Science.gov

Sample records for aircraft elevation measurements

  1. Aircraft Wake RCS Measurement

    NASA Technical Reports Server (NTRS)

    Gilson, William H.

    1994-01-01

    A series of multi-frequency radar measurements of aircraft wakes at altitudes of 5,000 to 25,00 ft. were performed at Kwajalein, R.M.I., in May and June of 1990. Two aircraft were tested, a Learjet 35 and a Lockheed C-5A. The cross-section of the wake of the Learjet was too small for detection at Kwajalein. The wake of the C-5A, although also very small, was detected and measured at VHF, UHF, L-, S-, and C-bands, at distances behind the aircraft ranging from about one hundred meters to tens of kilometers. The data suggest that the mechanism by which aircraft wakes have detectable radar signatures is, contrary to previous expectations, unrelated to engine exhaust but instead due to turbulent mixing by the wake vortices of pre-existing index of refraction gradients in the ambient atmosphere. These measurements were of necessity performed with extremely powerful and sensitive instrumentation radars, and the wake cross-section is too small for most practical applications.

  2. Advanced composite elevator for Boeing 727 aircraft

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Detail design activities are reported for a program to develop an advanced composites elevator for the Boeing 727 commercial transport. Design activities include discussion of the full scale ground test and flight test activities, the ancillary test programs, sustaining efforts, weight status, and the production status. Prior to flight testing of the advanced composites elevator, ground, flight flutter, and stability and control test plans were reviewed and approved by the FAA. Both the ground test and the flight test were conducted according to the approved plan, and were witnessed by the FAA. Three and one half shipsets have now been fabricated without any significant difficulty being encountered. Two elevator system shipsets were weighed, and results validated the 26% predicted weight reduction. The program is on schedule.

  3. Aircraft Lightning Electromagnetic Environment Measurement

    NASA Technical Reports Server (NTRS)

    Ely, Jay J.; Nguyen, Truong X.; Szatkowski, George N.

    2011-01-01

    This paper outlines a NASA project plan for demonstrating a prototype lightning strike measurement system that is suitable for installation onto research aircraft that already operate in thunderstorms. This work builds upon past data from the NASA F106, FAA CV-580, and Transall C-180 flight projects, SAE ARP5412, and the European ILDAS Program. The primary focus is to capture airframe current waveforms during attachment, but may also consider pre and post-attachment current, electric field, and radiated field phenomena. New sensor technologies are being developed for this system, including a fiber-optic Faraday polarization sensor that measures lightning current waveforms from DC to over several Megahertz, and has dynamic range covering hundreds-of-volts to tens-of-thousands-of-volts. A study of the electromagnetic emission spectrum of lightning (including radio wave, microwave, optical, X-Rays and Gamma-Rays), and a compilation of aircraft transfer-function data (including composite aircraft) are included, to aid in the development of other new lightning environment sensors, their placement on-board research aircraft, and triggering of the onboard instrumentation system. The instrumentation system will leverage recent advances in high-speed, high dynamic range, deep memory data acquisition equipment, and fiber-optic interconnect.

  4. TEPC measurements in commercial aircraft.

    PubMed

    Taylor, G C; Bentley, R D; Horwood, N A; Hunter, R; Iles, R H; Jones, J B L; Powell, D; Thomas, D J

    2004-01-01

    The collaborative project involving the Mullard Space Science Laboratory (MSSL), Virgin Atlantic Airways (VAA), the UK Civil Aviation Authority (CAA) and the UK National Physical Laboratory (NPL) has been performing tissue-equivalent proportional counter measurements of cosmic ray doses in commercial aircraft since January 2000. In that time data have been recorded on over 700 flights, including over 150 flights with Air New Zealand (ANZ). This substantial set of data from the southern hemisphere is an ideal complement to the London-based measurements performed primarily on VAA flights. Although some ANZ data remains to be analysed, dose information from 111 flights has been compared with the CARI and EPCARD computer codes. Overall, the agreement between the measurements and EPCARD was excellent (within 1% for the total ambient dose equivalent), and the difference in the total effective doses predicted by EPCARD and CARI was <5%.

  5. Measurement of In-Flight Aircraft Emissions

    NASA Technical Reports Server (NTRS)

    Sokoloski, M.; Arnold, C.; Rider, D.; Beer, R.; Worden, H.; Glavich, T.

    1995-01-01

    Aircraft engine emission and their chemical and physical evolution can be measured in flight using high resolution infrared spectroscopy. The Airborne Emission Spectrometer (AES), designed for remote measure- ments of atmosphere emissions from an airborne platform, is an ideal tool for the evaluation of aircraft emissions and their evolution. Capabilities of AES will be discussed. Ground data will be given.

  6. Small Aircraft RF Interference Path Loss Measurements

    NASA Technical Reports Server (NTRS)

    Nguyen, Truong X.; Koppen, Sandra V.; Ely, Jay J.; Szatkowski, George N.; Mielnik, John J.; Salud, Maria Theresa P.

    2007-01-01

    Interference to aircraft radio receivers is an increasing concern as more portable electronic devices are allowed onboard. Interference signals are attenuated as they propagate from inside the cabin to aircraft radio antennas mounted on the outside of the aircraft. The attenuation level is referred to as the interference path loss (IPL) value. Significant published IPL data exists for transport and regional category airplanes. This report fills a void by providing data for small business/corporate and general aviation aircraft. In this effort, IPL measurements are performed on ten small aircraft of different designs and manufacturers. Multiple radio systems are addressed. Along with the typical worst-case coupling values, statistical distributions are also reported that could lead to more meaningful interference risk assessment.

  7. Instrument for Aircraft-Icing and Cloud-Physics Measurements

    NASA Technical Reports Server (NTRS)

    Lilie, Lyle; Bouley, Dan; Sivo, Chris

    2006-01-01

    The figure shows a compact, rugged, simple sensor head that is part of an instrumentation system for making measurements to characterize the severity of aircraft-icing conditions and/or to perform research on cloud physics. The quantities that are calculated from measurement data acquired by this system and that are used to quantify the severity of icing conditions include sizes of cloud water drops, cloud liquid water content (LWC), cloud ice water content (IWC), and cloud total water content (TWC). The sensor head is mounted on the outside of an aircraft, positioned and oriented to intercept the ambient airflow. The sensor head consists of an open housing that is heated in a controlled manner to keep it free of ice and that contains four hot-wire elements. The hot-wire sensing elements have different shapes and sizes and, therefore, exhibit different measurement efficiencies with respect to droplet size and water phase (liquid, frozen, or mixed). Three of the hot-wire sensing elements are oriented across the airflow so as to intercept incoming cloud water. For each of these elements, the LWC or TWC affects the power required to maintain a constant temperature in the presence of cloud water.

  8. Design of a powered elevator control system. [powered elevator system for modified C-8A aircraft for STOL operation

    NASA Technical Reports Server (NTRS)

    Glende, W. L. B.

    1974-01-01

    The design, fabrication and flight testing of a powered elevator system for the Augmentor Wing Jet STOL Research Aircraft (AWJSRA or Mod C-8A) are discussed. The system replaces a manual spring tab elevator control system that was unsatisfactory in the STOL flight regime. Pitch control in the AWJSRA is by means of a single elevator control surface. The elevator is used for both maneuver and trim control as the stabilizer is fixed. A fully powered, irreversible flight control system powered by dual hydraulic sources was designed. The existing control columns and single mechanical cable system of the AWJSRA have been retained as has been the basic elevator surface, except that the elevator spring tab is modified into a geared balance tab. The control surface is directly actuated by a dual tandem moving body actuator. Control signals are transmitted from the elevator aft quadrant to the actuator by a linkage system that includes a limited authority series servo actuator.

  9. Recommendations for field measurements of aircraft noise

    NASA Technical Reports Server (NTRS)

    Marsh, A. H.

    1982-01-01

    Specific recommendations for environmental test criteria, data acquisition procedures, and instrument performance requirements for measurement of noise levels produced by aircraft in flight are provided. Recommendations are also given for measurement of associated airplane and engine parameters and atmospheric conditions. Recommendations are based on capabilities which were available commercially in 1981; they are applicable to field tests of aircraft flying subsonically past microphones located near the surface of the ground either directly under or to the side of a flight path. Aircraft types covered by the recommendations include fixed-wing airplanes powered by turbojet or turbofan engines or by propellers. The recommended field-measurement procedures are consistent with assumed requirements for data processing and analysis.

  10. Skin friction measuring device for aircraft

    NASA Technical Reports Server (NTRS)

    Montoya, L. C.; Bellman, D. R. (Inventor)

    1980-01-01

    A skin friction measuring device for measuring the resistance of an aerodynamic surface to an airstream is described. It was adapted to be mounted on an aircraft and is characterized by a friction plate adapted to be disposed in a flush relationship with the external surface of the aircraft and be displaced in response to skin friction drag. As an airstream is caused to flow over the surface, a potentiometer connected to the plate for providing an electrical output indicates the magnitude of the drag.

  11. Measurement of surface scratches on aircraft structures

    NASA Astrophysics Data System (ADS)

    Sarr, Dennis P.

    1996-01-01

    In assuring the quality of aircraft, the skin quality must be free of surface imperfections. Surface imperfections such as scratches are unacceptable for cosmetic and structural reasons. Scratches beyond a certain depth are not repairable, resulting in costly replacement of an aircraft's part. Measurements of aircraft exterior surfaces require a ladder or cherry picker for positioning the inspector. Commercially-available computer vision systems are not portable, easy to use, or ergonomic. The machine vision system must be designed with these criteria in mind. The scratch measurement system (SMS) uses computer vision, digital signal processing, and automated inspection methods. The system is portable and battery powered. It is certified for measuring the depth and width of the anomaly. The SMS provides a comprehensive, analytical, and accurate reading. A hardcopy output provides a permanent record of the analysis. The graphical data shows the surface profile and provides substantial information of the surface anomaly. The factory and flight line use the SMS at different stages of aircraft production. Six systems have been built for use within Boeing. A patent was issued for the SMS in February 1994.

  12. Remote measurement of pollution from aircraft

    NASA Technical Reports Server (NTRS)

    Reichle, H. G., Jr.

    1976-01-01

    This paper discusses the problem of the remote measurement of tropospheric air pollution from aircraft platforms. Following a discussion of the energy sources available for passive remote sensing and the location of the absorption bands of the gases, it describes the spectral resolution that would be required and the relative merits of the shorter and longer infrared wavelengths. It then traces the evolution of one instrument concept (the gas filter correlation radiometer) to its present state, and describes flight results that show the technique to be capable of measuring carbon monoxide over water. A new instrument is described that will allow the measurements to be extended to areas over land.

  13. Advanced composite elevator for Boeing 727 aircraft, volume 2

    NASA Technical Reports Server (NTRS)

    Chovil, D. V.; Grant, W. D.; Jamison, E. S.; Syder, H.; Desper, O. E.; Harvey, S. T.; Mccarty, J. E.

    1980-01-01

    Preliminary design activity consisted of developing and analyzing alternate design concepts and selecting the optimum elevator configuration. This included trade studies in which durability, inspectability, producibility, repairability, and customer acceptance were evaluated. Preliminary development efforts consisted of evaluating and selecting material, identifying ancillary structural development test requirements, and defining full scale ground and flight test requirements necessary to obtain Federal Aviation Administration (FAA) certification. After selection of the optimum elevator configuration, detail design was begun and included basic configuration design improvements resulting from manufacturing verification hardware, the ancillary test program, weight analysis, and structural analysis. Detail and assembly tools were designed and fabricated to support a full-scope production program, rather than a limited run. The producibility development programs were used to verify tooling approaches, fabrication processes, and inspection methods for the production mode. Quality parts were readily fabricated and assembled with a minimum rejection rate, using prior inspection methods.

  14. Aircraft

    DOEpatents

    Hibbs, B.D.; Lissaman, P.B.S.; Morgan, W.R.; Radkey, R.L.

    1998-09-22

    This disclosure provides a solar rechargeable aircraft that is inexpensive to produce, is steerable, and can remain airborne almost indefinitely. The preferred aircraft is a span-loaded flying wing, having no fuselage or rudder. Travelling at relatively slow speeds, and having a two-hundred foot wingspan that mounts photovoltaic cells on most all of the wing`s top surface, the aircraft uses only differential thrust of its eight propellers to turn. Each of five sections of the wing has one or more engines and photovoltaic arrays, and produces its own lift independent of the other sections, to avoid loading them. Five two-sided photovoltaic arrays, in all, are mounted on the wing, and receive photovoltaic energy both incident on top of the wing, and which is incident also from below, through a bottom, transparent surface. The aircraft is capable of a top speed of about ninety miles per hour, which enables the aircraft to attain and can continuously maintain altitudes of up to sixty-five thousand feet. Regenerative fuel cells in the wing store excess electricity for use at night, such that the aircraft can sustain its elevation indefinitely. A main spar of the wing doubles as a pressure vessel that houses hydrogen and oxygen gases for use in the regenerative fuel cell. The aircraft has a wide variety of applications, which include weather monitoring and atmospheric testing, communications, surveillance, and other applications as well. 31 figs.

  15. Aircraft

    DOEpatents

    Hibbs, Bart D.; Lissaman, Peter B. S.; Morgan, Walter R.; Radkey, Robert L.

    1998-01-01

    This disclosure provides a solar rechargeable aircraft that is inexpensive to produce, is steerable, and can remain airborne almost indefinitely. The preferred aircraft is a span-loaded flying wing, having no fuselage or rudder. Travelling at relatively slow speeds, and having a two-hundred foot wingspan that mounts photovoltaic cells on most all of the wing's top surface, the aircraft uses only differential thrust of its eight propellers to turn. Each of five sections of the wing has one or more engines and photovoltaic arrays, and produces its own lift independent of the other sections, to avoid loading them. Five two-sided photovoltaic arrays, in all, are mounted on the wing, and receive photovoltaic energy both incident on top of the wing, and which is incident also from below, through a bottom, transparent surface. The aircraft is capable of a top speed of about ninety miles per hour, which enables the aircraft to attain and can continuously maintain altitudes of up to sixty-five thousand feet. Regenerative fuel cells in the wing store excess electricity for use at night, such that the aircraft can sustain its elevation indefinitely. A main spar of the wing doubles as a pressure vessel that houses hydrogen and oxygen gasses for use in the regenerative fuel cell. The aircraft has a wide variety of applications, which include weather monitoring and atmospheric testing, communications, surveillance, and other applications as well.

  16. Measurements of neutron radiation in aircraft.

    PubMed

    Vuković, B; Poje, M; Varga, M; Radolić, V; Miklavcić, I; Faj, D; Stanić, D; Planinić, J

    2010-12-01

    Radiation environment is a complex mixture of charged particles of the solar and galactic origin, as well as of secondary particles created in an interaction of galactic cosmic particles with the nuclei of the Earth's atmosphere. A radiation field at aircraft altitude consists of different types of particles, mainly photons, electrons, positrons and neutrons, with a large energy range. In order to measure a neutron component of the cosmic radiation, we investigated a few combinations of a track etch detector (CR-39, LR-115) with a plastic converter or boron foil. Detector calibration was performed on neutrons coming from the nuclear reactor, as well as in the CERN-EU high-energy Reference Field (CERF) facility. From November 2007 to September 2008, the neutron dose equivalent was measured by the track detectors during five aircraft flights, in the north geographical latitude from 21° to 58°; the respective average dose rate, determined by using the D-4 detector (CR-39/B), was Ḣ(n)=5.9 μSv/h. The photon dose rate, measured by the electronic dosimeter RAD-60 SE, had the average value of Ḣ(f)=1.4 μSv/h.

  17. Elevation correction factor for absolute pressure measurements

    NASA Technical Reports Server (NTRS)

    Panek, Joseph W.; Sorrells, Mark R.

    1996-01-01

    With the arrival of highly accurate multi-port pressure measurement systems, conditions that previously did not affect overall system accuracy must now be scrutinized closely. Errors caused by elevation differences between pressure sensing elements and model pressure taps can be quantified and corrected. With multi-port pressure measurement systems, the sensing elements are connected to pressure taps that may be many feet away. The measurement system may be at a different elevation than the pressure taps due to laboratory space or test article constraints. This difference produces a pressure gradient that is inversely proportional to height within the interface tube. The pressure at the bottom of the tube will be higher than the pressure at the top due to the weight of the tube's column of air. Tubes with higher pressures will exhibit larger absolute errors due to the higher air density. The above effect is well documented but has generally been taken into account with large elevations only. With error analysis techniques, the loss in accuracy from elevation can be easily quantified. Correction factors can be applied to maintain the high accuracies of new pressure measurement systems.

  18. Power Measurement Errors on a Utility Aircraft

    NASA Technical Reports Server (NTRS)

    Bousman, William G.

    2002-01-01

    Extensive flight test data obtained from two recent performance tests of a UH 60A aircraft are reviewed. A power difference is calculated from the power balance equation and is used to examine power measurement errors. It is shown that the baseline measurement errors are highly non-Gaussian in their frequency distribution and are therefore influenced by additional, unquantified variables. Linear regression is used to examine the influence of other variables and it is shown that a substantial portion of the variance depends upon measurements of atmospheric parameters. Correcting for temperature dependence, although reducing the variance in the measurement errors, still leaves unquantified effects. Examination of the power difference over individual test runs indicates significant errors from drift, although it is unclear how these may be corrected. In an idealized case, where the drift is correctable, it is shown that the power measurement errors are significantly reduced and the error distribution is Gaussian. A new flight test program is recommended that will quantify the thermal environment for all torque measurements on the UH 60. Subsequently, the torque measurement systems will be recalibrated based on the measured thermal environment and a new power measurement assessment performed.

  19. Measurement of hydrogen peroxide from aircraft

    SciTech Connect

    Kok, G.L.

    1980-01-01

    Hydrogen peroxide (H/sub 2/O/sub 2/) is an important species in both the homogeneous and the heterogeneous chemistry of the troposphere. Measurement of H/sub 2/O/sub 2/ from aircraft provides information on the distribution of H/sub 2/O/sub 2/ in the troposphere and provides a great deal of additional information which cannot be obtained from ground-based measurements. Three analytical techniques for atmospheric H/sub 2/O/sub 2/ are available. Two of these are colorimetric methods involving the formation of a colored complex with titanium salt. In 1978, a chemiluminescent method for the determination of atmospheric H/sub 2/O/sub 2/ was introduced. This method involves the reaction of H/sub 2/O/sub 2/ with luminol in the presence of a copper catalyst, with the chemiluminescence serving as the basis of the analytical reaction.

  20. Advanced composite elevator for Boeing 727 aircraft. Volume 1: Technical summary

    NASA Technical Reports Server (NTRS)

    Chovil, D. V.; Harvey, S. T.; Mccarty, J. E.; Desper, O. E.; Jamison, E. S.; Syder, H.

    1981-01-01

    The design, development, analysis, and testing activities and results that were required to produce five and one-half shipsets of advanced composite elevators for Boeing 727 aircraft are summarized. During the preliminary design period, alternative concepts were developed. After selection of the best design, detail design and basic configuration improvements were evaluated. Five and one-half shipsets were manufactured. All program goals (except competitive cost demonstration) were accomplished when our design met or exceeded all requirements, criteria, and objectives.

  1. Guide to measurement of winds with instrumented aircraft

    NASA Technical Reports Server (NTRS)

    Frost, Walter; Paige, Terry S.; Nelius, Andrew E.

    1991-01-01

    Aircraft measurement techniques are reviewed. Review of past and present applications of instrument aircraft to atmospheric observations is presented. Questions to be answered relative to measuring mean wind profiles as contrasted to turbulence measurements are then addressed. Requirements of instrumentation and accuracy, data reduction, data acquisition, and theoretical and certainty analysis are considered.

  2. Estimating the abundance of airborne pollen and fungal spores at variable elevations using an aircraft: how high can they fly?

    NASA Astrophysics Data System (ADS)

    Damialis, Athanasios; Kaimakamis, Evangelos; Konoglou, Maria; Akritidis, Ioannis; Traidl-Hoffmann, Claudia; Gioulekas, Dimitrios

    2017-03-01

    Airborne pollen and fungal spores are monitored mainly in highly populated, urban environments, for allergy prevention purposes. However, their sources can frequently be located outside cities’ fringes with more vegetation. So as to shed light to this paradox, we investigated the diversity and abundance of airborne pollen and fungal spores at various environmental regimes. We monitored pollen and spores using an aircraft and a car, at elevations from sea level to 2,000 m above ground, in the region of Thesssaloniki, Greece. We found a total of 24 pollen types and more than 15 spore types. Pollen and spores were detected throughout the elevational transect. Lower elevations exhibited higher pollen concentrations in only half of plant taxa and higher fungal spore concentrations in only Ustilago. Pinaceae and Quercus pollen were the most abundant recorded by airplane (>54% of the total). Poaceae pollen were the most abundant via car measurements (>77% of the total). Cladosporium and Alternaria spores were the most abundant in all cases (aircraft: >69% and >17%, car: >45% and >27%, respectively). We conclude that pollen and fungal spores can be diverse and abundant even outside the main source area, evidently because of long-distance transport incidents.

  3. Estimating the abundance of airborne pollen and fungal spores at variable elevations using an aircraft: how high can they fly?

    PubMed Central

    Damialis, Athanasios; Kaimakamis, Evangelos; Konoglou, Maria; Akritidis, Ioannis; Traidl-Hoffmann, Claudia; Gioulekas, Dimitrios

    2017-01-01

    Airborne pollen and fungal spores are monitored mainly in highly populated, urban environments, for allergy prevention purposes. However, their sources can frequently be located outside cities’ fringes with more vegetation. So as to shed light to this paradox, we investigated the diversity and abundance of airborne pollen and fungal spores at various environmental regimes. We monitored pollen and spores using an aircraft and a car, at elevations from sea level to 2,000 m above ground, in the region of Thesssaloniki, Greece. We found a total of 24 pollen types and more than 15 spore types. Pollen and spores were detected throughout the elevational transect. Lower elevations exhibited higher pollen concentrations in only half of plant taxa and higher fungal spore concentrations in only Ustilago. Pinaceae and Quercus pollen were the most abundant recorded by airplane (>54% of the total). Poaceae pollen were the most abundant via car measurements (>77% of the total). Cladosporium and Alternaria spores were the most abundant in all cases (aircraft: >69% and >17%, car: >45% and >27%, respectively). We conclude that pollen and fungal spores can be diverse and abundant even outside the main source area, evidently because of long-distance transport incidents. PMID:28300143

  4. Aircraft

    DTIC Science & Technology

    2002-01-01

    Company, Washington, DC Boeing Commercial Aircraft Division, Seattle, WA and Long Beach, CA Boeing Military Aircraft and Missile Division, St. Louis, MO and... aircraft ; military fixed-wing aircraft ; rotorcraft (helicopters and tiltrotor aircraft ); and aircraft jet engines. Two companies dominate the commercial... aircraft business, Boeing and Airbus. Four companies dominate the military fixed-wing market, Boeing, Lockheed Martin, BAE Systems, and European

  5. Wide field of view laser beacon system for three-dimensional aircraft position measurement

    NASA Technical Reports Server (NTRS)

    Sweet, L. M.; Miles, R. B.; Webb, S. G.; Wong, E. Y.

    1981-01-01

    This paper presents a new wide field of view laser beacon system for measurement, in three dimensions, of aircraft or other remote objects. The system is developed for aircraft collision hazard warning independent of ground-based hardware, as well as for flight research, helicopter-assisted construction and rescue, and robotic manipulation applications. Accurate information describing the relative range, elevation, and azimuth of the aircraft are generated by the sweep of a low-power fan-shaped rotating laser beacon past an array of optical detectors. The system achieves a wide angle of acceptance of laser beacon light through use of compound parabolic concentrators, which collimate the light for spectral filtering to minimize solar interference. An on-board microprocessor system converts the pulse sequence to aircraft position in real time. System reliability and performance are enhanced through narrow pass filtering of the pulse signals, digital logic design to mask spurious signals, and adaptive modulation of trigger threshold levels.

  6. Aircraft water vapor measurements utilizing an aluminum oxide hygrometer

    NASA Technical Reports Server (NTRS)

    Hilsenrath, E.

    1973-01-01

    A hygrometer for water vapor measurements from an aircraft has been developed. An aluminum oxide hygrometer mounted in an aircraft Rosemount air temperature scoop was flown on NASA and USAF aircraft. Water vapor measurements were conducted up to 40,000 feet with penetration into the stratosphere. Good agreement was obtained with simultaneously flown remote sounders of water vapor. During transcontinental flights the hygrometer demonstrated adequate response to measure the natural variability of water vapor near the tropopause. Rapid response was demonstrated in pursuit of the jet wake of an F-104 at 35,000 feet.

  7. Aircraft water vapor measurements utilizing an aluminum oxide hygrometer

    NASA Technical Reports Server (NTRS)

    Hilsenrath, E.

    1974-01-01

    A hygrometer for water vapor measurements from an aircraft was developed. An aluminum oxide hygrometer mounted in an aircraft Rosemount air temperature scoop was flown on the NASA Convair 990 and on a USAF B-57 aircraft. Water vapor measurements from the Convair 990 were conducted up to 40,000 ft with penetration into the stratosphere. Good agreement was obtained with simultaneously flown remote sounders of water vapor. During transcontinental flights the hygrometer demonstrated adequate response to measure the natural variability of water vapor near the tropopause. Rapid response was demonstrated in pursuit of the jet wake of an F-104 at 35,000 ft.

  8. Instrumentation of sampling aircraft for measurement of launch vehicle effluents

    NASA Technical Reports Server (NTRS)

    Wornom, D. E.; Woods, D. C.; Thomas, M. E.; Tyson, R. W.

    1977-01-01

    An aircraft was selected and instrumented to measure effluents emitted from large solid propellant rockets during launch activities. The considerations involved in aircraft selection, sampling probes, and instrumentation are discussed with respect to obtaining valid airborne measurements. Discussions of the data acquisition system used, the instrument power system, and operational sampling procedures are included. Representative measurements obtained from an actual rocket launch monitoring activity are also presented.

  9. Aircraft body-axis rotation measurement system

    NASA Technical Reports Server (NTRS)

    Cowdin, K. T. (Inventor)

    1983-01-01

    A two gyro four gimbal attitude sensing system having gimbal lock avoidance is provided with continuous azimuth information, rather than roll information, relative to the magnetic cardinal headings while in near vertical attitudes to allow recovery from vertical on a desired heading. The system is comprised of a means for stabilizing an outer roll gimbal that is common to a vertical gyro and a directional gyro with respect to the aircraft platform which is being angularly displaced about an axis substantially parallel to the outer roll gyro axis. A means is also provided for producing a signal indicative of the magnitude of such displacement as an indication of aircraft heading. Additional means are provided to cause stabilization of the outer roll gimbal whenever the pitch angle of the aircraft passes through a threshold prior to entering vertical flight and destabilization of the outer roll gimbal upon passing through the threshold when departing vertical flight.

  10. Recommended procedures for measuring aircraft noise and associated parameters

    NASA Technical Reports Server (NTRS)

    Marsh, A. H.

    1977-01-01

    Procedures are recommended for obtaining experimental values of aircraft flyover noise levels (and associated parameters). Specific recommendations are made for test criteria, instrumentation performance requirements, data-acquisition procedures, and test operations. The recommendations are based on state-of-the-art measurement capabilities available in 1976 and are consistent with the measurement objectives of the NASA Aircraft Noise Prediction Program. The recommendations are applicable to measurements of the noise produced by an airplane flying subsonically over (or past) microphones located near the surface of the ground. Aircraft types covered by the recommendations are fixed-wing airplanes powered by turbojet or turbofan engines and using conventional aerodynamic means for takeoff and landing. Various assumptions with respect to subsequent data processing and analysis were made (and are described) and the recommended measurement procedures are compatible with the assumptions. Some areas where additional research is needed relative to aircraft flyover noise measurement techniques are also discussed.

  11. Measuring Wildfires From Aircraft And Satellites

    NASA Technical Reports Server (NTRS)

    Brass, J. A.; Arvesen, J. C.; Ambrosia, V. G.; Riggan, P. J.; Meyers, J. S.

    1991-01-01

    Aircraft and satellite systems yield wide-area views, providing total coverage of affected areas. System developed for use aboard aircraft includes digital scanner that records data in 12 channels. Transmits data to ground station for immediate use in fighting fires. Enables researchers to estimate gaseous and particulate emissions from fires. Provides information on temperatures of flame fronts and soils, intensities and rate of spread of fires, characteristics of fuels and smoke plumes, energy-release rates, and concentrations and movements of trace gases. Data relates to heating and cooling of soils, loss of nutrients, and effects on atmospheric, terrestrial, and aquatic systems.

  12. Ultrasonic Measurement of Aircraft Strut Hydraulic Fluid Level

    NASA Technical Reports Server (NTRS)

    Allison, Sidney G.

    2002-01-01

    An ultrasonic method is presented for non-intrusively measuring hydraulic fluid level in aircraft struts in the field quickly and easily without modifying the strut or aircraft. The technique interrogates the strut with ultrasonic waves generated and received by a removable ultrasonic transducer hand-held on the outside of the strut in a fashion that is in the presence or absence of hydraulic fluid inside the strut. This technique was successfully demonstrated on an A-6 aircraft strut on the carriage at the Aircraft Landing Dynamics Research Facility at NASA Langley Research Center. Conventional practice upon detection of strut problem symptoms is to remove aircraft from service for extensive maintenance to determine fluid level. No practical technique like the method presented herein for locating strut hydraulic fluid level is currently known to be used.

  13. Aircraft Transparency Optical Quality: New Methods of Measurement

    DTIC Science & Technology

    1981-02-01

    AFAMRL.TR-1-21 X AIRCRAFT TRANSPARENCY OPTICAL QUALITY: NEW METHODS OF MEASUREMENT LOUIS V. GENCO , O.D., Lt. Colonel HARRY L. TASK, Ph.D. FEBRUARY...aircraft transparency with simple modifications of a positioning fixture ( Genco , 1979). DESIRABLE CHARACTERISTICS The ideal field evaluation unit for...34Windscreen Angular Deviation Measurement Device," U.S. Air Force Invention No. 13647, Patent Pending. Task, Harry L., Louis V. Genco , and Kenneth L. Smith

  14. Using an A-10 Aircraft for Airborne measurements of TGFs

    NASA Technical Reports Server (NTRS)

    Fishman, Gerald J.; Christian, Hugh, J.; Blakeslee, Richard J.; Grove, J. Eric; Chektman, Alexandre; Jonsson, Haflidi; Detwiler, Andrew G.

    2012-01-01

    Plans are underway to convert an A-10 combat attack aircraft into a research aircraft for thunderstorm research. This aircraft would be configured and instrumented for flights into large, convective thunderstorms. It would have the capabilities of higher altitude performance and protection for thunderstorm conditions that exceed those of aircraft now in use for this research. One area of investigation for this aircraft would be terrestrial gamma ]ray flashes (TGFs), building on the pioneering observations made by the Airborne Detector for Energetic Lightning Emissions (ADELE) project several years ago. A new and important component of the planned investigations are the continuous, detailed correlations of TGFs with the electric fields near the aircraft, as well as detailed measurements of nearby lightning discharges. Together, the x-and gamma-radiation environments, the electric field measurements, and the lightning observations (all measured on microsecond timescales) should provide new insights into this TGF production mechanism. The A -10 aircraft is currently being modified for thunderstorm research. It is anticipated that the initial test flights for this role will begin next year.

  15. Aircraft measurements and analysis of severe storms: 1976 field experiment

    NASA Technical Reports Server (NTRS)

    Sinclair, P. C.

    1982-01-01

    Severe storm aircraft measurements are documented, as well as the instrumentation and operational features of aircraft mobility capabilities. The measurements and data analyses indicate that the concept of a highly mobile research aircraft capability for obtaining detailed measurements of wind, temperature, moisture, spherics, etc., near and within severe storm systems, forecast 48 hours in advance in a 1000 nm operating radius, is feasible, and was successfully demonstrated. The measurements and analyses reveal several severe storm features and insights with respect to storm air flow circulations and inflow-outflow orientation. Precipitation downdraft air is recirculated back into the updraft core below the scud cloud in both back and front feeder type storms. In a back feeder type storm, the downdraft outflow air ahead of the storm is also recirculated back into the updraft region near cloud base.

  16. Aircraft measurements and analysis of severe storms: 1975 field experiment

    NASA Technical Reports Server (NTRS)

    Sinclair, P. C.

    1976-01-01

    Three aircraft and instrumentation systems were acquired in support of the severe storm surveillance program. The data results indicate that the original concept of a highly mobile research aircraft capability for obtaining detailed measurements of wind, temperature, dew point, etc., near and within specifically designated severe storms is entirely feasible and has been demonstrated for the first time by this program. This program is unique in that it is designed to be highly mobile in order to move to and/or with the developing storm systems to obtain the necessary measurements. Previous programs have all been fixed to a particular location and therefore have had to wait for the storms to come within their network. The present research is designed around a highly mobile aircraft measurements group in order to maximize the storm cases during the field measurements program.

  17. Elimination of directional wave spectrum contamination from noise in elevation measurements

    NASA Technical Reports Server (NTRS)

    Walsh, E. J.; Hancock, D. W., III; Hines, D. E.; Swift, R. N.; Scott, J. F.

    1985-01-01

    The Surface Contour Radar (SCR) is a 36-GHz computer-controlled airborne radar which generates a false-color-coded elevation map of the sea surface below the aircraft in real time, and can routinely produce ocean directional wave spectra with post-flight data processing which have much higher angular resolution than pitch-and-roll buoys. The SCR range measurements are not error-free and the resulting errors in the elevations corrupt the directional wave spectrum. This paper presents a technique for eliminating that contamination.

  18. IAGOS : operational start of atmospheric measurements on commercial Airbus aircraft

    NASA Astrophysics Data System (ADS)

    Nedelec, P.

    2011-12-01

    AUTHORS : Philippe Nedelec 1, Jean-Pierre Cammas 1, Gilles Athier 1, Damien Boulanger 1, Jean-Marc Cousin 1., Andreas Volz-Thomas 2. 1. Laboratoire d' Aerologie, CNRS and University of Toulouse, Toulouse, France. 2. FZ Jülich, Jülich, Germany The MOZAIC program (http://mozaic.aero.obs-mip.fr) measures atmospheric parameters since August 1994, on board 5 commercial Airbus A340 aircraft operated by European airlines, with about 33 000 flights up to present. Three aircraft are still in operation and a new project has been sponsored by the European Community, and French and German national budgets. This project is called IAGOS for "In-service Aircraft for a Global Observing system" and can be considered as an update of Mozaic systems, increasing the performances and the measuring capacity. Plans are to equip 10-20 aircraft in the coming years to ensure a global coverage of the observations. Instrumentation has been developed by the participating partners and has been certified for installation on commercial passenger aircraft. The basic instrumentation includes O3, CO, H2O and clouds sensors, as well as the position and meteorological parameters acquired by the aircraft. One of the optional equipment can also be installed: NOx or NOy or CO2/CH4 or Aerosols. Data measured during flight are automatically transmitted after aircraft landing to CNRS reception centre in Toulouse, France, and made available to scientist some days later. The installation on a Lufthansa Airbus A340 has been finalised and certified by EASA (European Aviation Safety Agency) on July 7th, 2011 and operations started the following day, with data transmitted every landing to the CNRS centre. We will present technical details of the IAGOS aeronautic installation, measuring instruments of the basic system and some results of the first months of IAGOS operation.

  19. Optical measurements of degradation in aircraft boundary layers

    NASA Technical Reports Server (NTRS)

    Kelsall, D.

    1980-01-01

    Visible wavelength measurements of the degradation of optical beams when transmitted through the thin aerodynamic boundary layers around an aircraft are reviewed. The measured results indicated degradation levels for the KC-135 airplanes between 0.10 to 0.13 lambda increasing to 0.18 lambda (rms wavefront distortion). For the Lear Jet, degradation with a 25 mm diameter optics was roughly 0.07 lambda. The corresponding infinite aperture degradation levels are also calculated. The corresponding measured correlation lengths of roughly 12 mm for the KC-135 aircraft and 6 mm for the Lear Jet scale to roughly 20 and 25 mm, respectively, for infinite apertures. These boundary layer correlation lengths do not appear to reflect the different boundary layer thicknesses on the two different aircraft.

  20. Pilot Workload Measurement and Experience on Supersonic Cruise Aircraft

    NASA Technical Reports Server (NTRS)

    Rezek, T. W.

    1978-01-01

    Aircraft parameters and physiological parameters most indicative of crew workload were investigated. Recommendations were used to form the basis for a continuing study in which variations of the interval between heart beats are used as a measure of nonphysical workload. Preliminary results are presented and current efforts in further defining this physiological measure are outlined.

  1. Aircraft emission measurements by remote sensing methodologies at airports

    NASA Astrophysics Data System (ADS)

    Schäfer, Klaus; Jahn, Carsten; Sturm, Peter; Lechner, Bernhard; Bacher, Michael

    The emission indices of aircraft engine exhausts from measurements taken under operating conditions, to calculate precisely the emission inventories of airports, are not available up to now. To determine these data, measurement campaigns were performed on idling aircraft at major European airports using non-intrusive spectroscopic methods like Fourier transform infrared spectrometry and differential optical absorption spectroscopy. Emission indices for CO and NO x were calculated and compared to the values given in the International Civil Aviation Organisation (ICAO) database. The emission index for CO for 36 different aircraft engine types and for NO x (24 different engine types) were determined. It was shown that for idling aircraft, CO emissions are underestimated using the ICAO database. The emission indices for NO x determined in this work are lower than given in the ICAO database. In addition, a high variance of emission indices in each aircraft family and from engine to engine of the same engine type was found. During the same measurement campaigns, the emission indices for CO and NO of eight different types of auxilliary power units were investigated.

  2. Measurements of aircraft emissions indices at airports passive remote sensing

    NASA Astrophysics Data System (ADS)

    Schaefer, Klaus; Jahn, Carsten; Sturm, Peter J.; Lechner, Bernhard; Bacher, Michael

    2003-04-01

    The emission indices of aircraft engine exhausts to calculate precisely the emissions inventories of airports are not available up to now from measurements taken under operating conditions. To determine these data no installations nearby or behind the aircraft are possible at airports. That's why measurements by FTIR emission spectrometry were performed by the IMK-IFU with a spectrometer installed in a van and with total measurement time at one thrust level of about 1 minute to determine CO, NO and CO2. The FTIR instrument telescope was aligned to the engine nozzle exit of standing aircraft. A DOAS and a FTIR spectrometer with globar were used for simultaneous open-path measurements of NO, NO2, CO, CO2 and speciated hydrocarbons behind the aircraft by the TUG-VKMB. Measurement results at the airports Frankfurt/Main, London-Heathrow and Vienna are presented. The methods are evaluated by comparing CO emission indices from passive measurements with open-path data. The measured emission indices of CO show slightly higher values than the International Civil Aviation Organisation data sheets but less values for NOx emissions. A fruitful co-operation with the airlines AUA, BA and DLH as well as the airport authorities in Vienna and London-Heathrow supported this work which is financed from EC.

  3. Atmospheric mercury measurements onboard the CARIBIC passenger aircraft

    NASA Astrophysics Data System (ADS)

    Slemr, Franz; Weigelt, Andreas; Ebinghaus, Ralf; Kock, Hans H.; Bödewadt, Jan; Brenninkmeijer, Carl A. M.; Rauthe-Schöch, Armin; Weber, Stefan; Hermann, Markus; Becker, Julia; Zahn, Andreas; Martinsson, Bengt

    2016-05-01

    Goal of the project CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrumented Container) is to carry out regular and detailed observations of atmospheric composition (particles and gases) at cruising altitudes of passenger aircraft, i.e. at 9-12 km. Mercury has been measured since May 2005 by a modified Tekran instrument (Tekran Model 2537 A analyser, Tekran Inc., Toronto, Canada) during monthly intercontinental flights between Europe and South and North America, Africa, and Asia. Here we describe the instrument modifications, the post-flight processing of the raw instrument signal, and the fractionation experiments.

  4. A preliminary study of containment concepts for aircraft landing on elevated STOL-ports

    NASA Technical Reports Server (NTRS)

    Haviland, J. K.

    1971-01-01

    A preliminary study of containment systems for aircraft landing on elevated STOL-ports was conducted as part of an overall study of human acceptance problems associated with STOL operations. The study included a survey and feasibility study of different concepts and a computer analysis of four arrestment systems. The principal conclusion was that a system referred to as the FAA system appears to offer the greatest promise. In this system, standard arresting gear cables are stretched across the roof-top, at roughly 100-foot intervals, but are shielded over the 100-foot-wide primary landing strip. Thus a pilot can land with an arresting hook down, but will not contact the cable unless he swerves off the landing strip, either because he has made a bad landing, or because his landing gear has failed. It was also noted that a suitable curb or guard rail should be developed. Presently available arresting gears and nylon net barriers were considered satisfactory for the overshoot problem.

  5. Aircraft measurement of electric field - Self-calibration

    NASA Technical Reports Server (NTRS)

    Winn, W. P.

    1993-01-01

    Aircraft measurement of electric fields is difficult as the electrically conducting surface of the aircraft distorts the electric field. Calibration requires determining the relations between the undistorted electric field in the absence of the vehicle and the signals from electric field meters that sense the local distorted fields in their immediate vicinity. This paper describes a generalization of a calibration method which uses pitch and roll maneuvers. The technique determines both the calibration coefficients and the direction of the electric vector. The calibration of individual electric field meters and the elimination of the aircraft's self-charge are described. Linear combinations of field mill signals are examined and absolute calibration and error analysis are discussed. The calibration method was applied to data obtained during a flight near thunderstorms.

  6. Measurement of the frequency stability of responders in aircraft

    NASA Technical Reports Server (NTRS)

    Liu, Xiaofan

    1994-01-01

    Measurement on an aircraft orbit, such as a satellite launching orbit, is made by the responder in the aircraft along with several remote track stations on the ground. During the launching, the system is required to have precise time synchronization and frequency accuracy. At the same time, accurate measurement of aircraft velocity requires high frequency stability of the system. However, atomic frequency standards in the ground stations supply time and frequency reference standard with excellent long term and short term frequency stability for the above-mentioned goals. The stability of responder is also an important factor affecting the performance of the system and there are more requirements for the corresponding time/frequency measurements. In the system, the responders do not use continuous wave (CW) but narrow pulse modulated wave; consequently, the characterization theory of their stability is more complicated and the measurement technique is more difficult for pulsed wave than that for CW. A systematic characterization theory of the frequency stability for pulsed wave is demonstrated and the measuring methods are discussed. The measurement systems, which have been set up in Beijing Institute of Radio Metrology and Measurement (BIRMM) and can be used to test the frequency stability of pulse coherent responders in time domain and frequency domain with high sensitivity and accuracy, are described. Using these measurement systems, successful measurements for the responders were made with which the satellite launching orbits were precisely obtained and tracked.

  7. Regional studies of potential carbon monoxide sources based on Space Shuttle and aircraft measurements

    NASA Technical Reports Server (NTRS)

    Newell, R. E.; Shipley, S. T.; Connors, V. S.; Reichle, H. G., Jr.

    1988-01-01

    Carbon monoxide measurements made from the Space Shuttle show maxima over South America, central Africa, the eastern Mediterranean, and China. The maxima appear to be associated with either concomitant or prior convection in the air masses which carries boundary layer air into the upper troposphere. Previous aircraft measurements of carbon monoxide and ozone over South America are shown to be consistent with this view. In the tropics the three regions of long-term mean rising motion, which form part of the Walker circulation, are associated with elevated carbon monoxide.

  8. Regional studies of potential carbon monoxide sources based on Space Shuttle and aircraft measurements

    NASA Technical Reports Server (NTRS)

    Newell, R. E.; Shipley, S. T.; Connors, V. S.; Reichle, H. G., Jr.

    1988-01-01

    Carbon monoxide measurements made from the space shuttle show maxima over South America, central Africa, the eastern Mediterranean, and China. The maxima appear to be associated with either concomitant or prior convection in the air masses which carries boundary layer air into the upper troposphere. Previous aircraft measurements of carbon monoxide and ozone over South America are shown to be consistent with this view. In the tropics the three regions of long-term mean rising motion, which form part of the Walker circulation, are associated with elevated carbon monoxide.

  9. Ultrasonic techniques for aircraft ice accretion measurement

    NASA Technical Reports Server (NTRS)

    Hansman, R. John, Jr.; Kirby, Mark S.; Lichtenfelts, Fred

    1990-01-01

    Results of tests to measure ice growth in natural (flight) and artificial (icing wind tunnel) icing conditions are presented. Ice thickness is measured using an ultrasonic pulse-echo technique. Two icing regimes, wet and dry ice growth, are identified and the unique ultrasonic signal characteristics associated with these different types of ice growth are described. Ultrasonic measurements of ice growth on cylinders and airfoils exposed to artificial and natural icing conditions are presented. An accuracy of plus or minus 0.5 mm is achieved for ice thickness measurement using the pulse-echo technique. The performance of two-probe type ice detectors is compared to the surface mounted ultrasonic system. The ultrasonically measured ice accretion rates and ice surface condition (wet or dry) are used to compare the heat transfer characteristics for flight and icing wind tunnel environments. In general the heat transfer coefficient is inferred to be higher in the wind tunnel environment, not likely due to higher freestream turbulence levels. Finally, preliminary results of tests to measure ice growth on airfoil using an array of ultrasonic transducers are described. Ice profiles obtained during flight in natural icing conditions are shown and compared with mechanical and stereo image measurements.

  10. Direct strike lightning measurement system. [for aircraft

    NASA Technical Reports Server (NTRS)

    Thomas, M. E.

    1981-01-01

    A research data system developed for in-flight measurement of direct and nearby lightning-strike characteristics is described. The measurement system consists of a wide-band analog recorder which records the continuous lightning scenario and fast sample-rate digital transient recorders with augmented memory capacity for increased time resolution of specific times of interest. Electromagnetic sensors with bandwidths exceeding 100 MHz are used which respond to rates of change of the quantities being measured. Data system immunity from electromagnetic interference is accomplished by the use of a dynamotor for power isolation, shielded system enclosure and fiber-optic data links.

  11. A measurement system for aircraft/weapon electromagnetic compatibility

    SciTech Connect

    Mounteer, T.D.; Scott, L.D.; Stevenson, L.E.

    1991-01-01

    An electromagnetic measurement system (EMMS) was designed and constructed to provide essential data relating to electromagnetic compatibility (EMC) of modern weapons carried on military aircraft. This system measures the equivalent plane wave electric and magnetic fields impinging on a weapon's exterior surface arising from electromagnetic radiators on board host or nearby aircraft. To relate practical sensor responses to specified equivalent plane wave EMC field levels, a modern weapon shape was used as the primary sensor element which responds with a simple dipole antenna response at the lower frequencies and is instrumented with local skin current sensors. At higher frequencies, the locally induced currents can be related to the incident fields by simple scattering theory. Finally, an error analysis that catalogs all measurement path elements was performed to provide an error bound on the equivalent free electric field measurements reported by the EMMS. 6 refs., 9 figs.

  12. Aircraft attitude measurement using a vector magnetometer

    NASA Technical Reports Server (NTRS)

    Peitila, R.; Dunn, W. R., Jr.

    1977-01-01

    The feasibility of a vector magnetometer system was investigated by developing a technique to determine attitude given magnetic field components. Sample calculations are then made using the earth's magnetic field data acquired during actual flight conditions. Results of these calculations are compared graphically with measured attitude data acquired simultaneously with the magnetic data. The role and possible implementation of various reference angles are discussed along with other pertinent considerations. Finally, it is concluded that the earth's magnetic field as measured by modern vector magnetometers can play a significant role in attitude control systems.

  13. MISR Browse Images: Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS)

    Atmospheric Science Data Center

    2016-06-13

    ... Images: Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS)   These MISR Browse images ... the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) field campaign. CLAMS focused on understanding pieces of the ...

  14. Water vapor in the lower stratosphere measured from aircraft flight

    NASA Technical Reports Server (NTRS)

    Hilsenrath, E.; Guenther, B.; Dunn, P.

    1976-01-01

    Water vapor in the lower stratosphere was measured in situ by two aluminum oxide hygrometers mounted on the nose of an RB57 aircraft. Data were taken nearly continuously from January to May 1974 from an altitude of approximately 11 km to 19 km as the aircraft flew between 70 deg N and 50 deg S over the land areas in the Western Hemisphere. Pseudomeridional cross sections of water vapor and temperature are derived from the flight data and show mixing ratios predominantly between 2 and 4 micron gm/gm with an extreme range of 1 to 8 micron gm/gm. Measurement precision is estimated by comparing the simultaneously measured values from the two flight hygrometer systems. Accuracy is estimated to be about + or - 40 percent at 19 km. A height-averaged latitudinal cross section of water vapor shows symmetry of wet and dry zones.

  15. Productivity Measurement in Aircraft Maintenance Organizations

    DTIC Science & Technology

    1990-09-01

    more production, machines, workers, and more capital to finance expansion. All these changes demanded new management practices and larger organizations...Productivity a Labor + Materials + Capital + Energy Management’s task is to bridge the gap from physical measures of operational control to the "big...Material 88.3 97.9 90.3 (3,099) (478) (2,621) Energy 87.8 113.6 77.3 (460) 367 (827) Capital 106.4 100.7 107.7 2,196 261 1,935 Total 95.5 104.2 91.7 $(4,670

  16. Measurement of static pressure on aircraft

    NASA Technical Reports Server (NTRS)

    Gracey, William

    1958-01-01

    Existing data on the errors involved in the measurement of static pressure by means of static-pressure tubes and fuselage vents are presented. The errors associated with the various design features of static-pressure tubes are discussed for the condition of zero angle of attack and for the case where the tube is inclined to flow. Errors which result from variations in the configuration of static-pressure vents are also presented. Errors due to the position of a static-pressure tube in the flow field of the airplane are given for locations ahead of the fuselage nose, ahead of the wing tip, and ahead of the vertical tail fin. The errors of static-pressure vents on the fuselage of an airplane are also presented. Various methods of calibrating static-pressure installations in flight are briefly discussed.

  17. NORTH ELEVATION WITH GRADUATED MEASURING POLE. ABOVEGROUND PORTION IS ON ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    NORTH ELEVATION WITH GRADUATED MEASURING POLE. ABOVE-GROUND PORTION IS ON THE LEFT. VIEW FACING SOUTH - U.S. Naval Base, Pearl Harbor, Ford Island 5-Inch Antiaircraft Battery, Battery Command Center, Ford Island, Pearl City, Honolulu County, HI

  18. EAST ELEVATION WITH GRADUATED MEASURING POLE. VIEW FACING WEST ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    EAST ELEVATION WITH GRADUATED MEASURING POLE. VIEW FACING WEST - U.S. Naval Base, Pearl Harbor, Ford Island 5-Inch Antiaircraft Battery, Battery Command Center, Ford Island, Pearl City, Honolulu County, HI

  19. Long-term greenhouse gas measurements from aircraft

    NASA Astrophysics Data System (ADS)

    Karion, A.; Sweeney, C.; Wolter, S.; Newberger, T.; Chen, H.; Andrews, A.; Kofler, J.; Neff, D.; Tans, P.

    2012-10-01

    In March 2009 the NOAA/ESRL/GMD Carbon Cycle and Greenhouse Gases Group collaborated with the US Coast Guard (USCG) to establish the Alaska Coast Guard (ACG) sampling site, a unique addition to NOAA's atmospheric monitoring network. This collaboration takes advantage of USCG bi-weekly Arctic Domain Awareness (ADA) flights, conducted with Hercules C-130 aircraft from March to November each year. NOAA has installed window-replacement inlet plates on two USCG C-130 aircraft and deploys a pallet with NOAA instrumentation on each ADA flight. Flights typically last 8 h and cover a very large area, traveling from Kodiak, AK in the south up to Barrow, AK in the north, and making altitude profiles near the coast as well as in the interior. NOAA instrumentation on each flight includes: a flask sampling system, a continuous CO2/CH4/CO/H2O analyzer, a continuous ozone analyzer, and an ambient temperature and humidity sensor. GPS time and location from the aircraft's navigation system are also collected. Air samples collected in flight are analyzed at NOAA/ESRL for the major greenhouse gases and a variety of halocarbons and hydrocarbons that influence climate, stratospheric ozone, and air quality. Instruments on this aircraft are designed and deployed to be able to collect air samples and data autonomously, so that NOAA personnel visit the site only for installation at the beginning of each season. We present an assessment of the cavity ring-down spectroscopy (CRDS) CO2/CH4/CO/H2O analyzer performance operating on an aircraft over a three-year period. We describe the overall system for making accurate greenhouse gas measurements using a CRDS analyzer on an aircraft with minimal operator interaction. Short and long-term stability of the CRDS analyzer over a seven-month deployment period is better than 0.15 ppm, 2 ppb, and 5 ppb for CO2, CH4, CO respectively, considering differences of on-board reference tank measurements from a laboratory calibration performed prior to

  20. European measurements of aircraft crew exposure to cosmic radiation.

    PubMed

    Menzel, H G; O'Sullivan, D; Beck, P; Bartlett, D

    2000-11-01

    For more than 5 y, the European Commission has supported research into scientific and technical aspects of cosmic-ray dosimetry at flight altitudes in civil radiation. This has been in response to legislation to regard exposure of aircraft crew as occupational, following the recommendations of the International Commission on Radiological Protection in Publication 60. The response to increased public interest and concern, and in anticipation of European and national current work, within a total of three multi-national, multi-partner research contracts, is based on a comprehensive approach including measurements with dosimetric and spectrometric instruments during flights, at high-mountain altitudes, and in a high-energy radiation reference field at CERN, as well as cosmic-ray transport calculations. The work involves scientists in the fields of neutron physics, cosmic-ray physics, and general dosimetry. A detailed set of measurements has been obtained by employing a wide range of detectors on several routes, both on subsonic and supersonic aircraft. Many of the measurements were made simultaneously by several instruments allowing the intercomparison of results. This paper presents a brief overview of results obtained. It demonstrates that the knowledge about radiation fields and on exposure data has been substantially consolidated and that the available data provide an adequate basis for dose assessments of aircraft crew, which will be legally required in the European Union after 13 May 2000.

  1. Structureborne noise measurements on a small twin-engine aircraft

    NASA Technical Reports Server (NTRS)

    Cole, J. E., III; Martini, K. F.

    1988-01-01

    Structureborne noise measurements performed on a twin-engine aircraft (Beechcraft Baron) are reported. There are two overall objectives of the test program. The first is to obtain data to support the development of analytical models of the wing and fuselage, while the second is to evaluate effects of structural parameters on cabin noise. Measurements performed include structural and acoustic responses to impact excitation, structural and acoustic loss factors, and modal parameters of the wing. Path alterations include added mass to simulate fuel, variations in torque of bolts joining wing and fuselage, and increased acoustic absorption. Conclusions drawn regarding these measurements are presented.

  2. Structureborne noise measurements on a small twin-engine aircraft

    NASA Astrophysics Data System (ADS)

    Cole, J. E., III; Martini, K. F.

    1988-06-01

    Structureborne noise measurements performed on a twin-engine aircraft (Beechcraft Baron) are reported. There are two overall objectives of the test program. The first is to obtain data to support the development of analytical models of the wing and fuselage, while the second is to evaluate effects of structural parameters on cabin noise. Measurements performed include structural and acoustic responses to impact excitation, structural and acoustic loss factors, and modal parameters of the wing. Path alterations include added mass to simulate fuel, variations in torque of bolts joining wing and fuselage, and increased acoustic absorption. Conclusions drawn regarding these measurements are presented.

  3. Accurate aircraft wind measurements using the global positioning system (GPS)

    SciTech Connect

    Dobosy, R.J.; Crawford, T.L., McMillen, R.T., Dumas, E.J.

    1996-11-01

    High accuracy measurements of the spatial distribution of wind speed are required in the study of turbulent exchange between the atmosphere and the earth. The use of a differential global positioning system (GPS) to determine the sensor velocity vector component of wind speed is discussed in this paper. The results of noise and rocking testing are summarized, and fluxes obtained from the GPS-based methods are compared to those measured from systems on towers and airplanes. The GPS-based methods provided usable measurements that compared well with tower and aircraft data at a significantly lower cost. 21 refs., 1 fig., 2 tabs.

  4. Application of laser velocimetry to aircraft wake-vortex measurements

    NASA Technical Reports Server (NTRS)

    Ciffone, D. L.; Orloff, K. L.

    1977-01-01

    The theory and use of a laser velocimeter that makes simultaneous measurements of vertical and longitudinal velocities while rapidly scanning a flow field laterally are described, and its direct application to trailing wake-vortex research is discussed. Pertinent measurements of aircraft wake-vortex velocity distributions obtained in a wind tunnel and water towing tank are presented. The utility of the velocimeter to quantitatively assess differences in wake velocity distributions due to wake dissipating devices and span loading changes on the wake-generating model is also demonstrated.

  5. A measuring stand for a ducted fan aircraft propulsion unit

    NASA Astrophysics Data System (ADS)

    Hlaváček, David

    2014-03-01

    The UL-39 ultra-light aircraft which is being developed by the Department of Aerospace Engineering, Faculty of Mechanical Engineering, Czech Technical University in Prague, is equipped with an unconventional ducted fan propulsion unit. The unit consists of an axial fan driven by a piston engine and placed inside a duct ended with a nozzle. This article describes the arrangement of a modernised measuring stand for this highly specific propulsion unit which will be able to measure the fan pressure ratio and velocity field in front of and behind the fan and its characteristic curve.

  6. A Fiber-Optic Aircraft Lightning Current Measurement Sensor

    NASA Technical Reports Server (NTRS)

    Nguyen, Truong X.; Ely, Jay J.; Szatkowski, George N.

    2013-01-01

    A fiber-optic current sensor based on the Faraday Effect is developed for aircraft installations. It can measure total lightning current amplitudes and waveforms, including continuing current. Additional benefits include being small, lightweight, non-conducting, safe from electromagnetic interference, and free of hysteresis and saturation. The Faraday Effect causes light polarization to rotate in presence of magnetic field in the direction of light propagation. Measuring the total induced light polarization change yields the total current enclosed. The system operates at 1310nm laser wavelength and can measure approximately 300 A - 300 kA, a 60 dB range. A reflective polarimetric scheme is used, where the light polarization change is measured after a round-trip propagation through the fiber. A two-detector setup measures the two orthogonal polarizations for noise subtraction and improved dynamic range. The current response curve is non-linear and requires a simple spline-fit correction. Effects of high current were achieved in laboratory using combinations of multiple fiber and wire loops. Good result comparisons against reference sensors were achieved up to 300 kA. Accurate measurements on a simulated aircraft fuselage and an internal structure illustrate capabilities that maybe difficult with traditional sensors. Also tested at a commercial lightning test facility from 20 kA to 200 kA, accuracy within 3-10% was achieved even with non-optimum setups.

  7. Fiber-Optic Sensor for Aircraft Lightning Current Measurement

    NASA Technical Reports Server (NTRS)

    Nguyen, Truong X.; Ely, Jay J.; Szatkowski, George G.; Mata, Carlos T.; Mata,Angel G.; Snyder, Gary P.

    2012-01-01

    An electric current sensor based on Faraday rotation effect in optical fiber was developed for measuring aircraft lightning current. Compared to traditional sensors, the design has many advantages including the ability to measure total current and to conform to structure geometries. The sensor is also small, light weight, non-conducting, safe from interference, and free of hysteresis and saturation. Potential applications include characterization of lightning current waveforms, parameters and paths, and providing environmental data for aircraft certifications. In an optical fiber as the sensing medium, light polarization rotates when exposed to a magnetic field in the direction of light propagation. By forming closed fiber loops around a conductor and applying Ampere s law, measuring the total light rotation yields the enclosed current. A reflective polarimetric scheme is used, where polarization change is measured after the polarized light travels round-trip through the sensing fiber. The sensor system was evaluated measuring rocket-triggered lightning over the 2011 summer. Early results compared very well against a reference current shunt resistor, demonstrating the sensor's accuracy and feasibility in a lightning environment. While later comparisons show gradually increasing amplitude deviations for an undetermined cause, the overall waveforms still compared very well.

  8. Fiber-Optic Sensor for Aircraft Lightning Current Measurement

    NASA Technical Reports Server (NTRS)

    Nguyen, Truong X.; Ely, Jay J.; Szatkowski, George G.; Mata, Carlos T.; Mata, Angel G.; Snyder, Gary P.

    2012-01-01

    An electric current sensor based on Faraday rotation effect in optical fiber was developed for measuring aircraft lightning current. Compared to traditional sensors, the design has many advantages including the ability to measure total current and to conform to structure geometries. The sensor is also small, light weight, non-conducting, safe from interference, and free of hysteresis and saturation. Potential applications include characterization of lightning current waveforms, parameters and paths, and providing environmental data for aircraft certifications. In an optical fiber as the sensing medium, light polarization rotates when exposed to a magnetic field in the direction of light propagation. By forming closed fiber loops around a conductor and applying Ampere s law, measuring the total light rotation yields the enclosed current. A reflective polarimetric scheme is used, where polarization change is measured after the polarized light travels round-trip through the sensing fiber. The sensor system was evaluated measuring rocket-triggered lightning over the 2011 summer. Early results compared very well against a reference current shunt resistor, demonstrating the sensor s accuracy and feasibility in a lightning environment. While later comparisons show gradually increasing amplitude deviations for an undetermined cause, the overall waveforms still compared very well.

  9. The Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) Experiment

    NASA Technical Reports Server (NTRS)

    Smith, William L., Jr.; Charlock, Thomas; Wielicki, Bruce; Kahn, Ralph; Martins, J. Vanderlei; Gatebe, Charles; Hobbs, Peter V.; Purgold, G. Carl; Redemann, Jens; Remer, Lorraine

    2004-01-01

    NASA has developed an Earth Observing System (EOS) consisting of a series of satellites designed to study global change from space. The EOS flagship is the EOS TERRA satellite, launched in December 1999, equipped with five unique sensors to monitor and study the Earth s heat budget and many of the key controlling variables governing the Earth's climate system. CLAMS, the Chesapeake Lighthouse and Aircraft Measurements for Satellites field campaign was conducted from NASA Wallops Flight Facility and successfully executed over the middle Atlantic eastern seaboard from July 10 August 2, 2001. CLAMS is primarily a shortwave closure experiment designed to validate and improve EOS TERRA satellite data products being derived from three sensors: CERES (Clouds and Earth's Radiant Energy System), MISR (Multi-angle Imaging Spectro-Radiometer) and MODIS (MODerate Resolution Imaging Spectroradiometer). CLAMS is jointly sponsored by the CERES, MISR and MODIS instrument teams and the NASA GEWEX Global Aerosol Climatology Project (GACP). CLAMS primary objectives are to validate satellite-based retrievals of aerosol properties and vertical profiles of radiative flux, temperature and water vapor. Central to CLAMS measurement strategy is the Chesapeake Lighthouse, a stable sea platform located in the Atlantic Ocean, 13 miles east of Virginia Beach near the mouth of the Chesapeake Bay and the site of an ongoing CERES Ocean Validation Experiment (COVE). Six research aircraft were deployed to make detailed measurements of the atmosphere and ocean surface in the vicinity of COVE, over the surrounding ocean, over nearby NOAA buoys and over a few land sites. The measurements are used to validate and provide ground truth for simultaneous products being derived from TERRA data, a key step toward an improved understanding and ability to predict changes in the Earth's climate. One of the two CERES instruments on-board TERRA was programmed for Rotating Azimuth Plane Scans (RAPS) during CLAMS

  10. Wind Tunnel Measurements and Calculations of Aerodynamic Interactions Between Tiltrotor Aircraft

    NASA Technical Reports Server (NTRS)

    Johnson, Wayne; Yamauchi, Gloria K.; Derby, Michael R.; Wadcock, Alan J.

    2002-01-01

    Wind tunnel measurements and calculations of the aerodynamic interactions between two tiltrotor aircraft in helicopter mode are presented. The measured results include the roll moment and thrust change on the downwind aircraft, as a function of the upwind aircraft position (longitudinal, lateral, and vertical). Magnitudes and locations of the largest interactions are identified. The calculated interactions generally match the measurements, with discrepancies attributed to the unsteadiness of the wake and aerodynamic forces on the airframe. To interpret the interactions in terms of control and power changes on the aircraft, additional calculations are presented for trimmed aircraft with gimballed rotors.

  11. Aircraft Loss-of-Control Accident Prevention: Switching Control of the GTM Aircraft with Elevator Jam Failures

    NASA Technical Reports Server (NTRS)

    Chang, Bor-Chin; Kwatny, Harry G.; Belcastro, Christine; Belcastro, Celeste

    2008-01-01

    Switching control, servomechanism, and H2 control theory are used to provide a practical and easy-to-implement solution for the actuator jam problem. A jammed actuator not only causes a reduction of control authority, but also creates a persistent disturbance with uncertain amplitude. The longitudinal dynamics model of the NASA GTM UAV is employed to demonstrate that a single fixed reconfigured controller design based on the proposed approach is capable of accommodating an elevator jam failure with arbitrary jam position as long as the thrust control has enough control authority. This paper is a first step towards solving a more comprehensive in-flight loss-of-control accident prevention problem that involves multiple actuator failures, structure damages, unanticipated faults, and nonlinear upset regime recovery, etc.

  12. Aircraft

    DTIC Science & Technology

    2003-01-01

    national power. But with the recent events such as the war with Iraq, the Severe Acute Respiratory Syndrome (SARS) outbreak, some major carriers... TITLE AND SUBTITLE 2003 Industry Studies: Aircraft 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER

  13. Unmanned Aircraft Systems for Rapid Near Surface Geophysical Measurements

    NASA Astrophysics Data System (ADS)

    Stoll, J. B.

    2013-08-01

    This paper looks at some of the unmanned aircraft systems (UAS) options and deals with a magnetometer sensor system which might be of interest in conducting rapid near surface geophysical measurements. Few of the traditional airborne geophysical sensors are now capable of being miniaturized to sizes and payload within mini UAS limits (e.g. airborne magnetics, gamma ray spectrometer). Here the deployment of a fluxgate magnetometer mounted on an UAS is presented demonstrating its capability of detecting metallic materials that are buried in the soil. The effectiveness in finding ferrous objects (e.g. UXO, landslides) is demonstrated in two case studies.

  14. The surface elevation table: marker horizon method for measuring wetland accretion and elevation dynamics

    USGS Publications Warehouse

    Callaway, John C.; Cahoon, Donald R.; Lynch, James C.

    2014-01-01

    Tidal wetlands are highly sensitive to processes that affect their elevation relative to sea level. The surface elevation table–marker horizon (SET–MH) method has been used to successfully measure these processes, including sediment accretion, changes in relative elevation, and shallow soil processes (subsidence and expansion due to root production). The SET–MH method is capable of measuring changes at very high resolution (±millimeters) and has been used worldwide both in natural wetlands and under experimental conditions. Marker horizons are typically deployed using feldspar over 50- by 50-cm plots, with replicate plots at each sampling location. Plots are sampled using a liquid N2 cryocorer that freezes a small sample, allowing the handling and measurement of soft and easily compressed soils with minimal compaction. The SET instrument is a portable device that is attached to a permanent benchmark to make high-precision measurements of wetland surface elevation. The SET instrument has evolved substantially in recent decades, and the current rod SET (RSET) is widely used. For the RSET, a 15-mm-diameter stainless steel rod is pounded into the ground until substantial resistance is achieved to establish a benchmark. The SET instrument is attached to the benchmark and leveled such that it reoccupies the same reference plane in space, and pins lowered from the instrument repeatedly measure the same point on the soil surface. Changes in the height of the lowered pins reflect changes in the soil surface. Permanent or temporary platforms provide access to SET and MH locations without disturbing the wetland surface.

  15. A Comprehensive Program for Measurement of Military Aircraft Emissions

    SciTech Connect

    Cheng, Mengdawn

    2009-11-01

    Emissions of gases and particulate matter by military aircraft were characterized inplume by 'extractive' and 'optical remote-sensing (ORS)' technologies. Non-volatile particle size distribution, number and mass concentrations were measured with good precision and reproducibly. Time-integrated particulate filter samples were collected and analyzed for smoke number, elemental composition, carbon contents, and sulfate. Observed at EEP the geometric mean diameter (as measured by the mobility diameter) generally increased as the engine power setting increased, which is consistent with downstream observations. The modal diameters at the downstream locations are larger than that at EEP at the same engine power level. The results indicate that engine particles were processed by condensation, for example, leading to particle growth in-plume. Elemental analysis indicated little metals were present in the exhaust, while most of the exhaust materials in the particulate phase were carbon and sulfate (in the JP-8 fuel). CO, CO{sub 2}, NO, NO{sub 2}, SO{sub 2}, HCHO, ethylene, acetylene, propylene, and alkanes were measured. The last five species were most noticeable under engine idle condition. The levels of hydrocarbons emitted at high engine power level were generally below the detection limits. ORS techniques yielded real-time gaseous measurement, but the same techniques could not be extended directly to ultrafine particles found in all engine exhausts. The results validated sampling methodology and measurement techniques used for non-volatile particulate aircraft emissions, which also highlighted the needs for further research on sampling and measurement for volatile particulate matter and semi-volatile species in the engine exhaust especially at the low engine power setting.

  16. A method for measuring aircraft height and velocity using dual television cameras

    NASA Technical Reports Server (NTRS)

    Young, W. R.

    1977-01-01

    A unique electronic optical technique, consisting of two closed circuit television cameras and timing electronics, was devised to measure an aircraft's horizontal velocity and height above ground without the need for airborne cooperative devices. The system is intended to be used where the aircraft has a predictable flight path and a height of less than 660 meters (2,000 feet) at or near the end of an air terminal runway, but is suitable for greater aircraft altitudes whenever the aircraft remains visible. Two television cameras, pointed at zenith, are placed in line with the expected path of travel of the aircraft. Velocity is determined by measuring the time it takes the aircraft to travel the measured distance between cameras. Height is determined by correlating this speed with the time required to cross the field of view of either camera. Preliminary tests with a breadboard version of the system and a small model aircraft indicate the technique is feasible.

  17. High-precision measurements of wetland sediment elevation. II The rod surface elevation table

    USGS Publications Warehouse

    Cahoon, D.R.; Lynch, J.C.; Perez, B.C.; Segura, B.; Holland, R.D.; Stelly, C.; Stephenson, G.; Hensel, P.

    2002-01-01

    A new high-precision device for measuring sediment elevation in emergent and shallow water wetland systems is described. The rod surface-elevation table (RSET) is a balanced, lightweight mechanical leveling device that attaches to both shallow ( 1 m in order to be stable. The pipe is driven to refusal but typically to a depth shallower than the rod bench mark because of greater surface resistance of the pipe. Thus, the RSET makes it possible to partition change in sediment elevation over shallower (e.g., the root zone) and deeper depths of the sediment profile than is possible with the SET. The confidence intervals for the height of an individual pin measured by two different operators with the RSET under laboratory conditions were A? 1.0 and A? 1.5 mm. Under field conditions, confidence intervals for the measured height of an individual pin ranged from A? 1.3 mm in a mangrove forest up to A? 4.3 mm in a salt marsh.

  18. WEST ELEVATION WITH GRADUATED MEASURING POLE. NOTE THE CIRCULAR OPENINGS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    WEST ELEVATION WITH GRADUATED MEASURING POLE. NOTE THE CIRCULAR OPENINGS INTO THE UNDERGROUND PORTION OF THE STRUCTURE. VIEW FACING EAST - U.S. Naval Base, Pearl Harbor, Ford Island 5-Inch Antiaircraft Battery, Battery Command Center, Ford Island, Pearl City, Honolulu County, HI

  19. SOUTH ELEVATION OF BATTERY COMMAND CENTER WITH GRADUATED MEASURING POLE. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    SOUTH ELEVATION OF BATTERY COMMAND CENTER WITH GRADUATED MEASURING POLE. THE ENTRY STAIRWAY IS IN THE FOREGROUND. THE ABOVE-GROUND SECTION OF THE STRUCTURE IS ON THE RIGHT, UNDERGROUND PORTION ON THE LEFT. VIEW FACING NORTH - U.S. Naval Base, Pearl Harbor, Ford Island 5-Inch Antiaircraft Battery, Battery Command Center, Ford Island, Pearl City, Honolulu County, HI

  20. Analysis of aircraft microwave measurements of the ocean surface

    NASA Technical Reports Server (NTRS)

    Willand, J. H.; Fowler, M. G.; Reifenstein, E. C., III; Chang, D. T.

    1973-01-01

    A data system was developed to process, from calibrated brightness temperature to computation of estimated parameters, the microwave measurements obtained by the NASA CV-990 aircraft during the 1972 Meteorological Expedition. A primary objective of the study was the implementation of an integrated software system at the computing facility of NASA/GSFC, and its application to the 1972 data. A single test case involving measurements away from and over a heavy rain cell was chosen to examine the effect of clouds upon the ability to infer ocean surface parameters. The results indicate substantial agreement with those of the theoretical study; namely, that the values obtained for the surface properties are consistent with available ground-truth information, and are reproducible except within the heaviest portions of the rain cell, at which nonlinear (or saturation) effects become apparent. Finally, it is seen that uncorrected instrumental effects introduce systematic errors which may limit the accuracy of the method.

  1. Aircraft measurements of aerosols in the upper troposphere at midlatitudes

    NASA Technical Reports Server (NTRS)

    Morita, Y.; Takagi, M.; Kondo, Y.

    1985-01-01

    Aircraft measurements of aerosols were made during the years 1982 to 1984 in the upper troposphere. In some cases, the influence of the local atmospheric pollution originating from the land surface was observed. The background concentration of the Mie particle was about 0.1/cu. cm. at an altitude of 6 to 8 km. An air mass of stratospheric origin was observed over the Japan sea in the winters of 1983 and 1984. The Mie particle concentration increased and the count ratio of two size ranges was found to be a large value in 1983, the value decreased to that of a background level in the stratosphere in 1984. The volcanic eruption of Mt. El Chichon seems to be responsible for the large aerosol count ratio of the measurements of 1983.

  2. IMPROVEMENTS ON THE RONNE SYSTEM OF CLOUD MEASUREMENTS FROM AIRCRAFT MOTION PICTURE FILMS,

    DTIC Science & Technology

    AIRCRAFT, MOTION PICTURE CAMERAS, MOTION PICTURE FILM , COMPUTER PROGRAMMING, METEOROLOGICAL INSTRUMENTS.... MOTION PICTURE PHOTOGRAPHY, AERIAL PHOTOGRAPHY, AERIAL PHOTOGRAPHY, CLOUD HEIGHT INDICATORS, CLOUDS, HEIGHT FINDING, DISTANCE MEASURING EQUIPMENT

  3. Long-term greenhouse gas measurements from aircraft

    NASA Astrophysics Data System (ADS)

    Karion, A.; Sweeney, C.; Wolter, S.; Newberger, T.; Chen, H.; Andrews, A.; Kofler, J.; Neff, D.; Tans, P.

    2013-03-01

    In March 2009 the NOAA/ESRL/GMD Carbon Cycle and Greenhouse Gases Group collaborated with the US Coast Guard (USCG) to establish the Alaska Coast Guard (ACG) sampling site, a unique addition to NOAA's atmospheric monitoring network. This collaboration takes advantage of USCG bi-weekly Arctic Domain Awareness (ADA) flights, conducted with Hercules C-130 aircraft from March to November each year. Flights typically last 8 h and cover a large area, traveling from Kodiak up to Barrow, Alaska, with altitude profiles near the coast and in the interior. NOAA instrumentation on each flight includes a flask sampling system, a continuous cavity ring-down spectroscopy (CRDS) carbon dioxide (CO2)/methane (CH4)/carbon monoxide (CO)/water vapor (H2O) analyzer, a continuous ozone analyzer, and an ambient temperature and humidity sensor. Air samples collected in flight are analyzed at NOAA/ESRL for the major greenhouse gases and a variety of halocarbons and hydrocarbons that influence climate, stratospheric ozone, and air quality. We describe the overall system for making accurate greenhouse gas measurements using a CRDS analyzer on an aircraft with minimal operator interaction and present an assessment of analyzer performance over a three-year period. Overall analytical uncertainty of CRDS measurements in 2011 is estimated to be 0.15 ppm, 1.4 ppb, and 5 ppb for CO2, CH4, and CO, respectively, considering short-term precision, calibration uncertainties, and water vapor correction uncertainty. The stability of the CRDS analyzer over a seven-month deployment period is better than 0.15 ppm, 2 ppb, and 4 ppb for CO2, CH4, and CO, respectively, based on differences of on-board reference tank measurements from a laboratory calibration performed prior to deployment. This stability is not affected by variation in pressure or temperature during flight. We conclude that the uncertainty reported for our measurements would not be significantly affected if the measurements were made without in

  4. Coupled Gravity and Elevation Measurement of Ice Sheet Mass Change

    NASA Technical Reports Server (NTRS)

    Jezek, K. C.; Baumgartner, F.

    2005-01-01

    During June 2003, we measured surface gravity at six locations about a glaciological measurement site located on the South-central Greenland Ice. We operated a GPS unit for 90 minutes at each site -the unit was operated simultaneously with a base station unit in Sondrestrom Fjord so as to enable differential, post-processing of the data. We installed an aluminum, accumulation-rate-pole at each site. The base section of the pole also served as the mount for the GPS antenna. Two gravimeters were used simultaneously at each site. Measurements were repeated at each site with at time lapse of at least 50 minutes. We measured snow physical properties in two shallow pits The same measurement sites were occupied in 1981 and all were part of a hexagonal network of geodetic and glaciological measurements established by The Ohio State University in 1980. Additional gravity observations were acquired at three of the sites in 1993 and 1995. Gravity data were collected in conjunction with Doppler satellite measurements of position and elevation in 1981 and global positioning system measurements subsequently. The use of satellite navigation techniques permitted reoccupation of the same sites in each year to within a few 10 s of meters or better. After detrending the gravity data, making adjustments for tides and removing the residual effects of local spatial gradients in gravity, we observe an average secular decrease in gravity of about 0.01 milligal/year, but with tenths of milligal variations about the mean trend. The trend is consistent with a nearly linear increase in surface elevation of between 7 to 10 c d y r (depending on location) as measured by repeated airborne laser altimeter, surface Doppler satellite and GPS elevation measurements. Differences between the residual gravity anomalies after free air correction may be attributable to local mass changes. This project is a collaboration between the Byrd Polar Research Center of the Ohio State University and the Arctic

  5. Wide field of view laser beacon system for three dimensional aircraft range measurements

    NASA Technical Reports Server (NTRS)

    Wong, E. Y.

    1982-01-01

    A system that measures accurately the distance from an aircraft to a helicoper for rotor noise flight testing was developed. The system measures the range and angles between two aircraft using laser optics. This system can be applied in collision avoidance, robotics and other measurement critical tasks.

  6. Surface roughness measurement on a wing aircraft by speckle correlation.

    PubMed

    Salazar, Félix; Barrientos, Alberto

    2013-09-05

    The study of the damage of aeronautical materials is important because it may change the microscopic surface structure profiles. The modification of geometrical surface properties can cause small instabilities and then a displacement of the boundary layer. One of the irregularities we can often find is surface roughness. Due to an increase of roughness and other effects, there may be extra momentum losses in the boundary layer and a modification in the parasite drag. In this paper we present a speckle method for measuring the surface roughness on an actual unmanned aircraft wing. The results show an inhomogeneous roughness distribution on the wing, as expected according to the anisotropic influence of the winds over the entire wing geometry. A calculation of the uncertainty of the technique is given.

  7. Aircraft measurements of microwave emission from Arctic Sea ice

    USGS Publications Warehouse

    Wilheit, T.; Nordberg, W.; Blinn, J.; Campbell, W.; Edgerton, A.

    1971-01-01

    Measurements of the microwave emission from Arctic Sea ice were made with aircraft at 8 wavelengths ranging from 0.510 to 2.81 cm. The expected contrast in emissivities between ice and water was observed at all wavelengths. Distributions of sea ice and open water were mapped from altitudes up to 11 km in the presence of dense cloud cover. Different forms of ice also exhibited strong contrasts in emissivity. Emissivity differences of up to 0.2 were observed between two types of ice at the 0.811-cm wavelength. The higher emissivity ice type is tentatively identified as having been formed more recently than the lower emissivity ice. ?? 1971.

  8. Surface Roughness Measurement on a Wing Aircraft by Speckle Correlation

    PubMed Central

    Salazar, Félix; Barrientos, Alberto

    2013-01-01

    The study of the damage of aeronautical materials is important because it may change the microscopic surface structure profiles. The modification of geometrical surface properties can cause small instabilities and then a displacement of the boundary layer. One of the irregularities we can often find is surface roughness. Due to an increase of roughness and other effects, there may be extra momentum losses in the boundary layer and a modification in the parasite drag. In this paper we present a speckle method for measuring the surface roughness on an actual unmanned aircraft wing. The results show an inhomogeneous roughness distribution on the wing, as expected according to the anisotropic influence of the winds over the entire wing geometry. A calculation of the uncertainty of the technique is given. PMID:24013488

  9. Airdata calibration of a high-performance aircraft for measuring atmospheric wind profiles

    NASA Technical Reports Server (NTRS)

    Haering, Edward A., Jr.

    1990-01-01

    The research airdata system of an instrumented F-104 aircraft has been calibrated to measure winds aloft in support of the Space Shuttle wind measurement investigation. The F-104 aircraft was equipped with a research pitot-static noseboom with integral angle-of-attack and flank angle-of-attack vanes and a ring-laser-gyro inertial reference unit. The F-104 aircraft and instrumentation configuration, flight test maneuvers, data corrections, calibration techniques, and resulting calibrations and data repeatability are presented. Recommendations for future airdata systems on aircraft used to measure winds aloft are also given.

  10. MARS: A New Retrieval Scheme for Aircraft Remote Sensing Measurements

    NASA Astrophysics Data System (ADS)

    Illingworth, Samuel; Allen, Grant; Gallagher, Martin; O'Shea, Sebastian; Newman, Stuart; Vance, Alan; Remedios, John; Moore, David

    2013-04-01

    The importance of aircraft in-situ measurements of GreenHouse Gases (GHG) and trace gases is well understood, providing not only spatially resolved and accurate concentration data for these gases, but also essential validation for many other types of measurement, the most common being that from ground-based and satellite remote sensing instrumentation. The role of airborne remote sensing instruments is equally important in building up an accurate understanding of the composition of the atmosphere, providing far greater spatial coverage than their ground-based equivalents, whilst in the thermal infrared, the opportunity to fly at relatively low altitudes allows for a greater sensitivity towards the surface than that provided by any current satellite measurements. The UK Met Office Airborne Research Interferometer Evaluation System (ARIES) is a Fourier transform spectrometer that is mounted on the NERC Facility for Airborne Atmospheric Measurements (FAAM) aircraft, and which measures incoming radiation over a large wavenumber range (550-3000 cm-1), at high spectral resolution (~0.7 cm-1 unapodised). This level of precision, combined with a low NEDT (0.2 K for 1-minute averaged spectra) allows for the detection of a wide variety of important GHG and trace gases, the concentrations of which can be derived from the measured spectra by use of retrieval theory. This work presents a new Optimal Estimation Method (OEM) retrieval of GHG and trace gas vertically resolved profiles in the mid-troposphere and planetary boundary layer, from observations of the ARIES instrument. The Manchester ARIES Retrieval Scheme (MARS) utilizes a large subset of high-accuracy and high-precision auxiliary datasets to produce a well-characterized retrieval product. First retrieval results, as well as a validation of these results with in-situ measurements are to be presented, with error characterization suggesting that the retrieval bias is of the order of 1-2%. As well as presenting the results

  11. Full Flight Envelope Direct Thrust Measurement on a Supersonic Aircraft

    NASA Technical Reports Server (NTRS)

    Conners, Timothy R.; Sims, Robert L.

    1998-01-01

    Direct thrust measurement using strain gages offers advantages over analytically-based thrust calculation methods. For flight test applications, the direct measurement method typically uses a simpler sensor arrangement and minimal data processing compared to analytical techniques, which normally require costly engine modeling and multisensor arrangements throughout the engine. Conversely, direct thrust measurement has historically produced less than desirable accuracy because of difficulty in mounting and calibrating the strain gages and the inability to account for secondary forces that influence the thrust reading at the engine mounts. Consequently, the strain-gage technique has normally been used for simple engine arrangements and primarily in the subsonic speed range. This paper presents the results of a strain gage-based direct thrust-measurement technique developed by the NASA Dryden Flight Research Center and successfully applied to the full flight envelope of an F-15 aircraft powered by two F100-PW-229 turbofan engines. Measurements have been obtained at quasi-steady-state operating conditions at maximum non-augmented and maximum augmented power throughout the altitude range of the vehicle and to a maximum speed of Mach 2.0 and are compared against results from two analytically-based thrust calculation methods. The strain-gage installation and calibration processes are also described.

  12. The measurement of aircraft performance and stability and control after flight through natural icing conditions

    NASA Technical Reports Server (NTRS)

    Ranaudo, R. J.; Mikkelsen, K. L.; Mcknight, R. C.; Ide, R. F.; Reehorst, A. L.; Jordan, J. L.; Schinstock, W. C.; Platz, S. J.

    1986-01-01

    The effects of airframe icing on the performance and stability and control of a twin-engine commuter-class aircraft were measured by the NASA Lewis Research Center. This work consisted of clear air tests with artificial ice shapes attached to the horizontal tail, and natural icing flight tests in measured icing clouds. The clear air tests employed static longitudinal flight test methods to determine degradation in stability margins for four simulated ice shapes. The natural icing flight tests employed a data acquisition system, which was provided under contract to NASA by Kohlman Systems Research Incorporated. This system used a performance modeling method and modified maximum likelihood estimation (MMLE) technique to determine aircraft performance degradation and stability and control. Flight test results with artificial ice shapes showed that longitudinal, stick-fixed, static margins are reduced on the order of 5 percent with flaps up. Natural icing tests with the KSR system corroborated these results and showed degradation in the elevator control derivatives on the order of 8 to 16 percent depending on wing flap configuration. Performance analyses showed the individual contributions of major airframe components to the overall degration in lift and drag.

  13. Experimental Study of the Stability of Aircraft Fuels at Elevated Temperatures

    NASA Technical Reports Server (NTRS)

    Vranos, A.; Marteney, P. J.

    1980-01-01

    An experimental study of fuel stability was conducted in an apparatus which simulated an aircraft gas turbine fuel system. Two fuels were tested: Jet A and Number 2 Home Heating oil. Jet A is an aircraft gas turbine fuel currently in wide use. No. 2HH was selected to represent the properties of future turbine fuels, particularly experimental Reference Broad Specification, which, under NASA sponsorship, was considered as a possible next-generation fuel. Tests were conducted with varying fuel flow rates, delivery pressures and fuel pretreatments (including preheating and deoxygenation). Simulator wall temperatures were varied between 422K and 672K at fuel flows of 0.022 to 0.22 Kg/sec. Coking rate was determined at four equally-spaced locations along the length of the simulator. Fuel samples were collected for infrared analysis. The dependence of coking rate in Jet A may be correlated with surface temperature via an activation energy of 9 to 10 kcal/mole, although the results indicate that both bulk fluid and surface temperature affect the rate of decomposition. As a consequence, flow rate, which controls bulk temperature, must also be considered. Taken together, these results suggest that the decomposition reactions are initiated on the surface and continue in the bulk fluid. The coking rate data for No. 2 HH oil are very highly temperature dependent above approximately 533K. This suggests that bulk phase reactions can become controlling in the formation of coke.

  14. Real-time measurements of jet aircraft engine exhaust.

    PubMed

    Rogers, Fred; Arnott, Pat; Zielinska, Barbara; Sagebiel, John; Kelly, Kerry E; Wagner, David; Lighty, JoAnn S; Sarofim, Adel F

    2005-05-01

    Particulate-phase exhaust properties from two different types of ground-based jet aircraft engines--high-thrust and turboshaft--were studied with real-time instruments on a portable pallet and additional time-integrated sampling devices. The real-time instruments successfully characterized rapidly changing particulate mass, light absorption, and polycyclic aromatic hydrocarbon (PAH) content. The integrated measurements included particulate-size distributions, PAH, and carbon concentrations for an entire test run (i.e., "run-integrated" measurements). In all cases, the particle-size distributions showed single modes peaking at 20-40nm diameter. Measurements of exhaust from high-thrust F404 engines showed relatively low-light absorption compared with exhaust from a turboshaft engine. Particulate-phase PAH measurements generally varied in phase with both net particulate mass and with light-absorbing particulate concentrations. Unexplained response behavior sometimes occurred with the real-time PAH analyzer, although on average the real-time and integrated PAH methods agreed within the same order of magnitude found in earlier investigations.

  15. Acoustic measurements of F-16 aircraft operating in hush house, NSN 4920-02-070-2721

    NASA Astrophysics Data System (ADS)

    Miller, V. R.; Plzak, G. A.; Chinn, J. M.

    1981-09-01

    The purpose of this test program was to measure the acoustic environment in the hush house facility located at Kelly Air Force Base, Texas, during operation of the F-16 aircraft to ensure that aircraft structural acoustic design limits were not exceeded. The acoustic measurements showed that no sonic fatigue problems are anticipated with the F-16 aircraft aft fuselage structure during operation in the hush house. The measured acoustic levels were less than those measured in an F-16 aircraft water cooled hush house at Hill AFB, but were increased over that measured during ground run up. It was recommended that the acoustic loads measured in this program should be specified in the structural design criteria for aircraft which will be subjected to hush house operation or defining requirements for associated equipment.

  16. Radiation measurements over a snowfield at an elevated site

    NASA Technical Reports Server (NTRS)

    Korff, H. C.; Gailiun, J. J.; Vonderhaar, T. H.

    1974-01-01

    The components of short wave radiation were measured over a snowfield in a valley of the Rocky Mountains at a height of 2700 m above sea level. Global and reflected radiation were obtained by a set of Eppley pyranometers. In addition, the direct solar radiation and the turbidity of the atmosphere were derived from pyrheliometric data on cloud-free days. Emphasis was given to the reflectance of the snowfield in relation to the position of the sun, especially at low elevation angles. These reflectance values were measured for cloudless as well as for cloudy days and compared with already published values for arctic and antarctic conditions.

  17. Review of subjective measures of human response to aircraft noise

    NASA Technical Reports Server (NTRS)

    Cawthorn, J. M.; Mayes, W. H.

    1976-01-01

    The development of aircraft noise rating scales and indexes is reviewed up to the present time. Single event scales, multiple event indexes, and their interrelation with each other, are considered. Research requirements for further refinement and development of aircraft noise rating quantification factors are discussed.

  18. Wind Tunnel Measurements and Calculations of Aerodynamic Interactions Between Tiltrotor Aircraft

    DTIC Science & Technology

    2003-01-01

    the wake of the upwind aircraft. The aircraft were in helicopter configuration ( nacelle angle 90 deg), with the rotor shafts vertical and the wing at...indicating downward convection of the wake (so the upwind aircraft was higher at the maximum interaction). Similar wake behavior was observed in lidar ...Libby, J.; "Wake Vortex Measurements of the XV-15 Tiltrotor Using a Mobile Ground-Based Lidar System." AHS International 57th Annual Forum Proceedings

  19. Experimental flight test vibration measurements and nondestructive inspection on a USCG HC-130H aircraft

    SciTech Connect

    Moore, D.G.; Jones, C.R.; Mihelic, J.E.; Barnes, J.D.

    1998-08-01

    This paper presents results of experimental flight test vibration measurements and structural inspections performed by the Federal Aviation Administration`s Airworthiness Assurance NDI Validation Center (AANC) at Sandia National Laboratories and the US Coast Guard Aircraft Repair and Supply Center (ARSC). Structural and aerodynamic changes induced by mounting a Forward Looking Infrared (FLIR) system on a USCG HC-130H aircraft are described. The FLIR adversely affected the air flow characteristics and structural vibration on the external skin of the aircraft`s right main wheel well fairing. Upon initial discovery of skin cracking and visual observation of skin vibration in flight by the FLIR, a baseline flight without the FLIR was conducted and compared to other measurements with the FLIR installed. Nondestructive inspection procedures were developed to detect cracks in the skin and supporting structural elements and document the initial structural condition of the aircraft. Inspection results and flight test vibration data revealed that the FLIR created higher than expected flight loading and was the possible source of the skin cracking. The Coast Guard performed significant structural repair and enhancement on this aircraft, and additional in-flight vibration measurements were collected on the strengthened area both with and without the FLIR installed. After three months of further operational FLIR usage, the new aircraft skin with the enhanced structural modification was reinspected and found to be free of flaws. Additional US Coast Guard HC-130H aircraft are now being similarly modified to accommodate this FLIR system. Measurements of in-flight vibration levels with and without the FLIR installed, and both before and after the structural enhancement and repair were conducted on the skin and supporting structure in the aircraft`s right main wheel fairing. Inspection results and techniques developed to verify the aircraft`s structural integrity are discussed.

  20. Perspectives on African Ozone from Sondes, Dobson and Aircraft Measurements

    NASA Technical Reports Server (NTRS)

    Thompson, A. M.; Witte, J. C.; Chatfield, R. B.; Diab, R. D.; Thouret, V.; Sauvage, B.

    2004-01-01

    We have been studying variability in ozone over Africa using data from ozonesondes (vertical profiles from surface to stratosphere), aircraft (the MOZAIC dataset with cruise altitude and landing/takeoff profiles) and the ground (Dobson spectrophotometer total ozone column measurement). The following may give context for ozone investigations during AMMA: 1. Total ozone measurements since 1989 show considerable variability in mean value among the African stations in Algeria, Kenya, Egypt, South Africa, as well as in seasonal cycles and year-to-year. Trends are not evident. 2. The impacts of convection, stratospheric injection, biomass burning and lightning appear in ozone sounding profile data. Time-series analysis and case studies point to periodic influences of long-range interactions with the Atlantic ("ozone paradox," wave-one") and Indian Oceans. 3. Tropospheric ozone variations, observed in tropospheric profiles and integrated column amount, follow general seasonal patterns but short- term variability is so strong that simple averages are inadequate for describing "climatology" and statistical classification approaches may be required.

  1. In-flight and simulated aircraft fuel temperature measurements

    NASA Technical Reports Server (NTRS)

    Svehla, Roger A.

    1990-01-01

    Fuel tank measurements from ten flights of an L1011 commercial aircraft are reported for the first time. The flights were conducted from 1981 to 1983. A thermocouple rake was installed in an inboard wing tank and another in an outboard tank. During the test periods of either 2 or 5 hr, at altitudes of 10,700 m (35,000 ft) or higher, either the inboard or the outboard tank remained full. Fuel temperature profiles generally developed in the expected manner. The bulk fuel was mixed by natural convection to a nearly uniform temperature, especially in the outboard tank, and a gradient existed at the bottom conduction zone. The data indicated that when full, the upper surface of the inboard tank was wetted and the outboard tank was unwetted. Companion NASA Lewis Research Center tests were conducted in a 0.20 cubic meter (52 gal) tank simulator of the outboard tank, chilled on the top and bottom, and insulated on the sides. Even though the simulator tank had no internal components corresponding to the wing tank, temperatures agreed with the flight measurements for wetted upper surface conditions, but not for unwetted conditions. It was concluded that if boundary conditions are carefully controlled, simulators are a useful way of evaluating actual flight temperatures.

  2. Aircraft electric field measurements: Calibration and ambient field retrieval

    NASA Technical Reports Server (NTRS)

    Koshak, William J.; Bailey, Jeff; Christian, Hugh J.; Mach, Douglas M.

    1994-01-01

    An aircraft locally distorts the ambient thundercloud electric field. In order to determine the field in the absence of the aircraft, an aircraft calibration is required. In this work a matrix inversion method is introduced for calibrating an aircraft equipped with four or more electric field sensors and a high-voltage corona point that is capable of charging the aircraft. An analytic, closed form solution for the estimate of a (3 x 3) aircraft calibration matrix is derived, and an absolute calibration experiment is used to improve the relative magnitudes of the elements of this matrix. To demonstrate the calibration procedure, we analyze actual calibration date derived from a Lear jet 28/29 that was equipped with five shutter-type field mill sensors (each with sensitivities of better than 1 V/m) located on the top, bottom, port, starboard, and aft positions. As a test of the calibration method, we analyze computer-simulated calibration data (derived from known aircraft and ambient fields) and explicitly determine the errors involved in deriving the variety of calibration matrices. We extend our formalism to arrive at an analytic solution for the ambient field, and again carry all errors explicitly.

  3. Design and analysis of aerospace structures at elevated temperatures. [aircraft, missiles, and space platforms

    NASA Technical Reports Server (NTRS)

    Chang, C. I.

    1989-01-01

    An account is given of approaches that have emerged as useful in the incorporation of thermal loading considerations into advanced composite materials-based aerospace structural design practices. Sources of structural heating encompass not only propulsion system heat and aerodynamic surface heating at supersonic speeds, but the growing possibility of intense thermal fluxes from directed-energy weapons. The composite materials in question range from intrinsically nonheat-resistant polymer matrix systems to metal-matrix composites, and increasingly to such ceramic-matrix composites as carbon/carbon, which are explicitly intended for elevated temperature operation.

  4. NASA Boeing 737 Aircraft Test Results from 1996 Joint Winter Runway Friction Measurement Program

    NASA Technical Reports Server (NTRS)

    Yager, Thomas J.

    1996-01-01

    A description of the joint test program objectives and scope is given together with the performance capability of the NASA Langley B-737 instrumented aircraft. The B-737 test run matrix conducted during the first 8 months of this 5-year program is discussed with a description of the different runway conditions evaluated. Some preliminary test results are discussed concerning the Electronic Recording Decelerometer (ERD) readings and a comparison of B-737 aircraft braking performance for different winter runway conditions. Detailed aircraft parameter time history records, analysis of ground vehicle friction measurements and harmonization with aircraft braking performance, assessment of induced aircraft contaminant drag, and evaluation of the effects of other factors on aircraft/ground vehicle friction performance will be documented in a NASA Technical Report which is being prepared for publication next year.

  5. A performance measure for evaluating aircraft landing trajectories

    NASA Technical Reports Server (NTRS)

    Witt, R. M.; Cook, G.

    1978-01-01

    A general performance index is developed for evaluating aircraft landing trajectories. The primary term in the index is the effect of noise on people residing near the air terminal. Other terms included are passenger comfort, fuel consumed, and the time spent in the near-terminal area. Models are developed for aircraft engine noise, passenger comfort, the population distribution about a specific airport, and the aircraft flight behavior. While this performance index may be used in computing optimal trajectories, it is also useful for comparing nonoptimal trajectories which, for one reason or another, may be worthy of consideration. Some examples of such comparisons are included through simulations of landing. The aircraft considered is a Boeing 737.

  6. Sea Surface Slope Statistics for Intermediate and Shore Scale Ocean Waves Measured Using a Low-Altitude Aircraft

    NASA Technical Reports Server (NTRS)

    Vandemack, Douglas; Crawford, Tim; Dobosy, Ron; Elfouhaily, Tanos; Busalacchi, Antonio J. (Technical Monitor)

    1999-01-01

    Ocean surface remote sensing techniques often rely on scattering or emission linked to shorter- scale gravity-capillary ocean wavelets. However, it is increasingly apparent that slightly longer wavelengths of O(10 to 500 cm) are vital components in the robust sea surface description needed to link varied global remote sensing data sets. This paper describes a sensor suite developed to examine sea surface slope variations in the field using an aircraft flying at very low altitude (below 30 m) and will also provide preliminary measurements detailing changes in slope characteristics versus sea state and friction velocity. Two-dimensional surface slope is measured using simultaneous range measurements from three compact short-range laser altimeters mounted in an equilateral triangle arrangement with spacing of about 1 m. In addition, all three lasers provide independent wave elevation profiles after GPS-aided correction for aircraft altitude. Laser range precision is 1 cm rms while vertical motion correction is 15 cm rms. The measurements are made along-track at approximately 1 m intervals setting the spatial scale of the measurement to cover waves of intermediate to long scale. Products available for this array then include surface elevation, two-dimensional slope distribution, and the cross- and along-track 1-D slope distributions. To complement the laser, a down-looking mm-wave radar scatterometer is centered within the laser array to measure radar backscatter simultaneously with the laser slope. The radar's footprint is nominally 1 m in diameter. Near-vertical radar backscatter is inversely proportional to the small-scale surface slope variance and to the tilt of the underlying (laser-measured) surface facet. Together the laser and radar data provide information on wave roughness from the longest scales down to about 1 cm. These measurements are complemented by aircraft turbulence probe data that provides robust surface flux information.

  7. Aircraft Wake Vortex Measurements at Denver International Airport

    NASA Technical Reports Server (NTRS)

    Dougherty, Robert P.; Wang, Frank Y.; Booth, Earl R.; Watts, Michael E.; Fenichel, Neil; D'Errico, Robert E.

    2004-01-01

    Airport capacity is constrained, in part, by spacing requirements associated with the wake vortex hazard. NASA's Wake Vortex Avoidance Project has a goal to establish the feasibility of reducing this spacing while maintaining safety. Passive acoustic phased array sensors, if shown to have operational potential, may aid in this effort by detecting and tracking the vortices. During August/September 2003, NASA and the USDOT sponsored a wake acoustics test at the Denver International Airport. The central instrument of the test was a large microphone phased array. This paper describes the test in general terms and gives an overview of the array hardware. It outlines one of the analysis techniques that is being applied to the data and gives sample results. The technique is able to clearly resolve the wake vortices of landing aircraft and measure their separation, height, and sinking rate. These observations permit an indirect estimate of the vortex circulation. The array also provides visualization of the vortex evolution, including the Crow instability.

  8. Aircraft Measurements on Microburst Development from Hydrometeor Evaporation.

    NASA Astrophysics Data System (ADS)

    Mahoney, William P., III; Rodi, Alfred R.

    1987-10-01

    During the Joint Airport Weather Studies (JAWS) project in 1982, the University of Wyoming's King Air research aircraft made observations of raindrop size distributions, vertical and horizontal air motions, and the temperature and moisture variables in and near precipitation shafts. This research examines the kinematic, thermodynamic, and microphysical characteristics of microburst-producing showers. Four precipitation showers with radar reflectivities of <35 dBZ were selected for study, three of which produced microbursts.An equivalent potential temperature (e) analysis, as well as vertical velocity measurements at cloud base, showed no strong evidence that the downdrafts were originating well above cloud base.A simple evaporation and downdraft model was used to examine the role of hydrometeor evaporation below cloud base as a microburst forcing mechanism. The one-dimensional model without entrainment provided the conceptual basis for microburst development by means of microphysical forcing alone. Cooling rates, caused by the evaporation of precipitation below cloud base, were calculated from the observed hydrometeor spectra and humidity profiles. The vertical profiles of the cooling rates were used to estimate downdraft magnitudes. The calculated downdraft speeds were in reasonable agreement with the observed speeds suggesting that, at least in these weak systems, subcloud evaporation was the predominant microburst forcing mechanism.The conditions favorable to microburst development were found to be consistent with previous studies. They included: 1) a deep, dry adiabatic layer below cloud base, 2) a high concentration of hydrometeors at or below cloud base, and 3) low humidity values in the descending parcel.

  9. Transonic Pitch Damping of a Delta Wing Aircraft Determined from Flight Measurements,

    DTIC Science & Technology

    1979-07-01

    and theoretical estimates where possible. 2. MATHEMATICAL MODEL In this section a mathematical model is developed which describes the aircraft ... longitudinal short period response to an elevator input. A basic linear model is extended to include possible non-linearities with incidence in the pitching

  10. Automated analyzer for aircraft measurements of atmospheric methane and total hydrocarbons

    NASA Technical Reports Server (NTRS)

    Cofer, W. R., III; Purgold, G. C.

    1981-01-01

    An automated methane/total hydrocarbon analyzer is presented, which can produce alternate methane/total hydrocarbon measurements every 7 seconds to provide the spatial resolution required for regional hydrocarbon measurements at aircraft speeds. The construction and sampling techniques developed for the aircraft mounted system are discussed. A technique to periodically measure atmosphere oxygen is incorporated into the analyzer to ensure accurate hydrocarbon measurements, and a data collection methodology is developed to minimize errors resulting from changes in flame ionization detector sensitivity at different altitudes. Aircraft data acquired at the 1979 Southeastern Virginia Urban Plume Study are also presented, which illustrate the application of the instrument to a troposphere pollution plume.

  11. Comparison of flight and wind tunnel measurements of jet noise for the XV-5B aircraft

    NASA Technical Reports Server (NTRS)

    Atencio, A., Jr.; Kirk, J. V.; Soderman, P. T.; Hall, L. P.

    1972-01-01

    Wind tunnel tests to determine noise data from scale model research aircraft are discussed. Comparisons are made between data obtained in wind tunnels and results of full scale flight tests. The acoustic measurements for the XV-5B V/STOL fan research aircraft are presented.

  12. New lidar concept for measuring the slant range transmission in aircraft landing approaches

    NASA Technical Reports Server (NTRS)

    Kohl, R. H.

    1977-01-01

    The single-scatter, single-wavelength, scalar-backscatter lidar equation is investigated to determine the transmission along a line from a point on the ground to what is known as the decision point on the 3 degree aircraft glide slope. It may be applied in aircraft landing approaches for measuring the slant range transmission.

  13. An experimental measurement of galactic cosmic radiation dose in conventional aircraft between San Francisco and London compared to theoretical values for conventional and supersonic aircraft

    NASA Technical Reports Server (NTRS)

    Wallace, R.; Boyer, M. F.

    1972-01-01

    These direct measurements are in fair agreement with computations made using a program which considers both basic cosmic ray atmospheric physics and the focusing effect of the earth's magnetic field. These measurements also agree with those made at supersonic jet aircraft altitudes in Rb-57 aircraft. It is concluded that experiments and theory show that the doses received at conventional jet aircraft altitudes are slightly higher than those encountered in supersonic flights at much higher altitudes.

  14. Comparisons between multiple in-situ aircraft turbulence measurements and radar in the troposphere

    NASA Astrophysics Data System (ADS)

    Dehghan, Armin; Hocking, Wayne K.; Srinivasan, Ramesh

    2014-10-01

    Networks of Windprofiler Radars have the capability to make significant contributions to severe weather forecasting (both on the ground and in the air) through the determination of real-time turbulence strengths, but the potential has still not been fully realized. In order to better understand the accuracy of profilers in determination of turbulence strengths, we have compared radar measurements made at the Harrow radar in Canada (located in Southwestern Ontario as part of the O-QNet radar network) with in-situ measurements made by multiple aircraft. These included measurements made both by commercial aircraft and dedicated research aircraft. Research aircraft (instrumented with accelerometers and GPS tracking devices) and radar data were analysed using structure function, spectral and spectral-width methods. Data were also recorded on-board commercial aircraft using accelerometer-based studies, and results were recorded for subsequent analyses. Over 92,000 commercial aircraft measurements, 4000 h of radar data, and 15 days of research-aircraft measurements were available for this study, although only a subset of the commercial aircraft data were useable. The radar-based spectral-width method occasionally produced anomalous negative values of the turbulence strength, usually associated with weak turbulence coupled with significant wind variability over scales of tens of kms, but the aircraft data also had limitations. For the commercial aircraft, frequent zeros were common, also associated with weak turbulence. With regard to the research aircraft measurements, it was found through both spectral and structure function analyses that spectral contaminants exist out to scales of many tens of metres (larger than often assumed), but proper allowance for these effects permitted good estimates of turbulence strength. Spatial and temporal variability was large, however, complicating comparisons with the radar. By comparing the in-situ data to the radar data, it has been

  15. Aircraft measurements of high average charges on cloud drops in layer clouds

    NASA Astrophysics Data System (ADS)

    Beard, Kenneth V.; Ochs, Harry T.; Twohy, Cynthia H.

    2004-07-01

    The first reliable aircraft measurements of characteristic cloud drop charges were obtained by utilizing a counterflow virtual impactor to substantially increase charge sensitivity and eliminate spurious contact charging that contaminated previous aircraft measurements. We find average drop charges more than an order of magnitude larger than expected from mountain surface measurements in similar clouds. Our evaluation of the data indicates that the high average charges on cloud drops originate in charge layers at the cloud boundaries and are carried into the cloud layer by vertical motions. These initial aircraft results demonstrate that cloud drop charges in layer clouds may be high enough to influence microphysical processes that promote precipitation.

  16. Dynamic Modeling Accuracy Dependence on Errors in Sensor Measurements, Mass Properties, and Aircraft Geometry

    NASA Technical Reports Server (NTRS)

    Grauer, Jared A.; Morelli, Eugene A.

    2013-01-01

    A nonlinear simulation of the NASA Generic Transport Model was used to investigate the effects of errors in sensor measurements, mass properties, and aircraft geometry on the accuracy of dynamic models identified from flight data. Measurements from a typical system identification maneuver were systematically and progressively deteriorated and then used to estimate stability and control derivatives within a Monte Carlo analysis. Based on the results, recommendations were provided for maximum allowable errors in sensor measurements, mass properties, and aircraft geometry to achieve desired levels of dynamic modeling accuracy. Results using other flight conditions, parameter estimation methods, and a full-scale F-16 nonlinear aircraft simulation were compared with these recommendations.

  17. Measurement of Phase Difference for Micromachined Gyros Driven by Rotating Aircraft

    PubMed Central

    Zhang, Zengping; Zhang, Fuxue; Zhang, Wei

    2013-01-01

    This paper presents an approach for realizing a phase difference measurement of a new gyro. A silicon micromachined gyro was mounted on rotating aircraft for aircraft attitude control. Aircraft spin drives the silicon pendulum of a gyro rotating at a high speed so that it can sense the transverse angular velocity of the rotating aircraft based on the gyroscopic precession principle when the aircraft has transverse rotation. In applications of the rotating aircraft single channel control system, such as damping in the attitude stabilization loop, the gyro signal must be kept in sync with the control signal. Therefore, the phase difference between both signals needs to be measured accurately. Considering that phase difference is mainly produced by both the micromachined part and the signal conditioning circuit, a mathematical model has been established and analyzed to determine the gyro's phase frequency characteristics. On the basis of theoretical analysis, a dynamic simulation has been done for a case where the spin frequency is 15 Hz. Experimental results with the proposed measurement method applied to a silicon micromachined gyro driven by a rotating aircraft demonstrate that it is effective in practical applications. Measured curve and numerical analysis of phase frequency characteristic are in accordance, and the error between measurement and simulation is only 5.3%. PMID:23966195

  18. Measurement of phase difference for micromachined gyros driven by rotating aircraft.

    PubMed

    Zhang, Zengping; Zhang, Fuxue; Zhang, Wei

    2013-08-21

    This paper presents an approach for realizing a phase difference measurement of a new gyro. A silicon micromachined gyro was mounted on rotating aircraft for aircraft attitude control. Aircraft spin drives the silicon pendulum of a gyro rotating at a high speed so that it can sense the transverse angular velocity of the rotating aircraft based on the gyroscopic precession principle when the aircraft has transverse rotation. In applications of the rotating aircraft single channel control system, such as damping in the attitude stabilization loop, the gyro signal must be kept in sync with the control signal. Therefore, the phase difference between both signals needs to be measured accurately. Considering that phase difference is mainly produced by both the micromachined part and the signal conditioning circuit, a mathematical model has been established and analyzed to determine the gyro's phase frequency characteristics. On the basis of theoretical analysis, a dynamic simulation has been done for a case where the spin frequency is 15 Hz. Experimental results with the proposed measurement method applied to a silicon micromachined gyro driven by a rotating aircraft demonstrate that it is effective in practical applications. Measured curve and numerical analysis of phase frequency characteristic are in accordance, and the error between measurement and simulation is only 5.3%.

  19. Some effects of the atmosphere and microphone placement on aircraft flyover noise measurements

    NASA Technical Reports Server (NTRS)

    Hosier, R. N.; Hilton, D. A.

    1975-01-01

    The effects of varying atmospheric conditions on certification-type noise measurements were studied. Tests were made under various atmospheric conditions at two test sites, Fresno, California, and Yuma, Arizona, using the same test aircraft, noise, and weather measuring equipment, and operating personnel. Measurements were made to determine the effects of the atmosphere and of microphone placement on aircraft flyover noise. The measurements were obtained for characterization of not only the acoustic signature of the test aircraft, but also specific atmospheric characteristics. Data are presented in the form of charts and tables which indicate that for a wide range of weather conditions, at both site locations, noise data were repeatable for similar aircraft operating conditions. The placement of microphones at ground level and at 1.2 m over both spaded sand and concrete illustrate the effects of ground reflections and surface impedance on the noise measurements.

  20. Hot-wire anemometry for in-flight measurement of aircraft wake vortices

    NASA Technical Reports Server (NTRS)

    Jacobsen, R. A.

    1977-01-01

    A development program has demonstrated that hot-wire anemometry can be used successfully on an aircraft in flight to make measurements of wake vortices produced by another aircraft. The probe, whose wires were made of platinum/rhodium, 10 microns in diameter, provides unambiguous results for inflow angles less than about 35 deg. off the probe axis. The high frequency response capability of the hot-wire system allows detailed measurement of the flow structure, and the study of aircraft hazards associated with wake turbulence.

  1. The LIULIN-3M Radiometer for Measuring Particle Doses in Space and on Aircraft

    NASA Technical Reports Server (NTRS)

    Stassinopoulos, E. G.; Stauffer, C. A.; Dachev, T. P.; Brucker, G. J.; Tomov, B. T.; Dimitrov, P. G.

    1999-01-01

    This paper reports on the development of a compact radiation monitor/dosimeter, the LIULIN-3M, and on extended measurements conducted on the ground and on commercial aircraft on domestic and international flights.

  2. Measurements of Radiation Exposure on Commercial Aircraft with the LIULIN-3M Instrument

    NASA Technical Reports Server (NTRS)

    Stassinopoulos, E. G.; Stauffer, C. A.; Dachev, T. P.; Brucker, G. J.; Tomov, B. T.; Dimitrov, P. G.

    1998-01-01

    This paper reports on the development of a compact radiation monitor/dosimeter, the LIULIN-3M, and on extended measurements conducted on the ground and on commercial aircraft on domestic and international flights.

  3. The LIULIN-3M Radiometer for Measuring Particle Doses in Space and on Aircraft

    NASA Technical Reports Server (NTRS)

    Stassinopoulos, E. G.; Stauffer, C. A.; Dachev, T. P.; Tomov, B. T.; Dimitrov, P. G.; Brucker, G. J.; Obenschain, Art (Technical Monitor)

    2002-01-01

    This paper reports on the development of a compact radiation monitor/dosimeter, the LIULIN-3M, and on extended measurements conducted on the ground and on commercial aircraft on domestic and international flights.

  4. Experimental flight test vibration measurements and nondestructive inspection on a USCG HC-130H aircraft

    NASA Technical Reports Server (NTRS)

    Moore, D. G.; Jones, C. R.; Mihelic, J. E.; Barnes, J. D.

    1998-01-01

    This paper presents results of experimental flight test vibration measurements and structural inspections performed by the Federal Aviation Administration's Airworthiness Assurance NDI Validation Center (AANC) at Sandia National Laboratories and the US Coast Guard Aircraft Repair and Supply Center (ARSC). Structural and aerodynamic changes induced by mounting a Forward Looking Infrared (FLIR) system on a USCG HC-130H aircraft are described. The FLIR adversely affected the air flow characteristics and structural vibration on the external skin of the aircraft's right main wheel well fairing. Upon initial discovery of skin cracking and visual observation of skin vibration in flight by the FLIR, a baseline flight without the FLIR was conducted and compared to other measurements with the FLIR installed. Nondestructive inspection procedures were developed to detect cracks in the skin and supporting structural elements and document the initial structural condition of the aircraft. Inspection results and flight test vibration data revealed that the FLIR created higher than expected flight loading and was the possible source of the skin cracking. The Coast Guard performed significant structural repair and enhancement on this aircraft, and additional in-flight vibration measurements were collected on the strengthened area both with and without the FLIR installed. After three months of further operational FLIR usage, the new aircraft skin with the enhanced structural modification was reinspected and found to be free of flaws. Additional US Coast Guard HC-130H aircraft are now being similarly modified to accommodate this FLIR system. Measurements of in- flight vibration levels with and without the FLIR installed, and both before and after the structural enhancement and repair were conducted on the skin and supporting structure in the aircraft's right main wheel fairing. Inspection results and techniques developed to verify the aircraft's structural integrity are discussed.

  5. Counting Particles Emitted by Stratospheric Aircraft and Measuring Size of Particles Emitted by Stratospheric Aircraft

    NASA Technical Reports Server (NTRS)

    Wilson, James Charles

    1994-01-01

    There were two principal objectives of the cooperative agreement between NASA and the University of Denver. The first goal was to modify the design of the ER-2 condensation nuclei counter (CNC) so that the effective lower detection limit would be improved at high altitudes. This improvement was sought because, in the instrument used prior to 1993, diffusion losses prevented the smallest detectable particles from reaching the detection volume of the instrument during operation at low pressure. Therefore, in spite of the sensor's ability to detect particles as small as 0.008 microns in diameter, many of these particles were lost in transport to the sensing region and were not counted. Most of the particles emitted by aircraft are smaller than 0.1 micron in diameter. At the start date of this work, May 1990, continuous sizing techniques available on the ER-2 were only capable of detecting particles larger than 0.17 micron. Thus, the second objective of this work was to evaluate candidate sizing techniques in an effort to gain additional information concerning the size of particles emitted by aircraft.

  6. An acoustic range for the measurement of the noise signature of aircraft during flyby operations

    NASA Technical Reports Server (NTRS)

    Hilton, D. A.; Henderson, H. R.

    1978-01-01

    The remotely operated multiple array acoustic range (ROMAAR), which has been developed to give direct measurement and display of aircraft noise in several measurement units during takeoff, landing, and flyby operations, is described. The ROMAAR, which provides information on the ground noise signature of aircraft, represents a unique combination of state-of-the-art digital and analog noise-recording methods, computer-controlled digital communication methods, radar tracking facilities, quick-look weather (profile) capabilities, and sophisticated data handling routines and facilities. The ROMAAR, which is operated by NASA, allows direct data feedback to the NASA Aircraft Noise Prediction Office. As many as 38 simultaneous noise measurements can be made for each aircraft overflight.

  7. Comparison of wind and turbulence measurements from Doppler lidar and instrumented aircraft

    NASA Technical Reports Server (NTRS)

    Huang, K. H.; Frost, W.; Ringnes, E. A.

    1985-01-01

    Wind fields were measured with the ground based lidar, NOAA Wave Propagation Laboratory and with the NASA B-57B instrumented aircraft. The remotely sensed winds are compared with the in situ aircraft measurements. Three flight plans were carried out during the two different field programs. At NASA/MSFC the aircraft circled while the lidar scanned conically and the aircraft flew 6 deg approach path along the fixed lidar beam. The aircraft flew an approach along the lidar beam directed south-north (parallel to the mountain range) and a climbout along the lidar beam which alternately shifted east-west (perpendicular to the mountain range). Turbulence intensities and spectra were calculated from the temporal fluctuations in the lidar-measured radial wind speed component. These field tests provided unique sets of data to examine the mean wind and turbulence measurements made by remote sensing instruments. The comparison of aircraft measured turbulence intensities and spectra with lidar time histories of radial wind speed were in good agreement.

  8. Comparison of ozone measurement techniques using aircraft, balloon, and ground-based measurements

    NASA Technical Reports Server (NTRS)

    Briehl, D.; Reck, G. M.

    1977-01-01

    In order to verify the ultraviolet absorption technique used in the Global Atmospheric Sampling Program, two flight experiments were conducted employing several techniques, both in situ and remote, for measuring atmospheric ozone. The first experiment used the NASA CV-990 equipped with an ultraviolet absorption ozone monitor and an ultraviolet spectrophotometer, a balloon ozonesonde, and a Dobson station for determining and comparing the ozone concentration data. A second experiment compared ozone data from an automated sampling system aboard a B-747 with data from a manned system installed on the NASA CV-990 during a cross-country flight with both aircraft following the same flight path separated by 32 kilometers.

  9. Aircraft operations and airborne measurement of perfluorotrimethylcyclohexane (PTCH) during ANATEX

    SciTech Connect

    Lee, R.N.; Busness, K.M.; Stunder, B.

    1988-09-01

    This paper describes PNL aircraft operations during the ANATEX field program and presents tracer concentration data obtained with the on-board analyzer for missions conducted on March 4, 1987. Also presented are preliminary sequential sampler data. Since final reduction of these data have not been completed, sequential sampler data have been normalized with respect to peak tracer loading to yield relative rather than absolute tracer concentrations in these sample. 3 refs., 7 figs., 2 tabs.

  10. Quasi-Static Viscoelasticity Loading Measurements of an Aircraft Tire

    NASA Technical Reports Server (NTRS)

    Mason, Angela J.; Tanner, John A.; Johnson, Arthur R.

    1997-01-01

    Stair-step loading, cyclic loading, and long-term relaxation tests were performed on an aircraft tire to observe the quasi-static viscoelastic response of the tire. The data indicate that the tire continues to respond viscoelastically even after it has been softened by deformation. Load relaxation data from the stair-step test at the 15,000-lb loading was fit to a monotonically decreasing Prony series.

  11. Aircraft and satellite measurement of ocean wave directional spectra using scanning-beam microwave radars

    NASA Technical Reports Server (NTRS)

    Jackson, F. C.; Walton, W. T.; Baker, P. L.

    1982-01-01

    A microwave radar technique for remotely measuring the vector wave number spectrum of the ocean surface is described. The technique, which employs short-pulse, noncoherent radars in a conical scan mode near vertical incidence, is shown to be suitable for both aircraft and satellite application, the technique was validated at 10 km aircraft altitude, where we have found excellent agreement between buoy and radar-inferred absolute wave height spectra.

  12. Compatibility check of measured aircraft responses using kinematic equations and extended Kalman filter

    NASA Technical Reports Server (NTRS)

    Klein, V.; Schiess, J. R.

    1977-01-01

    An extended Kalman filter smoother and a fixed point smoother were used for estimation of the state variables in the six degree of freedom kinematic equations relating measured aircraft responses and for estimation of unknown constant bias and scale factor errors in measured data. The computing algorithm includes an analysis of residuals which can improve the filter performance and provide estimates of measurement noise characteristics for some aircraft output variables. The technique developed was demonstrated using simulated and real flight test data. Improved accuracy of measured data was obtained when the data were corrected for estimated bias errors.

  13. Airborne Performance Measurement System Design: C-5 Aircraft

    DTIC Science & Technology

    1984-08-01

    simulator to the aircraft. In addition, these data may be utilized to predict or test the effects of training program *. modifications. The AFHRL...equipment diagnostic for the magnetic tape unit and controller. The second involves modification of the Confidence program to test only the equipment...IND 3 C: 57 S: 01 25-L-OXYGEN-QTY-LOW-LT 1 C: 57 25-L-OXYGEN--QTY- TEST -SW 1 C: 57 75-L-OXYGEN-QTY-IND 3 C: 57 S: 02 75-L-OXYGEN-QTY-LOW-LT 1 C: 57 75-L

  14. AGARD flight test techniques series. Volume 9: Aircraft exterior noise measurement and analysis techniques

    NASA Astrophysics Data System (ADS)

    Heller, H.

    1991-04-01

    Testing and analysis techniques to measure aircraft noise primarily for purposes of noise certification as specified by the 'International Civil Aviation Organization', ICAO are described. The relevant aircraft noise certification standards and recommended practices are presented in detail for subsonic jet aircraft, for heavy and light propeller-driven aircraft, and for helicopters. The practical execution of conducting noise certification tests is treated in depth. The characteristics and requirements of the acoustic and non-acoustic instrumentation for data acquisition and data processing are discussed, as are the procedures to determine the special noise measures - effective perceived noise level (EPNL) and maximum overall A-weighted noise level (L sub pA,max) - that are required for the noise certification of different types of aircraft. The AGARDograph also contains an extensive, although selective, discussion of test and analysis techniques for more detailed aircraft noise studies by means of either flight experiments or full-scale and model-scale wind tunnel experiments. Appendices provide supplementary information.

  15. Vibrations measured in the passenger cabins of two jet transport aircraft

    NASA Technical Reports Server (NTRS)

    Catherines, J. J.; Mixson, J. S.; Scholl, H. F.

    1975-01-01

    Accelerations in the lateral and vertical directions were measured at two locations on the floor of a three-jet-engine aircraft and at two locations on the floor of a two-jet-engine aircraft during a total of 13 flights, each of which included taxiing, takeoff, ascent, cruise, descent, and landing. Accelerations over the frequency range 0 to 25 Hz were recorded continuously on magnetic tape and were synchronized with the VGH recorders in the aircraft so that vibratory accelerations could be correlated with the operating conditions of the aircraft. From the results it was indicated that the methodology used in segmenting the data, which were obtained in a continuous and repetitive manner, contributes to establishing baseline data representative of the flight characteristics of aircraft. Significant differences among flight conductions were found to occur. The lateral accelerations were approximately 15 percent of the vertical accelerations during flight but as much as 50 to 100 percent of the vertical accelerations during ground operations. The variation between the responses of the two aircraft was not statistically significant. The results also showed that more than 90 percent of the vibratory energy measured during flight occurred in the 0- to 3.0-Hz frequency range. Generally, the vibration amplitudes were normally distributed.

  16. Aircraft measurements over Europe of an air pollution plume from Southeast Asia - aerosol and chemical characterization

    NASA Astrophysics Data System (ADS)

    Stohl, A.; Forster, C.; Huntrieser, H.; Mannstein, H.; McMillan, W. W.; Petzold, A.; Schlager, H.; Weinzierl, B.

    2007-02-01

    An air pollution plume from Southern and Eastern Asia, including regions in India and China, was predicted by the FLEXPART particle dispersion model to arrive in the upper troposphere over Europe on 24-25 March 2006. According to the model, the plume was exported from Southeast Asia six days earlier, transported into the upper troposphere by a warm conveyor belt, and travelled to Europe in a fast zonal flow. This is confirmed by the retrievals of carbon monoxide (CO) from AIRS satellite measurements, which are in excellent agreement with the model results over the entire transport history. The research aircraft DLR Falcon was sent into this plume west of Spain on 24 March and over Southern Europe on 25 March. On both days, the pollution plume was found close to the predicted locations and, thus, the measurements taken allowed the first detailed characterization of the aerosol content and chemical composition of an anthropogenic pollution plume after a nearly hemispheric transport event. The mixing ratios of CO, reactive nitrogen (NOy) and ozone (O3) measured in the Asian plume were all clearly elevated over a background that was itself likely elevated by Asian emissions: CO by 17-34 ppbv on average (maximum 60 ppbv) and O3 by 2-9 ppbv (maximum 22 ppbv). Positive correlations existed between these species, and a ΔO3/ΔCO slope of 0.25 shows that ozone was formed in this plume, albeit with moderate efficiency. Nucleation mode and Aitken particles were suppressed in the Asian plume, whereas accumulation mode aerosols were strongly elevated and correlated with CO. The suppression of the nucleation mode was likely due to the large pre-existing aerosol surface of the transported larger particles. Super-micron particles, likely desert dust, were found in part of the Asian pollution plume and also in surrounding cleaner air. The aerosol light absorption coefficient was enhanced in the plume (average values for individual plume encounters 0.25-0.70 Mm-1), as was the

  17. Aircraft measurements over Europe of an air pollution plume from Southeast Asia - aerosol and chemical characterization

    NASA Astrophysics Data System (ADS)

    Stohl, A.; Forster, C.; Huntrieser, H.; Mannstein, H.; McMillan, W. W.; Petzold, A.; Schlager, H.; Weinzierl, B.

    2006-12-01

    An air pollution plume from Southern and Eastern Asia, including regions in India and China, was predicted by the FLEXPART particle dispersion model to arrive in the upper troposphere over Europe on 24-25 March 2006. According to the model, the plume was exported from Southeast Asia only six days earlier, transported into the upper troposphere by a warm conveyor belt, and travelled to Europe in a fast zonal flow. This is confirmed by the retrievals of carbon monoxide (CO) from AIRS satellite measurements, which are in excellent agreement with the model results over the entire transport history. The research aircraft DLR Falcon was sent into this plume west of Spain on 24 March and over Southern Europe on 25 March. On both days, the pollution plume was indeed found close to the predicted locations and, thus, the measurements taken allowed the first detailed characterization of the aerosol content and chemical composition of an anthropogenic pollution plume after a nearly hemispheric transport event. The mixing ratios of CO, reactive nitrogen (NOy) and ozone (O3) measured in the Asian plume were all clearly elevated over a background that was itself likely elevated by Asian emissions: CO by 17-34 ppbv on average (maximum 60 ppbv) and O3 by 2-9 ppbv (maximum 22 ppbv). Positive correlations existed between these species, and a ΔO3/ΔCO slope of 0.25 shows that ozone was formed in this plume, albeit with moderate efficiency. Nucleation mode and Aitken particles were suppressed in the Asian plume, whereas accumulation mode aerosols were strongly elevated and correlated with CO. The suppression of the nucleation mode was likely due to the large pre-existing aerosol surface due to the transported larger particles. Super-micron particles, likely desert dust, were found in part of the Asian pollution plume and also in surrounding cleaner air. The aerosol light absorption coefficient was enhanced in the plume (average values for individual plume encounters 0.25-0.70 Mm-1

  18. Correction of static pressure on a research aircraft in accelerated flight using differential pressure measurements

    NASA Astrophysics Data System (ADS)

    Rodi, A. R.; Leon, D. C.

    2012-11-01

    A method is described that estimates the error in the static pressure measurement on an aircraft from differential pressure measurements on the hemispherical surface of a Rosemount model 858AJ air velocity probe mounted on a boom ahead of the aircraft. The theoretical predictions for how the pressure should vary over the surface of the hemisphere, involving an unknown sensitivity parameter, leads to a set of equations that can be solved for the unknowns - angle of attack, angle of sideslip, dynamic pressure and the error in static pressure - if the sensitivity factor can be determined. The sensitivity factor was determined on the University of Wyoming King Air research aircraft by comparisons with the error measured with a carefully designed sonde towed on connecting tubing behind the aircraft - a trailing cone - and the result was shown to have a precision of about ±10 Pa over a wide range of conditions, including various altitudes, power settings, and gear and flap extensions. Under accelerated flight conditions, geometric altitude data from a combined Global Navigation Satellite System (GNSS) and inertial measurement unit (IMU) system are used to estimate acceleration effects on the error, and the algorithm is shown to predict corrections to a precision of better than ±20 Pa under those conditions. Some limiting factors affecting the precision of static pressure measurement on a research aircraft are discussed.

  19. Acoustic measurements of F-4E aircraft operating in hush house, NSN 4920-02-070-2721

    NASA Astrophysics Data System (ADS)

    Miller, V. R.; Plzak, G. A.; Chinn, J. M.

    1981-09-01

    The primary purpose of this test program was to measure the acoustic environment in the hush house facility located at Kelly Air Force Base, Texas, during operation of the F-4E aircraft to ensure that aircraft structural acoustic design limits were not exceeded. The acoustic measurements showed that sonic fatigue problems are anticipated with the F-4E aircraft aft fuselage structure during operation in the hush house. The measured acoustic levels were less than those measured in an F-4E aircraft water cooled hush house at Hill AFB in the lower frequencies, but were increased over that measured during ground run up on some areas of the aircraft. It was recommended that the acoustic loads measured in this program should be specified in the structural design criteria for aircraft which will be subjected to hush house operation or defining requirements for associated equipment. Recommendations were also made to increase the fatigue life of the aft fuselage.

  20. Airdata calibration of a high-performance aircraft for measuring atmospheric wind profiles

    NASA Technical Reports Server (NTRS)

    Haering, Edward A., Jr.

    1990-01-01

    The research airdata system of an instrumented F-104 aircraft has been calibrated to measure winds aloft in support of the space shuttle wind measurement investigation at the National Aeronautics and Space Administration Ames Research Center Dryden Flight Research Facility. For this investigation, wind measurement accuracies comparable to those obtained from Jimsphere balloons were desired. This required an airdata calibration more accurate than needed for most aircraft research programs. The F-104 aircraft was equipped with a research pilot-static noseboom with integral angle-of-attack and flank angle-of-attack vanes and a ring-laser-gyro inertial reference unit. Tower fly-bys and radar acceleration-decelerations were used to calibrate Mach number and total temperature. Angle of attack and angle of sideslip were calibrated with a trajectory reconstruction technique using a multiple-state linear Kalman filter. The F-104 aircraft and instrumentation configuration, flight test maneuvers, data corrections, calibration techniques, and resulting calibrations and data repeatability are presented. Recommendations for future airdata systems on aircraft used to measure winds aloft are also given.

  1. Thermodynamic correction of particle concentrations measured by underwing probes on fast flying aircraft

    NASA Astrophysics Data System (ADS)

    Weigel, R.; Spichtinger, P.; Mahnke, C.; Klingebiel, M.; Afchine, A.; Petzold, A.; Krämer, M.; Costa, A.; Molleker, S.; Jurkat, T.; Minikin, A.; Borrmann, S.

    2015-12-01

    Particle concentration measurements with underwing probes on aircraft are impacted by air compression upstream of the instrument body as a function of flight velocity. In particular for fast-flying aircraft the necessity arises to account for compression of the air sample volume. Hence, a correction procedure is needed to invert measured particle number concentrations to ambient conditions that is commonly applicable for different instruments to gain comparable results. In the compression region where the detection of particles occurs (i.e. under factual measurement conditions), pressure and temperature of the air sample are increased compared to ambient (undisturbed) conditions in certain distance away from the aircraft. Conventional procedures for scaling the measured number densities to ambient conditions presume that the particle penetration speed through the instruments' detection area equals the aircraft speed (True Air Speed, TAS). However, particle imaging instruments equipped with pitot-tubes measuring the Probe Air Speed (PAS) of each underwing probe reveal PAS values systematically below those of the TAS. We conclude that the deviation between PAS and TAS is mainly caused by the compression of the probed air sample. From measurements during two missions in 2014 with the German Gulfstream G-550 (HALO - High Altitude LOng range) research aircraft we develop a procedure to correct the measured particle concentration to ambient conditions using a thermodynamic approach. With the provided equation the corresponding concentration correction factor ξ is applicable to the high frequency measurements of each underwing probe which is equipped with its own air speed sensor (e.g. a pitot-tube). ξ-values of 1 to 0.85 are calculated for air speeds (i.e. TAS) between 60 and 260 m s-1. From HALO data it is found that ξ does not significantly vary between the different deployed instruments. Thus, for the current HALO underwing probe configuration a parameterisation of

  2. Performance degradation of a typical twin engine commuter type aircraft in measured natural icing conditions

    NASA Technical Reports Server (NTRS)

    Ranaudo, R. J.; Mikkelsen, K. L.; Mcknight, R. C.; Perkins, P. J., Jr.

    1984-01-01

    The performance of an aircraft in various measured icing conditions was investigated. Icing parameters such as liquid water content, temperature, cloud droplet sizes and distributions were measured continuously while in icinig. Flight data wre reduced to provide plots of the aircraft drag polars and lift curves (CL vs. alpha) for the measured 'iced' condition as referenced to the uniced aircraft. These data were also reduced to provide plots of thrust horsepower required vs. single engine power available to show how icing affects engine out capability. It is found that performance degradation is primarily influenced by the amount and shape of the accumulated ice. Glaze icing caused the greatest aerodynamic performance penalties in terms of increased drag and reduction in lift while aerodynamic penalties due to rime icing were significantly lower. Previously announced in STAR as N84-13173

  3. Performance degradation of a typical twin engine commuter type aircraft in measured natural icing conditions

    NASA Technical Reports Server (NTRS)

    Ranaudo, R. J.; Mikkelsen, K. L.; Mcknight, R. C.; Perkins, P. J., Jr.

    1984-01-01

    The performance of an aircraft in various measured icing conditions was investigated. Icing parameters such as liquid water content, temperature, cloud droplet sizes and distributions were measured continuously while in icing. Flight data were reduced to provide plots of the aircraft drag polars and lift curves (CL vs. alpha) for the measured ""iced'' condition as referenced to the uniced aircraft. These data were also reduced to provide plots of thrust horsepower required vs. single engine power available to show how icing affects engine out capability. It is found that performance degradation is primarily influenced by the amount and shape of the accumulated ice. Glaze icing caused the greatest aerodynamic performance penalties in terms of increased drag and reduction in lift while aerodynamic penalties due to rime icing were significantly lower.

  4. Dependence of Dynamic Modeling Accuracy on Sensor Measurements, Mass Properties, and Aircraft Geometry

    NASA Technical Reports Server (NTRS)

    Grauer, Jared A.; Morelli, Eugene A.

    2013-01-01

    The NASA Generic Transport Model (GTM) nonlinear simulation was used to investigate the effects of errors in sensor measurements, mass properties, and aircraft geometry on the accuracy of identified parameters in mathematical models describing the flight dynamics and determined from flight data. Measurements from a typical flight condition and system identification maneuver were systematically and progressively deteriorated by introducing noise, resolution errors, and bias errors. The data were then used to estimate nondimensional stability and control derivatives within a Monte Carlo simulation. Based on these results, recommendations are provided for maximum allowable errors in sensor measurements, mass properties, and aircraft geometry to achieve desired levels of dynamic modeling accuracy. Results using additional flight conditions and parameter estimation methods, as well as a nonlinear flight simulation of the General Dynamics F-16 aircraft, were compared with these recommendations

  5. Acoustic measurements of F-15 aircraft operating in hush house, NSN 4920-02-070-2721

    NASA Astrophysics Data System (ADS)

    Miller, V. R.; Plzak, G. A.; Chinn, J. M.

    1981-09-01

    The purpose of this test program was to measure the acoustic environment in the hush house facility located at Kelly Air Force Base, Texas, during operation of the F-15 aircraft to ensure that aircraft structural acoustic design limits were not exceeded. The acoustic measurements showed that no potential sonic fatigue problems are anticipated with the F-15 aircraft structure during operation in the hush house. However, since these acoustic levels were increased over those measuring during run up on a concrete pad, it is recommended that F-15 equipment qualification levels be checked. The data indicated that the noise field within the hush house is diffuse and that the acoustical energy in the hangar area is radiated from the region between the engine exhaust and the hush house muffler front edge toward the forward part of the hangar.

  6. Automated Measurement of Crack Length and Load Line Displacement at Elevated Temperature,

    DTIC Science & Technology

    1988-02-01

    LINE DISPLACEMENT AT ELEVATED TEMPERATURE Test results reported in the literature show that, in creep cracking tests at elevated temperature under steady...set-up developed for elevated temperature creep cracking test in which crack length was measured with the electrical potential drop method and load...reported in the literature show that in creep cracking tests at elevated temperature under steady load, the crack growth rate correlates best with the

  7. Calibration and demonstration of a condensation nuclei counting system for airborne measurements of aircraft exhausted particles

    NASA Astrophysics Data System (ADS)

    Cofer, Wesley R.; Anderson, Bruce E.; Winstead, Edward L.; Bagwell, Donald R.

    A system of multiple continuous-flow condensation nuclei counters (CNC) was assembled, calibrated, and demonstrated on a NASA T-39 Sabreliner jet aircraft. The mission was to penetrate the exhaust plumes and/or contrails of other subsonic jet aircraft and determine the concentrations of submicrometer diameter aerosol particles. Mission criteria required rapid response measurements ( ˜ 1 s) at aircraft cruise altitudes (9-12 km). The CNC sampling system was optimized to operate at 160 Torr. Aerosol samples were acquired through an externally mounted probe. Installed downstream of the probe was a critical flow orifice that provided sample to the CNC system. The orifice not only controlled volumetric flow rate, but also dampened probe pressure/flow oscillations encountered in the turbulent aircraft-wake vortex environment. Laboratory calibrations with NaCl particles under representative conditions are reported that indicate small amounts of particle loss and a maximum measurement efficiency of ˜ 75% for particles with diameters ranging from ⩾ 0.01- ⩽ 0.18 μm Data from exhaust/contrail samplings of a NASA B757 and DC-8 at cruise altitude are discussed. Data include exhaust/contrail measurements made during periods in which the B757 port jet engine burned low-sulfur fuel while the starboard engine simultaneously burned specially prepared high-sulfur fuel. The data discussed highlight the CNC systems performance, and introduce new observations pertinent to the behavior of sulfur in aircraft exhaust aerosol chemistry.

  8. A test technique for measuring lightning-induced voltages on aircraft electrical circuits

    NASA Technical Reports Server (NTRS)

    Walko, L. C.

    1974-01-01

    The development of a test technique used for the measurement of lightning-induced voltages in the electrical circuits of a complete aircraft is described. The resultant technique utilizes a portable device known as a transient analyzer capable of generating unidirectional current impulses similar to lightning current surges, but at a lower current level. A linear relationship between the magnitude of lightning current and the magnitude of induced voltage permitted the scaling up of measured induced values to full threat levels. The test technique was found to be practical when used on a complete aircraft.

  9. A novel aircraft-based tandem mass spectrometer for atmospheric ion and trace gas measurements

    NASA Astrophysics Data System (ADS)

    Moehler, O.; Reiner, Th.; Arnold, F.

    1993-05-01

    The general design and operation of a novel aircraft-based triple-quadrupole mass spectrometer (TQMS) developed for the improved detection and collisional analysis of atmospheric ions and trace gases are described. The instrument is also suitable for laboratory collision-induced dissociation measurements, studies of ion-molecule reactions, and analytical applications. Highly sensitive and selective trace gas detection by chemical ionization mass spectrometry is also possible using a novel ion injection technique. Result of aircraft-based measurements made with the TQMS are summarized.

  10. Summary of aircraft results for 1978 southeastern Virginia urban plume measurement study of ozone, nitrogen oxides, and methane

    NASA Technical Reports Server (NTRS)

    Gregory, G. L.; Wornom, D. E.; Mathis, J. J., Jr.; Sebacher, D. I.

    1980-01-01

    Ozone production was determined from aircraft and surface in situ measurements, as well as from an airborne laser absorption spectrometer. Three aircraft and approximately 10 surface stations provided air-quality data. Extensive meteorological, mixing-layer-height, and ozone-precursor data were also measured. Approximately 50 hrs (9 flight days) of data from the aircraft equipped to monitor ozone, nitrogen oxides, dewpoint temperature, and temperature are presented. In addition, each experiment conducted is discussed.

  11. Counting particles emitted by stratospheric aircraft and measuring size of particles emitted by stratospheric aircraft

    NASA Technical Reports Server (NTRS)

    Wilson, James Charles

    1994-01-01

    The ER-2 condensation nuclei counter (CNC) has been modified to reduce the diffusive losses of particles within the instrument. These changes have been successful in improving the counting efficiency of small particles at low pressures. Two techniques for measuring the size distributions of particles with diameters less than 0.17 micrometers have been evaluated. Both of these methods, the differential mobility analyzer (DMA) and the diffusion battery, have fundamental problems that limit their usefulness for stratospheric applications. We cannot recommend either for this application. Newly developed, alternative methods for measuring small particles include inertial separation with a low-loss critical orifice and thin-plate impactor device. This technique is now used to collect particles in the multisample aerosol collector housed in the ER-2 CNC-2, and shows some promise for particle size measurements when coupled with a CNC as a counting device. The modified focused-cavity aerosol spectrometer (FCAS) can determine the size distribution of particles with ambient diameters as small as about 0.07 micrometers. Data from this instrument indicates the presence of a nuclei mode when CNC-2 indicates high concentrations of particles, but cannot resolve important parameters of the distribution.

  12. LASE measurements of water vapor and aerosol profiles during the Plains Elevated Convection at Night (PECAN) field experiment

    NASA Astrophysics Data System (ADS)

    Nehrir, A. R.; Ferrare, R. A.; Kooi, S. A.; Butler, C. F.; Notari, A.; Hair, J. W.; Collins, J. E., Jr.; Ismail, S.

    2015-12-01

    The Lidar Atmospheric Sensing Experiment (LASE) system was deployed on the NASA DC-8 aircraft during the Plains Elevated Convection At Night (PECAN) field experiment, which was conducted during June-July 2015 over the central and southern plains. LASE is an active remote sensor that employs the differential absorption lidar (DIAL) technique to measure range resolved profiles of water vapor and aerosols above and below the aircraft. The DC-8 conducted nine local science flights from June 30- July 14 where LASE sampled water vapor and aerosol fields in support of the PECAN primary science objectives relating to better understanding nocturnal Mesoscale Convective Systems (MCSs), Convective Initiation (CI), the Low Level Jet (LLJ), bores, and to compare different airborne and ground based measurements. LASE observed large spatial and temporal variability in water vapor and aerosol distributions in advance of nocturnal MCSs, across bores resulting from MCS outflow boundaries, and across the LLJ associated with the development of MCSs and CI. An overview of the LASE data collected during the PECAN field experiment will be presented where emphasis will be placed on variability of water vapor profiles in the vicinity of severe storms and intense convection in the central and southern plains. Preliminary comparisons show good agreement between coincident LASE and radiosonde water vapor profiles. In addition, an advanced water vapor DIAL system being developed at NASA Langley will be discussed.

  13. Analysis of Aircraft Clusters to Measure Sector-Independent Airspace Congestion

    NASA Technical Reports Server (NTRS)

    Bilimoria, Karl D.; Lee, Hilda Q.

    2005-01-01

    The Distributed Air/Ground Traffic Management (DAG-TM) concept of operations* permits appropriately equipped aircraft to conduct Free Maneuvering operations. These independent aircraft have the freedom to optimize their trajectories in real time according to user preferences; however, they also take on the responsibility to separate themselves from other aircraft while conforming to any local Traffic Flow Management (TFM) constraints imposed by the air traffic service provider (ATSP). Examples of local-TFM constraints include temporal constraints such as a required time of arrival (RTA), as well as spatial constraints such as regions of convective weather, special use airspace, and congested airspace. Under current operations, congested airspace typically refers to a sector(s) that cannot accept additional aircraft due to controller workload limitations; hence Dynamic Density (a metric that is indicative of controller workload) can be used to quantify airspace congestion. However, for Free Maneuvering operations under DAG-TM, an additional metric is needed to quantify the airspace congestion problem from the perspective of independent aircraft. Such a metric would enable the ATSP to prevent independent aircraft from entering any local areas of congestion in which the flight deck based systems and procedures may not be able to ensure separation. This new metric, called Gaggle Density, offers the ATSP a mode of control to regulate normal operations and to ensure safety and stability during rare-normal or off-normal situations (e.g., system failures). It may be difficult to certify Free Maneuvering systems for unrestricted operations, but it may be easier to certify systems and procedures for specified levels of Gaggle Density that could be monitored by the ATSP, and maintained through relatively minor flow-rate (RTA type) restrictions. Since flight deck based separation assurance is airspace independent, the challenge is to measure congestion independent of sector

  14. Daytime aircraft HONO Measurements over water surface during NOMASS Field Study

    NASA Astrophysics Data System (ADS)

    Ye, C.; Pu, D.; Zhou, X.; Stutz, J.; Mauldin, R.; Cantrell, C. A.; Weinheimer, A. J.; Knapp, D. J.; Haggerty, J. A.; Campos, T. L.; Guenther, A. B.; Kaser, L.; Jensen, J. B.

    2013-12-01

    The NOMDASS (Nitrogen, Oxidants, Mercury and Aerosol Distributions, Sources and Sinks) study is an NSF sponsored airborne experiment, integrating 3 PI-initiated projects: the NAAMEX (The North American Airborne Mercury Experiment), the SOAS (Southern Oxidant and Aerosol Study), and the TROPHONO (TROPospheric HONO) projects. During the NOMDASS field campaign from June 1 to July 15, 2013, based in Smyrna, TN, HONO was measured onboard NCAR's C-130 research aircraft in 19 research flights. In order to study in situ HONO production (i.e., volume production) within air masses, four research flights were designed and conducted over open waters to eliminate potential HONO contributions from ground surface sources. In the 2 inflow flights over the Atlantic Ocean off of the Carolina coast, up to 15 ppt HONO was observed in the clean marine boundary layer (MBL). To sustain the observed levels of HONO, a significant in situ HONO source, at a rate of ~60 ppt hr-1, must exist. Since the NOx mixing ratio was very low, ~ 40 ppt, NOx is unlikely to be a significant HONO precursor in the clean MBL. On the other hand, significant levels of particular nitrate were observed, up to 50 ppt. Photolysis of particulate nitrate may be a significant or even a major HONO source and may be an important re-NOx-ification pathway in this clean and low-NOx marine environment. In a flight over the Gulf of Mexico off of Houston, up to 40 ppt HONO was observed in the Houston plume; in a flight over Lake Michigan, up to 60 ppt HONO was observed in the Chicago plume. At elevated concentrations in urban plumes, HONO may be a significant OH precursor and may play an important role in the photochemical evolution of urban plume.

  15. Oceanographic measurement capabilities of the NASA P-3 aircraft. [ERS-1 mission

    NASA Technical Reports Server (NTRS)

    Mollo-Christensen, Erik; Jackson, F. C.; Walsh, E. J.; Hoge, F.

    1986-01-01

    Instrumentation on NASA P3 aircraft available to provide ground truth for ERS-1 is described. The wave sensors include the 36 GHz Surface Contour Radar (SCR), the Ku-band Radar Ocean Wave Spectrometer (ROWS), and the Airborne Oceanographic Lidar. The other sensors include a C-band scatterometer, video camera, radiation thermometer, and AXRTs. The SCR and ROWS directional spectrum measurements are discussed. When planning for an underflight mission, the limited endurance of the aircraft (6 hr) and flight cost (2.7 K$/hr) must be considered. The advantage of the redundancy afforded by the several wave instruments is another important consideration.

  16. In situ measurements of Arctic atmospheric trace constituents from an aircraft

    NASA Technical Reports Server (NTRS)

    Reck, G. M.; Briehl, D.; Nyland, T. W.

    1977-01-01

    In situ measurements of the ambient concentrations of several atmospheric trace constituents were obtained using instruments installed on board the NASA Convair 990 aircraft at altitudes up to 12.5 kilometers over Alaska and the Arctic Ocean. Concentration data on ozone, carbon monoxide, water vapor, and particles larger than 0.5 micrometer in diameter were acquired.

  17. Ozonesonde and aircraft measurements in the tropical West Pacific from the CAST field campaign

    NASA Astrophysics Data System (ADS)

    Newton, Richard; Vaughan, Geraint; Ricketts, Hugo

    2015-04-01

    The Coordinated Airborne Studies in the Tropics (CAST) campaign comprised of ozonesonde launches and an aircraft campaign in the West Pacific in January-March 2014. Previous field campaigns in this region have highlighted an area to the east of Papua New Guinea and near the Solomon Islands as sources of deep convection and anomalously low ozone in the tropical tropopause layer (TTL). The CAST campaign provides a unique dataset of ozonesonde launches from Manus Island, Papua New Guinea, close to the hypothesized source region. CAST was performed in coordination with two sister campaigns, CONTRAST and ATTREX, bringing the FAAM BAe 146, NCAR Gulfstream V and NASA Global Hawk aircraft respectively to Guam. The aircraft campaign allowed an unprecedented comparison between ozonesondes and aircraft, which was used to verify the ozonesonde measurements and support the choice of background correction; this correction is of paramount importance in the tropics as the background constitutes half of the measured signal. The data obtained from the CAST ozonesondes suggest that the lowest ozone concentrations, at ~15 ppb, found in the tropical tropopause layer were accompanied by easterly winds from an area of deep convection, suggesting the air was lifted quickly from the marine boundary layer. The evidence from the CAST campaign suggests that the anomalously low near-zero ozone measured during previous campaigns in the tropical West Pacific is an artefact of the ozonesonde behaviour at low pressures (high altitude) - the low-ozone measurements can be recreated with the CAST ozonesondes if the background is not properly treated.

  18. Field Tests of a Laser Raman Measurement System for Aircraft Engine Exhaust Emissions

    DTIC Science & Technology

    1974-10-01

    practical one. The advantages of optical exhaust gas measurements versus probing systems has been demonstrated. It now remains to solve the remaining...Raman system NOVA digital data processor has the capability to service such additional measurements. If velocity information is desired a study should be...AD/A-003 648 FIELD TESTS OF A LASER RAMAN MEASURE- MENT SYSTEM FOR AIRCRAFT ENGINE EXHAUST EMISSIONS Donald A. Leunard Avoo Everett Researoh

  19. A summary of recent aircraft/ground vehicle friction measurement tests

    NASA Technical Reports Server (NTRS)

    Yager, Thomas J.

    1988-01-01

    Tests were carried out to evaluate a variety of runway surface types and wetness conditions, using specially instrumented NASA B-737 and B-727 aircraft and several ground friction measuring devices. The performance data for aircraft braking on dry, wet, snow-covered, and ice-covered runway conditions are presented and compared to ground-vehicle friction data obtained under similar runway conditions. The relationships between ground vehicles and the aircraft friction data are identified, and the effects on friction of major test parameters, such as the speed, the tire characteristics, and the type of surface-contaminant are discussed. The results demonstrated that properly maintained and calibrated ground vehicles can be used to monitor the runway friction conditions.

  20. Aircraft cabin ozone measurements on B747-100 and B747-SP aircraft: Correlations with atmospheric ozone and ozone encounter statistics

    NASA Technical Reports Server (NTRS)

    Perkins, P. J.; Holdeman, J. D.; Gauntner, D. J.

    1978-01-01

    Simultaneous measurements of atmospheric (outside) ozone concentration and ozone levels in the cabin of the B747-100 and B747-SP airliners were made by NASA to evaluate the aircraft cabin ozone contamination problem. Instrumentation on these aircraft measured ozone from an outside probe and at one point in the cabin. Average ozone in the cabin of the B747-100 was 39 percent of the outside. Ozone in the cabin of the B747-SP measured 82 percent of the outside, before corrective measures. Procedures to reduce the ozone in this aircraft included changes in the cabin air circulation system, use of the high-temperature 15th stage compressor bleed, and charcoal filters in the inlet cabin air ducting, which as separate actions reduced the ozone to 58, 19 and 5 percent, respectively. The potential for the NASA instrumented B747 aircraft to encounter high levels of cabin ozone was derived from atmospheric oxone measurements on these aircraft. Encounter frequencies for two B747-100's were comparable even though the route structures were different. The B747-SP encountered high ozone than did the B747-100's.

  1. Aircraft-based measurements of the carbon footprint of Indianapolis.

    PubMed

    Mays, Kelly L; Shepson, Paul B; Stirm, Brian H; Karion, Anna; Sweeney, Colm; Gurney, Kevin R

    2009-10-15

    The quantification of greenhouse gas emissions requires high precision measurements made with high spatial resolution. Here we describe measurements of carbon dioxide (CO2) and methane (CH4) conducted using Purdue University's Airborne Laboratory for Atmospheric Research (ALAR), aimed at the quantification of the "footprints" for these greenhouse gases for Indianapolis, IN. A cavity ring-down spectrometer measured atmospheric concentrations, and flask samples were obtained at various points for comparison. Coupled with pressure, temperature, and model-derived horizontal winds, these measurements allow for flux estimation. Long horizontal transects were flown perpendicular to the wind downwind of the city. Emissions were calculated using the wind speed and the difference between the concentration in the plume and the background concentration. A kriging method is applied to interpolate the measured values to a vertical plane traced out by the flight pattern within the mixed layer. Results show the urban plume is clearly distinguishable in the downwind concentrations for most flights. Additionally, there is large variability in the measured day-to-day emissions fluxes as well as in the relative CH4 and CO2 fluxes. Uncertainties in the method are discussed, and its potential utilityin determining sector-based emission factors is shown.

  2. Should helicopter noise be measured differently from other aircraft noise? A review of the psychoacoustic literature

    NASA Technical Reports Server (NTRS)

    Molino, J. A.

    1982-01-01

    A review of 34 studies indicates that several factors or variables might be important in providing a psychoacoustic foundation for measurements of the noise from helicopters. These factors are phase relations, tail rotor noise, repetition rate, crest level, and generic differences between conventional aircraft and helicopters. Particular attention was given to the impulsive noise known as blade slap. Analysis of the evidence for and against each factor reveals that, for the present state of scientific knowledge, none of these factors should be regarded as the basis for a significant noise measurement correction due to impulsive blade slap. The current method of measuring effective perceived noise level for conventional aircraft appears to be adequate for measuring helicopter noise as well.

  3. Accurate Measurements of Aircraft Engine Soot Emissions Using a CAPS PMssa Monitor

    NASA Astrophysics Data System (ADS)

    Onasch, Timothy; Thompson, Kevin; Renbaum-Wolff, Lindsay; Smallwood, Greg; Make-Lye, Richard; Freedman, Andrew

    2016-04-01

    We present results of aircraft engine soot emissions measurements during the VARIAnT2 campaign using CAPS PMssa monitors. VARIAnT2, an aircraft engine non-volatile particulate matter (nvPM) emissions field campaign, was focused on understanding the variability in nvPM mass measurements using different measurement techniques and accounting for possible nvPM sampling system losses. The CAPS PMssa monitor accurately measures both the optical extinction and scattering (and thus single scattering albedo and absorption) of an extracted sample using the same sample volume for both measurements with a time resolution of 1 second and sensitivity of better than 1 Mm-1. Absorption is obtained by subtracting the scattering signal from the total extinction. Given that the single scattering albedo of the particulates emitted from the aircraft engine measured at both 630 and 660 nm was on the order of 0.1, any inaccuracy in the scattering measurement has little impact on the accuracy of the ddetermined absorption coefficient. The absorption is converted into nvPM mass using a documented Mass Absorption Coefficient (MAC). Results of soot emission indices (mass soot emitted per mass of fuel consumed) for a turbojet engine as a function of engine power will be presented and compared to results obtained using an EC/OC monitor.

  4. Measurements of Past Ice Sheet Elevations in Interior West Antarctica.

    PubMed

    Ackert; Barclay; Borns; Calkin; Kurz; Fastook; Steig

    1999-10-08

    A lateral moraine band on Mount Waesche, a volcanic nunatak in Marie Byrd Land, provides estimates of past ice sheet surface elevations in West Antarctica. Helium-3 and chlorine-36 surface exposure ages indicate that the proximal part of the moraine, up to 45 meters above the present ice surface, was deposited about 10,000 years ago, substantially later than the maximum ice extent in the Ross Embayment. The upper distal part of the moraine may record multiple earlier ice sheet high stands. A nonequilibrium ice sheet model predicts a delay of several thousand years in maximum ice levels at Mount Waesche relative to the maximum ice extent in the Ross Sea. The glacial geologic evidence, coupled with the ice sheet model, indicates that the contribution of the Ross Sea sector of the West Antarctic Ice Sheet to Holocene sea level rise was only about 3 meters. These results eliminate West Antarctic ice as the principle source of the large meltwater pulse during the early Holocene.

  5. Anomalous elevated radiocarbon measurements of PM2.5

    NASA Astrophysics Data System (ADS)

    Buchholz, Bruce A.; Fallon, Stewart J.; Zermeño, Paula; Bench, Graham; Schichtel, Bret A.

    2013-01-01

    Two-component models are often used to determine the contributions made by fossil fuel and natural sources of carbon in airborne particulate matter (PM). The models reduce thousands of actual sources to two end members based on isotopic signature. Combustion of fossil fuels produces PM free of carbon-14 (14C). Wood or charcoal smoke, restaurant fryer emissions, and natural emissions from plants produce PM with the contemporary concentration of 14C approximately 1.2 × 10-1214C/C. Such data can be used to estimate the relative contributions of fossil fuels and biogenic aerosols to the total aerosol loading and radiocarbon analysis is becoming a popular source apportionment method. Emissions from incinerators combusting medical or biological wastes containing tracer 14C can skew the 14C/C ratio of PM, however, so critical analysis of sampling sites for possible sources of elevated PM needs to be completed prior to embarking on sampling campaigns. Results are presented for two ambient monitoring sites in different areas of the United States where 14C contamination is apparent. Our experience suggests that such contamination is uncommon but is also not rare (∼10%) for PM sampling sites.

  6. Measurements of Nucleation-Mode Particle Size Distributions in Aircraft Plumes during SULFUR 6

    NASA Technical Reports Server (NTRS)

    Brock, Charles A.; Bradford, Deborah G.

    1999-01-01

    This report summarizes the participation of the University of Denver in an airborne measurement program, SULFUR 6, which was undertaken in late September and early October of 1998 by the Deutsches Zentrum fur Luft und Raumfahrt (DLR). Scientific findings from two papers that have been published or accepted and from one manuscript that is in preparation are presented. The SULFUR 6 experiment was designed to investigate the emissions from subsonic aircraft to constrain calculations of possible atmospheric chemical and climatic effects. The University of Denver effort contributed toward the following SULFUR 6 goals: (1) To investigate the relationship between fuel sulfur content (FSC--mass of sulfur per mass of fuel) and particle number and mass emission index (El--quantity emitted per kg of fuel burned); (2) To provide upper and lower limits for the mass conversion efficiency (nu) of fuel sulfur to gaseous and particulate sulfuric acid; (3) To constrain models of volatile particle nucleation and growth by measuring the particle size distribution between 3 and 100 nm at aircraft plume ages ranging from 10(exp -1) to 10(exp 3) s; (4) To determine microphysical and optical properties and bulk chemical composition of soot particles in aircraft exhaust; and (5) To investigate the differences in particle properties between aircraft plumes in contrail and non-contrail situations. The experiment focused on emissions from the ATTAS research aircraft (a well characterized, but older technology turbojet) and from an in-service Boeing 737-300 aircraft provided by Lufthansa, with modem, high-bypass turbofan engines. Measurements were made from the DLR Dassault Falcon 900 aircraft, a modified business jet. The Atmospheric Effects of Aviation Program (AEAP) provided funding to operate an instrument, the nucleation-mode aerosol size spectrometer (N-MASS), during the SULFUR 6 campaign and to analyze the data. The N-MASS was developed at the University of Denver with the support of

  7. Comparative Optical Measurements of Airspeed and Aerosols on a DC-8 Aircraft

    NASA Technical Reports Server (NTRS)

    Bogue, Rodney; McGann, Rick; Wagener, Thomas; Abbiss, John; Smart, Anthony

    1997-01-01

    NASA Dryden supported a cooperative flight test program on the NASA DC-8 aircraft in November 1993. This program evaluated optical airspeed and aerosol measurement techniques. Three brassboard optical systems were tested. Two were laser Doppler systems designed to measure free-stream-referenced airspeed. The third system was designed to characterize the natural aerosol statistics and airspeed. These systems relied on optical backscatter from natural aerosols for operation. The DC-8 aircraft carried instrumentation that provided real-time flight situation information and reference data on the aerosol environment. This test is believed to be the first to include multiple optical airspeed systems on the same carrier aircraft, so performance could be directly compared. During 23 hr of flight, a broad range of atmospheric conditions was encountered, including aerosol-rich layers, visible clouds, and unusually clean (aerosol-poor) regions. Substantial amounts of data were obtained. Important insights regarding the use of laser-based systems of this type in an aircraft environment were gained. This paper describes the sensors used and flight operations conducted to support the experiments. The paper also briefly describes the general results of the experiments.

  8. Coupled Gravity and Elevation Measurements of Ice Sheet Mass Change

    NASA Technical Reports Server (NTRS)

    Jezek, K. C.

    2005-01-01

    We measured surface gravity and position at ten locations about two glaciological measurement networks located on the South-central Greenland Ice during June 2004. Six of the individual sites of the first network were occupied the previous year. At the repeat sites we were able to measure annual accumulation rate and surface displacement by referencing measurements to aluminum poles left in the firn the previous year. We occupied 4 additional sites at a second measurement network for the first time since initial observations were last made at the network in 1981. At each individual site, we operated a GPS unit for 90 minutes - the unit was operated simultaneously with a base station unit in Sondrestrom Fjord so as to enable differential, post-processing of the data. We installed an aluminum, accumulation-rate-pole at each site. The base section of the pole also served as the mount for the GPS antenna. A new, Scintrex gravimeter was used at each site and relative gravity measurements were tied to the network of absolute gravity stations in Sondrestrom. We measured snow physical properties in two shallow pits. This report summarizes our observations and data analysis.

  9. Aircraft measurements of trace gases and particles near the tropopause

    NASA Technical Reports Server (NTRS)

    Falconer, P.; Pratt, R.; Detwiler, A.; Chen, C. S.; Hogan, A.; Bernard, S.; Krebschull, K.; Winters, W.

    1983-01-01

    Research activities which were performed using atmospheric constituent data obtained by the NASA Global Atmospheric Sampling Program are described. The characteristics of the particle size spectrum in various meteorological settings from a special collection of GASP data are surveyed. The relationship between humidity and cloud particles is analyzed. Climatological and case studies of tropical ozone distributions measured on a large number of flights are reported. Particle counter calibrations are discussed as well as the comparison of GASP particle data in the upper troposphere with other measurements at lower altitudes over the Pacific Ocean.

  10. Lidar Measurements of Methane and Applications for Aircraft and Spacecraft

    NASA Technical Reports Server (NTRS)

    Riris, Haris; Numata, Kenji; Abshire, James; Li, Steve; Wu, Stewart; Krainak, Michael; Sun, Xiaoli

    2010-01-01

    Atmospheric methane levels have remained relatively constant over the last decade around 1.78 parts per million (ppm) but observations since 2007 show that levels may be increasing. This trend may be caused by increased fossil fuel production, rice farming, livestock and landfills, but the underlying causes are quite uncertain. One hypothesis is that reservoirs of carbon trapped in the permafrost regions of northern Canada, Europe, and Siberia thaw as global temperatures rise and are releasing increasing amounts of methane. Another hypothesis points to increased production of methane by microbes as the permafrost warms. Currently most observations of greenhouse gases are limited to in-situ (surface and tower sites) and limited airborne in-situ measurements. Space column density measurements are starting to become available from the GOSAT mission. Although methane survives for a shorter time in the atmosphere than CO2, its impact on climate change per molecule is about 23 times than that of CO2. Accurate global observations of several greenhouse gases, including methane, are urgently needed in order to better understand climate change processes and to reduce the uncertainty in the carbon budget. Differential absorption lidar is a well-established technique to measure atmospheric gases, and methane has optical absorption bands near 1.65,2.2,3.4 and 7.8 micron. The near infrared overtones lines of CH4 near 1650 nm are relatively free of interference from other species. There are absorption lines near 1651 nm which are both temperature insensitive and have line strengths well suited for lidar measurements. We have developed a laser and demonstrated lidar measurements of CH4 using lines in this band. Our laser uses a narrow linewidth 1064 nm laser pulse passing through a nonlinear crystal. We generate the tunable laser signals near 1651 nm by using the optical parametric amplification (OPA) process. Inside the crystal the 1064 nm beam overlaps with an injection seed

  11. A Comprehensive Program for Measurements of Military Aircraft Emissions

    DTIC Science & Technology

    2009-11-30

    XRF X - Ray Fluorescence x LIST OF KEYWORDS Air Toxics Engine Emission Extractive Sampling Fastscan...TEFLO® for particulate metal content by X - Ray Fluorescence ( XRF ), while the other set of filters are quartz for measurement of particulate carbon...Particulate sulfur was analyzed after the campaign in a laboratory by using an X - Ray fluorescence ( XRF ) spectrometer on particles collected on

  12. A Comparison of Modeled Pollutant Profiles With MOZAIC Aircraft Measurements

    EPA Science Inventory

    In this study, we use measurements performed under the MOZAIC program to evaluate vertical profiles of meteorological parameters, CO, and ozone that were simulated for the year 2006 with several versions of the WRF/CMAQ modeling system. Model updates, including WRF nudging strate...

  13. ESCOMPTE experiment: intercomparison of four aircraft dynamical, thermodynamical, radiation and chemical measurements

    NASA Astrophysics Data System (ADS)

    Saïd, F.; Corsmeier, U.; Kalthoff, N.; Kottmeier, C.; Lothon, M.; Wieser, A.; Hofherr, T.; Perros, P.

    2005-03-01

    Among seven airplanes involved in the Experience sur Site pour COntraindre les Modèles de Pollution atmosphérique et de Transport d'Emission (ESCOMPTE) experiment in 2001, four measured classical meteorological parameters, radiation fluxes, trace gases and turbulence (for three among four): the Dornier 128 from the Institut für Meteorologie und Klimaforschung, the Fokker 27 ARAT from the Institut National des Sciences de l'Univers, the Merlin 4 and Piper Aztec 23 from Météo France. This paper presents the results of intercomparison flights between three pairs of aircraft. The results are very similar for mean parameters except for the horizontal wind measurements provided by the Merlin that showed a problem that is probably linked to the measurement of the aircraft velocity. Further investigation is required to know whether corrections are possible or not for these wind measurements. Turbulence is studied along two legs over a flat and homogeneous area: in spite of the heterogeneity of the measured functions (one leg is close to the top of the boundary layer), the comparison is rather good. The relative accuracy of the data provided to the data base is given. It easily allows to use the huge amount of aircraft data collected during the experiment with very few restrictions. We underline some points where efforts should be borne for future experiments: wind coupling between Inertial Navigation System data and Global Positioning System (GPS) data, CO and NO x measurements.

  14. Rapid Measurement of Emissions From Military Aircraft Turbine Engines by Downstream Extractive Sampling of Aircraft on the Ground: Results for C-130 and F-15 Aircraft (POSTPRINT)

    DTIC Science & Technology

    2009-02-01

    engines were tested using indoor engine test facilities (F110, F101, J85 -GE-5M, PT6A-68, TF41-A2, TF30-P103 and TF30- P109), while others were studied while...afterburning). Engine T56-A-15 F100-PW-100 F110 F101 J85 -GE-5M PT6A-68 TF-39-1C CFM-56-3 TF41-A2 TF30-P103 TF30-P109 Misc. Type Turboprop Turbofan...AIRCRAFT TURBINE ENGINES BY DOWNSTREAM EXTRACTIVE SAMPLING OF AIRCRAFT ON THE GROUND: RESULTS FOR C-130 AND F-15 AIRCRAFT Chester Spicer and

  15. Comparison of Profiling Microwave Radiometer, Aircraft, and Radiosonde Measurements From the Alliance Icing Research Study (AIRS)

    NASA Technical Reports Server (NTRS)

    Reehorst, Andrew L.

    2001-01-01

    Measurements from a profiling microwave radiometer are compared to measurements from a research aircraft and radiosondes. Data compared is temperature, water vapor, and liquid water profiles. Data was gathered at the Alliance Icing Research Study (AIRS) at Mirabel Airport outside Montreal, Canada during December 1999 and January 2000. All radiometer measurements were found to lose accuracy when the radome was wet. When the radome was not wetted, the radiometer was seen to indicate an inverted distribution of liquid water within a cloud. When the radiometer measurements were made at 15 deg. instead of the standard zenith, the measurements were less accurate.

  16. Statistical Analysis of Elevated Radium and Gross Alpha Measurement in the Sanitary Landfill

    SciTech Connect

    TUCKFIELD, RICHARD

    2004-04-12

    In 2002, radium 226 and 228 measurements elevated above the 5 pCi/L groundwater protection standard (GWPS) and gross alpha measurements above the 15 pCi/L GWPS were noticed in several groundwater monitoring wells at the SRS Sanitary Landfill. An additional four quarters of confirmatory measurements for Ra in the SLF groundwater were taken during 2003 as directed by the SC Department of Health and Environmental Control. Elevated radium concentrations in groundwater of the Aiken County area are a common occurrence. Price and Michel (1990) compiled radium concentrations in drinking water wells of this area and showed several instances of the concentrations exceeding the regulatory limit. Ra226 is an alpha emitter and contributes much of the natural alpha radioactivity found in uncontaminated groundwater. Thus, the elevated radium concentrations are usually accompanied by elevated gross alpha concentrations. Appendix A2 indicates that this is the case at the SLF where Ra226 accounts for almost all elevated gross alpha.

  17. Damage detection in aircraft structures using dynamically measured static flexibility matrices

    SciTech Connect

    Robinson, N.A.; Peterson, L.D.; James, G.H.; Doebling, S.W.

    1996-02-01

    Two methods for detecting the location of structural damage in an aircraft fuselage using modal test data are presented. Both methods use the dynamically measured static flexibility matrix, which is assembled from a combination of measured modal vectors, frequencies, and driving point residual flexibilities. As a consequence, neither method requires a mode-to-mode correlation, and both avoid tedious modal discrimination and selection. The first method detects damage as a softening in the point flexibility components, which are the diagonal entries in the flexibility matrix. The second method detects damage from the disassembled elemental stiffnesses as determined using a presumed connectivity. Vibration data from a laser vibrometer is used to measure the modal mechanics of a DC9 aircraft fuselage before and after induced weakening in a longitudinal stringer. Both methods are shown to detect the location of the damage, primarily because the normal stiffness of the reinforced shell of the fuselage is localized to a few square centimeters.

  18. First lidar measurements of water vapor and aerosols from a high-altitude aircraft

    NASA Technical Reports Server (NTRS)

    Browell, Edward V.; Ismail, Syed

    1995-01-01

    Water vapor plays an important role in many atmospheric processes related to radiation, climate change, atmospheric dynamics, meteorology, the global hydrologic cycle, and atmospheric chemistry, and yet our knowledge of the global distribution of water vapor is very limited. The differential absorption lidar (DIAL) technique has the potential of providing needed high resolution water vapor measurements from aircraft and from space, and the Lidar Atmospheric Sensing Experiment (LASE) is a key step in the development of this capability. The LASE instrument is the first fully engineered, autonomous DIAL system, and it is designed to operate from a high-altitude aircraft (ER-2) and to make water vapor and aerosol profile measurements across the troposphere. The LASE system was flown from the NASA Wallops Flight Facility in a series of engineering flights during September 1994. This paper discusses the characteristics of the LASE system and presents the first LASE measurements of water vapor and aerosol profiles.

  19. Thermodynamic correction of particle concentrations measured by underwing probes on fast-flying aircraft

    NASA Astrophysics Data System (ADS)

    Weigel, Ralf; Spichtinger, Peter; Mahnke, Christoph; Klingebiel, Marcus; Afchine, Armin; Petzold, Andreas; Krämer, Martina; Costa, Anja; Molleker, Sergej; Reutter, Philipp; Szakáll, Miklós; Port, Max; Grulich, Lucas; Jurkat, Tina; Minikin, Andreas; Borrmann, Stephan

    2016-10-01

    Particle concentration measurements with underwing probes on aircraft are impacted by air compression upstream of the instrument body as a function of flight velocity. In particular, for fast-flying aircraft the necessity arises to account for compression of the air sample volume. Hence, a correction procedure is needed to invert measured particle number concentrations to ambient conditions that is commonly applicable to different instruments to gain comparable results. In the compression region where the detection of particles occurs (i.e. under factual measurement conditions), pressure and temperature of the air sample are increased compared to ambient (undisturbed) conditions in certain distance away from the aircraft. Conventional procedures for scaling the measured number densities to ambient conditions presume that the air volume probed per time interval is determined by the aircraft speed (true air speed, TAS). However, particle imaging instruments equipped with pitot tubes measuring the probe air speed (PAS) of each underwing probe reveal PAS values systematically below those of the TAS. We conclude that the deviation between PAS and TAS is mainly caused by the compression of the probed air sample. From measurements during two missions in 2014 with the German Gulfstream G-550 (HALO - High Altitude LOng range) research aircraft we develop a procedure to correct the measured particle concentration to ambient conditions using a thermodynamic approach. With the provided equation, the corresponding concentration correction factor ξ is applicable to the high-frequency measurements of the underwing probes, each of which is equipped with its own air speed sensor (e.g. a pitot tube). ξ values of 1 to 0.85 are calculated for air speeds (i.e. TAS) between 60 and 250 m s-1. For different instruments at individual wing position the calculated ξ values exhibit strong consistency, which allows for a parameterisation of ξ as a function of TAS for the current HALO

  20. Measurement and Simulation of Volatile Particle Emissions from Military Aircraft

    DTIC Science & Technology

    2011-12-01

    HCs and Sulfate • Combustor system studies 0 1 km Carnegie Mellon University Team (WP-1626) • Measurement of PM in engine exhaust • Aging in “ smog ...Stratotanker CFM56-2B Engine Rake Inlet Heated Transfer Line Mobile Laboratory Smog Chamber WP-1626 Engine 1 m DR ~ 1 T ~ 500°C 250 m DR ~ 200 0 2 4 6 8...Dilution sampler, thermodenuder, and smog chamber techniques ● Archival Papers: 7 published, 4 near submission, others in process 25 Primary PM

  1. Aircraft measurements of electrified clouds at Kennedy Space Center

    NASA Technical Reports Server (NTRS)

    Jones, J. J.; Winn, W. P.; Hunyady, S. J.; Moore, C. B.; Bullock, J. W.

    1990-01-01

    The space-vehicle launch commit criteria for weather and atmospheric electrical conditions in us at Cape Canaveral Air Force Station and Kennedy Space Center (KSC) have been made restrictive because of the past difficulties that have arisen when space vehicles have triggered lightning discharge after their launch during cloudy weather. With the present ground-base instrumentation and our limited knowledge of cloud electrification process over this region of Florida, it has not been possible to provide a quantitative index of safe launching conditions. During the fall of 1988, a Schweizer 845 airplane equipped to measure electric field and other meteorological parameters flew over KSC in a program to study clouds defined in the existing launch restriction criteria. All aspects of this program are addressed including planning, method, and results. A case study on the November 4, 1988 flight is also presented.

  2. Surface Acoustic Wave Vibration Sensors for Measuring Aircraft Flutter

    NASA Technical Reports Server (NTRS)

    Wilson, William C.; Moore, Jason P.; Juarez, Peter D.

    2016-01-01

    Under NASA's Advanced Air Vehicles Program the Advanced Air Transport Technology (AATT) Project is investigating flutter effects on aeroelastic wings. To support that work a new method for measuring vibrations due to flutter has been developed. The method employs low power Surface Acoustic Wave (SAW) sensors. To demonstrate the ability of the SAW sensor to detect flutter vibrations the sensors were attached to a Carbon fiber-reinforced polymer (CFRP) composite panel which was vibrated at six frequencies from 1Hz to 50Hz. The SAW data was compared to accelerometer data and was found to resemble sine waves and match each other closely. The SAW module design and results from the tests are presented here.

  3. Measurement of Wideband FM-CW-Radar Characteristics During Approach of Aircraft

    NASA Astrophysics Data System (ADS)

    Küllmer, A.; Spieker, H.; Schüür, J.; Ender, A.

    2012-05-01

    In this paper a method to measure and characterize wideband fm-cw-radars like the radio altimeter of aircraft is presented. The limitations of frequency domain measuring systems will be shown by comparing the results from frequency and time domain based measurements. The need of additional measuring equipment like a down converter and amplifier to improve the signal quality in time domain is described as well as the used software tools to calculate the spectrum. Finally it is described how the frequency ramp speed and shape of the frequency modulated signal can be determined in addition to the already calculated occupied bandwidth and spectral power density.

  4. Aircraft-Based Measurements of Point Source Methane Emissions in the Barnett Shale Basin.

    PubMed

    Lavoie, Tegan N; Shepson, Paul B; Cambaliza, Maria O L; Stirm, Brian H; Karion, Anna; Sweeney, Colm; Yacovitch, Tara I; Herndon, Scott C; Lan, Xin; Lyon, David

    2015-07-07

    We report measurements of methane (CH4) emission rates observed at eight different high-emitting point sources in the Barnett Shale, Texas, using aircraft-based methods performed as part of the Barnett Coordinated Campaign. We quantified CH4 emission rates from four gas processing plants, one compressor station, and three landfills during five flights conducted in October 2013. Results are compared to other aircraft- and surface-based measurements of the same facilities, and to estimates based on a national study of gathering and processing facilities emissions and 2013 annual average emissions reported to the U.S. EPA Greenhouse Gas Reporting Program (GHGRP). For the eight sources, CH4 emission measurements from the aircraft-based mass balance approach were a factor of 3.2-5.8 greater than the GHGRP-based estimates. Summed emissions totaled 7022 ± 2000 kg hr(-1), roughly 9% of the entire basin-wide CH4 emissions estimated from regional mass balance flights during the campaign. Emission measurements from five natural gas management facilities were 1.2-4.6 times larger than emissions based on the national study. Results from this study were used to represent "super-emitters" in a newly formulated Barnett Shale Inventory, demonstrating the importance of targeted sampling of "super-emitters" that may be missed by random sampling of a subset of the total.

  5. Temperature-compensated strain measurement of full-scale small aircraft wing structure using low-cost FBG interrogator

    NASA Astrophysics Data System (ADS)

    Kim, J. H.; Lee, Y. G.; Park, Y.; Kim, C. G.

    2013-04-01

    Recently, health and usage monitoring systems (HUMS) are being studied to monitor the real-time condition of aircrafts during flight. HUMSs can prevent aircraft accidents and reduce inspection time and cost. Fiber Bragg grating (FBG) sensors are widely used for aircraft HUMSs with many advantages such as light weight, small size, easy-multiplexing, and EMI immunity. However, commercial FBG interrogators are too expensive to apply for small aircrafts. Generally the cost of conventional FBG interrogators is over 20,000. Therefore, cost-effective FBG interrogation systems need to be developed for small aircraft HUMSs. In this study, cost-effective low speed FBG interrogator was applied to full-scale small aircraft wing structure to examine the operational applicability of the low speed FBG interrogator to the monitoring of small aircrafts. The cost of the developed low speed FBG interrogator was about 10,000, which is an affordable price for a small aircraft. 10 FBG strain sensors and 1 FBG temperature sensor were installed on the surface of the full-scale wing structure. Load was applied to the tip of the wing structure, and the low speed interrogator detected the change in the center wavelength of the FBG sensors at the sampling rate of 10Hz. To assess the applicability of the low-cost FBG interrogator to full-scale small aircraft wing structure, a temperature-compensated strain measurement algorithm was verified experimentally under various loading conditions of the wing structure with temperature variations.

  6. Aircraft measurements over Fennoscandia during the MAMM project - highlights from 2012-2014

    NASA Astrophysics Data System (ADS)

    Allen, Grant

    2015-04-01

    This paper will present highlights and conclusions from a 3-year campaign of summer airborne measurements across the Fennoscandian region and over the Barents Sea and Svalbard during the Methane in the Arctic Measurements and Modelling (MAMM) campaign. Beginning in July 2012, the UK Facility for Airborne Atmospheric Measurement (FAAM) Bae-146 Atmospheric Research Aircraft has conducted more than 150 hours of sampling over this Arctic domain in a series of tailored process-driven case studies in the period July to September in each year between 2012 and 2014. High precision, continuous measurements of methane concentration and its isotopologues were collected on the FAAM aircraft along with measurements of a wide range of other gases (such as CO2, N2O, O3, CO, HCOOH), aerosol, and thermodynamic parameters. Together, such measurements provide a dataset from which to assess physico-chemical airmass history and specific local and regional emission processes. The FAAM platform complemented a longer term ground-based measurement deployment to collect data for measurement-led case studies, and regional and global model evaluation. In this study we will present highlights from case studies of regionally-averaged snapshots of Arctic wetland methane and formic acid net surface flux and we will present conclusions from airborne methane measurements over potential gas seepage areas on the continental shelf off the coast of Svalbard. We will also present the first airborne remote sensing measurements of methane over the region from the FAAM aircraft and we will present a summer climatology of greenhouse measurements across the MAMM campaign. We will conclude by discussing the next steps in completing the Arctic methane picture and what this might mean for the global methane conundrum.

  7. In-flight measurements of cruise altitude nitric oxide emission indices of commercial jet aircraft

    NASA Astrophysics Data System (ADS)

    Schulte, P.; Schlager, H.

    Simultaneous in-situ NO and CO2 measurements on board the DLR Falcon research aircraft in the exhaust plumes of commercial short to medium range jet aircraft are used to determine lower limits for the NOx emission indices EI(NOx) for cruising conditions. Concentration enhancements for NO and CO2 of 9 to 33 ppbv and 4 to 14 ppmv, respectively, relative to ambient background concentrations were observed in the exhaust trails 40 s to 130 s after emission. The derived EI(NOx)-limits range between 6.4 to 11.7 g/kg. Though the NO2 fraction in the exhaust plumes has not been measured during these pilot investigations, arguments are given that the derived lower limits represent a close approximation to the EI(NOx) values. Within the present uncertainties they are in agreement with predictions based on ground-based engine test data.

  8. Rocket- and aircraft-borne trace gas measurements in the winter polar stratosphere

    NASA Technical Reports Server (NTRS)

    Arnold, F.; Moehler, O.; Pfeilsticker, K.; Ziereis, H.

    1988-01-01

    In January and February 1987 stratospheric rocket- and aircraft-borne trace gas measurements were done in the North Polar region using ACIMS (Active Chemical Ionization Mass Spectrometry) and PACIMS (PAssive Chemical Ionization Mass Spectrometry) instruments. The rocket was launched at ESRANGE (European Sounding Rocket Launching Range) (68 N, 21 E, Northern Sweden) and the twin-jet research aircraft operated by the DFVLR (Deutsche Forschungs- und Versuchs-anstalt fuer Luft- und Raumfahrt), and equipped with a mass spectrometer laboratory was stationed at Kiruna airport. Various stratospheric trace gases were measured including nitric acid, sulfuric acid, non-methane hydrocarbons (acetone, hydrogen cyanide, acetonitrile, methanol etc.), and ambient cluster ions. The experimental data is presented and possible implications for polar stratospheric ozone discussed.

  9. A Low LET Radiation Spectrometer for Measuring Particle Doses in Space and Aircraft

    NASA Technical Reports Server (NTRS)

    Stassinopoulos, E. G.; Stauffer, C. A.; Brucker, G. J.; Dachev, T. P.; Day, John H. (Technical Monitor)

    2002-01-01

    This paper presents experimental data that demonstrates the feasibility of fabricating a miniature nuclear particle dosimeter for monitoring doses in aircraft and satellites. The basic instrument is a Low Linear-Energy-Transfer (LET) Radiation Spectrometer (LoLRS) that is designed to measure the energy deposited by particles with low LET values. The heart of the instrument is a Silicon-Lithium Drifted Diode (SLDD). Test results show that the LoLRS can be used to monitor the radiation threat to personnel in flights of space- and aircraft and also to generate a comprehensive data base from aviation and satellite measurements that can contribute to the formulation of more accurate environmental radiation models for dose predictions with reduced uncertainty factors.

  10. Radiometric gains of satellite sensors of reflected solar radiation - Results from NASA ER-2 aircraft measurements

    NASA Technical Reports Server (NTRS)

    Abel, Peter; Galimore, Reginald; Cooper, John

    1992-01-01

    A method for using congruent aircraft-satellite observations to calibrate a satellite sensor is presented. A calibrated spectroradiometer at an altitude of 19 km above White Sands, NM, is oriented to view White Sands at the satellite overpass time along the same view vector as the satellite sensor. Collected data are transformed into corresponding estimates of sensor band radiance at the satellite (derived from the aircraft measurements), and average count (from the sensor measurements). These are both averaged across the footprint of the spectroradiometer. Results are presented for the evolution of NOAA-11 Advanced Very High Resolution Radiometer (AVHRR) (Bands 1 and 2) gain between November 1988 and October 1990, and for GOES-6 and GOES-7 VISSR/VAS visible bands during the same period. Estimates of uncertainty in the results are presented, as well as ideas for their reduction in future flights.

  11. Measurements of Long-Lived Trace Gases from Commercial Aircraft Platforms: Development of Instrumentation

    NASA Technical Reports Server (NTRS)

    2002-01-01

    The upper troposphere (6-12 km altitude) is a poorly understood and highly vulnerable region of the atmosphere. It is important because many trace species, including ozone, have their greatest impact as greenhouse (infrared-absorbing) gases in this region. The addition of relatively small amounts of anthropogenic chemicals, such as nitrogen oxides, can have a dramatic effect on the abundance of ozone. Some of these pollutants are deposited directly, e.g., by aircraft, while others are transported in. The primary goal of this project was to measure several chemical compounds in the upper troposphere that will help us to understand how air is to transported to that part of the atmosphere; that is, does it come down from the stratosphere, does it rise from the surface via convection, and so on. To obtain adequate sampling to accomplish this goal, we proposed to make measurements from revenue aircraft during normal flight operations.

  12. Measurements of nitrous acid in commercial aircraft exhaust at the Alternative Aviation Fuel Experiment.

    PubMed

    Lee, Ben H; Santoni, Gregory W; Wood, Ezra C; Herndon, Scott C; Miake-Lye, Richard C; Zahniser, Mark S; Wofsy, Steven C; Munger, J William

    2011-09-15

    The Alternative Aviation Fuel Experiment (AAFEX), conducted in January of 2009 in Palmdale, California, quantified aerosol and gaseous emissions from a DC-8 aircraft equipped with CFM56-2C1 engines using both traditional and synthetic fuels. This study examines the emissions of nitrous acid (HONO) and nitrogen oxides (NO(x) = NO + NO(2)) measured 145 m behind the grounded aircraft. The fuel-based emission index (EI) for HONO increases approximately 6-fold from idle to takeoff conditions but plateaus between 65 and 100% of maximum rated engine thrust, while the EI for NO(x) increases continuously. At high engine power, NO(x) EI is greater when combusting traditional (JP-8) rather than Fischer-Tropsch fuels, while HONO exhibits the opposite trend. Additionally, hydrogen peroxide (H(2)O(2)) was identified in exhaust plumes emitted only during engine idle. Chemical reactions responsible for emissions and comparison to previous measurement studies are discussed.

  13. A new measurement method for separating airborne and structureborne noise radiated by aircraft type panels

    NASA Technical Reports Server (NTRS)

    Mcgary, M. C.

    1982-01-01

    The theoretical basis for and experimental validation of a measurement method for separating airborne and structure borne noise radiated by aircraft type panels are presented. An extension of the two microphone, cross spectral, acoustic intensity method combined with existing theory of sound radiation of thin shell structures of various designs, is restricted to the frequency range below the coincidence frequency of the structure. Consequently, the method lends itself to low frequency noise problems such as propeller harmonics. Both an aluminum sheet and two built up aircraft panel designs (two aluminum panels with frames and stringers) with and without added damping were measured. Results indicate that the method is quick, reliable, inexpensive, and can be applied to thin shell structures of various designs.

  14. The IAGOS Information System: From the aircraft measurements to the users.

    NASA Astrophysics Data System (ADS)

    Boulanger, Damien; Thouret, Valérie; Cammas, Jean-Pierre; Petzold, Andreas; Volz-Thomas, Andreas; Gerbig, Christoph; Brenninkmeijer, Carl A. M.

    2013-04-01

    IAGOS (In-service Aircraft for a Global Observing System, http://www.iagos.org) aims at the provision of long-term, frequent, regular, accurate, and spatially resolved in-situ observations of atmospheric chemical composition throughout the troposphere and in the UTLS. It builds on almost 20 years of scientific and technological expertise gained in the research projects MOZAIC (Measurement of Ozone and Water Vapour on Airbus In-service Aircraft) and CARIBIC (Civil Aircraft for the Regular Investigation of the Atmosphere Based on an Instrument Container). The European consortium includes research centres, universities, national weather services, airline operators and aviation industry. IAGOS consists of two complementary building blocks proving a unique global observation system: IAGOS-CORE deploys newly developed instrumentation for regular in-situ measurements of atmospheric chemical species both reactive and greenhouse gases (O3, CO, NOx, NOy, H2O, CO2, CH4), aerosols and cloud particles. In IAGOS-CARIBIC a cargo container is deployed monthly as a flying laboratory aboard one aircraft. Involved airlines ensure global operation of the network. Today, 5 aircraft are flying with the MOZAIC (3) or IAGOS-CORE (2) instrumentation namely 3 aircraft from Lufthansa, 1 from Air Namibia, and 1 from China Airlines Taiwan. A main improvement and new aspect of the IAGOS-CORE instrumentation compared to MOZAIC is to deliver the raw data in near real time (i.e. as soon as the aircraft lands data are transmitted). After a first and quick validation of the O3 and CO measurements, preliminary data are made available in the central database for both the MACC project (Monitoring Atmospheric Composition and Climate) and scientific research groups. In addition to recorded measurements, the database also contains added-value products such as meteorological information (tropopause height, air mass backtrajectories) and lagrangian model outputs (FLEXPART). Data access is handled by open

  15. Hot-wire anemometry for in-flight measurement of aircraft wake vortices

    NASA Technical Reports Server (NTRS)

    Jacobsen, R. A.

    1974-01-01

    An airborne hot-wire anemometry system capable of providing data concerning the vortex structure in the wake of a preceding aircraft has been used in several flight studies. The design features of this technique and the operational experience with it are described. This development program has resulted in a flight-test technique that can make accurate velocity measurements in flow regimes where large velocity gradients occur.

  16. Aerosol Formation In The Free Troposphere: Aircraft and Laboratory Measurements of Ionic and Gaseous Aerosol Precursors

    NASA Astrophysics Data System (ADS)

    Arnold, F.

    Aerosol formation seems to be very efficient in the upper troposphere (UT) as in- dicated by the frequent presence of numerous very small and therefore very young aerosol particles. Aersosol formation proceeds via nucleation of supersaturated low volatility trace gases (LVG) involving either a homogeneous (HONU) or an ion- induced (INU) mechanism. LVG experience rapid removal by condenstation on prefer- ably pre-existing aerosol particles and therefore LVG must be formed locally in the UT by photochemical conversion of precursor gases. A prominent example is gaseous sulfuric acid which is formed from SO2. This SO2 originates at least in the northern hemisphere mostly from fossil fuel combustion at ground-level and to some part origi- nates also from jet aircraft cruising in the UT. Other conceivable LVG's are low volatil- ity organic compounds. After formation by nucleation new particles may experience condensational growth involving LVG. Alternatively new particles may experience scavenging by attachment to pre-existing larger particles. The LVG-concentration has a strong influence on the growth-rate of new particles and thereby on the possibil- ity for growth to the size of a cloud condensation nucleus. Unfortunately present knowledge on free tropospheric LVG is rather poor. Here will be reported free tropo- spheric aircraft-based measurements of ionic and gaseous aerosol-precursors. These include both measurements in the "background" FT as well as measurements in ex- haust plumes of jet aircraft cruising in the UT. Furthermore accompanying new labo- ratory investigations of INU and measurements behind aircraft jet engines at ground- level will also be adressed.

  17. Methane and Other Greenhouse Gas Measurements from Aircraft in Alaska: 2009 - 2011

    NASA Astrophysics Data System (ADS)

    Karion, A.; Sweeney, C.; Wolter, S.; Patrick, L.; Newberger, T.; Chen, H.; Oltmans, S. J.; Bruhwiler, L.; Miller, C. E.; Dlugokencky, E. J.; Tans, P. P.

    2011-12-01

    Due to their huge potential impact on the Earth's warming, methane (CH4) emissions in the Arctic are currently widely-studied and debated in the carbon cycle community. Emissions from carbon stored in Arctic soil are projected to increase as the region warms and the permafrost thaws, creating a potent feedback mechanism for climate change. This year, NASA's Carbon in Arctic Reservoirs Vulnerability Experiment (CARVE) began multi-year aircraft measurements in Alaska, which, coupled with regional modeling of methane fluxes, will evaluate and quantify the effect of regional climate change on ecosystem CO2 and CH4 fluxes. A crucial component of such regional modeling is the choice of background mixing ratio for a given atmospheric sample. A recent addition to the NOAA/GMD aircraft program provides valuable information on background mixing ratios for the Alaskan interior and provides insight into the seasonal cycle and inter-annual variability as well as spatial and temporal context for the measurements being made during the CARVE campaigns. The NOAA/GMD aircraft program began new, ongoing greenhouse gas measurements in Alaska in 2009 (complementing existing ground stations at Barrow and Cold Bay, and a flask-only aircraft site outside of Fairbanks), through a collaboration with the U.S. Coast Guard. Bi-weekly Arctic Domain Awareness flights on C-130 aircraft generally begin in Kodiak, continue to Barrow, and return back to Kodiak after altitude profiles over Kivalina and Galena. On-board measurements include continuous CO2, CH4, CO, and ozone, as well as 24 flask samples analyzed at NOAA for CO2, CH4, CO, and 50 additional gases. In addition to spanning a large geographic region, the measurements also span the entire growing season, from late March to late November each year. We will present data from 2009 - 2011, with a focus on Arctic CH4. The measurements provide us with additional understanding of the various influences on the seasonal cycles of CH4 and CO2

  18. New off-line aircraft instrumentation for non-methane hydrocarbon measurements.

    PubMed

    Bechara, Joelle; Borbon, Agnès; Jambert, Corinne; Perros, Pascal E

    2008-11-01

    New off-line instrumentation was developed to implement measurements of non-methane hydrocarbons (NMHC) on (French) research aircraft. NMHC are collected on multisorbent tubes by AMOVOC (Airborne Measurements Of Volatile Organic Compounds), a new automatic sampler. AMOVOC is a versatile and portable sampler targeting a wide range of NMHC at high frequency (sampling time of 10 min). Multisorbent tubes are analyzed on the ground by short-path thermal desorption coupled with gas chromatography and mass spectrometry. The development and optimization of both NMHC sampling and analysis are reported here. On the one hand, the paper points out technical choices that were made according to aircraft constraints and avoiding sample loss or contamination. On the other hand, it describes analytical optimization, tube storage stability, and moisture removal. The method shows high selectivity, sensitivity (limit of detection less than 10 ppt) and precision (less than 24%). Finally, NMHC data collected on French aircraft during the African Monsoon Multidisciplinary Analysis campaign are reported for the first time. The results highlight instrumentation validity and protocol efficiency for NMHC measurements in the lower and upper troposphere.

  19. Methane and nitrous oxide measurements onboard the UK Atmospheric Research Aircraft using quantum cascade laser spectrometry (QCL)

    NASA Astrophysics Data System (ADS)

    Muller, J. B.; O'Shea, S.; Dorsey, J.; Bauguitte, S.; Cain, M.; Allen, G.; Percival, C. J.; Gallagher, M. W.

    2012-12-01

    A Aerodyne Research© Mini-Quantum Cascade Laser (QCL) spectrometer was installed on the UK Facility of Airborne Atmospheric Measurements (FAAM) BAe-146 research aircraft and employed during summer 2012. Methane (CH4) and nitrous oxide (N2O) concentrations were measured within the Arctic Circle as part of the MAMM project (Methane and other greenhouse gases in the Arctic - Measurements, process studies and Modelling) as well as around the UK as part of the ClearfLo project (Clean Air for London). A range of missions were flown, including deep vertical profiles up to the stratosphere, providing concentration profiles of CH4 and N2O, as well as low altitude level runs exploring near surface diffuse emission sources such as the wetlands in Arctic Lapland and point emissions sources such as gas platforms off the UK coast. Significant pollution plumes were observed both in the Arctic and around the UK with elevated CH4 concentrations, as well as enhanced CO, O3 and aerosol levels. The NAME Lagrangian particle dispersion model will be used to investigate the origins of these CH4 plumes to identify the locations of the emissions sources. The first set of flights using QCL on the FAAM research aircraft have been successful and regular in-flight calibrations (high/low span) and target concentrations were used to determine instrument accuracy and precision. Additional data quality control checks could be made by comparison with an onboard Los Gatos Fast Greenhouse Gas Analyser (FGGA) for CO2 and CH4 and provide the basis for further instrument development and implementation for future Arctic MAMM flights during spring and summer 2013.

  20. Measurements of Flow Rate and Trajectory of Aircraft Tire-Generated Water Spray

    NASA Technical Reports Server (NTRS)

    Daugherty, Robert H.; Stubbs, Sandy M.

    1987-01-01

    An experimental investigation was conducted at the NASA Langley Research Center to measure the flow rate and trajectory of water spray generated by an aircraft tire operating on a flooded runway. Tests were conducted in the Hydrodynamics Research Facility and made use of a partial airframe and a nose tire from a general aviation aircraft. Nose tires from a commercial transport aircraft were also used. The effects of forward speed, tire load, and water depth on water spray patterns were evaluated by measuring the amount and location of water captured by an array of tubes mounted behind the test tire. Water ejected from the side of the tire footprint had the most significant potential for ingestion into engine inlets. A lateral wake created on the water surface by the rolling tire can dominate the shape of the spray pattern as the distance aft of the tire is increased. Forward speed increased flow rates and moved the spray pattern inboard. Increased tire load caused the spray to become less dense. Near the tire, increased water depths caused flow rates to increase. Tests using a fuselage and partial wing along with the nose gear showed that for certain configurations, wing aerodynamics can cause a concentration of spray above the wing.

  1. Large-scale variability in marine stratocumulus clouds defined from simultaneous aircraft and satellite measurements

    NASA Technical Reports Server (NTRS)

    Albrecht, Bruce A.; Barlow, Roy W.

    1990-01-01

    Satellite images often show significant variations in the structure of marine stratocumulus clouds on scales ranging from 10 to 1000 km. This is illustrated where a GOES West satellite image shows a well-defined variation in cloud structure near 32 N, 122 W on 30 June 1987. Aircraft measurements were made with the UK C-130 and the NCAR Electra on this day as part of the FIRE Marine Stratocumulus Intensive Field Observations (IFO). The mean, turbulent, and the microphysical structure of the clouds sampled in these two areas are compared an an attempt is made to explain the differences in cloud structure. In an attempt to identify any systematic differences between the measurements made with the two aircraft, data were analyzed that were collected on 14 July 1987 with the C-130 and the Electra flying in close formation at an altitude of 250 m. The microphysical and turbulence data are being compared in an attempt to explain the differences in the cloud liquid water content obtained with the two aircraft and the differences in cloud structure shown by the GOES image. In addition, data are being analyzed for three other days during the experiment when coordinated downstream flights were made with the Electra and the C-130.

  2. Calibration of strain-gage installations in aircraft structures for the measurement of flight loads

    NASA Technical Reports Server (NTRS)

    Skopinski, T H; Aiken, William S , Jr; Huston, Wilber B

    1954-01-01

    A general method has been developed for calibrating strain-gage installations in aircraft structures, which permits the measurement in flight of the shear or lift, the bending moment, and the torque or pitching moment on the principal lifting or control surfaces. Although the stress in structural members may not be a simple function of the three loads of interest, a straightforward procedure is given for numerically combining the outputs of several bridges in such a way that the loads may be obtained. Extensions of the basic procedure by means of electrical combination of the strain-gage bridges are described which permit compromises between strain-gage installation time, availability of recording instruments, and data reduction time. The basic principles of strain-gage calibration procedures are illustrated by reference to the data for two aircraft structures of typical construction, one a straight and the other a swept horizontal stabilizer.

  3. Measurements of fuselage skin strains and displacements near a longitudinal lap joint in a pressurized aircraft

    NASA Technical Reports Server (NTRS)

    Phillips, Edward P.; Britt, Vicki O.

    1991-01-01

    Strains and displacements in a small area near a longitudinal lap joint in the fuselage skin of a B737 aircraft were measured during a pressurization cycle to a differential pressure of 6.2 psi while the aircraft was on the ground. It was found that hoop strains were higher than longitudinal strains at each location; membrane strains in the unreinforced skin were higher than in the joint; membrane strains in the hoop direction, as well as radial displacements, tended to be highest at the mid-bay location between skin reinforcements; significant bending in the hoop direction occurred in the joint and in the skin near the joint, and the bending was unsymmetrically distributed about the stringer at the middle of the joint; and radial displacements were unsymmetrically distributed across the lap joint. The interpretation of the strain gage data for locations on the bonded and riveted lap joint assumed that the joint did not contain disbonded areas.

  4. PIV Measurements of Chevrons on F400 Tactical Aircraft Nozzle Model

    NASA Technical Reports Server (NTRS)

    Bridges, James; Wernet, Mark; Frate, Franco

    2010-01-01

    Previous talks at this meeting have covered our collaborative work on high-energy jets such as present in tactical aircraft (those with supersonic plumes). The emphasis of this work is improving our understanding of flow physics and our prediction tools. In this presentation we will discuss recent flow diagnostics acquired using Particle Image Velocimetry (PIV) made on an underexpanded shocked jet plume from a tactical aircraft nozzle. In this presentation we show cross-sectional and streamwise cuts of both mean and turbulent velocities of an F404 engine nozzle with various chevron designs applied. The impact of chevron penetration, length, and width are documented. The impact of the parameters is generally nonlinear in measures considered here, a surprising result given the relatively smooth behavior of the noise to variations in these chevron parameters.

  5. An observer for a velocity-sensorless VTOL aircraft with time-varying measurement delay

    NASA Astrophysics Data System (ADS)

    He, Qing; Liu, Jinkun

    2016-02-01

    This paper presents a kind of state observer for a velocity-sensorless vertical take-off and landing (VTOL) aircraft with bounded time-varying delay in its measurement outputs. The proposed observer predicts current state variables based on the delayed outputs, and the estimated state variables can be considered as the actual state variables for feedback control scheme design. Since the delay is time-varying, compared to the constant delay case, different analysis theory must be employed. Under the assumption that the delays are identical for different outputs and bounded input, the asymptotic convergence property of the estimation error based on Lyapunov-Razumikhin theorem is proved. A relative large time delay for the VTOL aircraft in the outputs has been tested in the numerical simulation, and the simulation results show the effectiveness of the proposed observer.

  6. Estimates of Precipitation Embryo Densities Using Measurements from an Aircraft Radar.

    NASA Astrophysics Data System (ADS)

    Mather, Graeme K.

    1989-10-01

    Determination of the habits (ice or water) and therefore the densities of particles whose images are acquired by 2D probes is often an ambiguous process. A Learjet's radar measurements of equivalent reflectivity factors from a range gate 1800 m ahead of the aircraft are compared to reflectivities calculated from images acquired by a 2D-C probe over a range of assumed particle densities from 0.2 to 1 g cm3. Although the comparisons suffer from many uncertainties, such as the vast disparity between the volumes sampled by the 2D-C probe and the aircraft radar, the method does discriminate well between water drops or recently frozen riming water drops and low density graupel particles.

  7. Trace Gas Measurements made from Aircraft over North America and China

    NASA Astrophysics Data System (ADS)

    Dickerson, R. R.; Marufu, L. T.; Hains, J.; Taubman, B.; Stehr, J.; Li, Z.; Li, C.; Doddridge, B. G.

    2005-12-01

    Trace gases O3, CO, SO2, and aerosol optical properties were measured from a small research aircraft for ten summers over the Mid Atlantic region of the United States. The resultant profiles from the surface to about 3000 m altitude have been analyzed to show the role of long-range transport, boundary layer dynamics, convection, and emissions on concentrations and trends. Large, coal-fired power plants in the Ohio River Valley dominate O3 and SO2 concentrations under anti-cyclonic flow, but the contribution from these electricity generating units appears to have decreased over the past three years and pollutant concentrations have fallen, even when interannual variations in meteorology are removed. The same small aircraft package was flown over NE China last spring, and results are contrasted with those from North America.

  8. Correction of Doppler Rada Data for Aircraft Motion Using Surface Measurements and Recursive Least-Squares Estimation

    NASA Technical Reports Server (NTRS)

    Durden, S.; Haddad, Z.

    1998-01-01

    Observations of Doppler velocity of hydrometeors form airborne Doppler weather radars normally contains a component due to the aircraft motion. Accurate hydrometeor velocity measurements thus require correction by subtracting this velocity from the observed velocity.

  9. A method for measuring vertical accretion, elevation, and compaction of soft, shallow-water sediments

    USGS Publications Warehouse

    Cahoon, D.R.; Marin, P.E.; Black, B.K.; Lynch, J.C.

    2000-01-01

    High-resolution measures of vertical accretion, elevation, and compaction of shallow-water sediments are fundamental to understanding the processes that control elevation change and the mechanisms of progradation (e.g., development of mudflats and intertidal wetlands) in coastal systems. Yet, measurements of elevation by traditional survey methods often are of low accuracy because of the compressible nature of the substrates. Nor do they provide measures of vertical accretion or sediment compaction. This paper evaluates the use in shallow-water systems of an approach designed to measure these variables in vegetated wetlands. The approach employs simultaneous measures of elevation from temporary benchmarks using a sedimentation-erosion table (SET) and vertical accretion from marker horizons with sediment cores collected with a cryogenic coring apparatus. The measures are made with a level of resolution sufficient to distinguish between the influence of surface and subsurface processes on elevation, thus providing quantitative estimates of shallow subsidence. The SET-marker horizon approach was evaluated on a developing splay created by an artificial crevasse of a distributary in the Mississippi River delta. The approach provided high-resolution measures of vertical accretion (48.3 ' 2.0 cm.) and elevation (36.7 ' 1.6 cm) over a 4-year period, with the difference between the two indicating the amount of shallow subsidence. In addition, by laying new marker horizons in later years, the approach provided rates not only of shallow subsidence (3.9 ' 0.5 cm y-1) but also compaction of newly deposited seiments (2.1 ' 0.6 cm y-1) and compaction of underlying sediments (1.8 ' 2.0 cm y-1 ) over a two-year period. Hence, the SET-marker horizon approach has widespread applicability in both emergent wetland and shallow water environments for providing high resolution measures of the processes controlling elevation change.

  10. Imposing strong constraints on tropical terrestrial CO2 fluxes using passenger aircraft based measurements

    NASA Astrophysics Data System (ADS)

    Niwa, Y.; Machida, T.; Sawa, Y.; Matsueda, H.; Schuck, T. J.; Brenninkmeijer, C. A.; Imasu, R.; Satoh, M.

    2011-12-01

    Better understanding of the global and regional carbon budget is needed to perform a reliable prediction of future climate with an earth system model. However, the reliability of CO2 source/sink estimation by inverse modeling, which is one of the promising methods to estimate regional carbon budget, is limited because of sparse observational data coverage. Very few observational data are available in tropics. Therefore, especially the reconstruction of tropical terrestrial fluxes has considerable uncertainties. In this study, regional CO2 fluxes for 2006-2008 are estimated by inverse modeling using the Comprehensive Observation Network for Trace gases by Airliner (CONTRAIL) in addition to the surface measurement dataset of GLOBALVIEW-CO2. CONTRAIL is a recently established CO2 measurement network using in-situ measurement instruments on board commercial aircraft. Five CONTRAIL aircraft travel back and forth between Japan and many areas: Europe, North America, Southeast Asia, South Asia, and Australia. The Bayesian synthesis approach is used to estimate monthly fluxes for 42 regions using NICAM-TM simulations with existing CO2 flux datasets and monthly mean observational data. It is demonstrated that the aircraft data have great impact on estimated tropical terrestrial fluxes. By adding the aircraft data to the surface data, the analyzed uncertainty of tropical fluxes has been reduced by 15 % and more than 30 % uncertainty reduction rate is found in Southeast and South Asia. Specifically, for annual net CO2 fluxes, nearly neutral fluxes of Indonesia, which is estimated using the surface dataset alone, turn to positive fluxes, i.e. carbon sources. In Indonesia, a remarkable carbon release during the severe drought period of October-December in 2006 is estimated, which suggests that biosphere respiration or biomass burning was larger than the prior fluxes. Comparison of the optimized atmospheric CO2 with independent aircraft measurements of CARIBIC tends to validate

  11. AGARD Flight Test Instrumentation Series. Volume 7. Strain Gauge Measurements on Aircraft

    DTIC Science & Technology

    1976-04-01

    Epoxy resin-glass fibre 4 550 650 Asbestos 100 670 700 The values refer to the supporting materials; the limits for the measuring grid materials are...AGARD publications. 13.Keywords/Descriptors 14.UDC Aircraft Flight tests Strain measurement Airborne equipment 620.17:5533.6.054:629.73.05 Loads (forces...3.5.4 A.C. voltage supply 28I 3.6 lImmunity from electrical and magnetic disturbances 29 3.6.1 Common-mode voltages 29 3.6.2 Electrical and magnetic

  12. Measurements of HONO, NO, NOy and SO2 in aircraft exhaust plumes at cruise

    NASA Astrophysics Data System (ADS)

    Jurkat, T.; Voigt, C.; Arnold, F.; Schlager, H.; Kleffmann, J.; Aufmhoff, H.; Schäuble, D.; Schaefer, M.; Schumann, U.

    2011-05-01

    Measurements of gaseous nitrogen and sulfur oxide emissions in young aircraft exhaust plumes give insight into chemical oxidation processes inside aircraft engines. Particularly, the OH-induced formation of nitrous acid (HONO) from nitrogen oxide (NO) and sulfuric acid (H2SO4) from sulfur dioxide (SO2) inside the turbine which is highly uncertain, need detailed analysis to address the climate impact of aviation. We report on airborne in situ measurements at cruise altitudes of HONO, NO, NOy, and SO2 in 9 wakes of 8 different types of modern jet airliners, including for the first time also an A380. Measurements of HONO and SO2 were made with an ITCIMS (Ion Trap Chemical Ionization Mass Spectrometer) using a new ion-reaction scheme involving SF5- reagent ions. The measured molar ratios HONO/NO and HONO/NOy with averages of 0.038 ± 0.010 and 0.027 ± 0.005 were found to decrease systematically with increasing NOx emission-index (EI NOx). We calculate an average EI HONO of 0.31 ± 0.12 g NO2 kg-1. Using reliable measurements of HONO and NOy, which are less adhesive than H2SO4 to the inlet walls, we derive the OH-induced conversion fraction of fuel sulfur to sulfuric acid $\\varepsilon$ with an average of 2.2 ± 0.5 %. $\\varepsilon$ also tends to decrease with increasing EI NOx, consistent with earlier model simulations. The lowest HONO/NO, HONO/NOy and $\\varepsilon$ was observed for the largest passenger aircraft A380.

  13. Aircraft mass budgeting to measure CO2 emissions of Rome, Italy.

    PubMed

    Gioli, Beniamino; Carfora, Maria F; Magliulo, Vincenzo; Metallo, Maria C; Poli, Attilio A; Toscano, Piero; Miglietta, Franco

    2014-04-01

    Aircraft measurements were used to estimate the CO2 emission rates of the city of Rome, assessed against high-resolution inventorial data. Three experimental flights were made, composed of vertical soundings to measure Planetary Boundary Layer (PBL) properties, and circular horizontal transects at various altitudes around the city area. City level emissions and associated uncertainties were computed by means of mass budgeting techniques, obtaining a positive net CO2 flux of 14.7 ± 4.5, 2.5 ± 1.2, and 10.3 ± 1.2 μmol m(-2) s(-1) for the three flights. Inventorial CO2 fluxes at the time of flights were computed by means of spatial and temporal disaggregation of the gross emission inventory, at 10.9 ± 2.5, 9.6 ± 1.3, and 17.4 ± 9.6 μmol m(-2) s(-1). The largest differences between the two dataset are associated with a greater variability of wind speed and direction in the boundary layer during measurements. Uncertainty partitioned into components related to horizontal boundary flows and top surface flow, revealed that the latter dominates total uncertainty in the presence of a wide variability of CO2 concentration in the free troposphere (up to 7 ppm), while it is a minor term with uniform tropospheric concentrations in the study area (within 2 ppm). Overall, we demonstrate how small aircraft may provide city level emission measurements that may integrate and validate emission inventories. Optimal atmospheric conditions and measurement strategies for the deployment of aircraft experimental flights are finally discussed.

  14. An Elevated Reservoir of Air Pollutants over the Mid-Atlantic States During the 2011 DISCOVER-AQ Campaign: Airborne Measurements and Numerical Simulations

    NASA Technical Reports Server (NTRS)

    He, Hao; Loughner, Christopher P.; Stehr, Jeffrey W.; Arkinson, Heather L.; Brent, Lacey C.; Follette-Cook, Melanie B.; Tzortziou, Maria A.; Pickering, Kenneth E.; Thompson, Anne M.; Martins, Douglas K.; Diskin, Glenn S.; Anderson, Bruce E.; Crawford, James H.; Weinheimer, Andrew J.; Lee, Pius; Hains, Jennifer C.; Dickerson, Russell R.

    2013-01-01

    During a classic heat wave with record high temperatures and poor air quality from July 18 to 23, 2011, an elevated reservoir of air pollutants was observed over and downwind of Baltimore, MD, with relatively clean conditions near the surface. Aircraft and ozonesonde measurements detected approximately 120 parts per billion by volume ozone at 800 meters altitude, but approximately 80 parts per billion by volume ozone near the surface. High concentrations of other pollutants were also observed around the ozone peak: approximately 300 parts per billion by volume CO at 1200 meters, approximately 2 parts per billion by volume NO2 at 800 meters, approximately 5 parts per billion by volume SO2 at 600 meters, and strong aerosol optical scattering (2 x 10 (sup 4) per meter) at 600 meters. These results suggest that the elevated reservoir is a mixture of automobile exhaust (high concentrations of O3, CO, and NO2) and power plant emissions (high SO2 and aerosols). Back trajectory calculations show a local stagnation event before the formation of this elevated reservoir. Forward trajectories suggest an influence on downwind air quality, supported by surface ozone observations on the next day over the downwind PA, NJ and NY area. Meteorological observations from aircraft and ozonesondes show a dramatic veering of wind direction from south to north within the lowest 5000 meters, implying that the development of the elevated reservoir was caused in part by the Chesapeake Bay breeze. Based on in situ observations, Community Air Quality Multi-scale Model (CMAQ) forecast simulations with 12 kilometers resolution overestimated surface ozone concentrations and failed to predict this elevated reservoir; however, CMAQ research simulations with 4 kilometers and 1.33 kilometers resolution more successfully reproduced this event. These results show that high resolution is essential for resolving coastal effects and predicting air quality for cities near major bodies of water such as

  15. An elevated reservoir of air pollutants over the Mid-Atlantic States during the 2011 DISCOVER-AQ campaign: Airborne measurements and numerical simulations

    NASA Astrophysics Data System (ADS)

    He, Hao; Loughner, Christopher P.; Stehr, Jeffrey W.; Arkinson, Heather L.; Brent, Lacey C.; Follette-Cook, Melanie B.; Tzortziou, Maria A.; Pickering, Kenneth E.; Thompson, Anne M.; Martins, Douglas K.; Diskin, Glenn S.; Anderson, Bruce E.; Crawford, James H.; Weinheimer, Andrew J.; Lee, Pius; Hains, Jennifer C.; Dickerson, Russell R.

    2014-03-01

    During a classic heat wave with record high temperatures and poor air quality from July 18 to 23, 2011, an elevated reservoir of air pollutants was observed over and downwind of Baltimore, MD, with relatively clean conditions near the surface. Aircraft and ozonesonde measurements detected ˜120 ppbv ozone at 800 m altitude, but ˜80 ppbv ozone near the surface. High concentrations of other pollutants were also observed around the ozone peak: ˜300 ppbv CO at 1200 m, ˜2 ppbv NO2 at 800 m, ˜5 ppbv SO2 at 600 m, and strong aerosol optical scattering (2 × 10-4 m-1) at 600 m. These results suggest that the elevated reservoir is a mixture of automobile exhaust (high concentrations of O3, CO, and NO2) and power plant emissions (high SO2 and aerosols). Back trajectory calculations show a local stagnation event before the formation of this elevated reservoir. Forward trajectories suggest an influence on downwind air quality, supported by surface ozone observations on the next day over the downwind PA, NJ and NY area. Meteorological observations from aircraft and ozonesondes show a dramatic veering of wind direction from south to north within the lowest 5000 m, implying that the development of the elevated reservoir was caused in part by the Chesapeake Bay breeze. Based on in situ observations, CMAQ forecast simulations with 12 km resolution overestimated surface ozone concentrations and failed to predict this elevated reservoir; however, CMAQ research simulations with 4 km and 1.33 km resolution more successfully reproduced this event. These results show that high resolution is essential for resolving coastal effects and predicting air quality for cities near major bodies of water such as Baltimore on the Chesapeake Bay and downwind areas in the Northeast.

  16. New technique for the direct measurement of core noise from aircraft engines

    NASA Technical Reports Server (NTRS)

    Krejsa, E. A.

    1981-01-01

    A new technique is presented for directly measuring the core noise levels from gas turbine aircraft engines. The technique requires that fluctuating pressures be measured in the far-field and at two locations within the engine core. The cross-spectra of these measurements are used to determine the levels of the far-field noise that propagated from the engine core. The technique makes it possible to measure core noise levels even when other noise sources dominate. The technique was applied to signals measured from an AVCO Lycoming YF102 turbofan engine. Core noise levels as a function of frequency and radiation angle were measured and are presented over a range of power settings.

  17. Airborne measurements performed by a light aircraft during Pegasos spring 2013 campaign

    NASA Astrophysics Data System (ADS)

    Väänänen, Riikka; Krejci, Radovan; Manninen, Hanna E.; Nieminen, Tuomo; Yli-Juuti, Taina; Kangasluoma, Juha; Pohja, Toivo; Aalto, Pasi P.; Petäjä, Tuukka; Kulmala, Markku

    2014-05-01

    To fully understand the chemical and physical processes in atmosphere, measuring only on-ground is not sufficient. To extend the measurements into the lower troposphere, the University of Helsinki has performed airborne campaigns since 2009. During spring 2013, a light aircraft was used to measure the aerosol size distribution over boreal forests as a part of the Pegasos 'Norhern Mission'. The aims of the measurements were to quantify the vertical profiles of aerosols up to the altitude of 3.5 km, to study the new particle formation in the lower troposphere, to measure the planetary boundary layer evolution, and to support the measurements performed by Zeppelin NT. We used a Cessna 172 light aircraft as a platform. An aerosol and gas inlet was mounted under the right wing and the sample air was conducted inside the cabin where most of the instruments were placed. The aerosol measurement instruments included a TSI 3776 condensation particle counter (CPC) with a cut-off size of 3 nm, a Scanning Mobility Particle Sizer (SMPS), with a size range of 10-350 nm, and a Particle Size Magnifier (PSM) connected with a TSI 3772 condensation particle counter. As the properties of the PSM measuring in airborne conditions were still under testing during the campaign, the setups of the PSM varied between the measurements. Other instruments on board included a Li-Cor Li-840 H2O/Co2-analyzer, a temperature sensor, a relative humidity sensor, and a GPS receiver. Total amount of 45 flights with 118 flight hours were performed between 24th April and 15th June 2013. The majority of the flights were flown around SMEAR II station located in Hyytiälä, and when possible, the flights were synchronized with the Zeppelin flights. Simultaneously, an extensive field campaign to measure aerosol and gas properties was performed on-ground at SMEAR II station. A time series of airborne aerosol data of around 1.5 months allows us to construct statistical vertical profiles of aerosol size

  18. Two Wavelength Ti:sapphire Laser for Ozone DIAL Measurements from Aircraft

    NASA Technical Reports Server (NTRS)

    Situ, Wen; DeYoung, Russel J.

    1998-01-01

    Laser remote sensing of ozone from aircraft has proven to be a valuable technique for understanding the distribution and dynamics of ozone in the atmosphere. Presently the differential absorption lidar (DIAL) technique, using dual ND:YAG lasers that are doubled to pump dye lasers which in turn are doubled into the UV for the "on" and "off' line lasers, is used on either the NASA DC-8 or P-3 aircraft. Typically, the laser output for each line is 40-mJ and this is split into two beams, one looking up and the other downward, each beam having about 20-mJ. The residual ND:YAG (1.06 micron) and dye laser energies are also transmitted to obtain information on the atmospheric aerosols. While this system has operated well, there are several system characteristics that make the system less than ideal for aircraft operations. The system, which uses separate "on" and "off" line lasers, is quite large and massive requiring valuable aircraft volume and weight. The dye slowly degrades with time requiring replacement. The laser complexity requires a number of technical people to maintain the system performance. There is also the future interest in deploying an ozone DIAL system in an Unpiloted Atmospheric Vehicle (UAV) which would require a total payload mass of less than 150 kg and power requirement of less than 1500 W. A laser technology has emerged that could potentially provide significant enhancements over the present ozone DIAL system. The flashlamp pumped Ti:sapphire laser system is an emerging technology that could reduce the mass and volume over the present system and also provide a system with fewer conversion steps, reducing system complexity. This paper will discuss preliminary results from a flashlamp-pumped Ti:sapphire laser constructed as a radiation source for a UV DIAL system to measure ozone.

  19. An optical particle size spectrometer for aircraft-borne measurements in IAGOS-CARIBIC

    NASA Astrophysics Data System (ADS)

    Hermann, Markus; Weigelt, Andreas; Assmann, Denise; Pfeifer, Sascha; Muller, Thomas; Conrath, Thomas; Voigtlander, Jens; Heintzenberg, Jost; Wiedensohler, Alfred; Martinsson, Bengt G.; Deshler, Terry; Brenninkmeijer, Carl A. M.; Zahn, Andreas

    2016-05-01

    The particle number size distribution is an important parameter to characterize the atmospheric aerosol and its influence on the Earth's climate. Here we describe a new optical particle size spectrometer (OPSS) for measurements of the accumulation mode particle number size distribution in the tropopause region on board a passenger aircraft (IAGOS-CARIBIC observatory: In-service Aircraft for a Global Observing System - Civil Aircraft for Regular Investigation of the Atmosphere Based on an Instrument Container). A modified KS93 particle sensor from RION Co., Ltd., together with a new airflow system and a dedicated data acquisition system, is the key component of the CARIBIC OPSS. The instrument records individual particle pulse signal curves in the particle size range 130-1110 nm diameter (for a particle refractive index of 1.47-i0.006) together with a time stamp and thus allows the post-flight choice of the time resolution and the size distribution bin width. The CARIBIC OPSS has a 50 % particle detection diameter of 152 nm and a maximum asymptotic counting efficiency of 98 %. The instrument's measurement performance shows no pressure dependency and no particle coincidence for free tropospheric conditions. The size response function of the CARIBIC OPSS was obtained by a polystyrene latex calibration in combination with model calculations. Particle number size distributions measured with the new OPSS in the lowermost stratosphere agreed within a factor of 2 in concentration with balloon-borne measurements over western North America. Since June 2010 the CARIBIC OPSS is deployed once per month in the IAGOS-CARIBIC observatory.

  20. The Application of Laser Speckle Interferometry to Measure Strain at Elevated Temperatures and Various Loading Rates

    DTIC Science & Technology

    1990-05-01

    MTL TR 90-23 lAD IAD- A225 583 JILL COPY THE APPLICATION OF LASER SPECKLE INTERFEROMETRY TO MEASURE STRAIN AT ELEVATED TEMPERATURES AND VARIOUS...specimen was visable. Then LSI was used to measure further straining in the necking regions. The second question to be answered was whc:’,- cr LSI

  1. Visible and near-infrared channel calibration of the GOES-6 VISSR using high-altitude aircraft measurements

    NASA Technical Reports Server (NTRS)

    Smith, Gilbert R.; Levin, Robert H.; Koyanagi, Robert S.; Wrigley, Robert C.

    1989-01-01

    Present and future visible and near-infrared wavelength sensors mounted on operational satellites do not have on-board absolute calibration devices. One means of establishing an in-orbit calibration for a satellite sensor is to make simultaneous measurements of a bright, relatively uniform scene along the satellite view vector from a calibrated instrument on board a high altitude aircraft. Aircraft data were recorded over White Sands, New Mexico, and the coincident aircraft and orbiting satellite data is compared for the visible and near-infrared wavelength channel of the GOES-6 Visible Infrared Spin-Scan Radiometer.

  2. Ground-based aircraft exhaust measurements of a Lufthansa Airbus A340 using FTIR emission spectrometry

    NASA Astrophysics Data System (ADS)

    Schaefer, Klaus; Heland, Joerg

    1999-01-01

    The emission inventories of aircraft emissions are being set up using flight routing data and test rig measurements of the engine manufacturers for certification purposes which have to be extrapolated with respect to the actual parameters at cruise altitude. Precise data from in-service engines are not existing. FTIR-emission-spectroscopy as a remote sensing multi-component exhaust gas analysis method has been further developed to specify the traceable molecules in aircraft exhausts, to determine the detection limits, and to obtain reliable statements concerning its accuracy. The first measurement with the Airbus A340 engine CFM56-5C2 during run up tests at ground level showed the overall ability of the FTIR-emission system to analyze the exhausts of modern gas turbines with high bypass ratio and mixing of fan air into the exhausts before the nozzle exit. Good quality spectra were measured and analyzed with respect to the mixing rations of CO2, H2O, CO, NO, and N2O, and the emission indices of CO, NO, and N2O. Total measurement times at one thrust level should be about 15 minutes to obtain reliable result which can be compared to the ICAO data of this engine.

  3. Aircraft measurements of the atmospheric electrical global circuit during the period 1971-1984

    NASA Technical Reports Server (NTRS)

    Markson, R.

    1985-01-01

    This report will update an investigation of the global circuit conducted over the last 14 years through aircraft measurements of the variation of ionospheric potential and associated parameters. The data base included electric field, conductivity, and air-earth current density profiles from the tropics (25 deg N) to the Arctic (79 deg N). Almost all of the data have been obtained over the ocean to reduce noise associated with local generators, aerosols, and convection. Recently, two aircraft have been utilized to obtain, for the first time, quasi-periodic sets of simultaneous ionospheric potential (VI) soundings at remote locations and extending over time spans sufficiently long so that the universal time diurnal variation (Carnegie curve) could be observed. In additon, these measurements provided the first detection of the modulation of electric fields in the troposphere caused by the double vortex ionospheric convection pattern. Besides summarizing these measurements and comparing them to similar data obtained by other groups, this report discusses meteorological sources of error and criteria for determining if the global circuit is being measured rather than variations caused by local meteorological processes.

  4. 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.

  5. Measuring reactive nitrogen emissions from point sources using visible spectroscopy from aircraft.

    PubMed

    Melamed, M L; Solomon, S; Daniel, J S; Langford, A O; Portmann, R W; Ryerson, T B; Nicks, D K; McKeen, S A

    2003-02-01

    Accurate measurements of nitrogen dioxide (NO2), a key trace gas in the formation and destruction of tropospheric ozone, are important in studies of urban pollution. Nitrogen dioxide column abundances were measured during the Texas Air Quality Study 2000 using visible absorption spectroscopy from an aircraft. The method allows for quantification of the integrated total number of nitrogen dioxide molecules in the polluted atmosphere and is hence a useful tool for measuring plumes of this key trace gas. Further, we show how such remote-sensing observations can be used to obtain information on the fluxes of nitrogen dioxide into the atmosphere with unique flexibility in terms of aircraft altitude, and the height and extent of mixing of the boundary layer. Observations of nitrogen dioxide plumes downwind of power plants were used to estimate the flux of nitrogen oxide emitted from several power plants in the Houston and Dallas metropolitan areas and in North Carolina. Measurements taken over the city of Houston were also employed to infer the total flux from the city as a whole.

  6. Aircraft measurements of aerosol properties during GoAmazon - G1 and HALO inter-comparison

    NASA Astrophysics Data System (ADS)

    Mei, F.; Cecchini, M. A.; Wang, J.; Tomlinson, J. M.; Comstock, J. M.; Hubbe, J. M.; Pekour, M. S.; Machado, L.; Wendisch, M.; Longo, K.; Martin, S. T.; Schmid, B.; Weinzierl, B.; Krüger, M. L.; Zöger, M.

    2015-12-01

    Currently, the indirect effects of atmospheric aerosols remain the most uncertain components in forcing of climate change over the industrial period (IPCC, 2013). This large uncertainty is partially a result of our incomplete understanding of the ability of particles to form cloud droplets under atmospherically relevant supersaturations. One objective of the US Department of Energy (DOE) Green Ocean Amazon Project (GoAmazon2014/5) is to understand the influence of the emission from Manaus, a tropical megacity, on aerosol size, concentration, and chemical composition, and their impact on cloud condensation nuclei (CCN) spectrum. The GoAmazon2014/5 study was an international campaign with the collaboration efforts from US, Brazil and Germany. During the intensive operation period, in the dry season (Sep. 1st - Oct. 10th, 2014), aerosol concentration, size distributions, and CCN spectra, both under pristine conditions and inside the Manaus plume, were characterized in-situ from the DOE Gulfstream-1 (G-1) research aircraft and German HALO aircraft during 4 coordinated flights on Sep. 9th, Sep. 16th, Sep 21st and Oct. 1st, 2014. During those four flights, aerosol number concentrations and CCN concentrations at two supersaturations (0.25% and 0.5%) were measured by condensation particle counters (CPCs) and a DMT dual column CCN counter onboard both G-1 and HALO. Aerosol size distribution was also measured by a Fast Integrated Mobility Spectrometer (FIMS) aboard the G-1 and is compared with the size distribution from Ultra High Sensitivity Aerosol Spectrometer - Airborne (UHSAS-A, DMT), which were deployed both on the G-1 and the HALO. Good agreement between the aerosol properties measured from the two aircraft has been achieved. The vertical profiles of aerosol size distribution and CCN spectrum will be discussed.

  7. A Backward Modeling Study of Intercontinental Pollution Transport Using Aircraft Measurements

    NASA Astrophysics Data System (ADS)

    Stohl, A.; Forster, C.; Eckhardt, S.; Huntrieser, H.; Heland, J.; Schlager, H.; Aufmhoff, H.; Arnold, F.; Cooper, O.

    2002-12-01

    In this paper we present simulations with a Lagrangian particle dispersion model to study the intercontinental transport of pollution from North America during an aircraft measurement campaign over Europe. The model was used for both the flight planning and a detailed source analysis after the campaign, which is described here with examples from two episodes. First, forward calculations of emission tracers from North America, Europe and Asia were made to understand the transport processes. Both episodes were preceded by stagnant conditions over North America, leading to the accumulation of pollutants in the North American boundary layer. This pollution was then exported by warm conveyor belts to the middle and upper troposphere, and transported rapidly to Europe. Concentrations of many chemical trace species (CO, NOy, CO2, acetone, and several VOCs; O3 in one case) measured aboard the research aircraft were clearly enhanced in the pollution plumes compared to the conditions outside the plumes. Backward simulations with the particle model were introduced as an indispensable tool for a more detailed analysis of the plume's source region. They make trajectory analyses, which to date were mainly used to interpret aircraft measurement data, obsolete for establishing source-receptor relationships. Using an emission inventory, we could decompose the tracer mixing ratios at the receptors (i.e., along the flight tracks) into contributions from every grid cell of the inventory. For both North America plumes, we found that emission sources contributing to the tracer concentrations over Europe were distributed over large areas in North America. In one case, the region around New York was clearly the largest contributor, but in the other case, sources in California, Texas, and Florida contributed almost equally. Smaller contributions were made by sources reaching from the Yucatan peninsula to Canada in this case.

  8. Spatial and temporal variation in CO over Alberta using measurements from satellites, aircraft, and ground stations

    NASA Astrophysics Data System (ADS)

    Marey, H. S.; Hashisho, Z.; Fu, L.; Gille, J.

    2015-04-01

    Alberta is Canada's largest oil producer, and its oil sands deposits comprise 30% of the world's oil reserves. The process of bitumen extraction and upgrading releases trace gases and aerosols to the atmosphere. In this study we present satellite-based analysis to explore, for the first time, various contributing factors that affect tropospheric carbon monoxide (CO) levels over Alberta. The multispectral product that uses both near-infrared (NIR) and the thermal-infrared (TIR) radiances for CO retrieval from the Measurements of Pollution in the Troposphere (MOPITT) is examined for the 12-year period from 2002 to 2013. The Moderate Resolution Imaging Spectroradiometer (MODIS) thermal anomaly product from 2001 to 2013 is employed to investigate the seasonal and temporal variations in forest fires. Additionally, in situ CO measurements at industrial and urban sites are compared to satellite data. Furthermore, the available MOZAIC/IAGOS (Measurement of Ozone, Water Vapor, Carbon Monoxide, Nitrogen Oxide by Airbus In-Service Aircraft/In service Aircraft for Global Observing System) aircraft CO profiles (April 2009-December 2011) are used to validate MOPITT CO data. The climatological time curtain plot and spatial maps for CO over northern Alberta indicate the signatures of transported CO for two distinct biomass burning seasons: summer and spring. Distinct seasonal patterns of CO at the urban sites (Edmonton and Calgary) point to the strong influence of traffic. Meteorological parameters play an important role in the CO spatial distribution at various pressure levels. Northern Alberta shows a stronger upward lifting motion which leads to larger CO total column values, while the poor dispersion in central and southern Alberta exacerbates the surface CO pollution. Interannual variations in satellite data depict a slightly decreasing trend for both regions, while the decline trend is more evident from ground observations, especially at the urban sites. MOPITT CO vertical

  9. Spatial and temporal variation of CO over Alberta using measurements from satellite, aircrafts, and ground stations

    NASA Astrophysics Data System (ADS)

    Marey, H. S.; Hashisho, Z.; Fu, L.; Gille, J.

    2014-12-01

    Alberta is Canada's largest oil producer and its oil sand deposits comprise 30% of the world's oil reserves. The process of bitumen extraction and upgrading releases trace gases and aerosols to the atmosphere. In this study we present satellite-based analysis to explore, for the first time, various contributing factors that affect tropospheric carbon monoxide (CO) levels over Alberta. The multispectral product that uses both near-infrared (NIR) and the thermal-infrared (TIR) radiances for CO retrieval from the Measurements of Pollution in the Troposphere (MOPITT) are examined for the 12 year period from 2002-2013. Moderate Resolution Imaging Spectroradiometer (MODIS) thermal anomaly product from 2001 to 2013 is employed to investigate the seasonal and temporal variations of forest fires. Additionally, in situ CO measurements at industrial and urban sites are compared to satellite data. Furthermore, the available MOZAIC/IAGOS (Measurement of Ozone, Water Vapor, Carbon Monoxide, Nitrogen Oxide by Airbus In-Service Aircraft/In service Aircraft for Global Observing System) aircraft CO profiles (April 2009-December 2011) are used to validate MOPITT CO data. The climatological time curtain plot and spatial maps for CO over northern Alberta indicate the signatures of transported CO for two distinct biomass burning seasons, summer and spring. Distinct seasonal patterns of CO at the urban site s (Edmonton and Calgary cities) point to the strong influence of traffic. Meteorological parameters play an important role on the CO spatial distribution at various pressure levels. Northern Alberta shows stronger upward lifting motion which leads to larger CO total column values while the poor dispersion in central and south Alberta exacerbates the surface CO pollution. Inter-annual variations of satellite data depict a slightly decreasing trend for both regions while the decline trend is more evident from ground observations, especially at the urban sites. MOPITT CO vertical

  10. Validation of XCO2 derived from SWIR spectra of GOSAT TANSO-FTS with aircraft measurement data

    NASA Astrophysics Data System (ADS)

    Inoue, M.; Morino, I.; Uchino, O.; Miyamoto, Y.; Yoshida, Y.; Yokota, T.; Machida, T.; Sawa, Y.; Matsueda, H.; Sweeney, C.; Tans, P. P.; Andrews, A. E.; Biraud, S. C.; Tanaka, T.; Kawakami, S.; Patra, P. K.

    2013-10-01

    Column-averaged dry air mole fractions of carbon dioxide (XCO2) retrieved from Greenhouse gases Observing SATellite (GOSAT) Short-Wavelength InfraRed (SWIR) observations were validated with aircraft measurements by the Comprehensive Observation Network for TRace gases by AIrLiner (CONTRAIL) project, the National Oceanic and Atmospheric Administration (NOAA), the US Department of Energy (DOE), the National Institute for Environmental Studies (NIES), the HIAPER Pole-to-Pole Observations (HIPPO) program, and the GOSAT validation aircraft observation campaign over Japan. To calculate XCO2 based on aircraft measurements (aircraft-based XCO2), tower measurements and model outputs were used for additional information near the surface and above the tropopause, respectively. Before validation, we investigated the impacts of GOSAT SWIR column averaging kernels (CAKs) and the shape of a priori profiles on the aircraft-based XCO2 calculation. The differences between aircraft-based XCO2 with and without the application of GOSAT CAK were evaluated to be less than ±0.4 ppm at most, and less than ±0.1 ppm on average. Therefore, we concluded that the GOSAT CAK produces only a minor effect on the aircraft-based XCO2 calculation in terms of the overall uncertainty of GOSAT XCO2. We compared GOSAT data retrieved within ±2 or ±5° latitude/longitude boxes centered at each aircraft measurement site to aircraft-based data measured on a GOSAT overpass day. The results indicated that GOSAT XCO2 over land regions agreed with aircraft-based XCO2, except that the former is biased by -0.68 ppm (-0.99 ppm) with a standard deviation of 2.56 ppm (2.51 ppm), whereas the averages of the differences between the GOSAT XCO2 over ocean and the aircraft-based XCO2 were -1.82 ppm (-2.27 ppm) with a standard deviation of 1.04 ppm (1.79 ppm) for ±2° (±5°) boxes.

  11. Fault Detection of Aircraft System with Random Forest Algorithm and Similarity Measure

    PubMed Central

    Park, Wookje; Jung, Sikhang

    2014-01-01

    Research on fault detection algorithm was developed with the similarity measure and random forest algorithm. The organized algorithm was applied to unmanned aircraft vehicle (UAV) that was readied by us. Similarity measure was designed by the help of distance information, and its usefulness was also verified by proof. Fault decision was carried out by calculation of weighted similarity measure. Twelve available coefficients among healthy and faulty status data group were used to determine the decision. Similarity measure weighting was done and obtained through random forest algorithm (RFA); RF provides data priority. In order to get a fast response of decision, a limited number of coefficients was also considered. Relation of detection rate and amount of feature data were analyzed and illustrated. By repeated trial of similarity calculation, useful data amount was obtained. PMID:25057508

  12. Radiation profiles through the atmosphere measured by an auto controlled glider aircraft

    NASA Astrophysics Data System (ADS)

    Kräuchi, Andreas; Philipona, Rolf

    2014-05-01

    In 2011 radiation measurements through the atmosphere were made with a balloon borne short- and longwave net radiometer. These measurements were very promising and therefore new and improved sensors from Kipp&Zonen were used to equip a glider aircraft together with the standard Swiss radiosonde from Meteolabor AG. The glider serves as returning platform for the expensive and well calibrated radiation sensors. Double balloon technique is used to prevent pendulum motion during the ascent and to keep the radiation instruments as horizontal as possible. The built-in autopilot allows to return the gliderradiosonde to the launch site or to land it on predefined open space, which makes recovery much easier. The new return gliderradiosonde technique as well as new measurement possibilities will be shown. First measurements show radiation profiles through the atmosphere during different cloud conditions. Radiation profiles during different daytimes show the temporal resolution of vertical radiation profiles trough the atmosphere.

  13. Polarized Imaging Nephelometer for Field and Aircraft Measurements of Aerosol Phase Function

    NASA Astrophysics Data System (ADS)

    Dolgos, G.; Martins, J.

    2012-12-01

    Aerosols have a significant impact on the radiative balance and water cycle of our planet through influencing atmospheric radiation. Remote sensing of aerosols relies on scattering phase matrix information to retrieve aerosol properties with frequent global coverage. At the Laboratory for Aerosols, Clouds and Optics (LACO) at the University of Maryland, Baltimore County we developed a new technique to directly measure the aerosol phase function and the degree of linear polarization of the scattered light (two elements of the phase matrix). We designed and built a portable instrument called the Polarized Imaging Nephelometer (PI-Neph). The PI-Neph successfully participated in dozens of flights of the NASA Development and Evaluation of satellite ValidatiOn Tools by Experimenters (DEVOTE) project and the Deep Convective Clouds and Chemistry (DC3) project. The ambient aerosol enters the PI-Neph through an inlet and the sample is illuminated by laser light (wavelength of 532 nm); the scattered light is imaged by a stationary wide field of view camera in the scattering angle range of 2° to 178°. (In some cases stray light limited the scattering angle range to 3° to 176°). The PI-Neph measurement of phase function and the AERONET (AErosol RObotic NETwork) retrievals have already been compared in some cases when the aircraft spiraled over AERONET sites, for example at NASA's Wallops Flight Facility, on October 18 2011, as shown in Figure 1. The differences between the PI-Neph and the AERONET retrievals can be attributed to differences between the ambient size distribution and the one sampled inside the aircraft. The data that is resolved with respect to scattering angle is used to compute the volume scattering coefficient. The above mentioned October 18 flight data showed good agreement between the PI-Neph measurements of volume scattering coefficient and the parallel TSI integrating nephelometer measurements. On average the TSI measurements were 1.02 times the PI

  14. Velocity-Aided Attitude Estimation for Helicopter Aircraft Using Microelectromechanical System Inertial-Measurement Units

    PubMed Central

    Lee, Sang Cheol; Hong, Sung Kyung

    2016-01-01

    This paper presents an algorithm for velocity-aided attitude estimation for helicopter aircraft using a microelectromechanical system inertial-measurement unit. In general, high- performance gyroscopes are used for estimating the attitude of a helicopter, but this type of sensor is very expensive. When designing a cost-effective attitude system, attitude can be estimated by fusing a low cost accelerometer and a gyro, but the disadvantage of this method is its relatively low accuracy. The accelerometer output includes a component that occurs primarily as the aircraft turns, as well as the gravitational acceleration. When estimating attitude, the accelerometer measurement terms other than gravitational ones can be considered as disturbances. Therefore, errors increase in accordance with the flight dynamics. The proposed algorithm is designed for using velocity as an aid for high accuracy at low cost. It effectively eliminates the disturbances of accelerometer measurements using the airspeed. The algorithm was verified using helicopter experimental data. The algorithm performance was confirmed through a comparison with an attitude estimate obtained from an attitude heading reference system based on a high accuracy optic gyro, which was employed as core attitude equipment in the helicopter. PMID:27973429

  15. Velocity-Aided Attitude Estimation for Helicopter Aircraft Using Microelectromechanical System Inertial-Measurement Units.

    PubMed

    Lee, Sang Cheol; Hong, Sung Kyung

    2016-12-11

    This paper presents an algorithm for velocity-aided attitude estimation for helicopter aircraft using a microelectromechanical system inertial-measurement unit. In general, high- performance gyroscopes are used for estimating the attitude of a helicopter, but this type of sensor is very expensive. When designing a cost-effective attitude system, attitude can be estimated by fusing a low cost accelerometer and a gyro, but the disadvantage of this method is its relatively low accuracy. The accelerometer output includes a component that occurs primarily as the aircraft turns, as well as the gravitational acceleration. When estimating attitude, the accelerometer measurement terms other than gravitational ones can be considered as disturbances. Therefore, errors increase in accordance with the flight dynamics. The proposed algorithm is designed for using velocity as an aid for high accuracy at low cost. It effectively eliminates the disturbances of accelerometer measurements using the airspeed. The algorithm was verified using helicopter experimental data. The algorithm performance was confirmed through a comparison with an attitude estimate obtained from an attitude heading reference system based on a high accuracy optic gyro, which was employed as core attitude equipment in the helicopter.

  16. Model-based aviation advice on distal volcanic ash clouds by assimilating aircraft in situ measurements

    NASA Astrophysics Data System (ADS)

    Fu, Guangliang; Heemink, Arnold; Lu, Sha; Segers, Arjo; Weber, Konradin; Lin, Hai-Xiang

    2016-07-01

    The forecast accuracy of distal volcanic ash clouds is important for providing valid aviation advice during volcanic ash eruption. However, because the distal part of volcanic ash plume is far from the volcano, the influence of eruption information on this part becomes rather indirect and uncertain, resulting in inaccurate volcanic ash forecasts in these distal areas. In our approach, we use real-life aircraft in situ observations, measured in the northwestern part of Germany during the 2010 Eyjafjallajökull eruption, in an ensemble-based data assimilation system combined with a volcanic ash transport model to investigate the potential improvement on the forecast accuracy with regard to the distal volcanic ash plume. We show that the error of the analyzed volcanic ash state can be significantly reduced through assimilating real-life in situ measurements. After a continuous assimilation, it is shown that the aviation advice for Germany, the Netherlands and Luxembourg can be significantly improved. We suggest that with suitable aircrafts measuring once per day across the distal volcanic ash plume, the description and prediction of volcanic ash clouds in these areas can be greatly improved.

  17. Measurement and computer simulation of antennas on ships and aircraft for results of operational reliability

    NASA Astrophysics Data System (ADS)

    Kubina, Stanley J.

    1989-09-01

    The review of the status of computational electromagnetics by Miller and the exposition by Burke of the developments in one of the more important computer codes in the application of the electric field integral equation method, the Numerical Electromagnetic Code (NEC), coupled with Molinet's summary of progress in techniques based on the Geometrical Theory of Diffraction (GTD), provide a clear perspective on the maturity of the modern discipline of computational electromagnetics and its potential. Audone's exposition of the application to the computation of Radar Scattering Cross-section (RCS) is an indication of the breadth of practical applications and his exploitation of modern near-field measurement techniques reminds one of progress in the measurement discipline which is essential to the validation or calibration of computational modeling methodology when applied to complex structures such as aircraft and ships. The latter monograph also presents some comparison results with computational models. Some of the results presented for scale model and flight measurements show some serious disagreements in the lobe structure which would require some detailed examination. This also applies to the radiation patterns obtained by flight measurement compared with those obtained using wire-grid models and integral equation modeling methods. In the examples which follow, an attempt is made to match measurements results completely over the entire 2 to 30 MHz HF range for antennas on a large patrol aircraft. The problem of validating computer models of HF antennas on a helicopter and using computer models to generate radiation pattern information which cannot be obtained by measurements are discussed. The use of NEC computer models to analyze top-side ship configurations where measurement results are not available and only self-validation measures are available or at best comparisons with an alternate GTD computer modeling technique is also discussed.

  18. Eddy Covariance flux measurements with a weight-shift microlight aircraft

    NASA Astrophysics Data System (ADS)

    Metzger, S.; Junkermann, W.; Mauder, M.; Beyrich, F.; Butterbach-Bahl, K.; Schmid, H. P.; Foken, T.

    2012-03-01

    The objective of this study is to assess the feasibility and quality of Eddy-Covariance flux measurements from a weight-shift microlight aircraft (WSMA). Firstly we investigate the precision of the wind measurement (σu,v≤ 0.09 m s-1, σw = 0.04 m s-1), the lynchpin of flux calculations from aircraft. From here the smallest resolvable changes in friction velocity (0.02 m s-1,and sensible- (5 W m-2) and latent (3 W m-2) heat flux are estimated. Secondly a seven-day flight campaign was performed near Lindenberg (Germany). Here we compare measurements of wind, temperature, humidity and respective fluxes between a tall tower and the WSMA. The maximum likelihood functional relationship (MLFR) between tower and WSMA measurements considers the random error in the data, and shows very good agreement of the scalar averages. The MLFRs for standard deviations (SDs, 2-34%) and fluxes (17-21%) indicate higher estimates of the airborne measurements compared to the tower. Considering the 99.5% confidence intervals the observed differences are not significant, with exception of the temperature SD. The comparison with a large-aperture scintillometer reveals lower sensible heat flux estimates at both, tower (-40--25%) and WSMA (-25-0%). We relate the observed differences to (i) inconsistencies in the temperature and wind measurement at the tower and (ii) the measurement platforms differing abilities to capture contributions from non-propagating eddies. These findings encourage the use of WSMA as a low price and highly versatile flux measurement platform.

  19. Experimental Measurements of the Effects of Photo-chemical Oxidation on Aerosol Emissions in Aircraft Exhaust

    NASA Astrophysics Data System (ADS)

    Miracolo, M. A.; Presto, A. A.; Hennigan, C. J.; Nguyen, N.; Ranjan, M.; Reeder, A.; Lipsky, E.; Donahue, N. M.; Robinson, A. L.

    2009-12-01

    Many military and commercial airfields are located in non-attainment areas for particulate matter (PM2.5), but the contribution of emissions from in-use aircraft to local and regional PM2.5 concentrations is uncertain. In collaboration with the Pennsylvania Air National Guard 171st Air Refueling Wing, the Carnegie Mellon University (CMU) Mobile Laboratory was deployed to measure fresh and aged emissions from a CFM56-2B1 gas-turbine engine mounted on a KC-135 Stratotanker airframe. The CFM-56 family of engine powers many different types of military and civilian aircraft, including the Boeing 737 and several Airbus models. It is one of the most widely deployed models of engines in the world. The goal of this work was to measure the gas-particle partitioning of the fresh emissions at atmospherically relevant conditions and to investigate the effect of atmospheric oxidation on aerosol loadings as the emissions age. Emissions were sampled from an inlet installed one meter downstream of the engine exit plane and transferred into a portable smog chamber via a heated inlet line. Separate experiments were conducted at different engine loads ranging from ground idle to take-off rated thrust. During each experiment, some diluted exhaust was added to the chamber and the volatility of the fresh emissions was then characterized using a thermodenuder. After this characterization, the chamber was exposed to either ambient sunlight or UV lights to initiate photochemical oxidation, which produced secondary aerosol and ozone. A suite of gas and particle-phase instrumentation was used to characterize the evolution of the gas and particle-phase emissions, including an aerosol mass spectrometer (AMS) to measure particle size and composition distributions. Fresh emissions of fine particles varied with engine load with peak emission factors at low and high loads. At high engine loads, the fresh emissions were dominated by black carbon; at low loads volatile organic carbon emissions were

  20. SIERRA-Flux: Measuring Regional Surface Fluxes of Carbon Dioxide, Methane, and Water Vapor from an Unmanned Aircraft System

    NASA Technical Reports Server (NTRS)

    Fladeland; Yates, Emma Louise; Bui, Thaopaul Van; Dean-Day, Jonathan; Kolyer, Richard

    2011-01-01

    The Eddy-Covariance Method for quantifying surface-atmosphere fluxes is a foundational technique for measuring net ecosystem exchange and validating regional-to-global carbon cycle models. While towers or ships are the most frequent platform for measuring surface-atmosphere exchange, experiments using aircraft for flux measurements have yielded contributions to several large-scale studies including BOREAS, SMACEX, RECAB by providing local-to-regional coverage beyond towers. The low-altitude flight requirements make airborne flux measurements particularly dangerous and well suited for unmanned aircraft.

  1. DOAS measurements of NO2 from an ultralight aircraft during the Earth Challenge expedition

    NASA Astrophysics Data System (ADS)

    Merlaud, A.; van Roozendael, M.; van Gent, J.; Fayt, C.; Maes, J.; Toledo, X.; Ronveaux, O.; de Mazière, M.

    2012-02-01

    We report on airborne Differential Optical Absorption Spectroscopy (DOAS) measurements of NO2 tropospheric columns above South Asia, Arabic peninsula, North Africa, and Italy in November and December 2009. The DOAS instrument was installed on an ultralight aircraft involved in the Earth Challenge project, an expedition of seven pilots flying on four ultralight aircraft between Australia and Belgium. The instrument recorded spectra in limb geometry with a large field-of-view, a set-up which provides a high sensitivity to the boundary layer NO2 while minimizing the uncertainties related to the attitude variations. We compare our measurements with OMI and GOME-2 tropospheric NO2 products when the latter are available. Above Rajasthan and the Po Valley, two areas where the NO2 field is homogeneous, data sets agree very well. Our measurements in this areas are respectively 0.1 ± 0.1 to 2.8 ± 1 × 1015 molec cm-2 and 2.5 ± 0.5 × 1016 molec cm-2. Flying downwind of Riyadh, our NO2 measurements show with a higher spatial resolution than OMI the structure of the megacities'exhaust plume. Moreover, our measurements indicate larger columns (up to 70%) than the one seen by satellites. We also derived tropopsheric columns when no satellite data was available, if it was possible to get information on the visibility from satellite measurements of aerosol optical thickness. The maximum column we measured was above Benghazi, with 5.7 ± 2 × 1016 molec cm-2. This experiment also provides a confirmation for the recent finding of a soil signature above desert.

  2. Retrieval of ozone column content from airborne Sun photometer measurements during SOLVE II: comparison with coincident satellite and aircraft measurements

    NASA Astrophysics Data System (ADS)

    Livingston, J. M.; Schmid, B.; Russell, P. B.; Eilers, J. A.; Kolyer, R. W.; Redemann, J.; Ramirez, S. R.; Yee, J.-H.; Swartz, W. H.; Trepte, C. R.; Thomason, L. W.; Pitts, M. C.; Avery, M. A.; Randall, C. E.; Lumpe, J. D.; Bevilacqua, R. M.; Bittner, M.; Erbertseder, T.; McPeters, R. D.; Shetter, R. E.; Browell, E. V.; Kerr, J. B.; Lamb, K.

    2005-08-01

    During the 2003 SAGE (Stratospheric Aerosol and Gas Experiment) III Ozone Loss and Validation Experiment (SOLVE) II, the fourteen-channel NASA Ames Airborne Tracking Sunphotometer (AATS-14) was mounted on the NASA DC-8 aircraft and measured spectra of total and aerosol optical depth (TOD and AOD) during the sunlit portions of eight science flights. Values of ozone column content above the aircraft have been derived from the AATS-14 measurements by using a linear least squares method that exploits the differential ozone absorption in the seven AATS-14 channels located within the Chappuis band. We compare AATS-14 columnar ozone retrievals with temporally and spatially near-coincident measurements acquired by the SAGE III and the Polar Ozone and Aerosol Measurement (POAM) III satellite sensors during four solar occultation events observed by each satellite. RMS differences are 19 DU (7% of the AATS value) for AATS-SAGE and 10 DU (3% of the AATS value) for AATS-POAM. In these checks of consistency between AATS-14 and SAGE III or POAM III ozone results, the AATS-14 analyses use airmass factors derived from the relative vertical profiles of ozone and aerosol extinction obtained by SAGE III or POAM III.

    We also compare AATS-14 ozone retrievals for measurements obtained during three DC-8 flights that included extended horizontal transects with total column ozone data acquired by the Total Ozone Mapping Spectrometer (TOMS) and the Global Ozone Monitoring Experiment (GOME) satellite sensors. To enable these comparisons, the amount of ozone in the column below the aircraft is estimated either by assuming a climatological model or by combining SAGE and/or POAM data with high resolution in-situ ozone measurements acquired by the NASA Langley Research Center chemiluminescent ozone sensor, FASTOZ, during the aircraft vertical profile at the start or end of each flight. Resultant total column ozone values agree with corresponding TOMS and GOME

  3. A new fast response instrument for measuring total water content from aircraft

    NASA Astrophysics Data System (ADS)

    Nicholls, S.; Leighton, J.; Barker, R.

    1990-10-01

    A device for measuring the total water content of a parcel of air from an aircraft has been developed. The total water of a parcel of air is a conserved quantity, independent of phase changes, provided there is no transport of water through the parcel boundaries. Current airborne hygrometers normally attempt to measure the water content in individual phases and the presence of other phases invariably influences the quality of the data. However, any liquid water or ice entering this new probe is efficiently evaporated and the resultant water vapor measured using a Lyman-alpha hygrometer. In airborne trials the device was calibrated against a cooled-mirror dewpoint device. Runs were conducted in warm stratocumulus tops, through small cumulus, in mixed-phase precipitation and cirrus cloud. In all cases the device was found to produce high quality, fast response data.

  4. Tip-Clearance Measurement in the First Stage of the Compressor of an Aircraft Engine.

    PubMed

    García, Iker; Przysowa, Radosław; Amorebieta, Josu; Zubia, Joseba

    2016-11-11

    In this article, we report the design of a reflective intensity-modulated optical fiber sensor for blade tip-clearance measurement, and the experimental results for the first stage of a compressor of an aircraft engine operating in real conditions. The tests were performed in a ground test cell, where the engine completed four cycles from idling state to takeoff and back to idling state. During these tests, the rotational speed of the compressor ranged between 7000 and 15,600 rpm. The main component of the sensor is a tetrafurcated bundle of optical fibers, with which the resulting precision of the experimental measurements was 12 µm for a measurement range from 2 to 4 mm. To get this precision the effect of temperature on the optoelectronic components of the sensor was compensated by calibrating the sensor in a climate chamber. A custom-designed MATLAB program was employed to simulate the behavior of the sensor prior to its manufacture.

  5. Tip-Clearance Measurement in the First Stage of the Compressor of an Aircraft Engine

    PubMed Central

    García, Iker; Przysowa, Radosław; Amorebieta, Josu; Zubia, Joseba

    2016-01-01

    In this article, we report the design of a reflective intensity-modulated optical fiber sensor for blade tip-clearance measurement, and the experimental results for the first stage of a compressor of an aircraft engine operating in real conditions. The tests were performed in a ground test cell, where the engine completed four cycles from idling state to takeoff and back to idling state. During these tests, the rotational speed of the compressor ranged between 7000 and 15,600 rpm. The main component of the sensor is a tetrafurcated bundle of optical fibers, with which the resulting precision of the experimental measurements was 12 µm for a measurement range from 2 to 4 mm. To get this precision the effect of temperature on the optoelectronic components of the sensor was compensated by calibrating the sensor in a climate chamber. A custom-designed MATLAB program was employed to simulate the behavior of the sensor prior to its manufacture. PMID:27845709

  6. Feasibility of a nuclear gauge for fuel quantity measurement aboard aircraft

    NASA Technical Reports Server (NTRS)

    Signh, J. J.; Mall, G. H.; Sprinkle, D. R.; Chegini, H.

    1986-01-01

    Capacitance fuel gauges have served as the basis for fuel quantity indicating systems in aircraft for several decades. However, there have been persistent reports by the airlines that these gauges often give faulty indications due to microbial growth and other contaminants in the fuel tanks. This report describes the results of a feasibility study of using gamma ray attenuation as the basis for measuring fuel quantity in the tanks. Studies with a weak Am-241 59.5-keV radiation source indicate that it is possible to continuously monitor the fuel quantity in the tanks to an accuracy of better than 1 percent. These measurements also indicate that there are easily measurable differences in the physical properties and resultant attenuation characteristics of JP-4, JP-5, and Jet A fuels. The experimental results, along with a suggested source-detector geometrical configuration are described.

  7. Two-frequency /Delta k/ microwave scatterometer measurements of ocean wave spectra from an aircraft

    NASA Technical Reports Server (NTRS)

    Johnson, J. W.; Jones, W. L.; Weissman, D. E.

    1981-01-01

    A technique for remotely sensing the large-scale gravity wave spectrum on the ocean surface using a two frequency (Delta k) microwave scatterometer has been demonstrated from stationary platforms and proposed from moving platforms. This measurement takes advantage of Bragg type resonance matching between the electromagnetic wavelength at the difference frequency and the length of the large-scale surface waves. A prominent resonance appears in the cross product power spectral density (PSD) of the two backscattered signals. Ku-Band aircraft scatterometer measurements were conducted by NASA in the North Sea during the 1979 Maritime Remote Sensing (MARSEN) experiment. Typical examples of cross product PSD's computed from the MARSEN data are presented. They demonstrate strong resonances whose frequency and bandwidth agree with the surface characteristics and the theory. Directional modulation spectra of the surface reflectivity are compared to the gravity wave spectrum derived from surface truth measurements.

  8. Aircraft measurements of biomass burning aerosol over West Africa during DABEX

    NASA Astrophysics Data System (ADS)

    Johnson, B. T.; Osborne, S. R.; Haywood, J. M.; Harrison, M. A. J.

    2008-12-01

    This paper investigates the properties of biomass burning aerosols over West Africa using data from the UK FAAM aircraft during the Dust and Biomass-burning Experiment (DABEX). Aged biomass burning aerosols were widespread across the region, often at altitudes up to 4 km. Fresh biomass burning aerosols were observed at low altitudes by flying through smoke plumes from agricultural fires. The aircraft measured aerosol size distributions, optical properties, and vertical distributions. Single scattering albedo varied from 0.73 to 0.93 (at 0.55 μm) in aerosol layers dominated by biomass burning aerosol. We attribute much of this variation to the variable proportion of mineral dust and biomass burning aerosol. We estimate the single scattering albedo of aged biomass burning aerosol to be around 0.81 with an instrumental uncertainty of ±0.05. External mixing, and possibly internal mixing, between the biomass burning aerosol and mineral dust presents an additional source of uncertainty in this estimate. The size distributions of biomass burning aerosols were dominated by particles with radii smaller than 0.35 μm. A 20% increase of count mean radius was observed when contrasting fresh and aged biomass burning aerosols, accompanied by changes in the shape of the size distribution. These changes suggest growth by coagulation and condensation. Extinction coefficients, asymmetry parameters, and Angstrom exponents are calculated from Mie theory, using the lognormal fits to the measured size distributions and assumed refractive indices.

  9. DOAS measurements of NO2 from an ultralight aircraft during the Earth Challenge expedition

    NASA Astrophysics Data System (ADS)

    Merlaud, A.; Van Roozendael, M.; van Gent, J.; Fayt, C.; Maes, J.; Toledo-Fuentes, X.; Ronveaux, O.; De Mazière, M.

    2012-08-01

    We report on airborne Differential Optical Absorption Spectroscopy (DOAS) measurements of NO2 tropospheric columns above South Asia, the Arabic peninsula, North Africa, and Italy in November and December 2009. The DOAS instrument was installed on an ultralight aircraft involved in the Earth Challenge project, an expedition of seven pilots flying on four ultralight aircraft between Australia and Belgium. The instrument recorded spectra in limb geometry with a large field of view, a set-up which provides a high sensitivity to the boundary layer NO2 while minimizing the uncertainties related to the attitude variations. We compare our measurements with OMI (Ozone Monitoring Instrument) and GOME-2 (Global Ozone Monitoring Experiment 2) tropospheric NO2 products when the latter are available. Above Rajasthan and the Po Valley, two areas where the NO2 field is homogeneous, data sets agree very well. Our measurements in these areas are 0.1 ± 0.1 to 3 ± 1 × 1015 molec cm-2 and 2.6 ± 0.8 × 1016 molec cm-2, respectively. Flying downwind of Riyadh, our NO2 measurements show the structure of the megacity's exhaust plume with a higher spatial resolution than OMI. Moreover, our measurements are larger (up to 40%) than those seen by satellites. We also derived tropospheric columns when no satellite data were available if it was possible to get information on the visibility from satellite measurements of aerosol optical thickness. This experiment also provides a confirmation for the recent finding of a soil signature above desert.

  10. Airborne Sun photometer measurements of aerosol optical depth and columnar water vapor during the Puerto Rico Dust Experiment and comparison with land, aircraft, and satellite measurements

    NASA Astrophysics Data System (ADS)

    Livingston, John M.; Russell, Philip B.; Reid, Jeffrey S.; Redemann, Jens; Schmid, Beat; Allen, Duane A.; Torres, Omar; Levy, Robert C.; Remer, Lorraine A.; Holben, Brent N.; Smirnov, Alexander; Dubovik, Oleg; Welton, Ellsworth J.; Campbell, James R.; Wang, Jun; Christopher, Sundar A.

    2003-10-01

    Analyses of aerosol optical depth (AOD) and columnar water vapor (CWV) measurements obtained with the six-channel NASA Ames Airborne Tracking Sunphotometer (AATS-6) mounted on a twin-engine aircraft during the summer 2000 Puerto Rico Dust Experiment are presented. In general, aerosol extinction values calculated from AATS-6 AOD measurements acquired during aircraft profiles up to 5 km above sea level (asl) reproduce the vertical structure measured by coincident aircraft in situ measurements of total aerosol number concentration. AATS-6 extinction retrievals also agree with corresponding values derived from ground-based lidar measurements for altitudes above the trade inversion. The spectral behavior of AOD within specific layers beneath the top of the aircraft profile is consistent with attenuation of incoming solar radiation by large dust particles or by dust plus sea salt, with mean Ångström wavelength exponents of ˜0.20. Values of CWV calculated from profile measurements by AATS-6 at 941.9 nm and from aircraft in situ measurements agree to within ˜4% (0.13 g/cm2). AATS-6 AOD values measured on the ground at Roosevelt Roads Naval Air Station and during low-altitude aircraft runs over the adjacent Cabras Island aerosol/radiation ground site agree to within 0.004-0.030 with coincident data obtained with an AERONET Sun/sky radiometer located on Cabras Island. For the same observation times, AERONET retrievals of CWV exceed AATS-6 values by ˜21%. AATS-6 AOD values measured during low-altitude aircraft traverses over the ocean are compared with corresponding AOD values retrieved over water from upwelling radiance measurements by the Moderate-Resolution Imaging Spectroradiometer (MODIS), Total Ozone Mapping Spectrometer (TOMS), and GOES 8 Imager satellite sensors, with mixed results.

  11. PIV Measurements of Chevrons on F400-Series Tactical Aircraft Nozzle Model

    NASA Technical Reports Server (NTRS)

    Bridges, James; Wernet, Mark P.; Frate, Franco C.

    2011-01-01

    Reducing noise of tactical jet aircraft has taken on fresh urgency as core engine technologies allow higher specific-thrust engines and as society become more concerned for the health of its military workforce. Noise reduction on this application has lagged the commercial field as incentives for quieting military aircraft have not been as strong as in their civilian counterparts. And noise reduction strategies employed on civilian engines may not be directly applicable due to the differences in exhaust system architecture and mission. For instance, the noise reduction technology of chevrons, examined in this study, will need to be modified to take into account the special features of tactical aircraft nozzles. In practice, these nozzles have divergent slats that are tied to throttle position, and at take off the jet flow is highly overexpanded as the nozzle is optimized for cruise altitude rather than sea level. In simple oil flow visualization experiments conducted at the onset of the current test program flow barely stays attached at end of nozzle at takeoff conditions. This adds a new twist to the design of chevrons. Upon reaching the nozzle exit the flow shrinks inward radially, meaning that for a chevron to penetrate the flow it must extend much farther away from the baseline nozzle streamline. Another wrinkle is that with a variable divergence angle on the nozzle, the effective penetration will differ with throttle position and altitude. The final note of realism introduced in these experiments was to simulate the manner in which bypass flow is bled into the nozzle wall in real engines to cool the nozzle, which might cause very fat boundary layer at exit. These factors, along with several other issues specific to the application of chevrons to convergent-divergent nozzles have been explored with particle image velocimetry measurements and are presented in this paper.

  12. SRTM C and X Band Measurements of Water Elevations in Ohio and the Amazon

    NASA Astrophysics Data System (ADS)

    Kiel, B.; Alsdorf, D.; Lefavour, G.

    2005-12-01

    Hydrologists, water resource managers, and engineers recognize the potential of remote sensing for acquiring hydraulic measurements necessary for estimating discharge and storage changes globally, and thus have formed a community proposing the Water Elevation Recovery satellite mission (WatER). The WatER technological heritage is directly based on the highly successful Shuttle Radar Topography Mission (SRTM) and its C-band and X-band digital elevation models (DEMs). SRTM is not only a technological heritage for WatER but also a baseline measurement by which we can assess the potential of remote sensing to collect measurements of h, dh/dx and dh/dt. Water surface elevations are abundant in both the C-band and X-band SRTM DEMs. Elevations from three Ohio reservoirs and several Amazon floodplain lakes have standard deviations, interpreted as errors, that are smaller in C-band compared to X-band and are smaller in Ohio than in the Amazon. These trends are also evident when comparing water surface elevations from the Muskingum River in Ohio with those of the Amazon River. Differences are attributed to increased averaging in C-band compared to X-band, greater sensitivity to surface water motion in X-band, and generally larger off-nadir look angles in X-band. Absolute water surface elevations are greater in the C-band DEM for much of the two study areas and yield expected slope values on the Amazon River. However, X-band DEM values for the Amazon River are below sea level downstream of Sao Jose do Amatari (~600 km upstream of Obidos) and have some slope values that are greater than expected. These absolute height and slope differences are attributed to the usage of differing vertical datums.

  13. Long-term airborne black carbon measurements on a Lufthansa passenger aircraft

    NASA Astrophysics Data System (ADS)

    Ditas, Jeannine; Su, Hang; Scharffe, Dieter; Wang, Siwen; Zhang, Yuxuan; Brenninkmeijer, Carl; Pöschl, Ulrich; Cheng, Yafang

    2016-04-01

    Aerosol particles containing black carbon are the most absorbing component of incoming solar radiation and exert a significant positive radiative forcing thus forming next to CO² the strongest component of current global warming (Bond, 2013). Nevertheless, the role of black carbon particles and especially their complex interaction with clouds needs further research which is hampered by the limited experimental data, especially observations in the free and upper troposphere, and in the UTLS (upper troposphere and lower stratosphere). Many models underestimate the global atmospheric absorption attributable to black carbon by a factor of almost 3 (Bond, 2013). In August 2014, a single particle soot photometer was included in the extensive scientific payload of the CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) project. CARIBIC is in operation since 1997 (with an interruption for 2002-2005) and carries out systematic observations at 10-12 km altitude. For this a special air freight container combining different instruments is transported on a monthly basis using a Lufthansa Airbus A340-600 passenger aircraft with destinations from 120°W to 120°E and 10°N to 75°N. The container has equipment for trace gas analyses and sampling and aerosol analyses and sampling and is connected to an inlet system that is part of the aircraft which contains a camera and DOAS remote sensing system. The integration of a single particle soot photometer (SP2) offers the possibility for the first long-term measurement of global distribution of black carbon and so far flights up to November 2015 have been conducted with more than 400 flight hours. So far the SP2 measurements have been analysed for flights over four continents from Munich to San Francisco, Sao Paulo, Tokyo, Beijing, Cape Town, Los Angeles and Hong Kong). The first measurements show promising results of black carbon measurements. Background concentrations in the UTLS

  14. Apparatus for direct measurement of ash fusion and sintering behavior at elevated temperatures and pressures

    NASA Astrophysics Data System (ADS)

    Khan, M. Rashid

    1989-10-01

    Ash fusion, sintering, and deposition may impose serious operational difficulties in conventional and advanced coal-combustion systems. Conventional ash fusion techniques (e.g., ASTM methods) determine the qualitative behavior of ash samples at atmospheric pressure. Presently, there is no known available technique that can measure the behavior of coal ash at elevated temperatures and pressures. In the literature, methods based on electrical resistance or shrinkage of coal ash have been reported at atmospheric pressure (elevated temperatures) conditions. A high-pressure microdilatometer (HPMD) has been developed to investigate ash fusion and sintering behavior at elevated pressures and temperatures by the simultaneous measurement of the temperature of initial contraction and electrical resistivity of samples. This novel technique facilitates the measurement of ash properties over a wide range of temperature, pressure, and gas atmosphere (oxidizing, reducing, or inert). The operating principle of the HPMD includes measuring the temperature at which there is a significant ``shift'' in the electrical resistivity (and/or sample volume) that represents ash sintering and fusion. Sintering occurs through the formation of solid-state, particle-to-particle ``necks'' or the appearance of a molten phase, which allows a path for electrical conductance. The ability to perform both resistivity and shrinkage measurements simultaneously or independently at elevated pressures makes the HPMD truly unique. The HPMD can also be used to investigate the swelling and softening behavior of pyrolyzing coal at elevated pressures and relatively rapid heating rates. The HPMD can provide insights into the sintering/fusion of coal ash or coal swelling at a range of conditions: (a) the influences of various gas atmospheres can be investigated, (b) the effects of pressure can be studied, (c) different temperature/heating rate schemes can be used (constant rates, isothermal holds below or above the

  15. Phased Acoustic Array Measurements of a 5.75 Percent Hybrid Wing Body Aircraft

    NASA Technical Reports Server (NTRS)

    Burnside, Nathan J.; Horne, William C.; Elmer, Kevin R.; Cheng, Rui; Brusniak, Leon

    2016-01-01

    Detailed acoustic measurements of the noise from the leading-edge Krueger flap of a 5.75 percent Hybrid Wing Body (HWB) aircraft model were recently acquired with a traversing phased microphone array in the AEDC NFAC (Arnold Engineering Development Complex, National Full Scale Aerodynamics Complex) 40- by 80-Foot Wind Tunnel at NASA Ames Research Center. The spatial resolution of the array was sufficient to distinguish between individual support brackets over the full-scale frequency range of 100 to 2875 Hertz. For conditions representative of landing and take-off configuration, the noise from the brackets dominated other sources near the leading edge. Inclusion of flight-like brackets for select conditions highlights the importance of including the correct number of leading-edge high-lift device brackets with sufficient scale and fidelity. These measurements will support the development of new predictive models.

  16. Comparison of wind tunnel and flyover noise measurements of the YOV-10A STOL aircraft

    NASA Technical Reports Server (NTRS)

    Atencio, A., Jr.; Soderman, P. T.

    1972-01-01

    The YOV-10A Research Aircraft was flown to obtain flyover noise data that could be compared to noise data measured in the 40- by 80- foot wind tunnel at NASA Ames Research Center. The flyover noise measurements were made during the early morning hours on runway 32L at Moffett Field, California. A number of passes were made at 50 ft altitude in level flight with an airplane configuration closely matching that tested in the wind tunnel. Two passes were selected as prime and were designated for full data reduction. The YOV-10A was flown over a microphone field geometrically similar to the microphone array set up in the wind tunnel. An acoustic center was chosen as a matching point for the data. Data from the wind tunnel and flyover were reduced and appropiate corrections were applied to compare the data. Results show that wind tunnel and flight test acoustic data agreed closely.

  17. Large-Eddy Simulations and Lidar Measurements of Vortex-Pair Breakup in Aircraft Wakes

    NASA Technical Reports Server (NTRS)

    Lewellen, D. C.; Lewellen, W. S.; Poole, L. R.; DeCoursey, R. J.; Hansen, G. M.; Hostetler, C. A.; Kent, G. S.

    1998-01-01

    Results of large-eddy simulations of an aircraft wake are compared with results from ground-based lidar measurements made at NASA Langley Research Center during the Subsonic Assessment Near-Field Interaction Flight Experiment field tests. Brief reviews of the design of the field test for obtaining the evolution of wake dispersion behind a Boeing 737 and of the model developed for simulating such wakes are given. Both the measurements and the simulations concentrate on the period from a few seconds to a few minutes after the wake is generated, during which the essentially two-dimensional vortex pair is broken up into a variety of three-dimensional eddies. The model and experiment show similar distinctive breakup eddies induced by the mutual interactions of the vortices, after perturbation by the atmospheric motions.

  18. High Time Resolution Measurements of Gaseous Oxidized Mercury from Ground and Aircraft Platforms

    NASA Astrophysics Data System (ADS)

    Lyman, S. N.; Jaffe, D. A.

    2009-12-01

    Atmospheric mercury fractions (gaseous elemental, gaseous oxidized, and fine particulate-bound mercury) have been measured in many different environmental conditions, primarily with the Tekran 2537/1130/1135 speciation system, and these measurements have greatly enhanced scientific understanding of atmospheric mercury dynamics. However, measurements of gaseous oxidized mercury, the most reactive, soluble, and bioavailable mercury fraction, have low time resolution with the Tekran system and have been mostly unchecked by calibration standards. We have developed an alternative technique for measuring gaseous oxidized mercury that provides higher resolution (2.5 minute) measurements, and have built a permeation tube-based oxidized mercury (HgCl2, HgBr2, and HgO) calibrator. The system measures oxidized mercury based on the difference between elemental mercury and total mercury measured with two Tekran 2537 analyzers, and has a 2.5 minute detection limit sufficient to quantify high oxidized mercury events (~80 pg m-3). Additionally, in laboratory tests it outperforms measurements made with KCl-coated denuders in terms of percent recovery and time-averaged detection limit. We have used this system in aircraft and at Mount Bachelor Observatory to observe the origins and dynamics of high oxidized mercury air in the Pacific Northwest, and are preparing it for deployment in the NCAR C-130 for detailed assessment of atmospheric mercury fractions in North America.

  19. Assimilating Aircraft-based measurements to improve the State of Distal Volcanic Ash Cloud

    NASA Astrophysics Data System (ADS)

    Fu, Guangliang; Lin, Hai Xiang; Heemink, Arnold; Segers, Arjo; Lu, Sha; Palsson, Thorgeir

    2015-04-01

    The sudden eruption at the 1666 m high, ice-capped Eyjafjallajökull volcano, in south Iceland during 14 April to 23 May 2010, had caused an unprecedented closure of the European and North Atlantic airspace resulting in global economic losses of US5 billion. This has initiated a lot of research on how to improve aviation advice after eruption onset. Good estimation of both the state of volcanic ash cloud and the emission of volcano are crucial for providing a successful aviation advice. Currently most of the approaches, employing satellite-based and ground-based measurements, are in the focus of improving the definition of Eruption Source Parameters (ESPs) such as plume height and mass eruption rate, which are certainly very important for estimating volcano emission and state of volcanic ash cloud near to the volcano. However, for ash cloud state in a far field, these approaches can hardly make improvements. This is mainly because the influence of ESPs on the ash plume becomes weaker as the distance to the volcano is getting farther, thus for a distal plume the information of ESPs will have little influence. This study aims to find an efficient way to improve the state of distal volcanic ash cloud. We use real-life aircraft-based observations, measured along Dutch border between Borken and Twist during the 2010 Eyjafjallajökull eruption, in an data assimilation system combining with a transport model to identify the potential benefit of this kind of observations and the influence on the ash state around Dutch border. We show that assimilating aircraft-based measurements can significantly improve the state of distal ash clouds, and further provide an improved aviation advice on distal ash plume. We compare the performances of different sequential data assimilation methods. The results show standard Ensemble Kalman Filter (EnKF) works better than others, which is because of the strong nonlinearity of the dynamics and the EnKF's resampling Gaussianity nature

  20. Measurement and prediction of noise from low-altitude military aircraft operations

    NASA Astrophysics Data System (ADS)

    Barry, Bernard F.; Payne, Richard C.; Harris, Anthony L.; Weston, Ralph J.

    1992-04-01

    In response to the rapid growth in demand for information on noise levels around military airfields in the UK, NPL developed AIRNOISE, a mathematical model for computing aircraft noise contours. Since its first applications in 1981, the model has been used to determine zones of eligibility within the MoD compensation scheme. The model has been subject to continuous development, e.g., the incorporation of Harrier V/STOL operations. We have now extended the model to include noise from high-speed, low-level operations. The model predicts not only maximum levels but the complete time-history, so that the time-onset rate can be estimated. To aid refinement and validation of the model, a special exercise has been conducted in which Tornado, Harrier, Jaguar, Hawk, F-15 and F-16 aircraft have flown straight and level at heights between about 100 and 400 feet, at various speeds and engine power settings over an array of microphones. This paper describes the trial and the results obtained. The prediction model is outlined and comparisons made between predictions and measurements.

  1. Aerodynamic Measurements of a Gulfstream Aircraft Model With and Without Noise Reduction Concepts

    NASA Technical Reports Server (NTRS)

    Neuhart, Dan H.; Hannon, Judith A.; Khorrami, Mehdi R.

    2014-01-01

    Steady and unsteady aerodynamic measurements of a high-fidelity, semi-span 18% scale Gulfstream aircraft model are presented. The aerodynamic data were collected concurrently with acoustic measurements as part of a larger aeroacoustic study targeting airframe noise associated with main landing gear/flap components, gear-flap interaction noise, and the viability of related noise mitigation technologies. The aeroacoustic tests were conducted in the NASA Langley Research Center 14- by 22-Foot Subsonic Wind Tunnel with the facility in the acoustically treated open-wall (jet) mode. Most of the measurements were obtained with the model in landing configuration with the flap deflected at 39º and the main landing gear on and off. Data were acquired at Mach numbers of 0.16, 0.20, and 0.24. Global forces (lift and drag) and extensive steady and unsteady surface pressure measurements were obtained. Comparison of the present results with those acquired during a previous test shows a significant reduction in the lift experienced by the model. The underlying cause was traced to the likely presence of a much thicker boundary layer on the tunnel floor, which was acoustically treated for the present test. The steady and unsteady pressure fields on the flap, particularly in the regions of predominant noise sources such as the inboard and outboard tips, remained unaffected. It is shown that the changes in lift and drag coefficients for model configurations fitted with gear/flap noise abatement technologies fall within the repeatability of the baseline configuration. Therefore, the noise abatement technologies evaluated in this experiment have no detrimental impact on the aerodynamic performance of the aircraft model.

  2. Within-footprint roughness measurements using ICESat/GLAS waveform and LVIS elevation

    NASA Astrophysics Data System (ADS)

    Li, Xiaolu; Xu, Kai; Xu, Lijun

    2016-12-01

    The surface roughness is an important characteristic over an ice sheet or glacier, since it is an identification of boundary-layer meteorology and is an important limiter on the accuracy of surface-height measurements. In this paper, we propose a simulation method to derive the within-footprint roughness (called simulation-derived roughness) using ICESat/GLAS echo waveform, laser vegetation imaging sensor (LVIS) elevations, and laser profile array (LPA) images of ICESat/GLAS. By dividing the within-footprint surface into several elements, a simulation echo waveform can be obtained as the sum of the elementary pulses reflected from each surface element. The elevation of the surface elements, which is utilized to get the return time of the elementary pulses, is implemented based on an LVIS interpolated elevation using a radial basis function (RBF) neural network. The intensity of the elementary pulses can be obtained from the thresholded LPA images. Based on the return time and the intensity of the elementary pulses, we used the particle swarm optimization (PSO) method to approximate the simulation waveform to the ICESat/GLAS echo waveform. The full width at half maximum) (FWHM) of the elementary pulse was extracted from the simulation waveform for estimating the simulation-derived roughness. By comparing with the elevation-derived roughness (derived from the elevation) and the waveform-derived roughness (derived from the ICESat/GLAS waveform), the proposed algorithm can exclude the slope effect from waveform width broadening for describing the roughness of the surface elements.

  3. The influence of the gait-related arm swing on elevation gain measured by sport watches

    PubMed Central

    Taube, Wolfgang; Neuhaus, Matthias; Wyss, Thomas

    2016-01-01

    Abstract The elevation gain is an important contributor to the total workload in endurance sports. The purpose of this study was to evaluate the influence of the arm swing on elevation gain in three sport watches (Garmin® Forerunner 910XT, Polar® RS800CX and Suunto® Ambit2) on a flat 400 m outdoor track. Altogether, a total of 120 repetitions of 1,200 m were performed at self-selected speeds corresponding to strolling, walking, jogging and running. During the assessment two devices of each sport watch, one secured on the hip and one on the wrist, were worn by the participants. A small but significant (effect size = .39; p < .001) influence of the arm swing on elevation was revealed in all sport watches. Elevation indication errors recorded on the wrist were significantly larger than the ones recorded on the hip (4.0-7.4 vs. 1.2-5.7 m per 1,200 m; p < .05). Furthermore, when wearing the devices on the wrist, errors in elevation indication increased when gait speed increased. Users should be aware that wearing the devices on the hip can significantly decrease measurement errors. This might be especially relevant for activities with high dynamics, such as jogging and running. PMID:28149368

  4. A comparison of vertical velocity in cirrus obtained from aircraft and lidar divergence measurements during FIRE. [First ISCCP Regional Experiment

    NASA Technical Reports Server (NTRS)

    Gultepe, Ismail; Heymsfield, A. J.; Lenschow, D. H.

    1990-01-01

    Techniques are presented to obtain vertical velocity in cirrus clouds from in situ aircraft lateral wind measurements and from ground-based remote Doppler lidar measurements. The approach used is to calculate w from the integral of the divergence of the horizontal velocity around a closed path. Divergence measurements from both aircraft and Doppler lidar are discussed. The principal errors in the calculation of w from aircraft lateral wind measurements are bias in the lateral wind, ground speed errors, and error due to vertical shear of the horizontal wind. For Doppler lidar measurements the principal errors are in the estimate of mean terminal velocity and the zeroth order coefficients of the Fourier series that is fitted to the data. The technique is applied to a cirrus cloud investigated during the FIRE (First International Satellite Cloud Climatology Regional Experiment) Cirrus Intensive Field Observation Program. The results indicate that the error in w is about + or - 14 cm/s from the aircraft technique; this can be reduced to about + or - 2 to 3 cm/s with technical improvements in both ground speed and lateral velocity measurements. The error in w from Doppler lidar measurements, which is about + or - 8 cm/s, can be reduced to about + or - 5 cm/s by improvements in the Doppler velocity measurements with technology that is currently available.

  5. A backward modeling study of intercontinental pollution transport using aircraft measurements

    NASA Astrophysics Data System (ADS)

    Stohl, A.; Forster, C.; Eckhardt, S.; Spichtinger, N.; Huntrieser, H.; Heland, J.; Schlager, H.; Wilhelm, S.; Arnold, F.; Cooper, O.

    2003-06-01

    In this paper we present simulations with a Lagrangian particle dispersion model to study the intercontinental transport of pollution from North America during an aircraft measurement campaign over Europe. The model was used for both the flight planning and a detailed source analysis after the campaign, which is described here with examples from two episodes. Forward calculations of emission tracers from North America, Europe, and Asia were made in order to understand the transport processes. Both episodes were preceded by stagnant conditions over North America, leading to the accumulation of pollutants in the North American boundary layer. Both anthropogenic sources and, to a lesser extent, forest fire emissions contributed to this pollution, which was then exported by warm conveyor belts to the middle and upper troposphere, where it was transported rapidly to Europe. Concentrations of many trace gases (CO, NOy, CO2, acetone, and several volatile organic compounds; O3 in one case) and of ambient atmospheric ions measured aboard the research aircraft were clearly enhanced in the pollution plumes compared to the conditions outside the plumes. Backward simulations with the particle model were introduced as an indispensable tool for a more detailed analysis of the plume's source region. They make trajectory analyses (which, to date, were mainly used to interpret aircraft measurement data) obsolete. Using an emission inventory, we could decompose the tracer mixing ratios at the receptors (i.e., along the flight tracks) into contributions from every grid cell of the inventory. For both plumes we found that emission sources contributing to the tracer concentrations over Europe were distributed over large areas in North America. In one case, sources in California, Texas, and Florida contributed almost equally, and smaller contributions were also made by other sources located between the Yucatan Peninsula and Canada. In the other case, sources in eastern North America

  6. Long-term Airborne Black Carbon Measurements on a Lufthansa Passenger Aircraft

    NASA Astrophysics Data System (ADS)

    Cheng, Y.; Su, H.; Ditas, J.; Scharffe, D.; Wang, S.; Zhang, Y.; McMeeking, G. R.; Brenninkmeijer, C. A. M.; Poeschl, U.

    2015-12-01

    Aerosol particles containing black carbon are the most absorbing component of incoming solar radiation and exert a significant positive radiative forcing thus forming next to CO2 the strongest component of current global warming. Nevertheless, the role of black carbon particles and especially their complex interaction with clouds needs further research which is hampered by the limited experimental data, especially observations in the free troposphere, and in the UTLS (upper troposphere and lower stratosphere). In August 2014, a single particle soot photometer (SP2) was included in the extensive scientific payload of the CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container) project. CARIBIC is in operation since 1997 and carries out systematic observations of trace gas and aerosol sampling and on-line analyses, as well as DOAS remote sensing system at 10-12 km altitude. For this a special air freight container combining different instruments is transported on a monthly basis using a Lufthansa Airbus A340-600 passenger aircraft with destinations from 120°W to 120°E and 10°N to 75°N. The integration of a SP2 offers the possibility for the first long-term measurement of global distribution of black carbon. Up to date the SP2 measurements have been analyzed for 392 flights hours over four continents (Fig. 1). The first measurements show promising results of black carbon including periods when background concentrations in the UTLS were encountered. Beside a general distribution of number and mass of black carbon particles, peak events were detected with up to 20 times higher concentrations compared to the background. Moreover, high concentration plumes have been observed continuously over a range of 10,000 km. Interestingly, our results show also a generally lower amount of black carbon mass in the tropics compared to the mid latitude northern hemisphere.

  7. Far-infrared sensor for cirrus (FIRSC): an aircraft-based Fourier-transform spectrometer to measure cloud radiance.

    PubMed

    Vanek, M D; Nolt, I G; Tappan, N D; Ade, P A; Gannaway, F C; Hamilton, P A; Lee, C; Davis, J E; Predko, S

    2001-05-01

    We describe an aircraft-based Fourier-transform spectrometer (FTS) designed to measure the Earth outgoing radiance spectrum in the far-infrared-submillimeter spectral range. The instrument features include a rapid-scan FTS to obtain high spatial resolution from a moving aircraft platform, a sensitive two-channel detector, and a CCD camera for recording the nadir cloud scene with each scan record. Such measurements demonstrate the sensitivity of Earth radiance to high clouds and provide spectral data for improving techniques for remote sensing and retrieval of atmospheric and cloud properties.

  8. Calibration of 3-D wind measurements on a single engine research aircraft

    NASA Astrophysics Data System (ADS)

    Mallaun, C.; Giez, A.; Baumann, R.

    2015-02-01

    An innovative calibration method for the wind speed measurement using a boom mounted Rosemount model 858 AJ air velocity probe is introduced. The method is demonstrated for a sensor system installed on a medium size research aircraft which is used for measurements in the atmospheric boundary layer. The method encounters a series of coordinated flight manoeuvres to directly estimate the aerodynamic influences on the probe and to calculate the measurement uncertainties. The introduction of a differential Global Positioning System (DGPS) combined with a high accuracy Inertial Reference System (IRS) has brought major advances to airborne measurement techniques. The exact determination of geometrical height allows the use of the pressure signal as an independent parameter. Furthermore, the exact height information and the stepwise calibration process lead to maximum accuracy. The results show a measurement uncertainty for the aerodynamic influence of the dynamic and static pressures of 0.1 hPa. The applied parametrisation does not require any height dependencies or time shifts. After extensive flight tests a correction for the flow angles (attack and sideslip angles) was found, which is necessary for a successful wind calculation. A new method is demonstrated to correct for the aerodynamic influence on the sideslip angle. For the 3-D wind vector (with 100 Hz resolution) a novel error propagation scheme is tested, which determines the measurement uncertainties to be 0.3 m s-1 for the horizontal and 0.2 m s-1 for the vertical wind components.

  9. Calibration of 3-D wind measurements on a single-engine research aircraft

    NASA Astrophysics Data System (ADS)

    Mallaun, C.; Giez, A.; Baumann, R.

    2015-08-01

    An innovative calibration method for the wind speed measurement using a boom-mounted Rosemount model 858 AJ air velocity probe is introduced. The method is demonstrated for a sensor system installed on a medium-size research aircraft which is used for measurements in the atmospheric boundary layer. The method encounters a series of coordinated flight manoeuvres to directly estimate the aerodynamic influences on the probe and to calculate the measurement uncertainties. The introduction of a differential Global Positioning System (DGPS) combined with a high-accuracy inertial reference system (IRS) has brought major advances to airborne measurement techniques. The exact determination of geometrical height allows the use of the pressure signal as an independent parameter. Furthermore, the exact height information and the stepwise calibration process lead to maximum accuracy. The results show a measurement uncertainty for the aerodynamic influence of the dynamic and static pressures of 0.1 hPa. The applied parametrisation does not require any height dependencies or time shifts. After extensive flight tests a correction for the flow angles (attack and sideslip angles) was found, which is necessary for a successful wind calculation. A new method is demonstrated to correct for the aerodynamic influence on the sideslip angle. For the three-dimensional (3-D) wind vector (with 100 Hz resolution) a novel error propagation scheme is tested, which determines the measurement uncertainties to be 0.3 m s-1 for the horizontal and 0.2 m s-1 for the vertical wind components.

  10. A Comparison of Measurements from ATMOS and Instruments Aboard the ER-2 Aircraft: Halogenated Gases

    NASA Technical Reports Server (NTRS)

    Chang, A. Y.; Salawitch, R. J.; Michelsen, H. A.; Gunson, M. R.; Abrams, M. C.; Zander, R.; Rinsland, C. P.; Elkins, J. W.; Dutton, G. S.; Volk, C. M.; Webster, C. R.; May, R. D.; Fahey, D. W.; Gao, R.-S.; Loewenstein, M.

    1996-01-01

    We compare volume mixing ratio profiles of N2O, CFC-11, CFC-12, CCl4, SF6, and HCl in the mid-latitude lower stratosphere measured by the ATMOS Fourier transform spectrometer on the ATLAS-3 Space Shuttle Mission with in situ measurements acquired from the NASA ER-2 aircraft during Nov. 1994. Good agreement is found between ATMOS and in situ correlations of [CFC-11], [CFC-12], and [SF6] with [N2O]. ATMOS measurements of [CCl4] are 15% high compared to ER-2 data, but agree within the systematic uncertainties. ATMOS observations of [HCl] vs [N2O] are within approximately 10% of ER-2 data for [HCl] > 1 ppbv, but exceed in situ measurements by larger fractional amounts for smaller [HCl]. ATMOS measurements of [ClONO2] agree well with values inferred from in situ observations of [ClO], [NO], and [O3]. The sum of [HCl] and [ClONO2] observed by ATMOS, supplemented by a minor contribution from [ClO] estimated with a photochemical model, is consistent with the levels of inorganic chlorine inferred from in situ measurements of chlorine source gases.

  11. Analysis of vibration induced error in turbulence velocity measurements from an aircraft wing tip boom

    NASA Technical Reports Server (NTRS)

    Akkari, S. H.; Frost, W.

    1982-01-01

    The effect of rolling motion of a wing on the magnitude of error induced due to the wing vibration when measuring atmospheric turbulence with a wind probe mounted on the wing tip was investigated. The wing considered had characteristics similar to that of a B-57 Cambera aircraft, and Von Karman's cross spectrum function was used to estimate the cross-correlation of atmospheric turbulence. Although the error calculated was found to be less than that calculated when only elastic bendings and vertical motions of the wing are considered, it is still relatively large in the frequency's range close to the natural frequencies of the wing. Therefore, it is concluded that accelerometers mounted on the wing tip are needed to correct for this error, or the atmospheric velocity data must be appropriately filtered.

  12. Cruise noise of an advanced single-rotation propeller measured from an adjacent aircraft

    NASA Technical Reports Server (NTRS)

    Woodward, Richard P.; Loeffler, Irvin J.; Ranaudo, Richard J.

    1989-01-01

    Results are reported from flight measurements of the noise from a full-scale SR-7L advanced single-rotation turbofan model mounted on the wing of the NASA Lewis Propfan Test Assessment (PTA) aircraft (a modified Gulfstream II). Data obtained on the PTA with an outboard microphone boom and by the NASA Lewis acoustically instrumented Learjet flying along several sidelines relative to the PTA are presented in tables and graphs and briefly discussed. It is found that the PTA-boom and Learjet sound levels are in good agreement at Mach 0.69 and altitude 20,000 ft, but the Learjet values are significantly lower than the boom levels at Mach 0.79 and altitude 36,000 ft.

  13. NO and NOy in the upper troposphere: Nine years of CARIBIC measurements onboard a passenger aircraft

    NASA Astrophysics Data System (ADS)

    Stratmann, G.; Ziereis, H.; Stock, P.; Brenninkmeijer, C. A. M.; Zahn, A.; Rauthe-Schöch, A.; Velthoven, P. V.; Schlager, H.; Volz-Thomas, A.

    2016-05-01

    Nitrogen oxide (NO and NOy) measurements were performed onboard an in-service aircraft within the framework of CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container). A total of 330 flights were completed from May 2005 through April 2013 between Frankfurt/Germany and destination airports in Canada, the USA, Brazil, Venezuela, Chile, Argentina, Colombia, South Africa, China, South Korea, Japan, India, Thailand, and the Philippines. Different regions show differing NO and NOy mixing ratios. In the mid-latitudes, observed NOy and NO generally shows clear seasonal cycles in the upper troposphere with a maximum in summer and a minimum in winter. Mean NOy mixing ratios vary between 1.36 nmol/mol in summer and 0.27 nmol/mol in winter. Mean NO mixing ratios range between 0.05 nmol/mol and 0.22 nmol/mol. Regions south of 40°N show no consistent seasonal dependence. Based on CO observations, low, median and high CO air masses were defined. According to this classification, more data was obtained in high CO air masses in the regions south of 40°N compared to the midlatitudes. This indicates that boundary layer emissions are more important in these regions. In general, NOy mixing ratios are highest when measured in high CO air masses. This dataset is one of the most comprehensive NO and NOy dataset available today for the upper troposphere and is therefore highly suitable for the validation of atmosphere-chemistry-models.

  14. Vertical distribution of aerosol optical properties based on aircraft measurements over the Loess Plateau in China.

    PubMed

    Li, Junxia; Liu, Xingang; Yuan, Liang; Yin, Yan; Li, Zhanqing; Li, Peiren; Ren, Gang; Jin, Lijun; Li, Runjun; Dong, Zipeng; Li, Yiyu; Yang, Junmei

    2015-08-01

    Vertical distributions of aerosol optical properties based on aircraft measurements over the Loess Plateau were measured for the first time during a summertime aircraft campaign, 2013 in Shanxi, China. Data from four flights were analyzed. The vertical distributions of aerosol optical properties including aerosol scattering coefficients (σsc), absorption coefficients (σab), Angström exponent (α), single scattering albedo (ω), backscattering ratio (βsc), aerosol mass scattering proficiency (Qsc) and aerosol surface scattering proficiency (Qsc(')) were obtained. The mean statistical values of σsc were 77.45 Mm(-1) (at 450 nm), 50.72 Mm(-1) (at 550n m), and 32.02 Mm(-1) (at 700 nm). The mean value of σab was 7.62 Mm(-1) (at 550 nm). The mean values of α, βsc and ω were 1.93, 0.15, and 0.91, respectively. Aerosol concentration decreased with altitude. Most effective diameters (ED) of aerosols were less than 0.8 μm. The vertical profiles of σsc,, α, βsc, Qsc and Qsc(') showed that the aerosol scattering properties at lower levels contributed the most to the total aerosol radiative forcing. Both α and βsc had relatively large values, suggesting that most aerosols in the observational region were small particles. The mean values of σsc, α, βsc, Qsc, Qsc('), σab and ω at different height ranges showed that most of the parameters decreased with altitude. The forty-eight hour backward trajectories of air masses during the observation days indicated that the majority of aerosols in the lower level contributed the most to the total aerosol loading, and most of these particles originated from local or regional pollution emissions.

  15. Low elevation angle KU-band satellite measurements at Austin, Texas

    NASA Technical Reports Server (NTRS)

    Vogel, Wolfhard J.; Torrence, Geoffrey W.; Ranganathan, Murali

    1989-01-01

    At low elevation angles, the propagation of satellite signals is affected by precipitation as well as by inhomogeneties of the refractive index. Whereas precipitation causes fades for relatively small percentages of time, the refractive index variability causes scintillations which can be observed for most of the time. An experiment is now under way in Austin, Texas, in which the right hand circularly polarized 12 GHz beacon of INTELSAT-V/F10 is observed at a 5.8 deg elevation angle, along with the radiometric sky temperature, rainfall rate, humidity, pressure, temperature, and wind speed and direction. The objective of these measurements is to accumulate a database over a period of 2 years and to analyze the probabilities and dynamical behavior of the signal variations in relation to the meteorological parameters. The hardware and software used for the data acquisition and analysis is described and the results from the first year of measurements are presented.

  16. Measuring subjective response to aircraft noise: the effects of survey context.

    PubMed

    Kroesen, Maarten; Molin, Eric J E; van Wee, Bert

    2013-01-01

    In applied research, noise annoyance is often used as indicator of subjective reaction to aircraft noise in residential areas. The present study aims to show that the meaning which respondents attach to the concept of aircraft noise annoyance is partly a function of survey context. To this purpose a survey is conducted among residents living near Schiphol Airport, the largest airport in the Netherlands. In line with the formulated hypotheses it is shown that different sets of preceding questionnaire items influence the response distribution of aircraft noise annoyance as well as the correlational patterns between aircraft noise annoyance and other relevant scales.

  17. Airborne Sunphotometry in Support of the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) Experiment, 2001

    NASA Astrophysics Data System (ADS)

    Redemann, J.; Schmid, B.; Livingston, J. M.; Russell, P. B.; Eilers, J. A.; Hobbs, P. V.; Kahn, R.; Smith, W. L.

    2001-12-01

    As part of the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) experiment, July 10 - August 2, 2001, the 14-channel NASA Ames Airborne Tracking Sunphotometer (AATS-14) was operated successfully aboard the University of Washington CV-580 during 10 research flights, totaling 45.09 flight hours. The CLAMS campaign was a clear sky, shortwave (SW) closure campaign sponsored by CERES, MISR, MODIS-Atmospheres, and the NASA/GEWEX Global Aerosol Climatology Project (GACP), and entailed measurements from the Chesapeake Lighthouse research platform, several land sites, 6 research aircraft and the TERRA satellite. Among the CLAMS research goals were the validation of satellite-based retrievals of aerosol properties, vertical profiles of radiative fluxes, temperature and water vapor. AATS-14 measures the direct solar beam transmission at 14 discrete wavelengths (354-1558 nm), yielding aerosol optical depth (AOD) spectra, columnar water vapor and columnar ozone. Differentiation of AOD (CWV) with respect to altitude in favorable flight patterns, allows the derivation of aerosol extinction (water vapor density). During coordinated flights of the UW CV-580, AATS-14 measured full column aerosol optical depth spectra at exact TERRA overpass time on at least 7 occasions. For five of these opportunities, AOD at 499nm was at or below 0.1. During TERRA overpass time on July 17, 2001, AATS-14 measured the highest AOD encountered during the entire experiment (ca. 0.48 at 499nm), including a horizontal gradient in AOD of more than 0.1 over a horizontal distance of ca. 80 kilometers. In this paper, we will show first sunphotometer-derived results regarding the spatial variation of AOD and CWV during TERRA overpass time at key locations for the CLAMS experiment. Preliminary comparison studies between our AOD/aerosol extinction data and results from (i) extinction products derived using in situ measurements aboard the UW CV-580 and (ii) AOD retrievals using the Multi

  18. Eddy current measurement system evaluation for corrosion depth determination on cast aluminum aircraft structure

    NASA Astrophysics Data System (ADS)

    Singh, Surendra; Greving, Dan; Kinney, Andy; Vensel, Fred; Ohm, Jim; Peeler, Mike

    2013-01-01

    An eddy current (EC) technique was developed to determine the corrosion depth on a bare flange face of a cast aluminum A356-T6 aircraft engine structure. The EC response and the corrosion depths determined through metallurgical cross sections were used to develop an empirical relation between EC response and depth. The EC technique and depth determination are used to inspect the engine structures during overhaul to determine if they are fit for continued service. An accurate and reliable Non-Destructive Inspection is required to ensure that structures returned to service are safe for continued operation. NDE system reliability demonstrations of the eddy current technique are traditionally reported in terms of Probability of Detection (POD) data using MIL-HDBK-1823A. However, the calculation of POD data is based on a simple linear predictive model that is valid only if certain criteria are met. These are: 1) NDE system response is measurable (i.e. continuous data), 2) Flaw size is known and measurable (i.e. continuous data), 3) relationship between the NDE system response and flaw size is linear (or linear on a log scale), 4) variation in measured responseresponse around a predicted response for a given flaw size is normally distributed, 5) the variation around the predicted response is constant (i.e. variation does not change with flaw size), and 6) inherent variability in the NDE system is known and fully understood. In this work, a Measurement System Evaluation (MSE) of the Eddy Current System was used to address some of these concerns. This work was completed on two aircraft structures having varying corrosion depths. The data were acquired in a random manner at fifty regions of interests (ROIs). Three operators participated in this study, and each operator measured Eddy Current response three times in each ROI. In total, there were four hundred and fifty data points collected. Following this, the two structures were sectioned for measuring corrosion depth. The

  19. Perspectives from Meteorological Measurements on High Elevation Ice Caps in the Topical Andes

    NASA Astrophysics Data System (ADS)

    Bradley, R. S.; Hardy, D. R.; Diaz, H. F.

    2008-12-01

    IPCC model simulations show that large temperature changes can be expected in the high mountains of the Tropics due to anthropogenic greenhouse gas increases. Many of these areas are extensively glacierized, and so contain important water resources for the region as a whole. However, the highest mountains are devoid of meteorological measurements, so detection of changes from instrumental records is problematical. This is a critical 'data gap' in the global observing network. In an attempt to remedy this situation, hourly meteorological measurements have been made over the last decade at several high elevation ice cap and glacier sites in the tropical Andes, from Bolivia to Ecuador. These provide insight into contemporary conditions at elevations far above any long-term weather stations. The measurements complement ice core records which suggest that recent changes are unique in the context of the last millennium. We examine the meteorological data and their implications for the interpretation of the ice core records. We also discuss large-scale changes in atmospheric (free air) freezing levels in the Tropics and the factors that control such changes, with implications for the paleo record. Finally, we discuss the recent establishment of a high elevation observing network along the crest of the Tropical Andes, and argue for a Pan-American Cordilleran transect of high mountain meteorological stations, from Alaska to southern Chile.

  20. Airborne Sunphotometer Measurements of Aerosol Optical Depth and Columnar Water Vapor During the Puerto Rico Dust Experiment, and Comparison with Land, Aircraft, and Satellite Measurements

    NASA Technical Reports Server (NTRS)

    Livingston, John M.; Russell, Philip B.; Reid, Jeffrey; Redemann, Jens; Schmid, Beat; Allen, Duane A.; Torres, Omar; Levy, Robert C.; Remer, Lorraine A.; Holben, Brent N.; Hipskind, R. Stephen (Technical Monitor)

    2002-01-01

    Analyses of aerosol optical depth (AOD) and columnar water vapor (CWV) measurements obtained with the six-channel NASA Ames Airborne Tracking Sunphotometer (AATS-6) mounted on a twin-engine aircraft during the summer 2000 Puerto Rico Dust Experiment are presented. In general, aerosol extinction values calculated from AATS-6 AOD measurements acquired during aircraft profiles up to 5 km ASL reproduce the vertical structure measured by coincident aircraft in-situ measurements of total aerosol number and surface area concentration. Calculations show that the spectral dependence of AOD was small (mean Angstrom wavelength exponents of approximately 0.20) within three atmospheric layers defined as the total column beneath the top of each aircraft profile, the region beneath the trade wind inversion, and the region within the Saharan Air Layer (SAL) above the trade inversion. This spectral behavior is consistent with attenuation of incoming solar radiation by large dust particles or by dust plus sea salt. Values of CWV calculated from profile measurements by AATS-6 at 941.9 nm and from aircraft in-situ measurements by a chilled mirror dewpoint hygrometer agree to within approximately 4% (0.13 g/sq cm). AATS-6 AOD values measured on the ground at Roosevelt Roads Naval Air Station and during low altitude aircraft runs over the adjacent Cabras Island aerosol/radiation ground site agree to within 0.004 to 0.030 with coincident data obtained with an AERONET Sun/sky Cimel radiometer located at Cabras Island. For the same observation times, AERONET retrievals of CWV exceed AATS-6 values by a mean of 0.74 g/sq cm (approximately 21 %) for the 2.9-3.9 g/sq cm measured by AATS-6. Comparison of AATS-6 aerosol extinction values obtained during four aircraft ascents over Cabras Island with corresponding values calculated from coincident aerosol backscatter measurements by a ground-based micro-pulse lidar (MPL-Net) located at Cabras yields a similar vertical structure above the trade

  1. CALWATER Overview of the G1 aircraft measurements of cloud-aerosol interactions within winter storms

    NASA Astrophysics Data System (ADS)

    Rosenfeld, D.; Prather, K. A.; Comstock, J. M.; DeMott, P. J.; Cazorla, A.; Chemke, R.; Suski, K.; Freud, E.; Leung, L.

    2011-12-01

    A major component of CalWater 2011 was an aircraft campaign with an extensive suite of cloud physics, aerosol, and trace gases instruments. The aircraft flew nearly 70 hours mainly during winter storms over the Sierra Nevada, Central Valley, the Bay area, coastal range and ocean between 1 Feb and 7 Mar 2011. Some of the unique aspects of this campaign that were the basis for the reported initial findings here were: (1) aerosol time-of flight mass spectrometry (ATOFMS) that provided particle by particle chemical composition; (2) Continuous Flow Diffusion Chamber for detecting ice nuclei; (3) Counterflow virtual impactor (CVI) for sampling the residues of evaporated cloud particles or interstitial aerosol; (4) Cloud drop and hydrometeor probes; (5) 3-D winds and thermodynamic parameters. The aircraft was able to document the clouds from the foothills to the crest of the Sierra Nevada at the section between Sacramento and Fresno during several major winter storms and obtain an unprecedented dataset of the cloud dynamics, microphysics and aerosols during fair weather, atmospheric rivers, barrier jet, pre-frontal, frontal and post frontal conditions. Convective clouds are very often triggered at the foothills of the Sierra Nevada by the start of the rising motion. This triggering is often advanced upwind (westward) due to the blocking effect that is typically associated with a barrier jet. When cloud bases are decoupled from the boundary layer they do not ingest the locally generated aerosols, but rather the pristine air that comes from the ocean. With more southerly back trajectories local decoupling can still bring air pollution from the LA basin, for example. Profound differences in aerosol and cloud microstructure were observed between the coupled and decoupled clouds at the Sierra foothills, where, as expected, the decoupled clouds had a more marine nature. In addition to triggering convective clouds at the foothills, the orographic lifting of the air mass creates

  2. Using Integrated Cavity Output Spectroscopy (ICOS) for Aircraft Measurements of Methane Isotopologues

    NASA Astrophysics Data System (ADS)

    Wilkerson, J. P.; Sayres, D. S.; Healy, C. E.; Munster, J. B.; Dubey, M. K.; Anderson, J. G.

    2014-12-01

    Methane emissions in arctic regions have the potential to contribute a large positive radiative forcing to our climate structure. However, methane in the Arctic has multiple sources and sinks which can complicate source attribution and quantification attempts. In situ stable isotope measurements provide a way to help tease apart different methane sources since the two primary methane sources, thermogenic and biogenic, have distinct isotopic signatures. Ultimately, this knowledge about the ratio between 13CH4 and 12CH4 concentrations can help us understand the relative contribution from each source. The ICOS instrument developed in our lab is an ideal candidate to obtain this type of information. Unlike other measurement methods such as IRMS, our instrument has been tailored to fit in a small aircraft capable of flying below the boundary layer in the arctic region. We flew ICOS in Summer 2013 over the north slope of Alaska and obtained spatially (every 160 m) and temporally (every 2 s) resolved δ13CH4 measurements in real time. Future missions will entail a Stirling-cooled detector in the instrument to further enhance the precision and sensitivity of the measurements. These field missions will enhance our understanding of the routes by which methane is being produced in these regions. This improved knowledge can then lead to improved predictive ability regarding the characteristics of future methane flux and its effect on our climate.

  3. Aircraft measurements of nitrogen dioxide and peroxyacetyl nitrates using luminol chemiluminescence with fast capillary gas chromatography

    SciTech Connect

    Gaffney, J.S.; Marley, N.A.; Steele, H.D.; Drayton, P.J.; Hubbe, J.M.

    1999-10-01

    Fast capillary gas chromatography with luminol detection has been used to make airborne measurements of nitrogen dioxide (NO{sub 2}) and peroxyacetyl nitrate (PAN). The analysis system allows for the simultaneous measurement of NO{sub 2} and peroxyacyl nitrates (PANs) with time resolution of less than 1 min, and improvement of a factor of 4--5 over previously reported methods using electron capture detection. Data presented were taken near Pasco, Washington, in August 1997, during a test flight onboard the US Department of Energy G-1 aircraft. The authors report measurements of NO{sub 2} in the boundary layer in a paper mill plume and a plume from a grass fire, in addition to analyses for free tropospheric NO{sub 2} and PAN. Ratios of PAN/NO{sub 2} were observed to increase with altitude (decreasing temperature) and to reach values of 2--4 above the boundary layer, consistent with the thermal equilibrium of the peroxyacetyl radical and NO{sub 2} and PAN. Estimates for the peroxyacetyl radical in the continental free troposphere, calculated from this equilibrium, were found to be in the range of 10{sup 4}--10{sup 5} molecules per cubic centimeter. These results demonstrate the application of this approach for airborne measurements of NO{sub 2} and PAN in a wide range of field study scenarios.

  4. Effective density measurements of fresh particulate matter emitted by an aircraft engine

    NASA Astrophysics Data System (ADS)

    Abegglen, Manuel; Durdina, Lukas; Mensah, Amewu; Brem, Benjamin; Corbin, Joel; Rindlisbacher, Theo; Wang, Jing; Lohmann, Ulrike; Sierau, Berko

    2014-05-01

    organic aerosols. The soot masses/densities were determined using a DMA-CPMA system as described in the following. The freshly generated soot particles were first charge equilibrated to account for multiple charging and selected according to their mobility size (dm) by a DMA. The monodisperse flow then entered the CPMA which measured the corresponding mass. A condensation particle counter counted the particle number concentration. The effective density (ρeff) can be derived using the fractal relationship between mass and dm and the definition of the effective density. Additionally, we investigated four different laboratory-generated soot types at ETHZ. In detail, a Combustion Aerosol Standard burner ((1) fuel-rich and (2) fuel-lean), a (3) PALAS GFG aerosol generator and (4) carbon black (Cabot Regal Black) from an atomizer, were used. The corresponding results are compared to the aircraft engine exhaust measurements. Results The size, mass, effective density distributions, and the corresponding mobility based fractal dimensions (Dfm) from fresh soot particles emitted by a common aircraft engine and from four laboratory generated soot types were analysed. Dfm is used to describe aggregate particles. It relates the number of primary particles to dm. In general, the effective density decreases with increasing mobility diameter and depends on engine thrust.

  5. Measurements of Young's and shear moduli of rail steel at elevated temperatures.

    PubMed

    Bao, Yuanye; Zhang, Haifeng; Ahmadi, Mehdi; Karim, Md Afzalul; Felix Wu, H

    2014-03-01

    The design and modelling of the buckling effect of Continuous Welded Rail (CWR) requires accurate material constants, especially at elevated temperatures. However, such material constants have rarely been found in literature. In this article, the Young's moduli and shear moduli of rail steel at elevated temperatures are determined by a new sonic resonance method developed in our group. A network analyser is used to excite a sample hanged inside a furnace through a simple tweeter type speaker. The vibration signal is picked up by a Polytec OFV-5000 Laser Vibrometer and then transferred back to the network analyser. Resonance frequencies in both the flexural and torsional modes are measured, and the Young's moduli and shear moduli are determined through the measured resonant frequencies. To validate the measured elastic constants, the measurements have been repeated by using the classic sonic resonance method. The comparisons of obtained moduli from the two methods show an excellent consistency of the results. In addition, the material elastic constants measured are validated by an ultrasound test based on a pulse-echo method and compared with previous published results at room temperature. The measured material data provides an invaluable reference for the design of CWR to avoid detrimental buckling failure.

  6. Extending acoustic data measured with small-scale supersonic model jets to practical aircraft exhaust jets

    NASA Astrophysics Data System (ADS)

    Kuo, Ching-Wen

    2010-06-01

    Modern military aircraft jet engines are designed with variable geometry nozzles to provide optimum thrust in different operating conditions within the flight envelope. However, the acoustic measurements for such nozzles are scarce, due to the cost involved in making full-scale measurements and the lack of details about the exact geometry of these nozzles. Thus the present effort at The Pennsylvania State University and the NASA Glenn Research Center, in partnership with GE Aviation, is aiming to study and characterize the acoustic field produced by supersonic jets issuing from converging-diverging military style nozzles. An equally important objective is to develop a scaling methodology for using data obtained from small- and moderate-scale experiments which exhibits the independence of the jet sizes to the measured noise levels. The experimental results presented in this thesis have shown reasonable agreement between small-scale and moderate-scale jet acoustic data, as well as between heated jets and heat-simulated ones. As the scaling methodology is validated, it will be extended to using acoustic data measured with small-scale supersonic model jets to the prediction of the most important components of full-scale engine noise. When comparing the measured acoustic spectra with a microphone array set at different radial locations, the characteristics of the jet noise source distribution may induce subtle inaccuracies, depending on the conditions of jet operation. A close look is taken at the details of the noise generation region in order to better understand the mismatch between spectra measured at various acoustic field radial locations. A processing methodology was developed to correct the effect of the noise source distribution and efficiently compare near-field and far-field spectra with unprecedented accuracy. This technique then demonstrates that the measured noise levels in the physically restricted space of an anechoic chamber can be appropriately

  7. USE OF REMPI-TOFMS FOR REAL-TIME MEASUREMENT OF TRACE AROMATICS DURING OPERATION OF AIRCRAFT GROUND EQUIPMENT

    EPA Science Inventory

    Emissions of aromatic air toxics from aircraft ground equipment were measured with a resonance enhanced multiphoton ionization—time of flight mass spectrometry (REMPI-TOFMS) system consisting of a pulsed solid state laser for photoionization and a TOFMS for mass discrimination. T...

  8. Volume-imaging lidar observations of the convective structure surrounding the flight path of a flux-measuring aircraft

    NASA Technical Reports Server (NTRS)

    Eloranta, Edwin W.; Forrest, Daniel K.

    1992-01-01

    The University of Wisconsin volume imaging lidar has been used to portray images of the three-dimensional structure of clear air convective plumes in the atmosphere surrounding the flight path of the instrumented Twin Otter aircraft operated by the National Aeronautical Establishment of Canada. Lidar images provide a context for interpretation of the aircraft measurements. The position of data points within a convective element can be determined and the temporal development of the plume can be observed to time the observation with respect to the life cycle of the plume. Plots of the vertical flux of water vapor, superimposed on lidar images clearly demonstrate the well-known sampling difficulties encountered when attempting to measure fluxes near the top of the convective layer. When loran was used to determine average aircraft velocity, flight-leg-averaged horizontal winds measured by the aircraft and area-averaged winds measured by lidar agree to within 0.2 m/s in speed and 1 deg in direction.

  9. Temperature and horizontal wind measurements on the ER-2 aircraft during the 1987 airborne Antarctic ozone experiment

    NASA Technical Reports Server (NTRS)

    Chan, K. Roland; Scott, Stan G.; Bui, T. Paul; Bowen, Stuart W.; Day, Jon

    1988-01-01

    The NASA ER-2 aircraft is equipped with special instrumentation to provide accurate in situ measurement of the atmospheric state variables during flight. The Meteorological Measurement System (MMS) on the ER-2 aircraft is described. Since the meteorological parameters (temperature, pressure, and wind vector) are extensively used by other ER-2 experimenters for data processing and interpretation, the accuracy and resolution of each of these parameters are assessed and discussed. During the 1987 Airborne Antarctic Ozone Experiment (AAOE) mission, the ER-2 aircraft was stationed at Punta Arenas, Chile (53 S, 72 W), and successfully flew over Antarctica on 12 occasions between August 17 and September 22, 1987. On each of the 12 flights, the ER-2 aircraft flight plan was to take off at approximately the same local time, fly southward at a near constant potential temperature surface, descend and ascend at the southernmost terminus at about 72 S over Antarctica and return northward at either the same or a different constant potential temperature surface. The measurements of the MMS experiment during the AAOE mission are presented. MMS data are organized to provide a composite view of the polar atmosphere, which is characterized by frigid temperatures and high zonal winds. Altitudinal variations of the temperature measurement (during takeoff/landing at Punta Arenas and during descent/ascent at the southern terminus) and latitudinal variations of the zonal wind (on near constant potential temperature surfaces) are emphasized and discussed.

  10. Volume-imaging lidar observations of the convective structure surrounding the flight path of a flux-measuring aircraft

    NASA Astrophysics Data System (ADS)

    Eloranta, Edwin W.; Forrest, Daniel K.

    1992-11-01

    The University of Wisconsin volume imaging lidar has been used to portray images of the three-dimensional structure of clear air convective plumes in the atmosphere surrounding the flight path of the instrumented Twin Otter aircraft operated by the National Aeronautical Establishment (NAE) of Canada. Lidar images provide a context for interpretation of the aircraft measurements. The position of data points within a convective element can be determined and the temporal development of the plume can be observed to time the observation with respect to the life cycle of the plume. Plots of the vertical flux of water vapor, q'w', superimposed on lidar images clearly demonstrate the well-known sampling difficulties encountered when attempting to measure fluxes near the top of the convective layer. When Loran was used to determine average aircraft velocity, flight-leg-averaged horizontal winds measured by the aircraft and area-averaged winds measured by lidar agree to within 0.2 m s-1 in speed and 1° in direction.

  11. Estimation of aircraft wake vortex parameters from data measured with a 1.5-μm coherent Doppler lidar.

    PubMed

    Smalikho, I N; Banakh, V A

    2015-07-15

    A strategy of measurement by a 1.5-μm pulsed coherent Doppler lidar "Stream Line" has been developed, and a method for estimation of aircraft wake vortices from the lidar data has been proposed. The principal possibility of obtaining the information about the vortex situation over an airport airfield with the Stream-Line lidar has been demonstrated.

  12. Uncertainty Of The Measurement Of DC Conductivity Of Eramics At Elevated Temperatures

    NASA Astrophysics Data System (ADS)

    Štubňa, Igor; Trnovcová, Viera; Vozár, Libor; Csáki, Štefan

    2015-01-01

    The electrical DC conductivity is measured at room and elevated temperatures on green ceramic samples prepared from kaolin. The arrangement of the sample, with two platinum wire electrodes inserted in the kaolin prism that was used is suitable for measurements of temperature dependences of the DC conductivity from 20 °C to 1100 °C in the air. The uncertainty analysis taking into account thermal expansion of the sample, homogeneity of the temperature field, measurement regime, corrosion of the electrodes, and overlapping of the electrodes is done for 1000 °C. Uncertainties connected with current and voltage measurements and uncertainties connected with the instruments that were used are also considered. The sum of all the partial uncertainties gives an expanded uncertainty of the conductivity measurement. The uncertainty varies with temperature and reaches the value of ˜ 6.5% at 1000 °C.

  13. Measurement of OH, H2SO4, MSA, and HNO3 Aboard the P-3B Aircraft

    NASA Technical Reports Server (NTRS)

    Eisele, F. L.

    2003-01-01

    This paper addresses the measurement of OH, H2SO4, MSA, and HNO3 aboard the P-3B aircraft under the following headings: 1) Performance Report; 2) Highlights of OH, H2SO4, and MSA Measurements Made Aboard the NASA P-3B During TRACE-P; 3) Development and characteristics of an airborne-based instrument used to measure nitric acid during the NASA TRACE-P field experiment.

  14. Smart skin technology development for measuring ice accretion, stall, and high AOA aircraft performance. Part 1: Capacitive ice detector development

    NASA Technical Reports Server (NTRS)

    Pruzan, Daniel A.; Khatkhate, Ateen A.; Gerardi, Joseph J.; Hickman, Gail A.

    1993-01-01

    A reliable way to detect and measure ice accretion during flight is required to reduce the hazards of icing currently threatening present day aircraft. Many of the sensors used for this purpose are invasive (probe) sensors which must be placed in areas of the airframe where ice does not naturally form. Due to the difference in capture efficiency of the exposed surface, difficulties result in correlating the ice accretion on the probe to what is happening on a number of vastly different airfoil sections. Most flush mounted sensors in use must be integrated into the aircraft surface by cutting or drilling the aircraft surface. An alternate type of ice detector which is based on a NASA patent is currently being investigated at Innovative Dynamics, Inc. (IDI). Results of the investigation into the performance of different capacitive type sensor designs, both rigid as well as elastic, are presented.

  15. In-flight measurements of aircraft propeller deformation by means of an autarkic fast rotating imaging system

    NASA Astrophysics Data System (ADS)

    Stasicki, Boleslaw; Boden, Fritz

    2015-03-01

    The non-intrusive in-flight measurement of the deformation and pitch of the aircraft propeller is a demanding task. The idea of an imaging system integrated and rotating with the aircraft propeller has been presented on the 30th International Congress on High-Speed Imaging and Photonics (ICHSIP30) in 2012. Since then this system has been constructed and tested in the laboratory as well as on the real aircraft. In this paper we outline the principle of Image Pattern Correlation Technique (IPCT) based on Digital Image Correlation (DIC) and describe the construction of a dedicated autarkic 3D camera system placed on the investigated propeller and rotating at its full speed. Furthermore, the results of the first ground and in-flight tests are shown and discussed. This development has been found by the European Commission within the 7th frame project AIM2 (contract no. 266107).

  16. An intercomparison of aircraft instrumentation for tropospheric measurements of carbonyl sulfide, hydrogen sulfide, and carbon disulfide

    NASA Technical Reports Server (NTRS)

    Gregory, Gerald L.; Davis, Douglas D.; Thornton, Donald C.; Johnson, James E.; Bandy, Alan R.; Saltzman, Eric S.; Andreae, Meinrat O.; Barrick, John D.

    1993-01-01

    This paper reports results of NASA's Chemical Instrumentation and Test Evaluation (CITE 3) during which airborne measurements for carbonyl sulfide (COS), hydrogen sulfide (H2S), and carbon disulfide (CS2) were intercompared. Instrumentation included a gas chromatograph using flame photometric detection (COS, H2S, and CS2), a gas chromatograph using mass spectrometric detection (COS) and CS2), a gas chromatograph using fluorination and subsequent SF6 detection via electron capture (COS and CS2), and the Natusch technique (H2S). The measurements were made over the Atlantic Ocean east of North and South America during flights from NASA's Wallops Flight Center, Virginia, and Natal, Brazil, in August/September 1989. Most of the intercomparisons for H2S and CS2 were at mixing ratios less than 25 pptv and less than 10 pptv, respectively, with a maximum mixing ratio of about 100 pptv and 50 pptv, respectively. Carbonyl sulfide intercomparisons were at mixing ratios between 400 and 600 pptv. Measurements were intercompared from data bases constructed from time periods of simultaneous or overlapping measurements. Agreement among the COS techniques averaged about 5%, and individual measurements were generally within 10%. For H2S and at mixing ratio greater than 25 pptv, the instruments agreed on average to about 15%. At mixing ratios less than 25 pptv the agreement was about 5 pptv. For CS2 (mixing ratios less than 50 pptv), two techniques agreed on average to about 4 pptv, and the third exhibited a bias (relative to the other two) that varied in the range of 3-7 pptv. CS2 mixing ratios over the ocean east of Natal as measured by the gas chromatograph-mass spectrometer technique were only a few pptv and were below the detection limits of the other two techniques. The CITE 3 data are used to estimate the current uncertainty associated with aircraft measurements of COS, H2S, and CS2 in the remote troposphere.

  17. Characterization of a Quadrotor Unmanned Aircraft System for Aerosol-Particle-Concentration Measurements.

    PubMed

    Brady, James M; Stokes, M Dale; Bonnardel, Jim; Bertram, Timothy H

    2016-02-02

    High-spatial-resolution, near-surface vertical profiling of atmospheric chemical composition is currently limited by the availability of experimental platforms that can sample in constrained environments. As a result, measurements of near-surface gradients in trace gas and aerosol particle concentrations have been limited to studies conducted from fixed location towers or tethered balloons. Here, we explore the utility of a quadrotor unmanned aircraft system (UAS) as a sampling platform to measure vertical and horizontal concentration gradients of trace gases and aerosol particles at high spatial resolution (1 m) within the mixed layer (0-100 m). A 3D Robotics Iris+ autonomous quadrotor UAS was outfitted with a sensor package consisting of a two-channel aerosol optical particle counter and a CO2 sensor. The UAS demonstrated high precision in both vertical (±0.5 m) and horizontal positions (±1 m), highlighting the potential utility of quadrotor UAS drones for aerosol- and trace-gas measurements within complex terrain, such as the urban environment, forest canopies, and above difficult-to-access areas such as breaking surf. Vertical profiles of aerosol particle number concentrations, acquired from flights conducted along the California coastline, were used to constrain sea-spray aerosol-emission rates from coastal wave breaking.

  18. Aircraft measurements of ammonia and nitric acid in the lower troposphere

    NASA Astrophysics Data System (ADS)

    Lebel, P. J.; Hoell, J. M.; Levine, J. S.; Vay, S. A.

    1985-06-01

    The first simultaneous measurements of ammonia and nitric acid in the troposphere have been made from an aircraft using a tungsten oxide denuder system. Vertical profiles of NH3 and HNO3 taken over coastal Virginia and Maryland in March and September, 1983, at altitudes from 150 m to 3000 m, show mixing ratios that decrease with altitude. Ammonia profiles show substantial seasonal variation, while nitric acid profiles do not. Using the measured profiles and a one-dimensional photochemical model, lifetimes due to heterogeneous loss of one day for HNO3 and ten days for NH3 are calculated. In contrast, NH3 profiles up to 5300 m over the North Atlantic Ocean during August 1982 show mixing ratios that increase slightly with altitude. These data represent the first ammonia profiles measured over the ocean. It is suggested that the increase in NH3 with altitude is a result of an ammonia-rich continental air mass advected over the ocean, followed by the dissolution of NH3 in the marine boundary layer on water-covered sea salt particles.

  19. Carbon balance of China constrained by CONTRAIL aircraft CO2 measurements

    NASA Astrophysics Data System (ADS)

    Jiang, F.; Wang, H. M.; Chen, J. M.; Machida, T.; Zhou, L. X.; Ju, W. M.; Matsueda, H.; Sawa, Y.

    2014-03-01

    Terrestrial CO2 flux estimates in China using atmospheric inversion method are beset with considerable uncertainties because very few atmospheric CO2 concentration measurements are available. In order to improve these estimates, nested atmospheric CO2 inversion during 2002-2008 is performed in this study using passenger aircraft-based CO2 measurements over Eurasia from the Comprehensive Observation Network for Trace gases by Airliner (CONTRAIL) project. The inversion system includes 43 regions with a focus on China, and is based on the Bayesian synthesis approach and the TM5 transport model. The terrestrial ecosystem carbon flux modeled by the BEPS model and the ocean exchange simulated by the OPA-PISCES-T model are considered as the prior fluxes. The impacts of CONTRAIL CO2 data on inverted China terrestrial carbon fluxes are quantified, the improvement of the inverted fluxes after adding CONTRAIL CO2 data are rationed against climate factors and evaluated by comparing the simulated atmospheric CO2 concentrations with three independent surface CO2 measurements in China. Results show that with the addition of CONTRAIL CO2 data, the inverted carbon sink in China increases while those in South and Southeast Asia decrease. Meanwhile, the posterior uncertainties over these regions are all reduced. CONTRAIL CO2 data also have a large effect on the inter-annual variation of carbon sinks in China, leading to a better correlation between the carbon sink and the annual mean climate factors. Evaluations against the CO2 measurements at three sites in China also show that the CONTRAIL CO2 measurements have improved the inversion results.

  20. Carbon balance of China constrained by CONTRAIL aircraft CO2 measurements

    NASA Astrophysics Data System (ADS)

    Jiang, F.; Wang, H. M.; Chen, J. M.; Machida, T.; Zhou, L. X.; Ju, W. M.; Matsueda, H.; Sawa, Y.

    2014-09-01

    Terrestrial carbon dioxide (CO2) flux estimates in China using atmospheric inversion method are beset with considerable uncertainties because very few atmospheric CO2 concentration measurements are available. In order to improve these estimates, nested atmospheric CO2 inversion during 2002-2008 is performed in this study using passenger aircraft-based CO2 measurements over Eurasia from the Comprehensive Observation Network for Trace gases by Airliner (CONTRAIL) project. The inversion system includes 43 regions with a focus on China, and is based on the Bayesian synthesis approach and the TM5 transport model. The terrestrial ecosystem carbon flux modeled by the Boreal Ecosystems Productivity Simulator (BEPS) model and the ocean exchange simulated by the OPA-PISCES-T model are considered as the prior fluxes. The impacts of CONTRAIL CO2 data on inverted China terrestrial carbon fluxes are quantified, the improvement of the inverted fluxes after adding CONTRAIL CO2 data are rationed against climate factors and evaluated by comparing the simulated atmospheric CO2 concentrations with three independent surface CO2 measurements in China. Results show that with the addition of CONTRAIL CO2 data, the inverted carbon sink in China increases while those in South and Southeast Asia decrease. Meanwhile, the posterior uncertainties over these regions are all reduced (2-12%). CONTRAIL CO2 data also have a large effect on the inter-annual variation of carbon sinks in China, leading to a better correlation between the carbon sink and the annual mean climate factors. Evaluations against the CO2 measurements at three sites in China also show that the CONTRAIL CO2 measurements may have improved the inversion results.

  1. Aeroacoustic Study of a High-Fidelity Aircraft Model: Part 1- Steady Aerodynamic Measurements

    NASA Technical Reports Server (NTRS)

    Khorrami, Mehdi R.; Hannon, Judith A.; Neuhart, Danny H.; Markowski, Gregory A.; VandeVen, Thomas

    2012-01-01

    In this paper, we present steady aerodynamic measurements for an 18% scale model of a Gulfstream air-craft. The high fidelity and highly-instrumented semi-span model was developed to perform detailed aeroacoustic studies of airframe noise associated with main landing gear/flap components and gear-flap interaction noise, as well as to evaluate novel noise reduction concepts. The aeroacoustic tests, being conducted in the NASA Langley Research Center 14- by 22-Foot Subsonic Tunnel, are split into two entries. The first entry, completed November 2010, was entirely devoted to the detailed mapping of the aerodynamic characteristics of the fabricated model. Flap deflections of 39?, 20?, and 0? with the main landing gear on and off were tested at Mach numbers of 0.16, 0.20, and 0.24. Additionally, for each flap deflection, the model was tested with the tunnel both in the closed-wall and open-wall (jet) modes. During this first entry, global forces (lift and drag) and extensive steady and unsteady surface pressure measurements were obtained. Preliminary analysis of the measured forces indicates that lift, drag, and stall characteristics compare favorably with Gulfstream?s high Reynolds number flight data. The favorable comparison between wind-tunnel and flight data allows the semi-span model to be used as a test bed for developing/evaluating airframe noise reduction concepts under a relevant environment. Moreover, initial comparison of the aerodynamic measurements obtained with the tunnel in the closed- and open-wall configurations shows similar aerodynamic behavior. This permits the acoustic and off-surface flow measurements, planned for the second entry, to be conducted with the tunnel in the open-jet mode.

  2. Comparison of CMAQ Modeling Study with Discover-AQ 2014 Aircraft Measurements over Colorado

    NASA Astrophysics Data System (ADS)

    Tang, Y.; Pan, L.; Lee, P.; Tong, D.; Kim, H. C.; Artz, R. S.

    2014-12-01

    NASA and NCAR jointly led a recent multiple platform-based (space, air and ground) measurement intensive to study air quality and to validate satellite data. The Discover-AQ/FRAPPE field experiment took place along the Colorado Front Range in July and August, 2014. The air quality modeling team of the NOAA Air Resources Laboratory was one of the three teams that provided real-time air quality forecasting for the campaign. The U.S. EPA Community Multi-scale Air Quality (CMAQ) Model was used with emission inventories based on the data set used by the NOAA National Air Quality Forecasting Capacity (NAQFC). By analyzing the forecast results calculated using aircraft measurements, it was found that CO emissions tended to be overestimated, while ethane emissions were underestimated. Biogenic VOCs were also underpredicted. Due to their relatively high altitude, ozone concentrations in Denver and the surrounding areas are affected by both local emissions and transported ozone. The modeled ozone was highly dependent on the meteorological predictions over this region. The complex terrain over the Rocky Mountains also contributed to the model uncertainty. This study discussed the causes of model biases, the forecast performance under different meteorology, and results from using different model grid resolutions. Several data assimilation techniques were further tested to improve the "post-analysis" performance of the modeling system for the period.

  3. Aircraft measurements of nitrogen dioxide and peroxyacyl nitrates using luminol chemiluminescence with fast capillary gas chromatography

    SciTech Connect

    Gaffney, J.S.; Marley, N.A.; Drayton, P.J.

    1997-09-01

    Peroxyacyl nitrates (PANs) and nitrogen dioxide (NO{sub 2}) are important trace gas species associated with photochemical air pollution. The PANs are in thermal equilibrium with the peroxyacetyl radical and NO{sub 2}. Because PANs are trapped peroxy radicals, they are an important indicator species of the photochemical age of an air parcel, as well as being a means of long-range transporting of NO{sub 2}, leading to the formation of regional ozone and other oxidants. Typically, PANs are measured by using a gas chromatograph with electron-capture detection (ECD). Once automated, this method has been shown to be reliable and quite sensitive, allowing the levels of PANs to be measured at low parts per trillion in the troposphere. Unfortunately, a number of other atmospheric gases also have strong ECD signals or act as inferences and limit the speed in which the analysis can be completed. Currently, the shortest analysis time for PAN is approx. 5 minutes with ECD. The authors recent examined the luminol detection of NO{sub 2} and PANs using gas capillary chromatography for rapid monitoring of these important trace gases. Analysis of the PANs (PAN, PPN, and PBN) and NO{sub 2} in one minute has been demonstrated in laboratory studies by using this approach. Reported here are modifications of this instrument for aircraft operation and preliminary results from test flights taken near Pasco, Washington in August of 1997.

  4. A Model-Based Anomaly Detection Approach for Analyzing Streaming Aircraft Engine Measurement Data

    NASA Technical Reports Server (NTRS)

    Simon, Donald L.; Rinehart, Aidan Walker

    2015-01-01

    This paper presents a model-based anomaly detection architecture designed for analyzing streaming transient aircraft engine measurement data. The technique calculates and monitors residuals between sensed engine outputs and model predicted outputs for anomaly detection purposes. Pivotal to the performance of this technique is the ability to construct a model that accurately reflects the nominal operating performance of the engine. The dynamic model applied in the architecture is a piecewise linear design comprising steady-state trim points and dynamic state space matrices. A simple curve-fitting technique for updating the model trim point information based on steadystate information extracted from available nominal engine measurement data is presented. Results from the application of the model-based approach for processing actual engine test data are shown. These include both nominal fault-free test case data and seeded fault test case data. The results indicate that the updates applied to improve the model trim point information also improve anomaly detection performance. Recommendations for follow-on enhancements to the technique are also presented and discussed.

  5. A Model-Based Anomaly Detection Approach for Analyzing Streaming Aircraft Engine Measurement Data

    NASA Technical Reports Server (NTRS)

    Simon, Donald L.; Rinehart, Aidan W.

    2014-01-01

    This paper presents a model-based anomaly detection architecture designed for analyzing streaming transient aircraft engine measurement data. The technique calculates and monitors residuals between sensed engine outputs and model predicted outputs for anomaly detection purposes. Pivotal to the performance of this technique is the ability to construct a model that accurately reflects the nominal operating performance of the engine. The dynamic model applied in the architecture is a piecewise linear design comprising steady-state trim points and dynamic state space matrices. A simple curve-fitting technique for updating the model trim point information based on steadystate information extracted from available nominal engine measurement data is presented. Results from the application of the model-based approach for processing actual engine test data are shown. These include both nominal fault-free test case data and seeded fault test case data. The results indicate that the updates applied to improve the model trim point information also improve anomaly detection performance. Recommendations for follow-on enhancements to the technique are also presented and discussed.

  6. PM emissions measurements of in-service commercial aircraft engines during the Delta-Atlanta Hartsfield Study

    NASA Astrophysics Data System (ADS)

    Lobo, Prem; Hagen, Donald E.; Whitefield, Philip D.; Raper, David

    2015-03-01

    This paper describes the results of the physical characterization of aircraft engine PM emission measurements conducted during the Delta-Atlanta Hartsfield Study at the Hartsfield-Jackson Atlanta International Airport. Engine exit plane PM emissions were sampled from on-wing engines on several in-service commercial transport aircraft from the fleet of Delta Airlines. The size distributions were lognormal in nature with a single mode. The geometric mean diameter was found to increase with increasing engine thrust, ranging from 15 nm at idle to 40 nm at takeoff. PM number- and mass-based emission indices were observed to be higher at the idle conditions (4% and 7%), lowest at 15%-30% thrust, and then increase with increasing thrust. Emissions measurements were also conducted during an advected plume study where over 300 exhaust plumes generated by a broad mix of commercial transports were sampled 100-350 m downwind from aircraft operational runways during normal airport operations. The range of values measured at take-off for the different engine types in terms of PM number-based emission index was between 7 × 1015-9 × 1017 particles/kg fuel burned, and that for PM mass-based emission index was 0.1-0.6 g/kg fuel burned. PM characteristics of aircraft engine specific exhaust were found to evolve over time as the exhaust plume expands, dilutes with ambient air, and cools. The data from these measurements will enhance the emissions inventory development for a subset of engines operating in the commercial fleet and improve/validate current environmental impact predictive tools with real world aircraft engine specific PM emissions inputs.

  7. Examination of the Lateral Attenuation of Aircraft Noise

    NASA Technical Reports Server (NTRS)

    Plotkin, Kenneth J.; Hobbs, Christopher M.; Bradley, Kevin A.; Shepherd, Kevin P. (Technical Monitor)

    2000-01-01

    Measurements of the lateral attenuation of noise from aircraft operations at Denver International Airport were made at distances up to 2000 feet and elevation angles up to 27 degrees. Attenuation Calculated from modem ground impedance theory agrees well with average measured attenuation. The large variability between measured and predicted levels observed at small elevation angles is demonstrated to be due to refraction by wind and temperature gradients.

  8. Sulfuric acid measurements in the exhaust plume of a jet aircraft in flight: Implications for the sulfuric acid formation efficiency

    NASA Astrophysics Data System (ADS)

    Curtius, J.; Arnold, F.; Schulte, P.

    2002-04-01

    Sulfuric acid concentrations were measured in the exhaust plume of a B737-300 aircraft in flight. The measurements were made onboard of the German research aircraft Falcon using the Volatile Aerosol Component Analyzer (VACA). The VACA measures total H2SO4, which is the sum of gaseous H2SO4 and aerosol H2SO4. Measurements took place at distances of 25-200 m behind the B737 corresponding to plume ages of about 0.1-1 seconds. The fuel sulfur content (FSC) of the fuel burned by the B737 engines was alternatively 2.6 and 56 mg sulfur per kilogram fuel (ppmm). H2SO4 concentrations measured in the plume for the 56 ppmm sulfur case were up to ~600 pptv. The average concentration of H2SO4 measured in the ambient atmosphere outside the aircraft plume was 88 pptv, the maximum ambient atmospheric H2SO4 was ~300 pptv. Average efficiencies ɛΔCO2 = 3.3 +/- 1.8% and ɛΔT = 2.9 +/- 1.6% for fuel sulfur conversion to sulfuric acid were inferred when relating the H2SO4 data to measurements of the plume tracers ΔCO2 and ΔT.

  9. A snapshot of the UK net greenhouse gas flux using a mass balance approach with aircraft measurements

    NASA Astrophysics Data System (ADS)

    Allen, G.; Pitt, J. R.; Palmer, P. I.; Percival, C.; Mead, M. I.; Lee, J. D.; Le Breton, M. R.

    2015-12-01

    We present airborne observations of high-precision in-situ and remotely sensed CO2, CH4 and other trace gases made from the NERC Facility for Airborne Atmospheric Measurement (FAAM) BAe-146 research aircraft during Spring and Summer months in 2014 and 2015. Measurements were recorded during the GAUGE (Greenhouse gAs Uk and Global Emissions) aircraft field campaign, based out of Cranfield, UK, with sampling around and over the UK Mainland and Ireland. We derive Lagrangian mass-balanced net surface fluxes of CO2, CH4, CO, and N2O from a large surface footprint of England based on data collected during a flight in May 2015 by combining in-situ and remote-sensed concentration measurements and measured boundary layer thermodynamic profiles. By employing an advective box model for the volume enclosed by the flight-tracks and combining aircraft-measured winds and along-track Lagrangian back-trajectory modelling, we examine the sensitivity of total flux uncertainty to atmospheric transport and measurement errors using error propagation implicit in the mass balancing method. Finally, we compare the measured snapshot net fluxes to those reported in the current UK emissions inventory (weighted for surface footprint) and to previous UK-regional greenhouse gas top-down assessments.

  10. Elevated temperature crack growth

    NASA Technical Reports Server (NTRS)

    Yau, J. F.; Malik, S. N.; Kim, K. S.; Vanstone, R. H.; Laflen, J. H.

    1985-01-01

    The objective of the Elevated Temperature Crack Growth Project is to evaluate proposed nonlinear fracture mechanics methods for application to combustor liners of aircraft gas turbine engines. During the first year of this program, proposed path-independent (P-I) integrals were reviewed for such applications. Several P-I integrals were implemented into a finite-element postprocessor which was developed and verified as part of the work. Alloy 718 was selected as the analog material for use in the forthcoming experimental work. A buttonhead, single-edge notch specimen was designed and verified for use in elevated-temperature strain control testing with significant inelastic strains. A crack mouth opening displacement measurement device was developed for further use.

  11. Estimation and Propagation of Errors in Ice Sheet Bed Elevation Measurements

    NASA Astrophysics Data System (ADS)

    Johnson, J. V.; Brinkerhoff, D.; Nowicki, S.; Plummer, J.; Sack, K.

    2012-12-01

    This work is presented in two parts. In the first, we use a numerical inversion technique to determine a "mass conserving bed" (MCB) and estimate errors in interpolation of the bed elevation. The MCB inversion technique adjusts the bed elevation to assure that the mass flux determined from surface velocity measurements does not violate conservation. Cross validation of the MCB technique is done using a subset of available flight lines. The unused flight lines provide data to compare to, quantifying the errors produced by MCB and other interpolation methods. MCB errors are found to be similar to those produced with more conventional interpolation schemes, such as kriging. However, MCB interpolation is consistent with the physics that govern ice sheet models. In the second part, a numerical model of glacial ice is used to propagate errors in bed elevation to the kinematic surface boundary condition. Initially, a control run is completed to establish the surface velocity produced by the model. The control surface velocity is subsequently used as a target for data inversions performed on perturbed versions of the control bed. The perturbation of the bed represents the magnitude of error in bed measurement. Through the inversion for traction, errors in bed measurement are propagated forward to investigate errors in the evolution of the free surface. Our primary conclusion relates the magnitude of errors in the surface evolution to errors in the bed. By linking free surface errors back to the errors in bed interpolation found in the first part, we can suggest an optimal spacing of the radar flight lines used in bed acquisition.

  12. Measurement of OH, H2SO4, MSA, NH3 and DMSO Aboard the NASA P-3B Aircraft

    NASA Technical Reports Server (NTRS)

    Eisele, Fred

    2001-01-01

    This project involved the installation of a downsized multichannel mass spectrometer instrument on the NASA P-3B aircraft and its subsequent use on the PEM-Tropics B mission. The new instrument performed well, measuring a number of difficult-to-measure compounds and providing much new photochemical and sulfur data as well as possibly uncovering a new nighttime DMSO source. The details of this effort are discussed.

  13. Aircraft measured atmospheric momentum, heat and radiation fluxes over Arctic sea ice

    NASA Astrophysics Data System (ADS)

    Hartmann, Jörg; Kottmeier, Christoph; Wamser, Christian; Augstein, Ernst

    The vertical turbulent momentum, sensible and latent heat fluxes and the surface radiation balance are derived from measurements of low level flights (<50 m height) with a highly instrumented aircraft over Fram Strait in September/October 1991. High resolution information on the sea ice cover is obtained with a digital line scan camera. It is found that the drag coefficient for neutral static stability at 10 m height can be composed of a skin drag (cdns = 1.1 . 10-3), which coincides with the open water value, and a form drag which linearly increases with the mean ice area perpendicular to the surface wind vector per unit surface area. The ratio of the generally small sensible and latent heat fluxes (both ≤ 20 Wm-2) is close to unity for near neutral atmospheric stratification and no dependence of these fluxes on sea ice concentration can be detected, at least for the encountered ice concentrations larger than 50%. Measurements at about 40 m height are not sufficient to study cases with stable stratification since the flight level seems to be fully decoupled from the surface processes. In this autumn measurements 50% to 90% of the net energy flux at the surface is made up by the radiation balance. Therefore, radiative fluxes form important components in polar air-sea exchange processes. The long wave downward radiation can be parameterised using the ɛσT4 law with the near surface air temperature and the empirically determined values for the emissivity ɛ = 0.71 and ɛ = 0.90 for clear and cloudy skies, respectively. The standard deviations of our measurements from this parameterisation are 4.6 Wm-2 for clear and 8.6 Wm-2 for cloudy skies. These values fall into the range ofthe instrumental uncertainty.

  14. Aerosol measurements at a high-elevation site: composition, size, and cloud condensation nuclei activity

    SciTech Connect

    Friedman, Beth; Zelenyuk, Alla; Beranek, Josef; Kulkarni, Gourihar R.; Pekour, Mikhail S.; Hallar, Anna G.; McCubbin, Ian; Thornton, Joel A.; Cziczo, D. J.

    2013-12-09

    We present measurements of CCN concentrations and associated aerosol composition and size properties at a high-elevation research site in March 2011. CCN closure and aerosol hygroscopicity were assessed using simplified assumptions of bulk aerosol properties as well as a new method utilizing single particle composition and size to assess the importance of particle mixing state in CCN activation. Free troposphere analysis found no significant difference between the CCN activity of free tropospheric aerosol and boundary layer aerosol at this location. Closure results indicate that using only size and number information leads to adequate prediction, in the majority of cases within 50%, of CCN concentrations, while incorporating the hygroscopicity parameters of the individual aerosol components measured by single particle mass spectrometry adds to the agreement, in most cases within 20%, between predicted and measured CCN concentrations. For high-elevation continental sites, with largely aged aerosol and low amounts of local area emissions, a lack of chemical knowledge and hygroscopicity may not hinder models in predicting CCN concentrations. At sites influenced by fresh emissions or more heterogeneous particle types, single particle composition information may be more useful in predicting CCN concentrations and understanding the importance of particle mixing state on CCN activation.

  15. New measurements of multilayer insulation at variable cold temperature and elevated residual gas pressure

    NASA Astrophysics Data System (ADS)

    Funke, Th; Haberstroh, Ch

    2015-12-01

    New MLI measurements at the TU Dresden flow type calorimeter have been carried out. Specimens of 20 layer double side aluminized polyester film were tested. A cylindrical cold surface of 0.9 m2 is held at the desired cold boundary temperature between approximately 30 K and 300 K. The heat transfer through the MLI is measured by recording the mass flow as well as the inlet and the outlet temperature of the cooling fluid. Measurements at varied cold boundary temperatures have been performed. Moreover the effect of an additional vacuum degradation - as it might occur by decreasing getter material performance in real systems at elevated temperatures - is studied by a controlled inlet of nitrogen gas. Thus the vacuum pressure was varied over a range of 10-7 mbar to 10-2 mbar. Different cold boundary temperatures between 35 K and 110 K were investigated. Test results for 20 layer MLI are presented.

  16. Aircraft-based measurements for the identification and quantification of sources and sinks in the carbon cycle

    NASA Astrophysics Data System (ADS)

    Caulton, Dana R.

    Improved quantification of carbon-cycle sources and sinks is an important requirement for determining mitigation strategies and modeling future climate interactions. Analytically robust measurements require high-precision instrumentation and thoughtful experimental design to produce rigorous and reproducible results despite complex and quickly changing meteorological and environmental conditions. Here, an aircraft platform equipped with a high-precision cavity ring-down spectrometer for CO2, CH4 and H2O quantification was used to acquire data from previously un-sampled sources. The aircraft mass-balance technique was used to quantify CH4 emissions from natural gas well pads in the drilling stage, which were 2-3 orders of magnitude higher than previous estimates of emissions from this stage. In addition, the first in-situ flare emission data was collected for natural gas flares in North Dakota, Pennsylvania and Texas. Flare efficiency was high for most flares, higher than assumed efficiency. However, a few flares sampled with lower efficiencies closer to the assumed flare efficiency suggest the need for characterization of operational conditions specific to operators and basins. Finally, eddy-covariance O2 and heat fluxes were measured over three east-coast forests at sites close to and far from surface eddy-covariance towers. Tower data is often used in models to represent a larger heterogeneous region. Aircraft and tower O2 and sensible heat flux agreed well, indicating that for these sites, tower data is a good approximation of the larger region, though significant variability was observed. Aircraft latent heat fluxes were routinely much larger that tower fluxes, most likely due to the influence of advection which is measured by the aircraft eddy-covariance technique, but not by towers.

  17. An aircraft instrument design for in situ tropospheric OH measurements by laser induced fluorescence at low pressures

    NASA Technical Reports Server (NTRS)

    Brune, William H.; Stevens, Philip S.; Mather, James H.

    1993-01-01

    The hydroxyl radical (OH) is important for many processes involved in tropospheric chemistry. For instance, it initiates the photochemical degradation of gases that cause global climate change, such as methane and the chlorofluorocarbon substitutes (HCFCs). Because of its reactivity, its abundances are less than 0.1 pptv. Thus, OH has been very difficult to measure accurately, despite its importance. Techniques have evolved, however, so that good measurements of tropospheric OH abundances are now possible. One of these techniques that is adaptable to aircraft measurements is the laser induced fluorescence detection of the OH radical in a detection chamber at low pressures. The current ground-based instrument, which can be readily adapted to aircraft, can detect OH abundances of 1.4 x 10 exp 5 OH molecules/cu cm with S/N = 2 in 30 sec, and 5 x 10 exp 4/cu cm in 5 min.

  18. Flux measurements by the NRC Twin Otter atmospheric research aircraft: 1987-2011

    NASA Astrophysics Data System (ADS)

    Desjardins, Raymond L.; Worth, Devon E.; MacPherson, J. Ian; Bastian, Matthew; Srinivasan, Ramesh

    2016-03-01

    Over the past 30 years, the Canadian Twin Otter research group has operated an aircraft platform for the study of atmospheric greenhouse gas fluxes (carbon dioxide, ozone, nitrous oxide and methane) and energy exchange (latent and sensible heat) over a wide range of terrestrial ecosystems in North America. Some of the acquired data from these projects have now been archived at the Flight Research Laboratory and Agriculture and Agri-Food Canada. The dataset, which contains the measurements obtained in eight projects from 1987 to 2011 are now publicly available. All these projects were carried out in order to improve our understanding of the biophysical controls acting on land-surface atmosphere fluxes. Some of the projects also attempted to quantify the impacts of agroecosystems on the environment. To provide information on the data available, we briefly describe each project and some of the key findings by referring to previously published relevant work. As new flux analysis techniques are being developed, we are confident that much additional information can be extracted from this unique data set.

  19. Aircraft measurement of glyoxal (CHOCHO) over southeast U.S. during SENEX2013

    NASA Astrophysics Data System (ADS)

    Min, K.; Dube, W. P.; Washenfelder, R. A.; Langford, A. O.; Brown, S. S.; Aikin, K.; Bougiatioti, A.; Brock, C. A.; De Gouw, J. A.; Edwards, P. M.; Gilman, J.; Graus, M.; Hanisco, T. F.; Holloway, J.; Kaiser, J.; Keutsch, F. N.; Lee, B. H.; Lerner, B. M.; Liao, J.; Lin, J. J.; Lopez-Hilfiker, F.; Middlebrook, A. M.; Nenes, A.; Peischl, J.; Pollack, I. B.; Roberts, J. M.; Ryerson, T. B.; Thornton, J. A.; Veres, P. R.; Warneke, C.

    2013-12-01

    Glyoxal (CHOCHO) is an indicator of the oxidation processes of volatile organic compounds (VOCs) in atmosphere. It has been proposed to play an important role in secondary organic aerosol formation due to its high water solubility and ability to form oligomers. Owing to the difficulties in CHOCHO detection, there are no previous in-situ data available from aircraft. In support of the scientific goals of SENEX 2013 (Studying the Interactions Between Natural and Anthropogenic Emissions at the Nexus of Climate Change and Air Quality) to investigate the role of anthropogenic and natural emissions in ozone and aerosol formation and their climate impact, we developed and deployed the Airborne Cavity Enhanced Spectrometer (ACES) for rapid, sensitive in situ measurements of CHOCHO and other trace gases. We examine the geographical distribution of glyoxal across a range of air masses influenced by both biogenic and anthropogenic emissions in the southeastern US. The contrast between these air masses, together with model calculations of VOC degradation mechanisms, allow us to assess glyoxal's sources from oxidation of different VOCs and its sinks, including photochemical degradation and aerosol uptake. Andre Welti1, 2 and Glenn M. Wolfe4, * are not named on the author list due to the maximum limit. *: University of Maryland Baltimore County-Joint Center for Earth Systems Technology

  20. Measurements in Vortex Wakes Shed by Conventional and Modified Subsonic Aircraft

    NASA Technical Reports Server (NTRS)

    Rossow, Vernon J.

    1996-01-01

    A theoretical and experimental program is underway at NASA Ames Research Center to first obtain a better understanding of the hazard posed by the vortex wakes of subsonic transports, and then to develop methods on how to modify the wake-generating aircraft in order to make the vortices less hazardous. This paper summarizes results obtained in the 80- by 120-Foot Wind Tunnel at NASA Ames Research Center on the characteristics of the vortex wakes that trail from 0.03 scale models of a B-747 and of a DC-10. Measurements are first described that were taken in the wakes with a hot-film anemometer probe, and with wings that range in size from 0.2 to 1.0 times the span of the wake generating models at downstream distances of 81 ft and 162 ft. behind the wake-generating model; i.e., at scale distances of 0.5 and 1.0 mile. The data are then used to evaluate the accuracy of a vortex-lattice method for prediction of the loads induced on following wings by vortex wakes.

  1. Carbon flux estimation for Siberia by inverse modeling constrained by aircraft and tower CO2 measurements

    NASA Astrophysics Data System (ADS)

    Saeki, T.; Maksyutov, S.; Sasakawa, M.; Machida, T.; Arshinov, M.; Tans, P. P.; Conway, T. J.; Saito, M.; Valsala, V.; Oda, T.; Andres, R. J.

    2012-12-01

    Despite Siberian ecosystems being one of the largest carbon reservoirs in the world, the Siberian carbon sink remains poorly understood due to the limited numbers of observations. We present the first results of atmospheric CO2 inversions utilizing measurements from a Siberian tower network (Japan-Russia Siberian Tall Tower Inland Observation Network; JR-STATION) and four aircraft sites, in addition to surface background flask measurements by the National Oceanic and Atmospheric Administration (NOAA). The inverse model estimates monthly fluxes for 68 regions globally. Our inversion with only the NOAA data yielded a boreal Eurasian CO2 flux of -0.56 ± 0.79 GtC yr-1, whereas we obtained a weaker uptake of -0.35 ± 0.61 GtC yr-1 when the Siberian data were also included. This difference is mainly explained by a weakened summer uptake, especially in East Siberia. We also found the inclusion of the Siberian data had significant impacts on inversion results over northeastern Europe as well as boreal Eurasia. The inversion with the Siberian data reduced the regional uncertainty by 22 % on average in boreal Eurasia, and further uncertainty reductions up to 80 % were found in eastern and western Siberia. Larger interannual variability was clearly seen in the inversion including the Siberia data than the inversion without the Siberia data. In the inversion with NOAA plus Siberia data, East Siberia showed larger interannual variability than that in West and Central Siberia. Finally, we conducted forward simulations using estimated fluxes and confirmed that the fit to independent measurements over Central Siberia, which were not included in the inversions, was visibly improved.

  2. Carbon flux estimation for Siberia by inverse modeling constrained by aircraft and tower CO2 measurements

    NASA Astrophysics Data System (ADS)

    Saeki, T.; Maksyutov, S.; Sasakawa, M.; Machida, T.; Arshinov, M.; Tans, P.; Conway, T. J.; Saito, M.; Valsala, V.; Oda, T.; Andres, R. J.; Belikov, D.

    2013-01-01

    Being one of the largest carbon reservoirs in the world, the Siberian carbon sink however remains poorly understood due to the limited numbers of observation. We present the first results of atmospheric CO2 inversions utilizing measurements from a Siberian tower network (Japan-Russia Siberian Tall Tower Inland Observation Network; JR-STATION) and four aircraft sites, in addition to surface background flask measurements by the National Oceanic and Atmospheric Administration (NOAA). Our inversion with only the NOAA data yielded a boreal Eurasian CO2 flux of -0.56 ± 0.79 GtC yr-1, whereas we obtained a weaker uptake of -0.35 ± 0.61 GtC yr-1 when the Siberian data were also included. This difference is mainly explained by a weakened summer uptake, especially in East Siberia. We also found the inclusion of the Siberian data had significant impacts on inversion results over northeastern Europe as well as boreal Eurasia. The inversion with the Siberian data reduced the regional uncertainty by 22% on average in boreal Eurasia, and further uncertainty reductions up to 80% were found in eastern and western Siberia. Larger interannual variability was clearly seen in the inversion which includes the Siberia data than the inversion without the Siberia data. In the inversion with NOAA plus Siberia data, east Siberia showed a larger interannual variability than that in west and central Siberia. Finally, we conducted forward simulations using estimated fluxes and confirmed that the fit to independent measurements over central Siberia, which were not included in inversions, was greatly improved.

  3. Evaluating and Constraining Ice Cloud Parameterizations in CAM5 using Aircraft Measurements from the SPARTICUS Campaign

    SciTech Connect

    Zhang, Kai; Liu, Xiaohong; Wang, Minghuai; Comstock, Jennifer M.; Mitchell, David; Mishra, Subhashree; Mace, Gerald G.

    2013-05-14

    This study uses aircraft measurements of relative humidity and ice crystal size distribution collected in synoptic cirrus during the SPARTICUS (Small PARTicles In CirrUS) field campaign to evaluate and constrain ice cloud parameterizations in the Community Atmosphere Model version 5. The probability density function (PDF) of ice crystal number concentration (Ni) derived from high frequency (1 Hz) measurements features a strong dependence on ambient temperature. As temperature decreases from -35°C to -62°C, the peak in the PDF shifts from 10-20 L-1 to 200-1000 L-1, while the ice crystal number concentration shows a factor of 6-7 increase. Model simulations are performed with two different insitu ice nucleation schemes. One of the schemes can reproduce a clear increase of Ni with decreasing temperature, by using either an observation based ice nuclei spectrum or a classical theory based spectrum with a relatively low (5%-10%) maximum freezing ratio for dust aerosols. The simulation with the other scheme, which assumes a high maximum freezing ratio (100%), shows much weaker temperature dependence of Ni. Simulations are also performed to test empirical parameters related to water vapor deposition and the auto-conversion of ice crystals to snow. Results show that a value between 0.05 and 0.1 for the water vapor deposition coefficient and 250 um for the critical ice crystal size can produce good agreements between model simulation and the SPARTICUS measurements in terms of ice crystal number concentration and effective radius. The climate impact of perturbing these parameters is also discussed.

  4. An overview of reactive chlorine measurements during the WINTER C-130 aircraft campaign

    NASA Astrophysics Data System (ADS)

    Thornton, J. A.; Lopez-Hilfiker, F.; Lee, B. H.; Jaegle, L.; Haskins, J.; Shah, V.; Brown, S. S.; Fibiger, D. L.; McDuffie, E. E.; Veres, P. R.; Dibb, J. E.; Sparks, T.; Ebben, C. J.; Cohen, R. C.; Sullivan, A.; Guo, H.; Weber, R. J.; Schroder, J. C.; Campuzano-Jost, P.; Day, D. A.; Jimenez, J. L.; Campos, T. L.; Weinheimer, A. J.; Apel, E. C.; Blake, N. J.

    2015-12-01

    As part of the Wintertime Investigation of Transport, Emissions, and Reactivity (WINTER) campaign, the University of Washington Iodide-adduct high resolution time of flight chemical ionization mass spectrometer (HRToF-CIMS) was deployed aboard the NSF/NCAR C-130 aircraft. Calibrated measurements of ClNO2, Cl2, HCl, N2O5, HNO3, HONO, among several other compounds, were made at 2Hz on all 13 research flights. ClNO2 and HCl were often the dominant forms of reactive gas-phase chlorine compounds, with ClNO2 routinely reaching >1.5 ppb in the polluted outflow of the eastern U.S. urban corridor. ClNO2 often becomes a substantial fraction (~30%) of NOz (NOz = NOy - NOx) in these plumes at night. Preliminary analyses suggests that ClNO2 production is most efficient in the polluted marine boundary layer, with yields approaching unity and the evolution of nighttime ClNO2 highly correlated with that of HNO3 and particulate nitrate. However, ClNO2 production was observed throughout the region and a significant source of reactive chlorine from coal-fired power plants was directly confirmed with measurements of HCl strongly correlated with SO2. In addition, there is some evidence that biomass or biofuel combustion is a source of reactive chlorine that can lead to ClNO2 production. Examples of the nocturnal and diel evolution of reactive chlorine species are given, and we show to our knowledge the first measurements of chlorine nitrate (ClONO2) in the polluted mid-latitude marine boundary layer.

  5. Short-range optical air data measurements for aircraft control using rotational Raman backscatter.

    PubMed

    Fraczek, Michael; Behrendt, Andreas; Schmitt, Nikolaus

    2013-07-15

    A first laboratory prototype of a novel concept for a short-range optical air data system for aircraft control and safety was built. The measurement methodology was introduced in [Appl. Opt. 51, 148 (2012)] and is based on techniques known from lidar detecting elastic and Raman backscatter from air. A wide range of flight-critical parameters, such as air temperature, molecular number density and pressure can be measured as well as data on atmospheric particles and humidity can be collected. In this paper, the experimental measurement performance achieved with the first laboratory prototype using 532 nm laser radiation of a pulse energy of 118 mJ is presented. Systematic measurement errors and statistical measurement uncertainties are quantified separately. The typical systematic temperature, density and pressure measurement errors obtained from the mean of 1000 averaged signal pulses are small amounting to < 0.22 K, < 0.36% and < 0.31%, respectively, for measurements at air pressures varying from 200 hPa to 950 hPa but constant air temperature of 298.95 K. The systematic measurement errors at air temperatures varying from 238 K to 308 K but constant air pressure of 946 hPa are even smaller and < 0.05 K, < 0.07% and < 0.06%, respectively. A focus is put on the system performance at different virtual flight altitudes as a function of the laser pulse energy. The virtual flight altitudes are precisely generated with a custom-made atmospheric simulation chamber system. In this context, minimum laser pulse energies and pulse numbers are experimentally determined, which are required using the measurement system, in order to meet measurement error demands for temperature and pressure specified in aviation standards. The aviation error margins limit the allowable temperature errors to 1.5 K for all measurement altitudes and the pressure errors to 0.1% for 0 m and 0.5% for 13000 m. With regard to 100-pulse-averaged temperature measurements, the pulse energy using 532 nm

  6. The effect of the duration of jet aircraft flyover sounds on judged annoyance. [noise predictions and noise measurements of jet aircrafts and human reactions to the noise intensity

    NASA Technical Reports Server (NTRS)

    Shepherd, K. P.

    1979-01-01

    The effect of the duration of jet aircraft flyover sounds on humans and the annoyance factor are examined. A nine point numerical category scaling technique is utilized for the study. Changes in the spectral characteristics of aircraft sounds caused by atmospheric attenuation are discussed. The effect of Doppler shifts using aircraft noises with minimal pure tone content is reported. The spectral content of sounds independent of duration and Doppler shift are examined by analysis of variance.

  7. Apparatus for Measuring Spectral Emissivity of Solid Materials at Elevated Temperatures

    NASA Astrophysics Data System (ADS)

    Ren, Dengfeng; Tan, Hong; Xuan, Yimin; Han, Yuge; Li, Qiang

    2016-05-01

    Spectral emissivity measurements at high temperature are of great importance for both scientific research and industrial applications. A method to perform spectral emissivity measurements is presented based on two sample heating methods, the flat plate and tubular furnace. An apparatus is developed to measure the normal spectral emissivity of solid material at elevated temperatures from 1073 K to 1873 K and wavelengths from 2 \\upmu hbox {m} to 25 \\upmu hbox {m}. Sample heating is accomplished by a torch flame or a high temperature furnace. Two different variable temperature blackbody sources are used as standard references and the radiance is measured by a FTIR spectrometer. Following calibration of the spectral response and background radiance of the spectrometer, the effect of the blackbody temperature interval on calibration results is discussed. Measurements are performed of the normal spectral emissivity of SiC and graphite over the prescribed temperature and wavelength range. The emissivity of SiC at high temperatures is compared with the emissivity at room temperature, and the influence of an oxide layer formed at the surface of SiC on the emissivity is studied. The effect of temperature on the emissivity of graphite is also investigated. Furthermore, a thorough analysis of the uncertainty components of the emissivity measurement is performed.

  8. A Remotely Piloted Aircraft (RPA) as a Measurement Tool for Wind-Energy Research

    NASA Astrophysics Data System (ADS)

    Wildmann, Norman; Bange, Jens

    2014-05-01

    In wind energy meteorology, RPA have the clear advantage compared to manned aircraft that they allow to fly very close to the ground and even in between individual wind turbines in a wind farm. Compared to meteorological towers and lidar systems, the advantage is the flexibility of the system, which makes it possible to measure at the desired site on short notice and not only in main wind direction. At the Center of Applied Geoscience at the University of Tübingen, the research RPA MASC (Multi-purpose Airborne Sensor Carrier) was developed. RPA of type MASC have a wingspan of about 3 m and a maximum take-off weight of 7.5 kg, including payload. The standard meteorological payload includes instruments for temperature, humidity, barometric pressure and wind measurement. It is possible to resolve turbulence fluctuations of wind and temperature up to 20 Hz. The autopilot ROCS (Research Onboard Computer System), which is developed at the Institute of Flight Mechanics and Control, University of Stuttgart, makes it possible to automatically follow predefined waypoints at constant altitude and airspeed. At a cruising speed of 24 m/s and a battery life of approx. one hour, a range of 80 km is feasible. The project 'Lidar Complex', funded by the German Federal Ministry for the Environment, Nature Conservation and Nuclear Safety, is part of the research network 'WindForS', based in Southern Germany. The goal of the project is to establish lidar technology for wind energy plant site evaluation in complex terrain. Additional goals are the comparison of different measurement techniques and the validation of wind-field models in not IEC 61400 conform terrain. It is planned to design a turbulent wind-field generator, fed by real measurement data, which can be used to analyse WEC behaviour. Two test sites were defined for the 'Lidar Complex' project, one in IEC-conform terrain about 15 km from the Baltic Sea, the other in the Swabian Alb, only 2 km downstream of a 100 m steep

  9. Aircraft measurements within a warm conveyor belt during the T-NAWDEX-FALCON campaign

    NASA Astrophysics Data System (ADS)

    Schäfler, Andreas; Boettcher, Maxi; Borrmann, Stephan; Busen, Reinhold; Dörnbrack, Andreas; Grams, Christian; Kaufmann, Stefan; Klingebiel, Marcus; Lammen, Yannick; Reutter, Philipp; Rautenhaus, Marc; Schlager, Hans; Sodemann, Harald; Voigt, Christiane; Wernli, Heini

    2013-04-01

    Warm Conveyor Belts (WCBs) are air streams that are highly relevant for the dynamics in the mid-latitudes as they strongly influence the evolution and intensity of northern hemispheric mid-latitude weather systems. For the predictability of cyclones the representation of diabatic processes associated with latent heat release due to phase transitions of water, surface fluxes, or radiative effects are believed to be a limiting factor. Diabatic processes in cyclones strongly depend on the transport of water vapor and are mainly organized and controlled by the coherently ascending WCB air masses. In October 2012 the T-NAWDEX-Falcon (THORPEX-North Atlantic Waveguide and Downstream Impact Experiment) campaign was organized by DLR Oberpfaffenhofen and ETH Zurich. During 9 research flights over Europe in-cloud measurements in WCBs were obtained with the DLR aircraft Falcon. Lagrangian flights were conducted with the aim to measure in the same air mass during different stages of the WCB to quantify the transport of moisture and the net latent heating along WCBs and their importance for forecast errors associated with mid-latitude weather systems. Besides in-situ observations of wind, temperature and humidity to characterize the thermodynamic structure of the WCBs, a set of dropsondes was deployed to gain a complete view on the complex structure of the cyclone. This presentation gives an overview of the three successful IOPs performed during the T-NAWDEX-Falcon campaign. To address forecast uncertainty and to enable flight planning up to four days in advance of the flights novel diagnostics based on deterministic and ensemble prediction NWP data were employed during the campaign. Furthermore a number of different trajectory models were applied for this field experiment. Based on selected flights from one intensive observation period the challenging planning process of Lagrangian matches of flight paths is described and first results are presented.

  10. Organophosphates in aircraft cabin and cockpit air--method development and measurements of contaminants.

    PubMed

    Solbu, Kasper; Daae, Hanne Line; Olsen, Raymond; Thorud, Syvert; Ellingsen, Dag Gunnar; Lindgren, Torsten; Bakke, Berit; Lundanes, Elsa; Molander, Paal

    2011-05-01

    Methods for measurements and the potential for occupational exposure to organophosphates (OPs) originating from turbine and hydraulic oils among flying personnel in the aviation industry are described. Different sampling methods were applied, including active within-day methods for OPs and VOCs, newly developed passive long-term sample methods (deposition of OPs to wipe surface areas and to activated charcoal cloths), and measurements of OPs in high-efficiency particulate air (HEPA) recirculation filters (n = 6). In total, 95 and 72 within-day OP and VOC samples, respectively, have been collected during 47 flights in six different models of turbine jet engine, propeller and helicopter aircrafts (n = 40). In general, the OP air levels from the within-day samples were low. The most relevant OP in this regard originating from turbine and engine oils, tricresyl phosphate (TCP), was detected in only 4% of the samples (min-max

  11. Physical Processes Governing Atmospheric Trace Constituents Measured from an Aircraft on PEM-Tropics

    NASA Technical Reports Server (NTRS)

    Newell, Reginald E.; Hoell, James M., Jr. (Technical Monitor)

    2001-01-01

    Before the mission, the PI (principal investigator) was instrumental in securing real-time use of the new 51-level ECMWF (European Centre for Medium Range Weather Forecasts) meteorological data. During the mission, he provided flight planning and execution guidance as meteorologist for the P-3B. Mr. Yong Zhu computed and plotted meteorological forecast maps using the ECMWF data and transmitted them to the field from MIT (Massachusetts Institute of Technology). Dr. John Cho was in the field for the Christmas Island portion to extract data from the on-site NOAA (National Oceanic and Atmospheric Administration) radars for local wind profiles that were used at the flight planning meetings. When the power supply for the VHF radar failed, he assisted the NOAA engineer in its repair. After the mission, Mr. Zhu produced meteorological data memos, which were made available to the PEM (Pacific Exploratory Mission)-Tropics B science team on request. An undergraduate student, Ms. Danielle Morse, wrote memos annotating the cloud conditions seen on the aircraft external monitor video tapes. Dr. Cho and the PI circulated a memo regarding the status (and associated problems) of the meteorological measurement systems on the DC-8 and P-3B to the relevant people on the science team. Several papers by members of our project were completed and accepted by JGR (Journal of Geophysical Research) for the first special section on PEM-Tropics B. These papers included coverage of the following topics: 1) examination of boundary layer data; 2) water vapor transport; 3) tropospheric trace constituent layers; 4) summarizations of the meteorological background and events during PEM-Tropics B; 5) concomitant lidar measurements of ozone, water vapor, and aerosol.

  12. A strategy for in-flight measurements of physiology of pilots of high-performance fighter aircraft.

    PubMed

    West, John B

    2013-07-01

    Some pilots flying modern high-performance fighter aircraft develop "hypoxia-like" incidents characterized by short periods of confusion and cognitive impairment. The problem is serious and recently led to the grounding of a fleet of aircraft. Extensive discussions of the incidents have taken place but some people believe that there is inadequate data to determine the cause. There is a tremendous disconnect between what is known about the function of the aircraft and the function of the pilot. This paper describes a plan for measuring the inspired and expired Po2 and Pco2 in the pilot's mask, the inspiratory flow rate, and pressure in the mask. A critically important requirement is that the interference with the function of the pilot is minimal. Although extensive physiological measurements were previously made on pilots in ground-based experiments such as rapid decompression in an altitude chamber and increased acceleration on a centrifuge, in-flight measurements of gas exchange have not been possible until now primarily because of the lack of suitable equipment. The present paper shows how the recent availability of small, rapidly responding oxygen and carbon dioxide analyzers make sophisticated in-flight measurements feasible. The added information has the potential of greatly improving our knowledge of pilot physiology, which could lead to an explanation for the incidents.

  13. A study of methods of prediction and measurement of the transmission sound through the walls of light aircraft

    NASA Technical Reports Server (NTRS)

    Forssen, B.; Wang, Y. S.; Crocker, M. J.

    1981-01-01

    Several aspects were studied. The SEA theory was used to develop a theoretical model to predict the transmission loss through an aircraft window. This work mainly consisted of the writing of two computer programs. One program predicts the sound transmission through a plexiglass window (the case of a single partition). The other program applies to the case of a plexiglass window window with a window shade added (the case of a double partition with an air gap). The sound transmission through a structure was measured in experimental studies using several different methods in order that the accuracy and complexity of all the methods could be compared. Also, the measurements were conducted on the simple model of a fuselage (a cylindrical shell), on a real aircraft fuselage, and on stiffened panels.

  14. The NASA Airborne Tropical TRopopause EXperiment (ATTREX):High-Altitude Aircraft Measurements in the Tropical Western Pacific

    NASA Technical Reports Server (NTRS)

    Jensen, E. J.; Pfister, L.; Jordan, D. E.; Bui, T. V.; Ueyama, R.; Singh, H. B.; Lawson, P.; Thornberry, T.; Diskin, G.; McGill, M.; Pittman, J.; Atlas, E.; Kim, J.

    2016-01-01

    The February through March 2014 deployment of the NASA Airborne Tropical TRopopause EXperiment (ATTREX) provided unique in situ measurements in the western Pacific Tropical Tropopause Layer (TTL). Six flights were conducted from Guam with the long-range, high-altitude, unmanned Global Hawk aircraft. The ATTREX Global Hawk payload provided measurements of water vapor, meteorological conditions, cloud properties, tracer and chemical radical concentrations, and radiative fluxes. The campaign was partially coincident with the CONTRAST and CAST airborne campaigns based in Guam using lower-altitude aircraft The ATTREX dataset is being used for investigations of TTL cloud, transport, dynamical, and chemical processes as well as for evaluation and improvement of global-model representations of TTL processes.

  15. Predictions of F-111 TACT aircraft buffet response and correlations of fluctuating pressures measured on aluminum and steel models and the aircraft

    NASA Technical Reports Server (NTRS)

    Coe, Charles F.; Cunningham, Atlee M., Jr.

    1987-01-01

    Results of buffet research that was conducted as part of the joint USAF/NASA F-111 TACT Research Program are presented. The correlation of wind tunnel and flight measurements of buffet excitation showed that there generally was good agreement between measurements of pressure fluctuations on the models and aircraft in regions of separated flow. At shock-wave boundaries of the separated flow, correlations of pressure fluctuations were not so good, due to Reynolds number and static elastic effects. The buffet prediction method, which applies a forcing function that is obtained by real-time integration of pressure time histories with the natural modes, is described. The generalized forces, including the effects of wing and tail, correlations of predicted and measured damping, and correlations of predicted and measured buffet response are presented. All presented data are for a Mach number of 0.8 with wing-sweep angles of 26 and 35 deg for a range of angles-of-attack that include buffet onset to high intensity buffeting. Generally, the buffet predictions were considered to be quite good particularly in light of past buffet-prediction experience.

  16. Field measurements confirm that hillslope sediment size varies with elevation and geomorphic process regime at Inyo Creek, California

    NASA Astrophysics Data System (ADS)

    Genetti, J. R.; Sklar, L. S.; Leclere, S.

    2015-12-01

    Correlating the spatial variation of hillslope sediment grain size with geomorphic process regimes is essential for understanding feedbacks between sediment production on hillslopes and channel processes. At our field site at Inyo Creek, California, an elevation gradient in the size of sediment produced on hillslopes has been quantified using cosmogenic nuclides and detrital thermochronometry with samples collected at the outlet. Here we report field measurements of surface sediment size from hillslopes within the catchment, which validate those findings. Specifically, we use multiple field methods to measure hillslope grain size distributions, and correlate size variations with geomorphic process regimes across an elevation gradient. We select sampling sites from maps of predicted grain size created by overlaying landscape attributes in GIS to delineate geomorphic landscape units (GLUs). Geomorphic process regimes include bare bedrock, angle of repose slopes of talus, landslide deposits and soil mantled convex hillslopes. We use tape transects and point counts to quantify size distributions of regolith covered slopes. We also analyze photographs using The Digital Grain Size Project software, and for sediments too small to be resolved in photos we collect bulk samples for sieve analysis in the lab. To measure joint spacing, and infer the initial size distribution of rock fragments produced by bare bedrock, we use combine photographs with measurements made with tape transects, and aerial photographs for inaccessible areas. Our findings indicate that higher elevation slopes do indeed supply coarser sediment. Lower elevations have bimodal size distributions composed of sand with scattered boulders, while at higher elevations, slopes are composed a unimodal distribution of gravel, cobbles, and boulders. While boulder density does not vary significantly with elevation, we find a highly significant linear increase in the fraction of gravel and cobble-sized particles with

  17. Soot surface temperature measurements in pure and diluted flames at atmospheric and elevated pressures

    SciTech Connect

    Berry Yelverton, T.L.; Roberts, W.L.

    2008-10-15

    Soot surface temperature was measured in laminar jet diffusion flames at atmospheric and elevated pressures. The soot surface temperature was measured in flames at one, two, four, and eight atmospheres with both pure and diluted (using helium, argon, nitrogen, or carbon dioxide individually) ethylene fuels with a calibrated two-color soot pyrometry technique. These two dimensional temperature profiles of the soot aid in the analysis and understanding of soot production, leading to possible methods for reducing soot emission. Each flame investigated was at its smoke point, i.e., at the fuel flow rate where the overall soot production and oxidation rates are equal. The smoke point was chosen because it was desirable to have similar soot loadings for each flame. A second set of measurements were also taken where the fuel flow rate was held constant to compare with earlier work. These measurements show that overall flame temperature decreases with increasing pressure, with increasing pressure the position of peak temperature shifts to the tip of the flame, and the temperatures measured were approximately 10% lower than those calculated assuming equilibrium and neglecting radiation. (author)

  18. Online measurements of the emissions of intermediate-volatility and semi-volatile organic compounds from aircraft

    NASA Astrophysics Data System (ADS)

    Cross, E. S.; Hunter, J. F.; Carrasquillo, A. J.; Franklin, J. P.; Herndon, S. C.; Jayne, J. T.; Worsnop, D. R.; Miake-Lye, R. C.; Kroll, J. H.

    2013-03-01

    A detailed understanding of the climate and air quality impacts of aviation requires detailed measurements of the emissions of intermediate-volatility and semi-volatile organic compounds (I/SVOCs) from aircraft. Currently both the amount and chemical composition of aircraft I/SVOC emissions remain poorly characterized. Here we characterize I/SVOC emissions from aircraft, using a novel instrument for the online, quantitative measurement of the mass loading and composition of low-volatility organic vapors. Emissions from the NASA DC8 aircraft were sampled on the ground, 143 m downwind of the engines and characterized as a function of engine power from ground idle (~4% maximum rated thrust) through 85% power. Results show that I/SVOC emissions are highest during engine-idle operating conditions, with decreasing but non-zero I/SVOC emissions at higher engine powers. Comparison of I/SVOC emissions with total hydrocarbon (THC) measurements, VOC measurements, and an established emissions profile indicates that I/SVOCs comprise 10-20% of the total organic gas phase emissions at idle, and an increasing fraction of the total gas phase organic emissions at higher powers. Positive matrix factorization of online mass spectra is used to identify three distinct types of I/SVOC emissions: aliphatic, aromatic and oxygenated. The volatility and chemical composition of the emissions suggest that unburned fuel is the dominant source of I/SVOCs at idle, while pyrolysis products make up an increasing fraction of the I/SVOCs at higher powers. Oxygenated I/SVOC emissions were detected at lower engine powers (≤30%) and may be linked to cracked, partially oxidized or unburned fuel components.

  19. Online measurements of the emissions of intermediate-volatility and semi-volatile organic compounds from aircraft

    NASA Astrophysics Data System (ADS)

    Cross, E. S.; Hunter, J. F.; Carrasquillo, A. J.; Franklin, J. P.; Herndon, S. C.; Jayne, J. T.; Worsnop, D. R.; Miake-Lye, R. C.; Kroll, J. H.

    2013-08-01

    A detailed understanding of the climate and air quality impacts of aviation requires measurements of the emissions of intermediate-volatility and semi-volatile organic compounds (I/SVOCs) from aircraft. Currently both the amount and chemical composition of aircraft I/SVOC emissions remain poorly characterized. Here we characterize I/SVOC emissions from aircraft, using a novel instrument for the online, quantitative measurement of the mass loading and composition of low-volatility organic vapors. Emissions from the NASA DC8 aircraft were sampled on the ground 143 m downwind of the engines and characterized as a function of engine power from idle (4% maximum rated thrust) through 85% power. Results show that I/SVOC emissions are highest during engine idle operating conditions, with decreasing but non-zero I/SVOC emissions at higher engine powers. Comparison of I/SVOC emissions with total hydrocarbon (THC) measurements, VOC measurements, and an established emissions profile indicates that I/SVOCs comprise 10-20% of the total organic gas-phase emissions at idle, and an increasing fraction of the total gas-phase organic emissions at higher powers. Positive matrix factorization of online mass spectra is used to identify three distinct types of I/SVOC emissions: aliphatic, aromatic and oxygenated. The volatility and chemical composition of the emissions suggest that unburned fuel is the dominant source of I/SVOCs at idle, while pyrolysis products make up an increasing fraction of the I/SVOCs at higher powers. Oxygenated I/SVOC emissions were detected at lower engine powers (≤30%) and may be linked to cracked, partially oxidized or unburned fuel components.

  20. Measurement of dose equivalent distribution on-board commercial jet aircraft.

    PubMed

    Kubančák, J; Ambrožová, I; Ploc, O; Pachnerová Brabcová, K; Štěpán, V; Uchihori, Y

    2014-12-01

    The annual effective doses of aircrew members often exceed the limit of 1 mSv for the public due to the increased level of cosmic radiation at the flight altitudes, and thus, it is recommended to monitor them [International Commission on Radiation Protection. 1990 Recommendations of the International Commission on Radiological Protection. ICRP Publication 60. Ann. ICRP 21: (1-3), (1991)]. According to the Monte Carlo simulations [Battistoni, G., Ferrari, A., Pelliccioni, M. and Villari, R. Evaluation of the doses to aircrew members taking into consideration the aircraft structures. Adv. Space Res. 36: , 1645-1652 (2005) and Ferrari, A., Pelliccioni, M. and Villari, R. Evaluation of the influence of aircraft shielding on the aircrew exposure through an aircraft mathematical model. Radiat. Prot. Dosim. 108: (2), 91-105 (2004)], the ambient dose equivalent rate Ḣ*(10) depends on the location in the aircraft. The aim of this article is to experimentally evaluate Ḣ*(10) on-board selected types of aircraft. The authors found that Ḣ*(10) values are higher in the front and the back of the cabin and lesser in the middle of the cabin. Moreover, total dosimetry characteristics obtained in this way are in a reasonable agreement with other data, in particular with the above-mentioned simulations.

  1. Aircraft health and usage monitoring system for in-flight strain measurement of a wing structure

    NASA Astrophysics Data System (ADS)

    Kim, Jin-Hyuk; Park, Yurim; Kim, Yoon-Young; Shrestha, Pratik; Kim, Chun-Gon

    2015-10-01

    This paper presents an aircraft health and usage monitoring system (HUMS) using fiber Bragg grating (FBG) sensors. This study aims to implement and evaluate the HUMS for in-flight strain monitoring of aircraft structures. An optical-fiber-based HUMS was developed and applied to an ultralight aircraft that has a rectangular wing shape with a strut-braced configuration. FBG sensor arrays were embedded into the wing structure during the manufacturing process for effective sensor implementation. Ground and flight tests were conducted to verify the integrity and availability of the installed FBG sensors and HUMS devices. A total of 74 flight tests were conducted using the HUMS implemented testbed aircraft, considering various maneuvers and abnormal conditions. The flight test results revealed that the FBG-based HUMS was successfully implemented on the testbed aircraft and operated normally under the actual flight test environments as well as providing reliable in-flight strain data from the FBG sensors over a long period of time.

  2. Biomechanical evaluation of heel elevation on load transfer — experimental measurement and finite element analysis

    NASA Astrophysics Data System (ADS)

    Luximon, Yan; Luximon, Ameersing; Yu, Jia; Zhang, Ming

    2012-02-01

    In spite of ill-effects of high heel shoes, they are widely used for women. Hence, it is essential to understand the load transfer biomechanics in order to design better fit and comfortable shoes. In this study, both experimental measurement and finite element analysis were used to evaluate the biomechanical effects of heel height on foot load transfer. A controlled experiment was conducted using custom-designed platforms. Under different weight-bearing conditions, peak plantar pressure, contact area and center of pressure were analyzed. A three-dimensional finite element foot model was used to simulate the high-heel support and to predict the internal stress distributions and deformations for different heel heights. Results from both experiment and model indicated that heel elevations had significant effects on all variables. When heel elevation increased, the center of pressure shifted from the midfoot region to the forefoot region, the contact area was reduced by 26% from 0 to 10.2 cm heel and the internal stress of foot bones increased. Prediction results also showed that the strain and total tension force of plantar fascia was minimum at 5.1 cm heel condition. This study helps to better understand the biomechanical behavior of foot, and to provide better suggestions for design parameters of high heeled shoes.

  3. Elevated objectively measured but not self-reported energy intake predicts future weight gain in adolescents

    PubMed Central

    Stice, Eric; Durant, Shelley

    2014-01-01

    Background Although obesity putatively occurs when individuals consume more calories than needed for metabolic needs, numerous risk factor studies have not observed significant positive relations between reported caloric intake and future weight gain, potentially because reported caloric intake is inaccurate. Objective The present study tested the hypothesis that objectively measured habitual energy intake, estimated with doubly labeled water, would show a stronger positive relation to future weight gain than self-reported caloric intake based on a widely used food frequency measure. Design 253 adolescents completed a doubly labeled water (DLW) assessment of energy intake (EI), a food frequency measure, and a resting metabolic rate (RMR) assessment at baseline, and had their body mass index (BMI) measured at baseline and at 1- and 2-year follow-ups. Results Controlling for baseline RMR, elevated objectively measured EI, but not self-reported habitual caloric intake, predicted increases in BMI over a 2-year follow-up. On average, participants under-reported caloric intake by 35%. Conclusions Results provide support for the thesis that self-reported caloric intake has not predicted future weight gain because it is less accurate than objectively measured habitual caloric intake, suggesting that food frequency measures can lead to misleading findings. However, even objectively measured caloric intake showed only a moderate relation to future weight gain, implying that habitual caloric intake fluctuates over time and that it may be necessary to conduct serial assessments of habitual intake to better reflect the time-varying effects of caloric intake on weight gain. PMID:24930597

  4. Use of Collocated KWAJEX Satellite, Aircraft, and Ground Measurements for Understanding Ambiguities in TRMM Radiometer Rain Profile Algorithm

    NASA Technical Reports Server (NTRS)

    Smith, Eric A.; Fiorino, Steven

    2002-01-01

    Coordinated ground, aircraft, and satellite observations are analyzed from the 1999 TRMM Kwajalein Atoll field experiment (KWAJEX) to better understand the relationships between cloud microphysical processes and microwave radiation intensities in the context of physical evaluation of the Level 2 TRMM radiometer rain profile algorithm and uncertainties with its assumed microphysics-radiation relationships. This talk focuses on the results of a multi-dataset analysis based on measurements from KWAJEX surface, air, and satellite platforms to test the hypothesis that uncertainties in the passive microwave radiometer algorithm (TMI 2a12 in the nomenclature of TRMM) are systematically coupled and correlated with the magnitudes of deviation of the assumed 3-dimensional microphysical properties from observed microphysical properties. Re-stated, this study focuses on identifying the weaknesses in the operational TRMM 2a12 radiometer algorithm based on observed microphysics and radiation data in terms of over-simplifications used in its theoretical microphysical underpinnings. The analysis makes use of a common transform coordinate system derived from the measuring capabilities of the aircraft radiometer used to survey the experimental study area, i.e., the 4-channel AMPR radiometer flown on the NASA DC-8 aircraft. Normalized emission and scattering indices derived from radiometer brightness temperatures at the four measuring frequencies enable a 2-dimensional coordinate system that facilities compositing of Kwajalein S-band ground radar reflectivities, ARMAR Ku-band aircraft radar reflectivities, TMI spacecraft radiometer brightness temperatures, PR Ku-band spacecraft radar reflectivities, bulk microphysical parameters derived from the aircraft-mounted cloud microphysics laser probes (including liquid/ice water contents, effective liquid/ice hydrometeor radii, and effective liquid/ice hydrometeor variances), and rainrates derived from any of the individual ground, aircraft

  5. Apparatus and Method for Measuring Air Temperature Ahead of an Aircraft for Controlling a Variable Inlet/Engine Assembly

    NASA Technical Reports Server (NTRS)

    Gary, Bruce L. (Inventor)

    2001-01-01

    The apparatus and method employ remote sensing to measure the air temperature a sufficient distance ahead of the aircraft to allow time for a variable inlet/engine assembly to be reconfigured in response to the measured temperature, to avoid inlet unstart and/or engine compressor stall. In one embodiment, the apparatus of the invention has a remote sensor for measuring at least one air temperature ahead of the vehicle and an inlet control system for varying the inlet. The remote sensor determines a change in temperature value using at least one temperature measurement and prior temperature measurements corresponding to the location of the aircraft. The control system uses the change in air temperature value to vary the inlet configuration to maintain the position of the shock wave during the arrival of the measured air in the inlet. In one embodiment, the method of the invention includes measuring at least one air temperature ahead of the vehicle, determining an air temperature at the vehicle from prior air temperature measurements, determining a change in temperature value using the air temperature at the vehicle and the at least one air temperature measurement ahead of the vehicle, and using the change in temperature value to-reposition the airflow inlet, to cause the shock wave to maintain substantially the same position within the inlet as the airflow temperature changes within the inlet.

  6. An automated flow calorimeter for heat capacity and enthalpy measurements at elevated temperatures and pressures

    SciTech Connect

    Yesavage, V.F.

    1990-08-31

    The need for highly accurate thermal property data for a broad range of new application fluids is well documented. To facilitate expansion of the current thermophysical database, an automated flow calorimeter was developed for the measurement of highly accurate isobaric heat capacities and enthalpies of fluids at elevated temperatures and pressures. The experimental technique utilizes traditional electrical power input, adiabatic flow calorimetry with a precision metering pump that eliminates the need for on-line flow rate monitoring. In addition, a complete automation system, greatly simplifies the operation of the apparatus and increases the rapidity of the measurement process. The range over which the instrument was tested, was 300--600 K and 0--12 Mpa, although the calorimeter should perform up to the original design goals of 700 K and 30 MPa. The new flow calorimeter was evaluated by measuring the mean, isobaric, specific heat capacities of liquid water and n-pentane. These experiments yielded an average deviation from the standard literature data of +0.02% and a total variation of 0.05%. Additional data analysis indicated that the overall measurement uncertainty was conservatively estimated as 0.2% with an anticipated precision of 0.1--0.15% at all operating conditions. 44 refs., 27 figs., 2 tabs.

  7. Analysis and correction of ground reflection effects in measured narrowband sound spectra using cepstral techniques. [aircraft noise analysis

    NASA Technical Reports Server (NTRS)

    Miles, J. H.; Stevens, G. H.; Leininger, G. G.

    1975-01-01

    Ground reflections generate undesirable effects on acoustic measurements such as those conducted outdoors for jet noise research, aircraft certification, and motor vehicle regulation. This paper shows how cepstral techniques developed in speech processing can be adapted to identify the echo delay time and to correct for ground reflection effects. A sample result is presented using an actual narrowband sound pressure level spectrum. The technique can readily be adapted to existing fast Fourier transform type spectrum measurement instrumentation to provide field measurement of echo time delays.

  8. Infrared lidar windshear detection for commercial aircraft and the edge technique, a new method for atmospheric wind measurement

    NASA Technical Reports Server (NTRS)

    Targ, Russell; Bowles, Roland L.; Korb, C. L.; Gentry, Bruce M.; Souilhac, Dominique

    1991-01-01

    The edge technique, a new method for measuring small frequency shifts, is described. The technique allows high-accuracy measurement of atmospheric winds (0.2-1 m/s) with a high vertical resolution (10 m) using currently available technology. With the edge technique, a lidar system can be used to obtain range resolved measurements of the wind in the atmosphere from the ground, aircraft, or spaceborne platforms. The edge technique can be used with different lasers over a broad range of wavelengths.

  9. A study of extractive and remote-sensing sampling and measurement of emissions from military aircraft engines

    NASA Astrophysics Data System (ADS)

    Cheng, Meng-Dawn; Corporan, Edwin

    2010-12-01

    Aircraft emissions contribute to the increased atmospheric burden of particulate matter (PM) that plays an important role in air quality, human health, visibility, contrail formation and climate change. Sampling and measurement of modern aircraft emissions at the engine exhaust plane (EEP) for engine and fuel certification remains challenging, as no agency-certified method is available. In this paper we summarize the results of three recent field studies devoted to investigate the consistency and applicability of "extractive" and "optical remote-sensing" (ORS) technologies in the sampling and measurement of gaseous and PM emitted by a number of military aircraft engines. Three classes of military engines were investigated; these include T56, TF33, and T700 & T701C types of engines, which consume 70-80% of the military aviation fuel each year. JP-8 and Fischer-Tropsch (FT)-derived paraffinic fuels were used to study the effect of fuels. It was found that non-volatile particles in the engine emissions were in the 20 nm range for the low power condition of new helicopter engines to 80 nm for the high power condition of legacy engines. Elemental analysis indicated little metals were present on particles, while most of the materials on the exhaust particles were carbon and sulfate based. Alkanes, carbon monoxide, carbon dioxide, nitrogen oxides, sulfur dioxide, formaldehyde, ethylene, acetylene and propylene were detected. The last five species were most noticeable only under low engine power. The emission indices calculated based on the ORS data deviate significantly from those based on the extractive data. Nevertheless, the ORS techniques were useful in the sense that it provided non-intrusive real-time detection of species in the exhaust plume, which warrants further development. The results obtained in this program help validate sampling methodology and measurement techniques used for non-volatile PM aircraft emissions as described in the SAE AIR6037 (2009).

  10. Unmanned aircraft system measurements of the atmospheric boundary layer over Terra Nova Bay, Antarctica

    NASA Astrophysics Data System (ADS)

    Knuth, S. L.; Cassano, J. J.; Maslanik, J. A.; Herrmann, P. D.; Kernebone, P. A.; Crocker, R. I.; Logan, N. J.

    2012-11-01

    In September 2009, a series of long-range unmanned aircraft system (UAS) flights collected basic atmospheric data over the Terra Nova Bay polynya in Antarctica. Air temperature, wind, pressure, relative humidity, radiation, skin temperature, GPS, and operational aircraft data were collected and quality controlled for scientific use. The data has been submitted to the United States Antarctic Program Data Coordination Center (USAP-DCC) for free access (doi:10.1594/USAP/0739464).

  11. Unmanned aircraft system measurements of the atmospheric boundary layer over Terra Nova Bay, Antarctica

    NASA Astrophysics Data System (ADS)

    Knuth, S. L.; Cassano, J. J.; Maslanik, J. A.; Herrmann, P. D.; Kernebone, P. A.; Crocker, R. I.; Logan, N. J.

    2013-02-01

    In September 2009, a series of long-range unmanned aircraft system (UAS) flights collected basic atmospheric data over the Terra Nova Bay polynya in Antarctica. Air temperature, wind, pressure, relative humidity, radiation, skin temperature, GPS, and operational aircraft data were collected and quality controlled for scientific use. The data have been submitted to the United States Antarctic Program Data Coordination Center (USAP-DCC) for free access (doi:10.1594/USAP/0739464).

  12. Tracking and Characterization of Aircraft Wakes Using Acoustic and Lidar Measurements

    NASA Technical Reports Server (NTRS)

    Booth, Earl R., Jr.; Humphreys, William M., Jr.

    2005-01-01

    Data from the 2003 Denver International Airport Wake Acoustics Test are further examined to discern spectral content of aircraft wake signatures, and to compare three dimensional wake tracking from acoustic data to wake tracking data obtained through use of continuous wave and pulsed lidar. Wake tracking data derived from acoustic array data agree well with both continuous wave and pulsed lidar in the horizontal plane, but less well with pulsed lidar in the vertical direction. Results from this study show that the spectral distribution of acoustic energy in a wake signature varies greatly with aircraft type.

  13. NASA's Operation Icebridge: Using Instrumented Aircraft to Bridge the Observational Gap Between Icesat and Icesat-2 Laser Altimeter Measurements

    NASA Astrophysics Data System (ADS)

    Studinger, M.

    2014-12-01

    NASA's Operation IceBridge images Earth's polar ice in unprecedented detail to better understand processes that connect the polar regions with the global climate system. Operation IceBridge utilizes a highly specialized fleet of research aircraft and the most sophisticated suite of innovative science instruments ever assembled to characterize annual changes in thickness of sea ice, glaciers, and ice sheets. In addition, Operation IceBridge collects critical data used to predict the response of Earth's polar ice to climate change and resulting sea-level rise. IceBridge also helps bridge the gap in polar observations between NASA's ICESat satellite missions. Combined with previous aircraft observations, as well as ICESat, CryoSat-2 and the forthcoming ICESat-2 observations, Operation IceBridge will produce a cross-calibrated 17-year time series of ice sheet and sea-ice elevation data over Antarctica, as well as a 27-year time series over Greenland. These time series will be a critical resource for predictive models of sea ice and ice sheet behavior. In addition to laser altimetry, Operation IceBridge is using a comprehensive suite of instruments to produce a three-dimensional view of the Arctic and Antarctic ice sheets, ice shelves and the sea ice. The suite includes two NASA laser altimeters, the Airborne Topographic Mapper (ATM) and the Land, Vegetation and Ice Sensor (LVIS); four radar systems from the University of Kansas' Center for Remote Sensing of Ice Sheets (CReSIS), a Ku-band radar altimeter, accumulation radar, snow radar and the Multichannel Coherent Radar Depth Sounder (MCoRDS); a Sander Geophysics airborne gravimeter (AIRGrav), a magnetometer and a high-resolution stereographic camera (DMS). Since its start in 2009, Operation IceBridge has deployed 8 geophysical survey aircraft and 19 science instruments. All IceBridge data is freely available from NSIDC (http://nsidc.org/data/icebridge) 6 months after completion of a campaign.

  14. Temperature elevation by HIFU in ex vivo porcine muscle: MRI measurement and simulation study

    SciTech Connect

    Solovchuk, Maxim A.; Hwang, San Chao; Chang, Hsu; Thiriet, Marc; Sheu, Tony W. H.

    2014-05-15

    Purpose: High-intensity focused ultrasound is a rapidly developing medical technology with a large number of potential clinical applications. Computational model can play a pivotal role in the planning and optimization of the treatment based on the patient's image. Nonlinear propagation effects can significantly affect the temperature elevation and should be taken into account. In order to investigate the importance of nonlinear propagation effects, nonlinear Westervelt equation was solved. Weak nonlinear propagation effects were studied. The purpose of this study was to investigate the correlation between the predicted and measured temperature elevations and lesion in a porcine muscle. Methods: The investigated single-element transducer has a focal length of 12 cm, an aperture of 8 cm, and frequency of 1.08 MHz. Porcine muscle was heated for 30 s by focused ultrasound transducer with an acoustic power in the range of 24–56 W. The theoretical model consists of nonlinear Westervelt equation with relaxation effects being taken into account and Pennes bioheat equation. Results: Excellent agreement between the measured and simulated temperature rises was found. For peak temperatures above 85–90 °C “preboiling” or cavitation activity appears and lesion distortion starts, causing small discrepancy between the measured and simulated temperature rises. From the measurements and simulations, it was shown that distortion of the lesion was caused by the “preboiling” activity. Conclusions: The present study demonstrated that for peak temperatures below 85–90 °C numerical simulation results are in excellent agreement with the experimental data in three dimensions. Both temperature rise and lesion size can be well predicted. Due to nonlinear effect the temperature in the focal region can be increased compared with the linear case. The current magnetic resonance imaging (MRI) resolution is not sufficient. Due to the inevitable averaging the measured

  15. Rapid, optical measurement of the atmospheric pressure on a fast research aircraft using open-path TDLAS

    NASA Astrophysics Data System (ADS)

    Buchholz, B.; Afchine, A.; Ebert, V.

    2014-05-01

    Because of the high travel speed, the complex flow dynamics around an aircraft and the complex dependency of the fluid dynamics on numerous airborne parameters, it is quite difficult to obtain accurate pressure values at a specific instrument location of an aircraft's fuselage. Complex simulations using computational fluid dynamics (CFD) models can in theory computationally "transfer" pressure values from one location to another. However, for long flight patterns, this process is inconvenient and cumbersome. Furthermore these CFD transfer models require a local experimental validation, which is rarely available. In this paper, we describe an integrated approach for a spectroscopic, calibration-free, in-flight pressure determination in an open-path White cell on an aircraft fuselage using ambient, atmospheric water vapour as the "sensor species". The presented measurements are realized with the HAI (Hygrometer for Atmospheric Investigations) instrument, built for multiphase water detection via calibration-free TDLAS (tunable diode laser absorption spectroscopy). The pressure determination is based on raw data used for H2O concentration measurement, but with a different post-flight evaluation method, and can therefore be conducted at deferred time intervals on any desired flight track. The spectroscopic pressure is compared in-flight with the static ambient pressure of the aircraft avionic system and a micro-mechanical pressure sensor, located next to the open-path cell, over a pressure range from 150 hPa to 800 hPa, and a water vapour concentration range of more than three orders of magnitude. The correlation between the micro-mechanical pressure sensor measurements and the spectroscopic pressure measurements show an average deviation from linearity of only 0.14% and a small offset of 9.5 hPa. For the spectroscopic pressure evaluation we derive measurement uncertainties under laboratory conditions of 3.2% and 5.1% during in flight operation on the HALO airplane

  16. Rapid, optical measurement of the atmospheric pressure on a fast research aircraft using open-path TDLAS

    NASA Astrophysics Data System (ADS)

    Buchholz, B.; Afchine, A.; Ebert, V.

    2014-11-01

    Because of the high travel speed, the complex flow dynamics around an aircraft, and the complex dependency of the fluid dynamics on numerous airborne parameters, it is quite difficult to obtain accurate pressure values at a specific instrument location of an aircraft's fuselage. Complex simulations using computational fluid dynamics (CFD) models can in theory computationally "transfer" pressure values from one location to another. However, for long flight patterns, this process is inconvenient and cumbersome. Furthermore, these CFD transfer models require a local experimental validation, which is rarely available. In this paper, we describe an integrated approach for a spectroscopic, calibration-free, in-flight pressure determination in an open-path White cell on an aircraft fuselage using ambient, atmospheric water vapour as the "sensor species". The presented measurements are realised with the HAI (Hygrometer for Atmospheric Investigations) instrument, built for multiphase water detection via calibration-free TDLAS (tunable diode laser absorption spectroscopy). The pressure determination is based on raw data used for H2O concentration measurement, but with a different post-flight evaluation method, and can therefore be conducted at deferred time intervals on any desired flight track. The spectroscopic pressure is compared in-flight with the static ambient pressure of the aircraft avionic system and a micro-mechanical pressure sensor, located next to the open-path cell, over a pressure range from 150 to 800 hPa, and a water vapour concentration range of more than 3 orders of magnitude. The correlation between the micro-mechanical pressure sensor measurements and the spectroscopic pressure measurements shows an average deviation from linearity of only 0.14% and a small offset of 9.5 hPa. For the spectroscopic pressure evaluation we derive measurement uncertainties under laboratory conditions of 3.2 and 5.1% during in-flight operation on the HALO airplane. Under

  17. Measurements of total odd nitrogen (NOy) aboard MOZAIC in-service aircraft: instrument design, operation and performance

    NASA Astrophysics Data System (ADS)

    Volz-Thomas, A.; Berg, M.; Heil, T.; Houben, N.; Lerner, A.; Petrick, W.; Raak, D.; Pätz, H.-W.

    2005-02-01

    A small system for the unattended measurement of total odd nitrogen (NOy, i.e., the sum of NO and its atmospheric oxidation products) aboard civil in-service aircraft in the framework of MOZAIC is described. The instrument employs the detection of NO by its chemiluminescence with O3 in combination with catalytic conversion of the other NOy compounds to NO at 300°C on a gold surface in the presence of H2. The instrument has a sensitivity of 0.4-0.7cps/ppt and is designed for unattended operation during 1-2 service cycles of the aircraft (400-800 flight hours). The total weight is 50kg, including calibration system, compressed gases, mounting, and safety measures. The layout and inlet configuration are governed by requirements due to the certification for passenger aircraft. Laboratory tests are described regarding the conversion efficiency for NO2 and HNO3 (both >98%). Interference by non-NOy species is <1% for CH3CN and NH3, <5x10-5% for N2O (corresponding to <0.2ppt fake NOy from ambient N2O) and 100% for HCN. The time response of the instrument is <1s (90% change) for NO2. The response for HNO3 is nonlinear: 20s for 67%, 60s for 80%, and 150s for 90% response, respectively.

  18. Comparison of Satellite and Aircraft Measurements of Cloud Microphysical Properties in Icing Conditions During ATREC/AIRS-II

    NASA Technical Reports Server (NTRS)

    Nguyen, Louis; Minnis, Patrick; Spangenberg, Douglas A.; Nordeen, Michele L.; Palikonda, Rabindra; Khaiyer, Mandana M.; Gultepe, Ismail; Reehorst, Andrew L.

    2004-01-01

    Satellites are ideal for continuous monitoring of aircraft icing conditions in many situations over extensive areas. The satellite imager data are used to diagnose a number of cloud properties that can be used to develop icing intensity indices. Developing and validating these indices requires comparison with objective "cloud truth" data in addition to conventional pilot reports (PIREPS) of icing conditions. Minnis et al. examined the relationships between PIREPS icing and satellite-derived cloud properties. The Atlantic-THORPEX Regional Campaign (ATReC) and the second Alliance Icing Research Study (AIRS-II) field programs were conducted over the northeastern USA and southeastern Canada during late 2003 and early 2004. The aircraft and surface measurements are concerned primarily with the icing characteristics of clouds and, thus, are ideal for providing some validation information for the satellite remote sensing product. This paper starts the process of comparing cloud properties and icing indices derived from the Geostationary Operational Environmental Satellite (GOES) with the aircraft in situ measurements of several cloud properties during campaigns and some of the The comparisons include cloud phase, particle size, icing intensity, base and top altitudes, temperatures, and liquid water path. The results of this study are crucial for developing a more reliable and objective icing product from satellite data. This icing product, currently being derived from GOES data over the USA, is an important complement to more conventional products based on forecasts, and PIREPS.

  19. A broadband cavity enhanced absorption spectrometer for aircraft measurements of glyoxal, methylglyoxal, nitrous acid, nitrogen dioxide, and water vapor

    NASA Astrophysics Data System (ADS)

    Min, K.-E.; Washenfelder, R. A.; Dubé, W. P.; Langford, A. O.; Edwards, P. M.; Zarzana, K. J.; Stutz, J.; Lu, K.; Rohrer, F.; Zhang, Y.; Brown, S. S.

    2016-02-01

    We describe a two-channel broadband cavity enhanced absorption spectrometer (BBCEAS) for aircraft measurements of glyoxal (CHOCHO), methylglyoxal (CH3COCHO), nitrous acid (HONO), nitrogen dioxide (NO2), and water (H2O). The instrument spans 361-389 and 438-468 nm, using two light-emitting diodes (LEDs) and a single grating spectrometer with a charge-coupled device (CCD) detector. Robust performance is achieved using a custom optical mounting system, high-power LEDs with electronic on/off modulation, high-reflectivity cavity mirrors, and materials that minimize analyte surface losses. We have successfully deployed this instrument during two aircraft and two ground-based field campaigns to date. The demonstrated precision (2σ) for retrievals of CHOCHO, HONO and NO2 are 34, 350, and 80 parts per trillion (pptv) in 5 s. The accuracy is 5.8, 9.0, and 5.0 %, limited mainly by the available absorption cross sections.

  20. A broadband cavity enhanced absorption spectrometer for aircraft measurements of glyoxal, methylglyoxal, nitrous acid, nitrogen dioxide, and water vapor

    NASA Astrophysics Data System (ADS)

    Min, K.-E.; Washenfelder, R. A.; Dubé, W. P.; Langford, A. O.; Edwards, P. M.; Zarzana, K. J.; Stutz, J.; Lu, K.; Rohrer, F.; Zhang, Y.; Brown, S. S.

    2015-10-01

    We describe a two-channel broadband cavity enhanced absorption spectrometer (BBCEAS) for aircraft measurements of glyoxal (CHOCHO), methylglyoxal (CH3COCHO), nitrous acid (HONO), nitrogen dioxide (NO2), and water (H2O). The instrument spans 361-389 and 438-468 nm, using two light emitting diodes (LEDs) and a grating spectrometer with a charge-coupled device (CCD) detector. Robust performance is achieved using a custom optical mounting system, high power LEDs with electronic on/off modulation, state-of-the-art cavity mirrors, and materials that minimize analyte surface losses. We have successfully deployed this instrument during two aircraft and two ground-based field campaigns to date. The demonstrated precision (2σ) for retrievals of CHOCHO, HONO and NO2 are 34, 350 and 80 pptv in 5 s. The accuracy is 5.8, 9.0 and 5.0 % limited mainly by the available absorption cross sections.

  1. Total ozone derived from UV spectrophotometer measurements on the NASA CV-990 aircraft for the fall 1976 latitude survey flights

    NASA Technical Reports Server (NTRS)

    Hanser, F. A.

    1977-01-01

    An ultraviolet interference filter spectrophotometer was modified to use a photodiode and was flown on latitude survey flights in the fall of 1976. Comparison with Dobson station total ozone values shows agreement between UVS and Dobson total ozone of + or - 2 percent. The procedure used to convert UVS measured ozone above the aircraft altitude to total ozone above ground level introduces an additional 2 percent deviation for very high altitude UVS ozone data. Under stable aircraft operating conditions, the UVS derived ozone values have a variability, or reproducibility, of better than + or -1 percent. The UVS data from the latitude survey flights yield a detailed latitude profile of total ozone over the Pacific Ocean during November 1976. Significant latitudinal structure in total ozone is found at the middle latitudes (30 deg to 40 deg N and S).

  2. Jet-engine combustor spectral radiation measurements using fiberoptic instrumentation system. Radiant energy power source for jet aircraft. Final report

    SciTech Connect

    Doellner, O.L.

    1986-02-01

    This report is a summary of spectral radiation measurements made at Williams Air Force Base, Chandler, Arizona on a General Electric J-85-5 engine. The spectral radiation measurements consisted of a complete axial profile down the combustor and are directed toward the application of Radiant Energy Power Source for Jet Aircraft. Radiant Energy Power Source for Jet Aircraft relates to the use of photovoltaic cells to generate the electrical power demands of the aircraft. The photovoltaic cells are mounted inside the casing of the jet engine, are thermally insulated from the normally hot engine casing, and are appropriately cooled. The photovoltaic cells receive their required radiant energy from the combustion flame by holes in the combustion liner. The instrumentation system used to make these measurements employed fiberoptic probes - entering the engine by way of an existing (modified) access plate - to obtain the radiation measurements. Such an instrumentation system has the strong advantage of being able to measure radiation from all the holes running axially down the combustor without making any holes in the plenum/engine casing - as would be necessary if sapphire observation windows were used. This report is thus more than a discussion of spectral radiation measurements made on a jet engine: it is also a report of the design and evolution of the fiberoptic instrumentation system used to make these measurements. The instrumentation system was designed and built from fundamental first principles, as described in detail in this report. It is believed that this fiberoptic instrumentation system will find application with gas-turbine manufacturers.

  3. Aircraft landing gear systems

    NASA Technical Reports Server (NTRS)

    Tanner, John A. (Editor)

    1990-01-01

    Topics presented include the laboratory simulation of landing gear pitch-plane dynamics, a summary of recent aircraft/ground vehicle friction measurement tests, some recent aircraft tire thermal studies, and an evaluation of critical speeds in high-speed aircraft. Also presented are a review of NASA antiskid braking research, titanium matrix composite landing gear development, the current methods and perspective of aircraft flotation analysis, the flow rate and trajectory of water spray produced by an aircraft tire, and spin-up studies of the Space Shuttle Orbiter main gear tire.

  4. Dynamic measurement of drilling fluid rheology at elevated temperature and pressure

    SciTech Connect

    Moussa, M.M.; Al-Marhoun, M.A.

    1985-03-01

    Due to instability and degradation of the conventional drilling fluids specially under high shear rate, elevated temperatures and chemically complex environments of deep and geothermal wells, it is essential to modify and develop stable batches of clay suspensions that can perform adequately under these conditions. To obtain batches, a reliable set-up should be designed and constructed to examine and measure all the properties that may possibly change under the prevailing conditions. A scaled dynamic flow loop is designed and built in the Department of Petroleum Engineering at the University of Petroleum and Minerals, Dhahran. This set-up can simulate efficiently the bottomhole condition e.g. high temperature up to 450/sup 0/F, high shear rate up to 50,000 sec/sup -1/. The system pressure is maintained above the saturation pressure of water at the test temperature. Dynamic filteration rate and the corrosion rate is monitored instantaneously at wide range of bottomhole conditions. The flow parameters NandK,/tau/, ..gamma.. etc., are obtained by measuring ..delta..P across the 3-tube viscometer using the DP 15-150 pressure differential transducers. The ambient properties are measured by Baroid multi-speed viscometer and compared with data obtained from the loop. Two batches composed of sepiolite and polymer were tested. Effective viscosity is increased significantly at high temperature for the first and second batches. The consistency and thermal stability of these fluids may be attributed to the transfer of sepiolite to smectite at high temperature and high shear.

  5. Clear Sky Column Closure Studies of Urban-Marine and Mineral-Dust Aerosols Using Aircraft, Ship, Satellite and Ground-Based Measurements in ACE-2

    NASA Technical Reports Server (NTRS)

    Schmid, Beat; Russell, Philip B.; Livingston, John M.; Gasso, Santiago; Hegg, Dean A.; Collins, Donald R.; Flagan, Richard C.; Seinfeld, John H.; Oestroem, Elisabeth; Noone, Kevin J.; Durkee, Philip A.; Jonsson, Haflidi H.; Welton, Ellsworth J.; Voss, Kenneth J.; Gordon, Howard R.; Formenti, Paola; Andreae, Meinrat O.; Kapustin, Vladimir N.; Bates, Timothy S.; Quinn, Patricia K.

    2000-01-01

    As part of the second Aerosol Characterization Experiment (ACE-2), European urban-marine and African mineral-dust aerosols were measured aboard the Pelican aircraft, the Research Vessel Vodyanitskiy from the ground and from satellites.

  6. Application of a cost/performance measurement system on a research aircraft project

    NASA Technical Reports Server (NTRS)

    Diehl, J. J.

    1978-01-01

    The fundamentals of the cost/performance management system used in the procurement of two tilt rotor aircraft for a joint NASA/Army research project are discussed. The contractor's reporting system and the GPO's analyses are examined. The use of this type of reporting system is assessed. Recommendations concerning the use of like systems on future projects are included.

  7. A test and measurement technique for determining possible lightning-induced voltages in aircraft electrical circuits

    NASA Technical Reports Server (NTRS)

    Plumer, J. A.; Walko, L. C.

    1975-01-01

    Transient analyzer consists of four 0.5 microfarads capacitors chargeable by self-contained solid state 50 KV dc power supply operating from standard 110 Vac line voltage. Unit can circulate unidirectional current impulses of up to 500 amperes through aircraft at waveshapes similar to those of natural lightning strokes.

  8. Measures to increase airfield capacity by changing aircraft runway occupancy characteristics

    NASA Technical Reports Server (NTRS)

    Gosling, G. D.; Kanafani, A.; Rockaday, S. L. M.

    1981-01-01

    Airfield capacity and aircraft runway occupancy characteristics were studied. Factors that caused runway congestion and airfield crowding were identified. Several innovations designed to alleviate the congestion are discussed. Integrated landing management, the concept that the operation of the final approach and runway should be considered in concert, was identified as underlying all of the innovations.

  9. Evaluating source area contributions from aircraft flux measurements over heterogeneous land cover by large eddy simulation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The estimation of spatial patterns in surface fluxes from aircraft observations poses several challenges in presence of heterogeneous land cover. In particular, the effects of turbulence on scalar transport and the different behavior of passive (e.g. moisture) versus active (e.g. temperature) scalar...

  10. A STUDY OF EXTRACTIVE AND REMOTE-SENSING SAMPLING AND MEASUREMENT OF EMISSIONS FROM MILITARY AIRCRAFT ENGINES

    SciTech Connect

    Cheng, Mengdawn; Corporan, E.

    2010-01-01

    Aircraft emissions contribute to the increased atmospheric burden of particulate matter (e.g., black carbon and secondary organic compounds) that plays a role in air quality, contrail formation and climate change. Sampling and measurement of modern aircraft emissions at the engine exhaust plane (EEP) for to engine and fuel certification remains a daunting task, no agency-certified method is available for the task. In this paper we summarize the results of a recent study that was devoted to investigate both extractive and optical remote-sensing (ORS) technologies in sampling and measurement of gaseous and particulate matter (PM) emitted by a number of military aircraft engines operated with JP-8 and a Fischer-Tropsch (FT) fuel at various engine conditions. These engines include cargo, bomber, and helicopter types of military aircraft that consumes 70-80% of the military aviation fuel each year. The emission indices of selected pollutants are discussed as these data may be of interest for atmospheric modeling and for design of air quality control strategies around the airports and military bases. It was found that non-volatile particles in the engine emissions were all in the ultrafine range. The mean diameter of particles increased as the engine power increased; the mode diameters were in the 20nm range for the low power condition of a new helicopter engine to 80nm for the high power condition of a newly maintained bomber engine. Elemental analysis indicated little metals were present on particles in the exhaust, while most of the materials on the exhaust particles were based on carbon and sulfate. Carbon monoxide, carbon dioxide, nitrogen oxide, sulfur dioxide, formaldehyde, ethylene, acetylene, propylene, and alkanes were detected using both technologies. The last five species (in the air toxics category) were most noticeable only under the low engine power. The emission indices calculated based on the ORS data were however observed to differ significantly (up to

  11. Measurement of Turbulent Water Vapor Fluxes from Lightweight Unmanned Aircraft Systems

    NASA Astrophysics Data System (ADS)

    Thomas, R. M.; Ramanathan, V.; Nguyen, H.; Lehmann*, K.

    2010-12-01

    Scientists at the Center for Clouds, Chemistry and Climate (C4) at the Scripps Institution of Oceanography have successfully used Unmanned Aircraft Systems (UASs) for measurements of radiation fluxes, aerosol concentrations and cloud microphysical properties. Building on this success, a payload to measure water vapor fluxes using the eddy covariance (EC) technique has been recently developed and tested. To our knowledge this is the first UAS turbulent flux system to incorporate high-frequency water vapor measurements. The driving aim of the water vapor flux system’s development is to investigate ‘atmospheric rivers’ in the north-western Pacific Ocean, these can lead to sporadic yet extreme rainfall and flooding events upon landfall in California. Such a flux system may also be used to investigate other weather events (e.g. the formation of hurricanes) and offers a powerful aerosol-cloud-radiative forcing investigative tool when combined with the existing aerosol/radiation and cloud microphysics UAS payloads. The atmospheric vertical wind component (w) is derived by this system at up to 100Hz using data from a GPS/Inertial Measurement Unit (GPS/IMU) combined with a fast-response gust probe mounted on the UAV. Measurements of w are then combined with equally high frequency water vapor data (collected using a Campbell Scientific Krypton Hygrometer) to calculate latent heat fluxes (λE). Two test flights were conducted at the NASA Dryden test facility on 27th May 2010, located in the Mojave Desert. Horizontal flight legs were recorded at four altitudes between 1000-2500 masl within the convective boundary layer. Preliminary data analysis indicates averaged spectral data follow the theoretical -5/3 slope , and extrapolation of the flux profile to the surface resulted in λE of 1.6 W m-2; in good agreement with 1.0 W m-2 λE measured by NOAA from a surface tower using standard flux techniques. The system performance during the Dryden test, as well as subsequent

  12. Development and Deployment of an Aerospace Recommended Practice (ARP) Compliant Measurement System for nvPM Certification Measurements of Aircraft Engines - Current Status.

    NASA Astrophysics Data System (ADS)

    Whitefield, P. D.; Hagen, D. E.; Lobo, P.; Miake-Lye, R. C.

    2015-12-01

    The Society of Automotive Engineers (SAE) Aircraft Exhaust Emissions Measurement Committee (E-31) has published an Aerospace Information Report (AIR) 6241 detailing the sampling system for the measurement of non-volatile particulate matter (nvPM) from aircraft engines (SAE 2013). The system is designed to operate in parallel with existing International Civil Aviation Organization (ICAO) Annex 16 compliant combustion gas sampling systems used for emissions certification from aircraft engines captured by conventional (Annex 16) gas sampling rakes (ICAO, 2008). The SAE E-31 committee is also working to ballot an Aerospace Recommended Practice (ARP) that will provide the methodology and system specification to measure nvPM from aircraft engines. The ARP is currently in preparation and is expected to be ready for ballot in 2015. A prototype AIR-compliant nvPM measurement system - The North American Reference System (NARS) has been built and evaluated at the MSTCOE under the joint sponsorship of the FAA, EPA and Transport Canada. It has been used to validate the performance characteristics of OEM AIR-compliant systems and is being used in engine certification type testing at OEM facilities to obtain data from a set of representative engines in the fleet. The data collected during these tests will be used by ICAO/CAEP/WG3/PMTG to develop a metric on which on the regulation for nvPM emissions will be based. This paper will review the salient features of the NARS including: (1) emissions sample transport from probe tip to the key diagnostic tools, (2) the mass and number-based diagnostic tools for nvPM mass and number concentration measurement and (3) methods employed to assess the extent of nvPM loss throughout the sampling system. This paper will conclude with a discussion of the recent results from inter-comparison studies conducted with other US - based systems that gives credence to the ARP's readiness for ballot.

  13. Method of radial velocities for the estimation of aircraft wake vortex parameters from data measured by coherent Doppler lidar.

    PubMed

    Smalikho, I N; Banakh, V A; Holzäpfel, F; Rahm, S

    2015-09-21

    The method of radial velocities (RV) is applied to estimate aircraft wake vortex parameters from measurements conducted with pulsed coherent Doppler lidar (PCDL). Operations of the Stream Line lidar and the 2-µm PCDL are simulated numerically to analyze the accuracy of the estimated wake vortex parameters with the RV method. The RV method is also used to estimate wake vortex trajectories and circulation from lidar measurements at Tomsk and Munich airports. The method of velocity envelopes and the RV method are compared employing data gathered with the 2-µm PCDL. The domain of applicability of the RV method is determined.

  14. Rheological and Mechanical Property Measurements of PMDI Foam at Elevated Temperatures

    SciTech Connect

    Nemer, Martin Bernard; Brooks, Carlton F.; Shelden, Bion; Soehnel, Melissa Marie; Barringer, David Alan

    2014-10-01

    A study was undertaken to determine the viscosity of liquefied 20 lb/ft3 poly methylene diisocyanate (PMDI) foam and the stress required to puncture solid PMDI foam at elevated temperatures. For the rheological measurements the foam was a priori liquefied in a pressure vessel such that the volatiles were not lost in the liquefaction process. The viscosity of the liquefied PMDI foam was found to be Newtonian with a power law dependence on temperature log10(μ/Pa s) = 20.6 – 9.5 log10(T/°C) for temperatures below 170 °C. Above 170 °C, the viscosity was in the range of 0.3 Pa s which is close to the lower measurement limit (≈ 0.1 Pa s) of the pressurized rheometer. The mechanical pressure required to break through 20lb/ft3 foam was 500-800 psi at temperatures from room temperature up to 180 °C. The mechanical pressure required to break through 10 lb/ft3 was 170-300 psi at temperatures from room temperature up to 180 °C. We have not been able to cause gas to break through the 20 lb/ft3 PMDI foam at gas pressures up to 100 psi.

  15. Investigation of a laser Doppler velocimeter system to measure the flow field around a large scale V/STOL aircraft in ground effect

    NASA Technical Reports Server (NTRS)

    Zalay, A. D.; Brashears, M. R.; Jordan, A. J.; Shrider, K. R.; Vought, C. D.

    1979-01-01

    The flow field measured around a hovering 70 percent scale vertical takeoff and landing (V/STOL) aircraft model is described. The velocity measurements were conducted with a ground based laser Doppler velocimeter. The remote sensing instrumentation and experimental tests of the velocity surveys are discussed. The distribution of vertical velocity in the fan jet and fountain; the radial velocity in the wall jet and the horizontal velocity along the aircraft underside are presented for different engine rpms and aircraft height above ground. Results show that it is feasible to use a mobile laser Doppler velocimeter to measure the flow field generated by a large scale V/STOL aircraft operating in ground effect.

  16. Investigation of a laser Doppler velocimeter system to measure the flow field of a large scale V/STOL aircraft in ground effect

    NASA Technical Reports Server (NTRS)

    Zalay, A. D.; Brashears, M. R.; Jordan, A. J.; Shrider, K. R.; Vought, C. D.

    1979-01-01

    An experimental research program for measuring the flow field around a 70 percent scale V/STOL aircraft model in ground effect is described. The velocity measurements were conducted with a ground-based laser Doppler velocimeter at an outdoor test pad. The remote sensing instrumentation, experimental tests, and results of the velocity surveys are discussed. The distribution of vertical velocity in the fan jet and fountain, the radial velocity in the wall jet and the horizontal velocity along the aircraft underside are presented for different engine rpms and aircraft heights above ground. The study shows that it is feasible to use a mobile laser Doppler velocimeter to measure the flow field generated by a large scale V/STOL aircraft operating in ground effect.

  17. Using aircraft eddy-covariance measurements to examine the spatial heterogeneity of CO2 exchange above three temperate forests

    NASA Astrophysics Data System (ADS)

    Caulton, D.; Shepson, P. B.; Hollinger, D. Y.; Munger, J. W.; Saatchi, S. S.; Moghaddam, M.; Moorcroft, P. R.; Metzger, S.; Stirm, B. H.

    2014-12-01

    Regional and global scale ecosystem models often rely on data from flux towers to simulate the surface-atmosphere exchange of CO2. Such data represent comparatively small source areas (~1 km2) and in many cases exhibit relatively homogeneous land use and surface characteristics. This approach assumes that the small-scale observations yield representative results for larger regions that can be more heterogeneous in terms of land cover, soil moisture, topography and climatology. To complement this data source, aircraft platforms can be used to provide snapshot views of land cover and meteorological properties. Moreover, aircraft provide access to essentially any environment including remote and heterogeneous regions. Here, we used an instrumented aircraft platform equipped with a 50 Hz wind probe, Global Navigation Satellite System/Inertial Measurement Unit and a 10 Hz Picarro CO2/H2O analyzer. Applying the eddy-covariance technique, this platform permits determining the surface-atmosphere exchange of heat and CO2 fluxes over larger (~101-102 km2) spatial scales. Specifically, thirty-eight flux measurement experiments were conducted as part of the Airborne Observatory of Subcanopy and Subsurface (AirMOSS) campaigns in July, 2012 and May-August, 2013. Each experiment targeted specific land cover types over and near Howland Forest, ME, Harvard Forest, MA and Duke Forest, NC. A footprint parameterization is used to determine the contribution of different surface sources to the flux measurements. The surface area contributing to the measured fluxes is typically on the order of 37 ± 17 km2, with 90% of the contributions being sourced from within an upwind distance of 1.9 ± 0.8 km. Combining the knowledge of these source areas with land cover and soil moisture data from the NASA G-III aircraft enables investigating the influence of surface heterogeneity on the measured fluxes. Lastly, the measured fluxes are compared to simulated CO2 fluxes from the Ecosystem Demography

  18. Tunable diode laser in-situ CH4 measurements aboard the CARIBIC passenger aircraft: instrument performance assessment

    NASA Astrophysics Data System (ADS)

    Dyroff, C.; Zahn, A.; Sanati, S.; Christner, E.; Rauthe-Schöch, A.; Schuck, T. J.

    2014-03-01

    A laser spectrometer for automated monthly measurements of methane (CH4) mixing ratios aboard the CARIBIC passenger aircraft is presented. The instrument is based on a commercial Fast Greenhouse Gas Analyser (FGGA, Los Gatos Res.), which was adapted to meet the requirements imposed by unattended airborne operation. It was characterised in the laboratory with respect to instrument stability, precision, cross sensitivity to H2O, and accuracy. For airborne operation, a calibration strategy is described that utilises CH4 measurements obtained from flask samples taken during the same flights. The precision of airborne measurements is 2 ppb for 10 s averages. The accuracy at aircraft cruising altitude is 3.85 ppb. During aircraft ascent and descent, where no flask samples were obtained, instrumental drifts can be less accurately determined and the uncertainty is estimated to be 12.4 ppb. A linear humidity bias correction was applied to the CH4 measurements, which was most important in the lower troposphere. On average, the correction bias was around 6.5 ppb at an altitude of 2 km, and negligible at cruising flight level. Observations from 103 long-distance flights are presented that span a large part of the northern hemispheric upper troposphere and lowermost stratosphere (UT/LMS), with occasional crossing of the tropics on flights to southern Africa. These accurate data mark the largest UT/LMS in-situ CH4 dataset worldwide. An example of a tracer-tracer correlation study with ozone is given, highlighting the possibility for accurate cross-tropopause transport analyses.

  19. Tunable diode laser in-situ CH4 measurements aboard the CARIBIC passenger aircraft: instrument performance assessment

    NASA Astrophysics Data System (ADS)

    Dyroff, C.; Zahn, A.; Sanati, S.; Christner, E.; Rauthe-Schöch, A.; Schuck, T. J.

    2013-10-01

    A laser spectrometer for automated monthly measurements of methane (CH4) mixing ratios aboard the CARIBIC passenger aircraft is presented. The instrument is based on a commercial Fast Greenhouse Gas Analyzer (FGGA, Los Gatos Res.), which was adapted to meet the requirements imposed by unattended airborne employment. The modified instrument is described. A laboratory characterization was performed to determine the instrument stability, precision, cross sensitivity to H2O, and accuracy. For airborne operation a calibration strategy is described, that utilizes CH4 measurements obtained from flask samples taken during the same flights. The precision of airborne measurements is 2 ppbv for 10 s averages. The accuracy at aircraft cruising altitude is 3.85 ppbv. During aircraft ascent and descent, where no flask samples were obtained, instrumental drifts can be less accurately considered and the uncertainty is estimated to be 12.4 ppbv. A linear humidity bias correction was applied to the CH4 measurements, which was most important in the lower troposphere. On average, the correction bias was around 6.5 ppbv at an altitude of 2 km, and negligible at cruising flight level. Observations from 103 long-distance flights are presented that span a large part of the northern hemispheric upper troposphere and lowermost stratosphere (UT/LMS), with occasional crossing of the tropics on flights to southern Africa. These accurate data mark the largest UT/LMS in-situ CH4 dataset worldwide. An example of a tracer-tracer correlation study with ozone is given, highlighting the possibility for accurate cross-tropopause transport analyses.

  20. Water Uptake and Carbon Assimilation in Maize at Elevated and ambient CO2: Modeling and Measurement.

    NASA Astrophysics Data System (ADS)

    Timlin, Dennis; Chun, Jong-Ahn; Kim, Soo-Hyung; Yang, Yang; Fleisher, David; Reddy, Vangimalla

    2013-04-01

    Potential transpiration in crops is dependent on both plant and environmental properties. Carbon dioxide content of the atmosphere is linked to potential transpiration because CO2 diffuses onto water saturated surfaces within plant stomata. At high CO2 concentrations, CO2 diffuses rapidly into stomata and therefore stomata do not have to remain open to the atmosphere for long periods of time. This results in lower transpiration rates per unit CO2 assimilated at elevated CO2 concentrations. The objective of this study was to measure CO2 assimilation and water uptake by maize under different irrigation regimes and two CO2 concentrations. The data were then used to evaluate the ability of the maize model MaizSim to simulate the effects of water stress and CO2 on water use and photosynthesis. MaizSim uses a Farquhar type photosynthesis model coupled a Ball-Berry stomatal control model. Non-linear beta functions are used to estimate the effects of temperature on growth and development processes. The experimental data come from experiments in outdoor, sunlit growth chambers at the USDA-ARS Beltsville Agricultural Research Center. The eight treatments comprised two levels of carbon dioxide concentrations (400 and 800 ppm) and four levels of water stress (well-watered control, mild, moderate, and severe). The water stress treatments were applied at both CO2 levels. Water contents were monitored hourly by a Time Domain Reflectometry (TDR) system. The model simulated higher water contents at the same time after applying water stress at the high CO2 treatment than for the low CO2 treatment as was found in the measured data. Measurement of water uptake by roots and carbon assimilation rates in the chambers will be addressed.

  1. A Performance Measurement System for the Aircraft Intermediate Maintenance Department Officer

    DTIC Science & Technology

    1976-06-01

    Air Station or ship and performs intermediate level maintenance on aircraft remuovable V components such as engines, avionic ec•uipment, ejection...seats, etc. In resource management terminolcgy, a shore-based AIMD is Al a cost center of a Naval Air Station which is designated as a responsibility...parent Naval Air Station . Thus, the purpose of the management control process is to accomplish the stated organizational objectives, effectively and

  2. Moisture and heat budgets of a cirrus cloud from aircraft measurements during FIRE

    NASA Technical Reports Server (NTRS)

    Gultepe, Ismail; Rao, Gandikota V.

    1993-01-01

    This study is based on the NCAR King Air aircraft and radiosonde observations on 31 October 1986 during the FIRE in Wisconsin over Oshkosh. Aircraft step-up and spiral descent flights are used to obtain kinematic and thermodynamic data. In the step-up maneuver, six different penetrations were made between 1528 and 1616 UTC. Each penetration was about 30 km long separated in the vertical by about 300 m. The time difference between the two spiral soundings was about 43 min. The aircraft descended at a rate of 1.5 m/s during these spiral soundings. Kinematic, cloud physical, and radiometric observations from various instruments are used to estimate the different terms in the moisture- and heat-budget equations. The results show that the advection terms, estimated using the mean longitudinal wind and vertical velocities, and radiative fluxes are important in forming budgets for the cirrus layers. Ice-crystal growth is significant in the upper layers. The maintenance of cirrus can be attributed to relatively warm and moist air advection, radiative cooling at upper levels, and moisture advection in the vertical. Turbulent heat and moisture fluxes are found to be significant in the low levels of cirrus.

  3. A comparison of in-situ aircraft measurements of carbon dioxide to GOSAT data measured over Railroad Valley playa, Nevada, USA

    NASA Astrophysics Data System (ADS)

    Tadić, J. M.; Loewenstein, M.; Frankenberg, C.; Iraci, L. T.; Yates, E. L.; Gore, W.; Kuze, A.

    2012-08-01

    In this paper we report vertical profiles of CO2 measured with a cavity ring-down spectrometer (CRDS, Picarro, Inc., 2301-m) on a research aircraft from near ground level to 8 km above mean sea level (a.m.s.l.). The airborne platform employed in this study is an Alpha Jet aircraft operated from NASA Ames Research Center. Flights were undertaken to Railroad Valley, Nevada, USA, to coincide with overpasses of the Greenhouse Gases Observing Satellite (GOSAT). Ground based CO2 was simultaneously measured using CRDS, also at the time and location of the airborne and satellite measurements. Results of three GOSAT coordinated aircraft profiles and ground based measurements in June 2011 are presented and discussed in this paper. The accuracy of the CO2 measurements has been determined based upon laboratory calibrations (WMO traceable standard) and pressure/temperature flight simulations in a test chamber. The 2-σ error bars for the CO2 data presented here are ± 0.4 ppm. Our column CO2 measurements, which include about 85% of the tropospheric mass, are extrapolated, using two different techniques, to include the remainder of the tropospheric and stratospheric CO2. The data are then analyzed using the ACOS (Atmospheric CO2 observations from space; JPL algorithm used to analyze XCO2 from GOSAT data) averaging kernels. ACOS version 2.9 is used to interpret the GOSAT data in a collaborative effort between JPL and the GOSAT team. Column averaged CO2, XCO2, measured by GOSAT and analyzed from our data ranged from 388.1 to 390.5 ppm. Values of XCO2 determined from our Alpha Jet measurements and from the GOSAT on three overflight days agree within 1 ppm or better (<0.3%).

  4. Full-field measurement of surface topographies and thin film stresses at elevated temperatures by digital gradient sensing method.

    PubMed

    Zhang, Changxing; Qu, Zhe; Fang, Xufei; Feng, Xue; Hwang, Keh-Chih

    2015-02-01

    Thin film stresses in thin film/substrate systems at elevated temperatures affect the reliability and safety of such structures in microelectronic devices. The stresses result from the thermal mismatch strain between the film and substrate. The reflection mode digital gradient sensing (DGS) method, a real-time, full-field optical technique, measures deformations of reflective surface topographies. In this paper, we developed this method to measure topographies and thin film stresses of thin film/substrate systems at elevated temperatures. We calibrated and compensated for the air convection at elevated temperatures, which is a serious problem for optical techniques. We covered the principles for surface topography measurements by the reflection mode DGS method at elevated temperatures and the governing equations to remove the air convection effects. The proposed method is applied to successfully measure the full-field topography and deformation of a NiTi thin film on a silicon substrate at elevated temperatures. The evolution of thin film stresses obtained by extending Stoney's formula implies the "nonuniform" effect the experimental results have shown.

  5. A high precision instrument to measure angular and binocular deviation introduced by aircraft windscreens by using a shadow casting technique

    SciTech Connect

    Shivananju, B. N.; Yamdagni, S.; Vasu, R. M.; Asokan, S.

    2012-12-15

    Objects viewed through transparent sheets with residual non-parallelism and irregularity appear shifted and distorted. This distortion is measured in terms of angular and binocular deviation of an object viewed through the transparent sheet. The angular and binocular deviations introduced are particularly important in the context of aircraft windscreens and canopies as they can interfere with decision making of pilots especially while landing, leading to accidents. In this work, we have developed an instrument to measure both the angular and binocular deviations introduced by transparent sheets. This instrument is especially useful in the qualification of aircraft windscreens and canopies. It measures the deviation in the geometrical shadow cast by a periodic dot pattern trans-illuminated by the distorted light beam from the transparent test specimen compared to the reference pattern. Accurate quantification of the shift in the pattern is obtained by cross-correlating the reference shadow pattern with the specimen shadow pattern and measuring the location of the correlation peak. The developed instrument is handy to use and computes both angular and binocular deviation with an accuracy of less than {+-}0.1 mrad ( Almost-Equal-To 0.036 mrad) and has an excellent repeatability with an error of less than 2%.

  6. Dopamine D2High receptors measured ex vivo are elevated in amphetamine-sensitized animals.

    PubMed

    Seeman, Philip

    2009-03-01

    Although dopamine supersensitivity is a fundamental aspect of diseases such as schizophrenia and Parkinson's disease, the molecular basis of dopamine supersensitivity is not known. Because behavioral dopamine supersensitivity is associated with a marked elevation of striatal dopamine D2(High) receptors in vitro, it is important to develop methods to measure D2(High) receptors in vivo. The present ex vivo study found that the dopamine agonist NPA ([-]-N-propyl-norapomorphine) inhibited the binding of the agonist [(3)H](+)PHNO to rat striatal D2 receptors significantly more than the D2 antagonist [(3)H]raclopride, when NPA was coinjected i.v. with each radioligand. These results suggest that the greater sensitivity of [(3)H](+)PHNO to inhibition by the coinjected NPA reflects in vivo competition at D2(High) receptors. Using rats that had been sensitized to amphetamine, this ex vivo method found that the specific binding of [(3)H](+)PHNO that was displaced by 10 microg/kg of NPA was 2.4-fold higher than that for control rats. These data agree with in vitro data showing a marked increase in D2(High) sites after amphetamine sensitization. Therefore, it is recommended that this method of co-injecting the D2 radioligand and the dopamine agonist displacer be used in human positron tomography to detect D2(High) receptors in health and disease.

  7. Using smartphone pressure sensors to measure vertical velocities of elevators, stairways, and drones

    NASA Astrophysics Data System (ADS)

    Monteiro, Martín; Martí, Arturo C.

    2017-01-01

    We measure the vertical velocities of elevators, pedestrians climbing stairs, and drones (flying unmanned aerial vehicles), by means of smartphone pressure sensors. The barometric pressure obtained with the smartphone is related to the altitude of the device via the hydrostatic approximation. From the altitude values, vertical velocities are derived. The approximation considered is valid in the first hundred meters of the inner layers of the atmosphere. In addition to pressure, acceleration values were also recorded using the built-in accelerometer. Numerical integration was performed, obtaining both vertical velocity and altitude. We show that data obtained using the pressure sensor is significantly less noisy than that obtained using the accelerometer. Error accumulation is also evident in the numerical integration of the acceleration values. In the proposed experiments, the pressure sensor also outperforms GPS, because this sensor does not receive satellite signals indoors and, in general, the operating frequency is considerably lower than that of the pressure sensor. In the cases in which it is possible, comparison with reference values taken from the architectural plans of buildings validates the results obtained using the pressure sensor. This proposal is ideally performed as an external or outreach activity with students to gain insight about fundamental questions in mechanics, fluids, and thermodynamics.

  8. Instrumentation and measurement strategy for the NOAA SENEX aircraft campaign as part of the Southeast Atmosphere Study 2013

    NASA Astrophysics Data System (ADS)

    Warneke, Carsten; Trainer, Michael; de Gouw, Joost A.; Parrish, David D.; Fahey, David W.; Ravishankara, A. R.; Middlebrook, Ann M.; Brock, Charles A.; Roberts, James M.; Brown, Steven S.; Neuman, Jonathan A.; Lerner, Brian M.; Lack, Daniel; Law, Daniel; Hübler, Gerhard; Pollack, Iliana; Sjostedt, Steven; Ryerson, Thomas B.; Gilman, Jessica B.; Liao, Jin; Holloway, John; Peischl, Jeff; Nowak, John B.; Aikin, Kenneth C.; Min, Kyung-Eun; Washenfelder, Rebecca A.; Graus, Martin G.; Richardson, Mathew; Markovic, Milos Z.; Wagner, Nick L.; Welti, André; Veres, Patrick R.; Edwards, Peter; Schwarz, Joshua P.; Gordon, Timothy; Dube, William P.; McKeen, Stuart A.; Brioude, Jerome; Ahmadov, Ravan; Bougiatioti, Aikaterini; Lin, Jack J.; Nenes, Athanasios; Wolfe, Glenn M.; Hanisco, Thomas F.; Lee, Ben H.; Lopez-Hilfiker, Felipe D.; Thornton, Joel A.; Keutsch, Frank N.; Kaiser, Jennifer; Mao, Jingqiu; Hatch, Courtney D.

    2016-07-01

    Natural emissions of ozone-and-aerosol-precursor gases such as isoprene and monoterpenes are high in the southeastern US. In addition, anthropogenic emissions are significant in the southeastern US and summertime photochemistry is rapid. The NOAA-led SENEX (Southeast Nexus) aircraft campaign was one of the major components of the Southeast Atmosphere Study (SAS) and was focused on studying the interactions between biogenic and anthropogenic emissions to form secondary pollutants. During SENEX, the NOAA WP-3D aircraft conducted 20 research flights between 27 May and 10 July 2013 based out of Smyrna, TN. Here we describe the experimental approach, the science goals and early results of the NOAA SENEX campaign. The aircraft, its capabilities and standard measurements are described. The instrument payload is summarized including detection limits, accuracy, precision and time resolutions for all gas-and-aerosol phase instruments. The inter-comparisons of compounds measured with multiple instruments on the NOAA WP-3D are presented and were all within the stated uncertainties, except two of the three NO2 measurements. The SENEX flights included day- and nighttime flights in the southeastern US as well as flights over areas with intense shale gas extraction (Marcellus, Fayetteville and Haynesville shale). We present one example flight on 16 June 2013, which was a daytime flight over the Atlanta region, where several crosswind transects of plumes from the city and nearby point sources, such as power plants, paper mills and landfills, were flown. The area around Atlanta has large biogenic isoprene emissions, which provided an excellent case for studying the interactions between biogenic and anthropogenic emissions. In this example flight, chemistry in and outside the Atlanta plumes was observed for several hours after emission. The analysis of this flight showcases the strategies implemented to answer some of the main SENEX science questions.

  9. The atmospheric effects of stratospheric aircraft. Report of the 1992 Models and Measurements Workshop. Volume 1: Workshop objectives and summary

    NASA Technical Reports Server (NTRS)

    Prather, Michael J. (Editor); Remsburg, Ellis E. (Editor)

    1993-01-01

    This Workshop on Stratospheric Models and Measurements (M&M) marks a significant expansion in the history of model intercomparisons. It provides a foundation for establishing the credibility of stratospheric models used in environmental assessments of chlorofluorocarbons, aircraft emissions, and climate-chemistry interactions. The core of the M&M comparisons involves the selection of observations of the current stratosphere (i.e., within the last 15 years): these data are believed to be accurate and representative of certain aspects of stratospheric chemistry and dynamics that the models should be able to simulate.

  10. The atmospheric effects of stratospheric aircraft. Report of the 1992 Models and Measurements Workshop. Volume 3: Special diagnostic studies

    NASA Technical Reports Server (NTRS)

    Prather, Michael J. (Editor); Remsberg, Ellis E. (Editor)

    1993-01-01

    This Workshop on Stratospheric Models and Measurements (M&M) marks a significant expansion in the history of model intercomparisons. It provides a foundation for establishing the credibility of stratospheric models used in environmental assessments of chlorofluorocarbons, aircraft emissions, and climate-chemistry interactions. The core of the M&M comparisons involves the selection of observations of the current stratosphere (i.e., within the last 15 years): these data are believed to be accurate and representative of certain aspects of stratospheric chemistry and dynamics that the models should be able to simulate.

  11. Structureborne noise in aircraft

    NASA Technical Reports Server (NTRS)

    Clevenson, S. A.; Metcalf, V. L.

    1987-01-01

    The amount of noise reaching an aircraft's interior by structureborne paths, when high levels of other noises are present, involves the measurement of transfer functions between vibrating levels on the wing and interior noise. The magnitude of the structureborne noise transfer function is established by exciting the aircraft with an electrodynamic shaker; a second transfer function is measured using the same sensor locations with the aircraft engines operating. Attention is given to the case of a twin-turboprop OV-10A aircraft; the resulting transfer function values at the discrete frequencies corresponding to the propeller blade passage frequency and its first four harmonics are tabulated and illustrated.

  12. Science on a space elevator

    SciTech Connect

    Laubscher, B. E.; Jorgensen, A. M.

    2004-01-01

    The Space Elevator (SE) represents a major paradigm shift in space access. If the SE's promise of low cost access can be realized, everything becomes economically more feasible to accomplish in space. In this paper we describe in-situ science stations mounted on a science-dedicated space elevator tether. The concept presented here involves a carbon nanotube ribbon that is constructed by an existing space elevator and then science sensors are stationed along the ribbon at differing altitudes. The finished ribbon can be moved across the earth to the position at which its scientific measurements are to be taken. The ability to station scientific, in-situ instrumentation at different altitudes for round-the-clock observations is a unique capability of the SE. The environments that the science packages sense range from the troposphere out beyond the magnetopause of the magnetosphere on the solar side of the earth. Therefore, the very end of the SE can sense the solar wind. The measurements at various points along its length include temperature, pressure, density, sampling, chemical analyses, wind speed, turbulence, free oxygen, electromagnetic radiation, cosmic rays, energetic particles and plasmas in the earth's magnetosphere and the solar wind. There exist some altitudes that are difficult to access with aircraft or balloons or rockets and so remain relatively unexplored. The space elevator solves these problems and opens these regions up to in-situ measurements. Without the need for propulsion, the SE provides a more benign and pristine environment for atmospheric measurements than available with powered aircraft. Moreover, replacing and upgrading instrumentation is expected to be very cost effective with the SE. Moving and stationing the science SE affords the opportunity to sense multiple regions of the atmosphere. The SE's geosynchronous, orbital motion through the magnetosphere, albeit nominally with Earth's magnetic field, will trace a plane through that region

  13. Investigation of the Sources and Processing of Organic Aerosol over the Central Mexican Plateau from Aircraft Measurements during MILAGRO

    NASA Astrophysics Data System (ADS)

    Decarlo, Peter; Ulbrich, Ingrid; Crounse, John; de Foy, Benjamin; Dunlea, Edward; Aiken, Allison; Wennberg, Paul; Jimenez, Jose-Luis

    2010-05-01

    Organic aerosol (OA) represents approximately half of the submicron aerosol in Mexico City and the Central Mexican Plateau. This study uses the high time resolution measurements performed onboard the NCAR/NSF C-130 aircraft during the MILAGRO/MIRAGE-Mex field campaign in March 2006 to investigate the sources and chemical processing of the OA in this region. An examination of the OA/ΔCO ratio evolution as a function of photochemical age shows distinct behavior in the presence or absence of substantial open biomass burning (BB) influence, with the latter being consistent with other studies in polluted areas. In addition, results from Positive Matrix Factorization (PMF) analysis of 12-second High-Resolution Time-of-Flight Aerosol Mass Spectrometer (HR-ToF-AMS) OA spectra will be presented. Four components were resolved. Three of the components contain substantial organic oxygen and are termed semivolatile oxygenated OA (SV-OOA), low-volatility OOA (LV-OOA), and biomass burning OA (BBOA). A reduced "hydrocarbon-like OA" (HOA) component is also resolved. LV-OOA is highly oxygenated (atomic O/C~1) and is aged organic aerosol linked to regional airmasses, with likely contributions from pollution, biomass burning, and other sources. SV-OOA is strongly correlated with ammonium nitrate, Ox, and the Mexico City Basin. We interpret SV-OOA as secondary OA which is nearly all (>90%) anthropogenic in origin. In the absence of biomass burning it represents the largest fraction of OA over the Mexico City basin, consistent with other studies in this region. BBOA is identified as arising from biomass burning sources due to a strong correlation with HCN, and the elevated contribution of thes ion C2H4O2+ (m/z 60, a marker for levoglucosan and other primary BB species). WRF-FLEXPART calculated fire impact factors (FIF) show good correlation with BBOA mass concentrations within the basin, but show location offsets in the far field due to model transport errors. This component is small

  14. Measurement and treatment of elevated blood pressure in the pediatric patient with chronic kidney disease.

    PubMed

    Swinford, Rita D; Portman, Ronald J

    2004-04-01

    measurement, self-measured BP, and ambulatory BP monitoring. The recommendation for BP measurement in children is, when permitted, by auscultative method with a well-calibrated mercury manometer. Most casual BP measurements are performed with an automated oscillometric device whose validation has not been confirmed in children with CKD. The ambulatory BP monitor (ABPM) has 2 advantages: it significantly correlates with the presence of end-organ damage, and it identifies abnormal BP patterns that are frequently present in CKD patients, such as hypertension during the sleep period. An abnormal ABPM pattern can also be predictive of the development of end-organ damage. Treatment of hypertension in children, with and without CKD, is based on 3 factors: degree of BP elevation, the presence of cardiovascular risk factors, and the presence of end-organ damage. Additionally, the initial antihypertensive agent may be selected on available and age-appropriate formulations (eg, suspension and dosage selection). A physician treating a hypertensive child with CKD faces multiple challenges. They include selecting the convenience of available automated devices and the ABPM versus traditional auscultatory techniques upon which all normative standards have been based. Current research initiatives propose to develop pharmacokinetic and pharmacodynamics properties of antihypertensive medications and to study the effect of early intervention on end-organ damage.

  15. Aircraft measurements of electrified clouds at Kennedy Space Center. Part 2: Case study: 4 November 1988 (88309)

    NASA Technical Reports Server (NTRS)

    Jones, J. J.; Winn, W. P.; Hunyady, S. J.; Moore, C. B.; Bullock, J. W.

    1990-01-01

    During the fall of 1988, a Schweizer airplane equipped to measure electric field and other meteorological parameters flew over Kennedy Space Center (KSC) in a program to study clouds defined in the existing launch restriction criteria. A case study is presented of a single flight over KSC on November 4, 1988. This flight was chosen for two reasons: (1) the clouds were weakly electrified, and no lightning was reported during the flight; and (2) electric field mills in the surface array at KSC indicated field strengths greater than 3 kV/m, yet the aircraft flying directly over them at an altitude of 3.4 km above sea level measured field strengths of less than 1.6 kV/m. A weather summary, sounding description, record of cloud types, and an account of electric field measurements are included.

  16. Spatial variation of sea surface temperature and flux-related parameters measured from aircraft in the JASIN experiment

    NASA Technical Reports Server (NTRS)

    Liu, W. T.; Katsaros, K. B.

    1984-01-01

    Spatial variation of some parameters measured on two aircraft flying 100-km box and 200-km triangular patterns at low levels in the atmospheric boundary layer during the Joint Air Sea Interaction Experiment in the North Atlantic was studied. The variation should be representative of summer conditions in mid-latitude oceans. The variance density of remotely sensed sea surface temperature, corrected for sky reflection, is found to depend on the one-dimensional wave number raised to the power of approximately -5/3. Nonuniform clouds add low-frequency variance to observations of a downward looking radiometer and result in steeper slope of the spectra of uncorrected sea surface temperature. Turbulent fluxes of momentum, sensible heat, and moisture were determined with the bulk formulae from the parameters (wind speed, temperature, specific humidity, and sea surface temperature) measured from the aircraft. The averages of these fluxes over each flight leg were compared with the fluxes determined from the parameters averaged over the same leg. The difference is negligible, showing that spatially averaged observations, such as those from spaceborne sensors, can be used in the bulk formulae to evaluate the fluxes.

  17. Measurement of OH, H2SO4, MSA, DMSO, DMSO2 on the NASA P-3B Aircraft

    NASA Technical Reports Server (NTRS)

    Eisele, F. L.

    1998-01-01

    This project involves the deployment of a variety of unique aircraft measurements for the PEM-Tropics program. These measurements were all to be accomplished on a near simultaneous basis using a two channel selected ion chemical ionization mass spectrometer instrument. The first year of this project consisted of four components; improve and perform additional testing of the OH, H2SO4, and MSA instrument which had only flown on one previous mission (ACE-I); develop and test the vacuum and electronic hardware and software which would allow two independent mass spectrometer systems to be operated from a single instrument (one vacuum/pumping system); construct an aircraft compatible DMSO/DMS02 ion source and calibration system; and operate the above system on the NASA P-3B during PEM-Tropics. The first two of the components were to be accomplished at NCAR. The third component was to be completed at Georgia Tech and the fourth was to be conducted by researchers from both institutions on the NASA P-3B.

  18. Drop size distributions and related properties of fog for five locations measured from aircraft

    NASA Technical Reports Server (NTRS)

    Zak, J. Allen

    1994-01-01

    Fog drop size distributions were collected from aircraft as part of the Synthetic Vision Technology Demonstration Program. Three west coast marine advection fogs, one frontal fog, and a radiation fog were sampled from the top of the cloud to the bottom as the aircraft descended on a 3-degree glideslope. Drop size versus altitude versus concentration are shown in three dimensional plots for each 10-meter altitude interval from 1-minute samples. Also shown are median volume radius and liquid water content. Advection fogs contained the largest drops with median volume radius of 5-8 micrometers, although the drop sizes in the radiation fog were also large just above the runway surface. Liquid water content increased with height, and the total number of drops generally increased with time. Multimodal variations in number density and particle size were noted in most samples where there was a peak concentration of small drops (2-5 micrometers) at low altitudes, midaltitude peak of drops 5-11 micrometers, and high-altitude peak of the larger drops (11-15 micrometers and above). These observations are compared with others and corroborate previous results in fog gross properties, although there is considerable variation with time and altitude even in the same type of fog.

  19. Elevating your elevator talk

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An important and often overlooked item that every early career researcher needs to do is compose an elevator talk. The elevator talk, named because the talk should not last longer than an average elevator ride (30 to 60 seconds), is an effective method to present your research and yourself in a clea...

  20. Apparatus and method for direct measurement of coal ash sintering and fusion properties at elevated temperatures and pressures

    DOEpatents

    Khan, M. Rashid

    1990-01-01

    A high-pressure microdilatometer is provided for measuring the sintering and fusion properties of various coal ashes under the influence of elevated pressures and temperatures in various atmospheres. Electrical resistivity measurements across a sample of coal ash provide a measurement of the onset of the sintering and fusion of the ash particulates while the contraction of the sample during sintering is measured with a linear variable displacement transducer for detecting the initiation of sintering. These measurements of sintering in coal ash at different pressures provide a mechanism by which deleterious problems due to the sintering and fusion of ash in various combustion systems can be minimized or obviated.

  1. High-precision measurements of wetland sediment elevation. I. Recent improvements to the sedimentation--erosion table

    USGS Publications Warehouse

    Cahoon, D.R.; Lynch, J.C.; Hensel, P.; Boumans, R.; Perez, B.C.; Segura, B.; Day, J.W.

    2002-01-01

    The sedimentation-erosion table (SET) developed by Boumans and Day (1993) is herein renamed the surface elevation table (SET) to better reflect the conceptual view of the processes being measured. The SET was designed for making high-resolution measurements of small-scale changes in elevation of loose, unconsolidated sediments in shallow water and mudflat habitats. The SET has undergone three major improvements to increase precision and so that it can be used to measure sediment elevation in vegetated wetlands as well as shallow water habitats. The remote-release 'sliding plate' mechanism has been replaced with a single plate, collars (first 2.5 cm then 7.5 cm in length) have been attached to the plate to reduce play in the placement of the measuring pins, and the brass measuring pins have been replaced with fiberglass pins to reduce bending and consequent loss of precision. Under ideal laboratory conditions, the 95% confidence limit for individual pin measurements averaged about A? 1.4 mm (range A? 0.7 to A? 1.9 mm). These modifications have resulted in a reduction of error by about 50%.

  2. Turbulence as observed by concurrent measurements made at NSSL using weather radar, Doppler radar, Doppler lidar and aircraft

    NASA Technical Reports Server (NTRS)

    Lee, Jean T.

    1987-01-01

    As air traffic increases and aircraft capability increases in range and operating altitude, the exposure to weather hazards increases. Turbulence and wind shears are two of the most important of these hazards that must be taken into account if safe flight operations are to be accomplished. Beginning in the early 1960's, Project Rough Rider began thunderstorm investigations. Past and present efforts at the National Severe Storm Laboratory (NSSL) to measure these flight safety hazards and to describe the use of Doppler radar to detect and qualify these hazards are summarized. In particular, the evolution of the Doppler-measured radial velocity spectrum width and its applicability to the problem of safe flight is presented.

  3. Aircraft Engine On-Line Diagnostics Through Dual-Channel Sensor Measurements: Development of a Baseline System

    NASA Technical Reports Server (NTRS)

    Kobayashi, Takahisa; Simon, Donald L.

    2008-01-01

    In this paper, a baseline system which utilizes dual-channel sensor measurements for aircraft engine on-line diagnostics is developed. This system is composed of a linear on-board engine model (LOBEM) and fault detection and isolation (FDI) logic. The LOBEM provides the analytical third channel against which the dual-channel measurements are compared. When the discrepancy among the triplex channels exceeds a tolerance level, the FDI logic determines the cause of the discrepancy. Through this approach, the baseline system achieves the following objectives: (1) anomaly detection, (2) component fault detection, and (3) sensor fault detection and isolation. The performance of the baseline system is evaluated in a simulation environment using faults in sensors and components.

  4. Comparison of Measured and Block Structured Simulations for the F-16XL Aircraft

    NASA Technical Reports Server (NTRS)

    Boelens, O. J.; Badcock, K. J.; Elmilgui, A.; Abdol-Hamid, K. S.; Massey, S. J.

    2008-01-01

    This article presents a comparison of the predictions of three RANS codes for flight conditions of the F-16XL aircraft which feature vortical flow. The three codes, ENSOLV, PMB and PAB3D, solve on structured multi-block grids. Flight data for comparison was available in the form of surface pressures, skin friction, boundary layer data and photographs of tufts. The three codes provided predictions which were consistent with expectations based on the turbulence modelling used, which was k- , k- with vortex corrections and an Algebraic Stress Model. The agreement with flight data was good, with the exception of the outer wing primary vortex strength. The confidence in the application of the CFD codes to complex fighter configurations increased significantly through this study.

  5. Aircraft measurements of black carbon vertical profiles show upper tropospheric variability and stability

    NASA Astrophysics Data System (ADS)

    Schwarz, Joshua P.; Weinzierl, Bernadett; Samset, Bjørn H.; Dollner, Maximilian; Heimerl, Katharina; Markovic, Milos Z.; Perring, Anne E.; Ziemba, Luke

    2017-01-01

    We present new data sets of black carbon (BC) aerosol mass mixing ratio (MMR) obtained from aircraft missions over North America, Europe, the Arctic, and the outflow region of Saharan Africa before and after trans-Atlantic transport. The data, collected from 2011 to 2013 with single-particle soot photometers, provide new insight into the variability and distribution of BC over global scales and refine understanding of AeroCom global model ensemble performance. The results indicate extensive global-scale longitudinal mixing of BC above altitude pressures as low as 400 hPa. They also constrain the absolute and temporal variability of upper tropospheric BC MMR and point to opportunities for new tests of global aerosol models in the upper troposphere. A comparison to the AeroCom Phase II results generally reinforces previous estimates of the ensemble performance, except that it also strengthens confidence that the ensemble actually is biased high in the Arctic in all seasons.

  6. Millimeter-wave radiometric measurements of a treeline and building for aircraft obstacle avoidance

    NASA Astrophysics Data System (ADS)

    Wikner, David A.

    2003-08-01

    Passive millimeter-wave (MMW) imagers have the potential to be used on low-flying aircraft for terrain-following / terrain-avoidance during low-visibility conditions. This potential exists because of the inherent nature of MMW radiation that allows it to penetrate many visible and IR obscurants such as fog, clouds, and smoke. The phenomenology associated with this application, however, has not been fully explored. Specifically, the radiometric signatures of the various obstacles that might be encountered during a low-altitude flight need to be thoroughly understood. The work described in this paper explores the 93-GHz passive signature of a deciduous treeline and a concrete/glass building. The data were taken from the roof of a 4-story building to simulate the view of a low-flying aircraft. The data were collected over many months with an ARL-built Stokes-vector radiometer. This radiometer is a single-beam system that raster scans over a scene to collect a calibrated 93-GHz image. The data show the effects of weather and tree lifecycle on the 93-GHz brightness temperature contrast between the horizon sky and the obstacles. For the case of trees, it is shown that the horizon sky brightness temperature is greater than that of the trees when the leaves are on because of the reflective properties of the leaves. This made the trees quite detectable to our system during the late spring, summer, and early fall. Concrete buildings are inherently low-contrast obstacles because their vertical nature reflects the horizon behind the sensor and can easily mimic the forward horizon sky. Solar loading can have a large effect on building signatures.

  7. A robust threshold retracking algorithm for measuring ice-sheet surface elevation change from satellite radar altimeters

    SciTech Connect

    Davis, C.H.

    1997-07-01

    A threshold retracking algorithm for processing ice-sheet altimeter data is presented. The primary purpose for developing this algorithm is detection of ice-sheet elevation change, where it is critical that a retracking algorithm produce repeatable elevations. The more consistent an algorithm is in selecting the retracking point the less likely that errors and/or biases will be introduced by the retracking scheme in the elevation-change measurement. The authors performed extensive comparisons between the threshold algorithm and two other widely used ice-sheet retracking algorithms on Geosat datasets comprised of over 60,000 crossover points. The results show that the threshold retracking algorithm, with a 10% threshold level, produces ice-sheet surface elevations that are more repeatable than the elevations derived from the other retracking algorithms. For this reason, the threshold retracking algorithm has been adopted by NASA/GSFC as an alternative to their existing algorithm for production of ice-sheet altimeter datasets under the NASA Pathfinder program. The threshold algorithm will be used to re-process existing ice-sheet altimeter datasets and to process the datasets from future altimeter missions.

  8. Task-specific tailored multiple-reflection mirror systems for sensitivity enhancement of spectroscopic measurements: application for aircraft engine exhaust emission measurements with FT-IR spectro

    NASA Astrophysics Data System (ADS)

    Brockmann, Klaus; Kurtenbach, Ralf; Kriesche, Volker; Wiesen, Peter; Heland, Joerg; Schaefer, Klaus

    1999-09-01

    Multi-path reflection mirror systems in White- or Herriott- type configuration have been widely used to enhance the absorption path-length and thus the sensitivity of laboratory spectroscopic systems, e.g. for smog chamber studies and molecular spectroscopy. Field studies, for instance using mobile tunable diode laser spectroscopy have widened the range of applications of these mirror systems for specific measurement tasks. In this paper a special designed White-type system mounted in two racks with 5 m base-length and adjustable optical path-length up to 74 passes is described. This system has been tested and successfully used to enhance the sensitivity of non-intrusive FT-IR measurements of aircraft engine exhaust emissions in the harsh environment of an engine test bed. The open cell around the engine plume including the transfer optics for the adaption of the spectrometers in a separate room allowed manual switching between passive FT-IR emission measurements, FT-IR absorption measurements with the cell, and, by covering the infrared source (globar) with a shutter, multi-path FT-IR emission measurements. Tests prior to the aircraft engine measurements were made to investigate the influence of different path- lengths, the position of the plume in the White cell, soot in the exhaust gas, and vibrations of the mirrors. The FT-IR spectra from all three measurement modes using the White cell during the engine measurements were found to be of good quality and the results of the analyses were comparable to the results from intrusive measurement systems.

  9. Cable Tensiometer for Aircraft

    NASA Technical Reports Server (NTRS)

    Nunnelee, Mark (Inventor)

    2008-01-01

    The invention is a cable tensiometer that can be used on aircraft for real-time, in-flight cable tension measurements. The invention can be used on any aircraft cables with high precision. The invention is extremely light-weight, hangs on the cable being tested and uses a dual bending beam design with a high mill-volt output to determine tension.

  10. The atmospheric effects of stratospheric aircraft. Report of the 1992 Models and Measurements Workshop. Volume 2: Comparisons with global atmospheric measurements

    NASA Technical Reports Server (NTRS)

    Prather, Michael J. (Editor); Remsberg, Ellis E. (Editor)

    1993-01-01

    This Workshop on Stratospheric Models and Measurements (M&M) marks a significant expansion in the history of model intercomparisons. It provides a foundation for establishing the credibility of stratospheric models used in environmental assessments of chlorofluorocarbons, aircraft emissions, and climate-chemistry interactions. The core of the M&M comparisons involves the selection of observations of the current stratosphere (i.e., within the last 15 years): these data are believed to be accurate and representative of certain aspects of stratospheric chemistry and dynamics that the models should be able to simulate.

  11. Noise measurements for a twin-engine commercial jet aircraft during 3 deg approaches and level flyovers

    NASA Technical Reports Server (NTRS)

    Hastings, E. C., Jr.; Shanks, R. E.; Mueller, A. W.

    1976-01-01

    Noise measurements have been made with a twin-engine commercial jet aircraft making 3 deg approaches and level flyovers. The flight-test data showed that, in the standard 3 deg approach configuration with 40 deg flaps, effective perceived noise level (EPNL) had a value of 109.5 effective perceived noise decibels (EPNdB). This result was in agreement with unpublished data obtained with the same type of aircraft during noise certification tests; the 3 deg approaches made with 30 deg flaps and slightly reduced thrust reduced the EPNL value by 1 EPNdB. Extended center-line noise determined during the 3 deg approaches with 40 deg flaps showed that the maximum reference A-weighted sound pressure level (LA,max)ref varied from 100.0 A-weighted decibels 2.01 km (108 n. mi.) from the threshold to 87.4 db(A) at 6.12 km (3.30 n. mi.) from the threshold. These test values were about 3 db(A) higher than estimates used for comparison. The test data along the extended center line during approaches with 30 deg flaps were 1 db(A) lower than those for approaches with 40 deg flaps. Flight-test data correlating (LA,max)ref with thrust at altitudes of 122 m (400 ft) and 610 m (2000 ft) were in agreement with reference data used for comparison.

  12. Comparison of improved Aura Tropospheric Emission Spectrometer (TES) CO2 with HIPPO and SGP aircraft profile measurements

    SciTech Connect

    Kulawik, S. S.; Worden, J. R.; Wofsy, S. C.; Biraud, S. C.; Nassar, R.; Jones, D. B. A.; Olsen, E. T.; Osterman, and the TES and HIPPO teams, G. B.

    2012-01-01

    Comparisons are made between mid-tropospheric Tropospheric Emission Spectrometer (TES) carbon dioxide (CO{sub 2}) satellite measurements and ocean profiles from three Hiaper Pole-to-Pole Observations (HIPPO) campaigns and land aircraft profiles from the United States Southern Great Plains (SGP) Atmospheric Radiation Measurement (ARM) site over a 4-yr period. These comparisons are used to characterize the bias in the TES CO{sub 2} estimates and to assess whether calculated and actual uncertainties and sensitivities are consistent. The HIPPO dataset is one of the few datasets spanning the altitude range where TES CO{sub 2} estimates are sensitive, which is especially important for characterization of biases. We find that TES CO{sub 2} estimates capture the seasonal and latitudinal gradients observed by HIPPO CO{sub 2} measurements; actual errors range from 0.8–1.2 ppm, depending on the campaign, and are approximately 1.4 times larger than the predicted errors. The bias of TES versus HIPPO is within 0.85 ppm for each of the 3 campaigns; however several of the sub-tropical TES CO{sub 2} estimates are lower than expected based on the calculated errors. Comparisons of aircraft flask profiles, which are measured from the surface to 5 km, to TES CO{sub 2} at the SGP ARM site show good agreement with an overall bias of 0.1 ppm and rms of 1.0 ppm. We also find that the predicted sensitivity of the TES CO{sub 2} estimates is too high, which results from using a multi-step retrieval for CO{sub 2} and temperature. We find that the averaging kernel in the TES product corrected by a pressure-dependent factor accurately reflects the sensitivity of the TES CO{sub 2} product.

  13. Corrigendum to "Measuring the 3-D wind vector with a weight-shiftmicrolight aircraft" published in Atmos. Meas. Tech., 4, 1421-1444, 2011

    NASA Astrophysics Data System (ADS)

    Metzger, S.; Junkermann, W.; Butterbach-Bahl, K.; Schmid, H. P.; Foken, T.

    2011-07-01

    This study investigates whether the 3-D wind vector can be measured reliably from a highly transportable and low-cost weight-shift microlight aircraft. We draw up a transferable procedure to accommodate flow distortion originating from the aircraft body and -wing. This procedure consists of the analysis of aircraft dynamics and seven successive calibration steps. For our aircraft the horizontal wind components receive their greatest single amendment (14 %, relative to the initial uncertainty) from the correction of flow distortion magnitude in the dynamic pressure computation. Conversely the vertical wind component is most of all improved (31 %) by subsequent steps considering the 3-D flow distortion distribution in the flow angle computations. Therein the influences of the aircraft's trim (53 %), as well as changes in the aircraft lift (16 %) are considered by using the measured lift coefficient as explanatory variable. Three independent lines of analysis are used to evaluate the quality of the wind measurement: (a) A wind tunnel study in combination with the propagation of sensor uncertainties defines the systems input uncertainty to ≈0.6 m s-1 at the extremes of a 95 % confidence interval. (b) During severe vertical flight manoeuvres the deviation range of the vertical wind component does not exceed 0.3 m s-1. (c) The comparison with ground based wind measurements yields an overall operational uncertainty (root mean square error) of ≈0.4 m s-1 for the horizontal and ≈0.3 m s-1 for the vertical wind components. No conclusive dependence of the uncertainty on the wind magnitude (<8 m s-1) or true airspeed (ranging from 23-30 m s-1) is found. Hence our analysis provides the necessary basis to study the wind measurement precision and spectral quality, which is prerequisite for reliable Eddy-Covariance flux measurements.

  14. A Comparison of Measurements from ATMOS and Instruments Aboard the ER-2 Aircraft: Tracers of Atmospheric Transport and Halogenated Gases

    NASA Technical Reports Server (NTRS)

    Chang, A. Y.; Salawitch, R. J.; Michelsen, H. A.; Gunson, M. R.; Abrams, M. C.; Zander, R.; Rinsland, C. P.; Loewenstein, M.; Podolske, J. R.; Proffitt, M. H.; Margitan, J. J.; Fahey, D. W.; Gao, R.-S.; Kelly, K. K.; Elkins, J. W.; Webster, C. R.; May, R. D.; Chan, K. R.; Abbas, M. M.; Goldman, A.

    1996-01-01

    We compare volume mixing ratio profiles of N2O, O3, NO(y), H2O, CH4, and CO in the mid-latitude lower stratosphere measured by the ATMOS Fourier transform spectrometer on the ATLAS-3 Space Shuttle Mission with in situ measurements acquired from the NASA ER-2 aircraft during Nov 1994. ATMOS and ER-2 observations of (N2O) show good agreement, as do measured correlations of (O3), (NO(y)), (H2O), and (CH4) with (N2O). Thus a consistent measure of the hydrogen (H2O, CH4) content of the lower stratosphere is provided by the two platforms. The similarity of (NO(y)) determined by detection of individual species by ATMOS and the total (NOy) measurement on the ER-2 provides strong corroboration for the accuracy of both techniques. A 25% discrepancy in lower stratospheric (CO) observed by ATMOS and the ER-2 remains unexplained. Otherwise, the agreement for measurements of long-lived tracers demonstrates the ability to combine ATMOS data with in situ observations for quantifying atmospheric transport.

  15. A Comparison of Measurements from ATMOS and Instruments Aboard the ER-2 Aircraft: Tracers of Atmospheric Transport

    NASA Technical Reports Server (NTRS)

    Chang, A. Y.; Salawitch, R. J.; Michelsen, H. A.; Gunson, M. R.; Abrams, M. C.; Zander, R.; Rinsland, C. P.; Loewenstein, M.; Podolske, J. R.; Proffitt, M. H.; Margitan, J. J.; Fahey, D. W.; Gao, R.-S.; Kelly, K. K.; Elkins, J. W.; Webster, C. R.; May, R. D.; Chan, K. R.; Abbas, M. M.; Goldman, A.

    1996-01-01

    We compare volume mixing ratio profiles of N2O, O3, NO(y) H2O, CH4, and CO in the mid-latitude lower stratosphere measured by the ATMOS Fourier transform spectrometer on the ATLAS-3 Space Shuttle Mission with in situ measurements acquired from the NASA ER-2 aircraft during Nov 1994. ATMOS and ER-2 observations of [N2O] show good agreement, as do measured correlations of [O3], [NO(y)], [H2O], and [CH4] with [N2O]. Thus a consistent measure of the hydrogen (H2O, CH4) content of the lower stratosphere is provided by the two platforms. The similarity of [NO(y)] determined by detection of individual species by ATMOS and the total [NO(y)] measurement on the ER-2 provides strong corroboration for the accuracy of both techniques. A 25% discrepancy in lower stratospheric [CO] observed by ATMOS and the ER-2 remains unexplained. Otherwise, the agreement for measurements of long-lived tracers demonstrates the ability to combine ATMOS data with in situ observations for quantifying atmospheric transport.

  16. Optical depth distribution of optically thin clouds and surface elevation variability derived from CALIPSO lidar measurements (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Liu, Zhaoyan; Lin, Bing; Obland, Michael D.; Campbell, Joel

    2016-12-01

    Atmospheric carbon dioxide (CO2) is one of the major greenhouse gases in the Earth's climate system. The CO2 concentration in the atmosphere has been significantly increased over the last 150 years, due mainly to anthropogenic activities. Comprehensive measurements of global atmospheric CO2 distributions are urgently needed to develop a more complete understanding of CO2 sources and sinks. Because of the importance of the atmospheric CO2 measurements, satellite missions with passive sensors such as GOSAT and OCO-2 have been launched, and those with active sensors like Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) using an integrated path differential absorption (IPDA) lidar are being studied. The required accuracy and precision for the column-integrated CO2 mixing ratios (XCO2) is high, within 1.0 ppm or approximately 0.26%, which calls for unbiased CO2 measurements and accurate determinations of the path length. The presence of clouds and aerosols can make the measurement complicated, especially for passive instruments. The heterogeneity generated by the surface elevation changes within the field of view of the sensors and the grid boxes of averaged values of atmospheric CO2 would also cause significant uncertainties in XCO2 estimates if the path length is not accurately known. Thus, it is required to study the cloud and aerosol distributions as well as the surface elevation variability in assessing the performance of the CO2 measurements from both active and passive instruments. The CALIPSO lidar has acquired nearly 10 years of global measurement data. It provides a great opportunity to study the global distribution of clouds and aerosols as well as the statistics of the surface elevation variations. In this study we have analyzed multiple years of the CALIPSO Level 2 data to derive the global occurrence of aerosols and optically thin clouds. The results show that clear sky does not occur as frequently as expected. The global average

  17. Assesment of water elevation measurement quality from multi nadir altimetry missions over a 'small' river: the Garonne River case

    NASA Astrophysics Data System (ADS)

    Biancamaria, S.; Leleu, A. S.; Frappart, F.; Blumstein, D.; Marieu, V.; Sottolichio, A.; Valle-Levinson, A.

    2015-12-01

    For two decades, nadir altimetry mission measurements have been used to derive water elevation over rivers. It has been proven to be a powerful tool to estimate water elevation over big rivers (> 500 m), providing useful complementary data to in-situ gage networks. More recently, nadir altimetry data have been used successfully for some smaller rivers. It is therefore needed to assess potential errors from these measurements for these kind of river, using a well gaged basin.That's why we have investigated water elevations estimates from three altimetry missions (ENVISAT, Jason-2 and SARAL) over the Garonne River (South West of France). River width at studied river goes from 160 to 230 m.By comparison to nearby in-situ gages (IG), it has been shown that measurements from ENVISAT and Jason-2 virtual stations (VS) 100 km upstream of the estuary have errors between 20 to 70 cm for water anomaly, whereas most of the bias comes from river slope between IG and VS. 160 km upstream, the few usable ENVISAT VS have errors spanning from 80 to 160 cm. SARAL/AltiKa however, does not provide any water elevation information: there are rather no data in the record or measurements have huge bias with no correlation with water level variations. This is mainly due to high reliefs surrounding the river valley (up to 100 m difference between the valley and the top of the hills over few 10 km). SARAL/AlitKa, compared to previous instruments, has higher pulse bandwidth which results in a smaller range detection window of 30 m. It allows a higher vertical accuracy, but causes loss of data or to be 'locked' on the top of the hill even when it flies over the river valley, when there are important soil elevation variation over 'short' distance. This fact could also be observed for some Jason-2 and ENVISAT VS but to a much lower extent.Besides, water elevations time series has high frequencies due to local and upstream precipitation events. Therefore, it is more difficult to discriminate only

  18. Simultaneous measurements of ice sheet elevation change, accumulation, and firn compaction using Operation IceBridge data

    NASA Astrophysics Data System (ADS)

    Medley, Brooke; Ligtenberg, Stefan; van den Broeke, Michiel; Gogineni, Sivaprasad; Nowicki, Sophie

    2015-04-01

    Altimetric methods for determination of ice sheet mass balance are extremely valuable as they typically measure large regions of the ice sheet, from basin- to continental-scale. The measured volume change is converted to mass change if the density of the lost material is known. The complication lies in the fact that the observed elevation change consists of two components of differing densities: firn and ice. Annual fluctuations in snow accumulation and firn compaction cause the firn column to vary in thickness, which is often a large component of the total elevation change in the interior since the density of firn is less than that of ice. Further complication arises from the fact that fluctuations in the firn compaction rate do not result in mass change. Therefore, to properly determine mass change, the observed elevation change must be partitioned into accumulation, firn compaction, and ice components. Because altimetry studies are often large in scale, models are used to account for the firn processes, which are coarse in resolution (~10s kilometers) relative to the observed elevation changes (sub-kilometer). Here, we take advantage of a unique opportunity to simultaneously measure surface elevation change, snow accumulation, and firn compaction over the Thwaites catchment in West Antarctica using two Operation IceBridge (OIB) sensors. The firn processes are observed using the Center for Remote Sensing of Ice Sheets (CReSIS) snow radar, and elevation changes are measured using the Airborne Topographic Mapper. Coincident observations such as the aforementioned allow us to not only accurately evaluate mass change over short distances, but also determine the importance of accounting for small-scale variations in firn processes in large-scale (basin-wide to continental) assessments of mass balance. Our results indicate that accumulation rates vary by more than 10% and compaction rates vary by more than 10 cm/yr over distances as little as 5 km in this region. Thus

  19. Infrared aircraft measurements of stratospheric composition over Antarctica during September 1987

    NASA Technical Reports Server (NTRS)

    Toon, G. C.; Farmer, C. B.; Lowes, L. L.; Schaper, P. W.; Blavier, J.-F.

    1989-01-01

    The Jet Propulsion Laboratory Mark IV interferometer recorded high-resolution, infrared solar spectra from the NASA DC-8 aircraft during flights over Antarctica in September 1987. The atmospheric absorption features in these spectra have been analyzed to determine the burdens of O3, NO, NO2, HNO3, ClNO3, HCl, HF, CO2, CH4, N2O, HCN, CO, H2O, CFCl3, and CF2Cl2. The results show a 'collar' of high HNO3 and ClNO3 surrounding a 'core' in which the burdens of these and of HCl and NO2 are very low. Clear increases in the burdens of HF and HNO3 were observed during the course of September in the vortex core. HCl and NO2 exhibited smaller, less significant increases. The burdens of the tropospheric source gases, N2O, CH4, HCN, CFCl3, CF2Cl2, CO, and H2O, were observed to be much smaller over Antarctica than at midlatitudes. This, together with the fact that HF over Antarctica was more than double its midlatidue value, suggests that downwelling had occurred.

  20. Nighttime aircraft measurements of power plant plumes in the Southeast U.S

    NASA Astrophysics Data System (ADS)

    Brown, S. S.; Womack, R. W.; Edwards, P. M.; Dube, W. P.; Min, K.; Ryerson, T. B.; Peischl, J.; Pollack, I. B.; Roberts, J. M.; Veres, P. R.; Lee, B.; Lopez-Hilfiker, F.; Thornton, J. A.; Neuman, J. A.; Nowak, J. B.; Graus, M.; Warneke, C.; De Gouw, J. A.; Brock, C. A.; Trainer, M.; Parrish, D. D.

    2013-12-01

    Coal fired electric power plants are responsible for a large but declining fraction of U.S. NO¬x emissions. The influence of these point source emissions on ozone photochemistry has been well documented. Less well understood, however, is their influence on nighttime chemistry, due in part to the difficulty of sampling such plumes at night, when they are emitted into the residual boundary layer and remain decoupled from the surface. Nighttime chemistry in such plumes influences rates of biogenic VOC oxidation by the nitrate radical (NO3), halogen activation through the heterogeneous uptake of N2O5 to form ClNO2, and the overnight removal of primary NO¬x emissions via conversion to soluble nitrate. During the recent SENEX campaign, night flights of the NOAA P-3 aircraft sampled several different power plant plumes across the southeastern U.S., including the E.C. Gaston plant in Alabama, the New Madrid plant in Missouri, and the White Bluff plant in Arkansas. This presentation will analyze these nighttime power plant plume intercepts in terms of mixing (i.e., plume dispersion) and nighttime chemistry. Results will be interpreted in the context of the overall decline in emissions from such sources across the eastern United States, as well as the impact of concentrated anthropogenic emission sources in a region with large summertime biogenic emissions.

  1. Measured Changes in C-Band Radar Reflectivity of Clear Air Caused by Aircraft Wake Vortices

    NASA Technical Reports Server (NTRS)

    Mackenzie, Anne I.

    1997-01-01

    Wake vortices from a C-130 airplane were observed at the NASA Wallops Flight Facility with a ground-based, monostatic C-band radar and an antenna-mounted boresight video camera. The airplane wake was viewed from a distance of approximately 1 km, and radar scanning was adjusted to cross a pair of marker smoke trails generated by the C-130. For each airplane pass, changes in radar reflectivity were calculated by subtracting the signal magnitudes during an initial clutter scan from the signal magnitudes during vortex-plus-clutter scans. The results showed both increases and decreases in reflectivity on and near the smoke trails in a characteristic sinusoidal pattern of heightened reflectivity in the center and lessened reflectivity at the sides. Reflectivity changes in either direction varied from -131 to -102 dBm(exp -1); the vortex-plus-clutter to noise ratio varied from 20 to 41 dB. The radar recordings lasted 2.5 min each; evidence of wake vortices was found for up to 2 min after the passage of the airplane. Ground and aircraft clutter were eliminated as possible sources of the disturbance by noting the occurrence of vortex signatures at different positions relative to the ground and the airplane. This work supports the feasibility of vortex detection by radar, and it is recommended that future radar vortex detection be done with Doppler systems.

  2. Description and interpretation of aircraft lightning attachment electric and magnetic field measurements and video observation

    NASA Technical Reports Server (NTRS)

    Moreau, J. P.; Larigaldie, S.

    1991-01-01

    In 1988, ONERA carried out a complete airborne lightning characterization program. Among other features, the program has provided a significant amount of data from analog records of electric and magnetic field sensors to give a description of all stages of the lightning process. The initiation phase has a description of all stages of the lightning process. The initiation phase has been described in the past, so the present objective is to give a description of the other stages of the discharge, based on the observation of analog electromagnetic waveforms and of fast video (200 f/s) image processed pictures. During lightning attachment, the aircraft remains electrically connected to the lightning channel where a large variety of physical processes occur. These physical processes include recoil streamers, return strokes, and even other initiation processes of secondary discharges. Typical records of analog electromagnetic field along with relative luminosity variation of the channel, which shows that there is no extinction of the continuous current throughout the discharge process. A computation of current and potential waveforms using the transmission line formalism is presented and gives satisfactory results for the representation of two of the typical waveforms observed in the recoil streamer processes.

  3. Physical Processes Governing Atmospheric Trace Constituents Measured from Aircraft in Pem-Tropics

    NASA Technical Reports Server (NTRS)

    Newell, Reginald E.

    1999-01-01

    The MIT group participated in seven publications in the 1999 issues of JGR with sections devoted in PEM-Tropics A, and had two papers which may be considered offshoots of these studies combined with commercial aircraft trace constituents data, one in Nature and one in EOS. In the meteorological overview we contributed a set of 1000 hPa divergent wind maps which we calculated from ECMWF data, meridional wind cross-sections, velocity potential and divergent wind maps, maps of stream function and rotational wind components, and vertical velocity profiles computed from mass balance, these all constituting part of the overall climatology. We also contributed material for the "stalactite" case observed from the DC-8 on September 3, 1996. This included a map of potential vorticity on 350 K, a cross-section of lidaro O3 a cross-section of potential vorticity along 140 deg W, and a map of specific humidity showing extreme dryness accompanying the high potential vorticity values and the high ozone values, all suggesting subsidence from the local stratosphere. In the paper on chemical characteristics we contributed 12 hour values of the 1000 hPa divergent wind component for the full period of PEM Tropics A; these were used by David Westberg to establish the air mass boundaries and in turn used by Gerry Gregory to set up a table of quantitative values of trace constituents and their ratios both sides of the boundaries.

  4. Aircraft measurements of the mean and turbulent structure of marine stratocumulus clouds during FIRE

    NASA Technical Reports Server (NTRS)

    Albrecht, Bruce A.; Kloesel, Kevin A.; Moyer, Kerry A.; Nucciarone, Jefferey J.; Young, George

    1990-01-01

    The mean and turbulent structure of marine stratocumulus clouds is defined from data that were collected from 10 flights made with the National Center for Atmospheric Research (NCAR) Electra during the First ISCCP Regional Experiment (FIRE). The number of cases sampled is sufficiently large that researchers can compare the boundary layer structure obtained (1) for solid and broken cloud conditions, (2) for light and strong surface wind conditions, (3) for different sea-surface temperatures, and (4) on day and night flights. Researchers will describe the cloud and synoptic conditions present at the time of the Electra flights and show how those flights were coordinated with the operations of other aircraft and with satellite overpasses. Mean thermodynamic and wind profiles and the heat, moisture, and momentum fluxes obtained from data collected during these flights will be compared. Variations in the cloud-top structure will be quantified using LIDAR data collected during several of the Electra flights. The spatial structure of cloud-top height and the cloud-base height will be compared with the turbulent structure in the boundary layer as defined by spectra and cospectra of the wind, temperature, and moisture.

  5. Unmanned Aircraft in the Measurement of Carbon Dioxide in Buoyant Plumes

    NASA Astrophysics Data System (ADS)

    Jacob, J.

    2015-12-01

    Carbon sequestration, the storage of carbon dioxide gas underground, has the potential to reduce global warming by removing a greenhouse gas from the atmosphere. These storage sites, however, must first be monitored to detect if carbon dioxide is leaking back out to the atmosphere. As an alternative to traditional large ground-based sensor networks to monitor CO2 levels for leaks, unmanned aircraft offer the potential to perform in-situ atmospheric leak detection over large areas for a fraction of the cost. This project developed a proof-of-concept sensor system to map relative carbon dioxide levels to detect potential leaks. Ground tests were performed to verify and calibrate the system including wind tunnel tests to determine the optimal configuration of the system to account for dynamic calibration models required to determine accurate location of gas concentration in (x,y,z,t). Field tests were then conducted over a controlled release of CO2 as well as over controlled rangeland fires which released carbon dioxide over a large area. 3D maps of carbon dioxide were developed from the system telemetry that clearly illustrated increased CO2 levels from the fires. Results are compared with dynamic atmospheric models of gas dispersion within plumes.

  6. Constraining the 2012-2014 growing season Alaskan methane budget using CARVE aircraft measurements

    NASA Astrophysics Data System (ADS)

    Hartery, S.; Chang, R. Y. W.; Commane, R.; Lindaas, J.; Miller, S. M.; Wofsy, S. C.; Karion, A.; Sweeney, C.; Miller, C. E.; Dinardo, S. J.; Steiner, N.; McDonald, K. C.; Watts, J. D.; Zona, D.; Oechel, W. C.; Kimball, J. S.; Henderson, J.; Mountain, M. E.

    2015-12-01

    Soil in northen latitudes contains rich carbon stores which have been historically preserved via permafrost within the soil bed; however, recent surface warming in these regions is allowing deeper soil layers to thaw, influencing the net carbon exchange from these areas. Due to the extreme nature of its climate, these eco-regions remain poorly understood by most global models. In this study we analyze methane fluxes from Alaska using in situ aircraft observations from the 2012-2014 Carbon in Arctic Reservoir Vulnerability Experiment (CARVE). These observations are coupled with an atmospheric particle transport model which quantitatively links surface emissions to atmospheric observations to make regional methane emission estimates. The results of this study are two-fold. First, the inter-annual variability of the methane emissions was found to be <1 Tg over the area of interest and is largely influenced by the length of time the deep soil remains unfrozen. Second, the resulting methane flux estimates and mean soil parameters were used to develop an empirical emissions model to help spatially and temporally constrain the methane exchange at the Alaskan soil surface. The empirical emissions model will provide a basis for exploring the sensitivity of methane emissions to subsurface soil temperature, soil moisture, organic carbon content, and other parameters commonly used in process-based models.

  7. Classification of Tropical Oceanic Precipitation using High Altitude Aircraft: Microwave and Electric Field Measurements

    NASA Technical Reports Server (NTRS)

    Hood, Robbie E.; Cecil, Daniel; LaFontaine, Frank J.; Blakeslee, Richard; Mach, Douglas; Heymsfield, Gerald; Marks, Frank, Jr.; Zipser, Edward

    2004-01-01

    During the 1998 and 2001 hurricane seasons of the western Atlantic Ocean and Gulf of Mexico, the Advanced Microwave Precipitation Radiometer (AMPR), the ER-2 Doppler (EDOP) radar, and the Lightning Instrument Package (LIP) were flown aboard the National Aeronautics and Space Administration ER-2 high altitude aircraft as part of the Third Convection and Moisture Experiment (CAMEX-3) and the Fourth Convection and Moisture Experiment (CAMEX-4). Several hurricanes, tropical storms, and other precipitation systems were sampled during these experiments. An oceanic rainfall screening technique has been developed using AMPR passive microwave observations of these systems collected at frequencies of 10.7, 19.35,37.1, and 85.5 GHz. This technique combines the information content of the four AMPR frequencies regarding the gross vertical structure of hydrometeors into an intuitive and easily executable precipitation mapping format. The results have been verified using vertical profiles of EDOP reflectivity and lower altitude horizontal reflectivity scans collected by the National Oceanic and Atmospheric Administration WP-3D Orion radar. Matching the rainfall classification results with coincident electric field information collected by the LIP readily identifies convective rain regions within the precipitation fields. This technique shows promise as a real-time research and analysis tool for monitoring vertical updraft strength and convective intensity from airborne platforms such as remotely operated or uninhabited aerial vehicles. The technique is analyzed and discussed for a wide variety of precipitation types using the 26 August 1998 observations of Hurricane Bonnie near landfall.

  8. Classification of Tropical Oceanic Precipitation using High-Altitude Aircraft Microwave and Electric Field Measurements

    NASA Technical Reports Server (NTRS)

    Hood, Robbie E.; Cecil, Daniel J.; LaFontaine, Frank J.; Blakeslee, Richard J.; Mach, Douglas m.; Heymsfield, Gerald M.; Marks, Frank D., Jr.; Zipser, Edward J.

    2004-01-01

    During the 1998 and 2001 hurricane seasons of the western Atlantic Ocean and Gulf of Mexico, the Advanced Microwave Precipitation Radiometer (AMPR), the ER-2 Doppler (EDOP) radar, and the Lightning Instrument Package (LIP) were flown aboard the NASA ER-2 high-altitude aircraft as part of the Third Convection and Moisture Experiment (CAMEX-3) and the Fourth Convection and Moisture Experiment (CAMEX-4). Several hurricanes, tropical storms, and other precipitation systems were sampled during these experiments. An oceanic rainfall screening technique has been developed using AMPR passive microwave observations of these systems collected at frequencies of 10.7, 19.35, 37.1, and 85.5 GHz. This technique combines the information content of the four AMPR frequencies regarding the gross vertical structure of hydrometeors into an intuitive and easily executable precipitation mapping format. The results have been verified using vertical profiles of EDOP reflectivity and lower-altitude horizontal reflectivity scans collected by the NOAA WP3D Orion radar. Matching the rainfall classification results with coincident electric field information collected by the LIP readily identifies convective rain regions within the precipitation fields. This technique shows promise as a real-time research and analysis tool for monitoring vertical updraft strength and convective intensity from airborne platforms such as remotely operated or uninhabited aerial vehicles. The technique is analyzed and discussed for a wide variety of precipitation types using the 26 August 1998 observations of Hurricane Bonnie near landfall.

  9. Performance Evaluation of Particle Sampling Probes for Emission Measurements of Aircraft Jet Engines

    NASA Technical Reports Server (NTRS)

    Lee, Poshin; Chen, Da-Ren; Sanders, Terry (Technical Monitor)

    2001-01-01

    Considerable attention has been recently received on the impact of aircraft-produced aerosols upon the global climate. Sampling particles directly from jet engines has been performed by different research groups in the U.S. and Europe. However, a large variation has been observed among published data on the conversion efficiency and emission indexes of jet engines. The variation results surely from the differences in test engine types, engine operation conditions, and environmental conditions. The other factor that could result in the observed variation is the performance of sampling probes used. Unfortunately, it is often neglected in the jet engine community. Particle losses during the sampling, transport, and dilution processes are often not discussed/considered in literatures. To address this issue, we evaluated the performance of one sampling probe by challenging it with monodisperse particles. A significant performance difference was observed on the sampling probe evaluated under different temperature conditions. Thermophoretic effect, nonisokinetic sampling and turbulence loss contribute to the loss of particles in sampling probes. The results of this study show that particle loss can be dramatic if the sampling probe is not well designed. Further, the result allows ones to recover the actual size distributions emitted from jet engines.

  10. A study of Asian dust plumes using satellite, surface, and aircraft measurements during the INTEX-B field experiment

    NASA Astrophysics Data System (ADS)

    Logan, Timothy; Xi, Baike; Dong, Xiquan; Obrecht, Rebecca; Li, Zhanqing; Cribb, Maureen

    2010-04-01

    Asian dust events occur frequently during the boreal spring season. Their optical properties have been analyzed by using a combination of source region (ground-based and satellite) and remote Pacific Ocean (aircraft) measurements during the Intercontinental Chemical Transport Experiment-Phase B (INTEX-B) field campaign which lasted from 7 April to 15 May 2006. A strong dust event originating from the Gobi Desert and passing over the Xianghe surface site on 17 April 2006 has been extensively analyzed. The surface averaged aerosol optical depth (AOD) values increased from 0.17 (clear sky) to 4.0 (strong dust), and the Angström exponent (α) dropped from 1.26 (clear sky) to below 0.1. Its total downwelling SW flux over the Xianghe site (thousands of kilometers away from the dust source region) is only 46% of the clear-sky value with almost no direct transmission and nearly double the diffuse SW clear-sky value. This event was also captured 6 days later by satellite observations as well as the UND/NASA DC-8 aircraft over the eastern Pacific Ocean. The DC-8 measurements in the remote Pacific region further classified the plumes into dust dominant, pollution dominant, and a mixture of dust and pollution events. HYSPLIT backward trajectories not only verified the origins of each case we selected but also showed (1) two possible origins for the dust: the Gobi and Taklimakan deserts; and (2) pollution: urban areas in eastern China, Japan, and other industrialized cities east of the two deserts. Based on the averaged satellite retrieved AOD data (0.5° × 0.5° grid box), declining AOD values with respect to longitude demonstrated the evolution of the transpacific transport pathway of Asian dust and pollution over the period of the field campaign.

  11. Improving and Assessing Aircraft-based Greenhouse Gas Emission Rate Measurements at Indianapolis as part of the INFLUX project.

    NASA Astrophysics Data System (ADS)

    Heimburger, A. M. F.; Shepson, P. B.; Stirm, B. H.; Susdorf, C.; Cambaliza, M. O. L.

    2015-12-01

    Since the Copenhagen accord in 2009, several countries have affirmed their commitment to reduce their greenhouse gas emissions. The United States and Canada committed to reduce their emissions by 17% below 2005 levels, by 2020, Europe by 14% and China by ~40%. To achieve such targets, coherent and effective strategies in mitigating atmospheric carbon emissions must be implemented in the next decades. Whether such goals are actually achieved, they require that reductions are "measurable", "reportable", and "verifiable". Management of greenhouse gas emissions must focus on urban environments since ~74% of CO2 emissions worldwide will be from cities, while measurement approaches are highly uncertain (~50% to >100%). The Indianapolis Flux Experiment (INFLUX) was established to develop, assess and improve top-down and bottom-up quantifications of urban greenhouse gas emissions. Based on an aircraft mass balance approach, we performed a series of experiments focused on the improvement of CO2, CH4 and CO emission rates quantification from Indianapolis, our final objective being to drastically improve the method overall uncertainty from the previous estimate of 50%. In November-December 2014, we conducted nine methodologically identical mass balance experiments in a short period of time (24 days, one downwind distance) for assumed constant total emission rate conditions, as a means to obtain an improved standard deviation of the mean determination. By averaging the individual emission rate determinations, we were able to obtain a method precision of 17% and 16% for CO2 and CO, respectively, at the 95%C.L. CH4 emission rates are highly variable day to day, leading to precision of 60%. Our results show that repetitive sampling can enable improvement in precision of the aircraft top-down methods through averaging.

  12. Removal of NOx and NOy in Asian outflow plumes: Aircraft measurements over the western Pacific in January 2002

    NASA Astrophysics Data System (ADS)

    Takegawa, N.; Kondo, Y.; Koike, M.; Chen, G.; Machida, T.; Watai, T.; Blake, D. R.; Streets, D. G.; Woo, J.-H.; Carmichael, G. R.; Kita, K.; Miyazaki, Y.; Shirai, T.; Liley, J. B.; Ogawa, T.

    2004-12-01

    The Pacific Exploration of Asian Continental Emission Phase A (PEACE-A) aircraft measurement campaign was conducted over the western Pacific in January 2002. Correlations of carbon monoxide (CO) with carbon dioxide (CO2) and back trajectories are used to identify plumes strongly affected by Asian continental emissions. ΔCO/ΔCO2 ratios (i.e., linear regression slopes of CO-CO2) in the plumes generally fall within the variability range of the CO/CO2 emission ratios estimated from an emission inventory for east Asia, demonstrating the consistency between the aircraft measurements and the emission characterization. Removal rates of reactive nitrogen (NOx and NOy) for the study region (altitude <4 km, 124°-140°E, 25°-45°N) are estimated using the correlation with CO2, the photochemical age of the plumes, and the NOx/CO2 emission ratio derived from the emission inventory. The plume age is estimated from the rates of hydrocarbon decay and hydroxyl radical (OH) concentration calculated using a constrained photochemical box model. The average lifetime of NOx is estimated to be 1.2 ± 0.4 days. Possible processes controlling the NOx lifetime are discussed in conjunction with results from earlier studies. The average lifetime of NOy is estimated to be 1.7 ± 0.5 days, which is comparable to the NOy lifetime of 1.7-1.8 days that has been previously reported for outflow from the United States. This similarity suggests the importance of chemical processing near the source regions in determining the NOy abundance.

  13. Combining Suborbital Measurements of Aerosol Optical Depth and Columnar Water Vapor for Satellite Sensor Validations in the CLAMS (Chesapeake Lighthouse and Aircraft Measurements for Satellites) Experiment, 2001

    NASA Astrophysics Data System (ADS)

    Redemann, J.; Schmid, B.; Livingston, J. M.; Russell, P. B.; Eilers, J. A.; Hobbs, P. V.; Kahn, R.; Smith, W. L.; Holben, B. N.; Rutledge, C. K.; Pitts, M. C.; Mishchenko, M. I.; Chowdhary, J.; Martins, J. V.; Plana-Fattori, A.; Charlock, T. P.

    2002-05-01

    As part of the Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS) experiment, July 10 - August 2, 2001, the 14-channel NASA Ames Airborne Tracking Sunphotometer (AATS-14) was operated successfully aboard the University of Washington Convair-580 during 10 research flights (~45 flight hours). The CLAMS campaign was a clear sky, shortwave (SW) closure campaign that entailed measurements from the Chesapeake Lighthouse research platform, several land sites, 6 research aircraft and the Terra satellite. CLAMS research goals included validation of satellite-based retrievals of aerosol properties, vertical profiles of radiative fluxes, temperature and water vapor. Suborbital measurements of aerosol optical depth (AOD) and columnar water vapor (CWV) were carried out at several AERONET sites and aboard five of the six airborne platforms using a variety of techniques. AATS-14 measures the direct solar beam transmission at 14 discrete wavelengths (354-1558 nm), yielding aerosol optical depth spectra and columnar water vapor. During coordinated flights of the UW Convair-580, AATS-14 measured full column aerosol optical depth spectra at exact Terra overpass time on at least 7 occasions. For five of these opportunities, AOD at 499nm was at or below 0.1. During Terra overpass on July 17, 2001, AATS-14 measured the largest AOD encountered during the entire experiment (~0.48 at 499nm), including a horizontal gradient in AOD of more than 0.1 over a distance of ~80 kilometers. We will illustrate how the spatially resolved measurements by AATS-14 and the temporally resolved AERONET measurements can be usefully combined for satellite validation purposes by constraining the small-scale aerosol variability off the US East coast. While the first part of this paper is focused on AATS-14 measurements, in the remainder of this paper we will show comparisons to other suborbital measurements obtained using (i) the AERONET sun/sky radiometer at the Chesapeake Lighthouse, (ii

  14. An experimental assessment of the use of ground-level microphones to measure the fly-over noise of jet-engined aircraft

    NASA Astrophysics Data System (ADS)

    Payne, R. C.

    1993-01-01

    During aircraft flight trials to measure the noise levels of six different military jet aircraft types in low altitude high speed operations, noise measurements were performed using microphones at ground level and at a height of 1.2 m. The program provided reliable data on the difference between sound pressure levels from the two microphone arrangements, for sound incident over a range of angles, from 0 deg (aircraft overhead) to approximately 80 deg. Substantial differences from ground level to 1.2 m were observed in measurements of maximum perceived noise level, effective perceived noise level and maximum A-weighted sound pressure level. For sound waves incident to the ground at angles less than approximately 60 deg from vertical, these differences were found to be independent of angle of incidence for all the six aircraft and all flight procedures. Within this range of sound incidence angles the ground plane arrangement produced data that closely approximated pressure doubled values. The conventional 1.2 m high microphone gave rise to noise levels approximately 4 dB lower. For sound incident at angles greater than 60 deg from vertical, the difference between noise levels measured using the two microphone configurations was found to depend on angle of incidence, reducing to zero at approximately 75 deg. When noise measurements are made using the ground plane arrangement, the effects of meteorological conditions must be considered in relation to sound incident at angles greater than approximately 60 deg.

  15. Aircraft Engine On-Line Diagnostics Through Dual-Channel Sensor Measurements: Development of an Enhanced System

    NASA Technical Reports Server (NTRS)

    Kobayashi, Takahisa; Simon, Donald L.

    2008-01-01

    In this paper, an enhanced on-line diagnostic system which utilizes dual-channel sensor measurements is developed for the aircraft engine application. The enhanced system is composed of a nonlinear on-board engine model (NOBEM), the hybrid Kalman filter (HKF) algorithm, and fault detection and isolation (FDI) logic. The NOBEM provides the analytical third channel against which the dual-channel measurements are compared. The NOBEM is further utilized as part of the HKF algorithm which estimates measured engine parameters. Engine parameters obtained from the dual-channel measurements, the NOBEM, and the HKF are compared against each other. When the discrepancy among the signals exceeds a tolerance level, the FDI logic determines the cause of discrepancy. Through this approach, the enhanced system achieves the following objectives: 1) anomaly detection, 2) component fault detection, and 3) sensor fault detection and isolation. The performance of the enhanced system is evaluated in a simulation environment using faults in sensors and components, and it is compared to an existing baseline system.

  16. Advances in Measuring Antarctic Sea-Ice Thickness and Ice-Sheet Elevations with ICESat Laser Altimetry

    NASA Technical Reports Server (NTRS)

    Zwally, H. Jay

    2004-01-01

    NASA's Ice, Cloud and Land Elevation Satellite (ICESat) has been measuring elevations of the Antarctic ice sheet and sea-ice freeboard elevations with unprecedented accuracy. Since February 20,2003, data has been acquired during three periods of laser operation varying from 36 to 54 days, which is less than the continuous operation of 3 to 5 years planned for the mission. The primary purpose of ICESat is to measure time-series of ice-sheet elevation changes for determination of the present-day mass balance of the ice sheets, study of associations between observed ice changes and polar climate, and estimation of the present and future contributions of the ice sheets to global sea level rise. ICESat data will continue to be acquired for approximately 33 days periods at 3 to 6 month intervals with the second of ICESat's three lasers, and eventually with the third laser. The laser footprints are about 70 m on the surface and are spaced at 172 m along-track. The on-board GPS receiver enables radial orbit determinations to an accuracy better than 5 cm. The orbital altitude is around 600 km at an inclination of 94 degrees with a 8-day repeat pattern for the calibration and validation period, followed by a 91 -day repeat period for the rest of the mission. The expected range precision of single footprint measurements was 10 cm, but the actual range precision of the data has been shown to be much better at 2 to 3 cm. The star-tracking attitude-determination system should enable footprints to be located to 6 m horizontally when attitude calibrations are completed. With the present attitude calibration, the elevation accuracy over the ice sheets ranges from about 30 cm over the low-slope areas to about 80 cm over areas with slopes of 1 to 2 degrees, which is much better than radar altimetry. After the first period of data collection, the spacecraft attitude was controlled to point the laser beam to within 50 m of reference surface tracks over the ice sheets. Detection of ice

  17. Tropospheric sampling with aircraft

    SciTech Connect

    Daum, P.H.; Springston, S.R.

    1991-03-01

    Aircraft constitute a unique environment which places stringent requirements on the instruments used to measure the concentrations of atmospheric trace gases and aerosols. Some of these requirements such as minimization of size, weight, and power consumption are general; others are specific to individual techniques. This review presents the basic principles and considerations governing the deployment of trace gas and aerosol instrumentation on an aircraft. An overview of common instruments illustrates these points and provides guidelines for designing and using instruments on aircraft-based measurement programs.

  18. Aircraft Measurements for Understanding Air-Sea Coupling and Improving Coupled Model Predictions

    DTIC Science & Technology

    2013-09-30

    concern since we do not expect to measure turbulence at that high altitude). The LI-COR 7200 and Krypton fast humidity data were calibrated against...measurements. Our modified krypton hygrometer is a good alternative to the obsolete AIR Lyman-alpha for fast-response humidity measurements from research

  19. Vortex dynamics behind cruising aircraft studied by a ground-based scanning lidar and airborne in-situ measurements

    NASA Astrophysics Data System (ADS)

    Sussmann, Ralf; Jaeger, Horst

    1997-05-01

    By LIDAR and CCD camera analysis the geometrical evolution of a vortex phase contrail (descent rate Vd equals 2.7 m/s, vortex separation D equals 47 m, vertical extension (sigma) z equals 140 m after 77 s) is analyzed. The contrail of a four-engine aircraft is showing a diffuse central wake phenomenon. From coincident in situ measurements all relevant meteorological parameters are characterized. Ambient humidity had been close to ice saturation. From this a non-exhaust formation of ice can be excluded. Also the mechanism of non- entrainment of exhaust into the vortices is excluded of being responsible for the observed early onset of the central wake (870 m behind aircraft). The central wake onset originates from early detrainment starting after a 3/4 roll-up period of the vortex. Baroclinic and shear forces do not contribute to the detrainment (imaginary Brunt-Vaisala-frequency N2 equals negative 3 multiplied by 10-5 s-2, shear dS/dz equals negative 0.01 s-1, bulk Richardson number Ri, equals N2/(dS/dz)2 equals negative 0.3). Ambient turbulence had been fully developed with an inertial range and locally isotropic turbulence for wavenumbers k-equals 0.004 - 0.1 radian/m. The eddy dissipation rate (epsilon) equals 7.4 plus or minus 0.5 multiplied by 10-5 m2s-3 exceeds the values found over the North Atlantic flight corridor at cruising altitude by a factor of 1000. Turbulence was identified as the dominating detrainment mechanism.

  20. Aerosols upwind of Mexico City during the MILAGRO campaign: regional scale biomass burning, dust and volcanic ash from aircraft measurements

    NASA Astrophysics Data System (ADS)

    Junkermann, W.; Steinbrecher, R.

    2009-04-01

    During the MILAGRO Campaign March/April 2006 a series of aircraft flights with the FZK microlight D-MIFU were performed in the area southeast of Mexico City starting from Puebla airport, circling the national park area of Ixtachiuatl and Popocatepetl and scanning the Chalco valley down to Cuautla in the Cuernavaca province. All flights were combined with vertical profiles up to 4500 m a.s.l. in several locations, typically north of volcano Ixtachiuatl on the Puebla side, above Chalco or Tenago del Aire and south of volcano Popocatepetl, either at Cuautla or Atlixco. In Tenango del Aire a ceilometer was additionally operated continuously for characterization of the planetary boundary layer. The aircraft carried a set of aerosol instrumentation, fine and coarse particles and size distributions as well as a 7 wavelength aethalometer. Additionally meteorological parameters, temperature and dewpoint, global radiation and actinic radiation balance, respectively photolysis rates, and ozone concentrations were measured. The instrumentation allowed to characterize the aerosol according to their sources and also their impact on radiation transfer. Biomass burning aerosol, windblown dust and volcanic ash were identified within the upwind area of Mexico City with large differences between the dry season in the first weeks of the campaign and the by far cleaner situation after beginning thunderstorm activity towards the end of the campaign. Also the aerosol characteristics inside and outside the Mexico City basin were often completely different. With wind speeds of ~ 5 m/sec from southerly directions in the Chalco valley the aerosol mixture can reach the City within ~ 2 h. Rural aerosol mixtures from the Cuernavaca plain were mixed during the transport with dust from the MC basin. Very high intensity biomass burning plumes normally reached higher altitudes and produced pyrocumulus clouds. These aerosols were injected mainly into the free troposphere. Within the MC basin a large

  1. REAL-TIME AND INTEGRATED MEASUREMENT OF POTENTIAL HUMAN EXPOSURE TO PARTICLE-BOUND POLYCYCLIC AROMATIC HYDROCARBONS (PAHS) FROM AIRCRAFT EXHAUST

    EPA Science Inventory

    Real-time monitors and low-volume air samplers were used to measure the potential human exposure to airborne polycyclic aromatic hydrocarbon (PAH) concentrations during various flight-related and ground-support activities of C-130H aircraft at an Air National Guard base. Three...

  2. Calibration of the visible and near-infrared channels of the LANDSAT-5 Thematic Mapper using high-altitude aircraft measurements

    NASA Technical Reports Server (NTRS)

    Smith, G. R.; Levin, R. H.; Knoll, J. S.; Koyanagi, R. S.; Wrigley, R. C.

    1990-01-01

    Visible near-infrared sensors mounted on operational satellites now in use do not have on-board full aperture absolute calibration devices. One means of establishing an in-orbit calibration for a satellite sensor is to make simultaneous measurements of a bright, uniform scene along the satellite view vector from a calibrated instrument on board a high altitude aircraft. In the work reported here, aircraft data were recorded over White Sands, New Mexico at satellite overpass time for the LANDSAT-5 Thematic Mapper (TM). A comparison of the coincident aircraft and orbiting satellite data showed the radiometric gain for TM channel 1 had degraded 4.7 percent by August 28, 1985; gains for TM channels 2 and 3 were within 1 percent of prelaunch values.

  3. Summary of measurement results of ozone, methane, and nonmethane hydrocarbons for C-54 aircraft. 1979 Southeastern Virginia Urban Plume Study

    NASA Technical Reports Server (NTRS)

    Cofer, W. R., III; Purgold, G. C.; Gregory, G. L.

    1981-01-01

    Methane, nonmethane hydrocarbon, and ozone data collected in a C-54 aircraft during the 1979 Southeastern Virginia Urban Plume Study are presented. Three major aircraft experiments were flown on five separate days in August collecting 20 hours of flight data. Direct correlation between ozone and hydrocarbon plumes was observed on several occasions.

  4. Aircraft-measured indirect cloud effects from biomass burning smoke in the Arctic and subarctic

    DOE PAGES

    Zamora, Lauren M.; Kahn, R. A.; Cubison, M. J.; ...

    2016-01-21

    The incidence of wildfires in the Arctic and subarctic is increasing; in boreal North America, for example, the burned area is expected to increase by 200–300% over the next 50–100 years, which previous studies suggest could have a large effect on cloud microphysics, lifetime, albedo, and precipitation. However, the interactions between smoke particles and clouds remain poorly quantified due to confounding meteorological influences and remote sensing limitations. Here, we use data from several aircraft campaigns in the Arctic and subarctic to explore cloud microphysics in liquid-phase clouds influenced by biomass burning. Median cloud droplet radii in smoky clouds were ~40–60% smallermore » than in background clouds. Based on the relationship between cloud droplet number (Nliq) and various biomass burning tracers (BBt) across the multi-campaign data set, we calculated the magnitude of subarctic and Arctic smoke aerosol–cloud interactions (ACIs, where ACI = (1/3) × dln(Nliq)/dln(BBt)) to be ~0.16 out of a maximum possible value of 0.33 that would be obtained if all aerosols were to nucleate cloud droplets. Interestingly, in a separate subarctic case study with low liquid water content (~0.02gm–3) and very high aerosol concentrations (2000–3000 cm–3) in the most polluted clouds, the estimated ACI value was only 0.05. In this case, competition for water vapor by the high concentration of cloud condensation nuclei (CCN) strongly limited the formation of droplets and reduced the cloud albedo effect, which highlights the importance of cloud feedbacks across scales. Using our calculated ACI values, we estimate that the smoke-driven cloud albedo effect may decrease local summertime short-wave radiative flux by between 2 and 4 Wm–2 or more under some low and homogeneous cloud cover conditions in the subarctic, although the changes should be smaller in high surface albedo regions of the Arctic. Furthermore, we lastly explore evidence suggesting that

  5. Aircraft-Measured Indirect Cloud Effects from Biomass Burning Smoke in the Arctic and Subarctic

    NASA Technical Reports Server (NTRS)

    Zamora, L. M.; Kahn, R. A.; Cubison, M. J.; Diskin, G. S.; Jimenez, J. L.; Kondo, Y.; McFarquhar, G. M.; Nenes, A.; Thornhill, K. L.; Wisthaler, A.; Zelenyuk, A.; Ziemba, L. D.

    2016-01-01

    The incidence of wildfires in the Arctic and subarctic is increasing; in boreal North America, for example, the burned area is expected to increase by 200-300% over the next 50-100 years, which previous studies suggest could have a large effect on cloud microphysics, lifetime, albedo, and precipitation. However, the interactions between smoke particles and clouds remain poorly quantified due to confounding meteorological influences and remote sensing limitations. Here, we use data from several aircraft campaigns in the Arctic and subarctic to explore cloud microphysics in liquid-phase clouds influenced by biomass burning. Median cloud droplet radii in smoky clouds were approx. 40- 60% smaller than in background clouds. Based on the relationship between cloud droplet number (N(liq)/ and various biomass burning tracers (BBt/ across the multi-campaign data set, we calculated the magnitude of subarctic and Arctic smoke aerosol-cloud interactions (ACIs, where ACI = (1/3) x dln(N(liq))/dln(BBt)) to be approx. 0.16 out of a maximum possible value of 0.33 that would be obtained if all aerosols were to nucleate cloud droplets. Interestingly, in a separate subarctic case study with low liquid water content (0.02 gm/cu m and very high aerosol concentrations (2000- 3000/ cu cm in the most polluted clouds, the estimated ACI value was only 0.05. In this case, competition for water vapor by the high concentration of cloud condensation nuclei (CCN) strongly limited the formation of droplets and reduced the cloud albedo effect, which highlights the importance of cloud feedbacks across scales. Using our calculated ACI values, we estimate that the smoke-driven cloud albedo effect may decrease local summertime short-wave radiative flux by between 2 and 4 W/sq m or more under some low and homogeneous cloud cover conditions in the subarctic, although the changes should be smaller in high surface albedo regions of the Arctic.We lastly explore evidence suggesting that numerous northern

  6. Aircraft-measured indirect cloud effects from biomass burning smoke in the Arctic and subarctic

    SciTech Connect

    Zamora, Lauren M.; Kahn, R. A.; Cubison, M. J.; Diskin, G. S.; Jimenez, J. L.; Kondo, Y.; McFarquhar, G. M.; Nenes, A.; Thornhill, K. L.; Wisthaler, A.; Zelenyuk, A.; Ziemba, L. D.

    2016-01-21

    The incidence of wildfires in the Arctic and subarctic is increasing; in boreal North America, for example, the burned area is expected to increase by 200–300% over the next 50–100 years, which previous studies suggest could have a large effect on cloud microphysics, lifetime, albedo, and precipitation. However, the interactions between smoke particles and clouds remain poorly quantified due to confounding meteorological influences and remote sensing limitations. Here, we use data from several aircraft campaigns in the Arctic and subarctic to explore cloud microphysics in liquid-phase clouds influenced by biomass burning. Median cloud droplet radii in smoky clouds were ~40–60% smaller than in background clouds. Based on the relationship between cloud droplet number (Nliq) and various biomass burning tracers (BBt) across the multi-campaign data set, we calculated the magnitude of subarctic and Arctic smoke aerosol–cloud interactions (ACIs, where ACI = (1/3) × dln(Nliq)/dln(BBt)) to be ~0.16 out of a maximum possible value of 0.33 that would be obtained if all aerosols were to nucleate cloud droplets. Interestingly, in a separate subarctic case study with low liquid water content (~0.02gm–3) and very high aerosol concentrations (2000–3000 cm–3) in the most polluted clouds, the estimated ACI value was only 0.05. In this case, competition for water vapor by the high concentration of cloud condensation nuclei (CCN) strongly limited the formation of droplets and reduced the cloud albedo effect, which highlights the importance of cloud feedbacks across scales. Using our calculated ACI values, we estimate that the smoke-driven cloud albedo effect may decrease local summertime short-wave radiative flux by between 2 and 4 Wm–2 or more under some low and homogeneous cloud cover conditions in the subarctic, although the changes should be smaller in high

  7. Aircraft-Measured Indirect Cloud Effects from Biomass Burning Smoke in the Arctic and Subarctic

    NASA Technical Reports Server (NTRS)

    Zamora, Lauren; Kahn, R. A.; Cubison, M. C.; Diskin, G. S.; Jimenez, J. L.; Kondo, Y.; McFarquhar, G. M.; Nenes, A.; Wisthaler, A.; Zelenyuk, A.; Ziemba, L.

    2016-01-01

    The incidence of wildfires in the Arctic and subarctic is increasing; in boreal North America, for example, the burned area is expected to increase by 200-300 over the next 50-100 years, which previous studies suggest could have a large effect on cloud microphysics, lifetime, albedo, and precipitation. However, the interactions between smoke particles and clouds remain poorly quantified due to confounding meteorological influences and remote sensing limitations. Here, we use data from several aircraft campaigns in the Arctic and subarctic to explore cloud microphysics in liquid-phase clouds influenced by biomass burning. Median cloud droplet radii in smoky clouds were 50 smaller than in background clouds. Based on the relationship between cloud droplet number (N(liq))/ and various biomass burning tracers (BBt/ across the multi-campaign dataset, we calculated the magnitude of subarctic and Arctic smoke aerosol-cloud interactions (ACI, where ACI = (1/3) x dln(N(liq))/dln(BBt)) to be 0.12 out of a maximum possible value of 0.33 that would be obtained if all aerosols were to nucleate cloud droplets. Interestingly, in a separate subarctic case study with low liquid water content (0.02 gm/ cu m) and very high aerosol concentrations (2000-3000 cu m) in the most polluted clouds, the estimated ACI value was only 0.06. In this case, competition for water vapor by the high concentration of CCN strongly limited the formation of droplets and reduced the cloud albedo effect, which highlights the importance of cloud feedbacks across scales. Using our calculated ACI values, we estimate that the smoke-driven cloud albedo effect may decrease shortwave radiative flux by 2 and 4 W/sq or more under some low and homogeneous cloud cover conditions in the subarctic, although the changes should be smaller in high surface albedo regions of the Arctic. We lastly show evidence to suggest that numerous northern latitude background Aitken particles can interact with combustion particles

  8. Aircraft-measured indirect cloud effects from biomass burning smoke in the Arctic and subarctic

    NASA Astrophysics Data System (ADS)

    Zamora, L. M.; Kahn, R. A.; Cubison, M. J.; Diskin, G. S.; Jimenez, J. L.; Kondo, Y.; McFarquhar, G. M.; Nenes, A.; Thornhill, K. L.; Wisthaler, A.; Zelenyuk, A.; Ziemba, L. D.

    2016-01-01

    The incidence of wildfires in the Arctic and subarctic is increasing; in boreal North America, for example, the burned area is expected to increase by 200-300 % over the next 50-100 years, which previous studies suggest could have a large effect on cloud microphysics, lifetime, albedo, and precipitation. However, the interactions between smoke particles and clouds remain poorly quantified due to confounding meteorological influences and remote sensing limitations. Here, we use data from several aircraft campaigns in the Arctic and subarctic to explore cloud microphysics in liquid-phase clouds influenced by biomass burning. Median cloud droplet radii in smoky clouds were ˜ 40-60 % smaller than in background clouds. Based on the relationship between cloud droplet number (Nliq) and various biomass burning tracers (BBt) across the multi-campaign data set, we calculated the magnitude of subarctic and Arctic smoke aerosol-cloud interactions (ACIs, where ACI = (1/3) × dln(Nliq)/dln(BBt)) to be ˜ 0.16 out of a maximum possible value of 0.33 that would be obtained if all aerosols were to nucleate cloud droplets. Interestingly, in a separate subarctic case study with low liquid water content ( ˜ 0.02 g m-3) and very high aerosol concentrations (2000-3000 cm-3) in the most polluted clouds, the estimated ACI value was only 0.05. In this case, competition for water vapor by the high concentration of cloud condensation nuclei (CCN) strongly limited the formation of droplets and reduced the cloud albedo effect, which highlights the importance of cloud feedbacks across scales. Using our calculated ACI values, we estimate that the smoke-driven cloud albedo effect may decrease local summertime short-wave radiative flux by between 2 and 4 W m-2 or more under some low and homogeneous cloud cover conditions in the subarctic, although the changes should be smaller in high surface albedo regions of the Arctic. We lastly explore evidence suggesting that numerous northern

  9. Aircraft-measured indirect cloud effects from biomass burning smoke in the Arctic and subarctic

    NASA Astrophysics Data System (ADS)

    Zamora, L. M.; Kahn, R. A.; Cubison, M. J.; Diskin, G. S.; Jimenez, J. L.; Kondo, Y.; McFarquhar, G. M.; Nenes, A.; Thornhill, K. L.; Wisthaler, A.; Zelenyuk, A.; Ziemba, L. D.

    2015-08-01

    The incidence of wildfires in the Arctic and subarctic is increasing; in boreal North America, for example, the burned area is expected to increase by 200-300 % over the next 50-100 years, which previous studies suggest could have a large effect on cloud microphysics, lifetime, albedo, and precipitation. However, the interactions between smoke particles and clouds remain poorly quantified due to confounding meteorological influences and remote sensing limitations. Here, we use data from several aircraft campaigns in the Arctic and subarctic to explore cloud microphysics in liquid-phase clouds influenced by biomass burning. Median cloud droplet radii in smoky clouds were ~ 50 % smaller than in background clouds. Based on the relationship between cloud droplet number (Nliq) and various biomass burning tracers (BBt) across the multi-campaign dataset, we calculated the magnitude of subarctic and Arctic smoke aerosol-cloud interactions (ACI, where ACI = (1/3) × d ln (Nliq) / d ln (BBt)) to be ~ 0.12 out of a maximum possible value of 0.33 that would be obtained if all aerosols were to nucleate cloud droplets. Interestingly, in a separate subarctic case study with low liquid water content (~ 0.02 g m-3) and very high aerosol concentrations (2000-3000 cm-3) in the most polluted clouds, the estimated ACI value was only 0.06. In this case, competition for water vapor by the high concentration of CCN strongly limited the formation of droplets and reduced the cloud albedo effect, which highlights the importance of cloud feedbacks across scales. Using our calculated ACI values, we estimate that the smoke-driven cloud albedo effect may decrease shortwave radiative flux by 2-4 W m-2 or more under some low and homogeneous cloud cover conditions in the subarctic, although the changes should be smaller in high surface albedo regions of the Arctic. We lastly show evidence to suggest that numerous northern latitude background Aitken particles can interact with combustion particles

  10. Development and Deployment of Unmanned Aircraft Instrumentation for Measuring Quantities Related to Land Surface-Atmosphere Interactions

    NASA Astrophysics Data System (ADS)

    de Boer, G.; Lawrence, D.; Elston, J.; Argrow, B. M.; Palo, S. E.; Curry, N.; Finamore, W.; Mack, J.; LoDolce, G.; Schmid, B.; Long, C. N.; Bland, G.; Maslanik, J. A.; Gao, R. S.; Telg, H.; Semmer, S.; Maclean, G.; Ivey, M.; Hock, T. F.; Bartram, B.; Bendure, A.; Stachura, M.

    2015-12-01

    Use of unmanned aircraft systems (UAS) in evaluation of geophysical parameters is expanding at a rapid rate. Despite limitation imposed by necessary regulations related to operation of UAS in the federal airspace, several groups have developed and deployed a variety of UAS and the associated sensors to make measurements of the atmosphere, land surface, ocean and cryosphere. Included in this grouping is work completed at the University of Colorado - Boulder, which has an extended history of operating UAS and expanding their use in the earth sciences. Collaborative projects between the department of Aerospace Engineering, the Cooperative Institute for Research in Environmental Sciences (CIRES), the Research and Engineering Center for Unmanned Vehicles (RECUV), the National Oceanographic and Atmospheric Administration (NOAA) and National Centers for Atmospheric Research (NCAR) have resulted in deployment of UAS to a variety of environments, including the Arctic. In this presentation, I will give an overview of some recent efforts lead by the University of Colorado to develop and deploy a variety of UAS. Work presented will emphasize recent campaigns and instrument development and testing related to understanding the land-atmosphere interface. Specifically, information on systems established for evaluating surface radiation (including albedo), turbulent exchange of water vapor, heat and gasses, and aerosol processes will be presented, along with information on the use of terrestrial ecosystem sensing to provide critical measurments for the evaluation of lower atmospheric flux measurements.

  11. A comparison of two independent measurements and analysis of jet aircraft flyover noise

    NASA Technical Reports Server (NTRS)

    Hosier, R. N.

    1977-01-01

    Flyover noise measurements were made simultaneously by two groups. The measurements were made close to one another for the same flyover conditions and with similar measurement procedures, but with different acoustic equipment and personnel. Each group also independently processed the data in accordance with FAR 36 procedures, indluding corrections to reference meteorological, performance, and flight-path conditions. Measured and corrected data, from 24 controlled flyovers processed by both groups, are compared and the differences in the results obtained by the two groups are discussed. It is observed that the average value of the difference between the groups' measured acoustic descriptors (PNL, PNLTM, and EPNL) was less than or = 0.8 db; the average difference for the corrected descriptors (PNL, PNLTM, and EPNL) was less than or = 1.5 db. Causes of the differences were found to be mainly related to different spectrum extrapolation and preemphasis techniques used by the two groups.

  12. Considerations for osmolality measurement under elevated pCO(2): comparison of vapor pressure and freezing point osmometry.

    PubMed

    Schmelzer, A E; deZengotita, V M; Miller, W M

    2000-01-20

    Osmolality increases with pCO(2) in bioreactors with pH control, and it has been shown that osmolality compensation by decreasing the basal NaCl concentration partially mitigates the adverse effects of elevated pCO(2) on animal cell growth, protein production, and glycosylation. Thus, measurement of osmolality is important for a complete characterization of the culture environment under elevated pCO(2). However, osmolality measurement may be compromised by CO(2) evolution. Freezing point depression and vapor pressure depression osmometry were directly compared for the measurement of osmolality in samples at elevated pCO(2) (up to 250 mmHg) and at a variety of pH values (6.7-7.5). More extensive degassing may be expected with the vapor pressure osmometer due to the smaller sample volume and larger surface area employed. However, both types of osmometer yielded similar results for all pCO(2) and pH values studied. Moreover, the measured values agreed with osmolality values calculated using a semi-empirical model. Further analysis showed that, while sample degassing may result in a large decrease in pCO(2), there is little associated decrease in osmolality. The great majority of total CO(2) in solution is present as bicarbonate (HCO(3)(-)). Although a small amount of HCO(3)(-) is converted to CO(2) to compensate for CO(2) evolution, further depletion of HCO(3)(-) is inhibited by the associated increase in medium pH and by the need for HCO(3)(-) to maintain charge neutrality in solution. This explanation is consistent with the observed similarity in osmolality values for the two types of osmometer. It was also observed that osmolality did not change in samples that were frozen at -20 degrees C for up to 1 year.

  13. Noncontact methods for measuring water-surface elevations and velocities in rivers: Implications for depth and discharge extraction

    USGS Publications Warehouse

    Nelson, Jonathan M.; Kinzel, Paul J.; McDonald, Richard R.; Schmeeckle, Mark

    2016-01-01

    Recently developed optical and videographic methods for measuring water-surface properties in a noninvasive manner hold great promise for extracting river hydraulic and bathymetric information. This paper describes such a technique, concentrating on the method of infrared videog- raphy for measuring surface velocities and both acoustic (laboratory-based) and laser-scanning (field-based) techniques for measuring water-surface elevations. In ideal laboratory situations with simple flows, appropriate spatial and temporal averaging results in accurate water-surface elevations and water-surface velocities. In test cases, this accuracy is sufficient to allow direct inversion of the governing equations of motion to produce estimates of depth and discharge. Unlike other optical techniques for determining local depth that rely on transmissivity of the water column (bathymetric lidar, multi/hyperspectral correlation), this method uses only water-surface information, so even deep and/or turbid flows can be investigated. However, significant errors arise in areas of nonhydrostatic spatial accelerations, such as those associated with flow over bedforms or other relatively steep obstacles. Using laboratory measurements for test cases, the cause of these errors is examined and both a simple semi-empirical method and computational results are presented that can potentially reduce bathymetric inversion errors.

  14. Overview of the trace gas measurements on board the Citation aircraft during the intensive field phase of INDOEX

    NASA Astrophysics Data System (ADS)

    de Gouw, J. A.; Warneke, C.; Scheeren, H. A.; van der Veen, C.; Bolder, M.; Scheele, M. P.; Williams, J.; Wong, S.; Lange, L.; Fischer, H.; Lelieveld, J.

    2001-11-01

    During the intensive field phase of the Indian Ocean Experiment (INDOEX), measurements of the atmospheric chemical and aerosol composition over the Indian Ocean were performed from a Cessna Citation aircraft. Measurements were performed during February and March 1999 over the northern Indian Ocean from 70°E to 80°E, and from 8°N to 8°S in the 0-13 km altitude range. An overview of the trace gas measurements is presented. In the lowest 3 km the highest levels of pollution were found during February 1999, mostly originating from northeastern India and southeastern Asia. Lower levels of pollution were detected in March 1999, when the sampled air mostly originated from the Arabian Sea region. The mixing ratios of a number of trace compounds, indicative of biomass burning, were well correlated. The pollutant emission factors inferred from the measurements are consistent with literature values for fire plumes, confirming that the residential use of biofuels in Asia is a major source of gaseous pollutants to the atmosphere over the Indian Ocean, in accord with emission databases. The removal of reactive trace gases was studied over an extended area without interfering local emissions, and is shown to be governed by photochemical processes rather than by mixing and deposition. At intermediate altitudes of 3-8 km the mixing ratios of all trace gases other than ozone were generally lower, and the measurements suggest that the photochemical processing of these air masses is much more extensive than in the 0-3 km range. In the 8-13 km altitude range some evidence is obtained for the importance of convective cloud systems in the transport of gaseous pollutants to the upper troposphere.

  15. HALO aircraft measurements of East Asian anthropogenic SO2 import into the lower stratosphere by a warm conveyor belt uplift

    NASA Astrophysics Data System (ADS)

    Schlager, H.; Arnold, F.; Aufmhoff, H.; Baumann, R.; Pirjola, L.; Roiger, A.; Sailer, T.; Wirth, M.; Schumann, U.

    2012-04-01

    We report on a case study of anthropogenic SO2 pollution transport into the lower stratosphere from East Asian source regions. The pollution layer was observed over Central Europe by measurements from the new German research aircraft HALO. The layer contained enhanced SO2, HNO3 and water vapor and caused increased Lidar backscatter radiation. Meteorological analysis and air mass transport and dispersion model simulations reveal that the detected pollutants were released from ground-based sources in East-China, South-Korea, and Japan. The pollution plume was uplifted by a warm conveyor belt associated with a West-Pacific cyclone and finally injected into the lower stratosphere. Our HALO measurements were performed 5 days after the air mass uplift event, when significant parts of the Northern Hemisphere were already covered by the pollution plume. Accompanying trajectory chemistry and aerosol box model simulations indicate that H2SO4/H2O aerosol droplets were generated in the SO2-rich plume and grew to sizes large enough to explain the observed increased Lidar backscatter signal. Implications of the SO2 transport pathway into the lower stratosphere presented in this study will be discussed.

  16. Effects of Aircraft Wake Dynamics on Measured and Simulated NO(x) and HO(x) Wake Chemistry. Appendix B

    NASA Technical Reports Server (NTRS)

    Lewellen, D. C.; Lewellen, W. S.

    2001-01-01

    High-resolution numerical large-eddy simulations of the near wake of a B757 including simplified NOx and HOx chemistry were performed to explore the effects of dynamics on chemistry in wakes of ages from a few seconds to several minutes. Dilution plays an important basic role in the NOx-O3 chemistry in the wake, while a more interesting interaction between the chemistry and dynamics occurs for the HOx species. These simulation results are compared with published measurements of OH and HO2 within a B757 wake under cruise conditions in the upper troposphere taken during the Subsonic Aircraft Contrail and Cloud Effects Special Study (SUCCESS) mission in May 1996. The simulation provides a much finer grained representation of the chemistry and dynamics of the early wake than is possible from the 1 s data samples taken in situ. The comparison suggests that the previously reported discrepancy of up to a factor of 20 - 50 between the SUCCESS measurements of the [HO2]/[OH] ratio and that predicted by simplified theoretical computations is due to the combined effects of large mixing rates around the wake plume edges and averaging over volumes containing large species fluctuations. The results demonstrate the feasibility of using three-dimensional unsteady large-eddy simulations with coupled chemistry to study such phenomena.

  17. Nitric oxide, water vapor, and ozone in the atmosphere as measured in SITU from an aircraft

    NASA Technical Reports Server (NTRS)

    Briehl, D.; Ridley, B. A.; Hilsenrath, E.; Schiff, H. I.

    1975-01-01

    As part of the instrument evaluation plan for the NASA Global Atmospheric Sampling Program, prototype instruments were tested aboard the NASA Convair 990 during four flights in January and February of 1974. All the data were taken in maritime air between Hawaii and San Francisco and between Hawaii and 155 deg W, 35 deg N. A chemiluminescent instrument was used to measure nitric oxide. Water vapor, which was measured by using an aluminum oxide hygrometer, ranged from 5.2 micro g/g to saturation. Ozone was measured by an instrument using the ultraviolet absorption technique and ranged up to 235 ppbv. Typical temporal plots of the concentrations of the three constituents are presented. All the constituents showed considerable spatial and day-to-day variation in concentration at each altitude flown. Measurements of the three constituents were made simultaneously at various altitudes between 7.6 and 12.5 km.

  18. AGARD Flight Test Instrumentation Series. Volume 8. Linear and Angular Position Measurement of Aircraft Components

    DTIC Science & Technology

    1977-01-01

    4.-" Output voltages for cae revolution of the shaft of an eleo- trical eleymb- speed qanchic (only one pha&e of each output 0ho is ~m)This iunohro...measurements at higher shaft -rotation speeds , up to som. tnousands of degrees per second, special rate-compensated converters are available (Ref. (21...varters can have accuracies of + 2 minutes of arc under these circumstances. For accurate measurements at higher shaft -rotation speeds up to some thousands

  19. Measurements of the tonal component of cavity noise and comparison with theory. [aircraft noise

    NASA Technical Reports Server (NTRS)

    Block, P. J. W.

    1977-01-01

    The frequency of the tonal noise generated by a flow-excited rectangular cavity was measured using Mach numbers ranging from 0.05 to 0.40, and cavity length-to-depth ratios varying from 0.1 to 8. The data are used to evaluate a current prediction method, and good agreement is shown. Measurements of the minimum streamwise cavity length required for oscillation were also made.

  20. Ground- and aircraft-based cirrus cloud measurements using lidar and high-spectral-resolution FTS during the AFWEX 2000 field campaign

    NASA Astrophysics Data System (ADS)

    DeSlover, Daniel H.; Turner, David; Whiteman, David N.; Smith, William L.

    2002-09-01

    The ARM-FIRE Water Vapor Experiment (AFWEX) was conducted during November-December 2000 at the Southern Great Plains (SGP) Cloud and Radiation Testbed (CART). A cirrus event which occurred on 7-8 December was analyzed using ground- and aircraft-based measurements. The ground-based Atmospheric Emitted Radiance Interferometer (AERI) and NPOESS Airborne Sounder Testbed-Interferometer (NAST-I) are high spectral resolution interferometers which measure downwelling and upwelling infrared radiation, respectively. Analysis between water vapor absorption lines within the 8 to 12 micrometers atmospheric window allow inversion of the radiative transfer equation to derive the cirrus cloud optical depth. These data will be compared to ground-based Raman lidar (GSFC and ARM) measurements of cirrus optical depth. The NAST-I measurements were conducted from the Proteus aircraft.

  1. Measurement of the Streaming Potential Coupling Coefficient in Sandstones Saturated with High Salinity Natural and Artificial Brines at Elevated Temperature

    NASA Astrophysics Data System (ADS)

    Vinogradov, J.; Jackson, M.

    2013-12-01

    Streaming potentials are generated by the flow of water through porous rock, and measurements of the streaming potential component of the self-potential (SP) have been proposed to monitor subsurface flow in a number of settings. Interpretation of SP measurements is made easier by an understanding of the coupling between the fluid flow and associated SP current sources, typically characterised using either the streaming potential coupling coefficient (C, in VPa-1) or the excess charge transported by the flow (Q, in Cm-3). Numerous studies report laboratory measurements of the streaming potential coupling coefficient in intact rock samples of various lithology and mineralogy at laboratory temperature. However, in many subsurface settings, such as deep saline aquifers, geothermal fields, and hydrocarbon reservoirs, temperatures are considerably higher. Yet published measurements of streaming potential at elevated temperature are sparse, and the temperature dependence of the streaming potential coupling coefficient and associated zeta potential exhibits contradictory and inconsistent behaviour. Moreover, the measurements were obtained using simple NaCl or KCl electrolytes at relatively low concentration (typically up to one tenth of seawater salinity) but natural brines are often significantly more saline and contain a wide variety of ionic species. We report measurements of the streaming potential on intact sandstone core samples saturated with high salinity natural and artificial brines at elevated temperatures. We measure streaming potential using an experimental set-up that incorporates in-situ measurements of saturated rock conductivity, brine temperature, pressure difference and voltage at temperatures up to 160oC. At temperatures below 100oC we also measure the brine pH and electrical conductivity. Using constant rate pumping we obtain the streaming potential coupling coefficient from the gradient of a linear relationship between pressure and voltage difference

  2. Shipboard Sunphotometer Measurements of Aerosol Optical Depth During ACE-2 and Comparison with Selected Ship, Aircraft and Satellite Measurements

    NASA Technical Reports Server (NTRS)

    Livingston, J. M.; Kapustin, V. N.; Schmid, B.; Russell, P. B.; Quinn, P. K.; Bates, T. S.; Durkee, P. A.; Nielsen, K.; Freudenthaler, V.; Wiegner, M.; Covert, D. S.

    2000-01-01

    We present analyses of aerosol optical depth (AOD) measurements taken with a shipboard six-channel tracking sunphotometer during ACE-2. For 10 July 1997, results are also shown for measurements acquired 70 km from the ship with a fourteen-channel airborne tracking sunphotometer.

  3. Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM): A Year 2000 Global Baseline for Measuring Topographic Change

    NASA Astrophysics Data System (ADS)

    Crippen, R. E.

    2002-12-01

    The SRTM DEM is the first near-global, high-resolution elevation model. The data were acquired in February 2000 aboard the Space Shuttle Endeavour and cover the Earth's land masses between 60N and 56S latitudes at about 30 meters spatial resolution. The data are a virtual global snapshot in that they were acquired in about 10 days by a single sensor. Absolute vertical accuracy was targeted at 16 meters. However, spatially broad temporal changes in topography have been detected and measured down to about one-meter precision by comparing the SRTM DEM to the USGS National Elevation Dataset (NED). NED has similar spatial properties, but was independently derived, commonly years (or decades) earlier. Such changes already noted include those related to volcanic processes, alluvial fan deposition, subsidence related to oil extraction, and direct anthropogenic changes such as landfills and major road cuts and fills. Large tectonic changes in topography are likewise potentially evident in such comparisons. New and forthcoming satellites include capabilities to produce elevation models that can be used to detect and measure ongoing and future topographic change when compared to the SRTM DEM. For example, the ASTER instrument on the Terra satellite (launched in 1999) produces targeted DEMs, and SPOT-5 (launched in 2002) is expected to produce a global DEM over a five-year period. Both of these DEM sources (and the NED and others) use optical wavelength sensors which may "observe a different surface" than the SRTM radar, particularly in heavily vegetated areas, and this must be considered in making the comparisons. However, having a "before" data set is often the roadblock in measuring change, and SRTM has now provided the first detailed "before" DEM for most of Earth's land surface.

  4. Method and apparatus for measuring surface contour on parts with elevated temperatures

    DOEpatents

    Horvath, Mark S.; Nance, Roy A.; Cohen, George H.; Fodor, George

    1991-01-01

    The invention is directed to a method and apparatus for measuring the surface contour of a test piece, such as the bow of a radioactive fuel rod, which is completely immersed in water. The invention utilizes ultrasonic technology and is capable of measuring surface contours of test pieces which are at a higher temperature than the surrounding water. The presence of a test piece at a higher temperature adversely affects the distance measurements by causing thermal variations in the water near the surface of the test piece. The contour measurements depend upon a constant temperature of the water in the path of the ultrasonic wave to provide a constant acoustical velocity (the measurement is made by the time of flight measurement for an ultrasonic wave). Therefore, any variations of water temperature near the surface will introduce errors degrading the measurement. The present invention overcomes these problems by assuring that the supply of water through which the ultrasonic waves travel is at a predetermined and constant temperature.

  5. Lightning electric field measurements which correlate with strikes to the NASA F-106B aircraft, 22 July 1980

    NASA Technical Reports Server (NTRS)

    Levine, D. M.

    1981-01-01

    Ground-based data collected on lightning monitoring equipment operated by Goddard Space Flight Center at Wallops Island, Virginia, during a storm being monitored by NASA's F-106B, are presented. The slow electric field change data and RF radiation data were collected at the times the lightning monitoring equipment on the aircraft was triggered. The timing of the ground-based events correlate well with events recorded on the aircraft and provide an indication of the type of flash with which the aircraft was involved.

  6. Correlation of predicted and measured thermal stresses on an advanced aircraft structure with similar materials

    NASA Technical Reports Server (NTRS)

    Jenkins, J. M.

    1979-01-01

    A laboratory heating test simulating hypersonic heating was conducted on a heat-sink type structure to provide basic thermal stress measurements. Six NASTRAN models utilizing various combinations of bar, shear panel, membrane, and plate elements were used to develop calculated thermal stresses. Thermal stresses were also calculated using a beam model. For a given temperature distribution there was very little variation in NASTRAN calculated thermal stresses when element types were interchanged for a given grid system. Thermal stresses calculated for the beam model compared similarly to the values obtained for the NASTRAN models. Calculated thermal stresses compared generally well to laboratory measured thermal stresses. A discrepancy of signifiance occurred between the measured and predicted thermal stresses in the skin areas. A minor anomaly in the laboratory skin heating uniformity resulted in inadequate temperature input data for the structural models.

  7. Wind tunnel measurements of three-dimensional wakes of buildings. [for aircraft safety applications

    NASA Technical Reports Server (NTRS)

    Logan, E., Jr.; Lin, S. H.

    1982-01-01

    Measurements relevant to the effect of buildings on the low level atmospheric boundary layer are presented. A wind tunnel experiment was undertaken to determine the nature of the flow downstream from a gap between two transversely aligned, equal sized models of rectangular cross section. These building models were immersed in an equilibrium turbulent boundary layer which was developed on a smooth floor in a zero longitudinal pressure gradient. Measurements with an inclined (45 degree) hot-wire were made at key positions downstream of models arranged with a large, small, and no gap between them. Hot-wire theory is presented which enables computation of the three mean velocity components, U, V and W, as well as Reynolds stresses. These measurements permit understanding of the character of the wake downstream of laterally spaced buildings. Surface streamline patterns obtained by the oil film method were used to delineate the separation region to the rear of the buildings for a variety of spacings.

  8. Aircraft measurements of electrified clouds at Kennedy Space Center. Part 1: 1988 flights

    NASA Technical Reports Server (NTRS)

    Jones, J. J.; Winn, W. P.; Hunyady, S. J.; Moore, C. B.; Bullock, J. W.

    1990-01-01

    During the fall of 1988, a Schweizer 845 airplane equipped to measure electric field and other meteorological parameters flew over Kennedy Space Center in a program to study clouds defined in the existing launch retriction requirements. The special purpose test vehicle for atmospheric research (SPTVAR) was suitable for flights through thunderclouds and was instrumented to measure all three components of the ambient electric vector. The main goals of the project were: (1) to develop and demonstrate techniques for measuring the electric field aloft and locate regions of charge during flight; (2) to characterize the electrical conditions within and near clouds that are presently identified as a threat to space launch vehicles; and (3) to study the correlation between the electric field aloft and that at Kennedy Space Center's ground-based field mill network for a variety of electrified clouds.

  9. Combined Aircraft and Satellite-Derived Storm Electric Current and Lightning Rates Measurements and Implications for the Global Electric Circuit

    NASA Technical Reports Server (NTRS)

    Mach, Douglas M.; Blakeslee, Richard J.; Bateman, Monte G.

    2010-01-01

    Using rotating vane electric field mills and Gerdien capacitors, we measured the electric field profile and conductivity during 850 overflights of electrified shower clouds and thunderstorms spanning regions including the Southeastern United States, the Western Atlantic Ocean, the Gulf of Mexico, Central America and adjacent oceans, Central Brazil, and the South Pacific. The overflights include storms over land and ocean, with and without lightning, and with positive and negative fields above the storms. The measurements were made with the NASA ER-2 and the Altus-II high altitude aircrafts. Peak electric fields, with lightning transients removed, ranged from -1.0 kV/m to 16 kV/m, with a mean value of 0.9 kV/m. The median peak field was 0.29 kV/m. Integrating our electric field and conductivity data, we determined total conduction currents and flash rates for each overpass. With knowledge of the storm location (land or ocean) and type (with or without lightning), we determine the mean currents by location and type. The mean current for ocean storms with lightning is 1.6 A while the mean current for land storms with lightning is 1.0 A. The mean current for oceanic storms without lightning (i.e., electrified shower clouds) is 0.39 A and the mean current for land storms without lightning is 0.13 A. Thus, on average, land storms with or without lightning have about half the mean current as their corresponding oceanic storm counterparts. Over three-quarters (78%) of the land storms had detectable lightning, while less than half (43%) of the oceanic storms had lightning. We did not find any significant regional or latitudinal based patterns in our total conduction currents. By combining the aircraft derived storm currents and flash rates with diurnal lightning statistics derived from the Lightning Imaging Sensor (LIS) and Optical Transient Detector (OTD) low Earth orbiting satellites, we reproduce the diurnal variation in the global electric circuit (i.e., the Carnegie

  10. Quantifying particle size and turbulent scale dependence of dust flux in the Sahara using aircraft measurements

    NASA Astrophysics Data System (ADS)

    Rosenberg, Philip D.; Parker, Douglas J.; Ryder, Claire L.; Marsham, John H.; Garcia-Carreras, Luis; Dorsey, James R.; Brooks, Ian M.; Dean, Angela R.; Crosier, Jonathon; McQuaid, James B.; Washington, Richard

    2014-06-01

    The first size-resolved airborne measurements of dust fluxes and the first dust flux measurements from the central Sahara are presented and compared with a parameterization by Kok (2011a). High-frequency measurements of dust size distribution were obtained from 0.16 to 300 µm diameter, and eddy covariance fluxes were derived. This is more than an order of magnitude larger size range than previous flux estimates. Links to surface emission are provided by analysis of particle drift velocities. Number flux is described by a -2 power law between 1 and 144 µm diameter, significantly larger than the 12 µm upper limit suggested by Kok (2011a). For small particles, the deviation from a power law varies with terrain type and the large size cutoff is correlated with atmospheric vertical turbulent kinetic energy, suggesting control by vertical transport rather than emission processes. The measured mass flux mode is in the range 30-100 µm. The turbulent scales important for dust flux are from 0.1 km to 1-10 km. The upper scale increases during the morning as boundary layer depth and eddy size increase. All locations where large dust fluxes were measured had large topographical variations. These features are often linked with highly erodible surface features, such as wadis or dunes. We also hypothesize that upslope flow and flow separation over such features enhance the dust flux by transporting large particles out of the saltation layer. The tendency to locate surface flux measurements in open, flat terrain means these favored dust sources have been neglected in previous studies.

  11. Determination of longitudinal aerodynamic derivatives from steady-state measurement of an aircraft

    NASA Technical Reports Server (NTRS)

    Klein, V.

    1977-01-01

    A method for the estimation of aerodynamic derivatives from steady-state symmetric flight data is developed. The derivatives considered are the longitudinal static stability and control derivatives, damping derivatives due to tail, and the derivatives expressing the speed effect on the lift and pitching moment coefficients. The method is an extension of the well known theory of longitudinal static stability and control, and corresponding flight data interpretation. Measured data is assumed in the form of trim curves and lift vs angle of attack. The expressions for the derivative estimates are in the form of algebraic relationships containing known constants, and directly or indirectly measured quantities.

  12. Measurement of noise and its correlation to performance and geometry of small aircraft propellers

    NASA Astrophysics Data System (ADS)

    Štorch, Vít; Nožička, Jiří; Brada, Martin; Gemperle, Jiří; Suchý, Jakub

    2016-03-01

    A set of small model and UAV propellers is measured both in terms of aerodynamic performance and acoustic noise under static conditions. Apart from obvious correlation of noise to tip speed and propeller diameter the influence of blade pitch, blade pitch distribution, efficiency and shape of the blade is sought. Using the measured performance data a computational model for calculation of aerodynamic noise of propellers will be validated. The range of selected propellers include both propellers designed for nearly static conditions and propellers that are running at highly offdesign conditions, which allows to investigate i.e. the effect of blade stall on both noise level and performance results.

  13. Measurement of Required Power with Human-Powered Aircraft in Take-off Ground Running

    NASA Astrophysics Data System (ADS)

    Yoshikawa, Toshiaki; Sakamoto, Shinsuke; Hori, Kotono; Kusumoto, Hiroshi; Yamamoto, Yasushi; Hattori, Takashi; Sata, Kouta

    In this paper, we propose the method for the measurement of required power and the adjustment of optimum gear ratio in take-off ground running. To get the values of required power and speed, we measured torque of the left side and the right side of pedals, RPM of pedals, and speed of the cockpit frame. In order to improve the take-off speed, some drums were applied, and the optimum gear ratio of the front drum to the rear drum was determined.

  14. Aircraft measurements of the impacts of urban plume on cloud activation properties during GoAmazon - preliminary results

    NASA Astrophysics Data System (ADS)

    Mei, F.; Comstock, J. M.; Wang, J.; Tomlinson, J. M.; Hubbe, J. M.; Schmid, B.; Martin, S. T.; Longo, K.; Kuang, C.; Chand, D.; Pekour, M. S.; Shilling, J. E.

    2014-12-01

    Currently, the indirect effects of atmospheric aerosols remain the most uncertain components in forcing of climate change over the industrial period (IPCC, 2007). This large uncertainty is partially a result of our incomplete understanding of the ability of particles to form cloud droplets under atmospherically relevant supersaturations. One of the objectives of the US Department of Energy (DOE) Green Ocean Amazon Project (GoAmazon) is to understand the influence of the emission from Manaus, a tropical megacity, on aerosol size, concentration, and chemical composition, and their impact on aerosol cloud condensation nuclei (CCN) spectrum. During the GoAmazon study, size distributions, CCN spectra and chemical composition of aerosols both under pristine conditions and inside Manaus plume were measured in-situ from the DOE Gulfstream 1 (G-1) research aircraft during two Intensive Operations Periods, one conducted in the wet season (Feb 22- March 24, 2014) and the other in dry season (Sep 1 - Oct 10, 2014). Aerosol size distributions were measured by a Fast Integrated Mobility Spectrometer (FIMS) and compared with the merged size distribution from two other instruments, an Ultra High Sensitivity Aerosol Spectrometer - Airborne (UHSAS-A, DMT), and a Passive Cavity Aerosol Spectrometer Probe (PCASP-200, DMT). Optical measurements of light scattering by nephelometer and absorption by a particle soot absorption photometer (PSAP) were combined with number/size distributions data in a iterative method, which retrieves the effective imaginary refractive index of the particles at a wavelength of 545 nm. Aerosol chemical composition was characterized using a high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS, Aerodyne Inc.). CCN number concentration was measured by a DMT dual column CCN counter at two supersaturations 0.25% and 0.5%. Based on the aerosol properties mentioned above, CCN closure is carried out. In addition, the sensitivity of calculated CCN

  15. A transient hot-wire instrument for thermal conductivity measurements in electrically conducting liquids at elevated temperatures

    NASA Astrophysics Data System (ADS)

    Alloush, A.; Gosney, W. B.; Wakeham, W. A.

    1982-09-01

    This paper describes a novel type of transient hot-wire cell for thermal conductivity measurements on electrically conducting liquids. A tantalum wire of 25 μm. diameter is used as the sensing element in the cell, and it is insulated from the conducting liquids by an anodic film of tantalum pentoxide, 70 nm thick. The cell is suitable for measurements on conducting liquids at elevated temperatures. The results of test measurements on liquid water at its saturation vapor pressure are reported in order to confirm the correct operation of the thermal conductivity cell. The data, which have an estimated accuracy of ±3%, depart by less than ±1.8% from the correlation proposed by the International Association for the Properties of Steam. Results are also presented for concentrated aqueous solutions of lithium bromide, which are frequently used in absorption refrigerator cycles.

  16. Simultaneous moduli measurement of elastic materials at elevated temperatures using an ultrasonic waveguide method

    NASA Astrophysics Data System (ADS)

    Periyannan, Suresh; Balasubramaniam, Krishnan

    2015-11-01

    A novel technique for simultaneously measuring the moduli of elastic isotropic material, as a function of temperature, using two ultrasonic guided wave modes that are co-generated using a single probe is presented here. This technique can be used for simultaneously measuring Young's modulus (E) and shear modulus (G) of different materials over a wide range of temperatures (35 °C-1200 °C). The specimens used in the experiments have special embodiments (for instance, a bend) at one end of the waveguide and an ultrasonic guided wave generator/detector (transducer) at the other end for obtaining reflected signals in a pulse-echo mode. The orientation of the transducer can be used for simultaneously generating/receiving the L(0,1) and/or T(0,1) using a single transducer in a waveguide on one end. The far end of the waveguides with the embodiment is kept inside a heating device such as a temperature-controlled furnace. The time of flight difference, as a function of uniform temperature distribution region (horizontal portion) of bend waveguides was measured and used to determine the material properties. Several materials were tested and the comparison between values reported in the literature and measured values were found to be in agreement, for both elastic moduli (E and G) measurements, as a function of temperature. This technique provides significant reduction in time and effort over conventional means of measurement of temperature dependence of elastic moduli.

  17. PRELIMINARY RESULTS FROM THE US EPA MERCURY SPECIATION NETWORK AND AIRCRAFT MEASUREMENT CAMPAIGNS

    EPA Science Inventory


    Since EPA measured high concentrations of reactive gaseous mercury (RGM) in emissions from municipal and hospital waste incinerators in 1995, we have been working to elucidate the role of RGM on atmospheric mercury deposition. EPA has recently established automated speciat...

  18. PRELIMINARY RESULTS FROM THE USEPA MERCURY SPECIATION NETWORK AND AIRCRAFT MEASUREMENT CAMPAIGNS

    EPA Science Inventory

    Since EPA measured high concentrations of reactive gaseous mercury (RGM) in emissions from municipal and hospital waste incinerators in 1995, we have been working to elucidate the role of RGM on atmospheric mercury deposition. EPA has recently established automated speciated me...

  19. Chlorine Chemistry of the Lower Stratosphere: Aircraft (ALIAS, ER-2) and Balloon (BLISSs) In-Situ Measurements of HC1,NO(sub 2), andN(sub 2)O for Testing Heterogeneous Chemistry

    NASA Technical Reports Server (NTRS)

    Webster, C.; May, R.; Jaegle, L.; Hu, H.; Scott, D.; Stimpfle, R.; Salawitch, R.; Fahey, D.; Woodbridge, E.; Proffitt, M.; Margitan, J.

    1994-01-01

    Stratospheric concentrations of HC1 measured in the northern hemisphere from the ER-2 aircraft are significantly lower than model predictions using both gas phase and heterogeneous chemistry, but measurements in the southern hemisphere are in much better agreement.

  20. Low elevation angle measurements of the ATS-6 beacons at 4 and 30 GHz

    NASA Astrophysics Data System (ADS)

    Webber, R. V.; McCormick, K. S.

    1980-12-01

    During the westward drift of the ATS-6 satellite in 1976, measurements were made, on the east coast of Newfoundland, of the received signal strengths of the satellite beacon at 4 and 30 GHz. Observations were continued for a total of about 50 h during the 11 day period in which the satellite rose from just below the horizon to about 10 deg above. Data analysis included signal strength distributions, medians, fading ranges and fading rates. No correlation was found between the fading of the two signals. Based on the measured values of fade depths, it is postulated that, for deep fades, the probability of a given fade depth is proportional to frequency. Fade depth statistics are compared with earlier data at 7.3 GHz which were measured at Ottawa

  1. Accuracy of aircraft velocities from inertial navigation systems for application to airborne wind measurements

    NASA Technical Reports Server (NTRS)

    Rhyne, R. H.

    1980-01-01

    An experimental assessment was made of two commercially available inertial navigation systems (INS) with regard to their velocity measuring capability for use in wind, shear, and long-wavelength atmospheric turbulence research. The assessment was based on 52 sets of postflight measurements of velocity (error) during a "Schuler cycle" (84 minutes) while the INS was still operating but the airplane was motionless. Four INS units of one type and two units of another were tested over a period of 2 years after routine research flights similar to air-linetype operations of from 1 to 6 hours duration. The maximum postflight errors found for the 52 cases had a root mean square value of 2.82 m/sec with little or no correlation of error magnitude with flight duration. Using an INS for monitoring ground speed during landway in a predicted high wind shear situation could lead to landing speeds which are dangerously high or low.

  2. Correlation of predicted and measured thermal stresses on a truss-type aircraft structure

    NASA Technical Reports Server (NTRS)

    Jenkins, J. M.; Schuster, L. S.; Carter, A. L.

    1978-01-01

    A test structure representing a portion of a hypersonic vehicle was instrumented with strain gages and thermocouples. This test structure was then subjected to laboratory heating representative of supersonic and hypersonic flight conditions. A finite element computer model of this structure was developed using several types of elements with the NASA structural analysis (NASTRAN) computer program. Temperature inputs from the test were used to generate predicted model thermal stresses and these were correlated with the test measurements.

  3. Acoustical measurements of vibrational relaxation in moist N2 at elevated temperatures

    NASA Technical Reports Server (NTRS)

    Zuckerwar, A. J.; Meredith, R. W.

    1982-01-01

    Sound absorption measurements are conducted by the resonant tube technique to study vibrational relaxation in moist N2 at 301, 343, and 387 K. Analysis of the data shows that improved measurement accuracy at the higher temperatures establishes vibrational-vibrational energy transfer as the operative relaxation path for the de-excitation of N2 by H2O beyond the uncertainty of experimental error. The best-fitted temperature dependence of the vibrational-vibrational rate constant is given, noting that the expression is consistent with seven independent sets of both acoustical and nonacoustical data.

  4. Measurements of the Fuel Mileage of a KC-135 Aircraft with and Without Winglets

    NASA Technical Reports Server (NTRS)

    Temanson, G. E.

    1982-01-01

    The KC-135A Winglet Flight Research and Demonstration Program was a joint effort of the Air Force, NASA and the Boeing Military Airplane Company to flight test winglets on the KC-135A. The primary objective of the program was to verify the cruise performance improvements predicted by analysis and wind tunnel tests. Flight test data were obtained for winglets positioned at 15 deg cant/-2 deg incidence, 0 deg cant/-4 deg incidence, 15 deg cant/-4 deg incidence and for winglets off (baseline). Both fuel mileage and drag measurements were obtained. The 15 deg cant/-4 deg incidence winglet configuration provided the greatest performance improvement. The flight test measured fuel mileage improvement for a 0.78 Mach number was 3.1 percent at 8 x 10(5) pounds W/delta and 5.5 percent at 1.05 x 10(6) pounds W/delta. Correcting the flight measured data for surface pressure differences between wind tunnel and flight resulted in a fuel mileage improvement of 4.4 percent at 8 x 10(5) pounds W/delta and 7.2 percent at 1.05 x 10(6) pounds W/delta. The agreement between the fuel mileage and drag data was excellent.

  5. Air-Sea Fluxes in Terra Nova Bay, Antarctica from In Situ Aircraft Measurements

    NASA Astrophysics Data System (ADS)

    Knuth, S. L.; Cassano, J. J.

    2011-12-01

    In September 2009, the first unmanned aerial vehicles (UAVs) were flown over Terra Nova Bay, Antarctica to collect information regarding air-sea interactions over a wintertime coastal polynya. The UAVs measured wind, temperature, pressure, and relative humidity in flights parallel to the downslope wind flow over the polynya, and in a series of vertical profiles at varying distances from the coast. During three flights on three different days, sufficient measurements were collected to calculate sensible heat, latent heat, and momentum fluxes over varying oceanic surface states, including frazil, pancake, and rafted ice, with background winds greater than 15 ms-1. During the three flights, sensible heat fluxes upwards of 600 Wm-2 were estimated near the coast, with maximum latent heat fluxes near 160 Wm-2 just downwind of the coast. The calculated accelerations due to the momentum flux divergence were on the order of 10-3 ms-2. In addition to the fluxes, changes in the overall momentum budget, including the horizontal pressure gradient force, were also calculated during the three flights. This presentation will summarize the methodology for calculating the fluxes from the UAV data, present the first ever in situ estimates of sensible heat, latent heat, and momentum fluxes and overall momentum budget estimates over Terra Nova Bay, and compare the UAV flux calculations to flux measurements taken during other field campaigns in other regions of the Antarctic, as well as to model estimates over Terra Nova Bay.

  6. Flowfield And Download Measurements And Computation of a Tiltrotor Aircraft In Hover

    NASA Technical Reports Server (NTRS)

    Brand, Albert G.; Peryea, Martin A.; Wood, Tom L.; Meakin, Robert L.

    2001-01-01

    A multipart study of the V-22 hover flowfield was conducted. Testing involved a 0.15-scale semispan model with multiple independent force balance systems. The velocity flowfield surrounding the airframe was measured using a robotic positioning system and anemometer. Both time averaged and cycle-averaged results are reported. It is shown that the fuselage download in hover can be significantly reduced using a small download reduction device. Measurements indicate that the success of the device is attributed to the substantial elimination of tiltrotor fountain flow. As part of.the study, an unsteady CFD prediction is time-averaged, and shown to have excellent agreement in predicting the baseline configuration fountain flow. Some discrepancies at the outboard edge of the rotor are discussed. An &&sessment of an advanced tip shape rotor comp"'Ietes the study. Derived from a nonrotating study, the advanced tip shape rotor was developed and tested on the Bell 0.15 scale semi-span V-22 model. The tip shape was intended to diffuse the tip vortex and reduce BVI noise. Rotor wake vorticity is extracted from the measured velocity dam to show that the advanced tip shape produces a tip vortex that is only slightly more diffuse than the baseline tip blade. The results indicate that nonrotating tests may overpredict the amount of tip vortex diffusion achieved by tip shape design in a rotating environment.

  7. Results of multiband (L, S, Ku band) propagation measurements and model for high elevation angle land mobile satellite channel

    NASA Technical Reports Server (NTRS)

    Parks, M. A. N.; Butt, G.; Evans, Barry G.; Richharia, M.

    1993-01-01

    Signal propagation in the land mobile satellite (LMS) service is an important consideration due to its critical impact on the overall economic and commercial viability of the system. At frequencies allocated for LMS systems, shadowing of the line-of-sight (LOS) signal as well as multipath propagation phenomena can severely impair the link availability. In particular, as most of the studies have shown, the shadowing of LOS signal causes long and deep fades in a variety of mobile environments due to the inherent nature of the channel between the satellite and a mobile. Roadside obstacles, such as buildings, trees, utility poles etc., in the immediate vicinity of a mobile and the surrounding terrain are major sources of signal shadowing in LMS links. Therefore, a proper knowledge of link degradation is essential for cost-effective planning of a satellite based mobile communication system. The results of a propagation campaign undertaken to characterize the fading nature of LMS channel at high elevation angles is presented. It was envisaged that one of the most important physical variables contributing to the amount of LOS signal shadowing is the elevation angle of the satellite. At higher elevation angles to the satellite, less obstructions in the direct satellite-to-mobile path would therefore amount to statistically better link availability. Narrowband channel measurements were carried out at three RF frequencies corresponding to L (1.3 GHz), S (2.32/2.45 GHz), and Ku (10.4 GHz) bands. The campaign itself was divided into two phases to observe the effects of seasonal variation of foliage on the roadside trees. Phase measurements were carried out in September 1991 and in April 1992. Some important aspects from the statistical analysis of the propagation data are presented.

  8. Results of multiband (L, S, Ku band) propagation measurements and model for high elevation angle land mobile satellite channel

    NASA Astrophysics Data System (ADS)

    Parks, M. A. N.; Butt, G.; Evans, Barry G.; Richharia, M.

    1993-08-01

    Signal propagation in the land mobile satellite (LMS) service is an important consideration due to its critical impact on the overall economic and commercial viability of the system. At frequencies allocated for LMS systems, shadowing of the line-of-sight (LOS) signal as well as multipath propagation phenomena can severely impair the link availability. In particular, as most of the studies have shown, the shadowing of LOS signal causes long and deep fades in a variety of mobile environments due to the inherent nature of the channel between the satellite and a mobile. Roadside obstacles, such as buildings, trees, utility poles etc., in the immediate vicinity of a mobile and the surrounding terrain are major sources of signal shadowing in LMS links. Therefore, a proper knowledge of link degradation is essential for cost-effective planning of a satellite based mobile communication system. The results of a propagation campaign undertaken to characterize the fading nature of LMS channel at high elevation angles is presented. It was envisaged that one of the most important physical variables contributing to the amount of LOS signal shadowing is the elevation angle of the satellite. At higher elevation angles to the satellite, less obstructions in the direct satellite-to-mobile path would therefore amount to statistically better link availability. Narrowband channel measurements were carried out at three RF frequencies corresponding to L (1.3 GHz), S (2.32/2.45 GHz), and Ku (10.4 GHz) bands. The campaign itself was divided into two phases to observe the effects of seasonal variation of foliage on the roadside trees. Phase measurements were carried out in September 1991 and in April 1992. Some important aspects from the statistical analysis of the propagation data are presented.

  9. Measurements of Aircraft Wake Vortex Separation at High Arrival Rates and a Proposed New Wake Vortex Separation Philosophy

    NASA Technical Reports Server (NTRS)

    Rutishauser, David; Donohue, George L.; Haynie, Rudolph C.

    2003-01-01

    This paper presents data and a proposed new aircraft wake vortex separation standard that argues for a fundamental re-thinking of international practice. The current static standard, under certain atmospheric conditions, presents an unnecessary restriction on system capacity. A new approach, that decreases aircraft separation when atmospheric conditions dictate, is proposed based upon the availability of new instrumentation and a better understanding of wake physics.

  10. Simulation of the Impact of New Aircraft and Satellite-Based Ocean Surface Wind Measurements on H*Wind Analyses

    NASA Technical Reports Server (NTRS)

    Miller, TImothy L.; Atlas, R. M.; Black, P. G.; Case, J. L.; Chen, S. S.; Hood, R. E.; Johnson, J. W.; Jones, L.; Ruf, C. S.; Uhlborn, E. W.

    2008-01