scholarly journals Calibration of 3-D wind measurements on a single engine research aircraft

2015 ◽  
Vol 8 (2) ◽  
pp. 1731-1785
Author(s):  
C. Mallaun ◽  
A. Giez ◽  
R. Baumann
Keyword(s):  
Measurement Techniques ◽  
Calibration Method ◽  
Medium Size ◽  
Sideslip Angle ◽  
Airborne Measurement ◽  
Research Aircraft ◽  
Wind Measurements ◽  
Measurement Uncertainties ◽  
Coordinated Flight ◽  
Wind Speed Measurement

Abstract. 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.

scholarly journals Calibration of 3-D wind measurements on a single-engine research aircraft

2015 ◽  
Vol 8 (8) ◽  
pp. 3177-3196 ◽  
Author(s):  
C. Mallaun ◽  
A. Giez ◽  
R. Baumann
Keyword(s):  
Measurement Techniques ◽  
Three Dimensional ◽  
Calibration Method ◽  
Medium Size ◽  
Sideslip Angle ◽  
Airborne Measurement ◽  
Research Aircraft ◽  
Wind Measurements ◽  
Measurement Uncertainties ◽  
Coordinated Flight

Abstract. 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.

scholarly journals Evaluation of single and multiple Doppler lidar techniques to measure complex flow during the XPIA field campaign

2017 ◽  
Vol 10 (1) ◽  
pp. 247-264 ◽  
Author(s):  
Aditya Choukulkar ◽  
W. Alan Brewer ◽  
Scott P. Sandberg ◽  
Ann Weickmann ◽  
Timothy A. Bonin ◽  
...  
Keyword(s):  
Measurement Uncertainty ◽  
Measurement Techniques ◽  
Vertical Plane ◽  
Complex Flow ◽  
Field Campaign ◽  
Velocity Statistics ◽  
Spatial Coverage ◽  
Stable Conditions ◽  
Sonic Anemometers ◽  
Measurement Uncertainties

Abstract. Accurate three-dimensional information of wind flow fields can be an important tool in not only visualizing complex flow but also understanding the underlying physical processes and improving flow modeling. However, a thorough analysis of the measurement uncertainties is required to properly interpret results. The XPIA (eXperimental Planetary boundary layer Instrumentation Assessment) field campaign conducted at the Boulder Atmospheric Observatory (BAO) in Erie, CO, from 2 March to 31 May 2015 brought together a large suite of in situ and remote sensing measurement platforms to evaluate complex flow measurement strategies. In this paper, measurement uncertainties for different single and multi-Doppler strategies using simple scan geometries (conical, vertical plane and staring) are investigated. The tradeoffs (such as time–space resolution vs. spatial coverage) among the different measurement techniques are evaluated using co-located measurements made near the BAO tower. Sensitivity of the single-/multi-Doppler measurement uncertainties to averaging period are investigated using the sonic anemometers installed on the BAO tower as the standard reference. Finally, the radiometer measurements are used to partition the measurement periods as a function of atmospheric stability to determine their effect on measurement uncertainty. It was found that with an increase in spatial coverage and measurement complexity, the uncertainty in the wind measurement also increased. For multi-Doppler techniques, the increase in uncertainty for temporally uncoordinated measurements is possibly due to requiring additional assumptions of stationarity along with horizontal homogeneity and less representative line-of-sight velocity statistics. It was also found that wind speed measurement uncertainty was lower during stable conditions compared to unstable conditions.

scholarly journals New particle formation events measured on board the ATR-42 aircraft during the EUCAARI campaign

2010 ◽  
Vol 10 (14) ◽  
pp. 6721-6735 ◽  
Author(s):  
S. Crumeyrolle ◽  
H. E. Manninen ◽  
K. Sellegri ◽  
G. Roberts ◽  
L. Gomes ◽  
...  
Keyword(s):  
Particle Production ◽  
Size Range ◽  
Particle Formation ◽  
New Particle Formation ◽  
The North ◽  
Vertical Extension ◽  
Airborne Measurement ◽  
Ultra Fine Particle ◽  
Research Aircraft ◽  
The North Sea

Abstract. Aerosol properties were studied during an intensive airborne measurement campaign that took place at Rotterdam in Netherlands in May 2008 within the framework of the European Aerosol Cloud Climate and Air Quality Interactions project (EUCAARI). The objective of this study is to illustrate seven events of new particle formation (NPF) observed with two Condensation Particle Counters (CPCs) operated on board the ATR-42 research aircraft in airsectors around Rotterdam, and to provide information on the spatial extent of the new particle formation phenomenon based on 1-s resolution measurements of ultra-fine particle (in the size range 3–10 nm diameter, denoted N3-10 hereafter) concentrations. The results show that particle production occurred under the influence of different air mass origins, at different day times and over the North Sea as well as over the continent. The number concentration of freshly nucleated particles (N3-10) varied between 5000 and 100 000 cm−3 within the boundary layer (BL). Furthermore the vertical extension for all nucleation events observed on the ATR-42 never exceeded the upper limit of the BL. The horizontal extent of N3-10 could not be delimited due to inflexible flight plans which could not be modified to accommodate real-time results. However, the NPF events were observed over geographically large areas; typically the horizontal extension was about 100 km and larger.

Nano and Micro Mechanical Measurement of Interaction Forces Between Solid Surfaces

2006 ◽  
Vol 326-328 ◽  
pp. 1-4
Author(s):  
Kyung Suk Kim
Keyword(s):  
Scale Effects ◽  
Measurement Techniques ◽  
Calibration Method ◽  
Lateral Force ◽  
Solid Surfaces ◽  
Lateral Interaction ◽  
Force Measurements ◽  
Interaction Forces ◽  
Size Scale ◽  
Force Calibration

Two different types of experimental methods have beeen developed for measuring lateral interaction forces between two solid surfaces for nano- and micro-meter scale contacts. One is the type of direct measurement methods which typically utilize AFM instrumentations. In the direct lateral force measurements some size-scale effects are commonly observed due to the effects of adhesion and surface roughness. A recent development of a fine AFM lateral force calibration method, a diamagnetic lateral force calibrator, has made it possible to study such size-scale effects systematically. The other type is the field projection method which requires a high resolution measurement of a deformation field near the edge of a contact. For such measurements a comprehensive map of deformation measurement techniques is introduced in a domain of spatial and strain resolutions. This technique provides a way of assessing the non-uniform distribution of the surface interaction forces for nano and micro-meter scale contacts.

scholarly journals Evaluation of Single- and Multiple-Doppler Lidar Techniques to Measure Complex Flow during the XPIA Field Campaign

2016 ◽  
Author(s):  
Aditya Choukulkar ◽  
Alan Brewer ◽  
Scott P. Sandberg ◽  
Ann Weickmann ◽  
Timothy A. Bonin ◽  
...  
Keyword(s):  
Measurement Uncertainty ◽  
Measurement Techniques ◽  
Atmospheric Stability ◽  
Complex Flow ◽  
Field Campaign ◽  
Time Space ◽  
Spatial Coverage ◽  
Stable Conditions ◽  
Sonic Anemometers ◽  
Measurement Uncertainties

Abstract. Accurate three-dimensional information of wind flow fields can be an important tool in not only visualizing complex flow, but also understanding the underlying physical processes and improving flow modeling. However, a thorough analysis of the measurement uncertainties is required to properly interpret results. The XPIA (eXperimental Planetary boundary layer Instrumentation Assessment) field campaign conducted at the Boulder Atmospheric Observatory (BAO) in Erie, CO from 2 March–31 May 2015 brought together a large suite of in-situ and remote sensing measurement platforms to evaluate complex flow measurement strategies. In this paper, measurement uncertainties for different single and multi-Doppler strategies are investigated. The tradeoffs (such as time/space resolution vs. spatial coverage) among the different measurement techniques are evaluated using co-located measurements made near the BAO tower. Sensitivity of the single/multi Doppler measurement uncertainties to averaging period are investigated using the sonic anemometers installed on the BAO tower as the standard reference. Finally, the radiometer measurements are used to partition the measurement periods as a function of atmospheric stability to determine their effect on measurement uncertainty. It was found that with increase in spatial coverage and measurement complexity, the uncertainty in the wind measurement also increased. For multi-Doppler techniques, the increase in uncertainty for temporally uncoordinated measurements is possibly due to requiring additional assumptions of stationarity and/or horizontal homogeneity. It was also found that wind speed measurement uncertainty was lower during stable conditions compared to unstable conditions.

scholarly journals Airborne tests of an OAWL Doppler lidar: Results and potential for space deployment

2018 ◽  
Vol 176 ◽  
pp. 02004
Author(s):  
Michael Hardesty ◽  
Sara Tucker ◽  
Sunil Baidar ◽  
Mark Beubien
Keyword(s):  
Instrument Design ◽  
Doppler Lidar ◽  
Atmospheric Models ◽  
Wind Measurement ◽  
Measurement Capability ◽  
Research Aircraft ◽  
Wind Measurements ◽  
Wind Lidar ◽  
532 Nm ◽  
Good Agreement

The 532 nm Green Optical Covariance Wind Lidar (GrOAWL) was flown on a NASA WB-57 research aircraft during the summer of 2016 to validate the instrument design and evaluate wind measurement capability and sensitivity. Comparisons with dropsondes and atmospheric models showed good agreement, demonstrating that a GrOAWL type instrument could provide high-value wind measurements from both airborne and space-based platforms

scholarly journals Uncertainty Analysis of Fluorescence-Based Oil-In-Water Monitors for Oil and Gas Produced Water

Sensors ◽  
2020 ◽  
Vol 20 (16) ◽  
pp. 4435 ◽  
Author(s):  
Dennis Severin Hansen ◽  
Stefan Jespersen ◽  
Mads Valentin Bram ◽  
Zhenyu Yang
Keyword(s):  
Oil And Gas ◽  
Produced Water ◽  
Separation Efficiency ◽  
Measurement Techniques ◽  
High Sensitivity ◽  
Calibration Method ◽  
Least Square ◽  
Oil In Water ◽  
Before And After ◽  
The Government

Offshore oil and gas facilities are currently measuring the oil-in-water (OiW) concentration in the produced water manually before discharging it into the ocean, which in most cases fulfills the government regulations. However, as stricter regulations and environmental concerns are increasing over time, the importance of measuring OiW in real-time intensifies. The significant amount of uncertainties associated with manual samplings, that is currently not taken into consideration, could potentially affect the acceptance of OiW monitors and lower the reputation of all online OiW measurement techniques. This work presents the performance of four fluorescence-based monitors on an in-house testing facility. Previous studies of a fluorescence-based monitor have raised concerns about the measurement of OiW concentration being flow-dependent. The proposed results show that the measurements from the fluorescence-based monitors are not or insignificantly flow-dependent. However, other parameters, such as gas bubbles and droplet sizes, do affect the measurement. Testing the monitors’ calibration method revealed that the weighted least square is preferred to achieve high reproducibility. Due to the high sensitivity to different compositions of atomic structures, other than aromatic hydrocarbons, the fluorescence-based monitor might not be feasible for measuring OiW concentrations in dynamic separation facilities with consistent changes. Nevertheless, they are still of interest for measuring the separation efficiency of a deoiling hydrocyclone to enhance its deoiling performance, as the separation efficiency is not dependent on OiW trueness but rather the OiW concentration before and after the hydrocyclone.

scholarly journals The airborne mass spectrometer AIMS – Part 2: Measurements of trace gases with stratospheric or tropospheric origin in the UTLS

2016 ◽  
Vol 9 (4) ◽  
pp. 1907-1923 ◽  
Author(s):  
Tina Jurkat ◽  
Stefan Kaufmann ◽  
Christiane Voigt ◽  
Dominik Schäuble ◽  
Philipp Jeßberger ◽  
...  
Keyword(s):  
Nitrogen Oxide ◽  
Mass Spectrometer ◽  
Chemical Ionization ◽  
Trace Gases ◽  
Measurement Techniques ◽  
Ion Source ◽  
Trace Gas ◽  
Ionization Mass ◽  
Custom Made ◽  
Research Aircraft

Abstract. Understanding the role of climate-sensitive trace gas variabilities in the upper troposphere and lower stratosphere region (UTLS) and their impact on its radiative budget requires accurate measurements. The composition of the UTLS is governed by transport and chemistry of stratospheric and tropospheric constituents, such as chlorine, nitrogen oxide and sulfur compounds. The Atmospheric chemical Ionization Mass Spectrometer AIMS has been developed to accurately measure a set of these constituents on aircraft by means of chemical ionization. Here we present a setup using SF5− reagent ions for the simultaneous measurement of trace gas concentrations of HCl, HNO3 and SO2 in the  pptv to ppmv (10−12 to 10−6 mol mol−1) range with in-flight and online calibration called AIMS-TG (Atmospheric chemical Ionization Mass Spectrometer for measurements of trace gases). Part 1 of this paper (Kaufmann et al., 2016) reports on the UTLS water vapor measurements with the AIMS-H2O configuration. The instrument can be flexibly switched between two configurations depending on the scientific objective of the mission. For AIMS-TG, a custom-made gas discharge ion source has been developed for generation of reagent ions that selectively react with HCl, HNO3, SO2 and HONO. HNO3 and HCl are routinely calibrated in-flight using permeation devices; SO2 is continuously calibrated during flight adding an isotopically labeled 34SO2 standard. In addition, we report on trace gas measurements of HONO, which is sensitive to the reaction with SF5−. The detection limit for the various trace gases is in the low 10 pptv range at a 1 s time resolution with an overall uncertainty of the measurement of the order of 20 %. AIMS has been integrated and successfully operated on the DLR research aircraft Falcon and HALO (High Altitude LOng range research aircraft). As an example, measurements conducted during the TACTS/ESMVal (Transport and Composition of the LMS/UT and Earth System Model Validation) mission with HALO in 2012 are presented, focusing on a classification of tropospheric and stratospheric influences in the UTLS region. The combination of AIMS measurements with other measurement techniques yields a comprehensive picture of the sulfur, chlorine and reactive nitrogen oxide budget in the UTLS. The different trace gases measured with AIMS exhibit the potential to gain a better understanding of the trace gas origin and variability at and near the tropopause.

scholarly journals Past changes in the vertical distribution of ozone – Part 1: Measurement techniques, uncertainties and availability

2014 ◽  
Vol 7 (5) ◽  
pp. 1395-1427 ◽  
Author(s):  
B. Hassler ◽  
I. Petropavlovskikh ◽  
J. Staehelin ◽  
T. August ◽  
P. K. Bhartia ◽  
...  
Keyword(s):  
Stratospheric Ozone ◽  
Measurement Techniques ◽  
United Nations Environment Programme ◽  
Critical Examination ◽  
Profile Measurement ◽  
Data Sets ◽  
Data Set ◽  
Ozone Profile ◽  
Measurement Uncertainties

Abstract. Peak stratospheric chlorofluorocarbon (CFC) and other ozone depleting substance (ODS) concentrations were reached in the mid- to late 1990s. Detection and attribution of the expected recovery of the stratospheric ozone layer in an atmosphere with reduced ODSs as well as efforts to understand the evolution of stratospheric ozone in the presence of increasing greenhouse gases are key current research topics. These require a critical examination of the ozone changes with an accurate knowledge of the spatial (geographical and vertical) and temporal ozone response. For such an examination, it is vital that the quality of the measurements used be as high as possible and measurement uncertainties well quantified. In preparation for the 2014 United Nations Environment Programme (UNEP)/World Meteorological Organization (WMO) Scientific Assessment of Ozone Depletion, the SPARC/IO3C/IGACO-O3/NDACC (SI2N) Initiative was designed to study and document changes in the global ozone profile distribution. This requires assessing long-term ozone profile data sets in regards to measurement stability and uncertainty characteristics. The ultimate goal is to establish suitability for estimating long-term ozone trends to contribute to ozone recovery studies. Some of the data sets have been improved as part of this initiative with updated versions now available. This summary presents an overview of stratospheric ozone profile measurement data sets (ground and satellite based) available for ozone recovery studies. Here we document measurement techniques, spatial and temporal coverage, vertical resolution, native units and measurement uncertainties. In addition, the latest data versions are briefly described (including data version updates as well as detailing multiple retrievals when available for a given satellite instrument). Archive location information for each data set is also given.

Improved Wind Measurements on Research Aircraft

1999 ◽  
Vol 16 (7) ◽  
pp. 860-875 ◽  
Author(s):  
D. Khelif ◽  
S. P. Burns ◽  
C. A. Friehe
Keyword(s):  
Research Aircraft ◽  
Wind Measurements
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