WorldWideScience

Sample records for ground based 8m

  1. Ground based materials science experiments

    Science.gov (United States)

    Meyer, M. B.; Johnston, J. C.; Glasgow, T. K.

    1988-01-01

    The facilities at the Microgravity Materials Science Laboratory (MMSL) at the Lewis Research Center, created to offer immediate and low-cost access to ground-based testing facilities for industrial, academic, and government researchers, are described. The equipment in the MMSL falls into three categories: (1) devices which emulate some aspect of low gravitational forces, (2) specialized capabilities for 1-g development and refinement of microgravity experiments, and (3) functional duplicates of flight hardware. Equipment diagrams are included.

  2. Ground based materials science experiments

    Science.gov (United States)

    Meyer, M. B.; Johnston, J. C.; Glasgow, T. K.

    1988-01-01

    The facilities at the Microgravity Materials Science Laboratory (MMSL) at the Lewis Research Center, created to offer immediate and low-cost access to ground-based testing facilities for industrial, academic, and government researchers, are described. The equipment in the MMSL falls into three categories: (1) devices which emulate some aspect of low gravitational forces, (2) specialized capabilities for 1-g development and refinement of microgravity experiments, and (3) functional duplicates of flight hardware. Equipment diagrams are included.

  3. Space-based monitoring of ground deformation

    Science.gov (United States)

    Nobakht Ersi, Fereydoun; Safari, Abdolreza; Gamse, Sonja

    2016-07-01

    Ground deformation monitoring is valuable to understanding of the behaviour of natural phenomena. Space-Based measurement systems such as Global Positioning System are useful tools for continuous monitoring of ground deformation. Ground deformation analysis based on space geodetic techniques have provided a new, more accurate, and reliable source of information for geodetic positioning which is used to detect deformations of the Ground surface. This type of studies using displacement fields derived from repeated measurments of space-based geodetic networks indicates how crucial role the space geodetic methods play in geodynamics. The main scope of this contribution is to monitor of ground deformation by obtained measurements from GPS sites. We present ground deformation analysis in three steps: a global congruency test on daily coordinates of permanent GPS stations to specify in which epochs deformations occur, the localization of the deformed GPS sites and the determination of deformations.

  4. Ground-based observations of exoplanet atmospheres

    NARCIS (Netherlands)

    Mooij, Ernst Johan Walter de

    2011-01-01

    This thesis focuses on the properties of exoplanet atmospheres. The results for ground-based near-infrared secondary eclipse observations of three different exoplanets, TrES-3b, HAT-P-1b and WASP-33b, are presented which have been obtained with ground-based telescopes as part of the GROUSE project.

  5. Ground-based observations of exoplanet atmospheres

    NARCIS (Netherlands)

    Mooij, Ernst Johan Walter de

    2011-01-01

    This thesis focuses on the properties of exoplanet atmospheres. The results for ground-based near-infrared secondary eclipse observations of three different exoplanets, TrES-3b, HAT-P-1b and WASP-33b, are presented which have been obtained with ground-based telescopes as part of the GROUSE project.

  6. Fresnel zones for ground-based antennas

    DEFF Research Database (Denmark)

    Andersen, J. Bach

    1964-01-01

    The ordinary Fresnel zone concept is modified to include the influence of finite ground conductivity. This is important for ground-based antennas because the influence on the radiation pattern of irregularities near the antenna is determined by the amplitude and phase of the groundwave. A new...

  7. Illumination compensation in ground based hyperspectral imaging

    Science.gov (United States)

    Wendel, Alexander; Underwood, James

    2017-07-01

    Hyperspectral imaging has emerged as an important tool for analysing vegetation data in agricultural applications. Recently, low altitude and ground based hyperspectral imaging solutions have come to the fore, providing very high resolution data for mapping and studying large areas of crops in detail. However, these platforms introduce a unique set of challenges that need to be overcome to ensure consistent, accurate and timely acquisition of data. One particular problem is dealing with changes in environmental illumination while operating with natural light under cloud cover, which can have considerable effects on spectral shape. In the past this has been commonly achieved by imaging known reference targets at the time of data acquisition, direct measurement of irradiance, or atmospheric modelling. While capturing a reference panel continuously or very frequently allows accurate compensation for illumination changes, this is often not practical with ground based platforms, and impossible in aerial applications. This paper examines the use of an autonomous unmanned ground vehicle (UGV) to gather high resolution hyperspectral imaging data of crops under natural illumination. A process of illumination compensation is performed to extract the inherent reflectance properties of the crops, despite variable illumination. This work adapts a previously developed subspace model approach to reflectance and illumination recovery. Though tested on a ground vehicle in this paper, it is applicable to low altitude unmanned aerial hyperspectral imagery also. The method uses occasional observations of reference panel training data from within the same or other datasets, which enables a practical field protocol that minimises in-field manual labour. This paper tests the new approach, comparing it against traditional methods. Several illumination compensation protocols for high volume ground based data collection are presented based on the results. The findings in this paper are

  8. Ground based spectroscopy of hot Jupiters

    Science.gov (United States)

    Waldmann, Ingo

    2010-05-01

    It has been shown in recent years with great success that spectroscopy of exoplanetary atmospheres is feasible using space based observatories such as the HST and Spitzer. However, with the end of the Spitzer cold-phase, space based observations in the near to mid infra-red are limited, which will remain true until the the onset of the JWST. The importance of developing methods of ground based spectroscopic analysis of known hot Jupiters is therefore apparent. In the past, various groups have attempted exoplanetary spectroscopy using ground based facilities and various techniques. Here I will present results using a novel spectral retrieval method for near to mid infra-red emission and transmission spectra of exoplanetary atmospheres taken from the ground and discuss the feasibility of future ground-based spectroscopy in a broader context. My recently commenced PhD project is under the supervision of Giovanna Tinetti (University College London) and in collaboration with J. P. Beaulieu (Institut d'Astrophysique de Paris), Mark Swain and Pieter Deroo (Jet Propulsion Laboratory, Caltech).

  9. Calibration of Ground-based Lidar instrument

    DEFF Research Database (Denmark)

    Villanueva, Héctor; Gómez Arranz, Paula

    This report presents the result of the lidar calibration performed for the given Ground-based Lidar at DTU’s test site for large wind turbines at Høvsøre, Denmark. Calibration is here understood as the establishment of a relation between the reference wind speed measurements with measurement unce...

  10. Calibration of Ground -based Lidar instrument

    DEFF Research Database (Denmark)

    Villanueva, Héctor; Yordanova, Ginka

    This report presents the result of the lidar calibration performed for the given Ground-based Lidar at DTU’s test site for large wind turbines at Høvsøre, Denmark. Calibration is here understood as the establishment of a relation between the reference wind speed measurements with measurement unce...

  11. FGMOS Based Voltage-Controlled Grounded Resistor

    Directory of Open Access Journals (Sweden)

    R. Pandey

    2010-09-01

    Full Text Available This paper proposes a new floating gate MOSFET (FGMOS based voltage-controlled grounded resistor. In the proposed circuit FGMOS operating in the ohmic region is linearized by another conventional MOSFET operating in the saturation region. The major advantages of FGMOS based voltage-controlled grounded resistor (FGVCGR are simplicity, low total harmonic distortion (THD, and low power consumption. A simple application of this FGVCGR as a tunable high-pass filter is also suggested. The proposed circuits operate at the supply voltages of +/-0.75 V. The circuits are designed and simulated using SPICE in 0.25-µm CMOS technology. The simulation results of FGVCGR demonstrate a THD of 0.28% for the input signal 0.32 Vpp at 45 kHz, and a maximum power consumption of 254 µW.

  12. Space and Ground-Based Infrastructures

    Science.gov (United States)

    Weems, Jon; Zell, Martin

    This chapter deals first with the main characteristics of the space environment, outside and inside a spacecraft. Then the space and space-related (ground-based) infrastructures are described. The most important infrastructure is the International Space Station, which holds many European facilities (for instance the European Columbus Laboratory). Some of them, such as the Columbus External Payload Facility, are located outside the ISS to benefit from external space conditions. There is only one other example of orbital platforms, the Russian Foton/Bion Recoverable Orbital Capsule. In contrast, non-orbital weightless research platforms, although limited in experimental time, are more numerous: sounding rockets, parabolic flight aircraft, drop towers and high-altitude balloons. In addition to these facilities, there are a number of ground-based facilities and space simulators, for both life sciences (for instance: bed rest, clinostats) and physical sciences (for instance: magnetic compensation of gravity). Hypergravity can also be provided by human and non-human centrifuges.

  13. Development of Ground-Based Plant Sentinels

    Science.gov (United States)

    2007-11-02

    plants in response to different strains of Pseudomonas syringae. Planta . 217:767-775. De Moraes CM, Schultz JC, Mescher MC, Tumlinson JH. (2004...09-30-2004 Final Technical _ April 2001 - April 2003 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Developing Plants as Ground-based Sentinels 5b. GRANT...SUPPLEMENTARY NOTES 14. ABSTRACT 9 "Z Plants emit volatile mixes characteristic of exposure to both plant and animal (insect) pathogens (bacteria and fungi). The

  14. Enhanced H2 separation through mixed proton-electron conducting membranes based on La5.5 W0.8 M0.2 O11.25-δ.

    Science.gov (United States)

    Escolastico, Sonia; Seeger, Janka; Roitsch, Stefan; Ivanova, Mariya; Meulenberg, Wilhelm A; Serra, José M

    2013-08-01

    La(5.5) WO11.25-δ is a proton-conducting oxide that shows high protonic conductivity, sufficient electronic conductivity, and stability in moist CO2 environments. However, the H2 flows achieved to date when using La(5.5) WO11.25-δ membranes are still below the threshold for practical application in industrial processes. With the aim of improving the H2 flow obtained with this material, La(5.5) WO11.25-δ was doped in the W position by using Re and Mo; the chosen stoichiometry was La(5.5) W0.8 M0.2 O11.25-δ . This work presents the electrochemical characterization of these two compounds under reducing conditions, the H2 separation properties, as well as the influence of the H2 concentration in the feed stream, degree of humidification, and operating temperature. Doping with both Re and Mo enabled the magnitude of H2 permeation to be enhanced, reaching unrivaled values of up to 0.095 mL min(-1) cm(-2) at 700 °C for a La(5.5) W0.8 Re0.2 O11.25-δ membrane (760 μm thick). The spent membranes were investigated by using XRD, SEM, and TEM on focused-ion beam lamellas. Furthermore, the stability in CO2 -rich and H2 S-containing atmospheres was evaluated, and the compounds were shown to be stable in the atmospheres studied.

  15. Calibration of Ground-based Lidar instrument

    DEFF Research Database (Denmark)

    Yordanova, Ginka; Gómez Arranz, Paula

    This report presents the result of the lidar calibration performed for the given Ground-based Lidar at DTU’s test site for large wind turbines at Høvsøre, Denmark. Calibration is here understood as the establishment of a relation between the reference wind speed measurements with measurement...... uncertainties provided by measurement standard and corresponding lidar wind speed indications with associated measurement uncertainties. The lidar calibration concerns the 10 minute mean wind speed measurements. The comparison of the lidar measurements of the wind direction with that from wind vanes...

  16. Calibration of Ground-based Lidar instrument

    DEFF Research Database (Denmark)

    Yordanova, Ginka; Gómez Arranz, Paula

    This report presents the result of a test of a ground-based lidar of other type. The test was performed at DTU’s test site for large wind turbines at Høvsøre, Denmark. The result as an establishment of a relation between the reference wind speed measurements with measurement uncertainties provided...... by measurement standard and corresponding lidar wind speed indications with associated measurement uncertainties. The comparison of the lidar measurements of the wind direction with that from the wind vanes is also given....

  17. Calibration of Ground -based Lidar instrument

    DEFF Research Database (Denmark)

    Villanueva, Héctor; Yordanova, Ginka

    This report presents the result of the lidar calibration performed for the given Ground-based Lidar at DTU’s test site for large wind turbines at Høvsøre, Denmark. Calibration is here understood as the establishment of a relation between the reference wind speed measurements with measurement...... uncertainties provided by measurement standard and corresponding lidar wind speed indications with associated measurement uncertainties. The lidar calibration concerns the 10 minute mean wind speed measurements. The comparison of the lidar measurements of the wind direction with that from wind vanes...

  18. Calibration of Ground-based Lidar instrument

    DEFF Research Database (Denmark)

    Yordanova, Ginka; Gómez Arranz, Paula

    This report presents the result of the lidar calibration performed for the given Ground-based Lidar at DTU’s test site for large wind turbines at Høvsøre, Denmark. Calibration is here understood as the establishment of a relation between the reference wind speed measurements with measurement...... uncertainties provided by measurement standard and corresponding lidar wind speed indications with associated measurement uncertainties. The lidar calibration concerns the 10 minute mean wind speed measurements. The comparison of the lidar measurements of the wind direction with that from wind vanes...

  19. Calibration of Ground -based Lidar instrument

    DEFF Research Database (Denmark)

    Villanueva, Héctor; Georgieva Yankova, Ginka

    This report presents the result of the lidar calibration performed for the given Ground-based Lidar at DTU’s test site for large wind turbines at Høvsøre, Denmark. Calibration is here understood as the establishment of a relation between the reference wind speed measurements with measurement...... uncertainties provided by measurement standard and corresponding lidar wind speed indications with associated measurement uncertainties. The lidar calibration concerns the 10 minute mean wind speed measurements. The comparison of the lidar measurements of the wind direction with that from wind vanes...

  20. Ground-Based Observing Campaign of Briz-M Debris

    Science.gov (United States)

    Lederer, S. M.; Buckalew, B.; Frith, J.; Cowardin, H. M.; Hickson, P.; Matney, M.; Anz-Meador, P.

    2017-01-01

    In 2015, NASA's Orbital Debris Program Office (ODPO) completed the installation of the Meter Class Autonomous Telescope (MCAT) on Ascension Island. MCAT is a 1.3m optical telescope designed with a fast tracking capability for observing orbital debris at all orbital regimes (Low-Erath orbits to Geosyncronous (GEO) orbits) from a low latitude site. This new asset is dedicated year-round for debris observations, and its location fills a geographical gap in the Ground-based Electro Optical Space Surveillance (GEODSS) network. A commercial off the shelf (COTS) research grade 0.4m telescope (named the Benbrook telescope) will also be installed on Ascension at the end of 2016. This smaller version is controlled by the same master software, designed by Euclid Research, and can be tasked to work independently or in concert with MCAT. Like MCAT, it has a the same suite of filters, a similar field of view, and a fast-tracking Astelco mount, and is also capable of tracking debris at all orbital regimes. These assets are well suited for targeted campagins or surveys of debris. Since 2013, NASA's ODPO has also had extensive access to the 3.8m infrared UKIRT telescope, located on Mauna Kea. At nearly 14,000-ft, this site affords excellent conditions for collecting both photometery and spectroscopy at near-IR (0.9 - 2.5 micrometers SWIR) and thermal-IR (8 - 25 micrometers; LWIR) regimes, ideal for investigating material properties as well as thermal characteristics and sizes of debris. For the purposes of understanding orbital debris, taking data in both survey mode as well as targeting individual objects for more in-depth characterizations are desired. With the recent break-ups of Briz-M rocket bodies, we have collected a suite of data in the optical, near-infrared, and mid-infrared of in-tact objects as well as those classified as debris. A break-up at GEO of a Briz-M rocket occurred in January, 2016, well timed for the first remote observing survey-campaign with MCAT. Access to

  1. DYNAMIC SYSTEM ANALYSIS WITH pplane8.m (MATLAB® toolbox

    Directory of Open Access Journals (Sweden)

    Alejandro Regalado-Méndez

    2013-12-01

    Full Text Available In this work, four dynamic systems were analyzed (physical, chemical, ecological and economical, represented by autonomous systems of two ordinary differential equations. Main objective is proving that pplane8.m is an adequate and efficient computer tool. The analysis of autonomous systems was given by characterization of their critical points according to Coughanowr & LeBlanc (2009, with the MATLAB® toolbox pplane8.m. The main results are that pplane8.m (Polking, 2009 can quickly and precisely draw trajectories of each phase plane, it easily computes each critical point, and correctly characterize each equilibrium point of all autonomous studied systems. Finally, we can say that pplane8.m is a powerful tool to help the teaching-learning process for engineering students.

  2. Ground Based Investigation of Electrostatic Accelerometer in HUST

    Science.gov (United States)

    Bai, Y.; Zhou, Z.

    2013-12-01

    High-precision electrostatic accelerometers with six degrees of freedom (DOF) acceleration measurement were successfully used in CHAMP, GRACE and GOCE missions which to measure the Earth's gravity field. In our group, space inertial sensor based on the capacitance transducer and electrostatic control technique has been investigated for test of equivalence principle (TEPO), searching non-Newtonian force in micrometer range, and satellite Earth's field recovery. The significant techniques of capacitive position sensor with the noise level at 2×10-7pF/Hz1/2 and the μV/Hz1/2 level electrostatic actuator are carried out and all the six servo loop controls by using a discrete PID algorithm are realized in a FPGA device. For testing on ground, in order to compensate one g earth's gravity, the fiber torsion pendulum facility is adopt to measure the parameters of the electrostatic controlled inertial sensor such as the resolution, and the electrostatic stiffness, the cross couple between different DOFs. A short distance and a simple double capsule equipment the valid duration about 0.5 second is set up in our lab for the free fall tests of the engineering model which can directly verify the function of six DOF control. Meanwhile, high voltage suspension method is also realized and preliminary results show that the horizontal axis of acceleration noise is about 10-8m/s2/Hz1/2 level which limited mainly by the seismic noise. Reference: [1] Fen Gao, Ze-Bing Zhou, Jun Luo, Feasibility for Testing the Equivalence Principle with Optical Readout in Space, Chin. Phys. Lett. 28(8) (2011) 080401. [2] Z. Zhu, Z. B. Zhou, L. Cai, Y. Z. Bai, J. Luo, Electrostatic gravity gradiometer design for the advanced GOCE mission, Adv. Sp. Res. 51 (2013) 2269-2276. [3] Z B Zhou, L Liu, H B Tu, Y Z Bai, J Luo, Seismic noise limit for ground-based performance measurements of an inertial sensor using a torsion balance, Class. Quantum Grav. 27 (2010) 175012. [4] H B Tu, Y Z Bai, Z B Zhou, L Liu, L

  3. Current trends in ground based solar magnetometry

    Science.gov (United States)

    Gosain, Sanjay

    2016-07-01

    Continuous observations of the sun, over more than a century, have led to several important discoveries in solar astronomy. These include the discovery of the solar magnetism and its cyclic modulation, active region formation and decay and their role in energetic phenomena such as fares and coronal mass ejections (CMEs), fine structure and dynamics of the sunspots and small-scale organization of the magnetic flux in the form of flux tubes and so forth. In this article we give a brief overview of advancements in solar observational techniques in recent decades and the results obtained from the such observations. These include techniques to achieve high angular resolution, high spectral and polarimetric sensitivity and innovative new detectors. A wide range of spatial, temporal and spectral domains exploited by solar astronomers to understand the solar phenomena are discussed. Many new upcoming telescopes and instruments that are designed to address different aspects of solar physics problems are briefly described. Finally, we discuss the advantages of observing from the ground and how they can complement space-based observations.

  4. Ground-based observations of Kepler asteroseismic targets

    DEFF Research Database (Denmark)

    Uyttterhoeven , K.; Karoff, Christoffer

    2010-01-01

    We present the ground-based activities within the different working groups of the Kepler Asteroseismic Science Consortium (KASC). The activities aim at the systematic characterization of the 5000+ KASC targets, and at the collection of ground-based follow-up time-series data of selected promising...

  5. Power Gating Based Ground Bounce Noise Reduction

    Directory of Open Access Journals (Sweden)

    M. Uma Maheswari

    2014-08-01

    Full Text Available As low power circuits are most popular the decrease in supply voltage leads to increase in leakage power with respect to the technology scaling. So for removing this kind of leakages and to provide a better power efficiency many power gating techniques are used. But the leakage due to ground connection to the active part of the circuit is very high rather than all other leakages. As it is mainly due to the back EMF of the ground connection it was called it as ground bounce noise. To reduce this noise different methodologies are designed. In this paper the design of such an efficient technique related to ground bounce noise reduction using power gating circuits and comparing the results using DSCH and Microwind low power tools. In this paper the analysis of adders such as full adders using different types of power gated circuits using low power VLSI design techniques and to present the comparison results between different power gating methods.

  6. Movable Ground Based Recovery System for Reuseable Space Flight Hardware

    Science.gov (United States)

    Sarver, George L. (Inventor)

    2013-01-01

    A reusable space flight launch system is configured to eliminate complex descent and landing systems from the space flight hardware and move them to maneuverable ground based systems. Precision landing of the reusable space flight hardware is enabled using a simple, light weight aerodynamic device on board the flight hardware such as a parachute, and one or more translating ground based vehicles such as a hovercraft that include active speed, orientation and directional control. The ground based vehicle maneuvers itself into position beneath the descending flight hardware, matching its speed and direction and captures the flight hardware. The ground based vehicle will contain propulsion, command and GN&C functionality as well as space flight hardware landing cushioning and retaining hardware. The ground based vehicle propulsion system enables longitudinal and transverse maneuverability independent of its physical heading.

  7. Estimation of above ground biomass in boreal forest using ground-based Lidar

    Science.gov (United States)

    Taheriazad, L.; Moghadas, H.; Sanchez-Azofeifa, A.

    2017-05-01

    Assessing above ground biomass of forest is important for carbon storage monitoring in boreal forest. In this study, a new model is developed to estimate the above ground biomass using ground based Lidar data. 21 trees were measured and scanned across the plot area study in boreal forests of Alberta, Canada. The study area was scanned in the summer season 2014 to quantify the green biomass. The average of total crown biomass and green biomass in this study was 377 kg (standard deviation, S.D. = 243 kg) and 6.42 kg (S.D. = 2.69 m), respectively.

  8. ANÁLISIS DE SISTEMAS DINÁMICOS CON pplane8.m (MATLAB® toolbox)

    OpenAIRE

    Alejandro Regalado-Méndez; Jesús G. Madrid-González

    2013-01-01

    En este trabajo se analizaron cuatro sistemas dinámicos (físico, químico, ecológico y económico), los cuales son representados por sistemas autónomos de dos ecuaciones diferenciales ordinarias. El objetivo principal es demostrar que pplane8.m es una herramienta computacional adecuada y eficiente. El análisis de los sistemas autónomos se llevó a cabo con base en la caracterización de sus puntos críticos de acuerdo a lo citado por Coughanowr & LeBlanc (2009) y con ayuda de pplane8.m (MATLAB® to...

  9. A Quarter Active Suspension System Based Ground-Hook Controller

    OpenAIRE

    Turnip Arjon

    2016-01-01

    An alternative design technique for active suspension system of vehicle using a developved ground-hook damping system as a reference is proposed. The controller parameters are determined using Lyapunov method and can be tuned to precisely achieve the type of desired response which given by reference model. The simulation result show that the designed active suspension system based ground-hook reference model is able to significantly improve the ride comfort and the road holding compared with ...

  10. Precipitation in CF-8M duplex stainless steel welds

    Science.gov (United States)

    Ritter, Ann M.; Cieslak, Michael J.; Savage, Warren F.

    1983-01-01

    Welds of CF-8M, a cast 316-type stainless steel which normally solidifies as primary delta-ferrite, were induced to solidify as primary austenite by the addition of nitrogen to the shielding gas used during gas tungsten arc welding. Those welds which experienced a shift in solidification mode formed eutectic ferrite during the terminal transient stage of solidification. Primary delta-ferrite and eutectic ferrite are differentiated by their location in the dendritic microstructure. The shape of the ferrite/austenite interface tends to be rounded for primary delta-ferrite and more angular for eutectic ferrite. Elemental profiles were plotted from STEM/EDS measurements across the two types of ferrite, and showed differences between the composition of the austenite immediately adjacent to the primary delta-ferrite, as opposed to the eutectic ferrite. In addition, while the primary delta-ferrite/austenite interfaces are largely devoid of precipitation, the eutectic ferrite/austenite interfaces are densely covered with small precipitates of x-phase. The mean stoichiometry of this phase has been calculated from STEM/EDS data on extraction replicas, and approximates Fe50Cr32Mo13Ni5. Intragranular inclusions were also examined and found to be complex, with most of them containing varying quantities of Mn, Si, and S.

  11. Engineering uses of physics-based ground motion simulations

    Science.gov (United States)

    Baker, Jack W.; Luco, Nicolas; Abrahamson, Norman A.; Graves, Robert W.; Maechling, Phillip J.; Olsen, Kim B.

    2014-01-01

    This paper summarizes validation methodologies focused on enabling ground motion simulations to be used with confidence in engineering applications such as seismic hazard analysis and dynmaic analysis of structural and geotechnical systems. Numberical simullation of ground motion from large erthquakes, utilizing physics-based models of earthquake rupture and wave propagation, is an area of active research in the earth science community. Refinement and validatoin of these models require collaboration between earthquake scientists and engineering users, and testing/rating methodolgies for simulated ground motions to be used with confidence in engineering applications. This paper provides an introduction to this field and an overview of current research activities being coordinated by the Souther California Earthquake Center (SCEC). These activities are related both to advancing the science and computational infrastructure needed to produce ground motion simulations, as well as to engineering validation procedures. Current research areas and anticipated future achievements are also discussed.

  12. ANÁLISIS DE SISTEMAS DINÁMICOS CON pplane8.m (MATLAB® toolbox

    Directory of Open Access Journals (Sweden)

    Alejandro Regalado-Méndez

    2013-01-01

    Full Text Available En este trabajo se analizaron cuatro sistemas dinámicos (físico, químico, ecológico y económico, los cuales son representados por sistemas autónomos de dos ecuaciones diferenciales ordinarias. El objetivo principal es demostrar que pplane8.m es una herramienta computacional adecuada y eficiente. El análisis de los sistemas autónomos se llevó a cabo con base en la caracterización de sus puntos críticos de acuerdo a lo citado por Coughanowr & LeBlanc (2009 y con ayuda de pplane8.m (MATLAB® toolbox. Los principales resultados de este trabajo son que, pplane8.m (Polking, 2009 dibuja rápida y precisamente las trayectorias de todos los planos de fases, calcula con facilidad todos los puntos críticos y caracteriza correctamente cada uno de los puntos de equilibrio de los sistemas autónomos estudiados. Finalmente se puede decir que pplane8.m es una herramienta poderosa para ayudar en el proceso de enseñanza aprendizaje para estudiantes de un programa de ingeniería.

  13. Laser based bi-directional Gbit ground links with the Tesat transportable adaptive optical ground station

    Science.gov (United States)

    Heine, Frank; Saucke, Karen; Troendle, Daniel; Motzigemba, Matthias; Bischl, Hermann; Elser, Dominique; Marquardt, Christoph; Henninger, Hennes; Meyer, Rolf; Richter, Ines; Sodnik, Zoran

    2017-02-01

    Optical ground stations can be an alternative to radio frequency based transmit (forward) and receive (return) systems for data relay services and other applications including direct to earth optical communications from low earth orbit spacecrafts, deep space receivers, space based quantum key distribution systems and Tbps capacity feeder links to geostationary spacecrafts. The Tesat Transportable Adaptive Optical Ground Station is operational since September 2015 at the European Space Agency site in Tenerife, Spain.. This paper reports about the results of the 2016 experimental campaigns including the characterization of the optical channel from Tenerife for an optimized coding scheme, the performance of the T-AOGS under different atmospheric conditions and the first successful measurements of the suitability of the Alphasat LCT optical downlink performance for future continuous variable quantum key distribution systems.

  14. Ground point filtering of UAV-based photogrammetric point clouds

    Science.gov (United States)

    Anders, Niels; Seijmonsbergen, Arie; Masselink, Rens; Keesstra, Saskia

    2016-04-01

    Unmanned Aerial Vehicles (UAVs) have proved invaluable for generating high-resolution and multi-temporal imagery. Based on photographic surveys, 3D surface reconstructions can be derived photogrammetrically so producing point clouds, orthophotos and surface models. For geomorphological or ecological applications it may be necessary to separate ground points from vegetation points. Existing filtering methods are designed for point clouds derived using other methods, e.g. laser scanning. The purpose of this paper is to test three filtering algorithms for the extraction of ground points from point clouds derived from low-altitude aerial photography. Three subareas were selected from a single flight which represent different scenarios: 1) low relief, sparsely vegetated area, 2) low relief, moderately vegetated area, 3) medium relief and moderately vegetated area. The three filtering methods are used to classify ground points in different ways, based on 1) RGB color values from training samples, 2) TIN densification as implemented in LAStools, and 3) an iterative surface lowering algorithm. Ground points are then interpolated into a digital terrain model using inverse distance weighting. The results suggest that different landscapes require different filtering methods for optimal ground point extraction. While iterative surface lowering and TIN densification are fully automated, color-based classification require fine-tuning in order to optimize the filtering results. Finally, we conclude that filtering photogrammetric point clouds could provide a cheap alternative to laser scan surveys for creating digital terrain models in sparsely vegetated areas.

  15. Design Simulation and Optimization for the Flexible Displacement Support Structure Based on φ1.8 m Lightweight Reflector%φ1.8m轻质镜能动磨盘技术抛光的柔性限位支撑设计仿真与优化分析

    Institute of Scientific and Technical Information of China (English)

    钟显云; 范斌; 曾志革; 周家斌

    2012-01-01

    大口径轻质反射镜采用柔性支撑结构可以降低外界力载荷、惯性载荷及热载荷的负作用,从而保证光学系统的成像质量.为消除加工、检测与系统装调过程的定位误差,研究了应用于计算机控制能动磨盘加工(CCAL)技术抛光的柔性限位支撑模型.利用有限元分析软件(Ansys),分析φ1.8 m轻质镜采用柔性限位支撑时,CCAL技术抛光引起轻质镜的最大倾斜量、最大主应力以及主镜面变化范围,对支撑盘的口径及位置进行了优化设计,模拟仿真18点弹簧在不同压缩量下的镜面变形.仿真分析结果表明,柔性限位支撑的结构刚度、轻质镜底板倾斜量满足能动磨盘加工条件,最大主应力强度远小于主镜的许用应力,主镜面变形符合加工要求.%Large-diameter lightweight mirrors with a flexible support structure can reduce the external force loads, inertia loads, heat loads and so on to ensure the quality of the optical imaging system. In order to eliminate the positioning error during polishing, testing and installation process, a novel support technology named flexible displacement support model is used in CCAL polishing. Based on finite element analysis software Ansys, the greatest amount of tilt, the maximum principal stress and the deformation of j>\\. 8 m lightweight reflector caused by CCAL polishing based on the flexible displacement support are analyzed, the simulation and optimization of the diameter and distance of the restriction pad are finished, and the deformation of ^1.8 m lightweight reflector in different amounts of springs compression is simulated. Simulation results show that the stiffness of flexible support structure, amounts of tilt of reflector floor plate can meet the polishing condition, maximum principal stress intensity is much smaller than the yield stress of the primary mirror, and the deformation satisfies the processing requirements.

  16. GLAST and Ground-Based Gamma-Ray Astronomy

    Science.gov (United States)

    McEnery, Julie

    2008-01-01

    The launch of the Gamma-ray Large Area Space Telescope together with the advent of a new generation of ground-based gamma-ray detectors such as VERITAS, HESS, MAGIC and CANGAROO, will usher in a new era of high-energy gamma-ray astrophysics. GLAST and the ground based gamma-ray observatories will provide highly complementary capabilities for spectral, temporal and spatial studies of high energy gamma-ray sources. Joint observations will cover a huge energy range, from 20 MeV to over 20 TeV. The LAT will survey the entire sky every three hours, allowing it both to perform uniform, long-term monitoring of variable sources and to detect flaring sources promptly. Both functions complement the high-sensitivity pointed observations provided by ground-based detectors. Finally, the large field of view of GLAST will allow a study of gamma-ray emission on large angular scales and identify interesting regions of the sky for deeper studies at higher energies. In this poster, we will discuss the science returns that might result from joint GLAST/ground-based gamma-ray observations and illustrate them with detailed source simulations.

  17. GLAST and Ground-Based Gamma-Ray Astronomy

    Science.gov (United States)

    McEnery, Julie

    2008-01-01

    The launch of the Gamma-ray Large Area Space Telescope together with the advent of a new generation of ground-based gamma-ray detectors such as VERITAS, HESS, MAGIC and CANGAROO, will usher in a new era of high-energy gamma-ray astrophysics. GLAST and the ground based gamma-ray observatories will provide highly complementary capabilities for spectral, temporal and spatial studies of high energy gamma-ray sources. Joint observations will cover a huge energy range, from 20 MeV to over 20 TeV. The LAT will survey the entire sky every three hours, allowing it both to perform uniform, long-term monitoring of variable sources and to detect flaring sources promptly. Both functions complement the high-sensitivity pointed observations provided by ground-based detectors. Finally, the large field of view of GLAST will allow a study of gamma-ray emission on large angular scales and identify interesting regions of the sky for deeper studies at higher energies. In this poster, we will discuss the science returns that might result from joint GLAST/ground-based gamma-ray observations and illustrate them with detailed source simulations.

  18. A Quarter Active Suspension System Based Ground-Hook Controller

    Directory of Open Access Journals (Sweden)

    Turnip Arjon

    2016-01-01

    Full Text Available An alternative design technique for active suspension system of vehicle using a developved ground-hook damping system as a reference is proposed. The controller parameters are determined using Lyapunov method and can be tuned to precisely achieve the type of desired response which given by reference model. The simulation result show that the designed active suspension system based ground-hook reference model is able to significantly improve the ride comfort and the road holding compared with semi-active suspension.

  19. GEARS: An Enterprise Architecture Based On Common Ground Services

    Science.gov (United States)

    Petersen, S.

    2014-12-01

    Earth observation satellites collect a broad variety of data used in applications that range from weather forecasting to climate monitoring. Within NOAA the National Environmental Satellite Data and Information Service (NESDIS) supports these applications by operating satellites in both geosynchronous and polar orbits. Traditionally NESDIS has acquired and operated its satellites as stand-alone systems with their own command and control, mission management, processing, and distribution systems. As the volume, velocity, veracity, and variety of sensor data and products produced by these systems continues to increase, NESDIS is migrating to a new concept of operation in which it will operate and sustain the ground infrastructure as an integrated Enterprise. Based on a series of common ground services, the Ground Enterprise Architecture System (GEARS) approach promises greater agility, flexibility, and efficiency at reduced cost. This talk describes the new architecture and associated development activities, and presents the results of initial efforts to improve product processing and distribution.

  20. Integrated Train Ground Radio Communication System Based TD-LTE

    Institute of Scientific and Technical Information of China (English)

    ZHAO Hongli; CAO Yuan; ZHU Li; XU Wei

    2016-01-01

    In existing metro systems, the train ground radio communication system for different applications are deployed independently. Investing and constructing the communication infrastructures repeatedly wastes substan-tial social resources, and it brings difficulties to maintain all these infrastructures. We present the communication Quality of service (QoS) requirement for different train ground radio applications. An integrated TD-LTE based train ground radio communication system for the metro system (LTE-M) is designed next. In order to test the LTE-M system performance, an indoor testing environment is set up. The channel simulator and programmable attenua-tors are used to simulate the real metro environment. Ex-tensive test results show that the designed LTE-M system performance satisfies metro communication requirements.

  1. Ground-based observations of Kepler asteroseismic targets

    CERN Document Server

    Uytterhoeven, K; Southworth, J; Randall, S; Ostensen, R; Molenda-Zakowicz, J; Marconi, M; Kurtz, D W; Kiss, L; Gutierrez-Soto, J; Frandsen, S; De Cat, P; Bruntt, H; Briquet, M; Zhang, X B; Telting, J H; Steslicki, M; Ripepi, V; Pigulski, A; Paparo, M; Oreiro, R; Choong, Ngeow Chow; Niemczura, E; Nemec, J; Narwid, A; Mathias, P; Martin-Ruiz, S; Lehman, H; Kopacki, G; Karoff, C; Jackiewicz, J; Henden, A A; Handler, G; Grigachene, A; Green, E M; Garrido, R; Machado, L Fox; Debosscher, J; Creevey, O L; Catanzaro, G; Bognar, Z; Biazzo, K; Bernabei, S

    2010-01-01

    We present the ground-based activities within the different working groups of the Kepler Asteroseismic Science Consortium (KASC). The activities aim at the systematic characterization of the 5000+ KASC targets, and at the collection of ground-based follow-up time-series data of selected promising Kepler pulsators. So far, 35 different instruments at 30 telescopes on 22 different observatories in 12 countries are in use, and a total of more than 530 observing nights has been awarded. (Based on observations made with the Isaac Newton Telescope, William Herschel Telescope, Nordic Optical Telescope, Telescopio Nazionale Galileo, Mercator Telescope (La Palma, Spain), and IAC-80 (Tenerife, Spain). Also based on observations taken at the observatories of Sierra Nevada, San Pedro Martir, Vienna, Xinglong, Apache Point, Lulin, Tautenburg, Loiano, Serra la Nave, Asiago, McDonald, Skinakas, Pic du Midi, Mauna Kea, Steward Observatory, Bialkow Observatory of the Wroclaw University, Piszkesteto Mountain Station, Observato...

  2. Ground-Based Lidar for Atmospheric Boundary Layer Ozone Measurements

    Science.gov (United States)

    Kuang, Shi; Newchurch, Michael J.; Burris, John; Liu, Xiong

    2013-01-01

    Ground-based lidars are suitable for long-term ozone monitoring as a complement to satellite and ozonesonde measurements. However, current ground-based lidars are unable to consistently measure ozone below 500 m above ground level (AGL) due to both engineering issues and high retrieval sensitivity to various measurement errors. In this paper, we present our instrument design, retrieval techniques, and preliminary results that focus on the high-temporal profiling of ozone within the atmospheric boundary layer (ABL) achieved by the addition of an inexpensive and compact mini-receiver to the previous system. For the first time, to the best of our knowledge, the lowest, consistently achievable observation height has been extended down to 125 m AGL for a ground-based ozone lidar system. Both the analysis and preliminary measurements demonstrate that this lidar measures ozone with a precision generally better than 10% at a temporal resolution of 10 min and a vertical resolution from 150 m at the bottom of the ABL to 550 m at the top. A measurement example from summertime shows that inhomogeneous ozone aloft was affected by both surface emissions and the evolution of ABL structures.

  3. Ground-based lidar for atmospheric boundary layer ozone measurements.

    Science.gov (United States)

    Kuang, Shi; Newchurch, Michael J; Burris, John; Liu, Xiong

    2013-05-20

    Ground-based lidars are suitable for long-term ozone monitoring as a complement to satellite and ozonesonde measurements. However, current ground-based lidars are unable to consistently measure ozone below 500 m above ground level (AGL) due to both engineering issues and high retrieval sensitivity to various measurement errors. In this paper, we present our instrument design, retrieval techniques, and preliminary results that focus on the high-temporal profiling of ozone within the atmospheric boundary layer (ABL) achieved by the addition of an inexpensive and compact mini-receiver to the previous system. For the first time, to the best of our knowledge, the lowest, consistently achievable observation height has been extended down to 125 m AGL for a ground-based ozone lidar system. Both the analysis and preliminary measurements demonstrate that this lidar measures ozone with a precision generally better than ±10% at a temporal resolution of 10 min and a vertical resolution from 150 m at the bottom of the ABL to 550 m at the top. A measurement example from summertime shows that inhomogeneous ozone aloft was affected by both surface emissions and the evolution of ABL structures.

  4. Ground-Based Calibration Of A Microwave Landing System

    Science.gov (United States)

    Kiriazes, John J.; Scott, Marshall M., Jr.; Willis, Alfred D.; Erdogan, Temel; Reyes, Rolando

    1996-01-01

    System of microwave instrumentation and data-processing equipment developed to enable ground-based calibration of microwave scanning-beam landing system (MSBLS) at distances of about 500 to 1,000 ft from MSBLS transmitting antenna. Ensures accuracy of MSBLS near touchdown point, without having to resort to expense and complex logistics of aircraft-based testing. Modified versions prove useful in calibrating aircraft instrument landing systems.

  5. Ground-based Nuclear Detonation Detection (GNDD) Technology Roadmap

    Energy Technology Data Exchange (ETDEWEB)

    Casey, Leslie A.

    2014-01-13

    This GNDD Technology Roadmap is intended to provide guidance to potential researchers and help management define research priorities to achieve technology advancements for ground-based nuclear explosion monitoring science being pursued by the Ground-based Nuclear Detonation Detection (GNDD) Team within the Office of Nuclear Detonation Detection in the National Nuclear Security Administration (NNSA) of the U.S. Department of Energy (DOE). Four science-based elements were selected to encompass the entire scope of nuclear monitoring research and development (R&D) necessary to facilitate breakthrough scientific results, as well as deliver impactful products. Promising future R&D is delineated including dual use associated with the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Important research themes as well as associated metrics are identified along with a progression of accomplishments, represented by a selected bibliography, that are precursors to major improvements to nuclear explosion monitoring.

  6. Improving the atmospheric wind speed measured accuracy by the ground-based airglow imaging interferometer

    Science.gov (United States)

    Tang, Yuanhe; Yang, Rui; Gao, Haiyang; Zhai, Fengtao; Yu, Yang; Cui, Jin

    2017-02-01

    A prototype ground based airglow imaging interferometer (GBAII) has been constructed to observe the upper atmospheric wind velocity and temperature at an altitude of 90-100 km, but the GBAII's wind speed accuracy was found to be unsatisfactory with a value of 21.0 m/s. Three theoretical aspects have been investigated to improve the accuracy, with the following finding: 1) By replacing the surface coatings of the GBAII's 6 lenses and Michelson interferometer (MI) with a new wind-speed infrared film rather than the original visible light film, the accuracy can be increased by 3.0 m/s. 2) By replacing the original charge-coupled device (CCD) with a quantum efficiency (QE) of 0.38 at the wavelength of approximately 866 nm by an electron multiplying CCD (EMCCD) with QE of 0.95, the accuracy can be increased by 6.7 m/s. By adding all the factors that improve the accuracy of the GBAII, it can be improved by 15.0 m/s, which realizes the original aim of wind speed accuracy of 6.0 m/s. Experimental results have been obtained for two aspects: 1) By replacing the surface film on the GBAII's 6 lenses and MI interface, the wind speed accuracy has been increased by 3.8 m/s. 2) A new GBAII temperature controller has been constructed to control the environmental temperature in 0.2 K steps. The results obtained by the GBAII on Dec. 6, 2013 show an average atmospheric temperature of 206.5 K, zonal wind speed of -26.8 m/s and meridional wind speed of 28.1 m/s. These results are close to those of the TIMED (Thermosphere Ionosphere Mesosphere Energetics and Dynamics) satellite Doppler interferometer (TIDI) data collected at almost the same time.

  7. A comparative study of satellite and ground-based phenology.

    Science.gov (United States)

    Studer, S; Stöckli, R; Appenzeller, C; Vidale, P L

    2007-05-01

    Long time series of ground-based plant phenology, as well as more than two decades of satellite-derived phenological metrics, are currently available to assess the impacts of climate variability and trends on terrestrial vegetation. Traditional plant phenology provides very accurate information on individual plant species, but with limited spatial coverage. Satellite phenology allows monitoring of terrestrial vegetation on a global scale and provides an integrative view at the landscape level. Linking the strengths of both methodologies has high potential value for climate impact studies. We compared a multispecies index from ground-observed spring phases with two types (maximum slope and threshold approach) of satellite-derived start-of-season (SOS) metrics. We focus on Switzerland from 1982 to 2001 and show that temporal and spatial variability of the multispecies index correspond well with the satellite-derived metrics. All phenological metrics correlate with temperature anomalies as expected. The slope approach proved to deviate strongly from the temporal development of the ground observations as well as from the threshold-defined SOS satellite measure. The slope spring indicator is considered to indicate a different stage in vegetation development and is therefore less suited as a SOS parameter for comparative studies in relation to ground-observed phenology. Satellite-derived metrics are, however, very susceptible to snow cover, and it is suggested that this snow cover should be better accounted for by the use of newer satellite sensors.

  8. Ground-based complex for checking the optical system

    Science.gov (United States)

    Grebenyuk, V.; Boreiko, V.; Dmitrotsa, A.; Gorbunov, N.; Khrenov, B.; Klimov, P.; Lavrova, M.; Popescu, E. M.; Sabirov, B.; Tkachenko, A.; Tkachev, L.; Volvach, A.; Yashin, I.

    2016-09-01

    The purpose TUS space experiment is to study cosmic rays of ultrahigh energies produced by extensive air showers from space. The concentrator is located on satellite, made in the form of the Fresnel mirror towards the earth's atmosphere, the focus of which is a photodetector. The angle of view of the mirror is ±4.5° that for a given height of the orbit corresponds to the area 80 × 80 km2 on ground. The ground complex consisting of a number of stations, to check the optical system of the experiment is created, (their location and the amount will be determined after the launch of the satellite based on its actual orbit).

  9. Ground extraction from airborne laser data based on wavelet analysis

    Science.gov (United States)

    Xu, Liang; Yang, Yan; Jiang, Bowen; Li, Jia

    2007-11-01

    With the advantages of high resolution and accuracy, airborne laser scanning data are widely used in topographic mapping. In order to generate a DTM, measurements from object features such as buildings, vehicles and vegetation have to be classified and removed. However, the automatic extraction of bare earth from point clouds acquired by airborne laser scanning equipment remains a problem in LIDAR data filtering nowadays. In this paper, a filter algorithm based on wavelet analysis is proposed. Relying on the capability of detecting discontinuities of continuous wavelet transform and the feature of multi-resolution analysis, the object points can be removed, while ground data are preserved. In order to evaluate the performance of this approach, we applied it to the data set used in the ISPRS filter test in 2003. 15 samples have been tested by the proposed approach. Results showed that it filtered most of the objects like vegetation and buildings, and extracted a well defined ground model.

  10. Paper Productivity of Ground-based Large Optical Telescopes from 2000 to 2009

    CERN Document Server

    KIM, Sang Chul

    2011-01-01

    We present an analysis of the scientific ("refereed") paper productivity of the current largest (diameter >8 m) ground-based optical(-infrared) telescopes during the ten year period from 2000 to 2009. The telescopes for which we have gathered and analysed the scientific publication data are the two 10 m Keck telescopes, the four 8.2 m Very Large Telescopes (VLT), the two 8.1 m Gemini telescopes, the 8.2 m Subaru telescope, and the 9.2 m Hobby-Eberly Telescope (HET). We have analysed the rate of papers published in various astronomical journals produced by using these telescopes. While the total numbers of papers from these observatories are largest for the VLT followed by Keck, Gemini, Subaru, and HET, the number of papers produced by each component of the telescopes are largest for Keck followed by VLT, Subaru, Gemini, and HET. In 2009, each telescope of the Keck, VLT, Gemini, Subaru, and HET observatories produced 135, 109, 93, 107, and 5 refereed papers, respectively. We have shown that each telescope of t...

  11. Augmenting WFIRST Microlensing with a Ground-Based Telescope Network

    Science.gov (United States)

    Zhu, Wei; Gould, Andrew

    2016-06-01

    Augmenting the Wide Field Infrared Survey Telescope (WFIRST) microlensing campaigns with intensive observations from a ground-based network of wide-field survey telescopes would have several major advantages. First, it would enable full two-dimensional (2-D) vector microlens parallax measurements for a substantial fraction of low-mass lenses as well as planetary and binary events that show caustic crossing features. For a significant fraction of the free-floating planet (FFP) events and all caustic-crossing planetary/binary events, these 2-D parallax measurements directly lead to complete solutions (mass, distance, transverse velocity) of the lens object (or lens system). For even more events, the complementary ground-based observations will yield 1-D parallax measurements. Together with the 1-D parallaxes from WFIRST alone, they can probe the entire mass range M > M_Earth. For luminous lenses, such 1-D parallax measurements can be promoted to complete solutions (mass, distance, transverse velocity) by high-resolution imaging. This would provide crucial information not only about the hosts of planets and other lenses, but also enable a much more precise Galactic model. Other benefits of such a survey include improved understanding of binaries (particularly with low mass primaries), and sensitivity to distant ice-giant and gas-giant companions of WFIRST lenses that cannot be detected by WFIRST itself due to its restricted observing windows. Existing ground-based microlensing surveys can be employed if WFIRST is pointed at lower-extinction fields than is currently envisaged. This would come at some cost to the event rate. Therefore the benefits of improved characterization of lenses must be weighed against these costs.

  12. The STACEE-32 Ground Based Gamma-ray Detector

    CERN Document Server

    Hanna, D S; Boone, L M; Chantell, M C; Conner, Z; Covault, C E; Dragovan, M; Fortin, P; Gregorich, D T; Hinton, J A; Mukherjee, R; Ong, R A; Oser, S; Ragan, K; Scalzo, R A; Schütte, D R; Theoret, C G; Tümer, T O; Williams, D A; Zweerink, J A

    2002-01-01

    We describe the design and performance of the Solar Tower Atmospheric Cherenkov Effect Experiment detector in its initial configuration (STACEE-32). STACEE is a new ground-based gamma ray detector using the atmospheric Cherenkov technique. In STACEE, the heliostats of a solar energy research array are used to collect and focus the Cherenkov photons produced in gamma-ray induced air showers. The large Cherenkov photon collection area of STACEE results in a gamma-ray energy threshold below that of previous detectors.

  13. The STACEE Ground-Based Gamma-Ray Detector

    CERN Document Server

    Gingrich, D M; Bramel, D; Carson, J; Covault, C E; Fortin, P; Hanna, D S; Hinton, J A; Jarvis, A; Kildea, J; Lindner, T; Müller, C; Mukherjee, R; Ong, R A; Ragan, K; Scalzo, R A; Theoret, C G; Williams, D A; Zweerink, J A

    2005-01-01

    We describe the design and performance of the Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE) in its complete configuration. STACEE uses the heliostats of a solar energy research facility to collect and focus the Cherenkov photons produced in gamma-ray induced air showers. The light is concentrated onto an array of photomultiplier tubes located near the top of a tower. The large Cherenkov photon collection area of STACEE results in a gamma-ray energy threshold below that of previous ground-based detectors. STACEE is being used to observe pulsars, supernova remnants, active galactic nuclei, and gamma-ray bursts.

  14. Research on target accuracy for ground-based lidar

    Science.gov (United States)

    Zhu, Ling; Shi, Ruoming

    2009-05-01

    In ground based Lidar system, the targets are used in the process of registration, georeferencing for point cloud, and also can be used as check points. Generally, the accuracy of capturing the flat target center is influenced by scanning range and scanning angle. In this research, the experiments are designed to extract accuracy index of the target center with 0-90°scan angles and 100-195 meter scan ranges using a Leica HDS3000 laser scanner. The data of the experiments are listed in detail and the related results are analyzed.

  15. Ground-Based Global Positioning System (GPS) Meteorology Integrated Precipitable Water Vapor (IPW)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Ground-Based Global Positioning System (GPS) Meteorology Integrated Precipitable Water Vapor (IPW) data set measures atmospheric water vapor using ground-based...

  16. Applications of FBG-based sensors to ground stability monitoring

    Institute of Scientific and Technical Information of China (English)

    An-Bin Huang; Chien-Chih Wang; Jui-Ting Lee; Yen-Te Ho

    2016-01-01

    Over the past few decades, many optical fiber sensing techniques have been developed. Among these available sensing methods, optical fiber Bragg grating (FBG) is probably the most popular one. With its unique capabilities, FBG-based geotechnical sensors can be used as a sensor array for distributive (profile) measurements, deployed under water (submersible), for localized high resolution and/or dif-ferential measurements. The authors have developed a series of FBG-based transducers that include inclination, linear displacement and gauge/differential pore pressure sensors. Techniques that involve the field deployment of FBG inclination, extension and pore-pressure sensor arrays for automated slope stability and ground subsidence monitoring have been developed. The paper provides a background of FBG and the design concepts behind the FBG-based field monitoring sensors. Cases of field monitoring using the FBG sensor arrays are presented, and their practical implications are discussed.

  17. Statistical Studies of Ground-Based Optical Lightning Signatures

    Science.gov (United States)

    Hunt, C. R.; Nemzek, R. J.; Suszcynsky, D. M.

    2005-12-01

    Most extensive optical studies of lightning have been conducted from orbit, and the statistics of events collected from earth are relatively poorly documented. The time signatures of optical power measured in the presence of clouds are inevitably affected by scattering,which can distort the signatures by extending and delaying the amplitude profile in time. We have deployed two all-sky photodiode detectors, one in New Mexico and one in Oklahoma, which are gathering data alongside electric field change monitors as part of the LANL EDOTX Great Plains Array. Preliminary results show that the photodiode is sensitive to approximately 50% or more of RF events detected at ranges of up to 30 km, and still has some sensitivity at ranges in excess of 60 km (distances determined by the EDOTX field-change array). The shapes of events within this range were assessed, with focus on rise time, width, peak power, and their correlation to corresponding electric field signatures, and these are being compared with published on-orbit and ground-based data. Initial findings suggest a mean characteristic width (ratio of total detected optical energy to peak power) of 291 +/- 12 microseconds and a mean delay between the RF signal peak and optical peak of 121 +/- 17 microseconds. These values fall between prior ground-based measurements of direct return stroke emissions, and scattering-dominated on-orbit measurements. This work will promote better understanding of the correspondence between radio and optical measurements of lightning.

  18. Real-time Gaussian Markov random-field-based ground tracking for ground penetrating radar data

    Science.gov (United States)

    Bradbury, Kyle; Torrione, Peter A.; Collins, Leslie

    2009-05-01

    Current ground penetrating radar algorithms for landmine detection require accurate estimates of the location of the air/ground interface to maintain high levels of performance. However, the presence of surface clutter, natural soil roughness, and antenna motion lead to uncertainty in these estimates. Previous work on improving estimates of the location of the air/ground interface have focused on one-dimensional filtering techniques to localize the air/ground interface. In this work, we propose an algorithm for interface localization using a 2- D Gaussian Markov random field (GMRF). The GMRF provides a statistical model of the surface structure, which enables the application of statistical optimization techniques. In this work, the ground location is inferred using iterated conditional modes (ICM) optimization which maximizes the conditional pseudo-likelihood of the GMRF at a point, conditioned on its neighbors. To illustrate the efficacy of the proposed interface localization approach, pre-screener performance with and without the proposed ground localization algorithm is compared. We show that accurate localization of the air/ground interface provides the potential for future performance improvements.

  19. Identification of rainy periods from ground based microwave radiometry

    Directory of Open Access Journals (Sweden)

    Ada Vittoria Bosisio

    2012-03-01

    Full Text Available In this paper the authors present the results of a study aiming at detecting rainy data in measurements collected by a dual band ground-based radiometer. The proposed criterion is based on the ratio of the brightness temperatures observed in the 20-30 GHz band without need of any ancillary information. A major result obtained from the probability density of the ratio computed over one month of data is the identification of threshold values between clear sky, cloudy sky and rainy sky, respectively. A linear fit performed by using radiometric data and concurrent rain gauge measurements shows a correlation coefficient equal to 0.56 between the temperature ratio and the observed precipitation.

  20. Unique cell culture systems for ground based research

    Science.gov (United States)

    Lewis, Marian L.

    1990-01-01

    The horizontally rotating fluid-filled, membrane oxygenated bioreactors developed at NASA Johnson for spacecraft applications provide a powerful tool for ground-based research. Three-dimensional aggregates formed by cells cultured on microcarrier beads are useful for study of cell-cell interactions and tissue development. By comparing electron micrographs of plant seedlings germinated during Shuttle flight 61-C and in an earth-based rotating bioreactor it is shown that some effects of microgravity are mimicked. Bioreactors used in the UAH Bioreactor Laboratory will make it possible to determine some of the effects of altered gravity at the cellular level. Bioreactors can be valuable for performing critical, preliminary-to-spaceflight experiments as well as medical investigations such as in vitro tumor cell growth and chemotherapeutic drug response; the enrichment of stem cells from bone marrow; and the effect of altered gravity on bone and muscle cell growth and function and immune response depression.

  1. Spatial-angular modeling of ground-based biaxial lidar

    Science.gov (United States)

    Agishev, Ravil R.

    1997-10-01

    Results of spatial-angular LIDAR modeling based on an efficiency criterion introduced are represented. Their analysis shows that a low spatial-angular efficiency of traditional VIS and NIR systems is a main cause of a low S/BR ratio at the photodetector input. It determines the considerable measurements errors and the following low accuracy of atmospheric optical parameters retrieval. As we have shown, the most effective protection against intensive sky background radiation for ground-based biaxial LIDAR's consist in forming of their angular field according to spatial-angular efficiency criterion G. Some effective approaches to high G-parameter value achievement to achieve the receiving system optimization are discussed.

  2. DDCC-Based Quadrature Oscillator with Grounded Capacitors and Resistors

    Directory of Open Access Journals (Sweden)

    Montree Kumngern

    2009-01-01

    Full Text Available A new voltage-mode quadrature oscillator using two differential difference current conveyors (DDCCs, two grounded capacitors, and three grounded resistors is presented. The proposed oscillator provides the following advantages: the oscillation condition and oscillation frequency are orthogonally controlled; the oscillation frequency is controlled through a single grounded resistor; the use of only grounded capacitors and resistors makes the proposed circuit ideal for IC implementation; low passive and active sensitivities. Simulation results verifying the theoretical analysis are also included.

  3. Advantages of using subsurface flow constructed wetlands for wastewater treatment in space applications: Ground-based mars base prototype

    Science.gov (United States)

    Nelson, M.; Alling, A.; Dempster, W. F.; van Thillo, M.; Allen, John

    Research and design of subsurface flow wetland wastewater treatment systems for a ground-based experimental prototype Mars Base facility has been carried out, using a subsurface flow approach. These systems have distinct advantages in planetary exploration scenarios: they are odorless, relatively low-labor and low-energy, assist in purification of water and recycling of atmospheric CO2, and will support some food crops. An area of 6-8 m2 may be sufficient for integration of wetland wastewater treatment with a prototype Mars Base supporting 4-5 people. Discharge water from the wetland system will be used as irrigation water for the agricultural crop area, thus ensuring complete recycling and utilization of nutrients. Since the primary requirements for wetland treatment systems are warm temperatures and lighting, such bioregenerative systems may be integrated into early Mars base habitats, since waste heat from the lights may be used for temperature maintenance in the human living environment. "Wastewater gardens ™" can be modified for space habitats to lower space and mass requirements. Many of its construction requirements can eventually be met with use of in-situ materials, such as gravel from the Mars surface. Because the technology requires little machinery and no chemicals, and relies more on natural ecological mechanisms (microbial and plant metabolism), maintenance requirements are minimized, and systems can be expected to have long operating lifetimes. Research needs include suitability of Martian soil and gravel for wetland systems, system sealing and liner options in a Mars Base, and wetland water quality efficiency under varying temperature and light regimes.

  4. Tensile behavior of CF8-CPF8-304H and CF8M-CPF8M-316H stainless steel static and centrifugal castings

    Energy Technology Data Exchange (ETDEWEB)

    McEnerney, J.W.; Sikka, V.K.; Booker, M.K.

    1981-10-01

    We have analyzed the tensile behavior of 11 heats of grades CF8-CPF8-304H and 13 heats of grades CF8M-CPF8M-316H static and centrifugal castings from room temperature to 650/sup 0/C. Except for anomalous conditions, the centrifugal castings exhibited uniform composition. All CPF8-304H centrifugal castings contained only radial columnar grains, but some CPF8M-316H castings had columnar, banded, or equiaxed structures. Ultimate tensile strength and total elongation were the properties in which castings showed the most inferiority to wrought material. With increasing ferrite content, 0.2% yield strength and ultimate tensile strength increased while uniform elongation, total elongation, and reduction of area decreased. Although centrifugal castings did not exhibit significant end-to-end variation in tensile behavior, the 0.2% yield strength displayed anisotropy, with axial and circumferential values being greater than radial.

  5. The STACEE Ground-Based Gamma-ray Observatory

    Science.gov (United States)

    Ragan, Ken

    2002-04-01

    The Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE) is a ground-based instrument designed to study astrophysical sources of gamma rays in the energy range from 50 to 500 GeV using an array of heliostat mirrors at the National Solar Thermal Test Facility in New Mexico. The mirrors collect Cherenkov light generated by gamma-ray air showers and concentrate it onto cameras composed of photomultiplier tubes. The STACEE instrument is now complete, and uses a total of 64 heliostats. Prototype instruments, using smaller numbers of heliostats, have previously detected gamma emission from both the Crab Nebula and the Active Galactic Nucleus Mrk421. The complete instrument has a lower threshold -- approximately 50 GeV -- than those prototypes due to superior triggering and electronics, including flash ADCs for every channel.We will discuss the performance of the complete instrument in its first full season of operation, and present preliminary results of selected observations.

  6. Atmospheric contamination for CMB ground-based observations

    CERN Document Server

    Errard, J; Akiba, Y; Arnold, K; Atlas, M; Baccigalupi, C; Barron, D; Boettger, D; Borrill, J; Chapman, S; Chinone, Y; Cukierman, A; Delabrouille, J; Dobbs, M; Ducout, A; Elleflot, T; Fabbian, G; Feng, C; Feeney, S; Gilbert, A; Goeckner-Wald, N; Halverson, N W; Hasegawa, M; Hattori, K; Hazumi, M; Hill, C; Holzapfel, W L; Hori, Y; Inoue, Y; Jaehnig, G C; Jaffe, A H; Jeong, O; Katayama, N; Kaufman, J; Keating, B; Kermish, Z; Keskitalo, R; Kisner, T; Jeune, M Le; Lee, A T; Leitch, E M; Leon, D; Linder, E; Matsuda, F; Matsumura, T; Miller, N J; Myers, M J; Navaroli, M; Nishino, H; Okamura, T; Paar, H; Peloton, J; Poletti, D; Puglisi, G; Rebeiz, G; Reichardt, C L; Richards, P L; Ross, C; Rotermund, K M; Schenck, D E; Sherwin, B D; Siritanasak, P; Smecher, G; Stebor, N; Steinbach, B; Stompor, R; Suzuki, A; Tajima, O; Takakura, S; Tikhomirov, A; Tomaru, T; Whitehorn, N; Wilson, B; Yadav, A; Zahn, O

    2015-01-01

    Atmosphere is one of the most important noise sources for ground-based Cosmic Microwave Background (CMB) experiments. By increasing optical loading on the detectors, it amplifies their effective noise, while its fluctuations introduce spatial and temporal correlations between detected signals. We present a physically motivated 3d-model of the atmosphere total intensity emission in the millimeter and sub-millimeter wavelengths. We derive an analytical estimate for the correlation between detectors time-ordered data as a function of the instrument and survey design, as well as several atmospheric parameters such as wind, relative humidity, temperature and turbulence characteristics. Using numerical computation, we examine the effect of each physical parameter on the correlations in the time series of a given experiment. We then use a parametric-likelihood approach to validate the modeling and estimate atmosphere parameters from the POLARBEAR-I project first season data set. We compare our results to previous st...

  7. Observational Selection Effects with Ground-based Gravitational Wave Detectors

    CERN Document Server

    Chen, Hsin-Yu; Vitale, Salvatore; Holz, Daniel E; Katsavounidis, Erik

    2016-01-01

    Ground-based interferometers are not perfectly all-sky instruments, and it is important to account for their behavior when considering the distribution of detected events. In particular, the LIGO detectors are most sensitive to sources above North America and the Indian Ocean and, as the Earth rotates, the sensitive regions are swept across the sky. However, because the detectors do not acquire data uniformly over time, there is a net bias on detectable sources' right ascensions. Both LIGO detectors preferentially collect data during their local night; it is more than twice as likely to be local midnight than noon when both detectors are operating. We discuss these selection effects and how they impact LIGO's observations and electromagnetic follow-up. Beyond galactic foregrounds associated with seasonal variations, we find that equatorial observatories can access over $80\\%$ of the localization probability, while mid-latitudes will access closer to $70\\%$. Facilities located near the two LIGO sites can obser...

  8. Progress in the ULTRA 1-m ground-based telescope

    Science.gov (United States)

    Romeo, Robert C.; Martin, Robert N.; Twarog, Bruce; Anthony-Twarog, Barbara; Taghavi, Ray; Hale, Rick; Etzel, Paul; Fesen, Rob; Shawl, Steve

    2006-06-01

    We present the technical status of the Ultra Lightweight Telescope for Research in Astronomy (ULTRA) program. The program is a 3-year Major Research Instrumentation (MRI) program funded by NSF. The MRI is a collaborative effort involving Composite Mirror Applications, Inc. (CMA), University of Kansas, San Diego State University and Dartmouth College. Objectives are to demonstrate the feasibility of carbon fiber reinforced plastic (CFRP) composite mirror technology for ground-based optical telescopes. CMA is spearheading the development of surface replication techniques to produce the optics, fabricating the 1m glass mandrel, and constructing the optical tube assembly (OTA). Presented will be an overview and status of the 1-m mandrel fabrication, optics development, telescope design and CFRP telescope fabrication by CMA for the ULTRA Telescope.

  9. Ground-based optical observation system for LEO objects

    Science.gov (United States)

    Yanagisawa, T.; Kurosaki, H.; Oda, H.; Tagawa, M.

    2015-08-01

    We propose a ground-based optical observation system for monitoring LEO objects, which uses numerous optical sensors to cover a vast region of the sky. Its potential in terms of detection and orbital determination were examined. About 30 cm LEO objects at 1000 km altitude are detectable using an 18 cm telescope, a CCD camera and the analysis software developed. Simulations and a test observation showed that two longitudinally separate observation sites with arrays of optical sensors can identify the same objects from numerous data sets and determine their orbits precisely. The proposed system may complement or replace the current radar observation system for monitoring LEO objects, like space-situation awareness, in the near future.

  10. Optical vortex coronagraphs on ground-based telescopes

    CERN Document Server

    Jenkins, Charles

    2007-01-01

    The optical vortex coronagraph is potentially a remarkably effective device, at least for an ideal unobstructed telescope. Most ground-based telescopes however suffer from central obscuration and also have to operate through the aberrations of the turbulent atmosphere. This note analyzes the performance of the optical vortex in these circumstances and compares to some other designs, showing that it performs similarly in this situation. There is a large class of coronagraphs of this general type, and choosing between them in particular applications depends on details of performance at small off-axis distances and uniformity of response in the focal plane. Issues of manufacturability to the necessary tolerances are also likely to be important.

  11. Observational Selection Effects with Ground-based Gravitational Wave Detectors

    Science.gov (United States)

    Chen, Hsin-Yu; Essick, Reed; Vitale, Salvatore; Holz, Daniel; Katsavounidis, Erik

    2017-01-01

    Ground-based interferometers are not perfectly all-sky instruments, and it is important to account for their behavior when considering the distribution of detected events. In particular, the LIGO detectors are most sensitive to sources above North America and the Indian Ocean and, as the Earth rotates, the sensitive regions are swept across the sky. However, because the detectors do not acquire data uniformly over time, there is a net bias on detectable sources' right ascensions. Both LIGO detectors preferentially collect data during their local night; it is more than twice as likely to be local midnight than noon when both detectors are operating. We discuss these selection effects and how they impact LIGO's observations and electromagnetic follow-up. These effects can inform electromagnetic follow-up activities and optimization, including the possibility of directing observations even before gravitational-wave events occur.

  12. Ground-based Measurements of Next Generation Spectroradiometric Standard Stars

    Science.gov (United States)

    McGraw, John T.

    2013-01-01

    Accurate, radiometric standards are essential to the future of ground- and space-based astronomy and astrophysics. While astronomers tend to think of “standard stars” as available calibration sources, progress at NIST to accurately calibrate inexpensive, easy to use photodiode detectors as spectroradiometric standards from 200 nm to 1800 nm allows referencing astronomical measurements to these devices. Direction-, time-, and wavelength-dependent transmission of Earth’s atmosphere is the single largest source of error for ground-based radiometric measurement of astronomical objects. Measurements and impacts of atmospheric extinction - scattering and absorption - on imaging radiometric and spectroradiometric measurements are described. The conclusion is that accurate real-time measurement of extinction in the column of atmosphere through which standard star observations are made, over the spectral region being observed and over the field of view of the telescope are required. New techniques to directly and simultaneously measure extinction in the column of atmosphere through which observations are made are required. Our direct extinction measurement solution employs three small facility-class instruments working in parallel: a lidar to measure rapidly time variable transmission at three wavelengths with uncertainty of 0.25% per airmass, a spectrophotometer to measure rapidly wavelength variable extinction with sub-1% precision per nanometer resolution element from 350 to 1050nm, and a wide-field camera to measure angularly variable extinction over the field of view. These instruments and their operation will be described. We assert that application of atmospheric metadata provided by this instrument suite corrects for a significant fraction of systematic errors currently limiting radiometric precision, and provides a major step towards measurements that are provably dominated by random noise.

  13. Active thermal control for the 1.8-m primary mirror of the solar telescope CLST

    Science.gov (United States)

    Liu, Yangyi; Gu, Naiting; Li, Cheng; Cheng, Yuntao; Yao, Benxi; Wang, Zhiyong; Rao, Changhui

    2016-07-01

    The 1.8-m primary mirror of solar telescope is heated by the solar radiation and introduce harmful mirror seeing degrading the imaging quality. For the Chinese Large Solar Telescope (CLST), the thermal requirement based on the quantitative evaluation on mirror seeing effect shows that the temperature rise on mirror surface should be within 1 kelvin. To meet the requirement, an active thermal control system design for the CLST primary mirror is proposed, and realized on the subscale prototype of the CLST. The experimental results show that the temperature on the mirror surface is well controlled. The average and maximum thermal controlled error are less than 0.3 and 0.7 kelvins respectively, which completely meets the requirements.

  14. Hydrogeology, simulated ground-water flow, and ground-water quality, Wright-Patterson Air Force Base, Ohio

    Science.gov (United States)

    Dumouchelle, D.H.; Schalk, C.W.; Rowe, G.L.; De Roche, J.T.

    1993-01-01

    Ground water is the primary source of water in the Wright-Patterson Air Force Base area. The aquifer consists of glacial sands and gravels that fill a buried bedrock-valley system. Consolidated rocks in the area consist of poorly permeable Ordovician shale of the Richmondian stage, in the upland areas, the Brassfield Limestone of Silurian age. The valleys are filled with glacial sediments of Wisconsinan age consisting of clay-rich tills and coarse-grained outwash deposits. Estimates of hydraulic conductivity of the shales based on results of displacement/recovery tests range from 0.0016 to 12 feet per day; estimates for the glacial sediments range from less than 1 foot per day to more than 1,000 feet per day. Ground water flow from the uplands towards the valleys and the major rivers in the region, the Great Miami and the Mad Rivers. Hydraulic-head data indicate that ground water flows between the bedrock and unconsolidated deposits. Data from a gain/loss study of the Mad River System and hydrographs from nearby wells reveal that the reach of the river next to Wright-Patterson Air Force Base is a ground-water discharge area. A steady-state, three-dimensional ground-water-flow model was developed to simulate ground-water flow in the region. The model contains three layers and encompasses about 100 square miles centered on Wright-Patterson Air Force Base. Ground water enters the modeled area primarily by river leakage and underflow at the model boundary. Ground water exits the modeled area primarily by flow through the valleys at the model boundaries and through production wells. A model sensitivity analysis involving systematic changes in values of hydrologic parameters in the model indicates that the model is most sensitive to decreases in riverbed conductance and vertical conductance between the upper two layers. The analysis also indicates that the contribution of water to the buried-valley aquifer from the bedrock that forms the valley walls is about 2 to 4

  15. Aerosol optical properties over the Svalbard region of Arctic: ground-based measurements and satellite remote sensing

    Science.gov (United States)

    Gogoi, Mukunda M.; Babu, S. Suresh

    2016-05-01

    In view of the increasing anthropogenic presence and influence of aerosols in the northern polar regions, long-term continuous measurements of aerosol optical parameters have been investigated over the Svalbard region of Norwegian Arctic (Ny-Ålesund, 79°N, 12°E, 8 m ASL). This study has shown a consistent enhancement in the aerosol scattering and absorption coefficients during spring. The relative dominance of absorbing aerosols is more near the surface (lower single scattering albedo), compared to that at the higher altitude. This is indicative of the presence of local anthropogenic activities. In addition, long-range transported biomass burning aerosols (inferred from the spectral variation of absorption coefficient) also contribute significantly to the higher aerosol absorption in the Arctic spring. Aerosol optical depth (AOD) estimates from ground based Microtop sun-photometer measurements reveals that the columnar abundance of aerosols reaches the peak during spring season. Comparison of AODs between ground based and satellite remote sensing indicates that deep blue algorithm of Moderate Resolution Imaging Spectroradiometer (MODIS) retrievals over Arctic snow surfaces overestimate the columnar AOD.

  16. Independet Component Analyses of Ground-based Exoplanetary Transits

    Science.gov (United States)

    Silva Martins-Filho, Walter; Griffith, Caitlin Ann; Pearson, Kyle; Waldmann, Ingo; Biddle, Lauren; Zellem, Robert Thomas; Alvarez-Candal, Alvaro

    2016-10-01

    Most observations of exoplanetary atmospheres are conducted when a "Hot Jupiter" exoplanet transits in front of its host star. These Jovian-sized planets have small orbital periods, on the order of days, and therefore a short transit time, making them more ameanable to observations. Measurements of Hot Jupiter transits must achieve a 10-4 level of accuracy in the flux to determine the spectral modulations of the exoplanetary atmosphere. In order to accomplish this level of precision, we need to extract systematic errors, and, for ground-based measurements, the effects of Earth's atmosphere, from the signal due to the exoplanet, which is several orders of magnitudes smaller. Currently, the effects of the terrestrial atmosphere and the some of the time-dependent systematic errors are treated by dividing the host star by a reference star at each wavelength and time step of the transit. More recently, Independent Component Analyses (ICA) have been used to remove systematic effects from the raw data of space-based observations (Waldmann 2014,2012; Morello et al.,2015,2016). ICA is a statistical method born from the ideas of the blind-source separation studies, which can be used to de-trend several independent source signals of a data set (Hyvarinen and Oja, 2000). One strength of this method is that it requires no additional prior knowledge of the system. Here, we present a study of the application of ICA to ground-based transit observations of extrasolar planets, which are affected by Earth's atmosphere. We analyze photometric data of two extrasolar planets, WASP-1b and GJ3470b, recorded by the 61" Kuiper Telescope at Stewart Observatory using the Harris B and U filters. The presentation will compare the light curve depths and their dispersions as derived from the ICA analysis to those derived by analyses that ratio of the host star to nearby reference stars.References: Waldmann, I.P. 2012 ApJ, 747, 12, Waldamann, I. P. 2014 ApJ, 780, 23; Morello G. 2015 ApJ, 806

  17. Models of ionospheric VLF absorption of powerful ground based transmitters

    Science.gov (United States)

    Cohen, M. B.; Lehtinen, N. G.; Inan, U. S.

    2012-12-01

    Ground based Very Low Frequency (VLF, 3-30 kHz) radio transmitters play a role in precipitation of energetic Van Allen electrons. Initial analyses of the contribution of VLF transmitters to radiation belt losses were based on early models of trans-ionospheric propagation known as the Helliwell absorption curves, but some recent studies have found that the model overestimates (by 20-100 dB) the VLF energy reaching the magnetosphere. It was subsequently suggested that conversion of wave energy into electrostatic modes may be responsible for the error. We utilize a newly available extensive record of VLF transmitter energy reaching the magnetosphere, taken from the DEMETER satellite, and perform a direct comparison with a sophisticated full wave model of trans-ionospheric propagation. Although the model does not include the effect of ionospheric irregularities, it correctly predicts the average total power injected into the magnetosphere within several dB. The results, particularly at nighttime, appear to be robust against the variability of the ionospheric electron density. We conclude that the global effect of irregularity scattering on whistler mode conversion to quasi-electrostatic may be no larger than 6 dB.

  18. NASA's Newest Orbital Debris Ground-based Telescope Assets: MCAT and UKIRT

    Science.gov (United States)

    Lederer, S. M.; Frith, J. M.; Pace, L. F.; Cowardin, H. M.; Cowardin, H. M.; Hickson, P.; Glesne, T.; Maeda, R.; Buckalew, B.; Nishimoto, D.; hide

    2014-01-01

    NASA's Orbital Debris Program Office (ODPO) will break ground on Ascension Island in 2014 to build the newest optical (0.30 - 1.06 micrometers) ground-based telescope asset dedicated to the study of orbital debris. The Meter Class Autonomous Telescope (MCAT) is a 1.3m optical telescope designed to track objects in orbits ranging from Low Earth Orbit (LEO) to Geosynchronous Earth Orbit (GEO). Ascension Island is located in the South Atlantic Ocean, offering longitudinal sky coverage not afforded by the Ground-based Electro-Optical Deep Space Surveillance (GEODSS) network. With a fast-tracking dome, a suite of visible wide-band filters, and a time-delay integration (TDI) capable camera, MCAT is capable of multiple observing modes ranging from tracking cataloged debris targets to surveying the overall debris environment. Access to the United Kingdom Infrared Telescope (UKIRT) will extend our spectral coverage into the near- (0.8-5 micrometers) and mid- to far-infrared (8-25 micrometers) regime. UKIRT is a 3.8m telescope located on Mauna Kea on the Big Island of Hawaii. At nearly 14,000-feet and above the atmospheric inversion layer, this is one of the premier astronomical sites in the world and is an ideal setting for an infrared telescope. An unprecedented one-third of this telescope's time has been allocated to collect orbital debris data for NASA's ODPO over a 2-year period. UKIRT has several instruments available to obtain low-resolution spectroscopy in both the near-IR and the mid/far-IR. Infrared spectroscopy is ideal for constraining the material types, albedos and sizes of debris targets, and potentially gaining insight into reddening effects caused by space weathering. In addition, UKIRT will be used to acquire broadband photometric imaging at GEO with the Wide Field Camera (WFCAM) for studying known objects of interest as well as collecting data in survey-mode to discover new targets. Results from the first stage of the debris campaign will be presented. The

  19. Probing Pluto's Atmosphere Using Ground-Based Stellar Occultations

    Science.gov (United States)

    Sicardy, Bruno; Rio de Janeiro Occultation Team, Granada Team, International Occultation and Timing Association, Royal Astronomical Society New Zealand Occultation Section, Lucky Star associated Teams

    2016-10-01

    Over the last three decades, some twenty stellar occultations by Pluto have been monitored from Earth. They occur when the dwarf planet blocks the light from a star for a few minutes as it moves on the sky. Such events led to the hint of a Pluto's atmosphere in 1985, that was fully confirmed during another occultation in 1988, but it was only in 2002 that a new occultation could be recorded. From then on, the dwarf planet started to move in front of the galactic center, which amplified by a large factor the number of events observable per year.Pluto occultations are essentially refractive events during which the stellar rays are bent by the tenuous atmosphere, causing a gradual dimming of the star. This provides the density, pressure and temperature profiles of the atmosphere from a few kilometers above the surface up to about 250 km altitude, corresponding respectively to pressure levels of about 10 and 0.1 μbar. Moreover, the extremely fine spatial resolution (a few km) obtained through this technique allows the detection of atmospheric gravity waves, and permits in principle the detection of hazes, if present.Several aspects make Pluto stellar occultations quite special: first, they are the only way to probe Pluto's atmosphere in detail, as the dwarf planet is far too small on the sky and the atmosphere is far too tenuous to be directly imaged from Earth. Second, they are an excellent example of participative science, as many amateurs have been able to record those events worldwide with valuable scientific returns, in collaboration with professional astronomers. Third, they reveal Pluto's climatic changes on decade-scales and constrain the various seasonal models currently explored.Finally, those observations are fully complementary to space exploration, in particular with the New Horizons (NH) mission. I will show how ground-based occultations helped to better calibrate some NH profiles, and conversely, how NH results provide some key boundary conditions

  20. Observing Tsunamis in the Ionosphere Using Ground Based GPS Measurements

    Science.gov (United States)

    Galvan, D. A.; Komjathy, A.; Song, Y. Tony; Stephens, P.; Hickey, M. P.; Foster, J.

    2011-01-01

    Ground-based Global Positioning System (GPS) measurements of ionospheric Total Electron Content (TEC) show variations consistent with atmospheric internal gravity waves caused by ocean tsunamis following recent seismic events, including the Tohoku tsunami of March 11, 2011. We observe fluctuations correlated in time, space, and wave properties with this tsunami in TEC estimates processed using JPL's Global Ionospheric Mapping Software. These TEC estimates were band-pass filtered to remove ionospheric TEC variations with periods outside the typical range of internal gravity waves caused by tsunamis. Observable variations in TEC appear correlated with the Tohoku tsunami near the epicenter, at Hawaii, and near the west coast of North America. Disturbance magnitudes are 1-10% of the background TEC value. Observations near the epicenter are compared to estimates of expected tsunami-driven TEC variations produced by Embry Riddle Aeronautical University's Spectral Full Wave Model, an atmosphere-ionosphere coupling model, and found to be in good agreement. The potential exists to apply these detection techniques to real-time GPS TEC data, providing estimates of tsunami speed and amplitude that may be useful for future early warning systems.

  1. Tissue Engineering of Cartilage on Ground-Based Facilities

    Science.gov (United States)

    Aleshcheva, Ganna; Bauer, Johann; Hemmersbach, Ruth; Egli, Marcel; Wehland, Markus; Grimm, Daniela

    2016-06-01

    Investigations under simulated microgravity offer the opportunity for a better understanding of the influence of altered gravity on cells and the scaffold-free three-dimensional (3D) tissue formation. To investigate the short-term influence, human chondrocytes were cultivated for 2 h, 4 h, 16 h, and 24 h on a 2D Fast-Rotating Clinostat (FRC) in DMEM/F-12 medium supplemented with 10 % FCS. We detected holes in the vimentin network, perinuclear accumulations of vimentin after 2 h, and changes in the chondrocytes shape visualised by F-actin staining after 4 h of FRC-exposure. Scaffold-free cultivation of chondrocytes for 7 d on the Random Positioning Machine (RPM), the FRC and the Rotating Wall Vessel (RWV) resulted in spheroid formation, a phenomenon already known from spaceflight experiments with chondrocytes (MIR Space Station) and thyroid cancer cells (SimBox/Shenzhou-8 space mission). The experiments enabled by the ESA-CORA-GBF programme gave us an optimal opportunity to study gravity-related cellular processes, validate ground-based facilities for our chosen cell system, and prepare long-term experiments under real microgravity conditions in space

  2. Theoretical validation of ground-based microwave ozone observations

    Directory of Open Access Journals (Sweden)

    P. Ricaud

    Full Text Available Ground-based microwave measurements of the diurnal and seasonal variations of ozoneat 42±4.5 and 55±8 km are validated by comparing with results from a zero-dimensional photochemical model and a two-dimensional (2D chemical/radiative/dynamical model, respectively. O3 diurnal amplitudes measured in Bordeaux are shown to be in agreement with theory to within 5%. For the seasonal analysis of O3 variation, at 42±4.5 km, the 2D model underestimates the yearly averaged ozone concentration compared with the measurements. A double maximum oscillation (~3.5% is measured in Bordeaux with an extended maximum in September and a maximum in February, whilst the 2D model predicts only a single large maximum (17% in August and a pronounced minimum in January. Evidence suggests that dynamical transport causes the winter O3 maximum by propagation of planetary waves, phenomena which are not explicitly reproduced by the 2D model. At 55±8 km, the modeled yearly averaged O3 concentration is in very good agreement with the measured yearly average. A strong annual oscillation is both measured and modeled with differences in the amplitude shown to be exclusively linked to temperature fields.

  3. Atmospheric Refraction Path Integrals in Ground-Based Interferometry

    CERN Document Server

    Mathar, R J

    2004-01-01

    The basic effect of the earth's atmospheric refraction on telescope operation is the reduction of the true zenith angle to the apparent zenith angle, associated with prismatic aberrations due to the dispersion in air. If one attempts coherent superposition of star images in ground-based interferometry, one is in addition interested in the optical path length associated with the refracted rays. In a model of a flat earth, the optical path difference between these is not concerned as the translational symmetry of the setup means no net effect remains. Here, I evaluate these interferometric integrals in the more realistic arrangement of two telescopes located on the surface of a common earth sphere and point to a star through an atmosphere which also possesses spherical symmetry. Some focus is put on working out series expansions in terms of the small ratio of the baseline over the earth radius, which allows to bypass some numerics which otherwise is challenged by strong cancellation effects in building the opti...

  4. Experiments on a Ground-Based Tomographic Synthetic Aperture Radar

    Directory of Open Access Journals (Sweden)

    Hoonyol Lee

    2016-08-01

    Full Text Available This paper presents the development and experiment of three-dimensional image formation by using a ground-based tomographic synthetic aperture radar (GB-TomoSAR system. GB-TomoSAR formulates two-dimensional synthetic aperture by the motion of antennae, both in azimuth and vertical directions. After range compression, three-dimensional image focusing is performed by applying Deramp-FFT (Fast Fourier Transform algorithms, both in azimuth and vertical directions. Geometric and radiometric calibrations were applied to make an image cube, which is then projected into range-azimuth and range-vertical cross-sections for visualization. An experiment with a C-band GB-TomoSAR system with a scan length of 2.49 m and 1.86 m in azimuth and vertical-direction, respectively, shows distinctive three-dimensional radar backscattering of stable buildings and roads with resolutions similar to the theoretical values. Unstable objects such as trees and moving cars generate severe noise due to decorrelation during the eight-hour image-acquisition time.

  5. Satellite Type Estination from Ground-based Photometric Observation

    Science.gov (United States)

    Endo, T.; Ono, H.; Suzuki, J.; Ando, T.; Takanezawa, T.

    2016-09-01

    The optical photometric observation is potentially a powerful tool for understanding of the Geostationary Earth Orbit (GEO) objects. At first, we measured in laboratory the surface reflectance of common satellite materials, for example, Multi-layer Insulation (MLI), mono-crystalline silicon cells, and Carbon Fiber Reinforced Plastic (CFRP). Next, we calculated visual magnitude of a satellite by simplified shape and albedo. In this calculation model, solar panels have dimensions of 2 by 8 meters, and the bus area is 2 meters squared with measured optical properties described above. Under these conditions, it clarified the brightness can change the range between 3 and 4 magnitudes in one night, but color index changes only from 1 to 2 magnitudes. Finally, we observed the color photometric data of several GEO satellites visible from Japan multiple times in August and September 2014. We obtained that light curves of GEO satellites recorded in the B and V bands (using Johnson filters) by a ground-base optical telescope. As a result, color index changed approximately from 0.5 to 1 magnitude in one night, and the order of magnitude was not changed in all cases. In this paper, we briefly discuss about satellite type estimation using the relation between brightness and color index obtained from the photometric observation.

  6. VME-based remote instrument control without ground loops

    CERN Document Server

    Belleman, J; González, J L

    1997-01-01

    New electronics has been developed for the remote control of the pick-up electrodes at the CERN Proton Synchrotron (PS). Communication between VME-based control computers and remote equipment is via full duplex point-to-point digital data links. Data are sent and received in serial format over simple twisted pairs at a rate of 1 Mbit/s, for distances of up to 300 m. Coupling transformers are used to avoid ground loops. The link hardware consists of a general-purpose VME-module, the 'TRX' (transceiver), containing four FIFO-buffered communication channels, and a dedicated control card for each remote station. Remote transceiver electronics is simple enough not to require micro-controllers or processors. Currently, some sixty pick-up stations of various types, all over the PS Complex (accelerators and associated beam transfer lines) are equipped with the new system. Even though the TRX was designed primarily for communication with pick-up electronics, it could also be used for other purposes, for example to for...

  7. Ground-based measurements of UV Index (UVI at Helwan

    Directory of Open Access Journals (Sweden)

    H. Farouk

    2012-12-01

    Full Text Available On October 2010 UV Index (UVI ground-based measurements were carried out by weather station at solar laboratory in NRIAG. The daily variation has maximum values in spring and summer days, while minimum values in autumn and winter days. The low level of UVI between 2.55 and 2.825 was found in December, January and February. The moderate level of UVI between 3.075 and 5.6 was found in March, October and November. The high level of UVI between 6.7 and 7.65 was found in April, May and September. The very high level of UVI between 8 and 8.6 was found in June, July and August. High level of radiation over 6 months per year including 3 months with a very high level UVI. According to the equation {UVI=a[SZA]b} the UVI increases with decreasing SZA by 82% on a daily scale and 88% on a monthly scale. Helwan exposure to a high level of radiation over 6 months per year including 3 months with a very high level UVI, so it is advisable not to direct exposure to the sun from 11 am to 2:00 pm.

  8. Ground-based monitoring of solar radiation in Moldova

    Science.gov (United States)

    Aculinin, Alexandr; Smicov, Vladimir

    2010-05-01

    Integrated measurements of solar radiation in Kishinev, Moldova have been started by Atmospheric Research Group (ARG) at the Institute of Applied Physics from 2003. Direct, diffuse and total components of solar and atmospheric long-wave radiation are measured by using of the radiometric complex at the ground-based solar radiation monitoring station. Measurements are fulfilled at the stationary and moving platforms equipped with the set of 9 broadband solar radiation sensors overlapping wavelength range from UV-B to IR. Detailed description of the station can be found at the site http://arg.phys.asm.md. Ground station is placed in an urban environment of Kishinev city (47.00N; 28.56E). Summary of observation data acquired at the station in the course of short-term period from 2004 to 2009 are presented below. Solar radiation measurements were fulfilled by using CM11(280-3000 nm) and CH1 sensors (Kipp&Zonen). In the course of a year maximum and minimum of monthly sums of total radiation was ~706.4 MJm-2 in June and ~82.1MJm-2 in December, respectively. Monthly sums of direct solar radiation (on horizontal plane) show the maximum and minimum values of the order ~456.9 MJm-2 in July and ~25.5MJm-2 in December, respectively. In an average, within a year should be marked the predominance of direct radiation over the scattered radiation, 51% and 49%, respectively. In the course of a year, the percentage contribution of the direct radiation into the total radiation is ~55-65% from May to September. In the remaining months, the percentage contribution decreases and takes the minimum value of ~ 28% in December. In an average, annual sum of total solar radiation is ~4679.9 MJm-2. For the period from April to September accounts for ~76% of the annual amount of total radiation. Annual sum of sunshine duration accounts for ~2149 hours, which is of ~ 48% from the possible sunshine duration. In an average, within a year maximum and minimum of sunshine duration is ~ 304 hours in

  9. GVT-Based Ground Flutter Test without Wind Tunnel Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ZONA Technology, Inc (ZONA) and Arizona State University (ASU) propose a R&D effort to develop a ground flutter testing system without wind tunnel, called the...

  10. GVT-Based Ground Flutter Test without Wind Tunnel Project

    Data.gov (United States)

    National Aeronautics and Space Administration — ZONA Technology, Inc (ZONA) and Arizona State University (ASU) propose a R&D effort to further develop the ground flutter testing system in place of a wind...

  11. System of gait analysis based on ground reaction force assessment

    Directory of Open Access Journals (Sweden)

    František Vaverka

    2015-12-01

    Full Text Available Background: Biomechanical analysis of gait employs various methods used in kinematic and kinetic analysis, EMG, and others. One of the most frequently used methods is kinetic analysis based on the assessment of the ground reaction forces (GRF recorded on two force plates. Objective: The aim of the study was to present a method of gait analysis based on the assessment of the GRF recorded during the stance phase of two steps. Methods: The GRF recorded with a force plate on one leg during stance phase has three components acting in directions: Fx - mediolateral, Fy - anteroposterior, and Fz - vertical. A custom-written MATLAB script was used for gait analysis in this study. This software displays instantaneous force data for both legs as Fx(t, Fy(t and Fz(t curves, automatically determines the extremes of functions and sets the visual markers defining the individual points of interest. Positions of these markers can be easily adjusted by the rater, which may be necessary if the GRF has an atypical pattern. The analysis is fully automated and analyzing one trial takes only 1-2 minutes. Results: The method allows quantification of temporal variables of the extremes of the Fx(t, Fy(t, Fz(t functions, durations of the braking and propulsive phase, duration of the double support phase, the magnitudes of reaction forces in extremes of measured functions, impulses of force, and indices of symmetry. The analysis results in a standardized set of 78 variables (temporal, force, indices of symmetry which can serve as a basis for further research and diagnostics. Conclusions: The resulting set of variable offers a wide choice for selecting a specific group of variables with consideration to a particular research topic. The advantage of this method is the standardization of the GRF analysis, low time requirements allowing rapid analysis of a large number of trials in a short time, and comparability of the variables obtained during different research measurements.

  12. Lightweight off-axis 8-m class telescope: a case study to ELT approximation

    Science.gov (United States)

    Ruiz, Elfego; Sohn, Erika; Luna, Esteban; Salas, Luis; Cruz-Gonzalez, Irene

    2004-07-01

    Two main trends presently prevail in ELT design: arrays of hundreds of small (1 - 2 m) hexagonal mirrors and the use of several large (~8m) monolithic mirrors. We present a conceptual study of an off axis 8 m telescope with different mirror options, which can be useful as an experiment towards the design of large multi-mirror telescopes, in terms of different mirror materials, ideas for the optics and new solutions for the telescope mechanical assembly.

  13. Characterization of subarctic vegetation using ground based remote sensing methods

    Science.gov (United States)

    Finnell, D.; Garnello, A.; Palace, M. W.; Sullivan, F.; Herrick, C.; Anderson, S. M.; Crill, P. M.; Varner, R. K.

    2014-12-01

    Stordalen mire is located at 68°21'N and 19°02'E in the Swedish subarctic. Climate monitoring has revealed a warming trend spanning the past 150 years affecting the mires ability to hold stable palsa/hummock mounds. The micro-topography of the landscape has begun to degrade into thaw ponds changing the vegetation cover from ombrothrophic to minerotrophic. Hummocks are ecologically important due to their ability to act as a carbon sinks. Thaw ponds and sphagnum rich transitional zones have been documented as sources of atmospheric CH4. An objective of this project is to determine if a high resolution three band camera (RGB) and a RGNIR camera could detect differences in vegetation over five different site types. Species composition was collected for 50 plots with ten repetitions for each site type: palsa/hummock, tall shrub, semi-wet, tall graminoid, and wet. Sites were differentiated based on dominating species and features consisting of open water presence, sphagnum spp. cover, graminoid spp. cover, or the presence of dry raised plateaus/mounds. A pole based camera mount was used to collect images at a height of ~2.44m from the ground. The images were cropped in post-processing to fit a one-square meter quadrat. Texture analysis was performed on all images, including entropy, lacunarity, and angular second momentum. Preliminary results suggested that site type influences the number of species present. The p-values for the ability to predict site type using a t-test range from <0.0001 to 0.0461. A stepwise discriminant analysis on site type vs. texture yielded a 10% misclassification rate. Through the use of a stepwise regression of texture variables, actual vs. predicted percent of vegetation coverage provided R squared values of 0.73, 0.71, 0.67, and 0.89 for C. bigelowii, R. chamaemorus, Sphagnum spp., and open water respectively. These data have provided some support to the notion that texture analyses can be used for classification of mire site types. Future

  14. Observational Selection Effects with Ground-based Gravitational Wave Detectors

    Science.gov (United States)

    Chen, Hsin-Yu; Essick, Reed; Vitale, Salvatore; Holz, Daniel E.; Katsavounidis, Erik

    2017-01-01

    Ground-based interferometers are not perfect all-sky instruments, and it is important to account for their behavior when considering the distribution of detected events. In particular, the LIGO detectors are most sensitive to sources above North America and the Indian Ocean, and as the Earth rotates, the sensitive regions are swept across the sky. However, because the detectors do not acquire data uniformly over time, there is a net bias on detectable sources’ right ascensions. Both LIGO detectors preferentially collect data during their local night; it is more than twice as likely to be local midnight than noon when both detectors are operating. We discuss these selection effects and how they impact LIGO’s observations and electromagnetic (EM) follow-up. Beyond galactic foregrounds associated with seasonal variations, we find that equatorial observatories can access over 80% of the localization probability, while mid-latitudes will access closer to 70%. Facilities located near the two LIGO sites can observe sources closer to their zenith than their analogs in the south, but the average observation will still be no closer than 44° from zenith. We also find that observatories in Africa or the South Atlantic will wait systematically longer before they can begin observing compared to the rest of the world though, there is a preference for longitudes near the LIGOs. These effects, along with knowledge of the LIGO antenna pattern, can inform EM follow-up activities and optimization, including the possibility of directing observations even before gravitational-wave events occur.

  15. Ozone profiles above Kiruna from two ground-based radiometers

    Science.gov (United States)

    Ryan, Niall J.; Walker, Kaley A.; Raffalski, Uwe; Kivi, Rigel; Gross, Jochen; Manney, Gloria L.

    2016-09-01

    This paper presents new atmospheric ozone concentration profiles retrieved from measurements made with two ground-based millimetre-wave radiometers in Kiruna, Sweden. The instruments are the Kiruna Microwave Radiometer (KIMRA) and the Millimeter wave Radiometer 2 (MIRA 2). The ozone concentration profiles are retrieved using an optimal estimation inversion technique, and they cover an altitude range of ˜ 16-54 km, with an altitude resolution of, at best, 8 km. The KIMRA and MIRA 2 measurements are compared to each other, to measurements from balloon-borne ozonesonde measurements at Sodankylä, Finland, and to measurements made by the Microwave Limb Sounder (MLS) aboard the Aura satellite. KIMRA has a correlation of 0.82, but shows a low bias, with respect to the ozonesonde data, and MIRA 2 shows a smaller magnitude low bias and a 0.98 correlation coefficient. Both radiometers are in general agreement with each other and with MLS data, showing high correlation coefficients, but there are differences between measurements that are not explained by random errors. An oscillatory bias with a peak of approximately ±1 ppmv is identified in the KIMRA ozone profiles over an altitude range of ˜ 18-35 km, and is believed to be due to baseline wave features that are present in the spectra. A time series analysis of KIMRA ozone for winters 2008-2013 shows the existence of a local wintertime minimum in the ozone profile above Kiruna. The measurements have been ongoing at Kiruna since 2002 and late 2012 for KIMRA and MIRA 2, respectively.

  16. Project management for complex ground-based instruments: MEGARA plan

    Science.gov (United States)

    García-Vargas, María. Luisa; Pérez-Calpena, Ana; Gil de Paz, Armando; Gallego, Jesús; Carrasco, Esperanza; Cedazo, Raquel; Iglesias, Jorge

    2014-08-01

    The project management of complex instruments for ground-based large telescopes is a challenge itself. A good management is a clue for project success in terms of performance, schedule and budget. Being on time has become a strict requirement for two reasons: to assure the arrival at the telescope due to the pressure on demanding new instrumentation for this first world-class telescopes and to not fall in over-costs. The budget and cash-flow is not always the expected one and has to be properly handled from different administrative departments at the funding centers worldwide distributed. The complexity of the organizations, the technological and scientific return to the Consortium partners and the participation in the project of all kind of professional centers working in astronomical instrumentation: universities, research centers, small and large private companies, workshops and providers, etc. make the project management strategy, and the tools and procedures tuned to the project needs, crucial for success. MEGARA (Multi-Espectrógrafo en GTC de Alta Resolución para Astronomía) is a facility instrument of the 10.4m GTC (La Palma, Spain) working at optical wavelengths that provides both Integral-Field Unit (IFU) and Multi-Object Spectrograph (MOS) capabilities at resolutions in the range R=6,000-20,000. The project is an initiative led by Universidad Complutense de Madrid (Spain) in collaboration with INAOE (Mexico), IAA-CSIC (Spain) and Universidad Politécnica de Madrid (Spain). MEGARA is being developed under contract with GRANTECAN.

  17. A coherency function model of ground motion at base rock corresponding to strike-slip fault

    Institute of Scientific and Technical Information of China (English)

    丁海平; 刘启方; 金星; 袁一凡

    2004-01-01

    At present, the method to study spatial variation of ground motions is statistic analysis based on dense array records such as SMART-1 array, etc. For lacking of information of ground motions, there is no coherency function model of base rock and different style site. Spatial variation of ground motions in elastic media is analyzed by deterministic method in this paper. Taking elastic half-space model with dislocation source of fault, near-field ground motions are simulated. This model takes strike-slip fault and earth media into account. A coherency function is proposed for base rock site.

  18. KASINICS: Near Infrared Camera System for the BOAO 1.8m Telescope

    Science.gov (United States)

    Moon, Bongkon; Jin, Ho; Yuk, In-Soo; Lee, Sungho; Nam, Uk-Won; Cha, Sang-Mok; Cho, Seoung-Hyun; Kyeong, Jae-Mann; Park, Youngsik; Mock, Seungwon; Han, Jeong-Yeol; Lee, Dea-Hee; Park, Jang-Hyun; Han, Wonyong; Pak, Soojong; Kim, Geon-Hee; Kim, Yong Ha

    2008-08-01

    We developed Korea Astronomy and Space science Institute (KASI) Near Infrared Camera System (KASINICS) to be installed on the 1.8m telescope of Bohyunsan Optical Astronomy Observatory (BOAO) in Korea. We use a 512×512 InSb array (Aladdin III Quadrant, Raytheon Co.) to enable L band observations as well as J, H, and KS bands. The field-of-view of the array is 3.3'× 3.3' with a resolution of 0.39''/ pixel. We adopt an Offner relay optical system, which provides a cold stop to eliminate thermal background emission from the telescope structures. Most parts of the camera, including the mirrors, were manufactured from the same ingot of aluminum alloy to ensure a homologous contraction from room temperature to 80K. We also developed a readout electronics system for the array detector. Based on preliminary results from test observations, the limiting magnitudes are J = 17.6, H = 17.5, KS = 16.1, and L(narrow) = 10.0mag at a signal-to-noise ratio of 10 for an integration time of 100s.

  19. Scaling earthquake ground motions for performance-based assessment of buildings

    Science.gov (United States)

    Huang, Y.-N.; Whittaker, A.S.; Luco, N.; Hamburger, R.O.

    2011-01-01

    The impact of alternate ground-motion scaling procedures on the distribution of displacement responses in simplified structural systems is investigated. Recommendations are provided for selecting and scaling ground motions for performance-based assessment of buildings. Four scaling methods are studied, namely, (1)geometric-mean scaling of pairs of ground motions, (2)spectrum matching of ground motions, (3)first-mode-period scaling to a target spectral acceleration, and (4)scaling of ground motions per the distribution of spectral demands. Data were developed by nonlinear response-history analysis of a large family of nonlinear single degree-of-freedom (SDOF) oscillators that could represent fixed-base and base-isolated structures. The advantages and disadvantages of each scaling method are discussed. The relationship between spectral shape and a ground-motion randomness parameter, is presented. A scaling procedure that explicitly considers spectral shape is proposed. ?? 2011 American Society of Civil Engineers.

  20. Ground-based gamma-ray telescopes as ground stations in deep-space lasercom

    CERN Document Server

    Carrasco-Casado, Alberto; Vergaz, Ricardo

    2016-01-01

    As the amount of information to be transmitted from deep-space rapidly increases, the radiofrequency technology has become a bottleneck in space communications. RF is already limiting the scientific outcome of deep-space missions and could be a significant obstacle in the developing of manned missions. Lasercom holds the promise to solve this problem, as it will considerably increase the data rate while decreasing the energy, mass and volume of onboard communication systems. In RF deep-space communications, where the received power is the main limitation, the traditional approach to boost the data throughput has been increasing the receiver's aperture, e.g. the 70-m antennas in the NASA's Deep Space Network. Optical communications also can benefit from this strategy, thus 10-m class telescopes have typically been suggested to support future deep-space links. However, the cost of big telescopes increase exponentially with their aperture, and new ideas are needed to optimize this ratio. Here, the use of ground-...

  1. Biosensors for EVA: Improved Instrumentation for Ground-based Studies

    Science.gov (United States)

    Soller, B.; Ellerby, G.; Zou, F.; Scott, P.; Jin, C.; Lee, S. M. C.; Coates, J.

    2010-01-01

    During lunar excursions in the EVA suit, real-time measurement of metabolic rate is required to manage consumables and guide activities to ensure safe return to the base. Metabolic rate, or oxygen consumption (VO2), is normally measured from pulmonary parameters but cannot be determined with standard techniques in the oxygen-rich environment of a spacesuit. Our group has developed novel near infrared spectroscopic (NIRS) methods to calculate muscle oxygen saturation (SmO 2), hematocrit, and pH, and we recently demonstrated that we can use our NIRS sensor to measure VO 2 on the leg during cycling. Our NSBRI project has 4 objectives: (1) increase the accuracy of the metabolic rate calculation through improved prediction of stroke volume; (2) investigate the relative contributions of calf and thigh oxygen consumption to metabolic rate calculation for walking and running; (3) demonstrate that the NIRS-based noninvasive metabolic rate methodology is sensitive enough to detect decrement in VO 2 in a space analog; and (4) improve instrumentation to allow testing within a spacesuit. Over the past year we have made progress on all four objectives, but the most significant progress was made in improving the instrumentation. The NIRS system currently in use at JSC is based on fiber optics technology. Optical fiber bundles are used to deliver light from a light source in the monitor to the patient, and light reflected back from the patient s muscle to the monitor for spectroscopic analysis. The fiber optic cables are large and fragile, and there is no way to get them in and out of the test spacesuit used for ground-based studies. With complimentary funding from the US Army, we undertook a complete redesign of the sensor and control electronics to build a novel system small enough to be used within the spacesuit and portable enough to be used by a combat medic. In the new system the filament lamp used in the fiber optic system was replaced with a novel broadband near infrared

  2. Biosensors for EVA: Improved Instrumentation for Ground-based Studies

    Science.gov (United States)

    Soller, B.; Ellerby, G.; Zou, F.; Scott, P.; Jin, C.; Lee, S. M. C.; Coates, J.

    2010-01-01

    During lunar excursions in the EVA suit, real-time measurement of metabolic rate is required to manage consumables and guide activities to ensure safe return to the base. Metabolic rate, or oxygen consumption (VO2), is normally measured from pulmonary parameters but cannot be determined with standard techniques in the oxygen-rich environment of a spacesuit. Our group has developed novel near infrared spectroscopic (NIRS) methods to calculate muscle oxygen saturation (SmO 2), hematocrit, and pH, and we recently demonstrated that we can use our NIRS sensor to measure VO 2 on the leg during cycling. Our NSBRI project has 4 objectives: (1) increase the accuracy of the metabolic rate calculation through improved prediction of stroke volume; (2) investigate the relative contributions of calf and thigh oxygen consumption to metabolic rate calculation for walking and running; (3) demonstrate that the NIRS-based noninvasive metabolic rate methodology is sensitive enough to detect decrement in VO 2 in a space analog; and (4) improve instrumentation to allow testing within a spacesuit. Over the past year we have made progress on all four objectives, but the most significant progress was made in improving the instrumentation. The NIRS system currently in use at JSC is based on fiber optics technology. Optical fiber bundles are used to deliver light from a light source in the monitor to the patient, and light reflected back from the patient s muscle to the monitor for spectroscopic analysis. The fiber optic cables are large and fragile, and there is no way to get them in and out of the test spacesuit used for ground-based studies. With complimentary funding from the US Army, we undertook a complete redesign of the sensor and control electronics to build a novel system small enough to be used within the spacesuit and portable enough to be used by a combat medic. In the new system the filament lamp used in the fiber optic system was replaced with a novel broadband near infrared

  3. Seismic Responses of Asymmetric Base-Isolated Structures under Near-Fault Ground Motion

    Institute of Scientific and Technical Information of China (English)

    YE Kun; LI Li; FANG Qin-han

    2008-01-01

    An inter-story shear model of asymmetric base-isolated structures incorporating deformation of each isolation bearing was built, and a method to simultaneously simulate bi-directional near-fault and far-field ground motions was proposed. A comparative study on the dynamic responses of asymmetric base-isolated structures under near-fault and far-field ground motions were conducted to investigate the effects of eccentricity in the isolation system and in the superstructures, the ratio of the uncoupled torsional to lateral frequency of the superstructure and the pulse period of near-fault ground motions on the nonlinear seismic response of asymmetric base-isolated structures. Numerical results show that eccentricity in the isolation system makes asymmetric base-isolated structure more sensitive to near-fault ground motions, and the pulse period of near-fault ground motions plays an import role in governing the seismic responses of asymmetric base-isolated structures.

  4. NO2 DOAS measurements from ground and space: comparison of ground based measurements and OMI data in Mexico City

    Science.gov (United States)

    Rivera, C.; Stremme, W.; Grutter, M.

    2012-04-01

    The combination of satellite data and ground based measurements can provide valuable information about atmospheric chemistry and air quality. In this work we present a comparison between measured ground based NO2 differential columns at the Universidad Nacional Autónoma de México (UNAM) in Mexico City, using the Differential Optical Absorption Spectroscopy (DOAS) technique and NO2 total columns measured by the Ozone Monitoring Instrument (OMI) onboard the Aura satellite using the same measurement technique. From these data, distribution maps of average NO2 above the Mexico basin were constructed and hot spots inside the city could be identified. In addition, a clear footprint was detected from the Tula industrial area, ~50 km northwest of Mexico City, where a refinery, a power plant and other industries are located. A less defined footprint was identified in the Cuernavaca basin, South of Mexico City, and the nearby cities of Toluca and Puebla do not present strong enhancements in the NO2 total columns. With this study we expect to cross-validate space and ground measurements and provide useful information for future studies.

  5. ASTRO-1: a 1.8m unobscured space observatory for next generation UV/visible astrophysics and exoplanet exploration

    Science.gov (United States)

    Matthews, Gary W.; Egerman, Robert; Morse, Jon A.; Wilkes, Belinda

    2016-07-01

    The Hubble Space Telescope has been a scientific marvel that has provided unimaginable imagery and scientific discovery. Its exquisite UV/Visible imaging performance is unmatched from the ground. In NASA's future planning, the earliest possible successor mission would be in the 3030s, well beyond the expected lifetime of Hubble. The ASTRO-1 space telescope is a 1.8m off-axis (unobscured) observatory that looks to fill this critical void with Hubble-like performance to continue the scientific quest while also providing the possibility for exoplanet research with a coronagraphic instrument and/or a free flying starshade. BoldlyGo Institute seeks to reach beyond NASA funding to leverage the high public interest in space research and exploration, and the search for life beyond Earth.

  6. Ground-based Space Weather Monitoring with LOFAR

    Science.gov (United States)

    Wise, Michael; van Haarlem, Michiel; Lawrence, Gareth; Reid, Simon; Bos, Andre; Rawlings, Steve; Salvini, Stef; Mitchell, Cathryn; Soleimani, Manuch; Amado, Sergio; Teresa, Vital

    As one of the first of a new generation of radio instruments, the International LOFAR Telescope (ILT) will provide a number of unique and novel capabilities for the astronomical community. These include remote configuration and operation, dynamic real-time processing and system response, and the ability to provide multiple simultaneous streams of data to a community whose scientific interests run the gamut from lighting in the atmospheres of distant planets to the origins of the universe itself. The LOFAR (LOw Frequency ARray) system is optimized for a frequency range from 30-240 MHz and consists of multiple antenna fields spread across Europe. In the Netherlands, a total 36 LOFAR stations are nearing completion with an initial 8 international stations currently being deployed in Germany, France, Sweden, and the UK. Digital beam-forming techniques make the LOFAR system agile and allow for rapid repointing of the telescope as well as the potential for multiple simultaneous observations. With its dense core array and long interferometric baselines, LOFAR has the potential to achieve unparalleled sensitivity and spatial resolution in the low frequency radio regime. LOFAR will also be one of the first radio observatories to feature automated processing pipelines to deliver fully calibrated science products to its user community. As we discuss in this presentation, the same capabilities that make LOFAR a powerful tool for radio astronomy also provide an excellent platform upon which to build a ground-based monitoring system for space weather events. For example, the ability to monitor Solar activity in near real-time is one of the key scientific capabilities being developed for LOFAR. With only a fraction of its total observing capacity, LOFAR will be able to provide continuous monitoring of the Solar spectrum over the entire 10-240 MHz band down to microsecond timescales. Autonomous routines will scan these incoming spectral data for evidence of Solar flares and be

  7. Analyses of Cryogenic Propellant Tank Pressurization based upon Ground Experiments

    OpenAIRE

    Ludwig, Carina; Dreyer, Michael

    2012-01-01

    The pressurization system of cryogenic propellant rockets requires on-board pressurant gas. The objective of this study was to analyze the influence of the pressurant gas temperature on the required pressurant gas mass in terms of lowering the launcher mass. First, ground experiments were performed in order to investigate the pressurization process with regard to the influence of the pressurant gas inlet temperature. Second, a system study for the cryogenic upper stage of a sma...

  8. Ground-based Remote Sensing of Cloud Liquid Water Path

    Science.gov (United States)

    Crewell, S.; Loehnert, U.

    Within the BALTEX Cloud LIquid WAter NETwork (CLIWA-NET) measurements of cloud parameters were performed to improve/evaluate cloud parameterizations in numerical weather prediction and climate models. The key variable is the cloud liq- uid water path (LWP) which is measured by passive microwave radiometry from the ground during three two-month CLIWA-NET observational periods. Additionally to the high temporal resolution time series from the ground, LWP fields are derived from satellite measurements. During the first two campaigns a continental scale network consisting of 12 stations was established. Most stations included further cloud sen- sitive instruments like infrared radiometer and lidar ceilometer. The third campaign started with a two-week long microwave intercomparison campaign (MICAM) in Cabauw, The Netherlands, and proceeded with a regional network within a 100 by 100 km area. The presentation will focus on the accuracy of LWP derived from the ground by in- vestigating the accuracy of the microwave brightness temperature measurement and examining the LWP retrieval uncertainty. Up to now microwave radiometer are no standard instruments and the seven radiometer involved in MICAM differ in frequen- cies, bandwidths, angular resolution, integration time etc. The influence of this instru- ment specifications on the LWP retrieval will be discussed.

  9. Forsøg med 4,8 m langt lydvaffelelement

    DEFF Research Database (Denmark)

    Hansen, Lars Pilegaard

    Denne rapport omhandler den statiske eftervisning af Betonelements A/S's 4,8 m lange lydregulerende vaffelplade, i det følgende benævnt vaflen. Vaflen påtænkes anvendt i tagkonstruktioner til udfyldning mellem ribbeetagplader (RTP), hvor også den skivevirkning udnyttes. Vaflen har gode akutstikre......Denne rapport omhandler den statiske eftervisning af Betonelements A/S's 4,8 m lange lydregulerende vaffelplade, i det følgende benævnt vaflen. Vaflen påtænkes anvendt i tagkonstruktioner til udfyldning mellem ribbeetagplader (RTP), hvor også den skivevirkning udnyttes. Vaflen har gode...

  10. Spectral invariance hypothesis study of polarized reflectance with Ground-based Multiangle SpectroPolarimetric Imager (GroundMSPI)

    Science.gov (United States)

    Bradley, Christine L.; Kupinski, Meredith; Diner, David J.; Xu, Feng; Chipman, Russell A.

    2015-09-01

    Many models used to represent the boundary condition for the separation of atmospheric scattering from the surface reflectance in polarized remote sensing measurements assume that the polarized surface reflectance is spectrally neutral. The Spectral Invariance Hypothesis asserts that the magnitude and shape of the polarized bidirectional reflectance factor (pBRF) is equal for all wavelengths. In order to test this hypothesis, JPL's Ground-based Multiangle SpectroPolarimetric Imager (GroundMSPI) is used to measure polarization information of different outdoor surface types. GroundMSPI measures the linear polarization Stokes parameters (I, Q, U), at three wavelengths, 470 nm, 660 nm, and 865 nm. The camera is mounted on a two-axis gimbal to accurately select the view azimuth and elevation directions. On clear sky days we acquired day-long scans of scenes that contain various surface types such as grass, dirt, cement, brick, and asphalt and placed a Spectralon panel in the camera field of view to provide a reflectance reference. Over the course of each day, changing solar position in the sky provides a large range of scattering angles for this study. The polarized bidirectional reflectance factor (pBRF) is measured for the three wavelengths and the best fit slope of the spectral correlation is reported. This work reports the range of best fit slopes measured for five region types.

  11. Response of base isolation system excited by spectrum compatible ground motions

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jung Han; Kim, Min Kyu; Choi, In Kil [KAERI, Daejeon (Korea, Republic of)

    2012-10-15

    Structures in a nuclear power system are designed to be elastic even under an earthquake excitation. However a structural component such as an isolator shows inelastic behavior inherently. For the seismic assessment of nonlinear structures, the response history analysis should be performed. Especially for the performance based design, where the failure probability of a system needs to be evaluated, the variation of response should be evaluated. In this study, the spectrum compatible ground motions, the artificial ground motion and the modified ground motion, were generated. Using these ground motions, the variations of seismic responses of a simplified isolation system were evaluated.

  12. (Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio)

    Energy Technology Data Exchange (ETDEWEB)

    1992-03-01

    This report presents information related to the sampling of ground water at the Wright-Patterson Air Force Base. It is part of an investigation into possible ground water contamination. Information concerns well drilling/construction; x-ray diffraction and sampling; soil boring logs; and chain-of-custody records.

  13. A knowledge base system for ground control over abandoned mines

    Energy Technology Data Exchange (ETDEWEB)

    Nazimko, V.V.; Zviagilsky, E.L. [Donetsk State Technical University, Donetsk (Ukraine)

    1999-07-01

    The knowledge of engineering systems has been developed to choose optimal technology for subsidence prevention over abandoned mines. The expert system treats a specific case, maps consequences of actions and derives relevant technology (or a set of technologies) that should be used to prevent ground subsidence. Input parameters that characterise the case are treated using fuzzy logic and are then fed to a neural network. The network has been successfully trained by a backpropagation algorithm on the basis of three fuzzy rules. 5 refs., 2 figs., 3 tabs.

  14. Ground-based measurement of surface temperature and thermal emissivity

    Science.gov (United States)

    Owe, M.; Van De Griend, A. A.

    1994-01-01

    Motorized cable systems for transporting infrared thermometers have been used successfully during several international field campaigns. Systems may be configured with as many as four thermal sensors up to 9 m above the surface, and traverse a 30 m transect. Ground and canopy temperatures are important for solving the surface energy balance. The spatial variability of surface temperature is often great, so that averaged point measurements result in highly inaccurate areal estimates. The cable systems are ideal for quantifying both temporal and spatial variabilities. Thermal emissivity is also necessary for deriving the absolute physical temperature, and measurements may be made with a portable measuring box.

  15. Commercial off the Shelf Ground Control Supports Calibration and Conflation from Ground to Space Based Sensors

    Science.gov (United States)

    Danielová, M.; Hummel, P.

    2016-06-01

    The need for rapid deployment of aerial and satellite imagery in support of GIS and engineering integration projects require new sources of geodetic control to ensure the accuracy for geospatial projects. In the past, teams of surveyors would need to deploy to project areas to provide targeted or photo identifiable points that are used to provide data for orthorecificaion, QA/QC and calibration for multi-platform sensors. The challenge of integrating street view, UAS, airborne and Space based sensors to produce the common operational picture requires control to tie multiple sources together. Today commercial off the shelf delivery of existing photo identifiable control is increasing the speed of deployment of this data without having to revisit sites over and over again. The presentation will discuss the processes developed by CompassData to build a global library of 40,000 control points available today. International Organization for Standardization (ISO) based processes and initiatives ensure consistent quality of survey data, photo identifiable features selected and meta data to support photogrammetrist, engineers and GIS professionals to quickly deliver projects with better accuracy.

  16. Principle and Design of a Single-phase Inverter Based Grounding System for Neutral-to-ground Voltage Compensation in Distribution Networks

    DEFF Research Database (Denmark)

    Wang, Wen; Yan, Lingjie; Zeng, Xiangjun

    2017-01-01

    Neutral-to-ground overvoltage may occur in non-effectively grounded power systems because of the distributed parameters asymmetry and resonance between Petersen coil and distributed capacitances. Thus, the constraint of neutral-to-ground voltage is critical for the safety of distribution networks....... In this paper, an active grounding system based on single-phase inverter and its control parameter design method is proposed to achieve this objective. Relationship between its output current and neutral-to-ground voltage is derived to explain the principle of neutral-to-ground voltage compensation. Then...... margin subjecting to large range of load change. The PI method is taken as the comparative method and the performances of both control methods are presented in detail. Experimental results prove the effectiveness and novelty of the proposed grounding system and control method....

  17. Simultaneous ground- and satellite-based observation of MF/HF auroral radio emissions

    Science.gov (United States)

    Sato, Yuka; Kumamoto, Atsushi; Katoh, Yuto; Shinbori, Atsuki; Kadokura, Akira; Ogawa, Yasunobu

    2016-05-01

    We report on the first simultaneous measurements of medium-high frequency (MF/HF) auroral radio emissions (above 1 MHz) by ground- and satellite-based instruments. Observational data were obtained by the ground-based passive receivers in Iceland and Svalbard, and by the Plasma Waves and Sounder experiment (PWS) mounted on the Akebono satellite. We observed two simultaneous appearance events, during which the frequencies of the auroral roar and MF bursts detected at ground level were different from those of the terrestrial hectometric radiation (THR) observed by the Akebono satellite passing over the ground-based stations. This frequency difference confirms that auroral roar and THR are generated at different altitudes across the F peak. We did not observe any simultaneous observations that indicated an identical generation region of auroral roar and THR. In most cases, MF/HF auroral radio emissions were observed only by the ground-based detector, or by the satellite-based detector, even when the satellite was passing directly over the ground-based stations. A higher detection rate was observed from space than from ground level. This can primarily be explained in terms of the idea that the Akebono satellite can detect THR emissions coming from a wider region, and because a considerable portion of auroral radio emissions generated in the bottomside F region are masked by ionospheric absorption and screening in the D/E regions associated with ionization which results from auroral electrons and solar UV radiation.

  18. Space- and ground-based particle physics meet at CERN

    CERN Document Server

    CERN Bulletin

    2012-01-01

    The fourth international conference on Particle and Fundamental Physics in Space (SpacePart12) will take place at CERN from 5 to 7 November. The conference will bring together scientists working on particle and fundamental physics in space and on ground, as well as space policy makers from around the world.   One hundred years after Victor Hess discovered cosmic rays using hot air balloons, the experimental study of particle and fundamental physics is still being pursued today with extremely sophisticated techniques: on the ground, with state-of-the-art accelerators like the LHC; and in space, with powerful observatories that probe, with amazing accuracy, the various forms of cosmic radiation, charged and neutral, which are messengers of the most extreme conditions of matter and energy. SpacePart12 will be the opportunity for participants to exchange views on the progress of space-related science and technology programmes in the field of particle and fundamental physics in space. SpacePar...

  19. A novel technique for extracting clouds base height using ground based imaging

    Directory of Open Access Journals (Sweden)

    E. Hirsch

    2011-01-01

    Full Text Available The height of a cloud in the atmospheric column is a key parameter in its characterization. Several remote sensing techniques (passive and active, either ground-based or on space-borne platforms and in-situ measurements are routinely used in order to estimate top and base heights of clouds. In this article we present a novel method that combines thermal imaging from the ground and sounded wind profile in order to derive the cloud base height. This method is independent of cloud types, making it efficient for both low boundary layer and high clouds. In addition, using thermal imaging ensures extraction of clouds' features during daytime as well as at nighttime. The proposed technique was validated by comparison to active sounding by ceilometers (which is a standard ground based method, to lifted condensation level (LCL calculations, and to MODIS products obtained from space. As all passive remote sensing techniques, the proposed method extracts only the height of the lowest cloud layer, thus upper cloud layers are not detected. Nevertheless, the information derived from this method can be complementary to space-borne cloud top measurements when deep-convective clouds are present. Unlike techniques such as LCL, this method is not limited to boundary layer clouds, and can extract the cloud base height at any level, as long as sufficient thermal contrast exists between the radiative temperatures of the cloud and its surrounding air parcel. Another advantage of the proposed method is its simplicity and modest power needs, making it particularly suitable for field measurements and deployment at remote locations. Our method can be further simplified for use with visible CCD or CMOS camera (although nighttime clouds will not be observed.

  20. Ground-Based Lidar Measurements During the CALIPSO and Twilight Zone (CATZ) Campaign

    Science.gov (United States)

    Berkoff, Timothy; Qian, Li; Kleidman, Richard; Stewart, Sebastian; Welton, Ellsworth; Li, Zhu; Holbem, Brent

    2008-01-01

    The CALIPSO and Twilight Zone (CATZ) field campaign was carried out between June 26th and August 29th of 2007 in the multi-state Maryland-Virginia-Pennsylvania region of the U.S. to study aerosol properties and cloud-aerosol interactions during overpasses of the CALIPSO satellite. Field work was conducted on selected days when CALIPSO ground tracks occurred in the region. Ground-based measurements included data from multiple Cimel sunphotometers that were placed at intervals along a segment of the CALIPSO ground-track. These measurements provided sky radiance and AOD measurements to enable joints inversions and comparisons with CALIPSO retrievals. As part of this activity, four ground-based lidars provided backscatter measurements (at 523 nm) in the region. Lidars at University of Maryland Baltimore County (Catonsville, MD) and Goddard Space Flight Center (Greenbelt, MD) provided continuous data during the campaign, while two micro-pulse lidar (MPL) systems were temporarily stationed at various field locations directly on CALIPSO ground-tracks. As a result, thirteen on-track ground-based lidar observations were obtained from eight different locations in the region. In some cases, nighttime CALIPSO coincident measurements were also obtained. In most studies reported to date, ground-based lidar validation efforts for CALIPSO rely on systems that are at fixed locations some distance away from the satellite ground-track. The CATZ ground-based lidar data provide an opportunity to examine vertical structure properties of aerosols and clouds both on and off-track simultaneously during a CALIPSO overpass. A table of available ground-based lidar measurements during this campaign will be presented, along with example backscatter imagery for a number of coincident cases with CALIPSO. Results indicate that even for a ground-based measurements directly on-track, comparisons can still pose a challenge due to the differing spatio-temporal properties of the ground and satellite

  1. Improving the detection of explosive hazards with LIDAR-based ground plane estimation

    Science.gov (United States)

    Buck, A.; Keller, J. M.; Popescu, M.

    2016-05-01

    Three-dimensional point clouds generated by LIDAR offer the potential to build a more complete understanding of the environment in front of a moving vehicle. In particular, LIDAR data facilitates the development of a non-parametric ground plane model that can filter target predictions from other sensors into above-ground and below-ground sets. This allows for improved detection performance when, for example, a system designed to locate above-ground targets considers only the set of above-ground predictions. In this paper, we apply LIDAR-based ground plane filtering to a forward looking ground penetrating radar (FLGPR) sensor system and a side looking synthetic aperture acoustic (SAA) sensor system designed to detect explosive hazards along the side of a road. Additionally, we consider the value of the visual magnitude of the LIDAR return as a feature for identifying anomalies. The predictions from these sensors are evaluated independently with and without ground plane filtering and then fused to produce a combined prediction confidence. Sensor fusion is accomplished by interpolating the confidence scores of each sensor along the ground plane model to create a combined confidence vector at specified points in the environment. The methods are tested along an unpaved desert road at an arid U.S. Army test site.

  2. Microcontroller based ground weapon control system(Short Communication

    Directory of Open Access Journals (Sweden)

    M. Sankar Kishore

    2001-10-01

    Full Text Available Armoured vehicles and tanks generally consist of high resolution optical (both infrared and visible and display systems for recognition and identification of the targets. Different weapons/articles to engage the targets may be present. A fire control system (FCS controls all the above systems, monitors the status of the articles present and passes the information to the display system. Depending upon the health and availability of the articles, the FCS selects and fires the articles. Design and development of ground control unit which is the heart of the FCS, both in hardware and software, has been emphasised. The system has been developed using microcontroller and software developed in ASM 51 language. The system also has a facility to test all the systems and articles as initial power on condition. From the safety point of view, software and hardware interlocks have been provided in the critical operations, like firing sequence. "

  3. (Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio)

    Energy Technology Data Exchange (ETDEWEB)

    1991-10-01

    This report presents information concerning field procedures employed during the monitoring, well construction, well purging, sampling, and well logging at the Wright-Patterson Air Force Base. Activities were conducted in an effort to evaluate ground water contamination.

  4. Ground-based Infrared Observations of Water Vapor and Hydrogen Peroxide in the Atmosphere of Mars

    Science.gov (United States)

    Encrenaz, T.; Greathouse, T. K.; Bitner, M.; Kruger, A.; Richter, M. J.; Lacy, J. H.; Bézard, B.; Fouchet, T.; Lefevre, F.; Forget, F.; Atreya, S. K.

    2008-11-01

    Ground-based observations of water vapor and hydrogen peroxide have been obtained in the thermal infrared range, using the TEXES instrument at the NASA Infrared Telescope Facility, for different times of the seasonal cycle.

  5. Informing hydrological models with ground-based time-lapse relative gravimetry: potential and limitations

    DEFF Research Database (Denmark)

    Bauer-Gottwein, Peter; Christiansen, Lars; Rosbjerg, Dan

    2011-01-01

    Coupled hydrogeophysical inversion emerges as an attractive option to improve the calibration and predictive capability of hydrological models. Recently, ground-based time-lapse relative gravity (TLRG) measurements have attracted increasing interest because there is a direct relationship between ...

  6. Changes in ground-based solar ultraviolet radiation during fire episodes: a case study

    CSIR Research Space (South Africa)

    Wright, CY

    2013-09-01

    Full Text Available about the relationship between fires and solar UVR without local high-quality column or ground-based ambient air pollution (particulate matter in particular) data; however, the threat to public health from fires was acknowledged....

  7. Spectrally selective surfaces for ground and space-based instrumentation: support for a resource base

    Science.gov (United States)

    McCall, Susan H.; Sinclair, R. Lawrence; Pompea, Stephen M.; Breault, Robert P.

    1993-11-01

    The performance of space telescopes, space instruments, and space radiator systems depends critically upon the selection of appropriate spectrally selective surfaces. Many space programs have suffered severe performance limitations, schedule setbacks, and spent hundreds of thousands of dollars in damage control because of a lack of readily-accessible, accurate data on the properties of spectrally selective surfaces, particularly black surfaces. A Canadian effort is underway to develop a resource base (database and support service) to help alleviate this problem. The assistance of the community is required to make the resource base comprehensive and useful to the end users. The paper aims to describe the objectives of this project. In addition, a request for information and support is made for various aspects of the project. The resource base will be useful for both ground and space-based instrumentation.

  8. System Identification and Automatic Mass Balancing of Ground-Based Three-Axis Spacecraft Simulator

    Science.gov (United States)

    2006-08-01

    System Identification and Automatic Mass Balancing of Ground-Based Three-Axis Spacecraft Simulator Jae-Jun Kim∗ and Brij N. Agrawal † Department of...TITLE AND SUBTITLE System Identification and Automatic Mass Balancing of Ground-Based Three-Axis Spacecraft Simulator 5a. CONTRACT NUMBER 5b...and Dynamics, Vol. 20, No. 4, July-August 1997, pp. 625-632. 6Schwartz, J. L. and Hall, C. D., “ System Identification of a Spherical Air-Bearing

  9. Ground-based hyperspectral analysis of the urban nightscape

    Science.gov (United States)

    Alamús, Ramon; Bará, Salvador; Corbera, Jordi; Escofet, Jaume; Palà, Vicenç; Pipia, Luca; Tardà, Anna

    2017-02-01

    Airborne hyperspectral cameras provide the basic information to estimate the energy wasted skywards by outdoor lighting systems, as well as to locate and identify their sources. However, a complete characterization of the urban light pollution levels also requires evaluating these effects from the city dwellers standpoint, e.g. the energy waste associated to the excessive illuminance on walls and pavements, light trespass, or the luminance distributions causing potential glare, to mention but a few. On the other hand, the spectral irradiance at the entrance of the human eye is the primary input to evaluate the possible health effects associated with the exposure to artificial light at night, according to the more recent models available in the literature. In this work we demonstrate the possibility of using a hyperspectral imager (routinely used in airborne campaigns) to measure the ground-level spectral radiance of the urban nightscape and to retrieve several magnitudes of interest for light pollution studies. We also present the preliminary results from a field campaign carried out in the downtown of Barcelona.

  10. Figure-ground organization based on three-dimensional symmetry

    Science.gov (United States)

    Michaux, Aaron; Jayadevan, Vijai; Delp, Edward; Pizlo, Zygmunt

    2016-11-01

    We present an approach to figure/ground organization using mirror symmetry as a general purpose and biologically motivated prior. Psychophysical evidence suggests that the human visual system makes use of symmetry in producing three-dimensional (3-D) percepts of objects. 3-D symmetry aids in scene organization because (i) almost all objects exhibit symmetry, and (ii) configurations of objects are not likely to be symmetric unless they share some additional relationship. No general purpose approach is known for solving 3-D symmetry correspondence in two-dimensional (2-D) camera images, because few invariants exist. Therefore, we present a general purpose method for finding 3-D symmetry correspondence by pairing the problem with the two-view geometry of the binocular correspondence problem. Mirror symmetry is a spatially global property that is not likely to be lost in the spatially local noise of binocular depth maps. We tested our approach on a corpus of 180 images collected indoors with a stereo camera system. K-means clustering was used as a baseline for comparison. The informative nature of the symmetry prior makes it possible to cluster data without a priori knowledge of which objects may appear in the scene, and without knowing how many objects there are in the scene.

  11. DATA PROCESSING AND ANALYSIS TOOLS BASED ON GROUND-BASED SYNTHETIC APERTURE RADAR IMAGERY

    Directory of Open Access Journals (Sweden)

    M. Crosetto

    2017-09-01

    Full Text Available The Ground-Based SAR (GBSAR is a terrestrial remote sensing technique used to measure and monitor deformation. In this paper we describe two complementary approaches to derive deformation measurements using GBSAR data. The first approach is based on radar interferometry, while the second one exploits the GBSAR amplitude. In this paper we consider the so-called discontinuous GBSAR acquisition mode. The interferometric process is not always straightforward: it requires appropriate data processing and analysis tools. One of the main critical steps is phase unwrapping, which can critically affect the deformation measurements. In this paper we describe the procedure used at the CTTC to process and analyse discontinuous GBSAR data. In the second part of the paper we describe the approach based on GBSAR amplitude images and an image-matching method.

  12. Cloud Base Height and Effective Cloud Emissivity Retrieval with Ground-Based Infrared Interferometer

    Institute of Scientific and Technical Information of China (English)

    PAN Lin-Jun; LU Da-Ren

    2012-01-01

    Based on ground-based Atmospheric Emitted Radiance Interferometer (AERI) observations in Shouxian, Anhui province, China, the authors retrieve the cloud base height (CBH) and effective cloud emissivity by using the minimum root-mean-square difference method. This method was originally developed for satellite remote sensing. The high-temporal-resolution retrieval results can depict the trivial variations of the zenith clouds continu- ously. The retrieval results are evaluated by comparing them with observations by the cloud radar. The compari- son shows that the retrieval bias is smaller for the middle and low cloud, especially for the opaque cloud. When two layers of clouds exist, the retrieval results reflect the weighting radiative contribution of the multi-layer cloud. The retrieval accuracy is affected by uncertainties of the AERI radiances and sounding profiles, in which the role of uncertainty in the temperature profile is dominant.

  13. GROUND FILTERING LiDAR DATA BASED ON MULTI-SCALE ANALYSIS OF HEIGHT DIFFERENCE THRESHOLD

    Directory of Open Access Journals (Sweden)

    P. Rashidi

    2017-09-01

    Full Text Available Separating point clouds into ground and non-ground points is a necessary step to generate digital terrain model (DTM from LiDAR dataset. In this research, a new method based on multi-scale analysis of height difference threshold is proposed for ground filtering of LiDAR data. The proposed method utilizes three windows with different sizes in small, average and large to cover the entire LiDAR point clouds, then with a height difference threshold, point clouds can be separated to ground and non-ground in each local window. Meanwhile, the best threshold values for size of windows are considered based on physical characteristics of the ground surface and size of objects. Also, the minimum of height of object in each window selected as height difference threshold. In order to evaluate the performance of the proposed algorithm, two datasets in rural and urban area were applied. The overall accuracy in rural and urban area was 96.06% and 94.88% respectively. These results of the filtering showed that the proposed method can successfully filters non-ground points from LiDAR point clouds despite of the data area.

  14. Low Power Ground-Based Laser Illumination for Electric Propulsion Applications

    Science.gov (United States)

    Lapointe, Michael R.; Oleson, Steven R.

    1994-01-01

    A preliminary evaluation of low power, ground-based laser powered electric propulsion systems is presented. A review of available and near-term laser, photovoltaic, and adaptive optic systems indicates that approximately 5-kW of ground-based laser power can be delivered at an equivalent one-sun intensity to an orbit of approximately 2000 km. Laser illumination at the proper wavelength can double photovoltaic array conversion efficiencies compared to efficiencies obtained with solar illumination at the same intensity, allowing a reduction in array mass. The reduced array mass allows extra propellant to be carried with no penalty in total spacecraft mass. The extra propellant mass can extend the satellite life in orbit, allowing additional revenue to be generated. A trade study using realistic cost estimates and conservative ground station viewing capability was performed to estimate the number of communication satellites which must be illuminated to make a proliferated system of laser ground stations economically attractive. The required number of satellites is typically below that of proposed communication satellite constellations, indicating that low power ground-based laser beaming may be commercially viable. However, near-term advances in low specific mass solar arrays and high energy density batteries for LEO applications would render the ground-based laser system impracticable.

  15. Designed microtremor array based actual measurement and analysis of strong ground motion at Palu city, Indonesia

    Science.gov (United States)

    Thein, Pyi Soe; Pramumijoyo, Subagyo; Brotopuspito, Kirbani Sri; Wilopo, Wahyu; Kiyono, Junji; Setianto, Agung; Putra, Rusnardi Rahmat

    2015-04-01

    In this study, we investigated the strong ground motion characteristics under Palu City, Indonesia. The shear wave velocity structures evaluated by eight microtremors measurement are the most applicable to determine the thickness of sediments and average shear wave velocity with Vs ≤ 300 m/s. Based on subsurface underground structure models identified, earthquake ground motion was estimated in the future Palu-Koro earthquake by using statistical green's function method. The seismic microzonation parameters were carried out by considering several significant controlling factors on ground response at January 23, 2005 earthquake.

  16. Designed microtremor array based actual measurement and analysis of strong ground motion at Palu city, Indonesia

    Energy Technology Data Exchange (ETDEWEB)

    Thein, Pyi Soe, E-mail: pyisoethein@yahoo.com [Geology Department, Yangon University (Myanmar); Pramumijoyo, Subagyo; Wilopo, Wahyu; Setianto, Agung [Geological Engineering Department, Gadjah Mada University (Indonesia); Brotopuspito, Kirbani Sri [Physics Department, Gadjah Mada University (Indonesia); Kiyono, Junji; Putra, Rusnardi Rahmat [Graduate School of Global Environmental Studies, Kyoto University (Japan)

    2015-04-24

    In this study, we investigated the strong ground motion characteristics under Palu City, Indonesia. The shear wave velocity structures evaluated by eight microtremors measurement are the most applicable to determine the thickness of sediments and average shear wave velocity with Vs ≤ 300 m/s. Based on subsurface underground structure models identified, earthquake ground motion was estimated in the future Palu-Koro earthquake by using statistical green’s function method. The seismic microzonation parameters were carried out by considering several significant controlling factors on ground response at January 23, 2005 earthquake.

  17. Establishing common ground in community-based arts in health.

    Science.gov (United States)

    White, Mike

    2006-05-01

    This article originates in current research into community-based arts in health. Arts in health is now a diverse field of practice, and community-based arts in health interventions have extended the work beyond healthcare settings into public health. Examples of this work can now be found internationally in different health systems and cultural contexts. The paper argues that researchers need to understand the processes through which community-based arts in health projects evolve, and how they work holistically in their attempt to produce therapeutic and social benefits for both individuals and communities, and to connect with a cultural base in healthcare services themselves. A development model that might be adapted to assist in analysing this is the World Health Organisation Quality of Life Index (WHOQOL). Issues raised in the paper around community engagement, healthy choice and self-esteem are then illustrated in case examples of community-based arts in health practice in South Africa and England; namely the DramAide and Siyazama projects in KwaZulu-Natal, and Looking Well Healthy Living Centre in North Yorkshire. In South Africa there are arts and media projects attempting to raise awareness about HIV/AIDS through mass messaging, but they also recognize that they lack models of longer-term community engagement. Looking Well by contrast addresses health issues identified by the community itself in ways that are personal, empathic and domesticated. But there are also similarities among these projects in their aims to generate a range of social, educational and economic benefits within a community-health framework, and they are successfully regenerating traditional cultural forms to create public participation in health promotion. Process evaluation may provide a framework in which community-based arts in health projects, especially if they are networked together to share practice and thinking, can assess their ability to address health inequalities and focus

  18. Analysis of meteorological variables in the Australasian region using ground- and space-based GPS techniques

    Science.gov (United States)

    Kuleshov, Yuriy; Choy, Suelynn; Fu, Erjiang Frank; Chane-Ming, Fabrice; Liou, Yuei-An; Pavelyev, Alexander G.

    2016-07-01

    Results of analysis of meteorological variables (temperature and moisture) in the Australasian region using the global positioning system (GPS) radio occultation (RO) and GPS ground-based observations verified with in situ radiosonde (RS) data are presented. The potential of using ground-based GPS observations for retrieving column integrated precipitable water vapour (PWV) over the Australian continent has been demonstrated using the Australian ground-based GPS reference stations network. Using data from the 15 ground-based GPS stations, the state of the atmosphere over Victoria during a significant weather event, the March 2010 Melbourne storm, has been investigated, and it has been shown that the GPS observations has potential for monitoring the movement of a weather front that has sharp moisture contrast. Temperature and moisture variability in the atmosphere over various climatic regions (the Indian and the Pacific Oceans, the Antarctic and Australia) has been examined using satellite-based GPS RO and in situ RS observations. Investigating recent atmospheric temperature trends over Antarctica, the time series of the collocated GPS RO and RS data were examined, and strong cooling in the lower stratosphere and warming through the troposphere over Antarctica has been identified, in agreement with outputs of climate models. With further expansion of the Global Navigation Satellite Systems (GNSS) system, it is expected that GNSS satellite- and ground-based measurements would be able to provide an order of magnitude larger amount of data which in turn could significantly advance weather forecasting services, climate monitoring and analysis in the Australasian region.

  19. Ground-Based Surveillance and Tracking System (GSTS)

    Science.gov (United States)

    1987-08-01

    reported availabilty of relatively high- paying jobs. The consequences of increased migration could be significant. No significant impacts at U.S. Army...Air Force Base are contributing to overdrawing the aquifers, and at current usage rates the aquifers could be depleted (44). The "Draft Environmental

  20. Tracking of urban aerosols using combined lidar-based remote sensing and ground-based measurements

    Directory of Open Access Journals (Sweden)

    T.-Y. He

    2011-10-01

    Full Text Available A measuring campaign was performed over the neighboring towns of Nova Gorica in Slovenia and Gorizia in Italy on 24 and 25 May 2010, to investigate the concentration and distribution of urban aerosols. Tracking of two-dimensional spatial and temporal aerosol distributions was performed using scanning elastic lidar operating at 1064 nm. In addition, PM10 concentrations of particles, NOx and meteorological data were continuously monitored within the lidar scanning region. Based on the collected data, we investigated the flow dynamics and the aerosol concentrations within the lower troposphere and an evidence for daily aerosol cycles. We observed a number of cases with spatially localized increased lidar returns, which were found to be due to the presence of point sources of particulate matter. Daily aerosol concentration cycles were also clearly visible with a peak in aerosol concentration during the morning rush hours and daily maximum at around 17:00 Central European Time. We also found that the averaged horizontal atmospheric extinction within the scanning region 200 m above the ground is correlated to the PM10 concentration at the ground level with a correlation coefficient of 0.64, which may be due to relatively quiet meteorological conditions and basin-like terrain configuration.

  1. Ground Based GPS Phase Measurements for Atmospheric Sounding

    Science.gov (United States)

    2016-06-14

    based GPS observations for the correction of radar observations. 6 REFERENCES Alber, C., R. Ware, C. Rocken, and J. Braun, A new method for sensing ...rocken@ucar.edu Award #: N00014-97-1-0258 LONG-TERM GOAL The goal is to develop GPS remote sensing techniques to determine atmospheric signal delay and...agrees best with the observations in a least squares sense is selected. The corresponding refractivity profile is then selected. • We tested this

  2. Constraint-based Ground contact handling in Humanoid Robotics Simulation

    OpenAIRE

    Martin Moraud, Eduardo; Hale, Joshua G.; Cheng, Gordon

    2008-01-01

    International audience; This paper presents a method for resolving contact in dynamic simulations of articulated figures. It is intended for humanoids with polygonal feet and incorporates Coulomb friction exactly. The proposed technique is based on a constraint selection paradigm. Its implementation offers an exact mode which guarantees correct behavior, as well as an efficiency optimized mode which sacrifices accuracy for a tightly bounded computational burden, thus facilitating batch simula...

  3. Ground-based follow-up in relation to Kepler Asteroseismic Investigation

    CERN Document Server

    Uytterhoeven, K; Bruntt, H; De Cat, P; Frandsen, S; Gutierrez-Soto, J; Kiss, L; Kurtz, D W; Marconi, M; Molenda-Zakowicz, J; Ostensen, R; Randall, S; Southworth, J; Szabo, R

    2010-01-01

    The Kepler space mission, successfully launched in March 2009, is providing continuous, high-precision photometry of thousands of stars simultaneously. The uninterrupted time-series of stars of all known pulsation types are a precious source for asteroseismic studies. The Kepler data do not provide information on the physical parameters, such as effective temperature, surface gravity, metallicity, and vsini, which are crucial for successful asteroseismic modelling. Additional ground-based time-series data are needed to characterize mode parameters in several types of pulsating stars. Therefore, ground-based multi-colour photometry and mid/high-resolution spectroscopy are needed to complement the space data. We present ground-based activities within KASC on selected asteroseismic Kepler targets of several pulsation types. (Based on observations made with the Isaac Newton Telescope, William Herschel Telescope, Nordic Optical Telescope, Telescopio Nazionale Galileo, Mercator Telescope (La Palma, Spain), and IAC-...

  4. Ka-band bistatic ground-based SAR using noise signals

    Science.gov (United States)

    Lukin, K.; Mogyla, A.; Vyplavin, P.; Palamarchuk, V.; Zemlyaniy, O.; Tarasenko, V.; Zaets, N.; Skretsanov, V.; Shubniy, A.; Glamazdin, V.; Natarov, M.; Nechayev, O.

    2008-01-01

    Currently, one of the actual problems is remote monitoring of technical state of large objects. Different methods can be used for that purpose. The most promising of them relies on application of ground based synthetic aperture radars (SAR) and differential interferometry. We have designed and tested Ground Based Noise Waveform SAR based on noise radar technology [1] and synthetic aperture antennas [2]. It enabled to build an instrument for precise all-weather monitoring of large objects in real-time. We describe main performance of ground-based interferometric SAR which uses continuous Ka-band noise waveform as a probe signal. Besides, results of laboratory trials and evaluation of its main performance are presented as well.

  5. Analysis of English Complex Sentences based on Figure-Ground Theory

    Institute of Scientific and Technical Information of China (English)

    侯皓

    2015-01-01

    English is a language featuring its complex sentences composed of main and sub-ordinate clauses. The subordinate clause conveys the unifnished messages in main clause and it becomes quite complicated. English complex sentence is a fair impor-tant sentence type and also of importance in English teaching. Analyzing complex sentence based on Figure-Ground Theory, especially the Adverbial Clause, is help-ful to learn English and translate it. The Figure-Ground Theory originated in psychol-ogy studies and it was introduced in cognitive linguistics to explain some language phenomena. From Figure-Ground perspective, the essay studies attributive clause, adverbial clause and nominal clause and some critical sentence types have been analyzed carefully and the major ifnding is Figure-Ground Theory is dynamic not static.

  6. Novel identification strategy for ground coffee adulteration based on UPLC-HRMS oligosaccharide profiling.

    Science.gov (United States)

    Cai, Tie; Ting, Hu; Jin-Lan, Zhang

    2016-01-01

    Coffee is one of the most common and most valuable beverages. According to International Coffee Organization (ICO) reports, the adulteration of coffee for financial reasons is regarded as the most serious threat to the sustainable development of the coffee market. In this work, a novel strategy for adulteration identification in ground coffee was developed based on UPLC-HRMS oligosaccharide profiling. Along with integrated statistical analysis, 17 oligosaccharide composition were identified as markers for the identification of soybeans and rice in ground coffee. This strategy, validated by manual mixtures, optimized both the reliability and authority of adulteration identification. Rice and soybean adulterants present in ground coffee in amounts as low as 5% were identified and evaluated. Some commercial ground coffees were also successfully tested using this strategy.

  7. Coastal wind study based on Sentinel-1 and ground-based scanning lidar

    DEFF Research Database (Denmark)

    Ahsbahs, Tobias Torben; Badger, Merete; Pena Diaz, Alfredo

    , the project "Reducing the Uncertainty of Near-shore Energy estimates from meso- and micro-scale wind models" (RUNE) was established. The lidar measurement campaign started November 2015 and ended in February 2016 at the Danish North Sea coast at around 56.5 ◦N, 8.2 ◦E. 107 satellite SAR scenes were collected...... fields from the Sentinel-1A satellite using APL/NOAA’s SAROPS system with GFS model wind directions as input. For the presented cases CMOD5.n is used. Ground-based scanning lidar located on land can also cover near shore areas. In order to improve wind farm planning for near-shore coastal areas...

  8. Dust optical properties retrieved from ground-based polarimetric measurements.

    Science.gov (United States)

    Li, Zhengqiang; Goloub, Philippe; Blarel, Luc; Damiri, Bahaiddin; Podvin, Thierry; Jankowiak, Isabelle

    2007-03-20

    We have systematically processed one year of sunphotometer measurements (recorded at five AERONET/PHOTONS sites in Africa) in order to assess mineral dust optical properties with the use of a new polarimetry-based algorithm. We consider the Cimel CE318 polarized sunphotometer version to obtain single-scattering albedo, scattering phase matrix elements F(11) and F(12) for dust aerosols selected with Angström exponents ranging from -0.05 to 0.25. Retrieved F(11) and F(12) differ significantly from those of spherical particles. The degree of linear polarization -F(12)/F(11) for single scattering of atmospheric total column dust aerosols in the case of unpolarized incident light is systematically retrieved for the first time to our knowledge from sunphotometer measurements and shows consistency with previous laboratory characterizations of nonspherical particles.

  9. Analysis of the substorm trigger phase using multiple ground-based instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Kauristie, K.; Pulkkinen, T.I.; Pellinen, R.J. [Finnish Meteorological Institute, Helsinki (Finland)] [and others

    1995-08-01

    The authors discuss in detail the observation of an event of auroral activity fading during the trigger, or growth phase of a magnetic storm. This event was observed by all-sky cameras, EISCAT radar and magnetometers, riometers, and pulsation magnetometers, from ground based stations in Finland and Scandanavia. Based on their detailed analysis, they present a possible cause for the observed fading.

  10. Plans of a test bed for ionospheric modelling based on Fennoscandian ground-based instrumentation

    Science.gov (United States)

    Kauristie, Kirsti; Kero, Antti; Verronen, Pekka T.; Aikio, Anita; Vierinen, Juha; Lehtinen, Markku; Turunen, Esa; Pulkkinen, Tuija; Virtanen, Ilkka; Norberg, Johannes; Vanhamäki, Heikki; Kallio, Esa; Kestilä, Antti; Partamies, Noora; Syrjäsuo, Mikko

    2016-07-01

    One of the recommendations for teaming among research groups in the COSPAR/ILWS roadmap is about building test beds in which coordinated observing supports model development. In the presentation we will describe a test bed initiative supporting research on ionosphere-thermosphere-magnetosphere interactions. The EISCAT incoherent scatter radars with their future extension, EISCAT3D, form the backbone of the proposed system. The EISCAT radars are surrounded by versatile and dense arrays of ground-based instrumentation: magnetometers and auroral cameras (the MIRACLE and IMAGE networks), ionospheric tomography receivers (the TomoScand network) and other novel technology for upper atmospheric probing with radio waves (e.g. the KAIRA facility, riometers and the ionosonde maintained by the Sodankylä Geophysical Observatory). As a new opening, close coordination with the Finnish national cubesat program is planned. We will investigate opportunities to establish a cost efficient nanosatellite program which would support the ground-based observations in a systematic and persistent manner. First experiences will be gathered with the Aalto-1 and Aalto-2 satellites, latter of which will be the Finnish contribution to the international QB50 mission. We envisage close collaboration also in the development of data analysis tools with the goal to integrate routines and models from different research groups to one system, where the different elements support each other. In the longer run we are aiming for a modelling framework with observational guidance which gives a holistic description on ionosphere-thermosphere processes and this way enables reliable forecasts on upper atmospheric space weather activity.

  11. Comparing Aerosol Retrievals from Ground-Based Instruments at the Impact-Pm Field Campaign

    Science.gov (United States)

    Kupinski, M.; Bradley, C. L.; Kalashnikova, O. V.; Xu, F.; Diner, D. J.; Clements, C. B.; Camacho, C.

    2016-12-01

    Detection of aerosol types, components having different size and chemical composition, over urban areas is important for understanding their impact on health and climate. In particular, sustained contact with size-differentiated airborne particulate matter: PM10 and PM2.5 can lead to adverse health effects such as asthma attacks, heart and lung diseases, and premature mortality. Multi-angular polarimetric measurements have been advocated in recent years as an additional tool to better understand and retrieve the aerosol properties needed for improved predictions of aerosol impart on air quality and climate. We deployed the ground-based Multiangle SpectroPolarimetric Imager (GroundMSPI) for accurate spectropolarimetric and radiance measurements co-located with the AERONET CIMEL sun photometer and a Halo Doppler 18 m resolution lidar from San José State University at the Garland-Fresno Air Quality supersite in Fresno, CA on July 7 during the Imaging Polarimetric Assessment and Characterization of Tropospheric Particulate Matter (ImPACT-PM) field experiment. GroundMSPI sampled the atmospheric scattering phase function in and 90 degrees out of the principal plane every 15 minutes in an automated manner, utilizing the 2-axis gimbal mount in elevation and azimuth. The goal of this work is verify atmospheric measurement of GroundMSPI with the coincident CIMEL sun photometer and ground-based lidar. Diffuse-sky radiance measurements of GroundMSPI are compared with the CIMEL sun photometer throughout the day. AERONET aerosol parameters such as size, shape, and index of refraction as well as lidar aerosol extinction profiles will be used in a forward radiative transfer model to compare with GroundMSPI observations and optimize these parameters to best match GroundMSPI data.

  12. Tracing ground water input to base flow using sulfate (S, O) isotopes.

    Science.gov (United States)

    Gu, Ailiang; Gray, Floyd; Eastoe, Christopher J; Norman, Laura M; Duarte, Oscar; Long, Austin

    2008-01-01

    Sulfate (S and O) isotopes used in conjunction with sulfate concentration provide a tracer for ground water contributions to base flow. They are particularly useful in areas where rock sources of contrasting S isotope character are juxtaposed, where water chemistry or H and O isotopes fail to distinguish water sources, and in arid areas where rain water contributions to base flow are minimal. Sonoita Creek basin in southern Arizona, where evaporite and igneous sources of sulfur are commonly juxtaposed, serves as an example. Base flow in Sonoita Creek is a mixture of three ground water sources: A, basin ground water with sulfate resembling that from Permian evaporite; B, ground water from the Patagonia Mountains; and C, ground water associated with Temporal Gulch. B and C contain sulfate like that of acid rock drainage in the region but differ in sulfate content. Source A contributes 50% to 70%, with the remainder equally divided between B and C during the base flow seasons. The proportion of B generally increases downstream. The proportion of A is greatest under drought conditions.

  13. Tracing ground water input to base flow using sulfate (S, O) isotopes

    Science.gov (United States)

    Gu, A.; Gray, F.; Eastoe, C.J.; Norman, L.M.; Duarte, O.; Long, A.

    2008-01-01

    Sulfate (S and O) isotopes used in conjunction with sulfate concentration provide a tracer for ground water contributions to base flow. They are particularly useful in areas where rock sources of contrasting S isotope character are juxtaposed, where water chemistry or H and O isotopes fail to distinguish water sources, and in arid areas where rain water contributions to base flow are minimal. Sonoita Creek basin in southern Arizona, where evaporite and igneous sources of sulfur are commonly juxtaposed, serves as an example. Base flow in Sonoita Creek is a mixture of three ground water sources: A, basin ground water with sulfate resembling that from Permian evaporite; B, ground water from the Patagonia Mountains; and C, ground water associated with Temporal Gulch. B and C contain sulfate like that of acid rock drainage in the region but differ in sulfate content. Source A contributes 50% to 70%, with the remainder equally divided between B and C during the base flow seasons. The proportion of B generally increases downstream. The proportion of A is greatest under drought conditions.

  14. A framework for recovery-oriented, COTS-based ground station networks

    Science.gov (United States)

    Cutler, James William

    The complexity of space communication has limited our access to space systems and kept mission operations costs high. Ultimately, this results in reduced mission capabilities and yields. In particular, ground stations, the access point between space and terrestrial networks, suffer from monolithic designs, narrow interfaces, and unreliability that raise significant financial barriers for low-cost, experimental satellite missions. This research reduces these barriers by developing technology for recovery-oriented, flexible access networks built from commercial-off-the-shelf (COTS) components. Based on our extensive small satellite experiences, we decomposed ground station services and captured them in an extensible framework that simplified reuse of ground station services and improved portability across heterogeneous installations. This capability, combined with selective customization through virtual machine technology, allowed us to deliver "just in time" ground stations for QuakeSat-1 at a fraction of the price of current commodity solutions. This decomposition is also informed by principles of robust system design. Thus, our ground station reference implementation called Mercury was a candidate for recursive recovery (RR), a high availability technique whose effectiveness in reducing recovery time has been demonstrated on research prototypes of Internet server systems. Augmenting Mercury to implement RR reduced recovery time of typical ground station software failures by a factor of four, dropping recovery time to within the "window of recovery" and effectively eliminating the adverse effects of these failures. Since the time of failures cannot be predicted, RR allowed us to mitigate the effects of the failures and greatly reduce their potential impact on ground station operations. Our ground station architecture harnessed the benefits of COTS components, including rapid prototyping and deployment, while overcoming the challenges of COTS reliability and mission

  15. A New Method of Desired Gait Synthesis for Biped Walking Robot Based on Ground Reaction Force

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A new method of desired gait synthesis for biped walking robot based on the ground reaction force was proposed. The relation between the ground reaction force and joint motion is derived using the D'Almbert principle. In view of dynamic walking with high stability, the ZMP(Zero Moment Point)stability criterion must be considered in the desired gait synthesis. After that, the joint trajectories of biped walking robot are decided by substituting the ground reaction force into the aforesaid relation based on the ZMP criterion. The trajectory of desired ZMP is determined by a fuzzy logic based upon the body posture of biped walking robot. The proposed scheme is simulated and experimented on a 10 degree of freedom biped walking robot. The results indicate that the proposed method is feasible.

  16. BigBOSS: The Ground-Based Stage IV BAO Experiment

    Energy Technology Data Exchange (ETDEWEB)

    Schlegel, David; Bebek, Chris; Heetderks, Henry; Ho, Shirley; Lampton, Michael; Levi, Michael; Mostek, Nick; Padmanabhan, Nikhil; Perlmutter, Saul; Roe, Natalie; Sholl, Michael; Smoot, George; White, Martin; Dey, Arjun; Abraham, Tony; Jannuzi, Buell; Joyce, Dick; Liang, Ming; Merrill, Mike; Olsen, Knut; Salim, Samir

    2009-04-01

    The BigBOSS experiment is a proposed DOE-NSF Stage IV ground-based dark energy experiment to study baryon acoustic oscillations (BAO) and the growth of structure with an all-sky galaxy redshift survey. The project is designed to unlock the mystery of dark energy using existing ground-based facilities operated by NOAO. A new 4000-fiber R=5000 spectrograph covering a 3-degree diameter field will measure BAO and redshift space distortions in the distribution of galaxies and hydrogen gas spanning redshifts from 0.2< z< 3.5. The Dark Energy Task Force figure of merit (DETF FoM) for this experiment is expected to be equal to that of a JDEM mission for BAO with the lower risk and cost typical of a ground-based experiment.

  17. Comparing Dawn, Hubble Space Telescope, and Ground-Based Interpretations of (4) Vesta

    CERN Document Server

    Reddy, Vishnu; Corre, Lucille Le; Scully, Jennifer E C; Gaskell, Robert; Russell, Christopher T; Park, Ryan S; Nathues, Andreas; Raymond, Carol; Gaffey, Michael J; Sierks, Holger; Becker, Kris J; McFadden, Lucy A

    2013-01-01

    Observations of asteroid 4 Vesta by NASA's Dawn spacecraft are interesting because its surface has the largest range of albedo, color and composition of any other asteroid visited by spacecraft to date. These hemispherical and rotational variations in surface brightness and composition have been attributed to impact processes since Vesta's formation. Prior to Dawn's arrival at Vesta, its surface properties were the focus of intense telescopic investigations for nearly a hundred years. Ground-based photometric and spectroscopic observations first revealed these variations followed later by those using Hubble Space Telescope. Here we compare interpretations of Vesta's rotation period, pole, albedo, topographic, color, and compositional properties from ground-based telescopes and HST with those from Dawn. Rotational spectral variations observed from ground-based studies are also consistent with those observed by Dawn. While the interpretation of some of these features was tenuous from past data, the interpretati...

  18. High-precision ground-based photometry of exoplanets

    Directory of Open Access Journals (Sweden)

    de Mooij Ernst J.W.

    2013-04-01

    Full Text Available High-precision photometry of transiting exoplanet systems has contributed significantly to our understanding of the properties of their atmospheres. The best targets are the bright exoplanet systems, for which the high number of photons allow very high signal-to-noise ratios. Most of the current instruments are not optimised for these high-precision measurements, either they have a large read-out overhead to reduce the readnoise and/or their field-of-view is limited, preventing simultaneous observations of both the target and a reference star. Recently we have proposed a new wide-field imager for the Observatoir de Mont-Megantic optimised for these bright systems (PI: Jayawardhana. The instruments has a dual beam design and a field-of-view of 17' by 17'. The cameras have a read-out time of 2 seconds, significantly reducing read-out overheads. Over the past years we have obtained significant experience with how to reach the high precision required for the characterisation of exoplanet atmospheres. Based on our experience we provide the following advice: Get the best calibrations possible. In the case of bad weather, characterise the instrument (e.g. non-linearity, dome flats, bias level, this is vital for better understanding of the science data. Observe the target for as long as possible, the out-of-transit baseline is as important as the transit/eclipse itself. A short baseline can lead to improperly corrected systematic and mis-estimation of the red-noise. Keep everything (e.g. position on detector, exposure time as stable as possible. Take care that the defocus is not too strong. For a large defocus, the contribution of the total flux from the sky-background in the aperture could well exceed that of the target, resulting in very strict requirements on the precision at which the background is measured.

  19. Evaluation of Real-Time Ground-Based GPS Meteorology

    Science.gov (United States)

    Fang, P.; Bock, Y.; Gutman, S.

    2003-04-01

    We demonstrate and evaluate a system to estimate zenith tropospheric delays in real time (5-10 minute latency) based on the technique of instantaneous GPS positioning as described by Bock et al. [2000] using data from the Orange County Real Time GPS Network. OCRTN is an upgrade of a sub-network of SCIGN sites in southern California to low latency (1-2 sec), high-rate (1 Hz) data streaming. Currently, ten sites are streaming data (Ashtech binary MBEN format) by means of dedicated, point-to-point radio modems to a network hub that translates the asynchronous serial data to TCP/IP and onto a PC workstation residing on a local area network. Software residing on the PC allows multiple clients to access the raw data simultaneously though TCP/IP. One of the clients is a Geodetics RTD server that receives and archives (1) the raw 1 Hz network data, (2) estimates of instantaneous positions and zenith tropospheric delays, and (3) RINEX data to decimated to 30 seconds. The network is composed of ten sites. The distribution of nine of the sites approximates a right triangle with two 60 km legs, and a tenth site on Catalina Island a distance of about 50 km (over water) from the hypotenuse of the triangle. Relative zenith delays are estimated every second with a latency less than a second. Median values are computed at a user-specified interval (e.g., 10 minutes) with outliers greater than 4 times the interquartile range rejected. We describe the results with those generated by our operational system using the GAMIT software, with a latency of 30-60 minutes. Earlier results (from a similar network) comparing 30-minute median RTD values to GAMIT 30-minute estimates indicate that the two solutions differ by about 1 cm. We also describe our approach to determining absolute zenith delays. If an Internet connection is available we will present a real-time demonstration. [Bock, Y., R. Nikolaidis, P. J. de Jonge, and M. Bevis, Instantaneous resolution of crustal motion at medium

  20. OGLE-2015-BLG-0196: Ground-based Gravitational Microlens Parallax Confirmed By Space-Based Observation

    CERN Document Server

    Han, C; Gould, A; Zhu, Wei; Szymański, M K; Soszyński, I; Skowron, J; Mróz, P; Poleski, R; Pietrukowicz, P; Kozłowski, S; Ulaczyk, K; Pawlak, M; Yee, J C; Beichman, C; Novati, S Calchi; Carey, S; Bryden, C; Fausnaugh, M; Gaudi, B S; Henderson, Calen B; Shvartzvald, Y; Wibking, B

    2016-01-01

    In this paper, we present the analysis of the binary gravitational microlensing event OGLE-2015-BLG-0196. The event lasted for almost a year and the light curve exhibited significant deviations from the lensing model based on the rectilinear lens-source relative motion, enabling us to measure the microlens parallax. The ground-based microlens parallax is confirmed by the data obtained from space-based microlens observations using the {\\it Spitzer} telescope. By additionally measuring the angular Einstein radius from the analysis of the resolved caustic crossing, the physical parameters of the lens are determined up to the two-fold degeneracy: $u_00$ solutions caused by the well-known "ecliptic" degeneracy. It is found that the binary lens is composed of two M dwarf stars with similar masses $M_1=0.38\\pm 0.04\\ M_\\odot$ ($0.50\\pm 0.05\\ M_\\odot)$ and $M_2=0.38\\pm 0.04\\ M_\\odot$ ($0.55\\pm 0.06\\ M_\\odot$) and the distance to the lens is $D_{\\rm L}=2.77\\pm 0.23$ kpc ($3.30\\pm 0.29$ kpc). Here the physical parameter...

  1. First ground-based FTIR-observations of methane in the tropics

    Directory of Open Access Journals (Sweden)

    A. K. Petersen

    2010-02-01

    Full Text Available Total column concentrations and volume mixing ratio profiles of methane have been retrieved from ground-based solar absorption FTIR spectra in the near-infrared recorded in Paramaribo (Suriname. The methane FTIR observations are compared with TM5 model simulations and satellite observations from SCIAMACHY, and represent the first validation of SCIAMACHY retrievals in the tropics using ground-based remote sensing techniques. Apart from local biomass burning features, our methane FTIR observations agree well with the SCIAMACHY retrievals and TM5 model simulations.

  2. Extended lateral heating of the nighttime ionosphere by ground-based VLF transmitters

    OpenAIRE

    İnan, Umran Savaş; Graf, K. L.; Spasojevic, M.; Marshall, R. A.; Lehtinen, N. G.; Foust, F. R.

    2013-01-01

    JOURNAL OF GEOPHYSICAL RESEARCH: SPACE PHYSICS, VOL. 118, 7783–7797, doi:10.1002/2013JA019337, 2013 Extended lateral heating of the nighttime ionosphere by ground-based VLF transmitters K. L. Graf,1 M. Spasojevic,1 R. A. Marshall,2 N. G. Lehtinen,1 F. R. Foust,1 and U. S. Inan1,3 Received 16 August 2013; revised 9 October 2013; accepted 11 November 2013; published 3 December 2013. [1] The effects of ground-based very low frequency (VLF) transmitters on the lower ionospher...

  3. A transit timing analysis with combined ground- and space-based photometry

    Directory of Open Access Journals (Sweden)

    Raetz St.

    2015-01-01

    The CoRoT satellite looks back on six years of high precision photometry of a very high number of stars. Thousands of transiting events are detected from which 27 were confirmed to be transiting planets so far. In my research I search and analyze TTVs in the CoRoT sample and combine the unprecedented precision of the light curves with ground-based follow-up photometry. Because CoRoT can observe transiting planets only for a maximum duration of 150 days the ground-based follow-up can help to refine the ephemeris. Here we present first examples.

  4. Status of advanced ground-based laser interferometers for gravitational-wave detection

    CERN Document Server

    Dooley, Katherine L; Dwyer, Sheila; Puppo, Paola

    2014-01-01

    Ground-based laser interferometers for gravitational-wave (GW) detection were first constructed starting 20 years ago and as of 2010 collection of several years' worth of science data at initial design sensitivities was completed. Upgrades to the initial detectors together with construction of brand new detectors are ongoing and feature advanced technologies to improve the sensitivity to GWs. This conference proceeding provides an overview of the common design features of ground-based laser interferometric GW detectors and establishes the context for the status updates of each of the four gravitational-wave detectors around the world: Advanced LIGO, Advanced Virgo, GEO600 and KAGRA.

  5. Asteroseismology of solar-type stars with Kepler: III. Ground-based data

    DEFF Research Database (Denmark)

    Karoff, Christoffer; Molenda-Żakowicz , J.

    2010-01-01

    We report on the ground-based follow-up program of spectroscopic and photometric observations of solar-like asteroseismic targets for the Kepler space mission. These stars constitute a large group of more than a thousand objects which are the subject of an intensive study by the Kepler Asteroseis......We report on the ground-based follow-up program of spectroscopic and photometric observations of solar-like asteroseismic targets for the Kepler space mission. These stars constitute a large group of more than a thousand objects which are the subject of an intensive study by the Kepler...

  6. Estimation of solar irradiance using ground-based whole sky imagers

    CERN Document Server

    Dev, Soumyabrata; Lee, Yee Hui; Winkler, Stefan

    2016-01-01

    Ground-based whole sky imagers (WSIs) can provide localized images of the sky of high temporal and spatial resolution, which permits fine-grained cloud observation. In this paper, we show how images taken by WSIs can be used to estimate solar radiation. Sky cameras are useful here because they provide additional information about cloud movement and coverage, which are otherwise not available from weather station data. Our setup includes ground-based weather stations at the same location as the imagers. We use their measurements to validate our methods.

  7. Intuitive Terrain Reconstruction Using Height Observation-Based Ground Segmentation and 3D Object Boundary Estimation

    Directory of Open Access Journals (Sweden)

    Sungdae Sim

    2012-12-01

    Full Text Available Mobile robot operators must make rapid decisions based on information about the robot’s surrounding environment. This means that terrain modeling and photorealistic visualization are required for the remote operation of mobile robots. We have produced a voxel map and textured mesh from the 2D and 3D datasets collected by a robot’s array of sensors, but some upper parts of objects are beyond the sensors’ measurements and these parts are missing in the terrain reconstruction result. This result is an incomplete terrain model. To solve this problem, we present a new ground segmentation method to detect non-ground data in the reconstructed voxel map. Our method uses height histograms to estimate the ground height range, and a Gibbs-Markov random field model to refine the segmentation results. To reconstruct a complete terrain model of the 3D environment, we develop a 3D boundary estimation method for non-ground objects. We apply a boundary detection technique to the 2D image, before estimating and refining the actual height values of the non-ground vertices in the reconstructed textured mesh. Our proposed methods were tested in an outdoor environment in which trees and buildings were not completely sensed. Our results show that the time required for ground segmentation is faster than that for data sensing, which is necessary for a real-time approach. In addition, those parts of objects that were not sensed are accurately recovered to retrieve their real-world appearances.

  8. Intuitive terrain reconstruction using height observation-based ground segmentation and 3D object boundary estimation.

    Science.gov (United States)

    Song, Wei; Cho, Kyungeun; Um, Kyhyun; Won, Chee Sun; Sim, Sungdae

    2012-12-12

    Mobile robot operators must make rapid decisions based on information about the robot's surrounding environment. This means that terrain modeling and photorealistic visualization are required for the remote operation of mobile robots. We have produced a voxel map and textured mesh from the 2D and 3D datasets collected by a robot's array of sensors, but some upper parts of objects are beyond the sensors' measurements and these parts are missing in the terrain reconstruction result. This result is an incomplete terrain model. To solve this problem, we present a new ground segmentation method to detect non-ground data in the reconstructed voxel map. Our method uses height histograms to estimate the ground height range, and a Gibbs-Markov random field model to refine the segmentation results. To reconstruct a complete terrain model of the 3D environment, we develop a 3D boundary estimation method for non-ground objects. We apply a boundary detection technique to the 2D image, before estimating and refining the actual height values of the non-ground vertices in the reconstructed textured mesh. Our proposed methods were tested in an outdoor environment in which trees and buildings were not completely sensed. Our results show that the time required for ground segmentation is faster than that for data sensing, which is necessary for a real-time approach. In addition, those parts of objects that were not sensed are accurately recovered to retrieve their real-world appearances.

  9. Precision simulation of ground-based lensing data using observations from space

    CERN Document Server

    Mandelbaum, Rachel; Leauthaud, Alexie; Massey, Richard J; Rhodes, Jason

    2011-01-01

    Current and upcoming wide-field, ground-based, broad-band imaging surveys promise to address a wide range of outstanding problems in galaxy formation and cosmology. Several such uses of ground-based data, especially weak gravitational lensing, require highly precise measurements of galaxy image statistics with careful correction for the effects of the point-spread function (PSF). In this paper, we introduce the SHERA (SHEar Reconvolution Analysis) software to simulate ground-based imaging data with realistic galaxy morphologies and observing conditions, starting from space-based data (from COSMOS, the Cosmological Evolution Survey) and accounting for the effects of the space-based PSF. This code simulates ground-based data, optionally with a weak lensing shear applied, in a model-independent way using a general Fourier space formalism. The utility of this pipeline is that it allows for a precise, realistic assessment of systematic errors due to the method of data processing, for example in extracting weak len...

  10. Finding common ground in team-based qualitative research using the convergent interviewing method.

    Science.gov (United States)

    Driedger, S Michelle; Gallois, Cindy; Sanders, Carrie B; Santesso, Nancy

    2006-10-01

    Research councils, agencies, and researchers recognize the benefits of team-based health research. However, researchers involved in large-scale team-based research projects face multiple challenges as they seek to identify epistemological and ontological common ground. Typically, these challenges occur between quantitative and qualitative researchers but can occur between qualitative researchers, particularly when the project involves multiple disciplinary perspectives. The authors use the convergent interviewing technique in their multidisciplinary research project to overcome these challenges. This technique assists them in developing common epistemological and ontological ground while enabling swift and detailed data collection and analysis. Although convergent interviewing is a relatively new method described primarily in marketing research, it compares and contrasts well with grounded theory and other techniques. The authors argue that this process provides a rigorous method to structure and refine research projects and requires researchers to identify and be accountable for developing a common epistemological and ontological position.

  11. Ground-Based VIS/NIR Reflectance Spectra of 25143 Itokawa: What Hayabusa will See and How Ground-Based Data can Augment Analyses

    Science.gov (United States)

    Vilas, Faith; Abell, P. A.; Jarvis, K. S.

    2004-01-01

    Planning for the arrival of the Hayabusa spacecraft at asteroid 25143 Itokawa includes consideration of the expected spectral information to be obtained using the AMICA and NIRS instruments. The rotationally-resolved spatial coverage the asteroid we have obtained with ground-based telescopic spectrophotometry in the visible and near-infrared can be utilized here to address expected spacecraft data. We use spectrophotometry to simulate the types of data that Hayabusa will receive with the NIRS and AMICA instruments, and will demonstrate them here. The NIRS will cover a wavelength range from 0.85 m, and have a dispersion per element of 250 Angstroms. Thus, we are limited in coverage of the 1.0 micrometer and 2.0 micrometer mafic silicate absorption features. The ground-based reflectance spectra of Itokawa show a large component of olivine in its surface material, and the 2.0 micrometer feature is shallow. Determining the olivine to pyroxene abundance ratio is critically dependent on the attributes of the 1.0- and 2.0 micrometer features. With a cut-off near 2,1 micrometer the longer edge of the 2.0- feature will not be obtained by NIRS. Reflectance spectra obtained using ground-based telescopes can be used to determine the regional composition around space-based spectral observations, and possibly augment the longer wavelength spectral attributes. Similarly, the shorter wavelength end of the 1.0 micrometer absorption feature will be partially lost to the NIRS. The AMICA filters mimic the ECAS filters, and have wavelength coverage overlapping with the NIRS spectral range. We demonstrate how merging photometry from AMICA will extend the spectral coverage of the NIRS. Lessons learned from earlier spacecraft to asteroids should be considered.

  12. Simulation of the imaging quality of ground-based telescopes affected by atmospheric disturbances

    Science.gov (United States)

    Ren, Yubin; Kou, Songfeng; Gu, Bozhong

    2014-08-01

    Ground-based telescope imaging model is developed in this paper, the relationship between the atmospheric disturbances and the ground-based telescope image quality is studied. Simulation of the wave-front distortions caused by atmospheric turbulences has long been an important method in the study of the propagation of light through the atmosphere. The phase of the starlight wave-front is changed over time, but in an appropriate short exposure time, the atmospheric disturbances can be considered as "frozen". In accordance with Kolmogorov turbulence theory, simulating atmospheric disturbances of image model based on the phase screen distorted by atmospheric turbulences is achieved by the fast Fourier transform (FFT). Geiger mode avalanche photodiode array (APD arrays) model is used for atmospheric wave-front detection, the image is achieved by inversion method of photon counting after the target starlight goes through phase screens and ground-based telescopes. Ground-based telescope imaging model is established in this paper can accurately achieve the relationship between the quality of telescope imaging and monolayer or multilayer atmosphere disturbances, and it is great significance for the wave-front detection and optical correction in a Multi-conjugate Adaptive Optics system (MCAO).

  13. Hanford ground-water data base management guide and user's manual. [CIRMIS

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, P.J.; Argo, R.S.; Bradymire, S.L.; Newbill, C.A.

    1985-05-01

    This management guide and user's manual is a working document for the computerized Hanford Ground-water Data Base maintained by the Geosciences Research and Engineering Department at Pacific Northwest Laboratory for the Hanford Ground-Water Surveillance Program. The program is managed by the Occupational and Environmental Protection Department for the US Department of Energy. The data base is maintained to provide rapid access to data that are rountinely collected from ground-water monitoring wells at the Hanford site. The data include water levels, sample analyses, geologic descriptions and well construction information of over 3000 existing or destroyed wells. These data are used to monitor water quality and for the evaluation of ground-water flow and pollutant transport problems. The management guide gives instructions for maintenance of the data base on the Digital Equipment Corporation PDP 11/70 Computer using the CIRMIS (Comprehensive Information Retrieval and Model Input Sequence) data base management software developed at Pacific Northwest Laboratory. Maintenance activities include inserting, modifying and deleting data, making back-up copies of the data base, and generating tables for annual monitoring reports. The user's guide includes instructions for running programs to retrieve the data in the form of listings of graphical plots. 3 refs.

  14. A Robust and Efficient Homography Based Approach for Ground Plane Detection

    Directory of Open Access Journals (Sweden)

    Sanjeev Sofat

    2012-07-01

    Full Text Available This paper presents a homography based ground planedetection method. The method is developed as a part of stereovision based obstacle detection technique for the visuallyimpaired people. The method assumes the presence of a texturedominant ground plane in the lower portion of the scene, whichis not severe restriction in a real world. SIFT algorithm is usedto extract features in the stereo images. The extracted SIFTfeatures are robustly matched by model fitting using RANSAC.A sample of putative matches lying in the lower portion of theimage is selected. A fitness function is developed to selectmatches from this sample, which are used to estimate groundplane homography hypothesis. The ground plane homographyhypothesis is used to classify the SIFT features as eitherbelonging to ground plane or not. Image segmentation usingmean shift and normalized cut is further used to filter theoutliers and augment the ground plane. Experimental testshave been conducted to test the performance of the proposedapproach. The tests indicate that the proposed approach hasgood classification rate and have operating distance rangefrom 3 feet to 12 feet.

  15. Development of access-based metrics for site location of ground segment in LEO missions

    Directory of Open Access Journals (Sweden)

    Hossein Bonyan Khamseh

    2010-09-01

    Full Text Available The classical metrics of ground segment site location do not take account of the pattern of ground segment access to the satellite. In this paper, based on the pattern of access between the ground segment and the satellite, two metrics for site location of ground segments in Low Earth Orbits (LEO missions were developed. The two developed access-based metrics are total accessibility duration and longest accessibility gap in a given period of time. It is shown that repeatability cycle is the minimum necessary time interval to study the steady behavior of the two proposed metrics. System and subsystem characteristics of the satellite represented by each of the metrics are discussed. Incorporation of the two proposed metrics, along with the classical ones, in the ground segment site location process results in financial saving in satellite development phase and reduces the minimum required level of in-orbit autonomy of the satellite. To show the effectiveness of the proposed metrics, simulation results are included for illustration.

  16. Which future for electromagnetic Astronomy: Ground Based vs Space Borne Large Astrophysical Facilities

    Science.gov (United States)

    Ubertini, Pietro

    2015-08-01

    The combined use of large ground based facilities and large space observatories is playing a key role in the advance of astrophysics by providing access to the entire electromagnetic spectrum, allowing high sensitivity observations from the lower radio wavelength to the higher energy gamma rays.It is nowadays clear that a forward steps in the understanding of the Universe evolution and large scale structure formation is essential and only possible with the combined use of multiwavelength imaging and spectral high resolution instruments.The increasing size, complexity and cost of large ground and space observatories places a growing emphasis on international collaboration. If the present set of astronomical facilities is impressive and complete, with nicely complementary space and ground based telescopes, the scenario becomes worrisome and critical in the next two decades. In fact, only a few ‘Large’ main space missions are planned and there is a need to ensure proper ground facility coverage: the synergy Ground-Space is not escapable in the timeframe 2020-2030.The scope of this talk is to review the current astronomical instrumentation panorama also in view of the recent major national agencies and international bodies programmatic decisions.This Division B meeting give us a unique opportunity to review the current situation and discuss the future perspectives taking advantage of the large audience ensured by the IAU GA.

  17. Ground Control Point - Wireless System Network for UAV-based environmental monitoring applications

    Science.gov (United States)

    Mejia-Aguilar, Abraham

    2016-04-01

    In recent years, Unmanned Aerial Vehicles (UAV) have seen widespread civil applications including usage for survey and monitoring services in areas such as agriculture, construction and civil engineering, private surveillance and reconnaissance services and cultural heritage management. Most aerial monitoring services require the integration of information acquired during the flight (such as imagery) with ground-based information (such as GPS information or others) for improved ground truth validation. For example, to obtain an accurate 3D and Digital Elevation Model based on aerial imagery, it is necessary to include ground-based information of coordinate points, which are normally acquired with surveying methods based on Global Position Systems (GPS). However, GPS surveys are very time consuming and especially for longer time series of monitoring data repeated GPS surveys are necessary. In order to improve speed of data collection and integration, this work presents an autonomous system based on Waspmote technologies build on single nodes interlinked in a Wireless Sensor Network (WSN) star-topology for ground based information collection and later integration with surveying data obtained by UAV. Nodes are designed to be visible from the air, to resist extreme weather conditions with low-power consumption. Besides, nodes are equipped with GPS as well as Inertial Measurement Unit (IMU), accelerometer, temperature and soil moisture sensors and thus provide significant advantages in a broad range of applications for environmental monitoring. For our purpose, the WSN transmits the environmental data with 3G/GPRS to a database on a regular time basis. This project provides a detailed case study and implementation of a Ground Control Point System Network for UAV-based vegetation monitoring of dry mountain grassland in the Matsch valley, Italy.

  18. On reconciling ground-based with spaceborne normalized radar cross section measurements

    DEFF Research Database (Denmark)

    Baumgartner, Francois; Munk, Jens; Jezek, K C

    2002-01-01

    This study examines differences in the normalized radar cross section, derived from ground-based versus spaceborne radar data. A simple homogeneous half-space model, indicates that agreement between the two improves as 1) the distance from the scatterer is increased; and/or 2) the extinction...

  19. Facilitating Grounded Online Interactions in Video-Case-Based Teacher Professional Development

    Science.gov (United States)

    Nemirovsky, Ricardo; Galvis, Alvaro

    2004-01-01

    The use of interactive video cases for teacher professional development is an emergent medium inspired by case study methods used extensively in law, management, and medicine, and by the advent of multimedia technology available to support online discussions. This paper focuses on Web-based "grounded" discussions--in which the participants base…

  20. Ground-based LIDAR: a novel approach to quantify fine-scale fuelbed characteristics

    Science.gov (United States)

    E.L. Loudermilk; J.K. Hiers; J.J. O’Brien; R.J. Mitchell; A. Singhania; J.C. Fernandez; W.P. Cropper; K.C. Slatton

    2009-01-01

    Ground-based LIDAR (also known as laser ranging) is a novel technique that may precisely quantify fuelbed characteristics important in determining fire behavior. We measured fuel properties within a south-eastern US longleaf pine woodland at the individual plant and fuelbed scale. Data were collected using a mobile terrestrial LIDAR unit at sub-cm scale for individual...

  1. Identifying Barriers in Implementing Outcomes-Based Assessment Program Review: A Grounded Theory Analysis

    Science.gov (United States)

    Bresciani, Marilee J.

    2011-01-01

    The purpose of this grounded theory study was to identify the typical barriers encountered by faculty and administrators when implementing outcomes-based assessment program review. An analysis of interviews with faculty and administrators at nine institutions revealed a theory that faculty and administrators' promotion, tenure (if applicable),…

  2. Use of neural networks in ground-based aerosol retrievals from multi-angle spectropolarimetric observations

    NARCIS (Netherlands)

    Di Noia, A.; Hasekamp, O.P.; Harten, G. van; Rietjens, J.H.H.; Smit, J.M.; Snik, F.; Henzing, J.S.; Boer, J. de; Keller, C.U.; Volten, H.

    2015-01-01

    In this paper, the use of a neural network algorithm for the retrieval of the aerosol properties from ground-based spectropolarimetric measurements is discussed. The neural network is able to retrieve the aerosol properties with an accuracy that is almost comparable to that of an iterative retrieval

  3. Retrieval of liquid water cloud properties from ground-based remote sensing observations

    NARCIS (Netherlands)

    Knist, C.L.

    2014-01-01

    Accurate ground-based remotely sensed microphysical and optical properties of liquid water clouds are essential references to validate satellite-observed cloud properties and to improve cloud parameterizations in weather and climate models. This requires the evaluation of algorithms for retrieval of

  4. Ground-based remote sensing scheme for monitoring aerosol–cloud interactions (discussion)

    NARCIS (Netherlands)

    Sarna, K.; Russchenberg, H.W.J.

    2015-01-01

    A method for continuous observation of aerosol–cloud interactions with ground-based remote sensing instruments is presented. The main goal of this method is to enable the monitoring of cloud microphysical changes due to the changing aerosol concentration. We use high resolution measurements from lid

  5. Ground-based remote sensing scheme for monitoring aerosol-cloud interactions

    NARCIS (Netherlands)

    Sarna, K.; Russchenberg, H.W.J.

    2016-01-01

    A new method for continuous observation of aerosol–cloud interactions with ground-based remote sensing instruments is presented. The main goal of this method is to enable the monitoring of the change of the cloud droplet size due to the change in the aerosol concentration. We use high-resolution mea

  6. Asteroseismology of solar-type stars with Kepler: III. Ground-based data

    DEFF Research Database (Denmark)

    Karoff, Christoffer; Molenda-Żakowicz , J.

    2010-01-01

    We report on the ground-based follow-up program of spectroscopic and photometric observations of solar-like asteroseismic targets for the Kepler space mission. These stars constitute a large group of more than a thousand objects which are the subject of an intensive study by the Kepler Asteroseis...

  7. A Fast Method for Embattling Optimization of Ground-Based Radar Surveillance Network

    Science.gov (United States)

    Jiang, H.; Cheng, H.; Zhang, Y.; Liu, J.

    A growing number of space activities have created an orbital debris environment that poses increasing impact risks to existing space systems and human space flight. For the safety of in-orbit spacecraft, a lot of observation facilities are needed to catalog space objects, especially in low earth orbit. Surveillance of Low earth orbit objects are mainly rely on ground-based radar, due to the ability limitation of exist radar facilities, a large number of ground-based radar need to build in the next few years in order to meet the current space surveillance demands. How to optimize the embattling of ground-based radar surveillance network is a problem to need to be solved. The traditional method for embattling optimization of ground-based radar surveillance network is mainly through to the detection simulation of all possible stations with cataloged data, and makes a comprehensive comparative analysis of various simulation results with the combinational method, and then selects an optimal result as station layout scheme. This method is time consuming for single simulation and high computational complexity for the combinational analysis, when the number of stations increases, the complexity of optimization problem will be increased exponentially, and cannot be solved with traditional method. There is no better way to solve this problem till now. In this paper, target detection procedure was simplified. Firstly, the space coverage of ground-based radar was simplified, a space coverage projection model of radar facilities in different orbit altitudes was built; then a simplified objects cross the radar coverage model was established according to the characteristics of space objects orbit motion; after two steps simplification, the computational complexity of the target detection was greatly simplified, and simulation results shown the correctness of the simplified results. In addition, the detection areas of ground-based radar network can be easily computed with the

  8. An Improved Algorithm of Grounding Grids Corrosion Diagnosis Based on Total Least Square Method

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ying-jiao; NIU Tao; WANG Sen

    2011-01-01

    A new model considering corrosion property for grounding grids diagnosis is proposed, which provides reference solutions of ambiguous branches. The constraint total least square method based on singular value decomposition is adopted to improve the effectiveness of grounding grids' diagnosis algorithm. The improvement can weaken the influence of the model's error, which results from the differences between design paper and actual grid. Its influence on touch and step voltages caused by the interior resistance of conductors is taken into account. Simulation results show the validity of this approach.

  9. A Dynamic Programming-Based Heuristic for the Shift Design Problem in Airport Ground Handling

    DEFF Research Database (Denmark)

    Clausen, Tommy

    We consider the heterogeneous shift design problem for a workforce with multiple skills, where work shifts are created to cover a given demand as well as possible while minimizing cost and satisfying a flexible set of constraints. We focus mainly on applications within airport ground handling where...... the demand can be highly irregular and specified on time intervals as short as five minutes. Ground handling operations are subject to a high degree of cooperation and specialization that require workers with different qualifications to be planned together. Different labor regulations or organizational rules...... can apply to different ground handling operations, so the rules and restrictions can be numerous and vary significantly. This is modeled using flexible volume constraints that limit the creation of certain shifts. We present a fast heuristic for the heterogeneous shift design problem based on dynamic...

  10. (21) Lutetia spectrophotometry from Rosetta-OSIRIS images and comparison to ground-based observations

    Science.gov (United States)

    Magrin, S.; La Forgia, F.; Pajola, M.; Lazzarin, M.; Massironi, M.; Ferri, F.; da Deppo, V.; Barbieri, C.; Sierks, H.; Osiris Team

    2012-06-01

    Here we present some preliminary results on surface variegation found on (21) Lutetia from ROSETTA-OSIRIS images acquired on 2010-07-10. The spectrophotometry obtained by means of the two cameras NAC and WAC (Narrow and Wide Angle Cameras) is consistent with ground based observations, and does not show surface diversity above the data error bars. The blue and UV images (shortward 500 nm) may, however, indicate a variegation of the optical properties of the asteroid surface on the Baetica region (Sierks et al., 2011). We also speculate on the contribution due to different illumination and to different ground properties (composition or, more probably, grain size diversity). In particular a correlation with geologic units independently defined by Massironi et al. (2012) is evident, suggesting that the variegation of the ground optical properties is likely to be real.

  11. Protection Measures for Buildings Based on Coordinating Action Theory of Ground, Foundation and Structure

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Based on the theory of coordinating action of building ground, foundation and structure, this paper presents a modified method for calculating additional stresses on buildings in mining areas by considering the joint effect of curvature deformation and horizontal deformation on buildings. It points out that for buildings over the coal pillar, it is advisable to soften the intermediate ground of buildings when they are affected by mining. For buildings over the goaf, it is preferable to soften the ground at both ends of buildings. In order to enhance the ability of a building to resist tensile deformation, the key measure is to reinforce the bottom foundation of the building. In addition, the concept of "angle of break of building" is proposed. It is because of this angle that the protecting coal pillar is left, which is a better solution than prevailing solutions The findings provide a more scientific basis for mining under buildings.

  12. Ground truth delineation for medical image segmentation based on Local Consistency and Distribution Map analysis.

    Science.gov (United States)

    Cheng, Irene; Sun, Xinyao; Alsufyani, Noura; Xiong, Zhihui; Major, Paul; Basu, Anup

    2015-01-01

    Computer-aided detection (CAD) systems are being increasingly deployed for medical applications in recent years with the goal to speed up tedious tasks and improve precision. Among others, segmentation is an important component in CAD systems as a preprocessing step to help recognize patterns in medical images. In order to assess the accuracy of a CAD segmentation algorithm, comparison with ground truth data is necessary. To-date, ground truth delineation relies mainly on contours that are either manually defined by clinical experts or automatically generated by software. In this paper, we propose a systematic ground truth delineation method based on a Local Consistency Set Analysis approach, which can be used to establish an accurate ground truth representation, or if ground truth is available, to assess the accuracy of a CAD generated segmentation algorithm. We validate our computational model using medical data. Experimental results demonstrate the robustness of our approach. In contrast to current methods, our model also provides consistency information at distributed boundary pixel level, and thus is invariant to global compensation error.

  13. Seeing statistics at the upgraded 3.8m UK infrared telescope (UKIRT)

    CERN Document Server

    Seigar, M S; Rees, N P; Hawarden, T G; Currie, M; Chuter, T C; Seigar, Marc S.; Adamson, Andy J.; Rees, Nicholas P.; Hawarden, Timothy G.; Currie, Malcolm; Chuter, Timothy C.

    2002-01-01

    From 1991 until 1997, the 3.8m UK Infrared Telescope (UKIRT) underwent a programme of upgrades aimed at improving its intrinsic optical performance. This resulted in images with a FWHM of 0."17 at 2.2 um in September 1998. To understand and maintain the improvements to the delivered image quality since the completion of the upgrades programme, we have regularly monitored the overall atmospheric seeing, as measured by radial displacements of subaperture images (i.e. seeing-generated focus fluctuations), and the delivered image diameters. The latter have been measured and recorded automatically since the beginning of 2001 whenever the facility imager UFTI (UKIRT Fast Track Imager) has been in use. In this paper we report the results of these measurements. We investigate the relation between the delivered image diameter and the RMS atmospheric seeing (as measured by focus fluctuations, mentioned above). We find that the best seeing occurs in the second half of the night, generally after 2am HST and that the best...

  14. Development of silver coating options for the Gemini 8-m telescopes project

    Science.gov (United States)

    Jacobson, Michael R.; Kneale, Ruth C.; Gillett, Fred C.; Raybould, Keith; Filhaber, John M.; Carniglia, Charles K.; Laird, Ronald; Kitchens, Dennis; Shimshock, Ric P.; Booth, Donald C.

    1998-08-01

    Acting as a prime contractor to the Gemini Project, the Optical Data Associates (ODA), with its major subcontractors, BOC Coating Technologies (BOCCT) and Deposition Sciences, Inc. (DSI), developed options for depositing protected silver coatings on the 8-M primary mirrors. The project began with a study that identified sputtering as the preferred deposition technique, defined a set of candidate adhesor and protective coatings for the silver layer, and simulated stack performance. The next phase involved pilot magnetron sputtering studies by BOCCT and DSI of designs involving silicon nitride and hafnia, respectively. ODA also developed mid-IR reflectance standards at (lambda) equals 10.6 micrometers to control the silver coating measurements in the critical 8 - 12 micrometers atmospheric window. The study results were successful, with both BOCCT and DSI producing Ag coatings with R equals 0.9920 +/- 0.0001 and protected Ag coatings with R equals 0.9910 +/- 0.0001. The Gemini Project coating plants are designed to sputter bare and protected Al and Ag coatings.

  15. Particle production during inflation and gravitational waves detectable by ground-based interferometers

    OpenAIRE

    Cook, Jessica L.; Sorbo, Lorenzo

    2011-01-01

    Inflation typically predicts a quasi scale-invariant spectrum of gravitational waves. In models of slow-roll inflation, the amplitude of such a background is too small to allow direct detection without a dedicated space-based experiment such as the proposed BBO or DECIGO. In this paper we note that particle production during inflation can generate a feature in the spectrum of primordial gravitational waves. We discuss the possibility that such a feature might be detected by ground-based laser...

  16. Comparison of NO2 vertical profiles from satellite and ground based measurements over Antarctica

    OpenAIRE

    Kulkarni, Pavan; Bortoli, Daniele; Costa, Maria João; Silva, Ana Maria; Ravegnani, Fabrizio; Giovanelli, Giorgio

    2011-01-01

    The Intercomparison of nitrogen dioxide (NO2) vertical profiles, derived from the satellite based HALogen Occultation Experiment (HALOE) measurements and from the ground based UV-VIS spectrometer GASCOD (Gas Analyzer Spectrometer Correlating Optical Differences) observations at the Mario Zucchelli Station (MZS), in Antarctica, are done for the first time. It is shown here that both datasets are in good agreement showing the same features in terms of magnitude, profile structure, a...

  17. Shear wave velocity-based evaluation and design of stone column improved ground for liquefaction mitigation

    Institute of Scientific and Technical Information of China (English)

    Zhou Yanguo; Sun Zhengbo; Chen Jie; Chen Yunmin; Chen Renpeng

    2017-01-01

    The evaluation and design of stone column improvement ground for liquefaction mitigation is a challenging issue for the state of practice.In this paper,a shear wave velocity-based approach is proposed based on the well-defined correlations of liquefaction resistance (CRR)-shear wave velocity (Vs)-void ratio (e) of sandy soils,and the values of parameters in this approach are recommended for preliminary design purpose when site specific values are not available.The detailed procedures of pre-and post-improvement liquefaction evaluations and stone column design are given.According to this approach,the required level of ground improvement will be met once the target Vs of soil is raised high enough (i.e.,no less than the critical velocity) to resist the given earthquake loading according to the CRR-Vs relationship,and then this requirement is transferred to the control of target void ratio (i.e.,the critical e) according to the Vs-e relationship.As this approach relies on the densification of the surrounding soil instead of the whole improved ground and is conservative by nature,specific considerations of the densification mechanism and effect are given,and the effects of drainage and reinforcement of stone columns are also discussed.A case study of a thermal power plant in Indonesia is introduced,where the effectiveness of stone column improved ground was evaluated by the proposed Vs-based method and compared with the SPT-based evaluation.This improved ground performed well and experienced no liquefaction during subsequent strong earthquakes.

  18. Shear wave velocity-based evaluation and design of stone column improved ground for liquefaction mitigation

    Science.gov (United States)

    Zhou, Yanguo; Sun, Zhengbo; Chen, Jie; Chen, Yunmin; Chen, Renpeng

    2017-04-01

    The evaluation and design of stone column improvement ground for liquefaction mitigation is a challenging issue for the state of practice. In this paper, a shear wave velocity-based approach is proposed based on the well-defined correlations of liquefaction resistance (CRR)-shear wave velocity ( V s)-void ratio ( e) of sandy soils, and the values of parameters in this approach are recommended for preliminary design purpose when site specific values are not available. The detailed procedures of pre- and post-improvement liquefaction evaluations and stone column design are given. According to this approach, the required level of ground improvement will be met once the target V s of soil is raised high enough (i.e., no less than the critical velocity) to resist the given earthquake loading according to the CRR- V s relationship, and then this requirement is transferred to the control of target void ratio (i.e., the critical e) according to the V s- e relationship. As this approach relies on the densification of the surrounding soil instead of the whole improved ground and is conservative by nature, specific considerations of the densification mechanism and effect are given, and the effects of drainage and reinforcement of stone columns are also discussed. A case study of a thermal power plant in Indonesia is introduced, where the effectiveness of stone column improved ground was evaluated by the proposed V s-based method and compared with the SPT-based evaluation. This improved ground performed well and experienced no liquefaction during subsequent strong earthquakes.

  19. Key Ground-Based and Space-Based Assets to Disentangle Magnetic Field Sources in the Earth's Environment

    Science.gov (United States)

    Chulliat, A.; Matzka, J.; Masson, A.; Milan, S. E.

    2016-10-01

    The magnetic field measured on the ground or in space is the addition of several sources: from flows within the Earth's core to electric currents in distant regions of the magnetosphere. Properly separating and characterizing these sources requires appropriate observations, both ground-based and space-based. In the present paper, we review the existing observational infrastructure, from magnetic observatories and magnetometer arrays on the ground to satellites in low-Earth (Swarm) and highly elliptical (Cluster) orbits. We also review the capability of SuperDARN to provide polar ionospheric convection patterns supporting magnetic observations. The past two decades have been marked by exciting new developments in all observation types. We review these developments, focusing on how they complement each other and how they have led or could lead in the near future to improved separation and modeling of the geomagnetic sources.

  20. Monitoring greenhouse gas emissions in Australian landscapes: Comparing ground based mobile surveying data to GOSAT observations

    Science.gov (United States)

    Bashir, S.; Iverach, C.; Kelly, B. F. J.

    2016-12-01

    Climate change is threatening the health and stability of the natural world and human society. Such concerns were emphasized at COP21 conference in Paris 2015 which highlighted the global need to improve our knowledge of sources of greenhouse gas and to develop methods to mitigate the effects of their emissions. Ongoing spatial and temporal measurements of greenhouse gases at both point and regional scales is important for clarification of climate change mechanisms and accounting. The Greenhouse gas Observing SATellite (GOSAT) is designed to monitor the global distribution of carbon dioxide (CO2) and methane (CH4) from orbit. As existing ground monitoring stations are limited and still unevenly distributed, satellite observations provide important frequent, spatially extensive, but low resolution observations. Recent developments in portable laser based greenhouse gas measurement systems have enabled the rapid measurement of greenhouse gases in ppb at the ground surface. This study was conducted to map major sources of CO2 and CH4 in the eastern states of Australia at the landscape scale and to compare the results to GOSAT observations. During April 2016 we conducted a regional CH4 and CO2 mobile survey, using an LGR greenhouse gas analyzer. Measurements were made along a 4000 KM circuit through major cities, country towns, dry sclerophyll forests, coastal wetlands, coal mining regions, coal seam gas developments, dryland farming and irrigated agricultural landscapes. The ground-based survey data were then compared with the data (L2) from GOSAT. Ground-based mobile surveys showed that there are clear statistical differences in the ground level atmospheric concentration of CH4 and CO2 associated with all major changes in land use. These changes extend for kilometers, and cover one or more GOSAT pixels. In the coal mining districts the ground-level atmospheric concentration of CH4 exceeded 2 ppm for over 40 km, yet this was not discernable in the retrieved data (L2

  1. CRRES/Ground-based multi-instrument observations of an interval of substorm activity

    Directory of Open Access Journals (Sweden)

    T. K. Yeoman

    Full Text Available Observations are presented of data taken during a 3-h interval in which five clear substorm onsets/intensifications took place. During this interval ground-based data from the EISCAT incoherent scatter radar, a digital CCD all sky camera, and an extensive array of magnetometers were recorded. In addition data from the CRRES and DMSP spacecraft, whose footprints passed over Scandinavia very close to most of the ground-based instrumentation, are available. The locations and movements of the substorm current system in latitude and longitude, determined from ground and spacecraft magnetic field data, have been correlated with the locations and propagation of increased particle precipitation in the E-region at EISCAT, increased particle fluxes measured by CRRES and DMSP, with auroral luminosity and with ionospheric convection velocities. The onsets and propagation of the injection of magnetospheric particle populations and auroral luminosity have been compared. CRRES was within or very close to the substorm expansion phase onset sector during the interval. The onset region was observed at low latitudes on the ground, and has been confirmed to map back to within L=7 in the magnetotail. The active region was then observed to propagate tailward and poleward. Delays between the magnetic signature of the substorm field aligned currents and field dipolarisation have been measured. The observations support a near-Earth plasma instability mechanism for substorm expansion phase onset.

  2. Nulling interferometry: performance comparison between space and ground-based sites for exozodiacal disc detection

    CERN Document Server

    Defrère, D; Foresto, V Coudé du; Danchi, W C; Hartog, R den

    2008-01-01

    Characterising the circumstellar dust around nearby main sequence stars is a necessary step in understanding the planetary formation process and is crucial for future life-finding space missions such as ESA's Darwin or NASA's Terrestrial Planet Finder (TPF). Besides paving the technological way to Darwin/TPF, the space-based infrared interferometers Pegase and FKSI (Fourier-Kelvin Stellar Interferometer) will be valuable scientific precursors in that respect. In this paper, we investigate the performance of Pegase and FKSI for exozodiacal disc detection and compare the results with ground-based nulling interferometers. Besides their main scientific goal (characterising hot giant extrasolar planets), Pegase and FKSI are very efficient in assessing within a few minutes the level of circumstellar dust in the habitable zone around nearby main sequence stars. They are capable of detecting exozodiacal discs respectively 5 and 1 time as dense as the solar zodiacal cloud and they outperform any ground-based instrumen...

  3. Validation of Aura OMI by Aircraft and Ground-Based Measurements

    Science.gov (United States)

    McPeters, R. D.; Petropavlovskikh, I.; Kroon, M.

    2006-12-01

    Both aircraft-based and ground-based measurements have been used to validate ozone measurements by the OMI instrument on Aura. Three Aura Validation Experiment (AVE) flights have been conducted, in November 2004 and June 2005 with the NASA WB57, and in January/February 2005 with the NASA DC-8. On these flights, validation of OMI was primarily done using data from the CAFS (CCD Actinic Flux Spectroradiometer) instrument, which is used to measure total column ozone above the aircraft. These measurements are used to differentiate changes in stratospheric ozone from changes in total column ozone. Also, changes in ozone over high clouds measured by OMI were checked in a flight over tropical storm Arlene on a flight on June 11th. Ground-based measurements were made during the SAUNA campaign in Sodankyla, Finland, in March and April 2006. Both total column ozone and the ozone vertical distribution were validated.

  4. REMOTE SENSING OF WATER VAPOR CONTENT USING GROUND-BASED GPS DATA

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Spatial and temporal resolution of water vapor content is useful in improving the accuracy of short-term weather prediction.Dense and continuously tracking regional GPS arrays will play an important role in remote sensing atmospheric water vapor content.In this study,a piecewise linear solution method was proposed to estimate the precipitable water vapor (PWV) content from ground-based GPS observations in Hong Kong.To evaluate the solution accuracy of the water vapor content sensed by GPS,the upper air sounding data (radiosonde) that are collected locally was used to calculate the precipitable water vapor during the same period.One-month results of PWV from both ground-based GPS sensing technique and radiosonde method are in agreement within 1~2 mm.This encouraging result will motivate the GPS meteorology application based on the establishment of a dense GPS array in Hong Kong.

  5. DEM extraction and its accuracy analysis with ground-based SAR interferometry

    Science.gov (United States)

    Dong, J.; Yue, J. P.; Li, L. H.

    2014-03-01

    Two altimetry models extracting DEM (Digital Elevation Model) with the GBSAR (Ground-Based Synthetic Aperture Radar) technology are studied and their accuracies are analyzed in detail. The approximate and improved altimetry models of GBSAR were derived from the spaceborne radar altimetry based on the principles of the GBSAR technology. The error caused by the parallel ray approximation in the approximate model was analyzed quantitatively, and the results show that the errors cannot be ignored for the ground-based radar system. For the improved altimetry model, the elevation error expression can be acquired by simulating and analyzing the error propagation coefficients of baseline length, wavelength, differential phase and range distance in the mathematical model. By analyzing the elevation error with the baseline and range distance, the results show that the improved altimetry model is suitable for high-precision DEM and the accuracy can be improved by adjusting baseline and shortening slant distance.

  6. Empirically Grounded Agent-Based Models of Innovation Diffusion: A Critical Review

    CERN Document Server

    Zhang, Haifeng

    2016-01-01

    Innovation diffusion has been studied extensively in a variety of disciplines, including sociology, economics, marketing, ecology, and computer science. Traditional literature on innovation diffusion has been dominated by models of aggregate behavior and trends. However, the agent-based modeling (ABM) paradigm is gaining popularity as it captures agent heterogeneity and enables fine-grained modeling of interactions mediated by social and geographic networks. While most ABM work on innovation diffusion is theoretical, empirically grounded models are increasingly important, particularly in guiding policy decisions. We present a critical review of empirically grounded agent-based models of innovation diffusion, developing a categorization of this research based on types of agent models as well as applications. By connecting the modeling methodologies in the fields of information and innovation diffusion, we suggest that the maximum likelihood estimation framework widely used in the former is a promising paradigm...

  7. A novel intelligent adaptive control of laser-based ground thermal test

    Directory of Open Access Journals (Sweden)

    Gan Zhengtao

    2016-08-01

    Full Text Available Laser heating technology is a type of potential and attractive space heat flux simulation technology, which is characterized by high heating rate, controlled spatial intensity distribution and rapid response. However, the controlled plant is nonlinear, time-varying and uncertainty when implementing the laser-based heat flux simulation. In this paper, a novel intelligent adaptive controller based on proportion–integration–differentiation (PID type fuzzy logic is proposed to improve the performance of laser-based ground thermal test. The temperature range of thermal cycles is more than 200 K in many instances. In order to improve the adaptability of controller, output scaling factors are real time adjusted while the thermal test is underway. The initial values of scaling factors are optimized using a stochastic hybrid particle swarm optimization (H-PSO algorithm. A validating system has been established in the laboratory. The performance of the proposed controller is evaluated through extensive experiments under different operating conditions (reference and load disturbance. The results show that the proposed adaptive controller performs remarkably better compared to the conventional PID (PID controller and the conventional PID type fuzzy (F-PID controller considering performance indicators of overshoot, settling time and steady state error for laser-based ground thermal test. It is a reliable tool for effective temperature control of laser-based ground thermal test.

  8. A novel intelligent adaptive control of laser-based ground thermal test

    Institute of Scientific and Technical Information of China (English)

    Gan Zhengtao; Yu Gang; Li Shaoxia; He Xiuli; Chen Ru; Zheng Caiyun; Ning Weijian

    2016-01-01

    Laser heating technology is a type of potential and attractive space heat flux simulation technology, which is characterized by high heating rate, controlled spatial intensity distribution and rapid response. However, the controlled plant is nonlinear, time-varying and uncertainty when implementing the laser-based heat flux simulation. In this paper, a novel intelligent adaptive controller based on proportion–integration–differentiation (PID) type fuzzy logic is proposed to improve the performance of laser-based ground thermal test. The temperature range of thermal cycles is more than 200 K in many instances. In order to improve the adaptability of controller, output scaling factors are real time adjusted while the thermal test is underway. The initial values of scaling factors are optimized using a stochastic hybrid particle swarm optimization (H-PSO) algorithm. A validating system has been established in the laboratory. The performance of the pro-posed controller is evaluated through extensive experiments under different operating conditions (reference and load disturbance). The results show that the proposed adaptive controller performs remarkably better compared to the conventional PID (PID) controller and the conventional PID type fuzzy (F-PID) controller considering performance indicators of overshoot, settling time and steady state error for laser-based ground thermal test. It is a reliable tool for effective temperature control of laser-based ground thermal test.

  9. Comparison of Precipitation Observations from a Prototype Space-based Cloud Radar and Ground-based Radars

    Institute of Scientific and Technical Information of China (English)

    LIU Liping; ZHANG Zhiqiang; YU Danru; YANG Hu; ZHAO Chonghui; ZHONG Lingzhi

    2012-01-01

    A prototype space-based cloud radar has been developed and was installed on an airplane to observe a precipitation system over Tianjin,China in July 2010.Ground-based S-band and Ka-band radars were used to examine the observational capability of the prototype. A cross-comparison algorithm between different wavelengths,spatial resolutions and platform radars is presented.The reflectivity biases,correlation coefficients and standard deviations between the radars are analyzed.The equivalent reflectivity bias between the S- and Ka-band radars were simulated with a given raindrop size distribution.The results indicated that reflectivity bias between the S- and Ka-band radars due to scattering properties was less than 5 dB,and for weak precipitation the bias was negligible. The prototype space-based cloud radar was able to measure a reasonable vertical profile of reflectivity,but the reflectivity below an altitude of 1.5 km above ground level was obscured by ground clutter.The measured reflectivity by the prototype space-based cloud radar was approximately 10.9 dB stronger than that by the S-band Doppler radar (SA radar),and 13.7 dB stronger than that by the ground-based cloud radar.The reflectivity measured by the SA radar was 0.4 dB stronger than that by the ground-based cloud radar.This study could provide a method for the quantitative examination of the observation ability for space-based radars.

  10. Progress on the 1.8m solar telescope: the CLST

    Science.gov (United States)

    Rao, Changhui; Gu, Naiting; Zhu, Lei; Li, Cheng; Huang, Jinglong; Cheng, Yuntao; Liu, Yangyi; Yao, Benxi; Wang, Zhiyong; Cao, Xuedong; Zhang, Ming; Zhang, Lanqiang; Liu, Hong; Wan, Yongjian; Xian, Hao; Ma, Wenli

    2016-07-01

    In order to study some special solar activities, such as the emergence, evolution and disappearance progress of the sunspot and magnetic flux, and the key role of magnetic field, a new 1.8-meter size high-resolution solar telescope —the CLST will be built in the Institute of Optics and Electronics(IOE), Chinese Academy of Science(CAS), which locates in Chengdu, China. The CLST has a classic Gregorian configuration, alt-azimuth mount, retractable dome. Besides that, a large mechanical de-rotator will be used to cancel the image rotation, and finally it will cooperate with another kind of mechanical de-rotator to cancel both of the pupil rotation and image rotation. Φ3 arc-minute field of view will help the CLST to observe the whole solar activity region, and if necessary the FOV can be enlarged to Φ 6 arc-minute. A 1.8m primary mirror with honeycomb sandwiches structure made by using ULE material will reduce about 70% of weight. Thermal controlling system will also be equipped for the CLST, which including Heat-Stop, primary mirror, tube truss, mount and the other optics elements. An experimental system for validating thermal controlling of primary mirror and Heat-Stop has been built, and the temperature tracking results will be illustrated in this paper. Currently, we have finished the detailed design of the CLST, and some important components also have been manufactured and finished. In this paper, we describe some important progresses and the latest status of the CLST project during these two years.

  11. Toward High Altitude Airship Ground-Based Boresight Calibration of Hyperspectral Pushbroom Imaging Sensors

    Directory of Open Access Journals (Sweden)

    Aiwu Zhang

    2015-12-01

    Full Text Available The complexity of the single linear hyperspectral pushbroom imaging based on a high altitude airship (HAA without a three-axis stabilized platform is much more than that based on the spaceborne and airborne. Due to the effects of air pressure, temperature and airflow, the large pitch and roll angles tend to appear frequently that create pushbroom images highly characterized with severe geometric distortions. Thus, the in-flight calibration procedure is not appropriate to apply to the single linear pushbroom sensors on HAA having no three-axis stabilized platform. In order to address this problem, a new ground-based boresight calibration method is proposed. Firstly, a coordinate’s transformation model is developed for direct georeferencing (DG of the linear imaging sensor, and then the linear error equation is derived from it by using the Taylor expansion formula. Secondly, the boresight misalignments are worked out by using iterative least squares method with few ground control points (GCPs and ground-based side-scanning experiments. The proposed method is demonstrated by three sets of experiments: (i the stability and reliability of the method is verified through simulation-based experiments; (ii the boresight calibration is performed using ground-based experiments; and (iii the validation is done by applying on the orthorectification of the real hyperspectral pushbroom images from a HAA Earth observation payload system developed by our research team—“LanTianHao”. The test results show that the proposed boresight calibration approach significantly improves the quality of georeferencing by reducing the geometric distortions caused by boresight misalignments to the minimum level.

  12. The comparison between a ground based and a space based probabilistic landslide susceptibility assessment

    Science.gov (United States)

    Reichenbach, P.; Mondini, A.; Guzzetti, F.; Rossi, M.; Ardizzone, F.; Cardinali, M.

    2009-04-01

    , thematic maps obtained processing satellite data can be an effective alternative to maps prepared using more traditional, ground based methods.

  13. Ground Motion Prediction Trends For Eastern North America Based on the Next Generation Attenuation East Ground Motion Database

    Science.gov (United States)

    Cramer, C. H.; Kutliroff, J.; Dangkua, D.

    2010-12-01

    A five-year Next Generation Attenuation (NGA) East project to develop new ground motion prediction equations for stable continental regions (SCRs), including eastern North America (ENA), has begun at the Pacific Earthquake Engineering Research (PEER) Center funded by the Nuclear Regulatory Commission (NRC), the U.S. Geological Survey (USGS), the Electric Power Research Institute (EPRI), and the Department of Energy (DOE). The initial effort focused on database design and collection of appropriate M>4 ENA broadband and accelerograph records to populate the database. Ongoing work has focused on adding records from smaller ENA earthquakes and from other SCRs such as Europe, Australia, and India. Currently, over 6500 horizontal and vertical component records from 60 ENA earthquakes have been collected and prepared (instrument response removed, filtering to acceptable-signal band, determining peak and spectral parameter values, quality assurance, etc.) for the database. Geologic Survey of Canada (GSC) strong motion recordings, previously not available, have also been added to the NGA East database. The additional earthquakes increase the number of ground motion recordings in the 10 - 100 km range, particularly from the 2008 M5.2 Mt. Carmel, IL event, and the 2005 M4.7 Riviere du Loup and 2010 M5.0 Val des Bois earthquakes in Quebec, Canada. The goal is to complete the ENA database and make it available in 2011 followed by a SCR database in 2012. Comparisons of ground motion observations from four recent M5 ENA earthquakes with current ENA ground motion prediction equations (GMPEs) suggest that current GMPEs, as a group, reasonably agree with M5 observations at short periods, particularly at distances less than 200 km. However, at one second, current GMPEs over predict M5 ground motion observations. The 2001 M7.6 Bhuj, India, earthquake provides some constraint at large magnitudes, as geology and regional attenuation is analogous to ENA. Cramer and Kumar, 2003, have

  14. Flow Characteristics of Tidewater Glaciers in Greenland and Alaska using Ground-Based LiDAR

    Science.gov (United States)

    Finnegan, D. C.; Stearns, L. A.; Hamilton, G. S.; O'Neel, S.

    2010-12-01

    LiDAR scanning systems have been employed to characterize and quantify multi-temporal glacier and ice sheet changes for nearly three decades. Until recently, LiDAR scanning systems were limited to airborne and space-based platforms which come at a significant cost to deploy and are limited in spatial and temporal sampling capabilities necessary to compare with in-situ field measurements. Portable ground-based LiDAR scanning systems are now being used as a glaciological tool. We discuss research efforts to employ ground-based near-infrared LiDAR systems at two differing tidewater glacier systems in the spring of 2009; Helheim Glacier in southeast Greenland and Columbia Glacier in southeast Alaska. Preliminary results allow us to characterize short term displacement rates and detailed observations of calving processes. These results highlight the operational limitations and capabilities of commercially available LiDAR systems, and allow us to identify optimal operating characteristics for monitoring small to large-scale tidewater glaciers in near real-time. Furthermore, by identifying the operational limitations of these sensors it allows for optimal design characteristics of new sensors necessary to meet ground-based calibration and validation requirements of ongoing scientific missions.

  15. Entry Dispersion Analysis for the Hayabusa Spacecraft using Ground Based Optical Observation

    CERN Document Server

    Yamaguchi, T; Yagi, M; Tholen, D J

    2011-01-01

    Hayabusa asteroid explorer successfully released the sample capsule to Australia on June 13, 2010. Since the Earth reentry phase of sample return was critical, many backup plans for predicting the landing location were prepared. This paper investigates the reentry dispersion using ground based optical observation as a backup observation for radiometric observation. Several scenarios are calculated and compared for the reentry phase of the Hayabusa to evaluate the navigation accuracy of the ground-based observation. The optical observation doesn't require any active reaction from a spacecraft, thus these results show that optical observations could be a steady backup strategy even if a spacecraft had some trouble. We also evaluate the landing dispersion of the Hayabusa only with the optical observation.

  16. Ground-based walking training improves quality of life and exercise capacity in COPD.

    Science.gov (United States)

    Wootton, Sally L; Ng, L W Cindy; McKeough, Zoe J; Jenkins, Sue; Hill, Kylie; Eastwood, Peter R; Hillman, David R; Cecins, Nola; Spencer, Lissa M; Jenkins, Christine; Alison, Jennifer A

    2014-10-01

    This study was designed to determine the effect of ground-based walking training on health-related quality of life and exercise capacity in people with chronic obstructive pulmonary disease (COPD). People with COPD were randomised to either a walking group that received supervised, ground-based walking training two to three times a week for 8-10 weeks, or a control group that received usual medical care and did not participate in exercise training. 130 out of 143 participants (mean±sd age 69±8 years, forced expiratory volume in 1 s 43±15% predicted) completed the study. Compared to the control group, the walking group demonstrated greater improvements in the St George's Respiratory Questionnaire total score (mean difference -6 points (95% CI -10- -2), pimproves quality of life and endurance exercise capacity in people with COPD.

  17. Coherent receiving efficiency in satellite-ground coherent laser communication system based on analysis of polarization

    Science.gov (United States)

    Hao, Shiqi; Zhang, Dai; Zhao, Qingsong; Wang, Lei; Zhao, Qi

    2017-06-01

    Aimed at analyzing the coherent receiving efficiency of a satellite-ground coherent laser communication system, polarization state of the received light is analyzed. We choose the circularly polarized, partially coherent laser as transmitted light source. The analysis process includes 3 parts. Firstly, an theoretical model to analyze received light's polarization state is constructed based on Gaussian-Schell model (GSM) and cross spectral density function matrix. Then, analytic formulas to calculate coherent receiving efficiency are derived in which both initial ellipticity modification and deflection angle between polarization axes of the received light and the intrinsic light are considered. At last, numerical simulations are operated based on our study. The research findings investigate variations of polarization state and obtain analytic formulas to calculate the coherent receiving efficiency. Our study has theoretical guiding significances in construction and optimization of satellite-ground coherent laser communication system.

  18. Techniques to extend the reach of ground based gravitational wave detectors

    Science.gov (United States)

    Dwyer, Sheila

    2016-03-01

    While the current generation of advanced ground based detectors will open the gravitational wave universe to observation, ground based interferometry has the potential to extend the reach of these observatories to high redshifts. Several techniques have the potential to improve the advanced detectors beyond design sensitivity, including the use of squeezed light, upgraded suspensions, and possibly new optical coatings, new test mass materials, and cryogenic suspensions. To improve the sensitivity by more than a factor of 10 compared to advanced detectors new, longer facilities will be needed. Future observatories capable of hosting interferometers 10s of kilometers long have the potential to extend the reach of gravitational wave astronomy to cosmological distances, enabling detection of binary inspirals from throughout the history of star formation.

  19. Ground-based near-infrared imaging of the HD141569 circumstellar disk

    CERN Document Server

    Boccaletti, A; Marchis, F; Hanh, J

    2003-01-01

    We present the first ground-based near-infrared image of the circumstellar disk around the post-Herbig Ae/Be star HD141569A initially detected with the HST. Observations were carried out in the near-IR (2.2 $\\mu$m) at the Palomar 200-inch telescope using the adaptive optics system PALAO. The main large scale asymmetric features of the disk are detected on our ground-based data. In addition, we measured that the surface brightness of the disk is slightly different than that derived by HST observations (at 1.1 $\\mu$m and 1.6 $\\mu$m). We interpret this possible color-effect in terms of dust properties and derive a minimal

  20. Topographic gradient based site characterization in India complemented by strong ground-motion spectral attributes

    KAUST Repository

    Nath, Sankar Kumar

    2013-12-01

    We appraise topographic-gradient approach for site classification that employs correlations between 30. m column averaged shear-wave velocity and topographic gradients. Assessments based on site classifications reported from cities across India indicate that the approach is reasonably viable at regional level. Additionally, we experiment three techniques for site classification based on strong ground-motion recordings, namely Horizontal-to-Vertical Spectral Ratio (HVSR), Response Spectra Shape (RSS), and Horizontal-to-Vertical Response Spectral Ratio (HVRSR) at the strong motion stations located across the Himalayas and northeast India. Statistical tests on the results indicate that these three techniques broadly differentiate soil and rock sites while RSS and HVRSR yield better signatures. The results also support the implemented site classification in the light of strong ground-motion spectral attributes observed in different parts of the globe. © 2013 Elsevier Ltd.

  1. Neural Correlates of Auditory Figure-Ground Segregation Based on Temporal Coherence

    Science.gov (United States)

    Teki, Sundeep; Barascud, Nicolas; Picard, Samuel; Payne, Christopher; Griffiths, Timothy D.; Chait, Maria

    2016-01-01

    To make sense of natural acoustic environments, listeners must parse complex mixtures of sounds that vary in frequency, space, and time. Emerging work suggests that, in addition to the well-studied spectral cues for segregation, sensitivity to temporal coherence—the coincidence of sound elements in and across time—is also critical for the perceptual organization of acoustic scenes. Here, we examine pre-attentive, stimulus-driven neural processes underlying auditory figure-ground segregation using stimuli that capture the challenges of listening in complex scenes where segregation cannot be achieved based on spectral cues alone. Signals (“stochastic figure-ground”: SFG) comprised a sequence of brief broadband chords containing random pure tone components that vary from 1 chord to another. Occasional tone repetitions across chords are perceived as “figures” popping out of a stochastic “ground.” Magnetoencephalography (MEG) measurement in naïve, distracted, human subjects revealed robust evoked responses, commencing from about 150 ms after figure onset that reflect the emergence of the “figure” from the randomly varying “ground.” Neural sources underlying this bottom-up driven figure-ground segregation were localized to planum temporale, and the intraparietal sulcus, demonstrating that this area, outside the “classic” auditory system, is also involved in the early stages of auditory scene analysis.” PMID:27325682

  2. Single Phase-to-Ground Fault Line Identification and Section Location Method for Non-Effectively Grounded Distribution Systems Based on Signal Injection

    Institute of Scientific and Technical Information of China (English)

    PAN Zhencun; WANG Chengshan; CONG Wei; ZHANG Fan

    2008-01-01

    A diagnostic signal current trace detecting based single phase-to-ground fault line identifica- tion and section location method for non-effectively grounded distribution systems is presented in thisi oaper. A special diagnostic signal current is injected into the fault distribution system, and then it is de- tected at the outlet terminals to identify the fault line and at the sectionalizing or branching point along the fault line to locate the fault section. The method has been put into application in actual distribution network and field experience shows that it can identify the fault line and locate the fault section correctly and effectively.

  3. Seismic Response of Base-Isolated Structures under Multi-component Ground Motion Excitation

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    An analysis of a base-isolated structure for multi-component random ground motion is presented. The mean square response of the system is obtained under different parametric variations. The effectiveness of main parameters and the torsional component during an earthquake is quantified with the help of the response ratio and the root mean square response with and without base isolation. It is observed that the base isolation has considerable influence on the response and the effect of the torsional component is not ignored.

  4. CoRoT and asteroseismology. Preparatory work and simultaneous ground-based monitoring

    CERN Document Server

    Poretti, Ennio; Uytterhoeven, Katrien; Cutispoto, Giuseppe; Distefano, Elisa; Romano, Paolo

    2007-01-01

    The successful launch of the CoRoT (COnvection, ROtation and planetary Transits) satellite opens a new era in asteroseismology. The space photometry is complemented by high-resolution spectroscopy and multicolour photometry from ground, to disclose the pulsational content of the asteroseismic targets in the most complete way. Some preliminary results obtained with both types of data are presented. The paper is based on observations collected at S. Pedro Martir, Serra La Nave, La Silla, and Telescopio Nazionale Galileo Observatories.

  5. Investigating the long-term evolution of subtropical ozone profiles applying ground-based FTIR spectrometry

    OpenAIRE

    García, O.E.; Schneider, M; A. Redondas; Y. González; Hase, F.; Blumenstock, T.; Sepúlveda, E.

    2012-01-01

    This study investigates the long-term evolution of subtropical ozone profile time series (1999–2010) obtained from ground-based FTIR (Fourier Transform InfraRed) spectrometry at the Izaña Observatory ozone super-site. Different ozone retrieval strategies are examined, analysing the influence of an additional temperature retrieval and different constraints. The theoretical assessment reveals that the FTIR system is able to resolve four independent ozone layers with a precision of better than 6...

  6. Space Fence Ground-Based Radar System Increment 1 (Space Fence Inc 1)

    Science.gov (United States)

    2015-12-01

    Selected Acquisition Report (SAR) RCS: DD-A&T(Q&A)823-438 Space Fence Ground-Based Radar System Increment 1 (Space Fence Inc 1) As of FY 2017...11 Track to Budget 17 Cost and Funding 18 Low Rate Initial Production 23 Foreign Military Sales 24 Nuclear Costs 24 Unit Cost...Document CLIN - Contract Line Item Number CPD - Capability Production Document CY - Calendar Year DAB - Defense Acquisition Board DAE - Defense Acquisition

  7. A Ground-Based Validation System of Teleoperation for a Space Robot

    OpenAIRE

    Xueqian Wang; Houde Liu; Wenfu Xu; Bin Liang; Yingchun Zhang

    2012-01-01

    Teleoperation of space robots is very important for future on‐orbit service. In order to assure the task is accomplished successfully, ground experiments are required to verify the function and validity of the teleoperation system before a space robot is launched. In this paper, a ground‐based validation subsystem is developed as a part of a teleoperation system. The subsystem is mainly composed of four parts: the input verification module, the onboard verification module, the dynamic and ima...

  8. NASA Requirements for Ground-Based Pressure Vessels and Pressurized Systems (PVS). Revision C

    Science.gov (United States)

    Greulich, Owen Rudolf

    2017-01-01

    The purpose of this document is to ensure the structural integrity of PVS through implementation of a minimum set of requirements for ground-based PVS in accordance with this document, NASA Policy Directive (NPD) 8710.5, NASA Safety Policy for Pressure Vessels and Pressurized Systems, NASA Procedural Requirements (NPR) 8715.3, NASA General Safety Program Requirements, applicable Federal Regulations, and national consensus codes and standards (NCS).

  9. The Gaia Era: synergy between space missions and ground based surveys

    CERN Document Server

    Vallenari, A

    2008-01-01

    The Gaia mission is expected to provide highly accurate astrometric, photometric, and spectroscopic measurements for about $10^9$ objects. Automated classification of detected sources is a key part of the data processing. Here a few aspects of the Gaia classification process are presented. Information from other surveys at longer wavelengths, and from follow-up ground based observations will be complementary to Gaia data especially at faint magnitudes, and will offer a great opportunity to understand our Galaxy.

  10. First-generation Science Cases for Ground-based Terahertz Telescopes

    CERN Document Server

    Hirashita, Hiroyuki; Matsushita, Satoki; Takakuwa, Shigehisa; Nakamura, Masanori; Asada, Keiichi; Liu, Hauyu Baobab; Urata, Yuji; Wang, Ming-Jye; Wang, Wei-Hao; Takahashi, Satoko; Tang, Ya-Wen; Chang, Hsian-Hong; Huang, Kuiyun; Morata, Oscar; Otsuka, Masaaki; Lin, Kai-Yang; Tsai, An-Li; Lin, Yen-Ting; Srinivasan, Sundar; Martin-Cocher, Pierre; Pu, Hung-Yi; Kemper, Francisca; Patel, Nimesh; Grimes, Paul; Huang, Yau-De; Han, Chih-Chiang; Huang, Yen-Ru; Nishioka, Hiroaki; Lin, Lupin Chun-Che; Zhang, Qizhou; Keto, Eric; Burgos, Roberto; Chen, Ming-Tang; Inoue, Makoto; Ho, Paul T P

    2015-01-01

    Ground-based observations at terahertz (THz) frequencies are a newly explorable area of astronomy for the next ten years. We discuss science cases for a first-generation 10-m class THz telescope, focusing on the Greenland Telescope as an example of such a facility. We propose science cases and provide quantitative estimates for each case. The largest advantage of ground-based THz telescopes is their higher angular resolution (~ 4 arcsec for a 10-m dish), as compared to space or airborne THz telescopes. Thus, high-resolution mapping is an important scientific argument. In particular, we can isolate zones of interest for Galactic and extragalactic star-forming regions. The THz windows are suitable for observations of high-excitation CO lines and [N II] 205 um lines, which are scientifically relevant tracers of star formation and stellar feedback. Those lines are the brightest lines in the THz windows, so that they are suitable for the initiation of ground-based THz observations. THz polarization of star-forming...

  11. Interactive dynamic three-dimensional scene for the ground-based three-dimensional display

    Science.gov (United States)

    Hou, Peining; Sang, Xinzhu; Guo, Nan; Chen, Duo; Yan, Binbin; Wang, Kuiru; Dou, Wenhua; Xiao, Liquan

    2016-10-01

    Three-dimensional (3D) displays provides valuable tools for many fields, such as scientific experiment, education, information transmission, medical imaging and physical simulation. Ground based 360° 3D display with dynamic and controllable scene can find some special applications, such as design and construction of buildings, aeronautics, military sand table and so on. It can be utilized to evaluate and visualize the dynamic scene of the battlefield, surgical operation and the 3D canvas of art. In order to achieve the ground based 3D display, the public focus plane should be parallel to the camera's imaging planes, and optical axes should be offset to the center of public focus plane in both vertical and horizontal directions. Virtual cameras are used to display 3D dynamic scene with Unity 3D engine. Parameters of virtual cameras for capturing scene are designed and analyzed, and locations of virtual cameras are determined by the observer's eye positions in the observing space world. An interactive dynamic 3D scene for ground based 360° 3D display is demonstrated, which provides high-immersion 3D visualization.

  12. Intercomparison of ground-based ozone and NO2 measurements during the MANTRA 2004 campaign

    Directory of Open Access Journals (Sweden)

    K. Strong

    2007-11-01

    Full Text Available The MANTRA (Middle Atmosphere Nitrogen TRend Assessment 2004 campaign took place in Vanscoy, Saskatchewan, Canada (52° N, 107° W from 3 August to 15 September, 2004. In support of the main balloon launch, a suite of five zenith-sky and direct-Sun-viewing UV-visible ground-based spectrometers was deployed, primarily measuring ozone and NO2 total columns. Three Fourier transform spectrometers (FTSs that were part of the balloon payload also performed ground-based measurements of several species, including ozone. Ground-based measurements of ozone and NO2 differential slant column densities from the zenith-viewing UV-visible instruments are presented herein. They are found to partially agree within NDACC (Network for the Detection of Atmospheric Composition Change standards for instruments certified for process studies and satellite validation. Vertical column densities of ozone from the zenith-sky UV-visible instruments, the FTSs, a Brewer spectrophotometer, and ozonesondes are compared, and found to agree within the combined error estimates of the instruments (15%. NO2 vertical column densities from two of the UV-visible instruments are compared, and are also found to agree within combined error (15%.

  13. Limitation of Ground-based Estimates of Solar Irradiance Due to Atmospheric Variations

    Science.gov (United States)

    Wen, Guoyong; Cahalan, Robert F.; Holben, Brent N.

    2003-01-01

    The uncertainty in ground-based estimates of solar irradiance is quantitatively related to the temporal variability of the atmosphere's optical thickness. The upper and lower bounds of the accuracy of estimates using the Langley Plot technique are proportional to the standard deviation of aerosol optical thickness (approx. +/- 13 sigma(delta tau)). The estimates of spectral solar irradiance (SSI) in two Cimel sun photometer channels from the Mauna Loa site of AERONET are compared with satellite observations from SOLSTICE (Solar Stellar Irradiance Comparison Experiment) on UARS (Upper Atmospheric Research Satellite) for almost two years of data. The true solar variations related to the 27-day solar rotation cycle observed from SOLSTICE are about 0.15% at the two sun photometer channels. The variability in ground-based estimates is statistically one order of magnitude larger. Even though about 30% of these estimates from all Level 2.0 Cimel data fall within the 0.4 to approx. 0.5% variation level, ground-based estimates are not able to capture the 27-day solar variation observed from SOLSTICE.

  14. Kepler and Ground-based Transits of the Exo-Neptune HAT-P-11b

    CERN Document Server

    Deming, Drake; Jackson, Brian; Peterson, Steven W; Agol, Eric; Knutson, Heather A; Jennings, Donald E; Haase, Flynn; Bays, Kevin

    2011-01-01

    We analyze 26 archival Kepler transits of the exo-Neptune HAT-P-11b, supplemented by ground-based transits observed in the blue (B-band) and near-IR (J-band). Both the planet and host star are smaller than previously believed; our analysis yields Rp=4.31 +/-0.06 Earth-radii, and Rs = 0.683 +/-0.009 solar radii, both about 3-sigma smaller than the discovery values. Our ground-based transit data at wavelengths bracketing the Kepler bandpass serve to check the wavelength dependence of stellar limb darkening, and the J-band transit provides a precise and independent constraint on the transit duration. Both the limb darkening and transit duration from our ground-based data are consistent with the new Kepler values for the system parameters. Our smaller radius for the planet implies that its gaseous envelope can be less extensive than previously believed, being very similar to the H-He envelope of GJ436b and Kepler-4b. HAT-P-11 is an active star, and signatures of star spot crossings are ubiquitous in the Kepler tr...

  15. Structure and evolution of Pluto's Atmosphere from ground-based stellar occultations between 2002 and 2015

    Science.gov (United States)

    Meza, Erick; Sicardy, Bruno; Rio de Janeiro occultation team, Granada occultation team, International Occultation and Timing Association

    2016-10-01

    Ground-Based stellar occultations probe Pluto's atmosphere from about 3 km altitude (~ 10 μbar pressure level) up to 260 km altitude (~0.1 μbar). Our main goal is to derive Pluto's atmosphere evolution using thirteen ground-based occultations observed between 2002 and 2015 (plus 2016, if available). We consistently analyze the light curves using the Dias et al. (ApJ 811, 53, 2015) model, and confirm the general pressure increase by a factor of about 1.5 between 2002 and 2015 and a factor of almost three between 1988 and 2015. Implications for Pluto's seasonal evolution will be briefly discussed in the context of the New Horizons (NH) findings.Ground-based-derived temperature profiles will be compared with NH's results, where we use new temperature boundary conditions in our inversion procedures, as given by NH near 260 km altitude. Although the profiles reasonably agree, significant discrepancies are observed both in the deeper stratospheric zone (altitude topographic features revealed by NH.Finally, possible correlations between spike activity in the occultation light-curves and local underlying presence of free nitrogen ice terrains will be investigated.Part of the research leading to these results has received funding from the European Research Council under the European Community's H2020 (2014-2020/ ERC Grant Agreement n 669416 "LUCKY STAR").

  16. Synchronized observations by using the STEREO and the largest ground-based decametre radio telescope

    Science.gov (United States)

    Konovalenko, A. A.; Stanislavsky, A. A.; Rucker, H. O.; Lecacheux, A.; Mann, G.; Bougeret, J.-L.; Kaiser, M. L.; Briand, C.; Zarka, P.; Abranin, E. P.; Dorovsky, V. V.; Koval, A. A.; Mel'nik, V. N.; Mukha, D. V.; Panchenko, M.

    2013-08-01

    We consider the approach to simultaneous (synchronous) solar observations of radio emission by using the STEREO-WAVES instruments (frequency range 0.125-16 MHz) and the largest ground-based low-frequency radio telescope. We illustrate it by the UTR-2 radio telescope implementation (10-30 MHz). The antenna system of the radio telescope is a T-shape-like array of broadband dipoles and is located near the village Grakovo in the Kharkiv region (Ukraine). The third observation point on the ground in addition to two space-based ones improves the space-mission performance capabilities for the determination of radio-emission source directivity. The observational results from the high sensitivity antenna UTR-2 are particularly useful for analysis of STEREO data in the condition of weak event appearances during solar activity minima. In order to improve the accuracy of flux density measurements, we also provide simultaneous observations with a large part of the UTR-2 radio telescope array and its single dipole close to the STEREO-WAVES antennas in sensitivity. This concept has been studied by comparing the STEREO data with ground-based records from 2007-2011 and shown to be effective. The capabilities will be useful in the implementation of new instruments (LOFAR, LWA, MWA, etc.) and during the future Solar Orbiter mission.

  17. Phase-coherent mapping of gravitational-wave backgrounds using ground-based laser interferometers

    CERN Document Server

    Romano, Joseph D; Cornish, Neil J; Gair, Jonathan; Mingarelli, Chiara M F; van Haasteren, Rutger

    2015-01-01

    We extend the formalisms developed in Gair et al. and Cornish and van Haasteren to create maps of gravitational-wave backgrounds using a network of ground-based laser interferometers. We show that in contrast to pulsar timing arrays, which are insensitive to half of the gravitational-wave sky (the curl modes), a network of ground-based interferometers is sensitive to both the gradient and curl components of the background. The spatial separation of a network of interferometers, or of a single interferometer at different times during its rotational and orbital motion around the Sun, allows for recovery of both components. We derive expressions for the response functions of a laser interferometer in the small-antenna limit, and use these expressions to calculate the overlap reduction function for a pair of interferometers. We also construct maximum-likelihood estimates of the + and x-polarization modes of the gravitational-wave sky in terms of the response matrix for a network of ground-based interferometers, e...

  18. A Ground-Based Array to Observe Geospace Electrodynamics During Adverse Space Weather Conditions

    Science.gov (United States)

    Sojka, J. J.; Eccles, J. V.; Rice, D.

    2004-05-01

    Geomagnetic Storms occur with surprising frequency and create adverse space weather conditions. During these periods, our knowledge and ability to specify or forecast in adequate detail for user needs is negligible. Neither experimental observations nor theoretical developments have made a significant new impact on the problem for over two decades. Although we can now map Total Electron Content (TEC) in the ionosphere over a continent with sufficient resolution to see coherent long-lived structures, these do not provide constraints on the geospace electrodynamics that is at the heart of our lack of understanding. We present arguments for the need of a continental deployment of ground-based sensors to stepwise advance our understanding of the geospace electrodynamics when it is most adverse from a space weather perspective and also most frustrating from an understanding of Magnetosphere-Ionosphere coupling. That a continental-scale deployment is more productive at addressing the problem than a realizable global distribution is shown. Each measurement is discussed from the point-of-view of either providing new knowledge or becoming a key for future real-time specification and forecasting for user applications. An example of a storm database from one mid-latitude station for the 31 March 2002 is used as a conceptual point in a ground-based array. The presentation focuses on scientific questions that have eluded a quantitative solution for over three decades and view a ground-based array as an "IGY" type of catalyst for answering these questions.

  19. Lidar-Based Estimates of Above-Ground Biomass in the Continental US and Mexico Using Ground, Airborne, and Satellite Observations

    Science.gov (United States)

    Nelson, Ross; Margolis, Hank; Montesano, Paul; Sun, Guoqing; Cook, Bruce; Corp, Larry; Andersen, Hans-Erik; DeJong, Ben; Pellat, Fernando Paz; Fickel, Thaddeus; Kauffman, Jobriath; Prisley, Stephen

    2016-01-01

    Existing national forest inventory plots, an airborne lidar scanning (ALS) system, and a space profiling lidar system (ICESat-GLAS) are used to generate circa 2005 estimates of total aboveground dry biomass (AGB) in forest strata, by state, in the continental United States (CONUS) and Mexico. The airborne lidar is used to link ground observations of AGB to space lidar measurements. Two sets of models are generated, the first relating ground estimates of AGB to airborne laser scanning (ALS) measurements and the second set relating ALS estimates of AGB (generated using the first model set) to GLAS measurements. GLAS then, is used as a sampling tool within a hybrid estimation framework to generate stratum-, state-, and national-level AGB estimates. A two-phase variance estimator is employed to quantify GLAS sampling variability and, additively, ALS-GLAS model variability in this current, three-phase (ground-ALS-space lidar) study. The model variance component characterizes the variability of the regression coefficients used to predict ALS-based estimates of biomass as a function of GLAS measurements. Three different types of predictive models are considered in CONUS to determine which produced biomass totals closest to ground-based national forest inventory estimates - (1) linear (LIN), (2) linear-no-intercept (LNI), and (3) log-linear. For CONUS at the national level, the GLAS LNI model estimate (23.95 +/- 0.45 Gt AGB), agreed most closely with the US national forest inventory ground estimate, 24.17 +/- 0.06 Gt, i.e., within 1%. The national biomass total based on linear ground-ALS and ALS-GLAS models (25.87 +/- 0.49 Gt) overestimated the national ground-based estimate by 7.5%. The comparable log-linear model result (63.29 +/-1.36 Gt) overestimated ground results by 261%. All three national biomass GLAS estimates, LIN, LNI, and log-linear, are based on 241,718 pulses collected on 230 orbits. The US national forest inventory (ground) estimates are based on 119

  20. Optical wireless transmission of 405 nm, 1.45 Gbit/s optical IM/DD-OFDM signals through a 4.8 m underwater channel.

    Science.gov (United States)

    Nakamura, Kazuhiko; Mizukoshi, Izumi; Hanawa, Masanori

    2015-01-26

    In this paper, we experimentally demonstrate wireless transmission of optical intensity modulation/direct detection-orthogonal frequency division multiplexing (IM/DD-OFDM) signals in an underwater channel using a field programmable gate array based real-time transmitter. The real-time transmission of a 405 nm 1.45 Gbit/s optical OFDM signal through a 4.8 m underwater channel with an error vector magnitude of approximately 10% was successfully achieved.

  1. Synthesis and Electrochemical Characterization of M2Mn3O8 (M=Ca,Cu) Compounds and Derivatives

    Energy Technology Data Exchange (ETDEWEB)

    Park, Yong Joon; Doeff, Marca M.

    2005-08-25

    M{sub 2}Mn{sub 3}O{sub 8} (M=Ca{sup 2+}, Cu{sup 2+}) compounds were synthesized and characterized in lithium cells. The M{sup 2+} cations, which reside in the van der Waal's gaps between adjacent sheets of Mn{sub 3}O{sub 8}{sup 4-}, may be replaced chemically (by ion-exchange) or electrochemically with Li. More than 7 Li{sup +}/Cu{sub 2}Mn{sub 3}O{sub 8} may be inserted electrochemically, with concomitant reduction of Cu{sup 2+} to Cu metal, but less Li can be inserted into Ca{sub 2}Mn{sub 3}O{sub 8}. In the case of Cu{sup 2+}, this process is partially reversible when the cell is charged above 3.5 V vs. Li, but intercalation of Cu{sup +} rather than Cu{sup 2+} and Li{sup +}/Cu{sup +} exchange occurs during the subsequent discharge. If the cell potential is kept below 3.4 V, the Li in excess of 4Li{sup +}/Cu{sub 2}Mn{sub 3}O{sub 8} can be cycled reversibly. The unusual mobility of +2 cations in a layered structure has important implications both for the design of cathodes for Li batteries and for new systems that could be based on M{sup 2+} intercalation compounds.

  2. Understanding the Longitudinal Variability of Equatorial Electrodynamics using integrated Ground- and Space-based Observations

    Science.gov (United States)

    Yizengaw, E.; Moldwin, M.; Zesta, E.

    2015-12-01

    The currently funded African Meridian B-Field Education and Research (AMBER) magnetometer array comprises more than thirteen magnetometers stationed globally in the vicinity of geomagnetic equator. One of the main objectives of AMBER network is to understand the longitudinal variability of equatorial electrodynamics as function of local time, magnetic activity, and season. While providing complete meridian observation in the region and filling the largest land-based gap in global magnetometer coverage, the AMBER array addresses two fundamental areas of space physics: first, the processes governing electrodynamics of the equatorial ionosphere as a function of latitude (or L-shell), local time, longitude, magnetic activity, and season, and second, ULF pulsation strength at low/mid-latitude regions and its connection with equatorial electrojet and density fluctuation. The global AMBER network can also be used to augment observations from space-based instruments, such us the triplet SWARM mission and the upcoming ICON missions. Thus, in coordination with space-based and other ground-based observations, the AMBER magnetometer network provides a great opportunity to understand the electrodynamics that governs equatorial ionosphere motions. In this paper we present the longitudinal variability of the equatorial electrodynamics using the combination of instruments onboard SWARM and C/NOFS satellites and ground-based AMBER network. Both ground- and pace-based observations show stronger dayside and evening sector equatorial electrodynamics in the American and Asian sectors compared to the African sector. On the other hand, the African sector is home to stronger and year-round ionospheric bubbles/irregularities compared to the American and Asian sectors. This raises the question if the evening sector equatorial electrodynamics (vertical drift), which is believed to be the main cause for the enhancement of Rayleigh-Taylor (RT) instability growth rate, is stronger in the

  3. Adaptive method for real-time gait phase detection based on ground contact forces.

    Science.gov (United States)

    Yu, Lie; Zheng, Jianbin; Wang, Yang; Song, Zhengge; Zhan, Enqi

    2015-01-01

    A novel method is presented to detect real-time gait phases based on ground contact forces (GCFs) measured by force sensitive resistors (FSRs). The traditional threshold method (TM) sets a threshold to divide the GCFs into on-ground and off-ground statuses. However, TM is neither an adaptive nor real-time method. The threshold setting is based on body weight or the maximum and minimum GCFs in the gait cycles, resulting in different thresholds needed for different walking conditions. Additionally, the maximum and minimum GCFs are only obtainable after data processing. Therefore, this paper proposes a proportion method (PM) that calculates the sums and proportions of GCFs wherein the GCFs are obtained from FSRs. A gait analysis is then implemented by the proposed gait phase detection algorithm (GPDA). Finally, the PM reliability is determined by comparing the detection results between PM and TM. Experimental results demonstrate that the proposed PM is highly reliable in all walking conditions. In addition, PM could be utilized to analyze gait phases in real time. Finally, PM exhibits strong adaptability to different walking conditions.

  4. Pc5 Oscillation Analysis by the Satellite and Ground-Based Data

    Institute of Scientific and Technical Information of China (English)

    A. Potapov; T. Polyushkina; T. L. Zhang; H. Zhao; A. Guglielmi; J. Kultima

    2005-01-01

    Large amplitude Pc5 event was observed in the space and on ground on August 3, 2001, about three hours after contact of the strong discontinuity in the solar wind with the magnetosphere according to data from ACE and Wind satellites. The Pc5 amplitude was as high as 15 nT in the tail of magnetosphere and about 5 nT at the ground based stations. In the magnetosphere Pc5 waves were observed by Cluster and Polar satellites, which occupied positions in the morning part of the near tail at the close field lines but were parted by distance of 11.5 Re, mainly along the x-axis of the GSM coordinate system. Both compressional and transverse components of the Pc5 wave activity were observed in the space, with the transverse component having the larger amplitude. Time delay between the Cluster and Polar satellites was about 8 minutes, which could be interpreted as a wave propagation from the geomagnetic tail to the Earth with the 150km/s group velocity.The ground-based Pc5 activity was analysed by using data from the Image magnetometer network. Doubtless demonstrations of a field line resonant structure were found in variations of amplitude and polarization with latitude. Finnish chain of search coil magnetometers observed modulated Pc1 emission simultaneously with the Pc5 wave train. A possibility of non-linear impact of Pc5 wave energy on the plasma and waves in the magnetosphere is discussed.

  5. Nighttime Aerosol Optical Depth Measurements Using a Ground-based Lunar Photometer

    Science.gov (United States)

    Berkoff, Tim; Omar, Ali; Haggard, Charles; Pippin, Margaret; Tasaddaq, Aasam; Stone, Tom; Rodriguez, Jon; Slutsker, Ilya; Eck, Tom; Holben, Brent; hide

    2015-01-01

    In recent years it was proposed to combine AERONET network photometer capabilities with a high precision lunar model used for satellite calibration to retrieve columnar nighttime AODs. The USGS lunar model can continuously provide pre-atmosphere high precision lunar irradiance determinations for multiple wavelengths at ground sensor locations. When combined with measured irradiances from a ground-based AERONET photometer, atmospheric column transmissions can determined yielding nighttime column aerosol AOD and Angstrom coefficients. Additional demonstrations have utilized this approach to further develop calibration methods and to obtain data in polar regions where extended periods of darkness occur. This new capability enables more complete studies of the diurnal behavior of aerosols, and feedback for models and satellite retrievals for the nighttime behavior of aerosols. It is anticipated that the nighttime capability of these sensors will be useful for comparisons with satellite lidars such as CALIOP and CATS in additional to ground-based lidars in MPLNET at night, when the signal-to-noise ratio is higher than daytime and more precise AOD comparisons can be made.

  6. PROBABILISTIC SEISMIC ASSESSMENT OF BASE-ISOLATED NPPS SUBJECTED TO STRONG GROUND MOTIONS OF TOHOKU EARTHQUAKE

    Directory of Open Access Journals (Sweden)

    AHMER ALI

    2014-10-01

    Full Text Available The probabilistic seismic performance of a standard Korean nuclear power plant (NPP with an idealized isolation is investigated in the present work. A probabilistic seismic hazard analysis (PSHA of the Wolsong site on the Korean peninsula is performed by considering peak ground acceleration (PGA as an earthquake intensity measure. A procedure is reported on the categorization and selection of two sets of ground motions of the Tohoku earthquake, i.e. long-period and common as Set A and Set B respectively, for the nonlinear time history response analysis of the base-isolated NPP. Limit state values as multiples of the displacement responses of the NPP base isolation are considered for the fragility estimation. The seismic risk of the NPP is further assessed by incorporation of the rate of frequency exceedance and conditional failure probability curves. Furthermore, this framework attempts to show the unacceptable performance of the isolated NPP in terms of the probabilistic distribution and annual probability of limit states. The comparative results for long and common ground motions are discussed to contribute to the future safety of nuclear facilities against drastic events like Tohoku.

  7. Hail prevention by ground-based silver iodide generators: Results of historical and modern field projects

    Science.gov (United States)

    Dessens, J.; Sánchez, J. L.; Berthet, C.; Hermida, L.; Merino, A.

    2016-03-01

    The science of hail suppression by silver iodide (AgI) cloud seeding was developed during the second half of the 20th century in laboratory and tested in several research or operational projects using three delivery methods for the ice forming particles: ground generators, aircraft, and rockets. The randomization process for the seeding was often considered as the imperative method for a better evaluation but failed to give firm results, mostly because the projects did not last long enough considering the hazardous occurrence of severe hailfalls, and also probably due to the use of improper hail parameters. At the same time and until now, a continuous long-term research and operational field project (1952-2015) using ground generator networks has been conducted in France under the leadership of the Association Nationale d'Etude et de Lutte contre les Fléaux Atmosphériques (ANELFA), with a control initially based on annual insurance loss-to-risk ratios, then on hailpad data. More recently (2000-2009), a companion ground seeding project was developed in the north of Spain, with control mostly based on microphysical and hailpad data. The present paper, which focuses on hail suppression by ground seeding, reviews the production of the AgI nuclei, their dispersion and measurement in the atmosphere, as well as their observed or simulated effects in clouds. The paper summarizes the results of the main historical projects in Switzerland, Argentina, and North America, and finally concentrates on the current French and Spanish projects, with a review of already published results, complemented by new ones recently collected in Spain. The conclusion, at least for France and Spain, is that if ground seeding is performed starting 3 hours before the hail falls at the ground with a 10-km mesh AgI generator network located in the developing hailstorm areas, each generator burning about 9 g of AgI per hour, the hailfall energy of the most severe hail days is decreased by about 50%.

  8. Comparison of Thermal Structure Results from Venus Express and Ground Based Observations since Vira

    Science.gov (United States)

    Limaye, Sanjay

    2016-07-01

    An international team was formed in 2013 through the International Space Studies Institute (Bern, Switzerland) to compare recent results of the Venus atmospheric thermal structure from spacecraft and ground based observations made since the Venus International Reference Atmosphere (VIRA) was developed (Kliore et al., 1985, Keating et al., 1985). Five experiments on European Space Agency's Venus Express orbiter mission have yielded results on the atmospheric structure during is operational life (April 2006 - November 2014). Three of these were from occultation methods: at near infrared wavelengths from solar occultations, (SOIR, 70 - 170 km), at ultraviolet wavelengths from stellar occultations (SPICAV, 90-140 km), and occultation of the VEx-Earth radio signal (VeRa, 40-90 km). In-situ drag measurements from three different techniques (accelerometry, torque, and radio tracking, 130 - 200 km) were also obtained using the spacecraft itself while passive infrared remote sensing was used by the VIRTIS experiment (70 - 120 km). The only new data in the -40-70 km altitude range are from radio occultation, as no new profiles of the deep atmosphere have been obtained since the VeGa 2 lander measurements in 1985 (not included in VIRA). Some selected ground based results available to the team were also considered by team in the inter comparisons. The temperature structure in the lower thermosphere from disk resolved ground based observations (except for one ground based investigation), is generally consistent with the Venus Express results. These experiments sampled at different periods, at different locations and at different local times and have different vertical and horizontal resolution and coverage. The data were therefore binned in latitude and local time bins and compared, ignoring temporal variations over the life time of the Venus Express mission and assumed north-south symmetry. Alternating warm and cooler layers are present in the 120-160 altitude range in results

  9. A Terminal Guidance Law Based on Motion Camouflage Strategy of Air-to-Ground Missiles

    Directory of Open Access Journals (Sweden)

    Chang-sheng Gao

    2016-01-01

    Full Text Available A guidance law for attacking ground target based on motion camouflage strategy is proposed in this paper. According to the relative position between missile and target, the dual second-order dynamics model is derived. The missile guidance condition is given by analyzing the characteristic of motion camouflage strategy. Then, the terminal guidance law is derived by using the relative motion of missile and target and the guidance condition. In the process of derivation, the three-dimensional guidance law could be designed in a two-dimensional plane and the difficulty of guidance law design is reduced. A two-dimensional guidance law for three-dimensional space is derived by bringing the estimation for target maneuver. Finally, simulation for the proposed guidance law is taken and compared with pure proportional navigation. The simulation results demonstrate that the proposed guidance law can be applied to air-to-ground missiles.

  10. Multiscale Recognition Algorithm for Eye Ground Texture Based on Fusion Threshold Equalization

    Directory of Open Access Journals (Sweden)

    Zhongsheng Qiu

    2014-09-01

    Full Text Available The eye ground texture is disturbed by non ideal imaging factor such as noise, it will affect the clinical diagnosis in practice, an improved multi scale retina eye ground texture recognition algorithm is proposed based on fusion area threshold. The nonlinear sampling multi-scale transform is used to analyze the geometric space coefficient of retinal vessels with multi direction and shift invariant features, the regional threshold filtering is integrated, it is used to suppress the effect of non-uniform blocks for texture recognition. The maximum likelihood local mean standard deviation analysis is used for texture parameters estimation and recognition. The noise reduced greatly, accurate identification of texture feature is obtained. Simulation results show that the algorithm can well characterize the retinal vascular texture, it has good performance in different texture feature recognition, the recognition accuracy is improved, and it has good robustness.

  11. Airborne and ground based lidar measurements of the atmospheric pressure profile

    Science.gov (United States)

    Korb, C. Laurence; Schwemmer, Geary K.; Dombrowski, Mark; Weng, Chi Y.

    1989-01-01

    The first high accuracy remote measurements of the atmospheric pressure profile have been made. The measurements were made with a differential absorption lidar system that utilizes tunable alexandrite lasers. The absorption in the trough between two lines in the oxygen A-band near 760 nm was used for probing the atmosphere. Measurements of the two-dimensional structure of the pressure field were made in the troposphere from an aircraft looking down. Also, measurements of the one-dimensional structure were made from the ground looking up. Typical pressure accuracies for the aircraft measurements were 1.5-2 mbar with a 30-m vertical resolution and a 100-shot average (20 s), which corresponds to a 2-km horizontal resolution. Typical accuracies for the upward viewing ground based measurements were 2.0 mbar for a 30-m resolution and a 100-shot average.

  12. Finite Volume Based Computer Program for Ground Source Heat Pump System

    Energy Technology Data Exchange (ETDEWEB)

    Menart, James A. [Wright State University

    2013-02-22

    This report is a compilation of the work that has been done on the grant DE-EE0002805 entitled ?Finite Volume Based Computer Program for Ground Source Heat Pump Systems.? The goal of this project was to develop a detailed computer simulation tool for GSHP (ground source heat pump) heating and cooling systems. Two such tools were developed as part of this DOE (Department of Energy) grant; the first is a two-dimensional computer program called GEO2D and the second is a three-dimensional computer program called GEO3D. Both of these simulation tools provide an extensive array of results to the user. A unique aspect of both these simulation tools is the complete temperature profile information calculated and presented. Complete temperature profiles throughout the ground, casing, tube wall, and fluid are provided as a function of time. The fluid temperatures from and to the heat pump, as a function of time, are also provided. In addition to temperature information, detailed heat rate information at several locations as a function of time is determined. Heat rates between the heat pump and the building indoor environment, between the working fluid and the heat pump, and between the working fluid and the ground are computed. The heat rates between the ground and the working fluid are calculated as a function time and position along the ground loop. The heating and cooling loads of the building being fitted with a GSHP are determined with the computer program developed by DOE called ENERGYPLUS. Lastly COP (coefficient of performance) results as a function of time are provided. Both the two-dimensional and three-dimensional computer programs developed as part of this work are based upon a detailed finite volume solution of the energy equation for the ground and ground loop. Real heat pump characteristics are entered into the program and used to model the heat pump performance. Thus these computer tools simulate the coupled performance of the ground loop and the heat pump

  13. Recovery Act: Finite Volume Based Computer Program for Ground Source Heat Pump Systems

    Energy Technology Data Exchange (ETDEWEB)

    James A Menart, Professor

    2013-02-22

    This report is a compilation of the work that has been done on the grant DE-EE0002805 entitled Finite Volume Based Computer Program for Ground Source Heat Pump Systems. The goal of this project was to develop a detailed computer simulation tool for GSHP (ground source heat pump) heating and cooling systems. Two such tools were developed as part of this DOE (Department of Energy) grant; the first is a two-dimensional computer program called GEO2D and the second is a three-dimensional computer program called GEO3D. Both of these simulation tools provide an extensive array of results to the user. A unique aspect of both these simulation tools is the complete temperature profile information calculated and presented. Complete temperature profiles throughout the ground, casing, tube wall, and fluid are provided as a function of time. The fluid temperatures from and to the heat pump, as a function of time, are also provided. In addition to temperature information, detailed heat rate information at several locations as a function of time is determined. Heat rates between the heat pump and the building indoor environment, between the working fluid and the heat pump, and between the working fluid and the ground are computed. The heat rates between the ground and the working fluid are calculated as a function time and position along the ground loop. The heating and cooling loads of the building being fitted with a GSHP are determined with the computer program developed by DOE called ENERGYPLUS. Lastly COP (coefficient of performance) results as a function of time are provided. Both the two-dimensional and three-dimensional computer programs developed as part of this work are based upon a detailed finite volume solution of the energy equation for the ground and ground loop. Real heat pump characteristics are entered into the program and used to model the heat pump performance. Thus these computer tools simulate the coupled performance of the ground loop and the heat pump. The

  14. Boost-Phase ballistic missile trajectory estimation with ground based radar

    Institute of Scientific and Technical Information of China (English)

    Tang Yuyan; Huang Peikang

    2006-01-01

    A conditional boost-phase trajectory estimation method based on ballistic missile (BM) information database and classification is developed to estimate and predict boos-phase BM trajectory. The main uncertain factors to describe BM dynamics equation are reduced to the control law of trajectory pitch angle in boost-phase. After the BM mass at the beginning of estimation, the BM attack angle and the modification of engine thrust denoting BM acceleration are modeled reasonably, the boost-phase BM trajectory estimation with ground based radar is well realized. The validity of this estimation method is testified by computer simulation with a typical example.

  15. (Environmental investigation of ground water contamination at Wright- Patterson Air Force Base, Ohio)

    Energy Technology Data Exchange (ETDEWEB)

    1991-10-01

    This Health and Safety Plan (HSP) was developed for the Environmental Investigation of Ground-water Contamination Investigation at Wright-Patterson Air Force Base near Dayton, Ohio, based on the projected scope of work for the Phase 1, Task 4 Field Investigation. The HSP describes hazards that may be encountered during the investigation, assesses the hazards, and indicates what type of personal protective equipment is to be used for each task performed. The HSP also addresses the medical monitoring program, decontamination procedures, air monitoring, training, site control, accident prevention, and emergency response.

  16. Retrieving the aerosol lidar ratio profile by combining ground- and space-based elastic lidars.

    Science.gov (United States)

    Feiyue, Mao; Wei, Gong; Yingying, Ma

    2012-02-15

    The aerosol lidar ratio is a key parameter for the retrieval of aerosol optical properties from elastic lidar, which changes largely for aerosols with different chemical and physical properties. We proposed a method for retrieving the aerosol lidar ratio profile by combining simultaneous ground- and space-based elastic lidars. The method was tested by a simulated case and a real case at 532 nm wavelength. The results demonstrated that our method is robust and can obtain accurate lidar ratio and extinction coefficient profiles. Our method can be useful for determining the local and global lidar ratio and validating space-based lidar datasets.

  17. The laser calibration system for the STACEE ground-based gamma ray detector

    CERN Document Server

    Hanna, D

    2002-01-01

    We describe the design and performance of the laser system used for calibration monitoring of components of the STACEE detector. STACEE is a ground based gamma ray detector which uses the heliostats of a solar power facility to collect and focus Cherenkov light onto a system of secondary optics and photomultiplier tubes. To monitor the gain and check the linearity and timing properties of the phototubes and associated electronics, a system based on a dye laser, neutral density filters and optical fibres has been developed. In this paper we describe the system and present some results from initial tests made with it.

  18. Advanced ground-based gravitational-wave detectors' potential to detect generic deviations from general relativity

    CERN Document Server

    Narikawa, Tatsuya

    2016-01-01

    We discuss the potential of the advanced ground-based gravitational-wave detectors, such as LIGO, Virgo, and KAGRA, to detect generic deviations of gravitational waveforms from the prediction of General Relativity. We use the parameterized post-Einsteinian formalism to characterize the deviations, and assess how much magnitude of the deviations are detectable by using an approximate decision scheme based on Bayesian statistics. We find that there exist detectable regions of the parameterized post-Einsteinian parameters by using a single gravitational wave event. The regions are not excluded by currently existing binary pulsar observations for the parameterized post-Einsteinian parameters at higher post-Newtonian order.

  19. Global Fine Particulate Matter Concentrations and Trends Inferred from Satellite Observations, Modeling, and Ground-Based Measurements

    Science.gov (United States)

    Martin, Randall; van Donkelaar, Aaron; Boys, Brian; Philip, Sajeev; Lee, Colin; Snider, Graydon; Weagle, Crystal

    2014-05-01

    Outdoor fine particulate matter (PM2.5) is a leading environmentally-related cause of premature mortality worldwide. However, ground-level PM2.5 monitors remain sparse in many regions of the world. Satellite remote sensing from MODIS, MISR, and SeaWiFS yields a powerful global data source to address this issue. Global modeling (GEOS-Chem) plays a critical role in relating these observations to ground-level concentrations. The resultant satellite-based estimates of PM2.5 indicate dramatic variation around the world, with implications for global public health. A new ground-based aerosol network (SPARTAN) offers valuable measurements to understand the relationship between satellite observations of aerosol optical depth and ground-level PM2.5 concentrations. This talk will highlight recent advances in combining satellite remote sensing, global modeling, and ground-based measurements to improve understanding of global population exposure to outdoor fine particulate matter.

  20. Displacement response analysis of base-isolated buildings subjected to near-fault ground motions with velocity pulse

    Science.gov (United States)

    He, Qiumei; Li, Xiaojun; Yang, Yu; Liu, Aiwen; Li, Yaqi

    2016-04-01

    In order to study the influence of the velocity pulse to seismic displacement response of base-isolated buildings and the differences of the influent of the two types of near-fault ground motions with velocity pulse to seismic response of base-isolated buildings, the seismic responses are analyzed by three dimensional finite element models for three base-isolated buildings, 4 stories, 9 stories and 14 stories. In this study, comparative analyses were done for the seismic displacement responses of the base-isolated structures under 6 near-fault ground motion records with velocity pulse and no velocity pulse, in which, 6 artificial ground motion time histories with same elastic response spectrum as the 6 near-fault ground motion records are used as the ground motion with no velocity pulse. This study indicates that under the ground motions with velocity pulse the seismic displacement response of base-isolated buildings is significantly increased than the ground motions with no velocity pulse. To the median-low base-isolated buildings, the impact of forward directivity pulses is bigger than fling-step pulses. To the high base-isolated buildings, the impact of fling-step pulses is bigger than forward directivity pulses. The fling-step pulses lead to large displacement response in the lower stories. This work has been supported by the National Natural Science Foundation of China (Grant No.51408560)

  1. Coordinated Ground- and Space-based Multispectral Campaign to Study Equatorial Spread-F Formation

    Science.gov (United States)

    Finn, S. C.; Geddes, G.; Aryal, S.; Stephan, A. W.; Budzien, S. A.; Duggirala, P. R.; Chakrabarti, S.; Valladares, C.

    2016-12-01

    We present a concept for a multispectral campaign using coordinated data from state-of-the-art instruments aboard the International Space Station (ISS) and multiple ground-based spectrometers and digisondes deployed at low-latitudes to study the formation and development of Equatorial Spread-F (ESF). This extended observational campaign utilizes ultraviolet, visible, and radio measurements to develop a predictive capability for ESF and to study the coupling of the ionosphere-thermosphere (I-T) system during geomagnetically quiet and disturbed times. The ground-based instruments will be deployed in carefully chosen locations in the American and Indian sectors while the space-based data will provide global coverage spanning all local times and longitudes within ±51° geographic latitudes. The campaign, over an extended period covering a range of geophysical conditions, will provide the extensive data base necessary to address the important science questions. The space-based instrument suite consists of the Limb-imaging Ionospheric and Thermospheric Extreme-ultraviolet Spectrograph (LITES) and the GPS Radio Occultation and Ultraviolet Photometry-Colocated (GROUP-C) instruments, scheduled to launch to the ISS in November 2016. LITES is a compact imaging spectrograph for remote sensing of the upper atmosphere and ionosphere from 60 to 140nm and GROUP-C has a nadir-viewing FUV photometer. The ground-based instruments to be deployed for this campaign are three high-resolution imaging spectrographs capable of continuous round-the-clock airglow observations: Multiwavelength Imaging Spectrograph using Echelle grating (MISE) in India and two High Throughput and Multi-slit Imaging Spectrographs (HiT&MIS) to be deployed in Colombia and Argentina, the Low-Latitude Ionosphere Sensor Network (LISN), and the Global Ionospheric Radio Observatory (GIRO) digisondes network. We present data from the ground-based instruments, initial results from the LITES and GROUP-C instruments on

  2. A Little Knowledge of Ground Motion: Explaining 3-D Physics-Based Modeling to Engineers

    Science.gov (United States)

    Porter, K.

    2014-12-01

    Users of earthquake planning scenarios require the ground-motion map to be credible enough to justify costly planning efforts, but not all ground-motion maps are right for all uses. There are two common ways to create a map of ground motion for a hypothetical earthquake. One approach is to map the median shaking estimated by empirical attenuation relationships. The other uses 3-D physics-based modeling, in which one analyzes a mathematical model of the earth's crust near the fault rupture and calculates the generation and propagation of seismic waves from source to ground surface by first principles. The two approaches produce different-looking maps. The more-familiar median maps smooth out variability and correlation. Using them in a planning scenario can lead to a systematic underestimation of damage and loss, and could leave a community underprepared for realistic shaking. The 3-D maps show variability, including some very high values that can disconcert non-scientists. So when the USGS Science Application for Risk Reduction's (SAFRR) Haywired scenario project selected 3-D maps, it was necessary to explain to scenario users—especially engineers who often use median maps—the differences, advantages, and disadvantages of the two approaches. We used authority, empirical evidence, and theory to support our choice. We prefaced our explanation with SAFRR's policy of using the best available earth science, and cited the credentials of the maps' developers and the reputation of the journal in which they published the maps. We cited recorded examples from past earthquakes of extreme ground motions that are like those in the scenario map. We explained the maps on theoretical grounds as well, explaining well established causes of variability: directivity, basin effects, and source parameters. The largest mapped motions relate to potentially unfamiliar extreme-value theory, so we used analogies to human longevity and the average age of the oldest person in samples of

  3. Comparison of OMI UV observations with ground-based measurements at high northern latitudes

    Directory of Open Access Journals (Sweden)

    G. Bernhard

    2015-03-01

    Full Text Available The Dutch-Finnish Ozone Monitoring Instrument (OMI on board NASA's Aura spacecraft provides estimates of erythemal (sunburning ultraviolet (UV dose rates and erythemal daily doses. These data were compared with ground-based measurements at 13 stations located throughout the Arctic and Scandinavia from 60 to 83° N. The study corroborates results from earlier work, but is based on a longer time series (eight vs. two years and considers additional data products, such as the erythemal dose rate at the time of the satellite overpass. Furthermore, systematic errors in satellite UV data resulting from inaccuracies in the surface albedo climatology used in the OMI UV algorithm are systematically assessed. At times when the surface albedo is correctly known, OMI data typically exceed ground-based measurements by 0–11%. When the OMI albedo climatology exceeds the actual albedo, OMI data may be biased high by as much as 55%. In turn, when the OMI albedo climatology is too low, OMI data can be biased low by up to 59%. Such large negative biases may occur when reflections from snow and ice, which increase downwelling UV irradiance, are misinterpreted as reflections from clouds, which decrease the UV flux at the surface. Results suggest that a better OMI albedo climatology would greatly improve the accuracy of OMI UV data products even if year-to-year differences of the actual albedo cannot be accounted for. A pathway for improving the OMI albedo climatology is discussed. Results also demonstrate that ground-based measurements from the center of Greenland, where high, homogenous surface albedo is observed year round, are ideally suited to detect systematic problems or temporal drifts in estimates of surface UV irradiance from space.

  4. Ground-based microwave measuring of middle atmosphere ozone and temperature profiles during sudden stratospheric warming

    Science.gov (United States)

    Feigin, A. M.; Shvetsov, A. A.; Krasilnikov, A. A.; Kulikov, M. Y.; Karashtin, D. A.; Mukhin, D.; Bolshakov, O. S.; Fedoseev, L. I.; Ryskin, V. G.; Belikovich, M. V.; Kukin, L. M.

    2012-12-01

    We carried out the experimental campaign aimed to study the response of middle atmosphere on a sudden stratospheric warming in winter 2011-2012 above Nizhny Novgorod, Russia (56N, 44E). We employed the ground-based microwave complex for remote sensing of middle atmosphere developed in the Institute of Applied Physics of the Russian Academy of Science. The complex combines two room-temperature radiometers, i.e. microwave ozonometer and the stratospheric thermometer. Ozonometer is a heterodyne spectroradiometer, operating in a range of frequencies that include the rotation transition of ozone molecules with resonance frequency 110.8 GHz. Operating frequency range of the stratospheric thermometer is 52.5-5.4 GHz and includes lower frequency edge of 5 mm molecular oxygen absorption bands and among them two relatively weak lines of O2 emission. Digital fast Fourier transform spectrometers developed by "Acqiris" are employed for signal spectral analysis. The spectrometers have frequency range 0.05-1 GHz and realizes the effective resolution about 61 KHz. For retrieval vertical profiles of ozone and temperature from radiometric data we applied novel method based on Bayesian approach to inverse problem solution, which assumed a construction of probability distribution of the characteristics of retrieved profiles with taking into account measurement noise and available a priori information about possible distributions of ozone and temperature in the middle atmosphere. Here we introduce the results of the campaign in comparison with Aura MLS data. Presented data includes one sudden stratospheric warming event which took place in January 13-14 and was accompanied by temperature increasing up to 310 K at 45 km height. During measurement period, ozone and temperature variations were (almost) anti-correlated, and total ozone abundance achieved a local maxima during the stratosphere cooling phase. In general, results of ground-based measurements are in good agreement with

  5. (Environmental investigation of ground water contamination at Wright-Patterson Air Force Base, Ohio)

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, Bill

    1991-10-01

    In April 1990, Wright-Patterson Air Force Base (WPAFB), initiated an investigation to evaluate a potential Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) removal action to prevent, to the extent practicable, the offsite migration of contaminated ground water from WPAFB. WPAFB retained the services of the Environmental Management Operations (EMO) and its principle subcontractor, International Technology Corporation (IT) to complete Phase 1 of the environmental investigation of ground-water contamination at WPAFB. Phase 1 of the investigation involves the short-term evaluation and potential design for a program to remove ground-water contamination that appears to be migrating across the western boundary of Area C, and across the northern boundary of Area B along Springfield Pike. Primarily, Task 4 of Phase 1 focuses on collection of information at the Area C and Springfield Pike boundaries of WPAFB. This Sampling and Analysis Plan (SAP) has been prepared to assist in completion of the Task 4 field investigation and is comprised of the Quality Assurance Project Plan (QAPP) and the Field Sampling Plan (FSP).

  6. Constellation design for earth observation based on the characteristics of the satellite ground track

    Science.gov (United States)

    Luo, Xin; Wang, Maocai; Dai, Guangming; Song, Zhiming

    2017-04-01

    This paper responds to the increasing need for Earth observation missions and deals with the design of Repeating Sun-Synchronous Constellations (RSSCs) which takes into consideration of constellations composed of one or more orbital planes. Based on the mature design approach of Repeating Sun-synchronous orbits, a novel technique to design RSSCs is presented, which takes the second gravitational zonal harmonic into consideration. In order to obtain regular cycles of observation of the Earth by a single satellite, the orbital relationships have to be satisfied firstly are illustrated. Then, by making full analyses of the characteristics of the satellite ground track, orbital parameters are properly calculated to make other satellites pass on the same or different ground track of the single satellite. Last, single-plane or multi-plane constellations are used to improve the repetitions of the observation and the ground resolution. RSSCs allow observing the same region once at the same local time in a solar day and several times at the different local time in a solar day. Therefore, this kind of constellations meets all requirements for the remote sensing applications, which need to observe the same region under the same or different visible conditions. Through various case studies, the calculation technique is successfully demonstrated.

  7. SAR Ground Moving Target Indication Based on Relative Residue of DPCA Processing.

    Science.gov (United States)

    Xu, Jia; Huang, Zuzhen; Yan, Liang; Zhou, Xu; Zhang, Furu; Long, Teng

    2016-10-12

    For modern synthetic aperture radar (SAR), it has much more urgent demands on ground moving target indication (GMTI), which includes not only the point moving targets like cars, truck or tanks but also the distributed moving targets like river or ocean surfaces. Among the existing GMTI methods, displaced phase center antenna (DPCA) can effectively cancel the strong ground clutter and has been widely used. However, its detection performance is closely related to the target's signal-to-clutter ratio (SCR) as well as radial velocity, and it cannot effectively detect the weak large-sized river surfaces in strong ground clutter due to their low SCR caused by specular scattering. This paper proposes a novel method called relative residue of DPCA (RR-DPCA), which jointly utilizes the DPCA cancellation outputs and the multi-look images to improve the detection performance of weak river surfaces. Furthermore, based on the statistics analysis of the RR-DPCA outputs on the homogenous background, the cell average (CA) method can be well applied for subsequent constant false alarm rate (CFAR) detection. The proposed RR-DPCA method can well detect the point moving targets and distributed moving targets simultaneously. Finally, the results of both simulated and real data are provided to demonstrate the effectiveness of the proposed SAR/GMTI method.

  8. Function-based design process for an intelligent ground vehicle vision system

    Science.gov (United States)

    Nagel, Robert L.; Perry, Kenneth L.; Stone, Robert B.; McAdams, Daniel A.

    2010-10-01

    An engineering design framework for an autonomous ground vehicle vision system is discussed. We present both the conceptual and physical design by following the design process, development and testing of an intelligent ground vehicle vision system constructed for the 2008 Intelligent Ground Vehicle Competition. During conceptual design, the requirements for the vision system are explored via functional and process analysis considering the flows into the vehicle and the transformations of those flows. The conceptual design phase concludes with a vision system design that is modular in both hardware and software and is based on a laser range finder and camera for visual perception. During physical design, prototypes are developed and tested independently, following the modular interfaces identified during conceptual design. Prototype models, once functional, are implemented into the final design. The final vision system design uses a ray-casting algorithm to process camera and laser range finder data and identify potential paths. The ray-casting algorithm is a single thread of the robot's multithreaded application. Other threads control motion, provide feedback, and process sensory data. Once integrated, both hardware and software testing are performed on the robot. We discuss the robot's performance and the lessons learned.

  9. SPARCL: a high-altitude tethered balloon-based optical space-to-ground communication system

    Science.gov (United States)

    Badesha, Surjit S.

    2002-12-01

    The Johns Hopkins University Applied Physics Laboratory (JHU/APL) has conducted a feasibility study to determine if a high altitude (20 km) tethered balloon-based space-to-ground optical communication system is a feasible concept. To support this effort, a detailed concept definition was developed and associated issues were identified and analyzed systematically. Of all the adverse atmospheric phenomena, cloud coverage was identified as the most prohibitive obstacle for a space-to-ground optical communication link. However, by placing a receiver on a balloon at a 20 km altitude, the proposed high altitude system avoids virtually all atmospheric effects. A practical notional scenario was developed (i.e. surveillance and/or reconnaissance of a regional conflict) involving end-to-end optical communication architecture to identify system elements, system level requirements, and to quantify realistic data rate requirements. Analysis of the proposed space-to-ground communication elements indicates that while significant development is required, the system is technically feasible and is a very cost effective 24/7solution.

  10. SAR Ground Moving Target Indication Based on Relative Residue of DPCA Processing

    Directory of Open Access Journals (Sweden)

    Jia Xu

    2016-10-01

    Full Text Available For modern synthetic aperture radar (SAR, it has much more urgent demands on ground moving target indication (GMTI, which includes not only the point moving targets like cars, truck or tanks but also the distributed moving targets like river or ocean surfaces. Among the existing GMTI methods, displaced phase center antenna (DPCA can effectively cancel the strong ground clutter and has been widely used. However, its detection performance is closely related to the target’s signal-to-clutter ratio (SCR as well as radial velocity, and it cannot effectively detect the weak large-sized river surfaces in strong ground clutter due to their low SCR caused by specular scattering. This paper proposes a novel method called relative residue of DPCA (RR-DPCA, which jointly utilizes the DPCA cancellation outputs and the multi-look images to improve the detection performance of weak river surfaces. Furthermore, based on the statistics analysis of the RR-DPCA outputs on the homogenous background, the cell average (CA method can be well applied for subsequent constant false alarm rate (CFAR detection. The proposed RR-DPCA method can well detect the point moving targets and distributed moving targets simultaneously. Finally, the results of both simulated and real data are provided to demonstrate the effectiveness of the proposed SAR/GMTI method.

  11. The effects of thermal aging on material behavior and strength of CF8M in nuclear reactor coolant system

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Jae Do; Lee, Yong Seon; Nam, Uk Hui; Park, Jung Cheol; Pae, Yong Tak; In, Jae Hyeon; Woo, Seung Wan [Yeungnam Univ., Gyeongsan (Korea, Republic of)

    1998-03-15

    The following investigations are performed in order to estimate the mechanism of the thermal integrity, and the life prediction. The CF8M is observed a brittle behavior in the range of 475 .deg. C. The five classes of the thermally aged CF8M specimen are prepared using an artificially accelerated aging method. Namely, after the specimen are held for 100, 300, 900, 1800 and 3600 hrs. at 430 .deg. C respectively, the specimen are water cooled to room temperature. The impact energy variations are measures for both the aged and virgin specimen at -173, -70, -32, 27 and 100 .deg. C respectively through the Charpy impact tests in addition to the hardness tests. The tests results are to be a guide line to predict the life of CF8M, a RCS component material caused by thermal aging. The critical flaw size can be estimated by KIC obtained from the impact energy.

  12. Dust aerosol characterization and transport features based on combined ground-based, satellite and model-simulated data

    Science.gov (United States)

    Vijayakumar, K.; Devara, P. C. S.; Rao, S. Vijaya Bhaskara; Jayasankar, C. K.

    2016-06-01

    In this paper, we study aerosol characteristics over an urban station in Western India, during a dust event that occurred between 19 and 26 March 2012, with the help of ground-based and satellite measurements and model simulation data. The aerosol parameters are found to change significantly during dust events and they suggest dominance of coarse mode aerosols. The fine mode fraction, size distribution and single scattering albedo reveal that dust (natural) aerosols dominate the anthropogenic aerosols over the study region. Ground-based measurements show drastic reduction in visibility on the dust-laden day (22 March 2012). Additionally, HYSPLIT model and satellite daily data have been used to trace the source, path and spatial extent of dust storm events. Most of the dust aerosols, during the study period, travel from west-to-east pathway from source-to-sink region. Furthermore, aerosol vertical profiles from CALIPSO and synoptic meteorological parameters from ECMWF re-analysis data reveal a layer of thick dust extending from surface to an altitude of about 4 km, and decrease in temperature and increase in specific humidity, respectively. The aerosol radiative forcing calculations indicate more cooling at the surface and warming in the atmosphere during dust event. The results of satellite observations are found to have good consistency with ground-based air quality measurements. Synthesis of satellite data integrated with ground-based observations, supplemented by model analysis, is found to be a promising technique for improved understanding of dust storm phenomenon and its impact on regional climate.

  13. Distant activity of 67P/Churyumov-Gerasimenko in 2014: Ground-based results during the Rosetta pre-landing phase

    CERN Document Server

    Snodgrass, Colin; Manfroid, Jean; Opitom, Cyrielle; Fitzsimmons, Alan; Tozzi, Gian Paolo; Faggi, Sara; Yang, Bin; Knight, Matthew M; Conn, Blair C; Lister, Tim; Hainaut, Olivier; Bramich, D M; Lowry, Stephen C; Rozek, Agata; Tubiana, Cecilia; Guilbert-Lepoutre, Aurélie

    2016-01-01

    As the ESA Rosetta mission approached, orbited, and sent a lander to comet 67P/Churyumov-Gerasimenko in 2014, a large campaign of ground-based observations also followed the comet. We constrain the total activity level of the comet by photometry and spectroscopy to place Rosetta results in context and to understand the large-scale structure of the comet's coma pre-perihelion. We performed observations using a number of telescopes, but concentrate on results from the 8m VLT and Gemini South telescopes in Chile. We use R-band imaging to measure the dust coma contribution to the comet's brightness and UV-visible spectroscopy to search for gas emissions, primarily using VLT/FORS. In addition we imaged the comet in near-infrared wavelengths (JHK) in late 2014 with Gemini-S/Flamingos 2. We find that the comet was already active in early 2014 at heliocentric distances beyond 4 au. The evolution of the total activity (measured by dust) followed previous predictions. No gas emissions were detected despite sensitive se...

  14. Kepler and Ground-Based Transits of the exo-Neptune HAT-P-11b

    Science.gov (United States)

    Deming, Drake; Sada, Pedro V.; Jackson, Brian; Peterson, Steven W.; Agol, Eric; Knutson, Heather A.; Jennings, Donald E.; Haase, Plynn; Bays, Kevin

    2011-01-01

    We analyze 26 archival Kepler transits of the exo-Neptune HAT-P-11b, supplemented by ground-based transits observed in the blue (B band) and near-IR (J band). Both the planet and host star are smaller than previously believed; our analysis yields Rp = 4.31 R xor 0.06 R xor and Rs = 0.683 R solar mass 0.009 R solar mass, both about 3 sigma smaller than the discovery values. Our ground-based transit data at wavelengths bracketing the Kepler bandpass serve to check the wavelength dependence of stellar limb darkening, and the J-band transit provides a precise and independent constraint on the transit duration. Both the limb darkening and transit duration from our ground-based data are consistent with the new Kepler values for the system parameters. Our smaller radius for the planet implies that its gaseous envelope can be less extensive than previously believed, being very similar to the H-He envelope of GJ 436b and Kepler-4b. HAT-P-11 is an active star, and signatures of star spot crossings are ubiquitous in the Kepler transit data. We develop and apply a methodology to correct the planetary radius for the presence of both crossed and uncrossed star spots. Star spot crossings are concentrated at phases 0.002 and +0.006. This is consistent with inferences from Rossiter-McLaughlin measurements that the planet transits nearly perpendicular to the stellar equator. We identify the dominant phases of star spot crossings with active latitudes on the star, and infer that the stellar rotational pole is inclined at about 12 deg 5 deg to the plane of the sky. We point out that precise transit measurements over long durations could in principle allow us to construct a stellar Butterfly diagram to probe the cyclic evolution of magnetic activity on this active K-dwarf star.

  15. Automated Planning of Science Products Based on Nadir Overflights and Alerts for Onboard and Ground Processing

    Science.gov (United States)

    Chien, Steve A.; McLaren, David A.; Rabideau, Gregg R.; Mandl, Daniel; Hengemihle, Jerry

    2013-01-01

    A set of automated planning algorithms is the current operations baseline approach for the Intelligent Payload Module (IPM) of the proposed Hyper spectral Infrared Imager (HyspIRI) mission. For this operations concept, there are only local (e.g. non-depletable) operations constraints, such as real-time downlink and onboard memory, and the forward sweeping algorithm is optimal for determining which science products should be generated onboard and on ground based on geographical overflights, science priorities, alerts, requests, and onboard and ground processing constraints. This automated planning approach was developed for the HyspIRI IPM concept. The HyspIRI IPM is proposed to use an X-band Direct Broadcast (DB) capability that would enable data to be delivered to ground stations virtually as it is acquired. However, the HyspIRI VSWIR and TIR instruments will produce approximately 1 Gbps data, while the DB capability is 15 Mbps for a approx. =60X oversubscription. In order to address this mismatch, this innovation determines which data to downlink based on both the type of surface the spacecraft is overflying, and the onboard processing of data to detect events. For example, when the spacecraft is overflying Polar Regions, it might downlink a snow/ice product. Additionally, the onboard software will search for thermal signatures indicative of a volcanic event or wild fire and downlink summary information (extent, spectra) when detected, thereby reducing data volume. The planning system described above automatically generated the IPM mission plan based on requested products, the overflight regions, and available resources.

  16. Estimation of Antarctic ozone loss from Ground-based total column measurements

    Directory of Open Access Journals (Sweden)

    J. Kuttippurath

    2010-03-01

    Full Text Available The passive ozone method is used to estimate ozone loss from ground-based measurements in the Antarctic. A sensitivity study shows that the O3 loss can be estimated within an accuracy of ~4%. The method is then applied to the observations from Amundsen-Scott/South Pole, Arrival Heights, Belgrano, Concordia, Dumont d'Urville, Faraday, Halley, Marambio, Neumayer, Rothera, Syowa and Zhongshan for the diagnosis of ozone loss in the Antarctic. On average, the five-day running mean of the vortex averaged ozone column loss deduced from the ground-based stations shows about 53% in 2009, 59% in 2008, 55% in 2007, 56% in 2006 and 61% in 2005. The observed O3 loss and loss rates are in very good agreement with the satellite observations (Ozone Monitoring Instrument and Sciamachy and are well reproduced by the model (Reprobus and SLIMCAT calculations.

    The historical ground-based total ozone measurements show that the depletion started in the late 1970s, reached a maximum in the early 1990s, stabilising afterwards at this level until present, with the exception of 2002, the year of an early vortex break-up. There is no indication of significant recovery yet.

    At southern mid-latitudes, a total ozone reduction of 40–50% is observed at the newly installed station Rio Gallegos and 25–35% at Kerguelen in October–November of 2008–2009 and 2005–2009 (except 2008 respectively, and of 10–20% at Macquarie Island in July–August of 2006–2009. This illustrates the significance of measurements at the edges of Antarctica.

  17. Ground-Based Network and Supersite Observations to Complement and Enrich EOS Research

    Science.gov (United States)

    Tsay, Si-Chee; Holben, Brent N.; Welton, Ellsworth J.

    2011-01-01

    Since 1997 NASA has been successfully launching a series of satellites - the Earth Observing System (EOS) - to intensively study, and gain a better understanding of, the Earth as an integrated system. Space-borne remote sensing observations, however, are often plagued by contamination of surface signatures. Thus, ground-based in-situ and remote-sensing measurements, where signals come directly from atmospheric constituents, the sun, and/or the Earth-atmosphere interactions, provide additional information content for comparisons that confirm quantitatively the usefulness of the integrated surface, aircraft, and satellite datasets. Through numerous participations, particularly but not limited to the EOS remote-sensing/retrieval and validation projects over the years, NASA/GSFC has developed and continuously refined ground-based networks and mobile observatories that proved to be vital in providing high temporal measurements, which complement and enrich the satellite observations. These are: the AERO NET (AErosol RObotic NETwork) a federation of ground-based globally distributed network of spectral sun-sky photometers; the MPLNET (Micro-Pulse Lidar NETwork, a similarly organized network of micro-pulse lidar systems measuring aerosol and cloud vertical structure continuously; and the SMART-COMMIT (Surface-sensing Measurements for Atmospheric Radiative Transfer - Chemical, Optical & Microphysical Measurements of In-situ Troposphere, mobile observatories, a suite of spectral radiometers and in-situ probes acquiring supersite measurements. Most MPLNET sites are collocated with those of AERONET, and both networks always support the deployment of SMART-COMMIT worldwide. These data products follow the data structure of EOS conventions: Level-0, instrument archived raw data; Level-1 (or 1.5), real-time data with no (or limited) quality assurance; Level-2, not real high temporal and spectral resolutions. In this talk, we will present NASA/GSFC groundbased facilities, serving

  18. Ground-based SMART-COMMIT Measurements for Studying Aerosol and Cloud Properties

    Science.gov (United States)

    Tsay, Si-Chee

    2008-01-01

    From radiometric principles, it is expected that the retrieved properties of extensive aerosols and clouds from reflected/emitted measurements by satellite (and/or aircraft) should be consistent with those retrieved from transmitted/emitted radiance observed at the surface. Although space-borne remote sensing observations cover large spatial domain, they are often plagued by contamination of surface signatures. Thus, ground-based in-situ and remote-sensing measurements, where signals come directly from atmospheric constituents, the sun, and/or the Earth-atmosphere interactions, provide additional information content for comparisons that confirm quantitatively the usefulness of the integrated surface, aircraft, and satellite data sets. The development and deployment of SMARTCOMMIT (Surface-sensing Measurements for Atmospheric Radiative Transfer - Chemical, Optical & Microphysical Measurements of In-situ Troposphere) mobile facilities are aimed for the optimal utilization of collocated ground-based observations as constraints to yield higher fidelity satellite retrievals and to determine any sampling bias due to target conditions. To quantify the energetics of the surface-atmosphere system and the atmospheric processes, SMART-COMMIT instruments fall into three categories: flux radiometer, radiance sensor and in-situ probe. In this paper, we will demonstrate the capability of SMART-COMMIT in recent field campaigns (e.g., CRYSTAL-FACE, UAE 2, BASEASIA, NAMMA) that were designed and executed to study the compelling variability in temporal scale of both anthropogenic and natural aerosols (e.g., biomass-burning smoke, airborne dust) and cirrus clouds. We envision robust approaches in which well-collocated ground-based measurements and space-borne observations will greatly advance our knowledge of extensive aerosols and clouds.

  19. Mesospheric minor species determinations from rocket and ground-based i.r. measurements

    Science.gov (United States)

    Ulwick, J. C.; Baker, K. D.; Baker, D. J.; Steed, A. J.; Pendleton, W. R.; Grossmann, K.; Brückelmann, H. G.

    As part of the MAP/WINE campaign the infrared hydroxyl airglow layer was investigated at Kiruna, Sweden, by simultaneous measurements with rocket probes of OH ≠ and O2( a1Δg) infrared emissions and concentrations of odd oxygen species (O and O 3). Coordinated measurements of OH ≠ and O2( a1Δg) zenith radiance and emission spectra and their time histories were made from the ground. The rocket-borne Λ = 1.55 μm radiometer ( ΔΛ ≊ 0.23 μm) provided volume emission rates for OH for both rocket ascent and descent, showing a peak near 87 km with a maximum of nearly 10 6 photons sec -1 cm -3. The atomic oxygen distribution showed a concentration of about 10 11 cm -3 between 88 and 100 km, dropping off sharply below 85 km. The ground-based radiometer at Λ = 1.56 μm, which had a similar filter bandpass to the rocket-borne instrument, yielded an equivalent of 130 kR for the total OH Δv = 2 sequence, which is consistent with the zenith-corrected rocket-based sequence radiance value of ≌ 110 kR. The rotational temperature of the OH night airglow obtained from the rotational structure of the OH M (3,1) band observed by the ground-based interferometer was about 195K at the time of the rocket measurement. Atomic oxygen concentrations were calculated from the OH profile and show agreement with the directly measured values. Atomic hydrogen concentrations of a few times 10 7 cm -3 near 85 km were inferred from the data set.

  20. Regional estimation of base recharge to ground water using water balance and a base-flow index.

    Science.gov (United States)

    Szilagyi, Jozsef; Harvey, F Edwin; Ayers, Jerry F

    2003-01-01

    Naturally occurring long-term mean annual base recharge to ground water in Nebraska was estimated with the help of a water-balance approach and an objective automated technique for base-flow separation involving minimal parameter-optimization requirements. Base recharge is equal to total recharge minus the amount of evapotranspiration coming directly from ground water. The estimation of evapotranspiration in the water-balance equation avoids the need to specify a contributing drainage area for ground water, which in certain cases may be considerably different from the drainage area for surface runoff. Evapotranspiration was calculated by the WREVAP model at the Solar and Meteorological Surface Observation Network (SAMSON) sites. Long-term mean annual base recharge was derived by determining the product of estimated long-term mean annual runoff (the difference between precipitation and evapotranspiration) and the base-flow index (BFI). The BFI was calculated from discharge data obtained from the U.S. Geological Survey's gauging stations in Nebraska. Mapping was achieved by using geographic information systems (GIS) and geostatistics. This approach is best suited for regional-scale applications. It does not require complex hydrogeologic modeling nor detailed knowledge of soil characteristics, vegetation cover, or land-use practices. Long-term mean annual base recharge rates in excess of 110 mm/year resulted in the extreme eastern part of Nebraska. The western portion of the state expressed rates of only 15 to 20 mm annually, while the Sandhills region of north-central Nebraska was estimated to receive twice as much base recharge (40 to 50 mm/year) as areas south of it.

  1. Ground-based measurements of aerosol optical properties and radiative forcing in North China

    Institute of Scientific and Technical Information of China (English)

    Hongbin Chen; Xiangao Xia; Pucai Wang; Wenxing Zhang

    2007-01-01

    In order to gain an insight into the aerosol properties and their climatic effect over the continental source regions of China, it is of significance to carry out long-term ground-based measurements of aerosol optical properties and radiative forcing. A couple of temporary and permanent Aerosol Robotic Network (AERONET) sites and three comprehensive radiative sites were established in China as a result of international cooperation in recent years. Heavy aerosol loading and significant temporal and spatial variation over North China are revealed by the AERONET data.Aerosol-induced reductions in surface radiation budget are examined on the basis of collocated observations by sun photometers and pyranometers.

  2. Synergetic ground-based methods for remote measurements of ozone vertical profiles

    Science.gov (United States)

    Timofeyev, Yuriy; Kostsov, Vladimir; Virolainen, Yana

    2013-05-01

    The technique of combining ground-based measurements in infrared and microwave spectral regions in order to achieve higher accuracy of ozone profile retrieval in extensive altitude ranges is described and analyzed. The information content, errors, altitude ranges and vertical resolution of ozone profile retrieval have been studied on the basis of numerical simulation of synergetic experiments. Optimal conditions of measurements are defined and requirements to additional information are formulated. The first results on ozone vertical profile retrieval using groundbased measurements of FTIR-spectrometer and microwave radiometer are given.

  3. Solar diameter, eclipses and transits: the importance of ground-based observations

    CERN Document Server

    Sigismondi, Costantino

    2012-01-01

    According to satellite measurements the difference between polar and equatorial radius does not exceed 10 milliarcsec. These measurements are differential, and the absolute value of the solar diameter is not precisely known to a level of accuracy needed for finding variations during years or decades. Moreover the lifetime of a satellite is limited, and its calibration is not stable. This shows the need to continue ground-based observations of the Sun exploiting in particular the methods less affected by atmospheric turbulence, as the planetary transits and the total and annular eclipses. The state of art, the advantages and the limits of these two methods are here considered.

  4. Asteroseismology of Solar-type stars with Kepler III. Ground-based Data

    CERN Document Server

    Molenda-Zakowicz, Joanna; Sousa, Sergio; Frasca, Antonio; Biazzo, Katia; Huber, Daniel; Ireland, Mike; Bedding, Tim; Stello, Dennis; Uytterhoeven, Katrien; Dreizler, Stefan; De Cat, Peter; Briquet, Maryline; Catanzaro, Giovanni; Karoff, Chistoffer; Frandsen, Soeren; Spezzi, Loredana; Catala, Claude

    2010-01-01

    We report on the ground-based follow-up program of spectroscopic and photometric observations of solar-like asteroseismic targets for the Kepler space mission. These stars constitute a large group of more than thousand objects which are the subject of an intensive study of the Kepler Asteroseismic Science Consortium Working Group 1 (KASC WG-1). The main goal of this coordinated research is the determination of the fundamental stellar atmospheric parameters, which are used for the computing of their asteroseismic models, as well as for the verification of the Kepler Input Catalogue (KIC).

  5. Integrated interpretation of helicopter and ground-based geophysical data recorded within the Okavango Delta, Botswana

    DEFF Research Database (Denmark)

    Podgorski, Joel E.; Green, Alan G.; Kalscheuer, Thomas

    2015-01-01

    ) data recorded across most of the delta, (ii) 2D models and images derived from ground-based electrical resistance tomographic, transient electromagnetic, and high resolution seismic reflection/refraction tomographic data acquired at four selected sites in western and north-central regions of the delta...... resistivities and very low to low P-wave velocities. Except for images of several buried abandoned river channels, it is non-reflective. The laterally extensive underlying unit of low resistivities, low P-wave velocity, and subhorizontal reflectors very likely contains saline-water-saturated sands and clays...... reflectivity. The interface between the POM unit and basement is a prominent seismic reflector....

  6. Hypergravity Facilities in the ESA Ground-Based Facility Program - Current Research Activities and Future Tasks

    Science.gov (United States)

    Frett, Timo; Petrat, Guido; W. A. van Loon, Jack J.; Hemmersbach, Ruth; Anken, Ralf

    2016-06-01

    Research on Artificial Gravity (AG) created by linear acceleration or centrifugation has a long history and could significantly contribute to realize long-term human spaceflight in the future. Employing centrifuges plays a prominent role in human physiology and gravitational biology. This article gives a short review about the background of Artificial Gravity with respect to hypergravity (including partial gravity) and provides information about actual ESA ground-based facilities for research on a variety of biosystems such as cells, plants, animals or, particularly, humans.

  7. Images of Neptune's ring arcs obtained by a ground-based telescope

    Science.gov (United States)

    Sicardy, B.; Roddier, F.; Roddier, C.; Perozzi, E.; Graves, J. E.; Guyon, O.; Northcott, M. J.

    1999-08-01

    Neptune has a collection of incomplete narrow rings, known as ring arcs, which should in isolation be destroyed by differential motion in a matter of months. Yet since first discovered by stellar occultations in 1984, they appear to have persisted, perhaps through a gravitational resonance effect involving the satellite Galatea. Here we report ground-based observations of the ring arcs, obtained using an adaptive optics system. Our data, and those obtained using the Hubble Space Telescope (reported in a companion paper), indicate that the ring arcs are near, but not within the resonance with Galatea, in contrast to what is predicted by some models.

  8. SCENARIO AND TARGET SIMULATION FOR A GROUND BASED MULTIFUNCTION PHASED ARRAY RADAR

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    This paper describes a scenario and target simulation which operates in non real-time to provide full closed-loop operation of the ground based multifunction phased array radar simulation system in support of ballistic missile defence experiments against countermeasure.By simulating the target scattering signature and dynamical signature,this scenario and target simulation provide re- alistic scenario source to evaluate the system performance of multifunction phased array radar,and the key algorithms verification and validation such as target tracking,multi-target imaging and target recognition.

  9. Low velocity target detection based on time-frequency image for high frequency ground wave radar

    Institute of Scientific and Technical Information of China (English)

    YAN Songhua; WU Shicai; WEN Biyang

    2007-01-01

    The Doppler spectral broadening resulted from non-stationary movement of target and radio-frequency interference will decrease the veracity of target detection by high frequency ground wave(HEGW)radar.By displaying the change of signal energy on two dimensional time-frequency images based on time-frequency analysis,a new mathematical morphology method to distinguish target from nonlinear time-frequency curves is presented.The analyzed results from the measured data verify that with this new method the target can be detected correctly from wide Doppler spectrum.

  10. A Rule-Based Local Search Algorithm for General Shift Design Problems in Airport Ground Handling

    DEFF Research Database (Denmark)

    Clausen, Tommy

    We consider a generalized version of the shift design problem where shifts are created to cover a multiskilled demand and fit the parameters of the workforce. We present a collection of constraints and objectives for the generalized shift design problem. A local search solution framework with mul...... with multiple neighborhoods and a loosely coupled rule engine based on simulated annealing is presented. Computational experiments on real-life data from various airport ground handling organization show the performance and flexibility of the proposed algorithm....

  11. Improved ground-based FTS measurement for column abundance CO2 retrievals(Conference Presentation)

    Science.gov (United States)

    Goo, Tae-Young

    2016-10-01

    The National Institute of Meteorological Sciences has operated a ground-based Fourier Transform Spectrometer (FTS) at Anmyeondo, Korea since December 2012. Anmyeondo FTS site is a designated operational station of Total Carbon Column Observing Network (TCCON) and belongs to regional Global Atmosphere Watch observatory. A Bruker IFS-125HR model, which has a significantly high spectral resolution by 0.02 cm-1, is employed and instrument specification is almost same as the TCCON configuration. such as a spectrum range of 3,800 16,000 cm-1, a resolution of 1 cm-1, InGaAs and Si-Diode detectors and CaF2 beam splitter. It is found that measured spectra have a good agreement with simulated spectra. In order to improve the spectral accuracy and stability, The Operational Automatic System for Intensity of Sunray (OASIS) has been developed. The OASIS can provide consistent photon energy optimized to detector range by controlling the diameter of solar beam reflected from the mirror of suntracker. As a result, monthly modulation efficiency (ME), which indicates the spectral accuracy of FTS measurement, has been recorded the vicinity of 99.9% since Feb 2015. The ME of 98% is regarded as the error of 0.1% in the ground-based in-situ CO2 measurement. Total column abundances of CO2 and CH4 during 2015 are estimated by using GGG v14 and compared with ground-based in-situ CO2 and CH4 measurements at the height of 86 m above sea level. The seasonality of CO2 is well captured by both FTS and in-situ measurements while there is considerable difference on the amplitude of CO2 seasonal variation due to the insensitivity of column CO2 to the surface carbon cycle dynamics in nature as well as anthropogenic sources. Total column CO2 and CH4 approximately vary from 395 ppm to 405 ppm and from 1.82 ppm to 1.88 ppm, respectively. It should be noted that few measurements obtained in July to August because of a lot of cloud and fog. It is found that enhancement of CH4 from the FTS at Anmyeondo

  12. Height Compensation Using Ground Inclination Estimation in Inertial Sensor-Based Pedestrian Navigation

    Directory of Open Access Journals (Sweden)

    Sang Kyeong Park

    2011-08-01

    Full Text Available In an inertial sensor-based pedestrian navigation system, the position is estimated by double integrating external acceleration. A new algorithm is proposed to reduce z axis position (height error. When a foot is on the ground, a foot angle is estimated using accelerometer output. Using a foot angle, the inclination angle of a road is estimated. Using this road inclination angle, height difference of one walking step is estimated and this estimation is used to reduce height error. Through walking experiments on roads with different inclination angles, the usefulness of the proposed algorithm is verified.

  13. Planet Sensitivity from Combined Ground- and Space-based Microlensing Observations

    CERN Document Server

    Zhu, Wei; Beichman, Charles; Novati, Sebastiano Calchi; Carey, Sean; Gaudi, B Scott; Henderson, Calen B; Penny, Matthew; Shvartzvald, Yossi; Yee, Jennifer C; Udalski, A; Poleski, R; Skowron, J; Kozlowski, S; Mroz, P; Pietrukowicz, P; Pietrzynski, G; Szymanski, M K; Soszynski, I; Ulaczyk, K; Wyrzykowski, L; Abe, F; Barry, R K; Bennett, D P; Bhattacharya, A; Fukunaga, D; Inayama, K; Koshimoto, N; Namba, S; Sumi, T; Suzuki, D; Tristram, P J; Wakiyama, Y; Yonehara, A; Maoz, D; Kaspi, S; Friedmann, M

    2015-01-01

    To move one step forward toward a Galactic distribution of planets, we present the first planet sensitivity analysis for microlensing events with simultaneous observations from space and the ground. We present this analysis for two such events, OGLE-2014-BLG-0939 and OGLE-2014-BLG-0124, which both show substantial planet sensitivity even though neither of them reached high magnification. This suggests that an ensemble of low to moderate magnification events can also yield significant planet sensitivity and therefore probability to detect planets. The implications of our results to the ongoing and future space-based microlensing experiments to measure the Galactic distribution of planets are discussed.

  14. Ground-Based Gas-Liquid Flow Research in Microgravity Conditions: State of Knowledge

    Science.gov (United States)

    McQuillen, J.; Colin, C.; Fabre, J.

    1999-01-01

    During the last decade, ground-based microgravity facilities have been utilized in order to obtain predictions for spacecraft system designers and further the fundamental understanding of two-phase flow. Although flow regime, pressure drop and heat transfer coefficient data has been obtained for straight tubes and a limited number of fittings, measurements of the void fraction, film thickness, wall shear stress, local velocity and void information are also required in order to develop general mechanistic models that can be utilized to ascertain the effects of fluid properties, tube geometry and acceleration levels. A review of this research is presented and includes both empirical data and mechanistic models of the flow behavior.

  15. Ground-based and spaceborn observations of the type II burst with developed fine structure

    Science.gov (United States)

    Dorovskyy, V.; Melnik, V.; Konovalenko, A.; Brazhenko, A.; Rucker, H.; Stanislavskyy, A.; Panchenko, M.

    2012-09-01

    The combination of two huge ground-based radio telescopes (UTR-2 and URAN-2) operated in decameter wavelengths with three spatially separated spacecrafts (SOHO, STEREO-A and STEREO-B) equipped with white light coronagraphs, UV telescopes and decameter-hectometer band radio telescopes created a unique opportunity to investigate the high energy solar transients, such as CMEs and their manifestations in radio bands - type II bursts. In this paper we made detailed analysis of the powerful and complex event occurred on 7 June 2011 consisted of Halo-CME and type II burst with rich fine structure.

  16. Ground-based follow-up in relation to Kepler asteroseismic investigation

    Science.gov (United States)

    Uytterhoeven, K.; Briquet, M.; Bruntt, H.; De Cat, P.; Frandsen, S.; Gutiérrez-Soto, J.; Kiss, L.; Kurtz, D. W.; Marconi, M.; Molenda-Żakowicz, J.; Østensen, R.; Randall, S.; Southworth, J.; Szabó, R.

    2010-12-01

    The Kepler space mission, successfully launched in March 2009, is providing continuous and high-precision photometry of thousands of stars simultaneously. The uninterrupted time-series of stars of all known pulsation types are a precious source for asteroseismic studies. The Kepler data do not provide information on the physical parameters, such as T_eff, log g, metallicity, and v sin i, which are crucial for successful asteroseismic modelling. Additional ground-based time-series data are needed to characterize mode parameters in several types of pulsating stars. Therefore, ground-based multi-colour photometry and mid/high-resolution spectroscopy are needed to complement the space data. We present ground-based activities within KASC on selected asteroseismic Kepler targets of several pulsation types. Based on observations made with the Isaac Newton Telescope and William Herschel Telescope operated by the Isaac Newton Group, with the Nordic Optical Telescope, operated jointly by Denmark, Finland, Iceland, Norway, and Sweden, with the Italian Telescopio Nazionale Galileo (TNG) operated by the Fundación Galileo Galilei of the INAF (Istituto Nazionale di Astrofisica), and with the Mercator telescope, operated by the Flemish Community, all on the island of La Palma at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias (IAC). Based on observations made with the IAC-80 operated on the island of Tenerife by the IAC at the Spanish Observatorio del Teide. Also based on observations taken at the observatories of Sierra Nevada, San Pedro Mártir, Vienna, Xinglong, Apache Point, Lulin, Tautenburg, McDonald, Skinakas, Pic du Midi, Mauna Kea, Steward Observatory, Mt. Wilson, Białków Observatory of the Wrocław University, Piszkésteto Mountain Station, and Observatoire de Haute Provence. Based on spectra taken at the Loiano (INAF - OA Bologna), Serra La Nave (INAF - OA Catania) and Asiago (INAF - OA Padova) observatories. Also

  17. Ground-based Observations of the Solar Sources of Space Weather (Invited Review)

    CERN Document Server

    Veronig, Astrid M

    2016-01-01

    Monitoring of the Sun and its activity is a task of growing importance in the frame of space weather research and awareness. Major space weather disturbances at Earth have their origin in energetic outbursts from the Sun: solar flares, coronal mass ejections and associated solar energetic particles. In this review we discuss the importance and complementarity of ground-based and space-based observations for space weather studies. The main focus is drawn on ground-based observations in the visible range of the spectrum, in particular in the diagnostically manifold H$\\alpha$ spectral line, which enables us to detect and study solar flares, filaments, filament eruptions, and Moreton waves. Existing H$\\alpha$ networks such as the GONG and the Global High-Resolution H$\\alpha$ Network are discussed. As an example of solar observations from space weather research to operations, we present the system of real-time detection of H$\\alpha$ flares and filaments established at Kanzelh\\"ohe Observatory (KSO; Austria) in the...

  18. Phantom-based ground-truth generation for cerebral vessel segmentation and pulsatile deformation analysis

    Science.gov (United States)

    Schetelig, Daniel; Säring, Dennis; Illies, Till; Sedlacik, Jan; Kording, Fabian; Werner, René

    2016-03-01

    Hemodynamic and mechanical factors of the vascular system are assumed to play a major role in understanding, e.g., initiation, growth and rupture of cerebral aneurysms. Among those factors, cardiac cycle-related pulsatile motion and deformation of cerebral vessels currently attract much interest. However, imaging of those effects requires high spatial and temporal resolution and remains challenging { and similarly does the analysis of the acquired images: Flow velocity changes and contrast media inflow cause vessel intensity variations in related temporally resolved computed tomography and magnetic resonance angiography data over the cardiac cycle and impede application of intensity threshold-based segmentation and subsequent motion analysis. In this work, a flow phantom for generation of ground-truth images for evaluation of appropriate segmentation and motion analysis algorithms is developed. The acquired ground-truth data is used to illustrate the interplay between intensity fluctuations and (erroneous) motion quantification by standard threshold-based segmentation, and an adaptive threshold-based segmentation approach is proposed that alleviates respective issues. The results of the phantom study are further demonstrated to be transferable to patient data.

  19. Modelling systematics of ground-based transit photometry I. Implications on transit timing variations

    CERN Document Server

    von Essen, C; Mallonn, M; Tingley, B; Marcussen, M

    2016-01-01

    The transit timing variation technique (TTV) has been widely used to detect and characterize multiple planetary systems. Due to the observational biases imposed mainly by the photometric conditions and instrumentation and the high signal-to-noise required to produce primary transit observations, ground-based data acquired using small telescopes limit the technique to the follow-up of hot Jupiters. However, space-based missions such as Kepler and CoRoT have already revealed that hot Jupiters are mainly found in single systems. Thus, it is natural to question ourselves if we are properly using the observing time at hand carrying out such follow-ups, or if the use of medium-to-low quality transit light curves, combined with current standard techniques of data analysis, could be playing a main role against exoplanetary search via TTVs. The purpose of this work is to investigate to what extent ground-based observations treated with current modelling techniques are reliable to detect and characterize additional pla...

  20. a Universal De-Noising Algorithm for Ground-Based LIDAR Signal

    Science.gov (United States)

    Ma, Xin; Xiang, Chengzhi; Gong, Wei

    2016-06-01

    Ground-based lidar, working as an effective remote sensing tool, plays an irreplaceable role in the study of atmosphere, since it has the ability to provide the atmospheric vertical profile. However, the appearance of noise in a lidar signal is unavoidable, which leads to difficulties and complexities when searching for more information. Every de-noising method has its own characteristic but with a certain limitation, since the lidar signal will vary with the atmosphere changes. In this paper, a universal de-noising algorithm is proposed to enhance the SNR of a ground-based lidar signal, which is based on signal segmentation and reconstruction. The signal segmentation serving as the keystone of the algorithm, segments the lidar signal into three different parts, which are processed by different de-noising method according to their own characteristics. The signal reconstruction is a relatively simple procedure that is to splice the signal sections end to end. Finally, a series of simulation signal tests and real dual field-of-view lidar signal shows the feasibility of the universal de-noising algorithm.

  1. Ground-based and spacecraft observations of lightning activity on Saturn

    Science.gov (United States)

    Zakharenko, V.; Mylostna, C.; Konovalenko, A.; Zarka, P.; Fischer, G.; Grießmeier, J.-M.; Litvinenko, G.; Rucker, H.; Sidorchuk, M.; Ryabov, B.; Vavriv, D.; Ryabov, V.; Cecconi, B.; Coffre, A.; Denis, L.; Fabrice, C.; Pallier, L.; Schneider, J.; Kozhyn, R.; Vinogradov, V.; Mukha, D.; Weber, R.; Shevchenko, V.; Nikolaenko, V.

    2012-02-01

    In late 2007, Saturn electrostatic discharges (SED) were simultaneously observed at the radio telescope UTR-2 and with the Cassini spacecraft. Observations at UTR-2 were performed with a multichannel receiver in the frequency range 12-33 MHz, and those performed on Cassini-with a swept frequency receiver that is part of the RPWS (Radio and Plasma Wave Science) instrument in the frequency band 1.8-16 MHz. We got a very good coincidence between data of UTR-2 and Cassini. It is shown for the first time that ground-based radio astronomy lets us detect Saturn's lightning with a high degree of reliability despite terrestrial interferences. This is the necessary basis for further detailed study of the temporal and spectral characteristics of the SEDs with ground based radio telescopes. Based on six observation sessions, several parameters of SEDs were determined, in particularly a correlation of 0.77±0.15 between the average intensity of storms and the e-folding time.

  2. Raster-based regolith thickness of the Lost Creek Designated Ground Water Basin, Weld, Adams, and Arapahoe Counties, Colorado

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This dataset consists of raster-based generalized thickness of regolith (unconsolidated sediments) overlying bedrock in the Lost Creek Designated Ground Water Basin,...

  3. Exploring the relationship between monitored ground-based and satellite aerosol measurements over the City of Johannesburg

    CSIR Research Space (South Africa)

    Garland, Rebecca M

    2012-09-01

    Full Text Available This project studied the relationship between aerosol optical depth (AOD) from the Multi-angle Imaging SpectroRadiometer (MISR) instrument on the Terra satellite, and ground-based monitored particulate matter (PM) mass concentrations measured...

  4. Development of Neural Network Model for Predicting Peak Ground Acceleration Based on Microtremor Measurement and Soil Boring Test Data

    National Research Council Canada - National Science Library

    Kerh, T; Lin, J. S; Gunaratnam, D

    2012-01-01

    .... This paper is therefore aimed at developing a neural network model, based on available microtremor measurement and on-site soil boring test data, for predicting peak ground acceleration at a site...

  5. Integrated water vapor from IGS ground-based GPS observations. Initial results from a global 5-min data set

    Energy Technology Data Exchange (ETDEWEB)

    Heise, S.; Dick, G.; Gendt, G.; Schmidt, T.; Wickert, J. [GFZ German Research Centre for Geosciences, Potsdam (Germany). Dept. 1 Geodesy and Remote Sensing

    2009-07-01

    Ground based GPS zenith path delay (ZPD) measurements are well established as a powerful tool for integrated water vapor (IWV) observation. The International GNSS Service (IGS) provides ZPD data of currently more than 300 globally distributed GPS stations. To derive IWV from these data, meteorological information (ground pressure and mean temperature above the station) are needed. Only a limited number of IGS stations is equipped with meteorological ground sensors up to now. Thus, meteorological data for IWV conversion are usually derived from nearby ground meteorological observations (ground pressure) and meteorological analyses (mean temperature). In this paper we demonstrate for the first time the applicability of ground pressure data from ECMWF meteorological analysis fields in this context. Beside simplified data handling (no single station data and quality control) this approach allows for IWV derivation if nearby meteorological stations are not available. Using ECMWF ground pressure and mean temperature data the new IGS 5-min ZPD data set has been converted to IWV for the first time. We present initial results from selected stations with ground meteorological sensors including pressure and temperature comparisons between ECMWF and local measurements. The GPS IWV is generally validated by comparison with ECMWF IWV. The ECMWF derived station meteorological data are compared with local measurements at all accordingly equipped stations. Based on this comparison, the mean error (in terms of standard deviation) introduced by time interpolation of the 6-hourly ECMWF data is estimated below 0.2 mm IWV. (orig.)

  6. Human Walking Pattern Recognition Based on KPCA and SVM with Ground Reflex Pressure Signal

    Directory of Open Access Journals (Sweden)

    Zhaoqin Peng

    2013-01-01

    Full Text Available Algorithms based on the ground reflex pressure (GRF signal obtained from a pair of sensing shoes for human walking pattern recognition were investigated. The dimensionality reduction algorithms based on principal component analysis (PCA and kernel principal component analysis (KPCA for walking pattern data compression were studied in order to obtain higher recognition speed. Classifiers based on support vector machine (SVM, SVM-PCA, and SVM-KPCA were designed, and the classification performances of these three kinds of algorithms were compared using data collected from a person who was wearing the sensing shoes. Experimental results showed that the algorithm fusing SVM and KPCA had better recognition performance than the other two methods. Experimental outcomes also confirmed that the sensing shoes developed in this paper can be employed for automatically recognizing human walking pattern in unlimited environments which demonstrated the potential application in the control of exoskeleton robots.

  7. Ground penetrating detection using miniaturized radar system based on solid state microwave sensor.

    Science.gov (United States)

    Yao, B M; Fu, L; Chen, X S; Lu, W; Guo, H; Gui, Y S; Hu, C-M

    2013-12-01

    We propose a solid-state-sensor-based miniaturized microwave radar technique, which allows a rapid microwave phase detection for continuous wave operation using a lock-in amplifier rather than using expensive and complicated instruments such as vector network analyzers. To demonstrate the capability of this sensor-based imaging technique, the miniaturized system has been used to detect embedded targets in sand by measuring the reflection for broadband microwaves. Using the reconstruction algorithm, the imaging of the embedded target with a diameter less than 5 cm buried in the sands with a depth of 5 cm or greater is clearly detected. Therefore, the sensor-based approach emerges as an innovative and cost-effective way for ground penetrating detection.

  8. Magnitude Estimation for the 2011 Tohoku-Oki Earthquake Based on Ground Motion Prediction Equations

    Science.gov (United States)

    Eshaghi, Attieh; Tiampo, Kristy F.; Ghofrani, Hadi; Atkinson, Gail M.

    2015-08-01

    This study investigates whether real-time strong ground motion data from seismic stations could have been used to provide an accurate estimate of the magnitude of the 2011 Tohoku-Oki earthquake in Japan. Ultimately, such an estimate could be used as input data for a tsunami forecast and would lead to more robust earthquake and tsunami early warning. We collected the strong motion accelerograms recorded by borehole and free-field (surface) Kiban Kyoshin network stations that registered this mega-thrust earthquake in order to perform an off-line test to estimate the magnitude based on ground motion prediction equations (GMPEs). GMPEs for peak ground acceleration and peak ground velocity (PGV) from a previous study by Eshaghi et al. in the Bulletin of the Seismological Society of America 103. (2013) derived using events with moment magnitude ( M) ≥ 5.0, 1998-2010, were used to estimate the magnitude of this event. We developed new GMPEs using a more complete database (1998-2011), which added only 1 year but approximately twice as much data to the initial catalog (including important large events), to improve the determination of attenuation parameters and magnitude scaling. These new GMPEs were used to estimate the magnitude of the Tohoku-Oki event. The estimates obtained were compared with real time magnitude estimates provided by the existing earthquake early warning system in Japan. Unlike the current operational magnitude estimation methods, our method did not saturate and can provide robust estimates of moment magnitude within ~100 s after earthquake onset for both catalogs. It was found that correcting for average shear-wave velocity in the uppermost 30 m () improved the accuracy of magnitude estimates from surface recordings, particularly for magnitude estimates of PGV (Mpgv). The new GMPEs also were used to estimate the magnitude of all earthquakes in the new catalog with at least 20 records. Results show that the magnitude estimate from PGV values using

  9. Geocenter variations derived from a combined processing of LEO- and ground-based GPS observations

    Science.gov (United States)

    Männel, Benjamin; Rothacher, Markus

    2017-08-01

    GNSS observations provided by the global tracking network of the International GNSS Service (IGS, Dow et al. in J Geod 83(3):191-198, 2009) play an important role in the realization of a unique terrestrial reference frame that is accurate enough to allow a detailed monitoring of the Earth's system. Combining these ground-based data with GPS observations tracked by high-quality dual-frequency receivers on-board low earth orbiters (LEOs) is a promising way to further improve the realization of the terrestrial reference frame and the estimation of geocenter coordinates, GPS satellite orbits and Earth rotation parameters. To assess the scope of the improvement on the geocenter coordinates, we processed a network of 53 globally distributed and stable IGS stations together with four LEOs (GRACE-A, GRACE-B, OSTM/Jason-2 and GOCE) over a time interval of 3 years (2010-2012). To ensure fully consistent solutions, the zero-difference phase observations of the ground stations and LEOs were processed in a common least-squares adjustment, estimating all the relevant parameters such as GPS and LEO orbits, station coordinates, Earth rotation parameters and geocenter motion. We present the significant impact of the individual LEO and a combination of all four LEOs on the geocenter coordinates. The formal errors are reduced by around 20% due to the inclusion of one LEO into the ground-only solution, while in a solution with four LEOs LEO-specific characteristics are significantly reduced. We compare the derived geocenter coordinates w.r.t. LAGEOS results and external solutions based on GPS and SLR data. We found good agreement in the amplitudes of all components; however, the phases in x- and z-direction do not agree well.

  10. A Process Model for Deployment Planning of Ground-based Air Defense System Against Asymmetric Homeland Threat

    Science.gov (United States)

    2009-01-01

    A Process Model for Deployment Planning of Ground-based Air Defense System Against Asymmetric Homeland Threat Ronald L. Cypert Scientific...units, along with coordination at the state and federal agency level, a dynamic process modeling capability was chosen to chart the myriad...COVERED 00-00-2009 to 00-00-2009 4. TITLE AND SUBTITLE A Process Model for Deployment Planning of Ground-based Air Defense System Against

  11. 8-mJ TEM(00) diode-end-pumped frequency-quadrupled Nd:YAG laser.

    Science.gov (United States)

    Feugnet, G; Pocholle, J P

    1998-01-01

    A frequency-quadrupled Nd:YAG laser pumped by a commercially available high-brightness stack is described. A master oscillator power amplifier configuration was implanted, and the laser delivered energy of 8 mJ at 0.266microm . The laser was air cooled for easy use.

  12. Asteroseismology with the WIRE satellite. I. Combining Ground- and Space-based Photometry of the Delta Scuti Star Epsilon Cephei

    CERN Document Server

    Bruntt, H; Bedding, T R; Buzasi, D L; Moya, A; Amado, P J; Martin-Ruiz, S; Garrido, R; De Coca, P L; Rolland, A; Costa, V; Olivares, I; Garcia-Pelayo, J M

    2006-01-01

    We have analysed ground-based multi-colour Stromgren photometry and single-filter photometry from the star tracker on the WIRE satellite of the delta scuti star Epsilon Cephei. The ground-based data set consists of 16 nights of data collected over 164 days, while the satellite data are nearly continuous coverage of the star during 14 days. The spectral window and noise level of the satellite data are superior to the ground-based data and this data set is used to locate the frequencies. However, we can use the ground-based data to improve the accuracy of the frequencies due to the much longer time baseline. We detect 26 oscillation frequencies in the WIRE data set, but only some of these can be seen clearly in the ground-based data. We have used the multi-colour ground-based photometry to determine amplitude and phase differences in the Stromgren b-y colour and the y filter in an attempt to identify the radial degree of the oscillation frequencies. We conclude that the accuracies of the amplitudes and phases a...

  13. Development of a Ground-Based Atmospheric Monitoring Network for the Global Mercury Observation System (GMOS

    Directory of Open Access Journals (Sweden)

    Sprovieri F.

    2013-04-01

    Full Text Available Consistent, high-quality measurements of atmospheric mercury (Hg are necessary in order to better understand Hg emissions, transport, and deposition on a global scale. Although the number of atmospheric Hg monitoring stations has increased in recent years, the available measurement database is limited and there are many regions of the world where measurements have not been extensively performed. Long-term atmospheric Hg monitoring and additional ground-based monitoring sites are needed in order to generate datasets that will offer new insight and information about the global scale trends of atmospheric Hg emissions and deposition. In the framework of the Global Mercury Observation System (GMOS project, a coordinated global observational network for atmospheric Hg is being established. The overall research strategy of GMOS is to develop a state-of-the-art observation system able to provide information on the concentration of Hg species in ambient air and precipitation on the global scale. This network is being developed by integrating previously established ground-based atmospheric Hg monitoring stations with newly established GMOS sites that are located both at high altitude and sea level locations, as well as in climatically diverse regions. Through the collection of consistent, high-quality atmospheric Hg measurement data, we seek to create a comprehensive assessment of atmospheric Hg concentrations and their dependence on meteorology, long-range atmospheric transport and atmospheric emissions.

  14. Potential use of ground-based sensor technologies for weed detection.

    Science.gov (United States)

    Peteinatos, Gerassimos G; Weis, Martin; Andújar, Dionisio; Rueda Ayala, Victor; Gerhards, Roland

    2014-02-01

    Site-specific weed management is the part of precision agriculture (PA) that tries to effectively control weed infestations with the least economical and environmental burdens. This can be achieved with the aid of ground-based or near-range sensors in combination with decision rules and precise application technologies. Near-range sensor technologies, developed for mounting on a vehicle, have been emerging for PA applications during the last three decades. These technologies focus on identifying plants and measuring their physiological status with the aid of their spectral and morphological characteristics. Cameras, spectrometers, fluorometers and distance sensors are the most prominent sensors for PA applications. The objective of this article is to describe-ground based sensors that have the potential to be used for weed detection and measurement of weed infestation level. An overview of current sensor systems is presented, describing their concepts, results that have been achieved, already utilized commercial systems and problems that persist. A perspective for the development of these sensors is given. © 2013 Society of Chemical Industry.

  15. Ozone vertical distribution retrieval from ground-based high resolution infrared solar spectra

    Science.gov (United States)

    Pougatchev, N. S.; Connor, B. J.; Rinsland, C. P.

    1995-01-01

    A practical procedure for the retrieval of ozone vertical profiles from ground-based high resolution Fourier transform infrared solar spectra has been developed. The analysis is based on a multilayer line-by-line forward model and a semi-empirical version of the optimal estimation inversion method of Rodgers. The 1002.6-1003.2 cm(exp -1) spectral interval has been selected for the analysis on the basis of synthetic spectrum calculations. This interval contains numerous ozone lines covering a range of intensities and providing retrieval sensitivity from ground level to about 35 km. Characterization of the method and an error analysis have been performed. For a spectral resolution of 0.05-0.01 cm(exp -1) and a signal-to-noise ratio greater than or equal to 100 the retrieval is stable with a vertical resolution of approximately 5 km attainable near the surface degrading to approximately 10 km in the stratosphere. Synthetic spectra studies show that the a priori profile and weak constraints selected for the retrievals introduce no significant biases for a wide range of ozone profiles.

  16. Relationship between soft stratum thickness and predominant frequency of ground based on microtremor observation data

    Science.gov (United States)

    Chia, Kenny; Lau, Tze Liang

    2017-07-01

    Despite categorized as low seismicity group, until being affected by distant earthquake ground motion from Sumatra and the recent 2015 Sabah Earthquake, Malaysia has come to realize that seismic hazard in the country is real and has the potential to threaten the public safety and welfare. The major concern in this paper is to study the effect of local site condition, where it could amplify the magnitude of ground vibration at sites. The aim for this study is to correlate the thickness of soft stratum with the predominant frequency of soil. Single point microtremor measurements were carried out at 24 selected points where the site investigation reports are available. Predominant period and frequency at each site are determined by Nakamura's method. The predominant period varies from 0.22 s to 0.98 s. Generally, the predominant period increases when getting closer to the shoreline which has thicker sediments. As far as the thickness of the soft stratum could influence the amplification of seismic wave, the advancement of micotremor observation to predict the thickness of soft stratum (h) from predominant frequency (fr) is of the concern. Thus an empirical relationship h =54.917 fr-1.314 is developed based on the microtremor observation data. The empirical relationship will be benefited in the prediction of thickness of soft stratum based on microtremor observation for seismic design with minimal cost compared to conventional boring method.

  17. Ground-based observation of emission lines from the corona of a red-dwarf star.

    Science.gov (United States)

    Schmitt, J H; Wichmann, R

    2001-08-02

    All 'solar-like' stars are surrounded by coronae, which contain magnetically confined plasma at temperatures above 106 K. (Until now, only the Sun's corona could be observed in the optical-as a shimmering envelope during a total solar eclipse.) As the underlying stellar 'surfaces'-the photospheres-are much cooler, some non-radiative process must be responsible for heating the coronae. The heating mechanism is generally thought to be magnetic in origin, but is not yet understood even for the case of the Sun. Ultraviolet emission lines first led to the discovery of the enormous temperature of the Sun's corona, but thermal emission from the coronae of other stars has hitherto been detectable only from space, at X-ray wavelengths. Here we report the detection of emission from highly ionized iron (Fe XIII at 3,388.1 A) in the corona of the red-dwarf star CN Leonis, using a ground-based telescope. The X-ray flux inferred from our data is consistent with previously measured X-ray fluxes, and the non-thermal line width of 18.4 km s-1 indicates great similarities between solar and stellar coronal heating mechanisms. The accessibility and spectral resolution (45,000) of the ground-based instrument are much better than those of X-ray satellites, so a new window to the study of stellar coronae has been opened.

  18. Proceedings of the 2011 Monitoring Research Review: Ground-Based Nuclear Explosion Monitoring Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Wetovsky, Marvin A. [Editor; Patterson, Eileen F. [Editor; Sandoval, Marisa N. [Editor

    2011-09-13

    These proceedings contain papers prepared for the Monitoring Research Review 2011: Ground-Based Nuclear Explosion Monitoring Technologies, held 13-15 September, 2011 in Tucson, Arizona. These papers represent the combined research related to ground-based nuclear explosion monitoring funded by the National Nuclear Security Administration (NNSA), Defense Threat Reduction Agency (DTRA), Air Force Research Laboratory (AFRL), US Army Space and Missile Defense Command, Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), National Science Foundation (NSF), and other invited sponsors. The scientific objectives of the research are to improve the United States' capability to detect, locate, and identify nuclear explosions. The purpose of the meeting is to provide the sponsoring agencies, as well as potential users, an opportunity to review research accomplished during the preceding year and to discuss areas of investigation for the coming year. For the researchers, it provides a forum for the exchange of scientific information toward achieving program goals, and an opportunity to discuss results and future plans. Paper topics include: seismic regionalization and calibration; detection and location of sources; wave propagation from source to receiver; the nature of seismic sources, including mining practices; hydroacoustic, infrasound, and radionuclide methods; on-site inspection; and data processing.

  19. GROUND-BASED TRANSIT OBSERVATIONS OF THE SUPER-EARTH 55 Cnc e

    Energy Technology Data Exchange (ETDEWEB)

    De Mooij, E. J. W. [Astronomy and Astrophysics, University of Toronto, Toronto (Canada); López-Morales, M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA (United States); Karjalainen, R.; Hrudkova, M. [Isaac Newton Group of Telescopes, La Palma (Spain); Jayawardhana, Ray, E-mail: demooij@astro.utoronto.ca [Physics and Astronomy, York University, Toronto (Canada)

    2014-12-20

    We report the first ground-based detections of the shallow transit of the super-Earth exoplanet 55 Cnc e using a 2 m class telescope. Using differential spectrophotometry, we observed one transit in 2013 and another in 2014, with average spectral resolutions of ∼700 and ∼250, spanning the Johnson BVR photometric bands. We find a white light planet-to-star radius ratio of 0.0190{sub −0.0027}{sup +0.0023} from the 2013 observations and 0.0200{sub −0.0018}{sup +0.0017} from the 2014 observations. The two data sets combined result in a radius ratio of 0.0198{sub −0.0014}{sup +0.0013}. These values are all in agreement with previous space-based results. Scintillation noise in the data prevents us from placing strong constraints on the presence of an extended hydrogen-rich atmosphere. Nevertheless, our detections of 55 Cnc e in transit demonstrate that moderate-sized telescopes on the ground will be capable of routine follow-up observations of super-Earth candidates discovered by the Transiting Exoplanet Survey Satellite around bright stars. We expect it also will be possible to place constraints on the atmospheric characteristics of those planets by devising observational strategies to minimize scintillation noise.

  20. Proceedings of the 27th Seismic Research Review: Ground-Based Nuclear Explosion Monitoring Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Wetovsky, Marvin A. [Editor; Benson, Jody [Editor; Patterson, Eileen F. [Editor

    2005-09-20

    These proceedings contain papers prepared for the 27th Seismic Research Review: Ground-Based Nuclear Explosion Monitoring Technologies, held 20-22 September, 2005 in Rancho Mirage, California. These papers represent the combined research related to ground-based nuclear explosion monitoring funded by the National Nuclear Security Administration (NNSA), Air Force Technical Applications Center (AFTAC), Air Force Research Laboratory (AFRL), US Army Space and Missile Defense Command, and other invited sponsors. The scientific objectives of the research are to improve the United States capability to detect, locate, and identify nuclear explosions. The purpose of the meeting is to provide the sponsoring agencies, as well as potential users, an opportunity to review research accomplished during the preceding year and to discuss areas of investigation for the coming year. For the researchers, it provides a forum for the exchange of scientific information toward achieving program goals, and an opportunity to discuss results and future plans. Paper topics include: seismic regionalization and calibration; detection and location of sources; wave propagation from source to receiver; the nature of seismic sources, including mining practices; hydroacoustic, infrasound, and radionuclide methods; on-site inspection; and data processing.

  1. Towards the development of tamper-resistant, ground-based mobile sensor nodes

    Science.gov (United States)

    Mascarenas, David; Stull, Christopher; Farrar, Charles

    2011-11-01

    Mobile sensor nodes hold great potential for collecting field data using fewer resources than human operators would require and potentially requiring fewer sensors than a fixed-position sensor array. It would be very beneficial to allow these mobile sensor nodes to operate unattended with a minimum of human intervention. In order to allow mobile sensor nodes to operate unattended in a field environment, it is imperative that they be capable of identifying and responding to external agents that may attempt to tamper with, damage or steal the mobile sensor nodes, while still performing their data collection mission. Potentially hostile external agents could include animals, other mobile sensor nodes, or humans. This work will focus on developing control policies to help enable a mobile sensor node to identify and avoid capture by a hostile un-mounted human. The work is developed in a simulation environment, and demonstrated using a non-holonomic, ground-based mobile sensor node. This work will be a preliminary step toward ensuring the cyber-physical security of ground-based mobile sensor nodes that operate unattended in potentially unfriendly environments.

  2. Understanding the Laminar Distribution of Tropospheric Ozone from Ground-Based, Airborne, Spaceborne, and Modeling Perspectives

    Science.gov (United States)

    Newchurch, Mike; Johnson, Matthew S.; Huang, Guanyu; Kuang, Shi; Wang, Lihua; Chance, Kelly; Liu, Xiong

    2016-01-01

    Laminar ozone structure is a ubiquitous feature of tropospheric-ozone distributions resulting from dynamic and chemical atmospheric processes. Understanding the characteristics of these ozone laminae and the mechanisms responsible for producing them is important to outline the transport pathways of trace gases and to quantify the impact of different sources on tropospheric background ozone. In this study, we present a new method to detect ozone laminae to understand their climatological characteristics of occurrence frequency in terms of thickness and altitude. We employ both ground-based and airborne ozone lidar measurements and other synergistic observations and modeling to investigate the sources and mechanisms such as biomass burning transport, stratospheric intrusion, lightning-generated NOx, and nocturnal low-level jets that are responsible for depleted or enhanced tropospheric ozone layers. Spaceborne (e.g., OMI (Ozone Monitoring Instrument), TROPOMI (Tropospheric Monitoring Instrument), TEMPO (Tropospheric Emissions: Monitoring of Pollution)) measurements of these laminae will observe greater horizontal extent and lower vertical resolution than balloon-borne or lidar measurements will quantify. Using integrated ground-based, airborne, and spaceborne observations in a modeling framework affords insight into how to gain knowledge of both the vertical and horizontal evolution of these ubiquitous ozone laminae.

  3. Ground-Based Transit Observations of the Super-Earth 55 Cnc e

    CERN Document Server

    de Mooij, E J W; Karjalainen, R; Hrudkova, M; Jayawardhana, R

    2014-01-01

    We report the first ground-based detections of the shallow transit of the super-Earth exoplanet 55 Cnc e using a 2-meter-class telescope. Using differential spectrophotometry, we observed one transit in 2013 and another in 2014, with average spectral resolutions of ~700 and ~250, spanning the Johnson BVR photometric bands. We find a white-light planet-to-star radius ratio of 0.0190 -0.0027+0.0023 from the 2013 observations and 0.0200 -0.0018+0.0017 from the 2014 observations. The two datasets combined results in a radius ratio of 0.0198 -0.0014+0.0013. These values are all in agreement with previous space-based results. Scintillation noise in the data prevents us from placing strong constraints on the presence of an extended hydrogen-rich atmosphere. Nevertheless, our detections of 55 Cnc e in transit demonstrate that moderate-size telescopes on the ground will be capable of routine follow-up observations of super-Earth candidates discovered by the Transiting Exoplanet Survey Satellite (TESS) around bright st...

  4. Ground Based Retrievals of Small Ice Crystals and Water Phase in Arctic Cirrus

    Science.gov (United States)

    Mishra, Subhashree; Mitchell, David L.; DeSlover, Daniel

    2009-03-01

    The microphysical properties of cirrus clouds are uncertain due to the problem of ice particles shattering at the probe inlet upon sampling. To facilitate better estimation of small ice crystal concentrations in cirrus clouds, a new ground-based remote sensing technique has been used in combination with in situ aircraft measurements. Data from the Mixed-Phase Arctic Cloud Experiment (M-PACE), conducted at the north slope of Alaska (winter 2004), have been used to test a new method for retrieving the liquid water path (LWP) and ice water path (IWP) in mixed phase clouds. The framework of the retrieval algorithm consists of the modified anomalous diffraction approximation or MADA (for mixed phase cloud optical properties), a radar reflectivity-ice microphysics relationship and a temperature-dependent ice particle size distribution (PSD) scheme. Cloud thermal emission measurements made by the ground-based Atmospheric Emitted Radiance Interferometer (AERI) yield information on the total water path (TWP) while reflectivity measurements from the Millimeter Cloud Radar (MMCR) are used to derive the IWP. The AERI is also used to indicate the concentration of small ice crystals (DBeer's law absorption. While this is still a work in progress, the anticipated products from this AERI-radar retrieval scheme are the IWP, LWP, small-to-large ice crystal number concentration ratio and effective diameter for cirrus, as well as the ice particle number concentration for a given ice water content (IWC).

  5. Evaluation of brightness temperature from a forward model of ground-based microwave radiometer

    Indian Academy of Sciences (India)

    S Rambabu; J S Pillai; A Agarwal; G Pandithurai

    2014-06-01

    Ground-based microwave radiometers are getting great attention in recent years due to their capability to profile the temperature and humidity at high temporal and vertical resolution in the lower troposphere. The process of retrieving these parameters from the measurements of radiometric brightness temperature () includes the inversion algorithm, which uses the background information from a forward model. In the present study, an algorithm development and evaluation of this forward model for a ground-based microwave radiometer, being developed by Society for Applied Microwave Electronics Engineering and Research (SAMEER) of India, is presented. Initially, the analysis of absorption coefficient and weighting function at different frequencies was made to select the channels. Further the range of variation of for these selected channels for the year 2011, over the two stations Mumbai and Delhi is discussed. Finally the comparison between forward-model simulated s and radiometer measured s at Mahabaleshwar (73.66°E and 17.93°N) is done to evaluate the model. There is good agreement between model simulations and radiometer observations, which suggests that these forward model simulations can be used as background for inversion models for retrieving the temperature and humidity profiles.

  6. Proceedings of the 29th Monitoring Research Review: Ground-Based Nuclear Explosion Monitoring Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Wetovsky, Marvin A. [Editor; Benson, Jody [Editor; Patterson, Eileen F. [Editor

    2007-09-25

    These proceedings contain papers prepared for the 29th Monitoring Research Review: Ground-Based Nuclear Explosion Monitoring Technologies, held 25-27 September, 2007 in Denver, Colorado. These papers represent the combined research related to ground-based nuclear explosion monitoring funded by the National Nuclear Security Administration (NNSA), Air Force Technical Applications Center (AFTAC), Air Force Research Laboratory (AFRL), US Army Space and Missile Defense Command, Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), and other invited sponsors. The scientific objectives of the research are to improve the United States capability to detect, locate, and identify nuclear explosions. The purpose of the meeting is to provide the sponsoring agencies, as well as potential users, an opportunity to review research accomplished during the preceding year and to discuss areas of investigation for the coming year. For the researchers, it provides a forum for the exchange of scientific information toward achieving program goals, and an opportunity to discuss results and future plans. Paper topics include: seismic regionalization and calibration; detection and location of sources; wave propagation from source to receiver; the nature of seismic sources, including mining practices; hydroacoustic, infrasound, and radionuclide methods; on-site inspection; and data processing.

  7. Proceedings of the 28th Seismic Research Review: Ground-Based Nuclear Explosion Monitoring Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Wetovsky, Marvin A. [Editor; Benson, Jody [Editor; Patterson, Eileen F. [Editor

    2006-09-19

    These proceedings contain papers prepared for the 28th Seismic Research Review: Ground-Based Nuclear Explosion Monitoring Technologies, held 19-21 September, 2006 in Orlando, Florida. These papers represent the combined research related to ground-based nuclear explosion monitoring funded by the National Nuclear Security Administration (NNSA), Air Force Technical Applications Center (AFTAC), Air Force Research Laboratory (AFRL), US Army Space and Missile Defense Command, Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), and other invited sponsors. The scientific objectives of the research are to improve the United States capability to detect, locate, and identify nuclear explosions. The purpose of the meeting is to provide the sponsoring agencies, as well as potential users, an opportunity to review research accomplished during the preceding year and to discuss areas of investigation for the coming year. For the researchers, it provides a forum for the exchange of scientific information toward achieving program goals, and an opportunity to discuss results and future plans. Paper topics include: seismic regionalization and calibration; detection and location of sources; wave propagation from source to receiver; the nature of seismic sources, including mining practices; hydroacoustic, infrasound, and radionuclide methods; on-site inspection; and data processing.

  8. Proceedings of the 30th Monitoring Research Review: Ground-Based Nuclear Explosion Monitoring

    Energy Technology Data Exchange (ETDEWEB)

    Wetovsky, Marv A [Los Alamos National Laboratory; Aguilar-chang, Julio [Los Alamos National Laboratory; Arrowsmith, Marie [Los Alamos National Laboratory; Arrowsmith, Stephen [Los Alamos National Laboratory; Baker, Diane [Los Alamos National Laboratory; Begnaud, Michael [Los Alamos National Laboratory; Harste, Hans [Los Alamos National Laboratory; Maceira, Monica [Los Alamos National Laboratory; Patton, Howard [Los Alamos National Laboratory; Phillips, Scott [Los Alamos National Laboratory; Randall, George [Los Alamos National Laboratory; Revelle, Douglas [Los Alamos National Laboratory; Rowe, Charlotte [Los Alamos National Laboratory; Stead, Richard [Los Alamos National Laboratory; Steck, Lee [Los Alamos National Laboratory; Whitaker, Rod [Los Alamos National Laboratory; Yang, Xiaoning [Los Alamos National Laboratory

    2008-09-23

    These proceedings contain papers prepared for the 30th Monitoring Research Review: Ground-Based Nuclear Explosion Monitoring Technologies, held 23-25 September, 2008 in Portsmouth, Virginia. These papers represent the combined research related to ground-based nuclear explosion monitoring funded by the National Nuclear Security Administration (NNSA), Air Force Technical Applications Center (AFTAC), Air Force Research Laboratory (AFRL), US Army Space and Missile Defense Command, Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), and other invited sponsors. The scientific objectives of the research are to improve the United States’ capability to detect, locate, and identify nuclear explosions. The purpose of the meeting is to provide the sponsoring agencies, as well as potential users, an opportunity to review research accomplished during the preceding year and to discuss areas of investigation for the coming year. For the researchers, it provides a forum for the exchange of scientific information toward achieving program goals, and an opportunity to discuss results and future plans. Paper topics include: seismic regionalization and calibration; detection and location of sources; wave propagation from source to receiver; the nature of seismic sources, including mining practices; hydroacoustic, infrasound, and radionuclide methods; on-site inspection; and data processing.

  9. Proceedings of the 2010 Monitoring Research Review: Ground-Based Nuclear Explosion Monitoring Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Wetovsky, Marvin A [Editor; Patterson, Eileen F [Editor

    2010-09-21

    These proceedings contain papers prepared for the Monitoring Research Review 2010: Ground-Based Nuclear Explosion Monitoring Technologies, held 21-23 September, 2010 in Orlando, Florida,. These papers represent the combined research related to ground-based nuclear explosion monitoring funded by the National Nuclear Security Administration (NNSA), Air Force Research Laboratory (AFRL), US Army Space and Missile Defense Command, National Science Foundation (NSF), Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO), and other invited sponsors. The scientific objectives of the research are to improve the United States capability to detect, locate, and identify nuclear explosions. The purpose of the meeting is to provide the sponsoring agencies, as well as potential users, an opportunity to review research accomplished during the preceding year and to discuss areas of investigation for the coming year. For the researchers, it provides a forum for the exchange of scientific information toward achieving program goals, and an opportunity to discuss results and future plans. Paper topics include: seismic regionalization and calibration; detection and location of sources; wave propagation from source to receiver; the nature of seismic sources, including mining practices; hydroacoustic, infrasound, and radionuclide methods; on-site inspection; and data processing.

  10. Proceedings of the 2009 Monitoring Research Review: Ground-Based Nuclear Explosion Monitoring Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Wetovsky, Marv A [Los Alamos National Laboratory; Aguilar - Chang, Julio [Los Alamos National Laboratory; Anderson, Dale [Los Alamos National Laboratory; Arrowsmith, Marie [Los Alamos National Laboratory; Arrowsmith, Stephen [Los Alamos National Laboratory; Baker, Diane [Los Alamos National Laboratory; Begnaud, Michael [Los Alamos National Laboratory; Harste, Hans [Los Alamos National Laboratory; Maceira, Monica [Los Alamos National Laboratory; Patton, Howard [Los Alamos National Laboratory; Phillips, Scott [Los Alamos National Laboratory; Randall, George [Los Alamos National Laboratory; Rowe, Charlotte [Los Alamos National Laboratory; Stead, Richard [Los Alamos National Laboratory; Steck, Lee [Los Alamos National Laboratory; Whitaker, Rod [Los Alamos National Laboratory; Yang, Xiaoning ( David ) [Los Alamos National Laboratory

    2009-09-21

    These proceedings contain papers prepared for the Monitoring Research Review 2009: Ground -Based Nuclear Explosion Monitoring Technologies, held 21-23 September, 2009 in Tucson, Arizona,. These papers represent the combined research related to ground-based nuclear explosion monitoring funded by the National Nuclear Security Administration (NNSA), Air Force Research Laboratory (AFRL), US Army Space and Missile Defense Command, Comprehensive Test Ban Treaty Organization (CTBTO), and other invited sponsors. The scientific objectives of the research are to improve the United States’ capability to detect, locate, and identify nuclear explosions. The purpose of the meeting is to provide the sponsoring agencies, as well as potential users, an opportunity to review research accomplished during the preceding year and to discuss areas of investigation for the coming year. For the researchers, it provides a forum for the exchange of scientific information toward achieving program goals, and an opportunity to discuss results and future plans. Paper topics include: seismic regionalization and calibration; detection and location of sources; wave propagation from source to receiver; the nature of seismic sources, including mining practices; hydroacoustic, infrasound, and radionuclide methods; on-site inspection; and data processing.

  11. De-mystifying earned value management for ground based astronomy projects, large and small

    Science.gov (United States)

    Norton, Timothy; Brennan, Patricia; Mueller, Mark

    2014-08-01

    The scale and complexity of today's ground based astronomy projects have justifiably required Principal Investigator's and their project teams to adopt more disciplined management processes and tools in order to achieve timely and accurate quantification of the progress and relative health of their projects. Earned Value Management (EVM) is one such tool. Developed decades ago and used extensively in the defense and construction industries, and now a requirement of NASA projects greater than $20M; EVM has gained a foothold in ground-based astronomy projects. The intent of this paper is to de-mystify EVM by discussing the fundamentals of project management, explaining how EVM fits with existing principles, and describing key concepts every project can use to implement their own EVM system. This paper also discusses pitfalls to avoid during implementation and obstacles to its success. The authors report on their organization's most recent experience implementing EVM for the GMT-Consortium Large Earth Finder (G-CLEF) project. G-CLEF is a fiber-fed, optical echelle spectrograph that has been selected as a first light instrument for the Giant Magellan Telescope (GMT), planned for construction at the Las Campanas Observatory in Chile's Atacama Desert region.

  12. Augmenting WFIRST Microlensing with a Ground-based Optical Telescope Network

    CERN Document Server

    Zhu, Wei

    2016-01-01

    Augmenting the WFIRST microlensing campaigns with intensive observations from a ground-based network of wide-field survey telescopes would have several major advantages. First, it would enable one-dimensional (1-D) microlens parallax measurements over the entire mass range $M\\gtrsim M_\\oplus$. For luminous lenses, such 1-D parallax measurements can be promoted to complete solutions (mass, distance, transverse velocity) by high-resolution imaging a few years after the observations. This would provide crucial information not only about the hosts of planets and other lenses, but also enable a much more precise Galactic model. The addition of such a ground-based survey would also yield full 2-D vector parallax measurements, with largest sensitivity to low-mass lenses, which (being non-luminous) are not subject to followup imaging. These 2-D parallax measurements will directly yield mass and distance measurements for most planetary and binary events. It would also yield additional complete solutions for single-len...

  13. Atmospheric aerosol characterization with a ground-based SPEX spectropolarimetric instrument

    Directory of Open Access Journals (Sweden)

    G. van Harten

    2014-06-01

    Full Text Available Characterization of atmospheric aerosols is important for understanding their impact on health and climate. A wealth of aerosol parameters can be retrieved from multi-angle, multi-wavelength radiance and polarization measurements of the clear sky. We developed a ground-based SPEX instrument (groundSPEX for accurate spectropolarimetry, based on the passive, robust, athermal and snapshot spectral polarization modulation technique, and hence ideal for field deployment. It samples the scattering phase function in the principal plane in an automated fashion, using a motorized pan/tilt unit and automatic exposure time detection. Extensive radiometric and polarimetric calibrations were performed, yielding values for both random noise and systematic uncertainties. The absolute polarimetric accuracy at low degrees of polarization is established to be ~ 5 × 10−3. About 70 measurement sequences have been performed throughout four clear-sky days at Cabauw, the Netherlands. Several aerosol parameters were retrieved: aerosol optical thickness, effective radius, and complex refractive index for fine and coarse mode. The results are in good agreement with the co-located AERONET products, with a correlation coefficient of ρ = 0.932 for the total aerosol optical thickness at 550 nm.

  14. Magnetocaloric effect in M-pyrazole-[Nb(CN)(8)] (M = Ni, Mn) molecular compounds.

    Science.gov (United States)

    Fitta, Magdalena; Bałanda, Maria; Mihalik, Marian; Pełka, Robert; Pinkowicz, Dawid; Sieklucka, Barbara; Zentkova, Maria

    2012-12-19

    We report a study of magnetocaloric effect (MCE) in cyanido-bridged {[M(II)(pyrazole)(4)](2)[Nb(IV)(CN)(8)]·4H(2)O}(n) molecular compounds where M = Ni, Mn, pyrazole = C(3)H(4)N(2). The substances show a sharp phase transition to a long range magnetically ordered state, with ferromagnetic coupling between M and Nb sublattices in the case of the Ni-based sample 1 (T(c) = 13.4 K) and ferrimagnetic coupling for the Mn-based sample 2 (T(c) = 23.8 K). The magnetic entropy change ΔS due to applied field change ΔH as a function of temperature was determined by the magnetization and heat capacity measurements. The maximum value of ΔS at μ(0)ΔH = 5 T is 6.1 J mol(-1) K(-1) (5.9 J kg(-1) K(-1)) for 1 at T = 14 K and 6.7 J mol(-1) K(-1) (6.5 J kg(-1) K(-1)) for 2 at T = 25 K. MCE data at different applied fields have been presented as one universal curve, which confirms magnetic transitions in 1 and 2 to be of second order. The temperature dependences of the n exponent characterizing the dependence of ΔS on ΔH have been obtained. The n(T(c)) values, consistent with the shape of the magnetization curves, pointed to the 3D Heisenberg behaviour for 2 and some anisotropy, probably of the XY type, for 1. The (H/T(c))(2/3) dependence of the maximum entropy change has been tested in the ferrimagnetic Mn(2)-L-[Nb(CN)(8)] (L = C(3)H(4)N(2), C(4)H(4)N(2)) series.

  15. Formulation of geopotential difference determination using optical-atomic clocks onboard satellites and on ground based on Doppler cancellation system

    Science.gov (United States)

    Shen, Ziyu; Shen, Wen-Bin; Zhang, Shuangxi

    2016-08-01

    In this study, we propose an approach for determining the geopotential difference using high-frequency-stability microwave links between satellite and ground station based on Doppler cancellation system. Suppose a satellite and a ground station are equipped with precise optical-atomic clocks (OACs) and oscillators. The ground oscillator emits a signal with frequency fa towards the satellite and the satellite receiver (connected with the satellite oscillator) receives this signal with frequency fb which contains the gravitational frequency shift effect and other signals and noises. After receiving this signal, the satellite oscillator transmits and emits, respectively, two signals with frequencies fb and fc towards the ground station. Via Doppler cancellation technique, the geopotential difference between the satellite and the ground station can be determined based on gravitational frequency shift equation by a combination of these three frequencies. For arbitrary two stations on ground, based on similar procedures as described above, we may determine the geopotential difference between these two stations via a satellite. Our analysis shows that the accuracy can reach 1 m2 s- 2 based on the clocks' inaccuracy of about 10-17 (s s-1) level. Since OACs with instability around 10-18 in several hours and inaccuracy around 10-18 level have been generated in laboratory, the proposed approach may have prospective applications in geoscience, and especially, based on this approach a unified world height system could be realized with one-centimetre level accuracy in the near future.

  16. Functional proteomic analysis revealed ground-base ion radiations cannot reflect biological effects of space radiations of rice

    Science.gov (United States)

    Wang, Wei; Sun, Yeqing; Zhao, Qian; Han, Lu

    2016-07-01

    Highly ionizing radiation (HZE) in space is considered as main factor causing biological effects. Radiobiological studies during space flights are unrepeatable due to the variable space radiation environment, ground-base ion radiations are usually performed to simulate of the space biological effect. Spaceflights present a low-dose rate (0.1˜~0.3mGy/day) radiation environment inside aerocrafts while ground-base ion radiations present a much higher dose rate (100˜~500mGy/min). Whether ground-base ion radiation can reflect effects of space radiation is worth of evaluation. In this research, we compared the functional proteomic profiles of rice plants between on-ground simulated HZE particle radiation and spaceflight treatments. Three independent ground-base seed ionizing radiation experiments with different cumulative doses (dose range: 2˜~20000mGy) and different liner energy transfer (LET) values (13.3˜~500keV/μμm) and two independent seed spaceflight experiments onboard Chinese 20th satellite and SZ-6 spacecraft were carried out. Alterations in the proteome were analyzed by two-dimensional difference gel electrophoresis (2-D DIGE) with MALDI-TOF/TOF mass spectrometry identifications. 45 and 59 proteins showed significant (pmetabolic process, protein folding and phosphorylation. The results implied that ground-base radiations cannot truly reflect effects of spaceflight radiations, ground-base radiation was a kind of indirect effect to rice causing oxidation and metabolism stresses, but space radiation was a kind of direct effect leading to macromolecule (DNA and protein) damage and signal pathway disorders. This functional proteomic analysis work might provide a new evaluation method for further on-ground simulated HZE radiation experiments.

  17. Heat-stop structure design with high cooling efficiency for large ground-based solar telescope.

    Science.gov (United States)

    Liu, Yangyi; Gu, Naiting; Rao, Changhui; Li, Cheng

    2015-07-20

    A heat-stop is one of the most important thermal control devices for a large ground-based solar telescope. For controlling the internal seeing effect, the temperature difference between the heat-stop and the ambient environment needs to be reduced, and a heat-stop with high cooling efficiency is required. In this paper, a novel design concept for the heat-stop, in which a multichannel loop cooling system is utilized to obtain higher cooling efficiency, is proposed. To validate the design, we analyze and compare the cooling efficiency for the multichannel and existing single-channel loop cooling system under the same conditions. Comparative results show that the new design obviously enhances the cooling efficiency of the heat-stop, and the novel design based on the multichannel loop cooling system is obviously better than the existing design by increasing the thermal transfer coefficient.

  18. Autonomous landing of a helicopter UAV with a ground-based multisensory fusion system

    Science.gov (United States)

    Zhou, Dianle; Zhong, Zhiwei; Zhang, Daibing; Shen, Lincheng; Yan, Chengping

    2015-02-01

    In this study, this paper focus on the vision-based autonomous helicopter unmanned aerial vehicle (UAV) landing problems. This paper proposed a multisensory fusion to autonomous landing of an UAV. The systems include an infrared camera, an Ultra-wideband radar that measure distance between UAV and Ground-Based system, an PAN-Tilt Unit (PTU). In order to identify all weather UAV targets, we use infrared cameras. To reduce the complexity of the stereovision or one-cameral calculating the target of three-dimensional coordinates, using the ultra-wideband radar distance module provides visual depth information, real-time Image-PTU tracking UAV and calculate the UAV threedimensional coordinates. Compared to the DGPS, the test results show that the paper is effectiveness and robustness.

  19. Unmanned Ground Vehicle Navigation Using Brain Emotional Learning Based Intelligent Controller (BELBIC

    Directory of Open Access Journals (Sweden)

    Alvaro Vargas-Clara

    2015-02-01

    Full Text Available In this paper, we implement a novel control strategy for navigation of an Unmanned Ground Vehicle (UGV. This strategy consisted in the development and implementation of the Brain Emotional Learning Based Intelligent Controller (BELBIC for heading, and path control of a UGV. BELBIC is an intelligent controller based on the model of the Amygdala-Orbitofrontal system of mammalians, which is a region in the brain known to be responsible for emotional learning process. Simulation of this controller for the cases of heading, and path control showed to be very robust and adaptable to dynamical changes in the plant. A comparison between BELBIC and a traditional PID control is presented to illustrate the performance of this control strategy.

  20. Space life sciences: ground-based iron-ion biology and physics, including shielding.

    Science.gov (United States)

    2005-01-01

    This session of the 35th Scientific Assembly of COSPAR focuses on recent advances in ground-based studies of high-energy (mainly 1 GeV/nucleon) iron ions. The theme is interdisciplinary in nature and encompasses both physics and biology reports. Manned space missions, including those of the International Space Station and the planned Mars mission, will require the extended presence of crew members in space. As such, a better understanding in shielding design--in radiation detection as well as radio-protection based on simulating studies--is much needed. On the other hand, a better understanding of the basic mechanisms that modulate radiation sensitivity; in determining DNA double strand breaks, chromosomal aberrations, and the induction of apoptosis, will provide important information for an interventional approach.

  1. Ground-based testing of the dynamics of flexible space structures using band mechanisms

    Science.gov (United States)

    Yang, L. F.; Chew, Meng-Sang

    1991-01-01

    A suspension system based on a band mechanism is studied to provide the free-free conditions for ground based validation testing of flexible space structures. The band mechanism consists of a noncircular disk with a convex profile, preloaded by torsional springs at its center of rotation so that static equilibrium of the test structure is maintained at any vertical location; the gravitational force will be directly counteracted during dynamic testing of the space structure. This noncircular disk within the suspension system can be configured to remain unchanged for test articles with the different weights as long as the torsional spring is replaced to maintain the originally designed frequency ratio of W/k sub s. Simulations of test articles which are modeled as lumped parameter as well as continuous parameter systems, are also presented.

  2. Ground-based multisite observations of two transits of HD 80606b

    CERN Document Server

    Shporer, A; Dreizler, S; Colon, K D; Wood-Vasey, W M; Choi, P I; Morley, C; Moutou, C; Welsh, W F; Pollaco, D; Starkey, D; Adams, E; Barros, S C C; Bouchy, F; Cabrera-Lavers, A; Cerutti, S; Coban, L; Costello, K; Deeg, H; Diaz, R F; Esquerdo, G A; Fernandez, J; Fleming, S W; Ford, E B; Fulton, B J; Good, M; Hebrard, G; Holman, M J; Hunt, M; Kadakia, S; Lander, G; Lockhart, M; Mazeh, T; Morehead, R C; Nelson, B E; Nortmann, L; Reyes, F; Roebuck, E; Rudy, A R; Ruth, R; Simpson, E; Vincent, C; Weaver, G; Xie, J -W

    2010-01-01

    We present ground-based optical observations of the September 2009 and January 2010 transits of HD 80606b. Based on 3 partial light curves of the September 2009 event, we derive a midtransit time of T_c [HJD] = 2455099.196 +- 0.026, which is about 1 sigma away from the previously predicted time. We observed the January 2010 event from 9 different locations, with most phases of the transit being observed by at least 3 different teams. We determine a midtransit time of T_c [HJD] = 2455210.6502 +- 0.0064, which is within 1.3 sigma of the time derived from a Spitzer observation of the same event.

  3. The Holy Grail of Resource Assessment: Low Cost Ground-Based Measurements with Good Accuracy

    Energy Technology Data Exchange (ETDEWEB)

    Marion, Bill; Smith, Benjamin

    2017-06-22

    Using performance data from some of the millions of installed photovoltaic (PV) modules with micro-inverters may afford the opportunity to provide ground-based solar resource data critical for developing PV projects. The method used back-solves for the direct normal irradiance (DNI) and the diffuse horizontal irradiance (DHI) from the micro-inverter ac production data. When the derived values of DNI and DHI were then used to model the performance of other PV systems, the annual mean bias deviations were within +/- 4%, and only 1% greater than when the PV performance was modeled using high quality irradiance measurements. An uncertainty analysis shows the method better suited for modeling PV performance than using satellite-based global horizontal irradiance.

  4. A six-beam method to measure turbulence statistics using ground-based wind lidars

    DEFF Research Database (Denmark)

    Sathe, Ameya; Mann, Jakob; Vasiljevic, Nikola

    2015-01-01

    A so-called six-beam method is proposed to measure atmospheric turbulence using a ground-based wind lidar. This method requires measurement of the radial velocity variances at five equally spaced azimuth angles on the base of a scanning cone and one measurement at the centre of the scanning circle...... lidar (WindScanner), and the derived turbulence statistics (using both methods) such as the u and v variances are compared with those obtained from a reference cup anemometer and a wind vane at 89m height under different atmospheric stabilities. The measurements show that in comparison to the reference...... cup anemometer, depending on the atmospheric stability and the wind field component, the six-beam method measures between 85 and 101% of the reference turbulence, whereas the VAD method measures between 66 and 87% of the reference turbulence....

  5. A six-beam method to measure turbulence statistics using ground-based wind lidars

    DEFF Research Database (Denmark)

    Sathe, Ameya; Mann, Jakob; Vasiljevic, Nikola

    2014-01-01

    A so-called six-beam method is proposed to measure atmospheric turbulence using a ground-based wind lidar. This method requires measurement of the radial velocity variances at five equally spaced azimuth angles on the base of a scanning cone and one measurement at the center of the scanning circle...... lidar (WindScanner), and the derived turbulence statistics (using both methods) such as the u and v variances are compared with those obtained from a reference cup anemometer and a wind vane at 89m height under different atmospheric stabilities. The measurements show that in comparison to the reference...... cup anemometer, depending on the atmospheric stability and the wind field component, the six-beam method measures between 85–101% of the reference turbulence, whereas the VAD method measures between 66–87% of the reference turbulence....

  6. A computerized data base of nitrate concentrations in Indiana ground water

    Science.gov (United States)

    Risch, M.R.; Cohen, D.A.

    1995-01-01

    As part of a cooperative study with the Indiana Department of Environmental Management, the U.S. Geological Survey compiled a computerized data base of nitrate concentrations in Indiana ground water. The data included nitrate determinations from more than 29 studies by five Federal and State agencies during June 1973 through August 1991. The National Water Information System software of the U.S. Geological Survey was used to store the data at the U.S. Geological Survey office in Indianapolis, Indiana. Electronic data sets were converted to a standard format of well data, sample data, and analytical data. Data were screened by several error-checking procedures before they were retained in the data base; they were examined for potential duplicates of well location and name.

  7. Risk-based prioritization of ground water threatening point sources at catchment and regional scales

    DEFF Research Database (Denmark)

    Overheu, Niels Døssing; Tuxen, Nina; Flyvbjerg, John;

    2014-01-01

    framework has been developed to enable a systematic and transparent risk assessment and prioritization of contaminant point sources, considering the local, catchment, or regional scales (Danish EPA, 2011, 2012). The framework has been tested in several catchments in Denmark with different challenges...... and needs, and two of these are presented. Based on the lessons learned, the Danish EPA has prepared a handbook to guide the user through the steps in a risk-based prioritization (Danish EPA, 2012). It provides guidance on prioritization both in an administratively defined area such as a Danish Region......, and within the bounds of a specified ground water catchment. The handbook presents several approaches in order to prevent the prioritization from foundering because of a lack of data or an inappropriate level of complexity. The developed prioritization tools, possible graphical presentation and use...

  8. Ground based mobile isotopic methane measurements in the Front Range, Colorado

    Science.gov (United States)

    Vaughn, B. H.; Rella, C.; Petron, G.; Sherwood, O.; Mielke-Maday, I.; Schwietzke, S.

    2014-12-01

    Increased development of unconventional oil and gas resources in North America has given rise to attempts to monitor and quantify fugitive emissions of methane from the industry. Emission estimates of methane from oil and gas basins can vary significantly from one study to another as well as from EPA or State estimates. New efforts are aimed at reconciling bottom-up, or inventory-based, emission estimates of methane with top-down estimates based on atmospheric measurements from aircraft, towers, mobile ground-based vehicles, and atmospheric models. Attributing airborne measurements of regional methane fluxes to specific sources is informed by ground-based measurements of methane. Stable isotopic measurements (δ13C) of methane help distinguish between emissions from the O&G industry, Confined Animal Feed Operations (CAFO), and landfills, but analytical challenges typically limit meaningful isotopic measurements to individual point sampling. We are developing a toolbox to use δ13CH4 measurements to assess the partitioning of methane emissions for regions with multiple methane sources. The method was applied to the Denver-Julesberg Basin. Here we present data from continuous isotopic measurements obtained over a wide geographic area by using MegaCore, a 1500 ft. tube that is constantly filled with sample air while driving, then subsequently analyzed at slower rates using cavity ring down spectroscopy (CRDS). Pressure, flow and calibration are tightly controlled allowing precise attribution of methane enhancements to their point of collection. Comparisons with point measurements are needed to confirm regional values and further constrain flux estimates and models. This effort was made in conjunction with several major field campaigns in the Colorado Front Range in July-August 2014, including FRAPPÉ (Front Range Air Pollution and Photochemistry Experiment), DISCOVER-AQ, and the Air Water Gas NSF Sustainability Research Network at the University of Colorado.

  9. A Near-Term Concept for Trajectory Based Operations with Air/Ground Data Link Communication

    Science.gov (United States)

    McNally, David; Mueller, Eric; Thipphavong, David; Paielli, Russell; Cheng, Jinn-Hwei; Lee, Chuhan; Sahlman, Scott; Walton, Joe

    2010-01-01

    An operating concept and required system components for trajectory-based operations with air/ground data link for today's en route and transition airspace is proposed. Controllers are fully responsible for separation as they are today, and no new aircraft equipage is required. Trajectory automation computes integrated solutions to problems like metering, weather avoidance, traffic conflicts and the desire to find and fly more time/fuel efficient flight trajectories. A common ground-based system supports all levels of aircraft equipage and performance including those equipped and not equipped for data link. User interface functions for the radar controller's display make trajectory-based clearance advisories easy to visualize, modify if necessary, and implement. Laboratory simulations (without human operators) were conducted to test integrated operation of selected system components with uncertainty modeling. Results are based on 102 hours of Fort Worth Center traffic recordings involving over 37,000 individual flights. The presence of uncertainty had a marginal effect (5%) on minimum-delay conflict resolution performance, and windfavorable routes had no effect on detection and resolution metrics. Flight plan amendments and clearances were substantially reduced compared to today s operations. Top-of-descent prediction errors are the largest cause of failure indicating that better descent predictions are needed to reliably achieve fuel-efficient descent profiles in medium to heavy traffic. Improved conflict detections for climbing flights could enable substantially more continuous climbs to cruise altitude. Unlike today s Conflict Alert, tactical automation must alert when an altitude amendment is entered, but before the aircraft starts the maneuver. In every other failure case tactical automation prevented losses of separation. A real-time prototype trajectory trajectory-automation system is running now and could be made ready for operational testing at an en route

  10. Ground-based photometry of the 21-day Neptune HD 106315c

    Science.gov (United States)

    Lendl, M.; Ehrenreich, D.; Turner, O. D.; Bayliss, D.; Blanco-Cuaresma, S.; Giles, H.; Bouchy, F.; Marmier, M.; Udry, S.

    2017-07-01

    Space-based transit surveys such as K2 and the Transiting Exoplanets Survey Satellite (TESS) allow the detection of small transiting planets with orbital periods greater than 10 days. Few of these warm Neptunes are currently known around stars bright enough to allow for detailed follow-up observations dedicated to their atmospheric characterization. The 21-day period and 3.95 R⊕ planet HD 106315c has been discovered by K2 based on the observation of two of its transits. We observed HD 106315 using the 1.2 m Euler telescope equipped with the EulerCam camera on two occasions to confirm the transit using broadband photometry and refine the planetary period. Based on two observed transits of HD 106315c, we detect its 1 mmag transit and obtain a precise measurement of the planetary ephemerides, which are critical for planning further follow-up observations. We used the attained precision together with the predicted yield from the TESS mission to evaluate the potential for ground-based confirmation of Neptune-sized planets found by TESS. We find that one-meter class telescopes on the ground equipped with precise photometers could substantially contribute to the follow-up of 162 TESS candidates orbiting stars with magnitudes of V ≤ 14. Of these candidates, 74 planets orbit stars with V ≤ 12 and 12 planets orbit V ≤ 10, which makes them high-priority objects for atmospheric characterization with high-end instrumentation. The photometric time series data are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/603/L5

  11. Check Six Begins on the Ground: Responding to the Evolving Ground Threat to U.S. Air Force Bases.

    Science.gov (United States)

    1995-01-01

    V, Chicago, 111.: University of Chicago Press, 1953. Crichton -Stuart, Michael , G Patrol, London: William Kimber, 1958. Davin, D. M., Crete...base-defense operations. We wish to ex- press special thanks to Col Michael Rader, Lt Col Vevoris, Maj Peterson, Capt Angelosanto, and Capt Chris

  12. Ground-based Observations of the Solar Sources of Space Weather

    Science.gov (United States)

    Veronig, A. M.; Pötzi, W.

    2016-04-01

    Monitoring of the Sun and its activity is a task of growing importance in the frame of space weather research and awareness. Major space weather disturbances at Earth have their origin in energetic outbursts from the Sun: solar flares, coronal mass ejections and associated solar energetic particles. In this review we discuss the importance and complementarity of ground-based and space-based observations for space weather studies. The main focus is drawn on ground-based observations in the visible range of the spectrum, in particular in the diagnostically manifold Hα spectral line, which enables us to detect and study solar flares, filaments (prominences), filament (prominence) eruptions, and Moreton waves. Existing Hα networks such as the GONG and the Global High-Resolution Hα Network are discussed. As an example of solar observations from space weather research to operations, we present the system of real-time detection of Hα flares and filaments established at Kanzelhöhe Observatory (KSO; Austria) in the frame of the space weather segment of the ESA Space Situational Awareness programme (swe.ssa.esa.int). An evaluation of the system, which is continuously running since July 2013 is provided, covering an evaluation period of almost 2.5 years. During this period, KSO provided 3020 hours of real-time Hα observations at the ESA SWE portal. In total, 824 Hα flares were detected and classified by the real-time detection system, including 174 events of Hα importance class 1 and larger. For the total sample of events, 95 % of the automatically determined flare peak times lie within ±5 min of the values given in the official optical flares reports (by NOAA and KSO), and 76 % of the start times. The heliographic positions determined are better than ±5°. The probability of detection of flares of importance 1 or larger is 95 %, with a false alarm rate of 16 %. These numbers confirm the high potential of automatic flare detection and alerting from ground-based

  13. Control Method of Single-phase Inverter Based Grounding System in Distribution Networks

    DEFF Research Database (Denmark)

    Wang, Wen; Yan, L.; Zeng, X.

    2016-01-01

    The asymmetry of the inherent distributed capacitances causes the rise of neutral-to-ground voltage in ungrounded system or high resistance grounded system. Overvoltage may occur in resonant grounded system if Petersen coil is resonant with the distributed capacitances. Thus, the restraint of neu...... of the control method is presented in detail. Experimental results prove the effectiveness and novelty of the proposed grounding system and control method....

  14. Real-time threat evaluation in a ground based air defence environment

    Directory of Open Access Journals (Sweden)

    JN Roux

    2008-06-01

    Full Text Available In a military environment a ground based air defence operator is required to evaluate the tactical situation in real-time and protect Defended Assets (DAs on the ground against aerial threats by assigning available Weapon Systems (WSs to engage enemy aircraft. Since this aerial environment requires rapid operational planning and decision making in stress situations, the associated responsibilities are typically divided between a number of operators and computerized systems that aid these operators during the decision making processes. One such a Decision Support System (DSS, a threat evaluation and weapon assignment system, assigns threat values to aircraft (with respect to DAs in real-time and uses these values to propose possible engagements of observed enemy aircraft by anti-aircraft WSs. In this paper a design of the threat evaluation part of such a DSS is put forward. The design follows the structured approach suggested in [Roux JN & van Vuuren JH, 2007, Threat evaluation and weapon assignment decision support: A review of the state of the art, ORiON, 23(2, pp. 151-187], phasing in a suite of increasingly complex qualitative and quantitative model components as more (reliable data become available.

  15. Ground-Based Tests of Spacecraft Polymeric Materials under OXY-GEN Plasma-Beam

    Science.gov (United States)

    Chernik, Vladimir; Novikov, Lev; Gaidar, Anna

    2016-07-01

    Spacecraft LEO mission is accompanied by destruction of polymeric material surface under influence of atomic oxygen flow. Sources of molecular, plasma and ion beams are used for the accelerated ground-based tests of spacecraft materials. In the work application of oxygen plasma accelerator of a duoplasmatron type is described. Plasma particles have been accelerated up to average speed of 13-16 km/s. Influence of such beam on materials leads to more intensive destruction of polymers than in LEO. This fact allows to execute tests in the accelerated time scale by a method of an effective fluence. Special measures were given to decrease a concentration of both gaseous and electrode material impurities in the oxygen beam. In the work the results of simulative tests of spacecraft materials and experiments on LEO are considered. Comparison of plasma beam simulation with LEO data has shown conformity for structures of a number of polymeric materials. The relative erosion yields (normalized with respect to polyimide) of the tested materials are shown practically equal to those in LEO. The obtained results give grounds for using the plasma-generation mode with ion energies of 20-30 eV to accelerated testing of spacecraft materials for long -term LEO missions.

  16. Curvelet filter based prescreener for explosive hazard detection in hand-held ground penetrating radar

    Science.gov (United States)

    White, Julie L.; Anderson, Derek T.; Ball, John E.; Parker, Brian

    2016-05-01

    Explosive hazards, above and below ground, are a serious threat to civilians and soldiers. In an attempt to mitigate these threats, different forms of explosive hazard detection (EHD) exist; e.g., multi-sensor hand-held platforms, downward looking and forward looking vehicle mounted platforms, etc. Robust detection of these threats resides in the processing and fusion of different data from multiple sensing modalities, e.g., radar, infrared, electromagnetic induction (EMI), etc. Herein, we focus on a new energy-based prescreener in hand-held ground penetrating radar (GPR). First, we Curvelet filter B-scan signal data using either Reverse-Reconstruction followed by Enhancement (RRE) or selectivity with respect to wedge information in the Curvelet transform. Next, we aggregate the result of a bank of matched filters and run a size contrast filter with Bhattacharyya distance. Alarms are then combined using weighted mean shift clustering. Results are demonstrated in the context of receiver operating characteristics (ROC) curve performance on data from a U. S. Army test site that contains multiple target and clutter types, burial depths and times of the day.

  17. Forward modeling of seepage of reservoir dam based on ground penetrating radar

    Directory of Open Access Journals (Sweden)

    Xueli WU

    2017-08-01

    Full Text Available The risk of the reservoir dam seepage will bring the waste of water resources and the loss of life and property. The ground penetrating radar (GPR is designed as a daily inspection system of dams to improve the existing technology which can't determine the actual situation of the dam seepage tunnel coordinates. The finite difference time domain (FDTD is used to solve the Yee's grids discreatization in two-dimensional space, and its electromagnetic distribution equation is obtained as well. Based on the actual structure of reservoir dam foundation, the ideal model of air layer, concrete layer, clay layer and two water seepage holes is described in detail, and the concrete layer interference model with limestone interference point is established. The system architecture is implemented by using MATLAB, and the forward modeling is performed. The results indicate that ground penetrating radar can be used for deep target detection. Through comparing the detection spectrum of three kinds of frequency electromagnetic wave by changing the center frequency of the GPR electromagnetic wave of 50 MHz, 100 MHz and 200 MHz, it is concluded that the scanning result is more accurate at 100 MHz. At the same time, the simulation results of the interference model show that this method can be used for the detection of complex terrain.

  18. Hybrid onboard and ground based digital channelizer beam-forming for SATCOM interference mitigation and protection

    Science.gov (United States)

    Xiong, Wenhao; Wang, Gang; Tian, Xin; Pham, Khanh; Blasch, Erik; Chen, Genshe

    2016-05-01

    In this work, we propose a novel beam-forming power allocation method for a satellite communication (SATCOM) multiple-input multiple-output (MIMO) system to mitigate the co-channel interference (CCI) as well as limiting the signal leakage to the adversary users. In SATCOM systems, the beam-forming technique is a conventional way of avoiding interference, controlling the antenna beams, and mitigating undesired signals. We propose to use an advanced beam-forming technique which considers the number of independent channels used and transmitting power deployed to reduce and mitigate the unintentional interference effect. With certain quality of service (QoS) for the SATCOM system, independent channels components will be selected. It is desired to use less and stronger channel components when possible. On the other hand, considering that SATCOM systems often face the problem that adversary receiver detects the signal, a proposed power allocation method can efficiently reduce the received power at the adversary receiver. To reduce the computational burden on the transponder in order to minimize the size, mass, power consumption and delay for the satellite, we apply a hybrid onboard and ground based beam-forming design to distribute the calculation between the transponder and ground terminals. Also the digital channelizer beam-forming (DCB) technique is employed to achieve dynamic spatial control.

  19. A Ground-Based Validation System of Teleoperation for a Space Robot

    Directory of Open Access Journals (Sweden)

    Xueqian Wang

    2012-10-01

    Full Text Available Teleoperation of space robots is very important for future on‐orbit service. In order to assure the task is accomplished successfully, ground experiments are required to verify the function and validity of the teleoperation system before a space robot is launched. In this paper, a ground‐based validation subsystem is developed as a part of a teleoperation system. The subsystem is mainly composed of four parts: the input verification module, the onboard verification module, the dynamic and image workstation, and the communication simulator. The input verification module, consisting of hardware and software of the master, is used to verify the input ability. The onboard verification module, consisting of the same hardware and software as the onboard processor, is used to verify the processor’s computing ability and execution schedule. In addition, the dynamic and image workstation calculates the dynamic response of the space robot and target, and generates emulated camera images, including the hand‐eye cameras, global‐ vision camera and rendezvous camera. The communication simulator provides fidelity communication conditions, i.e., time delays and communication bandwidth. Lastly, we integrated a teleoperation system and conducted many experiments on the system. Experiment results show that the ground system is very useful for verified teleoperation technology.

  20. Ground and river water quality monitoring using a smartphone-based pH sensor

    Directory of Open Access Journals (Sweden)

    Sibasish Dutta

    2015-05-01

    Full Text Available We report here the working of a compact and handheld smartphone-based pH sensor for monitoring of ground and river water quality. Using simple laboratory optical components and the camera of the smartphone, we develop a compact spectrophotometer which is operational in the wavelength range of 400-700 nm and having spectral resolution of 0.305 nm/pixel for our equipment. The sensor measures variations in optical absorption band of pH sensitive dye sample in different pH solutions. The transmission image spectra through a transmission grating gets captured by the smartphone, and subsequently converted into intensity vs. wavelengths. Using the designed sensor, we measure water quality of ground water and river water from different locations in Assam and the results are found to be reliable when compared with the standard spectrophotometer tool. The overall cost involved for development of the sensor is relatively low. We envision that the designed sensing technique could emerge as an inexpensive, compact and portable pH sensor that would be useful for in-field applications.

  1. Ground and river water quality monitoring using a smartphone-based pH sensor

    Science.gov (United States)

    Dutta, Sibasish; Sarma, Dhrubajyoti; Nath, Pabitra

    2015-05-01

    We report here the working of a compact and handheld smartphone-based pH sensor for monitoring of ground and river water quality. Using simple laboratory optical components and the camera of the smartphone, we develop a compact spectrophotometer which is operational in the wavelength range of 400-700 nm and having spectral resolution of 0.305 nm/pixel for our equipment. The sensor measures variations in optical absorption band of pH sensitive dye sample in different pH solutions. The transmission image spectra through a transmission grating gets captured by the smartphone, and subsequently converted into intensity vs. wavelengths. Using the designed sensor, we measure water quality of ground water and river water from different locations in Assam and the results are found to be reliable when compared with the standard spectrophotometer tool. The overall cost involved for development of the sensor is relatively low. We envision that the designed sensing technique could emerge as an inexpensive, compact and portable pH sensor that would be useful for in-field applications.

  2. Method of forecasting seismic energy induced by longwall exploitation based on changes in ground subsidence

    Institute of Scientific and Technical Information of China (English)

    Violetta Sokoola Szewiola

    2011-01-01

    A method of forecasting total seismic energy induced by longwall exploitation,based on changes in ground subsidence,is presented in the form of a linear regression model with one with one independent variable.In the method,ground subsidence is described with a cross-section area of a subsidence trough Pw along a line of observations in the direction of an advancing longwall front,approximately along the axis of the Iongwall area.Total seismic energy is determined on the basis of seismic energy data of tremors induced by exploitation.The presentation consists of a detailed method and evaluation of its predictive ability for the area of longwall exploitation within the region of one of the coal mines in the Upper Silesian Coal Basin.This method can be used for forecasting the total seismic energy released by tremors within the area directly connected with the exploitation,in which the seismic activity induced by this exploitation occurs.The estimation of the parameters of the determined model should each time be carried out with investigations of the correctness of the model.The method cannot be applied when the number of recorded phenomena is small and when there is insufficient data to make it possible to calculate the index Pw.

  3. Probabilistic analysis of embankment slope stability in frozen ground regions based on random finite element method

    Institute of Scientific and Technical Information of China (English)

    Xi Chen; JianKun Liu; Nan Xie; HuiJing Sun

    2015-01-01

    Prediction on the coupled thermal-hydraulic fields of embankment and cutting slopes is essential to the assessment on evolution of melting zone and natural permafrost table, which is usually a key factor for permafrost embankment design in frozen ground regions. The prediction may be further complicated due to the inherent uncertainties of material properties. Hence, stochastic analyses should be conducted. Firstly, Karhunen-Loeve expansion is applied to attain the random fields for hydraulic and thermal conductions. Next, the mixed-form modified Richards equation for mass transfer (i.e., mass equation) and the heat transport equation for heat transient flow in a variably saturated frozen soil are combined into one equation with temperature unknown. Furthermore, the finite element formulation for the coupled thermal-hydraulic fields is derived. Based on the random fields, the stochastic finite element analyses on stability of embankment are carried out. Numerical results show that stochastic analyses of embankment stability may provide a more rational picture for the distribution of factors of safety (FOS), which is definitely useful for embankment design in frozen ground regions.

  4. Solidification kinetics of a Cu-Zr alloy: ground-based and microgravity experiments

    Science.gov (United States)

    Galenko, P. K.; Hanke, R.; Paul, P.; Koch, S.; Rettenmayr, M.; Gegner, J.; Herlach, D. M.; Dreier, W.; Kharanzhevski, E. V.

    2017-04-01

    Experimental and theoretical results obtained in the MULTIPHAS-project (ESA-European Space Agency and DLR-German Aerospace Center) are critically discussed regarding solidification kinetics of congruently melting and glass forming Cu50Zr50 alloy samples. The samples are investigated during solidification using a containerless technique in the Electromagnetic Levitation Facility [1]. Applying elaborated methodologies for ground-based and microgravity experimental investigations [2], the kinetics of primary dendritic solidification is quantitatively evaluated. Electromagnetic Levitator in microgravity (parabolic flights and on board of the International Space Station) and Electrostatic Levitator on Ground are employed. The solidification kinetics is determined using a high-speed camera and applying two evaluation methods: “Frame by Frame” (FFM) and “First Frame - Last Frame” (FLM). In the theoretical interpretation of the solidification experiments, special attention is given to the behavior of the cluster structure in Cu50Zr50 samples with the increase of undercooling. Experimental results on solidification kinetics are interpreted using a theoretical model of diffusion controlled dendrite growth.

  5. Application of Fault Location Mode Based on Travelling Waves for Neutral Non-effective Grounding Systems

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    <正>Fault location for distribution feeders short circuit especially single-phase grounding fault is an important task in distribution system with non-effectively grounded neutral.Fault location mode for distribution feeders using fault generated current and voltage transient traveling waves was investigated.The characteristics of transient traveling waves resulted from each short circuit fault and their transmission disciplinarian in distribution feeders are analyzed.This paper proposed that double end travelling waves theory which measures arriving time of fault initiated surge at both ends of the monitored line is fit for distribution feeders but single end traveling waves theory not.According to different distribution feeders,on the basis of analyzing original traveling waves reflection rule in line terminal, Current-voltage mode,voltage-voltage mode and current-current mode for fault location based on traveling waves are proposed and aerial mode component of original traveling waves is used to realize fault location.Experimental test verify the feasibility and correctness of the proposed method.

  6. MICROSTRUCTURE, MINERALOGY AND PHYSICAL PROPERTIES OF GROUND FLY ASH BASED GEOPOLYMERS

    Directory of Open Access Journals (Sweden)

    Ferenc Madai

    2015-03-01

    Full Text Available This paper is focused on the utilization of deposited fly ash as a main component of geopolymer. After determination of particle size distribution, moisture content, real and bulk density and specific surface area of the raw fly ash, mechanical activation was performed by laboratory scale ball mill. This step is introduced for improving the reactivity of raw material. Then test specimens were produced by geopoliomerisation using a caustic spent liquor (NaOH. Compressive strength was determined on cilindrical specimens. Finally, samples of the ground fly ash based geopolymer specimens were analyzed by X-ray diffraction, optical and scanning electron microscopy. Results prove that geopolymer production with proper strength from the investigated F-type deposited fly ash is possible. The uniaxial compressive strength of obtained composites strongly depends on the fineness of the ground fly ash. XRD results show that comparing the crystalline components for different geopolymer samples, zeolite-A appears and its amount increases gradually from 0T sample till 30T and then decreases for 60T sample. The same trend holds for sodalite type structure phases, however its amount is much lower than for zeolite-A. SEM+EDS investigation revealed that Na-content is elevated in the interstitial fine-grained matrix, especially for the 30T sample when highest strength was observed. Si and Al are abundant mainly in anhedral and spherical grains and in rarely occurring grains resembling some crystal shape.

  7. Reaching for the stars - New developments in ground-based astronomy

    CERN Document Server

    CERN. Geneva

    2015-01-01

    I will briefly review the state-of-the-art in ground-based astronomy - both on the telescope side and the instrument side. Interesting parallels can be drawn in cost, construction and operations with the particle physics facilities. I will then present some recent results in the two hottest topics in astronomy, driving the requests for more advanced facilities: exoplanets and the hunt for life beyond the solar system (calling for Extremely Large Telescope); and cosmology and the understanding of dark energy (calling for large survey telescopes). This will lead to a description of the latest telescope project developments on the ground: the on-going construction of the Large Synoptic Telescope on a quest to better understand dark energy, and the start of the construction of three Extremely Large Telescopes by European and US-led international consortia, hoping to find life on planets around nearby stars.   ATS Seminars Organisers: H. Burkhardt (BE), M. Modena (TE), T. Stora (EN) Coffee / tea will ...

  8. Spent coffee grounds-based activated carbon preparation for sequestering of malachite green

    Science.gov (United States)

    Lim, Jun-Wei; Lam, Keat-Ying; Bashir, Mohammed J. K.; Yeong, Yin-Fong; Lam, Man-Kee; Ho, Yeek-Chia

    2016-11-01

    The key of reported work was to optimize the fabricating factors of spent coffee grounds-based activated carbon (SCG-bAC) used to sequester Malachite Green (MG) form aqueous solution via adsorption process. The fabricating factors of impregnation ratio with ortho-phosphoric acid, activation temperature and activation time were simultaneously optimized by central composite design (CCD) of response surface methodology (RSM) targeting on maximum removal of MG. At the optimum condition, 96.3% of MG was successfully removed by SCG-bAC at the impregnation ratio with ortho-phosphoric acid of 0.50, activation temperature of 554°C and activation time of 31.4 min. Statistical model that could predict the MG removal percentage was also derived and had been statistically confirmed to be significant. Subsequently, the MG adsorption equilibrium data was found well-fitted to Langmuir isotherm model, indicating the predominance of monolayer adsorption of MG on SCG-bAC surface. To conclude, the findings from the this study unveil the potential of spent coffee grounds as an alternative precursor in fabricating low-cost AC for the treatment of wastewater loaded with MG pollutant.

  9. Coupling Fine-Scale Root and Canopy Structure Using Ground-Based Remote Sensing

    Directory of Open Access Journals (Sweden)

    Brady S. Hardiman

    2017-02-01

    Full Text Available Ecosystem physical structure, defined by the quantity and spatial distribution of biomass, influences a range of ecosystem functions. Remote sensing tools permit the non-destructive characterization of canopy and root features, potentially providing opportunities to link above- and belowground structure at fine spatial resolution in functionally meaningful ways. To test this possibility, we employed ground-based portable canopy LiDAR (PCL and ground penetrating radar (GPR along co-located transects in forested sites spanning multiple stages of ecosystem development and, consequently, of structural complexity. We examined canopy and root structural data for coherence (i.e., correlation in the frequency of spatial variation at multiple spatial scales ≤10 m within each site using wavelet analysis. Forest sites varied substantially in vertical canopy and root structure, with leaf area index and root mass more becoming even vertically as forests aged. In all sites, above- and belowground structure, characterized as mean maximum canopy height and root mass, exhibited significant coherence at a scale of 3.5–4 m, and results suggest that the scale of coherence may increase with stand age. Our findings demonstrate that canopy and root structure are linked at characteristic spatial scales, which provides the basis to optimize scales of observation. Our study highlights the potential, and limitations, for fusing LiDAR and radar technologies to quantitatively couple above- and belowground ecosystem structure.

  10. Enhanced static ground power unit based on flying capacitor based h-bridge hybrid active-neutral-point-clamped converter

    DEFF Research Database (Denmark)

    Abarzadeh, Mostafa; Madadi Kojabadi, Hossein; Deng, Fujin

    2016-01-01

    Static power converters have various applications, such as static ground power units (GPUs) for airplanes. This study proposes a new configuration of a static GPU based on a novel nine-level flying capacitor h-bridge active-neutral-point-clamped (FCHB_ANPC) converter. The main advantages...... improvement in GPU dynamic performances. This progress is achieved by utilising the proposed FCHB converter to an ANPC converter and using the suggested modulation method. This leads to diminish the size and cost and enhance the feasibility and reliability of the converter. Applying the proposed modulation...

  11. Validation of middle atmospheric campaign-based water vapour measured by the ground-based microwave radiometer MIAWARA-C

    Directory of Open Access Journals (Sweden)

    B. Tschanz

    2013-02-01

    Full Text Available Middle atmospheric water vapour can be used as a tracer for dynamical processes. It is mainly measured by satellite instruments and ground-based microwave radiometers. Ground-based instruments capable of measuring middle atmospheric water vapour are sparse but valuable as they complement satellite measurements, are relatively easy to maintain and have a long lifetime. MIAWARA-C is a ground-based microwave radiometer for middle atmospheric water vapour designed for use on measurement campaigns for both atmospheric case studies and instrument intercomparisons. MIAWARA-C's retrieval version 1.1 (v1.1 is set up in a way to provide a consistent data set even if the instrument is operated from different locations on a campaign basis. The sensitive altitude range for v1.1 extends from 4 hPa (37 km to 0.017 hPa (75 km. MIAWARA-C measures two polarisations of the incident radiation in separate receiver channels and can therefore provide two independent measurements of the same air mass. The standard deviation of the difference between the profiles obtained from the two polarisations is in excellent agreement with the estimated random error of v1.1. In this paper, the quality of v1.1 data is assessed during two measurement campaigns: (1 five months of measurements in the Arctic (Sodankylä, 67.37° N/26.63° E and (2 nine months of measurements at mid-latitudes (Zimmerwald, 46.88° N/7.46° E. For both campaigns MIAWARA-C's profiles are compared to measurements from the satellite experiments Aura MLS and MIPAS. In addition, comparisons to ACE-FTS and SOFIE are presented for the Arctic and to the ground-based radiometer MIAWARA for the mid-latitudinal campaign. In general all intercomparisons show high correlation coefficients, above 0.5 at altitudes above 45 km, confirming the ability of MIAWARA-C to monitor temporal variations on the order of days. The biases are generally below 10% and within the estimated systematic uncertainty of MIAWARA-C. No

  12. Ground-based RGB imaging to determine the leaf water potential of potato plants

    Science.gov (United States)

    Zakaluk, Robert F.

    The determination of plant water status from leaf water potential (Psi L) data obtained by conventional methods is impractical for meeting real time irrigation monitoring requirements. This research, undertaken first, in a greenhouse and then in the field, examined the use of artificial neural network (ANN) modeling of RGB (red green blue) images, captured by a ground-based, five mega pixel digital camera, to predict the leaf water potential of potato (Solanum tuberosum L). The greenhouse study examined cv. Russet Burbank, while the field study examined cv. Sangre. The protocol was similar in both studies: (1) images were acquired over different soil nitrate (N) and volumetric water content levels, (2) images were radiometrically calibrated, (3) green foliage was classified and extracted from the images, and (4) image transformations, and vegetation indices were calculated and transformed using principal components analysis (PCA). The findings from both studies were similar: (1) the R and G bands were more important than the B image band in the classification of green leaf pigment, (2) soil N showed an inverse linear relationship against leaf reflectance in the G image band, (3) the ANN model input neuron weights with more separation between soil N and PsiL were more important than other input neurons in predicting PsiL, and (4) the measured and predicted PsiL validation datasets were normally distributed with equal variances and means that were not significantly different. Based on these research findings, the ground-based digital camera proved to be an adequate sensor for image acquisition and a practical tool for acquiring data for predicting the PsiL of potato plants. Keywords: nitrogen, IHS transformation, chromaticity transformation, principal components, vegetation indices, remote sensing, artificial neural network, digital camera.

  13. Detection and quantification of localized groundwater inflow in small streams using ground-based infrared thermography

    Science.gov (United States)

    Schuetz, Tobias; Weiler, Markus

    2010-05-01

    Localized groundwater (GW) inflow into small streams can be a major source of runoff during low flow periods in headwater catchments. The localization and determination of the fraction of runoff corresponding to a certain area may give insights into aquifer type, flow processes, the composition of base-flow concerning the spatial distribution of catchment storage and water quality issues. Though GW temperature has a small amplitude during the year compared to surface water, a significant temperature difference between stream water and groundwater can be expected in summer and winter. As the technical development of infrared thermography is progressing (the spatial resolution of infrared camera systems is increasing and the measuring error is decreasing) we tested ground based infrared thermography as a non-invasive and remote applicable method to detect and quantify GW entries in small streams during baseflow periods (INFRATEC). In addition, water temperature and electric conductivity of the groundwater entering the stream and of the stream water up- and downstream of localized GW inflow were measured with temperature and EC sensors. Though the zones of complete mixing were identified, point measurements and surface radiation temperatures were taken from the same areas. Discharge measurements were conducted using the salt dilution method with continuous injection. End-member mixing calculations were done using the measured EC and water temperature data and compared to the results of mixing calculations of observed water surface radiation temperatures. The discharge observations were used to validate the fraction calculations. Calculated GW entries using thermogramms had comparable deviations from the measured runoff fractions to those from direct temperature and EC measurements. This leads to the conclusion that the use of ground-based infrared thermography for the detection and quantification of localized groundwater inflows into small streams is a valuable and

  14. Characterizing the Vertical Distribution of Aerosols using Ground-based Multiwavelength Lidar Data

    Science.gov (United States)

    Ferrare, R. A.; Thorsen, T. J.; Clayton, M.; Mueller, D.; Chemyakin, E.; Burton, S. P.; Goldsmith, J.; Holz, R.; Kuehn, R.; Eloranta, E. W.; Marais, W.; Newsom, R. K.; Liu, X.; Sawamura, P.; Holben, B. N.; Hostetler, C. A.

    2016-12-01

    Observations of aerosol optical and microphysical properties are critical for developing and evaluating aerosol transport model parameterizations and assessing global aerosol-radiation impacts on climate. During the Combined HSRL And Raman lidar Measurement Study (CHARMS), we investigated the synergistic use of ground-based Raman lidar and High Spectral Resolution Lidar (HSRL) measurements to retrieve aerosol properties aloft. Continuous (24/7) operation of these co-located lidars during the ten-week CHARMS mission (mid-July through September 2015) allowed the acquisition of a unique, multiwavelength ground-based lidar dataset for studying aerosol properties above the Southern Great Plains (SGP) site. The ARM Raman lidar measured profiles of aerosol backscatter, extinction and depolarization at 355 nm as well as profiles of water vapor mixing ratio and temperature. The University of Wisconsin HSRL simultaneously measured profiles of aerosol backscatter, extinction and depolarization at 532 nm and aerosol backscatter at 1064 nm. Recent advances in both lidar retrieval theory and algorithm development demonstrate that vertically-resolved retrievals using such multiwavelength lidar measurements of aerosol backscatter and extinction can help constrain both the aerosol optical (e.g. complex refractive index, scattering, etc.) and microphysical properties (e.g. effective radius, concentrations) as well as provide qualitative aerosol classification. Based on this work, the NASA Langley Research Center (LaRC) HSRL group developed automated algorithms for classifying and retrieving aerosol optical and microphysical properties, demonstrated these retrievals using data from the unique NASA/LaRC airborne multiwavelength HSRL-2 system, and validated the results using coincident airborne in situ data. We apply these algorithms to the CHARMS multiwavelength (Raman+HSRL) lidar dataset to retrieve aerosol properties above the SGP site. We present some profiles of aerosol effective

  15. Ground-based imaging remote sensing of ice clouds: uncertainties caused by sensor, method and atmosphere

    Science.gov (United States)

    Zinner, Tobias; Hausmann, Petra; Ewald, Florian; Bugliaro, Luca; Emde, Claudia; Mayer, Bernhard

    2016-09-01

    In this study a method is introduced for the retrieval of optical thickness and effective particle size of ice clouds over a wide range of optical thickness from ground-based transmitted radiance measurements. Low optical thickness of cirrus clouds and their complex microphysics present a challenge for cloud remote sensing. In transmittance, the relationship between optical depth and radiance is ambiguous. To resolve this ambiguity the retrieval utilizes the spectral slope of radiance between 485 and 560 nm in addition to the commonly employed combination of a visible and a short-wave infrared wavelength.An extensive test of retrieval sensitivity was conducted using synthetic test spectra in which all parameters introducing uncertainty into the retrieval were varied systematically: ice crystal habit and aerosol properties, instrument noise, calibration uncertainty and the interpolation in the lookup table required by the retrieval process. The most important source of errors identified are uncertainties due to habit assumption: Averaged over all test spectra, systematic biases in the effective radius retrieval of several micrometre can arise. The statistical uncertainties of any individual retrieval can easily exceed 10 µm. Optical thickness biases are mostly below 1, while statistical uncertainties are in the range of 1 to 2.5.For demonstration and comparison to satellite data the retrieval is applied to observations by the Munich hyperspectral imager specMACS (spectrometer of the Munich Aerosol and Cloud Scanner) at the Schneefernerhaus observatory (2650 m a.s.l.) during the ACRIDICON-Zugspitze campaign in September and October 2012. Results are compared to MODIS and SEVIRI satellite-based cirrus retrievals (ACRIDICON - Aerosol, Cloud, Precipitation, and Radiation Interactions and Dynamics of Convective Cloud Systems; MODIS - Moderate Resolution Imaging Spectroradiometer; SEVIRI - Spinning Enhanced Visible and Infrared Imager). Considering the identified

  16. Mixed-field GCR Simulations for Radiobiological Research Using Ground Based Accelerators

    Science.gov (United States)

    Kim, Myung-Hee Y.; Rusek, Adam; Cucinotta, Francis A.

    2014-01-01

    Space radiation is comprised of a large number of particle types and energies, which have differential ionization power from high energy protons to high charge and energy (HZE) particles and secondary neutrons produced by galactic cosmic rays (GCR). Ground based accelerators such as the NASA Space Radiation Laboratory (NSRL) at Brookhaven National Laboratory (BNL) are used to simulate space radiation for radiobiology research and dosimetry, electronics parts, and shielding testing using mono-energetic beams for single ion species. As a tool to support research on new risk assessment models, we have developed a stochastic model of heavy ion beams and space radiation effects, the GCR Event-based Risk Model computer code (GERMcode). For radiobiological research on mixed-field space radiation, a new GCR simulator at NSRL is proposed. The NSRL-GCR simulator, which implements the rapid switching mode and the higher energy beam extraction to 1.5 GeV/u, can integrate multiple ions into a single simulation to create GCR Z-spectrum in major energy bins. After considering the GCR environment and energy limitations of NSRL, a GCR reference field is proposed after extensive simulation studies using the GERMcode. The GCR reference field is shown to reproduce the Z and LET spectra of GCR behind shielding within 20% accuracy compared to simulated full GCR environments behind shielding. A major challenge for space radiobiology research is to consider chronic GCR exposure of up to 3-years in relation to simulations with cell and animal models of human risks. We discuss possible approaches to map important biological time scales in experimental models using ground-based simulation with extended exposure of up to a few weeks and fractionation approaches at a GCR simulator.

  17. Ground-based Light Curves Two Pluto Days Before the New Horizons Passage

    Science.gov (United States)

    Bosh, A. S.; Pasachoff, J. M.; Babcock, B. A.; Durst, R. F.; Seeger, C. H.; Levine, S. E.; Abe, F.; Suzuki, D.; Nagakane, M.; Sickafoose, A. A.; Person, M. J.; Zuluaga, C.; Kosiarek, M. R.

    2015-12-01

    We observed the occultation of a 12th magnitude star, one of the two brightest occultation stars ever in our dozen years of continual monitoring of Pluto's atmosphere through such studies, on 29 June 2015 UTC. At Canterbury University's Mt. John University Observatory on the south island of New Zealand, in clear sky, we used our POETS frame-transfer CCD at 10 Hz with GPS timing on the 1-m McLellan telescope as well as an infrared camera on an 0.6-m telescope and three-color photometry at a slower cadence on a second 0.6-m telescope. The light curves show a central flash, indicating that we were close to the center of the occultation path, and allowing us to explore Pluto's atmosphere lower than usual. The light curves show that Pluto's atmosphere remained robust. Observations from 0.5- and 0.4-m telescopes at the Auckland Observatory gave the first half of the occultation before clouds came in. We coordinated our observations with aircraft observations with NASA's Stratospheric Observatory for Infrared Astronomy (SOFIA) and its High Speed Imaging Photometer for Occultations (HIPO). Our ground-based and airborne stellar-occultation effort came only just over two weeks of Earth days and two Pluto days (based on Pluto's rotational period) before the flyby of NASA's New Horizons spacecraft, meaning that the mission's exquisite snapshot of Pluto's atmosphere can be placed in the context of our series of ground-based occultation observations carried out on a regular basis since 2002 following a first Pluto occultation observed in 1988 from aloft. Our observations were supported by NASA Planetary Astronomy grants NNX12AJ29G to Williams College, NNX15AJ82G to Lowell Observatory, and NNX10AB27G to MIT, and by the National Research Foundation of South Africa. We thank Alan Gilmore, Pam Kilmartin, Robert Lucas, Paul Tristam, and Carolle Varughese for assistance at Mt. John.

  18. Network operability of ground-based microwave radiometers: Calibration and standardization efforts

    Science.gov (United States)

    Pospichal, Bernhard; Löhnert, Ulrich; Küchler, Nils; Czekala, Harald

    2017-04-01

    Ground-based microwave radiometers (MWR) are already widely used by national weather services and research institutions all around the world. Most of the instruments operate continuously and are beginning to be implemented into data assimilation for atmospheric models. Especially their potential for continuously observing boundary-layer temperature profiles as well as integrated water vapor and cloud liquid water path makes them valuable for improving short-term weather forecasts. However until now, most MWR have been operated as stand-alone instruments. In order to benefit from a network of these instruments, standardization of calibration, operation and data format is necessary. In the frame of TOPROF (COST Action ES1303) several efforts have been undertaken, such as uncertainty and bias assessment, or calibration intercomparison campaigns. The goal was to establish protocols for providing quality controlled (QC) MWR data and their uncertainties. To this end, standardized calibration procedures for MWR have been developed and recommendations for radiometer users compiled. Based on the results of the TOPROF campaigns, a new, high-accuracy liquid-nitrogen calibration load has been introduced for MWR manufactured by Radiometer Physics GmbH (RPG). The new load improves the accuracy of the measurements considerably and will lead to even more reliable atmospheric observations. Next to the recommendations for set-up, calibration and operation of ground-based MWR within a future network, we will present homogenized methods to determine the accuracy of a running calibration as well as means for automatic data quality control. This sets the stage for the planned microwave calibration center at JOYCE (Jülich Observatory for Cloud Evolution), which will be shortly introduced.

  19. Navigating the Return Trip from the Moon Using Earth-Based Ground Tracking and GPS

    Science.gov (United States)

    Berry, Kevin; Carpenter, Russell; Moreau, Michael C.; Lee, Taesul; Holt, Gregg N.

    2009-01-01

    NASA s Constellation Program is planning a human return to the Moon late in the next decade. From a navigation perspective, one of the most critical phases of a lunar mission is the series of burns performed to leave lunar orbit, insert onto a trans-Earth trajectory, and target a precise re-entry corridor in the Earth s atmosphere. A study was conducted to examine sensitivity of the navigation performance during this phase of the mission to the type and availability of tracking data from Earth-based ground stations, and the sensitivity to key error sources. This study also investigated whether GPS measurements could be used to augment Earth-based tracking data, and how far from the Earth GPS measurements would be useful. The ability to track and utilize weak GPS signals transmitted across the limb of the Earth is highly dependent on the configuration and sensitivity of the GPS receiver being used. For this study three GPS configurations were considered: a "standard" GPS receiver with zero dB antenna gain, a "weak signal" GPS receiver with zero dB antenna gain, and a "weak signal" GPS receiver with an Earth-pointing direction antenna (providing 10 dB additional gain). The analysis indicates that with proper selection and configuration of the GPS receiver on the Orion spacecraft, GPS can potentially improve navigation performance during the critical final phases of flight prior to Earth atmospheric entry interface, and may reduce reliance on two-way range tracking from Earth-based ground stations.

  20. MetaSensing's FastGBSAR: ground based radar for deformation monitoring

    Science.gov (United States)

    Rödelsperger, Sabine; Meta, Adriano

    2014-10-01

    The continuous monitoring of ground deformation and structural movement has become an important task in engineering. MetaSensing introduces a novel sensor system, the Fast Ground Based Synthetic Aperture Radar (FastGBSAR), based on innovative technologies that have already been successfully applied to airborne SAR applications. The FastGBSAR allows the remote sensing of deformations of a slope or infrastructure from up to a distance of 4 km. The FastGBSAR can be setup in two different configurations: in Real Aperture Radar (RAR) mode it is capable of accurately measuring displacements along a linear range profile, ideal for monitoring vibrations of structures like bridges and towers (displacement accuracy up to 0.01 mm). Modal parameters can be determined within half an hour. Alternatively, in Synthetic Aperture Radar (SAR) configuration it produces two-dimensional displacement images with an acquisition time of less than 5 seconds, ideal for monitoring areal structures like dams, landslides and open pit mines (displacement accuracy up to 0.1 mm). The MetaSensing FastGBSAR is the first ground based SAR instrument on the market able to produce two-dimensional deformation maps with this high acquisition rate. By that, deformation time series with a high temporal and spatial resolution can be generated, giving detailed information useful to determine the deformation mechanisms involved and eventually to predict an incoming failure. The system is fully portable and can be quickly installed on bedrock or a basement. The data acquisition and processing can be fully automated leading to a low effort in instrument operation and maintenance. Due to the short acquisition time of FastGBSAR, the coherence between two acquisitions is very high and the phase unwrapping is simplified enormously. This yields a high density of resolution cells with good quality and high reliability of the acquired deformations. The deformation maps can directly be used as input into an Early

  1. Aerosol Single Scattering Albedo retrieved from ground-based measurements in the UV-visible

    Directory of Open Access Journals (Sweden)

    V. Buchard

    2010-07-01

    Full Text Available Estimates of Aerosol Single Scattering Albedo (SSA from ground-based spectral measurements in the UV-visible are conducted at Villeneuve d'Ascq (VdA in France. In order to estimate this parameter, measurements of global and diffuse UV-visible solar irradiances performed under cloud-free conditions since 2003 with a spectroradiometer operated by the Laboratoire d'Optique Atmosphérique (LOA are used. The technique consists in comparing the measured irradiance values to modelled irradiances computed for various SSA. The retrieval is restricted to the 330–450 nm range to avoid ozone influence.

    For validation purpose, the retrieved values of SSA at 440 nm are compared to the ones obtained from sunphotometer measurements of the AERONET/PHOTONS network available on the LOA site. The results are rather satisfying: in 2003 and 2005–2006 the Root Mean Square (RMS of the differences are about 0.05, these values are within the uncertainty domain of retrieval of both products. Distinction between days characterized by different aerosol content, by means of the aerosol optical thickness (AOT retrieved from ground-based measurements at the same wavelength, shows that the comparisons between both products are better when AOT are higher. Indeed in case AOT are greater than 0.2, the RMS is 0.027 in 2003 and 0.035 in 2005–2006. The SSA estimated at 340 and 380 nm from ground-based spectra are also studied, though no validation can be carried out with sunphotometer data (440 nm is the shortest wavelength at which the SSA is provided by the network. The good comparisons observed at 440 nm can let assume that the SSA retrieved from spectroradiometer measurements at the two other wavelengths are also obtained with a good confidence level. Thus these values in the UV range can be used to complete aerosol data provided by AERONET/PHOTONS at VdA. Moreover they can be used for a best knowledge of the aerosol absorption that is necessary to quantify the

  2. Investigation of Rainfall Characteristics Using TRMM PR and Ground Based Radar

    Science.gov (United States)

    Dolan, B.; Lang, T. J.; Nesbitt, S. W.; Cifelli, R.; Rutledge, S. A.

    2011-12-01

    Despite relatively good agreement between reflectivity profiles, comparisons of rainfall statistics derived from TRMM Precipitation Radar (PR) deviate from ground-based radar (GR) observations in various field locations across the globe. TRMM PR rain rate probability distribution functions underestimate the occurrence of high rain rates (> 80 mm hr-1) compared with similar ground-based statistics, and similarly, GR distributes the total rain volume over a larger range of rain rates. Analysis of ten years of TRMM data over three field sites has shown that the greatest disagreements occur in the most intense convection, such as over land and during the east and break wind regimes over the Amazon and Australia, respectively. These differences are investigated further in this study. Ten years of TRMM PR data are analyzed in conjunction with data collected during two field experiments involving the NCAR S-Pol radar. S-Pol was deployed in Brazil in the Amazon during TRMM LBA in 1998-1999 and near Mazatlan, Mexico as part of the North American Monsoon Experiment (NAME) in 2004. Additionally, multiple years of data from the Australian Bureau of Meteorology CPOL radar located in Darwin, Australia, are examined to extend the robustness of the GR observations beyond the relatively short field campaigns. Polarimetric data collected by the two radars are used to characterize the differences between TRMM PR and GR observations as a function of bulk hydrometeor type. For example, profiles with significant graupel, as identified by GR, are analyzed to investigate the role of mixed phase in the PR retrievals. The vertical variability of D0 is examined as a function of reflectivity and related to the underlying microphysical conditions using the polarimetric data provided by the GR observations. Spatial variability of D0 is also explored by correlating D0 values derived from GR at different heights. Several significant changes were made to the TRMM processing algorithms in the

  3. Suborbital Reusable Launch Vehicles as an Opportunity to Consolidate and Calibrate Ground Based and Satellite Instruments

    Science.gov (United States)

    Papadopoulos, K.

    2014-12-01

    XCOR Aerospace, a commercial space company, is planning to provide frequent, low cost access to near-Earth space on the Lynx suborbital Reusable Launch Vehicle (sRLV). Measurements in the external vacuum environment can be made and can launch from most runways on a limited lead time. Lynx can operate as a platform to perform suborbital in situ measurements and remote sensing to supplement models and simulations with new data points. These measurements can serve as a quantitative link to existing instruments and be used as a basis to calibrate detectors on spacecraft. Easier access to suborbital data can improve the longevity and cohesiveness of spacecraft and ground-based resources. A study of how these measurements can be made on Lynx sRLV will be presented. At the boundary between terrestrial and space weather, measurements from instruments on Lynx can help develop algorithms to optimize the consolidation of ground and satellite based data as well as assimilate global models with new data points. For example, current tides and the equatorial electrojet, essential to understanding the Thermosphere-Ionosphere system, can be measured in situ frequently and on short notice. Furthermore, a negative-ion spectrometer and a Faraday cup, can take measurements of the D-region ion composition. A differential GPS receiver can infer the spatial gradient of ionospheric electron density. Instruments and optics on spacecraft degrade over time, leading to calibration drift. Lynx can be a cost effective platform for deploying a reference instrument to calibrate satellites with a frequent and fast turnaround and a successful return of the instrument. A calibrated reference instrument on Lynx can make collocated observations as another instrument and corrections are made for the latter, thus ensuring data consistency and mission longevity. Aboard a sRLV, atmospheric conditions that distort remotely sensed data (ground and spacecraft based) can be measured in situ. Moreover, an

  4. Ground-based acoustic parametric generator impact on the atmosphere and ionosphere in an active experiment

    Science.gov (United States)

    Rapoport, Yuriy G.; Cheremnykh, Oleg K.; Koshovy, Volodymyr V.; Melnik, Mykola O.; Ivantyshyn, Oleh L.; Nogach, Roman T.; Selivanov, Yuriy A.; Grimalsky, Vladimir V.; Mezentsev, Valentyn P.; Karataeva, Larysa M.; Ivchenko, Vasyl. M.; Milinevsky, Gennadi P.; Fedun, Viktor N.; Tkachenko, Eugen N.

    2017-01-01

    We develop theoretical basics of active experiments with two beams of acoustic waves, radiated by a ground-based sound generator. These beams are transformed into atmospheric acoustic gravity waves (AGWs), which have parameters that enable them to penetrate to the altitudes of the ionospheric E and F regions where they influence the electron concentration of the ionosphere. Acoustic waves are generated by the ground-based parametric sound generator (PSG) at the two close frequencies. The main idea of the experiment is to design the output parameters of the PSG to build a cascade scheme of nonlinear wave frequency downshift transformations to provide the necessary conditions for their vertical propagation and to enable penetration to ionospheric altitudes. The PSG generates sound waves (SWs) with frequencies f1 = 600 and f2 = 625 Hz and large amplitudes (100-420 m s-1). Each of these waves is modulated with the frequency of 0.016 Hz. The novelty of the proposed analytical-numerical model is due to simultaneous accounting for nonlinearity, diffraction, losses, and dispersion and inclusion of the two-stage transformation (1) of the initial acoustic waves to the acoustic wave with the difference frequency Δf = f2 - f1 in the altitude ranges 0-0.1 km, in the strongly nonlinear regime, and (2) of the acoustic wave with the difference frequency to atmospheric acoustic gravity waves with the modulational frequency in the altitude ranges 0.1-20 km, which then reach the altitudes of the ionospheric E and F regions, in a practically linear regime. AGWs, nonlinearly transformed from the sound waves, launched by the two-frequency ground-based sound generator can increase the transparency of the ionosphere for the electromagnetic waves in HF (MHz) and VLF (kHz) ranges. The developed theoretical model can be used for interpreting an active experiment that includes the PSG impact on the atmosphere-ionosphere system, measurements of electromagnetic and acoustic fields, study of

  5. Overview and Initial Results from the DEEPWAVE Airborne and Ground-Based Measurement Program

    Science.gov (United States)

    Fritts, D. C.

    2015-12-01

    The deep-propagating gravity wave experiment (DEEPWAVE) was performed on and over New Zealand, the Tasman Sea, and the Southern Ocean with core airborne measurements extending from 5 June to 21 July 2014 and supporting ground-based measurements spanning a longer interval. The NSF/NCAR GV employed standard flight-level measurements and new airborne lidar and imaging measurements of gravity waves (GWs) from sources at lower altitudes throughout the stratosphere and into the mesosphere and lower thermosphere (MLT). The new GV lidars included a Rayleigh lidar measuring atmospheric density and temperature from ~20-60 km and a sodium resonance lidar measuring sodium density and temperature at ~75-105 km. An airborne Advanced Mesosphere Temperature Mapper (AMTM) and two IR "wing" cameras imaged the OH airglow temperature and/or intensity fields extending ~900 km across the GV flight track. The DLR Falcon was equipped with its standard flight-level instruments and an aerosol Doppler lidar measuring radial winds below the Falcon. DEEPWAVE also included extensive ground-based measurements in New Zealand, Tasmania, and Southern Ocean Islands. DEEPWAVE performed 26 GV flights and 13 Falcon flights, and ground-based measurements occurred whether or not the aircraft were flying. Collectively, many diverse cases of GW forcing, propagation, refraction, and dissipation spanning altitudes of 0-100 km were observed. Examples include strong mountain wave (MW) forcing and breaking in the lower and middle stratosphere, weak MW forcing yielding MW penetration into the MLT having very large amplitudes and momentum fluxes, MW scales at higher altitudes ranging from ~10-250 km, large-scale trailing waves from orography refracting into the polar vortex and extending to high altitudes, GW generation by deep convection, large-scale GWs arising from jet stream sources, and strong MWs in the MLT arising from strong surface flow over a small island. DEEPWAVE yielded a number of surprises, among

  6. System-level view of geospace dynamics: Challenges for high-latitude ground-based observations

    Science.gov (United States)

    Donovan, E.

    2014-12-01

    Increasingly, research programs including GEM, CEDAR, GEMSIS, GO Canada, and others are focusing on how geospace works as a system. Coupling sits at the heart of system level dynamics. In all cases, coupling is accomplished via fundamental processes such as reconnection and plasma waves, and can be between regions, energy ranges, species, scales, and energy reservoirs. Three views of geospace are required to attack system level questions. First, we must observe the fundamental processes that accomplish the coupling. This "observatory view" requires in situ measurements by satellite-borne instruments or remote sensing from powerful well-instrumented ground-based observatories organized around, for example, Incoherent Scatter Radars. Second, we need to see how this coupling is controlled and what it accomplishes. This demands quantitative observations of the system elements that are being coupled. This "multi-scale view" is accomplished by networks of ground-based instruments, and by global imaging from space. Third, if we take geospace as a whole, the system is too complicated, so at the top level we need time series of simple quantities such as indices that capture important aspects of the system level dynamics. This requires a "key parameter view" that is typically provided through indices such as AE and DsT. With the launch of MMS, and ongoing missions such as THEMIS, Cluster, Swarm, RBSP, and ePOP, we are entering a-once-in-a-lifetime epoch with a remarkable fleet of satellites probing processes at key regions throughout geospace, so the observatory view is secure. With a few exceptions, our key parameter view provides what we need. The multi-scale view, however, is compromised by space/time scales that are important but under-sampled, combined extent of coverage and resolution that falls short of what we need, and inadequate conjugate observations. In this talk, I present an overview of what we need for taking system level research to its next level, and how

  7. Physics-based features for identifying contextual factors affecting landmine detection with ground-penetrating radar

    Science.gov (United States)

    Ratto, Christopher R.; Morton, Kenneth D., Jr.; Collins, Leslie M.; Torrione, Peter A.

    2011-06-01

    It has been established throughout the ground-penetrating radar (GPR) literature that environmental factors can severely impact the performance of GPR sensors in landmine detection applications. Over the years, electromagnetic inversion techniques have been proposed for determining these factors with the goal of mitigating performance losses. However, these techniques are often computationally expensive and require models and responses from canonical targets, and therefore may not be appropriate for real-time route-clearance applications. An alternative technique for mitigating performance changes due to environmental factors is context-dependent classification, in which decision rules are adjusted based on contextual shifts identified from the GPR data. However, analysis of the performance of context-dependent learning has been limited to qualitative comparisons of contextually-similar GPR signatures and quantitative improvement to the ROC curve, while the actual information extracted regarding soils has not been investigated thoroughly. In this work, physics-based features of GPR data used in previous context-dependent approaches were extracted from simulated GPR data generated through Finite-Difference Time-Domain (FDTD) modeling. Statistical techniques where then used to predict several potential contextual factors, including soil dielectric constant, surface roughness, amount of subsurface clutter, and the existence of subsurface layering, based on the features. Results suggest that physics-based features of the GPR background may contain informatin regarding physical properties of the environment, and contextdependent classification based on these features can exploit information regarding these potentially-important environmental factors.

  8. Changes of IL-8 and IL-8 mRNA after blast-fragment combined injury in dogs

    Institute of Scientific and Technical Information of China (English)

    YAN Jia-chuan; YANG Zhi-huan; DONG Hong; FENG Gong; LI Xiao-yan; YIN You-guo

    2001-01-01

    To explore the characteristics and the mechanism of the blast-fragment combined injury.Methods: After the dogs were inflicted with high-velocity fragment injury on their left hindlimbs after blast injury,the IL-8 in the plasma and lung tissue supernatants were assayed with ELISA, and the expression of IL-8 mRNA in lung tissue was detected with in situ hybridization. Results: The levels of IL-8 in plasma and lung tissues were increased after blast, high velocity fragment and blast-fragment combined injuries respectively. IL-8 mRNA were upregulated after injuries. Conclusion: IL-8 may play a role in the occurrence and development of lung injury.Detecting the plasma levels of IL-8 may be quite helpful to estimate the injury.

  9. Interplanetary Charged Dust Magnetic Clouds Striking the Magnetosphere: Coordinated Space-based and Ground-based Observations

    Science.gov (United States)

    Russell, C. T.; Chi, Peter; Lai, Hairong

    In general, asteroids, meteoroids and dust do not interact with the plasma structures in the solar system, but after a collision between fast moving bodies the debris cloud contains nanoscale dust particles that are charged and behave like heavy ions. Dusty magnetic clouds are then accelerated to the solar wind speed. While they pose no threat to spacecraft because of the particle size, the coherency imposed by the magnetization of the cloud allows the cloud to interact with the Earth’s magnetosphere as well as the plasma in the immediate vicinity of the cloud. We call these clouds Interplanetary Field Enhancements (IFEs). These IFEs are a unique class of interplanetary field structures that feature cusp-shaped increases and decreases in the interplanetary magnetic field and a thin current sheet. The occurrence of IFEs is attributed to the interaction between the solar wind and dust particles produced in inter-bolide collisions. Previous spacecraft observations have confirmed that IFEs move with the solar wind. When IFEs strike the magnetosphere, they may distort the magnetosphere in several possible ways, such as producing a small indentation, a large scale compression, or a glancing blow. In any event if the IFE is slowed by the magnetosphere, the compression of the Earth’s field should be seen in the ground-based magnetic records that are continuously recorded. Thus it is important to understand the magnetospheric response to IFE arrival. In this study, we investigate the IFE structure observed by spacecraft upstream of the magnetosphere and the induced magnetic field perturbations observed by networks of ground magnetometers, including the THEMIS, CARISMA, McMAC arrays in North America and the IMAGE array in Europe. We find that, in a well-observed IFE event on December 24, 2006, all ground magnetometer stations observed an impulse at approximately 1217 UT when the IFE was expected to arrive at the Earth’s magnetopause. These ground stations spread across

  10. Advances in ground vehicle-based LADAR for standoff detection of road-side hazards

    Science.gov (United States)

    Hollinger, Jim; Vessey, Alyssa; Close, Ryan; Middleton, Seth; Williams, Kathryn; Rupp, Ronald; Nguyen, Son

    2016-05-01

    Commercial sensor technology has the potential to bring cost-effective sensors to a number of U.S. Army applications. By using sensors built for a widespread of commercial application, such as the automotive market, the Army can decrease costs of future systems while increasing overall capabilities. Additional sensors operating in alternate and orthogonal modalities can also be leveraged to gain a broader spectrum measurement of the environment. Leveraging multiple phenomenologies can reduce false alarms and make detection algorithms more robust to varied concealment materials. In this paper, this approach is applied to the detection of roadside hazards partially concealed by light-to-medium vegetation. This paper will present advances in detection algorithms using a ground vehicle-based commercial LADAR system. The benefits of augmenting a LADAR with millimeter-wave automotive radar and results from relevant data sets are also discussed.

  11. Ground-Based Sub-Millimagnitude CCD Photometry of Bright Stars using Snapshot Observations

    CERN Document Server

    Mann, Andrew W; Aldering, Greg

    2011-01-01

    We demonstrate ground-based sub-millimagnitude (10^7 electrons) to be acquired in a single integration; (iii) pointing the telescope so that all stellar images fall on the same detector pixels; and (iv) using a region of the CCD detector that is free of non-linear or aberrant pixels. We describe semi-automated observations with the Supernova Integrated Field Spectrograph (SNIFS) on the University of Hawaii 2.2m telescope on Mauna Kea, with which we achieved photometric precision as good as 5.2x10^-4 (0.56 mmag) with a 5 minute cadence over a two hour interval. In one experiment, we monitored 8 stars, each separated by several degrees, and achieved sub-mmag precision with a cadence (per star) of ~17 min. Our snapshot technique is suitable for automated searches for planetary transits among multiple, bright-stars.

  12. Global impacts of a Foreshock Bubble: Magnetosheath, magnetopause and ground-based observations

    CERN Document Server

    Archer, Martin; Eastwood, Jonathan; Schwartz, Steven; Horbury, Timothy

    2014-01-01

    Using multipoint observations we show, for the first time, that Foreshock Bubbles (FBs) have a global impact on Earth's magnetosphere. We show that an FB, a transient kinetic phenomenon due to the interaction of backstreaming suprathermal ions with a discontinuity, modifies the total pressure upstream of the bow shock showing a decrease within the FB's core and sheath regions. Magnetosheath plasma is accelerated towards the the intersection of the FB's current sheet with the bow shock resulting in fast, sunward, flows as well as outward motion of the magnetopause. Ground-based magnetometers also show signatures of this magnetopause motion simultaneously across at least 7 hours of magnetic local time, corresponding to a distance of 21.5 RE transverse to the Sun-Earth line along the magnetopause. These observed global impacts of the FB are in agreement with previous simulations and in stark contrast to the known localised, smaller scale effects of Hot Flow Anomalies (HFAs).

  13. Chlorine oxide in the stratospheric ozone layer Ground-based detection and measurement

    Science.gov (United States)

    Parrish, A.; De Zafra, R. L.; Solomon, P. M.; Barrett, J. W.; Carlson, E. R.

    1981-01-01

    Stratospheric chlorine oxide, a significant intermediate product in the catalytic destruction of ozone by atomic chlorine, has been detected and measured by a ground-based 204 GHz, millimeter-wave receiver. Data taken at latitude 42 deg N on 17 days between January 10 and February 18, 1980 yield an average chlorine oxide column density of approximately 1.05 x 10 to the 14th/sq cm or approximately 2/3 that of the average of eight in situ balloon flight measurements (excluding the anomalously high data of July 14, 1977) made over the past four years at 32 deg N. Less chlorine oxide below 35 km and a larger vertical gradient than predicted by theoretical models of the stratospheric ozone layer are found.

  14. Optical turbulence forecast: toward a new era of ground-based astronomy

    CERN Document Server

    Masciadri, E

    2009-01-01

    The simulation of the optical turbulence (OT) for astronomical applications obtained with non-hydrostatic atmospherical models at meso-scale presents, with respect to measurements, some advantages. The future of the ground-based astronomy relies upon the potentialities and feasibility of the ELTs. Our ability in knowing, controlling and 'managing' the effects of the turbulence on such a new generation telescopes and facilities are determinant to assure their competitiveness with respect to the space astronomy. In the past several studies have been carried out proving the feasibility of the simulation of realistic Cn2 profiles above astronomical sites. The European Community (FP6 Program) decided recently to fund a Project aiming, from one side, to prove the feasibility of the OT forecasts and the ability of meso-scale models in discriminating astronomical sites from optical turbulence point of view and, from the other side, to boost the development of this discipline at the borderline between the astrophysics...

  15. Quantitative analysis results of CE-1 X-ray fluorescence spectrometer ground base experiment

    Institute of Scientific and Technical Information of China (English)

    CUI Xing-Zhu; GAO Min; YANG Jia-Wei; WANG Huan-Yu; ZHANG Cheng-Mo; CHEN Yong; ZHANG Jia-Yu; PENG Wen-Xi; CAO Xue-Lei; LIANG Xiao-Hua; WANG Jin-Zhou

    2008-01-01

    As the nearest celestial body to the earth, the moon has become a hot spot again in astronomy field recently. The element analysis is a much important subject in many lunar projects. Remote X-ray spectrometry plays an important role in the geochemical exploration of the solar bodies. Because of th equasi-vacuum atmosphere on the moon, which has no absorption of X-ray, the X-ray fluorescence analysis is an effective way to determine the elemental abundance of lunar surface. The CE-1 X-ray fluorescence spectrometer (CE-1/XFS) aims to map the major elemental compositions on the lunar surface. This paper describes a method for quantitative analysis of elemental compositions. A series of ground base experiments are done to examine the capability of XFS. The obtained results, which show a reasonable agreement with the certified values at a 30% uncertainty level for major elements, are presented.

  16. A 14-day ground-based hypokinesia study in nonhuman primates: A compilation of results

    Science.gov (United States)

    Kazarian, L.; Cann, C. E.; Parfitt, M.; Simmons, D.; Morey-Holton, E.

    1981-01-01

    A 14 day ground based hypokinesia study with rhesus monkeys was conducted to determine if a spaceflight of similar duration might affect bone remodeling and calcium homeostatis. The monkeys were placed in total body casts and sacrificed either immediately upon decasting or 14 days after decasting. Changes in vertebral strength were noted and further deterioration of bone strength continued during the recovery phase. Resorption in the vertebrae increased dramatically while formation decreased. Cortical bone formation was impaired in the long bones. The immobilized animals showed a progressive decrease in total serum calcium which rebounded upon remobilization. Most mandibular parameters remained unchanged during casting except for retardation of osteon birth or maturation rate and density distribution of matrix and mineral moieties.

  17. Ground-based Gamma-Ray Observations of Pulsars and their Nebulae: Towards a New Order

    CERN Document Server

    De Jager, O C

    2005-01-01

    The excellent sensitivity and high resolution capability of wide FoV ground-based imaging atmospheric Cerenkov telescopes allow us for the first time to resolve the morphological structures of pulsar wind nebulae (PWN) which are older and more extended than the Crab Nebula. VHE gamma-ray observations of such extended nebulae (with field strengths below ~ 20 micro Gauss) probe the electron component corresponding to the unseen extreme ultraviolet (EUV) synchrotron component, which measures electron injection from earlier evolutionary epochs. VHE observations of PWN therefore introduce a new window on PWN research. This review paper also identifies conditions for maximal VHE visbility of PWN. Regarding pulsar pulsed emission, it is becoming clear that the threshold energies of current telescopes are not sufficient to probe the pulsed gamma-ray component from canonical pulsars. Theoretical estimates of pulsed gamma-ray emission from millisecond pulsars seem to converge and it becomes clear that such detections w...

  18. Ground target detection based on discrete cosine transform and Rényi entropy for imaging ladar

    Science.gov (United States)

    Xu, Yuannan; Chen, Weili; Li, Junwei; Dong, Yanbing

    2016-01-01

    The discrete cosine transform (DCT) due to its excellent properties that the images can be represented in spatial/spatial-frequency domains, has been applied in sequence data analysis and image fusion. For intensity and range images of ladar, through the DCT using one dimension window, the statistical property of Rényi entropy for images is studied. We also analyzed the change of Rényi entropy's statistical property in the ladar intensity and range images when the man-made objects appear. From this foundation, a novel method for generating saliency map based on DCT and Rényi entropy is proposed. After that, ground target detection is completed when the saliency map is segmented using a simple and convenient threshold method. For the ladar intensity and range images, experimental results show the proposed method can effectively detect the military vehicles from complex earth background with low false alarm.

  19. On the Interpretation of Gravity Wave Measurements by Ground-Based Lidars

    Directory of Open Access Journals (Sweden)

    Andreas Dörnbrack

    2017-03-01

    Full Text Available This paper asks the simple question: How can we interpret vertical time series of middle atmosphere gravity wave measurements by ground-based temperature lidars? Linear wave theory is used to show that the association of identified phase lines with quasi-monochromatic waves should be considered with great care. The ambient mean wind has a substantial effect on the inclination of the detected phase lines. The lack of knowledge about the wind might lead to a misinterpretation of the vertical propagation direction of the observed gravity waves. In particular, numerical simulations of three archetypal atmospheric mountain wave regimes show a sensitivity of virtual lidar observations on the position relative to the mountain and on the scale of the mountain.

  20. Concurrent aerial and ground-based optical turbulence measurements along a long elevated path

    Science.gov (United States)

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

    1999-08-01

    We report concurrent ground-based scintillator/airborne constant-current anemometer (CCA) measurements made along a 51.4 km-long slant path between Salinas and North Oscura peaks, NM. Simultaneous path-averaged refractive index structure parameter (Cn2) measurements from the CCA and the scintillometer show good agreement, with deviations apparently due to localized effects of underlying topography and metrology. Statistics from both data sets are presented in the form of histograms and cumulative distribution functions. CCA Cn2 point measurements are compared to underlying surface topography. We discuss possible effects of instruments anomalies, analysis methods, and atmospheric velocity fluctuation levels. We present conclusions and made recommendations for future similar experimental efforts.

  1. Space situational awareness satellites and ground based radiation counting and imaging detector technology

    Energy Technology Data Exchange (ETDEWEB)

    Jansen, Frank, E-mail: frank.jansen@dlr.de [DLR Institute of Space Systems, Robert-Hooke-Str. 7, 28359 Bremen (Germany); Behrens, Joerg [DLR Institute of Space Systems, Robert-Hooke-Str. 7, 28359 Bremen (Germany); Pospisil, Stanislav [Czech Technical University, IEAP, 12800 Prague 2, Horska 3a/22 (Czech Republic); Kudela, Karel [Slovak Academy of Sciences, IEP, 04001 Kosice, Watsonova 47 (Slovakia)

    2011-05-15

    We review the current status from the scientific and technological point of view of solar energetic particles, solar and galactic cosmic ray measurements as well as high energy UV-, X- and gamma-ray imaging of the Sun. These particles and electromagnetic data are an important tool for space situational awareness (SSA) aspects like space weather storm predictions to avoid failures in space, air and ground based technological systems. Real time data acquisition, position and energy sensitive imaging are demanded by the international space weather forecast services. We present how newly developed, highly miniaturized radiation detectors can find application in space in view of future SSA related satellites as a novel space application due to their counting and imaging capabilities.

  2. Impact of particles on the Planck HFI detectors: Ground-based measurements and physical interpretation

    CERN Document Server

    Catalano, A; Atik, Y; Benoit, A; Bréele, E; Bock, J J; Camus, P; Chabot, M; Charra, M; Crill, B P; Coron, N; Coulais, A; Désert, F -X; Fauvet, L; Giraud-Héraud, Y; Guillaudin, O; Holmes, W; Jones, W C; Lamarre, J -M; Macías-Pérez, J; Martinez, M; Miniussi, A; Monfardini, A; Pajot, F; Patanchon, G; Pelissier, A; Piat, M; Puget, J -L; Renault, C; Rosset, C; Santos, D; Sauvé, A; Spencer, L D; Sudiwala, R

    2014-01-01

    The Planck High Frequency Instrument (HFI) surveyed the sky continuously from August 2009 to January 2012. Its noise and sensitivity performance were excellent, but the rate of cosmic ray impacts on the HFI detectors was unexpectedly high. Furthermore, collisions of cosmic rays with the focal plane produced transient signals in the data (glitches) with a wide range of characteristics. A study of cosmic ray impacts on the HFI detector modules has been undertaken to categorize and characterize the glitches, to correct the HFI time-ordered data, and understand the residual effects on Planck maps and data products. This paper presents an evaluation of the physical origins of glitches observed by the HFI detectors. In order to better understand the glitches observed by HFI in flight, several ground-based experiments were conducted with flight-spare HFI bolometer modules. The experiments were conducted between 2010 and 2013 with HFI test bolometers in different configurations using varying particles and impact ener...

  3. Ground-based activities in preparation of SELENE ISS experiment on self-rewetting fluids

    Science.gov (United States)

    Savino, R.; Abe, Y.; Castagnolo, D.; Celata, G. P.; Kabov, O.; Kawaji, M.; Sato, M.; Tanaka, K.; Thome, J. R.; Van Vaerenbergh, S.

    2011-12-01

    SELENE (SELf rewetting fluids for thermal ENErgy management) is a microgravity experiment proposed to the European Space Agency (ESA) in response to the Announcement of Opportunities for Physical Sciences. Main objectives of the microgravity research onboard ISS include the quantitative investigation of heat transfer performances of "self-rewetting fluids" and "nano self-rewetting fluids" in model heat pipes and validation of adequate theoretical and numerical modelling able to predict their behaviour in microgravity conditions. This article summarizes the results of ground-based research activities in preparation of the microgravity experiments. They include: 1) thermophysical properties measurements; 2) study of thermo-soluto-capillary effects in micro-channels; 3) numerical modelling; 4) thermal and concentration distribution measurements with optical (e.g. interferometric) and intrusive techniques; 5) surface tension-driven effects and thermal performances test on different capillary structures and heat pipes; 6) breadboards development and support to definition of scientific requirements.

  4. Future Ground-Based Solar System Research: a Prospective Workshop Summary

    Science.gov (United States)

    Boehnhardt, H.; Käufl, H. U.

    2009-09-01

    The article tries to provide a perspective summary of the planetary science to be performed with future extremely large telescopes (ELTs) as an outcome of the workshop on ‘Future Ground-based Solar System Research: Synergies between Space Probes and Space Telescopes’ held on 8-12 September 2008 in Portoferraio on Isola d’ Elba, Italy. It addresses science cases on solar system objects that might challenge the capabilities of ELTs and that provide a major step forward in the knowledge and understanding of planetary system objects per se and all populations. We also compile high-level requirements for such telescopes and their instrumentation that should enable successful ELT usage for research on objects in the Solar System, the ‘disturbing foreground to real astronomy’.

  5. Finding extraterrestrial life using ground-based high-resolution spectroscopy

    CERN Document Server

    Snellen, Ignas; Poole, Rudolf Le; Brogi, Matteo; Birkby, Jayne

    2013-01-01

    Exoplanet observations promise one day to unveil the presence of extraterrestrial life. Atmospheric compounds in strong chemical disequilibrium would point to large-scale biological activity just as oxygen and methane do in the Earth's atmosphere. The cancellation of both the Terrestrial Planet Finder and Darwin missions means that it is unlikely that a dedicated space telescope to search for biomarker gases in exoplanet atmospheres will be launched within the next 25 years. Here we show that ground-based telescopes provide a strong alternative for finding biomarkers in exoplanet atmospheres through transit observations. Recent results on hot Jupiters show the enormous potential of high-dispersion spectroscopy to separate the extraterrestrial and telluric signals making use of the Doppler shift of the planet. The transmission signal of oxygen from an Earth-twin orbiting a small red dwarf star is only a factor 3 smaller than that of carbon monoxide recently detected in the hot Jupiter tau Bootis b, albeit such...

  6. AOLI: Near-diffraction limited imaging in the visible on large ground-based telescopes

    CERN Document Server

    Mackay, Craig; King, David; Labadie, Lucas; Antolin, Marta Puga; Garrido, Antonio; Colodro-Conde, Carlos; Lopez, Roberto; Muthusubramanian, Balaji; Oscoz, Alejandro; Rodriguez-Ramos, Jose; Rodriquez-Ramos, Luis; Fernandez-Valdivia, Jose; Velasco, Sergio

    2016-01-01

    The combination of Lucky Imaging with a low order adaptive optics system was demonstrated very successfully on the Palomar 5m telescope nearly 10 years ago. It is still the only system to give such high-resolution images in the visible or near infrared on ground-based telescope of faint astronomical targets. The development of AOLI for deployment initially on the WHT 4.2 m telescope in La Palma, Canary Islands, will be described in this paper. In particular, we will look at the design and status of our low order curvature wavefront sensor which has been somewhat simplified to make it more efficient, ensuring coverage over much of the sky with natural guide stars as reference object. AOLI uses optically butted electron multiplying CCDs to give an imaging array of 2000 x 2000 pixels.

  7. Bubble motion in a rotating liquid body. [ground based tests for space shuttle experiments

    Science.gov (United States)

    Annamalai, P.; Subramanian, R. S.; Cole, R.

    1982-01-01

    The behavior of a single gas bubble inside a rotating liquid-filled sphere has been investigated analytically and experimentally as part of ground-based investigations aimed at aiding in the design and interpretation of Shuttle experiments. In the analysis, a quasi-static description of the motion of a bubble was developed in the limit of small values of the Taylor number. A series of rotation experiments using air bubbles and silicone oils were designed to match the conditions specified in the analysis, i.e., the bubble size, sphere rotation rate, and liquid kinematic viscosity were chosen such that the Taylor number was much less than unity. The analytical description predicts the bubble velocity and its asymptotic location. It is shown that the asymptotic position is removed from the axis of rotation.

  8. A review of turbulence measurements using ground-based wind lidars

    DEFF Research Database (Denmark)

    Sathe, Ameya; Mann, Jakob

    2013-01-01

    pioneered in the first 15 yr, i.e., from 1972–1997, when standard techniques could not be used to measure turbulence. Obtaining unfiltered turbulence statistics from the large probe volume of the lidars has been and still remains the most challenging aspect. Until now, most of the processing algorithms......A review of turbulence measurements using ground-based wind lidars is carried out. Works performed in the last 30 yr, i.e., from 1972–2012 are analyzed. More than 80% of the work has been carried out in the last 15 yr, i.e., from 1997–2012. New algorithms to process the raw lidar data were...... that have been developed have shown that by combining an isotropic turbulence model with raw lidar measurements, we can obtain unfiltered statistics.We believe that an anisotropic turbulence model will provide a more realistic measure of turbulence statistics. Future development in algorithms will depend...

  9. Flight validation of ground-based assessment for control power requirements at high angles of attack

    Science.gov (United States)

    Ogburn, Marilyn E.; Ross, Holly M.; Foster, John V.; Pahle, Joseph W.; Sternberg, Charles A.; Traven, Ricardo; Lackey, James B.; Abbott, Troy D.

    1994-01-01

    A review is presented in viewgraph format of an ongoing NASA/U.S. Navy study to determine control power requirements at high angles of attack for the next generation high-performance aircraft. This paper focuses on recent flight test activities using the NASA High Alpha Research Vehicle (HARV), which are intended to validate results of previous ground-based simulation studies. The purpose of this study is discussed, and the overall program structure, approach, and objectives are described. Results from two areas of investigation are presented: (1) nose-down control power requirements and (2) lateral-directional control power requirements. Selected results which illustrate issues and challenges that are being addressed in the study are discussed including test methodology, comparisons between simulation and flight, and general lessons learned.

  10. Precision in ground based solar polarimetry: Simulating the role of adaptive optics

    CERN Document Server

    Nagaraju, K

    2012-01-01

    Accurate measurement of polarization in spectral lines is important for the reliable inference of magnetic fields on the Sun. For ground based observations, polarimetric precision is severely limited by the presence of Earth's atmosphere. Atmospheric turbulence (seeing) produces signal fluctuations which combined with the non-simultaneous nature of the measurement process cause intermixing of the Stokes parameters known as seeing induced polarization cross-talk. Previous analysis of this effect (Judge et al., 2004) suggests that cross-talk is reduced not only with increase in modulation frequency but also by compensating the seeing induced image aberrations by an Adaptive Optics (AO) system. However, in those studies the effect of higher order image aberrations than those corrected by the AO system was not taken into account. We present in this paper an analysis of seeing induced cross-talk in the presence of higher order image aberrations through numerical simulation. In this analysis we find that the amount...

  11. Intermittency of the turbulent processes in the Earth's magnetosphere detected from the ground-based measurements

    Science.gov (United States)

    Stepanova, Marina; Foppiano, Alberto; Ovalle, Elias; Antonova, Elizavieta; Troshichev, Oleg

    2008-11-01

    Turbulent processes in the Earth's magnetosphere are reflected in the dynamical behavior of the geomagnetic indices and other parameters determined from ground based observations. Intermittent properties of one minute Polar Cap (PC) index and auroral radio wave absorption are studied using 1995-2000 data sets. It was found that the probability distribution functions (PDFs) of both PC-index and absorption fluctuations display a strong non-Gaussian shape. This indicates that they are not characterized by a global time self-similarity but rather exhibit intermittency, as previously reported for solar wind velocity and auroral electrojet index values. In the case of the auroral absorption it was also found that intermittency strongly depends on the magnetic local time, being largest in the nighttime sector. This shows that the acceleration of precipitating particles is intermittent, especially near the substorm eye, where the level of turbulence increases. Application of the Local Intermittency Measure (LIM) technique confirms the aforementioned results to a better precision.

  12. Integrated ground-based and remotely sensed data to support global studies of environmental change

    Energy Technology Data Exchange (ETDEWEB)

    Olson, R.J.; Turner, R.S.; Garten, C.T.

    1994-09-15

    Data centers routinely archive and distribute large databases of high quality and with rigorous documentation but, to meet the needs of global studies effectively and efficiently, data centers must go beyond these traditional roles. Global studies of environmental change require integrated databases of multiple data types that are accurately coordinated in terms of spatial, temporal and thematic properties. Such datasets must be designed and developed jointly by scientific researchers, computer specialists, and policy analysts. The presentation focuses on our approach for organizing data from ground-based research programs so that the data can be linked with remotely sensed data and other map data into integrated databases with spatial, temporal, and thematic characteristics relevant to global studies. The development of an integrated database for Net Primary Productivity is described to illustrate the process.

  13. Dynamical study of low Earth orbit debris collision avoidance using ground based laser

    Directory of Open Access Journals (Sweden)

    N.S. Khalifa

    2015-06-01

    Full Text Available The objective of this paper was to investigate the orbital velocity changes due to the effect of ground based laser force. The resulting perturbations of semi-major axis, miss distance and collision probability of two approaching objects are studied. The analytical model is applied for low Earth orbit debris of different eccentricities and area to mass ratio and the numerical test shows that laser of medium power ∼5 kW can perform a small change ΔV‾ of an average magnitude of 0.2 cm/s which can be accumulated over time to be about 3 cm/day. Moreover, it is confirmed that applying laser ΔV‾ results in decreasing collision probability and increasing miss distance in order to avoid collision.

  14. Ground characterization and roof mapping:Online sensor signal-based change detection

    Institute of Scientific and Technical Information of China (English)

    Bahrampour Soheil; Rostami Jamal; Ray Asok; Naeimipour Ali; Collins Craig

    2015-01-01

    Measurement while drilling systems are becoming an important part of excavation operations for rock characterization and ground support design that require reliable information on rock strength and loca-tion&frequency of joints or voids. This paper focuses on improving rock characterization algorithms for instrumented roof-bolter systems. For this purpose, an improved void detection algorithm is proposed, where the underlying theory is built upon the concept of mean change detection based on the feed pressure signals. In addition, the application of acoustic sensing for void detection is examined and it is shown that the variance of the filtered acoustic signal is correlated to the strength of the material being drilled. The proposed algorithm has been validated on the data collected from full-scale drilling tests in various concrete and rock samples at the J. H. Fletcher facility.

  15. Sfm_georef: Automating image measurement of ground control points for SfM-based projects

    Science.gov (United States)

    James, Mike R.

    2016-04-01

    Deriving accurate DEM and orthomosaic image products from UAV surveys generally involves the use of multiple ground control points (GCPs). Here, we demonstrate the automated collection of GCP image measurements for SfM-MVS processed projects, using sfm_georef software (James & Robson, 2012; http://www.lancaster.ac.uk/staff/jamesm/software/sfm_georef.htm). Sfm_georef was originally written to provide geo-referencing procedures for SfM-MVS projects. It has now been upgraded with a 3-D patch-based matching routine suitable for automating GCP image measurement in both aerial and ground-based (oblique) projects, with the aim of reducing the time required for accurate geo-referencing. Sfm_georef is compatible with a range of SfM-MVS software and imports the relevant files that describe the image network, including camera models and tie points. 3-D survey measurements of ground control are then provided, either for natural features or artificial targets distributed over the project area. Automated GCP image measurement is manually initiated through identifying a GCP position in an image by mouse click; the GCP is then represented by a square planar patch in 3-D, textured from the image and oriented parallel to the local topographic surface (as defined by the 3-D positions of nearby tie points). Other images are then automatically examined by projecting the patch into the images (to account for differences in viewing geometry) and carrying out a sub-pixel normalised cross-correlation search in the local area. With two or more observations of a GCP, its 3-D co-ordinates are then derived by ray intersection. With the 3-D positions of three or more GCPs identified, an initial geo-referencing transform can be derived to relate the SfM-MVS co-ordinate system to that of the GCPs. Then, if GCPs are symmetric and identical, image texture from one representative GCP can be used to search automatically for all others throughout the image set. Finally, the GCP observations can be

  16. TESTING GROUND BASED GEOPHYSICAL TECHNIQUES TO REFINE ELECTROMAGNETIC SURVEYS NORTH OF THE 300 AREA HANFORD WASHINGTON

    Energy Technology Data Exchange (ETDEWEB)

    PETERSEN SW

    2010-12-02

    Airborne electromagnetic (AEM) surveys were flown during fiscal year (FY) 2008 within the 600 Area in an attempt to characterize the underlying subsurface and to aid in the closure and remediation design study goals for the 200-PO-1 Groundwater Operable Unit (OU). The rationale for using the AEM surveys was that airborne surveys can cover large areas rapidly at relatively low costs with minimal cultural impact, and observed geo-electrical anomalies could be correlated with important subsurface geologic and hydrogeologic features. Initial interpretation of the AEM surveys indicated a tenuous correlation with the underlying geology, from which several anomalous zones likely associated with channels/erosional features incised into the Ringold units were identified near the River Corridor. Preliminary modeling resulted in a slightly improved correlation but revealed that more information was required to constrain the modeling (SGW-39674, Airborne Electromagnetic Survey Report, 200-PO-1 Groundwater Operable Unit, 600 Area, Hanford Site). Both time-and frequency domain AEM surveys were collected with the densest coverage occurring adjacent to the Columbia River Corridor. Time domain surveys targeted deeper subsurface features (e.g., top-of-basalt) and were acquired using the HeliGEOTEM{reg_sign} system along north-south flight lines with a nominal 400 m (1,312 ft) spacing. The frequency domain RESOLVE system acquired electromagnetic (EM) data along tighter spaced (100 m [328 ft] and 200 m [656 ft]) north-south profiles in the eastern fifth of the 200-PO-1 Groundwater OU (immediately adjacent to the River Corridor). The overall goal of this study is to provide further quantification of the AEM survey results, using ground based geophysical methods, and to link results to the underlying geology and/or hydrogeology. Specific goals of this project are as follows: (1) Test ground based geophysical techniques for the efficacy in delineating underlying geology; (2) Use ground

  17. Polarimetric mountain based radio-occultation for rain detection: The ROHP-PAZ ground campaign

    Science.gov (United States)

    Padulles, Ramon; Cardellach, Estel; Tomas, Sergio; de la Torre, Manuel; Turk, Joe

    2014-05-01

    The Radio Occultation and Heavy Precipitation experiment aboard the PAZ Low Earth Orbiter (ROHP-PAZ) is a mission of opportunity: The Spanish Ministry of Science and Innovation (MICINN) approved in 2009 a proposal to include a polarimetric Global Navigation Satellite System (GNSS) Radio-Occultation (RO) payload on board of the Spanish Earth Observation satellite PAZ. This will be a new technique that has never been tested before, that aims to improve the knowledge of precipitation through simultaneous thermodynamic and vertical rain profiles. Prior to the launch of the satellite, expected for 2014, a ground experimental campaign is being conducted with the goal of starting the process of identifying and understanding all the factors that might affect the polarimetric RO observables. The campaign is being carried out at the top of Puig Sesolles, a 1667m peak in the Natural Park of Montseny (41º46'24 N, 2º26'17 E), 50 km N-NE from Barcelona, with clear views over the horizon to the South (East to West) direction, an area in which intense precipitation events tend to occur a few times per year. The campaign uses a ICE-CSIC/IEEC's GOLD-RTR open-loop receiver initially designed for collecting GNSS signals reflected off the sea surface. The receiver has been adjusted to track occulting GNSS radio-links. A double polarization (H and V) GNSS antenna has been designed and manufactured by the Polytechnic University of Barcelona (UPC) team for this particular ground-based experiment. The antenna is a phase-array made of 7 elements, each of them being a square patch built using a Rogers 4003 substrate, and symmetrically fed by four probes. It provides a pattern of 12.9 dB peak gain, 45 degrees half-power beam-width, and <-35 dB cross-polar isolation at the peak (better than -30 dB in the main lobe). The preliminary results show that not only precipitation, but also other factors are affecting the GNSS signal, wich means that the polarimetric signal is richer than expected

  18. An assessment of the performance of global rainfall estimates without ground-based observations

    Directory of Open Access Journals (Sweden)

    C. Massari

    2017-09-01

    Full Text Available Satellite-based rainfall estimates over land have great potential for a wide range of applications, but their validation is challenging due to the scarcity of ground-based observations of rainfall in many areas of the planet. Recent studies have suggested the use of triple collocation (TC to characterize uncertainties associated with rainfall estimates by using three collocated rainfall products. However, TC requires the simultaneous availability of three products with mutually uncorrelated errors, a requirement which is difficult to satisfy with current global precipitation data sets. In this study, a recently developed method for rainfall estimation from soil moisture observations, SM2RAIN, is demonstrated to facilitate the accurate application of TC within triplets containing two state-of-the-art satellite rainfall estimates and a reanalysis product. The validity of different TC assumptions are indirectly tested via a high-quality ground rainfall product over the contiguous United States (CONUS, showing that SM2RAIN can provide a truly independent source of rainfall accumulation information which uniquely satisfies the assumptions underlying TC. On this basis, TC is applied with SM2RAIN on a global scale in an optimal configuration to calculate, for the first time, reliable global correlations (vs. an unknown truth of the aforementioned products without using a ground benchmark data set. The analysis is carried out during the period 2007–2012 using daily rainfall accumulation products obtained at 1° × 1° spatial resolution. Results convey the relatively high performance of the satellite rainfall estimates in eastern North and South America, southern Africa, southern and eastern Asia, eastern Australia, and southern Europe, as well as complementary performances between the reanalysis product and SM2RAIN, with the first performing reasonably well in the Northern Hemisphere and the second providing very good performance in the Southern

  19. TEMIS UV product validation using NILU-UV ground-based measurements in Thessaloniki, Greece

    Science.gov (United States)

    Zempila, Melina-Maria; van Geffen, Jos H. G. M.; Taylor, Michael; Fountoulakis, Ilias; Koukouli, Maria-Elissavet; van Weele, Michiel; van der A, Ronald J.; Bais, Alkiviadis; Meleti, Charikleia; Balis, Dimitrios

    2017-06-01

    This study aims to cross-validate ground-based and satellite-based models of three photobiological UV effective dose products: the Commission Internationale de l'Éclairage (CIE) erythemal UV, the production of vitamin D in the skin, and DNA damage, using high-temporal-resolution surface-based measurements of solar UV spectral irradiances from a synergy of instruments and models. The satellite-based Tropospheric Emission Monitoring Internet Service (TEMIS; version 1.4) UV daily dose data products were evaluated over the period 2009 to 2014 with ground-based data from a Norsk Institutt for Luftforskning (NILU)-UV multifilter radiometer located at the northern midlatitude super-site of the Laboratory of Atmospheric Physics, Aristotle University of Thessaloniki (LAP/AUTh), in Greece. For the NILU-UV effective dose rates retrieval algorithm, a neural network (NN) was trained to learn the nonlinear functional relation between NILU-UV irradiances and collocated Brewer-based photobiological effective dose products. Then the algorithm was subjected to sensitivity analysis and validation. The correlation of the NN estimates with target outputs was high (r = 0. 988 to 0.990) and with a very low bias (0.000 to 0.011 in absolute units) proving the robustness of the NN algorithm. For further evaluation of the NILU NN-derived products, retrievals of the vitamin D and DNA-damage effective doses from a collocated Yankee Environmental Systems (YES) UVB-1 pyranometer were used. For cloud-free days, differences in the derived UV doses are better than 2 % for all UV dose products, revealing the reference quality of the ground-based UV doses at Thessaloniki from the NILU-UV NN retrievals. The TEMIS UV doses used in this study are derived from ozone measurements by the SCIAMACHY/Envisat and GOME2/MetOp-A satellite instruments, over the European domain in combination with SEVIRI/Meteosat-based diurnal cycle of the cloud cover fraction per 0. 5° × 0. 5° (lat × long) grid cells. TEMIS

  20. Observation of TGFs onboard "Vernov" satellite and TGEs in ground-based experiments

    Science.gov (United States)

    Bogomolov, Vitaly; Panasyuk, Mikhail; Svertilov, Sergey; Garipov, Gali; Iyudin, Anatoly; Klimov, Pavel; Morozenko, Violetta; Maximov, Ivan; Mishieva, Tatiana; Klimov, Stanislav; Pozanenko, Alexey; Rothkaehl, Hanna

    2016-04-01

    "Vernov" satellite with RELEC experiment on-board was launched on 2014 July, 8 into a polar solar-synchronous orbit. The payload includes DRGE gamma-ray spectrometer providing measurements in 10-3000 keV energy range with four detectors directed to atmosphere. Total area of DRGE detectors is ~500 cm2. The data were recorded both in monitoring and gamma by gamma modes with timing accuracy ~15 us. Several TGF candidates with 10-40 gammas in a burst with duration instruments on-board "Vernov" satellite shows the absence of significant electromagnetic pulses around correspondent time moments. Comparison with WWLLN lightning network data base also indicates that there were no thunderstorms connected with most of detected TGF candidates. Possible connection of these flashes with electron precipitations is discussed. Ground-based experiments, with similar gamma-spectrometers were conducted, to study the spectral, temporal and spatial characteristics of TGEs in 20-3000 keV energy range, as well, as to search the fast hard X-ray and gamma-ray flashes possibly appearing at the moment of lightning. The time of each gamma-quantum interaction was recorded with an ~15 us s accuracy together with detailed spectral data. Measurements were done on the ground at Moscow region, and at mountain altitude in Armenia at Aragatz station. During the time interval covering spring, summer and autumn of 2015 a number of TGEs were detected. Measured low-energy gamma-ray spectra usually contain a set of lines that can be interpreted as radiation of Rn-222 daughter isotopes. The increase of Rn-222 radiation was detected during rainfalls with thunderstorm, as well, as during rainy weather without thunderstorms. Variations of Rn-222 radiation dominate at low energies (measure low energy gamma-radiation from the electrons accelerated in thunderclouds. There were no significant flashes with duration of ~1ms detected in coincidence with a nearby lightnings.

  1. An evaluation of IASI-NH3 with ground-based Fourier transform infrared spectroscopy measurements

    Science.gov (United States)

    Dammers, Enrico; Palm, Mathias; Van Damme, Martin; Vigouroux, Corinne; Smale, Dan; Conway, Stephanie; Toon, Geoffrey C.; Jones, Nicholas; Nussbaumer, Eric; Warneke, Thorsten; Petri, Christof; Clarisse, Lieven; Clerbaux, Cathy; Hermans, Christian; Lutsch, Erik; Strong, Kim; Hannigan, James W.; Nakajima, Hideaki; Morino, Isamu; Herrera, Beatriz; Stremme, Wolfgang; Grutter, Michel; Schaap, Martijn; Wichink Kruit, Roy J.; Notholt, Justus; Coheur, Pierre-F.; Erisman, Jan Willem

    2016-08-01

    Global distributions of atmospheric ammonia (NH3) measured with satellite instruments such as the Infrared Atmospheric Sounding Interferometer (IASI) contain valuable information on NH3 concentrations and variability in regions not yet covered by ground-based instruments. Due to their large spatial coverage and (bi-)daily overpasses, the satellite observations have the potential to increase our knowledge of the distribution of NH3 emissions and associated seasonal cycles. However the observations remain poorly validated, with only a handful of available studies often using only surface measurements without any vertical information. In this study, we present the first validation of the IASI-NH3 product using ground-based Fourier transform infrared spectroscopy (FTIR) observations. Using a recently developed consistent retrieval strategy, NH3 concentration profiles have been retrieved using observations from nine Network for the Detection of Atmospheric Composition Change (NDACC) stations around the world between 2008 and 2015. We demonstrate the importance of strict spatio-temporal collocation criteria for the comparison. Large differences in the regression results are observed for changing intervals of spatial criteria, mostly due to terrain characteristics and the short lifetime of NH3 in the atmosphere. The seasonal variations of both datasets are consistent for most sites. Correlations are found to be high at sites in areas with considerable NH3 levels, whereas correlations are lower at sites with low atmospheric NH3 levels close to the detection limit of the IASI instrument. A combination of the observations from all sites (Nobs = 547) give a mean relative difference of -32.4 ± (56.3) %, a correlation r of 0.8 with a slope of 0.73. These results give an improved estimate of the IASI-NH3 product performance compared to the previous upper-bound estimates (-50 to +100 %).

  2. Mountain wave PSC dynamics and microphysics from ground-based lidar measurements and meteorological modeling

    Directory of Open Access Journals (Sweden)

    J. Reichardt

    2004-01-01

    Full Text Available The day-long observation of a polar stratospheric cloud (PSC by two co-located ground-based lidars at the Swedish research facility Esrange (67.9° N, 21.1° E on 16 January 1997 is analyzed in terms of PSC dynamics and microphysics. Mesoscale modeling is utilized to simulate the meteorological setting of the lidar measurements. Microphysical properties of the PSC particles are retrieved by comparing the measured particle depolarization ratio and the PSC-averaged lidar ratio with theoretical optical data derived for different particle shapes. In the morning, nitric acid trihydrate (NAT particles and then increasingly coexisting liquid ternary aerosol (LTA were detected as outflow from a mountain wave-induced ice PSC upwind Esrange. The NAT PSC is in good agreement with simulations for irregular-shaped particles with length-to-diameter ratios between 0.75 and 1.25, maximum dimensions from 0.7 to 0.9 µm, and a number density from 8 to 12 cm-3 and the coexisting LTA droplets had diameters from 0.7 to 0.9 µm, a refractive index of 1.39 and a number density from 7 to 11 cm-3. The total amount of condensed HNO3 was in the range of 8–12 ppbv. The data provide further observational evidence that NAT forms via deposition nucleation on ice particles as a number of recently published papers suggest. By early afternoon the mountain-wave ice PSC expanded above the lidar site. Its optical data indicate a decrease in minimum particle size from 3 to 1.9 µm with time. Later on, following the weakening of the mountain wave, wave-induced LTA was observed only. Our study demonstrates that ground-based lidar measurements of PSCs can be comprehensively interpreted if combined with mesoscale meteorological data.

  3. Critical Evaluation of the ISCCP Simulator Using Ground-Based Remote Sensing Data

    Energy Technology Data Exchange (ETDEWEB)

    Mace, G G; Houser, S; Benson, S; Klein, S A; Min, Q

    2009-11-02

    Given the known shortcomings in representing clouds in Global Climate Models (GCM) comparisons with observations are critical. The International Satellite Cloud Climatology Project (ISCCP) diagnostic products provide global descriptions of cloud top pressure and column optical depth that extends over multiple decades. The necessary limitations of the ISCCP retrieval algorithm require that before comparisons can be made between model output and ISCCP results the model output must be modified to simulate what ISCCP would diagnose under the simulated circumstances. We evaluate one component of the so-called ISCCP simulator in this study by comparing ISCCP and a similar algorithm with various long-term statistics derived from the Atmospheric Radiation Measurement (ARM) Southern Great Plains (SGP) Climate Research Facility ground-based remote sensors. We find that were a model to simulate the cloud radiative profile with the same accuracy as can be derived from the ARM data, then the likelihood of that occurrence being placed in the same cloud top pressure and optical depth bin as ISCCP of the 9 bins that have become standard ranges from 30% to 70% depending on optical depth. While the ISCCP simulator improved the agreement of cloud-top pressure between ground-based remote sensors and satellite observations, we find minor discrepancies due to the parameterization of cloud top pressure in the ISCCP simulator. The primary source of error seems to be related to discrepancies in visible optical depth that are not accounted for in the ISCCP simulator. We show that the optical depth discrepancies are largest when the assumptions necessary for plane parallel radiative transfer optical depths retrievals are violated.

  4. Evaluation of satellite soil moisture products over Norway using ground-based observations

    Science.gov (United States)

    Griesfeller, A.; Lahoz, W. A.; Jeu, R. A. M. de; Dorigo, W.; Haugen, L. E.; Svendby, T. M.; Wagner, W.

    2016-03-01

    In this study we evaluate satellite soil moisture products from the advanced SCATterometer (ASCAT) and the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) over Norway using ground-based observations from the Norwegian water resources and energy directorate. The ASCAT data are produced using the change detection approach of Wagner et al. (1999), and the AMSR-E data are produced using the VUA-NASA algorithm (Owe et al., 2001, 2008). Although satellite and ground-based soil moisture data for Norway have been available for several years, hitherto, such an evaluation has not been performed. This is partly because satellite measurements of soil moisture over Norway are complicated owing to the presence of snow, ice, water bodies, orography, rocks, and a very high coastline-to-area ratio. This work extends the European areas over which satellite soil moisture is validated to the Nordic regions. Owing to the challenging conditions for soil moisture measurements over Norway, the work described in this paper provides a stringent test of the capabilities of satellite sensors to measure soil moisture remotely. We show that the satellite and in situ data agree well, with averaged correlation (R) values of 0.72 and 0.68 for ASCAT descending and ascending data vs in situ data, and 0.64 and 0.52 for AMSR-E descending and ascending data vs in situ data for the summer/autumn season (1 June-15 October), over a period of 3 years (2009-2011). This level of agreement indicates that, generally, the ASCAT and AMSR-E soil moisture products over Norway have high quality, and would be useful for various applications, including land surface monitoring, weather forecasting, hydrological modelling, and climate studies. The increasing emphasis on coupled approaches to study the earth system, including the interactions between the land surface and the atmosphere, will benefit from the availability of validated and improved soil moisture satellite datasets, including those

  5. Spectral fine structure of the atomic ground states based on full relativistic theory

    Institute of Scientific and Technical Information of China (English)

    Zhenghe Zhu; Yongjian Tang

    2011-01-01

    @@ We focus on the full relativistic quantum mechanical calculations from boron to fluorine atoms with electronic configuration of 1s22s22pn (n = 1, 2, 3, 4, and 5), where 1s22s2 is the closed shell and 2pn is the open shell. Their active electrons in the open shell occupy all the six spinors as far as possible.Therefore, we suggest a new rule called "maximum probability" for the full symmetry group relativistic theory. Furthermore, the spectral fine structure of the atomic ground states based on the full relativistic theory and their intervals of L-S splitting are all reasonable. It is impossible to calculate the L-S splitting through non-relativistic quantum mechanics. The relativistic effect of atomic mass is increased significantly by about 12 folds from boron atom to fluorine atom.%We focus on the full relativistic quantum mechanical calculations from boron to fluorine atoms with electronic configuration of 1s22s22pn (n = 1, 2, 3, 4, and 5), where 1s22s2 is the closed shell and 2pn is the open shell. Their active electrons in the open shell occupy all the six spinors as far as possible.Therefore, we suggest a new rule called "maximum probability" for the full symmetry group relativistic theory. Furthermore, the spectral fine structure of the atomic ground states based on the full relativistic theory and their intervals of L-S splitting are all reasonable. It is impossible to calculate the L-S splitting through non-relativistic quantum mechanics. The relativistic effect of atomic mass is increased significantly by about 12 folds from boron atom to fluorine atom.

  6. Microwave signatures of ice hydrometeors from ground-based observations above Summit, Greenland

    Directory of Open Access Journals (Sweden)

    C. Pettersen

    2015-12-01

    Full Text Available Multi-instrument, ground-based measurements provide unique and comprehensive datasets of the atmosphere for a specific location over long periods of time and resulting data compliments past and existing global satellite observations. This paper explores the effect of ice hydrometeors on ground-based, high frequency passive microwave measurements and attempts to isolate an ice signature for summer seasons at Summit, Greenland from 2010–2013. Data from a combination of passive microwave, cloud radar, radiosonde, and ceilometer were examined to isolate the ice signature at microwave wavelengths. By limiting the study to a cloud liquid water path of 40 g m−2 or less, the cloud radar can identify cases where the precipitation was dominated by ice. These cases were examined using liquid water and gas microwave absorption models, and brightness temperatures were calculated for the high frequency microwave channels: 90, 150, and 225 GHz. By comparing the measured brightness temperatures from the microwave radiometers and the calculated brightness temperature using only gas and liquid contributions, any residual brightness temperature difference is due to emission and scattering of microwave radiation from the ice hydrometeors in the column. The ice signature in the 90, 150, and 225 GHz channels for the Summit Station summer months was isolated. This measured ice signature was then compared to an equivalent brightness temperature difference calculated with a radiative transfer model including microwave single scattering properties for several ice habits. Initial model results compare well against the four years of summer season isolated ice signature in the high-frequency microwave channels.

  7. Nutritional status assessment in semiclosed environments: ground-based and space flight studies in humans

    Science.gov (United States)

    Smith, S. M.; Davis-Street, J. E.; Rice, B. L.; Nillen, J. L.; Gillman, P. L.; Block, G.

    2001-01-01

    Adequate nutrition is critical during long-term spaceflight, as is the ability to easily monitor dietary intake. A comprehensive nutritional status assessment profile was designed for use before, during and after flight. It included assessment of both dietary intake and biochemical markers of nutritional status. A spaceflight food-frequency questionnaire (FFQ) was developed to evaluate intake of key nutrients during spaceflight. The nutritional status assessment protocol was evaluated during two ground-based closed-chamber studies (60 and 91 d; n = 4/study), and was implemented for two astronauts during 4-mo stays on the Mir space station. Ground-based studies indicated that the FFQ, administered daily or weekly, adequately estimated intake of key nutrients. Chamber subjects maintained prechamber energy intake and body weight. Astronauts tended to eat 40--50% of WHO-predicted energy requirements, and lost >10% of preflight body mass. Serum ferritin levels were lower after the chamber stays, despite adequate iron intake. Red blood cell folate concentrations were increased after the chamber studies. Vitamin D stores were decreased by > 40% on chamber egress and after spaceflight. Mir crew members had decreased levels of most nutritional indices, but these are difficult to interpret given the insufficient energy intake and loss of body mass. Spaceflight food systems can provide adequate intake of macronutrients, although, as expected, micronutrient intake is a concern for any closed or semiclosed food system. These data demonstrate the utility and importance of nutritional status assessment during spaceflight and of the FFQ during extended-duration spaceflight.

  8. Issues for Simulation of Galactic Cosmic Ray Exposures for Radiobiological Research at Ground Based Accelerators

    Directory of Open Access Journals (Sweden)

    Myung-Hee Y Kim

    2015-06-01

    Full Text Available For research on the health risks of galactic cosmic rays (GCR ground-based accelerators have been used for radiobiology research with mono-energetic beams of single high charge, Z and energy, E (HZE particles. In this paper we consider the pros and cons of a GCR reference field at a particle accelerator. At the NASA Space Radiation Laboratory (NSRL we have proposed a GCR simulator, which implements a new rapid switching mode and higher energy beam extraction to 1.5 GeV/u, in order to integrate multiple ions into a single simulation within hours or longer for chronic exposures. After considering the GCR environment and energy limitations of NSRL, we performed extensive simulation studies using the stochastic transport code, GERMcode (GCR Event Risk Model to define a GCR reference field using 9 HZE particle beam-energy combinations each with a unique absorber thickness to provide fragmentation and 10 or more energies of proton and 4He beams. The reference field is shown to well represent the charge dependence of GCR dose in several energy bins behind shielding compared to a simulated GCR environment. However a more significant challenge for space radiobiology research is to consider chronic GCR exposure of up to 3 years in relation to simulations with animal models of human risks. We discuss issues in approaches to map important biological time scales in experimental models using ground-based simulation with extended exposure of up to a few weeks using chronic or fractionation exposures. A kinetics model of HZE particle hit probabilities suggests that experimental simulations of several weeks will be needed to avoid high fluence rate artifacts, which places limitations on the experiments to be performed. Ultimately risk estimates are limited by theoretical understanding, and focus on improving understanding of mechanisms and development of experimental models to improve this understanding should remain the highest priority for space radiobiology

  9. Mesospheric CO above Troll station, Antarctica observed by a ground based microwave radiometer

    Directory of Open Access Journals (Sweden)

    C. Straub

    2013-01-01

    Full Text Available This paper presents mesospheric carbon monoxide (CO data acquired by the ground-based microwave radiometer of the British Antarctic Survey (BAS radiometer stationed at Troll station in Antarctica (72° S, 2.5° E, 1270 a.m.s.l.. The data set covers the period from February 2008 to January 2010, however, due to very low CO concentrations below approximately 80 km altitude in summer, profiles can only be retrieved during Antarctic winter. CO is measured for approximately 2 h each day and profiles are retrieved approximately every half hour. The retrieved profiles, covering the pressure range from 1 to 0.01 hPa (approximately 48 to 80 km, are compared to measurements from Aura/MLS and SD-WACCM. This intercomparison reveals a low bias of 0.5 to 1 ppmv at 0.1 hPa (approximately 64 km and 2.5 to 3.5 ppmv at 0.01 hPa (approximately 80 km of the BAS microwave radiometer compared to both reference datasets. One explanation for this low bias could be the known high bias of MLS which is in the same order of magnitude. The ground based radiometer shows high and significant correlation (coefficients higher than 0.9/0.65 compared to MLS/SD-WACCM at all altitudes compared with both reference datasets. doi:10.5285/DE3E2092-406D-47A9-9205-3971A8DFB4A9

  10. Mesospheric CO above Troll station, Antarctica observed by a ground based microwave radiometer

    Directory of Open Access Journals (Sweden)

    C. Straub

    2013-06-01

    Full Text Available This paper presents mesospheric carbon monoxide (CO data acquired by the ground-based microwave radiometer of the British Antarctic Survey (BAS radiometer stationed at Troll station in Antarctica (72° S, 2.5° E, 1270 m a.s.l.. The dataset covers the period from February 2008 to January 2010, however, due to very low CO concentrations below approximately 80 km altitude in summer, profiles are only presented during the Antarctic winter. CO is measured for approximately 2 h each day and profiles are retrieved approximately every half hour. The retrieved profiles, covering the pressure range from 1 to 0.01 hPa (approximately 48 to 80 km, are compared to measurements from Microwave Limb Sounder on the Aura satellite (Aura/MLS and Whole Atmosphere Community Climate Model with Specified Dynamics (SD-WACCM. This intercomparison reveals a low bias of 0.5 to 1 ppmv at 0.1 hPa (approximately 64 km and 2.5 to 3.5 ppmv at 0.01 hPa (approximately 80 km of the BAS microwave radiometer compared to both reference datasets. One explanation for this low bias could be the known high bias of MLS which is on the same order of magnitude. The ground based radiometer shows high and significant correlation (coefficients higher than 0.9/0.7 compared to MLS/SD-WACCM at all altitudes compared with both reference datasets. The dataset can be accessed under http://dx.doi.org/10/mhq.

  11. High Resolution Spectral Analysis of Hiss and Chorus Emissions in Ground Based Data

    Science.gov (United States)

    Hosseini Aliabad, S. P.; Golkowski, M.; Gibby, A. R.

    2015-12-01

    The dynamic evolution of the radiation belts is believed to be controlled in large part by two separate but related classes of naturally occurring plasma waves: ELF/VLF chorus and hiss emissions. Although whistler mode chorus has been extensively studied since the first reports by Storey in 1953, the source mechanism and properties are still subjects of active research. Moreover, the origin of plasmaspheric hiss, the electromagnetic emission believed to be responsible for the gap between the inner and outer radiation belts, has been debated for over four decades. Although these waves can be observed in situ on spacecraft, ground-based observing stations can provide orders of magnitude higher data volumes and decades long data coverage essential for certain long-term and statistical studies of wave properties. Recent observational and theoretical works suggest that high resolution analysis of the spectral features of both hiss and chorus emissions can provide insight into generation processes and be used to validate existing theories. Application of the classic Fourier (FFT) technique unfortunately yields a tradeoff between time and frequency resolution. In additional to Fourier spectra, we employ novel methods to make spectrograms with high time and frequency resolutions, independently using minimum variance distortionless response (MVDR). These techniques are applied to ground based data observations of hiss and chorus made in Alaska. Plasmaspheric hiss has been widely regarded as a broadband, structure less, incoherent emission. We quantify the extent to which plasmaspheric hiss can be a coherent emission with complex fine structure. Likewise, to date, researchers have differentiated between hiss and chorus coherency primarily using qualitative "naked eye" approaches to amplitude spectra. Using a quantitative approach to observed amplitude and we present more rigorous classification criteria for these emissions.

  12. Geocenter Coordinates from a Combined Processing of LEO and Ground-based GPS Observations

    Science.gov (United States)

    Männel, Benjamin; Rothacher, Markus

    2017-04-01

    The GPS observations provided by the global IGS (International GNSS Service) tracking network play an important role for the realization of a unique terrestrial reference frame that is accurate enough to allow the monitoring of the Earth's system. Combining these ground-based data with GPS observations tracked by high-quality dual-frequency receivers on-board Low Earth Orbiters (LEO) might help to further improve the realization of the terrestrial reference frame and the estimation of the geocenter coordinates, GPS satellite orbits and Earth rotation parameters (ERP). To assess the scope of improvement, we processed a network of 50 globally distributed and stable IGS-stations together with four LEOs (GRACE-A, GRACE-B, OSTM/Jason-2 and GOCE) over a time interval of three years (2010-2012). To ensure fully consistent solutions the zero-difference phase observations of the ground stations and LEOs were processed in a common least-square adjustment, estimating GPS orbits, LEO orbits, station coordinates, ERPs, site-specific tropospheric delays, satellite and receiver clocks and ambiguities. We present the significant impact of the individual LEOs and a combination of all four LEOs on geocenter coordinates derived by using a translational approach (also called network shift approach). In addition, we present geocenter coordinates derived from the same set of GPS observations by using a unified approach. This approach combines the translational and the degree-one approach by estimating translations and surface deformations simultaneously. Based on comparisons against each other and against geocenter time series derived by other techniques the effect of the selected approach is assessed.

  13. Proteomic and Epigenetic Analysis of Rice after Seed Spaceflight and Ground-Base Ion Radiations

    Science.gov (United States)

    Wang, Wei; Sun, Yeqing; Peng, Yuming; Zhao, Qian; Wen, Bin; Yang, Jun

    Highly ionizing radiation (HZE) in space is considered as main factor causing biological effects to plant seeds. In previous work, we compared the proteomic profiles of rice plants growing after seed spaceflights to ground controls by two-dimensional difference gel electrophoresis (2-D DIGE) with mass spectrometry and found that the protein expression profiles were changed and differentially expressed proteins participated in most of the biological processes of rice. To further evaluate the dosage effects of space radiation and compare between low- and high-dose ion effects, we carried out three independent ground-base ionizing radiation experiments with different cumulative doses (low-dose range: 2~1000mGy, high-dose range: 2000~20000mGy) to rice seeds and performed proteomic analysis of seedlings. We found that protein expression profiles showed obvious boundaries between low- and high-dose radiation groups. Rates of differentially expressed proteins presented a dose-dependent effect, it reached the highest value at 2000mGy dosage point in all three radiation experiments coincidently; while proteins responded to low-dose radiations preferred to change their expressions at the minimum dosage (2mGy). Proteins participating in rice biological processes also responded differently between low- and high-dose radiations: proteins involved in energy metabolism and photosynthesis tended to be regulated after low-dose radiations while stress responding, protein folding and cell redox homeostasis related proteins preferred to change their expressions after high-dose radiations. By comparing the proteomic profiles between ground-base radiations and spaceflights, it was worth noting that ground-base low-dose ion radiation effects shared similar biological effects as space environment. In addition, we discovered that protein nucleoside diphosphate kinase 1 (NDPK1) showed obvious increased regulation after spaceflights and ion radiations. NDPK1 catalyzes nucleotide metabolism

  14. Sub-Seasonal Variability of Tropical Rainfall Observed by TRMM and Ground-based Polarimetric Radar

    Science.gov (United States)

    Dolan, Brenda; Rutledge, Steven; Lang, Timothy; Cifelli, Robert; Nesbitt, Stephen

    2010-05-01

    Studies of tropical precipitation characteristics from the TRMM-LBA and NAME field campaigns using ground-based polarimetric S-band data have revealed significant differences in microphysical processes occurring in the various meteorological regimes sampled in those projects. In TRMM-LMA (January-February 1999 in Brazil; a TRMM ground validation experiment), variability is driven by prevailing low-level winds. During periods of low-level easterlies, deeper and more intense convection is observed, while during periods of low-level westerlies, weaker convection embedded in widespread stratiform precipitation is common. In the NAME region (North American Monsoon Experiment, summer 2004 along the west coast of Mexico), strong terrain variability drives differences in precipitation, with larger drops and larger ice mass aloft associated with convection occurring over the coastal plain compared to convection over the higher terrain of the Sierra Madre Occidental, or adjacent coastal waters. Comparisons with the TRMM precipitation radar (PR) indicate that such sub-seasonal variability in these two regions are not well characterized by the TRMM PR reflectivity and rainfall statistics. TRMM PR reflectivity profiles in the LBA region are somewhat lower than S-Pol values, particularly in the more intense easterly regime convection. In NAME, mean reflectivities are even more divergent, with TRMM profiles below those of S-Pol. In both regions, the TRMM PR does not capture rain rates above 80 mm hr-1 despite much higher rain rates estimated from the S-Pol polarimetric data, and rain rates are generally lower for a given reflectivity from TRMM PR compared to S-Pol. These differences between TRMM PR and S-Pol may arise from the inability of Z-R relationships to capture the full variability of microphysical conditions or may highlight problems with TRMM retrievals over land. In addition to the TRMM-LBA and NAME regions, analysis of sub-seasonal precipitation variability and

  15. Ground-based aerosol characterization during the South American Biomass Burning Analysis (SAMBBA) field experiment

    Science.gov (United States)

    Brito, J.; Rizzo, L. V.; Morgan, W. T.; Coe, H.; Johnson, B.; Haywood, J.; Longo, K.; Freitas, S.; Andreae, M. O.; Artaxo, P.

    2014-11-01

    This paper investigates the physical and chemical characteristics of aerosols at ground level at a site heavily impacted by biomass burning. The site is located near Porto Velho, Rondônia, in the southwestern part of the Brazilian Amazon rainforest, and was selected for the deployment of a large suite of instruments, among them an Aerosol Chemical Speciation Monitor. Our measurements were made during the South American Biomass Burning Analysis (SAMBBA) field experiment, which consisted of a combination of aircraft and ground-based measurements over Brazil, aimed to investigate the impacts of biomass burning emissions on climate, air quality, and numerical weather prediction over South America. The campaign took place during the dry season and the transition to the wet season in September/October 2012. During most of the campaign, the site was impacted by regional biomass burning pollution (average CO mixing ratio of 0.6 ppm), occasionally superimposed by intense (up to 2 ppm of CO), freshly emitted biomass burning plumes. Aerosol number concentrations ranged from ~1000 cm-3 to peaks of up to 35 000 cm-3 (during biomass burning (BB) events, corresponding to an average submicron mass mean concentrations of 13.7 μg m-3 and peak concentrations close to 100 μg m-3. Organic aerosol strongly dominated the submicron non-refractory composition, with an average concentration of 11.4 μg m-3. The inorganic species, NH4, SO4, NO3, and Cl, were observed, on average, at concentrations of 0.44, 0.34, 0.19, and 0.01 μg m-3, respectively. Equivalent black carbon (BCe) ranged from 0.2 to 5.5 μg m-3, with an average concentration of 1.3 μg m-3. During BB peaks, organics accounted for over 90% of total mass (submicron non-refractory plus BCe), among the highest values described in the literature. We examined the ageing of biomass burning organic aerosol (BBOA) using the changes in the H : C and O : C ratios, and found that throughout most of the aerosol processing (O : C ≅ 0

  16. Ground based aerosol characterization during the South American Biomass Burning Analysis (SAMBBA field experiment

    Directory of Open Access Journals (Sweden)

    J. Brito

    2014-05-01

    Full Text Available This paper investigates the physical and chemical characteristics of aerosols at ground level at a site heavily impacted by biomass burning. The site is located near Porto Velho, Rondônia, in the Southwestern part of the Brazilian Amazon forest, and was selected for the deployment of a large suite of instruments, among them an Aerosol Chemical Speciation Monitor. Our measurements were made during the South American Biomass Burning Analysis (SAMBBA field experiment, which consisted of a combination of aircraft and ground based measurements over Brazil, aiming to investigate the impacts of biomass burning emissions on climate, air quality, and numerical weather prediction over South America. The campaign took place during the dry season and the transition to the wet season in September/October 2012. During most of the campaign, the site was impacted by regional biomass burning pollution (average CO mixing ratio of 0.6 ppm, occasionally superimposed by intense (up to 2 ppm of CO, freshly emitted biomass burning plumes. Aerosol number concentrations ranged from ∼1000 cm−3 to peaks of up to 35 000 cm−3 during biomass burning (BB events, corresponding to an average submicron mass mean concentrations of 13.7 μg m−3 and peak concentrations close to 100 μg m−3. Organic aerosol strongly dominated the submicron non-refractory composition, with an average concentration of 11.4 μg m−3. The inorganic species, NH4, SO4, NO3, and Cl, were observed on average at concentrations of 0.44, 0.34, 0.19, and 0.01 μg m−3, respectively. Equivalent Black Carbon (BCe ranged from 0.2 to 5.5 μg m−3, with an average concentration of 1.3 μg m−3. During BB peaks, organics accounted for over 90% of total mass (submicron non-refractory plus BCe, among the highest values described in the literature. We examined the ageing of Biomass Burning Organic Aerosol (BBOA using the changes in the H : C and O : C ratios, and found that throughout most of the aerosol

  17. Robust Ground Target Detection by SAR and IR Sensor Fusion Using Adaboost-Based Feature Selection.

    Science.gov (United States)

    Kim, Sungho; Song, Woo-Jin; Kim, So-Hyun

    2016-07-19

    Long-range ground targets are difficult to detect in a noisy cluttered environment using either synthetic aperture radar (SAR) images or infrared (IR) images. SAR-based detectors can provide a high detection rate with a high false alarm rate to background scatter noise. IR-based approaches can detect hot targets but are affected strongly by the weather conditions. This paper proposes a novel target detection method by decision-level SAR and IR fusion using an Adaboost-based machine learning scheme to achieve a high detection rate and low false alarm rate. The proposed method consists of individual detection, registration, and fusion architecture. This paper presents a single framework of a SAR and IR target detection method using modified Boolean map visual theory (modBMVT) and feature-selection based fusion. Previous methods applied different algorithms to detect SAR and IR targets because of the different physical image characteristics. One method that is optimized for IR target detection produces unsuccessful results in SAR target detection. This study examined the image characteristics and proposed a unified SAR and IR target detection method by inserting a median local average filter (MLAF, pre-filter) and an asymmetric morphological closing filter (AMCF, post-filter) into the BMVT. The original BMVT was optimized to detect small infrared targets. The proposed modBMVT can remove the thermal and scatter noise by the MLAF and detect extended targets by attaching the AMCF after the BMVT. Heterogeneous SAR and IR images were registered automatically using the proposed RANdom SAmple Region Consensus (RANSARC)-based homography optimization after a brute-force correspondence search using the detected target centers and regions. The final targets were detected by feature-selection based sensor fusion using Adaboost. The proposed method showed good SAR and IR target detection performance through feature selection-based decision fusion on a synthetic database generated

  18. Robust Ground Target Detection by SAR and IR Sensor Fusion Using Adaboost-Based Feature Selection

    Directory of Open Access Journals (Sweden)

    Sungho Kim

    2016-07-01

    Full Text Available Long-range ground targets are difficult to detect in a noisy cluttered environment using either synthetic aperture radar (SAR images or infrared (IR images. SAR-based detectors can provide a high detection rate with a high false alarm rate to background scatter noise. IR-based approaches can detect hot targets but are affected strongly by the weather conditions. This paper proposes a novel target detection method by decision-level SAR and IR fusion using an Adaboost-based machine learning scheme to achieve a high detection rate and low false alarm rate. The proposed method consists of individual detection, registration, and fusion architecture. This paper presents a single framework of a SAR and IR target detection method using modified Boolean map visual theory (modBMVT and feature-selection based fusion. Previous methods applied different algorithms to detect SAR and IR targets because of the different physical image characteristics. One method that is optimized for IR target detection produces unsuccessful results in SAR target detection. This study examined the image characteristics and proposed a unified SAR and IR target detection method by inserting a median local average filter (MLAF, pre-filter and an asymmetric morphological closing filter (AMCF, post-filter into the BMVT. The original BMVT was optimized to detect small infrared targets. The proposed modBMVT can remove the thermal and scatter noise by the MLAF and detect extended targets by attaching the AMCF after the BMVT. Heterogeneous SAR and IR images were registered automatically using the proposed RANdom SAmple Region Consensus (RANSARC-based homography optimization after a brute-force correspondence search using the detected target centers and regions. The final targets were detected by feature-selection based sensor fusion using Adaboost. The proposed method showed good SAR and IR target detection performance through feature selection-based decision fusion on a synthetic

  19. Assessment of NASA Airborne Laser Altimetry Data Using Ground-Based GPS Data near Summit Station, Greenland

    Science.gov (United States)

    Brunt, Kelly M.; Hawley, Robert L.; Lutz, Eric R.; Studinger, Michael; Sonntag, John G.; Hofton, Michelle A.; Andrews, Lauren C.; Neumann, Thomas A.

    2017-01-01

    A series of NASA airborne lidars have been used in support of satellite laser altimetry missions. These airbornelaser altimeters have been deployed for satellite instrument development, for spaceborne data validation, and to bridge the data gap between satellite missions. We used data from ground-based Global Positioning System (GPS) surveys of an 11 km long track near Summit Station, Greenland, to assess the surface elevation bias and measurement precision of three airborne laser altimeters including the Airborne Topographic Mapper (ATM), the Land, Vegetation, and Ice Sensor (LVIS), and the Multiple Altimeter Beam Experimental Lidar (MABEL). Ground-based GPS data from the monthly ground-based traverses, which commenced in 2006, allowed for the assessment of nine airborne lidar surveys associated with ATM and LVIS between 2007 and 2016. Surface elevation biases for these altimeters over the flat, ice-sheet interior are less than 0.12 m, while assessments of measurement precision are 0.09 m or better. Ground-based GPS positions determined both with and without differential post-processing techniques provided internally consistent solutions. Results from the analyses of ground-based and airborne data provide validation strategy guidance for the Ice, Cloud, and land Elevation Satellite 2 (ICESat-2) elevation and elevation-change data products.

  20. An Efficient approach for Shielding Effect of the Grounding Electrodes under Impulse-Current Voltage based on MATLAB

    Directory of Open Access Journals (Sweden)

    Kalyani Pole

    2012-06-01

    Full Text Available The lightning current waveform has a major influence on the dynamic performance of ground electrodes. While high lightning current intensity improves the dynamic grounding performance due to ionization of the soil, very fast fronted pulses might worsen the performance in case of inductive behaviour. The previous analysis has often been based on quasistatic approximation that is not applicable to very fast fronted pulses. Previous Research focused on analyzing the impulse current dispersal regularity of different branches when injecting at one point. Comparing with the leakage current distribution of a single ground electrode, it is found that the leakage currents along the branches increase with the distance to the current feed point, and the more conductors near the injection point, the more uneven the leakage current distribution is. In this paper by simulation result we indicate that shielding effect should be taken into account when analyzing the impulse characteristics of grounding electrodes. Based on the simulation results, new empirical formulas applicable for slow and very fast fronted lightning current pulses are proposed. The effects of the ionization of the soil are disregarded; therefore, the new formulas are applicable for a conservative estimate of the upper bound of the impulse impedance of ground electrodes. In this paper we also analyze and compare by the MATLAB. We also provide dynamic behavior of ground electrodes.

  1. Comparing distinct ground-based lightning location networks covering the Netherlands

    Science.gov (United States)

    de Vos, Lotte; Leijnse, Hidde; Schmeits, Maurice; Beekhuis, Hans; Poelman, Dieter; Evers, Läslo; Smets, Pieter

    2015-04-01

    Lightning can be detected using a ground-based sensor network. The Royal Netherlands Meteorological Institute (KNMI) monitors lightning activity in the Netherlands with the so-called FLITS-system; a network combining SAFIR-type sensors. This makes use of Very High Frequency (VHF) as well as Low Frequency (LF) sensors. KNMI has recently decided to replace FLITS by data from a sub-continental network operated by Météorage which makes use of LF sensors only (KNMI Lightning Detection Network, or KLDN). KLDN is compared to the FLITS system, as well as Met Office's long-range Arrival Time Difference (ATDnet), which measures Very Low Frequency (VLF). Special focus lies on the ability to detect Cloud to Ground (CG) and Cloud to Cloud (CC) lightning in the Netherlands. Relative detection efficiency of individual flashes and lightning activity in a more general sense are calculated over a period of almost 5 years. Additionally, the detection efficiency of each system is compared to a ground-truth that is constructed from flashes that are detected by both of the other datasets. Finally, infrasound data is used as a fourth lightning data source for several case studies. Relative performance is found to vary strongly with location and time. As expected, it is found that FLITS detects significantly more CC lightning (because of the strong aptitude of VHF antennas to detect CC), though KLDN and ATDnet detect more CG lightning. We analyze statistics computed over the entire 5-year period, where we look at CG as well as total lightning (CC and CG combined). Statistics that are considered are the Probability of Detection (POD) and the so-called Lightning Activity Detection (LAD). POD is defined as the percentage of reference flashes the system detects compared to the total detections in the reference. LAD is defined as the fraction of system recordings of one or more flashes in predefined area boxes over a certain time period given the fact that the reference detects at least one

  2. A ground-based near-infrared emission spectrum of the exoplanet HD 189733b.

    Science.gov (United States)

    Swain, Mark R; Deroo, Pieter; Griffith, Caitlin A; Tinetti, Giovanna; Thatte, Azam; Vasisht, Gautam; Chen, Pin; Bouwman, Jeroen; Crossfield, Ian J; Angerhausen, Daniel; Afonso, Cristina; Henning, Thomas

    2010-02-01

    Detection of molecules using infrared spectroscopy probes the conditions and compositions of exoplanet atmospheres. Water (H(2)O), methane (CH(4)), carbon dioxide (CO(2)), and carbon monoxide (CO) have been detected in two hot Jupiters. These previous results relied on space-based telescopes that do not provide spectroscopic capability in the 2.4-5.2 microm spectral region. Here we report ground-based observations of the dayside emission spectrum for HD 189733b between 2.0-2.4 microm and 3.1-4.1 microm, where we find a bright emission feature. Where overlap with space-based instruments exists, our results are in excellent agreement with previous measurements. A feature at approximately 3.25 microm is unexpected and difficult to explain with models that assume local thermodynamic equilibrium (LTE) conditions at the 1 bar to 1 x 10(-6) bar pressures typically sampled by infrared measurements. The most likely explanation for this feature is that it arises from non-LTE emission from CH(4), similar to what is seen in the atmospheres of planets in our own Solar System. These results suggest that non-LTE effects may need to be considered when interpreting measurements of strongly irradiated exoplanets.

  3. Simulated forecasts for primordial B-mode searches in ground-based experiments

    CERN Document Server

    Alonso, David; Naess, Sigurd; Thorne, Ben

    2016-01-01

    Detecting the imprint of inflationary gravitational waves on the $B$-mode polarization of the Cosmic Microwave Background (CMB) is one of the main science cases for current and next-generation CMB experiments. In this work we explore some of the challenges that ground-based facilities will have to face in order to carry out this measurement in the presence of Galactic foregrounds and correlated atmospheric noise. We present forecasts for Stage-3 (S3) and planned Stage-4 (S4) experiments based on the analysis of simulated sky maps using a map-based Bayesian foreground cleaning method. Our results thus consistently propagate the uncertainties on foreground parameters such as spatially-varying spectral indices, as well as the bias on the measured tensor-to-scalar ratio $r$ caused by an incorrect modelling of the foregrounds. We find that S3 and S4-like experiments should be able to put constraints on $r$ of the order $\\sigma(r)=(0.5-1.0)\\times10^{-2}$ and $\\sigma(r)=(0.5-1.0)\\times10^{-3}$ respectively, assuming...

  4. Evaluation of Satellite and Ground Based Precipitation Products for Flood Forecasting

    Science.gov (United States)

    Chintalapudi, S.; Sharif, H.; Yeggina, S.

    2012-04-01

    The development in satellite-derived rainfall estimates encouraged the hydrological modeling in sparse gauged basins or ungauged basins. Especially, physically-based distributed hydrological models can benefit from the good spatial and temporal coverage of satellite precipitation products. In this study, three satellite derived precipitation datasets (TRMM, CMORPH, and PERSIANN), NEXRAD, and rain gauge precipitation datasets were used to drive the hydrological model. The physically-based, distributed hydrological model Gridded Surface Subsurface Hydrological Analysis (GSSHA) was used in this study. Focus will be on the results from the Guadalupe River Basin above Canyon Lake and below Comfort, Texas. The Guadalupe River Basin above Canyon Lake and below Comfort Texas drains an area of 1232 km2. Different storm events will be used in these simulations. August 2007 event was used as calibration and June 2007 event was used as validation. Results are discussed interms of accuracy of satellite precipitation estimates with the ground based precipitation estimates, predicting peak discharges, runoff volumes, time lag, and spatial distribution. The initial results showed that, model was able to predict the peak discharges and runoff volumes when using NEXRAD MPE data, and TRMM 3B42 precipitation product. The results also showed that there was time lag in hydrographs driven by both PERSIANN and CMORPH data sets.

  5. Simulated forecasts for primordial B -mode searches in ground-based experiments

    Science.gov (United States)

    Alonso, David; Dunkley, Joanna; Thorne, Ben; Næss, Sigurd

    2017-02-01

    Detecting the imprint of inflationary gravitational waves on the B -mode polarization of the cosmic microwave background (CMB) is one of the main science cases for current and next-generation CMB experiments. In this work we explore some of the challenges that ground-based facilities will have to face in order to carry out this measurement in the presence of galactic foregrounds and correlated atmospheric noise. We present forecasts for stage-3 (S3) and planned stage-4 (S4) experiments based on the analysis of simulated sky maps using a map-based Bayesian foreground-cleaning method. Our results thus consistently propagate the uncertainties on foreground parameters such as spatially varying spectral indices, as well as the bias on the measured tensor-to-scalar ratio r caused by an incorrect modeling of the foregrounds. We find that S3 and S4-like experiments should be able to put constraints on r of the order σ (r )=(0.5 - 1.0 )×10-2 and σ (r )=(0.5 - 1.0 )×10-3 respectively, assuming instrumental systematic effects are under control. We further study deviations from the fiducial foreground model, finding that, while the effects of a second polarized dust component would be minimal on both S3 and S4, a 2% polarized anomalous dust emission component would be clearly detectable by stage-4 experiments.

  6. Altitudinal variation of midlatitude localized TEC enhancement from ground- and space-based measurements

    Science.gov (United States)

    Datta-Barua, S.; Mannucci, A. J.; Walter, T.; Enge, P.

    2008-10-01

    We present terrestrial and space-based dual-frequency observations of a region of enhanced total electron content (TEC) over the southeastern United States at local nighttime during the geomagnetic storm of 29-31 October 2003. The apparently localized, large-amplitude, and nearly Earth-fixed midlatitude ionosphere disturbance contained about 10 m higher delay at Global Positioning System (GPS) L1 frequency than the nighttime background ionosphere TEC. Using the dual-frequency altimeter on board the Jason satellite, we show evidence that nearly all of the electron content was below its orbital altitude of 1300 km at 0000 local time on 31 October 2003. Dual frequency GPS measurements from the receiver on board the SAC-C satellite indicate that some portion of the electron content existed above the 700 km orbit altitude of SAC-C. We develop a horizontally piecewise constant regional model of the enhancement. We compare the model prediction of TEC with the SAC-C satellite GPS data to constrain the altitude of this enhanced TEC region. Our model indicates that the peak density of the anomalous region is at slightly higher altitude and greater in amplitude than that of the background. The TEC enhancement provides a concrete case study of an extreme scenario that both space-based and ground-based GPS augmentation systems must take into account in order to offer high-accuracy, high-integrity corrections to GPS for safety-of-life applications.

  7. A ground-based near-infrared emission spectrum of the exoplanet HD 189733b

    CERN Document Server

    Swain, Mark R; Griffith, Caitlin A; Tinetti, Giovanna; Thatte, Azam; Vasisht, Gautam; Chen, Pin; Bouwman, Jeroen; Crossfield, Ian J; Angerhausen, Daniel; Afonso, Cristina; Henning, Thomas

    2010-01-01

    Detection of molecules using infrared spectroscopy probes the conditions and compositions of exoplanet atmospheres. Water (H2O), methane (CH4), carbon dioxide (CO2), and carbon monoxide (CO) have been detected in two hot Jupiters. These previous results relied on space-based telescopes that do not provide spectroscopic capability in the 2.4 - 5.2 micron spectral region. Here we report ground-based observations of the dayside emission spectrum for HD 189733b between 2.0-2.4 micron and 3.1-4.1 micron, where we find a bright emission feature. Where overlap with space-based instruments exists, our results are in excellent agreement with previous measurements. A feature at ~3.25 micron is unexpected and difficult to explain with models that assume local thermodynamic equilibrium (LTE) conditions at the 1 bar to 1 x 10-6 bar pressures typically sampled by infrared measurements. The most likely explanation for this feature is that it arises from non-LTE emission from CH4, similar to what is seen in the atmospheres o...

  8. Low Frequency Gravitational Wave Detection With Ground Based Atom Interferometer Arrays

    CERN Document Server

    Chaibi, W; Canuel, B; Bertoldi, A; Landragin, A; Bouyer, P

    2016-01-01

    We propose a new detection strategy for gravitational waves (GWs) below few Hertz based on a correlated array of atom interferometers (AIs). Our proposal allows to reduce the Newtonian Noise (NN) which limits all ground based GW detectors below few Hertz, including previous atom interferometry-based concepts. Using an array of long baseline AI gradiometers yields several estimations of the NN, whose effect can thus be reduced via statistical averaging. Considering the km baseline of current optical detectors, a NN rejection of factor 2 could be achieved, and tested with existing AI array geometries. Exploiting the correlation properties of the gravity acceleration noise, we show that a 10-fold or more NN rejection is possible with a dedicated configuration. Considering a conservative NN model and the current developments in cold atom technology, we show that strain sensitivities below $1\\times 10^{-19}/ \\sqrt{\\text{Hz}}$ in the $ 0.3-3 \\ \\text{Hz}$ frequency band can be within reach, with a peak sensitivity o...

  9. Missile Defense: DOD’s Report Provides Limited Insight on Testing Options for the Ground-based Midcourse Defense System

    Science.gov (United States)

    2014-04-30

    Cochran Ranking Member Subcommittee on Defense Committee on Appropriations United States Senate The Honorable Howard P. " Buck " McKeon Chairman The...System Component Mission Location Ground Based Interceptor (GBI) The interceptor consists of a silo-based, three-stage booster stack and a “hit-to

  10. 3D visual analysis tool in support of the SANDF's growing ground based air defence simulation capability

    CSIR Research Space (South Africa)

    Duvenhage, B

    2007-10-01

    Full Text Available A 3D visual analysis tool has been developed to add value to the SANDF's growing Ground Based Air Defence (GBAD) System of Systems simulation capability. A time based XML interface between the simulation and analysis tool, via a TCP connection or a...

  11. Fault diagnosis in neutral point indirectly grounded system based on information fusion

    Institute of Scientific and Technical Information of China (English)

    于飞; 鞠丽叶; 刘喜梅; 崔平远; 钟秋海

    2003-01-01

    In neutral point indirectly grounded systems, phase-to-ground fault is putting new demands on fault diagnosis technology. Information fusion is applied to detect the phase-to-ground fault, which integrates several sources of information, including line current, line voltage, zero sequence current and voltage, and quintic harmonic wave component. This method is testified through the simulation of Matlab. Simulation results show that the precision and reliability of the detection has been greatly increased.

  12. Validation of VIIRS Cloud Base Heights at Night Using Ground and Satellite Measurements over Alaska

    Science.gov (United States)

    NOH, Y. J.; Miller, S. D.; Seaman, C.; Forsythe, J. M.; Brummer, R.; Lindsey, D. T.; Walther, A.; Heidinger, A. K.; Li, Y.

    2016-12-01

    Knowledge of Cloud Base Height (CBH) is critical to describing cloud radiative feedbacks in numerical models and is of practical significance to aviation communities. We have developed a new CBH algorithm constrained by Cloud Top Height (CTH) and Cloud Water Path (CWP) by performing a statistical analysis of A-Train satellite data. It includes an extinction-based method for thin cirrus. In the algorithm, cloud geometric thickness is derived with upstream CTH and CWP input and subtracted from CTH to generate the topmost layer CBH. The CBH information is a key parameter for an improved Cloud Cover/Layers product. The algorithm has been applied to the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the Suomi NPP spacecraft. Nighttime cloud optical properties for CWP are retrieved from the nighttime lunar cloud optical and microphysical properties (NLCOMP) algorithm based on a lunar reflectance model for the VIIRS Day/Night Band (DNB) measuring nighttime visible light such as moonlight. The DNB has innovative capabilities to fill the polar winter and nighttime gap of cloud observations which has been an important shortfall from conventional radiometers. The CBH products have been intensively evaluated against CloudSat data. The results showed the new algorithm yields significantly improved performance over the original VIIRS CBH algorithm. However, since CloudSat is now operational during daytime only due to a battery anomaly, the nighttime performance has not been fully assessed. This presentation will show our approach to assess the performance of the CBH algorithm at night. VIIRS CBHs are retrieved over the Alaska region from October 2015 to April 2016 using the Clouds from AVHRR Extended (CLAVR-x) processing system. Ground-based measurements from ceilometer and micropulse lidar at the Atmospheric Radiation Measurement (ARM) site on the North Slope of Alaska are used for the analysis. Local weather conditions are checked using temperature and precipitation

  13. Validation of CALIPSO space-borne-derived attenuated backscatter coefficient profiles using a ground-based lidar in Athens, Greece

    Directory of Open Access Journals (Sweden)

    R. E. Mamouri

    2009-09-01

    Full Text Available We present initial aerosol validation results of the space-borne lidar CALIOP -onboard the CALIPSO satellite- Level 1 attenuated backscatter coefficient profiles, using coincident observations performed with a ground-based lidar in Athens, Greece (37.9° N, 23.6° E. A multi-wavelength ground-based backscatter/Raman lidar system is operating since 2000 at the National Technical University of Athens (NTUA in the framework of the European Aerosol Research LIdar NETwork (EARLINET, the first lidar network for tropospheric aerosol studies on a continental scale. Since July 2006, a total of 40 coincidental aerosol ground-based lidar measurements were performed over Athens during CALIPSO overpasses. The ground-based measurements were performed each time CALIPSO overpasses the station location within a maximum distance of 100 km. The duration of the ground–based lidar measurements was approximately two hours, centred on the satellite overpass time. From the analysis of the ground-based/satellite correlative lidar measurements, a mean bias of the order of 22% for daytime measurements and of 8% for nighttime measurements with respect to the CALIPSO profiles was found for altitudes between 3 and 10 km. The mean bias becomes much larger for altitudes lower that 3 km (of the order of 60% which is attributed to the increase of aerosol horizontal inhomogeneity within the Planetary Boundary Layer, resulting to the observation of possibly different air masses by the two instruments. In cases of aerosol layers underlying Cirrus clouds, comparison results for aerosol tropospheric profiles become worse. This is attributed to the significant multiple scattering effects in Cirrus clouds experienced by CALIPSO which result in an attenuation which is less than that measured by the ground-based lidar.

  14. Operational impacts to residual stands following ground-based skidding in Hyrcanian Forest, northern Iran

    Institute of Scientific and Technical Information of China (English)

    Meghdad Jourgholami

    2012-01-01

    Hyrcanian (Caspian) Forest in northern Iran has a richness of biological diversity,with endemic and endangered species.The usage of ground-based skidding is well accepted practice for the extraction of timber from the forest,but this operation has tended to cause the greatest environmental problems.The aims of the study were to evaluate and comparison of operational impacts,residual stand damage,regeneration,and to quantify these effects such as:the extent of the damage,wounding patterns,size and distribution after logging operations that utilized two different methods:short-log and long-log.A Timberjack cable skidder was used and the study location was in the Kheyrud Forest.Post harvesting assessment of damage to the residual stand was compared along skid trail by 100% inventory method and also for the assessment of regeneration damage along winching strips.The results show that along winching strips the percentage of damage to the regeneration was 44% and 36%,while the tree damages along skid trails reached 2.3% and 4.1% in the short-log and long-log methods,respectively.The greatest average amount of damage to a bole occurred along the first 1 m up from the ground (97%) and also within 4 m of the skidder centerline (80%).These results show that the short-log method causes less damage to the residual stand than the long-log method.Tree location to skidder trail appears to have a significant effect on the number and height of scars on a tree.Well designed and constructed trails should he wide enough to allow wood extraction from the forest.Damage to the residual stand might be reduced by proper planning and training of logging crews.

  15. Cloud parameters using Ground Based Remote Sensing Systems and Satellites over urban coastal area

    Science.gov (United States)

    Han, Z. T.; Gross, B.; Moshary, F.; Wu, Y.; Ahmed, S. A.

    2013-12-01

    Determining cloud radiative and microphysical properties are very important as a means to assess their effect on earths energy balance. While MODIS and GOES have been used for estimating cloud properties, assessing cloud properties directly has been difficult due the lack of consistent ground based sensor measurements except in such established places such as the ARM site in Oklahoma. However, it is known that significant aerosol seeding from urban and/or maritime sources can modify cloud properties such as effective radius and cloud optical depth and therefore evaluation of satellite retrievals in such a unique area offers novel opportunities to assess the potential of satellite retrievals to distinguish these mechanisms In our study, we used a multi-filter rotating shadow band radiometer (MFRSR) and micro wave radiometer (MWR) to retrieve the cloud optical depth and cloud droplets effective radius . In particular, we make a statistical study during summer 2013 where water phase clouds dominate and assess the accuracy of both MODIS and GOES satellite cloud products including LWP, COD and Reff. Most importantly, we assess performance against satellite observing geometries. Much like previous studies at the ARM site, we observe significant biases in the effective radius when the solar zenith angle is too large. In addition, we show that biases are also sensitive to the LWP limiting such measurement s in assessing potential aerosol-cloud signatures Finally, we discuss preliminary aerosol-cloud interactions from our ground system where local lidar is used to assess aerosols below clouds and explore the Aerosol Cloud Index.

  16. Satellite Based Soil Moisture Product Validation Using NOAA-CREST Ground and L-Band Observations

    Science.gov (United States)

    Norouzi, H.; Campo, C.; Temimi, M.; Lakhankar, T.; Khanbilvardi, R.

    2015-12-01

    Soil moisture content is among most important physical parameters in hydrology, climate, and environmental studies. Many microwave-based satellite observations have been utilized to estimate this parameter. The Advanced Microwave Scanning Radiometer 2 (AMSR2) is one of many remotely sensors that collects daily information of land surface soil moisture. However, many factors such as ancillary data and vegetation scattering can affect the signal and the estimation. Therefore, this information needs to be validated against some "ground-truth" observations. NOAA - Cooperative Remote Sensing and Technology (CREST) center at the City University of New York has a site located at Millbrook, NY with several insitu soil moisture probes and an L-Band radiometer similar to Soil Moisture Passive and Active (SMAP) one. This site is among SMAP Cal/Val sites. Soil moisture information was measured at seven different locations from 2012 to 2015. Hydra probes are used to measure six of these locations. This study utilizes the observations from insitu data and the L-Band radiometer close to ground (at 3 meters height) to validate and to compare soil moisture estimates from AMSR2. Analysis of the measurements and AMSR2 indicated a weak correlation with the hydra probes and a moderate correlation with Cosmic-ray Soil Moisture Observing System (COSMOS probes). Several differences including the differences between pixel size and point measurements can cause these discrepancies. Some interpolation techniques are used to expand point measurements from 6 locations to AMSR2 footprint. Finally, the effect of penetration depth in microwave signal and inconsistencies with other ancillary data such as skin temperature is investigated to provide a better understanding in the analysis. The results show that the retrieval algorithm of AMSR2 is appropriate under certain circumstances. This validation algorithm and similar study will be conducted for SMAP mission. Keywords: Remote Sensing, Soil

  17. Network analysis of geomagnetic substorms using the SuperMAG database of ground-based magnetometer stations

    CERN Document Server

    Dods, J; Gjerloev, J W

    2016-01-01

    The overall morphology and dynamics of magnetospheric substorms is well established in terms of the observed qualitative auroral features seen in ground-based magnetometers. This paper focuses on the quantitative characterization of substorm dynamics captured by ground-based magnetometer stations. We present the first analysis of substorms using dynamical networks obtained from the full available set of ground-based magnetometer observations in the Northern Hemisphere. The stations are connected in the network when the correlation between the vector magnetometer time series from pairs of stations within a running time window exceeds a threshold. Dimensionless parameters can then be obtained that characterize the network and by extension, the spatiotemporal dynamics of the substorm under observation. We analyze four isolated substorm test cases as well as a steady magnetic convection (SMC) event and a day in which no substorms occur. These test case substorms are found to give a consistent characteristic netwo...

  18. Determination of the Characteristics of Ground-Based IR Spectral Instrumentation for Environmental Monitoring of the Atmosphere

    Science.gov (United States)

    Makarova, M. V.; Poberovskii, A. V.; Hase, F.; Timofeyev, Yu. M.; Imhasin, Kh. Kh.

    2016-07-01

    This is a study of the spectral characteristics of a ground-based spectral system consisting of an original system for tracking the sun developed at St. Petersburg State University and a Bruker IFS125HR Fourier spectrometer. The importance of accounting for the actual instrument function of the spectral system during processing of ground-based IR spectra of direct solar radiation is illustrated by the example of determining the overall abundance of methane in the atmosphere. Spectral intervals are proposed for taking spectra of direct solar radiation with an HBr cell, which yield information on the parameters of the ground-based system, while simultaneously checking the alignment of the system for each spectrum of the atmosphere.

  19. Evaluation of Anomaly Detection Capability for Ground-Based Pre-Launch Shuttle Operations. Chapter 8

    Science.gov (United States)

    Martin, Rodney Alexander

    2010-01-01

    This chapter will provide a thorough end-to-end description of the process for evaluation of three different data-driven algorithms for anomaly detection to select the best candidate for deployment as part of a suite of IVHM (Integrated Vehicle Health Management) technologies. These algorithms were deemed to be sufficiently mature enough to be considered viable candidates for deployment in support of the maiden launch of Ares I-X, the successor to the Space Shuttle for NASA's Constellation program. Data-driven algorithms are just one of three different types being deployed. The other two types of algorithms being deployed include a "nile-based" expert system, and a "model-based" system. Within these two categories, the deployable candidates have already been selected based upon qualitative factors such as flight heritage. For the rule-based system, SHINE (Spacecraft High-speed Inference Engine) has been selected for deployment, which is a component of BEAM (Beacon-based Exception Analysis for Multimissions), a patented technology developed at NASA's JPL (Jet Propulsion Laboratory) and serves to aid in the management and identification of operational modes. For the "model-based" system, a commercially available package developed by QSI (Qualtech Systems, Inc.), TEAMS (Testability Engineering and Maintenance System) has been selected for deployment to aid in diagnosis. In the context of this particular deployment, distinctions among the use of the terms "data-driven," "rule-based," and "model-based," can be found in. Although there are three different categories of algorithms that have been selected for deployment, our main focus in this chapter will be on the evaluation of three candidates for data-driven anomaly detection. These algorithms will be evaluated upon their capability for robustly detecting incipient faults or failures in the ground-based phase of pre-launch space shuttle operations, rather than based oil heritage as performed in previous studies. Robust

  20. Condition assessment of concrete pavements using both ground penetrating radar and stress-wave based techniques

    Science.gov (United States)

    Li, Mengxing; Anderson, Neil; Sneed, Lesley; Torgashov, Evgeniy

    2016-12-01

    Two stress-wave based techniques, ultrasonic surface wave (USW) and impact echo (IE), as well as ground penetrating radar (GPR) were used to assess the condition of a segment of concrete pavement that includes a layer of concrete, a granular base and their interface. Core specimens retrieved at multiple locations were used to confirm the accuracy and reliability of each non-destructive testing (NDT) result. Results from this study demonstrate that the GPR method is accurate for estimating the pavement thickness and locating separations (air voids) between the concrete and granular base layers. The USW method is a rapid way to estimate the in-situ elastic modulus (dynamic elastic modulus) of the concrete, however, the existence of air voids at the interface could potentially affect the accuracy and reliability of the USW test results. The estimation of the dynamic modulus and the P-wave velocity of concrete was improved when a shorter wavelength range (3 in. to 8.5 in.) corresponding to the concrete layer thickness was applied instead of the full wavelength rage (3 in. to 11 in.) based on the standard spacing of the receiver transducers. The IE method is proved to be fairly accurate in estimating the thickness of concrete pavements. However, the flexural mode vibration could affect the accuracy and reliability of the test results. Furthermore, the existence of air voids between the concrete and granular base layers could affect the estimation of the compression wave velocity of concrete when the full wavelength range was applied (3 in. to 11 in.). Future work is needed in order to improve the accuracy and reliability of both USW and IE test results.

  1. Coastal wind study based on Sentinel-1 and ground-based scanning lidar

    DEFF Research Database (Denmark)

    Hasager, Charlotte Bay; Badger, Merete; Pena Diaz, Alfredo

    Energy (Badger et al. 2016) using GFS winds as input. Wind direction can be checked from the various other observations. Sensitivity to possible deviations in wind directions in the near-shore area will be investigated. Furthermore, oceanic features not related to winds but to e.g. surface current......, breaking waves, etc. will be investigated. The plan is to establish high-quality coastal wind speed cases based on Sentinel-1 for quantification of the coastal winds, for verification of wind resource modelling best practices in the coastal zone. The study is supported by RUNE and New European Wind Atlas...

  2. Validation of five years (2003–2007 of SCIAMACHY CO total column measurements using ground-based spectrometer observations

    Directory of Open Access Journals (Sweden)

    A. M. Poberovskii

    2010-10-01

    Full Text Available This paper presents a validation study of SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY carbon monoxide (CO total column measurements from the Iterative Maximum Likelihood Method (IMLM algorithm using ground-based spectrometer observations from twenty surface stations for the five year time period of 2003–2007. Overall we find a good agreement between SCIAMACHY and ground-based observations for both mean values as well as seasonal variations. For high-latitude Northern Hemisphere stations absolute differences between SCIAMACHY and ground-based measurements are close to or fall within the SCIAMACHY CO 2σ precision of 0.2 × 1018 molecules/cm2 (∼10% indicating that SCIAMACHY can observe CO accurately at high Northern Hemisphere latitudes. For Northern Hemisphere mid-latitude stations the validation is complicated due to the vicinity of emission sources for almost all stations, leading to higher ground-based measurements compared to SCIAMACHY CO within its typical sampling area of 8° × 8°. Comparisons with Northern Hemisphere mountain stations are hampered by elevation effects. After accounting for these effects, the validation provides satisfactory results. At Southern Hemisphere mid- to high latitudes SCIAMACHY is systematically lower than the ground-based measurements for 2003 and 2004, but for 2005 and later years the differences between SCIAMACHY and ground-based measurements fall within the SCIAMACHY precision. The 2003–2004 bias is consistent with previously reported results although its origin remains under investigation. No other systematic spatial or temporal biases could be identified based on the validation presented in this paper. Validation results are robust with regard to the choices of the instrument-noise error filter, sampling area, and time averaging required for the validation of SCIAMACHY CO total column measurements. Finally, our results show that the spatial coverage of the ground-based

  3. The use of products from ground-based GNSS observations in meteorological nowcasting

    Science.gov (United States)

    Terradellas, E.; Callado, A.; Pascual, R.; Téllez, B.

    2009-09-01

    Heavy rainfall is often focalized in areas of moisture convergence. A close relationship between precipitation and fast variations of vertically-integrated water vapour (IWV) has been found in numerous cases. Furthermore, a latency of several tens of minutes of the precipitation relative to a rapid increase of the water vapour contents appears to be a common truth. Therefore, continuous monitoring of atmospheric humidity and its spatial distribution is crucial to the operational forecaster for a proper nowcasting of heavy rainfall events. Radiosonde releases yield measurements of atmospheric humidity, but they are very sparse and present a limited time resolution of 6 to 12 hours. The microwave signals continuously broadcasted by the Global Navigation Satellite System (GNSS) satellites are influenced by the water vapour as they travel through the atmosphere to ground-based receivers. The total zenith delay (ZTD) of these signals, a by-product of the geodetic processing, is already operationally assimilated into numerical weather prediction (NWP) models and has positive impact on the prediction of precipitation events, as it has been reported after the analysis of parallel runs. Estimates of IWV retrieved from ground-based GNSS observations may also constitute a source of information on the horizontal distribution and the time evolution of atmospheric humidity that can be presented to the forecaster. Several advantages can be attributed to the ground-based GNSS as a meteorological observing system. First, receiving networks can be built and maintained at a relatively low cost, which it can, additionally, be shared among different users. Second, the quality of the processed observations is insensitive to the weather conditions and, third, the temporal resolution of its products is very high. On the other hand, the current latency of the data disposal, ranging between one and two hours, is acceptable for the NWP community, but appears to be excessive for nowcasting

  4. Geospace Science from Ground-based Magnetometer Arrays: Advances in Sensors, Data Collection, and Data Integration

    Science.gov (United States)

    Mann, Ian; Chi, Peter

    2016-07-01

    Networks of ground-based magnetometers now provide the basis for the diagnosis of magnetic disturbances associated with solar wind-magnetosphere-ionosphere coupling on a truly global scale. Advances in sensor and digitisation technologies offer increases in sensitivity in fluxgate, induction coil, and new micro-sensor technologies - including the promise of hybrid sensors. Similarly, advances in remote connectivity provide the capacity for truly real-time monitoring of global dynamics at cadences sufficient for monitoring and in many cases resolving system level spatio-temporal ambiguities especially in combination with conjugate satellite measurements. A wide variety of the plasmaphysical processes active in driving geospace dynamics can be monitored based on the response of the electrical current system, including those associated with changes in global convection, magnetospheric substorms and nightside tail flows, as well as due to solar wind changes in both dynamic pressure and in response to rotations of the direction of the IMF. Significantly, any changes to the dynamical system must be communicated by the propagation of long-period Alfven and/or compressional waves. These wave populations hence provide diagnostics for not only the energy transport by the wave fields themselves, but also provide a mechanism for diagnosing the structure of the background plasma medium through which the waves propagate. Ultra-low frequency (ULF) waves are especially significant in offering a monitor for mass density profiles, often invisible to particle detectors because of their very low energy, through the application of a variety of magneto-seismology and cross-phase techniques. Renewed scientific interest in the plasma waves associated with near-Earth substorm dynamics, including magnetosphere-ionosphere coupling at substorm onset and their relation to magnetotail flows, as well the importance of global scale ultra-low frequency waves for the energisation, transport

  5. Mesoscale ionospheric electrodynamics of omega bands determined from ground-based electromagnetic and satellite optical observations

    Directory of Open Access Journals (Sweden)

    O. Amm

    2005-02-01

    Full Text Available We present ground-based electromagnetic data from the MIRACLE and BEAR networks and satellite optical observations from the UVI and PIXIE instruments on the Polar satellite of an omega band event over Northern Scandinavia on 26 June 1998, which occured close to the morning side edge of a substorm auroral bulge. Our analysis of the data concentrates on one omega band period from 03:18-03:27 UT, for which we use the method of characteristics combined with an analysis of the UVI and PIXIE data to derive a time series of instantaneous, solely data-based distributions of the mesoscale ionospheric electrodynamic parameters with a 1-min time resolution. In addition, the AMIE method is used to derive global Hall conductance patterns. Our results show that zonally alternating regions of enhanced ionospheric conductances ("tongues" up to ~60S and low conductance regions are associated with the omega bands. The tongues have a poleward extension of ~400km from their base and a zonal extension of ~380km. While they are moving coherently eastward with a velocity of ~770ms-1, the structures are not strictly stationary. The current system of the omega band can be described as a superposition of two parts: one consists of anticlockwise rotating Hall currents around the tongues, along with Pedersen currents, with a negative divergence in their centers. The sign of this system is reversing in the low conductance areas. It causes the characteristic ground magnetic signature. The second part consists of zonally aligned current wedges of westward flowing Hall currents and is mostly magnetically invisible below the ionosphere. This system dominates the field-aligned current (FAC pattern and causes alternating upward and downward FAC at the flanks of the tongues with maximum upward FAC of ~25µA m-2. The total FAC of ~2MA are comparable to the ones diverted inside a westward traveling surge. Throughout the event, the overwhelming part of the FAC

  6. 3-D or median map? Earthquake scenario ground-motion maps from physics-based models versus maps from ground-motion prediction equations

    Science.gov (United States)

    Porter, K.

    2015-12-01

    There are two common ways to create a ground-motion map for a hypothetical earthquake: using ground motion prediction equations (by far the more common of the two) and using 3-D physics-based modeling. The former is very familiar to engineers, the latter much less so, and the difference can present a problem because engineers tend to trust the familiar and distrust novelty. Maps for essentially the same hypothetical earthquake using the two different methods can look very different, while appearing to present the same information. Using one or the other can lead an engineer or disaster planner to very different estimates of damage and risk. The reasons have to do with depiction of variability, spatial correlation of shaking, the skewed distribution of real-world shaking, and the upward-curving relationship between shaking and damage. The scientists who develop the two kinds of map tend to specialize in one or the other and seem to defend their turf, which can aggravate the problem of clearly communicating with engineers.The USGS Science Application for Risk Reduction's (SAFRR) HayWired scenario has addressed the challenge of explaining to engineers the differences between the two maps, and why, in a disaster planning scenario, one might want to use the less-familiar 3-D map.

  7. HMF sectors since 1926: Comparison of two ground-based data sets

    Science.gov (United States)

    Hiltula, T.; Mursula, K.

    In this paper, we compare two recent long-term data sets of daily HMF sector polarities since 1926 based on ground-based geomagnetic measurements: the combined data set by Echer and Svalgaard [Echer, E., Svalgaard, L. Asymmetry in the Rosenberg-Coleman effect around solar minimum revealed by wavelet analysis of the interplanetary magnetic field polarity data (1927-2002). Geophys. Res. Lett. 31, 12808, 2004] (ES data set) and a three-station data set derived by Vennerstroem et al. [Vennerstroem, S., Zieger, B., Friis-Christensen, E. An improved method of inferring interplanetary sector structure, 1905-present. J. Geophys. Res. 106 (15), 16011-16020, 2001] (VZF data set). The Rosenberg-Coleman rule is consistently valid in the ES data during the last 80 years, but fails in the VZF data set in the early cycles. There is a clear bias (T sector dominance) in the VZF data that is not observed in satellite measurements collected in the OMNI-2 data set, or in the ES data. Also, there is a difference on the success rates between the two sectors in the VZF data. Therefore, we conclude that the ES data set is more reliable, especially in cycles 16-18, in reproducing the HMF sector structure. Both data sets reproduce the southward shift of the heliospheric current sheet during the OMNI-2 interval. However, only the more reliable ES data set depicts this systematically also during the early cycles 16-18.

  8. Secure Web-based Ground System User Interfaces over the Open Internet

    Science.gov (United States)

    Langston, James H.; Murray, Henry L.; Hunt, Gary R.

    1998-01-01

    A prototype has been developed which makes use of commercially available products in conjunction with the Java programming language to provide a secure user interface for command and control over the open Internet. This paper reports successful demonstration of: (1) Security over the Internet, including encryption and certification; (2) Integration of Java applets with a COTS command and control product; (3) Remote spacecraft commanding using the Internet. The Java-based Spacecraft Web Interface to Telemetry and Command Handling (Jswitch) ground system prototype provides these capabilities. This activity demonstrates the use and integration of current technologies to enable a spacecraft engineer or flight operator to monitor and control a spacecraft from a user interface communicating over the open Internet using standard World Wide Web (WWW) protocols and commercial off-the-shelf (COTS) products. The core command and control functions are provided by the COTS Epoch 2000 product. The standard WWW tools and browsers are used in conjunction with the Java programming technology. Security is provided with the current encryption and certification technology. This system prototype is a step in the direction of giving scientist and flight operators Web-based access to instrument, payload, and spacecraft data.

  9. Aircraft wing structural design optimization based on automated finite element modelling and ground structure approach

    Science.gov (United States)

    Yang, Weizhu; Yue, Zhufeng; Li, Lei; Wang, Peiyan

    2016-01-01

    An optimization procedure combining an automated finite element modelling (AFEM) technique with a ground structure approach (GSA) is proposed for structural layout and sizing design of aircraft wings. The AFEM technique, based on CATIA VBA scripting and PCL programming, is used to generate models automatically considering the arrangement of inner systems. GSA is used for local structural topology optimization. The design procedure is applied to a high-aspect-ratio wing. The arrangement of the integral fuel tank, landing gear and control surfaces is considered. For the landing gear region, a non-conventional initial structural layout is adopted. The positions of components, the number of ribs and local topology in the wing box and landing gear region are optimized to obtain a minimum structural weight. Constraints include tank volume, strength, buckling and aeroelastic parameters. The results show that the combined approach leads to a greater weight saving, i.e. 26.5%, compared with three additional optimizations based on individual design approaches.

  10. On Advanced Estimation Techniques for Exoplanet Detection and Characterization using Ground-Based Coronagraphs

    Science.gov (United States)

    Lawson, Peter R.; Frazin, Richard; Barrett, Harrison; Caucci, Luca; Devaney, Nicholas; Furenlid, Lars; Gladysz, Szymon; Guyon, Olivier; Krist, John; Maire, Jerome; Marois, Christian; Mawet, Dimitri; Mouillet, David; Mugnier, Laurent; Perrin, Marshall; Poyneer, Lisa; Pueyo, Laurent; Savransky, Dmitry; Soummer, Remi

    2012-01-01

    The direct imaging of planets around nearby stars is exceedingly difficult. Only about 14 exoplanets have been imaged to date that have masses less than 13 times that of Jupiter. The next generation of planet-finding coronagraphs, including VLT-SPHERE, the Gemini Planet Imager, Palomar P1640, and Subaru HiCIAO have predicted contrast performance of roughly a thousand times less than would be needed to detect Earth-like planets. In this paper we review the state of the art in exoplanet imaging, most notably the method of Locally Optimized Combination of Images (LOCI), and we investigate the potential of improving the detectability of faint exoplanets through the use of advanced statistical methods based on the concepts of the ideal observer and the Hotelling observer. We provide a formal comparison of techniques through a blind data challenge and evaluate performance using the Receiver Operating Characteristic (ROC) and Localization ROC (LROC) curves. We place particular emphasis on the understanding and modeling of realistic sources of measurement noise in ground-based AO-corrected coronagraphs. The work reported in this paper is the result of interactions between the co-authors during a week-long workshop on exoplanet imaging that was held in Squaw Valley, California, in March of 2012.

  11. Characterization of absorbing aerosol types using ground and satellites based observations over an urban environment

    Science.gov (United States)

    Bibi, Samina; Alam, Khan; Chishtie, Farrukh; Bibi, Humera

    2017-02-01

    In this paper, for the first time, an effort has been made to seasonally characterize the absorbing aerosols into different types using ground and satellite based observations. For this purpose, optical properties of aerosol retrieved from AErosol RObotic NETwork (AERONET) and Ozone Monitoring Instrument (OMI) were utilized over Karachi for the period 2012 to 2014. Firstly, OMI AODabs was validated with AERONET AODabs and found to have a high degree of correlation. Then, based on this validation, characterization was conducted by analyzing aerosol Fine Mode Fraction (FMF), Angstrom Exponent (AE), Absorption Angstrom Exponent (AAE), Single Scattering Albedo (SSA) and Aerosol Index (AI) and their mutual correlation, to identify the absorbing aerosol types and also to examine the variability in seasonal distribution. The absorbing aerosols were characterized into Mostly Black Carbon (BC), Mostly Dust and Mixed BC & Dust. The results revealed that Mostly BC aerosols contributed dominantly during winter and postmonsoon whereas, Mostly Dust were dominant during summer and premonsoon. These types of absorbing aerosol were also confirmed with MODerate resolution Imaging Spectroradiometer (MODIS) and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) observations.

  12. Long-term ionospheric anomaly monitoring for ground based augmentation systems

    Science.gov (United States)

    Jung, Sungwook; Lee, Jiyun

    2012-08-01

    Extreme ionospheric anomalies can pose a potential integrity threat to ground-based augmentation of the Global Positioning System (GPS), and thus the development of ionospheric anomaly threat models for each region of operation is essential for system design and operation. This paper presents a methodology for automated long-term ionospheric anomaly monitoring, which will be used to build an ionospheric anomaly threat model, evaluate its validity over the life cycle of the system, continuously monitor ionospheric anomalies, and update the threat model if necessary. This procedure automatically processes GPS data collected from external networks and estimates ionospheric gradients at regular intervals. If ionospheric gradients large enough to be potentially hazardous to users are identified, manual data examination is triggered. This paper also develops a simplified truth processing method to create precise ionospheric delay estimates in near real-time, which is the key to automating the ionospheric monitoring procedure. The performance of the method is examined using data from the 20 November 2003 and 9 November 2004 ionospheric storms. These results demonstrate the effectiveness of simplified truth processing within long-term ionosphere monitoring. From the case studies, the automated procedure successfully identified extreme ionospheric anomalies, including the two worst ionospheric gradients observed and validated previously based on manual analysis. The automation of data processing enables us to analyze ionospheric data continuously going forward and to more accurately categorize ionospheric behavior under both nominal and anomalous conditions.

  13. Estimates for Pu-239 loadings in burial ground culverts based on fast/slow neutron measurements

    Energy Technology Data Exchange (ETDEWEB)

    Winn, W.G.; Hochel, R.C.; Hofstetter, K.J.; Sigg, R.A.

    1989-08-15

    This report provides guideline estimates for Pu-239 mass loadings in selected burial ground culverts. The relatively high recorded Pu-239 contents of these culverts have been appraised as suspect relative to criticality concerns, because they were assayed only with the solid waste monitor (SWM) per gamma-ray counting. After 1985, subsequent waste was also assayed with the neutron coincidence counter (NCC), and a comparison of the assay methods showed that the NCC generally yielded higher assays than the SWM. These higher NCC readings signaled a need to conduct non-destructive/non-intrusive nuclear interrogations of these culverts, and a technical team conducted scoping measurements to illustrate potential assay methods based on neutron and/or gamma counting. A fast/slow neutron method has been developed to estimate the Pu-239 in the culverts. In addition, loading records include the SWM assays of all Pu-239 cuts of some of the culvert drums and these data are useful in estimating the corresponding NCC drum assays from NCC vs SWM data. Together, these methods yield predictions based on direct measurements and statistical inference.

  14. Gap interpolation by inpainting methods : Application to Ground and Space-based Asteroseismic data

    CERN Document Server

    Pires, Sandrine; Garcia, Rafael A; Ballot, Jérôme; Stello, Dennis; Sato, Kumiko

    2014-01-01

    In asteroseismology, the observed time series often suffers from incomplete time coverage due to gaps. The presence of periodic gaps may generate spurious peaks in the power spectrum that limit the analysis of the data. Various methods have been developed to deal with gaps in time series data. However, it is still important to improve these methods to be able to extract all the possible information contained in the data. In this paper, we propose a new approach to handle the problem, the so-called inpainting method. This technique, based on a sparsity prior, enables to judiciously fill-in the gaps in the data, preserving the asteroseismic signal, as far as possible. The impact of the observational window function is reduced and the interpretation of the power spectrum is simplified. This method is applied both on ground and space-based data. It appears that the inpainting technique improves the oscillation modes detection and estimation. Additionally, it can be used to study very long time series of many star...

  15. Heavy precipitation retrieval from combined satellite observations and ground-based lightning measurements

    Science.gov (United States)

    Mugnai, A.; Dietrich, S.; Casella, D.; di Paola, F.; Formenton, M.; Sanò, P.

    2010-09-01

    We have developed a series of algorithms for the retrieval of precipitation (especially, heavy precipitation) over the Mediterranean area using satellite observations from the available microwave (MW) radiometers onboard low Earth orbit (LEO) satellites and from the visible-infrared (VIS-IR) SEVIRI radiometer onboard the European geosynchronous (GEO) satellite Meteosat Second Generation (MSG), in conjunction with lightning data from ground-based networks - such as ZEUS and LINET. These are: • A new approach for precipitation retrieval from space (which we call the Cloud Dynamics and Radiation Database approach, CDRD) that incorporates lightning and environmental/dynamical information in addition to the upwelling microwave brightness temperatures (TB’s) so as to reduce the retrieval uncertainty and improve the retrieval performance; • A new combined MW-IR technique for producing frequent precipitation retrievals from space (which we call PM-GCD technique), that uses passive-microwave (PM) retrievals in conjunction with lightning information and the Global Convection Detection (GCD) technique to discriminate deep convective clouds within the GEO observations; • A new morphing approach (which we call the Lightning-based Precipitation Evolving Technique, L-PET) that uses the available lightning measurements for propagating the rainfall estimates from satellite-borne MW radiometers to a much higher time resolution than the MW observations. We will present and discuss our combined MW/IR/lightning precipitation algorithms and analyses with special reference to some case studies over the western Mediterranean.

  16. A six-beam method to measure turbulence statistics using ground-based wind lidars

    Directory of Open Access Journals (Sweden)

    A. Sathe

    2014-10-01

    Full Text Available A so-called six-beam method is proposed to measure atmospheric turbulence using a ground-based wind lidar. This method requires measurement of the radial velocity variances at five equally spaced azimuth angles on the base of a scanning cone and one measurement at the center of the scanning circle, i.e.using a vertical beam at the same height. The scanning configuration is optimized to minimize the sum of the random errors in the measurement of the second-order moments of the components (u,v, w of the wind field. We present this method as an alternative to the so-called velocity azimuth display (VAD method that is routinely used in commercial wind lidars, and which usually results in significant averaging effects of measured turbulence. In the VAD method, the high frequency radial velocity measurements are used instead of their variances. The measurements are performed using a pulsed lidar (WindScanner, and the derived turbulence statistics (using both methods such as the u and v variances are compared with those obtained from a reference cup anemometer and a wind vane at 89 m height under different atmospheric stabilities. The measurements show that in comparison to the reference cup anemometer, depending on the atmospheric stability and the wind field component, the six-beam method measures between 85–101% of the reference turbulence, whereas the VAD method measures between 66–87% of the reference turbulence.

  17. Reevaluating the feasibility of ground-based Earth-mass microlensing planet detections

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Youn Kil; Park, Hyuk; Han, Cheongho; Hwang, Kyu-Ha; Shin, In-Gu; Choi, Joon-Young, E-mail: cheongho@astroph.chungbuk.ac.kr [Department of Physics, Institute for Astrophysics, Chungbuk National University, Cheongju 371-763 (Korea, Republic of)

    2014-05-10

    An important strength of the microlensing method to detect extrasolar planets is its high sensitivity to low-mass planets. However, many believe that microlensing detections of Earth-mass planets from ground-based observation would be difficult because of limits set by finite-source effects. This view comes from the previous estimation of planet detection probability based on the fractional deviation of planetary signals; however, a proper probability estimation is required when considering the source brightness, which is directly related to the photometric precision. In this paper, we reevaluate the feasibility of low-mass planet detections by considering photometric precision for different populations of source stars. From this, we find that the contribution of improved photometric precision to the planetary signal of a giant-source event is large enough to compensate for the decrease in magnification excess caused by finite-source effects. As a result, we conclude that giant-source events are suitable targets for Earth-mass planet detections with significantly higher detection probability than events involved with source stars of smaller radii, and we predict that Earth-mass planets could be detected by prospective high-cadence surveys.

  18. Ground-based remote sensing scheme for monitoring aerosol–cloud interactions

    Directory of Open Access Journals (Sweden)

    K. Sarna

    2015-11-01

    Full Text Available A method for continuous observation of aerosol–cloud interactions with ground-based remote sensing instruments is presented. The main goal of this method is to enable the monitoring of cloud microphysical changes due to the changing aerosol concentration. We use high resolution measurements from lidar, radar and radiometer which allow to collect and compare data continuously. This method is based on a standardised data format from Cloudnet and can be implemented at any observatory where the Cloudnet data set is available. Two example study cases were chosen from the Atmospheric Radiation Measurement (ARM Program deployment at Graciosa Island, Azores, Portugal in 2009 to present the method. We show the Pearson Product–Moment Correlation Coefficient, r, and the Coefficient of Determination, r2 for data divided into bins of LWP, each of 10 g m−2. We explain why the commonly used way of quantity aerosol cloud interactions by use of an ACI index (ACIr,τ = dln re,τ/dlnα is not the best way of quantifying aerosol–cloud interactions.

  19. A blind deconvolution method for ground based telescopes and Fizeau interferometers

    CERN Document Server

    Prato, M; Bonettini, S; Rebegoldi, S; Bertero, M; Boccacci, P

    2015-01-01

    In the case of ground-based telescopes equipped with adaptive optics systems, the point spread function (PSF) is only poorly known or completely unknown. Moreover, an accurate modeling of the PSF is in general not available. Therefore in several imaging situations the so-called blind deconvolution methods, aiming at estimating both the scientific target and the PSF from the detected image, can be useful. A blind deconvolution problem is severely ill-posed and, in order to reduce the extremely large number of possible solutions, it is necessary to introduce sensible constraints on both the scientific target and the PSF. In a previous paper we proposed a sound mathematical approach based on a suitable inexact alternating minimization strategy for minimizing the generalized Kullback-Leibler divergence, assuring global convergence. In the framework of this method we showed that an important constraint on the PSF is the upper bound which can be derived from the knowledge of its Strehl ratio. The efficacy of the ap...

  20. A six-beam method to measure turbulence statistics using ground-based wind lidars

    Science.gov (United States)

    Sathe, A.; Mann, J.; Vasiljevic, N.; Lea, G.

    2015-02-01

    A so-called six-beam method is proposed to measure atmospheric turbulence using a ground-based wind lidar. This method requires measurement of the radial velocity variances at five equally spaced azimuth angles on the base of a scanning cone and one measurement at the centre of the scanning circle, i.e.using a vertical beam at the same height. The scanning configuration is optimized to minimize the sum of the random errors in the measurement of the second-order moments of the components (u,v, w) of the wind field. We present this method as an alternative to the so-called velocity azimuth display (VAD) method that is routinely used in commercial wind lidars, and which usually results in significant averaging effects of measured turbulence. In the VAD method, the high frequency radial velocity measurements are used instead of their variances. The measurements are performed using a pulsed lidar (WindScanner), and the derived turbulence statistics (using both methods) such as the u and v variances are compared with those obtained from a reference cup anemometer and a wind vane at 89 m height under different atmospheric stabilities. The measurements show that in comparison to the reference cup anemometer, depending on the atmospheric stability and the wind field component, the six-beam method measures between 85 and 101% of the reference turbulence, whereas the VAD method measures between 66 and 87% of the reference turbulence.

  1. Secure Web-based Ground System User Interfaces over the Open Internet

    Science.gov (United States)

    Langston, James H.; Murray, Henry L.; Hunt, Gary R.

    1998-01-01

    A prototype has been developed which makes use of commercially available products in conjunction with the Java programming language to provide a secure user interface for command and control over the open Internet. This paper reports successful demonstration of: (1) Security over the Internet, including encryption and certification; (2) Integration of Java applets with a COTS command and control product; (3) Remote spacecraft commanding using the Internet. The Java-based Spacecraft Web Interface to Telemetry and Command Handling (Jswitch) ground system prototype provides these capabilities. This activity demonstrates the use and integration of current technologies to enable a spacecraft engineer or flight operator to monitor and control a spacecraft from a user interface communicating over the open Internet using standard World Wide Web (WWW) protocols and commercial off-the-shelf (COTS) products. The core command and control functions are provided by the COTS Epoch 2000 product. The standard WWW tools and browsers are used in conjunction with the Java programming technology. Security is provided with the current encryption and certification technology. This system prototype is a step in the direction of giving scientist and flight operators Web-based access to instrument, payload, and spacecraft data.

  2. Airborne and Ground-Based Optical Characterization of Legacy Underground Nuclear Test Sites

    Science.gov (United States)

    Vigil, S.; Craven, J.; Anderson, D.; Dzur, R.; Schultz-Fellenz, E. S.; Sussman, A. J.

    2015-12-01

    Detecting, locating, and characterizing suspected underground nuclear test sites is a U.S. security priority. Currently, global underground nuclear explosion monitoring relies on seismic and infrasound sensor networks to provide rapid initial detection of potential underground nuclear tests. While seismic and infrasound might be able to generally locate potential underground nuclear tests, additional sensing methods might be required to further pinpoint test site locations. Optical remote sensing is a robust approach for site location and characterization due to the ability it provides to search large areas relatively quickly, resolve surface features in fine detail, and perform these tasks non-intrusively. Optical remote sensing provides both cultural and surface geological information about a site, for example, operational infrastructure, surface fractures. Surface geological information, when combined with known or estimated subsurface geologic information, could provide clues concerning test parameters. We have characterized two legacy nuclear test sites on the Nevada National Security Site (NNSS), U20ak and U20az using helicopter-, ground- and unmanned aerial system-based RGB imagery and light detection and ranging (lidar) systems. The multi-faceted information garnered from these different sensing modalities has allowed us to build a knowledge base of how a nuclear test site might look when sensed remotely, and the standoff distances required to resolve important site characteristics.

  3. [Cr(III)8M(II)6](12+) Coordination Cubes (M(II)=Cu, Co).

    Science.gov (United States)

    Sanz, Sergio; O'Connor, Helen M; Pineda, Eufemio Moreno; Pedersen, Kasper S; Nichol, Gary S; Mønsted, Ole; Weihe, Høgni; Piligkos, Stergios; McInnes, Eric J L; Lusby, Paul J; Brechin, Euan K

    2015-06-01

    [Cr(III)8M(II)6](12+) (M(II) =Cu, Co) coordination cubes were constructed from a simple [Cr(III) L3 ] metalloligand and a "naked" M(II) salt. The flexibility in the design proffers the potential to tune the physical properties, as all the constituent parts of the cage can be changed without structural alteration. Computational techniques (known in theoretical nuclear physics as statistical spectroscopy) in tandem with EPR spectroscopy are used to interpret the magnetic behavior.

  4. MAD-4-MITO, a Multi Array of Detectors for ground-based mm/submm SZ observations

    CERN Document Server

    Lamagna, L; Melchiorri, F; Battistelli, E S; De Grazia, M; Luzzi, G; Orlando, A E; Savini, G

    2002-01-01

    The last few years have seen a large development of mm technology and ultra-sensitive detectors devoted to microwave astronomy and astrophysics. The possibility to deal with large numbers of these detectors assembled into multi--pixel imaging systems has greatly improved the performance of microwave observations, even from ground--based stations, especially combining the power of multi--band detectors with their new imaging capabilities. Hereafter, we will present the development of a multi--pixel solution devoted to Sunyaev--Zel'dovich observations from ground--based telescopes, that is going to be operated from the Millimetre and Infrared Testagrigia Observatory.

  5. Analysis of global climate variability from homogenously reprocessed ground-based GNSS measurements

    Science.gov (United States)

    Ahmed, Furqan; Hunegnaw, Addisu; Teferle, Felix Norman; Bingley, Richard

    2015-04-01

    The tropospheric delay information obtained through long-term homogenous reprocessing of Global Navigation Satellite System (GNSS) observations can be used for climate change and variability analysis on a global scale. A reprocessed global dataset of GNSS-derived zenith total delay (ZTD) and position estimates, based on the network double differencing (DD) strategy and covering 1994-2012, has been recently produced at the University of Luxembourg using the Bernese GNSS Software 5.2 (BSW5.2) and the reprocessed products from the Centre for Orbit Determination in Europe (CODE). The network of ground-based GNSS stations processed to obtain this dataset consists of over 400 globally distributed stations. The GNSS-derived ZTD has been validated by comparing it to that derived from reanalysis data from the European Centre for Medium-Range Weather Forecasts (ECMWF). After validation and quality control, the ZTD dataset obtained using the DD strategy has been used to investigate the inter-annual, seasonal and diurnal climate variability and trends in the tropospheric delay on various regional to global spatial scales. Precise point positioning (PPP) is a processing strategy for GNSS observations which is based on observations from a single station rather than a network of baselines and is therefore computationally more efficient than the DD strategy. However, the two processing strategies, i.e. DD and PPP, have their own strengths and weaknesses and could affect the solutions differently at different geographical locations. In order to explore the use of PPP strategy for climate monitoring, another experimental dataset covering a shorter period has been produced using the PPP strategy and compared to the DD based ZTD dataset.

  6. Configurable adaptive optical system for imaging of ground-based targets from space

    Science.gov (United States)

    McComas, Brian K.; Friedman, Edward J.; Hooker, R. Brian; Cermak, Michael A.

    2003-03-01

    Space-based, high resolution, Earth remote sensing systems, that employ large, flexible, lightweight primary mirrors, will require active wavefront correction, in the form of active and adaptive optics, to correct for thermally and vibrationally induced deformations in the optics. These remote sensing systems typically have a large field-of-view. Unlike the adaptive optics on ground-based astronomical telescopes, which have a negligible field-of-view, the adaptive optics on these space-based remote sensing systems will be required to correct the wavefront over the entire field-of-view, which can be several degrees. The error functions for astronomical adaptive optics have been developed for the narrow field-of-view correction of atmospheric turbulence and do not address the needs of wide field space-based systems. To address these needs, a new wide field adaptive optics theory and a new error function are developed. Modeling and experimental results demonstrate the validity of the wide field adaptive optics theory and new error function. This new error function, which is a new extension of conventional adaptive optics, lead to the development of three new types of imaging systems: wide field-of-view, selectable field-of-view, and steerable field-of-view. These new systems can have nearly diffraction-limited performance across the entire field-of-view or a narrow movable region of high-resolution imaging. The factors limiting system performance will be shown. The range of applicability of the wide field adaptive optics theory is shown. The range of applicability is used to avoid limitations in system performance and to estimate the optical systems parameters, which will meet the system"s performance requirements.

  7. The relation between solar and seismic activity based on satellite and ground-based data

    Science.gov (United States)

    Kirov, B.; Georgieva, K.; Atanasov, D.; Haiakawa, M.

    It has been noted that a significant correlation exists between solar and seismic activity on different time-scales, from centennial (Gleissberg) to the 11-year solar cycle, however the solar activity agent and the mechanism for this influence remained unclear. As two well expressed maxima of the number of earthquakes are observed in the 11-year solar cycle, one coinciding with sunspot maximum, and the other with solar coronal holes maximum, it has been supposed that the agent triggering seismic activity could be the high-speed solar wind. Data from numerous spacecraft monitoring solar wind parameters have been used compiled in OMNI data-base, and it has been found that the number of earthquakes in the days of the arrival of high speed solar wind and the days following right after them is significantly greater than in all other days. Further, we use data for the Earth rotation rate from the International Earth Rotation Service, and for the atmospheric circulation from meteorological stations worldwide. We find that they are both related to seismic activity, and discuss a possible mechanism of solar activity influences on the number of earthquakes through solar wind influences on the Earth and atmospheric dynamics.

  8. A method for cloud detection and opacity classification based on ground based sky imagery

    Directory of Open Access Journals (Sweden)

    M. S. Ghonima

    2012-07-01

    Full Text Available Digital images of the sky obtained using a total sky imager (TSI are classified pixel by pixel into clear sky, optically thin and optically thick clouds. A new classification algorithm was developed that compares the pixel red-blue ratio (RBR to the RBR of a clear sky library (CSL generated from images captured on clear days. The difference, rather than the ratio, between pixel RBR and CSL RBR resulted in more accurate cloud classification. High correlation between TSI image RBR and aerosol optical depth (AOD measured by an AERONET photometer was observed and motivated the addition of a haze correction factor (HCF to the classification model to account for variations in AOD. Thresholds for clear and thick clouds were chosen based on a training image set and validated with set of manually annotated images. Misclassifications of clear and thick clouds into the opposite category were less than 1%. Thin clouds were classified with an accuracy of 60%. Accurate cloud detection and opacity classification techniques will improve the accuracy of short-term solar power forecasting.

  9. A method for cloud detection and opacity classification based on ground based sky imagery

    Directory of Open Access Journals (Sweden)

    M. S. Ghonima

    2012-11-01

    Full Text Available Digital images of the sky obtained using a total sky imager (TSI are classified pixel by pixel into clear sky, optically thin and optically thick clouds. A new classification algorithm was developed that compares the pixel red-blue ratio (RBR to the RBR of a clear sky library (CSL generated from images captured on clear days. The difference, rather than the ratio, between pixel RBR and CSL RBR resulted in more accurate cloud classification. High correlation between TSI image RBR and aerosol optical depth (AOD measured by an AERONET photometer was observed and motivated the addition of a haze correction factor (HCF to the classification model to account for variations in AOD. Thresholds for clear and thick clouds were chosen based on a training image set and validated with set of manually annotated images. Misclassifications of clear and thick clouds into the opposite category were less than 1%. Thin clouds were classified with an accuracy of 60%. Accurate cloud detection and opacity classification techniques will improve the accuracy of short-term solar power forecasting.

  10. TOMS and Ground-based Measurements: Long-term Trends, Spatial Variability, Cloud Effects, and Data Quality.

    Science.gov (United States)

    Eide, H. A.; Dahlback, A.; Stamnes, K.; Høyskar, B.; Olsen, R.; Schmidlin, F.; Tsay, S.

    2003-12-01

    Ground-based measurements and TOMS measurements are mutually beneficial to each other. Ground-based measurements of UV radiation and total column ozone amounts are important for the validation of TOMS measurements. For example, it has been shown that TOMS measurements has a tendency to under-estimate ground UV exposure. Some of these effects can perhaps be ascribed to local cloud effects or choice of ozone profiles in the retrieval algorithm. More ground-based measurements are needed to establish the cause of these discrepancies. Recent technology advances have made ground-based measurements of UV doses and ozone column amounts with inexpensive multi-channel filter instruments not only possible, but also an attractive alternative to other more labor-intensive and weather dependent methods. Filter instruments can operate unattended for long periods of time, and it is possible to obtain accurate ozone column amounts even on cloudy days. We present results from extensive comparisons of the performance of several ground-based instruments (the NILU-UV and GUV filter instruments, as well as the Dobson and Brewer instruments) against the EP-TOMS instrument. The data used in the comparisons are from three different sites where we have had the opportunity to operate more than one type of UV instruments for extended periods of time. The sites include the University of Oslo, Norway, the NASA Goddard Space Flight Center facilities at Wallops Island, VA, and Greenbelt, MD and the University of Alaska, Fairbanks (during the TOMS3F campaign). Our results show that ozone column amounts obtained with current filter-type instruments are just as good as those obtained with the Dobson instrument, and might even out-perform the Dobson instrument on cloudy days. The TOMS measurements are shown to exhibit some more variability, but there is on average very good agreement with the ground- based measurements even for high solar zenith angles (SZA). Further more, our comparison shows that

  11. The thermo-vibrational convection in microgravity condition. Ground-based modelling.

    Science.gov (United States)

    Zyuzgin, A. V.; Putin, G. F.; Harisov, A. F.

    In 1995-2000 at orbital station "Mir" has been carried out the series of experiments with the equipment "Alice" for the studying regimes of heat transfer in the supercritical fluids under influence inertial microaccelerations. The experiments have found out existence of the thermo-vibrational and thermo-inertial convective movements in the real weightlessness[1] and controlling microgravity fields[2]. However regarding structures of thermovibrational convection the results of experiments have inconsistent character. Therefore carrying out the ground-based modeling of the given problem is actually. In this work in laboratory conditions were investigated the thermo-vibrational convective movements from the dot heat source at high-frequency vibrations of the cavity with the fluid and presence quasi-static microacceleration. As the result of ground-based modeling, the regimes of convective flows, similar observed in the space experiment are received. Evolution of the convective structures and the spatial-temporary characteristics of movements are investigated in a wide range of the problem parameters. The control criteria and its critical value are determined. The received results well coordinated to the data of space experiments and allow adding and expanding representation about thermo-vibrational effects in conditions of real weightlessness and remove the contradictions concerning structures thermo-vibrational convective flows, received at the analysis of the given orbital experiments. The research described in this publication was made possible in part by Russian Foundation for Basic Research and Administration of Perm Region, Russia, under grant 04-02-96038, and Award No. PE-009-0 of the U.S. Civilian Research & Development Foundation for the Independent States of the Former Soviet Union (CRDF). A.V. Zyuzgin, A. I. Ivanov, V. I. Polezhaev, G. F. Putin, E. B. Soboleva Convective Motions in Near-Critical Fluids under Real Zero-Gravity Conditions. Cosmic Research

  12. Historical Trends in Ground-Based Optical Space Surveillance System Design

    Science.gov (United States)

    Shoemaker, M.; Shroyer, L.

    In the spirit of the 50th anniversary of the launch of the first man-made satellite, an historical overview of ground-based optical space surveillance systems is provided. Specific emphasis is given on gathering metrics to analyze design trends. The subject of space surveillance spans the history of spaceflight: from the early tracking cameras at missile ranges, the first observations of Sputnik, to the evolution towards highly capable commercial off-the-shelf (COTS) systems, and much in between. Whereas previous reviews in the literature have been limited in scope to specific time periods, operational programs, countries, etc., a broad overview of a wide range of sources is presented. This review is focused on systems whose primary design purpose can be classified as Space Object Identification (SOI) or Orbit Determination (OD). SOI systems are those that capture images or data to determine information about the satellite itself, such as attitude, features, and material composition. OD systems are those that produce estimates of the satellite position, usually in the form of orbital elements or a time history of tracking angles. Systems are also categorized based on the orbital regime in which their targets reside, which has been simplified in this study to either Low Earth Orbit (LEO) or Geosynchronous Earth Orbit (GEO). The systems are further classified depending on the industry segment (government/commercial or academic), and whether the program is foreign or domestic. In addition to gathering metrics on systems designed solely for man-made satellite observations, it is interesting to find examples of other systems being similarly used. Examples include large astronomical telescopes being used for GEO debris surveys and anomaly resolution for deep-space probes. Another interesting development is the increase in number and capability of COTS systems, some of which are specifically marketed to consumers as satellite trackers. After describing the results of the

  13. Unattended instruments for ground-based hyperspectral measurements: development and application for plant photosynthesis monitoring

    Science.gov (United States)

    Cogliati, S.; Rossini, M.; Meroni, M.; Barducci, A.; Julitta, T.; Colombo, R.

    2011-12-01

    The aim of the present work is the development of ground-based hyperspectral systems capable of collecting continuous and long-term hyperspectral measurements of the Earth-surface. The development of such instruments includes the optical design, the development of the data acquisition (Auto3S) and processing software as well as the definition of the calibration procedures. In particular an in-field calibration methodologie based on the comparison between field spectra and data modeled using Radiative Transfer (RT) approach has been proposed to regularly upgrade instrument calibration coefficients. Two different automatic spectrometric systems have been developed: the HyperSpectral Irradiometer (HSI) [Meroni et al., 2011] and the Multiplexer Radiometer Irradiometer (MRI) [Cogliati, 2011]. Both instruments are able to continuously measure: sun incoming irradiance (ETOT) and irradiance (ES, HSI)/radiance (LS, MRI) upwelling from the investigated surface. Both instruments employ two Ocean Optics HR4000 spectrometers sharing the same optical signal that allow to simultaneously collect "fine" (1 nm Full Width at Half Maximum, FWHM) spectra in the 400-1000 nm rangeand "ultra-fine" (0.1 nm FWHM) spectra within the 700-800 nm. The collected optical data allow to estimate biochemical/structural properties of vegetation (e.g. NDVI) as well as its photosynthetic efficiency through the Photochemical Reflectance Index (PRI) and the analysis of sun-induced chlorophyll Fluorescence in the O2-A Fraunhofer line (F@760). The automatic instruments were operated in coordination with eddy covariance flux tower measurements of carbon exchange in the framework of several field campaigns: HSI was employed in a subalpine pasture (2009-ongoing) (www.phenoalp.eu) while MRI was employed in 2009 in the Sen3Exp field survey promoted by the European Space Agency as consolidation study to the future mission Sentinel-3. Results show that the proposed instruments succeeded in collecting continuous

  14. Suitability of ground-based SfM-MVS for monitoring glacial and periglacial processes

    Science.gov (United States)

    Piermattei, Livia; Carturan, Luca; de Blasi, Fabrizio; Tarolli, Paolo; Dalla Fontana, Giancarlo; Vettore, Antonio; Pfeifer, Norbert

    2016-05-01

    Photo-based surface reconstruction is rapidly emerging as an alternative survey technique to lidar (light detection and ranging) in many fields of geoscience fostered by the recent development of computer vision algorithms such as structure from motion (SfM) and dense image matching such as multi-view stereo (MVS). The objectives of this work are to test the suitability of the ground-based SfM-MVS approach for calculating the geodetic mass balance of a 2.1 km2 glacier and for detecting the surface displacement of a neighbouring active rock glacier located in the eastern Italian Alps. The photos were acquired in 2013 and 2014 using a digital consumer-grade camera during single-day field surveys. Airborne laser scanning (ALS, otherwise known as airborne lidar) data were used as benchmarks to estimate the accuracy of the photogrammetric digital elevation models (DEMs) and the reliability of the method. The SfM-MVS approach enabled the reconstruction of high-quality DEMs, which provided estimates of glacial and periglacial processes similar to those achievable using ALS. In stable bedrock areas outside the glacier, the mean and the standard deviation of the elevation difference between the SfM-MVS DEM and the ALS DEM was -0.42 ± 1.72 and 0.03 ± 0.74 m in 2013 and 2014, respectively. The overall pattern of elevation loss and gain on the glacier were similar with both methods, ranging between -5.53 and + 3.48 m. In the rock glacier area, the elevation difference between the SfM-MVS DEM and the ALS DEM was 0.02 ± 0.17 m. The SfM-MVS was able to reproduce the patterns and the magnitudes of displacement of the rock glacier observed by the ALS, ranging between 0.00 and 0.48 m per year. The use of natural targets as ground control points, the occurrence of shadowed and low-contrast areas, and in particular the suboptimal camera network geometry imposed by the morphology of the study area were the main factors affecting the accuracy of photogrammetric DEMs negatively

  15. Evaluation of atmospheric dust prediction models using ground-based observations

    Science.gov (United States)

    Terradellas, Enric; María Baldasano, José; Cuevas, Emilio; Basart, Sara; Huneeus, Nicolás; Camino, Carlos; Dundar, Cinhan; Benincasa, Francesco

    2013-04-01

    An important step in numerical prediction of mineral dust is the model evaluation aimed to assess its performance to forecast the atmospheric dust content and to lead to new directions in model development and improvement. The first problem to address the evaluation is the scarcity of ground-based routine observations intended for dust monitoring. An alternative option would be the use of satellite products. They have the advantage of a large spatial coverage and a regular availability. However, they do have numerous drawbacks that make the quantitative retrievals of aerosol-related variables difficult and imprecise. This work presents the use of different ground-based observing systems for the evaluation of dust models in the Regional Center for Northern Africa, Middle East and Europe of the World Meteorological Organization (WMO) Sand and Dust Storm Warning Advisory and Assessment System (SDS-WAS). The dust optical depth at 550 nm forecast by different models is regularly compared with the AERONET measurements of Aerosol Optical Depth (AOD) for 40 selected stations. Photometric measurements are a powerful tool for remote sensing of the atmosphere allowing retrieval of aerosol properties, such as AOD. This variable integrates the contribution of different aerosol types, but may be complemented with spectral information that enables hypotheses about the nature of the particles. Comparison is restricted to cases with low Ångström exponent values in order to ensure that coarse mineral dust is the dominant aerosol type. Additionally to column dust load, it is important to evaluate dust surface concentration and dust vertical profiles. Air quality monitoring stations are the main source of data for the evaluation of surface concentration. However they are concentrated in populated and industrialized areas around the Mediterranean. In the present contribution, results of different models are compared with observations of PM10 from the Turkish air quality network for

  16. Comparison of GOME tropospheric NO2 columns with NO2 profiles deduced from ground-based in situ measurements

    Directory of Open Access Journals (Sweden)

    D. Schaub

    2006-01-01

    Full Text Available Nitrogen dioxide (NO2 vertical tropospheric column densities (VTCs retrieved from the Global Ozone Monitoring Experiment (GOME are compared to coincident ground-based tropospheric NO2 columns. The ground-based columns are deduced from in situ measurements at different altitudes in the Alps for 1997 to June 2003, yielding a unique long-term comparison of GOME NO2 VTC data retrieved by a collaboration of KNMI (Royal Netherlands Meteorological Institute and BIRA/IASB (Belgian Institute for Space Aeronomy with independently derived tropospheric NO2 profiles. A first comparison relates the GOME retrieved tropospheric columns to the tropospheric columns obtained by integrating the ground-based NO2 measurements. For a second comparison, the tropospheric profiles constructed from the ground-based measurements are first multiplied with the averaging kernel (AK of the GOME retrieval. The second approach makes the comparison independent from the a priori NO2 profile used in the GOME retrieval. This allows splitting the total difference between the column data sets into two contributions: one that is due to differences between the a priori and the ground-based NO2 profile shapes, and another that can be attributed to uncertainties in both the remaining retrieval parameters (such as, e.g., surface albedo or aerosol concentration and the ground-based in situ NO2 profiles. For anticyclonic clear sky conditions the comparison indicates a good agreement between the columns (n=157, R=0.70/0.74 for the first/second comparison approach, respectively. The mean relative difference (with respect to the ground-based columns is −7% with a standard deviation of 40% and GOME on average slightly underestimating the ground-based columns. Both data sets show a similar seasonal behaviour with a distinct maximum of spring NO2 VTCs. Further analysis indicates small GOME columns being systematically smaller than the ground-based ones. The influence of different shapes in the a

  17. Designing of a risk assessment architecture to analyze potential risks from space weather to space and ground based assets

    Science.gov (United States)

    Sattar, Erum

    2016-07-01

    Today's world is more vulnerable to space weather due to ever increased advance and costly space technology deployed in space and on ground. The space weather has a natural potential of posing harmful effects on space and ground based assets and on astronaut's life. This global challenge of space weather essentially demands global and regional preparedness to develop its situational awareness, analyzing risks and devise possible mitigation procedures. Considering risk mitigation architecture as inevitable for all scientific missions, this paper focuses to develop a risk assessment architecture for the space environment and to map its utility in identifying and analyzing potential risks to space and ground based assets from space weather in the South Asia region. Different risk assessment tools will be studied and would conclude in the most effective tool or strategy that may help to develop our capability in identifying, protecting and mitigating from the devastating effects of the space weather.

  18. The effects of thermal aging on material behavior and strength of CF8M in nuclear reactor coolant system

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Jae Do; Lee, Yong Seon; Park, Jung Cheol; In, Jae Hyeon; Woo, Seung Wan; Pae, Yong Tak; Nam, Uk Hui; Park, Yun Won [Yeungnam Univ., Gyeongsan (Korea, Republic of)

    1999-03-15

    The following investigations are performed in order to estimate the mechanism of the structural integrity, and the life prediction. The CF8M is observed a brittle behavior in the range of 475 .deg. C. The five classes of the thermally aged CF8M specimen are prepared using an artificially accelerated aging method. Namely, after the specimen are held for 100, 300, 900, 1800 and 3600 hrs. at 430 .deg. C respectively, the specimen are water cooled to room temperature. In addition to the thermally aged specimens the specimens associated with {delta}-phase degradation are prepared. After the specimens are maintained for 20 min, 5, 15, 50 and 150 hrs. at 700 .deg. C, respectively. which is in the range of {delta}-phase degradation, all specimens are cooled in water. The impact energy variations are measured for both the aged and virgin specimen at -173, -70, -32, 27 and 100 .deg. C, respectively, through the Charpy impact tests in addition to the hardness tests. The characteristics of the fatigue crack growth and low cycle fatigue tests are investigated using both aged and virgin specimens. Also fractured surfaces of the specimen are observed using the scanning electronic microscopy. J-R curve and J{sub IC} of the aged and virgin specimens are found J{sub IC} in order to predict the critical flaw size and fatigue life.

  19. The effects of thermal aging on material behavior and strength of CF8M in nuclear reactor coolant system

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Jae Do; Lee, Yong Seon; Park, Jung Cheol; In, Jae Hyeon; Woo, Seung Wan; Pae, Yong Tak; Nam, Uk Hui; Park, Yun Won [Yeungnam Univ., Gyeongsan (Korea, Republic of)

    1999-03-15

    The following investigations are performed in order to estimate the mechanism of the structural integrity, and the life prediction. The CF8M is observed a brittle behavior in the range of 475 .deg. C. The five classes of the thermally aged CF8M specimen are prepared using an artificially accelerated aging method. Namely, after the specimen are held for 100, 300, 900, 1800 and 3600 hrs. at 430 .deg. C respectively, the specimen are water cooled to room temperature. In addition to the thermally aged specimens the specimens associated with {delta}-phase degradation are prepared. After the specimens are maintained for 20 min, 5, 15, 50 and 150 hrs. at 700 .deg. C, respectively. which is in the range of {delta}-phase degradation, all specimens are cooled in water. The impact energy variations are measured for both the aged and virgin specimen at -173, -70, -32, 27 and 100 .deg. C, respectively, through the Charpy impact tests in addition to the hardness tests. The characteristics of the fatigue crack growth and low cycle fatigue tests are investigated using both aged and virgin specimens. Also fractured surfaces of the specimen are observed using the scanning electronic microscopy. J-R curve and J{sub IC} of the aged and virgin specimens are found J{sub IC} in order to predict the critical flaw size and fatigue life.

  20. Soil moisture on Polish territory - comparison of satellite and ground-based measurements

    Science.gov (United States)

    Rojek, Edyta; Łukowski, Mateusz; Marczewski, Wojciech; Usowicz, Bogusław

    2014-05-01

    Assessment of water resources due to changing climatic conditions in time and space is still very uncertain. The territory of Poland has a limited resource of waters, occasionally resulting in small agricultural droughts. From the other side intense rainfalls, floods or run-offs, causing soil erosion are observed. Therefore, it is important to predict and prevent of this adverse phenomena. Huge spatial variability of soil moisture does not allow for accurate estimation of its distribution using ground-based measurements. SMOS soil moisture data are quite much inherently consistent in time and space, but their validation is still a challenge for further use in the climate and hydrology studies. This is the motivation for the research: to examine soil moisture from SMOS and ground based stations of the SWEX network held over eastern Poland. The presented results are related to changes of the soil moisture on regional scales for Poland in the period 2010-2013. Some results with SMOS L2 data are extended on continental scales for Europe. Time series from ground and satellite SMOS data sources were compared by regression methods. The region of Poland indicates clearly some genetic spatial distributions in weekly averaged values. In continental scales, the country territory contrasts evidently to Lithuania and in Polesie, and indicates seasonal cycling observed in archives and well known traditional records. The central part of Poland is repeatedly susceptible on droughts with soil moisture values ranging from about 0.02 to 0.20 m3 m-3. SMOS data allows on creating systematic drought data for Poland and watching annual changes, and differences to other drought services kept on national scales for agricultural purposes. We bound that drought susceptibility to the content of sand clay components and the land use there. Lack of rainfall in the late 2011 summer, caused a significant deficit of water in soil moisture content (below 0.05 m3 m-3) throughout the entire country