnia can also be experienced in airplane. AMS and drunken state share many common features in symptoms, neurologic manifestations and even show multiple microbleeds in corpus callosum and white matter on MRI. Children are more susceptible to altitude stress than adults. Gradual ascent is the best method for the prevention of altitude stress. Adequate nutrition (mainly carbohydrates) and hydration are recommended. Consumption of alcohol can exacerbate the altitude-induced impairments in judgment and the visual senses and promote psychomotor dysfunction. For prevention or treatment of altitude stress, acetazolamide, phosphodiesterase inhibitors, dexamethasone and erythropoietin are helpful. Altitude stress can be experienced relatively often during participation of medical congress. It is necessary to remind the harmful effect of AMS because it can cause serious permanent organ damage even though the symptoms are negligible in most cases. PMID:27621942

  2. Rocket Engine Altitude Simulation Technologies

    NASA Technical Reports Server (NTRS)

    Woods, Jody L.; Lansaw, John

    2010-01-01

    John C. Stennis Space Center is embarking on a very ambitious era in its rocket engine propulsion test history. The first new large rocket engine test stand to be built at Stennis Space Center in over 40 years is under construction. The new A3 Test Stand is designed to test very large (294,000 Ibf thrust) cryogenic propellant rocket engines at a simulated altitude of 100,000 feet. A3 Test Stand will have an engine testing chamber where the engine will be fired after the air in the chamber has been evacuated to a pressure at the simulated altitude of less than 0.16 PSIA. This will result in a very unique environment with extremely low pressures inside a very large chamber and ambient pressures outside this chamber. The test chamber is evacuated of air using a 2-stage diffuser / ejector system powered by 5000 lb/sec of steam produced by 27 chemical steam generators. This large amount of power and flow during an engine test will result in a significant acoustic and vibrational environment in and around A3 Test Stand.

  3. High-altitude reconnaissance aircraft

    NASA Technical Reports Server (NTRS)

    Yazdi, Renee Anna

    1991-01-01

    At the equator the ozone layer ranges from 65,000 to 130,000+ ft, which is beyond the capabilities of the ER-2, NASA's current high-altitude reconnaissance aircraft. This project is geared to designing an aircraft that can study the ozone layer. The aircraft must be able to satisfy four mission profiles. The first is a polar mission that ranges from Chile to the South Pole and back to Chile, a total range of 6000 n.m. at 100,000 ft with a 2500-lb payload. The second mission is also a polar mission with a decreased altitude and an increased payload. For the third mission, the aircraft will take off at NASA Ames, cruise at 100,000 ft, and land in Chile. The final mission requires the aircraft to make an excursion to 120,000 ft. All four missions require that a subsonic Mach number be maintained because of constraints imposed by the air sampling equipment. Three aircraft configurations were determined to be the most suitable for meeting the requirements. The performance of each is analyzed to investigate the feasibility of the mission requirements.

  4. Gm and Km allotypes in autoimmune diseases.

    PubMed

    Dugoujon, J M; Guitard, E; Senegas, M T

    1992-01-01

    The associations or linkages between the polymorphisms of the Gm and Km immunoglobulin allotypes and the susceptibility to autoimmune diseases, including diseases with immuno-pathological pathogenesis are reported in this review. These diseases include multiple sclerosis, rheumatoid arthritis, systemic lupus erythematosus, insulin-dependent diabetes mellitus, Crohn's disease, coeliac disease, Graves' disease, atrophic thyroiditis, Hashimoto's thyroiditis, myasthenia gravis, chronic active hepatitis, alopecia areata, uveitis, vitiligo, Turner's syndrome, glomerular nephritis, Berger's disease and idiopathic dilated cardiomyopathy. Immunoglobulin allotypes are described as well as the statistical methods used to analyse the data.

  5. Barometric pressures at extreme altitudes on Mt. Everest: physiological significance.

    PubMed

    West, J B; Lahiri, S; Maret, K H; Peters, R M; Pizzo, C J

    1983-05-01

    Barometric pressures were measured on Mt. Everest from altitudes of 5,400 (base camp) to 8,848 m (summit) during the American Medical Research Expedition to Everest. Measurements at 5,400 m were made with a mercury barometer, and above this most of the pressures were obtained with an accurate crystal-sensor barometer. The mean daily pressures were 400.4 +/- 2.7 (SD) Torr (n = 35) at 5,400 m, 351.0 +/- 1.0 Torr (n = 16) at 6,300 m, 283.6 +/- 1.5 Torr (n = 6) at 8,050 m, and 253.0 Torr (n = 1) at 8,848 m. All these pressures are considerably higher than those predicted from the ICAO Standard Atmosphere. The chief reason is that pressures at altitudes between 2 and 16 km are latitude dependent, being higher near the equator because of the large mass of cold air in the stratosphere of that region. Data from weather balloons show that the pressure at the altitude of the summit of Mt. Everest varies considerably with season, being about 11.5 Torr higher in midsummer than in midwinter. Although the mountain has been climbed without supplementary O2, the very low O2 partial pressure at the summit means that it is at the limit of man's tolerance, and even day-by-day variations in barometric pressure apparently affect maximal O2 uptake.

  6. Intersystem collisional transfer of excitation in low altitude aurora

    NASA Astrophysics Data System (ADS)

    Benesch, W.

    1983-03-01

    The characteristics of auroral optical emission as a function of altitude are exploited as a source of data for the investigation of the intersystem collisional transfer (ICT) of excitation in the nitrogen molecule. The procedure is based on a recently proposed model for the generation of the red lower border of type B auroras as resulting from the effect of the increased collision frequency at lower altitudes on the distribution of population within the excited molecules. In particular, the 85 km turn-on altitude for the red lower border of auroral arcs provides an indicator for the determination of the density and pressure required for the onset of the ICT process at mesopause temperatures. Values are obtained for collision cross sections and rate constants for the coupling of neighboring vibrational levels in adjacent electronic states in nitrogen. The results are compared with the findings of several laboratory studies on similar collisional transfers among nested electronic states. A two-part process is suggested to account for the observed features of intersystem collisional transfer phenomena.

  7. Multiple Peaks in SABER Mesospheric OH Emission Altitude Profiles

    NASA Astrophysics Data System (ADS)

    Rozum, J. C.; Ware, G. A.; Baker, D. J.; Mlynczak, M. G.; Russell, J. M.

    2012-12-01

    Since January 2002, the SABER instrument aboard the TIMED satellite has been performing limb-scan measurements of the altitude distribution of the hydroxyl airglow. The majority of the SABER 1.6 μm and 2.0 μm OH volume emission rate (VER) profiles manifest a single peak at around 90 km, and are roughly gaussian in shape. However, a significant number (approximately 10% in nighttime) of these VER profiles have an irregular characteristic of multiple peaks that are comparable in brightness to the absolute maximum. The origin of these multiple peaks in SABER profiles is currently being studied. Single peak and irregular SABER OH VER profiles are compared with OH VER altitude curves obtained via theoretical vertical distribution models. In addition, we compare SABER profiles with OH VER altitude profiles obtained from rocket-borne radiometric experiments. The techniques of Liu and Shepherd's analysis of double-peaked emission profiles obtained by the Wind Imaging Interferometer (WINDII) using similar scan geometry are applied. The geographical distribution of the SABER nighttime multiple-peak VER profiles in the 1.6 μm and 2.0 μm channels is presented, as are the distributions of these profiles with respect to instrument-scan geometry parameters. It is noted that during the night, multiple peak profiles are more common at equatorial latitudes. A relationship has been found between the geographical distribution of two-peaked profiles and spatial orientation of the SABER instrument's viewing field.

  8. Description of the strategic high-altitude atmospheric radiation code (SHARC). Scientific report, Jan 89-Oct 90

    SciTech Connect

    Duff, J.W.; Sundberg, R.L.; Gruninger, J.H.; Bernstein, L.S.; Robertson, D.C.

    1990-11-27

    The report describes an upgraded version of the strategic high-altitude radiance code, SHARC-2. SHARC calculates atmospheric radiance and transmittance over the 2-40 micrometer spectral region for arbitrary paths within 50 and 300 km altitude, including space viewing. It models radiation due to NLTE (Non-Local Thermodynamic Equilibrium) molecular emissions which are the dominant sources at these altitudes. This new version, which is now ready for distribution, has been upgraded to include a fully integrated auroral model with time-dependent chemistry, extention down to 50 km altitude, and radiation from the minor isotopes of CO2. In addition, there have been numerous internal upgrades to the various modules. These include a Voigt lineshape for the radiative excitation module; embedding of the auroral region into a quiescent atmosphere; and improvements in the radiation transport algorithms.

  9. Twisted light transmission over 143 km.

    PubMed

    Krenn, Mario; Handsteiner, Johannes; Fink, Matthias; Fickler, Robert; Ursin, Rupert; Malik, Mehul; Zeilinger, Anton

    2016-11-29

    Spatial modes of light can potentially carry a vast amount of information, making them promising candidates for both classical and quantum communication. However, the distribution of such modes over large distances remains difficult. Intermodal coupling complicates their use with common fibers, whereas free-space transmission is thought to be strongly influenced by atmospheric turbulence. Here, we show the transmission of orbital angular momentum modes of light over a distance of 143 km between two Canary Islands, which is 50× greater than the maximum distance achieved previously. As a demonstration of the transmission quality, we use superpositions of these modes to encode a short message. At the receiver, an artificial neural network is used for distinguishing between the different twisted light superpositions. The algorithm is able to identify different mode superpositions with an accuracy of more than 80% up to the third mode order and decode the transmitted message with an error rate of 8.33%. Using our data, we estimate that the distribution of orbital angular momentum entanglement over more than 100 km of free space is feasible. Moreover, the quality of our free-space link can be further improved by the use of state-of-the-art adaptive optics systems.

  10. 100 km CEPC parameters and lattice design

    NASA Astrophysics Data System (ADS)

    Wang, D.; Gao, J.; Yu, C. H.; Zhang, Y.; Wang, Y. W.; Su, F.; Y Zhai, J.; Bai, S.; Geng, H. P.; Bian, T. J.; Wang, N.; Cui, X. H.; Zhang, C.; Qin, Q.

    2017-07-01

    The 100km double ring configuration with shared superconducting RF system has been defined as baseline by the circular electron positron collider (CEPC) steering committee. Based on this new scheme, we will get higher luminosity for Higgs (+170%) keeping the beam power in preliminary conceptual design report (Pre-CDR) or to reduce the beam power (19 MW) while keeping same luminosity. CEPC will be compatible with W and Z experiment. The luminosity for Z is designed at the level of 1035 cm-2s-1. The requirement for the energy acceptance of Higgs has been reduced to 1.5% by enlarging the ring to 100 km. The optics of arc and final focus system (FFS) with crab sextupoles has been designed, and also some primary dynamic aperture (DA) results were introduced. Work supported by the National Key Programme for S&T Research and Development (Grant NO. 2016YFA0400400) and the National Natural Science Foundation of China (11505198, 11575218, 11605210 and 11605211).

  11. Twisted light transmission over 143 km

    PubMed Central

    Krenn, Mario; Handsteiner, Johannes; Fink, Matthias; Fickler, Robert; Ursin, Rupert; Zeilinger, Anton

    2016-01-01

    Spatial modes of light can potentially carry a vast amount of information, making them promising candidates for both classical and quantum communication. However, the distribution of such modes over large distances remains difficult. Intermodal coupling complicates their use with common fibers, whereas free-space transmission is thought to be strongly influenced by atmospheric turbulence. Here, we show the transmission of orbital angular momentum modes of light over a distance of 143 km between two Canary Islands, which is 50× greater than the maximum distance achieved previously. As a demonstration of the transmission quality, we use superpositions of these modes to encode a short message. At the receiver, an artificial neural network is used for distinguishing between the different twisted light superpositions. The algorithm is able to identify different mode superpositions with an accuracy of more than 80% up to the third mode order and decode the transmitted message with an error rate of 8.33%. Using our data, we estimate that the distribution of orbital angular momentum entanglement over more than 100 km of free space is feasible. Moreover, the quality of our free-space link can be further improved by the use of state-of-the-art adaptive optics systems. PMID:27856744

  12. Twisted light transmission over 143 km

    NASA Astrophysics Data System (ADS)

    Krenn, Mario; Handsteiner, Johannes; Fink, Matthias; Fickler, Robert; Ursin, Rupert; Malik, Mehul; Zeilinger, Anton

    2016-11-01

    Spatial modes of light can potentially carry a vast amount of information, making them promising candidates for both classical and quantum communication. However, the distribution of such modes over large distances remains difficult. Intermodal coupling complicates their use with common fibers, whereas free-space transmission is thought to be strongly influenced by atmospheric turbulence. Here, we show the transmission of orbital angular momentum modes of light over a distance of 143 km between two Canary Islands, which is 50× greater than the maximum distance achieved previously. As a demonstration of the transmission quality, we use superpositions of these modes to encode a short message. At the receiver, an artificial neural network is used for distinguishing between the different twisted light superpositions. The algorithm is able to identify different mode superpositions with an accuracy of more than 80% up to the third mode order and decode the transmitted message with an error rate of 8.33%. Using our data, we estimate that the distribution of orbital angular momentum entanglement over more than 100 km of free space is feasible. Moreover, the quality of our free-space link can be further improved by the use of state-of-the-art adaptive optics systems.

  13. Global modeling with GEOS-5 from 50-km to 1-km with a single unified GCM

    NASA Astrophysics Data System (ADS)

    Putman, William; Suarez, Max; Molod, Andrea; Barahona, Donifan

    2015-04-01

    The Goddard Earth Observing System model (GEOS-5) of the Global Modeling and Assimilation Office (GMAO) at NASA Goddard Space Flight Center is uniquely designed to adapt to increasing resolution. This supports application of GEOS-5 for decadal scale climate simulation and reanalysis with a horizontal resolution of 50-kilometers (km), high-resolution numerical weather prediction at 25- to 14-km, and global mesoscale modeling at resolutions of 7- to 1.5-km. Resolution-aware parameterizations and dynamics support this diverse portfolio of applications within a single unified GEOS-5 GCM code-base. We will discuss the adaptation of physics parameterizations with increasing resolution. This includes the role of deep convective parameterization, the move to an improved two-moment microphysics scheme, the need for shallow convective parameterization, and the role of non-hydrostatic dynamics and implicit/explicit damping. Parameterization and dynamics evaluation are explored not only in global integrations with GEOS-5 but with radiative convective equilibrium tests that permit the rapid exploration of high-resolution simulations in a smaller doubly periodic Cartesian domain. Simulation results will highlight intercomparisons of model biases in cloud forcing and precipitation from the 30-year 50-km MERRA-2 reanalysis, 50- to 25-km free-running AMIP simulations, a 2-year 7-km global mesoscale simulation, and monthly global simulations at 3.5-km. A global 1.5-km simulation with GEOS-5 highlights our pursuit of truly convection permitting global simulations with GEOS-5. The tuning evaluation for this simulation using doubly periodic radiative convective equilibrium experiments will be discussed.

  14. Sudden Infant Death Syndrome and Residential Altitude

    PubMed Central

    Shore, Supriya; Bandle, Brian; Niermeyer, Susan; Bol, Kirk A.; Khanna, Amber

    2015-01-01

    BACKGROUND: Theories of sudden infant death syndrome (SIDS) suggest hypoxia is a common pathway. Infants living at altitude have evidence of hypoxia; however, the association between SIDS incidence and infant residential altitude has not been well studied. METHODS: We performed a retrospective cohort study by using data from the Colorado birth and death registries from 2007 to 2012. Infant residential altitude was determined by geocoding maternal residential address. Logistic regression was used to determine adjusted association between residential altitude and SIDS. We evaluated the impact of the Back to Sleep campaign across various altitudes in an extended cohort from 1990 to 2012 to assess for interaction between sleep position and altitude. RESULTS: A total of 393 216 infants born between 2007 and 2012 were included in the primary cohort (51.4% boys; mean birth weight 3194 ± 558 g). Overall, 79.6% infants resided at altitude <6000 feet, 18.5% at 6000 to 8000 feet, and 1.9% at >8000 feet. There were no meaningful differences in maternal characteristics across altitude groups. Compared with residence <6000 feet, residence at high altitude (>8000 feet), was associated with an adjusted increased risk of SIDS (odds ratio 2.30; 95% confidence interval 1.01–5.24). Before the Back to Sleep campaign, the incidence of SIDS in Colorado was 1.99/1000 live births and dropped to 0.57/1000 live births after its implementation. The Back to Sleep campaign had similar effect across different altitudes (P = .45). CONCLUSIONS: Residence at high altitude was significantly associated with an increased adjusted risk for SIDS. Impact of the Back to Sleep campaign was similar across various altitudes. PMID:26009621

  15. Sudden infant death syndrome and residential altitude.

    PubMed

    Katz, David; Shore, Supriya; Bandle, Brian; Niermeyer, Susan; Bol, Kirk A; Khanna, Amber

    2015-06-01

    Theories of sudden infant death syndrome (SIDS) suggest hypoxia is a common pathway. Infants living at altitude have evidence of hypoxia; however, the association between SIDS incidence and infant residential altitude has not been well studied. We performed a retrospective cohort study by using data from the Colorado birth and death registries from 2007 to 2012. Infant residential altitude was determined by geocoding maternal residential address. Logistic regression was used to determine adjusted association between residential altitude and SIDS. We evaluated the impact of the Back to Sleep campaign across various altitudes in an extended cohort from 1990 to 2012 to assess for interaction between sleep position and altitude. A total of 393 216 infants born between 2007 and 2012 were included in the primary cohort (51.4% boys; mean birth weight 3194 ± 558 g). Overall, 79.6% infants resided at altitude <6000 feet, 18.5% at 6000 to 8000 feet, and 1.9% at >8000 feet. There were no meaningful differences in maternal characteristics across altitude groups. Compared with residence <6000 feet, residence at high altitude (>8000 feet), was associated with an adjusted increased risk of SIDS (odds ratio 2.30; 95% confidence interval 1.01-5.24). Before the Back to Sleep campaign, the incidence of SIDS in Colorado was 1.99/1000 live births and dropped to 0.57/1000 live births after its implementation. The Back to Sleep campaign had similar effect across different altitudes (P = .45). Residence at high altitude was significantly associated with an increased adjusted risk for SIDS. Impact of the Back to Sleep campaign was similar across various altitudes. Copyright © 2015 by the American Academy of Pediatrics.

  16. Measurement of Altitude in Blind Flying

    NASA Technical Reports Server (NTRS)

    Brombacher, W G

    1934-01-01

    In this note, instruments for measuring altitude and rate of change of altitude in blind flying and landing of aircraft and their performance are discussed. Of those indicating the altitude above ground level, the sonic altimeter is the most promising. Its present bulk, intermittent operation, and more or less unsatisfactory means of indication are serious drawbacks to its use. The sensitive type aneroid altimeter is also discussed and errors in flying at a pressure level and in landing are discussed in detail.

  17. Atomic oxygen between 80 and 120 km: Evidence for a rapid spatial variation in vertical transport near the ionosphere

    NASA Technical Reports Server (NTRS)

    Donahue, T. M.; Wasser, B.

    1977-01-01

    Analysis of OGO-6 OI green line photometer results was carried out for 8 cases when the alignment of the spacecraft was such that local emission rates could be determined below the altitude of maximum emission and down to about 80 km. Results show a variation on a scale of 6 deg to 8 deg in latitude between regions where the emission rate increases rapidly between 90 and 95 km and regions where it increases slowly from 80 km to 95 km. Latitude-altitude maps of iso-emissivity contours and iso-density contours for oxygen concentration are presented. The latter are computed under 3 assumptions concerning excitation mechanisms. Comparisons of the spatial variations of oxygen density with the results of a time dependent theory suggest the regions of strong downward transport alternate on a scale of about 1000 km with regions of weak transport near 90 km. In the first case conversion of O to O3 at night appears to be overwhelmed by downward transport of O.

  18. Theoretical atmospheric transmission in the mid-and far-infrared at four altitudes.

    PubMed

    Traub, W A; Stier, M T

    1976-02-01

    The ir transmission of the terrestrial atmosphere is calculated at four altitudes of interest: Mauna Kea at 4.2 km (2-1000 microm), aircraft at 14 km (5-1000 microm), and balloon at 28 km and 41 km (10-1000 microm). We show both high resolution spectra (0.05 cm(-1)) and broadband averages. The results are intended to serve both as a detailed guide to the interference that is expected from the atmosphere for astronomical spectroscopy and also as an indicator of the relative change in absorption and emission that can be expected at various observing altitudes. One salient result for the spectral region around 100 microm is that the absorption (and emissivity) of the atmosphere drops by a factor of 10 for each increase in altitude of 15 km throughout the aircraft and balloon range; thus balloon-borne astronomical photometry and spectroscopy should both enjoy a considerable advantage over aircraft observations in the 30-300-microm region.

  19. High altitude-induced pituitary apoplexy.

    PubMed

    Brar, Kiraninder Singh; Garg, Mahendra Kumar

    2012-06-01

    Sudden ascent to high altitudes beyond 2,438 m can cause life-threatening complications such as acute mountain sickness and high altitude cerebral and pulmonary oedema. We present a case of pituitary apoplexy in a young man who ascended to high altitude gradually, after proper acclimatisation. He developed headache, nausea, vomiting and persistent hypotension. Magnetic resonance imaging revealed an enlarged pituitary gland with haemorrhage. His hormonal estimation showed acute adrenal insufficiency due to corticotropin deficiency. The patient responded well to conservative medical management with hormonal replacement therapy. This is most likely the first reported case of high altitude-induced pituitary apoplexy in the literature.

  20. Hormonal contraceptives and travel to high altitude.

    PubMed

    Keyes, Linda E

    2015-03-01

    Women frequently ask about the safety and efficacy of using hormonal contraception (HC), either oral contraceptive pills (OC) or other forms, when traveling to high altitude locales. What are the risks and benefits of using HC at high altitude? Does HC affect acclimatization, exercise performance, or occurrence of acute mountain sickness? This article reviews current data regarding the risks and benefits of HC at high altitude, both demonstrated and theoretical, with the aim of helping health care providers to advise women traveling above 2500 meters. Most healthy women can safely use HC when traveling to high altitude, but should be aware of the potential risks and inconveniences.

  1. Change in turbopause altitude at 52 and 70° N

    NASA Astrophysics Data System (ADS)

    Hall, C. M.; Holmen, S. E.; Meek, C. E.; Manson, A. H.; Nozawa, S.

    2015-07-01

    The turbopause is the demarkation between atmospheric mixing by turbulence (below) and molecular diffusion (above). When studying concentrations of trace species in the atmosphere, and particularly long-term change, it may be important to understand processes present, together with their temporal evolution, that may be responsible for redistribution of atmospheric constituents. The general region of transition between turbulent and molecular mixing coincides with the base of the ionosphere, the lower region in which molecular oxygen is dissociated, and, at high latitude in summer, the coldest part of the whole atmosphere. This study updates previous reports of turbopause altitude, extending the time series by half a decade, and thus shedding new light on the nature of change over solar-cycle timescales. Assuming there is no trend in temperature, at 70° N there is evidence for a summer trend of ~ 1.2 km decade-1, but for winter and at 52° N there is no significant evidence for change at all. If the temperature at 90 km is estimated using meteor trail data, it is possible to estimate a cooling rate, which, if applied to the turbopause altitude estimation, fails to alter the trend significantly irrespective of season. While studies of atomic oxygen density, [O], using mid-latitude timeseries dating from 1975, show positive trends which can be explained by a lowering of the turbopause, [O] exhibits negative trends since 2002 that, although at a different latitude, are compatible with the observed increase in turbopause height reported here.

  2. Change in turbopause altitude at 52 and 70° N

    NASA Astrophysics Data System (ADS)

    Hall, Chris M.; Holmen, Silje E.; Meek, Chris E.; Manson, Alan H.; Nozawa, Satonori

    2016-02-01

    The turbopause is the demarcation between atmospheric mixing by turbulence (below) and molecular diffusion (above). When studying concentrations of trace species in the atmosphere, and particularly long-term change, it may be important to understand processes present, together with their temporal evolution that may be responsible for redistribution of atmospheric constituents. The general region of transition between turbulent and molecular mixing coincides with the base of the ionosphere, the lower region in which molecular oxygen is dissociated, and, at high latitude in summer, the coldest part of the whole atmosphere. This study updates previous reports of turbopause altitude, extending the time series by half a decade, and thus shedding new light on the nature of change over solar-cycle timescales. Assuming there is no trend in temperature, at 70° N there is evidence for a summer trend of ˜ 1.6 km decade-1, but for winter and at 52° N there is no significant evidence for change at all. If the temperature at 90 km is estimated using meteor trail data, it is possible to estimate a cooling rate, which, if applied to the turbopause altitude estimation, fails to alter the trend significantly irrespective of season. The observed increase in turbopause height supports a hypothesis of corresponding negative trends in atomic oxygen density, [O]. This supports independent studies of atomic oxygen density, [O], using mid-latitude time series dating from 1975, which show negative trends since 2002.

  3. Radiation Safety Issues in High Altitude Commercial Aircraft

    NASA Technical Reports Server (NTRS)

    Wilson, John W.; Cucinotta, Francis A.; Shinn, Judy L.

    1995-01-01

    The development of a global economy makes the outlook for high speed commercial intercontinental flight feasible, and the development of various configurations operating from 20 to 30 km have been proposed. In addition to the still unresolved issues relating to current commercial operations (12-16 km), the higher dose rates associated with the higher operating altitudes makes il imperative that the uncertainties in the atmospheric radiation environment and the associated health risks be re-examined. Atmospheric radiation associated with the galactic cosmic rays forms a background level which may, under some circumstances, exceed newly recommended allowable exposure limits proposed on the basis of recent evaluations of the A -bomb survivor data (due to increased risk coefficients). These larger risk coefficients, within the context of the methodology for estimating exposure limits, are resulting in exceedingly low estimated allowable exposure limits which may impact even present day flight operations and was the reason for the CEC workshop in Luxembourg (1990). At higher operating altitudes, solar particles events can produce exposures many orders of magnitude above background levels and pose significant health risks to the most sensitive individuals (such as during pregnancy). In this case the appropriate quality factors are undefined, and some evidence exists which indicates that the quality factor for stochastic effects is a substantial underestimate.

  4. Direct simulation of three-dimensional flow about the AFE vehicle at high altitudes

    NASA Technical Reports Server (NTRS)

    Celenligil, M. Cevdet; Moss, James N.; Bird, Graeme A.

    1988-01-01

    Three-dimensional hypersonic rarefied flow about the Aeroassist Flight Experiment (AFE) vehicle was studied using the direct simulation Monte Carlo (DSMC) technique. Results are presented for the transitional flow regime encountered between 120 and 200 km altitudes with a reentry velocity of 9.92 km/s. In the simulations, a five-species reacting real-gas model that accounts for internal energies (rotational and vibrational) is used. The results indicate that the transitional effects are significant even at an altitude of 200 km and influence the overall vehicle aerodynamics. For the cases considered, the aerodynamic coefficients, surface pressures, convective heating, and flow field structure variations with rarefaction effects are presented.

  5. High altitude medicine education in China: exploring a new medical education reform.

    PubMed

    Luo, Yongjun; Luo, Rong; Li, Weiming; Huang, Jianjun; Zhou, Qiquan; Gao, Yuqi

    2012-03-01

    China has the largest plateau in the world, which includes the whole of Tibet, part of Qinghai, Xinjiang, Yunnan, and Sichuan. The plateau area is about 257.2×10(4) km(2), which accounts for about 26.8% of the total area of China. According to data collected in 2006, approximately twelve million people were living at high altitudes, between 2200 to 5200 m high, on the Qinghai-Tibetan Plateau. Therefore, there is a need for medical workers who are trained to treat individuals living at high altitudes. To train undergraduates in high altitude medicine, the College of High Altitude Military Medicine was set up at the Third Military Medical University (TMMU) in Chongqing in 1999. This is the only school to teach high altitude medicine in China. Students at TMMU study natural and social sciences, basic medical sciences, clinical medical sciences, and high altitude medicine. In their 5(th) year, students work as interns at the General Hospital of Tibet Military Command in Lhasa for 3 months, where they receive on-site teaching. The method of on-site teaching is an innovative approach for training in high altitude medicine for undergraduates. Three improvements were implemented during the on-site teaching component of the training program: (1) standardization of the learning progress; (2) integration of formal knowledge with clinical experience; and (3) coaching students to develop habits of inquiry and to engage in ongoing self-improvement to set the stage for lifelong learning. Since the establishment of the innovative training methods in 2001, six classes of high altitude medicine undergraduates, who received on-site teaching, have graduated and achieved encouraging results. This evidence shows that on-site teaching needs to be used more widely in high altitude medicine education.

  6. Tidal winds at mesopause altitudes over Arecibo (18 deg N, 67 deg W), 5-11 April 1989 (AIDA '89)

    NASA Technical Reports Server (NTRS)

    Roper, R. G.; Adams, G. W.; Brosnahan, J. W.

    1993-01-01

    A tidal analysis of the imaging Doppler interferometer scattering point parameter data at upper mesosphere-lower thermosphere altitudes (70-110 km) is presented, on the basis of the procedure developed by Groves (1959), over the interval April 5-11, 1989 at Aercibo as part of Project AIDA. This analysis reveals a typical equatorial easterly circulation, with mean meridional circulation becoming significant only above 96 km. A periodogram analysis shows the diurnal tide to be the most significant feature of the wind field at these altitudes, with zonal amplitudes up to some 50 m/s and meridional amplitudes approximately half this value. The semidiurnal tide is well developed in both zonal and meridional directions only above 96 km. Both 8- and 6-hr components become significant above 100 km, the 6-h component being as strong as both the 24- and 12-h tides at 100 km.

  7. Exhaust emission calibration of two J-58 afterburning turbojet engines at simulated high-altitude, supersonic flight conditions

    NASA Technical Reports Server (NTRS)

    Holdeman, J. D.

    1976-01-01

    Emissions of total oxides of nitrogen, nitric oxide, unburned hydrocarbons, carbon monoxide, and carbon dioxide from two J-58 afterburning turbojet engines at simulated high-altitude flight conditions are reported. Test conditions included flight speeds from Mach 2 to 3 at altitudes from 16.0 to 23.5 km. For each flight condition exhaust measurements were made for four or five power levels, from maximum power without afterburning through maximum afterburning. The data show that exhaust emissions vary with flight speed, altitude, power level, and radial position across the exhaust. Oxides of nitrogen emissions decreased with increasing altitude and increased with increasing flight speed. Oxides of nitrogen emission indices with afterburning were less than half the value without afterburning. Carbon monoxide and hydrocarbon emissions increased with increasing altitude and decreased with increasing flight speed. Emissions of these species were substantially higher with afterburning than without.

  8. Ozone profile intercomparison based on simultaneous observations between 20 and 40 km

    NASA Technical Reports Server (NTRS)

    Aimedieu, P.; Krueger, A. J.; Robbins, D. E.; Simon, P. C.

    1983-01-01

    The vertical distribution of stratospheric ozone has been simultaneously measured by means of five different instruments carried on the same balloon payload. The launches were performed from Gap during the intercomparison campaign conducted in June 1981 in southern France. Data obtained between altitudes of 20 and 40 km are compared and discussed. Vertical profiles deduced from Electrochemical Concentration Cell sondes launched from the same location by small balloons and from short Umkehr measurements made at Mt Chiran (France) are also included in this comparison. Systematic differences of the order of 20 percent between ozone profiles deduced from solar u.v. absorption and in situ techniques are found.

  9. Compilation of atmospheric gas concentration profiles from 0 to 50 km

    NASA Technical Reports Server (NTRS)

    Smith, M. A. H.

    1982-01-01

    A set of 52 atmospheric gas concentration profiles between 0 and 50 km was compiled as a convenient reference data set for calculation of atmospheric infrared absorption or emission signals and for initialization of iterative procedures for retrieval of gas concentrations from measured data. The distributions of volume mixing ratio as a function of altitude generally correspond to typical diurnally averaged, seasonally averaged Northern Hemisphere midlatitude gas concentration profiles. Profiles are given for all gases included in current infrared atmospheric absorption line parameter compilations, and for a number of additional important trace gases.

  10. High-altitude balloon experiment

    NASA Astrophysics Data System (ADS)

    Browning, William M.; Olson, David S.; Keenan, Donald E.

    1999-08-01

    The mission of the HABE is to resolve critical acquisition, tracking, and pointing (ATP) and fire control issues, validate enabling technologies, simulations, and models, and acquire supporting data for future space-based lasers experiments. HABE is integrating components from existing technologies into a payload that can autonomously acquire, track, and point a low power laser at a ballistic missile in its boost phase of flight. For its primary mission the payload will be flown multiple times to an altitude of 85,000 feet above the White Sands Missile Range. From the near-space environment of the balloon flight, HABE will demonstrate the ATP functions required for a space-based laser in a ballistic missile defense role. The HABE platform includes coarse and fine gimbal pointing, IR and visible passive tracking, active fine tracking, internal auto- alignment and boresighting,and precision line-of-sight stabilization functions. This paper presents an overview and status of the HABE program.

  11. Fire Fighting from High Altitude

    NASA Technical Reports Server (NTRS)

    Cobleigh, Brent; Ambrosia, Vince

    2007-01-01

    A viewgraph presentation on high altitude fire fighting is shown. The topics include: 1) Yellowstone Fire - 1988; 2) 2006 Western States Fire Mission Over-View; 3) AMS-Wildfire Scanner; 4) October 24-25 Mission: Yosemite NP and NF; 5) October 24-25 Mission MODIS Overpass; 6) October 24-25 Mission Highlights; 7) October 28-29 Mission Esperanza Fire, California; 8) Response to the Esperanza Fire in Southern California -- Timeline Oct 27-29 2006; 9) October 28-29 Mission Esperanza Fire Altair Flight Routing; 10) October 28-29 Mission Esperanza Fire Altair Over-Flights; 11) October 28-29 Mission Highlights; 12) Results from the Esperanza Fire Response; 13) 2007 Western States Fire Mission; and 14) Western States UAS Fire Mission 2007

  12. Heavy negative ions in Titan's ionosphere: Altitude and latitude dependence

    NASA Astrophysics Data System (ADS)

    Coates, A. J.; Wellbrock, A.; Lewis, G. R.; Jones, G. H.; Young, D. T.; Crary, F. J.; Waite, J. H.

    2009-12-01

    One of the unexpected results of the Cassini mission was the discovery of negative ions at altitudes between 950 and 1400 km in Titan's ionosphere with masses up to 10,000 amu/q [Coates, A.J., Crary, F.J., Lewis, G.R., Young, D.T., Waite Jr., J.H., Sittler Jr., E.C., 2007. Discovery of heavy negative ions in Titan's ionosphere. Geophys. Res. Lett., 34, L22103, doi:10.1029/2007GL030978; Waite Jr., J.H., Young, D. T., Coates, A. J., Crary, F. J., Magee, B. A., Mandt, K. E., Westlake, J. H., 2008. The Source of Heavy Organics and Aerosols in Titan's Atmosphere, submitted to Organic Matter in Space, Proceedings IAU Symposium no. 251]. These ions are detected at low altitudes during Cassini's closest Titan encounters by the Cassini plasma spectrometer (CAPS) electron spectrometer. This result is important as it is indicative of complex hydrocarbon and nitrile chemical processes at work in Titan's high atmosphere. They may play a role in haze formation and ultimately in the formation of heavy particles (tholins), which fall through Titan's atmosphere and build up on the surface. During Cassini's prime mission negative ions were observed on 23 Titan encounters, including 7 in addition to those reported by Coates et al. [Coates, A.J., Crary, F.J., Lewis, G.R., Young, D.T., Waite Jr., J.H., Sittler Jr., E.C., 2007. Discovery of heavy negative ions in Titan's ionosphere. Geophys. Res. Lett., 34, L22103, doi:10.1029/2007GL030978]. Here, we also examine the altitude and latitude dependence of the high-mass negative ions observed in Titan's ionosphere, and we examine the implications of these results. We find that the maximum negative ion mass is higher at low altitude and at high latitudes. We also find a weaker dependence of the maximum mass on solar zenith angle.

  13. Processing techniques for global land 1-km AVHRR data

    USGS Publications Warehouse

    Eidenshink, Jeffery C.; Steinwand, Daniel R.; Wivell, Charles E.; Hollaren, Douglas M.; Meyer, David

    1993-01-01

    The U.S. Geological Survey's (USGS) Earth Resources Observation Systems (EROS) Data Center (EDC) in cooperation with several international science organizations has developed techniques for processing daily Advanced Very High Resolution Radiometer (AVHRR) 1-km data of the entire global land surface. These techniques include orbital stitching, geometric rectification, radiometric calibration, and atmospheric correction. An orbital stitching algorithm was developed to combine consecutive observations acquired along an orbit by ground receiving stations into contiguous half-orbital segments. The geometric rectification process uses an AVHRR satellite model that contains modules for forward mapping, forward terrain correction, and inverse mapping with terrain correction. The correction is accomplished by using the hydrologic features coastlines and lakes from the Digital Chart of the World. These features are rasterized into the satellite projection and are matched to the AVHRR imagery using binary edge correlation techniques. The resulting coefficients are related to six attitude correction parameters: roll, roll rate, pitch, pitch rate, yaw, and altitude. The image can then be precision corrected to a variety of map projections and user-selected image frames. Because the AVHRR lacks onboard calibration for the optical wavelengths, a series of time-variant calibration coefficients derived from vicarious calibration methods and are used to model the degradation profile of the instruments. Reducing atmospheric effects on AVHRR data is important. A method has been develop that will remove the effects of molecular scattering and absorption from clear sky observations, using climatological measurements of ozone. Other methods to remove the effects of water vapor and aerosols are being investigated.

  14. 45-km horizontal-path optical link experiment

    NASA Astrophysics Data System (ADS)

    Biswas, Abhijit; Ceniceros, Juan M.; Novak, Matthew J.; Jeganathan, Muthu; Portillo, Angel; Erickson, David M.; de Pew, Jon; Sanii, B.; Lesh, James R.

    1999-04-01

    Mountain-top to mountain-top optical link experiments have been initiated at JPL, in order to perform a systems level evaluation of optical communications. Progress made so far is reported. The NASA, JPL developed optical communications demonstrator (OCD) is used to transmit a laser signal from Strawberry Peak (SP), located in the San Bernadino mountains of California. This laser beam is received by a 0.6 m aperture telescope at JPL's Table Mountain Facility (TMF), located in Wrightwood, California. The optical link is bi-directional with the TMF telescope transmitting a continuous 4-wave (cw) 780 nm beacon and the OCD sending back an 840 nm, 100 - 500 Mbps pseudo noise (PN) modulated, laser beam. The optical link path is at an average altitude of 2 Km above sea level, covers a range of 46.8 Km and provides an atmospheric channel equivalent to approximately 4 air masses. Average received power measured at either end fall well within the uncertainties predicted by link analysis. The reduction in normalized intensity variance ((sigma) I2) for the 4- beam beacon, compared to each individual beam, at SP, was from approximately 0.68 to 0.22. With some allowance for intra-beam mis-alignment, this is consistent with incoherent averaging. The (sigma) I2 measured at TMF approximately 0.43 plus or minus 0.22 exceeded the expected aperture averaged value of less than 0.1, probably because of beam wander. The focused spot sizes of approximately 162 plus or minus 6 micrometer at the TMF Coude and approximately 64 plus or minus 3 micrometer on the OCD compare to the predicted size range of 52 - 172 micrometer and 57 - 93 micrometer, respectively. This is consistent with 4 - 5 arcsec of atmospheric 'seeing.' The preliminary evaluation of OCD's fine tracking indicates that the uncompensated tracking error is approximately 3.3 (mu) rad compared to approximately 1.7 (mu) rad observed in the laboratory. Fine tracking performance was intermittent, primarily due to beacon fades on the

  15. Wave analysis in the atmosphere of Venus below 100-km altitude, simulated by the LMD Venus GCM

    NASA Astrophysics Data System (ADS)

    Lebonnois, Sébastien; Sugimoto, Norihiko; Gilli, Gabriella

    2016-11-01

    A new simulation of Venus atmospheric circulation obtained with the LMD Venus GCM is described and the simulated wave activity is analyzed. Agreement with observed features of the temperature structure, static stability and zonal wind field is good, such as the presence of a cold polar collar, diurnal and semi-diurnal tides. At the resolution used (96 longitudes × 96 latitudes), a fully developed superrotation is obtained both when the simulation is initialized from rest and from an atmosphere already in superrotation, though winds are still weak below the clouds (roughly half the observed values). The atmospheric waves play a crucial role in the angular momentum budget of the Venus's atmospheric circulation. In the upper cloud, the vertical angular momentum is transported by the diurnal and semi-diurnal tides. Above the cloud base (approximately 1 bar), equatorward transport of angular momentum is done by polar barotropic and mid- to high-latitude baroclinic waves present in the cloud region, with frequencies between 5 and 20 cycles per Venus day (periods between 6 and 23 Earth days). In the middle cloud, just above the convective layer, a Kelvin type wave (period around 7.3 Ed) is present at the equator, as well as a low-latitude Rossby-gravity type wave (period around 16 Ed). Below the clouds, large-scale mid- to high-latitude gravity waves develop and play a significant role in the angular momentum balance.

  16. An innovative rotational Raman lidar to measure the temperature profile from the surface to 30 km altitude

    NASA Astrophysics Data System (ADS)

    Hauchecorne, Alain; Keckhut, Philippe; Mariscal, Jean-François; d'Almeida, Eric; Dahoo, Pierre-Richard; Porteneuve, Jacques

    2016-06-01

    A concept of innovative rotational Raman lidar with daylight measurement capability is proposed to measure the vertical profile of temperature from the ground to the middle stratosphere. The optical filtering is made using a Fabry-Pérot Interferometer with line spacing equal to the line spacing of the Raman spectrum. The detection is made using a linear PMT array operated in photon counting mode. We plan to build a prototype and to test it at the Haute-Provence Observatory lidar facility. to achieve a time resolution permitting the observation of small-scale atmospheric processes playing a role in the troposphere-stratosphere interaction as gravity waves. If successful, this project will open the possibility to consider a Raman space lidar for the global observation of atmospheric temperature profiles.

  17. Ionosphere variations at 700 km altitude observed by the DEMETER satellite during the 29 March 2006 solar eclipse

    NASA Astrophysics Data System (ADS)

    Wang, X.; Berthelier, J. J.; Lebreton, J. P.

    2010-11-01

    We present an experimental and modeling study of the effects of the 29 March 2006 solar eclipse in the topside ionosphere. Measurements of the densities and temperatures of the thermal electrons and ions were provided by instruments aboard the Centre National d'Etudes Spatiales microsatellite DEMETER, which flew over Europe and Africa near the time of maximum solar obscuration. Data from several orbits, either on the same day or on days encompassing the eclipse day, were available to determine a reference state of the ionosphere along the orbit in absence of eclipse. The comparison between this latter and the actual observations along the eclipse orbit reveal a clear thermal effect with a fast drop of about 200 K of the electron and ion temperatures that follows the variations of the solar UV flux in the F region of the ionosphere conjugate to the satellite position. The plasma density decreases by about 30% but with a significant delay and is better correlated with the solar UV flux averaged over the previous 1 to 2 h in the conjugate F region. This delayed and prolonged decrease of density induces an increase of the electron temperature to be higher than the reference ionosphere. We have also performed a modeling of the ionosphere using the SAMI2 code, after having introduced adequate modifications to reproduce fairly realistic eclipse conditions. Applied to the DEMETER conditions of observation, the model reproduces the observations very well. This work shows that the plasma temperature responds very quickly along the magnetic field lines to the variations of the energy available from the photoelectrons while the plasma density variations are controlled by more complex and slower transport processes.

  18. Predicting km-scale shear zone formation

    NASA Astrophysics Data System (ADS)

    Gerbi, Christopher; Culshaw, Nicholas; Shulman, Deborah; Foley, Maura; Marsh, Jeffrey

    2015-04-01

    Because km-scale shear zones play a first-order role in lithospheric kinematics, accurate conceptual and numerical models of orogenic development require predicting when and where they form. Although a strain-based algorithm in the upper crust for weakening due to faulting appears to succeed (e.g., Koons et al., 2010, doi:10.1029/2009TC002463), a comparable general rule for the viscous crust remains unestablished. Here we consider two aspects of the geological argument for a similar algorithm in the viscous regime, namely (1) whether predicting km-scale shear zone development based on a single parameter (such as strain or shear heating) is reasonable; and (2) whether lithologic variability inherent in most orogenic systems precludes a simple predictive rule. A review of tectonically significant shear zones worldwide and more detailed investigations in the Central Gneiss belt of the Ontario segment of the Grenville Province reveals that most km-scale shear zones occur at lithological boundaries and involve mass transfer, but have fairly little else in common. As examples, the relatively flat-lying Twelve Mile Bay shear zone in the western Central Gneiss belt bounds the Parry Sound domain and is likely the product of both localized anatexis and later retrograde hydration with attendant metamorphism. Moderately dipping shear zones in granitoids of the Grenville Front Tectonic Zone apparently resulted from cooperation among several complementary microstructural processes, such as grain size reduction, enhanced diffusion, and a small degree of metamorphic reaction. Localization into shear zones requires the operation of some spatially restricted processes such as stress concentration, metamorphism/fluid access, textural evolution, and thermal perturbation. All of these could be due in part to strain, but not necessarily linearly related to strain. Stress concentrations, such as those that form at rheological boundaries, may be sufficient to nucleate high strain

  19. Galaxy Groups within 3500 km s-1

    NASA Astrophysics Data System (ADS)

    Kourkchi, Ehsan; Tully, R. Brent

    2017-01-01

    We present an algorithm to find nearby galaxy groups within 3,500 km s-1 (~45 Mpc). Our algorithm is based on the direct observed scaling relations that relate luminosity, velocity dispersion and dimensions of groups. Using these scaling relations, in an iterative process, galaxies with almost the same radial velocities and in close angular proximity fall into groups. Since peculiar velocities and Hubble expansion rate are comparable at these local distances, radial velocities are not very good proxies for galaxies distances. Therefore, further manual investigations of the identified groups is inevitable to discard interlopers and/or to resolve confusing cases in crowded regions. The goal of this study is to explore the nature of smallest galaxy groups and to investigate the halo mass function below 8x1012 solar mass.

  20. Altitude Above Sea Level and Body Mass Index as Determinants of Oxygen Saturation in Children: The SON@ Study.

    PubMed

    Gochicoa-Rangel, Laura; Pérez-Padilla, José Rogelio; Rodríguez-Moreno, Luis; Montero-Matamoros, Arturo; Ojeda-Luna, Nancy; Martínez-Carbajal, Gema; Hernández-Raygoza, Roberto; Ruiz-Pedraza, Dolores; Fernández-Plata, María Rosario; Torre-Bouscoulet, Luis

    2015-01-01

    Altitude above sea level and body mass index are well-recognized determinants of oxygen saturation in adult populations; however, the contribution of these factors to oxygen saturation in children is less clear. To explore the contribution of altitude above sea level and body mass index to oxygen saturation in children. A multi-center, cross-sectional study conducted in nine cities in Mexico. Parents signed informed consent forms and completed a health status questionnaire. Height, weight, and pulse oximetry were recorded. We studied 2,200 subjects (52% girls) aged 8.7 ± 3.0 years. Mean body mass index, z-body mass index, and oxygen saturation were 18.1 ± 3.6 kg·m-2, 0.58 ± 1.3, and 95.5 ± 2.4%, respectively. By multiple regression analysis, altitude proved to be the main predictor of oxygen saturation, with non-significant contributions of age, gender, and body mass index. According to quantile regression, the median estimate of oxygen saturation was 98.7 minus 1.7% per km of altitude above sea level, and the oxygen saturation fifth percentile 97.4 minus 2.7% per km of altitude. Altitude was the main determinant of oxygen saturation, which on average decreased 1.7% per km of elevation from a percentage of 98.7 at sea level. In contrast with adults, this study in children found no association between oxygen saturation and obesity or age.

  1. Improved Blocking at 25km Resolution?

    NASA Astrophysics Data System (ADS)

    Schiemann, R.; Demory, M. E.; Mizielinski, M.; Roberts, M.; Shaffrey, L.; Strachan, J.; Vidale, P. L.; Matsueda, M.

    2014-12-01

    It has been suggested that relatively coarse resolution of atmospheric general circulation models (AGCMs) limits their ability to represent mid-latitude blocking. Assessing the role of model resolution for blocking is computationally expensive, as multi-decadal simulations at the desired resolution are necessary for a robust estimation of blocking statistics. Here, we use an ensemble of three atmosphere-only global models for which simulations that fulfil this requirement are available at resolutions of roughly 25km horizontal grid spacing in the mid-latitudes. This corresponds to about a fourfold increase in resolution over the highest-resolution CMIP5 (Coupled Model Intercomparison Project, Phase 5) models. The three models are (i) the ECMWF model (IFS) as used in the project Athena, (ii) the MRI-AGCM 3.2, and (iii) our own HadGEM3-GA3 simulations obtained in the UPSCALE project (UK on PrACE - weather-resolving Simulations of Climate for globAL Environmental risk). We use a two-dimensional blocking index to assess the representation of blocking in these simulations and in three reanalyses (ERA-Interim, ERA-40, MERRA). We evaluate the spatial distribution of climatological blocking frequency, the interannual variability of blocking occurrence as well as the persistence of blocking events. Furthermore, the degree to which blocking biases are associated with mean-state biases is quantified in the different models. We find that the representation of blocking remains very sensitive to atmospheric resolution as the grid spacing is reduced to about 25km. The simulated blocking frequency increases with resolution, mostly so as to reduce the model bias, yet there is considerable variation between the results obtained for different models, seasons, and for the Atlantic and Pacific regions.

  2. Predicted optical performance of the high-altitude balloon experiment (HABE) telescope in an adverse thermal environment

    SciTech Connect

    Akau, R.L.; Givler, R.C.; Eastman, D.R.

    1994-04-01

    The High-Altitude Balloon Experiment (HABE) telescope was designed to operate at an ambient temperature of {minus}55 C and an altitude of 26 km, using a precooled primary mirror. Although at this altitude the air density is only 1.4 percent of the value at sea level, the temperature gradients within the telescope are high enough to deform the optical wavefront. This problem is considerably lessened by precooling the primary mirror to {minus}35 C. This paper describes the application of several codes to determine the range of wavefront deformation during a mission.

  3. Rates of concussion are lower in National Football League games played at higher altitudes.

    PubMed

    Myer, Gregory D; Smith, David; Barber Foss, Kim D; Dicesare, Christopher A; Kiefer, Adam W; Kushner, Adam M; Thomas, Staci M; Sucharew, Heidi; Khoury, Jane C

    2014-03-01

    Retrospective epidemiologic investigation. To investigate the relationship between altitude and concussion rate in the National Football League (NFL). Because of the physiologic responses that occur during acclimatization to altitude, it was hypothesized that games played on fields at a higher altitude would have reduced concussion rates compared to games played on fields at a lower altitude. Recent research indicates that the elevation above sea level at which football games are played may be associated with the likelihood of a concussion in high school football athletes. Data on incident concussions and athlete exposures for the first 16 weeks of the NFL 2012 and 2013 regular seasons were obtained from publicly available web-based sources and used to calculate competition concussion rates for each NFL stadium. Concussion rates were analyzed in relation to game elevation. During the first 16 weeks of the 2012 and 2013 NFL regular seasons, 300 concussions, involving 284 players, were reported (64.3 primary cases per 10,000 game exposures). The odds of a concussion were 30% lower when playing at a higher elevation (equal to or greater than 644 ft [196.3 m] above sea level) compared to a lower elevation (odds ratio = 0.70; 95% confidence interval: 0.53, 0.94). A multivariable generalized linear model controlling for season, week, and clustering of team at home and away confirmed these results, showing that the odds of at least 1 concussion were reduced by 32% in games played at higher elevation. The results of this epidemiological investigation indicate that increased altitude was associated with a reduction in the odds of a sport-related concussion in NFL athletes. The reported relationship of concussion incidence and field elevation should be further investigated, and, if verified, further work will be needed to understand why that relationship exists. Prognosis, level 2c.

  4. High Altitude Illnesses in Hawai‘i

    PubMed Central

    2014-01-01

    High Altitude Headache (HAH), Acute Mountain Sickness (AMS), and High Altitude Cerebral Edema (HACE) are all high altitude related illnesses in order of severity from the mildly symptomatic to the potentially life-threatening. High altitude illnesses occur when travelers ascend to high altitudes too rapidly, which does not allow enough time for the body to adjust. Slow graded ascent to the desired altitude and termination of ascent if AMS symptoms present are keys to illness prevention. Early recognition and rapid intervention of AMS can halt progression to HACE. Pharmacologic prophylaxis with acetazolamide is a proven method of prevention and treatment of high altitude illness. If prevention fails then treatment modalities include supplemental oxygen, supportive therapy, hyperbaric treatment, and dexamethasone. Given the multitude of visitors to the mountains of Hawai‘i, high altitude illness will continue to persist as a prevalent local condition. This paper will emphasize the prevention and early diagnosis of AMS so that the illness does not progress to HACE. PMID:25478293

  5. High-Altitude Electromagnetic Pulse (HEMP) Testing

    DTIC Science & Technology

    2015-07-09

    Final 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE Test Operations Procedure (TOP) 01-2-620A High-Altitude Electromagnetic Pulse (HEMP...planning and execution of testing Army/DOD equipment to determine the effects of Horizontal Component High Altitude Electromagnetic Pulse (HEMP... Electromagnetic Pulse Horizontal Electromagnetic Pulse Advanced Fast Electromagnetic Pulse Nuclear Weapons Effect Testing and Environments 16. SECURITY

  6. Altitude valve for railway suspension control system

    NASA Astrophysics Data System (ADS)

    Zhang, Xuan; Zhang, Lihao; Li, Qingxuan; Chen, WanSong

    2017-09-01

    With the variation of people and material during vehicle service, the gravity of vehicle could be unbalanced. As a result it might cause accident. In order to solve this problem, altitude valve is assembled on board. It can adjust the gravity of vehicle by the intake and outlet progress of the spring in the altitude valve to prevent the tilt of vehicles.

  7. Density Altitude Maps of Iran and Iraq

    DTIC Science & Technology

    1991-05-01

    standard, DA is lower than PA. DA can also be expressed as the altitude in the ICAO standard atmosphere at which a given density occurs. The maps...produced in this study show the altitude in the ICAO standard atmosphere at which surface density occurs.

  8. Feasibility study for rocket ozone measurements in the 50 to 80 km region using a chemiluminescent technique

    NASA Technical Reports Server (NTRS)

    Goodman, P.

    1973-01-01

    A study has been conducted to determine the feasibility of increasing sensitivity for ozone detection. The detection technique employed is the chemiluminescent reaction of ozone with a rhodamine-B impregnated disk. Previously achieved sensitivities are required to be increased by a factor of about 20 to permit measurements at altitudes of 80 km. Sensitivity was increased by using a more sensitive photomultiplier tube, by increasing the gas velocity past the disk, by different disk preparation techniques, and by using reflective coatings in the disk chamber and on the uncoated side of the glass disk. Reflective coatings provided the largest sensitivity increase. The sum of all these changes was a sensitivity increased by an estimated factor of 70, more than sufficient to permit measurement of ambient ozone concentrations at altitudes of 80 km.

  9. A parametric study of dissociation and ionization models at 12 km/sec

    NASA Technical Reports Server (NTRS)

    Mitcheltree, R. A.

    1991-01-01

    Thermochemical nonequilibrium-solution dependence on available models for the chemical reaction rates is examined. Solutions from the Kang and Dunn (1973) reaction-rate set, the Park rate set of 1987, and the Park rate set of 1991 are compared. The blunt-nosed, axisymmetric geometry considered is a 60-deg sphere cone with nose radius of 1.07 m and cicular aft skirt. The nonequilibrium test case is 12 km/sec entry into the earth's atmosphere at 80 km altitude. The model variations are implemented into the Langley aerothermodynamics upwind relaxation algorithm code. While variations in the reaction rates have no effect on the surface pressure distribution and little effect on the convective heating, the effect on degree of ionization and radiative heating can be a factor of three.

  10. Characteristics and Drivers of High-Altitude Ladybird Flight: Insights from Vertical-Looking Entomological Radar

    PubMed Central

    Jeffries, Daniel L.; Chapman, Jason; Roy, Helen E.; Humphries, Stuart; Harrington, Richard; Brown, Peter M. J.; Handley, Lori-J. Lawson

    2013-01-01

    Understanding the characteristics and drivers of dispersal is crucial for predicting population dynamics, particularly in range-shifting species. Studying long-distance dispersal in insects is challenging, but recent advances in entomological radar offer unique insights. We analysed 10 years of radar data collected at Rothamsted Research, U.K., to investigate characteristics (altitude, speed, seasonal and annual trends) and drivers (aphid abundance, air temperature, wind speed and rainfall) of high-altitude flight of the two most abundant U.K. ladybird species (native Coccinella septempunctata and invasive Harmonia axyridis). These species cannot be distinguished in the radar data since their reflectivity signals overlap, and they were therefore analysed together. However, their signals do not overlap with other, abundant insects so we are confident they constitute the overwhelming majority of the analysed data. The target species were detected up to ∼1100 m above ground level, where displacement speeds of up to ∼60 km/h were recorded, however most ladybirds were found between ∼150 and 500 m, and had a mean displacement of 30 km/h. Average flight time was estimated, using tethered flight experiments, to be 36.5 minutes, but flights of up to two hours were observed. Ladybirds are therefore potentially able to travel 18 km in a “typical” high-altitude flight, but up to 120 km if flying at higher altitudes, indicating a high capacity for long-distance dispersal. There were strong seasonal trends in ladybird abundance, with peaks corresponding to the highest temperatures of mid-summer, and warm air temperature was the key driver of ladybird flight. Climatic warming may therefore increase the potential for long-distance dispersal in these species. Low aphid abundance was a second significant factor, highlighting the important role of aphid population dynamics in ladybird dispersal. This research illustrates the utility of radar for studying high-altitude

  11. [High altitude sojourn in lung diseases].

    PubMed

    Braun, P H

    1993-04-01

    Patients with pulmonary diseases and reduced respiratory reserves live 'higher' than healthy persons. Nevertheless, they tolerate staying at medium altitudes ranging between 1500 and 2500 m a.s.l. surprisingly well. In order to establish patients' high-altitude fitness, it is necessary to examine them individually. It is important to differentiate between reversible obstructive and irreversible pulmonary diseases. Despite a drop in arterial oxygen pressure and oxygen saturation, many patients suffering from average obstructive illness feel no discomfort at high altitude and are surprisingly fit. Patients with irreversible pulmonary diseases, pulmonary emphysema or pulmonary fibrosis feel often more comfortable in the mostly drier and cooler mountain air; however, they are physically less fit when compared at lower altitudes. In contrast to the reversible obstructive pulmonary diseases, only slight adaptation is possible. In judging the tolerance to high altitude, one has to consider that a large number of patients suffering from chronic obstructive pulmonary illnesses simultaneously suffer from coronary heart diseases.

  12. Jupiter's High-Altitude Clouds

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The New Horizons Multispectral Visible Imaging Camera (MVIC) snapped this incredibly detailed picture of Jupiter's high-altitude clouds starting at 06:00 Universal Time on February 28, 2007, when the spacecraft was only 2.3 million kilometers (1.4 million miles) from the solar system's largest planet. Features as small as 50 kilometers (30 miles) are visible. The image was taken through a narrow filter centered on a methane absorption band near 890 nanometers, a considerably redder wavelength than what the eye can see. Images taken through this filter preferentially pick out clouds that are relatively high in the sky of this gas giant planet because sunlight at the wavelengths transmitted by the filter is completely absorbed by the methane gas that permeates Jupiter's atmosphere before it can reach the lower clouds.

    The image reveals a range of diverse features. The south pole is capped with a haze of small particles probably created by the precipitation of charged particles into the polar regions during auroral activity. Just north of the cap is a well-formed anticyclonic vortex with rising white thunderheads at its core. Slightly north of the vortex are the tendrils of some rather disorganized storms and more pinpoint-like thunderheads. The dark 'measles' that appear a bit farther north are actually cloud-free regions where light is completely absorbed by the methane gas and essentially disappears from view. The wind action considerably picks up in the equatorial regions where giant plumes are stretched into a long wave pattern. Proceeding north of the equator, cirrus-like clouds are shredded by winds reaching speeds of up to 400 miles per hour, and more pinpoint-like thunderheads are visible. Although some of the famous belt and zone structure of Jupiter's atmosphere is washed out when viewed at this wavelength, the relatively thin North Temperate Belt shows up quite nicely, as does a series of waves just north of the belt. The north polar region of

  13. Jupiter's High-Altitude Clouds

    NASA Technical Reports Server (NTRS)

    2007-01-01

    The New Horizons Multispectral Visible Imaging Camera (MVIC) snapped this incredibly detailed picture of Jupiter's high-altitude clouds starting at 06:00 Universal Time on February 28, 2007, when the spacecraft was only 2.3 million kilometers (1.4 million miles) from the solar system's largest planet. Features as small as 50 kilometers (30 miles) are visible. The image was taken through a narrow filter centered on a methane absorption band near 890 nanometers, a considerably redder wavelength than what the eye can see. Images taken through this filter preferentially pick out clouds that are relatively high in the sky of this gas giant planet because sunlight at the wavelengths transmitted by the filter is completely absorbed by the methane gas that permeates Jupiter's atmosphere before it can reach the lower clouds.

    The image reveals a range of diverse features. The south pole is capped with a haze of small particles probably created by the precipitation of charged particles into the polar regions during auroral activity. Just north of the cap is a well-formed anticyclonic vortex with rising white thunderheads at its core. Slightly north of the vortex are the tendrils of some rather disorganized storms and more pinpoint-like thunderheads. The dark 'measles' that appear a bit farther north are actually cloud-free regions where light is completely absorbed by the methane gas and essentially disappears from view. The wind action considerably picks up in the equatorial regions where giant plumes are stretched into a long wave pattern. Proceeding north of the equator, cirrus-like clouds are shredded by winds reaching speeds of up to 400 miles per hour, and more pinpoint-like thunderheads are visible. Although some of the famous belt and zone structure of Jupiter's atmosphere is washed out when viewed at this wavelength, the relatively thin North Temperate Belt shows up quite nicely, as does a series of waves just north of the belt. The north polar region of

  14. Diving at altitude: from definition to practice.

    PubMed

    Egi, S Murat; Pieri, Massimo; Marroni, Alessandro

    2014-01-01

    Diving above sea level has different motivations for recreational, military, commercial and scientific activities. Despite the apparently wide practice of inland diving, there are three major discrepancies about diving at altitude: threshold elevation that requires changes in sea level procedures; upper altitude limit of the applicability of these modifications; and independent validation of altitude adaptation methods of decompression algorithms. The first problem is solved by converting the normal fluctuation in barometric pressure to an altitude equivalent. Based on the barometric variations recorded from a meteorological center, it is possible to suggest 600 meters as a threshold for classifying a dive as an "altitude" dive. The second problem is solved by proposing the threshold altitude of aviation (2,400 meters) to classify "high" altitude dives. The DAN (Divers Alert Network) Europe diving database (DB) is analyzed to solve the third problem. The database consists of 65,050 dives collected from different dive computers. A total of 1,467 dives were found to be classified as altitude dives. However, by checking the elevation according to the logged geographical coordinates, 1,284 dives were disqualified because the altitude setting had been used as a conservative setting by the dive computer despite the fact that the dive was made at sea level. Furthermore, according to the description put forward in this manuscript, 72 dives were disqualified because the surface level elevation is lower than 600 meters. The number of field data (111 dives) is still very low to use for the validation of any particular method of altitude adaptation concerning decompression algorithms.

  15. Sleep at high altitude: guesses and facts.

    PubMed

    Bloch, Konrad E; Buenzli, Jana C; Latshang, Tsogyal D; Ulrich, Silvia

    2015-12-15

    Lowlanders commonly report a poor sleep quality during the first few nights after arriving at high altitude. Polysomnographic studies reveal that reductions in slow wave sleep are the most consistent altitude-induced changes in sleep structure identified by visual scoring. Quantitative spectral analyses of the sleep electroencephalogram have confirmed an altitude-related reduction in the low-frequency power (0.8-4.6 Hz). Although some studies suggest an increase in arousals from sleep at high altitude, this is not a consistent finding. Whether sleep instability at high altitude is triggered by periodic breathing or vice versa is still uncertain. Overnight changes in slow wave-derived encephalographic measures of neuronal synchronization in healthy subjects were less pronounced at moderately high (2,590 m) compared with low altitude (490 m), and this was associated with a decline in sleep-related memory consolidation. Correspondingly, exacerbation of breathing and sleep disturbances experienced by lowlanders with obstructive sleep apnea during a stay at 2,590 m was associated with poor performance in driving simulator tests. These findings suggest that altitude-related alterations in sleep may adversely affect daytime performance. Despite recent advances in our understanding of sleep at altitude, further research is required to better establish the role of gender and age in alterations of sleep at different altitudes, to determine the influence of acclimatization and of altitude-related illness, and to uncover the characteristics of sleep in highlanders that may serve as a study paradigm of sleep in patients exposed to chronic hypoxia due to cardiorespiratory disease.

  16. Developmental functional adaptation to high altitude: review.

    PubMed

    Frisancho, A Roberto

    2013-01-01

    Various approaches have been used to understand the origins of the functional traits that characterize the Andean high-altitude native. Based on the conceptual framework of developmental functional adaptation which postulates that environmental influences during the period of growth and development have long lasting effects that may be expressed during adulthood, we initiated a series of studies addressed at determining the pattern of physical growth and the contribution of growth and development to the attainment of full functional adaptation to high-altitude of low and high altitude natives living under rural and urban conditions. Current research indicate that: (a) the pattern of growth at high altitude due to limited nutritional resources, physical growth in body size is delayed but growth in lung volumes is accelerated because of hypoxic stress); (b) low-altitude male and female urban natives can attain a full functional adaptation to high altitude by exposure to high-altitude hypoxia during the period of growth and development; (c) both experimental studies on animals and comparative human studies indicate that exposure to high altitude during the period of growth and development results in the attainment of a large residual lung volume; (d) this developmentally acquired enlarged residual lung volume and its associated increase in alveolar area when combined with the increased tissue capillarization and moderate increase in red blood cells and hemoglobin concentration contributes to the successful functional adaptation of the Andean high-altitude native to hypoxia; and (e) any specific genetic traits that are related to the successful functional adaptation of Andean high-altitude natives have yet to be identified.

  17. Teleportation of entanglement over 143 km

    PubMed Central

    Herbst, Thomas; Scheidl, Thomas; Fink, Matthias; Handsteiner, Johannes; Wittmann, Bernhard; Ursin, Rupert; Zeilinger, Anton

    2015-01-01

    As a direct consequence of the no-cloning theorem, the deterministic amplification as in classical communication is impossible for unknown quantum states. This calls for more advanced techniques in a future global quantum network, e.g., for cloud quantum computing. A unique solution is the teleportation of an entangled state, i.e., entanglement swapping, representing the central resource to relay entanglement between distant nodes. Together with entanglement purification and a quantum memory it constitutes a so-called quantum repeater. Since the aforementioned building blocks have been individually demonstrated in laboratory setups only, the applicability of the required technology in real-world scenarios remained to be proven. Here we present a free-space entanglement-swapping experiment between the Canary Islands of La Palma and Tenerife, verifying the presence of quantum entanglement between two previously independent photons separated by 143 km. We obtained an expectation value for the entanglement-witness operator, more than 6 SDs beyond the classical limit. By consecutive generation of the two required photon pairs and space-like separation of the relevant measurement events, we also showed the feasibility of the swapping protocol in a long-distance scenario, where the independence of the nodes is highly demanded. Because our results already allow for efficient implementation of entanglement purification, we anticipate our research to lay the ground for a fully fledged quantum repeater over a realistic high-loss and even turbulent quantum channel. PMID:26578764

  18. Teleportation of entanglement over 143 km.

    PubMed

    Herbst, Thomas; Scheidl, Thomas; Fink, Matthias; Handsteiner, Johannes; Wittmann, Bernhard; Ursin, Rupert; Zeilinger, Anton

    2015-11-17

    As a direct consequence of the no-cloning theorem, the deterministic amplification as in classical communication is impossible for unknown quantum states. This calls for more advanced techniques in a future global quantum network, e.g., for cloud quantum computing. A unique solution is the teleportation of an entangled state, i.e., entanglement swapping, representing the central resource to relay entanglement between distant nodes. Together with entanglement purification and a quantum memory it constitutes a so-called quantum repeater. Since the aforementioned building blocks have been individually demonstrated in laboratory setups only, the applicability of the required technology in real-world scenarios remained to be proven. Here we present a free-space entanglement-swapping experiment between the Canary Islands of La Palma and Tenerife, verifying the presence of quantum entanglement between two previously independent photons separated by 143 km. We obtained an expectation value for the entanglement-witness operator, more than 6 SDs beyond the classical limit. By consecutive generation of the two required photon pairs and space-like separation of the relevant measurement events, we also showed the feasibility of the swapping protocol in a long-distance scenario, where the independence of the nodes is highly demanded. Because our results already allow for efficient implementation of entanglement purification, we anticipate our research to lay the ground for a fully fledged quantum repeater over a realistic high-loss and even turbulent quantum channel.

  19. Application of Multilayer Feedforward Neural Networks to Precipitation Cell-Top Altitude Estimation

    NASA Technical Reports Server (NTRS)

    Spina, Michelle S.; Schwartz, Michael J.; Staelin, David H.; Gasiewski, Albin J.

    1998-01-01

    The use of passive 118-GHz O2 observations of rain cells for precipitation cell-top altitude estimation is demonstrated by using a multilayer feed forward neural network retrieval system. Rain cell observations at 118 GHz were compared with estimates of the cell-top altitude obtained by optical stereoscopy. The observations were made with 2 4 km horizontal spatial resolution by using the Millimeter-wave Temperature Sounder (MTS) scanning spectrometer aboard the NASA ER-2 research aircraft during the Genesis of Atlantic Lows Experiment (GALE) and the COoperative Huntsville Meteorological EXperiment (COHMEX) in 1986. The neural network estimator applied to MTS spectral differences between clouds, and nearby clear air yielded an rms discrepancy of 1.76 km for a combined cumulus, mature, and dissipating cell set and 1.44 km for the cumulus-only set. An improvement in rms discrepancy to 1.36 km was achieved by including additional MTS information on the absolute atmospheric temperature profile. An incremental method for training neural networks was developed that yielded robust results, despite the use of as few as 56 training spectra. Comparison of these results with a nonlinear statistical estimator shows that superior results can be obtained with a neural network retrieval system. Imagery of estimated cell-top altitudes was created from 118-GHz spectral imagery gathered from CAMEX, September through October 1993, and from cyclone Oliver, February 7, 1993.

  20. High altitude syndromes at intermediate altitudes: a pilot study in the Australian Alps.

    PubMed

    Slaney, Graham; Cook, Angus; Weinstein, Philip

    2013-10-01

    Our hypothesis is that symptoms of high altitude syndromes are detectable even at intermediate altitudes, as commonly encountered under Australian conditions (<2500 m above sea level). High altitude medicine has long recognised several syndromes associated with rapid ascent to altitudes above 2500 m, including high altitude pulmonary oedema (HAPE), high altitude cerebral oedema (HACE) and high altitude flatus expulsion (HAFE). Symptoms of high altitude syndromes are of growing concern because of the global trend toward increasing numbers of tourists and workers exposed to both rapid ascent and sustained physical activity at high altitude. However, in Australia, high altitude medicine has almost no profile because of our relatively low altitudes by international standards. Three factors lead us to believe that altitude sickness in Australia deserves more serious consideration: Australia is subject to rapid growth in alpine recreational industries; altitude sickness is highly variable between individuals, and some people do experience symptoms already at 1500 m; and there is potential for an occupational health and safety issue amongst workers. To test this hypothesis we examined the relationship between any high altitude symptoms and a rapid ascent to an intermediate altitude (1800 m) by undertaking an intervention study in a cohort of eight medical clinic staff, conducted during July of the 2012 (Southern Hemisphere) ski season, using self-reporting questionnaires, at Mansfield (316 m above sea level) and at the Ski Resort of Mt Buller (1800 m), Victoria, Australia. The intervention consisted of ascent by car from Mansfield to Mt Buller (approx. 40 min drive). Participants completed a self-reporting questionnaire including demographic data and information on frequency of normal homeostatic processes (fluid intake and output, food intake and output, symptoms including thirst and headaches, and frequency of passing wind or urine). Data were recorded in hourly periods

  1. Effect of altitude on some blood factors and its stability after leaving the altitude.

    PubMed

    Hematy, Yones; Setorki, Mahbubeh; Razavi, Akram; Doudi, Monir

    2014-09-01

    The underlying mechanisms of altitude training are still a matter of controversial discussion. The aim of this study was to compare the hemoglobin concentration, red blood cell count and volume between normal and high altitude situations and their persistence after returning back from higher altitudes. The study population included male students of Ardal Branch, Islamic Azad University. Twelve apparently healthy individual with high level of physical activity, mean age of 22.6 ± 1.50 years were selected through purposive and available sampling method. In this study, blood samples were collected at different time and altitudes in order to compare the changes of Red Blood Cell (RBC), Mean Cell Hemoglobin (MCH), Mean Corpuscular Hemoglobin Concentration (MCHC) and Mean Cell Volume (MCV). The first blood sampling was conducted at the altitude of 1830 m. The subsequent blood samplings were conducted 48 and 72 h after reaching the altitude of 4000 m and 24, 48 and 72 h after returning back to the altitude of 1830 m. The statistical method used in this study was repeated measurement ANOVA. Red Blood Cell (RBC) changes between onset of climbing to 1830 m and 24, 48 and 2 h after sojourn at 1830 m height (after returning from 4000 m altitude) was significant. Mean Cell Hemoglobin (MCH) showed no significant change in any of the altitudes. MCHC changes between onset of moving toward altitude 1830 meters and 24, 48 and 72 h after sojourn at 1830 m height (after returning from 4000 m altitude) was also significant in addition, MCHC showed a significant difference between 24 h staying at 1830 m altitude with 48 and 72 h staying at 4000 m altitude. Mean Cell Volume (MCV) showed no significant difference between 48 and 72 h staying at 4000 m altitude and also between 24, 48 and 72 h staying at 1830 m altitude; however, there was a significant difference between onset of moving toward 1830 m altitude with 24, 48 and 72 h staying at 1830 m altitude and also 48 and 72 h staying at

  2. Development of Ultra-Thin Polyethylene Balloons for High Altitude Research upto Mesosphere

    NASA Astrophysics Data System (ADS)

    Kumar, B. Suneel; Nagendra, N.; Ojha, D. K.; Peter, G. Stalin; Vasudevan, R.; Anand, D.; Kulkarni, P. M.; Reddy, V. Anmi; Rao, T. V.; Sreenivasan, S.

    Ever since its inception four decades back, Balloon Facility of Tata Institute of Fundamental Research (TIFR), Hyderabad has been functioning with the needs of its user scientists at its focus. During the early nineties, when the X-ray astronomy group at TIFR expressed the need for balloons capable of carrying the X-ray telescopes to altitudes up to 42 km, the balloon group initiated research and development work on indigenous balloon grade films in various thickness not only for the main experiment but also in parallel, took up the development of thin films in thickness range 5 to 6 μm for fabrication of sounding balloons required for probing the stratosphere up to 42 km as the regular 2000-gram rubber balloon ascents could not reach altitudes higher than 38 km. By the year 1999, total indigenization of sounding balloon manufacture was accomplished. The work on balloon grade ultra-thin polyethylene film in thickness range 2.8 to 3.8 μm for fabrication of balloons capable of penetrating mesosphere to meet the needs of user scientists working in the area of atmospheric dynamics commenced in 2011. Pursuant to the successful trials with 61,000-m3 balloon made of 3.8-μm Antrix film reaching stratopause (48 km) for the first time in the history of balloon facility in the year 2012, fine tuning of launch parameters like percentage free lift was carried out to take the same volume balloons to higher mesospheric altitudes. Three successful flights with a total suspended load of 10 kg using 61,000-m3 balloons were carried out in the month of January 2014 and all the three balloons crossed into the mesosphere reaching altitudes of over 51 km. All the balloons flown so far are closed system with no escape ducts. Balloon fabrication, development of launch hardware, flight control instruments and launch technique for these mesospheric balloon flights are discussed in this paper.

  3. Relative effects on atmospheric ozone of latitude and altitude of supersonic flight

    NASA Technical Reports Server (NTRS)

    Cunnold, D. M.; Alyea, F. N.; Prinn, R. G.

    1977-01-01

    Three calculations are reported of the potential depletion of ozone by supersonic aircraft. These calculations utilized a two-dimensional model and a three-dimensional photochemical-dynamical model of the atmosphere in which ozone and the dynamical variables of the atmosphere were derived simultaneously. All calculations were based on a continuous atmospheric injection of 1.8 million tons/yr of NO2. Injections of 45 deg N and 20 km, at equilibrium, resulted in a 36% increase in total odd nitrogen between 8 and 38 km and in global ozone depletion of approximately 12%. Injection at 45 deg N and 17 km produced a 27% increase in odd nitrogen, but, because much of this increase occurred below 20 km, the ozone depletion amounted to only 6%. Injection at 10 deg N and 29 km resulted in a 55% increase of odd nitrogen; however, although there was more depletion above 20 km altitude, there was less below that altitude, and the ozone depletion was only 12.5%. In all three calculations, at least half as much ozone depletion occurred in the Southern Hemisphere as in the Northern Hemisphere.

  4. Thermal Structure of the Mesopause Region (80-105 km) at 40°N Latitude. Part II: Diurnal Variations.

    NASA Astrophysics Data System (ADS)

    States, Robert J.; Gardner, Chester S.

    2000-01-01

    Sodium wind/temperature lidar measurements taken throughout the diurnal and annual cycles at Urbana, Illinois (40°N, 88°W), from February 1996 through January 1998 are used to characterize the seasonal behavior of solar thermal tides in the mesopause region between 80 and 105 km. The 24-, 12-, 8-, and 6-h tides are investigated. Between 80 and 92 km the diurnal temperature variation is influenced mainly by in situ heating associated with solar UV absorption by O3 (5 K amplitude at 85 km) and by an upwardly propagating wave originating from tidal sources in the troposphere and stratosphere. Above 100 km, there is also a strong diurnal signature due to in situ heating from solar UV absorption by O2 (3 K amplitude at 102 km). The phase analysis shows this oscillation to be evanescent or downward propagating with maximum amplitude near local noon. The middle region between 92 and 100 km contains very little diurnal variation, which appears to be caused by destructive interference of the direct solar heating, which is maximum during the day with the migrating tidal perturbations and chemical heating (1.5 K amplitude at 96 km), which are both maximum at night. This feature of the diurnal oscillation is prevalent throughout the annual cycle. The diurnal variation is significantly reduced during winter. The Global Scale Wave Model (GSWM) consistently underestimates the diurnal amplitude especially at altitudes below 90 km. The semidiurnal tide is characterized by increasing amplitude with increasing altitude throughout the mesopause region at all times of the year. The GSWM predicts a similar structure, but with a smaller amplitude growth length than the observations reveal. The phase of the 12-h tide is generally downward for all seasons, indicating this component is excited below the mesopause region. The 8- and 6-h tides exhibit consistently small amplitudes (<3 K) below 97 km and sharp amplitude increases above 100 km. An analysis of a mean day averaged over the

  5. Subjective sleep quality alterations at high altitude.

    PubMed

    Szymczak, Robert K; Sitek, Emilia J; Sławek, Jarosław W; Basiński, Andrzej; Siemiński, Mariusz; Wieczorek, Dariusz

    2009-01-01

    Sleep pattern at high altitude has been studied, mainly with the use of polysomnography. This study aimed to analyze subjective sleep quality at high altitude using the following standardized scales: the Pittsburgh Sleep Quality Index (PSQI) and the Athens Insomnia Scale (AIS-8). Thirty-two members of 2 expeditions--28 males and 4 females (mean age 31 years)--participated in this study conducted in Nepal, Himalayas (Lobuche East, 6119 m above sea level [masl]), Kyrgyzstan, Pamirs (Lenin Peak, 7134 masl), and Poland (sea level). The scales were administered twice, at high altitude (mean altitude 4524 masl) and at sea level. Both measures showed a decrease in sleep quality at high altitude (statistical significance, P < .001). Sleep problems affected general sleep quality and sleep induction. Sleep disturbances due to awakenings during the night, temperature-related discomfort, and breathing difficulties were reported. High altitude had no statistically significant effect on sleep duration or daytime dysfunction as measured by PSQI. The overall results of PSQI and AIS-8 confirm the data based on the climbers' subjective accounts and polysomnographic results reported in previous studies. The introduction of standardized methods of subjective sleep quality assessment might resolve the problem of being able to perform precise evaluations and research in the field of sleep disturbances at high altitude.

  6. Carbon monoxide studies at high altitude.

    PubMed

    McGrath, J J

    1988-01-01

    In high altitude areas, ambient carbon monoxide (CO) concentrations are rising because of the increasing number of new residents and tourists, and their concomitant use of motor vehicles and heating appliances. There are, however, comparatively few studies of the acute or chronic physiological effects that may be caused by inhaling CO at high altitude. There are data supporting the concept that the effects of breathing CO at high altitude are additive, and data suggesting that the effects may be more than additive. Visual sensitivity and flicker fusion frequency are reduced in humans inhaling CO at high altitude. One provocative study suggests that the increase in coronary capillarity seen with chronic altitude exposure may be blocked by CO. We exposed male, laboratory rats for 6 weeks to 100 ppm CO, 4676 m (15,000 ft) simulated high altitude (SHA), and CO at SHA. SHA increase hematocrit ratio (Hct) and right ventricle weight, but decreased body weight. CO increased Hct and left ventricle weight. Our results indicate that 100 ppm CO does not exacerbate the effects produced by exposure to 4676 m altitude.

  7. Postnatal cardiopulmonary adaptations to high altitude.

    PubMed

    Huicho, Luis

    2007-09-30

    Postnatal cardiopulmonary adaptations to high altitude constitute a key component of any set of responses developed to face high altitude hypoxia. Such responses are required ultimately to meet the energy demands necessary for adequate functioning at cell and organism level. After a brief insight on general and cardiopulmonary comparative studies in growing and adult organisms, differences and possible explanations for varying cardiopulmonary pathology, pulmonary artery hypertension, persistent right ventricular predominance and subacute high altitude pulmonary hypertension in different populations of children living at high altitude are discussed. Potential long-term implications of early chronic hypoxic exposure on later diseases are also presented. It is hoped that this review will help the practicing physician working at high altitude to make informed decisions concerning individual pediatric patients, specifically with regard to diagnosis and management of altitude-related cardiopulmonary pathology. Finally, plausibility and the knowledge-base of public health interventions to reduce the risks posed by suboptimal or inadequate postnatal cardiopulmonary responses to high altitude are discussed.

  8. [Sildenafil and exercise performance at altitude].

    PubMed

    Peidro, Roberto M

    2015-01-01

    Barometric pressure and partial oxygen pressure decrease with increasing altitude. Hypobaric hypoxia produced is responsible for altitude-related diseases and it can cause severe decrements in exercise performance. The physiological adaptations to the altitude are multiple and they contribute to alter different athletic qualities. The VO2 worsening could be associated to increased pulmonary vascular resistance and nitric oxide diffusion alteration. Performance impairments at altitude can also be accentuated by hypoxia-induced elevations in pulmonary arterial pressure. Clinical studies have demonstrated the beneficial effects of sildenafil on the treatment of pulmonary hypertension. These effects have led to suggest that its indication for competitions at altitude might improve athletic performance. The investigations demonstrate different results depending on the altitude level and times and intensities of exercise. Some studies show performance improvements, although not in all participants. Individual responses vary widely between different athletes. This presentation examines the effects of altitude on exercise capacity and shows studies about the use of sildenafil to improve sport performance. This text also discusses the possible side effects and implications for the use of sildenafil in athletes, indication that is not the basic one of the drug. The physicians must know in each athlete the individual sildenafil side effects that could arise and that would influence negatively on health and performance.

  9. High Altitude Launch for a Practical SSTO

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Denis, Vincent

    2003-01-01

    Existing engineering materials allow the construction of towers to heights of many kilometers. Orbital launch from a high altitude has significant advantages over sea-level launch due to the reduced atmospheric pressure, resulting in lower atmospheric drag on the vehicle and allowing higher rocket engine performance. High-altitude launch sites are particularly advantageous for single-stage to orbit (SSTO) vehicles, where the payload is typically 2 percent of the initial launch mass. An earlier paper enumerated some of the advantages of high altitude launch of SSTO vehicles. In this paper, we calculate launch trajectories for a candidate SSTO vehicle, and calculate the advantage of launch at launch altitudes 5 to 25 kilometer altitudes above sea level. The performance increase can be directly translated into increased payload capability to orbit, ranging from 5 to 20 percent increase in the mass to orbit. For a candidate vehicle with an initial payload fraction of 2 percent of gross lift-off weight, this corresponds to 31 percent increase in payload (for 5-kilometer launch altitude) to 122 percent additional payload (for 25-kilometer launch altitude).

  10. Temperature minima in the average thermal structure of the middle mesosphere (70 - 80 km) from analysis of 40- to 92-km SME global temperature profiles

    NASA Technical Reports Server (NTRS)

    Clancy, R. Todd; Rusch, David W.; Callan, Michael T.

    1994-01-01

    Global temperatures have been derived for the upper stratosphere and mesosphere from analysis of Solar Mesosphere Explorer (SME) limb radiance profiles. The SME temperature represent fixed local time observations at 1400 - 1500 LT, with partial zonal coverage of 3 - 5 longitudes per day over the 1982-1986 period. These new SME temperatures are compared to the COSPAR International Ionosphere Reference Atmosphere 86 (CIRA 86) climatology (Fleming et al., 1990) as well as stratospheric and mesospheric sounder (SAMS); Barnett and Corney, 1984), National Meteorological Center (NMC); (Gelman et al., 1986), and individual lidar and rocket observations. Significant areas of disagreement between the SME and CIRA 86 mesospheric temperatures are 10 K warmer SME temperatures at altitudes above 80 km. The 1981-1982 SAMS temperatures are in much closer agreement with the SME temperatures between 40 and 75 km. Although much of the SME-CIRA 86 disagreement probably stems from the poor vertical resolution of the observations comprising the CIRA 86 modelm, some portion of the differences may reflect 5- to 10-year temporal variations in mesospheric temperatures. The CIRA 86 climatology is based on 1973-1978 measurements. Relatively large (1 K/yr) 5- to 10-year trends in temperatures as functions of longitude, latitude, and altitude have been observed for both the upper stratosphere (Clancy and Rusch, 1989a) and mesosphere (Clancy and Rusch, 1989b; Hauchecorne et al., 1991). The SME temperatures also exhibit enhanced amplitudes for the semiannual oscillation (SAO) of upper mesospheric temperatures at low latitudes, which are not evident in the CIRA 86 climatology. The so-called mesospheric `temperature inversions' at wintertime midlatitudes, which have been observed by ground-based lidar (Hauschecorne et al., 1987) and rocket in situ measurements (Schmidlin, 1976), are shown to be a climatological aspect of the mesosphere, based on the SME observations.

  11. High-Altitude Hydration System

    NASA Technical Reports Server (NTRS)

    Parazynski, Scott E.; Orndoff, Evelyne; Bue, Grant C.; Schaefbauer, Mark E.; Urban, Kase

    2010-01-01

    Three methods are being developed for keeping water from freezing during high-altitude climbs so that mountaineers can remain hydrated. Three strategies have been developed. At the time of this reporting two needed to be tested in the field and one was conceptual. The first method is Passive Thermal Control Using Aerogels. This involves mounting the fluid reservoir of the climber s canteen to an inner layer of clothing for better heat retention. For the field test, bottles were mounted to the inner fleece layer of clothing, and then aerogel insulation was placed on the outside of the bottle, and circumferentially around the drink straw. When climbers need to drink, they can pull up the insulated straw from underneath the down suit, take a sip, and then put it back into the relative warmth of the suit. For the field test, a data logger assessed the temperatures of the water reservoir, as well as near the tip of the drink straw. The second method is Passive Thermal Control with Copper-Shielded Drink Straw and Aerogels, also mounted to inner layers of clothing for better heat retention. Braided wire emanates from the inside of the fleece jacket layer, and continues up and around the drink straw in order to use body heat to keep the system-critical drink straw warm enough to keep water in the liquid state. For the field test, a data logger will be used to compare this with the above concept. The third, and still conceptual, method is Active Thermal Control with Microcontroller. If the above methods do not work, microcontrollers and tape heaters have been identified that could keep the drink straw warm even under extremely cold conditions. Power requirements are not yet determined because the thermal environment inside the down suit relative to the external environment has not been established. A data logger will be used to track both the external and internal temperatures of the suit on a summit day.

  12. Atmospheric drag model for Cassini orbit determination during low altitude Titan flybys

    NASA Technical Reports Server (NTRS)

    Pelletier, F. J.; Antreasian, P. G.; Bordi, J. J.; Criddle, K. E.; Ionasescu, R.; Jacobson, R. A.; Mackenzie, R. A.; Parcher, D. W.; Stauch, J. R.

    2006-01-01

    On April 16, 2005, the Cassini spacecraft performed its lowest altitude flyby of Titan to date, the Titan-5 flyby, flying 1027 km above the surface of Titan. This document discusses the development of a Titan atmospheric drag model for the purpose of the orbit determination of Cassini. Results will be presented for the Titan A flyby, the Titan-5 flyby as well as the most recent low altitude Titan flyby, Titan-7. Different solutions will be compared against OD performance in terms of the flyby B-plane parameters, spacecraft thrusting activity and drag estimates. These low altitude Titan flybys were an excellent opportunity to observe the effect of Titan's atmospheric drag on the orbit determination solution and results show that the drag was successfully modeled to provide accurate flyby solutions.

  13. The distribution of large volcanoes on Venus as a function of height and altitude

    NASA Technical Reports Server (NTRS)

    Keddie, S. T.; Head, J. W.

    1993-01-01

    Theory predicts that the slower cooling of lava flows on Venus should result in lava flows that are typically 20 percent longer than their terrestrial counterparts and that the development of neutral buoyancy zones (NBZ) on Venus may be strongly influenced by altitude-controlled variations in surface pressure. Observations that support these predictions would include relatively low heights for Venus volcanoes, and an increase in both the number and development of large edifices with increasing basal altitude. The results of an analysis of the height and altitude distribution of 123 large (diameter greater than 100 km) volcanoes made using Magellan image and altimetry data are presented and these results are used to begin to test the predications of the above theories.

  14. Daytime ClO over McMurdo in September 1987: Altitude profile retrieval accuracy

    NASA Technical Reports Server (NTRS)

    Barrett, J.; Solomon, P.; Jaramillo, M.; Dezafra, R. L.; Parrish, A.; Emmons, L.

    1988-01-01

    During the 1987 National Ozone Expedition, mm-wave emission line spectra of the 278.6 GHz rotational stratospheric ClO were observed at McMurdo Station, Antarctica. The results confirm the 1986 discovery of a lower stratospheric layer with approximately 100 times the normal amount of ClO; the 1987 observations, made with a spectrometer bandwidth twice that used in 1986, make possible a more accurate retrieval of the altitude profile of the low altitude component of stratospheric ClO from the pressure broadened line shape, down to approximately 16 km. The accuracy of the altitude profile retrievals is discussed, using the daytime (09:30 to 19:30, local time) data from 20 to 24 September, 1987 as an example. The signal strength averaged over this daytime period is approx. 85 percent of the midday peak value. The rate of ozone depletion implied by the observed ClO densities is also discussed.

  15. KM3NeT: towards a km 3-scale neutrino telescope in the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Distefano, C.; KM3NeT Consortium

    2009-05-01

    The observation of high energy neutrinos ( ≳1 TeV) from astrophysical sources would substantially improve our knowledge and understanding of the non-thermal processes in these sources, and would in particular pinpoint the accelerators of cosmic rays. Theoretical predictions indicate that km 3-scale detectors are needed to detect astrophysical neutrino fluxes. That is the reason why the three Mediterranean experiments, ANTARES, NEMO and NESTOR are working together on preparing KM3NeT, a large deep-sea neutrino telescope in the Mediterranean Sea which will survey a large part of the Galactic disc, including the Galactic Centre. It will complement the IceCube telescope currently under construction at the South Pole. Furthermore, the improved optical properties of sea water, compared to Antarctic ice, will allow for a better angular resolution and hence a better background rejection. The construction of this detector will require the solution of technological problems common to many deep submarine installations, and will help paving the way for other deep-sea research facilities. In this paper the major activities and the status of KM3NeT are presented.

  16. KM3NeT: towards a km3-scale neutrino telescope in the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Km3NeT Consortium; Distefano, C.; KM3NeT Consortium

    2009-05-01

    The observation of high energy neutrinos (≳1 TeV) from astrophysical sources would substantially improve our knowledge and understanding of the non-thermal processes in these sources, and would in particular pinpoint the accelerators of cosmic rays. Theoretical predictions indicate that km3-scale detectors are needed to detect astrophysical neutrino fluxes. That is the reason why the three Mediterranean experiments, ANTARES, NEMO and NESTOR are working together on preparing KM3NeT, a large deep-sea neutrino telescope in the Mediterranean Sea which will survey a large part of the Galactic disc, including the Galactic Centre. It will complement the IceCube telescope currently under construction at the South Pole. Furthermore, the improved optical properties of sea water, compared to Antarctic ice, will allow for a better angular resolution and hence a better background rejection. The construction of this detector will require the solution of technological problems common to many deep submarine installations, and will help paving the way for other deep-sea research facilities. In this paper the major activities and the status of KM3NeT are presented.

  17. Some low-altitude cusp dependencies on the interplanetary magnetic field

    NASA Technical Reports Server (NTRS)

    Newell, Patrick T.; Meng, CHING-I.; Sibeck, David G.; Lepping, Ronald

    1989-01-01

    The low-altitude cusp dependencies on the interplanetary magnetic field (IMF) were investigated using the algorithm of Newell and Meng (1988) to identify the cusp proper. The algorithm was applied to 12,569 high-latitude dayside passes of the DMSP F7 spacecraft, and the resulting cusp positioning data were correlated with the IMF. It was found that the cusp latitudinal position correlated reasonably well (0.70) with the Bz component when the IMF had a southward component. The correlation for the northward Bz component was only 0.18, suggestive of a half-wave rectifier effect. The ratio of cusp ion number flux precipitation for Bz southward to that for Bz northward was 1.75 + or - 0.12. The statistical local time widths of the cusp proper for the northward and the southward Bz components were found to be 2.1 h and 2.8 h, respectively.

  18. Evaluation of the CIRA models at low altitude with GOCE densities

    NASA Astrophysics Data System (ADS)

    Bruinsma, S.; Jaeggi, A.; Arnold, D.; sanchez-Ortiz, N.

    2016-12-01

    The CIRA thermosphere specification models JB2008, NRLMSISE-00 and DTM2013 are used to compute satellite drag. Their accuracy at low altitude (180-300 km) is not well documented due to the sparseness of high-resolution and high-accuracy density observations. In the framework of the ESA GOCE+ projects, thermosphere densities were inferred from GOCE observations for the entire Science Mission from November 2009 to 20 October 2013. The exceptional value of the unique low-altitude GOCE density dataset will be demonstrated by comparing it to the CIRA models on long (annual; mission design, lifetime), medium (monthly; solar rotation), and short (daily; re-entry prediction) time scales. The models are evaluated according to the following metric: mean, RMS and standard deviation of the observed-to-modeled ratio (unity for an unbiased model), and correlation. Thanks to GOCE, the models' accuracy at low altitude is established, and analysis of the results reveals the specific weaknesses that require attention in next model revisions. A new ESA General Study (`PREGO') focuses on the last three weeks of the mission, for which a special accelerometer dataset was delivered. The ion propulsion was no longer operating after 20 October and GOCE re-entered the atmosphere over the Falkland Islands on 11 November 2013. The altitude decay rate was very high, but the accelerometers continued to operate up to 8 November, and the GPS receiver up to a day before re-entry. Densities from 230 km to 180 km could be inferred from the accelerometer data. Results of thermosphere model performance for this last part of the GOCE mission will also be presented, and the performance will be compared to results of the Science Mission data at a slightly higher altitude.

  19. Altitude Testing of Large Liquid Propellant Engines

    NASA Technical Reports Server (NTRS)

    Maynard, Bryon; Raines, Nickey

    2008-01-01

    Altitude Testing of the J2-X engine at 100,000 feet (start capability). Chemical Steam Generation for providing vacuum. Project Started Mar 07. Test Stand Activation around Late 2010. J-2X Testing around early 2011.

  20. Paul Bikle's Record Altitude Sailplane Flight

    NASA Image and Video Library

    On a cold and windy February afternoon 50 years ago, the late Paul Bikle, then director of NASA's Flight Research Center, soared into the stratosphere with one goal in mind - a world altitude recor...

  1. High-altitude cerebral oedema mimicking stroke

    PubMed Central

    Yanamandra, Uday; Gupta, Amul; Patyal, Sagarika; Varma, Prem Prakash

    2014-01-01

    High-altitude cerebral oedema (HACO) is the most fatal high-altitude illness seen by rural physicians practising in high-altitude areas. HACO presents clinically with cerebellar ataxia, features of raised intracranial pressure (ICP) and coma. Early identification is important as delay in diagnosis can be fatal. We present two cases of HACO presenting with focal deficits mimicking stroke. The first patient presented with left-sided hemiplegia associated with the rapid deterioration in the sensorium. Neuroimaging revealed features suggestive of vasogenic oedema. The second patient presented with monoplegia of the lower limb. Neuroimaging revealed perfusion deficit in anterior cerebral artery territory. Both patients were managed with dexamethasone and they improved dramatically. Clinical picture and neuroimaging closely resembled acute ischaemic stroke in both cases. Thrombolysis in these patients would have been disastrous. Recent travel to high altitude, young age, absence of atherosclerotic risk factors and features of raised ICP concomitantly directed the diagnosis to HACO. PMID:24671373

  2. 75 FR 52437 - IFR Altitudes; Miscellaneous Amendments

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-26

    ... Federal Aviation Administration 14 CFR Part 95 IFR Altitudes; Miscellaneous Amendments AGENCY: Federal Aviation Administration (FAA), DOT. ACTION: Final rule. SUMMARY: This amendment adopts miscellaneous... Programs Division, Flight Standards Service, Federal Aviation Administration, Mike ] Monroney Aeronautical...

  3. Aeronautic Instruments. Section II : Altitude Instruments

    NASA Technical Reports Server (NTRS)

    Mears, A H; Henrickson, H B; Brombacher, W G

    1923-01-01

    This report is Section two of a series of reports on aeronautic instruments (Technical Report nos. 125 to 132, inclusive). This section discusses briefly barometric altitude determinations, and describes in detail the principal types of altimeters and barographs used in aeronautics during the recent war. This is followed by a discussion of performance requirements for such instruments and an account of the methods of testing developed by the Bureau of Standards. The report concludes with a brief account of the results of recent investigations. For accurate measurements of altitude, reference must also be made to thermometer readings of atmospheric temperature, since the altitude is not fixed by atmospheric pressure alone. This matter is discussed in connection with barometric altitude determination.

  4. The Altitude Effect on Air Speed Indicators

    NASA Technical Reports Server (NTRS)

    Hersey, M D; Hunt, F L; Eaton, H N

    1921-01-01

    The object of this report is to present the results of a theoretical and experimental study of the effect, on the performance of air speed indicators, of the different atmospheric conditions experienced at various altitudes.

  5. Carotidynia in high-altitude travelers.

    PubMed

    Parra, Andrea; Okada, Tamuru; Lin, Peter H

    2017-01-01

    Background Carotidynia is characterized by focal pain and tenderness of the carotid artery without associated hemodynamic or structural abnormalities. Carotid artery pathology has also been known to occur in high altitude due to aberrant baroreceptor response in the carotid bulb. Case Presentation We herein report two cases of high altitude-related idiopathic carotidynia. The first patient was a geologist who performed oil reserve survey in the Alaska Mountain, while the second patient was hiking in a mountain trail in Peru. Both patients developed acute onset of neck pain while traveling in high-altitude mountainous ranges. Carotid imaging showed transmural inflammation surrounding the carotid artery without intraluminal stenosis. Treatment with low-dose aspirin and nonsteroidal anti-inflammatory drug were initiated, which resulted in complete resolution of their symptom. Follow-up carotid ultrasound showed complete resolution of carotid inflammatory tissue density. Discussion This represents the first report linking carotidynia to high-altitude traveling.

  6. On-vehicle emission measurement of a light-duty diesel van at various speeds at high altitude

    NASA Astrophysics Data System (ADS)

    Wang, Xin; Yin, Hang; Ge, Yunshan; Yu, Linxiao; Xu, Zhenxian; Yu, Chenglei; Shi, Xuejiao; Liu, Hongkun

    2013-12-01

    As part of the research on the relationship between the speed of a vehicle operating at high altitude and its contaminant emissions, an on-vehicle emission measurement of a light-duty diesel van at the altitudes of 1000 m, 2400 m and 3200 m was conducted. The test vehicle was a 2.8 L turbocharged diesel Ford Transit. Its settings were consistent in all experiments. Regulated gaseous emissions, including CO, HC and NOx, together with particulate matter was measured at nine speeds ranged from 10 km h-1 to 90 km h-1 with 10 km h-1 intervals settings. At each speed, measurement lasted for at least 120 s to ensure the sufficiency and reliability of the collected data. The results demonstrated that at all altitudes, CO and HC emissions decreased as the vehicle speed increased. However both NOx and PM increased with vehicle speed. In terms of the effects of altitude, an increase in CO, HC and PM was observed with the rising of altitude at each vehicle speed. NOx behaved different: emission of NOx initially increased as the vehicle was raised from 1000 m to 2400 m, but it decreased when the vehicle was further elevated to 3200 m.

  7. NGC 1252: a high altitude, metal poor open cluster remnant

    NASA Astrophysics Data System (ADS)

    de la Fuente Marcos, R.; de la Fuente Marcos, C.; Moni Bidin, C.; Carraro, G.; Costa, E.

    2013-09-01

    If stars form in clusters but most stars belong to the field, understanding the details of the transition from the former to the latter is imperative to explain the observational properties of the field. Aging open clusters are one of the sources of field stars. The disruption rate of open clusters slows down with age but, as an object gets older, the distinction between the remaining cluster or open cluster remnant (OCR) and the surrounding field becomes less and less obvious. As a result, finding good OCR candidates or confirming the OCR nature of some of the best candidates still remain elusive. One of these objects is NGC 1252, a scattered group of about 20 stars in Horologium. Here we use new wide-field photometry in the UBVI passbands, proper motions from the Yale/San Juan SPM 4.0 catalogue and high-resolution spectroscopy concurrently with results from N-body simulations to decipher NGC 1252's enigmatic character. Spectroscopy shows that most of the brightest stars in the studied area are chemically, kinematically and spatially unrelated to each other. However, after analysing proper motions, we find one relevant kinematic group. This sparse object is relatively close (˜1 kpc), metal poor and is probably not only one of the oldest clusters (3 Gyr) within 1.5 kpc from the Sun but also one of the clusters located farthest from the disc, at an altitude of nearly -900 pc. That makes NGC 1252 the first open cluster that can be truly considered a high Galactic altitude OCR: an unusual object that may hint at a star formation event induced on a high Galactic altitude gas cloud. We also conclude that the variable TW Horologii and the blue straggler candidate HD 20286 are unlikely to be part of NGC 1252. NGC 1252 17 is identified as an unrelated, Population II cannonball star moving at about 400 km s-1.

  8. Python Engine Installed in Altitude Wind Tunnel

    NASA Technical Reports Server (NTRS)

    1949-01-01

    An engine mechanic checks instrumentation prior to an investigation of engine operating characteristics and thrust control of a large turboprop engine with counter-rotating propellers under high-altitude flight conditions in the 20-foot-dianieter test section of the Altitude Wind Tunnel at the Lewis Flight Propulsion Laboratory of the National Advisory Committee for Aeronautics, Cleveland, Ohio, now known as the John H. Glenn Research Center at Lewis Field.

  9. High altitude medicine for family physicians.

    PubMed Central

    McMurray, S. J.

    1994-01-01

    High altitude medicine deals with a continuum of diseases ranging from a mild discomfort to serious ailments affecting all organ systems, including the lungs, brain, and eyes. Decreased oxygen tension is the primary cause. The main principles of prevention are staging and graded ascent to allow acclimatization. Adventure travel to high altitude destinations is becoming increasingly popular; family physicians should be informed of the medical problems associated with such travel. Images p712-a p715-a p716-a PMID:8199523

  10. High altitude color photography as a tool for regional analysis: As demonstrated for southeastern Florida

    NASA Technical Reports Server (NTRS)

    Eyre, L. A.

    1972-01-01

    High altitude color and color infrared photography of the tri-county region of southeast Florida made it feasible to evaluate its potential for quantifying the dimensions of regional change. Attention was focused upon three main aspects of change in the region, which in fact overlap. These were; (1) the transformation of the southeast Florida wetlands; (2) the expansion of agriculture; and (3) the growth of the urbanized area. The development analyzed covered the period of thirteen years from 1956 to 1969. Results using this new 18 km photography were superior because of the degree of resolution, the combined power of color and color infrared interpretation, and the large area covered by each frame. The greatest advantage of high altitude imagery is the time-saving element, since it is possible to delineate and identify major geographic patterns over thousands of sq km very rapidly.

  11. The source altitude, electric current, and intrinsic brightness of terrestrial gamma ray flashes

    NASA Astrophysics Data System (ADS)

    Cummer, Steven A.; Briggs, Michael S.; Dwyer, Joseph R.; Xiong, Shaolin; Connaughton, Valerie; Fishman, Gerald J.; Lu, Gaopeng; Lyu, Fanchao; Solanki, Rahulkumar

    2014-12-01

    Many details of how thunderstorms generate terrestrial gamma ray flashes (TGFs) and other forms of high-energy radiation remain uncertain, including the basic question of where they are produced. We exploit the association of distinct low-frequency radio emissions with generation of terrestrial gamma ray flashes (TGFs) to directly measure for the first time the TGF source altitude. Analysis of two events reveals source altitudes of 11.8 ± 0.4 km and 11.9 ± 0.9 km. This places the source region in the interior of the thunderstorm between the two main charge layers and implies an intrinsic TGF brightness of approximately 1018 runaway electrons. The electric current in this nontraditional lightning process is found to be strong enough to drive nonlinear effects in the ionosphere, and in one case is comparable to the highest peak current lightning processes on the planet.

  12. Altitude profiles of O2 on Mars from SPICAM stellar occultations

    NASA Astrophysics Data System (ADS)

    Sandel, B. R.; Gröller, H.; Yelle, R. V.; Koskinen, T.; Lewis, N. K.; Bertaux, J.-L.; Montmessin, F.; Quémerais, E.

    2015-05-01

    We determine the first altitude profiles of O2 in the important photochemical region below 120 km in the atmosphere of Mars by analyzing Mars Express/SPICAM ultraviolet observations of six occultations of stars by the atmosphere. Over the range of 90-130 km the altitude-averaged mixing ratio of O2 relative to the major constituent CO2 varies in space and time in the range of 3.1 ×10-3 - 5.8 ×10-3 , with a mean value of 4.0 ×10-3 . This mean value exceeds by a factor of 3-4 those reported earlier for the lower atmosphere. However, some of the O2 abundance and mixing ratio profiles determined here are similar to those measured by Viking in 1976 in the upper atmosphere.

  13. Laboratory evaluation of an airborne ozone instrument that compensates for altitude/sensitivity effects

    NASA Technical Reports Server (NTRS)

    Gregory, G. L.; Hudgins, C. H.; Edahl, R. A., Jr.

    1983-01-01

    One problem encountered in the use of air-quality instrumentation on aircraft is the variation of instrument sensitivity with pressure as the result of altitude changes of the aircraft. Many instruments experience sensitivity changes of as much as a factor of 2 at altitudes of 6 km. Discussed are recent modifications to a chemiluminescent (ethylene) ozone detector that allow the instrument to automatically compensate for pressure/sensitivity effects. The modification provides automated mass flow rate control for both the sample and ethylene gas flows. The flow control systems maintain flow rate to within 15 percent for a 100-torr instantaneous pressure change, and flow rates are returned to the desired set points within 10 s after the pressure change. During simulated altitude changes (300 m/min from mean sea level to 3-km altitude), flow rates were controlled to within 3 percent of the set point. Laboratory data are summarized verifying the operation of the instrument for a pressure range of 760 torr (sea level) to 350 torr (approximately 20,000 ft) and an ozone concentration range from 20 to approximately 700 ppb.

  14. Anisotropic fluid modeling of ionospheric upflow: Effects of low-altitude anisotropy and thermospheric winds

    NASA Astrophysics Data System (ADS)

    Burleigh, M.; Zettergren, M.

    2017-01-01

    A new anisotropic fluid model is developed to describe ionospheric upflow responses to magnetospheric forcing by electric fields and broadband ELF waves at altitudes of 90-2500 km. This model is based on a bi-Maxwellian ion distribution and solves time-dependent, nonlinear equations of conservation of mass, momentum, parallel energy, and perpendicular energy for six ion species important to E, F, and topside ionospheric regions. It includes chemical and collisional interactions with the neutral atmosphere, photoionization, and electron impact ionization. This model is used to examine differences between isotropic and anisotropic descriptions of ionospheric upflow driven by DC electric fields, possible effects of low-altitude (<500 km) wave heating, and impacts of neutral winds on ion upflow. Results indicate that isotropic models may overestimate field-aligned ion velocity responses by as much as ˜48%. Simulations also show significant ionospheric responses at low altitudes to wave heating for very large power spectral densities, but ion temperature anisotropies below the F region peak are dominated by frictional heating from DC electric fields. Neutral winds are shown to play an important role regulating ion upflow. Thermospheric winds can enhance or suppress upward fluxes driven by DC and BBELF fields by 10-20% for the cases examined. The time history of the neutral winds also affects the amount of ionization transported to higher altitudes by DC electric fields.

  15. Gas physics environment of high altitude Jovian entry.

    NASA Technical Reports Server (NTRS)

    Lefferdo, J. M.; Edquist, C. T.; Steel, P. C.

    1972-01-01

    A description of the gas physics environment associated with high-altitude Jupiter entry is reported. Two aspects of environmental analysis are treated. First, limited discussion is devoted to prediction of the heating environment of the probe aeroshell. Prime emphasis is given to the second aspect of the analysis, a description of the gas particle probe interaction phenomena in the rarefied flow regime. Several molecular reemission models have been devised and exercised. Model selection was based upon the desire to bracket the expected reemission characteristics. Consideration was given to examining diffuse reflection as exemplified by the Maxwellian model and lobular, specular reflection as characterized by the Nocilla model. Variation of fundamental input parameters was investigated to determine particle-probe interaction sensitivity. Regardless of neutral species type, results show that the attenuation of the incoming flux of that species by reflected particles is approximately 15 per cent in the stagnation region at 200 km above the cloud tops.

  16. A nominal set of high-altitude EMP environments

    SciTech Connect

    Longmire, C.L.; Hamilton, R.M.; Hahn, J.M.

    1987-02-01

    This report presents high-altitude EMP (HEMP) environments calculated by the CHAP code for a nominal large yield burst at 400 km over the central US. Nominal, unclassified weapon output parameters were used, along with unclassified EMP theory and calculational techniques. While the resulting environments do not represent upper bounds, they should be useful in developing understanding of the effect of HEMP on electrical and electronic systems. The calculated environments illustrate the wide variability of the HEMP from a single burst, depending on ground range and azimuth from ground zero. Analytic fits to the HEMP fields are provided to facilitate coupling calculations. The CHAP results are justified by a detailed examination of Compton currents, air conductivities, and the resulting fields. It is shown that both HEMP theory and the calculations conserve energy scrupulously.

  17. Passive microwave observations of thunderstorms from high-altitude aircraft

    NASA Technical Reports Server (NTRS)

    Heymsfield, Gerald M.; Fulton, Richard

    1988-01-01

    A high-altitude (20 km) aircraft made overflights of severe and nonsevere Midwest thunderstorms in the central and southeast U.S. during 2 separate experiments. Down-looking instruments on the aircraft are the imaging Multi-Channel Cloud Radiometer with channels in the visible, IR, and near IR, and two passive microwave instruments, the imaging Advanced Microwave Moisture Sounder at 92 (atmospheric window) and 183 GHz (centered on a water vapor line) and the 45 deg foward-of-nadir Multi-Channel Precipitation Radiometer at the 18 and 37 GHz window channels. Over land, the 92 GHz frequency distinguishes quite well the precipitating region from the nonprecipitating anvil region. The interpretation of the microwave measurements is complicated by differences in the cloud microphysics between different climatic regions.

  18. High resolution spectroscopy from low altitude satellites. [gamma ray astronomy

    NASA Technical Reports Server (NTRS)

    Nakano, G. H.; Imhof, W. L.

    1978-01-01

    The P 78 1 satellite to be placed in a synchronous polar orbit at an altitude of 550-660 km will carry two identical high resolution spectrometers each consisting of a single (approximately 85 cc) intrinsic germanium IGE detector. The payload also includes a pair of phoswitch scintillators, an array of CdTe detectors and several particle detectors, all of which are mounted on the wheel of the satellite. The intrinsic high purity IGE detectors receive cooling from two Stirling cycle refrigerators and facilitate the assembly of large and complex detector arrays planned for the next generation of high sensitivity instruments such as those planned for the gamma ray observatory. The major subsystems of the spectrometer are discussed as well as its capabilities.

  19. Early history of high-altitude physiology.

    PubMed

    West, John B

    2016-02-01

    High-altitude physiology can be said to have begun in 1644 when Torricelli described the first mercury barometer and wrote the immortal words "We live submerged at the bottom of an ocean of the element air." Interestingly, the notion of atmospheric pressure had eluded his teacher, the great Galileo. Blaise Pascal was responsible for describing the fall in pressure with increasing altitude, and Otto von Guericke gave a dramatic demonstration of the enormous force that could be developed by atmospheric pressure. Robert Boyle learned of Guericke's experiment and, with Robert Hooke, constructed the first air pump that allowed small animals to be exposed to a low pressure. Hooke also constructed a small low-pressure chamber and exposed himself to a simulated altitude of about 2400 meters. With the advent of ballooning, humans were rapidly exposed to very low pressures, sometimes with tragic results. For example, the French balloon, Zénith, rose to over 8000 m, and two of the three aeronauts succumbed to the hypoxia. Paul Bert was the first person to clearly state that the deleterious effects of high altitude were caused by the low partial pressure of oxygen (PO2), and later research was accelerated by high-altitude stations and expeditions to high altitude.

  20. Airborne Doppler radar detection of low altitude windshear

    NASA Technical Reports Server (NTRS)

    Bracalente, Emedio M.; Jones, William R.; Britt, Charles L.

    1990-01-01

    As part of an integrated windshear program, the Federal Aviation Administration, jointly with NASA, is sponsoring a research effort to develop airborne sensor technology for the detection of low altitude windshear during aircraft take-off and landing. One sensor being considered is microwave Doppler radar operating at X-band or above. Using a Microburst/Clutter/Radar simulation program, a preliminary feasibility study was conducted to assess the performance of Doppler radars for this application. Preliminary results from this study are presented. Analysis show, that using bin-to-bin Automatic Gain Control (AGC), clutter filtering, limited detection range, and suitable antenna tilt management, windshear from a wet microburst can be accurately detected 10 to 65 seconds (.75 to 5 km) in front of the aircraft. Although a performance improvement can be obtained at higher frequency, the baseline X-band system that was simulated detected the presence of a windshear hazard for the dry microburst. Although this study indicates the feasibility of using an airborne Doppler radar to detect low altitude microburst windshear, further detailed studies, including future flight experiments, will be required to completely characterize the capabilities and limitations.

  1. SAGE II aerosol validation: selected altitude measurements, including particle micromeasurements.

    PubMed

    Oberbeck, V R; Livingston, J M; Russell, P B; Pueschel, R F; Rosen, J N; Osborn, M T; Kritz, M A; Snetsinger, K G; Ferry, G V

    1989-06-20

    Correlative aerosol measurements taken at a limited number of altitudes during coordinated field experiments are used to test the validity of particulate extinction coefficients derived from limb path solar radiance measurements taken by the Stratospheric Aerosol and Gas Experiment (SAGE) II Sun photometer. In particular, results are presented from correlative measurement missions that were conducted during January 1985, August 1985, and July 1986. Correlative sensors included impactors, laser spectrometers, and filter samplers aboard an U-2-airplane, an upward pointing lidar aboard a P-3 airplane, and balloon-borne optical particle counters (dustsondes). The main body of this paper focuses on the July 29, 1986, validation experiment, which minimized the many difficulties (e.g., spatial and temporal inhomogeneities, imperfect coincidences) that can complicate the validation process. On this day, correlative aerosol measurements taken at an altitude of 20.5 km agreed with each other within their respective uncertainties, and particulate extinction values calculated at SAGE II wavelengths from these measurements validated corresponding SAGE II values. Additional validation efforts on days when measurement and logistical conditions were much less favorable for validation are discussed in an appendix.

  2. Atmospheric Sampling of Aerosols to Stratospheric Altitudes using High Altitude Balloons

    NASA Astrophysics Data System (ADS)

    Jerde, E. A.; Thomas, E.

    2010-12-01

    Although carbon dioxide represents a long-lived atmospheric component relevant to global climate change, it is also understood that many additional contributors influence the overall climate of Earth. Among these, short-lived components are more difficult to incorporate into models due to uncertainties in the abundances of these both spatially and temporally. Possibly the most significant of these short-lived components falls under the heading of “black carbon” (BC). There are numerous overlapping definitions of BC, but it is basically carbonaceous in nature and light absorbing. Due to its potential as a climate forcer, an understanding of the BC population in the atmosphere is critical for modeling of radiative forcing. Prior measurements of atmospheric BC generally consist of airplane- and ground-based sampling, typically below 5000 m and restricted in time and space. Given that BC has a residence time on the order of days, short-term variability is easily missed. Further, since the radiative forcing is a result of BC distributed through the entire atmospheric column, aircraft sampling is by definition incomplete. We are in the process of planning a more comprehensive sampling of the atmosphere for BC using high-altitude balloons. Balloon-borne sampling is a highly reliable means to sample air through the entire troposphere and into the lower stratosphere. Our system will incorporate a balloon and a flight train of two modules. One module will house an atmospheric sampler. This sampler will be single-stage (samples all particle sizes together), and will place particles directly on an SEM sample stub for analysis. The nozzle depositing the sample will be offset from the center of the stub, placing the aerosol particles toward the edge. At various altitudes, the stub will be rotated 45 degrees, providing 6-8 sample “cuts” of particle populations through the atmospheric column. The flights will reach approximately 27 km altitude, above which the balloons

  3. Possible climatic implications of high-altitude black carbon emissions

    NASA Astrophysics Data System (ADS)

    Govardhan, Gaurav; Krishnakumari Satheesh, Sreedharan; Nanjundiah, Ravi; Krishna Moorthy, Krishnaswamy; Babu, Surendran Suresh

    2017-08-01

    On account of its strong absorption of solar and terrestrial radiation, black carbon (BC) aerosol is known to impact large-scale systems, such as the Asian monsoon and the Himalayan glaciers, in addition to affecting the thermal structure of the lower atmosphere. While most studies focus on the near-surface abundance and impacts of BC, our study examines the implications of sharp and confined layers of high BC concentration (called elevated BC layers) at altitudes more than 4 km over the Indian region using the online regional chemistry transport model (WRF-Chem) simulations. These elevated BC layers were revealed in the recent in situ measurements using high-altitude balloons carried out on 17 March 2010, 8 January 2011 and 25 April 2011. Our study demonstrates that high-flying aircraft (with emissions from the regionally fine-tuned MACCity inventory) are the most likely cause of these elevated BC layers. Furthermore, we show that such aircraft-emitted BC can be transported to upper tropospheric or lower stratospheric heights ( ˜ 17 km) aided by the strong monsoonal convection occurring over the region, which is known to overshoot the tropical tropopause, leading to the injection of tropospheric air mass (along with its constituent aerosols) into the stratosphere. We show observational evidence for such an intrusion of tropospheric BC into the stratosphere over the Indian region using extinction coefficient and particle depolarisation ratio data from CALIOP Lidar on-board the CALIPSO satellite. We hypothesise that such intrusions of BC into the lower stratosphere and its consequent longer residence time in the stratosphere have significant implications for stratospheric ozone, especially considering the already reported ozone-depleting potential of BC.

  4. Evolution of Titan's atmospheric aerosol under high-altitude ultraviolet irradiation

    NASA Astrophysics Data System (ADS)

    Tigrine, S.; Carrasco, N.; Mahjoub, A.; Fleury, B.; Cernogora, G.; Nahon, L.; Pernot, P.; Gudipati, M.

    2015-10-01

    The Cassini-Huygens space mission revealed that the chemistry initiating Titan's aerosols formation starts in the upper layers of the atmosphere (~1000 km). The grains then sediment until deposition at the surface. Despite all the data collected, the photochemical evolution of the aerosols between 1000 and 600 km is still unknown, especially regarding their optical properties. The aim of this work is to investigate the photochemical aging processes of those aerosols and how they interact with the VUV solar radiations. We put our results in perspective with the Cassini data for different atmospheric altitudes.

  5. Design study for a gound microwave power transmission system for use with a high-altitude powered platform

    NASA Technical Reports Server (NTRS)

    Brown, W. C.

    1983-01-01

    The conceptual design of a ground-based microwave power transmission system is described. This system is intended to supply electrical power via an air link to a high-altitude (21 km) powered platform. The platform must be equipped with the required instrumentation (RECTENNA) to convert the RF energy to dc power.

  6. Tidally Induced Variations of Polar Mesospheric Cloud Altitudes and Ice Water Content using a Data Assimilation System

    DTIC Science & Technology

    2010-01-01

    based horizontal meteor winds observed at 69°N ( Andenes , Norway) and 85 km geometric altitude in Figure 5. In addition, we performed five short term...calculating winds and the Andenes data. 2.2. Ice Particle Trajectories and CARMA [22] As noted earlier, our approach is a two‐step process. We first use

  7. A Hyperspectral Thermal Emission Spectrometer (HyTES) for High Altitude Applications

    NASA Astrophysics Data System (ADS)

    Mihaly, J. M.; Johnson, W. R.; Eng, B. T.; Staniszewski, Z. K.; Hook, S. J.

    2015-12-01

    The Hyperspectral Thermal Emission Spectrometer (HyTES) is an airborne imaging spectrometer developed by JPL and originally configured on the Twin Otter aircraft. The instrument utilizes a thermal infrared Dyson imaging spectrometer and provides 256 spectral channels between 7.5 and 12 micrometers with 512 spatial pixels cross-track over a 50 degree field of view. HyTES has successfully completed multiple campaigns on the low altitude Twin Otter platform and is now capable of routinely capturing multi-species gas plumes over urban and other science-applicable environments. Current system upgrades and modifications are underway to configure HyTES on the ER-2 high altitude aircraft. The ER-2 aircraft will fly at an altitude greater than 18 km (60,000 ft) and provide a wide swath width with 35 m ground pixel size. High altitude observations from HyTES on the ER-2 platform will be used to support HyspIRI TIR measurement development. The modifications to the system maintain the capability of the HyTES instrument on the Twin Otter aircraft and a new vacuum enclosure significantly reduces both the mass and volume of the instrument scanhead. The current instrument performance, upgrades, and specifications of the high altitude system will be presented.

  8. Macroscopic time and altitude distribution of plasma turbulence induced in ionospheric modification experiments

    SciTech Connect

    Rose, H.; Dubois, D.; Russell, D.; Hanssen, A.

    1996-03-01

    This is the final report of a three-year Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). This research concentrated on the time dependence of the heater, induced-turbulence, and electron-density profiles excited in the ionosphere by a powerful radio-frequency heater wave. The macroscopic density is driven by the ponderomotive pressure and the density self-consistently determines the heater propagation. For typical parameters of the current Arecibo heater, a dramatic quasi-periodic behavior was found. For about 50 ms after turn-on of the heater wave, the turbulence is concentrated at the first standing-wave maximum of the heater near reflection altitude. From 50--100 ms the standing-wave pattern drops by about 1--2 km in altitude and the quasi-periodicity reappears at the higher altitudes with a period of roughly 50 ms. This behavior is due to the half-wavelength density depletion grating that is set up by the ponderomotive pressure at the maxima of the heater standing-wave pattern. Once the grating is established the heater can no longer propagate to higher altitudes. The grating is then unsupported by the heater at these altitudes and decays, allowing the heater to propagate again and initiate another cycle. For stronger heater powers, corresponding to the Arecibo upgrade and the HAARP heater now under construction, the effects are much more dramatic.

  9. Changes in exercise heart rate in lowlanders after prolonged stay at high altitude (4000 m).

    PubMed

    Gupta, J S; Dua, G L; Srinivasulu, N; Malhortra, M S

    1975-07-01

    Studies were conducted on cardiac frequency during submaximal and maximal work on 26 sea-level residents prior to transfer to and during stay at high altitude for 1, 10, and 20 months. Maximal O2 uptake and performance in a 1.6 km run were observed. Results indicated a significant drop in Vo2 after arrival at altitude followed by recovery with further stay. The mean maximum heart rate decreased to 182.8 beats/min after 1 month at high altitude from a seal-level mean value of 188.4 beats/min. It increased to 199.2 beats/min and decreased to 185.6 beats/min after 10 and 20 months, respectively. Heart rate, during submaximal work requiring 1.0 and 1.5 102/min, indicated the highest rate after 1 month at altitude and decreased with prolonged stay, but remained higher than the sea-level value. These changes were compared with the high-altitude native residents.

  10. On the speed of sound in the atmosphere as a function of altitude and frequency

    NASA Astrophysics Data System (ADS)

    Bass, Henry E.; Hetzer, Claus H.; Raspet, Richard

    2007-08-01

    Sutherland and Bass (2004) have developed a calculation of the speed of sound and attenuation at altitudes up to 160 km. Dispersion is included in their treatment though emphasis is placed on absorption. That theory is explored in more detail to describe dispersion in the thermosphere. In the lower atmosphere, variations in the speed of sound with altitude are dominated by temperature and wind speed changes; the vibrational and rotational relaxation frequencies, which depend on the ratio of frequency to pressure (f/P), are in the kilohertz to megahertz range. As altitude increases, f/P and the mean free path increase, relaxation frequencies drop significantly, and velocity dispersion due to rotational and translational relaxation intensifies. This relaxation and resulting dispersion cause sound speeds at fixed frequencies to increase significantly with altitude, and to lower the altitude at which sound is refracted downward. Although the most extreme effects of dispersion are masked by simultaneously increased attenuation, decreases in traveltime of several percent are predicted at frequencies slightly below 1 Hz, demonstrating that this dispersion must be taken into account in order to correctly predict atmospheric returns at low frequencies.

  11. Extremely Low Ionospheric Peak Altitudes in the Polar-Hole Region

    NASA Technical Reports Server (NTRS)

    Benson, Robert F.; Grebowsky, Joseph M.

    1999-01-01

    Vertical electron-density (N (sub e)) profiles, deduced from newly-available ISIS-II digital ionospheric topside-sounder data, are used to investigate the "polar-hole" region within the winter, nighttime polar cap ionosphere during solar minimum. The hole region is located around 0200 MLT near the poleward side of the auroral oval. Earlier investigations had revealed very low N (sub e) values in this region (down to 200/cu cm near 300 km). In the present study, such low N, values (approx. 100/cu cm) were only found near the ISIS (International Satellite for Ionospheric Study)-II altitude of 1400 km. The peak ionospheric concentration below the spacecraft remained fairly constant (approx. 10 (exp 5)/cu cm across the hole region but the altitude of the peak dropped dramatically. This peak dropped, surprisingly, to the vicinity of 100 km. These observations suggest that the earlier satellite in situ measurements, interpreted as deep holes in the ionospheric F-region concentration, could have been made during conditions of an extreme decrease in the altitude of the ionospheric N (sub e) peak. The observations, in combination with other data, indicate that the absence of an F-layer peak may be a frequent occurrence at high latitudes.

  12. Anisotropic ion heating and BBELF waves within the low-altitude ion upflow region

    NASA Astrophysics Data System (ADS)

    Shen, Y.; Knudsen, D. J.; Burchill, J. K.; James, H. G.; Miles, D. M.

    2016-12-01

    Previous studies have shown that low-energy (<10 eV) ion upflow energization processes involve multiple steps. At the initial stage, contributions from transverse-to-B ion heating by wave-particle interaction (WPI) are often underestimated. The wave-generation mechanisms, the specific wave modes leading to the ion heating, and the minimum altitude where WPI takes place remain unresolved. With this in mind, we statistically investigate the relation between anisotropic ion temperature enhancements and broadband extremely low frequency (BBELF) wave emissions within the ion upflow region using data from the Suprathermal Electron imager (SEI), the Fluxgate Magnetometer (MGF), and the Radio Receiver Instrument (RRI) onboard the e-POP satellite. Initial results demonstrate that perpendicular-to-B ion temperatures can reach up to 4.3 eV in approximately 1 km wide spatial region near 410 km altitude inside an active auroral surge. Intense small-scale field-aligned currents (FACs) as well as strong BBELF wave emissions, comprising electromagnetic waves below 80 Hz and electrostatic waves above, accompany these ion heating events. The minimum altitude of potential WPI reported here is lower than as previously suggested as 520 km by Frederick-Frost et al. 2007. We measure polarization and power spectral density for specific wave modes to explore the nature of ion heating within the BBELF waves. Acknowledgement: This research is supported by an Eyes High Doctoral Recruitment Scholarship at University of Calgary.

  13. Climate and biogeochemical sensitivity at ocean model resolutions of 100 km and 10 km

    NASA Astrophysics Data System (ADS)

    Dunne, J. P.; Galbraith, E. D.; Anderson, W.; Dufour, C. O.; Griffies, S. M.; Sarmiento, J. L.; Slater, R.; Winton, M.

    2016-02-01

    One of the representational aspirations driving current Earth System Model development is to capture the global ocean mesoscale (i.e. ocean weather) in coupled carbon-climate. The present study explores a the role of ocean model resolution (100 km and 10 km) on baseline physical and biogeochemical simulation characteristics and their response to climate change. We find the high resolution model to improve the representation of boundary currents and mesoscale phenomena, and to eliminate fictitious current structures that plague the coarse resolution models. Along with these expected improvements of smaller scales however, we also find a general lack of improvement in many of the large scale biases. With respect to sensitivity, we find the high resolution model to restrict ocean heat uptake towards the surface ocean and to exhibit somewhat less structure at the regional scale than the coarse resolution model. We find similarly more uniform patterns of carbon uptake and biogeochemicel response at high resolution consistent with a greater tendency in the high resolution model to accommodate change in the major current structures, and suggesting that some of the highly regional structure observed among CMIP5 models is due to their inability to represent the role of the mesoscale on the regional scale.

  14. Measuring Mars' Atmospheric Neutral Density from 160 to 220km with the MGS Electron Reflectometer

    NASA Astrophysics Data System (ADS)

    Lillis, R.; Engel, J.; Mitchell, D.; Brain, D.; Lin, R.; Bougher, S.; Acuna, M.

    2005-08-01

    The Magnetometer/Electron Reflectometer (MAG/ER) experiment aboard Mars Global Surveyor (MGS) samples the local electron population's distribution in energy and pitch angle (angle between electron velocity and local magnetic field direction) at the mapping orbit altitude of ˜400km. We develop a single-particle model of the electrons' interaction with the neutral atmosphere and motion along open field-lines connecting the solar wind to remnant crustal magnetization. Electron reflection from magnetic gradients and absorption due to inelastic collisons with atmospheric neutrals results in characteristic pitch angle (PA) distributions for open field lines. By assuming the validity of spherical harmonic expansions (Cain et al, 2003) in the strongest field regions of Mars (such as Terra Sirenum), we trace the electron paths and fit these PA distributions to our model to constrain the scale height and density of the neutral atmosphere in the region of greatest absorption, 160-220km. We analyse almost 3 martian years of MGS mapping Orbit Data and present the first measurements of Mars' neutral density above 180km. Although the uncertainties in single measurements are quite large, averaging over many measurements over a period of weeks allows us to see long-term trends. Major results are: 1) a mean density of 0.03 kg/km3 at 160km with a month-averaged variation of ˜40%, 2) a very strong annual seasonal variation, confirmed by periodogram and least-squares fit and 3) increasing seasonal density variability with distance from the equator. We see broad general agreement with predictions from Mars Thermosphere Global Circulation Model (MTGCM) simulations [Bougher et al, 2004] and with inferred densities from MGS Doppler tracking data [Tracadas et al, 2001]. Our results will help to constrain the upper boundaries of GCMs and assist orbital decay calculations for low-orbiting spacecraft, such as the 2005 Mars Reconnaissance Orbiter. We thank the NASA Jet Propulsion Laboratory

  15. Nitric oxide in adaptation to altitude.

    PubMed

    Beall, Cynthia M; Laskowski, Daniel; Erzurum, Serpil C

    2012-04-01

    This review summarizes published information on the levels of nitric oxide gas (NO) in the lungs and NO-derived liquid-phase molecules in the acclimatization of visitors newly arrived at altitudes of 2500 m or more and adaptation of populations whose ancestors arrived thousands of years ago. Studies of acutely exposed visitors to high altitude focus on the first 24-48 h with just a few extending to days or weeks. Among healthy visitors, NO levels in the lung, plasma, and/or red blood cells fell within 2h, but then returned toward baseline or slightly higher by 48 h and increased above baseline by 5 days. Among visitors ill with high-altitude pulmonary edema at the time of the study or in the past, NO levels were lower than those of their healthy counterparts. As for highland populations, Tibetans had NO levels in the lung, plasma, and red blood cells that were at least double and in some cases orders of magnitude greater than other populations regardless of altitude. Red blood cell-associated nitrogen oxides were more than 200 times higher. Other highland populations had generally higher levels although not to the degree shown by Tibetans. Overall, responses of those acclimatized and those presumed to be adapted are in the same direction, although the Tibetans have much larger responses. Missing are long-term data on lowlanders at altitude showing how similar they become to the Tibetan phenotype. Also missing are data on Tibetans at low altitude to see the extent to which their phenotype is a response to the immediate environment or expressed constitutively. The mechanisms causing the visitors' and the Tibetans' high levels of NO and NO-derived molecules at altitude remain unknown. Limited data suggest processes including hypoxic upregulation of NO synthase gene expression, hemoglobin-NO reactions, and genetic variation. Gains in understanding will require integrating appropriate methods and measurement techniques with indicators of adaptive function under hypoxic

  16. Nitric oxide in adaptation to altitude

    PubMed Central

    Laskowski, Daniel; Erzurum, Serpil C.

    2012-01-01

    This review summarizes published information on levels of nitric oxide gas (NO) in the lungs and NO-derived liquid phase molecules in the acclimatization of visitors newly arrived at altitudes of 2500m or more and adaptation of populations whose ancestors arrived thousands of years ago. Studies of acutely exposed visitors to high altitude focus on the first 24–48 hours with just a few extending to days or weeks. Among healthy visitors, NO levels in the lung, plasma and/or red blood cells fell within three hours, but then returned toward baseline or slightly higher by 48 hours, and increased above baseline by 5 days. Among visitors ill with high-altitude pulmonary edema at the time of the study or in the past, NO levels were lower than their healthy counterparts. As for highland populations, Tibetans had NO levels in the lung, plasma and red blood cells that were at least double and in some cases orders of magnitude greater than other populations regardless of altitude. Red blood cell associated nitrogen oxides were more than two hundred times higher. Other highland populations had generally higher levels although not to the degree showed by Tibetans. Overall, responses of those acclimatized and those presumed to be adapted are in the same direction although the Tibetans have much larger responses. Missing are long-term data on lowlanders at altitude showing how similar they become to the Tibetan phenotype. Also missing are data on Tibetans at low altitude to see the extent to which their phenotype is a response to the immediate environment or expressed constitutively. The mechanisms causing the visitors’ and the Tibetans’ high levels of NO and NO-derived molecules at altitude remain unknown. Limited data suggest processes including hypoxic upregulation of NO synthase gene expression, hemoglobin-NO reactions and genetic variation. Gains in understanding will require integrating appropriate methods and measurement techniques with indicators of adaptive function

  17. MODIS 3km Aerosol Product: Algorithm and Global Perspective

    NASA Technical Reports Server (NTRS)

    Remer, L. A.; Mattoo, S.; Levy, R. C.; Munchak, L.

    2013-01-01

    After more than a decade of producing a nominal 10 km aerosol product based on the dark target method, the MODIS aerosol team will be releasing a nominal 3 km product as part of their Collection 6 release. The new product differs from the original 10 km product only in the manner in which reflectance pixels are ingested, organized and selected by the aerosol algorithm. Overall, the 3 km product closely mirrors the 10 km product. However, the finer resolution product is able to retrieve over ocean closer to islands and coastlines, and is better able to resolve fine aerosol features such as smoke plumes over both ocean and land. In some situations, it provides retrievals over entire regions that the 10 km product barely samples. In situations traditionally difficult for the dark target algorithm, such as over bright or urban surfaces the 3 km product introduces isolated spikes of artificially high aerosol optical depth (AOD) that the 10 km algorithm avoids. Over land, globally, the 3 km product appears to be 0.01 to 0.02 higher than the 10 km product, while over ocean, the 3 km algorithm is retrieving a proportionally greater number of very low aerosol loading situations. Based on collocations with ground-based observations for only six months, expected errors associated with the 3 km land product are determined to be greater than for the 10 km product: 0.05 0.25 AOD. Over ocean, the suggestion is for expected errors to be the same as the 10 km product: 0.03 0.05 AOD. The advantage of the product is on the local scale, which will require continued evaluation not addressed here. Nevertheless, the new 3 km product is expected to provide important information complementary to existing satellite-derived products and become an important tool for the aerosol community.

  18. 14 CFR 23.1527 - Maximum operating altitude.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 1 2012-01-01 2012-01-01 false Maximum operating altitude. 23.1527 Section... Information § 23.1527 Maximum operating altitude. (a) The maximum altitude up to which operation is allowed... established. (b) A maximum operating altitude limitation of not more than 25,000 feet must be established...

  19. 14 CFR 23.1527 - Maximum operating altitude.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Maximum operating altitude. 23.1527 Section... Information § 23.1527 Maximum operating altitude. (a) The maximum altitude up to which operation is allowed... established. (b) A maximum operating altitude limitation of not more than 25,000 feet must be established...

  20. 14 CFR 23.1527 - Maximum operating altitude.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Maximum operating altitude. 23.1527 Section... Information § 23.1527 Maximum operating altitude. (a) The maximum altitude up to which operation is allowed... established. (b) A maximum operating altitude limitation of not more than 25,000 feet must be established...

  1. 14 CFR 91.119 - Minimum safe altitudes: General.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 2 2013-01-01 2013-01-01 false Minimum safe altitudes: General. 91.119... § 91.119 Minimum safe altitudes: General. Except when necessary for takeoff or landing, no person may operate an aircraft below the following altitudes: (a) Anywhere. An altitude allowing, if a power...

  2. 14 CFR 91.119 - Minimum safe altitudes: General.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 2 2014-01-01 2014-01-01 false Minimum safe altitudes: General. 91.119... § 91.119 Minimum safe altitudes: General. Except when necessary for takeoff or landing, no person may operate an aircraft below the following altitudes: (a) Anywhere. An altitude allowing, if a power...

  3. 14 CFR 91.119 - Minimum safe altitudes: General.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 2 2012-01-01 2012-01-01 false Minimum safe altitudes: General. 91.119... § 91.119 Minimum safe altitudes: General. Except when necessary for takeoff or landing, no person may operate an aircraft below the following altitudes: (a) Anywhere. An altitude allowing, if a power...

  4. 14 CFR 23.1527 - Maximum operating altitude.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 1 2014-01-01 2014-01-01 false Maximum operating altitude. 23.1527 Section... Information § 23.1527 Maximum operating altitude. (a) The maximum altitude up to which operation is allowed... established. (b) A maximum operating altitude limitation of not more than 25,000 feet must be established...

  5. 14 CFR 91.119 - Minimum safe altitudes: General.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Minimum safe altitudes: General. 91.119... § 91.119 Minimum safe altitudes: General. Except when necessary for takeoff or landing, no person may operate an aircraft below the following altitudes: (a) Anywhere. An altitude allowing, if a power...

  6. 14 CFR 91.119 - Minimum safe altitudes: General.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 2 2011-01-01 2011-01-01 false Minimum safe altitudes: General. 91.119... § 91.119 Minimum safe altitudes: General. Except when necessary for takeoff or landing, no person may operate an aircraft below the following altitudes: (a) Anywhere. An altitude allowing, if a power...

  7. 14 CFR 23.1527 - Maximum operating altitude.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Maximum operating altitude. 23.1527 Section... Information § 23.1527 Maximum operating altitude. (a) The maximum altitude up to which operation is allowed... established. (b) A maximum operating altitude limitation of not more than 25,000 feet must be established...

  8. Balloon borne in-situ detection of OH in the stratosphere from 37 to 23 km

    SciTech Connect

    Stimpfle, R.M.; Lapson, L.B., Wennberg, P.O.; Anderson, J.G. )

    1989-12-01

    The OH number density in the stratosphere has been measured over the altitude interval of 37 to 23 km at midday via balloon-borne gondola launched from Palestine, Texas on July 6, 1988. OH radicals are detected with a laser induced fluorescence instrument employing a 17 kHz repetition rate copper vapor laser pumped dye laser optically coupled to an enclosed flow, in-situ sampling chamber. OH abundances ranged from 88 {plus minus} 31 pptv (1.1 {plus minus} 0.4 {times} 10{sup 7} molec cm{sup {minus}3}) in the 36 to 35 km interval to 0.9 {plus minus} 0.8 pptv (8.7 {plus minus} 7.7 {times}10{sup 5} molec cm{sup {minus}3}) in the 24 to 23 km interval. The stated uncertainty ({plus minus} 1{sigma}) includes that from both measurement precision and accuracy. Simultaneous detection of ozone and water vapor densities was carried out with separate on-board instruments.

  9. Responses of the autonomic nervous system in altitude adapted and high altitude pulmonary oedema subjects

    NASA Astrophysics Data System (ADS)

    Mathew, Lazar; Purkayastha, S. S.; Jayashankar, A.; Radhakrishnan, U.; Sen Gupta, J.; Nayar, H. S.

    1985-06-01

    Studies were carried out to ascertain the role of sympatho-parasympathetic responses in the process of adaptation to altitude. The assessment of status of autonomic balance was carried out in a group of 20 young male subjects by recording their resting heart rate, blood pressure, oral temperature, mean skin temperature, extremity temperatures, pupillary diameter, cold pressor response, oxygen consumption, cardioacceleration during orthostasis and urinary excretion of catecholamines; in a thermoneutral laboratory. The same parameters were repeated on day 3 and at weekly intervals for a period of 3 weeks, after exposing them to 3,500 m; and also after return to sea level. At altitude, similar studies were carried out in a group of 10 acclimatized lowlanders, 10 high altitude natives and 6 patients who had recently recovered from high altitude pulmonary oedema. In another phase, similar studies were done in two groups of subjects, one representing 15 subjects who had stayed at altitude (3,500 4,000 m) without any ill effects and the other comprising of 10 subjects who had either suffered from high altitude pulmonary oedema (HAPO) or acute mountain sickness (AMS). The results revealed sympathetic overactivity on acute induction to altitude which showed gradual recovery on prolonged stay, the high altitude natives had preponderance to parasympathetic system. Sympathetic preponderance may not be an essential etiological factor for the causation of maladaptation syndromes.

  10. [Effects of high altitude on bronchial asthma].

    PubMed

    Schultze-Werninghaus, G

    2008-03-01

    Sojourns in the high mountains have been recommended to patients with asthma for many decades. It is the aim of this contribution to summarise the published studies about the effects of a stay at > 1500 m above sea level on asthmatic patients. These data from 428 adolescent and adult patients indicate an improvement of asthma symptoms and lung function during sojourns at high altitude. In many patients a reduction of the steroid therapy was achievable. Profound changes in the immune system have been demonstrated at high altitude, with a reduction of B- and T-helper cell activation. Total and mite-specific immunoglobulin E antibodies decrease significantly during longer sojourns. These changes are associated with a reduction of airway inflammation (e. g., reduction of eosinophil activation, NO exhalation and bronchial hyper-responsiveness). The fact that also patients with non-allergic asthma demonstrate a reduction of their airway inflammation at high altitude suggests that the high altitude climate has beneficial effects on asthma beyond the effects of allergen avoidance. High UV exposure and low humidity could be important additional factors, to explain the reductions in asthma severity in the high mountain climate. Larger controlled studies should be performed to prove the positive effects of the high altitude climate on asthma.

  11. Imagery intelligence from low altitudes: chosen aspects

    NASA Astrophysics Data System (ADS)

    Walczykowski, P.; Kedzierski, M.

    2017-04-01

    Remote acquisition of information about phenomena and objects from an imagery is the main objective of remote sensing. The ability to realize aims of image intelligence depends on the quality of acquired remote sensing data. The imagery intelligence can be carried out from different altitudes- from satellite level to terrestrial platforms. In this article, authors are focused on chosen aspects of imagery intelligence from low altitudes. Unfortunately the term low altitudes is not precise defined, therefore, for the purpose of this article is assumed that low altitudes, are altitudes in which operate the mini unmanned aerial vehicles (mini UAVs).The quality of imagery acquired determines the level of analysis that can be performed. The imagery quality depends on many factors, such as platforms on which the sensor is mounted, imaging sensors, height from which the data are acquired and object that is investigated. The article will also present the methods for assessing the quality of imagery in terms of detection, identification, description and technical analysis of investigated objects, as well as in terms of the accuracy of their location in the images (targeting).

  12. Can High Altitude Influence Cytokines and Sleep?

    PubMed Central

    de Aquino Lemos, Valdir; dos Santos, Ronaldo Vagner Thomatieli; Lira, Fabio Santos; Rodrigues, Bruno; Tufik, Sergio; de Mello, Marco Tulio

    2013-01-01

    The number of persons who relocate to regions of high altitude for work, pleasure, sport, or residence increases every year. It is known that the reduced supply of oxygen (O2) induced by acute or chronic increases in altitude stimulates the body to adapt to new metabolic challenges imposed by hypoxia. Sleep can suffer partial fragmentation because of the exposure to high altitudes, and these changes have been described as one of the responsible factors for the many consequences at high altitudes. We conducted a review of the literature during the period from 1987 to 2012. This work explored the relationships among inflammation, hypoxia and sleep in the period of adaptation and examined a novel mechanism that might explain the harmful effects of altitude on sleep, involving increased Interleukin-1 beta (IL-1β), Interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) production from several tissues and cells, such as leukocytes and cells from skeletal muscle and brain. PMID:23690660

  13. High altitude pulmonary edema in mountain climbers.

    PubMed

    Korzeniewski, Krzysztof; Nitsch-Osuch, Aneta; Guzek, Aneta; Juszczak, Dariusz

    2015-04-01

    Every year thousands of ski, trekking or climbing fans travel to the mountains where they stay at the altitude of more than 2500-3000m above sea level or climb mountain peaks, often exceeding 7000-8000m. High mountain climbers are at a serious risk from the effects of adverse environmental conditions prevailing at higher elevations. They may experience health problems resulting from hypotension, hypoxia or exposure to low temperatures; the severity of those conditions is largely dependent on elevation, time of exposure as well as the rate of ascent and descent. A disease which poses a direct threat to the lives of mountain climbers is high altitude pulmonary edema (HAPE). It is a non-cardiogenic pulmonary edema which typically occurs in rapidly climbing unacclimatized lowlanders usually within 2-4 days of ascent above 2500-3000m. It is the most common cause of death resulting from the exposure to high altitude. The risk of HAPE rises with increased altitude and faster ascent. HAPE incidence ranges from an estimated 0.01% to 15.5%. Climbers with a previous history of HAPE, who ascent rapidly above 4500m have a 60% chance of illness recurrence. The aim of this article was to present the relevant details concerning epidemiology, pathophysiology, clinical symptoms, prevention, and treatment of high altitude pulmonary edema among climbers in the mountain environment. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. Wind study for high altitude platform design

    NASA Technical Reports Server (NTRS)

    Strganac, T. W.

    1979-01-01

    An analysis of upper air winds was performed to define the wind environment at potential operating altitudes for high altitude powered platform concepts. Wind conditions of the continental United States, Pacific area (Alaska to Sea of Japan), and European area (Norwegian and Mediterranean Sea) were obtained using a representative network of sites selected based upon adequate high altitude sampling, geographic dispersion, and observed upper wind patterns. A data base of twenty plus years of rawinsonde gathered wind information was used in the analysis. Annual variations from surface to 10 mb pressure altitude were investigated to encompass the practical operating range for the platform concepts. Parametric analysis for the United States and foreign areas was performed to provide a basis for vehicle system design tradeoffs. This analysis of wind magnitudes indicates the feasibility of annual operation at a majority of sites and more selective seasonal operation for the extreme conditions between the pressure altitudes of 100 to 25 mb based upon the assumed design speeds.

  15. MESSENGER's low-altitude plasma observations in Mercury's northern magnetospheric cusp

    NASA Astrophysics Data System (ADS)

    Raines, J. M.; Tracy, P.; Gershman, D. J.; Poh, G. K.; Slavin, J. A.; Zurbuchen, T.; Korth, H.; Anderson, B. J.; Solomon, S. C.

    2014-12-01

    In its final year in orbit, the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft is conducting a low-altitude campaign that features several periods during which the periapsis altitude will be as low as 15-25 km. During many of the low-altitude orbits, the spacecraft passes through Mercury's northern magnetospheric cusp, which has been shown by MESSENGER observations at higher altitude (200-500 km) to be a key region of coupling among the solar wind, the exosphere, and the surface regolith. Plasma and magnetic field observations at low altitudes should add substantially to an understanding of processes observed to date in this important region: (1) Protons have been observed flowing into the cusp and forming a persistent loss cone. Documentation of similar characteristics close to the surface would greatly strengthen predictions that these ions are precipitating onto Mercury's surface. (2) Upwelling low-energy (100-300 eV) Na+-group ions (mass per charge 21-30) within the cusp appear to be locally energized from surface-sputtered ions or photo-ionized exospheric neutrals. Observing the energies of these ions over a larger range of altitudes may allow the functional dependence to be determined, which would reveal further clues concerning their acceleration mechanism. (3) High-energy (>1 keV) Na+-group ions have been shown to be the dominant planetary ion in the cusp, exceeding at times the abundance of even solar wind alpha particles (He2+). In contrast to their low-energy counterparts, these ions appear to have been swept into the cusp from the dayside magnetosphere on newly reconnected field lines. The low-altitude extent of these observations, especially when compared with that of protons, can be used to evaluate this hypothesis and others concerning the entry of these high-energy ions into the cusp. (4) Short-duration, deep depressions in the magnetic field magnitude, called cusp filaments, have been commonly observed within

  16. Pulmonary Embolism Masquerading as High Altitude Pulmonary Edema at High Altitude

    PubMed Central

    Lohani, Benu; Murphy, Holly

    2016-01-01

    Abstract Pandey, Prativa, Benu Lohani, and Holly Murphy. Pulmonary embolism masquerading as high altitude pulmonary edema at high altitude. High Alt Med Biol. 17:353–358, 2016.—Pulmonary embolism (PE) at high altitude is a rare entity that can masquerade as or occur in conjunction with high altitude pulmonary edema (HAPE) and can complicate the diagnosis and management. When HAPE cases do not improve rapidly with descent, other diagnoses, including PE, ought to be considered. From 2013 to 2015, we identified eight cases of PE among 303 patients with initial diagnosis of HAPE. Upon further evaluation, five had deep vein thrombosis (DVT). One woman had a contraceptive ring and seven patients had no known thrombotic risks. PE can coexist with or mimic HAPE and should be considered in patients presenting with shortness of breath from high altitude regardless of thrombotic risk. PMID:27768392

  17. Pulmonary Embolism Masquerading as High Altitude Pulmonary Edema at High Altitude.

    PubMed

    Pandey, Prativa; Lohani, Benu; Murphy, Holly

    2016-12-01

    Pandey, Prativa, Benu Lohani, and Holly Murphy. Pulmonary embolism masquerading as high altitude pulmonary edema at high altitude. High Alt Med Biol. 17:353-358, 2016.-Pulmonary embolism (PE) at high altitude is a rare entity that can masquerade as or occur in conjunction with high altitude pulmonary edema (HAPE) and can complicate the diagnosis and management. When HAPE cases do not improve rapidly with descent, other diagnoses, including PE, ought to be considered. From 2013 to 2015, we identified eight cases of PE among 303 patients with initial diagnosis of HAPE. Upon further evaluation, five had deep vein thrombosis (DVT). One woman had a contraceptive ring and seven patients had no known thrombotic risks. PE can coexist with or mimic HAPE and should be considered in patients presenting with shortness of breath from high altitude regardless of thrombotic risk.

  18. HIGH-ALTITUDE CHAMPIONS: BIRDS THAT LIVE AND MIGRATE AT ALTITUDE.

    PubMed

    Lague, Sabine Lina

    2017-08-24

    High altitude is physiologically challenging for vertebrate life for many reasons, including hypoxia (low environmental oxygen); yet, many birds thrive at altitude. Compared to mammals, birds have additional enhancements to their oxygen transport cascade, the conceptual series of steps responsible for acquiring oxygen from the environment and transporting it to the mitochondria. These adaptations have allowed them to inhabit a number of high-altitude regions. Waterfowl are a taxon prolific at altitude. This mini-review explores the physiological responses of high-altitude waterfowl (geese and ducks), comparing the strategies of lifelong high-altitude residents to those of transient high-altitude performers, providing insight into how birds champion high-altitude life. In particular, this review highlights and contrasts the physiological hypoxia responses of bar-headed geese (Anser indicus), birds that migrate biannually through the Himalayas (4,500-6,500 m), and Andean geese (Chloephaga melanoptera), lifelong residents of the Andes (4,000-5,500m). These two species exhibit markedly different ventilatory and cardiovascular strategies for coping with hypoxia: bar-headed geese robustly increase convective oxygen transport elements (i.e. heart rate and total ventilation) whereas Andean geese rely predominantly on enhancements that are likely morphological in origin (i.e. increases in lung oxygen diffusion and cardiac stroke volume). The mini-review compares the short- and long-term cardiovascular and ventilatory trade-offs of these different physiological strategies and offers hypotheses surrounding their origins. It also draws parallels to high-altitude human physiology and research, and identifies a number of areas of further research. The field of high-altitude avian physiology offers a unique and broadly applicable insight into physiological enhancements in hypoxia. Copyright © 2017, Journal of Applied Physiology.

  19. Images of Bottomside Irregularities Observed at Topside Altitudes

    NASA Technical Reports Server (NTRS)

    Burke, William J.; Gentile, Louise C.; Shomo, Shannon R.; Roddy, Patrick A.; Pfaff, Robert F.

    2012-01-01

    We analyzed plasma and field measurements acquired by the Communication/ Navigation Outage Forecasting System (C/NOFS) satellite during an eight-hour period on 13-14 January 2010 when strong to moderate 250 MHz scintillation activity was observed at nearby Scintillation Network Decision Aid (SCINDA) ground stations. C/NOFS consistently detected relatively small-scale density and electric field irregularities embedded within large-scale (approx 100 km) structures at topside altitudes. Significant spectral power measured at the Fresnel (approx 1 km) scale size suggests that C/NOFS was magnetically conjugate to bottomside irregularities similar to those directly responsible for the observed scintillations. Simultaneous ion drift and plasma density measurements indicate three distinct types of large-scale irregularities: (1) upward moving depletions, (2) downward moving depletions, and (3) upward moving density enhancements. The first type has the characteristics of equatorial plasma bubbles; the second and third do not. The data suggest that both downward moving depletions and upward moving density enhancements and the embedded small-scale irregularities may be regarded as Alfvenic images of bottomside irregularities. This interpretation is consistent with predictions of previously reported theoretical modeling and with satellite observations of upward-directed Poynting flux in the low-latitude ionosphere.

  20. Images of Bottomside Irregularities Observed at Topside Altitudes

    NASA Astrophysics Data System (ADS)

    Gentile, L. C.; Burke, W. J.; Shomo, S. R.; Roddy, P. A.; Pfaff, R. F.

    2011-12-01

    We have analyzed plasma and field measurements acquired by the Communication/ Navigation Outage Forecasting System (C/NOFS) satellite during an eight-hour interval on 13 - 14 January 2010 when strong to moderate 250 MHz scintillation activity was observed at nearby Scintillation Network Decision Aid (SCINDA) ground stations. C/NOFS consistently detected relatively small-scale density and electric field irregularities embedded within large-scale (~100 km) structures at topside altitudes. Significant spectral power measured at the Fresnel (~1 km) scale size suggests that C/NOFS was magnetically conjugate to bottomside irregularities similar to those directly responsible for the observed scintillations. Simultaneous ion drift and plasma density measurements indicate three distinct types of large-scale irregularities: (1) upward moving depletions, (2) downward moving depletions, and (3) upward moving density enhancements. The first type has the characteristics of equatorial plasma bubbles, the second and third do not. The data suggest that both they and embedded small-scale irregularities may be regarded as Alfvénic images of bottomside irregularities. This interpretation is consistent with predictions of previously reported theoretical modeling and with satellite observations of upward directed Poynting flux in the low-latitude ionosphere.

  1. Images of bottomside irregularities observed at topside altitudes

    NASA Astrophysics Data System (ADS)

    Burke, William J.; Gentile, Louise C.; Shomo, Shannon R.; Roddy, Patrick A.; Pfaff, Robert F.

    2012-03-01

    We analyzed plasma and field measurements acquired by the Communication/Navigation Outage Forecasting System (C/NOFS) satellite during an eight-hour period on 13-14 January 2010 when strong to moderate 250 MHz scintillation activity was observed at nearby Scintillation Network Decision Aid (SCINDA) ground stations. C/NOFS consistently detected relatively small-scale density and electric field irregularities embedded within large-scale (˜100 km) structures at topside altitudes. Significant spectral power measured at the Fresnel (˜1 km) scale size suggests that C/NOFS was magnetically conjugate to bottomside irregularities similar to those directly responsible for the observed scintillations. Simultaneous ion drift and plasma density measurements indicate three distinct types of large-scale irregularities: (1) upward moving depletions, (2) downward moving depletions, and (3) upward moving density enhancements. The first type has the characteristics of equatorial plasma bubbles; the second and third do not. The data suggest that both downward moving depletions and upward moving density enhancements and the embedded small-scale irregularities may be regarded as Alfvénic images of bottomside irregularities. This interpretation is consistent with predictions of previously reported theoretical modeling and with satellite observations of upward-directed Poynting flux in the low-latitude ionosphere.

  2. Low-Altitude Magnetic Topology with MAVEN SWEA and MAG

    NASA Astrophysics Data System (ADS)

    Mitchell, David; Xu, Shaosui; Mazelle, Christian; Luhmann, Janet; McFadden, James; Connerney, John; Liemohn, Michael; Dong, Chuanfei; Bougher, Stephen; Fillingim, Matthew

    2016-04-01

    The Solar Wind Electron Analyzer (SWEA) and Magnetometer (MAG) onboard the MAVEN spacecraft measure electron pitch angle and energy distributions at 2-second resolution (~8 km along the orbit track) to determine the topology of magnetic fields from both external and crustal sources. Electrons from different regions of the Mars environment can be distinguished by their energy distributions. Thus, pitch angle resolved energy spectra can be used to determine the plasma source regions sampled by a field line at large distances from the spacecraft. From 12/1/2014 to 2/15/2015, when periapsis was at high northern latitudes, SWEA observed ionospheric photoelectrons at low altitudes (140-200 km) and high solar zenith angles (120-145 degrees) on ~35% of the orbits. Since this electron population is unambiguously produced in the dayside ionosphere, these observations demonstrate that the deep Martian nightside is at times magnetically connected to the sunlit hemisphere. The BATS-R-US Mars multi-fluid MHD model suggests the presence of closed crustal magnetic field lines over the northern hemisphere that straddle the terminator and extend to high SZA. Simulations with the SuperThermal Electron Transport (STET) model show that photoelectron transport along such field lines can take place without significant attenuation. Precipitation of photoelectrons onto the night-side atmosphere should cause ionization and possibly auroral emissions in localized regions. On one orbit, the O2+ energy flux measured by STATIC correlates well with precipitating photoelectron fluxes.

  3. Sonic Thermometer for High-Altitude Balloons

    NASA Technical Reports Server (NTRS)

    Bognar, John

    2012-01-01

    The sonic thermometer is a specialized application of well-known sonic anemometer technology. Adaptations have been made to the circuit, including the addition of supporting sensors, which enable its use in the high-altitude environment and in non-air gas mixtures. There is a need to measure gas temperatures inside and outside of superpressure balloons that are flown at high altitudes. These measurements will allow the performance of the balloon to be modeled more accurately, leading to better flight performance. Small thermistors (solid-state temperature sensors) have been used for this general purpose, and for temperature measurements on radiosondes. A disadvantage to thermistors and other physical (as distinct from sonic) temperature sensors is that they are subject to solar heating errors when they are exposed to the Sun, and this leads to issues with their use in a very high-altitude environment

  4. Paschen Considerations for High Altitude Airships

    NASA Technical Reports Server (NTRS)

    Ferguson, D. C.; Hillard, G. B.

    2004-01-01

    Recently, there have been several proposals submitted to funding agencies for long-lived high altitude (about 70,000 feet) airships for communications, surveillance, etc. In order for these airships to remain at altitude, high power, high efficiency, lightweight solar arrays must be used, and high efficiency power management and distribution systems must be employed. The needs for high power and high efficiency imply high voltage systems. However, the air pressure at these extreme altitudes is such that electrical power systems will be near the Paschen discharge minimum over a wide range of electrode separations. In this paper, preliminary calculations are made for acceptable high voltage design practices under ambient, hydrogen and helium gas atmospheres.

  5. Tests of artificial flight at high altitudes

    NASA Technical Reports Server (NTRS)

    Gradenwitz, Arthur

    1920-01-01

    If we wish to form an accurate idea of the extraordinary progress achieved in aeronautics, a comparison must be made of the latest altitude records and the figures regarded as highest attainable limit some ten years ago. It is desirable, for two reasons, that we should be able to define the limit of the altitudes that can be reached without artificial aid. First, to know to what extent the human body can endure the inhalation of rarified air. Second, the mental capacity of the aviator must be tested at high altitudes and the limit known below which he is able to make reliable observations without being artificially supplied with oxygen. A pneumatic chamber was used for the most accurate observations.

  6. Determination of the altitude of the nitric acid layer from very high resolution ground-based IR solar spectra

    NASA Technical Reports Server (NTRS)

    Blatherwick, R. D.; Murcray, F. J.; Murcray, D. G.; Locker, M. H.

    1991-01-01

    A ground-based solar spectrum at a spectral resolution of about 0.002/cm is used to determine the altitude of the HNO3 layer. The 870/cm spectral region, which is essentially free from absorptions from other species, is employed. The data were obtained with the University of Denver 2.5-m maximum path difference Fourier Transform interferometer spectrometer system. A set of 13 HNO3 vertical profiles were used in the analysis. The best fit obtained for the 'starting' profile (which is centered at 24 km), and the best fit for the profile centered at 26 km are shown. For displacements of greater than 2 km, the discrepancy between the synthetic and observed spectra becomes readily discernible by inspection of the spectra. It is shown that the 'best fit' rms residuals are quite sensitive to the assumed altitude of the HNO3 layer.

  7. Low altitude cloud height and methane humidity retrievals on Titan in the near-IR

    NASA Astrophysics Data System (ADS)

    Adamkovics, M.; Hayes, A.; Mitchell, J.; De Pater, I.; Young, E.

    2013-12-01

    The formation of low altitude clouds on Titan, with cloud-top altitudes below ~10km, likely occurs by a fundamentally different mechanism than for the clouds commonly observed to have cloud-tops in the upper troposphere, above ~15km [1]. Near-infrared spectroscopy of clouds has been the method of choice for determining cloud altitudes [2], however, uncertainties in aerosols scattering properties and opacities, together with limitations in laboratory measurements of gas opacities (in particular for methane), lead to uncertainties in how accurately the altitude of low clouds can be retrieved [3]. Here we revisit near-IR spectra obtained with Keck and Cassini using new laboratory methane line data in the HITRAN 2012 database [4] to address the problem of measuring the altitudes of low clouds. We discuss the role of topography in relation to the formation of low clouds and other diagnostics of conditions near the surface, such as the tropospheric methane humidity. We reanalyze measurements the tropospheric humidity variation [5] and describe observational strategies for improved diagnostics of the tropospheric humidity on Titan . Acknowledgements: Funding for this work is provided by the NSF grant AST-1008788 and NASA OPR grant NNX12AM81G. References: [1] Brown, et al. (2009) ApJ, 706, L110-L113. [2] Ádámkovics et al. (2010) Icarus, 208, 868-877. [3] Griffith et al. (2012) Icarus, 218, 975-988. [4] Rothman et al. (2013) AIP Conf. Proc., 1545, 223-231. [5] Penteado & Griffith (2010) Icarus, 206, 345-351.

  8. Quiet-time plasma irregularities at 1400 km in the cleft region

    NASA Technical Reports Server (NTRS)

    Kayser, S. E.; Maier, E. J.; Brace, L. H.

    1978-01-01

    The quiet north polar cleft at 1400 km was studied by Isis-2 instruments, and data from the retarding potential analyzer and the cylindrical electrostatic probe show that thermal plasma density fluctuations are distributed in a region between 75 deg and 82 deg invariant latitude and approximately dawn to dusk. Cleft shape and shape variations are described. Thermal ions and thermal electrons usually fluctuated together, but suprathermal electrons fluctuated independently. Data on thermal plasma patterns correlates fairly well with observations of soft particles and auroral optical emissions and not as well with measurements of high-energy particles. The data suggest that the energy source for the thermal irregularities is associated with soft particles and that precipitating high-energy particles do not drive the thermal plasma at these altitudes.

  9. Study on the performance of electromagnetic particle detectors of LHAASO-KM2A

    NASA Astrophysics Data System (ADS)

    Zhang, Zhongquan; Hou, Chao; Cao, Zhen; Chang, Jingfan; Feng, Cunfeng; Hanapia, Erlan; Gong, Guanghua; Liu, Jia; Lv, Hongkui; Sheng, Xiangdong; Zhang, Shaoru; Zhu, Chengguang

    2017-02-01

    The electromagnetic particle detectors (EDs) for one square kilometer detector array (KM2A) of large high altitude air shower observation (LHAASO) are designed to measure the densities and arrival times of secondary particles in extensive air showers (EASs). ED is a type of plastic scintillator detector with an active area of 1 m2. This study investigates the design and performance of prototype ED. Approximately 20 photoelectrons are collected by the 1st dynode of a photomultiplier tube (PMT). The prototype ED exhibited good detection efficiency and time resolution. The detection for the wide dynamic particle density varying from 1 to 10 000 particles/m2 is realized with the design of the PMT divider for the readout of both the anode and 6th dynode.

  10. Quiet-time plasma irregularities at 1400 km in the cleft region

    NASA Technical Reports Server (NTRS)

    Kayser, S. E.; Maier, E. J.; Brace, L. H.

    1978-01-01

    The quiet north polar cleft at 1400 km was studied by Isis-2 instruments, and data from the retarding potential analyzer and the cylindrical electrostatic probe show that thermal plasma density fluctuations are distributed in a region between 75 deg and 82 deg invariant latitude and approximately dawn to dusk. Cleft shape and shape variations are described. Thermal ions and thermal electrons usually fluctuated together, but suprathermal electrons fluctuated independently. Data on thermal plasma patterns correlates fairly well with observations of soft particles and auroral optical emissions and not as well with measurements of high-energy particles. The data suggest that the energy source for the thermal irregularities is associated with soft particles and that precipitating high-energy particles do not drive the thermal plasma at these altitudes.

  11. Shuttle high resolution accelerometer package experiment results - Atmospheric density measurements between 60-160 km

    NASA Technical Reports Server (NTRS)

    Blanchard, R. C.; Hinson, E. W.; Nicholson, J. Y.

    1988-01-01

    Indirect or inferred values of atmospheric density encountered by the Shuttle Orbiter during reentry have been calculated from acceleration measurements made by the High Resolution Accelerometer Package (HiRAP) and the Orbiter Inertial Measurement Unit (IMU) liner accelerometers. The atmospheric density data developed from this study represent a significant gain with respect to the body of data collected to date by various techniques in the altitude range of 60 to 160 km. The data are unique in that they cover a very wide horizontal range during each flight and provide insight into the actual density variations encountered along the reentry flight path. The data, which were collected over about 3 years, are also characterized by variations in solar activity, geomagnetic index, and local solar time. Comparison of the flight-derived densities with various atmospheric models have been made, and analyses have attempted to characterize the data and to show correlation with selected physical variables.

  12. Pioneer Venus 12.5 km Anomaly Workshop Report, volume 1

    NASA Technical Reports Server (NTRS)

    Seiff, A.; Sromovsky, L.; Borucki, W.; Craig, R.; Juergens, D.; Young, R. E.; Ragent, B.

    1995-01-01

    A workshop was convened at Ames Research Center on September 28 and 29, 1993, to address the unexplained electrical anomalies experienced in December 1978 by the four Pioneer Venus probes below a Venus altitude of 12.5 km. These anomalies caused the loss of valuable data in the deep atmosphere, and, if their cause were to remain unexplained, could reoccur on future Venus missions. The workshop participants reviewed the evidence and studied all identified mechanisms that could consistently account for all observed anomalies. Both hardware problems and atmospheric interactions were considered. Based on a workshop recommendation, subsequent testing identified the cause as being an insulation failure of the external harness. All anomalous events are now explained.

  13. Status Update Report for the Peregrine 100km Sounding Rocket Project

    NASA Technical Reports Server (NTRS)

    Dyer, Jonny; Zilliac, Greg; Doran, Eric; Marzona, Mark Thadeus; Lohner, Kevin; Karlik, Evan; Cantwell, Brian; Karabeyoglu, Arif

    2008-01-01

    The Peregrine Sounding Rocket Program is a joint basic research program of NASA Ames Research Center, NASA Wallops, Stanford University and the Space Propulsion Group, Inc. (SPG). The goal is to determine the applicability of liquifying hybrid technology to a small launch system. The approach is to design, build, test and y a stable, efficient liquefying fuel hybrid rocket vehicle to an altitude of 100 km. The program was kicked o in October of 2006 and has seen considerable progress in the subsequent 18 months. Two virtually identical vehicles will be constructed and own out of the NASA Sounding Rocket Facility at Wallops Island. This paper presents the current status of the project as of June 2008. For background on the project, the reader is referred to last year's paper.

  14. Results of 150-km, 1-Gbps lasercom validation experiment using aircraft motion simulator

    NASA Astrophysics Data System (ADS)

    Chan, Victor J.; Bloom, Scott H.

    1996-04-01

    Laser communications between high flying aircraft such as high altitude unmanned aerial vehicles and between the aircraft and the ground (weather permitting) offers the potential to transfer extremely high amounts of information faster and with a smaller package than is currently possible with a radio frequency and microwave technologies. Over the last few years, BMDO has funded a number of technology efforts through the U.S. Army Space and Strategic Defense Command reducing the risks associated with laser communications. One of these efforts, at ThermoTrex Corporation in San Diego, California, is now being carried forward towards an advanced technology demonstration. The program will lead to the demonstration of high data rate communications of 274 Mbit/s to 1.2 Gbit/s between high altitude aircraft and between a satellite and the ground. To identify and further reduce the risks associated with operating the lasercom system on a high flying aircraft, a demonstration of a long range link in the presence of simulated aircraft motion was performed. Link acquisition utilizes an interface to an inertial navigation unit for initial pointing and atomic line filter technology for background light rejection. In addition, data was taken on the effects of atmospheric turbulence on the intensity of received laser light across the 150 km path. We present the development of the tracking system and results of the experiment performed at Mauna Loa, Hawaii and Haleakala, Maui in May and September 1995.

  15. High-altitude plume computer code development

    NASA Technical Reports Server (NTRS)

    Audeh, B. J.; Murphy, J. E.

    1985-01-01

    The flowfield codes that have been developed to predict rocket motor plumes at high altitude were used to predict plume properties for the RCS motor which show reasonable agreement with experimental data. A systematic technique was established for the calculation of high altitude plumes. The communication of data between the computer codes was standardized. It is recommended that these outlined procedures be more completed, documented and updated as the plume methodology is applied to the varied problems of plume flow and plume impingement encountered by space station design and operation.

  16. Progress on low altitude cloud icing research

    NASA Technical Reports Server (NTRS)

    Jeck, R. K.

    1981-01-01

    The icing environment at altitudes below 10,000 feet were studied. The following questions are asked, are: (1) existing aircraft certification criteria applicable; (2) too stringent on icing for helos; (3) based on accurate data; (4) appropriate for low (10,000 ft) altitudes? The research plan is outlined: review historical icing data, obtain new measurements, collect modern icing data from other groups, and recommend LWC, OAT, and MVD criteria for helicopters. Estimated accuracies and known sources of error are included. It is concluded that the net effect of possible sources of error of both signs is uncertain.

  17. Progress on low altitude cloud icing research

    NASA Technical Reports Server (NTRS)

    Jeck, R. K.

    1981-01-01

    The icing environment at altitudes below 10,000 feet were studied. The following questions are asked, are: (1) existing aircraft certification criteria applicable; (2) too stringent on icing for helos; (3) based on accurate data; (4) appropriate for low (10,000 ft) altitudes? The research plan is outlined: review historical icing data, obtain new measurements, collect modern icing data from other groups, and recommend LWC, OAT, and MVD criteria for helicopters. Estimated accuracies and known sources of error are included. It is concluded that the net effect of possible sources of error of both signs is uncertain.

  18. Atmospheric radioactive isotopes at orbital altitudes.

    PubMed

    Gregory, J C

    1996-11-01

    The radioactive isotope 7Be was discovered on the forward-facing side of the LDEF satellite in amounts far exceeding that expected from direct cosmic ray activation of the spacecraft material. This prompted an examination of the production of cosmogenic isotopes in the atmosphere and of the processes by which they may be transported to orbital altitudes and adsorbed by a spacecraft. 7Be is only one of several atmospheric cosmogenic isotopes that might be detectable at orbital altitudes and that might prove to be as useful as tracers of atmospheric circulation processes in the mesosphere and thermosphere as they have been in the lower layers of the atmosphere.

  19. Atmospheric electron flux at airplane altitude

    SciTech Connect

    Enomoto, R.; Chiba, J.; Ogawa, K.; Sumiyoshi, T.; Takasaki, F. ); Kifune, T. ); Matsubara, Y. ); Nishimura, J. )

    1991-12-01

    We have developed a new detector to systematically measure the cosmic-ray electron flux at airplane altitudes. We loaded a lead-glass-based electron telescope onto a commercial cargo airplane. The first experiment was carried out using the air route between Narita (Japan) and Sydney (Australia); during this flight we measured the electron flux at various altitudes and latitudes. The thresholds of the electron energies were 1, 2, and 4 GeV. The results agree with a simple estimation using one-dimensional shower theory. A comparison with a Monte Carlo calculation was made.

  20. Optimal Shuttle Altitude Changes Using Tethers.

    DTIC Science & Technology

    1986-12-01

    05 UNCLRESIF lED F/6 22/ ML EhEL hom hhhomhhIl mhEohmhhhhEmhE . 1.25 A11 11. 6 DIX, FILE COpv 0,, I ~OF OPTIMAL SHUTTLE ALTITUDE CHANGES USING TETHERS...satellites in the Earth’s upper atmosphere for research into upper atmospheric physics. An extremely simple disposable tether "toes" system is under...choosing these coefficients. I 24 S 13L Do v hmsm of the00 Rilnsto outin. The purpose of this research is to develop a method for Ing the altitude

  1. Development of a Radio Acoustic Sounding System (RASS) for continuous temperature profiling upto lower stratospheric altitudes

    NASA Astrophysics Data System (ADS)

    Chandrasekhar Sarma, T. V.; Tsuda, Toshitaka

    2012-07-01

    The Gadanki (13.46°N, 79.17°E) MST radar is a high power VHF pulsed coherent Doppler radar established for remote probing of atmospheric phenomena in the Mesosphere Stratosphere Troposphere regions. Radio Acoustic Sounding System (RASS) was developed using this radar to obtain height profiles of atmospheric temperature up to lower stratospheric altitudes. RASS uses the effect of temperature on the speed of sound in air as a means to sense the atmospheric temperature. It is the combination of a Doppler radar and acoustic exciters. The radar was augmented with acoustic exciters that were designed and constructed for this purpose. The Doppler radar profiles the speed of refractive index perturbations induced by the acoustic source. RASS has been demonstrated to be a reliable ground-based remote profiling technique to obtain altitude profiles of atmospheric virtual temperature, Tv over the past two decades. This work describes the design of the system and its application to the observation of height profiles of atmospheric virtual temperature up to and beyond tropical tropopause altitudes. Observations were made during 2007, 2008 and 2009 over periods extending up to 72 hours. These observations demonstrate temperature profiling capability up to about 18 km in altitude, though on an occasion height coverage upto 22.8km was obtained briefly; lowest height covered is from about 1.5km onwards. During the period of the RASS observations simultaneous data from radiosonde was used to validate the temperature measurements. Simultaneous satellite-based measurement of outgoing long wave radiation (OLR) and precipitation from ground-based instruments was used to study the atmospheric phenomena of gravity waves and atmospheric stability during a convection event.

  2. A warm layer in Venus' cryosphere and high-altitude measurements of HF, HCl, H2O and HDO.

    PubMed

    Bertaux, Jean-Loup; Vandaele, Ann-Carine; Korablev, Oleg; Villard, E; Fedorova, A; Fussen, D; Quémerais, E; Belyaev, D; Mahieux, A; Montmessin, F; Muller, C; Neefs, E; Nevejans, D; Wilquet, V; Dubois, J P; Hauchecorne, A; Stepanov, A; Vinogradov, I; Rodin, A; Bertaux, Jean-Loup; Nevejans, D; Korablev, Oleg; Montmessin, F; Vandaele, Ann-Carine; Fedorova, A; Cabane, M; Chassefière, E; Chaufray, J Y; Dimarellis, E; Dubois, J P; Hauchecorne, A; Leblanc, F; Lefèvre, F; Rannou, P; Quémerais, E; Villard, E; Fussen, D; Muller, C; Neefs, E; Van Ransbeeck, E; Wilquet, V; Rodin, A; Stepanov, A; Vinogradov, I; Zasova, L; Forget, F; Lebonnois, S; Titov, D; Rafkin, S; Durry, G; Gérard, J C; Sandel, B

    2007-11-29

    Venus has thick clouds of H2SO4 aerosol particles extending from altitudes of 40 to 60 km. The 60-100 km region (the mesosphere) is a transition region between the 4 day retrograde superrotation at the top of the thick clouds and the solar-antisolar circulation in the thermosphere (above 100 km), which has upwelling over the subsolar point and transport to the nightside. The mesosphere has a light haze of variable optical thickness, with CO, SO2, HCl, HF, H2O and HDO as the most important minor gaseous constituents, but the vertical distribution of the haze and molecules is poorly known because previous descent probes began their measurements at or below 60 km. Here we report the detection of an extensive layer of warm air at altitudes 90-120 km on the night side that we interpret as the result of adiabatic heating during air subsidence. Such a strong temperature inversion was not expected, because the night side of Venus was otherwise so cold that it was named the 'cryosphere' above 100 km. We also measured the mesospheric distributions of HF, HCl, H2O and HDO. HCl is less abundant than reported 40 years ago. HDO/H2O is enhanced by a factor of approximately 2.5 with respect to the lower atmosphere, and there is a general depletion of H2O around 80-90 km for which we have no explanation.

  3. Variability in low altitude astronomical refraction as a function of altitude.

    PubMed

    Sampson, Russell D; Lozowski, Edward P; Fathi-Nejad, Arsha

    2008-12-01

    Low altitude astronomical refraction (LAAR) of the setting Sun was measured over a sea horizon from a coastal location in Barbados, West Indies. The altitude of the upper limb of the Sun and the apparent horizon were determined using a digital video camera (Canon XL2) and a digital SLR camera (Canon EOS 5D). A total of 14 sunsets were measured between 2005 and 2007. From these measurements LAAR variability was estimated at 14 standard altitudes of the refracted Sun between 0 degrees .01 and 4 degrees .5. The relative variability decreases with increasing altitude from +/- 0.0195 of mean refraction at an altitude of 0 degrees .01 to +/- 0.0142 at 4 degrees .5. If extrapolated to an altitude of 15 degrees , a linear fit to the data produces a relative variability of +/- 0.0038 and an absolute variability of +/- 0(").45. Statistical analysis of the relative variability in LAAR appears to support the decreasing trend. However, error propagation analysis further suggests that the observed values of refraction may exceed the accuracy of the measurement system at altitudes higher than 2 degrees .

  4. Coherent scatter radar observations of 150-km echoes and vertical plasma drifts in the Brazilian sector

    NASA Astrophysics Data System (ADS)

    Rodrigues, F. S.; de Paula, E. R.; Hysell, D. L.; Chau, J. L.

    2008-12-01

    Coherent scatter echoes coming from the valley region (~150 km altitude) in the equatorial ionosphere during daytime have been detected by the Jicamarca radar in Peru for several decades (Basley, 1945). More recently, it was found that the vertical Doppler shift of these echoes corresponds to the vertical velocity of the F-region background plasma (Kudeki and Fawcett, 1993; Woodman and Villanueva,1995, Chau and Woodman, 2004). Jicamarca now uses observations of 150-km echoes to provide estimates of the diurnal variation of the equatorial vertical plasma drifts in addition to traditional incoherent scatter radar drift measurements. These 150-km echoes have also been observed in other longitude sectors (e.g. Tsunoda and Ecklund,2004; Patra et al., 2008). Additionally, these echoes have also been detected in a semi-routine basis with a small, low-power radar in Sao Luis, Brazil. Initial results of our analysis suggest that vertical plasma drifts can be estimated from these observations. These measurements combined with simultaneous measurements made by the Jicamarca radar and the C/NOFS satellite can help us better understand the day-to-day variability and longitudinal variation of equatorial electric fields. In this talk we will present examples of 150-km echoes observations made with the Sao Luis radar. We will describe how vertical drifts can be estimated from the observations and how the vertical drifts over Sao Luis compare with the drifts measured simultaneously at Jicamarca. These new measurements can provide important new information about the low-latitude electrodynamics, and consequently to the C/NOFS mission.

  5. Reducing body fat with altitude hypoxia training in swimmers: role of blood perfusion to skeletal muscles.

    PubMed

    Chia, Michael; Liao, Chin-An; Huang, Chih-Yang; Lee, Wen-Chih; Hou, Chien-Wen; Yu, Szu-Hsien; Harris, M Brennan; Hsu, Tung-Shiung; Lee, Shin-Da; Kuo, Chia-Hua

    2013-02-28

    Swimmers tend to have greater body fat than athletes from other sports. The purpose of the study was to examine changes in body composition after altitude hypoxia exposure and the role of blood distribution to the skeletal muscle in swimmers. With a constant training volume of 12.3 km/day, young male swimmers (N = 10, 14.8 ± 0.5 years) moved from sea-level to a higher altitude of 2,300 meters. Body composition was measured before and after translocation to altitude using dual-energy X-ray absorptiometry (DXA) along with 8 control male subjects who resided at sea level for the same period of time. To determine the effects of hypoxia on muscle blood perfusion, total hemoglobin concentration (THC) was traced by near-infrared spectroscopy (NIRS) in the triceps and quadriceps muscles under glucose-ingested and insulin-secreted conditions during hypoxia exposure (16% O2) after training. While no change in body composition was found in the control group, subjects who trained at altitude had unequivocally decreased fat mass (-1.7 ± 0.3 kg, -11.4%) with increased lean mass (+0.8 ± 0.2 kg, +1.5%). Arterial oxygen saturation significantly decreased with increased plasma lactate during hypoxia recovery mimicking 2,300 meters at altitude (~93% versus ~97%). Intriguingly, hypoxia resulted in elevated muscle THC, and sympathetic nervous activities occurred in parallel with greater-percent oxygen saturation in both muscle groups. In conclusion, the present study provides evidence that increased blood distribution to the skeletal muscle under postprandial condition may contribute to the reciprocally increased muscle mass and decreased body mass after a 3-week altitude exposure in swimmers.

  6. High altitude bird migration at temperate latitudes: a synoptic perspective on wind assistance.

    PubMed

    Dokter, Adriaan M; Shamoun-Baranes, Judy; Kemp, Michael U; Tijm, Sander; Holleman, Iwan

    2013-01-01

    At temperate latitudes the synoptic patterns of bird migration are strongly structured by the presence of cyclones and anticyclones, both in the horizontal and altitudinal dimensions. In certain synoptic conditions, birds may efficiently cross regions with opposing surface wind by choosing a higher flight altitude with more favourable wind. We observed migratory passerines at mid-latitudes that selected high altitude wind optima on particular nights, leading to the formation of structured migration layers at varying altitude up to 3 km. Using long-term vertical profiling of bird migration by C-band Doppler radar in the Netherlands, we find that such migration layers occur nearly exclusively during spring migration in the presence of a high-pressure system. A conceptual analytic framework providing insight into the synoptic patterns of wind assistance for migrants that includes the altitudinal dimension has so far been lacking. We present a simple model for a baroclinic atmosphere that relates vertical profiles of wind assistance to the pressure and temperature patterns occurring at temperate latitudes. We show how the magnitude and direction of the large scale horizontal temperature gradient affects the relative gain in wind assistance that migrants obtain through ascending. Temperature gradients typical for northerly high-pressure systems in spring are shown to cause high altitude wind optima in the easterly sectors of anticyclones, thereby explaining the frequent observations of high altitude migration in these synoptic conditions. Given the recurring synoptic arrangements of pressure systems across temperate continents, the opportunities for exploiting high altitude wind will differ between flyways, for example between easterly and westerly oceanic coasts.

  7. High Altitude Bird Migration at Temperate Latitudes: A Synoptic Perspective on Wind Assistance

    PubMed Central

    Dokter, Adriaan M.; Shamoun-Baranes, Judy; Kemp, Michael U.; Tijm, Sander; Holleman, Iwan

    2013-01-01

    At temperate latitudes the synoptic patterns of bird migration are strongly structured by the presence of cyclones and anticyclones, both in the horizontal and altitudinal dimensions. In certain synoptic conditions, birds may efficiently cross regions with opposing surface wind by choosing a higher flight altitude with more favourable wind. We observed migratory passerines at mid-latitudes that selected high altitude wind optima on particular nights, leading to the formation of structured migration layers at varying altitude up to 3 km. Using long-term vertical profiling of bird migration by C-band Doppler radar in the Netherlands, we find that such migration layers occur nearly exclusively during spring migration in the presence of a high-pressure system. A conceptual analytic framework providing insight into the synoptic patterns of wind assistance for migrants that includes the altitudinal dimension has so far been lacking. We present a simple model for a baroclinic atmosphere that relates vertical profiles of wind assistance to the pressure and temperature patterns occurring at temperate latitudes. We show how the magnitude and direction of the large scale horizontal temperature gradient affects the relative gain in wind assistance that migrants obtain through ascending. Temperature gradients typical for northerly high-pressure systems in spring are shown to cause high altitude wind optima in the easterly sectors of anticyclones, thereby explaining the frequent observations of high altitude migration in these synoptic conditions. Given the recurring synoptic arrangements of pressure systems across temperate continents, the opportunities for exploiting high altitude wind will differ between flyways, for example between easterly and westerly oceanic coasts. PMID:23300969

  8. Altitude variations in the thermosphere mass density response to geomagnetic activity during the recent solar minimum

    NASA Astrophysics Data System (ADS)

    Liu, X.; Thayer, J. P.; Burns, A.; Wang, W.; Sutton, E.

    2014-03-01

    Accelerometer data from coplanar orbits of Challenging Minisatellite Payload (CHAMP) and Gravity Recovery and Climate Experiment (GRACE) satellites were used to study the complex altitude and latitude variations of the thermosphere mass density response to geomagnetic activity during 1-10 December 2008 near 09 LT. Helium number densities near 500 km altitude were extracted from the CHAMP and GRACE measurements and clearly show the presence of a winter hemisphere helium bulge. This recent extreme solar minimum indicates that wintertime helium concentrations exceed NRLMSISE-00 model estimates by 30%-70% during quiet geomagnetic activity after adjusting F10.7 input into MSIS. The perturbation in mass density from quiet to active conditions is found to be less enhanced in the winter hemisphere at the higher GRACE altitudes (25%) than at the lower CHAMP altitudes (60%) and is attributed to dynamic behavior in the helium/oxygen transition. The investigation revealed the maximum storm time density perturbation to occur near the He/O transition region with a much weaker maximum near the O/N2 transition region. The altitude of maximum density perturbation occurs where the perturbation in the weighted pressure scale height is equal and opposite to the perturbation in the weighted mean molecular weight scale height. The altitude structure of density scale height perturbation is significantly influenced by the changes in the molecular weight scale height and can account for 50% of the change in mass density scale height in a region correspondingly close to the He/O transition during the 2008 solar minimum period.

  9. Comparing the contributions of ionospheric outflow and high-altitude production to O+ loss at Mars

    NASA Astrophysics Data System (ADS)

    Liemohn, Michael; Curry, Shannon; Fang, Xiaohua; Johnson, Blake; Fraenz, Markus; Ma, Yingjuan

    2013-04-01

    The Mars total O+ escape rate is highly dependent on both the ionospheric and high-altitude source terms. Because of their different source locations, they appear in velocity space distributions as distinct populations. The Mars Test Particle model is used (with background parameters from the BATS-R-US magnetohydrodynamic code) to simulate the transport of ions in the near-Mars space environment. Because it is a collisionless model, the MTP's inner boundary is placed at 300 km altitude for this study. The MHD values at this altitude are used to define an ionospheric outflow source of ions for the MTP. The resulting loss distributions (in both real and velocity space) from this ionospheric source term are compared against those from high-altitude ionization mechanisms, in particular photoionization, charge exchange, and electron impact ionization, each of which have their own (albeit overlapping) source regions. In subsequent simulations, the MHD values defining the ionospheric outflow are systematically varied to parametrically explore possible ionospheric outflow scenarios. For the nominal MHD ionospheric outflow settings, this source contributes only 10% to the total O+ loss rate, nearly all via the central tail region. There is very little dependence of this percentage on the initial temperature, but a change in the initial density or bulk velocity directly alters this loss through the central tail. However, a density or bulk velocity increase of a factor of 10 makes the ionospheric outflow loss comparable in magnitude to the loss from the combined high-altitude sources. The spatial and velocity space distributions of escaping O+ are examined and compared for the various source terms, identifying features specific to each ion source mechanism. These results are applied to a specific Mars Express orbit and used to interpret high-altitude observations from the ion mass analyzer onboard MEX.

  10. Dietary Recommendations for Cyclists during Altitude Training

    PubMed Central

    Michalczyk, Małgorzata; Czuba, Miłosz; Zydek, Grzegorz; Zając, Adam; Langfort, Józef

    2016-01-01

    The concept of altitude or hypoxic training is a common practice in cycling. However, several strategies for training regimens have been proposed, like “live high, train high” (LH-TH), “live high, train low” (LH-TL) or “intermittent hypoxic training” (IHT). Each of them combines the effect of acclimatization and different training protocols that require specific nutrition. An appropriate nutrition strategy and adequate hydration can help athletes achieve their fitness and performance goals in this unfriendly environment. In this review, the physiological stress of altitude exposure and training will be discussed, with specific nutrition recommendations for athletes training under such conditions. However, there is little research about the nutrition demands of athletes who train at moderate altitude. Our review considers energetic demands and body mass or body composition changes due to altitude training, including respiratory and urinary water loss under these conditions. Carbohydrate intake recommendations and hydration status are discussed in detail, while iron storage and metabolism is also considered. Last, but not least the risk of increased oxidative stress under hypoxic conditions and antioxidant supplementation suggestions are presented. PMID:27322318

  11. Altitude Wind Tunnel Operating at Night

    NASA Image and Video Library

    1945-04-21

    The Altitude Wind Tunnel (AWT) during one of its overnight runs at the National Advisory Committee for Aeronautics (NACA) Aircraft Engine Research Laboratory in Cleveland, Ohio. The AWT was run during night hours so that its massive power loads were handled when regional electric demands were lowest. At the time the AWT was among the most complex wind tunnels ever designed. In order to simulate conditions at high altitudes, NACA engineers designed innovative new systems that required tremendous amounts of electricity. The NACA had an agreement with the local electric company that it would run its larger facilities overnight when local demand was at its lowest. In return the utility discounted its rates for the NACA during those hours. The AWT could produce wind speeds up to 500 miles per hour through its 20-foot-diameter test section at the standard operating altitude of 30,000 feet. The airflow was created by a large fan that was driven by an 18,000-horsepower General Electric induction motor. The altitude simulation was accomplished by large exhauster and refrigeration systems. The cold temperatures were created by 14 Carrier compressors and the thin atmosphere by four 1750-horsepower exhausters. The first and second shifts usually set up and broke down the test articles, while the third shift ran the actual tests. Engineers would often have to work all day, then operate the tunnel overnight, and analyze the data the next day. The night crew usually briefed the dayshift on the tests during morning staff meetings.

  12. Altitude Adaptation: A Glimpse Through Various Lenses.

    PubMed

    Simonson, Tatum S

    2015-06-01

    Simonson, Tatum S. Altitude adaptation: A glimpse through various lenses. High Alt Med Biol 16:125-137, 2015.--Recent availability of genome-wide data from highland populations has enabled the identification of adaptive genomic signals. Some of the genomic signals reported thus far among Tibetan, Andean, and Ethiopian are the same, while others appear unique to each population. These genomic findings parallel observations conveyed by decades of physiological research: different continental populations, resident at high altitude for hundreds of generations, exhibit a distinct composite of traits at altitude. The most commonly reported signatures of selection emanate from genomic segments containing hypoxia-inducible factor (HIF) pathway genes. Corroborative evidence for adaptive significance stems from associations between putatively adaptive gene copies and sea-level ranges of hemoglobin concentration in Tibetan and Amhara Ethiopians, birth weights and metabolic factors in Andeans and Tibetans, maternal uterine artery diameter in Andeans, and protection from chronic mountain sickness in Andean males at altitude. While limited reports provide mechanistic insights thus far, efforts to identify and link precise genetic variants to molecular, physiological, and developmental functions are underway, and progress on the genomics front continues to provide unprecedented movement towards these goals. This combination of multiple perspectives is necessary to maximize our understanding of orchestrated biological and evolutionary processes in native highland populations, which will advance our understanding of both adaptive and non-adaptive responses to hypoxia.

  13. The morbid anatomy of high altitude

    PubMed Central

    Heath, Donald

    1979-01-01

    The morbid anatomical changes which take place in man and animals exposed to the chronic hypoxia of residence at high altitude are briefly reviewed. ImagesFig. 1Fig. 2Fig. 3Fig. 5Fig. 4Fig. 6Fig. 7Fig. 8 PMID:493205

  14. SRB Altitude Switch Assembly Wire Harness Failure

    NASA Technical Reports Server (NTRS)

    Blanche, Jim

    2002-01-01

    This paper presents an assessment of two wire harness failures that had occurred in Solid Rocket Booster Altitude Switch Assemblies S/N 200001 and S/N 20002. A list of modifications to EDU #4 and modification of qualification units 2000001 and 2000002 are also presented.

  15. 78 FR 32979 - IFR Altitudes; Miscellaneous Amendments

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-06-03

    ..., or direct routes for which a minimum or maximum en route authorized IFR altitude is prescribed. This regulatory action is needed because of changes occurring in the National Airspace System. These changes are... (COPs) for Federal airways, jet routes, or direct routes as prescribed in part 95. The Rule The...

  16. Altitude Preexposure Recommendations for Inducing Acclimatization

    DTIC Science & Technology

    2010-01-01

    acetazolamide ( Kronenberg and Cain, 1968). Acute exposure to high altitude increases heart rate and cardiac output to maintain systemic oxygen delivery...emphasizing the regulation of breathing. Physiologist. 11:37–57. Kronenberg R.S., and Cain S.M. (1968). Hastening respiratory acclimatization to

  17. Breathing and sleep at high altitude.

    PubMed

    Ainslie, Philip N; Lucas, Samuel J E; Burgess, Keith R

    2013-09-15

    We provide an updated review on the current understanding of breathing and sleep at high altitude in humans. We conclude that: (1) progressive changes in pH initiated by the respiratory alkalosis do not underlie early (<48 h) ventilatory acclimatization to hypoxia (VAH) because this still proceeds in the absence of such alkalosis; (2) for VAH of longer duration (>48 h), complex cellular and neurochemical re-organization occurs both in the peripheral chemoreceptors as well as within the central nervous system. The latter is likely influenced by central acid-base changes secondary to the extent of the initial respiratory responses to initial exposure to high altitude; (3) sleep at high altitude is disturbed by various factors, but principally by periodic breathing; (4) the extent of periodic breathing during sleep at altitude intensifies with duration and severity of exposure; (5) complex interactions between hypoxic-induced enhancement in peripheral and central chemoreflexes and cerebral blood flow--leading to higher loop gain and breathing instability--underpin this development of periodic breathing during sleep; (6) because periodic breathing may elevate rather than reduce mean SaO2 during sleep, this may represent an adaptive rather than maladaptive response; (7) although oral acetazolamide is an effective means to reduce periodic breathing by 50-80%, recent studies using positive airway pressure devices to increase dead space, hyponotics and theophylline are emerging but appear less practical and effective compared to acetazolamide. Finally, we suggest avenues for future research, and discuss implications for understanding sleep pathology.

  18. High-altitude solar power platform

    SciTech Connect

    Bailey, M.D.; Bower, M.V.

    1992-04-01

    Solar power is a preeminent alternative to conventional aircraft propulsion. With the continued advances in solar cells, fuel cells, and composite materials technology, the solar powered airplane is no longer a simple curiosity constrained to flights of several feet in altitude or minutes of duration. A high altitude solar powered platform (HASPP) has several potential missions, including communications and agriculture. In remote areas, a HASPP could be used as a communication link. In large farming areas, a HASPP could perform remote sensing of crops. The impact of HASPP in continuous flight for one year on agricultural monitoring mission is presented. This mission provides farmers with near real-time data twice daily from an altitude which allows excellant resolution on water conditions, crop diseases, and insect infestation. Accurate, timely data will enable farmers to increase their yield and efficiency. A design for HASPP for the foregoing mission is presented. In the design power derived from solar cells covering the wings is used for propulsion, avionics, and sensors. Excess power produced midday will be stored in fuel cells for use at night to maintain altitude and course.

  19. Altitude Adaptation: A Glimpse Through Various Lenses

    PubMed Central

    2015-01-01

    Abstract Simonson, Tatum S. Altitude adaptation: A glimpse through various lenses. High Alt Med Biol 16:125–137, 2015.—Recent availability of genome-wide data from highland populations has enabled the identification of adaptive genomic signals. Some of the genomic signals reported thus far among Tibetan, Andean, and Ethiopian are the same, while others appear unique to each population. These genomic findings parallel observations conveyed by decades of physiological research: different continental populations, resident at high altitude for hundreds of generations, exhibit a distinct composite of traits at altitude. The most commonly reported signatures of selection emanate from genomic segments containing hypoxia-inducible factor (HIF) pathway genes. Corroborative evidence for adaptive significance stems from associations between putatively adaptive gene copies and sea-level ranges of hemoglobin concentration in Tibetan and Amhara Ethiopians, birth weights and metabolic factors in Andeans and Tibetans, maternal uterine artery diameter in Andeans, and protection from chronic mountain sickness in Andean males at altitude. While limited reports provide mechanistic insights thus far, efforts to identify and link precise genetic variants to molecular, physiological, and developmental functions are underway, and progress on the genomics front continues to provide unprecedented movement towards these goals. This combination of multiple perspectives is necessary to maximize our understanding of orchestrated biological and evolutionary processes in native highland populations, which will advance our understanding of both adaptive and non-adaptive responses to hypoxia. PMID:26070057

  20. Sickle Cell Trait, Exercise, and Altitude.

    ERIC Educational Resources Information Center

    Eichner, Edward R.

    1986-01-01

    Sickle cell trait is generally benign and does not shorten life, but it may confer some small risk with extremes of exercise or altitude. Research concerning these risks is presented, and it is concluded sickle cell trait is no barrier to outstanding athletic performance. (Author/MT)