Science.gov

Sample records for aircraft elevation measurements

  1. Five Year Changes in Surface Elevations Of The Greenland Ice Sheet Measured by Aircraft Laser Altimetry

    NASA Technical Reports Server (NTRS)

    Krabill, W. B.; Frederick, E. B.; Manizade, S. M.; Martin, C. F.; Sonntag, J. G.; Swift, R. N.; Thomas, R. H.; Wright, C. W.; Yungel, J. K.

    2000-01-01

    The Arctic Ice Mapping group (Project AIM) at NASA's Wallops Flight Facility has been conducting systematic topographic surveys of the Greenland Ice Sheet since 1993, using scanning airborne laser altimeters combined with GPS positioning technology. Flight lines were planned to cover all major ice drainage basins, with the intention to repeat the surveys after a 5-year interval in order to detect changes in the ice-sheet volume. The first resurvey was completed in June/July, 1998, along flight lines in the southern half of Greenland which had been first surveyed in 1993. The northern half of the ice sheet will be resurveyed in 1999. The resulting data sets will provide the first comprehensive examination of regional changes in the the surface elevation of the World's second largest ice sheet. This analysis includes the ice sheet fringe areas, which are expected to be much more climatically sensitive than the interior. Data will be presented which demonstrate the combination of the ATM (Airborne Topographic Mapper) sensors and GPS (Global Positioning System) yields measurements which are repeatable at the 10 cm level over baselines in excess of 1000 km.

  2. Aircraft structures research at elevated temperatures

    NASA Technical Reports Server (NTRS)

    Duberg, John E

    1955-01-01

    A review is made of the test techniques that have been developed and used by the NACA for experimental research in aircraft structures at elevated temperatures. Some experimental results are presented. Remarks are included on the problem of model scaling for testing of structures at high temperatures. (author)

  3. 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.

  4. 5. SOUTHWEST CORNER, SHOWING WEST ELEVATION WITH BUILDING 8251 (AIRCRAFT ...

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

    5. SOUTHWEST CORNER, SHOWING WEST ELEVATION WITH BUILDING 8251 (AIRCRAFT MAINTENANCE AND REPAIR SHOPS BUILDING ADDITION) AT LEFT. - Loring Air Force Base, Arch Hangar, East of Arizona Road near southern end of runway, Limestone, Aroostook County, ME

  5. 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.

  6. Advanced composite elevator for Boeing 727 aircraft

    NASA Technical Reports Server (NTRS)

    1978-01-01

    Detail design activities are reported for a program to develop an advanced composites elevator for the Boeing 727 commercial transport. Design activities include discussion and results of the ancillary test programs, sustaining efforts, weight status, manufacturing producibility studies, quality assurance development, and production status.

  7. 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.

  8. Beamforming for aircraft noise measurements

    NASA Astrophysics Data System (ADS)

    Dougherty, Robert P.

    2003-10-01

    Phased array beamforming for aircraft noise source location has a long history, including early work on jet noise, wind tunnel measurements, and flyover testing. In the last 10 years, advancements in sparse 2-D and 3-D arrays, wind tunnel test techniques, and computer power have made phased array measurements almost common. Large aerospace companies and national research institutes have an advantage in access to major facilities and hundreds of measurement microphones, but universities and even consulting companies can perform tests with electret microphones and PC data acquisition systems. The type of testing remains a blend of science and art. A complex noise source is approximated by a mathematical model, and the microphones are deployed to evaluate the parameters of the model. For example, the simplest, but often the best, approach is to assume a distribution of mutually incoherent monopoles. This leads to an imaging process analogous to photography. Other models include coherent distributions of multipoles or duct modes. It is sometimes important to simulate the results that would have been obtained from single microphone measurements of part of the airplane in an ideal environment, had such measurements been feasible.

  9. 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.

  10. High altitude aircraft water vapor measurements.

    NASA Technical Reports Server (NTRS)

    Hilsenrath, E.

    1973-01-01

    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.

  11. 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.

  12. INVESTIGATION OF RADM PERFORMANCE USING AIRCRAFT MEASUREMENTS

    EPA Science Inventory

    Measurements using specially instrumented aircraft were obtained during August and September, 1988 as an integral part of the ACID MODES (Model Operational and Diagnostic Evaluation Study) field study. pecialized flights, each designed to diagnose different aspects of the perform...

  13. 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.

  14. 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.

  15. Elevation Measurement Profile of Mars

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The elevation measurements were collected by the Mars Orbiter Laser Altimeter (MOLA) aboard Global Surveyor during the spring and summer of 1998, as the spacecraft orbited Mars in an interim elliptical orbit. MOLA sends laser pulses toward the planet and measures the precise amount of time before the reflected signals are received back at the instrument. From this data, scientists can infer surface and cloud heights.

    During its mapping of the north polar cap, the MOLA instrument also made the first direct measurement of cloud heights on the red planet. Reflections from the atmosphere were obtained at altitudes from just above the surface to more than nine miles (approximately 15 kilometers) on about 80 percent of the laser profiles. Most clouds were observed at high latitudes, at the boundary of the ice cap and surrounding terrain.

    Clouds observed over the polar cap are likely composed of carbon dioxide that condenses out of the atmosphere during northern hemisphere winter. Many clouds exhibit dynamic structure probably caused by winds interacting with surface topography, much as occurs on Earth when winds collide with mountains to produce turbulence.

    The principal investigator for MOLA is Dr. David E. Smith of Goddard. The MOLA instrument was designed and built by the Laser Remote Sensing Branch of Laboratory for Terrestrial Physics at Goddard. The Mars Global Surveyor Mission is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for the NASA Office of Space Science.

  16. 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.

  17. 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.

  18. A Comparison of Turbulence Measurements from Aircraft.

    NASA Astrophysics Data System (ADS)

    Lemone, Margaret A.; Pennell, William T.

    1980-12-01

    A performance analysis of the three turbulence-measuring aircraft which participated in the GATE is presented. These aircraft were a Lockheed C-130 operated by the Meteorological Research Flight Centre of the U.K. Meteorological Office, a Douglas DC-6 operated by the Research Flight Facility of the National Oceanographic and Atmospheric Administration, and a Lockheed L-188 operated by the Research Aviation Facility of the National Center for Atmospheric Research.The results are based on formal intercomparison flights and analysis of fair weather days on which two or more of the aircraft were flying. In the formal intercomparison flights, two or more of the aircraft flew side by side in the fair weather atmospheric mixed layer. In both cases, the aircraft flew L-shaped patterns, consisting of 30 km legs along and normal to the mixed layer wind direction.Quantities compared include the variances of three wind components, potential temperature, moisture, and the vertical fluxes of horizontal momentum, temperature, and moisture. The analysis shows that when all components of the gust probe system are working properly, interaircraft biases are less than the expected atmospheric variability. Quirks of the three data sets are pointed out for the benefit of future GATE data users.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. Continuous measurement of aircraft wing icing

    NASA Technical Reports Server (NTRS)

    Yao, Stephen S. C.

    1994-01-01

    Ice formation on the wings of aircraft is a problem that has plagued air travel since its inception. Several recent incidents have been attributed to ice formation on the lifting surfaces of wings. This paper describes a SBIR Phase 1 research effort on the use of small flat dielectric sensors in detecting a layer of ice above the sensor. The sensors are very small, lightweight, and inexpensive. The electronics package that controls the sensor is also small, and could be even smaller using commonly available miniaturization technologies. Thus, several sensors could be placed on a surface such that a representative ice thickness profile could be measured. The benefits offered by developing this technology go beyond the safety improvements realized by monitoring ice formation on the wings of an aircraft. Continuous monitoring of anti-icing fluid concentrations on the ground would warn the pilot of impending fluid failure as well as allowing the stations to use less de-icing solution per aircraft. This in turn would increase the safety of takeoffs and reduce the overall discharge of de-icing solution into the environment, thus reducing the biohazard of the de-icing procedure.

  5. Measurement of aircraft speed and altitude

    NASA Technical Reports Server (NTRS)

    Gracey, W.

    1980-01-01

    Problems involved in measuring speed and altitude with pressure-actuated instruments (altimeter, airspeed indicator, true-airspeed indicator, Machmeter, and vertical-speed indicator) are examined. Equations relating total pressure and static pressure to the five flight quantities are presented, and criteria for the design of total and static pressure tubes are given. Calibrations of typical static pressure installations (fuselage nose, wing tip, vertical fin, and fuselage vent) are presented, various methods for flight calibration of these installations are described, and the calibration of a particular installation by two of the methods is described in detail. Equations are given for estimating the effects of pressure lag and leaks. Test procedures for the laboratory calibration of the five instruments are described, and accuracies of mechanical and electrical instruments are presented. Operational use of the altimeter for terrain clearance and vertical separation of aircraft is discussed, along with flight technical errors and overall altitude errors of aircraft in cruise operations. Altitude-measuring techniques based on a variety of properties of the Earth and the atmosphere are included. Two appendixes present airspeed and altitude tables and sample calculations for determining the various flight parameters from measured total and static pressures.

  6. Aircraft Remote Sensing Measurements of Arctic Methane

    NASA Astrophysics Data System (ADS)

    Illingworth, S. M.; Allen, G.; Gallagher, M. W.; Bower, K.; Muller, J.; O'Shea, S.; Bauguitte, S.; Vance, A.; Newman, S.; Kent, J.; Harlow, C.; Pyle, J. A.

    2013-12-01

    The importance of aircraft in-situ measurements of Arctic methane (CH4) concentrations is well understood, providing not only spatially resolved and accurate concentration data, but also essential validation for ground-based and satellite remote sensing instrumentation. The role of airborne remote sensing instruments is equally important in building up an accurate quantitative and process-driven understanding of atmospheric CH4, where the added benefit of a larger spatial coverage and potential for near surface measurements results in a better characterization of potential localized emission sources. As part of the Methane and other greenhouse gases in the Arctic - Measurements, process studies and Modelling (MAMM) campaign, the Manchester Airborne Retrieval Scheme (MARS) has been developed to produce well-characterized retrievals of atmospheric CH4 from spectra measured by the UK Met Office Airborne Research Interferometer Evaluation System (ARIES), a Fourier transform spectrometer that is mounted on the NERC Facility for Airborne Atmospheric Measurements (FAAM) aircraft. Data retrieved from ARIES spectra for methane (and other greenhouse gas) concentration profiles measured during MAMM will be presented, highlighting the utility of airborne nadir FTIR sensing for near-surface and partial-column mapping over local emission sources and in climatological sampling over wide areas. We shall demonstrate the validation of ARIES profile results against in-situ measurements, with error characterization suggesting that the retrieval bias is of the order of 1-2%. Because of the relative sensitivity to the surface when flying at low altitudes, these retrievals can be used to better characterize both the natural and industrial sources of Arctic CH4 and long-range inputs to the area, as well as being used to detect potential seabed CH4 seepage events.

  7. 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.

  8. Measuring human performance on NASA's microgravity aircraft

    NASA Technical Reports Server (NTRS)

    Morris, Randy B.; Whitmore, Mihriban

    1993-01-01

    Measuring human performance in a microgravity environment will aid in identifying the design requirements, human capabilities, safety, and productivity of future astronauts. The preliminary understanding of the microgravity effects on human performance can be achieved through evaluations conducted onboard NASA's KC-135 aircraft. These evaluations can be performed in relation to hardware performance, human-hardware interface, and hardware integration. Measuring human performance in the KC-135 simulated environment will contribute to the efforts of optimizing the human-machine interfaces for future and existing space vehicles. However, there are limitations, such as limited number of qualified subjects, unexpected hardware problems, and miscellaneous plane movements which must be taken into consideration. Examples for these evaluations, the results, and their implications are discussed in the paper.

  9. Combat aircraft noise reduction by technical measures

    NASA Astrophysics Data System (ADS)

    Wegner, M.; Kennepohl, F.; Heinig, K.

    1992-04-01

    The noise of combat aircraft during low level flight is dominated by the jet. Technical noise reduction measures must therefore reduce the specific thrust of the engine. This can be achieved by altering the engine cycle or by using secondary air to increase the mass flow though the nozzle. In the first part the influence of nozzle area, bypass ratio and variable cycle features on the specific thrust of modern fighter engines is shown. The effects on noise, thrust and fuel consumption are discussed. In the second part ejector-mixer nozzles and the aft-fan are considered. Both reduce the jet velocity by entraining air through secondary inlets and expelling it together with the engine's exhaust flow through a common nozzle.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Noise measurements of turboprop airplanes at different overflight elevations

    NASA Technical Reports Server (NTRS)

    Mueller, K.

    1990-01-01

    In order to establish criteria for the regulation of propfan aircraft engine noise emissions, measurement tests of overhead flights of a METRO-3 and a FOKKER-50 aircraft were performed. The decibel levels captured by the ground car microphone are tabulated according to the height of the microphone from the ground as the recording vehicle followed the aircraft through the test flight patterns. Microphone heights of 1.5 and 10 meters from the ground are recorded and correlated to the flight altitudes of the aircraft, which ranged from 5182-6401 meters.

  19. Calibration of infrared satellite images using high altitude aircraft measurements

    NASA Technical Reports Server (NTRS)

    Hammer, Philip D.; Gore, Warren J. Y.; Valero, Francisco P. J.

    1989-01-01

    The use of infrared radiance measurements made from high altitude aircraft for satellite image validation is discussed. Selected examples are presented to illustrate the techniques and the potentials of such validation studies.

  20. 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.

  1. Using an A-10 Aircraft for Airborne Measurements of TGFs

    NASA Astrophysics Data System (ADS)

    Fishman, G. J.; Christian, H. J.; Blakeslee, R. J.; Grove, J.; Chekhtman, A.; Jonsson, H.; Detwiler, A. G.

    2012-12-01

    Work is underway to modify an A-10 combat attack aircraft to become 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 will 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 the 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.

  2. In situ turbulence measurements from commercial aircraft

    NASA Astrophysics Data System (ADS)

    Sharman, Robert; Pearson, Julia; Meymaris, Greg; Cornman, Larry; Blackburn, Gary; Farrar, Tammy

    2013-04-01

    The statistical properties of turbulence at upper-levels in the atmosphere (upper troposphere and lower stratosphere or UTLS) are still not very well-known, partly because of the lack of adequate routine observations. This is in spite of the use that such observations would have in better quantifying dissipation rates in the atmosphere due to turbulence, but also for the practical value this information would have in alerting aircraft of potentially hazardous conditions, either in real-time or for climatological route planning. To address this, in the U.S. a program has been underway over the last few years to outfit commercial aircraft with a software package that automatically estimates and reports atmospheric turbulence intensity levels (as ɛ^1/3 where ɛ is the eddy dissipation rate) during each minute of flight. The reporting frequency is variable depending on the airline, but some reports are routinely made once per minute while others report only when the turbulence level exceeds some threshold or "trigger". The amount of turbulence data gathered is unprecedented - as of Jan 2013 there are ~ 200 aircraft outfitted with this system, contributing to well over 140 million archived records of ɛ^1/3 mostly at cruise levels of commercial aircraft, i.e., in the UTLS. In this talk the results of some statistical analyses of these ɛ^1/3 values will be presented, including vertical distributions, horizontal distributions, turbulence patch lengths and depths, and probability distribution functions (PDFs). These analyses are restricted to the U.S. for now, but as this program is expanded to international carriers, such data will begin to become available over other areas of the globe, including the North Atlantic and Europe.

  3. Aircraft measurement of organic aerosols over China.

    PubMed

    Wang, Gehui; Kawamura, Kimitaka; Hatakeyama, Shiro; Takami, Akinori; Li, Hong; Wang, Wei

    2007-05-01

    Lower to middle (0.5-3.0 km altitude) tropospheric aerosols (PM2.5) collected by aircraft over inland and east coastal China were, for the first time, characterized for organic molecular compositions to understand anthropogenic, natural, and photochemical contribution to the air quality. n-Alkanes, fatty acids, sugars, polyacids are detected as major compound classes, whereas lignin and resin products, sterols, polycyclic aromatic hydrocarbons, and phthalic acids are minor species. Average concentrations of all the identified compounds excluding malic acid correspond to 40-50% of those reported on the ground sites. Relative abundances of secondary organic aerosol (SOA) components such as malic acid are much higher in the aircraft samples, suggesting an enhanced photochemical production over China. Organic carbon (OC) concentrations in summer (average, 24.3 microg m(-3)) were equivalent to those reported on the ground sites. Higher OC/EC (elemental carbon) ratios in the summer aircraft samples also support a significant production of SOA over China. High loadings of organic aerosols in the Chinese troposphere may be responsible to an intercontinental transport of the pollutants and potential impact on the regional and global climate changes. PMID:17539513

  4. Aircraft Wake Vortex Measurement with Coherent Doppler Lidar

    NASA Astrophysics Data System (ADS)

    Wu, Songhua; Liu, Bingyi; Liu, Jintao

    2016-06-01

    Aircraft vortices are generated by the lift-producing surfaces of the aircraft. The variability of near-surface conditions can change the drop rate and cause the cell of the wake vortex to twist and contort unpredictably. The pulsed Coherent Doppler Lidar Detection and Ranging is an indispensable access to real aircraft vortices behavior which transmitting a laser beam and detecting the radiation backscattered by atmospheric aerosol particles. Experiments for Coherent Doppler Lidar measurement of aircraft wake vortices has been successfully carried out at the Beijing Capital International Airport (BCIA). In this paper, the authors discuss the Lidar system, the observation modes carried out in the measurements at BCIA and the characteristics of vortices.

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

    NASA Technical Reports Server (NTRS)

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

    1977-01-01

    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 11-19 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 were derived from the flight data and show mixing ratios predominantly between 2 and 4 microg/g with an extreme range of 1-8 microg/g. Measurement precision was estimated by comparing the simultaneously measured values from the two flight hygrometer systems. Accuracy was estimated to be about + or - 40% at 19 km. A height-averaged latitudinal cross section of water vapor indicates symmetry of wet and dry zones. This cross section is compared with other aircraft measurements and relates to meridional circulation models.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Comparison of NOAA-9 ERBE measurements with Cirrus IFO satellite and aircraft measurements

    NASA Technical Reports Server (NTRS)

    Ackerman, Steven A.; Chung, Hyosang; Cox, Stephen K.; Herman, Leroy; Smith, William L.; Wylie, Donald P.

    1990-01-01

    Earth Radiation Budget Experiment (ERBE) measurements onboard the NOAA-9 are compared for consistency with satellite and aircraft measurements made during the Cirrus Intensive Field Observation (IFO) of October 1986. ERBE scene identification is compared with NOAA-9 TIROS Operational Vertical Sounder (TOVS) cloud retrievals; results from the ERBE spectral inversion algorithms are compared with High resolution Interferometer Sounder (HIS) measurements; and ERBE radiant existance measurements are compared with aircraft radiative flux measurements.

  20. 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.

  1. Interpreting Aircraft-Derived Ice Sheet Elevation Change Using Climate Station Data

    NASA Technical Reports Server (NTRS)

    Abdalati, Waleed; Box, Jason; Steffen, Konrad

    1999-01-01

    This year repeat elevation surveys in the southern half of Greenland were made using the Airborne Topographic Mapper (ATM). The intent of these surveys is to compare present elevations to those measured in 1993 and determine the magnitude and spatial distributions of thickening and thinning rates. In order to effectively interpret any observed changes, it is important to understand the processes that affect these changes. Moreover, because the surveys are made over a brief period (2-4 weeks) during the spring or summer, it is also important to understand the effects of seasonal and interannual elevation variability, in relation to the timing of these surveys. Toward that end we are examining data from weather stations along the coast of Greenland along with data from GC-Net automatic weather stations (AWS's) on the ice sheet. The objectives are to assess: a) the importance of the timing of the flights in relation to natural processes that affect surface heights, namely accumulation and melt, and b) the temperature characteristics of the region in the five years that separated the two sets of surveys (1993-1998), in relation to the past 19 years.

  2. 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.

  3. 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.

  4. 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

    NASA Astrophysics Data System (ADS)

    Spicer, Chester W.; Holdren, Michael W.; Cowen, Kenneth A.; Joseph, Darrell W.; Satola, Jan; Goodwin, Bradley; Mayfield, Howard; Laskin, Alexander; Lizabeth Alexander, M.; Ortega, John V.; Newburn, Matthew; Kagann, Robert; Hashmonay, Ram

    Aircraft emissions affect air quality on scales from local to global. More than 20% of the jet fuel used in the U.S. is consumed by military aircraft, and emissions from this source are facing increasingly stringent environmental regulations, so improved methods for quickly and accurately determining emissions from existing and new engines are needed. This paper reports results of a study to advance the methods used for detailed characterization of military aircraft emissions, and provides emission factors for two aircraft: the F-15 fighter and the C-130 cargo plane. The measurements involved outdoor ground-level sampling downstream behind operational military aircraft. This permits rapid change-out of the aircraft so that engines can be tested quickly on operational aircraft. Measurements were made at throttle settings from idle to afterburner using a simple extractive probe in the dilute exhaust. Emission factors determined using this approach agree very well with those from the traditional method of extractive sampling at the exhaust exit. Emission factors are reported for CO 2, CO, NO, NO x, and more than 60 hazardous and/or reactive organic gases. Particle size, mass and composition also were measured and are being reported separately. Comparison of the emissions of nine hazardous air pollutants from these two engines with emissions from nine other aircraft engines is discussed.

  5. Review of measurement and testing problems. [of aircraft emissions

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Good instrumentation was required to obtain reliable and repeatable baseline data. Problems that were encountered in developing such a total system were: (1) accurate airflow measurement, (2) precise fuel flow measurement, and (3) the instrumentation used for pollutant measurement was susceptible to frequent malfunctions. Span gas quality had a significant effect on emissions test results. The Spindt method was used in the piston aircraft emissions program. The Spindt method provided a comparative computational procedure for fuel/air ratio based on measured emissions concentrations.

  6. Instrumentation for measuring aircraft noise and sonic boom

    NASA Technical Reports Server (NTRS)

    Zuckerwar, A. J. (Inventor)

    1976-01-01

    Improved instrumentation suitable for measuring aircraft noise and sonic booms is described. An electric current proportional to the sound pressure level at a condenser microphone is produced and transmitted over a cable and amplified by a zero drive amplifier. The converter consists of a local oscillator, a dual-gate field-effect transistor mixer, and a voltage regulator/impedance translator. The improvements include automatic tuning compensation against changes in static microphone capacitance and means for providing a remote electrical calibration capability.

  7. 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

  8. 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. PMID:11045531

  9. Comparison of precise ionising Radiation Dose Measurements on board Aircraft

    NASA Astrophysics Data System (ADS)

    Lindborg, L.; Beck, P.; Bottollier, J. F.; Roos, H.; Spurny, F.; Wissman, F.

    2003-04-01

    The cosmic radiation makes aircrew one of the most exposed occupational groups. The European Council has therefore in its Directive 96/29Euratom on basic safety standards for radiation protection a particular article (42) for the protection of aircrew. One of the measures to be taken is to assess the exposure of the crew. This is, however, not a trivial task. The radiation consists of many different types of radiation with energies that are hardly met on ground. The knowledge on the dose levels on board aircraft has improved gradually during the last decade as several groups around the world have performed measurements on board civil aircraft in cooperation with airlines. Only occasionally has more than one instrument been able to fly at the same time for practical reasons. The statistical uncertainty in a measurement of the dose equivalent rate is typically ±15 % (1 relative standard deviation) if determined during half an hour. Systematic uncertainties add to this. The dose rate depends on flight altitude, geographic coordinates of the flight, the phase of the solar cycle and the prevailing solar wind. For that reason the possibility to fly on the same flight will eliminate some of the systematic uncertainties that limits an evaluation of the measurement techniques. The proposal aims at measurements on board the aircraft on a geographically limited area for a few hours to decrease the statistical uncertainty of the measurements and thereby get an excellent opportunity to look for possible systematic differences between the different measurement systems. As the dose equivalent rate will be quite well established it will also be possible to compare the measured values with calculated ones. The dose rate increases towards the geomagnetic poles and decreases towards the equator. The composition of the radiation components varies also with altitude. For that reason measurements both at southern latitude and at northern latitude are planned.

  10. 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.

  11. 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.

  12. 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.

  13. Comparisons of aircraft measurements of greenhouse gases with GOSAT data

    NASA Astrophysics Data System (ADS)

    Tanaka, T.; Yates, E. L.; Iraci, L. T.; Loewenstein, M.; Gore, W.; Tadic, J.; Lopez, J. P.; Shiomi, K.; Kawakami, S.; kuze, A.; Yokota, T.

    2013-12-01

    Vertical profiles of greenhouse gases (GHGs) and ozone were measured using the Alpha Jet research aircraft as part of the Alpha Jet Atmospheric eXperiment (AJAX). Airborne instruments measuring GHGs (Picarro Inc. G2301-m) and ozone (2B Technologies Inc., model 205) are installed in a wing pod and operated from NASA Ames Research Center at Moffett Field, CA (37.415°N, 120.050°W). The in situ measurement instruments mounted on the aircraft yield precise and accurate vertical profiles of atmospheric GHGs and ozone. The purpose of this work is to validate GOSAT data and estimate from Alpha Jet measurements the contribution of GHGs from urban areas. We show the result of comparison of GOSAT and Alpha Jet measurements over Railroad Valley, NV and urban areas in Northern California. The Alpha Jet aircraft performs a measurement over the Railroad Valley (RRV) desert playa, Nevada (38.497°N, 115.691°W, 1437m above mean sea level) once a month for the comparison with Greenhouse gases Observing Satellite (GOSAT) measurements from 2011. The GOSAT was developed to measure concentrations of CO2 and CH4 from space and has been in operation from 2009. The instruments onboard GOSAT are the Thermal And Near-infrared Sensor for carbon Observation Fourier Transform Spectrometer (TANSO-FTS) and the TANSO Cloud and Aerosol Imager (TANSO-CAI) (Kuze et al., 2009). The RRV playa is a flat, high altitude desert site and an area where local sources and sinks of carbon-species are expected to be minimal. The playa has virtually no vegetation and an overall size of 15 km× 15 km, which includes GOSAT's field of view. Reference Akihiko Kuze, Hiroshi Suto, Masakatsu Nakajima, and Takashi Hamazaki. Thermal and near infrared sensor for carbon observation Fourier-transform spectrometer on the Greenhouse Gases Observing Satellite for greenhouse gases monitoring. App. Opt., 48, 6716-6733, 2009.

  14. 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.

  15. 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.

  16. Solar Radiation Measurements Onboard the Research Aircraft HALO

    NASA Astrophysics Data System (ADS)

    Lohse, I.; Bohn, B.; Werner, F.; Ehrlich, A.; Wendisch, M.

    2014-12-01

    Airborne measurements of the separated upward and downward components of solar spectral actinic flux densities for the determination of photolysis frequencies and of upward nadir spectral radiance were performed with the HALO Solar Radiation (HALO-SR) instrument package onboard the High Altitude and Long Range Research Aircraft (HALO). The instrumentation of HALO-SR is characterized and first measurement data from the Next-generation Aircraft Remote-Sensing for Validation Studies (NARVAL) campaigns in 2013 and 2014 are presented. The measured data are analyzed in the context of the retrieved microphysical and optical properties of clouds which were observed underneath the aircraft. Detailed angular sensitivities of the two optical actinic flux receivers were determined in the laboratory. The effects of deviations from the ideal response are investigated using radiative transfer calculations of atmospheric radiance distributions under various atmospheric conditions and different ground albedos. Corresponding correction factors are derived. Example photolysis frequencies are presented, which were sampled in the free troposphere and lower stratosphere over the Atlantic Ocean during the 2013/14 HALO NARVAL campaigns. Dependencies of photolysis frequencies on cloud cover, flight altitude and wavelength range of the photolysis process are investigated. Calculated actinic flux densities in the presence of clouds benefit from the measured spectral radiances. Retrieved cloud optical thicknesses and effective droplet radii are used as model input for the radiative transfer calculations. By comparison with the concurrent measurements of actinic flux densities the retrieval approach is validated. Acknowledgements: Funding by the Deutsche Forschungsgemeinschaft within the priority program HALO (BO 1580/4-1, WE 1900/21-1) is gratefully acknowledged.

  17. ELEVATION LOOKING NORTH OF MAIN ENTRANCE WITH MEASURING STICK ...

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

    ELEVATION LOOKING NORTH OF MAIN ENTRANCE WITH MEASURING STICK - New York State Soldiers & Sailors Home, Building No. 78, Department of Veterans Affairs Medical Center, 76 Veterans Avenue, Bath, Steuben County, NY

  18. ELEVATION OF ENTRANCE AND PORCH WITH MEASURING STICK New ...

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

    ELEVATION OF ENTRANCE AND PORCH WITH MEASURING STICK - New York State Soldiers & Sailors Home, Building No. 52, Department of Veterans Affairs Medical Center, 76 Veterans Avenue, Bath, Steuben County, NY

  19. ELEVATION OF SOUTH FACADE LOOKING NORTH WITH MEASURING STICK ...

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

    ELEVATION OF SOUTH FACADE LOOKING NORTH WITH MEASURING STICK - New York State Soldiers & Sailors Home, Building No. 29, Department of Veterans Affairs Medical Center, 76 Veterans Avenue, Bath, Steuben County, NY

  20. 20. Photocopy of 1897 measured drawing showing elevations and plans ...

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

    20. Photocopy of 1897 measured drawing showing elevations and plans of Soliture. Delineators: Charles L. Hillman and John McClintock. Original at the Free Library of Philadelphia, Philadelphia, Pa. - Solitude, Zoo grounds, Philadelphia, Philadelphia County, PA

  1. 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

  2. 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

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. Aircraft exterior scratch measurement system using machine vision

    NASA Astrophysics Data System (ADS)

    Sarr, Dennis P.

    1991-08-01

    In assuring the quality of aircraft skin, it must be free of surface imperfections and structural defects. Manual inspection methods involve mechanical and optical technologies. Machine vision instrumentation can be automated for increasing the inspection rate and repeatability of measurement. As shown by previous industry experience, machine vision instrumentation methods are not calibrated and certified as easily as mechanical devices. The defect must be accurately measured and documented via a printout for engineering evaluation and disposition. In the actual usage of the instrument for inspection, the device must be portable for factory usage, on the flight line, or on an aircraft anywhere in the world. The instrumentation must be inexpensive and operable by a mechanic/technician level of training. The instrument design requirements are extensive, requiring a multidisciplinary approach for the research and development. This paper presents the image analysis results of microscopic structures laser images of scratches on various surfaces. Also discussed are the hardware and algorithms used for the microscopic structures laser images. Dedicated hardware and embedded software for implementing the image acquisition and analysis have been developed. The human interface, human vision is used for determining which image should be processed. Once the image is chosen for analysis, the final answer is a numerical value of the scratch depth. The result is an answer that is reliable and repeatable. The prototype has been built and demonstrated to Boeing Commercial Airplanes Group factory Quality Assurance and flight test management with favorable response.

  8. 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.

  9. 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.

  10. Remote measurement of the plume shape of aircraft exhausts at airports by passive FTIR spectrometry

    NASA Astrophysics Data System (ADS)

    Schafer, Klaus; Jahn, Carsten; Utzig, Selina; Flores-Jardines, Edgar; Harig, Roland; Rusch, Peter

    2004-11-01

    Information about the interaction between the exhaust plume of an aircraft jet engine and ambient air is required for the application of small-scale chemistry-transport models to investigate airport air quality. This interaction is not well understood. In order to study the interaction, spatial information about the plume is required. FTIR emission spectroscopy may be applied to analyze the aircraft exhausts. In order to characterize the plumes spatially, a scanning imaging FTIR system (SIGIS) has been improved. SIGIS is comprised of an interferometer (Bruker OPAG), an azimuth-elevation-scanning mirror, a data acquisition and control system with digital signal processors (DSP), an infrared camera and a personal computer. With this instrumentation it is possible to visualise the plume and to obtain information about the temperature distribution within the plume. Measurements are performed at low spectral resolution, because the dynamic environment of these measurements limits the measurement time to about 2 minutes. Measurements of the plume shapes of an APU and of main engines were performed.

  11. The emittance of space radiator materials measured at elevated temperatures

    SciTech Connect

    Mirtich, M.J.; DiFilippo, F.; Barry, J.; Kussmaul, M.

    1994-09-01

    The spectral emittances of textured space radiator materials between 1.7 and 14.7 {mu}m have been evaluated at room temperature and elevated temperature (630{degrees}C) in air. Heating in air caused a permanent increase in spectral emittance for all materials tested: HCl/ion beam textured 304 stainless steel, untextured Ti (6 percent Al, 4 percent V), and sandblasted Ti (6 percent Al, 4 percent V). Changes in the surface chemistry and/or surface morphology of these materials were also observed. Elevated temperature spectral emittance was measured in an argon atmosphere and compared to the measurements in air. Similarity between the room temperature and elevated temperature spectral emittance measurements was also investigated, and limited agreement was found.

  12. 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.

  13. Determination of Elevator and Rudder Hinge Forces on the Learjet Model 55 Aircraft

    NASA Technical Reports Server (NTRS)

    Boroughs, R. R.; Padmanabhan, V.

    1983-01-01

    The empennage structure on the Learjet 55 aircraft was quite similar to the empennage structure on earlier Learjet models. However, due to an important structural change in the vertical fin along with the new loads environment on the 50 series aircraft, a structural test was required on the vertical fin, but the horizontal tail was substantiated by a comparative analysis with previous tests. NASTRAN analysis was used to investigate empennage deflections, stress levels, and control surface hinge forces. The hinge force calculations were made with the control surfaces in the deflected as well as undeflected configurations. A skin panel buckling analysis was also performed, and the non-linear effects of buckling were simulated in the NASTRAN model to more accurately define internal loads and stress levels. Comparisons were then made between the Model 55 and the Model 35/36 stresses and internal forces to determine which components were qualified by previous tests. Some of the methods and techniques used in this analysis are described.

  14. 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.

  15. 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.

  16. 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

  17. Instrumentation for measurement of aircraft noise and sonic boom

    NASA Technical Reports Server (NTRS)

    Zuckerwar, A. J. (Inventor)

    1975-01-01

    A jet aircraft noise and sonic boom measuring device which converts sound pressure into electric current is described. An electric current proportional to the sound pressure level at a condenser microphone is produced and transmitted over a cable, amplified by a zero drive amplifier and recorded on magnetic tape. The converter is comprised of a local oscillator, a dual-gate field-effect transistor (FET) mixer and a voltage regulator/impedance translator. A carrier voltage that is applied to one of the gates of the FET mixer is generated by the local oscillator. The microphone signal is mixed with the carrier to produce an electrical current at the frequency of vibration of the microphone diaphragm by the FET mixer. The voltage of the local oscillator and mixer stages is regulated, the carrier at the output is eliminated, and a low output impedance at the cable terminals is provided by the voltage regulator/impedance translator.

  18. 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

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

    PubMed

    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

  20. 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.

  1. 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.

  2. 4. Photocopy of measured drawing dated January, 1948 FRONT ELEVATION ...

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

    4. Photocopy of measured drawing dated January, 1948 FRONT ELEVATION An addendum to Hanson-Cramer House, Sea Street, south end, Rockport, Knox County, Maine - Hanson-Cramer House, End of Sea Street (moved from Pascal's Avenue), Rockport, Knox County, ME

  3. 5. Photocopy of measured drawing dated January, 1946 ELEVATIONS (EXISTING) ...

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

    5. Photocopy of measured drawing dated January, 1946 ELEVATIONS (EXISTING) An addendum to Hanson-Cramer House, Sea Street, south end, Rockport, Knox County, Maine - Hanson-Cramer House, End of Sea Street (moved from Pascal's Avenue), Rockport, Knox County, ME

  4. 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

  5. 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

  6. 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.

  7. 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.

  8. 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.

    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 degradation in lift and drag.

  9. Ice sheet surface elevation retrieval from CALIPSO lidar measurements

    NASA Astrophysics Data System (ADS)

    Lu, Xiaomei; Hu, Yongxiang

    2013-05-01

    The primary objective of the atmospheric profiling lidar aboard Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission launched in April 2006 has been studying the climate impact of clouds and aerosols in the atmosphere. However, CALIPSO lidar also collects information about other components of the Earth's ecosystem, such as polar ice sheets. The purpose of this study is to propose a new technique to provide high resolution of polar ice sheet surface elevation from CALIPSO single shot lidar measurements (70 m spot size). The new technique relies on an empirical relationship between the peak signal ratio and the distance between the surface and the peak signal range bin center to achieve high altimetry resolution. The ice sheet surface elevation results in the region of Greenland and Antarctic compare very well with the Ice, Cloud and land Elevation Satellite (ICESat) laser altimetry measurements. The comparisons suggest that the obtained CALIPSO ice sheet surface elevation by the new technique is accurate to within 1 m. Based on the new technique, the preliminary data product of along-track topography retrieved from the CALIPSO lidar measurements is available to the altimetry community for evaluation.

  10. Holistic aerosol evaluation using synthesized aerosol aircraft measurements

    NASA Astrophysics Data System (ADS)

    Watson-Parris, Duncan; Reddington, Carly; Schutgens, Nick; Stier, Philip; Carslaw, Ken; Liu, Dantong; Allan, James; Coe, Hugh

    2016-04-01

    Despite ongoing efforts there are still large uncertainties in aerosol concentrations and loadings across many commonly used GCMs. This in turn leads to large uncertainties in the contributions of the direct and indirect aerosol forcing on climate. However, constraining these fields using earth observation data, although providing global coverage, is problematic for many reasons, including the large uncertainties in retrieving aerosol loadings. Additionally, the inability to retrieve aerosols in or around cloudy scenes leads to further sampling biases (Gryspeerdt 2015). Many in-situ studies have used regional datasets to attempt to evaluate the model uncertainties, but these are unable to provide an assessment of the models ability to represent aerosols properties on a global scale. Within the Global Aerosol Synthesis and Science Project (GASSP) we have assembled the largest collection of quality controlled, in-situ aircraft observations ever synthesized to a consistent format. This provides a global set of in-situ measurements of Cloud Condensation Nuclei (CCN) and Black Carbon (BC), amongst others. In particular, the large number of vertical profiles provided by this aircraft data allows us to investigate the vertical structure of aerosols across a wide range of regions and environments. These vertical distributions are particularly valuable when investigating the dominant processes above or below clouds where remote sensing data is not available. Here we present initial process-based assessments of the BC lifetimes and vertical distributions of CCN in the HadGEM-UKCA and ECHAM-HAM models using this data. We use point-by-point based comparisons to avoid the sampling issues associated with comparing spatio-temporal aggregations.

  11. 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.

  12. 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

  13. 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.

  14. 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.

  15. 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.

  16. 14 CFR Appendix A to Part 36 - Aircraft Noise Measurement and Evaluation Under § 36.101

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 1 2013-01-01 2013-01-01 false Aircraft Noise Measurement and Evaluation Under § 36.101 A Appendix A to Part 36 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT NOISE STANDARDS: AIRCRAFT TYPE AND AIRWORTHINESS CERTIFICATION Pt. 36, App. A Appendix A to Part 36—Aircraft...

  17. 14 CFR Appendix A to Part 36 - Aircraft Noise Measurement and Evaluation Under § 36.101

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 1 2011-01-01 2011-01-01 false Aircraft Noise Measurement and Evaluation Under § 36.101 A Appendix A to Part 36 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT NOISE STANDARDS: AIRCRAFT TYPE AND AIRWORTHINESS CERTIFICATION Pt. 36, App. A Appendix A to Part 36—Aircraft...

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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

  3. 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.

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

    PubMed

    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

  5. 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

  6. 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.

  7. Measurement, analysis, and prediction of aircraft interior noise

    NASA Technical Reports Server (NTRS)

    Howlett, J. T.; Williams, L. H.; Catherines, J. J.; Jha, S. K.

    1976-01-01

    Considerations of comfort of passengers and crew in light aircraft and helicopters indicate substantial benefits may be obtained by the reduction of interior noise levels. This paper discusses an ongoing research effort to reduce interior noise in such vehicles. Data from both field and laboratory studies for a light aircraft are presented. The laboratory data indicate that structural vibration is an efficient source of interior noise and should be considered in the reduction of interior noise. Flight data taken on a helicopter before and after installation of acoustic treatment demonstrate that over 30 dB of noise reduction can be obtained in certain portions of the spectra. However, subjective evaluations of the treated vehicle indicate that further reductions in interior noise are desirable. An existing interior noise prediction method which was developed for large jet transports was applied to study low-frequency noise in a light aircraft fuselage. The results indicate that improvements in the analytical model may be necessary for the prediction of interior noise of light aircraft.

  8. Measures of pilot performance during V/TOL aircraft landings on ships at sea

    NASA Technical Reports Server (NTRS)

    Howard, J. C.

    1977-01-01

    Simulation experiments to determine the feasibility of landing V/TOL aircraft on ships at sea were studied. The motion and attitude of the aircraft relative to the landing platform was known at the instant of touchdown. The success of these experiments depended on the ability of the experimenter to measure the pilot's performance during the landing maneuver. To facilitate these measurements, the equations describing the motion of the aircraft and its attitude relative to the landing platform are presented in a form which is suitable for simulation purposes.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. Measurements made aloft by a twin-engine aircraft to support the SCOS97-NARSTO study. Final report

    SciTech Connect

    Anderson, J.A.; Blumenthal, D.L.

    1999-05-01

    During the summer of 1997, the Southern California Ozone Study (SCOS97) was conducted to update aerometric and emissions databases and model applications for ozone episodes in southern California and to quantify the contributions of interbasin transport to exceedances of the ozone standards in neighboring air basins. One of six SCOS97 sampling aircraft was a Piper Aztec. The Aztec performed northern-boundary measurements of aloft air quality and meteorology in the southern Mojave Desert and northern Los Angeles basin. The aircraft also served as a backup for another SCOS97 aircraft that performed flights in the western part of the study domain. The Aztec data were reviewed to identify the occurrence and types of ozone layers aloft and to estimate the initial and boundary conditions in the Desert on the first day of Intensive Operational Periods (IOPs). Ozone carryover aloft was seen on all mornings in vertical spiral measurements in the Basin. Detached layers above the boundary layer were seen on about 20% of Basin morning and afternoon spirals. Offshore elevated ozone layers of up to 184 ppb were seen below 500 m. The morning ozone concentrations in the Desert ranged from 40 to 70 ppb and the Noy concentrations ranged from 2 to 4 ppb, indicating relatively clean, but not pristine boundary conditions.

  14. 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.

  15. RF radiation from lightning correlated with aircraft measurements during storm hazards-82

    NASA Technical Reports Server (NTRS)

    Levine, D. M.

    1983-01-01

    During the Storm Hazards Experiment 1982, the Goddard Space Flight Center monitored radiation from lightning from a site at the Wallops Flight Facility, Wallops Island, VA. Measurements were made while the NASA F106 penetrated thunderstorms to obtain data on lightning strikes to the aircraft. The objective of the ground-based measurements was to help determine if the events recorded by the F106 were part of lightning discharges. During the experiment, 53 cases were obtained in which events were recorded aboard the aircraft while reliable quality RF radiation was recorded on the ground. These cases came from 12 different storms occurring from June through August 1982. The data confirms that the aircraft was measuring events which were part of lightning and indicates that the events recorded on the aircraft tend to occur early in the flash.

  16. Radiation measurements aboard nasa ER-2 high altitude aircraft with the liulin-4J portable spectrometer

    NASA Astrophysics Data System (ADS)

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

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

  17. 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.

  18. 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.

  19. Nordic Standards for measurement of aircraft noise immission in residential areas and noise reduction of dwellings

    NASA Astrophysics Data System (ADS)

    Svane, Christian; Plovsing, Birger

    Quantification by measurement of aircraft noise in residential areas and air traffic noise reduction of dwellings suffer from sensibility to the measurement technique used. Around the Copenhagen Airport (200.000 opr./year) 3.500 families have been granted from 50% to 90% of sound insulation costs by the Danish Government. Based on experience from evaluation measurements carried out by the Danish Acoustical Institute, the authors have proposed standardized measurement methods for the outdoor aircraft noise in residential areas and for the noise reduction of dwellings. In 1989 both noise measurement methods were accepted as Nordic Standards (NORDTEST ACOU 074 and 075) by Denmark, Finland, Iceland, Norway and Sweden.

  20. Inefficiency of sanitation measures aboard commercial aircraft: environmental pollution and disease.

    PubMed

    Kikuchi, R

    1977-07-01

    Recent investigations at Tokyo International Airport have proven that environmental pollution resulting from the inefficient disposal of human excretion aboard aircraft is an important problem from the standpoint of quarantine. It is, therefore, recommended that the worldwide aviation industry take immediate measures to improve conditions and eliminate this problem, which has thus far been ignored by aircraft designers, airport administration, and CAB personnel. PMID:329830

  1. 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.

    1985-01-01

    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.

  2. 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.

  3. Aircraft measurements of the impacts of pollution aerosols on clouds and precipitation over the Sierra Nevada

    NASA Astrophysics Data System (ADS)

    Rosenfeld, Daniel; Woodley, William L.; Axisa, Duncan; Freud, Eyal; Hudson, James G.; Givati, Amir

    2008-08-01

    Recent publications suggest that anthropogenic aerosols suppress orographic precipitation in California and elsewhere. A field campaign (SUPRECIP: Suppression of Precipitation) was conducted to investigate this hypothesized aerosol effect. The campaign consisted of in situ aircraft measurements of the polluting aerosols, the composition of the clouds ingesting them, and the way the precipitation-forming processes are affected. SUPRECIP was conducted during February and March of 2005 and February and March of 2006. The flights documented the aerosols and orographic clouds flowing into the central Sierra Nevada from the upwind densely populated industrialized/urbanized areas and contrasted them with the aerosols and clouds downwind of the sparsely populated areas in the northern Sierra Nevada. SUPRECIP found that the aerosols transported from the coastal regions are augmented greatly by local sources in the Central Valley resulting in high concentrations of aerosols in the eastern parts of the Central Valley and the Sierra foothills. This pattern is consistent with the detected patterns of suppressed orographic precipitation, occurring primarily in the southern and central Sierra Nevada, but not in the north. The precipitation suppression occurs mainly in the orographic clouds that are triggered from the boundary layer over the foothills and propagate over the mountains. The elevated orographic clouds that form at the crest are minimally affected. The clouds are affected mainly during the second half of the day and the subsequent evening, when solar heating mixes the boundary layer up to cloud bases. Local, yet unidentified nonurban sources are suspected to play a major role.

  4. Aircraft measurements of trace gases between Japan and Singapore in October of 1993, 1996, and 1997

    NASA Astrophysics Data System (ADS)

    Matsueda, Hidekazu; Inoue, Hisayuki Y.

    Carbon dioxide (CO2), methane (CH4), and carbon monoxide (CO) mixing ratios were measured in discrete air samples from aircraft between Japan and Singapore in October. The mixing ratios of all trace gases at 9-12 km were enhanced over the South China Sea in 1997 compared with those in 1993 and 1996. Vertical distributions of all trace gases over Singapore in 1997 also showed largely elevated mixing ratios at all altitudes. These distributions indicate a wide outflow of trace gases from intense biomass burning in the southeast Asia regions in the very strong El Niño year. The enhanced trace gases showed a strong linear correlation between CH4 and CO, and between CO and CO2, with the regression slopes of 0.051 (ΔCH4 ppb/ΔCOppb) and 0.089 (ΔCOppb/ΔCO2ppb). The emission ratios are characteristic of fires with relatively lower combustion efficiency from the tropical rain forest and peat lands in Kalimantan and Sumatra of Indonesia.

  5. 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.

  6. Response properties of atmospheric turbulence measurement instruments using Russian research aircraft

    NASA Astrophysics Data System (ADS)

    Strunin, M. A.; Hiyama, T.

    2004-11-01

    Instruments that measure atmospheric turbulence for the estimation of turbulent fluxes of heat, water vapor, and carbon dioxide were tested in the laboratory and during in-flight conditions aboard a Russian research Ilyushin-18 aircraft. The response characteristics of the aircraft turbulence sensors were first tested to decrease measurement errors for turbulent heat transfer and fluxes, including water vapour flux, before being installed on the Ilyushin-18 aircraft that was used in joint Russian-Japanese atmospheric boundary-layer research. The results show that the atmospheric turbulence measured in a frequency range of 0.01 to 10 Hz yielded proper estimates of fluxes. Errors in measurements of the turbulence made from the aircraft were also analysed. Aerodynamic distortions linked to the aircraft's body and propellers were determined from flight test experiments. Time lags between vertical wind speed fluctuations and air temperature fluctuations measured by the aircraft thermometer, and those between vertical wind speed fluctuations and air humidity fluctuations measured by an ultraviolet hygrometer (open-path system) and an infrared hygrometer (closed-path system) were estimated. The vertical wind speed and air temperature sensor measurements showed no time lag, but a time lag of 0.6 s occurred between vertical wind speed and ultraviolet hygrometer measurements. The time lag between vertical wind speed and the infrared hygrometer measurements depended on flight conditions due to air pumping load, and had to be defined for each sampling leg. Accounting for the time lag was critical for water vapour flux measurements and helped to eliminate large systematic errors.

  7. A measurement model for general noise reaction in response to aircraft noise.

    PubMed

    Kroesen, Maarten; Schreckenberg, Dirk

    2011-01-01

    In this paper a measurement model for general noise reaction (GNR) in response to aircraft noise is developed to assess the performance of aircraft noise annoyance and a direct measure of general reaction as indicators of this concept. For this purpose GNR is conceptualized as a superordinate latent construct underlying particular manifestations. This conceptualization is empirically tested through estimation of a second-order factor model. Data from a community survey at Frankfurt Airport are used for this purpose (N=2206). The data fit the hypothesized factor structure well and support the conceptualization of GNR as a superordinate construct. It is concluded that noise annoyance and a direct measure of general reaction to noise capture a large part of the negative feelings and emotions in response to aircraft noise but are unable to capture all relevant variance. The paper concludes with recommendations for the valid measurement of community reaction and several directions for further research. PMID:21303002

  8. 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.

  9. Measurement and analysis of aircraft and vehicle LRCS in outfield test

    NASA Astrophysics Data System (ADS)

    Cao, Chang-Qing; Zeng, Xiao-dong; Fan, Zhao-jin; Feng, Zhe-jun; Lai, Zhi

    2015-04-01

    The measurement of aircraft and vehicle Laser Radar Cross Section (LRCS) is of crucial importance for the detection system evaluation and the characteristic research of the laser scattering. A brief introduction of the measuring theory of the laser scattering from the full-scale aircraft and vehicle targets is presented in this paper. By analyzing the measuring condition in outfield test, the laser systems and test steps are designed for full-scale aircraft and vehicle LRCS and verified by the experiment in laboratory. The processing data error 7% below is obtained of the laser radar cross section by using Gaussian compensation and elimination of sky background for original test data. The study of measurement and analysis proves that the proposed method is effective and correct to get laser radar cross section data in outfield test. The objectives of this study were: (1) to develop structural concepts for different LRCS fuselage configurations constructed of conventional materials; (2) to compare these findings with those of aircrafts or vehicles; (3) to assess the application of advanced materials for each configuration; (4) to conduct an analytical investigation of the aerodynamic loads, vertical drag and mission performance of different LRCS configurations; and (5) to compare these findings with those of the aircrafts or vehicles.

  10. 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.

  11. Two-frequency microwave resonance measurements from an aircraft - A quantitative estimate of the directional ocean surface spectrum

    NASA Technical Reports Server (NTRS)

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

    1984-01-01

    The use of the two-frequency microwave-resonance technique for airborne measurements of ocean surface-wave spectral components is examined in a summary of experiments conducted with a coherent Ku-band radar flown on a P-3 aircraft in the 1979 MARSEN and 1980 ARSLOE projects. The 1D theoretical formulation used in the analysis of the MARSEN data by Johnson et al. (1982) is extended to the 2D case; the experimental conditions are described in detail; and typical data are presented graphically, analyzed, and compared with independent measurements obtained with a surface-contour radar. The 3.5-deg pencil-beam configuration used in ARSLOE is shown to produce spectra with good directional characteristics (strong resonances at angles of incidence 13-48 deg). It is found that the proper inversion of radar data to surface-elevation spectra requires surface-reflectivity-modulation sources in addition to the long-wave orbital velocity.

  12. 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

  13. 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

  14. Carrier phase delay altimetry from low eleveation GPSR measurements

    NASA Technical Reports Server (NTRS)

    Cardellach, E.; Treuhaft, R.; Franklin, G.; Gorelik, J.; Lowe, S. T.; Young, L. E.

    2003-01-01

    GPS-Reflections (GPSR) observations at very low elevation angles take advantage of the apparent smoothness of the surface to enable phase-delay altimetry, of centimetric nominal precision, higher than the GPSR code-delay estimates.

  15. Pose measurement base on machine vision for the aircraft model in wire-driven parallel suspension system

    NASA Astrophysics Data System (ADS)

    Chen, Yi-feng; Wu, Liao-ni; Yue, Sui-lu; Lin, Qi

    2013-03-01

    In wind tunnel tests, the pose of the aircraft model in wire-driven parallel suspension system (WDPSS) is determined by driving several wires. Pose measurement is very important for the study of WDPSS. Using machine vision technology, Monocular Vision Measurement System has been constructed to estimate the pose of the aircraft model by applying a camera calibration, by extracting corresponding control points for the aircraft model, and by applying several homogeneous transformations. This article describes the programs of the measurement system, measurement principle and data processing methods which is based on HALCON to achieve the Solution of the pose of aircraft model. Through experiments, practical feasibility of the system is validated.

  16. Measuring the 3-D wind vector with a weight-shift microlight aircraft

    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. Therefore 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.

  17. Estimation of aircraft wake vortex parameters from data measured by a Stream Line lidar

    NASA Astrophysics Data System (ADS)

    Smalikho, I. N.; Banakh, V. A.

    2015-11-01

    A method for estimation of aircraft wake vortex parameters (coordinates of axis and circulation of vortices) from raw data measured by a pulsed coherent Doppler lidar "Stream Line" has been offered. By numerical simulation we found optimal measurement parameters, with which it is possible to obtain information about the wake vortices, despite the low level of echo signal inherent to this lidar. The method was tested in an experiment at the airfield of Tomsk airport. The results of the experimental data processing are consistent with theoretical calculations for the type of aircrafts involved in this experiment.

  18. 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.

  19. 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.

  20. Visualization of gust gradients and aircraft response as measured by the NASA B-57B aircraft

    NASA Technical Reports Server (NTRS)

    Camp, D.; Campbell, W.; Dow, C.; Phillips, M.; Gregory, R.; Frost, W.

    1984-01-01

    A program to obtain gust gradient measurements over the span of an airfoil is being conducted by NASA. Data have been collected from four areas of the United States (Denver, Colorado; Edwards, California; Huntsville, Alabama; and Norman, Oklahoma). The background program development data collection, and some data analysis efforts of the gust gradient effort have previously been presented (Houbolt, 1979; Camp, et al., 1983; Campbell, 1983; Campbell, et al., 1983; Frost, et al., 1983; and Painter and Camp, 1983). The purpose of this paper is to discuss briefly the animation of a gust gradient data set that was collected during the summer of 1982 at Denver, Colorado.

  1. Short-term variation of cosmic radiation measured by aircraft under constant flight conditions

    NASA Astrophysics Data System (ADS)

    Lee, Jaejin; Nam, Uk-Won; Pyo, Jeonghyun; Kim, Sunghwan; Kwon, Yong-Jun; Lee, Jaewon; Park, Inchun; Kim, Myung-Hee Y.; Dachev, Tsventan P.

    2015-11-01

    The temporal variations in cosmic radiation on aircraft under constant flight conditions were measured by a Liulin detector. Rather than a commercial long-distance aircraft, we used a military reconnaissance aircraft performing a circular flight at a constant altitude over the Korean Peninsula. At 9144 m (30,000 ft), the mean and standard deviation of the radiation dose rate (among 35 measurements) was 2.3 and 0.17 μSv/h, respectively. The experiment yielded two observational results. First, the dose rate changed over a flight time of 5-7 h; second, no strong correlation was revealed between the cosmic rays observed from the ground-based neutron monitor and the radiation doses at aircraft altitude. These observations can provide insight into the short-term variation of cosmic radiation at aviation altitudes. When discarding various negligible factors, it is postulated that the changes in the geomagnetic field and the air density still could affect the variation of cosmic radiation at aircraft altitude. However, various factors are less known about the dependence on the cosmic radiation. Therefore, investigations of possible factors are also warranted at the monitoring points of space weather.

  2. 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.

  3. 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

  4. Probing Emissions of Military Cargo Aircraft: Description of a Joint Field Measurement Program

    SciTech Connect

    Cheng, Mengdawn; Corporan, E.; DeWitt, M.; Spicer, C.; Holdren, M.; Cowen, K.; Harris, B.; Shores, R.; Hashmonay, R.; Kaganan, R.

    2008-01-01

    Direct emissions of NOx, volatile organic compounds, and particulate matter (PM) by aircraft contribute to the pollutant levels found in the atmosphere. Aircraft emissions can be injected at the ground level or directly at the high altitude in flight. Conversion of the precursor gases into secondary PM is one of the pathways for the increased atmospheric PM. Atmospheric PM interacts with solar radiation altering atmospheric radiation balance and potentially contributing to global and regional climate changes. Also, direct emissions of air toxics, ozone precursors and PM from aircraft in and around civilian airports and military air bases can worsen local air quality in non-attainment and/or maintenance areas. These emissions need to be quantified. However, the current EPA methods for particle emission measurements from such sources, modified Method 5 and Conditional Test Method 039, are gravimetric-based, and it is anticipated that these methods will not be suitable for current and future generations of aircraft turbine engines, whose particle mass emissions are low. To evaluate measurement approaches for military aircraft emissions, two complementary projects were initiated in 2005. A joint field campaign between these two programs was executed during the first week of October 2005 at the Kentucky Air National Guard (KYANG) base in Louisville, KY. This campaign represented the first in a series of field studies for each program funded by the DoD Strategic Environmental Research and Development Program (SERDP) and provided the basis for cross-comparison of the sampling approaches and measurement techniques employed by the respective program teams. This paper describes the overall programmatic of the multi-year SERDP aircraft emissions research and presents a summary of the results from the joint field campaign.

  5. Status of NASA aircraft engine emission reduction and upper atmosphere measurement programs

    NASA Technical Reports Server (NTRS)

    Rudey, R. A.; Lezberg, E. A.

    1976-01-01

    Advanced emission reduction techniques for five existing aircraft gas turbine engines are evaluated. Progress made toward meeting the 1979 EPA standards in rig tests of combustors for the five engines is reported. Results of fundamental combustion studies suggest the possibility of a new generation of jet engine combustor technology that would reduce oxides-of-nitrogen (NOx) emissions far below levels currently demonstrated in the engine-related programs. The Global Air Sampling Program (GAS) is now in full operation and is providing data on constituent measurements of ozone and other minor upper-atmosphere species related to aircraft emissions.

  6. 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.

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

    Atmospheric Science Data Center

    2016-06-13

    MISR Browse Images: Chesapeake Lighthouse and Aircraft Measurements for Satellites (CLAMS)   These MISR Browse images provide a quick visual overview of the region observed during the ... is found at the  CLAMS home page . The MISR Browse images from the nadir camera include paths 13, 14, and 15 for July 10 to August ...

  8. 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.

  9. 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.

  10. 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.

  11. Output tracking control for a velocity-sensorless VTOL aircraft with measurement delays

    NASA Astrophysics Data System (ADS)

    Su, Shanwei; Lin, Yan

    2015-04-01

    In this paper, we develop a non-linear controller to achieve output tracking for a velocity-sensorless vertical take-off and landing (VTOL) aircraft in the presence of measurement delays. By applying the Pade approximation technique, the original controlled system is transformed into an augmented dimension system without any time delay. After constructing full-order observers, error coordinate transformation, and system decomposition, the tracking problem of the newly transformed system is changed into the stabilisation problem of two non-minimum phase subsystems and one minimum phase subsystem. The resulting controller not only forces the VTOL aircraft to asymptotically track the desired trajectories, but also drives the unstable internal dynamics, which stands for the non-minimum property of VTOL aircraft, to follow the causal ideal internal dynamics (IID) solved via the stable system centre (SSC) method. Numerical simulation results illustrate the effectiveness of the proposed controller.

  12. Measuring the 3-D wind vector with a weight-shift microlight aircraft

    NASA Astrophysics Data System (ADS)

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

    2011-02-01

    This study investigates whether the 3-D wind vector can be measured reliably from a highly transportable and low-cost weight-shift microlight aircraft. Therefore 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 aeroelastic wing (53%), as well as sudden changes in wing loading (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 deviation) 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.

  13. Directional acoustic measurements by laser Doppler velocimeters. [for jet aircraft noise

    NASA Technical Reports Server (NTRS)

    Mazumder, M. K.; Overbey, R. L.; Testerman, M. K.

    1976-01-01

    Laser Doppler velocimeters (LDVs) were used as velocity microphones to measure sound pressure level in the range of 90-130 db, spectral components, and two-point cross correlation functions for acoustic noise source identification. Close agreement between LDV and microphone data is observed. It was concluded that directional sensitivity and the ability to measure remotely make LDVs useful tools for acoustic measurement where placement of any physical probe is difficult or undesirable, as in the diagnosis of jet aircraft noise.

  14. Triple Oxygen Isotope Measurement of Nitrate to Analyze Impact of Aircraft Emissions

    NASA Astrophysics Data System (ADS)

    Chan, Sharleen

    With 4.9% of total anthropogenic radiative forcing attributed to aircraft emissions, jet engines combust copious amounts of fuel producing gases including: NOx (NO + NO2), SOx, VOC's and fine particles [IPCC (1999), IPCC (2007), Lee et al., 2009]. The tropospheric non-linear relationships between NOx, OH and O3 contribute uncertainties in the ozone budget amplified by poor understanding of the NOx cycle. In a polluted urban environment, interaction of gases and particles produce various new compounds that are difficult to measure with analytical tools available today [Thiemens, 2006]. Using oxygen triple isotopic measurement of NO3 to investigate gas to particle formation and chemical transformation in the ambient atmosphere, this study presents data obtained from aerosols sampled at NASA's Dryden Aircraft Operations Facility (DAOF) in Palmdale, CA during January and February, 2009 and Los Angeles International Airport (LAX) during Fall 2009, Winter 2010, and Spring 2010. The aerosols collected from jet aircraft exhaust in Palmdale exhibit an oxygen isotope anomaly (Delta17O =delta 17O -0.52 delta18O) increase with photochemical age of particles (-0.22 to 26.41‰) while NO3 concentration decreases from 53.76 - 5.35ppm with a radial distance from the jet dependency. Bulk aerosol samples from LAX exhibit seasonal variation with Delta17 O and NO3 concentration peaking in winter suggesting multiple sources and increased fossil fuel burning. Using oxygen triple isotopes of NO3, we are able to distinguish primary and secondary nitrate by aircraft emissions allowing new insight into a portion of the global nitrogen cycle. This represents a new and potentially important means to uniquely identify aircraft emissions on the basis of the unique isotopic composition of jet aircraft emissions.

  15. Gas and Particulate Aircraft Emissions Measurements: Impacts on local air quality.

    NASA Astrophysics Data System (ADS)

    Jayne, J. T.; Onasch, T.; Northway, M.; Canagaratna, M.; Worsnop, D.; Timko, M.; Wood, E.; Miake-Lye, R.; Herndon, S.; Knighton, B.; Whitefield, P.; Hagen, D.; Lobo, P.; Anderson, B.

    2007-12-01

    Air travel and freight shipping by air are becoming increasingly important and are expected to continue to expand. The resulting increases in the local concentrations of pollutants, including particulate matter (PM), volatile organic compounds (VOCs), and nitrogen oxides (NOX), can have negative impacts on regional air quality, human health and can impact climate change. In order to construct valid emission inventories, accurate measurements of aircraft emissions are needed. These measurements must be done both at the engine exit plane (certification) and downwind following the rapid cooling, dilution and initial atmospheric processing of the exhaust plume. We present here results from multiple field experiments which include the Experiment to Characterize Volatile Aerosol and Trace Species Emissions (EXCAVATE) and the four Aircraft Particle Emissions eXperiments (APEX- 1/Atlanta/2/3) which characterized gas and particle emissions from both stationary or in-use aircraft. Emission indices (EIs) for NOx and VOCs and for particle number concentration, refractory PM (black carbon soot) and volatile PM (primarily sulfate and organic) particles are reported. Measurements were made at the engine exit plane and at several downstream locations (10 and 30 meters) for a number of different engine types and engine thrust settings. A significant fraction of organic particle mass is composed of low volatility oil-related compounds and is not combustion related, potentially emitted by vents or heated surfaces within aircraft engines. Advected plumes measurements from in-use aircraft show that the practice of reduced thrust take-offs has a significant effect on total NOx and soot emitted in the vicinity of the airport. The measurements reported here represent a first observation of this effect and new insights have been gained with respect to the chemical processing of gases and particulates important to the urban airshed.

  16. 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.

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

    NASA Astrophysics Data System (ADS)

    Krejsa, E. A.

    The core noise levels from gas turbine aircraft engines were measured using a technique which 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 vore. 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.

  18. New technique for the direct measurement of core noise from aircraft engines. [YF 102 turbofan engine

    NASA Technical Reports Server (NTRS)

    Krejsa, E. A.

    1981-01-01

    The core noise levels from gas turbine aircraft engines were measured using a technique which 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 vore. 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.

  19. Absorption of Solar Radiation by the Cloudy Atmosphere Interpretations of Collocated Aircraft Measurements

    NASA Technical Reports Server (NTRS)

    Valero, Francisco P. J.; Cess, Robert D.; Zhang, Minghua; Pope, Shelly K.; Bucholtz, Anthony; Bush, Brett; Vitko, John, Jr.

    1997-01-01

    As part of the Atmospheric Radiation Measurement (ARM) Enhanced Shortwave Experiment (ARESE), we have obtained and analyzed measurements made from collocated aircraft of the absorption of solar radiation within the atmospheric column between the two aircraft. The measurements were taken during October 1995 at the ARM site in Oklahoma. Relative to a theoretical radiative transfer model, we find no evidence for excess solar absorption in the clear atmosphere and significant evidence for its existence in the cloudy atmosphere. This excess cloud solar absorption appears to occur in both visible (0.224-0.68 microns) and near-infrared (0.68-3.30 microns) spectral regions, although not at 0.5 microns for the visible contribution, and it is shown to be true absorption rather than an artifact of sampling errors caused by measuring three-dimensional clouds.

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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

  5. 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...

  6. 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.

  7. Comparison of Pandora spectrometer NO2 measurements to aircraft, satellite, and ground measurements during the DISCOVER-AQ Texas campaign

    NASA Astrophysics Data System (ADS)

    Judd, L.; Lefer, B. L.; Herman, J. R.; Abuhassan, N.; Cede, A.; Cohen, R. C.; Janz, S. J.; Ren, X.; Luke, W. T.; Long, R.

    2014-12-01

    Pandora spectrometer measurements are compared to other remotely sensed and in-situ NO2 measurements in the Houston, TX region during the third deployment of the DISCOVER-AQ campaign in September 2013. The network of freeways, petrochemical facilities, and related industries contribute to an ongoing pollution problem in the Houston region with the direct emissions of NOx and VOCs producing secondary pollutants such as ozone and PM2.5. The goal of this work is to determine how the Pandora spectrometer column measurements of NO2 compare to in-situ derived and other remotely sensed columns, as well as with ground measurements during this deployment of DISCOVER-AQ. UC Berkeley's LIF measurements of NO2 aboard the NASA P-3B at each spiral site are used to create the aircraft derived profiles of NO2. The aircraft measured profiles include upwind, source, and receptor sites in the region, three times a day, at eight different locations. In addition, we investigate how the NO2 profile shape changes both spatially and temporally, with a focus on the difference between the boundary layer and free troposphere distributions. Pandora measurements are also compared to column measurements from the Ozone Monitoring Instrument and ACAM aboard the B200 aircraft. Where available, surface measurements are included to supplement aircraft profiles and are correlated to the Pandora column measurements to determine the relationship between the total NO2 column and ground concentrations. Understanding of how these measurements compare spatially and temporally will aid both future Pandora deployments and satellite retrievals.

  8. Assimilating aircraft-based measurements to improve forecast accuracy of volcanic ash transport

    NASA Astrophysics Data System (ADS)

    Fu, G.; Lin, H. X.; Heemink, A. W.; Segers, A. J.; Lu, S.; Palsson, T.

    2015-08-01

    The 2010 Eyjafjallajökull volcano eruption had serious consequences to civil aviation. This has initiated a lot of research on volcanic ash transport forecast in recent years. For forecasting the volcanic ash transport after eruption onset, a volcanic ash transport and diffusion model (VATDM) needs to be run with Eruption Source Parameters (ESP) such as plume height and mass eruption rate as input, and with data assimilation techniques to continuously improve the initial conditions of the forecast. Reliable and accurate ash measurements are crucial for providing a successful ash clouds advice. In this paper, simulated aircraft-based measurements, as one type of volcanic ash measurements, will be assimilated into a transport model to identify the potential benefit of this kind of observations in an assimilation system. The results show assimilating aircraft-based measurements can significantly improve the state of ash clouds, and further providing an improved forecast as aviation advice. We also show that for advice of aeroplane flying level, aircraft-based measurements should be preferably taken from this level to obtain the best performance on it. Furthermore it is shown that in order to make an acceptable advice for aviation decision makers, accurate knowledge about uncertainties of ESPs and measurements is of great importance.

  9. 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.

  10. Characterization and application of an externally mounted catalytic converter for aircraft measurements of NOy

    NASA Astrophysics Data System (ADS)

    Lange, L.; Fischer, H.; Parchatka, U.; Gurk, C.; Zenker, T.; Harris, G. W.

    2002-08-01

    A novel design for an airborne NOy converter was implemented, characterized in the laboratory, and used extensively for in situ tropospheric and stratospheric measurements of total reactive nitrogen (NOy). During field deployments, the converter is mounted outside the aircraft fuselage, avoiding the need for an inlet line. In flight, the converter can be calibrated by the addition of standard gases close to the sample inlet, compensating for any changes in the instrument sensitivity caused by changing operating conditions. The system has been used successfully during several Stratosphere Troposphere Experiments by Aircraft Measurements campaigns in the lowermost stratosphere and upper troposphere for the measurement of total reactive nitrogen. The detection limit of the system is approximately 100 pptv for 10 s integrated data (2σ). The precision, deduced from the reproducibility of the in-flight calibrations, is 7% and the accuracy is about 30%. Laboratory studies demonstrate that interference from HCN, NH3, and CH3CN is negligible for background conditions.

  11. A solid state converter for measurement of aircraft noise and sonic boom

    NASA Technical Reports Server (NTRS)

    Zuckerwar, A. J.

    1972-01-01

    The problems inherent in present systems of instrumentation for measuring aircraft noise and sonic boom include limited frequency response, expensive connecting cables, sensitivity to cable length and type, high sensitivity to environmental conditions, and additional limitations of individual system components. Furthermore, differing requirements have resulted in the use of two different systems for aircraft noise and sonic boom measurements respectively. To alleviate these difficulties a unified system of instrumentation suitable for both types of measurements was developed. The system features a new solid state converter connected to a zero drive amplifier. The system was found insensitive to cable length and type up to at least 1000 ft and requires no impedance matching networks. The converter itself has flat frequency response from dc to 28 kHz (- 3 db), dynamic range of 72 db, and noise floor of 50 db in the band 22.4 Hz to 22.4 kHz.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Aircraft Measurements of Saharan dust properties and impact of atmospheric transport during Fennec

    NASA Astrophysics Data System (ADS)

    Ryder, Claire; Highwood, Ellie; Rosenberg, Phil; Trembath, Jamie; Brooke, Jennifer; Bart, Mark; Dean, Angela; Dorsey, James; Crosier, Jonny; McQuaid, Jim; Brindley, Helen; Banks, James; Marsham, John; Sodemann, Harald; Washington, Richard

    2013-04-01

    Measurements of Saharan dust from recent airborne campaigns have found variations in size distributions and optical properties across Saharan and sub-Saharan Africa. These variations have an impact on radiation and thus weather and climate, and are important to characterise and understand, in particular, to understand how they vary with time after dust uplift, transport, and height in the atmosphere. New in-situ aircraft measurements from the Fennec 2011 aircraft campaign over a remote part of the Sahara Desert and the Atlantic Ocean will be presented and compared to previous airborne measurements. Size distributions extending to 300 μm will be shown, representing measurements extending further into the coarse mode than previously published for Saharan dust. The dust sampled by the aircraft covered a wide variety of loadings, dust source regions (Mali, Mauritania and Algeria) and dust ages (from fresh uplift to several days old). A significant coarse mode was present in the size distribution measurements with effective diameter up to 23 μm, and the mean size distribution showed greater concentrations of coarse mode than previous aircraft measurements. Single scattering albedo (SSA) values at 550nm calculated from these size distributions revealed high absorption from 0.77 to 0.95, with a mean of 0.85. Directly measured SSA values were higher (0.91 to 0.99) but new instrumentation revealed that these direct measurements, behind Rosemount inlets, overestimate the SSA by 0.02 to 0.20 depending on the concentration of coarse particles present. This is caused by inlet inefficiencies and pipe losses. Previous measurements of SSA from aircraft measurements may also have been overestimates for this reason. This has a significant impact on atmospheric heating rates. The largest dust particles were encountered closest to the ground, and were most abundant in cases where dust was freshly uplifted. Number concentration, mass loading and extinction coefficient showed inverse

  17. Effect of creep in titanium alloy Ti-6Al-4V at elevated temperature on aircraft design and flight test

    NASA Technical Reports Server (NTRS)

    Jenkins, J. M.

    1984-01-01

    Short-term compressive creep tests were conducted on three titanium alloy Ti-6Al-4V coupons at three different stress levels at a temperature of 714 K (825 F). The test data were compared to several creep laws developed from tensile creep tests of available literature. The short-term creep test data did not correlate well with any of the creep laws obtained from available literature. The creep laws themselves did not correlate well with each other. Short-term creep does not appear to be very predictable for titanium alloy Ti-6Al-4V. Aircraft events that result in extreme, but short-term temperature and stress excursions for this alloy should be approached cautiously. Extrapolations of test data and creep laws suggest a convergence toward predictability in the longer-term situation.

  18. Characterization of a Photoacoustic Aerosol Absorption Spectrometer for Aircraft-based Measurements

    NASA Astrophysics Data System (ADS)

    Mason, B. J.; Wagner, N. L.; Richardson, M.; Brock, C. A.; Murphy, D. M.; Adler, G.

    2015-12-01

    Atmospheric aerosol directly impacts the Earth's climate through extinction of incoming and outgoing radiation. The optical extinction is due to both scattering and absorption. In situ measurements of aerosol extinction and scattering are well established and have uncertainties less than 5%. However measurements of aerosol absorption typically have uncertainties of 20-30%. Development and characterization of more accurate and precise instrumentation for measurement of aerosol absorption will enable a deeper understand of significance and spatial distribution of black and brown carbon aerosol, the effect of atmospheric processes on aerosol optical properties, and influence of aerosol optical properties on direct radiative forcing. Here, we present a detailed characterization of a photoacoustic aerosol absorption spectrometer designed for deployment aboard research aircraft. The spectrometer operates at three colors across the visible spectrum and is calibrated in the field using ozone. The field calibration is validated in the laboratory using synthetic aerosol and simultaneous measurements of extinction and scattering. In addition, the sensitivity of the instrument is characterized under conditions typically encountered during aircraft sampling e.g. as a function of changing pressure. We will apply this instrument characterization to ambient aerosol absorption data collected during the SENEX and SEAC4RS aircraft based field campaigns.

  19. 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

    2015-07-01

    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. PMID:26148549

  20. 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.

  1. An intercomparison of aircraft instrumentation for tropospheric measurements of sulfur dioxide

    NASA Technical Reports Server (NTRS)

    Gregory, Gerald L.; Davis, Douglas D.; Beltz, Nobert; Bandy, Alan R.; Ferek, Ronald J.; Thornton, Donald C.

    1993-01-01

    As part of the NASA Tropospheric Chemistry Program, a series of field intercomparisons have been conducted to evaluate the state-of-the art for measuring key tropospheric species. One of the objectives of the third intercomparison campaign in this series, Chemical Instrumentation Test and Evaluation 3 (CITE 3), was to evaluate instrumentation for making reliable tropospheric aircraft measurements of sulfur dioxide, dimethyl sulfide, hydrogen sulfide, carbon disulfide, and carbonyl sulfide. This paper reports the results of the intercomparisons of five sulfur dioxide measurement methods ranging from filter techniques, in which samples collected in flight are returned to the laboratory for analyses (chemiluminescent or ion chromatographic), to near real-time, in-flight measurements via gas chromatographic, mass spectrometric, and chemiluminescent techniques. All techniques showed some tendency to track sizeable changes in ambient SO2 such as those associated with altitude changes. For SO2 mixing ratios in the range of 200 pptv to a few ppbv, agreement among the techniques varies from about 30% to several orders of magnitude, depending upon the pair of measurements intercompared. For SO2 mixing ratios less than 200 pptv, measurements from the techniques are uncorrelated. In general, observed differences in the measurement of standards do not account for the flight results. The CITE 3 results do not unambiguously identify one or more of the measurement techniques as providing valid or invalid SO2 measurements, but identify the range of 'potential' uncertainty in SO2 measurements reported by currently available instrumentation and as measured under realistic aircraft environments.

  2. 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.

  3. Aircraft wake vortex velocity measurements using a scanning CO2 laser Doppler velocimeter

    NASA Technical Reports Server (NTRS)

    Dimarzio, C. A.; Sonnenschein, C. M.; Jeffreys, H. B.

    1975-01-01

    A CO2 laser Doppler velocimeter was employed in the study of pairs of counterrotating vortices trailing aircraft in an airport air space. A laser positioned on an extended runway centerline scans a vertical plane perpendicular to the centerline. Vortex location, measurement of vortex transport, and measurement of the properties of aircraft wake vortex flow fields are achieved via spectral analysis of the data. Highest amplitude in the spectrum, the associated maximum velocity, the highest velocity above the amplitude threshold, and the total number of frequency (velocity) cells above thresholds are studied as parameters in analysis of the vortex-associated flow field. The profile of the radial variation of tangential velocity is studied, and two special problems are examined: location of the vortex center and error introduced by crosswind.

  4. 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.

  5. 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.

  6. 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.

  7. 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

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

    PubMed

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

    1999-10-01

    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. PMID:10514368

  9. 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.

  10. 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.

  11. 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

  12. 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.

  13. 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. PMID:18751685

  14. Sonic booms produced by US Air Force and US Navy aircraft: Measured data

    NASA Astrophysics Data System (ADS)

    Lee, R. A.; Downing, J. M.

    1991-01-01

    A sonic measurement program was conducted at Edwards Air Force Base. Sonic boom signatures, produced by F-4, F-14, F-15, F-16, F-18, F-111, SR-71, and T-38 aircraft, were obtained under the flight track and at various lateral sites which were located up to 18 miles off-track. Thirteen monitors developed by Det 1 AL/BBE were used to collect full sonic boom waveforms, and nine modified dosimeters were used to collect supplemental peak overpressures and the C-weighted Sound Exposure Levels (CSEL) for 43 near steady supersonic flights of the above United States Air Force and United States Navy aircraft. This report describes the measured database (BOOMFILE) that contains sonic boom signatures and overpressures, aircraft tracking, and local weather data. These measured data highlight the major influences on sonic boom propagation and generation. The data from this study show that a constant offset of 26 from the peak overpressure expressed in dB gives a good estimate of the CSEL of a sonic boom.

  15. Aircraft control position indicator

    NASA Technical Reports Server (NTRS)

    Dennis, Dale V. (Inventor)

    1987-01-01

    An aircraft control position indicator was provided that displayed the degree of deflection of the primary flight control surfaces and the manner in which the aircraft responded. The display included a vertical elevator dot/bar graph meter display for indication whether the aircraft will pitch up or down, a horizontal aileron dot/bar graph meter display for indicating whether the aircraft will roll to the left or to the right, and a horizontal dot/bar graph meter display for indicating whether the aircraft will turn left or right. The vertical and horizontal display or displays intersect to form an up/down, left/right type display. Internal electronic display driver means received signals from transducers measuring the control surface deflections and determined the position of the meter indicators on each dot/bar graph meter display. The device allows readability at a glance, easy visual perception in sunlight or shade, near-zero lag in displaying flight control position, and is not affected by gravitational or centrifugal forces.

  16. 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.

  17. Application of an acoustic noise removal method to aircraft-based atmospheric temperature measurements.

    PubMed

    Hugo, Ronald J; Nowlin, Scott R; Hahn, Ila L; Eaton, Frank D; McCrae, Kim A

    2003-01-01

    An acoustic noise removal method is used to reject engine acoustical disturbances from aircraft-based atmospheric temperature measurements. Removal of engine noise from atmospheric temperature measurements allows a larger wave number range to be fit while quantifying the magnitude of atmospheric temperature turbulence. The larger wave number range was found to result in a more statistically certain spectral slope estimate, with up to a 50% reduction in the standard deviation of measured spectral slopes. The noise removal technique was found to break down under conditions of weak atmospheric temperature turbulence where the engine acoustical disturbance can be several orders of magnitude larger than atmospheric temperature turbulence. PMID:12558258

  18. Application of an acoustic noise removal method to aircraft-based atmospheric temperature measurements

    NASA Astrophysics Data System (ADS)

    Hugo, Ronald J.; Nowlin, Scott R.; Hahn, Ila L.; Eaton, Frank D.; McCrae, Kim A.

    2003-01-01

    An acoustic noise removal method is used to reject engine acoustical disturbances from aircraft-based atmospheric temperature measurements. Removal of engine noise from atmospheric temperature measurements allows a larger wave number range to be fit while quantifying the magnitude of atmospheric temperature turbulence. The larger wave number range was found to result in a more statistically certain spectral slope estimate, with up to a 50% reduction in the standard deviation of measured spectral slopes. The noise removal technique was found to break down under conditions of weak atmospheric temperature turbulence where the engine acoustical disturbance can be several orders of magnitude larger than atmospheric temperature turbulence.

  19. INTERCOMPARISON OF ATMOSPHERIC NITRIC ACID MEASUREMENTS AT ELEVATED AMBIENT CONCENTRATIONS

    EPA Science Inventory

    Several methods for measurement of ambient HNO3 were compared over a 9-day period during the Carbonaceous Species Methods Comparison Study at Glendora, CA, in August 1986. ourly averaged HNO3 concentrations were in the range 0.5-25 ppbv, with hourly maxima each day in excess of 1...

  20. 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.

  1. 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.

  2. Balloon and aircraft measurement of stratospheric sulfate mixing ratio following the El Chichon eruption

    NASA Technical Reports Server (NTRS)

    Gandrud, B. W.; Lazrus, A. L.; Kritz, M. A.

    1983-01-01

    Profiles of sulfate mixing ratio versus altitude over the range 15-28 km were obtained from filter samples collected aboard balloons and U-2 aircraft. Observations were made in the summer, fall, and winter following the March-April 1982, El Chichon eruption. Observed sulfate mixing ratios were approximately two orders of magnitude greater than typical background (not volcanically augmented) mixing ratios. The sulfate mixing ratios obtained form the aircraft filter measurements were in good agreement with the results from a wire impactor and a particle counter flown simultaneously. Computations of the amount of sulfate contained in a vertical column of sq m were in agreement with similar calculations from airborne lidar, balloon-borne particle counters, and Solar Mesosphere Explorer satellite radiance retrievals.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Balloon and aircraft measurement of stratospheric sulfate mixing ratio following the El Chichon eruption

    NASA Astrophysics Data System (ADS)

    Gandrud, B. W.; Lazrus, A. L.; Kritz, M. A.

    1983-11-01

    Profiles of sulfate mixing ratio versus altitude over the range 15-28 km were obtained from filter samples collected aboard balloons and U-2 aircraft. Observations were made in the summer, fall, and winter following the March-April 1982, El Chichon eruption. Observed sulfate mixing ratios were approximately two orders of magnitude greater than typical background (not volcanically augmented) mixing ratios. The sulfate mixing ratios obtained form the aircraft filter measurements were in good agreement with the results from a wire impactor and a particle counter flown simultaneously. Computations of the amount of sulfate contained in a vertical column of sq m were in agreement with similar calculations from airborne lidar, balloon-borne particle counters, and Solar Mesosphere Explorer satellite radiance retrievals.

  8. A complex permittivity and permeability measurement system for elevated temperatures

    NASA Technical Reports Server (NTRS)

    Friederich, Paul

    1990-01-01

    The three goals of this research include: (1) to fully develop a method to measure the permittivity and permeability of special materials as a function of frequency in the range of 2.6 to 18 GHz, and of temperatures in the range of 25 to 1100 C; (2) to assist LeRC in setting up an in-house system for the measurement of high-temperature permittivity and permeability; and (3) to measure the complex permittivity and permeability of special materials as a function of frequency and temperature to demonstrate the capability of the method. The method chosen for characterizing the materials relies on perturbation of a resonant cavity with a small volume of sample material. Different field configurations in the cavity can be used to separate electric and magnetic effects. The cavity consists of a section of rectangular waveguide terminated at each end of a vertical slot iris. The center of one wall is a small hole through which the sample is introduced.

  9. A complex permittivity and permeability measurement system for elevated temperatures

    NASA Technical Reports Server (NTRS)

    Friederich, Paul

    1990-01-01

    The three goals of this research include: (1) to fully develop a method to measure the permittivity and permeability of special materials as a function of frequency in the range of 2.6 to 18 GHz, and of temperature in the range of 25 to 1100 C; (2) to assist LeRC in setting up an in-house system for the measurement of high-temperature permittivity and permeability; and (3) to measure the complex permittivity and permeability of special materials as a function of frequency and temperature to demonstrate the capability of the method. The method chosen for characterizing the materials relies on perturbation of a resonant cavity with a small volume of sample material. Different field configurations in the cavity can be used to separate electric and magnetic effects. The cavity consists of a section of rectangular waveguide terminated at each end of a vertical slot iris. In the center of one wall is a small hole through which the sample is introduced.

  10. Comparison of remote sensing techniques for measurements of aircraft emissions indices at airports

    NASA Astrophysics Data System (ADS)

    Schaefer, Klaus P.; Jahn, Carsten; Sturm, Peter J.; Lechner, Bernhard; Bacher, Michael; Gostomczyk, Adam; Kabarowska, Barbara; Zalewski, Leszec; Dahl, Guenter

    2004-02-01

    The emission indices of aircraft engine exhausts were measured at airports non-intrusively by FTIR emission spectrometry at the engine nozzle exit as well as by FTIR absorption spectrometry and DOAS (Differential Optical Absorption Spectrometry) behind the aircraft. Two measurement campaigns were performed to compare these different measurement methods. A kerosene powered burner was operated in that way that the different methods were applied for the exhaust gas investigations during the same time and at nearly the same exhaust gas volume. The burner was built with a nozzle exit diameter of 37 cm and a power of about 150 kW. Fresh air was pumped into the burner tube by a fan. Calibration gases as pure CO and NO were added in different amounts to vary the concentration of these gases in the exhaust. The sampling probe of an intrusive measurement system was installed in the centre of the exhaust stream near the exhaust exit for measurements of these gases and CO2 as well as NO2, UHC, SO2 and O2. An APU (GTCP36-300) in a test bed was used in the same way. CO was mixed into the exhausts near the nozzle exit. The passive FTIR instrument was operated in the test bed using special noise and vibration isolation. The open-path instruments were installed at the chimney exit on the roof of the test bed building. The deviations between the different measurement methods were in the order of +/-10 up to +/-20 %.

  11. Measurement of local void fraction at elevated temperature and pressure

    SciTech Connect

    Duncan, D.; Trabold, T.A.

    1993-03-01

    Significant advances have recently been made in analytical and computational methods for the prediction of local thermal-hydraulic conditions in gas/liquid two-phase flows. There is, however, a need for extensive experimental data, for the dual purposes of constitutive relation development and code qualification. There is especially true of systems involving complicated geometries and/or extreme flow conditions for which little, if any, applicable information exists in the open literature. For the tests described in the present paper, a novel electrical probe has been applied to measure the void fraction in atmospheric pressure air/water flows, and steam/water mixtures at high temperature and pressure. The data acquired in the latter experiments are compared with the results of a one-dimensional two-fluid computational analysis.

  12. 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. PMID:24218113

  13. 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.

  14. First Results of Noy Measurements Made In Mozaic Aboard Commercial Aircraft

    NASA Astrophysics Data System (ADS)

    Volz-Thomas, A.; Paetz, H.-W.; Houben, N.; Petrick, W.; Heil, T.; Smit, H. G. J.; Kley, D.; Marenco, A.; Nedelec, P.

    The European MOZAIC Program comprises measurements of ozone and water va- por aboard five Airbus A340 aircraft operated by four European airlines. Since the beginning of the project in 1994, more than 130.000 hours of in flight data were col- lected. In the second phase of MOZAIC, a small, light-weight and fully automatic NOy instrument was developed at FZ-Jülich and certified by Lufthansa Technik. The NOy instrument, which is calibrated in-situ with zero air, NO and NO2, was installed aboard an aircraft of Lufthansa in Jan 2001 and is producing data since April 2001 (more than 200 successful flights so far). The instrument is exchanged and serviced at monthly intervals. The detection limit is 50 ppt at an integration time of 4s (principal time resolution 0.1 s). The NOy data obtained from flights between Europe, North America, Asia and Africa are discussed in terms of the correlation with the other trace gases (O3, H2O, and CO) which allow to identify the influence of stratospheric air and pollution plumes from the continental boundary layer. Recent aircraft emissions are detected as short spikes in the high resolution data.

  15. First Results of NOy Measurements Made in MOZAIC Aboard Commercial Aircraft

    NASA Astrophysics Data System (ADS)

    Volz-Thomas, A.; Paetz, H. W.; Houben, N.; Petrick, W.; Heil, T.; Smit, H. G.; Kley, D.; Marenco, A.; Nedelec, P.

    2001-12-01

    The European MOZAIC Program comprises measurements of ozone and water vapor aboard five Airbus A340 aircraft operated by four European airlines. Since the beginning of the project in 1994, more than 150.000 hours of in-flight data were collected. In the second phase of MOZAIC, a small, light-weight and fully automatic NOy instrument was developed at FZ-Jülich and certified by Lufthansa Technik. The NOy instrument, which is calibrated in-situ with zero air, NO and NO2, was installed aboard an aircraft of Lufthansa in Jan 2001 and is producing data since April 2001 (more than 100 successful flights so far). The instrument is exchanged and serviced at monthly intervals. The detection limit is 50 ppt at an integration time of 4s (principal time resolution 0.1 s). The NOy data obtained from flights between Europe, North America, Asia and Africa are discussed in conjunction with ozone and water vapor with respect to the influence of stratospheric air, pollution plumes from the continental boundary layer and aircraft emissions.

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

    NASA Astrophysics Data System (ADS)

    Krejsa, E. A.

    1981-07-01

    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. 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.

  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. 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

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

    NASA Astrophysics Data System (ADS)

    Hermann, M.; Weigelt, A.; Assmann, D.; Pfeifer, S.; Müller, T.; Conrath, T.; Voigtländer, J.; Heintzenberg, J.; Wiedensohler, A.; Martinsson, B. G.; Deshler, T.; Brenninkmeijer, C. A. M.; Zahn, A.

    2015-11-01

    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 onboard 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 are the key components of the CARIBIC OPSS. The instrument records individual particle pulses in the particle size range 130-1110 nm diameter (for a particle refractive index of 1.47-i0.006 for an upper tropospheric (UT) aerosol particle) 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 instruments measurement performance shows no pressure dependency and no 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 two 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.

  1. 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.

  2. 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.

  3. Measurement of EM Field Inside a Cruising Aircraft: Potential Problems for the Use of Mobile Phones on Board

    NASA Astrophysics Data System (ADS)

    Kohmura, A.; Picard, J.; Yonemoto, N.; Yamamoto, K.

    Electromagnetic (EM) emissions from portable electronic devices (PEDs) carried onboard aircraft can interfere with avionic systems. Several onboard systems using EM waves have been planned, such as mobile communications and UWB (ultra-wideband) entertainment services distribution. Manufacturers of this system develop schemes to avoid electromagnetic interference by the transmissions (emissions) of mobile phones with avionic systems; some local-specific problems still remain. The purpose of this chapter is to investigate to what extent non-GSM transmissions from the ground base stations reach inside a cruising aircraft. The EM field at the base station frequency bands is measured in a cruising small aircraft.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Further analysis of long-term measurements on board of Czech airlines aircraft

    NASA Astrophysics Data System (ADS)

    Ploc, O.; Spurný, F.

    2007-09-01

    Aircraft crew exposure represents an important challenge of actual occupational exposure. The accumulation of new data on its level is therefore an important task of radiation dosimetry. There are few types of equipment able to characterize it. One of them is an Si-diode-based spectrodosemeter "Liulin". It is an active device which measures total energy depositions in the semiconductor unit and after appropriate calibration, is also able to provide a separate estimation for both radiation components (non-neutron and neutron-like) of the radiation field on board. The device was fixed on board couple times in 2001, 2002, 2005 and 2006 for long-term measurements (60 days of operational time). This contribution brings the analysis of the database generated from accumulated data measured with this device and calculated by means of codes CARI-6 and EPCARD v3.2. Reasonably good agreement of all data sets could be stated in ordinary solar conditions. More measurements on aircraft flights in areas with higher vertical cut-off rigidities should be accomplished to accumulate more data to reach better statistics of integral and spectral values.

  9. 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.

  10. Measuring the turbulent wind vector with a weight-shift Microlight Aircraft

    NASA Astrophysics Data System (ADS)

    Metzger, S.; Junkermann, W.; Neidl, F.; Butterbach-Bahl, K.; Schmid, H. P.; Beyrich, F.; Zheng, X. H.; Foken, T.

    2009-09-01

    The Small Environmental Research Aircraft (SERA) D-MIFUs initial fields of application are aerosol / cloud and radiation transfer research. Therefore a comparatively slow (True Airspeed, TAS ~25 ms-1) but highly mobile microlight aircraft was envisaged. To broaden the application area of D-MIFU we explore whether the microlight can also be used for Eddy Covariance (EC) flux measurement. To obtain useful data sets for airborne EC a reliable turbulent Wind Vector (WV) measurement is a key requirement. Here we present methodology and results to calibrate and express performance and uncertainty of microlight based WV measurement. Specific attention is given to the influence of the flexible-wing weight-shift geometry on the WV measurement. For the WV measurement we equipped D-MIFU with a 70 cm long noseboom supporting a classical 5 hole probe and a fast 50 μm diameter thermocouple. An Inertial Navigation System (INS) supplies high accuracy ground speeds (Ï?=0.05 ms-1) and attitude angles (Ï?=0.03° , 0.1° respectively for heading). Data are stored with 10 Hz yielding a horizontal resolution of 2.5 m. The INS also allows to analyze aircraft dynamics such as 3d rotation rates and acceleration of the nacelle body. Further estimates for 3d acceleration of airfoil and noseboom are obtained at 100 Hz. The noseboom calibration coefficients under laboratory conditions were obtained by wind tunnel- and thermal bath measurements. To transfer these characteristics for in-flight conditions we carried out a series of flights with D-MIFU above the Boundary Layer under calm conditions. On basis of level flights at different power settings we were able to determine dynamic pressure-, sideslip- and attack angle offsets. Additionally forced maneuvers, such as e.g. phugoids, have been performed. By means of multivariate analysis these data are used to assess and minimize the impact of microlight nacelle and airfoil rapidly varying motions (RVM) on the WV components. In the final

  11. Remote sensing and photogrammetric studies: Part D: repeatability of elevation measurements--Apollo photography

    USGS Publications Warehouse

    Wu, Sherman S.C.; Schafer, Francis J.; Nakata, Gary M.; Jordan, Raymond

    1973-01-01

    Stereoscopic photographs of the Moon taken by the metric and panoramic cameras on board the service module of Apollo spacecraft provide a source for quantitative data on lunar topography. The accuracy of the topographic data depends, in part, on the repeatability of elevation measurements. The repeatability depends on contrast in the stereoscopic image and is affected by many factors, such as photographic quality, the photogrammetric instrument used, and illumination conditions. For the Moon, illumination conditions are important so that repeatability of elevation measurements may be statistically related to Sun elevation angles, local slopes, and albedos of surfaces. We have examined the effect of Sun elevation angle on repeatability, using Apollo 15 photographs (Wu, unpublished data), and extended the results to slope-related effects.

  12. 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

  13. 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.

  14. The measurement of linear and angular displacements in prototype aircraft - Instrumentation, calibration and operational accuracy

    NASA Astrophysics Data System (ADS)

    Storm van Leeuwen, Sam

    The design and development of angular displacement transducers for flight test instrumentation systems are considered. Calibration tools, developed to meet the accuracy requirements, allowed in situ calibration with short turn around times. The design of the control surface deflection measurement channels for the Fokker 100 prototype aircraft is discussed in detail. It is demonstrated that a bellows coupling provides accurate results, and that the levers and push-pull rod drive mechanisms perform well. The results suggest that a complex mechanical drive mechanism reduces the system accuracy.

  15. 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

  16. Aureole lidar: instrument design, data analysis, and comparison with aircraft spectrometer measurements.

    PubMed

    Hooper, W P

    1993-07-20

    A lidar system is developed to map extinction under the flight path of a P-3 aircraft. With a modified Cassegrainian telescope, signals from both wide and narrow fields of view are detected. The wide field-of-view detector senses the aureole signal generated by sea surface reflection and aerosol forward scattering. The narrow field-of-view detector senses the backscattering profile and the direct reflection off the sea surface. Optical depth and extinction profiles are derived from these signals. In comparisons made beween in situ aerosol-size spectrometer and lidar measurements, lidar profiles are smaller in magnitude but similar in shape to the spectrometer profiles. PMID:20830043

  17. 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

  18. High-Altitude Aircraft-Based Electric-Field Measurements above Thunderstorms

    NASA Technical Reports Server (NTRS)

    Bateman, M. G.; Blakeslee, R. J.; Bailey, J. C.; Stewart, M. F.; Blair, A. K.

    1999-01-01

    We have developed a new set of eight electric field mills that were flown on a NASA ER-2 high-altitude aircraft. During the Third Convection And Moisture EXperiment (CAMEX- 3; Fall, 1998), measurements of electric field, storm dynamics, and ice microphysics were made over several hurricanes. Concurrently, the TExas-FLorida UNderflights (TEFLUN) program was being conducted to make the same measurements over Gulf Coast thunderstorms. Sample measurements will be shown. Our new mills have an internal 16-bit A/D, with a resolution of 0.25 V/m per bit at high gain, with a noise level less than the least significant bit. A second, lower gain channel gives us the ability to measure fields as high as 150 kV/m.

  19. High-Altitude Aircraft-Based Electric-Field Measurements Above Thunderstorms

    NASA Technical Reports Server (NTRS)

    Bateman, M. G.; Blakeslee, R. J.; Bailey, J. C.; Stewart, M. F.; Blair, A. K.

    1999-01-01

    We have developed a new set of eight electric field mills that were flown on a NASA ER-2 high-altitude aircraft. During the Third Convection And Moisture EXperiment (CAMEX-3; Fall, 1998), measurements of electric field, storm dynamics, and ice microphysics were made over several hurricanes. Concurrently, the TExas-FLorida UNderflights (TEFLUN) program was being conducted to make the same measurements over Gulf Coast thunderstorms. Sample measurements are shown: typical flight altitude is 20km. Our new mills have an internal 16-bit A/D, with a resolution of 0.25V/m per bit at high gain, with a noise level less than the least significant bit. A second, lower gain channel gives us the ability to measure fields as high as 150 kV/m.

  20. Fault detection of aircraft system with random forest algorithm and similarity measure.

    PubMed

    Lee, Sanghyuk; 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

  1. Absorption of Solar Radiation by the Cloudy Atmosphere: Further Interpretations of Collocated Aircraft Measurements

    NASA Technical Reports Server (NTRS)

    Cess, R. D.; Zhang, Minghua; Valero, Francisco P. J.; Pope, Shelly K.; Bucholtz, Anthony; Bush, Brett; Zender, Charles S.

    1998-01-01

    We have extended the interpretations made in two prior studies of the aircraft shortwave radiation measurements that were obtained as part of the Atmospheric Radiation Measurements (ARM) Enhanced Shortwave Experiments (ARESE). These extended interpretations use the 500 nm (10 nm bandwidth) measurements to minimize sampling errors in the broadband measurements. It is indicated that the clouds present during this experiment absorb more shortwave radiation than predicted by clear skies and thus by theoretical models, that at least some (less than or equal to 20%) of this enhanced cloud absorption occurs at wavelengths less than 680 nm, and that the observed cloud absorption does not appear to be an artifact of sampling errors nor of instrument calibration errors.

  2. Validating AIRS upper atmosphere water vapor retrievals using aircraft and balloon in situ measurements

    NASA Astrophysics Data System (ADS)

    Hagan, D. E.; Webster, C. R.; Farmer, C. B.; May, R. D.; Herman, R. L.; Weinstock, E. M.; Christensen, L. E.; Lait, L. R.; Newman, P. A.

    2004-11-01

    This paper provides an initial assessment of the accuracy of the Atmospheric Infrared Sounder (AIRS) water vapor retrievals from 500 to 100 mbar. AIRS satellite measurements are compared with accurate aircraft (NASA WB57) and balloon in situ water vapor measurements obtained during the NASA Pre-Aura Validation Experiment (Pre-AVE) in Costa Rica during Jan. 2004. AIRS retrieval (each pressure level of a single footprint) of water vapor amount agrees with the in situ measurements to ~25% or better if matched closely in time (1 hr) and space (50-100 km). Both AIRS and in situ measurements observe similar significant variation in moisture amount over a two-day period, associated with large-scale changes in weather patterns.

  3. 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.

  4. 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.

  5. Land, Ocean and Ice sheet surface elevation retrieval from CALIPSO lidar measurements

    NASA Astrophysics Data System (ADS)

    Lu, X.; Hu, Y.

    2013-12-01

    Since launching in April 2006 the main objective of the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) mission has been studying the climate impact of clouds and aerosols in the atmosphere. However, CALIPSO also collects information about other components of the Earth's ecosystem, such as lands, oceans and polar ice sheets. The objective of this study is to propose a Super-Resolution Altimetry (SRA) technique to provide high resolution of land, ocean and polar ice sheet surface elevation from CALIPSO single shot lidar measurements (70 m spot size). The land surface results by the new technique agree with the United States Geological Survey (USGS) National Elevation Database (NED) high-resolution elevation maps, and the ice sheet surface results in the region of Greenland and Antarctic compare very well with the Ice, Cloud and land Elevation Satellite (ICESat) laser altimetry measurements. The comparisons suggest that the obtained CALIPSO surface elevation information by the new technique is accurate to within 1 m. The effects of error sources on the retrieved surface elevation are discussed. Based on the new technique, the preliminary data products of along-track topography retrieved from the CALIPSO lidar measurements is available to the altimetry community for evaluation.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. Dual-parameter radar rainfall measurement from space - A test result from an aircraft experiment

    NASA Technical Reports Server (NTRS)

    Kozu, Toshiaki; Nakamura, Kenji; Meneghini, Robert; Boncyk, Wayne C.

    1991-01-01

    An aircraft experiment has been conducted with a dual-frequency (X/Ka-bands) radar to test various rainfall retrieval methods from space. The authors test a method to derive raindrop size distribution (DSD) parameters from the combination of a radar reflectivity profile and a path-integrated attenuation derived from surface return, which may be available from most spaceborne radars. The estimated DSD parameters are reasonable in that the values generally fall within the range of commonly measured ones and that shifts in DSD parameters appear to be correlated with changes in storm type. The validity of the estimation result is also demonstrated by a consistency check using the Ka-band reflectivity profile which is independent of the DSD estimation process. Although errors may occur in the cases of nonuniform beam filling, these test results indicate the feasibility of the dual-parameter radar measurement from space in achieving a better accuracy in quantitative rainfall remote measurements.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. Reliability of measuring pelvic floor elevation with a diagnostic ultrasonic imaging device

    PubMed Central

    Ubukata, Hitomi; Maruyama, Hitoshi; Huo, Ming

    2015-01-01

    [Purpose] The purpose of this study was to investigate the reliability of measuring the amount of pelvic floor elevation during pelvic and abdominal muscle contraction with a diagnostic ultrasonic imaging device. [Subjects] The study group comprised 11 healthy women without urinary incontinence or previous birth experience. [Methods] We measured the displacement elevation of the bladder base during contraction of the abdominal and pelvic floor muscles was measured using a diagnostic ultrasonic imaging device. The exercise was a four-part operation undertaken with the subjects in the lateral position. The reliability analysis included use of the interclass correlation coefficient (ICC) was used to assess the reliability. [Results] ICC (1.1) values for the pelvic floor elevation measurement with a diagnostic ultrasonic imaging device were 0.98 [contraction of the transversus abdominis (TrA) muscle], 0.99 [contraction of pelvic floor muscles (PFMs)], 0.98 (co-contraction of the TrA and PFMs), and 0.98 (resistance of the TrA and PFMs). This study proved the reliability of the method because the coefficient of reliability was 0.97 or more for all of the measurements, even for those during exercise. [Conclusion] The diagnostic ultrasonic imaging device measures pelvic floor elevation with high reliability. PMID:26355420

  17. Evaluating Source Area Contributions from Aircraft Flux Measurements Over Heterogeneous Land Using Large-Eddy Simulation

    NASA Astrophysics Data System (ADS)

    Bertoldi, Giacomo; Kustas, William P.; Albertson, John D.

    2013-05-01

    The estimation of spatial patterns in surface fluxes from aircraft observations poses several challenges in the presence of heterogeneous land cover. In particular, the effects of turbulence on scalar transport and the different behaviour of passive (e.g. water vapour) versus active (e.g. temperature) scalars may lead to large uncertainties in the source area/flux-footprint estimation for sensible ( H) and latent ( LE) heat-flux fields. This study uses large-eddy simulation (LES) of the land-atmosphere interactions to investigate the atmospheric boundary-layer (ABL) processes that are likely to create differences in airborne-estimated H and LE footprints. We focus on 32~m altitude aircraft flux observations collected over a study site in central Oklahoma during the Southern Great Plains experiment in 1997 (SGP97). Comparison between the aircraft data and traditional model estimates provide evidence of a difference in source area for turbulent sensible and latent heat fluxes. The LES produces reasonable representations of the observed fluxes, and hence provides credible evidence and explanation of the observed differences in the H and LE footprints. Those differences can be quantified by analyzing the change in the sign of the spatial correlation of the H and LE fields provided by the LES model as a function of height. Dry patterns in relatively moist surroundings are able to generate strong, but localized, sensible heating. However, whereas H at the aircraft altitude is still in phase with the surface, LE presents a more complicated connection to the surface as the dry updrafts force a convergence of the surrounding moist air. Both the observational and LES model evidence support the concept that under strongly advective conditions, H and LE measured at the top of the surface layer (≈50 m) can be associated with very different upwind source areas, effectively contradicting surface-layer self-similarity theory for scalars. The results indicate that, under certain

  18. 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.

  19. Imaging and quantitative measurement of corrosion in painted automotive and aircraft structures

    NASA Astrophysics Data System (ADS)

    Sun, G.; Wang, Xun; Feng, Z. J.; Jin, Huijia; Sui, Hua; Ouyang, Zhong; Han, Xiaoyan; Favro, L. D.; Thomas, R. L.; Bomback, J. L.

    2000-05-01

    Some of the authors have shown that it is possible to image and make rapid, quantitative measurements of metal thickness loss due to corrosion on the rear surface of a single layer structure, with an accuracy better than one percent. These measurements are complicated by the presence of thick and/or uneven layers of paint on either the front surface, the back surface, or both. We will discuss progress in overcoming these complications. Examples from both automotive and aircraft structures will be presented.—This material is based in part upon work performed at the FAA Center for Aviation Systems Reliability operated at Iowa State University and supported by the Federal Aviation Administration Technical Center, Atlantic City, New Jersey, under Grant number 95-G-025, and is also supported in part by the Institute for Manufacturing Research, Wayne State University, and by Ford Motor Company. Supported by a Grant from Ford Motor Company.

  20. 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.

  1. 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.

  2. GLITTER: new lidar technique for cloud-base altimetry. Description and initial aircraft measurements.

    PubMed

    Gelbwachs, Jerry A; Farley, Robert W

    2004-05-10

    Knowledge of cloud-base heights is important for climate studies, weather, and military operations. Conventional lidar methods monitor cloud depths by direct transmission of the beam through the cloud and sensing the backscattered returns. These techniques are limited by severe optical scattering by cloud particles to thickness <0.5 km. We have conceived of a novel lidar method measurement for thick-cloud-base altimetry from above that is not restricted by cloud scattering. The new method, known as GLITTER (an acronym for glimpses of the lidar images through the empty regions), relies on cloud porosity and diffuse reflection from land features to sense cloud bottoms. An aircraft GLITTER lidar measured cloud bases at 3.7- and 4.5-km altitudes. These initial results represent a proof-of-principle demonstration of the new lidar method. PMID:15143824

  3. Comparison of Cirrus height and optical depth derived from satellite and aircraft measurements

    SciTech Connect

    Kastner, M.; Kriebel, K.T.; Meerkoetter, R.; Renger, W.; Ruppersberg, G.H.; Wendling, P. )

    1993-10-01

    During the International Cirrus Experiment (ICE'89) simultaneous measurements of cirrus cloud-top height and optical depth by satellite and aircraft have been taken. Data from the Advanced Very High Resolution Radiometer (AVHRR) onboard the NOAA polar-orbiting meteorological satellite system have been used together with the algorithm package AVHRR processing scheme over clouds, land and ocean (APOLLO) to derive optical depth. NOAA High-Resolution Infrared Radiation Sounder (HIRS) data have been used together with a bispectral technique to derive cloud-top height. Also, the optical depth of some contrails could be estimated. Airborne measurements have been performed simultaneously by using the Airborne Lidar Experiment (ALEX), a backscatter lidar. Comparison of satellite data with airborne data showed agreement of the top heights to about 500 m and of the optical depths to about 30%. These uncertainties are within the limits obtained from error estimates. 34 refs., 8 figs.

  4. Measurements of snow microstructure using field and laboratory methods across an elevational gradient in Colorado, USA

    NASA Astrophysics Data System (ADS)

    Durand, M. T.; Molotch, N. P.; Kim, E. J.; Margulis, S. A.; Courville, Z.; Bateni, S.

    2011-12-01

    Snow microstructure is one of the fundamental controls on the propagation of radiation through the snowpack, at wavelengths ranging from visible to microwave. Objective characterization of snow microstructure for radiative transfer modeling has long been a difficult issue. Traditionally measurements of snow microstructure have been made via hand lens or stereology. Geometric grain size or the maximum linear extent of prevailing grains can be measured using a ruled card or a loupe- style hand lens, but these measurements are prone to observer error. In the stereology approach, snow samples are obtained in the field, preserved via a casting agent, cut with a microtome and photographed in the lab, then analyzed to obtain the specific surface area; these measurements are time and resource intensive. More recently, field-based techniques have been developed, including contact spectroscopy and NIR photography. Contact spectroscopy has a vertical resolution ~2 cm, while the NIR camera has a vertical resolution ~1mm. Contact spectroscopy measures direct reflectance across the entire visible/NIR spectrum, while the NIR camera measures diffuse reflectance within a single wavelength band. In this study, our goal was to evaluate how accurately the contact spectroscopy and NIR photography characterize specific surface area for four different types of snow. Our study took place in Steamboat Springs, Colorado in late March, 2011. We measured grain size at four different elevations, approximately at four locations spanning an elevation gradient of ~1000 meters. At the lowest elevation, liquid water was present in the snowpack on some days, and significant melt-refreeze crusts were present throughout the pack. At the highest elevation, no evidence of melt metamorphism was observed, except for a basal melt-refreeze crust from the beginning of the season. In addition to evaluating the accuracy of each technique, we evaluated the sensitivity of each technique to easily-made user

  5. The Influence of Aircraft Speed Variations on Sensible Heat-Flux Measurements by Different Airborne Systems

    NASA Astrophysics Data System (ADS)

    Martin, Sabrina; Bange, Jens

    2014-01-01

    Crawford et al. (Boundary-Layer Meteorol 66:237-245, 1993) showed that the time average is inappropriate for airborne eddy-covariance flux calculations. The aircraft's ground speed through a turbulent field is not constant. One reason can be a correlation with vertical air motion, so that some types of structures are sampled more densely than others. To avoid this, the time-sampled data are adjusted for the varying ground speed so that the modified estimates are equivalent to spatially-sampled data. A comparison of sensible heat-flux calculations using temporal and spatial averaging methods is presented and discussed. Data of the airborne measurement systems , Helipod and Dornier 128-6 are used for the analysis. These systems vary in size, weight and aerodynamic characteristics, since the is a small unmanned aerial vehicle (UAV), the Helipod a helicopter-borne turbulence probe and the Dornier 128-6 a manned research aircraft. The systematic bias anticipated in covariance computations due to speed variations was neither found when averaging over Dornier, Helipod nor UAV flight legs. However, the random differences between spatial and temporal averaging fluxes were found to be up to 30 % on the individual flight legs.

  6. 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.

  7. Relationship between satellite-derived vegetation indices and aircraft-based CO2 measurements

    SciTech Connect

    Cihlar, J.; Caramori, P.H.; Schuepp, P.H.; Desjardins, R.L.; Macpherson, J.I. McGill Univ., Montreal Agriculture Canada, Centre for Land and Biological Resources Research, Ottawa National Research Council of Canada, Inst. for Aerospace Research, Ottawa )

    1992-11-01

    The objective of this study was to analyze the relationship between satellite-derived vegetation indices and CO2 uptake, as an initial step in exploring the possibility of using a satellite-derived vegetation index as a measure of net photosynthesis. The study area included the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE) site located on the Konza prairie and adjacent area as well as a transect between Manhattan and Salina. One third of the transect exhibited vegetation and terrain characteristics similar to those on the FIFE site, whereas cultivated land predominated in the remaining portion of the 75-km-long flight line. In June, July, August, and October 1987, several CO2 data sets were obtained using the National Research Council of Canada's Twin Otter research aircraft. The normalized difference vegetation index (NDVI) and the simple ratio (SR) were computed from NOAA AVHRR data acquired as part of FIFE. Aircraft and satellite data were processed to obtain spatially coincident and locally representative flux values. Results show a linear relationship between NDVI and CO2 uptake during a single day; however, a nonlinear relationship emerged when all data sets were combined. The data from FIFE and the regional transect were consistent for one date but differed for other periods. Overall, about 60 percent of total variability in CO2 flux was accounted for by the NDVI and 74 percent by the SR. 14 refs.

  8. 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

  9. Development, enhancement, and evaluation of aircraft measurement techniques for national ambient air quality standard criteria pollutants

    NASA Astrophysics Data System (ADS)

    Brent, Lacey Cluff

    The atmospheric contaminants most harmful to human health are designated Criteria Pollutants. To help Maryland attain the national ambient air quality standards (NAAQS) for Criteria Pollutants, and to improve our fundamental understanding of atmospheric chemistry, I conducted aircraft measurements in the Regional Atmospheric Measurement Modeling Prediction Program (RAMMPP). These data are used to evaluate model simulations and satellite observations. I developed techniques for improving airborne observation of two NAAQS pollutants, particulate matter (PM) and nitrogen dioxide (NO2). While structure and composition of organic aerosol are important for understanding PM formation, the molecular speciation of organic ambient aerosol remains largely unknown. The spatial distribution of reactive nitrogen is likewise poorly constrained. To examine water-soluble organic aerosol (WSOA) during an air pollution episode, I designed and implemented a shrouded aerosol inlet system to collect PM onto quartz fiber filters from a Cessna 402 research aircraft. Inlet evaluation conducted during a side-by-side flight with the NASA P3 demonstrated agreement to within 30%. An ion chromatographic mass spectrometric method developed using the NIST Standard Reference Material (SRM) 1649b Urban Dust, as a surrogate material resulted in acidic class separation and resolution of at least 34 organic acids; detection limits approach pg/g concentrations. Analysis of aircraft filter samples resulted in detection of 8 inorganic species and 16 organic acids of which 12 were quantified. Aged, re-circulated metropolitan air showed a greater number of dicarboxylic acids compared to air recently transported from the west. While the NAAQS for NO2 is rarely exceeded, it is a precursor molecule for ozone, America's most recalcitrant pollutant. Using cavity ringdown spectroscopy employing a light emitting diode (LED), I measured vertical profiles of NO2 (surface to 2.5 km) west (upwind) of the Baltimore

  10. 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.

  11. Noise measurements at Stockton Airport obtained during engineering evaluation of two-segment approaches in a 727-222 aircraft

    NASA Technical Reports Server (NTRS)

    Glass, R. E.; Tanner, C. S.

    1973-01-01

    The results of acoustic measurements made on a 727-222 aircraft during standard ILS and two-segment approaches are presented. The aircraft was equipped with a special purpose glide slope computer to provide the capability of making two-segment noise abatement approaches. For upper segment computations, the computer used barometric-corrected pressure altitude and the slant range to a DME transmitter which was colocated with the glide slope transmitter. The computer used the ILS glide slope deviation for lower segment computations. Additional measurements were made on 737 revenue aircraft using the Stockton Airport. The purpose of the acoustical portion of the test was to measure and identify the noise levels during the various approaches.

  12. 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.

  13. Elevation angle alignment of quasi optical receiver mirrors of collective Thomson scattering diagnostic by sawtooth measurements

    SciTech Connect

    Moseev, D.; Meo, F.; Korsholm, S. B.; Leipold, F.; Michelsen, P. K.; Nielsen, S. K.; Salewski, M.; Stejner, M.; Bindslev, H.; Furtula, V.; Kantor, M.

    2012-10-15

    Localized measurements of the fast ion velocity distribution function and the plasma composition measurements are of significant interest for the fusion community. Collective Thomson scattering (CTS) diagnostics allow such measurements with spatial and temporal resolution. Localized measurements require a good alignment of the optical path in the transmission line. Monitoring the alignment during the experiment greatly benefits the confidence in the CTS measurements. An in situ technique for the assessment of the elevation angle alignment of the receiver is developed. Using the CTS diagnostic on TEXTOR without a source of probing radiation in discharges with sawtooth oscillations, an elevation angle misalignment of 0.9 Degree-Sign was found with an accuracy of 0.25 Degree-Sign .

  14. 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

  15. Loss rate of NO y from a power plant plume based on aircraft measurements

    NASA Astrophysics Data System (ADS)

    Gillani, N. V.; Luria, M.; Valente, R. J.; Tanner, R. L.; Imhoff, R. E.; Meagher, J. F.

    1998-09-01

    This study was motivated by the recent work of Buhr et al. [1996] which reported losses of NOy from large power plant plumes as high as 0.25 hour-1, much higher than generally accepted values. If true, conclusions pertaining to the efficiency of ozone and nitrate production in the lower troposphere would need major revisions. The results of Buhr et al. were based on aircraft measurements in four TVA (Tennessee Valley Authority) power plant plumes on July 7, 1995, as part of the Nashville/Middle Tennessee Ozone Study, a measurement program of the Southern Oxidants Study (SOS), whereas the results reported in this paper are also based on measurements made in the same SOS study aboard another instrumented aircraft (the TVA helicopter), in plumes of one of these power plants (the Cumberland Steam Plant in northwestern Tennessee) during five different days in 1994 and 1995. Between the 1994 and 1995 sampling periods, emissions of SO2 at the Cumberland plant were reduced by nearly 95% by installation of scrubbers. Our data from the one 1994 day show that the ratio of excess SO2 to NOy, in the plume core increased significantly with plume age, indicating a potentially high differential loss rate of NOy (excess loss of NOy relative to SO2) of about 0.12 hour-1. However, results based on the larger 1995 data set indicate a low differential NOy loss rate of only 0.00±0.03 hour-1, consistent with accepted low loss rates. Because the SOS-Nashville/Middle Tennessee Ozone Study was not specifically designed to explore the NOy loss issue, the question of NOy loss rates in plumes is not currently resolved and additional focused field studies are needed.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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. PMID:18357224

  1. Polarimetric measurements of sea surface brightness temperatures using an aircraft K-band radiometer

    NASA Technical Reports Server (NTRS)

    Yueh, Simon H.; Wilson, William J.; Li, Fuk K.; Nghiem, Son V.; Ricketts, William B.

    1995-01-01

    This paper presents the first experimental evidence that the polarimetric brightness temperatures of sea surfaces are sensitive to ocean wind direction in the incidence angle range of 30 to 50 degrees. Our experimental data were collected by a K-band (19.35 GHz) polarimetric wind radiometer (WINDRAD) mounted on the NASA DC-8 aircraft. A set of aircraft radiometer flights was successfully completed in November 1993. We performed circle flights over National Data Buoy Center (NDBC) moored buoys deployed off the northern California coast, which provided ocean wind measurements. The first WINDRAD flight was made on November 4, 1993. There was clear weather with a wind speed of 12 m/s at 330 degrees around the Pt. Arena buoy. We circled the buoy at three incidence angles, and all data when plotted as functions of azimuth angles show clear modulations of several Kelvin. At 40 degrees incidence angle, there is a 5 Kelvin peak-to-peak signal in the second Stokes parameter Q and the third Stokes parameter U. The Q data maximum is in the upwind direction and U has a 45 degrees phase shift in azimuth as predicted by theory. There is also an up/downwind asymmetry of 2 Kelvin in the Q data, and 1 Kelvin in the U data. At 50 degrees incidence angle, the collected data show very similar wind direction signatures to the SSM/I model function. Additional flights were made on other days under cloudy conditions. Data taken at a wind speed of 8 m/s show that at 40 degrees incidence Q and U have a smaller azimuthal modulation of 3 Kelvin, probably due to the lower wind speed. Additionally, the simultaneously recorded video images of sea surfaces suggested that Q and U data were less sensitive to unpolarized geophysical variations, such as clouds and whitecaps, while the T(v) and T(h) increased by a few Kelvin when the radiometer beam crossed over clouds, or there was a sudden increase of whitecaps in the radiometer footprint. The results of our aircraft flights indicate that passive

  2. Aircraft Measurements of Temperature and Liquid Water Content in Entrainment Interface Layer of Stratocumulus Clouds.

    NASA Astrophysics Data System (ADS)

    Haman, K. E.; Gerber, H.; Kumala, W.; Malinowski, S. P.

    2009-09-01

    Entrainment of dry, warm air from above the cloud and its mixing with the colder cloudy air is an important process in dynamics of inversion topped stratocumulus, leading to formation of a transition layer of complex structure - Entrainment Interface Layer (EIL). It consists of mutual filaments if cloudy and clear air of various thickness at different stages of stirring, mixing and homogenization. Borders between these filaments are often very sharp, with temperature jumps of few kelvins and liquid water content (LWC) jumps of up to 0.5 gmE-3 over distance of few centimeters, which cannot be resolved by means of standard aircraft instrumentation. This layer is an area of various specific dynamic and thermodynamic phenomena; in particular it is a source of downdrafts penetrating the cloud as the so called "cloud holes". Small scale structure of EIL has been investigated in 2001 during DYCOMS II campaign in marine stratocumulus over Eastern Pacific, by means of Ultrafast Aircraft Thermometer (UFT-F) from University of Warsaw and PVM-100A LWC-meter from Gerber Scientific, Inc. Some results of this research has been published in 2007 in Quarterly Journal of RMS. UFT-F has a thermoresistive sensing element protected against impact of cloud droplets and response time constant of order 10E-4s. PVM-100A is an optical instrument and has spatial resolution of order 10 cm. For recording a sampling rate of 1kHz has been typically applied with 10 kHz (for UFT-F only) on selected fragments of flights. Unfortunately, for some technical reasons, these two instruments, installed on the NCAR C-130 aircraft, were separated by about 6 meters what limited possibilities and precision of comparing their indications. There were also some failures during the flights due to which many potentially interesting measurements and observations have been lost. Opportunity to get improved observations of EIL appeared in 2008 at POST (Physics of Stratocumulus Top) Project. During POST a number of

  3. Cloud particle effects on laminar flow and instrumentation for their measurement aboard a NASA LFC aircraft

    NASA Technical Reports Server (NTRS)

    Davis, R. E.; Fischer, M. C.

    1983-01-01

    Fuel costs account now for approximately 60 percent of the direct operating costs of airlines and future commercial transport will utilize advanced technologies for saving fuel on the basis of drag reduction. Laminar flow control (LFC) represents such an advanced technology. A new laminar flow wing on a reconfigured WB-66 aircraft was tested in the X-21 flight program. The tests confirmed that extensive laminar flow could be achieved at subsonic transport cruise conditions. Factors affecting adversely the maintenance of laminar flow were found to be related to ice particles encountered during the penetration of cirrus clouds or haze. The present investigation is concerned with the effect of ice particles on LFC, taking into account the results obtained in the Leading Edge Flight Test (LEFT) being conducted by NASA. Attention is given to ice particle measurements in the LEFT program.

  4. Measurements of ocean surface spectrum from an aircraft using the two-frequency microwave resonance technique

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

    The present investigation is concerned with the results of a two-frequency (Delta k) microwave radar experiment conducted from an aircraft and aimed primarily at the development of remote sensing techniques to measure ocean surface wave spectral characteristics. The experiment was conducted as part of the Maritime Remote Sensing (MARSEN) project in the North Sea during the autumn of 1979. The objective was to demonstrate the feasibility of and study the performance of the Delta k technique from a higher altitude platform, at shallower incidence angles, and at higher Doppler velocities than earlier stationary platform experiments allowed. A quantitative engineering evaluation of the results of two comprehensive flights is provided, and the qualitative significance of the results is discussed from a geophysical point of view in terms of the existing theory.

  5. Aircraft noise problems

    NASA Astrophysics Data System (ADS)

    1981-01-01

    The problems related to aircraft noise were studied. Physical origin (sound), human reaction (noise), quantization of noise and sound sources of aircraft noise are discussed. Noise abatement at the source, technical, fleet-political and air traffic measures are explained. The measurements and future developments are also discussed. The position of Lufthansa as regards aircraft noise problems is depicted.

  6. 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. PMID:26257345

  7. 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.

  8. Theory and Apparatus for Measurement of Emissivity for Radiative Cooling of Hypersonic Aircraft with Data for Inconel and Inconel X

    NASA Technical Reports Server (NTRS)

    O'Sullivan, William J , Jr; Wade, William R

    1957-01-01

    The importance of radiation as a means of cooling high-supersonic- and hypersonic-speed aircraft is discussed to show the need for measurements of the total hemispherical emissivity of surfaces. The theory underlying the measurement of the total hemispherical emissivity of surfaces is presented, readily duplicable apparatus for performing the measurements is described, and measurements for stably oxidized Inconel and Inconel X are given for the temperature range from 600 F to 2,000 F.

  9. 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. PMID:23297898

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. Comparative evaluation of twenty pilot workload assessment measure using a psychomotor task in a moving base aircraft simulator

    NASA Technical Reports Server (NTRS)

    Connor, S. A.; Wierwille, W. W.

    1983-01-01

    A comparison of the sensitivity and intrusion of twenty pilot workload assessment techniques was conducted using a psychomotor loading task in a three degree of freedom moving base aircraft simulator. The twenty techniques included opinion measures, spare mental capacity measures, physiological measures, eye behavior measures, and primary task performance measures. The primary task was an instrument landing system (ILS) approach and landing. All measures were recorded between the outer marker and the middle marker on the approach. Three levels (low, medium, and high) of psychomotor load were obtained by the combined manipulation of windgust disturbance level and simulated aircraft pitch stability. Six instrument rated pilots participated in four seasons lasting approximately three hours each.

  15. Evaluation of a Wake Vortex Upset Model Based on Simultaneous Measurements of Wake Velocities and Probe-Aircraft Accelerations

    NASA Technical Reports Server (NTRS)

    Short, B. J.; Jacobsen, R. A.

    1979-01-01

    Simultaneous measurements were made of the upset responses experienced and the wake velocities encountered by an instrumented Learjet probe aircraft behind a Boeing 747 vortex-generating aircraft. The vortex-induced angular accelerations experienced could be predicted within 30% by a mathematical upset response model when the characteristics of the wake were well represented by the vortex model. The vortex model used in the present study adequately represented the wake flow field when the vortices dissipated symmetrically and only one vortex pair existed in the wake.

  16. 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.

  17. 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...

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

    NASA Astrophysics Data System (ADS)

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

    1993-12-01

    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 <25 pptv and <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 >25 pptv, the instruments agreed on average to about 15%. At mixing ratios <25 pptv the agreement was about 5 pptv. For CS2 (mixing ratios <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.

  19. 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.

  20. Aerosol-Cloud Interactions Evaluated with Aircraft Measurements during the Marine Stratus Experiment (MASE)"

    NASA Astrophysics Data System (ADS)

    Conant, W. C.; Arnott, P.; Bucholtz, A.; Buzorius, G.; Chuang, P. Y.; Jonsson, H. H.; Murphy, S. M.; Rissman, T. A.; Small, J. D.; Sorooshian, A.; Varutbangkul, V.; Flagan, R. C.; Seinfeld, J. H.

    2005-12-01

    In this presentation we explore how aerosols influence the microphysical, dynamical, and radiative properties of marine stratocumulus clouds. We address these aerosol-cloud interactions using data collected by the CIRPAS Twin Otter aircraft during the MASE (Marine Stratus Experiment) campaign, which was conducted off the coast of northern California in July of this year. The otter was instrumented to measure aerosol number concentration, size distribution from 15 nm - 2500 nm, composition (TOF-AMS; PILS), and light absorption. Furthermore, an array of optical probes on the aircraft provided detailed information on the cloud microphysics, including droplet concentration, size distribution, liquid water content and precipitation size distribution. Pyranometers measuring upwelling and downwelling solar irradiance (0.3 μm - 3.5 μm) mounted on a stabilized radiometer platform were used to obtain cloud albedo immediately above the region that was being profiled. Localized (2-20 km wide) regions of high aerosol concentration in the marine boundary layer (MBL) were found and identified as "ship tracks", although no coincident features were immediately apparent in the visible satellite images. Vertical profiles were conducted by the Twin Otter within and on both sides of each ship track to obtain the contrast in aerosol and cloud properties. The ship emissions enhanced aerosol number concentration by factors ranging from 2 to more than 10. They contribute almost entirely to sulfate aerosol -- there was virtually no change in organic aerosol concentration measured by the Aerodyne TOF-AMS or light absorption measured by a photoacoustic instrument within the tracks. The ship emissions are found to have a significant impact on the cloud microphysics, including nearly a doubling of droplet concentration and a reduction in effective radius. The change in droplet dispersion is found to be important in understanding the indirect effect. Cloud albedo tended to be slightly enhanced

  1. 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.

  2. Interior and exterior fuselage noise measured on NASA's C-8a augmentor wing jet-STOL research aircraft

    NASA Technical Reports Server (NTRS)

    Shovlin, M. D.

    1977-01-01

    Interior and exterior fuselage noise levels were measured on NASA's C-8A Augmentor Wing Jet-STOL Research Aircraft in order to provide design information for the Quiet Short-Haul Research Aircraft (QSRA), which will use a modified C-8A fuselage. The noise field was mapped by 11 microphones located internally and externally in three areas: mid-fuselage, aft fuselage, and on the flight deck. Noise levels were recorded at four power settings varying from takeoff to flight idle and were plotted in one-third octave band spectra. The overall sound pressure levels of the external noise field were compared to previous tests and found to correlate well with engine primary thrust levels. Fuselage values were 145 + or - 3 dB over the aircraft's normal STOL operating range.

  3. Comparison of aircraft noise measured in flight test and in the NASA Ames 40- by 80-foot wind tunnel.

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

    A method to determine free-field aircraft noise spectra from wind-tunnel measurements has been developed. The crux of the method is the correction for reverberations. Calibrated loud speakers are used to simulate model sound sources in the wind tunnel. Corrections based on the difference between the direct and reverberant field levels are applied to wind-tunnel data for a wide range of aircraft noise sources. To establish the validity of the correction method, two research aircraft - one propeller-driven (YOV-10A) and one turbojet-powered (XV-5B) - were flown in free field and then tested in the wind tunnel. Corrected noise spectra from the two environments agree closely.

  4. Mapping of sea ice and measurement of its drift using aircraft synthetic aperture radar images

    NASA Technical Reports Server (NTRS)

    Leberl, F.; Bryan, M. L.; Elachi, C.; Farr, T.; Campbell, W.

    1979-01-01

    Side-looking radar images of Arctic sea ice were obtained as part of the Arctic Ice Dynamics Joint Experiment. Repetitive coverages of a test site in the Arctic were used to measure sea ice drift, employing single images and blocks of overlapping radar image strips; the images were used in conjunction with data from the aircraft inertial navigation and altimeter. Also, independently measured, accurate positions of a number of ground control points were available. Initial tests of the method were carried out with repeated coverages of a land area on the Alaska coast (Prudhoe). Absolute accuracies achieved were essentially limited by the accuracy of the inertial navigation data. Errors of drift measurements were found to be about + or - 2.5 km. Relative accuracy is higher; its limits are set by the radar image geometry and the definition of identical features in sequential images. The drift of adjacent ice features with respect to one another could be determined with errors of less than + or - 0.2 km.

  5. 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.

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

    PubMed

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

    2016-02-01

    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. PMID:26730457

  7. Comparing modeled isoprene with aircraft-based measurements in the atmospheric boundary layer.

    SciTech Connect

    Doskey, P.; Gao, W.

    1997-12-12

    Nonmethane hydrocarbons (NMHCs) are involved in a complex series of reactions that regulate the levels of oxidants in the troposphere. Isoprene (C{sub 5}H{sub 8}), the primary NMHC emitted from deciduous trees, is one of the most important reactive hydrocarbons in the troposphere. The amount of isoprene entering the free troposphere is regulated by the compound's rate of emission from leaves and by chemical and physical processes in the forest canopy and the atmospheric boundary layer (ABL). This study uses a coupled canopy-ABL model to simulate these complex processes and compares calculated isoprene concentration profiles with those measured during aircraft flights above a forested region in the northeastern US. Land use information is coupled with satellite remote sensing data to describe spatial changes in canopy density during the field measurements. The high-resolution transport-chemistry model of Gao et al. (1993) for the ABL and the forest canopy layer is used to simulate vertical changes in isoprene concentration due to turbulent mixing and chemical reactions. The one-dimensional (1-D) ABL model includes detailed radiation transfer, turbulent diffusion, biogenic emissions, dry deposition, and chemical processes within the forest canopy and the ABL. The measured profiles are compared with the model simulations to investigate the biological, physical, and chemical processes that regulate the levels of isoprene within the ABL.

  8. Retrieval of cirrus cloud properties from comparative analyses of aircraft and satellite measurements made during the 1986 FIRE IFO

    NASA Technical Reports Server (NTRS)

    Hammer, Philip D.; Valero, Francisco P. J.; Kinne, Stefan; Hein, Paul F.

    1990-01-01

    Results are presented of a comparison of cirrus cloud properties obtained from aircraft measurements made during the FIRE Intensive Field Observations and Landsat 5 and NOAA-9 observations carried out during several near coincident overpasses by these satellites. Results of the analyses of these measurements and a comparison between measurements and model calculations were used to determine particle sizes within cirrus clouds and the IR optical depths.

  9. 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.

  10. 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.

  11. Prediction of aircraft sideline noise attenuation

    NASA Technical Reports Server (NTRS)

    Zorumski, W. E.

    1978-01-01

    A computational study is made using the recommended ground effect theory by Pao, Wenzel, and Oncley. It is shown that this theory adequately predicts the measured ground attenuation data by Parkin and Scholes, which is the only available large data set. It is also shown, however, that the ground effect theory does not predict the measured lateral attenuations from actual aircraft flyovers. There remain one or more important lateral effects on aircraft noise, such as sideline shielding of sources, which must be incorporated in the prediction methods. Experiments at low elevation angles (0 deg to 10 deg) and low-to-intermediate frequencies are recommended to further validate the ground effect theory.

  12. Surface slope and roughness measurement using ICESat/GLAS elevation and laser waveform

    NASA Astrophysics Data System (ADS)

    Li, Xiaolu; Xu, Kai; Xu, Lijun

    2016-09-01

    Surface slope and roughness are important geomorphological variables which have been used in the Earth and planetary sciences to infer material properties. For the ICESat/GLAS measurement, roughness and slope are two surface properties for broadening the width of the returned pulse. Based on this, a new method (GLAS waveform-derived roughness, GWR in short) is investigated to invert roughness from waveform broadening after excluding slope effect. Surface slope is estimated from the repeat tracks elevation of ICESat/GLAS, which is verified to be coincidence with geography facts (Landsat-7 images). Extensive experiments are performed using the proposed methods to evaluate the performance of surface properties (roughness, slope and elevation) in the Jakobshavn area. The experimental results demonstrate that, compared with the elevation-derived roughness method (GER in short), GWR is more sensitive to local surface properties in the gentle slope zone because it is a small-scale estimation. Additionally, GWR is a more stable roughness estimation which is immune to a strong elevation change.

  13. SIERRA-Flux: measuring regional surface fluxes of carbon dioxide, methane, and water vapor from an unmanned aircraft system

    NASA Astrophysics Data System (ADS)

    Fladeland, M. M.; Yates, E. L.; Bui, T. P.; Dean-Day, J. M.; Kolyer, R.; Schiro, K.; Berthold, R.; Iraci, L. T.; Loewenstein, M.

    2011-12-01

    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 more 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. In a series of flights in June of 2011, the NASA SIERRA carried a payload consisting of the NASA Ames Meteorological Measurement System (MMS) and a fast response (10Hz) CO2, CH4, and H2O vapor analyzer in order to demonstrate the feasibility of measuring fluxes from unmanned aircraft and to characterize accuracy and precision based upon ground measurements. The flights were conducted in Railroad Valley, NV in order to provide a simple model for understanding biases and uncertainties. This paper describes the system specifications, provides preliminary data compared against coincident ground measurements, and discusses future applications of the system.

  14. Development of an aircraft based instrument to measure the isotopes of water in the lower stratosphere.

    NASA Astrophysics Data System (ADS)

    Hanisco, T. F.; Kroll, J. H.; Anderson, J. G.

    2002-12-01

    The relative abundance of the hydrogen isotopes of water, H2O and HDO, is a sensitive indicator of the condensation history of an airmass in the upper troposphere and lower stratosphere. We have developed a technique that has the sensitivity to measure the relative abundance of H2O and HDO in situ aboard an aircraft flying in the upper troposphere and lower stratosphere. The instrument combines a new water photolysis system with our pre-existing instrument for laser induced fluorescence detection of OH. Water is photolyzed with an excimer lamp source at 172 nm, producing ground state OH and OD radicals. The radicals are detected with state selective laser induced fluorescence at 287 nm. The experiment has two unique characteristics. The first is the high sensitivity afforded by laser induced fluorescence detection. At stratospheric mixing ratios of H2O (4 ppm at 50 mbar), the relative abundance of H2O and HDO can be measured with a S/N > 12 in a 16 s acquisition cycle. The second is a reduction in the exchange of water isotopes on surfaces within the instrument: the OH and OD radicals are removed with near unity efficiency after collisions with walls in the system and are not detected.

  15. Aircraft measurements of the stable carbon isotopic ratio of atmospheric methane over Siberia

    NASA Astrophysics Data System (ADS)

    Sugawara, Satoshi; Nakazawa, Takakiyo; Inoue, Gen; Machida, Toshinobu; Mukai, Hitoshi; Vinnichenko, Nikolay K.; Khattatov, Vyachaslav U.

    1996-06-01

    Air samples collected using aircraft during the Siberian Terrestrial Ecosystem-Atmosphere-Cryosphere Experiments (STEACE) in the summer of 1993 and 1994 were analyzed for the carbon isotopic ratio, δ13C, of atmospheric CH4 as well as for the CH4 concentration. The CH4 concentrations and δ13C values observed in the lower troposphere over wetlands in the West Siberian Lowland varied considerably, showing a clear negative correlation between the two components. From the relationships between measured values of the CH4 concentration and δ13C, values of δ13C of CH4 released from wetlands into the atmosphere were estimated to be -75 to -67‰. The results observed over oil wells and pipelines showed isotopic evidence for leakage of natural gas. Mean values of δ13C measured in the middle and upper troposphere over Siberia in the summer season were -47.9±0.3 and -47.8±0.2‰ for 1993 and 1994, respectively, which are quite similar to each other.

  16. 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.

  17. 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.

  18. 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.

  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. 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.

  1. Comparison of in-situ, aircraft, and satellite based land surface temperature measurements

    NASA Astrophysics Data System (ADS)

    Baker, B.; Krishna, P.; Meyers, T. P.

    2013-12-01

    and surface temperature (LST) is a key variable used in surface energy budget studies, and in near-real time is assimilated into land surface models for short and medium range forecasts. Observations of LST over multiple years are also critical for climate trend assessment. However, accurate in-situ measurements of LST over continents are not yet available for the whole globe and are not routinely conducted at weather stations. Recently an effort has been underway to validate LST sensed remotely from satellites to the actual measured skin temperature using data from the United States Climate Reference Network (USCRN). The goal of this work is to quantify the spatial variability and the representativeness of the single-point skin temperature measurement already being made at USCRN sites. NOAA/ATDD is collaborating with the University of Tennessee Space Institute's (UTSI) Aviation Systems and Flight Research Department in Tullahoma, TN to utilize an instrumented aircraft to perform measurements of Earth's skin temperature over selected USCRN sites in the continental U.S. Airborne remote sensing is a powerful tool to assess the spatial variability of LST over a location with sufficient sampling density and has the operational flexibility depending on the study requirements. We will present the results from airborne campaigns made concurrently with satellite overpasses over a grassland site and a deciduous forest site, compare the relationship of surface temperature to air temperature at a number of CRN sites and show results of an intercomparison between the JPL reference skin temperature measurement and the CRN sensor.

  2. Morphological convexity measures for terrestrial basins derived from digital elevation models

    NASA Astrophysics Data System (ADS)

    Lim, Sin Liang; Daya Sagar, B. S.; Chet Koo, Voon; Tien Tay, Lea

    2011-09-01

    Geophysical basins of terrestrial surfaces have been quantitatively characterized through a host of indices such as topological quantities (e.g. channel bifurcation and length ratios), allometric scaling exponents (e.g. fractal dimensions), and other geomorphometric parameters (channel density, Hack's and Hurst exponents). Channel density, estimated by taking the ratio between the length of channel network ( L) and the area of basin ( A) in planar form, provides a quantitative index that has hitherto been related to various geomorphologically significant processes. This index, computed by taking the planar forms of channel network and its corresponding basin, is a kind of convexity measure in the two-dimensional case. Such a measure - estimated in general as a function of basin area and channel network length, where the important elevation values of the topological region within a basin and channel network are ignored - fails to capture the spatial variability between homotopic basins possessing different altitude-ranges. Two types of convexity measures that have potential to capture the terrain elevation variability are defined as the ratio of (i) length of channel network function and area of basin function and (ii) areas of basin and its convex hull functions. These two convexity measures are estimated in three data sets that include (a) synthetic basin functions, (b) fractal basin functions, and (c) realistic digital elevation models (DEMs) of two regions of peninsular Malaysia. It is proven that the proposed convexity measures are altitude-dependent and that they could capture the spatial variability across the homotopic basins of different altitudes. It is also demonstrated on terrestrial DEMs that these convexity measures possess relationships with other quantitative indexes such as fractal dimensions and complexity measures (roughness indexes).

  3. 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.

  4. 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.

  5. Aircraft Measurements of Aerosol Partitioning and Aging during EUCAARI-LONGREX

    NASA Astrophysics Data System (ADS)

    Morgan, W. T.; Allan, J. D.; Bower, K. N.; Coe, H.; Highwood, E. J.; McMeeking, G. R.; Northway, M. J.; Osborne, S. R.; Trembath, J.; Williams, P. I.

    2009-04-01

    The chemical composition of the atmospheric aerosol burden has significant implications for its climate impacts. Specifically, it determines the scattering or absorbing nature of the aerosol and its affinity for water uptake. Measurements of aerosol chemical composition are presented here from the UK Facility for Airborne Atmospheric Measurement (FAAM) BAe-146 research aircraft from May 2008. The BAe-146 operated out of Oberpfaffenhofen, Germany during the European Integrated Project on Aerosol Cloud Climate Air Quality Interactions (EUCAARI) LONG Range EXperiment (LONGREX). A primary goal of the study was to examine the effects of atmospheric aging on aerosol chemical, physical and optical properties. Science flights were conducted across Northern Europe, during a period of anticyclonic circulation in clear sky conditions. The aircraft employs a suite of aerosol instruments, which measure the chemical composition, microphysical, optical and hygroscopic properties of the in-situ aerosol population. An Aerodyne compact Time-of-Flight Aerosol Mass Spectrometer (cToF-AMS) measured the mass of volatile and semi-volatile particulate chemical constituents, as a function of size. These components included organic matter, nitrate, sulphate and ammonium. The spatial distribution and chemical evolution of these components will be presented. The chemical nature of the organic aerosol component is examined via Positive Matrix Factorisation (PMF). The factor analysis of the organic aerosol component revealed the dominance of Oxygenated Organic Aerosol (OOA) over Hydrocarbon-like Organic Aerosol (HOA). OOA is analogous to Secondary Organic Aerosol (SOA), whilst HOA is strongly associated with Primary Organic Aerosol (POA) derived from fossil fuel combustion. Two components were commonly resolved for the OOA component; an aged, more oxidised factor (reflecting the regional organic aerosol background) and a fresher (less aged) component, which exhibited less oxidation than the

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Comparison of in-situ, aircraft, and satellite based land surface temperature measurements over a mixed agricultural region

    NASA Astrophysics Data System (ADS)

    Krishnan, P.; Baker, B.; Kochendorfer, J.; Dumas, E.; Meyers, T. P.; Guillevic, P. C.; Corda, S.; Muratore, J. F.; Simmons, D.

    2013-12-01

    Land surface temperature (LST) is a key variable in the study of the exchange of energy and water between the land surface and the atmosphere, and it influences land surface physical processes at regional and global scales. With the objective of quantifying the spatial variability and overall representativeness of single-point surface temperature measurements and to improve the accuracy of satellite LST measurements, airborne campaigns were conducted over a mixed agricultural area near Bondville, Illinois during 2012 and 2013. During the campaigns, multiple measurements of surface temperature were made using infra-red temperature sensors at micrometeorological tower sites, which include NOAA's Climate Reference Network (CRN) and nearby flux tower sites, and onboard an instrumented Piper Navajo airborne research aircraft. In addition to this, daily LST products from the Moderate Resolution Imaging Spectroradiometer (MODIS), onboard the NASA Terra and Aqua Earth Observing System satellites were used. The aircraft-based and satellite-based LST measurements were compared with the in situ, tower-based LST measurements. Observations indicate large spatial and temporal variability of land surface temperature over the Bondville area. Our results show good agreement between in situ, aircraft and satellite measurements. The agreement was better with the LST data from the flux tower than those from CRN tower.

  11. Comparison of methane emissions from wetlands measured from aircraft and towers

    NASA Astrophysics Data System (ADS)

    Conley, S. A.; Faloona, I. C.; Drexler, J. Z.; Anderson, F. E.; Baldocchi, D. D.; Sturtevant, C. S.; Verfaillie, J. G.; Knox, S. H.

    2013-12-01

    The ability to estimate surface fluxes from light, fixed-wing aircraft is investigated during two flights over Twitchell Island, a heavily managed peatland dominated by irrigated crops approximately 6 km x 3 km in the Sacramento Delta. Flux towers provide a continuous measurement at a single point, while airborne fluxes provide a snapshot of a large area at a given time. The ability to integrate the two methods would provide a means to estimate a continuous regional flux from tower measurements. The single engine airplane (Mooney TLS), provided by Scientific Aviation, was flown around the island while concurrent flux measurements (latent & sensible heat, CO2, CH4) were being made from 4 m towers at two locations on the surface. The flux estimate made with the airplane uses horizontal mean wind measured in real-time from the airplane and the methane mixing ratio measured onboard with a Picarro f2301 analyzer. During the flights there was clear periodicity in all scalars measured coincident with the flight time required to circle the island (~6 minutes), indicating a connection between the surface and the observed signal in the airplane. For methane, higher mixing ratios were observed on the downwind side of the island. An internal boundary layer was observed, which we believe resulted from the Montezuma Hills wind farms upwind of Twitchell Island. Scalars were well-mixed throughout the depth of that internal boundary layer (~500m), which is shown to be consistent with a theoretical estimate of the internal boundary layer given the transition from the wind farm to the island vegetation. Surface emissions were estimated using a mass-balance approach where each of the terms in the scalar budget equation are estimated using a least squares minimization of the data while the airplane was within 10 km of the center of the island and the altitude was below 300 meters. Surface emission of methane during the first flight was estimated at 36 × 13 nmol m-2 s-1. During the

  12. Verification of FLYSAFE Clear Air Turbulence (CAT) objects against aircraft turbulence measurements

    NASA Astrophysics Data System (ADS)

    Lunnon, R.; Gill, P.; Reid, L.; Mirza, A.

    2009-09-01

    Prediction of gridded CAT fields The main causes of CAT are (a) Vertical wind shear - low Richardson Number (b) Mountain waves (c) Convection. All three causes contribute roughly equally to CAT occurrences, globally Prediction of shear induced CAT The predictions of shear induced CAT has a longer history than either mountain-wave induced CAT or convectively induced CAT. Both Global Aviation Forecasting Centres are currently using the Ellrod TI1 algorithm (Ellrod and Knapp, 1992). This predictor is the scalar product of deformation [akm1]and vertical wind shear. More sophisticated algorithms can amplify errors in non-linear, differentiated quantities so it is very likely that Ellrod will out-perform other algorithms when verified globally. Prediction of mountain wave CAT The Global Aviation Forecasting Centre in the UK has been generating automated forecasts of mountain wave CAT since the late 1990s, based on the diagnosis of gravity wave drag. Generation of CAT objects In the FLYSAFE project it was decided at an early stage that short range forecasts of meteorological hazards, i.e. icing, Clear Air Turbulence, Cumulonimbus Clouds, should be represented as weather objects, that is, descriptions of individual hazardous volumes of airspace. For CAT, the forecast information on which the weather objects were based was gridded, that comprised a representation of a hazard level for all points in a pre-defined 3-D grid, for a range of forecast times. A "grid-to-objects" capability was generated. This is discussed further in Mirza and Drouin (this conference). Verification of CAT forecasts Verification was performed using digital accelerometer data from aircraft in the British Airways Boeing 747 fleet. A preliminary processing of the aircraft data were performed to generate a truth field on a scale similar to that used to provide gridded forecasts to airlines. This truth field was binary, i.e. each flight segment was characterised as being either "turbulent" or "benign". A

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  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. 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

  19. 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

  20. 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.

  1. 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.

  2. Transport In The Antarctic Lowermost Stratosphere Inferred From In-situ Aircraft Measurements

    NASA Astrophysics Data System (ADS)

    Werner, A.; Ivanova, E.; Riediger, O.; Schmidt, U.; Strunk, M.; Volk, M.

    During the APE-GAIA campaign in Ushuaia, Argentina (54 S) in September/October 1999 measurements of long-lived tracers were made on board the M55 Geophys- ica aircraft with the High Altitude Gas Analyser (HAGAR), an in-situ instrument designed and built at the Institute for Meteorology and Geophysics, University of Frankfurt. HAGAR consists of a two channel gas chromatograph (GC/ECD) com- bined with a non-dispersive IR analyser which together measure the species N2O, CFC11, CFC12, H1211, SF6, and CO2. Most of the data were obtained between 50S and 70S latitude outside and inside the Antarctic polar vortex up to altitudes of about 21 km. Good coverage of samples in the lowermost stratosphere is achieved during horizontal flight legs at potential temperatures < 380K as well as vertical profiles at various latitudes. To estimate transport into the lowermost stratosphere we will present simple mass- balance calculations based on a method by Ray et al. (JGR, Vol. 104, No.D21, p. 26565-26580, 1999). With the knowledge of mixing ratios of trace gases at the 380 K isentropic surface, the tropopause, and data within the lowermost stratosphere it is pos- sible to determine the portions of air coming from above 380 K and across the extrat- ropical tropopause. In order to investigate seasonal variations, comparisons are made with NASA-ER-2 data from the ASHOE/MAESA (1994) campaign. Hemispheric dif- ferences are discussed by comparing our results with the northern hemispheric results of Ray et al.

  3. 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

  4. Atmospheric Aerosol Sampling with Unmanned Aircraft Systems (UAS) in Alaska: Instrument Development, Payload Integration, and Measurement Campaigns

    NASA Astrophysics Data System (ADS)

    Barberie, S. R.; Saiet, E., II; Hatfield, M. C.; Cahill, C. F.

    2014-12-01

    Atmospheric aerosols remain one of biggest variables in understanding global climate. The number of feedback loops involved in aerosol processes lead to nonlinear behavior at the systems level, making confident modeling and prediction difficult. It is therefore important to ground-truth and supplement modeling efforts with rigorous empirical measurements. To this end, the Alaska Center for Unmanned Aircraft Systems Integration (ACUASI) at the University of Alaska Fairbanks has developed a new cascade DRUM-style impactor to be mounted aboard a variety of unmanned aircraft and work in tandem with an optical particle counter for the routine collection of atmospheric aerosols. These UAS-based aerosol samplers will be employed for measurement campaigns in traditionally hazardous conditions such as volcanic plumes and over forest fires. Here we report on the development and laboratory calibration of the new instrument, the integration with UAS, and the vertical profiling campaigns being undertaken.

  5. 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.

  6. Ocean current surface measurement using dynamic elevations obtained by the GEOS-3 radar altimeter

    NASA Technical Reports Server (NTRS)

    Leitao, C. D.; Huang, N. E.; Parra, C. G.

    1977-01-01

    Remote Sensing of the ocean surface from the GEOS-3 satellite using radar altimeter data has confirmed that the altimeter can detect the dynamic ocean topographic elevations relative to an equipotential surface, thus resulting in a reliable direct measurement of the ocean surface. Maps of the ocean dynamic topography calculated over a one month period and with 20 cm contour interval are prepared for the last half of 1975. The Gulf Stream is observed by the rapid slope change shown by the crowding of contours. Cold eddies associated with the current are seen as roughly circular depressions.

  7. 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.

  8. 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. PMID:24344348

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. A lidar instrument to measure H2O and aerosol profiles from the NASA ER-2 aircraft

    NASA Technical Reports Server (NTRS)

    Vaughan, W. R.; Browell, E. V.; Hall, W. M.; Averill, R. D.; Wells, J. G.; Hinton, D. E.; Goad, J. H.; Degnan, J. J.

    1986-01-01

    Plans to develop the Lidar Atmospheric Sensing Experiment (LASE) instrument to conduct scientific experiments aboard a NASA U-2 (ER-2) aircraft are described. The LASE measurement objectives are listed, and the design of the LASE instrument is discussed, including performance criteria for the laser transmitter, wavemeter, telescope, optical receiver, and associated electronics. The instrument function is depicted with a block diagram, and layouts of various components are presented.

  14. 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.

  15. Using unmanned aircraft to measure the impact of pollution plumes on atmospheric heating rates and cloud properties during the Cheju ABC Plume-Asian Monsoon Experiment (CAPMEX)

    NASA Astrophysics Data System (ADS)

    Venkata Ramana, M.; Ramanathan, V.; Nguyen, H.; Xu, Y.; Pistone, K.; Corrigan, C.; Feng, Y.; Zhu, A.; Kim, S.; Yoon, S.; Carmichael, G. R.; Schauer, J. J.

    2009-12-01

    The CAPMEX (Cheju ABC Plume-Asian Monsoon Experiment) campaign took place off the Coast of Cheju Island in South Korea to take advantage of the unique event associated with the shutdown of anthropogenic emissions surrounding Beijing during the Olympics in summer 2008. CAPMEX studied pollution plumes before, during, and after the Beijing reductions using ground-level and high-elevation measurements, i.e., from unmanned aircrafts. Additionally, the campaign documented the effect on solar heating and clouds due to aerosols carried by the long range transport of pollution plumes. The unmanned aerial vehicle (UAV) measurement component of this campaign took place during Aug 9 to Sept 30, 2008. The AUAV payload was mission-specific and was outfitted to perform a particular set of measurements. These measurements include aerosol concentration, aerosol size distribution, aerosol absorption, cloud drop size distribution, solar radiation fluxes (visible and broadband), and spectral radiative fluxes. Throughout the CAPMEX experiment, long-range transport of aerosols from Beijing, Shanghai and Marine plumes were sampled in aerosol layers up to 3-4 km above sea level. During this period, we captured both heavy and light pollution events and witnessed air masses from both pristine oceanic sources and from major cities including Beijing and Shanghai. Analysis of specific plumes allowed us to quantify the impact of anthropogenic pollution on heating rates and cloud properties.

  16. Simulation of the Impact of New Aircraft- and Satellite-based Ocean Surface Wind Measurements on Estimates of Hurricane Intensity

    NASA Technical Reports Server (NTRS)

    Uhlhorn, Eric; Atlas, Robert; Black, Peter; Buckley, Courtney; Chen, Shuyi; El-Nimri, Salem; Hood, Robbie; Johnson, James; Jones, Linwood; Miller, Timothy; Ruf, Chris

    2009-01-01

    The Hurricane Imaging Radiometer (HIRAD) is a new airborne microwave remote sensor currently under development to enhance real-time hurricane ocean surface wind observations. HIRAD builds on the capabilities of the Stepped Frequency Microwave Radiometer (SFMR), which now operates on NOAA P-3, G-4, and AFRC C-130 aircraft. Unlike the SFMR, which measures wind speed and rain rate along the ground track directly beneath the aircraft, HIRAD will provide images of the surface wind and rain field over a wide swath (approximately 3 times the aircraft altitude). To demonstrate potential improvement in the measurement of peak hurricane winds, we present a set of Observing System Simulation Experiments (OSSEs) in which measurements from the new instrument as well as those from existing platforms (air, surface, and space-based) are simulated from the output of a high-resolution (approximately 1.7 km) numerical model. Simulated retrieval errors due to both instrument noise as well as model function accuracy are considered over the expected range of incidence angles, wind speeds and rain rates. Based on numerous simulated flight patterns and data source combinations, statistics are developed to describe relationships between the observed and true (from the model s perspective) peak wind speed. These results have implications for improving the estimation of hurricane intensity (as defined by the peak sustained wind anywhere in the storm), which may often go un-observed due to sampling limitations.

  17. Infrared aircraft measurements of stratospheric composition over Antarctica during September 1987

    NASA Technical Reports Server (NTRS)

    Toon, Goeff C.; Farmer, C. B.; Lowes, L. L.; Schaper, P. W.; Blavier, J.-F.; Norton, R. H.

    1988-01-01

    The JPL Mark IV interferometer recorded high resolution, infared solar spectra from the NASA DC-8 aircraft during flights over Antarctica in September 1987. The atmospheric absorption features in these spectra were analyzed to determine the overburdens of O3, NO, NO2, HNO3, ClONO2, HCl, HF, CH4, N2O, CO, H2O and CFC-12. The spectra were obtained at latitudes which ranged between 64 degrees S and 86 degrees S, allowing the composition in the interior of the polar vortex to be compared with that at the edge. The latitude dependence observed for NO, HO2, HNO3, ClONO2, HCl and HF are summerized. The values at 30 deg S were observed on the ferry flight from New Zealand to Hawaii. The dashed lines connecting the two were interpolated across the region for which there are no measurements. The chemically perturbed region is seen to consist of a collar of high HNO3 and ClONO2 surrounding a core in which the overburdens of these and of HCl and NO2 are very low. Clear increases in the overburdens of HF and HNO3 were observed during the course of September in the vortex core. HCl and NO2 exhibited smaller, less significant increases. The overburdens of the tropospheric source gases, N2O, CH4, CF2Cl2, and H2O were observed to much smaller over Antarctica than at mid-latitudes. This, together with the fact that HF over Antarctica was more that double its mid-latitude value, suggests that downwelling has occurred.

  18. 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.

  19. 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.

  20. 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.

  1. Remote Sensing Measurements of Vertical and Horizontal Moisture Variations from Aircraft Instruments

    NASA Technical Reports Server (NTRS)

    Atkinson, R. J.; Guillory, Anthony R.; Jedlovec, Gary J.

    1998-01-01

    The research in this paper focuses on describing vertical and horizontal of water vapor variability using two remote sensing aircraft instruments. To achieve this goal we will compare precipitable water and upper level humidity estimates derived from the each of the instruments. The Multispectral Atmospheric Mapping Sensor (MAMS) is a visible and infrared radiometer with similar channels to that of the GOES imager. MAMS has flown aboard the NASA ER-2 numerous times. It has been used to validate features observed with the previous series of GOES satellites. MAMS data has been used to study precipitable water and upper level water vapor as well as other geophysical parameters. MAMS provides the opportunity to obtain water vapor Imagery at 6.7 mm. Upper tropospheric humidity can be computed using this channel in a similar fashion to that of Soden and Bretherton. In addition to the water vapor channel, MAMS records data In 3 other Infrared channels and 8 visible and near Infrared bands at high spatial resolution (I 00 Abstract: m). The 1 1 and 12 mm infrared channels allow for the application of a split technique to derive total precipitable water. The Udar Atmospheric Sensing Experiment (LASE) which uses the Differential Absorption Udar (DIAL) technique for obtaining simultaneous water vapor and aerosol profiles through the entire troposphere. LASE operates In the 81 5 nm wavelength region and uses a double pulsed Ti:sapphire laser that is locked onto a water vapor line. LASE has good horizontal (IO km) and excellent vertical (300 m) resolution. MAMS and LASE collected data simultaneously on several ER-2 flights in September 1995. LASE mixing ratio profiles will be Integrated for comparison with MAMS precipitable water estimates and the upper tropospheric humidity will be computed for the layer observed by the MAMS 6.7 mm channel for comparison for this time period. Results show a significant correlation between the measurements of the two Instruments. Regions of high

  2. 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.

  3. 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

  4. 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

  5. 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.

  6. 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.

  7. 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).

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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...

  13. 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

  14. 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.

  15. 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

  16. 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

  17. Improved Mapping of SuperDARN Observations Using Elevation Angle Measurements

    NASA Astrophysics Data System (ADS)

    Shepherd, S. G.; Greenwald, R. A.

    2013-12-01

    Over the past decade the network of ground-based HF radars known as SuperDARN has undergone an accelerating rate of expansion to higher and lower geomagnetic latitudes. Three distinct layers of radars now exist at mid, high and polar latitudes and are capable of making continuous measurements of plasma convection from ~50-90 degrees geomagnetic. The expanding network continues to improve the completeness of global convection electric field observations in addition to increasing the range of geomagnetic activity over which observations are made. With multiple overlapping measurements it is increasingly important for global convection maps, and for other studies, that measurements are mapped accurately above a geodetic sphere. By using elevation angle information it is possible to obtain better determinations of the mode of propagation and therefore improved geodetic location of the measurements. In this study we demonstrate that the improved mapping leads to better agreement between the measurements of the radars in the network and improves the resulting global convection patterns.

  18. 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)

  19. Sediment residence time distributions: Theory and application from bed elevation measurements

    NASA Astrophysics Data System (ADS)

    Voepel, Hal; Schumer, Rina; Hassan, Marwan A.

    2013-12-01

    distance and residence time probability distributions are the key components of stochastic models for coarse sediment transport. Residence time for individual grains is difficult to measure, and residence time distributions appropriate to field and laboratory settings are typically inferred theoretically or from overall transport characteristics. However, bed elevation time series collected using sonar transducers and lidar can be translated into empirical residence time distributions at each elevation in the bed and for the entire bed thickness. Sediment residence time at a given depth can be conceptualized as a stochastic return time process on a finite interval. Overall sediment residence time is an average of residence times at all depths weighted by the likelihood of deposition at each depth. Theory and experiment show that when tracers are seeded on the bed surface, power law residence time will be observed until a timescale set by the bed thickness and bed fluctuation statistics. After this time, the long-time (global) residence time distribution will take exponential form. Crossover time is the time of transition from power law to exponential behavior. The crossover time in flume studies can be on the order of seconds to minutes, while that in rivers can be days to years.

  20. 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.

  1. Measurement of ice stability in the high elevation Dry Valleys, Antarctica

    NASA Astrophysics Data System (ADS)

    Marinova, M.; McKay, C. P.; Heldmann, J. L.; Davila, A. F.

    2012-12-01

    The high-elevation Dry Valleys of Antarctica are a unique location for studying possible formational mechanisms and stability of permafrost. In particular, the hyper-arid and cold conditions do not allow for the presence of liquid water, meaning the exchange of water between the atmosphere and subsurface is through vapour diffusion. The hyper-arid conditions also result in significant desiccation of the subsurface, thus forming a dry permafrost layer - soil which has a temperature always below 0°C (cryotic), but which is dry (not ice-cemented). The high-elevation Dry Valleys of Antarctica are the only known location on Earth with a dry permafrost layer overlying the ice-cemented ground; dry permafrost is common on Mars. We have made direct calculations of the stability of subsurface ice in University Valley (1730 m; 77°S 51.8', 160°E 43'), by measuring the temperature and humidity (air, surface, subsurface) at different locations along the valley at high temporal resolution (30 min). We then calculated the vapour pressure at each location, which shows the movement of water vapour throughout the year. Based on atmospheric measurements, the mean atmospheric vapour pressure is lower than the mean vapour pressure over ice in the subsurface, and thus the subsurface ice should be quickly retreating. Yet ice-cemented ground is observed throughout the valley. This may be explained by our surface measurements which suggest that the ground is snow covered for more than half of the year. This results in the subsurface seeing an upper boundary condition which has a significantly higher vapour pressure than if the subsurface was directly responding to atmospheric conditions. Vapour flux calculations based on our temperature and humidity measurements show that while using the atmospheric conditions clearly shows the subsurface ice to be unstable, using the surface measurements results in a vapour flux, and ice retreat rate, which is over two orders of magnitude lower and

  2. 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. PMID:26406749

  3. An Empirical Approach to the Measurement of the Cosmic Radiation Field at Jet Aircraft Altitudes

    NASA Astrophysics Data System (ADS)

    Bennett, L. G. I.; Lewis, B. J.; Kitching, F.; Green, A. R.; Butler, A.

    With the publication number 60 of the International Commission on Radiological Protection (ICRP) in 1990 and the subsequent recognition that jet aircrew are routinely and occupationally exposed to elevated levels of cosmic radiation, various research groups (in Canada and in the European Union) have been involved in the survey of aircrew and measurement of cosmic radiation at jet altitudes. The group at the Royal Military College of Canada (RMC) first surveyed air force pilots and then aircrew of six Canadian airlines, using neutron-sensitive bubble detectors. In addition, equipment was flown in the cargo area on several scientific flights, including one in which a multi-sphere neutron spectrometer was used to measure the neutron spectrum at altitude. Successive flights included a more portable equipment suite consisting of passive and active (battery-operated) equipment, such as bubble detectors and TLDs, and an ion chamber and neutron counters, respectively, along with a tissue equivalent proportional counter (TEPC). The summation of the low and high LET results from the former equipment compared successfully to those from the TEPC on each flight. The data from numerous flights worldwide were then encapsulated into a program that calculates the radiation dose for any flight in the world at any period in the solar cycle. This experimentally-based program, Predictive Code for AIrcrew Radiation Exposure (PCAIRE) has been designed to be used by the airline industry to meet national dosimetry requirements. In Canada, for example, such a code can be used, supported by periodic measurements. With this latter requirement in mind and a desire to decrease equipment size, the LIULIN instrument has been flown and compared to the TEPC. Our evaluation of the LIULIN will be presented.

  4. Wildfires in eastern Texas in August and September 2000: Emissions, aircraft measurements, and impact on photochemistry

    NASA Astrophysics Data System (ADS)

    Junquera, Victoria; Russell, Matthew M.; Vizuete, William; Kimura, Yosuke; Allen, David

    The accuracy of wildfire air pollutant emission estimates was assessed by comparing observations of carbon monoxide (CO) and particulate matter (PM) concentrations in wildfire plumes to predictions of CO and PM concentrations, based on emission estimates and air quality models. The comparisons were done for observations made in southeast Texas in August and September of 2000. The fire emissions were estimated from acreage burned, fuel loading information, and fuel emission factor models. A total of 389 km 2 (96,100 acres) burned in wildfires in the domain encompassing the Houston/Galveston-Beaumont/Port Arthur (HGBPA) area during August and September 2000. On the days of highest wildfire activity, the fires resulted in an estimated 3700 tons of CO emissions, 250 tons of volatile organic carbon (VOC) emissions, 340 tons of PM 2.5, and 50 tons of NO x emissions; estimated CO and VOC emissions from the fires exceeded light duty gasoline vehicle emissions in the Houston area on those days. When the appropriate aircraft data were available, aloft measurements of CO in the fire plumes were compared to concentrations of CO predicted using the emission estimates. Concentrations estimated based on emission predictions and air quality models were within a factor of 2 of the observed values. The estimated emissions from fires were used, together with a gridded photochemical model, to characterize the extent of dispersion of the fire emissions and the photochemistry associated with the fire emissions. Although the dispersion and photochemical impacts varied from fire to fire, for wildfires less than 10,000 acres, the greatest enhancements of CO and ozone concentrations due to the fire emissions were generally confined to regions within 10-100 km of the fire. Within 10 km of these fires, CO concentrations can exceed 2 ppm and ozone concentrations can be enhanced by 60 ppb. The extent of photo-oxidant formation in the plumes was limited by NO x availability and isoprene

  5. Bias corrections of GOSAT SWIR XCO2 and XCH4 with TCCON data and their evaluation using aircraft measurement data

    NASA Astrophysics Data System (ADS)

    Inoue, Makoto; Morino, Isamu; Uchino, Osamu; Nakatsuru, Takahiro; Yoshida, Yukio; Yokota, Tatsuya; Wunch, Debra; Wennberg, Paul O.; Roehl, Coleen M.; Griffith, David W. T.; Velazco, Voltaire A.; Deutscher, Nicholas M.; Warneke, Thorsten; Notholt, Justus; Robinson, John; Sherlock, Vanessa; Hase, Frank; Blumenstock, Thomas; Rettinger, Markus; Sussmann, Ralf; Kyrö, Esko; Kivi, Rigel; Shiomi, Kei; Kawakami, Shuji; De Mazière, Martine; Arnold, Sabrina G.; Feist, Dietrich G.; Barrow, Erica A.; Barney, James; Dubey, Manvendra; Schneider, Matthias; Iraci, Laura T.; Podolske, James R.; Hillyard, Patrick W.; Machida, Toshinobu; Sawa, Yousuke; Tsuboi, Kazuhiro; Matsueda, Hidekazu; Sweeney, Colm; Tans, Pieter P.; Andrews, Arlyn E.; Biraud, Sebastien C.; Fukuyama, Yukio; Pittman, Jasna V.; Kort, Eric A.; Tanaka, Tomoaki

    2016-08-01

    We describe a method for removing systematic biases of column-averaged dry air mole fractions of CO2 (XCO2) and CH4 (XCH4) derived from short-wavelength infrared (SWIR) spectra of the Greenhouse gases Observing SATellite (GOSAT). We conduct correlation analyses between the GOSAT biases and simultaneously retrieved auxiliary parameters. We use these correlations to bias correct the GOSAT data, removing these spurious correlations. Data from the Total Carbon Column Observing Network (TCCON) were used as reference values for this regression analysis. To evaluate the effectiveness of this correction method, the uncorrected/corrected GOSAT data were compared to independent XCO2 and XCH4 data derived from aircraft measurements taken for 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 Japan Meteorological Agency (JMA), the HIAPER Pole-to-Pole observations (HIPPO) program, and the GOSAT validation aircraft observation campaign over Japan. These comparisons demonstrate that the empirically derived bias correction improves the agreement between GOSAT XCO2/XCH4 and the aircraft data. Finally, we present spatial distributions and temporal variations of the derived GOSAT biases.

  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. An automated flow calorimeter for heat capacity and enthalpy measurements at elevated temperatures and pressures

    NASA Astrophysics Data System (ADS)

    Yesavage, Victor F.

    1990-08-01

    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 to 600 K and 0 to 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 percent and a total variation of 0.05 percent. Additional data analysis indicated that the overall measurement uncertainty was conservatively estimated as 0.2 percent with an anticipated precision of 0.1 to 0.15 percent at all operating conditions.

  8. 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.

  9. 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.

  10. 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.

  11. In-Flight Lightning Measurements and Reconstruction on a Metallic and Composite Aircraft

    NASA Astrophysics Data System (ADS)

    Boiddin, J.-F.; Flourens, F.; De Boer, A.; Bardet, M.; Herve, A.; Perez, G.; Riccio, L.

    2012-05-01

    Based on the success of the In-flight Lightning Strike Damage Assessment System (ILDAS) project launched within the scope of the Sixth Framework Programme of the European Commission and completed in July 2009, the results described in this paper form part of the ILDAS2 project initiated by Airbus Operations SAS in partnership with EADS IW and NLR. The principle aim of ILDAS2 project is to develop a system installed aboard an aircraft in order to determine the level, the current waveform and the attachments points of a lightning strike during an aircraft flight. The expectations linked to ILDAS2, the functional architecture of the system, the status and the projection of this development will be presented.

  12. 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

  13. 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

  14. Measurement of ozone and water vapor by Airbus in-service aircraft: The MOZAIC airborne program, An overview

    NASA Astrophysics Data System (ADS)

    Marenco, Alain; Thouret, ValéRie; NéDéLec, Philippe; Smit, Herman; Helten, Manfred; Kley, Dieter; Karcher, Fernand; Simon, Pascal; Law, Kathy; Pyle, John; Poschmann, Georg; von Wrede, Rainer; Hume, Chris; Cook, Tim

    1998-10-01

    Tentative estimates, using three-dimensional chemistry and transport models, have suggested small ozone increases in the upper troposphere resulting from current aircraft emissions, but have also concluded to significant deficiencies in today's models and to the need to improve them through comparison with extended data sets. The Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC) program was initiated in 1993 by European scientists, aircraft manufacturers, and airlines to collect experimental data. Its goal is to help understand the atmosphere and how it is changing under the influence of human activity, with particular interest in the effects of aircraft. MOZAIC consists of automatic and regular measurements of ozone and water vapor by five long range passenger airliners flying all over the world. The aim is not to detect direct effects of aircraft emissions on the ozone budget inside the air traffic corridors but to build a large database of measurements to allow studies of chemical and physical processes in the atmosphere, and hence to validate global chemistry transport models. MOZAIC data provide, in particular, detailed ozone and water vapor climatologies at 9-12 km where subsonic aircraft emit most of their exhaust and which is a very critical domain (e.g., radiatively and stratosphere/troposphere exchanges) still imperfectly described in existing models. This will be valuable to improve knowledge about the processes occuring in the upper troposphere and the lowermost stratosphere, and the model treatment of near tropopause chemistry and transport. During MOZAIC I (January 1993-September 1996), fully automatic devices were developed, installed aboard five commercial Airbus A340s, and flown in normal airline service. A second phase, MOZAIC II, started in October 1996 with the aim of continuing the O3 and H2O measurements and doing a feasibility study of new airborne devices (CO, NOy). Between September 1994 and December 1997, 7500

  15. 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%.

  16. Aircraft measurements of gravity waves in the upper troposphere and lower stratosphere during the START08 field experiment

    NASA Astrophysics Data System (ADS)

    Zhang, Fuqing; Wei, Junhong; Zhang, Meng; Bowman, K. P.; Pan, L. L.; Atlas, E.; Wofsy, S. C.

    2015-07-01

    This study analyzes in situ airborne measurements from the 2008 Stratosphere-Troposphere Analyses of Regional Transport (START08) experiment to characterize gravity waves in the extratropical upper troposphere and lower stratosphere (ExUTLS). The focus is on the second research flight (RF02), which took place on 21-22 April 2008. This was the first airborne mission dedicated to probing gravity waves associated with strong upper-tropospheric jet-front systems. Based on spectral and wavelet analyses of the in situ observations, along with a diagnosis of the polarization relationships, clear signals of mesoscale variations with wavelengths ~ 50-500 km are found in almost every segment of the 8 h flight, which took place mostly in the lower stratosphere. The aircraft sampled a wide range of background conditions including the region near the jet core, the jet exit and over the Rocky Mountains with clear evidence of vertically propagating gravity waves of along-track wavelength between 100 and 120 km. The power spectra of the horizontal velocity components and potential temperature for the scale approximately between ~ 8 and ~ 256 km display an approximate -5/3 power law in agreement with past studies on aircraft measurements, while the fluctuations roll over to a -3 power law for the scale approximately between ~ 0.5 and ~ 8 km (except when this part of the spectrum is activated, as recorded clearly by one of the flight segments). However, at least part of the high-frequency signals with sampled periods of ~ 20-~ 60 s and wavelengths of ~ 5-~ 15 km might be due to intrinsic observational errors in the aircraft measurements, even though the possibilities that these fluctuations may be due to other physical phenomena (e.g., nonlinear dynamics, shear instability and/or turbulence) cannot be completely ruled out.

  17. 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.

  18. Measurements of the Concentration and Composition of CCN and IN at a High Elevation Site

    NASA Astrophysics Data System (ADS)

    Friedman, B.; Kulkarni, G.; Zelenyuk, A.; Beranek, J.; Pekour, M. S.; Hallar, A. G.; Mccubbin, I. B.; Cziczo, D. J.; Thornton, J. A.

    2011-12-01

    Field measurements of cloud condensation nuclei (CCN) and ice nuclei (IN) were conducted in March 2011 at Storm Peak Laboratory (elevation 3220 m m.s.l.). Measurements of CCN number concentrations and droplet size distributions at supersaturations of 0.05%, 0.1%, 0.2%, 0.4%, and 0.7% were conducted in parallel with Scanning Mobility Particle Sizer (SMPS) measurements of size distributions and number concentrations of ambient particles. SMPS number concentrations of the overall ambient aerosol population were used to calculate the fraction of particles activating as droplets at the supersaturations studied. Single Particle Mass Spectrometer (SPLAT II) was used to characterize number concentration, size, internal composition, and densities of individual particles present in the ambient air. In a separate set of experiments, a pumped counterflow virtual impactor (PCVI) was used to separate particles that activated as CCN from unactivated particles, using a 50% cutsize of approximately 2.5 microns. The droplet residuals from the activated particles were characterized by SPLAT and compared to the properties of the overall aerosol population in order to examine the effect of single particle mixing state, aerosol composition, and size on CCN activity as a function of supersaturation. The PNNL Compact Ice Chamber (CIC) was deployed to measure IN concentrations and ice crystal size distributions at temperatures ranging from 253K to 233K. SMPS number concentrations, size distributions, and SPLAT single particle measurements were also utilized to assess the ice nucleation properties of ambient particles as a function of the processing conditions in the PNNL CIC.

  19. 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.

  20. 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.

  1. 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%).

  2. Rheological and Mechanical Property Measurements of PMDI foam at Elevated Temperatures.

    SciTech Connect

    Nemer, Martin B.; Brooks, Carlton F.; Bion Shelden; Soehnel, Melissa Marie; Barringer, David Alan

    2014-10-01

    A study was undertaken to determine the viscosity of liquefied 20 lb/ft 3 poly methyl ene diisocyanate (PMDI) foam and the stress required to puncture solid PMDI foam at elevated temperatures. For the rheological measurements th e 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 log 10 ( m/Pa s) = 20.6 - 9.5 log 10 (T/degC) for temperatures below 170 degC. Above 170 degC, 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 th rough 20lb/ft 3 foam was 500 - 800 psi at temperatures from room temperature up to 180 degC . The mechanical pressure required to break through 10 lb/ft 3 was 170 - 300 psi at temperatures from room temperature up to 180 degC. We have not been able to cause gas to break through the 20 lb/ft 3 PMDI foam at gas pressures up to 100 psi.

  3. Measurements of the response of transport aircraft ceiling panels to fuel pool fires

    NASA Technical Reports Server (NTRS)

    Bankston, C. P.; Back, L. H.

    1985-01-01

    Tests were performed to characterize the responses of various aircraft ceiling panel configurations to a simulated post-crash fire. Attention was given to one currently used and four new ceiling configurations exposed to a fuel pool fire in a circulated air enclosure. The tests were controlled to accurately represent conditions in a real fire. The panels were constructed of fiberglass-epoxy, graphite-phenolic resin, fiberglass-phenolic resin, Kevlar-epoxy, and Kevlar-phenolic resin materials. The phenolic resin-backed sheets performed the best under the circumstances, except when combined with Kevlar, which became porous when charred.

  4. 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.

  5. 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.

  6. 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.

  7. 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

  8. 1.5 μm lidar anemometer for true air speed, angle of sideslip, and angle of attack measurements on-board Piaggio P180 aircraft

    NASA Astrophysics Data System (ADS)

    Augere, B.; Besson, B.; Fleury, D.; Goular, D.; Planchat, C.; Valla, M.

    2016-05-01

    Lidar (light detection and ranging) is a well-established measurement method for the prediction of atmospheric motions through velocity measurements. Recent advances in 1.5 μm Lidars show that the technology is mature, offers great ease of use, and is reliable and compact. A 1.5 μm airborne Lidar appears to be a good candidate for airborne in-flight measurement systems. It allows measurements remotely, outside aircraft aerodynamic disturbance, and absolute air speed (no need for calibration) with great precision in all aircraft flight domains. In the framework of the EU AIM2 project, the ONERA task has consisted of developing and testing a 1.5 μm anemometer sensor for in-flight airspeed measurements. The objective of this work is to demonstrate that the 1.5 μm Lidar sensor can increase the quality of the data acquisition procedure for aircraft flight test certification. This article presents the 1.5 μm anemometer sensor dedicated to in-flight airspeed measurements and describes the flight tests performed successfully on-board the Piaggio P180 aircraft. Lidar air data have been graphically compared to the air data provided by the aircraft flight test instrumentation (FTI) in the reference frame of the Lidar sensor head. Very good agreement of true air speed (TAS) by a fraction of ms‑1, angle of sideslip (AOS), and angle of attack (AOA) by a fraction of degree were observed.

  9. 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.

  10. Comparison of Shuttle Imaging Radar-B ocean wave image spectra with linear model predictions based on aircraft measurements

    NASA Technical Reports Server (NTRS)

    Monaldo, Frank M.; Lyzenga, David R.

    1988-01-01

    During October 1984, coincident Shuttle Imaging Radar-B synthetic aperture radar (SAR) imagery and wave measurements from airborne instrumentation were acquired. The two-dimensional wave spectrum was measured by both a radar ocean-wave spectrometer and a surface-contour radar aboard the aircraft. In this paper, two-dimensional SAR image intensity variance spectra are compared with these independent measures of ocean wave spectra to verify previously proposed models of the relationship between such SAR image spectra and ocean wave spectra. The results illustrate both the functional relationship between SAR image spectra and ocean wave spectra and the limitations imposed on the imaging of short-wavelength, azimuth-traveling waves.

  11. 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.

  12. Variability of cloud microphysical and optical parameters obtained from aircraft and satellite remote sensing measurements during RACE

    NASA Astrophysics Data System (ADS)

    Gultepe, I.; Isaac, G. A.; Strawbridge, K. B.

    2001-03-01

    Observations of low stratiform clouds made during the Radiation, Aerosol and Cloud Experiment (RACE) over the Bay of Fundy, Nova Scotia, on 15 August 1995, and central Ontario on 4 October 1995 were used in this study. Aircraft, LAND Resources SATellite System (LANDSAT) and the Center for Atmospheric Research Experiments (CARE) lidar observations are used to obtain effective radius (reff), droplet number concentration (Nd) and cloud optical thickness (). Radiation observations with 28.5 m resolution from the Thematic Mapper (TM) on LANDSAT were used. The 10.4-12.5 μm infrared channel with a field of view of 114 m was used for the blackbody temperature calculation. Comparisons are made between clouds over the Ontario region, representing clouds over the land and over the Bay of Fundy, representing clouds over the ocean. Results of the aircraft observations show that the leg averaged Nd, liquid water content (LWC) and reff over land were about 147+/-73 cm-3, 0.21+/-0.11 g m-3 and 7.7+/-1.7 μm, respectively. Corresponding parameters for the clouds over the ocean were approximately 61+/-34 cm-3, 0.12+/-0.07 g m-3 and 13.8+/-3 μm, respectively. The mean measured visible extinction coefficient (ext) was about 55+/-15 km-1 for all cases, and it was a strong function of both LWC and Nd. The horizontal variability in both aircraft and LANDSAT observations indicate the need to address inhomogeneity in the sub-grid scales of models.

  13. 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...

  14. Measures for the reduction of the noise and vibration level of apartment house elevators. [changes in construction and insulation measures

    NASA Technical Reports Server (NTRS)

    Enescu, N.; Munteanu, M.; Stan, A.

    1974-01-01

    The reduction of the level of elevator noise and vibrations in apartment buildings was studied. By improving the mounting and gearing conditions of the winch and soundproofing the winch chamber, as well as by covering the elevator's control panel, the noise and vibration level was appreciably reduced.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. Comparison of improved Aura Tropospheric Emission Spectrometer (TES) CO{sub 2} 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, G. B.

    2012-02-01

    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.

  20. Infrared lidar windshear detection for commercial aircraft and the edge technique, a new method for atmospheric wind measurement

    NASA Astrophysics Data System (ADS)

    Targ, Russell; Bowles, Roland L.; Korg, C. L.; Gentry, Bruce M.; Souilhac, Dominique J.

    1991-05-01

    National attention has focused on the critical problem of detecting and avoiding windshear since the crash on August 2, 1985, of a Lockheed L-1011 at Dallas/Fort Worth International Airport. As part of The NASA/FAA National Integrated Windshear Program, we have defined a measurable windshear hazard index that can be remotely sensed from an aircraft, to give the pilot information about the wind conditions he will experience at some later time if he continues along the present flight path. Our technology analysis and end-to-end performance simulation, which measured signal-to-noise ratios and resulting wind velocity errors for competing coherent lidar systems, showed that a Ho:YAG lidar at a wavelength of 2.1 μm and a CO2 lidar at 10.6 m can give the pilot information about the line-of-sight component of a windshear threat in a region extending from his present position to 2 to 4 km in front of the aircraft. This constitutes a warning time of 20 to 40 s, even under conditions of moderately heavy precipitation. Using these results, a Coherent Lidar Airborne Shear Sensor (CLASS), using a Q-switched CO2 laser at 10.6 μm, is being designed and developed for flight evaluation in early 1992. The edge technique is a powerful new method for the measurement of small frequency shifts which allows high accuracy measurement of atmospheric winds (0.2 to 1 m/sec) with high vertical resolution (10 meters) using currently available technology.

  1. Aircraft Control-Position Indicator

    NASA Technical Reports Server (NTRS)

    Dennis, D. V.

    1985-01-01

    Aircraft control-position indicator cockpit-mounted instrument that displays positions of elevator and ailerons to pilot. Display is cruciform array of lights: horizontal row of amber lights and vertical row of green lights representing aileron and elevator positions, respectively. Display used extensively in spin testing and has been trouble-free, with no maintenance required after about 30 hours of operation.

  2. 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.

  3. 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.

  4. 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.

  5. A comparison of cloud radiation fields obtained by in-situ aircraft measurements and a numerical simulation of a tropical mesoscale convective system

    NASA Technical Reports Server (NTRS)

    Wong, Takmeng; Stackhouse, Paul; Stephens, Graeme; Valero, Francisco

    1990-01-01

    The radiation budget of a tropical mesoscale convective system (MCS) is investigated by comparing in situ aircraft measurements obtained in a tropical MCS during the Equatorial Mesoscale Experiment (EMEX), and coordinated aircraft radiation measurements, with radiation profiles calculated using cloud properties obtained from a cloud model simulation of a tropical MCS. Preliminary results indicate that the stratiform region of the tropical System B simulation represents the gross properties of the observed stratiform system between 4.5 to 15 km. The flux profiles predicted by the model are consistent with observed fluxes.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. Infrared aircraft measurements of stratospheric composition over Antarctica during September 1987

    SciTech Connect

    Toon, G.C.; Farmer, C.B.; Lowes, L.L.; Schaper, P.W.; Blavier, J.F.; Norton, R.H. )

    1989-11-30

    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 O{sub 3}, NO, NO{sub 2}, HNO{sub 3}, ClNO{sub 3}, HCl, HF, CO{sub 2}, CH{sub 4}, N{sub 2}O, HCN, CO, H{sub 2}O, CFCl{sub 3}, and CF{sub 2}Cl{sub 2}. The results show a collar of high HNO{sub 3} and ClNO{sub 3} surrounding a core in which the burdens of these and of HCl and NO{sub 2} are very low. Clear increases in the burdens of HF and HNO{sub 3} were observed during the course of September in the Vortex core. HCl and NO{sub 2} exhibited smaller, less significant increases. The burdens of the tropospheric source gases, N{sub 2}O, CH{sub 4}, HCN, CFCl{sub 3}, CF{sub 2}Cl{sub 2}, CO, and H{sub 2}O, were observed to be much smaller over Antarctica than at mid-latitudes. This, together with the fact that HF over Antarctica was more than double its mid-latitude value, suggests that downwelling had occurred.

  13. 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.

  14. Quantifying consistency and biases between aircraft, balloon and remote sensing measurements of UT/LS water vapor during the WB-57 NASA MACPEX mission

    NASA Astrophysics Data System (ADS)

    Gao, R.; Rollins, A.; Thornberry, T. D.; Hall, E.; Jordan, A.; Hurst, D. F.; Smith, J. B.; Sargent, M. R.; Fahey, D. W.

    2011-12-01

    Mixing ratios of water vapor in Earth's upper troposphere and lower stratosphere (UT/LS) are low (< 10 ppmv), yet water in this region is a significant driver of climate. Significant discrepancies have repeatedly been observed between multiple high precision measurements of water vapor at these low values in the UT/LS, leading to uncertainty in the absolute value of the direct radiative forcing from stratospheric water vapor. During the NASA Mid-latitude Airborne Cirrus Properties Experiment (MACPEX) mission in March and April of 2011, measurements of water vapor in the UT/LS were made using the NOAA chemical ionization mass spectrometer (CIMS) and Harvard Lyman-α water vapor (HWV) instruments integrated on the NASA WB-57 based out of Ellington Field, TX. This was the first aircraft deployment of the CIMS instrument configured to measure water vapor. The CIMS carried a novel in situ calibration system using two independent water vapor standards that were in excellent agreement throughout the campaign. CIMS was also in excellent agreement with HWV, which operates and is calibrated using fundamentally different principles. The redundant and independent calibration systems of CIMS and HWV afford new confidence in the accuracy of these aircraft measurements. We compare these aircraft measurements of water vapor to those made with the MLS instrument on the AURA satellite, and to frost point balloon borne (NOAA FPH and CFH) measurements coordinated with the WB-57 descents from the LS. A persistent bias of 0.7 ppmv is observed between the frost point and aircraft measurements in the 3 to 10 ppmv range, with frost point being lower. The MLS measurements are less precise, but generally fall between the balloon and aircraft measurements in the LS. These measurements renew interest in comparisons in the tropics where even lower mixing ratios and higher saturations with respect to ice are encountered.

  15. 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.

  16. Measurements of CO in an aircraft experiment and their correlation with biomass burning and air mass origin in South America

    NASA Astrophysics Data System (ADS)

    Boian, C.; Kirchhoff, V. W. J. H.

    Carbon monoxide (CO) measurements are obtained in an aircraft experiment during 1-7 September 2000, conducted over Central Brazil in a special region of anticyclonic circulation. This is a typical transport regime during the dry season (July-September), when intense biomass burning occurs, and which gives origin to the transport of burning poluents from the source to distant regions. This aircraft experiment included in situ measurements of CO concentrations in three different scenarios: (1) areas of fresh biomass burning air masses, or source areas; (2) areas of aged biomass burning air masses; and (3) areas of clean air or pristine air masses. The largest CO concentrations were of the order of 450 ppbv in the source region near Conceicao do Araguaia (PA), and the smallest value near 100 ppbv, was found in pristine air masses, for example, near the northeast coastline (clean air, or background region). The observed concentrations were compared to the number of fire pixels seen by the AVHRR satellite instrument. Backward isentropic trajectories were used to determine the origin of the air masses at each sampling point. From the association of the observed CO mixing ratios, fire pixels and air mass trajectories, the previous scenarios may be subdivided as follows: (1a) source regions of biomass burning with large CO concentrations; (1b) regions with few local fire pixels and absence of contributions by transport. Areas with these characteristics include the northeast region of Brazil; (1c) regions close to the source region and strongly affected by transport (region of Para and Amazonas); (2) regions that have a consistent convergence of air masses, that have traveled over biomass burning areas during a few days (western part of the Cerrado region); (3a) Pristine air masses with origin from the ocean; (3b) regions with convergent transport that has passed over areas of no biomass burning, such as frontal weather systems in the southern regions.

  17. 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.

  18. The NASA IceBridge Project Quickly Delivers Snow and Ice Elevation Measurements of Dynamic Polar Landscapes

    NASA Astrophysics Data System (ADS)

    Tressel, S. S.; Kaminski, M. L.; Brodzik, M.

    2012-12-01

    NASA's Operation IceBridge was formulated to bridge the gap between the ICESat and ICESat-2 satellite missions. IceBridge data are collected by a wide variety of instrumentation aboard aircraft that trace routes around Greenland, Alaska and Antarctica, concentrating on areas experiencing accelerated change. Data parameters such as ice surface elevation, ice bottom elevation, snow and ice depth, grounding line position, sea ice distribution and freeboard are extracted at resolutions better than what can be expected by satellite. IceBridge provides the continuity of such data until the launch of the ICESat-2 satellite, expected in 2016. NSIDC manages the data distribution and makes the data available quickly and effectively to any and all interested parties. For example, the MCoRDS L1B Geolocated Radar Echo Strength Profiles data represents one of 60 total data products available through the IceBridge project. The MCoRDS L1B data for the Greenland 2012 campaign exhibit ice surface and ice bottom information for areas of Greenland between 27 March 2012 and 17 May 2012. In July of 2012, these data were made available on the NSIDC Web site, allowing users to begin analyzing the data only a couple of months after the data collection. The data are distributed in MATLAB files with associated PDF, TIFF and PNG files. Comparable data are available starting in 2009 for periodic campaigns covering both Greenland and Antarctica. These data can be combined with an array of other parameters to track the state of the most crucial areas of the Earth's cryosphere.

  19. The KILI2008 project: Precise measurement of the highest elevation of Africa: Mt. Kilimanjaro

    NASA Astrophysics Data System (ADS)

    Fernandes, R. M. S.; Msemwa, J.; Bos, M.

    2009-04-01

    In October 2008, an international project, called KILI2008, involving 19 researchers from institutions of six different countries, measured the orthometric height of Mount Kilimanjaro, the highest elevation of Africa. This mountain, a dormant volcano, is also considered the highest "stand-alone" (it has an almost perfectly shaped volcano form) and "walkable" (it is not necessary to use special climbing equipment) mountain in the world. Located on the plate boundary between Somalia and Victoria tectonic blocks, Mount Kilimanjaro is constituted by three major volcanic cones, Kibo (the highest), Mawenzi, and Shira and it started to be formed about 750000 years ago. Several attempts were carried out to observe the precise height of this mountain starting in 1952 when the British Ordnance Survey did the first determination of the height of Uhuru peak (the top of Kibo volcano) by triangulation points. The computed value was 5895m. In 1999, a first attempt to apply spatial techniques (GPS) has been done and a new value of approximately 5893m was obtained. However, the GPS data were obtained using short time of observations and the EGM96 global model was used to convert from ellipsoid height to orthometric height. Due the high uncertainty of this model in this region (reaching several meters), no definitive conclusions could be drawn about the most correct value of the orthometric height of Mount Kilimanjaro. In this project, we combine GPS (Global Positioning System) data with gravimetric observations. The gravimetric observations were necessary in order to construct a local geoid with sufficient accuracy. Three teams carried out observations during 10 days, with two teams carrying gravimetric around and in the mountain, whereas a third team was doing GPS observations on the top of the mountain. We present the methodologies and the results achieved. Particular attention is done to the comparison using different software packages and strategies to compute the ellipsoidal

  20. Long duration measurements of fading on a low elevation angle, 11-GHz satellite path

    NASA Technical Reports Server (NTRS)

    Vogel, Wolfhard J.; Torrence, Geoffrey W.

    1993-01-01

    Some rainfall rate and beacon fade results from the first 5 years of continuous observations of an 11.2 GHz satellite beacon with a 5.8 degree elevation angle in Austin, Texas are presented and compared to Consultative Committee for International Radio (CCIR) predictions.

  1. LiDAR measurement of seasonal snow accumulation along an elevation gradient in the southern Sierra Nevada, California

    NASA Astrophysics Data System (ADS)

    Kirchner, P. B.; Bales, R. C.; Molotch, N. P.; Flanagan, J.; Guo, Q.

    2014-10-01

    We present results from snow-on and snow-off airborne-scanning LiDAR measurements over a 53 km2 area in the southern Sierra Nevada. We found that snow depth as a function of elevation increased approximately 15 cm per 100 m, until reaching an elevation of 3300 m, where depth sharply decreased at a rate of 48 cm per 100 m. Departures from the 15 cm per 100 m trend, based on 1 m elevation-band means of regression residuals, showed slightly less steep increases below 2050 m; steeper increases between 2050 and 3300 m; and less steep increases above 3300 m. Although the study area is partly forested, only measurements in open areas were used. Below approximately 2050 m elevation, ablation and rainfall are the primary causes of departure from the orographic trend. From 2050 to 3300 m, greater snow depths than predicted were found on the steeper terrain of the northwest and the less steep northeast-facing slopes, suggesting that ablation, aspect, slope and wind redistribution all play a role in local snow-depth variability. At elevations above 3300 m, orographic processes mask the effect of wind deposition when averaging over large areas. Also, terrain in this basin becomes less steep above 3300 m. This suggests a reduction in precipitation from upslope lifting and/or the exhaustion of precipitable water from ascending air masses. Our results suggest a cumulative precipitation lapse rate for the 2100-3300 m range of about 6 cm per 100 m elevation for the accumulation period of 3 December 2009 to 23 March 2010. This is a higher gradient than the widely used PRISM (Parameter-elevation Relationships on Independent Slopes Model) precipitation products, but similar to that from reconstruction of snowmelt amounts from satellite snow-cover data. Our findings provide a unique characterization of the consistent, steep average increase in precipitation with elevation in snow-dominated terrain, using high-resolution, highly accurate data and highlighs the importance of solar

  2. LiDAR measurement of seasonal snow accumulation along an elevation gradient in the southern Sierra Nevada, California

    NASA Astrophysics Data System (ADS)

    Kirchner, P. B.; Bales, R. C.; Molotch, N. P.; Flanagan, J.; Guo, Q.

    2014-05-01

    We present results from snow-on and snow-off airborne-scanning LiDAR measurements over a 53-km2 area in the southern Sierra Nevada. We found that snow depth as a function of elevation increased approximately 15 cm 100 m-1, until reaching an elevation of 3300 m, where depth sharply decreased at a rate of 48 cm 100 m-1. Departures from the 15 cm 100 m-1 trend, based on 1-m elevation-band means of regression residuals, showed slightly less-steep increases below 2050 m; steeper increases between 2050-3300 m; and less-steep increases above 3300 m. Although the study area is partly forested, only measurements in open areas were used. Below approximately 2050 m elevation, ablation and rainfall are the primary causes of departure from the orographic trend. From 2050 to 3300 m, greater snow depths than predicted were found on the steeper terrain of the northwest and the less-steep northeast-facing slopes, suggesting that ablation, aspect, slope and wind redistribution all play a role in local snow-depth variability. At elevations above 3300 m orographic processes mask the effect of wind deposition when averaging over large areas. Also, terrain in this basin becomes less steep above 3300 m. This suggests a reduction in precipitation from upslope lifting, and/or the exhaustion of precipitable water from ascending air masses. Our results suggest a precipitation lapse rate for the 2100-3300 m range of about 6 cm 100 m-1 elevation. This is a higher gradient than the widely used PRISM (Parameter-elevation Relationships on Independent Slopes Model) precipitation products, but similar to that from reconstruction of snowmelt amounts from satellite snowcover data. Our findings provide a unique characterization of the consistent, steep average increase in precipitation with elevation in snow-dominated terrain, using high-resolution, highly-accurate data, as well as the importance of solar radiation, wind redistribution and mid-winter melt with regard to snow distribution.

  3. 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.

  4. A comparison of surface sensible and latent heat fluxes from aircraft and surface measurements in FIFE 1987

    NASA Technical Reports Server (NTRS)

    Kelly, Robert D.; Smith, Eric A.; Macpherson, J. Ian

    1990-01-01

    Surface fluxes of sensible and latent heat over a tall-grass prairie in central Kansas, as measured by 22 surface stations during FIFE 1987, are compared with values gained indirectly by linear extrapolation of aircraft-measured flux profiles to the surface. The results of 33 such comparisons covering the period 26 June to 13 October 1987 indicate that the sensible heat flux profiles were generally more linear with less scatter in the measurements at each level than were the latent heat flux profiles, the profile extrapolations of sensible heat flux in general underestimate the surface averages by about 30 percent, with slightly better agreement during periods of small flux, and the profile extrapolations of latent heat flux in general underestimate the surface averages by about 15 percent, with overestimates during periods of small fluxes (dry conditions) and overestimates during periods of large fluxes (moist conditions). Possible origins of the differences between the two sets of measurements are discussed, as directions for further research.

  5. Probing emissions of military cargo aircraft: description of a joint field measurement Strategic Environmental Research and Development Program.

    PubMed

    Cheng, Meng-Dawn; Corporan, Edwin; DeWitt, Matthew J; Spicer, Chester W; Holdren, Michael W; Cowen, Kenneth A; Laskin, Alex; Harris, David B; Shores, Richard C; Kagann, Robert; Hashmonay, Ram

    2008-06-01

    To develop effective air quality control strategies for military air bases, there is a need to accurately quantify these emissions. In support of the Strategic Environmental Research and Development Program project, the particulate matter (PM) and gaseous emissions from two T56 engines on a parked C-130 aircraft were characterized at the Kentucky Air National Guard base in Louisville, KY. Conventional and research-grade instrumentation and methodology were used in the field campaign during the first week of October 2005. Particulate emissions were sampled at the engine exit plane and at 15 m downstream. In addition, remote sensing of the gaseous species was performed via spectroscopic techniques at 5 and 15 m downstream of the engine exit. It was found that PM mass and number concentrations measured at 15-m downstream locations, after dilution-correction generally agreed well with those measured at the engine exhaust plane; however, higher variations were observed in the far-field after natural dilution of the downstream measurements was accounted for. Using carbon dioxide-normalized data we demonstrated that gas species measurements by extractive and remote sensing techniques agreed reasonably well. PMID:18581808

  6. Common Carotid Intima-Media Thickness Measurements Do Not Improve Cardiovascular Risk Prediction in Individuals With Elevated Blood Pressure

    PubMed Central

    Bots, Michiel L.; Groenewegen, Karlijn A.; Anderson, Todd J.; Britton, Annie R.; Dekker, Jacqueline M.; Engström, Gunnar; Evans, Greg W.; de Graaf, Jacqueline; Grobbee, Diederick E.; Hedblad, Bo; Hofman, Albert; Holewijn, Suzanne; Ikeda, Ai; Kavousi, Maryam; Kitagawa, Kazuo; Kitamura, Akihiko; Ikram, M. Arfan; Lonn, Eva M.; Lorenz, Matthias W.; Mathiesen, Ellisiv B.; Nijpels, Giel; Okazaki, Shuhei; O’Leary, Daniel H.; Polak, Joseph F.; Price, Jacqueline F.; Robertson, Christine; Rembold, Christopher M.; Rosvall, Maria; Rundek, Tatjana; Salonen, Jukka T.; Sitzer, Matthias; Stehouwer, Coen D.A.; Franco, Oscar H.; Peters, Sanne A.E.; den Ruijter, Hester M.

    2015-01-01

    Carotid intima-media thickness (CIMT) is a marker of cardiovascular risk. It is unclear whether measurement of mean common CIMT improves 10-year risk prediction of first-time myocardial infarction or stroke in individuals with elevated blood pressure. We performed an analysis among individuals with elevated blood pressure (ie, a systolic blood pressure ≥140 mm Hg and a diastolic blood pressure ≥ 90 mm Hg) in USE-IMT, a large ongoing individual participant data meta-analysis. We refitted the risk factors of the Framingham Risk Score on asymptomatic individuals (baseline model) and expanded this model with mean common CIMT (CIMT model) measurements. From both models, 10-year risks to develop a myocardial infarction or stroke were estimated. In individuals with elevated blood pressure, we compared discrimination and calibration of the 2 models and calculated the net reclassification improvement (NRI). We included 17 254 individuals with elevated blood pressure from 16 studies. During a median follow-up of 9.9 years, 2014 first-time myocardial infarctions or strokes occurred. The C-statistics of the baseline and CIMT models were similar (0.73). NRI with the addition of mean common CIMT was small and not significant (1.4%; 95% confidence intervals, −1.1 to 3.7). In those at intermediate risk (n=5008, 10-year absolute risk of 10% to 20%), the NRI was 5.6% (95% confidence intervals, 1.6–10.4). There is no added value of measurement of mean common CIMT in individuals with elevated blood pressure for improving cardiovascular risk prediction. For those at intermediate risk, the addition of mean common CIMT to an existing cardiovascular risk score is small but statistically significant. PMID:24614213

  7. 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

  8. Basal Melt and Thickness Change of the Antarctic Ice Shelves Revealed by the Lagrangian Elevation Measurement from Satellite Laser Altimetry

    NASA Astrophysics Data System (ADS)

    Lee, C.; Seo, K.; Scambos, T.

    2012-12-01

    We present a novel method for estimating the elevation change on the Antarctic ice shelves using laser altimetry data from the Ice Cloud and land Elevation Satellite (ICESat; 2003-2009). Unlike the conventional crossover or repeat-track analysis fixed on the geodetic position, we estimate the elevation change rate at points fixed on the surface of moving ice, i.e. in the Lagrangian coordinate system. The ICESat ground tracks are relocated into the Lagrangian coordinate system based on the velocity field from the interferometric synthetic aperture radar (InSAR) and then the elevation change rate is measured from their crossover differences. The thickness change rates converted from the elevation change rates through a hydrostatic formula are applied to the mass conservation equation in the Lagrangian coordinate system, in order to derive the basal melt rate. In Lagrangian approach, the crossover difference is less affected by the small-scale surface relief on the moving ice, which causes the large uncertainty of elevation change rate in the conventional (Eulerian) crossover analysis. The basal melt derived from the mass conservation equation is also less sensitive to the noises of gridded ice thicknesses in the Largrangian approach than in the Eulerian approach. Our analysis provides a reliable map of basal melt rate and thickness change rate in the Antarctic ice shelves, which is a snapshot for the ICESat period. The highest ice thinning rates, accompanying strongest basal melts, are observed in the small ice shelves along the Amundsen Sea coast. In the Ross Ice Shelf, the ice thickness change is mainly controlled by the shutdown of Kamb Ice Stream. The ice thinning is dominant in the Filchner-Ronne Ice Shelf and strong within 150 km from the ice front.

  9. Aircraft-measured indirect cloud effects from biomass burning smoke in the Arctic and subarctic

    DOE PAGESBeta

    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.; et al

    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

  10. 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

  11. 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

  12. 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

  13. 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

  14. 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

  15. 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.

  16. Growth of Lower Stratospheric HCl/Cly Since 1993: Observations from Aircraft (ALIAS), Balloon (MarkIV, FIRS-2), Space Shuttle (ATMOS), and Satellite (HALOE) Measurements

    NASA Technical Reports Server (NTRS)

    Webster, C. R.; Michelsen, H. A.; May, R. D.; Scott, D. C.; Herman, R. L.; Margitan, J. J.; Toon, G. C.; Sen, B.; Gunson, M. R.; Jucks, K. W.; Johnson, D. G.; Chance, K. V.; Traub, W. A.; Russell, J. M., III

    1998-01-01

    Measurements of HCl in the lower stratosphere (15-21 km) from aircraft, balloon, Space Shuttle, and satellite reveal a growth in its mean abundance relative to that of total inorganic chlorine (Cly) from HCl/Cly = 57(+/-5)% in early 1993 to 75(+/-7)% by the end of 1997.

  17. 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...

  18. Calibration of the visible and near-infrared channels of the NOAA-9 AVHRR using high-altitude aircraft measurements from August 1985 and October 1986

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

    Visible and near infrared wavelength sensors mounted on operational satellites now in use do not have onboard absolute calibration devices. One means of establishing an in-orbit calibration for a satellite sensor is to make simultaneous measurement of a bright, relatively uniform scene along the satellite view vector from a calibrated instrument on board a high altitude aircraft. Herein, aircraft data were recorded over White Sands, New Mexico at satellite overpass time. Comparison of the coincident aircraft and orbiting satellite data for the visible and near infrared wavelength channels of the NOAA-9 Advanced Very High Resolution Radiometer shows that the calibration of the visible channel was unchanged from prelaunch values, but that the near infrared channel has degraded 6 percent by Aug. 1985. By Oct. 1986 the visible channel had degraded 13 percent and the near infrared channel had degraded 19 percent.

  19. 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.

  20. NASA's Operation IceBridge: using instrumented aircraft to bridge the observational gap between ICESat and ICESat-2 laser altimeter measurements (Invited)

    NASA Astrophysics Data System (ADS)

    Studinger, M.; Koenig, L.; Martin, S.; Sonntag, J. G.

    2010-12-01

    In 2009, the NASA satellite laser altimeter mission ICESat (Ice, Cloud and Land Elevation Satellite), which was launched in 2003, ceased to operate. To bridge the gap in polar laser observations between ICESat and its replacement ICESat-2, which is not scheduled for launch until 2015, Operation IceBridge, a six-year NASA airborne mission, was initiated in 2009. From a series of yearly polar flights, Operation IceBridge uses airborne instruments to map rapidly changing areas in the Arctic and Antarctic, building on two decades of repeat airborne and satellite measurements. 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) and a high resolution stereographic camera (DMS). The first Operation IceBridge flights were conducted between March and May 2009 over the Arctic and between October and November 2009 over Antarctica. Since its start in 2009, Operation IceBridge has flown 69 science missions, 580 flight hours and collected more than 350,000 km of data. All Operation IceBridge data are available at NSDIC: http

  1. Design and test of a flexible electrochemical setup for measurements in aqueous electrolyte solutions at elevated temperature and pressure.

    PubMed

    Wiberg, Gustav K H; Fleige, Michael J; Arenz, Matthias

    2014-08-01

    We present a detailed description of the construction and testing of an electrochemical cell allowing measurements at elevated temperature and pressure. The cell consists of a stainless steel pressure vessel containing the electrochemical glass cell exhibiting a three electrode configuration. The design of the working electrode is inspired by conventional rotating disk electrode setups. As demonstrated, the setup can be used to investigate temperature dependent electrochemical processes on polycrystalline platinum and also high surface area type electrocatalysts. PMID:25173310

  2. Design and test of a flexible electrochemical setup for measurements in aqueous electrolyte solutions at elevated temperature and pressure

    NASA Astrophysics Data System (ADS)

    Wiberg, Gustav K. H.; Fleige, Michael J.; Arenz, Matthias

    2014-08-01

    We present a detailed description of the construction and testing of an electrochemical cell allowing measurements at elevated temperature and pressure. The cell consists of a stainless steel pressure vessel containing the electrochemical glass cell exhibiting a three electrode configuration. The design of the working electrode is inspired by conventional rotating disk electrode setups. As demonstrated, the setup can be used to investigate temperature dependent electrochemical processes on polycrystalline platinum and also high surface area type electrocatalysts.

  3. 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.

  4. In situ measurement of particulate number density and size distribution from an aircraft

    NASA Technical Reports Server (NTRS)

    Briehl, D.

    1974-01-01

    Commercial particulate measuring instruments were flown aboard the NASA Convair 990. A condensation nuclei monitor was utilized to measure particles larger than approximately 0.003 micrometers in diameter. A specially designed pressurization system was used with this counter so that the sample could be fed into the monitor at cabin altitude pressure. A near-forward light scattering counter was used to measure the number and size distribution particles in the size range from 0.5 to 5 micrometers and greater in diameter.

  5. Predicting visibility of aircraft.

    PubMed

    Watson, Andrew; Ramirez, Cesar V; Salud, Ellen

    2009-01-01

    Visual detection of aircraft by human observers is an important element of aviation safety. To assess and ensure safety, it would be useful to be able to be able to predict the visibility, to a human observer, of an aircraft of specified size, shape, distance, and coloration. Examples include assuring safe separation among aircraft and between aircraft and unmanned vehicles, design of airport control towers, and efforts to enhance or suppress the visibility of military and rescue vehicles. We have recently developed a simple metric of pattern visibility, the Spatial Standard Observer (SSO). In this report we examine whether the SSO can predict visibility of simulated aircraft images. We constructed a set of aircraft images from three-dimensional computer graphic models, and measured the luminance contrast threshold for each image from three human observers. The data were well predicted by the SSO. Finally, we show how to use the SSO to predict visibility range for aircraft of arbitrary size, shape, distance, and coloration. PMID:19462007

  6. Predicting Visibility of Aircraft

    PubMed Central

    Watson, Andrew; Ramirez, Cesar V.; Salud, Ellen

    2009-01-01

    Visual detection of aircraft by human observers is an important element of aviation safety. To assess and ensure safety, it would be useful to be able to be able to predict the visibility, to a human observer, of an aircraft of specified size, shape, distance, and coloration. Examples include assuring safe separation among aircraft and between aircraft and unmanned vehicles, design of airport control towers, and efforts to enhance or suppress the visibility of military and rescue vehicles. We have recently developed a simple metric of pattern visibility, the Spatial Standard Observer (SSO). In this report we examine whether the SSO can predict visibility of simulated aircraft images. We constructed a set of aircraft images from three-dimensional computer graphic models, and measured the luminance contrast threshold for each image from three human observers. The data were well predicted by the SSO. Finally, we show how to use the SSO to predict visibility range for aircraft of arbitrary size, shape, distance, and coloration. PMID:19462007

  7. 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.

  8. 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.

  9. Ozone Contamination in Aircraft Cabins. Appendix B: Overview papers. In-flight measurements

    NASA Technical Reports Server (NTRS)

    Perkins, P. J.

    1979-01-01

    The NASA Global Atmospheric Sampling Program ozone measurements were obtained to establish to characteristics of the ambient ozone concentration during routine operations and to determine the attenuation of ambient concentrations of cabin air systems from simultaneous ambient and in cabin measurements. The characteristics of ambient ozone include: (1) maximum concentration; (2) duration of ozone encounters; (3) frequency of ozone during a flight; (4) variability of ozone during a flight; (5) in relation to routes, altitude, and meteorological conditions.

  10. Aircraft Design

    NASA Technical Reports Server (NTRS)

    Bowers, Albion H. (Inventor); Uden, Edward (Inventor)

    2016-01-01

    The present invention is an aircraft wing design that creates a bell shaped span load, which results in a negative induced drag (induced thrust) on the outer portion of the wing; such a design obviates the need for rudder control of an aircraft.

  11. Aircraft Noise

    NASA Astrophysics Data System (ADS)

    Michel, Ulf; Dobrzynski, Werner; Splettstoesser, Wolf; Delfs, Jan; Isermann, Ullrich; Obermeier, Frank

    Aircraft industry is exposed to increasing public pressure aiming at a continuing reduction of aircraft noise levels. This is necessary to both compensate for the detrimental effect on noise of the expected increase in air traffic and improve the quality of living in residential areas around airports.

  12. 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

  13. 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.

  14. Near UV atmospheric absorption measurements from the DC-8 aircraft during the 1987 airborne Antarctic ozone experiment

    NASA Technical Reports Server (NTRS)

    Wahner, A.; Jakoubek, R. O.; Ravishankara, A. R.; Mount, G. H.; Schmeltekopf, A. L.

    1988-01-01

    During the Airborne Antarctic Ozone Experiment from 28 August to 30 September 1987 near UV zenith scattered sky measurements were made over Antarctic from the NASA DC-8 aircraft using a one third m spectrograph equipped with a diode-array detector. Scattered sky light data in the wavelength range 348 nm to 388 nm was spectrally analyzed for O3, NO2, OClO, and BrO column abundances. Slant column abudances of O3, NO2, OClO and BrO were determined, using a computer algorithm of non-linear and linear least square correlation of Antarctic scattered sky spectra to laboratory absorption cross section data. Using measured vertical electrochemical sonde ozone profiles from Palmer, Halley Bay, and the South Pole Stations the slant columns of O3 were converted into vertical column abundances. The vertical column amounts of NO2, OClO, and BrO were derived using vertical profiles calculated by a chemical model appropriate for Antarctica. NO2 vertical column abundances show steep latitudinal decrease with increasing latitude for all 13 flights carried out during the mission. In the regions where NO2 abudances are low, OClO and BrO were observed. The spatial and temporal vertical column abundances of these species are discussed in the context of the chemistry and dynamics in the antarctic polar vortex during the austral spring.

  15. 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.

  16. 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.

  17. 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.

  18. Aircraft measurement of radio frequency noise at 121.5 MHz, 243MHz and 406MHz

    NASA Technical Reports Server (NTRS)

    Taylor, R. E.; Hill, J. S.

    1977-01-01

    An airborne survey measurement of terrestrial radio-frequency noise over U.S. metropolitan areas has been made at 121.5, 243 and 406 MHz with horizontal-polarization monopole antennas. Flights were at 25,000 feet altitude during the period from December 30, 1976 to January 8, 1977. Radio-noise measurements, expressed in equivalent antenna-noise temperature, indicate a steady-background noise temperature of 572,000 K, at 121.5 MHz, during daylight over New York City. This data is helpful in compiling radio-noise temperature maps; in turn useful for designing satellite-aided, emergency-distress search and rescue communication systems.

  19. 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.

  20. 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