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Sample records for aircraft vertical profiles

  1. Optimization of the vertical flight profile on the flight management system for green aircraft

    NASA Astrophysics Data System (ADS)

    Felix Patron, Roberto Salvador

    To reduce aircraft's fuel consumption, a new method to calculate flight trajectories to be implemented in commercial Flight Management Systems has been developed. The aircraft's model was obtained from a flight performance database, which included experimental flight data. The optimized trajectories for three different commercial aircraft have been analyzed and developed in this thesis. To obtain the optimal flight trajectory that reduces the global flight cost, the vertical and the LNAV profiles have been studied and analyzed to find the aircraft's available speeds, possible flight altitudes and alternative horizontal trajectories that could reduce the global fuel consumption. A dynamic weather model has been implemented to improve the precision of the algorithm. This weather model calculates the speed and direction of wind, and the outside air temperature from a public weather database. To reduce the calculation time, different time-optimization algorithms have been implemented, such as the Golden Section search method, and different types of genetic algorithms. The optimization algorithm calculates the aircraft trajectory considering the departure and arrival airport coordinates, the aircraft parameters, the in-flight restrictions such as speeds, altitudes and WPs. The final output is given in terms of the flight time, fuel consumption and global flight cost of the complete flight. To validate the optimization algorithm results, the software FlightSIM RTM has been used. This software considers a complete aircraft aerodynamic model for its simulations, giving results that are accurate and very close to reality.

  2. Qualitative comparison of concurrent vertical optical turbulence profiles from an aircraft and balloons over White Sands Missile Range

    NASA Astrophysics Data System (ADS)

    Nowlin, Scott R.; Hahn, Ila L.; Hugo, Ronald J.; Bishop, Kenneth P.

    1999-08-01

    We report simultaneous balloon-borne thermosonde/airborne constant-current anemometer measurements made over a portion of White Sands Missile Range, NM. For the first time, vertical profiles of the refractive index structure parameter (Cn2) data generated from shallow slant aircraft flight paths are compared to the balloons vertical Cn2 distributions. We discuss possible adverse effects of meteorology and atmospheric velocity fluctuations. We present conclusions and make recommendations for future similar experimental efforts.

  3. OPTIM: Computer program to generate a vertical profile which minimizes aircraft fuel burn or direct operating cost. User's guide

    NASA Technical Reports Server (NTRS)

    1983-01-01

    A profile of altitude, airspeed, and flight path angle as a function of range between a given set of origin and destination points for particular models of transport aircraft provided by NASA is generated. Inputs to the program include the vertical wind profile, the aircraft takeoff weight, the costs of time and fuel, certain constraint parameters and control flags. The profile can be near optimum in the sense of minimizing: (1) fuel, (2) time, or (3) a combination of fuel and time (direct operating cost (DOC)). The user can also, as an option, specify the length of time the flight is to span. The theory behind the technical details of this program is also presented.

  4. Vertical Cloud Climatology During TC4 Derived from High-Altitude Aircraft Merged Lidar and Radar Profiles

    NASA Technical Reports Server (NTRS)

    Hlavka, Dennis; Tian, Lin; Hart, William; Li, Lihua; McGill, Matthew; Heymsfield, Gerald

    2009-01-01

    Aircraft lidar works by shooting laser pulses toward the earth and recording the return time and intensity of any of the light returning to the aircraft after scattering off atmospheric particles and/or the Earth s surface. The scattered light signatures can be analyzed to tell the exact location of cloud and aerosol layers and, with the aid of a few optical assumptions, can be analyzed to retrieve estimates of optical properties such as atmospheric transparency. Radar works in a similar fashion except it sends pulses toward earth at a much larger wavelength than lidar. Radar records the return time and intensity of cloud or rain reflection returning to the aircraft. Lidar can measure scatter from optically thin cirrus and aerosol layers whose particles are too small for the radar to detect. Radar can provide reflection profiles through thick cloud layers of larger particles that lidar cannot penetrate. Only after merging the two instrument products can accurate measurements of the locations of all layers in the full atmospheric column be achieved. Accurate knowledge of the vertical distribution of clouds is important information for understanding the Earth/atmosphere radiative balance and for improving weather/climate forecast models. This paper describes one such merged data set developed from the Tropical Composition, Cloud and Climate Coupling (TC4) experiment based in Costa Rica in July-August 2007 using the nadir viewing Cloud Physics Lidar (CPL) and the Cloud Radar System (CRS) on board the NASA ER-2 aircraft. Statistics were developed concerning cloud probability through the atmospheric column and frequency of the number of cloud layers. These statistics were calculated for the full study area, four sub-regions, and over land compared to over ocean across all available flights. The results are valid for the TC4 experiment only, as preferred cloud patterns took priority during mission planning. The TC4 Study Area was a very cloudy region, with cloudy

  5. Observed Variability in CO2 Column Abundances from aircraft vertical profiles: Insight into future space-based mission requirements

    NASA Astrophysics Data System (ADS)

    Choi, Y.; Kooi, S. A.; Vay, S. A.; Browell, E. V.

    2011-12-01

    This presentation discusses the use of high-resolution in-situ CO2 data to quantify the variability in tropospheric CO2 column optical depth. CO2 column abundances are derived from vertical soundings executed during several large-scale airborne campaigns over different geographic regions and seasons spanning the eastern United States (INTEX-NA summer 2004); Mexico (MILAGRO March 2006); the eastern North Pacific and Alaska (INTEX-B May 2006); the Canadian Arctic (ARCTAS spring and summer 2008); and California (CARB June 2008). Data from smaller-scale field experiments associated with the calibration/validation activities of a new active remote CO2 sensor for ASCENDS (Active Sensing of CO2 Emissions over Nights, Days, and Seasons) conducted over OK, MI, NH, VA, and CA, since 2005, are also examined. Nominal weighting functions for ASCENDS measurements of CO2 in the 1.57- and 2.0-microns regions are used to convert the observed CO2 mixing ratio profiles to column optical depths. Using statistics calculated from these optical depths, we show the variability of the CO2 columns and how it relates to the measurement requirements for future space-based missions.

  6. Vertical flight path steering system for aircraft

    NASA Technical Reports Server (NTRS)

    Lambregts, Antonius A. (Inventor)

    1983-01-01

    Disclosed is a vertical flight path angle steering system for aircraft, utilizing a digital flight control computer which processes pilot control inputs and aircraft response parameters into suitable elevator commands and control information for display to the pilot on a cathode ray tube. The system yields desirable airplane control handling qualities and responses as well as improvements in pilot workload and safety during airplane operation in the terminal area and under windshear conditions.

  7. Offset vertical radar profiling

    USGS Publications Warehouse

    Witten, A.; Lane, J.

    2003-01-01

    Diffraction tomography imaging was applied to VRP data acquired by vertically moving a receiving antenna in a number of wells. This procedure simulated a vertical downhole receiver array. Similarly, a transmitting antenna was sequentially moved along a series of radial lines extending outward from the receiver wells. This provided a sequence of multistatic data sets and, from each data set, a two-dimensional vertical cross-sectional image of spatial variations in wave speed was reconstructed.

  8. Vertical tail buffeting of fighter aircraft

    NASA Astrophysics Data System (ADS)

    Lee, B. H. K.

    2000-04-01

    Vertical tail buffeting at high angles of attack is a phenomenon associated with the impact of vortical flows generated by the aircraft on the fins. This poses a serious problem for both single- and twin-tail fighter aircraft from the point of view of combat maneuverability and structural integrity. The research activities to understand the flow physics with an aim to alleviate buffet loads were quite intense during the period from the late 1970s to the early 1990s. Most of the investigations were carried out on the F/A-18 mainly because of two international programs involving countries that operate the F/A-18 in their air force. This review begins with a description of the water tunnel experiments showing some flow visualization results of the leading-edge extension (LEX) burst vortical flows. Wind tunnel studies on a 1/9 scale F/A-18 model in Australia, a 1/6.65 scale model in the United Kingdom, a 6% scale model in Canada, 12%, 16% and full-scale models in the United States are summarized. Scale effects can be deduced from the various sub- and full-scale models tested. Flight test results conducted on the High Alpha Research Vehicle in the United States and on an instrumented CF-18 test aircraft in Canada are presented. The accuracy of analytical methods utilizing wind tunnel data to predict buffet loads at flight conditions is discussed. The use of CFD to compute vertical fin buffeting is challenging and requires a large amount of computing power. A brief exposure to the methodology is given and results from the only available computational case study carried out by NASA Ames are compared with wind tunnel and flight test data. A short introduction to statistical non-stationary effects is given. Hysteresis effect of the LEX vortex burst on the buffet loads is discussed, and a statistical non-stationary buffet prediction method is outlined. This review provides a useful reference to the results collected from the High Alpha Technology Program, The Technical

  9. Aircraft vertical profiles of trace gas and aerosol pollution over the mid-Atlantic United States: Statistics and meteorological cluster analysis

    NASA Astrophysics Data System (ADS)

    Taubman, B. F.; Hains, J. C.; Thompson, A. M.; Marufu, L. T.; Doddridge, B. G.; Stehr, J. W.; Piety, C. A.; Dickerson, R. R.

    2006-05-01

    From 1997 to 2003, airborne measurements of O3, CO, SO2, and aerosol properties were made during summertime air pollution episodes over the mid-Atlantic United States (34.7-44.6°N, 68.4-81.6°W) as part of the Regional Atmospheric Measurement, Modeling, and Prediction Program (RAMMPP). Little diurnal variation was identified in the CO, SO2, and Ångström exponent profiles, although the Ångström exponent profiles decreased with altitude. Boundary layer O3 was greater in the afternoon, while lower free tropospheric O3 was invariant at ˜55 ppbv. The single scattering albedo increased from morning to afternoon (0.93 ± 0.01-0.94 ± 0.01); however, both profiles decreased with altitude. A cluster analysis of back trajectories in conjunction with the vertical profile data was used to identify source regions and characteristic transport patterns during summertime pollution episodes. When the greatest trajectory density lay over the northern Ohio River Valley, the result was large O3 values, large SO2/CO ratios, highly scattering particles, and large aerosol optical depths. Maximum trajectory density over the southern Ohio River Valley resulted in little pollution. The greatest afternoon O3 values occurred during periods of stagnation. North-northwesterly and northerly flow brought the least pollution overall. The contribution of regional transport to afternoon boundary layer O3 was quantified. When the greatest cluster trajectory density lay over the Ohio River Valley (˜59% of the profiles), transport accounted for 69-82% of the afternoon boundary layer O3. Under stagnant conditions (˜27% of the profiles), transport only accounted for 58% of the afternoon boundary layer O3. The results from this study provide a description of regional chemical and transport processes that will be valuable to investigators from the Baltimore, New York, and Pittsburgh EPA Supersites.

  10. Longitudinal variability of black carbon vertical profiles

    NASA Astrophysics Data System (ADS)

    Schwarz, J. P.; Weinzierl, B.; Samset, B. H.; Perring, A. E.; Dollner, M.; Heimerl, K.; Markovic, M. Z.; Ziemba, L. D.

    2015-12-01

    Black carbon (BC) aerosol contributes substantially to both climate forcing and climate forcing uncertainty. An important source of this uncertainty derives from the difficulty in predicting BC's global abundance and vertical distribution. Here we present a multi-year record of black carbon (BC) vertical concentration profiles from both sides of the Atlantic, obtained from airborne Single Particle Soot Photometers (SP2s) flown on the NASA DC-8, and the DLR Falcon research aircraft from the CONCERT, ACCESS, DC3, SEAC4RS, and SALTRACE campaigns. The measurements constrain the relative rates of BC transport/removal from, and zonal mixing in, the upper troposphere, as well as the range of BC loadings in these regions. They also constrain the time-rates of change of BC loads in altitudes at which it is a highly efficient (although sparse) climate forcer, and a relatively long-lived aerosol tracer. We find that concentration of BC in the upper troposphere can vary by a factor 10. Over the Northern mid-latitudes concentrations are however consistent to a fraction of this range over wide longitudinal ranges, over month-long timescales. The data show that BC becomes zonally mixed here starting at 500 hPa and extending to near the tropopause. These results imply broader value than previously associated with measured vertical profiles in constraining global scale BC loadings aloft.

  11. Evaluation of vertical profiles to design continuous descent approach procedure

    NASA Astrophysics Data System (ADS)

    Pradeep, Priyank

    The current research focuses on predictability, variability and operational feasibility aspect of Continuous Descent Approach (CDA), which is among the key concepts of the Next Generation Air Transportation System (NextGen). The idle-thrust CDA is a fuel economical, noise and emission abatement procedure, but requires increased separation to accommodate for variability and uncertainties in vertical and speed profiles of arriving aircraft. Although a considerable amount of researches have been devoted to the estimation of potential benefits of the CDA, only few have attempted to explain the predictability, variability and operational feasibility aspect of CDA. The analytical equations derived using flight dynamics and Base of Aircraft and Data (BADA) Total Energy Model (TEM) in this research gives insight into dependency of vertical profile of CDA on various factors like wind speed and gradient, weight, aircraft type and configuration, thrust settings, atmospheric factors (deviation from ISA (DISA), pressure and density of the air) and descent speed profile. Application of the derived equations to idle-thrust CDA gives an insight into sensitivity of its vertical profile to multiple factors. This suggests fixed geometric flight path angle (FPA) CDA has higher degree of predictability and lesser variability at the cost of non-idle and low thrust engine settings. However, with optimized design this impact can be overall minimized. The CDA simulations were performed using Future ATM Concept Evaluation Tool (FACET) based on radar-track and aircraft type data (BADA) of the real air-traffic to some of the busiest airports in the USA (ATL, SFO and New York Metroplex (JFK, EWR and LGA)). The statistical analysis of the vertical profiles of CDA shows 1) mean geometric FPAs derived from various simulated vertical profiles are consistently shallower than 3° glideslope angle and 2) high level of variability in vertical profiles of idle-thrust CDA even in absence of

  12. Vertical grid of retrieved atmospheric profiles

    NASA Astrophysics Data System (ADS)

    Ceccherini, Simone; Carli, Bruno; Raspollini, Piera

    2016-05-01

    The choice of the vertical grid of atmospheric profiles retrieved from remote sensing observations is discussed considering the two cases of profiles used to represent the results of individual measurements and of profiles used for subsequent data fusion applications. An ozone measurement of the MIPAS instrument is used to assess, for different vertical grids, the quality of the retrieved profiles in terms of profile values, retrieval errors, vertical resolutions and number of degrees of freedom. In the case of individual retrievals no evident advantage is obtained with the use of a grid finer than the one with a reduced number of grid points, which are optimized according to the information content of the observations. Nevertheless, this instrument dependent vertical grid, which seems to extract all the available information, provides very poor results when used for data fusion applications. A loss of about a quarter of the degrees of freedom is observed when the data fusion is made using the instrument dependent vertical grid relative to the data fusion made using a vertical grid optimized for the data fusion product. This result is explained by the analysis of the eigenvalues of the Fisher information matrix and leads to the conclusion that different vertical grids must be adopted when data fusion is the expected application.

  13. Surface tension profiles in vertical soap films

    NASA Astrophysics Data System (ADS)

    Adami, N.; Caps, H.

    2015-01-01

    Surface tension profiles in vertical soap films are experimentally investigated. Measurements are performed by introducing deformable elastic objets in the films. The shape adopted by those objects once set in the film is related to the surface tension value at a given vertical position by numerically solving the adapted elasticity equations. We show that the observed dependency of the surface tension versus the vertical position is predicted by simple modeling that takes into account the mechanical equilibrium of the films coupled to previous thickness measurements.

  14. Preliminary design of a supersonic Short Takeoff and Vertical Landing (STOVL) fighter aircraft

    NASA Technical Reports Server (NTRS)

    Cox, Brian; Borchers, Paul; Gomer, Charlie; Henderson, Dean; Jacobs, Tavis; Lawson, Todd; Peterson, Eric; Ross, Tweed, III; Bellmard, Larry

    1990-01-01

    The preliminary design study of a supersonic Short Takeoff and Vertical Landing (STOVL) fighter is presented. A brief historical survey of powered lift vehicles was presented, followed by a technology assessment of the latest supersonic STOVL engine cycles under consideration by industry and government in the U.S. and UK. A survey of operational fighter/attack aircraft and the modern battlefield scenario were completed to develop, respectively, the performance requirements and mission profiles for the study. Three configurations were initially investigated with the following engine cycles: a hybrid fan vectored thrust cycle, a lift+lift/cruise cycle, and a mixed flow vectored thrust cycle. The lift+lift/cruise aircraft configuration was selected for detailed design work which consisted of: (1) a material selection and structural layout, including engine removal considerations, (2) an aircraft systems layout, (3) a weapons integration model showing the internal weapons bay mechanism, (4) inlet and nozzle integration, (5) an aircraft suckdown prediction, (6) an aircraft stability and control analysis, including a takeoff, hover, and transition control analysis, (7) a performance and mission capability study, and (8) a life cycle cost analysis. A supersonic fighter aircraft with STOVL capability with the lift+lift/cruise engine cycle seems a viable option for the next generation fighter.

  15. RSRA vertical drag test report. [rotor systems research aircraft

    NASA Technical Reports Server (NTRS)

    Flemming, R. J.

    1981-01-01

    The Rotor Systems Research Aircraft (RSRA), because of its ability to measure rotor loads, was used to conduct an experiment to determine vertical drag, tail rotor blockage, and thrust augmentation as affected by ground clearance and flight velocity. The RSRA was flown in the helicopter configuration at speeds from 0 to 15 knots for wheel heights from 5 to 150 feet, and to 60 knots out of ground effect. The vertical drag trends in hover, predicted by theory and shown in model tests, were generally confirmed. The OGE hover vertical drag is 4.0 percent, 1.1 percent greater than predicted. The vertical drag decreases rapidly as wheel height is reduced, and is zero at a wheel height of 6 feet. The vertical drag also decreases with forward speed, approaching zero at sixty knots. The test data show the effect of wheel height and forward speed on thrust, gross weight capability, and power, and provide the relationships for power and collective pitch at constant gross weight required for the simulation of helicopter takeoffs and landings.

  16. Unsteady aerodynamic characterization of a military aircraft in vertical gusts

    NASA Technical Reports Server (NTRS)

    Lebozec, A.; Cocquerez, J. L.

    1985-01-01

    The effects of 2.5-m/sec vertical gusts on the flight characteristics of a 1:8.6 scale model of a Mirage 2000 aircraft in free flight at 35 m/sec over a distance of 30 m are investigated. The wind-tunnel setup and instrumentation are described; the impulse-response and local-coefficient-identification analysis methods applied are discussed in detail; and the modification and calibration of the gust-detection probes are reviewed. The results are presented in graphs, and good general agreement is obtained between model calculations using the two analysis methods and the experimental measurements.

  17. Advanced composite vertical stabilizer for DC-10 transport aircraft

    NASA Technical Reports Server (NTRS)

    Stephens, C. O.

    1979-01-01

    Structural design, tooling, fabrication, and test activities are reported for a program to develop an advanced composite vertical stabilizer (CVS) for the DC 10 Commercial Transport Aircraft. Structural design details are described and the status of structural and weight analyses are reported. A structural weight reduction of 21.7% is currently predicted. Test results are discussed for sine wave stiffened shear webs containing representative of the CVS spar webs and for lightning current transfer and tests on a panel representative of the CVS skins.

  18. Vertical profiling of air pollution at RAPCD

    NASA Astrophysics Data System (ADS)

    Newchurch, Michael J.; Fuller, Kirk A.; Bowdle, David A.; Johnson, Steven; McNider, Richard T.; Knupp, Kevin; Lapenta, Bill; Gillani, Noor; Biazar, Arastoo; Burris, John

    2004-09-01

    Local and regional pollution interact at the interface between the Planetary Boundary Layer and the Free Troposphere. The vertical distributions of ozone, aerosols, and winds must be measured with high temporal and vertical resolution to characterize this interchange and ultimately to accurately forecast ozone and aerosol pollution. To address this critical issue, the Regional Atmospheric Profiling Center for Discovery (RAPCD) was built and instrumented in the National Space Science and Technology Center on the UAH campus. The UV DIAL ozone lidar, Nd:YAG aerosol lidar, and 2-micron Doppler wind lidar, along with balloon-borne ECC ozonesondes, form the core of the RAPCD instrumentation for studying this problem. Instrumentation in the associated Mobile Integrated Profiling (MIPS) laboratory includes a 915Mhz profiler, sodar, and ceilometer. The collocated Applied Micro-particle Optics and Radiometry (AμOR) laboratory hosts the FTIR, MOUDI, and optical particle counter. Using MODELS-3 analysis by colleagues, and cooperative ventures with the co-located National Weather Service Forecasting Office in Huntsville, AL, we are developing a unique facility for advancing the state-of-the-science in pollution forecasting.

  19. Vertical Profiling of Air Pollution at RAPCD

    NASA Technical Reports Server (NTRS)

    Newchurch, Michael J.; Fuller, Kirk A.; Bowdle, David A.; Johnson, Steven; Knupp, Kevin; Gillani, Noor; Biazar, Arastoo; Mcnider, Richard T.; Burris, John

    2004-01-01

    The interaction between local and regional pollution levels occurs at the interface of the Planetary Boundary Layer and the Free Troposphere. Measuring the vertical distribution of ozone, aerosols, and winds with high temporal and vertical resolution is essential to diagnose the nature of this interchange and ultimately for accurately forecasting ozone and aerosol pollution levels. The Regional Atmospheric Profiling Center for Discovery, RAPCD, was built and instrumented to address this critical issue. The ozone W DIAL lidar, Nd:YAG aerosol lidar, and 2.1 micron Doppler wind lidar, along with balloon- borne ECC ozonesondes form the core of the W C D instrumentation for addressing this problem. Instrumentation in the associated Mobile Integrated Profiling (MIPS) laboratory includes 91 5Mhz profiler, sodar, and ceilometer. The collocated Applied particle Optics and Radiometry (ApOR) laboratory hosts an FTIR along with MOUDI and optical particle counters. With MODELS-3 analysis by colleagues in the National Space Science and Technology Center on the UAH campus and the co- located National Weather Service Forecasting Office in Huntsville, AL we are developing a unique facility for advancing the state of the science of pollution forecasting.

  20. So2 vertical profile on Venus

    NASA Astrophysics Data System (ADS)

    Duricic, Alen; Leitner, Johannes; Firneis, Maria G.

    2010-05-01

    Introduction The distribution of SO2 below the clouds of Venus is an unsettled matter because various entry probes and earth observed values show big differences for the same altitude levels. A new analysis of the SO2 vertical profile with a 'best of' data set [1] is compared to the Vega 1 and Vega 2 results. For the analysis of the SO2 vertical profile two models have been formulated. While one model considers the fast decrease of SO2 with descending altitude and starts with 0 ppmV at the surface, the other model starts with 25 ppmV, as indicated by Vega 1. Although there is a lack of information on the lowest 10 kms of the atmosphere, an analysis should be done to understand the geological evolution and a possible activity on Venus. Vertical Profiles The two models produce two different vertical profiles and with those it was possible to calculate the mass of SO2 in the whole lower atmosphere. It is important to note that SO2 nearly disappears at 69 km height [1,3] while 99,6% of the whole mass is still contained in the lower atmosphere. The difference in the results is based on the different surface values, which have been used. The first model stands in good agreement with the Vega mission data and the second model can be used as an upper limit of SO2 in the atmosphere. The results yield a good estimation of how much SO2 is existent and give new discussion points about volcanic activity on Venus and a possible still unknown SO2 destroying mechanism. References [1] Bertaux, J. et al. (1996) JGR, 101, 12709-12745. [2] de Bergh, C. et al. (2006) Planetary and Space Sci., 54, 1389-1397. [3] Esposito L.W. et al., (1997) Venus II : Geology, Geophysics, Atmosphere, and Solar Wind Environment. Edited by Stephen W. Bougher, D.M. Hunten, and R.J. Philips. Tucson, AZ : University of Arizona Press, 415-458

  1. Radially Magnetized Protoplanetary Disk: Vertical Profile

    NASA Astrophysics Data System (ADS)

    Russo, Matthew; Thompson, Christopher

    2015-11-01

    This paper studies the response of a thin accretion disk to an external radial magnetic field. Our focus is on protoplanetary disks (PPDs), which are exposed during their later evolution to an intense, magnetized wind from the central star. A radial magnetic field is mixed into a thin surface layer, wound up by the disk shear, and pushed downward by a combination of turbulent mixing and ambipolar and ohmic drift. The toroidal field reaches much greater strengths than the seed vertical field that is usually invoked in PPD models, even becoming superthermal. Linear stability analysis indicates that the disk experiences the magnetorotational instability (MRI) at a higher magnetization than a vertically magnetized disk when both the effects of ambipolar and Hall drift are taken into account. Steady vertical profiles of density and magnetic field are obtained at several radii between 0.06 and 1 AU in response to a wind magnetic field Br ˜ (10-4-10-2)(r/ AU)-2 G. Careful attention is given to the radial and vertical ionization structure resulting from irradiation by stellar X-rays. The disk is more strongly magnetized closer to the star, where it can support a higher rate of mass transfer. As a result, the inner ˜1 AU of a PPD is found to evolve toward lower surface density. Mass transfer rates around 10-8 M⊙ yr-1 are obtained under conservative assumptions about the MRI-generated stress. The evolution of the disk and the implications for planet migration are investigated in the accompanying paper.

  2. Vertical Profiles of Aerosol Optical Properties Over Central Illinois and Comparison with Surface and Satellite Measurements

    NASA Technical Reports Server (NTRS)

    Sheridan P. J.; Andrews, E.; Ogren, J A.; Tackett, J. L.; Winker, D. M.

    2012-01-01

    Between June 2006 and September 2009, an instrumented light aircraft measured over 400 vertical profiles of aerosol and trace gas properties over eastern and central Illinois. The primary objectives of this program were to (1) measure the in situ aerosol properties and determine their vertical and temporal variability and (2) relate these aircraft measurements to concurrent surface and satellite measurements. Underflights of the CALIPSO satellite show reasonable agreement in a majority of retrieved profiles between aircraft-measured extinction at 532 nm (adjusted to ambient relative humidity) and CALIPSO-retrieved extinction, and suggest that routine aircraft profiling programs can be used to better understand and validate satellite retrieval algorithms. CALIPSO tended to overestimate the aerosol extinction at this location in some boundary layer flight segments when scattered or broken clouds were present, which could be related to problems with CALIPSO cloud screening methods. The in situ aircraft-collected aerosol data suggest extinction thresholds for the likelihood of aerosol layers being detected by the CALIOP lidar. These statistical data offer guidance as to the likelihood of CALIPSO's ability to retrieve aerosol extinction at various locations around the globe.

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

    PubMed

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

    2015-08-01

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

  4. Vertical profile measurements of lower troposphere ionisation

    NASA Astrophysics Data System (ADS)

    Harrison, R. G.; Nicoll, K. A.; Aplin, K. L.

    2014-11-01

    Vertical soundings of the atmospheric ion production rate have been obtained from Geiger counters integrated with conventional meteorological radiosondes. In launches made from Reading (UK) during 2013-2014, the Regener-Pfotzer ionisation maximum was at an altitude equivalent to a pressure of (63.1±2.4) hPa, or, expressed in terms of the local air density, (0.101±0.005) kg m-3. The measured ionisation profiles have been evaluated against the Usoskin-Kovaltsov model and, separately, surface neutron monitor data from Oulu. Model ionisation rates agree well with the observed cosmic ray ionisation below 20 km altitude. Above 10 km, the measured ionisation rates also correlate well with simultaneous neutron monitor data, although, consistently with previous work, measured variability at the ionisation maximum is greater than that found by the neutron monitor. However, in the lower atmosphere (below 5 km altitude), agreement between the measurements and simultaneous neutron monitor data is poor. For studies of transient lower atmosphere phenomena associated with cosmic ray ionisation, this indicates the need for in situ ionisation measurements and improved lower atmosphere parameterisations.

  5. Tropospheric mercury vertical profiles between 500 and 10 000 m in central Europe

    NASA Astrophysics Data System (ADS)

    Weigelt, Andreas; Ebinghaus, Ralf; Pirrone, Nicola; Bieser, Johannes; Bödewadt, Jan; Esposito, Giulio; Slemr, Franz; van Velthoven, Peter F. J.; Zahn, Andreas; Ziereis, Helmut

    2016-03-01

    The knowledge of the vertical distribution of atmospheric mercury (Hg) plays an important role in determining the transport and cycling of mercury. However, measurements of the vertical distribution are rare, because airborne measurements are expensive and labour intensive. Consequently, only a few vertical Hg profile measurements have been reported since the 1970s. Besides the Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container (CARIBIC) observations, the latest vertical profile over Europe was measured in 1996. Within the Global Mercury Observation System (GMOS) project, four vertical profiles were taken on board research aircraft (CASA-212) in August 2013 in background air over different locations in Slovenia and Germany. Each vertical profile consists of at least seven 5 min horizontal flight sections from 500 m above ground to 3000 m a.s.l. Gaseous elemental mercury (GEM) and total gaseous mercury (TGM) were measured with Tekran 2537X and Tekran 2537B analysers. In addition to the mercury measurements, SO2, CO, O3, NO, and NO2, basic meteorological parameters (pressure, temperature, relative humidity) have been measured. Additional ground-based mercury measurements at the GMOS master site in Waldhof, Germany and measurements onboard the CARIBIC passenger aircraft were used to extend the profile to the ground and upper troposphere respectively. No vertical gradient was found inside the well-mixed boundary layer (variation of less than 0.1 ng m-3) at different sites, with GEM varying from location to location between 1.4 and 1.6 ng m-3 (standard temperature and pressure, STP: T = 273.15 K, p = 1013.25 hPa). At all locations GEM dropped to 1.3 ng m-3 (STP) when entering the free troposphere and remained constant at higher altitudes. The combination of the vertical profile, measured on 21 August 2013 over Leipzig, Germany, with the CARIBIC measurements during ascent and descent to Frankfurt Airport, Germany, taken at

  6. Application of thrusting ejectors to tactical aircraft having vertical lift and short-field capability

    NASA Technical Reports Server (NTRS)

    Koenig, D. G.; Stoll, F.; Aoyagi, K.

    1981-01-01

    The status of ejector development in terms of application to V/STOL aircraft is reported in three categories: aircraft systems and ejector concepts; ejector performance including prediction techniques and experimental data base available; and, integration of the ejector with complete aircraft configurations. Available prediction techniques are reviewed and performance of three ejector designs with vertical lift capability is summarized. Applications of the 'fuselage' and 'short diffuser' ejectors to fighter aircraft are related to current and planned research programs. Recommendations are listed for effort needed to evaluate installed performance.

  7. Computer programs for generation and evaluation of near-optimum vertical flight profiles

    NASA Technical Reports Server (NTRS)

    Sorensen, J. A.; Waters, M. H.; Patmore, L. C.

    1983-01-01

    Two extensive computer programs were developed. The first, called OPTIM, generates a reference near-optimum vertical profile, and it contains control options so that the effects of various flight constraints on cost performance can be examined. The second, called TRAGEN, is used to simulate an aircraft flying along an optimum or any other vertical reference profile. TRAGEN is used to verify OPTIM's output, examine the effects of uncertainty in the values of parameters (such as prevailing wind) which govern the optimum profile, or compare the cost performance of profiles generated by different techniques. A general description of these programs, the efforts to add special features to them, and sample results of their usage are presented.

  8. Moving-base simulation evaluation of thrust margins for vertical landing for the NASA YAV-8B Harrier aircraft

    NASA Technical Reports Server (NTRS)

    Franklin, James A.; Stortz, Michael W.

    1993-01-01

    A simulation experiment was conducted on Ames Research Center's Vertical Motion Simulator to evaluate the thrust margin for vertical landing required for the YAV-8B Harrier. Two different levels of ground effect were employed, representing the aircraft with or without lift improvement devices installed. In addition, two different inlet temperature profiles were included to cover a wide range of hot gas ingestion. For each ground effect and hot gas ingestion variant, vertical landings were performed at successively heavier weights, with the pilot assessing the acceptability of the operation in each case. Results are presented as a function of hover weight ratio and a metric of the mean ground effect and ingestion that reflect the increase in thrust margin required to provide acceptable control of sink rate during the descent to touchdown with increasing suck down and hot gas ingestion.

  9. Development and evaluation of a profile negotiation process for integrating aircraft and air traffic control automation

    NASA Technical Reports Server (NTRS)

    Green, Steven M.; Denbraven, Wim; Williams, David H.

    1993-01-01

    The development and evaluation of the profile negotiation process (PNP), an interactive process between an aircraft and air traffic control (ATC) that integrates airborne and ground-based automation capabilities to determine conflict-free trajectories that are as close to an aircraft's preference as possible, are described. The PNP was evaluated in a real-time simulation experiment conducted jointly by NASA's Ames and Langley Research Centers. The Ames Center/TRACON Automation System (CTAS) was used to support the ATC environment, and the Langley Transport Systems Research Vehicle (TSRV) piloted cab was used to simulate a 4D Flight Management System (FMS) capable aircraft. Both systems were connected in real time by way of voice and data lines; digital datalink communications capability was developed and evaluated as a means of supporting the air/ground exchange of trajectory data. The controllers were able to consistently and effectively negotiate nominally conflict-free vertical profiles with the 4D-equipped aircraft. The actual profiles flown were substantially closer to the aircraft's preference than would have been possible without the PNP. However, there was a strong consensus among the pilots and controllers that the level of automation of the PNP should be increased to make the process more transparent. The experiment demonstrated the importance of an aircraft's ability to accurately execute a negotiated profile as well as the need for digital datalink to support advanced air/ground data communications. The concept of trajectory space is proposed as a comprehensive approach for coupling the processes of trajectory planning and tracking to allow maximum pilot discretion in meeting ATC constraints.

  10. Inter-comparison of CALIPSO and CloudSat retrieved profiles of aerosol and cloud microphysical parameters with aircraft profiles over a tropical region

    NASA Astrophysics Data System (ADS)

    Padmakumari, B.; Harikishan, G.; Maheskumar, R. S.

    2016-05-01

    Satellites play a major role in understanding the spatial and vertical distribution of aerosols and cloud microphysical parameters over a large area. However, the inherent limitations in satellite retrievals can be improved through inter-comparisons with airborne platforms. Over the Indian sub-continent, the vertical profiles retrieved from space-borne lidar such as CALIOP (Cloud-Aerosol LIdar with Orthogonal Polarization) on board the satellite CALIPSO and Cloud Profiling Radar (CPR) on board the satellite CloudSat were inter- compared with the aircraft observations conducted during Cloud Aerosol Interactions and Precipitation Enhancement Experiment (CAIPEEX). In the absence of high clouds, both aircraft and CALIOP showed similar features of aerosol layering and water-ice cloud signatures. As CALIOP could not penetrate the thick clouds, the aerosol information below the cloud is missed. While the aircraft could measure high concentrations below the cloud base and above the low clouds in the presence of high clouds. The aircraft derived liquid water content (LWC) and droplet effective radii (Re) showed steady increase from cloud base to cloud top with a variable cloud droplet number concentration (CDNC). While the CloudSat derived LWC, CDNC and Re showed increase from the cloud top to cloud base in contradiction to the aircraft measurements. The CloudSat profiles are underestimated as compared to the corresponding aircraft profiles. Validation of satellite retrieved vertical profiles with aircraft measurements is very much essential over the tropics to improve the retrieval algorithms and to constrain the uncertainties in the regional cloud parameterization schemes.

  11. Tropospheric mercury vertical profiles between 500 and 10 000 m in central Europe

    NASA Astrophysics Data System (ADS)

    Weigelt, A.; Ebinghaus, R.; Pirrone, N.; Bieser, J.; Bödewadt, J.; Esposito, G.; Slemr, F.; van Velthoven, P. F. J.; Zahn, A.; Ziereis, H.

    2015-10-01

    Measurements of the vertical distribution of atmospheric mercury (Hg) are rare, because airborne measurements are expensive and labour intensive. Consequently, only a few vertical Hg profile measurements have been reported since the 1970s. Besides the CARIBIC passenger aircraft observations, the latest vertical profile over Europe was measured in 1996. Within the Global Mercury Observation System (GMOS) project four vertical profiles were taken on board research aircraft (CASA-212) in August 2013 in background air over different locations in Slovenia and Germany. Each vertical profile consists of at least seven 5 min horizontal flight sections from 500 m above ground to 3000 m a.s.l. Gaseous elemental mercury (GEM) was measured with a Tekran 2537X analyser and a Lumex RA-915-AM. Total gaseous mercury (TGM) was measured using a Tekran 2537B analyser and gaseous oxidized mercury (GOM) was sampled onto 8 denuders for post flight analysis (one for each profile, three during the transfer flights, and two blanks). In addition to the mercury measurements, SO2, CO, O3, NO, NO2, as well as basic meteorological parameters (pressure, temperature, relative humidity) have been measured. Additional ground based speciated mercury measurements at the GMOS master site in Waldhof (Germany) were used to extend the profile to the ground. No vertical gradient was found inside the well mixed boundary layer (variation by less than 0.1 ng m-3) at different sites with GEM varying from location to location between 1.4 and 1.6 ng m-3 (STP; standard conditions: p = 1013.25 hPa, T = 273.15 K). At all locations GEM dropped to 1.3 ng m-3 (STP) when entering the free troposphere and remained constant at higher altitudes. The combination of the vertical profile, measured on 21 August 2013, over Leipzig (Germany) with the CARIBIC measurements during ascent and descent to Frankfurt airport (Germany) at approximately the same time provide a unique central European vertical profile from inside the

  12. The space-developed dynamic vertical cutoff rigidity model and its applicability to aircraft radiation dose.

    PubMed

    Smart, D F; Shea, M A

    2003-01-01

    We have developed a dynamic geomagnetic vertical cutoff rigidity model that predicts the energetic charged particle transmission through the magnetosphere. Initially developed for space applications, we demonstrate the applicability of this library of cutoff rigidity models for computing aircraft radiation dose. The world grids of vertical cutoff rigidities were obtained by particle trajectory tracing in a magnetospheric model. This reference set of world grids of vertical cutoff rigidities calculated for satellite altitudes covers all magnetic activity levels from super quiet to extremely disturbed (i.e., Kp indices ranging from 0 to 9+) for every three hours in universal time. We utilize the McIlwain "L" parameter as the basis of the interpolation technique to reduce these initial satellite altitude vertical cutoff rigidities to cutoff rigidity values at aircraft altitudes.

  13. Advanced composite vertical stabilizer for DC-10 transport aircraft

    NASA Technical Reports Server (NTRS)

    Stephens, C. O.

    1978-01-01

    The structural design configuration for the Composite Vertical Stabilizer is described and the structural design, analysis, and weight activities are presented. The status of fabrication and test activities for the development test portion of the program is described. Test results are presented for the skin panels, spar web, spar cap to cover, and laminate properties specimens. Engineering drawings of vertification test panels and root fittings, rudder support specimens, titanium fittings, and rear spar specimen analysis models are included.

  14. Vertical profile of 137Cs in soil.

    PubMed

    Krstić, D; Nikezić, D; Stevanović, N; Jelić, M

    2004-12-01

    In this paper, a vertical distribution of 137Cs in undisturbed soil was investigated experimentally and theoretically. Soil samples were taken from the surroundings of the city of Kragujevac in central Serbia during spring-summer of 2001. The sampling locations were chosen in such a way that the influence of soil characteristics on depth distribution of 137Cs in soil could be investigated. Activity of 137Cs in soil samples was measured using a HpGe detector and multi-channel analyzer. Based on vertical distribution of 137Cs in soil which was measured for each of 10 locations, the diffusion coefficient of 137Cs in soil was determined. In the next half-century, 137Cs will remain as the source of the exposure. Fifteen years after the Chernobyl accident, and more than 30 years after nuclear probes, the largest activity of 137Cs is still within 10 cm of the upper layer of the soil. This result confirms that the penetration of 137Cs in soil is a very slow process. Experimental results were compared with two different Green functions and no major differences were found between them. While both functions fit experimental data well in the upper layer of soil, the fitting is not so good in deeper layers. Although the curves obtained by these two functions are very close to each other, there are some differences in the values of parameters acquired by them. PMID:15388151

  15. Piloting Vertical Flight Aircraft: A Conference on Flying Qualities and Human Factors

    NASA Technical Reports Server (NTRS)

    Blanken, Christopher L. (Editor); Whalley, Matthew S. (Editor)

    1993-01-01

    This document contains papers from a specialists' meeting entitled 'Piloting Vertical Flight Aircraft: A Conference on Flying Qualities and Human Factors.' Vertical flight aircraft, including helicopters and a variety of Vertical Takeoff and Landing (VTOL) concepts, place unique requirements on human perception, control, and performance for the conduct of their design missions. The intent of this conference was to examine, for these vehicles, advances in: (1) design of flight control systems for ADS-33C standards; (2) assessment of human factors influences of cockpit displays and operational procedures; (3) development of VTOL design and operational criteria; and (4) development of theoretical methods or models for predicting pilot/vehicle performance and mission suitability. A secondary goal of the conference was to provide an initial venue for enhanced interaction between human factors and handling qualities specialists.

  16. The Vertical Profile of Ocean Mixing

    NASA Astrophysics Data System (ADS)

    Ferrari, R. M.; Nikurashin, M.; McDougall, T. J.; Mashayek, A.

    2014-12-01

    The upwelling of bottom waters through density surfaces in the deep ocean is not possible unless the sloping nature of the sea floor is taken into account. The bottom--intensified mixing arising from interaction of internal tides and geostrophic motions with bottom topography implies that mixing is a decreasing function of height in the deep ocean. This would further imply that the diapycnal motion in the deep ocean is downward, not upwards as is required by continuity. This conundrum regarding ocean mixing and upwelling in the deep ocean will be resolved by appealing to the fact that the ocean does not have vertical side walls. Implications of the conundrum for the representation of ocean mixing in climate models will be discussed.

  17. Beam Profile Monitor With Accurate Horizontal And Vertical Beam Profiles

    DOEpatents

    Havener, Charles C [Knoxville, TN; Al-Rejoub, Riad [Oak Ridge, TN

    2005-12-26

    A widely used scanner device that rotates a single helically shaped wire probe in and out of a particle beam at different beamline positions to give a pair of mutually perpendicular beam profiles is modified by the addition of a second wire probe. As a result, a pair of mutually perpendicular beam profiles is obtained at a first beamline position, and a second pair of mutually perpendicular beam profiles is obtained at a second beamline position. The simple modification not only provides more accurate beam profiles, but also provides a measurement of the beam divergence and quality in a single compact device.

  18. Vertical velocity in cirrus case obtained from wind profiler

    NASA Technical Reports Server (NTRS)

    Song, Ran; Cox, Stephen K.

    1993-01-01

    Cirrus clouds play an important role in the climate and general circulation because they significantly modulate the radiation properties of the atmosphere. However understanding the processes that govern their presence is made difficult by their high altitude, variable thickness, complex microphysical structure, and relatively little knowledge of the vertical motion field. In the FIRE 2 (First International Satellite Cloud Climatology Regional Experiment) experiment, a 404 MHz wind profiler was set up to provide continuous measurements of clear air wind field at Parsons, Kansas. Simultaneously, the NOAA wind profiler network supplied a wider spacial scale observation. On 26 Nov. 1991, the most significant cirrus cloud phenomena during the experiment with a jet streak at 250 Mb occurred. Analyses of the vertical wind velocity are made by utilizing different methods based on wind profiler data, among them the direct measurements from CSU wind profiler and NOAA network wind profilers, VAD (Velocity Azimuth Display) technique and the kinematic method.

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

    NASA Astrophysics Data System (ADS)

    Kräuchi, Andreas; Philipona, Rolf

    2014-05-01

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

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

    EPA Science Inventory

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

  1. Flight dynamics of a pterosaur-inspired aircraft utilizing a variable-placement vertical tail.

    PubMed

    Roberts, Brian; Lind, Rick; Chatterjee, Sankar

    2011-06-01

    Mission performance for small aircraft is often dependent on the turn radius. Various biologically inspired concepts have demonstrated that performance can be improved by morphing the wings in a manner similar to birds and bats; however, the morphing of the vertical tail has received less attention since neither birds nor bats have an appreciable vertical tail. This paper investigates a design that incorporates the morphing of the vertical tail based on the cranial crest of a pterosaur. The aerodynamics demonstrate a reduction in the turn radius of 14% when placing the tail over the nose in comparison to a traditional aft-placed vertical tail. The flight dynamics associated with this configuration has unique characteristics such as a Dutch-roll mode with excessive roll motion and a skid divergence that replaces the roll convergence.

  2. Flight dynamics of a pterosaur-inspired aircraft utilizing a variable-placement vertical tail.

    PubMed

    Roberts, Brian; Lind, Rick; Chatterjee, Sankar

    2011-06-01

    Mission performance for small aircraft is often dependent on the turn radius. Various biologically inspired concepts have demonstrated that performance can be improved by morphing the wings in a manner similar to birds and bats; however, the morphing of the vertical tail has received less attention since neither birds nor bats have an appreciable vertical tail. This paper investigates a design that incorporates the morphing of the vertical tail based on the cranial crest of a pterosaur. The aerodynamics demonstrate a reduction in the turn radius of 14% when placing the tail over the nose in comparison to a traditional aft-placed vertical tail. The flight dynamics associated with this configuration has unique characteristics such as a Dutch-roll mode with excessive roll motion and a skid divergence that replaces the roll convergence. PMID:21558603

  3. Vertical Profiles as Observational Constraints on Nitrous Oxide (N2O) Emissions in an Agricultural Region

    NASA Astrophysics Data System (ADS)

    Pusede, S.; Diskin, G. S.

    2015-12-01

    We use diurnal variability in near-surface N2O vertical profiles to derive N2O emission rates. Our emissions estimates are ~3 times greater than are accounted for by inventories, a discrepancy in line with results from previous studies using different approaches. We quantify the surface N2O concentration's memory of local surface emissions on previous days to be 50-90%. We compare measured profiles both over and away from a dense N2O source region in the San Joaquin Valley, finding that profile shapes, diurnal variability, and changes in integrated near-surface column abundances are distinct according to proximity to source areas. To do this work, we use aircraft observations from the wintertime DISCOVER-AQ project in California's San Joaquin Valley, a region of intense agricultural activity.

  4. Concentric circles based simple optical landing aid for vertical takeoff and landing aircrafts

    NASA Astrophysics Data System (ADS)

    Murshid, Syed H.; Enaya, Rayan; Lovell, Gregory L.

    2014-09-01

    Vertical takeoff and landing (VTOL) aircrafts such as helicopters and drones, add a flexible degree of operation to airborne vehicles. In order to operate these devices in low light situations, where it is difficult to determine slope of the landing surface, a lightweight and standalone device is proposed here. This small optical device can be easily integrated into current VTOL systems. An optical projector consisting of low power, light weight, solid state laser along with minimal optics is utilized to illuminate the landing surface with donut shaped circles and coaxial centralized dot. This device can placed anywhere on the aircraft and a properly placed fiber system can be used to illuminate the surface beneath the bottom of the VTOL aircraft in a fashion that during operation, when the aircraft is parallel to the landing surface, the radius between the central dot and outer ring(s) are equidistant for the entire circumference; however, when there the landing surface of the VTOL aircraft is not parallel to the landing strip, the radial distance between two opposite sides of the circle and central dot will be unequal. The larger this distortion, the greater the difference will be between the opposite sides of the circle. Visual confirmation or other optical devices can be used to determine relative alignment of the projector output allowing the pilot to make proper adjustments as they approach the landing surface to ensure safe landings. Simulated and experimental results from a prototype optical projector are presented here.

  5. Vertical profiles of cloud condensation nuclei, aerosol hygroscopicity, water uptake, and scattering across the United States

    NASA Astrophysics Data System (ADS)

    Lin, J. J.; Bougiatioti, A.; Nenes, A.; Anderson, B. E.; Beyersdorf, A. J.; Brock, C. A.; Gordon, T. D.; Lack, D.; Law, D. C.; Liao, J.; Middlebrook, A. M.; Richardson, M.; Thornhill, K. L., II; Winstead, E.; Wagner, N. L.; Welti, A.; Ziemba, L. D.

    2014-12-01

    The evolutions of vertical distributions of aerosol chemical, microphysical, hygroscopic, and optical properties present fundamental challenges to the understanding of ground-level air quality and radiative transfer, and few datasets exist to date for evaluation of atmospheric models. Data collected from recent NASA and NOAA field campaigns in the California Central Valley (DISCOVER-AQ), southeast United States (SENEX, SEAC4RS) and Texas (DISCOVER-AQ) allow for a unique opportunity to constrain vertical profiles of climate-relevant aerosol properties. This work presents in-situ aircraft measurements of cloud condensation nuclei (CCN) concentration and derivations of aerosol hygroscopicity, water uptake, and light scattering. Aerosol hygroscopicity is derived from CCN and aerosol measurements. Inorganic water uptake is calculated from aerosol composition using ISORROPIA, a chemical thermodynamic model, while organic water uptake is calculated from organic hygroscopicity. Aerosol scattering closure is performed between scattering from water uptake calculations and in-situ scattering measurements.

  6. An experimental study of concurrent methods for adaptively controlling vertical tail buffet in high performance aircraft

    NASA Astrophysics Data System (ADS)

    Roberts, Patrick J.

    High performance twin-tail aircraft, like the F-15 and F/A-18, encounter a condition known as tail buffet. At high angles of attack, vortices are generated at the wing fuselage interface (shoulder) or other leading edge extensions. These vortices are directed toward the twin vertical tails. When the flow interacts with the vertical tail it creates pressure variations that can oscillate the vertical tail assembly. This results in fatigue cracks in the vertical tail assembly that can decrease the fatigue life and increase maintenance costs. Recently, an offset piezoceramic stack actuator was used on an F-15 wind tunnel model to control buffet induced vibrations at high angles of attack. The controller was based on the acceleration feedback control methods, In this thesis a procedure for designing the offset piezoceramic stack actuators is developed. This design procedure includes determining the quantity and type of piezoceramic stacks used in these actuators. The changes of stresses, in the vertical tail caused by these actuators during an active control, are investigated. In many cases, linear controllers are very effective in reducing vibrations. However, during flight, the natural frequencies of the vertical tail structural system changes as the airspeed increases. This in turn, reduces the effectiveness of a linear controller. Other causes such as the unmodeled dynamics and nonlinear effects due to debonds also reduce the effectiveness of linear controllers. In this thesis, an adaptive neural network is used to augment the linear controller to correct these effects.

  7. Apparent abundance and vertical profiles of ozone from OMEGA measurements

    NASA Astrophysics Data System (ADS)

    Altieri, F.; Zasova, L.; Grassi, D.; Bellucci, G.; Bibring, J.-P.; Formisano, V.; Ignatiev, N.; Drossart, P.; Encrenaz, T.; Fouchet, T.; OMEGA Team

    In this work we study the vertical and seasonal distribution of O2 by means the 1.27 micron day glow emission in the spectra acquired by OMEGA, the imaging spectrometer on board the ESA mission Mars Express. Limb OMEGA observations have been used to retrieve the vertical distribution of O3 up to 20 km, applying an "onion peeling" procedure. The quenching effect due to the collisions with the CO2 have been taken into account using simultaneously vertical CO2 profiles obtained by the PFS LWC data. OMEGA nadir observations have been used to map the latitude, local time and seasonal distribution of the apparent ozone abundance in the Martian atmosphere and results are discussed. We acknowledge the ESA Headquarters and IFSI-INAF for support to Russian CoIs and the Russian Foundation of Basic Research for grant RFFI 04-02-16856a.

  8. Seasonal variation of vertical distribution of aerosol single scattering albedo over Indian sub-continent: RAWEX aircraft observations

    NASA Astrophysics Data System (ADS)

    Suresh Babu, S.; Nair, Vijayakumar S.; Gogoi, Mukunda M.; Krishna Moorthy, K.

    2016-01-01

    To characterize the vertical distribution of aerosols and its seasonality (especially the single scattering albedo, SSA) extensive profiling of aerosol scattering and absorption coefficients have been carried out using an instrumented aircraft from seven base stations spread across the Indian mainland during winter 2012 and spring/pre-monsoon 2013 under the Regional Aerosol Warming Experiment (RAWEX). Spatial variation of the vertical profiles of the asymmetry parameter, the wavelength exponent of the absorption coefficient and the single scattering albedo, derived from the measurements, are used to infer the source characteristics of winter and pre-monsoon aerosols as well as the seasonality of free tropospheric aerosols. The relatively high value of the wavelength exponent of absorption coefficient over most of the regions indicates the contribution from biomass burning and dust aerosols up to lower free tropospheric altitudes. A clear enhancement in aerosol loading and its absorbing nature is seen at lower free troposphere levels (above the planetary boundary layer) over the entire mainland during spring/pre-monsoon season compared to winter, whereas concentration of aerosols within the boundary layer showed a decrease from winter to spring. This could have significant implications on the aerosol heating structure over the Indian region and hence the regional climate.

  9. A mathematical model for Vertical Attitude Takeoff and Landing (VATOL) aircraft simulation. Volume 3: User's manual for VATOL simulation program

    NASA Technical Reports Server (NTRS)

    Fortenbaugh, R. L.

    1980-01-01

    Instructions for using Vertical Attitude Takeoff and Landing Aircraft Simulation (VATLAS), the digital simulation program for application to vertical attitude takeoff and landing (VATOL) aircraft developed for installation on the NASA Ames CDC 7600 computer system are described. The framework for VATLAS is the Off-Line Simulation (OLSIM) routine. The OLSIM routine provides a flexible framework and standardized modules which facilitate the development of off-line aircraft simulations. OLSIM runs under the control of VTOLTH, the main program, which calls the proper modules for executing user specified options. These options include trim, stability derivative calculation, time history generation, and various input-output options.

  10. Crash Simulation of a Vertical Drop Test of a Commuter-Class Aircraft

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Fasanella, Edwin L.

    2004-01-01

    A finite element model of an ATR42-300 commuter-class aircraft was developed and a crash simulation was executed. Analytical predictions were correlated with data obtained from a 30-ft/s (9.14-m/s) vertical drop test of the aircraft. The purpose of the test was to evaluate the structural response of the aircraft when subjected to a severe, but survivable, impact. The aircraft was configured with seats, dummies, luggage, and other ballast. The wings were filled with 8,700 lb. (3,946 kg) of water to represent the fuel. The finite element model, which consisted of 57,643 nodes and 62,979 elements, was developed from direct measurements of the airframe geometry. The seats, dummies, luggage, fuel, and other ballast were represented using concentrated masses. The model was executed in LS-DYNA, a commercial code for performing explicit transient dynamic simulations. Predictions of structural deformation and selected time-history responses were generated. The simulation was successfully validated through extensive test-analysis correlation.

  11. Surface tension profiles in vertical soap films: an intrusive measurement

    NASA Astrophysics Data System (ADS)

    Adami, Nicolas; Dorbolo, Stéphane; Caps, Hervé; Grasp Team

    2012-11-01

    Soap films are known to be the basic constituent of complex fluid objects such as bubbles and foams. In order for their weight to be counterbalanced, those objects need to exhibit vertical surface tension profiles, which can only exist due to the presence of surfactant molecules at their interfaces. We here present a method that aims to probe vertical soap films surface tension profiles by use of elasto-capillary deformations. Both cases of free-draining and entertained soap films are investigated, leading the spatio-temporal behavior of the surface tension. We show that this behavior is highly dependent on the nature of the surfactant used to create soap films, emphasizing the influence of the physico-chemistry on the global behavior of the system. We propose order of magnitude calculations, which are in good agreement with experimental data.

  12. Black Carbon Vertical Profiles Strongly Affect Its Radiative Forcing Uncertainty

    NASA Technical Reports Server (NTRS)

    Samset, B. H.; Myhre, G.; Schulz, M.; Balkanski, Y.; Bauer, S.; Berntsen, T. K.; Bian, H.; Bellouin, N.; Diehl, T.; Easter, R. C.; Ghan, S. J.; Iversen, T.; Kinne, S.; Kirkevag, A.; Lamarque, J.-F.; Lin, G.; Liu, X.; Penner, J. E.; Seland, O.; Skeie, R. B.; Stier, P.; Takemura, T.; Tsigaridis, K.; Zhang, K.

    2013-01-01

    The impact of black carbon (BC) aerosols on the global radiation balance is not well constrained. Here twelve global aerosol models are used to show that at least 20% of the present uncertainty in modeled BC direct radiative forcing (RF) is due to diversity in the simulated vertical profile of BC mass. Results are from phases 1 and 2 of the global aerosol model intercomparison project (AeroCom). Additionally, a significant fraction of the variability is shown to come from high altitudes, as, globally, more than 40% of the total BC RF is exerted above 5 km. BC emission regions and areas with transported BC are found to have differing characteristics. These insights into the importance of the vertical profile of BC lead us to suggest that observational studies are needed to better characterize the global distribution of BC, including in the upper troposphere.

  13. Black Carbon Vertical Profiles Strongly Affect its Radiative Forcing Uncertainty

    SciTech Connect

    Samset, B. H.; Myhre, G.; Schulz, M.; Balkanski, Y.; Bauer, Susanne E.; Berntsen, T.; Bian, Huisheng; Bellouin, N.; Diehl, T.; Easter, Richard C.; Ghan, Steven J.; Iversen, T.; Kinne, Stefan; Kirkevag, A.; Lamarque, J.-F.; Lin, G.; Liu, Xiaohong; Penner, Joyce E.; Seland, O.; Skeie, R. B.; Stier, P.; Takemura, T.; Tsigaridis, K.; Zhang, Kai

    2013-03-01

    The impact of black carbon (BC) aerosols on the global radiation balance is not well constrained. Here twelve global aerosol models are used to show that at least 20% of the present uncertainty in modeled BC direct radiative forcing (RF) is due to diversity in the simulated vertical profile of BC mass. Results are from phases 1 and 2 of the global aerosol model intercomparison project (AeroCom). Additionally, a significant fraction of the variability is shown to come from high altitudes, as, globally, more than 40% of the total BC RF is exerted above 5 km. BC emission regions and areas with transported BC are found to have differing characteristics. These insights into the importance of the vertical profile of BC lead us to suggest that observational studies are needed to better characterize the global distribution of BC, including in the upper troposphere.

  14. Vertical soil profiling using a galvanic contact resistivity scanning approach.

    PubMed

    Pan, Luan; Adamchuk, Viacheslav I; Prasher, Shiv; Gebbers, Robin; Taylor, Richard S; Dabas, Michel

    2014-07-23

    Proximal sensing of soil electromagnetic properties is widely used to map spatial land heterogeneity. The mapping instruments use galvanic contact, capacitive coupling or electromagnetic induction. Regardless of the type of instrument, the geometrical configuration between signal transmitting and receiving elements typically defines the shape of the depth response function. To assess vertical soil profiles, many modern instruments use multiple transmitter-receiver pairs. Alternatively, vertical electrical sounding can be used to measure changes in apparent soil electrical conductivity with depth at a specific location. This paper examines the possibility for the assessment of soil profiles using a dynamic surface galvanic contact resistivity scanning approach, with transmitting and receiving electrodes configured in an equatorial dipole-dipole array. An automated scanner system was developed and tested in agricultural fields with different soil profiles. While operating in the field, the distance between current injecting and measuring pairs of rolling electrodes was varied continuously from 40 to 190 cm. The preliminary evaluation included a comparison of scan results from 20 locations to shallow (less than 1.2 m deep) soil profiles and to a two-layer soil profile model defined using an electromagnetic induction instrument.

  15. Vertical soil profiling using a galvanic contact resistivity scanning approach.

    PubMed

    Pan, Luan; Adamchuk, Viacheslav I; Prasher, Shiv; Gebbers, Robin; Taylor, Richard S; Dabas, Michel

    2014-01-01

    Proximal sensing of soil electromagnetic properties is widely used to map spatial land heterogeneity. The mapping instruments use galvanic contact, capacitive coupling or electromagnetic induction. Regardless of the type of instrument, the geometrical configuration between signal transmitting and receiving elements typically defines the shape of the depth response function. To assess vertical soil profiles, many modern instruments use multiple transmitter-receiver pairs. Alternatively, vertical electrical sounding can be used to measure changes in apparent soil electrical conductivity with depth at a specific location. This paper examines the possibility for the assessment of soil profiles using a dynamic surface galvanic contact resistivity scanning approach, with transmitting and receiving electrodes configured in an equatorial dipole-dipole array. An automated scanner system was developed and tested in agricultural fields with different soil profiles. While operating in the field, the distance between current injecting and measuring pairs of rolling electrodes was varied continuously from 40 to 190 cm. The preliminary evaluation included a comparison of scan results from 20 locations to shallow (less than 1.2 m deep) soil profiles and to a two-layer soil profile model defined using an electromagnetic induction instrument. PMID:25057135

  16. Vertical Soil Profiling Using a Galvanic Contact Resistivity Scanning Approach

    PubMed Central

    Pan, Luan; Adamchuk, Viacheslav I.; Prasher, Shiv; Gebbers, Robin; Taylor, Richard S.; Dabas, Michel

    2014-01-01

    Proximal sensing of soil electromagnetic properties is widely used to map spatial land heterogeneity. The mapping instruments use galvanic contact, capacitive coupling or electromagnetic induction. Regardless of the type of instrument, the geometrical configuration between signal transmitting and receiving elements typically defines the shape of the depth response function. To assess vertical soil profiles, many modern instruments use multiple transmitter-receiver pairs. Alternatively, vertical electrical sounding can be used to measure changes in apparent soil electrical conductivity with depth at a specific location. This paper examines the possibility for the assessment of soil profiles using a dynamic surface galvanic contact resistivity scanning approach, with transmitting and receiving electrodes configured in an equatorial dipole-dipole array. An automated scanner system was developed and tested in agricultural fields with different soil profiles. While operating in the field, the distance between current injecting and measuring pairs of rolling electrodes was varied continuously from 40 to 190 cm. The preliminary evaluation included a comparison of scan results from 20 locations to shallow (less than 1.2 m deep) soil profiles and to a two-layer soil profile model defined using an electromagnetic induction instrument. PMID:25057135

  17. Vertical profile of atmospheric conductivity that matches Schumann resonance observations.

    PubMed

    Nickolaenko, Alexander P; Galuk, Yuri P; Hayakawa, Masashi

    2016-01-01

    We introduce the vertical profile of atmospheric conductivity in the range from 2 to 98 km. The propagation constant of extremely low frequency (ELF) radio waves was computed for this profile by using the full wave solution. A high correspondence is demonstrated of the data thus obtained to the conventional standard heuristic model of ELF propagation constant derived from the Schumann resonance records performed all over the world. We also suggest the conductivity profiles for the ambient day and ambient night conditions. The full wave solution technique was applied for obtaining the corresponding frequency dependence of propagation constant relevant to these profiles. By using these propagation constants, we computed the power spectra of Schumann resonance in the vertical electric field component for the uniform global distribution of thunderstorms and demonstrate their close similarity in all the models. We also demonstrate a strong correspondence between the wave attenuation rate obtained for these conductivity profiles and the measured ones by using the ELF radio transmissions. PMID:26877906

  18. Subsonic Aircraft Soot: A Tracer Documenting Stratospheric Vertical Mixing and Barriers to Inter-Hemispheric Exchanges

    NASA Technical Reports Server (NTRS)

    Pueschel, Rudolf F.; Gore, Warren J. (Technical Monitor)

    1996-01-01

    Pole-to-pole variability of soot aerosol from subsonic aircraft is evidence of two important aspects of stratospheric transport. Vertical transport to 20 km pressure altitude from flight levels near 10-12 km cannot be explained by isentropic mixing. Instead, lofting in the tropics is a possibility. A strong meridional gradient implies that stratospheric soot aerosol residence time is shorter than are mixing times between the hemispheres. Therefore, little if any of exhaust constituents (with residence times similar to that of aircraft soot aerosol), emitted in heavily traveled flight corridors in northern mid-latitudes by a future supersonic fleet, would be transported to the southern hemisphere. However, a significant fraction of NOx could be lofted to altitudes above flight levels where it would dominate ozone depletion.

  19. TOMS Validation Based on Profiles of Aerosol Properties in the Lower Troposphere as Obtained with Light Aircraft Systems

    NASA Technical Reports Server (NTRS)

    Prospero, Joseph M.; Maring, Hal; Savoie, Dennis

    2003-01-01

    The goal of the University of Miami Aerosol Group (UMAG) in this project was to make measurements of vertical profiles of aerosol properties and aerosol optical depth using a light aircraft. The UMAG developed a light aircraft aerosol package (LAAP) that was used in light aircraft (Cessna 172) during the Puerto Rico Dust Experiment (PRIDE). This field campaign took place on Puerto Rico during July 2000. Design details and results from the use of the LAAP were presented at TOMS Science team meetings on April 1998, April 1999, and May 2000. Results from the LAAP collected during the PRIDE Experiment were presented at the Fall Meeting of the American Geophysical Union, December 2000. Some of the results from the LAAP collected during the PRIDE Experiment have been accepted for publication in the Journal of Geophysical Research in a "topical section" made up of papers from the PRIDE Program.

  20. Vertical profiles of BC direct radiative effect over Italy: high vertical resolution data and atmospheric feedbacks

    NASA Astrophysics Data System (ADS)

    Močnik, Griša; Ferrero, Luca; Castelli, Mariapina; Ferrini, Barbara S.; Moscatelli, Marco; Grazia Perrone, Maria; Sangiorgi, Giorgia; Rovelli, Grazia; D'Angelo, Luca; Moroni, Beatrice; Scardazza, Francesco; Bolzacchini, Ezio; Petitta, Marcello; Cappelletti, David

    2016-04-01

    Black carbon (BC), and its vertical distribution, affects the climate. Global measurements of BC vertical profiles are lacking to support climate change research. To fill this gap, a campaign was conducted over three Italian basin valleys, Terni Valley (Appennines), Po Valley and Passiria Valley (Alps), to characterize the impact of BC on the radiative budget under similar orographic conditions. 120 vertical profiles were measured in winter 2010. The BC vertical profiles, together with aerosol size distribution, aerosol chemistry and meteorological parameters, have been determined using a tethered balloon-based platform equipped with: a micro-Aethalometer AE51 (Magee Scientific), a 1.107 Grimm OPC (0.25-32 μm, 31 size classes), a cascade impactor (Siuotas SKC), and a meteorological station (LSI-Lastem). The aerosol chemical composition was determined from collected PM2.5 samples. The aerosol absorption along the vertical profiles was measured and optical properties calculated using the Mie theory applied to the aerosol size distribution. The aerosol optical properties were validated with AERONET data and then used as inputs to the radiative transfer model libRadtran. Vertical profiles of the aerosol direct radiative effect, the related atmospheric absorption and the heating rate were calculated. Vertical profile measurements revealed some common behaviors over the studied basin valleys. From below the mixing height to above it, a marked concentration drop was found for both BC (from -48.4±5.3% up to -69.1±5.5%) and aerosol number concentration (from -23.9±4.3% up to -46.5±7.3%). These features reflected on the optical properties of the aerosol. Absorption and scattering coefficients decreased from below the MH to above it (babs from -47.6±2.5% up to -71.3±3.0% and bsca from -23.5±0.8% up to -61.2±3.1%, respectively). Consequently, the Single Scattering Albedo increased above the MH (from +4.9±2.2% to +7.4±1.0%). The highest aerosol absorption was

  1. Design of a Low Cost Short Takeoff-vertical Landing Export Fighter/attack Aircraft

    NASA Technical Reports Server (NTRS)

    Belcher, Anne; Bodeker, Dan, III; Miu, Steve; Petro, Laura; Senf, Cary Taylor; Woeltjen, Donald

    1990-01-01

    The design of a supersonic short takeoff and vertical landing (STOVL) aircraft is presented that is suitable for export. An advanced four poster, low bypass turbofan engine is to be used for propulsion. Preliminary aerodynamic analysis is presented covering a determination of CD versus CL, CD versus Mach number, as well as best cruise Mach number and altitude. Component locations are presented and center of gravity determined. Cost minimization is achieved through the use of developed subsystems and standard fabrication techniques using nonexotic materials. Conclusions regarding the viability of the STOVL design are presented.

  2. Vertical NO2 Profile measurements in Hong Kong using DOAS

    NASA Astrophysics Data System (ADS)

    Wenig, Mark; Bräu, Melanie; Zhu, Ying; Lipkowitsch, Ivo; Röttger, Clemens; Fat Lam, Yun

    2016-04-01

    In this presentation we describe our first measurements of vertical NO2 distributions in a street canyon in Hong Kong using different DOAS techniques. One approach is to use mobile cavity-enhanced DOAS (CE-DOAS) measurements on different floors of a high rise building to assemble a profile. In addition to this we use a ToTaL-DOAS (Topographic Target Light Scattering DOAS) approach to measure vertical and horizontal distributions of NO2 SCDs of the Hong Kong skyline including the building we used for the CE-DOAS measurements. As a third option to generate profile information, we use data from the Hong Kong Environmental Protection department (EPD) measurement stations. Each measurement location is at a different height and we used a concentration map we assembled using mobile CE-DOAS measurements which again had been corrected for diurnal variations using a continuously measuring LP-DOAS for horizontal extrapolation. We compare parameterized profiles from those three different methods and discuss how profile information can be used to make urban air quality monitoring more comparable.

  3. Comparison of MADE3-simulated and observed aerosol distributions with a focus on aerosol vertical profiles

    NASA Astrophysics Data System (ADS)

    Kaiser, Christopher; Hendricks, Johannes; Righi, Mattia; Jöckel, Patrick

    2016-04-01

    aerosol and black carbon mass mixing ratio with altitude than found in the observations. In contrast, measured profiles from the HIPPO project are qualitatively captured well. Similar conclusions hold for the comparison of simulated and measured aerosol particle number concentrations. On the one hand, these results exemplify the difficulty in evaluating the representativeness of the simulated global climatological state of the aerosol by means of comparison with individually measured vertical profiles. On the other hand, it highlights the value of aircraft campaigns with large spatial and temporal coverage for model evaluation.

  4. Depth profiles and free volume in aircraft primer films

    NASA Astrophysics Data System (ADS)

    Van Horn, J. D.; Chen, H.; Jean, Y. C.; Zhang, W.; Jaworowski, M. R.

    2015-06-01

    Positron annihilation lifetime spectroscopy (PALS) and associated techniques provide non-destructive methods to study the free volume inside polymeric materials, and to study material characteristics over a depth profile. Cast free films of organic- or aqueous-based, non-chromated aerospace primers, when cured for about one week, had very different water vapour transport (through-plane) behaviour. In addition, both types of primer films showed strong anisotropic behaviour in in-plane versus through-plane water vapour transport rates. We report the differences between the organic- and aqueous-based aircraft primer films samples and their surface depth profiles. In bulk PALS measurements, an aged, organic-based film exhibited typical lifetimes and intensities for a particulate-containing polymer film on both faces. In contrast, aqueous-based films exhibited face oriented-dependent differences. In all aqueous- based samples, the I3 value of the back of the sample was smaller. The primer film samples were also evaluated with mono-energetic positron beam techniques to generate depth profile information. The heterogeneity in the samples was verified by Doppler broadening of energy spectroscopy (DBES). A model for the differences in the faces of the films, and their layered structure is discussed.

  5. Measuring Vertical Profiles of Wind, Temperature and Humidity within the Atmospheric Boundary Layer using the Research UAVs 'M2AV Carolo'

    NASA Astrophysics Data System (ADS)

    Bange, J.; Martin, S.

    2009-09-01

    The measurement of vertical profiles is important to characterise the vertical structure of the atmospheric boundary layer (ABL). For instance, the dependence of the potential temperature on altitude defines the thermal stratification. The mechanical shear (i.e. the variation of wind speed and direction) produces turbulence and turbulent fluxes. The top of the ABL is required for scaling approaches (e.g. Deardorff scaling in the convective boundary layer, local scaling in the stable boundary layer). The Meteorological Mini Aerial Vehicles (M²AV) are self-constructed, automatically operating research aircraft of 6 kg in weight (including 1.5 kg scientific payload) and 2 m wingspan. These systems are capable of performing turbulence measurements (wind vector, temperature and humidity) and are used as a new instrument for measuring vertical profiles of the lower troposphere. Compared to a radiosonde, the spatial resolution of the M²AV is significantly higher. Especially the wind measurement is significantly more accurate compared to radiosonde data when using an aircraft that is equipped with a proper flow sensor (mainly a five-hole probe). It is important to maintain flow angles (sideslip and angle of attack) within the calibration range (typically 10 to 20 degree). This limits the vertical speed (the rate of climb and descent) of the research aircraft. In general there are two approaches to measure vertical profiles with research aircraft. Instantaneous profiles (slant flight pattern) are suitable if only little time is available, if the ABL is very in-stationary (or the aircraft is slow), if the dependence of the profile on time is requested (repeated slant flight patterns over one location) or if the dependence of the profile on the location is requested (saw-tooth pattern). For mean profiles (horizontal straight and level flights 'legs' at several altitudes within the ABL) it is necessary to use fast sensors. If the response time is too large, the vertical

  6. Sampling the Vertical Moisture Structure of an Atmospheric River Event Using Airborne GPS Radio Occultation Profiling

    NASA Astrophysics Data System (ADS)

    Haase, J. S.; Malloy, K.; Murphy, B.; Sussman, J.; Zhang, W.

    2015-12-01

    Atmospheric rivers (ARs) are of high concern in California, bringing significant rain to the region over extended time periods of up to 5 days, potentially causing floods, and more importantly, contributing to the Sierra snowpack that provides much of the regional water resources. The CalWater project focuses on predicting the variability of the West Coast water supply, including improving AR forecasting. Unfortunately, data collection over the ocean remains a challenge and impacts forecasting accuracy. One novel technique to address this issue includes airborne GPS radio occultation (ARO), using broadcast GPS signals from space to measure the signal ray path bending angle and refractivity to retrieve vertical water vapor profiles. The Global Navigation Satellite System Instrument System for Multistatic and Occultation Sensing (GISMOS) system was developed for this purpose for recording and processing high-sample rate (10MHz) signals in the lower troposphere. Previous studies (Murphy et al, 2014) have shown promising results in acquiring airborne GPS RO data, comparing it to dropsondes and numerical weather models. CalWater launched a field campaign in the beginning of 2015 which included testing GISMOS ARO on the NOAA GIV aircraft for AR data acquisition, flying into the February 6th AR event that brought up to 35 cm of rain to central California. This case study will compare airborne GPS RO refractivity profiles to the NCEP-NCAR final reanalysis model and dropsonde profiles. We will show the data distribution and explain the sampling characteristics, providing high resolution vertical information to the sides of the aircraft in a manner complementary to dropsondes beneath the flight track. We will show how this method can provide additional reliable data during the development of AR storms.

  7. Radial-vertical profiles of tropical cyclone derived from dropsondes

    NASA Astrophysics Data System (ADS)

    Ren, Yifang

    The scopes of this thesis research are two folds: the first one is to the construct the intensity-based composite radial-vertical profiles of tropical cyclones (TC) using GPS-based dropsonde observations and the second one is to identify the major deficiencies of Mathur vortices against the dropsonde composites of TCs. The intensity-based dropsonde composites of TCs advances our understanding of the dynamic and thermal structure of TCs of different intensity along the radial direction in and above the boundary layer where lies the devastating high wind that causes property damages and storm surges. The identification of the major deficiencies of Mathur vortices in representing the radial-vertical profiles of TC of different intensity helps to improve numerical predictions of TCs since most operational TC forecast models need to utilize bogus vortices, such as Mathur vortices, to initialize TC forecasts and simulations. We first screen all available GPS dropsonde data within and round 35 named TCs over the tropical Atlantic basin from 1996 to 2010 and pair them with TC parameters derived from the best-track data provided by the National Hurricane Center (NHC) and select 1149 dropsondes that have continuous coverage in the lower troposphere. The composite radial-vertical profiles of tangential wind speed, temperature, mixing ratio and humidity are based for each TC category ranging from "Tropical Storm" (TS) to "Hurricane Category 1" (H1) through "Hurricane Category 5" (H5). The key findings of the dropsonde composites are: (i) all TCs have the maximum tangential wind within 1 km above the ground and a distance of 1-2 times of the radius of maximum wind (RMW) at the surface; (ii) all TCs have a cold ring surrounding the warm core near the boundary layer at a distance of 1-3 times of the RMW and the cold ring structure gradually diminishes at a higher elevation where the warm core structure prevails along the radial direction; (iii) the existence of such shallow cold

  8. Retrieving Latent Heat Vertical Structure Using Precipitation and Cloud Profiles

    NASA Astrophysics Data System (ADS)

    Li, R.; Min, Q.; Wu, X.

    2011-12-01

    The latent heat (LH) released from tropical precipitation plays a critical role in driving regional and global atmosphere circulation. However, the vertical distribution of LH is one of most difficult parameters to be measured and has a large uncertainty in both residual diagnostic products and satellite retrievals. Most of current satellite LH products use limited observational information of precipitation and cloud profiles and highly depend on cloud resolving model (CRM) simulations. Our novel approach, distinguishing from existing schemes, is directly using observable precipitation and cloud profiles in combination with phase change partition parameterization of various kinds from the CRM simulations to produce the latent heating profiles. This hybrid latent heat algorithm separately deals with the condensation-evaporation heating (LHc_e), the deposition-sublimation heating (LHd_s) and the freezing-melting heating (LHf_m) for convective rain, stratiform rain, and shallow warm rain. Each component is based on physical processes, such as nucleation and auto conversion, by combining observable precipitation and cloud profiles. Although the proposed algorithm utilizes microphysical parameterizations from a specific CRM, the general LH vertical structure is primarily determined by the precipitation and cloud profiles observable from cloud and precipitation radars available at ground sites or from satellite platforms, and less sensitive to the specific CRM. The self consistency tests of this algorithm show good agreements with the CRM simulated LH at different spatial and temporal scales, even at simultaneous and pixel level. The applications of this algorithm are expected to provide new information for understanding the heating budget in the atmosphere and its impacts on the atmosphere circulations at various spatial and temporal scales.

  9. Normalized vertical ice mass flux profiles from vertically pointing 8-mm-wavelength Doppler radar

    NASA Technical Reports Server (NTRS)

    Orr, Brad W.; Kropfli, Robert A.

    1993-01-01

    During the FIRE 2 (First International Satellite Cloud Climatology Project Regional Experiment) project, NOAA's Wave Propagation Laboratory (WPL) operated its 8-mm wavelength Doppler radar extensively in the vertically pointing mode. This allowed for the calculation of a number of important cirrus cloud parameters, including cloud boundary statistics, cloud particle characteristic sizes and concentrations, and ice mass content (imc). The flux of imc, or, alternatively, ice mass flux (imf), is also an important parameter of a cirrus cloud system. Ice mass flux is important in the vertical redistribution of water substance and thus, in part, determines the cloud evolution. It is important for the development of cloud parameterizations to be able to define the essential physical characteristics of large populations of clouds in the simplest possible way. One method would be to normalize profiles of observed cloud properties, such as those mentioned above, in ways similar to those used in the convective boundary layer. The height then scales from 0.0 at cloud base to 1.0 at cloud top, and the measured cloud parameter scales by its maximum value so that all normalized profiles have 1.0 as their maximum value. The goal is that there will be a 'universal' shape to profiles of the normalized data. This idea was applied to estimates of imf calculated from data obtained by the WPL cloud radar during FIRE II. Other quantities such as median particle diameter, concentration, and ice mass content can also be estimated with this radar, and we expect to also examine normalized profiles of these quantities in time for the 1993 FIRE II meeting.

  10. Vertical profile of fog microphysics : a case study

    NASA Astrophysics Data System (ADS)

    Burnet, Frédéric; Brilouet, Pierre-Etienne; Mazoyer, Marie; Bourrianne, Thierry; Etcheberry, Jean-Michel; Gaillard, Brigitte; Legain, Dominique; Tzanos, Diane; Barrié, Joel; Barrau, Sébastien; Defoy, Stephan

    2016-04-01

    The occurrence and development of fogs result from the non-linear interaction of competing radiative, thermodynamic, microphysical and dynamical processes and the forecasting of their life cycle still remains a challenging issue. Several field campaigns have been carried out at the SIRTA observatory in the Paris suburb area (France). These experiments have shown that fog events exhibit large differences of the microphysical properties and various evolutions during their life cycle. To better understand relationships between the different processes and to validate numerical simulations it is necessary however to document the vertical profile of the fog microphysics. A CDP (Cloud Droplet Spectrometer) from DMT (Droplet Measurement Technology, Boulder, CO) has been modified to allow measurements of the droplet size distribution in fog layers with a tethered balloon. This instrumental set-up has been used during a field campaign during the winter 2013-214 in the Landes area in the South West of France. To validate the vertical profiles provided by the modified CDP, a mast was equipped with microphysical instruments at 2 altitude levels with an another CDP at 24 m and a Fog Monitor FM100 at 42 m. The instrumental set-up deployed during this campaign is presented. Data collected during a fog event that occurred during the night of 5-6 March 2014 are analysed. We show that microphysical properties such as droplet number concentration, LWC and mean droplet size, exhibit different time evolution during the fog life cycle depending on the altitude level. Droplet size distribution measurements are also investigated. They reveal sharp variations along the vertical close to the top of the fog layer. In addition it is shown that the shape of the size distributions at the top follows a time evolution typical of a quasi-adiabatic droplet growth.

  11. The limitations of using vertical cutoff rigidities determined from the IGRF magnetic field models for computing aircraft radiation dose.

    PubMed

    Smart, D F; Shea, M A

    2003-01-01

    Vertical cutoff rigidities derived from the International Geomagnetic Reference Fields (IGRF) are normally used to compute the radiation dose at a specific location and to organize the radiation dose measurements acquired at aircraft altitudes. This paper presents some of the usually ignored limits on the accuracy of the vertical cutoff rigidity models and describes some of the computational artifacts present in these models. It is noted that recent aircraft surveys of the radiation dose experienced along specific flight paths is sufficiently precise that the secular variation of the geomagnetic field is observable.

  12. Reconstruction of the vertical electron density profile based on vertical TEC using the simulated annealing algorithm

    NASA Astrophysics Data System (ADS)

    Jiang, Chunhua; Yang, Guobin; Zhu, Peng; Nishioka, Michi; Yokoyama, Tatsuhiro; Zhou, Chen; Song, Huan; Lan, Ting; Zhao, Zhengyu; Zhang, Yuannong

    2016-05-01

    This paper presents a new method to reconstruct the vertical electron density profile based on vertical Total Electron Content (TEC) using the simulated annealing algorithm. The present technique used the Quasi-parabolic segments (QPS) to model the bottomside ionosphere. The initial parameters of the ionosphere model were determined from both International Reference Ionosphere (IRI) (Bilitza et al., 2014) and vertical TEC (vTEC). Then, the simulated annealing algorithm was used to search the best-fit parameters of the ionosphere model by comparing with the GPS-TEC. The performance and robust of this technique were verified by ionosonde data. The critical frequency (foF2) and peak height (hmF2) of the F2 layer obtained from ionograms recorded at different locations and on different days were compared with those calculated by the proposed method. The analysis of results shows that the present method is inspiring for obtaining foF2 from vTEC. However, the accuracy of hmF2 needs to be improved in the future work.

  13. Vertical Profile Measurements of Formaldehyde and NO2 by means of the CU Airborne Multi-Axis DOAS instrument

    NASA Astrophysics Data System (ADS)

    Oetjen, H.; Baidar, S.; Coburn, S.; Ortega, I.; Dix, B. K.; Sinreich, R.; Volkamer, R.

    2010-12-01

    The University of Colorado airborne multi-axis differential optical absorption spectroscopy (CU AMAX-DOAS) instrument was operated on board the NOAA twin otter research aircraft to measure column abundances of reactive trace gases (e.g., NO2, formaldehyde, glyoxal, O4, BrO, and IO) during the CalNEx and CARES campaigns in California in May to July, 2010. Column observations of reactive trace gases provide means to bridge spatial scales between ground-based measurements, and satellite observations, and enable a more direct comparison with atmospheric models. However, the CU AMAX-DOAS features a novel telescope to collect scattered sunlight under discrete viewing angles providing the opportunity to obtain profile information of trace gases as well. This telescope was installed in a pylon pointing out of the side window of the aircraft and allows to flexibly scan most angles in front of the aircraft from the zenith to nadir geometry (only limited by the window openings in the pylon) as well as backwards down to about minus 20°. A motion compensation system is included to actively adjust the pointing of the telescope to compensate for aircraft angular movements in the vertical. Two spectrometers have been deployed covering wavelength ranges from 350-720 nm with a spectral resolution of ~2 nm full width at half maximum (FWHM) and 330-470 nm with 0.7 nm FWHM. The recorded spectra are analyzed with the well-known DOAS method to retrieve so-called slant column densities (SCDs) of absorbers. Sets of SCDs recorded at different viewing angles are converted into a vertical profile through experimentally constrained inverse modeling of radiative transfer. The angular scanning pattern of the telescope, as well as the flight plan was optimized to characterize the horizontal and vertical distribution of the trace gases. Especially, the variation of the flight altitude in combination with the scanning of different angles provides a powerful tool to obtain the detailed vertical

  14. Study of aerodynamic technology for VSTOL fighter/attack aircraft: Vertical attitude concept

    NASA Technical Reports Server (NTRS)

    Gerhardt, H. A.; Chen, W. S.

    1978-01-01

    The aerodynamic technology for a vertical attitude VSTOL (VATOL) supersonic fighter/attack aircraft was studied. The selected configuration features a tailless clipped delta wing with leading-edge extension (LEX), maneuvering flaps, top-side inlet, twin dry engines and vectoring nozzles. A relaxed static stability is employed in conjunction with the maneuvering flaps to optimize transonic performance and minimize supersonic trim drag. Control for subaerodynamic flight is obtained by gimballing the nozzles in combination with wing tip jets. Emphasis is placed on the development of aerodynamic characteristics and the identification of aerodynamic uncertainties. A wind tunnel test program is proposed to resolve these uncertainties and ascertain the feasibility of the conceptual design. Ship interface, flight control integration, crew station concepts, advanced weapons, avionics, and materials are discussed.

  15. ALADINA - an unmanned research aircraft for observing vertical and horizontal distributions of ultrafine particles within the atmospheric boundary layer

    NASA Astrophysics Data System (ADS)

    Altstädter, B.; Platis, A.; Wehner, B.; Scholtz, A.; Wildmann, N.; Hermann, M.; Käthner, R.; Baars, H.; Bange, J.; Lampert, A.

    2015-04-01

    This paper presents the unmanned research aircraft Carolo P360 "ALADINA" (Application of Light-weight Aircraft for Detecting IN situ Aerosol) for investigating the horizontal and vertical distribution of ultrafine particles in the atmospheric boundary layer (ABL). It has a wingspan of 3.6 m, a maximum take-off weight of 25 kg and is equipped with aerosol instrumentation and meteorological sensors. A first application of the system, together with the unmanned research aircraft MASC (Multi-Purpose Airborne Carrier) of the Eberhard Karls University of Tübingen (EKUT), is described. As small payload for ALADINA, two condensation particle counters (CPC) and one optical particle counter (OPC) were miniaturised by re-arranging the vital parts and composing them in a space-saving way in the front compartment of the airframe. The CPCs are improved concerning the lower detection threshold and the response time to less than 1.3 s. Each system was characterised in the laboratory and calibrated with test aerosols. The CPCs are operated in this study with two different lower detection threshold diameters of 11 and 18 nm. The amount of ultrafine particles, which is an indicator for new particle formation, is derived from the difference in number concentrations of the two CPCs (ΔN). Turbulence and thermodynamic structure of the boundary layer are described by measurements of fast meteorological sensors that are mounted at the aircraft nose. A first demonstration of ALADINA and a feasibility study were conducted in Melpitz near Leipzig, Germany, at the Global Atmosphere Watch (GAW) station of the Leibniz Institute for Tropospheric Research (TROPOS) on 2 days in October 2013. There, various ground-based instruments are installed for long-term atmospheric monitoring. The ground-based infrastructure provides valuable additional background information to embed the flights in the continuous atmospheric context and is used for validation of the airborne results. The development of the

  16. ALADINA - an unmanned research aircraft for observing vertical and horizontal distributions of ultrafine particles within the atmospheric boundary layer

    NASA Astrophysics Data System (ADS)

    Altstädter, B.; Platis, A.; Wehner, B.; Scholtz, A.; Lampert, A.; Wildmann, N.; Hermann, M.; Käthner, R.; Bange, J.; Baars, H.

    2014-12-01

    This paper presents the unmanned research aircraft Carolo P360 "ALADINA" (Application of Light-weight Aircraft for Detecting IN-situ Aerosol) for investigating the horizontal and vertical distribution of ultrafine particles in the atmospheric boundary layer (ABL). It has a wingspan of 3.6 m, a maximum take-off weight of 25 kg and is equipped with aerosol instrumentation and meteorological sensors. A first application of the system, together with the unmanned research aircraft MASC (Multi-Purpose Airborne Carrier) of the Eberhard-Karls University of Tübingen (EKUT), is described. As small payload for ALADINA, two condensation particle counters (CPC) and one optical particle counter (OPC) were miniaturized by re-arranging the vital parts and composing them in a space saving way in the front compartment of the airframe. The CPCs are improved concerning the lower detection threshold and the response time. Each system was characterized in the laboratory and calibrated with test aerosols. The CPCs are operated with two different lower detection threshold diameters of 6 and 18 nm. The amount of ultrafine particles, which is an indicator for new particle formation, is derived from the difference in number concentrations of the two CPCs. Turbulence and thermodynamic structure of the boundary layer are described by measurements of fast meteorological sensors that are mounted at the aircraft nose. A first demonstration of ALADINA and a feasibility study were conducted in Melpitz near Leipzig, Germany, at the Global Atmosphere Watch (GAW) station of the Leibniz Institute for Tropospheric Research (TROPOS) on two days in October 2013. There, various ground-based instruments are installed for long-term atmospheric monitoring. The ground-based infrastructure provides valuable additional background information to embed the flights in the continuous atmospheric context and is used for validation of the airborne results. The development of the boundary layer, derived from

  17. How well can we Measure the Vertical Profile of Tropospheric Aerosol Extinction?

    NASA Technical Reports Server (NTRS)

    Schmid, Beat; Ferrare, R.; Flynn, C.; Elleman, R.; Covert, D.; Strawa, A.; Welton, E.; Turner, D.; Jonsson, H.; Redemann, J.

    2005-01-01

    The recent Department of Energy Atmospheric Radiation Measurement (ARM) Aerosol Intensive Operations Period (MOP, May 2003) yielded one of the best measurement sets obtained to-date to assess our ability to measure the vertical profile of ambient aerosol extinction sigma(sub ep)(lambda) in the lower troposphere. During one month, a heavily instrumented aircraft with well characterized aerosol sampling ability carrying well proven and new aerosol instrumentation, devoted most of the 60 available flight hours to flying vertical profiles over the heavily instrumented ARM Southern Great Plains (SGP) Climate Research Facility (CRF). This allowed us to compare vertical extinction profiles obtained from 6 different instuments: airborne Sun photometer (AATS-14), airborne nephelometer/absorption photometer, airborne cavity ring-down system, ground-based Raman lidar and 2 ground-based elastic backscatter lidars. We find the in-situ measured sigma(sub ep)(lambda) to be lower than the AATS-14 derived values. Bias differences are 0.002 - 0.004 K/m equivalent to 12-17% in the visible, or 45% in the near-infrared. On the other hand, we find that with respect to AATS-14, the lidar sigma(sub ep)(lambda) are higher. An unnoticed loss of sensitivity of the Raman lidar had occurred leading up to AIOP and we expect better agreement from the recently restored system looking at the collective results from 6 field campaigns conducted since 1996, airborne in situ measurements of sigma(sub ep)(lambda) tend to be biased slightly low (17% at visible wavelengths) when compared to airborne Sun photometer sigma(sub ep)(lambda). On the other hand, sigma(sub ep)(lambda) values derived from lidars tend to have no or positive biases. From the bias differences we conclude that the typical systematic error associated with measuring the tropospheric vertical profile of the ambient aerosol extinction with current state of-the art instrumentation is 15-20% at visible wavelengths and potentially larger in

  18. Study of a subsurface fracture zone by vertical seismic profiling

    NASA Astrophysics Data System (ADS)

    Stewart, Robert R.; Turpening, Roger M.; Toksoz, M. Nafi

    Remotely estimating the properties of subsurface fracture zones is important in characterizing the structure of the shallow earth. We present a vertical seismic profiling (VSP) technique to make this fracture zone estimation and discuss the results of a VSP experiment performed in the upper 770 m of the Michigan Basin. Both P and SH waves were used to observe an explosively-fractured volume of Antrim shale. The experiment was divided into two parts: a "before" survey run on the unaltered rock, then an identical "after" survey executed across the fractured volume. A seismic velocity structure of the basin was calculated from the "before" survey. Comparison of the "after" observations to the "before" data, elucidated the fracture volume and its effective elastic parameters. From travel-time delays, amplitude attenuation, converted and scattered waves, we estimated the depth (395 m), shape (ellipsoidal), size (10 m × 20 m × 30 m) and porosity (20%) of the fracture zone.

  19. Aircraft Measurements of Convective System Vertical Structure and Coldpools during the DYNAMO Project

    NASA Astrophysics Data System (ADS)

    Guy, N.; Jorgensen, D. P.; Chen, S. S.; Wang, Q.

    2012-12-01

    The DYNAMO (Dynamics of the Madden-Julian Oscillation) field experiment employed a large number of measurement platforms with which to study environmental and convective cloud system characteristics of the MJO initiation region in the Indian Ocean. One such platform, the NOAA P-3 instrumented aircraft, provided mobility to sample convective cloud systems along with the surrounding environment. The tail-mounted, X-band Doppler radar allowed a pseudo-dual-Doppler analysis technique to study system kinematics and derive vertical wind motion. GPS dropwindsondes provided a robust means for thermodynamic characterization both in and around the sampled convective cloud systems. This presentation will focus on the relationships between coldpool strength and depth (along with other environmental characteristics) and the vertical structure of convective systems. In addition, a comparison of the DYNAMO observations to previous results in the region (e.g. TOGA COARE) will be presented. Differences in organizational aspects of convective clouds into mesoscale convective systems between the studies will provide a context of regional differences, which may serve as a basis for future model simulations.

  20. Vertical Profile of Aerosol Properties at Pico Mountain, Azores

    NASA Astrophysics Data System (ADS)

    Wright, K.; Mazzoleni, C.; Mazzoleni, L. R.; Dzepina, K.; Hueber, J.; China, S.; Sharma, N.

    2013-12-01

    Pico Mountain (2325m asl) is a dormant volcano in the archipelago of the Azores1500 km west of Lisbon, Portugal in the North Atlantic. It differs from typical mountain ranges such as the Alps or the Rockies, which are large and present a complex orography. Pico Mountain has a simple cone-like structure with only one main peak and is thousands of kilometers away from any other significant mountain range. In summer months, it is typical for air masses to move around the mountain rather than traveling up its face. This implies that often the peak of the mountain lies above the marine boundary layer in the free troposphere, while the lower part of the mountain is affected by marine clouds and marine air-masses. An atmospheric monitoring station, the Pico Mountain Observatory was established in 2001 in the summit caldera of the volcano at 2225m above sea level. The observatory is far from large populations or pollution sources, which makes the station ideal to study atmospheric gases and aerosols transported over long-ranges in the free troposphere. The station is reachable only by foot following a steep and strenuous hiking trail. In the summer of 2013 we began to collect vertical profiles of aerosol by carrying an instrumented backpack up to the summit of the mountain, with the goal of studying the vertical structure of atmospheric aerosols from the marine boundary layer to the free troposphere. The backpack was carried from the base of trail at 1200m asl. The backpack was equipped with the following instruments: 1. Nephelometer to measure light scattering from aerosol 2. 2-size optical particle counter (300-500 nm) 3. Portable micro-aethalometer to measure absorbing aerosols 4. SEM/TEM sampler to collect particles for off-line electron microscopy analysis 5. Battery powered data logger to measure relative humidity, temperature and pressure 6. GPS tracking device We provide a preliminary analysis of data collected in 2013 to gain insight on the vertical distribution

  1. Turbulence length scales in stably stratified free shear flow analyzed from slant aircraft profiles

    SciTech Connect

    Tjernstroem, M. )

    1993-05-01

    The vertical turbulence structure in the marine atmosphere close to a coastline is investigated using airborne measurements. The measurements are from a field experiment close to the coast in the southeast of Sweden, in the Baltic Sea. The Baltic Sea has two main properties that make it particularly interesting to study: significant annual lag in sea surface temperature compared to inland surface temperatures and the fact that it is surrounded by land in all directions within advection distances of from a few hours up to 10-15 hours in normal meteorological conditions. The present results are mostly from spring or early summer with mainly cool water: with a stable or neutral marine boundary layer but with substantial heating of the land area during daytime. When the daytime inland convective boundary layer is advected out over the cool sea, there is a frictional decoupling in space analogous to the same nocturnal process in time. This sometimes creates a residual layer, a remnant of the inland convective boundary layer, that can be advected for considerable distances over the sea. At the top of this layer, wind shear gives rise to a local increase in turbulent kinetic energy. These layers are used for an analysis of turbulent scales for free shear flow in stable stratification. The analysis is based on different length scales used in numerical model closures for turbulence processes and reveals the asymptotic behavior of different scales in the neutral limit and their functional form, and illustrates the nonlinear relationship between scales for different properties. The profiles from the aircraft are taken from 25 slant soundings performed in connection to low-level boundary-layer flights. The results are calculated from turbulence data extracted through filtering techniques on instantaneous time series (individual profiles). The calculated turbulence parameters from all profiles are grouped and averaged compositely over all profiles. 48 refs., 12 figs., 1 tab.

  2. Profile design for an advanced-technology airfoil for general aviation aircraft

    NASA Technical Reports Server (NTRS)

    Welte, D.

    1978-01-01

    A profile from the NASA General Aviation Whitcomb series and NACA profiles are used as a starting point in designing an advanced airfoil for general aviation aircraft. Potential theory pressure distribution calculations, together with boundary layer calculations, permit a decrease in the null moment and an optimization of the lift characteristics of the wing. Trailing edge flap design is also improved. Wind tunnel tests are used to compare the conventional profiles, the NASA profile, and the improved design.

  3. New approach for aerosol profiling with a lidar onboard an ultralight aircraft: application to the African Monsoon Multidisciplinary Analysis.

    PubMed

    Chazette, Patrick; Sanak, Joseph; Dulac, François

    2007-12-15

    A new airborne instrumental payload has been designed for an ultralight aircraft to determine the vertical profile of aerosol optical properties. It is based on Lidar Aérosols UltraViolet Aéroporté (LAUVA), a compact backscattering lidar system emitting at the wavelength of 355 nm. We operated this airborne configuration in the Sahel from the city of Niamey (Niger) during the first campaign of the African Monsoon Multidisciplinary Analysis (AMMA) in January-February 2006, when aerosols from both soil dust and savannah fires cause large visibility reductions. We take advantage of the lidar capability of pointing in different directions for retrieving the vertical profile of the aerosol backscatter to extinction ratio (BER). A synergy with a scatterometer (880 nm) and a ground-based sunphotometer allows us to further determine the vertical profile of Angström exponent (a). We identify three types of aerosol layers up to about 5 km below the free troposphere, dominated by biomass burning (BB) particles, mineral dust (D) particles, and a mixing between BB and D particles, respectively, associated with BER (a) values close to 0.008 sr(-1) (1.5), 0.025 sr(-1) (0), and 0.015 sr(-1) (0.4-1).

  4. Deriving Vertical Profiles of Aerosol Sizes from TES

    NASA Astrophysics Data System (ADS)

    Wolff, M. J.; Clancy, R. T.; Smith, M. D.; McConnochie, T. H.; Flittner, D. E.; Fouchet, T.

    2011-12-01

    Vertical variations in aerosol particle sizes can have a dramatic effect in their net impact on the state and evolution of the Martian atmosphere. Recent analyses of data from the Spectroscopy for the Investigation of the Characteristics of the Atmosphere of Mars (SPICAM) and the Thermal Emission Spectrometer (TES) instruments offer some long overdue progress in constraining this aspect of aerosols. However, significantly more work remains to be done along these lines in order to better constrain and inform modern dynamical simulations of the Martian atmosphere. Thus, the primary goal of our work is to perform retrievals of particle size as a function of altitude for both dust and water ice aerosols. The choice of the TES dataset, with pole-to-pole coverage over a period of nearly three martian years, provides the crucial systematic temporal and spatial sampling. Additional leverage on the particle size will be obtained by using both solarband bolometry and infrared (IR) spectroscopy. Our presentation will include: 1) A summary of our limb radiative transfer comparison/validation exercises which include Monte Carlo, Gauss-Seidel, and discrete-ordinate algorithms (including the plane-parallel source function approximation). 2) The initial results of the application of our particle size retrieval scheme to the TES observations of the 2001 planet encircling dust event. 3) A few test applications to the Mars Climate Sounder (MCS) radiance profiles (enabled by the recent solarband radiometric calibration by Bandfield and collaborators). 4) Our plans for additional retrievals (aphelion cloud season, lower optical depth locations and seasons, etc.) and the distribution of the derived profiles.

  5. FIRE aircraft observations of horizontal and vertical transport in marine stratocumulus

    NASA Technical Reports Server (NTRS)

    Paluch, Ilga R.; Lenschow, Donald H.

    1990-01-01

    A major goal of research on marine stratocumulus is to try to understand the processes that generate and dissipate them. One approach to studying this problem is to investigate the boundary layer structure in the vicinity of a transition from a cloudy to a cloud-free region to document the differences in structure on each side of the transition. Since stratiform clouds have a major impact on the radiation divergence in the boundary layer, the transition from a cloudy to a clear boundary layer is a region of large horizontal inhomogeneity in air temperature and turbulence intensity. This leads to a considerable difference in horizontal and vertical transports between the cloudy and cloud-free regions. Measurements are used from the NCAR Electra aircraft during flights 5 (7 July 1987) and 10 (18 July 1987) of FIRE for this purpose. Flight 5 coincided with a LANDSAT overflight, and was designed to investigate the transition across a well-defined N-S cloud boundary, since the LANDSAT image can document the cloud cover in considerable detail. Turbulence legs were flown about 60 km on both sides of the cloud boundary. Flight 10 was flown at night in an area of scattered small cumuli and broken cloud patches.

  6. 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...

  7. Remote Sensing the Vertical Profile of Cloud Droplet Effective Radius, Thermodynamic Phase, and Temperature

    NASA Technical Reports Server (NTRS)

    Martins, J. V.; Marshak, A.; Remer, L. A.; Rosenfeld, D.; Kaufman, Y. J.; Fernandez-Borda, R.; Koren, I.; Correia, A. L.; Zubko, V.; Artaxo, P.

    2011-01-01

    Cloud-aerosol interaction is a key issue in the climate system, affecting the water cycle, the weather, and the total energy balance including the spatial and temporal distribution of latent heat release. Information on the vertical distribution of cloud droplet microphysics and thermodynamic phase as a function of temperature or height, can be correlated with details of the aerosol field to provide insight on how these particles are affecting cloud properties and their consequences to cloud lifetime, precipitation, water cycle, and general energy balance. Unfortunately, today's experimental methods still lack the observational tools that can characterize the true evolution of the cloud microphysical, spatial and temporal structure in the cloud droplet scale, and then link these characteristics to environmental factors and properties of the cloud condensation nuclei. Here we propose and demonstrate a new experimental approach (the cloud scanner instrument) that provides the microphysical information missed in current experiments and remote sensing options. Cloud scanner measurements can be performed from aircraft, ground, or satellite by scanning the side of the clouds from the base to the top, providing us with the unique opportunity of obtaining snapshots of the cloud droplet microphysical and thermodynamic states as a function of height and brightness temperature in clouds at several development stages. The brightness temperature profile of the cloud side can be directly associated with the thermodynamic phase of the droplets to provide information on the glaciation temperature as a function of different ambient conditions, aerosol concentration, and type. An aircraft prototype of the cloud scanner was built and flew in a field campaign in Brazil.

  8. 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.

  9. Vertical velocities within a Cirrus cloud from Doppler lidar and aircraft measurements during FIRE: Implications for particle growth

    NASA Technical Reports Server (NTRS)

    Gultepe, Ismail; Heymsfield, Andrew J.

    1990-01-01

    A large and comprehensive data set taken by the NOAA CO2 Doppler lidar, the NCAR King Air, and rawinsondes on 31 October 1986 during the FIRE (First ISCCP Regional Experiment) field program which took place in Wisconsin are presented. Vertical velocities are determined from the Doppler lidar data, and are compared with velocities derived from the aircraft microphysical data. The data are used for discussion of particle growth and dynamical processes operative within the cloud.

  10. Aerodynamically controlled expansion (ACE) nozzle for short takeoff and vertical landing aircraft

    NASA Astrophysics Data System (ADS)

    Terrier, Douglas Anthony

    2000-10-01

    An Aerodynamically Controlled Expansion (ACE) propulsion nozzle that improves hover thrust performance by 2.5 percent in a short take off and vertical landing (STOVL) aircraft has been developed. The ACE concept employs a carefully defined step in the nozzle internal contour that interacts with the boundary layer to induce flow separation in the divergent section, thereby relieving over-expansion losses during hover. This study specifies design parameters for a passive boundary layer control step for application on the Joint Strike Fighter (JSF). In addition, parametric performance predictions presented herein provide a basic understanding of how the step concept can be applied to overcome undesirable over-expansion in generalized supersonic nozzle flows. The aerodynamic phenomena governing the interaction of the step with the nozzle flow were investigated in an extensive, parametric CFD analysis. The CFD analysis matrix consists of thirty-three axi-symmetric nozzle cases including expansion area ratios (A9/A 8) of 1.1, 1.3 and 1.5, slot area ratios (A s/A8) of 1.0 (baseline), 1.1 and 1.2, and covering the nozzle pressure ratio (NPR) range of 2.0 to 8.0. The CFD results define the NPR at which flow separation occurs as a function of A9/A8, and A s/A8, and the effect of the step on nozzle performance. Results indicate that the onset of separation occurs at higher NPR with increasing A9/A 8 and increasing As/A 8. For the case of the JSF nozzle with A9/ A8 = 1.3, the CFD analysis predicted that a nozzle having an As/A8 = 1.1 produces an improvement of approximately 2.5 percent in hover thrust relative to the baseline with a minimal adverse impact at other design conditions. Twelve percent scale models representing the baseline, and step sizes of 1.1 and 1.2 were tested in the Lockheed Martin Thrust Measurement Facility (TMF). Test results showed excellent agreement with CFD predictions and validated the step performance. Preliminary design integration studies support

  11. Vertical particle concentration profiles around urban office buildings

    NASA Astrophysics Data System (ADS)

    Quang, T. N.; He, C.; Morawska, L.; Knibbs, L. D.; Falk, M.

    2012-06-01

    Despite its role in determining both indoor and outdoor human exposure to anthropogenic particles, there is limited information describing vertical profiles of particle concentrations in urban environments, especially for ultrafine particles. Furthermore, the results of the few studies performed have been inconsistent. As such, this study aimed to assess the influence of vehicle emissions and nucleation formation on particle characteristics (particle number size distribution - PNSD and PM2.5 concentration) at different heights around three urban office buildings located next to busy roads in Brisbane, Australia, and place these results in the broader context of the existing literature. Two sets of instruments were used to simultaneously measure PNSD, particle number (PN) and PM2.5 concentrations, respectively, for up to three weeks at each building. The results showed that both PNSD and PM2.5 concentration around building envelopes were influenced by vehicle emissions and new particle formation, and that they exhibited variability across the three different office buildings. During nucleation events, PN concentration in size range of <30 nm and total PN concentration increased (7-65% and 5-46%, respectively), while PM2.5 concentration decreased (36-52%) with height. This study has shown an under acknowledged role for nucleation in producing particles that can affect large numbers of people, due to the high density and occupancy of urban office buildings and the fact that the vast majority of people's time is spent indoors. These findings highlight important new information related to the previously overlooked role of particle formation in the urban atmosphere and its potential effects on selection of air intake locations and appropriate filter types when designing or upgrading mechanical ventilation systems in urban office buildings. The results also serve to better define particle behaviour and variability around building envelopes, which has implications for

  12. Radiosonde aerosol counter for vertical profiling of atmospheric dust layers

    NASA Astrophysics Data System (ADS)

    Ulanowski, Z.; Hirst, E.; Kaye, P. H.; Harrison, R. G.; Nicoll, K. A.; Rogers, G.

    2010-05-01

    A low-cost, miniature aerosol particle counter has been developed, intended for use with balloon-borne meteorological radiosondes. It is particularly suitable for airborne mineral dust measurements. Ambient air is drawn into the counter using a diaphragm pump at a rate of 0.5 litre per minute. The counter detects particles in the airstream using a diode laser and a photodiode. Output from the photodiode is digitised into 5 size bins, with minimum particle diameters equivalent to 0.6, 1.4, 2.6, 5.4 and 10.6 micrometers. The counter is interfaced to a Vaisala RS92 radiosonde, which transmits data from the counter together with meteorological parameters and GPS-derived position to a ground based receiver at 1 Hz rate. Statistically significant particle size distributions can be obtained once a second for number concentrations down to about 100,000 particle per litre (within the measured size range), or correspondingly less at lower temporal resolutions. At the same time, the counter is capable of measuring dust number concentrations exceeding a million per litre without incurring significant errors. Soundings during the DREAME campaign in Kuwait (Ulanowski et al. EGU 2010, AS4.7) and on Cape Verde Islands (Nicoll et al. EGU 2010, AS4.7) provided dust concentration profiles with a typical vertical resolution of 4 m. Comparisons with integrated dust column size distribution measurements from AERONET sun photometers showed good agreement in two out of three cases where near-simultaneous retrievals were available. Optical thickness calculations based on the size distributions measured in Kuwait, with the assumption that the dust particles were prolate spheroids, agreed with the AERONET optical thickness at 675 nm to within 15%.

  13. Development of an Aircraft Approach and Departure Atmospheric Profile Generation Algorithm

    NASA Technical Reports Server (NTRS)

    Buck, Bill K.; Velotas, Steven G.; Rutishauser, David K. (Technical Monitor)

    2004-01-01

    In support of NASA Virtual Airspace Modeling and Simulation (VAMS) project, an effort was initiated to develop and test techniques for extracting meteorological data from landing and departing aircraft, and for building altitude based profiles for key meteorological parameters from these data. The generated atmospheric profiles will be used as inputs to NASA s Aircraft Vortex Spacing System (AVOLSS) Prediction Algorithm (APA) for benefits and trade analysis. A Wake Vortex Advisory System (WakeVAS) is being developed to apply weather and wake prediction and sensing technologies with procedures to reduce current wake separation criteria when safe and appropriate to increase airport operational efficiency. The purpose of this report is to document the initial theory and design of the Aircraft Approach Departure Atmospheric Profile Generation Algorithm.

  14. IO in the Lower Stratosphere and Vertical Profiles over the Tropical Eastern and Western Pacific

    NASA Astrophysics Data System (ADS)

    Koenig, T. K.; Volkamer, R. M.; Baidar, S.; Dix, B. K.; Evans, M. J.; Carpenter, L.; Sherwen, T.; Kinnison, D. E.; Lamarque, J. F.; Saiz-Lopez, A.; Apel, E. C.; Hornbrook, R. S.; Atlas, E. L.; Pan, L.; Salawitch, R. J.

    2014-12-01

    Iodine Monoxide (IO) is a halogen radical species that catalytically destroys ozone, modifies the atmosphere's oxidative capacity and is a precursor to aerosol particle formation and growth. Measurements of IO are generally scarce, and only very few observations have recently detected IO as widespread in the tropical free troposphere. Here we report on IO observations by the CU Airborne MAX-DOAS instrument aboard the NSF/NCAR GV aircraft during the CONvective TRansport of Active Species in the Tropics (CONTRAST) and Tropical Ocean tRoposphere Exchange of Reactive halogen species and Oxygenated VOC (TORERO) field campaigns. We have measured IO vertical profiles over the tropical and sub-tropical Western and Eastern Pacific Ocean, including a detection of IO in the UTLS and lower stratosphere. Our measurements indicate IO abundances that are 2-3 times higher in the Southern hemisphere than in the Northern hemisphere free troposphere. Measurements in the lower stratosphere and tropical UTLS provide the first quantification of IO in these layers by limb observations of scattered sunlight. We compare these observations with predictions from the global models CAMChem and GEOSChem.

  15. Development of a Climatology of Vertically Complete Wind Profiles from Doppler Radar Wind Profiler Systems

    NASA Technical Reports Server (NTRS)

    Barbre, Robert E., Jr.

    2015-01-01

    This paper describes in detail the QC and splicing methodology for KSC's 50- and 915-MHz DRWP measurements that generates an extensive archive of vertically complete profiles from 0.20-18.45 km. The concurrent POR from each archive extends from April 2000 to December 2009. MSFC NE applies separate but similar QC processes to each of the 50- and 915-MHz DRWP archives. DRWP literature and data examination provide the basis for developing and applying the automated and manual QC processes on both archives. Depending on the month, the QC'ed 50- and 915-MHz DRWP archives retain 52-65% and 16-30% of the possible data, respectively. The 50- and 915-MHz DRWP QC archives retain 84-91% and 85-95%, respectively, of all the available data provided that data exist in the non- QC'ed archives. Next, MSFC NE applies an algorithm to splice concurrent measurements from both DRWP sources. Last, MSFC NE generates a composite profile from the (up to) five available spliced profiles to effectively characterize boundary layer winds and to utilize all possible 915-MHz DRWP measurements at each timestamp. During a given month, roughly 23,000-32,000 complete profiles exist from 0.25-18.45 km from the composite profiles' archive, and approximately 5,000- 27,000 complete profiles exist from an archive utilizing an individual 915-MHz DRWP. One can extract a variety of profile combinations (pairs, triplets, etc.) from this sample for a given application. The sample of vertically complete DRWP wind measurements not only gives launch vehicle customers greater confidence in loads and trajectory assessments versus using balloon output, but also provides flexibility to simulate different DOL situations across applicable altitudes. In addition to increasing sample size and providing more flexibility for DOL simulations in the vehicle design phase, the spliced DRWP database provides any upcoming launch vehicle program with the capability to utilize DRWP profiles on DOL to compute vehicle steering

  16. Aircraft

    DOEpatents

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

    1998-09-22

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

  17. Aircraft

    DOEpatents

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

    1998-01-01

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

  18. Reconstruction of Vertical Profile of Permittivity of Layered Media which is Probed Using Vertical Differential Antenna

    NASA Astrophysics Data System (ADS)

    Pochanin, Gennadiy P.; Poyedinchuk, Anatoliy Y.; Varianytsia-Roshchupkina, Liudmyla A.; Pochanina, Iryna Ye.

    2016-04-01

    Results of this research are intended to use at GPR investigations of layered media (for example, at roads' inspection) for the processing of collected data and reconstruction of dependence of permittivity on the depth. Recently, an antenna system with a vertical differential configuration of receiving module (Patent UA81652) for GPR was suggested and developed The main advantage of the differential antennas in comparison with bistatic antennas is a high electromagnetic decoupling between the transmitting and receiving modules. The new vertical differential configuration has an additional advantage because it allows collecting GPR data reflected by layered media without any losses of information about these layers [1] and, potentially, it is a more accurate instrument for the layers thickness measurements [2]. The developed antenna system is tested in practice with the GPR at asphalt thickness measurements [3] and shown an accuracy which is better than 0.5 cm. Since this antenna system is good for sounding from above the surface (air coupled technique), the mobile laboratory was equipped with the developed GPR [3]. In order to process big set of GPR data that collected during probing at long routes of the roads, for the data processing it was tested new algorithm of the inverse problem solution. It uses a fast algorithm for calculation of electromagnetic wave diffraction by non-uniform anisotropic layers [4]. The algorithm is based on constructing a special case solution to the Riccati equation for the Cauchy problem and enables a qualitative description of the wave diffraction by the electromagnetic structure of the type within a unitary framework. At this stage as initial data we used synthetic GPR data that were obtained as results of the FDTD simulation of the problem of UWB electromagnetic impulse diffraction on layered media. Differential and bistatic antenna configurations were tested at several different profiles of permittivity. Meanings of permittivity of

  19. Remote measurements of ozone, water vapor and liquid water content, and vertical profiles of temperature in the lower troposphere

    NASA Technical Reports Server (NTRS)

    Grant, W. B.; Gary, B. L.; Shumate, M. S.

    1983-01-01

    Several advanced atmospheric remote sensing systems developed at the Jet Propulsion Laboratory were demonstrated under various field conditions to determine how useful they would be for general use by the California Air Resources Board and local air quality districts. One of the instruments reported on is the Laser Absorption Spectrometer (LAS). It has a pair of carbon dioxide lasers with a transmitter and receiver and can be flown in an aircraft to measure the column abundance of such gases as ozone. From an aircraft, it can be used to rapidly survey a large region. The LAS is usually operated from an aircraft, although it can also be used at a fixed location on the ground. Some tests were performed with the LAS to measure ozone over a 2-km horizontal path. Another system reported on is the Microwave Atmospheric Remote Sensing System (MARS). It is tuned to microwave emissions from water vapor, liquid water, and oxygen molecules (for atmospheric temperature). It can measure water vapor and liquid water in the line-of-sight, and can measure the vertical temperature profile.

  20. GROUND WATER SAMPLING FOR VERTICAL PROFILING OF CONTAMINANTS

    EPA Science Inventory

    Accurate delineation of plume boundaries and vertical contaminant distribution are necessary in order to adequately characterize waste sites and determine remedial strategies to be employed. However, it is important to consider the sampling objectives, sampling methods, and sampl...

  1. Insights Into Precipitation Processes As Revealed By Profiling Radar, Disdrometer and Aircraft Observations During The MC3E Campaign.

    NASA Astrophysics Data System (ADS)

    Giangrande, S. E.; Toto, T.; Mishra, S.; Ryzhkov, A.; Bansemer, A.; Kumjian, M.

    2014-12-01

    The Midlatitude Continental Convective Clouds Experiment (MC3E) was a collaborative campaign led by the National Aeronautic and Space Administration's (NASA's) Global Precipitation Measurement (GPM) mission and the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) program. This campaign was held at the DOE ARM Southern Great Plains (SGP) Central Facility (CF) in north-central Oklahoma, with the programs joining forces to deploy an extensive array of airborne, radiosonde and ground-based instrumentation towards an unprecedented set of deep convective environment and cloud property observations. An overarching motivation was to capitalize on the wealth of aircraft observations and new multi-frequency dual-polarization radars to provide insights for improving the treatments of cloud processes in convective models. This study considers a coupled aircraft, radar and surface disdrometer approach for identifying key cloud processes and linking those to possible radar-based microphysical fingerprints and/or cloud properties. Our emphasis is on the MC3E observations collected during aircraft spirals over the column of the ARM CF. We focus on those spirals associated with radar 'bright band' signatures and Doppler spectral anomalies observed within trailing stratifrom precipitation. Two cases are highlighted, one following a weaker convective event, and one following a stronger squall line. For each event, we investigate the usefulness of radar to inform on processes including aggregation and riming as viewed by the vertically-pointing ARM wind profiler (915 MHz) and cloud radar Doppler spectral observations (35 GHz). Matching dual-polarization radar signatures from nearby cm-wavelength radar are also consulted for complementary insights. For one event, the successive Citation II aircraft spirals through the melting layer and associated ground observations indicate a fortunate capture of the transition from a region of riming to one favoring aggregation

  2. Minimum-Cost Aircraft Descent Trajectories with a Constrained Altitude Profile

    NASA Technical Reports Server (NTRS)

    Wu, Minghong G.; Sadovsky, Alexander V.

    2015-01-01

    An analytical formula for solving the speed profile that accrues minimum cost during an aircraft descent with a constrained altitude profile is derived. The optimal speed profile first reaches a certain speed, called the minimum-cost speed, as quickly as possible using an appropriate extreme value of thrust. The speed profile then stays on the minimum-cost speed as long as possible, before switching to an extreme value of thrust for the rest of the descent. The formula is applied to an actual arrival route and its sensitivity to winds and airlines' business objectives is analyzed.

  3. Integrated control and display research for transition and vertical flight on the NASA V/STOL Research Aircraft (VSRA)

    NASA Technical Reports Server (NTRS)

    Foster, John D.; Moralez, Ernesto, III; Franklin, James A.; Schroeder, Jeffery A.

    1987-01-01

    Results of a substantial body of ground-based simulation experiments indicate that a high degree of precision of operation for recovery aboard small ships in heavy seas and low visibility with acceptable levels of effort by the pilot can be achieved by integrating the aircraft flight and propulsion controls. The availability of digital fly-by-wire controls makes it feasible to implement an integrated control design to achieve and demonstrate in flight the operational benefits promised by the simulation experience. It remains to validate these systems concepts in flight to establish their value for advanced short takeoff vertical landing (STOVL) aircraft designs. This paper summarizes analytical studies and simulation experiments which provide a basis for the flight research program that will develop and validate critical technologies for advanced STOVL aircraft through the development and evaluation of advanced, integrated control and display concepts, and lays out the plan for the flight program that will be conducted on NASA's V/STOL Research Aircraft (VSRA).

  4. Test-Analysis Correlation of a Crash Simulation of a Vertical Drop Test of a Commuter-Category Aircraft

    NASA Technical Reports Server (NTRS)

    Jackson, Karen E.; Fasanella, Edwin L.

    2004-01-01

    A finite element model of an ATR42-300 commuter-class aircraft was developed and a crash simulation was executed. Analytical predictions were correlated with data obtained from a 30-feet per second (9.14-meters per second) vertical drop test of the aircraft. The purpose of the test was to evaluate the structural response of the aircraft when subjected to a severe, but survivable, impact. The aircraft was configured with seats, dummies, luggage, and other ballast. The wings were filled with 8,700 lb. (3,946 kilograms) of water to represent the fuel. The finite element model, which consisted of 57,643 nodes and 62,979 elements, was developed from direct measurements of the airframe geometry. The seats, dummies, luggage, simulated engines and fuel, and other ballast were represented using concentrated masses. The model was executed in LS-DYNA, a commercial finite element code for performing explicit transient dynamic simulations. Analytical predictions of structural deformation and selected time-history responses were correlated with experimental data from the drop test to validate the simulation.

  5. Decision-Aiding and Optimization for Vertical Navigation of Long-Haul Aircraft

    NASA Technical Reports Server (NTRS)

    Patrick, Nicholas J. M.; Sheridan, Thomas B.

    1996-01-01

    Most decisions made in the cockpit are related to safety, and have therefore been proceduralized in order to reduce risk. There are very few which are made on the basis of a value metric such as economic cost. One which can be shown to be value based, however, is the selection of a flight profile. Fuel consumption and flight time both have a substantial effect on aircraft operating cost, but they cannot be minimized simultaneously. In addition, winds, turbulence, and performance x,ary widely with altitude and time. These factors make it important and difficult for pilots to (a) evaluate the outcomes associated with a particular trajectory before it is flown and (b) decide among possible trajectories. The two elements of this problem considered here are (1) determining, what constitutes optimality, and (2) finding optimal trajectories. Pilots and dispatchers from major U.S. airlines were surveyed to determine which attributes of the outcome of a flight they considered the most important. Avoiding turbulence-for passenger comfort topped the list of items which were not safety related. Pilots' decision making about the selection of flight profile on the basis of flight time, fuel burn, and exposure to turbulence was then observed. Of the several behavioral and prescriptive decision models invoked to explain the pilots' choices, utility maximization is shown to best reproduce the pilots' decisions. After considering more traditional methods for optimizing trajectories, a novel method is developed using a genetic algorithm (GA) operating on a discrete representation of the trajectory search space. The representation is a sequence of command altitudes, and was chosen to be compatible with the constraints imposed by Air Traffic Control, and with the training given to pilots. Since trajectory evaluation for the GA is performed holistically, a wide class of objective functions can be optimized easily. Also, using the GA it is possible to compare the costs associated with

  6. Decision-Aiding and Optimization for Vertical Navigation of Long-Haul Aircraft

    NASA Technical Reports Server (NTRS)

    Patrick, Nicholas J. M.; Sheridan, Thomas B.

    1996-01-01

    Most decisions made in the cockpit are related to safety, and have therefore been proceduralized in order to reduce risk. There are very few which are made on the basis of a value metric such as economic cost. One which can be shown to be value based, however, is the selection of a flight profile. Fuel consumption and flight time both have a substantial effect on aircraft operating cost, but they cannot be minimized simultaneously. In addition, winds, turbulence, and performance vary widely with altitude and time. These factors make it important and difficult for pilots to (a) evaluate the outcomes associated with a particular trajectory before it is flown and (b) decide among possible trajectories. The two elements of this problem considered here are: (1) determining what constitutes optimality, and (2) finding optimal trajectories. Pilots and dispatchers from major u.s. airlines were surveyed to determine which attributes of the outcome of a flight they considered the most important. Avoiding turbulence-for passenger comfort-topped the list of items which were not safety related. Pilots' decision making about the selection of flight profile on the basis of flight time, fuel burn, and exposure to turbulence was then observed. Of the several behavioral and prescriptive decision models invoked to explain the pilots' choices, utility maximization is shown to best reproduce the pilots' decisions. After considering more traditional methods for optimizing trajectories, a novel method is developed using a genetic algorithm (GA) operating on a discrete representation of the trajectory search space. The representation is a sequence of command altitudes, and was chosen to be compatible with the constraints imposed by Air Traffic Control, and with the training given to pilots. Since trajectory evaluation for the GA is performed holistically, a wide class of objective functions can be optimized easily. Also, using the GA it is possible to compare the costs associated with

  7. Low profile, high load vertical rolling positioning stage

    DOEpatents

    Shu, Deming; Barraza, Juan

    1996-01-01

    A stage or support platform assembly for use in a synchrotron accurately positions equipment to be used in the beam line of the synchrotron. The support platform assembly includes an outer housing in which is disposed a lifting mechanism having a lifting platform or stage at its upper extremity on which the equipment is mounted. A worm gear assembly is located in the housing and is adapted to raise and lower a lifting shaft that is fixed to the lifting platform by an anti-binding connection. The lifting platform is moved vertically as the lifting shaft is moved vertically. The anti-binding connection prevents the shaft from rotating with respect to the platform, but does permit slight canting of the shaft with respect to the lifting platform so as to eliminate binding and wear due to possible tolerance mismatches. In order to ensure that the lifting mechanism does not move in a horizontal direction as it is moved vertically, at least three linear roller bearing assemblies are arranged around the outer-periphery of the lifting mechanism. One of the linear roller bearing assemblies can be adjusted so that the roller bearings apply a loading force against the lifting mechanism. Alternatively, a cam mechanism can be used to provide such a loading force.

  8. Vertical Profiles of Aerosol Volume from High Spectral Resolution Infrared Transmission Measurements: Results

    NASA Technical Reports Server (NTRS)

    Eldering, Annmarie; Kahn, Brian H.; Mills, Franklin P.; Irion, Fredrick W.; Steele, Helen M.; Gunson, Michael R.

    2004-01-01

    The high-resolution infrared absorption spectra of the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment are utilized to derive vertical profiles of sulfate aerosol volume density and extinction coefficient. Following the eruption of Mt. Pinatubo in June 1991, the ATMOS spectra obtained on three Space Shuttle missions (1992, 1993, and 1994) provide a unique opportunity to study the global stratospheric sulfate aerosol layer shortly after a major volcanic eruption and periodically during the decay phase. Synthetic sulfate aerosol spectra are fit to the observed spectra, and a global fitting inversion routine is used to derive vertical profiles of sulfate aerosol volume density. Vertical profiles of sulfate aerosol volume density for the three missions over portions of the globe are presented, with the peak in aerosol volume density occurring from as low as 10 km (polar latitudes) to as high as 20 km (subtropical latitudes). Derived aerosol volume density is as high as 2-3.5 (mu)m(exp 3) per cubic centimeter +/-10% in 1992, decreasing to 0.2-0.5 (mu)m(exp 3) per cubic centimeter +/-20% in 1994, in agreement with other experiments. Vertical extinction profiles derived from ATMOS are compared with profiles from Improved Stratospheric And Mesospheric Sounder (ISAMS) and Cryogenic Limb Array Etalon Spectrometer (CLAES) that coincide in space and time and show good general agreement. The uncertainty of the ATMOS vertical profiles is similar to CLAES and consistently smaller than ISAMS at similar altitudes.

  9. Flight Services and Aircraft Access: Active Flow Control Vertical Tail and Insect Accretion and Mitigation Flight Test

    NASA Technical Reports Server (NTRS)

    Whalen, Edward A.

    2016-01-01

    This document serves as the final report for the Flight Services and Aircraft Access task order NNL14AA57T as part of NASA Environmentally Responsible Aviation (ERA) Project ITD12A+. It includes descriptions of flight test preparations and execution for the Active Flow Control (AFC) Vertical Tail and Insect Accretion and Mitigation (IAM) experiments conducted on the 757 ecoDemonstrator. For the AFC Vertical Tail, this is the culmination of efforts under two task orders. The task order was managed by Boeing Research & Technology and executed by an enterprise-wide Boeing team that included Boeing Research & Technology, Boeing Commercial Airplanes, Boeing Defense and Space and Boeing Test and Evaluation. Boeing BR&T in St. Louis was responsible for overall Boeing project management and coordination with NASA. The 757 flight test asset was provided and managed by the BCA ecoDemonstrator Program, in partnership with Stifel Aircraft Leasing and the TUI Group. With this report, all of the required deliverables related to management of this task order have been met and delivered to NASA as summarized in Table 1. In addition, this task order is part of a broader collaboration between NASA and Boeing.

  10. Low-Speed Wind-Tunnel Tests of a Pilotless Aircraft Having Horizontal and Vertical Wings and Cruciform Tail

    NASA Technical Reports Server (NTRS)

    Mastrocola, N; Assadourian, A

    1947-01-01

    Low-speed tests of a pilotless aircraft were conducted in the Langley propeller-research tunnel to provide information for the estimation of the longitudinal stability and. control, to measure the aileron effectiveness, and to calibrate the radome and the Machmeter pitot-static orifices. It was found that the model possessed a stEb.le variation of elevator angle required for trim throughout the speed range at the design angle of attack. A comparison of the airplane with and without JATO units and with an alternate rocket booster showed that a large loss in longitudinal stability and control resulting from the addition of the rocket booster to the aircraft was sufficient to make the rocket-booster assembly unsatisfactory as an alternate for the JATO units. Reversal of the aileron effectiveness was evident at positive deflections of the vertical wing flap indicating that the roll-stabilization system would produce roiling moments in a tight right turn contrary to its design purpose. Vertical-wing-flap deflections caused large errors in the static-pressure reading obtained by the original static-tube installation. A practical installation point on the fuselage was located which should yield reliable measurement of the free-stream static pressure.

  11. Use of temperature profiles beneath streams to determine rates of vertical ground-water flow and vertical hydraulic conductivity

    USGS Publications Warehouse

    Lapham, Wayne W.

    1989-01-01

    The use of temperature profiles beneath streams to determine rates of vertical ground-water flow and effective vertical hydraulic conductivity of sediments was evaluated at three field sites by use of a model that numerically solves the partial differential equation governing simultaneous vertical flow of fluid and heat in the Earth. The field sites are located in Hardwick and New Braintree, Mass., and in Dover, N.J. In New England, stream temperature varies from about 0 to 25 ?C (degrees Celsius) during the year. This stream-temperature fluctuation causes ground-water temperatures beneath streams to fluctuate by more than 0.1 ?C during a year to a depth of about 35 ft (feet) in fine-grained sediments and to a depth of about 50 ft in coarse-grained sediments, if ground-water velocity is 0 ft/d (foot per day). Upward flow decreases the depth affected by stream-temperature fluctuation, and downward flow increases the depth. At the site in Hardwick, Mass., ground-water flow was upward at a rate of less than 0.01 ft/d. The maximum effective vertical hydraulic conductivity of the sediments underlying this site is 0.1 ft/d. Ground-water velocities determined at three locations at the site in New Braintree, Mass., where ground water discharges naturally from the underlying aquifer to the Ware River, ranged from 0.10 to 0.20 ft/d upward. The effective vertical hydraulic conductivity of the sediments underlying this site ranged from 2.4 to 17.1 ft/d. Ground-water velocities determined at three locations at the Dover, N.J., site, where infiltration from the Rockaway River into the underlying sediments occurs because of pumping, were 1.5 ft/d downward. The effective vertical hydraulic conductivity of the sediments underlying this site ranged from 2.2 to 2.5 ft/d. Independent estimates of velocity at two of the three sites are in general agreement with the velocities determined using temperature profiles. The estimates of velocities and conductivities derived from the

  12. Low profile optical system for an aircraft beacon.

    PubMed

    Schwartz, A H

    1971-02-01

    An optical system producing an annular cone of radiation from a point source using a low profile front lens is shown to have application as a beacon for high speed vehicles. The system comprises a high pressure short are light source with axial electrodes and integral collector, a conical reflector, and a divergent meniscus lens that has low protrusion over the surface of the vehicle. The system has minimal drag, and the radiation is distributed in directions close to the plane perpendicular to the optical axis. The influences of various parameters such as lens camber, lens aperture, source size, collector shape, collection efficiency, and beam divergence are discussed. A prototype was built at Eimae Division of Varian using a xenon short arc lamp with metal ceramic structure and integral collector.

  13. How Well Do State-of-the-Art Techniques Measuring the Vertical Profile of Tropospheric Aerosol Extinction Compare?

    SciTech Connect

    Schmid, Beat; Ferrare, Richard; Flynn, Connor M.; Elleman, Robert; Covert, David; Strawa, A.; Welton, E J.; Turner, David D.; Jonsson, Haf; Redemann, Jens; Eilers, J.; Ricci, K.; Hallar, A. G.; Clayton, M. B.; Michalsky, Joseph J.; Smirnov, A.; Holben, B. N.; Barnard, James C.

    2006-02-01

    The recent U.S. Department of Energy Atmospheric Radiation Measurements (ARM) Aerosol Intensive Observation Period (AIOP, May 2003) yielded one of the best measurement sets obtained to-date to assess our ability to measure the vertical profile of ambient aerosol extinction. During one month, a heavily instrumented aircraft with well characterized aerosol sampling ability carrying well proven and new aerosol instrumentation, devoted most of the 60 available flight hours to flying vertical profiles over the heavily instrumented ARM Southern Great Plains (SGP) Climate Research Facility (CRF). This allowed us to compare vertical extinction profiles obtained from 6 different instruments: airborne Sun photometer, airborne nephelometer/absorption photometer, airborne cavity ring-down system, ground-based Raman lidar and two ground-based elastic backscatter lidars. We find the in situ measurements to be biased low (2 - 4 Mm 1 equivalent to 12-17% in the visible, or 45% in the near-infrared) when compared to airborne sunphotometer extinction. On the other hand, we find that with respect to AATS-14, the lidar ?ep(?) are biased high. Bias differences are 0.004 Km-1 (13%) and 0.007 Km-1 (24%) for the two elastic back-scatter lidars (MPLARM and MPLNET, ? = 523 nm) and 0.029 Km-1 (54%) for the Raman lidar (? = 355 nm). An unnoticed loss of sensitivity of the Raman lidar had occurred leading up to AIOP and we expect better agreement from the recently restored system. Looking at the collective results from six field campaigns conducted since 1996, airborne in situ measurements of extinction tend to be biased slightly low (17% at visible wavelengths) when compared to airborne sunphotometer extinction. On the other hand, extinction derived from lidars tend to have no or positive biases. We conclude that the error associated with measuring the tropospheric vertical profile of the ambient aerosol extinction with current state-of-the art instrumentation is 15-20% at visible wavelengths

  14. How Well do State-of-the-Art Techniques Measuring the Vertical Profile of Tropospheric Aerosol Extinction Compare?

    NASA Technical Reports Server (NTRS)

    Schmid, B.; Ferrare, R.; Flynn, C.; Elleman, R.; Covert, D.; Strawa, A.; Welton, E.; Turner, D.; Jonsson, H.; Redemann, J.; Eilers, J.; Ricci, K.; Hallar, A. G.; Clayton, M.; Michalsky, J.; Smirnov, A.; Holben, B.; Barnard, J.

    2006-01-01

    The recent Department of Energy Atmospheric Radiation Measurement (ARM) Aerosol Intensive Operations Period (AIOP, May 2003) yielded one of the best measurement sets obtained to date to assess our ability to measure the vertical profile of ambient aerosol extinction sigma(ep)(lambda) in the lower troposphere. During one month, a heavily instrumented aircraft with well-characterized aerosol sampling ability carrying well-proven and new aerosol instrumentation devoted most of the 60 available flight hours to flying vertical profiles over the heavily instrumented ARM Southern Great Plains (SGP) Climate Research Facility (CRF). This allowed us to compare vertical extinction profiles obtained from six different instruments: airborne Sun photometer (AATS-14), airborne nephelometer/absorption photometer, airborne cavity ring-down system, groundbased Raman lidar, and two ground-based elastic backscatter lidars. We find the in situ measured sigma(ep)(lambda) to be lower than the AATS-14 derived values. Bias differences are 0.002-0.004 Km!1 equivalent to 13-17% in the visible, or 45% in the near-infrared. On the other hand, we find that with respect to AATS-14, the lidar sigma(ep)(lambda) are higher: Bias differences are 0.004 Km(-1) (13%) and 0.007 Km(-1) (24%) for the two elastic backscatter lidars (MPLNET and MPLARM, lambda = 523 nm) and 0.029 Km(-1) (54%) for the Raman lidar (lambda = 355 nm). An unnoticed loss of sensitivity of the Raman lidar had occurred leading up to AIOP, and we expect better agreement from the recently restored system. Looking at the collective results from six field campaigns conducted since 1996, airborne in situ measurements of sigma(ep)(lambda) tend to be biased slightly low (17% at visible wavelengths) when compared to airborne Sun photometer sigma(ep)(lambda). On the other hand, sigma(ep)(lambda) values derived from lidars tend to have no or positive biases. From the bias differences we conclude that the typical systematic error associated

  15. Modeling The Vertical Profile Of Tholin Particles In The Atmosphere Of Titan

    NASA Astrophysics Data System (ADS)

    Liang, Mao-Chang; Li, C.; Zhang, X.; Yung, Y.

    2012-10-01

    Detailed vertical profiles of minor species from 100 to 1000 km and of tholins above 300 km have recently been deduced from Cassini observations. To match the observed profiles of three major C2-hydrocarbons (C2H2, C2H4, and C2H6), modifications to the existing kinetics and vertical transport are needed. The latter plays a crucial role. Incorporating these modifications and a parameterized aerosol formation pathway into a chemistry-diffusion model, we could explain the observed tholin profile made by the Cassini/UVIS instrument. Processes that affect the profile are (1) aerosol production, (2) aerosol coagulation, and (3) dynamical transport. Sensitivity of the resulting tholin profile to the processes is examined and discussed.

  16. Vertical Lift Aircraft Design Conference, San Francisco, CA, Jan. 17-19, 1990, Proceedings

    SciTech Connect

    Not Available

    1990-01-01

    Topics presented include an overview of the NASA High Speed Rotorcraft Technology Development Program, propulsion system design for supersonic STOVL aircraft, NASA studies on hot gas ingestion and ground effects on STOVL aircraft, and the V/STOL transport concepts for special operations. Also presented are fault-tolerant architecture for a fly-by-light flight control computer, the servo flap in an advanced rotor control system, the high-speed rotorcraft V/STOL, and the improvement to interactive two-dimensional rotor section design. Also contributed are the experimental investigation of wingtip aerodynamic loading, the performance of an optimized rotor blade at off-design flight conditions, an unmanned air vehicle concept with tipjet drive, and AH-64A Apache hydraulic flight control system survivability design concepts.

  17. Aircraft observations of the vertical structure of stratiform precipitation relevant to microwave radiative transfer

    NASA Technical Reports Server (NTRS)

    Chang, A. T. C.; Barnes, A.; Glass, M.; Kakar, R.; Wilheit, T. T.

    1993-01-01

    The retrieval of rainfall intensity over the oceans from passive microwave observations is based on a radiative transfer model. Direct rainfall observations of oceanic rainfall are virtually nonexistent making validation of the retrievals extremely difficult. Observations of the model assumptions provide an alternative approach for improving and developing confidence in the rainfall retrievals. In the winter of 1983, the NASA CV-990 aircraft was equipped with a payload suitable for examining several of the model assumptions. The payload included microwave and infrared radiometers, mirror hygrometers, temperature probes, and PMS probes. On two occasions the aircraft ascended on a spiral track through stratiform precipitation providing an opportunity to study the atmospheric parameters. The assumptions concerning liquid hydrometeors, water vapor, lapse rate, and nonprecipitating clouds were studied. Model assumptions seem to be supported by these observations.

  18. Aircraft observations of the vertical structure of stratiform precipitation relevant to microwave radiative transfer

    SciTech Connect

    Chang, A.T.C. ); Barnes, A.; Glass, M. ); Kakar, R. ); Wilheit, T.T. )

    1993-06-01

    The retrieval of rainfall intensity over the oceans from passive microwave observations is based on a radiative transfer model. direct rainfall observations of oceanic rainfall are virtually nonexistent making validation of the retrievals extremely difficult. Observations of the model assumptions provide an alternative approach for improving and developing confidence in the rainfall retrievals. In the winter of 1983, the NASA CV-990 aircraft was equipped with a payload suitable for examining several of the model assumptions. The payload included microwave and infrared radiometers, mirror hygrometers, temperature probes, and PMS probes. On two occasions the aircraft ascended on a spiral track through stratiform precipitation providing an opportunity to study the atmospheric parameters. The assumptions concerning liquid hydrometeors, water vapor, lapse rate, and nonprecipitating clouds were studied. Model assumptions seem to be supported by these observations. 23 refs., 7 figs.

  19. Measurements of Vertical Profiles of Turbulence, Temperature, Ozone, Aerosols, and BrO over Sea Ice and Tundra Snowpack during BROMEX

    NASA Astrophysics Data System (ADS)

    Shepson, P.; Caulton, D.; Cambaliza, M. L.; Dhaniyala, S.; Fuentes, J. D.; General, S.; Halfacre, J. W.; Nghiem, S. V.; Perez Perez, L.; Peterson, P. K.; Platt, U.; Pohler, D.; Pratt, K. A.; Simpson, W. R.; Stirm, B.; Walsh, S. J.; Zielcke, J.

    2012-12-01

    During the BROMEX field campaign of March 2012, we conducted measurements of boundary layer structure, ozone, BrO and aerosol, from a light, twin-engine aircraft during eleven flights originating from Barrow, AK. Flights were conducted over the sea ice in the Beaufort and Chukchi Seas, and over the tundra from Barrow to the Brooks Range, with vertical profiles covering altitudes from the surface to 3.5km in the free troposphere. Flights over the course of one month allowed a variety of sea ice conditions, including open water, nilas, first year sea ice, and frost flowers, to be examined over the Chukchi Sea. Atmospheric turbulence was measured using a calibrated turbulence probe, which will enable characterization of both the structure and turbulence of the Arctic boundary layer. Ozone was measured using a 2B UV absorption instrument. A GRIMM optical particle counter was used to measure 0.25-4 μm sized aerosol particles. The MAX-DOAS instrument enabled measurements of BrO vertical profiles. The aircraft measurements can be used to connect the surface measurements of ozone and BrO from the "Icelander" buoys, and the surface sites at Barrow, with those measured on the aircraft. Here we will discuss the spatial variability/coherence in these data. A major question that will be addressed using these data is the extent to which bromine is activated through reactions at the snowpack/ice surface versus the surface of aerosols. Here we will present a preliminary analysis of the relationships between snow/ice surface types, aerosol size-resolved number concentrations, and the vertical profiles of ozone and BrO.

  20. Influence of particles shape on the vertical profile of blowing snow concentration

    NASA Astrophysics Data System (ADS)

    Vionnet, Vincent; Trouvilliez, Alexandre; Naaim-Bouvet, Florence; Guyomarc'h, Gilbert

    2013-04-01

    In alpine regions, blowing snow events strongly influence the temporal and spatial evolution of the snow cover throughout the winter season. In Antarctica, blowing snow is an essential surface mass balance process and plays a non-negligible role in the annual accumulation. The vertical profile of blowing snow concentration determines the quantity of snow transported in turbulent suspension. A power law is often used to represent this vertical profile. It serves as an analytical solution representing an equilibrium between vertical turbulent diffusion and gravitational settling. In this work, we study how the exponent of the power law depends on the type of transported particles. Vertical profiles of blowing snow concentration have been collected at the experimental site of Col du Lac Blanc (French Alps) in 2011 and 2012 and near the research station of Cap Prud'homme (Antarctica) in 2010 and 2011. We used mechanical gauges (butterfly nets) and optical devices (Snow Particles Counters). Profiles collected during blowing snow events with precipitation have been corrected to account for the contribution of snowfall. Results show that profiles collected during blowing snow without snowfall differ from the corrected profiles collected during snowfall. At a given wind speed, particles transported during snowfall have a lower settling velocity than particles transported without snowfall. This difference confirms earlier observations (Takahashi, 1985) and can be explained by the change of drag coefficient between dendritic and rounded particles. This difference pertains several hours after the end of the snowfall illustrating the fragmentation of snow grains during blowing snow events.

  1. CALIBRATION OF A VERTICAL-SCAN LONG TRACE PROFILER AT MSFC.

    SciTech Connect

    GUBAREV,M.; KESTER,T.; TAKACS,P.Z.

    2001-07-31

    The long trace profiler (LTP) is the instrument of choice for the surface figure measurement of grazing incidence mirrors. The modification of conventional LTP, the vertical-scan LTP, capable of measuring the surface figure of replicated shell mirrors is now in operation at Marshall Space Flight Center. A few sources of systematic error for vertical-scan LTP are discussed. Status of systematic error reduction is reported.

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

    NASA Technical Reports Server (NTRS)

    Reehorst, Andrew L.

    2001-01-01

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

  3. Midlatitude sporadic-E layers and vertical metallic ion drift profiles

    NASA Astrophysics Data System (ADS)

    Royrvik, O.

    1983-02-01

    An investigation of the relationship between the occurrence of midlatitude sporadic-E-layers and convergent points in the ion drift profiles has been made using the 430 MHz incoherent scatter radar at the Arecibo Observatory. Electron concentration profiles were obtained using a 13 baud Barker coded pulse yielding 600 m range resolution, while a 5-pulse sequence with 2.4 km range resolution was used to obtain line-of-sight ion drift velocities. With some exceptions, observed sporadic-E layers occur near convergent points in the vertical metallic ion drift profile, and vertical motions of these layers follow the vertical motions of the convergent point. A sudden increase in the altitude of a sporadic-E layer has been observed. This is attributed to the disappearance of the convergent point, releasing the layer, followed by an ascent of the layer to the closest overlying convergent point.

  4. Calibration of the total carbon column observing network using aircraft profile data

    NASA Astrophysics Data System (ADS)

    Wunch, D.; Toon, G. C.; Wennberg, P. O.; Wofsy, S. C.; Stephens, B. B.; Fischer, M. L.; Uchino, O.; Abshire, J. B.; Bernath, P.; Biraud, S. C.; Blavier, J.-F. L.; Boone, C.; Bowman, K. P.; Browell, E. V.; Campos, T.; Connor, B. J.; Daube, B. C.; Deutscher, N. M.; Diao, M.; Elkins, J. W.; Gerbig, C.; Gottlieb, E.; Griffith, D. W. T.; Hurst, D. F.; Jiménez, R.; Keppel-Aleks, G.; Kort, E.; Macatangay, R.; Machida, T.; Matsueda, H.; Moore, F.; Morino, I.; Park, S.; Robinson, J.; Roehl, C. M.; Sawa, Y.; Sherlock, V.; Sweeney, C.; Tanaka, T.; Zondlo, M. A.

    2010-06-01

    The Total Carbon Column Observing Network (TCCON) produces precise measurements of the column average dry-air mole fractions of CO2, CO, CH4, N2O and H2O at a variety of sites worldwide. These observations rely on spectroscopic parameters that are not known with sufficient accuracy to compute total columns that can be used in combination with in situ measurements. The TCCON must therefore be calibrated to World Meteorological Organization (WMO) in situ trace gas measurement scales. We present a calibration of TCCON data using WMO-scale instrumentation aboard aircraft that measured profiles over four TCCON stations during 2008 and 2009. The aircraft campaigns are the Stratosphere-Troposphere Analyses of Regional Transport 2008 (START-08), which included a profile over the Park Falls site, the HIAPER Pole-to-Pole Observations (HIPPO-1) campaign, which included profiles over the Lamont and Lauder sites, a series of Learjet profiles over the Lamont site, and a Beechcraft King Air profile over the Tsukuba site. These calibrations are compared with similar observations made during the INTEX-NA (2004), COBRA-ME (2004) and TWP-ICE (2006) campaigns. A single, global calibration factor for each gas accurately captures the TCCON total column data within error.

  5. Calibration of the Total Carbon Column Observing Network using Aircraft Profile Data

    SciTech Connect

    Wunch, Debra; Toon, Geoffrey C.; Wennberg, Paul O.; Wofsy, Steven C.; Stephens, Britton B.; Fischer, Marc L.; Uchino, Osamu; Abshire, James B.; Bernath, Peter; Biraud, Sebastien C.; Blavier, Jean-Francois L.; Boone, Chris; Bowman, Kenneth P.; Browell, Edward V.; Campos, Teresa; Connor, Brian J.; Daube, Bruce C.; Deutscher, Nicholas M.; Diao, Minghui; Elkins, James W.; Gerbig, Christoph; Gottlieb, Elaine; Griffith, David W. T.; Hurst, Dale F.; Jimenez, Rodrigo; Keppel-Aleks, Gretchen; Kort, Eric; Macatangay, Ronald; Machida, Toshinobu; Matsueda, Hidekazu; Moore, Fred; Morino, Isamu; Park, Sunyoung; Robinson, John; Roehl, Coleen M.; Sawa, Yusuke; Sherlock, Vanessa; Sweeney, Colm; Tanaka, Tomoaki; Zondlo, Mark A.

    2010-03-26

    The Total Carbon Column Observing Network (TCCON) produces precise measurements of the column average dry-air mole fractions of CO{sub 2}, CO, CH{sub 4}, N{sub 2}O and H{sub 2}O at a variety of sites worldwide. These observations rely on spectroscopic parameters that are not known with sufficient accuracy to compute total columns that can be used in combination with in situ measure ments. The TCCON must therefore be calibrated to World Meteorological Organization (WMO) in situ trace gas measurement scales. We present a calibration of TCCON data using WMO-scale instrumentation aboard aircraft that measured profiles over four TCCON stations during 2008 and 2009. The aircraft campaigns are the Stratosphere-Troposphere Analyses of Regional Transport 2008 (START-08), which included a profile over the Park Falls site, the HIAPER Pole-to-Pole Observations (HIPPO-1) campaign, which included profiles over the Lamont and Lauder sites, a series of Learjet profiles over the Lamont site, and a Beechcraft King Air profile over the Tsukuba site. These calibrations are compared with similar observations made during the INTEX-NA (2004), COBRA-ME (2004) and TWP-ICE (2006) campaigns. A single, global calibration factor for each gas accurately captures the TCCON total column data within error.

  6. Retrieval of Vertical Ozone Profile Using Satellite Solar Occultation Method and Tests of its Sensitivity

    NASA Astrophysics Data System (ADS)

    Cho, Hi-Ku; Yoon, Young-Jun; Park, Jae H.; Lee, Kwang Mok; Tatsuya, Yokota

    1998-06-01

    Recently measurements of atmospheric trace gases from satellite are vigorous. So the development of its data processing algorithm is important. In this study, retrieval of vertical ozone profile from the atmospheric transmittance measured by satellite solar occultation method and its sensitivity to temperature and pressure are investigated. The measured transmittance from satellite is assumed to be given by the limb path transmittance simulated using annual averaged Umkehr data for Seoul. The limb path transmittance between wavelengths 9.89micro m and 10.02micro m is simulated with respect to tangent heights using the ozone data of HALOE SIDS(Hallogen Occultation Experiment Simulated Instrument Data Set) as an initial profile. Other input data such as pressure and temperature are also from HALOE SIDS. Vertical ozone profile is correctly retrieved from the measured transmittance by onion-peeling method from 50km to 11km tangent heights with the vertical resolution of 3km. The bias error of +/- 0.001 in measured transmittance, the forced error of +/- 3K in each layer temperature, and the forced +/- 3% error in each layer pressure are assumed for sensitivity tests. These errors are based on the ADEOS/ILAS error limitation. The error in ozone amount ranges from -6.5% to +6.9% due to transmittance error, from -9.5% to +10.5% due to temperature error, and from -5.1% to +5.4% due to pressure error, respectively. The present study suggests that accurate vertical ozone profile can be retrieved from satellite solar occultation method. Accuracy of vertical temperature profile is especially important in the retrieval of vertical ozone profile.

  7. An analysis of the vertical structure equation for arbitrary thermal profiles

    NASA Technical Reports Server (NTRS)

    Cohn, Stephen E.; Dee, Dick P.

    1987-01-01

    The vertical structure equation is a singular Sturm-Liouville problem whose eigenfunctions describe the vertical dependence of the normal modes of the primitive equations linearized about a given thermal profile. The eigenvalues give the equivalent depths of the modes. The spectrum of the vertical structure equation and the appropriateness of various upper boundary conditions, both for arbitrary thermal profiles were studied. The results depend critically upon whether or not the thermal profile is such that the basic state atmosphere is bounded. In the case of a bounded atmosphere it is shown that the spectrum is always totally discrete, regardless of details of the thermal profile. For the barotropic equivalent depth, which corresponds to the lowest eigen value, upper and lower bounds which depend only on the surface temperature and the atmosphere height were obtained. All eigenfunctions are bounded, but always have unbounded first derivatives. It was proved that the commonly invoked upper boundary condition that vertical velocity must vanish as pressure tends to zero, as well as a number of alternative conditions, is well posed. It was concluded that the vertical structure equation always has a totally discrete spectrum under the assumptions implicit in the primitive equations.

  8. Measurements of the vertical profile of water vapor abundance in the Martian atmosphere from Mars Observer

    NASA Technical Reports Server (NTRS)

    Schofield, J. T.; Mccleese, Daniel J.

    1988-01-01

    An analysis is presented of the Pressure Modulator Infrared Radiometer (PMIRR) capabilities along with how the vertical profiles of water vapor will be obtained. The PMIRR will employ filter and pressure modulation radiometry using nine spectral channels, in both limb scanning and nadir sounding modes, to obtain daily, global maps of temperature, dust extinction, condensate extinction, and water vapor mixing ratio profiles as a function of pressure to half scale height or 5 km vertical resolution. Surface thermal properties will also be mapped, and the polar radiactive balance will be monitored.

  9. Generation of optimum vertical profiles for an advanced flight management system

    NASA Technical Reports Server (NTRS)

    Sorensen, J. A.; Waters, M. H.

    1981-01-01

    Algorithms for generating minimum fuel or minimum cost vertical profiles are derived and examined. The option for fixing the time of flight is included in the concepts developed. These algorithms form the basis for the design of an advanced on-board flight management system. The variations in the optimum vertical profiles (resulting from these concepts) due to variations in wind, takeoff mass, and range-to-destination are presented. Fuel savings due to optimum climb, free cruise altitude, and absorbing delays enroute are examined.

  10. Interpretation of combined wind profiler and aircraft-measured tropospheric winds and clear air turbulence

    NASA Technical Reports Server (NTRS)

    Thomson, D. W.; Syrett, William J.; Fairall, C. W.

    1991-01-01

    In the first experiment, it was found that wind profilers are far better suited for the detailed examination of jet stream structure than are weather balloons. The combination of good vertical resolution with not previously obtained temporal resolution reveals structural details not seen before. Development of probability-derived shear values appears possible. A good correlation between pilot reports of turbulence and wind shear was found. In the second experiment, hourly measurements of wind speed and direction obtained using two wind profiling Doppler radars during two prolonged jet stream occurrences over western Pennsylvania were analyzed. In particular, the time-variant characteristics of derived shear profiles were examined. Profiler data dropouts were studied in an attempt to determine possible reasons for the apparently reduced performance of profiling radar operating beneath a jet stream. Richardson number and wind shear statistics were examined along with pilot reports of turbulence in the vicinity of the profiler.

  11. Comparison of glyoxal, BrO, and IO vertical profiles derived from both ground-based and airborne MAX-DOAS measurements

    NASA Astrophysics Data System (ADS)

    Coburn, Sean; Volkamer, Rainer; Baidar, Sunil; Dix, Barbara; Koenig, Theodore; Ortega, Ivan; Sinreich, Roman; van Roozendael, Michel; Hendrick, Francois; Kinnison, Doug

    2015-04-01

    The information content of ground-based MAX-DOAS retrievals is assessed by collocated aircraft measurements for a ship MAX-DOAS setup over the Eastern tropical Pacific Ocean (TORERO RF17), and a mountain-top MAX-DOAS setup at Mauna Loa Observatory, Hawaii (CONTRAST RF17). During both case studies the CU airborne MAX-DOAS (AMAX-DOAS) instrument aboard the NSF/NCAR GV aircraft measured profiles of glyoxal, BrO, and IO with 12-20 degrees of freedom and up to 500 m vertical resolution. The TORERO field campaign took place in 2012, while CONTRAST in 2014; both campaigns covered the months of January and February. Additional measurements aboard the aircraft helped to provide information/validation of the AMAX-DOAS derived profiles, such as in-situ water vapor from the Vertical-Cavity Surface-Emitting Laser hygrometer (VCSEL), in-situ hydrocarbon measurements from the Trace Organic Gas Analyzer (TOGA), and aerosol information constrained by the Ultra High Sensitivity Aerosol Spectrometer (UHSAS). The AMAX-DOAS profiles are compared with ground-based MAX-DOAS inversions. The latter explores the effect of using either the measured differential slant column density (dSCD) or SCD as input to the optimal estimation inversion, where SCD = dSCD + SCD_ref. SCD_ref is the residual column amount of the trace gas contained within the reference spectrum. For the AMAX-DOAS data, the values of SCD_ref were actively minimized, while SCD_ref is usually unknown for ground-based MAX-DOAS retrievals. In absence of independent measurements to constrain SCD_ref, the current state-of-the-art with ground-based MAX-DOAS applications is to use dSCDs as input to the inversion. Here we assess the effect of uncertain SCD_ref for ground-based MAX-DOAS profiles in form of a sensitivity study. Additionally for the ground-based data, different methods are compared for the determination of SCD_ref: 1) the collocated aircraft profiles described above present the opportunity to forward calculate the SCD

  12. Transport of magnetic flux and the vertical structure of accretion discs - II. Vertical profile of the diffusion coefficients

    NASA Astrophysics Data System (ADS)

    Guilet, Jérôme; Ogilvie, Gordon I.

    2013-04-01

    We investigate the radial transport of magnetic flux in a thin accretion disc, the turbulence being modelled by effective diffusion coefficients (viscosity and resistivity). Both turbulent diffusion and advection by the accretion flow contribute to flux transport, and they are likely to act in opposition. We study the consequences of the vertical variation of the diffusion coefficients, due to a varying strength of the turbulence. For this purpose, we consider three different vertical profiles of these coefficients. The first one is aimed at mimicking the turbulent stress profile observed in numerical simulations of magnetohydrodynamic turbulence in stratified discs. This enables us to confirm the robustness of the main result of Paper I obtained for uniform diffusion coefficients that, for weak magnetic fields, the contribution of the accretion flow to the transport velocity of magnetic flux is much larger than the transport velocity of mass. We then consider the presence of a dead zone around the equatorial plane where the physical resistivity is high while the turbulent viscosity is low. We find that it amplifies the previous effect: weak magnetic fields can be advected orders of magnitude faster than mass, for dead zones with a large vertical extension. The ratio of advection to diffusion, determining the maximum inclination of the field at the surface of the disc, is however not much affected. Finally, we study the effect of a non-turbulent layer at the surface of the disc, which has been suggested as a way to reduce the diffusion of the magnetic flux. We find that the reduction of the diffusion requires the conducting layer to extend below the height at which the magnetic pressure equals the thermal pressure. As a consequence, if the absence of turbulence is caused by the large-scale magnetic field, the highly conducting layer is inefficient at reducing the diffusion.

  13. VERTICAL MIXING AND CHEMISTRY OVER AN ARID URBAN SITE: FIRST RESULTS FROM AIRCRAFT OBSERVATIONS MADE DURING THE PHOENIX SUNRISE CAMPAIGN.

    SciTech Connect

    BERKOWITZ,C.M.; SPRINGSTON,S.R.; DORAN,J.C.; FAST,J.D.

    2002-01-13

    The role of boundary layer mixing is increasingly recognized as an important factor in determining the concentrations of ozone and other trace gases near the surface. While the concentrations at the surface can vary widely due to horizontal transport of chemical plumes, the boundary layer is also characterized by turbulence that follows a diurnal cycle in height and intensity. Surface oxidant concentrations can therefore undergo significant changes even in the absence of photochemistry. A central goal of the Phoenix 2001 Field Campaign was to study vertical mixing with the onset of convection and to quantify the effect of this mixing on chemistry within an urban boundary layer. As part of this study, a series of low altitude aircraft sampling flights were made over the Greater Phoenix area between June 16-30, 2001. The resulting observations, in conjunction with a series of surface measurements and meteorological observations, are being used to study the vertical transport and reactivity of ozone and ozone-precursors shortly after sunrise. Additional details of this campaign are given in Doran, et al. (2002). It was anticipated that turbulence over Phoenix at night would be suppressed as a result of cooling of the boundary layer over the city. By sampling shortly after sunrise, we hoped to collect measurements above the residual nocturnal stable layer and to continue sampling through the developmental period of a convectively active boundary layer. We report here on the first analysis of these observations, made from a Gulstream-1 (G-1) aircraft operated by the U.S. Department of Energy.

  14. Conceptual design of high speed supersonic aircraft: A brief review on SR-71 (Blackbird) aircraft

    NASA Astrophysics Data System (ADS)

    Xue, Hui; Khawaja, H.; Moatamedi, M.

    2014-12-01

    The paper presents the conceptual design of high-speed supersonic aircraft. The study focuses on SR-71 (Blackbird) aircraft. The input to the conceptual design is a mission profile. Mission profile is a flight profile of the aircraft defined by the customer. This paper gives the SR-71 aircraft mission profile specified by US air force. Mission profile helps in defining the attributes the aircraft such as wing profile, vertical tail configuration, propulsion system, etc. Wing profile and vertical tail configurations have direct impact on lift, drag, stability, performance and maneuverability of the aircraft. A propulsion system directly influences the performance of the aircraft. By combining the wing profile and the propulsion system, two important parameters, known as wing loading and thrust to weight ratio can be calculated. In this work, conceptual design procedure given by D. P. Raymer (AIAA Educational Series) is applied to calculate wing loading and thrust to weight ratio. The calculated values are compared against the actual values of the SR-71 aircraft. Results indicates that the values are in agreement with the trend of developments in aviation.

  15. [Monitoring and analysis of vertical profile of atmospheric HONO, NO2 in boundary layer of Beijing].

    PubMed

    Zhu, Yan-Wu; Liu, Wen-Qing; Fang, Jing; Xie, Pin-Hua; Dou, Ke; Qin, Min; Si, Fu-Qi

    2011-04-01

    Based on the scanning differential optical absorption spectroscopy (DOAS) system, field measurement of vertical profiles of HONO and NO2 was performed continuously from Aug. 27, 2007 to Sep. 4, 2007 in Chaoyang District of Beijing, and their vertical profiles were analyzed. Based on the acquired data, the typical vertical variation characteristics of HONO, NO2 and the ratio HONO/NO2 were discussed, and the possible formation sources of HONO were studied. The results indicated that the decrease of HONO with height was faster than the decrease of NO2. The study found good correlation between NO2 and HONO, as well as between the ratio HONO/NO2 and vapor, respectively. Therefore, the authors' conclusion is that HONO was formed by heterogeneous conversion of NO2 on surfaces or near ground and then transported to higher altitudes. PMID:21714264

  16. Development of an angular scanning system for sensing vertical profiles of soil electrical conductivity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Apparent soil electrical conductivity (EC**a**) is typically mapped to define soil spatial variability within an agricultural field. Knowledge of the vertical variability of EC**a** is desired to define site-specific behavior of the soil profile. A Pneumatic Angular Scanning System (PASS) was develo...

  17. From the shape of the vertical profile of in vivo fluorescence to Chlorophyll-a concentration

    NASA Astrophysics Data System (ADS)

    Mignot, A.; Claustre, H.; D'Ortenzio, F.; Xing, X.; Poteau, A.; Ras, J.

    2011-04-01

    In vivo fluorescence of Chlorophyll-a (Chl-a) is a potentially useful property to study the vertical distribution of phytoplankton biomass. However the technique is presently not fully exploited as it should be, essentially because of the difficulties in converting the fluorescence signal into an accurate Chl-a concentration. These difficulties arise noticeably from natural variations in the Chl-a fluorescence relationship, which is under the control of community composition as well as of their nutrient and light status. As a consequence although vertical profiles of fluorescence are likely the most recorded biological property in the open ocean, the corresponding large databases are underexploited. Here with the aim to convert a fluorescence profile into a Chl-a concentration profile, we test the hypothesis that the Chl-a concentration can be gathered from the sole knowledge of the shape of the fluorescence profile. We analyze a large dataset from 18 oceanographic cruises conducted in case-1 waters from the highly stratified hyperoligotrophic waters (surface Chl-a = 0.02 mg m-3) of the South Pacific Gyre to the eutrophic waters of the Benguela upwelling (surface Chl-a = 32 mg m-3) and including the very deep mixed waters in the North Atlantic (Mixed Layer Depth = 690 m). This dataset encompasses more than 700 vertical profiles of Chl-a fluorescence as well as accurate estimations of Chl-a by High Performance Liquid Chromatography (HPLC). Two typical fluorescence profiles are identified, the uniform profile, characterized by a homogeneous layer roughly corresponding to the mixed layer, and the non-uniform profile, characterized by the presence of a Deep Chlorophyll Maximum. Using appropriate mathematical parameterizations, a fluorescence profile is subsequently represented by 3 or 5 shape parameters for uniform or non-uniform profiles, respectively. For both situations, an empirical model is developed to predict the "true" Chl-a concentration from these shape

  18. From the shape of the vertical profile of in vivo fluorescence to Chlorophyll-a concentration

    NASA Astrophysics Data System (ADS)

    Mignot, A.; Claustre, H.; D'Ortenzio, F.; Xing, X.; Poteau, A.; Ras, J.

    2011-08-01

    In vivo fluorescence of Chlorophyll-a (Chl-a) is a potentially useful property to study the vertical distribution of phytoplankton biomass. However the technique is presently not fully exploited as it should be, essentially because of the difficulties in converting the fluorescence signal into an accurate Chl-a concentration. These difficulties arise noticeably from natural variations in the Chl-a fluorescence relationship, which is under the control of community composition as well as of their nutrient and light status. As a consequence, although vertical profiles of fluorescence are likely the most recorded biological property in the open ocean, the corresponding large databases are underexploited. Here with the aim to convert a fluorescence profile into a Chl-a concentration profile, we test the hypothesis that the Chl-a concentration can be gathered from the sole knowledge of the shape of the fluorescence profile. We analyze a large dataset from 18 oceanographic cruises conducted in case-1 waters from the highly stratified hyperoligotrophic waters (surface Chl-a = 0.02 mg m-3) of the South Pacific Gyre to the eutrophic waters of the Benguela upwelling (surface Chl-a = 32 mg m-3) and including the very deep mixed waters in the North Atlantic (Mixed Layer Depth = 690 m). This dataset encompasses more than 700 vertical profiles of Chl-a fluorescence as well as accurate estimations of Chl-a by High Performance Liquid Chromatography (HPLC). Two typical fluorescence profiles are identified, the uniform profile, characterized by a homogeneous layer roughly corresponding to the mixed layer, and the non-uniform profile, characterized by the presence of a Deep Chlorophyll Maximum. Using appropriate mathematical parameterizations, a fluorescence profile is subsequently represented by 3 or 5 shape parameters for uniform or non-uniform profiles, respectively. For both situations, an empirical model is developed to predict the "true" Chl-a concentration from these shape

  19. Coarse-fine vertical scanning based optical profiler for structured surface measurement with large step height

    NASA Astrophysics Data System (ADS)

    Zheng, Yi; Liu, Xiaojun; Lei, Zili; Li, Qian; Yang, Xiao; Chen, Liangzhou; Lu, Wenlong

    2015-02-01

    White light interference (WLI) optical profiler had been used widely for structured surface measurement. To achieve high measuring accuracy, piezoelectric ceramic (PZT) was usually used as the vertical scanning unit, which was normally less than 100um and only for small range structured surface measurement. With the development of advanced manufacturing technology, precision structured surfaces with large step height were appearing. To satisfy the measurement requirements of this kind of precision structured surfaces, WLI optical profiler with large range had to be developed. In this paper, an optical profiler was proposed, in which a coarse-fine vertical scanning system was adopted to expand its measurement range to 10mm while its resolution still at nanometer level.

  20. CO2 vertical profile retrieval from ground-based IR atmospheric spectra

    NASA Astrophysics Data System (ADS)

    Khosravian, Kobra; Loehnert, Ulrich; Turner, David; Ebell, Kerstin

    2016-04-01

    CO2 vertical profile retrieval from ground-based IR atmospheric spectra In this study, we developed an algorithm for retrieving the CO2 vertical profile from atmospheric ground-based zenith spectra in the mid IR. Providing the CO2 profile from continuous (24h/day) ground-based spectra would be a great potential for studying the carbon cycle, the evaluation of satellite measurements or the assessment of numerical models, which forecast the near-surface CO2 flux. In order to retrieve the CO2 profile, we used observations of the Atmospheric Emitted Radiance Interferometer (AERI) that was installed at the JOYCE (Jülich ObservatorY for Cloud Evolution), Germany in 2012. AERI measures downwelling infrared radiances from 520 cm-1 (3.3 μm) to 3020 cm-1 (19 μm) with a spectral resolution of 1 cm-1 and a temporal resolution of 1 minute. In a first step, we performed sensitivity studies for finding the most-suited spectral bands with highest sensitivity to the mean column amount of CO2 volume mixing ratio (VMR). Then an algorithm, known as AERIoe (Turner and Löhnert 2014), was applied to retrieve the mean column amount of CO2 VMR using simulated radiances in clear sky cases. AERIoe is a variational retrieval algorithm to provide information on Temperature, humidity, trace gases and clouds. The simulated AERI radiances were generated by a line by line radiative transfer model (LBLRTM) using model temperature, humidity and CO2 profile. The retrieval results of mean column amount of CO2 VMR are in good agreement with the true ones. In addition to the mean column amount, we modified AERIoe to retrieve the CO2 vertical profile. First results reveal that there is more than 1 degree of freedom for CO2 profile. We will show results how the retrieval method is refined to optimally exploit the information on the CO2 profile contained in the AERI measurements.

  1. Development of a Climatology of Vertically Complete Wind Profiles from Doppler Radar Wind Profiler Systems

    NASA Technical Reports Server (NTRS)

    Barbre, Robert, Jr.

    2015-01-01

    Assessment of space vehicle loads and trajectories during design requires a large sample of wind profiles at the altitudes where winds affect the vehicle. Traditionally, this altitude region extends from near 8-14 km to address maximum dynamic pressure upon ascent into space, but some applications require knowledge of measured wind profiles at lower altitudes. Such applications include crew capsule pad abort and plume damage analyses. Two Doppler Radar Wind Profiler (DRWP) systems exist at the United States Air Force (USAF) Eastern Range and at the National Aeronautics and Space Administration's Kennedy Space Center. The 50-MHz DRWP provides wind profiles every 3-5 minutes from roughly 2.5-18.5 km, and five 915-MHz DRWPs provide wind profiles every 15 minutes from approximately 0.2-3.0 km. Archived wind profiles from all systems underwent rigorous quality control (QC) processes, and concurrent measurements from the QC'ed 50- and 915-MHz DRWP archives were spliced into individual profiles that extend from about 0.2-18.5 km. The archive contains combined profiles from April 2000 to December 2009, and thousands of profiles during each month are available for use by the launch vehicle community. This paper presents the details of the QC and splice methodology, as well as some attributes of the archive.

  2. Vertical and Spatial Profiling of Arctic Black Carbon on the North Slope of Alaska 2015: Comparison of Model and Observation

    NASA Astrophysics Data System (ADS)

    Sedlacek, A. J., III; Feng, Y.; Biraud, S.; Springston, S. R.

    2015-12-01

    One of the major issues confronting aerosol climate simulations of the Arctic and Antarctic Cryospheres is the lack of detailed data on the vertical and spatial distribution of aerosols with which to test these models. This is due, in part, to the inherent difficulty of conducting such measurements in extreme environments. One class of under measured radiative forcing agents in the Polar Region is the absorbing aerosol - black carbon and brown carbon. In particular, vertical profile information of BC is critical in reducing uncertainty in model assessment of aerosol radiative impact at high latitudes. During the summer of 2015, a Single-Particle Soot Photometer (SP2) was deployed aboard the Department of Energy (DOE) Gultstream-1 (G-1) aircraft to measure refractory BC (rBC) concentrations as part of the DOE-sponsored ACME-V (ARM Airborne Carbon Measurements) campaign. This campaign was conducted from June through to mid-September along the North Slope of Alaska and was punctuated by vertical profiling over 5 sites (Atquasuk, Barrow, Ivotuk, Oliktok, and Toolik). In addition, measurement of CO, CO2 and CH4were also taken to provide information on the spatial and seasonal differences in GHG sources and how these sources correlate with BC. Lastly, these aerosol and gas measurements provide an important dataset to assess the representativeness of ground sites at regional scales. Comparisons between observations and a global climate model (CAM5) simulations will be agumented with a discussion on the capability of the model to capture observed monthly mean profiles of BC and stratified aerosol layers. Additionally, the ability of the SP2 to partition rBC-containing particles into nascent or aged species allows an evaluation of how well the CAM5 model captures aging of long distant transported carbonaceous aerosols. Finally model sensitivity studies will be aso be presented that investigated the relative importance of the different emission sectors to the summer Arctic

  3. Experimental study of vertical stress profiles of a confined granular bed under static and dynamic conditions.

    PubMed

    Mandato, S; Cuq, B; Ruiz, T

    2012-07-01

    In a wet agglomeration process inside a low shear mixer, the blade function is to induce i) homogenization of the liquid sprayed on the powder surface and ii) a stress field able to transfer the mechanical energy at the particle scale. In this work we study the mechanical state of a confined powder bed through the analysis of stress distributions (by force measurements) in a rectangular cell in two cases: for a classical model powder (i.e. glass beads) and a complex powder (i.e. wheat semolina). Two types of vertical stress profiles are obtained according to the type of measurements carried out in the powder bed, either locally (at different positions in the cell) or globally (at the entire base). The global vertical stress profile follows Janssen's model and the local vertical stress profile highlights a critical length, identified as the percolation threshold of the force network, and a shielding length near the bottom, which is similar to an influence length of the side walls. In the context of wet agglomeration, the results allow to consider the role of the characteristic lengths in the mixing bowl under vertical mechanical solicitation. PMID:22772594

  4. Evaluation of the Rotational Throttle Interface for Converting Aircraft Utilizing the NASA Ames Vertical Motion Simulator

    NASA Technical Reports Server (NTRS)

    Rozovski, David; Theodore, Colin R.

    2011-01-01

    An experiment was conducted to compare a conventional helicopter Thrust Control Lever (TCL) to the Rotational Throttle Interface (RTI) for tiltrotor aircraft. The RTI is designed to adjust its orientation to match the angle of the tiltrotor s nacelles. The underlying principle behind the design is to increase pilot awareness of the vehicle s configuration state (i.e. nacelle angle). Four test pilots flew multiple runs on seven different experimental courses. Three predominant effects were discovered in the testing of the RTI: 1. Unintentional binding along the control axis resulted in difficulties with precision power setting, 2. Confusion in which way to move the throttle grip was present during RTI transition modes, and 3. Pilots were not able to distinguish small angle differences during RTI transition. In this experiment the pilots were able to successfully perform all of the required tasks with both inceptors although the handling qualities ratings were slightly worse for the RTI partly due to unforeseen deficiencies in the design. Pilots did however report improved understanding of nacelle movement during transitions with the RTI.

  5. Inter-comparison of MAX-DOAS Retrieved Vertical Profiles of Aerosol Extinction, SO2 and NO2 in the Alberta Oil Sands with LIDAR Data and GEM-MACH Air Quality Model.

    NASA Astrophysics Data System (ADS)

    Davis, Zoe; Friess, Udo; Strawbridge, Kevin; Whiteway, James; Aggarwal, Monika; Makar, Paul; Li, Shao-Meng; O'Brien, Jason; Baray, Sabour; Schnitzler, Elijah; Olfert, Jason S.; Osthoff, Hans D.; Lobo, Akshay; McLaren, Robert

    2016-04-01

    Understanding industrial emissions of trace gas pollutants in the Alberta oil sands is essential to maintaining air quality standards and informing public policy. Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements of trace gases can improve knowledge of pollutant levels, vertical distribution and chemical transformation. During an intensive air measurement campaign to study emissions, transport, transformation and deposition of oil sands air pollutants from August to September of 2013, a MAX-DOAS instrument was deployed at a site north of Fort McMurray, Alberta to determine the vertical profiles of aerosol extinction, NO2 and SO2 through retrieval from the MAX-DOAS spectral measurements using an optimal estimation method. The large complement of data collected from multiple instruments deployed during this field campaign provides a unique opportunity to validate and characterize the performance of the MAX-DOAS vertical profile retrievals. Aerosol extinction profiles determined from two Light Detection and Ranging (LIDAR) instruments, one collocated and the other on a Twin Otter aircraft that flew over the site during the study, will be compared to the MAX-DOAS aerosol extinction profile retrievals. Vertical profiles of NO2 and SO2 retrieved from the MAX-DOAS measurements will be further compared with the composite vertical profiles measured from the flights of a second aircraft, the NRC-Convair 580, over the field site during the same measurement period. Finally, the MAX-DOAS retrieved tropospheric vertical column densities (VCDs) of SO2 and NO2 will be compared to the predicted VCDs from Environment and Climate Change Canada's Global Environmental Multi-scale - Modelling Air quality and Chemistry (GEM-MACH) air quality model over the grid cell containing the field site. Emission estimates of SO2 from the major oil mining facility Syncrude Mildred Lake using the MAX-DOAS VCD results, validated through the detailed characterization above

  6. Effects of control laws and relaxed static stability on vertical ride quality of flexible aircraft

    NASA Technical Reports Server (NTRS)

    Roberts, P. A.; Swaim, R. L.; Schmidt, D. K.; Hinsdale, A. J.

    1977-01-01

    State variable techniques are utilized to generate the RMS vertical load factors for the B-52H and B-1 bombers at low level, mission critical, cruise conditions. A ride quality index is proposed to provide meaningful comparisons between different controls or conditions. Ride quality is shown to be relatively invariant under various popular control laws. Handling quality variations are shown to be major contributors to ride quality variations on both vehicles. Relaxed static stability is artificially implemented on the study vehicles to investigate its effects on ride quality. The B-52H ride quality is generally degraded when handling characteristics are automatically restored by a feedback control to the original values from relaxed stability conditions. The B-1 airplane shows little ride quality sensitivity to the same analysis due to the small rigid body contribution to load factors at the flight condition investigated.

  7. First results of the PML monitor of atmospheric turbulence profile with high vertical resolution

    NASA Astrophysics Data System (ADS)

    Ziad, A.; Blary, F.; Borgnino, J.; Fanteï-Caujolle, Y.; Aristidi, E.; Martin, F.; Lantéri, H.; Douet, R.; Bondoux, E.; Mékarnia, D.

    2013-11-01

    Aims: Future extremely large telescopes will certainly be equipped with wide-field adaptive optics systems. The optimization of the performances of these techniques requires a precise specification of the different components of these AO systems. Most of these technical specifications are related to the atmospheric turbulence parameters, particularly the profile of the refractive index structure constant CN2(h). A new monitor called Profiler of Moon Limb (PML) for the extraction of the CN2(h) profile with high vertical resolution and its first results are presented. Methods: The PML instrument uses an optical method based on the observation of the Moon limb through two subapertures. The use of the lunar limb leads to a continuum of double stars allowing a scan of the whole atmosphere with high resolution in altitude. Results: The first prototype of the PML has been installed at Dome C in Antarctica and the first results of the PML are presented and compared to radio-sounding balloon profiles. In addition to the CN2(h) profile obtained with high vertical resolution, PML is also able to provide other atmospheric turbulence parameters such as the outer scale profile, the total seeing, and the isoplanatic and isopistonic angles.

  8. Vertical transport and removal of black carbon over East Asia in spring during the A-FORCE aircraft campaign

    NASA Astrophysics Data System (ADS)

    Oshima, N.; Koike, M.; Kondo, Y.; Nakamura, H.; Moteki, N.; Matsui, H.; Takegawa, N.; Kita, K.

    2014-12-01

    The Aerosol Radiative Forcing in East Asia (A-FORCE) aircraft campaign was conducted at 0-9 km in altitude over East Asia in March-April 2009 to investigate transport and removal processes of aerosols, their physical and chemical properties, and cloud microphysical properties in Asian outflow. In this study, mechanisms of vertical transport of black carbon (BC) aerosols and their three-dimensional transport pathways over East Asia in spring were examined through numerical simulations for the A-FORCE campaign using a modified version of the Community Multiscale Air Quality (CMAQ) modeling system. The simulations reproduced the spatial distributions of mass concentration of BC and its transport efficiency observed by the A-FORCE campaign reasonably well, including its vertical and latitudinal gradients and dependency on precipitation amount that air parcels experienced during the transport. During the A-FORCE period, two types of pronounced upward BC mass fluxes from the planetary boundary layer (PBL) to the free troposphere (FT) were found over northeastern and inland-southern China. Over northeastern China, cyclones with modest precipitation were the primary uplifting mechanism of BC. Over inland-southern China, both cumulus convection and orographic uplifting along the slopes of the Tibetan Plateau played important roles in the upward transport of BC, despite its efficient wet deposition due to a large amount of precipitation supported by an abundant moisture supply by the low-level southerlies. In addition to the midlatitude (35-45°N) eastward outflow within the PBL (21% BC removal by precipitation during transport), the uplifting of BC over northeastern and inland-southern China and the subsequent BC transport by the midlatitude lower tropospheric (50% BC removal) and subtropical (25-35°N) midtropospheric westerlies (67% BC removal), respectively, provided the major transport pathways for BC export from continental East Asia to the Pacific.

  9. Vertical transport mechanisms of black carbon over East Asia in spring during the A-FORCE aircraft campaign

    NASA Astrophysics Data System (ADS)

    Oshima, N.; Koike, M.; Kondo, Y.; Nakamura, H.; Moteki, N.; Matsui, H.; Takegawa, N.; Kita, K.

    2013-12-01

    of vertical transport of black carbon (BC) aerosols and their three-dimensional transport pathways over East Asia in spring were examined through numerical simulations for the Aerosol Radiative Forcing in East Asia (A-FORCE) aircraft campaign in March-April 2009 using a modified version of the Community Multiscale Air Quality (CMAQ) modeling system. The simulations reproduced the spatial distributions of mass concentration of BC and its transport efficiency observed by the A-FORCE campaign reasonably well, including its vertical and latitudinal gradients and dependency on precipitation amount that air parcels experienced during the transport. During the A-FORCE period, two types of pronounced upward BC mass fluxes from the planetary boundary layer (PBL) to the free troposphere were found over northeastern and inland-southern China. Over northeastern China, cyclones with modest precipitation were the primary uplifting mechanism of BC. Over inland-southern China, both cumulus convection and orographic uplifting along the slopes of the Tibetan Plateau played important roles in the upward transport of BC, despite its efficient wet deposition due to a large amount of precipitation supported by an abundant moisture supply by the low-level southerlies. In addition to the midlatitude (35-45°N) eastward outflow within the PBL (21% BC removal by precipitation during transport), the uplifting of BC over northeastern and inland-southern China and the subsequent BC transport by the midlatitude lower tropospheric (50% BC removal) and subtropical (25-35°N) midtropospheric westerlies (67% BC removal), respectively, provided the major transport pathways for BC export from continental East Asia to the Pacific.

  10. Non-homogeneous vertical distribution of methane over Indian region using surface, aircraft and satellite based data

    NASA Astrophysics Data System (ADS)

    Kavitha, M.; Nair, Prabha R.

    2016-09-01

    The upper tropospheric methane (UCH4) data from Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container (CARIBIC), the column average mixing ratio of methane (XCH4) from SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) and near-surface methane at two locations- Cape Rama, Goa, a Commonwealth Scientific Industrial Research Organization (CSIRO) network station and Ahmedabad (23.03°N; 72.45°E) were analysed to understand vertical inhomogenities in methane mixing ratio and the seasonal changes in the latitude sector 13°-24°N over India. XCH4 and UCH4 were found to follow more or less similar pattern over all the three latitude sectors, with the peak occurring in July-August, and minimum in late winter. The seasonal amplitude in XCH4 is less at low latitude sector (∼64 ppbv) compared to that of high latitudes (∼101 ppbv at 18°-22°N and 88 ppbv at 22°-24°N). On the other hand, the near surface methane shows opposite pattern peaking in winter attaining low in monsoon. During monsoon when methane sources are active at the surface, XCH4 > UCH4 and during other seasons UCH4 > XCH4 indicating presence of high altitude layers. This analysis revealed non-homogeneous distribution of methane in the troposphere indicative of stratified layers. The role of convective activity, boundary layer meteorology and long-range transport in controlling the seasonal changes in the vertical distribution of methane are examined in this study.

  11. Ground-based lidar and microwave radiometry synergy for high vertical resolution absolute humidity profiling

    NASA Astrophysics Data System (ADS)

    Barrera-Verdejo, María; Crewell, Susanne; Löhnert, Ulrich; Orlandi, Emiliano; Di Girolamo, Paolo

    2016-08-01

    Continuous monitoring of atmospheric humidity profiles is important for many applications, e.g., assessment of atmospheric stability and cloud formation. Nowadays there are a wide variety of ground-based sensors for atmospheric humidity profiling. Unfortunately there is no single instrument able to provide a measurement with complete vertical coverage, high vertical and temporal resolution and good performance under all weather conditions, simultaneously. For example, Raman lidar (RL) measurements can provide water vapor with a high vertical resolution, albeit with limited vertical coverage, due to sunlight contamination and the presence of clouds. Microwave radiometers (MWRs) receive water vapor information throughout the troposphere, though their vertical resolution is poor. In this work, we present an MWR and RL system synergy, which aims to overcome the specific sensor limitations. The retrieval algorithm combining these two instruments is an optimal estimation method (OEM), which allows for an uncertainty analysis of the retrieved profiles. The OEM combines measurements and a priori information, taking the uncertainty of both into account. The measurement vector consists of a set of MWR brightness temperatures and RL water vapor profiles. The method is applied to a 2-month field campaign around Jülich (Germany), focusing on clear sky periods. Different experiments are performed to analyze the improvements achieved via the synergy compared to the individual retrievals. When applying the combined retrieval, on average the theoretically determined absolute humidity uncertainty is reduced above the last usable lidar range by a factor of ˜ 2 with respect to the case where only RL measurements are used. The analysis in terms of degrees of freedom per signal reveal that most information is gained above the usable lidar range, especially important during daytime when the lidar vertical coverage is limited. The retrieved profiles are further evaluated using

  12. Observed changes in the vertical profile of stratopheric nitrous oxide at Thule, Greenland, February - March 1992

    NASA Technical Reports Server (NTRS)

    Emmons, Louisa K.; Reeves, John M.; Shindell, Drew T.; Dezafra, Robert L.

    1994-01-01

    Using a ground-based mm-wave spectrometer, we have observed stratospheric N2O over Thule, Greenland (76.3 N, 68.4 W) during late February and March, 1992. Vertical profiles of mixing ratio ranging from 16 to 50 km were recovered from molecular emission spectra. The profiles of early March show an abrupt increase in the lower-stratosphere N2O mixing ratio similar to the spring-to-summer change associated with the break up of the Antarctic polar vortex. This increase is correlated with changes in potential vorticity, air temperature, and ozone mixing ratio.

  13. GFIT2: an experimental algorithm for vertical profile retrieval from near-IR spectra

    NASA Astrophysics Data System (ADS)

    Connor, Brian J.; Sherlock, Vanessa; Toon, Geoff; Wunch, Debra; Wennberg, Paul O.

    2016-08-01

    An algorithm for retrieval of vertical profiles from ground-based spectra in the near IR is described and tested. Known as GFIT2, the algorithm is primarily intended for CO2, and is used exclusively for CO2 in this paper. Retrieval of CO2 vertical profiles from ground-based spectra is theoretically possible, would be very beneficial for carbon cycle studies and the validation of satellite measurements, and has been the focus of much research in recent years. GFIT2 is tested by application both to synthetic spectra and to measurements at two Total Carbon Column Observing Network (TCCON) sites. We demonstrate that there are approximately 3° of freedom for the CO2 profile, and the algorithm performs as expected on synthetic spectra. We show that the accuracy of retrievals of CO2 from measurements in the 1.61μ (6220 cm-1) spectral band is limited by small uncertainties in calculation of the atmospheric spectrum. We investigate several techniques to minimize the effect of these uncertainties in calculation of the spectrum. These techniques are somewhat effective but to date have not been demonstrated to produce CO2 profile retrievals with sufficient precision for applications to carbon dynamics. We finish by discussing ongoing research which may allow CO2 profile retrievals with sufficient accuracy to significantly improve the scientific value of the measurements from that achieved with column retrievals.

  14. Vertical dissipation profiles and the photosphere location in thin and slim accretion disks

    NASA Astrophysics Data System (ADS)

    Sadowski, A.; Abramowicz, M. A.; Bursa, M.; Kluźniak, W.; Różańska, A.; Straub, O.

    2009-07-01

    As several authors in the past, we calculate optically thick but geometrically thin (and slim) accretion disk models and perform a ray-tracing of photons in the Kerr geometry to calculate the observed disk continuum spectra. Previously, it was common practice to ray-trace photons assuming that they are emitted from the Kerr geometry equatorial plane, z = 0. We show that the continuum spectra calculated with this assumption differ from these calculated under the assumption that photons are emitted from the actual surface of the disc, z = H(r). This implies that a knowledge of the location of the thin disk effective photosphere is relevant for calculating the continuum emission. In this paper we investigate, in terms of a simple model, a possible influence of the (unknown, and therefore assumed ad hoc) vertical dissipation profiles on the vertical structure of the disk and thus on the location of the effective photosphere, and on the observed continuum spectra. For disks with moderate and high mass accretion rates (dot m > 0.01 dot m_C), we find that the photosphere location in the inner, radiation pressure dominated, disk region (where most of the radiation comes from) does not depend on the dissipation profile and therefore emerging disk spectra are insensitive to the choice of the dissipation function. For lower accretion rates, the photosphere location depends on the assumed vertical dissipation profile down to the disk inner edge, but the dependence is very weak and thus of minor importance. We conclude that the continuum spectra of optically thick accretion disks around black holes should be calculated with ray-tracing from the effective photosphere and that, fortunately, the choice of a particular vertical dissipation profile does not substantially influence the calculated emission.

  15. Characters analysis of the atmospheric turbulence vertical distribution profile over desert

    NASA Astrophysics Data System (ADS)

    Hu, Yuehong; Wang, Ke; Zhang, Zhi-gang; Feng, Shuang-lian; Wu, Ming

    2012-10-01

    The atmospheric refractive index structure constant is an important parameter of atmospheric turbulence intensity. It was measured using AZZ10 micro-thermalmeter over desert where is a little or no vegetation cover. The vertical profile were investigated by analysis of experimental data over desert with 0~30km height range. And structure characteristics of atmospheric turbulence were given. Results can supply technological support for laser engineering applications to select suitable testing time and time-interval.

  16. A New Airborne Lidar for Remote Sensing of Canopy Fluorescence and Vertical Profile

    NASA Astrophysics Data System (ADS)

    Ounis, A.; Bach, J.; Mahjoub, A.; Daumard, F.; Moya, I.; Goulas, Y.

    2016-06-01

    We report the development of a new lidar system for airborne remote sensing of chlorophyll fluorescence (ChlF) and vertical profile of canopies. By combining laserinduced fluorescence (LIF), sun-induced fluorescence (SIF) and canopy height distribution, the new instrument will low the simultaneous assessment of gross primary production (GPP), photosynthesis efficiency and above ground carbon stocks. Technical issues of the lidar development are discussed and expected performances are presented.

  17. Vertical level selection for temperature and trace gas profile retrievals using IASI

    NASA Astrophysics Data System (ADS)

    Vincent, R. A.; Dudhia, A.; Ventress, L. J.

    2015-06-01

    This work presents a new iterative method for optimally selecting a vertical retrieval grid based on the location of the information while accounting for inter-level correlations. Sample atmospheres initially created to parametrise the Radiative Transfer Model for the Television Infrared Observation Satellite Operational Vertical Sounder (RTTOV) forward model are used to compare the presented iterative selection method with two other common approaches, which are using levels of equal vertical spacing and selecting levels based on the cumulative trace of the averaging kernel matrix (AKM). This new method is shown to outperform compared methods for simulated profile retrievals of temperature, H2O, O3, CH4, and CO with the Infrared Atmospheric Sounding Interferometer (IASI). However, the benefits of using the more complicated iterative approach compared to the simpler cumulative trace method are slight and may not justify the added effort for the cases studied, but may be useful in other scenarios where temperature and trace gases have strong vertical gradients with significant estimate sensitivity. Furthermore, comparing retrievals using a globally optimised static grid vs. a locally adapted one shows that a static grid performs nearly as well for retrievals of O3, CH4, and CO. However, developers of temperature and H2O retrieval schemes may at least consider using adaptive or location specific vertical retrieval grids.

  18. A general framework for modelling the vertical organic matter profile in mineral and organic soils

    NASA Astrophysics Data System (ADS)

    Braakhekke, Maarten; Ahrens, Bernhard

    2016-04-01

    The vertical distribution of soil organic matter (SOM) within the mineral soil and surface organic layer is an important property of terrestrial ecosystems that affects carbon and nutrient cycling and soil heat and moisture transport. The overwhelming majority of models of SOM dynamics are zero-dimensional, i.e. they do not resolve heterogeneity of SOM concentration along the vertical profile. In recent years, however, a number of new vertically explicit SOM models or vertically explicit versions of existing models have been published. These models describe SOM in units of concentration (mass per unit volume) by means of a reactive-transport model that includes diffusion and/or advection terms for SOM transport, and vertically resolves SOM inputs and factors that influence decomposition. An important assumption behind these models is that the volume of soil elements is constant over time, i.e. not affected by SOM dynamics. This assumption only holds if the SOM content is negligible compared to the mineral content. When this is not the case, SOM input or loss in a soil element may cause a change in volume of the element rather than a change in SOM concentration. Furthermore, these volume changes can cause vertical shifts of material relative to the surface. This generally causes material in an organic layer to gradually move downward, even in absence of mixing processes. Since the classical reactive-transport model of the SOM profile can only be applied to the mineral soil, the surface organic layer is usually either treated separately or not explicitly considered. We present a new and elegant framework that treats the surface organic layer and mineral soil as one continuous whole. It explicitly accounts for volume changes due to SOM dynamics and changes in bulk density. The vertical shifts resulting from these volume changes are included in an Eulerian representation as an additional advective transport flux. Our approach offers a more elegant and realistic

  19. Retrieving vertical profiles of water-cloud droplet effective radius: Algorithm modification and preliminary application

    NASA Astrophysics Data System (ADS)

    Chang, Fu-Lung; Li, Zhanqing

    2003-12-01

    [2002] proposed a new cloud microphysics retrieval technique that can estimate the vertical profile of droplet effective radius (DER) for water clouds using multispectral near-infrared (NIR) measurements. The underlying principle of the retrieval technique is that radiance measurements at distinct multi-NIR wavelengths possess different penetration depths inside the cloud and this conveys certain information on the DER vertical profile (DVP). However, this information is insufficient to retrieve any shape of DVP and thus a linear DVP was assumed. In this study, three DVPs are examined: (1) as in [2002], a linear DVP proportional to the in-cloud optical depth, (2) a linear DVP proportional to the height within the cloud, and (3) a DVP where the liquid water content (LWC) within the cloud varies linearly with height. The latter two assumptions are in closer conformity with in-situ observations. Algorithms that can retrieve both the DVP and cloud liquid water path (LWP) are presented. The cloud LWPs derived based on the retrieved DVPs are more sound than those obtained from assuming a vertical-constant DER profile. To enhance the DVP retrievals, a split-window technique is presented to better estimate the amount of above-cloud precipitable water (PW). The retrieval algorithms are applied to the MODIS Level-1B 1-km data and presently tested for two stratiform cloud cases observed over the north-central Oklahoma where independent cloud microphysics data are available from the United States Department of Energy's Atmospheric Radiation Measurement (ARM) Program. Good agreements in the retrieved DER profile, LWP, and above-cloud PW are found in a preliminary demonstration of the new approach. Sensitivity of the retrieved DER profile to uncertainties in the above-cloud PW and surface albedos is also discussed.

  20. Development of balloon-borne CO2 sonde: CO2 vertical profile (0-10km) observations and comparison with the air craft measurements

    NASA Astrophysics Data System (ADS)

    Ouchi, M.; Matsumi, Y.; Nakayama, T.; Machida, T.; Matsueda, H.; Sawa, Y.; Tanaka, T.; Morino, I.; Uchino, O.

    2012-12-01

    The atmospheric CO2 concentration has drastically increased since the Industrial Revolution due to the mass consumption of fossil fuels and natural gas by human activities. CO2 is considered to be a major factor of global warming; therefore it is important to measure CO2 correctly. CO2 vertical profile measurement is the key to estimate CO2 sources and sinks in high precision. However, current CO2 monitoring sites are limited and there are few CO2 vertical profile measurements. We have been developing a balloon-borne instrument that can measure the vertical distribution of CO2 in any place in the world under any kind of weather conditions (CO2 sonde). The target specifications of altitude range is from surface to 10 km. Time resolution is 1min. The CO2 sensor, originally developed for upper air sounding by our team, is based on the non-dispersed infrared absorption spectroscopy technique (NDIR) at the wavelengths of 4.0 and 4.3 micrometer. The data of the optical infrared absorption are transmitted through a GPS sonde with temperature, humidity and GPS data every second. In this study, we will show simultaneous measurement campaigns of the balloon-borne instruments and in-situ aircraft measurements in January and February 2011 in the Tokyo metropolitan area in Japan. We will present the comparisons between the results of CO2 sonde (5 flights) and two types of aircraft measurements. One is observed by the CONTRAIL (Comprehensive Observation Network for TRace gases by AIrLiner) and the other is chartered flight measurements operated by NIES/JAXA.

  1. Vertical carbon-14 profiles for resolving spatial variability in recharge in arid environments

    NASA Astrophysics Data System (ADS)

    Wood, Cameron; Cook, Peter G.; Harrington, Glenn A.

    2015-01-01

    Groundwater age tracers are often measured to help constrain estimates of groundwater recharge, especially in arid environments where other methods are unsuitable. However multiple processes can influence the shape of vertical tracer profiles in an aquifer including (1) variation in tracer input concentrations from the unsaturated zone, (2) the role of diffusion in transporting tracer into the aquifer when fluxes are low and (3) spatial variability in recharge. This study demonstrates the influence of spatially variable recharge and spatially variable carbon-14 (14C) activities in the unsaturated zone on vertical 14C profiles in groundwater. Through groundwater flow and solute transport modelling, we demonstrate that recharge estimated from single point measurements of 14C may be wrong more than an order of magnitude when unsaturated zone 14C activities and recharge vary spatially. We then present a case study from the Ti Tree Basin in arid central Australia, where detailed profiles of 14C activity in unsaturated zone gas and groundwater have been measured, and spatial variability in unsaturated zone 14C is observed (ranging from 54 to 106 pMC above the watertable). Through modelling our data, we show that when unsaturated zone 14C activities are known, measurement of the 14C profile can help constrain estimates of recharge and its spatial variability. This approach improves our understanding of groundwater flow in the Ti Tree Basin, by showing mountain front recharge to be an important mechanism.

  2. Preliminary performance of a vertical-attitude takeoff and landing, supersonic cruise aircraft concept having thrust vectoring integrated into the flight control system

    NASA Technical Reports Server (NTRS)

    Robins, A. W.; Beissner, F. L., Jr.; Domack, C. S.; Swanson, E. E.

    1985-01-01

    A performance study was made of a vertical attitude takeoff and landing (VATOL), supersonic cruise aircraft concept having thrust vectoring integrated into the flight control system. Those characteristics considered were aerodynamics, weight, balance, and performance. Preliminary results indicate that high levels of supersonic aerodynamic performance can be achieved. Further, with the assumption of an advanced (1985 technology readiness) low bypass ratio turbofan engine and advanced structures, excellent mission performance capability is indicated.

  3. First characterization and validation of FORLI-HNO3 vertical profiles retrieved from IASI/Metop

    NASA Astrophysics Data System (ADS)

    Ronsmans, Gaétane; Langerock, Bavo; Wespes, Catherine; Hannigan, James W.; Hase, Frank; Kerzenmacher, Tobias; Mahieu, Emmanuel; Schneider, Matthias; Smale, Dan; Hurtmans, Daniel; De Mazière, Martine; Clerbaux, Cathy; Coheur, Pierre-François

    2016-09-01

    Knowing the spatial and seasonal distributions of nitric acid (HNO3) around the globe is of great interest and allows us to comprehend the processes regulating stratospheric ozone, especially in the polar regions. Due to its unprecedented spatial and temporal sampling, the nadir-viewing Infrared Atmospheric Sounding Interferometer (IASI) is capable of sounding the atmosphere twice a day globally, with good spectral resolution and low noise. With the Fast Optimal Retrievals on Layers for IASI (FORLI) algorithm, we are retrieving, in near real time, columns as well as vertical profiles of several atmospheric species, among which is HNO3. We present in this paper the first characterization of the FORLI-HNO3 profile products, in terms of vertical sensitivity and error budgets. We show that the sensitivity of IASI to HNO3 is highest in the lower stratosphere (10-20 km), where the largest amounts of HNO3 are found, but that the vertical sensitivity of IASI only allows one level of information on the profile (degrees of freedom for signal, DOFS; ˜ 1). The sensitivity near the surface is negligible in most cases, and for this reason, a partial column (5-35 km) is used for the analyses. Both vertical profiles and partial columns are compared to FTIR ground-based measurements from the Network for the Detection of Atmospheric Composition Change (NDACC) to characterize the accuracy and precision of the FORLI-HNO3 product. The profile validation is conducted through the smoothing of the raw FTIR profiles by the IASI averaging kernels and gives good results, with a slight overestimation of IASI measurements in the upper troposphere/lower stratosphere (UTLS) at the six chosen stations (Thule, Kiruna, Jungfraujoch, Izaña, Lauder and Arrival Heights). The validation of the partial columns (5-35 km) is also conclusive with a mean correlation of 0.93 between IASI and the FTIR measurements. An initial survey of the HNO3 spatial and seasonal variabilities obtained from IASI

  4. Vertical profiles of aerosol optical properties and the solar heating rate estimated by combining sky radiometer and lidar measurements

    NASA Astrophysics Data System (ADS)

    Kudo, Rei; Nishizawa, Tomoaki; Aoyagi, Toshinori

    2016-07-01

    The SKYLIDAR algorithm was developed to estimate vertical profiles of aerosol optical properties from sky radiometer (SKYNET) and lidar (AD-Net) measurements. The solar heating rate was also estimated from the SKYLIDAR retrievals. The algorithm consists of two retrieval steps: (1) columnar properties are retrieved from the sky radiometer measurements and the vertically mean depolarization ratio obtained from the lidar measurements and (2) vertical profiles are retrieved from the lidar measurements and the results of the first step. The derived parameters are the vertical profiles of the size distribution, refractive index (real and imaginary parts), extinction coefficient, single-scattering albedo, and asymmetry factor. Sensitivity tests were conducted by applying the SKYLIDAR algorithm to the simulated sky radiometer and lidar data for vertical profiles of three different aerosols, continental average, transported dust, and pollution aerosols. The vertical profiles of the size distribution, extinction coefficient, and asymmetry factor were well estimated in all cases. The vertical profiles of the refractive index and single-scattering albedo of transported dust, but not those of transported pollution aerosol, were well estimated. To demonstrate the performance and validity of the SKYLIDAR algorithm, we applied the SKYLIDAR algorithm to the actual measurements at Tsukuba, Japan. The detailed vertical structures of the aerosol optical properties and solar heating rate of transported dust and smoke were investigated. Examination of the relationship between the solar heating rate and the aerosol optical properties showed that the vertical profile of the asymmetry factor played an important role in creating vertical variation in the solar heating rate. We then compared the columnar optical properties retrieved with the SKYLIDAR algorithm to those produced with the more established scheme SKYRAD.PACK, and the surface solar irradiance calculated from the SKYLIDAR

  5. Characteristics of ozone vertical profile observed in the boundary layer around Beijing in autumn.

    PubMed

    Ma, Zhiqiang; Zhang, Xiaoling; Xu, Jing; Zhao, Xiujuan; Meng, Wei

    2011-01-01

    In the autumn of 2008, the vertical profiles of ozone and meteorological parameters in the low troposphere (0-1000 m) were observed at two sites around Beijing, specifically urban Nanjiao and rural Shangdianzi. At night and early morning, the lower troposphere divided into two stratified layers due to temperature inversion. Ozone in the lower layer showed a large gradient due to the titration of NO. Air flow from the southwest brought ozone-rich air to Beijing, and the ozone profiles were marked by a continuous increase in the residual layer at night. The accumulated ozone in the upper layer played an important role in the next day's surface peak ozone concentration, and caused a rapid increase in surface ozone in the morning. Wind direction shear and wind speed shear exhibited different influences on ozone profiles and resulted in different surface ozone concentrations in Beijing.

  6. Hemispheric aerosol vertical profiles: anthropogenic impacts on optical depth and cloud nuclei.

    PubMed

    Clarke, Antony; Kapustin, Vladimir

    2010-09-17

    Understanding the effect of anthropogenic combustion upon aerosol optical depth (AOD), clouds, and their radiative forcing requires regionally representative aerosol profiles. In this work, we examine more than 1000 vertical profiles from 11 major airborne campaigns in the Pacific hemisphere and confirm that regional enhancements in aerosol light scattering, mass, and number are associated with carbon monoxide from combustion and can exceed values in unperturbed regions by more than one order of magnitude. Related regional increases in a proxy for cloud condensation nuclei (CCN) and AOD imply that direct and indirect aerosol radiative effects are coupled issues linked globally to aged combustion. These profiles constrain the influence of combustion on regional AOD and CCN suitable for challenging climate model performance and informing satellite retrievals.

  7. Global profiles of the direct aerosol effect using vertically resolved aerosol data

    NASA Astrophysics Data System (ADS)

    Korras Carraca, Marios Bruno; Pappas, Vasilios; Matsoukas, Christos; Hatzianastassiou, Nikolaos; Vardavas, Ilias

    2014-05-01

    Atmospheric aerosols, both natural and anthropogenic, can cause climate change through their direct, indirect, and semi-direct effects on the radiative energy budget of the Earth-atmosphere system. In general, aerosols cause cooling of the surface and the planet, while they warm the atmosphere due to scattering and absorption of incoming solar radiation. The importance of vertically resolved direct radiative effect (DRE) and heating/cooling effects of aerosols is strong, while large uncertainties still lie with their magnitudes. In order to be able to quantify them throughout the atmosphere, a detailed vertical profile of the aerosol effect is required. Such data were made available recently by the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) on board the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite. CALIOP is the first polarization lidar to fly in space and has been acquiring unique data on aerosols and clouds since June 2006. The aim of this study is to investigate both the vertically resolved geographic and seasonal variation of the DRE due to aerosols. The vertical profile of DRE under all-sky and clear-sky conditions is computed using the deterministic spectral radiative transfer model FORTH. From the DRE, the effect on atmospheric heating/cooling rate profiles due to aerosols can also be derived. We use CALIOP Level 2-Version 3 Layer aerosol optical depth data as input to our radiation transfer model, for a period of 3 complete years (2007-2009). These data are provided on a 5 km horizontal resolution and in up to 8 vertical layers and have been regridded on our model horizontal and vertical resolutions. We use cloud data from the International Satellite Cloud Climatology Project (ISCCP), while the aerosol asymmetry factor and single scattering albedo are taken from the Global Aerosol Data Set (GADS). The model computations are performed on a monthly, 2.5°× 2.5° resolution on global scale, at 40

  8. Wintertime vertical profiles of air pollutants over a suburban area in central Taiwan

    NASA Astrophysics Data System (ADS)

    Chen, Chien-Lung; Tsuang, Ben-Jei; Tu, Chia-Ying; Cheng, Wan-Li; Lin, Min-Der

    Using a tethered balloon, vertical air pollutant concentrations (CO, SO 2, NO, NO 2 and O 3) were measured in central Taiwan during field campaigns in the winters of 1999 and 2001. Modified novel lightweight sampling equipment was used to take samples at heights of 1, 13, 100, 300, 500 and 1200 m. A balloon was launched every 3 h and in total there were 133 flights during the three campaigns. The data were collected in order to examine the temporal and vertical variations of pollutants. The average daytime profiles showed greater vertical convection mixing in unstable circumstances. The characteristics of shapes and time behavior of profiles are reported. Except for a slight decrease near the ground and strong photochemical reactions at clear daytime, titration of O 3 by NO was observed at all altitudes in the atmospheric boundary layer during these campaigns. Ground level ozone may be contributed by downward mixing from above. A fair correlation appeared between the maximum ozone concentration at the surface during the daytime ( C¯0 Max) and average ozone concentration above the NBL ( C¯a NBL). A linear regression equation is shown as C¯0 Max=29+0.91 C¯a NBL.

  9. Variability of the vertical profile of wind speed: characterization at various time scales and analytical approximation

    NASA Astrophysics Data System (ADS)

    Jourdier, Bénédicte; Plougonven, Riwal; Drobinski, Philippe; Dupont, Jean-Charles

    2014-05-01

    Wind measurements are key for the wind resource assessment. But as wind turbines get higher, wind measurement masts are often lower than the future wind turbine hub height. Therefore one of the first steps in the energy yield assessment is the vertical extrapolation of wind measurements. Such extrapolation is often done by approximating the vertical profile of wind speed with an analytical expression: either a logarithmic law which has a theoretical basis in Monin-Obukhov similarity theory; or a power law which is empirical. The present study analyzes the variability of the wind profile and how this variability affects the results of the vertical extrapolation methods. The study is conducted with data from the SIRTA observatory, 20km south of Paris (France). A large set of instrumentation is available, including sonic anemometers at 10 and 30 meters, a LIDAR measuring wind speeds from 40 to 200 meters and a SODAR measuring wind speeds starting from 100m up to 1km. The comparison between the instruments enables to characterize the measurements uncertainties. The observations show that close to the ground the wind is stronger during daytime and weaker at night while higher, around 150 m, the wind is weaker during daytime and stronger at night. Indeed the wind shear has a pronounced diurnal cycle. The vertical extrapolation methods currently used in the industry do not usually take into account the strong variability of the wind profile. The often fit the parameters of the extrapolation law, not on each time step, but on time-averaged profiles. The averaging period may be the whole measurement period or some part of it: there may be one constant parameter computed on the wind profile that was averaged on the whole year of measures, or the year of measures may be divided into a small number of cases (for example into night or daytime data, or into 4 seasons) and the parameter is adjusted for each case. The study analyzes thoroughly the errors generated by both

  10. Long-Term Mean Vertical Motion over the Tropical Pacific: Wind-Profiling Doppler Radar Measurements

    NASA Astrophysics Data System (ADS)

    Gage, K. S.; McAfee, J. R.; Carter, D. A.; Ecklund, W. L.; Riddle, A. C.; Reid, G. C.; Balsley, B. B.

    1991-12-01

    Measurement from Christmas Island (2^circN, 157^circW) of long-term mean vertical motions in the tropical atmosphere using very-high-frequency wind-profiling Doppler radar show that there is a transition from downward motion in the free troposphere to upward motion in the upper troposphere and lower stratosphere. The observations in the free troposphere are consistent with a balance between adiabatic and diabatic heating and cooling rates in a clear atmosphere. Comparison of the results at Christmas Island during El Nino and non-El Nino conditions with earlier results obtained for stratiform rain conditions over Pohnpei, Federated States of Micronesia, show that cirrus clouds in the vicinity of the tropopause likely play an important role in determining the sense and magnitude of vertical motions in this region. These results have implications for the exchange of mass between the troposphere and stratosphere over the tropics.

  11. A simple deep-towed vertical array for high-resolution reflection seismic profiling

    NASA Astrophysics Data System (ADS)

    Herber, R.; Nuppenau, V.; Weigel, W.; Wong, H. K.

    1986-06-01

    A simple, low cost, deep-towed system for high-resolution reflection seismic profiling is described. It consists of a vertical array with two hydrophones having a separation of 2.2 m and rigidly mounted onto streamlined tow bodies. Improvement of the signal-to-noise ratio is attained by simple stacking of the hydrophone outputs after signal conditioning and travel time corrections. The suppression of side echoes and surface reflections is achieved by an analog procedure which in effect improves the directional characteristics of the array. A circuit for automatic gain control is included to enhance weak signals as well as to suppress ringing. Results in Kiel Bay and over the crest of the Jan Mayen Ridge (northern Atlantic) suggest that this simple vertical array may supplement air gun systems better than conventional, surface pinger-type equipment.

  12. Long-Term Mean Vertical Motion over the Tropical Pacific: Wind-Profiling Doppler Radar Measurements.

    PubMed

    Gage, K S; McAfee, J R; Carter, D A; Ecklund, W L; Riddle, A C; Reid, G C; Balsley, B B

    1991-12-20

    Measurement from Christmas Island (2 degrees N, 157 degrees W) of long-term mean vertical motions in the tropical atmosphere using very-high-frequency wind-profiling Doppler radar show that there is a transition from downward motion in the free troposphere to upward motion in the upper troposphere and lower stratosphere. The observations in the free troposphere are consistent with a balance between adiabatic and diabatic heating and cooling rates in a clear atmosphere. Comparison of the results at Christmas Island during El Niño and non-El Niño conditions with earlier results obtained for stratiform rain conditions over Pohnpei, Federated States of Micronesia, show that cirrus clouds in the vicinity of the tropopause likely play an important role in determining the sense and magnitude of vertical motions in this region. These results have implications for the exchange of mass between the troposphere and stratosphere over the tropics.

  13. Vertical Tracer Concentration Profiles Measured During the Joint Urban 2003 Dispersion Study

    SciTech Connect

    Flaherty, Julia E.; Lamb, Brian K.; Allwine, K Jerry; Allwine, Eugene J.

    2007-12-01

    An atmospheric tracer dispersion study known as Joint Urban 2003 was conducted in Oklahoma City, Oklahoma during the summer of 2003. As part of this field program, vertical concentration profiles were measured at approximately 1 km from downtown tracer gas release locations. These profiles indicated that the urban landscape was very effective in mixing the plume vertically. The height of the plume centerline (as determined by the maximum concentration over the depth of the measurements) for any specific 30 min period varied over the 65 m measurement range. Most of the variations in tracer concentration observed in the profile time series were related to changes in wind direction as opposed to changes in turbulence. As a simple analysis tool for emergency response, maximum normalized concentration curves were developed with 5-minute averaged measurements. These curves give the maximum concentration (normalized by the release rate) that would be observed as a function of downwind distance in an urban area. The 5-min data resulted in greater concentrations than predicted with a simple Gaussian plume model. However, the curve compared well with results from a computational fluid dynamics simulation. This dispersion dataset is a valuable asset not only for refining air quality models, but also for developing new tools for emergency response personnel in the event of a toxic release.

  14. Profiles of flow discharged from vertical rotating pipes: A contrast between inviscid liquid and granular jets

    NASA Astrophysics Data System (ADS)

    Weidman, P. D.; Kubitschek, J. P.; Medina, A.

    2008-11-01

    The stability of viscous rotating liquid columns and their application to rotating viscous liquid jets aligned under gravity is reviewed. Experiments on stable viscous fluid flow discharged from rotating vertical pipes exhibit very weak contraction. We present an elementary liquid jet analysis to understand this phenomenon. Indeed, our inviscid model of a slender rotating inviscid liquid jet shows that rotation suppresses contraction. Next we study the comparable problem for granular flow. Our model for noncohesive granular flow emanating from a vertical pipe rotating about its central axis, valid for sufficiently large rotation rate, shows that the granular profiles blossom rather than contract. The profiles of both the liquid and granular jets depend on the same dimensionless parameters—an exit Froude number Fr0 and an exit swirl parameter χ0. The limitations of both models are discussed. Experimental data for granular jet profiles compare well with the collision-free granular flow model in its range of applicability. A criterion for the rotation rate at which particles adjacent to the inner wall of the rotating pipe cease to flow is also given and compared to experiment.

  15. Evaluation strategies for vertical profiles of physical properties simulated by multilayer snowpack models

    NASA Astrophysics Data System (ADS)

    Morin, Samuel; Hagenmuller, Pascal; Dumont, Marie; Lafaysse, Matthieu

    2016-04-01

    Multilayer snowpack models aim at representing processes responsible for the layering of a one-dimensional snowpack, and its time evolution. Their evaluation should ideally not only rely on observations of vertically integrated properties (depth, albedo, snow water equivalent, surface temperature) but also vertical profiles of properties such as density, liquid water content, specific surface area, penetration resistance etc. However, even at well-documented sites where meteorological conditions are monitored with the highest possible accuracy, the direct comparison of simulated and observed profiles has proven challenging. This is due, not only to intrinsic model errors and snow observation uncertainties, which are classically considered, but also to errors of the meteorological observations used to drive the snowpack models and snowpack heterogeneity. These sources of errors stratigraphic mismatches, i.e. a layer at the same depth in the simulated and observed snowpack may not necessarily correspond to the same stratigraphic horizon. In addition, such errors accumulate during the course of a snow season. Altogether, this makes it particularly difficult to disentangle errors due to the snowpack model itself (which is the primary goal of such comparisons) from other sources of errors. This presentation will review various approaches already developed (e.g. Lehning and Fierz, CRST 2001) and introduce yet-to-implement methods, with the aim to provide a framework allowing improved comparisons between observed and simulated snow profiles, which is a long-lasting need of the snow modelling community.

  16. Vertical and horizontal corneal epithelial thickness profiles determined by ultra-high resolution optical coherence tomography

    PubMed Central

    Du, Chixin; Wang, Jianhua; Cui, Lele; Shen, Meixiao; Yuan, Yimin

    2011-01-01

    Purpose To measure vertical and horizontal thickness profiles of the central and peripheral corneal epithelium and determine if daytime changes occur. Methods Forty eyes of 20 normal subjects were imaged by ultra-high resolution spectral domain optical coherence tomography to profile the corneal epithelial thickness from the edge of Bowman’s layer to the central cornea across the vertical and horizontal meridians. Measurements were made at 10:00 AM and again at 6, 8 hours later. Results The baseline vertical meridional epithelial thickness was thinnest, 42.9±4.1 μm, at the edge of Bowman’s layer in the superior region. It increased in thickness (p<0.01), towards the central cornea. The central epithelium averaged 52.5±2.4 μm, becoming thickest, 55.2±2.5 μm, in the inferior pericentral region. It thinned towards the inferior periphery, reaching 51.3±5.1 μm at the edge of Bowman’s layer (p<0.01). Along the horizontal meridian, the epithelium was thickest at the nasal side, 58.6±5.1 μm, and temporal side, 59.3±6.6 μm, near the edges of Bowman’s layer. It thinned towards the central cornea. There were no significant changes in the epithelial thickness at any location over 8 hours. Conclusion Epithelial thickness varied over the horizontal and vertical meridians and appeared stable during the daytime. PMID:22357393

  17. 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

  18. Multifractal analysis of vertical profiles of soil penetration resistance at the field scale

    NASA Astrophysics Data System (ADS)

    Siqueira, G. M.; Silva, E. F. F.; Montenegro, A. A. A.; Vidal Vázquez, E.; Paz-Ferreiro, J.

    2013-07-01

    Soil penetration resistance (PR) is widely used as an indirect indicator of soil strength. Soil PR is linked to basic soil properties and correlated to root growth and plant production, and as such it is extensively used as a practical tool for assessing soil compaction and to evaluate the effects of soil management. This study investigates how results from multifractal analysis can quantify key elements of depth-dependent soil PR profiles and how this information can be used at the field scale. We analysed multifractality of 50 PR vertical profiles, measured from 0 to 60 cm depth and randomly located on a 6.5 ha sugar cane field in northeastern Brazil. The scaling property of each profile was typified by singularity, and Rényi spectra estimated by the method of moments. The Hurst exponent was used to parameterize the autocorrelation of the vertical PR data sets. The singularity and Rènyi spectra showed that the vertical PR data sets exhibited a well-defined multifractal structure. Hurst exponent values were close to 1, ranging from 0.944 to 0.988, indicating strong persistence in PR variation with soil depth. Also, the Hurst exponent was negatively and significantly correlated to coefficient of variation (CV), skewness and maximum values of the depth-dependent PR. Multifractal analysis added valuable information to describe the spatial arrangement of depth-dependent penetrometer data sets, which was not taken into account by classical statistical indices. Multifractal parameters were mapped over the experimental field and compared with mean and maximum values of PR. Combination of spatial variability survey and multifractal analysis appear to be useful to manage soil compaction.

  19. A look inside the San Andreas Fault at Parkfield through vertical seismic profiling.

    PubMed

    Chavarria, J Andres; Malin, Peter; Catchings, Rufus D; Shalev, Eylon

    2003-12-01

    The San Andreas Fault Observatory at Depth pilot hole is located on the southwestern side of the Parkfield San Andreas fault. This observatory includes a vertical seismic profiling (VSP) array. VSP seismograms from nearby microearthquakes contain signals between the P and S waves. These signals may be P and S waves scattered by the local geologic structure. The collected scattering points form planar surfaces that we interpret as the San Andreas fault and four other secondary faults. The scattering process includes conversions between P and S waves, the strengths of which suggest large contrasts in material properties, possibly indicating the presence of cracks or fluids.

  20. A Look Inside the San Andreas fault at Parkfield Through Vertical Seismic Profiling

    USGS Publications Warehouse

    Chavarria, J.A.; Malin, P.; Catchings, R.D.; Shalev, E.

    2003-01-01

    The San Andreas Fault Observatory at Depth pilot hole is located on the southwestern side of the Parkfield San Andreas fault. This observatory includes a vertical seismic profiling (VSP) array. VSP seismograms from nearby micro-earthquakes contain signals between the P and S waves. These signals may be P and S waves scattered by the local geologic structure. The collected scattering points form planar surfaces that we interpret as the San Andreas fault and four other secondary faults. The scattering process includes conversions between P and S waves, the strengths of which suggest large contrasts in material properties, possibly indicating the presence of cracks or fluids.

  1. ACTRIS aerosol vertical profile data and observations: potentiality and first examples of integrated studies with models

    NASA Astrophysics Data System (ADS)

    Mona, Lucia; Benedetti, Angela; D'Amico, Giuseppe; Myhre, Cathrine Lund; Schulz, Michael; Wandinger, Ulla; Laj, Paolo; Pappalardo, Gelsomina

    2016-04-01

    The ACTRIS-2 project, funded by Horizon 2020, addresses the scope of integrating state-of-the-art European ground-based stations for long term observations of aerosols, clouds and short lived gases, capitalizing on the work of FP7-ACTRIS. It aims at achieving the construction of a user-oriented RI, unique in the EU-RI landscape for providing 4-D integrated high-quality data from near-surface to high altitude (vertical profiles and total-column) which are relevant to climate and air-quality research. ACTRIS-2 develops and implements, in a large network of stations in Europe and beyond, observational protocols that permit the harmonization of collected data and their dissemination. ACTRIS secures provision and dissemination of a unique set of data and data-products that would not otherwise be available with the same level of quality and standardization. This results from a 10-year plus effort in constructing a research infrastructure capable of responding to community needs and requirements, and has been engaged since the start of the FP5 EU commission program. ACTRIS ensures compliance with reporting requirements (timing, format, traceability) defined by the major global observing networks. EARLINET (European Aerosol research Lidar NETwork), the aerosol vertical profiling component of ACTRIS, is providing since May 2000 vertical profiles of aerosol extinction and backscatter over Europe. A new structure of the EARLINET database has been designed in a more user oriented approach reporting new data products which are more effective for specific uses of different communities. In particular, a new era is starting with the Copernicus program during which the aerosol vertical profiling capability will be fundamental for assimilation and validation purposes. The new data products have been designed thanks to a strong link with EARLINET data users, first of all modeling and satellite communities, established since the beginning of EARLINET and re-enforced within ACTRIS2

  2. Measurements of Aerosol Vertical Profiles and Optical Properties during INDOEX 1999 Using Micro-Pulse Lidars

    NASA Technical Reports Server (NTRS)

    Welton, Ellsworth J.; Voss, Kenneth J.; Quinn, Patricia K.; Flatau, Piotr J.; Markowicz, Krzysztof; Campbell, James R.; Spinhirne, James D.; Gordon, Howard R.; Johnson, James E.; Starr, David OC. (Technical Monitor)

    2001-01-01

    lower troposphere) calculates extinction near the surface in agreement with the ship-level measurements only when the MBL aerosols are well mixed with aerosols above. Finally, a review of the MPL extinction profiles showed that the model of aerosol vertical extinction developed during an earlier INDOEX field campaign (at the Maldives) did not correctly describe the true vertical distribution over the greater Indian Ocean region. Using the average extinction profile and AOD obtained during marine conditions, a new model of aerosol vertical extinction was determined for marine atmospheres over the Indian Ocean. A new model of aerosol vertical extinction for polluted marine atmospheres was also developed using the average extinction profile and AOD obtained during marine conditions influenced by continental aerosols.

  3. Investigation of seasonal dynamics of β- and γ-radiation Helds vertical profile in the surface atmospheric layer

    NASA Astrophysics Data System (ADS)

    Ryabkina, K. S.; Kondratyeva, A. G.; Nagorskiy, P. M.; Yakovleva, V. S.

    2016-06-01

    This paper is devoted to the seasonal dynamics of β- and γ-radiation field vertical profile in the surface atmospheric layer study. The findings revealed the following: a) significant seasonal variation in vertical distribution characteristics fields β- and γ-radiation b) reduced β-radiation flux density and γ-radiation dose with increasing height is maintained in the range of spring and fall, namely, starting with snow melt and finishing its setting; c) distortion vertical profile in the winter season, an inverse relationship β-flux density and dose rate of γ-radiation from the heights above the earth's surface was registered.

  4. The effect of aerosol vertical profiles on satellite-estimated surface particle sulfate concentrations

    SciTech Connect

    Liu, Yang; Wang, Zifeng; Wang, Jun; Ferrare, Richard A.; Newsom, Rob K.; Welton, Ellsworth J.

    2011-02-15

    The aerosol vertical distribution is an important factor in determining the relationship between satellite retrieved aerosol optical depth (AOD) and ground-level fine particle pollution concentrations. We evaluate how aerosol profiles measured by ground-based lidar and simulated by models can help improve the association between AOD retrieved by the Multi-angle Imaging Spectroradiometer (MISR) and fine particle sulfate (SO4) concentrations using matched data at two lidar sites. At the Goddard Space Flight Center (GSFC) site, both lidar and model aerosol profiles marginally improve the association between SO4 concentrations and MISR fractional AODs, as the correlation coefficient between cross-validation (CV) and observed SO4 concentrations changes from 0.87 for the no-scaling model to 0.88 for models scaled with aerosol vertical profiles. At the GSFC site, a large amount of urban aerosols resides in the well-mixed boundary layer so the column fractional AODs are already excellent indicators of ground-level particle pollution. In contrast, at the Atmospheric Radiation Measurement Program (ARM) site with relatively low aerosol loadings, scaling substantially improves model performance. The correlation coefficient between CV and observed SO4 concentrations is increased from 0.58 for the no-scaling model to 0.76 in the GEOS-Chem scaling model, and the model bias is reduced from 17% to 9%. In summary, despite the inaccuracy due to the coarse horizontal resolution and the challenges of simulating turbulent mixing in the boundary layer, GEOS-Chem simulated aerosol profiles can still improve methods for estimating surface aerosol (SO4) mass from satellite-based AODs, particularly in rural areas where aerosols in the free troposphere and any long-range transport of aerosols can significantly contribute to the column AOD.

  5. Cloud vertical structure, radiative heating profile and diurnal variation during TOGA COARE

    NASA Astrophysics Data System (ADS)

    Qian, Taotao

    This thesis consists of two parts: (1) the vertical structure of clouds and radiative heating during TOGA COARE and (2) diurnal variations during TOGA COARE. The purpose of the first part (Chapter 1) is to determine a realistic gridded (1 degree by 1 degree) cloud vertical structure and radiative heating profile for the Intensive Flux Array (IFA) during the Tropical Ocean Global Atmosphere (TOGA) Coupled Ocean Atmosphere Response Experiment (COARE). First, we deduce the cloud vertical structure from the sounding data using an improved relative humidity (RH) threshold method. The RH threshold is height-dependent and is tuned by three surface and TOA observations of clouds: the Micropulse Lidar (MPL), the High-Resolution Infrared Sounder (HIRS) and the International Satellite Cloud Climatology Project (ISCCP). Then, a modified CCM3 Column Radiation Model (CRM) is used to calculate the radiative heating profiles. The modification of the CRM replaces the model microphysics with the observed microphysics profiles. The calculated radiation budgets are shown to be consistent with the surface and top of the atmosphere (TOA) observations and are much better than those of the standard version of the CRM. The purpose of the second part (Chapter 2) is to test different diurnal variation mechanisms, that have been proposed in previous studies, by using the abundant observational data obtained during TOGA COARE. The preliminary findings are: (1) The stratiform precipitation lags the convective precipitation, suggesting that the effect of the life cycle of the mesoscale convective systems (MCS) is important to the midnight rainfall maximum; i.e., the stratiform component helps to shift the maximum toward midnight. This supports the MCS life cycle mechanism. (2) This study supports the direct radiation-convection interaction mechanism and emphasize that the variation is strongly affected by the variation of upper-level clouds. (3) The current study does not, however, support the

  6. Vertical geochemical profiling of an aquifer contaminated with JP-4 fuel

    SciTech Connect

    Fang, Jiasong; Barcelona, M.J.

    1996-12-31

    Soil samples were collected at a site contaminated with jet fuel at Wurtsmith Air Force Base, Michigan, and were analyzed for aromatic hydrocarbons, aromatic acid metabolites, and phospholipid ester-linked fatty acids (PLFA). Vertically, concentrations of alkylbenzenes (with C1-C4 substitutions) ranged from less than 1.0 to 21.69 {mu}g/kg away from water table to 2605.96 {mu}g/kg in samples taken at water table in the contaminated areas. Contaminant concentration decreased to less than 1.0 {mu}g/kg in downgradient zone. Aromatic acid metabolites identified include o-, m-, and p-toluic acid, 2,4-, 2,5-, 3,5-, 2,6- and 3,4- dimethylbenzoic acid, and 2,4,6-trimethylbenzoic acid. The contaminant profiles paralleled to the concentration profiles of alkylbenzenes, suggesting that the production of aromatic acid was associated with the microbial degradation of aromatic hydrocarbons. PLFA ranging from C{sub 12} to C{sub 20} were determined in soil samples, including saturated and monounsaturated fatty acids. The only polyenoic acid detected was 18:2w6, a biomarker for protozoa. The total microbial biomass calculated from PLFA showed varied profiles within wells at different depths as well as at different wells at similar depths indicating considerable microbial heterogeneity in the subsurface over depths or lateral distance. The PLFA profiles also suggested a dominant anaerobic and aerobic microbial community in the aquifer solids.

  7. The far-ultraviolet main auroral emission at Jupiter - Part 2: Vertical emission profile

    NASA Astrophysics Data System (ADS)

    Bonfond, B.; Gustin, J.; Gérard, J.-C.; Grodent, D.; Radioti, A.; Palmaerts, B.; Badman, S. V.; Khurana, K. K.; Tao, C.

    2015-10-01

    The aurorae at Jupiter are made up of many different features associated with a variety of generation mechanisms. The main auroral emission, also known as the main oval, is the most prominent of them as it accounts for approximately half of the total power emitted by the aurorae in the ultraviolet range. The energy of the precipitating electrons is a crucial parameter to characterize the processes at play which give rise to these auroral emissions, and the altitude of the emissions directly depends on this energy. Here we make use of far-UV (FUV) images acquired with the Advanced Camera for Surveys on board the Hubble Space Telescope and spectra acquired with the Space Telescope Imaging Spectrograph to measure the vertical profile of the main emissions. The altitude of the brightness peak as seen above the limb is ~ 400 km, which is significantly higher than the 250 km measured in the post-dusk sector by Galileo in the visible domain. However, a detailed analysis of the effect of hydrocarbon absorption, including both simulations and FUV spectral observations, indicates that FUV apparent vertical profiles should be considered with caution, as these observations are not incompatible with an emission peak located at 250 km. The analysis also calls for spectral observations to be carried out with an optimized geometry in order to remove observational ambiguities.

  8. Validation of vertical profile from atmosphere using ATOVS products and its impact over Indian region.

    NASA Astrophysics Data System (ADS)

    Mahandru, Riddhi; Kumar, Adarsh; Mitra, Ashim kumar

    This research paper summarizes the validation of atmospheric vertical profile using NOAA(National Oceanic and Atmospheric Administration)/ MetOp satellite derived data over India with radiosonde observations over a span of 8 months. NOAA's International Advanced Television and Infrared Observations satellite Vertical Sounder (ATOVS) processing package (IAPP) obtains temperature and moisture profiles in different pressure levels ranging from 1000hpa to 10hpa from real time direct broadcast (DB) receiving system installed at India Meteorological department. Different pressure levels were substituted to the same pressure levels for calculations of standard deviation, bias and RMSE (root mean square error) The sounder derived products like Total precipitable water vapor (TPW) and Lifting index(LI) from NOAA Satellite was also validated with radiosonde data which provided significant results for weather forecasting. The validation shows that the sounder provides unique information about the state of atmosphere and monitoring the convective environment for severe weather forecasting In addition to this, case study on severe weather events was analyzed using ATOVS products.

  9. High-latitude topside ionospheric vertical electron density profile changes in response to large magnetic storms

    NASA Astrophysics Data System (ADS)

    Benson, Robert F.; Fainberg, Joseph; Osherovich, Vladimir A.; Truhlik, Vladimir; Wang, Yongli; Bilitza, Dieter; Fung, Shing F.

    2016-05-01

    Large magnetic-storm-induced changes were detected in high-latitude topside vertical electron density profiles Ne(h) in a database of profiles and digital topside ionograms, from the International Satellites for Ionospheric Studies (ISIS) program, that enabled Ne(h) profiles to be obtained in nearly the same region of space before, during, and after a major magnetic storm (Dst < -100 nT). Storms where Ne(h) profiles were available in the high-latitude Northern Hemisphere had better coverage of solar wind parameters than storms with available Ne(h) profiles in the high-latitude Southern Hemisphere. Large Ne(h) changes were observed during all storms, with enhancements and depletions sometimes near a factor of 10 and 0.1, respectively, but with substantial differences in the responses in the two hemispheres. Large spatial and/or temporal Ne(h) changes were often observed during Dst minimum and during the storm recovery phase. The storm-induced Ne(h) changes were the most pronounced and consistent in the Northern Hemisphere in that large enhancements were observed during winter nighttime and large depletions during winter and spring daytime. The limited available cases suggested that these Northern Hemisphere enhancements increased with increases of the time-shifted solar wind velocity v, magnetic field B, and with more negative values of the B components except for the highest common altitude (1100 km) of the profiles. There was also some evidence suggesting that the Northern Hemisphere depletions were related to changes in the solar wind parameters. Southern Hemisphere storm-induced enhancements and depletions were typically considerably less with depletions observed during summer nighttime conditions and enhancements during summer daytime and fall nighttime conditions.

  10. Vertical velocity variance in the mixed layer from radar wind profilers

    USGS Publications Warehouse

    Eng, K.; Coulter, R.L.; Brutsaert, W.

    2003-01-01

    Vertical velocity variance data were derived from remotely sensed mixed layer turbulence measurements at the Atmospheric Boundary Layer Experiments (ABLE) facility in Butler County, Kansas. These measurements and associated data were provided by a collection of instruments that included two 915 MHz wind profilers, two radio acoustic sounding systems, and two eddy correlation devices. The data from these devices were available through the Atmospheric Boundary Layer Experiment (ABLE) database operated by Argonne National Laboratory. A signal processing procedure outlined by Angevine et al. was adapted and further built upon to derive vertical velocity variance, w_pm???2, from 915 MHz wind profiler measurements in the mixed layer. The proposed procedure consisted of the application of a height-dependent signal-to-noise ratio (SNR) filter, removal of outliers plus and minus two standard deviations about the mean on the spectral width squared, and removal of the effects of beam broadening and vertical shearing of horizontal winds. The scatter associated with w_pm???2 was mainly affected by the choice of SNR filter cutoff values. Several different sets of cutoff values were considered, and the optimal one was selected which reduced the overall scatter on w_pm???2 and yet retained a sufficient number of data points to average. A similarity relationship of w_pm???2 versus height was established for the mixed layer on the basis of the available data. A strong link between the SNR and growth/decay phases of turbulence was identified. Thus, the mid to late afternoon hours, when strong surface heating occurred, were observed to produce the highest quality signals.

  11. Vertical velocity variance in the mixed layer from radar wind profilers.

    SciTech Connect

    Eng, K.; Coulter, R. L.; Brutsaert, W.; Environmental Research; Cornell Univ.

    2003-11-01

    Vertical velocity variance data were derived from remotely sensed mixed layer turbulence measurements at the Atmospheric Boundary Layer Experiments (ABLE) facility in Butler County, Kansas. These measurements and associated data were provided by a collection of instruments that included two 915 MHz wind profilers, two radio acoustic sounding systems, and two eddy correlation devices. The data from these devices were available through the Atmospheric Boundary Layer Experiment (ABLE) database operated by Argonne National Laboratory. A signal processing procedure outlined by Angevine et al. was adapted and further built upon to derive vertical velocity variance, {omega}'{sup 2}, from 915 MHz wind profiler measurements in the mixed layer. The proposed procedure consisted of the application of a height-dependent signal-to-noise ratio (SNR) filter, removal of outliers plus and minus two standard deviations about the mean on the spectral width squared, and removal of the effects of beam broadening and vertical shearing of horizontal winds. The scatter associated with {omega}'{sup 2} was mainly affected by the choice of SNR filter cutoff values. Several different sets of cutoff values were considered, and the optimal one was selected which reduced the overall scatter on {omega}'{sup 2} and yet retained a sufficient number of data points to average. A similarity relationship of {omega}'{sup 2} versus height was established for the mixed layer on the basis of the available data. A strong link between the SNR and growth/decay phases of turbulence was identified. Thus, the mid to late afternoon hours, when strong surface heating occurred, were observed to produce the highest quality signals.

  12. One year of vertical wind profiles measurements at a Mediterranean coastal site of South Italy

    NASA Astrophysics Data System (ADS)

    Calidonna, Claudia Roberta; Avolio, Elenio; Federico, Stefano; Gullì, Daniel; Lo Feudo, Teresa; Sempreviva, Anna Maria

    2015-04-01

    In order to develop wind farms projects is challenging to site them on coastal areas both onshore and offshore as suitable sites. Developing projects need high quality databases under a wide range of atmospheric conditions or high resolution models that could resolve the effect of the coastal discontinuity in the surface properties. New parametrizations are important and high quality databases are also needed for formulating them. Ground-based remote sensing devices such as lidars have been shown to be functional for studying the evolution of the vertical wind structure coastal atmospheric boundary layer both on- and offshore. Here, we present results from a year of vertical wind profiles, wind speed and direction, monitoring programme at a site located in the Italian Calabria Region, Central Mediterranean, 600m from the Thyrrenian coastline, where a Lidar Doppler, ZephIr (ZephIr ltd) has been operative since July 2013. The lidar monitors wind speed and direction from 10m up to 300m at 10 vertical levels with an average of 10 minutes and it is supported by a metmast providing: Atmospheric Pressure, Solar Radiation, Precipitation, Relative Humidity, Temperature,Wind Speed and Direction at 10m. We present the characterization of wind profiles during one year period according to the time of the day to transition periods night/day/night classified relating the local scale, breeze scale, to the large scale conditions. The dataset is also functional for techniques for short-term prediction of wind for the renewable energy integration in the distribution grids. The site infrastructure is funded within the Project "Infrastructure of High Technology for Environmental and Climate Monitoring" (I-AMICA) (PONa3_00363) by the Italian National Operative Program (PON 2007-2013) and European Regional Development Fund. Real-time data are show on http://www.i-amica.it/i-amica/?page_id=1122.

  13. Tropical Forest Biomass Estimation from Vertical Fourier Transforms of Lidar and InSAR Profiles

    NASA Astrophysics Data System (ADS)

    Treuhaft, R. N.; Goncalves, F.; Drake, J.; Hensley, S.; Chapman, B. D.; Michel, T.; Dos Santos, J. R.; Dutra, L.; Graca, P. A.

    2010-12-01

    Structural forest biomass estimation from lidar or interferometric SAR (InSAR) has demonstrated better performance than radar-power-based approaches for the higher biomasses (>150 Mg/ha) found in tropical forests. Structural biomass estimation frequently regresses field biomass to some function of forest height. With airborne, 25-m footprint lidar data and fixed-baseline C-band InSAR data over tropical wet forests of La Selva Biological Station, Costa Rica, we compare the use of Fourier transforms of vertical profiles at a few frequencies to the intrinsically low-frequency “average height”. RMS scatters of Fourier-estimated biomass about field-measured biomass improved by 40% and 20% over estimates base on average height from lidar and fixed-baseline InSAR, respectively. Vertical wavelengths between 14 and 100 m were found to best estimate biomass. The same airborne data acquisition over La Selva was used to generate many 10’s of repeat-track L-band InSAR baselines with time delays of 1-72 hours, and vertical wavelengths of 5-100 m. We will estimate biomass from the Fourier transforms of L-band radar power profiles (InSAR complex coherence). The effects of temporal decorrelation will be modeled in the Fourier domain to try to model and reduce their impact. Using L-band polarimetric interferometry, average heights will be estimated as well and biomass regression performance compared to the Fourier transform approach. The more traditional approach of using L-band radar polarimetry will also be compared to structural biomass estimation.

  14. Vertical profiles of optical and microphysical particle properties above the northern Indian Ocean during CARDEX 2012

    NASA Astrophysics Data System (ADS)

    Höpner, F.; Bender, F. A.-M.; Ekman, A. M. L.; Praveen, P. S.; Bosch, C.; Ogren, J. A.; Andersson, A.; Gustafsson, Ö.; Ramanathan, V.

    2015-02-01

    A detailed analysis of optical and microphysical properties of aerosol particles during the dry winter monsoon season above the northern Indian Ocean is presented. The Cloud Aerosol Radiative Forcing Experiment (CARDEX), conducted in February and March 2012 at the Maldives Climate Observatory on Hanimaadhoo island (MCOH) in the Republic of the Maldives, used autonomous unmanned aerial vehicles (AUAV) to perform vertical in-situ measurements of particle number concentration, particle number size distribution as well as particle absorption. These measurements were used together with surface-based Mini Micro Pulse Lidar (MiniMPL) observations and aerosol in-situ and off-line measurements to investigate the vertical distribution of aerosol particles. Air masses were mainly advected over the Indian subcontinent and the Arabian Peninsula. Mean surface aerosol number concentration was 1717±604 cm-3 and the highest values were found in air masses from the Bay of Bengal and Indo-Gangetic Plain (2247±370 cm-3). Investigations of the free tropospheric air showed that elevated aerosol layers with up to 3 times higher aerosol number concentrations than at the surface occurred mainly during periods with air masses originating from the Bay of Bengal and the Indo-Gangetic Plain. Compared to the Indian Ocean Experiment (INDOEX) conducted in winter 1999, elevated aerosol layers with increased aerosol number concentration were observed more frequently in 2012. However, lower particle absorption at the surface (σabs(520 nm)=8.5±4.2 Wm-1) was found during CARDEX compared to INDOEX 1999. By combining vertical in-situ measured particle absorption with scattering calculated with Mie-theory, layers with single-scattering albedo (SSA) values of specific source regions were derived and utilized to calculate vertical particle absorption profiles from MiniMPL profiles. SSA surface values for dry conditions were found to be 0.94±0.02 and 0.91±0.02 for air masses from the Arabian Sea (and

  15. Vertical profiles of optical and microphysical particle properties above the northern Indian Ocean during CARDEX 2012

    NASA Astrophysics Data System (ADS)

    Höpner, F.; Bender, F. A.-M.; Ekman, A. M. L.; Praveen, P. S.; Bosch, C.; Ogren, J. A.; Andersson, A.; Gustafsson, Ö.; Ramanathan, V.

    2016-01-01

    A detailed analysis of optical and microphysical properties of aerosol particles during the dry winter monsoon season above the northern Indian Ocean is presented. The Cloud Aerosol Radiative Forcing Experiment (CARDEX), conducted from 16 February to 30 March 2012 at the Maldives Climate Observatory on Hanimaadhoo island (MCOH) in the Republic of the Maldives, used autonomous unmanned aerial vehicles (AUAV) to perform vertical in situ measurements of particle number concentration, particle number size distribution as well as particle absorption coefficients. These measurements were used together with surface- based Mini Micro Pulse Lidar (MiniMPL) observations and aerosol in situ and off-line measurements to investigate the vertical distribution of aerosol particles.Air masses were mainly advected over the Indian subcontinent and the Arabian Peninsula. The mean surface aerosol number concentration was 1717 ± 604 cm-3 and the highest values were found in air masses from the Bay of Bengal and Indo-Gangetic Plain (2247 ± 370 cm-3). Investigations of the free tropospheric air showed that elevated aerosol layers with up to 3 times higher aerosol number concentrations than at the surface occurred mainly during periods with air masses originating from the Bay of Bengal and the Indo-Gangetic Plain. This feature is different compared to what was observed during the Indian Ocean Experiment (INDOEX) conducted in winter 1999, where aerosol number concentrations generally decreased with height. In contrast, lower particle absorption at the surface (σabs(520 nm) = 8.5 ± 4.2 Wm-1) was found during CARDEX compared to INDOEX 1999.Layers with source region specific single-scattering albedo (SSA) values were derived by combining vertical in situ particle absorption coefficients and scattering coefficients calculated with Mie theory. These SSA layers were utilized to calculate vertical particle absorption profiles from MiniMPL profiles. SSA surface values for 550 nm for dry

  16. ARM - Midlatitude Continental Convective Clouds Experiment (MC3E): Multi-Frequency Profilers, Vertical Air Motion (williams-vertair)

    DOE Data Explorer

    Williams, Christopher; Jensen, Mike

    2012-11-06

    This data was collected by the NOAA 449-MHz and 2.8-GHz profilers in support of the Department of Energy (DOE) and NASA sponsored Mid-latitude Continental Convective Cloud Experiment (MC3E). The profiling radars were deployed in Northern Oklahoma at the DOE Atmospheric Radiation Mission (ARM) Southern Great Plans (SGP) Central Facility from 22 April through 6 June 2011. NOAA deployed three instruments: a Parsivel disdrometer, a 2.8-GHz profiler, and a 449-MHz profiler. The parasivel provided surface estimates of the raindrop size distribution and is the reference used to absolutely calibrate the 2.8 GHz profiler. The 2.8-GHz profiler provided unattenuated reflectivity profiles of the precipitation. The 449-MHz profiler provided estimates of the vertical air motion during precipitation from near the surface to just below the freezing level. By using the combination of 2.8-GHz and 449-MHz profiler observations, vertical profiles of raindrop size distributions can be retrieved. The profilers are often reference by their frequency band: the 2.8-GHz profiler operates in the S-band and the 449-MHz profiler operates in the UHF band. The raw observations are available as well as calibrated spectra and moments. This document describes how the instruments were deployed, how the data was collected, and the format of the archived data.

  17. Can Vertical Profiles of Tropospheric Methane on Titan Be Derived from Radio-Occultation Soundings?

    NASA Technical Reports Server (NTRS)

    Flasar, F. Michael; Maroui, E. A.; Schinder, P. J.; French, R. G.; Rappaport, N. J.

    2010-01-01

    The intensity of the received signal at Earth in the radio occultations of Titan is attenuated both by refractive defocusing and pressure-induced absorption from N2-N2 and CH4-N2 pairs. Because the absorption strength is different for the two sets of pairs, matching the retrieved absorptivity profile can in principle yield the vertical variation in gaseous methane in the troposphere. There are two factors that make this difficult. The first is the propagation of noise in the phase and amplitude of the received signal in the absorption retrieval. The phase data is first inverted to retrieve vertical profiles of refractivity, from which the refractive defocusing is calculated. This is then subtracted from the observed. intensity attenuation of the received signal to generate a profile of atmospheric absorption. The second problem is the uncertainty in the pressure-induced absorption coefficients. Laboratory data at radio wavelengths is only available near room temperature (see, e.g., [1] for N2-N2), and the extrapolation to the low temperatures in Titan's troposphere is not well established. Ab initio calculations by Borysow et al. [2, 3] provide absorption coefficients at low temperatures and long wavelengths, but their accuracy has come into question. We present examples from Cassini radio occultations of Titan to illustrate the difficulties. For methane mole fractions in the lower troposphere comparable to that inferred from the Huygens probe (approximately 0.05), it will be difficult to separate the contributions of N2-N2 collisions from those of N2-CH4, collisions to the retrieved absorption. However, higher concentrations of CH4 and/or a higher signal-to-noise ratio from a future uplink experiment could result in a successful separation of the two components. However, key to this are highly accurate estimates of the absorption from a combination of laboratory measurements at love temperatures and long wavelengths, and possibly improved theoretical calculations.

  18. Vertical radar profiles for the calibration of unsaturated flow models under dynamic water table conditions

    NASA Astrophysics Data System (ADS)

    Cassiani, G.; Gallotti, L.; Ventura, V.; Andreotti, G.

    2003-04-01

    The identification of flow and transport characteristics in the vadose zone is a fundamental step towards understanding the dynamics of contaminated sites and the resulting risk of groundwater pollution. Borehole radar has gained popularity for the monitoring of moisture content changes, thanks to its apparent simplicity and its high resolution characteristics. However, cross-hole radar requires closely spaced (a few meters), plastic-cased boreholes, that are rarely available as a standard feature in sites of practical interest. Unlike cross-hole applications, Vertical Radar Profiles (VRP) require only one borehole, with practical and financial benefits. High-resolution, time-lapse VRPs have been acquired at a crude oil contaminated site in Trecate, Northern Italy, on a few existing boreholes originally developed for remediation via bioventing. The dynamic water table conditions, with yearly oscillations of roughly 5 m from 6 to 11 m bgl, offers a good opportunity to observe via VRP a field scale drainage-imbibition process. Arrival time inversion has been carried out using a regularized tomographic algorithm, in order to overcome the noise introduced by first arrival picking. Interpretation of the vertical profiles in terms of moisture content has been based on standard models (Topp et al., 1980; Roth et al., 1990). The sedimentary sequence manifests itself as a cyclic pattern in moisture content over most of the profiles. We performed preliminary Richards' equation simulations with time varying later table boundary conditions, in order to estimate the unsaturated flow parameters, and the results have been compared with laboratory evidence from cores.

  19. Seasonal and vertical distribution of Phyllophaga cuyabana (Moser)(Coleoptera: Melolonthidae) in the soil profile.

    PubMed

    Oliveira, Lenita J; Farias, José R B; Hoffmann-Campo, Clara B; Amaral, Maria L B do; Garcia, Maria A

    2009-01-01

    Phyllophaga cuyabana (Moser) temporal and vertical distribution patterns were evaluated in the soil profile, in order to subsidize methodology for population sampling, aiming at its management. In insect surveys carried out during three years, in Boa Esperança County, State of Parana, Brazil, Phyllophaga cuyabana was univoltine, with little overlap of the larval stages. Population peaked during December-February, but declined during the colder months, when larvae were in diapause. Different developmental stages exploited distinct soil depths. Eggs and early first instars tended to concentrate between 5 cm and 10 cm deep, but they spread more uniformly through the soil profile, reaching depths up to 30 cm, as they developed. Adults and eggs occurred in the spring (October to December) when active larvae also started to be observed; feeding larvae occurred up to late-April between 0 to 15 cm deep. Diapausing larvae and pupae were observed from early fall to early spring, mostly from 15 cm to 30 cm deep. Throughout the year, the number of insects in the soil (up to 40 cm deep) showed a positive functional relationship with air temperature and evapotranspiration. The relationship of percent distribution of larvae in the soil profile and soil temperature, however, was positive only above 10 cm. To estimate the insect population from November to April, samples can be collected until 20 cm deep; from May to October, however, samplings should be deeper, up to 30 cm.

  20. Evaluating the salinity distribution of a shallow coastal aquifer by vertical multielectrode profiling (Denmark)

    NASA Astrophysics Data System (ADS)

    Erbs Poulsen, Søren; Rømer Rasmussen, Keld; Bøie Christensen, Niels; Christensen, Steen

    2010-02-01

    A monitoring system, including five groups of piezometers and five vertical multielectrode profiling probes (VMEP), has been installed in an aquifer beneath a coastal dune in Denmark. In order to assess the salinity distribution within the aquifer, geoelectrical data were gathered in March, June and September 2008, by measuring a dipole-dipole and gradient array using multielectrode profiling. Interpretation of the processed resistivity data was performed by regularized inversion using a one-dimensional, horizontally layered model of formation resistivity. The standard deviation on estimated layer log-resistivity was 0.01-0.03. By estimating two parameters of a power function, observed fluid conductivities derived from samples of porewater were related to corresponding estimated formation resistivities. The conductivity profiles correlate with a winter situation in March with high sea level, active recharge and significant wave activity, causing increased hydraulic heads, a thicker freshwater lens and salt water overlying freshwater close to the sea. In June, the thickness of the freshwater lens is reduced due to less recharge and prevailing offshore winds, imposing density-stable conditions and a sharper transition between fresh and brackish water. During the autumn, aquifer recharge is enhanced and hydraulic heads increase, resulting in a thicker freshwater lens.

  1. Multiple Frequency Contrast Source Inversion Method for Vertical Electromagnetic Profiling: 2D Simulation Results and Analyses

    NASA Astrophysics Data System (ADS)

    Li, Jinghe; Song, Linping; Liu, Qing Huo

    2016-02-01

    A simultaneous multiple frequency contrast source inversion (CSI) method is applied to reconstructing hydrocarbon reservoir targets in a complex multilayered medium in two dimensions. It simulates the effects of a salt dome sedimentary formation in the context of reservoir monitoring. In this method, the stabilized biconjugate-gradient fast Fourier transform (BCGS-FFT) algorithm is applied as a fast solver for the 2D volume integral equation for the forward computation. The inversion technique with CSI combines the efficient FFT algorithm to speed up the matrix-vector multiplication and the stable convergence of the simultaneous multiple frequency CSI in the iteration process. As a result, this method is capable of making quantitative conductivity image reconstruction effectively for large-scale electromagnetic oil exploration problems, including the vertical electromagnetic profiling (VEP) survey investigated here. A number of numerical examples have been demonstrated to validate the effectiveness and capacity of the simultaneous multiple frequency CSI method for a limited array view in VEP.

  2. Algorithmic identification of limnological features in vertical profiles from the Great Lakes

    NASA Astrophysics Data System (ADS)

    Wietsma, T.; Collingsworth, P.; Minsker, B. S.

    2013-12-01

    High volume collection of environmental data in digital format presents a range of challenges for the researcher, from quality control and data management to efficient interpretation of the signal and the development of requisite information technology skills. These challenges have been termed the "data deluge". To aid in efficient data interpretation, we describe several algorithmic approaches for feature identification in signal streams, including gradient estimation, spectral analysis, and the hidden Markov model. These approaches are calibrated and evaluated over vertical temperature profiles from the Great Lakes obtained through the U.S. Environmental Protection Agency. To demonstrate the value of this data science approach, we describe how the algorithms can be integrated with the historical sampling record to yield an expert system that assists field technicians with adaptive sampling.

  3. Technique for Obtaining Vertical Profiles of Backscattering and Extinction Cross Sections Using Slant Path Lidar Measurements

    NASA Technical Reports Server (NTRS)

    Spinhirne, J. D.; Herman, B. M.

    1973-01-01

    A method is presented for solving for vertical profiles of atmospheric particulate extinction and backscattering cross-sections utilizing monostatic lidar slant path measurements. The method is an extension of work by Fernald. It is shown that the number of assumptions necessary for an iterative solution of extinction and backscattering cross sections can be reduced if lidar slant path measurements are used to solve directly for optical depths. The technique is useful only if sufficiently accurate lidar measurements are available. With highly accurate measurements it is also possible to solve directly for extinction cross sections without an iterative solution of a transcendental equation if the proper reduction scheme is used. The required accuracy is discussed and results showing the effect of errors are presented.

  4. Assessment of an Antrim Oil Shale fracture zone by vertical seismic profiling

    SciTech Connect

    Toksoez, M.N.; Turpening, R.M.; Stewart, R.R.

    1980-09-01

    This report presents the results of a vertical seismic profiling (VSP) experiment performed in the upper 2500 feet (770 m) of the Michigan Basin. Both P and SH waves were used. The experiment was divided into two parts: a before survey run on the virgin rock, then an after survey across an explosively fractured volume of Antrim Oil Shale, centered at 1300 ft (400 m). From the before VSP survey, a velocity structure of the basin was calculated. Comparison of the after observations to the before elucidated the fracture volume and elastic parameters. Travel time delays, amplitude attenuation, converted and diffracted waves provided consistent information on the depth (1300 ft), shape (ellipsoid) and size (10 m x 20 m x 30 m) of the fractured volume.

  5. An Algorithm to Estimate the Heating Budget from Vertical Hydrometeor Profiles.

    NASA Astrophysics Data System (ADS)

    Tao, Wei-Kuo; Simpson, Joanne; Lang, Stephen; McCumber, Michael; Adler, Robert; Penc, Richard

    1990-12-01

    A simple algorithm to estimate the latent heating of cloud systems from their vertical hydrometer profiles is proposed. The derivation as well as the validation of the algorithm is based on output generated by a non-hydrostatic cloud model with parameterized microphysical processes. Mature and decaying stages of a GATE squall-type convective system have been tested. The algorithm-derived heating budget is in reasonable agreement with the budget predicted by the cloud model. The input to the proposed algorithm can be obtained from either a rain retrieval technique based on information from multichannel passive microwave signals or a kinematic cloud model based on information from Doppler radar wind fields and radar reflectivity patterns. Such an application would have significant implications for spaceborne remote sensing and the large-scale weather prediction data assimilation problem.

  6. Characterizing leaf area index (LAI) and vertical foliage profile (VFP) over the United States

    NASA Astrophysics Data System (ADS)

    Tang, H.; Ganguly, S.; Zhang, G.; Hofton, M. A.; Nelson, R. F.; Dubayah, R.

    2016-01-01

    Leaf area index (LAI) and vertical foliage profile (VFP) are among the important canopy structural variables. Recent advances in lidar remote sensing technology have demonstrated the capability of accurately mapping LAI and VFP over large areas. The primary objective of this study was to derive and validate a LAI and VFP product over the contiguous United States (CONUS) using spaceborne waveform lidar data. This product was derived at the footprint level from the Geoscience Laser Altimeter System (GLAS) using a biophysical model. We validated GLAS-derived LAI and VFP across major forest biomes using airborne waveform lidar. The comparison results showed that GLAS retrievals of total LAI were generally accurate with little bias (r2 = 0.67, bias = -0.13, RMSE = 0.75). The derivations of GLAS retrievals of VFP within layers were not as accurate overall (r2 = 0.36, bias = -0.04, RMSE = 0.26), and these varied as a function of height, increasing from understory to overstory - 0 to 5 m layer: r2 = 0.04, bias = 0.09, RMSE = 0.31; 10 to 15 m layer: r2 = 0.53, bias = -0.08, RMSE = 0.22; and 15 to 20 m layer: r2 = 0.66, bias = -0.05, RMSE = 0.20. Significant relationships were also found between GLAS LAI products and different environmental factors, in particular elevation and annual precipitation. In summary, our results provide a unique insight into vertical canopy structure distribution across North American ecosystems. This data set is a first step towards a baseline of canopy structure needed for evaluating climate and land use induced forest changes at the continental scale in the future, and should help deepen our understanding of the role of vertical canopy structure in terrestrial ecosystem processes across varying scales.

  7. Characterizing Leaf Area Index (LAI) and Vertical Foliage Profile (VFP) over the United States

    NASA Astrophysics Data System (ADS)

    Tang, H.; Ganguly, S.; Zhang, G.; Hofton, M. A.; Nelson, R. F.; Dubayah, R.

    2015-08-01

    Leaf area index (LAI) and vertical foliage profile (VFP) are among the important canopy structural variables. Recent advances in lidar remote sensing technology have demonstrated the capability of accurately mapping LAI and VFP over large areas. The primary objective of this study was to derive and validate a LAI and VFP product over the contiguous United States using spaceborne waveform lidar data. This product was derived at the footprint level from the Geoscience Laser Altimeter System (GLAS) using a biophysical model. We validated GLAS derived LAI and VFP across major forest biomes using airborne waveform lidar. The comparison results showed that GLAS retrievals of total LAI were generally accurate with little bias (r2 = 0.67, bias = -0.13, RMSE = 0.75). The derivations of GLAS retrievals of VFP within layers was not as accurate overall (r2 = 0.36, bias = -0.04, RMSE = 0.26), and these varied as a function of height, increasing from understory to overstory -0 to 5 m layer: r2 = 0.04, bias = 0.09, RMSE = 0.31; 10 to 15 m layer: r2 = 0.53, bias = -0.08, RMSE = 0.22; and 15 to 20 m layer: r2 = 0.66, bias =-0.05, RMSE = 0.20. Significant relationships were also found between GLAS LAI products and different environmental factors, in particular elevation and annual precipitation. In summary, our results provide a unique insight into vertical canopy structure distribution across North American ecosystems. This data set is a first step towards a baseline of canopy structure needed for evaluating climate and land use induced forest changes at continental scale in the future and should help deepen our understanding of the role of vertical canopy structure on terrestrial ecosystem processes across varying scales.

  8. Computation of vertical profiles of longwave radiative cooling over the equatorial Pacific

    NASA Technical Reports Server (NTRS)

    Ramsey, Perry G.; Vincent, Dayton G.

    1995-01-01

    An important quantity whose magnitude has not been throughly examined is the vertical distribution of heating in the Tropics. The details of the vertical distribution of heating have a significant impact on a number of phenomena, including the 30-60 day oscillation, sometimes known as the intraseasonal oscillation. Prior attempts to establish the structure of the heating relied on limited field data or assimilated data, coupled with climatological radiative heating parameters. The availability of high quality global-scale datasets has made it possible to make more accurate calculations than were possible a few years ago. An important component of the apparent heat budget is the longwave radiative cooling, which in this paper is found by using the ECMWF/WCRP/TOGA Archive 2 and ISCCP C1 datasets, together with a well-established parameterization scheme. A method is developed that can be used to estimate the vertical structure of cloud amounts based on top-of-atmosphere cloud observations, and the results are used with a wide-band longwave parameterization to produce longwave cooling rates over the tropical Pacific Ocean. Outgoing longwave radiation is calculated and compared the ERBE results. The calculated values are generally higher than those from ERBE, though the spatial distributions are similar. Some significant problems exist with the ECMWF upper-tropospheric water vapor amounts, which could imply uncertainties of 0.5 C/day in the calculated cooling rates. This is comparable to the differences associated with the minimum or random overlap assumptions used to generate cloud profiles.

  9. 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

  10. Vertical Profiles of Latent Heating in TRMM: Validation and Assimilation in the GEOS Data Assimilation System. [Year 2001 Project Report

    NASA Technical Reports Server (NTRS)

    Zhang, Ming-Hua

    2001-01-01

    I have derived the vertical profiles of apparent heating Q and Q2 by using 3-hourly balloon sounding data from the ARM SGP sounding array for three IOPs in 2000. These IOPs cover the periods from 3/1 to 3/22, from 9/25 to 10/8, and from 11/27 to 12/22. These heating profiles will be collocated with the TRMM heating profiles for validation studies once the TRMM profiles become available to the investigators. I have also produced the objective analyses of Q1, Q2 and forcing fields for the international GCSS Case 3 Intercomparison project. The GSFC CRM participated in study, based on which TRMM heating profiles are derived. I have also studied to assimilate the vertical heating profile by constraining the cloud-base mass flux in the cumulus convection scheme using the CCM3. I first derive the vertical heating profile for each convective plume of unit cloud-base mass flux. The observed heating profile form ARM is then de-convoluted to derive the cloud base mass fluxes of all individual plumes. These fluxes are compared with those derived from the quasi-equilibrium hypothesis. They are shown to improve many other aspects of the model behavior.

  11. An evaluation and comparison of vertical profile data from the VISSR Atmospheric Sounder (VAS)

    NASA Technical Reports Server (NTRS)

    Jedlovec, G. J.

    1985-01-01

    A statistical evaluation is used to compared vertical profiles of temperature and moisture derived from VISSR Atmospheric Sounder (VAS) with three different algorithms to that of corresponding rawinsonde measurements for a clear cold environment. To account for time and space discrepancies between the data sets, rawinsonde data were adjusted to be representative of the satellite sounding times. Both rawinsonde and satellite sounding data were objectively analyzed onto a mesoscale grid. These grid point values were compared at 50 mb pressure increments from the surface up to 100 mb. The data were analyed for horizontal and vertical structure, representatives of derived parameters, and significant departure (improvement) from the apriori (first guess) information. Results indicate some rather strong temperature and moisture biases exist in the satellite soundings. Temperature biases of 1 to 4 C and dewpoint biases of 2 to 6 C generally occur in layers where strong inversions are present and vary with time as these atmospheric features evolve. The biases also changes as a function retrieval scheme suggesting limitations and restrictions on the applications of the various techniques. Standard temperature deviations range from 1 to 2 C for each retrieval scheme with maximum values around 800 and 400 mb. Derived parameters (precipitable water and thickness) suffer from similar biases, though to a somewhat lesser extent. Gradients of basic and derived parameters are generally weaker but have good horizontal structure where magnitudes of the parameters are relatively strong. Integrated thermal (temperature) and moisture (precipitable water) parameters show mixed results.

  12. Use of vertical electrical resistivity profiles to characterize the riverbed of losing-disconnected rivers

    NASA Astrophysics Data System (ADS)

    Lamontagne, Sebastien; Davis, Aaron; Crosbie, Russell; Taylor, Andrew; Munday, Tim

    2014-05-01

    There are few field techniques available to estimate infiltration rates from losing-disconnected rivers, where infiltration rates are often constrained by the presence of clay layers with a low hydraulic conductivity. It is hypothesized that, in this environment, the bulk of the infiltration would occur in 'hotspots' where the clay layer is thin or absent. Infiltration was estimated over a 2 km section of Billabong Creek (Murray-Darling Basin, Australia) using vertical electrical sounding (VES) resistivity to characterize the continuity and thickness of the riverbed clay layer. Both a towed in-river survey over the whole study reach and three fixed array measurements at the shoreline at selected areas were used. Using locations with measured high and low resistivity, the resistivity profiles were constrained by coring the riverbed to measure vertical variations in riverbed texture, porewater content and porewater salinity. The VES showed that the clay layer was continuous along the study reach and varied in thickness between 1 m and >4 m. Using a simple steady-state model, infiltration rates along the study reach were estimated to vary between 1700 and 7800 m3 km-1 year-1, with an average of 3400 m3 km-1 year-1. This methodology can provide independent estimates of infiltration rates at a scale suitable for the calibration of regional groundwater models.

  13. Total fluoride in Guangdong soil profiles, China: spatial distribution and vertical variation.

    PubMed

    Zhu, L; Zhang, H H; Xia, B; Xu, D R

    2007-04-01

    A total of 260 soil profiles were reported to investigate the fluoride distribution and vertical variation in Guangdong province. The soil fluoride contents followed an approximately lognormal distribution. Although the soil fluoride geometric mean concentration of 407 mg/kg is lower than that of China, its content varied from 87 to 2860 mg/kg. An upper baseline concentration of 688 mg/kg was estimated for surface soils. In A-, B-, and C-horizon soil fluoride spatial distribution presented similar patterns that high fluoride concentration mainly located in limestone, purple shale, and sandshale areas, indicated that soil fluoride spatial distribution was primarily dependent on the regional bedrock properties rather than anthropogenic inputs. From A- to C- horizon soil fluoride geometric mean concentration had an increasing tendency of 407, 448, and 465 mg/kg. This vertical variation was the result of the intensive eluviation under the subtropical hydrothermal condition, and had closely related with soil properties, such as lower organic matters and clay content variations. Moreover, the soil degradation and erosion was also an important pathway of soil fluoride movement, as a result the soil fluoride exported into surface and groundwaters would reach about 4.1x10(4) t year-1 in the study area.

  14. Vertical profile of δ18OOO from the middle stratosphere to lower mesosphere from SMILES spectra

    NASA Astrophysics Data System (ADS)

    Sato, T. O.; Sagawa, H.; Yoshida, N.; Kasai, Y.

    2014-04-01

    Ozone is known to have large oxygen isotopic enrichments of about 10% in the middle stratosphere; however, there have been no reports of ozone isotopic enrichments above the middle stratosphere. We derived an enrichment δ18OOO in the stratosphere and the lower mesosphere from observations of the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) onboard the International Space Station (ISS) using a retrieval algorithm optimized for the isotopic ratio. The retrieval algorithm includes (i) an a priori covariance matrix constrained by oxygen isotopic ratios in ozone, (ii) an optimization of spectral windows for ozone isotopomers and isotopologues, and (iii) common tangent height information for all windows. The δ18OOO by averaging the SMILES measurements at the latitude range of 20 to 40° N from February to March in 2010 with solar zenith angle < 80° was 13% (at 32 km) with the systematic error of about 5%. SMILES and past measurements were in good agreement, with δ18OOO increasing with altitude between 30 and 40 km. The vertical profile of δ18OOO obtained in this study showed an increase and a decrease with altitude in the stratosphere and mesosphere, respectively. The δ18OOO peak, 18%, is found at the stratopause. The δ18OOO has a positive correlation with temperature in the range of 220-255 K, indicating that temperature can be a dominant factor to control the vertical profile of δ18OOO in the stratosphere and mesosphere. This is the first report of the observation of δ18OOO over a wide altitude range extending from the stratosphere to the mesosphere (28-57 km).

  15. Development of ATLID-MSI synergy for retrieving the vertical profiles of aerosol components

    NASA Astrophysics Data System (ADS)

    Kudo, R.; Nishizawa, T.; Higurashi, A.; Sugimoto, N.; Oikawa, E.

    2014-12-01

    EarthCARE is an earth observation satellite and will be launched in 2016. Using its two sensors, ATLID (High spectral resolution lidar) and MSI (Multi-spectral imager), we are developing the synergy algorithm to retrieve the vertical profiles of extinction coefficients at 355 nm of four aerosol components (Water-soluble, black carbon, dust, and sea-salt particles), and the column mean of mode radii of water-soluble and dust particles. The ATLID data are extinction coefficient, backscatter coefficient, and depolarization ratio for total aerosols at 355 nm. The MSI data are radiances at 670 and 865 nm. The dry volume concentrations of four aerosol components at each altitude and the mode radii of water-soluble and dust particles in the column are simultaneously optimized to ATLID and MSI data by the gauss newton method. After the optimization, the vertical profiles of the extinction coefficient at 355 nm of four aerosol components are obtained. The size distributions of four aerosol components are assumed to be a lognormal distribution. The refractive indices of four aerosol components are given from previously observational studies. The humidity growth is considered for water-soluble and sea-salt particles. The volume concentration and the mode radius of the sea-salt particle are parameterized using the surface wind speed on the ocean. We assumed that the shape of the water-soluble, black carbon, and sea-salt particles are spherical, and the shape of the dust particle is spheroidal. We tested the algorithm using the ATLID and MSI data simulated using clean, dust-transported, and smoke-transported aerosols. The extinction coefficients of each component at 355 nm are retrieved well. The mode radius of water-soluble and dust particles were somehow overestimated.

  16. Vertical Profiles of SO2 and NO2 in the Alberta Oil Sands: MAX-DOAS Measurements and Comparison to in-situ Instrumentation

    NASA Astrophysics Data System (ADS)

    Davis, Zoe; Lobo, Akshay; McLaren, Robert

    2015-04-01

    complex (e.g. elevated layers). Retrieved trace gas vertical profiles were compared with aircraft composite profiles from flights over the site. Trace gas surface retrievals were compared with results from a co-located active-DOAS instrument. The degree of agreement between the DOAS instruments appear to be related to pollution levels and meteorological conditions. Significant observed pollution events were associated with particular meteorological conditions such as South-Westerly winds. Maximum observed SO2 and NO2 retrieved mixing ratios were 250ppb and 60ppb, respectively, at approximately 300m above the surface while maximum surface concentrations measured by the active-DOAS were 77ppb and 20 ppb, respectively. The observed spatial complexity in the trace gas profiles indicates that comprehensive air quality monitoring in the oil sands requires instruments with boundary layer spatial profiling capabilities.

  17. Using the IODP Expedition 312 Vertical Seismic Profile to Investigate Sub-basement Reflections in Multi-Channel Profiles

    NASA Astrophysics Data System (ADS)

    Nag, S.; Swift, S. A.; Stephen, R. A.

    2008-05-01

    The Ocean Drilling Program (ODP) initiated drilling at Site 1256D in the Guatemala Basin, about 1000km off the East Pacific Rise to penetrate plutonic rocks, anticipated to be relatively shallow in this region formed at an ultra- fast spreading rate. IODP Expedition E312 successfully drilled into gabbros at ~ 1150m in basement. Multi- channel seismic traces, although not processed for the purpose, show weak laterally-coherent sub-basement reflections at borehole depths (Hallenborg et. al., Journal of Geophysical Research, Vol 108 No. B11, 2532, 2003). Synthetic reflectivity seismograms were computed using a Ricker wavelet and impedance profiles from borehole sonic logs. They strongly suggest the presence of significant sub-basement amplitude peaks - although attenuation has not been modeled. Zero-offset vertical seismic profiles were processed to investigate the authenticity of these reflections and interpret the geological features that caused them. A dual scheme of the median filtering and F-K dip filtering was used. Down-going energy is clearly identified but negligible up-going energy is visible over random noise. The absence of geophones above the basement prevents comparison of basement reflections with sub-basement ones, so that a critical energy level above the noise could be established to identify up-going energy. The negative results are consistent with the topography of geological horizons on horizontal scales less than the Fresnel Zone (~ 300m). This expedition is the first penetration through volcanic extrusives and dikes into plutonic basement. In such a setting, sub-basement reflections, if present, would have been accurately measured. Absence of such clear and comprehensible observations in this area strongly suggests that lava flows and igneous contacts in upper ocean crust have significant topography on lateral scales < 300 m due to igneous and tectonic processes.

  18. An investigation into the vertical axis control power requirements for landing VTOL type aircraft onboard nonaviation ships in various sea states

    NASA Technical Reports Server (NTRS)

    Stevens, M. E.; Roskam, J.

    1985-01-01

    The problem of determining the vertical axis control requirements for landing a VTOL aircraft on a moving ship deck in various sea states is examined. Both a fixed-base piloted simulation and a nonpiloted simulation were used to determine the landing performance as influenced by thrust-to-weight ratio, vertical damping, and engine lags. The piloted simulation was run using a fixed-based simulator at Ames Research center. Simplified versions of an existing AV-8A Harrier model and an existing head-up display format were used. The ship model used was that of a DD963 class destroyer. Simplified linear models of the pilot, aircraft, ship motion, and ship air-wake turbulence were developed for the nonpiloted simulation. A unique aspect of the nonpiloted simulation was the development of a model of the piloting strategy used for shipboard landing. This model was refined during the piloted simulation until it provided a reasonably good representation of observed pilot behavior.

  19. Comparing Water Vapor Mixing Ratio Profiles and Cloud Vertical Structure from Multiwavelength Raman Lidar Retrievals and Radiosounding Measurements

    NASA Astrophysics Data System (ADS)

    Costa-Surós, Montserrat; Stachlewska, Iwona S.; Markowicz, Krzysztof

    2016-06-01

    A study of comparison of water vapor mixing ratio profiles, relative humidity profiles, and cloud vertical structures using two different instruments, a multiwavelength Aerosol-Depolarization-Raman lidar and radiosoundings, is presented. The observations were taken by the lidar located in Warsaw center and the radiosoundings located about 30km to the North in Legionowo (Poland). We compared the ground-based remote sensing technology with in-situ method in order to improve knowledge about water content thought the atmosphere and cloud formation. The method used for retrieving the cloud vertical structure can be improved comparing the radiosonde results with the lidar observations, which show promising results.

  20. Vertical profiles of aerosol volume from high-spectral-resolution infrared transmission measurements. I. Methodology.

    PubMed

    Eldering, A; Irion, F W; Chang, A Y; Gunson, M R; Mills, F P; Steele, H M

    2001-06-20

    The wavelength-dependent aerosol extinction in the 800-1250-cm(-1) region has been derived from ATMOS (atmospheric trace molecule spectroscopy) high-spectral-resolution IR transmission measurements. Using models of aerosol and cloud extinction, we have performed weighted nonlinear least-squares fitting to determine the aerosol-volume columns and vertical profiles of stratospheric sulfate aerosol and cirrus cloud volume. Modeled extinction by use of cold-temperature aerosol optical constants for a 70-80% sulfuric-acid-water solution shows good agreement with the measurements, and the derived aerosol volumes for a 1992 occultation are consistent with data from other experiments after the eruption of Mt. Pinatubo. The retrieved sulfuric acid aerosol-volume profiles are insensitive to the aerosol-size distribution and somewhat sensitive to the set of optical constants used. Data from the nonspherical cirrus extinction model agree well with a 1994 mid-latitude measurement indicating the presence of cirrus clouds at the tropopause.

  1. Vertical geochemical profiling of an aquifer contaminated with JP-4 fuel

    SciTech Connect

    Fang, Jiasong; Barcelona, M.J.

    1996-12-31

    Soil samples were collected at a site contaminated with jet fuel at Wurtsmith Air Force Base, Michigan, and were analyzed for aromatic hydrocarbons, aromatic acid metabolites, and phospholipid ester-linked fatty acids (PLFA). Vertically in the source zone contaminant concentrations of alkylbenzenes (with C1-C4 substitutions) ranged from less than 1.0 to 21.69 {mu}g/kg away from water table to 2605.96 {mu}g/kg in samples taken at water table. Contamination decreased to less than 1.0 {mu}g/kg in downgradient zone. Aromatic acids of the fuel contaminants identified include o-, m-, and p-toluic acid, 2,5-, 3,5-, 2,6- and 3,4-dimethylbenzoic acid, and 2,4,6-trimethylbenzoic acid, suggesting that the aromatic acid production was associated with the microbial degradation of aromatic hydrocarbons. PLFA ranging from C{sub 12} to C{sub 20} were determined in soil samples, including saturated and monounsaturated fatty acids. The only polyenic acid detected was 18:2w6, a biomarker for protozoa. The total microbial biomass calculated from PLFA in aquifer solid samples showed varied profiles with depth as well as at different locations at similar depths indicating considerable microbial heterogeneity in the subsurface over distance of less than 2 meters. The PLFA profiles also suggested that anaerobic and aerobic microbial communities dominate the biomass in the aquifer solids.

  2. Vertical Profiles of NOx, O3, and Volatile Organic Compounds in a Deciduous Forest Canopy

    NASA Astrophysics Data System (ADS)

    Jobson, B. T.; Wallace, H. W.; Erickson, M. H.; Pressley, S. N.; Rausch, J. L.; O'Donnell, K.

    2010-12-01

    Vertical profiles of traces gases were made through a deciduous forest canopy as part of the Community Atmosphere-Biosphere Interactions Experiments (CABINEX) conducted in July-August, 2009 at the University of Michigan Biological Station. Measurements of O3, NO, NO2 and VOCs were made from three heights: 6 m, the top of the forest canopy at 20 m, and at a height of 34 m. O3 was continuously monitored from each of these heights. NOx and VOC measurements switched between these sampling heights every 10 minutes. VOCs were measured using a Proton Transfer Reaction Mass Spectrometer (PTR-MS). Measured VOCs include formaldehyde and methylhydroperoxide as well as isoprene and monoterpenes. NO and NO2 were continuously measured using a two channel chemiluminescent instrument. NOx mixing ratios were often significantly greater at the 6 m sampling height compared to the top of the canopy, suggesting NOx emissions from the forest floor. A difference of 50 pptv or greater was measured 44% of the time and frequently observed at night and during the morning. Approximately 40% of the time the differences were less than 10 pptv, implying a well mixed environment. The NOX and VOC profiles and their diel behavior will be presented to illustrate the importance of surface sources and sinks on trace gas mixing ratios within a forest canopy.

  3. Analytical solution for the vertical profile of daily production in the ocean

    NASA Astrophysics Data System (ADS)

    Kovač, Žarko; Platt, Trevor; Sathyendranath, Shubha; Morović, Mira

    2016-05-01

    Photosynthesis parameters are routinely estimated from in vitro measurements of primary production under constant light reaching each incubation bottle, by fitting a photosynthesis-irradiance function to the measurements. Here we take one such function and integrate it in time for variable light input, similar to natural conditions, to obtain the analytical solution for the vertical profile of daily phytoplankton production in the field. This solution is then fitted to in situ measurements of primary production profiles in the same manner as a photosynthesis-irradiance function is fitted to in vitro measurements under controlled and constant light conditions to retrieve the photosynthesis-irradiance parameters. The method is tested on the Hawaii Ocean Time-series data set. The solution explained 97.88% of the variance in measured normalized production at individual depths. The recovered parameters were then used to model the normalized daily water-column production. The model explained 99.21% of variance in normalized watercolumn production of the entire data set. The seasonal cycle of the photosynthesis parameters recovered with the analytical solution was further studied for the Hawaii Ocean Time-series. With respect to the photosynthesis parameter determination, the solution bridges the gap between classical photosynthesis-irradiance measurements under controlled light conditions and in situ measurements which are made under natural, variable light conditions. It presents a new tool for the estimation of photosynthesis parameters from in situ measurements of primary production.

  4. Comparing the Cloud Vertical Structure Derived from Several Methods Based on Radiosonde Profiles and Ground-based Remote Sensing Measurements

    SciTech Connect

    Costa-Suros, M.; Calbo, J.; Gonzalez, J. A.; Long, Charles N.

    2014-08-27

    The cloud vertical distribution and especially the cloud base height, which is linked to cloud type, is an important characteristic in order to describe the impact of clouds in a changing climate. In this work several methods to estimate the cloud vertical structure (CVS) based on atmospheric sounding profiles are compared, considering number and position of cloud layers, with a ground based system which is taken as a reference: the Active Remote Sensing of Clouds (ARSCL). All methods establish some conditions on the relative humidity, and differ on the use of other variables, the thresholds applied, or the vertical resolution of the profile. In this study these methods are applied to 125 radiosonde profiles acquired at the ARM Southern Great Plains site during all seasons of year 2009 and endorsed by GOES images, to confirm that the cloudiness conditions are homogeneous enough across their trajectory. The overall agreement for the methods ranges between 44-88%; four methods produce total agreements around 85%. Further tests and improvements are applied on one of these methods. In addition, we attempt to make this method suitable for low resolution vertical profiles, which could be useful in atmospheric modeling. The total agreement, even when using low resolution profiles, can be improved up to 91% if the thresholds for a moist layer to become a cloud layer are modified to minimize false negatives with the current data set, thus improving overall agreement.

  5. Relationships among cloud occurrence frequency, overlap, and effective thickness derived from CALIPSO and CloudSat merged cloud vertical profiles

    NASA Astrophysics Data System (ADS)

    Kato, Seiji; Sun-Mack, Sunny; Miller, Walter F.; Rose, Fred G.; Chen, Yan; Minnis, Patrick; Wielicki, Bruce A.

    2010-01-01

    A cloud frequency of occurrence matrix is generated using merged cloud vertical profiles derived from the satellite-borne Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and cloud profiling radar. The matrix contains vertical profiles of cloud occurrence frequency as a function of the uppermost cloud top. It is shown that the cloud fraction and uppermost cloud top vertical profiles can be related by a cloud overlap matrix when the correlation length of cloud occurrence, which is interpreted as an effective cloud thickness, is introduced. The underlying assumption in establishing the above relation is that cloud overlap approaches random overlap with increasing distance separating cloud layers and that the probability of deviating from random overlap decreases exponentially with distance. One month of Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) and CloudSat data (July 2006) support these assumptions, although the correlation length sometimes increases with separation distance when the cloud top height is large. The data also show that the correlation length depends on cloud top hight and the maximum occurs when the cloud top height is 8 to 10 km. The cloud correlation length is equivalent to the decorrelation distance introduced by Hogan and Illingworth (2000) when cloud fractions of both layers in a two-cloud layer system are the same. The simple relationships derived in this study can be used to estimate the top-of-atmosphere irradiance difference caused by cloud fraction, uppermost cloud top, and cloud thickness vertical profile differences.

  6. Vertical profiling of methane and carbon dioxide using high resolution near-infrared heterodyne spectroscopic observations

    NASA Astrophysics Data System (ADS)

    Rodin, Alexander; Klimchuk, Artem; Churbanov, Dmitry; Pereslavtseva, Anastasia; Spiridonov, Maxim; Nadezhdinskyi, Alexander

    2014-05-01

    We present new method of monitoring greenhouse gases using spectroscopic observations of solar radiation passed through the atmosphere with spectral resolution ΛvδΛ up to 108. Such a high resolution is achieved by heterodyne technique and allows to retrieve full information about spectral line shape which, in turn, is used to distinguish contribution of different atmospheric layers to the resulting absorption. Weak absorption line at 6056.5 cm-1 was selected for CO2 measurements and a quartet of lines centered at 6057 cm-1for CH4. The instrument setup includes Sun tracker with a microtelescope and chopper, diode DFB laser used as a local oscillator, a bundle of single mode optical fibers that provides medium for radiation transfer and beam coupling, reference cell with depressurized methane for LO frequency stabilization, and Fabry-Perot etalon for LO frequency calibration. A commercial p-i-n diode with squared detector replaces a mixer and IF spectrometer, providing measurement of heterodyne beating within a bandpass of few MHz, which determines the effective spectral resolution of the instrument. Spectral coverage within narrow range (about 1 cm-1) is provided by ramping the LO frequency based on feedback from the reference channel. Observations of Sun in the Moscow region have resulted for the first time in measurements of the atmospheric transmission near 1.65 μm with sub-Doppler spectral resolution. In order to retrieve vertical profiles of methane and carbon dioxide we developed the inversion algorithm implementing Tikhonov regularization approach. With measured transmission having S/N ratio of 100 or higher, the uncertainty of CH4 profile is about 10 ppb, with the uncertainty of CO2 profile at 1 ppm. This techniques is promising an affordable opportunity or widespread monitoring of greenhouse gases and may be implemented on existing ground-based stations. This work has been supported by the grant of Russian Ministry of education and science #11.G34.31.0074

  7. AROTAL Ozone and Temperature Vertical Profile Measurements from the NASA DC-8 during the SOLVE II Campaign

    NASA Technical Reports Server (NTRS)

    McGee, Thomas J.; Twigg, Laurence; Sumnicht, Grant; Hoegy, Walter; Burris, John; Silbert, Donald; Heaps, William; Neuber, R.; Trepte, C. R.

    2004-01-01

    The AROTAL instrument (Airborne Raman Ozone Temperature and Aerosol Lidar) - a collaboration between scientists at NASA Goddard Space Flight Center, and Langley Research Center - was flown on the NASA DC-8 during the SOLVE II Campaign during January and February, 2003. The flights were flown from the Arena Arctica in Kiruna, Sweden. We report measurements of temperature and ozone profiles showing approximately a 600 ppbv loss in ozone near 17.5 km, over the time frame of the aircraft campaign. Comparisons of ozone profiles from AROTAL are made with the SAGE III instrument.

  8. Improvement of vertical profiles of raindrop size distribution from micro rain radar using 2D video disdrometer measurements

    NASA Astrophysics Data System (ADS)

    Adirosi, E.; Baldini, L.; Roberto, N.; Gatlin, P.; Tokay, A.

    2016-03-01

    A measurement scheme aimed at investigating precipitation properties based on collocated disdrometer and profiling instruments is used in many experimental campaigns. Raindrop size distribution (RSD) estimated by disdrometer is referred to the ground level; the collocated profiling instrument is supposed to provide complementary estimation at different heights of the precipitation column above the instruments. As part of the Special Observation Period 1 of the HyMeX (Hydrological Cycle in the Mediterranean Experiment) project, conducted between 5 September and 6 November 2012, a K-band vertically pointing micro rain radar (MRR) and a 2D video disdrometer (2DVD) were installed close to each other at a site in the historic center of Rome (Italy). The raindrop size distributions collected by 2D video disdrometer are considered to be fairly accurate within the typical sizes of drops. Vertical profiles of raindrop sizes up to 1085 m are estimated from the Doppler spectra measured by the micro rain radar with a height resolution of 35 m. Several issues related to vertical winds, attenuation correction, Doppler spectra aliasing, and range-Doppler ambiguity limit the performance of MRR in heavy precipitation or in convection, conditions that frequently occur in late summer or in autumn in Mediterranean regions. In this paper, MRR Doppler spectra are reprocessed, exploiting the 2DVD measurements at ground to estimate the effects of vertical winds at 105 m (the most reliable MRR lower height), in order to provide a better estimation of vertical profiles of raindrop size distribution from MRR spectra. Results show that the reprocessing procedure leads to a better agreement between the reflectivity computed at 105 m from the reprocessed MRR spectra and that obtained from the 2DVD data. Finally, vertical profiles of MRR-estimated RSDs and their relevant moments (namely median volume diameter and reflectivity) are presented and discussed in order to investigate the

  9. Merging OSIRIS, SAGE II and MLS Vertical Ozone Profiles for the Determination of Long Term Trends

    NASA Astrophysics Data System (ADS)

    Degenstein, D. A.; Lloyd, N.; Bourassa, A. E.; Roth, C.; Rieger, L. A.

    2015-12-01

    The OSIRIS instrument has been in operation onboard the Odin spacecraft since the autumn of 2001. Since that time OSIRIS has routinely measured spectrally dispersed limb-scattered sunlight from which vertical ozone profiles have been derived. The length of the OSIRIS ozone data record makes it a valuable resource for the analysis of long term trends. However, on its own it is not of sufficient length to capture all of the relevant signatures required to completely understand important changes in the vertical distribution of ozone. In particular the 1997 turnaround is not captured within the OSIRIS time series. For this reason it is important that the OSIRIS measurements be combined, or merged, with other data records like the SAGE II time series before a full analysis can be performed. This paper is focused on the merged SAGE II - OSIRIS time series and the resulting trends. It has been recently noted that the post 1997 positive trends at around 40 km that have been derived from this time series are higher than those calculated using other merged data sets. In this paper we will detail our efforts to understand why this is so. We will present analyses related to instrument drift, sampling biases and sensitivity to the method used to determine long term trends. Included along with the thorough analysis of the SAGE II - OSIRIS merged time series is an analysis of a SAGE II - MLS time series combined using the exact same method. Similarities and differences in the results derived from the two merged time series will also be discussed.

  10. Leaf morphology and photosynthetic adjustments among deciduous broad-leaved trees within the vertical canopy profile.

    PubMed

    Koike, T; Kitao, M; Maruyama, Y; Mori, S; Lei, T T

    2001-08-01

    Photosynthetic acclimation of deciduous broad-leaved tree species was studied along a vertical gradient within the canopy of a multi-species deciduous forest in northern Japan. We investigated variations in (1) local light regime and CO2 concentration ([CO2]), and (2) morphological (area, thickness and area per mass), biochemical (nitrogen and chlorophyll concentrations) and physiological (light-saturated photosynthetic rate) attributes of leaves of seven major species on three occasions (June, August and October). We studied early successional species, alder (Alnus hirsuta (Spach) Rupr.) and birch (Betula platyphylla var. japonica (Miq.) Hara); gap phase species, walnut (Juglans ailanthifolia Carrière) and ash (Fraxinus mandshurica var. japonica Rupr.); mid-successional species, basswood (Tilia japonica (Miq.) Simonk.) and elm (Ulmus davidiana var. japonica (Rehd.) Nakai); and the late-successional species, maple (Acer mono Bunge). All but maple initiated leaf unfolding from the lower part of the crown. The [CO2] within the vertical profile ranged from 320-350 ppm in the upper canopy to 405-560 ppm near the ground. The lowest and highest ambient [CO2] occurred during the day and during the night, respectively. This trend was observed consistently during the summer, but not when trees were leafless. Chlorophyll concentration was positively related to maximum photosynthetic rate within, but not among, species. Leaf senescence started from the inner part of the crown in alder and birch, but started either in the outer or top portion of the canopy of ash, basswood and maple. Chlorophyll (Chl) to nitrogen ratio in leaves increased with decreasing photon flux density. However, Chl b concentration in all species remained stable until the beginning of leaf senescence. Maximum photosynthetic rates observed in sun leaves of early successional species, gap phase or mid-successional species, and late successional species were 12.5-14.8 micromol m(-2) s(-1), 4.1-7.8 micromol

  11. Vertical profiling of aerosol hygroscopic properties in the planetary boundary layer during the PEGASOS campaigns

    NASA Astrophysics Data System (ADS)

    Rosati, Bernadette; Gysel, Martin; Rubach, Florian; Mentel, Thomas F.; Goger, Brigitta; Poulain, Laurent; Schlag, Patrick; Miettinen, Pasi; Pajunoja, Aki; Virtanen, Annele; Klein Baltink, Henk; Bas Henzing, J. S.; Größ, Johannes; Gobbi, Gian Paolo; Wiedensohler, Alfred; Kiendler-Scharr, Astrid; Decesari, Stefano; Facchini, Maria Cristina; Weingartner, Ernest; Baltensperger, Urs

    2016-06-01

    Vertical profiles of the aerosol particles hygroscopic properties, their mixing state as well as chemical composition were measured above northern Italy and the Netherlands. An aerosol mass spectrometer (AMS; for chemical composition) and a white-light humidified optical particle spectrometer (WHOPS; for hygroscopic growth) were deployed on a Zeppelin NT airship within the PEGASOS project. This allowed one to investigate the development of the different layers within the planetary boundary layer (PBL), providing a unique in situ data set for airborne aerosol particles properties in the first kilometre of the atmosphere. Profiles measured during the morning hours on 20 June 2012 in the Po Valley, Italy, showed an increased nitrate fraction at ˜ 100 m above ground level (a.g.l.) coupled with enhanced hygroscopic growth compared to ˜ 700 m a. g. l. This result was derived from both measurements of the aerosol composition and direct measurements of the hygroscopicity, yielding hygroscopicity parameters (κ) of 0.34 ± 0.12 and 0.19 ± 0.07 for 500 nm particles, at ˜ 100 and ˜ 700 m a. g. l., respectively. The difference is attributed to the structure of the PBL at this time of day which featured several independent sub-layers with different types of aerosols. Later in the day the vertical structures disappeared due to the mixing of the layers and similar aerosol particle properties were found at all probed altitudes (mean κ ≈ 0.18 ± 0.07). The aerosol properties observed at the lowest flight level (100 m a. g. l.) were consistent with parallel measurements at a ground site, both in the morning and afternoon. Overall, the aerosol particles were found to be externally mixed, with a prevailing hygroscopic fraction. The flights near Cabauw in the Netherlands in the fully mixed PBL did not feature altitude-dependent characteristics. Particles were also externally mixed and had an even larger hygroscopic fraction compared to the results in Italy. The mean κ from

  12. Constraining Early Cenozoic exhumation of the British Isles with vertical profile modelling

    NASA Astrophysics Data System (ADS)

    Doepke, Daniel; Cogné, Nathan; Chew, David

    2016-04-01

    Despite decades of research is the Early Cenozoic exhumation history of Ireland and Britain still poorly understood and subject to contentious debate (e.g., Davis et al., 2012 and subsequent comments). One reason for this debate is the difficultly of constraining the evolution of onshore parts of the British Isles in both time and space. The paucity of Mesozoic and Cenozoic onshore outcrops makes direct analysis of this time span difficult. Furthermore, Ireland and Britain are situated at a passive margin, where the amount of post-rift exhumation is generally very low. Classical thermochronological tools are therefore near the edge of their resolution and make precise dating of post-rift cooling events challenging. In this study we used the established apatite fission track and (U-Th-Sm)/He techniques, but took advantage of the vertical profile approach of Gallagher et al. (2005) implemented in the QTQt modelling package (Gallagher, 2012), to better constrain the thermal histories. This method allowed us to define the geographical extent of a Late Cretaceous - Early Tertiary cooling event and to show that it was centered around the Irish Sea. Thus, we argue that this cooling event is linked to the underplating of hot material below the crust centered on the Irish Sea (Jones et al., 2002; Al-Kindi et al., 2003), and demonstrate that such conclusion would have been harder, if not impossible, to draw by modelling the samples individually without the use of the vertical profile approach. References Al-Kindi, S., White, N., Sinha, M., England, R., and Tiley, R., 2003, Crustal trace of a hot convective sheet: Geology, v. 31, no. 3, p. 207-210. Davis, M.W., White, N.J., Priestley, K.F., Baptie, B.J., and Tilmann, F.J., 2012, Crustal structure of the British Isles and its epeirogenic consequences: Geophysical Journal International, v. 190, no. 2, p. 705-725. Jones, S.M., White, N., Clarke, B.J., Rowley, E., and Gallagher, K., 2002, Present and past influence of the Iceland

  13. Vertical AMS variation within basalt flow profiles from the Xitle volcano (Mexico) as indicator of heterogeneous strain in lava flows

    NASA Astrophysics Data System (ADS)

    Caballero-Miranda, C. I.; Alva-Valdivia, L. M.; González-Rangel, J. A.; Gogitchaishvili, A.; Urrutia-Fucugauchi, J.; Kontny, A.

    2016-02-01

    The within-flow vertical variation of anisotropy of the magnetic susceptibility (AMS) of three basaltic flow profiles from the Xitle volcano were investigated in relation to the lava flow-induced shear strain. Rock magnetic properties and opaque microscopy studies have shown that the magnetic mineralogy is dominated by Ti-poor magnetite with subtle vertical variations in grain size distribution: PSD grains dominate in a thin bottommost zone, and from base to top from PSD-MD to PSD-SD grains are found. The vertical variation of AMS principal direction patterns permitted identification of two to three main lava zones, some subdivided into subzones. The lower zone is very similar in all profiles with the magnetic foliation dipping toward the flow source, whereas the upper zone has magnetic foliation dipping toward the flow direction or alternates between dipping against and toward the flow direction. The K1 (maximum AMS axis) directions tend to be mostly parallel to the flow direction in both zones. The middle zone shows AMS axes diverging among profiles. We present heterogeneous strain ellipse distribution models for different flow velocities assuming similar viscosity to explain the AMS directions and related parameters of each zone. Irregular vertical foliations and transverse to flow lineation of a few samples at the bottommost and topmost part of profiles suggest SD inverse fabric, levels of intense friction, or degassing effects in AMS orientations.

  14. Moving Toward Continuous Satellite Monitoring of PM2.5 Using the GOES Aerosol/Smoke Product (GASP) and Aircraft Profiles

    NASA Astrophysics Data System (ADS)

    Stehr, J. W.; Kondragunta, S.; Anderson, D. C.; Arkinson, H.; Brent, L. C.; Goldberg, D.; He, H.; Liaskos, C.; Ring, A.; Dickerson, R. R.; Carpenter, S.; Ciren, P.; Xu, C.

    2012-12-01

    The NOAA Geostationary Operational Environmental Satellite (GOES) makes measurements of aerosol optical depth (AOD) every 30 minutes during daylight hours. Those measurements then feed the Automated Smoke Detection and Tracking algorithm that uses fire counts, trajectory modeling and pattern recognition to identify fire plumes, especially in the western U.S. Tying these satellite measurements to surface measurements of fine particles (PM2.5) would be a considerable benefit to the air quality community and to people who live in areas with elevated fine particle concentrations. Currently, these retrievals are useful in identifying areas of elevated PM2.5 concentrations and in forecasting PM2.5 by federal, state and local agencies, but are largely limited to qualitative measures of fine particle loading. Among other issues, layers of fine particles well above ground level, cloud contamination, and particle growth by addition of water in areas of high relative humidity are examples of barriers to a direct relationship between surface PM2.5 and satellite AOD. We have identified a path forward by using aircraft profiles to determine the vertical distribution of aerosol scattering in the atmosphere. In addition, long-term measurements of scattering and rapid measurements of PM2.5 at ground-based field sites have provided a relationship between scattering and mass. Simultaneous measurements of relative humidity and temperature allow one to calculate scattering the particles would have in a dry environment and relate that to fine particle mass measurements. A relationship between rapid scattering measurements and much slower PM2.5 mass measurements is then developed, which is used to tie rapid aircraft measurements of scattering to mass. In turn, aircraft profiles are then used to tie column measurements to those at the ground and to identify cases when satellite retrievals are likely to fail. The resulting algorithm should apply throughout much of the eastern U.S., so long

  15. Variability in Vertical Profiles of Water Vapor Associated with African Aerosol over the Tropical Atlantic

    NASA Astrophysics Data System (ADS)

    Huang, J.; Zhang, C.; Prospero, J. M.

    2007-12-01

    We used four years (2003-2006) of MODIS aerosol optical depth and concurrent AIRS profiled water vapor to explore how the vertical distribution of water vapor may systematically change with outbreaks of African aerosol over the tropical Atlantic Ocean. The first step was to look for a relationship in the Barbados region using in-situ Barbados dust record and the profiled relative humidity from meteorological soundings. We extended the study to the synoptic scale in the West Indies using the MODIS and AIRS products. In the tropical Atlantic, preliminary results indicate that water vapor at 850-1000 hPa is significantly less in July on dusty days than clean days over the northeastern tropical Atlantic [5-25N, 30-20W] where African dust is predominant. In contrast, over the southeastern tropical Atlantic [15S-0, 5W-10E], where African biomass burning smoke prevails, water vapor at 600-1000 hPa is significantly higher in August on smoky days than clean days. Additionally, in January when African mixed aerosol (dust and smoke) is anomalously high over the equatorial eastern tropical Atlantic [5S-5N, 15W-5E], less water vapor is observed at two levels: 925-1000 hPa and 500-600 hPa. It is hypothesized that these results are associated with the non-hygroscopic nature of African dust, the hygroscopic properties of African smoke, and their transport pathways over the tropical Atlantic. These results are useful in the design and diagnostics of model simulations of climate effects of aerosols such as aerosol related precipitation change.

  16. Smooth and Vertical Profile Dry Etching of Si Using XeF2 Plasma

    NASA Astrophysics Data System (ADS)

    Matsutani, Akihiro; Ohtsuki, Hideo; Koyama, Fumio

    2009-06-01

    We demonstrated the discharge of XeF2 plasma and investigated the dry etching process of Si using XeF2 plasma. A vertical etching profile and a smooth etched surface, which satisfy the requirements for optical device fabrication, were obtained. The etching rate of Si was 0.7 µm/min at 1 Pa and 100 W. It was found that the RF power dependences of the emission intensities of Xe, F, and XeF were similar to that of the etching rate of Si. The etching rate ratio of Si to SiO2 in the XeF2 plasma etching process was approximately 10, which was much larger than that in the CF4/O2 plasma etching process. We believe that XeF2 plasma etching is a very simple and useful process for Si-based optical devices such as photonic crystals, narrow optical waveguides, and micro-electro-mechanical systems (MEMS) device fabrication.

  17. Vertical Profiles of Aerosol Particle Sizes using MGS/TES and MRO/MCS

    NASA Astrophysics Data System (ADS)

    Wolff, M. J.; Clancy, R. T.; Smith, M. D.; Benson, J. L.; McConnochie, T. H.; Pankine, A.

    2012-12-01

    Vertical variations in aerosol particle sizes often have a dramatic impact on the state and evolution of the Martian atmosphere. Recent analyses of data from the Spectroscopy for the Investigation of the Characteristics of the Atmosphere of Mars (SPICAM), the Thermal Emission Spectrometer (TES), and the Mars Climate Sounder (MCS) instruments offer some long overdue progress in constraining this aspect of aerosols. However, significantly more work remains to be done along these lines in order to better constrain and inform modern dynamical simulations of the Martian atmosphere. Thus, the primary goal of our work is to perform retrievals of particle size as a function of altitude for both dust and water ice aerosols. The choice of the TES and MCS dataset, with pole-to-pole coverage over a period of nearly eight martian years, provides the crucial systematic temporal and spatial sampling. Our presentation will include: 1) A summary of our limb radiative transfer algorithms and retrieval schemes; 2) The initial results of the application of our particle size retrieval scheme to the 2001 TES and 2007 MCS observations of those planet encircling dust events; 3) Near-term plans for for additional retrievals (aphelion cloud season, lower optical depth locations and seasons, etc.); 4) Location of the archive to be used for the distribution of the derived profiles and associated retrieval metadata.

  18. Estimation of surface-level PM concentration from satellite observation taking into account the aerosol vertical profiles and hygroscopicity.

    PubMed

    Kim, Kwanchul; Lee, Kwon H; Kim, Ji I; Noh, Youngmin; Shin, Dong H; Shin, Sung K; Lee, Dasom; Kim, Jhoon; Kim, Young J; Song, Chul H

    2016-01-01

    Surface-level PM10 distribution was estimated from the satellite aerosol optical depth (AOD) products, taking the account of vertical profiles and hygroscopicity of aerosols over Jeju, Korea during March 2008 and October 2009. In this study, MODIS AOD data from the Terra and Aqua satellites were corrected with aerosol extinction profiles and relative humidity data. PBLH (Planetary Boundary Layer Height) was determined from MPLNET lidar-derived aerosol extinction coefficient profiles. Through statistical analysis, better agreement in correlation (R = 0.82) between the hourly PM10 concentration and hourly average Sunphotometer AOD was the obtained when vertical fraction method (VFM) considering Haze Layer Height (HLH) and hygroscopic growth factor f(RH) was used. The validity of the derived relationship between satellite AOD and surface PM10 concentration clearly demonstrates that satellite AOD data can be utilized for remote sensing of spatial distribution of regional PM10 concentration. PMID:26421659

  19. Estimation of surface-level PM concentration from satellite observation taking into account the aerosol vertical profiles and hygroscopicity.

    PubMed

    Kim, Kwanchul; Lee, Kwon H; Kim, Ji I; Noh, Youngmin; Shin, Dong H; Shin, Sung K; Lee, Dasom; Kim, Jhoon; Kim, Young J; Song, Chul H

    2016-01-01

    Surface-level PM10 distribution was estimated from the satellite aerosol optical depth (AOD) products, taking the account of vertical profiles and hygroscopicity of aerosols over Jeju, Korea during March 2008 and October 2009. In this study, MODIS AOD data from the Terra and Aqua satellites were corrected with aerosol extinction profiles and relative humidity data. PBLH (Planetary Boundary Layer Height) was determined from MPLNET lidar-derived aerosol extinction coefficient profiles. Through statistical analysis, better agreement in correlation (R = 0.82) between the hourly PM10 concentration and hourly average Sunphotometer AOD was the obtained when vertical fraction method (VFM) considering Haze Layer Height (HLH) and hygroscopic growth factor f(RH) was used. The validity of the derived relationship between satellite AOD and surface PM10 concentration clearly demonstrates that satellite AOD data can be utilized for remote sensing of spatial distribution of regional PM10 concentration.

  20. A Mathematical Model for Vertical Attitude Takeoff and Landing (VATOL) Aircraft Simulation. Volume 1; Model Description Application

    NASA Technical Reports Server (NTRS)

    Fortenbaugh, R. L.

    1980-01-01

    A mathematical model of a high performance airplane capable of vertical attitude takeoff and landing (VATOL) was developed. An off line digital simulation program incorporating this model was developed to provide trim conditions and dynamic check runs for the piloted simulation studies and support dynamic analyses of proposed VATOL configuration and flight control concepts. Development details for the various simulation component models and the application of the off line simulation program, Vertical Attitude Take-Off and Landing Simulation (VATLAS), to develop a baseline control system for the Vought SF-121 VATOL airplane concept are described.

  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 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

  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 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

  3. A sensitivity study on the retrieval of aerosol vertical profiles using the oxygen A-band

    NASA Astrophysics Data System (ADS)

    Colosimo, S. F.; Natraj, V.; Sander, S. P.; Stutz, J.

    2015-11-01

    Atmospheric absorption in the O2 A-band (12 950-13 200 cm-1) offers a unique opportunity to retrieve aerosol extinction profiles from space-borne measurements due to the large dynamic range of optical thickness in that spectral region. Absorptions in strong O2 lines are saturated; therefore, any radiance measured in these lines originates from scattering in the upper part of the atmosphere. Outside of O2 lines, or in weak lines, the atmospheric column absorption is small, and light penetrates to lower atmospheric layers, allowing for the quantification of aerosols and other scatterers near the surface. While the principle of aerosol profile retrieval using O2 A-band absorption from space is well known, a thorough quantification of the information content, i.e., the amount of vertical profile information that can be obtained, and the dependence of the information content on the spectral resolution of the measurements, has not been thoroughly conducted. Here, we use the linearized vector radiative transfer model VLIDORT to perform spectrally resolved simulations of atmospheric radiation in the O2 A-band in the presence of aerosol for four different generic scenarios: Urban, Highly polluted, Elevated layer, and Marine-Arctic. The high-resolution radiances emerging from the top of the atmosphere are degraded to different spectral resolutions, simulating spectrometers with different resolving powers. We use optimal estimation theory to quantify the information content in the aerosol profile retrieval with respect to different aerosol parameters and instrument spectral resolutions. The simulations show that better spectral resolution generally leads to an increase in the total amount of information that can be retrieved, with the number of degrees of freedom (DoF) varying between 0.34-2.11 at low resolution (5 cm-1) to 3.43-5.92 at high resolution (0.05 cm-1) for the four different cases. A particularly strong improvement was found in the retrieval of tropospheric

  4. The potential of LIRIC to validate the vertical profiles of the aerosol mass concentration estimated by an air quality model

    NASA Astrophysics Data System (ADS)

    Siomos, Nikolaos; Filoglou, Maria; Poupkou, Anastasia; Liora, Natalia; Dimopoulos, Spyros; Melas, Dimitris; Chaikovsky, Anatoli; Balis, Dimitris

    2015-04-01

    Vertical profiles of the aerosol mass concentration derived by a retrieval algorithm that uses combined sunphotometer and LIDAR data (LIRIC) were used in order to validate the mass concentration profiles estimated by the air quality model CAMx. LIDAR and CIMEL measurements of the Laboratory of Atmospheric Physics of the Aristotle University of Thessaloniki were used for this validation.The aerosol mass concentration profiles of the fine and coarse mode derived by CAMx were compared with the respective profiles derived by the retrieval algorithm. For the coarse mode particles, forecasts of the Saharan dust transportation model BSC-DREAM8bV2 were also taken into account. Each of the retrieval algorithm's profiles were matched to the models' profile with the best agreement within a time window of four hours before and after the central measurement. OPAC, a software than can provide optical properties of aerosol mixtures, was also employed in order to calculate the angstrom exponent and the lidar ratio values for 355nm and 532nm for each of the model's profiles aiming in a comparison with the angstrom exponent and the lidar ratio values derived by the retrieval algorithm for each measurement. The comparisons between the fine mode aerosol concentration profiles resulted in a good agreement between CAMx and the retrieval algorithm, with the vertical mean bias error never exceeding 7 μgr/m3. Concerning the aerosol coarse mode concentration profiles both CAMx and BSC-DREAM8bV2 values are severely underestimated, although, in cases of Saharan dust transportation events there is an agreement between the profiles of BSC-DREAM8bV2 model and the retrieval algorithm.

  5. Vertical profiling of aerosol hygroscopic properties in the planetary boundary layer during the PEGASOS campaigns

    NASA Astrophysics Data System (ADS)

    Rosati, B.; Gysel, M.; Rubach, F.; Mentel, T. F.; Goger, B.; Poulain, L.; Schlag, P.; Miettinen, P.; Pajunoja, A.; Virtanen, A.; Bialek, J.; Klein Baltink, H.; Henzing, J. S.; Größ, J.; Gobbi, G. P.; Wiedensohler, A.; Kiendler-Scharr, A.; O'Dowd, C.; Decesari, S.; Facchini, M. C.; Weingartner, E.; Baltensperger, U.

    2015-03-01

    Airborne measurements of the aerosol hygroscopic and optical properties as well as chemical composition were performed in the Netherlands and northern Italy on board of a Zeppelin NT airship during the PEGASOS field campaigns in 2012. The vertical changes in aerosol properties during the development of the mixing layer were studied. Hygroscopic growth factors (GF) at 95% relative humidity were determined using the white-light humidified optical particles spectrometer (WHOPS) for dry diameters of 300 and 500 nm particles. These measurements were supplemented by an aerosol mass spectrometer (AMS) and an aethalometer providing information on the aerosol chemical composition. Several vertical profiles between 100 and 700 m a.g. were flown just after sunrise close to the San Pietro Capofiume ground station in the Po Valley, Italy. During the early morning hours the lowest layer (newly developing mixing layer) contained a high nitrate fraction (20%) which was coupled with enhanced hygroscopic growth. In the layer above (residual layer) small nitrate fractions of ~ 2% were measured as well as low GFs. After full mixing of the layers, typically around noon and with increased temperature, the nitrate fraction decreased to 2% at all altitudes and led to similar hygroscopicity values as found in the residual layer. These distinct vertical and temporal changes underline the importance of airborne campaigns to study aerosol properties during the development of the mixed layer. The aerosol was externally mixed with 22 and 67% of the 500 nm particles in the range GF < 1.1 and GF > 1.5, respectively. Contributors to the non-hygroscopic mode in the observed size range are most likely mineral dust and biological material. Mean hygroscopicity parameters (κ) were 0.34, 0.19 and 0.18 for particles in the newly forming mixing layer, residual layer and fully mixed layer, respectively. These results agree well with those from chemical analysis which found values of κ = 0.27, 0.21 and 0

  6. Influence of the vertical absorption profile of mixed Asian dust plumes on aerosol direct radiative forcing over East Asia

    NASA Astrophysics Data System (ADS)

    Noh, Young Min; Lee, Kwonho; Kim, Kwanchul; Shin, Sung-Kyun; Müller, Detlef; Shin, Dong Ho

    2016-08-01

    We estimate the aerosol direct radiative forcing (ADRF) and heating rate profiles of mixed East Asian dust plumes in the solar wavelength region ranging from 0.25 to 4.0 μm using the Santa Barbara Discrete Ordinate Atmospheric Radiative Transfer (SBDART) code. Vertical profiles of aerosol extinction coefficients and single-scattering albedos (SSA) were derived from measurements with a multi-wavelength Raman lidar system. The data are used as input parameters for our radiative transfer calculations. We considered four cases of radiative forcing in SBDART: 1. dust, 2. pollution, 3. mixed dust plume and the use of vertical profiles of SSA, and 4. mixed dust plumes and the use of column-averaged values of SSA. In our sensitivity study we examined the influence of SSA and aerosol layer height on our results. The ADRF at the surface and in the atmosphere shows a small dependence on the specific shape of the aerosol extinction vertical profile and its light-absorption property for all four cases. In contrast, at the top of the atmosphere (TOA), the ADRF is largely affected by the vertical distribution of the aerosols extinction. This effect increases if the light-absorption capacity (decrease of SSA) of the aerosols increases. We find different radiative effects in situations in which two layers of aerosols had different light-absorption properties. The largest difference was observed at the TOA for an absorbing aerosol layer at high altitude in which we considered in one case the vertical profile of SSA and in another case the column-averaged SSA only. The ADRF at the TOA increases when the light-absorbing aerosol layer is located above 3 km altitude. The differences between height-resolved SSA, which can be obtained from lidar data, and total layer-mean SSA indicates that the use of a layer-mean SSA can be rather misleading as it can induce a large error in the calculation of the ADRF at the TOA, which in turn may cause errors in the vertical profiles of heating rates.

  7. Comparing the cloud vertical structure derived from several methods based on radiosonde profiles and ground-based remote sensing measurements

    NASA Astrophysics Data System (ADS)

    Costa-Surós, M.; Calbó, J.; González, J. A.; Long, C. N.

    2014-08-01

    The cloud vertical distribution and especially the cloud base height, which is linked to cloud type, are important characteristics in order to describe the impact of clouds on climate. In this work, several methods for estimating the cloud vertical structure (CVS) based on atmospheric sounding profiles are compared, considering the number and position of cloud layers, with a ground-based system that is taken as a reference: the Active Remote Sensing of Clouds (ARSCL). All methods establish some conditions on the relative humidity, and differ in the use of other variables, the thresholds applied, or the vertical resolution of the profile. In this study, these methods are applied to 193 radiosonde profiles acquired at the Atmospheric Radiation Measurement (ARM) Southern Great Plains site during all seasons of the year 2009 and endorsed by Geostationary Operational Environmental Satellite (GOES) images, to confirm that the cloudiness conditions are homogeneous enough across their trajectory. The perfect agreement (i.e., when the whole CVS is estimated correctly) for the methods ranges between 26 and 64%; the methods show additional approximate agreement (i.e., when at least one cloud layer is assessed correctly) from 15 to 41%. Further tests and improvements are applied to one of these methods. In addition, we attempt to make this method suitable for low-resolution vertical profiles, like those from the outputs of reanalysis methods or from the World Meteorological Organization's (WMO) Global Telecommunication System. The perfect agreement, even when using low-resolution profiles, can be improved by up to 67% (plus 25% of the approximate agreement) if the thresholds for a moist layer to become a cloud layer are modified to minimize false negatives with the current data set, thus improving overall agreement.

  8. Application of a new vertical profiling tool (ESASS) for sampling groundwater quality during hollow-stem auger drilling

    USGS Publications Warehouse

    Harte, P.T.; Flanagan, S.M.

    2011-01-01

    A new tool called ESASS (Enhanced Screen Auger Sampling System) was developed by the U.S. Geological Survey. The use of ESASS, because of its unique U.S. patent design (U.S. patent no. 7,631,705 B1), allows for the collection of representative, depth-specific groundwater samples (vertical profiling) in a quick and efficient manner using a 0.305-m long screen auger during hollow-stem auger drilling. With ESASS, the water column in the flights above the screen auger is separated from the water in the screen auger by a specially designed removable plug and collar. The tool fits inside an auger of standard inner diameter (82.55 mm). The novel design of the system constituted by the plug, collar, and A-rod allows the plug to be retrieved using conventional drilling A-rods. After retrieval, standard-diameter (50.8 mm) observation wells can be installed within the hollow-stem augers. Testing of ESASS was conducted at one waste-disposal site with tetrachloroethylene (PCE) contamination and at two reference sites with no known waste-disposal history. All three sites have similar geology and are underlain by glacial, stratified-drift deposits. For the applications tested, ESASS proved to be a useful tool in vertical profiling of groundwater quality. At the waste site, PCE concentrations measured with ESASS profiling at several depths were comparable (relative percent difference <25%) to PCE concentrations sampled from wells. Vertical profiling with ESASS at the reference sites illustrated the vertical resolution achievable in the profile system; shallow groundwater quality varied by a factor of five in concentration of some constituents (nitrate and nitrite) over short (0.61 m) distances. Ground Water Monitoring & Remediation ?? 2011, National Ground Water Association. No claim to original US government works.

  9. Application of a new vertical profiling tool (ESASS) for sampling groundwater quality during hollow-stem auger drilling

    USGS Publications Warehouse

    Harte, Philip T.; Flanagan, Sarah M.

    2011-01-01

    A new tool called ESASS (Enhanced Screen Auger Sampling System) was developed by the U.S. Geological Survey. The use of ESASS, because of its unique U.S. patent design (U.S. patent no. 7,631,705 B1), allows for the collection of representative, depth-specific groundwater samples (vertical profiling) in a quick and efficient manner using a 0.305-m long screen auger during hollow-stem auger drilling. With ESASS, the water column in the flights above the screen auger is separated from the water in the screen auger by a specially designed removable plug and collar. The tool fits inside an auger of standard inner diameter (82.55 mm). The novel design of the system constituted by the plug, collar, and A-rod allows the plug to be retrieved using conventional drilling A-rods. After retrieval, standard-diameter (50.8 mm) observation wells can be installed within the hollow-stem augers. Testing of ESASS was conducted at one waste-disposal site with tetrachloroethylene (PCE) contamination and at two reference sites with no known waste-disposal history. All three sites have similar geology and are underlain by glacial, stratified-drift deposits. For the applications tested, ESASS proved to be a useful tool in vertical profiling of groundwater quality. At the waste site, PCE concentrations measured with ESASS profiling at several depths were comparable (relative percent difference <25%) to PCE concentrations sampled from wells. Vertical profiling with ESASS at the reference sites illustrated the vertical resolution achievable in the profile system; shallow groundwater quality varied by a factor of five in concentration of some constituents (nitrate and nitrite) over short (0.61 m) distances.

  10. Vertical profile and components of marine planktonic archaea in the Pacific sector of the Arctic Oceean

    NASA Astrophysics Data System (ADS)

    Akiyama, S.; Amano (Sato), C.; Uchida, M.; Utsumi, M.

    2011-12-01

    Ocean was carried out during a cruise, with R/V Mirai from September to October 2008 (MR08-04). We focused on 3 stations located in Mendeleyev Ridge, Northwind Ridge and Canada Basin. CARD-FISH and clone library techniques targeted on archaeal specific 16S rRNA gene were used to investigate vertical profile of marine planktonic archaeal abundance and characterize their community structure. The results showed that their community structure comprised Group I Crenarchaeota, Group II, III and IV Euryarchaeota. Group I Crenarchaeota outnumbered Group II Euryarchaeota through the water column (0.0064-2.5 x 104 and 0.0038-1.3 x 104 cells/mL, respectively). Although their abundance decreased exponentially with depth, Group I Crenarchaeota relative abundance of the toltal bacteria were high in > 200 m depth at all station. Besides, Group III Euryarchaeota sequences were more frequently detected than other oceans (24 of 115 sequences; 20.9%). It could be said that Group III Euryarchaeota is more predominant in this ocean. Moreover, it was observed that vertical profile of their abundance and components were different depending on the stations and depth.

  11. Vertical Profiles of Light-Absorbing Aerosol: A Combination of In-situ and AERONET Observations during NASA DISCOVER-AQ

    NASA Astrophysics Data System (ADS)

    Ziemba, L. D.; Beyersdorf, A. J.; Chen, G.; Corr, C.; Crumeyrolle, S.; Giles, D. M.; Holben, B. N.; Hudgins, C.; Martin, R.; Moore, R.; Shook, M.; Thornhill, K. L., II; Winstead, E.; Anderson, B. E.

    2014-12-01

    Understanding the vertical profile of atmospheric aerosols plays a vital role in utilizing spaceborne, column-integrated satellite observations. The properties and distribution of light-absorbing aerosol are particularly uncertain despite significant air quality and climate ramifications. Advanced retrieval algorithms are able to derive complex aerosol properties (e.g., wavelength-dependent absorption coefficient and single scattering albedo) from remote-sensing measurements, but quantitative relationships to surface conditions remain a challenge. Highly systematic atmospheric profiling during four unique deployments for the NASA DISCOVER-AQ project (Baltimore, MD, 2011; San Joaquin Valley, CA, 2013; Houston, TX, 2013; Denver, CO, 2014) allow statistical assessment of spatial, temporal, and source-related variability for light-absorbing aerosol properties in these distinct regions. In-situ sampling in conjunction with a dense network of AERONET sensors also allows evaluation of the sensitivity, limitations, and advantages of remote-sensing data products over a wide range of conditions. In-situ aerosol and gas-phase observations were made during DISCOVER-AQ aboard the NASA P-3B aircraft. Aerosol absorption coefficients were measured by a Particle Soot Absorption Photometer (PSAP). Approximately 200 profiles for each of the four deployments were obtained, from the surface (25-300m altitude) to 5 km, and are used to calculate absorption aerosol optical depths (AAODs). These are quantitatively compared to AAOD derived from AERONET Level 1.5 retrievals to 1) explore discrepancies between measurements, 2) quantify the fraction of AAOD that exists directly at the surface and is often missed by airborne sampling, and 3) evaluate the potential for deriving ground-level black carbon (BC) concentrations for air quality prediction. Aerosol size distributions are used to assess absorption contributions from mineral dust, both at the surface and aloft. SP2 (Single Particle Soot

  12. Vertical Profiles of Light Scattering, Light Absorption, and Single Scattering Albedo during the Dry, Biomass Burning Season in Southern Africa and Comparisons of In Situ and Remote Sensing Measurements of Aerosol Optical Depths

    NASA Technical Reports Server (NTRS)

    Magi, Brian I.; Hobbs, Peter V.; Schmid, Beat; Redermann, Jens

    2003-01-01

    Airborne in situ measurements of vertical profiles of aerosol light scattering, light absorption, and single scattering albedo (omega (sub 0)) are presented for a number of locations in southern Africa during the dry, biomass burning season. Features of the profiles include haze layers, clean air slots, and marked decreases in light scattering in passing from the boundary layer into the free troposphere. Frequency distributions of omega (sub 0) reflect the strong influence of smoke from biomass burning. For example, during a period when heavy smoke was advected into the region from the north, the mean value of omega (sub 0) in the boundary layer was 0.81 +/- 0.02 compared to 0.89 +/- 0.03 prior to this intrusion. Comparisons of layer aerosol optical depths derived from the in situ measurements with those measured by a Sun photometer aboard the aircraft show excellent agreement.

  13. Heat Budget Calculation in the Convective Boundary Layer on a 4 × 4 Vertical versus Time Grid from Aircraft and Surface Measurements.

    NASA Astrophysics Data System (ADS)

    Lukas, John C.

    2000-09-01

    Aircraft, portable tower, and radiosonde measurements from 4 August 1989 (day 68) of the First International Satellite Land Surface Climatology Project (ISLCP) Field Experiment (FIFE), over fairly flat terrain in Kansas, are used for the reconstruction of the heat conservation equation. The calculation grid consists of three grouped flight levels and the surface, and three 1-h blocks, within the midday convective boundary layer (CBL). The day chosen had a week warm front disturbance in addition to the usual summertime southern flow over the midwestern United States. Significant vertical and temporal structure, which should not be bulk averaged, was observed for all terms. The upper layer showed warming sustained at a constant rate around noon and appeared decoupled from the surface and the middle levels in the later hours. Excess warming was due to advection and possibly entrainment. Consequently, the heat flux divergence also had a nonzero vertical gradient. Advection proves to be an important term and does not average out when driven by a synoptic feature. Its east-west component improved the balance of the heat equation at all levels. Partial flight intertrack and total CBL volume standard deviations for terms and residuals are carried through explicitly.

  14. EFFECTS OF NITROGEN PHOTOABSORPTION CROSS SECTION RESOLUTION ON MINOR SPECIES VERTICAL PROFILES IN TITAN’S UPPER ATMOSPHERE

    SciTech Connect

    Luspay-Kuti, A.; Mandt, K. E.; Greathouse, T. K.; Plessis, S.

    2015-03-01

    The significant variations in both measured and modeled densities of minor species in Titan’s atmosphere call for the evaluation of possible influencing factors in photochemical modeling. The effect of nitrogen photoabsorption cross section selection on the modeled vertical profiles of minor species is analyzed here, with particular focus on C{sub 2}H{sub 6} and HCN. Our results show a clear impact of cross sections used on all neutral and ion species studied. Affected species include neutrals and ions that are not primary photochemical products, including species that do not even contain nitrogen. The results indicate that photochemical models that employ low-resolution cross sections may significantly miscalculate the vertical profiles of minor species. Such differences are expected to have important implications for Titan’s overall atmospheric structure and chemistry.

  15. Local fluctuations of ozone from 16 km to 45 km deduced from in situ vertical ozone profile

    NASA Technical Reports Server (NTRS)

    Moreau, G.; Robert, C.

    1994-01-01

    A vertical ozone profile obtained by an in situ ozone sonde from 16 km to 45 km, has allowed to observe local ozone concentration variations. These variations can be observed, thanks to a fast measurement system based on a UV absorption KrF excimer laser beam in a multipass cell. Ozone standard deviation versus altitude calculated from the mean is derived. Ozone variations or fluctuations are correlated with the different dynamic zones of the stratosphere.

  16. A sensitivity study on the retrieval of aerosol vertical profiles using the oxygen A-band

    NASA Astrophysics Data System (ADS)

    Fedele Colosimo, Santo; Natraj, Vijay; Sander, Stanley P.; Stutz, Jochen

    2016-04-01

    Atmospheric absorption in the O2 A-band (12 950-13 200 cm-1) offers a unique opportunity to retrieve aerosol extinction profiles from space-borne measurements due to the large dynamic range of optical thickness in that spectral region. Absorptions in strong O2 lines are saturated; therefore, any radiance measured in these lines originates from scattering in the upper part of the atmosphere. Outside of O2 lines, or in weak lines, the atmospheric column absorption is small, and light penetrates to lower atmospheric layers, allowing for the quantification of aerosols and other scatterers near the surface.

    While the principle of aerosol profile retrieval using O2 A-band absorption from space is well-known, a thorough quantification of the information content, i.e., the amount of vertical profile information that can be obtained, and the dependence of the information content on the spectral resolution of the measurements, has not been thoroughly conducted. Here, we use the linearized vector radiative transfer model VLIDORT to perform spectrally resolved simulations of atmospheric radiation in the O2 A-band for four different aerosol extinction profile scenarios: urban (urban-rural areas), highly polluted (megacity areas with large aerosol extinction), elevated layer (identifying elevated plumes, for example for biomass burning) and low extinction (representative of small aerosol extinction, such as vegetated, marine and arctic areas). The high-resolution radiances emerging from the top of the atmosphere measurements are degraded to different spectral resolutions, simulating spectrometers with different resolving powers. We use optimal estimation theory to quantify the information content in the aerosol profile retrieval with respect to different aerosol parameters and instrument spectral resolutions. The simulations show that better spectral resolution generally leads to an increase in the total amount of information that can be retrieved, with the number of

  17. Vertical profiles of ozone, VOCs and meteorological parameters in within and outside of Mexico City during the MILAGRO field Campaign

    NASA Astrophysics Data System (ADS)

    Marquez, C.; Greenberg, J.; Bueno, E.; Bernabe, R.; Aguilar, J.; Blanco, S.; Wöhrnschimmel, H.; Guenther, A.; Cardenas, B.; Turnipseed, A.

    2007-05-01

    High ozone levels with maxima over 250 ppb have been an air quality problem in Mexico City for more than a decade. This ozone is produced in the daytime by photochemical reactions, initiated by its precursors, nitrogen oxides (NOx) and volatile organic compounds (VOCs) in the presence of solar ultraviolet radiation. The objective of this work is to contribute to the understanding of the evolution of these air pollutants at different heights of the boundary layer by means of vertical profile measurements. Ozone, VOCs and meteorological vertical profiles were determined in Northern Mexico City (T0 site) using a tethered balloon for 10 days during the MILAGRO field Campaign 2006, between 4 AM and 4 PM. Measurements were done up to 1000 meter above ground (ozone and meteorological parameters) and up to 200 m above ground for VOCs. VOCs samples were collected during 4 minutes in canisters and analyzed with GC-FID to identify 13 species (ethane, propane, propylene, butane, acetylene, pentane, hexane, heptane, benzene, octane, toluene, nonane and o-xylene). For 4 of the days, VOC integrated samples were also taken using personal pumps and absorbent cartridges at height between 200 and 1000 m. Sample cartridges were analyzed by GC-MS for volatile organic compounds (n-butane, i-pentane, n- pentane, benzene, toluene, ethyl-benzene, o-xylene, m&p-xylene, 1,2,4-tri-methyl-benzene and C3-benzenes). Ozone vertical profiles, frequently presented high concentrations above 400 m in the early morning. During the daytime, more homogeneous profiles indicate an increased vertical mixing. VOCs profiles show similar concentrations for all heights at dawn. In the morning, highest concentrations were determined at a height of about 100 meter, whereas at noon and in the afternoon concentrations decreased with height. Comparing VOC concentrations during the course of a day, highest values are measured in the morning. The highest VOC concentrations were propane, butane, and toluene. For some

  18. Relation of Cloud Occurrence Frequency, Overlap, and Effective Thickness Derived from CALIPSO and CloudSat Merged Cloud Vertical Profiles

    NASA Technical Reports Server (NTRS)

    Kato, Seiji; Sun-Mack, Sunny; Miller, Walter F.; Rose, Fred G.; Chen, Yan; Minnis, Patrick; Wielicki, Bruce A.

    2009-01-01

    A cloud frequency of occurrence matrix is generated using merged cloud vertical profile derived from Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) and Cloud Profiling Radar (CPR). The matrix contains vertical profiles of cloud occurrence frequency as a function of the uppermost cloud top. It is shown that the cloud fraction and uppermost cloud top vertical pro les can be related by a set of equations when the correlation distance of cloud occurrence, which is interpreted as an effective cloud thickness, is introduced. The underlying assumption in establishing the above relation is that cloud overlap approaches the random overlap with increasing distance separating cloud layers and that the probability of deviating from the random overlap decreases exponentially with distance. One month of CALIPSO and CloudSat data support these assumptions. However, the correlation distance sometimes becomes large, which might be an indication of precipitation. The cloud correlation distance is equivalent to the de-correlation distance introduced by Hogan and Illingworth [2000] when cloud fractions of both layers in a two-cloud layer system are the same.

  19. Retrieval of carbon dioxide vertical profiles from solar occultation observations and associated error budgets for ACE-FTS and CASS-FTS

    NASA Astrophysics Data System (ADS)

    Sioris, C. E.; Boone, C. D.; Nassar, R.; Sutton, K. J.; Gordon, I. E.; Walker, K. A.; Bernath, P. F.

    2014-07-01

    An algorithm is developed to retrieve the vertical profile of carbon dioxide in the 5 to 25 km altitude range using mid-infrared solar occultation spectra from the main instrument of the ACE (Atmospheric Chemistry Experiment) mission, namely the Fourier transform spectrometer (FTS). The main challenge is to find an atmospheric phenomenon which can be used for accurate tangent height determination in the lower atmosphere, where the tangent heights (THs) calculated from geometric and timing information are not of sufficient accuracy. Error budgets for the retrieval of CO2 from ACE-FTS and the FTS on a potential follow-on mission named CASS (Chemical and Aerosol Sounding Satellite) are calculated and contrasted. Retrieved THs have typical biases of 60 m relative to those retrieved using the ACE version 3.x software after revisiting the temperature dependence of the N2 CIA (collision-induced absorption) laboratory measurements and accounting for sulfate aerosol extinction. After correcting for the known residual high bias of ACE version 3.x THs expected from CO2 spectroscopic/isotopic inconsistencies, the remaining bias for tangent heights determined with the N2 CIA is -20 m. CO2 in the 5-13 km range in the 2009-2011 time frame is validated against aircraft measurements from CARIBIC (Civil Aircraft for the Regular Investigation of the atmosphere Based on an Instrument Container), CONTRAIL (Comprehensive Observation Network for Trace gases by Airline), and HIPPO (HIAPER Pole-to-Pole Observations), yielding typical biases of -1.7 ppm in the 5-13 km range. The standard error of these biases in this vertical range is 0.4 ppm. The multi-year ACE-FTS data set is valuable in determining the seasonal variation of the latitudinal gradient which arises from the strong seasonal cycle in the Northern Hemisphere troposphere. The annual growth of CO2 in this time frame is determined to be 2.6 ± 0.4 ppm year-1, in agreement with the currently accepted global growth rate based on

  20. Comparison of improved Aura Tropospheric Emission Spectrometer (TES) CO{sub 2} with HIPPO and SGP aircraft profile measurements

    SciTech Connect

    Kulawik, S. S.; Worden, J. R.; Wofsy, S. C.; Biraud, S. C.; Nassar, R.; Jones, D. B.A.; Olsen, E. T.; Osterman, G. B.

    2012-02-01

    Comparisons are made between mid-tropospheric Tropospheric Emission Spectrometer (TES) carbon dioxide (CO{sub 2}) satellite measurements and ocean profiles from three Hiaper Pole-to-Pole Observations (HIPPO) campaigns and land aircraft profiles from the United States Southern Great Plains (SGP) Atmospheric Radiation Measurement (ARM) site over a 4-yr period. These comparisons are used to characterize the bias in the TES CO{sub 2} estimates and to assess whether calculated and actual uncertainties and sensitivities are consistent. The HIPPO dataset is one of the few datasets spanning the altitude range where TES CO{sub 2} estimates are sensitive, which is especially important for characterization of biases. We find that TES CO{sub 2} estimates capture the seasonal and latitudinal gradients observed by HIPPO CO{sub 2} measurements; actual errors range from 0.8–1.2 ppm, depending on the campaign, and are approximately 1.4 times larger than the predicted errors. The bias of TES versus HIPPO is within 0.85 ppm for each of the 3 campaigns; however several of the sub-tropical TES CO{sub 2} estimates are lower than expected based on the calculated errors. Comparisons of aircraft flask profiles, which are measured from the surface to 5 km, to TES CO{sub 2} at the SGP ARM site show good agreement with an overall bias of 0.1 ppm and rms of 1.0 ppm. We also find that the predicted sensitivity of the TES CO{sub 2} estimates is too high, which results from using a multi-step retrieval for CO{sub 2} and temperature. We find that the averaging kernel in the TES product corrected by a pressure-dependent factor accurately reflects the sensitivity of the TES CO{sub 2} product.

  1. Noise generated by a flight weight, air flow control valve in a vertical takeoff and landing aircraft thrust vectoring system

    NASA Technical Reports Server (NTRS)

    Huff, Ronald G.

    1989-01-01

    Tests were conducted in the NASA Lewis Research Center's Powered Lift Facility to experimentally evaluate the noise generated by a flight weight, 12 in. butterfly valve installed in a proposed vertical takeoff and landing thrust vectoring system. Fluctuating pressure measurements were made in the circular duct upstream and downstream of the valve. This data report presents the results of these tests. The maximum overall sound pressure level is generated in the duct downstream of the valve and reached a value of 180 dB at a valve pressure ratio of 2.8. At the higher valve pressure ratios the spectra downstream of the valve is broad banded with its maximum at 1000 Hz.

  2. Retrieval of Vertical LAI Profiles Over Tropical Rain Forests using Waveform Lidar at La Selva, Costa Rica

    NASA Technical Reports Server (NTRS)

    Tang, Hao; Dubayah, Ralph; Swatantra, Anu; Hofton, Michelle; Sheldon, Sage; Clark, David B.; Blair, Bryan

    2012-01-01

    This study explores the potential of waveform lidar in mapping the vertical and spatial distributions of leaf area index (LAI) over the tropical rain forest of La Selva Biological Station in Costa Rica. Vertical profiles of LAI were derived at 0.3 m height intervals from the Laser Vegetation Imaging Sensor (LVIS) data using the Geometric Optical and Radiative Transfer (GORT) model. Cumulative LAI profiles obtained from LVIS were validated with data from 55 ground to canopy vertical transects using a modular field tower to destructively sample all vegetation. Our results showed moderate agreement between lidar and field derived LAI (r2=0.42, RMSE=1.91, bias=-0.32), which further improved when differences between lidar and tower footprint scales (r2=0.50, RMSE=1.79, bias=0.27) and distance of field tower from lidar footprint center (r2=0.63, RMSE=1.36, bias=0.0) were accounted for. Next, we mapped the spatial distribution of total LAI across the landscape and analyzed LAI variations over different land cover types. Mean values of total LAI were 1.74, 5.20, 5.41 and 5.62 over open pasture, secondary forests, regeneration forests after selective-logging and old-growth forests respectively. Lastly, we evaluated the sensitivities of our LAI retrieval model to variations in canopy/ground reflectance ratio and to waveform noise such as induced by topographic slopes. We found for both, that the effects were not significant for moderate LAI values (about 4). However model derivations of LAI might be inaccurate in areas of high-slope and high LAI (about 8) if ground return energies are low. This research suggests that large footprint waveform lidar can provide accurate vertical LAI profile estimates that do not saturate even at the high LAI levels in tropical rain forests and may be a useful tool for understanding the light transmittance within these canopies.

  3. Modified power law equations for vertical wind profiles. [in investigation of windpower plant siting

    NASA Technical Reports Server (NTRS)

    Spera, D. A.; Richards, T. R.

    1979-01-01

    In an investigation of windpower plant siting, equations are presented and evaluated for a wind profile model which incorporates both roughness and wind speed effects, while retaining the basic simplicity of the Hellman power law. These equations recognize the statistical nature of wind profiles and are compatible with existing analytical models and recent wind profile data. Predictions of energy output based on the proposed profile equations are 10% to 20% higher than those made with the 1/7 power law. In addition, correlation between calculated and observed blade loads is significantly better at higher wind speeds when the proposed wind profile model is used than when a constant power model is used.

  4. Characteristics of tropospheric ozone variability over an urban site in Southeast Asia: A study based on MOZAIC and MOZART vertical profiles

    NASA Astrophysics Data System (ADS)

    Sahu, L. K.; Sheel, Varun; Kajino, M.; Gunthe, Sachin S.; Thouret, ValéRie; Nedelec, P.; Smit, Herman G.

    2013-08-01

    Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC) profiles of O3 and CO were analyzed to study their variation in the troposphere over Bangkok. Mixing ratios of O3 and CO were enhanced in planetary boundary layer (PBL) being highest in winter followed by summer and wet seasons. The daytime profiles of O3 show higher values compared to nighttime observations in PBL region, but little differences were observed in the free troposphere. The decreasing mixing ratios of O3 in the lower and upper troposphere were associated with shallow and deep convections, respectively. Back trajectory and fire count data indicate that the seasonal variations in trace gases were caused mainly by the regional shift in long-range transport and biomass-burning patterns. In wet season, flow of oceanic air and negligible presence of local biomass burning resulted in lowest O3 and CO, while their high levels in dry season were due to extensive biomass burning and transport of continental air masses. The Model for Ozone and Related Chemical Tracers (MOZART) underestimated both O3 and CO in the PBL region but overestimated these in the free troposphere. Simulations of O3 and CO also show the daytime/nighttime differences but do not capture several key features observed in the vertical distributions. The observed and simulated values of O3 and CO during September-November 2006 were significantly higher than the same period of 2005. The year-to-year differences were mainly due to El Niño-led extensive fires in Indonesia during 2006 but normal condition during 2005.

  5. Global distribution of vertical wavenumber spectra in the lower stratosphere observed using high-vertical-resolution temperature profiles from COSMIC GPS radio occultation

    NASA Astrophysics Data System (ADS)

    Noersomadi; Tsuda, T.

    2016-02-01

    We retrieved temperature (T) profiles with a high vertical resolution using the full spectrum inversion (FSI) method from the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) GPS radio occultation (GPS-RO) data from January 2007 to December 2009. We studied the characteristics of temperature perturbations in the stratosphere at 20-27 km altitude. This height range does not include a sharp jump in the background Brunt-Väisälä frequency squared (N2) near the tropopause, and it was reasonably stable regardless of season and latitude. We analyzed the vertical wavenumber spectra of gravity waves (GWs) with vertical wavelengths ranging from 0.5 to 3.5 km, and we integrated the (total) potential energy EpT. Another integration of the spectra from 0.5 to 1.75 km was defined as EpS for short vertical wavelength GWs, which was not studied with the conventional geometrical optics (GO) retrievals. We also estimated the logarithmic spectral slope (p) for the saturated portion of spectra with a linear regression fitting from 0.5 to 1.75 km.Latitude and time variations in the spectral parameters were investigated in two longitudinal regions: (a) 90-150° E, where the topography was more complicated, and (b) 170-230° E, which is dominated by oceans. We compared EpT, EpS, and p, with the mean zonal winds (U) and outgoing longwave radiation (OLR). We also show a ratio of EpS to EpT and discuss the generation source of EpS. EpT and p clearly showed an annual cycle, with their maximum values in winter at 30-50° N in region (a), and 50-70° N in region (b), which was related to the topography. At 30-50° N in region (b), EpT and p exhibited some irregular variations in addition to an annual cycle. In the Southern Hemisphere, we also found an annual oscillation in EpT and p, but it showed a time lag of about 2 months relative to U. Characteristics of EpTand p in the tropical region seem to be related to convective activity. The ratio of EpT to the

  6. Retrieval assessment using the microwave simulation tool for the High Altitude and LOng range aircraft HALO: humidity, temperature and hydrometeor profiles

    NASA Astrophysics Data System (ADS)

    Mech, M.; Crewell, S.; Orlandi, E.; Hirsch, L.

    2011-12-01

    New cloud observation techniques are needed to improve our understanding of the impact of clouds on the Earth's water cycle and radiation budget, which still represents one of the largest uncertainties in global and regional climate modelling. An airborne platform for such observation techniques will be provided by the new German research aircraft HALO (High Altitude LOng Range). In early 2013 a dedicated remote sensing mission NARVAL employing the microwave package HAMP (HALO Microwave Package; 36 channels microwave radiometer and 35.5 GHz Doppler radar), wind and water vapour lidar as well as auxiliary measurements will invest cloud systems in the North Atlantic in much higher detail than feasible on space-borne platforms. An advanced set of microwave remote cloud sensing instruments is to be operated on board of HALO. It consists of a cloud radar and a suite of passive radiometers in different frequency bands. The radar MIRA-36 operates at 35.5 GHz. The frequencies for the passive microwave radiometers were selected in allusion to the AMSU-A and -B sounder. In addition to the channels along the 60 GHz oxygen complex measurements along the 118 GHz oxygen line hint at the vertical distribution of liquid water that show a strong emission increase with frequency. This combination can be used for precipitation retrieval. In addition to include channels in the water vapor lines at 22.235 GHz and 183.31 GHz, information about the water vapor distribution throughout the troposphere can be retrieved. By including higher microwave channels sensitive to scattering in the ice phase various precipitation retrieval algorithms can be compared with measurements from HAMP. Retrieval algorithms and potential flight patterns are investigated using a simulation test bed combining cloud model and radiative transfer simulations. Thereby the cloud resolving model simulations and the forward radiative transfer calculations include a one- and two-moment cloud microphysical scheme with

  7. Stratospheric NO2 vertical profile retrieved from ground-based Zenith-Sky DOAS observations at Kiruna, Sweden

    NASA Astrophysics Data System (ADS)

    Gu, Myojeong; Enell, Carl-Fredrik; Hendrick, François; Pukite, Janis; Van Roozendael, Michel; Platt, Ulrich; Raffalski, Uwe; Wagner, Thomas

    2014-05-01

    Stratospheric NO2 destroys ozone and acts as a buffer against halogen-catalyzed ozone loss through the formation of reservoir species (ClONO2, BrONO2). Since the importance of both mechanisms depends on the altitude, the investigation of stratospheric NO2 vertical distribution can provide more insight into the role of nitrogen compounds in the destruction of ozone. Here we present stratospheric NO2 vertical profiles retrieved from twilight ground-based zenith-sky DOAS observations at Kiruna, Sweden (68.84°N, 20.41°E) covering 1997 - 2013 periods. This instrument observes zenith scattered sunlight. The sensitivity for stratospheric trace gases is highest during twilight due to the maximum altitude of the scattering profile and the light path through the stratosphere, which vary with the solar zenith angle. The profiling algorithm, based on the Optimal Estimation Method, has been developed by IASB-BIRA and successfully applied at other stations (Hendrick et al., 2004). The basic principle behind this profiling approach is that during twilight, the mean Rayleigh scattering altitude scans the stratosphere rapidly, providing height-resolved information on the absorption by stratospheric NO2. In this study, the long-term evolution of the stratospheric NO2 profile at polar latitude will be investigated. Hendrick, F., B. Barret, M. Van Roozendael, H. Boesch, A. Butz, M. De Mazière, F. Goutail, C. Hermans, J.-C. Lambert, K. Pfeilsticker, and J.-P. Pommereau, Retrieval of nitrogen dioxide stratospheric profiles from ground-based zenith-sky UV-visible observations: Validation of the technique through correlative comparisons, Atmospheric Chemistry and Physics, 4, 2091-2106, 2004

  8. Estimation of raindrop drop size distribution vertical profile from simultaneous micro rain radar and 2D video disdrometer measurements

    NASA Astrophysics Data System (ADS)

    Adirosi, Elisa; Baldini, Luca; Roberto, Nicoletta; Montopoli, Mario; Gorgucci, Eugenio; Gatlin, Patrick; Tokay, Ali

    2016-04-01

    Experimental field campaigns of rain precipitation usually require the coexistence of several ground and satellite based observations in order to guarantee a more complete analysis of the collected case studies at the various spatial and temporal scales of interest. In the framework of the Ground Validation programme of the NASAA/JAXA Global Precipitation Measurement (GPM) mission, several climate regions of the Earth have been interested by various field campaigns involving experimental setup which include one or more ground based disdrometers and profilers. In such situation a typical implementation of the measurement scheme consists of a pair of K-band vertically pointing micro rain radar (MRR) and a 2D video disdrometer (2DVD) installed close each other. Since 2DVD estimates are referred to the ground level, the co-located MRR is supposed to provide complementary vertical profiles of drop size distribution (DSD) measurements. However, if not properly processed MRR and 2DVD raw data can lead to erroneous interpretations of the underlying microphysics. In this work, we investigate some typical issues occurring when dealing with MRR and 2DVD observations proposing techniques to ensure the adequate data quality required in typical field validation campaigns. More in detail, MRR is an affordable continuous wave frequency-modulated radar (CWFM) typically used at vertical incidence. In the MMR configuration used, DSD profiles are estimated from Doppler spectra determined by drops falling at different velocities and at different heights from 1000 meters almost up to the ground level with a vertical resolution of 35 meters and time resolution up to 10 seconds. The importance of the microphysical measurements from MRR are related to the effects of the vertical gradients of rain precipitation at the sub-resolution scale of the measurements based remote sensing instruments such as those provided by the dual frequency radar of GPM as well as by ground based weather radars

  9. High resolution profiles of vertical particulate organic matter export off Cape Blanc, Mauritania: Degradation processes and ballasting effects

    NASA Astrophysics Data System (ADS)

    Iversen, Morten Hvitfeldt; Nowald, Nicolas; Ploug, Helle; Jackson, George A.; Fischer, Gerhard

    2010-06-01

    Vertical carbon fluxes between the surface and 2500 m depth were estimated from in situ profiles of particle size distributions and abundances me/asured off Cape Blanc (Mauritania) related to deep ocean sediment traps. Vertical mass fluxes off Cape Blanc were significantly higher than recent global estimates in the open ocean. The aggregates off Cape Blanc contained high amounts of ballast material due to the presence of coccoliths and fine-grained dust from the Sahara desert, leading to a dominance of small and fast-settling aggregates. The largest changes in vertical fluxes were observed in the surface waters (<250 m), and, thus, showing this site to be the most important zone for aggregate formation and degradation. The degradation length scale ( L), i.e. the fractional degradation of aggregates per meter settled, was estimated from vertical fluxes derived from the particle size distribution through the water column. This was compared with fractional remineralization rate of aggregates per meter settled derived from direct ship-board measurements of sinking velocity and small-scale O 2 fluxes to aggregates measured by micro-sensors. Microbial respiration by attached bacteria alone could not explain the degradation of organic matter in the upper ocean. Instead, flux feeding from zooplankton organisms was indicated as the dominant degradation process of aggregated carbon in the surface ocean. Below the surface ocean, microbes became more important for the degradation as zooplankton was rare at these depths.

  10. Autonomous system for vertical profiling of the marine environment at a moored station

    NASA Astrophysics Data System (ADS)

    Ostrovskii, A. G.; Zatsepin, A. G.; Soloviev, V. A.; Tsibulsky, A. L.; Shvoev, D. A.

    2013-03-01

    This paper presents new results of the research and development project on the moored profiler Aqualog aimed at multidisciplinary studies and ecological monitoring of the marine environment. The data on the profiler's operation are summarized based upon the field experiments in the northeastern Black Sea in 2011. An important scientific result obtained by using the profiler during the experiments was the discovery of the countercurrent below the Black Sea Rim Current in the layer between the 500 m and 900 m depth.

  11. Effects of a nonuniform vertical profile of chlorophyll concentration on remote-sensing reflectance of the ocean.

    PubMed

    Stramska, Malgorzata; Stramski, Dariusz

    2005-03-20

    Numerical simulations of radiative transfer were used to examine the effects of a nonuniform vertical profile of the inherent optical properties of the water column associated with the vertical profile of chlorophyll concentration, Chl(z), on the spectral remote-sensing reflectance, Rrs(gamma), of the ocean. Using the Gaussian function that describes the Chl(z) profile, we simulated a relatively broad range of open-ocean conditions characterized by the presence of a subsurface Chl maximum at depths greater than or equal to 20 m. The simulations for a vertically nonuniform Chl(z) were compared with reference simulations for a homogeneous ocean whose Chl was identical to the surface Chl of inhomogeneous cases. The range of values for the Gaussian parameters that produce significant differences in Rrs(gamma) (> 5%) was determined. For some vertical structures of Chl(z) considered, the magnitude of Rrs(gamma) and the blue-to-green band ratios of Rrs(gamma) differ significantly from the reference values of homogeneous ocean (> 70% in extreme cases of low surface chlorophyll of 0.02 mg m(-3) and shallow pigment maximum at 20 m). The differences are small or negligible when the nonuniform profiles are characterized by a surface Chl greater than 0.4 mg m(-3) or a depth of Chl maximum greater than 45 m (65 m in extremely clear waters with a surface Chl of 0.02 mg m(-3) or less). The comparison of modeling results with the current algorithm for retrieving the global distribution of chlorophyll from satellite imagery of ocean color suggests that strong effects of the subsurface chlorophyll maximum on reflectance at low surface chlorophyll concentrations can lead to a severalfold overestimation in the algorithm-derived surface chlorophyll. Examples of field data from the Sea of Japan and the north polar Atlantic Ocean are used to illustrate various nonuniform pigment profiles and their effect on the blue-to-green ratio of Rrs(gamma).

  12. The influence of local circulations on vertical profiles of NO2 and O3 at semi-rural sites during DISCOVER-AQ campaigns in California, Texas, and Colorado

    NASA Astrophysics Data System (ADS)

    Stein Zweers, D. C.; Pickering, K. E.; Clark, R. D.; Weinheimer, A. J.; Flynn, C.; Mazzuca, G.; Spinei, E.

    2014-12-01

    Through use of the Millersville University tethersonde balloon an NO2-sonde, developed at the Royal Netherlands Meteorological Institute (KNMI), profiled the lower boundary layer as part of the larger NASA Earth Venture program funded mission. This campaign known as DISCOVER-AQ stands for 'Deriving Information on Surface Conditions from Column and Vertically Resolved Observations Relevant to Air Quality'. Recent results from the California, Texas, and Colorado deployments of DISCOVER-AQ highlight the importance of semi-continuous, daytime measurement of the vertical distribution of ozone and NO2 in the lower boundary layer. The balloon profiles, typically from the surface to 500m above ground level, fill an important gap between surface measurements and the lowest extent of aircraft measurements. This near-surface region of the atmosphere is highly variable and local circulation features including land-sea breezes and mountain-valley breezes were observed. These circulations altered local transport patterns and led to changes in the chemical regime at each site. These processes were especially apparent at Smith Point, Texas during an extreme pollution event on 25 September 2013. The extent to which these local circulations influenced diurnal variation and vertical distribution of NO2 and ozone is evaluated and compared for each semi-rural site using wind direction and other meteorological data. NO2-sonde profile data is compared to ground station trace gas analyzers and where available, column and profile measurements from PANDORA spectrometer instruments. These data measured in the segment of the near-surface atmosphere most critical for human health are unique and crucial for validation of satellite columns and atmospheric chemical models.

  13. Simulation and flight studies of an approach profile indicator for VTOL aircraft

    NASA Technical Reports Server (NTRS)

    Moen, G. C.; Yenni, K. R.

    1975-01-01

    Simulation and flight investigations were conducted by using a method of providing supplementary information to the pilot in conjunction with a closed-circuit-television display during a VTOL instrument final approach including deceleration and hover. The supplementary information included range, cross range, ground speed, altitude, and rate-of-climb error and was displayed on an instrument called an approach profile indicator. The display was arranged to provide both quasi-command and situation information. Pilot comments indicated that the approach-profile-indicator display concept in conjunction with the closed-circuit television resulted in a decreased pilot workload and an increase in pilot confidence. Also, the results indicated that the approach profile repeatability was significantly improved because of the ground-speed and altitude information provided on the approach profile indicator.

  14. A model for the vertical sound speed and absorption profiles in Titan's atmosphere based on Cassini-Huygens data.

    PubMed

    Petculescu, Andi; Achi, Peter

    2012-05-01

    Measurements of thermodynamic quantities in Titan's atmosphere during the descent of Huygens in 2005 are used to predict the vertical profiles for the speed and intrinsic attenuation (or absorption) of sound. The calculations are done using one author's previous model modified to accommodate non-ideal equations of state. The vertical temperature profile places the tropopause about 40 km above the surface. In the model, a binary nitrogen-methane composition is assumed for Titan's atmosphere, quantified by the methane fraction measured by the gas chromatograph/mass spectrometer (GCMS) onboard Huygens. To more accurately constrain the acoustic wave number, the variation of thermophysical properties (specific heats, viscosity, and thermal conductivity) with altitude is included via data extracted from the NIST Chemistry WebBook [URL webbook.nist.gov, National Institute of Standards and Technology Chemistry WebBook (Last accessed 10/20/2011)]. The predicted speed of sound profile fits well inside the spread of the data recorded by Huygens' active acoustic sensor. In the N(2)-dominated atmosphere, the sound waves have negligible relaxational dispersion and mostly classical (thermo-viscous) absorption. The cold and dense environment of Titan can sustain acoustic waves over large distances with relatively small transmission losses, as evidenced by the small absorption. A ray-tracing program is used to assess the bounds imposed by the zonal wind-measured by the Doppler Wind Experiment on Huygens-on long-range propagation.

  15. High-Latitude Topside Ionospheric Vertical Electron-Density-Profile Changes in Response to Large Magnetic Storms

    NASA Technical Reports Server (NTRS)

    Benson, Robert F.; Fainberg, Joseph; Osherovich, Vladimir A.; Truhlik, Vladimir; Wang, Yongli; Bilitza, Dieter; Fung, Shing F.

    2015-01-01

    Large magnetic-storm induced changes have been detected in high-latitude topside vertical electron-density profiles Ne(h). The investigation was based on the large database of topside Ne(h) profiles and digital topside ionograms from the International Satellites for Ionospheric Studies (ISIS) program available from the NASA Space Physics Data Facility (SPDF) at http://spdf.gsfc.nasa.gov/isis/isis-status.html. This large database enabled Ne(h) profiles to be obtained when an ISIS satellite passed through nearly the same region of space before, during, and after a major magnetic storm. A major goal was to relate the magnetic-storm induced high-latitude Ne(h) profile changes to solar-wind parameters. Thus an additional data constraint was to consider only storms where solar-wind data were available from the NASA/SPDF OMNIWeb database. Ten large magnetic storms (with Dst less than -100 nT) were identified that satisfied both the Ne(h) profile and the solar-wind data constraints. During five of these storms topside ionospheric Ne(h) profiles were available in the high-latitude northern hemisphere and during the other five storms similar ionospheric data were available in the southern hemisphere. Large Ne(h) changes were observed during each one of these storms. Our concentration in this paper is on the northern hemisphere. The data coverage was best for the northern-hemisphere winter. Here Ne(h) profile enhancements were always observed when the magnetic local time (MLT) was between 00 and 03 and Ne(h) profile depletions were always observed between 08 and 10 MLT. The observed Ne(h) deviations were compared with solar-wind parameters, with appropriate time shifts, for four storms.

  16. Sea Ice Topography Profiling using Laser Altimetry from Small Unmanned Aircraft Systems

    NASA Astrophysics Data System (ADS)

    Crocker, Roger Ian

    Arctic sea ice is undergoing a dramatic transition from a perennial ice pack with a high prevalence of old multiyear ice, to a predominantly seasonal ice pack comprised primarily of young first-year and second-year ice. This transition has brought about changes in the sea ice thickness and topography characteristics, which will further affect the evolution and survivability of the ice pack. The varying ice conditions have substantial implications for commercial operations, international affairs, regional and global climate, our ability to model climate dynamics, and the livelihood of Arctic inhabitants. A number of satellite and airborne missions are dedicated to monitoring sea ice, but they are limited by their spatial and temporal resolution and coverage. Given the fast rate of sea ice change and its pervasive implications, enhanced observational capabilities are needed to augment the current strategies. The CU Laser Profilometer and Imaging System (CULPIS) is designed specifically for collecting fine-resolution elevation data and imagery from small unmanned aircraft systems (UAS), and has a great potential to compliment ongoing missions. This altimeter system has been integrated into four different UAS, and has been deployed during Arctic and Antarctic science campaigns. The CULPIS elevation measurement accuracy is shown to be 95±25 cm, and is limited primarily by GPS positioning error (<25 cm), aircraft attitude determination error (<20 cm), and sensor misalignment error (<20 cm). The relative error is considerably smaller over short flight distances, and the measurement precision is shown to be <10 cm over a distance of 200 m. Given its fine precision, the CULPIS is well suited for measuring sea ice topography, and observed ridge height and ridge separation distributions are found to agree with theoretical distributions to within 5%. Simulations demonstrate the inability of course-resolution measurements to accurately represent the theoretical distributions

  17. Vertical profiles of black carbon measured by a micro-aethalometer in summer in the North China Plain

    NASA Astrophysics Data System (ADS)

    Ran, Liang; Deng, Zhaoze; Xu, Xiaobin; Yan, Peng; Lin, Weili; Wang, Ying; Tian, Ping; Wang, Pucai; Pan, Weilin; Lu, Daren

    2016-08-01

    Black carbon (BC) is a dominant absorber in the visible spectrum and a potent factor in climatic effects. Vertical profiles of BC were measured using a micro-aethalometer attached to a tethered balloon during the Vertical Observations of trace Gases and Aerosols (VOGA) field campaign, in summer 2014 at a semirural site in the North China Plain (NCP). The diurnal cycle of BC vertical distributions following the evolution of the mixing layer (ML) was investigated for the first time in the NCP region. Statistical parameters including identified mixing height (Hm) and average BC mass concentrations within the ML (Cm) and in the free troposphere (Cf) were obtained for a selected dataset of 67 vertical profiles. Hm was usually lower than 0.2 km in the early morning and rapidly rose thereafter due to strengthened turbulence. The maximum height of the ML was reached in the late afternoon. The top of a full developed ML exceeded 1 km on sunny days in summer, while it stayed much lower on cloudy days. The sunset triggered the collapse of the ML, and a stable nocturnal boundary layer (NBL) gradually formed. Accordingly, the highest level Cm was found in the early morning and the lowest was found in the afternoon. In the daytime, BC was almost uniformly distributed within the ML and significantly decreased above the ML. During the field campaign, Cm averaged about 5.16 ± 2.49 µg m-3, with a range of 1.12 to 14.49 µg m-3, comparable with observational results in many polluted urban areas such as Milan in Italy and Shanghai in China. As evening approached, BC gradually built up near the surface and exponentially declined with height. In contrast to the large variability found both in Hm and Cm, Cf stayed relatively unaffected through the day. Cf was less than 10 % of the ground level under clean conditions, while it amounted to half of the ground level in some polluted cases. In situ measurements of BC vertical profiles would hopefully have an important implication for

  18. Estimating Oceanic Primary Production Using Vertical Irradiance and Chlorophyll Profiles from Ocean Gliders in the North Atlantic.

    PubMed

    Hemsley, Victoria S; Smyth, Timothy J; Martin, Adrian P; Frajka-Williams, Eleanor; Thompson, Andrew F; Damerell, Gillian; Painter, Stuart C

    2015-10-01

    An autonomous underwater vehicle (Seaglider) has been used to estimate marine primary production (PP) using a combination of irradiance and fluorescence vertical profiles. This method provides estimates for depth-resolved and temporally evolving PP on fine spatial scales in the absence of ship-based calibrations. We describe techniques to correct for known issues associated with long autonomous deployments such as sensor calibration drift and fluorescence quenching. Comparisons were made between the Seaglider, stable isotope ((13)C), and satellite estimates of PP. The Seaglider-based PP estimates were comparable to both satellite estimates and stable isotope measurements.

  19. Vertical profiles of CO and CH4 in the lower and middle troposphere over the Eastern United States January 1978

    NASA Technical Reports Server (NTRS)

    Reichle, H. G., Jr.; Condon, E. P.

    1979-01-01

    Samples of tropospheric air were obtained over the Eastern United States during January of 1978. These samples were analyzed by gas chromatography using flame ionization detection to produce vertical profiles of carbon monoxide and methane from the surface to 8 km. The carbon monoxide mixing ratios at 35 deg N and 45 deg N agree with previously published values; however, the mixing ratio at 25 deg N was significantly lower than most published values. The methane mixing ratio was weakly dependent on latitude and has an average value of 1.64 ppm.

  20. Estimating Oceanic Primary Production Using Vertical Irradiance and Chlorophyll Profiles from Ocean Gliders in the North Atlantic.

    PubMed

    Hemsley, Victoria S; Smyth, Timothy J; Martin, Adrian P; Frajka-Williams, Eleanor; Thompson, Andrew F; Damerell, Gillian; Painter, Stuart C

    2015-10-01

    An autonomous underwater vehicle (Seaglider) has been used to estimate marine primary production (PP) using a combination of irradiance and fluorescence vertical profiles. This method provides estimates for depth-resolved and temporally evolving PP on fine spatial scales in the absence of ship-based calibrations. We describe techniques to correct for known issues associated with long autonomous deployments such as sensor calibration drift and fluorescence quenching. Comparisons were made between the Seaglider, stable isotope ((13)C), and satellite estimates of PP. The Seaglider-based PP estimates were comparable to both satellite estimates and stable isotope measurements. PMID:26301371

  1. Balloon measurements of the vertical ionization profile over southern Israel and comparison to mid-latitude observations

    NASA Astrophysics Data System (ADS)

    Yaniv, Roy; Yair, Yoav; Price, Colin; Nicoll, Keri; Harrison, Giles; Artamonov, Anton; Usoskin, Ilya

    2016-11-01

    Airborne measurements using meteorological balloons were conducted for the first time from southern Israel (geographic 30°35'N, 34°45'E geomagnetic 27°6'N 112°23'E) for measuring the vertical ionization profile during solar cycle 24. The results show the differences (increase of ~30%) in count rates as we proceed from solar maximum toward solar minimum. The observed altitude of maximum ionization (the Regener-Pfotzer maximum) was between 17-20 km, and it agrees well with results from other simultaneous measurements conducted at different latitudes (Reading, UK and Zaragoza-Barcelona, Spain). When compared with predictions of an analytical model, we find a highly significant correlation (R2=0.97) between our observations and the computed ionization profiles. The difference in count rates can be attributed to the height of the tropopause due to the model using a US standard atmosphere that differs from the measured atmospheric parameters above Israel.

  2. Temporal variability of the trade wind inversion: Measured with a boundary layer vertical profiler. Master's thesis

    SciTech Connect

    Grindinger, C.M.

    1992-05-01

    This study uses Hawaiian Rainband Project (HaRP) data, from the summer of 1991, to show a boundary layer wind profiler can be used to measure the trade wind inversion. An algorithm has been developed for the profiler that objectively measures the depth of the moist oceanic boundary layer. The Hilo inversion, measured by radiosonde, is highly correlated with the moist oceanic boundary layer measured by the profiler at Paradise Park. The inversion height on windward Hawaii is typically 2253 + or - 514 m. The inversion height varies not only on a daily basis, but on less than an hourly basis. It has a diurnal, as well as a three to four day cycle. There appears to be no consistent relationship between inversion height and precipitation. Currently, this profiler is capable of making high frequency (12 minute) measurements of the inversion base variation, as well as other features.

  3. Cooperative suction by vertical capillary array pump for controlling flow profiles of microfluidic sensor chips.

    PubMed

    Horiuchi, Tsutomu; Hayashi, Katsuyoshi; Seyama, Michiko; Inoue, Suzuyo; Tamechika, Emi

    2012-10-18

    A passive pump consisting of integrated vertical capillaries has been developed for a microfluidic chip as an useful component with an excellent flow volume and flow rate. A fluidic chip built into a passive pump was used by connecting the bottoms of all the capillaries to a top surface consisting of a thin layer channel in the microfluidic chip where the thin layer channel depth was smaller than the capillary radius. As a result the vertical capillaries drew fluid cooperatively rather than independently, thus exerting the maximum suction efficiency at every instance. This meant that a flow rate was realized that exhibited little variation and without any external power or operation. A microfluidic chip built into this passive pump had the ability to achieve a quasi-steady rather than a rapidly decreasing flow rate, which is a universal flow characteristic in an ordinary capillary.

  4. The vertical extent of the log-linear wind profile under stable stratification

    NASA Astrophysics Data System (ADS)

    Skibin, D.; Businger, J. A.

    The nondimensional wind shear is examined over a wide range of stable and highly stable stratifications. The velocity profiles from the Kansas, Moses Lake and Wangara experiments are analyzed using Webb's (1970) method. The results show that the log-linear function accurately represents the velocity profile close to the ground, up to z/L ≈ 1. The log-linear layer covers a significant part of the lower nocturnal boundary layer and extends above the constant flux layer.

  5. Oxygen profile and clogging in vertical flow sand filters for on-site wastewater treatment.

    PubMed

    Petitjean, A; Forquet, N; Boutin, C

    2016-04-01

    13 million people (about 20% of the population) use on-site wastewater treatment in France. Buried vertical sand filters are often built, especially when the soil permeability is not sufficient for septic tank effluent infiltration in undisturbed soil. Clogging is one of the main problems deteriorating the operation of vertical flow filters for wastewater treatment. The extent of clogging is not easily assessed, especially in buried vertical flow sand filters. We suggest examining two possible ways of detecting early clogging: (1) NH4-N/NO3-N outlet concentration ratio, and (2) oxygen measurement within the porous media. Two pilot-scale filters were equipped with probes for oxygen concentration measurements and samples were taken at different depths for pollutant characterization. Influent and effluent grab-samples were taken three times a week. The systems were operated using batch-feeding of septic tank effluent. Qualitative description of oxygen transfer processes under unclogged and clogged conditions is presented. NH4-N outlet concentration appears to be useless for early clogging detection. However, NO3-N outlet concentration and oxygen content allows us to diagnose the early clogging of the system.

  6. Oxygen profile and clogging in vertical flow sand filters for on-site wastewater treatment.

    PubMed

    Petitjean, A; Forquet, N; Boutin, C

    2016-04-01

    13 million people (about 20% of the population) use on-site wastewater treatment in France. Buried vertical sand filters are often built, especially when the soil permeability is not sufficient for septic tank effluent infiltration in undisturbed soil. Clogging is one of the main problems deteriorating the operation of vertical flow filters for wastewater treatment. The extent of clogging is not easily assessed, especially in buried vertical flow sand filters. We suggest examining two possible ways of detecting early clogging: (1) NH4-N/NO3-N outlet concentration ratio, and (2) oxygen measurement within the porous media. Two pilot-scale filters were equipped with probes for oxygen concentration measurements and samples were taken at different depths for pollutant characterization. Influent and effluent grab-samples were taken three times a week. The systems were operated using batch-feeding of septic tank effluent. Qualitative description of oxygen transfer processes under unclogged and clogged conditions is presented. NH4-N outlet concentration appears to be useless for early clogging detection. However, NO3-N outlet concentration and oxygen content allows us to diagnose the early clogging of the system. PMID:26775157

  7. Electric Field Profiles over Hurricanes, Tropical Cyclones, and Thunderstorms with an Instrumented ER-2 Aircraft

    NASA Technical Reports Server (NTRS)

    Mach, Doug M.; Blakeslee, Richard J.; Bateman, Monte G.; Bailey, Jeff C.

    2007-01-01

    Over the past several years, we have flown a set of calibrated electric field meters (FMs) on the NASA high altitude ER-2 aircraft over oceanic and landbased storms in a number of locations. These included tropical oceanic cyclones and hurricanes in the Caribbean and Atlantic ocean during the Third and Fourth Convection And Moisture EXperiment (CAMEX-3,1998; CAMEX-4, 2001), thunderstorms in Florida during the TExas FLorida UNderflight (TEFLUN, 1998) experiment, tropical thunderstorms in Brazil during the Tropical Rainfall Measuring Mission - Large Scale Biosphere-Atmosphere Experiment in Amazonia (TRMM LBA, 1999), and finally, hurricanes and tropical cyclones in the Caribbean and Western Pacific and thunderstorms in Central America during the Tropical Cloud Systems and Processes (TCSP, 2005) mission. Between these various missions we have well over 50 sorties that provide a unique insights on the different electrical environment, evolution and activity occurring in and around these various types of storms. In general, the electric fields over the tropical oceanic storms and hurricanes were less than a few kilovolts per meter at the ER-2 altitude, while the lightning rates were low. Land-based thunderstorms often produced high lightning activity and correspondingly higher electric fields.

  8. How Informative are the Vertical Buoyancy and the Prone Gliding Tests to Assess Young Swimmers’ Hydrostatic and Hydrodynamic Profiles?

    PubMed Central

    Barbosa, Tiago M.; Costa, Mário J.; Morais, Jorge E; Moreira, Marc; Silva, António J.; Marinho, Daniel A.

    2012-01-01

    The aim of this research was to develop a path-flow analysis model to highlight the relationships between buoyancy and prone gliding tests and some selected anthropometrical and biomechanical variables. Thirty-eight young male swimmers (12.97 ± 1.05 years old) with several competitive levels were evaluated. It were assessed the body mass, height, fat mass, body surface area, vertical buoyancy, prone gliding after wall push-off, stroke length, stroke frequency and velocity after a maximal 25 [m] swim. The confirmatory model included the body mass, height, fat mass, prone gliding test, stroke length, stroke frequency and velocity. All theoretical paths were verified except for the vertical buoyancy test that did not present any relationship with anthropometrical and biomechanical variables nor with the prone gliding test. The good-of-fit from the confirmatory path-flow model, assessed with the standardized root mean square residuals (SRMR), is considered as being close to the cut-off value, but even so not suitable of the theory (SRMR = 0.11). As a conclusion, vertical buoyancy and prone gliding tests are not the best techniques to assess the swimmer’s hydrostatic and hydrodynamic profile, respectively. PMID:23486528

  9. How Informative are the Vertical Buoyancy and the Prone Gliding Tests to Assess Young Swimmers' Hydrostatic and Hydrodynamic Profiles?

    PubMed

    Barbosa, Tiago M; Costa, Mário J; Morais, Jorge E; Moreira, Marc; Silva, António J; Marinho, Daniel A

    2012-05-01

    The aim of this research was to develop a path-flow analysis model to highlight the relationships between buoyancy and prone gliding tests and some selected anthropometrical and biomechanical variables. Thirty-eight young male swimmers (12.97 ± 1.05 years old) with several competitive levels were evaluated. It were assessed the body mass, height, fat mass, body surface area, vertical buoyancy, prone gliding after wall push-off, stroke length, stroke frequency and velocity after a maximal 25 [m] swim. The confirmatory model included the body mass, height, fat mass, prone gliding test, stroke length, stroke frequency and velocity. All theoretical paths were verified except for the vertical buoyancy test that did not present any relationship with anthropometrical and biomechanical variables nor with the prone gliding test. The good-of-fit from the confirmatory path-flow model, assessed with the standardized root mean square residuals (SRMR), is considered as being close to the cut-off value, but even so not suitable of the theory (SRMR = 0.11). As a conclusion, vertical buoyancy and prone gliding tests are not the best techniques to assess the swimmer's hydrostatic and hydrodynamic profile, respectively. PMID:23486528

  10. Estimating regional methane emissions from agriculture using aircraft measurements of concentration profiles

    NASA Astrophysics Data System (ADS)

    Wratt, D. S.; Gimson, N. R.; Brailsford, G. W.; Lassey, K. R.; Bromley, A. M.; Bell, M. J.

    This paper describes a "top-down" approach for estimating regional surface fluxes of methane, and its application to a pastoral farming region in New Zealand. The approach is based on air sampling from aircraft and interpretation by mesoscale dispersion modelling. The goal is an independent cross-check for an agricultural region of "bottom-up" emission estimation methods like those used for inventory reporting under the United Nations Framework Convention on Climate Change (UNFCCC). The "top-down" strategy infers emissions over an agricultural region from differences between methane concentrations measured upwind and downwind of the region. The approach was trialed over the Manawatu agricultural region of New Zealand's North Island. As expected, measured concentration differences were largest at low wind speeds (2-3 m s -1 ). However, during these low wind conditions the concentration differences could not be reliably inverted to provide emission estimates, because of the complex variability in air flow caused by topography and land-sea temperature contrasts. Useful emission estimates were obtained during days with higher wind speed (about 8 m s -1), as the strong synoptic-scale flow then suppressed the development of complex local flows. The upwind-downwind concentration differences were smaller during these conditions of stronger flow, so that precision limits to concentration measurements became significant. Methane fluxes (in the range of 20-100 mg m -2 d -1) calculated under the stronger wind speed conditions were consistent with "bottom-up" estimates scaled from per-animal emission factors, enhancing confidence in the inventory-reporting methodology.

  11. Retrieved Vertical Profiles of Latent Heat Release Using TRMM Rainfall Products

    NASA Technical Reports Server (NTRS)

    Tao, W.-K.; Lang, S.; Olson, W. S.; Meneghini, R.; Yang, S.; Simpson, J.; Kummerow, C.; Smith, E.

    2000-01-01

    This paper represents the first attempt to use TRMM rainfall information to estimate the four dimensional latent heating structure over the global tropics for February 1998. The mean latent heating profiles over six oceanic regions (TOGA COARE IFA, Central Pacific, S. Pacific Convergence Zone, East Pacific, Indian Ocean and Atlantic Ocean) and three continental regions (S. America, Central Africa and Australia) are estimated and studied. The heating profiles obtained from the results of diagnostic budget studies over a broad range of geographic locations are used to provide comparisons and indirect validation for the heating algorithm estimated heating profiles. Three different latent heating algorithms, the Goddard Convective-Stratiform (CSH) heating, the Goddard Profiling (GPROF) heating, and the Hydrometeor heating (HH) are used and their results are intercompared. The horizontal distribution or patterns of latent heat release from the three different heating retrieval methods are quite similar. They all can identify the areas of major convective activity (i.e., a well defined ITCZ in the Pacific, a distinct SPCZ) in the global tropics. The magnitude of their estimated latent heating release is also not in bad agreement with each other and with those determined from diagnostic budget studies. However, the major difference among these three heating retrieval algorithms is the altitude of the maximum heating level. The CSH algorithm estimated heating profiles only show one maximum heating level, and the level varies between convective activity from various geographic locations. These features are in good agreement with diagnostic budget studies. By contrast, two maximum heating levels were found using the GPROF heating and HH algorithms. The latent heating profiles estimated from all three methods can not show cooling between active convective events. We also examined the impact of different TMI (Multi-channel Passive Microwave Sensor) and PR (Precipitation Radar

  12. Model predictions of wind and turbulence profiles associated with an ensemble of aircraft accidents

    NASA Technical Reports Server (NTRS)

    Williamson, G. G.; Lewellen, W. S.; Teske, M. E.

    1977-01-01

    The feasibility of predicting conditions under which wind/turbulence environments hazardous to aviation operations exist is studied by examining a number of different accidents in detail. A model of turbulent flow in the atmospheric boundary layer is used to reconstruct wind and turbulence profiles which may have existed at low altitudes at the time of the accidents. The predictions are consistent with available flight recorder data, but neither the input boundary conditions nor the flight recorder observations are sufficiently precise for these studies to be interpreted as verification tests of the model predictions.

  13. Validation of MODIS liquid water path for oceanic nonraining warm clouds: Implications on the vertical profile of cloud water content

    NASA Astrophysics Data System (ADS)

    Zhou, Lingli; Liu, Qi; Liu, Dongyang; Xie, Lei; Qi, Lin; Liu, Xiantong

    2016-05-01

    Liquid water path (LWP) derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) is validated using the Advanced Microwave Scanning Radiometer-EOS (AMSR-E) retrievals for global oceanic nonraining warm clouds, with focus on the vertically homogeneous (VH) model and adiabatically stratified (AS) model of liquid water content (LWC) profile used in MODIS retrieval. With respect to AMSR-E LWP that acts as ground truth under a series of constraints, the global average of MODIS-LWPVH and MODIS-LWPAS has a positive (11.8%) and negative (-6.8%) bias, respectively. Most of the oceanic warm clouds tend to have adiabatic origin and correspondingly form AS-like profiles, which could be well retained if drizzle is absent. Besides, the presence of drizzle, cloud top entrainment seems to be another cause that modifies the original LWC profiles to become VH-like, which is notable for the very low clouds that have rather small thickness. These factors jointly determine the appearance of LWP profiles and in turn their spatial pattern across global oceans, with AS-like profiles dominant in the areas where nonraining warm clouds occur very frequently in the form of stratocumulus. The modified MODIS LWP shows significant improvement compared with either MODIS-LWPVH or MODIS-LWPAS. This is achieved by using the two physically explicit models flexibly, in which the elementary MODIS retrievals of cloud top temperature, cloud optical thickness, and droplet effective radius play a determinant role. A combined use of VH and AS model in the MODIS retrieval is demonstrated to be effective for improving the LWP estimation for oceanic nonraining warm clouds.

  14. Vertical aerosol structure of Neptune - Constraints from center-to-limb profiles

    NASA Astrophysics Data System (ADS)

    Hammel, H. B.; Baines, K. H.; Bergstralh, J. T.

    1989-08-01

    New center-to-limb (CTL) equatorial region profiles of Neptune have been extracted from spatially well-resolved images. The 8900-A CTL profile entails the presence of material above the 5-mbar level whose optical depth is less than 0.5. CH4-band data admit of thin scattering hazes in the 0.4-1.5 bar pressure level, although optical depths must be lower than 0.05; so thin a haze falls short of the reflected flux at 6340 A, thereby implying the presence of another scattering layer deeper than 1.5 bars. A good fit to the observed reflectivity is obtained by a bright cloud layer with an optical depth of 3.0.

  15. Vertical profiles of atmospheric fluorescent aerosols observed by a mutil-channel lidar spectrometer system

    NASA Astrophysics Data System (ADS)

    Huang, Z.; Huang, J.; Zhou, T.; Sugimoto, N.; Bi, J.

    2015-12-01

    Zhongwei Huang1*, Jianping Huang1, Tian Zhou1, Nobuo Sugimoto2, Jianrong Bi1 and Jinsen Shi11Key Laboratory for Semi-Arid Climate Change of the Ministry of Education, College of Atmospheric Sciences, Lanzhou University, Lanzhou, China. 2Atmospheric Environment Division, National Institutes for Environmental Studies, Tsukuba, Japan Email: huangzhongwei@lzu.edu.cn Abstract Atmospheric aerosols have a significant impact on regional and globe climate. The challenge in quantifying aerosol direct radiative forcing and aerosol-cloud interactions arises from large spatial and temporal heterogeneity of aerosol concentrations, compositions, sizes, shape and optical properties (IPCC, 2007). Lidar offers some remarkable advantages for determining the vertical structure of atmospheric aerosols and their related optical properties. To investigate the characterization of atmospheric aerosols (especially bioaerosols) with high spatial and temporal resolution, we developed a Raman/fluorescence/polarization lidar system employed a multi-channel spectrometer, with capabilities of providing measurements of Raman scattering and laser-induced fluorescence excitation at 355 nm from atmospheric aerosols. Meanwhile, the lidar system operated polarization measurements both at 355nm and 532nm wavelengths, aiming to obtain more information of aerosols. It employs a high power pulsed laser and a received telescope with 350mm diameter. The receiver could simultaneously detect a wide fluorescent spectrum about 178 nm with spectral resolution 5.7 nm, mainly including an F/3.7 Crossed Czerny-Turner spectrograph, a grating (1200 gr/mm) and a PMT array with 32 photocathode elements. Vertical structure of fluorescent aerosols in the atmosphere was observed by the developed lidar system at four sites across northwest China, during 2014 spring field observation that conducted by Lanzhou University. It has been proved that the developed lidar could detect the fluorescent aerosols with high temporal and

  16. Tropospheric Ozone Increases in the TTL over the Southern African Region (1990-2007): Insights from Sonde and Aircraft Profiles

    NASA Astrophysics Data System (ADS)

    Balashov, N. V.; Thompson, A. M.; Kollonige, D. E.; Coetzee, G.; Thouret, V.; Posny, F.

    2013-12-01

    Ozonesonde records from the early 1990s through 2007 over two subtropical stations, Irene (near Pretoria, South Africa) and Réunion Island (21S, 55W, ~3500 km NE of Irene in the southwest Indian Ocean) have been reported to exhibit free tropospheric (FT) ozone increases. We re-analyzed FT ozone in the1990-2007 Irene sondes, filling in mid-1990s gaps with ozone profiles taken by Measurements of Ozone by Airbus In-service Aircraft (MOZAIC) over nearby Johannesburg. We applied a multivariate regression model to monthly averaged data from the combined dataset as well as to 1992-2011 FT and TTL ozone from Réunion sondes. Taking into account terms for the seasonal cycle, ENSO, and potential vorticity (PV) anomalies, we found that: (1) Statistically significant trends appear predominantly in the middle troposphere up to the tropopause layer (6-11 km over Irene, 6-15 km over Réunion) in winter (June-August), with an increase ~ 1 ppbv/yr over Irene and ~2 ppbv/yr over Réunion. Both stations display a less intense ozone increase above 7 km in November-December. (2) Variability in TTL dynamics and stratosphere-troposphere interactions were considered as plausible explanations for the Irene ozone increases. For the spring, there is a pronounced sensitivity to PV anomalies (+ 70 ppbv ozone/PV unit). We compare these results to our prior study of TTL wave activity at Irene and Réunion and relationships among waves, TTL ozone variability and oscillations like the ENSO. Trend (change in ppbv ozone/year) computed from multivariate regression model for 4-15 km, profiles from Réunion sondes, 1992-2011. Diagonal shading denotes statistical significance.

  17. Vertical variations of soil hydraulic properties within two soil profiles and its relevance for soil water simulations

    NASA Astrophysics Data System (ADS)

    Schwen, Andreas; Zimmermann, Michael; Bodner, Gernot

    2014-08-01

    Numerical simulations of soil water dynamics can be valuable tools for the assessment of different soil and land management practices. For accurate simulations, the soil hydraulic properties (SHP), i.e. the hydraulic conductivity and water retention function have to be properly known. They can be either estimated from physical soil properties by pedotransfer functions (PTF) or measured. In most studies, soil profiles are analyzed and sampled with respect to their pedogenic horizons. While considerable effort has been put on horizontal spatial SHP variations, vertical changes within soil profiles have not been analyzed in detail. Therefore, the objectives of this study were (i) the SHP measurement along vertical transects within two soil profiles, (ii) to evaluate their spatial variation and correlation with physical soil properties, and (iii) to assess the impact of the SHP determination method and its spatial discretization on simulated soil water balance components. Two soils, an agriculturally used silty-loam Chernozem and a forested sandy Cambisol were sampled in 0.05 m increments along vertical transects. The parameters of a dual porosity model were derived using the evaporation method and scaling was applied to derive representative mean SHP parameters and scaling factors as a measure of spatial variability. State-space models described spatial variations of the scaling factors by physical soil properties. Simulations with HYDRUS 1D delivered the soil water balance for different climatic conditions with the SHP being estimated from horizon-wise PTFs, or discretized either sample-wise, according to the pedogenic horizons, or as hydrologically relevant units (hydropedological approach). Considerable SHP variations were found for both soil profiles. In the Chernozem, variations of the hydraulic conductivity were largest within the ploughed Ap-horizon and could be attributed to variations in soil structure (macropores). In the subsoil, soil water retention showed

  18. A New Inversion Routine to Produce Vertical Electron-Density Profiles from Ionospheric Topside-Sounder Data

    NASA Technical Reports Server (NTRS)

    Wang, Yongli; Benson, Robert F.

    2011-01-01

    Two software applications have been produced specifically for the analysis of some million digital topside ionograms produced by a recent analog-to-digital conversion effort of selected analog telemetry tapes from the Alouette-2, ISIS-1 and ISIS-2 satellites. One, TOPIST (TOPside Ionogram Scalar with True-height algorithm) from the University of Massachusetts Lowell, is designed for the automatic identification of the topside-ionogram ionospheric-reflection traces and their inversion into vertical electron-density profiles Ne(h). TOPIST also has the capability of manual intervention. The other application, from the Goddard Space Flight Center based on the FORTRAN code of John E. Jackson from the 1960s, is designed as an IDL-based interactive program for the scaling of selected digital topside-sounder ionograms. The Jackson code has also been modified, with some effort, so as to run on modern computers. This modification was motivated by the need to scale selected ionograms from the millions of Alouette/ISIS topside-sounder ionograms that only exist on 35-mm film. During this modification, it became evident that it would be more efficient to design a new code, based on the capabilities of present-day computers, than to continue to modify the old code. Such a new code has been produced and here we will describe its capabilities and compare Ne(h) profiles produced from it with those produced by the Jackson code. The concept of the new code is to assume an initial Ne(h) and derive a final Ne(h) through an iteration process that makes the resulting apparent-height profile fir the scaled values within a certain error range. The new code can be used on the X-, O-, and Z-mode traces. It does not assume any predefined profile shape between two contiguous points, like the exponential rule used in Jackson s program. Instead, Monotone Piecewise Cubic Interpolation is applied in the global profile to keep the monotone nature of the profile, which also ensures better smoothness

  19. Seasonal distribution of metals in vertical and horizontal profiles of sheltered and exposed beaches on Polish coast.

    PubMed

    Bigus, Katarzyna; Astel, Aleksander; Niedzielski, Przemysław

    2016-05-15

    The distribution of alkali and heavy metals in coastal sediments of three Polish beaches was assessed. In all locations there are sandy beaches of different characteristics according to the anthropogenic impact and degree of sheltering. Core sediments collected in Czołpino and Ustka were characterized by the highest concentration of Cd, Ag, Ba, and Al, Cu, Cr, Bi, Na, respectively. Among the alkaline metals core sediments were the most abundant with Ca, Bi, Mg and Na, presenting almost stable decreasing order in all beaches. The majority of dredge material collected can be classified as light or trace contaminated by Cr, Cu, Zn, Cd and Hg. An abundance of mineralogical components in core sediments in Ustka increases in Summer and Autumn, while in Puck is stable throughout the year. The content of studied metals in core sediments collected in three Polish beaches changes both in the vertical and horizontal profiles of the beach.

  20. Experimental observation of the influence of furnace temperature profile on convection and segregation in the vertical Bridgman crystal growth technique

    NASA Technical Reports Server (NTRS)

    Neugebauer, G. T.; Wilcox, W. R.

    1990-01-01

    Azulene-doped naphtalene was directionally solidified using the vertical Bridgman-Stockbarger technique. Doping homogeneity and convection are determined as a function of the temperature profile in the furnace and the freezing rate. Convective velocities are two orders of magnitude lower when the temperature increases with height. The cross sectional variation in azulene concentration tends to be asymmetric. Neither rotation of the ampoule nor deliberate introduction of thermal asymmetries during solidification had a significant influence on cross sectional variations in doping. It is predicted that slow directional solidification under microgravity conditions can produce greater inhomogeneities than on earth. Thus when low freezing rates are necessary in order to avoid constitutional supercooling, it may be necessary to combine microgravity and magnetic fields in order to achieve homogeneous crystals.

  1. Seasonal distribution of metals in vertical and horizontal profiles of sheltered and exposed beaches on Polish coast.

    PubMed

    Bigus, Katarzyna; Astel, Aleksander; Niedzielski, Przemysław

    2016-05-15

    The distribution of alkali and heavy metals in coastal sediments of three Polish beaches was assessed. In all locations there are sandy beaches of different characteristics according to the anthropogenic impact and degree of sheltering. Core sediments collected in Czołpino and Ustka were characterized by the highest concentration of Cd, Ag, Ba, and Al, Cu, Cr, Bi, Na, respectively. Among the alkaline metals core sediments were the most abundant with Ca, Bi, Mg and Na, presenting almost stable decreasing order in all beaches. The majority of dredge material collected can be classified as light or trace contaminated by Cr, Cu, Zn, Cd and Hg. An abundance of mineralogical components in core sediments in Ustka increases in Summer and Autumn, while in Puck is stable throughout the year. The content of studied metals in core sediments collected in three Polish beaches changes both in the vertical and horizontal profiles of the beach. PMID:26975611

  2. Vertical profiles of aerosol and black carbon in the Arctic: a seasonal phenomenology along 2 years (2011-2012) of field campaigns

    NASA Astrophysics Data System (ADS)

    Ferrero, Luca; Cappelletti, David; Busetto, Maurizio; Mazzola, Mauro; Lupi, Angelo; Lanconelli, Christian; Becagli, Silvia; Traversi, Rita; Caiazzo, Laura; Giardi, Fabio; Moroni, Beatrice; Crocchianti, Stefano; Fierz, Martin; Močnik, Griša; Sangiorgi, Giorgia; Perrone, Maria G.; Maturilli, Marion; Vitale, Vito; Udisti, Roberto; Bolzacchini, Ezio

    2016-10-01

    We present results from a systematic study of vertical profiles of aerosol number size distribution and black carbon (BC) concentrations conducted in the Arctic, over Ny-Ålesund (Svalbard). The campaign lasted 2 years (2011-2012) and resulted in 200 vertical profiles measured by means of a tethered balloon (up to 1200 m a.g.l.) during the spring and summer seasons. In addition, chemical analysis of filter samples, aerosol size distribution and a full set of meteorological parameters were determined at ground. The collected experimental data allowed a classification of the vertical profiles into different typologies, which allowed us to describe the seasonal phenomenology of vertical aerosol properties in the Arctic. During spring, four main types of profiles were found and their behavior was related to the main aerosol and atmospheric dynamics occurring at the measuring site. Background conditions generated homogenous profiles. Transport events caused an increase of aerosol concentration with altitude. High Arctic haze pollution trapped below thermal inversions promoted a decrease of aerosol concentration with altitude. Finally, ground-based plumes of locally formed secondary aerosol determined profiles with decreasing aerosol concentration located at different altitude as a function of size. During the summer season, the impact from shipping caused aerosol and BC pollution plumes to be constrained close to the ground, indicating that increasing shipping emissions in the Arctic could bring anthropogenic aerosol and BC in the Arctic summer, affecting the climate.

  3. Vertical profile of δ18OOO from middle stratosphere to lower mesosphere derived by retrieval algorithm developed for SMILES spectra

    NASA Astrophysics Data System (ADS)

    Sato, T. O.; Sagawa, H.; Yoshida, N.; Kasai, Y.

    2013-10-01

    Ozone is known to have large oxygen isotopic enrichments of about 10 % in the middle stratosphere, however, there have been no reports on ozone isotopic enrichments above the middle stratosphere. We derived an enrichment δ18OOO by a retrieval algorithm specified for the isotopic ratio from the stratosphere to the lower mesosphere based on observations from the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) onboard the International Space Station (ISS). The retrieval algorithm includes (i) an a priori covariance matrix constrained by oxygen isotopic ratios in ozone, (ii) an optimization of spectral windows for ozone isotopomers and isotopologues, and (iii) a common tangent height information for all windows. The δ18OOO obtained by averaging the SMILES measurements at the latitude range of 20° N to 40° N from February to March in 2010 with solar zenith angle <80° was 15% (at 32 km) and the systematic error was estimated to be about 5%. SMILES and past measurements were in good agreement with δ18OOO increasing with altitude between 30 and 40 km. The vertical profile of δ18OOO obtained in this study showed an increase and a decrease with altitude in the stratosphere and mesosphere, respectively. Stratopause is the peak-height of the δ18OOO value, and it rose to 18%. The δ18OOO has a positive correlation with temperature in the range of 220-255 K, indicating that temperature can be a dominant factor to control the vertical profile of δ18OOO in the stratosphere and mesosphere. This is the first report of the observation of δ18OOO over a wide range extending from the stratosphere to the mesosphere.

  4. Vertical profile of delta 18000 from middle stratosphere to lower mesosphere derived by retrieval algorithm developed for SMILES spectra

    NASA Astrophysics Data System (ADS)

    Kasai, Yasuko; Sato, Tomohiro; Sagawa, Hideo

    Ozone is known to have large oxygen isotopic enrichments of about 10% in the middle stratosphere, however, there have been no reports on ozone isotopic enrichments above the middle stratosphere. We derived an enrichment delta18OOO by a retrieval algorithm specified for the isotopic ratio from the stratosphere to the lower mesosphere based on observations from the Superconducting Submillimeter-Wave Limb-Emission Sounder (SMILES) onboard the International Space Station (ISS). The retrieval algorithm includes (i) an a priori covariance matrix constrained by oxygen isotopic ratios in ozone, (ii) an optimization of spectral windows for ozone isotopomers and isotopologues, and (iii) a common tangent height information for all windows. The delta18OOO obtained by averaging the SMILES measurements at the latitude range of 20N to 40N from February to March in 2010 with solar zenith angle less than 80(°) °was 15 % (at 32 km) and the systematic error was estimated to be about 5 percent. SMILES and past measurements were in good agreement with delta18OOO increasing with altitude between 30 and 40 km. The vertical profile of δ18OOO obtained in this study showed an increase and a decrease with altitude in the stratosphere and mesosphere, respectively. Stratopause is the peak-height of the delta18OOO value, and it rose to 18 %. The delta18OOO has a positive correlation with temperature in the range of 220-255 K, indicating that temperature can be a dominant factor to control the vertical profile of delta18OOO in the stratosphere and mesosphere. This is the first report of the observation of delta18OOO over a wide range extending from the stratosphere to the mesosphere.

  5. Assessing the microbial community and functional genes in a vertical soil profile with long-term arsenic contamination.

    PubMed

    Xiong, Jinbo; He, Zhili; Van Nostrand, Joy D; Luo, Guosheng; Tu, Shuxin; Zhou, Jizhong; Wang, Gejiao

    2012-01-01

    Arsenic (As) contamination in soil and groundwater has become a serious problem to public health. To examine how microbial communities and functional genes respond to long-term arsenic contamination in vertical soil profile, soil samples were collected from the surface to the depth of 4 m (with an interval of 1 m) after 16-year arsenic downward infiltration. Integrating BioLog and functional gene microarray (GeoChip 3.0) technologies, we showed that microbial metabolic potential and diversity substantially decreased, and community structure was markedly distinct along the depth. Variations in microbial community functional genes, including genes responsible for As resistance, carbon and nitrogen cycling, phosphorus utilization and cytochrome c oxidases were detected. In particular, changes in community structures and activities were correlated with the biogeochemical features along the vertical soil profile when using the rbcL and nifH genes as biomarkers, evident for a gradual transition from aerobic to anaerobic lifestyles. The C/N showed marginally significant correlations with arsenic resistance (p = 0.069) and carbon cycling genes (p = 0.073), and significant correlation with nitrogen fixation genes (p = 0.024). The combination of C/N, NO(3) (-) and P showed the highest correlation (r = 0.779, p = 0.062) with the microbial community structure. Contradict to our hypotheses, a long-term arsenic downward infiltration was not the primary factor, while the spatial isolation and nutrient availability were the key forces in shaping the community structure. This study provides new insights about the heterogeneity of microbial community metabolic potential and future biodiversity preservation for arsenic bioremediation management.

  6. The results of complex optical measurements of vertical temperature profile of the atmos-phere in the winter in Yakutsk

    NASA Astrophysics Data System (ADS)

    Nikolashkin, Semyen; Ignatyev, V. M.; Ammosov, Petr; Koltovskoy, Igor; Titov, Semen; Reshetnikov, Alexander

    The results of simultaneous measurements of atmospheric temperature from 0 to 100 km by lidar, spectrometric and interferometric methods in winter 2008 in Yakutsk are presented. Temperature measurements for the surface layer from 0 to 20-25 km were obtained from radio-sonde data on upper-air station in Yakutsk. Measuring the temperature of the middle atmosphere from 25 to 55-60 km made using Rayleigh Lidar near Yakutsk, with the following parameters: a transmitter Nd-YAG laser at a wavelength of 532 nm and a pulse energy of 200 mJ receiver - a telescope with a primary mirror diameter of 60 cm and a focal length of 200 cm, with a photon counting system and a spectrum analyzer. The temperature of the upper atmosphere was meas-ured at three altitude levels: by hydroxyl emission layer at the mesopause (6,2 band) , molecular oxygen radiation using an infrared spectrograph with a CCD camera and atomic oxygen emission line 557.7 nm with Fabry-Perot spectrometer (FPS) at the Maimaga optic range. FPS aperture was 15 cm, gap 1.5 cm, plate’s reflectance 0.85 and finess12. Thus, in this work, we covered by the temperature measuring most of the atmosphere ex-cept for a layer of the mesosphere from 60 to 87 km. For comparison, also are used CIRA model and the AURA MLS instrument (MicroLimb Sounder) temperature profiles data. Data analysis showed that there is a wave-like change in the vertical temperature profile, which is the result of vertical transmission features planetary waves during a stratospheric warming. This work is supported by the Integration project of the SB RAS No. 106 and RFBR grant No. 12-05-98547-r-vostok-a.

  7. NO 2 vertical profiles retrieved from ground-based measurements during spring 1999 in the Canadian Arctic

    NASA Astrophysics Data System (ADS)

    Melo, Stella M. L.; Farahani, E.; Strong, K.; Bassford, M. R.; Preston, K. E.; McLinden, C. A.

    2004-01-01

    During the 1990s, Arctic stratospheric temperatures were lower and the breakup of the Arctic vortex occurred later than has been observed in earlier decades. These cold winters have been followed by significant ozone loss. A clear identification of all the processes involved in springtime Arctic ozone depletion is complicated by the strong coupling between transport, formation of solid and liquid aerosols, and halogen activation. One of the key chemical species in the photochemistry of ozone is NO 2. As the role of NO 2 is strongly dependent on altitude, it is desirable to know not only the NO 2 total column, but also its vertical distribution. We have a portable UV-Vis grating spectrometer that was deployed at Eureka, Canada (80.1°N, 86.4°W) in spring 1999, 2000, 2001, and 2003, and at Resolute Bay, Canada (74.7°N, 94.6°W) in spring 2002. Eureka is part of the Arctic primary station of the Network for the Detection of Stratospheric Change. Among other species, the spectrometer measures stratospheric NO 2 through observation of sunlight scattered from the zenith sky during twilight. Due to the scattering geometry, the NO 2 slant column increases with solar zenith angle (SZA), making it possible to retrieve information about the vertical distribution of NO 2 from the observed slant column variation with SZA. In this paper, we use the optimal estimation technique with a formal characterization of the errors to retrieve NO 2 concentration profiles from slant column observations made at Eureka during March and April 1999. Such measurements can also be used in the validation of NO 2 profile measurements made by satellite instruments.

  8. Assessing the Microbial Community and Functional Genes in a Vertical Soil Profile with Long-Term Arsenic Contamination

    PubMed Central

    Xiong, Jinbo; He, Zhili; Van Nostrand, Joy D.; Luo, Guosheng; Tu, Shuxin; Zhou, Jizhong; Wang, Gejiao

    2012-01-01

    Arsenic (As) contamination in soil and groundwater has become a serious problem to public health. To examine how microbial communities and functional genes respond to long-term arsenic contamination in vertical soil profile, soil samples were collected from the surface to the depth of 4 m (with an interval of 1 m) after 16-year arsenic downward infiltration. Integrating BioLog and functional gene microarray (GeoChip 3.0) technologies, we showed that microbial metabolic potential and diversity substantially decreased, and community structure was markedly distinct along the depth. Variations in microbial community functional genes, including genes responsible for As resistance, carbon and nitrogen cycling, phosphorus utilization and cytochrome c oxidases were detected. In particular, changes in community structures and activities were correlated with the biogeochemical features along the vertical soil profile when using the rbcL and nifH genes as biomarkers, evident for a gradual transition from aerobic to anaerobic lifestyles. The C/N showed marginally significant correlations with arsenic resistance (p = 0.069) and carbon cycling genes (p = 0.073), and significant correlation with nitrogen fixation genes (p = 0.024). The combination of C/N, NO3− and P showed the highest correlation (r = 0.779, p = 0.062) with the microbial community structure. Contradict to our hypotheses, a long-term arsenic downward infiltration was not the primary factor, while the spatial isolation and nutrient availability were the key forces in shaping the community structure. This study provides new insights about the heterogeneity of microbial community metabolic potential and future biodiversity preservation for arsenic bioremediation management. PMID:23226297

  9. Double Bright Band Observations with High-Resolution Vertically Pointing Radar, Lidar, and Profiles

    NASA Technical Reports Server (NTRS)

    Emory, Amber E.; Demoz, Belay; Vermeesch, Kevin; Hicks, Michael

    2014-01-01

    On 11 May 2010, an elevated temperature inversion associated with an approaching warm front produced two melting layers simultaneously, which resulted in two distinct bright bands as viewed from the ER-2 Doppler radar system, a vertically pointing, coherent X band radar located in Greenbelt, MD. Due to the high temporal resolution of this radar system, an increase in altitude of the melting layer of approximately 1.2 km in the time span of 4 min was captured. The double bright band feature remained evident for approximately 17 min, until the lower atmosphere warmed enough to dissipate the lower melting layer. This case shows the relatively rapid evolution of freezing levels in response to an advancing warm front over a 2 h time period and the descent of an elevated warm air mass with time. Although observations of double bright bands are somewhat rare, the ability to identify this phenomenon is important for rainfall estimation from spaceborne sensors because algorithms employing the restriction of a radar bright band to a constant height, especially when sampling across frontal systems, will limit the ability to accurately estimate rainfall.

  10. Vertical profiles of dust and ozone in the Martian atmosphere deduced from solar occultation measurements

    NASA Astrophysics Data System (ADS)

    Blamont, J. E.; Chassefiere, E.; Goutail, J. P.; Mege, B.; Nunes-Pinharanda, M.; Souchon, G.; Krasnopolsky, V. A.; Krysko, A. A.; Moroz, V. I.

    1991-02-01

    The vertical distribution of the ozone content and of the aerosols in the Martian atmosphere at the equinox and near the equator was studied with the aid of a biaxial pointing device, a microprocessor-controlled flat mirror of elliptical shape. An upper limit of 5 x 10 to the 7th mol/cu cm for ozone was obtained above an altitude of 30 km. For the aerosols, a semiquantitative distribution has been obtained between 10 and 50 km of altitude. The scale height is nearly equal to the atmospheric scale height in the 10-20 km region where mixing seems to predominate, and falls rapidly to a thickness of about 2 km at 30 km. In 10 percent of the occultations, a stratified haze has been detected between 40 and 50 km. The particle radius of cloud constituents is estimated and optical thickness per kilometer of these hazes at peak extinction are approximated. An eddy diffusion coefficient and a mixing ratio are estimated for clouds assumed to be at equilibrium.

  11. Analytical solution to transient Richards' equation with realistic water profiles for vertical infiltration and parameter estimation

    NASA Astrophysics Data System (ADS)

    Hayek, Mohamed

    2016-06-01

    A general analytical model for one-dimensional transient vertical infiltration is presented. The model is based on a combination of the Brooks and Corey soil water retention function and a generalized hydraulic conductivity function. This leads to power law diffusivity and convective term for which the exponents are functions of the inverse of the pore size distribution index. Accordingly, the proposed analytical solution covers many existing realistic models in the literature. The general form of the analytical solution is simple and it expresses implicitly the depth as function of water content and time. It can be used to model infiltration through semi-infinite dry soils with prescribed water content or flux boundary conditions. Some mathematical expressions of practical importance are also derived. The general form solution is useful for comparison between models, validation of numerical solutions and for better understanding the effect of some hydraulic parameters. Based on the analytical expression, a complete inverse procedure which allows the estimation of the hydraulic parameters from water content measurements is presented.

  12. Improving the instantaneous vertical profiling of precipitation for passive-microwave retrievals

    NASA Astrophysics Data System (ADS)

    Kacimi, S.; Haddad, Z. S.; Turk, J.

    2013-12-01

    Current passive-microwave retrieval approaches that are based on the a-priori knowledge provided by a representative database of columns of atmospheric variables and their corresponding microwave signatures, depend crucially on the realism of the representation of the cloud and precipitation in the column. Most approaches rely on columns produced by cloud-permitting model simulations, which suffer from oversimplifications of the very variables to which the microwave brightness temperatures are most sensitive, namely the type, concentration and relative sizes of the hydrometeors. Others rely on retrieved descriptions obtained from imperfect remotely-sensed measurements. The TRMM radar being a single-channel instrument cannot, by itself identify the phase of the condensation. The GPM radar that offers an additional Ka-band frequency should be slightly better. This presentation will summarize our approach of using higher-sensitivity ground-based measurements to address these shortcomings. During the CINDY-DYNAMO experiment (2011-2012), the dual-wavelength polarimetric radar SPolKa was deployed, providing a unique set of observations. This allows insight into rainfall characteristics for different species. Using a Bayesian approach with Mie-scattering calculations, the rainfall rate, cloud liquid water, mean diameter and other parameters can be retrieved from SPolKa data. Different assumptions (on hydrometeor habit and size distributions) for those simulations were used, and their impact on the retrievals evaluated. This preliminary study will eventually enable the elaboration of a passive-microwave retrievals' database, accounting for the quantitative vertical distribution of precipitation.

  13. Methane production potentials, pathways, and communities of methanogens in vertical sediment profiles of river Sitka

    PubMed Central

    Mach, Václav; Blaser, Martin B.; Claus, Peter; Chaudhary, Prem P.; Rulík, Martin

    2015-01-01

    Biological methanogenesis is linked to permanent water logged systems, e.g., rice field soils or lake sediments. In these systems the methanogenic community as well as the pathway of methane formation are well-described. By contrast, the methanogenic potential of river sediments is so far not well-investigated. Therefore, we analyzed (a) the methanogenic potential (incubation experiments), (b) the pathway of methane production (stable carbon isotopes and inhibitor studies), and (c) the methanogenic community composition (terminal restriction length polymorphism of mcrA) in depth profiles of sediment cores of River Sitka, Czech Republic. We found two depth-related distinct maxima for the methanogenic potentials (a) The pathway of methane production was dominated by hydrogenotrophic methanogenesis (b) The methanogenic community composition was similar in all depth layers (c) The main TRFs were representative for Methanosarcina, Methanosaeta, Methanobacterium, and Methanomicrobium species. The isotopic signals of acetate indicated a relative high contribution of chemolithotrophic acetogenesis to the acetate pool. PMID:26052322

  14. Methane production potentials, pathways, and communities of methanogens in vertical sediment profiles of river Sitka.

    PubMed

    Mach, Václav; Blaser, Martin B; Claus, Peter; Chaudhary, Prem P; Rulík, Martin

    2015-01-01

    Biological methanogenesis is linked to permanent water logged systems, e.g., rice field soils or lake sediments. In these systems the methanogenic community as well as the pathway of methane formation are well-described. By contrast, the methanogenic potential of river sediments is so far not well-investigated. Therefore, we analyzed (a) the methanogenic potential (incubation experiments), (b) the pathway of methane production (stable carbon isotopes and inhibitor studies), and (c) the methanogenic community composition (terminal restriction length polymorphism of mcrA) in depth profiles of sediment cores of River Sitka, Czech Republic. We found two depth-related distinct maxima for the methanogenic potentials (a) The pathway of methane production was dominated by hydrogenotrophic methanogenesis (b) The methanogenic community composition was similar in all depth layers (c) The main TRFs were representative for Methanosarcina, Methanosaeta, Methanobacterium, and Methanomicrobium species. The isotopic signals of acetate indicated a relative high contribution of chemolithotrophic acetogenesis to the acetate pool.

  15. Vertical profile of branch CO2 efflux in a Norway spruce tree: a case study

    NASA Astrophysics Data System (ADS)

    Acosta, M.; Pavelka, M.

    2012-04-01

    Despite woody-tissue CO2 effluxes having been recognized as an important component of forest carbon budget due to the fraction of assimilates used and the dramatic increase in woody with stand development, there is limited research to determine the CO2 efflux vertical variability of woody-tissue components. For a better understanding and quantification of branch woody-tissue CO2 efflux in forest ecosystems, it is necessary to identify the environmental factors influencing it and the role of the branch distribution within the canopy. The proper assessment of this forest component will improve the knowledge of the ratio between ecosystem respiration and gross primary production at forest ecosystem. In order to achieve this goal, branch CO2 efflux of Norway spruce tree was measured in ten branches at five different whorls during the growing season 2004 (from June till October) in campaigns of 3-4 times per month at the Beskydy Mts., the Czech Republic, using a portable infrared gas analyzer operating as a closed system. Branch woody tissue temperature was measured continuously in ten minutes intervals for each sample position during the whole experiment period. On the basis of relation between CO2 efflux rate and woody tissue temperature a value of Q10 and normalized CO2 efflux rate (E10 - CO2 efflux rate at 10° C) were calculated for each sampled position. Estimated Q10 values ranged from 2.12 to 2.89 and E10 ranged from 0.41 to 1.19 ?molCO2m-2 s-1. Differences in branch CO2 efflux were found between orientations; East side branches presented higher efflux rate than west side branches. The highest branch CO2 efflux rate values were measured in August and the lowest in October, which were connected with woody tissue temperature and ontogenetic processes during these periods. Branch CO2 efflux was significantly and positively correlated with branch position within canopy and woody tissue temperature. Branches from the upper whorls showed higher respiration activity

  16. Combined analysis of surface reflection imaging and vertical seismic profiling at Yucca Mountain, Nevada

    SciTech Connect

    Daley, T.M.; Majer, E.L.; Karageorgi, E.

    1994-08-01

    This report presents results from surface and borehole seismic profiling performed by the Lawrence Berkeley Laboratory (LBL) on Yucca Mountain. This work was performed as part of the site characterization effort for the potential high-level nuclear waste repository. Their objective was to provide seismic imaging from the near surface (200 to 300 ft. depth) to the repository horizon and below, if possible. Among the issues addressed by this seismic imaging work are location and depth of fracturing and faulting, geologic identification of reflecting horizons, and spatial continuity of reflecting horizons. The authors believe their results are generally positive, with tome specific successes. This was the first attempt at this scale using modem seismic imaging techniques to determine geologic features on Yucca Mountain. The principle purpose of this report is to present the interpretation of the seismic reflection section in a geologic context. Three surface reflection profiles were acquired and processed as part of this study. Because of environmental concerns, all three lines were on preexisting roads. Line 1 crossed the mapped surface trace of the Ghost Dance fault and it was intended to study the dip and depth extent of the fault system. Line 2 was acquired along Drill Hole wash and was intended to help the ESF north ramp design activities. Line 3 was acquired along Yucca Crest and was designed to image geologic horizons which were thought to be less faulted along the ridge. Unfortunately, line 3 proved to have poor data quality, in part because of winds, poor field conditions and limited time. Their processing and interpretation efforts were focused on lines 1 and 2 and their associated VSP studies.

  17. Evaluation of Vertical Lacunarity Profiles in Forested Areas Using Airborne Laser Scanning Point Clouds

    NASA Astrophysics Data System (ADS)

    Székely, B.; Kania, A.; Standovár, T.; Heilmeier, H.

    2016-06-01

    The horizontal variation and vertical layering of the vegetation are important properties of the canopy structure determining the habitat; three-dimensional (3D) distribution of objects (shrub layers, understory vegetation, etc.) is related to the environmental factors (e.g., illumination, visibility). It has been shown that gaps in forests, mosaic-like structures are essential to biodiversity; various methods have been introduced to quantify this property. As the distribution of gaps in the vegetation is a multi-scale phenomenon, in order to capture it in its entirety, scale-independent methods are preferred; one of these is the calculation of lacunarity. We used Airborne Laser Scanning point clouds measured over a forest plantation situated in a former floodplain. The flat topographic relief ensured that the tree growth is independent of the topographic effects. The tree pattern in the plantation crops provided various quasi-regular and irregular patterns, as well as various ages of the stands. The point clouds were voxelized and layers of voxels were considered as images for two-dimensional input. These images calculated for a certain vicinity of reference points were taken as images for the computation of lacunarity curves, providing a stack of lacunarity curves for each reference points. These sets of curves have been compared to reveal spatial changes of this property. As the dynamic range of the lacunarity values is very large, the natural logarithms of the values were considered. Logarithms of lacunarity functions show canopy-related variations, we analysed these variations along transects. The spatial variation can be related to forest properties and ecology-specific aspects.

  18. On the Vertical Gradient in CO2

    NASA Astrophysics Data System (ADS)

    Stine, A. R.; Fung, I. Y.

    2008-12-01

    Attempts to constrain surface fluxes of carbon from atmospheric measurements of carbon dioxide have primarily focused on surface boundary layer measurements, because information about surface fluxes is least diluted close to the locations where the fluxes occur. However, errors in model ventilation of air in the vertical can be misinterpreted as local surface fluxes. Satellites which measure column integrated CO2 are expected to represent a major advance in part because they observe the entire atmospheric column. Recent work has highlighted the fact that vertical gradients in carbon concentrations can give us information about where vertical mixing errors are likely to be misinterpreted as local surface fluxes, but passive tracer evidence suggests that models that capture vertical profiles on the ocean do poorly on the land (and vice versa), suggesting that the problem of correctly treating vertical mixing in inverse studies is more fundamental than picking the "best" model. We consider observations of the vertical gradient in CO2 from aircrafts and from a comparison of satellites that observe in the near infrared (which observe the column integrated CO2 field) and the thermal infrared (which observe the upper troposphere). We evaluate the feasibility of using these satellites for determining the vertical gradient in CO2. We examine how observations of the vertical gradient of CO2 allow us to differentiate the imprint of vertical mixing and the imprint in surface fluxes on the observed field of atmospheric CO2.

  19. Depth-profiling of vertical sidewall nanolayers on structured wafers by grazing incidence X-ray flourescence

    NASA Astrophysics Data System (ADS)

    Hönicke, P.; Beckhoff, B.; Kolbe, M.; List, S.; Conard, T.; Struyff, H.

    2008-12-01

    The Physikalisch-Technische Bundesanstalt (PTB), Germany's national metrology institute, developed an alignment strategy to specify elemental depth profiling in vertical sidewall layers on structured wafers. For this purpose, PTB's irradiation chamber for 200 mm and 300 mm silicon wafers was used to combine total-reflection X-ray fluorescence (TXRF) and grazing incidence XRF (GIXRF) techniques by employing monochromatized undulator radiation of the BESSY II electron storage ring. 3-D test structures were fabricated to develop an optimal alignment strategy allowing for depth profiling in such nanolayers. The test structures consisted of silicon bars with widths/spacings either in the μm or in the nm range. In order to be able to differentiate the sidewalls more easily from the remainder of the structures, they were provided with an additional silicon nitride layer. Four structure types of different bar width and density parameters on two 200 mm silicon wafers were investigated. The alignment procedure developed in the present work consists of three main steps and allows for distinct excitation of multiple sidewalls of one kind. Information about depth-dependent sidewall contamination, layer thickness and composition can be obtained by this approach. First results obtained on these test structures demonstrate the application potential of this new technique. In principle, depth-dependent chemical speciation should also be possible using GIXRF in combination with near edge absorption X-ray fine structure (NEXAFS).

  20. Water vapor on Titan: the stratospheric vertical profile from Cassini/CIRS infrared spectra

    NASA Astrophysics Data System (ADS)

    Cottini, V.; Jennings, D. E.; Nixon, C. A.; Anderson, C. M.; Gorius, N.; Bjoraker, G. L.; Coustenis, A.; Achterberg, R. K.; Teanby, N. A.; de Kok, R.; Irwin, P. G. J.; Bézard, B.; Lellouch, E.; Flasar, F. M.; Bampasidis, G.

    2012-04-01

    Water vapor in Titan’s middle atmosphere has previously been detected only by disk-average observations from the Infrared Space Observatory (Coustenis et al., 1998). We report here the successful detection of stratospheric water vapor using the Cassini Composite Infrared Spectrometer (CIRS, Flasar et al., 2004) following an earlier null result (de Kok et al., 2007a). CIRS senses water emissions in the far-infrared spectral region near 50 microns, which we have modeled using two independent radiative transfer and inversion codes (NEMESIS, Irwin et al 2008 and ART, Coustenis et al., 2010). From the analysis of nadir spectra we have derived a mixing ratio of (0.14 ± 0.05) ppb at 100 km, corresponding to a column abundance of approximately (3.7 ± 1.3) × 10^14 mol/cm2. Using limb observations, we obtained mixing ratios of (0.13 ± 0.04) ppb at 125 km and (0.45 ± 0.15) ppb at 225 km of altitude, confirming that the water abundance has a positive vertical gradient as predicted by photochemical models. In the latitude range (80˚S - 30˚N) we see no evidence for latitudinal variations in these abundances within the error bars. References: Coustenis, A.; Salama, A.; Lellouch, E.; Encrenaz, Th.; Bjoraker, G. L.; Samuelson, R. E.; de Graauw, Th.; Feuchtgruber, H.; Kessler, M. F., 1998. Evidence for water vapor in Titan's atmosphere from ISO/SWS data. Astronomy and Astrophysics, v.336, p.L85-L89 Coustenis, A.; Jennings, D. E.; Nixon, C. A.; Achterberg, R. K.; Lavvas, P.; Vinatier, S.; Teanby, N. A.; Bjoraker, G. L.; Carlson, R. C.; Piani, L.; Bampasidis, G.; Flasar, F. M.; Romani, P. N., 2010. Titan trace gaseous composition from CIRS at the end of the Cassini-Huygens prime mission. Icarus, Volume 207, Issue 1, p. 461-476. de Kok, R.; Irwin, P. G. J.; Teanby, N. A.; Lellouch, E.; Bézard, B.; Vinatier, S.; Nixon, C. A.; Fletcher, L.; Howett, C.; Calcutt, S. B.; Bowles, N. E.; Flasar, F. M.; Taylor, F. W. , 2007a. Oxygen compounds in Titan's stratosphere as observed by

  1. Vertical and Horizontal Corneal Epithelial Thickness Profile Using Ultra-High Resolution and Long Scan Depth Optical Coherence Tomography

    PubMed Central

    Jiang, Hong; Xu, Zhe; Perez, Victor; Wang, Jianhua

    2014-01-01

    Purpose To determine the vertical and horizontal thickness profiles of the corneal epithelium in vivo using ultra-long scan depth and ultra-high resolution spectral domain optical coherence tomography (SD-OCT). Methods A SD-OCT was developed with an axial resolution of ∼3.3 µm in tissue and an extended scan depth. Forty-two eyes of 21 subjects were imaged twice. The entire horizontal and vertical corneal epithelial thickness profiles were evaluated. The coefficient of repeatability (CoR) and intraclass correlation (ICC) of the tests and interobserver variability were analyzed. Results The full width of the horizontal epithelium was detected, whereas part of the superior epithelium was not shown for the covered super eyelid. The mean central epithelial corneal thickness was 52.0±3.2 µm for the first measurement and 52.3±3.4 µm for the second measurement (P>.05). In the central zone (0–3.0 mm), the paracentral zones (3.0–6.0 mm) and the peripheral zones (6.0–10.0 mm), the mean epithelial thickness ranged from 51 to 53 µm, 52 to 57 µm, and 58 to 72 µm, respectively. There was no difference between the two tests at both meridians and in the right and left eyes (P>.05). The ICCs of the two tests ranged from 0.70 to 0.97 and the CoRs ranged from 2.5 µm to 7.8 µm from the center to the periphery, corresponding to 5.6% to 10.6% (CoR%). The ICCs of the two observers ranged from 0.72 to 0.93 and the CoRs ranged from 4.5 µm to 10.4 µm from the center to the periphery, corresponding to 8.7% to 15.2% (CoR%). Conclusions This study demonstrated good repeatability of ultra-high resolution and long scan depth SD-OCT to evaluate the entire thickness profiles of the corneal epithelium. The epithelial thickness increases from the center toward the limbus. PMID:24844566

  2. 3.5kHz Profiling with Vertically Separated Source and Receiver

    NASA Astrophysics Data System (ADS)

    Bolmer, S. T.; Hoskins, H.; Stephen, R. A.; Leg 200 Shipboard Scientific Party, .

    2003-12-01

    The spatial resolution of hull mounted 3.5kHz echo sounding systems is often limited in deep water by the large footptint (Fresnel zone) of the insonifying energy on the seafloor. On ODP Leg 200 at Site 1224, we tested a system that could be used from the drillship while on station to improve resolution. In 4970 m water depth, a 3.5 kHz pinger was mounted on the video camera frame and lowered down the drill string to a few meters above the seafloor. The ship's 3.5 kHz receiver recorded the returns. Having the source and receiver at differing distances above the seafloor provides two advantages: 1) the area returning reflections is greatly reduced, 2) the amplitudes of the sub-seafloor reflections are less affected by the spreading effect. Reflections were observed to 38 ms beneath the seafloor on lowerings at three closely spaced holes. The heave of the ship and camera frame shifted the travel times of the reflection sequences. A level-discriminator and correlation MatLab routine was used to align the traces and to stack them to enhance signal. The reflections showed good correlation with the limited geotechnical data obtained from the sediment cores. Although tested from the drill ship this system could be used to provide a low cost, shallow penetration profiling system from ROV's and AUV's. This work was supported by a grant from JOI-USSAC.

  3. Monitoring atmospheric turbulence profiles with high vertical resolution using PML/PBL instrument

    NASA Astrophysics Data System (ADS)

    Blary, F.; Ziad, A.; Borgnino, J.; Fantéï-Caujolle, Y.; Aristidi, Eric; Lantéri, H.

    2014-07-01

    Wide-Field Adaptive Optics (WFAO) have been proposed for the next generation of telescopes. In order to be efficient, correction using WFAO require knowledge of atmospheric turbulence parameters. The structure constant of index-of-refraction fluctuations (C2 N ) being one of them. Indirect methods implemented in instruments as SCIDAR, MASS, SLODAR, CO-SLIDAR and MOSP have been proposed to measure C2 N (h) pro le through different layers of the atmosphere. A new monitor called the Profiler of Moon Limb (PML) is presented. In this instrument, C2 N (h) pro les are retrieved from the transverse covariance via minimization of a maximum likelihood criterion under positivity constraint using an iterative gradient method. An other approach using a regularization method (RM) is also studied. Instrument errors are mainly related to the detection of the Moon limb position and are mostly due to photon noise. Numerical simulations have been used to evaluate the error on the extracted pro le and its propagation from the detection to the inverse technique.

  4. Stable carbon and nitrogen isotopes in vertical peat profiles of natural and drained boreal peatlands

    NASA Astrophysics Data System (ADS)

    Nykänen, Hannu; Mpamah, Promise; Rissanen, Antti; Pitkänen, Aki; Turunen, Jukka; Simola, Heikki

    2015-04-01

    Peatlands form a significant carbon pool in the global carbon cycle. Change in peat hydrology, due to global warming is projected to change microbiological processes and peat carbon pool. We tested if bulk stable carbon and nitrogen isotopes serve as indicators of severe long term drying in peatlands drained for forestry. Depth profile analysis of peat, for their carbon and nitrogen content as well as their carbon and nitrogen stable isotopic signatures, were conducted for peatlands in southern and eastern Finland, having ombrotrophic and minerotrophic natural and corresponding drained pairs or separate drained sites. The selection of sites allowed us to compare changes due to different fertility and changes due to long term artificial drying. Drainage lasting over 40 years has led to changes in hydrology, vegetation, nutrient mineralization and respiration. Furthermore, increased nutrient uptake and possible recycling of peat nitrogen and carbon trough vegetation back to the peat surface, also possibly has an effect on the stable isotopic composition of peat carbon and nitrogen. We think that drainage induced changes somehow correspond to those caused by changed hydrology due to climate change. We will present data from these measurements and discuss their implications for carbon and nitrogen flows in peatlands.

  5. Vertical profile of H 2SO 4 vapor at 70-110 km on Venus and some related problems

    NASA Astrophysics Data System (ADS)

    Krasnopolsky, Vladimir A.

    2011-09-01

    The vertical profile of H 2SO 4 vapor is calculated using current atmospheric and thermodynamic data. The atmospheric data include the H 2O profiles observed at 70-112 km by the SOIR solar occultations, the SPICAV-UV profiles of the haze extinction at 220 nm, the VeRa temperature profiles, and a typical profile of eddy diffusion. The thermodynamic data are the saturated vapor pressures of H 2O and H 2SO 4 and chemical potentials of these species in sulfuric acid solutions. The calculated concentration of sulfuric acid in the cloud droplets varies from 85% at 70 km to a minimum of 70% at 90 km and then gradually increasing to 90-100% at 110 km. The H 2SO 4 vapor mixing ratio is ˜10 -12 at 70 and 110 km with a deep minimum of 3 × 10 -18 at 88 km. The H 2O-H 2SO 4 system matches the local thermodynamic equilibrium conditions up to 87 km. The column photolysis rate of H 2SO 4 is 1.6 × 10 5 cm -2 s -1 at 70 km and 23 cm -2 s -1 at 90 km. The calculated abundance of H 2SO 4 vapor at 90-110 km and its photolysis rate are smaller than those presented in the recent model by Zhang et al. (Zhang, X., Liang, M.C., Montmessin, F., Bertaux, J.L., Parkinson, C., Yung, Y.L. [2010]. Nat. Geosci. 3, 834-837) by factors of 10 6 and 10 9, respectively. Assumptions of 100% sulfuric acid, local thermodynamic equilibrium, too warm atmosphere, supersaturation of H 2SO 4 (impossible for a source of SO X), and cross sections for H 2SO 4·H 2O (impossible above the pure H 2SO 4) are the main reasons of this huge difference. Significant differences and contradictions between the SPICAV-UV, SOIR, and ground-based submillimeter observations of SO X at 70-110 km are briefly discussed and some weaknesses are outlined. The possible source of high altitude SO X on Venus remains unclear and probably does not exist.

  6. Characteristics of internal waves in the Martian atmosphere obtained on the basis of an analysis of vertical temperature profiles of the Mars Global Surveyor mission

    NASA Astrophysics Data System (ADS)

    Gubenko, V. N.; Kirillovich, I. A.; Pavelyev, A. G.

    2015-03-01

    An original method of determining the characteristics of an internal gravity wave (IGW) was developed using the data of an analysis of individual vertical temperature profile in the planet's atmosphere. The method is based on an analysis of relative wave amplitude determined from the vertical temperature profile, as well as on the proposition of the IGW linear theory, according to which the wave amplitude is limited by the processes of dynamic (shear) instability in the atmosphere. It is supposed that, when the amplitude of the internal wave reaches the shear instability threshold as the wave propagates upward, a dissipation of wave energy occurs such that the IGW amplitude is maintained at the atmospheric instability threshold. The application of the developed method to vertical temperature profiles obtained from radio occultation measurements of the MGS ( Mars Global Surveyor) mission made it possible to identify IGWs in the Martian atmosphere and determine the values of key wave parameters such as intrinsic frequency, amplitudes of the vertical and horizontal disturbances of wind velocity, vertical and horizontal wavelength, intrinsic vertical and horizontal phase (and group) velocities, kinetic, potential, and total energy of IGWs per unit mass, vertical fluxes of wave energy and horizontal momentum. Identified in the Martian atmosphere IGWs, with a vertical wavelength of 4.5-8.2 km, are waves with low intrinsic frequencies close to inertial frequency. Their kinetic energy, as a rule, is greater than potential energy by an order of magnitude. The propagation of these waves causes a significant modulation of the stability of atmospheric stratification that leads to shear instability and the occurrence of thin layers of intermittent turbulence in the Martian atmosphere.

  7. Applying the seismic interferometry method to vertical seismic profile data using tunnel excavation noise as source

    NASA Astrophysics Data System (ADS)

    Jurado, Maria Jose; Teixido, Teresa; Martin, Elena; Segarra, Miguel; Segura, Carlos

    2013-04-01

    In the frame of the research conducted to develop efficient strategies for investigation of rock properties and fluids ahead of tunnel excavations the seismic interferometry method was applied to analyze the data acquired in boreholes instrumented with geophone strings. The results obtained confirmed that seismic interferometry provided an improved resolution of petrophysical properties to identify heterogeneities and geological structures ahead of the excavation. These features are beyond the resolution of other conventional geophysical methods but can be the cause severe problems in the excavation of tunnels. Geophone strings were used to record different types of seismic noise generated at the tunnel head during excavation with a tunnelling machine and also during the placement of the rings covering the tunnel excavation. In this study we show how tunnel construction activities have been characterized as source of seismic signal and used in our research as the seismic source signal for generating a 3D reflection seismic survey. The data was recorded in vertical water filled borehole with a borehole seismic string at a distance of 60 m from the tunnel trace. A reference pilot signal was obtained from seismograms acquired close the tunnel face excavation in order to obtain best signal-to-noise ratio to be used in the interferometry processing (Poletto et al., 2010). The seismic interferometry method (Claerbout 1968) was successfully applied to image the subsurface geological structure using the seismic wave field generated by tunneling (tunnelling machine and construction activities) recorded with geophone strings. This technique was applied simulating virtual shot records related to the number of receivers in the borehole with the seismic transmitted events, and processing the data as a reflection seismic survey. The pseudo reflective wave field was obtained by cross-correlation of the transmitted wave data. We applied the relationship between the transmission

  8. Development of a computer technique for the prediction of transport aircraft flight profile sonic boom signatures. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Coen, Peter G.

    1991-01-01

    A new computer technique for the analysis of transport aircraft sonic boom signature characteristics was developed. This new technique, based on linear theory methods, combines the previously separate equivalent area and F function development with a signature propagation method using a single geometry description. The new technique was implemented in a stand-alone computer program and was incorporated into an aircraft performance analysis program. Through these implementations, both configuration designers and performance analysts are given new capabilities to rapidly analyze an aircraft's sonic boom characteristics throughout the flight envelope.

  9. Vertical profiles of soil water content as influenced by environmental factors in a small catchment on the hilly-gully Loess Plateau.

    PubMed

    Wang, Bing; Wen, Fenxiang; Wu, Jiangtao; Wang, Xiaojun; Hu, Yani

    2014-01-01

    Characterization of soil water content (SWC) profiles at catchment scale has profound implications for understanding hydrological processes of the terrestrial water cycle, thereby contributing to sustainable water management and ecological restoration in arid and semi-arid regions. This study described the vertical profiles of SWC at the small catchment scale on the hilly and gully Loess Plateau in Northeast China, and evaluated the influences of selected environmental factors (land-use type, topography and landform) on average SWC within 300 cm depth. Soils were sampled from 101 points across a small catchment before and after the rainy season. Cluster analysis showed that soil profiles with high-level SWC in a stable trend (from top to bottom) were most commonly present in the catchment, especially in the gully related to terrace. Woodland soil profiles had low-level SWC with vertical variations in a descending or stable trend. Most abandoned farmland and grassland soil profiles had medium-level SWC with vertical variations in varying trends. No soil profiles had low-level SWC with vertical variations in an ascending trend. Multi-regression analysis showed that average SWC was significantly affected by land-use type in different soil layers (0-20, 20-160, and 160-300 cm), generally in descending order of terrace, abandoned farmland, grassland, and woodland. There was a significant negative correlation between average SWC and gradient along the whole profile (P<0.05). Landform significantly affected SWC in the surface soil layer (0-20 cm) before the rainy season but throughout the whole profile after the rainy season, with lower levels on the ridge than in the gully. Altitude only strongly affected SWC after the rainy season. The results indicated that land-use type, gradient, landform, and altitude should be considered in spatial SWC estimation and sustainable water management in these small catchments on the Loess Plateau as well as in other complex terrains

  10. The Potential of The Synergy of Sunphotometer and Lidar Data to Validate Vertical Profiles of The Aerosol Mass Concentration Estimated by An Air Quality Model

    NASA Astrophysics Data System (ADS)

    Siomos, N.; Filioglou, M.; Poupkou, A.; Liora, N.; Dimopoulos, S.; Melas, D.; Chaikovsky, A.; Balis, D. S.

    2016-06-01

    Vertical profiles of the aerosol mass concentration derived by the Lidar/Radiometer Inversion Code (LIRIC), that uses combined sunphotometer and lidar data, were used in order to validate the aerosol mass concentration profiles estimated by the air quality model CAMx. Lidar and CIMEL measurements performed at the Laboratory of Atmospheric Physics of the Aristotle University of Thessaloniki, Greece (40.5N, 22.9E) from the period 2013-2014 were used in this study.

  11. Analysis of P and S wave vertical seismic profile data from the Salton Sea Scientific Drilling Project

    SciTech Connect

    Daley, T.M.; McEvilly, T.V.; Majer, E.L.

    1988-11-10

    As part of the Salton Sea Scientific Drilling Project at California State well 2--14, vertical seismic profile (VSP) data were collected from P and S wave sources at two distances from the well. Use of a three-component geophone, along with rotation of the recorded data traces into a wave front-based coordinate system, allows analysis of many aspects of seismic wave propagation properties around the well. Standard VSP analysis techniques were used to measure interval P and S wave velocities and to identify reflecting horizons both within and below the survey interval (from 455 to 1735 m). A reflection from below the survey interval, seen with both P and S sources, seems to be associated with a fractured reservoir near 2100 m. Indications of fracturing were observed, including vertical scattering of P waves from a zone near 915 m. Orthogonally polarized shear waves were generated at each offset to study anisotropy by travel time measurement and particle motion analysis of the shear wave arrivals. Three component particle motion analysis of shear wave arrivals was found to be effective for characterizing the subtleties in the S wave splitting throughout the various zones in the well. The SH/sub t/ source (horizontal and transverse to the well) produced complicated, elliptical particle motion while the SV source (in-line with the well) produced linear particle motion. The difference in linearity of particle motion from orthogonally polarized shear wave sources was unexpected and may be related to regional tectonics. Anomalous zones may be related to transition depths in the Salton Sea geothermal field. Travel time difference between SV and SH waves, while clearly observable, indicates only about 1% average anisotropy.

  12. A new method to measure Bowen ratios using high-resolution vertical dry and wet bulb temperature profiles

    NASA Astrophysics Data System (ADS)

    Euser, T.; Luxemburg, W. M. J.; Everson, C. S.; Mengistu, M. G.; Clulow, A. D.; Bastiaanssen, W. G. M.

    2014-06-01

    The Bowen ratio surface energy balance method is a relatively simple method to determine the latent heat flux and the actual land surface evaporation. The Bowen ratio method is based on the measurement of air temperature and vapour pressure gradients. If these measurements are performed at only two heights, correctness of data becomes critical. In this paper we present the concept of a new measurement method to estimate the Bowen ratio based on vertical dry and wet bulb temperature profiles with high spatial resolution. A short field experiment with distributed temperature sensing (DTS) in a fibre optic cable with 13 measurement points in the vertical was undertaken. A dry and a wetted section of a fibre optic cable were suspended on a 6 m high tower installed over a sugar beet trial plot near Pietermaritzburg (South Africa). Using the DTS cable as a psychrometer, a near continuous observation of vapour pressure and air temperature at 0.20 m intervals was established. These data allowed the computation of the Bowen ratio with a high spatial and temporal precision. The daytime latent and sensible heat fluxes were estimated by combining the Bowen ratio values from the DTS-based system with independent measurements of net radiation and soil heat flux. The sensible heat flux, which is the relevant term to evaluate, derived from the DTS-based Bowen ratio (BR-DTS) was compared with that derived from co-located eddy covariance (R2 = 0.91), surface layer scintillometer (R2 = 0.81) and surface renewal (R2 = 0.86) systems. By using multiple measurement points instead of two, more confidence in the derived Bowen ratio values is obtained.

  13. Empirical conversion of the vertical profile of reflectivity from Ku-band to S-band frequency

    NASA Astrophysics Data System (ADS)

    Cao, Qing; Hong, Yang; Qi, Youcun; Wen, Yixin; Zhang, Jian; Gourley, Jonathan J.; Liao, Liang

    2013-02-01

    ABSTRACT This paper presents an empirical method for converting reflectivity from Ku-band (13.8 GHz) to S-band (2.8 GHz) for several hydrometeor species, which facilitates the incorporation of Tropical Rainfall Measuring Mission (TRMM) Precipitation Radar (PR) measurements into quantitative precipitation estimation (QPE) products from the U.S. Next-Generation Radar (NEXRAD). The development of empirical dual-frequency relations is based on theoretical simulations, which have assumed appropriate scattering and microphysical models for liquid and solid hydrometeors (raindrops, snow, and ice/hail). Particle phase, shape, orientation, and density (especially for snow particles) have been considered in applying the T-matrix method to compute the scattering amplitudes. Gamma particle size distribution (PSD) is utilized to model the microphysical properties in the ice region, melting layer, and raining region of precipitating clouds. The variability of PSD parameters is considered to study the characteristics of dual-frequency reflectivity, especially the variations in radar dual-frequency ratio (DFR). The empirical relations between DFR and Ku-band reflectivity have been derived for particles in different regions within the vertical structure of precipitating clouds. The reflectivity conversion using the proposed empirical relations has been tested using real data collected by TRMM-PR and a prototype polarimetric WSR-88D (Weather Surveillance Radar 88 Doppler) radar, KOUN. The processing and analysis of collocated data demonstrate the validity of the proposed empirical relations and substantiate their practical significance for reflectivity conversion, which is essential to the TRMM-based vertical profile of reflectivity correction approach in improving NEXRAD-based QPE.

  14. Seven years of IASI ozone retrievals from FORLI: validation with independent total column and vertical profile measurements

    NASA Astrophysics Data System (ADS)

    Boynard, Anne; Hurtmans, Daniel; Koukouli, Mariliza E.; Goutail, Florence; Bureau, Jérôme; Safieddine, Sarah; Lerot, Christophe; Hadji-Lazaro, Juliette; Wespes, Catherine; Pommereau, Jean-Pierre; Pazmino, Andrea; Zyrichidou, Irene; Balis, Dimitris; Barbe, Alain; Mikhailenko, Semen N.; Loyola, Diego; Valks, Pieter; Van Roozendael, Michel; Coheur, Pierre-François; Clerbaux, Cathy

    2016-09-01

    This paper presents an extensive intercomparison and validation for the ozone (O3) product measured by the two Infrared Atmospheric Sounding Interferometers (IASIs) launched on board the MetOp-A and MetOp-B satellites in 2006 and in 2012 respectively. IASI O3 total columns and vertical profiles obtained from Fast Optimal Retrievals on Layers for IASI (FORLI) v20140922 software (running up until recently) are validated against independent observations during the period 2008-2014 on a global scale. On average for the period 2013-2014, IASI-A and IASI-B total ozone columns (TOCs) retrieved using FORLI are consistent, with IASI-B providing slightly lower values with a global difference of only 0.2 ± 0.8 %. The comparison between IASI-A and IASI-B O3 vertical profiles shows differences within ± 2 % over the entire altitude range. Global validation results for 7 years of IASI TOCs from FORLI against the Global Ozone Monitoring Experiment-2 (GOME-2) launched on board MetOp-A and Brewer-Dobson data show that, on average, IASI overestimates the ultraviolet (UV) data by 5-6 % with the largest differences found in the southern high latitudes. The comparison with UV-visible SAOZ (Système d'Analyse par Observation Zénithale) measurements shows a mean bias between IASI and SAOZ TOCs of 2-4 % in the midlatitudes and tropics and 7 % at the polar circle. Part of the discrepancies found at high latitudes can be attributed to the limited information content in the observations due to low brightness temperatures. The comparison with ozonesonde vertical profiles (limited to 30 km) shows that on average IASI with FORLI processing underestimates O3 by ˜ 5-15 % in the troposphere while it overestimates O3 by ˜ 10-40 % in the stratosphere, depending on the latitude. The largest relative differences are found in the tropical tropopause region; this can be explained by the low O3 amounts leading to large relative errors. In this study, we also evaluate an updated version of FORLI-O3

  15. Evolution of Metallic Trace Elements in Contaminated River Sediments: Geochemical Variation Along River Linear and Vertical Profile

    NASA Astrophysics Data System (ADS)

    Kanbar, Hussein; Montarges-Pelletier, Emmanuelle; Mansuy-Huault, Laurence; Losson, Benoit; Manceau, Luc; Bauer, Allan; Bihannic, Isabelle; Gley, Renaud; El Samrani, Antoine; Kobaissi, Ahmad; Kazpard, Veronique; Villieras, Frédéric

    2015-04-01

    Metal pollution in riverine systems poses a serious threat that jeopardizes water and sediment quality, and hence river dwelling biota. Since those metallic pollutants can be transported for long distances via river flow, river management has become a great necessity, especially in times where industrial activities and global climate change are causing metal release and spreading (by flooding events). These changes are able to modify river hydrodynamics, and as a consequence natural physico-chemical status of different aquatic system compartments, which in turn alter metal mobility, availability and speciation. Vertical profiles of sediments hold the archive of what has been deposited for several tenths of years, thus they are used as a tool to study what had been deposited in rivers beds. The studied area lies in the Orne river, northeastern France. This river had been strongly modified physically and affected by steelmaking industrial activities that had boosted in the middle of the last century. This study focuses on several sites along the linear of the Orne river, as well as vertical profiles of sediments. Sediment cores were collected at sites where sedimentation is favoured, and in particular upstream two dams, built in the second half of the XXth century for industrial purposes. Sediment cores were sliced into 2-5cm layers, according to suitability, and analysed for physical and physico-chemical properties, elemental content and mineralogy. Data of the vertical profile in a sediment core is important to show the evolution of sediments as a function of depth, and hence age, in terms of nature, size and constituents. The physical properties include particle size distribution (PSD) and water content. In addition, the physico-chemical properties, such as pH and oxido-reduction potential (ORP) of interstitial water from undisturbed cores were also detected. Total elemental content of sediment and available ones of extracted interstitial waters was detected using

  16. Dynamic links between shape of the eddy viscosity profile and the vertical structure of tidal current amplitude in bays and estuaries

    NASA Astrophysics Data System (ADS)

    Chen, Wei; de Swart, Huib E.

    2016-03-01

    Several field studies in bays and estuaries have revealed pronounced subsurface maxima in the vertical profiles of the current amplitude of the principal tidal harmonic, or of its vertical shear, over the water column. To gain fundamental understanding about these phenomena, a semi-analytical model is designed and analysed, with focus on the sensitivity of the vertical structure of the tidal current amplitude to formulations of the vertical shape of the eddy viscosity. The new analytical solutions for the tidal current amplitude are used to explore their dependence on the degree of surface mixing, the vertical shape of eddy viscosity in the upper part of the water column and the density stratification. Sources of surface mixing are wind and whitecapping. Results show three types of current amplitude profiles of tidal harmonics, characterised by monotonically decreasing shear towards the surface, "surface jumps" (vertical shear of tidal current amplitude has a subsurface maximum) and "subsurface jets" (maximum tidal current amplitude below the surface), respectively. The "surface jumps" and "subsurface jets" both occur for low turbulence near the surface, whilst additionally the surface jumps only occur if the eddy viscosity in the upper part of the water column decreases faster than linearly to the surface. Furthermore, "surface jumps" take place for low density stratification, while and "subsurface jets" occur for high density stratification. The physics causing the presence of surface jumps and subsurface jets is also discussed.

  17. Improving the Automatic Inversion of Digital ISIS-2 Ionogram Reflection Traces into Topside Vertical Electron-Density Profiles

    NASA Technical Reports Server (NTRS)

    Benson, R. F.; Truhlik, V.; Huang, X.; Wang, Y.; Bilitza, D.

    2011-01-01

    The topside-sounders on the four satellites of the International Satellites for Ionospheric Studies (ISIS) program were designed as analog systems. The resulting ionograms were displayed on 35-mm film for analysis by visual inspection. Each of these satellites, launched between 1962 and 1971, produced data for 10 to 20 years. A number of the original telemetry tapes from this large data set have been converted directly into digital records. Software, known as the TOPside Ionogram Scalar with True-height (TOPIST) algorithm has been produced that enables the automatic inversion of ISIS-2 ionogram reflection traces into topside vertical electron-density profiles Ne(h). More than million digital Alouette/ISIS topside ionograms have been produced and over 300,000 are from ISIS 2. Many of these ISIS-2 ionograms correspond to a passive mode of operation for the detection of natural radio emissions and thus do not contain ionospheric reflection traces. TOPIST, however, is not able to produce Ne(h) profiles from all of the ISIS-2 ionograms with reflection traces because some of them did not contain frequency information. This information was missing due to difficulties encountered during the analog-to-digital conversion process in the detection of the ionogram frame-sync pulse and/or the frequency markers. Of the many digital topside ionograms that TOPIST was able to process, over 200 were found where direct comparisons could be made with Ne(h) profiles that were produced by manual scaling in the early days of the ISIS program. While many of these comparisons indicated excellent agreement (<10% average difference over the entire profile) there were also many cases with large differences (more than a factor of two). Here we will report on two approaches to improve the automatic inversion process: (1) improve the quality of the digital ionogram database by remedying the missing frequency-information problem when possible, and (2) using the above-mentioned comparisons as

  18. [Analysis of the Influence of Temperature on the Retrieval of Ozone Vertical Profiles Using the Thermal Infrared CrIS Sounder].

    PubMed

    Ma, Peng-fei; Chen, Liang-fu; Zou, Ming-min; Zhang, Ying; Tao, Ming-hui; Wang, Zi-leng; Su, Lin

    2015-12-01

    Ozone is a particularly critical trace gas in the Earth's atmosphere, since this molecule plays a key role in the photochemical reactions and climate change. The TIR measurements can capture the variability of ozone and are weakly sensitive to the lowermost tropospheric ozone content but can provide accurate measurements of tropospheric ozone and higher vertical resolution ozone profiles, with the additional advantage that measurements are also possible during the night. Because of the influence of atmospheric temperature, the ozone profile retrieval accuracy is severely limited. This paper analyze and discuss the ozone absorption spectra and weighting function sensitivity of temperature and its influence on ozone profile retrieval in detail. First, we simulate the change of atmospheric transmittance and radiance by importing 1 K temperature uncertainty, using line-by-line radiative transfer mode under 6 different atmosphere modes. The results show that the transmittance change ratio for 1 K temperature variation was consistent with the transmittance change ratio for 5%-6% change of ozone density variation in all layers of the profile. Then, we calculate the change of weighting function by a temperature error of 1 K, using the Community Radiative Transfer Model (CRTM) for the Cross-track Infrared Sounder (CrIS) on the Suomi National Polar-orbiting Partnership (Suomi NPP) satellite and calculate the corresponding change of retrieval result. The results demonstrate that CrIS is sensitive to Ozone in the middle to upper stratosphere, with the peak vertical sensitivity between 10-100 hPa and the change of weighting function for 1 K temperature variation was consistent with 6% change in the ozone profile. Finally, the paper retrieves ozone profiles from the CrIS radiances with a nonlinear Newton iteration method and use the eigenvector regression algorithm to construct the a priori state. In order to resolve the problem of temperature uncertainty and get high accuracy

  19. Source apportionment of PAHs and n-alkanes in respirable particles in Tehran, Iran by wind sector and vertical profile.

    PubMed

    Moeinaddini, Mazaher; Esmaili Sari, Abbas; Riyahi bakhtiari, Alireza; Chan, Andrew Yiu-Chung; Taghavi, Seyed Mohammad; Hawker, Darryl; Connell, Des

    2014-06-01

    The vertical concentration profiles and source contributions of polycyclic aromatic hydrocarbons (PAHs) and n-alkanes in respirable particle samples (PM4) collected at 10, 100, 200 and 300-m altitude from the Milad Tower of Tehran, Iran during fall and winter were investigated. The average concentrations of total PAHs and total n-alkanes were 16.7 and 591 ng/m(3), respectively. The positive matrix factorization (PMF) model was applied to the chemical composition and wind data to apportion the contributing sources. The five PAH source factors identified were: 'diesel' (56.3% of total PAHs on average), 'gasoline' (15.5%), 'wood combustion, and incineration' (13%), 'industry' (9.2%), and 'road soil particle' (6.0%). The four n-alkane source factors identified were: 'petrogenic' (65% of total n-alkanes on average), 'mixture of petrogenic and biomass burning' (15%), 'mixture of biogenic and fossil fuel' (11.5%), and 'biogenic' (8.5%). Source contributions by wind sector were also estimated based on the wind sector factor loadings from PMF analysis. Directional dependence of sources was investigated using the conditional probability function (CPF) and directional relative strength (DRS) methods. The calm wind period was found to contribute to 4.4% of total PAHs and 5.0% of total n-alkanes on average. Highest average concentrations of PAHs and n-alkanes were found in the 10 and 100 m samples, reflecting the importance of contributions from local sources. Higher average concentrations in the 300 m samples compared to those in the 200 m samples may indicate contributions from long-range transport. The vertical profiles of source factors indicate the gasoline and road soil particle-associated PAHs, and the mixture from biogenic and fossil fuel source-associated n-alkanes were mostly from local emissions. The smaller average contribution of diesel-associated PAHs in the lower altitude samples also indicates that the restriction of diesel-fueled vehicle use in the central area

  20. Impact of black carbon aerosol over Italian basin valleys: high-resolution measurements along vertical profiles, radiative forcing and heating rate

    NASA Astrophysics Data System (ADS)

    Ferrero, L.; Castelli, M.; Ferrini, B. S.; Moscatelli, M.; Perrone, M. G.; Sangiorgi, G.; D'Angelo, L.; Rovelli, G.; Moroni, B.; Scardazza, F.; Močnik, G.; Bolzacchini, E.; Petitta, M.; Cappelletti, D.

    2014-09-01

    A systematic study of black carbon (BC) vertical profiles measured at high-resolution over three Italian basin valleys (Terni Valley, Po Valley and Passiria Valley) is presented. BC vertical profiles are scarcely available in literature. The campaign lasted 45 days and resulted in 120 measured vertical profiles. Besides the BC mass concentration, measurements along the vertical profiles also included aerosol size distributions in the optical particle counter range, chemical analysis of filter samples and a full set of meteorological parameters. Using the collected experimental data, we performed calculations of aerosol optical properties along the vertical profiles. The results, validated with AERONET data, were used as inputs to a radiative transfer model (libRadtran). The latter allowed an estimation of vertical profiles of the aerosol direct radiative effect, the atmospheric absorption and the heating rate in the lower troposphere. The present measurements revealed some common behaviors over the studied basin valleys. Specifically, at the mixing height, marked concentration drops of both BC (range: from -48.4 ± 5.3 to -69.1 ± 5.5%) and aerosols (range: from -23.9 ± 4.3 to -46.5 ± 7.3%) were found. The measured percentage decrease of BC was higher than that of aerosols: therefore, the BC aerosol fraction decreased upwards. Correspondingly, both the absorption and scattering coefficients decreased strongly across the mixing layer (range: from -47.6 ± 2.5 to -71.3 ± 3.0% and from -23.5 ± 0.8 to -61.2 ± 3.1%, respectively) resulting in a single-scattering albedo increase along height (range: from +4.9 ± 2.2 to +7.4 ± 1.0%). This behavior influenced the vertical distribution of the aerosol direct radiative effect and of the heating rate. In this respect, the highest atmospheric absorption of radiation was predicted below the mixing height (~ 2-3 times larger than above it) resulting in a heating rate characterized by a vertical negative gradient (range

  1. Value of corneal epithelial and Bowman’s layer vertical thickness profiles generated by UHR-OCT for sub-clinical keratoconus diagnosis

    PubMed Central

    Xu, Zhe; Jiang, Jun; Yang, Chun; Huang, Shenghai; Peng, Mei; Li, Weibo; Cui, Lele; Wang, Jianhua; Lu, Fan; Shen, Meixiao

    2016-01-01

    Ultra-high resolution optical coherence tomography (UHR-OCT) can image the corneal epithelium and Bowman’s layer and measurement the thicknesses. The purpose of this study was to validate the diagnostic power of vertical thickness profiles of the corneal epithelium and Bowman’s layer imaged by UHR-OCT in the diagnosis of sub-clinical keratoconus (KC). Each eye of 37 KC patients, asymptomatic fellow eyes of 32 KC patients, and each eye of 81 normal subjects were enrolled. Vertical thickness profiles of the corneal epithelium and Bowman’s layer were measured by UHR-OCT. Diagnostic indices were calculated from vertical thickness profiles of each layer and output values of discriminant functions based on individual indices. Receiver operating characteristic curves were determined, and the accuracy of the diagnostic indices were assessed as the area under the curves (AUC). Among all of the individual indices, the maximum ectasia index for epithelium had the highest ability to discriminate sub-clinical KC from normal corneas (AUC = 0.939). The discriminant function containing maximum ectasia indices of epithelium and Bowman’s layer further increased the AUC value (AUC = 0.970) for sub-clinical KC diagnosis. UHR-OCT-derived thickness indices from the entire vertical thickness profiles of the corneal epithelium and Bowman’s layer can provide valuable diagnostic references to detect sub-clinical KC. PMID:27511620

  2. Modeling direction discrimination thresholds for yaw rotations around an earth-vertical axis for arbitrary motion profiles.

    PubMed

    Soyka, Florian; Giordano, Paolo Robuffo; Barnett-Cowan, Michael; Bülthoff, Heinrich H

    2012-07-01

    Understanding the dynamics of vestibular perception is important, for example, for improving the realism of motion simulation and virtual reality environments or for diagnosing patients suffering from vestibular problems. Previous research has found a dependence of direction discrimination thresholds for rotational motions on the period length (inverse frequency) of a transient (single cycle) sinusoidal acceleration stimulus. However, self-motion is seldom purely sinusoidal, and up to now, no models have been proposed that take into account non-sinusoidal stimuli for rotational motions. In this work, the influence of both the period length and the specific time course of an inertial stimulus is investigated. Thresholds for three acceleration profile shapes (triangular, sinusoidal, and trapezoidal) were measured for three period lengths (0.3, 1.4, and 6.7 s) in ten participants. A two-alternative forced-choice discrimination task was used where participants had to judge if a yaw rotation around an earth-vertical axis was leftward or rightward. The peak velocity of the stimulus was varied, and the threshold was defined as the stimulus yielding 75 % correct answers. In accordance with previous research, thresholds decreased with shortening period length (from ~2 deg/s for 6.7 s to ~0.8 deg/s for 0.3 s). The peak velocity was the determining factor for discrimination: Different profiles with the same period length have similar velocity thresholds. These measurements were used to fit a novel model based on a description of the firing rate of semi-circular canal neurons. In accordance with previous research, the estimates of the model parameters suggest that velocity storage does not influence perceptual thresholds.

  3. Detection of fractures within the Soultz-sous-Forêts EGS geothermal reservoir by processing of Vertical Seismic Profile data

    NASA Astrophysics Data System (ADS)

    Lubrano Lavadera, P.; Marthelot, J. M.; Zillmer, M.; Cornet, F.

    2012-04-01

    The 4 component multi-source/multi-offset VSP (Vertical Seismic Profile) conducted at the Soultz-sous-Forêts EGS (Enhanced Geothermal System) site in 2007 provides records of seismic waves recorded in the fractured granite basement within wells GPK3 and GPK4. Waves generated at 26 surface positions, located at distances between 500m and 5km from the well head in different azimuths, are recorded by 3 component geophones at depths between 5000m and 3000m with a 20m depth interval. The seismic source is a vibrator emitting a 16s long sweep with frequencies varying linearly between 8 and 88 Hz. Two shot locations were simultaneously recorded, one with an upsweep [8 to 88Hz], the other with a downsweep [88 to 8Hz]. Successive correlation with the two sweeps allows retrieving distinct seismograms for each shot from the mixed raw uncorrelated records. Most records show clear downgoing P and S waves. Detecting waves reflected or diffracted by fractures intersecting the wells requires extracting low amplitude upgoing waves from the dominant downgoing wavefield. However, the up to 30° inclination of the well relative to the vertical and the 60 to 90° dips of the fracture zones make the separation of the different waves complex. The wavefield separation of the vertical geophone component is done in the frequency-wavenumber Fourier domain which separates waves according to their apparent velocity across the receiver antenna. Picking of the first arrival times and shifting times allows aligning predominant P wave downgoing wavefield at constant times, or infinite apparent velocity in Fourier domain. Filtering the infinite apparent velocity attenuates all the waves having the same apparent velocity as the first arrivals. A second filtering at the downgoing S waves velocities is then applied, providing two downgoing wavefields, one for the P waves and the other for the S waves. The residuals correspond to the upgoing wavefield. To reduce the reverberations in the upgoing

  4. Results of vertical seismic profiling at Well 46-28, Rye Patch Geothermal Field, Pershing County, Nevada

    SciTech Connect

    Feighner, M.A.; Daley, T.M.; Majer, E.L.

    1998-02-25

    A Vertical Seismic Profile (VSP) was recorded in Rye Patch by LBNL between December 11 and December 13, 1997. Figure 1 shows the location of the Rye Patch Geothermal Field with Well 46-28 located within the marked Rye Patch Anomaly. The VSP in Well 46-28 used a vibroseis source and a single-level, high temperature, hydraulic wall-locking, 3-component seismometer. The vibroseis source was a Mertz P-wave vibrator. The source sweep was 10 Hz to 80 Hz, 10 seconds long, with a 0.2 s cosine taper. The borehole geophone was an SSC model LVHK 6001 using 14 Hz geophones. The recording system was a Geometrics Strataview. Six data channels were recorded: the three geophones, the source pilot, the vibrator reference and the vibrator baseplate accelerometer. The record length was 12,288 samples at a 1 ms sample rate, giving a 2.3 s correlated record length. A 10 Hz low cut filter was used and no high cut filter was used except the anti-alias filter. Results are described.

  5. The dependence of vertical cloud profiles from CloudSat-CALIPSO retrievals on the degree of convective aggregation

    NASA Astrophysics Data System (ADS)

    Holloway, Chris; Stein, Thorwald; Tobin, Isabelle; Bony, Sandrine

    2015-04-01

    Previous work (Tobin et al. 2012, Tobin et al. 2013) has found that the degree of aggregation of convection in satellite observations, as measured by the Simple Convective Aggregation Index (SCAI), is associated with systematic differences in mean environmental moisture and outgoing longwave radiation for a given large-scale forcing. This suggests that climate models need to simulate the degree of organization of convection, and not just the mean precipitation and convective fluxes, in order to fully represent interactions between convection and larger scales. In this study, we use five years of CloudSat-CALIPSO cloud profiles alongside TRMM rainfall, geostationary IR data, ERA- Interim water vapor, and other observations to investigate the relationship between vertical cloud distributions and the SCAI aggregation index. We find that there is a significant decrease in anvil cloud (and in cloudiness as a whole) and increase in clear sky and low cloud (including cumulus) as aggregation increases (for a given precipitation rate). The changes in anvil and shallow cumulus are proportional to the changes in total cold cloud area (CCA), meaning that anvil per CCA and cumulus as a fraction of non-cold cloud area (1-CCA) do not change much even as CCA decreases with increased aggregation; in contrast, the change in clear sky occurs in both an absolute sense and as a fraction of non-cold cloud area (1-CCA).

  6. Experimental observation of the influence of furnace temperature profile on convection and segregation in the vertical Bridgman crystal growth technique

    NASA Technical Reports Server (NTRS)

    Neugebauer, G. T.; Wilcox, William R.

    1992-01-01

    Azulene-doped naphthalene was directionally solidified during the vertical Bridgman-Stockbarger technique. Doping homogeneity and convection were determined as a function of the temperature profile in the furnace and the freezing rate. Convection velocities were two orders of magnitude lower when the temperature increased with height. Rarely was the convection pattern axisymmetric, even though the temperature varied less than 0.1 K around the circumference of the growth ampoule. Correspondingly the cross sectional variation in azulene concentration tended to be asymmetric, especially when the temperature increased with height. This cross sectional variation changed dramatically along the ingot, reflecting changes in convection presumably due to the decreasing height of the melt. Although there was large scatter and irreproducibility in the cross sectional variation in doping, this variation tended to be least when the growth rate was low and the convection was vigorous. It is expected that compositional variations would also be small at high growth rates with weak convection and flat interfaces, although this was not investigated in the present experiments. Neither rotation of the ampoule nor deliberate introduction of thermal asymmetries during solidification had a significant influence on cross sectional variations in doping. It is predicted that slow directional solidification under microgravity conditions could produce greater inhomogeneities than on Earth. Combined use of microgravity and magnetic fields would be required to achieve homogeneity when it is necessary to freeze slowly in order to avoid constitutional supercooling.

  7. Vertical microphysical profiles of convective clouds as a tool for obtaining aerosol cloud-mediated climate forcings

    SciTech Connect

    Rosenfeld, Daniel

    2015-12-23

    Quantifying the aerosol/cloud-mediated radiative effect at a global scale requires simultaneous satellite retrievals of cloud condensation nuclei (CCN) concentrations and cloud base updraft velocities (Wb). Hitherto, the inability to do so has been a major cause of high uncertainty regarding anthropogenic aerosol/cloud-mediated radiative forcing. This can be addressed by the emerging capability of estimating CCN and Wb of boundary layer convective clouds from an operational polar orbiting weather satellite. Our methodology uses such clouds as an effective analog for CCN chambers. The cloud base supersaturation (S) is determined by Wb and the satellite-retrieved cloud base drop concentrations (Ndb), which is the same as CCN(S). Developing and validating this methodology was possible thanks to the ASR/ARM measurements of CCN and vertical updraft profiles. Validation against ground-based CCN instruments at the ARM sites in Oklahoma, Manaus, and onboard a ship in the northeast Pacific showed a retrieval accuracy of ±25% to ±30% for individual satellite overpasses. The methodology is presently limited to boundary layer not raining convective clouds of at least 1 km depth that are not obscured by upper layer clouds, including semitransparent cirrus. The limitation for small solar backscattering angles of <25º restricts the satellite coverage to ~25% of the world area in a single day. This methodology will likely allow overcoming the challenge of quantifying the aerosol indirect effect and facilitate a substantial reduction of the uncertainty in anthropogenic climate forcing.

  8. The application of vertical seismic profiling and cross-hole tomographic imaging for fracture characterization at Yucca Mountain

    SciTech Connect

    Majer, E.L.; Peterson, J.E.; Tura, M.A.; McEvilly, T.V.

    1990-01-01

    In order to obtain the necessary characterization for the storage of nuclear waste, much higher resolution of the features likely to affect the transport of radionuclides will be required than is normally achieved in conventional surface seismic reflection used in the exploration and characterization of petroleum and geothermal resources. Because fractures represent a significant mechanical anomaly seismic methods using are being investigated as a means to image and characterize the subsurface. Because of inherent limitations in applying the seismic methods solely from the surface, state-of-the-art borehole methods are being investigated to provide high resolution definition within the repository block. Therefore, Vertical Seismic Profiling (VSP) and cross-hole methods are being developed to obtain maximum resolution of the features that will possible affect the transport of fluids. Presented here will be the methods being developed, the strategy being pursued, and the rational for using VSP and crosshole methods at Yucca Mountain. The approach is intended to be an integrated method involving improvements in data acquisition, processing, and interpretation as well as improvements in the fundamental understanding of seismic wave propagation in fractured rock. 33 refs., 4 figs.

  9. Indoor air quality investigation on commercial aircraft.

    PubMed

    Lee, S C; Poon, C S; Li, X D; Luk, F

    1999-09-01

    Sixteen flights had been investigated for indoor air quality (IAQ) on Cathay Pacific aircraft from June 1996 to August 1997. In general, the air quality on Cathay Pacific aircraft was within relevant air quality standards because the average age of aircraft was less than 2 years. Carbon dioxide (CO2) levels on all flights measured were below the Federal Aviation Administration (FAA) standard (30,000 ppm). The CO2 level was substantially higher during boarding and de-boarding than cruise due to low fresh air supply. Humidity on the aircraft was low, especially for long-haul flights. Minimum humidity during cruise was below the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) minimum humidity standard (20%). The average temperature was within a comfortable temperature range of 23 +/- 2 degrees C. The vertical temperature profile on aircraft was uniform and below the International Standard Organization (ISO) standard. Carbon monoxide levels were below the FAA standard (50 ppm). Trace amount of ozone detected ranged from undetectable to 90 ppb, which was below the FAA standard. Particulate level was low for most non-smoking flights, but peaks were observed during boarding and de-boarding. The average particulate level in smoking flights (138 micrograms/m3) was higher than non-smoking flights (7.6 micrograms/m3). The impact on IAQ by switching from low-mode to high-mode ventilation showed a reduction in CO2 levels, temperature, and relative humidity.

  10. Vertical distribution of heavy metals in soil profile in a seasonally waterlogging agriculture field in Eastern Ganges Basin.

    PubMed

    Rajmohan, N; Prathapar, S A; Jayaprakash, M; Nagarajan, R

    2014-09-01

    The accumulation of heavy metals in soil and water is a serious concern due to their persistence and toxicity. This study investigated the vertical distribution of heavy metals, possible sources and their relation with soil texture in a soil profile from seasonally waterlogged agriculture fields of Eastern Ganges basin. Fifteen samples were collected at ~0.90-m interval during drilling of 13.11 mbgl and analysed for physical parameters (moisture content and grain size parameters: sand, silt, clay ratio) and heavy metals (Fe, Mn, Cr, Cu, Pb, Zn, Co, Ni and Cd). The average metal content was in the decreasing order of Fe > Mn > Cr > Zn > Ni > Cu > Co > Pb > Cd. Vertical distribution of Fe, Mn, Zn and Ni shows more or less similar trends, and clay zone records high concentration of heavy metals. The enrichment of heavy metals in clay zone with alkaline pH strongly implies that the heavy metal distributions in the study site are effectively regulated by soil texture and reductive dissolution of Fe and Mn oxy-hydroxides. Correlation coefficient analysis indicates that most of the metals correlate with Fe, Mn and soil texture (clay and silt). Soil quality assessment was carried out using geoaccumulation index (I(geo)), enrichment factor (EF) and contamination factor (CF). The enrichment factor values were ranged between 0.66 (Mn) and 2.34 (Co) for the studied metals, and the contamination factor values varied between 0.79 (Mn) and 2.55 (Co). Results suggest that the elements such as Cu and Co are categorized as moderate to moderately severe contamination, which are further confirmed by I(geo) values (0.69 for Cu and 0.78 for Co). The concentration of Ni exceeded the effects-range median values, and the biological adverse effect of this metal is 87%. The average concentration of heavy metals was compared with published data such as concentration of heavy metals in Ganga River sediments, Ganga Delta sediments and upper continental crust (UCC

  11. Vertical distribution of heavy metals in soil profile in a seasonally waterlogging agriculture field in Eastern Ganges Basin.

    PubMed

    Rajmohan, N; Prathapar, S A; Jayaprakash, M; Nagarajan, R

    2014-09-01

    The accumulation of heavy metals in soil and water is a serious concern due to their persistence and toxicity. This study investigated the vertical distribution of heavy metals, possible sources and their relation with soil texture in a soil profile from seasonally waterlogged agriculture fields of Eastern Ganges basin. Fifteen samples were collected at ~0.90-m interval during drilling of 13.11 mbgl and analysed for physical parameters (moisture content and grain size parameters: sand, silt, clay ratio) and heavy metals (Fe, Mn, Cr, Cu, Pb, Zn, Co, Ni and Cd). The average metal content was in the decreasing order of Fe > Mn > Cr > Zn > Ni > Cu > Co > Pb > Cd. Vertical distribution of Fe, Mn, Zn and Ni shows more or less similar trends, and clay zone records high concentration of heavy metals. The enrichment of heavy metals in clay zone with alkaline pH strongly implies that the heavy metal distributions in the study site are effectively regulated by soil texture and reductive dissolution of Fe and Mn oxy-hydroxides. Correlation coefficient analysis indicates that most of the metals correlate with Fe, Mn and soil texture (clay and silt). Soil quality assessment was carried out using geoaccumulation index (I(geo)), enrichment factor (EF) and contamination factor (CF). The enrichment factor values were ranged between 0.66 (Mn) and 2.34 (Co) for the studied metals, and the contamination factor values varied between 0.79 (Mn) and 2.55 (Co). Results suggest that the elements such as Cu and Co are categorized as moderate to moderately severe contamination, which are further confirmed by I(geo) values (0.69 for Cu and 0.78 for Co). The concentration of Ni exceeded the effects-range median values, and the biological adverse effect of this metal is 87%. The average concentration of heavy metals was compared with published data such as concentration of heavy metals in Ganga River sediments, Ganga Delta sediments and upper continental crust (UCC

  12. Hypersonic aircraft design

    NASA Technical Reports Server (NTRS)

    Alkamhawi, Hani; Greiner, Tom; Fuerst, Gerry; Luich, Shawn; Stonebraker, Bob; Wray, Todd

    1990-01-01

    A hypersonic aircraft is designed which uses scramjets to accelerate from Mach 6 to Mach 10 and sustain that speed for two minutes. Different propulsion systems were considered and it was decided that the aircraft would use one full scale turbofan-ramjet. Two solid rocket boosters were added to save fuel and help the aircraft pass through the transonic region. After considering aerodynamics, aircraft design, stability and control, cooling systems, mission profile, and landing systems, a conventional aircraft configuration was chosen over that of a waverider. The conventional design was chosen due to its landing characteristics and the relative expense compared to the waverider. Fuel requirements and the integration of the engine systems and their inlets are also taken into consideration in the final design. A hypersonic aircraft was designed which uses scramjets to accelerate from Mach 6 to Mach 10 and sustain that speed for two minutes. Different propulsion systems were considered and a full scale turbofan-ramjet was chosen. Two solid rocket boosters were added to save fuel and help the aircraft pass through the transonic reqion. After the aerodynamics, aircraft design, stability and control, cooling systems, mission profile, landing systems, and their physical interactions were considered, a conventional aircraft configuration was chosen over that of a waverider. The conventional design was chosen due to its landing characteristics and the relative expense compared to the waverider. Fuel requirements and the integration of the engine systems and their inlets were also considered in the designing process.

  13. Using a fibre-optic cable as Distributed Acoustic Sensor for Vertical Seismic Profiling - Overview of various field tests

    NASA Astrophysics Data System (ADS)

    Götz, Julia; Lüth, Stefan; Henninges, Jan; Reinsch, Thomas

    2015-04-01

    Fibre-optic Distributed Acoustic Sensing (DAS) or Distributed Vibration Sensing (DVS) is a technology, where an optical fibre cable is used as a sensor for acoustic signals. An ambient seismic wavefield, which is coupled by friction or pressure to the optical fibre, induces dynamic strain changes along the cable. The DAS/DVS technology offers the possibility to record an optoelectronic signal which is linearly related to the time dependent local strain. The DAS/DVS technology is based on the established technique of phase-sensitive optical time-domain reflectometry (phi-OTDR). Coherent laser pulses are launched into the fibre to monitor changes in the resulting elastic Rayleigh backscatter with time. Dynamic strain changes lead to small displacements of the scattering elements (non-uniformities within the glass structure of the optical fibre), and therefore to variations of the relative phases of the backscattered photons. The fibre behaves as a series of interferometers whose output is sensitive to small changes of the strain at any point along its length. To record the ground motion not only in space but also in time, snapshots of the wavefield are created by repeatedly firing laser pulses into the fibre at sampling frequencies much higher than seismic frequencies. DAS/DVS is used e.g. for continuous monitoring of pipelines, roads or borders and for production monitoring from within the wellbore. Within the last years, the DAS/DVS technology was further developed to record seismic data. We focus on the recording of Vertical Seismic Profiling (VSP) data with DAS/DVS and present an overview of various field tests published between 2011 and 2014. Here, especially CO2 storage pilot sites provided the opportunity to test this new technology for geophysical reservoir monitoring. DAS/DVS-VSP time-lapse measurements have been published for the Quest CO2 storage site in Canada. The DAS/DVS technology was also tested at the CO2 storage sites in Rousse (France), Citronelle

  14. Methane at Ascension Island, southern tropical Atlantic Ocean: continuous ground measurement and vertical profiling above the Trade-Wind Inversion

    NASA Astrophysics Data System (ADS)

    Lowry, David; Brownlow, Rebecca; Fisher, Rebecca; Nisbet, Euan; Lanoisellé, Mathias; France, James; Thomas, Rick; Mackenzie, Rob; Richardson, Tom; Greatwood, Colin; Freer, Jim; Cain, Michelle; Warwick, Nicola; Pyle, John

    2015-04-01

    δ13CCH4. The marine boundary layer at the surface has CH4 mixing ratios below 1800ppb. In the mixing layer of the TWI, values increase, and above 2000m, methane is above 1820ppb. Back trajectory analysis shows that these inputs are from African savanna and wetland emissions. After vertical mixing events the difference across the TWI reduces to less than 10ppb. The experiment has demonstrated the feasibility of UAV work to observe methane at Ascension. In effect, Ascension becomes a 'virtual mountain observatory' - measurements here can both use the Trade Winds to monitor the wide South Atlantic and Southern Ocean, and also the air above the TWI to assess inputs from tropical Africa and S. America. Comparison of continuous ground measurements, vertical UAV profiles and data from the Ascension TCCON site, potentially allows observation of a complete atmospheric profile. Acknowledgement This work is supported by the Natural Environment Research Council Grant NE/K005979/1

  15. Atmospheric dust charging, vertical profiles and optical properties measured in the Arabian Peninsula during the DREAME campaign

    NASA Astrophysics Data System (ADS)

    Ulanowski, Z.; Sabbah, I.; Harrison, R. G.; Nicoll, K. A.; Hirst, E.; Kaye, P. H.; Al-Abbadi, N.; Rogers, G.

    2010-05-01

    Polarimetric observations of atmospheric Saharan dust over the Canary Islands have provided strong evidence for the presence of vertically aligned particles. The alignment was thought to be due to the electric field present because of dust charging. It was concluded that the charging and consequent partial alignment could be a common feature of atmospheric mineral dust layers, influencing the optical properties of dust layers and possibly also dust transport (Atmos. Chem. Phys. 7, 6161, 2007). We show preliminary results from the DREAME campaign, aimed at investigating these phenomena. DREAME used simultaneous and collocated measurements from specially developed aerosol radiosondes, and ground-based sun photometers and electric field meters. The radiosondes provided vertical profiles of dust size distribution and electric charge density, in addition to standard meteorological parameters (Ulanowski et al. EGU 2010, AS3.16). The electric field was measured in Kuwait between late April and November 2009, and at Solar Village (Riyadh, Saudi Arabia) between May and June 2009. The measurements were supplemented by satellite retrievals of aerosol properties. Similar measurements but without electric field meters were carried out on Cape Verde Islands in August 2009 (Nicoll et al. EGU 2010, AS4.7). The electric field measured on the ground in Kuwait showed strong variability, particularly in the presence of atmospheric dust, when polarity reversals from the normal positive potential gradient (PG) clear-sky pattern were frequently observed. In the absence of clouds the negative PG excursions were often down to -800 V/m and reached -1300 V/m. The PG was strongly correlated with the aerosol optical thickness (AOT) from the sun photometer: the correlation coefficient was about -0.51 at visible and near infra-red wavelengths and a few percent less in the UV. Slightly lower correlation was present for satellite AOT: -0.4 for MODIS AOT at 550 nm, and -0.3 for OMI AOT at 483.5 nm

  16. Surface observations of aerosols and vertical ozone profiling: Influence from the Indo Gangetic Plain, biomass burning and LRT

    NASA Astrophysics Data System (ADS)

    Naja, M. K.; Kotamarthi, V. R.; Singh, N.; Phani, D. V.; Dumka, U. C.; Kumar, R.; Ojha, N.; Bhardhwaj, P.; Lal, S.

    2013-12-01

    South Asia is the home to one of the most populated and polluted region (The Indo-Gangetic Plain, IGP) of the world and variety of anthropogenic and biogenic emission sources are exiting in the same region. Despite of the poor understanding of the physical, chemical, and dynamical processes in the lower atmosphere over this region, there are very limited ground based observations in South Asia. In view of this, an observational facility was setup at ARIES, Nainital (29.4N, 79.5E; 1950 m) in the central Himalayas and at two sites in the IGP region for the surface based trace gases and aerosols observations as well as balloon-borne ozone observations. Further, First Atmospheric Radiation Measurement (ARM) Mobile Facility (AMF1), DOE, was setup at ARIES during a GVAX campaign (June 2011-March 2012) and extensive observations of vertical profiling was also carried out using balloons, doppler Lidar, microwave radiometer, wind profiler and ceilometers. Observations of trace gases and aerosols show a clear enhancement during pre-monsoon and a secondary peak during post-monsoon period. The average scattering Angstrom exponent suggests dominance of relatively larger size particles and single scattering albedo indicates more scattering or less absorbing aerosols in this region. Events of the long-range transport are seen, when concentrations of bigger particle are observed to be higher. Apart from LRT, events of downward transport of ozone rich but drier air-masses are also observed. Extensive in-situ observations of ozone, CO, BC, aerosol absorption, scattering and number-concentration, along with back-air trajectories and MODIS fire-counts have been used to demonstrate evidences of the influence of biomass burning over this region. Aerosol organic enrichment and subsequent evolution to predominantly accumulation mode have been observed. This enrichment and its simultaneous size-growth caused it to get brighter during the biomass burning season. A very clear enhancement (20

  17. Partitions and vertical profiles of 9 endocrine disrupting chemicals in an estuarine environment: Effect of tide, particle size and salinity.

    PubMed

    Yang, Lihua; Cheng, Qiao; Lin, Li; Wang, Xiaowei; Chen, Baowei; Luan, Tiangang; Tam, Nora F Y

    2016-04-01

    Phenolic endocrine disrupting chemicals (EDCs) in an estuarine water column in a depth profile of five water layers (0.05 D, 0.20 D, 0.60 D, 0.80 D and 0.90 D, D = Depth, 10.7 ± 0.7 m) and their corresponding environmental parameters (tide, salinity and particle size) were investigated over a year. Water sample from each layer was further separated into three fractions, which were dissolved, coarse (SPM-D, Φ ≥ 2.7 μm) and fine (SPM-F, 2.7 μm > Φ ≥ 0.7 μm) suspended particulate matters. Most of EDCs in the water column were presented in the dissolved fraction. Vertical profiles of salinity fluctuations showed that the upper water layer was most influenced by upstream flow. Estriol (E3), mestranol (Mes) and 17α-ethynylestradiol (EE2) concentrations were significantly higher in ebb tide than in flood tide, indicating that EDCs mainly came from terrestrial source, the upstream flow. Dissolved EDCs also exhibited high levels in the surface layer (0.05 D) due to the upstream source and atmosphere deposition, followed by the bottom layer (0.90 D) owing to the re-suspension of EDCs-containing sediment. Compared to the dissolved phase, the contents of BPA, Mes and EE2 in the solid phase were affected by particle size and exhibited a trend of SPM-F > SPM-D > sediment. On the other hand, the concentrations of octylphenol (OP) and t-nonylphenol (NP), the degradation products from common nonionic surfactants, in sediment were higher than those in suspended particles, and NP concentration was higher in flood tide than that in ebb tide. For both SPM-D and SPM-F, their corresponding EDCs concentrations were negatively related to SPM concentrations due to particle concentration effect (PCE). Owing to the "salting-out effect", salinity pushed EDCs from dissolved fraction to particulate or sedimentary phase.

  18. Partitions and vertical profiles of 9 endocrine disrupting chemicals in an estuarine environment: Effect of tide, particle size and salinity.

    PubMed

    Yang, Lihua; Cheng, Qiao; Lin, Li; Wang, Xiaowei; Chen, Baowei; Luan, Tiangang; Tam, Nora F Y

    2016-04-01

    Phenolic endocrine disrupting chemicals (EDCs) in an estuarine water column in a depth profile of five water layers (0.05 D, 0.20 D, 0.60 D, 0.80 D and 0.90 D, D = Depth, 10.7 ± 0.7 m) and their corresponding environmental parameters (tide, salinity and particle size) were investigated over a year. Water sample from each layer was further separated into three fractions, which were dissolved, coarse (SPM-D, Φ ≥ 2.7 μm) and fine (SPM-F, 2.7 μm > Φ ≥ 0.7 μm) suspended particulate matters. Most of EDCs in the water column were presented in the dissolved fraction. Vertical profiles of salinity fluctuations showed that the upper water layer was most influenced by upstream flow. Estriol (E3), mestranol (Mes) and 17α-ethynylestradiol (EE2) concentrations were significantly higher in ebb tide than in flood tide, indicating that EDCs mainly came from terrestrial source, the upstream flow. Dissolved EDCs also exhibited high levels in the surface layer (0.05 D) due to the upstream source and atmosphere deposition, followed by the bottom layer (0.90 D) owing to the re-suspension of EDCs-containing sediment. Compared to the dissolved phase, the contents of BPA, Mes and EE2 in the solid phase were affected by particle size and exhibited a trend of SPM-F > SPM-D > sediment. On the other hand, the concentrations of octylphenol (OP) and t-nonylphenol (NP), the degradation products from common nonionic surfactants, in sediment were higher than those in suspended particles, and NP concentration was higher in flood tide than that in ebb tide. For both SPM-D and SPM-F, their corresponding EDCs concentrations were negatively related to SPM concentrations due to particle concentration effect (PCE). Owing to the "salting-out effect", salinity pushed EDCs from dissolved fraction to particulate or sedimentary phase. PMID:26736056

  19. The effects of vehicle emissions and nucleation events on vertical particle concentration profiles around urban office buildings

    NASA Astrophysics Data System (ADS)

    Quang, T. N.; He, C.; Morawska, L.; Knibbs, L. D.; Falk, M.

    2012-01-01

    Despite its role in determining both indoor and outdoor human exposure to anthropogenic particles, there is limited information describing vertical profiles of particle concentrations in urban environments, especially for ultrafine particles. Furthermore, the results of the few studies performed have been inconsistent. As such this study aimed to assess the influence of vehicle emissions and nucleation formation on particle concentrations (PN and PM2.5) at different heights around three urban office buildings located next to busy roads in Brisbane, Australia, and place these results in the broader context of the existing literature. Two sets of instruments were used to simultaneously measure PN size distribution, PN and PM2.5 concentrations, respectively, for up to three weeks each at three office buildings. The results showed that both PN and PM2.5 concentrations around building envelope were influenced by vehicle emissions and new particle formation, and that they exhibited variability across the three different office buildings. During the nucleation event, PN concentrations increased (21-46%), while PM2.5 concentrations decreased (36-52%) with height at all three buildings. This study has shown an underappreciated role of nucleation in producing particles that can affect large numbers of people, due to the high density and occupancy of urban office buildings and the fact that the vast majority of people's time is spent indoors. These findings highlight important new information related to the previously overlooked role of particle formation in the urban atmosphere and its potential effects on selection of air intake locations and appropriate filter types when designing or upgrading mechanical ventilation systems in urban office buildings. The results also serve to better define particle behaviour and variability around building envelopes, which has implications for studies of both human exposure and particle dynamics.

  20. A new method to measure bowen ratios using high resolution vertical dry and wet bulb temperature profiles

    NASA Astrophysics Data System (ADS)

    Euser, T.; Luxemburg, W.; Everson, C.; Mengistu, M.; Clulow, A.; Bastiaanssen, W.

    2013-06-01

    The Bowen ratio surface energy balance method is a relatively simple method to determine the latent heat flux and the actual land surface evaporation. Despite its simplicity, the Bowen ratio method is generally considered to be unreliable due to the use of two-level sensors that are installed by default in operational Bowen ratio systems. In this paper we present the concept of a new measurement methodology to estimate the Bowen ratio from high resolution vertical dry and wet bulb temperature profiles. A short field experiment with Distributed Temperature Sensing (DTS) in a fibre optic cable having 13 levels was undertaken. A dry and a wetted section of a fibre optic cable were suspended on a 6 m high tower installed over a sugar beet trial near Pietermaritzburg (South Africa). Using the DTS cable as a psychrometer, a near continuous observation of vapour pressure and temperature at 0.20 m intervals was established. These data allows the computation of the Bowen ratio with a high precision. By linking the Bowen ratio to net radiation and soil heat flux, the daytime latent heat flux was estimated. The latent heat flux derived from DTS-based Bowen ratio (BR-DTS) showed consistent agreement (correlation coefficients between 0.97 and 0.98) with results derived from eddy covariance, surface layer scintillometer and surface renewal techniques. The latent heat from BR-DTS overestimated the latent heat derived with the eddy covariance by 4% and the latent heat derived with the surface layer scintillometer by 8%. Through this research, a new window is opened to engage on simplified, inexpensive and easy to interpret in situ measurement techniques for measuring evaporation.

  1. Shallow 3-D vertical seismic profiling around a contaminant withdrawal well on the Lawrence Livermore National Laboratory Site

    SciTech Connect

    Rector, J.; Bainer, R.; Milligan, P.; Tong, C.

    1997-01-30

    One of the major problems associated with ground water contaminant remediation is well placement. Optimal-placement of wells requires an accurate knowledge of geologic structure and stratigraphy in the near surface sediments and rock (0 to 100 m). Without the development of remote imaging provided by geophysical techniques, the required spacing between treatment wells may be less than 2 m in order to be confident that all contaminant reservoirs had been remediated. One method for characterizing geologic structure and stratigraphy in the near surface is vertical seismic profiling (VSP), a technique often used on deep exploration wells to calibrate surface seismic reflection data. For near-surface applications, VSP data can be acquired efficiently using an array of hydrophones lowered into a fluid-filled borehole (Milligan et al, 1997). In this paper we discuss the acquisition and processing of a 3-D VSP collected at a shallow remediation site located on the grounds of the Lawrence Livermore National Laboratory (LLNL) near Livermore, California. The site was used by the United States Navy as an air training base. At this time, initial releases of hazardous materials to the environment occurred in the form of solvents [volatile organic compounds (VOCs)] that were used for the cleaning of airplanes and their parts. Gasoline, diesel and other petroleum-based compounds are also known to have leaked into the ground. California Research and Development Company, a subsidy of Standard Oil, occupied the southeastern portion of the site from 1950 to 1954. The first releases of radioactive materials to the environment occurred at this time, with the beginning of testing of radioactive materials at the site. In 1952, LLNL acquired the site. Additional releases of VOCS, polychlorinated biphenyls (PCBs), metals, radionuclides (primarily tritium), gasoline and pesticides have occurred since. These releases were due to localized spills, landfills, surface impoundments, disposal pits

  2. Rapid vertical transport: evidence from an isotopic and chemical lysimeter-profile in a porous aquifer, Wagna, Leibnitzer Feld, Austria.

    NASA Astrophysics Data System (ADS)

    Kralik, Martin; Fank, Johannes; Humer, Franko

    2013-04-01

    Isotopic behaviour, hydrochemical exchange and variation of transport velocities in the unsaturated zone and at the transition unsaturated and saturated zone are still unknown in many groundwater bodies. This vertical transport time through the unsaturated zone has to be added by estimating the Mean Residence Time (MRT) of groundwater by gas tracers as e.g. 3He, 85Kr, CFCs, SF6 etc. At the lysimeter station Wagna (Leibnitzer Feld, Styria, Austria) a dense depth-profile (n=24 suction cups) over the transition unsaturated and saturated zone was sampled 6 month after an unusual wet summer. On all samples oxygen and hydrogen isotopes as well as major ions were analysed. Tritium was measured at the top and the bottom of the saturated zone. The heavier isotopes and the smaller ion-concentration in the water of the unsaturated zone approach the surface of the saturated zone with a gradient. This gradient continues in a steep form over the depth of the saturated zone. The tritium content on top of the saturated zone is significantly higher than at the bottom of the zone (11 and 9.7 TU), indicating summer water with a higher tritium content of 11 - 12 TU. The unusual high summer precipitation (150%) seem to have arrived quicker (4.4-6.6 m/a) than normal (2.5 m/a) at the saturated zone in the depth of 3.3 m. All the major ions are less concentrated in the unsaturated zone with the exception of nitrate supporting the idea of diluted ion-concentrations in strong summer precipitations, but enhanced nitrate leaching. Isotope data and tracer gas measurements of 14 monitoring wells in the groundwater body surrounding the lysimeter allow calculating the timing and the importance of summer precipitation for the groundwater recharge in unconfined aquifers in humid climates.

  3. A direct detection 1.6μm DIAL with three wavelengths for high accuracy measurements of vertical CO2 concentration and temperature profiles

    NASA Astrophysics Data System (ADS)

    Shibata, Yasukuni; Nagasawa, Chikao; Abo, Makoto

    2013-10-01

    The accurate vertical CO2 profiles in the troposphere are highly desirable in the inverse techniques to improve quantification and understanding of the global budget of CO2 and also global climate changes. Moreover, wind information is an important parameter for transport simulations and inverse estimation of surface CO2 flux. A differential absorption lidar (DIAL) is an attractive method for obtaining vertical CO2 profiles and we have developed an 1.6μm DIAL system to perform simultaneous measurements of CO2 concentration, atmospheric temperature profile and wind profile. The absorption cross sections of gas and air density depends on atmospheric temperature and pressure. Then precise temperature and pressure profiles are necessary for accurate CO2 mixing ratio measurement by DIAL. Laser beams of three wavelengths around a CO2 absorption line are transmitted alternately to the atmosphere for simultaneous measurements of CO2 concentration and temperature. The receiving optics include the near-infrared photomultiplier tube and a fiber Bragg grating (FBG) filter to detect a Doppler shift.

  4. Inversely estimating the vertical profile of the soil CO2 production rate in a deciduous broadleaf forest using a particle filtering method.

    PubMed

    Sakurai, Gen; Yonemura, Seiichiro; Kishimoto-Mo, Ayaka W; Murayama, Shohei; Ohtsuka, Toshiyuki; Yokozawa, Masayuki

    2015-01-01

    Carbon dioxide (CO2) efflux from the soil surface, which is a major source of CO2 from terrestrial ecosystems, represents the total CO2 production at all soil depths. Although many studies have estimated the vertical profile of the CO2 production rate, one of the difficulties in estimating the vertical profile is measuring diffusion coefficients of CO2 at all soil depths in a nondestructive manner. In this study, we estimated the temporal variation in the vertical profile of the CO2 production rate using a data assimilation method, the particle filtering method, in which the diffusion coefficients of CO2 were simultaneously estimated. The CO2 concentrations at several soil depths and CO2 efflux from the soil surface (only during the snow-free period) were measured at two points in a broadleaf forest in Japan, and the data were assimilated into a simple model including a diffusion equation. We found that there were large variations in the pattern of the vertical profile of the CO2 production rate between experiment sites: the peak CO2 production rate was at soil depths around 10 cm during the snow-free period at one site, but the peak was at the soil surface at the other site. Using this method to estimate the CO2 production rate during snow-cover periods allowed us to estimate CO2 efflux during that period as well. We estimated that the CO2 efflux during the snow-cover period (about half the year) accounted for around 13% of the annual CO2 efflux at this site. Although the method proposed in this study does not ensure the validity of the estimated diffusion coefficients and CO2 production rates, the method enables us to more closely approach the "actual" values by decreasing the variance of the posterior distribution of the values.

  5. A Sensitivity Study of the Aircraft Vortex Spacing System (AVOSS) Wake Predictor Algorithm to the Resolution of Input Meteorological Profiles

    NASA Technical Reports Server (NTRS)

    Rutishauser, David K.; Butler, Patrick; Riggins, Jamie

    2004-01-01

    The AVOSS project demonstrated the feasibility of applying aircraft wake vortex sensing and prediction technologies to safe aircraft spacing for single runway arrivals. On average, AVOSS provided spacing recommendations that were less than the current FAA prescribed spacing rules, resulting in a potential airport efficiency gain. Subsequent efforts have included quantifying the operational specifications for future Wake Vortex Advisory Systems (WakeVAS). In support of these efforts, each of the candidate subsystems for a WakeVAS must be specified. The specifications represent a consensus between the high-level requirements and the capabilities of the candidate technologies. This report documents the beginnings of an effort to quantify the capabilities of the AVOSS Prediction Algorithm (APA). Specifically, the APA horizontal position and circulation strength output sensitivity to the resolution of its wind and turbulence inputs is examined. The results of this analysis have implications for the requirements of the meteorological sensing and prediction systems comprising a WakeVAS implementation.

  6. Airborne in situ vertical profiling of HDO / H216O in the subtropical troposphere during the MUSICA remote sensing validation campaign

    NASA Astrophysics Data System (ADS)

    Dyroff, C.; Sanati, S.; Christner, E.; Zahn, A.; Balzer, M.; Bouquet, H.; McManus, J. B.; Gonzalez-Ramos, Y.; Schneider, M.

    2015-05-01

    Vertical profiles of water vapor (H2O) and its isotope ratio D / H expressed as δD(H2O) were measured in situ by the ISOWAT II diode-laser spectrometer during the MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water (MUSICA) airborne campaign. We present recent modifications of the instrument design. The instrument calibration on the ground as well as in flight is described. Based on the calibration measurements, the humidity-dependent uncertainty of our airborne data is determined. For the majority of the airborne data we achieved an accuracy (uncertainty of the mean) of Δ(δD) ≈10‰. Vertical profiles between 150 and ~7000 m were obtained during 7 days in July and August 2013 over the subtropical North Atlantic Ocean near Tenerife. The flights were coordinated with ground-based (Network for the Detection of Atmospheric Composition Change, NDACC) and space-based (Infrared Atmospheric Sounding Interferometer, IASI) FTIR remote sensing measurements of δD(H2O) as a means to validate the remote sensing humidity and δD(H2O) data products. The results of the validation are presented in detail in a separate paper (Schneider et al., 2014). The profiles were obtained with a high vertical resolution of around 3 m. By analyzing humidity and δD(H2O) correlations we were able to identify different layers of air masses with specific isotopic signatures. The results are discussed.

  7. Airborne in situ vertical profiling of HDO/H216O in the subtropical troposphere during the MUSICA remote sensing validation campaign

    NASA Astrophysics Data System (ADS)

    Dyroff, C.; Sanati, S.; Christner, E.; Zahn, A.; Balzer, M.; Bouquet, H.; McManus, J. B.; González-Ramos, Y.; Schneider, M.

    2015-01-01

    Vertical profiles of water vapor (H2O) and its isotope ratio D / H expressed as δ D(H2O were measured in situ by the ISOWAT II diode-laser spectrometer during the MUlti-platform remote Sensing of Isotopologues for investigating the Cycle of Atmospheric water (MUSICA) airborne campaign. We present recent modifications of the instrument design. The instrument calibration on the ground as well as in flight is described. Based on the calibration measurements, the humidity-dependent uncertainty of our airborne data is determined. For the majority of the airborne data we achieved an accuracy (uncertainty of the mean) of Δ(δ D) ≈ 10‰. Vertical profiles between 150 and ~7000 m were obtained during 7 days in July and August 2013 over the subtropical North Atlantic Ocean near Tenerife. The flights were coordinated with ground-based (Network for the Detection of Atmospheric Composition Change, NDACC) and space-based (Infrared Atmospheric Sounding Interferometer, IASI) FTIR remote-sensing measurements of δ D(H2O) as a means to validate the remote sensing humidity and δ D(H2O) data products. The results of the validation are presented in detail in a separate paper (Schneider et al., 2014). The profiles were obtained with a high vertical resolution of around 3 m. By analyzing humidity and δ D(H2O) correlations we were able to identify different layers of airmasses with specific isotopic signatures. The results are discussed.

  8. Particle pH Inferred from Aircraft Data: Validation and Geographical, Vertical and Seasonal Characteristics with Case Studies from the WINTER Campaign

    NASA Astrophysics Data System (ADS)

    Guo, H.; Weber, R. J.; Nenes, A.; Sullivan, A.; Thornton, J. A.; Lopez-Hilfiker, F.; Jimenez, J. L.; Campuzano Jost, P.; Schroder, J. C.; Dibb, J. E.

    2015-12-01

    Particle pH is a critical but poorly understood factor that affects many aerosol processes and properties, including aerosol composition, concentrations, geochemical cycles, and aerosol toxicity. Here we assess the prediction of pH from aircraft data, report pH as a function of geographical location and altitude for different seasons, and investigate causes for variability in pH-dependent aerosol components, such as nitrate. pH is generally predicted with a thermodynamic model since it is difficult to measure directly. We used ISORROPIA-II with particle and selected gas inorganic species, along with RH and T as inputs to calculate aerosol pH. Data are from three aircraft studies: WINTER (2015 Feb-Mar) and NEAQS (2004 July-Aug), both over the northeastern US, and SENEX (2013 Jun-July) over the southeastern US. pH was validated by comparing measured and predicted partitioning of ammonia and nitric acid. The effect of inevitable sample heating associated with aircraft measurements was minimal since partitioning of measured semi-volatile components based on ambient T and RH were accurately predicted. Overall, pH determined from WINTER, NEAQS, and SENEX for altitudes up to 5000 m ranged between -0.4 and 1.9 (10-90% percentiles, mean±SD=0.9±1.0), similar to what we have observed at ground-based sites in the southeastern US. Coupling between water vapor concentrations, temperature, particle composition, liquid water content and particle pH on partitioning of nitric acid-nitrate observed during the WINTER campaign will be investigated.

  9. Vertical profiling of marine aerosol, dust and their mixtures utilizing the synergy of sunphotometer and lidar measurements

    NASA Astrophysics Data System (ADS)

    Tsekeri, Alexandra; Amiridis, Vassilis; Lopatin, Anton; Marinou, Eleni; Engelman, Ronny; Baars, Holger; Wandinger, Ulla; Ansmann, Albert; Solomos, Stavros; Dubovik, Oleg; Schüttemeyer, Dirk

    2015-04-01

    combines ground-based lidar and sunphotometer measurements, developed in the frame of ACTRIS. Our results for cases of marine-only, dust-only and mixtures of marine and dust retrievals provide an evaluation of the algorithm capabilities for marine environments, producing vertical profiles of physical and optical properties of marine and dust particles.

  10. Dependence of the drizzle growth process on the cloud top height and its relevance to the aerosol vertical profile

    NASA Astrophysics Data System (ADS)

    Kawamoto, K.; Suzuki, K.

    2013-12-01

    Transitional processes among cloud droplets, drizzle and raindrops are still uncertain and more efforts are required for the better understanding. In this situation, difference in the drizzle growth process was examined according to the cloud top height using the CloudSat and MODIS synergetic datasets. From the CloudSat products such as 2B-GEOPROF, 2B-TAU, ECMWF-AUX, only one-layered water clouds whose top temperatures were warmer than 273K were extracted over China (a circular area having a diameter of 1800km of the center at 35°N and 120°E) and over ocean (a circular area having a diameter of 1500km of the center at 35°N and 150°E). Then a threshold of 3km of the cloud top height was adopted to divide the extracted clouds into upper and lower cases. First, the probability distribution functions (PDF) of the cloud droplet number density (Nc) and the effective particle radius (Re) were calculated for these four cases (land/ocean/upper/lower). Nc was obtained assuming the adiabatic liquid water content from MODIS-derived cloud optical depth and Re. Oceanic clouds had fewer Nc than land clouds, and almost the same for upper and lower cases. Land clouds had more Nc for the lower case than for the higher case. On the other hand, oceanic clouds had larger Re than land clouds, and almost the same for upper and lower cases. Land clouds had smaller Re for the lower case than for the higher case. These results quite agreed with our existing knowledge on the vertical profile of the aerosol number concentration over ocean (pristine) and land (polluted). Although the number of aerosol particles is fewer and almost the same regardless of the height over the ocean, it is more near the surface and it rapidly decreases according to the height over the land. Next, examining PDF of the radar reflectivity (Ze), we found that although PDFs of Ze were almost the same for oceanic clouds regardless of the cloud top height, PDF of land lower clouds were less frequent at around from

  11. Near Real Time Vertical Profiles of Clouds and Aerosols from the Cloud-Aerosol Transport System (CATS) on the International Space Station

    NASA Astrophysics Data System (ADS)

    Yorks, J. E.; McGill, M. J.; Nowottnick, E. P.

    2015-12-01

    Plumes from hazardous events, such as ash from volcanic eruptions and smoke from wildfires, can have a profound impact on the climate system, human health and the economy. Global aerosol transport models are very useful for tracking hazardous plumes and predicting the transport of these plumes. However aerosol vertical distributions and optical properties are a major weakness of global aerosol transport models, yet a key component of tracking and forecasting smoke and ash. The Cloud-Aerosol Transport System (CATS) is an elastic backscatter lidar designed to provide vertical profiles of clouds and aerosols while also demonstrating new in-space technologies for future Earth Science missions. CATS has been operating on the Japanese Experiment Module - Exposed Facility (JEM-EF) of the International Space Station (ISS) since early February 2015. The ISS orbit provides more comprehensive coverage of the tropics and mid-latitudes than sun-synchronous orbiting sensors, with nearly a three-day repeat cycle. The ISS orbit also provides CATS with excellent coverage over the primary aerosol transport tracks, mid-latitude storm tracks, and tropical convection. Data from CATS is used to derive properties of clouds and aerosols including: layer height, layer thickness, backscatter, optical depth, extinction, and depolarization-based discrimination of particle type. The measurements of atmospheric clouds and aerosols provided by the CATS payload have demonstrated several science benefits. CATS provides near-real-time observations of cloud and aerosol vertical distributions that can be used as inputs to global models. The infrastructure of the ISS allows CATS data to be captured, transmitted, and received at the CATS ground station within several minutes of data collection. The CATS backscatter and vertical feature mask are part of a customized near real time (NRT) product that the CATS processing team produces within 6 hours of collection. The continuous near real time CATS data

  12. Technical Note: Variance-covariance matrix and averaging kernels for the Levenberg-Marquardt solution of the retrieval of atmospheric vertical profiles

    NASA Astrophysics Data System (ADS)

    Ceccherini, S.; Ridolfi, M.

    2010-03-01

    The variance-covariance matrix (VCM) and the averaging kernel matrix (AKM) are widely used tools to characterize atmospheric vertical profiles retrieved from remote sensing measurements. Accurate estimation of these quantities is essential for both the evaluation of the quality of the retrieved profiles and for the correct use of the profiles themselves in subsequent applications such as data comparison, data assimilation and data fusion. We propose a new method to estimate the VCM and AKM of vertical profiles retrieved using the Levenberg-Marquardt iterative technique. We apply the new method to the inversion of simulated limb emission measurements. Then we compare the obtained VCM and AKM with those resulting from other methods already published in the literature and with accurate estimates derived using statistical and numerical estimators. The proposed method accounts for all the iterations done in the inversion and provides the most accurate VCM and AKM. Furthermore, it correctly estimates the VCM and the AKM also if the retrieval iterations are stopped when a physically meaningful convergence criterion is fulfilled, i.e. before achievement of the numerical convergence at machine precision. The method can be easily implemented in any Levenberg-Marquardt iterative retrieval scheme, either constrained or unconstrained, without significant computational overhead.

  13. Technical Note: Variance-covariance matrix and averaging kernels for the Levenberg-Marquardt solution of the retrieval of atmospheric vertical profiles

    NASA Astrophysics Data System (ADS)

    Ceccherini, S.; Ridolfi, M.

    2009-11-01

    The variance-covariance matrix (VCM) and the averaging kernel matrix (AKM) are widely used tools to characterize atmospheric vertical profiles retrieved from remote sensing measurements. Accurate estimation of these quantities is essential for both the evaluation of the quality of the retrieved profiles and for the correct use of the profiles themselves in subsequent applications such as data comparison, data assimilation and data fusion. We propose a new method to estimate the VCM and AKM of vertical profiles retrieved using the Levenberg-Marquardt iterative technique. We apply the new method to the inversion of simulated limb emission measurements. Then we compare the obtained VCM and AKM with those resulting from other methods already published in the literature and with accurate estimates derived using statistical and numerical estimators. The proposed method accounts for all the iterations done in the inversion and provides the most accurate VCM and AKM. The method can be easily implemented in any Levenberg-Marquardt iterative retrieval scheme, either constrained or unconstrained, without significant computational overhead.

  14. Comparisons of cloud ice mass content retrieved from the radar-infrared radiometer method with aircraft data during the second international satellite cloud climatology project regional experiment (FIRE-II)

    SciTech Connect

    Matrosov, S.Y. |; Heymsfield, A.J.; Kropfli, R.A.; Snider, J.B.

    1996-04-01

    Comparisons of remotely sensed meteorological parameters with in situ direct measurements always present a challenge. Matching sampling volumes is one of the main problems for such comparisons. Aircraft usually collect data when flying along a horizontal leg at a speed of about 100 m/sec (or even greater). The usual sampling time of 5 seconds provides an average horizontal resolution of the order of 500 m. Estimations of vertical profiles of cloud microphysical parameters from aircraft measurements are hampered by sampling a cloud at various altitudes at different times. This paper describes the accuracy of aircraft horizontal and vertical coordinates relative to the location of the ground-based instruments.

  15. A Contribution to the Sea-Ice Model Intercomparison Project 2 (SIMIP2) Thermodynamic Sea-Ice Models Assessment : Impact of Vertical Resolution, Vertical Salinity Profile, and Salinity- and Temperature-Dependent Thermal Properties

    NASA Astrophysics Data System (ADS)

    Fichefet, T.; Vancoppenolle, M.

    2004-12-01

    Results from a sophisticated thermodynamic sea-ice model are presented. The model has the following peculiarities. First, the sea-ice pack is represented by several layers of snow on top of several layers of ice, and different ways of specifying the number and thickness of vertical layers are possible. Second, the heat-diffusion equation and its boundary conditions explicitly take into account the thermal damping effect of the brine pockets trapped into the ice through temperature- and salinity-dependent thermal properties, but density is nevertheless a constant. The main experiment consists in an almost-one-year integration of the model following the SIMIP2 (Sea-Ice Model Intercomparision Project) specifications, i.e., a Lagrangian multiyear undeformed ice floe forced by observed hourly atmospheric and monthly oceanic data fields. Model results are compared to weekly observations of ice and snow thicknesses. Snow precipitations have to be increased by 50% for the snow thickness to be correctly reproduced, supporting gauge problems already reported in the past. Ice thickness shows good overall agreement, especially in winter, and an underestimation of around 10 cm of surface melting in summer. Sensitivity experiments show that the effect of salinity and temperature through thermal properties is significant. The non-linear vertical salinity profile can be replaced by a linear profile with same mean salinity. Finally, the simplest resolution which conserves the main features of the results gathers one layer in the snow and between 5 and 10 layers in the ice.

  16. First look at the NOAA Aircraft-based Tropospheric Ozone Climatology

    NASA Astrophysics Data System (ADS)

    Leonard, M.; Petropavlovskikh, I. V.; McClure-Begley, A.; Lin, M.; Tarasick, D.; Johnson, B. J.; Oltmans, S. J.

    2015-12-01

    The Global Greenhouse Gas Reference Network's aircraft program has operated since the 1990s as part of the NOAA Global Monitoring Division network to capture spatial and temporal variability in greenhouse tracers (i.e. CO2, CO, N2O, methane, SF6, halo- and hydro-carbons). Since 2005 the suite of airborne measurements also includes ozone, humidity and temperature profiling through the troposphere (up to 8 km). Light commercial aircraft are equipped with modified 2B Technology ozone monitors (Model 205DB), incorporate temperature and humidity probes, and include global positioning system instrumentation. The dataset was analyzed for tropospheric ozone variability at five continental US stations. As site locations within the Tropospheric Aircraft Ozone Measurement Program have flights only once (four times at one site) a month and begun a decade ago, this raises the question of whether this sampling frequency allows the derivation of an accurate vertical climatology of ozone values. We interpret the representativeness of the vertical and seasonal ozone distribution from aircraft measurements using multi-decadal hindcast simulations conducted with the GFDL AM3 chemistry-climate model. When available, climatology derived from co-located ozone-sonde data will be used for comparisons. The results of the comparisons are analyzed to establish altitude ranges in the troposphere where the aircraft climatology would be deemed to be the most representative. Aircraft-based climatologies are tested from two approaches: comparing the aircraft-based climatology to the daily sampled model and to the subset of model data with matching aircraft dates. Whenever the model and aircraft climatologies show significant seasonal differences, further information is gathered from a seasonal Gaussian distribution plot. We will report on the minimum frequency in flights that can provide adequate climatological representation of seasonal and vertical variability in tropospheric ozone.

  17. Biases of CO2 Storage in Eddy Flux Measurements pertinent to Vertical Configurations of a Profile System and CO2 Density Averaging

    SciTech Connect

    Yang, Bai; Hanson, Paul J; Riggs, Jeffery S; Pallardy, Stephen G.; Hosman, K. P.; Meyers, T. P.; Wullschleger, Stan D; Gu, Lianhong; Heuer, Mark

    2007-01-01

    CO2 storage in a 30-minute period in a tall forest canopy often makes significant contributions to net ecosystem exchange (NEE) in the early morning and at night. When CO2 storage is properly measured and taken into account, underestimations of NEE on calm nights can be greatly reduced. Using CO2 data from a 12-level profile, we demonstrate that the lower canopy layer (below the thermal inversion) is a disproportional contributor to the total CO2 storage. This is because time derivative of CO2 density ( c/ t) generally shows increasing magnitude of mean and standard deviation with decreasing heights at night and from sunrise to 1000 hr in both growing and dormant seasons. Effects of resolution and configuration in a profiling system on the accuracy of CO2 storage estimation are evaluated by comparing subset profiles to the 12-level benchmark profile. It is demonstrated that the effectiveness of a profiling system in estimating CO2 storage is not only determined by its number of sampling levels but, more importantly, by its vertical configuration. To optimize a profile, one needs to balance the influence of two factors, c/ t and layer thickness, among all vertical sections within a forest. As a key contributor to the total CO2 storage, the lower canopy (with relatively large means and standard deviations of c/ t) requires a higher resolution in a profile system than the layers above. However, if the upper canopy is over-sparsely sampled relative to the lower canopy, the performance of a profile system might be degraded since, in such a situation, the influence of layer thickness dominates over that of c/ t. We also find that, because of different level of complexity in canopy structure, more sampling levels are necessary at our site in order to achieve the same level of accuracy as at a boreal aspen site. These results suggest that, in order to achieve an adequate accuracy in CO2 storage measurements, the number of sampling levels in a profile and its design should

  18. Aircraft control position indicator

    NASA Technical Reports Server (NTRS)

    Dennis, Dale V. (Inventor)

    1987-01-01

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

  19. Decoupling of deformation in the Upper Rhine Graben sediments. Seismic reflection and diffraction on 3-component Vertical Seismic Profiling (Soultz-sous-Forêts area)

    NASA Astrophysics Data System (ADS)

    Place, Joachim; Diraison, Marc; Naville, Charles; Géraud, Yves; Schaming, Marc; Dezayes, Chrystel

    2010-07-01

    A contribution to the definition of the structural pattern of the Soultz-sous-Forêts EGS (Enhanced Geothermal System) is presented here. After reprocessing, the PHN84J seismic reflection profile highlights the tilted blocks of the Merkwiller-Péchelbronn oilfield. In the Soultz-sous-Forêts horst, complex fault patterns are observed: the Hermerswiller normal fault flattens at depth and is rooted in decollements occurring in Triassic salt or clay series, while other steep normal faults affect underlying sedimentary formations and basement. Some methods for the exploitation of a seismic diffraction recorded by multi-component Vertical Seismic Profiling (VSP) are also illustrated to locate the diffractor without specific data processing. Polarisation and travel time analysis of a diffraction event recorded in the GPK1 borehole are analysed, and its exploitation combined with seismic reflection helps defining a tilted block geometry.

  20. Influence of atmospheric parameters on vertical profiles and horizontal transport of aerosols generated in the surf zone

    NASA Astrophysics Data System (ADS)

    Kusmierczyk-Michulec, J.; Tedeschi, G.; Van Eijk, A. M. J.; Piazzola, J.

    2013-10-01

    The vertical and horizontal transport of aerosols generated over the surf zone is discussed. Experimental data were collected during the second campaign of the Surf Zone Aerosol Experiment that took place in Duck NC (USA) in November 2007. The Empirical Orthogonal Function (EOF) method was used to analyze the vertical concentration gradients, and allowed separating the surf aerosols from aerosols advected from elsewhere. The numerical Marine Aerosol Concentration Model (MACMod) supported the analysis by confirming that the concentration gradients are more pronounced under stable conditions and that aerosol plumes are then more confined to the surface. The model also confirmed the experimental observations made during two boat runs along the offshore wind vector that surf-generated aerosols are efficiently advected out to sea over several tens of kilometers.

  1. Validation of the vertical profiles of three meteorological models using radiosondes from Antofagasta, Paranal and Llano de Chajnantor

    NASA Astrophysics Data System (ADS)

    Cortés, L.; Curé, M.

    2011-11-01

    This research presents an evaluation of three meteorological models, the Global Forecast System (GFS), the European Centre for Medium-Range Weather Forecasts (ECMWF) and the mesoscale model WRF (Weather Research and Forecasting) for three sites located in north of Chile. Cerro Moreno Airport, the Paranal Observatory and Llano de Chajnantor are located at 25, 130 and 283 km from the city of Antofagasta, respectively. Results for the three sites show that the lowest correlation and the highest errors occur at the surface. ECMWF model presents the best results at these levels for the two hours analyzed. This could be due to the fact that the ECMWF model has 91 vertical levels, compared to the 64 and 27 vertical levels of GFS and WRF models, respectively. Therefore, it can represent better the processes in the Planetary Boundary Layer (PBL). In relation to the middle and upper troposphere, the three models show good agreement.

  2. Seismic anisotropy in gas-hydrate- and gas-bearing sediments on the Blake Ridge, from a walkaway vertical seismic profile

    USGS Publications Warehouse

    Pecher, I.A.; Holbrook, W.S.; Sen, M.K.; Lizarralde, D.; Wood, W.T.; Hutchinson, D.R.; Dillon, William P.; Hoskins, H.; Stephen, R.A.

    2003-01-01

    We present results from an analysis of anisotropy in marine sediments using walkaway vertical seismic profiles from the Blake Ridge, offshore South Carolina. We encountered transverse isotropy (TI) with a vertical symmetry axis in a gas-hydrate-bearing unit of clay and claystone with Thomsen parameters ?? = 0.05 ?? 0.02 and ?? = 0.04 ?? 0.06. TI increased to ?? = 0.16 ?? 0.04 and ?? = 0.19 ?? 0.12 in the underlying gas zone. Rock physics modeling suggests that the observed TI is caused by a partial alignment of clay particles rather than high-velocity gas-hydrate veins. Similarly, the increase of TI in the gas zone is not caused by thin low-velocity gas layers but rather, we speculate, by the sharp contrast between seismic properties of an anisotropic sediment frame and elongated gas-bearing pore voids. Our results underscore the significance of anisotropy for integrating near-vertical and wide-angle seismic data.

  3. Aircraft Contrails

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Captured in this scene is a series of aircraft contrails in a high traffic region over the northern Gulf of Mexico (27.0N, 85.5W). Contrails are caused by the hot engine exhaust of high flying aircraft interacting with moisture in the cold upper atmosphere and are common occurrances of high flying aircraft.

  4. Stratospheric ozone and nitrogen dioxide total column and vertical profiles in southern Portugal during 2004-2007

    NASA Astrophysics Data System (ADS)

    Bortoli, D.; Silva, A. M.; Roselli, D.; Giovanelli, G.

    2007-10-01

    The SPATRAM (Spectrometer for Atmospheric TRAcers Monitoring) instrument has been developed by the collaboration between CGE-UE, ISAC-CNR and ENEA. SPATRAM is a multi-purpose UV-Vis-NIR spectrometer (250-950 nm). It is installed at the Observatory of the CGE since April 2004 and actually it is utilized to carry-out measurements of the zenith scattered radiation, the so-called "Passive mode", in order to retrieve-by application of DOAS (Differential Optical Absorption Spectroscopy) methodology-the vertical content of some atmospheric tracers such as Ozone (O3) and Nitrogen Dioxide (NO2). For the continuous NO2 monitoring the 425-455 nm spectral region is investigated. For the Ozone retrieval the spectral interval 320-340 nm is chosen. In this study, after a brief description of the instrument, a short explanation of the DOAS methodology and of the inversion algorithms used for the determination of the vertical distribution of the some atmospheric compounds are provided. The obtained results in terms of diurnal and seasonal variation of O3 and NO2 total column are presented. The measurements are in good agreement with the photochemical theory of NO2 and O3, showing the maximum values during the summer season and the minimum during the winter. In addition the application, to the output of the DOAS program, of sophisticated inversion schemes, using the Air Mass Factor (AMF) matrix as the kernel of the inversion algorithm, allowed for the determination of vertical distribution of some atmospheric tracers. The results obtained for NO2 and O3 are presented and discussed.

  5. NONLINEAR-APPROXIMATION TECHNIQUE FOR DETERMINING VERTICAL OZONE-CONCENTRATION PROFILES WITH A DIFFERENTIAL-ABSORPTION LIDAR

    EPA Science Inventory

    A new technique is presented for the retrieval of ozone concentration profiles from backscattered signals obtained by a multi-wavelength differential-absorption lidar (DIAL). The technique makes it possible to reduce erroneous local fluctuations induced in the ozone-concentration...

  6. Powered-lift aircraft technology

    NASA Technical Reports Server (NTRS)

    Deckert, W. H.; Franklin, J. A.

    1989-01-01

    Powered lift aircraft have the ability to vary the magnitude and direction of the force produced by the propulsion system so as to control the overall lift and streamwise force components of the aircraft, with the objective of enabling the aircraft to operate from minimum sized terminal sites. Power lift technology has contributed to the development of the jet lift Harrier and to the forth coming operational V-22 Tilt Rotor and the C-17 military transport. This technology will soon be expanded to include supersonic fighters with short takeoff and vertical landing capability, and will continue to be used for the development of short- and vertical-takeoff and landing transport. An overview of this field of aeronautical technology is provided for several types of powered lift aircraft. It focuses on the description of various powered lift concepts and their operational capability. Aspects of aerodynamics and flight controls pertinent to powered lift are also discussed.

  7. Use of the maximum entropy method to retrieve the vertical atmospheric ozone profile and predict atmospheric ozone content

    NASA Technical Reports Server (NTRS)

    Turner, B. Curtis

    1992-01-01

    A method is developed for prediction of ozone levels in planetary atmospheres. This method is formulated in terms of error covariance matrices, and is associated with both direct measurements, a priori first guess profiles, and a weighting function matrix. This is described by the following linearized equation: y = A(matrix) x X + eta, where A is the weighting matrix and eta is noise. The problems to this approach are: (1) the A matrix is near singularity; (2) the number of unknowns in the profile exceeds the number of data points, therefore, the solution may not be unique; and (3) even if a unique solution exists, eta may cause the solution to be ill conditioned.

  8. Vertical Profiles of Latent Heat Release Over the Global Tropics using TRMM Rainfall Products from December 1997 to November 2001

    NASA Technical Reports Server (NTRS)

    Tao, W.-K.; Lang, S.; Simpson, J.; Meneghini, R.; Halverson, J.; Johnson, R.; Adler, R.; Starr, David (Technical Monitor)

    2002-01-01

    NASA Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) derived rainfall information will be used to estimate the four-dimensional structure of global monthly latent heating and rainfall profiles over the global tropics from December 1997 to November 2000. Rainfall, latent heating and radar reflectivity structures between El Nino (DJF 1997-98) and La Nina (DJF 1998-99) will be examined and compared. The seasonal variation of heating over various geographic locations (i.e., oceanic vs continental, Indian ocean vs west Pacific, Africa vs S. America) will also be analyzed. In addition, the relationship between rainfall, latent heating (maximum heating level), radar reflectivity and SST is examined and will be presented in the meeting. The impact of random error and bias in stratiform percentage estimates from PR on latent heating profiles is studied and will also be presented in the meeting. Additional information is included in the original extended abstract.

  9. Vertical Profiles of Latent Heat Release Over the Global Tropics using TRMM Rainfall Products from December 1997 to November 2001

    NASA Technical Reports Server (NTRS)

    Tao, W.-K.; Lang, S.; Simpson, J.; Meneghini, R.; Halverson, J.; Johnson, R.; Adler, R.; Starr, David (Technical Monitor)

    2002-01-01

    NASA Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) derived rainfall information will be used to estimate the four-dimensional structure of global monthly latent heating and rainfall profiles over the global tropics from December 1997 to November 2000. Rainfall, latent heating and radar reflectivity structures between El Nino (DJF 1997-98) and La Nina (DJF 1998-99) will be examined and compared. The seasonal variation of heating over various geographic locations (i.e., oceanic vs continental, Indian ocean vs west Pacific, Africa vs S. America) will also be analyzed. In addition, the relationship between rainfall, latent heating (maximum heating level), radar reflectivity and SST is examined and will be presented in the meeting. The impact of random error and bias in stratiform percentage estimates from PR on latent heating profiles is studied and will also be presented in the meeting. The Goddard Cumulus Ensemble Model is being used to simulate various mesoscale convective systems that developed in different geographic locations. Specifically, the model estimated rainfall, radar reflectivity and latent heating profiles will be compared to observational data collected from TRMM field campaigns over the South China Sea in 1998 (SCSMEX), Brazil in 1999 (TRMM-LBA), and the central Pacific in 1999 (KWAJEX). Sounding diagnosed heating budgets and radar reflectivity from these experiments can provide the means to validate (heating product) as well as improve the GCE model.

  10. Vertical Profiles of Latent Heat Release over the Global Tropics Using TRMM Rainfall Products from December 1997 to November 2002

    NASA Technical Reports Server (NTRS)

    Tao, W.-K.

    2003-01-01

    NASA Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) derived rainfall information will be used to estimate the four-dimensional structure of global monthly latent heating and rainfall profiles over the global tropics from December 1997 to November 2000. Rainfall, latent heating and radar reflectivity structures between El Nino (DJF 1997-98) and La Nina (DJF 1998-99) will be examined and compared. The seasonal variation of heating over various geographic locations (i.e., oceanic vs continental, Indian ocean vs west Pacific, Africa vs S. America) will also be analyzed. In addition, the relationship between rainfall, latent heating (maximum heating level), radar reflectivity and SST is examined and will be presented in the meeting. The impact of random error and bias in straitform percentage estimates from PR on latent heating profiles is studied and will also be presented in the meeting. The Goddard Cumulus Ensemble Model is being used to simulate various mesoscale convective systems that developed in different geographic locations. Specifically, the model estimated rainfall, radar reflectivity and latent heating profiles will be compared to observational data collected from TRMM field campaigns over the South China Sea in 1998 (SCSMXX), Brazil in 1999 (TRMM- LBA), and the central Pacific in 1999 (KWAJEX). Sounding diagnosed heating budgets and radar reflectivity from these experiments can provide the means to validate (heating product) as well as improve the GCE model.

  11. Vertical Profiles of Latent Heat Release over the Global Tropics using TRMM Rainfall Products from December 1997 to November 2002

    NASA Technical Reports Server (NTRS)

    Tao, W.-K.; Lang, S.; Simpson, J.; Meneghini, R.; Halverson, J.; Johnson, R.; Adler, R.

    2003-01-01

    NASA Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) derived rainfall information will be used to estimate the four-dimensional structure of global monthly latent heating and rainfall profiles over the global tropics from December 1997 to November 2000. Rainfall, latent heating and radar reflectivity structures between El Nino (DJF 1997-98) and La Nina (DJF 1998-99) will be examined and compared. The seasonal variation of heating over various geographic locations (i.e., oceanic vs continental, Indian ocean vs west Pacific, Africa vs. S. America ) will also be analyzed. In addition, the relationship between rainfall, latent heating (maximum heating level), radar reflectivity and SST is examined and will be presented in the meeting. The impact of random error and bias in stratiform percentage estimates from PR on latent heating profiles is studied and will also be presented in the meeting. The Goddard Cumulus Ensemble Model is being used to simulate various mesoscale convective systems that developed in different geographic locations. Specifically, the model estimated rainfall, radar reflectivity and latent heating profiles will be compared to observational data collected from TRMM field campaigns over the South China Sea in 1998 (SCSMEX), Brazil in 1999 (TRMM-LBA), and the central Pacific in 1999 (KWAJEX). Sounding diagnosed heating budgets and radar reflectivity from these experiments can provide the means to validate (heating product) as well as improve the GCE model. Review of other latent heating algorithms will be discussed in the workshop.

  12. Vertical Profiles of Latent Heat Release over the Global Tropics using TRMM rainfall products from December 1997 to November 2001

    NASA Technical Reports Server (NTRS)

    Tao, W.-K.; Lang, S.; Simpson, J.; Meneghini, R.; Halverson, J.; Johnson, R.; Adler, R.

    2002-01-01

    NASA Tropical Rainfall Measuring Mission (TRMM) precipitation radar (PR) derived rainfall information will be used to estimate the four-dimensional structure of global monthly latent heating and rainfall profiles over the global tropics from December 1997 to November 2001. Rainfall, latent heating and radar reflectivity structures between El Nino (DE 1997-98) and La Nina (DJF 1998-99) will be examined and compared. The seasonal variation of heating over various geographic locations (i.e., oceanic vs continental, Indian ocean vs. west Pacific, Africa vs. S. America) will also be analyzed. In addition, the relationship between rainfall, latent heating (maximum heating level), radar reflectivity and SST is examined and will be presented in the meeting. The impact of random error and bias in strtaiform percentage estimates from PR on latent heating profiles is studied and will also be presented in the meeting. The Goddard Cumulus Ensemble Model is being used to simulate various mesoscale convective systems that developed in different geographic locations. Specifically, the model estimated rainfall, radar reflectivity and latent heating profiles will be compared to observational data collected from TRMM field campaigns over the South China Sea in 1998 (SCSMEX), Brazil in 1999 (TRMM-LBA), and the central Pacific in 1999 (KWAJEX). Sounding diagnosed heating budgets and radar reflectivity from these experiments can provide the means to validate (heating product) as well as improve the GCE model.

  13. Ground-based Measurements of Vertical Profiles and Columns of Atmospheric Trace Gases Over Toronto Using a New High-Resolution Fourier Transform Infrared Spectrometer

    NASA Astrophysics Data System (ADS)

    Wiacek, A.; Yashcov, D.; Strong, K.; Boudreau, L.; Rochette, L.; Roy, C.

    2002-12-01

    The University of Toronto Atmospheric Observatory (TAO) has recently been established at Toronto, Canada. TAO includes several instruments, with a DA8 Fourier Transform Spectrometer (DA8 FTS, manufactured by ABB Bomem Inc., Québec, Canada) serving as the primary instrument at the facility. The geographic position of TAO (43.66°N, 79.40°W) makes it well suited for long-term measurements of mid-latitude stratospheric ozone and related species, while its urban setting enables measurements of tropospheric pollution. The DA8 FTS is based on a Michelson interferometer with a maximum optical path difference of 250 cm, providing a maximum unapodized resolution of 0.0026 cm-1. It is currently equipped with KBr and CaF2 beamsplitters, and InSb and HgCdTe detectors, for coverage of the spectral range from 700 to 4100 cm-1. A new heliostat (manufactured by Aim Controls Inc., California, USA) provides active solar tracking, collecting the incoming solar radiation and directing it into the FTS. The TAO DA8 FTS incorporates a new optical design recently developed by ABB Bomem Inc., which results in a fixed optical axis through the beamsplitter (and a fixed focal point on the detector) as well as a more stable modulation efficiency. The new instrument optics will be discussed. Next, the performance of the instrument will be examined in the context of standard NDSC (Network for the Detection of Stratospheric Change) trace gas column and vertical profile retrieval techniques, which use least squares fitting algorithms (SFIT, SFIT2). TAO has been operational (weather permitting) since October 2001. We have been retrieving columns and vertical profiles of HCl, HF, CH4, OCS, C2H6, CO, N2O and NO2 since May 2002. A detailed error analysis of retrieved columns and vertical profiles has been undertaken for the above species. Future plans for the TAO FTS include comparing our measurements with satellite measurements made by MOPITT, OSIRIS, and the upcoming ACE and MAESTRO instruments

  14. 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.

  15. Specific bacterial, archaeal, and eukaryotic communities in tidal-flat sediments along a vertical profile of several meters.

    PubMed

    Wilms, Reinhard; Sass, Henrik; Köpke, Beate; Köster, Jürgen; Cypionka, Heribert; Engelen, Bert

    2006-04-01

    The subsurface of a tidal-flat sediment was analyzed down to 360 cm in depth by molecular and geochemical methods. A community structure analysis of all three domains of life was performed using domain-specific PCR followed by denaturing gradient gel electrophoresis analysis and sequencing of characteristic bands. The sediment column comprised horizons easily distinguishable by lithology that were deposited in intertidal and salt marsh environments. The pore water profile was characterized by a subsurface sulfate peak at a depth of about 250 cm. Methane and sulfate profiles were opposed, showing increased methane concentrations in the sulfate-free layers. The availability of organic carbon appeared to have the most pronounced effect on the bacterial community composition in deeper sediment layers. In general, the bacterial community was dominated by fermenters and syntrophic bacteria. The depth distribution of methanogenic archaea correlated with the sulfate profile and could be explained by electron donor competition with sulfate-reducing bacteria. Sequences affiliated with the typically hydrogenotrophic Methanomicrobiales were present in sulfate-free layers. Archaea belonging to the Methanosarcinales that utilize noncompetitive substrates were found along the entire anoxic-sediment column. Primers targeting the eukaryotic 18S rRNA gene revealed the presence of a subset of archaeal sequences in the deeper part of the sediment cores. The phylogenetic distance to other archaeal sequences indicates that these organisms represent a new phylogenetic group, proposed as "tidal-flat cluster 1." Eukarya were still detectable at 360 cm, even though their diversity decreased with depth. Most of the eukaryotic sequences were distantly related to those of grazers and deposit feeders.

  16. Specific Bacterial, Archaeal, and Eukaryotic Communities in Tidal-Flat Sediments along a Vertical Profile of Several Meters†

    PubMed Central

    Wilms, Reinhard; Sass, Henrik; Köpke, Beate; Köster, Jürgen; Cypionka, Heribert; Engelen, Bert

    2006-01-01

    The subsurface of a tidal-flat sediment was analyzed down to 360 cm in depth by molecular and geochemical methods. A community structure analysis of all three domains of life was performed using domain-specific PCR followed by denaturing gradient gel electrophoresis analysis and sequencing of characteristic bands. The sediment column comprised horizons easily distinguishable by lithology that were deposited in intertidal and salt marsh environments. The pore water profile was characterized by a subsurface sulfate peak at a depth of about 250 cm. Methane and sulfate profiles were opposed, showing increased methane concentrations in the sulfate-free layers. The availability of organic carbon appeared to have the most pronounced effect on the bacterial community composition in deeper sediment layers. In general, the bacterial community was dominated by fermenters and syntrophic bacteria. The depth distribution of methanogenic archaea correlated with the sulfate profile and could be explained by electron donor competition with sulfate-reducing bacteria. Sequences affiliated with the typically hydrogenotrophic Methanomicrobiales were present in sulfate-free layers. Archaea belonging to the Methanosarcinales that utilize noncompetitive substrates were found along the entire anoxic-sediment column. Primers targeting the eukaryotic 18S rRNA gene revealed the presence of a subset of archaeal sequences in the deeper part of the sediment cores. The phylogenetic distance to other archaeal sequences indicates that these organisms represent a new phylogenetic group, proposed as “tidal-flat cluster 1.” Eukarya were still detectable at 360 cm, even though their diversity decreased with depth. Most of the eukaryotic sequences were distantly related to those of grazers and deposit feeders. PMID:16597980

  17. General comparison of ozone vertical profiles obtained by various techniques during the 1983 MAP/GLOBUS campaign

    NASA Technical Reports Server (NTRS)

    Matthews, W. A.; Aimedieu, P.; Megie, G.; Pelon, J.; Attmannspacher, W.; Komhyr, W.; Marche, P.; De La Noe, J.; Rigaud, P.; Robbins, D. E.

    1987-01-01

    As part of the 1983 MAP/GLOBUS campaign, atmospheric ozone profile measurements were made using a large variety of different techniques both from balloon platforms and the ground. It is shown that, for most techniques, the measured height distributions agree to within + or - 5 percent with the exception of the remote visible absorption method. This + or - 5 percent uncertainty is of the order of the individual intersystem accuracy. It is suggested that since the differences with the visible absorption method are in magnitude rather than in form, the absorption cross-section data could be the possible cause for the discrepancy.

  18. Comparison of Commercial Aircraft Fuel Requirements in Regards to FAR, Flight Profile Simulation, and Flight Operational Techniques

    NASA Astrophysics Data System (ADS)

    Heitzman, Nicholas

    There are significant fuel consumption consequences for non-optimal flight operations. This study is intended to analyze and highlight areas of interest that affect fuel consumption in typical flight operations. By gathering information from actual flight operators (pilots, dispatch, performance engineers, and air traffic controllers), real performance issues can be addressed and analyzed. A series of interviews were performed with various individuals in the industry and organizations. The wide range of insight directed this study to focus on FAA regulations, airline policy, the ATC system, weather, and flight planning. The goal is to highlight where operational performance differs from design intent in order to better connect optimization with actual flight operations. After further investigation and consensus from the experienced participants, the FAA regulations do not need any serious attention until newer technologies and capabilities are implemented. The ATC system is severely out of date and is one of the largest limiting factors in current flight operations. Although participants are pessimistic about its timely implementation, the FAA's NextGen program for a future National Airspace System should help improve the efficiency of flight operations. This includes situational awareness, weather monitoring, communication, information management, optimized routing, and cleaner flight profiles like Required Navigation Performance (RNP) and Continuous Descent Approach (CDA). Working off the interview results, trade-studies were performed using an in-house flight profile simulation of a Boeing 737-300, integrating NASA legacy codes EDET and NPSS with a custom written mission performance and point-performance "Skymap" calculator. From these trade-studies, it was found that certain flight conditions affect flight operations more than others. With weather, traffic, and unforeseeable risks, flight planning is still limited by its high level of precaution. From this

  19. Calculation of zero-offset vertical seismic profiles generated by a horizontal point force acting on the surface of an elastic half-space

    USGS Publications Warehouse

    Hsi-Ping, Liu

    1990-01-01

    Impulse responses including near-field terms have been obtained in closed form for the zero-offset vertical seismic profiles generated by a horizontal point force acting on the surface of an elastic half-space. The method is based on the correspondence principle. Through transformation of variables, the Fourier transform of the elastic impulse response is put in a form such that the Fourier transform of the corresponding anelastic impulse response can be expressed as elementary functions and their definite integrals involving distance angular frequency, phase velocities, and attenuation factors. These results are used for accurate calculation of shear-wave arrival rise times of synthetic seismograms needed for data interpretation of anelastic-attenuation measurements in near-surface sediment. -Author

  20. A vertical/horizontal integration wind-induced circulation model (VH13D): A method for including surface and bottom logarithmic profiles

    NASA Astrophysics Data System (ADS)

    Wu, Jian; Tsanis, Ioannis K.

    A three-dimensional model called VH13D is developed using the vertical/horizontal integration (VHI) approach. The double-logarithmic velocity profile including both the surface and bottom sublayer characteristic lengths is employed to accurately evaluate the bottom shear stress and depth-averaged advective terms. The model is verified using analytical solutions and laboratory data for shear-induced countercurrent flows and is compared with other two- and three-dimensional circulation models in a simplified basin. It is demonstrated that the newly developed model improves the conventional two-dimensional depth-averaged and Quasi-3D models and provides a new approach to the three-dimensional wind-induced circulation model. It can efficiently simulate the wind-induced 3D current structure in lakes and estuaries under isothermal conditions.

  1. Pilot Preferences on Displayed Aircraft Control Variables

    NASA Technical Reports Server (NTRS)

    Trujillo, Anna C.; Gregory, Irene M.

    2013-01-01

    The experiments described here explored how pilots want available maneuver authority information transmitted and how this information affects pilots before and after an aircraft failure. The aircraft dynamic variables relative to flight performance were narrowed to energy management variables. A survey was conducted to determine what these variables should be. Survey results indicated that bank angle, vertical velocity, and airspeed were the preferred variables. Based on this, two displays were designed to inform the pilot of available maneuver envelope expressed as bank angle, vertical velocity, and airspeed. These displays were used in an experiment involving control surface failures. Results indicate the displayed limitations in bank angle, vertical velocity, and airspeed were helpful to the pilots during aircraft surface failures. However, the additional information did lead to a slight increase in workload, a small decrease in perceived aircraft flying qualities, and no effect on aircraft situation awareness.

  2. Configuration of the relationship of soil moistures for vertical soil profiles on a steep hillslope using a vector time series model

    NASA Astrophysics Data System (ADS)

    Kim, Sanghyun; Sun, Hanna; Jung, Sungwon

    2011-03-01

    SummaryVariation in soil moisture content throughout soil profiles during several sequential rainfalls represents the internal hydrological response on a hillslope scale. A multiplex TDR system has been operating on a mountainous hillslope to obtain the time series of soil moisture along two transects in the study area. The soil moisture modeling conducted in this study highlights our understanding of the inter-relationships between soil moistures at identical spatial locations, but at different depths. A sequential procedure was used for the time series modeling to delineate an appropriate model for application to all monitoring points. The feedback relationship of soil wetness between two different depths was expressed with the proposed vector autoregressive model. Based on the successful modeling of 31 coupled soil water histories, the vertical distributions of the stochastic model throughout the study area were obtained. The distribution of the delineated models implied a spatial distribution of the hydrological processes, such as vertical infiltration for the upper soil layers and some of the lower soil layers (38 out of 62 models), lateral redistribution and subsurface flow over bedrock mostly for the lower soil layers (24 out of 62 models) on the steep hillslope. With the use of the resultant models, applications were proposed to improve the data acquisition system, i.e. gap filling for missing data and limited prediction for an ungauged location.

  3. Vertical profiles of pollutant gases measured with passive DOAS in the Po Valley devoted to satellite and chemical model data comparison

    NASA Astrophysics Data System (ADS)

    Masieri, S.; Petritoli, A.; Kostadinov, I.; Bortoli, D.; Premuda, M.; Ravegnani, F.; Giovanelli, G.

    2009-04-01

    whose profile depends strongly on altitude [7][8]. Due to this it is also possible gain information about the atmospheric aerosol profile to set better the parameters in AMF Calculation, and then retrieve gas concentration's profiles. The NO2 concentrations measured were in the range of 0.5-25 ppb, as we expect for summer periods in rural area. GAMES (Gas Aerosol Modelling Evaluation System) model [9] was used in this work to have a reference about vertical distribution of gases (the model provides concentration profiles along 4km of altitude, with 11 growing thickness levels). Result of comparison with profile caculate by the model and profile calulate by the Multi-axis DOAS technique, is presented and then it is compared with Satellite column retrieved (with our satellite Data processor) from SCIAMACHY sensor (onboard on ENVISAT platform) and (directly NO2 Tropospheric Vertical Column provided by KNMI) from OMI (onboard on AURA platform). Good agreements between used series are shown and improvements for this methodology are discussed. One month of measurement has been taken in consideration starting from 15 May to 15 June of 2007. Vertical structure of most important trace gases calculated with model has strong correlation with the off-axis DOAS one (in some cases with R2=0,8), so better understanding of profiles and chemistry behaviour can be studied. The experience acquired within QUITSAT activity appears valuable contribution for enlargement of the DOAS applications what concern atmospheric chemistry studies, operative monitoring of the air quality over regional scale as well as satellite data validation. Deployed approaches are not restricted to NO2 but could be applied to other gases e.g. ozone, formaldehyde etc.. Key words: Off axis DOAS, NO2, CTM, AMF, gas profiles, satellite data validation, 1 2. BIBLIOGRAPHY [1] F. Evangelisti, A. Baroncelli, P. Bonasoni, G. Giovanelli, And F. Ravegnani, "Differential optical absorption spectrometer for measurement of

  4. Numerical simulation of vertical ground-water flux of the Rio Grande from ground-water temperature profiles, central New Mexico

    USGS Publications Warehouse

    Bartolino, James R.; Niswonger, Richard G.

    1999-01-01

    An important gap in the understanding of the hydrology of the Middle Rio Grande Basin, central New Mexico, is the rate at which water from the Rio Grande recharges the Santa Fe Group aquifer system. Several methodologies-including use of the Glover-Balmer equation, flood pulses, and channel permeameters- have been applied to this problem in the Middle Rio Grande Basin. In the work presented here, ground-water temperature profiles and ground-water levels beneath the Rio Grande were measured and numerically simulated at four sites. The direction and rate of vertical ground-water flux between the river and underlying aquifer was simulated and the effective vertical hydraulic conductivity of the sediments underlying the river was estimated through model calibration. Seven sets of nested piezometers were installed during July and August 1996 at four sites along the Rio Grande in the Albuquerque area, though only four of the piezometer nests were simulated. In downstream order, these four sites are (1) the Bernalillo site, upstream from the New Mexico State Highway 44 bridge in Bernalillo (piezometer nest BRN02); (2) the Corrales site, upstream from the Rio Rancho sewage treatment plant in Rio Rancho (COR01); (3) the Paseo del Norte site, upstream from the Paseo del Norte bridge in Albuquerque (PDN01); and (4) the Rio Bravo site, upstream from the Rio Bravo bridge in Albuquerque (RBR01). All piezometers were completed in the inner-valley alluvium of the Santa Fe Group aquifer system. Ground-water levels and temperatures were measured in the four piezometer nests a total of seven times in the 24-month period from September 1996 through August 1998. The flux between the surface- and ground-water systems at each of the field sites was quantified by one-dimensional numerical simulation of the water and heat exchange in the subsurface using the heat and water transport model VS2DH. Model calibration was aided by the use of PEST, a model-independent computer program that uses

  5. TES carbon monoxide validation with DACOM aircraft measurements during INTEX-B 2006

    NASA Astrophysics Data System (ADS)

    Luo, M.; Rinsland, C.; Fisher, B.; Sachse, G.; Diskin, G.; Logan, J.; Worden, H.; Kulawik, S.; Osterman, G.; Eldering, A.; Herman, R.; Shephard, M.

    2007-12-01

    Validation of Tropospheric Emission Spectrometer (TES) tropospheric CO profiles with in situ CO measurements from the Differential Absorption CO Measurement (DACOM) instrument during the Intercontinental Chemical Transport Experiment (INTEX)-B campaigns in March to May 2006 are presented. For each identified DACOM CO profile, one to three TES CO profiles are selected closest in location to the small area that the DACOM profile covers. The time differences between the comparison profiles are within 2 hours. The DACOM CO vertical profiles are adjusted by applying nearest coincident TES averaging kernels and the a priori profiles. This step accounts for the effect of the vertical resolution of the TES CO retrievals and removes the influence of the a priori assumptions in the comparisons. Comparison statistics for data taken near Houston in March 2006 show good agreement between TES and the adjusted DACOM CO profiles in the lower and middle troposphere with a correlation coefficient of 0.87. On average, the TES CO volume mixing ratio profile is 0-10% lower than the adjusted DACOM CO profile from the lower to middle troposphere. This is within the 10-20% standard deviations of the TES or DACOM CO profiles taken in the Houston area. The comparisons of TES and DACOM CO profiles near Hawaii and Anchorage in April to May 2006 are not as good. In these regions the aircraft DACOM CO profiles are characterized by plumes or enhanced CO layers, consistent with known features in the tracer fields due to transpacific transport of polluted air parcels originating from East Asia. Although TES observations over the Pacific region also show localized regions of enhanced CO, the coincidence criteria for obtaining good comparisons with aircraft measurements are challenging. The meaning of validation comparisons in profile portions where TES retrievals have little sensitivity is addressed. Examinations of characteristic parameters in TES retrievals are important in data applications.

  6. An overview of millimeter-wave spectroscopic measurements of chlorine monoxide at Thule, Greenland, February-March, 1992: Vertical profiles, diurnal variation, and longer-term trends

    NASA Technical Reports Server (NTRS)

    De Zafra, R. L.; Emmons, L. K.; Reeves, J. M.; Shindell, D. T.

    1994-01-01

    Measurements of chlorine monoxide in the stratosphere over Thule, Greenland (73.6 N, 68.4 W) were made quasi-continuously during the period February 8 to March 24, 1992, using a high-sensitivity ground based mm-wave spectrometer. These observations give diurnal, short term, and long term changes in the mixing ratio and vertical distribution of ClO. At an equivalent time after the Antarctic winter solstice, very large concentrations (up to approximately 1.5 ppbv) occur in lower stratospheric ClO, resulting in massive ozone destruction. We saw no evidence for large (approximately 1 top 1.5 ppbv) amounts of ClO in the 16-25 km range over Thule in February or March, in agreement with UARS (satellite) observations by the MLS mm-wave spectrometer for this period, and in marked contrast to UARS/MLS and ER-2 aircraft measurements over northern Europe and eastern Canada, respectively, during January, 1992. We have evidence for smaller enhancements (approximately 0.2 to 0.5 ppbv) in the 18-30 km range during late February-early March, which could result from transport of residual low NO2 air following earlier polar stratospheric cloud (PSC) processing (the last of which occurred at least one month earlier, however) or the result of chemical processing by Pinatubo aerosols. Direct influence of Pinatubo aerosols on Arctic ozone during the spring of 1992 has been difficult to assess, and this enhancement of low-altitude ClO might be a significant indicator of aerosol effects.

  7. Intercomparison of single-frequency methods for retrieving a vertical rain profile from airborne or spaceborne radar data

    NASA Technical Reports Server (NTRS)

    Iguchi, Toshio; Meneghini, Robert

    1994-01-01

    This paper briefly reviews several single-frequency rain profiling methods for an airborne or spaceborne radar. The authors describe the different methods from a unified point of view starting from the basic differential equation. This facilitates the comparisons between the methods and also provides a better understanding of the physical and mathematical basis of the methods. The application of several methods to airborne radar data taken during the Convective and Precipitation/Electrification Experiment is shown. Finally, the authors consider a hybrid method that provides a smooth transition between the Hitschfeld-Bordan method, which performs well at low attenuations, and the surface reference method, for which the relative error decreases with increasing path attenuation.

  8. Combined SAGE II-GOMOS ozone profile data set for 1984-2011 and trend analysis of the vertical distribution of ozone

    NASA Astrophysics Data System (ADS)

    Kyrölä, E.; Laine, M.; Sofieva, V.; Tamminen, J.; Päivärinta, S.-M.; Tukiainen, S.; Zawodny, J.; Thomason, L.

    2013-11-01

    We have studied data from two satellite occultation instruments in order to generate a high vertical resolution homogeneous ozone time series of 26 yr. The Stratospheric Aerosol and Gas Experiment (SAGE) II solar occultation instrument and the Global Ozone Monitoring by Occultation of Stars (GOMOS) instrument measured ozone profiles in the stratosphere and mesosphere from 1984-2005 and 2002-2012, respectively. Global coverage, good vertical resolution, and the self-calibrating measurement method make data from these instruments valuable for the detection of changes in vertical distribution of ozone over time. As both instruments share a common measurement period from 2002-2005, it is possible to inter-calibrate the data sets. We investigate how well these measurements agree with each other and combine all the data to produce a new stratospheric ozone profile data set. Above 55 km, SAGE II measurements show much less ozone than the GOMOS nighttime measurements as a consequence of the well-known diurnal variation of ozone in the mesosphere. Between 35-55 km, SAGE II sunrise and sunset measurements differ from GOMOS' measurements to different extents. Sunrise measurements show 2% less ozone than GOMOS, whereas sunset measurements show 4% more ozone than GOMOS. Differences can be explained qualitatively by the diurnal variation of ozone in the stratosphere recently observed by SMILES and modeled by chemical transport models. Between 25-35 km, SAGE II sunrise and sunset measurements and GOMOS measurements agree within 1%. The observed ozone bias between collocated measurements of SAGE II sunrise/sunset and GOMOS night measurements is used to align the two data sets. The combined data set covers the time period 1984-2011, latitudes 60° S-60° N, and the altitude range of 20-60 km. Profile data are given on a 1 km vertical grid, and with a resolution of 1 month in time and 10° in latitude. The combined ozone data set is analyzed by fitting a time series model to the

  9. Combined SAGE II-GOMOS ozone profile data set 1984-2011 and trend analysis of the vertical distribution of ozone

    NASA Astrophysics Data System (ADS)

    Kyrölä, E.; Laine, M.; Sofieva, V.; Tamminen, J.; Päivärinta, S.-M.; Tukiainen, S.; Zawodny, J.; Thomason, L.

    2013-04-01

    We have studied data from two satellite occultation instruments in order to generate a high vertical resolution homogeneous ozone time series of 26 yr. The Stratospheric Aerosol and Gas Experimen (SAGE) II solar occultation instrument from 1984-2005 and the Global Ozone Monitoring by Occultation of Stars instrument (GOMOS) from 2002-2012 measured ozone profiles in the stratosphere and mesosphere. Global coverage, good vertical resolution and the self calibrating measurement method make data from these instruments valuable for the detection of changes in vertical distribution of ozone over time. As both instruments share a common measurement period from 2002-2005, it is possible to intercalibrate the data sets. We investigate how well these measurements agree with each other and combine all the data to produce a new stratospheric ozone profile data set. Above 55 km SAGE II measurements show much less ozone than the GOMOS nighttime measurements as a consequence of the well-known diurnal variation of ozone in the mesosphere. Between 35-55 km SAGE II sunrise and sunset measurements differ from each other. Sunrise measurements show 2% less ozone than GOMOS whereas sunset measurements show 4% more ozone than GOMOS. Differences can be explained qualitatively by the diurnal variation of ozone in the stratosphere recently observed by SMILES and modelled by chemical transport models. For 25-35 km SAGE II sunrise and sunset and GOMOS agree within 1%. The observed ozone bias between collocated measurements of SAGE II sunrise/sunset and GOMOS night measurements is used to align the two data sets. The combined data set covers the time period 1984-2011, latitudes 60° S-60° N and the altitude range of 20-60 km. Profile data are given on a 1 km vertical grid, and with a resolution of one month in time and ten degrees in latitude. The combined ozone data set is analyzed by fitting a time series model to the data. We assume a linear trend with an inflexion point (so-called "hockey

  10. The influence of the tangential velocity of inner rotating wall on axial velocity profile of flow through vertical annular pipe with rotating inner surface

    NASA Astrophysics Data System (ADS)

    Sharf, Abdusalam M.; Jawan, Hosen A.; Almabsout, Fthi A.

    2014-03-01

    In the oil and gas industries, understanding the behaviour of a flow through an annulus gap in a vertical position, whose outer wall is stationary whilst the inner wall rotates, is a significantly important issue in drilling wells. The main emphasis is placed on experimental (using an available rig) and computational (employing CFD software) investigations into the effects of the rotation speed of the inner pipe on the axial velocity profiles. The measured axial velocity profiles, in the cases of low axial flow, show that the axial velocity is influenced by the rotation speed of the inner pipe in the region of almost 33% of the annulus near the inner pipe, and influenced inversely in the rest of the annulus. The position of the maximum axial velocity is shifted from the centre to be nearer the inner pipe, by increasing the rotation speed. However, in the case of higher flow, as the rotation speed increases, the axial velocity is reduced and the position of the maximum axial velocity is skewed towards the centre of the annulus. There is a reduction of the swirl velocity corresponding to the rise of the volumetric flow rate.

  11. Aircraft Design

    NASA Technical Reports Server (NTRS)

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

    2016-01-01

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

  12. Vertical resolution and accuracy of atmospheric infrared sounding spectrometers

    NASA Technical Reports Server (NTRS)

    Huang, Hung-Lung; Smith, William L.; Woolf, Harold M.

    1992-01-01

    A theoretical analysis is performed to evaluate the accuracy and vertical resolution of atmospheric profiles obtained with the HIRS/2, GOES I/M, and HIS instruments. In addition, a linear simultaneous retrieval algorithm is used with aircraft observations to validate the theoretical predictions. Both theoretical and observational results clearly indicate that the accuracy and vertical resolution of the retrieval profile would be improved by high spectral resolution and broad spectral coverage of infrared radiance measurements. The HIS is found to possess the equivalent of 11 pieces of temperature- and 9 pieces of water vapor-independent precise measurements. The characteristics for temperature include a vertical resolution of 1-6 km with an accuracy of 1 K and for water vapor a vertical resolution of 0.5-3.0 km with an accuracy of 3 K in dewpoint temperature. The HIS is a factor of 2-3 times better in vertical resolution and a factor of 2 times better in accuracy than the GOES I/M and HIRS/2 filter radiometers.

  13. Vertically-resolved profiles of mass concentrations and particle backscatter coefficients of Asian dust plumes derived from lidar observations of silicon dioxide.

    PubMed

    Noh, Youngmin; Müller, Detlef; Shin, Sung-Kyun; Shin, Dongho; Kim, Young J

    2016-01-01

    This study presents a method to retrieve vertically-resolved profiles of dust mass concentrations by analyzing Raman lidar signals of silicon dioxide (quartz) at 546nm. The observed particle plumes consisted of mixtures of East Asian dust with anthropogenic pollution. Our method for the first time allows for extracting the contribution of the aerosol component "pure dust" contained in the aerosol type "polluted dust". We also propose a method that uses OPAC (Optical Properties of Aerosols and Clouds) and the mass concentrations profiles of dust in order to derive profiles of backscatter coefficients of pure dust in mixed dust/pollution plumes. The mass concentration of silicon dioxide (quartz) in the atmosphere can be estimated from the backscatter coefficient of quartz. The mass concentration of dust is estimated by the weight percentage (38-77%) of mineral quartz in Asian dust. The retrieved dust mass concentrations are classified into water soluble, nucleation, accumulation, mineral-transported and coarse mode according to OPAC. The mass mixing ratio of 0.018, 0.033, 0.747, 0.130 and 0.072, respectively, is used. Dust extinction coefficients at 550nm were calculated by using OPAC and prescribed number concentrations for each of the 5 components. Dust backscatter coefficients were calculated from the dust extinction coefficients on the basis of a lidar ratio of 45±3sr at 532nm. We present results of quartz-Raman measurements carried out on the campus of the Gwangju Institute of Science and Technology (35.10°N, 126.53°E) on 15, 16, and 21 March 2010.

  14. 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.

  15. Future V/STOL Aircraft For The Pacific Basin

    NASA Technical Reports Server (NTRS)

    Albers, James A.; Zuk, John

    1992-01-01

    Report describes geography and transportation needs of Asian Pacific region, and describes aircraft configurations suitable for region and compares performances. Examines applications of high-speed rotorcraft, vertical/short-takeoff-and-landing (V/STOL) aircraft, and short-takeoff-and landing (STOL) aircraft. Configurations benefit commerce, tourism, and development of resources.

  16. Quantifying Wintertime Aerosol Nitrate Formation Pathways and Their Vertical Profiles in the Great Lakes Region of North America by CMAQ Process Analysis and Hourly Observations

    NASA Astrophysics Data System (ADS)

    Kim, Y.; Spak, S.; Carmichael, G. R.; Riemer, N. S.; Baek, J.; Fontaine, A.; Janssen, M.; Kenski, D. M.

    2012-12-01

    In order to better understand wintertime episodes of elevated fine particle (PM2.5) in the Great Lakes region, a modeling analysis using the CMAQ air quality model was conducted for January-March 2009, a period where special surface based observations were conducted at a pair of urban and rural sites in Wisconsin. The episodes are found to be regional and are characterized by low wind speeds, near-freezing temperatures, and elevated levels of ammonium nitrate. Integrated process rate (IPR) analysis and integrated reaction rate analysis (IRR) in 12 km regional simulations with the Community Multiscale Air Quality model (CMAQ) are employed to quantify contributions to nitrate formation from all simulated processes, most importantly local chemical production and transport. Substantial vertical profiles are found for nitric acid, nitrate, and N2O5. The maximum concentrations of aerosol nitrate occur at the surface and decrease with altitude. Nitric acid is produced most efficiently 50-200m above the surface at night. Surface concentrations of aerosol nitrate are maintained by downward transport via vertical diffusion. Aerosol nitrate is predominantly removed by dry deposition. The aerosol production rate is significantly higher during episodes, and both daytime and nighttime (N2O5) chemical pathways are important contributors to elevated concentrations. Near the surface at Milwaukee, the daytime formation pathway for nitric acid is larger than the nighttime pathways, while in rural areas, the relative magnitudes are reversed. Across the region, the importance of the nighttime pathway increases with altitude. A spatial analysis highlights regional variability at the surface layer and ~90m above surface for the period February 4 thru February 10, which includes two PM2.5 episodes. The net aerosol chemistry process rates and concentrations show the evolution of regional PM build-up of aerosol nitrate and nitric acid.

  17. Documentation of Atmospheric Conditions During Observed Rising Aircraft Wakes

    NASA Technical Reports Server (NTRS)

    Zak, J. Allen; Rodgers, William G., Jr.

    1997-01-01

    Flight tests were conducted in the fall of 1995 off the coast of Wallops Island, Virginia in order to determine characteristics of wake vortices at flight altitudes. A NASA Wallops Flight Facility C130 aircraft equipped with smoke generators produced visible wakes at altitudes ranging from 775 to 2225 m in a variety of atmospheric conditions, orientations (head wind, cross wind), and airspeeds. Meteorological and aircraft parameters were collected continuously from a Langley Research Center OV-10A aircraft as it flew alongside and through the wake vortices at varying distances behind the C130. Meteorological data were also obtained from special balloon observations made at Wallops. Differential GPS capabilities were on each aircraft from which accurate altitude profiles were obtained. Vortices were observed to rise at distances beyond a mile behind the C130. The maximum altitude was 150 m above the C130 in a near neutral atmosphere with significant turbulence. This occurred from large vertical oscillations in the wakes. There were several cases when vortices did not descend after a very short initial period and remained near generation altitude in a variety of moderately stable atmospheres and wind shears.

  18. Vertical distribution and temporal changes of 137Cs in soil profiles under various land uses after the Fukushima Dai-ichi Nuclear Power Plant accident.

    PubMed

    Takahashi, Junko; Tamura, Kenji; Suda, Tomoya; Matsumura, Ryo; Onda, Yuichi

    2015-01-01

    We monitored the vertical distribution of (137)Cs in soil profiles under eight different land uses for the 2 y after the Fukushima Dai-ichi Nuclear Power Plant accident, and discussed the temporal changes in the early-stage of the migration and the determinants of the initial distribution. The soil samples were collected for four surveys using a scraper plate at each study site, which consisted of three forests (mixed forest, mature cedar, and young cedar), two grasslands (pasture and meadow) and three abandoned agricultural fields (farm land, tobacco field, and paddy field). The land use patterns have a large influence on some soil properties and the migration processes of (137)Cs above ground, resulting in different distribution of (137)Cs in those soil profiles. Specifically, the secondary deposition of (137)Cs from the coniferous canopy, retention of (137)Cs by litter layer, and the homogenization of (137)Cs concentrations in surface soil by natural soil mixing such as the disturbance by cattle grazing, roots growing and the formation of needle ice were important to cause redistribution of the deposited (137)Cs. Only in the paddy field, the (137)Cs inventory in subsurface soils (5-10 cm) gradually increased and comprised 26% of the total (137)Cs in 2 y, showing the downward migration of (137)Cs to subsurface soil. In the other sites, it was considered that (137)Cs were strongly adsorbed by soil particles and rarely migrated downward as soluble form. Vertical distributions during the first survey were able to be used as the initial distributions and were well fitted to the exponential equation. The distribution parameters α (relaxation depth) and β (relaxation mass depth), calculated by the exponential equation were correlated with RIP (r = -0.806, p < 0.05), macro pore (r = 0.651, p = 0.11), and dispersible fine particle content (r = 0.856, p < 0.05). It indicated that the initial distribution would be influenced by the Cs fixation ability of

  19. The influence of snow grain size and impurities on the vertical profiles of actinic flux and associated nitrogen oxide emissions on the Antarctic and Greenland ice sheets

    NASA Astrophysics Data System (ADS)

    Zatko, Maria C.

    We use observations of the absorption properties of black carbon and non-black-carbon impurities in near-surface snow collected near the research stations at South Pole and Dome C, Antarctica and Summit, Greenland combined with a snowpack actinic flux parameterization to estimate the vertical profile and e-folding depth of ultraviolet/near-visible (UV/near-vis) actinic flux in the snowpack at each location. We have developed a simple and broadly applicable parameterization to calculate the depth and wavelength dependent snowpack actinic flux that can be easily integrated into large scale (e.g. 3D) models of the atmosphere. The calculated e-folding depths of actinic flux at 305 nm, the peak wavelength of nitrate photolysis in the snowpack, are 8-12 cm near the stations and 15-31 cm away (> 11 km) from the stations. We find that the e-folding depth is strongly dependent on impurity content and wavelength in the UV/near-vis region, which explains the relatively shallow e-folding depths near stations where local activities lead to higher impurity levels. We calculate the lifetime of NOx in the snowpack interstitial air produced by photolysis of snowpack nitrate against escape (tau escape) from the snowpack via diffusion and wind pumping and compare this to the calculated lifetime of NOx against chemical conversion to HNO3 (tauchemical) to determine whether the NO x produced at a given depth can escape from the snowpack to the overlying atmosphere. Comparison of tauescape and tauchemical suggests efficient escape of photoproduced NOx in the snowpack to the overylying atmosphere. Calculated vertical actinic flux profiles and observed snowpack nitrate concentrations are used to determine the flux of NOx from the snowpack. Calculated NOx fluxes of 4.4x10 8-2.8x109 molecules cm-2 s-1 in remote polar locations and 3.2-8.2x108 molecules cm-2 s-1 near polar stations in January at Dome C and South Pole and in June at Summit suggest that NOx flux measurements near stations are

  20. Vertical profile, source apportionment, and toxicity of PAHs in sediment cores of a wharf near the coal-based steel refining industrial zone in Kaohsiung, Taiwan.

    PubMed

    Chen, Chih-Feng; Chen, Chiu-Wen; Ju, Yun-Ru; Dong, Cheng-Di

    2016-03-01

    Three sediment cores were collected from a wharf near a coal-based steel refining industrial zone in Kaohsiung, Taiwan. Analyses for 16 polycyclic aromatic hydrocarbons (PAHs) of the US Environmental Protection Agency priority list in the core sediment samples were conducted using gas chromatography-mass spectrometry. The vertical profiles of PAHs in the core sediments were assessed, possible sources and apportionment were identified, and the toxicity risk of the core sediments was determined. The results from the sediment analyses showed that total concentrations of the 16 PAHs varied from 11774 ± 4244 to 16755 ± 4593 ng/g dry weight (dw). Generally, the vertical profiles of the PAHs in the sediment cores exhibited a decreasing trend from the top to the lower levels of the S1 core and an increasing trend of PAHs from the top to the lower levels of the S2 and S3 cores. Among the core sediment samples, the five- and six-ring PAHs were predominantly in the S1 core, ranging from 42 to 54 %, whereas the composition of the PAHs in the S2 and S3 cores were distributed equally across three groups: two- and three-ring, four-ring, and five- and six-ring PAHs. The results indicated that PAH contamination at the site of the S1 core had a different source. The molecular indices and principal component analyses with multivariate linear regression were used to determine the source contributions, with the results showing that the contributions of coal, oil-related, and vehicle sources were 38.6, 35.9, and 25.5 %, respectively. A PAH toxicity assessment using the mean effect range-median quotient (m-ERM-q, 0.59-0.79), benzo[a]pyrene toxicity equivalent (TEQ(carc), 1466-1954 ng TEQ/g dw), and dioxin toxicity equivalent (TEQ(fish), 3036-4174 pg TEQ/g dw) identified the wharf as the most affected area. The results can be used for regular monitoring, and future pollution prevention and management should target the coal-based industries in this region for pollution reduction.

  1. Simulation of vertical profiles of stable water isotopes in a snow pit using a new offline isotopic snow-icecore model

    NASA Astrophysics Data System (ADS)

    Okazaki, A.; Yoshimura, K.; Takeuchi, N.; Fujita, K.; Aizen, V.; Oki, T.

    2012-04-01

    Given that ice cores consist of past snowfall in a chronologic and systematic order, we can utilize stable water isotope (SWI) information in ice cores to reconstruct the past climatic variations of temperature. Several modeling studies have tried to simulate the past SWI in precipitation preserved in ice cores (Werner and Heiman, 2002, Sjolte et al, 2011), but they are limited only on high latitude area. In such region, we do not have to consider post-depositional isotopic processes due to the extremely low temperature all over a year. However, when one wants to simulate the past SWI in ice cores in mid- and low-latitudinal areas, he has to consider the isotopic effects of the post-depositional processes because snow undergoes melt, sublimation and erosion by wind, by which SWI in snow are easily affected. Otherwise the reconstructed information of the past would be distorted and misleading. In this study, we developed a new off-line isotopic snow-icecore model: it simulates isotopic effects due to the post-depositional processes while precipitated snow is eventually transformed into an ice core. The model is based on the snow layer submodel of Iso-MATSIRO (Yoshimura et al., 2006) with a particular purpose to simulate a vertical profile of SWI at a glacier or ice sheet. Unlimited number of snow layers with a 20mm thickness increment is incorporated, whereas the original Iso-MATSIRO snow submodel has only three layers. The impact of wind erosion process, including blizzard, is also newly incorporated. Using this model forced with the output from IsoRSM (Yoshimura et al., 2010), i.e., an isotope enabled meso-scale climate model forced with historical meteorological reanalysis data, we simulated SWI in snow pits drilled at Belukha, Siberian Altai, which is close to ice core drilling site. The preliminary simulation period is for 2001-2003. Althouth the precipitation SWI simulated by IsoRSM alone does not correlate with the observed snow pit SWI, the SWI vertical

  2. The influence of snow grain size and impurities on the vertical profiles of actinic flux and associated NOx emissions on the Antarctic and Greenland ice sheets

    NASA Astrophysics Data System (ADS)

    Zatko, M. C.; Grenfell, T. C.; Alexander, B.; Doherty, S. J.; Thomas, J. L.; Yang, X.

    2013-04-01

    We use observations of the absorption properties of black carbon and non-black carbon impurities in near-surface snow collected near the research stations at South Pole and Dome C, Antarctica, and Summit, Greenland, combined with a snowpack actinic flux parameterization to estimate the vertical profile and e-folding depth of ultraviolet/near-visible (UV/near-vis) actinic flux in the snowpack at each location. We have developed a simple and broadly applicable parameterization to calculate depth and wavelength dependent snowpack actinic flux that can be easily integrated into large-scale (e.g., 3-D) models of the atmosphere. The calculated e-folding depths of actinic flux at 305 nm, the peak wavelength of nitrate photolysis in the snowpack, are 8-12 cm near the stations and 15-31 cm away (>11 km) from the stations. We find that the e-folding depth is strongly dependent on impurity content and wavelength in the UV/near-vis region, which explains the relatively shallow e-folding depths near stations where local activities lead to higher snow impurity levels. We calculate the lifetime of NOx in the snowpack interstitial air produced by photolysis of snowpack nitrate against wind pumping (τwind pumping) from the snowpack, and compare this to the calculated lifetime of NOx against chemical conversion to HNO3 (τchemical) to determine whether the NOx produced at a given depth can escape from the snowpack to the overlying atmosphere. Comparison of τwind pumping and τchemical suggests efficient escape of photoproduced NOx in the snowpack to the overlying atmosphere throughout most of the photochemically active zone. Calculated vertical actinic flux profiles and observed snowpack nitrate concentrations are used to estimate the potential flux of NOx from the snowpack. Calculated NOx fluxes of 4.4 × 108-3.8 × 109 molecules cm-2 s-1 in remote polar locations and 3.2-8.2 × 108 molecules cm-2 s-1 near polar stations for January at Dome C and South Pole and June at Summit

  3. The influence of snow grain size and impurities on the vertical profiles of actinic flux and associated NOx emissions on the Antarctic and Greenland ice sheets

    NASA Astrophysics Data System (ADS)

    Zatko, M. C.; Grenfell, T. C.; Alexander, B.; Doherty, S. J.; Thomas, J. L.; Yang, X.

    2012-06-01

    We use observations of the absorption properties of black carbon and non-black-carbon impurities in near-surface snow collected near the research stations at South Pole and Dome C, Antarctica and Summit, Greenland combined with a snowpack actinic flux parameterization to estimate the vertical profile and e-folding depth of ultraviolet/near-visible (UV/near-vis) actinic flux in the snowpack at each location. We have developed a simple and broadly applicable parameterization to calculate depth and wavelength dependent snowpack actinic flux that can be easily integrated into large scale (e.g. 3-D) models of the atmosphere. The calculated e-folding depths of actinic flux at 305 nm, the peak wavelength of nitrate photolysis in the snowpack, are 8-12 cm near the stations and 15-31 cm away (>11 km) from the stations. We find that the e-folding depth is strongly dependent on impurity content and wavelength in the UV/near-vis region, which explains the relatively shallow e-folding depths near stations where local activities lead to higher impurity levels. We calculate the lifetime of NOx in the snowpack interstitial air produced by photolysis of snowpack nitrate against escape (τescape) from the snowpack via diffusion and windpumping and compare this to the calculated lifetime of NOx against chemical conversion to HNO3 (τchemical) to determine whether the NOx produced at a given depth can escape from the snowpack to the overlying atmosphere. Comparison of τescape and τchemical suggests efficient escape of photoproduced NOx in the snowpack to the overlying atmosphere. Calculated vertical actinic flux profiles and observed snowpack nitrate concentrations are used to determine the flux of NOx from the snowpack. Calculated NOx fluxes of 4.4 × 108-2.8 × 109 molecules cm-2 s7-1 in remote polar locations and 3.2-8.2 × 108 molecules cm-2 s-1 near polar stations for January at Dome C and South Pole and June at Summit suggest that NOx flux measurements near stations are likely

  4. Vertical distribution and temporal changes of 137Cs in soil profiles under various land uses after the Fukushima Dai-ichi Nuclear Power Plant accident.

    PubMed

    Takahashi, Junko; Tamura, Kenji; Suda, Tomoya; Matsumura, Ryo; Onda, Yuichi

    2015-01-01

    We monitored the vertical distribution of (137)Cs in soil profiles under eight different land uses for the 2 y after the Fukushima Dai-ichi Nuclear Power Plant accident, and discussed the temporal changes in the early-stage of the migration and the determinants of the initial distribution. The soil samples were collected for four surveys using a scraper plate at each study site, which consisted of three forests (mixed forest, mature cedar, and young cedar), two grasslands (pasture and meadow) and three abandoned agricultural fields (farm land, tobacco field, and paddy field). The land use patterns have a large influence on some soil properties and the migration processes of (137)Cs above ground, resulting in different distribution of (137)Cs in those soil profiles. Specifically, the secondary deposition of (137)Cs from the coniferous canopy, retention of (137)Cs by litter layer, and the homogenization of (137)Cs concentrations in surface soil by natural soil mixing such as the disturbance by cattle grazing, roots growing and the formation of needle ice were important to cause redistribution of the deposited (137)Cs. Only in the paddy field, the (137)Cs inventory in subsurface soils (5-10 cm) gradually increased and comprised 26% of the total (137)Cs in 2 y, showing the downward migration of (137)Cs to subsurface soil. In the other sites, it was considered that (137)Cs were strongly adsorbed by soil particles and rarely migrated downward as soluble form. Vertical distributions during the first survey were able to be used as the initial distributions and were well fitted to the exponential equation. The distribution parameters α (relaxation depth) and β (relaxation mass depth), calculated by the exponential equation were correlated with RIP (r = -0.806, p < 0.05), macro pore (r = 0.651, p = 0.11), and dispersible fine particle content (r = 0.856, p < 0.05). It indicated that the initial distribution would be influenced by the Cs fixation ability of

  5. Analytic modeling of potential and threshold voltage for short-channel thin-body fully depleted silicon-on-insulator MOSFETs with a vertical Gaussian doping profile

    NASA Astrophysics Data System (ADS)

    Wei, Sufen; Zhang, Guohe; Shao, Zhibiao; Huang, Huixiang; Geng, Li

    2016-10-01

    We verify that one-dimensional (1D) Gaussian expression is an appropriate approximation of the vertical doping profile, which is obtained by combining perpendicular ion implantation and rapid thermal annealing (RTA), for short-channel thin-body (20-30 nm) fully depleted (FD) silicon-on-insulator (SOI) MOSFETs. The two-dimensional (2D) potential distribution of the silicon film is derived by adopting the evanescent mode analysis method, in which the potential function is broken into 1D long-channel and 2D short-channel potentials. The threshold voltage model is represented by the minimum front- and back-surface potentials of the silicon film. The application of the threshold voltage model can be extended to a 12 nm channel length. The results obtained using the models match well with the 2D numerical simulation results obtained using the Synopsys Sentaurus Device™. They provide a feasible way of developing new 2D models for nonuniform nanoscale thin-body FD-SOI devices.

  6. A vertical profile of PM10 dust concentrations measured during a regional dust event identified by MODIS Terra, western Queensland, Australia

    NASA Astrophysics Data System (ADS)

    McGowan, Hamish A.; Clark, Andrew

    2008-03-01

    Accurate determination of the spatiotemporal properties of dust plumes and their dust concentrations is essential for calibration of satellite products and the initialization and validation of numerical models that simulate the physical properties and affects of dust events. In this paper, we present a 500 m vertical profile of PM10 dust concentrations measured during a regional dust event in western Queensland, Australia. PM10 dust concentrations within the haze were found to be >20 times background ambient values and decreased with height following an exponential function. We apply an over-land algorithm to MODIS Terra satellite images of the dust haze to enhance its visual appearance against the bright land surface and define its size. In conjunction with the measured attenuation of dust concentrations with height we calculate the PM10 dust load of the plume to be ~60% of that which would have been calculated assuming a constant dust concentration up to the dust ceiling height. Results extend previous findings from tower-based studies made close to the surface and confirm that atmospheric dust concentrations decrease rapidly with increasing height, thereby enabling more accurate calculation of atmospheric dust loads during synoptic-scale dust outbreaks.

  7. Intercomparison of NO2 Slant Column Densities and Vertical Profiles Inferred from Balloon-borne Measurements of Solar Absorption Spectra in the IR and UV/vis

    NASA Astrophysics Data System (ADS)

    Butz, A.; Boesch, H.; Camy-Peyret, C.; Dorf, M.; Dufour, G.; Payan, S.; Weidner, F.; Pfeilsticker, K.

    2003-04-01

    During a series of LPMA/DOAS (Laboratoire de Physique Moléculaire et Applications/Differential Optical Absorption Spectroscopy) stratospheric balloon flights direct solar spectra in the UV/vis and near IR were simultaneously measured by the onboard installed Fourier Transform (LPMA) and two channel grating spectrometer (DOAS). The measurements were conducted in spring and summer at high and midlatitudes during ascent of the balloon into the stratosphere (30 - 40 km) and solar occultation at balloon float altitude. Here we present a direct intercomparison of the NO_2 slant column densities (SCDs) and vertical profiles retrieved from UV/vis-DOAS and IR-LPMA measurements for a wide range of geophysical conditions (ambient pressure and temperature and solar illumination). The comparison study thus allows us to verify the applied retrieval procedures, i.e., the underlying spectroscopic dataset as well as the inversion algorithms. First intercomparison studies showed a sizeable discrepancy between NO_2 inferred by LPMA in the IR and DOAS in the visible spectral range indicating deficiencies in the spectral retrieval techniques. After introducing a temperature correction scheme for the DOAS retrieval and a new LPMA MULTIFIT procedure which minimizes the correlations of the fitting parameters by performing the inversion simultaneously in several micro-windows, a reasonably good agreement between NO_2 inferred from both instruments is found.

  8. Estimating Mixing Heights Using Microwave Temperature Profiler

    NASA Technical Reports Server (NTRS)

    Nielson-Gammon, John; Powell, Christina; Mahoney, Michael; Angevine, Wayne

    2008-01-01

    A paper describes the Microwave Temperature Profiler (MTP) for making measurements of the planetary boundary layer thermal structure data necessary for air quality forecasting as the Mixing Layer (ML) height determines the volume in which daytime pollution is primarily concentrated. This is the first time that an airborne temperature profiler has been used to measure the mixing layer height. Normally, this is done using a radar wind profiler, which is both noisy and large. The MTP was deployed during the Texas 2000 Air Quality Study (TexAQS-2000). An objective technique was developed and tested for estimating the ML height from the MTP vertical temperature profiles. In order to calibrate the technique and evaluate the usefulness of this approach, estimates from a variety of measurements during the TexAQS-2000 were compared. Estimates of ML height were used from radiosondes, radar wind profilers, an aerosol backscatter lidar, and in-situ aircraft measurements in addition to those from the MTP.

  9. 48 CFR 1852.228-70 - Aircraft ground and flight risk.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Aircraft ground and flight... and Clauses 1852.228-70 Aircraft ground and flight risk. As prescribed in 1828.370(a), insert the..., vertical take-off aircraft, lighter-than-air airships, or other nonconventional types of aircraft,...

  10. 48 CFR 1852.228-70 - Aircraft ground and flight risk.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Aircraft ground and flight... and Clauses 1852.228-70 Aircraft ground and flight risk. As prescribed in 1828.370(a), insert the..., vertical take-off aircraft, lighter-than-air airships, or other nonconventional types of aircraft,...

  11. 48 CFR 1852.228-70 - Aircraft ground and flight risk.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Aircraft ground and flight... and Clauses 1852.228-70 Aircraft ground and flight risk. As prescribed in 1828.370(a), insert the..., vertical take-off aircraft, lighter-than-air airships, or other nonconventional types of aircraft,...

  12. Characteristics of vertical air motion in isolated convective clouds

    NASA Astrophysics Data System (ADS)

    Yang, Jing; Wang, Zhien; Heymsfield, Andrew J.; French, Jeffrey R.

    2016-08-01

    The vertical velocity and air mass flux in isolated convective clouds are statistically analyzed using aircraft in situ data collected from three field campaigns: High-Plains Cumulus (HiCu) conducted over the midlatitude High Plains, COnvective Precipitation Experiment (COPE) conducted in a midlatitude coastal area, and Ice in Clouds Experiment-Tropical (ICE-T) conducted over a tropical ocean. The results show that small-scale updrafts and downdrafts (< 500 m in diameter) are frequently observed in the three field campaigns, and they make important contributions to the total air mass flux. The probability density functions (PDFs) and profiles of the observed vertical velocity are provided. The PDFs are exponentially distributed. The updrafts generally strengthen with height. Relatively strong updrafts (> 20 m s-1) were sampled in COPE and ICE-T. The observed downdrafts are stronger in HiCu and COPE than in ICE-T. The PDFs of the air mass flux are exponentially distributed as well. The observed maximum air mass flux in updrafts is of the order 104 kg m-1 s-1. The observed air mass flux in the downdrafts is typically a few times smaller in magnitude than that in the updrafts. Since this study only deals with isolated convective clouds, and there are many limitations and sampling issues in aircraft in situ measurements, more observations are needed to better explore the vertical air motion in convective clouds.

  13. Ozone measurements along vertical transects in the Alps.

    PubMed

    Werner, H; Kirchner, M; Welzl, G; Hangartner, M

    1999-01-01

    To investigate the vertical profiles of air pollutants in the boundary layer, aircraft and balloon-born measurements and measurements using a cable car as an instrument platform have been performed in different parts of the Alps. This on-line monitoring of atmospheric pollutants requires expensive and sophisticated techniques. In order to control ambient air quality in remote regions, where no infrastructure like power supply is available, simple instruments are required. The objective of this study, which was coordinated and evaluated by the GSF-Forschungszentrum für Umwelt und Gesundheit was first, to investigate the vertical distribution of ozone in different parts of the Alps and secondly, in addition to continuous analyser measurements, to test monitoring by means of two types of passive samplers. The selection of these samplers - one for one week use and another one for two week application - was based on a passive sampler intercomparison done in a preliminary study one year earlier.

  14. Characterizing the vertical profile of aerosol particle extinction and linear depolarization over Southeast Asia and the Maritime Continent: The 2007-2009 view from CALIOP

    NASA Astrophysics Data System (ADS)

    Campbell, James R.; Reid, Jeffrey S.; Westphal, Douglas L.; Zhang, Jianglong; Tackett, Jason L.; Chew, Boon Ning; Welton, Ellsworth J.; Shimizu, Atsushi; Sugimoto, Nobuo; Aoki, Kazuma; Winker, David M.

    2013-03-01

    Vertical profiles of 0.532 μm aerosol particle extinction coefficient and linear volume depolarization ratio are described for Southeast Asia and the Maritime Continent. Quality-screened and cloud-cleared Version 3.01 Level 2 NASA Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) 5-km Aerosol Profile datasets are analyzed from 2007 to 2009. Numerical simulations from the U.S. Naval Aerosol Analysis and Predictive System (NAAPS), featuring two-dimensional variational assimilation of NASA Moderate Resolution Imaging Spectroradiometer and Multi-angle Imaging SpectroRadiometer quality-assured datasets, combined with regional ground-based lidar measurements, are considered for assessing CALIOP retrieval performance, identifying bias, and evaluating regional representativeness. CALIOP retrievals of aerosol particle extinction coefficient and aerosol optical depth (AOD) are high over land and low over open waters relative to NAAPS (0.412/0.312 over land for all data points inclusive, 0.310/0.235 when the per bin average is used and each is treated as single data points; 0.102/0.151 and 0.086/0.124, respectively, over ocean). Regional means, however, are very similar (0.180/0.193 for all data points and 0.155/0.159 when averaged per normalized bin), as the two factors offset one another. The land/ocean offset is investigated, and discrepancies attributed to interpretation of particle composition and a-priori assignment of the extinction-to-backscatter ratio (“lidar ratio”) necessary for retrieving the extinction coefficient from CALIOP signals. Over land, NAAPS indicates more dust present than CALIOP algorithms are identifying, indicating a likely assignment of a higher lidar ratio representative of more absorptive particles. NAAPS resolves more smoke over water than identified with CALIOP, indicating likely usage of a lidar ratio characteristic of less absorptive particles to be applied that biases low AOD there. Over open waters except within the Bay of

  15. Characterizing the Vertical Profile of Aerosol Particle Extinction and Linear Depolarization over Southeast Asia and the Maritime Continent: The 2007-2009 View from CALIOP

    NASA Technical Reports Server (NTRS)

    Campbell, James R.; Reid, Jeffrey S.; Westphal, Douglas L.; Zhang, Jianglong; Tackett, Jason L.; Chew, Boon Ning; Welton, Ellsworth J.; Shimizu, Atsushi; Sugimoto, Nobuo; Aoki, Kazuma; Winker, David M.

    2012-01-01

    Vertical profiles of 0.532 µm aerosol particle extinction coefficient and linear volume depolarization ratio are described for Southeast Asia and the Maritime Continent. Quality-screened and cloud-cleared Version 3.01 Level 2 NASA Cloud Aerosol Lidar with Orthogonal Polarization (CALIOP) 5-km Aerosol Profile datasets are analyzed from 2007 to 2009. Numerical simulations from the U.S. Naval Aerosol Analysis and Predictive System (NAAPS), featuring two-dimensional variational assimilation of NASA Moderate Resolution Imaging Spectroradiometer and Multi-angle Imaging Spectro- Radiometer quality-assured datasets, combined with regional ground-based lidar measurements, are considered for assessing CALIOP retrieval performance, identifying bias, and evaluating regional representativeness. CALIOP retrievals of aerosol particle extinction coefficient and aerosol optical depth (AOD) are high over land and low over open waters relative to NAAPS (0.412/0.312 over land for all data points inclusive, 0.310/0.235 when the per bin average is used and each is treated as single data points; 0.102/0.151 and 0.086/0.124, respectively, over ocean). Regional means, however, are very similar (0.180/0.193 for all data points and 0.155/0.159 when averaged per normalized bin), as the two factors offset one another. The land/ocean offset is investigated, and discrepancies attributed to interpretation of particle composition and a-priori assignment of the extinction-to-backscatter ratio ("lidar ratio") necessary for retrieving the extinction coefficient from CALIOP signals. Over land, NAAPS indicates more dust present than CALIOP algorithms are identifying, indicating a likely assignment of a higher lidar ratio representative of more absorptive particles. NAAPS resolvesmore smoke overwater than identified with CALIOP, indicating likely usage of a lidar ratio characteristic of less absorptive particles to be applied that biases low AOD there. Over open waters except within the Bay of Bengal

  16. Continental pollution in the western Mediterranean basin: vertical profiles of aerosol and trace gases measured over the sea during TRAQA 2012 and SAFMED 2013

    NASA Astrophysics Data System (ADS)

    Di Biagio, C.; Doppler, L.; Gaimoz, C.; Grand, N.; Ancellet, G.; Raut, J.-C.; Beekmann, M.; Borbon, A.; Sartelet, K.; Attié, J.-L.; Ravetta, F.; Formenti, P.

    2015-08-01

    In this study we present airborne observations of aerosol and trace gases obtained over the sea in the western Mediterranean basin during the TRAQA (TRansport and Air QuAlity) and SAFMED (Secondary Aerosol Formation in the MEDiterranean) campaigns in summer 2012 and 2013. A total of 23 vertical profiles were measured up to 5000 m above sea level over an extended area (40-45° N and 2° W-12° E) including the Gulf of Genoa, southern France, the Gulf of Lion, and the Spanish coast. During TRAQA and SAFMED the study area experienced a wide range of meteorological conditions which favoured pollution export from different sources located around the basin. Also, several events of dust outflows were measured during the campaigns. Observations from the present study show that continental pollution largely affects the western Mediterranean both close to coastal regions and in the open sea as far as ~ 250 km from the coastline. The measured aerosol scattering coefficient varies between ~ 20 and 120 Mm-1, while carbon monoxide (CO) and ozone (O3) mixing ratios are in the range of 60-165 and 30-85 ppbv, respectively. Pollution reaches 3000-4000 m in altitude and presents a very complex and highly stratified structure characterized by fresh and aged layers both in the boundary layer and in the free troposphere. Within pollution plumes the measured particle concentration in the Aitken (0.004-0.1 μm) and accumulation (0.1-1.0 μm) modes is between ~ 30 and 5000-6000 scm-3 (standard cm-3), which is comparable to the aerosol concentration measured in continental areas under pollution conditions. Additionally, our measurements indicate the presence of highly concentrated Aitken layers (10 000-15 000 scm-3) observed both close to the surface and in the free troposphere, possibly linked to the influence of new particle formation (NPF) episodes over the basin.

  17. Determination of precipitation profiles from airborne passive microwave radiometric measurements

    NASA Technical Reports Server (NTRS)

    Kummerow, Christian; Hakkarinen, Ida M.; Pierce, Harold F.; Weinman, James A.

    1991-01-01

    This study presents the first quantitative retrievals of vertical profiles of precipitation derived from multispectral passive microwave radiometry. Measurements of microwave brightness temperature (Tb) obtained by a NASA high-altitude research aircraft are related to profiles of rainfall rate through a multichannel piecewise-linear statistical regression procedure. Statistics for Tb are obtained from a set of cloud radiative models representing a wide variety of convective, stratiform, and anvil structures. The retrieval scheme itself determines which cloud model best fits the observed meteorological conditions. Retrieved rainfall rate profiles are converted to equivalent radar reflectivity for comparison with observed reflectivities from a ground-based research radar. Results for two case studies, a stratiform rain situation and an intense convective thunderstorm, show that the radiometrically derived profiles capture the major features of the observed vertical structure of hydrometer density.

  18. Aircraft cybernetics

    NASA Technical Reports Server (NTRS)

    1977-01-01

    The use of computers for aircraft control, flight simulation, and inertial navigation is explored. The man-machine relation problem in aviation is addressed. Simple and self-adapting autopilots are described and the assets and liabilities of digital navigation techniques are assessed.

  19. Dust layer profiling using an aerosol dropsonde

    NASA Astrophysics Data System (ADS)

    Ulanowski, Zbigniew; Kaye, Paul Henry; Hirst, Edwin; Wieser, Andreas; Stanley, Warren

    2015-04-01

    Routine meteorological data is obtained in the atmosphere using disposable radiosondes, giving temperature, pressure, humidity and wind speed. Additional measurements are obtained from dropsondes, released from research aircraft. However, a crucial property not yet measured is the size and concentration of atmospheric particulates, including dust. Instead, indirect measurements are employed, relying on remote sensing, to meet the demands from areas such as climate research, air quality monitoring, civil emergencies etc. In addition, research aircraft can be used in situ, but airborne measurements are expensive, and aircraft use is restricted to near-horizontal profiling, which can be a limitation, as phenomena such as long-range transport depend on the vertical distribution of aerosol. The Centre for Atmospheric and Instrumentation Research at University of Hertfordshire develops light-scattering instruments for the characterization of aerosols and cloud particles. Recently a range of low-cost, miniature particle counters has been created, intended for use with systems such as disposable balloon-borne radiosondes, dropsondes, or in dense ground-based sensor networks. Versions for different particle size ranges exist. They have been used for vertical profiling of aerosols such as mineral dust or volcanic ash. A disadvantage of optical particle counters that sample through a narrow inlet is that they can become blocked, which can happen in cloud, for example. Hence, a different counter version has been developed, which can have open-path geometry, as the sensing zone is defined optically rather than being delimited by the flow system. This counter has been used for ground based air-quality monitoring around Heathrow airport. The counter has also been adapted for use with radiosondes or dropsondes. The dropsonde version has been successfully tested by launching it from research aircraft together with the so-called KITsonde, developed at the Karlsruhe Institute of

  20. Retrieving the vertical distribution of chlorophyll a concentration and phytoplankton community composition from in situ fluorescence profiles: A method based on a neural network with potential for global-scale applications

    NASA Astrophysics Data System (ADS)

    Sauzède, R.; Claustre, H.; Jamet, C.; Uitz, J.; Ras, J.; Mignot, A.; D'Ortenzio, F.

    2015-01-01

    neural network-based method is developed to assess the vertical distribution of (1) chlorophyll a concentration ([Chl]) and (2) phytoplankton community size indices (i.e., microphytoplankton, nanophytoplankton, and picophytoplankton) from in situ vertical profiles of chlorophyll fluorescence. This method (FLAVOR for Fluorescence to Algal communities Vertical distribution in the Oceanic Realm) uses as input only the shape of the fluorescence profile associated with its acquisition date and geo-location. The neural network is trained and validated using a large database including 896 concomitant in situ vertical profiles of High-Performance Liquid Chromatography (HPLC) pigments and fluorescence. These profiles were collected during 22 oceanographic cruises representative of the global ocean in terms of trophic and oceanographic conditions, making our method applicable to most oceanic waters. FLAVOR is validated with respect to the retrieval of both [Chl] and phytoplankton size indices using an independent in situ data set and appears to be relatively robust spatially and temporally. To illustrate the potential of the method, we applied it to in situ measurements of the BATS (Bermuda Atlantic Time Series Study) site and produce monthly climatologies of [Chl] and associated phytoplankton size indices. The resulting climatologies appear very promising compared to climatologies based on available in situ HPLC data. With the increasing availability of spatially and temporally well-resolved data sets of chlorophyll fluorescence, one possible global-scale application of FLAVOR could be to develop 3-D and even 4-D climatologies of [Chl] and associated composition of phytoplankton communities. The Matlab and R codes of the proposed algorithm are provided as supporting information.

  1. Science requirements and feasibility/design studies of a very-high-altitude aircraft for atmospheric research

    NASA Technical Reports Server (NTRS)

    Russell, Philip B.; Lux, David P.; Reed, R. Dale; Loewenstein, Max; Wegener, Steven

    1991-01-01

    The advantages and shortcomings of currently available aircraft for use in very high altitude missions to study such problems as polar ozone or stratosphere-troposphere exchange pose the question of whether to develop advanced aircraft for atmospheric research. To answer this question, NASA conducted a workshop to determine science needs and feasibility/design studies to assess whether and how those needs could be met. It was determined that there was a need for an aircraft that could cruise at an altitude of 30 km with a range of 6,000 miles with vertical profiling down to 10 km and back at remote points and carry a payload of 3,000 lbs.

  2. Design definition study of a lift/cruise fan technology V/STOL aircraft. Volume 1: Navy operational aircraft

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Aircraft were designed and sized to meet Navy mission requirements. Five missions were established for evaluation: anti-submarine warfare (ASW), surface attack (SA), combat search and rescue (CSAR), surveillance (SURV), and vertical on-board delivery (VOD). All missions were performed with a short takeoff and a vertical landing. The aircraft were defined using existing J97-GE gas generators or reasonable growth derivatives in conjunction with turbotip fans reflecting LF460 type technology. The multipurpose aircraft configuration established for U.S. Navy missions utilizes the turbotip driven lift/cruise fan concept for V/STOL aircraft.

  3. Development and characterization of an aircraft aerosol time-of-flight mass spectrometer.

    PubMed

    Pratt, Kerri A; Mayer, Joseph E; Holecek, John C; Moffet, Ryan C; Sanchez, Rene O; Rebotier, Thomas P; Furutani, Hiroshi; Gonin, Marc; Fuhrer, Katrin; Su, Yongxuan; Guazzotti, Sergio; Prather, Kimberly A

    2009-03-01

    Vertical and horizontal profiles of atmospheric aerosols are necessary for understanding the impact of air pollution on regional and global climate. To gain further insight into the size-resolved chemistry of individual atmospheric particles, a smaller aerosol time-of-flight mass spectrometer (ATOFMS) with increased data acquisition capabilities was developed for aircraft-based studies. Compared to previous ATOFMS systems, the new instrument has a faster data acquisition rate with improved ion transmission and mass resolution, as well as reduced physical size and power consumption, all required advances for use in aircraft studies. In addition, real-time source apportionment software allows the immediate identification and classification of individual particles to guide sampling decisions while in the field. The aircraft (A)-ATOFMS was field-tested on the ground during the Study of Organic Aerosols in Riverside, CA (SOAR) and aboard an aircraft during the Ice in Clouds Experiment-Layer Clouds (ICE-L). Initial results from ICE-L represent the first reported aircraft-based single-particle dual-polarity mass spectrometry measurements and provide an increased understanding of particle mixing state as a function of altitude. Improved ion transmission allows for the first single-particle detection of species out to approximately m/z 2000, an important mass range for the detection of biological aerosols and oligomeric species. In addition, high time resolution measurements of single-particle mixing state are demonstrated and shown to be important for airborne studies where particle concentrations and chemistry vary rapidly.

  4. Characterization and validation of CH4 profiles derived from the GOSAT thermal infrared band

    NASA Astrophysics Data System (ADS)

    Tanaka, T.

    2015-12-01

    Methane (CH4) is one of most effective greenhouse gases which is responsible for global warming since pre-industrial time. CH4 emitted from anthropogenic and natural sources can be identified but poorly quantified in the local scale. Vertical profiles of CH4 are retrieved from the Greenhouse gases Observing SATellite (GOSAT) Thermal InfraRed (TIR) band, and the evaluation of the GOSAT TIR CH4 profile is being conducted. Here we show the results of the comparison of GOSAT TIR and the aircraft CH4 in-situ profiles measured by the National Oceanic and Atmospheric Administration (NOAA) and the Alpha Jet Atmospheric eXperiment (AJAX). We compare the TIR CH4 with the aircraft profiles from 15 NOAA sites and Railroad valley measured by AJAX. GOSAT TIR CH4 profiles are collected under conditions within 200 km and ±12 hours from the aircraft measurements at each observation site. The TIR CH4 profiles agree well with aircraft profiles and average differences have slightly negative biases (-3 to -6 ppb) in both the boundary layer and the free troposphere.Satellite based CH4 measurements can provide the large spatial and temporal that improve the understanding of CH4 transport, surface emissions and chemical loss.

  5. Aiding Vertical Guidance Understanding

    NASA Technical Reports Server (NTRS)

    Feary, Michael; McCrobie, Daniel; Alkin, Martin; Sherry, Lance; Polson, Peter; Palmer, Everett; McQuinn, Noreen

    1998-01-01

    A two-part study was conducted to evaluate modern flight deck automation and interfaces. In the first part, a survey was performed to validate the existence of automation surprises with current pilots. Results indicated that pilots were often surprised by the behavior of the automation. There were several surprises that were reported more frequently than others. An experimental study was then performed to evaluate (1) the reduction of automation surprises through training specifically for the vertical guidance logic, and (2) a new display that describes the flight guidance in terms of aircraft behaviors instead of control modes. The study was performed in a simulator that was used to run a complete flight with actual airline pilots. Three groups were used to evaluate the guidance display and training. In the training, condition, participants went through a training program for vertical guidance before flying the simulation. In the display condition, participants ran through the same training program and then flew the experimental scenario with the new Guidance-Flight Mode Annunciator (G-FMA). Results showed improved pilot performance when given training specifically for the vertical guidance logic and greater improvements when given the training and the new G-FMA. Using actual behavior of the avionics to design pilot training and FMA is feasible, and when the automated vertical guidance mode of the Flight Management System is engaged, the display of the guidance mode and targets yields improved pilot performance.

  6. An Exploratory Investigation of the Effects of a Thin Plastic Film Cover on the Profile Drag of an Aircraft Wing Panel

    NASA Technical Reports Server (NTRS)

    Beasley, W. D.; Mcghee, R. J.

    1977-01-01

    Exploratory wind tunnel tests were conducted on a large chord aircraft wing panel to evaluate the potential for drag reduction resulting from the application of a thin plastic film cover. The tests were conducted at a Mach number of 0.15 over a Reynolds number range from about 7 x 10 to the 6th power to 63 x 10 to the 6th power.

  7. Vertical Navigation Control Laws and Logic for the Next Generation Air Transportation System

    NASA Technical Reports Server (NTRS)

    Hueschen, Richard M.; Khong, Thuan H.

    2013-01-01

    A vertical navigation (VNAV) outer-loop control system was developed to capture and track the vertical path segments of energy-efficient trajectories that are being developed for high-density operations in the evolving Next Generation Air Transportation System (NextGen). The VNAV control system has a speed-on-elevator control mode to pitch the aircraft for tracking a calibrated airspeed (CAS) or Mach number profile and a path control mode for tracking the VNAV altitude profile. Mode control logic was developed for engagement of either the speed or path control modes. The control system will level the aircraft to prevent it from flying through a constraint altitude. A stability analysis was performed that showed that the gain and phase margins of the VNAV control system significantly exceeded the design gain and phase margins. The system performance was assessed using a six-deg-of-freedom non-linear transport aircraft simulation and the performance is illustrated with time-history plots of recorded simulation data.

  8. Vertical profiles of H2O, H2SO4, and sulfuric acid concentration at 45-75 km on Venus

    NASA Astrophysics Data System (ADS)

    Krasnopolsky, Vladimir A.

    2015-05-01

    A method developed by Krasnopolsky and Pollack (Krasnopolsky, V.A., Pollack, J.B. [1994]. Icarus 109, 58-78) to model vertical profiles of H2O and H2SO4 vapors and sulfuric acid concentration in the Venus cloud layer has been updated with improved thermodynamic parameters for H2O and H2SO4 and reduced photochemical production of sulfuric acid. The model is applied to the global-mean conditions and those at the low latitudes and at 60°. Variations in eddy diffusion near the lower cloud boundary are used to simulate variability in the cloud properties and abundances of H2O and H2SO4. The best version of the model for the global-mean condition results in a lower cloud boundary (LCB) at 47.5 km, H2SO4 peak abundance of 7.5 ppm at the LCB, and H2O mixing ratios of 7 ppm at 62 km and 3.5 ppm above 67 km. The model for low latitudes gives LCB at 48.5 km, the H2SO4 peak of 5 ppm, H2O of 8.5 ppm at 62 km and 3 ppm above 67 km. The model for 60° shows LCB at 46 km, the H2SO4 peak of 8.5 ppm, H2O of 9 ppm at 62 km and 4.5 ppm above 67 km. The calculated variability is induced by the proper changes in the production of sulfuric acid (by factors of 1.2 and 0.7 for the low latitudes and 60°, respectively) and reduction of eddy diffusion near 45 km relative to the value at 54 km by factors of 1.1, 3, and 4.5 for the low and middle (global-mean) latitudes and 60°, respectively. Concentration of sulfuric acid at the low and middle latitudes varies from ∼98% near 50 km to ∼80% at 60 km and then is almost constant at 79% at 70 km. Concentration at 60° is 98% at 50 km, 73% at 63 km, and 81% at 70 km. There is a reasonable agreement between the model results and observations except for the sulfuric acid concentration in the lower clouds. Variations of eddy diffusion in the lower cloud layer simulate variations in atmospheric dynamics and may induce strong variations in water vapor near the cloud tops. Variations in temperature may affect abundances of the H2O and H2SO4 vapors

  9. Continental pollution in the Western Mediterranean Basin: vertical profiles of aerosol and trace gases measured over the sea during TRAQA 2012 and SAFMED 2013

    NASA Astrophysics Data System (ADS)

    Di Biagio, C.; Doppler, L.; Gaimoz, C.; Grand, N.; Ancellet, G.; Raut, J.-C.; Beekmann, M.; Borbon, A.; Sartelet, K.; Attié, J.-L.; Ravetta, F.; Formenti, P.

    2015-03-01

    In this study we present airborne observations of aerosol and trace gases obtained over the sea in the Western Mediterranean Basin during the TRAQA (TRansport and Air QuAlity) and SAFMED (Secondary Aerosol Formation in the MEDiterranean) campaigns in summers 2012 and 2013. A total of 23 vertical profiles were measured up to 5000 m a.s.l. over an extended area (40-45° N latitude and 2° W-12° E longitude) including the Gulf of Genoa, Southern France, the Gulf of Lion, and the Spanish coast. TRAQA and SAFMED successfully measured a wide range of meteorological conditions which favoured the pollution export from different sources located around the basin. Also, several events of dust outflows were measured during the campaigns. Observations from the present study indicate that continental pollution largely affects the Western Mediterranean both close to coastal regions and in the open sea as far as ~250 km from the coastline. Aerosol layers not specifically linked with Saharan dust outflows are distributed ubiquitously which indicates quite elevated levels of background pollution throughout the Western Basin. The measured aerosol scattering coefficient varies between ~20 and 120 M m-1, while carbon monoxide (CO) and ozone (O3) mixing ratios are in the range of 60-170 and 30-85 ppbv, respectively. Pollution reaches 3000-4000 m in altitude and presents a very complex and highly stratified structure characterized by fresh and aged layers both in the boundary layer and in the free troposphere. Within pollution plumes the measured particle concentration in the Aitken (0.004-0.1 μm) and accumulation (0.1-1.0 μm) modes is between ˜ 100 and 5000-6000 s cm-3 (standard cm-3), which is comparable to the aerosol concentration measured in continental urban areas. Additionally, our measurements indicate the presence of highly concentrated Aitken layers (10 000-15 000 s cm-3) observed both close to the surface and in the free troposphere, possibly linked to the influence of new

  10. Holistic aerosol evaluation using synthesized aerosol aircraft measurements

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  11. Vertical Profiles Of {sup 226}Ra, {sup 232}Th And {sup 40}K Activities In Rocks From The Irati Formation Of The Parana Sedimentary Basin, Southern Brazil

    SciTech Connect

    Ferreira, Ademar de O.; Bastos, Rodrigo O.; Appoloni, Carlos R.

    2008-08-07

    Naturally occurring radioisotopes are present in different concentrations in sedimentary rocks, reflecting the origin of the sediments, the depositional environment, and more recent events such as weathering and erosion. Using a high-resolution {gamma}-ray spectrometry methodology, sedimentary rocks were measured to assess the concentration activities of the natural radioisotopes. The surveyed rocks are from the Irati formation in the Parana sedimentary basin, which are exposed by an abandoned, open-pit limestone mine, in the city of Sapopema, southern Brazil. The exposed vertical profile is 5 m, and its stratigraphy is represented by an alternation of limestone and bituminous shale (layers being a few decimeters thick), and some millimeter rhythm layers with limestone and bituminous shale laminas. Eleven samples were collected along this profile, each of them dried in the open air during 48 hours, sieved through 4 mm mesh and sealed in cylindrical recipients. Measurements were accomplished using a 66% relative efficiency HPGE detector connected to a standard gamma ray spectrometry electronic chain. The detector efficiency in the range of 60 to 1800 keV was carried out with the certified IAEA-385 sediment sample. The Lower Limit of Detection (LLD) to the system is 2.40 Bq{center_dot}kg{sup -1} for {sup 226}Ra, 1.84 Bq{center_dot}kg{sup -1} for {sup 232}Th and 4.20 Bq{center_dot}kg{sup -1} for {sup 40}K. Activity concentrations were determined for {sup 226}Ra (from 16.22 to 151.55 Bq{center_dot}kg{sup -1}), {sup 232}Th (from 2.93 to 56.12 Bq{center_dot}kg{sup -1}) and {sup 40}K (from 38.45 to 644.63 Bq{center_dot}kg{sup -1}). The layers enriched with organic matter presented the higher values of activity. The measured concentrations of the natural radioisotopes were lower for limestone samples (average values and respective deviations were 22.81{+-}0.22 Bq{center_dot}kg{sup -1} for {sup 226}Ra, 4.21{+-}0.07 Bq{center_dot}kg{sup -1} for {sup 232}Th, and 50

  12. Theoretical and numerical analysis of a soil organic matter decomposition model along vertical soil profiles and coupling the dynamics of carbon and nutrients dynamics.

    NASA Astrophysics Data System (ADS)

    Sainte-Marie, Julien; Barrandon, Matthieu; Saint-André, Laurent; Henrot, Antoine

    2014-05-01

    More than 250 models dedicated to the decomposition of the soil organic matter (SOM) were developed over the last thirty years. Among them, E. Bosatta & G. Ågren have proposed several equations based on the theory of organic matter quality noted q to describe heterogeneous SOM dynamics. These models are ruling the fate of carbon and nutrients concentrations in the soil organic matter. One of these models considers the decomposition of SOM along a vertical soil profile [1]. Carbon and nutrients distribution functions are noted ρc(q,z,t) and ρΞ(q,z,t) (g cm2 q-1) respectively where Ξ is a specific nutrient. The mass balance provides the following equations: δρc(q,z,t) u(q,z) δ« +∞ ' ' ' ' δ[ν(q,z)ρc(q,z,t)] δt = - fc e(q) ρc(q,z,t)+ fc 0 D (q,q )u(q,z)ρc(q ,z,t)dq- δz ,(1) δρ (q,z,t) u(q,z) δ« + ∞ δ [ν(q,z)ρ (q,z,t)] -Ξ--- = - fc--ρΞ(q,z,t)+ fΞ D(q,q')u(q',z)ρc(q',z,t)dq' ----Ξ--(2.) δt e(q) 0 δz where fc and fΞ are decomposer carbon and nutrient Ξ concentrations; u(q,z) (g gc-1 t-1) is the decomposer growth rate per unit of substrate carbon; e(q) is the decomposer efficiency; D(q,q') (q-1) is the dispersion function of quality; ν(q,z) (cmy-1) is the velocity of the particles of organic matter. This model considers continuous distributions in time, space and quality and requires few parameters describing soil physics and micro-biological activity. Despite these conceptual advantages, this particular approach was poorly used because of the absence of mathematical analysis. Therefore, Bosatta & Ågren have chosen to simplify the equations to obtain explicit solutions sufficient to describe a steady state. Here we extend their work from mathematical point of view. The existence and the uniqueness of solutions were proved for the original model. A numerical method was also implemented to simulate SOM dynamics. The consequences of model simplification were numerically studied by comparing the complete model versus the simplified one

  13. Aircraft-type dependency of contrail evolution

    NASA Astrophysics Data System (ADS)

    Unterstrasser, S.; Görsch, N.

    2014-12-01

    The impact of aircraft type on contrail evolution is assessed using a large eddy simulation model with Lagrangian ice microphysics. Six different aircraft ranging from the small regional airliner Bombardier CRJ to the largest aircraft Airbus A380 are taken into account. Differences in wake vortex properties and fuel flow lead to considerable variations in the early contrail geometric depth and ice crystal number. Larger aircraft produce contrails with more ice crystals (assuming that the number of initially generated ice crystals per kilogram fuel is constant). These initial differences are reduced in the first minutes, as the ice crystal loss during the vortex phase is stronger for larger aircraft. In supersaturated air, contrails of large aircraft are much deeper after 5 min than those of small aircraft. A parameterization for the final vertical displacement of the wake vortex system is provided, depending only on the initial vortex circulation and stratification. Cloud resolving simulations are used to examine whether the aircraft-induced initial differences have a long-lasting mark. These simulations suggest that the synoptic scenario controls the contrail cirrus evolution qualitatively. However, quantitative differences between the contrail cirrus properties of the various aircraft remain over the total simulation period of 6 h. The total extinctions of A380-produced contrails are about 1.5 to 2.5 times higher than those from contrails of a Bombardier CRJ.

  14. The design of sport and touring aircraft

    NASA Technical Reports Server (NTRS)

    Eppler, R.; Guenther, W.

    1984-01-01

    General considerations concerning the design of a new aircraft are discussed, taking into account the objective to develop an aircraft can satisfy economically a certain spectrum of tasks. Requirements related to the design of sport and touring aircraft included in the past mainly a high cruising speed and short take-off and landing runs. Additional requirements for new aircraft are now low fuel consumption and optimal efficiency. A computer program for the computation of flight performance makes it possible to vary automatically a number of parameters, such as flight altitude, wing area, and wing span. The appropriate design characteristics are to a large extent determined by the selection of the flight altitude. Three different wing profiles are compared. Potential improvements with respect to the performance of the aircraft and its efficiency are related to the use of fiber composites, the employment of better propeller profiles, more efficient engines, and the utilization of suitable instrumentation for optimal flight conduction.

  15. Horizontal Variability of Water and Its Relationship to Cloud Fraction near the Tropical Tropopause: Using Aircraft Observations of Water Vapor to Improve the Representation of Grid-scale Cloud Formation in GEOS-5

    NASA Technical Reports Server (NTRS)

    Selkirk, Henry B.; Molod, Andrea M.

    2014-01-01

    Large-scale models such as GEOS-5 typically calculate grid-scale fractional cloudiness through a PDF parameterization of the sub-gridscale distribution of specific humidity. The GEOS-5 moisture routine uses a simple rectangular PDF varying in height that follows a tanh profile. While below 10 km this profile is informed by moisture information from the AIRS instrument, there is relatively little empirical basis for the profile above that level. ATTREX provides an opportunity to refine the profile using estimates of the horizontal variability of measurements of water vapor, total water and ice particles from the Global Hawk aircraft at or near the tropopause. These measurements will be compared with estimates of large-scale cloud fraction from CALIPSO and lidar retrievals from the CPL on the aircraft. We will use the variability measurements to perform studies of the sensitivity of the GEOS-5 cloud-fraction to various modifications to the PDF shape and to its vertical profile.

  16. Improving the efficiency of smaller transport aircraft

    NASA Technical Reports Server (NTRS)

    Jones, R. T.

    1984-01-01

    Considered apart from its propulsive system the high altitude airplane itself adapted to higher flight altitudes than those in current use. Scaling on the assumption of constant aircraft density indicates that this conclusion applies most importantly to smaller transport aircraft. Climb to 60,000 ft could save time and energy for trips as short as 500 miles. A discussion of the effect of winglets on aircraft efficiency is presented. A 10% reduction of induced drag below that of a comparable elliptic wing can be achieved either by horizontal or vertical wing tip extensions.

  17. Crack detection on HU-25 Guardian aircraft

    SciTech Connect

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

    1996-10-01

    An ultrasonic inspection method was developed at FAA`s Airworthiness Assurance NDI Validation Center (AANC) to easily and rapidly detect hidden fatigue cracks in the copilot vertical windshield post on USCG (Coast Guard) HU-25 `Guardian` aircraft. The inspection procedure locates hidden cracks as small as 3.2 mm emanating from internal fastener holes and determines their length. A test procedure was developed and a baseline assessment of the USCG fleet conducted. Inspection results on 41 aircraft revealed good correlation with results made during subsequent structural disassembly and visual inspection of selected aircraft.

  18. Improving the efficiency of smaller transport aircraft

    SciTech Connect

    Jones, R.T.

    1984-07-01

    Considered apart from its propulsive system the high altitude airplane itself adapted to higher flight altitudes than those in current use. Scaling on the assumption of constant aircraft density indicates that this conclusion applies most importantly to smaller transport aircraft. Climb to 60,000 ft could save time and energy for trips as short as 500 miles. A discussion of the effect of winglets on aircraft efficiency is presented. A 10% reduction of induced drag below that of a comparable elliptic wing can be achieved either by horizontal or vertical wing tip extensions.

  19. High-altitude reconnaissance aircraft

    NASA Technical Reports Server (NTRS)

    Yazdi, Renee Anna

    1991-01-01

    At the equator the ozone layer ranges from 65,000 to 130,000+ ft, which is beyond the capabilities of the ER-2, NASA's current high-altitude reconnaissance aircraft. This project is geared to designing an aircraft that can study the ozone layer. The aircraft must be able to satisfy four mission profiles. The first is a polar mission that ranges from Chile to the South Pole and back to Chile, a total range of 6000 n.m. at 100,000 ft with a 2500-lb payload. The second mission is also a polar mission with a decreased altitude and an increased payload. For the third mission, the aircraft will take off at NASA Ames, cruise at 100,000 ft, and land in Chile. The final mission requires the aircraft to make an excursion to 120,000 ft. All four missions require that a subsonic Mach number be maintained because of constraints imposed by the air sampling equipment. Three aircraft configurations were determined to be the most suitable for meeting the requirements. The performance of each is analyzed to investigate the feasibility of the mission requirements.

  20. On The Vertical Speeds Of Airways Traffic

    NASA Astrophysics Data System (ADS)

    Magill, S. A. N.

    Knowledge of the statistics of aircraft vertical speeds is important both for the construction of realistic traffic simulators and for the development of trajectory prediction tools for use in future air traffic control (ATC) systems. This paper reports on the analysis of radar data recordings for nearly 10000 civil flights on airways. Results are presented for the means and spreads of vertical speeds as functions of altitude. Evidence is presented that roughly half of the observed spreads arise from fluctuations within each aircraft's trajectory, as opposed to variation from one aircraft to another. A simple procedure is proposed for simulating vertical speed data which has statistics similar to those obtained from the radar recordings. Some consequences of the results for the development of trajectory prediction tools for use in future ATC systems are discussed. The results suggest that the provision of accurate trajectory prediction tools is not as straightforward as it might at first appear to be.