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Alain Marenco – One of the best experts on this subject based on the ideXlab platform.

  • MOZAIC: five in-service Airbus A340s evaluate impact of air traffic on atmosphere
    Air & Space Europe, 2000
    Co-Authors: Alain Marenco

    Abstract:

    Abstract Aircraft emissions are likely to have their greatest effect upon the atmosphere and climate when discharged near the junction of the troposphere and the stratosphere. To measure the effects of air traffic in that region of the atmosphere, a number of in-service Airbus A340 aircraft have been fitted with automatic measuring and recording equipment. Already more than 95 000 hours of observations have been recorded. This article describes this work and plans for the future.

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  • Comparison between global chemistry transport model results and Measurement of Ozone and Water Vapor by Airbus In‐Service Aircraft (MOZAIC) data
    Journal of Geophysical Research: Atmospheres, 2000
    Co-Authors: Kathy S. Law, Alain Marenco, P. H. Plantevin, Valérie Thouret, Paul J. Crutzen, W.a.h. Asman, Mark Lawrence, J.-f. Müller, D. A. Hauglustaine, Maria Kanakidou

    Abstract:

    Ozone distributions from state-of-the-art global three-dimensional chemistry transport models are compared to O 3 data collected on Airbus A340 passenger aircraft as part of the Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC) project. The model results are compared to monthly averaged data at cruise altitudes in the upper troposphere and lower stratosphere and monthly averaged vertical profiles collected over particular cities during takeoff and landing. The models generally show good agreement with the data in regions which have previously been well documented and where the meteorology is well understood/captured by meteorological models (e.g., over Europe). However, in the upper troposphere and lower stratosphere, models often fail to capture sharp gradients across the tropopause and from the subtropics to the tropics. In some models, this is related to deficiencies in model transport schemes and upper boundary conditions. Also, regions of the globe where our understanding of meteorology is poorer and emissions are less well known (e.g., tropics, continental Africa, Asia, and South America) are not simulated as well by all models. At particular measurement locations, it is apparent that emission inventories used by some global models underestimate emissions in certain regions (e.g., over southern Asia) or have incorrect seasonal variations (e.g., biomass burning over South America). Deficiencies in chemical schemes may also explain differences between models and the data.

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  • Evaluation of modeled O3 using Measurement of Ozone by Airbus In‐Service Aircraft (MOZAIC) data
    Journal of Geophysical Research: Atmospheres, 1998
    Co-Authors: Kathy S. Law, P. H. Plantevin, Dudley E Shallcross, Helen Rogers, John A. Pyle, C Grouhel, Valérie Thouret, Alain Marenco

    Abstract:

    The O 3 distribution calculated by a global three-dimensional chemistry transport model, TOMCAT, is compared to O 3 data collected on Airbus A340 passenger aircraft as part of the Measurement of Ozone by Airbus In-Service Aircraft (MOZAIC) project. The model results are compared to seasonally averaged data at cruise altitudes in the upper troposphere and lower stratosphere and to individual vertical profiles collected over particular cities during takeoff and landing. In many regions, the model shows good agreement with these data, given the large variability encountered, particularly around the tropopause. There are also significant day to day variations in ozone, which, in the vertical profile data, TOMCAT captures well over northern midlatitude cities, especially in the upper troposphere and also in the winter lower troposphere. In the tropics, the MOZAIC data often shows a lot of structure, with thin layers of high O 3 which are sometimes captured in the model. Possible reasons for this and other discrepancies are discussed.

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Ulrich Schmidt – One of the best experts on this subject based on the ideXlab platform.

  • In-situ comparison of the NO>sub>y instruments flown in MOZAIC and SPURT
    Atmospheric Chemistry and Physics, 2006
    Co-Authors: H W Patz, Andreas Volz-thomas, Michaela I. Hegglin, Dominik Brunner, H. Fischer, Ulrich Schmidt

    Abstract:

    Two aircraft instruments for the measurement of total odd nitrogen (NOy) were compared side by side aboard a Learjet A35 in April 2003 during a campaign of the AFO2000 project SPURT (Spurengastransport in der Tropopausenregion). The instruments albeit employing the same measurement principle (gold converter and chemiluminescence) had different inlet configurations. The ECO-Physics instrument operated by ETH-Zürich in SPURT had the gold converter mounted outside the aircraft, whereas the instrument operated by FZ-Jülich in the European project MOZAIC III (Measurements of ozone, water vapour, carbon monoxide and nitrogen oxides aboard Airbus A340 in-service aircraft) employed a Rosemount probe with 80 cm of FEP-tubing connecting the inlet to the gold converter. The NOy concentrations during the flight ranged between 0.3 and 3 ppb. The two data sets were compared in a blind fashion and each team followed its normal operating procedures. On average, the measurements agreed within 7%, i.e. within the combined uncertainty of the two instruments. This puts an upper limit on potential losses of HNO3 in the Rosemount inlet of the MOZAIC instrument. Larger transient deviations were observed during periods after calibrations and when the aircraft entered the stratosphere. The time lag of the MOZAIC instrument observed in these instances is in accordance with the time constant of the MOZAIC inlet line determined in the laboratory for HNO3.

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  • In-situ comparison of the NOy instruments flown in MOZAIC and SPURT
    Atmospheric Chemistry and Physics, 2006
    Co-Authors: H W Patz, Andreas Volz-thomas, Michaela I. Hegglin, Dominik Brunner, Herbert Fischer, Ulrich Schmidt

    Abstract:

    Two aircraft instruments for the measurement of total odd nitrogen (NOy) were compared side by side aboard a Learjet A35 in April 2003 during a campaign of the AFO2000 project SPURT (Spurengastransport in der Tropopausenregion). The instruments albeit employing the same measurement principle (gold converter and chemiluminescence) had different inlet configurations. The ECO-Physics instrument operated by ETH-Zurich in SPURT had the gold converter mounted outside the aircraft, whereas the instrument operated by FZ-Julich in the European project MOZAIC III (Measurements of ozone, water vapour, carbon monoxide and nitrogen oxides aboard Airbus A340 in-service aircraft) employed a Rosemount probe with 80 cm of FEP-tubing connecting the inlet to the gold converter. The NOy concentrations during the flight ranged between 0.3 and 3 ppb. The two data sets were compared in a blind fashion and each team followed its normal operating procedures. On average, the measurements agreed within 7%, i.e. within the combined uncertainty of the two instruments. This puts an upper limit on potential losses of HNO3 in the Rosemount inlet of the MOZAIC instrument. Larger transient deviations were observed during periods after calibrations and when the aircraft entered the stratosphere. The time lag of the MOZAIC instrument observed in these instances is in accordance with the time constant of the MOZAIC inlet line determined in the laboratory for HNO3.

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  • In-situ comparison of the NO<sub>y</sub> instruments flown in MOZAIC and SPURT
    Atmospheric Chemistry and Physics Discussions, 2006
    Co-Authors: H W Patz, Andreas Volz-thomas, Michaela I. Hegglin, Dominik Brunner, H. Fischer, Ulrich Schmidt

    Abstract:

    Abstract. Two aircraft instruments for the measurement of total odd nitrogen (NOy) were compared side by side aboard a Learjet A35 in April 2003 during a campaign of the AFO2000 project SPURT (Spurengastransport in der Tropopausenregion). The instruments albeit employing the same measurement principle (gold converter and chemiluminescence) had different inlet configurations. The ECO-Physics instrument operated by ETH-Zürich in SPURT had the gold converter mounted outside the aircraft, whereas the instrument operated by FZ-Jülich in the European project MOZAIC III (Measurements of ozone, water vapour, carbon monoxide and nitrogen oxides aboard Airbus A340 in-service aircraft) employed a Rosemount probe with 80 cm of FEP-tubing connecting the inlet to the gold converter. The NOy concentrations during the flight ranged between 0.3 and 3 ppb. The two data sets were compared in a blind fashion and each team followed its normal operating procedures. On average, the measurements agreed within 6%, i.e. within the combined uncertainty of the two instruments. This puts an upper limit on potential losses of HNO3 in the Rosemount inlet of the MOZAIC instrument. Larger transient deviations were observed during periods after calibrations and when the aircraft entered the stratosphere. The time lag of the MOZAIC instrument observed in these instances is in accordance with the time constant of the MOZAIC inlet line determined in the laboratory for HNO3.

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Philip Constantinou – One of the best experts on this subject based on the ideXlab platform.

  • VTC Spring – Attenuation Measurements and Interference Issues for In-Cabin Wireless Networks
    2010 IEEE 71st Vehicular Technology Conference, 2010
    Co-Authors: Nektarios Moraitis, Philip Constantinou

    Abstract:

    This paper presents an outdoor-to-aircraft measurement campaign conducted inside a long range Airbus A340-300 aircraft in order to evaluate the attenuation induced by the haul of the aircraft. The obtained results can be used to perform an interference study and assess whether the aircraft on-board network interferes to the terrestrial links. The minimum aircraft attenuation was found 15.5 dB. This value increases 5.5 dB, in average, under the wing of the aircraft. From the interference study, it is found that even from a distance of 286 km away, interference may be caused by the aircraft mobile terminal to the ground base station. If we want to prevent that the aircraft base station will interfere to the ground mobile terminal an additional shielding of 7.3 dB is required. To avoid the interference from the on-board mobile station to the ground base station an extra attenuation of about 16.3 dB is needed.

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  • Propagation measurements inside different civil aircrafts and comparison with EM techniques
    , 2009
    Co-Authors: Nektarios Moraitis, Philip Constantinou, Fernando Perez Fontan, Pavel Valtr

    Abstract:

    This paper presents results of a narrowband measurement campaign conducted in a two different civil aircrafts. Inside a Boeing 737-400 and in an Airbus A340-300 aircraft, the objective being the development of a propagation prediction model which can be used in the deployment of in-cabin wireless networks. The measurements were conducted at three different frequency bands: 1.8, 2.1 and 2.45 GHz, representative of several wireless services. The path loss factor was found between 2.1 and 2.3 inside Boeing and between 3.3 and 3.6 inside Airbus. The average K-factor in the Airbus aircraft corridors was found between 9.5 and 10.1 dB, for LoS conditions and between 3.7 and 5.0 dB for NLoS cases. In respect the K-factor inside the Boeing corridor ranges between 12.1 and 12.6 dB. Propagation prediction technique based on Physical Optics was applied to the Boeing 737-400 cabin scenario to obtain comparison of theoretically predicted values and measurements.

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  • VTC Fall – Radio Channel Measurements and Characterization inside Aircrafts for In-Cabin Wireless Networks
    2008 IEEE 68th Vehicular Technology Conference, 2008
    Co-Authors: Nektarios Moraitis, Philip Constantinou

    Abstract:

    This paper presents a measurement campaign conducted inside a large Airbus A340-300 aircraft for the development of in-cabin wireless networks. The measurements were conducted in three different frequency bands in order to provide various services. It was found that the path loss factor along the aircraft corridors varies between 2.0 and 2.7 depending on frequency. The average K-factor in the aircraft aisles was found between 9.5 and 10.1 dB, for line-of-sight (LoS) conditions, and between 3.7 and 5.0 dB for non-line-of-sight (NLoS) cases. The average dynamic range of fading varies between 12 and 14 dB for LoS, and between 25 and 28 dB for NLoS situations respectively. The maximum Doppler spread was calculated between 15 and 17 Hz, whereas the coherence time was found between 25 and 29 ms for a reference level of -3 dB.

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