Science.gov

Sample records for aircraft in-situ measurements

  1. 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.

  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. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  5. Air-Sea Fluxes in Terra Nova Bay, Antarctica from In Situ Aircraft Measurements

    NASA Astrophysics Data System (ADS)

    Knuth, S. L.; Cassano, J. J.

    2011-12-01

    In September 2009, the first unmanned aerial vehicles (UAVs) were flown over Terra Nova Bay, Antarctica to collect information regarding air-sea interactions over a wintertime coastal polynya. The UAVs measured wind, temperature, pressure, and relative humidity in flights parallel to the downslope wind flow over the polynya, and in a series of vertical profiles at varying distances from the coast. During three flights on three different days, sufficient measurements were collected to calculate sensible heat, latent heat, and momentum fluxes over varying oceanic surface states, including frazil, pancake, and rafted ice, with background winds greater than 15 ms-1. During the three flights, sensible heat fluxes upwards of 600 Wm-2 were estimated near the coast, with maximum latent heat fluxes near 160 Wm-2 just downwind of the coast. The calculated accelerations due to the momentum flux divergence were on the order of 10-3 ms-2. In addition to the fluxes, changes in the overall momentum budget, including the horizontal pressure gradient force, were also calculated during the three flights. This presentation will summarize the methodology for calculating the fluxes from the UAV data, present the first ever in situ estimates of sensible heat, latent heat, and momentum fluxes and overall momentum budget estimates over Terra Nova Bay, and compare the UAV flux calculations to flux measurements taken during other field campaigns in other regions of the Antarctic, as well as to model estimates over Terra Nova Bay.

  6. Tunable diode laser in-situ CH4 measurements aboard the CARIBIC passenger aircraft: instrument performance assessment

    NASA Astrophysics Data System (ADS)

    Dyroff, C.; Zahn, A.; Sanati, S.; Christner, E.; Rauthe-Schöch, A.; Schuck, T. J.

    2014-03-01

    A laser spectrometer for automated monthly measurements of methane (CH4) mixing ratios aboard the CARIBIC passenger aircraft is presented. The instrument is based on a commercial Fast Greenhouse Gas Analyser (FGGA, Los Gatos Res.), which was adapted to meet the requirements imposed by unattended airborne operation. It was characterised in the laboratory with respect to instrument stability, precision, cross sensitivity to H2O, and accuracy. For airborne operation, a calibration strategy is described that utilises CH4 measurements obtained from flask samples taken during the same flights. The precision of airborne measurements is 2 ppb for 10 s averages. The accuracy at aircraft cruising altitude is 3.85 ppb. During aircraft ascent and descent, where no flask samples were obtained, instrumental drifts can be less accurately determined and the uncertainty is estimated to be 12.4 ppb. A linear humidity bias correction was applied to the CH4 measurements, which was most important in the lower troposphere. On average, the correction bias was around 6.5 ppb at an altitude of 2 km, and negligible at cruising flight level. Observations from 103 long-distance flights are presented that span a large part of the northern hemispheric upper troposphere and lowermost stratosphere (UT/LMS), with occasional crossing of the tropics on flights to southern Africa. These accurate data mark the largest UT/LMS in-situ CH4 dataset worldwide. An example of a tracer-tracer correlation study with ozone is given, highlighting the possibility for accurate cross-tropopause transport analyses.

  7. Tunable diode laser in-situ CH4 measurements aboard the CARIBIC passenger aircraft: instrument performance assessment

    NASA Astrophysics Data System (ADS)

    Dyroff, C.; Zahn, A.; Sanati, S.; Christner, E.; Rauthe-Schöch, A.; Schuck, T. J.

    2013-10-01

    A laser spectrometer for automated monthly measurements of methane (CH4) mixing ratios aboard the CARIBIC passenger aircraft is presented. The instrument is based on a commercial Fast Greenhouse Gas Analyzer (FGGA, Los Gatos Res.), which was adapted to meet the requirements imposed by unattended airborne employment. The modified instrument is described. A laboratory characterization was performed to determine the instrument stability, precision, cross sensitivity to H2O, and accuracy. For airborne operation a calibration strategy is described, that utilizes CH4 measurements obtained from flask samples taken during the same flights. The precision of airborne measurements is 2 ppbv for 10 s averages. The accuracy at aircraft cruising altitude is 3.85 ppbv. During aircraft ascent and descent, where no flask samples were obtained, instrumental drifts can be less accurately considered and the uncertainty is estimated to be 12.4 ppbv. A linear humidity bias correction was applied to the CH4 measurements, which was most important in the lower troposphere. On average, the correction bias was around 6.5 ppbv at an altitude of 2 km, and negligible at cruising flight level. Observations from 103 long-distance flights are presented that span a large part of the northern hemispheric upper troposphere and lowermost stratosphere (UT/LMS), with occasional crossing of the tropics on flights to southern Africa. These accurate data mark the largest UT/LMS in-situ CH4 dataset worldwide. An example of a tracer-tracer correlation study with ozone is given, highlighting the possibility for accurate cross-tropopause transport analyses.

  8. Vortex dynamics behind cruising aircraft studied by a ground-based scanning lidar and airborne in-situ measurements

    NASA Astrophysics Data System (ADS)

    Sussmann, Ralf; Jaeger, Horst

    1997-05-01

    By LIDAR and CCD camera analysis the geometrical evolution of a vortex phase contrail (descent rate Vd equals 2.7 m/s, vortex separation D equals 47 m, vertical extension (sigma) z equals 140 m after 77 s) is analyzed. The contrail of a four-engine aircraft is showing a diffuse central wake phenomenon. From coincident in situ measurements all relevant meteorological parameters are characterized. Ambient humidity had been close to ice saturation. From this a non-exhaust formation of ice can be excluded. Also the mechanism of non- entrainment of exhaust into the vortices is excluded of being responsible for the observed early onset of the central wake (870 m behind aircraft). The central wake onset originates from early detrainment starting after a 3/4 roll-up period of the vortex. Baroclinic and shear forces do not contribute to the detrainment (imaginary Brunt-Vaisala-frequency N2 equals negative 3 multiplied by 10-5 s-2, shear dS/dz equals negative 0.01 s-1, bulk Richardson number Ri, equals N2/(dS/dz)2 equals negative 0.3). Ambient turbulence had been fully developed with an inertial range and locally isotropic turbulence for wavenumbers k-equals 0.004 - 0.1 radian/m. The eddy dissipation rate (epsilon) equals 7.4 plus or minus 0.5 multiplied by 10-5 m2s-3 exceeds the values found over the North Atlantic flight corridor at cruising altitude by a factor of 1000. Turbulence was identified as the dominating detrainment mechanism.

  9. 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.

  10. Variability of aerosol optical properties derived from in situ aircraft measurements during ACE-Asia

    NASA Astrophysics Data System (ADS)

    Anderson, Theodore L.; Masonis, Sarah J.; Covert, David S.; Ahlquist, Norman C.; Howell, Steven G.; Clarke, Antony D.; McNaughton, Cameron S.

    2003-12-01

    Airborne measurements of aerosol light scattering (using nephelometers) and absorption (using particle/soot absorption photometers; PSAPs) in the Asian outflow region are presented. Aerosol particles were sampled through a new low turbulence inlet that proved very effective at transmitting coarse-mode particles. Noise and artifacts are characterized using in-flight measurements of particle-free air and measurements with identical instruments operated in parallel. For example, the sensitivities of PSAP noise to changing altitude, changing relative humidity (RH), and particle-loading on the internal filter are quantified. On the basis of these and previous instrument characterizations, we report averages, variations, and uncertainties of optical properties, focusing on data from approximately 300 level-leg samples obtained during 19 research flights in the spring of 2001. Several broad patterns emerge from this analysis. Two dominant components, fine-mode pollution and coarse-mode mineral dust, were observed to vary independently when separated using a cut point of 1 μm aerodynamic diameter at low RH. Fine-mode pollution was found to be moderately absorbing (single scatter albedo at low RH and 550 nm, ω = 0.88 ± 0.03; mean and 95% confidence uncertainty) and moderately hygroscopic (relative increase in scattering from 40% to 85% RH, fRH = 1.7 ± 0.2), while coarse-mode dust was found to have very low absorption (ω = 0.96 ± 0.01) and to be almost nonhygroscopic (fRH = 1.1 ± 0.1). These and other optical properties are intended to serve as constraints on optical models of the Asian aerosol for the purpose of satellite retrievals and calculations of direct radiative effects.

  11. 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.

  12. In situ measurement system

    DOEpatents

    Lord, D.E.

    1980-11-24

    A multipurpose in situ underground measurement system comprising a plurality of long electrical resistance elements in the form of rigid reinforcing bars, each having an open loop hairpin configuration of shorter length than the other resistance elements. The resistance elements are arranged in pairs in a unitized structure, and grouted in place in the underground volume. Measurement means are provided for obtaining for each pair the electrical resistance of each element and the difference in electrical resistance of the paired elements, which difference values may be used in analytical methods involving resistance as a function of temperature. A scanner means sequentially connects the resistance-measuring apparatus to each individual pair of elements. A source of heating current is also selectively connectable for heating the elements to an initial predetermined temperature prior to electrical resistance measurements when used as an anemometer.

  13. Study of aerosol microphysical properties profiles retrieved from ground-based remote sensing and aircraft in-situ measurements during a Saharan dust event

    NASA Astrophysics Data System (ADS)

    Granados-Muñoz, M. J.; Bravo-Aranda, J. A.; Baumgardner, D.; Guerrero-Rascado, J. L.; Pérez-Ramírez, D.; Navas-Guzmán, F.; Veselovskii, I.; Lyamani, H.; Valenzuela, A.; Olmo, F. J.; Titos, G.; Andrey, J.; Chaikovsky, A.; Dubovik, O.; Gil-Ojeda, M.; Alados-Arboledas, L.

    2015-09-01

    In this work we present an analysis of mineral dust optical and microphysical properties obtained from different retrieval techniques applied to active and passive remote sensing measurements, including a comparison with simultaneous in-situ aircraft measurements. Data were collected in a field campaign performed during a mineral dust outbreak a Granada, Spain, experimental site (37.16° N, 3.61° W, 680 m a.s.l.) on the 27 June 2011. Column-integrated properties are provided by sun- and star-photometry which allows a continuous evaluation of the mineral dust optical properties during both day and night-time. Both the Linear Estimation and AERONET (Aerosol Robotic Network) inversion algorithms are applied for the retrieval of the column-integrated microphysical particle properties. In addition, vertically-resolved microphysical properties are obtained from a multi-wavelength Raman lidar system included in EARLINET (European Aerosol Research Lidar Network), by using both LIRIC (Lidar Radiometer Inversion Code) algorithm during daytime and an algorithm applied to the Raman measurements based on the regularization technique during night-time. LIRIC retrievals reveal several dust layers between 3 and 5 km a.s.l. with volume concentrations of the coarse spheroid mode up to 60 μm3 cm-3. The combined use of the regularization and LIRIC methods reveals the night-to-day evolution of the vertical structure of the mineral dust microphysical properties and offers complementary information to that from column-integrated variables retrieved from passive remote sensing. Additionally, lidar depolarization profiles and LIRIC retrieved volume concentration are compared with aircraft in-situ measurements. This study presents for the first time a comparison of both volume concentration and dust particle polarization ratios measured with in-situ and remote sensing techniques. Results for the depolarization measurements in the dust layer indicate reasonable agreement within the

  14. Aircraft measurements of bromine monoxide, iodine monoxide, and glyoxal profiles in the tropics: comparison with ship-based and in situ measurements

    NASA Astrophysics Data System (ADS)

    Volkamer, R.; Baidar, S.; Campos, T. L.; Coburn, S.; DiGangi, J. P.; Dix, B.; Koenig, T. K.; Ortega, I.; Pierce, B. R.; Reeves, M.; Sinreich, R.; Wang, S.; Zondlo, M. A.; Romashkin, P. A.

    2015-01-01

    Tropospheric chemistry of halogens and organic carbon over tropical oceans modifies ozone and atmospheric aerosols, yet atmospheric models remain largely untested for lack of vertically resolved measurements of bromine monoxide (BrO), iodine monoxide (IO), and small oxygenated hydrocarbons like glyoxal (CHOCHO) in the tropical troposphere. BrO, IO, glyoxal, nitrogen dioxide (NO2), water vapor (H2O) and O2-O2 collision complexes (O4) were measured by the CU Airborne Multi AXis Differential Optical Absorption Spectroscopy (CU AMAX-DOAS) instrument, in situ aerosol size distributions by an Ultra High Sensitivity Aerosol Spectrometer (UHSAS), and in situ H2O by Vertical-Cavity Surface-Emitting Laser hygrometer (VCSEL). Data are presented from two research flights (RF12, RF17) aboard the NSF/NCAR GV aircraft over the tropical Eastern Pacific Ocean (tEPO) as part of the "Tropical Ocean tRoposphere Exchange of Reactive halogens and Oxygenated hydrocarbons" (TORERO) project. We assess the accuracy of O4 slant column density (SCD) measurements in the presence and absence of aerosols, and find O4-inferred aerosol extinction profiles at 477 nm agree within 5% with Mie calculations of extinction profiles constrained by UHSAS. CU AMAX-DOAS provides a flexible choice of geometry which we exploit to minimize the SCD in the reference spectrum (SCDREF, maximize signal-to-noise), and to test the robustness of BrO, IO, and glyoxal differential SCDs. The RF12 case study was conducted in pristine marine and free tropospheric air. The RF17 case study was conducted above the NOAA RV Ka'imimoana (TORERO cruise, KA-12-01), and provides independent validation data from ship-based in situ Cavity Enhanced- and MAX-DOAS. Inside the marine boundary layer (MBL) no BrO was detected (smaller than 0.5 pptv), and 0.2-0.55 pptv IO and 32-36 pptv glyoxal were observed. The near surface concentrations agree within 20% (IO) and 10% (glyoxal) between ship and aircraft. The BrO concentration strongly

  15. A comparative study of aerosol microphysical properties retrieved from ground-based remote sensing and aircraft in situ measurements during a Saharan dust event

    NASA Astrophysics Data System (ADS)

    José Granados-Muñoz, María; Bravo-Aranda, Juan Antonio; Baumgardner, Darrel; Guerrero-Rascado, Juan Luis; Pérez-Ramírez, Daniel; Navas-Guzmán, Francisco; Veselovskii, Igor; Lyamani, Hassan; Valenzuela, Antonio; José Olmo, Francisco; Titos, Gloria; Andrey, Javier; Chaikovsky, Anatoli; Dubovik, Oleg; Gil-Ojeda, Manuel; Alados-Arboledas, Lucas

    2016-03-01

    In this work we present an analysis of aerosol microphysical properties during a mineral dust event taking advantage of the combination of different state-of-the-art retrieval techniques applied to active and passive remote sensing measurements and the evaluation of some of those techniques using independent data acquired from in situ aircraft measurements. Data were collected in a field campaign performed during a mineral dust outbreak at the Granada, Spain, experimental site (37.16° N, 3.61° W, 680 m a.s.l.) on 27 June 2011. Column-integrated properties are provided by sun- and star-photometry, which allows for a continuous evaluation of the mineral dust optical properties during both day and nighttime. Both the linear estimation and AERONET (Aerosol Robotic Network) inversion algorithms are applied for the retrieval of the column-integrated microphysical particle properties. In addition, vertically resolved microphysical properties are obtained from a multi-wavelength Raman lidar system included in EARLINET (European Aerosol Research Lidar Network), by using both LIRIC (Lidar Radiometer Inversion Code) algorithm during daytime and an algorithm applied to the Raman measurements based on the regularization technique during nighttime. LIRIC retrievals reveal the presence of dust layers between 3 and 5 km a.s.l. with volume concentrations of the coarse spheroid mode up to 60 µm3 cm-3. The combined use of the regularization and LIRIC methods reveals the night-to-day evolution of the vertical structure of the mineral dust microphysical properties and offers complementary information to that from column-integrated variables retrieved from passive remote sensing. Additionally, lidar depolarization profiles and LIRIC retrieved volume concentration are compared with aircraft in situ measurements. This study presents for the first time a comparison of the total volume concentration retrieved with LIRIC with independent in situ measurements, obtaining agreement within

  16. Remote versus in situ turbulence measurements

    NASA Technical Reports Server (NTRS)

    Frost, Walter

    1987-01-01

    Comparisons of in situ wind and turbulence measurements made with the NASA B-57 instrumented aircraft and those remotely made with both radar and lidar systems are presented. Turbulence measurements with a lidar or radar system as compared with those from an aircraft are the principal themes. However, some discussion of mean wind speed and direction measurements is presented. First, the principle of measuring turbulence with Doppler lidar and radar is briefly and conceptually described. The comparisons with aircraft measurements are then discussed. Two studies in particular are addressed: one uses the JAWS Doppler radar data and the other uses data gathered both with the NASA Marshall Space Flight Center and the the NOAA Wave Propagation Lab. gound based lidars. Finally, some conclusions and recommendations are made.

  17. In-situ measurements of chlorine activation, nitric acid redistribution and ozone depletion in the Antarctic lower vortex aboard the German research aircraft HALO during TACTS/ESMVal

    NASA Astrophysics Data System (ADS)

    Jurkat, Tina; Voigt, Christiane; Kaufmann, Stefan; Schlage, Romy; Gottschaldt, Klaus-Dirk; Ziereis, Helmut; Hoor, Peter; Bozem, Heiko; Müller, Stefan; Zahn, Andreas; Schlager, Hans; Oelhaf, Hermann; Sinnhuber, Björn-Martin; Dörnbrack, Andreas

    2016-04-01

    In-situ measurements of stratospheric chlorine compounds are rare and exhibit the potential to gain insight into small scale mixing processes where stratospheric air masses of different origin and history interact. In addition, the relationship with chemically stable trace gases helps to identify regions that have been modified by chemical processing on polar stratospheric clouds. To this end, in-situ measurements of ClONO2, HCl, HNO3, NOy, N2O and O3 have been performed in the Antarctic Polar Vortex in September 2012 aboard the German research aircraft HALO (High Altitude and Long Rang research aircraft) during the TACTS/ESMVal (Transport and Composition in the UTLS/Earth System Model Validation) mission. With take-off and landing in Capetown, HALO sampled vortex air with latitudes down to 65°S, at altitudes between 8 and 14.3 km and potential temperatures between 340 and 390 K. Before intering the vortex at 350 K potential temperature, HALO additionally sampled mid-latitude stratospheric air. The trace gas distributions at the edge of the Antarctic polar vortex show distinct signatures of processed upper stratospheric vortex air and chemically different lower stratospheric / upper tropospheric air. Diabatic descend of the vortex transports processed air into the lower stratosphere. Here small scale filaments of only a few kilometers extension form at the lower vortex boundary due to shear stress, ultimately leading to transport and irreversible mixing. Comparison of trace gas relationships with those at the beginning of the polar winter reveals substantial chlorine activation, ozone depletion de- and renitrification with high resolution. Furthermore, the measurements are compared to the chemistry climate models EMAC and supported by ECMWF analysis. Finally, we compare the Antarctic measurements with new measurements of ClONO2, HCl and HNO3 aboard HALO obtained during the Arctic mission POLSTRACC (POLar STratosphere in a Changing Climate) based in Kiruna (Sveden

  18. Comparison and statistics of aerosol properties measured in situ in the tropopause region during the aircraft campaigns of POLSTAR, LACE 98, UFA, EXPORT, INCA and SCAVEX

    NASA Astrophysics Data System (ADS)

    Minikin, A.; Petzold, A.; Fiebig, M.; Hendricks, J.; Schröder, F.; Schlager, H.

    2003-04-01

    In the past few years the DLR Falcon 20, a German twin-jet research aircraft with a maximum ceiling of 13~km, has participated in a number of experiments devoted to the characterization of aerosol properties in the troposphere and the tropopause region. Total aerosol number concentrations for Aitken mode and ultrafine particles have been measured with condensation particle counters with different lower cut-off diameters in the range from 3 to 15~nm. For a subset of data, the fractionation between volatile, semi-volatile and refractory particles was determined. Total concentration of accumulation mode particles as well as aerosol size distributions were determined from measurements of a combination of optical aerosol spectrometer probes (PMS PCASP-100X and FSSP-300). In this contribution we report on mean tropospheric vertical profiles of aerosol properties and the statistics of aerosol abundance and size distributions in the upper troposphere for different campaigns mainly conducted in Europe but with differing continental character. Results of the projects LACE~98, UFA, EXPORT and SCAVEX refer to measurements over Germany and neighboring countries in spring, summer and autumn. Contrasting geographical regions are addressed by the results of the POLSTAR and INCA campaigns (high latitudes of the northern hemisphere and mid-latitudes of the southern and northern hemisphere, respectively, the latter with only small continental influence). We compare the results of the different campaigns in order to assess the representativity and natural variability of aerosol properties measured in situ in the upper troposphere and in the transition to the lower stratosphere. Experimental results are compared to simulations of the ECHAM global climate model. Simulated aerosol mass concentrations are in good agreement with observations of the mean vertical distribution of accumulation mode particles and the contrasting concentration level in the northern and southern hemisphere mid-latitudes.

  19. In situ measurements of particulate number density and size distribution from an aircraft. [using light scattering particle counter

    NASA Technical Reports Server (NTRS)

    Briehl, D.

    1974-01-01

    Two different 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 micron in diameter. A specially designed pressurization system was used with this 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 microns and greater in diameter. Considerable variation in number density was encountered for both classes of particles at the test altitudes ranging from 5 to 12 km. Presence of clouds could be detected by the light scattering instrument because large numbers of particles would then be registered by the instrument, especially in the size range above 5.0 microns in diameter.

  20. 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%).

  1. Aircraft Measurements of BrO, IO, Glyoxal, NO2, H2O, O2-O2 and Aerosol Extinction Profiles in the Tropics: Comparison with Aircraft-/Ship-Based in Situ and Lidar Measurements

    NASA Technical Reports Server (NTRS)

    Volkamer, R.; Baidar, S.; Campos, T. L.; Coburn, S.; DiGangi, J. P.; Dix, B.; Eloranta, E. W.; Koenig, T. K.; Morley, B.; Ortega, I.; Pierce, B. R.; Reeves, M.; Sinreich, R.; Wang, S.; Zondlo, M. A.; Romashkin, P. A.

    2015-01-01

    Tropospheric chemistry of halogens and organic carbon over tropical oceans modifies ozone and atmospheric aerosols, yet atmospheric models remain largely untested for lack of vertically resolved measurements of bromine monoxide (BrO), iodine monoxide (IO) and small oxygenated hydrocarbons like glyoxal (CHOCHO) in the tropical troposphere. BrO, IO, glyoxal, nitrogen dioxide (NO2), water vapor (H2O) and O2-O2 collision complexes (O4/ were measured by the University of Colorado Airborne Multi-AXis Differential Optical Absorption Spectroscopy (CU AMAXDOAS) instrument, aerosol extinction by high spectral resolution lidar (HSRL), in situ aerosol size distributions by an ultra high sensitivity aerosol spectrometer (UHSAS) and in situ H2O by vertical-cavity surface-emitting laser (VCSEL) hygrometer. Data are presented from two research flights (RF12, RF17) aboard the National Science Foundation/ National Center for Atmospheric Research Gulfstream V aircraft over the tropical Eastern Pacific Ocean (tEPO) as part of the "Tropical Ocean tRoposphere Exchange of Reactive halogens and Oxygenated hydrocarbons" (TORERO) project (January/February 2012). We assess the accuracy of O4 slant column density (SCD) measurements in the presence and absence of aerosols. Our O4-inferred aerosol extinction profiles at 477 nm agree within 6% with HSRL in the boundary layer and closely resemble the renormalized profile shape of Mie calculations constrained by UHSAS at low (sub-Rayleigh) aerosol extinction in the free troposphere. CU AMAX-DOAS provides a flexible choice of geometry, which we exploit to minimize the SCD in the reference spectrum (SCDREF, maximize signal-to-noise ratio) and to test the robustness of BrO, IO and glyoxal differential SCDs. The RF12 case study was conducted in pristine marine and free tropospheric air. The RF17 case study was conducted above the NOAA RV Ka'imimoana (TORERO cruise, KA-12-01) and provides independent validation data from ship-based in situ cavity

  2. Aircraft measurements of BrO, IO, glyoxal, NO2, H2O, O2-O2 and aerosol extinction profiles in the tropics: comparison with aircraft-/ship-based in situ and lidar measurements

    NASA Astrophysics Data System (ADS)

    Volkamer, R.; Baidar, S.; Campos, T. L.; Coburn, S.; DiGangi, J. P.; Dix, B.; Eloranta, E. W.; Koenig, T. K.; Morley, B.; Ortega, I.; Pierce, B. R.; Reeves, M.; Sinreich, R.; Wang, S.; Zondlo, M. A.; Romashkin, P. A.

    2015-05-01

    Tropospheric chemistry of halogens and organic carbon over tropical oceans modifies ozone and atmospheric aerosols, yet atmospheric models remain largely untested for lack of vertically resolved measurements of bromine monoxide (BrO), iodine monoxide (IO) and small oxygenated hydrocarbons like glyoxal (CHOCHO) in the tropical troposphere. BrO, IO, glyoxal, nitrogen dioxide (NO2), water vapor (H2O) and O2-O2 collision complexes (O4) were measured by the University of Colorado Airborne Multi-AXis Differential Optical Absorption Spectroscopy (CU AMAX-DOAS) instrument, aerosol extinction by high spectral resolution lidar (HSRL), in situ aerosol size distributions by an ultra high sensitivity aerosol spectrometer (UHSAS) and in situ H2O by vertical-cavity surface-emitting laser (VCSEL) hygrometer. Data are presented from two research flights (RF12, RF17) aboard the National Science Foundation/National Center for Atmospheric Research Gulfstream V aircraft over the tropical Eastern Pacific Ocean (tEPO) as part of the "Tropical Ocean tRoposphere Exchange of Reactive halogens and Oxygenated hydrocarbons" (TORERO) project (January/February 2012). We assess the accuracy of O4 slant column density (SCD) measurements in the presence and absence of aerosols. Our O4-inferred aerosol extinction profiles at 477 nm agree within 6% with HSRL in the boundary layer and closely resemble the renormalized profile shape of Mie calculations constrained by UHSAS at low (sub-Rayleigh) aerosol extinction in the free troposphere. CU AMAX-DOAS provides a flexible choice of geometry, which we exploit to minimize the SCD in the reference spectrum (SCDREF, maximize signal-to-noise ratio) and to test the robustness of BrO, IO and glyoxal differential SCDs. The RF12 case study was conducted in pristine marine and free tropospheric air. The RF17 case study was conducted above the NOAA RV Ka'imimoana (TORERO cruise, KA-12-01) and provides independent validation data from ship-based in situ cavity

  3. In-situ measurement system

    DOEpatents

    Lord, David E.

    1983-01-01

    A multipurpose in situ underground measurement system comprising a plurality of long electrical resistance elements in the form of rigid reinforcing bars, each having an open loop "hairpin" configuration of shorter length than the other resistance elements. The resistance elements are arranged in pairs in a unitized structure, and grouted in place in the underground volume. The electrical resistance of each element and the difference in electrical resistance of the paired elements are obtained, which difference values may be used in analytical methods involving resistance as a function of temperature. A scanner sequentially connects the resistance-measuring apparatus to each individual pair of elements. A source of heating current is also selectively connectable for heating the elements to an initial predetermined temperature prior to electrical resistance measurements when used as an anemometer.

  4. In situ aircraft verification of the quality of satellite cloud winds over oceanic regions

    NASA Technical Reports Server (NTRS)

    Hasler, A. F.; Skillman, W. C.; Shenk, W. E.; Steranka, J.

    1979-01-01

    A 5-year aircraft experiment to verify the quality of satellite cloud winds over oceans using in situ aircraft Inertial Navigation System wind measurements is presented. Cloud motions measured by satellite and aircraft wind measurements that were coincident in time and space, and the results from the experiment are for undisturbed to moderately disturbed oceanic weather regimes. The results show that satellite measured cumulus cloud motions are good estimators of the cloud-base wind for trade wind and subtropical high regions. The average magnitude of the vector differences between the cloud motion and the cloud-base wind was determined; for cumulus clouds near frontal regions, the cloud motions agreed best with the mean cloud layer wind. For a very limited sample, cirrus cloud motions most closely followed the mean wind in the cloud layer.

  5. Wind estimates from cloud motions - Phase 1 of an in situ aircraft verification experiment

    NASA Technical Reports Server (NTRS)

    Hasler, A. F.; Shenk, W.; Skillman, W.

    1976-01-01

    An initial experiment has been conducted to verify geostationary-satellite-derived cloud motion wind estimates with in situ aircraft wind velocity measurements. Case histories of 1/2 to 2 h were obtained for 3-10 km diameter cumulus cloud systems on 6 days. Also, one cirrus cloud case was obtained. In most cases the clouds were discrete enough that both the cloud motion and the ambient wind could be measured with the same aircraft Inertial Navigation System (INS). Since the INS drift error is the same for both the cloud motion and wind measurements, the drift error drops out of the relative motion determinations. The magnitude of the vector difference between the cloud motion and the ambient wind at the cloud base averaged 1.2 m/sec. The wind vector at higher levels in the cloud layer differed by about 3 to 5 m/sec from the cloud motion vector.

  6. Wind estimates from cloud motions: Phase 1 of an in situ aircraft verification experiment

    NASA Technical Reports Server (NTRS)

    Hasler, A. F.; Shenk, W. E.; Skillman, W.

    1974-01-01

    An initial experiment was conducted to verify geostationary satellite derived cloud motion wind estimates with in situ aircraft wind velocity measurements. Case histories of one-half hour to two hours were obtained for 3-10km diameter cumulus cloud systems on 6 days. Also, one cirrus cloud case was obtained. In most cases the clouds were discrete enough that both the cloud motion and the ambient wind could be measured with the same aircraft Inertial Navigation System (INS). Since the INS drift error is the same for both the cloud motion and wind measurements, the drift error subtracts out of the relative motion determinations. The magnitude of the vector difference between the cloud motion and the ambient wind at the cloud base averaged 1.2 m/sec. The wind vector at higher levels in the cloud layer differed by about 3 m/sec to 5 m/sec from the cloud motion vector.

  7. Evaluating ammonia (NH3) predictions in the NOAA National Air Quality Forecast Capability (NAQFC) using in situ aircraft, ground-level, and satellite measurements from the DISCOVER-AQ Colorado campaign

    NASA Astrophysics Data System (ADS)

    Battye, William H.; Bray, Casey D.; Aneja, Viney P.; Tong, Daniel; Lee, Pius; Tang, Youhua

    2016-09-01

    The U.S. National Oceanic and Atmospheric Administration (NOAA) is responsible for forecasting elevated levels of air pollution within the National Air Quality Forecast Capability (NAQFC). The current research uses measurements gathered in the DISCOVER-AQ Colorado field campaign and the concurrent Front Range Air Pollution and Photochemistry Experiment (FRAPPE) to test performance of the NAQFC CMAQ modeling framework for predicting NH3. The DISCOVER-AQ and FRAPPE field campaigns were carried out in July and August 2014 in Northeast Colorado. Model predictions are compared with measurements of NH3 gas concentrations and the NH4+ component of fine particulate matter concentrations measured directly by the aircraft in flight. We also compare CMAQ predictions with NH3 measurements from ground-based monitors within the DISCOVER-AQ Colorado geographic domain, and from the Tropospheric Emission Spectrometer (TES) on the Aura satellite. In situ aircraft measurements carried out in July and August of 2014 suggest that the NAQFC CMAQ model underestimated the NH3 concentration in Northeastern Colorado by a factor of ∼2.7 (NMB = -63%). Ground-level monitors also produced a similar result. Average satellite-retrieved NH3 levels also exceeded model predictions by a factor of 1.5-4.2 (NMB = -33 to -76%). The underestimation of NH3 was not accompanied by an underestimation of particulate NH4+, which is further controlled by factors including acid availability, removal rate, and gas-particle partition. The average measured concentration of NH4+ was close to the average predication (NMB = +18%). Seasonal patterns measured at an AMoN site in the region suggest that the underestimation of NH3 is not due to the seasonal allocation of emissions, but to the overall annual emissions estimate. The underestimation of NH3 varied across the study domain, with the largest differences occurring in a region of intensive agriculture near Greeley, Colorado, and in the vicinity of Denver. The

  8. Practical application of in situ aerosol measurement

    SciTech Connect

    O`Hern, T.J.; Rader, D.J.

    1993-09-01

    The use of in situ, real-time measurement techniques permits the characterization of airborne droplets and particles under conditions where traditional sampling methods can fail. For example, sampling method rely on the ability to sample and transport particles without biasing the properties of interest, and often are not applicable in harsh environment. Although in situ methods offer unique opportunities in these cases, these techniques introduce new concerns and must be used carefully if accurate measurement are to be made. Several in situ measurement techniques are reviewed here. As the field is rapidly evolving, the discussion is limited to those techniques which: (1) are commercially available, (2) provide real-time output, (3) measure the aerosol size distribution. Discussion is divided between single particle counters (which provide a flux-based or temporal measurement) and ensemble techniques (which provide a concentration-based or spatial measurement). Specific techniques discussed include phase Doppler, Mie scattering, and Fraunhofer diffraction, and commercial instruments based on these techniques.

  9. Autonomous in situ measurements of seawater alkalinity.

    PubMed

    Spaulding, Reggie S; DeGrandpre, Michael D; Beck, James C; Hart, Robert D; Peterson, Brittany; De Carlo, Eric H; Drupp, Patrick S; Hammar, Terry R

    2014-08-19

    Total alkalinity (AT) is an important parameter for describing the marine inorganic carbon system and understanding the effects of atmospheric CO2 on the oceans. Measurements of AT are limited, however, because of the laborious process of collecting and analyzing samples. In this work we evaluate the performance of an autonomous instrument for high temporal resolution measurements of seawater AT. The Submersible Autonomous Moored Instrument for alkalinity (SAMI-alk) uses a novel tracer monitored titration method where a colorimetric pH indicator quantifies both pH and relative volumes of sample and titrant, circumventing the need for gravimetric or volumetric measurements. The SAMI-alk performance was validated in the laboratory and in situ during two field studies. Overall in situ accuracy was -2.2 ± 13.1 μmol kg(-1) (n = 86), on the basis of comparison to discrete samples. Precision on duplicate analyses of a carbonate standard was ±4.7 μmol kg(-1) (n = 22). This prototype instrument can measure in situ AT hourly for one month, limited by consumption of reagent and standard solutions.

  10. 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.

  11. Chlorine Chemistry of the Lower Stratosphere: Aircraft (ALIAS, ER-2) and Balloon (BLISSs) In-Situ Measurements of HC1,NO(sub 2), andN(sub 2)O for Testing Heterogeneous Chemistry

    NASA Technical Reports Server (NTRS)

    Webster, C.; May, R.; Jaegle, L.; Hu, H.; Scott, D.; Stimpfle, R.; Salawitch, R.; Fahey, D.; Woodbridge, E.; Proffitt, M.; Margitan, J.

    1994-01-01

    Stratospheric concentrations of HC1 measured in the northern hemisphere from the ER-2 aircraft are significantly lower than model predictions using both gas phase and heterogeneous chemistry, but measurements in the southern hemisphere are in much better agreement.

  12. In situ PEM fuel cell water measurements

    SciTech Connect

    Borup, Rodney L; Mukundan, Rangachary; Davey, John R; Spendalow, Jacob S

    2008-01-01

    Efficient PEM fuel cell performance requires effective water management. The materials used, their durability, and the operating conditions under which fuel cells run, make efficient water management within a practical fuel cell system a primary challenge in developing commercially viable systems. We present experimental measurements of water content within operating fuel cells. in response to operational conditions, including transients and freezing conditions. To help understand the effect of components and operations, we examine water transport in operating fuel cells, measure the fuel cell water in situ and model the water transport within the fuel cell. High Frequency Resistance (HFR), AC Impedance and Neutron imaging (using NIST's facilities) were used to measure water content in operating fuel cells with various conditions, including current density, relative humidity, inlet flows, flow orientation and variable GDL properties. Ice formation in freezing cells was also monitored both during operation and shut-down conditions.

  13. Experimental Measurement of In Situ Stress

    NASA Astrophysics Data System (ADS)

    Tibbo, Maria; Milkereit, Bernd; Nasseri, Farzine; Schmitt, Douglas; Young, Paul

    2016-04-01

    The World Stress Map data is determined by stress indicators including earthquake focal mechanisms, in situ measurement in mining, oil and gas boreholes as well as the borehole cores, and geologic data. Unfortunately, these measurements are not only infrequent but sometimes infeasible, and do not provide nearly enough data points with high accuracy to correctly infer stress fields in deep mines around the world. Improvements in stress measurements of Earth's crust is fundamental to several industries such as oil and gas, mining, nuclear waste management, and enhanced geothermal systems. Quantifying the state of stress and the geophysical properties of different rock types is a major complication in geophysical monitoring of deep mines. Most stress measurement techniques involve either the boreholes or their cores, however these measurements usually only give stress along one axis, not the complete stress tensor. The goal of this project is to investigate a new method of acquiring a complete stress tensor of the in situ stress in the Earth's crust. This project is part of a comprehensive, exploration geophysical study in a deep, highly stressed mine located in Sudbury, Ontario, Canada, and focuses on two boreholes located in this mine. These boreholes are approximately 400 m long with NQ diameters and are located at depths of about 1300 - 1600 m and 1700 - 2000 m. Two borehole logging surveys were performed on both boreholes, October 2013 and July 2015, in order to perform a time-lapse analysis of the geophysical changes in the mine. These multi-parameter surveys include caliper, full waveform sonic, televiewer, chargeability (IP), and resistivity. Laboratory experiments have been performed on borehole core samples of varying geologies from each borehole. These experiments have measured the geophysical properties including elastic modulus, bulk modulus, P- and S-wave velocities, and density. The apparatus' used for this project are geophysical imaging cells capable

  14. In Situ Measurements of Meteoric Ions

    NASA Technical Reports Server (NTRS)

    Grebowsky, Joseph M.; Aiken, Arthur C.; Einaudi, Franco (Technical Monitor)

    2001-01-01

    Extraterrestrial material is the source of metal ions in the Earth's atmosphere, Each year approx. 10(exp 8) kg of material is intercepted by the Earth. The origin of this material is predominantly solar orbiting interplanetary debris from comets or asteroids that crosses the Earth's orbit. It contains a very small amount of interstellar material. On occasion the Earth passes through enhanced amounts of debris associated with the orbit of a decaying comet. This leads to enhanced meteor shower displays for up to several days. The number flux of shower material is typically several times the average sporadic background influx of material. Meteoric material is some of the earliest material formed in the solar system. By studying the relative elemental abundances of atmospheric metal ions, information can be gained on the chemical composition of cometary debris and the chemical makeup of the early solar system. Using in situ sampling with rocket-borne ion mass spectrometers; there have been approximately 50 flights that made measurements of the metal ion abundances at attitudes between 80 and 130 km. It is this altitude range where incoming meteoric particles am ablated, the larger ones giving rise to visible meteor. displays. In several rocket measurements isotopic ratios of different atomic ion mass components and metal molecular ion concentrations have been determined and used to identify unambiguously the measured species and to investigate the processes controlling the metal ion distributions The composition of the Earth's ionosphere was first sampled by an ion mass spectrometer flown an a rocket in 1956. In 1958 a rocket-borne ion spectrometer identified, fbr the first time, a layer of metal ions near 95 km. These data were interpreted as evidence of an extraterrestrial rather than a terrestrial source. Istomin predicted: "It seems probable that with some improvement in the method that analysis of the ion composition in the E-region may be used for determining

  15. Micro-sensors for in-situ meteorological measurements

    NASA Technical Reports Server (NTRS)

    Crisp, David; Kaiser, William J.; Vanzandt, Thomas R.; Tillman, James E.

    1993-01-01

    Improved in-situ meteorological measurements are needed for monitoring the weather and climate of the terrestrial and Martian atmospheres. We have initiated a program to assess the feasibility and utility of micro-sensors for precise in-situ meteorological measurements in these environments. Sensors are being developed for measuring pressure, temperature, wind velocity, humidity, and aerosol amounts. Silicon micro-machining and large scale integration technologies are being used to make sensors that are small, rugged, lightweight, and require very little power. Our long-term goal is to develop very accurate miniaturized sensors that can be incorporated into complete instrument packages or 'micro weather stations,' and deployed on a variety of platforms. If conventional commercially available silicon production techniques can be used to fabricate these sensor packages, it will eventually be possible to mass-produce them at low cost. For studies of the Earth's troposphere and stratosphere, they could be deployed on aircraft, dropsondes, radiosondes, or autonomous surface stations at remote sites. Improved sensor accuracy and reduced sensor cost are the primary challenges for these applications. For studies of the Martian atmosphere, these sensor packages could be incorporated into the small entry probes and surface landers that are being planned for the Mars Environmental SURvey (MESUR) Mission. That decade-long program will deploy a global network of small stations on the Martian surface for monitoring meteorological and geological processes. Low mass, low power, durability, large dynamic range and calibration stability are the principal challenges for this application. Our progress on each of these sensor types is presented.

  16. Laser in situ keratomileusis flap stability in an aviator following aircraft ejection.

    PubMed

    Richmond, Christopher J; Barker, Patrick D; Levine, Edgar M; Hofmeister, Elizabeth M

    2016-11-01

    We present the case of a 28-year-old male F/A-18F Super Hornet naval flight officer who ejected from an aircraft at 13 000 feet at a speed in excess of 350 knots 7 years after uneventful laser in situ keratomileusis (LASIK). The patient was evaluated the day after the ejection. No LASIK flap complications or epithelial defects were found, and the corrected distance visual acuity was 20/15 in both eyes.

  17. Evaluation of LIDAR/Polarimeter Aerosol Measurements by In Situ Instrumentation during DEVOTE

    NASA Astrophysics Data System (ADS)

    Beyersdorf, A. J.; Ziemba, L. D.; Anderson, B. E.; Dolgos, G.; Ottaviani, M.; Obland, M. D.; Rogers, R.; Thornhill, K. L.; Winstead, E. L.; Yang, M. M.; Hair, J. W.

    2011-12-01

    Combined measurements from LIDAR (LIght Detection And Ranging) and polarimeter instruments provide the opportunity for enhanced satellite observations of aerosol properties including retrievals of aerosol optical depth, single scattering albedo, effective radius, and refractive index. However, these retrievals (specifically for refractive index) have not been fully vetted and require additional intercomparisons with in situ measurements to improve accuracy. Proper validation of these combined LIDAR/polarimeter retrievals requires evaluation in varying atmospheric conditions and of varying aerosol composition. As part of this effort, two NASA Langley King Air aircraft have been outfitted to provide coordinated measurements of aerosol properties. One will be used as a remote sensing platform with the NASA Langley high-spectral resolution LIDAR (HSRL) and NASA GISS research scanning polarimeter (RSP). The second aircraft has been modified for use as an in situ platform and will house a suite of aerosol microphysical instrumentation, a pair of diode laser hygrometers (DLHs) for water vapor and cloud extinction measurements, and a polarized imaging nephelometer (PI-Neph). The remote sensing package has flown in a variety of campaigns, however only rarely has been able to coordinate with in situ measurements. The use of two collocated aircraft will allow for future coordinated flights to provide a more complete dataset for evaluation of aerosol retrievals and allow for fast-response capability. Results from the first coordinated King Air flights as part of DEVOTE (Development and Evaulation of satellite ValidatiOn Tools by Experimenters) will be presented. Flights are planned out of Hampton, VA during September and October 2011 including underflights of the CALIPSO satellite and overflights of ground-based AERONET (AErosol RObotic NETwork) sites. These will provide a comparison of aerosol properties between in situ and remote instruments (ground, aircraft, and satellite

  18. An Intercomparison of In Situ Observations of Cloud Water Content from the NSF Gulfstream V Aircraft During IDEAS 2013

    NASA Astrophysics Data System (ADS)

    Toohey, D. W.; Kalnajs, L.; Rainwater, B.; Twohy, C. H.; Noone, D. C.; Avallone, L. M.

    2014-12-01

    Cloud water contents (CWC) were measured in situ during the IDEAS 2013 campaign by direct absorption infrared laser instruments that employ two different sampling methods on the NCAR Gulfstream-V aircraft. The University of Colorado CLH-2 instrument, mounted under the wing in a canister, employs a fiber-coupled distributed feedback laser (DFL) and direct absorption to quantify total water concentrations within a closed path of known pressure and temperature downstream of a heated inlet. Similarly, the NCAR CVI instrument uses a MayCom compact tunable diode laser (TDL) hygrometer mounted inside the aircraft cabin to measure condensed water evaporated in a counterflow virtual impactor (CVI) inlet. These two CWC measurements, which have similar sub-isokinetic particle enhancement characteristics, should differ primarily by the amount of ambient water vapor that is admitted by the CLH-2 inlet, but rejected by the dry counterflow in the CVI. We measured that ambient water vapor with a Picarro cavity ringdown spectrometer sourced by a backward-facing inlet. During a series of flights through a variety of clouds near Broomfield, CO, we were able to intercompare these two methods for measuring CWCs, both of which are capable of high accuracy sampling over a wide range of CWCs from the lower atmosphere to the tropopause. The results help characterize the accuracy, time-response, and precision of the two methods, and they improve our understanding of the new approach for measuring CWC using the canister-mounted CLH-2 instrument on the Gulfstream-V aircraft.

  19. Evaluation of long-term surface-retrieved cloud droplet number concentration with in situ aircraft observations

    NASA Astrophysics Data System (ADS)

    Lim, Kyo-Sun Sunny; Riihimaki, Laura; Comstock, Jennifer M.; Schmid, Beat; Sivaraman, Chitra; Shi, Yan; McFarquhar, Greg M.

    2016-03-01

    A new operational retrieval of cloud droplet number concentration (ND) at cloud base has been produced from surface remote sensors at the Atmospheric Radiation Measurement (ARM) Southern Great Plains site for 13 years from January 1998 to January 2011. The retrieval is based on surface radiometer measurements of cloud optical depth from the multifilter rotating shadow band radiometer and liquid water path from the microwave radiometer (MWR). It is only applicable for single-layered overcast warm (stratus or stratocumulus) clouds. Evaluation with in situ aircraft measurements during the extended-term aircraft field campaign, Routine ARM Aerial Facility (AAF) Clouds with Low Optical Water Depths (CLOWD) Optical Radiative Observations (RACORO), shows that the retrieved ND robustly reproduces the primary mode of the in situ measured probability density function (PDF) but produces too wide a distribution, primarily caused by frequent high cloud droplet number concentration. Our analysis shows that the error in the MWR retrievals at low liquid water paths is one possible reason for this deficiency. Modification through the diagnosed liquid water path from the coordinate solution improves not only the PDF of the retrieved ND but also the relationship between the cloud droplet number concentration and cloud droplet effective radius. Consideration of entrainment effects rather than assuming an adiabatic cloud improves the values of the ND retrieval by reducing the magnitude of cloud droplet number concentration. Aircraft measurements and retrieval comparisons suggest that retrieving the vertical distribution of cloud droplet number concentration and effective radius is feasible with an improvement of the parameter representing the mixing effects between environment and clouds and with a better understanding of the effect of mixing degree on cloud properties.

  20. In situ measurement of conductivity during nanocomposite film deposition

    NASA Astrophysics Data System (ADS)

    Blattmann, Christoph O.; Pratsinis, Sotiris E.

    2016-05-01

    Flexible and electrically conductive nanocomposite films are essential for small, portable and even implantable electronic devices. Typically, such film synthesis and conductivity measurement are carried out sequentially. As a result, optimization of filler loading and size/morphology characteristics with respect to film conductivity is rather tedious and costly. Here, freshly-made Ag nanoparticles (nanosilver) are made by scalable flame aerosol technology and directly deposited onto polymeric (polystyrene and poly(methyl methacrylate)) films during which the resistance of the resulting nanocomposite is measured in situ. The formation and gas-phase growth of such flame-made nanosilver, just before incorporation onto the polymer film, is measured by thermophoretic sampling and microscopy. Monitoring the nanocomposite resistance in situ reveals the onset of conductive network formation by the deposited nanosilver growth and sinternecking. The in situ measurement is much faster and more accurate than conventional ex situ four-point resistance measurements since an electrically percolating network is detected upon its formation by the in situ technique. Nevertheless, general resistance trends with respect to filler loading and host polymer composition are consistent for both in situ and ex situ measurements. The time lag for the onset of a conductive network (i.e., percolation) depends linearly on the glass transition temperature (Tg) of the host polymer. This is attributed to the increased nanoparticle-polymer interaction with decreasing Tg. Proper selection of the host polymer in combination with in situ resistance monitoring therefore enable the optimal preparation of conductive nanocomposite films.

  1. Wind estimates from cloud motions - Results from Phases I, II and III of an in situ aircraft verification experiment

    NASA Technical Reports Server (NTRS)

    Hasler, A. F.; Shenk, W. E.; Skillman, W. C.

    1977-01-01

    An experiment is in progress to verify geostationary-satellite-derived cloud-motion wind estimates by in-situ aircraft wind-velocity measurements. One or more low-level aircraft equipped with Inertial Navigation Systems (INS) were used to define the vertical extent and horizontal motion of a cloud and to measure the ambient wind field. A high-level aircraft, also equipped with an INS, took photographs to describe the horizontal extent of the cloud field and to measure cloud motion. To date the experiment has been conducted over tropical oceans and in the western Gulf of Mexico. A total of 60 h have been spent tracking some 40 tropical cumulus and five cirrus clouds. Results for tropical cumulus clouds indicate excellent agreement between the cloud motion and the wind at cloud base. The magnitude of the vector difference between the cloud motion and the cloud-base wind is less than 1.3 m/s for 67% of the cases with track lengths of 1 h or longer. Similarly, the vector differences between the cloud motion and the wind at sub-cloud (150 m), mid-cloud, and cloud-top levels are 1.5, 3.6 and 7.0 m/s, respectively. The cirrus cloud motions agreed best with the mean wind in the cloud layer with a vector difference of about 1.6 m/s.

  2. Adaptation of an In Situ Ground-Based Tropospheric OH/HO2 Instrument for Aircraft Use

    NASA Technical Reports Server (NTRS)

    Brune, William H.

    1997-01-01

    In-situ HO(x) (OH and HO2) measurements are an essential part of understanding the photochemistry of aircraft exhaust in the atmosphere. HO(x) affects the partitioning of nitrogen species in the NO(y) family. Its reactions are important sources and sinks for tropospheric ozone, thus providing a link between the NO(x) in aircraft exhaust and tropospheric ozone. OH mixing ratios are enhanced in aircraft wakes due to the photolysis of the HONO that is made close to the engine. Measurements of HO(x) in aircraft wakes, along with NO(x) measurements, thus provides a constraint on chemical models of the engine combustion and exhaust. The development of the Airborne Tropospheric Hydrogen Oxides Sensor (ATHOS) is reported. We designed, developed, and successfully flew this instrument. It was part of the instrument complement on board the NASA DC-8 during SUCCESS, which took place in Kansas in April and May, 1996. ATHOS has a limit-of-detection for OH (S/N = 2) of 10(exp 5) OH molecules cm(exp -3) in less than 150 seconds. While this sensitivity is about 2-3 times less than the initial projections in the proposal, it is more than adequate for good measurements of OH and HO2 from the planetary boundary layer to the stratosphere. Our participation in SUCCESS was to be engineering test flights for ATHOS; however, the high-quality measurements we obtained are being used to study HO(x) photochemistry in contrails, clouds, and the clear air.

  3. IN SITU ELLIPSOMETRY FOR SHOCK COMPRESSION MEASUREMENTS

    SciTech Connect

    Bakshi, L.; Eliezer, S.; Appelbaum, G.; Nissim, N.; Perelmutter, L.; Mond, M.

    2009-12-28

    Knowledge about the optical properties of materials at high pressure and high temperature is needed for EOS research. Ellipsometry measures the change in the polarization of a probe beam reflected from a surface. From the change in polarization, the real and imaginary parts of the time dependent complex index of refraction can be extracted. From the measured optical properties, fundamental physical properties of the material, such as emissivity, phase transitions, and electrical conductivity can be extracted. A dynamic ellipsometry measurement system with nanosecond resolution was built in order to measure all four stocks parameters. Gas gun was used to accelerate the impact flyer. Our experiments concentrated on the optical properties of 1020 steel targets with impact pressure range of 40-250 kbar. Although there are intrinsic difficulties with dynamic ellipsometric measurements, distinct changes were observed for 1020 steel under shock compression larger than 130 kbar, the alpha->epsilon phase transition.

  4. Recent Advances in the Tempest UAS for In-Situ Measurements in Highly-Dynamic Environments

    NASA Astrophysics Data System (ADS)

    Argrow, B. M.; Frew, E.; Houston, A. L.; Weiss, C.

    2014-12-01

    The spring 2010 deployment of the Tempest UAS during the VORTEX2 field campaign verified that a small UAS, supported by a customized mobile communications, command, and control (C3) architecture, could simultaneously satisfy Federal Aviation Administration (FAA) airspace requirements, and make in-situ thermodynamic measurements in supercell thunderstorms. A multi-hole airdata probe was recently integrated into the Tempest UAS airframe and verification flights were made in spring 2013 to collect in-situ wind measurements behind gust fronts produced by supercell thunderstorms in northeast Colorado. Using instantaneous aircraft attitude estimates from the autopilot, the in-situ measurements were converted to inertial wind estimates, and estimates of uncertainty in the wind measurements was examined. To date, the limited deployments of the Tempest UAS have primarily focused on addressing the engineering and regulatory requirements to conduct supercell research, and the Tempest UAS team of engineers and meteorologists is preparing for deployments with the focus on collecting targeted data for meteorological exploration and hypothesis testing. We describe the recent expansion of the operations area and altitude ceiling of the Tempest UAS, engineering issues for accurate inertial wind estimates, new concepts of operation that include the simultaneous deployment of multiple aircraft with mobile ground stations, and a brief description of our current effort to develop a capability for the Tempest UAS to perform autonomous path planning to maximize energy harvesting from the local wind field for increased endurance.

  5. 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.

  6. Intercomparisons of Lidar Backscatter Measurements and In-situ Data from GLOBE

    NASA Technical Reports Server (NTRS)

    Chudamani, S.; Spinhirne, James D.

    1992-01-01

    The Global Backscatter Experiment (GLOBE) took place during Nov. 1989 and May - Jun. 1990 and involved flight surveys of the Pacific region by the NASA DC-8 aircraft. The experimental instruments were lidars operating at wavelengths ranging from the visible to the thermal infrared and various optical particle counters for in-situ measurements. The primary motivation for GLOBE was the development of spaceborne wind sensing lidar. This paper will concern a comparison of direct backscatter measurements and backscatter calculated from particle counter data. Of special interest is that the particle measurements provided data on composition, and thus refractive index variation may be included in the analysis.

  7. Aerosol Characteristics during the CLAMS Experiment: in situ and Remote Sensing Measurements

    NASA Astrophysics Data System (ADS)

    Martins, J.; Remer, L.; Castanho, A.; Kaufman, Y.; Artaxo, P.; Mattoo, S.; Levy, R.; Kleidman, R.; Hobbs, P. V.; Plana-Fattori, A.; Yamasoe, M.; Redemann, J.

    2002-05-01

    Remote sensing measurements of aerosol properties were performed with MODIS on the Terra satellite, and with the MAS (MODIS Airborne Simulator) on the ER-2 aircraft during the CLAMS experiment. Remote sensing measurements were validated and complemented by in situ observations. MODIS measurements were operationally obtained over the dark ocean and were explored experimentally over the sun glint. During the experiment, MODIS results indicated episodes of long range transport of large aerosol particles over the CLAMS region. These particles were also identified in the in situ aerosol measurements and by aeronet size distributions. In situ aerosol measurements were performed aboard the University of Washington's Convair-580 Research Aircraft, on the Cheasapeake Lighthouse (about 25km from the coast), and on Wallops Island. Spectral absorption measurements performed on Nuclepore filters showed relatively low absorption efficiencies (about 0.21+/-0.08m2/g at 0.55um and 0.052+/-0.023m2/g at 2.1um at the Wallops Island station) and a spectral dependence close to 1/lambda or stronger. The spectral absorption shows characteristics of small black carbon (BC) particles (spectral dependence around 1/lambda) and soil dust-like particles (stronger absorption in the blue). Electron Microscopy pictures show cluster aggregates typically composed by black carbon particles and medium to large dust-like particles. The elemental composition of the particles measured on the Nuclepore filters also indicated the presence of dust-like particles on certain days of the experiment. The average absorption efficiency found in the area was significantly lower (by about one order of magnitude) than the absorption efficiency of biomass burning particles or urban pollution from developing countries. The complementarities of remote sensing and in situ measurements in the interpretation of the aerosol over the region will be discussed and explored.

  8. In situ performance measurements of the mitre photovoltaic array

    NASA Technical Reports Server (NTRS)

    Cherdak, A. S.; Haas, G. M.

    1977-01-01

    A data acquisition system was developed to provide more accurate and consistent measurement of the degradation of solar arrays. A technique was developed for in-situ measurement of photovoltaic panels of sufficient quality to permit evaluation of electrical performance over extended periods of several years.

  9. Subsurface In Situ Elemental Composition Measurements with PING

    NASA Technical Reports Server (NTRS)

    Parsons, Ann; McClanahan, Timothy; Bodnarik, Julia; Evans, Larry; Nowicki, Suzanne; Schweitzer, Jeffrey; Starr, Richard

    2013-01-01

    This paper describes the Probing In situ with Neutron and Gamma rays (PING) instrument, that can measure the subsurface elemental composition in situ for any rocky body in the solar system without the need for digging into the surface. PING consists of a Pulsed Neutron Generator (PNG), a gamma ray spectrometer and neutron detectors. Subsurface elements are stimulated by high-energy neutrons to emit gamma rays at characteristic energies. This paper will show how the detection of these gamma rays results in a measurement of elemental composition. Examples of the basalt to granite ratios for aluminum and silicon abundance are provided.

  10. In situ, operando measurements of rechargeable batteries

    DOE PAGES

    Wang, Howard; Wang, Feng

    2016-08-01

    This article reviews recent in operando measurements (IOMs) for addressing challenges in advancing rechargeable battery (RB) technologies. As the demands on energy and power density of RBs for broader applications continue to grow, current RB technologies are pushed to their theoretical and engineering limits while new approaches are being extensively investigated. Also, IOMs have become more powerful and effective research tools in recent years; they will play an essential role in developing next generation RBs. This review is organized around outstanding issues in battery science and engineering. Finally, we emphasize the critical need for quantifying the distribution and transport ofmore » active ions in functioning batteries over wide temporal and spatial scales in real time.« less

  11. In situ, operando measurements of rechargeable batteries

    SciTech Connect

    Wang, Howard; Wang, Feng

    2016-08-01

    This article reviews recent in operando measurements (IOMs) for addressing challenges in advancing rechargeable battery (RB) technologies. As the demands on energy and power density of RBs for broader applications continue to grow, current RB technologies are pushed to their theoretical and engineering limits while new approaches are being extensively investigated. Also, IOMs have become more powerful and effective research tools in recent years; they will play an essential role in developing next generation RBs. This review is organized around outstanding issues in battery science and engineering. Finally, we emphasize the critical need for quantifying the distribution and transport of active ions in functioning batteries over wide temporal and spatial scales in real time.

  12. In situ spectrophotometric measurement of dissolved inorganic carbon in seawater

    USGS Publications Warehouse

    Liua, Xuewu; Byrne, Robert H.; Adornato, Lori; Yates, Kimberly K.; Kaltenbacher, Eric; Ding, Xiaoling; Yang, Bo

    2013-01-01

    Autonomous in situ sensors are needed to document the effects of today’s rapid ocean uptake of atmospheric carbon dioxide (e.g., ocean acidification). General environmental conditions (e.g., biofouling, turbidity) and carbon-specific conditions (e.g., wide diel variations) present significant challenges to acquiring long-term measurements of dissolved inorganic carbon (DIC) with satisfactory accuracy and resolution. SEAS-DIC is a new in situ instrument designed to provide calibrated, high-frequency, long-term measurements of DIC in marine and fresh waters. Sample water is first acidified to convert all DIC to carbon dioxide (CO2). The sample and a known reagent solution are then equilibrated across a gas-permeable membrane. Spectrophotometric measurement of reagent pH can thereby determine the sample DIC over a wide dynamic range, with inherent calibration provided by the pH indicator’s molecular characteristics. Field trials indicate that SEAS-DIC performs well in biofouling and turbid waters, with a DIC accuracy and precision of ∼2 μmol kg–1 and a measurement rate of approximately once per minute. The acidic reagent protects the sensor cell from biofouling, and the gas-permeable membrane excludes particulates from the optical path. This instrument, the first spectrophotometric system capable of automated in situ DIC measurements, positions DIC to become a key parameter for in situ CO2-system characterizations.

  13. In situ measurements of phytoplankton fluorescence using low cost electronics.

    PubMed

    Leeuw, Thomas; Boss, Emmanuel S; Wright, Dana L

    2013-06-19

    Chlorophyll a fluorometry has long been used as a method to study phytoplankton in the ocean. In situ fluorometry is used frequently in oceanography to provide depth-resolved estimates of phytoplankton biomass. However, the high price of commercially manufactured in situ fluorometers has made them unavailable to some individuals and institutions. Presented here is an investigation into building an in situ fluorometer using low cost electronics. The goal was to construct an easily reproducible in situ fluorometer from simple and widely available electronic components. The simplicity and modest cost of the sensor makes it valuable to students and professionals alike. Open source sharing of architecture and software will allow students to reconstruct and customize the sensor on a small budget. Research applications that require numerous in situ fluorometers or expendable fluorometers can also benefit from this study. The sensor costs US$150.00 and can be constructed with little to no previous experience. The sensor uses a blue LED to excite chlorophyll a and measures fluorescence using a silicon photodiode. The sensor is controlled by an Arduino microcontroller that also serves as a data logger.

  14. In situ Measurements of Phytoplankton Fluorescence Using Low Cost Electronics

    PubMed Central

    Leeuw, Thomas; Boss, Emmanuel S.; Wright, Dana L.

    2013-01-01

    Chlorophyll a fluorometry has long been used as a method to study phytoplankton in the ocean. In situ fluorometry is used frequently in oceanography to provide depth-resolved estimates of phytoplankton biomass. However, the high price of commercially manufactured in situ fluorometers has made them unavailable to some individuals and institutions. Presented here is an investigation into building an in situ fluorometer using low cost electronics. The goal was to construct an easily reproducible in situ fluorometer from simple and widely available electronic components. The simplicity and modest cost of the sensor makes it valuable to students and professionals alike. Open source sharing of architecture and software will allow students to reconstruct and customize the sensor on a small budget. Research applications that require numerous in situ fluorometers or expendable fluorometers can also benefit from this study. The sensor costs US$150.00 and can be constructed with little to no previous experience. The sensor uses a blue LED to excite chlorophyll a and measures fluorescence using a silicon photodiode. The sensor is controlled by an Arduino microcontroller that also serves as a data logger. PMID:23783738

  15. IN SITU Device for Real-Time Catalyst Deactivation Measurements

    SciTech Connect

    Fossil Energy Research

    2008-03-31

    SCR catalyst management has become an important operations and maintenance activity for coal-fired utility boilers in the United States. To facilitate this activity, a method to determine Catalyst Activity in situ is being developed. This report describes the methodology and presents the results of a two ozone season demonstration conducted at Alabama Power Company's Gorgas Unit 10 during the 2005 and 2006 ozone seasons. The results showed that the in situ measurements are in good agreement with the laboratory measurements and the technique has some advantages over the traditional laboratory method of determining Catalyst Activity and Reactor Potential. SCR Performance is determined by the overall Reactor Potential (the product of the Catalyst Activity and the available surface area per unit of flue gas). The in situ approach provides a direct measurement of Reactor Potential under actual operating conditions, whereas laboratory measurements of Catalyst Activity need to be coupled with estimates of catalyst pluggage and flue gas flowrate in order to assess Reactor Potential. The project also showed that the in situ activity results can easily be integrated into catalyst management software to aid in making informed catalyst decisions.

  16. In situ sensors for measurements in the global trosposphere

    NASA Technical Reports Server (NTRS)

    Saeger, M. L.; Eaton, W. C.; Wright, R. S.; White, J. H.; Tommerdahl, J. B.

    1981-01-01

    Current techniques available for the in situ measurement of ambient trace gas species, particulate composition, and particulate size distribution are reviewed. The operational specifications of the various techniques are described. Most of the techniques described are those that have been used in airborne applications or show promise of being adaptable to airborne applications. Some of the instruments described are specialty items that are not commercially-available. In situ measurement techniques for several meteorological parameters important in the study of the distribution and transport of ambient air pollutants are discussed. Some remote measurement techniques for meteorological parameters are also discussed. State-of-the-art measurement capabilities are compared with a list of capabilities and specifications desired by NASA for ambient measurements in the global troposphere.

  17. Retrievals of Cloud Droplet Size from the RSP Data: Validation Using in Situ Measurements

    NASA Technical Reports Server (NTRS)

    Alexandrov, Mikhail D.; Cairns, Brian; Sinclair, Kenneth; Wasilewski, Andrzej P.; Ziemba, Luke; Crosbie, Ewan; Hair, John; Hu, Yongxiang; Hostetler, Chris; Stamnes, Snorre

    2016-01-01

    We present comparisons of cloud droplet size distributions retrieved from the Research Scanning Polarimeter (RSP) data with correlative in situ measurements made during the North Atlantic Aerosols and Marine Ecosystems Study (NAAMES). This field experiment was based at St. Johns airport, Newfoundland, Canada with the latest deployment in May - June 2016. RSP was onboard the NASA C-130 aircraft together with an array of in situ and other remote sensing instrumentation. The RSP is an along-track scanner measuring polarized and total reflectances in9 spectral channels. Its unique high angular resolution allows for characterization of liquid water droplet size using the rainbow structure observed in the polarized reflectances in the scattering angle range between 135 and 165 degrees. A parametric fitting algorithm applied to the polarized reflectances provides retrievals of the droplet effective radius and variance assuming a prescribed size distribution shape (gamma distribution). In addition to this, we use a non-parametric method, Rainbow Fourier Transform (RFT), which allows us to retrieve the droplet size distribution (DSD) itself. The latter is important in the case of clouds with complex structure, which results in multi-modal DSDs. During NAAMES the aircraft performed a number of flight patterns specifically designed for comparison of remote sensing retrievals and in situ measurements. These patterns consisted of two flight segments above the same straight ground track. One of these segments was flown above clouds allowing for remote sensing measurements, while the other was at the cloud top where cloud droplets were sampled. We compare the DSDs retrieved from the RSP data with in situ measurements made by the Cloud Droplet Probe (CDP). The comparisons show generally good agreement with deviations explainable by the position of the aircraft within cloud and by presence of additional cloud layers in RSP view that do not contribute to the in situ DSDs. In the

  18. In situ growth rate measurement of selective LPCVD of tungsten

    SciTech Connect

    Holleman, J.; Hasper, A.; Middelhoek, J. )

    1991-04-01

    This paper reports on the reflectance measurement during the selective deposition of W on Si covered with an insulator rating proven to be a convenient method to monitor the W deposition. The reflectance change during deposition allows the in situ measurement of the deposition rate. The influence of surface roughening due to either the W growth or an etching pretreatment of the wafer is modeled, as well as the effect of selectivity loss and lateral overgrowth.

  19. In situ and remote measurements of ions escaping from Venus

    NASA Astrophysics Data System (ADS)

    Kollmann, P.; Brandt, P. C.

    2013-12-01

    Venus is thought to lose a large fraction of its atmosphere in the form ions, mainly via pickup. The relative loss rate of the exosphere as neutrals or ions is not known, nor is the flux of escaping ions well constrained. Knowledge of these processes will shed light on the role an intrinsic magnetic field has in atmospheric erosion. We use the complementary in-situ plasma and energetic neutral atom (ENA) measurements from the Venus Express (VEx) spacecraft in order to constrain the ion escape. VEx completed about 2500 orbits to date and reached altitudes as low as 200km. The ASPERA/IMA instrument measured directional proton and oxygen ion spectra in the 10eV to 40keV range. We bin the data accumulated over the mission in space and bulk flow direction, yielding a direct measure of the local ion escape flux. While such in-situ measurements provide data without ambiguity, they are limited by the orbital coverage. This is why we include remote ENA measurements from the ASPERA/NPD (100eV to 10keV) instrument to our study. ENAs are created when escaping ions charge exchange with the high atmosphere atoms or molecules. We have done an exhaustive analysis of the data, excluding time periods of instrument contamination. Most ENA emission originates from low altitudes above Venus' limb. These measurements will be compared with the in-situ data, which allows constraining the atmospheric density at high altitudes. Interestingly, there are also ENA emissions from other directions, which were not sampled in-situ. This allows us to put a lower limit to the escape from these regions.

  20. TEPC measurements in commercial aircraft.

    PubMed

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

    2004-01-01

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

  1. In situ measurement of tritium permeation through stainless steel

    SciTech Connect

    Walter G. Luscher; David J. Senor; Kevin K. Clayton; Glen R. Longhurst

    2013-06-01

    The TMIST-2 irradiation experiment was conducted in the Advanced Test Reactor at Idaho National Laboratory to evaluate tritium permeation through Type 316 stainless steel (316 SS). The interior of a 316 SS seamless tube specimen was exposed to a 4He carrier gas mixed with a specified quantity of tritium (T2) to yield partial pressures of 0.1, 5, and 50 Pa at 292 degrees C and 330 degrees C. In situ tritium permeation measurements were made by passing a He-Ne sweep gas over the outer surface of the specimen to carry the permeated tritium to a bubbler column for liquid scintillation counting. Results from in situ permeation measurements were compared with predictions based on an ex-reactor permeation correlation in the literature. In situ permeation data were also used to derive an in-reactor permeation correlation as a function of temperature and pressure over the ranges considered in this study. In addition, the triton recoil contribution to tritium permeation, which results from the transmutation of 3He to T, was also evaluated by introducing a 4He carrier gas mixed with 3He at a partial pressure of 1013 Pa at 330 degrees C. Less than 3% of the tritium resulting from 3He transmutation contributed to tritium permeation.

  2. Comparison between S. T. radar and in situ balloon measurements

    NASA Technical Reports Server (NTRS)

    Dalaudier, F.; Barat, J.; Bertin, F.; Brun, E.; Crochet, M.; Cuq, F.

    1986-01-01

    A campaign for simultaneous in situ and remote observation of both troposphere and stratosphere took place near Aire-sur-l'Adour (in southeastern France) on May 4, 1984. The aim of this campaign was a better understanding of the physics of radar echoes. The backscattered signal obtained with a stratosphere-troposphere radar both at the vertical and 15 deg. off vertical is compared with the velocity and temperature measurements made in the same region (about 10 km north of the radar site) by balloon-borne ionic anenometers and temperature sensors. In situ measurements clearly indicate that the temperature fluctuations are not always consistent with the standard turbulent theory. Nevertheless, the assumptions generally made (isotropy and turbulent field in k) and the classical formulation so derived for radar reflectivity are able to reproduce the shape of the radar return power profiles in oblique directions. Another significant result is the confirmation of the role played by the atmospheric stratification in the vertical echo power. It is important to develop these simultaneous in situ and remote experiments for a better description of the dynamical and thermal structure of the atmosphere and for a better understanding of the mechanisms governing clear-air radar reflectivity.

  3. Combining Remote Sensing with in situ Measurements for Riverine Characterization

    NASA Astrophysics Data System (ADS)

    Calantoni, J.; Palmsten, M. L.; Simeonov, J.; Dobson, D. W.; Zarske, K.; Puleo, J. A.; Holland, K. T.

    2014-12-01

    At the U.S. Naval Research Laboratory we are employing a wide variety of novel remote sensing techniques combined with traditional in situ sampling to characterize riverine hydrodynamics and morphodynamics. Surface currents were estimated from particle image velocimetry (PIV) using imagery from visible to infrared bands, from both fixed and airborne platforms. Terrestrial LIDAR has been used for subaerial mapping from a fixed platform. Additionally, LIDAR has been combined with hydrographic surveying (multibeam) in mobile scanning mode using a small boat. Hydrographic surveying (side scan) has also been performed using underwater autonomous vehicles. Surface drifters have been deployed in combination with a remotely operated, floating acoustic Doppler current profiler. Other fixed platform, in situ sensors, such as pencil beam and sector scanning sonars, acoustic Doppler velocimeters, and water level sensors have been deployed. We will present an overview of a variety of measurements from different rivers around the world focusing on validation examples of remotely sensed quantities with more traditional in situ measurements. Finally, we will discuss long-term goals to use remotely sensed data within an integrated environmental modeling framework.

  4. In situ correlative measurements for the ultraviolet differential absorption lidar and the high spectral resolution lidar air quality remote sensors: 1980 PEPE/NEROS program

    NASA Technical Reports Server (NTRS)

    Gregory, G. L.; Beck, S. M.; Mathis, J. J., Jr.

    1981-01-01

    In situ correlative measurements were obtained with a NASA aircraft in support of two NASA airborne remote sensors participating in the Environmental Protection Agency's 1980persistent elevated pollution episode (PEPE) and Northeast regional oxidant study (NEROS) field program in order to provide data for evaluating the capability of two remote sensors for measuring mixing layer height, and ozone and aerosol concentrations in the troposphere during the 1980 PEPE/NEROS program. The in situ aircraft was instrumented to measure temperature, dewpoint temperature, ozone concentrations, and light scattering coefficient. In situ measurements for ten correlative missions are given and discussed. Each data set is presented in graphical and tabular format aircraft flight plans are included.

  5. In Situ Measurement of Tritium Permeation Through Stainless Steel

    SciTech Connect

    Luscher, Walter G.; Senor, David J.; Clayton, Kevin; Longhurst, Glen

    2013-06-01

    The TMIST-2 irradiation experiment was conducted in the Advanced Test Reactor at Idaho National Laboratory to evaluate tritium permeation through Type 316 stainless steel (316 SS). The interior of a 316 SS seamless tube specimen was exposed to a 4He carrier gas mixed with a specified quantity of tritium (T2) to yield partial pressures of 0.1, 5, and 50 Pa at 292° and 330°C. In-situ tritium permeation measurements were made by passing a He-Ne sweep gas over the outer surface of the specimen to carry the permeated tritium to a bubbler column for liquid scintillation counting. An irradiation enhancement factor (IEF) was determined by comparing in-situ permeation data with a correlation for ex-reactor hydrogen permeation through austenitic stainless steel developed from literature data and reported by Le Claire. Nominal values for the IEF ranged between 3 and 5 for 316 SS. In-situ permeation data were also used to derive an in-reactor permeation correlation as a function of temperature and pressure. In addition, the triton recoil contribution to tritium permeation, which results from the transmutation of 3He to T, was also evaluated by introducing a 4He carrier gas mixed with 3He at a partial pressure of 1013 Pa at 330°C. Less than 3% of the tritium resulting from 3He transmutation contributed to tritium permeation.

  6. IN-SITU MEASUREMENT OF TRITIUM PERMEATION THROUGH STAINLESS STEEL

    SciTech Connect

    Luscher, Walter G.; Senor, David J.; Clayton, Kevin; Longhurst, Glen R.

    2013-06-01

    The TMIST-2 irradiation experiment was conducted in the Advanced Test Reactor at Idaho National Laboratory to evaluate tritium permeation through Type 316 stainless steel (316 SS). The interior of a 316 SS seamless tube specimen was exposed to a 4He carrier gas mixed with a specified quantity of tritium (T2) to yield partial pressures of 0.1, 5, and 50 Pa at 292° and 330°C. In-situ tritium permeation measurements were made by passing a He-Ne sweep gas over the outer surface of the specimen to carry the permeated tritium to a bubbler column for liquid scintillation counting. An irradiation enhancement factor (IEF) was determined by comparing in-situ permeation data with a correlation for ex-reactor hydrogen permeation through austenitic stainless steel developed from literature data and reported by Le Claire. Nominal values for the IEF ranged between 3 and 5 for 316 SS. In-situ permeation data were also used to derive an in-reactor permeation correlation as a function of temperature and pressure. In addition, the triton recoil contribution to tritium permeation, which results from the transmutation of 3He to T, was also evaluated by introducing a 4He carrier gas mixed with 3He at a partial pressure of 1013 Pa at 330°C. Less than 3% of the tritium resulting from 3He transmutation contributed to tritium permeation.

  7. In situ refractometry for concentration measurements in refrigeration systems

    SciTech Connect

    Newell, T.A.

    1997-12-31

    An in situ refractometer was developed that is capable of measuring both the concentrations of oil in refrigerants, and the concentrations of aqueous coolant brines. A description of the technique, and example data are presented for R-134a/PAG oil, aqueous ethylene glycol, and aqueous propylene glycol solutions. The R-134a/PAG oil sensor data show a measurement sensitivity of less than 0.1% oil in the refrigerant, although error between data sets shows an uncertainty of approximately {+-}0.8%. Ethylene glycol and propylene glycol data show high signal level variations due to the large variation of the index of refraction between water and the glycols.

  8. In-Situ Dust Measurements in Jupiter's Gossamer Rings

    NASA Astrophysics Data System (ADS)

    Krueger, H.; Gruen, E.; Hamilton, D. P.

    2003-04-01

    Jupiter's ring system -- the archetype of ethereal ring systems -- consists of at least three components: the main ring, the vertically extended halo and the gossamer ring(s). The small moonlets Thebe and Amalthea orbit Jupiter within the gossamer ring region and structure in the intensity obtained from imaging observations indicates that these moons are the dominant sources of the gossamer ring material. The current picture implies that particles ejected from a source moon evolve inward under the Poynting-Robertson drag. Beyond Thebe's orbit, a very faint outward extension of the gossamer ring has also been observed which is not yet explained. Typical grain radii derived from optical imaging are a few micrometers. In November 2002 the Galileo spacecraft traversed the gossamer ring for the first time and had a close flyby at Amalthea. With the in-situ dust detector on board, dust measurements were collected throughout the gossamer ring and close to Amalthea. Several hundred impacts of dust grains were recorded and the data sets (impact charges, rise times, impact directions, etc.) of about 70 impacts were transmitted to Earth. In-situ dust measurements provide information about the physical properties of the dust environment not accessible with imaging techniques. They directly provide dust spatial densities along the spacecraft trajectory as well as grain sizes and impact speeds. This allows to test and refine current models of ring particle dynamics (see D. P. Hamilton et al., this conference). In particular, the direct measurement of grain sizes and dust spatial density in different regions of the gossamer ring allow to better constrain the forces dominating the grains' dynamics. The Galileo measurements in Jupiter's gossamer ring pave the way towards the in-situ dust measurements with Cassini in Saturn's E ring beginning in 2004.

  9. Galileo in-situ dust measurements in Jupiter's Gossamer Rings

    NASA Astrophysics Data System (ADS)

    Krueger, H.; Grün, E.; Hamilton, D. P.

    2003-05-01

    Jupiter's ring system -- the archetype of ethereal ring systems -- consists of at least three components: the main ring, the vertically extended halo and the gossamer ring(s). The small moonlets Thebe and Amalthea orbit Jupiter within the gossamer ring region and structure in the intensity obtained from imaging observations indicates that these moons are the dominant sources of the gossamer ring material. The current picture implies that particles ejected from a source moon evolve inward under the Poynting-Robertson drag. Beyond Thebe's orbit, a very faint outward extension of the gossamer ring has also been observed which is not yet explained. Typical grain radii derived from optical imaging are a few micrometers. In November 2002 the Galileo spacecraft traversed the gossamer ring for the first time and had a close flyby at Amalthea. With the in-situ dust detector on board, dust measurements were collected throughout the gossamer ring and close to Amalthea. Several hundred impacts of dust grains were recorded and the data sets (impact charges, rise times, impact directions, etc.) of about 90 impacts were transmitted to Earth. In-situ dust measurements provide information about the physical properties of the dust environment not accessible with imaging techniques. They directly provide dust spatial densities along the spacecraft trajectory as well as grain sizes and impact speeds. This allows to test and refine current models of ring particle dynamics (see D. P. Hamilton et al., this conference). In particular, the direct measurement of grain sizes and dust spatial density in different regions of the gossamer ring allow to better constrain the forces dominating the grains' dynamics. The Galileo measurements in Jupiter's gossamer ring pave the way towards the in-situ dust measurements with Cassini in Saturn's E ring beginning in 2004.

  10. A proposed in situ debris measurement in GEO

    NASA Astrophysics Data System (ADS)

    Opiela, J.; Liou, J.; Stansbery, E.

    Unlike the low Earth o bit (LEO) region, the geosynchronous Earth orbit (GEO)r debris environment is not well characterized. Since there is no natural mechanism to remove debris from GEO, where atmospheric drag is negligible, the GEO debris population will continue to grow. A good environment definition is needed for GEO satellite designers and operators to have reliable debris impact risk assessments and protection for their satellites. The current, general debris mitigation and protection measures may be applied to GEO satellites, but characterizing the GEO debris environment (flux, size distribution, orbit distribution, sources) will also allow measures tailored specifically for that environment. Ground-based GEO optical measurements in general have been limited to objects greater than about 15 cm. It is highly unlikely that any ground-based telescope can detect GEO debris smaller than 1 cm. In situ measurements are required to characterize the particle environment below the threshold of remote sensors. Firsthand knowledge of the untrackable debris population is critical to GEO environment definition. Two specific issues need to be addressed for any effective in situ measurements in GEO: detector type and potential contamination from interplanetary and interstellar dust. In this paper, we will discuss why the polyvinylidene fluoride (PVDF) material makes an ideal GEO debris detector. We will also show that impacts from debris, interplanetary dust, and interstellar dust are very different in many ways (size, impact speed, flux, etc). Debris impacts can be easily distinguished from other impacts.

  11. Evaluating NO2 Variability of In-Situ and Remote Sensing Observations from Aircraft and Ground Sites During DISCOVER-AQ

    NASA Astrophysics Data System (ADS)

    Silverman, M. L.; Szykman, J.; Chen, G.; Crawford, J. H.; Janz, S. J.; Kowalewski, M. G.; Lamsal, L. N.; Long, R.; Beaver, M. R.

    2014-12-01

    Spatial variability of NO2 has largely been examined from satellite NO2 column measurements. Understanding this variability is important for emission controls, health impacts, and photochemistry. However, due the short lifetime of NO2, its variability is difficult to capture. Ground based monitors are extremely important to evaluate satellite column measurements and provide more detailed spatial information. Unfortunately, ground monitors are limited in number and geographically sparse. The DISCOVER-AQ campaign provides a unique dataset that allows for the assessment of spatial variability from aircraft in-situ measurements on the NASA P-3B, remote sensing measurements from the Airborne Compact Atmospheric Mapper (ACAM) on the NASA UC-12 and NASA B200, and ground site measurements over the same area. We use first order structure functions to provide an analysis of spatial gradients over a given distance seen by the P-3B in-situ instruments and ACAM. The spatial variability of these measurements are then compared to ground measurements across the flight domain. Column densities are also calculated from the DISCOVER-AQ vertical profiles to assess the variability of a column within the aircraft profile. Results show that spatial variability depends on the airmass being sampled, polluted versus background conditions.

  12. In situ impedance measurement of microwave atmospheric pressure plasma

    NASA Astrophysics Data System (ADS)

    Lee, S. T.; Nam, W. J.; Lee, J. K.; Yun, G. S.

    2017-04-01

    The impedance of atmospheric pressure argon plasma jets driven by microwave frequency is determined in situ by a novel ‘two frequency method’. In the conventional method of reflection coefficient ({{S}}11) measurement, the frequency of the driving microwave power is scanned, which inevitably affects the plasma characters and leads to uncertainty in the estimated plasma impedance. In our proposed method, the frequency-scanning signal additional to the driving power is used to measure {{S}}11 over a wide frequency range, which enables accurate determination of the plasma impedance based on an equivalent circuit model. The measured resistance and reactance of the plasma increase with the driving power in agreement with the transmission line theory. Based on this in situ measurement of the plasma impedance, the net power coupled to the plasma has been determined. The overall power efficiency remains approximately unchanged around 45% for different input power levels owing to the competing effects between the impedance mismatch and the volume change of the plasma.

  13. 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.

  14. 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.

  15. In situ measurements of the mesosphere and stratosphere

    NASA Technical Reports Server (NTRS)

    Crosky, C.

    1976-01-01

    The operation of a subsonic, Gerdien condenser probe for in situ measurements of the mesosphere and stratosphere is presented. The inclusion of a flashing Lyman alpha ultraviolet source provides an artifically produced ionization of particular constituents. Detailed theory of operation is presented and the data results from two flights are shown. A great deal of fine structure in mobility is observed due to the presence of various hydrated positive ions. The effect of the Lyman alpha source in the 35 km region was to dissociate a light hydrate ion rather than produce additional ionization. At the 70 km region, photodissociation of the heaviest ions (probably ice crystals) was also observed.

  16. In situ etch rate measurements of thin film combinatorial libraries

    SciTech Connect

    Perkins, J. D.; van Hest, M. F. A. M.; Teplin, C. W.; Dabney, M. S.; Ginley, D. S.

    2007-11-01

    We demonstrate the use of optical reflection mapping as an in situ characterization tool to evaluate the corrosion rate of compositionally graded thin film combinatorial libraries coated with a commercial glass etching paste. A multi-channel fiber-optically coupled CCD-array-based spectrometer was used to collect a series of reflectance maps from 300 to 1000 nm versus time. The thin film interference oscillations in the measured reflection spectra have been fitted to determine the film thickness as a function of time and thereby the etch rate. Application of this technique to an In–Mo–O composition spread library is presented as an example.

  17. In situ respiration measurements of megafauna in the Kermadec Trench

    NASA Astrophysics Data System (ADS)

    Nunnally, Clifton C.; Friedman, Jason R.; Drazen, Jeffrey C.

    2016-12-01

    The aim of this paper is to measure metabolic rates of megafauna living in depths greater than 6000 m. Echinoderms, actinarians and a polychaete were captured by remotely operated vehicle (ROV) and inserted into respiration chambers in situ at depths of 4049 m, 7140 m and 8074 m in the region of the Kermadec Trench SW Pacific Ocean. Hadal research has moved into a new frontier as technological improvements now allow for a meticulous investigation of trench ecology in depths greater than 6000 m. The development of an in situ respirometer for use in these studies was deployed in the Kermadec Trench to obtain the first ever rates of basal metabolic rates of hadal megafauna. Typical deep-sea experiments of individual animal physiology must deal with covarying factors of pressure, temperature, light and food supply in this study investigated the effects of pressure and increased food supply on overall animal metabolism. In the Kermadec Trench, holothurian respiration rates (n=4), 0.079±0.011 (mean±SE) μmol-O2 g-1 h-1, were higher than those captured at abyssal depths (n=2), 0.018±0.002 μmol-O2 g-1h-1, in the same region (p<0.001). When Q10 adjusted to a common temperature of 2.5 °C trench holothurian respiration rates ranged between 0.068 and 0.119 μmol-O2 g-1 h-1. Anemone respiration rates were remarkably similar between abyssal and hadal specimens, 0.110 and 0.111 μmol-O2 g-1 h-1, respectively. Our results on echinoderm respiration when corrected for temperature and mass fall below the slope regression when compared with other in situ measurements at shallower ocean depths.

  18. In situ measurements of Li isotopes in foraminifera

    NASA Astrophysics Data System (ADS)

    Vigier, Nathalie; Rollion-Bard, Claire; Spezzaferri, Silvia; Brunet, Fabrice

    2007-01-01

    In situ measurement of Li isotope ratios in foraminifera has been developed using a Cameca ims 1270 ion microprobe. In situ δ7Li analyses have been performed in biogenic calcite of planktonic foraminifera from various locations. Results show that for west Pacific mixed Globigerinoides and Globorotalia (22°S161°E), the isotopic variability between tests and within a single test, respectively, is not significantly greater than estimated analytical uncertainty (˜1.5‰). Mean δ7Li for several planktonic foraminifera tests corresponds to the seawater value, strongly suggesting negligible Li isotope fractionation relative to seawater, as previously inferred by Hall et al. (2005) using thermo-ionization mass spectrometer and multicollector-inductively coupled plasma-mass spectrometry techniques. Combined with scanning electron microscopy and ion microprobe imaging, micron-sized grains, enriched in lithium, silica and aluminum have been found in the foraminifera calcite matrix. A simple mixing model shows that 0.3-2 wt % of marine clays incorporated within the analyzed calcite would lower the foraminifera δ7Li value, by 3‰ to 10‰ relative to the isotopic composition of the pure calcite. By comparison, no such grains have been detected in corals. The presence of micron-sized silicate grains embedded within the foraminifera calcite is consistent with the Erez (2003) biomineralization model, involving calcite precipitation from seawater vacuoles. By contrast, coral calcium carbonate is instead precipitated from ions, which have been pumped or diffused through several membranes, impermeable to micrometric grains. Ion microprobe in situ δ7Li measurements in biogenic calcite present new methods for investigating both biomineralization processes and the past record of the ocean composition by exploring geochemical variations at a scale that is smaller in space and in time.

  19. In situ measurement requirements for a solar probe

    SciTech Connect

    Roberts, D.A.; Gosling, J.T.

    1996-09-01

    The authors present the rationale and in situ measurement requirements for a near-Sun mission intended to answer the central questions of the heating of the corona and the acceleration of the solar wind. These conclusions are based on panel discussions and presentations at the Marlboro workshop. They have in mind not a minimum mission, but rather one that is constrained but feasible within the current mass and telemetry rate restrictions. To distinguish between thermal, wave-driven, and microflare-driven models, the measurements must determine wave levels in a broad range of frequencies, resolve fine-scale structures, find the energetic particle content and its variations, and determine the bulk properties of a few species with detailed distributions for at least electrons and protons. They find that the in situ measurements needed to answer the main questions are similar to those proposed previously (magnetic field, plasma, high-energy particles, and plasma wave instruments) but without neutron and dust experiments. Telemetry and mass constraints will be significant but should not be prohibitive.

  20. In situ measurements of magnetic nanoparticles after placenta perfusion

    NASA Astrophysics Data System (ADS)

    Müller, Robert; Gläser, Marcus; Göhner, Claudia; Seyfarth, Lydia; Schleussner, Ekkehard; Hofmann, Andreas; Fritzsche, Wolfgang

    2015-04-01

    Nanoparticles (NP) present promising tools for medical applications. However, the investigation of their spatial and temporal distribution is hampered by missing in-situ particle detection and quantification technologies. The placenta perfusion experiment represents an interesting model for the study of the particle distribution at a biological barrier. It allows the ex-vivo investigation of the permeability of the placenta for materials of interest. We introduce an approach based on a magnetic system for an in situ measurement of the concentration of magnetic NPs in such an experiment. A previously off-line utilized magnetic readout device (sensitivity of ≈10-8 Am2) was used for long term measurements of magnetic NP of 100-150 nm size range in a closed circuit of a placenta perfusion. It represents a semiquantitative approach. The behavior of particles in the placenta and in the measurement system was studied, as well as the influence of particle surface modifications. The results suggest a transfer of a low amount of particles from the maternal to the fetal blood circuit.

  1. Quantifying Stratospheric Ozone in the Upper Troposphere Using in situ Measurements of HCl

    SciTech Connect

    Atherton, C S; Bergmann, D J; Marcy, T P; Fahey, D W; Gao, R S; Popp, P J; Richard, E C; Thompson, T L; Rosenlof, K H; Ray, E A; Salawitch, R J; Ridley, B A; . Weinheimer, A J; Loewenstein, M; Weinstock, E M; Mahoney, M J

    2004-03-08

    A chemical ionization mass spectrometry (CIMS) technique has been developed for precise in situ measurements of hydrochloric acid (HCl) from a high-altitude aircraft. In measurements at subtropical latitudes, minimum HCl values found in the upper troposphere (UT) are often near or below the 0.005-ppbv detection limit of the measurements, indicating that background HCl values are much lower than a global mean estimate. However, significant abundances of HCl were observed in many UT air parcels as a result of stratosphere-to-troposphere transport events. A method for diagnosing the amount of stratospheric ozone in these UT parcels was developed using the compact linear correlation of HCl with ozone found throughout the lower stratosphere (LS). Expanded use of this method will lead to improved quantification of cross-tropopause transport events and validation of global chemical transport models.

  2. Quantifying stratospheric ozone in the upper troposphere with in situ measurements of HCl.

    PubMed

    Marcy, T P; Fahey, D W; Gao, R S; Popp, P J; Richard, E C; Thompson, T L; Rosenlof, K H; Ray, E A; Salawitch, R J; Atherton, C S; Bergmann, D J; Ridley, B A; Weinheimer, A J; Loewenstein, M; Weinstock, E M; Mahoney, M J

    2004-04-09

    We have developed a chemical ionization mass spectrometry technique for precise in situ measurements of hydrochloric acid (HCl) from a high-altitude aircraft. In measurements at subtropical latitudes, minimum HCl values found in the upper troposphere (UT) were often near or below the detection limit of the measurements (0.005 parts per billion by volume), indicating that background HCl values are much lower than a global mean estimate. However, significant abundances of HCl were observed in many UT air parcels, as a result of stratosphere-to-troposphere transport events. We developed a method for diagnosing the amount of stratospheric ozone in these UT parcels using the compact linear correlation of HCl with ozone found throughout the lower stratosphere (LS). Expanded use of this method will lead to improved quantification of cross-tropopause transport events and validation of global chemical transport models.

  3. Statistical modeling of in situ hiss amplitudes using ground measurements

    NASA Astrophysics Data System (ADS)

    Golden, D. I.; Spasojevic, M.; Li, W.; Nishimura, Y.

    2012-05-01

    Plasmaspheric hiss is a naturally occurring extremely low frequency electromagnetic emission that is often observed within the Earth's plasmasphere. Plasmaspheric hiss plays a major role in the scattering and loss of electrons from the Earth's radiation belts, thereby contributing to the maintenance of the slot region between the inner and outer electron belt. Traditionally, in situ satellite observations have been the measurement modality of choice for studies of plasmaspheric hiss due to their ability to directly measure the hiss source region. However, satellite studies are relatively short-lived and very few satellite receivers remain operational for an entire 11-year solar cycle. Ground stations, in contrast, may collect multiple solar cycles' worth of data during their lifetime, yet they cannot directly measure the hiss source region. This study aims to determine the extent to which measurements of hiss at midlatitude ground stations may be used to predict the mean amplitude of in situ measurements of plasmaspheric hiss. We use coincident measurements between Palmer Station, Antarctica (L = 2.4, 50°S invariant latitude) and the THEMIS spacecraft from June 2008 through May 2010, during solar minimum. Using an autoregressive multiple regression model, we show that in the local time sector from 00 < MLT < 12, when the ionosphere above Palmer Station is in darkness and hiss is observed at Palmer, the amplitude of plasmaspheric hiss observed by the THEMIS spacecraft is 1.4 times higher than when hiss is not observed at Palmer. In the same local time sector when the ground station is in daylight and hiss is observed, the THEMIS observed amplitudes are not significantly different from those when hiss is not observed on the ground. A stronger relationship is found in the local time sector from 12 < MLT < 24 where, when Palmer is in daylight and hiss is observed, THEMIS plasmaspheric hiss amplitudes are 2 times higher compared to when hiss is not observed at Palmer

  4. In-Situ Load System for Calibrating and Validating Aerodynamic Properties of Scaled Aircraft in Ground-Based Aerospace Testing Applications

    NASA Technical Reports Server (NTRS)

    Commo, Sean A. (Inventor); Lynn, Keith C. (Inventor); Landman, Drew (Inventor); Acheson, Michael J. (Inventor)

    2016-01-01

    An In-Situ Load System for calibrating and validating aerodynamic properties of scaled aircraft in ground-based aerospace testing applications includes an assembly having upper and lower components that are pivotably interconnected. A test weight can be connected to the lower component to apply a known force to a force balance. The orientation of the force balance can be varied, and the measured forces from the force balance can be compared to applied loads at various orientations to thereby develop calibration factors.

  5. In situ Micrometeorological Measurements during RxCADRE

    NASA Astrophysics Data System (ADS)

    Clements, C. B.; Hiers, J. K.; Strenfel, S. J.

    2009-12-01

    The Prescribed Fire Combustion and Atmospheric Dynamics Research Experiment (RxCADRE) was a collaborative research project designed to fully instrument prescribed fires in the Southeastern United States. Data were collected on pre-burn fuel loads, post burn consumption, ambient weather, in situ atmospheric dynamics, plume dynamics, radiant heat release (both from in-situ and remote sensors), in-situ fire behavior, and select fire effects. The sampling was conducted at Eglin Air Force Base, Florida, and the Joseph W. Jones Ecological Research Center in Newton, Georgia, from February 29 to March 6, 2008. Data were collected on 5 prescribed burns, totaling 4458 acres. The largest aerial ignition totaled 2,290 acres and the smallest ground ignition totaled 104 acres. Quantifying fire-atmospheric interactions is critical for understanding wildland fire dynamics and enhancing modeling of smoke plumes. During Rx-CADRE, atmospheric soundings using radiosondes were made at each burn prior to ignition. In situ micrometeorological measurements were made within each burn unit using five portable, 10-m towers equipped with sonic and prop anemometers, fine-wire thermocouples, and a carbon dioxide probes. The towers were arranged within the burn units to capture the wind and temperature fields as the fire front and plume passed the towers. Due to the interaction of fire lines following ignition, several of the fire fronts that passed the towers were backing fires and thus less intense. Preliminary results indicate that the average vertical velocities associated with the fire front passage were on the order of 3-5 m s-1 and average plume temperatures were on the order of 30-50 °C above ambient. During two of the experimental burns, radiosondes were released into the fire plumes to determine the vertical structure of the plume temperature, humidity, and winds. A radiosonde released into the plume during the burn conducted on 3 March 2008 indicated a definite plume boundary in the

  6. In Situ Airborne Instrumentation: Addressing and Solving Measurement Problems in Ice Clouds

    SciTech Connect

    Baumgardner, Darrel; Kok, Greg; Avallone, L.; Bansemer, A.; Borrmann, S.; Brown, P.; Bundke, U.; Chuang, P. Y.; Cziczo, D.; Field, P.; Gallagher, M.; Gayet, J. -F.; Korolev, A.; Kraemer, M.; McFarquhar, G.; Mertes, S.; Moehler, O.; Lance, S.; Lawson, P.; Petters, M. D.; Pratt, K.; Roberts, G.; Rogers, D.; Stetzer, O.; Stith, J.; Strapp, W.; Twohy, C.; Wendisch, M.

    2012-02-01

    A meeting of 31 international experts on in situ measurements from aircraft was held to identify unresolved questions concerning ice formation and evolution in ice clouds, assess the current state of instrumentation that can address these problems, introduce emerging technology that may overcome current measurement issues and recommend future courses of action that can improve our understanding of ice cloud microphysical processes and their impact on the environment. The meeting proceedings and outcome has been described in detail in a manuscript submitted to the Bulletin of the American Meteorological Society (BAMS) on March 24, 2011. This paper is currently under review. The remainder of this summary, in the following pages, is the text of the BAMS article. A technical note that will be published by the National Center for Atmospheric Research is currently underway and is expected to be published before the end of the year.

  7. In Situ Airborne Instrumentation: Addressing and Solving Measurement Problems in Ice Clouds

    DOE PAGES

    Baumgardner, Darrel; Kok, Greg; Avallone, L.; ...

    2012-02-01

    A meeting of 31 international experts on in situ measurements from aircraft was held to identify unresolved questions concerning ice formation and evolution in ice clouds, assess the current state of instrumentation that can address these problems, introduce emerging technology that may overcome current measurement issues and recommend future courses of action that can improve our understanding of ice cloud microphysical processes and their impact on the environment. The meeting proceedings and outcome has been described in detail in a manuscript submitted to the Bulletin of the American Meteorological Society (BAMS) on March 24, 2011. This paper is currently undermore » review. The remainder of this summary, in the following pages, is the text of the BAMS article. A technical note that will be published by the National Center for Atmospheric Research is currently underway and is expected to be published before the end of the year.« less

  8. Epoxy and acrylate sterolithography resins: in-situ property measurements

    SciTech Connect

    Guess, T.R.; Chambers, R.S.; Hinnerichs, T.D.

    1996-01-01

    Stereolithography is a rapid prototyping method that is becoming an important product realization and concurrent engineering tool, with applications in advanced and agile manufacturing. During the build process, material behavior plays a significant role in the mechanics leading to internal stresses and, potentially, to distortion (curling) of parts. The goal of the ``Stereolithography Manufacturing Process Modeling and Optimization`` LDRD program was to develop engineering tools for improving overall part accuracy during the stereolithography build process. These tools include phenomenological material models of solidifying stereolithography photocurable resins and a 3D finite element architecture that incorporates time varying material behavior, laser path dependence, and structural linkage. This SAND report discusses the in situ measurement of shrinkage and force relaxation behavior of two photocurable resins, and the measurement of curl in simple cantilever beams. These studies directly supported the development of phenomenological material models for solidifying resins and provided experimental curl data to compare to model predictions.

  9. In situ laser reflectance measurement of diffuse surfaces.

    PubMed

    Chan, W S; Khan, S U

    1978-08-01

    Report is made on an in situ method of laser reflectance measurement of diffuse surfaces by using a GaAs laser and off-the-shelf optical components not involving radiation integration over a hemisphere as with most conventional reflectometers. The design features and limitations are described. Several diffuse surfaces were evaluated by this method, and the reflectance results obtained were in good agreement with those determined by the method of integrating sphere that used MgCO(3) surface as a standard. The main advantages of this method are: the elimination of the need of a surface standard; the avoidance of having the surfaces in close contact with the measuring equipment; the accuracy better than 10%; and the relatively straightforward alignment.

  10. Contact sponge water absorption test implemented for in situ measures

    NASA Astrophysics Data System (ADS)

    Gaggero, Laura; Scrivano, Simona

    2016-04-01

    The contact sponge method is a non-destructive in-situ methodology used to estimate a water uptake coefficient. The procedure, unlike other in-situ measurement was proven to be directly comparable to the water uptake laboratory measurements, and was registered as UNI 11432:2011. The UNI Normal procedure requires to use a sponge with known density, soaked in water, weighed, placed on the material for 1 minute (UNI 11432, 2011; Pardini & Tiano, 2004), then weighed again. Difficulties arise in operating on test samples or on materials with porosity varied for decay. While carrying on the test, fluctuations in the bearing of the environmental parameters were negligible, but not the pressure applied to the surface, that induced the release of different water amounts towards the material. For this reason we designed a metal piece of the same diameter of the plate carrying the sponge, to be screwed at the tip of a pocket penetrometer. With this instrument the sponge was kept in contact with the surface for 1 minute applying two different loads, at first pushed with 0.3 kg/cm2 in order to press the sponge, but not its holder, against the surface. Then, a load of 1.1 kg/ cm2 was applied, still avoiding deviating the load to the sponge holder. We applied both the current and our implemented method to determine the water absorption by contact sponge on 5 fresh rock types (4 limestones: Fine - and Coarse grained Pietra di Vicenza, Rosso Verona, Breccia Aurora, and the silicoclastic Macigno sandstone). The results show that 1) the current methodology imply manual skill and experience to produce a coherent set of data; the variable involved are in fact not only the imposed pressure but also the compression mechanics. 2) The control on the applied pressure allowed reproducible measurements. Moreover, 3) the use of a thicker sponge enabled to apply the method even on rougher surfaces, as the device holding the sponge is not in contact with the tested object. Finally, 4) the

  11. Galileo In-Situ Dust Measurements in Jupiter's Gossamer Rings

    NASA Astrophysics Data System (ADS)

    Krueger, H.; Hamilton, D. P.; Gruen, E.

    Jupiter's ring system consists of at least three components: the inner main ring, the vertically extended halo and the gossamer ring(s) further out. The small moons Thebe and Amalthea orbit Jupiter within the gossamer ring and are believed to be the sources of gossamer ring material. A very faint ring extension has also been observed beyond Thebe's orbit. On 5 November 2002 the Galileo spacecraft traversed Jupiter's gossamer ring system for the first time. High-resolution dust data were obtained with the dust detector on board down to 2.33 R_J , i.e. well inside Amalthea's orbit. A second ring passage occurred on 21 September 2003, a few hours before Galileo impacted Jupiter. This time, dust data were successfully received down to Amalthea's orbit at 2.5 R_J , however, with much reduced time-resolution. Several thousand dust impacts were counted during both ring passages, and the full data sets (impact charges, rise times, impact directions, etc.) of about 90 dust impacts were transmitted to Earth. In-situ dust measurements provide information about the physical properties of the dust environment not accessible with imaging techniques. They directly measure dust spatial densities along the spacecraft trajectory as well as grain sizes and impact speeds. Our as yet preliminary analysis %of the gossamer ring data implies particle sizes in the sub-micron and micron range. The size distribution -- increasing towards smaller particles -- is similar in the Thebe ring and the ring's outer extension, whereas in the Amalthea ring it is steeper. Dust number densities are about 104 - 106 km-3 . Our dust data allow for the first time to compare in-situ measurements with the results optical obtained from the inversion of optical images. It appears that small sub-micron grains dominate the number density whereas larger particles with at least a few micron radii contribute most to the optical depth. The dust density shows previously unrecognised fine-structure in the ring between

  12. 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.

  13. Can in situ measurements be used to estimate the age of shallow cumulus clouds?

    NASA Astrophysics Data System (ADS)

    Witte, M.; Chuang, P. Y.

    2010-12-01

    Cumulus clouds exhibit a life cycle that consists of: a) the growth phase (increasing size, most notably in the vertical direction); b) mature phase (growth no longer occurs; any precipitation that develops is strongest during this period); and c) dissipation phase (cloud dissipates because of precipitation and/or entrainment; no more dynamical support). Radar can track clouds over time and give some sense of the age of each cloud, but most aircraft measurements are without a temporal context. If it is possible, determining the cloud age (even if it is approximate, i.e. determining the phase in its life cycle) based solely on in situ measurements could provide important context information. The existence of such a measure would be a useful tool for interpreting past and future in situ cloud measurements. We use LES model simulations of trade wind cumulus cloud fields from one case during the Barbados Oceanographic and Meteorological Experiment (BOMEX) to test several potential cumulus cloud “clocks.” One key metric is the in-cloud buoyancy perturbation from the clear air mean as a function of time, as measured by virtual potential temperature. In general, the mean buoyancy of a cloud initially increases from zero with time, peaks, and decreases to become negatively buoyant during the latter third of its life cycle, with the amplitude of buoyancy dependent on cloud size. In some cases (more commonly for larger clouds), multiple pulses of buoyancy occur, which complicate any potential cumulus clock (as also reported by Heus et al., 2009). Since the buoyancy perturbation is not single-valued over the life of a given cloud, nor is the magnitude of the perturbation sufficient to differentiate between a mature small cloud or a growing larger cloud, other parameters must be used in addition to cloud buoyancy to construct a useful in situ cloud clock.

  14. Observing lake ice phenology across Alaska using in situ sensors, aircraft, and satellites

    NASA Astrophysics Data System (ADS)

    Arp, C. D.; Jones, B. M.; Grosse, G.; Bodony, K.; Sturdivant, E.; Frey, K. E.

    2013-12-01

    late spring are evaluated in relation to models based on 0°C ATID for Alaska lake districts and accumulated freezing degree days (AFDD) for the Koyukuk lake district where a longer period of lake ice phenology data is available from aircraft surveys. To place short term lake ice phenology into a longer term context, we used a combination of remote sensing (optical and radar satellites imagery), in situ sensors, and ice growth and decay models on one large lake of regional significance to Arctic Alaska, Teshekpuk Lake. Because of its large area (850 km2) and shallow depth (7 m maximum), Teshekpuk may have the longest annual ice-cover duration of any lake in Alaska and thus a sentinel for analysis of Arctic climate change. Our long-term analysis (1947 to present) of both ice-out and ice-on timing suggest a mean open-water duration of 63 days and moderate trend towards an increasing open-water season (0.5 days per year, r2=0.21) primarily driven by earlier ice-out timing. Our analysis also suggests that Teshekpuk Lake may have maintained at partial perennial ice cover in 1956 and 1969. Future work on this lake, as well the ice phenology of other lakes and lake districts in Arctic and Boreal regions, will seek to understand both the limnological and climatological consequences ice phenology in the context of climate change and variability.

  15. Comparisons of Arctic In-Situ Snow and Ice Data with Airborne Passive Microwave Measurements

    NASA Technical Reports Server (NTRS)

    Markus, T.; Cavalien, D. J.; Gasiewski, A.; Sturm, M.; Klein, M.; Maslanik, J.; Stroeve, J.; Heinrichs, J.; Holmgren, J.; Irisov, V.

    2004-01-01

    As part of the AMSR-E sea ice validation campaign in March 2003, aircraft flights over the Arctic sea ice were coordinated with ground measurements of snow and sea ice properties. The surface-based measurements were in the vicinity of Barrow, AK, and at a Navy ice camp located in the Beaufort Sea. The NASA P-3 aircraft was equipped with the NOAA ETL PSR microwave radiometer that has the same frequencies as the AMSR-E sensor. The goal was to validate the standard AMSR-E products ice temperature and snow depth on sea ice. Ground measurements are the only way to validate these parameters. The higher spatial resolution of the PSR instrument (between 30 and 500 m, depending on altitude) enables a better comparison between ground measurements and microwave data because of the expected smaller spatial variability. Maps of PSR data can then be used for further down-scaling to AMSR-E pixel areas. Initial results show a good qualitative agreement between the in-situ snow depths and the PSR data. Detailed studies are underway and latest results will be presented.

  16. Combining in situ and Remote Measurements with Models: Picking the Right Tools

    NASA Astrophysics Data System (ADS)

    Dickerson, R. R.; Hains, J. C.; Burrows, J. P.

    2004-05-01

    Visibility reduction, photochemical smog, and the global climate changes these pollutants engender involve complex interactions of emissions, atmospheric transformations, and transport. In situ measurements, numerical simulations, and remotely sensed data all have strengths and weaknesses, but picking the right combination of tools can avoid the limitations of any one method to advance the science and provide policy-relevant research on the causes and nature of air pollution. The Regional Atmospheric Measurement, Modeling, and Prediction Program (RAMMPP) seeks a balanced approach to air pollution studies in the Mid Atlantic. We employ surface and airborne measurements as input and tests for air quality models of the Baltimore/Washington area. Both ozone and summertime haze tend to form in blobs covering areas hundreds of km on a side and lasting several days. Point and aircraft measurements offer high accuracy, but cannot always characterize the spatial and temporal extent of these masses. To provide the big picture, we are exploring the use of satellite data including GOME and SCIAMACHY for SO2, TOMS for tropospheric O3, and MODIS for aerosol optical depth. Comparison with direct measurements can greatly improve retrievals of atmospheric composition. For example, GOME identified a persistent hot spot in SO2 over eastern North America where many large, coal-fired power plants are located. Aircraft measurements confirmed the presence of this hotspot, but indicated an average column content of 0.65 DU (m atm cm), while the satellite instrument, indicated only 0.14 DU. GOME uses, however, an initial guess for the altitudinal distribution of the SO2, and when the retrieval algorithm is corrected with the observed profile, the result is 0.42 DU. Further improving the retrieval with more representative background values yields a mean SO2 column content of 0.52 DU, within experimental uncertainty of the aircraft value. Ozone and aerosol retrievals can be similarly

  17. Evaluation of long-term surface-retrieved cloud droplet number concentration with in situ aircraft observations: ARM Cloud Droplet Number Concentration

    SciTech Connect

    Lim, Kyo-Sun Sunny; Riihimaki, Laura; Comstock, Jennifer M.; Schmid, Beat; Sivaraman, Chitra; Shi, Yan; McFarquhar, Greg M.

    2016-03-06

    A new cloud-droplet number concentration (NDROP) value added product (VAP) has been produced at the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) site for the 13 years from January 1998 to January 2011. The retrieval is based on surface radiometer measurements of cloud optical depth from the multi-filter rotating shadow-band radiometer (MFRSR) and liquid water path from the microwave radiometer (MWR). It is only applicable for single-layered warm clouds. Validation with in situ aircraft measurements during the extended-term aircraft field campaign, Routine ARM Aerial Facility (AAF) CLOWD Optical Radiative Observations (RACORO), shows that the NDROP VAP robustly reproduces the primary mode of the in situ measured probability density function (PDF), but produces a too wide distribution, primarily caused by frequent high cloud-droplet number concentration. Our analysis shows that the error in the MWR retrievals at low liquid water paths is one possible reason for this deficiency. Modification through the diagnosed liquid water path from the coordinate solution improves not only the PDF of the NDROP VAP but also the relationship between the cloud-droplet number concentration and cloud-droplet effective radius. Consideration of entrainment effects rather than assuming an adiabatic cloud improves the values of the NDROP retrieval by reducing the magnitude of cloud-droplet number concentration. Aircraft measurements and retrieval comparisons suggest that retrieving the vertical distribution of cloud-droplet number concentration and effective radius is feasible with an improvement of the parameter representing the mixing effects between environment and clouds and with a better understanding of the effect of mixing degree on cloud properties.

  18. In-situ measurements of velocity structure within turbidity currents

    USGS Publications Warehouse

    Xu, J. P.; Noble, M.A.; Rosenfeld, L.K.

    2004-01-01

    Turbidity currents are thought to be the main mechanism to move ???500,000 m3 of sediments annually from the head of the Monterey Submarine Canyon to the deep-sea fan. Indirect evidence has shown frequent occurrences of such turbidity currents in the canyon, but the dynamic properties of the turbidity currents such as maximum speed, duration, and dimensions are still unknown. Here we present the first-ever in-situ measurements of velocity profiles of four turbidity currents whose maximum along-canyon velocity reached 190 cm/s. Two turbidity currents coincided with storms that produced the highest swells and the biggest stream flows during the year-long deployment. Copyright 2004 by the American Geophysical Union.

  19. Regular, Fast and Accurate Airborne In-Situ Methane Measurements Around the Tropopause

    NASA Astrophysics Data System (ADS)

    Dyroff, Christoph; Rauthe-Schöch, Armin; Schuck, Tanja J.; Zahn, Andreas

    2013-04-01

    We present a laser spectrometer for automated monthly measurements of methane (CH4) mixing ratios aboard the CARIBIC passenger aircraft. The instrument is based on a commercial fast methane analyzer (FMA, Los Gatos Res.), which was modified for fully unattended employment. A laboratory characterization was performed and the results with emphasis on the precision, cross sensitivity to H2O, and accuracy are presented. An in-flight calibration strategy is described, that utilizes CH4 measurements obtained from flask samples taken during the same flights. By statistical comparison of the in-situ measurements with the flask samples we derive a total uncetrainty estimate of ~ 3.85 ppbv (1?) around the tropopause, and ~ 12.4 ppbv (1?) during aircraft ascent and descent. Data from the first two years of airborne operation are presented that span a large part of the northern hemispheric upper troposphere and lowermost stratosphere, with occasional crossings of the tropics on flights to southern Africa. With its high spatial resolution and high accuracy this data set is unprecedented in the highly important atmospheric layer of the tropopause.

  20. 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.

  1. Development of Techniques for the In Situ Observation of OH and HO2 for Studies of the Impact of High-Altitude Supersonic Aircraft on the Stratosphere

    NASA Technical Reports Server (NTRS)

    Anderson, James G.

    1994-01-01

    This three-year project supported the construction, calibration, and deployment of a new instrument to measure the OH and HO2 radicals on the NASA ER-2 aircraft. The instrument has met and exceeded all of its design goals. The instrumentation represents a true quantum leap in performance over that achieved in previous HO(x) instruments built in our group. Sensitivity for OH was enhanced by over two orders of magnitude as the weight fell from approximately 1500 to less than 200 Kg. Reliability has been very high: HO(x) data are available for all flights during the first operational mission, the Stratospheric Photochemistry, Aerosols, and Dynamics Expedition (SPADE). The results of that experiment have been reported in the scientific literature and at conferences. Additionally, measurements of H2O and O3 were made and have been reported in the scientific literature. The measurements demonstrate the important role that OH and HO2 play in determining the concentration of ozone in the lower stratosphere. During the SPADE campaign, the measurements demonstrate that the catalytic removal is dominated by processes involving the odd-hydrogen and halogen radical extremely important constraint for photochemical models that are being used to assess the potential deleterious effects of super-sonic aircraft effluent on the burden of stratospheric ozone. A list of the papers that came from this research are included, along with a copy of the paper, 'Aircraft-borne, laser-induced fluorescence instrument for the in situ detection of hydroxyl and hydroperoxyl radicals'.

  2. Evaporation Measured In Situ by Sensible Heat Balance

    NASA Astrophysics Data System (ADS)

    Heitman, Josh; Xiao, Xinhua; Sauer, Thomas; Ren, Tusheng; Horton, Robert

    2016-04-01

    Measurement of evaporation independent from evapotranspiration remains a major challenge for quantifying water fluxes in the soil-plant-atmosphere system. Methodology based on soil sensible heat balance (SHB) has been developed to measure in situ, sub-surface soil water evaporation with heat-pulse sensors. Soil sensible heat flux and change in heat storage are measured at multiple depths near the soil surface, and a simple energy balance calculation is applied to determine latent heat flux (i.e., evaporation) as a residual. For bare surface conditions, comparison of SHB to micrometerological (Bowen ratio) and micro-lysimeter approaches indicates strong correlation (r2 = 0.96) with near 1:1 relationship and root mean square error of 0.2 mm/d. Recent efforts to apply SHB methodology in row-crop (maize) and vineyard systems demonstrate the potential for quantifying evaporation separate from evapotranspiration. For the maize system, SHB evaporation estimates differed from micro-lysimeters by < 0.2 mm/d. The SHB approach is one of very few measurement approaches that may be applied to partition evaporation from evapotranspiration.

  3. In situ measurement of thermal diffusivity in marine sediments

    NASA Astrophysics Data System (ADS)

    Feseker, Tomas; Treude, Tina; Krastel, Sebastian

    2014-05-01

    The temperature of marine sediments depends on the interplay between heat flow from below and bottom water temperature above. The heat flow is controlled by the regional geological history and stable over long periods of time, whereas the bottom water temperature is subject to both seasonal and long-term climatic changes. The thermal inertia of the sediment determines how rapidly and to what depth temperature changes propagate from the bottom water into the seabed. The influence of seasonal changes is usually limited to shallow depths, while long-term trends may also affect deeper sediment layers. The thermal diffusivity of sediment is its ability to conduct thermal energy relative to its ability to store thermal energy. It is a measure of thermal inertia. While the thermal conductivity can be measured using regular heat flow probes, it is difficult to measure the diffusivity in situ. Hence, empirical relationships that link conductivity to diffusivity are widely used to characterize the thermal inertia of sediments. Here, we present a new method for measuring the thermal diffusivity of marine sediments in situ, which is based on monitoring the changes in sediment temperature profiles over short periods of time. We report on a successful measurement from 400 m water depth on the western Svalbard margin, where we deployed a temperature probe by submersible. The "T-Stick" consists of a lance with 8 temperature sensors distributed equally over a length of 0.6 m and a data logger, which is attached to the upper part of the lance. Temperature profiles were recorded at a sampling interval of 10 seconds for a period of 10 days. The observations show that variations in the temperature profile were driven by changes in bottom water temperature. Inverse modeling of the recorded temperature profiles allowed us to determine the thermal diffusivity of the sediment. The new method will help to better characterize the heat exchange across the sediment-water interface and

  4. 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.

  5. In Situ Measurements of Meteoric Ions. Chapter 8

    NASA Technical Reports Server (NTRS)

    Grebowsky, Joseph M.; Aikin, Arthur C.; Vondrak, Richard R. (Technical Monitor)

    2001-01-01

    Metal ions found in the atmosphere above 60 km are the result of incoming meteoroid atmospheric ablation. Layers of metal ions are detected by sounding rocket in situ mass spectrometric sampling in the 80 to 130 km region, which coincides with the altitude region where meteors are observed. Enhancements of metal ion concentrations occur during meteor showers. Even outside of shower periods, the metal ion altitude profiles vary from measurement to measurement. Double layers are frequent at middle latitudes. More than 40 different meteoric atomic and molecular ions, including isotopes, have been detected. Atmospheric metal ions on average have an abundance that matches chrondritic material, the same composition as the early solar system. However there are frequently local departures from this composition due to differential ablation, species dependent chemistry and mass dependent ion transport. Metal ions react with atmospheric O2, O, O3, H2O and H2O2 to form oxygenated and hydrogenated ionic compounds. Metal atomic ions at high altitudes have long lifetimes. As a result, these ions, in the presence of Earth's magnetic field, are transported over long distances by upper atmospheric winds and ionospheric electric fields. Satellite measurements have detected metal ions as high as, approximately 1000 km and have revealed circulation of the ions on a global scale.

  6. In-situ aircraft observations of ice concentrations within clouds over the Antarctic Peninsula and Larsen Ice Shelf

    NASA Astrophysics Data System (ADS)

    Grosvenor, D. P.; Choularton, T. W.; Lachlan-Cope, T.; Gallagher, M. W.; Crosier, J.; Bower, K. N.; Ladkin, R. S.; Dorsey, J. R.

    2012-07-01

    In-situ aircraft observations of ice crystal concentrations in Antarctic clouds are presented for the first time. Orographic, layer and wave clouds around the Antarctic Peninsula and Larsen Ice shelf regions were penetrated by the British Antarctic Survey's Twin Otter Aircraft, which was equipped with modern cloud physics probes. The clouds studied were mostly in the free troposphere and hence ice crystals blown from the surface are unlikely to have been a major source for the ice phase. The temperature range covered by the experiments was 0 to -21°C. The clouds were found to contain supercooled liquid water in most regions and at heterogeneous ice formation temperatures ice crystal concentrations (60 s averages) were often less than 0.07 l-1, although values up to 0.22 l-1 were observed. Estimates of observed aerosol concentrations were used as input into the DeMott et al., 2010 ice nuclei (IN) parameterisation. The observed ice crystal number concentrations were generally in broad agreement with the IN predictions, although on the whole the predicted values were higher. Possible reasons for this are discussed and include the lack of IN observations in this region with which to characterise the parameterisation, and/or problems in relating ice concentration measurements to IN concentrations. Other IN parameterisations significantly overestimated the number of ice particles. Generally ice particle concentrations were much lower than found in clouds in middle latitudes for a given temperature. Higher ice crystal concentrations were sometimes observed at temperatures warmer than -9 °C, with values of several per litre reached. These were attributable to secondary ice particle production by the Hallett Mossop process. Even in this temperature range it was observed that there were regions with little or no ice that were dominated by supercooled liquid water. It is likely that in some cases this was due to a lack of seeding ice crystals to act as rimers to initiate

  7. In-situ aircraft observations of ice concentrations within clouds over the Antarctic Peninsula and Larsen Ice Shelf

    NASA Astrophysics Data System (ADS)

    Grosvenor, D. P.; Choularton, T. W.; Lachlan-Cope, T.; Gallagher, M. W.; Crosier, J.; Bower, K. N.; Ladkin, R. S.; Dorsey, J. R.

    2012-12-01

    In-situ aircraft observations of ice crystal concentrations in Antarctic clouds are presented for the first time. Orographic, layer and wave clouds around the Antarctic Peninsula and Larsen Ice shelf regions were penetrated by the British Antarctic Survey's Twin Otter aircraft, which was equipped with modern cloud physics probes. The clouds studied were mostly in the free troposphere and hence ice crystals blown from the surface are unlikely to have been a major source for the ice phase. The temperature range covered by the experiments was 0 to -21 °C. The clouds were found to contain supercooled liquid water in most regions and at heterogeneous ice formation temperatures ice crystal concentrations (60 s averages) were often less than 0.07 l-1, although values up to 0.22 l-1 were observed. Estimates of observed aerosol concentrations were used as input into the DeMott et al. (2010) ice nuclei (IN) parameterisation. The observed ice crystal number concentrations were generally in broad agreement with the IN predictions, although on the whole the predicted values were higher. Possible reasons for this are discussed and include the lack of IN observations in this region with which to characterise the parameterisation, and/or problems in relating ice concentration measurements to IN concentrations. Other IN parameterisations significantly overestimated the number of ice particles. Generally ice particle concentrations were much lower than found in clouds in middle latitudes for a given temperature. Higher ice crystal concentrations were sometimes observed at temperatures warmer than -9 °C, with values of several per litre reached. These were attributable to secondary ice particle production by the Hallett Mossop process. Even in this temperature range it was observed that there were regions with little or no ice that were dominated by supercooled liquid water. It is likely that in some cases this was due to a lack of seeding ice crystals to act as rimers to initiate

  8. In Situ Observations and Sampling of Volcanic Emissions with Unmanned Aircraft: A NASA/UCR Case Study at Turrialba Volcano, Costa Rica

    NASA Technical Reports Server (NTRS)

    Pieri, David; Diaz, Jorge Andres; Bland, Geoffrey; Fladeland, Matthew; Madrigal, Yetty; Corrales, Ernesto; Alan, Alfredo; Alegria, Oscar; Realmuto, Vincent; Miles, Ted

    2011-01-01

    Burgeoning new technology in the design and development of robotic aircraft-unmanned aerial vehicles (UAVs)-presents unprecedented opportunities for the volcanology community to observe, measure, and sample eruption plumes and drifting volcanic clouds in situ. While manned aircraft can sample dilute parts of such emissions, demonstrated hazards to air breathing, and most particularly turbine, engines preclude penetration of the zones of highest ash concentrations. Such areas within plumes are often of highest interest with respect to boundary conditions of applicable mass-loading retrieval models, as well as Lagrangian, Eulerian, and hybrid transport models used by hazard responders to predict plume trajectories, particularly in the context of airborne hazards. Before the 2010 Ejyafyallajokull eruption in Iceland, ICAO zero-ash-tolerance rules were typically followed, particularly for relatively uncrowded Pacific Rim airspace, and over North and South America, where often diversion of aircraft around ash plumes and clouds was practical. The 2010 eruption in Iceland radically changed the paradigm, in that critical airspace over continental Europe and the United Kingdom were summarily shut by local civil aviation authorities and EURO CONTROL. A strong desire emerged for better real-time knowledge of ash cloud characteristics, particularly ash concentrations, and especially for validation of orbital multispectral imaging. UAV platforms appear to provide a viable adjunct, if not a primary source, of such in situ data for volcanic plumes and drifting volcanic clouds from explosive eruptions, with prompt and comprehensive application to aviation safety and to the basic science of volcanology. Current work is underway in Costa Rica at Turrialba volcano by the authors, with the goal of developing and testing new small, economical UAV platforms, with miniaturized instrument payloads, within a volcanic plume. We are underway with bi-monthly deployments of tethered SO2-sondes

  9. In situ measurement of inelastic light scattering in natural waters

    NASA Astrophysics Data System (ADS)

    Hu, Chuanmin

    Variation in the shape of solar absorption (Fraunhofer) lines are used to study the inelastic scattering in natural waters. In addition, oxygen absorption lines near 689nm are used to study the solar stimulated chlorophyll fluorescence. The prototype Oceanic Fraunhofer Line Discriminator (OFLD) has been further developed and improved by using a well protected fiber optic - wire conductor cable and underwater electronic housing. A Monte-Carlo code and a simple code have been modified to simulate the Raman scattering, DOM fluorescence and chlorophyll fluorescence. A series of in situ measurements have been conducted in clear ocean waters in the Florida Straits, in the turbid waters of Florida Bay, and in the vicinity of a coral reef in the Dry Tortugas. By comparing the reduced data with the model simulation results, the Raman scattering coefficient, b r with an excitation wavelength at 488nm, has been verified to be 2.6 × 10-4m-1 (Marshall and Smith, 1990), as opposed to 14.4 × 10- 4m-1 (Slusher and Derr, 1975). The wavelength dependence of b r cannot be accurately determined from the data set as the reported values (λ m-4 to λ m- 5) have an insignificant effect in the natural underwater light field. Generally, in clear water, the percentage of inelastic scattered light in the total light field at /lambda < 510nm is negligible for the whole water column, and this percentage increases with depth at /lambda > 510nm. At low concentrations (a y(/lambda = 380nm) less than 0.1m-1), DOM fluorescence plays a small role in the inelastic light field. However, chlorophyll fluorescence is much stronger than Raman scattering at 685nm. In shallow waters where a sea bottom affects the ambient light field, inelastic light is negligible for the whole visible band. Since Raman scattering is now well characterized, the new OFLD can be used to measure the solar stimulated in situ fluorescence. As a result, the fluorescence signals of various bottom surfaces, from coral to

  10. Hybrid-type temperature sensor for in situ measurement

    SciTech Connect

    Iuchi, Tohru; Hiraka, Kensuke

    2006-11-15

    A hybrid-type surface temperature sensor combines the contact and noncontact methods, which allows us to overcome the shortcomings of both methods. The hybrid-type surface thermometer is composed mainly of two components: a metal film sheet that makes contact with an object and a radiometer that is used to detect the radiance of the rear surface of the metal film, which is actually a modified radiation thermometer. Temperature measurement using the hybrid-type thermometer with a several tens micrometer thick Hastelloy sheet, a highly heat and corrosion resistant alloy, is possible with a systematic error of -0.5 K and random errors of {+-}0.5 K, in the temperature range from 900 to 1000 K. This thermometer provides a useful means for calibration of in situ temperature measurement in various processes, especially in the silicon semiconductor industry. This article introduces the basic idea of the hybrid-type surface sensor, presents experimental results and discussions, and finally describes some applications.

  11. Scattering error corrections for in situ absorption and attenuation measurements.

    PubMed

    McKee, David; Piskozub, Jacek; Brown, Ian

    2008-11-24

    Monte Carlo simulations are used to establish a weighting function that describes the collection of angular scattering for the WETLabs AC-9 reflecting tube absorption meter. The equivalent weighting function for the AC-9 attenuation sensor is found to be well approximated by a binary step function with photons scattered between zero and the collection half-width angle contributing to the scattering error and photons scattered at larger angles making zero contribution. A new scattering error correction procedure is developed that accounts for scattering collection artifacts in both absorption and attenuation measurements. The new correction method does not assume zero absorption in the near infrared (NIR), does not assume a wavelength independent scattering phase function, but does require simultaneous measurements of spectrally matched particulate backscattering. The new method is based on an iterative approach that assumes that the scattering phase function can be adequately modeled from estimates of particulate backscattering ratio and Fournier-Forand phase functions. It is applied to sets of in situ data representative of clear ocean water, moderately turbid coastal water and highly turbid coastal water. Initial results suggest significantly higher levels of attenuation and absorption than those obtained using previously published scattering error correction procedures. Scattering signals from each correction procedure have similar magnitudes but significant differences in spectral distribution are observed.

  12. Airborne In Situ and Ground-based Polarimetric Radar Measurements of Tropical Convection in Support of CRYSTAL-FACE

    NASA Technical Reports Server (NTRS)

    Poellot, Michael R.; Kucera, Paul A.

    2004-01-01

    This report describes the work performed by the University of North Dakota (UND) under NASA Grant NAG5-11509, titled Airborne In Situ and Ground-based Polarimetric Radar Measurements of Tropical Convection in Support of CRYSTAL-FACE. This work focused on the collection of data by two key platforms: the UND Citation II research aircraft and the NASA NPOL radar system. The CRYSTAL-FACE (C-F) mission addresses several key issues from the NASA Earth System Enterprise, including the variability of water in the atmosphere, the forcing provided by tropical cirrus and the response of the Earth system to this forcing. In situ measurements and radar observations of tropical convection, cirrus clouds and their environment are core elements of C-F. One of the primary issues that C-F is addressing is the relationship of tropical cirrus anvils to precipitating deep convection. The in situ measurements from C-F are being used to validate remote sensing of Earth-Atmosphere properties, increase our knowledge of upper tropospheric water vapor and its distribution, and increase our knowledge of tropical cirrus cloud morphology and composition. Radar measurements, especially polarimetric diversity observations available fiom the NASA NPOL radar, are providing essential information about the initiation, modulation, and dissipation of convective cores and the generation of associated anvils in tropical convection. Specifically, NPOL radar measurements contain information about convective intensity and its vertical structure for comparison with thermodynamic and kinematic environmental measurements observed from soundings. Because of the polarimetric diversity of MOL, statistics on bulk microphysical properties can be retrieved and compared to the other characteristics of convection and associated cirrus anvils. In summary, the central objectives of this proposal were to deploy the UND Citation research aircraft as an in situ sensing platform for this mission and to provide collaborative

  13. Carbon Dioxide and Methane Column Abundances Retrieved from Ground-Based Near-Infrared Solar Spectra and Comparison with In Situ Aircraft Profiles

    NASA Astrophysics Data System (ADS)

    Washenfelder, R. A.; Toon, G. C.; Blavier, J.; Wennberg, P. O.; Yang, Z.; Vay, S. A.; Sachse, G. W.; Blake, D. R.; Matross, D. M.; Gerbig, C.

    2004-12-01

    We have developed an automated observatory for measuring ground-based column abundances of CO2, CH4, CO, N2O, O2, H2O, and HF. Near-infrared spectra of the direct sun are measured between 3,900 - 15,600 cm-1 (0.67 - 2.56 μ m) by a Bruker 125HR Fourier Transform Spectrometer. This is the first laboratory in a proposed network of ground-based solar observatories that will be used for carbon cycle studies and validation of spaceborne column measurements of greenhouse gases. The laboratory was assembled in Pasadena, California and then permanently deployed to northern Wisconsin during May 2004. It is located in the heavily forested Chequamegon National Forest at the WLEF Tall Tower site, 14 km east of Park Falls, Wisconsin. This site was chosen because NOAA CMDL and other groups conduct intensive measurements in the area, including continuous monitoring of CO2 at six heights on the 447-m tall tower. CO2 and CH4 column abundances for May - November 2004 demonstrate ˜0.1% precision. The seasonal drawdown of CO2 is recognizable within the late-May column abundances. As part of the INTEX and COBRA campaigns, the DC-8 or King Air recorded in situ measurements during profiles over the WLEF site during five dates in July and August 2004. We will compare the column abundances of CO2, CH4, and CO with these in situ aircraft measurements.

  14. In situ flume measurements of resuspension in the North Sea

    NASA Astrophysics Data System (ADS)

    Thompson, C. E. L.; Couceiro, F.; Fones, G. R.; Helsby, R.; Amos, C. L.; Black, K.; Parker, E. R.; Greenwood, N.; Statham, P. J.; Kelly-Gerreyn, B. A.

    2011-07-01

    The in situ annular flume, Voyager II, was deployed at three sites in the North Sea in order to investigate resuspension events, to determine the physical characteristics of the seabed, to determine the threshold of resuspension of the bed and to quantify erosion rates and erosion depths. These are the first controlled, in situ flume experiments to study resuspension in the North Sea, and were combined with long-term measurements of waves and currents. Resuspension experiments were undertaken at two muddy, and one sandy site: north of the Dogger Bank (DG: water depths ˜80 m, very fine, poorly sorted, very fine-skewed sediment experiencing seasonal thermal stratification of the water column along with oxygen depletion); the Oyster Grounds (OG: ˜40 m, similar bed properties, year round water column thermal stratification, Atlantic forcing); and in the Sean Gas Field (SGF: ˜20 m, moderately sorted, very coarse-skewed sand, and well mixed water column). The erosion thresholds of the bed were found to be 0.66-1.04 Pa (DG) and 0.91-1.27 Pa (OG), with corresponding erosion depths of 0.1-0.15 mm and 0.02-0.06 mm throughout the experiments. Evaluation of a year of current velocities from 2007 indicated that at OG, resuspension of the consolidated bed was limited to on average ˜8% of the time as a result of tidal forcing alone for short (<30 min) durations, but would potentially increase during the winter as a result of wave influences. At DG, under similar conditions this would increase to 13%, and in the SGF, wave-induced resuspension events occurred throughout the year, with the potential exceedance of the threshold for suspension greater than 50% in January and March. Resuspension of bed material and erosion rates were closely related to applied bed shear stresses, and eroded depths were significantly correlated with the physical properties of the bed. Therefore, while complex variations in biogeophysical factors affected the critical threshold of erosion, once

  15. Comparisons of Remote Sensing Retrievals and in situ Measurements of Aerosol Fine Mode Fraction during ACE-Asia

    NASA Technical Reports Server (NTRS)

    Gasso, Santiago; O'Neill, Norm

    2006-01-01

    We present sunphotometer-retrieved and in situ fine mode fractions (FMF) measured onboard the same aircraft during the ACE-Asia experiment. Comparisons indicate that the latter can be used to identify whether the aerosol under observation is dominated by a mixture of modes or a single mode. Differences between retrieved and in situ FMF range from 5-20%. When profiles contained multiple layers of aerosols, the retrieved and measured FMF were segregated by layers. The comparison of layered and total FMF from the same profile indicates that columnar values are intermediate to those derived from layers. As a result, a remotely sensed FMF cannot be used to distinguish whether the aerosol under observation is composed of layers each with distinctive modal features or all layers with the same modal features. Thus, the use of FMF in multiple layer environments does not provide unique information on the aerosol under observation.

  16. Aerodynamic influences on atmospheric in situ measurements from sounding rockets

    NASA Astrophysics Data System (ADS)

    Gumbel, Jörg

    2001-06-01

    Sounding rockets are essential tools for studies of the mesosphere and lower thermosphere. However, in situ measurements from rockets are potentially subject to a number of perturbations related to the gas flow around the vehicle. This paper reviews the aerodynamic principles behind these perturbations. With respect to both data analysis and experiment design, there is a substantial need for improved understanding of aerodynamic effects. Any such analysis is complicated by the different flow regimes experienced during a rocket flight through the rarefied environment of the mesosphere and thermosphere. Numerical studies are presented using the Direct Simulation Monte Carlo (DSMC) approach, which is based on a tracing of individual molecules. Complementary experiments have been performed in a low-density wind tunnel. These experiments are crucial for the development of appropriate model parameterization. However, direct similarity between scaled wind tunnel results and arbitrary atmospheric flight conditions is usually difficult to achieve. Density, velocity, and temperature results are presented for different payload geometries and flow conditions. These illustrate a wide range of aerodynamic effects representative for rocket flights in the mesosphere and lower thermosphere.

  17. Measurements of in situ chemical ozone (oxidant) production rates

    NASA Astrophysics Data System (ADS)

    Huang, Hao; Faloon, Kate; Najera, Juan; Bloss, William

    2013-04-01

    Tropospheric ozone is a major air pollutant, harmful to human health, agricultural crops and vegetation, the main precursor to the atmospheric oxidants which initiate the degradation of most reactive gases emitted to the atmosphere, and an important greenhouse gas in its own right. The capacity to understand and predict tropospheric ozone levels is a key goal for atmospheric science - but one which is challenging, as ozone is formed in the atmosphere from the complex oxidation of VOCs in the presence of NOx and sunlight, on a timescale such that in situ chemical processes, deposition and transport all affect ozone levels. Known uncertainties in emissions, chemistry, dynamics and deposition affect the accuracy of predictions of current and future ozone levels, and hinder development of optimal air quality policies to mitigate against ozone exposure. Recently new approaches to directly measure the local chemical ozone production rate, bypassing the many uncertainties in emissions and chemical schemes, have been developed (Cazorla & Brune, AMT 2010). Here, we describe the development of an analogous Ozone Production Rate (OPR) approach: Air is sampled into parallel reactors, within which ozone formation either occurs as in the ambient atmosphere, or is suppressed. Comparisons of ozone levels exiting a pair of such reactors determines the net chemical oxidant production rate, after correction for perturbation of the NOx-O3 photochemical steady state, and when operated under conditions such that wall effects are minimised. We report preliminary measurements of local chemical ozone production made during the UK NERC ClearfLo (Clean Air for London) campaign at an urban background location in London in January and July 2012. The OPR system was used to measure the local chemical oxidant formation rate, which is compared with observed trends in O3 and NOx and the prevailing meteorology, and with the predictions of a detailed zero-dimensional atmospheric chemistry model

  18. 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.

  19. Microphysical and optical properties of precipitating drizzle and ice particles obtained from alternated lidar and in situ measurements

    NASA Astrophysics Data System (ADS)

    Gayet, J.-F.; Stachlewska, I. S.; Jourdan, O.; Shcherbakov, V.; Schwarzenboeck, A.; Neuber, R.

    2007-07-01

    During the international ASTAR experiment (Arctic Study of Aerosols, Clouds and Radiation) carried out from Longyearbyen (Spitsbergen) from 10 May to 11 June 2004, the AWI (Alfred Wegener Institute) Polar 2 aircraft was equipped with a unique combination of remote and in situ instruments. The airborne AMALi lidar provided downward backscatter and Depolarisation ratio profiles at 532 nm wavelength. The in situ instrumental setup comprised a Polar Nephelometer, a Cloud Particle Imager (CPI) as well as a Nevzorov and standard PMS probes to measure cloud particle properties in terms of scattering characteristics, particle morphology and size, and in-cloud partitioning of ice/water content. The objective of the paper is to present the results of a case study related to observations with ice crystals precipitating down to supercooled boundary-layer stratocumulus. The flight pattern was predefined in a way that firstly the AMALi lidar probed the cloud tops to guide the in situ measurements into a particular cloud formation. Three kinds of clouds with different microphysical and optical properties have therefore been quasi-simultaneously observed: (i) water droplets stratiform-layer, (ii) drizzle-drops fallstreak and (iii) precipitating ice-crystals from a cirrus cloud above. The signatures of these clouds are clearly evidenced from the in situ measurements and from the lidar profiles in term of backscatter and Depolarisation ratio. Accordingly, typical lidar ratios, i.e., extinction-to-backscatter ratios, are derived from the measured scattering phase function combined with subsequent particle shapes and size distributions. The backscatter profiles can therefore be retrieved under favourable conditions of low optical density. From these profiles extinction values in different cloud types can be obtained and compared with the direct in situ measurements.

  20. 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.

  1. In situ measurement of odor compound production by benthic cyanobacteria.

    PubMed

    Chen, Yan-Min; Hobson, Peter; Burch, Michael D; Lin, Tsair-Fuh

    2010-03-01

    A simple technique was developed to make in situ measurements of emission rates of two common odorants, 2-MIB and geosmin, and was validated with different natural communities of benthic cyanobacterial mats in Hope Valley Reservoir (HVR), South Australia, and Kin-Men Water Treatment Plant (TLR-WTP), Taiwan. A pair of parallel columns was used to differentiate between emission and loss rates caused by biodegradation, volatilization, and other mechanisms. Experimental results indicated that the loss rates followed a first-order relationship for all cases tested, with biodegradation and volatilization being the key mechanisms. The loss rates were comparable to those reported in the literature for biodegradation and those calculated from two-film theory for volatilization. After accounting for the loss rates, the net emission of geosmin and 2-MIB was estimated from experimental data. Odorant emission rates on the basis of column surface area, cyanobacterial cell number, and chlorophyll a (chl-a) were 4.2-4.4 ng h(-1) cm(-2), 1.0-5.5 x 10(-6) ng h(-1) cell(-1), and 3.2-3.5 ng h(-1)microg-chl(-1), respectively for 2-MIB released from benthic mats in TLR-WTP, and, 18-190 ng h(-1) cm(-2), 0.053-1.8 x 10(-3) ng h(-1) cell(-1), and 48-435 ng h(-1)microg-chl(-1) respectively for geosmin from benthic mats in HVR. The method developed provides a simple means to estimate the emission rates of odorants and possibly other algal metabolites from benthic cyanobacterial mats.

  2. Huygens Probe In-Situ Measurements : An Update

    NASA Astrophysics Data System (ADS)

    Lorenz, Ralph D.

    2015-04-01

    The global Titan perspective afforded by ongoing Cassini observations, and prospects for future in-situ exploration, have prompted a re-examination of Huygens data, yielding a number of recent new results. Gravity waves have been detected (Lorenz, Ferri and Young, Icarus, 2014) in the HASI descent temperature data, with ~2K amplitude. These waves are seen above about 60km, and analysis suggests they may therefore be controlled by interaction of upward-propagating waves with the zonal wind field. A curious cessation of detection of sound pulses by a Surface Science Package ultrasound instrument about 15 minutes after the probe landed appears to be best explained (Lorenz et al., Planetary and Space Science, 2014) by an accumulation of polyatomic vapors such as ethane, sweated out of the ground by the warm probe. Such gases have high acoustic attenuation, and were independently measured by the probe GCMS. The Huygens probe carried two radar altimeters. While their principal function was merely to trigger observation sequences at specific altitudes on the science instruments, the surface range history, and the Automatic Gain Control (AGC) housekeeping data, provide some useful information on Titan's surface (Lorenz et al., submitted). Small-scale topographic variations, and the surface radar reflectivity characteristics implied by the AGC variation with height, are discussed. A new integrated timeline product, which arranges second-by-second measurements from several Huygens sensors on a convenient, common tabulation, has been recently archived on the PDS Atmospheres node. Finally, a troubling discrepancy exists between radio occultation and infrared soundings from Cassini, and Huygens methane and temperature measurements in the lower stratosphere. The interdependence of these parameters will be discussed. In particular the possible role of the assumed probe mass history (depending on the unmeasured ablation from the heat shield) and the assumed zonal wind profile on

  3. In Situ Measurement of Energetic Electron Fluxes Inside Thunderclouds

    NASA Astrophysics Data System (ADS)

    Arabshahi, S.; Vodopiyanov, I. B.; Dwyer, J. R.; Rassoul, H.

    2013-12-01

    It is now well established that high-energy radiation is routinely produced by thunderclouds and lightning. This radiation is in the form of x-rays and gamma-rays with timescales ranging from sub-microsecond (x-rays associated with lightning leaders), to sub-millisecond (Terrestrial Gamma-ray Flashes), to minute long glows (Gamma-ray Glows from thunderclouds seen on the ground and in or near the cloud by aircrafts and balloons). It is generally accepted that these emissions originate from bremsstrahlung interactions of relativistic runaway electrons with air, which can be accelerated in the thundercloud/lightning electric fields and gain up to multi-MeV energies. However, the exact physical details of the mechanism that produces these runaway electrons are still unknown. In order to better understand the source of energetic radiation inside thunderclouds, we have begun a campaign of balloon-borne instruments to directly measure the flux of energetic electrons inside thunderclouds. In the current configuration, each balloon carries Geiger counters to record the energetic particles. Geiger counters are well suited for directly measuring energetic electrons and positrons and have the advantage of being lightweight and dependable. Due to the nature of the thunderstorm environment, the campaign has many design, communication, and safety challenges. In this presentation we will report on the status of the campaign and some of the physical insights gained from the data collected by our instruments. This work was supported in part by the NASA grant NNX12A002H and by DARPA grant HR0011-1-10-1-0061.

  4. An Evaluation of the Measurement Requirements for an In-Situ Wake Vortex Detection System

    NASA Technical Reports Server (NTRS)

    Fuhrmann, Henri D.; Stewart, Eric C.

    1996-01-01

    Results of a numerical simulation are presented to determine the feasibility of estimating the location and strength of a wake vortex from imperfect in-situ measurements. These estimates could be used to provide information to a pilot on how to avoid a hazardous wake vortex encounter. An iterative algorithm based on the method of secants was used to solve the four simultaneous equations describing the two-dimensional flow field around a pair of parallel counter-rotating vortices of equal and constant strength. The flow field information used by the algorithm could be derived from measurements from flow angle sensors mounted on the wing-tip of the detecting aircraft and an inertial navigation system. The study determined the propagated errors in the estimated location and strength of the vortex which resulted from random errors added to theoretically perfect measurements. The results are summarized in a series of charts and a table which make it possible to estimate these propagated errors for many practical situations. The situations include several generator-detector airplane combinations, different distances between the vortex and the detector airplane, as well as different levels of total measurement error.

  5. The international soil moisture network: A data hosting facility for global in situ soil moisture measurements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In situ measurements of soil moisture are invaluable for calibrating and validating land surface models and satellite-based soil moisture retrievals. In addition, long-term time series of in situ soil moisture measurements themselves can reveal trends in the water cycle related to climate or land co...

  6. Methods for Validation and Intercomparison of Remote Sensing and In situ Ice Water Measurements: Case Studies from CRYSTAL-FACE and Model Results

    NASA Technical Reports Server (NTRS)

    Sayres, D.S.; Pittman, J. V.; Smith, J. B.; Weinstock, E. M.; Anderson, J. G.; Heymsfield, G.; Li, L.; Fridlind, A.; Ackerman, A. S.

    2004-01-01

    Remote sensing observations, such as those from AURA, are necessary to understand the role of cirrus in determining the radiative and humidity budgets of the upper troposphere. Using these measurements quantitatively requires comparisons with in situ measurements that have previously been validated. However, a direct comparison of remote and in situ measurements is difficult due to the requirement that the spatial and temporal overlap be sufficient in order to guarantee that both instruments are measuring the same air parcel. A difficult as this might be for gas phase intercomparisons, cloud inhomogeneities significantly exacerbate the problem for cloud ice water content measurements. The CRYSTAL-FACE mission provided an opportunity to assess how well such intercomparisons can be performed and to establish flight plans that will be necessary for validation of future satellite instruments. During CRYSTAL-FACE, remote and in situ instruments were placed on different aircraft (NASA's ER-2 and WB-59, and the two planes flew in tandem so that the in situ payload flew in the field of view of the remote instruments. We show here that, even with this type of careful flight planning, it is not always possible to guarantee that remote and in situ instruments are viewing the same air parcel. We use ice water data derived from the in situ Harvard Total Water (HV-TW) instrument, and the remote Goddard Cloud Radar System (CRS) and show that agreement between HV-TW and CRS is a strong function of the horizontal separation and the time delay between the aircraft transects. We also use a cloud model to simulate possible trajectories through a cloud and evaluate the use of statistical analysis in determining the agreement between the two instruments. This type of analysis should guide flight planning for future intercomparison efforts, whether for aircraft or satellite-borne instrumentation.

  7. Novel Sensor for the In Situ Measurement of Uranium Fluxes

    SciTech Connect

    Hatfield, Kirk

    2015-02-10

    The goal of this project was to develop a sensor that incorporates the field-tested concepts of the passive flux meter to provide direct in situ measures of flux for uranium and groundwater in porous media. Measurable contaminant fluxes [J] are essentially the product of concentration [C] and groundwater flux or specific discharge [q ]. The sensor measures [J] and [q] by changes in contaminant and tracer amounts respectively on a sorbent. By using measurement rather than inference from static parameters, the sensor can directly advance conceptual and computational models for field scale simulations. The sensor was deployed in conjunction with DOE in obtaining field-scale quantification of subsurface processes affecting uranium transport (e.g., advection) and transformation (e.g., uranium attenuation) at the Rifle IFRC Site in Rifle, Colorado. Project results have expanded our current understanding of how field-scale spatial variations in fluxes of uranium, groundwater and salient electron donor/acceptors are coupled to spatial variations in measured microbial biomass/community composition, effective field-scale uranium mass balances, attenuation, and stability. The coupling between uranium, various nutrients and micro flora can be used to estimate field-scale rates of uranium attenuation and field-scale transitions in microbial communities. This research focuses on uranium (VI), but the sensor principles and design are applicable to field-scale fate and transport of other radionuclides. Laboratory studies focused on sorbent selection and calibration, along with sensor development and validation under controlled conditions. Field studies were conducted at the Rifle IFRC Site in Rifle, Colorado. These studies were closely coordinated with existing SBR (formerly ERSP) projects to complement data collection. Small field tests were conducted during the first two years that focused on evaluating field-scale deployment procedures and validating sensor performance under

  8. A domain analysis approach to clear-air turbulence forecasting using high-density in-situ measurements

    NASA Astrophysics Data System (ADS)

    Abernethy, Jennifer A.

    Pilots' ability to avoid clear-air turbulence (CAT) during flight affects the safety of the millions of people who fly commercial airlines and other aircraft, and turbulence costs millions in injuries and aircraft maintenance every year. Forecasting CAT is not straightforward, however; microscale features like the turbulence eddies that affect aircraft (100m) are below the current resolution of operational numerical weather prediction (NWP) models, and the only evidence of CAT episodes, until recently, has been sparse, subjective reports from pilots known as PIREPs. To forecast CAT, researchers use a simple weighted sum of top-performing turbulence indicators derived from NWP model outputs---termed diagnostics---based on their agreement with current PIREPs. However, a new, quantitative source of observation data---high-density measurements made by sensor equipment and software on aircraft, called in-situ measurements---is now available. The main goal of this thesis is to develop new data analysis and processing techniques to apply to the model and new observation data, in order to improve CAT forecasting accuracy. This thesis shows that using in-situ data improves forecasting accuracy and that automated machine learning algorithms such as support vector machines (SVM), logistic regression, and random forests, can match current performance while eliminating almost all hand-tuning. Feature subset selection is paired with the new algorithms to choose diagnostics that predict well as a group rather than individually. Specializing forecasts and choice of diagnostics by geographic region further improves accuracy because of the geographic variation in turbulence sources. This work uses random forests to find climatologically-relevant regions based on these variations and implements a forecasting system testbed which brings these techniques together to rapidly prototype new, regionalized versions of operational CAT forecasting systems.

  9. Airborne Sunphotometer, Airborne in-situ, Space-borne, and Ground-Based Measurements of Troposoheric Aerosol in Ace-2

    NASA Technical Reports Server (NTRS)

    Schmid, Beat; Collins, D.; Gasso, S.; Ostrom, E.; Powell, D.; Welton, E.; Durkee, P.; Livingstron, J.; Russell, P.; Flagan, R.; Hipskind, R. Stephen (Technical Monitor)

    2000-01-01

    We report on clear-sky column closure experiments performed in the Canary Islands during the second Aerosol Characterization Experiment (ACE-2) in June/July 1997. We present results obtained by combining airborne sunphotometer and in-situ aerosol measurements taken aboard the Pelican aircraft, space-borne NOAA/AVHRR data and ground-based lidars A wide range of aerosol types was encountered throughout the ACE-2 area, including background Atlantic marine, European pollution-derived, and African mineral dust. During !he two days discussed here, vertical profiles flown in cloud free air masses revealed three distinctly different layers: a marine boundary layer (MBL) with varying pollution levels, an elevated dust layer, and a very clean layer between the MBL and the dust layer. We found that the presence of the elevated dust layer removes the good agreement between satellite and sunphotometer AOD usually found in the absence of the dust layer. Using size-resolved composition information we have computed optical properties of the ambient aerosol from the in-situ measurements and subsequently compared those to the sunphotometer results. In the dust, the agreement in layer aerosol optical depth (380-1060 nm) is 3-8%. In the MBL there is tendency for the in-situ results to be slightly lower than the sunphotometer measurements (10-17% at 525 nm), but these differences are within the combined error bars of the measurements and computations.

  10. 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

    deployment. This stability is not affected by variation in pressure or temperature during flight. Biases and standard deviations of comparisons with flask samples suggest that atmospheric variability, flask-to-flask variability, and possible flask sampling biases may be driving biases in the comparison between flasks and in-situ CRDS measurements.

  11. Measurement of surface scratches on aircraft structures

    NASA Astrophysics Data System (ADS)

    Sarr, Dennis P.

    1996-01-01

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

  12. Kinematic analysis of in situ measurement during chemical mechanical planarization process

    SciTech Connect

    Li, Hongkai; Wang, Tongqing; Zhao, Qian; Meng, Yonggang; Lu, Xinchun

    2015-10-15

    Chemical mechanical planarization (CMP) is the most widely used planarization technique in semiconductor manufacturing presently. With the aid of in situ measurement technology, CMP tools can achieve good performance and stable productivity. However, the in situ measurement has remained unexplored from a kinematic standpoint. The available related resources for the kinematic analysis are very limited due to the complexity and technical secret. In this paper, a comprehensive kinematic analysis of in situ measurement is provided, including the analysis model, the measurement trajectory, and the measurement time of each zone of wafer surface during the practical CMP process. In addition, a lot of numerical calculations are performed to study the influences of main parameters on the measurement trajectory and the measurement velocity variation of the probe during the measurement process. All the efforts are expected to improve the in situ measurement system and promote the advancement in CMP control system.

  13. Kinematic analysis of in situ measurement during chemical mechanical planarization process

    NASA Astrophysics Data System (ADS)

    Li, Hongkai; Wang, Tongqing; Zhao, Qian; Meng, Yonggang; Lu, Xinchun

    2015-10-01

    Chemical mechanical planarization (CMP) is the most widely used planarization technique in semiconductor manufacturing presently. With the aid of in situ measurement technology, CMP tools can achieve good performance and stable productivity. However, the in situ measurement has remained unexplored from a kinematic standpoint. The available related resources for the kinematic analysis are very limited due to the complexity and technical secret. In this paper, a comprehensive kinematic analysis of in situ measurement is provided, including the analysis model, the measurement trajectory, and the measurement time of each zone of wafer surface during the practical CMP process. In addition, a lot of numerical calculations are performed to study the influences of main parameters on the measurement trajectory and the measurement velocity variation of the probe during the measurement process. All the efforts are expected to improve the in situ measurement system and promote the advancement in CMP control system.

  14. Cooperative Mobile Sensing Systems for In Situ Measurements in Hazardous Environments

    NASA Astrophysics Data System (ADS)

    Argrow, B.

    2005-12-01

    Sondes are typically deployed from manned aircraft or taken to altitude by a balloon before they are dropped. There are obvious safety and physical limitations that dictate where and how sondes are deployed. These limitations have severely constrained sonde deployment into highly dynamic and dangerous environments. Additionally, conventional parachute dropsondes provide no means for active control. The "smartsonde" idea is to integrate miniature sonde packages into micro air vehicles (MAVs). These MAVs will be ferried into the hard to reach and hazardous environments to provide in situ measurements in regions that have been heretofore out of reach. Once deployed, the MAV will provide some means of control of the sonde, to enable it to remain aloft and to provide some measure of directional control. Preliminary smartsonde communications experiments have been completed. These experiments focused on characterizing the capabilities of the 802.11.4 wireless protocol. Range measurements with 60-mW, 2.4-GHz radios showed 100% throughput rate over 2.7 km during air to ground tests. The experiments also demonstrated the integration of an in-house distributed computing system that provides the interface between the sensors, UAV flight computers, and the telemetry system. The University of Colorado's Research and Engineering Center for Unmanned Vehicles (RECUV) is developing an engineering system that integrates small mobile sensor attributes into flexible mobile sensor infrastructures to be deployed for in situ sensing in hazardous environments. There are three focus applications: 1) Wildfire, to address sensing, communications, situational awareness, and safety needs to support fire-fighting operations and to increase capabilities for dynamic data acquisition for modeling and prediction; 2) Polar, where heterogeneous mixes of platforms and sensors will provide in-situ data acquisition from beneath the ocean surface into the troposphere; 3) Storm, to address the challenges

  15. Atmospheric Balloon Swarms for Persistent In-Situ Measurements in Hurricanes

    NASA Astrophysics Data System (ADS)

    Meneghello, G.; Bewley, T.

    2015-12-01

    Real-time measurements within hurricanes are essential to improve forecasts, protect property and save lives. Current methods for obtaining in-situ data, including radar and satellite imagery as well as drop-sondes deployed from repeated aircraft flights above or even within the hurricane itself, are costly, dangerous and limited in duration or resolution. We demonstrate how a swarm of inexpensive, buoyancy-controlled, sensor-laden balloons can be deployed from altitude or from sea-level within a hurricane flow field, and coordinated autonomously in an energetically-efficient fashion to persistently and continuously monitor relevant properties (pressure, humidity, temperature, windspeed) of a hurricane for days at a time. Rather than fighting the gale-force winds in the storm, the strong, predictable stratification of these winds is leveraged to disperse the balloons into a favorable, time-evolving distribution and to follow the hurricane track as it moves. Certain target orbits of interest in the hurricane can be continuously sampled by some balloons, while other balloons make continuous sweeps between the eye and the spiral rain bands. We expect the acquired data to complement current measurement methods and to be instrumental in improving the numerical models' forecast skills.

  16. 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.

  17. Calibrated In Situ Measurement of UT/LS Water Vapor Using Chemical Ionization Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Thornberry, T. D.; Rollins, A.; Gao, R.; Watts, L. A.; Ciciora, S. J.; McLaughlin, R. J.; Fahey, D. W.

    2011-12-01

    Over the past several decades there has been considerable disagreement among in situ water vapor measurements by different instruments at the low part per million (ppm) mixing ratios found in the upper troposphere and lower stratosphere (UT/LS). These discrepancies contribute to uncertainty in our understanding of the microphysics related to cirrus cloud particle nucleation and growth and affect our ability to determine the effect of climate changes on the radiatively important feedback from UT/LS water vapor. To address the discrepancies observed in measured UT/LS water vapor, a new chemical ionization mass spectrometer (CIMS) instrument has been developed for the fast, precise, and accurate measurement of water vapor at low mixing ratios. The instrument utilizes a radioactive α particle source to ionize a flow of sample air drawn into the instrument. A cascade of ion-molecule reactions results in the production of protonated water ions proportional to the water vapor mixing ratio that are then detected by the mass spectrometer. The multi-step nature of the ionization mechanism results in a non-linear sensitivity to water vapor, necessitating calibration across the full range of values to be measured. To accomplish this calibration, we have developed a novel calibration scheme using catalytic oxidation of hydrogen to produce well-defined water vapor mixing ratios that can be introduced into the instrument inlet during flight. The CIMS instrument was deployed for the first time aboard the NASA WB-57 high altitude research aircraft during the Mid-latitude Airborne Cirrus Properties Experiment (MACPEX) mission in March and April 2011. The sensitivity of the instrument to water vapor was calibrated every ~45 minutes in flight from < 1 to 150 ppm. Analysis of in-flight data demonstrates a typical sensitivity of 2000 Hz/ppm at 4.5 ppm with a signal to noise ratio (2 σ) > 50 for a 1 second measurement. The instrument and its calibration system performed successfully in

  18. In-situ Balloon Measurements of Small Ice Particles in High-Latitude Cirrus

    NASA Astrophysics Data System (ADS)

    Kuhn, T.; Heymsfield, A.

    2015-12-01

    Thin cirrus clouds at high latitudes are often composed of small ice particles not larger than 100 μm. Cirrus clouds reflect incoming solar radiation, creating a cooling effect. At the same time these clouds absorb the infrared radiation from Earth, creating a greenhouse effect. The net effect, crucial for radiative transfer, depends on the cirrus microphysical properties, such as particle size distributions (PSD) and particle shapes. Knowledge of these cloud properties is also needed for calibrating/validating passive and active remote sensors. We report on a series of balloon-borne in-situ measurements that is carried out at a high-latitude location, Kiruna in northern Sweden (68N 21E). The measurements target upper tropospheric, cold cirrus clouds. The measurements are ongoing, and the method and first results are presented here. Ice particles in these clouds are predominantly very small, with a median size of measured particles of around 50 μm. Ice particles at these sizes are inherently difficult to measure with aircraft-mounted probes due to issues with resolution, sizing, and size-dependent sampling volume. These probes also suffer from problems with shattering of larger ice particles at the typically high aircraft speeds. The method used here avoids these issues. Furthermore, with a balloon-borne instrument data are collected as vertical profiles, more useful for calibrating or evaluating remote sensing measurements than data collected along horizontal traverses. Particles are collected on an oil-coated film at a sampling speed given directly by the ascending rate of the balloon, 4 m s-1. The collecting film is advanced uniformly inside the instrument so that an always un-used section of the film is exposed to ice particles, which are measured by imaging shortly after sampling. The high optical resolution of about 4 μm together with a pixel resolution of 1.65 μm allows particle detection at sizes of 10 μm and larger. For particles that are 20 μm (12

  19. First Results from the COFFEE Instrument: Airborne In-Situ Measurements of Formaldehyde over California

    NASA Astrophysics Data System (ADS)

    Iraci, L. T.; St Clair, J.; Marrero, J. E.; Gore, W.; Swanson, A. K.; Hanisco, T. F.

    2015-12-01

    The Compact Formaldehyde Fluorescence Experiment (COFFEE) instrument uses Non-Resonant Laser Induced Fluorescence (NR-LIF) to detect trace concentrations of formaldehyde as part of the Alpha Jet Atmospheric eXperiment (AJAX) payload. COFFEE, developed at NASA-GSFC, has a sensitivity of 100 pptv (1 sec) and can operate over a wide range of altitudes from the boundary layer to the lower stratosphere. It is mounted in an external wing pod on the Alpha Jet aircraft based at NASA-ARC, which can access altitudes from the surface up to 40,000 ft. We will present results from test flights performed in Fall 2015 over the Central Valley of California. Targets include an oil field, agricultural areas, and highways. Formaldehyde is one of the few urban pollutants that can be measured from space, and we will present plans to compare COFFEE in-situ data with space-based formaldehyde observations such as those from OMI (Aura) and OMPS (SuomiNPP).

  20. Diver-Operated Instruments for In-Situ Measurement of Optical Properties

    DTIC Science & Technology

    1999-09-30

    IMPACT/APPLICATION The new instruments are intended to advance the state of the art in diver-operated tools for underwater spectral measurements. They...Diver-Operated Instruments for In-Situ Measurement of Optical Properties Charles Mazel Physical Sciences Inc. 20 New England Business Center Andover...improved diver-operated instrumentation for making reflectance and fluorescence spectral measurements from benthic features in situ. The new instrument

  1. 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

    -flight calibrations, provided ground calibrations and testing were performed regularly. Comparisons between in situ CRDS measurements and flask measurements are consistent with expected measurement uncertainties for CH4 and CO, but differences are larger than expected for CO2. Biases and standard deviations of comparisons with flask samples suggest that atmospheric variability, flask-to-flask variability, and possible flask sampling biases may be driving the observed flask versus in situ CO2 differences rather than the CRDS measurements.

  2. In situ Gas Temperature Measurements by UV-Absorption Spectroscopy

    NASA Astrophysics Data System (ADS)

    Fateev, A.; Clausen, S.

    2009-02-01

    The absorption spectrum of the NO A2Σ+ ← X2Πγ-system can be used for in situ evaluation of gas temperature. Experiments were performed with a newly developed atmospheric-pressure high-temperature flow gas cell at highly uniform and stable gas temperatures over a 0.533 m path in the range from 23 °C to 1,500 °C. The gas temperature was evaluated (1) from the analysis of the structure of selected NO high-resolution γ-absorption bands and (2) from the analysis of vibrational distribution in the NO γ-absorption system in the (211-238) nm spectral range. The accuracy of both methods is discussed. Validation of the classical Lambert-Beer law has been demonstrated at NO concentrations up to 500 ppm and gas temperatures up to 1,500 °C over an optical absorption path length of 0.533 m.

  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. Aspects regarding vertical distribution of greenhouse gases resulted from in situ airborne measurements

    NASA Astrophysics Data System (ADS)

    Boscornea, Andreea; Sorin Vajaiac, Nicolae; Ardelean, Magdalena; Benciu, Silviu Stefan

    2016-04-01

    In the last decades the air quality, as well as other components of the environment, has been severely affected by uncontrolled emissions of gases - most known as greenhouse gases (GHG). The main role of GHG is given by the direct influence on the Earth's radiative budget, through Sun light scattering and indirectly by participating in cloud formation. Aldo, many efforts were made for reducing the high levels of these pollutants, e.g., International Panel on Climate Change (IPCC) initiatives, Montreal Protocol, etc., this issue is still open. In this context, this study aims to present several aspects regarding the vertical distribution in the lower atmosphere of some greenhouse gases: water vapours, CO, CO2 and methane. Bucharest and its metropolitan area is one of the most polluted regions of Romania due to high traffic. For assessing the air quality of this area, in situ measurements of water vapours, CO, CO2 and CH4 were performed using a Britten Norman Islander BN2 aircraft equipped with a Picarro gas analyser, model G2401-mc, able to provide precised, continuous and accurate data in real time. This configuration consisting in aircraft and airborne instruments was tested for the first time in Romania. For accomplishing the objectives of the measurement campaign, there were proposed several flight strategies which included vertical and horizontal soundings from 105 m to 3300 m and vice-versa around Clinceni area (20 km West of Bucharest). During 5 days (25.08.2015 - 31.08.2015) were performed 7 flights comprising 10h 18min research flight hours. The measured concentrations of GHS ranged between 0.18 - 2.2 ppm for water vapours with an average maximum value of 1.7 ppm, 0.04 - 0.53 ppm for CO with an average maximum value of 0.21 ppm, 377 - 437.5 ppm for CO2 with an average maximum value of 397 ppm and 1.7 - 6.1 ppm for CH4 with an average maximum value of 2.195 ppm. It was noticed that measured concentrations of GHG are decreasing for high values of sounding

  5. In situ monitoring of the integrity of bonded repair patches on aircraft and civil infrastructures

    NASA Astrophysics Data System (ADS)

    Kumar, Amrita; Roach, Dennis; Beard, Shawn; Qing, Xinlin; Hannum, Robert

    2006-03-01

    Monitoring the continued health of aircraft subsystems and identifying problems before they affect airworthiness has been a long-term goal of the aviation industry. Because in-service conditions and failure modes experienced by structures are generally complex and unknown, conservative calendar-based or usage-based scheduled maintenance practices are overly time-consuming, labor-intensive and expensive. Metal structures such as helicopters and other transportation systems are likely to develop fatigue cracks under cyclic loads and corrosive service environments. Early detection of cracks is a key element to prevent catastrophic failure and prolong structural life. Furthermore, as structures age, maintenance service frequency and costs increase while performance and availability decrease. Current non-destructive inspection (NDI) techniques that can potentially be used for this purpose typically involve complex, time-intensive procedures, which are labor-intensive and expensive. Most techniques require access to the damaged area on at least one side, and sometimes on both sides. This can be very difficult for monitoring of certain inaccessible regions. In those cases, inspection may require removal of access panels or even structural disassembly. Once access has been obtained, automated inspection techniques likely will not be practical due to the bulk of the required equipment. Results obtained from these techniques may also be sensitive to the sweep speed, tool orientation, and downward pressure. This can be especially problematic for hand-held inspection tools where none of these parameters is mechanically controlled. As a result, data can vary drastically from one inspection to the next, from one technician to the next, and even from one sweep to the next. Structural health monitoring (SHM) offers the promise of a paradigm shift from schedule-driven maintenance to condition-based maintenance (CBM) of assets. Sensors embedded permanently in aircraft safety

  6. The Coupling of ClONO2, ClO, and NO2 in the Lower Stratosphere From in Situ Observations Using the NASA ER-2 Aircraft

    NASA Technical Reports Server (NTRS)

    Stimpfle, R. E.; Cohen, R. C.; Bonne, G. P.; Voss, P. B.; Perkins, K. K.; Koch, L. C.; Anderson, J. G.; Salawitch, R. J.; Gao, R. S.

    1999-01-01

    The first in situ measurements of ClONO2 in the lower stratosphere, acquired using the NASA ER-2 aircraft during the Polar Ozone Loss in the Arctic Region in Summer (POLARIS) mission, are combined with simultaneous measurements of ClO, NO2, temperature, pressure, and the calculated photolysis rate coefficient (J(sub ClONO2)) to examine the balance between production and loss of ClONO2. The observations demonstrate the ClONO2 photochemical steady state measurement, [ClONO2](sup PSS) = k[ClO][No2]/J(sub ClONO2), is in good agreement with the direct measurement, [ClONO2](sup MEAS). For the bulk of the data (80%), where T > 220 K and latitudes > 45 N, [ClONO2](sup PPS) = 1.15 +/- 0.36(1-sigma)[ClONO2](sup MEAS), while for T< 220 K and latitudes < 45 N, the result is somewhat less at 1.01 +/- 0.30. The cause of the temperature and/or latitude trend is unidentified. These results are independent of solar zenith angle and air density, thus there is no evidence in support of a pressure-dependent quantum yield for photodissociation of ClONO2 at wavelengths > 300 nm. These measurements confirm the mechanism by which active nitrogen (NOx = NO + NO2) controls the abundance of active chlorine (Clx = ClO + Cl) in the stratosphere.

  7. Airborne In-Situ Measurements of Formaldehyde over California: First Results from the COFFEE Instrument

    NASA Astrophysics Data System (ADS)

    Marrero, Josette; St. Clair, Jason; Yates, Emma; Swanson, Andrew; Gore, Warren; Iraci, Laura; Hanisco, Thomas

    2016-04-01

    Formaldehyde (HCHO) is one of the most abundant oxygenated volatile organic compounds (VOCs) in the atmosphere, playing a role multiple atmospheric processes. Measurements of HCHO can be used to help quantify convective transport, the abundance of VOCs, and ozone production in urban environments. The Compact Formaldehyde FluorescencE Experiment (COFFEE) instrument uses Non-Resonant Laser Induced Fluorescence (NR-LIF) to detect trace concentrations of HCHO as part of the Alpha Jet Atmospheric eXperiment (AJAX) payload. Developed at NASA GSFC, COFFEE is a small, low maintenance instrument with a sensitivity of 100 pptv and a quick response time (1 sec). The COFFEE instrument has been customized to fit in an external wing pod on the Alpha Jet aircraft based at NASA ARC. The instrument can operate over a broad range of altitudes, from boundary layer to lower stratosphere, making it well suited for the Alpha Jet, which can access altitudes from the surface up to 40,000 ft. We will present results from flights performed over the Central Valley of California, including boundary layer measurements and vertical profiles in the tropospheric column. This region is of particular interest, due to its elevated levels of HCHO, revealed in satellite images, as well as its high ozone concentrations. In addition to HCHO, the AJAX payload includes measurements of atmospheric ozone, methane, and carbon dioxide. These results will be presented in conjunction with formaldehyde. Targets in the Central Valley consist of an oil field, agricultural areas, and highways, each of which can emit HCHO primarily and generate HCHO through secondary production. Formaldehyde is one of the few urban pollutants that can be measured from space. Plans to compare in-situ COFFEE data with satellite-based HCHO observations such as those from OMI (Aura) and OMPS (SuomiNPP) will also be presented.

  8. 15 years of upper tropospheric relative humidity in-situ measurements by the MOZAIC programme

    NASA Astrophysics Data System (ADS)

    Neis, Patrick; Smit, Herman G. J.; Alteköster, Lukas; Rohs, Susanne; Wahner, Andreas; Spichtinger, Peter; Petzold, Andreas

    2015-04-01

    Water vapour is a major parameter in weather prediction and climate research. However, the interaction between water vapour in the upper troposphere and lowermost stratosphere (UT/LS) and tropopause dynamics are not well understood. Furthermore, the knowledge about potential trends and feedback mechanisms of upper troposphere/lower stratosphere water vapour is low because of the large variability of observations and relatively short data records. A continuous measurement of upper tropospheric humidity (UTH) is still difficult because the abundance of UTH is highly variable on spatial and temporal scales, which cannot be resolved, neither by the global radiosondes network nor by satellites. Since 1994, UTH data with high spatial and temporal resolution are provided by the in-situ measurements aboard civil passenger aircraft from the MOZAIC/IAGOS-programme (www.iagos.org). The measurement system is based on a capacitive hygrometer with a simultaneous temperature measurement installed in a conventional Rosemount housing. In recent studies the MOZAIC Capacitive Hygrometer (MCH) and its improved successor IAGOS Capacitive Hygrometer (ICH) are compared against research-grade water vapour instruments during airborne field studies. The qualification of the Capacitive Hygrometer for the use in long-term observation programmes is successfully demonstrated and the continuation of high data quality is confirmed for the transition from MCH to ICH. After the reanalysis of the relative humidity data from 1994 to 2009, this extensive and unique data set is examined by criteria of continuity, homogeneity and quantity of data coverage, to identify global regions suitable for UTH climatology and trend analyses. For the identified target regions time series and climatologies of, e.g., relative humidity with respect to ice, temperature, and absolute humidity are investigated. First results of this study will be presented.

  9. 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.

  10. Validation of Large-Scale Geophysical Estimates Using In Situ Measurements with Representativeness Error

    NASA Astrophysics Data System (ADS)

    Konings, A. G.; Gruber, A.; Mccoll, K. A.; Alemohammad, S. H.; Entekhabi, D.

    2015-12-01

    Validating large-scale estimates of geophysical variables by comparing them to in situ measurements neglects the fact that these in situ measurements are not generally representative of the larger area. That is, in situ measurements contain some `representativeness error'. They also have their own sensor errors. The naïve approach of characterizing the errors of a remote sensing or modeling dataset by comparison to in situ measurements thus leads to error estimates that are spuriously inflated by the representativeness and other errors in the in situ measurements. Nevertheless, this naïve approach is still very common in the literature. In this work, we introduce an alternative estimator of the large-scale dataset error that explicitly takes into account the fact that the in situ measurements have some unknown error. The performance of the two estimators is then compared in the context of soil moisture datasets under different conditions for the true soil moisture climatology and dataset biases. The new estimator is shown to lead to a more accurate characterization of the dataset errors under the most common conditions. If a third dataset is available, the principles of the triple collocation method can be used to determine the errors of both the large-scale estimates and in situ measurements. However, triple collocation requires that the errors in all datasets are uncorrelated with each other and with the truth. We show that even when the assumptions of triple collocation are violated, a triple collocation-based validation approach may still be more accurate than a naïve comparison to in situ measurements that neglects representativeness errors.

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

    NASA Astrophysics Data System (ADS)

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

    2013-04-01

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

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

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

  13. Downwelling Solar Irradiance as a Critical Parameter for In-Situ Measurements in the MERMAID Database

    NASA Astrophysics Data System (ADS)

    Barker, Kathryn; Huot, Jean-Paul; Moore, Gerald; Mazeran, Constant; Lerebourg, Christophe; Zagolski, Francis

    2010-12-01

    The MERIS MAtchup In-situ Database (MERMAID) provides an essential tool for MERIS calibration and validation activities of ESA's Medium Resolution Imaging Spectrometer (MERIS). MERMAID comprises in-situ ρw from several measurement approaches, from fixed buoys and towers to floating instrumentation rigs. Analysis of the provided measurement protocols and the matchup data (in-situ and MERIS) has identified that sensor tilt seriously affects measurements of surface irradiance, and has consequent impacts on the accuracy of water reflectance, ρw, and matchup results. Activities intrinsic to the third MERIS reprocessing, such as the development of the vicarious adjustment gains computation, depend intrinsically on the MERMAID matchups and as such it is essential to ensure the quality of in-situ irradiance data. Results indicated the need to include in MERMAID 'homogenised' versions of datasets (consistent with MERIS assumptions), and stressed the need to investigate further the potential for tilt correction of Es.

  14. Wind estimates from cloud motions - Preliminary results from phases I, II and III of an in situ aircraft verification experiment

    NASA Technical Reports Server (NTRS)

    Hasler, A. F.; Shenk, W. E.; Skillman, W. C.

    1976-01-01

    The accuracy of wind estimates derived from cloud motion is under investigation. Aircraft measurements of the ambient wind field have been compared with simultaneous inertial navigation system descriptions of the extent and motion of 40 tropical cumulus and 5 cirrus clouds. Preliminary results indicate that cloud-motion wind estimates are sufficiently accurate to be used in sensitive divergence, vorticity, and vertical motion calculations. The magnitude of the vector difference between the cirrus cloud velocity and the mean wind of the cloud layer was found to be about 1.6 m/sec. The major source of error is thought to be in determination of the position of the cloud. In the case of cumulus clouds, the magnitude of the vector difference between the aircraft-measured cloud motion and the cloud-base wind is less than 1.3 m/sec.

  15. In situ analysis of measurements of auroral dynamics and structure

    NASA Astrophysics Data System (ADS)

    Mella, Meghan R.

    Two auroral sounding rocket case studies, one in the dayside and one in the nightside, explore aspects of poleward boundary aurora. The nightside sounding rocket, Cascades-2 was launched on 20 March 2009 at 11:04:00 UT from the Poker Flat Research Range in Alaska, and flew across a series of poleward boundary intensifications (PBIs). Each of the crossings have fundamentally different in situ electron energy and pitch angle structure, and different ground optics images of visible aurora. The different particle distributions show signatures of both a quasistatic acceleration mechanism and an Alfvenic acceleration mechanism, as well as combinations of both. The Cascades-2 experiment is the first sounding rocket observation of a PBI sequence, enabling a detailed investigation of the electron signatures and optical aurora associated with various stages of a PBI sequence as it evolves from an Alfvenic to a more quasistatic structure. The dayside sounding rocket, Scifer-2 was launched on 18 January 2008 at 7:30 UT from the Andoya Rocket Range in Andenes, Norway. It flew northward through the cleft region during a Poleward Moving Auroral Form (PMAF) event. Both the dayside and nightside flights observe dispersed, precipitating ions, each of a different nature. The dispersion signatures are dependent on, among other things, the MLT sector, altitude, source region, and precipitation mechanism. It is found that small changes in the shape of the dispersion have a large influence on whether the precipitation was localized or extended over a range of altitudes. It is also found that a single Maxwellian source will not replicate the data, but rather, a sum of Maxwellians of different temperature, similar to a Kappa distribution, most closely reproduces the data. The various particle signatures are used to argue that both events have similar magnetospheric drivers, that is, Bursty Bulk Flows in the magnetotail.

  16. Wind estimates from cloud motions: Preliminary results from phases 1, 2, and 3 of an in situ aircraft verification experiment

    NASA Technical Reports Server (NTRS)

    Hasler, A. F.; Shenk, W. E.; Skillman, W. C.

    1975-01-01

    Low level aircraft equipped with Inertial Navigation Systems (INS) were used to define the vertical extent and horizontal motion of a cloud and to measure the ambient wind field. A high level aircraft, also equipped with an INS, took photographs to describe the horizontal extent of the cloud field and to measure cloud motion. The aerial photographs were also used to make a positive identification in a satellite picture of the cloud observed by the low level aircraft. The experiment was conducted over the tropical oceans in the vicinity of Florida, Puerto Rico, Panama and in the Western Gulf of Mexico. Results for tropical cumulus clouds indicate excellent agreement between the cloud motion and the wind at the cloud base. The magnitude of the vector difference between the cloud motion and the cloud base wind is less than 1.3 m/sec for 67% of the cases with track lengths of 1 hour or longer. The cirrus cloud motions agreed best with the mean wind in the cloud layer with a vector difference of about 1.6 m/sec.

  17. Measurements of neutron radiation in aircraft.

    PubMed

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

    2010-12-01

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

  18. Linking surface in-situ measurements to columnar aerosol optical properties at Hyytiälä, Finland

    NASA Astrophysics Data System (ADS)

    Zieger, P.; Aalto, P.; Aaltonen, V.; Äijälä, M.; Backman, J.; Ehn, M.; Hong, J.; Krejci, R.; Laborde, M.; de Leeuw, G.; Petäjä, T.; Pfüller, A.; Rosati, B.; Tesche, M.; Väänänen, R.

    2014-12-01

    Ambient optical properties of aerosols strongly depend on the particles' hygroscopicity and the relative humidity (RH) of the surrounding air. The key parameter to describe the influence of RH on the particle light scattering is the scattering enhancement factor f(RH), which is defined as the particle light scattering coefficient at defined RH divided by its dry value. Knowledge of this hygroscopicity effect is of crucial importance for climate forcing calculations and is needed for the comparison or validation of remote sensing with in-situ measurements. We will present results of an intensive field campaign carried out in summer 2013 at the SMEAR II station in Hyytiälä, Finland, which was part of the EU-FP7 project PEGASOS (Pan-European Gas-Aerosols-climate interaction Study). Ground-based and airborne measurements of aerosol optical, chemical and microphysical properties were conducted. The f(RH) measured at ground by a humidified nephelometer was found to be significantly lower (1.53 ± 0.24 at RH=85% and wavelength λ=450 nm) than observed at other European sites (Zieger et al., 2013). One reason is the high organic mass fraction of the boreal aerosol as measured by an aerosol chemical speciation monitor (ACSM). A closure study using Mie theory showed the consistency of the ground based in-situ measurements. Our measurements allowed to determine the ambient particle light extinction coefficient. Together with intensive aircraft measurements (lasting one month) of the particle number size distribution and ambient humidity, different columnar values were determined and compared to direct measurements and inversions of the AERONET Sun photometer (e.g., the columnar aerosol volume size distribution). The aerosol optical depth strongly correlated (R2≈0.9 for λ=440 nm to R2≈0.6 for λ=1020 nm) with the in situ derived values, but was significantly lower compared to the direct measurements of the Sun photometer (slope ≈0.5). This was explained by the loss of

  19. Method and apparatus for in-situ detection and isolation of aircraft engine faults

    NASA Technical Reports Server (NTRS)

    Bonanni, Pierino Gianni (Inventor); Brunell, Brent Jerome (Inventor)

    2007-01-01

    A method for performing a fault estimation based on residuals of detected signals includes determining an operating regime based on a plurality of parameters, extracting predetermined noise standard deviations of the residuals corresponding to the operating regime and scaling the residuals, calculating a magnitude of a measurement vector of the scaled residuals and comparing the magnitude to a decision threshold value, extracting an average, or mean direction and a fault level mapping for each of a plurality of fault types, based on the operating regime, calculating a projection of the measurement vector onto the average direction of each of the plurality of fault types, determining a fault type based on which projection is maximum, and mapping the projection to a continuous-valued fault level using a lookup table.

  20. Airborne in-situ investigations of the Eyjafjallajökull volcanic ash plume on Iceland and over north-western Germany with light aircrafts and optical particle counters

    NASA Astrophysics Data System (ADS)

    Weber, K.; Eliasson, J.; Vogel, A.; Fischer, C.; Pohl, T.; van Haren, G.; Meier, M.; Grobéty, B.; Dahmann, D.

    2012-03-01

    During the time period of the eruption of the Icelandic volcano Eyjafjallajökull in April/May 2010 the Duesseldorf University of Applied Sciences has performed 14 research flights in situations with and without the volcanic ash plume over Germany. In parallel to the research flights in Germany three measurement flights have been performed by the University of Iceland in May 2010 over the western part of Iceland. During two of these flights the outskirts of the eruption plume were entered directly, delivering most direct measurements within the eruption plume during this eruptive event. For all the measurement flights reported here, light durable piston-motor driven aircrafts were used, which were equipped with optical particle counters for in-situ measurements. Real-time monitoring of the particle concentrations was possible during the flights. As different types of optical particle counters have been used in Iceland and Germany, the optical particle counters have been re-calibrated after the flights to the same standard using gravimetric reference methods and original Eyjafjallajökull volcanic ash samples. In-situ measurement results with high spatial resolution, directly from the eruption plume in Iceland as well as from the dispersed and several days old plume over Germany, are therefore presented here for the first time. They are normalized to the same ash concentration calibration standard. Moreover, airborne particles could be sampled directly out of the eruption plume in Iceland as well as during the flights over Germany. During the research flights over Iceland from 9 May 2011 to 11 May 2011 the ash emitted from the vent of the volcano turned out to be concentrated in a narrow well-defined plume of about 10 km width at a distance of 45-60 km away from the vent. Outside this plume the airborne ash concentrations could be proved to be below 50 μg m -3 over western Iceland. However, by entering the outskirts of the plume directly the research aircraft could

  1. The validation of ATSR measurements with in situ sea temperatures

    SciTech Connect

    Minnett, P.J.; Stansfield, K.L.

    1993-10-08

    The largest source of uncertainty in the retrieval of SST (sea-surface) temperature from space-borne infrared radiometric measurements is in the correction for the effects of the intervening atmosphere. During a research cruise of the R/V Alliance measurements of sea surface temperature, surface meteorological variables and surface infrared radiances were taken. SST fields were generated from the ATSR data using pre-launch algorithims derived by the ATSR Instrument Team (A.M. Zavody, personal communication), and the initial comparison between ATSR measurements and SST taken along the ship`s track indicate that the dual-angle atmospheric correction is accurate in mid-latitude conditions.

  2. Power Measurement Errors on a Utility Aircraft

    NASA Technical Reports Server (NTRS)

    Bousman, William G.

    2002-01-01

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

  3. In situ measurements of IO and reactive iodine aboard the RV Sonne during SHIVA

    NASA Astrophysics Data System (ADS)

    Heard, Dwayne; Walker, Hannah; Ingham, Trevor; Huang, Ru-Jin; Wittrock, Folker

    2013-04-01

    Halogenated very short-lived substances (VSLS) are emitted from the oceans by marine species such as macroalgae and phytoplankton and contribute to halogen loading in the troposphere and lower stratosphere. The SHIVA (Stratospheric Ozone: Halogen Impacts in a Varying Atmosphere) project combined ship-borne, aircraft-based and ground-based measurements in and over the South China Sea and the Sulu Sea, and around the coast of Malaysian Borneo. In this paper we present measurements of IO radicals in coastal and open ocean regions made onboard the German research vessel RV Sonne in November 2011 between Singapore and Manila, via the northern coast of Malaysian Borneo (South China Sea) and the Sulu Sea. In situ measurements of IO were made on 12 days by the University of Leeds laser-induced fluorescence (LIF) instrument, with a detection limit of 0.3 pptv for a 30 minute averaging period. The cruise average IO concentration was found to be 1.2 pptv, with a maximum concentration of 2.4 pptv in the middle of the Sulu Sea, an area known for high biological activity. Only a weak diurnal profile was observed, with IO detected above the detection limit on 10 out of the 11 nights when the LIF instrument was operational. Measurements of IO at night in the open ocean have not previously been reported and indicate the presence of gas phase or heterogeneous mechanisms that recycle iodine species without requiring light. There was reasonable agreement for IO concentrations measured by the University of Leeds LIF and the University of Bremen MAX-DOAS instruments, for which a comparison will be presented. I2, ICl and HOI were measured by the University of Mainz using a coupled diffusion denuder system followed by analysis using gas chromatography coupled with ion trap mass spectroscopy, with a detection of 0.17 pptv for 30 mins (I2). The cruise average I2 concentration was found to be 2.0 pptv, with a maximum concentration observed during one night of 12.7 pptv on the northern coast

  4. In Situ Leaf Level Gas Exchange Measurements, Barrow, Alaska, 2013

    DOE Data Explorer

    Alistair Rogers; Stefanie Lasota

    2015-01-13

    Survey measurements of photosynthetic rate and stomatal conductance together with carbon dioxide concentration, temperature, PAR, and relative humidity for 8 species on the BEO. Previously titled "Plant Physiology Data, Barrow, Alaska, 2013"

  5. Evaluation of Terms in the Water Vapor Budget Using Airborne Dial and In Situ Measurements from the Southern Great Plans 1997 Experiment

    NASA Technical Reports Server (NTRS)

    Senff, Christoph J.; Davis, Kenneth J.; Lenschow, Donald H.; Browell, Edward V.; Ismail, Syed

    1998-01-01

    The Southern Great Plains (SGP97) field experiment was conducted in Oklahoma during June and July 1997 primarily to validate soil moisture retrieval algorithms using microwave radiometer measurements from aircraft as well as in situ surface measurements. One important objective of the SGP97 experiment plan was to examine the effect of soil moisture on the evolution of the atmospheric boundary layer (ABL) and clouds over the Southern Great Plains during the warm season. To support boundary layer studies during SGP97. the NASA Langley Research Center's Lidar Atmospheric Sensing Experiment (LASE) was flown on a NASA-P3 aircraft in conjunction with the Electronically Scanned Thinned Array Radiometer (ESTAR). The LASE instrument is an airborne, downward-looking differential absorption lidar (DIAL) system capable of measuring water vapor concentration as well as aerosol backscatter with high horizontal and vertical resolution in the ABL. Here, we will demonstrate how the LASE data can be used to determine water vapor statistics and most of the water vapor budget terms in the ABL. This information can then be related to spatial variations in soil moisture and the surface energy budget. The extensive surface and aircraft in situ measurements conducted during SGP97 provide information on the ABL that cannot be retrieved from the LASE data alone and also offer an excellent opportunity to validate the remote water vapor budget measurements with LASE.

  6. A model-based framework for the quality assessment of surface albedo in situ measurement protocols

    NASA Astrophysics Data System (ADS)

    Adams, Jennifer; Gobron, Nadine; Widlowski, Jean-Luc; Mio, Corrado

    2016-09-01

    Satellite-based retrievals of land surface albedo are essential for climate and environmental modelling communities. To be of use, satellite-retrievals are required to comply to given accuracy requirements, mainly achieved through comparison with in situ measurements. Differences between in situ and satellite-based retrievals depend on their actual difference and their associated uncertainties. It is essential that these uncertainties can be computed to properly understand the differences between satellite-based and in situ measurements of albedo, however quantifying the individual contributions of uncertainty is difficult. This study introduces a model-based framework for assessing the quality of in situ albedo measurements. A 3D Monte Carlo Ray Tracing (MCRT) radiative transfer model is used to simulate field measurements of surface albedo, and is able to identify and quantify potential sources of error in the field measurement. Compliance with the World Meteorological Organisation (WMO) requirement for 3% accuracy is tested. 8 scenarios were investigated, covering a range of ecosystem types and canopy structures, seasons, illumination angles and tree heights. Results indicate that height of measurement above the canopy is the controlling factor in accuracy, with each canopy scenario reaching the WMO requirement at different heights. Increasing canopy heterogeneity and tree height noticeably reduces the accuracy, whereas changing seasonality from summer to winter in a deciduous forest increases accuracy. For canopies with a row structure, illumination angle can significantly impact accuracy as a result of shadowing effects. Tests were made on the potential use of multiple in situ measurements, indicating considerably increased accuracy if two or more in situ measurements can be made.

  7. Acoustic backscattering by deepwater fish measured in situ from a manned submersible

    NASA Astrophysics Data System (ADS)

    Benoit-Bird, Kelly J.; Au, Whitlow W. L.; Kelley, Christopher D.; Taylor, Christopher

    2003-02-01

    An outstanding problem in fisheries acoustics is the depth dependence of scattering characteristics of swimbladder-bearing fish, and the effects of pressure on the target strength of physoclistous fish remain unresolved. In situ echoes from deepwater snappers were obtained with a sonar transducer mounted on a manned submersible next to a low-light video camera, permitting simultaneous echo recording and identification of species, fish size and orientation. The sonar system, consisting of a transducer, single board computer, hard disk, and analog-to-digital converter, used a 80 μs, broadband signal (bandwidth 35 kHz, center frequency 120 kHz). The observed relationship between fish length and in situ target strength shows no difference from the relationship measured at the surface. No differences in the species-specific temporal echo characteristics were observed between surface and in situ measures. This indicates that the size and shape of the snappers' swimbladders are maintained both at the surface and at depths of up to 250 m. Information obtained through controlled backscatter measurements of tethered, anesthetized fish at the surface can be applied to free-swimming fish at depth. This is the first published account of the use of a manned submersible to measure in situ scattering from identified, individual animals with known orientations. The distinct advantage of this technique compared with other in situ techniques is the ability to observe the target fish, obtaining accurate species, size, and orientation information.

  8. The HUMSAT System: a CubeSat-based Constellation for In-situ and Inexpensive Environmental Measurements

    NASA Astrophysics Data System (ADS)

    Tubío-Pardavila, R.; Vigil, S. A.; Puig-Suari, J.; Aguado Agelet, F.

    2014-12-01

    There is a requirement for low cost in-situ measurements of environmental parameters such as air quality, meteorological data, and water quality in remote areas. Currently available solutions for such measurements include remote sensing from satellite and aircraft platforms, and in-situ measurements from mobile and aircraft platforms. Fixed systems such as eddy covariance networks, tall towers, and the Total Carbon Column Observing Network (TCCON) are providing precision greenhouse gas measurements. Within this context, the HUMSAT system designed by the University of Vigo (Spain) will complement existing high-precision measurement systems with low cost in-situ ground based sensors in remote locations using a constellation of CubeSats as a communications relay. The HUMSAT system standardizes radio communications in between deployed sensors and the CubeSats of the constellation, which act as store and forward satellites to ground stations for uploading to the internet. Current ground stations have been established at the University of Vigo (Spain) and California Polytechnic State University (Cal Poly). Users of the system may deploy their own environmental sensors to meet local requirements. The sensors will be linked to a low-cost satellite data transceiver using a standard HUMSAT protocol. The transceiver is capable of receiving data from the HUMSAT constellation to remotely reconfigure sensors without the need of physically going to the sensor location. This transceiver uses a UHF channel around 437 MHz to exchange short data messages with the sensors. These data messages can contain up to 32 bytes of useful information and are transmitted at a speed around 300 bps. The protocol designed for this system handles the access to the channel by all these elements and guarantees a correct transmission of the information in such an scenario. The University of Vigo has launched the first satellite of the constellation, the HUMSAT-D CubeSat in November 2013 and has

  9. Measurement of hydrogen peroxide from aircraft

    SciTech Connect

    Kok, G.L.

    1980-01-01

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

  10. In situ performance curves measurements of large pumps

    NASA Astrophysics Data System (ADS)

    Anton, A.

    2010-08-01

    The complex energetic system on the river Lotru in Romania comprises of a series of lakes and pumping stations and a major hydroelectric power plant: Lotru-Ciunget. All the efforts have been oriented towards the maintenance of the Pelton turbines and very little attention has been directed to the pumps. In the system, there are three large pumping stations and only in the last 5 years, the pump performances have become a concern. The performances where determined using portable ultrasonic flow meters, a Yates meter, precision manometers and appropriate electrical equipment for power measurement (Power Analiser - NORMA D4000 LEM). The measurements are not supposed to interfere with the normal operation so only a limited number of tests could be performed. Based on those tests, portions of the test curves have been measured and represented in specific diagrams.

  11. In-Situ Measurements of Fabric Thickness Evolution During Draping

    SciTech Connect

    Ivanov, D. S.; Van Gestel, C.; Lomov, S. V.; Verpoest, I.

    2011-05-04

    The paper presents results of experimental program aimed at measuring fabric thickening while draping. The thickness evolution is important factor in resin infusion manufacturing where the resultant composite thickness is not controlled. The measurements are conducted by means of laser distance sensors adapted to the picture frame testing. Several carbon fabrics of very different architectures have been tested. Additionally, the pretension of the carbon fabric due to the gripping has been estimated by means of digital image correlation technique and an attempt to discuss the results obtained on different set-ups is made.

  12. Review of Techniques for Measuring Soil Moisture In situ.

    DTIC Science & Technology

    1980-08-01

    tested and sensor (1965) showed that modern improvements in the calibration, technique, such as using of Peltier devices for 3. Size of the sensitive...rays in measuring water con- Marais, P C and W B. De V Smit (1%2) Effet t of bulk density tent and permeability in unsaturated columns of :iI and of

  13. In situ thermal conductivity measurements of Titan's lower atmosphere

    NASA Astrophysics Data System (ADS)

    Hathi, B.; Ball, A. J.; Banaszkiewicz, M.; Daniell, P. M.; Garry, J. R. C.; Hagermann, A.; Leese, M. R.; Lorenz, R. D.; Rosenberg, P. D.; Towner, M. C.; Zarnecki, J. C.

    2008-10-01

    Thermal conductivity measurements, presented in this paper (Fig. 3), were made during the descent of the Huygens probe through the atmosphere of Titan below the altitude of 30 km. The measurements are broadly consistent with reference values derived from the composition, pressure and temperature profiles of the atmosphere; except in narrow altitude regions around 19 km and 11 km, where the measured thermal conductivity is lower than the reference by 1% and 2%, respectively. Only single data point exists at each of the two altitudes mentioned above; if true however, the result supports the case for existence for molecules heavier than nitrogen in these regions (such as: ethane, other primordial noble gases, carbon dioxide, and other hydrocarbon derivatives). The increasing thermal conductivity observed below 7 km altitude could be due to some liquid deposition during the descent; either due to condensation and/or due to passing through layers of fog/cloud containing liquid nitrogen-methane. Thermal conductivity measurements do not allow conclusions to be drawn about how such liquid may have entered the sensor, but an estimate of the cumulative liquid content encountered in the last 7 km is 0.6% by volume of the Titan's atmosphere sampled during descent.

  14. Rock matrix diffusivity determinations by in-situ electrical conductivity measurements.

    PubMed

    Ohlsson, Y; Löfgren, M; Neretnieks, I

    2001-02-01

    A fast method to determine rock matrix diffusion properties directly in the bedrock would be valuable in the investigation of a possible site for disposal of nuclear waste. An "effective diffusivity borehole log" would provide important information on the variability of this entity over the area studied. As opposed to traditional matrix diffusion laboratory experiments, electrical conductivity measurements are fast, inexpensive and also easy to carry out in-situ. In this study, electrical resistivity data from borehole logging, as well as from measurements on the actual core, is evaluated with the purpose of extracting matrix diffusivity data. The influence of migration of ions in the electrical double layer, which can be of great importance in low ionic strength pore water, is also considered in evaluating the in-situ data to accurately determine the effective pore diffusivity. The in-situ data compare fairly well to those measured in the rock core.

  15. In Situ ATP Bioluminescent Measurements in Subglacial Environments - The Engabreen Glacier in the Norwegian Arctic

    NASA Astrophysics Data System (ADS)

    Cullen, D. C.; Wadham, J. L.; Pancost, R.; Kelly, S.; Barnett, M. J.; Jackson, M.

    2007-12-01

    Engabreen is a northern outlet glacier from the western Svartisen ice cap on the Nordland coast of Norway just inside the Arctic Circle. A unique feature of the glacier is a man-made tunnel system within the bedrock beneath the glacier that offers scientists direct access to the glacier-bedrock interface. This unique facility - called the Engabreen Subglacial Laboratory - is ideal to test developments of new in situ analytical techniques. We have used the facility to perform the first in situ detection of microbial life in a subglacial environment using standard off-the-shelf ATP bioluminescence detection technology and therefore using ATP levels as a proxy of microbial life. Measurements were performed both in melt-waters in the tunnels and from melted ice samples directly from the glacier-bedrock interface. Levels of ATP above background were detected and appeared to be associated with suspended sediment particles rather than in the water or ice component. This indicated the presence of microbial life. Development of protocols for in situ sample processing and use of in situ ATP measurements in the directing and choice of sampling points for other techniques was explored. This study has shown that off-the-shelf portable ATP bioluminescence can be used to perform in situ measurements within sub-glacial environments but that further development work is required to optimize experimental protocols and to correlate findings with other life detection and enumeration techniques.

  16. Disassembling "evapotranspiration" in-situ with a complex measurement tool

    NASA Astrophysics Data System (ADS)

    Chormanski, Jaroslaw; Kleniewska, Malgorzata; Berezowski, Tomasz; Sporak-Wasilewska, Sylwia; Okruszko, Tomasz; Szatylowicz, Jan; Batelaan, Okke

    2014-05-01

    In this work we present a complex tool for measuring water fluxes in wetland ecosystems. The tool was designed to quantify processes related to interception storage on plants leafs. The measurements are conducted by combining readings from various instruments, including: eddy covariance tower (EC), field spectrometer, SapFlow system, rain gauges above and under canopy, soil moisture probes and other. The idea of this set-up is to provide continuous measurement of overall water flux from the ecosystem (EC tower), intercepted water volume and timing (field spectrometers), through-fall (rain gauges above and under canopy), transpiration (SapFlow), evaporation and soil moisture (soil moisture probes). Disassembling the water flux to the above components allows giving more insight to the interception related processes and differentiates them from the total evapotranspiration. The measurements are conducted in the Upper Biebrza Basin (NE Poland). The study area is part of the valley and is covered by peat soils (mainly peat moss with the exception of areas near the river) and receives no inundations waters of the Biebrza. The plant community of Agrostietum-Carici caninae has a dominant share here creating an up to 0.6 km wide belt along the river. The area is covered also by Caricion lasiocarpae as well as meadows and pastures Molinio-Arrhenatheretea, Phragmitetum communis. Sedges form a hummock pattern characteristic for the sedge communities in natural river valleys with wetland vegetation. The main result of the measurement set-up will be the analyzed characteristics and dynamics of interception storage for sedge ecosystems and a developed methodology for interception monitoring by use spectral reflectance technique. This will give a new insight to processes of evapotranspiration in wetlands and its components transpiration, evaporation from interception and evaporation from soil. Moreover, other important results of this project will be the estimation of energy and

  17. Enzymatic method for measuring starch gelatinization in dry products in situ

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An enzymatic method based on hydrolysis of starch by amyloglucosidase and measurement of D-glucose released by glucose oxidase-peroxidase was developed to measure both gelatinized starch and hydrolyzable starch in situ of dried starchy products. Efforts focused on the development of sample handling ...

  18. Identifying a Sea Breeze Circulation Pattern Over the Los Angeles Basin Using Airborne In Situ Carbon Dioxide Measurements

    NASA Astrophysics Data System (ADS)

    Brannan, A. L.; Schill, S.; Trousdell, J.; Heath, N.; Lefer, B. L.; Yang, M. M.; Bertram, T. H.

    2014-12-01

    The Los Angeles Basin in Southern California is an optimal location for a circulation study, due to its location between the Pacific Ocean to the west and the Santa Monica and San Gabriel mountain ranges to the east, as well as its booming metropolitan population. Sea breeze circulation carries air at low altitudes from coastal to inland regions, where the air rises and expands before returning back towards the coast at higher altitudes. As a result, relatively clean air is expected at low altitudes over coastal regions, but following the path of sea breeze circulation should increase the amount of anthropogenic influence. During the 2014 NASA Student Airborne Research Program, a highly modified DC-8 aircraft completed flights from June 23 to 25 in and around the LA Basin, including missed approaches at four local airports—Los Alamitos and Long Beach (coastal), Ontario and Riverside (inland). Because carbon dioxide (CO2) is chemically inert and well-suited as a conserved atmospheric tracer, the NASA Langley Atmospheric Vertical Observations of CO2 in the Earth's Troposphere (AVOCET) instrument was used to make airborne in situ carbon dioxide measurements. Combining measured wind speed and direction data from the aircraft with CO2 data shows that carbon dioxide can be used to trace the sea breeze circulation pattern of the Los Angeles basin.

  19. Airborne In-Situ Measurements of Aerosol and Cloud Microphysical Properties in Mixed-Phase Clouds Under Varying Conditions

    NASA Astrophysics Data System (ADS)

    Comstock, J. M.; Fan, J.; Tomlinson, J. M.; Mei, F.; Hubbe, J. M.; Schmid, B.

    2014-12-01

    Cloud microphysical properties impact the interaction of clouds and radiation in the atmosphere, and can influence atmospheric circulations through changes in cloud phase. Characterizing the conditions that control phase changes and the microphysical properties of mixed-phase clouds is important for improving understanding of physical processes that influence cloud phase. We characterize the aerosol and cloud microphysical properties in relation to the atmospheric dynamic and thermodynamic conditions observed in mixed-phase clouds during several aircraft-based field experiments. The Department of Energy Atmospheric Radiation Measurement program's Gulfstream-1 aircraft was used to sample aerosol and cloud properties in warm and cold clouds during several recent field experiments. We analyze in-situ observations from the CalWater and TCAP field campaigns to examine the variability of cloud properties (phase, hydrometeor size, ice and liquid water content, particle habit) with changes in aerosol, vertical velocity, and temperature. These measurements indicate that in addition to aerosol concentration, vertical velocity strength has important influence on cloud phase in mixed-phase cloud regimes.

  20. In situ granular charge measurement by free-fall videography

    NASA Astrophysics Data System (ADS)

    Waitukaitis, S. R.; Jaeger, H. M.

    2013-02-01

    We present the design and performance characterization of a new experimental technique for measuring individual particle charges in large ensembles of macroscopic grains. The measurement principle is qualitatively similar to that used in determining the elementary charge by Millikan in that it follows individual particle trajectories. However, by taking advantage of new technology we are able to work with macroscopic grains and achieve several orders of magnitude better resolution in charge to mass ratios. By observing freely falling grains accelerated in a horizontal electric field with a co-falling, high-speed video camera, we dramatically increase particle tracking time and measurement precision. Keeping the granular medium under vacuum, we eliminate air drag, leaving the electrostatic force as the primary source of particle accelerations in the co-moving frame. Because the technique is based on direct imaging, we can distinguish between different particle types during the experiment, opening up the possibility of studying charge transfer processes between different particle species. For the ˜300 μm diameter grains reported here, we achieve an average acceleration resolution of ˜0.008 m/s2, a force resolution of ˜500 pN, and a median charge resolution ˜6× 104 elementary charges per grain (corresponding to surface charge densities ˜1 elementary charges per μm2). The primary source of error is indeterminacy in the grain mass, but with higher resolution cameras and better optics this can be further improved. The high degree of resolution and the ability to visually identify particles of different species or sizes with direct imaging make this a powerful new tool to characterize charging processes in granular media.

  1. In situ granular charge measurement by free-fall videography.

    PubMed

    Waitukaitis, S R; Jaeger, H M

    2013-02-01

    We present the design and performance characterization of a new experimental technique for measuring individual particle charges in large ensembles of macroscopic grains. The measurement principle is qualitatively similar to that used in determining the elementary charge by Millikan in that it follows individual particle trajectories. However, by taking advantage of new technology we are able to work with macroscopic grains and achieve several orders of magnitude better resolution in charge to mass ratios. By observing freely falling grains accelerated in a horizontal electric field with a co-falling, high-speed video camera, we dramatically increase particle tracking time and measurement precision. Keeping the granular medium under vacuum, we eliminate air drag, leaving the electrostatic force as the primary source of particle accelerations in the co-moving frame. Because the technique is based on direct imaging, we can distinguish between different particle types during the experiment, opening up the possibility of studying charge transfer processes between different particle species. For the ∼300 μm diameter grains reported here, we achieve an average acceleration resolution of ∼0.008 m/s(2), a force resolution of ∼500 pN, and a median charge resolution ∼6× 10(4) elementary charges per grain (corresponding to surface charge densities ∼1 elementary charges per μm(2)). The primary source of error is indeterminacy in the grain mass, but with higher resolution cameras and better optics this can be further improved. The high degree of resolution and the ability to visually identify particles of different species or sizes with direct imaging make this a powerful new tool to characterize charging processes in granular media.

  2. The principles of dielectric measurements for in situ monitoring of composite processing

    NASA Astrophysics Data System (ADS)

    Mijovic, Jovan; Kenny, Jose M.; Maffezzoli, Alfonso; Trivisano, Antonio; Bellucci, Francesco; Nicolais, Luigi

    The fundamental concepts of dielectric behavior of polymers and the utilization of dielectric measurements for in situ monitoring of cure of polymers and composites are discussed. Information is presented on currently used dielectric sensors and the procedure for calculation of dielectric parameters from the monitored signal. The review is written to accommodate both the fundamental and the pragmatic aspects of dielectric monitoring of cure. In the final part of the review, a critical assessment is offered of the advantages and disadvantages of dielectric measurements for the in situ monitoring of processing of polymers and composites.

  3. First in-situ lattice strains measurements under load at VULCAN

    SciTech Connect

    An, Ke; Skorpenske, Harley David; Stoica, Alexandru Dan; Wang, Xun-Li; Cakmak, Ercan

    2011-01-01

    The engineering materials diffractometer, VULCAN, at the Spallation Neutron Source began commissioning on June 26, 2009. This instrument is designed for materials science and engineering studies. In situ lattice strain measurements of a model metallic material under monotonic tensile load have been performed on VULCAN. The tensile load was applied under two different strain rates, and neutron diffraction measurements were carried out in both high-intensity and high-resolution modes. These experiments demonstrated VULCAN's in situ study capability of deformation behaviors even during the early phases of commissioning.

  4. 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.

  5. In situ seismic measurements in claystone at Tournemire (France)

    NASA Astrophysics Data System (ADS)

    Zillmer, M.; Marthelot, J.-M.; Gélis, C.; Cabrera, J.; Druivenga, G.

    2014-12-01

    Compressional and shear wave seismic measurements were performed in an old railway tunnel and in galleries excavated in a 250-m-thick Toarcian claystone formation in the Tournemire experimental station (France). Three component (3C) geophones and three orthogonal orientations of the vibroseismic force source were used. Additionally, vertical seismic profiling (VSP) measurements were recorded with a 3C borehole geophone, a hydrophone and a microphone in a 159 m deep borehole (ID180) in the tunnel. The seismic data show that Toarcian claystone has strong transverse isotropy (TI) with a vertical symmetry axis. The qP, SH and qSV wave propagation velocities in horizontal directions-the plane of isotropy of the TI medium-are measured as 3550, 1850 and 1290 m s-1, respectively. The zero-offset VSP reveals that only one shear wave propagates in the vertical (depth) direction and the P- and S-wave velocities are 3100 and 1375 m s-1, respectively. Four elastic moduli of the TI medium are determined from the seismic velocities and from the bulk density of 2.53 g cm-3: c11 = 31.9 GPa, c33 = 24.3 GPa, c44 = 4.5 GPa and c66 = 8.7 GPa. A walkaway VSP with the borehole geophone at 50 m depth in borehole ID180 and shot points in the galleries leads to oblique seismic ray paths which allow us to determine the fifth elastic modulus of the TI medium to c13 = 16 GPa. The tube wave recorded by a hydrophone in the water filled lower part of the borehole propagates with 1350 m s-1, which confirms the estimate of the elastic constant c66. The analysis of body wave and surface wave data from a seismic experiment in Galerie Est shows reflections from several fracture zones in the gallery floor. The thickness of the excavation damaged zone (EDZ) in the floor of Galerie Est is estimated to 0.7 m.

  6. Magnetic Susceptibility Measurements for in Situ Characterization of Lunar Soil

    NASA Technical Reports Server (NTRS)

    Oder, R. R.

    1992-01-01

    Magnetic separation is a viable method for concentration of components of lunar soils and rocks for use as feedstocks for manufacture of metals, oxygen, and for recovery of volatiles such as He-3. Work with lunar materials indicates that immature soils are the best candidates for magnetic beneficiation. The magnetic susceptibility at which selected soil components such as anorthite, ilmenite, or metallic iron are separated is not affected by soil maturity, but the recovery of the concentrated components is. Increasing soil maturity lowers recovery. Mature soils contain significant amounts of glass-encased metallic iron. Magnetic susceptibility, which is sensitive to metallic iron content, can be used to measure soil maturity. The relationship between the ratio of magnetic susceptibility and iron oxide and the conventional maturity parameter, I(sub s)/FeO, ferromagnetic resonant intensity divided by iron oxide content is given. The magnetic susceptibilities were determined using apparatus designed for magnetic separation of the lunar soils.

  7. In-situ Ground-Based and Airborne Formaldehyde Measurements in the Houston Area During TexAQS-II

    NASA Astrophysics Data System (ADS)

    Rappenglueck, B.; Byun, D.; Alvarez, S.; Buhr, M.; Coarfa, V.; Czader, B.; Dasgupta, P.; Estes, M.; Kim, S.; Leuchner, M.; Luke, W.; Shauck, M.; Zanin, G.

    2007-12-01

    Formaldehyde is considered to play a significant role in summertime photochemistry in the Houston area, in particular it is considered an important source for radicals. Secondary formation seems to be the most important fraction of ambient HCHO. Enhanced nighttime values may indicate primary sources. Potential sources may include mobile sources such as traffic exhaust, in particular not well maintained Diesel engines. Other possible sources may include point sources such as coffee roasting and flares from refineries. In this study we focused on the TexAQS-II continuous in-situ formaldehyde data set based on Hantzsch reaction which was obtained in the Ship Channel area (HRM3 and Lynchburg Ferry site) and at the Moody Tower for several weeks. We also include in-situ HCHO measurements obtained with the same technique aboard the Baylor aircraft during TexAQS-II flight missions. Formaldehyde data was compared to several trace gases that are supposed to be coemitted including CO (traffic), ethylene (flares), and SO2 (industry). In order to keep photochemical processes at a minimum special focus was on nighttime data. Case studies will be discussed where meteorological conditions including recirculation and boundary layer developments seem to play a major role in the redistribution of HCHO. Observations will be compared to CMAQ model studies.

  8. Public transit bus ramp slopes measured in situ.

    PubMed

    Bertocci, Gina; Frost, Karen; Smalley, Craig

    2014-05-02

    Abstract Purpose: The slopes of fixed-route bus ramps deployed for wheeled mobility device (WhMD) users during boarding and alighting were assessed. Measured slopes were compared to the proposed Americans with Disabilities Act (ADA) maximum allowable ramp slope. Methods: A ramp-embedded inclinometer measured ramp slope during WhMD user boarding and alighting on a fixed-route transit bus. The extent of bus kneeling was determined for each ramp deployment. In-vehicle video surveillance cameras captured ramp deployment level (street versus sidewalk) and WhMD type. Results: Ramp slopes ranged from -4° to 15.5° with means of 4.3° during boarding (n = 406) and 4.2° during alighting (n = 405). Ramp slope was significantly greater when deployed to street level. During boarding, the proposed ADA maximum allowable ramp slope (9.5°) was exceeded in 66.7% of instances when the ramp was deployed to street level, and in 1.9% of instances when the ramp was deployed to sidewalk level. During alighting, the proposed ADA maximum allowable slope was exceeded in 56.8% of instances when the ramp was deployed to street level and in 1.4% of instances when the ramp was deployed to sidewalk level. Conclusions: Deployment level, built environment and extent of bus kneeling can affect slope of ramps ascended/descended by WhMD users when accessing transit buses. Implications for Rehabilitation Since public transportation services are critical for integration of wheeled mobility device (WhMD) users into the community and society, it is important that they, as well as their therapists, are aware of conditions that may be encountered when accessing transit buses. Knowledge of real world ramp slope conditions that may be encountered when accessing transit buses will allow therapists to better access capabilities of WhMD users in a controlled clinical setting. Real world ramp slope conditions can be recreated in a clinical setting to allow WhMD users to develop and practice necessary

  9. General purpose in-situ surface tension measurement

    NASA Astrophysics Data System (ADS)

    Lapham, Gary S.; Dowling, David R.; Schultz, William W.

    1996-11-01

    While the Wilhelmy method is over a century old, there is a need for clear hydrodynamic explanations for corrections to the basic weight-divided-by-slide-perimeter measurement. A technique tailored for a free surface with surfactants has been developed including the effects of hydrostatic pressure and for the angle that the free surface meets with the Wilhelmy plate. A two-dimensional hydrostatic analysis has captured much of the discrepency between the typically-applied simple model and experiments. However, three-dimensional end effects play an important role and add experimental uncertainty. To avoid these end effects, a circular geometry was used and compared to axisymmetric analysis. Unlike, the du Noüy ring, this apparatus has sharp corners and well-defined corrections. The technique can be used in any basin, with any liquid, and with any surface contamination condition provided the plate can be wetted. Experiments with standard Wilhelmy plates that prompted technique development and results from the new technique are discussed. This research is supported by the Office of Naval Research.

  10. In-situ measurement of the substorm onset instability

    NASA Astrophysics Data System (ADS)

    Murphy, K. R.; Rae, J.; Watt, C.; Forsyth, C.; Mann, I. R.; Yao, Z.; Kalmoni, N.

    2015-12-01

    The substorm is arguably the major mode of variability in near-Earth Space which unpredictably dissipates a considerable and variable amount of energy into the near-Earth magnetosphere and ionosphere. What process or processes determine when this energy is released is uncertain, although it is evident that both near-Earth plasma instability and magnetotail reconnection play a role in this energy release. Much emphasis has recently been placed on the role of magnetic reconnection in substorms, we focus here on observations of the unmistakeable signs of a plasma instability acting at substorm onset. Using data from the THEMIS spacecraft, we show that electromagnetic waves grow in the magnetotail at the expense of the local electron and ion thermal energy. The wave growth in space is the direct counterpart to the wave growth seen at the substorm onset location at the ionosphere, as measured by the CARISMA and THEMIS magnetometers and THEMIS all-sky-imagers. We present evidence that the free energy source for the instability is associated with the electron and ion thermal energy, and not the local electron or ion flow energy.

  11. Quantitative Imaging and In Situ Concentration Measurements of Quantum Dot Nanomaterials in Variably Saturated Porous Media

    DOE PAGES

    Uyuşur, Burcu; Snee, Preston T.; Li, Chunyan; ...

    2016-01-01

    Knowledge of the fate and transport of nanoparticles in the subsurface environment is limited, as techniques to monitor and visualize the transport and distribution of nanoparticles in porous media and measure their in situ concentrations are lacking. To address these issues, we have developed a light transmission and fluorescence method to visualize and measure in situ concentrations of quantum dot (QD) nanoparticles in variably saturated environments. Calibration cells filled with sand as porous medium and various known water saturation levels and QD concentrations were prepared. By measuring the intensity of the light transmitted through porous media exposed to fluorescent lightmore » and by measuring the hue of the light emitted by the QDs under UV light exposure, we obtained simultaneously in situ measurements of water saturation and QD nanoparticle concentrations with high spatial and temporal resolutions. Water saturation was directly proportional to the light intensity. A linear relationship was observed between hue-intensity ratio values and QD concentrations for constant water saturation levels. The advantages and limitations of the light transmission and fluorescence method as well as its implications for visualizing and measuring in situ concentrations of QDs nanoparticles in the subsurface environment are discussed.« less

  12. In situ and laboratory measurements of cold plasmas

    NASA Astrophysics Data System (ADS)

    Frederick-Frost, Kristen Mae

    Measurement of the ionospheric thermal particle population bridges the two different communities of ground-based radar and space-based rocket studies, which have the common goal of characterizing heavy ion transport in the cusp/cleft region. We report on the results of the SERSIO (Svalbard EISCAT Rocket Study of Ion Outflows) mission, which show broad-band-extremely-low-frequency wave-ion heating in an environment observed by the EISCAT (European Incoherent Scatter) radars to have enhanced thermal electron temperature and density, and inferred ion-acoustic activity. The SERSIO data raise questions about the effects of spacecraft charging and sheath formation on thermal particle data analysis. These questions determined the design requirements for a low energy laboratory plasma calibration facility which we built and have begun to use. We discuss the magnetron-based cylindrical resonant plasma source, which produces charged particles with ionospheric energies and densities. The plasmas created with this source have Debye lengths similar to those encountered on ionospheric rocket flights, creating an ideal environment for charging and sheath studies that inform future thermal flight detector design. We investigate electron sheath structures by varying ion to electron collection ratios. The non-monotonic electron sheaths obtained by embedding a positively biased electrode within the sheath of a more negative conductor are explored. These initial plasma ion and electron sheath investigations both clarify the behavior of a thermal electron detector previously flown, and explore a low density and long Debye length parameter regime that is under-studied in the laboratory.

  13. Column Closure Studies of Lower Tropospheric Aerosol and Water Vapor During ACE-Asia Using Airborne Sunphotometer, Airborne In-Situ and Ship-Based Lidar Measurements

    NASA Technical Reports Server (NTRS)

    Schmid, B.; Hegg, A.; Wang, J.; Bates, D.; Redemann, J.; Russells, P. B.; Livingston, J. M.; Jonsson, H. H.; Welton, E. J.; Seinfield, J. H.

    2003-01-01

    We assess the consistency (closure) between solar beam attenuation by aerosols and water vapor measured by airborne sunphotometry and derived from airborne in-situ, and ship-based lidar measurements during the April 2001 Asian Pacific Regional Aerosol Characterization Experiment (ACE-Asia). The airborne data presented here were obtained aboard the Twin Otter aircraft. Comparing aerosol extinction o(550 nm) from four different techniques shows good agreement for the vertical distribution of aerosol layers. However, the level of agreement in absolute magnitude of the derived aerosol extinction varied among the aerosol layers sampled. The sigma(550 nm) computed from airborne in-situ size distribution and composition measurements shows good agreement with airborne sunphotometry in the marine boundary layer but is considerably lower in layers dominated by dust if the particles are assumed to be spherical. The sigma(550 nm) from airborne in-situ scattering and absorption measurements are about approx. 13% lower than those obtained from airborne sunphotometry during 14 vertical profiles. Combining lidar and the airborne sunphotometer measurements reveals the prevalence of dust layers at altitudes up to 10 km with layer aerosol optical depth (from 3.5 to 10 km altitude) of approx. 0.1 to 0.2 (500 nm) and extinction-to-backscatter ratios of 59-71 sr (523 nm). The airborne sunphotometer aboard the Twin Otter reveals a relatively dry atmosphere during ACE- Asia with all water vapor columns less than 1.5 cm and water vapor densities w less than 12 g/cu m. Comparing layer water vapor amounts and w from the airborne sunphotometer to the same quantities measured with aircraft in-situ sensors leads to a high correlation (r(sup 3)=0.96) but the sunphotometer tends to underestimate w by 7%.

  14. Upper Mississippi embayment shallow seismic velocities measured in situ

    USGS Publications Warehouse

    Liu, Huaibao P.; Hu, Y.; Dorman, J.; Chang, T.-S.; Chiu, J.-M.

    1997-01-01

    for shallow sediment obtained from reflection, refraction, crosshole and downhole techniques have been obtained for sites at the northern end of the embayment basin. The present borehole data, however, are measured from sites representative of large areas in the Mississippi embayment. Therefore, they fill a gap in information needed for modeling the response of the embayment to destructive seismic shaking.

  15. A numerical study of a method for measuring the effective in situ sound absorption coefficient.

    PubMed

    Kuipers, Erwin R; Wijnant, Ysbrand H; de Boer, André

    2012-09-01

    The accuracy of a method [Wijnant et al., Proc. of ISMA 31, Leuven, Belgium (2010), Vol. 31] for measurement of the effective area-averaged in situ sound absorption coefficient is investigated. Based on a local plane wave assumption, this method can be applied to sound fields for which a model is not available. Investigations were carried out by means of finite element simulations for a typical case. The results show that the method is a promising method for determining the effective area-averaged in situ sound absorption coefficient in complex sound fields.

  16. Stratospheric free chlorine measured by balloon-borne in situ resonance fluorescence

    NASA Technical Reports Server (NTRS)

    Anderson, J. G.; Grassl, H. J.; Shetter, R. E.; Margitan, J. J.

    1980-01-01

    Eight balloon-borne in situ measurements of ClO in the stratosphere are analyzed and are compared with recent model calculations. While the use of in situ stratospheric studies of free radicals to test models by comparing observed and predicted concentration profiles is essential for a prognosis of changes in stratospheric ozone, resulting from future changes in stratospheric ozone, such studies provide only limited insight into the nature of stratospheric photochemistry, because natural variability and the large number of fast reactions which compete in the coupling among the key radicals frustrate a detailed comparison between a mean distribution provided by the models and an instantaneous distribution provided by a single observation.

  17. A transportable magnetic resonance imaging system for in situ measurements of living trees: the Tree Hugger.

    PubMed

    Jones, M; Aptaker, P S; Cox, J; Gardiner, B A; McDonald, P J

    2012-05-01

    This paper presents the design of the 'Tree Hugger', an open access, transportable, 1.1 MHz (1)H nuclear magnetic resonance imaging system for the in situ analysis of living trees in the forest. A unique construction employing NdFeB blocks embedded in a reinforced carbon fibre frame is used to achieve access up to 210 mm and to allow the magnet to be transported. The magnet weighs 55 kg. The feasibility of imaging living trees in situ using the 'Tree Hugger' is demonstrated. Correlations are drawn between NMR/MRI measurements and other indicators such as relative humidity, soil moisture and net solar radiation.

  18. Utilizing The Synergy of Airborne Backscatter Lidar and In-Situ Measurements for Evaluating CALIPSO

    NASA Astrophysics Data System (ADS)

    Tsekeri, Alexandra; Amiridis, Vassilis; Marenco, Franco; Marinou, Eleni; Rosenberg, Phil; Solomos, Stavros; Trembath, Jamie; Allan, James; Bacak, Asan; Nenes, Athanasios

    2016-06-01

    Airborne campaigns dedicated to satellite validation are crucial for the effective global aerosol monitoring. CALIPSO is currently the only active remote sensing satellite mission, acquiring the vertical profiles of the aerosol backscatter and extinction coefficients. Here we present a method for CALIPSO evaluation from combining lidar and in-situ airborne measurements. The limitations of the method have to do mainly with the in-situ instrumentation capabilities and the hydration modelling. We also discuss the future implementation of our method in the ICE-D campaign (Cape Verde, August 2015).

  19. Use of In Situ Cloud Condensation Nuclei, Extinction, and Aerosol Size Distribution Measurements to Test a Method for Retrieving Cloud Condensation Nuclei Profiles From Surface Measurements

    NASA Technical Reports Server (NTRS)

    Ghan, Stephen J.; Rissman, Tracey A.; Ellman, Robert; Ferrare, Richard A.; Turner, David; Flynn, Connor; Wang, Jian; Ogren, John; Hudson, James; Jonsson, Haflidi H.; VanReken, Timothy; Flagan, Richard C.; Seinfeld, John H.

    2006-01-01

    If the aerosol composition and size distribution below cloud are uniform, the vertical profile of cloud condensation nuclei (CCN) concentration can be retrieved entirely from surface measurements of CCN concentration and particle humidification function and surface-based retrievals of relative humidity and aerosol extinction or backscatter. This provides the potential for long-term measurements of CCN concentrations near cloud base. We have used a combination of aircraft, surface in situ, and surface remote sensing measurements to test various aspects of the retrieval scheme. Our analysis leads us to the following conclusions. The retrieval works better for supersaturations of 0.1% than for 1% because CCN concentrations at 0.1% are controlled by the same particles that control extinction and backscatter. If in situ measurements of extinction are used, the retrieval explains a majority of the CCN variance at high supersaturation for at least two and perhaps five of the eight flights examined. The retrieval of the vertical profile of the humidification factor is not the major limitation of the CCN retrieval scheme. Vertical structure in the aerosol size distribution and composition is the dominant source of error in the CCN retrieval, but this vertical structure is difficult to measure from remote sensing at visible wavelengths.

  20. Aircraft

    DTIC Science & Technology

    2002-01-01

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

  1. In-situ measurement of the electrical conductivity of aluminum oxide in HFIR

    SciTech Connect

    Zinkle, S.J.; White, D.P.; Snead, L.L.

    1996-10-01

    A collaborative DOE/Monbusho irradiation experiment has been completed which measured the in-situ electrical resistivity of 12 different grades of aluminum oxide during HFIR neutron irradiation at 450{degrees}C. No evidence for bulk RIED was observed following irradiation to a maximum dose of 3 dpa with an applied dc electric field of 200 V/mm.

  2. IN SITU APPARENT CONDUCTIVITY MEASUREMENTS AND MICROBIAL POPULATION DISTRIBUTION AT A HYDROCARBON CONTAMINATED SITE

    EPA Science Inventory

    We investigated the bulk electrical conductivity and microbial population distribution in sediments at a site contaminated with light non-aqueous phase liquid (LNAPL). The bulk conductivity was measured using in situ vertical resistivity probes, while the most probable number met...

  3. MEASURING VERTICAL PROFILES OF HYDRAULIC CONDUCTIVITY WITH IN SITU DIRECT-PUSH METHODS

    EPA Science Inventory

    U.S. EPA (Environmental Protection Agency) staff developed a field procedure to measure hydraulic conductivity using a direct-push system to obtain vertical profiles of hydraulic conductivity. Vertical profiles were obtained using an in situ field device-composed of a
    Geopr...

  4. Molecular recognition in gas sensing: Results from acoustic wave and in-situ FTIR measurements

    SciTech Connect

    Hierlemann, A.; Ricco, A.J.; Bodenhoefer, K.; Goepel, W.

    1998-06-01

    Surface acoustic wave (SAW) measurements were combined with direct, in-situ molecular spectroscopy to understand the interactions of surface-confined sensing films with gas-phase analytes. This was accomplished by collecting Fourier-transform infrared external-reflectance spectra (FTIR-ERS) on operating SAW devices during dosing of their specifically coated surfaces with key analytes.

  5. In situ technique for measuring heat transfer from a power transistor to a boiling liquid

    NASA Astrophysics Data System (ADS)

    Struble, C. L.; Witte, L. C.

    1994-05-01

    A technique for in situ measurement of temperature and heat flux in boiling heat transfer from electronic chips is described. The method was used to obtain accurate partial boiling curves for jet impingement and pool boiling in R-113. While the characteristics of the heat transfer behavior agree with previous data, the data in general lie below data obtained with specialized test chips.

  6. Comparisons of soil moisture data from in situ measurements and global hydrological model outputs

    NASA Astrophysics Data System (ADS)

    Ramillien, G.; Cazenave, A.; Milly, C.; Robock, A.

    2003-04-01

    In the context of the calibration of the GRACE geodetic mission, we investigated the accuracy of soil moisture variations predicted by a hydrological model. For this purpose, we compare outputs of the global hydrological LaD model with in situ measurements of soil moisture. In situ soil moisture measurements are available from the global moisture data bank (http://climate.envsci.rutgers.edu). The soil moisture values are interpolated in different regions of Eurasia (China, Mongolia, India, Russia) and in the United States, and for periods of several decades. To perform the observations-model comparisons, we interpolated the 1-degree gridded Land Dynamics hydrological model outputs at the locations of the in situ stations. We computed local and regional rms differences and their cross-coherency versus time and space for hundreds of station locations. In general, the model tends to under-estimate the absolute water storage in the soil, and provides smoother values than in situ measurements. However, in terms of temporal variations, both monthly model outputs and direct observations remain highly consistent, especially for the average seasonal cycle.

  7. Chemical ionization tandem mass spectrometer for the in situ measurement of methyl hydrogen peroxide

    SciTech Connect

    St Clair, Jason M.; McCabe, David C.; Crounse, John D.; Steiner, Urs; Wennberg, Paul O.

    2010-09-15

    A new approach for measuring gas-phase methyl hydrogen peroxide [(MHP) CH{sub 3}OOH] utilizing chemical ionization mass spectrometry is presented. Tandem mass spectrometry is used to avoid mass interferences that hindered previous attempts to measure atmospheric CH{sub 3}OOH with CF{sub 3}O{sup -} clustering chemistry. CH{sub 3}OOH has been successfully measured in situ using this technique during both airborne and ground-based campaigns. The accuracy and precision for the MHP measurement are a function of water vapor mixing ratio. Typical precision at 500 pptv MHP and 100 ppmv H{sub 2}O is {+-}80 pptv (2 sigma) for a 1 s integration period. The accuracy at 100 ppmv H{sub 2}O is estimated to be better than {+-}40%. Chemical ionization tandem mass spectrometry shows considerable promise for the determination of in situ atmospheric trace gas mixing ratios where isobaric compounds or mass interferences impede accurate measurements.

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

    NASA Astrophysics Data System (ADS)

    Schulte, P.; Schlager, H.

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

  9. Aircraft-borne, laser-induced fluorescence instrument for the in situ detection of hydroxyl and hydroperoxyl radicals

    NASA Technical Reports Server (NTRS)

    Wennberg, P. O.; Cohen, R. C.; Hazen, N. L.; Lapson, L. B.; Allen, N. T.; Hanisco, T. F.; Oliver, J. F.; Lanham, N. W.; Demusz, J. N.; Anderson, J. G.

    1994-01-01

    The odd-hydrogen radicals OH and HO2 are central to most of the gas-phase chemical transformations that occur in the atmosphere. Of particular interest is the role that these species play in controlling the concentration of stratospheric ozone. This paper describes an instrument that measures both of these species at volume mixing ratios below one part in 10(exp 14) in the upper troposphere and lower stratosphere. The hydroxyl radical (OH) is measured by laser induced fluorescence at 309 nm. Tunable UV light is used to pump OH to the first electric state near 282 nm. the laser light is produced by a high-repetition rate pulsed dye-laser powered with all solid-state pump lasers. HO2 is measured as OH after gas-phase titration with nitric oxide. Measurements aboard a NASA ER-2 aircraft demonstrate the capability of this instrument to perform reliably with very high signal-to-noise ratios (greater than 30) achieved in short integration times (less than 20 sec).

  10. Initial in Situ Measurements of Perennial Meltwater Storage in the Greenland Firn Aquifer

    NASA Technical Reports Server (NTRS)

    Koenig, Lora S.; Miege, Clement; Forster, Richard R.; Brucker, Ludovic

    2014-01-01

    A perennial storage of water in a firn aquifer was discovered in southeast Greenland in 2011. We present the first in situ measurements of the aquifer, including densities and temperatures. Water was present at depths between approx. 12 and 37m and amounted to 18.7 +/- 0.9 kg in the extracted core. The water filled the firn to capacity at approx. 35m. Measurements show the aquifer temperature remained at the melting point, representing a large heat reservoir within the firn. Using model results of liquid water extent and aquifer surface depth from radar measurements, we extend our in situ measurements to the Greenland ice sheet. The estimated water volume is 140 +/- 20 Gt, representing approx. 0.4mm of sea level rise (SLR). It is unknown if the aquifer temporary buffers SLR or contributes to SLR through drainage and/or ice dynamics.

  11. Initial in situ measurements of perennial meltwater storage in the Greenland firn aquifer

    NASA Astrophysics Data System (ADS)

    Koenig, Lora S.; Miège, Clément; Forster, Richard R.; Brucker, Ludovic

    2014-01-01

    perennial storage of water in a firn aquifer was discovered in southeast Greenland in 2011. We present the first in situ measurements of the aquifer, including densities and temperatures. Water was present at depths between ~12 and 37 m and amounted to 18.7 ± 0.9 kg in the extracted core. The water filled the firn to capacity at ~35 m. Measurements show the aquifer temperature remained at the melting point, representing a large heat reservoir within the firn. Using model results of liquid water extent and aquifer surface depth from radar measurements, we extend our in situ measurements to the Greenland ice sheet. The estimated water volume is 140 ± 20 Gt, representing ~0.4 mm of sea level rise (SLR). It is unknown if the aquifer temporary buffers SLR or contributes to SLR through drainage and/or ice dynamics.

  12. Using in situ airborne measurements to evaluate three cloud phase products derived from CALIPSO

    NASA Astrophysics Data System (ADS)

    Cesana, G.; Chepfer, H.; Winker, D.; Getzewich, B.; Cai, X.; Jourdan, O.; Mioche, G.; Okamoto, H.; Hagihara, Y.; Noel, V.; Reverdy, M.

    2016-05-01

    We compare the cloud detection and cloud phase determination of three independent climatologies based on Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) to airborne in situ measurements. Our analysis of the cloud detection shows that the differences between the satellite and in situ measurements mainly arise from three factors. First, averaging CALIPSO Level l data along track before cloud detection increases the estimate of high- and low-level cloud fractions. Second, the vertical averaging of Level 1 data before cloud detection tends to artificially increase the cloud vertical extent. Third, the differences in classification of fully attenuated pixels among the CALIPSO climatologies lead to differences in the low-level Arctic cloud fractions. In another section, we compare the cloudy pixels detected by colocated in situ and satellite observations to study the cloud phase determination. At midlatitudes, retrievals of homogeneous high ice clouds by CALIPSO data sets are very robust (more than 94.6% of agreement with in situ). In the Arctic, where the cloud phase vertical variability is larger within a 480 m pixel, all climatologies show disagreements with the in situ measurements and CALIPSO-General Circulation Models-Oriented Cloud Product (GOCCP) report significant undefined-phase clouds, which likely correspond to mixed-phase clouds. In all CALIPSO products, the phase determination is dominated by the cloud top phase. Finally, we use global statistics to demonstrate that main differences between the CALIPSO cloud phase products stem from the cloud detection (horizontal averaging, fully attenuated pixels) rather than the cloud phase determination procedures.

  13. A battery cell for in situ NMR measurements of liquid electrolytes.

    PubMed

    Wiemers-Meyer, Simon; Winter, Martin; Nowak, Sascha

    2017-02-15

    This work describes the development of an in situ battery cell to monitor liquid electrolytes by means of NMR spectroscopy. The suitability of this approach is confirmed by NMR measurements and electrochemical analysis. The cell allows for undistorted high resolution NMR spectroscopy. Furthermore, constant current cycling data, C-rate sequences and impedance measurements indicates a long cycle life as well as reasonable specific capacities and Ohmic resistances.

  14. Digital Holography for in Situ Real-Time Measurement of Plasma-Facing-Component Erosion

    SciTech Connect

    ThomasJr., C. E.; Granstedt, E. M.; Biewer, Theodore M; Baylor, Larry R; Combs, Stephen Kirk; Meitner, Steven J; Hillis, Donald Lee; Majeski, R.; Kaita, R.

    2014-01-01

    In situ, real time measurement of net plasma-facing-component (PFC) erosion/deposition in a real plasma device is challenging due to the need for good spatial and temporal resolution, sufficient sensitivity, and immunity to fringe-jump errors. Design of a high-sensitivity, potentially high-speed, dual-wavelength CO2 laser digital holography system (nominally immune to fringe jumps) for PFC erosion measurement is discussed.

  15. Inferring water vapor amounts with solar spectral irradiance: Measurements, modeling, and comparisons with in situ water vapor profiles in the upper troposphere lower stratosphere from ATTREX

    NASA Astrophysics Data System (ADS)

    Kindel, B. C.; Pilewskie, P.; Schmidt, S.; Thornberry, T. D.; Rollins, D. W.; LeBlanc, S. E.; Bui, T. V.

    2013-12-01

    The Airborne Tropical TRopopause Experiment (ATTREX) flew six science missions on the NASA Global Hawk aircraft from NASA Dryden, California to the Pacific tropics to sample the upper troposphere, lower stratosphere (UTLS) during February and March of 2013. After transit to the tropics, the aircraft performed a series of vertical profiles from the cruising altitude of about 18 km down to 14 km sampling the tropical tropopause layer (TTL). A science focus of ATTREX is to examine water vapor and its transport through the TTL. The extremely cold temperatures found in the TTL act to limit the transport of water vapor from the troposphere to stratosphere, making this region critical to the water vapor budget of the stratosphere. Here we investigate the use of the strong water bands centered at 1400 and 1900 nm in the telluric solar spectrum to infer the small water vapor amounts through the TTL. Measurements of spectral irradiance from the Solar Spectral Flux Radiometer (SSFR) at the top and bottom of the aircraft profiles are used to produce transmission spectra. These are compared with atmospheric radiative transfer calculations of transmission through the layer. The measured water vapor profile from the NOAA water vapor instrument, as well as temperature and pressure, were used in the modeling, providing a rare opportunity to compare water vapor amount inferred from solar transmittance to in situ measurements. Prospects for the use of these bands for determining the total column water vapor amount from the UTLS to the top of the atmosphere from aircraft are also discussed.

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

    NASA Astrophysics Data System (ADS)

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

    2003-10-01

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

  17. Estimates of total organic and inorganic chlorine in the lower stratosphere from in situ and flask measurements during AASE 2

    NASA Technical Reports Server (NTRS)

    Woodbridge, E. L.; Elkins, J. W.; Fahey, D. W.; Heidt, L. E.; Solomon, S.; Baring, T. J.; Gilpin, T. M.; Pollack, W. H.; Schauffler, S. M.; Atlas, E. L.

    1995-01-01

    Aircraft sampling has provided extensive in situ and flask measurements of organic chlorine species in the lower stratosphere. The recent Airborne Arctic Stratospheric Expedition 2 (AASE 2) included two independent measurements of organic chlorine species using whole air sample and real-time techniques. From the whole air sample measurements we derive directly the burden of total organic chlorine (CCl(y)) in the lower stratosphere. From the more limited real-time measurements we estimate the CCl(y) burden using mixing ratios and growth rates of the principal CCl(y) species in the troposphere in conjunction with results from a two-dimensional photochemical model. Since stratospheric chlorine is tropospheric in origin and tropospheric mixing ratios are increasing, it is necessary to establish the average age of a stratospheric air parcel to assess its total chlorine (Cl(sub Total)) abundance. Total inorganic chlorine (Cl(y)) in the parcel is then estimated by the simple difference, Cl(y) = Cl(sub Total) - CCl(y). The consistency of the results from these two quite different techniques suggests that we can determine the CCl(y) and Cl(y) in the lower stratosphere with confidence. Such estimates of organic and inorganic chlorine are crucial in evaluating the photochemistry controlling chlorine partitioning and hence ozone loss processes in the lower stratosphere.

  18. Estimates of total organic and inorganic chlorine in the lower stratosphere from in situ and flask measurements during AASE 2

    SciTech Connect

    Woodbridge, E.L.; Elkins, J.W.; Fahey, D.W.; Heidt, L.E.; Solomon, S.; Baring, T.J.; Gilpin, T.M.; Pollack, W.H.; Schauffler, S.M.; Atlas, E.L. ||

    1995-02-01

    Aircraft sampling has provided extensive in situ and flask measurements of organic chlorine species in the lower stratosphere. The recent Airborne Arctic Stratospheric Expedition 2 (AASE 2) included two independent measurements of organic chlorine species using whole air sample and real-time techniques. From the whole air sample measurements we derive directly the burden of total organic chlorine (CCl(y)) in the lower stratosphere. From the more limited real-time measurements we estimate the CCl(y) burden using mixing ratios and growth rates of the principal CCl(y) species in the troposphere in conjunction with results from a two-dimensional photochemical model. Since stratospheric chlorine is tropospheric in origin and tropospheric mixing ratios are increasing, it is necessary to establish the average age of a stratospheric air parcel to assess its total chlorine (Cl(sub Total)) abundance. Total inorganic chlorine (Cl(y)) in the parcel is then estimated by the simple difference, Cl(y) = Cl(sub Total) - CCl(y). The consistency of the results from these two quite different techniques suggests that we can determine the CCl(y) and Cl(y) in the lower stratosphere with confidence. Such estimates of organic and inorganic chlorine are crucial in evaluating the photochemistry controlling chlorine partitioning and hence ozone loss processes in the lower stratosphere.

  19. Measurements of Absorbing Aerosols Using in Situ and Remote Sensing Techniques

    NASA Astrophysics Data System (ADS)

    Martins, J. V.; Martins, J. V.; Kaufman, Y.; Artaxo, P.; Andrea, C.; Yamasoe, M.; Remer, L.

    2001-12-01

    Reliable measurements of light absorption by aerosol particles are essential for an accurate assessment of the climate radiative forcing by aerosol particles. Depending on the absorption properties, the radiative forcing of the aerosols may change from a cooling to a heating effect. New techniques for the remote sensing of aerosol absorption over land and ocean are developed and applied in combination with in situ measurements for validation and addition of complementary information. Spectral measurements show the effects of aerosols on absorption of light from the UV to the near infrared. Depending on particle size and structure, there is a significant absorption component that must be accounted for the radiative forcing in the near infrared. Remote sensing results from MODIS and from the CLAMS field experiment, as well as in situ validation data will be discussed.

  20. In Situ Field Measurement of Leaf Water Potential Using Thermocouple Psychrometers 1

    PubMed Central

    Savage, Michael J.; Wiebe, Herman H.; Cass, Alfred

    1983-01-01

    Thermocouple psychrometers are the only instruments which can measure the in situ water potential of intact leaves, and which can possibly be used to monitor leaf water potential. Unfortunately, their usefulness is limited by a number of difficulties, among them fluctuating temperatures and temperature gradients within the psychrometer, sealing of the psychrometer chamber to the leaf, shading of the leaf by the psychrometer, and resistance to water vapor diffusion by the cuticle when the stomates are closed. Using Citrus jambhiri, we have tested several psychrometer design and operational modifications and showed that in situ psychrometric measurements compared favorably with simultaneous Scholander pressure chamber measurements on neighboring leaves when the latter were corrected for the osmotic potential. PMID:16663267

  1. Validation of Satellite Observed Soil Moisture Using In-Situ Measurements

    NASA Astrophysics Data System (ADS)

    van der Velde, Rogier; Yu, Xiaolong; Zheng, Donghai; Benninga, Harm-Jan F.; Shahmohamadi, Mohamad Ali; Hendriks, Dimmie; Hunnink, Joachim; Coliander, Andreas; Jackson, Thomas J.; Bindlish, Rajat; Chan, Steven K.; Su, Bob

    2016-08-01

    Although with in-situ techniques soil moisture can be measured reliably at point-scale, it remains a challengeto translate a collection of point measurements tothe scale of satellite footprints (> 10 km). Spatially distributed soil moisture simulations by the Dutch Landelijk Hydro-logisch Model (LHM, De Lange et al. 2014) are here employed for this task. The upscaled in- situ measurements are subsequently utilized to assess the CATDS (Centre Aval de Traitement des Données SMOS, Soil Moisture and Ocean Salinity, Jacquette et al. 2010) L3 and the NASA SMAP (Soil Moisture Active Passive)L2 radiometer-only soil moisture products (O'Neill et al. 2015).

  2. Combining Space-Based and In-Situ Measurements to Track Flooding in Thailand

    NASA Technical Reports Server (NTRS)

    Chien, Steve; Doubleday, Joshua; Mclaren, David; Tran, Daniel; Tanpipat, Veerachai; Chitradon, Royal; Boonya-aaroonnet, Surajate; Thanapakpawin, Porranee; Khunboa, Chatchai; Leelapatra, Watis; Plermkamon, Vichian; Raghavendra, Cauligi; Mandl, Daniel

    2011-01-01

    We describe efforts to integrate in-situ sensing, space-borne sensing, hydrological modeling, active control of sensing, and automatic data product generation to enhance monitoring and management of flooding. In our approach, broad coverage sensors and missions such as MODIS, TRMM, and weather satellite information and in-situ weather and river gauging information are all inputs to track flooding via river basin and sub-basin hydrological models. While these inputs can provide significant information as to the major flooding, targetable space measurements can provide better spatial resolution measurements of flooding extent. In order to leverage such assets we automatically task observations in response to automated analysis indications of major flooding. These new measurements are automatically processed and assimilated with the other flooding data. We describe our ongoing efforts to deploy this system to track major flooding events in Thailand.

  3. Comparison of MTI Satellite-Derived Surface Water Temperatures and In-Situ Measurements

    SciTech Connect

    Kurzeja, R.

    2001-07-26

    Temperatures of the water surface of a cold, mid-latitude lake and the tropical Pacific Ocean were determined from MTI images and from in situ concurrent measurements. In situ measurements were obtained at the time of the MTI image with a floating, anchored platform, which measured the surface and bulk water temperatures and relevant meteorological variables, and also from a boat moving across the target area. Atmospheric profiles were obtained from concurrent radiosonde soundings. Radiances at the satellite were calculated with the Modtran radiative transfer model. The MTI infrared radiances were within 1 percent of the calculated values at the Pacific Ocean site but were 1-2 percent different over the mid-latitude lake.

  4. Orthoclase surface structure dissolution measured in situ by x-ray reflectivity and atomic force microscopy.

    SciTech Connect

    Sturchio, N. C.; Fenter, P.; Cheng, L.; Teng, H.

    2000-11-28

    Orthoclase (001) surface topography and interface structure were measured during dissolution by using in situ atomic force microscopy (AFM) and synchrotrons X-ray reflectivity at pH 1.1-12.9 and T = 25-84 C. Terrace roughening at low pH and step motion at high pH were the main phenomena observed, and dissolution rates were measured precisely. Contrasting dissolution mechanisms are inferred for low- and high-pH conditions. These observations clarify differences in alkali feldspar dissolution mechanisms as a function of pH, demonstrate a new in situ method for measuring face-specific dissolution rates on single crystals, and improve the fundamental basis for understanding alkali feldspar weathering processes.

  5. In situ autonomous optical radiometry measurements for satellite ocean color validation in the Western Black Sea

    NASA Astrophysics Data System (ADS)

    Zibordi, G.; Mélin, F.; Berthon, J.-F.; Talone, M.

    2015-03-01

    The accuracy of primary satellite ocean color data products from the Moderate Resolution Imaging Spectroradiometer on-board Aqua (MODIS-A) and the Visible/Infrared Imager/Radiometer Suite (VIIRS) is investigated in the Western Black Sea using in situ measurements from the Gloria site included in the ocean color component of the Aerosol Robotic Network (AERONET-OC). The analysis is also extended to an additional well-established AERONET-OC site in the northern Adriatic Sea characterized by optically complex coastal waters exhibiting similarities to those observed at the Gloria site. Results from the comparison of normalized water-leaving radiance LWN indicate biases of a few percent between satellite-derived and in situ data at the center wavelengths relevant for the determination of chlorophyll a concentrations (443-547 nm, or equivalent). Remarkable is the consistency between the annual cycle determined with time series of satellite-derived and in situ LWN ratios at these center wavelengths. Contrarily, the differences between in situ and satellite-derived LWN are pronounced at the blue (i.e., 412 nm) and red (i.e., 667 nm, or equivalent) center wavelengths, confirming difficulties in confidently applying satellite-derived radiometric data from these spectral regions for quantitative analysis in optically complex waters.

  6. Time lapse 3D geoelectric measurements for monitoring of in-situ remediation

    NASA Astrophysics Data System (ADS)

    Tildy, Péter; Neducza, Boriszláv; Nagy, Péter; Kanli, Ali Ismet; Hegymegi, Csaba

    2017-01-01

    In the last decade, different kinds of in-situ methods have been increasingly used for hydrocarbon contamination remediation due to their effectiveness. One of these techniques operates by injection of chemical oxidant solution to remove (degrade) the subsurface contaminants. Our aim was to develop a surface (non-destructive) measurement strategy to monitor oxidative in-situ remediation processes. The difficulties of the presented study originate from the small volume of conductive solution that can be used due to environmental considerations, the effect of conductive groundwater and the high clay content of the targeted layer. Therefore a site specific synthetic modelling was necessary for measurement design involving the results of preliminary 2D ERT measurements, electrical conductivity measurements of different active agents and expected resistivity changes calculated by soil resistivity modelling. The results of soil resistivity modelling have suggested that the reagent have complex effects on contaminated soils because of chemical biodegradation. As a result the plume of resistivity changes caused by the injected agent was determined showing strong fracturing effect because of the high pressure of injection. Based on the sophisticated tests and synthetic modelling 3D time-lapse geo-electric measurements were proven to provide a usable monitoring tool for in-situ remediation to help in-field design of such techniques.

  7. Deriving an atmospheric budget of total organic bromine using airborne in-situ measurements from the Western Pacific during SHIVA

    NASA Astrophysics Data System (ADS)

    Sala, S.; Bönisch, H.; Keber, T.; Oram, D. E.; Mills, G.; Engel, A.

    2014-02-01

    During the SHIVA (Stratospheric Ozone: Halogen Impacts in a Varying Atmosphere) project an extensive dataset of all halogen species relevant for the atmospheric budget of total organic bromine has been collected in the West Pacific region using the FALCON aircraft operated by the German Aerospace agency DLR (Deutsches Zentrum für Luft- und Raumfahrt) covering a vertical range from the planetary boundary layer up to the ceiling altitude of the aircraft of 13 km. In total, more than 700 measurements were performed with the newly developed fully-automated in-situ instrument GHOST-MS (Gas cHromatograph for the Observation of Tracers - coupled with a Mass Spectrometer) by the Goethe University of Frankfurt (GUF) and with the onboard whole-air sampler WASP with subsequent ground based state-of-the-art GC/MS analysis by the University of East Anglia (UEA). Both instruments yield good agreement for all major (CHBr3 and CH2Br2) and minor (CHBrCl, CHBrCl2 and CHBr2Cl) VSLS (very short-lived substances), at least at the level of their 2 σ measurement uncertainties. In contrast to the suggestion that the Western Pacific could be a major source region for VSLS (Pyle et al., 2011), we found only slightly enhanced mixing ratios of brominated halogen source gases relative to the levels reported in Montzka et al. (2011) for other tropical regions. A budget for total organic bromine, including all four halons,CH3Br and the VSLS, is derived for the upper troposphere, the input region for the TTL and thus also for the stratosphere, compiled from the SHIVA dataset. With exception of the two minor VSLS CHBrCl2 and CHBr2Cl, excellent agreement with the values reported in Montzka et al. (2011) is found, while being slightly higher than previous studies from our group based on balloon-borne measurements.

  8. Evidence for ice particles in the tropical stratosphere from in-situ measurements

    NASA Astrophysics Data System (ADS)

    de Reus, M.; Borrmann, S.; Bansemer, A.; Heymsfield, A. J.; Weigel, R.; Schiller, C.; Mitev, V.; Frey, W.; Kunkel, D.; Kürten, A.; Curtius, J.; Sitnikov, N. M.; Ulanovsky, A.; Ravegnani, F.

    2009-09-01

    In-situ ice crystal size distribution measurements are presented within the tropical troposphere and lower stratosphere. The measurements were performed using a combination of a Forward Scattering Spectrometer Probe (FSSP-100) and a Cloud Imaging Probe (CIP), which were installed on the Russian high altitude research aircraft M55 "Geophysica" during the SCOUT-O3 campaign in Darwin, Australia. One of the objectives of the campaign was to characterise the Hector convective system, which appears on an almost daily basis during the pre-monsoon season over the Tiwi Islands, north of Darwin. In total 90 encounters with ice clouds, between 10 and 19 km altitude were selected from the dataset and were analysed. Six of these encounters were observed in the lower stratosphere, up to 1.4 km above the local tropopause. Concurrent lidar measurements on board "Geophysica" indicate that these ice clouds were a result of overshooting convection. Large ice crystals, with a maximum dimension up to 400 μm, were observed in the stratosphere. The stratospheric ice clouds included an ice water content ranging from 7.7×10-5 to 8.5×10-4 g m-3 and were observed at ambient relative humidities (with respect to ice) between 75 and 157%. Three modal lognormal size distributions were fitted to the average size distributions for different potential temperature intervals, showing that the shape of the size distribution of the stratospheric ice clouds are similar to those observed in the upper troposphere. In the tropical troposphere the effective radius of the ice cloud particles decreases from 100 μm at about 10 km altitude, to 3 μm at the tropopause, while the ice water content decreases from 0.04 to 10-5 g m-3. No clear trend in the number concentration was observed with altitude, due to the thin and inhomogeneous characteristics of the observed cirrus clouds. The ice water content calculated from the observed ice crystal size distribution is compared to the ice water content derived from

  9. 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.

  10. 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.

  11. Integrated Airborne and In-Situ Measurements over Land-Fast Ice near Barrow, AK.

    NASA Astrophysics Data System (ADS)

    Brozena, J. M.; Gardner, J. M.; Liang, R.; Ball, D.; Richter-Menge, J.; Claffey, K. J.; Abelev, A.; Hebert, D. A.; Jones, K.

    2014-12-01

    During March of 2014, the Naval Research Laboratory and the Cold Regions Research and Engineering Laboratory collected an integrated set of airborne and in-situ measurements over two areas of floating, but land-fast ice near the coast of Barrow, AK. The near-shore site was just north of Point Barrow, and the "offshore" site was ~ 20 km east of Point Barrow. The in-situ data provided ground-truth for airborne measurements from a scanning LiDAR (Riegl Q 560i), digital photogrammetry (Applanix DSS-439) and a snow radar procured from the Center for Remote Sensing of Ice Sheets of the University of Kansas. The objective of the survey was to aid our understanding of the use of the airborne data to calibrate/validate Cryosat-2 data. Sampling size or "footprint" plays a critical role in the attempt to compare in-situ measurements with airborne (or satellite) measurements. Thus the in-situ data were arranged to minimize aliasing. Ground measurements were collected along transects at both sites consisting of a 2 km long profile of snow depth and ice thickness measurements with periodic boreholes. A 60 m x 400 m swath of snow depth measurements was centered on this profile. Airborne data were collected on five overflights of the two transect areas. The LiDAR measured total freeboard (ice + snow) referenced to leads in the ice, and produced swaths 200-300 m wide. The radar measured snow thickness. The freeboard and snow thickness measurements are used to estimate ice thickness via isostasy and density estimates. The central swath of in situ snow depth data allows examination of the effects of cross-track variations considering the relatively large footprint of the snow radar. Assuming a smooth, flat surface the radar range resolution in air is < 4 cm, but the along-track sampling distance is ~ 3 m after unfocussed SAR processing. The width of the footprint varies from ~ 9 m up to about 40 m (beam-limited) for uneven surfaces. However, the radar could not resolve snow thickness

  12. 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.

  13. Aerial and in situ Measurements of Submesoscale Eddies, Fronts, and Filaments

    NASA Astrophysics Data System (ADS)

    Baschek, Burkard; Maarten Molemaker, Jeroen

    2010-05-01

    Submesoscale eddies, fronts, and filaments on scales of 10 m to 20 km are common features of many coastal regions of the world. Modeling results suggest that these submesoscale phenomena play an important role in local energy cascades, transferring energy from the large-scale ocean circulation to turbulence. It is also likely that submesoscale features are important for mixing, vertical transport, or biogeochemical processes. While submesoscale features have been observed using SAR satellite imagery, only very limited in situ measurements exist that reveal the dynamically relevant internal structure. Submesoscale features have a life time of several hours to a few days and advective speeds of up to 0.5 ms-1, which makes it very hard to measure them with traditional in situ sampling. Also satellite sea surface temperature (SST) data cannot sufficiently resolve the small scales of these features. We present aerial and in situ measurements of submesoscale eddies, fronts, and filaments, and believe to have carried out the first time in situ measurements of a spiral eddy (~2.5 km diameter) during a 5-day experiment in September 2009 off Catalina Island, CA. The observations are taken with a cost efficient and pragmatic observational approach for repeat quasi-synoptic measurements of submesoscale features in real-time and on the required small spatial and temporal scales of ~30min and ~20m. An IR camera mounted on a small plane is used to derive fine-resolution SST maps of this area and to guide a fast response vessel to distinct submesoscale features. A temperature/pressure array is towed in the upper 45m at speeds of 5 ms-1 through the features. The properties of the submesoscale features are examined within the context of the larger-scale circulation patterns of this highly variable coastal region combined with the analysis of satellite SST, coastal radar, and mooring data.

  14. Micro weather stations for in situ measurements in the Martian planetary boundary layer

    NASA Technical Reports Server (NTRS)

    Crisp, D.; Kaiser, W. J.; Kenny, T. W.; Vanzandt, T. R.; Tillman, J. E.

    1992-01-01

    Viking Lander meteorology measurements show that the Martian planetary boundary layer (PBL) has large diurnal and seasonal variations in pressure, wind velocity, relative humidity, and airborne dust loading. An even larger range of conditions was inferred from remote sensing observations acquired by the Mariner 9 and Viking orbiters. Numerical models indicate that these changes may be accompanied by dramatic vertical and horizontal wind shears (100 m/s/km) and rapid changes in the static stability. In-situ measurements from a relatively small number surface stations could yield global constraints on the Martian climate and atmospheric general circulation by providing ground truth for remote sensing instruments on orbiters. A more complete understanding of the meteorology of the PBL is an essential precursor to manned missions to Mars because this will be their working environment. In-situ measurements are needed for these studies because the spatial and temporal scales that characterize the important meteorological processes near the surface cannot be resolved from orbit. The Mars Environmental Survey (MESUR) Program will provide the first opportunity to deploy a network of surface weather stations for a comprehensive investigation of the Martian PBL. The feasibility and utility of a network of micro-weather stations for making in-situ meteorological measurements in the Martian PBL are assessed.

  15. Intercomparison of MODIS Albedo Retrievals and In Situ Measurements Across the Global FLUXNET Network

    NASA Technical Reports Server (NTRS)

    Cescatti, Alessandro; Marcolla, Barbara; Vannan, Suresh K. Santhana; Pan, Jerry Yun; Roman, Miguel O.; Yang, Xiaoyuan; Ciais, Philippe; Cook, Robert B.; Law, Beverly E.; Matteucci, Girogio; Migliavacca, Mirco; Moors, Eddy; Richardson, Andrew D.; Seufert, Guenther; Schaaf, Crystal B.

    2012-01-01

    Surface albedo is a key parameter in the Earth's energy balance since it affects the amount of solar radiation directly absorbed at the planet surface. Its variability in time and space can be globally retrieved through the use of remote sensing products. To evaluate and improve the quality of satellite retrievals, careful intercomparisons with in situ measurements of surface albedo are crucial. For this purpose we compared MODIS albedo retrievals with surface measurements taken at 53 FLUXNET sites that met strict conditions of land cover homogeneity. A good agreement between mean yearly values of satellite retrievals and in situ measurements was found (R(exp 2)= 0.82). The mismatch is correlated to the spatial heterogeneity of surface albedo, stressing the relevance of land cover homogeneity when comparing point to pixel data. When the seasonal patterns of MODIS albedo is considered for different plant functional types, the match with surface observation is extremely good at all forest sites. On the contrary, in non-forest sites satellite retrievals underestimate in situ measurements across the seasonal cycle. The mismatch observed at grasslands and croplands sites is likely due to the extreme fragmentation of these landscapes, as confirmed by geostatistical attributes derived from high resolution scenes.

  16. Aircraft body-axis rotation measurement system

    NASA Technical Reports Server (NTRS)

    Cowdin, K. T. (Inventor)

    1983-01-01

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

  17. In situ azimuthal rotation device for linear dichroism measurements in scanning transmission x-ray microscopy

    NASA Astrophysics Data System (ADS)

    Hernández-Cruz, D.; Hitchcock, A. P.; Tyliszczak, T.; Rousseau, M.-E.; Pézolet, M.

    2007-03-01

    A novel miniature rotation device used in conjunction with a scanning transmission x-ray microscope is described. It provides convenient in situ sample rotation to enable measurements of linear dichroism at high spatial resolution. The design, fabrication, and mechanical characterization are presented. This device has been used to generate quantitative maps of the spatial distribution of the orientation of proteins in several different spider and silkworm silks. Specifically, quantitative maps of the dichroic signal at the C 1s→π*amide transition in longitudinal sections of the silk fibers give information about the spatial orientation, degree of alignment, and spatial distribution of protein peptide bonds. A new approach for analyzing the dichroic signal to extract orientation distributions, in addition to magnitudes of aligned components, is presented and illustrated with results from Nephila clavipes dragline spider silk measured using the in situ rotation device.

  18. Chemical isolation of quartz for measurement of in-situ-produced cosmogenic nuclides

    NASA Technical Reports Server (NTRS)

    Kohl, C. P.; Nishiizumi, K.

    1992-01-01

    An isolation method relying totally on chemical steps was developed to separate large quantities (10-200 g) of clean mono-minerallic quartz samples from a variety of terrestrial rocks and soils for the purpose of measuring Be-10 (t1/2 = 1.5 Myr) and Al-26 (t1/2 = 0.705 Myr) produced by cosmic rays in situ in the quartz phase. The procedure consists of grinding the sample, heating it in HCl, and treating it with a series of leaches using a dilute HF/HNO3 mixture in a heated ultrasonic tank. The purified quartz was also used for the measurements of in situ cosmic-ray-produced Ne-21 and C-14 (t1/2 = 5730 yr). The method is applicable to any problem requiring purified quartz on a large scale.

  19. Spatially resolved, in situ potential measurements through porous electrodes as applied to fuel cells.

    PubMed

    Hess, Katherine C; Epting, William K; Litster, Shawn

    2011-12-15

    We report the development and use of a microstructured electrode scaffold (MES) to make spatially resolved, in situ, electrolyte potential measurements through the thickness of a polymer electrolyte fuel cell (PEFC) electrode. This new approach uses a microfabricated apparatus to analyze the coupled transport and electrochemical phenomena in porous electrodes at the microscale. In this study, the MES allows the fuel cell to run under near-standard operating conditions, while providing electrolyte potential measurements at discrete distances through the electrode's thickness. Here we use spatial distributions of electrolyte potential to evaluate the effects of Ohmic and mass transport resistances on the through-plane reaction distribution for various operating conditions. Additionally, we use the potential distributions to estimate the ionic conductivity of the electrode. Our results indicate the in situ conductivity is higher than typically estimated for PEFC electrodes based on bulk polymer electrolyte membrane (PEM) conductivity.

  20. Stresses in Copper Damascene Lines: In-situ Measurements and Finite Element Analysis

    SciTech Connect

    Gergaud, P.; Baldacci, A.; Thomas, O.; Rivero, C.; Sicardy, O.; Micha, J.-S.

    2006-02-07

    The mechanical properties of thin damascene Cu lines are investigated by in-situ x-ray diffraction, in-situ curvature measurements and finite element calculations. At variance with the behavior of blanket films, 0.3 {mu}m lines exhibit a thermo-elastic behavior which is well reproduced by finite element calculations. The curvature measurements confirm this pure elastic behavior. The triaxial stress state in the lines may explain the lack of plasticity at reduced temperatures because different stress tensor element make the resolved stress cancel out. Profile analysis of the X-ray peaks are compared to the strain distribution deduced from the finite element calculations. The good agreement confirms the large strain inhomogeneities in the lines due to interfacial effects.

  1. Comfort improvement of a nonlinear suspension using global optimization and in situ measurements

    NASA Astrophysics Data System (ADS)

    Deprez, K.; Moshou, D.; Ramon, H.

    2005-06-01

    The health problems encountered by operators of off-road vehicles demonstrate that a lot of effort still has to be put into the design of effective seat and cabin suspensions. Owing to the nonlinear nature of the suspensions and the use of in situ measurements for the optimization, classical local optimization techniques are prone to getting stuck in local minima. Therefore this paper develops a method for optimizing nonlinear suspension systems based on in situ measurements, using the global optimization technique DIRECT to avoid local minima. Evaluation of the comfort improvement of the suspension was carried out using the objective comfort parameters used in standards. As a test case, the optimization of a hydropneumatic element that can serve as part of a cabin suspension for off-road machinery was performed.

  2. 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.

  3. Apparatus for in-situ calibration of instruments that measure fluid depth

    DOEpatents

    Campbell, Melvin D.

    1994-01-01

    The present invention provides a method and apparatus for in-situ calibration of distance measuring equipment. The method comprises obtaining a first distance measurement in a first location, then obtaining at least one other distance measurement in at least one other location of a precisely known distance from the first location, and calculating a calibration constant. The method is applied specifically to calculating a calibration constant for obtaining fluid level and embodied in an apparatus using a pressure transducer and a spacer of precisely known length. The calibration constant is used to calculate the depth of a fluid from subsequent single pressure measurements at any submerged position.

  4. Apparatus for in-situ calibration of instruments that measure fluid depth

    DOEpatents

    Campbell, M.D.

    1994-01-11

    The present invention provides a method and apparatus for in-situ calibration of distance measuring equipment. The method comprises obtaining a first distance measurement in a first location, then obtaining at least one other distance measurement in at least one other location of a precisely known distance from the first location, and calculating a calibration constant. The method is applied specifically to calculating a calibration constant for obtaining fluid level and embodied in an apparatus using a pressure transducer and a spacer of precisely known length. The calibration constant is used to calculate the depth of a fluid from subsequent single pressure measurements at any submerged position. 8 figures.

  5. 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.

  6. Development of novel sol-gel indicators (SGI`s) for in-situ environmental measurements

    SciTech Connect

    Livingston, R.R.; Wicks, G.G.; Baylor, L.C.; Whitaker, M.J.

    1993-10-01

    Organic indicator molecules have been incorporated in a porous sol- gel matrix coated on the end of a fiber-optic lens assembly to create sensors for in situ environmental measurements. Probes have been made that are sensitive to pH and uranyl concentration. The use of fiber optics allows the probe to be lowered into a well or bore hole, while support equipment such as a spectrophotometer and computer may be situated hundreds of meters away.

  7. Experimental Development of a Novel Stress Sensor for in situ Stress Measurement

    SciTech Connect

    Polsky, Yarom; Lance, Michael J; Mattus, Catherine H; Daniels, Ryan J

    2016-01-01

    This paper will describe ongoing work to adapt a previously demonstrated method for measuring stress in ceramics to develop a borehole deployed in situ stress sensor. The method involves the use of a cementitious material which exhibits a strong piezo-spectroscopic stress response as a downhole stress gage. A description of the conceptual approach will be provided along with preliminary analysis and proof-of-concept laboratory results.

  8. Airborne, In Situ and Laboratory Measurements of the Optical and Photochemical Properties of Surface Marine Waters

    DTIC Science & Technology

    2016-06-07

    Airborne, In Situ And Laboratory Measurements Of The Optical And Photochemical Properties Of Surface Marine Waters Neil V. Blough Department of...matter (CDOM) in marine and estuarine waters , 2) to determine the impact of CDOM on the aquatic light field and remotely-sensed optical signals, 3) to...October 1999 was performed to examine the optical and photochemical properties of waters in the Middle Atlantic Bight and in the Delaware and Chesapeake

  9. Fast-response airborne in situ measurements of HNO3 during the Texas 2000 Air Quality Study

    NASA Astrophysics Data System (ADS)

    Neuman, J. A.; Huey, L. G.; Dissly, R. W.; Fehsenfeld, F. C.; Flocke, F.; Holecek, J. C.; Holloway, J. S.; Hübler, G.; Jakoubek, R.; Nicks, D. K.; Parrish, D. D.; Ryerson, T. B.; Sueper, D. T.; Weinheimer, A. J.

    2002-10-01

    Nitric acid (HNO3) was measured from an aircraft in the planetary boundary layer and free troposphere up to 7 km on 14 flights during the Texas Air Quality Study in August and September 2000. HNO3 mixing ratios were measured at 1 Hz using a fast-response chemical ionization mass spectrometer with SiF5- reagent ions. HNO3 measurement using this highly selective ion chemistry is insensitive to water vapor and is not degraded by interferences from other species. Rapid time response (1 s) was achieved using a heated Teflon inlet. In-flight standard addition calibrations from a HNO3 permeation source were used to determine the instrument sensitivity of 1.1 ± 0.1 ion counts pptv-1 s-1 over the duration of the study. Contributions to the HNO3 signal from instrument artifacts were accounted for by regularly performing in-flight instrument background checks, where HNO3 was removed from the ambient air sample by diverting the sampled air though a nylon wool scrubber. Measurement inaccuracy, which is determined from uncertainties in the standard addition calibrations, was ±10%. Measurement precision at low HNO3 levels was ±25 pptv (1σ) for the 1 Hz data and ±9 pptv for 10 s averages of the 1 s measurements. Coincident in situ measurements of other reactive nitrogen species are used to examine NOy partitioning and HNO3 formation during this month long measurement campaign. The sum of the individually measured reactive nitrogen species is shown to be in agreement with the measured NOy. HNO3 formation in plumes from electric utility power plants, urban areas, and petrochemical facilities was studied. The observed differences in the fractional contribution of HNO3 to NOy in plumes from different anthropogenic source types are discussed.

  10. Monitoring groundwater variation by satellite and implications for in-situ gravity measurements.

    PubMed

    Fukuda, Yoichi; Yamamoto, Keiko; Hasegawa, Takashi; Nakaegawa, Toshiyuki; Nishijima, Jun; Taniguchi, Makoto

    2009-04-15

    In order to establish a new technique for monitoring groundwater variations in urban areas, the applicability of precise in-situ gravity measurements and extremely high precision satellite gravity data via GRACE (Gravity Recovery and Climate Experiment) was tested. Using the GRACE data, regional scale water mass variations in four major river basins of the Indochina Peninsula were estimated. The estimated variations were compared with Soil-Vegetation-Atmosphere Transfer Scheme (SVATS) models with a river flow model of 1) globally uniform river velocity, 2) river velocity tuned by each river basin, 3) globally uniform river velocity considering groundwater storage, and 4) river velocity tuned by each river basin considering groundwater storage. Model 3) attained the best fit to the GRACE data, and the model 4) yielded almost the same values. This implies that the groundwater plays an important role in estimating the variation of total terrestrial storage. It also indicates that tuning river velocity, which is based on the in-situ measurements, needs further investigations in combination with the GRACE data. The relationships among GRACE data, SVATS models, and in-situ measurements were also discussed briefly.

  11. Orbital plane constraint applicable for in-situ measurement of sub-millimeter-size debris

    NASA Astrophysics Data System (ADS)

    Furumoto, Masahiro; Fujita, Koki; Hanada, Toshiya; Matsumoto, Haruhisa; Kitazawa, Yukihito

    2017-03-01

    Space debris smaller than 1 mm in size still have enough energy to cause a fatal damage on a spacecraft, but such tiny debris cannot be followed or tracked from the ground. Therefore, IDEA the project for In-situ Debris Environmental Awareness, which aims to detect sub-millimeter-size debris using a group of micro satellites, has been initiated at Kyushu University. First, this paper reviews the previous study on the nature of orbits on which debris may be detected through in-situ measurements proposed in the IDEA project. Second, this paper derives a simple equation that constrains the orbital plane on which debris is detected through in-situ measurements. Third, this paper also investigates the nature and sensitivity of this simple constraint equation to clear how frequently impacts have to be confirmed to reduce the measurement error. Finally, this paper introduces a torus model to describe the collision flux observed from the previous study approximately. This collision flux approximation agrees rather well with the observed collision flux. It is concluded, therefore, that the simple constraint equation and collision flux approximation introduced in this paper can replace the analytical method adopted by the previous study to conduct a further investigation more effectively.

  12. Challenging In-Situ Strain Measurement In Pneumatic Bulging Of AA5083

    NASA Astrophysics Data System (ADS)

    Liewald, M.; Kappes, J.

    2011-05-01

    Superplastic forming of sheet metal aluminum alloys exhibits numerous technical and economical advantages for manufacturing of complex part geometries in niche type production. For virtual engineering tasks prior manufacturing of superplastic forming equipment such as forming dies, numerical sheet metal forming simulations and material parameters are crucial. In such context the selected testing procedure should be as similar as possible to the subsequent forming technique. For that reason the pneumatic bulge test represents an appropriate testing procedure for the most common superplastic forming process—the blow forming process. In-situ strain measurement of pneumatic bulging AA5083 at 500° C results in high requirements in terms of the grid applied on the blank surface due to process temperature and large strain values. These large strain values result into pole heights up to 70 mm of the bulge test specimens using an initial blank thickness of 1.5 mm and a circular die opening of 100 mm. This paper describes the influence of different grid types and finally proposes adequate grid types for in-situ strain measurement for pneumatic bulging of AA5083. Furthermore the capabilities of in-situ measurement of strains during pneumatic bulging of AA5083 are highlighted.

  13. 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.

  14. Aircraft Transparency Optical Quality: New Methods of Measurement

    DTIC Science & Technology

    1981-02-01

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

  15. 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.

  16. Using Multiple Space Assests with In-Situ Measurements to Track Flooding in Thailand

    NASA Technical Reports Server (NTRS)

    Chien, Steve; Doubleday, Joshua; Mclaren, David; Tran, Daniel; Khunboa, Chatchai; Leelapatra, Watis; Pergamon, Vichain; Tanpipat, Veerachai; Chitradon, Royal; Boonya-aroonnet, Surajate; Thanapakpawin, Porranee; Meethome, Amara; Raghavendra, Cauligi (Raghu); Mandl, Daniel

    2001-01-01

    Increasing numbers of space assets can enable coordinated measurements of flooding phenomena to enhance tracking of extreme events. We describe the use of space and ground measurements to target further measurements as part of a flood monitoring system in Thailand. We utilize rapidly delivered MODIS data to detect major areas of flooding and the target the Earth Observing One Advanced Land Imager sensor to acquire higher spatial resolution data. Automatic surface water extent mapping products delivered to interested parties. We are also working to extend our network to include in-situ sensing networks and additional space assets.

  17. In situ exhaust cloud measurements. [particle size distribution and cloud physics of rocket exhaust clouds

    NASA Technical Reports Server (NTRS)

    Wornom, D.

    1980-01-01

    Airborne in situ exhaust cloud measurements were conducted to obtain definitions of cloud particle size range, Cl2 content, and HCl partitioning. Particle size distribution data and Cl2 measurements were made during the May, August, and September 1977 Titan launches. The measurements of three basic effluents - HCl, NO sub X, and particles - against minutes after launch are plotted. The maximum observed HCl concentration to the maximum Cl2 concentration are compared and the ratios of the Cl2 to the HCl is calculated.

  18. In-Situ Silver Acetylide Silver Nitrate Explosive Deposition Measurements Using X-Ray Fluorescence.

    SciTech Connect

    Covert, Timothy Todd

    2014-09-01

    The Light Initiated High Explosive facility utilized a spray deposited coating of silver acetylide - silver nitrate explosive to impart a mechanical shock into targets of interest. A diagnostic was required to measure the explosive deposition in - situ. An X - ray fluorescence spectrometer was deployed at the facility. A measurement methodology was developed to measure the explosive quantity with sufficient accuracy. Through the use of a tin reference material under the silver based explosive, a field calibration relationship has been developed with a standard deviation of 3.2 % . The effect of the inserted tin material into the experiment configuration has been explored.

  19. A Method to Measure the Flatness of the LSST Focal Plane Assembly in Situ

    SciTech Connect

    Langeveld, Willy; /SLAC

    2005-10-26

    In this note I describe an inexpensive and simple laser-based method to measure the flatness of the LSST focal plane assembly (FPA) in situ, i.e. while the FPA is inside its cryostat, at -100 C and under vacuum. The method may also allow measurement of the distance of the FPA to lens L3, and may be sensitive enough to measure gravity- and pressure-induced deformations of L3 as well. The accuracy of the method shows promise to be better than 1 micron.

  20. In situ global method for measurement of oxygen demand and mass transfer

    SciTech Connect

    Klasson, K.T.; Lundbaeck, K.M.O.; Clausen, E.C.; Gaddy, J.L.

    1997-05-01

    Two aerobic microorganisms, Saccharomycopsis lipolytica and Brevibacterium lactofermentum, have been used in a study of mass transfer and oxygen uptake from a global perspective using a closed gas system. Oxygen concentrations in the gas and liquid were followed using oxygen electrodes, and the results allowed for easy calculation of in situ oxygen transport. The cell yields on oxygen for S. lipolytica and B. lactofermentum were 1.01 and 1.53 g/g respectively. The mass transfer coefficient was estimated as 10 h{sup {minus}1} at 500 rpm for both fermentations. The advantages with this method are noticeable since the use of model systems may be avoided, and the in situ measurements of oxygen demand assure reliable data for scale-up.

  1. A new technique for in situ measurement of the composition of neutral gas in interplanetary space

    NASA Technical Reports Server (NTRS)

    Gruntman, Michael A.

    1993-01-01

    Neutral atoms in interplanetary space play an important role in many processes relevant to the formation and evolution of the Solar System. An experimental approach is proposed for in situ atom detection based on the conversion of neutral atoms to negative ions at a specially prepared sensitive surface. Negative ions are subsequently analyzed and detected in an essentially noise-free mode. The use of the technique for in situ study of the composition of neutral interstellar atoms is considered. It is shown that interstellar H, D, and O atoms and possibly H2 molecules can be measured by the proposed technique. The experiment can be performed from a high-apogee Earth-orbiting satellite or from a deep space probe. Possible applications of the technique are discussed.

  2. In situ growth rate measurements by normal-incidence reflectance during MOVPE growth

    SciTech Connect

    Hou, H.Q.; Breiland, W.G.; Hammons, B.E.; Chui, H.C.

    1996-05-01

    We present an in situ technique for monitoring metal-organic vapor phase epitaxy growth by normal-incidence reflectance. This technique is used to calibrate the growth rate periodically and to monitor the growth process routinely. It is not only a precise tool to measure the growth rate, but also very useful in identifying unusal problems during a growth run, such as depletion of source material, deterioration of surface morphology, and problems associated with an improper growht procedure. We will also present an excellent reproducibility ({+-}0.3% over a course of more than 100 runs) of the cavity wavelength of vertical-cavity surface emitting laser structures with periodic calibration by this in situ technique.

  3. A Multi-Pumping Flow System for In Situ Measurements of Dissolved Manganese in Aquatic Systems

    PubMed Central

    Meyer, David; Prien, Ralf D.; Dellwig, Olaf; Waniek, Joanna J.; Schuffenhauer, Ingo; Donath, Jan; Krüger, Siegfried; Pallentin, Malte; Schulz-Bull, Detlef E.

    2016-01-01

    A METals In Situ analyzer (METIS) has been used to determine dissolved manganese (II) concentrations in the subhalocline waters of the Gotland Deep (central Baltic Sea). High-resolution in situ measurements of total dissolved Mn were obtained in near real-time by spectrophotometry using 1-(2-pyridylazo)-2-naphthol (PAN). PAN is a complexing agent of dissolved Mn and forms a wine-red complex with a maximum absorbance at a wavelength of 562 nm. Results are presented together with ancillary temperature, salinity, and dissolved O2 data. Lab calibration of the analyzer was performed in a pressure testing tank. A detection limit of 77 nM was obtained. For validation purposes, discrete water samples were taken by using a pump-CTD system. Dissolved Mn in these samples was determined by an independent laboratory based method (inductively coupled plasma–optical emission spectrometry, ICP-OES). Mn measurements from both METIS and ICP-OES analysis were in good agreement. The results showed that the in situ analysis of dissolved Mn is a powerful technique reducing dependencies on heavy and expensive equipment (pump-CTD system, ICP-OES) and is also cost and time effective. PMID:27916898

  4. Visible and near-infrared imaging spectrometer (VNIS) for in-situ lunar surface measurements

    NASA Astrophysics Data System (ADS)

    He, Zhiping; Xu, Rui; Li, Chunlai; Lv, Gang; Yuan, Liyin; Wang, Binyong; Shu, Rong; Wang, Jianyu

    2015-10-01

    The Visible and Near-Infrared Imaging Spectrometer (VNIS) onboard China's Chang'E 3 lunar rover is capable of simultaneously in situ acquiring full reflectance spectra for objects on the lunar surface and performing calibrations. VNIS uses non-collinear acousto-optic tunable filters and consists of a VIS/NIR imaging spectrometer (0.45-0.95 μm), a shortwave IR spectrometer (0.9-2.4 μm), and a calibration unit with dust-proofing functionality. To been underwent a full program of pre-flight ground tests, calibrations, and environmental simulation tests, VNIS entered into orbit around the Moon on 6 December 2013 and landed on 14 December 2013 following Change'E 3. The first operations of VNIS were conducted on 23 December 2013, and include several explorations and calibrations to obtain several spectral images and spectral reflectance curves of the lunar soil in the Imbrium region. These measurements include the first in situ spectral imaging detections on the lunar surface. This paper describes the VNIS characteristics, lab calibration, in situ measurements and calibration on lunar surface.

  5. In Situ Thermal Characterization of Cooling/Crystallising Lavas During Rheology Measurement.

    NASA Astrophysics Data System (ADS)

    Kolzenburg, S.; Giordano, D.; Cimarelli, C.; Dingwell, D. B.

    2015-12-01

    Transport properties of silicate melts at super-liquidus temperatures are reasonably well understood. Migration and transport of silicate melts in the earth's crust and at its surface generally occur at sub-liquidus temperature regimes where they are subject to non-isothermal and non-equilibrium crystallization. To date, rheological data at sub-liquidus temperatures are scarce. In such dynamic situations heat capacities, latent heats of phase changes, viscous heating, thermal advection and thermal inertia of the apparatus are all potential factors in determining the thermal regime. Yet thermal characterisation of non- equilibrium conditions are absent, hampered by the inconvenience of recording in situ sample temperature during dynamic rheological measurements. Here we present a new experimental setup for in situ sample temperature monitoring in high temperature rheometry. We overcome the limitation of hardwired thermocouples during sample deformation by employing wireless data transmitters directly mounted onto the rotating spindle, immersed in the sample. This adaptation enables in situ, real-time, observations of the thermal regime of crystallising, deforming lava samples under the transient and non-equilibrium crystallization conditions expected in lava flows in nature. We present the apparatus calibration procedure, assess the experimental uncertainty in viscosity measurements and discuss experimental data investigating the dynamic, rheologic and thermal evolution of lavas in both temperature step and continuous cooling experiments.

  6. A Multi-Pumping Flow System for In Situ Measurements of Dissolved Manganese in Aquatic Systems.

    PubMed

    Meyer, David; Prien, Ralf D; Dellwig, Olaf; Waniek, Joanna J; Schuffenhauer, Ingo; Donath, Jan; Krüger, Siegfried; Pallentin, Malte; Schulz-Bull, Detlef E

    2016-11-30

    A METals In Situ analyzer (METIS) has been used to determine dissolved manganese (II) concentrations in the subhalocline waters of the Gotland Deep (central Baltic Sea). High-resolution in situ measurements of total dissolved Mn were obtained in near real-time by spectrophotometry using 1-(2-pyridylazo)-2-naphthol (PAN). PAN is a complexing agent of dissolved Mn and forms a wine-red complex with a maximum absorbance at a wavelength of 562 nm. Results are presented together with ancillary temperature, salinity, and dissolved O 2 data. Lab calibration of the analyzer was performed in a pressure testing tank. A detection limit of 77 nM was obtained. For validation purposes, discrete water samples were taken by using a pump-CTD system. Dissolved Mn in these samples was determined by an independent laboratory based method (inductively coupled plasma-optical emission spectrometry, ICP-OES). Mn measurements from both METIS and ICP-OES analysis were in good agreement. The results showed that the in situ analysis of dissolved Mn is a powerful technique reducing dependencies on heavy and expensive equipment (pump-CTD system, ICP-OES) and is also cost and time effective.

  7. SeaWiFS Aerosol Product Compared to Coastal and Island in situ Measurements

    NASA Astrophysics Data System (ADS)

    Bailey, S.; Pietras, C.; Knobelspiesse, K.; Fargion, G.; McClain, C.

    2002-05-01

    The Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS, http://simbios.gsfc.nasa.gov) Project is assisting the ocean color community to cross calibrate and merge data products from multiple ocean color missions. The atmospheric contribution plays an essential role in the analysis of the ocean color imagery. The correction of the atmospheric contribution is a crucial procedure that requires in situ measurements of atmospheric and bio-optical components to compare and validate satellite measurements. The SIMBIOS Project is using in situ atmospheric data for several purposes including validation of the SeaWiFS and other ocean color missions aerosol optical product, evaluation of the aerosol models currently used for atmospheric correction, and development of vicarious sensor calibration methodologies. The principal source of in situ aerosol observations is the Aerosol Robotic Network (AERONET) that provides globally distributed, near-real time, observations of spectral aerosol optical depths, aerosol size distributions and precipitable water. Since 1997 the SIMBIOS Project has augmented the AERONET network with 12 additional island and coastal sites, including the Hawaiian Islands (Lanai and Oahu), Ascension Island, Bahrain, Tahiti, Wallops Island (US East Coast), South Korea, Turkey, Argentina, Azores, and Australia and more recently Morocco. The AERONET and SIMBIOS Projects have invested considerable effort to deploy and maintain the instruments to ensure the quality of the data for more than 4 years. Match-ups between aerosol optical thickness obtained for various sites from in situ and satellite-derived observations are presented and discussed. Match-up analysis methods and uncertainties are also discussed.

  8. Outlet-glacier flow dynamics estimation combining in-situ and spaceborne SAR measurements

    NASA Astrophysics Data System (ADS)

    Rohner, Christoph; Henke, Daniel; Small, David; Mercenier, Rémy; Lüthi, Martin; Vieli, Andreas

    2016-04-01

    Terminus retreat and flow acceleration changes of ocean-terminating outlet glaciers contribute significantly to the current mass loss of the Greenland Ice Sheet and therefore to global sea level rise. In order to constrain models ice dynamics, detailed knowledge of geometry, ice-flow velocity and strain fields of such calving glaciers is needed. Of specific importance is the near terminus flow dynamics, as the flow fields there are highly influential on the glacier's calving rate. With the current temporal resolution of spaceborne radar systems, it is difficult to accurately capture the near terminus flow fields for fast moving outlet glaciers glaciers, while in-situ measurements using ground based radar interferometers are limited in coverage and constrained by distance and geometric shading of the glacier. We present and analyze the combined continuous velocity fields from a ground based, portable radar system as well as from spaceborne SAR scenes for Eqip Sermia, a medium-sized ocean terminating outlet glacier in western Greenland. The flow fields for the spaceborne data are calculated using feature tracking with a temporal resolution of 12 and 24 days for Sentinel-1 (Interferometric Wide Swath) and RADARSAT-2 (Ultra Fine/Fine Quad) respectively. The in-situ terrestrial radar data were recorded at one minute intervals were additionally processed using interferometry. The combination of in-situ and spaceborne radar enables a spatially continuous assessment of the strain fields of the ocean terminating outlet glacier. An assimilation of the data based on areas with both in-situ and spaceborne measurements is carried out and the results are compared to historical strain field data sets. These data ultimately provide constraints for a physical fracture and damage model.

  9. In-situ geophysical measurements in marine sediments: Applications in seafloor acoustics and paleoceanography

    NASA Astrophysics Data System (ADS)

    Gorgas, Thomas Joerg

    Acoustic in-situ sound speeds and attenuation were measured on the Eel River shelf, CA, with the Acoustic Lance between 5 and 15 kHz to 2.0 meters below seafloor (mbsf). A comparison with laboratory ultrasonic geoacoustic data obtained at 400 kHz on cored sediments showed faster in-situ and ultrasonic sound speeds in coarse-grained deposits in water depths to 60 m than in fine-grained deposits below that contour line. Ultrasonic attenuation was often greater than in-situ values and remained almost constant below 0.4 mbsf in these heterogeneous deposits. In-situ attenuation decreased with depth. These observations partly agree with results from other field studies, and with theoretical models that incorporate intergranular friction and dispersion from viscosity as main controls on acoustic wave propagation in marine sediments. Deviations among in-situ and laboratory acoustic data from the Eel Margin with theoretical studies were linked to scattering effects. Acoustic Lance was also deployed in homogeneous, fine-grained sediments on the inner shelf of SE Korea, where free gas was identified in late-September, but not in mid-September 1999. Free gas was evidenced by an abrupt decrease of in-situ sound speed and by characteristic changes in acoustic waveforms. These results suggest the presence of a gassy sediment layer as shallow as 2 mbsf along the 70 m bathymetry line, and was attributed to a variable abundance of free gas on short-term and/or small-regional scales on the SE Korea shelf. Bulk density variations in marine sediments obtained along the Walvis Ridge/Basin, SW Africa, at Ocean Drilling Program (ODP) Sites 1081 to 1084 were spectral-analyzed to compute high-resolution sedimentation rates (SRs) in both the time- and age domains by correctly identifying Milankovitch cycles (MCs). SRs for the ODP sites yielded age-depth models that often correlate positively with biostratigraphic data and with organic mass accumulation rates (MAR Corg), a proxy for

  10. Integrated Airborne and In-Situ Measurements Over Land-Fast Ice Near Barrow, AK.

    NASA Astrophysics Data System (ADS)

    Gardner, J. M.; Brozena, J. M.; Richter-Menge, J.; Abelev, A.; Liang, R.; Ball, D.; Claffey, K. J.; Hebert, D. A.; Jones, K.

    2015-12-01

    The Naval Research Laboratory has collected two field seasons of integrated airborne and in-situ measurements over multiple sites of floating, but land-fast ice north of Barrow, AK. During the first season in March of 2014 the Cold Regions Research and Engineering Laboratory led the on-ice group including NRL personnel and Naval Academy midshipmen. The second season (March 2015) included only NRL scientists and midshipmen. The in-situ data provided ground-truth for airborne measurements from a scanning LiDAR (Riegl Q 560i), digital photogrammetry (Applanix DSS-439), a low-frequency SAR (P-band in 2014 and P and L bands in 2015) and a snow/Ku radar procured from the Center for Remote Sensing of Ice Sheets of the University of Kansas. The CReSIS radar was updated in 2015 to integrate the snow and Ku radars into a single continuous chirp, thus improving resolution. The objective of the survey was to aid our understanding of the use of the airborne data to calibrate/validate Cryosat-2 data. Sampling size or "footprint" plays a critical role in the attempt to compare in-situ measurements with airborne (or satellite) measurements. Thus the in-situ data were arranged to minimize aliasing. Ground measurements were collected along transects a sites generally consisting of a 2 km long profile of Magnaprobe and EM31 measurements with periodic boreholes. A 60 m x 400 m swath of Magnaprobe measurements was centered on this profile. Airborne data were collected on multiple overflights of the transect areas. The LiDAR measured total freeboard (ice + snow) referenced to leads in the ice, and produced swaths 200-300 m wide. The SAR imaged the ice beneath the snow and the snow/Ku radar measured snow thickness. The freeboard measurements and snow thickness are used to estimate ice thickness via isostasy and density estimates. Comparisons and processing methodology will be shown. The results of this ground-truth experiment will inform our analysis of grids of airborne data collected

  11. Manipulation of Samples at Extreme Temperatures for Fast in-situ Synchrotron Measurements

    SciTech Connect

    Weber, Richard

    2016-04-22

    An aerodynamic sample levitation system with laser beam heating was integrated with the APS beamlines 6 ID-D, 11 ID-C and 20 BM-B. The new capability enables in-situ measurements of structure and XANES at extreme temperatures (300-3500 °C) and in conditions that completely avoid contact with container surfaces. In addition to maintaining a high degree of sample purity, the use of aerodynamic levitation enables deep supercooling and greatly enhanced glass formation from a wide variety of melts and liquids. Development and integration of controlled extreme sample environments and new measurement techniques is an important aspect of beamline operations and user support. Processing and solidifying liquids is a critical value-adding step in manufacturing semiconductors, optical materials, metals and in the operation of many energy conversion devices. Understanding structural evolution is of fundamental importance in condensed materials, geology, and biology. The new capability provides unique possibilities for materials research and helps to develop and maintain a competitive materials manufacturing and energy utilization industry. Test samples were used to demonstrate key features of the capability including experiments on hot crystalline materials, liquids at temperatures from about 500 to 3500 °C. The use of controlled atmospheres using redox gas mixtures enabled in-situ changes in the oxidation states of cations in melts. Significant innovations in this work were: (i) Use of redox gas mixtures to adjust the oxidation state of cations in-situ (ii) Operation with a fully enclosed system suitable for work with nuclear fuel materials (iii) Making high quality high energy in-situ x-ray diffraction measurements (iv) Making high quality in-situ XANES measurements (v) Publishing high impact results (vi) Developing independent funding for the research on nuclear materials This SBIR project work led to a commercial instrument product for the niche market of processing and

  12. [In situ temperature measurement by absorption spectroscopy based on time division multiplexing technology].

    PubMed

    Lou, Nan-zheng; Li, Ning; Weng, Chun-sheng

    2012-05-01

    Tunable diode laser absorption spectroscopy (TDLAS) technology is a kind of high sensitivity, high selectivity of non contacting gas in situ measurement technique. In the present paper, in situ gas temperature measurement of an open environment was achieved by means of direct scanning multiple characteristic lines of H2O and combined with least-squares algorithm. Through the use of HITRAN spectral database, the boundary effect on the gas temperature and concentration measurements was discussed in detail, and results showed that the combination of scanning multiple characteristic lines and least-squares algorithm can effectively reduce the boundary effect on the gas temperature measurements under the open environment. Experiments using time division multiplexing technology to simultaneously scan 7444.36, 7185.60, 7182.95 and 7447.48 cm(-1), the four characteristic H2O lines, the gas temperature of tubular furnace in the range of 573-973 K was measured under different conditions. The maximum temperature difference between absorption spectrum measurement and thermocouple signal was less than 52.4 K, and the maximum relative error of temperature measurement was 6.8%.

  13. Simultaneous in-situ measurements of mesospheric temperature inversion layers and turbulence

    NASA Astrophysics Data System (ADS)

    Strelnikov, Boris; Rapp, Markus

    For several decades rocket borne ionization gauges have been used to obtain observations of mesospheric turbulence and temperature-profiles. The main advantage of these in-situ turbu-lence measurements is that they are made at very high spatial resolution and cover a wide range of spatial scales. This makes it possible to study the spectral content of the turbulent eddies in the range of spatial scales from tens of centimeters to some kilometers. Spectral analysis of these data yields turbulent energy dissipation rates at a spatial resolution of about 100 m. This reveals the highly patchy structure of MLT turbulence. Our measurements of-ten show adjacent regions with very strong turbulence and non-turbulent layers on vertical scales as short as some kilometers. Some observations even show turbulence layers which are only some hundreds of meters thick. Most of these turbulence measurements were accompa-nied by simultaneous common volume temperature measurements. Among those simultaneous measurements temperature inversion layers were often observed. In the present paper we analyze simultaneous in-situ measurements of mesospheric temperature inversion layers and turbulence measurements. This study includes about 30 sounding rocket flights launched at high northern latitudes. We compare morphology of the turbulence field with temperature profiles to gain a deeper insight how temperature inversions are related to local turbulence activity.

  14. Removal of correlated noise online for in situ measurements by using multichannel magnetic resonance sounding system

    NASA Astrophysics Data System (ADS)

    Lin, Tingting; Zhang, Siyuan; Zhang, Yang; Wan, Ling; Lin, Jun

    2017-01-01

    Compared with the other geophysical approaches, magnetic resonance sounding (MRS) technique is direct and nondestructive in subsurface water exploration. It provides water content distribution and estimates hydrogeological properties. The biggest challenge is that MRS measurement always suffers bad signal-to-noise ratio, and it can be carried out only far from sources of noise. To solve this problem, a series of de-noising methods are developed. However, most of them are post-processing, leading the data quality uncontrolled for in situ measurements. In the present study, a new approach that removal of correlated noise online is found to overcome the restriction. Based on LabVIEW, a method is provided to enable online data quality control by the way of realizing signal acquisition and noise filtering simultaneously. Using one or more reference coils, adaptive noise cancellation based on LabVIEW to eliminate the correlated noise is available for in situ measurements. The approach was examined through numerical simulation and field measurements. The correlated noise is mitigated effectively and the application of MRS measurements is feasible in high-level noise environment. The method shortens the measurement time and improves the measurement efficiency.

  15. Quantifying precision of in situ length and weight measurements of fish

    USGS Publications Warehouse

    Gutreuter, S.; Krzoska, D.J.

    1994-01-01

    We estimated and compared errors in field-made (in situ) measurements of lengths and weights of fish. We made three measurements of length and weight on each of 33 common carp Cyprinus carpio, and on each of a total of 34 bluegills Lepomis macrochirus and black crappies Pomoxis nigromaculatus. Maximum total lengths of all fish were measured to the nearest 1 mm on a conventional measuring board. The bluegills and black crappies (85–282 mm maximum total length) were weighed to the nearest 1 g on a 1,000-g spring-loaded scale. The common carp (415–600 mm maximum total length) were weighed to the nearest 0.05 kg on a 20-kg spring-loaded scale. We present a statistical model for comparison of coefficients of variation of length (Cl ) and weight (Cw ). Expected Cl was near zero and constant across mean length, indicating that length can be measured with good precision in the field. Expected Cw decreased with increasing mean length, and was larger than expected Cl by 5.8 to over 100 times for the bluegills and black crappies, and by 3 to over 20 times for the common carp. Unrecognized in situ weighing errors bias the apparent content of unique information in weight, which is the information not explained by either length or measurement error. We recommend procedures to circumvent effects of weighing errors, including elimination of unnecessary weighing from routine monitoring programs. In situ weighing must be conducted with greater care than is common if the content of unique and nontrivial information in weight is to be correctly identified.

  16. Mapping Particulate Matter in the European Alps from Modis, Seviri, and In-Situ Measurements

    NASA Astrophysics Data System (ADS)

    Petitta, M.; Emili, E.; Popp, C. T.; Wunderle, S.; Zebisch, M.

    2011-12-01

    In this study, we investigate the spatially homogenous mapping of particulate matter over the complex topography of the European Alpine region by means of remote sensing and ground-based measurements. Knowledge about the spatio-temporal distribution and atmospheric evolution of particulate matter is of great interest because higher levels of PM can affect human health and therefore, such information can be used by authorities to take counteractions like e.g. traffic restrictions. The study area is frequently influenced by high PM concentrations, especially when atmospheric inversions occur during winter. Major anthropogenic aerosol sources in the European Alps include traffic, wood burning for heating and cooking, and industrial activities. Wefirst apply a linear model to relate aerosol optical depth (AOD) from the geostationary Spinning Enhanced Visible and InfraRed Imager (SEVIRI) and polar orbiting Moderate Resolution Imaging Spectroradiometer (MODIS) together with boundary layer height (BLH) to surface PM10 concentrations in order to derive spatially homogenous maps of PM10 over the study region for 2008-2009. In parallel, maps of PM10 are computed by inverse distance interpolation of in-situ measurements. Both (SEVIRI and MODIS) satellite based PM10 estimates reveal a moderate performance with a correlation coefficient (R) of ~0.6 and a root mean square error (RMSE) of around 10 μg m-1. In contrary, the sole inverse distance interpolation of in-situ measurements produces more accurate PM10 maps (R~0.8, RMSE < 6 μg m-1). Subsequently, the two separate maps are combined through an assimilation scheme where the interpolated maps serve as background field which is up-dated by the satellite product. However, this step only leads to a small improvement in accuracy when most of the in-situ sites are excluded from the interpolation simulating a much sparser network. We conclude that satellite based PM10 maps in the European Alpine region are of limited additional

  17. Particulate matter mapping in the European Alps from MODIS, SEVIRI, and in-situ measurements

    NASA Astrophysics Data System (ADS)

    Emili, E.; Popp, C.; Zebisch, M.; Wunderle, S.; Petitta, M.

    2012-04-01

    In this study, we investigate the spatially homogenous mapping of particulate matter over the complex topography of the European Alpine region by means of remote sensing and ground-based measurements. Knowledge about the spatio-temporal distribution and atmospheric evolution of particulate matter is of great interest because higher levels of PM can affect human health and therefore, such information can be used by authorities to take counteractions like e.g. traffic restrictions. The study area is frequently influenced by high PM concentrations, especially when atmospheric inversions occur during winter. Major anthropogenic aerosol sources in the European Alps include traffic, wood burning for heating and cooking, and industrial activities. Wefirst apply a linear model to relate aerosol optical depth (AOD) from the geostationary Spinning Enhanced Visible and InfraRed Imager (SEVIRI) and polar orbiting Moderate Resolution Imaging Spectroradiometer (MODIS) together with boundary layer height (BLH) to surface PM10 concentrations in order to derive spatially homogenous maps of PM10 over the study region for 2008-2009. In parallel, maps of PM10 are computed by inverse distance interpolation of in-situ measurements. Both (SEVIRI and MODIS) satellite based PM10 estimates reveal a moderate performance with a correlation coefficient (R) of ~0.6 and a root mean square error (RMSE) of around 10 μg m-1. In contrary, the sole inverse distance interpolation of in-situ measurements produces more accurate PM10 maps (R~0.8, RMSE < 6 μg m-1). Subsequently, the two separate maps are combined through an assimilation scheme where the interpolated maps serve as background field which is up-dated by the satellite product. However, this step only leads to a small improvement in accuracy when most of the in-situ sites are excluded from the interpolation simulating a much sparser network. We conclude that satellite based PM10 maps in the European Alpine region are of limited additional

  18. Validation of Land Surface Temperature products in arid climate regions with permanent in-situ measurements

    NASA Astrophysics Data System (ADS)

    Goettsche, F.; Olesen, F.; Trigo, I.; Hulley, G. C.

    2013-12-01

    Land Surface Temperature (LST) is operationally obtained from several space-borne sensors, e.g. from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) onboard Meteosat Second Generation (MSG) by the Land Surface Analysis - Satellite Application Facility (LSA-SAF) and from the Moderate Resolution Imaging Spectroradiometer (MODIS) on EOS-Terra by the MODIS Land Team. The relative accuracy of LST products can be assessed by cross-validating different products. Alternatively, the so-called 'radiance based validation' can be used to compare satellite-retrieved LST with results from radiative transfer models: however, this requires precise a priori knowledge of land surface emissivity (LSE) and atmospheric conditions. Ultimately, in-situ measurements (';ground truth') are needed for validating satellite LST&E products. Therefore, the LST product derived by LSA-SAF is validated with independent in-situ measurements (';temperature based validation') at permanent validation stations located in different climate regions on the SEVIRI disk. In-situ validation is largely complicated by the spatial scale mismatch between satellite sensors and ground based sensors, i.e. areas observed by ground radiometers usually cover about 10 m2, whereas satellite measurements in the thermal infrared typically cover between 1 km2 and 100 km2. Furthermore, an accurate characterization of the surface is critical for all validation approaches, but particularly over arid regions, as shown by in-situ measurements revealing that LSE products can be wrong by more than 3% [1]. The permanent stations near Gobabeb (Namibia; hyper-arid desert climate) and Dahra (Senegal; hot-arid steppe-prairie climate) are two of KIT's four dedicated LST validation stations. Gobabeb station is located on vast and flat gravel plains (several 100 km2), which are mainly covered by coarse gravel, sand, and desiccated grass. The gravel plains are highly homogeneous in space and time, which makes them ideal for

  19. In situ measurements of volatile aromatic hydrocarbon biodegradation rates in groundwater

    USGS Publications Warehouse

    Cozzarelli, I.M.; Bekins, B.A.; Eganhouse, R.P.; Warren, E.; Essaid, H.I.

    2010-01-01

    Benzene and alkylbenzene biodegradation rates and patterns were measured using an in situ microcosm in a crude-oil contaminated aquifer near Bemidji, Minnesota. Benzene-D6, toluene, ethylbenzene, o-, m- and p-xylenes and four pairs of C3- and C4-benzenes were added to an in situ microcosm and studied over a 3-year period. The microcosm allowed for a mass-balance approach and quantification of hydrocarbon biodegradation rates within a well-defined iron-reducing zone of the anoxic plume. Among the BTEX compounds, the apparent order of persistence is ethylbenzene > benzene > m,p-xylenes > o-xylene ≥ toluene. Threshold concentrations were observed for several compounds in the in situ microcosm, below which degradation was not observed, even after hundreds of days. In addition, long lag times were observed before the onset of degradation of benzene or ethylbenzene. The isomer-specific degradation patterns were compared to observations from a multi-year study conducted using data collected from monitoring wells along a flowpath in the contaminant plume. The data were fit with both first-order and Michaelis-Menten models. First-order kinetics provided a good fit for hydrocarbons with starting concentrations below 1 mg/L and Michaelis-Menten kinetics were a better fit when starting concentrations were above 1 mg/L, as was the case for benzene. The biodegradation rate data from this study were also compared to rates from other investigations reported in the literature.

  20. In situ measurements of volatile aromatic hydrocarbon biodegradation rates in groundwater.

    PubMed

    Cozzarelli, Isabelle M; Bekins, Barbara A; Eganhouse, Robert P; Warren, Ean; Essaid, Hedeff I

    2010-01-15

    Benzene and alkylbenzene biodegradation rates and patterns were measured using an in situ microcosm in a crude-oil contaminated aquifer near Bemidji, Minnesota. Benzene-D6, toluene, ethylbenzene, o-, m- and p-xylenes and four pairs of C(3)- and C(4)-benzenes were added to an in situ microcosm and studied over a 3-year period. The microcosm allowed for a mass-balance approach and quantification of hydrocarbon biodegradation rates within a well-defined iron-reducing zone of the anoxic plume. Among the BTEX compounds, the apparent order of persistence is ethylbenzene > benzene > m,p-xylenes > o-xylene >or= toluene. Threshold concentrations were observed for several compounds in the in situ microcosm, below which degradation was not observed, even after hundreds of days. In addition, long lag times were observed before the onset of degradation of benzene or ethylbenzene. The isomer-specific degradation patterns were compared to observations from a multi-year study conducted using data collected from monitoring wells along a flowpath in the contaminant plume. The data were fit with both first-order and Michaelis-Menten models. First-order kinetics provided a good fit for hydrocarbons with starting concentrations below 1mg/L and Michaelis-Menten kinetics were a better fit when starting concentrations were above 1mg/L, as was the case for benzene. The biodegradation rate data from this study were also compared to rates from other investigations reported in the literature.

  1. In Situ Measurements of the Dynamics of A Full Scale Bottom Moored Mine Model

    DTIC Science & Technology

    1993-06-01

    A4P/?o 7935 WHOI-93-21 In Situ Measurements of the Dynamics - of A Full Scale Bottom Moored Mine Model by H.O. Berteaux, A. Bocconcelli, C. Eck and S...BOTTOM MOORED MINE MODEL by H.O. BERTEAUX, A. BOCCONCELLI, C. ECK, S. KERY Woods Hole Oceanographic Institution Woods Hole, Massachusetts 02543 -"iSi...of the Woods Hole Oceanographic Institution devised (1991) and conducted (1992) an experiment to measure the dynamic response of a full scale model

  2. Simulated plasma facing component measurements for an in situ surface diagnostic on Alcator C-Mod

    SciTech Connect

    Hartwig, Z. S.; Whyte, D. G.

    2010-10-15

    The ideal in situ plasma facing component (PFC) diagnostic for magnetic fusion devices would perform surface element and isotope composition measurements on a shot-to-shot ({approx}10 min) time scale with {approx}1 {mu}m depth and {approx}1 cm spatial resolution over large areas of PFCs. To this end, the experimental adaptation of the customary laboratory surface diagnostic - nuclear scattering of MeV ions - to the Alcator C-Mod tokamak is being guided by ACRONYM, a Geant4 synthetic diagnostic. The diagnostic technique and ACRONYM are described, and synthetic measurements of film thickness for boron-coated PFCs are presented.

  3. Simulated plasma facing component measurements for an in situ surface diagnostic on Alcator C-Moda)

    NASA Astrophysics Data System (ADS)

    Hartwig, Z. S.; Whyte, D. G.

    2010-10-01

    The ideal in situ plasma facing component (PFC) diagnostic for magnetic fusion devices would perform surface element and isotope composition measurements on a shot-to-shot (˜10 min) time scale with ˜1 μm depth and ˜1 cm spatial resolution over large areas of PFCs. To this end, the experimental adaptation of the customary laboratory surface diagnostic—nuclear scattering of MeV ions—to the Alcator C-Mod tokamak is being guided by ACRONYM, a Geant4 synthetic diagnostic. The diagnostic technique and ACRONYM are described, and synthetic measurements of film thickness for boron-coated PFCs are presented.

  4. In situ gas analysis for high pressure applications using property measurements

    NASA Astrophysics Data System (ADS)

    Moeller, J.; Span, R.; Fieback, T.

    2013-10-01

    As the production, distribution, and storage of renewable energy based fuels usually are performed under high pressures and as there is a lack of in situ high pressure gas analysis instruments on the market, the aim of this work was to develop a method for in situ high pressure gas analysis of biogas and hydrogen containing gas mixtures. The analysis is based on in situ measurements of optical, thermo physical, and electromagnetic properties in gas mixtures with newly developed high pressure sensors. This article depicts the calculation of compositions from the measured properties, which is carried out iteratively by using highly accurate equations of state for gas mixtures. The validation of the method consisted of the generation and measurement of several mixtures, of which three are presented herein: a first mixture of 64.9 mol. % methane, 17.1 mol. % carbon dioxide, 9 mol. % helium, and 9 mol. % ethane at 323 K and 423 K in a pressure range from 2.5 MPa to 17 MPa; a second mixture of 93.0 mol. % methane, 4.0 mol. % propane, 2.0 mol. % carbon dioxide, and 1.0 mol. % nitrogen at 303 K, 313 K, and 323 K in a pressure range from 1.2 MPa to 3 MPa; and a third mixture of 64.9 mol. % methane, 30.1 mol. % carbon dioxide, and 5.0 mol. % nitrogen at 303 K, 313 K, and 323 K in a pressure range from 2.5 MPa to 4 MPa. The analysis of the tested gas mixtures showed that with measured density, velocity of sound, and relative permittivity the composition can be determined with deviations below 1.9 mol. %, in most cases even below 1 mol. %. Comparing the calculated compositions with the generated gas mixture, the deviations were in the range of the combined uncertainty of measurement and property models.

  5. Methyl mercury dynamics in a tidal wetland quantified using in situ optical measurements

    USGS Publications Warehouse

    Bergamaschi, B.A.; Fleck, J.A.; Downing, B.D.; Boss, E.; Pellerin, B.; Ganju, N.K.; Schoellhamer, D.H.; Byington, A.A.; Heim, W.A.; Stephenson, M.; Fujii, R.

    2011-01-01

    We assessed monomethylmercury (MeHg) dynamics in a tidal wetland over three seasons using a novel method that employs a combination of in situ optical measurements as concentration proxies. MeHg concentrations measured over a single spring tide were extended to a concentration time series using in situ optical measurements. Tidal fluxes were calculated using modeled concentrations and bi-directional velocities obtained acoustically. The magnitude of the flux was the result of complex interactions of tides, geomorphic features, particle sorption, and random episodic events such as wind storms and precipitation. Correlation of dissolved organic matter quality measurements with timing of MeHg release suggests that MeHg is produced in areas of fluctuating redox and not limited by buildup of sulfide. The wetland was a net source of MeHg to the estuary in all seasons, with particulate flux being much higher than dissolved flux, even though dissolved concentrations were commonly higher. Estimated total MeHg yields out of the wetland were approximately 2.5 μg m−2 yr−1—4–40 times previously published yields—representing a potential loading to the estuary of 80 g yr−1, equivalent to 3% of the river loading. Thus, export from tidal wetlands should be included in mass balance estimates for MeHg loading to estuaries. Also, adequate estimation of loads and the interactions between physical and biogeochemical processes in tidal wetlands might not be possible without long-term, high-frequency in situ measurements.

  6. In situ method for real time measurement of dielectric film thickness in plasmas

    SciTech Connect

    Jang, Sung-Ho; Kim, Gun-Ho; Chung, Chin-Wook

    2010-01-15

    An in situ thickness measurement method of dielectric films (dual frequency method) was developed, and the thicknesses were measured in an inductively coupled plasma. This method uses a small ac bias voltage with two frequencies for thickness measurement. The dielectric thickness is obtained from measuring the amplitudes of the two frequency ac currents through a sensor, as well as using an equivalent circuit model describing impedance of the dielectric film and the plasma sheath. In the experiment, the thicknesses of Al{sub 2}O{sub 3} film could be accurately measured in real time. To check the measurement reliability, the dual frequency method was compared with reflection spectrophotometry as a technique for optical thickness diagnostics. It was found that the dual frequency method agrees closely with reflection spectrophotometry at various rf powers and pressures. In addition, this method is very simple and can be installed anywhere in plasma reactors, in contrast with optical methods; therefore, it is expected to be applied to in situ surface diagnostics for various processing plasmas.

  7. Measurement techniques for in situ stresses around underground constructions in a deep clay formation

    NASA Astrophysics Data System (ADS)

    Verstricht, J.; Areias, L.; Bastiaens, W.; Li, X. L.

    2010-06-01

    Disposal in deep underground geological formations is internationally recognized as the most viable option for the long-term management of high-level radioactive waste. In Belgium, the Boom clay formation is extensively studied in this context, in particular at the 225 m deep HADES Underground Research Facility in Mol. A cost-effective design of deep underground structures requires an accurate assessment of the in situ stresses; a good estimation of these stresses is also essential when interpreting in situ experiments regarding the hydro-mechanical behaviour of the host formation. Different measurement techniques are available to provide data on the stress evolution and other mechanical properties of the geological formation. The measurement can be direct (measurement of total pressure), or it can be an indirect technique, deriving the stress from related quantities such as strain (changes) in structural members. Most total stress measurements are performed through permanently installed sensors; also once-only measurements are performed through specific methods (e.g. pressuremeter). Direct measurement of the stress state is challenging due to the complex mechanical behaviour of the clay, and the fact that the sensor installation inevitably disturbs the original stress field. This paper describes ways to deal with these problems and presents the results obtained using different techniques at HADES.

  8. Fast in situ airborne measurement of ammonia using a mid-infrared off-axis ICOS spectrometer.

    PubMed

    Leen, J Brian; Yu, Xiao-Ying; Gupta, Manish; Baer, Douglas S; Hubbe, John M; Kluzek, Celine D; Tomlinson, Jason M; Hubbell, Mike R

    2013-09-17

    A new ammonia (NH3) analyzer was developed based on off-axis integrated cavity output spectroscopy. Its feasibility was demonstrated by making tropospheric measurements in flights aboard the Department of Energy Gulfstream-1 aircraft. The ammonia analyzer consists of an optical cell, quantum-cascade laser, gas sampling system, control and data acquisition electronics, and analysis software. The NH3 mixing ratio is determined from high-resolution absorption spectra obtained by tuning the laser wavelength over the NH3 fundamental vibration band near 9.67 μm. Excellent linearity is obtained over a wide dynamic range (0-101 ppbv) with a response rate (1/e) of 2 Hz and a precision of ±90 pptv (1σ in 1 s). Two research flights were conducted over the Yakima Valley in Washington State. In the first flight, the ammonia analyzer was used to identify signatures of livestock from local dairy farms with high vertical and spatial resolution under low wind and calm atmospheric conditions. In the second flight, the analyzer captured livestock emission signals under windy conditions. Our results demonstrate that this new ammonia spectrometer is capable of providing fast, precise, and accurate in situ observations of ammonia aboard airborne platforms to advance our understanding of atmospheric compositions and aerosol formation.

  9. Fast In Situ Airborne Measurement of Ammonia Using a Mid-Infrared Off-Axis ICOS Spectrometer

    SciTech Connect

    Leen, J. Brian; Yu, Xiao-Ying; Gupta, Manish; Baer, Douglas S.; Hubbe, John M.; Kluzek, Celine D.; Tomlinson, Jason M.; Hubbell, Mike R.

    2013-08-23

    A new ammonia (NH3) analyzer was developed based on off-axis integrated cavity output spectroscopy. Its feasibility was demonstrated by making tropospheric measurements in flights aboard the Department of Energy Gulfstream-1 aircraft. The ammonia analyzer consists of an optical cell, quantum-cascade laser, gas sampling system, control and data acquisition electronics, and analysis software. The NH3 mixing ratio is determined from high-resolution absorption spectra obtained by tuning the laser wavelength over the NH3 fundamental vibration band near 9.67 μm. Excellent linearity is obtained over a wide dynamic range (0–101 ppbv) with a response rate (1/e) of 2 Hz and a precision of ±90 pptv (1σ in 1 s). Two research flights were conducted over the Yakima Valley in Washington State. In the first flight, the ammonia analyzer was used to identify signatures of livestock from local dairy farms with high vertical and spatial resolution under low wind and calm atmospheric conditions. In the second flight, the analyzer captured livestock emission signals under windy conditions. Finally, our results demonstrate that this new ammonia spectrometer is capable of providing fast, precise, and accurate in situ observations of ammonia aboard airborne platforms to advance our understanding of atmospheric compositions and aerosol formation.

  10. Novel, in-situ Raman and fluorescence measurement techniques: Imaging using optical waveguides

    NASA Astrophysics Data System (ADS)

    Carter, Jerry Chance

    dibromostyrene. To further demonstrate the utility of in- situ spectral imaging, we have shown that small diameter (350 μm) image guides can be used for in-situ measurements of analyte transport in thin membranes. This has been applied to the measurement of H2O diffusion in Nafion™ membranes using the luminescent compound, [Ru(phen)2dppz] 2+, which is a H2O indicator.

  11. Estimation of Aerosol Direct Radiative Effects from Satellite and In Situ Measurements

    NASA Technical Reports Server (NTRS)

    Bergstrom, Robert W.; Russell, Philip B.; Schmid, Beat; Redemann, Jens; McIntosh, Dawn

    2000-01-01

    Ames researchers have combined measurements from satellite, aircraft, and the surface to estimate the effect of airborne particles (aerosols) on the solar radiation over the North Atlantic region. These aerosols (which come from both natural and pollution sources) can reflect solar radiation, causing a cooling effect that opposes the warming caused by carbon dioxide. Recently, increased attention has been paid to aerosol effects to better understand the Earth climate system.

  12. Comparison of the aerosol optical properties and size distribution retrieved by sun photometer with in situ measurements at midlatitude

    NASA Astrophysics Data System (ADS)

    Chauvigné, Aurélien; Sellegri, Karine; Hervo, Maxime; Montoux, Nadège; Freville, Patrick; Goloub, Philippe

    2016-09-01

    Aerosols influence the Earth radiative budget through scattering and absorption of solar radiation. Several methods are used to investigate aerosol properties and thus quantify their direct and indirect impacts on climate. At the Puy de Dôme station, continuous high-altitude near-surface in situ measurements and low-altitude ground-based remote sensing atmospheric column measurements give the opportunity to compare the aerosol extinction measured with both methods over a 1-year period. To our knowledge, it is the first time that such a comparison is realised with continuous measurements of a high-altitude site during a long-term period. This comparison addresses to which extent near-surface in situ measurements are representative of the whole atmospheric column, the aerosol mixing layer (ML) or the free troposphere (FT). In particular, the impact of multi-aerosol layers events detected using lidar backscatter profiles is analysed. A good correlation between in situ aerosol extinction coefficient and aerosol optical depth (AOD) measured by the Aerosol Robotic Network (AERONET) sun photometer is observed with a correlation coefficient around 0.80, indicating that the in situ measurements station is representative of the overall atmospheric column. After filtering for multilayer cases and correcting for each layer optical contribution (ML and FT), the atmospheric structure seems to be the main factor influencing the comparison between the two measurement techniques. When the site lies in the ML, the in situ extinction represents 45 % of the sun photometer ML extinction while when the site lies within the FT, the in situ extinction is more than 2 times higher than the FT sun photometer extinction. Moreover, the assumption of a decreasing linear vertical aerosol profile in the whole atmosphere has been tested, significantly improving the instrumental agreement. Remote sensing retrievals of the aerosol particle size distributions (PSDs) from the sun photometer

  13. Disparity pattern-based autostereoscopic 3D metrology system for in situ measurement of microstructured surfaces.

    PubMed

    Li, Da; Cheung, Chi Fai; Ren, MingJun; Whitehouse, David; Zhao, Xing

    2015-11-15

    This paper presents a disparity pattern-based autostereoscopic (DPA) 3D metrology system that makes use of a microlens array to capture raw 3D information of the measured surface in a single snapshot through a CCD camera. Hence, a 3D digital model of the target surface with the measuring data is generated through a system-associated direct extraction of disparity information (DEDI) method. The DEDI method is highly efficient for performing the direct 3D mapping of the target surface based on tomography-like operation upon every depth plane with the defocused information excluded. Precise measurement results are provided through an error-elimination process based on statistical analysis. Experimental results show that the proposed DPA 3D metrology system is capable of measuring 3D microstructured surfaces with submicrometer measuring repeatability for high precision and in situ measurement of microstructured surfaces.

  14. ExoCube: In-Situ Measurement of Composition in the Exosphere, Thermosphere and Topside Ionosphere

    NASA Astrophysics Data System (ADS)

    Noto, J.; Waldrop, L.; Paschalidis, N.; Taylor, C.; Gardner, D. D.; Jones, S.; Rodriguez, M.; Nossal, S. M.; Mierkiewicz, E. J.; Puig-Suari, J.; Kerr, R.

    2014-12-01

    Quantification of neutral species densities in the upper thermosphere and lower exosphere remains elusive despite the analytical theories established by the pioneers of Aeronomy roughly fifty years ago, despite the evident requirements of Space Weather modeling, and despite the pragmatic reality of manned and unmanned spacecraft exploitation of the region. In fact, [O], [He] and [N2] have not been measured in-situ in the upper atmosphere since the era of DE-2, and then for only 18 months from 1981-1983 (near solar maximum). Prior to that, the Atmospheric Explorer program (AE-A launched in 1963, AE-E ended in 1980) provided the neutral density information upon which the MSIS model is largely based. No instrument has measured [H] in-situ, which is instead derived in MSIS by solution of the proton continuity equation.The ExoCube satellite provides a long-overdue benchmark for the densities of significant neutral and ionized species in the upper atmosphere, on a global scale, for the Space Weather and Aeronomy communities. These will be the first in-situ global neutral density data since DE-2, including the first direct measurements of [H] using a mass spectrometer technique. Since roughly half of the total electron column content (TEC) arises from photoionization of H, reliable knowledge of exospheric [H] is a crucial requirement of realistic Space Weather modeling of TEC. To insure that this project has enduring impact beyond the projected two-year duration of the satellite mission, experimental interaction with ground-based ISR and optical facilities is integrated. The simultaneous collection of ion and neutral densities will facilitate the use of ExoCube data for studies of charge exchange processes. Overpasses with observatories will enable ExoCube measurements to be used as a constraint for retrieval of density information from forward modeling of ground-based observations. Presented here will be the first post-launch mission status and operations.

  15. Feasibility of an in situ measurement device for bubble size and distribution

    PubMed Central

    Maciejak, Walter; Darnell, Branson; Lester, Michael; Pollack, Michael

    2007-01-01

    The feasibility of in situ measurement device for bubble size and distribution was explored. A novel in situ probe measurement system, the EnviroCam™, was developed. Where possible, this probe incorporated strengths, and minimized weaknesses of historical and currently available real-time measurement methods for bubbles. The system was based on a digital, high-speed, high resolution, modular camera system, attached to a stainless steel shroud, compatible with standard Ingold ports on fermenters. Still frames and/or video were produced, capturing bubbles passing through the notch of the shroud. An LED light source was integral with the shroud. Bubbles were analyzed using customized commercially available image analysis software and standard statistical methods. Using this system, bubble sizes were measured as a function of various operating parameters (e.g., agitation rate, aeration rate) and as a function of media properties (e.g., viscosity, antifoam, cottonseed flour, and microbial/animal cell broths) to demonstrate system performance and its limitations. For selected conditions, mean bubble size changes qualitatively compared favorably with published relationships. Current instrument measurement capabilities were limited primarily to clear solutions that did not contain large numbers of overlapping bubbles. PMID:17566786

  16. Advanced Soil Moisture Network Technologies; Developments in Collecting in situ Measurements for Remote Sensing Missions

    NASA Astrophysics Data System (ADS)

    Moghaddam, M.; Silva, A. R. D.; Akbar, R.; Clewley, D.

    2015-12-01

    The Soil moisture Sensing Controller And oPtimal Estimator (SoilSCAPE) wireless sensor network has been developed to support Calibration and Validation activities (Cal/Val) for large scale soil moisture remote sensing missions (SMAP and AirMOSS). The technology developed here also readily supports small scale hydrological studies by providing sub-kilometer widespread soil moisture observations. An extensive collection of semi-sparse sensor clusters deployed throughout north-central California and southern Arizona provide near real time soil moisture measurements. Such a wireless network architecture, compared to conventional single points measurement profiles, allows for significant and expanded soil moisture sampling. The work presented here aims at discussing and highlighting novel and new technology developments which increase in situ soil moisture measurements' accuracy, reliability, and robustness with reduced data delivery latency. High efficiency and low maintenance custom hardware have been developed and in-field performance has been demonstrated for a period of three years. The SoilSCAPE technology incorporates (a) intelligent sensing to prevent erroneous measurement reporting, (b) on-board short term memory for data redundancy, (c) adaptive scheduling and sampling capabilities to enhance energy efficiency. A rapid streamlined data delivery architecture openly provides distribution of in situ measurements to SMAP and AirMOSS cal/val activities and other interested parties.

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

    NASA Astrophysics Data System (ADS)

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

    2015-12-01

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

  18. Rat airway morphometry measured from in situ MRI-based geometric models

    PubMed Central

    Oakes, Jessica M.; Scadeng, Miriam; Breen, Ellen C.; Marsden, Alison L.

    2012-01-01

    Rodents have been widely used to study the environmental or therapeutic impact of inhaled particles. Knowledge of airway morphometry is essential in assessing geometric influence on aerosol deposition and in developing accurate lung models of aerosol transport. Previous morphometric studies of the rat lung performed ex situ provided high-resolution measurements (50–125 μm). However, it is unclear how the overall geometry of these casts might have differed from the natural in situ appearance. In this study, four male Wistar rat (268 ± 14 g) lungs were filled sequentially with perfluorocarbon and phosphate-buffered saline before being imaged in situ in a 7-T magnetic resonance (MR) scanner at a resolution of 0.2 × 0.2 × 0.27 mm. Airway length, diameter, gravitational, bifurcation, and rotational angles were measured for the first four airway generations from 3D geometric models built from the MR images. Minor interanimal variability [expressed by the relative standard deviation RSD (=SD/mean)] was found for length (0.18 ± 0.07), diameter (0.15 ± 0.15), and gravitational angle (0.12 ± 0.06). One rat model was extended to 16 airway generations. Organization of the airways using a diameter-defined Strahler ordering method resulted in lower interorder variability than conventional generation-based grouping for both diameter (RSD = 0.12 vs. 0.42) and length (0.16 vs. 0.67). Gravitational and rotational angles averaged 82.9 ± 37.9° and 53.6 ± 24.1°, respectively. Finally, the major daughter branch bifurcated at a smaller angle (19.3 ± 14.6°) than the minor branch (60.5 ± 19.4°). These data represent the most comprehensive set of rodent in situ measurements to date and can be used readily in computational studies of lung function and aerosol exposure. PMID:22461437

  19. Return glider radiosonde for in situ upper-air research measurements

    NASA Astrophysics Data System (ADS)

    Kräuchi, Andreas; Philipona, Rolf

    2016-06-01

    Upper-air balloon soundings for weather predictions have been made since the beginning of the 20th century. New radiosonde instruments for in situ humidity-, radiation- and gas-profile measurements in the troposphere and the lower stratosphere, were introduced in recent years for atmospheric research and climate monitoring, but such instruments are often expensive and it is desired they be reused on multiple flights. Recovering instruments that freely descend with parachutes is time consuming, sometimes difficult and even dangerous. Here, we introduce the return glider radiosonde (RGR), which enables flying and retrieving valuable in situ upper-air instruments. The RGR is lifted with weather balloons similar to traditional radiosondes to a preset altitude, at which time a release mechanism cuts the tether string, and a built-in autopilot flies the glider autonomously back to the launch site or a desired preprogrammed location. Once the RGR reaches the landing coordinates it circles down and releases a parachute 100 m above ground for landing. The motivation for this project was to measure radiation profiles throughout the atmosphere with the same instrument multiple times and with a rapid turn-around time. The paper describes technical aspects of the return glider radiosonde and the built-in radiation instruments and shows test flights up to 24 km altitude that are analyzed in terms of flight performance and maximal distances covered. Several successive flights measuring radiation profiles demonstrate the reliability and the operational readiness of the RGR, allowing new ways for atmospheric in situ research and monitoring with payloads up to several kg depending on the specific size of the glider.

  20. A load-lock compatible system for in situ electrical resistivity measurements during thin film growth.

    PubMed

    Colin, J J; Diot, Y; Guerin, Ph; Lamongie, B; Berneau, F; Michel, A; Jaouen, C; Abadias, G

    2016-02-01

    An experimental setup designed for in situ electrical resistance measurement during thin film growth is described. The custom-built sample holder with a four-point probe arrangement can be loaded into a high-vacuum magnetron sputter-deposition chamber through a load-lock transfer system, allowing measurements on series of samples without venting the main chamber. Electrical contact is ensured with circular copper tracks inserted in a Teflon plate on a mounting holder station inside the deposition chamber. This configuration creates the possibility to measure thickness-dependent electrical resistance changes with sub-monolayer resolution and is compatible with use of sample rotation during growth. Examples are presented for metallic films with high adatom mobility growing in a Volmer-Weber mode (Ag and Pd) as well as for refractory metal (Mo) with low adatom mobility. Evidence for an amorphous-to-crystalline phase transition at a film thickness of 2.6 nm is reported during growth of Mo on an amorphous Si underlayer, supporting previous findings based on in situ wafer curvature measurements.

  1. In situ strain and temperature measurement and modelling during arc welding

    DOE PAGES

    Chen, Jian; Yu, Xinghua; Miller, Roger G.; ...

    2014-12-26

    In this study, experiments and numerical models were applied to investigate the thermal and mechanical behaviours of materials adjacent to the weld pool during arc welding. In the experiment, a new high temperature strain measurement technique based on digital image correlation (DIC) was developed and applied to measure the in situ strain evolution. In contrast to the conventional DIC method that is vulnerable to the high temperature and intense arc light involved in fusion welding processes, the new technique utilised a special surface preparation method to produce high temperature sustaining speckle patterns required by the DIC algorithm as well asmore » a unique optical illumination and filtering system to suppress the influence of the intense arc light. These efforts made it possible for the first time to measure in situ the strain field 1 mm away from the fusion line. The temperature evolution in the weld and the adjacent regions was simultaneously monitored by an infrared camera. Finally and additionally, a thermal–mechanical finite element model was applied to substantiate the experimental measurement.« less

  2. A load-lock compatible system for in situ electrical resistivity measurements during thin film growth

    NASA Astrophysics Data System (ADS)

    Colin, J. J.; Diot, Y.; Guerin, Ph.; Lamongie, B.; Berneau, F.; Michel, A.; Jaouen, C.; Abadias, G.

    2016-02-01

    An experimental setup designed for in situ electrical resistance measurement during thin film growth is described. The custom-built sample holder with a four-point probe arrangement can be loaded into a high-vacuum magnetron sputter-deposition chamber through a load-lock transfer system, allowing measurements on series of samples without venting the main chamber. Electrical contact is ensured with circular copper tracks inserted in a Teflon plate on a mounting holder station inside the deposition chamber. This configuration creates the possibility to measure thickness-dependent electrical resistance changes with sub-monolayer resolution and is compatible with use of sample rotation during growth. Examples are presented for metallic films with high adatom mobility growing in a Volmer-Weber mode (Ag and Pd) as well as for refractory metal (Mo) with low adatom mobility. Evidence for an amorphous-to-crystalline phase transition at a film thickness of 2.6 nm is reported during growth of Mo on an amorphous Si underlayer, supporting previous findings based on in situ wafer curvature measurements.

  3. In situ strain and temperature measurement and modelling during arc welding

    SciTech Connect

    Chen, Jian; Yu, Xinghua; Miller, Roger G.; Feng, Zhili

    2014-12-26

    In this study, experiments and numerical models were applied to investigate the thermal and mechanical behaviours of materials adjacent to the weld pool during arc welding. In the experiment, a new high temperature strain measurement technique based on digital image correlation (DIC) was developed and applied to measure the in situ strain evolution. In contrast to the conventional DIC method that is vulnerable to the high temperature and intense arc light involved in fusion welding processes, the new technique utilised a special surface preparation method to produce high temperature sustaining speckle patterns required by the DIC algorithm as well as a unique optical illumination and filtering system to suppress the influence of the intense arc light. These efforts made it possible for the first time to measure in situ the strain field 1 mm away from the fusion line. The temperature evolution in the weld and the adjacent regions was simultaneously monitored by an infrared camera. Finally and additionally, a thermal–mechanical finite element model was applied to substantiate the experimental measurement.

  4. In situ methods for measuring thermal properties and heat flux on planetary bodies

    PubMed Central

    Kömle, Norbert I.; Hütter, Erika S.; Macher, Wolfgang; Kaufmann, Erika; Kargl, Günter; Knollenberg, Jörg; Grott, Matthias; Spohn, Tilman; Wawrzaszek, Roman; Banaszkiewicz, Marek; Seweryn, Karoly; Hagermann, Axel

    2011-01-01

    The thermo-mechanical properties of planetary surface and subsurface layers control to a high extent in which way a body interacts with its environment, in particular how it responds to solar irradiation and how it interacts with a potentially existing atmosphere. Furthermore, if the natural temperature profile over a certain depth can be measured in situ, this gives important information about the heat flux from the interior and thus about the thermal evolution of the body. Therefore, in most of the recent and planned planetary lander missions experiment packages for determining thermo-mechanical properties are part of the payload. Examples are the experiment MUPUS on Rosetta's comet lander Philae, the TECP instrument aboard NASA's Mars polar lander Phoenix, and the mole-type instrument HP3 currently developed for use on upcoming lunar and Mars missions. In this review we describe several methods applied for measuring thermal conductivity and heat flux and discuss the particular difficulties faced when these properties have to be measured in a low pressure and low temperature environment. We point out the abilities and disadvantages of the different instruments and outline the evaluation procedures necessary to extract reliable thermal conductivity and heat flux data from in situ measurements. PMID:21760643

  5. CO2 variability from in situ and vertical column measurements in Mexico City

    NASA Astrophysics Data System (ADS)

    Baylon, J. L.; Grutter, M.; Stremme, W.; Bezanilla, A.; Plaza, E.

    2014-12-01

    UNAM started a program to measure, among many other atmospheric parameters, greenhouse gas concentrations at six stations in the Mexican territory as part of the "Red Universitaria de Observatorios Atmosfericos", RUOA (www.ruoa.unam.mx). In this work we present recent time series of CO2 measured at the station located in the university campus in Mexico City, and compare them to total vertical columns of this gas measured at the same location. In situ measurements are continuously carried out with a cavity ring-down spectrometer (Picarro Inc., G2401) since July 2014 and the columns are retrieved from solar absorption measurements taken with a Fourier transform infrared spectrometer (Bruker, Vertex 80) when conditions allow. The retrieval method is described and results of the comparison of both techniques and a detailed analysis of the variability of this important greenhouse gas is presented. Simultaneous surface and column CO2 data are useful to constrain models and estimate emissions.

  6. Development of a Flight Instrument for in situ Measurements of Ethane and Methane

    NASA Astrophysics Data System (ADS)

    Wilkerson, J. P.; Sayres, D. S.; Anderson, J. G.

    2015-12-01

    Methane emissions data for natural gas and oil fields have high uncertainty. Better quantifying these emissions is crucial to establish an accurate methane budget for the United States. One obstacle is that these emissions often occur in areas near livestock facilities where biogenic methane abounds. Measuring ethane, which has no biogenic source, along with methane can tease these sources apart. However, ethane is typically measured by taking whole-air samples. This tactic has lower spatial resolution than making in situ measurements and requires the measurer to anticipate the location of emission plumes. This leaves unexpected plumes uncharacterized. Using Re-injection Mirror Integrated Cavity Output Spectroscopy (RIM-ICOS), we can measure both methane and ethane in flight, allowing us to establish more accurate fugitive emissions data that can more readily distinguish between different sources of this greenhouse gas.

  7. CBSIT 2009: Airborne Validation of Envisat Radar Altimetry and In Situ Ice Camp Measurements Over Arctic Sea Ice

    NASA Technical Reports Server (NTRS)

    Connor, Laurence; Farrell, Sinead; McAdoo, David; Krabill, William; Laxon, Seymour; Richter-Menge, Jacqueline; Markus, Thorsten

    2010-01-01

    with (1) Envisat RA-2 returns retracked optimally for sea ice and (2) in situ measurements of sea ice thickness and snow depth gathered from ice camp surveys. Particular attention is given to lead identification and classification using the continuous photo-imaging system along the Envisat underflight as well as the performance of the snow radar over the ice camp survey lines.

  8. Validation of the large-scale Lagrangian cirrus model CLaMS-Ice by in-situ measurements

    NASA Astrophysics Data System (ADS)

    Costa, Anja; Rolf, Christian; Grooß, Jens-Uwe; Afchine, Armin; Spelten, Nicole; Dreiling, Volker; Zöger, Martin; Krämer, Martina

    2015-04-01

    Cirrus clouds are an element of uncertainty in the climate system and have received increasing attention since the last IPCC reports. The interaction of varying freezing meachanisms, sedimentation rates, temperature and updraft velocity fluctuations and other factors that lead to the formation of those clouds is still not fully understood. During the ML-Cirrus campaign 2014 (Germany), the new cirrus cloud model CLaMS-Ice (see Rolf et al., EGU 2015) has been used for flight planning to direct the research aircraft HALO into interesting cirrus cloud regions. Now, after the campaign, we use our in-situ aircraft measurements to validate and improve this model - with the long-term goal to enable it to simulate cirrus cloud cover globally, with reasonable computing times and sufficient accuracy. CLaMS-Ice consists of a two-moment bulk model established by Spichtinger and Gierens (2009a, 2009b), which simulates cirrus clouds along trajectories that the Lagrangian model CLaMS (McKenna et al., 2002 and Konopka et al. 2007) derived from ECMWF data. The model output covers temperature, pressure, relative humidity, ice water content (IWC), and ice crystal numbers (Nice). These parameters were measured on board of HALO by the following instruments: temperature and pressure by BAHAMAS, total and gas phase water by the hygrometers FISH and SHARC (see Meyer et al 2014, submitted to ACP), and Nice as well as ice crystal size distributions by the cloud spectrometer NIXE-CAPS (see also Krämer et al., EGU 2015). Comparisons of the model results with the measurements yield that cirrus clouds can be successfully simulated by CLaMS-Ice. However, there are sections in which the model's relative humidity and Nice deviate considerably from the measured values. This can be traced back to e.g. the initialization of total water from ECMWF data. The simulations are therefore reinitiated with the total water content measured by FISH. Other possible sources of uncertainties are investigated, as

  9. Rapid In-Situ Measurement of Gamma Activity in Soil for Environmental Assessment

    NASA Astrophysics Data System (ADS)

    Honeycutt, T. K.

    2003-12-01

    In-situ measurements of gamma radiation in soil are used as a rapid, low-cost, non-intrusive alternative to conventional sampling and analysis methods in the preliminary assessment of environmental impacts to watersheds at the Savannah River Site (SRS). The method resolves the ambient gamma-radiation field near ground surface into background and residual components and provides radionuclide-specific soil activity determination. The efficacy of the method has been evaluated and compares favorably with conventional gamma-PHA soil analyses and aerial survey data. The method has garnered regulatory approval and is being successfully deployed to evaluate the impact of Cs-137 contamination from CERCLA sites.

  10. In situ measurement of osmium concentrations in iron meteorites by resonance ionization of sputtered atoms

    NASA Astrophysics Data System (ADS)

    Blum, J.; Pellin, M. J.; Calaway, W. F.; Young, C. E.; Gruen, D. M.; Hutcheon, I. D.; Wasserburg, G. J.

    1990-03-01

    Resonance ionization of sputtered atoms followed by time-of-flight mass spectrometry was used for in situ quantitative measurement of Os with a spatial resolution of about 70 microns. A linear correlation between Os(+) signal intensity and the known Os concentration was observed over a range of nearly 10,000 in Os concentration with an accuracy of about + or - 10 percent, a minimum detection limit of 7 parts per billion atomic, and a useful yield of 1 percent. Resonance ionization of sputtered atoms samples the dominant neutral-fraction of sputtered atoms and utilizes multiphoton resonance ionization to achieve high sensitivity and to eliminate atomic and molecular interferences.

  11. In situ measurements constraining the role of sulphate aerosols in mid-latitude ozone depletion

    NASA Technical Reports Server (NTRS)

    Fahey, D. W.; Kawa, S. R.; Woodbridge, E. L.; Tin, P.; Wilson, J. C.; Jonsson, H. H.; Dye, J. E.; Baumgardner, D.; Borrmann, S.; Toohey, D. W.

    1993-01-01

    In situ measurements of stratospheric sulphate aerosol, reactive nitrogen and chlorine concentrations at middle latitudes confirm the importance of aerosol surface reactions that convert active nitrogen to a less active, reservoir form. This makes mid-latitude stratospheric ozone less vulnerable to active nitrogen and more vulnerable to chlorine species. The effect of aerosol reactions on active nitrogen depends on gas phase reaction rates, so that increases in aerosol concentration following volcanic eruptions will have only a limited effect on ozone depletion at these latitudes.

  12. MEASURING THE PLASTIC RESPONSE IN POLYCRSYTALLINE MATERIALS USING IN-SITU X-RAY DIFFRACTION

    SciTech Connect

    Hawreliak, J; Butterfield, M; El-Dasher, B; McNaney, J; Lorenzana, H

    2008-10-01

    The insight provided by ultra-fast lattice level measurements during high strain rate high pressure experiments is key to understanding kinetic material properties like plasticity. In-situ x-ray diffraction provides a diagnostic technique which can be used to study the governing physical phenomena of plasticity at the relevant time and spatial scale. Here we discuss the recent development of a geometry capable of investigating plasticity in polycrystalline foils. We also present some preliminary data of investigations into shock compressed rolled copper foils.

  13. F4TCNQ-Induced Exciton Quenching Studied by Using in-situ Photoluminescence Measurements

    NASA Astrophysics Data System (ADS)

    Zhu, Jian; Lu, Min; Wu, Bo; Hou, Xiao-Yuan

    2012-09-01

    The role of F4TCNQ as an exciton quenching material in thin organic light-emitting films is investigated by means of in situ photoluminescence measurements. C60 was used as another quenching material in the experiment for comparison, with Alq3 as a common organic light-emitting material. The effect of the growth sequence of the materials on quenching was also examined. It is found that the radius of Förster energy transfer between F4TCNQ and Alq3 is close to 0 nm and Dexter energy transfer dominates in the quenching process.

  14. In Situ, Time-Resolved Accelerator Grid Erosion Measurements in the NSTAR 8000 Hour Ion Engine Wear Test

    NASA Technical Reports Server (NTRS)

    Sovey, J.

    1997-01-01

    Time-resolved, in situ measurements of the charge exchange ion erosion pattern on the downstream face of the accelerator grid have been made during an ongoin wear test of the NSTAR 30 cm ion thruster.

  15. Airborne In-Situ Measurements of Formaldehyde over California: First Results from the Compact Formaldehyde Fluorescence Experiment (COFFEE) Instrument

    NASA Technical Reports Server (NTRS)

    Marrero, Josette; St. Clair, Jason; Yates, Emma L.; Gore, Warren; Swanson, Andrew K.; Iraci, Laura T.; Hanisco, Thomas F.

    2016-01-01

    Formaldehyde (HCHO) is one of the most abundant oxygenated volatile organic compounds (VOCs) in the atmosphere, playing a role multiple atmospheric processes. Measurements of HCHO can be used to help quantify convective transport, the abundance of VOCs, and ozone production in urban environments. The Compact Formaldehyde FluorescencE Experiment (COFFEE) instrument uses Non-Resonant Laser Induced Fluorescence (NR-LIF) to detect trace concentrations of HCHO as part of the Alpha Jet Atmospheric eXperiment (AJAX) payload. Developed at NASA GSFC, COFFEE is a small, low maintenance instrument with a sensitivity of 100 pptv and a quick response time (1 sec). The COFFEE instrument has been customized to fit in an external wing pod on the Alpha Jet aircraft based at NASA ARC. The instrument can operate over a broad range of altitudes, from boundary layer to lower stratosphere, making it well suited for the Alpha Jet, which can access altitudes from the surface up to 40,000 ft. Results of the first COFFEE science flights preformed over the California's Central Valley will be presented. Boundary layer measurements and vertical profiles in the tropospheric column will both be included. This region is of particular interest, due to its elevated levels of HCHO, revealed in satellite images, as well as its high ozone concentrations. In addition to HCHO, the AJAX payload includes measurements of atmospheric ozone, methane, and carbon dioxide. Formaldehyde is one of the few urban pollutants that can be measured from space. Plans to compare in-situ COFFEE data with satellite-based HCHO observations such as those from OMI (Aura) and OMPS (SuomiNPP) will also be presented.

  16. Airborne In-Situ Measurements of Formaldehyde Over California: First Results from the Compact Formaldehyde Fluorescence Experiment (COFFEE) Instrument

    NASA Technical Reports Server (NTRS)

    Marrero, Josette Elizabeth; Saint Clair, Jason; Yates, Emma L.; Gore, Warren; Swanson, Andrew K.; Iraci, Laura T.; Hanisco, Thomas F.

    2016-01-01

    Formaldehyde (HCHO) is one of the most abundant oxygenated volatile organic compounds (VOCs) in the atmosphere, playing a role multiple atmospheric processes. Measurements of HCHO can be used to help quantify convective transport, the abundance of VOCs, and ozone production in urban environments. The Compact Formaldehyde FluorescencE Experiment (COFFEE) instrument uses Non-Resonant Laser Induced Fluorescence (NR-LIF) to detect trace concentrations of HCHO as part of the Alpha Jet Atmospheric eXperiment (AJAX) payload. Developed at NASA GSFC, COFFEE is a small, low maintenance instrument with a sensitivity of 100 pptv and a quick response time (1 sec). The COFFEE instrument has been customized to fit in an external wing pod on the Alpha Jet aircraft based at NASA ARC. The instrument can operate over a broad range of altitudes, from boundary layer to lower stratosphere, making it well suited for the Alpha Jet, which can access altitudes from the surface up to 40,000 ft. Results of the first COFFEE science flights preformed over the California's Central Valley will be presented. Boundary layer measurements and vertical profiles in the tropospheric column will both be included. This region is of particular interest, due to its elevated levels of HCHO, revealed in satellite images, as well as its high ozone concentrations. In addition to HCHO, the AJAX payload includes measurements of atmospheric ozone, methane, and carbon dioxide. Formaldehyde is one of the few urban pollutants that can be measured from space. Plans to compare in-situ COFFEE data with satellite-based HCHO observations such as those from OMI (Aura) and OMPS (SuomiNPP) will also be presented.

  17. 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.

  18. 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.

  19. Testing coordinate measuring arms with a geometric feature-based gauge: in situ field trials

    NASA Astrophysics Data System (ADS)

    Cuesta, E.; Alvarez, B. J.; Patiño, H.; Telenti, A.; Barreiro, J.

    2016-05-01

    This work describes in detail the definition of a procedure for calibrating and evaluating coordinate measuring arms (AACMMs or CMAs). CMAs are portable coordinate measuring machines that have been widely accepted in industry despite their sensitivity to the skill and experience of the operator in charge of the inspection task. The procedure proposed here is based on the use of a dimensional gauge that incorporates multiple geometric features, specifically designed for evaluating the measuring technique when CMAs are used, at company facilities (workshops or laboratories) and by the usual operators who handle these devices in their daily work. After establishing the procedure and manufacturing the feature-based gauge, the research project was complemented with diverse in situ field tests performed with the collaboration of companies that use these devices in their inspection tasks. Some of the results are presented here, not only comparing different operators but also comparing different companies. The knowledge extracted from these experiments has allowed the procedure to be validated, the defects of the methodologies currently used for in situ inspections to be detected, and substantial improvements for increasing the reliability of these portable instruments to be proposed.

  20. Image correlation method for measuring flow and diameter changes in contracting mesenteric microlymphatics in situ

    NASA Astrophysics Data System (ADS)

    Dixon, J. Brandon; Cote, Gerard; Gashev, Anatoly; Greiner, Steven; Moore, James; Zawieja, David

    2006-02-01

    Collecting microlymphatics play a vital role in promoting lymph flow from the initial lymphatics in the interstitial spaces to the large transport lymph ducts. In most tissues, the primary mechanism for producing this flow is the spontaneous contractions of the lymphatic wall. Individual units, known as lymphangion, are separated by valves that help prevent backflow when the vessel contracts, thus promoting flow through the lymphatic network. Lymphatic contractile activity is inhibited by flow in isolated lymphatics, however there are virtually no in situ measurements of lymph flow in these vessels. One of the difficulties associated with obtaining such measurements is the time consuming methods of manual particle tracking used previously by our group. Using an in situ preparation with mesenteric microlymphatics (~ 100 μm in diameter) and a high speed imaging system (500 fps), we have developed an image correlation method to measure lymphatic flow with a standard error of prediction of 0.3 mm/sec when compared with manual particle tracking.

  1. Time-Resolved In Situ Measurements During Rapid Alloy Solidification: Experimental Insight for Additive Manufacturing

    DOE PAGES

    McKeown, Joseph T.; Zweiacker, Kai; Liu, Can; ...

    2016-01-27

    In research and industrial environments, additive manufacturing (AM) of metals and alloys is becoming a pervasive technology, though significant challenges remain before widespread implementation of AM can be realized. In situ investigations of rapid alloy solidification with high spatial and temporal resolutions can provide unique experimental insight into microstructure evolution and kinetics that are relevant for AM processing. Hypoeutectic thin-film Al–Cu and Al–Si alloys were investigated using dynamic transmission electron microscopy to monitor pulsed-laser-induced rapid solidification across microsecond timescales. Solid–liquid interface velocities measured from time-resolved images revealed accelerating solidification fronts in both alloys. We observed microstructure evolution, solidification product, andmore » presence of a morphological instability at the solid–liquid interface in the Al–4 at.%Cu alloy are related to the measured interface velocities and small differences in composition that affect the thermophysical properties of the alloys. These time-resolved in situ measurements can inform and validate predictive modeling efforts for AM.« less

  2. Time-Resolved In Situ Measurements During Rapid Alloy Solidification: Experimental Insight for Additive Manufacturing

    SciTech Connect

    McKeown, Joseph T.; Zweiacker, Kai; Liu, Can; Coughlin, Daniel R.; Clarke, Amy J.; Baldwin, J. Kevin; Gibbs, John W.; Roehling, John D.; Imhoff, Seth D.; Gibbs, Paul J.; Tourret, Damien; Wiezorek, Jörg M. K.; Campbell, Geoffrey H.

    2016-01-27

    In research and industrial environments, additive manufacturing (AM) of metals and alloys is becoming a pervasive technology, though significant challenges remain before widespread implementation of AM can be realized. In situ investigations of rapid alloy solidification with high spatial and temporal resolutions can provide unique experimental insight into microstructure evolution and kinetics that are relevant for AM processing. Hypoeutectic thin-film Al–Cu and Al–Si alloys were investigated using dynamic transmission electron microscopy to monitor pulsed-laser-induced rapid solidification across microsecond timescales. Solid–liquid interface velocities measured from time-resolved images revealed accelerating solidification fronts in both alloys. We observed microstructure evolution, solidification product, and presence of a morphological instability at the solid–liquid interface in the Al–4 at.%Cu alloy are related to the measured interface velocities and small differences in composition that affect the thermophysical properties of the alloys. These time-resolved in situ measurements can inform and validate predictive modeling efforts for AM.

  3. Monitoring the Eyjafjöll volcanic plume using OPGC platforms : remote sensing and in-situ measurements

    NASA Astrophysics Data System (ADS)

    Labazuy, Philippe; Gouhier, Mathieu; Hervo, Maxime; Freville, Patrick; Quehennen, Boris; Donnadieu, Frank; Guehenneux, Yannick; Cacault, Philippe; Colomb, Aurélie; Gayet, Jean-François; Pichon, Jean-Marc; Rivet, Sandrine; Schwarzenböck, Alfons; Sellegri, Karine

    2010-05-01

    optical, chemical and microphysical properties of aerosols. A few days after the volcanic plume was observed from the Lidar, concentrations of supermicronic particles significantly increased, well correlated with SO2 (22-27 April). In addition, from April 19 to April 22, the French research aircraft ATR42, equipped with microphysical probes FSSP100, FSSP300, 2D and PCASP100X performed 4 scientific flights above France, in order to quantify the volcanic ash plumes. In-situ measurements for a flight between Rouen and Toulouse on April 22nd passing over Clermont-Ferrand are presented here.

  4. Airborne passive remote sensing of large-scale methane emissions from oil fields in California's San Joaquin Valley and validation by airborne in-situ measurements - Initial results from COMEX

    NASA Astrophysics Data System (ADS)

    Gerilowski, Konstantin; Krautwurst, Sven; Kolyer, Richard W.; Thompson, David R.; Jonsson, Haflidi; Krings, Thomas; Horstjann, Markus; Leifer, Ira; Eastwood, Michael; Green, Robert O.; Vigil, Sam; Schüttemeyer, Dirk; Fladeland, Matthew; Burrows, John P.; Bovensmann, Heinrich

    2015-04-01

    On several flights performed over the Kern River, Kern Front, and Poso Creek Oil Fields in California between June 3 and September 4, 2014, in the framework of the CO2 and MEthane Experiment (COMEX) - a NASA and ESA funded campaign in support of the HyspIRI and CarbonSat mission definition activities - the Methane Airborne MAPper (MAMAP) remote sensing instrument (operated by the University of Bremen in cooperation with the German Research Centre for Geosciences - GFZ) detected large-scale, high-concentration, methane plumes. MAMAP was installed for the flights aboard the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft, together with a Picarro fast in-situ greenhouse gas (GHG) analyzer (operated by the NASA Ames Research Center, ARC), a 5-hole turbulence probe and an atmospheric measurement package (operated by CIRPAS), measuring aerosols, temperature, dew-point, and other atmospheric parameters. Some of the flights were accompanied by the next generation of the Airborne Visible InfraRed Imaging Spectrometer (AVIRIS-NG), operated by the Jet Propulsion Laboratory (JPL), California Institute of Technology, installed aboard a second Twin Otter aircraft (operated by Twin Otter International). Data collected with the in-situ GHG analyzer were used for validation of the MAMAP and AVIRIS-NG remotely sensed data. The in-situ measurements were acquired in vertical cross sections of the discovered plumes at fixed distances downwind of the sources. Emission rates are estimated from both the remote and in-situ data using wind information from the turbulence probe together with ground-based wind data from the nearby airport. Remote sensing and in-situ data as well as initial flux estimates for selected flights will be presented.

  5. Remote sensing of large scale methane emission sources with the Methane Airborne MAPper (MAMAP) instrument over the Kern River and Kern Front Oil fields and validation through airborne in-situ measurements - Initial results from COMEX

    NASA Astrophysics Data System (ADS)

    Gerilowski, K.; Krautwurst, S.; Kolyer, R.; Jonsson, H.; Krings, T.; Horstjann, M.; Leifer, I.; Schuettemeyer, D.; Fladeland, M. M.; Burrows, J. P.; Bovensmann, H.

    2014-12-01

    During three flights performed with the MAMAP (Methane Airborne MAPper) airborne remote sensing instrument in the framework of the CO2 and MEthane Experiment (COMEX) - a NASA and ESA funded campaign in support of HyspIRI and CarbonSat mission definition activities - large scale methane plumes were detected over the Kern River and Kern Front Oil fields in the period between June 3 and 13, 2014. MAMAP was installed for these flights aboard of the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft, together with a Picarro fast in-situ greenhouse gas (GHG) analyzer (operate by the Ames Research Center, ARC), a 5 hole turbulence probe as well as a atmospheric measurement package (operated by CIRPAS), measuring aerosols, temperature, dew-point and other atmospheric parameters. Data collected with the in-situ GHG analyzer will be used for validation of MAMAP remotely sensed data by acquiring vertical cross sections of the discovered plumes at a fixed downwind distance. Precise airborne wind information from the turbulence probe together with ground based wind data from the nearby airport will be used to estimate emission rates from the remote sensed and in-situ measured data. Remote sensed and in-situ data as well as initial flux estimates for the three flights will be presented.

  6. In situ roughness measurements for the solar cell industry using an atomic force microscope.

    PubMed

    González-Jorge, Higinio; Alvarez-Valado, Victor; Valencia, Jose Luis; Torres, Soledad

    2010-01-01

    Areal roughness parameters always need to be under control in the thin film solar cell industry because of their close relationship with the electrical efficiency of the cells. In this work, these parameters are evaluated for measurements carried out in a typical fabrication area for this industry. Measurements are made using a portable atomic force microscope on the CNC diamond cutting machine where an initial sample of transparent conductive oxide is cut into four pieces. The method is validated by making a comparison between the parameters obtained in this process and in the laboratory under optimal conditions. Areal roughness parameters and Fourier Spectral Analysis of the data show good compatibility and open the possibility to use this type of measurement instrument to perform in situ quality control. This procedure gives a sample for evaluation without destroying any of the transparent conductive oxide; in this way 100% of the production can be tested, so improving the measurement time and rate of production.

  7. 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.

  8. In situ calibrated defocusing PTV for wall-bounded measurement volumes

    NASA Astrophysics Data System (ADS)

    Fuchs, T.; Hain, R.; Kähler, C. J.

    2016-08-01

    In many situations, 3D velocity measurements in thin (∼1 mm) but wide (∼100  ×  100 mm2) flow channels is an important task. To resolve the in-plane and out-of-plane velocity gradients properly, a precise calibration is required, since 3D measurement approaches rely strongly on the accuracy of the calibration procedure. It is likely that calibration targets do not fit domains with small depths, due to their size. Furthermore, in fields where such measurements are of interest, the accessibility of the measurement volume is often limited or even impossible. To overcome these drawbacks, this paper introduces an in situ calibrated defocusing particle tracking velocimetry approach for wall-bounded measurement domains with depths in the low millimeter range. The calibration function for the particle depth location is directly derived from the particle image geometries and their displacements between two frames. Employing only a single camera, this defocusing approach is capable of measuring the air flow between two parallel glass plates at a distance of 1 mm with an average uncertainty of 2.43% for each track, relative to the maximum velocity. A tomographic particle tracking velocimetry measurement, serving as a benchmark for the single camera technique, reaches an average uncertainty of 1.59%. Altogether, with its straightforward set-up and without requiring a calibration target, this in situ calibrated defocusing approach opens new areas of application for optical flow velocimetry. In particular, for measurement domains with small optical windows and a lack of accessibility.

  9. A Nanoplasmonic Strategy for Precision in-situ Measurements of Tip-enhanced Raman and Fluorescence Spectroscopy

    PubMed Central

    Meng, Lingyan; Sun, Mengtao; Chen, Jianing; Yang, Zhilin

    2016-01-01

    We theoretically investigate an optimized tip-film system that supports in-situ measurement of tip-enhanced Raman spectroscopy (TERS) and tip-enhanced fluorescence (TEF) of dye molecules. A scanning tunneling microscope (STM) is proposed to precisely control the tip-film distance, and thus in-situ measurement of TERS and TEF can be realized utilizing the specific surface plasmon resonance (SPR) properties of the tip-film system. Our calculations show that the optimized tip-film distance of 2 nm suggests a possibility of efficient acquisition of TERS and TEF in-situ. The calculated spatial resolution of TERS and spectral resolution of TEF can be down to 6.5 nm and 10 nm, respectively. Our theoretical results may find promising application in developing multiple functional nano-spectroscopy through which Raman and fluorescence can be measured in-situ at the nanoscale level. PMID:26780882

  10. 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

  11. Climatology of 15 years of North Atlantic upper tropospheric relative humidity in-situ measurements by the MOZAIC programme

    NASA Astrophysics Data System (ADS)

    Neis, Patrick; Smit, Herman G. J.; Rohs, Susanne; Berkes, Florian; Boulanger, Damien; Nedelec, Philippe; Konopka, Paul; Hoor, Peter; Spichtinger, Peter; Petzold, Andreas

    2016-04-01

    Water vapour is a major parameter in weather prediction and climate research. However, the interaction between water vapour in the upper troposphere and lowermost stratosphere (UTLS) and tropopause dynamics are not well understood. Furthermore, the knowledge about potential trends and feedback mechanisms of upper troposphere/lower stratosphere water vapour is low because of the large variability of observations and relatively short data records. Since 1994, upper tropospheric humidity (UTH) data with high spatial and temporal resolution are provided by the in-situ measurements aboard civil passenger aircraft from the MOZAIC/IAGOS-programme (www.iagos.org). The measurement system is based on a capacitive hygrometer with a simultaneous temperature measurement. Comparison studies against research-grade water vapour instruments demonstrated successfully the qualification of the MOZAIC Capacitive Hygrometer (MCH) and its improved successor IAGOS Capacitive Hygrometer (ICH) for the use in long-term observation programmes. Moreover, the continuation of high data quality is confirmed for the transition from MCH to ICH (see P. Neis et al., 2015). After the reanalysis of the relative humidity data from 1994 to 2009 (see H. Smit et al., 2014), this extensive and unique data set is examined by criteria of continuity, homogeneity and quantity of data coverage, to identify global regions suitable for UTH climatology and trend analyses. For the identified target region above the North Atlantic time series and climatologies of, e.g., relative humidity with respect to ice, temperature, and absolute humidity are investigated. Different data sets selected according to geographic and atmospheric dynamics criteria and different tropopause definitions are compared for the robustness of the obtained results.

  12. 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.

  13. Theoretical and Experimental Errors for In Situ Measurements of Plant Water Potential 1

    PubMed Central

    Shackel, Kenneth A.

    1984-01-01

    Errors in psychrometrically determined values of leaf water potential caused by tissue resistance to water vapor exchange and by lack of thermal equilibrium were evaluated using commercial in situ psychrometers (Wescor Inc., Logan, UT) on leaves of Tradescantia virginiana (L.). Theoretical errors in the dewpoint method of operation for these sensors were demonstrated. After correction for these errors, in situ measurements of leaf water potential indicated substantial errors caused by tissue resistance to water vapor exchange (4 to 6% reduction in apparent water potential per second of cooling time used) resulting from humidity depletions in the psychrometer chamber during the Peltier condensation process. These errors were avoided by use of a modified procedure for dewpoint measurement. Large changes in apparent water potential were caused by leaf and psychrometer exposure to moderate levels of irradiance. These changes were correlated with relatively small shifts in psychrometer zero offsets (−0.6 to −1.0 megapascals per microvolt), indicating substantial errors caused by nonisothermal conditions between the leaf and the psychrometer. Explicit correction for these errors is not possible with the current psychrometer design. PMID:16663701

  14. Using continuous in-situ measurements to adaptively trigger urban storm water samples

    NASA Astrophysics Data System (ADS)

    Wong, B. P.; Kerkez, B.

    2015-12-01

    Until cost-effective in-situ sensors are available for biological parameters, nutrients and metals, automated samplers will continue to be the primary source of reliable water quality measurements. Given limited samples bottles, however, autosamplers often obscure insights on nutrient sources and biogeochemical processes which would otherwise be captured using a continuous sampling approach. To that end, we evaluate the efficacy a novel method to measure first-flush nutrient dynamics in flashy, urban watersheds. Our approach reduces the number of samples required to capture water quality dynamics by leveraging an internet-connected sensor node, which is equipped with a suite of continuous in-situ sensors and an automated sampler. To capture both the initial baseflow as well as storm concentrations, a cloud-hosted adaptive algorithm analyzes the high-resolution sensor data along with local weather forecasts to optimize a sampling schedule. The method was tested in a highly developed urban catchment in Ann Arbor, Michigan and collected samples of nitrate, phosphorus, and suspended solids throughout several storm events. Results indicate that the watershed does not exhibit first flush dynamics, a behavior that would have been obscured when using a non-adaptive sampling approach.

  15. In-situ Stress Measurement of MOVPE Growth of High Efficiency Lattice-Mismatched Solar Cells

    SciTech Connect

    Geisz, J. F.; Levander, A. X.; Norman, A. G.; Jones, K. M.; Romero, M. J.

    2007-04-01

    We have recently reported high efficiencies in a monolithic III-V triple-junction solar cell design that is grown inverted with a metamorphic 1.0 eV bottom In{sub .27}Ga{sub .73}As junction. The biaxial stress and strain grown into this highly lattice-mismatched junction can be controlled by varying the design of a step-graded Ga{sub x}In{sub 1-x}P buffer layer, in which most, but not all, of the 1.9% misfit strain is relieved. A multi-beam optical stress sensor (MOSS) is a convenient tool for in situ measurement of stress during metal-organic vapor phase epitaxy (MOVPE) for the optimization of solar cell performance. The analysis of stress from curvature data is complicated by significant temperature effects due to relatively small thermal gradients in our atmospheric-pressure MOVPE reactor. These temperature effects are discussed and approximations made to allow practical analysis of the data. The results show excellent performance of inverted In{sub .27}Ga{sub .73}. As solar cells grown with slight compressive stress, but degradation under tensile stress. The best devices had a V{sub oc} of 0.54 V and a dislocation density in the low 10{sup 6} cm{sup -2}. The in situ stress data is also compared with ex situ strain data derived from X-ray diffraction measurements.

  16. Spatial-frequency analysis algorithm for in-situ measurement of wavefront

    NASA Astrophysics Data System (ADS)

    Liu, Qian; Wang, Yang; Ji, Fang; He, Jianguo

    2015-05-01

    To apply phase-shifting interferometry (PSI) to in-situ measurement, we have proposed an algorithm to detect and suppress phase-shifting error and contrast fluctuation. The phase shift and contrast are analyzed in spatial-frequency domain. The strength of baseband and sideband implies the pattern contrast. The position and phase angle of the sideband indicates the tilt gradients and translational value of phase shift. Thus, the phase shift error and contrast fluctuation could be extracted. A contrast-compensated equation is established to calculate the wavefront phase. The proposed algorithm was applied to the interferograms subjecting to vibration and wavefront phase was calculated. The experimental results show that, under vibration of one micron amplitude and 60Hz frequency, the error of wavefront PV value is less than 0.01wave and the 2σ repeatability is less than 0.01wave. For no hardware is required, the proposed algorithm provides a cost-effective method for wavefront in-situ measurement with PSI.

  17. Analysis of a vortex precipitation event over Southwest China using AIRS and in situ measurements

    NASA Astrophysics Data System (ADS)

    Ni, Chengcheng; Li, Guoping; Xiong, Xiaozhen

    2017-04-01

    A strong precipitation event caused by the southwest vortex (SWV), which affected Sichuan Province and Chongqing municipality in Southwest China on 10-14 July 2012, is investigated. The SWV is examined using satellite observations from AIRS (Atmospheric Infrared Sounder), in situ measurements from the SWV intensive observation campaign, and MICAPS (Marine Interactive Computer-Aided Provisioning System) data. Analysis of this precipitation process revealed that: (1) heavy rain occurred during the development phase, and cloud water content increased significantly after the dissipation of the SWV; (2) the area with low outgoing longwave radiation values from AIRS correlated well with the SWV; (3) variation of the temperature of brightness blackbody (TBB) from AIRS reflected the evolution of the SWV, and the values of TBB reduced significantly during the SWV's development; and (4) strong temperature and water vapor inversions were noted during the development of the SWV. The moisture profile displayed large vertical variation during the SWV's puissant phase, with the moisture inversion occurring at low levels. The moisture content during the receding phase was significantly reduced compared with that during the developing and puissant phases. The vertical flux of vapor divergence explained the variation of the moisture profile. These results also indicate the potential for using AIRS products in studying severe weather over the Tibetan Plateau and its surroundings, where in situ measurements are sparse.

  18. Reconciling Spectroscopic Electron Temperature Measurements in the Solar Corona with In Situ Charge State Observations.

    PubMed

    Esser; Edgar

    2000-03-20

    It has been a puzzle for quite some time that spectroscopic measurements in the inner corona indicate electron temperatures far too low to produce the ion fractions observed in situ in the solar wind. In the present Letter, we show that in order to reconcile the two sets of measurements, a number of conditions have to exist in the inner corona: (1) The electron distribution function has to be Maxwellian or close to Maxwellian at the coronal base, (2) the non-Maxwellian character of the distribution has to develop rapidly as a function of height and has to reach close to interplanetary properties inside of a few solar radii, and (3) ions of different elements have to flow with significantly different speeds to separate their "freezing-in" distances sufficiently so that they can encounter different distribution functions. We choose two examples to demonstrate that these conditions are general requirements if both coronal electron temperatures and in situ ion fractions are correct. However, these two examples also show that the details of the required distribution functions are very sensitive to the exact electron temperature, density, and ion flow speed profiles in the region of the corona where the ions predominantly form.

  19. Deriving an atmospheric budget of total organic bromine using airborne in situ measurements from the western Pacific area during SHIVA

    NASA Astrophysics Data System (ADS)

    Sala, S.; Bönisch, H.; Keber, T.; Oram, D. E.; Mills, G.; Engel, A.

    2014-07-01

    During the recent SHIVA (Stratospheric Ozone: Halogen Impacts in a Varying Atmosphere) project an extensive data set of all halogen species relevant for the atmospheric budget of total organic bromine was collected in the western Pacific region using the Falcon aircraft operated by the German Aerospace agency DLR (Deutsches Zentrum für Luft- und Raumfahrt) covering a vertical range from the planetary boundary layer up to the ceiling altitude of the aircraft of 13 km. In total, more than 700 measurements were performed with the newly developed fully automated in situ instrument GHOST-MS (Gas chromatograph for the Observation of Tracers - coupled with a Mass Spectrometer) by the Goethe University of Frankfurt (GUF) and with the onboard whole-air sampler WASP with subsequent ground-based state-of-the-art GC / MS analysis by the University of East Anglia (UEA). Both instruments yield good agreement for all major (CHBr3 and CH2Br2) and minor (CH2BrCl, CHBrCl2 and CHBr2Cl) VSLS (very short-lived substances), at least at the level of their 2σ measurement uncertainties. In contrast to the suggestion that the western Pacific could be a region of strongly increased atmospheric VSLS abundance (Pyle et al., 2011), we found only in the upper troposphere a slightly enhanced amount of total organic bromine from VSLS relative to the levels reported in Montzka and Reimann et al. (2011) for other tropical regions. From the SHIVA observations in the upper troposphere, a budget for total organic bromine, including four halons (H-1301, H-1211, H-1202, H-2402), CH3Br and the VSLS, is derived for the level of zero radiative heating (LZRH), the input region for the tropical tropopause layer (TTL) and thus also for the stratosphere. With the exception of the two minor VSLS CHBrCl2 and CHBr2Cl, excellent agreement with the values reported in Montzka and Reimann et al. (2011) is found, while being slightly higher than previous studies from our group based on balloon-borne measurements.

  20. An airborne infrared laser spectrometer for in-situ trace gas measurements: application to tropical convection case studies

    NASA Astrophysics Data System (ADS)

    Catoire, V.; Krysztofiak, G.; Robert, C.; Chartier, M.; Jacquet, P.; Guimbaud, C.; Hamer, P. D.; Marécal, V.

    2015-09-01

    A three-channel laser absorption spectrometer called SPIRIT (SPectromètre InfraRouge In situ Toute altitude) has been developed for airborne measurements of trace gases in the troposphere and lower stratosphere. More than three different species can be measured simultaneously with high time resolution (each 1.6 s) using three individual CW-DFB-QCLs (Continuous Wave Distributed FeedBack Quantum Cascade Lasers) coupled to a single Robert multipass optical cell. The lasers are operated in a time-multiplexed mode. Absorption of the mid-infrared radiations occur in the cell (2.8 L with effective path lengths of 134 to 151 m) at reduced pressure, with detection achieved using a HgCdTe detector cooled by Stirling cycle. The performances of the instrument are described, in particular precisions of 1, 1 and 3 %, and volume mixing ratio (vmr) sensitivities of 0.4, 6 and 2.4 ppbv are determined at 1.6 s for CO, CH4 and N2O, respectively (at 1σ confidence level). Estimated accuracies without calibration are about 6 %. Dynamic measuring ranges of about four decades are established. The first deployment of SPIRIT was realized aboard the Falcon-20 research aircraft operated by DLR (Deutsches Zentrum für Luft- und Raumfahrt) within the frame of the SHIVA (Stratospheric Ozone: Halogen Impacts in a Varying Atmosphere) European project in November-December 2011 over Malaysia. The convective outflows from two large convective systems near Borneo Island (6.0° N-115.5° E and 5.5° N-118.5° E) were sampled above 11 km in altitude on 19 November and 9 December, respectively. Correlated enhancements in CO and CH4 vmr were detected when the aircraft crossed the outflow anvil of both systems. These enhancements were interpreted as the fingerprint of transport from the boundary layer up through the convective system and then horizontal advection in the outflow. Using these observations, the fraction of boundary layer air contained in fresh convective outflow was calculated to range

  1. Probing the impact of different aerosol sources on cloud microphysics and precipitation through in-situ measurements of chemical mixing state

    NASA Astrophysics Data System (ADS)

    Prather, K. A.; Suski, K.; Cazorla, A.; Cahill, J. F.; Creamean, J.; Collins, D. B.; Heymsfield, A.; Roberts, G. C.; DeMott, P. J.; Sullivan, R. C.; Rosenfeld, D.; Comstock, J. M.; Tomlinson, J. M.

    2011-12-01

    Aerosol particles play a crucial role in affecting cloud processes by serving as cloud nuclei. However, our understanding of which particles actually form cloud and ice nuclei limits our ability to treat aerosols properly in climate models. In recent years, it has become possible to measure the chemical composition of individual cloud nuclei within the clouds using on-line mass spectrometry. In-situ high time resolution chemistry can now be compared with cloud physics measurements to directly probe the impact of aerosol chemistry on cloud microphysics. This presentation will describe results from two recent field campaigns, CalWater in northern California and ICE-T in the western Caribbean region. Ground-based and aircraft measurements will be presented of aerosol mixing state, cloud microphysics, and meteorology. Results from single particle mass spectrometry will show the sources of the cloud seeds, including dust, biomass burning, sea spray, and biological particles. Details will be provided on how we are now able to probe the sources and cycling of atmospheric aerosols by measuring individual aerosols, cloud nuclei, and precipitation chemistry. The important role of dust, both Asian and African, and bioparticles in forming ice nuclei will be discussed. Finally, a summary will be provided discussing how these new in-situ measurements are being used to advance our understanding of complex atmospheric processes, and improve our understanding of aerosol impacts on climate.

  2. 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.

  3. Inferring immobile and in-situ water saturation from laboratory and field measurements

    SciTech Connect

    Belen, Rodolfo P., Jr.

    2000-06-01

    Analysis of experimental data and numerical simulation results of dynamic boiling experiments revealed that there is an apparent correlation between the immobile water saturation and the shape of the steam saturation profile. An elbow in the steam saturation profile indicates the sudden drop in steam saturation that marks the transition from steam to two-phase conditions inside the core during boiling. The immobile water saturation can be inferred from this elbow in the steam saturation profile. Based on experimental results obtained by Satik (1997), the inferred immobile water saturation of Berea sandstone was found to be about 0.25, which is consistent with results of relative permeability experiments reported by Mahiya (1999). However, this technique may not be useful in inferring the immobile water saturation of less permeable geothermal rocks because the elbow in the steam saturation profile is less prominent. Models of vapor and liquid-dominated geothermal reservoirs that were developed based on Darcy's law and material and energy conservation equations proved to be useful in inferring the in-situ and immobile water saturations from field measurements of cumulative mass production, discharge enthalpy, and downhole temperature. Knowing rock and fluid properties, and the difference between the stable initial, T{sub o}, and dry-out, T{sub d}, downhole temperatures, the in-situ and immobile water saturations of vapor-dominated reservoirs can be estimated. On the other hand, the in-situ and immobile water saturations, and the change in mobile water content of liquid-dominated reservoirs can be inferred from the cumulative mass production, {Delta}m, and enthalpy, h{prime}, data. Comparison with two-phase, radial flow, numerical simulation results confirmed the validity and usefulness of these models.

  4. MAX200x: In-situ X-ray Measurements at High Pressure and High Temperatures.

    NASA Astrophysics Data System (ADS)

    Lathe, C.; Mueller, H. J.; Wehber, M.; Lauterjung, J.; Schilling, F. R.

    2009-05-01

    Twenty years ago geoscientists from all over the world launched in-situ X-ray diffraction experiments under extreme pressure and temperature conditions at synchrotron beamlines. One of the first apparatus was installed at HASYLAB, MAX80, a single-stage multi-anvil system. MAX80 allows in-situ diffraction studies in conjunction with the simultaneous measurement of elastic properties up to 12 GPa and 1600 K. This very successful experiment, unique in Europe, is operated by Helmholtz Centre Potsdam and is used by more than twenty groups from different countries every year. Experiments for both, applied and basic research are conducted, ranging from life-sciences, chemistry, physics, over material sciences to geosciences. Today new materials and the use of high brilliant synchrotron sources allow constructing double-stage multi-anvil systems for X-ray diffraction to reach much higher pressures. The newly designed high-flux hard wiggler (HARWI-II) beamline is an ideal X-ray source for this kind of experiments. As only the uppermost few kilometres of the Earth (less than 0.1% of its radius) are accessible for direct observations (e.g. deep drilling), sophisticated techniques are required to observe and to understand the processes in the deep interior of our planet. In-situ studies are an excellent tool to investigate ongoing geodynamic processes within the laboratory. One of the fundamental regions to study geodynamic processes seems to be the so-called transition zone, the boundary between upper and lower Earth's mantle between 410 and 670 km depth. Mineral reactions, phase transitions, as wheel as fluid rock interaction in this area might have the potential to strongly influence and control the dynamic motions within our whole planet. Around 25 GPa and 2 000 K are required to simulate these processes in the laboratory. The new MAX200x will be an excellent tool for these ambitious experiments.

  5. In situ measurements of KZ and ɛ compared to numerical models in the Gulf of Lion.

    NASA Astrophysics Data System (ADS)

    Costa, Andrea; Doglioli, Andrea; Dekeyser, Ivan; Jullion, Loic; Malengros, Deny; Petrenko, Anne

    2015-04-01

    Vertical diffusivity and turbulent kinetic energy dissipation rate play an essential role in the parametrization of physical and biogeochemical models. Coastal environment is particularly important because expected to contribute in a substantial way to the balance of kinetic energy in the ocean. In situ measurements have a crucial importance in driving the models. We present a multi-annual dataset performed with SCAMP (Self Contained Autonomous Profiler) field measurements of KZ and ɛ in a variety of meteorological and oceanic conditions in the Gulf of Lion (Mediterranean Sea). The results are compared with respect to similar measurements in coastal waters described in literature. Moreover, a comparison to numerical circulation models is proposed in order to show the dependency of the depth of the mixing layer on the wind forcing.

  6. In Situ Stress Measurements in the NPR Hole, Volume I - Results and Interpretations

    SciTech Connect

    Moos, D.

    2001-10-15

    This report presents the results of an investigation of the magnitudes and orientations of the in situ stresses in basement rocks beneath the Savannah River Site (SRS). Stress magnitudes were measured using the hydraulic fracturing technique. Stress orientations were obtained from the orientation of stress-induced wellbore breakouts and hydraulically-induced fractures. The measurements reported here were carried out in the New Production Reactor (NPR) hole, drilled to a total depth of 4000 feet near the center of the Savannah River Site, at roughly the location of the proposed NPR. The results obtained in this study are compared to previous stress measurements made using the same techniques in a series of shallower holes on the SRS, and discussed in the context of the regional stress field and potential seismic hazard.

  7. Note: In situ measurement of vacuum window birefringence by atomic spectroscopy.

    PubMed

    Steffen, Andreas; Alt, Wolfgang; Genske, Maximilian; Meschede, Dieter; Robens, Carsten; Alberti, Andrea

    2013-12-01

    We present an in situ method to measure the birefringence of a single vacuum window by means of microwave spectroscopy on an ensemble of cold atoms. Stress-induced birefringence can cause an ellipticity in the polarization of an initially linearly polarized laser beam. The amount of ellipticity can be reconstructed by measuring the differential vector light shift of an atomic hyperfine transition. Measuring the ellipticity as a function of the linear polarization angle allows us to infer the amount of birefringence Δn at the level of 10(-8) and identify the orientation of the optical axes. The key benefit of this method is the ability to separately characterize each vacuum window, allowing the birefringence to be precisely compensated in existing vacuum apparatuses.

  8. Note: In situ measurement of vacuum window birefringence by atomic spectroscopy

    SciTech Connect

    Steffen, Andreas; Alt, Wolfgang; Genske, Maximilian; Meschede, Dieter; Robens, Carsten; Alberti, Andrea

    2013-12-15

    We present an in situ method to measure the birefringence of a single vacuum window by means of microwave spectroscopy on an ensemble of cold atoms. Stress-induced birefringence can cause an ellipticity in the polarization of an initially linearly polarized laser beam. The amount of ellipticity can be reconstructed by measuring the differential vector light shift of an atomic hyperfine transition. Measuring the ellipticity as a function of the linear polarization angle allows us to infer the amount of birefringence Δn at the level of 10{sup −8} and identify the orientation of the optical axes. The key benefit of this method is the ability to separately characterize each vacuum window, allowing the birefringence to be precisely compensated in existing vacuum apparatuses.

  9. Development of a Cone Penetrometer for Measuring Spectral Characteristics of Soils in Situ

    NASA Technical Reports Server (NTRS)

    Lee, Landris T., Jr.; Malone, Philip G.

    1993-01-01

    A patent was recently granted to the U.S. Army for an adaptation of a soil cone penetrometer that can be used to measure the spectral characteristics (fluorescence or reflectance) of soils adjacent to the penetrometer rod. The system can use a variety of light sources and spectral analytical equipment. A laser induced fluorescence measuring system has proven to be of immediate use in mapping the distribution of oil contaminated soil at waste disposal and oil storage areas. The fiber optic adaptation coupled with a cone penetrometer permits optical characteristics of the in-situ soil to be measured rapidly, safely, and inexpensively. The fiber optic cone penetrometer can be used to gather spectral data to a depth of approximately 25 to 30 m even in dense sands or stiff clays and can investigate 300 m of soil per day. Typical detection limits for oil contamination in sand is on the order of several hundred parts per million.

  10. Sub-Kelvin magnetic and electrical measurements in a diamond anvil cell with in situ tunability

    NASA Astrophysics Data System (ADS)

    Palmer, A.; Silevitch, D. M.; Feng, Yejun; Wang, Yishu; Jaramillo, R.; Banerjee, A.; Ren, Y.; Rosenbaum, T. F.

    2015-09-01

    We discuss techniques for performing continuous measurements across a wide range of pressure-field-temperature phase space, combining the milli-Kelvin temperatures of a helium dilution refrigerator with the giga-Pascal pressures of a diamond anvil cell and the Tesla magnetic fields of a superconducting magnet. With a view towards minimizing remnant magnetic fields and background magnetic susceptibility, we characterize high-strength superalloy materials for the pressure cell assembly, which allows high fidelity measurements of low-field phenomena such as superconductivity below 100 mK at pressures above 10 GPa. In situ tunability and measurement of the pressure permit experiments over a wide range of pressure, while at the same time making possible precise steps across abrupt phase transitions such as those from insulator to metal.

  11. Development of an in situ thermal conductivity measurement system for exploration of the shallow subsurface

    NASA Astrophysics Data System (ADS)

    Chirila, Marian Andrei; Christoph, Benjamin; Vienken, Thomas; Dietrich, Peter; Bumberger, Jan

    2016-06-01

    In this study, we attempted to develop an in situ thermal conductivity measurement system that can be used for subsurface thermal exploration. A new thermal probe was developed for mapping both the spatial and temporal variability of thermal conductivity, via direct push methods in the unconsolidated shallow subsurface. A robust, hollow cylindrical probe was constructed and its performance was tested by carrying out thermal conductivity measurements on materials with known properties. The thermal conductivity of the investigated materials can be worked out by measuring the active power consumption (in alternating current system) and temperature of the probe over fixed time intervals. A calibration method was used to eliminate any undesired thermal effects regarding the size of the probe, based on mobile thermal analyzer thermal conductivity values. Using the hollow cylindrical probe, the thermal conductivity results obtained had an error of less than 2.5% for solid samples (such as Teflon, Agar Jelly and Nylatron).

  12. Sub-Kelvin magnetic and electrical measurements in a diamond anvil cell with in situ tunability.

    PubMed

    Palmer, A; Silevitch, D M; Feng, Yejun; Wang, Yishu; Jaramillo, R; Banerjee, A; Ren, Y; Rosenbaum, T F

    2015-09-01

    We discuss techniques for performing continuous measurements across a wide range of pressure-field-temperature phase space, combining the milli-Kelvin temperatures of a helium dilution refrigerator with the giga-Pascal pressures of a diamond anvil cell and the Tesla magnetic fields of a superconducting magnet. With a view towards minimizing remnant magnetic fields and background magnetic susceptibility, we characterize high-strength superalloy materials for the pressure cell assembly, which allows high fidelity measurements of low-field phenomena such as superconductivity below 100 mK at pressures above 10 GPa. In situ tunability and measurement of the pressure permit experiments over a wide range of pressure, while at the same time making possible precise steps across abrupt phase transitions such as those from insulator to metal.

  13. In situ measurements of contributions to the global electrical circuit by a thunderstorm in southeastern Brazil

    USGS Publications Warehouse

    Thomas, J.N.; Holzworth, R.H.; McCarthy, M.P.

    2009-01-01

    The global electrical circuit, which maintains a potential of about 280??kV between the earth and the ionosphere, is thought to be driven mainly by thunderstorms and lightning. However, very few in situ measurements of electrical current above thunderstorms have been successfully obtained. In this paper, we present dc to very low frequency electric fields and atmospheric conductivity measured in the stratosphere (30-35??km altitude) above an active thunderstorm in southeastern Brazil. From these measurements, we estimate the mean quasi-static conduction current during the storm period to be 2.5 ?? 1.25??A. Additionally, we examine the transient conduction currents following a large positive cloud-to-ground (+ CG) lightning flash and typical - CG flashes. We find that the majority of the total current is attributed to the quasi-static thundercloud charge, rather than lightning, which supports the classical Wilson model for the global electrical circuit.

  14. Sub-Kelvin magnetic and electrical measurements in a diamond anvil cell with in situ tunability

    SciTech Connect

    Palmer, A; Silevitch, D M; Feng, Yejun; Wang, Y; Jaramillo, R.; Banerjee, A.; Ren, Y.; Rosenbaum, T. F.

    2015-09-01

    We discuss techniques for performing continuous measurements across a wide range of pressure–field–temperature phase space, combining the milli-Kelvin temperatures of a helium dilution refrigerator with the giga-Pascal pressures of a diamond anvil cell and the Tesla magnetic fields of a superconducting magnet. With a view towards minimizing remnant magnetic fields and background magnetic susceptibility, we characterize high-strength superalloy materials for the pressure cell assembly, which allows high fidelity measurements of low-field phenomena such as superconductivity below 100 mK at pressures above 10 GPa. In situ tunability and measurement of the pressure permit experiments over a wide range of pressure, while at the same time making possible precise steps across abrupt phase transitions such as those from insulator to metal.

  15. Recent achievements for In-situ measurement: applications to an actual decommissioning project

    SciTech Connect

    Lamadie, F.; Girones, P.; Le Goaller, C.; Mahe, C.; Kohler, J.Y.; Risser, M.A.

    2007-07-01

    Decommissioning a nuclear facility implies a policy of limiting the waste volume and its chemical - and especially radiological - toxicity. It is therefore important to determine the activity level contained in each component that will be dismantled. A variety of methods and analysis techniques are used for this purpose, ranging from simple dose rate measurements to {gamma} spectrometry and {gamma} imaging. The results of several measurement campaigns in a reactor currently in operation but for which decommissioning studies have now been undertaken are discussed. The measurements provide additional radiological data for the waste inventory, which is one of the first issues to be examined. This discussion focuses on the methods used ({gamma} imaging, in situ {gamma} spectrometry, etc.), the results obtained, and their implications for the project, as well as the technological and methodological innovations implemented during these campaigns. (authors)

  16. In situ measurement of the reinforcement modulus in a metal matrix composite by acoustic microscopy

    SciTech Connect

    Canumalla, S.; Gordon, G.A.; Pangborn, R.N.

    1995-12-31

    The mechanical properties of metal-matrix composites have been observed to be a strong function of the content of non-fiber inclusions. Shot particles, with the nominal composition of the reinforcement, have been found to crack prematurely, thus representing prefer-red failure initiation sites under mechanical and thermal fatigue of discontinuous, alumina-silicate fiber reinforced aluminum matrix composites. To better understand the differences between the responses of the shot and fibers to loading, the Young`s modulus of the shot is measured and compared to that of the fibers. Scanning acoustic microscopy is used to nondestructively measure the modulus of the shot in situ, and the fiber modulus is obtained from the previously measured composite response. The shot, with a modulus of 131.5 GPa, has a Young`s modulus that is approximately 40% lower than that of the fibers. The influence of this on the composite response will be discussed.

  17. Airborne aerosol in situ measurements during TCAP: A closure study of total scattering

    SciTech Connect

    Kassianov, Evgueni; Sedlacek, Arthur; Berg, Larry K.; Pekour, Mikhail; Barnard, James; Chand, Duli; Flynn, Connor; Ovchinnikov, Mikhail; Schmid, Beat; Shilling, John; Tomlinson, Jason; Fast, Jerome

    2015-07-31

    We present a framework for calculating the total scattering of both non-absorbing and absorbing aerosol at ambient conditions from aircraft data. Our framework is developed emphasizing the explicit use of chemical composition data for estimating the complex refractive index (RI) of particles, and thus obtaining improved ambient size spectra derived from Optical Particle Counter (OPC) measurements. The feasibility of our framework for improved calculations of total scattering is demonstrated using three types of data collected by the U.S. Department of Energy’s (DOE) aircraft during the Two-Column Aerosol Project (TCAP). Namely, these data types are: (1) size distributions measured by a suite of OPC’s; (2) chemical composition data measured by an Aerosol Mass Spectrometer and a Single Particle Soot Photometer; and (3) the dry total scattering coefficient measured by a integrating nephelometer and scattering enhancement factor measured with a humidification system. We demonstrate that good agreement (~10%) between the observed and calculated scattering can be obtained under ambient conditions (RH < 80%) by applying chemical composition data for the RI-based correction of the OPC-derived size spectra. We also demonstrate that ignoring the RI-based correction or using non-representative RI values can cause a substantial underestimation (~40%) or overestimation (~35%) of the calculated scattering, respectively.

  18. Airborne aerosol in situ measurements during TCAP: A closure study of total scattering

    DOE PAGES

    Kassianov, Evgueni; Sedlacek, Arthur; Berg, Larry K.; ...

    2015-07-31

    We present a framework for calculating the total scattering of both non-absorbing and absorbing aerosol at ambient conditions from aircraft data. Our framework is developed emphasizing the explicit use of chemical composition data for estimating the complex refractive index (RI) of particles, and thus obtaining improved ambient size spectra derived from Optical Particle Counter (OPC) measurements. The feasibility of our framework for improved calculations of total scattering is demonstrated using three types of data collected by the U.S. Department of Energy’s (DOE) aircraft during the Two-Column Aerosol Project (TCAP). Namely, these data types are: (1) size distributions measured by amore » suite of OPC’s; (2) chemical composition data measured by an Aerosol Mass Spectrometer and a Single Particle Soot Photometer; and (3) the dry total scattering coefficient measured by a integrating nephelometer and scattering enhancement factor measured with a humidification system. We demonstrate that good agreement (~10%) between the observed and calculated scattering can be obtained under ambient conditions (RH < 80%) by applying chemical composition data for the RI-based correction of the OPC-derived size spectra. We also demonstrate that ignoring the RI-based correction or using non-representative RI values can cause a substantial underestimation (~40%) or overestimation (~35%) of the calculated scattering, respectively.« less

  19. 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.

  20. Satellite (Timed, Aura, Aqua) and In Situ (Meteorological Rockets, Balloons) Measurement Comparability

    NASA Technical Reports Server (NTRS)

    Schmidlin, F. J.; Goldberg, Richard A.; Feofilov, A.; Rose, R.

    2010-01-01

    Measurements using the inflatable falling sphere often are requested to provide density data in support of special sounding rocket launchings into the mesosphere and thermosphere. To insure density measurements within narrow time frames and close in space, the inflatable falling sphere is launched within minutes of the major test. Sphere measurements are reliable for the most part, however, availability of these rocket systems has become more difficult and, in fact, these instruments no longer are manufactured resulting in a reduction of the meager stockpile of instruments. Sphere measurements also are used to validate remotely measured temperatures and have the advantage of measuring small-scale atmospheric features. Even so, with the dearth of remaining falling spheres perhaps it is time to consider whether the remote measurements are mature enough to stand alone. Presented are two field studies, one in 2003 from Northern Sweden and one in 2010 from the vicinity of Kwajalein Atoll that compare temperature retrievals between satellite and in situ failing spheres. The major satellite instruments employed are SABER, MLS, and AIRS. The comparisons indicate that remotely measured temperatures mimic the sphere temperature measurements quite well. The data also confirm that satellite retrievals, while not always at the exact location required for individual studies, are adaptable enough and highly useful. Although the falling sphere will provide a measurement at a specific location and time, satellites only pass a given location daily or less often. This report reveals that averaged satellite measurements can provide temperatures and densities comparable to the falling sphere.

  1. In-situ soil composition and moisture measurement by surface neutron activation analysis

    NASA Astrophysics Data System (ADS)

    Waring, C.; Smith, C.; Marks, A.

    2009-04-01

    Neutron activation analysis is widely known as a laboratory technique dependent upon a nuclear reactor to provide the neutron flux and capable of precise elemental analysis. Less well known in-situ geochemical analysis is possible with isotopic (252Cf & 241Am) or compact accelerator (D-T, D-D fusion reaction) neutron sources. Prompt gamma neutron activation analysis (PGNAA) geophysical borehole logging has been applied to mining issues for >15 years (CSIRO) using isotopic neutron sources and more recently to environmental and hydro-geological applications by ANSTO. Similarly, sophisticated geophysical borehole logging equipment based on inelastic neutron scattering (INS) has been applied in the oil and gas industry by large oilfield services companies to measure oil saturation indices (carbon/oxygen) using accelerator neutron sources. Recent advances in scintillation detector spectral performance has enabled improved precision and detection limits for elements likely to be present in soil profiles (H, Si, Al, Fe, Cl) and possible detection of many minor to trace elements if sufficiently abundant (Na, K, Mg, Ca, S, N, + ). To measure carbon an accelerator neutron source is required to provide fast neutrons above 4.8 MeV. CSIRO and ANSTO propose building a soil geochemical analysis system based on experience gained from building and applying PGNA borehole logging equipment. A soil geochemical analysis system could effectively map the 2D geochemical composition of the top 50cm of soil by dragging the 1D logging equipment across the ground surface. Substituting an isotopic neutron source for a D-T accelerator neutron source would enable the additional measurement of elemental carbon. Many potential ambiguities with other geophysical proxies for soil moisture may be resolved by direct geochemical measurement of H. Many other applications may be possible including time series in-situ measurements of soil moisture for differential drainage, hydrology, land surface

  2. A review of uncertainty in in situ measurements and data sets of sea surface temperature

    NASA Astrophysics Data System (ADS)

    Kennedy, John J.

    2014-03-01

    Archives of in situ sea surface temperature (SST) measurements extend back more than 160 years. Quality of the measurements is variable, and the area of the oceans they sample is limited, especially early in the record and during the two world wars. Measurements of SST and the gridded data sets that are based on them are used in many applications so understanding and estimating the uncertainties are vital. The aim of this review is to give an overview of the various components that contribute to the overall uncertainty of SST measurements made in situ and of the data sets that are derived from them. In doing so, it also aims to identify current gaps in understanding. Uncertainties arise at the level of individual measurements with both systematic and random effects and, although these have been extensively studied, refinement of the error models continues. Recent improvements have been made in the understanding of the pervasive systematic errors that affect the assessment of long-term trends and variability. However, the adjustments applied to minimize these systematic errors are uncertain and these uncertainties are higher before the 1970s and particularly large in the period surrounding the Second World War owing to a lack of reliable metadata. The uncertainties associated with the choice of statistical methods used to create globally complete SST data sets have been explored using different analysis techniques, but they do not incorporate the latest understanding of measurement errors, and they want for a fair benchmark against which their skill can be objectively assessed. These problems can be addressed by the creation of new end-to-end SST analyses and by the recovery and digitization of data and metadata from ship log books and other contemporary literature.

  3. Galileo in-situ dust measurements and the sculpting of Jupiter's gossamer rings by its shadow

    NASA Astrophysics Data System (ADS)

    Krüger, Harald; Hamilton, Douglas P.; Moissl, Richard; Grün, Eberhard

    2008-09-01

    Galileo was the first articfiial satellite to orbit Jupiter. During its late orbital mission the spacecraft made two passages through the giant planet's gossamer ring system. The highly sensitive impact-ionization dust detector on board successfully recorded dust impacts during both ring passages and provided the first in-situ measurements from a dusty planetary ring. During the first passage { on 5 November 2002 while Galileo was approaching Jupiter - dust measurements were collected until a spacecraft anomaly at 2:33RJ (Jupiter radii) just 16 min after a close flyby of Amalthea put the spacecraft into a safing mode. The second ring passage on 21 September 2003 provided ring dust measurements down to about 2:5RJ and the Galileo spacecraft was destroyed shortly thereafter in a planned impact with Jupiter. In all, a few thousand dust impacts were counted with the instrument accumulators during both ring passages, but only a total of 110 complete data sets of dust impacts were transmitted to Earth (Krüger et al, Icarus, submitted). Detected particle sizes range from about 0.2 to 5 μm, extending the known size distribution by an order of magnitude towards smaller particles than previously derived from optical imaging (Showalter et al., Icarus 2008). The grain size distribution increases towards smaller particles and shows an excess of these tiny motes in the Amalthea gossamer ring compared to the Thebe ring. The size distribution for the Amalthea ring derived from our in-situ measurements for the small grains agrees very well with the one obtained from images for large grains. Our analysis shows that particles contributing most to the optical cross-section are approximately 5 μm in radius, in agreement with imaging results. The measurements indicate a large drop in particle ux immediately interior to Thebe's orbit and some detected particles seem to be on highly-tilted orbits with inclinations up to 20°. Finally, the faint Thebe ring extension was detected out to

  4. In-Situ Measurement of Hall Thruster Erosion Using a Fiber Optic Regression Probe

    NASA Technical Reports Server (NTRS)

    Polzin, Kurt; Korman, Valentin

    2009-01-01

    One potential life-limiting mechanism in a Hall thruster is the erosion of the ceramic material comprising the discharge channel. This is especially true for missions that require long thrusting periods and can be problematic for lifetime qualification, especially when attempting to qualify a thruster by analysis rather than a test lasting the full duration of the mission. In addition to lifetime, several analytical and numerical models include electrode erosion as a mechanism contributing to enhanced transport properties. However, there is still a great deal of dispute over the importance of erosion to transport in Hall thrusters. The capability to perform an in-situ measurement of discharge channel erosion is useful in addressing both the lifetime and transport concerns. An in-situ measurement would allow for real-time data regarding the erosion rates at different operating points, providing a quick method for empirically anchoring any analysis geared towards lifetime qualification. Erosion rate data over a thruster s operating envelope would also be useful in the modeling of the detailed physics inside the discharge chamber. There are many different sensors and techniques that have been employed to quantify discharge channel erosion in Hall thrusters. Snapshots of the wear pattern can be obtained at regular shutdown intervals using laser profilometry. Many non-intrusive techniques of varying complexity and sensitivity have been employed to detect the time-varying presence of erosion products in the thruster plume. These include the use quartz crystal microbalances, emission spectroscopy, laser induced flourescence, and cavity ring-down spectroscopy. While these techniques can provide a very accurate picture of the level of eroded material in the thruster plume, it is more difficult to use them to determine the location from which the material was eroded. Furthermore, none of the methods cited provide a true in-situ measure of erosion at the channel surface while

  5. 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.

  6. 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

  7. 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.

  8. Passive remote sensing of large-scale methane emissions from Oil Fields in California's San Joaquin Valley and validation by airborne in-situ measurements - Results from COMEX

    NASA Astrophysics Data System (ADS)

    Gerilowski, Konstantin; Krautwurst, Sven; Thompson, David R.; Thorpe, Andrew K.; Kolyer, Richard W.; Jonsson, Haflidi; Krings, Thomas; Frankenberg, Christian; Horstjann, Markus; Leifer, Ira; Eastwood, Michael; Green, Robert O.; Vigil, Sam; Fladeland, Matthew; Schüttemeyer, Dirk; Burrows, John P.; Bovensmann, Heinrich

    2016-04-01

    The CO2 and MEthane EXperiment (COMEX) was a NASA and ESA funded campaign in support of the HyspIRI and CarbonSat mission definition activities. As a part of this effort, seven flights were performed between June 3 and September 4, 2014 with the Methane Airborne MAPper (MAMAP) remote sensing instrument (operated by the University of Bremen in cooperation with the German Research Centre for Geosciences - GFZ) over the Kern River, Kern Front, and Poso Creek Oil Fields located in California's San Joaquin Valley. MAMAP was installed for the flights aboard the Center for Interdisciplinary Remotely-Piloted Aircraft Studies (CIRPAS) Twin Otter aircraft, together with: a Picarro fast in-situ greenhouse gas (GHG) analyzer operated by the NASA Ames Research Center, ARC; a 5-hole turbulence probe; and an atmospheric measurement package operated by CIRPAS measuring aerosols, temperature, dew-point, and other atmospheric parameters. Three of the flights were accompanied by the Next Generation Airborne Visual InfraRed Imaging Spectrometer (AVIRIS-NG), operated by the Jet Propulsion Laboratory (JPL), California Institute of Technology, installed aboard a second Twin Otter aircraft. Large-scale, high-concentration CH4 plumes were detected by the MAMAP instrument over the fields and tracked over several kilometers. The spatial distribution of the MAMAP observed plumes was compared to high spatial resolution CH4 anomaly maps derived by AVIRIS-NG imaging spectroscopy data. Remote sensing data collected by MAMAP was used to infer CH4 emission rates and their distributions over the three fields. Aggregated emission estimates for the three fields were compared to aggregated emissions inferred by subsequent airborne in-situ validation measurements collected by the Picarro instrument. Comparison of remote sensing and in-situ flux estimates will be presented, demonstrating the ability of airborne remote sensing data to provide accurate emission estimates for concentrations above the

  9. Turbulence in breaking mountain waves and atmospheric rotors estimated from airborne in situ and Doppler radar measurements.

    PubMed

    Strauss, Lukas; Serafin, Stefano; Haimov, Samuel; Grubišić, Vanda

    2015-10-01

    Atmospheric turbulence generated in flow over mountainous terrain is studied using airborne in situ and cloud radar measurements over the Medicine Bow Mountains in southeast Wyoming, USA. During the NASA Orographic Clouds Experiment (NASA06) in 2006, two complex mountain flow cases were documented by the University of Wyoming King Air research aircraft carrying the Wyoming Cloud Radar. The structure of turbulence and its intensity across the mountain range are described using the variance of vertical velocity σw2 and the cube root of the energy dissipation rate ɛ(1/3) (EDR). For a quantitative analysis of turbulence from the cloud radar, the uncertainties in the Doppler wind retrieval have to be taken into account, such as the variance of hydrometeor fall speed and the contamination of vertical Doppler velocity by the horizontal wind. A thorough analysis of the uncertainties shows that 25% accuracy or better can be achieved in regions of moderate to severe turbulence in the lee of the mountains, while only qualitative estimates of turbulence intensity can be obtained outside the most turbulent regions. Two NASA06 events exhibiting large-amplitude mountain waves, mid-tropospheric wave breaking, and rotor circulations are examined. Moderate turbulence is found in a wave-breaking region with σw2 and EDR reaching 4.8 m(2) s(-2) and 0.25 m(2/3) s(-1), respectively. Severe turbulence is measured within the rotor circulations with σw2 and EDR respectively in the ranges of 7.8-16.4 m(2) s(-2) and 0.50-0.77 m(2/3) s(-1). A unique result of this study is the quantitative estimation of the intensity of turbulence and its spatial distribution in the interior of atmospheric rotors, provided by the radar-derived turbulence fields.

  10. In Situ Neutron Diffraction Measurements During Annealing of Deformed Beryllium With Differing Initial Textures

    NASA Astrophysics Data System (ADS)

    Brown, Donald W.; Clausen, B.; Sisneros, T. A.; Balogh, L.; Beyerlein, I. J.

    2013-12-01

    The recovery of deformed beryllium was studied with mechanical testing and in situ neutron diffraction measurements. The initial texture of the material and the deformation rate were manipulated to produce four distinct deformation microstructures. The dislocation density was determined from line profile analysis of the neutron diffraction data collected as a function of temperature during annealing to a maximum homologous temperature of 0.53 following deformation. Mechanical testing was completed after the in situ annealing to determine the extent of the recovery of the flow stress. Both the dislocation density and flow stress recovered significantly by a relatively low homologous temperature of 0.3. A comparison with model calculations using a dislocation-based hardening law indicates that it is forest-type dislocations that annihilate during the relatively low temperature anneal; the dislocation substructure was stable at these temperatures. Finally, the motion of the dislocations during annealing prevented the development of intergranular thermal stresses due to the crystallographically anisotropic thermal expansion of beryllium.

  11. In situ measurement of methane oxidation in groundwater by using natural-gradient tracer tests

    USGS Publications Warehouse

    Smith, R.L.; Howes, B.L.; Garabedian, S.P.

    1991-01-01

    Methane oxidation was measured in an unconfined sand and gravel aquifer (Cape Cod, Mass.) by using in situ natural-gradient tracer tests at both a pristine, oxygenated site and an anoxic, sewage-contaminated site. The tracer sites were equipped with multilevel sampling devices to create target grids of sampling points; the injectate was prepared with groundwater from the tracer site to maintain the same geochemical conditions. Methane oxidation was calculated from breakthrough curves of methane relative to halide and inert gas (hexafluoroethane) tracers and was confirmed by the appearance of 13C-enriched carbon dioxide in experiments in which 13C-enriched methane was used as the tracer. A V(max) for methane oxidation could be calculated when the methane concentration was sufficiently high to result in zero-order kinetics throughout the entire transport interval. Methane breakthrough curves could be simulated by modifying a one-dimensional advection-dispersion transport model to include a Michaelis-Menten-based consumption term for methane oxidation. The K(m) values for methane oxidation that gave the best match for the breakthrough curve peaks were 6.0 and 9.0 ??M for the uncontaminated and contaminated sites, respectively. Natural-gradient tracer tests are a promising approach for assessing microbial processes and for testing in situ bioremediation potential in groundwater systems.

  12. In-situ membrane hydration measurement of proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Lai, Yeh-Hung; Fly, Gerald W.; Clapham, Shawn

    2015-01-01

    Achieving proper membrane hydration control is one of the most critical aspects of PEM fuel cell development. This article describes the development and application of a novel 50 cm2 fuel cell device to study the in-situ membrane hydration by measuring the through-thickness membrane swelling via an array of linear variable differential transducers. Using this setup either as an air/air (dummy) cell or as a hydrogen/air (operating) cell, we performed a series of hydration and dehydration experiments by cycling the RH of the inlet gas streams at 80 °C. From the linear relationship between the under-the-land swelling and the over-the-channel water content, the mechanical constraint within the fuel cell assembly can suppress the membrane water uptake by 11%-18%. The results from the air/air humidity cycling test show that the membrane can equilibrate within 120 s for all RH conditions and that membrane can reach full hydration at a RH higher than 140% in spite of the use of a liquid water impermeable Carbel MP30Z microporous layer. This result confirms that the U.S. DOE's humidity cycling mechanical durability protocol induces sufficient humidity swings to maximize hygrothermal mechanical stresses. This study shows that the novel experimental technique can provide a robust and accurate means to study the in-situ hydration of thin membranes subject to a wide range of fuel cell conditions.

  13. In-situ temperature measurement in lithium ion battery by transferable flexible thin film thermocouples

    NASA Astrophysics Data System (ADS)

    Mutyala, Madhu Santosh K.; Zhao, Jingzhou; Li, Jianyang; Pan, Hongen; Yuan, Chris; Li, Xiaochun

    2014-08-01

    Temperature monitoring is important for improving the safety and performance of Lithium Ion Batteries (LIB). This paper presents the feasibility study to insert flexible polymer embedded thin film thermocouples (TFTCs) in a lithium ion battery pouch cell for in-situ temperature monitoring. A technique to fabricate polyimide embedded TFTC sensors on glass substrates and later transfer it onto thin copper foils is presented. The sensor transfer process can be easily integrated into the assembly process of a pouch cell, thus holding promise in implementing in Battery Management Systems (BMS). Internal temperature of the LIB pouch cell was measured in-situ when the sensor embedded battery was operated at high rate charge-discharge cycles. The polyimide embedded TFTCs survived the battery assembly process and the battery electrolyte environment. It is observed that the heat generation inside the battery is dominant during the high-rate of discharges. The developed technique can serve to improve the battery safety and performance when implemented in battery management systems and enhance the understanding of heat generation and its effects.

  14. In-situ measurements of Cu in an estuarine environment using a portable spectrophotometric analysis system.

    PubMed

    Callahan, Michael R; Kaltenbacher, Eric A; Byrne, Robert H

    2004-01-15

    Application of a portable in-situ spectrophotometric analysis system for the measurement of Cu in estuarine environments is described in this work. Our spectrophotometric elemental analysis system (SEAS) used for in-situ observations of Cu concentrations is capable of fully autonomous or user-controlled operations. The optical cells used in SEAS systems are flexible liquid core waveguides (LCWs) with optical path lengths as long as 5 m. The 1-m waveguide used in the present study provided a 3.0 nM detection limit and a 5.0% relative standard deviation for a 25 nM copper sample. Analysis times range between 1 and 5 min, allowing for acquisition of data on scales appropriate to the highly dynamic biogeochemical nature of copper in the coastal environment. Field deployments of SEAS-Cu in Tampa Bay, FL, showed low Cu concentrations near the mouth of the estuary (3-4 nM), with elevated concentrations (approximately 25 nM) in anthropogenically impacted regions of the bay (e.g., marinas and areas adjacent wastewater treatment plants). Transect data between Tampa Bay and a deep water harborage exhibited copper concentrations ranging between 5 and 50 nM.

  15. A rapid in situ respiration test for measuring aerobic biodegradation rates of hydrocarbons in soil

    SciTech Connect

    Hinchee, R.E.; Ong, S.K. )

    1992-10-01

    A in situ test method to measure the aerobic biodegradation rates of hydrocarbons in contaminated soil is presented. The test method provides an initial assessment of bioventing as a remediation technology for hydrocarbon-contaminated soil. The in situ respiration test consists of ventilating the contaminated soil of the unsaturated zone with air and periodically monitoring the depletion of oxygen (O[sub 2]) and production of carbon dioxide (CO[sub 2]) over time after the air is turned off. The test is simple to implement and generally takes about four to five days to complete. The test was applied at eight hydrocarbon-contaminated sites of different geological and climatic conditions. These sites were contaminated with petroleum products or petroleum fuels, except for two sites where the contaminants were primarily polycyclic aromatic hydrocarbons. Oxygen utilization rates for the eight sites ranged from 0.02 to 0.99 percent O[sub 2]/hour. Estimated biodegradation rates ranged from 0.4 to 19 mg/kg of soil/day. These rates were similar to the biodegradation rates obtained from field and pilot studies using mass balance methods. Estimated biodegradation rates based on O[sub 2] utilization were generally more reliable (especially for alkaline soils) than rates based on CO[sub 2] production, CO[sub 2] produced from microbial respiration was probably converted to carbonate under alkaline conditions. 14 refs., 5 figs., 4 tabs.

  16. A rapid in situ respiration test for measuring aerobic biodegradation rates of hydrocarbons in soil.

    PubMed

    Hinchee, R E; Ong, S K

    1992-10-01

    An in situ test method to measure the aerobic biodegradation rates of hydrocarbons in contaminated soil is presented. The test method provides an initial assessment of bioventing as a remediation technology for hydrocarbon-contaminated soil. The in situ respiration test consists of ventilating the contaminated soil of the unsaturated zone with air and periodically monitoring the depletion of oxygen (O2) and production of carbon dioxide (CO2) over time after the air is turned off. The test is simple to implement and generally takes about four to five days to complete. The test was applied at eight hydrocarbon-contaminated sites of different geological and climatic conditions. These sites were contaminated with petroleum products or petroleum fuels, except for two sites where the contaminants were primarily polycyclic aromatic hydrocarbons. Oxygen utilization rates for the eight sites ranged from 0.02 to 0.99 percent O2/hour. Estimated biodegradation rates ranged from 0.4 to 19 mg/kg of soil/day. These rates were similar to the biodegradation rates obtained from field and pilot studies using mass balance methods. Estimated biodegradation rates based on O2 utilization were generally more reliable (especially for alkaline soils) than rates based on CO2 production. CO2 produced from microbial respiration was probably converted to carbonate under alkaline conditions.

  17. A novel apparatus for in situ measurement of thermal conductivity of hydrate-bearing sediments

    NASA Astrophysics Data System (ADS)

    Zhao, Jiafei; Wang, Bin; Yang, Lei; Cheng, Chuanxiao; Song, Yongchen

    2015-08-01

    An experimental apparatus was developed to synthesize natural gas hydrates and measure the thermal conductivity of hydrate-bearing sediments in situ. The apparatus works over a temperature range varying from -20 °C to 50 °C and up to a maximum pressure of 20 MPa. This apparatus is mainly composed of a thermal conductivity test system and a reaction cell, into which a lab-fabricated thermistor probe is inserted. This thermistor has excellent temperature sensitivity and can work at high pressures. The basic principles of this apparatus are discussed, and a series of experiments were performed to verify that the apparatus can be practically applied in chemical engineering. The thermistor-based measuring method was applied successfully in a high-pressure environment both with and without porous media.

  18. Correction of large birefringent effect of windows for in situ ellipsometry measurements.

    PubMed

    Jin, Lianhua; Kondoh, Eiichi

    2014-03-15

    To extract true optical properties of samples in a chamber with entrance and exit optical windows, oftentimes the windows were approximated as simple retarders where the retardation was small and premeasured under a given condition. The proposed method allows to cope with large birefringent effect of chamber windows thanks to its capability of extracting ellipsometric parameters (Δ, Ψ) of isotropic samples as well as measuring birefringent parameters (δ, θ) of each window separately and simultaneously. This method is, however, not valid for anisotropic samples. Ex situ results and extracted ellipsometric parameters results from in situ measurements of a silicon substrate and a SiO2 film thermally grown on the silicon substrate exhibited excellent agreement and provided significance of this method.

  19. In Situ Frequency Measurement of Inidividual Nanostructures Using Fiber Optical Interferometry

    SciTech Connect

    Duden, Thomas; Duden, Thomas; Radmilovic, Velimir

    2008-07-01

    In this paper we describe a setup for the resonance frequency measurement of nanocantilevers, which displays both high spatial selectivity and sensitivity to specimen vibrations by utilizing a tapered uncoated fiber tip. The spatial selectivity is determined by the tip geometry, the high sensitivity to vibrations stems from interference of wave fronts reflected on the specimen and on the fiber tip itself. No reference plane on the specimen is needed, as demonstrated with the example of a freestanding silicon nitride cantilever. The resulting system is integrated in the DB-235 dual beam FIB system, thus allowing the measurement of sample responses in-situ, during observation in SEM mode. By combining optical interferometry and narrow band RF amplification and detection, we demonstrate an exceptional vibrational sensitivity at high spatial resolution.

  20. A novel apparatus for in situ measurement of thermal conductivity of hydrate-bearing sediments.

    PubMed

    Zhao, Jiafei; Wang, Bin; Yang, Lei; Cheng, Chuanxiao; Song, Yongchen

    2015-08-01

    An experimental apparatus was developed to synthesize natural gas hydrates and measure the thermal conductivity of hydrate-bearing sediments in situ. The apparatus works over a temperature range varying from -20 °C to 50 °C and up to a maximum pressure of 20 MPa. This apparatus is mainly composed of a thermal conductivity test system and a reaction cell, into which a lab-fabricated thermistor probe is inserted. This thermistor has excellent temperature sensitivity and can work at high pressures. The basic principles of this apparatus are discussed, and a series of experiments were performed to verify that the apparatus can be practically applied in chemical engineering. The thermistor-based measuring method was applied successfully in a high-pressure environment both with and without porous media.

  1. Comparison of in situ stratospheric ozone measurements obtained during the MAP/GLOBUS 1983 campaign

    NASA Technical Reports Server (NTRS)

    Aimedieu, P.; Matthews, W. A.; Attmannspacher, W.; Hartmannsgruber, R.; Cisneros, J.; Komhyr, W.; Robbins, D. E.

    1987-01-01

    Data from five types of in situ ozone sensors flown aboard ballons during the MAP/GLOBUS 1983 campaign were found to agree to within 5 percent uncertainty throughout the middle atmosphere. A description of the individual techniques and the error budget is given in addition to explanations for the discrepancies found at higher and lower altitudes. In comparison to UV photometry values, results from two electrochemical techniques were found to be greater in the lower atmosphere and to be lower in the upper atmosphere. In general, olefin chemiluminescence results were within 8 percent of the UV photometry results. Ozone column contents measured by the indigo colorization technique for two altitude regions of about 6 km height were greater than measurements from other techniques by 52 and 17 percent, respectively.

  2. Chromosome translocations measured by fluorescence in-situ hybridization: A promising biomarker

    SciTech Connect

    Lucas, J.N.; Straume, T.

    1995-10-01

    A biomarker for exposure and risk assessment would be most useful if it employs an endpoint that is highly quantitative, is stable with time, and is relevant to human risk. Recent advances in chromosome staining using fluorescence in situ hybridization (FISH) facilitate fast and reliable measurement of reciprocal translocations, a kind of DNA damage linked to both prior exposure and risk. In contrast to other biomarkers available, the frequency of reciprocal translocations in individuals exposed to whole-body radiation is stable with time post exposure, has a rather small inter-individual variability, and can be measured accurately at the low levels. Here, the authors discuss results from their studies demonstrating that chromosome painting can be used to reconstruct radiation dose for workers exposed within the dose limits, for individuals exposed a long time ago, and even for those who have been diagnosed with leukemia but not yet undergone therapy.

  3. Time-resolved in-situ measurement of mitochondrial malfunction by energy transfer spectroscopy

    NASA Astrophysics Data System (ADS)

    Schneckenburger, Herbert; Gschwend, Michael H.; Strauss, Wolfgang S. L.; Sailer, Reinhard; Schoch, Lars; Schuh, Alexander; Stock, Karl; Steiner, Rudolf W.; Zipfl, Peter

    1999-07-01

    To establish optical in situ detection of mitochondrial malfunction, non-radiative energy transfer from the coenzyme NADH to the mitochondrial marker rhodamine 123 (R123) was examined. Dual excitation of R123 via energy transfer from excited NADH molecules as well as by direct absorption of light results in two fluorescence signals whose ratio is a measure of mitochondrial NADH. An experimental setup was developed, where these signals are detected simultaneously using a time-gated technique for energy transfer measurements and a frequency selective technique for direct excitation and fluorescence monitoring of R123. Optical and electronic components of the apparatus are described, and preliminary result of cultivated endothelial cells are reported. Results are compared with those obtained from a previously established microscopic system and discussed in view of potential applications.

  4. Versatile variable temperature insert at the DEIMOS beamline for in situ electrical transport measurements.

    PubMed

    Joly, L; Muller, B; Sternitzky, E; Faullumel, J G; Boulard, A; Otero, E; Choueikani, F; Kappler, J P; Studniarek, M; Bowen, M; Ohresser, P

    2016-05-01

    The design and the first experiments are described of a versatile cryogenic insert used for its electrical transport capabilities. The insert is designed for the cryomagnet installed on the DEIMOS beamline at the SOLEIL synchrotron dedicated to magnetic characterizations through X-ray absorption spectroscopy (XAS) measurements. This development was spurred by the multifunctional properties of novel materials such as multiferroics, in which, for example, the magnetic and electrical orders are intertwined and may be probed using XAS. The insert thus enables XAS to in situ probe this interplay. The implementation of redundant wiring and careful shielding also enables studies on operating electronic devices. Measurements on magnetic tunnel junctions illustrate the potential of the equipment toward XAS studies of in operando electronic devices.

  5. Investigation of in-situ measurement of pollutant gases over Penang island

    NASA Astrophysics Data System (ADS)

    Tan, C. H.; Tan, F.; Beh, B. C.; Mat Jafri, M. Z.; Lim, H. S.

    2013-05-01

    Penang Island is experiencing rapid development in house construction and industrial activity which caused air pollution problems getting worst. Furthermore, with recent forest burning in Indonesia, the situation was become serious. Due to the increasing in air pollution problems, we decided to carry out an investigation of air pollution over Penang Island. In this paper, we used Aeroqual Series 500 Monitor (for NO2 and O3) and MultiRAE-IR Model PGM-54 (for CO2) to perform in-situ ground level measurement over Penang Island. All measurement has been carried out every 5km journey around the Penang Island. From the data obtained, the changes of NO2, O3 and CO2 pollutant gasses concentration over time can be study and further investigate.

  6. The first in situ electron temperature and density measurements of the Martian nightside ionosphere

    NASA Astrophysics Data System (ADS)

    Fowler, C. M.; Andersson, L.; Ergun, R. E.; Morooka, M.; Delory, G.; Andrews, D. J.; Lillis, Robert J.; McEnulty, T.; Weber, T. D.; Chamandy, T. M.; Eriksson, A. I.; Mitchell, D. L.; Mazelle, C.; Jakosky, B. M.

    2015-11-01

    The first in situ nightside electron density and temperature profiles at Mars are presented as functions of altitude and local time (LT) from the Langmuir Probe and Waves (LPW) instrument on board the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission spacecraft. LPW is able to measure densities as low as ˜100 cm-3, a factor of up to 10 or greater improvement over previous measurements. Above 200 km, near-vertical density profiles of a few hundred cubic centimeters were observed for almost all nightside LT, with the lowest densities and highest temperatures observed postmidnight. Density peaks of a few thousand cubic centimeters were observed below 200 km at all nightside LT. The lowest temperatures were observed below 180 km and approach the neutral atmospheric temperature. One-dimensional modeling demonstrates that precipitating electrons were able to sustain the observed nightside ionospheric densities below 200 km.

  7. In Situ Thermal Ion Temperature Measurements in the E Region Ionosphere: Techniques, Results, and Limitations

    NASA Astrophysics Data System (ADS)

    Burchill, J. K.; Archer, W. E.; Clemmons, J. H.; Knudsen, D. J.; Nicolls, M. J.

    2011-12-01

    In situ measurements of thermal ion temperature are rare at E region altitudes, which are too low for satellites. Here we present ion temperature measurements from a Thermal Ion Imager (TII) that flew on NASA sounding rocket 36.234 (the "Joule-2" mission) into the nightside E region ionosphere on 19 January 2007 from Poker Flat, AK. The TII is an electrostatic ion energy/angle imager that provides 2D ion distributions at 8 ms resolution. Ion temperatures are derived at altitudes between 100 km and 190 km by modelling the detector total count rate versus ion bulk flow angle with respect to the plane of the imager's field of view. Modelling this count rate spin profile shows that the analysis technique is robust against a number of error sources, including variability in payload floating potential, ion upflow, and aperture widening due to reflections from electrode surfaces. A significant uncertainty is associated with the average mass of the ions, which is not measured independently. Using the International Reference Ionosphere model to estimate ion mass, we obtain an ion temperature of 1300 K at 125 km, increasing to more than 3000 K at 180 km. These temperatures are much larger than neutral temperatures obtained from an ionization gauge on the same rocket (Tn˜500 K at 125 km, ˜600 K at 180 km), and do not agree with incoherent scatter radar observations in the vicinity of the rocket. These anomalous ion temperatures are, however, consistent with results from an independent analysis of the shape of the ion distribution images from a similar instrument on a separate payload flown 10 minutes earlier [Archer, MSc Thesis, University of Calgary, 2009]. We conclude that the high ion temperature readings are an artifact related to the environment in the vicinity of the probe, and investigate mechanisms for the cause. We discuss the implications of this effect for future in situ attempts to measure ion temperature in the E region ionosphere.

  8. Comparison of in-situ measurements and satellite-derived surface emissivity over Italian volcanic areas

    NASA Astrophysics Data System (ADS)

    Silvestri, Malvina; Musacchio, Massimo; Cammarano, Diego; Fabrizia Buongiorno, Maria; Amici, Stefania; Piscini, Alessandro

    2016-04-01

    In this work we compare ground measurements of emissivity collected during dedicated fields campaign on Mt. Etna and Solfatara of Pozzuoli volcanoes and acquired by means of Micro-FTIR (Fourier Thermal Infrared spectrometer) instrument with the emissivity obtained by using single ASTER data (Advanced Spaceborne Thermal Emission and Reflection Radiometer, ASTER 05) and the ASTER emissivity map extract from ASTER Global Emissivity Database (GED), released by LP DAAC on April 2, 2014. The database was developed by the National Aeronautics and Space Administration's (NASA) Jet Propulsion Laboratory (JPL), California Institute of Technology. The database includes land surface emissivity derived from ASTER data acquired over the contiguous United States, Africa, Arabian Peninsula, Australia, Europe, and China. Through this analysis we want to investigate the differences existing between the ASTER-GED dataset (average from 2000 to 2008 seasoning independent) and fall in-situ emissivity measurement. Moreover the role of different spatial resolution characterizing ASTER and MODIS, 90mt and 1km respectively, by comparing them with in situ measurements, is analyzed. Possible differences can be due also to the different algorithms used for the emissivity estimation, Temperature and Emissivity Separation algorithm for ASTER TIR band( Gillespie et al, 1998) and the classification-based emissivity method (Snyder and al, 1998) for MODIS. Finally land surface temperature products generated using ASTER-GED and ASTER 05 emissivity are also analyzed. Gillespie, A. R., Matsunaga, T., Rokugawa, S., & Hook, S. J. (1998). Temperature and emissivity separation from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) images. IEEE Transactions on Geoscience and Remote Sensing, 36, 1113-1125. Snyder, W.C., Wan, Z., Zhang, Y., & Feng, Y.-Z. (1998). Classification-based emissivity for land surface temperature measurement from space. International Journal of Remote Sensing, 19

  9. Evapotranspiration partitioning through in-situ oxygen isotope measurements in an oasis cropland

    NASA Astrophysics Data System (ADS)

    Wen, Xue-Fa

    2016-04-01

    The oxygen isotope compositions of ecosystem water pools and fluxes are useful tracers in the water cycle. As part of the Heihe Watershed Allied Telemetry Experimental Research (HiWATER) program, high-frequency and near-continuous in situ measurements of 18O composition of atmospheric vapor (δv) and of evapotranspiration (δET) were made with the flux-gradient method using a cavity ring-down spectroscopy water vapor isotope analyzer. At the sub-daily scale, we found, in conjunction with intensive isotopic measurements of other ecosystem water pools, that the differences between 18O composition of transpiration (δT) and of xylem water (δx) were negligible in early afternoon (13:00-15:00 Beijing time) when ET approached the daytime maximum, indicating isotopic steady state. At the daily scale, for the purpose of flux partitioning, δT was approximated by δx at early afternoon hours, and the 18O composition of soil evaporation (δE) was obtained from the Craig-Gordon model with a moisture-dependent soil resistance. The relative contribution of transpiration to evapotranspiration ranged from 0.71 to 0.96 with a mean of 0.87 ± 0.052 for the growing season according to the isotopic labeling, which was good agreement with soil lysimeter measurements showing a mean transpiration fraction of 0.86 ± 0.058. At the growing season scale, the predicted18O composition of runoff water was within the range of precipitation and irrigation water according to the isotopic mass conservation. The 18O mass conservation requires that the decreased δ18O of ET should be balanced by enhanced δ18O of runoff water. (Wen, XF*, Yang, B, Sun, XM, Lee, X. 2015. Evapotranspiration partitioning through in-situ oxygen isotope measurements in an oasis cropland. Agricultural and Forest Meteorology , doi:10.1016/j.agrformet.2015.12.003).

  10. Mars dayside temperature from airglow limb profiles : comparison with in situ measurements and models

    NASA Astrophysics Data System (ADS)

    Gérard, Jean-Claude; Bougher, Stephen; Montmessin, Franck; Bertaux, Jean-Loup; Stiepen, A.

    The thermal structure of the Mars upper atmosphere is the result of the thermal balance between heating by EUV solar radiation, infrared heating and cooling, conduction and dynamic influences such as gravity waves, planetary waves, and tides. It has been derived from observations performed from different spacecraft. These include in situ measurements of orbital drag whose strength depends on the local gas density. Atmospheric temperatures were determined from the altitude variation of the density measured in situ by the Viking landers and orbital drag measurements. Another method is based on remote sensing measurements of ultraviolet airglow limb profiles obtained over 40 years ago with spectrometers during the Mariner 6 and 7 flybys and from the Mariner 9 orbiter. Comparisons with model calculations indicate that they both reflect the CO_2 scale height from which atmospheric temperatures have been deduced. Upper atmospheric temperatures varying over the wide range 270-445 K, with a mean value of 325 K were deduced from the topside scale height of the airglow vertical profile. We present an analysis of limb profiles of the CO Cameron (a(3) Pi-X(1) Sigma(+) ) and CO_2(+) doublet (B(2) Sigma_u(+) - X(2) PiΠ_g) airglows observed with the SPICAM instrument on board Mars Express. We show that the temperature in the Mars thermosphere is very variable with a mean value of 270 K, but values ranging between 150 and 400 K have been observed. These values are compared to earlier determinations and model predictions. No clear dependence on solar zenith angle, latitude or season is apparent. Similarly, exospheric variations with F10.7 in the SPICAM airglow dataset are small over the solar minimum to moderate conditions sampled by Mars Express since 2005. We conclude that an unidentified process is the cause of the large observed temperature variability, which dominates the other sources of temperature variations.

  11. In-Situ Measurement of Hall Thruster Erosion Using a Fiber Optic Regression Probe

    NASA Technical Reports Server (NTRS)

    Polzink, Kurt A.; Korman, Valentin

    2008-01-01

    One potential life-limiting mechanism in a Hall thruster is the erosion of the ceramic material comprising the discharge channel. This is especially true for missions that require long thrusting periods and can be problematic for lifetime qualification, especially when attempting to qualify a thruster by analysis rather than a test lasting the full duration of the mission. In addition to lifetime, several analytical and numerical models include electrode erosion as a mechanism contributing to enhanced transport properties. However, there is still a great deal of dispute over the importance of erosion to transport in Hall thrusters. The capability to perform an in-situ measurement of discharge channel erosion is useful in addressing both the lifetime and transport concerns. An in-situ measurement would allow for real-time data regarding the erosion rates at different operating points, providing a quick method for empirically anchoring any analysis geared towards lifetime qualification. Erosion rate data over a thruster's operating envelope would also be useful in the modeling of the detailed physics inside the discharge chamber. A recent fundamental sensor development effort has led to a novel regression, erosion, and ablation sensor technology (REAST). The REAST sensor allows for measurement of real-time surface erosion rates at a discrete surface location. The sensor was tested using a linear Hall thruster geometry, which served as a means of producing plasma erosion of a ceramic discharge chamber. The mass flow rate, discharge voltage, and applied magnetic field strength could be varied, allowing for erosion measurements over a broad thruster operating envelope. Results are presented demonstrating the ability of the REAST sensor to capture not only the insulator erosion rates but also changes in these rates as a function of the discharge parameters.

  12. Airborne Sunphotometer Studies of Aerosol Properties and Effects, Including Closure Among Satellite, Suborbital Remote, and In situ Measurements

    NASA Technical Reports Server (NTRS)

    Russlee, Philip B.; Schmid, B.; Redemann, J.; Livingston, J. M.; Bergstrom, R. W.; Ramirez, S. A.; Hipskind, R. Stephen (Technical Monitor)

    2001-01-01

    Airborne sunphotometry has been used to measure aerosols from North America, Europe, and Africa in coordination with satellite and in situ measurements in TARFOX (1996), ACE-2 (1997), PRIDE (2000), and SAFARI 2000. Similar coordinated measurements of Asian aerosols are being conducted this spring in ACE-Asia and are planned for North American aerosols this summer in CLAMS. This paper summarizes the approaches used, key results, and implications for aerosol properties and effects, such as single scattering albedo and regional radiative forcing. The approaches exploit the three-dimensional mobility of airborne sunphotometry to access satellite scenes over diverse surfaces (including open ocean with and without sunglint) and to match exactly the atmospheric layers sampled by airborne in situ measurements and other radiometers. These measurements permit tests of the consistency, or closure, among such diverse measurements as aerosol size-resolved chemical composition; number or mass concentration; light extinction, absorption, and scattering (total, hemispheric back and 180 deg.); and radiative fluxes. In this way the airborne sunphotometer measurements provide a key link between satellite and in situ measurements that helps to understand any discrepancies that are found. These comparisons have led to several characteristic results. Typically these include: (1) Better agreement among different types of remote measurements than between remote and in situ measurements. (2) More extinction derived from transmission measurements than from in situ measurements. (3) Larger aerosol absorption inferred from flux radiometry than from in situ measurements. Aerosol intensive properties derived from these closure studies have been combined with satellite-retrieved fields of optical depth to produce fields of regional radiative forcing. We show results for the North Atlantic derived from AVHRR optical depths and aerosol intensive properties from TARFOX and ACE-2. Companion papers

  13. Improved Beam Diagnostic Spatial Calibration Using In-Situ Measurements of Beam Emission

    NASA Astrophysics Data System (ADS)

    Chrystal, C.; Burrell, K. H.; Pace, D. C.; Grierson, B. A.; Pablant, N. A.

    2014-10-01

    A new technique has been developed for determining the measurement geometry of the charge exchange recombination spectroscopy diagnostic (CER) on DIII-D. This technique removes uncertainty in the measurement geometry related to the position of the neutral beams when they are injecting power. This has been accomplished by combining standard measurements that use in-vessel calibration targets with spectroscopic measurements of Doppler shifted and Stark split beam emission to fully describe the neutral beam positions and CER views. A least squares fitting routine determines the measurement geometry consistent with all the calibration data. The use of beam emission measurements allows the position of the neutral beams to be determined in-situ by the same views that makeup the CER diagnostic. Results indicate that changes in the measurement geometry are required to create a consistent set of calibration measurements. However, changes in quantities derived from the geometry, e.g. ion temperature gradient and poloidal rotation, are small. Work supported by the US DOE under DE-FG02-07ER54917, DE-FC02-04ER54698, and DE-AC02-09H11466.

  14. Using STOQS and stoqstoolbox for in situ Measurement Data Access in Matlab

    NASA Astrophysics Data System (ADS)

    López-Castejón, F.; Schlining, B.; McCann, M. P.

    2012-12-01

    This poster presents the stoqstoolbox, an extension to Matlab that simplifies the loading of in situ measurement data directly from STOQS databases. STOQS (Spatial Temporal Oceanographic Query System) is a geospatial database tool designed to provide efficient access to data following the CF-NetCDF Discrete Samples Geometries convention. Data are loaded from CF-NetCDF files into a STOQS database where indexes are created on depth, spatial coordinates and other parameters, e.g. platform type. STOQS provides consistent, simple and efficient methods to query for data. For example, we can request all measurements with a standard_name of sea_water_temperature between two times and from between two depths. Data access is simpler because the data are retrieved by parameter irrespective of platform or mission file names. Access is more efficient because data are retrieved via the index on depth and only the requested data are retrieved from the database and transferred into the Matlab workspace. Applications in the stoqstoolbox query the STOQS database via an HTTP REST application programming interface; they follow the Data Access Object pattern, enabling highly customizable query construction. Data are loaded into Matlab structures that clearly indicate latitude, longitude, depth, measurement data value, and platform name. The stoqstoolbox is designed to be used in concert with other tools, such as nctoolbox, which can load data from any OPeNDAP data source. With these two toolboxes a user can easily work with in situ and other gridded data, such as from numerical models and remote sensing platforms. In order to show the capability of stoqstoolbox we will show an example of model validation using data collected during the May-June 2012 field experiment conducted by the Monterey Bay Aquarium Research Institute (MBARI) in Monterey Bay, California. The data are available from the STOQS server at http://odss.mbari.org/canon/stoqs_may2012/query/. Over 14 million data points of

  15. Mercury dynamics in a San Francisco estuary tidal wetland: assessing dynamics using in situ measurements

    USGS Publications Warehouse

    Bergamaschi, Brian A.; Fleck, Jacob A.; Downing, Bryan D.; Boss, Emmanuel; Pellerin, Brian A.; Ganju, Neil K.; Schoellhamer, David H.; Byington, Amy A.; Heim, Wesley A.; Stephenson, Mark; Fujii, Roger

    2012-01-01

    We used high-resolution in situ measurements of turbidity and fluorescent dissolved organic matter (FDOM) to quantitatively estimate the tidally driven exchange of mercury (Hg) between the waters of the San Francisco estuary and Browns Island, a tidal wetland. Turbidity and FDOM—representative of particle-associated and filter-passing Hg, respectively—together predicted 94 % of the observed variability in measured total mercury concentration in unfiltered water samples (UTHg) collected during a single tidal cycle in spring, fall, and winter, 2005–2006. Continuous in situ turbidity and FDOM data spanning at least a full spring-neap period were used to generate UTHg concentration time series using this relationship, and then combined with water discharge measurements to calculate Hg fluxes in each season. Wetlands are generally considered to be sinks for sediment and associated mercury. However, during the three periods of monitoring, Browns Island wetland did not appreciably accumulate Hg. Instead, gradual tidally driven export of UTHg from the wetland offset the large episodic on-island fluxes associated with high wind events. Exports were highest during large spring tides, when ebbing waters relatively enriched in FDOM, dissolved organic carbon (DOC), and filter-passing mercury drained from the marsh into the open waters of the estuary. On-island flux of UTHg, which was largely particle-associated, was highest during strong winds coincident with flood tides. Our results demonstrate that processes driving UTHg fluxes in tidal wetlands encompass both the dissolved and particulate phases and multiple timescales, necessitating longer term monitoring to adequately quantify fluxes.

  16. Status Report of Development of a Sensor for In-Situ Space Dust Measurement

    NASA Astrophysics Data System (ADS)

    Kitazawa, Yukihito; Matsumoto, Haruhisa; Sakurai, Akira; Funakoshi, Kunihiro; Yasaka, Tesuo; Hanada, Toshiya; Hasegawa, Sunao

    2010-05-01

    The importance of measuring dust particles (larger than 100 μm) has increased, especially from engineering viewpoints (e.g. space system design and operations). However, it is difficult to measure the impact flux of these large particles because of the low spatial density of large particles (larger than 100 μm). Sensor systems to monitor these sizes must have a large detection area, while the constraints of a space environment deployment require that these systems be low in mass, low in power, robust and have low telemetry requirements. The in-situ measurement data are useful for; 1) verifications of meteoroid and debris environment models, 2) verifications of meteoroid and debris environment evolution models, 3) real time detection of unexpected events, such as explosions on an orbit (Ex. ASAT: Anti Satellite Test). JAXA has been developing a simple in-situ sensor to detect dust particles ranging from a hundred micrometers to several millimeters. Multitudes of thin, conductive strips are formed with fine pitch on a thin film of nonconductive material. A dust particle impact is detected when one or more strips are severed by the impact hole. The sensor is simple to produce and use and requires almost no calibration as it is essentially a digital system. The authors have developed prototypes of the sensors and performed hypervelocity impact experiments. As a result, prototype models have been manufactured successfully and the projectile diameter (debris diameter) is able to be estimated from the number of broken strips.This presentation reports the development status and actual flight plans of the sensor.

  17. Status Report of Development of a Sensor for In-Situ Space Dust Measurement

    NASA Astrophysics Data System (ADS)

    Kitazawa, Yukihito; Matsumoto, Haruhisa; Sakurai, Akira; Yasaka, Tetsuo; Funakoshi, Kunihiro; Hanada, Toshiya; Hasegawa, Sunao; Kadono, Toshihiko

    The importance of measuring dust particles (larger than 100 m) has increased, especially from engineering viewpoints (e.g. space system design and operations). However, it is difficult to measure the impact flux of these large particles because of the low spatial density of large par-ticles (larger than 100 m). Sensor systems to monitor these sizes must have a large detection area, while the constraints of a space environment deployment require that these systems be low in mass, low in power, robust and have low telemetry requirements. The in-situ measurement data are useful for; 1) verifications of meteoroid and debris environment models, 2) verifications of meteoroid and debris environment evolution models, 3) real time detection of unexpected events, such as explosions on an orbit (Ex.ASAT: Anti Satellite Test). JAXA has been devel-oping a simple in-situ sensor to detect dust particles ranging from a hundred micrometers to several millimeters. Multitudes of thin, conductive strips are formed with fine pitch on a thin film of nonconductive material. A dust particle impact is detected when one or more strips are severed by the impact hole. The sensor is simple to produce and use and requires almost no calibration as it is essentially a digital system. The authors have developed prototypes of the sensors and performed hypervelocity impact experiments. As a result, prototype models have been manufactured successfully and the projectile diameter (debris diameter) is able to be estimated from the number of broken strips.This presentation reports the development status and actual flight plans of the sensor.

  18. A miniature all-solid-state calcium electrode applied to in situ seawater measurement

    NASA Astrophysics Data System (ADS)

    Xu, Hui; Wang, You; Luo, Zhiyuan; Pan, Yiwen

    2013-12-01

    An all-solid-state miniature calcium ion selective electrode (ISE) based on poly(3,4-ethylenedioxythiophene) doped with poly(styrene sulfonate) (PEDOT(PSS)) for continuous in situ measurement in seawater was studied. The electrode substrate was a platinum (Pt) wire of 0.5 mm diameter and PEDOT(PSS) was electropolymerized on one end of the Pt wire to act as the solid contact of this calcium ISE. The PEDOT(PSS) layer was covered with a calcium-selective poly(vinyl chloride) membrane, which contained ETH129 as calcium ionophore, potassium tetrakis-(p-chlorophenyl)borate as lipophilic anion and bis(2-ethylhexyl) sebacate as the plasticizer. Experiments using electrochemical impedance spectroscopy and reversed chronopotentiometry illustrated that electropolymerized PEDOT(PSS) decreased the resistance and improved the stability of the electrode. The sensors can work stably in the calcium ion concentration range of 10-6-10-1 mol L-1 with the slope of 27.7 mV/decade. Also Na+, K+ and Mg2+ can hardly interfere with the performance of the electrode. This electrode was applied to measure the calcium ion concentration of seawater samples. The experimental data showed that the electrode can resist the corrosion of seawater and its reproducibility was good (SD < 0.1 mM kg-1). The lifetime of such an electrode was at least six months. Because of the wire-shape and the small size of such a liquid junction free calcium electrode, it is pressure-resistant and easy to package and seal, therefore it is suitable for use in underwater equipment for in situ seawater measurement.

  19. Focused beam reflectance measurement as a tool for in situ monitoring of the lactose crystallization process.

    PubMed

    Pandalaneni, K; Amamcharla, J K

    2016-07-01

    Lactose accounts for about 75 and 85% of the solids in whey and deproteinized whey, respectively. Production of lactose is usually carried out by a process called crystallization. Several factors including rate of cooling, presence of impurities, and mixing speed influence the crystal size characteristics. To optimize the lactose crystallization process parameters to maximize the lactose yield, it is important to monitor the crystallization process. However, efficient in situ tools to implement at concentrations relevant to the dairy industry are lacking. The objective of the present work was to use a focused beam reflectance measurement (FBRM) system for in situ monitoring of lactose crystallization at supersaturated concentrations (wt/wt) 50, 55, and 60% at 20 and 30°C. The FBRM data were compared with Brix readings collected using a refractometer during isothermal crystallization. Chord length distributions obtained from FBRM in the ranges of <50 µm (fine crystals) and 50 to 300 µm (coarse crystals) were recorded and evaluated in relation to the extent of crystallization and rate constants deduced from the refractometer measurements. Extent of crystallization and rate constants increased with increasing supersaturation concentration and temperature. The measured fine crystal counts from FBRM increased at higher supersaturated concentration and temperature during isothermal crystallization. On the other hand, coarse counts were observed to increase with decreasing supersaturated concentration and temperature. Square weighted chord length distribution obtained from FBRM showed that as concentration increased, a decrease in chord lengths occurred at 20°C and similar observations were made from microscopic images. The robustness of FBRM in understanding isothermal lactose crystallization at various concentrations and temperatures was successfully assessed in the study.

  20. Galileo In-Situ Dust Measurements and the Physics of Jupiter's Gossamer Rings

    NASA Astrophysics Data System (ADS)

    Krueger, H.; Hamilton, D. P.; Moissl, R.; Gruen, E.

    2007-12-01

    During its late orbital mission about Jupiter, the Galileo spacecraft flew twice through the giant planet's gossamer ring system. The dusty ring material is produced when interplanetary impactors collide with embedded moonlets. Optical images imply that the rings are constrained both horizontally and vertically by the orbits of the moons Amalthea and Thebe with the exception of a faint outward protrusion called the Thebe Extension. During the ring passages, the Galileo impact-ionization dust detector counted a few thousand impacts but only about 100 complete data sets of dust impacts (i.e. impact time, impact speed, mass, impact direction, etc.) were successfully transmitted to Earth. The instrument verified the outward extension of the gossamer ring beyond Thebe's orbit and measured a major reduction in particle ring material interior to Thebe's orbit. The existence of this partially evacuated gap in ring material is also indirectly confirmed by Galileo in-situ energetic particle measurements (Norbert Krupp, priv. comm.). Detected particle sizes range from about 0.2 to 4 micron, extending the size distribution by an order of magnitude towards smaller particles than previously derived from optical imaging (Showalter et al., Icarus 2007). The grain size distribution increases towards smaller grains, showing a much higher proportion of small particles in the Amalthea gossamer ring than in the Thebe ring and the Thebe Extension. Our analysis shows that particles contributing most to the optical cross-section are about 4 micron in radius, in agreement with imaging results. Finally, Galileo also detected some micron and sub-micron grains on highly inclined orbits with inclinations up to 20 degrees. Recent modelling (Hamilton & Krueger, Nature, submitted) shows that time variable electromagnetic effects can account for all of these surprising results. In particular, when the ring particles travel through Jupiter's shadow, dust grain electric charges vary systematically

  1. Water quality monitoring of Al-Habbaniyah Lake using remote sensing and in situ measurements.

    PubMed

    Al-Fahdawi, Ahmed A H; Rabee, Adel M; Al-Hirmizy, Shaheen M

    2015-06-01

    The use of remote sensing and GIS in water monitoring and management has been long recognized. This paper, however discusses the application of remote sensing and GIS specifically in monitoring water quality parameters in Al-Habbaniyah Lake, and the results were compared with in situ measurements. Variations of different parameters under investigation were as follows: temperature (15-33°C), pH (7-9), dissolved oxygen (6-11 mg/L), BOD5 (0.5-1.8), electrical conductivity (200-2280 μS/cm), TDS (147-1520 mg/L), TSS (68-3200), turbidity (5-51), nitrate (0.7-20 mg/l), phosphate (77-220 μg/l), and chlorophyll-a (0.9-130 μg/l). Remote sensing results revealed that the band 5 was most likely significantly correlated with turbidity in the winter. Band 2 and 3 was most likely significantly correlated with TDS in autumn and summer, while band 2 was most likely significantly correlated with TSS in autumn, band 2 is most likely significantly correlated with chlorophyll-a in autumn. The current study results demonstrated convergence between in situ and remote sensing readings. The models were used to explore the values of each of chlorophyll-a, TSS,TDS, and turbidity did not deviate much from the values actually measured in the three seasons. Nevertheless, they were very useful in anticipating all seasons of the study due to the insignificant deviation between the remotely sensed values and actual measured values.

  2. Comparison of vertical aerosol extinction coefficients from in-situ and LIDAR measurements

    NASA Astrophysics Data System (ADS)

    Rosati, B.; Herrmann, E.; Bucci, S.; Fierli, F.; Cairo, F.; Gysel, M.; Tillmann, R.; Größ, J.; Gobbi, G. P.; Di Liberto, L.; Di Donfrancesco, G.; Wiedensohler, A.; Weingartner, E.; Virtanen, A.; Mentel, T. F.; Baltensperger, U.

    2015-07-01

    Vertical profiles of aerosol optical properties were explored in a case study near the San Pietro Capofiume (SPC) ground station during the PEGASOS Po Valley campaign in the summer of 2012. A Zeppelin NT airship was employed to investigate the effect of the dynamics of the planetary boundary layer at altitudes between ~ 50-800 m above ground. Determined properties included the aerosol size distribution, the hygroscopic growth factor, the effective index of refraction and the light absorption coefficient. The first three parameters were used to retrieve the light scattering coefficient. Simultaneously, direct measurements of both the scattering and absorption coefficient were carried out at the SPC ground station. Additionally, a LIDAR system provided aerosol extinction coefficients for a vertically resolved comparison between in-situ and remote sensing results. First, the airborne results at low altitudes were validated with the ground measurements. Agreement within approximately ±25 and ±20% was found for the dry scattering and absorption coefficient, respectively. The single scattering albedo, ranged between 0.83 to 0.95, indicating the importance of the absorbing particles in the Po Valley region. A clear layering of the atmosphere was observed during the beginning of the flight (until ~ 10 local time) before the mixed layer (ML) was fully developed. Highest extinction coefficients were found at low altitudes, in the new ML, while values in the residual layer, which could be probed at the beginning of the flight at elevated altitudes, were lower. At the end of the flight (after ~ 12 local time) the ML was fully developed, resulting in constant extinction coefficients at all altitudes measured on the Zeppelin NT. LIDAR results captured these dynamic features well and good agreement was found for the extinction coefficients compared to the in-situ results, using fixed LIDAR ratios (LR) between 30 and 70 sr for the altitudes probed with the Zeppelin. These LR are

  3. In situ measurement of atmospheric krypton and xenon on Mars with Mars Science Laboratory

    NASA Astrophysics Data System (ADS)

    Conrad, P. G.; Malespin, C. A.; Franz, H. B.; Pepin, R. O.; Trainer, M. G.; Schwenzer, S. P.; Atreya, S. K.; Freissinet, C.; Jones, J. H.; Manning, H.; Owen, T.; Pavlov, A. A.; Wiens, R. C.; Wong, M. H.; Mahaffy, P. R.

    2016-11-01

    Mars Science Laboratory's Sample Analysis at Mars (SAM) investigation has measured all of the stable isotopes of the heavy noble gases krypton and xenon in the martian atmosphere, in situ, from the Curiosity Rover at Gale Crater, Mars. Previous knowledge of martian atmospheric krypton and xenon isotope ratios has been based upon a combination of the Viking mission's krypton and xenon detections and measurements of noble gas isotope ratios in martian meteorites. However, the meteorite measurements reveal an impure mixture of atmospheric, mantle, and spallation contributions. The xenon and krypton isotopic measurements reported here include the complete set of stable isotopes, unmeasured by Viking. The new results generally agree with Mars meteorite measurements but also provide a unique opportunity to identify various non-atmospheric heavy noble gas components in the meteorites. Kr isotopic measurements define a solar-like atmospheric composition, but deviating from the solar wind pattern at 80Kr and 82Kr in a manner consistent with contributions originating from neutron capture in Br. The Xe measurements suggest an intriguing possibility that isotopes lighter than 132Xe have been enriched to varying degrees by spallation and neutron capture products degassed to the atmosphere from the regolith, and a model is constructed to explore this possibility. Such a spallation component, however, is not apparent in atmospheric Xe trapped in the glassy phases of martian meteorites.

  4. 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.

  5. Aircraft measurement of electric field - Self-calibration

    NASA Technical Reports Server (NTRS)

    Winn, W. P.

    1993-01-01

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

  6. Comparison of Ice Cloud Particle Sizes Retrieved From Satellite Data Derived From In Situ Measurements

    NASA Technical Reports Server (NTRS)

    Han, Qingyuan; Rossow, William B.; Chou, Joyce; Welch, Ronald M.

    1997-01-01

    Cloud microphysical parameterizations have attracted a great deal of attention in recent years due to their effect on cloud radiative properties and cloud-related hydrological processes in large-scale models. The parameterization of cirrus particle size has been demonstrated as an indispensable component in the climate feedback analysis. Therefore, global-scale, long-term observations of cirrus particle sizes are required both as a basis of and as a validation of parameterizations for climate models. While there is a global scale, long-term survey of water cloud droplet sizes (Han et al. 1994), there is no comparable study for cirrus ice crystals. In this paper a near-global survey of cirrus ice crystal sizes is conducted using ISCCP satellite data analysis. The retrieval scheme uses phase functions based upon hexagonal crystals calculated by a ray tracing technique. The results show that global mean values of D(e) are about 60 micro-m. This study also investigates the possible reasons for the significant difference between satellite retrieved effective radii (approx. 60 micro-m) and aircraft measured particle sizes (approx. 200 micro-m) during the FIRE I IFO experiment. They are (1) vertical inhomogeneity of cirrus particle sizes; (2) lower limit of the instrument used in aircraft measurements; (3) different definitions of effective particle sizes; and (4) possible inappropriate phase functions used in satellite retrieval.

  7. Efficient coordination of swarms of sensor-laden balloons for persistent, in situ, real-time measurement of hurricane development*

    NASA Astrophysics Data System (ADS)

    Bewley, Thomas; Meneghello, Gianluca

    2016-10-01

    Accurate long-term forecasts of the path and intensity of severe hurricanes are imperative to protect property and save lives. Extensive real-time measurements within hurricanes, especially near their core, are essential for supplementing the limited relevant information accessible by satellites in order to improve such forecasts. Current operational methods for obtaining in situ information, such as dropsondes and repeated manned and unmanned aircraft flights over and within hurricanes, are both expensive and limited in duration. In the present work it is demonstrated by numerical experiments how a swarm of robust, inexpensive, buoyancy-controlled, sensor-laden balloons might be deployed and controlled in an energetically efficient, coordinated fashion, for days at a time, to continuously monitor relevant properties (pressure, humidity, temperature, and wind speed) of a hurricane as it develops. Rather than fighting its gale-force winds, the strong and predictable stratification of these winds is leveraged to efficiently disperse the balloons into a favorable time-evolving distribution. An iterative bootstrap approach is envisioned in which (a) sensor balloons are used to help improve the available computational estimate of the uncertain and underresolved flow field of the hurricane and (b) this (imprecise) estimate of the hurricane flow field is leveraged to improve the distribution of the sensor balloons, which then better facilitates (a), etc. The control approach envisioned in this ambitious effort is a combination of (centrally computed) model predictive control for coordination at the largest scales, which is the focus of the present paper, coupled with a feedback control strategy (decentrally computed, on the balloons themselves), for smaller-scale corrections. Our work indicates that, following such an approach, certain target orbits of interest within the hurricane can be continuously sampled by some balloons, while others make repeated sweeps between the

  8. Intercomparison of aerosol physical and physical properties derived from surface radiometers and in-situ aircraft profiles over six Maryland sites during the DRAGON and DISCOVER-AQ campaign

    NASA Astrophysics Data System (ADS)

    Schafer, J. S.; Thornhill, K. L.; Holben, B. N.; Anderson, B. E.; Eck, T. F.; Giles, D. M.; Winstead, E. L.; Ziemba, L. D.; Beyersdorf, A. J.; Smirnov, A.; Slutsker, I.; Sinyuk, A.; Kenny, P.

    2011-12-01

    The Aerosol Robotic Network (AERONET) project and international collaborators deployed more than 40 Cimel sunphotometers in the Baltimore-Washington, DC region for the summer 2011 DRAGON-USA (Distributed Regional Aerosol Gridded Observational Network) campaign. This unprecedented mesoscale network was comprised of automatic sun/sky radiometers distributed with roughly 10km grid spacing (covering an area of ~60km x 120km) which operated continuously for more than two months. The DRAGON-USA campaign was concurrent with the NASA sponsored DISCOVER-AQ air quality experiment which performed 14 days of research flights in July concentrating on repeated multiple daily profile measurements of gaseous and particulate pollution over 6 primary sun photometer sites. Atmospheric conditions varied from clean and dry to extremely hazy and humid on flight days with corresponding aerosol optical depth (AOD) at 500 nm ranging from ~0.06 to ~0.90 and precipitable water (PW) ranging from ~1.5 cm to ~4.5 cm. In-situ aerosol properties were measured on the NASA P-3B by the NASA Langley Aerosol Group Experiment (LARGE) team using a suite of instruments to characterize ambient aerosol optical and microphysical properties. Size distributions were made with a custom scanning mobility particle sizer (SMPS), an Ultrahigh Sensitivity Aerosol Spectrometer (UHSAS) from Droplet Measurement Technologies, and Aerosol Particle Sizer (APS) from TSI. Aerosol optical measurements were made with a TSI-3563 3-wavelength integrating nephelometer and a 3-wavelength Radiance Research Particle Soot Absorption Photometer (PSAP). We present preliminary comparisons of coincident single scattering albedo (at three wavelengths) and column integrated size distributions retrieved from the surface Cimel sunphotometer almucantar sky radiances and from aircraft in-situ observations during flight profiles at key sites.

  9. Boundary Layer Transition Flight Experiment Overview and In-Situ Measurements

    NASA Technical Reports Server (NTRS)

    Berger, Karen T.; Anderson, Brian P.; Campbell, Charles H.; Garske, Michael T.; Saucedo, Luis A.; Kinder, Gerald R.

    2010-01-01

    In support of the Boundary Layer Transition Flight Experiment (BLT FE) Project, a manufactured protuberance tile was installed on the port wing of Space Shuttle Orbiter Discovery for the flights of STS-119, STS-128 and STS-131. Additional instrumentation was installed in order to obtain more spatially resolved measurements downstream of the protuberance. This paper provides an overview of the BLT FE Project. Significant efforts were made to place the protuberance at an appropriate location on the Orbiter and to design the protuberance to withstand the expected environments. A high-level overview of the in-situ flight data is presented, along with a summary of the comparisons between pre- and post-flight analysis predictions and flight data. Comparisons show that predictions for boundary layer transition onset time closely match the flight data, while predicted temperatures were significantly higher than observed flight temperatures.

  10. In situ electrical conductivity measurements of H2O under static pressure up to 28 GPa

    NASA Astrophysics Data System (ADS)

    Liu, Bao; Gao, Yang; Han, Yonghao; Ma, Yanzhang; Gao, Chunxiao

    2016-08-01

    The in situ electrical conductivity measurements on water in both solid state and liquid state were performed under pressure up to 28 GPa and temperature from 77 K to 300 K using a microcircuit fabricated on a diamond anvil cell (DAC). Water chemically ionization mainly contributes to electrical conduction in liquid state, which is in accord with the results obtained under dynamic pressure. Energy band theory of liquid water was used to understand effect of static pressure on electrical conduction of water. The electric conductivity of H2O decreased discontinuously by four orders of magnitude at 0.7-0.96 GPa, indicating water frozen at this P-T condition. Correspondingly, the conduction of H2O in solid state is determined by arrangement and bending of H-bond in ice VI and ice VII. Based on Jaccard theory, we have concluded that the charge carriers of ice are already existing ions and Bjerrum defects.

  11. In situ technique for measuring the orthogonality of a plane wave to a substrate.

    PubMed

    Châteauneuf, Marc; Ayliffe, Michael H; Kirk, Andrew G

    2003-05-01

    A new compact in situ method of measuring the perpendicularity of a plane wave to a substrate is proposed. Off-axis cylindrical Fresnel lenses are used to focus a portion of the incident plane wave onto target lines. The displacement of the focal line from the targets is determined by the degree of angular misalignment. The proposed design has been incorporated into a 10-mm-thick fused-silica module, which enables us to obtain an alignment precision of better than 0.0083 degrees. This method is designed for use in optical assembly procedures that require an incident collimated beam that is normal to the alignment features. Experimental results are presented.

  12. In situ Magnetotransport Measurements in Ultrathin Bi Films: Evidence for Surface-Bulk Coherent Transport

    NASA Astrophysics Data System (ADS)

    Aitani, Masaki; Hirahara, Toru; Ichinokura, Satoru; Hanaduka, Masahiro; Shin, Dongyoon; Hasegawa, Shuji

    2014-11-01

    We performed in situ magnetotransport measurements on ultrathin Bi(111) films [4-30 bilayers (BLs), 16-120 Å thick] to elucidate the role of bulk or surface states in the transport phenomena. We found that the temperature dependence of the film conductivity shows no thickness dependence for the 6-16 BL films and is affected by the electron-electron scattering, suggesting surface-state dominant contribution. In contrast, the weak antilocalization effect observed by applying a magnetic field shows clear thickness dependence, indicating bulk transport. This apparent inconsistency is explained by a coherent bulk-surface coupling that produces a single channel transport. For the films thicker than 20 BLs, the behavior changes drastically which can likely be interpreted as a bulk dominant conduction.

  13. Measurement of in situ rates of selenate removal by dissimulatory bacterial reduction in sediments

    USGS Publications Warehouse

    Oremland, R.S.; Steinberg, N.A.; Maest, A.S.; Miller, L.G.; Hollibaugh, J.T.

    1990-01-01

    A radioisotope method for measurement of bacteria respiratory reduction of selenate to elemental selenium in aquatic sediments was devised. Sediments were labeled with [75Se]selenate, incubated, and washed, and 75Se0(s) was determined as counts remaining in the sediments. Core profiles of selenate reduction, sulfate reduction, and denitrification were made simultaneously in the sediments of an agricultural wastewater evaporation pond. Most of the in situ selenate reduction (85%) and all the denitrificatation activities were confined to the upper 4-8 cm of the profile, whereas sulfate reduction was greatest below 8 cm (89% of total). The integrated areal rate of selenate reduction was 301 ??mol m-2 day-1, which results in a turnover of water column selenate in 82.4 days.

  14. An in situ antimicrobial susceptibility testing method based on in vivo measurements of chlorophyll α fluorescence.

    PubMed

    Heliopoulos, Nikolaos S; Galeou, Angeliki; Papageorgiou, Sergios K; Favvas, Evangelos P; Katsaros, Fotios K; Stamatakis, Kostas

    2015-05-01

    Up to now antimicrobial susceptibility testing (AST) methods are indirect and generally involve the manual counting of bacterial colonies following the extraction of microorganisms from the surface under study and their inoculation in a separate procedure. In this work, an in situ, direct and instrumental method for the evaluation and assessment of antibacterial properties of materials and surfaces is proposed. Instead of indirectly determining antibacterial activity using the typical gram(-) test organisms with the subsequent manual colony count or inhibition zone measurement, the proposed procedure, employs photosynthetic gram(-) cyanobacteria deposited directly onto the surface under study and assesses cell proliferation and viability by a quick, accurate and reproducible instrumental chlorophyll fluorescence spectrophotometric technique. In contrast with existing methods of determination of antibacterial properties, it produces high resolution and quantitative results and is so versatile that it could be used to evaluate the antibacterial properties of any compound (organic, inorganic, natural or man-made) under any experimental conditions, depending on the targeted application.

  15. In situ x-ray diffraction measurements of the capillary fountain jet produced via ultrasonic atomization

    NASA Astrophysics Data System (ADS)

    Yano, Yohko F.; Douguchi, Junya; Kumagai, Atsushi; Iijima, Takao; Tomida, Yukinobu; Miyamoto, Toshiaki; Matsuura, Kazuo

    2006-11-01

    In situ x-ray diffraction measurements were carried out for investigating the liquid structure in the ultrasonic fountain jet to consider the mechanism of the "ultrasonic ethanol separation" reported by Sato et al. [J. Chem. Phys. 114, 2382 (2001)]. For pure liquids (water and ethanol), it was found that the high frequency ultrasound does not affect the liquid structure microscopically. For the 20mol% ethanol-water mixture, the estimated ethanol mole fraction in the ultrasonic fountain jet by using the position of the main maximum in the x-ray diffraction profile coincided with that in the reservoir. This result suggests that the ethanol separation is not caused by any distorted liquid structure under the ultrasound irradiation and occurs when or after the generation of the liquid droplet mist.

  16. In situ x-ray diffraction measurements of the capillary fountain jet produced via ultrasonic atomization.

    PubMed

    Yano, Yohko F; Douguchi, Junya; Kumagai, Atsushi; Iijima, Takao; Tomida, Yukinobu; Miyamoto, Toshiaki; Matsuura, Kazuo

    2006-11-07

    In situ x-ray diffraction measurements were carried out for investigating the liquid structure in the ultrasonic fountain jet to consider the mechanism of the "ultrasonic ethanol separation" reported by Sato et al. [J. Chem. Phys. 114, 2382 (2001)]. For pure liquids (water and ethanol), it was found that the high frequency ultrasound does not affect the liquid structure microscopically. For the 20 mol % ethanol-water mixture, the estimated ethanol mole fraction in the ultrasonic fountain jet by using the position of the main maximum in the x-ray diffraction profile coincided with that in the reservoir. This result suggests that the ethanol separation is not caused by any distorted liquid structure under the ultrasound irradiation and occurs when or after the generation of the liquid droplet mist.

  17. In situ observation and measurement of composites subjected to extremely high temperature

    NASA Astrophysics Data System (ADS)

    Fang, Xufei; Yu, Helong; Zhang, Guobing; Su, Hengqiang; Tang, Hongxiang; Feng, Xue

    2014-03-01

    In this work, we develop an instrument to study the ablation and oxidation process of materials such as C/SiC (carbon fiber reinforced silicon carbide composites) and ultra-high temperature ceramic in extremely high temperature environment. The instrument is integrated with high speed cameras with filtering lens, infrared thermometers and water vapor generator for image capture, temperature measurement, and humid atmosphere, respectively. The ablation process and thermal shock as well as the temperature on both sides of the specimen can be in situ monitored. The results show clearly the dynamic ablation and liquid oxide flowing. In addition, we develop an algorithm for the post-processing of the captured images to obtain the deformation of the specimens, in order to better understand the behavior of the specimen subjected to high temperature.

  18. IN SITU INFRARED MEASUREMENTS OF FREE-FLYING SILICATE DURING CONDENSATION IN THE LABORATORY

    SciTech Connect

    Ishizuka, Shinnosuke; Kimura, Yuki; Sakon, Itsuki

    2015-04-20

    We developed a new experimental system for infrared (IR) measurements on free-flying nucleating nanoparticles in situ and applied it to studies on silicate particles. We monitored the condensation of magnesium-bearing silicate nanoparticles from thermally evaporated magnesium and silicon monoxide vapor under an atmosphere of oxygen and argon. The IR spectrum of newly condensed particles showed a spectral feature for non-crystalline magnesium-bearing silicate that is remarkably consistent with the IR spectrum of astronomically observed non-crystalline silicate around oxygen-rich evolved stars. The silicate crystallized at <500 K and eventually developed a high crystallinity. Because of the size effects of nanoparticles, the silicate would be expected to be like a liquid at least during the initial stages of nucleation and growth. Our experimental results therefore suggest decreasing the possible formation temperature of crystalline silicates in dust formation environments with relatively higher pressure.

  19. In-Situ Measurements of the Radiation Stability of Amino Acids at 15-140 K

    NASA Technical Reports Server (NTRS)

    Gerakines, Perry A.; Hudson, Reggie L.; Moore, Marla H.; Bell, Jan-Luca

    2012-01-01

    We present new kinetics data on the radiolytic destruction of amino acids measured in situ with infrared spectroscopy. Samples were irradiated at 15, 100, and 140 K with D.8-MeV protons, and amino-acid decay was followed at each temperature with and without H2O present. Observed radiation products included CO2 and amines, consistent with amino-acid decarboxylation. The half-lives of glycine, alanine, and phenylalanine were estimated for various extraterrestrial environments. Infrared spectral changes demonstrated the conversion from the non-zwitterion structure NH2-CH2(R)-COOH at 15 K to the zwitterion structure +NH3-CH2(R)-COO- at 140 K for each amino acid studied.

  20. Airborne Aerosol In situ Measurements during TCAP: A Closure Study of Total Scattering

    SciTech Connect

    Kassianov, Evgueni I.; Berg, Larry K.; Pekour, Mikhail S.; Flynn, Connor J.; Tomlinson, Jason M.; Chand, Duli; Shilling, John E.; Ovchinnikov, Mikhail; Barnard, James C.; Sedlacek, Art; Schmid, Beat

    2015-07-31

    We present here a framework for calculating the total scattering of both non-absorbing and absorbing aerosol at ambient conditions from aircraft data. The synergistically employed aircraft data involve aerosol microphysical, chemical, and optical components and ambient relative humidity measurements. Our framework is developed emphasizing the explicit use of the complementary chemical composition data for estimating the complex refractive index (RI) of particles, and thus obtaining improved ambient size spectra derived from Optical Particle Counter (OPC) measurements. The feasibility of our framework for improved calculations of total aerosol scattering is demonstrated for different ambient conditions with a wide range of relative humidities (from 5 to 80%) using three types of data collected by the U.S. Department of Energy (DOE) G-1 aircraft during the recent Two-Column Aerosol Project (TCAP). Namely, these three types of data employed are: (1) size distributions measured by an Ultra High Sensitivity Aerosol Spectrometer (UHSAS; 0.06-1 µm), a Passive Cavity Aerosol Spectrometer (PCASP; 0.1-3 µm) and a Cloud and Aerosol Spectrometer (CAS; 0.6- >10 µm), (2) chemical composition data measured by an Aerosol Mass Spectrometer (AMS; 0.06-0.6 µm) and a Single Particle Soot Photometer (SP2; 0.06-0.6 µm), and (3) the dry total scattering coefficient measured by a TSI integrating nephelometer at three wavelengths (0.45, 0.55, 0.7 µm) and scattering enhancement factor measured with a humidification system at three RHs (near 45%, 65% and 90%) at a single wavelength (0.525 µm). We demonstrate that good agreement (~10% on average) between the observed and calculated scattering at these three wavelengths can be obtained using the best available chemical composition data for the RI-based correction of the OPC-derived size spectra. We also demonstrate that ignoring the RI-based correction and using non-representative RI values can cause a substantial underestimation (~40

  1. Measurement of the frequency stability of responders in aircraft

    NASA Technical Reports Server (NTRS)

    Liu, Xiaofan

    1994-01-01

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

  2. Reactor for in situ measurements of spatially resolved kinetic data in heterogeneous catalysis.

    PubMed

    Horn, R; Korup, O; Geske, M; Zavyalova, U; Oprea, I; Schlögl, R

    2010-06-01

    The present work describes a reactor that allows in situ measurements of spatially resolved kinetic data in heterogeneous catalysis. The reactor design allows measurements up to temperatures of 1300 degrees C and 45 bar pressure, i.e., conditions of industrial relevance. The reactor involves reactants flowing through a solid catalyst bed containing a sampling capillary with a side sampling orifice through which a small fraction of the reacting fluid (gas or liquid) is transferred into an analytical device (e.g., mass spectrometer, gas chromatograph, high pressure liquid chromatograph) for quantitative analysis. The sampling capillary can be moved with microm resolution in or against flow direction to measure species profiles through the catalyst bed. Rotation of the sampling capillary allows averaging over several scan lines. The position of the sampling orifice is such that the capillary channel through the catalyst bed remains always occupied by the capillary preventing flow disturbance and fluid bypassing. The second function of the sampling capillary is to provide a well which can accommodate temperature probes such as a thermocouple or a pyrometer fiber. If a thermocouple is inserted in the sampling capillary and aligned with the sampling orifice fluid temperature profiles can be measured. A pyrometer fiber can be used to measure the temperature profile of the solid catalyst bed. Spatial profile measurements are demonstrated for methane oxidation on Pt and methane oxidative coupling on Li/MgO, both catalysts supported on reticulated alpha-Al(2)O(3) foam supports.

  3. Reactor for in situ measurements of spatially resolved kinetic data in heterogeneous catalysis

    NASA Astrophysics Data System (ADS)

    Horn, R.; Korup, O.; Geske, M.; Zavyalova, U.; Oprea, I.; Schlögl, R.

    2010-06-01

    The present work describes a reactor that allows in situ measurements of spatially resolved kinetic data in heterogeneous catalysis. The reactor design allows measurements up to temperatures of 1300 °C and 45 bar pressure, i.e., conditions of industrial relevance. The reactor involves reactants flowing through a solid catalyst bed containing a sampling capillary with a side sampling orifice through which a small fraction of the reacting fluid (gas or liquid) is transferred into an analytical device (e.g., mass spectrometer, gas chromatograph, high pressure liquid chromatograph) for quantitative analysis. The sampling capillary can be moved with μm resolution in or against flow direction to measure species profiles through the catalyst bed. Rotation of the sampling capillary allows averaging over several scan lines. The position of the sampling orifice is such that the capillary channel through the catalyst bed remains always occupied by the capillary preventing flow disturbance and fluid bypassing. The second function of the sampling capillary is to provide a well which can accommodate temperature probes such as a thermocouple or a pyrometer fiber. If a thermocouple is inserted in the sampling capillary and aligned with the sampling orifice fluid temperature profiles can be measured. A pyrometer fiber can be used to measure the temperature profile of the solid catalyst bed. Spatial profile measurements are demonstrated for methane oxidation on Pt and methane oxidative coupling on Li/MgO, both catalysts supported on reticulated α -Al2O3 foam supports.

  4. Comparison of different methods for the in situ measurement of forest litter moisture content

    NASA Astrophysics Data System (ADS)

    Schunk, C.; Ruth, B.; Leuchner, M.; Wastl, C.; Menzel, A.

    2015-06-01

    Dead fine fuel (e.g. litter) moisture content is an important parameter for both forest fire and ecological applications as it is related to ignitability, fire behavior as well as soil respiration. However, the comprehensive literature review in this paper shows that there is no easy-to-use method for automated measurements available. This study investigates the applicability of four different sensor types (permittivity and electrical resistance measuring principles) for this measurement. Comparisons were made to manual gravimetric reference measurements carried out almost daily for one fire season and overall agreement was good (highly significant correlations with 0.792 ≦ r ≦ 0.947). Standard deviations within sensor types were linearly correlated to daily sensor mean values; however, above a certain threshold they became irregular, which may be linked to exceedance of the working ranges. Thus, measurements with irregular standard deviations were considered unusable and calibrations of all individual sensors were compared for useable periods. A large drift in the sensor raw value-litter moisture-relationship became obvious from drought to drought period. This drift may be related to installation effects or settling and decomposition of the litter layer throughout the fire season. Because of the drift and the in situ calibration necessary, it cannot be recommended to use the methods presented here for monitoring purposes. However, they may be interesting for scientific studies when some manual fuel moisture measurements are made anyway. Additionally, a number of potential methodological improvements are suggested.

  5. Direct measurement of speed of sound in cartilage in situ using ultrasound and magnetic resonance images.

    PubMed

    Nitta, N; Aoki, T; Hyodo, K; Misawa, M; Homma, K

    2013-01-01

    This study verified the accuracy of the speed of sound (SOS) measured by the combination method, which calculates the ratio between the thickness values of cartilage measured by using the magnetic resonance imaging (MRI) and the ultrasonic pulse-echo imaging, and investigated in vivo application of this method. SOS specific to an ultrasound imaging device was used as a reference value to calculate the actual SOS from the ratio of cartilage thicknesses obtained from MR and ultrasound images. The accuracy of the thickness measurement was verified by comparing results obtained using MRI and a non-contact laser, and the accuracy of the calculated SOS was confirmed by comparing results of the pulse-echo and transmission methods in vitro. The difference between laser and MRI measurements was 0.05 ± 0.22 mm. SOS values in a human knee measured by the combination method in the medial and lateral femoral condyles were 1650 ± 79 and 1642 ± 78 m/s, respectively (p < 0.05). The results revealed the feasibility of in situ SOS measurement using the combination method.

  6. In situ measurement of tissue impedance using an inductive coupling interface circuit.

    PubMed

    Chiu, Hung-Wei; Chuang, Jia-min; Lu, Chien-Chi; Lin, Wei-Tso; Lin, Chii-Wann; Lin, Mu-Lien

    2013-06-01

    In this work, a method of an inductive coupling impedance measurement (ICIM) is proposed for measuring the nerve impedance of a dorsal root ganglion (DRG) under PRF stimulation. ICIM provides a contactless interface for measuring the reflected impedance by an impedance analyzer with a low excitation voltage of 7 mV. The paper develops a calibration procedure involving a 50-Ω reference resistor to calibrate the reflected resistance for measuring resistance of the nerve in the test. A de-embedding technique to build the equivalent transformer circuit model for the ICIM circuit is also presented. A batteryless PRF stimulator with ICIM circuit demonstrated good accuracy for the acute measurement of DRG impedance both in situ and in vivo. Besides, an in vivo animal experiment was conducted to show that the effectiveness of pulsed radiofrequency (PRF) stimulation in relieving pain gradually declined as the impedance of the stimulated nerve increased. The experiment also revealed that the excitation voltage for measuring impedance below 25 mV can prevent the excitation of a nonlinear response of DRG.

  7. A microchip integrating cell array positioning with in situ single-cell impedance measurement.

    PubMed

    Guo, Xiaoliang; Zhu, Rong; Zong, Xianli

    2015-10-07

    This paper presents a novel microarray chip integrating cell positioning with in situ, real-time and long-time impedance measurement on a single cell. The microchip integrates a plurality of quadrupole-electrode units (termed positioning electrodes) patterned into an array with pairs of planar electrodes (termed measuring electrodes) located at the centers of each quadrupole-electrode unit. The positioning electrodes are utilized to trap and position living cells onto the measuring electrodes based on negative dielectrophoresis (nDEP), while the measuring electrodes are used to measure impedances of the trapped single cells. Each measuring electrode has a small footprint area of 7 × 7 μm(2) to ensure inhabiting only one single cell on it. However, the electrode with a small surface area has a low double-layer capacitance when it is immersed in a liquid solution, thus generating a large double-layer impedance, which reduces the sensitivity for impedance measurement on the single cell. To enlarge the effective surface areas of the measuring electrodes, a novel surface-modification process is proposed to controllably construct gold nanostructures on the surfaces of the measuring electrodes while the positioning electrodes are unstained. The double layer capacitances of the modified electrodes are increased by about one order after surface-modification. The developed microchip is used to monitor the adhering behavior of a single HeLa cell by measuring its impedance spectra in real time. The measured impedance is analyzed and used to extract cellular electrical parameters, which demonstrated that the cell compresses the electrical double layer in the process of adherence and adheres onto the measuring electrodes after 4-5 hours.

  8. DeepPIV: Measuring in situ Biological-Fluid Interactions from the Surface to Benthos

    NASA Astrophysics Data System (ADS)

    Katija, K.; Sherman, A.; Graves, D.; Kecy, C. D.; Klimov, D.; Robison, B. H.

    2015-12-01

    The midwater region of the ocean (below the euphotic zone and above the benthos) is one of the largest ecosystems on our planet, yet it remains one of the least explored. Little known marine organisms that inhabit midwater have developed strategies for swimming and feeding that ultimately contributes to their evolutionary success, and may inspire engineering solutions for societally relevant challenges. Fluid mechanics governs the interactions that midwater organisms have with their physical environment, but limited access to midwater depths and lack of non-invasive methods to measure in situ small-scale fluid motions prevent these interactions from being better understood. Significant advances in underwater vehicle technologies have only recently improved access to midwater. Unfortunately, in situ small-scale fluid mechanics measurement methods are still lacking in the oceanographic community. Here we present DeepPIV, an instrumentation package that can be affixed to remotely operated underwater vehicles that quantifies small-scale fluid motions from the surface of the ocean down to 4000 m depths. Utilizing ambient, suspended particulate in the coastal regions of Monterey Bay, fluid-structure interactions are evaluated on a range of marine organisms in midwater. Initial science targets include larvaceans, biological equivalents of flapping flexible foils, that create mucus houses to filter food. Little is known about the structure of these mucus houses and the function they play in selectively filtering particles, and these dynamics can serve as particle-mucus models for human health. Using DeepPIV, we reveal the complex structures and flows generated within larvacean mucus houses, and elucidate how these structures function.

  9. In Situ Light-Scattering Measurements of Morphologically Evolving Flame-Synthesized Oxide Nanoaggregates

    NASA Astrophysics Data System (ADS)

    Xing, Yangchuan; Koylu, Umit O.; Rosner, Daniel E.

    1999-04-01

    Nonspherical Al 2 O 3 aggregates produced in a laminar counterflow nonpremixed methane flame were investigated with an in situ laser light-scattering (LLS) technique in combination with a thermophoretic sampling transmission electron microscope (TS TEM) method. These flame-synthesized nanoparticles clearly underwent morphological changes following their formation (from precursor trimethylaluminum hydrolysis), mainly as a result of aggregation and sintering processes in the 3.3 10 4 K s heating environment. To characterize this particulate morphological evolution conveniently we made multiangular absolute LLS measurements and interpreted them based on the Rayleigh Debye Gans scattering theory for fractal aggregates. Optically determined fractal dimension D f , mean radius of gyration, aggregate size distribution, and local particle volume fraction p were found to be consistent with our independent ex situ TS TEM experiments. D f (optically inferred) increased from 1.60 to 1.84 with axial position, confirming the morphological evolution of alumina aggregates owing to finite-rate, spatially resolved high-temperature sintering. An extension of our TS TEM method was successfully applied, for the first time to our knowledge, to inorganic particles. p inferred by means of this ex situ technique generally agreed with that from the in situ LLS technique, supporting our interpretation of both measurements. Moreover, an optically inferred net sintering rate of alumina aggregates approaching the flame was estimated to be consistent with the available TEM data. The LLS methods and results presented here are expected to permit more comprehensive mechanistic analyses of nanoaggregate sintering and coagulation kinetics in such flame environments, ultimately improving the modeling of more-complex (e.g., turbulent, high-pressure) combustion systems involving nanoparticle formation and evolution.

  10. An in-situ electropolymerization based sensor for measuring salt content in crude oil.

    PubMed

    Aleisa, Rashed M; Akmal, Naim

    2015-01-01

    Determining salt content is a vital procedure in the petroleum industry during the process of crude oil transportation, refining and production. Monitoring the salinity value using a fast and direct technique can substantially lower the cost of crude oil in its processing and its production stages. In the present work, a novel analytical method was developed to detect the amount of salt present in crude oil in a quick and reliable manner. The measurement is based on the rate of in-situ electropolymerization of a monomer such as aniline in association with the salt content in the crude oil. The salt dispersed in the hydrocarbon matrix is used as an electrolyte in the electrolytic system to induce an electropolymerization reaction upon the induction of voltages, in which the salt content is measured corresponding to the polymeric film formation on the working electrode surface. Acetonitrile and N-methylpyrrolidone (NMP) were used in the electrochemical cell as solvents, and cyclic voltammetry tests were performed for Arabian crude oil solutions in the presence of aniline. The method has shown an excellent detection response for very low concentrations of salt. Four Arabian crude oils with salt concentrations of 34.2, 28.5, 14.3 and 5.71 mg L(-1) have produced current intensity of 180.1, 172.6, 148.1 and 134.2 µA at an applied current potential of 1.75 V (vs. Ag/AgCl), respectively. A Calibration curve was obtained in the range of 5-35 mg L(-1), giving limits of detection and quantitation at 1.98 and 5.95 mg L(-1), respectively. The in-situ electropolymerization based sensor has significant advantages over the existing techniques of salt monitoring in crude oil such as fast response, temperature independency, electrode stability, and minimum sample preparation.

  11. Comparison of Water Potentials Measured by In Situ Psychrometry and Pressure Chamber in Morphologically Different Species 1

    PubMed Central

    Turner, Neil C.; Spurway, R. A.; Schulze, E.-D.

    1984-01-01

    Leaf water potentials measured by in situ psychrometry were compared with leaf water potentials measured by the pressure chamber technique at various values of water potential in Helianthus annuus, Helianthus nuttallii, Vigna unguiculata, Nerium oleander, Pistacia vera, and Corylus avellana. In V. unguiculata, the leaf water potentials measured by the in situ psychrometer oscillated at the same periodicity as, and proportional to, the leaf conductance. In all species, potentials measured by in situ psychrometers operating in the psychrometric mode were linearly correlated with potentials measured with the pressure chamber. However, the in situ psychrometers underestimated the leaf water potential in the two Helianthus species at low water potentials and overestimated the water potential in P. vera, N. oleander, and C. avellana. The underestimation in the two Helianthus species at low water potentials resulted from differences in water potential across the leaf. The overestimation in P. vera, N. oleander, and C. avellana was considered to arise from low epidermal conductances in these species even after abrasion of the cuticle. Pressure-volume studies with Lycopersicon esculentum showed that less water was expressed from distal than proximal leaflets when the whole leaf was slowly pressurized. The implication of this for water relations characteristics obtained by pressure-volume techniques is discussed. We conclude that in situ psychrometers are suitable for following dynamic changes in leaf water potential, but should be used with caution on leaves with low epidermal conductances. PMID:16663415

  12. Developing a Model-Based Framework for Quality Assessments of In-Situ Measurement Protocols for Albedo

    NASA Astrophysics Data System (ADS)

    Adams, Jennifer Susan; Gobron, Nadine; Widlowski, Jean-Luc; Mio, Corrado

    2016-08-01

    Validation of satellite-based retrievals of land surface albedo using in-situ measurements is essential to identify differences between them, to improve retrieval algorithms and to assess conformity to accuracy requirements. Differences between in-situ and satellite-based retrievals depend on the actual difference and their associated uncertainties, where it is crucial that the uncertainties of both can be computed to properly understand potential differences. This study introduces a model-based framework for assessing the quality of in-situ albedo measurements. A 3D Monte Carlo Ray Tracing (MCRT) radiative transfer model is used to simulate field measurements of surface albedo, and is able to identify and quantify potential sources of error in the field measurement. Compliance with the World Meteorological Organisation (WMO) requirement for 3% accuracy is tested.

  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. Development of a New Type Sensor for In-Situ Space Debris Measurement

    NASA Astrophysics Data System (ADS)

    Kitazawa, Y.; Sakurai, A.; Yasaka, T.; Kunihiro, F.; Hanada, T.; Hasegawa, S.; Matsumotom H.

    Space debris environment models are used for debris impact risk assessments for spacecraft. The comparison of representative models revealed that there is large difference in the flux value of the size range from a hundred micrometers to several millimeters. The uncertainty of models is caused by the lack of measurement data. Although the large size objects (larger than several cm) can be detected by grand based observations, and small size debris (smaller than hundred micrometers) is measured by spacecraft surface inspections, the size range of hundred micrometers to several millimeters cannot be detected by ground observations and cannot get enough data from spacecraft surface inspections. On the other hand, importance of measurement of these large particles has been increased especially in the engineering viewpoints (e.g. space system design and operations). The in-situ measurement data are useful for; 1) verifications of space debris environment models, 2) verifications of space debris environment evolution models, 3) real time detection and evaluation of the influences on space environment by unexpected events, such as explosions on an orbit (ex. ASAT ( Anti-Satellite Test) and satellites collisions). Authors have been developing the in-situ measurement sensor to detect dust particles ranging from a hundred micrometers to several millimeters. Since spatial density of this size range of debris is low, the sensor must have a large detection area, while the sensor is required to be low in mass, low in power, robust, and low in telemetry requirements. The sensor consists of multitudes of thin and conductive strips which are formed with fine pitch on a thin film of nonconductive material. A dust particle impact is detected when one or more strips are severed by the impact hole. It is simple to produce and use and requires almost no calibration as it is essentially a digital system. Features of the sensor are; 1) Simple mechanism, 2) High reliability (sensing

  15. Spatio-Temporal Variability of Atmospheric CO2 as Observed from In-Situ Measurements over North America during NASA Field Campaigns (2004-2008)

    NASA Technical Reports Server (NTRS)

    Choi, Yonghoon; Vay, Stephanie A.; Woo, Jung-Hun; Choi, Kichul; Diskin, Glenn S.; Sachse, G. W.; Vadrevu, Krishna P.; Czech, E.

    2009-01-01

    Regional-scale measurements were made over the eastern United States (Intercontinental Chemical Transport Experiment - North America (INTEX-NA), summer 2004); Mexico (Megacity Initiative: Local and Global Research Observations (MILAGRO), March 2006); the eastern North Pacific and Alaska (INTEX-B May 2006); and the Canadian Arctic (Arctic Research of the Composition of the Troposphere from Aircraft and Satellites (ARCTAS), spring and summer 2008). For these field campaigns, instrumentation for the in situ measurement of CO2 was integrated on the NASA DC-8 research aircraft providing high-resolution (1 second) data traceable to the WMO CO2 mole fraction scale. These observations provide unique and definitive data sets via their intermediate-scale coverage and frequent vertical profiles (0.1 - 12 km) for examining the variability CO2 exhibits above the Earth s surface. A bottom-up anthropogenic CO2 emissions inventory (1deg 1deg) and processing methodology has also been developed for North America in support of these airborne science missions. In this presentation, the spatio-temporal distributions of CO2 and CO column values derived from the campaign measurements will be examined in conjunction with the emissions inventory and transport histories to aid in the interpretation of the CO2 observations.

  16. 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.

  17. Evaluation of a portable FTIR for in-situ field measurements of surface reflectance

    NASA Astrophysics Data System (ADS)

    Newsom, Rob K.; Kaiser, Robert D.; Schutte, August O.

    2004-08-01

    Development of target detection algorithms and simulation models for present and future multispectral and hyperspectral sensor systems requires accurate characterization of the reflectance and thermal emission of natural and man-made materials. Fourier transform spectrometry is one method for obtaining relatively high spectral resolution, in-situ measurements of surface reflectance. This paper discusses the performance characteristics of the SOC-400T FTIR and its application to field measurements. The SOC-400T is a relatively small and portable FTIR reflectometer that was designed to measure the directional reflectance and calculate the directional thermal emittance of surfaces in the spectral range from 2 to 25 ημm. The SOC-400T uses a silicone carbide glowbar to illuminate samples. This permits accurate results to be obtained in the MWIR. We recently deployed this instrument to the field to perform measurements on various materials of interest to the military. Prior to the deployment, the instrument was evaluated to assess its performance under true field operating conditions. This paper specifically examines noise characteristics, warmup time, transients induced by reorientation of the sensor, spurious detector artifacts, and sensitivity to vibration. We also address the practical issue associated with positioning, stabilizing, and calibrating the instrument for field measurements of irregular or arbitrarily oriented surfaces.

  18. In Situ Measurements of Spectral Emissivity of Materials for Very High Temperature Reactors

    SciTech Connect

    G. Cao; S. J. Weber; S. O. Martin; T. L. Malaney; S. R. Slattery; M. H. Anderson; K. Sridharan; T. R. Allen

    2011-08-01

    An experimental facility for in situ measurements of high-temperature spectral emissivity of materials in environments of interest to the gas-cooled very high temperature reactor (VHTR) has been developed. The facility is capable of measuring emissivities of seven materials in a single experiment, thereby enhancing the accuracy in measurements due to even minor systemic variations in temperatures and environments. The system consists of a cylindrical silicon carbide (SiC) block with seven sample cavities and a deep blackbody cavity, a detailed optical system, and a Fourier transform infrared spectrometer. The reliability of the facility has been confirmed by comparing measured spectral emissivities of SiC, boron nitride, and alumina (Al2O3) at 600 C against those reported in literature. The spectral emissivities of two candidate alloys for VHTR, INCONEL{reg_sign} alloy 617 (INCONEL is a registered trademark of the Special Metals Corporation group of companies) and SA508 steel, in air environment at 700 C were measured.

  19. In situ measurement of low-Z material coating thickness on high Z substrate for tokamaks

    SciTech Connect

    Mueller, D. Roquemore, A. L.; Jaworski, M.; Skinner, C. H.; Miller, J.; Creely, A.; Raman, P.; Ruzic, D.

    2014-11-15

    Rutherford backscattering of energetic particles can be used to determine the thickness of a coating of a low-Z material over a heavier substrate. Simulations indicate that 5 MeV alpha particles from an {sup 241}Am source can be used to measure the thickness of a Li coating on Mo tiles between 0.5 and 15 μm thick. Using a 0.1 mCi source, a thickness measurement can be accomplished in 2 h of counting. This technique could be used to measure any thin, low-Z material coating (up to 1 mg/cm{sup 2} thick) on a high-Z substrate, such as Be on W, B on Mo, or Li on Mo. By inserting a source and detector on a moveable probe, this technique could be used to provide an in situ measurement of the thickness of Li coating on NSTX-U Mo tiles. A test stand with an alpha source and an annular solid-state detector was used to investigate the measurable range of low-Z material thicknesses on Mo tiles.

  20. In situ measurements of sediment acoustic properties in Currituck Sound and comparison to models.

    PubMed

    Lee, Kevin M; Ballard, Megan S; McNeese, Andrew R; Muir, Thomas G; Wilson, Preston S; Costley, R Daniel; Hathaway, Kent K

    2016-11-01

    In situ measurements of compressional and shear wave speed and attenuation were collected 30 cm below the water-sediment interface in Currituck Sound, North Carolina at two field locations having distinctly different sediment types: medium-to-fine-grained sand and fine-grained sand with approximately 10% mud content. Shear wave measurements were performed with bimorph transducers to generate and receive horizontally polarized shear waves in the 300 Hz to 1 kHz band, and compressional wave measurements were performed using hydrophones operated in the 5 kHz to 100 kHz band. Sediment samples were collected at both measurement sites and later analyzed in the laboratory to characterize the sediment grain size distribution for each field location. Compressional and shear wave speed and attenuation were estimated from the acoustic measurements, and preliminary comparisons to the extended Biot model by Chotiros and Isakson [J. Acoust. Soc. 135, 3264-3279 (2014)] and the viscous grain-shearing theory by Buckingham [J. Acoust. Soc. 136, 2478-2488 (2014)] were performed.

  1. Martian Chronology and Atmospheric Composition: In Situ Measurements versus Sample Return

    NASA Technical Reports Server (NTRS)

    Bogard, Donald D.

    2008-01-01

    I examine two significant issues of martian science from the point of view of in situ measurements by robotic spacecraft versus sample return and analysis in terrestrial labs. (1) To define martian history, ages of geological processes and surface features are required. Estimated ages from surface crater densities have limitations, and the ages measured for martian meteorites cannot be associated with specific martian locales. Whereas returned martian rocks could be accurately dated, some have suggested sending a robotic spacecraft to Mars to measure rock ages using the classical K- Ar-40 technique, considered the easiest to implement. (2) To understand the evolution of the martian atmosphere and its interactions with the surface, requires precise measurements of atmospheric composition. A significant amount of information has derived from measurements by Viking and of martian meteorites. Instrumentation on the Mars Science Lander (MSL) spacecraft to be launched in the near future promises to determine atmospheric composition even more precisely. If MSL is successful, which questions about atmospheric composition will remain and thus will require atmospheric sample return to answer?

  2. Direct strike lightning measurement system. [for aircraft

    NASA Technical Reports Server (NTRS)

    Thomas, M. E.

    1981-01-01

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

  3. Development of a pattern to measure multiscale deformation and strain distribution via in situ FE-SEM observations.

    PubMed

    Tanaka, Y; Naito, K; Kishimoto, S; Kagawa, Y

    2011-03-18

    We investigated a method for measuring deformation and strain distribution in a multiscale range from nanometers to millimeters via in situ FE-SEM observations. A multiscale pattern composed of a grid as well as random and nanocluster patterns was developed to measure the localized deformation at the specimen surface. Our in situ observations of a carbon fiber-reinforced polymer matrix composite with a hierarchical microstructure subjected to loading were conducted to identify local deformation behaviors at various boundaries. We measured and analyzed the multiscale deformation and strain localizations during various stages of loading.

  4. The Probing In-Situ With Neutron and Gamma Rays (PING) Instrument for Planetary Composition Measurements

    NASA Technical Reports Server (NTRS)

    Parsons, A.; Bodnarik, J.; Evans, L.; McClanahan, T.; Namkung, M.; Nowicki, S.; Schweitzer, J.; Starr, R.

    2012-01-01

    The Probing In situ with Neutrons and Gamma rays (PING) instrument (formerly named PNG-GRAND) [I] experiment is an innovative application of the active neutron-gamma ray technology successfully used in oil field well logging and mineral exploration on Earth over many decades. The objective of our active neutron-gamma ray technology program at NASA Goddard Space Flight Center (NASA/GSFC) is to bring PING to the point where it can be flown on a variety of surface lander or rover missions to the Moon, Mars, Venus, asteroids, comets and the satellites of the outer planets and measure their bulk surface and subsurface elemental composition without the need to drill into the surface. Gamma-Ray Spectrometers (GRS) have been incorporated into numerous orbital planetary science missions. While orbital measurements can map a planet, they have low spatial and elemental sensitivity due to the low surface gamma ray emission rates reSUlting from using cosmic rays as an excitation source, PING overcomes this limitation in situ by incorporating a powerful neutron excitation source that permits significantly higher elemental sensitivity elemental composition measurements. PING combines a 14 MeV deuterium-tritium Pulsed Neutron Generator (PNG) with a gamma ray spectrometer and two neutron detectors to produce a landed instrument that can determine the elemental composition of a planet down to 30 - 50 cm below the planet's surface, The penetrating nature of .5 - 10 MeV gamma rays and 14 MeV neutrons allows such sub-surface composition measurements to be made without the need to drill into or otherwise disturb the planetary surface, thus greatly simplifying the lander design, We are cun'ently testing a PING prototype at a unique outdoor neutron instrumentation test facility at NASA/GSFC that provides two large (1.8 m x 1.8 m x ,9 m) granite and basalt test formations placed outdoors in an empty field, Since an independent trace elemental analysis has been performed on both these

  5. A measurement system for aircraft/weapon electromagnetic compatibility

    SciTech Connect

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

    1991-01-01

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

  6. Benthic carbon mineralization in hadal trenches: Assessment by in situ O2 microprofile measurements

    NASA Astrophysics Data System (ADS)

    Wenzhöfer, F.; Oguri, K.; Middelboe, M.; Turnewitsch, R.; Toyofuku, T.; Kitazato, H.; Glud, R. N.

    2016-10-01

    Hadal trenches are considered to act as depo-centers for organic material at the trench axis and host unique and elevated biomasses of living organisms as compared to adjacent abyssal plains. To explore the diagenetic activity in hadal trench environments we quantified in situ benthic O2 consumption rates and sediment characteristics from the trench axis of two contrasting trench systems in the Pacific Ocean; the Izu-Bonin Trench underlying mesotrophic waters and the Tonga Trench underlying oligotrophic waters. In situ oxygen consumption at the Izu-Bonin Trench axis site (9200 m; 746±103 μmol m-2 d-1; n=27) was 3-times higher than at the Tonga Trench axis site (10800 m; 225±50 μmol m-2 d-1; n=7) presumably reflecting the higher surface water productivity in the Northern Pacific. Comparing benthic O2 consumption rates measured in the central hadal Tonga Trench to that of nearby (60 km distance) abyssal settings (6250 m; 92±44 μmol m-2 d-1; n=16) revealed a 2.5 higher activity at the trench bottom. Onboard investigations on recovered sediment furthermore revealed that the prokaryotic abundance and concentrations of phytopigments followed this overall trend (i.e minimum values at the abyssal site followed by higher values from the Tonga and Izu-Bonin Trenches axis, respectively). Excess 210Pb profiles suggested that mass-wasting events contributed to the deposition of material enhancing the concentration of organic matter in the central trench as compared to the abyssal settings. Our results complement recent findings from the Challenger deep in the Mariana Trench area, which also revealed elevated diagenetic activity in the central trench underpinning the importance of hadal ecosystems for the deep sea carbon cycling.

  7. Development of ``Smart Sediments'' to Conduct In-Situ Measurements within Mobile Bed Layers

    NASA Astrophysics Data System (ADS)

    Frank, D. P.; Foster, D.; Chou, P.

    2010-12-01

    Observing the motion of sediment beds in nearshore environments has been previously limited by technological capabilities. Experiments utilizing both optical and acoustic techniques have provided great insight into the hydrodynamics within the bottom boundary and mobile bed layers. However, most previous technologies were not capable of in-situ investigations of the morphodynamics within these layers because they are generally thin, within 1-100 grain diameters. In-situ measurements of the mobile bed layer will be made with new state-of-the-art micro-electronic machines (MEM’s). These mobile nodes are 13x11x7 mm and are equipped with tri-axial accelerometers, temperature and pressure sensors, in addition to, a wireless transmitter and micro-processor. In this generation, the ceramic enclosure is comparable in size to coarse gravel. The device has the same physical properties as quartz and should provide significant insight into incipient motion and sediment transport under oscillatory flow fields in the nearshore environment. The mobile nodes will first be tested at a field-scale laboratory wave facility before being used in the nearshore. The morphodynamics of heterogeneous sediments will also be explored. The overarching goal of this project is to enhance the scientific community’s understanding of the hydrodynamics and morphodynamics within the wave-dominated bottom boundary layer environment through technological development of the “smart sediments”. In particular, we seek to test the hypothesis that in unsteady flow where the sediment may be heterogeneous, the incipient motion of a sediment bed results from a combination of the shear stress gradient and pressure gradient. The goal of this presentation is to evaluate the sensors on their physical properties such as moment of inertia and radio frequency transmission.

  8. Integration of satellite data and in situ measurements to improve coastal water quality monitoring

    NASA Astrophysics Data System (ADS)

    Lacava, Teodosio

    2015-04-01

    Coastal areas are "sensitive" zones exposed to different natural hazards and anthropic risks. The increasing level of urbanization, the even more irrational exploitation of those areas and, more generally, climate changes are some of the most relevant phenomena able to strongly change such sites. For these reasons, it is necessary to implement an adequate water quality monitoring system able to give a reliable description of water status for reducing the negative effects which coastal marine waters are exposed to. Remote sensing data offer a relevant contribution in this framework, providing, with a quite good level of accuracy, information about the spatial distribution of sea water constituents over large areas with high temporal rates and at relatively low costs. On the other hand, in situ measurements allow to analyze the history of these elements at a very small scale, both in terms of investigated area and period. The integration of these two kind of information may improve the monitoring in the space-time domain of a specific area, allowing also for a calibration, at local scale, of the satellite data/products. In this paper results achieved in such a context while carrying out two projects on Mediterranean Sea water quality will be described. More than 15 years of MODIS Ocean Colour data have been analyzed and compared with different specific in-situ and airborne data concerning different areas of Mediterranean Sea collected in the framework of the following projects: IOSMOS (IOnian Sea water quality MOnitoring by Satellite data, OP ERDF Basilicata) and MOMEDAS (MOnitoraggio delle acque del mar MEditerraneo mediante DAti Satellitari, OP Basilicata ESF). Specifically, preliminary achievements regarding the analysis of Chlorophyll-a (Chl-a) and diffuse attenuation coefficient at 490 nm (Kd 490) products as well as suspended sediment material (SSM) transport phenomena and the Sea Surface Temperature (SST) variations occurring in the analyzed areas will be

  9. Bed shear stress estimation on an open intertidal flat using in situ measurements

    NASA Astrophysics Data System (ADS)

    Zhu, Q.; van Prooijen, B. C.; Wang, Z. B.; Ma, Y. X.; Yang, S. L.

    2016-12-01

    Accurate estimations for the bed shear stress are essential to predict the erosion and deposition processes in estuaries and coasts. This study used high-frequency in situ measurements of water depths and near-bed velocities to estimate bed shear stress on an open intertidal flat in the Yangtze Delta, China. To determine the current-induced bed shear stress (τc) the in situ near-bed velocities were first decomposed from the turbulent velocity into separate wave orbital velocities using two approaches: a moving average (MA) and energy spectrum analysis (ESA). τc was then calculated and evaluated using the log-profile (LP), turbulent kinetic energy (TKE), modified TKE (TKEw), Reynolds stress (RS), and inertial dissipation (ID) methods. Wave-induced bed shear stress (τw) was estimated using classic linear wave theory. The total bed shear stress (τcw) was determined based on the Grant-Madsen wave-current interaction model (WCI). The results demonstrate that when the ratio of significant wave height to water depth (Hs/h) is greater than 0.25, τcw is significantly overestimated because the vertical velocity fluctuations are contaminated by the surface waves generated by high winds. In addition, wind enhances the total bed shear stress as a result of the increases in both τw and τc generated by the greater wave height and reinforcing of vertical turbulence, respectively. From a comparison of these various methods, the TKEw method associated with ESA decomposition was found to be the best approach because: (1) this method generates the highest mean index of agreement; (2) it uses vertical velocities that are less affected by Doppler noise; and (3) it is less sensitive to the near-bed stratification structure and uncertainty in bed location and roughness.

  10. in situ Measures of LED Installations: Results of Air and Ground Surveys

    NASA Astrophysics Data System (ADS)

    Craine, Eric Richard; Craine, Brian L.

    2015-08-01

    Light Emitting Diode (LED) outdoor light fixtures of different types are rapidly proliferating in many communities, particularly in the form of continuous roadway, work, and parking lot lights. These lights offer a wide range of benefits, but many in the astronomical community have expressed various concerns about their impact on local observatory facilities. We have spent several years developing complementary ground-based and aerial techniques of measuring light installations in the field. Unfortunately, large community retrofits of lighting preclude comprehensive measurement of the changes that result unless baseline data have been collected prior to completion of the new installations. Because of the rapidity of conversion to LEDs, it is increasingly difficult to conduct informative before and after surveys. As a point of interest to astronomers, we offer examples of some in situ measurements of LED installations, compare those measurements to results for older light fixtures, and discuss some of the implications for astronomy. These objective data may be helpful in reaching an informed perspective on how LED lights perform in typical settings.

  11. Summary and analysis of 216 GHz polarimetric measurements of in-situ rain

    NASA Astrophysics Data System (ADS)

    Hedden, Abigail S.; Wikner, David A.; Bradley, Russell W.

    2015-05-01

    The Army Research Laboratory (ARL) has developed a polarimetric frequency-modulated continuous-wave (FMCW) instrumentation radar that has been used to study the polarization and backscatter properties of in-situ rain in the 220 GHz atmospheric window. A summary of the preliminary measurements is presented in this work including an analysis of the co-polarization backscatter and attenuation characteristics measured at 216 GHz. A marginal detection of the copolarization backscatter signature of rain was made during a series of fast-moving, heavy downpour thunderstorm events. A detection limit of -40±3 dB[m2/m3] was found for the VV-polarization cross section per unit volume for rain rates up to 150 mm/hr. Co-polarization (VV- and HH-polarization) attenuation characteristics measured at high rain rates (< 20 mm/hr) were well described by a Joss thunderstorm drop distribution in the high frequency limit, where drop size is much greater than the observation wavelength. Observations at 216 GHz suggest attenuation levels of 8-10 dB/km at rain rates above 20 mm/hr, strengthening previous evidence that attenuation through rain is independent of frequency under high rain rate conditions. Attenuation measurements at lower rain rates (< 20 mm/hr) were qualitatively consistent with both Laws and Parsons and Joss thunderstorm distributions.

  12. Comparison of Doppler scintillation and in situ spacecraft plasma measurements of interplanetary disturbances

    NASA Technical Reports Server (NTRS)

    Woo, Richard; Schwenn, Rainer

    1991-01-01

    Results are presented of detailed comparisons between Doppler scintillation and in situ plasma measurements to improve the understanding of Doppler scintillation transients. During a combined observing period of nearly 3 mo in 1981-1982 near solar maximum, 22 transients were observed by the Pioneer Venus Orbiter spacecraft and 23 shocks were observed by Helios 1. It is found that at least 84 percent of the transients are shocks, while at least 90 percent of the shocks are transients. Although the temporal profiles of Doppler scintillation and mass flux density are similar, the magnitudes of the Doppler scintillation transients may not simply reflect those of mass flux density. Only one pronounced solar wind event that was observed in the mass flux density measurements showed no signature in the scintillation data; field and particle measurements by Helios 1 suggest that it is a noncompressive density enhancement and/or a magnetic cloud. It is shown that Doppler scintillation measurements can now be used by themselves to detect and locate interplanetary shocks near the sun with a relatively high degree of certainty.

  13. Accurate in situ measurement of complex refractive index and particle size in intralipid emulsions.

    PubMed

    Dong, Miao L; Goyal, Kashika G; Worth, Bradley W; Makkar, Sorab S; Calhoun, William R; Bali, Lalit M; Bali, Samir

    2013-08-01

    A first accurate measurement of the complex refractive index in an intralipid emulsion is demonstrated, and thereby the average scatterer particle size using standard Mie scattering calculations is extracted. Our method is based on measurement and modeling of the reflectance of a divergent laser beam from the sample surface. In the absence of any definitive reference data for the complex refractive index or particle size in highly turbid intralipid emulsions, we base our claim of accuracy on the fact that our work offers several critically important advantages over previously reported attempts. First, our measurements are in situ in the sense that they do not require any sample dilution, thus eliminating dilution errors. Second, our theoretical model does not employ any fitting parameters other than the two quantities we seek to determine, i.e., the real and imaginary parts of the refractive index, thus eliminating ambiguities arising from multiple extraneous fitting parameters. Third, we fit the entire reflectance-versus-incident-angle data curve instead of focusing on only the critical angle region, which is just a small subset of the data. Finally, despite our use of highly scattering opaque samples, our experiment uniquely satisfies a key assumption behind the Mie scattering formalism, namely, no multiple scattering occurs. Further proof of our method's validity is given by the fact that our measured particle size finds good agreement with the value obtained by dynamic light scattering.

  14. Accurate in situ measurement of complex refractive index and particle size in intralipid emulsions

    NASA Astrophysics Data System (ADS)

    Dong, Miao L.; Goyal, Kashika G.; Worth, Bradley W.; Makkar, Sorab S.; Calhoun, William R.; Bali, Lalit M.; Bali, Samir

    2013-08-01

    A first accurate measurement of the complex refractive index in an intralipid emulsion is demonstrated, and thereby the average scatterer particle size using standard Mie scattering calculations is extracted. Our method is based on measurement and modeling of the reflectance of a divergent laser beam from the sample surface. In the absence of any definitive reference data for the complex refractive index or particle size in highly turbid intralipid emulsions, we base our claim of accuracy on the fact that our work offers several critically important advantages over previously reported attempts. First, our measurements are in situ in the sense that they do not require any sample dilution, thus eliminating dilution errors. Second, our theoretical model does not employ any fitting parameters other than the two quantities we seek to determine, i.e., the real and imaginary parts of the refractive index, thus eliminating ambiguities arising from multiple extraneous fitting parameters. Third, we fit the entire reflectance-versus-incident-angle data curve instead of focusing on only the critical angle region, which is just a small subset of the data. Finally, despite our use of highly scattering opaque samples, our experiment uniquely satisfies a key assumption behind the Mie scattering formalism, namely, no multiple scattering occurs. Further proof of our method's validity is given by the fact that our measured particle size finds good agreement with the value obtained by dynamic light scattering.

  15. In-situ roundness measurement and correction for pin journals in oscillating grinding machines

    NASA Astrophysics Data System (ADS)

    Yu, Hongxiang; Xu, Mengchen; Zhao, Jie

    2015-01-01

    In the mass production of vehicle-engine crankshafts, pin chasing grinding using oscillating grinding machines is a widely accepted method to achieve flexible and efficient performance. However, the eccentric movement of pin journals makes it difficult to develop an in-process roundness measurement scheme for the improvement of contour precision. Here, a new in-situ roundness measurement strategy is proposed with high scanning speed. The measuring mechanism is composed of a V-block and an adaptive telescopic support. The swing pattern of the telescopic support and the V-block is analysed for an equal angle-interval signal sampling. Hence roundness error signal is extracted in frequency domain using a small-signal model of the V-block roundness measurement method and the Fast Fourier Transformation. To implement the roundness data in the CNC coordinate system of an oscillating grinding machine, a transformation function is derived according to the motion model of pin chasing grinding methodology. Computer simulation reveals the relationship between the rotational position of the crankshaft component and the scanning angle of the displacement probe on the V-block, as well as the influence introduced by the rotation centre drift. Prototype investigation indicates the validity of the theoretical analysis and the feasibility of the new strategy.

  16. In situ measurement of fixed charge evolution at silicon surfaces during atomic layer deposition

    SciTech Connect

    Ju, Ling; Watt, Morgan R.; Strandwitz, Nicholas C.

    2015-02-09

    Interfacial fixed charge or interfacial dipoles are present at many semiconductor-dielectric interfaces and have important effects upon device behavior, yet the chemical origins of these electrostatic phenomena are not fully understood. We report the measurement of changes in Si channel conduction in situ during atomic layer deposition (ALD) of aluminum oxide using trimethylaluminum and water to probe changes in surface electrostatics. Current-voltage data were acquired continually before, during, and after the self-limiting chemical reactions that result in film growth. Our measurements indicated an increase in conductance on p-type samples with p{sup +} ohmic contacts and a decrease in conductance on analogous n-type samples. Further, p{sup +} contacted samples with n-type channels exhibited an increase in measured current and n{sup +} contacted p-type samples exhibited a decrease in current under applied voltage. Device physics simulations, where a fixed surface charge was parameterized on the channel surface, connect the surface charge to changes in current-voltage behavior. The simulations and analogous analytical relationships for near-surface conductance were used to explain the experimental results. Specifically, the changes in current-voltage behavior can be attributed to the formation of a fixed negative charge or the modification of a surface dipole upon chemisorption of trimethylaluminum. These measurements allow for the observation of fixed charge or dipole formation during ALD and provide further insight into the electrostatic behavior at semiconductor-dielectric interfaces during film nucleation.

  17. Monolayers of poly(amido amine) dendrimers on mica - In situ streaming potential measurements.

    PubMed

    Michna, Aneta; Adamczyk, Zbigniew; Sofińska, Kamila; Matusik, Katarzyna

    2017-01-01

    The deposition of poly(amido amine) dendrimers on mica at various pHs was studied by the atomic force microscopy (AFM) and in situ streaming potential measurements. Bulk characteristics of dendrimers were acquired by using the dynamic light scattering (DLS) and the laser Doppler velocimetry (LDV). The hydrodynamic radius derived from DLS measurements was 5.2nm for the ionic strength of 10(-2)M and pH range 4-10. The electrophoretic mobility, the zeta potential and the number of electrokinetic charges per molecule were derived as a function of pH from the LDV measurements. It was revealed that the dendrimers are positively charged for pH up to 10. This promoted their deposition on negatively charged mica substrate whose kinetics was quantitatively evaluated by direct AFM imaging and streaming potential measurements interpreted in terms of the electrokinetic model. The desorption kinetics of dendrimers under flowing conditions from monolayers of various coverage was also studied. It was revealed that dendrimer deposition was partially reversible for pH above 5.8. The acid-base properties of the dendrimer monolayers deposited on mica were characterized.

  18. Polychromatic transmissometer for in situ measurements of suspended particles and gelbstoff in water

    NASA Astrophysics Data System (ADS)

    Barth, Hans; Grisard, Klaus; Holtsch, Kurt; Reuter, Rainer; Stute, Uwe

    1997-10-01

    The beam attenuation coefficient is an optical parameter that sensitively depends on suspended and dissolved substances in water. Its measurement is not only of interest for an understanding of the radiative transfer in a water column. With appropriate algorithms for data interpretation, it also allows a fast determination of absorbing and scattering matter as time-series measurements or depth profiles that cannot easily be obtained with other methods. An instrument has been developed for measuring spectral attenuation coefficients over a wavelength range from 340 to 785 nm. The optical path length can be set between 0 and 400 mm. This allows application in a wide range of turbidity in coastal and inland (case 2 and case 3) waters and a calibration of the instrument during in-situ measurements. This makes the instrument suitable for long-term applications in which signals from conventional instruments would degrade owing to the biofouling of optical windows. From the data, the amount and the size distribution of suspended particles and the specific absorption of dissolved organic matter are derived in real time. Algorithms based on Monte Carlo methods are available for a classification of transparent particles and phytoplankton.

  19. A Novel Optical Diagnostic for In Situ Measurements of Lithium Polysulfides in Battery Electrolytes.

    PubMed

    Saqib, Najmus; Silva, Cody J; Maupin, C Mark; Porter, Jason M

    2017-01-01

    An optical diagnostic technique to determine the order and concentration of lithium polysulfides in lithium-sulfur (Li-S) battery electrolytes has been developed. One of the major challenges of lithium-sulfur batteries is the problem of polysulfide shuttling between the electrodes, which leads to self-discharge and loss of active material. Here we present an optical diagnostic for quantitative in situ measurements of lithium polysulfides using attenuated total reflection Fourier transform infrared (FT-IR) spectroscopy. Simulated infrared spectra of lithium polysulfide molecules were generated using computational quantum chemistry routines implemented in Gaussian 09. The theoretical spectra served as a starting point for experimental characterization of lithium polysulfide solutions synthesized by the direct reaction of lithium sulfide and sulfur. Attenuated total reflection FT-IR spectroscopy was used to measure absorption spectra. The lower limit of detection with this technique is 0.05 M. Measured spectra revealed trends with respect to polysulfide order and concentration, consistent with theoretical predictions, which were used to develop a set of equations relating the order and concentration of lithium polysulfides in a sample to the position and area of a characteristic infrared absorption band. The diagnostic routine can measure the order and concentration to within 5% and 0.1 M, respectively.

  20. In Situ Measurement and Prediction of Stresses and Strains During Casting of Steel

    NASA Astrophysics Data System (ADS)

    Galles, Daniel; Beckermann, Christoph

    2016-02-01

    Modeling the thermo-mechanical behavior of steel during casting is of great importance for the prediction of distortions and cracks. In this study, an elasto-visco-plastic constitutive law is calibrated with mechanical measurements from casting experiments. A steel bar is solidified in a sand mold and strained by applying a force to bolts that are embedded in the two ends of the bar. The temporal evolutions of the restraint force and the bar's length change are measured in situ. The experiments are simulated by inputting calculated transient temperature fields into a finite element stress analysis that employs the measured forces as boundary conditions. The thermal strain predictions are validated using data from experiments without a restraint. Initial estimates of the constitutive model parameters are obtained from available mechanical test data involving reheated steel specimens. The temperature dependence of the strain rate sensitivity exponent is then adjusted until the measured and predicted length changes of the strained bars agree. The resulting calibrated mechanical property dataset is valid for the high-temperature austenite phase of steel. The data reveal a significantly different mechanical behavior during casting compared to what the stress-strain data from reheated specimens show.