Science.gov

Sample records for nadir angle results

  1. Extension of the GPS satellite antenna patterns to nadir angles beyond 14°

    NASA Astrophysics Data System (ADS)

    Jaeggi, A.; Dilssner, F.; Schmid, R.; Dach, R.; Springer, T.; Bock, H.; Steigenberger, P.; Andres, Y.; Enderle, W.

    2012-04-01

    The absolute phase center model igs08.atx adopted by the International GNSS Service (IGS) in 2011 is based on robot calibrations for more than 200 terrestrial GNSS receiver antennas and consistent correction values for the GNSS transmitter antennas estimated from tracking data of the global IGS ground network. As the calibration of the satellite antennas is solely based on terrestrial measurements, the estimation of their phase patterns is limited to a nadir angle of 14°. This is not sufficient for the analysis of spaceborne GPS data collected by low Earth orbiting (LEO) satellites that record - depending on the missions' orbital altitude - observations at nadir angles of up to 17°. We use GPS tracking data from the LEO missions Jason-1/2, MetOp-A, GRACE, and GOCE to extend the IGS satellite antenna patterns to nadir angles beyond 14° using different processing strategies and GNSS software packages (BERNESE, NAPEOS). In order to achieve estimates that are consistent with the PCVs currently used within the IGS, GPS satellite orbits and clocks are fixed to reprocessed solutions obtained by adopting the IGS conventional values from igs08.atx. Due to significant near-field multipath effects arising in the LEO spacecraft environment, it is necessary to solve for GPS (nadir-dependent only) and LEO (azimuth- and elevation-dependent) antenna patterns simultaneously. We compare and combine the results obtained with both software packages and derive the PCV extension proposed for igs08.atx.

  2. Change detection from very high resolution satellite time series with variable off-nadir angle

    NASA Astrophysics Data System (ADS)

    Barazzetti, Luigi; Brumana, Raffaella; Cuca, Branka; Previtali, Mattia

    2015-06-01

    Very high resolution (VHR) satellite images have the potential for revealing changes occurred overtime with a superior level of detail. However, their use for metric purposes requires accurate geo-localization with ancillary DEMs and GCPs to achieve sub-pixel terrain correction, in order to obtain images useful for mapping applications. Change detection with a time series of VHS images is not a simple task because images acquired with different off-nadir angles have a lack of pixel-to-pixel image correspondence, even after accurate geo-correction. This paper presents a procedure for automatic change detection able to deal with variable off-nadir angles. The case study concerns the identification of damaged buildings from pre- and post-event images acquired on the historic center of L'Aquila (Italy), which was struck by an earthquake in April 2009. The developed procedure is a multi-step approach where (i) classes are assigned to both images via object-based classification, (ii) an initial alignment is provided with an automated tile-based rubber sheeting interpolation on the extracted layers, and (iii) change detection is carried out removing residual mis-registration issues resulting in elongated features close to building edges. The method is fully automated except for some thresholds that can be interactively set to improve the visualization of the damaged buildings. The experimental results proved that damages can be automatically found without additional information, such as digital surface models, SAR data, or thematic vector layers.

  3. Extending the GPS satellite antenna patterns of the IGS to nadir angles beyond 14° using LEO data

    NASA Astrophysics Data System (ADS)

    Dach, R.; Jaeggi, A.; Bock, H.; Beutler, G.; Montenbruck, O.; Schmid, R.

    2010-12-01

    The absolute phase center model adopted by the International GNSS Service (IGS) in 2006 is based on robot calibrations for a number of terrestrial GNSS receiver antennas and consistent correction values for the GNSS transmitter antennas estimated from data of the global IGS tracking network. As the calibration of the satellite antennas is solely based on terrestrial measurements, the estimation of their phase patterns is limited to a nadir angle of 14°. This is not sufficient for the analysis of spaceborne GPS data collected by low Earth orbiting (LEO) satellites that record observations at nadir angles of up to 17°. Moreover, phase center variation (PCV) estimates for nadir angles close to 14° derived from terrestrial measurements might be affected by uncertainties in the troposphere modeling. This drawback could also be overcome by the use of LEO data. We use GPS tracking data from several LEO missions to extend the IGS satellite antenna patterns to nadir angles beyond 14°. In order to achieve estimates that are consistent with the PCVs currently used within the IGS, GPS and LEO orbits are fixed to solutions obtained by adopting the IGS conventional values. Due to significant near-field multipath effects in the LEO spacecraft environment, it is necessary to solve for GPS (nadir-dependent only) and LEO (azimuth- and elevation-dependent) antenna patterns simultaneously. We analyze the separability of these parameters and discuss appropriate constraints. We assess the contribution of different LEO missions to a combined solution and analyze the impact of LEO orbit modeling errors.

  4. Sensitivity of MODIS 2.1-(micrometers) Channel for Off-Nadir View Angles for Use in Remote Sensing of Aerosol

    NASA Technical Reports Server (NTRS)

    Gatebe, C. K.; King, M. D.; Tsay, S.-C.; Ji, Q.; Arnold, T.

    2000-01-01

    In this sensitivity study, we examined the ratio technique, the official method for remote sensing of aerosols over land from Moderate Resolution Imaging Spectroradiometer (MODIS) DATA, for view angles from nadir to 65 deg. off-nadir using Cloud Absorption Radiometer (CAR) data collected during the Smoke, Clouds, and Radiation-Brazil (SCAR-B) experiment conducted in 1995. For the data analyzed and for the view angles tested, results seem to suggest that the reflectance (rho)0.47 and (rho)0.67 are predictable from (rho)2.1 using: (rho)0.47 = (rho)2.1/6, which is a slight modification and (rho)0.67 = (rho)2.1/2. These results hold for target viewed from backscattered direction, but not for the forward direction.

  5. Sensitivity of MODIS 2.1 micron Channel for Off-Nadir View Angles for Use in Remote Sensing of Aerosol

    NASA Technical Reports Server (NTRS)

    Gatebe, C. K.; King, M. D.; Tsay, S.-C.; Ji, Q.

    2000-01-01

    Remote sensing of aerosol over land, from MODIS will be based on dark targets using mid-IR channels 2.1 and 3.9 micron. This approach was developed by Kaufman et al (1997), who suggested that dark surface reflectance in the red (0.66 micron -- rho(sub 0.66)) channel is half of that at 2.2 micron (rho(sub 2.2)), and the reflectance in the blue (0.49 micron - rho(sub 0.49)) channel is a quarter of that at 2.2 micron. Using this relationship, the surface reflectance in the visible channels can be predicted within Delta.rho(sub 0.49) approximately Delat.rho(sub 0.66) approximately 0.006 from rho(sub 2.2) for rho(sub 2.2) <= 0.10. This was half the error obtained using the 3.75 micron and corresponds to an error in aerosol optical thickness of Delat.tau approximately 0.06. These results, though applicable to several biomes (e.g. forests, and brighter lower canopies), have only been tested at one view angle - the nadir (theta = 0 deg). Considering the importance of the results in remote sensing of aerosols over land surfaces from space, we are validating the relationships for off-nadir view angles using Cloud Absorption Radiometer (CAR) data. The CAR data are available for channels between 0.3 and 2.3 micron and for different surface types and conditions: forest, tundra, ocean, sea-ice, swamp, grassland and over areas covered with smoke. In this study we analyzed data collected during the Smoke, Clouds, and Radiation - Brazil (SCAR-B) experiment to validate Kaufman et al.'s (1997) results for non-nadir view angles. We will show the correlation between rho(sub 0.472), rho(sub 0.675), and rho(sub 2.2) for view angles between nadir (0 deg) and 55 deg off-nadir, and for different viewing directions in the backscatter and forward scatter directions.

  6. Nadir Measurements of Carbon Monoxide Distributions by the Tropospheric Emission Spectrometer Instrument Onboard the Aura Spacecraft: Overview of Analysis Approach and Examples of Initial Results

    NASA Technical Reports Server (NTRS)

    Rinsland, Curtis P.; Luo, Ming; Logan, Jennifer A.; Beer, Reinhard; Worden, Helen; Kulawik, Susan S.; Rider, David; Osterman, Greg; Gunson, Michael; Eldering, Annmarie; Goldman, Aaron; Shephard, Mark; Clough, Shepard A.; Rodgers, Clive; Lampel, Michael; Chiou, Linda

    2006-01-01

    We provide an overview of the nadir measurements of carbon monoxide (CO) obtained thus far by the Tropospheric Emission Spectrometer (TES). The instrument is a high resolution array Fourier transform spectrometer designed to measure infrared spectral radiances from low Earth orbit. It is one of four instruments successfully launched onboard the Aura platform into a sun synchronous orbit at an altitude of 705 km on July 15, 2004 from Vandenberg Air Force Base, California. Nadir spectra are recorded at 0.06/cm spectral resolution with a nadir footprint of 5 x 8 km. We describe the TES retrieval approach for the analysis of the nadir measurements, report averaging kernels for typical tropical and polar ocean locations, characterize random and systematic errors for those locations, and describe instrument performance changes in the CO spectral region as a function of time. Sample maps of retrieved CO for the middle and upper troposphere from global surveys during December 2005 and April 2006 highlight the potential of the results for measurement and tracking of global pollution and determining air quality from space.

  7. Retrieval of CH4, CO, and CO2 total column amounts from SCIAMACHY near-infrared nadir spectra: retrieval algorithm and first results

    NASA Astrophysics Data System (ADS)

    Buchwitz, Michael; Burrows, John P.

    2004-02-01

    SCIAMACHY is a UV/visible/near-infrared grating spectrometer on board the European environmental satellite ENVISAT that observes the atmosphere in nadir, limb, and solar and lunar occultation viewing geometries with moderate spectral resolution (0.2-1.5 nm). At the University of Bremen a modified DOAS algorithm (WFM-DOAS) is being developed primarily for the retrieval of CH4, CO, CO2, H2O, N2O, and O2 total columns from SCIAMACHY near-infrared and visible nadir spectra. A first version of this algorithm has been implemented based on a fast look-up table approach. The algorithm and the look-up table is described along with an initial error analysis. Weighting functions and averaging kernels indicate that the SCIAMACHY near-infrared nadir measurements are highly sensitive to trace gas concentration changes even in the lowest kilometer of the atmosphere. The results presented have been obtained by applying WFM-DOAS to small spectral fitting windows focusing on CH4, CO2, CO, and O2 column retrieval and CH4 and CO2 to O2 column ratios (denoted XCH4 and XCO2, respectively). These type of data products are planned to be used within the EU research project EVERGREEN to constrain surface sources and sinks of CH4 and CO2 using inverse modeling techniques. This study discussed the first set of WFM-DOAS products generated for and to be further improved within EVERGREEN. Although no detailed validation has been performed yet we found that the retrieved columns have the right order of magnitude and show (at least qualitatively) the expected correlation of the well mixed gases CO2 and CH4 with O2 and surface topography. The standard deviation of the dry air column averaged mixing ration XCO2 within 10° latitude bands is +/-10 ppmv or 2.7% (XCH4: +/-50 ppbv or +/-2.8%) for measurements over land (over ocean the scatter is a factor of 2-4 larger). These values have been determined from ~25% of the ground pixels of one orbit which fulfill the following requirements: (nearly) cloud

  8. Recent Results on the CKM Angle Alpha

    SciTech Connect

    Mihalyi, A.; /Wisconsin U., Madison

    2005-10-18

    The method to measure the CKM angle {alpha} and the modes sensitive to it are discussed. It is shown that the B {yields} {rho}{rho} decays provide the most stringent constraint on {alpha}, which is found to be {alpha} = 96{sup o} {+-} 10{sup o}(stat) {+-} 4{sup o}(syst){+-} 13{sup o}(penguin).

  9. Reflectance anisotropy for nadir observations of coniferous forest canopies

    SciTech Connect

    Syren, P. . Lab. of Remote Sensing)

    1994-07-01

    Nadir-viewed reflectances from forest canopies in four spectral bands, centered at 485 nm, 654 nm, 841 nm, and 1,676 nm were measured at different sun angles. Reflectances were measured made from a helicopter ca. 10 km NE of Stockholm, Sweden, over mature and young stands of Scotch pine (Pinus sylvestris) and Norway spruce (Picea abies). The results show a significant increase in nadir reflectance with decreasing solar zenith angle. On the average, reflectance factors increased by 1--2% for each degree of decreasing solar zenith angle. Band ratios showed that there is a disproportional reflectance response in several of the spectral bands at varying zenith angles, differently expressed according to stand type and age. Within the solar zenith angle interval 30--70[degree], canopy reflectance was expressed as linear functions for each spectral band. These functions were used to calculate factors for reflectance standardization. Nomograms, containing reflectance correction factors for mature spruce stands, are presented. These can be directly applied in time-series analysis of multitemporal spectral data.

  10. Interpreting Negative Results in an Angle Maximization Problem.

    ERIC Educational Resources Information Center

    Duncan, David R.; Litwiller, Bonnie H.

    1995-01-01

    Presents a situation in which differential calculus is used with inverse trigonometric tangent functions to maximize an angle measure. A negative distance measure ultimately results, requiring a reconsideration of assumptions inherent in the initial figure. (Author/MKR)

  11. Preliminary Results from the Second EUVE Right Angle Program Catalog

    NASA Astrophysics Data System (ADS)

    Christian, D. J.; Craig, N.; Cahill, W. D.; Roberts, B.; Malina, R. F.

    1997-12-01

    We present preliminary results of our search for new sources in the EUVE Right Angle Program (RAP) data. The EUVE all-sky survey telescopes (also known as ``scanners'') are mounted at right angles to the Deep Survey and spectrometer instruments, and obtain photometric data in four bands centered at ~ 100 Angstroms (Lexan/B), ~ 200 Angstroms (Al/Ti/C), ~ 400 Angstroms (Ti/Sb/Al), and ~ 550 Angstroms (Sn/SiO). This allows the Right Angle Program to accumulate data serendipitously during pointed spectroscopic observations. The long exposure times possible with RAP observations provide much greater sensitivity than the all-sky survey. One-half of the scanner data since January 1994 has been analyzed, yielding approximately 200 new source detections. We present light-curves and variability measurements for the brighter sources. We have detected stellar flares from several yet to be identified sources. Source identifications and distribution by type will be also be presented.

  12. Review of weak mixing angle results at SLC and LEP

    SciTech Connect

    Woods, M.

    1995-10-01

    In this paper, the authors review recent precise measurements of the weak mixing angle by the SLD experiment at SLC and by the ALEPH, DELPHI, L3, and OPAL experiments at LEP. If they assume that the Minimal Standard Model provides a complete description of the quark and lepton couplings to the Z boson, they find sin{sup 2} {theta}{sub W}{sup eff} = 0.23143 {+-} 0.00028. If this assumption is relaxed to apply to lepton couplings only, they find sin{sup 2}{theta}{sub W}{sup eff} = 0.23106 {+-} 0.00035. They compare these results with other precision electroweak tests.

  13. Results from the G0 forward angle measurement

    SciTech Connect

    J. Liu

    2006-07-01

    The results from the G0 forward angle experiment are reported in this talk. The parity-violating asymmetry of elastic e-p scattering has been measured within the range of the four-momentum transfer (Q2) from 0.12 to 1.0 (GeV/c)2, which yields linear combinations of the strange electric and magnetic form factors of the nucleon, G{sub E}{sup s} + etaG{sub M}{sup s}, in the same Q2 range. The G0 results, combined with the measurements from other experiments, indicate that G{sub E}{sup s} and G{sub M}{sup s} are both likely non-zero.

  14. Inferring hemispherical reflectance of the earth's surface for global energy budgets from remotely sensed nadir or directional radiance values

    NASA Technical Reports Server (NTRS)

    Kimes, D. S.; Sellers, P. J.

    1985-01-01

    The relationship between directional reflectances spanning the entire reflecting hemisphere and hemispherical reflectance (albedo) and the effect of solar zenith angle and cover type on these relationships were investigated, using the results obtained from NOAA's 7/8 AVHRR ground-level reflectance measurements. Bands 1 (0.58-0.6B microns) and 2 (0.73-1. 1 microns) were used for reflectance measurements of 11 natural vegetation surfaces ranging from bare soils to dense vegetation canopies. The results show that errors in inferring hemispherical reflectance from nadir reflectance can be between 11 and 45 percent for all cover types and solar angles, depending on the viewing angles. A technique is described in which a choice of two specific view angles reduces this error to less than 6 percent for both bands and for all sun angles and cover types.

  15. Correction of Sampling Errors in Ocean Surface Cross-Sectional Estimates from Nadir-Looking Weather Radar

    NASA Technical Reports Server (NTRS)

    Caylor, I. Jeff; Meneghini, R.; Miller, L. S.; Heymsfield, G. M.

    1997-01-01

    The return from the ocean surface has a number of uses for airborne meteorological radar. The normalized surface cross section has been used for radar system calibration, estimation of surface winds, and in algorithms for estimating the path-integrated attenuation in rain. However, meteorological radars are normally optimized for observation of distributed targets that fill the resolution volume, and so a point target such as the surface can be poorly sampled, particularly at near-nadir look angles. Sampling the nadir surface return at an insufficient rate results in a negative bias of the estimated cross section. This error is found to be as large as 4 dB using observations from a high-altitude airborne radar. An algorithm for mitigating the error is developed that is based upon the shape of the surface echo and uses the returned signal at the three range gates nearest the peak surface echo.

  16. Preliminary Results of the Extreme Ultraviolet Explorer Right Angle Program

    NASA Astrophysics Data System (ADS)

    McDonald, K.; Craig, N.; Sirk, M. M.; Drake, J. J.; Malina, R. F.

    1993-12-01

    During the guest observer phase of the EUVE Mission, data are being collected with the survey scanners and the Deep Survey Scanner. The EUVE Right Angle Program (RAP) involves the analysis of this data set and the coordination of possible simultaneous observations with ground based instruments. This data set consists of several discrete pointings performed at a much deeper level than the previous EUVE all-sky survey, although covering only a few percent of the sky. Analysis of this data set has detected a large number of previously undetected EUV sources. We present here a preliminary list of the sources observed during the EUVE Right Angle Program and compare properties of this list with properties of the EUVE Bright Source List. This work has been supported by NASA contract NAS5--30180.

  17. Dust aerosol retrieval results from MISR (multi-angle imaging spectro-radiometer)

    NASA Technical Reports Server (NTRS)

    Kalashnikova, Olga V.; Diner, David J.; Kahn, Ralph; Gaitley, Barbara

    2004-01-01

    Satellite measurements provide important tools for understanding the effect of mineral dust aerosols on past and present climate and climate predictions. Multi-angle instruments such as Multi-angle Imaging Spectro- Radiometer (MISR) provide independent constraints on aerosol properties based on their sensitivity to the shape of aerosol scattering phase functions. The current MISR operational retrieval algorithm (version 16 and higher) was modified by incorporating new non-spherical dust models that account for naturally occurring dust shapes and compositions. We present selected examples of MISR version 16 retrievals over AERONET sunphotometer land and ocean sites during the passage of dust fronts. Our analysis shows that during such events MISR retrieves Angstrom exponents characteristic of large particles, having little spectral variation in extinction over the MISR wavelength range (442, 550, 672 and 866 nm channels), as expected. The retrieved fraction of non-spherical particles is also very high. This quantity is not retrieved by satellite instruments having only nadir-viewing cameras. Our comparison of current (version 16) MISR-retrieved aerosol optical thickness (AOT) with AERONET instantaneous AOT shows better coverage and stronger correlations than when making identical comparisons with previous AOT retrievals (version 15). The MISR algorithm successful mixtures include a non-spherical dust component with high frequency in retrievals over dark water and slightly lower frequency over land. Selection frequencies of non-spherical dust models also decrease in dusty regions affected by pollution.

  18. Tropospheric Ozone from limb nadir matching of MIPAS and SCIAMACHY

    NASA Astrophysics Data System (ADS)

    Rahpoe, Nabiz; Ebojie, Felix; Jia, Jia; Weber, Mark; Rozanov, Alexei; Bovensmann, Heinrich; Burrows, John P.; von Clarmann, Thomas; Stiller, Gabriele; Laeng, Alexandra; Lossow, Stefan

    2016-04-01

    The tropospheric total ozone column (TTOC) is retrieved by applying the limb nadir matching method (LNM) for two different sensors on board the Envisat satellite. Each sensor provides independent information of the total ozone column (TOC, nadir) and stratospheric ozone column (SOC, limb). The latter is derived from the limb viewing geometry of MIPAS (Michelson Interferometer for Passive Atmospheric Sounding), while total ozone column (TOC) from the nadir viewing SCIAMACHY (SCanning Imaging spectrometer for AtMospheric CHartrographY) measurements. The residual ozone column or tropospheric total ozone column (TTOC) is then derived by subtraction of the SOC from the collocated TOC. Although this method is straightforward, the underlying difficulties are the exact knowledge of the tropopause height, matching/collocation of the two measurements, and instrumental differences between two sensors. Our results are compared with available tropospheric ozone columns derived from the SCIAMACHY - SCIAMACHY limb-nadir combination in order to understand the differences and the potential of LNM method for different sensor combination.

  19. The Peruvian Continental Margin: Results from wide angle seismic Data

    NASA Astrophysics Data System (ADS)

    Krabbenhoeft, A.; Bialas, J.; Kopp, H.; Kukowski, N.; Huebscher, C.

    2003-04-01

    Within the scope of the GEOPECO (Geophysical Experiments at the Peruvian Continental Margin) project, seismic investigations along the Pacific margin of Peru were carried out using ocean bottom hydrophones (OBH) and seismometers (OBS) recording marine airgun shots. The structure and the P- wave velocity of the oblique subducting Nazca and overriding South-American Plates from 8°S to 15°S were determined by forward modeling and tomographic inversion of the wide-angle seismic data combined with the analysis of reflection seismic data. The region south of 12°S has been influenced by the southward migration of the aseismic Nazca Ridge the past 11 Ma. The oceanic Nazca Plate is divided by Mendana Fracture Zone (MFZ) which marks a transition zone of a different crustal age of approximately 28 Ma in the north to 38 Ma in the south at the Peruvian trench. North of MFZ the oceanic crust is influenced by Trujillo Trough trending N15E and the surrounding extensional stresses leading to a crustal thinning as can be seen in the northernmost refraction seismic model. The oceanic crust south of MFZ is overall homogeneous with a thin pelagic sedimentary layer and normal oceanic crustal layers. The P-wave velocity of the mantle is overall 7.9-8.1km/s. The Peruvian Continental Margin is characterized by the continental slope and several basins, Trujillo and Yaquina basin, Lima basin and Pisco basin, which are partly affected by the southward migration of the subducting Nazca Ridge. This caused uplift and subsidence along the margin leading to erosional tectonic features. The basins and continental basement could be mapped with forward modeling and tomographic inversion as well as the continental backstop on each profile. An accretionary prism is set up with a width of 20 to 30 km and 4 to 5 km thickness which does not further increase in size as revealed by the profiles recorded further north of Nazca Ridge. This and a taper of 14- 17 degrees at the collision zone indicates that

  20. Flight Test Results of an Angle of Attack and Angle of Sideslip Calibration Method Using Output-Error Optimization

    NASA Technical Reports Server (NTRS)

    Siu, Marie-Michele; Martos, Borja; Foster, John V.

    2013-01-01

    As part of a joint partnership between the NASA Aviation Safety Program (AvSP) and the University of Tennessee Space Institute (UTSI), research on advanced air data calibration methods has been in progress. This research was initiated to expand a novel pitot-static calibration method that was developed to allow rapid in-flight calibration for the NASA Airborne Subscale Transport Aircraft Research (AirSTAR) facility. This approach uses Global Positioning System (GPS) technology coupled with modern system identification methods that rapidly computes optimal pressure error models over a range of airspeed with defined confidence bounds. Subscale flight tests demonstrated small 2-s error bounds with significant reduction in test time compared to other methods. Recent UTSI full scale flight tests have shown airspeed calibrations with the same accuracy or better as the Federal Aviation Administration (FAA) accepted GPS 'four-leg' method in a smaller test area and in less time. The current research was motivated by the desire to extend this method for inflight calibration of angle of attack (AOA) and angle of sideslip (AOS) flow vanes. An instrumented Piper Saratoga research aircraft from the UTSI was used to collect the flight test data and evaluate flight test maneuvers. Results showed that the output-error approach produces good results for flow vane calibration. In addition, maneuvers for pitot-static and flow vane calibration can be integrated to enable simultaneous and efficient testing of each system.

  1. Bidirectional measurements of surface reflectance for view angle corrections of oblique imagery

    NASA Technical Reports Server (NTRS)

    Jackson, R. D.; Teillet, P. M.; Slater, P. N.; Fedosejevs, G.; Jasinski, Michael F.

    1990-01-01

    An apparatus for acquiring bidirectional reflectance-factor data was constructed and used over four surface types. Data sets were obtained over a headed wheat canopy, bare soil having several different roughness conditions, playa (dry lake bed), and gypsum sand. Results are presented in terms of relative bidirectional reflectance factors (BRFs) as a function of view angle at a number of solar zenith angles, nadir BRFs as a function of solar zenith angles, and, for wheat, vegetation indices as related to view and solar zenith angles. The wheat canopy exhibited the largest BRF changes with view angle. BRFs for the red and the NIR bands measured over wheat did not have the same relationship with view angle. NIR/Red ratios calculated from nadir BRFs changed by nearly a factor of 2 when the solar zenith angle changed from 20 to 50 degs. BRF versus view angle relationships were similar for soils having smooth and intermediate rough surfaces but were considerably different for the roughest surface. Nadir BRF versus solar-zenith angle relationships were distinctly different for the three soil roughness levels. Of the various surfaces, BRFs for gypsum sand changed the least with view angle (10 percent at 30 degs).

  2. Near-Nadir Radar Backscatter From Ocean Waves

    NASA Technical Reports Server (NTRS)

    Glazman, Roman E.

    1992-01-01

    Paper discusses aspects of theory of near-nadir radar backscatter from well-developed sea. Study contributed to development of new technique for determination of sea-state bias in satellite altimeter measurements. Paper questions assumptions, bringing accepted interpretation of nadir and near-nadir radar backscattering into doubt.

  3. Impact of Footprint Diameter and Off-Nadir Pointing on the Precision of Canopy Height Estimates from Spaceborne Lidar

    NASA Technical Reports Server (NTRS)

    Pang, Yong; Lefskky, Michael; Sun, Guoqing; Ranson, Jon

    2011-01-01

    A spaceborne lidar mission could serve multiple scientific purposes including remote sensing of ecosystem structure, carbon storage, terrestrial topography and ice sheet monitoring. The measurement requirements of these different goals will require compromises in sensor design. Footprint diameters that would be larger than optimal for vegetation studies have been proposed. Some spaceborne lidar mission designs include the possibility that a lidar sensor would share a platform with another sensor, which might require off-nadir pointing at angles of up to 16 . To resolve multiple mission goals and sensor requirements, detailed knowledge of the sensitivity of sensor performance to these aspects of mission design is required. This research used a radiative transfer model to investigate the sensitivity of forest height estimates to footprint diameter, off-nadir pointing and their interaction over a range of forest canopy properties. An individual-based forest model was used to simulate stands of mixed conifer forest in the Tahoe National Forest (Northern California, USA) and stands of deciduous forests in the Bartlett Experimental Forest (New Hampshire, USA). Waveforms were simulated for stands generated by a forest succession model using footprint diameters of 20 m to 70 m. Off-nadir angles of 0 to 16 were considered for a 25 m diameter footprint diameter. Footprint diameters in the range of 25 m to 30 m were optimal for estimates of maximum forest height (R(sup 2) of 0.95 and RMSE of 3 m). As expected, the contribution of vegetation height to the vertical extent of the waveform decreased with larger footprints, while the contribution of terrain slope increased. Precision of estimates decreased with an increasing off-nadir pointing angle, but off-nadir pointing had less impact on height estimates in deciduous forests than in coniferous forests. When pointing off-nadir, the decrease in precision was dependent on local incidence angle (the angle between the off-nadir

  4. NADIR: A Flexible Archiving System Current Development

    NASA Astrophysics Data System (ADS)

    Knapic, C.; De Marco, M.; Smareglia, R.; Molinaro, M.

    2014-05-01

    The New Archiving Distributed InfrastructuRe (NADIR) is under development at the Italian center for Astronomical Archives (IA2) to increase the performances of the current archival software tools at the data center. Traditional softwares usually offer simple and robust solutions to perform data archive and distribution but are awkward to adapt and reuse in projects that have different purposes. Data evolution in terms of data model, format, publication policy, version, and meta-data content are the main threats to re-usage. NADIR, using stable and mature framework features, answers those very challenging issues. Its main characteristics are a configuration database, a multi threading and multi language environment (C++, Java, Python), special features to guarantee high scalability, modularity, robustness, error tracking, and tools to monitor with confidence the status of each project at each archiving site. In this contribution, the development of the core components is presented, commenting also on some performance and innovative features (multi-cast and publisher-subscriber paradigms). NADIR is planned to be developed as simply as possible with default configurations for every project, first of all for LBT and other IA2 projects.

  5. Resonant scattering and resultant pitch angle evolution of relativistic electrons by plasmaspheric hiss

    NASA Astrophysics Data System (ADS)

    Ni, B.; Bortnik, J.; Thorne, R. M.; Ma, Q.; Chen, L.

    2013-12-01

    Adopting several realistic models for the wave distribution and ambient plasmaspheric density, we perform a comprehensive analysis to evaluate hiss-induced scattering coefficients, the relative role of each resonant harmonic, and the overall effect of hiss scattering on the pitch angle evolution and associated decay (loss) processes of relativistic electrons. The results show that scattering by the equatorial, highly oblique component of the hiss emission is negligible. A quasi-parallel propagating wave model of hiss emissions provides a good approximation for evaluation of scattering rates of ≤ 2 MeV electrons. However, realistic wave propagation angles as a function of latitude along the field line must be taken into account to accurately quantify the rates of hiss scattering above 2 MeV. Ambient plasma density is also a critical parameter that can influence hiss scattering rates and resultant pitch angle evolution of electron flux. While the first order cyclotron and the Landau resonances are dominant for hiss-induced scattering of less than 2 MeV electrons, higher order resonances become important and even dominant at intermediate equatorial pitch angles for ultra-relativistic (≥ 3 MeV) electrons. Hiss induced electron pitch angle evolution consistently shows a relatively rapid initial transport of electrons from high to lower pitch angles, with a gradual approach towards an equilibrium shape, and a final state where the entire distribution decays exponentially with time. Although hiss scattering rates near the loss cone control the pitch angle evolution and the ultimate loss of ultra-relativistic electrons, the presence of a scattering bottleneck (a pronounced drop in diffusion rate at intermediate pitch angles) significantly affects the loss rate and leads to characteristic top hat shaped pitch angle distributions at energies below ~1 MeV. Decay timescales are determined to be on the order of a few days, tens of days, and > 100 days for 500 keV, 2 Me

  6. Satellite navigation for meteorological purposes: Inverse referencing for NOAA-N and ERS-1 imagers with a 1 km nadir pixel size

    NASA Astrophysics Data System (ADS)

    Klokočník, J.; Kostelecký, J.; Grassl, H.; Schlüssel, P.; Pospíšilová, L.; Gooding, R. H.; Lála, P.

    Iterative methods for inverse referencing from mean orbital elements or osculating position and velocity, accounting for all necessary orbital perturbations with respect to given nadir pixel size, are described. [Inverse referencing means that the geodetic coordinates of a point on the surface are given and the corresponding image coordinates (scan line number and pixel number) are obtained from satellite orbital elements or coordinates.] The idea is to treat a pixel like a satellite tracking station on the ground. This permits the use of existing software for the computation of satellite ephemerides and orbit determination. The time of culmination of a satellite over the pixel and the off-nadir angle at that moment have been computed. Two variants for such a computation have been tested. Numerical results for the NOAA-N meteorological satellites and ERS-1 are presented. The present state of our software for inverse referencing should fulfil ordinary requirements posed by meteorologists. For NOAA-N satellites, the accuracy achieved roughly the nadir pixel size. The main obstacle to an increase in accuracy is the low quality of the mean orbital elements usually available. For ERS-1, the accuracy may achieve a level of 100 m. A software package, containing versions of the FORTRAN 77 programs PIXPO 3, PIXPO 4 and PIXPOSC, for various data types, including US-2 line or TBUS mean elements or a state vector, is available for scientific exchange.

  7. Preliminary results from an airdata enhancement algorithm with application to high-angle-of-attack flight

    NASA Technical Reports Server (NTRS)

    Moes, Timothy R.; Whitmore, Stephen A.

    1991-01-01

    A technique was developed to improve the fidelity of airdata measurements during dynamic maneuvering. This technique is particularly useful for airdata measured during flight at high angular rates and high angles of attack. To support this research, flight tests using the F-18 high alpha research vehicle (HARV) were conducted at NASA Ames Research Center, Dryden Flight Research Facility. A Kalman filter was used to combine information from research airdata, linear accelerometers, angular rate gyros, and attitude gyros to determine better estimates of airdata quantities such as angle of attack, angle of sideslip, airspeed, and altitude. The state and observation equations used by the Kalman filter are briefly developed and it is shown how the state and measurement covariance matrices were determined from flight data. Flight data are used to show the results of the technique and these results are compared to an independent measurement source. This technique is applicable to both postflight and real-time processing of data.

  8. Estimating spectral albedo and nadir reflectance through inversion of simple BRDF models with AVHRR/MODIS-like data

    NASA Astrophysics Data System (ADS)

    Privette, Jeffrey L.; Eck, Thomas F.; Deering, Donald W.

    1997-12-01

    In recent years, many computationally efficient bidirectional reflectance models have been developed to account for angular effects in land remote sensing data, particularly those from the NOAA advanced very high resolution radiometer (AVHRR), polarization and directionality of the Earth's reflectances (POLDER), and the planned EOS moderate-resolution imaging spectrometer (MODIS) and multi-angle imaging spectroradiometer (MISR) sensors. In this study, we assessed the relative ability of 10 such models to predict commonly used remote sensing products (nadir reflectance and albedo). Specifically, we inverted each model with ground-based data from the portable apparatus for rapid acquisition of bidirectional observations of the land and atmosphere (PARABOLA) arranged in subsets representative of satellite sampling geometries. We used data from nine land cover types, ranging from soil to grassland (First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE)) to forest (Boreal Ecosystem-Atmosphere Study (BOREAS)). Retrieved parameters were used in forward model runs to estimate nadir reflectance and spectral albedo over a wide range of solar angles. We rank the models by the accuracy of the estimated products and find results to be strongly dependent on the view azimuth angle range of the inversion data, and less dependent on the spectral band and land cover type. Overall, the nonlinear model of Rahman et al. [993] and the linear kernel-driven RossThickLiSparse model [Wanner et al., 1995] were most accurate. The latter was at least 25 times faster to invert than the former. Interestingly, we found these two models were not able to match the various bidirectional reflectance distribution function (BRDF) shapes as well as other models, suggesting their superior performance lies in their ability to be more reliably inverted with sparse data sets. These results should be useful to those interested in the computationally fast normalization

  9. Polypeptide motions are dominated by peptide group oscillations resulting from dihedral angle correlations between nearest neighbors.

    PubMed

    Fitzgerald, James E; Jha, Abhishek K; Sosnick, Tobin R; Freed, Karl F

    2007-01-23

    To identify basic local backbone motions in unfolded chains, simulations are performed for a variety of peptide systems using three popular force fields and for implicit and explicit solvent models. A dominant "crankshaft-like" motion is found that involves only a localized oscillation of the plane of the peptide group. This motion results in a strong anticorrelated motion of the phi angle of the ith residue (phi(i)) and the psi angle of the residue i - 1 (psi(i-1)) on the 0.1 ps time scale. Only a slight correlation is found between the motions of the two backbone dihedral angles of the same residue. Aside from the special cases of glycine and proline, no correlations are found between backbone dihedral angles that are separated by more than one torsion angle. These short time, correlated motions are found both in equilibrium fluctuations and during the transit process between Ramachandran basins, e.g., from the beta to the alpha region. A residue's complete transit from one Ramachandran basin to another, however, occurs in a manner independent of its neighbors' conformational transitions. These properties appear to be intrinsic because they are robust across different force fields, solvent models, nonbonded interaction routines, and most amino acids. PMID:17223689

  10. An improved tropospheric ozone database retrieved from SCIAMACHY Limb-Nadir-Matching method

    NASA Astrophysics Data System (ADS)

    Jia, Jia; Rozanov, Alexei; Ladstätter-Weißenmayer, Annette; Ebojie, Felix; Rahpoe, Nabiz; Bötel, Stefan; Burrows, John

    2015-04-01

    Tropospheric ozone is one of the most important green-house gases and the main component of photochemical smog. It is either transported from the stratosphere or photochemically produced during pollution events in the troposphere that threaten the respiratory system. To investigate sources, transport mechanisms of tropospheric ozone in a global view, limb nadir matching (LNM) technique applied with SCIAMACHY instrument is used to retrieve tropospheric ozone. With the fact that 90% ozone is located in the stratosphere and only about 10% can be observed in the troposphere, the usage of satellite data requires highly qualified nadir and limb data. In this study we show an improvement of SCIAMACHY limb data as well as its influence on tropospheric ozone results. The limb nadir matching technique is also refined to increase the quality of the tropospheric ozone. The results are validated with ozone sonde measurements.

  11. Determination of Optimum Viewing Angles for the Angular Normalization of Land Surface Temperature over Vegetated Surface

    PubMed Central

    Ren, Huazhong; Yan, Guangjian; Liu, Rongyuan; Li, Zhao-Liang; Qin, Qiming; Nerry, Françoise; Liu, Qiang

    2015-01-01

    Multi-angular observation of land surface thermal radiation is considered to be a promising method of performing the angular normalization of land surface temperature (LST) retrieved from remote sensing data. This paper focuses on an investigation of the minimum requirements of viewing angles to perform such normalizations on LST. The normally kernel-driven bi-directional reflectance distribution function (BRDF) is first extended to the thermal infrared (TIR) domain as TIR-BRDF model, and its uncertainty is shown to be less than 0.3 K when used to fit the hemispheric directional thermal radiation. A local optimum three-angle combination is found and verified using the TIR-BRDF model based on two patterns: the single-point pattern and the linear-array pattern. The TIR-BRDF is applied to an airborne multi-angular dataset to retrieve LST at nadir (Te-nadir) from different viewing directions, and the results show that this model can obtain reliable Te-nadir from 3 to 4 directional observations with large angle intervals, thus corresponding to large temperature angular variations. The Te-nadir is generally larger than temperature of the slant direction, with a difference of approximately 0.5~2.0 K for vegetated pixels and up to several Kelvins for non-vegetated pixels. The findings of this paper will facilitate the future development of multi-angular thermal infrared sensors. PMID:25825975

  12. Results from Core-collapse Simulations with Multi-dimensional, Multi-angle Neutrino Transport

    NASA Astrophysics Data System (ADS)

    Brandt, Timothy D.; Burrows, Adam; Ott, Christian D.; Livne, Eli

    2011-02-01

    We present new results from the only two-dimensional multi-group, multi-angle calculations of core-collapse supernova evolution. The first set of results from these calculations was published in 2008 by Ott et al. We have followed a nonrotating and a rapidly rotating 20 M sun model for ~400 ms after bounce. We show that the radiation fields vary much less with angle than the matter quantities in the region of net neutrino heating. This happens because most neutrinos are emitted from inner radiative regions and because the specific intensity is an integral over sources from many angles at depth. The latter effect can only be captured by multi-angle transport. We then compute the phase relationship between dipolar oscillations in the shock radius and in matter and radiation quantities throughout the post-shock region. We demonstrate a connection between variations in neutrino flux and the hydrodynamical shock oscillations, and use a variant of the Rayleigh test to estimate the detectability of these neutrino fluctuations in IceCube and Super-Kamiokande. Neglecting flavor oscillations, fluctuations in our nonrotating model would be detectable to ~10 kpc in IceCube, and a detailed power spectrum could be measured out to ~5 kpc. These distances are considerably lower in our rapidly rotating model or with significant flavor oscillations. Finally, we measure the impact of rapid rotation on detectable neutrino signals. Our rapidly rotating model has strong, species-dependent asymmetries in both its peak neutrino flux and its light curves. The peak flux and decline rate show pole-equator ratios of up to ~3 and ~2, respectively.

  13. Post-launch performance evaluation of the OMPS Nadir Mapper and Nadir Profiler

    NASA Astrophysics Data System (ADS)

    Grotenhuis, Michael G.; Wu, Xiangqian; Flynn, Larry; Beach, Eric; Niu, Jianguo; Yu, Wei

    2014-09-01

    The Joint Polar Satellite System (JPSS) represents the latest generation of polar-orbiting satellites operated by the National Oceanic and Atmospheric Administration (NOAA). The first in the JPSS series of satellites, the Suomi National Polar-orbiting Partnership (NPP) spacecraft was launched in November 2011 to bridge the gap between the current Polar Operational Environmental Satellites (POES) and the future JPSS-1. The Ozone Mapping Profiler Suite (OMPS) is a suite of hyperspectral instruments onboard the Suomi NPP spacecraft designed to continue atmospheric ozone records through both atmospheric profiles and global distribution mapping. OMPS will also be included on the future JPSS payloads. In order to properly extend measurements from previous ozone instruments, including the Solar Backscatter Ultraviolet (SBUV) instrument on POES, proper OMPS calibration is necessary. In this study, the postlaunch performance of the OMPS Nadir Mapper (NM) and Nadir Profiler (NP) are evaluated through their Sensor Data Records (SDRs), which validates their end-to-end calibration. This is achieved through stability monitoring and intercomparison.

  14. Aerosol measurements in the IR: from limb to nadir?

    NASA Technical Reports Server (NTRS)

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

    2001-01-01

    Vertical profiles of aerosol concentration have been derived from the ATMOS solar occultation dataset. The EOS instrument TES has motivated studies of the feasibility of quantifying aerosols in nadir and limb emission measurements.

  15. Evaluating Orbiting Carbon Observatory 2 (OCO-2) Nadir and Glint Observing Sequences

    NASA Astrophysics Data System (ADS)

    Nassar, R.; Deng, F.; Polavarapu, S.; Neish, M.; Jones, D. B. A.; O'Dell, C.

    2014-12-01

    NASA's Orbiting Carbon Observatory 2 (OCO-2) mission successfully launched on July 2, 2014. OCO-2 measures spectra of reflected solar radiation from the Earth's surface, which are used to derive high precision column-averaged CO2 mole fractions (XCO2). OCO-2 will alternate between nadir and glint mode every 16 days (233 orbits) with occasional target observations primarily for calibration and validation. Nadir mode typically has better signal-to-noise ratio (SNR) over land and the highest probability of avoiding clouds, but poor SNR over water. Glint mode yields good SNR over water (from the specular reflectance of solar radiation) and land, but glint observations are more susceptible to encountering clouds due to their longer paths through the atmosphere, especially at high solar zenith angles. Is there a quantifiable benefit to cycling between nadir and glint more frequently or increasing the fraction of observations from either mode? This question is investigated by generating synthetic OCO-2 observations for the baseline observing sequence (16-day nadir/glint) and by more frequent alternation (per orbit). Observation distributions (after application of filters) demonstrate the different coverage obtained by the two observing scenarios on a 16-day scale. A forward CO2 simulation of the Environment Canada Carbon Assimilation System (EC-CAS) is designated as the 'truth' in an Observing System Simulation Experiment (OSSE) and sampled with the observational coverage from each observing sequence, yielding two sets of synthetic XCO2 observations. The GEOS-Chem CO2 adjoint is used to evaluate the ability of the different synthetic datasets to constrain surface CO2 fluxes. The combination of two model systems in this OSSE enables assessment of the sensitivity of the fluxes to transport errors as well as biases in the OCO-2 observations, leading to a more robust overall assessment of the strengths and weakness of the two observing sequences.

  16. Structured water in polyelectrolyte dendrimers: Understanding small angle neutron scattering results through atomistic simulation

    SciTech Connect

    Chen, Wei-Ren; Do, Changwoo; Hong, Kunlun; Liu, Emily; Liu, Yun; Porcar, L.; Smith, Gregory Scott; Wu, Bin; Egami, T; Smith, Sean C

    2012-01-01

    Based on atomistic molecular dynamics (MD) simulations, the small angle neutron scattering (SANS) intensity behavior of a single generation-4 (G4) polyelectrolyte polyamidoamine (PAMAM) starburst dendrimer is investigated at different levels of molecular protonation. The SANS form factor, P(Q), and Debye autocorrelation function, (r), are calculated from the equilibrium MD trajectory based on a mathematical approach proposed in this work which provides a link between the neutron scattering experiment and MD computation. The simulations enable scattering calculations of not only the hydrocarbons, but also the contribution to the scattering length density fluctuations caused by structured, confined water within the dendrimer. Based on our computational results, we question the validity of using radius of gyration RG for microstructure characterization of a polyelectrolyte dendrimer from the scattering perspective.

  17. Lateral and axial resolutions of an angle-deviation microscope for different numerical apertures: experimental results

    NASA Astrophysics Data System (ADS)

    Chiu, Ming-Hung; Lai, Chin-Fa; Tan, Chen-Tai; Lin, Yi-Zhi

    2011-03-01

    This paper presents a study of the lateral and axial resolutions of a transmission laser-scanning angle-deviation microscope (TADM) with different numerical aperture (NA) values. The TADM is based on geometric optics and surface plasmon resonance principles. The surface height is proportional to the phase difference between two marginal rays of the test beam, which is passed through the test medium. We used common-path heterodyne interferometry to measure the phase difference in real time, and used a personal computer to calculate and plot the surface profile. The experimental results showed that the best lateral and axial resolutions for NA = 0.41 were 0.5 μm and 3 nm, respectively, and the lateral resolution breaks through the diffraction limits.

  18. PITCH-ANGLE SCATTERING: RESONANCE VERSUS NONRESONANCE, A BASIC TEST OF THE QUASILINEAR DIFFUSIVE RESULT

    SciTech Connect

    Ragot, B. R.

    2012-01-01

    Due to the very broad range of the scales available for the development of turbulence in space and astrophysical plasmas, the energy at the resonant scales of wave-particle interaction often constitutes only a tiny fraction of the total magnetic turbulent energy. Despite the high efficiency of resonant wave-particle interaction, one may therefore question whether resonant interaction really is the determining interaction process between particles and turbulent fields. By evaluating and comparing resonant and nonresonant effects in the frame of a quasilinear calculation, the dominance of resonance is here put to the test. By doing so, a basic test of the classical resonant quasilinear diffusive result for the pitch-angle scattering of charged energetic particles is also performed.

  19. NO2 from SCIAMACHY limb and nadir measurements - validation of the operational data products

    NASA Astrophysics Data System (ADS)

    Azam, Faiza; Weigel, Katja; Weber, Mark; Rozanov, Alexei; Bovensmann, Heinrich; Burrows, John P.

    2014-05-01

    SCanning Imaging Absorption spectroMeter for Atmospheric CHartograpY (SCIAMACHY), aboard Envisat, 2002-2012, observed the transmitted, scattered and reflected solar radiation from the earth's atmosphere in limb, nadir and solar/lunar occultation geometries covering UV-Visible to NIR (240-2830 nm) spectral range with a moderate spectral resolution of 0.2-1.5nm. Monitoring the stability and verifying the quality of its decadal scale products is a prerequisite to their usage for long term analysis and interpretations, as well as stratospheric ozone studies and assessments. With this perspective, the ESA project SCILOV-10 (SCIAMACHY long term validation 2010) aims at the lifetime validations and documentation of the quality of various operational data products retrieved from SCIAMACHY in limb and nadir geometries. The limb observations provide vertically resolved global coverage and the nadir measurements give vertical column amounts on the same coverage scale. NO2 plays an important role in the stratospheric ozone chemistry by controlling the ozone abundances through catalytic destruction or by mitigating ozone depletion through reservoir formation. In the troposphere its concentration determines the ozone amount. Here we present the validation results of the operational limb stratospheric NO2 profiles and the nadir NO2 total column products. The limb dataset is compared with the corresponding scientific SCIAMACHY retrievals at the Institute of Environmental Physics (IUP) Bremen and with correlative measurements form other satellites as ACE-FTS, HALOE, SAGE II and OSIRIS. The nadir product is validated with the corresponding IUP measurements and with GOME NO2 data product.

  20. The TOMS V9 Algorithm for OMPS Nadir Mapper Total Ozone: An Enhanced Design That Ensures Data Continuity

    NASA Astrophysics Data System (ADS)

    Haffner, D. P.; McPeters, R. D.; Bhartia, P. K.; Labow, G. J.

    2015-12-01

    The TOMS V9 total ozone algorithm will be applied to the OMPS Nadir Mapper instrument to supersede the exisiting V8.6 data product in operational processing and re-processing for public release. Becuase the quality of the V8.6 data is already quite high, enchancements in V9 are mainly with information provided by the retrieval and simplifcations to the algorithm. The design of the V9 algorithm has been influenced by improvements both in our knowledge of atmospheric effects, such as those of clouds made possible by studies with OMI, and also limitations in the V8 algorithms applied to both OMI and OMPS. But the namesake instruments of the TOMS algorithm are substantially more limited in their spectral and noise characterisitics, and a requirement of our algorithm is to also apply the algorithm to these discrete band spectrometers which date back to 1978. To achieve continuity for all these instruments, the TOMS V9 algorithm continues to use radiances in discrete bands, but now uses Rodgers optimal estimation to retrieve a coarse profile and provide uncertainties for each retrieval. The algorithm remains capable of achieving high accuracy results with a small number of discrete wavelengths, and in extreme cases, such as unusual profile shapes and high solar zenith angles, the quality of the retrievals is improved. Despite the intended design to use limited wavlenegths, the algorithm can also utilitze additional wavelengths from hyperspectral sensors like OMPS to augment the retreival's error detection and information content; for example SO2 detection and correction of Ring effect on atmospheric radiances. We discuss these and other aspects of the V9 algorithm as it will be applied to OMPS, and will mention potential improvements which aim to take advantage of a synergy with OMPS Limb Profiler and Nadir Mapper to further improve the quality of total ozone from the OMPS instrument.

  1. Results of trench perpendicular wide angle seismic transects across the Manila subduction zone offshore southern Taiwan

    NASA Astrophysics Data System (ADS)

    Eakin, D. H.; McIntosh, K. D.; Van Avendonk, H. J.

    2011-12-01

    Multi-channel seismic reflection and wide-angle seismic data collected in 2009 aboard the R/V Marcus Langseth as part of the TAIGER program delineate the crustal structure of the Manila subduction zone in the northern South China Sea. As part of that project, we recorded marine seismic data using a deployment of ocean-bottom-seismometers (OBS) from the U.S. instrument pool and National Taiwan Ocean University. The region between northern Luzon and southern Taiwan evolves from oceanic subduction to incipient arc-continent collision. This presentation focuses on results of 2 offshore transects across the Manila subduction zone offshore southern Taiwan. Our goal here is to document the transition from pure oceanic subuction in the south to incipient arc-continent collision in the north, an understanding of which is integral for future geodynamic modeling of the advanced arc-continent collision in the north. The northern transect, line T2 is located at 21.4° N and used 30 OBSs. Line T1 was located at 20.5° N and used 27 OBSs across the Manila subduction zone. Data quality is extremely variable due to the local geology and quality of seafloor coupling at each instrument. Preliminary travel-time tomography of transect T2 shows a 10-15 km thick Eurasian crust with crustal velocities of 5-7.5 km/sec entering the Manila trench suggesting thinned continental crust, serpentinized upper mantle, or both in this region. The model shows the accretionary prism to be cored by high velocity material (6-7 km/sec) that may be the result of accretion of crustal material from the subducting Eurasian slab. We also observe asymmetric crustal thickening beneath the Gagua Ridge that is potentially a result of failed subduction of the Philippine Sea Plate westward along the Gagua Ridge. The wide-angle data is complimented by MCS reflection data to constrain sediment thickness, top of the crystalline basement, and moho. Preliminary work is in progress with transect T1 which will be

  2. Interpreting vegetation reflectance measurements as a function of solar zenith angle

    NASA Technical Reports Server (NTRS)

    Kimes, D. S.; Smith, J. A.; Ranson, K. J.

    1979-01-01

    Spectral hemispherical-conical reflectances of a nadir looking sensor were taken throughout the day for a lodgepole pine and two grass canopies. Mathematical simulations of both spectral hemispherical-conical and bi-hemispherical reflectances were performed for two theoretical canopies of contrasting geometric structure. These results and comparisons with literature studies showed a great amount of variability of vegetation canopy reflectances as a function of solar zenith angle. Explanations for this variability are discussed and recommendations for further measurements are proposed.

  3. Seismogenic Processes In The Nankai Trough: Results Form Wide-angle Seismic Surveys

    NASA Astrophysics Data System (ADS)

    Kodaira, S.; Nakanishi, A.; Park, J.-O.; Kaneda, Y.

    Active seismic studies to reveal the seismogenic zone structure have been widely car- ried out in the Nankai trough since the last five years. A subducted seamount colliding to the Japanese island arc crust was successfully imaged off the cape Muroto by an extensive active seismic survey. This subducted seamount is proposed as a barrier preventing a lateral propagation of the co-seismic rupture during the 1946 Nankaido Earthquake. In terms of the rupture process of the 1944 Nankaido Earthquake, both seismic and tsunami data (Kikuchi and Yamanaka, 2001; Tanioka and Satake, 1999) show the co-seismic ruptures were concentrated at the east of the Kii peninsula and did not extend to the Tokai district. Historic earthquake data also show that a recur- rence interval of the mega-thrust earthquakes off the Tokai district is not as regular as at other areas in the Nankai Trough. A key question is, therefore, if there is signifi- cant structural factor to prevent the rupture in this area. Even though it is proposed the Paleo-Zenisu ridge might be subducted in the eastern Nankai trough, no clear seismic image has been obtained. In July to August of 2001, an active seismic study using a super densely deployed OBS array was performed, as a part of an onshore-offshore wide-angle seismic survey, off the Tokai district. Results of first arrival tomography of the wide-angle seismic data show following structures: i) root of the Zenisu ridge ex- tends down to 15-20 km depth consisting of thicker lower crustal body (Vp = 6.6 - 7.4 km/s), ii) slightly thickening of subducted oceanic crust is recognized at immediately landward the Nankai trough suggesting the possible Paleo-Zenisu ridge. But, crustal volume of the Paleo-Zenisu might be significantly smaller than the present day Zenisu ridge, iii) abrupt thickening of middle (Vp =6.0 - 6.4 km/s) and lower (Vp=6.6-7.4 km/s) crust toward the Izu island arc is observed at the southern end of the profile. The structure representing the

  4. First Results Obtained with Wide-Angle Cerenkov Light Telescope BEO p. Mussala

    NASA Astrophysics Data System (ADS)

    Slavcheva Malamova, E.; Angelov, I.; Davidkov, K.; Stamenov, J.; Kirov, I.

    2003-07-01

    The first results from experiment using Cerenkov light of EAS, reflected from the snow surface of Ice Lake p. Mussala, Bulgaria are described. The construction of the telescope was started in autumn 2000.The first measurements with 1-meter diameter reflectors and FEU110 were carried out in winter 2000-2001. During 2002-2003 the detector was improved. The first results obtained in winter 2002-2003 are presented in this paper. Introduction Our experiment is based on the Prof. A.E. Chudakov (1972)[1] idea to detect the Cerenkov light from EAS reflected by snow surface.The special feature of that method is the possibility to use a sensitive area over some hundred square kilometers with comparatively small detectors. The intensity of Cerenkov light from EAS is proportional to the energy of the primary cosmic ray particle so this method is a calorimetric one. It gives the possibility for experimental investigation of the primary spectrum of the cosmic rays with very and ultra high energies. The Basic Environmental Observatory on peak Mussala (2925-m a.s.l) provides a real opportunity for realization of that method. The Ice Lake is located in the Mussala circus region, at 200 m below the peak (2925-m a.s.l). The lake's area is approximately 20.103 m2 . Its surface retains an ice-cover approximately 7 to 8 months annually. Detector is situated on the 212m high mountain ledge nearby Ice Lake and registers the Cerenkov light of the air showers reflected from the snow surface of the lake.The limits of the zenith angle for the photons descended by the reflecting surface, are determined by the terrain's specifics: d=0.73 rad The detector setting up consists of two parab olic reflectors with 1.40-meter diameter each. The light spots are detected by two photomultipliers (FEU-49B),

  5. Postlaunch Performance of the Suomi National Polar-Orbiting Partnership Ozone Mapping and Profiler Suite (OMPS) Nadir Sensors

    NASA Technical Reports Server (NTRS)

    Seftor, C. J.; Jaross, G.; Kowitt, M.; Haken, M.; Li, J.; Flynn, L. E.

    2014-01-01

    The prelaunch specifications for nadir sensors of the Ozone Mapping and Profiler Suite (OMPS) were designed to ensure that measurements from them could be used to retrieve total column ozone and nadir ozone profile information both for operational use and for use in long-term ozone data records. In this paper, we will show results from our extensive analysis of the performance of the nadir mapper (NM) and nadir profiler (NP) sensors during the first year and a half of OMPS nadir operations. In most cases, we determined that both sensors meet or exceed their prelaunch specifications. Normalized radiance (radiance divided by irradiance) measurements have been determined to be well within their 2% specification for both sensors. In the case of stray light, the NM sensor is within its 2% specification for all but the shortest wavelengths, while the NP sensor is within its 2% specification for all but the longest wavelengths. Artifacts that negatively impacted the sensor calibration due to diffuser features were reduced to less than 1% through changes made in the solar calibration sequence. Preliminary analysis of the disagreement between measurements made by the NM and NP sensors in the region where their wavelengths overlap indicates that it is due to shifts in the shared dichroic filter after launch and that it can be corrected. In general, our analysis indicates that both the NM and NP sensors are performing well, that they are stable, and that any deviations from nominal performance can be well characterized and corrected.

  6. Postradiotherapy 2-Year Prostate-Specific Antigen Nadir as a Predictor of Long-Term Prostate Cancer Mortality

    SciTech Connect

    Zelefsky, Michael J.; Shi Weiji; Yamada, Yoshiya; Kollmeier, Marisa A.; Cox, Brett; Park, Jessica; Seshan, Venkatraman E.

    2009-12-01

    Purpose: To report the influence of posttreatment prostate-specific antigen (PSA) nadir response at 2 years after external beam radiotherapy (RT) on distant metastases (DM) and cause-specific mortality (CSM). Methods and Materials: Eight hundred forty-four patients with localized prostate cancer were treated with conformal RT. The median duration of follow-up was 9.1 years. A fixed landmark time point at 2 years was used to assess the influence of nadir PSA value as a time-dependent variable on long-term outcomes. Results: Multivariate analysis demonstrated that nadir PSA <=1.5 ng/mL at the landmark was an independent predictor of progression-free survival after adjusting for T stage, Gleason score, pre-RT PSA value, and RT dose (p = 0.03). The 5- and 10-year cumulative incidences of DM were 2.4% and 7.9%, respectively, in those with nadir PSA levels <=1.5 ng/mL at the 2-year landmark, and were 10.3% and 17.5%, respectively, in patients with higher nadir values. Multivariate analysis showed that the higher nadir PSA value at the 2-year landmark (p = 0.002), higher Gleason scores (p < 0.001), and increasing T stage (p = 0.03) were predictors of DM after adjusting for pre-RT PSA values and RT dose. Multivariate analysis also showed that higher Gleason scores (p = 0.002), and higher nadir PSA values at the 2-year landmark (p = 0.03) were risk factors associated with CSM after adjusting for T stage and pre-RT PSA value. Conclusions: Nadir PSA values of <=1.5 ng/mL at 2 years after RT for prostate cancer predict for long-term DM and CSM outcomes. Patients with higher absolute nadir levels at 2 years after treatment should be evaluated for the presence of nonresponding disease, and earlier salvage treatment interventions should be considered.

  7. An evaluation of the exposure in nadir observation of the JEM-EUSO mission

    NASA Astrophysics Data System (ADS)

    Adams, J. H.; Ahmad, S.; Albert, J.-N.; Allard, D.; Ambrosio, M.; Anchordoqui, L.; Anzalone, A.; Arai, Y.; Aramo, C.; Asano, K.; Ave, M.; Barrillon, P.; Batsch, T.; Bayer, J.; Belenguer, T.; Bellotti, R.; Berlind, A. A.; Bertaina, M.; Biermann, P. L.; Biktemerova, S.; Blaksley, C.; Błeçki, J.; Blin-Bondil, S.; Blümer, J.; Bobik, P.; Bogomilov, M.; Bonamente, M.; Briggs, M. S.; Briz, S.; Bruno, A.; Cafagna, F.; Campana, D.; Capdevielle, J.-N.; Caruso, R.; Casolino, M.; Cassardo, C.; Castellini, G.; Catalano, O.; Cellino, A.; Chikawa, M.; Christl, M. J.; Connaughton, V.; Cortés, J. F.; Crawford, H. J.; Cremonini, R.; Csorna, S.; D'Olivo, J. C.; Dagoret-Campagne, S.; de Castro, A. J.; De Donato, C.; de la Taille, C.; del Peral, L.; Dell'Oro, A.; De Pascale, M. P.; Di Martino, M.; Distratis, G.; Dupieux, M.; Ebersoldt, A.; Ebisuzaki, T.; Engel, R.; Falk, S.; Fang, K.; Fenu, F.; Fernández-Gómez, I.; Ferrarese, S.; Franceschi, A.; Fujimoto, J.; Galeotti, P.; Garipov, G.; Geary, J.; Giaccari, U. G.; Giraudo, G.; Gonchar, M.; González Alvarado, C.; Gorodetzky, P.; Guarino, F.; Guzmán, A.; Hachisu, Y.; Harlov, B.; Haungs, A.; Hernández Carretero, J.; Higashide, K.; Iguchi, T.; Ikeda, H.; Inoue, N.; Inoue, S.; Insolia, A.; Isgrò, F.; Itow, Y.; Joven, E.; Judd, E. G.; Jung, A.; Kajino, F.; Kajino, T.; Kaneko, I.; Karadzhov, Y.; Karczmarczyk, J.; Katahira, K.; Kawai, K.; Kawasaki, Y.; Keilhauer, B.; Khrenov, B. A.; Kim, Jeong-Sook; Kim, Soon-Wook; Kim, Sug-Whan; Kleifges, M.; Klimov, P. A.; Ko, S. H.; Kolev, D.; Kreykenbohm, I.; Kudela, K.; Kurihara, Y.; Kuznetsov, E.; La Rosa, G.; Lee, J.; Licandro, J.; Lim, H.; López, F.; Maccarone, M. C.; Mannheim, K.; Marcelli, L.; Marini, A.; Martin-Chassard, G.; Martinez, O.; Masciantonio, G.; Mase, K.; Matev, R.; Maurissen, A.; Medina-Tanco, G.; Mernik, T.; Miyamoto, H.; Miyazaki, Y.; Mizumoto, Y.; Modestino, G.; Monnier-Ragaigne, D.; Morales de los Ríos, J. A.; Mot, B.; Murakami, T.; Nagano, M.; Nagata, M.; Nagataki, S.; Nakamura, T.; Nam, J. W.; Nam, S.; Nam, K.; Napolitano, T.; Naumov, D.; Neronov, A.; Nomoto, K.; Ogawa, T.; Ohmori, H.; Olinto, A. V.; Orleański, P.; Osteria, G.; Pacheco, N.; Panasyuk, M. I.; Parizot, E.; Park, I. H.; Pastircak, B.; Patzak, T.; Paul, T.; Pennypacker, C.; Peter, T.; Picozza, P.; Pollini, A.; Prieto, H.; Reardon, P.; Reina, M.; Reyes, M.; Ricci, M.; Rodríguez, I.; Rodríguez Frías, M. D.; Ronga, F.; Rothkaehl, H.; Roudil, G.; Rusinov, I.; Rybczyński, M.; Sabau, M. D.; Sáez Cano, G.; Saito, A.; Sakaki, N.; Sakata, M.; Salazar, H.; Sánchez, S.; Santangelo, A.; Santiago Crúz, L.; Sanz Palomino, M.; Saprykin, O.; Sarazin, F.; Sato, H.; Sato, M.; Schanz, T.; Schieler, H.; Scotti, V.; Scuderi, M.; Segreto, A.; Selmane, S.; Semikoz, D.; Serra, M.; Sharakin, S.; Shibata, T.; Shimizu, H. M.; Shinozaki, K.; Shirahama, T.; Siemieniec-Oziebło, G.; Silva López, H. H.; Sledd, J.; Słomińska, K.; Sobey, A.; Sugiyama, T.; Supanitsky, D.; Suzuki, M.; Szabelska, B.; Szabelski, J.; Tajima, F.; Tajima, N.; Tajima, T.; Takahashi, Y.; Takami, H.; Takeda, M.; Takizawa, Y.; Tenzer, C.; Tibolla, O.; Tkachev, L.; Tomida, T.; Tone, N.; Trillaud, F.; Tsenov, R.; Tsuno, K.; Tymieniecka, T.; Uchihori, Y.; Vaduvescu, O.; Valdés-Galicia, J. F.; Vallania, P.; Valore, L.; Vankova, G.; Vigorito, C.; Villaseñor, L.; von Ballmoos, P.; Wada, S.; Watanabe, J.; Watanabe, S.; Watts, J.; Weber, M.; Weiler, T. J.; Wibig, T.; Wiencke, L.; Wille, M.; Wilms, J.; Włodarczyk, Z.; Yamamoto, T.; Yamamoto, Y.; Yang, J.; Yano, H.; Yashin, I. V.; Yonetoku, D.; Yoshida, K.; Yoshida, S.; Young, R.; Zamora, A.; Zuccaro Marchi, A.

    2013-04-01

    We evaluate the exposure during nadir observations with JEM-EUSO, the Extreme Universe Space Observatory, on-board the Japanese Experiment Module of the International Space Station. Designed as a mission to explore the extreme energy Universe from space, JEM-EUSO will monitor the Earth's nighttime atmosphere to record the ultraviolet light from tracks generated by extensive air showers initiated by ultra-high energy cosmic rays. In the present work, we discuss the particularities of space-based observation and we compute the annual exposure in nadir observation. The results are based on studies of the expected trigger aperture and observational duty cycle, as well as, on the investigations of the effects of clouds and different types of background light. We show that the annual exposure is about one order of magnitude higher than those of the presently operating ground-based observatories.

  8. Nadir CA-125 level as prognosis indicator of high-grade serous ovarian cancer

    PubMed Central

    2013-01-01

    Purpose The capacity of nadir CA-125 levels to predict the prognosis of epithelial ovarian cancer remains controversial. This study aimed to explore whether the nadir CA-125 serum levels could predict the durations of overall survival (OS) and progression free survival (PFS) in patients with high-grade serous ovarian cancer (HG-SOC) from the USA and PRC. Materials and methods A total of 616 HG-SOC patients from the MD Anderson Cancer Center (MDACC, USA) between 1990 and 2011 were retrospectively analyzed. The results of 262 cases from the Jiangsu Institute of Cancer Research (JICR, PRC) between 1992 and 2011 were used to validate the MDACC data. The CA-125 immunohistochemistry assay was performed on 280 tissue specimens. The Cox proportional hazards model and the log-rank test were used to assess the associations between the clinicopathological characteristics and duration of survival. Results The nadir CA-125 level was an independent predictor of OS and PFS (p < 0.01 for both) in the MDACC patients. Lower nadir CA-125 levels (≤10 U/mL) were associated with longer OS and PFS (median: 61.2 and 16.8 months with 95% CI: 52.0–72.4 and 14.0–19.6 months, respectively) than their counterparts with shorter OS and PFS (median: 49.2 and 10.5 months with 95% CI: 41.7–56.7 and 6.9–14.1 months, respectively). The nadir CA-125 levels in JICR patients were similarly independent when predicting the OS and PFS (p < 0.01 for both). Nadir CA-125 levels less than or equal to 10 U/mL were associated with longer OS and PFS (median: 59.9 and 15.5 months with 95% CI: 49.7–70.1 and 10.6–20.4 months, respectively), as compared with those more than 10 U/mL (median: 42.0 and 9.0 months with 95% CI: 34.4–49.7 and 6.6–11.2 months, respectively). Baseline serum CA-125 levels, but not the CA-125 expression in tissues, were associated with the OS and PFS of HG-SOC patients in the MDACC and JICR groups. However, these values were not independent. Nadir CA-125

  9. Tropospheric ozone retrieval by using SCIAMACHY Limb-Nadir-Matching method

    NASA Astrophysics Data System (ADS)

    Jia, Jia; Ladstätter-Weissenmayer, Annette; Ebojie, Felix; Rozanov, Alexei; Burrows, John

    2014-05-01

    Tropospheric ozone is photochemically produced during pollution events and transported from the stratosphere towards the troposphere. It is the third most important green house gases and the main component of summer smog. Global covered satellite measurements are well suitable to investigate sources, sinks, and transport mechanisms of tropospheric ozone in a global view, and to study a characteristic behaviour of the tropospheric ozone in regions. However, the usage of satellite data is associated to a large uncertainty as 90% ozone is located in the stratosphere and only the remaining part of 10% can be observed in the troposphere. The limb-nadir matching (LNM) technique is one of the methods suitable to retrieve tropospheric ozone distributions from space borne observations of the scattered solar light in the UV-visible spectral range. In this study we apply the LNM approach to alternating limb and nadir measurements performed by the SCIAMACHY instrument. A precise tropopause height is used to subtract the stratospheric ozone from the total ozone amount for each matching point. The focus of this work is to reduce the uncertainty of the resulting tropospheric ozone distributions by analysing possible error sources, refining both limb and nadir retrievals and the matching technique.

  10. Crown depth as a result of evolutionary games: decreasing solar angle should lead to shallower, not deeper crowns.

    PubMed

    Vermeulen, Peter Johannes

    2014-06-01

    There is a general notion in the literature that, with increasing latitude, trees have deeper crowns as a result of a lower solar elevation angle. However, these predictions are based on models that did not include the effects of competition for light between individuals. Here, I argue that there should be selection for trees to increase the height of the crown base, as this decreases shading by neighbouring trees, leading to an evolutionarily stable strategy (ESS). Because the level of between-tree shading increases with decreasing solar angle, the predicted ESS will shift to higher crown base height. This argument is supported by a simulation model to check for the effects of crown shape and the change of light intensity that occurs with changing solar angle on model outcomes. So, the lower solar angle at higher latitudes would tend to select for shallower, and not deeper, crowns. This casts doubt on the common belief that a decreasing solar angle increases crown depth. More importantly, it shows that different assumptions about what should be optimized can lead to different predictions, not just for absolute trait values, but for the direction of selection itself. PMID:24548219

  11. New Archiving Distributed InfrastructuRe (NADIR): Status and Evolution

    NASA Astrophysics Data System (ADS)

    De Marco, M.; Knapic, C.; Smareglia, R.

    2015-09-01

    The New Archiving Distributed InfrastructuRe (NADIR) has been developed at INAF-OATs IA2 (Italian National Institute for Astrophysics - Astronomical Observatory of Trieste, Italian center of Astronomical Archives), as an evolution of the previous archiving and distribution system, used on several telescopes (LBT, TNG, Asiago, etc.) to improve performance, efficiency and reliability. At the present, NADIR system is running on LBT telescope and Vespa (Italian telescopes network for outreach) Ramella et al. (2014), and will be used on TNG, Asiago and IRA (Istituto Radio Astronomia) archives of Medicina, Noto and SRT radio telescopes Zanichelli et al. (2014) as the data models for radio data will be ready. This paper will discuss the progress status, the architectural choices and the solutions adopted, during the development and the commissioning phase of the project. A special attention will be given to the LBT case, due to some critical aspect of data flow and policies and standards compliance, adopted by the LBT organization.

  12. Thermal infrared nadir observations of 24 atmospheric gases

    NASA Astrophysics Data System (ADS)

    Clarisse, Lieven; R'Honi, Yasmina; Coheur, Pierre-François; Hurtmans, Daniel; Clerbaux, Cathy

    2011-05-01

    Thermal infrared nadir sounders are ideal for observing total columns or vertical profiles of atmospheric gases such as water, carbon dioxide and ozone. High resolution sounders with a spectral resolution below 5 cm-1 can distinguish fine spectral features of trace gases. Forty years after the launch of the first hyperspectral sounder IRIS, we have now several state of the art instruments in orbit, with improved instrumental specifications. In this letter we give an overview of the trace gases which have been observed by infrared nadir sounders, focusing on new observations of the Infrared Atmospheric Sounding Interferometer (IASI). We present typical observations of 14 rare reactive trace gas species. Several species are reported here for the first time in nadir view, including nitrous acid, furan, acetylene, propylene, acetic acid, formaldehyde and hydrogen cyanide, observations which were made in a pyrocumulus cloud from the Australian bush fires of February 2009. Being able to observe this large number of reactive trace gases will likely improve our knowledge of source emissions and their impact on the environment and climate.

  13. Measurement of nadir and near-nadir 94-GHz brightness temperatures of several tactical-scene clutter types

    NASA Astrophysics Data System (ADS)

    Wikner, David A.; Pizzillo, Thomas J.

    1999-07-01

    The authors present 94-GHz radiometric brightness temperatures of various clutter materials at nadir. The clutter materials measured include field vegetation, asphalt pavement, and an asphalt shingle roof and data is presented for each clutter type. We also report measurements that quantify the effect of water on the brightness temperature of metal. These measurements were made by adding calibrated quantities of water to a metal plate while recording the plate's millimeter-wave brightness temperature. Off-nadir data out to 45 deg is also presented for the field vegetation and asphalt pavement. Using a simple rough scattering model for the materials, we made estimates of the emissivity of the field vegetation and asphalt. The emissivity of the roof was determined by measuring its brightness temperature as it was heated.

  14. NADIR: Monitoring, Error Handling, and Logging with Tango

    NASA Astrophysics Data System (ADS)

    De Marco, M.; Knapic, C.; Smareglia, R.

    2014-05-01

    The ingest and transport of a large amount of astronomical data, in geographically distributed archives, imply some challenging issues, like remote control and configuration, monitoring and logging anomalous conditions, fault tolerance and error handling. Based on this considerations and on our experience in data management, we started development of a New Archiving Distributed InfrastructuRe (NADIR), using Tango (Team 2013; S. Gara 2012), a well known distributed control system (DCSs) within scientific environments, taking advantage of its key features, like reliability, scalability, logging and alarm system, consolidated pattern and template, to solve this complexity. In this paper we discuss about design choices and technical aspects around this project.

  15. ICU Blood Pressure Variability May Predict Nadir of Respiratory Depression After Coronary Artery Bypass Surgery

    PubMed Central

    Costa, Anne S. M.; Costa, Paulo H. M.; de Lima, Carlos E. B.; Pádua, Luiz E. M.; Campos, Luciana A.; Baltatu, Ovidiu C.

    2016-01-01

    Objectives: Surgical stress induces alterations on sympathovagal balance that can be determined through assessment of blood pressure variability. Coronary artery bypass graft surgery (CABG) is associated with postoperative respiratory depression. In this study we aimed at investigating ICU blood pressure variability and other perioperative parameters that could predict the nadir of postoperative respiratory function impairment. Methods: This prospective observational study evaluated 44 coronary artery disease patients subjected to coronary artery bypass surgery (CABG) with cardiopulmonary bypass (CPB). At the ICU, mean arterial pressure (MAP) was monitored every 30 min for 3 days. MAP variability was evaluated through: standard deviation (SD), coefficient of variation (CV), variation independent of mean (VIM), and average successive variability (ASV). Respiratory function was assessed through maximal inspiratory (MIP) and expiratory (MEP) pressures and peak expiratory flow (PEF) determined 1 day before surgery and on the postoperative days 3rd to 7th. Intraoperative parameters (volume of cardioplegia, CPB duration, aortic cross-clamp time, number of grafts) were also monitored. Results: Since, we aimed at studying patients without confounding effects of postoperative complications on respiratory function, we had enrolled a cohort of low risk EuroSCORE (European System for Cardiac Operative Risk Evaluation) with < 2. Respiratory parameters MIP, MEP, and PEF were significantly depressed for 4–5 days postoperatively. Of all MAP variability parameters, the ASV had a significant good positive Spearman correlation (rho coefficients ranging from 0.45 to 0.65, p < 0.01) with the 3-day nadir of PEF after cardiac surgery. Also, CV and VIM of MAP were significantly associated with nadir days of MEP and PEF. None of the intraoperative parameters had any correlation with the postoperative respiratory depression. Conclusions: Variability parameters ASV, CV, and VIM of the MAP

  16. Diode laser transscleral cyclophotocoagulation followed by phacotrabeculectomy on medically unresponsive acute primary angle closure eyes: the long-term result

    PubMed Central

    2014-01-01

    Background To explore the intraocular pressure-lowering effect and complications of diode laser transscleral cyclophotocoagulation (DLTSC) followed by phacotrabeculectomy on medically unresponsive acute primary angle closure eyes. Methods Nine eyes of nine medically unresponsive acute primary angle closure patients were enrolled. All the patients underwent cyclophotocoagulation followed by phacotrabeculectomy to control the prolonged acute attack. Data were recorded prospectively and then analyzed retrospectively. The reduction in intraocular pressure, improvement of vision and the complications were evaluated. Results After DLTSC, the IOP of all the patients were reduced, but all were above 21 mmHg under topical anti-glaucoma medications. After phacotrabeculectomy, the IOP of all the patients was decreased. At the final visit, the vision of all the patients was improved and the IOP of all the patients was below 21 mmHg without anti-glaucoma medications. There were no complications during the DLTSC and phacotrabeculectomy. Uveitis was the common complications after the both procedures, which were resolved by medication treatment. Conclusion Diode laser transscleral cyclophotocoagulation followed by phacotrabeculectomy is an alternative procedure to control the intraocular pressure of medically unresponsive acute primary angle closure eyes with few complications. PMID:24606842

  17. Understanding angular effects in VHR imagery and their significance for urban land-cover model portability: A study of two multi-angle in-track image sequences

    NASA Astrophysics Data System (ADS)

    Matasci, Giona; Longbotham, Nathan; Pacifici, Fabio; Kanevski, Mikhail; Tuia, Devis

    2015-09-01

    This paper investigates the angular effects causing spectral distortions in multi-angle remote sensing imagery. We study two WorldView-2 multispectral in-track sequences acquired over the cities of Atlanta, USA, and Rio de Janeiro, Brazil, consisting of 13 and 20 co-located images, respectively. The sequences possess off-nadir acquisition angles up to 47.5° and bear markedly different sun-satellite configurations with respect to each other. Both scenes comprise classic urban structures such as buildings of different size, road networks, and parks. First, we quantify the degree of distortion affecting the sequences by means of a non-linear measure of distance between probability distributions, the Maximum Mean Discrepancy. Second, we assess the ability of a classification model trained on an image acquired at a certain view angle to predict the land-cover of all the other images in the sequence. The portability across the sequence is investigated for supervised classifiers of different nature by analyzing the evolution of the classification accuracy with respect to the off-nadir look angle. For both datasets, the effectiveness of physically- and statistically-based normalization methods in obtaining angle-invariant data spaces is compared and synergies are discussed. The empirical results indicate that, after a suitable normalization (histogram matching, atmospheric compensation), the loss in classification accuracy when using a model trained on the near-nadir image to classify the most off-nadir acquisitions can be reduced to as little as 0.06 (Atlanta) or 0.03 (Rio de Janeiro) Kappa points when using a SVM classifier.

  18. Recent Results from the Wide Angle Search for Planets (WASP) Prototype

    NASA Astrophysics Data System (ADS)

    Kane, S. R.; Horne, K.; Lister, T.; Collier Cameron, A.; Street, R. A.; Pollacco, D. L.; James, D.; Tsapras, Y.

    2004-12-01

    WASP0 is a prototype for what is intended to become a collection of WASPs whose primary aim is to detect transiting extra-solar planets across the face of their parent star. We present some recent results from the WASP0 camera, including observations of the known transiting planet around HD 209458. The current status of the next generation camera (SuperWASP) located on La Palma is briefly outlined.

  19. A comparative analysis of UV nadir-backscatter and infrared limb-emission ozone data assimilation

    NASA Astrophysics Data System (ADS)

    Dragani, Rossana

    2016-07-01

    This paper presents a comparative assessment of ultraviolet nadir-backscatter and infrared limb-emission ozone profile assimilation. The Meteorological Operational Satellite A (MetOp-A) Global Ozone Monitoring Experiment 2 (GOME-2) nadir and the ENVISAT Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) limb profiles, generated by the ozone consortium of the European Space Agency Climate Change Initiative (ESA O3-CCI), were individually added to a reference set of ozone observations and assimilated in the European Centre for Medium-Range Weather Forecasts (ECMWF) data assimilation system (DAS). The two sets of resulting analyses were compared with that from a control experiment, only constrained by the reference dataset, and independent, unassimilated observations. Comparisons with independent observations show that both datasets improve the stratospheric ozone distribution. The changes inferred by the limb-based observations are more localized and, in places, more important than those implied by the nadir profiles, albeit they have a much lower number of observations. A small degradation (up to 0.25 mg kg-1 for GOME-2 and 0.5 mg kg-1 for MIPAS in the mass mixing ratio) is found in the tropics between 20 and 30 hPa. In the lowermost troposphere below its vertical coverage, the limb data are found to be able to modify the ozone distribution with changes as large as 60 %. Comparisons of the ozone analyses with sonde data show that at those levels the assimilation of GOME-2 leads to about 1 Dobson Unit (DU) smaller root mean square error (RMSE) than that of MIPAS. However, the assimilation of MIPAS can still improve the quality of the ozone analyses and - with a reduction in the RMSE of up to about 2 DU - outperform the control experiment thanks to its synergistic assimilation with total-column ozone data within the DAS. High vertical resolution ozone profile observations are essential to accurately monitor and forecast ozone concentrations in a DAS

  20. Computer communications through telecommunications satellite systems - The NADIR project

    NASA Astrophysics Data System (ADS)

    Grange, J.-L.

    Current developments in satellite digital communication in Europe are surveyed, and the status of the French NADIR project begun in 1980 is reported. The geographic coverage, transmission rates, propagation delays, broadcasting and multidestination channels, and error rates characteristic of present satellite systems are discussed, and the specific performance parameters of the Telecom-1 system, comprising three geosynchronous satellites (one operational and two backup) with six 25-Mbit/sec, 12-14-GHz digital transponders and one 4-6 GHz analog port (for telephone and TV services) each, are examined. Telecom-1 will operate in a TDMA-AD mode with coverage of up to 320 earth stations in Central and Western Europe, transmission rates of 2.4-2000 kbit/sec, and error rates less than 10 to the -6th during 99 percent of the time. New applications foreseen include remote processing, distributed databases, computer teleconferencing, and electronic mail systems; new basic tools such as bulk-transfer and transaction-transfer protocols and database-management systems will be required. These tools are under development and testing (using the ANIS Telecom-1 simulator) by NADIR.

  1. Recent Results from the Wide Angle Search for Planets (WASP) Prototype

    NASA Astrophysics Data System (ADS)

    Kane, S. R.; Horne, K.; Street, R. A.; Pollaco, D. L.; James, D.; Tsapras, Y.; Collier Cameron, A.

    WASP0 is a prototype for what is intended to become a collection of WASPs whose primary aim is to detect transiting extrasolar planets across the face of their parent star. The WASP0 instrument is a wide-field (9-degree) 6.3 cm aperture F/2.8 Apogee 10 CCD camera (2Kx2K chip, 16-arcsec pixels). The camera is mounted piggy-back on a commercial 10-inch Meade telescope. We present some recent results from the WASP camera, including observations from La Palma of the known transiting planet around HD 209458 and preliminary analysis of other stars located in the same field. We also outline further problems which restrict the ability to achieve photon limited precision with a wide-field commercial CCD.

  2. The impact of ozone field horizontal inhomogeneities on nadir-viewing orbital backscatter UV measurements

    NASA Technical Reports Server (NTRS)

    Mueller, Martin D.; Poli, Paul; Joiner, Joanna

    2005-01-01

    Radiative transfer calculations for nadir-viewing satellites normally assume the atmosphere to be horizontally homogeneous. Yet it has been shown recently that horizontal gradients can lead to significant errors in satellite infrared and microwave soundings. We extend the methodology to backscatter ultra-violet observations of ozone, and present a first estimate of the effect s magnitude. The Solar Backscatter Ultra-Violet/2 (SBUV/2) instrument, a pure nadir sounder, serves as our test bed. Our results indicate that in a vast majority of cases the abovementioned errors can be neglected. However, occurrence of higher errors, particularly at wavelengths longer than 300 nm, coincides with some of the most interesting atmospheric phenomena like tropopause folds and the South polar ozone hole. This leads to a seasonal variation of the magnitude of the effect. Due to the mostly zonal geometry of the ozone distribution, there is also the possibility that biases may be introduced, which is particularly critical if the data are to be assimilated or used to determine trends. The results presented are tested for robustness using different model atmospheres. The influence of horizontal inhomogeneities will be even more pronounced for cross-track sounders and limb viewers, and easier to detect once higher resolution atmospheric models are available. This will be investigated in future studies.

  3. Precipitation measurement using SIR-C: A feasibility study. Investigation at nadir

    NASA Technical Reports Server (NTRS)

    Ahamad, Atiq; Moore, Richard K.

    1993-01-01

    The most significant limitation of the imaging SAR in rain measurements is the ground return coupled to the rain cell. Here we report a study of the possibility of using the X-SAR and the C-band channel of SIR-C for rain measurement. Earlier signal-to-clutter calculations rule out the use of X-SAR at steeper off-vertical angles of incidence (i.e., 20 less than theta less than 50). Only rain rates greater than 30 mm/hr at angles of incidence greater than 60 degrees showed good signal-to-clutter ratio (SCR). This study involved calculations at vertical incidence. There is adequate signal-to-noise ratio (SNR) at vertical incidence, but the presence of high-range side-lobe levels leads to small SCR for measurement over oceans at both X and C bands. For larger rain thickness (greater than two km), the SCR gets better and smaller rain rates (greater than 10 mm/hr) can be measured. However, rain measurements over forests seem to be feasible at nadir even for smaller rain thickness (less than two km). We conclude that X band may be usable over the forest at vertical incidence to measure rain rates greater than five mm/hr even for shallow rain thickness and over ocean for large rain thickness.

  4. Constraining the physical properties of Titan's empty lake basins using nadir and off-nadir Cassini RADAR backscatter

    NASA Astrophysics Data System (ADS)

    Michaelides, R. J.; Hayes, A. G.; Mastrogiuseppe, M.; Zebker, H. A.; Farr, T. G.; Malaska, M. J.; Poggiali, V.; Mullen, J. P.

    2016-05-01

    We use repeat synthetic aperture radar (SAR) observations and complementary altimetry passes acquired by the Cassini spacecraft to study the scattering properties of Titan's empty lake basins. The best-fit coefficients from fitting SAR data to a quasi-specular plus diffuse backscatter model suggest that the bright basin floors have a higher dielectric constant, but similar facet-scale rms surface facet slopes, to surrounding terrain. Waveform analysis of altimetry returns reveals that nadir backscatter returns from basin floors are greater than nadir backscatter returns from basin surroundings and have narrower pulse widths. This suggests that floor deposits are structurally distinct from their surroundings, consistent with the interpretation that some of these basins may be filled with evaporitic and/or sedimentary deposits. Basin floor deposits also express a larger diffuse component to their backscatter, which is likely due to variations in subsurface structure or an increase in roughness at the wavelength scale (Hayes, A.G. et al. [2008]. Geophys. Res. Lett. 35, 9). We generate a high-resolution altimetry radargram of the T30 altimetry pass over an empty lake basin, with which we place geometric constraints on the basin's slopes, rim heights, and depth. Finally, the importance of these backscatter observations and geometric measurements for basin formation mechanisms is briefly discussed.

  5. Results of multiband (L, S, Ku band) propagation measurements and model for high elevation angle land mobile satellite channel

    NASA Technical Reports Server (NTRS)

    Parks, M. A. N.; Butt, G.; Evans, Barry G.; Richharia, M.

    1993-01-01

    Signal propagation in the land mobile satellite (LMS) service is an important consideration due to its critical impact on the overall economic and commercial viability of the system. At frequencies allocated for LMS systems, shadowing of the line-of-sight (LOS) signal as well as multipath propagation phenomena can severely impair the link availability. In particular, as most of the studies have shown, the shadowing of LOS signal causes long and deep fades in a variety of mobile environments due to the inherent nature of the channel between the satellite and a mobile. Roadside obstacles, such as buildings, trees, utility poles etc., in the immediate vicinity of a mobile and the surrounding terrain are major sources of signal shadowing in LMS links. Therefore, a proper knowledge of link degradation is essential for cost-effective planning of a satellite based mobile communication system. The results of a propagation campaign undertaken to characterize the fading nature of LMS channel at high elevation angles is presented. It was envisaged that one of the most important physical variables contributing to the amount of LOS signal shadowing is the elevation angle of the satellite. At higher elevation angles to the satellite, less obstructions in the direct satellite-to-mobile path would therefore amount to statistically better link availability. Narrowband channel measurements were carried out at three RF frequencies corresponding to L (1.3 GHz), S (2.32/2.45 GHz), and Ku (10.4 GHz) bands. The campaign itself was divided into two phases to observe the effects of seasonal variation of foliage on the roadside trees. Phase measurements were carried out in September 1991 and in April 1992. Some important aspects from the statistical analysis of the propagation data are presented.

  6. Results of multiband (L, S, Ku band) propagation measurements and model for high elevation angle land mobile satellite channel

    NASA Astrophysics Data System (ADS)

    Parks, M. A. N.; Butt, G.; Evans, Barry G.; Richharia, M.

    1993-08-01

    Signal propagation in the land mobile satellite (LMS) service is an important consideration due to its critical impact on the overall economic and commercial viability of the system. At frequencies allocated for LMS systems, shadowing of the line-of-sight (LOS) signal as well as multipath propagation phenomena can severely impair the link availability. In particular, as most of the studies have shown, the shadowing of LOS signal causes long and deep fades in a variety of mobile environments due to the inherent nature of the channel between the satellite and a mobile. Roadside obstacles, such as buildings, trees, utility poles etc., in the immediate vicinity of a mobile and the surrounding terrain are major sources of signal shadowing in LMS links. Therefore, a proper knowledge of link degradation is essential for cost-effective planning of a satellite based mobile communication system. The results of a propagation campaign undertaken to characterize the fading nature of LMS channel at high elevation angles is presented. It was envisaged that one of the most important physical variables contributing to the amount of LOS signal shadowing is the elevation angle of the satellite. At higher elevation angles to the satellite, less obstructions in the direct satellite-to-mobile path would therefore amount to statistically better link availability. Narrowband channel measurements were carried out at three RF frequencies corresponding to L (1.3 GHz), S (2.32/2.45 GHz), and Ku (10.4 GHz) bands. The campaign itself was divided into two phases to observe the effects of seasonal variation of foliage on the roadside trees. Phase measurements were carried out in September 1991 and in April 1992. Some important aspects from the statistical analysis of the propagation data are presented.

  7. NPP VIIRS and Aqua MODIS RSB comparison using observations from simultaneous nadir overpasses (SNO)

    NASA Astrophysics Data System (ADS)

    Wu, Aisheng; Xiong, Xiaoxiong

    2012-09-01

    Suomi NPP (National Polar-orbiting Partnership) satellite (http://npp.gsfc.nasa.gov/viirs.html) began to daily collect global data following its successful launch on October 28, 2011. The Visible Infrared Imaging Radiometer Suite (VIIRS) is a key NPP sensor. Similar to the design of the OLS, SeaWiFS and MODIS instruments, VIIRS has on-board calibration components including a solar diffuser (SD) and a solar diffuser stability monitor (SDSM) for the reflective solar bands (RSB), a V-groove blackbody for the thermal emissive bands (TEB), and a space view (SV) port for background subtraction. Immediately after the VIIRS nadir door's opening on November 21, 2011, anomalously large degradation in the SD response was identified in the near-IR wavelength region, which was unexpected as decreases in the SD reflectance usually occur gradually in the blue (~0.4 μm) wavelength region based on past experience. In this study, we use a well-calibrated Aqua MODIS as reference to track and evaluate VIIRS RSB stability and performance. Reflectances observed by both sensors from simultaneous nadir overpasses (SNO) are used to determine VIIRS to MODIS reflectance ratios for their spectral matching bands. Results of this study provide an immediate post-launch assessment, independent validation of the anomalous degradation observed in SD measurements at near-IR wavelengths and initial analysis of calibration stability and consistency.

  8. NPP VIIRS and Aqua MODIS RSB Comparison Using Observations from Simultaneous Nadir Overpasses (SNO)

    NASA Technical Reports Server (NTRS)

    Xiong, X.; Wu, A.

    2012-01-01

    Suomi NPP (National Polar-orbiting Partnership) satellite (http://npp.gsfc.nasa.gov/viirs.html) began to daily collect global data following its successful launch on October 28, 2011. The Visible Infrared Imaging Radiometer Suite (VIIRS) is a key NPP sensor. Similar to the design of the OLS, SeaWiFS and MODIS instruments, VIIRS has on-board calibration components including a solar diffuser (SD) and a solar diffuser stability monitor (SDSM) for the reflective solar bands (RSB), a V-groove blackbody for the thermal emissive bands (TEB), and a space view (SV) port for background subtraction. Immediately after the VIIRS nadir door s opening on November 21, 2011, anomalously large degradation in the SD response was identified in the near-IR wavelength region, which was unexpected as decreases in the SD reflectance usually occur gradually in the blue (0.4 m) wavelength region based on past experience. In this study, we use a well-calibrated Aqua MODIS as reference to track and evaluate VIIRS RSB stability and performance. Reflectances observed by both sensors from simultaneous nadir overpasses (SNO) are used to determine VIIRS to MODIS reflectance ratios for their spectral matching bands. Results of this study provide an immediate post-launch assessment, independent validation of the anomalous degradation observed in SD measurements at near-IR wavelengths and initial analysis of calibration stability and consistency.

  9. [Surgical results of dissection of the superficial temporal artery in patients with preglaucoma and initial open-angle glaucoma].

    PubMed

    Shilkin, G A; Iartseva, N S; Mironova, E M; Oreshkina, R M; Mikhaĭlova, G D

    1989-01-01

    Results of superficial temporal artery dissection performed in 42 patients (44 eyes) with preglaucoma and initial open-angle glaucoma have shown no impairement of visual field, visual acuity, optic disc in the period from 0.5 to 1.5 years after it. The increased linear rate of bloodflow after the operation remained stable in 17 eyes of patients with preglaucoma and in 14 eyes of patients with glaucoma. Intraocular pressure became normalized in 20 and 19 eyes as well as intraocular fluid outflow in 14 and 13 eyes, respectively. In both groups there was a tendency to normalization of retinal functions and hydrodynamics of the eye. Thus, the operation produces improvement of regional bloodflow, tonographic and electrophysiologic indices. Its usage is considered to be reasonable, but, when determining indications to it, an individual approach is necessary. PMID:2755669

  10. Capturing tropospheric ozone time variability : a study using TES Nadir Retrievals

    NASA Technical Reports Server (NTRS)

    Bowman, Kevin; Steck, T.; Worden, H.; Worden, J.; Clough, S.; Rodgers, C.

    2001-01-01

    We perform nadir retrievals of ozone using simulated radiances from ozone-sondes over Bermuda from April 14 to May 25, 1993. Using a novel two-step retrieval strategy, we characterize the sensitivity of TES nadir retrievals to time variations of ozone. 02000 Optical Society of America.

  11. TES/Aura L2 Water Vapor (H2O) Nadir (TL2H2ON)

    Atmospheric Science Data Center

    2015-01-30

    TES/Aura L2 Water Vapor (H2O) Nadir (TL2H2ON) News:  TES News ... Title:  TES Discipline:  Tropospheric Chemistry Level:  L2 Instrument:  TES/Aura L2 Water Vapor Spatial Coverage:  5.3 x 8.5 km nadir ...

  12. TES/Aura L2 Water Vapor (H2O) Nadir (TL2H2ONS)

    Atmospheric Science Data Center

    2015-01-30

    TES/Aura L2 Water Vapor (H2O) Nadir (TL2H2ONS) News:  TES News ... Title:  TES Discipline:  Tropospheric Chemistry Level:  L2 Platform:  TES/Aura L2 Water Vapor Spatial Coverage:  5.3 8.5 km nadir ...

  13. TES/Aura L2 Carbon Monoxide (CO) Lite Nadir (TL2COLN)

    Atmospheric Science Data Center

    2015-06-16

    TES/Aura L2 Carbon Monoxide (CO) Lite Nadir (TL2COLN) News:  TES News ... Level:  L2 Instrument:  TES/Aura L2 Carbon Monoxide Spatial Coverage:  5.3 km nadir ... OPeNDAP Access:  OPeNDAP Parameters:  Carbon Monoxide Order Data:  Reverb:   Order Data ...

  14. TES/Aura L2 Carbon Dioxide (CO2) Nadir (TL2CO2N)

    Atmospheric Science Data Center

    2015-01-30

    TES/Aura L2 Carbon Dioxide (CO2) Nadir (TL2CO2N) News:  TES News ... L2 Platform:  TES/Aura L2 Carbon Dioxide Spatial Coverage:  5.2 x 8.5 km nadir ... Subset Data: TES Order Tool Parameters:  Carbon Dioxide Order Data:  Reverb:   Order Data ...

  15. TES/Aura L2 Carbon Dioxide (CO2) Nadir (TL2CO2NS)

    Atmospheric Science Data Center

    2015-01-30

    TES/Aura L2 Carbon Dioxide (CO2) Nadir (TL2CO2NS) News:  TES News ... L2 Platform:  TES/Aura L2 Carbon Dioxide Spatial Coverage:  5.3 x 8.5 km nadir ... Subset Data: TES Order Tool Parameters:  Carbon Dioxide Order Data:  Reverb:   Order Data ...

  16. Characterization of Global Near-Nadir Backscatter for Remote Sensing Radar Design

    NASA Technical Reports Server (NTRS)

    Spencer, Michael W.; Long, David G.

    2000-01-01

    In order to evaluate side-lobe contamination from the near-nadir region for Ku-Band radars, a statistical characterization of global near-nadir backscatter is constructed. This characterization is performed for a variety of surface types using data from TRMM, Seasat, and Topex. An assessment of the relative calibration accuracy of these sensors is also presented.

  17. Characterization of Global Near-Nadir Backscatter for Remote Sensing Radar Design

    NASA Technical Reports Server (NTRS)

    Spencer, Michael W.; Long, David G.

    2000-01-01

    In order to evaluate side-lobe contamination from the near-nadir region for Ku-Band radars, a statistical characterization of global near-nadir backscatter is constructed. This characterization is performed for a variety of surface types using data from TRMM, Seasat, and Topex. An assessment of the relative calibration accuracy of them sensors is also presented.

  18. TES/Aura L2 Ammonia (NH3) Nadir (TL2NH3NS)

    Atmospheric Science Data Center

    2015-01-30

    TES/Aura L2 Ammonia (NH3) Nadir (TL2NH3NS) News:  TES News ... Level:  L2 Platform:  TES/Aura L2 Ammonia Spatial Coverage:  5.3 x 8.5 km nadir ... Data: TES Order Tool Parameters:  Ammonia Order Data:  Reverb:   Order Data ...

  19. TES/Aura L2 Ammonia (NH3) Nadir (TL2NH3N)

    Atmospheric Science Data Center

    2015-01-30

    TES/Aura L2 Ammonia (NH3) Nadir (TL2NH3N) News:  TES News ... Level:  L2 Instrument:  TES/Aura L2 Ammonia Spatial Coverage:  5.3 x 8.5 km nadir ... Data: TES Order Tool Parameters:  Ammonia Order Data:  Reverb:   Order Data ...

  20. TES/Aura L2 Formic Acid (FOR) Nadir (TL2FORN)

    Atmospheric Science Data Center

    2015-02-04

    TES/Aura L2 Formic Acid (FOR) Nadir (TL2FORN) News:  TES News Join ... L2 Platform:  TES/Aura L2 Formic Acid Spatial Coverage:  5.3 x 8.5 km nadir Spatial ... Access:  OPeNDAP Parameters:  Formic Acid Volume Mixing Ratio Precision Vertical Resolution Order ...

  1. TES/Aura L2 Formic Acid (FOR) Lite Nadir (TL2FORLN)

    Atmospheric Science Data Center

    2015-06-16

    TES/Aura L2 Formic Acid (FOR) Lite Nadir (TL2FORLN) News:  TES News ... L2 Instrument:  TES/Aura L2 Formic Acid Spatial Coverage:  5.3 km nadir Spatial ... Access:  OPeNDAP Parameters:  Formic Acid Volume Mixing Ratio Vertical Resolution Precision Order ...

  2. TES/Aura L2 Formic Acid (FOR) Nadir (TL2FORNS)

    Atmospheric Science Data Center

    2015-02-04

    TES/Aura L2 Formic Acid (FOR) Nadir (TL2FORNS) News:  TES News Join ... L2 Platform:  TES/Aura L2 Formic Acid Spatial Coverage:  5.3 x 8.5 km nadir Spatial ... Access:  OPeNDAP Parameters:  Formic Acid Volume Mixing Ratio Precision Vertical Resolution Order ...

  3. Tropospheric Ozone Near-Nadir-Viewing IR Spectral Sensitivity and Ozone Measurements from NAST-I

    NASA Technical Reports Server (NTRS)

    Zhou, Daniel K.; Smith, William L.; Larar, Allen M.

    2001-01-01

    Infrared ozone spectra from near nadir observations have provided atmospheric ozone information from the sensor to the Earth's surface. Simulations of the NPOESS Airborne Sounder Testbed-Interferometer (NAST-I) from the NASA ER-2 aircraft (approximately 20 km altitude) with a spectral resolution of 0.25/cm were used for sensitivity analysis. The spectral sensitivity of ozone retrievals to uncertainties in atmospheric temperature and water vapor is assessed in order to understand the relationship between the IR emissions and the atmospheric state. In addition, ozone spectral radiance sensitivity to its ozone layer densities and radiance weighting functions reveals the limit of the ozone profile retrieval accuracy from NAST-I measurements. Statistical retrievals of ozone with temperature and moisture retrievals from NAST-I spectra have been investigated and the preliminary results from NAST-I field campaigns are presented.

  4. The Grenville Front Tectonic Zone: Results from the 1986 Great Lakes Onshore Seismic Wide-Angle Reflection and Refraction Experiment

    NASA Astrophysics Data System (ADS)

    Epili, Duryodhan; Mereu, Robert F.

    1991-09-01

    The Grenville Front, which marks the orogenic boundary between the Archean Superior Structural Province and the much younger Grenville Province to the southeast, is one of the major tectonic features of the Canadian Shield. Within Canada, it is approximately 1900 km in length extending from the north shore of Lake Huron across Ontario and Quebec to Labrador. In 1986, a major coincident onship near-vertical reflection and onshore wide-angle reflection/refraction experiment (GLIMPCE-Great Lakes International Multidisciplinary Program on Crustal Evolution) was conducted along a series of lines across the Great lakes. One of the lines, line J, ran across Georgian Bay and Lake Huron for a distance of 350 km and crossed the Grenville Front Tectonic Zone (GFTZ). The seismic signals from the air gun array source were well recorded by the onshore stations up to distances of 250 km with a seismic trace spacing of 50-62.5 m. The GFTZ had a profound effect on the nature of the reflector patterns observed on the onshore seismic sections. Data recorded by the stations on the east end of the line indicate that the crustal P phases are very complex and form a "shinglelike" pattern of reflected waves. Data recorded by stations at the center and at the western end of the line show that the Pg phases are normal and lack the shinglelike appearance. This character of arrivals was also observed on the corresponding S wave sections. A combined P and S wave forward modeling analysis shows that the GFTZ is composed of bands of reflectors dipping at angles of 20°-35° extending to the lower crust. These reflectors were also well imaged on the coincident near-vertical reflection data. Reflectors under the Britt domain to the east of the GFTZ have a shallower dip than those along the zone. The structure of the crust under the Manitoulin terrane to the west of the GFTZ is laterally homogeneous with a major intracrustal reflector at a depth of 17-20 km below the surface. Poisson's ratio is

  5. Relation between cusp ion structures and dayside reconnection for four IMF clock angles: OpenGGCM-LTPT results

    NASA Astrophysics Data System (ADS)

    Connor, H. K.; Raeder, J.; Sibeck, D. G.; Trattner, K. J.

    2015-06-01

    When, where, and which type of reconnection (antiparallel or component) happens on the dayside magnetopause are long-standing unsolved questions due to insufficient in situ observation of reconnection sites. Previous studies showed that the dispersed ion signatures observed in the magnetospheric cusps depend on the reconnection mechanism, suggesting that cusp ion signatures can be a good tool to investigate the locations and properties of dayside reconnection. We investigate this close relation between cusp signatures and magnetopause reconnection for four different interplanetary magnetic field (IMF) clock angles (CA) using the Open Global Geospace Circulation Model (OpenGGCM) and the Liouville Theorem Particle Tracer(LTPT). OpenGGCM produces dayside reconnection under the resistive MHD theory, and LTPT calculates cusp ion signatures caused by the simulated reconnection. Our model results show that for CA = 0°, antiparallel reconnection at both the northern and southern lobes causes a reverse dispersion in which ion energies increase with increasing latitude. For CA = 60°, unsteady antiparallel reconnection at both the northern and southern lobes causes double reverse dispersions. For CA = 120°, component reconnection near the subsolar point produces a dispersionless signature in the low-latitude cusp, and antiparallel reconnection on the duskside northern magnetopause produces a normal dispersion in the high-latitude cusp in which ion energies decrease with increasing latitude. For CA = 180°, antiparallel reconnection near the subsolar point causes a normal dispersion.

  6. Backscattering enhancement for Marshall-Palmer distributed rains for a W-band nadir-pointing radar with a finite beam width

    NASA Technical Reports Server (NTRS)

    Kobayashi, Satoru; Tanelli, Simone; Im, Eastwood; Oguchi, Tomohiro

    2005-01-01

    In this paper, we expand the previous theory to be applied to a generic drop size distribution with spheroidal raindrops including spherical raindrops. Results will be used to discuss the multiple scattering effects on the backscatter measurements acquired by a W-band nadir-pointing radar.

  7. Identifying the occurrence of lightning and transient luminous events by nadir spectrophotometric observation

    NASA Astrophysics Data System (ADS)

    Adachi, Toru; Sato, Mitsuteru; Ushio, Tomoo; Yamazaki, Atsushi; Suzuki, Makoto; Kikuchi, Masayuki; Takahashi, Yukihiro; Inan, Umran S.; Linscott, Ivan; Hobara, Yasuhide; Frey, Harald U.; Mende, Stephen B.; Chen, Alfred B.; Hsu, Rue-Ron; Kusunoki, Kenichi

    2016-07-01

    We propose a new technique to identify the occurrence of lightning and transient luminous events (TLEs) using multicolor photometric data obtained by space borne nadir measurements. We estimate the spectral characteristics of lightning and TLEs by converting the optical data obtained by the ISUAL limb experiment to the GLIMS nadir geometry. We find that the estimated spectral shapes of TLE-accompanied lightning are clearly different from those of pure lightning. The obtained results show that (1) the intensity of FUV signals and (2) the ratio of 337/red (609-753 nm) spectral irradiance are useful to identify the occurrence of TLEs. The occurrence probabilities of TLEs are 10%, 40%, 80%, in the case of lightning events having the 337/red spectral irradiance ratio of 0.95, 2.95, 14.79, respectively. By using the 60% criterion of the 337/red ratio and the existence of FUV emissions, we classify the 1039 GLIMS-observed lightning events into 828 pure lightning and 211 TLE-accompanied lightning. Since the GLIMS trigger level is adjusted to observe extremely-bright events, the occurrence probability of TLEs obtained here most probably reflects the characteristics of energetic lightning. The estimated global map is consistent with previously determined distributions: the highest activities of lightning and TLEs are found over the North/South American continents, African continent, and Asian maritime regions. While the absolute occurrence number of pure lightning and TLE-accompanied lightning are found to maximize in the equatorial region, the occurrence probability of TLEs possibly increase somewhat in the mid-latitude region. Since the occurrence probabilities of TLEs are higher over the ocean than over land, it is likely that the GLIMS-observed TLEs are due primarily to elves which tends to occur more frequently over the ocean.

  8. Preliminary results from a subsonic high-angle-of-attack flush airdata sensing (HI-FADS) system - Design, calibration, algorithm development, and flight test evaluation

    NASA Technical Reports Server (NTRS)

    Whitmore, Stephen A.; Moes, Timothy R.; Larson, Terry J.

    1990-01-01

    A nonintrusive high angle-of-attack flush airdata sensing (HI-FADS) system was installed and flight-tested on the F-18 high alpha research vehicle. This paper discusses the airdata algorithm development and composite results expressed as airdata parameter estimates and describes the HI-FADS system hardware, calibration techniques, and algorithm development. An independent empirical verification was performed over a large portion of the subsonic flight envelope. Test points were obtained for Mach numbers from 0.15 to 0.94 and angles of attack from -8.0 to 55.0 deg. Angles of sideslip ranged from -15.0 to 15.0 deg, and test altitudes ranged from 18,000 to 40,000 ft. The HI-FADS system gave excellent results over the entire subsonic Mach number range up to 55 deg angle of attack. The internal pneumatic frequency response of the system is accurate to beyond 10 Hz.

  9. In-flight flow visualization results from the X-29A aircraft at high angles of attack

    NASA Technical Reports Server (NTRS)

    Delfrate, John H.; Saltzman, John A.

    1992-01-01

    Flow visualization techniques were used on the X-29A aircraft at high angles of attack to study the vortical flow off the forebody and the surface flow on the wing and tail. The forebody vortex system was studied because asymmetries in the vortex system were suspected of inducing uncommanded yawing moments at zero sideslip. Smoke enabled visualization of the vortex system and correlation of its orientation with flight yawing moment data. Good agreement was found between vortex system asymmetries and the occurrence of yawing moments. Surface flow on the forward-swept wing of the X-29A was studied using tufts and flow cones. As angle of attack increased, separated flow initiated at the root and spread outboard encompassing the full wing by 30 deg angle of attack. In general, the progression of the separated flow correlated well with subscale model lift data. Surface flow on the vertical tail was also studied using tufts and flow cones. As angle of attack increased, separated flow initiated at the root and spread upward. The area of separated flow on the vertical tail at angles of attack greater than 20 deg correlated well with the marked decrease in aircraft directional stability.

  10. The Caribbean-South American plate boundary at 65°W: Results from wide-angle seismic data

    NASA Astrophysics Data System (ADS)

    Bezada, M. J.; Magnani, M. B.; Zelt, C. A.; Schmitz, M.; Levander, A.

    2010-08-01

    We present the results of the analysis of new wide-angle seismic data across the Caribbean-South American plate boundary in eastern Venezuela at about 65°W. The ˜500 km long profile crosses the boundary in one of the few regions dominated by extensional structures, as most of the southeastern Caribbean margin is characterized by the presence of fold and thrust belts. A combination of first-arrival traveltime inversion and simultaneous inversion of PmP and Pn arrivals was used to develop a P wave velocity model of the crust and the uppermost mantle. At the main strike-slip fault system, we image the Cariaco Trough, a major pull-apart basin along the plate boundary. The crust under the Southern Caribbean Deformed Belt exhibits a thickness of ˜15 km, suggesting that the Caribbean Large Igneous Province extends to this part of the Caribbean plate. The velocity structures of basement highs and offshore sedimentary basins imaged by the profile are comparable to those of features found in other parts of the margin, suggesting similarities in their tectonic history. We do not image an abrupt change in Moho depth or velocity structure across the main strike-slip system, as has been observed elsewhere along the margin. It is possible that a terrane of Caribbean island arc origin was accreted to South America at this site and was subsequently bisected by the strike-slip fault system. The crust under the continental portion of the profile is thinner than observed elsewhere along the margin, possibly as a result of thinning during Jurassic rifting.

  11. NADIR: A prototype system for detecting network and file system abuse

    SciTech Connect

    Hochberg, J.G.; Jackson, K.A.; Stallings, C.A.; McClary, J.F.; DuBois, D.H.; Ford, J.R.

    1992-10-01

    This paper describes the design of a prototype computer misuse detection system for the Los Alamos Notional Laboratory`s Integrated Computing Network (ICN). This automated expert system, the Network Anomaly Detection and Intrusion Reporter (NADIR), streamlines and supplements the manual audit record review traditionally performed by security auditors. NADIR compares network activity, as summarized in weekly profiles of individual users and the ICN as a whole, against expert rules that define security policy, improper or suspicious behavior, and normal user activity. NADIR reports suspicious behavior to security auditors and provides tools to aid in follow-up investigations. This paper describes analysis by NADIR of two types of ICN activity: user authentication and access control, and mass file storage. It highlights system design issues of data handling, exploiting existing auditing systems, and performing audit analysis at the network level.

  12. NADIR: A prototype system for detecting network and file system abuse

    SciTech Connect

    Hochberg, J.G.; Jackson, K.A.; Stallings, C.A.; McClary, J.F.; DuBois, D.H.; Ford, J.R.

    1992-01-01

    This paper describes the design of a prototype computer misuse detection system for the Los Alamos Notional Laboratory's Integrated Computing Network (ICN). This automated expert system, the Network Anomaly Detection and Intrusion Reporter (NADIR), streamlines and supplements the manual audit record review traditionally performed by security auditors. NADIR compares network activity, as summarized in weekly profiles of individual users and the ICN as a whole, against expert rules that define security policy, improper or suspicious behavior, and normal user activity. NADIR reports suspicious behavior to security auditors and provides tools to aid in follow-up investigations. This paper describes analysis by NADIR of two types of ICN activity: user authentication and access control, and mass file storage. It highlights system design issues of data handling, exploiting existing auditing systems, and performing audit analysis at the network level.

  13. Development of a Model to Correct Multi-View Angle above Water Measurements for the Analysis of the Bidirectional Reflectance of Coral and Other Reef Substrates

    NASA Astrophysics Data System (ADS)

    Miller, I.; Forster, B. C.; Laffan, S. W.

    2012-07-01

    Spectral reflectance characteristics of substrates in a coral reef environment are often measured in the field by viewing a substrate at nadir. However, viewing a substrate from multiple angles would likely result in different spectral characteristics for most coral reef substrates and provide valuable information on structural properties. To understand the relationship between the morphology of a substrate and its spectral response it is necessary to correct the observed above-water radiance for the effects of atmosphere and water attenuation, at a number of view and azimuth angles. In this way the actual surface reflectance can be determined. This research examines the air-water surface interaction for two hypothetical atmospheric conditions (clear Rayleigh scattering and totally cloudcovered) and the global irradiance reaching the benthic surface. It accounts for both water scattering and absorption, with simplifications for shallow water conditions, as well as the additive effect of background reflectance being reflected at the water-air surface at angles greater than the critical refraction angle (~48°). A model was developed to correct measured above-water radiance along the refracted view angle for its decrease due to path attenuation and the "n squared law of radiance" and the additive surface reflectance. This allows bidirectional benthic surface reflectance and nadir-normalised reflectance to be determined. These theoretical models were adapted to incorporate above-water measures relative to a standard, diffuse, white reference panel. The derived spectral signatures of a number of coral and non-coral benthic surfaces compared well with other published results, and the signatures and nadir normalised reflectance of the corals and other benthic surface classes indicate good class separation.

  14. TES/Aura L2 Ozone (O3) Lite Nadir (TL2O3LN)

    Atmospheric Science Data Center

    2015-08-26

    TES/Aura L2 Ozone (O3) Lite Nadir (TL2O3LN) News:  TES News ... Level:  L2 Instrument:  TES/Aura L2 Ozone Spatial Coverage:  5.3 km nadir Spatial ... OPeNDAP Access:  OPeNDAP Parameters:  Ozone Order Data:  Reverb:   Order Data Guide ...

  15. TES/Aura L2 Carbon Dioxide (CO2) Lite Nadir (TL2CO2LN)

    Atmospheric Science Data Center

    2015-06-24

    TES/Aura L2 Carbon Dioxide (CO2) Lite Nadir (TL2CO2LN) News:  TES ... Level:  L2 Instrument:  TES/Aura L2 Carbon Dioxide Spatial Coverage:  5.3 km nadir ... OPeNDAP Access:  OPeNDAP Parameters:  Carbon Dioxide Order Data:  Reverb:   Order Data ...

  16. TES/Aura L2 Ammonia (NH3) Lite Nadir (TL2NH3LN)

    Atmospheric Science Data Center

    2015-08-26

    TES/Aura L2 Ammonia (NH3) Lite Nadir (TL2NH3LN) News:  TES News ... Level:  L2 Instrument:  TES/Aura L2 Ammonia Spatial Coverage:  5.3 km nadir Spatial ... OPeNDAP Access:  OPeNDAP Parameters:  Ammonia Order Data:  Reverb:   Order Data ...

  17. KaRIn on SWOT: modeling and simulation of near-nadir Ka-band interferometric SAR images

    NASA Astrophysics Data System (ADS)

    Fjørtoft, Roger; Koudogbo, Fifamè; Duro, Javier; Ruiz, Christian; Gaudin, Jean-Marc; Mallet, Alain; Pourthie, Nadine; Lion, Christine; Ordoqui, Patrick; Arnaud, Alain

    2010-10-01

    The principal instrument of the wide-swath altimetry mission SWOT is KaRIn, a Ka-band interferometric SAR system operating on near-nadir swaths on both sides of the satellite track. Due to the short wavelength and particular observation geometry, there are very limited reports on the backscattering from natural surfaces. Simulators that cover both radiometric and geometric aspects are therefore developed in the framework of the CNES phase 0 and A studies of SWOT. This article presents the modeling and simulation approaches that have been adopted, and shows some preliminary simulation results.

  18. Comparing nadir and limb observations of polar mesospheric clouds: The effect of the assumed particle size distribution

    NASA Astrophysics Data System (ADS)

    Bailey, Scott M.; Thomas, Gary E.; Hervig, Mark E.; Lumpe, Jerry D.; Randall, Cora E.; Carstens, Justin N.; Thurairajah, Brentha; Rusch, David W.; Russell, James M.; Gordley, Larry L.

    2015-05-01

    Nadir viewing observations of Polar Mesospheric Clouds (PMCs) from the Cloud Imaging and Particle Size (CIPS) instrument on the Aeronomy of Ice in the Mesosphere (AIM) spacecraft are compared to Common Volume (CV), limb-viewing observations by the Solar Occultation For Ice Experiment (SOFIE) also on AIM. CIPS makes multiple observations of PMC-scattered UV sunlight from a given location at a variety of geometries and uses the variation of the radiance with scattering angle to determine a cloud albedo, particle size distribution, and Ice Water Content (IWC). SOFIE uses IR solar occultation in 16 channels (0.3-5 μm) to obtain altitude profiles of ice properties including the particle size distribution and IWC in addition to temperature, water vapor abundance, and other environmental parameters. CIPS and SOFIE made CV observations from 2007 to 2009. In order to compare the CV observations from the two instruments, SOFIE observations are used to predict the mean PMC properties observed by CIPS. Initial agreement is poor with SOFIE predicting particle size distributions with systematically smaller mean radii and a factor of two more albedo and IWC than observed by CIPS. We show that significantly improved agreement is obtained if the PMC ice is assumed to contain 0.5% meteoric smoke by mass, in agreement with previous studies. We show that the comparison is further improved if an adjustment is made in the CIPS data processing regarding the removal of Rayleigh scattered sunlight below the clouds. This change has an effect on the CV PMC, but is negligible for most of the observed clouds outside the CV. Finally, we examine the role of the assumed shape of the ice particle size distribution. Both experiments nominally assume the shape is Gaussian with a width parameter roughly half of the mean radius. We analyze modeled ice particle distributions and show that, for the column integrated ice distribution, Log-normal and Exponential distributions better represent the range

  19. Increase in the maximum lift of an airplane wing due to a sudden increase in its effective angle of attack resulting from a gust

    NASA Technical Reports Server (NTRS)

    Kramer, Max

    1932-01-01

    Wind-tunnel tests are described, in which the angle of attack of a wing model was suddenly increased (producing the effect of a vertical gust) and the resulting forces were measured. It was found that the maximum lift coefficient increases in proportion to the rate of increase in the angle of attack. This fact is important for the determination of the gust stresses of airplanes with low wing loading. The results of the calculation of the corrective factor are given for a high-performance glider and a light sport plane of conventional type.

  20. The ExoMars Trace Gas Orbiter NOMAD Spectrometer Suite for Nadir and Solar Occultation Observations of Mars' Atmosphere

    NASA Astrophysics Data System (ADS)

    Thomas, Ian; Carine Vandaele, Ann; López-Moreno, José Juan; Patel, Manish; Bellucci, Giancarlo; Drummond, Rachel; Neefs, Eduard; Depiesse, Cedric; Daerden, Frank; Rodriguez-Gómez, Julio; Neary, Lori; Robert, Séverine; Willame, Yannick; Mahieux, Arnaud

    2015-04-01

    NOMAD (Nadir and Occultation for MArs Discovery) is one of four instruments on board the ExoMars Trace Gas Orbiter, scheduled for launch in January 2016 and to begin nominal science mission around Mars in late 2017. It consists of a suite of three high-resolution spectrometers - Solar Occultation (SO), LNO (Limb Nadir and Occultation) and UVIS (Ultraviolet-Visible) - which will generate a huge dataset of Martian atmospheric observations during the mission, across a wide spectral range. Specifically, the SO spectrometer channel will perform occultation measurements, operating between 2.2-4.3μm at a resolution of 0.15cm-1, with 180-1000m vertical spatial resolution and an SNR of 1500-3000. LNO will perform limb scanning, nadir and occultation measurements, operating between 2.2-3.8μm at a resolution of 0.3cm-1. In nadir, global coverage will extend between ±74O latitude with an IFOV of 0.5x17km on the surface. This channel can also make occultation measurements should the SO channel fail. UVIS will make limb, nadir and occultation measurements between 200-650nm, at a resolution of 1nm. It will have 300-1000m vertical resolution during occultation and 5x60km ground resolution during 15s nadir observations. An order-of-magnitude increase in spectral resolution over previous instruments will allow NOMAD to map previously unresolvable gas species, such as important trace gases and isotopes. CO, CO2, H2O, C2H2, C2H4, C2H6, H2CO, CH4, SO2, H2S, HCl, O3 and several isotopologues of methane and water will be detectable, providing crucial measurements of the Martian D/H and methane isotope ratios. It will also be possible to map the sources and sinks of these gases, such as regions of surface volcanism/outgassing and atmospheric production, over the course of an entire Martian year, to further constrain atmospheric dynamics and climatology. NOMAD will also continue to monitor the Martian water, carbon, ozone and dust cycles, extending existing datasets made by successive

  1. Towards 3D Matching of Point Clouds Derived from Oblique and Nadir Airborne Imagery

    NASA Astrophysics Data System (ADS)

    Zhang, Ming

    Because of the low-expense high-efficient image collection process and the rich 3D and texture information presented in the images, a combined use of 2D airborne nadir and oblique images to reconstruct 3D geometric scene has a promising market for future commercial usage like urban planning or first responders. The methodology introduced in this thesis provides a feasible way towards fully automated 3D city modeling from oblique and nadir airborne imagery. In this thesis, the difficulty of matching 2D images with large disparity is avoided by grouping the images first and applying the 3D registration afterward. The procedure starts with the extraction of point clouds using a modified version of the RIT 3D Extraction Workflow. Then the point clouds are refined by noise removal and surface smoothing processes. Since the point clouds extracted from different image groups use independent coordinate systems, there are translation, rotation and scale differences existing. To figure out these differences, 3D keypoints and their features are extracted. For each pair of point clouds, an initial alignment and a more accurate registration are applied in succession. The final transform matrix presents the parameters describing the translation, rotation and scale requirements. The methodology presented in the thesis has been shown to behave well for test data. The robustness of this method is discussed by adding artificial noise to the test data. For Pictometry oblique aerial imagery, the initial alignment provides a rough alignment result, which contains a larger offset compared to that of test data because of the low quality of the point clouds themselves, but it can be further refined through the final optimization. The accuracy of the final registration result is evaluated by comparing it to the result obtained from manual selection of matched points. Using the method introduced, point clouds extracted from different image groups could be combined with each other to build a

  2. An Overview of Three-year JEM-GLIMS Nadir Observations of Lightning and TLEs

    NASA Astrophysics Data System (ADS)

    Sato, M.; Ushio, T.; Morimoto, T.; Adachi, T.; Kikuchi, H.; Suzuki, M.; Yamazaki, A.; Takahashi, Y.; Inan, U.; Linscott, I.; Hobara, Y.

    2015-12-01

    JEM-GLIMS nadir observations of lightning and TLEs at the ISS started from November 2012 and successfully ended on August 2015. For three-year observation period, JEM-GLIMS succeeded in detecting over 8,000 lightning events and 670 TLEs. The detected optical emissions of sprites showed clear horizontal displacement with the range of 10-20 km from the peak location of the +CG emissions and from the +CG locations detected by NLDN and WWLLN. Using VITF electric field waveform data, source locations of VHF pulses excited by the parent CG discharges are estimated. It is found that the possible VHF source locations were mostly located within the area of the parent lightning emissions. These facts may imply that the center region of the neutralized charge by CG discharges in the thundercloud located near the return stroke point and that the some seed conditions were established in advance at the sprite location before the occurrence of sprites. The global occurrence distributions and rates of lightning discharges and TLEs are also estimated. The estimated mean global occurrence rate of lightning discharges is ~1.5 events/s, which is smaller number than that derived from MicroLab-1/OTD and TRMM/LIS measurements. This may be originated in the fact that JEM-GLISM detected only intense lightning optical events due to the high threshold level for the event triggering. To the contrary, the estimated mean global occurrence rate of TLEs is ~9.8 events/min, which is two times higher than the ISUAL result. It is likely that JEM-GLIMS could detect dimmer optical emissions of TLEs than ISUAL since the distance between the JEM-GLIMS instruments and TLEs is much closer. At the presentation, we will summarize the results derived from three-year JEM-GLIMS nadir observations. We will discuss possible occurrence conditions of sprites, properties of global occurrence rates of lightning and TLEs, and their LT dependences more in detail.

  3. Note on the Effect of Horizontal Gradients for Nadir-Viewing Microwave and Infrared Sounders

    NASA Technical Reports Server (NTRS)

    Joiner, J.; Poli, P.

    2004-01-01

    Passive microwave and infrared nadir sounders such as the Advanced Microwave Sounding Unit A (AMSU-A) and the Atmospheric InfraRed Sounder (AIRS), both flying on NASA s EOS Aqua satellite, provide information about vertical temperature and humidity structure that is used in data assimilation systems for numerical weather prediction and climate applications. These instruments scan cross track so that at the satellite swath edges, the satellite zenith angles can reach approx. 60 deg. The emission path through the atmosphere as observed by the satellite is therefore slanted with respect to the satellite footprint s zenith. Although radiative transfer codes currently in use at operational centers use the appropriate satellite zenith angle to compute brightness temperature, the input atmospheric fields are those from the vertical profile above the center of the satellite footprint. If horizontal gradients are present in the atmospheric fields, the use of a vertical atmospheric profile may produce an error. This note attempts to quantify the effects of horizontal gradients on AIRS and AMSU-A channels by computing brightness temperatures with accurate slanted atmospheric profiles. We use slanted temperature, water vapor, and ozone fields from data assimilation systems. We compare the calculated slanted and vertical brightness temperatures with AIRS and AMSU-A observations. We show that the effects of horizontal gradients on these sounders are generally small and below instrument noise. However, there are cases where the effects are greater than the instrument noise and may produce erroneous increments in an assimilation system. The majority of the affected channels have weighting functions that peak in the upper troposphere (water vapor sensitive channels) and above (temperature sensitive channels) and are unlikely t o significantly impact tropospheric numerical weather prediction. However, the errors could be significant for other applications such as stratospheric

  4. Retrieval of tropospheric ozone columns from SCIAMACHY limb-nadir matching observations

    NASA Astrophysics Data System (ADS)

    Ebojie, F.; Savigny, C.; Ladstätter-Weissenmayer, A.; Bötel, S.; Weber, M.; Alexei, R.; Bovensmann, H.; Burrows, J.

    2012-04-01

    Satellite observations of tropospheric ozone are of critical importance in obtaining a global and more thorough knowledge of the phenomena affecting air quality. Tropospheric ozone has a significant adverse effect on the climate system. In the lower troposphere, during summer, it is a major constituent of photochemical smog and excess of it is toxic to the ecosystem, animal and man. It is equally known as a major oxidant and also involved in the production of other oxidants such as hydroxyl (OH) radicals. In the middle and upper troposphere, ozone acts as a greenhouse gas. The retrieval of tropospheric ozone from UV/VIS/NIR satellite spectrometer such as the Scanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) instrument onboard the ESA satellite Envisat is difficult because only about 10 % of the Total Ozone Column (TOC) is in the troposphere. In this analysis we present the retrieval of tropospheric ozone columns from SCIAMACHY limb-nadir matching observations. This technique is a residual approach that involves the subtraction of the stratospheric ozone columns derived from the limb observations from the total ozone columns derived from the nadir observations. The stratospheric ozone columns were derived by integrating the stratospheric ozone profiles from the tropopause, which was obtained from the re-analyses data of the European Centre for Medium-Range Weather Forecasts (ECMWF) in 1.5o x 1.5o x 91 levels based on both the thermal definition of tropopause using the WMO lapse-rate criterion as well as the potential vorticity definition of the tropopause. The total ozone columns were on the other hand retrieved using the Weighting Function DOAS algorithm (WFDOAS) at the spectral window of 326.6 - 334.5 nm. Equally of importance in our analysis is the tropospheric ozone columns derived from the ozonesondes by integrating the tropospheric ozone profiles from the bottom to the top of the troposphere, which was determined from the

  5. Preliminary results from a subsonic high angle-of-attack flush airdata sensing (HI-FADS) system: Design, calibration, and flight test evaluation

    NASA Technical Reports Server (NTRS)

    Whitmore, Stephen A.; Moes, Timothy R.; Larson, Terry J.

    1990-01-01

    A nonintrusive high angle-of-attack flush airdata sensing (HI-FADS) system was installed and flight-tested on the F-18 high alpha research flight vehicle. The system is a matrix of 25 pressure orifices in concentric circles on the nose of the vehicle. The orifices determine angles of attack and sideslip, Mach number, and pressure altitude. Pressure was transmitted from the orifices to an electronically scanned pressure module by lines of pneumatic tubing. The HI-FADS system was calibrated and demonstrated using dutch roll flight maneuvers covering large Mach, angle-of-attack, and sideslip ranges. Reference airdata for system calibration were generated by a minimum variance estimation technique blending measurements from two wingtip airdata booms with inertial velocities, aircraft angular rates and attitudes, precision radar tracking, and meteorological analyses. The pressure orifice calibration was based on identifying empirical adjustments to modified Newtonian flow on a hemisphere. Calibration results are presented. Flight test results used all 25 orifices or used a subset of 9 orifices. Under moderate maneuvering conditions, the HI-FADS system gave excellent results over the entire subsonic Mach number range up to 55 deg angle of attack. The internal pneumatic frequency response of the system is accurate to beyond 10 Hz. Aerodynamic lags in the aircraft flow field caused some performance degradation during heavy maneuvering.

  6. Six years of total ozone column measurements from SCIAMACHY nadir observations

    NASA Astrophysics Data System (ADS)

    Lerot, C.; van Roozendael, M.; van Geffen, J.; van Gent, J.; Fayt, C.; Spurr, R.; Lichtenberg, G.; von Bargen, A.

    2008-11-01

    Total O3 columns have been retrieved from six years of SCIAMACHY nadir UV radiance measurements using SDOAS, an adaptation of the GDOAS algorithm previously developed at BIRA-IASB for the GOME instrument. GDOAS and SDOAS have been implemented by the German Aerospace Center (DLR) in the version 4 of the GOME Data Processor (GDP) and in version 3 of the SCIAMACHY Ground Processor (SGP), respectively. The processors are being run at the DLR processing centre on behalf of the European Space Agency (ESA). We first focus on the description of the SDOAS algorithm with particular attention to the impact of uncertainties on the reference O3 absorption cross-sections. Second, the resulting SCIAMACHY total ozone data set is globally evaluated through large-scale comparisons with results from GOME and OMI as well as with ground-based correlative measurements. The various total ozone data sets are found to agree within 2% on average. However, a negative trend of 0.2-0.4%/year has been identified in the SCIAMACHY O3 columns; this probably originates from instrumental degradation effects that have not yet been fully characterized.

  7. Six years of total ozone column measurements from SCIAMACHY nadir observations

    NASA Astrophysics Data System (ADS)

    Lerot, C.; van Roozendael, M.; van Geffen, J.; van Gent, J.; Fayt, C.; Spurr, R.; Lichtenberg, G.; von Bargen, A.

    2009-04-01

    Total O3 columns have been retrieved from six years of SCIAMACHY nadir UV radiance measurements using SDOAS, an adaptation of the GDOAS algorithm previously developed at BIRA-IASB for the GOME instrument. GDOAS and SDOAS have been implemented by the German Aerospace Center (DLR) in the version 4 of the GOME Data Processor (GDP) and in version 3 of the SCIAMACHY Ground Processor (SGP), respectively. The processors are being run at the DLR processing centre on behalf of the European Space Agency (ESA). We first focus on the description of the SDOAS algorithm with particular attention to the impact of uncertainties on the reference O3 absorption cross-sections. Second, the resulting SCIAMACHY total ozone data set is globally evaluated through large-scale comparisons with results from GOME and OMI as well as with ground-based correlative measurements. The various total ozone data sets are found to agree within 2% on average. However, a negative trend of 0.2-0.4%/year has been identified in the SCIAMACHY O3 columns; this probably originates from instrumental degradation effects that have not yet been fully characterized.

  8. Perception of Perspective Angles

    PubMed Central

    2015-01-01

    We perceive perspective angles, that is, angles that have an orientation in depth, differently from what they are in physical space. Extreme examples are angles between rails of a railway line or between lane dividers of a long and straight road. In this study, subjects judged perspective angles between bars lying on the floor of the laboratory. Perspective angles were also estimated from pictures taken from the same point of view. Converging and diverging angles were judged to test three models of visual space. Four subjects evaluated the perspective angles by matching them to nonperspective angles, that is, angles between the legs of a compass oriented in the frontal plane. All subjects judged both converging and diverging angles larger than the physical angle and smaller than the angles in the proximal stimuli. A model of shallow visual space describes the results. According to the model, lines parallel to visual lines, vanishing at infinity in physical space, converge to visual lines in visual space. The perceived shape of perspective angles is incompatible with the perceived length and width of the bars. The results have significance for models of visual perception and practical implications for driving and flying in poor visibility conditions. PMID:27433312

  9. Perception of Perspective Angles.

    PubMed

    Erkelens, Casper J

    2015-06-01

    We perceive perspective angles, that is, angles that have an orientation in depth, differently from what they are in physical space. Extreme examples are angles between rails of a railway line or between lane dividers of a long and straight road. In this study, subjects judged perspective angles between bars lying on the floor of the laboratory. Perspective angles were also estimated from pictures taken from the same point of view. Converging and diverging angles were judged to test three models of visual space. Four subjects evaluated the perspective angles by matching them to nonperspective angles, that is, angles between the legs of a compass oriented in the frontal plane. All subjects judged both converging and diverging angles larger than the physical angle and smaller than the angles in the proximal stimuli. A model of shallow visual space describes the results. According to the model, lines parallel to visual lines, vanishing at infinity in physical space, converge to visual lines in visual space. The perceived shape of perspective angles is incompatible with the perceived length and width of the bars. The results have significance for models of visual perception and practical implications for driving and flying in poor visibility conditions. PMID:27433312

  10. Impact of baseline and nadir neutrophil index in non-small cell lung cancer and ovarian cancer patients: Assessment of chemotherapy for resolution of unfavourable neutrophilia

    PubMed Central

    2013-01-01

    Background Chronic inflammation has been recognized to foster tumour development. Whether chemotherapy can be used to neutralize chronic inflammation is unclear. Methods We evaluated baseline and nadir neutrophils in 111 patients (pts.) with non-small cell lung cancer (NSCLC) and 118 pts. with ovarian cancer (OC) treated with chemotherapy administered with dose-individualization to achieve nadir neutropenia of 1.5. We used predefined baseline neutrophil cut-offs 4.5 × 109/L (NSCLC) and 3.9 × 109/L (OC). Results Absence of chemotherapy-induced nadir neutropenia (CTCAE grade 0, neutrophils ≥ LLN) was seen in 23% of OC and 25% of NSCLC pts. Absence of nadir neutropenia was associated with decreased overall survival (OS) compared with presence (>grade 0) of neutropenia (9 vs. 14 months, P = 0.004 for NSCLC and 23 vs. 56 months; P = 0.01 for OC). Obtaining grade 3/4 neutropenia did not improve survival compared with grade 1/2 neutropenia. In multivariate analyses, baseline neutrophils ≥4.5 × 109/L (HR: 2.0; 95% CI: 1.11-3.44;P = 0.02) and absence of nadir neutropenia (HR: 1.6; 95% CI: 1.02-2.65;P = 0.04) for NSCLC and absence of nadir neutropenia (HR: 1.7; 95% CI: 1.04;2.93;P = 0.04) for OC were independently associated with short OS. Three prognostic neutrophil index (NI) groups were defined. Favourable NI: low baseline neutrophils and presence of nadir neutropenia (>grade 0), Intermediate NI: elevated baseline neutrophils and presence of nadir neutropenia (>grade 0), and Poor NI: elevated baseline neutrophils and absence of nadir neutropenia (grade 0). For NSCLC patients, the median OS was 18.0, 13.4, and 8.8 months for favourable, intermediate and poor NI, respectively (fav vs. poor P = 0.002; fav vs. intermed P = 0.04; and intermed vs. poor P = 0.03). For OC patients, median OS was 69, 52 and 23 months for favourable, intermediate and poor NI, respectively (fav vs. poor P = 0.03; fav vs. intermed P = 0.3; and intermed vs

  11. Recent results in the study of heavy-ion elastic scattering at large angles. [180/sup 0/

    SciTech Connect

    Barrette, J.; Kahana, S.

    1983-01-01

    The observation, a few years ago, of unexpected large cross sections at backward angles in the elastic scattering of mass-asymmetric heavy ion systems gave us hope that we could learn something new and more precise on the properties of the average ion-ion potential. The subsequent observation of broad regular structures in the elastic and inelastic excitation functions near theta/sub cm/ = 180/sup 0/ were also very promising. Numerous models were proposed to explain some or all the observed features. These models can be divided mainly in two groups. Some try to modify directly the average optical potential whereas others associate the observed cross sections to a modification of specific partial waves outside the scope of the optical potential. This separation in two groups is not always clear since as demonstrated adding a Regge pole to a strongly absorbing potential is under some conditions perfectly equivalent to changing the shape of this potential. Similarly the resonances added to an S matrix can be understood as the manifestation of the potential resonances of a completely different optical potential. We describe recent calculations which have been carried on to try to understand the behavior of the data near the barrier.

  12. Impact of Spectroscopic Line Parameters on Carbon Monoxide Column Density Retrievals from Shortwave Infrared Nadir Observations

    NASA Astrophysics Data System (ADS)

    Schmidt, Denise; Gimeno Garcia, Sebastian; Schreier, Franz; Lichtenberg, Gunter

    2015-06-01

    Among the various input data required for the retrieval of atmospheric state parameters from infrared remote sensing observations molecular spectroscopy line data have a central role, because their quality is critical for the quality of the final product. Here we discuss the impact of the line parameters on vertical column densities (VCD) estimated from short wave infrared nadir observations. Using BIRRA (the Beer InfraRed Retrieval Algorithm) comprising a line-by-line radiative transfer code (forward model) and a separable nonlinear least squares solver for inversion we retrieve carbon monoxide from observations of SCIAMACHY aboard Envisat. Retrievals using recent versions of HITRAN und GEISA have been performed and the results are compared in terms of residual norms, molecular density scaling factors, their corresponding errors, and the final VCD product. The retrievals turn out to be quite similar for all three databases, so a definite recommendation in favor of one of these databases is difficult for the considered spectral range around 2:3 μm . Nevertheless, HITRAN 2012 appears to be advantageous when evaluating the different quality criteria.

  13. NLC occurrence frequency retrieval from SCIAMACHY, GOME and GOME-2 nadir data

    NASA Astrophysics Data System (ADS)

    Langowski, Martin; Von Savigny, Christian

    2016-07-01

    Noctilucent clouds NLCs are clouds occurring in the polar summer mesopause region at about 82-86 km altitude, and they can be observed poleward of about 50 degrees latitude. Due to their high altitude, they can scatter sunlight to the ground, even if it is dark at the ground, which makes them a fascinating bright phenomenon in the summer night sky. First observations of NLCs were reported in the 1880ies after the eruption of the Krakatau volcano. Afterwards they were seen every year and current long time studies show, that their occurrence rate is well anticorrelated with solar activity and it increased over time for the last decades. Ever since the NLCs were observed it was discussed whether their increasing occurrence rate can be interpreted as a sign of climate change in the upper atmosphere. With the SCIAMACHY, GOME and GOME 2 nadir measurements, which are very similar for each instrument a long time dataset of over 20 years of data is available to retrieve NLC occurrence frequencies. All three instruments have a very stable local times with descending nodes ranging between 9:30 a.m. and 10:30 a.m.. We present the algorithm to retrieve NLC occurrence frequencies from these instruments and results of this retrieval.

  14. What's Your Angle on Angles?

    ERIC Educational Resources Information Center

    Browning, Christine A.; Garza-Kling, Gina; Sundling, Elizabeth Hill

    2007-01-01

    Although the nature of the research varies, as do concepts of angle, research in general supports the supposition that angle is a complex idea, best understood from a variety of perspectives. In fact, the concept of angle tends to be threefold, consisting of: (1) the traditional, static notion of two rays meeting at a common vertex; (2) the idea…

  15. Biodegradable 3D-Porous Collagen Matrix (Ologen) Compared with Mitomycin C for Treatment of Primary Open-Angle Glaucoma: Results at 5 Years

    PubMed Central

    Yuan, Fei; Li, Lei; Chen, Xiuping; Yan, Xiang; Wang, Liyang

    2015-01-01

    Purpose. To evaluate the effectiveness and safety of the Ologen as an aid for trabeculectomy performed for primary open-angle glaucoma compared with mitomycin C. Methods. In this prospective, randomized, parallel assignment, comparative study, 31 eyes of 21 primary open-angle glaucoma patients were allocated for trabeculectomy with the Ologen implant; another 32 eyes of 23 patients were treated with trabeculectomy augmented with mitomycin C. The patients were followed up for 5 years and evaluated for intraocular pressure, rate of success, status of the bleb, and adverse events. Result. The mean postoperative intraocular pressure was statistically different at 3 m, 6 m, 1 y, 3 y, and 5 y follow-up. The rates of both complete success (P = 0.017) and overall success (P = 0.031) in the Ologen group were significantly higher than those in the mitomycin C group. The difference of the bleb extent and vascularity was statistically significant in both groups. There was no significant difference in postoperative complication. Conclusions. Ologen provides higher rates of surgical success compared with mitomycin C for patients with primary open-angle glaucoma undergoing trabeculectomy. It may be a new, safe, simple, and effective therapeutic approach for treating primary open-angle glaucoma. PMID:26078875

  16. View angle dependence of MODIS liquid water path retrievals in warm oceanic clouds

    PubMed Central

    Horváth, Ákos; Seethala, Chellappan; Deneke, Hartwig

    2014-01-01

    We investigated the view angle dependence of domain mean Moderate Resolution Imaging Spectroradiometer (MODIS) liquid water path (LWP) and that of corresponding cloud optical thickness, effective radius, and liquid cloud fraction as proxy for plane-parallel retrieval biases. Independent Advanced Microwave Scanning Radiometer–EOS LWP was used to corroborate that the observed variations with sun-view geometry were not severely affected by seasonal/latitudinal changes in cloud properties. Microwave retrievals showed generally small (<10%) cross-swath variations. The view angle (cross-swath) dependence of MODIS optical thickness was weaker in backscatter than forward scatter directions and transitioned from mild ∩ shape to stronger ∪ shape as heterogeneity, sun angle, or latitude increased. The 2.2 µm effective radius variations always had a ∪ shape, which became pronounced and asymmetric toward forward scatter in the most heterogeneous clouds and/or at the lowest sun. Cloud fraction had the strongest and always ∪-shaped view angle dependence. As a result, in-cloud MODIS cloud liquid water path (CLWP) showed surprisingly good view angle (cross-swath) consistency, usually comparable to that of microwave retrievals, due to cancelation between optical thickness and effective radius biases. Larger (20–40%) nadir-relative increases were observed in the most extreme heterogeneity and sun angle bins, that is, typically in the polar regions, which, however, constituted only 3–8% of retrievals. The good consistency of MODIS in-cloud CLWP was lost for gridbox mean LWP, which was dominated by the strong cloud fraction increase with view angle. More worryingly, MODIS LWP exhibited significant and systematic absolute increases with heterogeneity and sun angle that is not present in microwave LWP. Key Points Microwave LWP shows small overall and cross-swath variations MODIS in-cloud LWP also shows good view angle consistency in most cases MODIS retrievals show strong

  17. Influence of subaqueous shelf angle on coastal plain-shelf-slope deposits resulting from a rise or fall in base-level

    SciTech Connect

    Wood, L.J.; Ethridge, F.G.; Schumm, S.A. )

    1991-03-01

    Extensive research in the past decade concerning the effects of base-level fluctuations on coastal plain-shelf-slope systems along passive margins has failed to properly assess the influence of the subaqueous shelf angle on the development, character, and preservation of the resulting deposits. A series of experiments were performed in a 4 m by 7 m flume to examine the effect that differing shelf angles have on a simulated coastal plain-shelf-slope system undergoing a cycle of base-level rise and fall. Results of the experiments indicate that the angle of the shelf affects (1) the amount of sediment available for deposition, (2) the timing of the influx of drainage basin sediment into the lower portions of the fluvial system, and (3) the width to depth ratio and sinuosity of fluvial systems that develop on the shelf. Base-level fall over a steep shelf results in deep, narrow, straight fluvial channels on the shelf and fine-grained, thick shelf-margin deltas. Depositional systems show high sedimentation rates, but a low ratio of coarse-grained to fine-grained sediment. Multiple fluvial incisions on the shelf are rapidly abandoned for a single incised valley. In contrast, gentle shelf angles result in shallow, wide, meandering fluvial channels on the shelf and coarser-grained, thinner shelf-margin deltas. Depositional systems have a lower sedimentation rate, but a high ratio of coarse-grained to fine-grained sediment. Multiple fluvial incisions on the shelf are active for a longer period of time. During subsequent base-level rise, deposits have a low potential for preservation owing to their thin nature and the slower rate at which transgression occurs over the shelf.

  18. Nadir and oblique canopy reflectance sensing for N application in corn

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Canopy reflectance sensing can be used to assess in-season crop nitrogen (N) health for subsequent control of N fertilization. The several sensor systems that are now commercially available have design and operational differences, including sensed wavelengths, size of the sensed area, and nadir vs. ...

  19. Using SOURCES to Examine the Nadir of Race Relations (1890-1920)

    ERIC Educational Resources Information Center

    LaVallee, Carol; Waring, Scott M.

    2015-01-01

    The "nadir of race relations" is a term used by historians to describe the time period after Reconstruction, 1890-1920. During this time, African Americans were free; some argue, however, that it was a worse time than when these individuals were enslaved (Brundage 1990; Woodward 2002). There is a debate whether this time period…

  20. TES/Aura L2 Water Vapor (H2O) Lite Nadir (TL2H2OLN)

    Atmospheric Science Data Center

    2015-06-16

    TES/Aura L2 Water Vapor (H2O) Lite Nadir (TL2H2OLN) News:  TES News ... Title:  TES Discipline:  Tropospheric Chemistry Version:  V6 Level:  L2 Instrument:  TES/Aura L2 Water Vapor Spatial Coverage:  5.3 km nadir ...

  1. The influence of polarization on box air mass factors for UV/vis nadir satellite observations

    NASA Astrophysics Data System (ADS)

    Hilboll, Andreas; Richter, Andreas; Rozanov, Vladimir V.; Burrows, John P.

    2015-04-01

    Tropospheric abundances of pollutant trace gases like, e.g., NO2, are often derived by applying the differential optical absorption spectroscopy (DOAS) method to space-borne measurements of back-scattered and reflected solar radiation. The resulting quantity, the slant column density (SCD), subsequently has to be converted to more easily interpretable vertical column densities by means of the so-called box air mass factor (BAMF). The BAMF describes the ratio of SCD and VCD within one atmospheric layer and is calculated by a radiative transfer model. Current operational and scientific data products of satellite-derived trace gas VCDs do not include the effect of polarization in their radiative transfer models. However, the various scattering processes in the atmosphere do lead to a distinctive polarization pattern of the observed Earthshine spectra. This study investigates the influence of these polarization patterns on box air mass factors for satellite nadir DOAS measurements of NO2 in the UV/vis wavelength region. NO2 BAMFs have been simulated for a multitude of viewing geometries, surface albedos, and surface altitudes, using the radiative transfer model SCIATRAN. The results show a potentially large influence of polarization on the BAMF, which can reach 10% and more close to the surface. A simple correction for this effect seems not to be feasible, as it strongly depends on the specific measurement scenario and can lead to both high and low biases of the resulting NO2 VCD. We therefore conclude that all data products of NO2 VCDs derived from space-borne DOAS measurements should include polarization effects in their radiative transfer model calculations, or at least include the errors introduced by using linear models in their uncertainty estimates.

  2. OSTEOSYNTHESIS OF PROXIMAL HUMERAL END FRACTURES WITH FIXED-ANGLE PLATE AND LOCKING SCREWS: TECHNIQUE AND RESULTS

    PubMed Central

    Cohen, Marcio; Amaral, Marcus Vinicius; Monteiro, Martim; Brandão, Bruno Lobo; Motta Filho, Geraldo Rocha

    2015-01-01

    Describe the results of proximal humeral fractures surgically treated with the Philos locking plate system. Method: Between March 2003 and October 2004 we prospectively reviewed 24 of 26 patients with proximal humerus fractures treated with a Philos plate. The mean follow-up time was 12 months and the mean age of patients was 57 years. Six patients had four-part proximal humerus fractures, 11 patients had three-part proximal humerus fractures, and nine patients had two-part proximal humerus fractures. Clinical evaluation was performed using the University of California at Los Angeles (UCLA) criteria. Results: The mean UCLA score was 30 points (17-34). All fractures showed union. Three patients showed fracture union at varus position. The mean UCLA score for these patients was 27 points. Conclusion: Osteosynthesis with Philos plate provides a stable fixation method with good functional outcome. PMID:26998460

  3. Preliminary investigation of the reststrahlen phenomenology at low-grazing angles

    NASA Astrophysics Data System (ADS)

    Harr, Richard; Polcha, Michael

    2005-06-01

    Detection of buried and flush buried landmines has been dangerous and time consuming for both military and humanitarian de-mining personnel throughout the world. In an effort to make the process safer, faster, and more reliable, scientists have successfully employed Ground Penetrating Radar (GPR) systems in nadir and near nadir viewing angles. Leveraging this successful technology, Forward-Looking Ground Penetrating Radar (FLGPR) technology, using low grazing angles, is being developed which promises to provide an increase in detection stand-off distance thereby increasing safety of personnel during land-based mine detection efforts. However, the application of GPR for the detection of buried plastic mines has been problematic, research has begun to exploit the comination of broadband and hyper-spectral passive electro-optical technologies with GPR technologies. One such embodiment is to use Forward Looking InfraRed (FLIR) technology with the intention to augment the capability of, and overcome limitations inherent to, current FLGPR technology. The emphasis in using FLIR is to understand and exploit specific spectral features which are complementary fo FLGPR and exhibited by buried metal and plastic mine targets. One spectral feature being investigated is the resstrahlen emission which results when soil is excavated or disturbed. This paper is a preliminary investigation of the performance of a vehicle based FLIR camera system for detecting resstrahlen emissions from disturbed soils. Specifically, this paper will examine the robustness of the resstrahlen feature in a forward-looking low grazing angle application. The data presented in this paper was collected at an eastern US Army testing site over targets deployed in soils which had been disturbed from one day before the start of the collection.

  4. LIDORT V2PLUS: a comprehensive radiative transfer package for UV/VIS/NIR nadir remote sensing

    NASA Astrophysics Data System (ADS)

    Spurr, Robert J. D.

    2004-02-01

    The LIDPORT V2PLUS radiative transfer package is designed for simulation and retrieval applications for nadir viewing remote sensing instruments such as GOME, GOME-2, SCIAMACHY, OMI and MODIS. The package is based on the LIDORT family of linearized discrete ordinate models, and it will deliver earthshine radiances, analytic profile, total column and surface property Jacobians. LIDORT V2PLUS includes a quasi-exact single scatter computation for all solar beams and the line of sight direction in a curved spherical-shell refracting atmosphere, and a full treatment of the diffuse radiation field in the pseudo-spherical approximation at all points along the line-of-sight. We give examples of radiances and O3 air mass factors at 325 nm, and Jacobians for O3 total column and profiles and for surface albedos, with particular emphasis on the wide-angle spherically-corrected viewing mode. We also look at the effect of horizontal inhomogeneity caused by varying surface properties along the line of sight.

  5. Photometric Characteristics of Sprites and Elves Derived from JEM-GLIMS Nadir Observations (Invited)

    NASA Astrophysics Data System (ADS)

    Sato, M.; Takahashi, Y.; Adachi, T.; Kobayashi, N.; Mihara, M.; Ushio, T.; Morimoto, T.; Suzuki, M.; Yamazaki, A.; Inan, U.; Linscott, I.

    2013-12-01

    The main goal of the JEM-GLIMS mission is to identify the horizontal structures of Transient Luminous Events (TLEs) and spatiotemporal relationship between TLEs and their parent lightning discharges based on the nadir observations from the International Space Station (ISS). For this purpose JEM-GLIMS equips two sets of optical instruments (LSI: CMOS camera, and PH: spectrophotometers) and two sets of radio wave receivers (VLFR: VLF receiver, and VITF: VHF interferometer). As all these instruments are installed at the bottom plane of the bus module facing to the Earth, JEM-GLIMS can carry out the nadir observations continuously. JEM-GLIMS was launched by HTV3 and was successfully installed at the exposed facility of the Japanese Experiment Module (JEM) on August 9, 2012. After the initial checkout operations, JEM-GLIMS finally started continuous observations on November 20, 2012. In the period from November 20, 2012 to June 30, 2013, totally 1597 transient optical events related to lightning flashes and/or TLE emissions were detected by the optical instruments. In 578 of these events, both LSI and PH detected clear transient optical signals well above the noise level. In order to derive sprite events from the detected transient optical events, we analyzed PH light-curve data first and estimated the peak irradiance related to the transient optical flashes. Then, we compared these intensities with the atmospheric transmittance. Finally, LSI image data are examined to clarify the morphological properties of the optical emission. We analyzed a transient optical event detected at 00:56:29.198 UT on December 15, 2012. The peak intensities of PH channels are estimated to be 1.4E-2 W/m2 (150-280 nm), 2.3E-4 W/m2 (316 nm), 5.9E-4 W/m2 (337 nm), 4.0E-4 W/m2 (392 nm), 4.2E-4 W/m2 (762 nm), and 6.3E-2 W/m2 (600-900 nm), respectively. It is found that all these intensities are significantly stronger than the lightning emission affected by the atmospheric transmittance. This fact

  6. Extending the long-term record of volcanic SO2 emissions with the Ozone Mapping and Profiler Suite nadir mapper

    NASA Astrophysics Data System (ADS)

    Carn, S. A.; Yang, K.; Prata, A. J.; Krotkov, N. A.

    2015-02-01

    Uninterrupted, global space-based monitoring of volcanic sulfur dioxide (SO2) emissions is critical for climate modeling and aviation hazard mitigation. We report the first volcanic SO2 measurements using ultraviolet (UV) Ozone Mapping and Profiler Suite (OMPS) nadir mapper data. OMPS was launched on the Suomi National Polar-orbiting Partnership satellite in October 2011. We demonstrate the sensitivity of OMPS SO2 measurements by quantifying SO2 emissions from the modest eruption of Paluweh volcano (Indonesia) in February 2013 and tracking the dispersion of the volcanic SO2 cloud. The OMPS SO2 retrievals are validated using Ozone Monitoring Instrument and Atmospheric Infrared Sounder measurements. The results confirm the ability of OMPS to extend the long-term record of volcanic SO2 emissions based on UV satellite observations. We also show that the Paluweh volcanic SO2 reached the lower stratosphere, further demonstrating the impact of small tropical volcanic eruptions on stratospheric aerosol optical depth and climate.

  7. Multi-Angle Switched HIFU: A New Ultrasound Device for Controlled Non-Invasive Induction of Small Spherical Ablation Zones—Simulation and Ex-Vivo Results

    NASA Astrophysics Data System (ADS)

    Novák, Petr; Jamshidi-Parsian, Azemat; Benson, Donny G.; Webber, Jessica S.; Moros, Eduardo G.; Shafirstein, Gal; Griffin, Robert J.

    2009-04-01

    Current HIFU devices produce elongated elliptical lesions (cigar shaped) in a single energy deposition. This prohibits the effective use of HIFU in small animal research as well as in clinical treatment where small volumes of tissue surrounded by critical structures need to be destroyed. We developed an ultrasound ablation device that non-invasively creates spheroidal lesions of an arbitrary diameter of up to 1 cm in a depth of up to 5 cm. The device consists of two focused ultrasound transducers aimed to the ablation target volume from two directions at a 90 degree angle. The operation of the transducers is switched back and forth so that only one transducer is energized at a time. A transient analysis of this ablation approach was performed using coupled simulations of acoustical pressure distributions, resulting temperature distributions, and thermal dose deposited to soft tissue. A prototype of the device was developed and tested in-vitro in a phantom and later in ex-vivo experiments in pig liver. The experimental results agreed with the numerical simulations and confirmed the ability of the multi-angle switched HIFU (MASH) device to create small spheroidal lesions in soft tissue within 2 minutes without significantly affecting the surrounding tissues.

  8. S-NPP OMPS Nadir In-Flight Performance

    NASA Astrophysics Data System (ADS)

    Pan, S.; Flynn, L. E.; Niu, J.; Grotenhuis, M.; Beck, C. T.; Beach, E.; Zhang, Z.; Tolea, A.

    2014-12-01

    This presentation describes the results of in-flight characterization of the S-NPP Ozone Mapping Profiler Suite (OMPS) charge-coupled device (CCD) performance during the first nearly three years of the OMPS mission in orbit. Data from OMPS's three two-dimension CCD arrays have been collected to characterize in-flight detector behaviors. Our results show that offset, gain, and dark current rate trends remain within sensor requirement limits. System linearity performance trends are stable. The distribution of individual pixel dark rates is slowly growing as expected from pre-launch analyses. The current in-flight dark and linearity calibration corrections provide Sensor Data Records (SDRs) with insignificant error after correction of less than an average of ~0.1% in the Earth radiance retrieval. The instrument optics is less stable than predicted leading to intra-orbit wavelength scale variations as the temperature gradients vary across the instrument. Measurement-based estimates of these effects are as large a ±0.02 nm and are used to make corrections to within +-0.005 nm on a granule by granule basis. Examination of reflectivity, aerosol and ozone EDRs provide evidence of absolute calibration errors with a significant cross track variation. A soft calibration adjustment is under development to remove them.

  9. Reconfiguration of a Nadir-Pointing 2-Craft Coulomb Tether

    NASA Astrophysics Data System (ADS)

    Natarajan, A.; Schaub, H.; Parker, G. G.

    The linear dynamics and stability analysis of reconfiguring a 2-spacecraft Coulomb tether formation is investigated. In this concept the tether between two craft is replaced with electrostatic force fields. Here the relative distance between the two satellites is increased or decreased using electrostatic Coulomb forces. The two craft are connected by an electrostatic tether which is capable of both tensile and compressive forces. The resulting virtual structure can change its shape by modifying the desired reference length. As a result, the two-craft formation will essentially act as a long, slender, nearly-rigid body of variable length. Inter-spacecraft Coulomb forces cannot influence the inertial angular momentum of this formation. However, the gravity gradient effect can be exploited to stabilize the attitude of this Coulomb tether formation about an orbit radial direction. Limits of the Coulomb tether expansion and contraction rates are discussed using linearized time-varying dynamical models. These allow the reference length time histories to be designed while ensuring linear stability of the virtual structure.

  10. Horizontal distributions of sprites derived from the JEM-GLIMS nadir observations

    NASA Astrophysics Data System (ADS)

    Sato, M.; Mihara, M.; Adachi, T.; Ushio, T.; Morimoto, T.; Kikuchi, M.; Kikuchi, H.; Suzuki, M.; Yamazaki, A.; Takahashi, Y.; Inan, U.; Linscott, I.; Ishida, R.; Sakamoto, Y.; Yoshida, K.; Hobara, Y.

    2016-04-01

    Global Lightning and Sprite Measurements on Japanese Experiment Module (JEM-GLIMS) started the nadir observations of lightning discharges and transient luminous events (TLEs) from the International Space Station (ISS) since November 2012. In the nadir observations, JEM-GLIMS optical instruments have to simultaneously detect incomparably intense lightning emissions and weak TLE emissions. To distinguish TLEs, especially sprite events, from lightning events, combined data analytical methods are adopted: (1) a subtraction of the wideband camera image from the narrowband camera image, (2) a calculation of the intensity ratio between different photometer channels, and (3) an estimation of the polarization and charge moment changes for the TLE-producing lightning discharges. We succeeded in identifying numbers of sprite events using the combined analytical methods, and here we report three sprite events detected by JEM-GLIMS as a case study. In the subtracted images, sprite emissions are located over the area of the sprite-producing lightning emissions. However, these sprites and sprite-producing lightning discharges did not occur at the nadir point of the ISS. For this reason, the geometry conversion of the sprite and sprite-producing lightning emissions as observed from the point just over the sprite-producing lightning discharges is performed. In the geometry-converted images, the locations of the sprite emissions are clearly displaced by 8-20 km from the peak positions of the sprite-producing lightning emissions. Thus, the first quantitative spatial distributions of sprites and sprite-producing lightning discharges from the JEM-GLIMS nadir observations are revealed.

  11. Early-stage rifting of the northern Tyrrhenian Sea Basin: Results from a combined wide-angle and multichannel seismic study

    NASA Astrophysics Data System (ADS)

    Moeller, S.; Grevemeyer, I.; Ranero, C. R.; Berndt, C.; Klaeschen, D.; Sallares, V.; Zitellini, N.; Franco, R.

    2013-08-01

    Extension of the continental lithosphere leads to the formation of rift basins and ultimately may create passive continental margins. The mechanisms that operate during the early stage of crustal extension are still intensely debated. We present the results from coincident multichannel seismic and wide-angle seismic profiles that transect across the northern Tyrrhenian Sea Basin. The profiles cross the Corsica Basin (France) to the Latium Margin (Italy) where the early-rift stage of the basin is well preserved. We found two domains, each with a distinct tectonic style, heat flow and crustal thickness. One domain is the Corsica Basin in the west that formed before the main rift phase of the northern Tyrrhenian Sea opening (˜8-4 Ma). The second domain is rifted continental crust characterized by tilted blocks and half-graben structures in the central region and at the Latium Margin. These two domains are separated by a deep (˜10 km) sedimentary complex of the eastern portion of the Corsica Basin. Travel-time tomography of wide-angle seismic data reveals the crustal architecture and a subhorizontal 15-17 ± 1 km deep Moho discontinuity under the basin. To estimate the amount of horizontal extension we have identified the pre-, syn-, and post-tectonic sedimentary units and calculated the relative displacement of faults. We found that major faults initiated at angles of 45°-50° and that the rifted domain is horizontally stretched by a factor of β ˜ 1.3 (˜8-10 mm/a). The crust has been thinned from ˜24 to ˜17 km indicating a similar amount of extension (˜30%). The transect represents one of the best imaged early rifts and implies that the formation of crustal-scale detachments, or long-lived low-angle normal faults, is not a general feature that controls the rift initiation of continental crust. Other young rift basins, like the Gulf of Corinth, the Suez Rift or Lake Baikal, display features resembling the northern Tyrrhenian Basin, suggesting that half

  12. Using Nadir and Directional Emissivity as a Probe of Particle Microphysical Properties

    NASA Astrophysics Data System (ADS)

    Pitman, Karly M.; Wolff, Michael J.; Bandfield, Joshua L.; Clayton, Geoffrey C.

    Real surfaces are not expected to be diffuse emitters, thus observed emissivity values of surface dust deposits are a function of viewing geometry. Attempts to model infrared emission spectral profiles of surface dust deposits at nadir have not yet matured to match the sophistication of astrophysical dust radiative transfer codes. In the absence of strong thermal gradients, directional emissivity may be obtained theoretically via a combination of reciprocity and Kirchhoff's Law. Owing to a lack of laboratory data on directional emissivity for comparison, theorists have not explored the potential utility of directional emissivity as a direct probe of surface dust microphysical properties. Motivated by future analyses of MGS/TES emission phase function (EPF) sequences and the upcoming Mars Exploration Rover mini-TES dataset, we explore the effects of dust particle size and composition on observed radiances at nadir and off-nadir geometries in the TES spectral regime using a combination of multiple scattering radiative transfer and Mie scattering algorithms. Comparisons of these simulated spectra to laboratory spectra of standard mineral assemblages will also be made. This work is supported through NASA grant NAGS-9820 (MJW) and LSU Board of Regents (KMP).

  13. Recall of Nadir CD4 Cell Count and Most Recent HIV Viral Load Among HIV-Infected, Socially Marginalized Adults.

    PubMed

    Buisker, Timothy R; Dufour, Mi-Suk Kang; Myers, Janet J

    2015-11-01

    Lower nadir CD4 cell counts and higher HIV viral loads are associated with increased risks of adverse events in the progression of HIV disease. In cases where medical records are inaccessible or incomplete, little evidence is available regarding whether nadir CDR cell count or HIV viral load is reliably reported in any patient population. We compare survey data collected from 207 HIV-infected individuals detained in San Francisco jails to data collected from electronic medical records (EMR) kept by the jails and community health providers. The sensitivity of self-reported nadir CD4 cell count less than 200 was 82 % [95 % confidence interval (CI) 68, 88], and the sensitivity of reporting an undetectable most recent HIV viral load was 93 % (95 % CI 84, 97). This suggests that in a highly socially marginalized population, nadir CD4 cell count and most recent HIV viral load are recalled accurately when compared to EMR. PMID:25711297

  14. Monitoring regional vegetation change using reflectance measurements from multiple solar zenith angles.

    PubMed

    Russell, M

    2001-09-01

    Many traditional models of vegetation canopy reflectance have commonly used one of two approaches. Either the canopy is assumed to consist of discrete objects of known reflectance and geometric-optics are then used to calculate shading effects, or, as in the turbid medium approach, the canopy is treated as a horizontally homogeneous layer of small elements of known optical properties and radiative transfer theory is used to calculate canopy reflectance. This paper examines the effect of solar zenith angle on the reflectance of red and near-infrared radiation from forests using a combination of these modelling approaches. Forests are first modelled as randomly spaced eucalypt crowns over a homogeneous understorey and the fractional coverage of four components: shaded and sunlit canopy and shaded and sunlit understorey are calculated. Reflectance from each fraction is then modelled for a range of solar zenith angles using the Verhoef SAIL model. The overall scene reflection as seen by a nadir viewing satellite sensor is compared for three forest types representing a gradient of crown density from open dry grassy woodlands to dense wetter closed forest with an understorey of mesophytic plants. Modelled trends in scene reflectance change are consistent with aircraft measurements carried out at three different solar zenith angles. Results indicate that an increase in both tree density and solar zenith angle leads to an increase in the dominance of shaded components. In the visible band, both the sparsely treed woodland and the medium density dry forest show similar trends to that predicted by a turbid medium model, however, the wet forest shows a less rapid decrease in reflectance with solar zenith angle. In the near-infrared band, as tree density increases from woodland to wet forest, overall scene reflectance shows increased departure from that modelled using the traditional assumption of smooth homogeneous canopies, changing from an increase with solar zenith angle

  15. Preliminary results for a large angle oblique jet impingement and flow and for the effect of initial conditions on the near field of an axisymmetric jet

    NASA Technical Reports Server (NTRS)

    Foss, J. F.; Kleis, S. J.

    1973-01-01

    The structure of an axisymmetric jet in the near field is discussed for jet noise and for jet impingment schemes for STOL aircraft. It is inferred from previous studies, and the inference is supported by analysis, that the scale and intensity of the turbulence structure at the jet exit plane are the important boundary conditions which effect the development of the flow in the near field. The techniques to study these effects while maintaining a uniform mean flow and the results which document the range of the initial conditions are presented. The large angle, oblique jet impingment condition is of interest in terms of the jet/flap interaction. Detailed turbulence data can be obtained with the specially constructed facility. The development of the flow and instrumentation system and initial data from the new facility are presented.

  16. Equivalent Biochemical Control and Improved Prostate-Specific Antigen Nadir After Permanent Prostate Seed Implant Brachytherapy Versus High-Dose Three-Dimensional Conformal Radiotherapy and High-Dose Conformal Proton Beam Radiotherapy Boost

    SciTech Connect

    Jabbari, Siavash; Weinberg, Vivian K.; Shinohara, Katsuto; Speight, Joycelyn L.; Gottschalk, Alexander R.; Hsu, I.-C.; Pickett, Barby; McLaughlin, Patrick W.; Sandler, Howard M.; Roach, Mack

    2010-01-15

    Purpose: Permanent prostate implant brachytherapy (PPI), three-dimensional conformal radiotherapy (3D-CRT), and conformal proton beam radiotherapy (CPBRT) are used in the treatment of localized prostate cancer, although no head-to-head trials have compared these modalities. We studied the biochemical control (biochemical no evidence of disease [bNED]) and prostate-specific antigen (PSA) nadir achieved with contemporary PPI, and evaluated it against 3D-CRT and CPBRT. Patients and Methods: A total of 249 patients were treated with PPI at the University of California, San Francisco, and the outcomes were compared with those from a 3D-CRT cohort and the published results of a high-dose CPBRT boost (CPBRTB) trial. For each comparison, subsets of the PPI cohort were selected with patient and disease criteria similar to those of the reference group. Results: With a median follow-up of 5.3 years, the bNED rate at 5 and 7 years achieved with PPI was 92% and 86%, respectively, using the American Society for Therapeutic Radiology and Oncology (ASTRO) definition, and 93% using the PSA nadir plus 2 ng/mL definition. Using the ASTRO definition, a 5-year bNED rate of 78% was achieved for the 3D-CRT patients compared with 94% for a comparable PPI subset and 93% vs. 92%, respectively, using the PSA nadir plus 2 ng/mL definition. The median PSA nadir for patients treated with PPI and 3D-CRT was 0.10 and 0.40 ng/mL, respectively (p < .0001). For the CPBRT comparison, the 5-year bNED rate after a CPBRTB was 91% using the ASTRO definition vs. 93% for a similar group of PPI patients. A greater proportion of PPI patients achieved a lower PSA nadir compared with those achieved in the CPBRTB trial (PSA nadir <=0.5 ng/mL, 91% vs. 59%, respectively). Conclusion: We have demonstrated excellent outcomes in low- to intermediate-risk patients treated with PPI, suggesting at least equivalent 5-year bNED rates and a greater proportion of men achieving lower PSA nadirs compared with 3D-CRT or

  17. Angle detector

    NASA Technical Reports Server (NTRS)

    Parra, G. T. (Inventor)

    1978-01-01

    An angle detector for determining a transducer's angular disposition to a capacitive pickup element is described. The transducer comprises a pendulum mounted inductive element moving past the capacitive pickup element. The capacitive pickup element divides the inductive element into two parts L sub 1 and L sub 2 which form the arms of one side of an a-c bridge. Two networks R sub 1 and R sub 2 having a plurality of binary weighted resistors and an equal number of digitally controlled switches for removing resistors from the networks form the arms of the other side of the a-c bridge. A binary counter, controlled by a phase detector, balances the bridge by adjusting the resistance of R sub 1 and R sub 2. The binary output of the counter is representative of the angle.

  18. EP3/FP dual receptor agonist ONO-9054 administered morning or evening to patients with open-angle glaucoma or ocular hypertension: results of a randomised crossover study

    PubMed Central

    Berlin, Michael S; Rowe-Rendleman, Cheryl; Ahmed, Ike; Ross, Douglas T; Fujii, Akifumi; Ouchi, Takafumi; Quach, Christine; Wood, Andrew; Ward, Caroline L

    2016-01-01

    Background/aims The novel prostaglandin E (EP) 3 and prostaglandin F (FP) receptor agonist ONO-9054 is effective in lowering intraocular pressure (IOP) in patients with ocular hypertension and open-angle glaucoma when administered once daily. This study compares the effects of morning (AM) versus evening (PM) dosing of ONO-9054 on tolerability and IOP lowering. Methods This was a single-centre, randomised, double-masked, two-sequence, placebo-controlled crossover study in 12 subjects with bilateral primary open-angle glaucoma or ocular hypertension. Two 14-day crossover regimens were separated by a 2-week washout: ONO-9054 (1 drop to each eye) in the morning (07:00) and vehicle in the evening (19:00) and vice versa. IOP was measured multiple times during select days. Ocular examinations also evaluated safety and tolerability. Results Mild ocular hyperaemia, reported by six subjects with PM dosing, was the most frequent adverse event. Mild to moderate dryness was also slightly more frequent after PM dosing. Maximum IOP reduction from baseline occurred on day 2 with decreases from baseline of −7.4 mm Hg (−30.8%) for AM dosing and −9.1 mm Hg, (−38.0%) for PM dosing; after 14 days, mean reduction in IOP was −6.8 mm Hg (−28.6%) for AM dosing and −7.5 mm Hg (−31.0%) for PM dosing. Conclusions PM dosing of ONO-0954 was associated with a slightly increased frequency of mild hyperaemia and mild to moderate dryness. Both dosing schedules provided sustained reduction in IOP. Trial registration number NCT01670266. PMID:26453641

  19. Assessment of the stratospheric NO2 column using long-term ground-based UV-visible and satellite nadir observations

    NASA Astrophysics Data System (ADS)

    Pinardi, Gaia; Van Roozendael, Michel; Lambert, Jean-Christopher; Hendrick, Francois; Granville, José; Tack, Frederik; Goutail, Florence; Pommereau, Jean-Pierre; Pazmino, Andrea; Wittrock, Folkard; Richter, Andreas; Wagner, Thomas; Gu, Myojeong; Friess, Udo; Navarro, Monica; Puentedura, Olga

    2015-04-01

    Zenith-sky UV-visible instruments have been used to monitor stratospheric NO2 columns from pole to pole for more than 2 decades, as part of the Network for the Detection of Atmospheric Composition Change (NDACC). Long-term monitoring and fit-for-purpose data quality are essential commitments of the network. Recently, recommendations were made for a better harmonization of the retrieval of NO2 stratospheric vertical columns (Van Roozendael and Hendrick 2012, http://ndacc-uvvis-wg.aeronomie.be/tools/NDACC_UVVIS-WG_NO2settings_v4.pdf). Those include, in addition to the use of harmonized SCD settings, a common approach to the air-mass factor (AMF) calculation, based on pre-calculated look-up tables of climatological AMFs resolved in latitude, time, wavelength, surface albedo, solar zenith angle and station altitude. The impact of the NDACC recommendations on the quality of the zenith-sky UV-visible stratospheric NO2 columns is first illustrated based on 10 SAOZ (Système d'Analyse par Observations Zénithales) instruments deployed from the Arctic to the Antarctic. The long-term time-series of SAOZ and other ground-based NDACC zenith-sky measurements are then used in synergy with data from an ensemble of satellite UV-vis nadir sensors (GOME-2, SCIAMACHY and OMI), for characterising the stratospheric NO2 columns on the global scale. Appropriate photochemical state matching is applied whenever necessary to combine/compare the different data sets. Results are interpreted in terms of ground-based network data homogeneity, and accuracy, consistency and long-term stability of space-borne stratospheric NO2 columns. The consistency with previously published studies including stratospheric NO2 column measurements from limb sensors such as MIPAS and SCIAMACHY is also discussed. These quality-assessed ground-based and satellite data sets offer new perspectives for the analysis of the variability and trends of stratospheric NO2 at the global scale.

  20. Aerosol Optical Depth Model Assessment With High-Resolution Multiple Angle Sensors

    NASA Astrophysics Data System (ADS)

    Martin, J. S.; Nielsen, K. E.; Vincent, D. A.; Durkee, P. A.; Reid, J. S.

    2005-12-01

    The Naval Postgraduate School Aerosol Optical Depth (NPS AOD) model has been used successfully to retrieve aerosol optical depths over water using Advanced Very High Resolution Radiometer (AVHRR) imagery. In this work, the NPS AOD model is applied to the QuickBird high-resolution commercial satellite imagery collected at multiple zenith angles around Sir Bu Nuair Island, United Arab Emirates in September 2004 during the Unified Aerosol Experiment, United Arab Emirates (UAE2) Campaign. The QuickBird-retrieved aerosol optical depths are compared to other satellite and ground-based optical depth retrievals, including those from the Aeerosol Robotic NETwork (AERONET), the MODerate resolution Imaging Spectroradiometer (MODIS), Multi-angle Imaging Spectroradiometer (MISR), and AVHRR. Adapting the NPS AOD model to the nominally 2.4-meter resolution imagery from QuickBird required using modal radiances determined over an area that matched the lower resolution imagers (~ 275 meters to 1 kilometer). Additionally, the NPS AOD model was originally developed for the AVHRR imager on the NOAA-14 satellite. The NPS AOD model selects a modeled aerosol size distribution and scattering phase function based on the ratio the red and near-infrared channels of the AVHRR and the scattering angle derived from solar-sensor geometry. As such, the LUT that relates the ratio of red and near-infrared radiances was based on the center effective wavelengths of the NOAA-14 channels. The AOD retrievals from the other imagers must be adjusted to account for the changes in center effective wavelengths of the red and near-IR channels. Results show that the application of the NPS AOD model to QuickBird data yields findings that are consistent with other satellite and ground-based retrievals. In general, the NPS AOD model works well for nadir and near-nadir view angles, but not for zenith angles greater than 50 degrees. A non-linearized single scattering model and additional scattering streams will be

  1. Preliminary Results on the Mechanics of the Active Mai'iu Low Angle Normal Fault (Dayman Dome), Woodlark Rift, SE Papua New Guinea

    NASA Astrophysics Data System (ADS)

    Little, T. A.; Boulton, C. J.; Mizera, M.; Webber, S. M.; Oesterle, J.; Ellis, S. M.; Norton, K. P.; Wallace, L. M.; Biemiller, J.

    2015-12-01

    Rapid slip on the Mai'iu low-angle normal fault (LANF) has exhumed a smooth, corrugated fault surface contiguous for >24 km up-dip, rising from near sea level to ~2900 m. The fault emerges from the ground dipping ~21° N and flattens over the crest of the dome to dip south. Geomorphic analysis reveals a progressive back-tilting of the surface during exhumation accompanied by cross-cutting antithetic-sense high-angle faults—features that we attribute to "rolling-hinge" deformation of a once more steeply-dipping fault. Near the scarp base, the footwall exposes mafic mylonites that deformed at ~400-450°C. The younger Mai'iu fault cross-cuts this ductile mylonite zone, with most brittle slip being localized into a ~20 cm-thick, gouge-filled core. Near the range front, active faults bite across both the hangingwall and footwall of the Mai'iu fault and record overprinting across a dying, shallow (<~1 km deep) part of the fault by more optimally oriented, steeper faults. Such depth-dependent locking up of the fault suggests it weakens primarily by friction reduction rather than cohesion loss. Outcrop-scale fractures in the exhumed footwall reflect formation in an Andersonian stress regime. Previous campaign GPS data suggest the fault slips at up to ~1 cm/yr. To improve resolution and test for aseismic creep, we installed 12 GPS sites across the fault trace in 2015. Quantitative XRD indicates the gouges were derived primarily from mafic footwall, containing up to 65% corrensite and saponite. Hydrothermal friction experiments on two gouges from a relict LANF strand were done at varying normal stresses (30-120 MPa), temperatures (50-200oC), and sliding velocities (0.3-100 μm/s). Results reveal very weak frictional strength (μ=0.13-0.15 and 0.20-0.28) and velocity-strengthening behavior conducive to fault creep. At the highest temperatures (T≥150oC) and lowest sliding velocities (<3 μm/s), a transition to velocity-weakening behavior indicates the potential for

  2. Results of a study of Mach number and Reynolds number effects on the lee side vortex flow field characteristics of an ogive-cylinder-frustum-cylinder at angles of attack to 25 degrees, volume 1

    NASA Technical Reports Server (NTRS)

    Foley, J. E.

    1972-01-01

    An experimental program was conducted to survey the lee side vortex flow field about an ogive-cylinder-frustum-cylinder at angles of attack to 25 degrees for two Reynolds numbers at Mach number 0.8, and one Reynolds number at Mach number 1.96. The data were obtained using miniature 5-port conical pressure probes calibrated for angle of attack and roll angle over a Mach number range of 0.6 to 3.0. The results are presented here as local flow field properties and circulation strengths for various body stations.

  3. P-wave velocity structure of the southern Ryukyu margin east of Taiwan: Results from the ACTS wide-angle seismic experiment

    NASA Astrophysics Data System (ADS)

    Klingelhoefer, F.; Berthet, T.; Lallemand, S.; Schnurle, P.; Lee, C.-S.; Liu, C.-S.; McIntosh, K.; Theunissen, T.

    2012-11-01

    An active seismic experiment has been conducted across the southern Ryukyu margin east of Taiwan over the whole trench-arc-backarc system in May 2009. Twenty-four ocean bottom seismometers (OBS) were deployed from the Ryukyu trench to the southern Okinawa trough over the Ryukyu arc and forearc. Wide angle seismic data were recorded by the OBS array while coincident reflection seismic data were acquired using a 6 km long streamer and a 6600 cubic inch seismic airgun array. Results from tomographic inversion of 21091 travel time picks along this line allowed us to image crustal structures of the Ryukyu margin down to a depth of 25 km. The transect has been designed to provide a better seismic velocity structure of the subduction zone in a highly deformed area that has produced an M8 earthquake in 1920. The line crosses a seismic cluster of earthquakes which source mechanisms are still poorly understood. The subducting oceanic crust of the Huatung Basin is about 5-6 km thick. The underlying mantle exhibits low seismic velocities around 7.8 km/s suggesting some hydrothermal alterations or alteration of the upper mantle through faults generated by the flexure of the subducting plate as it enters the subduction. Low velocities, up to 4.5 km/s, associated with the accretionary wedge are well imaged from the trench back to the Nanao forearc. A major result concerns the abrupt termination of the buttress at the rear of the accretionary wedge. Despite the low resolution of the tomographic inversion near the subduction interface, several lines of evidence supporting the presence of a low velocity zone beneath the toe of the forearc buttress could be established. The Moho beneath the Ryukyu non-volcanic arc is located at a depth around 25 km depth.

  4. Sun-view angle effects on reflectance factors of corn canopies

    NASA Technical Reports Server (NTRS)

    Ranson, K. J.; Daughtry, C. S. T.; Biehl, L. L.; Bauer, M. E.

    1985-01-01

    The effects of sun and view angles on reflectance factors of corn (Zea mays L.) canopies ranging from the six leaf stage to harvest maturity were studied on the Purdue University Agronomy Farm by a multiband radiometer. The two methods of acquiring spectral data, the truck system and the tower systrem, are described. The analysis of the spectral data is presented in three parts: solar angle effects on reflectance factors viewed at nadir; solar angle effects on reflectance factors viewed at a fixed sun angle; and both sun and view angles effect on reflectance factors. The analysis revealed that for nadir-viewed reflectance factors there is a strong solar angle dependence in all spectral bands for canopies with low leaf area index. Reflectance factors observed from the sun angle at different view azimuth angles showed that the position of the sensor relative to the sun is important in determining angular reflectance characteristics. For both sun and view angles, reflectance factors are maximized when the sensor view direction is towards the sun.

  5. Relative and Absolute Calibration of a Multihead Camera System with Oblique and Nadir Looking Cameras for a Uas

    NASA Astrophysics Data System (ADS)

    Niemeyer, F.; Schima, R.; Grenzdörffer, G.

    2013-08-01

    Numerous unmanned aerial systems (UAS) are currently flooding the market. For the most diverse applications UAVs are special designed and used. Micro and mini UAS (maximum take-off weight up to 5 kg) are of particular interest, because legal restrictions are still manageable but also the payload capacities are sufficient for many imaging sensors. Currently a camera system with four oblique and one nadir looking cameras is under development at the Chair for Geodesy and Geoinformatics. The so-called "Four Vision" camera system was successfully built and tested in the air. A MD4-1000 UAS from microdrones is used as a carrier system. Light weight industrial cameras are used and controlled by a central computer. For further photogrammetric image processing, each individual camera, as well as all the cameras together have to be calibrated. This paper focuses on the determination of the relative orientation between the cameras with the „Australis" software and will give an overview of the results and experiences of test flights.

  6. Retrieval of CO from nadir remote-sensing measurements in the infrared by use of four different inversion algorithms.

    PubMed

    Clerbaux, Cathy; Hadji-Lazaro, Juliette; Payan, Sébastien; Camy-Peyret, Claude; Wang, Jinxue; Edwards, David P; Luo, Ming

    2002-11-20

    Four inversion schemes based on various retrieval approaches (digital gas correlation, nonlinear least squares, global fit adjustment, and neural networks) developed to retrieve CO from nadir radiances measured by such downward-looking satelliteborne instruments as the Measurement of Pollution in the Troposphere (MOPITT), the Tropospheric Emission Spectrometer (TES), and the Infrared Atmospheric Sounding Interferometer (IASI) instruments were compared both for simulated cases and for atmospheric spectra recorded by the Interferometric Monitor for Greenhouse Gases (IMG). The sensitivity of the retrieved CO total column amount to properties that may affect the inversion accuracy (noise, ancillary temperature profile, and water-vapor content) was investigated. The CO column amounts for the simulated radiance spectra agreed within 4%, whereas larger discrepancies were obtained when atmospheric spectra recorded by the IMG instrument were analyzed. The assumed vertical temperature profile is shown to be a critical parameter for accurate CO retrieval. The instrument's line shape was also identified as a possible cause of disagreement among the result provided by the groups of scientist who are participating in this study. PMID:12463254

  7. Seismic Refraction & Wide-angle Reflection Experiment on the Northern Margin of North China Craton -Data Acquisition and Preliminary Processing Result

    NASA Astrophysics Data System (ADS)

    Li, W.; Gao, R.; Keller, G. R.; Hou, H.; Li, Q.; Cox, C. M.; Chang, J. C.; Zhang, J.; Guan, Y.

    2010-12-01

    The evolution history of Central Asian Orogen Belt (CAOB) is still the main tectonic problems in northeastern Asia. The Siberia Craton (NC), North China Craton (NCC) and several blocks collided, and the resulting tectonic collage formed as the Paleo-Asian Ocean disappeared. Concerning the northern margin of North China Craton, many different geological questions remain unanswered, such as: the intracontinental orogenic process in the Yanshan orogen and the nature and location of the suture between the southern NC and the northern NCC. In Dec 2009, a 400 km long seismic refraction and wide-angle reflection profile was completed jointly by Institute of Geology, CAGS and University of Oklahoma. The survey line extended from the west end of the Yanshan orogen, across a granitoid belt to the Solonker suture zone. The recording of seismic waves from 8 explosions (500~1500 kg each) was conducted in four deployments of 300 Reftek125 (Texan) seismic recorders, with an average spacing of 1 km. For the calculations, we used the Rayinvr, Vmed and Zplot programs for ray tracing, model modification and phase picking. The initial result show that: 1)the depth of low velocity sediment cover ranges from 0.6 to 2.7 km (velocity: 2.8~5.6 km/s); 2)the depth of basement is 5.6~10 km (the depth of basement under the granitoid belt deepens to 10 km and velocity increases to 6.2 km/s); 3)the upper crust extends to a depth of 15.5~21 km and has the P-wave velocities between 5.6 and 6.4 km/s; 4)the thickness of the lower crust ranges from 22~28 km(velocity: 6.4~6.9 km/s); and 5)the depth of Moho varies from 39.5 km under the granitoid belt to 49 km under the Yanshan orogen. Based on these results, we can preliminarily deduce that: 1) the concave depression of the Moho observed represents the root of the Yanshan orogen, and it may prove that the orogen is dominated by thick-skinned tectonics; 2) the shape of velocity variations under the granitoid belt is suggestive of a magma conduit. It

  8. Angle performance on optima MDxt

    SciTech Connect

    David, Jonathan; Kamenitsa, Dennis

    2012-11-06

    Angle control on medium current implanters is important due to the high angle-sensitivity of typical medium current implants, such as halo implants. On the Optima MDxt, beam-to-wafer angles are controlled in both the horizontal and vertical directions. In the horizontal direction, the beam angle is measured through six narrow slits, and any angle adjustment is made by electrostatically steering the beam, while cross-wafer beam parallelism is adjusted by changing the focus of the electrostatic parallelizing lens (P-lens). In the vertical direction, the beam angle is measured through a high aspect ratio mask, and any angle adjustment is made by slightly tilting the wafer platen prior to implant. A variety of tests were run to measure the accuracy and repeatability of Optima MDxt's angle control. SIMS profiles of a high energy, channeling sensitive condition show both the cross-wafer angle uniformity, along with the small-angle resolution of the system. Angle repeatability was quantified by running a channeling sensitive implant as a regular monitor over a seven month period and measuring the sheet resistance-to-angle sensitivity. Even though crystal cut error was not controlled for in this case, when attributing all Rs variation to angle changes, the overall angle repeatability was measured as 0.16 Degree-Sign (1{sigma}). A separate angle repeatability test involved running a series of V-curves tests over a four month period using low crystal cut wafers selected from the same boule. The results of this test showed the angle repeatability to be <0.1 Degree-Sign (1{sigma}).

  9. The inference of atmospheric ozone using satellite nadir measurements in the 1042/cm band

    NASA Technical Reports Server (NTRS)

    Russell, J. M., III; Drayson, S. R.

    1973-01-01

    A description and detailed analysis of a technique for inferring atmospheric ozone information from satellite nadir measurements in the 1042 cm band are presented. A method is formulated for computing the emission from the lower boundary under the satellite which circumvents the difficult analytical problems caused by the presence of atmospheric clouds and the watervapor continuum absorption. The inversion equations are expanded in terms of the eigenvectors and eigenvalues of a least-squares-solution matrix, and an analysis is performed to determine the information content of the radiance measurements. Under favorable conditions there are only two pieces of independent information available from the measurements: (1) the total ozone and (2) the altitude of the primary maximum in the ozone profile.

  10. Results from 1984 airborne Doppler lidar wind measurement program. Flight 6: Analysis of line-of-sight elevation angle errors and apparent Doppler velocities

    NASA Technical Reports Server (NTRS)

    Rothermel, Jeffry

    1987-01-01

    During the summer of 1984 the Marshall Space Flight Center's Airborne Doppler Lidar System (ADLS) made a series of wind measurements in the California Central Valley. This study quantifies the lidar beam angle errors and velocity errors through analysis of ground return signals. Line-of-sight elevation (LOSE) angle errors are under 1 deg. Apparent Doppler ground velocities, as large as 2m/s, are considerably less than in a previous flight experiment in 1981. No evidence was found of a Schuler resonance phenomenon common to inertial navigation systems (INS), however the aperiodic nature of the apparent velocities implies an error in the INS-derived ground speeds. Certain features and subtleties in the ground returns are explained in terms of atmospheric structure and characteristics of the ADLS hardware and software. Finally, least squares and low-pass filtering techniques are suggested for eliminating errors during post-processing.

  11. Some results of investigations conducted in the interplanetary medium using the wide-angle plasma detectors on the Prognoz-6 spacecraft

    NASA Astrophysics Data System (ADS)

    Verigin, M. I.

    Measurements of the ion and electron components of plasma in the magnetic field and energetic particle fluxes in interplanetary space were obtained using a wide-angle plasma detector. The effect of two solar-flare events in November 1977 and January 1978 on the energetic characteristics of interplanetary space was analyzed on the basis of the plasma measurements. It is found that protons can be accelerated to energies of several MeV in oblique shock waves.

  12. Retrieval and monitoring of atmospheric trace gas concentrations in nadir and limb geometry using the space-borne SCIAMACHY instrument.

    PubMed

    Sierk, B; Richter, A; Rozanov, A; Von Savigny, Ch; Schmoltner, A M; Buchwitz, M; Bovensmann, H; Burrows, J P

    2006-09-01

    The Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) onboard the European Envisat spacecraft performs continuous spectral observations of reflected, scattered and transmitted sunlight in various observation geometries. A unique feature of SCIAMACHY is the capability of probing the atmosphere in three different observation geometries:The nadir, limb, and occultation measurement modes. In nadir mode, column densities of trace gases are retrieved with a spatial resolution of typically 30 x 60 km using the Differential Optical Absorption Spectroscopy (DOAS) technique (Platt and Perner, 1983). Alternating with the nadir measurement, vertical profiles of absorber concentration in the stratosphere are derived in limb and occultation. In this paper we present an overview over some applications of SCIAMACHY data in space-based monitoring of atmospheric pollution. The DOAS algorithms for the retrieval of total column amounts from nadir spectra are briefly described and case studies of pollution events are presented. We also illustrate the technique used to derive stratospheric concentration profiles from limb observations and show comparisons with other remote sensing systems. Special emphasis will be given to techniques, which take advantage of SCIAMACHY's different viewing geometries. In particular, we will discuss the potential and limits of strategies to infer tropospheric abundances of O3 and NO2. PMID:16715354

  13. Wide angle X-ray scattering (WAXS) study of "two-line" ferrihydrite structure: Effect of arsenate sorption and counterion variation and comparison with EXAFS results

    USGS Publications Warehouse

    Waychunas, G.A.; Fuller, C.C.; Rea, B.A.; Davis, J.A.

    1996-01-01

    Wide angle X-ray scattering (WAXS) measurements have been made on a suite of "two-line" ferrihydrite (FHY2) samples containing varying amounts of coprecipitated arsenate. Samples prepared at pH 8 with counter ions chloride, nitrate, and a mixture of both also were examined. The raw WAXS scattering functions show that "two-line" ferrihydrite actually has a large number of non-Bragg (i.e., diffuse scattering) maxima up to our observation limit of 16 A??-1. The type of counter ion used during synthesis produces no significant change in this function. In unarsenated samples, Radial Distribution Functions (RDFs) produced from the scattering functions show a well-defined Fe-O peak at 2.02 A?? in excellent agreement with the mean distance of 2.01 A?? from extended X-ray absorption fine structure (EXAFS) analysis. The area under the Fe-O peak is consistent with only octahedral oxygen coordination about iron, and an iron coordination about oxygen of 2.2, in agreement with the EXAFS results, the sample composition, and XANES measurements. The second peak observed in the RDFs is clearly divided into two populations of correlations, at 3.07 and 3.52 A??, respectively. These distances are close to the EXAFS-derived Fe-Fe subshell distances of 3.02-3.05 and 3.43-3.46 A??, respectively, though this is misleading as the RDF peaks also include contributions from O-Fe and O-O correlations. Simulated RDFs of the FeOOH polymorphs indicate how the observed RDF structure relates to the EXAFS pair-correlation function, and allow comparisons with an ordered ferrihydrite structure. The effect of increasing arsenate content is dramatic, as the RDF peaks are progressively smeared out, indicating a wider range of interatomic distances even at moderate surface coverages, and a loss of longer range correlations. At an As/Fe ratio of 0.68, the surface saturation level of arsenate, the RDF shows little order beyond what would be expected from small pieces of dioctahedral Fe oxyhydroxyl chains or

  14. Detection Method of Lightning and TLEs by JEM-GLIMS Nadir Observation

    NASA Astrophysics Data System (ADS)

    Adachi, T.; Sato, M.; Ushio, T.; Yamazaki, A.; Suzuki, M.; Masayuki, K.; Takahashi, Y.; Inan, U.; Linscott, I.; Hobara, Y.

    2013-12-01

    A scientific payload named JEM-GLIMS aboard the International Space Station (ISS) is aimed at observing lightning and Transient Luminous Events (TLEs) globally. Keeping its field-of-view toward the nadir direction, GLIMS clarifies the horizontal structures of lightning and TLEs, which is a crucial issue to understand the electrodynamic coupling between the troposphere and ionosphere. A difficult point, however, is that careful analyses are necessary to separate the emissions of lightning and TLEs which spatially overlap along the line-of-sights in the case of nadir observation. In this study, we analyze the multi-wavelength optical data obtained by GLIMS to identify lightning and TLEs. The main data analyzed are those of imager (LSI) and spectrophotometer (PH). LSI consists of two cameras equipped with a broadband red filter and a narrowband 762-nm filter, respectively, and obtains imagery at a spatial resolution of 400 m/pixel on the ground surface. PH detects time-resolved emission intensity at a sampling rate of 20 kHz by six photometer channels measuring at 150-280, 337, 762, 600-900, 316 and 392 nm, respectively. During a period between November 2012 and June 2013, GLIMS observed 815 lightning and/or TLE events, and in 494 of them, both LSI and PH data showed clear signals above the noise level. As the first step, we carried out case study using an event observed at 09:50:47UT on Jan 29 2013 which did not cause strong saturation on the LSI and PH data. The estimated peak irradiance was 1.38x10^(-3) W/m^(2) at 600-900 nm, which is equivalent to the top 10 % bright lightning events observed by FORTE satellite in the past. This finding suggests that GLIMS selectively observes the most optically-powerful events. The peak irradiance was estimated also for the other PH channels. At all visible channels other than a far ultra violet (FUV) channel, the peak irradiance was estimated to be in good agreement with the atmospheric transmittance curve calculated between 10

  15. Utility of BRDF Models for Estimating Optimal View Angles in Classification of Remotely Sensed Images

    NASA Technical Reports Server (NTRS)

    Valdez, P. F.; Donohoe, G. W.

    1997-01-01

    Statistical classification of remotely sensed images attempts to discriminate between surface cover types on the basis of the spectral response recorded by a sensor. It is well known that surfaces reflect incident radiation as a function of wavelength producing a spectral signature specific to the material under investigation. Multispectral and hyperspectral sensors sample the spectral response over tens and even hundreds of wavelength bands to capture the variation of spectral response with wavelength. Classification algorithms then exploit these differences in spectral response to distinguish between materials of interest. Sensors of this type, however, collect detailed spectral information from one direction (usually nadir); consequently, do not consider the directional nature of reflectance potentially detectable at different sensor view angles. Improvements in sensor technology have resulted in remote sensing platforms capable of detecting reflected energy across wavelengths (spectral signatures) and from multiple view angles (angular signatures) in the fore and aft directions. Sensors of this type include: the moderate resolution imaging spectroradiometer (MODIS), the multiangle imaging spectroradiometer (MISR), and the airborne solid-state array spectroradiometer (ASAS). A goal of this paper, then, is to explore the utility of Bidirectional Reflectance Distribution Function (BRDF) models in the selection of optimal view angles for the classification of remotely sensed images by employing a strategy of searching for the maximum difference between surface BRDFs. After a brief discussion of directional reflect ante in Section 2, attention is directed to the Beard-Maxwell BRDF model and its use in predicting the bidirectional reflectance of a surface. The selection of optimal viewing angles is addressed in Section 3, followed by conclusions and future work in Section 4.

  16. Characteristics of Deep Tropical and Subtropical Convection from Nadir-Viewing High-Altitude Airborne Doppler Radar

    NASA Technical Reports Server (NTRS)

    Heymsfield, Gerald M.; Tian, Lin; Heymsfield, Andrew J.; Li, Lihua; Guimond, Stephen

    2010-01-01

    This paper presents observations of deep convection characteristics in the tropics and subtropics that have been classified into four categories: tropical cyclone, oceanic, land, and sea breeze. Vertical velocities in the convection were derived from Doppler radar measurements collected during several NASA field experiments from the nadir-viewing high-altitude ER-2 Doppler radar (EDOP). Emphasis is placed on the vertical structure of the convection from the surface to cloud top (sometimes reaching 18-km altitude). This unique look at convection is not possible from other approaches such as ground-based or lower-altitude airborne scanning radars. The vertical motions from the radar measurements are derived using new relationships between radar reflectivity and hydrometeor fall speed. Various convective properties, such as the peak updraft and downdraft velocities and their corresponding altitude, heights of reflectivity levels, and widths of reflectivity cores, are estimated. The most significant findings are the following: 1) strong updrafts that mostly exceed 15 m/s, with a few exceeding 30 m/s, are found in all the deep convection cases, whether over land or ocean; 2) peak updrafts were almost always above the 10-km level and, in the case of tropical cyclones, were closer to the 12-km level; and 3) land-based and sea-breeze convection had higher reflectivities and wider convective cores than oceanic and tropical cyclone convection. In addition, the high-resolution EDOP data were used to examine the connection between reflectivity and vertical velocity, for which only weak linear relationships were found. The results are discussed in terms of dynamical and microphysical implications for numerical models and future remote sensors.

  17. Generalization of the Euler Angles

    NASA Technical Reports Server (NTRS)

    Bauer, Frank H. (Technical Monitor); Shuster, Malcolm D.; Markley, F. Landis

    2002-01-01

    It is shown that the Euler angles can be generalized to axes other than members of an orthonormal triad. As first shown by Davenport, the three generalized Euler axes, hereafter: Davenport axes, must still satisfy the constraint that the first two and the last two axes be mutually perpendicular if these axes are to define a universal set of attitude parameters. Expressions are given which relate the generalized Euler angles, hereafter: Davenport angles, to the 3-1-3 Euler angles of an associated direction-cosine matrix. The computation of the Davenport angles from the attitude matrix and their kinematic equation are presented. The present work offers a more direct development of the Davenport angles than Davenport's original publication and offers additional results.

  18. The feasibility of retrieving vertical temperature profiles from satellite nadir UV observations: A sensitivity analysis and an inversion experiment with neural network algorithms

    NASA Astrophysics Data System (ADS)

    Sellitto, P.; Del Frate, F.

    2014-07-01

    Atmospheric temperature profiles are inferred from passive satellite instruments, using thermal infrared or microwave observations. Here we investigate on the feasibility of the retrieval of height resolved temperature information in the ultraviolet spectral region. The temperature dependence of the absorption cross sections of ozone in the Huggins band, in particular in the interval 320-325 nm, is exploited. We carried out a sensitivity analysis and demonstrated that a non-negligible information on the temperature profile can be extracted from this small band. Starting from these results, we developed a neural network inversion algorithm, trained and tested with simulated nadir EnviSat-SCIAMACHY ultraviolet observations. The algorithm is able to retrieve the temperature profile with root mean square errors and biases comparable to existing retrieval schemes that use thermal infrared or microwave observations. This demonstrates, for the first time, the feasibility of temperature profiles retrieval from space-borne instruments operating in the ultraviolet.

  19. Towards a NNORSY Ozone Profile ECV from European Nadir UV/VIS Measurements

    NASA Astrophysics Data System (ADS)

    Felder, Martin; Kaifel, Anton; Huckle, Roger

    2010-12-01

    The Neural Network Ozone Retrieval System (NNORSY) has been adapted and applied to several different satellite instruments, including the backscatter UV/VIS instruments ERS2-GOME, SCIAMACHY and METOP-GOME-2. The retrieved long term ozone field hence spans the years 1995 till now. To provide target data for training the neural networks, the lower parts of the atmosphere are sampled by ozone sondes from the WOUDC and SHADOZ data archives. Higher altitudes are covered by a variety of limb-sounding instruments, including the SAGE and POAM series, HALOE, ACE-FTS and AURA-MLS. In this paper, we show ozone profile time series over the entire time range to demonstrate the "out-of-the-box" consistency and homogeneity of our data across the three different nadir sounders, i.e. without any kind of tuning applied. These features of Essential Climate Variable (ECV) datasets [1] also lie at the heart of the recently announced ESA Climate Change Initiative, to which we hope to contribute in the near future.

  20. AIRS and Full-Resolution CrIS: Comparison Using Tropical Simultaneous Nadir Observations

    NASA Astrophysics Data System (ADS)

    Aumann, H. H.; Manning, E. M.

    2015-12-01

    AIRS on EOS-Aqua and CrIS on Suomi NPP are two hyperspectral infrared sounders with similar capabilities and orbits, so there is a great opportunity to compare their absolute calibration while they are both in orbit. This insures that long-term climate record can be created by concatenating the two instrument records. There are significant differences in instrument architecture which may lead to subtle differences and complicate any attempt to combine the records. We use Tropical Simultaneous Nadir Observations (TSNOs), cases where both instruments are looking nearly at the same place at the same time, to explore the differences. Differences are explored as a function of wavelength, day vs. night, land vs. ocean, and different levels of cloudiness. Differences unique to the design of each instrument are seen. With the currently available AIRS L1c and CrIS CCAST calibrated data radiometric differences as large a 0.3K are seen. These differences need to be corrected or at least flagged to prevent them from becoming artifacts in a long-term climate record.

  1. A New Radiometric Calibration Paradigm for the OMPS Nadir Total Column and Profile Instruments

    NASA Technical Reports Server (NTRS)

    Heath, Donald; Georgiew, Georgi

    2011-01-01

    A fused silica Mie Scattering Diffuser (MSD) has been developed at Ball Aerospace & Technology Corp. that has measured characteristics which could be used to increase the accuracy of the spectral albedo calibration of the Ozone Mapping and Profiler Suite (OMPS) Nadir ozone total column and profile instrument by almost an order of magnitude. Measurements have been made of the optical characteristics on both natural and synthetic forms of fused silica MSDs. Preliminary measurements suggest that MSDs are useable in the solar reflective wavelength region from 250 nm to 3.7 m. To date synthetic and natural MSDs have been irradiated for 60 hours of UV radiation from a solar simulator, and synthetic MSDs have been irradiated with increasing doses of Co-60 gamma rays at 30, 500 krads up to 1.5 Mrads, and 30 krads of 200 MeV protons. The principal effects have been small loses in transmittance at wavelengths < 350 nm. The high energy particle irradiation measurements were provided by Neal Nickles and Dean Spieth.

  2. Modelling Steep Surfaces by Various Configurations of Nadir and Oblique Photogrammetry

    NASA Astrophysics Data System (ADS)

    Casella, V.; Franzini, M.

    2016-06-01

    Among the parts of the territory requiring periodical and careful monitoring, many have steep surfaces: quarries, river basins, land-slides, dangerous mountainsides. Aerial photogrammetry based on lightweight unmanned aircraft systems (UAS) is rapidly becoming the tool of election to survey limited areas of land with a high level of detail. Aerial photogrammetry is traditionally based on vertical images and only recently the use of significantly inclined imagery has been considered. Oblique photogrammetry presents peculiar aspects and offers improved capabilities for steep surface reconstruction. Full comprehension of oblique photogrammetry still requires research efforts and the evaluation of diverse case studies. In the present paper, the focus is on the photogrammetric UAS-based survey of a part of a large sandpit. Various flight configurations are considered: ordinary linear strips, radial strips (as the scarp considered has a semi-circular shape) and curved ones; moreover, nadir looking and oblique image blocks were acquired. Around 300 control points were measured with a topographic total station. The various datasets considered are evaluated in terms of density of the extracted point cloud and in terms of the distance between the reconstructed surface and a number of check points.

  3. Second-Generation Multi-Angle Imaging Spectroradiometer

    NASA Technical Reports Server (NTRS)

    Macenka, Steven; Hovland, Larry; Preston, Daniel; Zellers, Brian; Downing, Kevin

    2004-01-01

    A report discusses an early phase in the development of the MISR-2 C, a second, improved version of the Multi-angle Imaging SpectroRadiometer (MISR), which has been in orbit around the Earth aboard NASA's Terra spacecraft since 1999. Like the MISR, the MISR-2 would contain a pushbroom array of nine charge-coupled- device (CCD) cameras one aimed at the nadir and the others aimed at different angles sideways from the nadir. The major improvements embodied in the MISR-2 would be the following: A new folded-reflective-optics design would render the MISR-2 only a third as massive as the MISR. Smaller filters and electronic circuits would enable a reduction in volume to a sixth of that of the MISR. The MISR-2 would generate images in two infrared spectral bands in addition to the blue, green, red, and near-infrared spectral bands of the MISR. Miniature polarization filters would be incorporated to add a polarization-sensing capability. Calibration would be performed nonintrusively by use of a gimbaled tenth camera. The main accomplishment thus far has been the construction of an extremely compact all-reflective-optics CCD camera to demonstrate feasibility.

  4. Evaluation of the Sensor Data Record from the Nadir Instruments of the Ozone Mapping Profiler Suite (OMPS)

    NASA Technical Reports Server (NTRS)

    Wu, Xiangqian; Liu, Quanhua; Zeng, Jian; Grotenhuis, Michael; Qian, Haifeng; Caponi, Maria; Flynn, Larry; Jaross, Glen; Sen, Bhaswar; Buss, Richard H., Jr.; Johnsen, William; Janz, Scott; Pan, Chunhui; Niu, Jianguo; Beck, Trevor; Beach, Eric; Yu, Wei; Raja, M. K. Rama Varma; Stuhmer, Derek; Cumpton, Daniel; Owen, Cristina; Li, Wen-Hao

    2014-01-01

    This paper evaluates the first 15 months of the Ozone Mapping and Profiler Suite (OMPS) Sensor Data Record (SDR) acquired by the nadir sensors and processed by the National Oceanic and Atmospheric Administration Interface Data Processing Segment. The evaluation consists of an inter-comparison with a similar satellite instrument, an analysis using a radiative transfer model, and an assessment of product stability. This is in addition to the evaluation of sensor calibration and the Environment Data Record product that are also reported in this Special Issue. All these are parts of synergetic effort to provide comprehensive assessment at every level of the products to ensure its quality. It is found that the OMPS nadir SDR quality is satisfactory for the current Provisional maturity. Methods used in the evaluation are being further refined, developed, and expanded, in collaboration with international community through the Global Space-based Inter-Calibration System, to support the upcoming long-term monitoring.

  5. Seismic Images of the Crust across D-E Seismic Profile (TS04-Tsujal Project): Results of Reflection and Wide-Angle Seismic Study

    NASA Astrophysics Data System (ADS)

    Nunez, D.; Lopez Ortiz, J. Y.; Bartolome, R.; Barba, D. C., Sr.; Nunez-Cornu, F. J.; Danobeitia, J.; Zamora-Camacho, A.; Escudero, C. R.

    2014-12-01

    As a part of TSUJAL Project (Crustal characterization of the Rivera Plate-Jalisco Block boundary and its implications for seismic and tsunami hazard assessment), a geophysical study has been carried out during February and March 2014 in western continental margin of Jalisco where seismic reflection, wide-angle seismic, bathymetry and potential fields (gravity and magnetism) data have been obtained. Eight land seismic stations vertical component and 4.5 Hz model TEXAN 125A (REFTEK), were deployed along an offshore-onshore seismic profile of 140 km length in SW-NE orientation. These stations registered, in continuous model, the airgun shots provided by RRS James Cook used for Multichannel Seismic Reflection data acquisition every 50 m of distance interval and total capacity of 5800 ci along seismic profile D-E (TS04). In the onshore region, these stations were deployed every 20 km from Pérula to Nacastillo (Jalisco, Mexico). The study region corresponds to onshore-offshore line limited by (18o 54'N, 105o 59'W) (19o 26'N, 105o7'W) coordinates. In this work, seismic images of the crust along a deep seismic profile of 140 km length are presented. These images provide new cortical information about the southern part of Rivera Plate, continental accretionary wedge and first kilometers of Jalisco Block continental zone.

  6. On Orbit Measurement of Response vs. Scan Angle for the Infrared Bands on TRMM/VIRS

    NASA Technical Reports Server (NTRS)

    Barnes, William L.; Lyu, Cheng-Hsuan; Barnes, Robert A.

    1999-01-01

    The Visible and Infrared Scanner on the Tropical Rainfall Measuring Mission (TRMM/VIRS) is a whiskbroom imaging radiometer with two reflected solar bands and three emissive infrared bands. All five detectors are on a single cooled focal plane. This configuration necessitated the use of a paddlewheel scan mirror to avoid the effects of focal plane rotation that arise when using a scan mirror that is inclined to its axis of rotation. System radiometric requirements led to the need for protected silver as the mirror surface. Unfortunately, the SiO(x) coatings currently used to protect silver from oxidation introduce a change in reflectance with angle of incidence (AOI). This AOI dependence results in a modulation of system level response with scan angle. Measurement of system response vs. scan angle (RVS) was not difficult for the VIRS reflected solar bands, but attaining the required accuracy for the IR bands in the laboratory was not possible without a large vacuum chamber and a considerable amount of custom designed testing apparatus. Therefore, the decision was made to conduct the measurement on-orbit. On three separate occasions, the TRMM spacecraft was rotated about its pitch axis and, after the nadir view passed over the Earth's limb, the VIRS performed several thousand scans while viewing deep space. The resulting data has been analyzed and the RVS curves generated for the three IR bands are being used in the VIRS radiometric calibration algorithm. This, to our knowledge, the first time this measurement has been made on-orbit. Similar measurements are planned for the EOS-AM and EOS-PM MODIS sensors and are being considered for several systems under development. The VIRS on-orbit results will be compared to VIRS and MODIS system level laboratory measurements, MODIS scan mirror witness sample measurements and modeled data.

  7. Low earth orbiting Nadir Etalon Sounding Spectrometer instrument concept for temperature, moisture and trace species, LeoNESS

    NASA Technical Reports Server (NTRS)

    Kumer, J. B.; Sterritt, L. W.; Roche, A. E.; Rosenberg, W. J.; Morrow, H. E.; Shenk, W. E.; Susskind, J.

    1992-01-01

    A concept for a low earth orbiting nadir etalon spectrometer sounder (LeoNESS) is described which can achieve retrieval of temperature, H2O, surface, boundary conditions, cloudiness, and trace species with an accuracy that meets or exceeds the AIRS specifications. Options employing 65-K and 30-K detectors are examined; the former may be implemented via passive radiative cooling. The concept, which is derived from the Cryogenic Limb Array Etalon Spectrometer, has the potential for improving the horizontal and vertical resolution.

  8. Atmospheric correction for ocean spectra retrievals from high-altitude multi-angle, multi-spectral photo-polarimetric remote sensing observations: Results for coastal ocean waters.

    NASA Astrophysics Data System (ADS)

    Chowdhary, J.; van Diedenhoven, B.; Knobelspiesse, K. D.; Cairns, B.; Wasilewski, A. P.; McCubbin, I.

    2015-12-01

    A major challenge for spaceborne observations of ocean color is to correct for atmospheric scattering, which typically contributes ≥85% to the top-of-atmosphere (TOA) radiance and varies substantially with aerosols. Ocean color missions traditionally analyze TOA radiance in the near-infrared (NIR), where the ocean is black, to constrain the TOA atmospheric scattering in the visible (VIS). However, this procedure is limited by insufficient sensitivity of NIR radiance to absorption and vertical distribution of aerosols, and by uncertainties in the extrapolation of aerosol properties from the NIR to the VIS.To improve atmospheric correction for ocean color observations, one needs to change the traditional procedure for this correction and/or increase the aerosol information. The instruments proposed to increase the aerosol information content for the Pre-Aerosol, Clouds, and ocean Ecosystem (PACE) mission include ultraviolet and Oxygen A-band observations, as well as multispectral and multiangle polarimetry. However few systematic studies have been performed to quantify the improvement such measurements bring to atmospheric correction. To study the polarimetric atmospheric correction capabilities of PACE-like instruments, we conducted field experiments off the Coast of California to obtain high-altitude (65,000 ft) and ship-based observations of water-leaving radiance. The airborne data sets consist of hyperspectral radiance between 380-2500 nm by the Airborne Visible/Infrared Imaging Spectrometer, and multi-spectral multi-angle polarimetric data between 410-2250 nm by the Research Scanning Polarimeter. We discuss examples of retrieved atmosphere and ocean state vectors, and of corresponding ocean color spectra obtained by subtracting the computed atmospheric scattering contribution from the high-altitude radiance measurements. The ocean color spectra thus obtained are compared with those measured from the ship.

  9. Daily Operational MODIS BRDF, Albedo and Nadir Reflectance Products (V006)

    NASA Astrophysics Data System (ADS)

    Schaaf, C.; Wang, Z.; Shuai, Y.; Strahler, A. H.

    2012-12-01

    The operational surface Bidirectional Reflectance Distribution Function (BRDF) and Albedo product (MCD43) has been produced for more than a decade from the MODerate resolution Imaging Spectroradiometer (MODIS) sensors aboard NASA's Terra and Aqua satellites. The Collection V005 operational product, reprocessed for the entire record, provides BRDF models, surface albedo quantities, and Nadir BRDF-Adjusted Reflectances (NBAR) globally on a 500m grid in a sinusoidal projection every 8 days (based on a 16 day window). As surface albedo is an essential climate variable (ECV), the accurate global estimations of terrestrial albedo provided by this product are used by numerous climate and biogeochemical modeling efforts. Of equal utility, the NBAR values are used as the primary inputs to the MODIS Land Cover product and (in the form of NBAR vegetation indices) are used for a variety of vegetation monitoring and phenological studies. Furthermore, the retrieved BRDF model parameters are increasingly being used to provide estimates of vegetation canopy variability and clumping. In the Collection V006 reprocessing effort, the standard global MODIS BRDF/Albedo product will finally be produced as a daily product (based on a 16 day moving window). The daily algorithm will rely on rolling multi-date directional surface reflectances to establish a general surface reflectance anisotropy model of the surface, while emphasizing the daily observation in an attempt to capture rapidly changing surface conditions. In order to improve retrievals over high latitudes and better capture snow covered and dormant vegetation conditions, more surface reflectances per day will be used in V006. Furthermore, the backup database (used to produce poorer quality magnitude inversions when high quality full retrievals are not possible) will now be continuously updated from the latest high quality full inversion for improved accuracy. The availability of daily V006 BRDF/albedo products will allow more

  10. The effect of data analysis techniques on the interpretation of wide-angle longwave radiation measurements

    NASA Technical Reports Server (NTRS)

    Green, R. N.

    1981-01-01

    Three different data analysis techniques - shape factor, parameter estimation, and deconvolution - have been applied to the same set of satellite radiation measurements to determine their effect on the estimated radiation field. The measurements are from a wide-angle, horizon-to-horizon, nadir-pointing sensor. The shape factor technique reduces each measurement to a radiant exitance at the top of the atmosphere by simple division by a constant. The parameter estimation technique processes all measurements together as a batch and defines the radiant exitance as a least-squares fit to the data. The deconvolution technique takes advantage of the fact that spherical harmonics are the eigenfunctions of the measurement operator. All three techniques are derived, and their assumptions, advantages and disadvantages are discussed. Their results are compared globally, zonally, regionally and on a spatial spectrum basis. All three techniques give comparable results for global parameters; however, results on a regional scale were quite different. The standard deviations of the regional differences in radiant exitance varied from 7.4 to 13.5 W/sq m. Of the three techniques, the parameter estimation technique produced the best regional results and is the choice of the author.

  11. Ozone assimilation in the UTLS: Value of limb-viewing sounders and resolution-dependent analysis of nadir data

    NASA Astrophysics Data System (ADS)

    Yudin, Valery; Pawson, Steven; Reinecker, Michele; Xu, Philippe; Sienkiewicz, Meta; Gille, John; Kinnison, Douglas; Livesey, Nathaniel

    2010-05-01

    The paper discusses aspects of the resolution-dependent analysis of ozone satellite data in the Upper Troposphere and Lower Stratosphere (UTLS) region. In this region the sharp positive and negative vertical ozone gradients are frequently observed by insitu measurements and simulated by chemistry-climate models, showing so-called ozone laminas. With sufficient vertical resolution of limb-viewing sensors, such as MLS and HIRDLS on Aura/NASA spacecraft, this information on ozone dynamics in thin vertical layers can be accepted by data assimilation systems constraining layered vertical ozone structures across the tropopause. For these scenes, the ozone-sensitive information from the nadir sensors (SBUV, GOME, TES, AIRS, OMI, IASI) characterized by restricted vertical resolution should be properly projected from the data space to the analysis grid preserving the non-observable (but forecasted) ozone vertical structures. Several illustrations for analysis of nadir-only ozone data (SBUV-2) that can "diffuse" ozone laminas in the extra-tropical UTLS are discussed. To overcome this negative impact of analysis of nadir data, the resolution-dependent analysis schemes (RDAS) of retrievals (characterized by kernels) or/and radiances are suggested. The vertical inverse mapping performed by RDAS ensures constraining only scales observable by data preserving the non-observable short-scale vertical structures of ozone. As illustrated by comparisons of MLS and HIRDLS data with analyzed ozone fields (GEOS-5 and ECMWF), the other geophysical scenes influenced by inadequate assimilation of nadir retrievals may include: a) the high-latitude ozone hole and mini-holes; b) seasonal and quasi-biennial ozone oscillations in the tropical stratosphere; c) movements of high and low ozone air masses across the transport barriers. These comparisons demonstrate the value of MLS and HIRDLS limb data in constraining of ozone for monitoring atmospheric composition and climate. The current plans for

  12. Small Angle Neutron Scattering

    SciTech Connect

    Urban, Volker S

    2012-01-01

    Small Angle Neutron Scattering (SANS) probes structural details at the nanometer scale in a non-destructive way. This article gives an introduction to scientists who have no prior small-angle scattering knowledge, but who seek a technique that allows elucidating structural information in challenging situations that thwart approaches by other methods. SANS is applicable to a wide variety of materials including metals and alloys, ceramics, concrete, glasses, polymers, composites and biological materials. Isotope and magnetic interactions provide unique methods for labeling and contrast variation to highlight specific structural features of interest. In situ studies of a material s responses to temperature, pressure, shear, magnetic and electric fields, etc., are feasible as a result of the high penetrating power of neutrons. SANS provides statistical information on significant structural features averaged over the probed sample volume, and one can use SANS to quantify with high precision the structural details that are observed, for example, in electron microscopy. Neutron scattering is non-destructive; there is no need to cut specimens into thin sections, and neutrons penetrate deeply, providing information on the bulk material, free from surface effects. The basic principles of a SANS experiment are fairly simple, but the measurement, analysis and interpretation of small angle scattering data involves theoretical concepts that are unique to the technique and that are not widely known. This article includes a concise description of the basics, as well as practical know-how that is essential for a successful SANS experiment.

  13. VHF Radar Measurements of Tropical Forests in Panama: Results from the BioSAR Deployment in Central America

    NASA Technical Reports Server (NTRS)

    Imhoff, Marc; Lawrence, William; Condit, Richard; Wright, Joseph; Johnson, Patrick; Holford, Warren; Hyer, Joseph; May, Lisa; Carson, Steven

    2000-01-01

    A synthetic aperture radar sensor operating in 5 bands between 80 and 120 MHz was flown over forested areas in the canal zone of the Republic of Panama in an experiment to measure biomass in heavy tropical forests. The sensor is a pulse coherent SAR flown on a small aircraft and oriented straight down. The doppler history is processed to collect data on the ground in rectangular cells of varying size over a range of incidence angles fore and aft of nadir (+45 to - 45 degrees). Sensor data consists of 5 frequency bands with 20 incidence angles per band. Sensor data for over 12+ sites were collected with forest stands having biomass densities ranging from 50 to 300 tons/ha dry above ground biomass. Results are shown exploring the biomass saturation thresholds using these frequencies, the system design is explained, and preliminary attempts at data visualization using this unique sensor design are described.

  14. Long-term nadir observations of the O2 dayglow by SPICAM IR

    NASA Astrophysics Data System (ADS)

    Guslyakova, S.; Fedorova, A.; Lefèvre, F.; Korablev, O.; Montmessin, F.; Trokhimovskiy, A.; Bertaux, J. L.

    2016-03-01

    The O2(a1Δg) dayglow at the 1.27 μm band on Mars is produced by the solar UV photolysis of ozone and quenched in collisions with CO2. The SPICAM IR instrument onboard the Mars Express orbiter observes the O2(a1Δg) emission in the Martian atmosphere starting from 2004. We present a continuous set of O2(a1Δg) dayglow intensities from nadir measurements for six Martian years from the end of MY26 to MY32. Maximum values of the O2(a1Δg) dayglow reaching 31 MR were observed in early northern and southern springs in both hemispheres. Near the equator a spring maximum of 5-8 MR was observed for all years. The emission intensity is minimum in the Southern hemisphere in summer with values of 1-2 MR. Comparison of the data with GCM simulations and simultaneous ozone measurements by SPICAM UV allows to derive the quenching rate (k) of the excited O2 molecules by CO2, k=0.73×10-20 cm3 molecules-1 s-1. The interannual variation of the O2 emission has been studied after applying correction for the local time. The O2(a1Δg) seasonal pattern is rather stable with average year-to-year relative variation of about 21%, in accord with interannual variations detected from the ground (Krasnopolsky, 2013). The most variable region corresponds to northern and southern spring at middle latitudes, coinciding with sublimation of the polar caps in both hemispheres. Southern latitudes also show a high year-to-year variability in summer (Ls=270-330°) relating to the dust activity in this region. A comparison with simultaneous SPICAM water vapor observations shows that the O2(a1Δg) dayglow depends on the water vapor variations, and clearly confirms their anti-correlation, excepting the case of low and middle latitudes in the aphelion period.

  15. Laser angle measurement system

    NASA Technical Reports Server (NTRS)

    Pond, C. R.; Texeira, P. D.; Wilbert, R. E.

    1980-01-01

    The design and fabrication of a laser angle measurement system is described. The instrument is a fringe counting interferometer that monitors the pitch attitude of a model in a wind tunnel. A laser source and detector are mounted above the mode. Interference fringes are generated by a small passive element on the model. The fringe count is accumulated and displayed by a processor in the wind tunnel control room. Optical and electrical schematics, system maintenance and operation procedures are included, and the results of a demonstration test are given.

  16. Hysteresis during contact angles measurement.

    PubMed

    Diaz, M Elena; Fuentes, Javier; Cerro, Ramon L; Savage, Michael D

    2010-03-15

    A theory, based on the presence of an adsorbed film in the vicinity of the triple contact line, provides a molecular interpretation of intrinsic hysteresis during the measurement of static contact angles. Static contact angles are measured by placing a sessile drop on top of a flat solid surface. If the solid surface has not been previously in contact with a vapor phase saturated with the molecules of the liquid phase, the solid surface is free of adsorbed liquid molecules. In the absence of an adsorbed film, molecular forces configure an advancing contact angle larger than the static contact angle. After some time, due to an evaporation/adsorption process, the interface of the drop coexists with an adsorbed film of liquid molecules as part of the equilibrium configuration, denoted as the static contact angle. This equilibrium configuration is metastable because the droplet has a larger vapor pressure than the surrounding flat film. As the drop evaporates, the vapor/liquid interface contracts and the apparent contact line moves towards the center of the drop. During this process, the film left behind is thicker than the adsorbed film and molecular attraction results in a receding contact angle, smaller than the equilibrium contact angle. PMID:20060981

  17. NOMAD, a spectrometer suite for Nadir and Solar Occultation observations on the ExoMars Trace Gas Orbiter

    NASA Astrophysics Data System (ADS)

    Drummond, Rachel; Robert, Severine; Vandaele, Ann-Carine; Willame, Yannick; Lopez-Moreno, Jose Juan; Patel, Manish; Belluci, Giancarlo; Daerden, Frank; Neefs, Eddy; Rodriguez-Gomez, Julio

    2013-04-01

    NOMAD, the "Nadir and Occultation for MArs Discovery" spectrometer suite was selected as part of the payload of the ExoMars Trace Gas Orbiter mission 2016. This instrument suite will conduct a spectroscopic survey of Mars' atmosphere in the UV, visible and IR regions covering the 0.2-0.65 and 2.2-4.3 µm spectral ranges. NOMAD's observation modes include solar occultation, nadir and limb observations. The NOMAD instrument is composed of 3 channels: a solar occultation only channel (SO) operating in the infrared wavelength domain, a second infrared channel capable of doing nadir, but also solar occultation and limb observations (LNO), and an ultraviolet/visible channel (UVIS) that can work in all observation modes. The spectral resolution of SO and LNO surpasses previous surveys in the infrared by more than one order of magnitude. NOMAD offers an integrated instrument combination of a flight-proven concept (SO is a copy of SOIR on Venus Express), and innovations based on existing and proven instrumentation (LNO is based on SOIR/VEX and UVIS has heritage from the ExoMars lander), that will provide mapping and vertical profile information at high spatio-temporal resolution. The three channels have each their own ILS and optical bench, but share the same single interface to the S/C. We will present the instrument and its capabilities in term of detection of a broad suite of species, its possibilities to improve our knowledge on vertical structure of the atmosphere as well as its mapping possibilities. Since last year's abstract, much progress has been made on the instrument design and prototypes have been tested, especially concerning the very challenging thermal needs of the instrument. This paper will concentrate on the developments in the last year that prove NOMAD will be a very powerful, sensitive instrument.

  18. NOMAD, a spectrometer suite for Nadir and Solar Occultation observations on the ExoMars Trace Gas Orbiter

    NASA Astrophysics Data System (ADS)

    Vandaele, A. C.; López-Moreno, J.-J.; Patel, M. R.; Bellucci, G.; Daerden, F.; Drummond, R.; Neefs, E.; Robert, S.; Rodriguez Gomez, J.

    2012-04-01

    NOMAD, the "Nadir and Occultation for MArs Discovery" spectrometer suite has been selected by ESA and NASA to be part of the payload of the ExoMars Trace Gas Orbiter mission 2016. This instrument suite will conduct a spectroscopic survey of Mars' atmosphere in the UV, visible and IR regions covering the 0.2-0.65 and 2.2-4.3 μm spectral ranges. NOMAD's observation modes include solar occultation, nadir and limb observations. The NOMAD instrument is composed of 3 channels: a solar occultation only channel (SO) operating in the infrared wavelength domain, a second infrared channel capable of doing nadir, but also solar occultation and limb observations (LNO), and an ultraviolet/visible channel (UVIS) that can work in all observation modes. The spectral resolution of SO and LNO surpasses previous surveys in the infrared by more than one order of magnitude. NOMAD offers an integrated instrument combination of a flight-proven concept (SO is a copy of SOIR on Venus Express), and innovations based on existing and proven instrumentation (LNO is based on SOIR/VEX and UVIS has heritage from the ExoMars lander), that will provide mapping and vertical profile information at high spatio-temporal resolution. The three channels have each their own ILS and optical bench, but share the same single interface to the S/C. We will present the instrument and its capabilities in term of detection of a broad suite of species, its possibilities to improve our knowledge on vertical structure of the atmosphere as well as its mapping possibilities.

  19. MISR Multi-angle Views of Sunday Morning Fires

    NASA Technical Reports Server (NTRS)

    2007-01-01

    Hot, dry Santa Ana winds began blowing through the Los Angeles and San Diego areas on Sunday October 21, 2007. Wind speeds ranging from 30 to 50 mph were measured in the area, with extremely low relative humidities. These winds, coupled with exceptionally dry conditions due to lack of rainfall resulted in a number of fires in the Los Angeles and San Diego areas, causing the evacuation of more than 250,000 people.

    These two images show the Southern California coast from Los Angeles to San Diego from two of the nine cameras on the Multi-angle Imaging SpectroRadiometer (MISR) instrument on the NASA EOS Terra satellite. These images were obtained around 11:35 a.m. PDT on Sunday morning, October 21, 2007 and show a number of plumes extending out over the Pacific ocean. In addition, locations identified as potential hot spots from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on the same satellite are outlined in red.

    The left image is from MISR's nadir looking camera and the plumes appear very faint. The image on the right is from MISR's 60o forward looking camera, which accentuates the amount of light scattered by aerosols in the atmosphere, including smoke and dust. Both these images are false color and contain information from MISR's red, green, blue and near-infrared wavelengths, which makes vegetated land appear greener than it would naturally. Notice in the right hand image that the color of the plumes associated with the MODIS hot spots is bluish, while plumes not associated with hot spots appear more yellow. This is because the latter plumes are composed of dust kicked up by the strong Santa Ana winds. In some locations along Interstate 5 on this date, visibility was severely reduced due to blowing dust. MISR's multiangle and multispectral capability give it the ability to distinguish smoke from dust in this situation.

    The Multi-angle Imaging SpectroRadiometer observes the daylit Earth continuously and every 9 days

  20. Circuitry for Angle Measurements

    NASA Technical Reports Server (NTRS)

    Currie, J. R.; Kissel, R. R.

    1983-01-01

    Angle resolver pulsed and read under microprocessor control. Pulse generator excites resolver windings with dual slope pulse. System sequentially reads sine and cosine windings. Microprocessor determines angle through which resolver shaft turned from reference angle. Suitable applications include rate tables, antenna direction controllers, and machine tools.

  1. Data Plots of Run I - III Results from SLAC E-158: A precision Measurement of the Weak Mixing Angle in Moller Scattering

    DOE Data Explorer

    Three physics runs were made in 2002 and 2003 by E-158. As a result, the E-158 Collaboration announced that it had made "the first observation of Parity Violation in electron-electron (Moller) scattering). This precise Parity Violation measurement gives the best determination of the electron's weak charge at low energy (low momentum transfer between interacting particles). E158's measurement tests the predicted running (or evolution) of this weak charge with energy, and searches for new phenomena at TeV energy scales (one thousand times the proton-mass energy scale).[Copied from the experiment's public home page at http://www-project slac.stanford.edu/3158/Default.htm] See also the E158 page for collaborators at http://www.slac.stanford.edu/exp/e158/. Both websites provide data and detailed information.

  2. The measurement of boundary layers on a compressor blade in cascade at high positive incidence angle. 1: Experimental techniques and results

    NASA Technical Reports Server (NTRS)

    Deutsch, S.; Zierke, W. C.

    1986-01-01

    Measurements of the mean velocity and turbulence intensity were made using a one-component laser Doppler velocimeter in the boundary layer and near wake about a double circular arc, compressor blade in cascade. The measurements were made at a chord Reynolds number of 500,000. Boundary layer measurements on the pressure surface indicate a transition region over the last 40% of the chord. A small separation bubble near the leading edge of the suction surface results in an immediate transition from laminar to turbulent flow. The non-equilibrium turbulent boundary layer separates near the trailing edge of the suction surface. Similarity of the outer region of the turbulent boundary layer ceases to exist in the separated region. Also, similarity does not hold in the near-wake region, a region which includes negative mean velocities because of the separation near the trailing edge on the suction surface.

  3. Effects of skylight polarization, cloudiness, and view angle on the detection of oil on water.

    NASA Technical Reports Server (NTRS)

    Millard, J. P.; Arvesen, J. C.

    1971-01-01

    Three passive radiometric techniques, which use the contrast of sunlight reflected and backscattered from oil and water in specific wavelength regions, have potential application for remote sensing of oil spills. These techniques consist of measuring (1) total radiance, (2) the polarization components (normal and parallel) of radiance, and (3) the difference between the normal and parallel components. In this paper, the best view directions for these techniques are evaluated, conclusions are drawn as to the most promising technique, and explanations are developed to describe why previous total-radiance measurements yielded highest contrast between oil and water under overcast skies. The technique based on measurement of only the normal polorization component appears to be the most promising. The differential technique should be further investigated because of its potential to reduce the component of backscattered light from below the surface of the water. Measurements should be made about 45 deg nadir view angle in the direction opposite the sun. Overcast sky conditions provide a higher intensity of skylight relative to clear sky conditions and a lower intensity of backscatter within the water relative to surface reflectance. These factors result in higher contrast between oil and water under overcast skies.

  4. Wide Angle Imaging Lidar (WAIL): Theory of Operation and Results from Cross-Platform Validation at the ARM Southern Great Plains Site

    NASA Astrophysics Data System (ADS)

    Polonsky, I. N.; Davis, A. B.; Love, S. P.

    2004-05-01

    WAIL was designed to determine physical and geometrical characteristics of optically thick clouds using the off-beam component of the lidar return that can be accurately modeled within the 3D photon diffusion approximation. The theory shows that the WAIL signal depends not only on the cloud optical characteristics (phase function, extinction and scattering coefficients) but also on the outer thickness of the cloud layer. This makes it possible to estimate the mean optical and geometrical thicknesses of the cloud. The comparison with Monte Carlo simulation demonstrates the high accuracy of the diffusion approximation for moderately to very dense clouds. During operation WAIL is able to collect a complete data set from a cloud every few minutes, with averaging over horizontal scale of a kilometer or so. In order to validate WAIL's ability to deliver cloud properties, the LANL instrument was deployed as a part of the THickness from Off-beam Returns (THOR) validation IOP. The goal was to probe clouds above the SGP CART site at night in March 2002 from below (WAIL and ARM instruments) and from NASA's P3 aircraft (carrying THOR, the GSFC counterpart of WAIL) flying above the clouds. The permanent cloud instruments we used to compare with the results obtained from WAIL were ARM's laser ceilometer, micro-pulse lidar (MPL), millimeter-wavelength cloud radar (MMCR), and micro-wave radiometer (MWR). The comparison shows that, in spite of an unusually low cloud ceiling, an unfavorable observation condition for WAIL's present configuration, cloud properties obtained from the new instrument are in good agreement with their counterparts obtained by other instruments. So WAIL can duplicate, at least for single-layer clouds, the cloud products of the MWR and MMCR together. But WAIL does this with green laser light, which is far more representative than microwaves of photon transport processes at work in the climate system.

  5. Off-nadir antenna bias correction using Amazon rain forest sigma deg data. [Brazil

    NASA Technical Reports Server (NTRS)

    Birrer, I. J.; Bracalente, E. M.; Dome, G. J.; Sweet, J.; Berthold, G.; Moore, R. K. (Principal Investigator)

    1981-01-01

    The radar response from the Amazon rain forest was studied to determine the suitability of this region for use as a standard target to calibrate a scatterometer like that proposed for the National Ocean Satellite System (NOSS). Backscattering observations made by the SEASAT-1 scatterometer system show the Amazon rain forest to be a homogeneous, azimuthally-isotropic, radar target which is insensitive to polarization. The variation with angle of incidence may be adequately modeled as sigma deg (dB) = alpha theta + beta with typical values for the incidence-angle coefficient from 0.07 dB deg to 0.15 dB/deg. A small diurnal effect occurs, with measurements at sunrise being 0.5 dB to 1 dB higher than the rest of the day. Maximum likelihood estimation algorithms are presented which permit determination of relative bias and true pointing angle for each beam. Specific implementation of these algorithms for the proposed NOSS scatterometer system is also discussed.

  6. Off-nadir antenna bias correction using Amazon rain sigma(0) data

    NASA Technical Reports Server (NTRS)

    Birrer, I. J.; Dome, G. J.; Sweet, J.; Berthold, G.; Moore, R. K.

    1982-01-01

    The radar response from the Amazon rain forest was studied to determine the suitability of this region for use as a standard target to calibrate a scatterometer like that proposed for the National Oceanic Satellite System (NOSS). Backscattering observations made by the SEASAT Scatterometer System (SASS) showed the Amazon rain forest to be a homogeneous, azimuthally-isotropic, radar target which was insensitive to polarization. The variation with angle of incidence was adequately modeled as scattering coefficient (dB) = a theta b with typical values for the incidence-angle coefficient from 0.07 to 0.15 dB/deg. A small diurnal effect occurs, with measurements at sunrise being 0.5 dB to 1 dB higher than the rest of the day. Maximum-likelihood estimation algorithms presented here permit determination of relative bias and true pointing angle for each beam. Specific implementation of these algorithms for the proposed NOSS scatterometer system is also discussed.

  7. The topographic effect on spectral response from nadir-pointing sensors

    NASA Technical Reports Server (NTRS)

    Holben, B. N.; Justice, C. O.

    1980-01-01

    It is difficult to interpret multispectral Landsat earth resources data in areas of rugged and mountainous terrain because of the topographic effect on the sensor response. The objectives of this study were to examine and quantify the topographic effect on the sensor response from a uniform sand surface, to assess a simple theoretical incidence model for modeling the radiance from the surface, and to simulate Landsat sensor response due to the topographic effect. A field experiment was designed to collect data from a large range of slope angles and aspects at a range of solar elevations, using a hand-held radiometer. Analysis of these data showed that the magnitude of the topographic effect varied as a function of the solar elevation, the azimuthal orientation of the slope, and the slope inclination. The field measured variations in spectral response were found to have generally strong correlations with the theoretical model, and it was shown that the applicability of the Lambertian assumption varied within and between data sets. It is concluded that if slope angle, aspect, and solar zenith angle and azimuth are known, a technique incorporating a model to reduce the topographic effect prior to multispectral classification may be developed.

  8. From plane to spatial angles: PTB's spatial angle autocollimator calibrator

    NASA Astrophysics Data System (ADS)

    Kranz, Oliver; Geckeler, Ralf D.; Just, Andreas; Krause, Michael; Osten, Wolfgang

    2015-10-01

    Electronic autocollimators are utilised versatilely for non-contact angle measurements in applications like straightness measurements and profilometry. Yet, no calibration of the angle measurement of an autocollimator has been available when both its measurement axes are engaged. Additionally, autocollimators have been calibrated at fixed distances to the reflector, although its distance may vary during the use of an autocollimator. To extend the calibration capabilities of the Physikalisch-Technische Bundesanstalt (PTB) regarding spatial angles and variable distances, a novel calibration device has been set up: the spatial angle autocollimator calibrator (SAAC). In this paper, its concept and its mechanical realisation will be presented. The focus will be on the system's mathematical modelling and its application in spatial angle calibrations. The model considers the misalignments of the SAAC's components, including the non-orthogonalities of the measurement axes of the autocollimators and of the rotational axes of the tilting unit. It allows us to derive specific measurement procedures to determine the misalignments in situ and, in turn, to correct the measurements of the autocollimators. Finally, the realisation and the results of a traceable spatial angle calibration of an autocollimator will be presented. This is the first calibration of this type worldwide.

  9. Measures on mixing angles

    SciTech Connect

    Gibbons, Gary W.; Gielen, Steffen; Pope, C. N.; Turok, Neil

    2009-01-01

    We address the problem of the apparently very small magnitude of CP violation in the standard model, measured by the Jarlskog invariant J. In order to make statements about probabilities for certain values of J, we seek to find a natural measure on the space of Kobayashi-Maskawa matrices, the double quotient U(1){sup 2}/SU(3)/U(1){sup 2}. We review several possible, geometrically motivated choices of the measure, and compute expectation values for powers of J for these measures. We find that different choices of the measure generically make the observed magnitude of CP violation appear finely tuned. Since the quark masses and the mixing angles are determined by the same set of Yukawa couplings, we then do a second calculation in which we take the known quark mass hierarchy into account. We construct the simplest measure on the space of 3x3 Hermitian matrices which reproduces this known hierarchy. Calculating expectation values for powers of J in this second approach, we find that values of J close to the observed value are now rather likely, and there does not seem to be any fine-tuning. Our results suggest that the choice of Kobayashi-Maskawa angles is closely linked to the observed mass hierarchy. We close by discussing the corresponding case of neutrinos.

  10. Round-robin evaluation of nadir ozone profile retrievals: methodology and application to MetOp-A GOME-2

    NASA Astrophysics Data System (ADS)

    Keppens, A.; Lambert, J.-C.; Granville, J.; Miles, G.; Siddans, R.; van Peet, J. C. A.; van der A, R. J.; Hubert, D.; Verhoelst, T.; Delcloo, A.; Godin-Beekmann, S.; Kivi, R.; Stubi, R.; Zehner, C.

    2015-05-01

    A methodology for the round-robin evaluation and the geophysical validation of ozone profile data retrieved from nadir UV backscatter satellite measurements is detailed and discussed, consisting of data set content studies, information content studies, co-location studies, and comparisons with reference measurements. Within the European Space Agency's Climate Change Initiative on ozone (Ozone_cci project), the proposed round-robin procedure is applied to two nadir ozone profile data sets retrieved at the Royal Netherlands Meteorological Institute (KNMI) and the Rutherford Appleton Laboratory (RAL, United Kingdom), using their respective OPERA v1.26 and RAL v2.1 optimal estimation algorithms, from MetOp-A GOME-2 (i.e. the second generation Global Ozone Monitoring Experiment on the first Meteorological Operational Satellite) measurements taken in 2008. The ground-based comparisons use ozonesonde and lidar profiles as reference data, acquired by the Network for the Detection of Atmospheric Composition Change (NDACC), Southern Hemisphere Additional Ozonesonde programme (SHADOZ), and other stations of the World Meteorological Organisation's Global Atmosphere Watch (WMO GAW). This direct illustration highlights practical issues that inevitably emerge from discrepancies in e.g. profile representation and vertical smoothing, for which different recipes are investigated and discussed. Several approaches for information content quantification, vertical resolution estimation, and reference profile resampling are compared and applied as well. The paper concludes with compliance estimates of the two GOME-2 ozone profile data sets with user requirements from the Global Climate Observing System (GCOS) and from climate modellers.

  11. Multi-Angle View of the Canary Islands

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A multi-angle view of the Canary Islands in a dust storm, 29 February 2000. At left is a true-color image taken by the Multi-angle Imaging SpectroRadiometer (MISR) instrument on NASA's Terra satellite. This image was captured by the MISR camera looking at a 70.5-degree angle to the surface, ahead of the spacecraft. The middle image was taken by the MISR downward-looking (nadir) camera, and the right image is from the aftward 70.5-degree camera. The images are reproduced using the same radiometric scale, so variations in brightness, color, and contrast represent true variations in surface and atmospheric reflectance with angle. Windblown dust from the Sahara Desert is apparent in all three images, and is much brighter in the oblique views. This illustrates how MISR's oblique imaging capability makes the instrument a sensitive detector of dust and other particles in the atmosphere. Data for all channels are presented in a Space Oblique Mercator map projection to facilitate their co-registration. The images are about 400 km (250 miles)wide, with a spatial resolution of about 1.1 kilometers (1,200 yards). North is toward the top. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

  12. PSA Nadir of <0.5 ng/mL Following Brachytherapy for Early-Stage Prostate Adenocarcinoma is Associated With Freedom From Prostate-Specific Antigen Failure

    SciTech Connect

    Ko, Eric C.; Stone, Nelson N.; Stock, Richard G.

    2012-06-01

    Purpose: Because limited information exists regarding whether the rate or magnitude of PSA decline following brachytherapy predicts long-term clinical outcomes, we evaluated whether achieving a prostate-specific antigen (PSA) nadir (nPSA) <0.5 ng/mL following brachytherapy is associated with decreased PSA failure and/or distant metastasis. Methods and Materials: We retrospectively analyzed our database of early-stage prostate adenocarcinoma patients who underwent brachytherapy, excluding those receiving androgen-deprivation therapy and those with <2 years follow-up. Median and mean pretreatment PSA were 6 ng/mL and 7.16 ng/mL, respectively. By clinical stage, 775 were low risk ({<=}T2a), 126 were intermediate risk (T2b), and 20 were high risk (>T2b). By Gleason score, 840 were low risk ({<=}6), 71 were intermediate risk (7), and 10 were high risk (>7). Patients were treated with brachytherapy only (I-125, n = 779, or Pd-103, n = 47), or brachytherapy + external-beam radiation therapy (n = 95). Median follow-up was 6.3 years. We noted whether nPSA <0.5 ng/mL was achieved and the time to achieve this nadir and tested for associations with pretreatment risk factors. We also determined whether this PSA endpoint was associated with decreased PSA failure or distant metastasis. Results: Absence of high-risk factors in clinical stage ({<=}T2b), Gleason score ({<=}7), and pretreatment PSA ({<=}20 ng/mL) was significantly associated with achieving nPSA <0.5 ng/mL. By Kaplan-Meier analysis, patients achieving nPSA <0.5 ng/mL had significantly higher long-term freedom from biochemical failure (FFBF) than nonresponders (5-year FFBF: 95.2 {+-} 0.8% vs. 71.5 {+-} 6.7%; p < 0.0005). Among responders, those who achieved nPSA <0.5 ng/mL in {<=}5 years had higher FFBF than those requiring >5 years (5-year FFBF: 96.7 {+-} 0.7% vs. 80.8 {+-} 4.6%; p < 0.0005). On multivariate analysis, patients who achieved nPSA <0.5 ng/mL in {<=}5 years had significantly higher FFBF than other

  13. The Feasibility of Tropospheric and Total Ozone Determination Using a Fabry-perot Interferometer as a Satellite-based Nadir-viewing Atmospheric Sensor. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Larar, Allen Maurice

    1993-01-01

    Monitoring of the global distribution of tropospheric ozone (O3) is desirable for enhanced scientific understanding as well as to potentially lessen the ill-health impacts associated with exposure to elevated concentrations in the lower atmosphere. Such a capability can be achieved using a satellite-based device making high spectral resolution measurements with high signal-to-noise ratios; this would enable observation in the pressure-broadened wings of strong O3 lines while minimizing the impact of undesirable signal contributions associated with, for example, the terrestrial surface, interfering species, and clouds. The Fabry-Perot Interferometer (FPI) provides high spectral resolution and high throughput capabilities that are essential for this measurement task. Through proper selection of channel spectral regions, the FPI optimized for tropospheric O3 measurements can simultaneously observe a stratospheric component and thus the total O3 column abundance. Decreasing stratospheric O3 concentrations may lead to an increase in biologically harmful solar ultraviolet radiation reaching the earth's surface, which is detrimental to health. In this research, a conceptual instrument design to achieve the desired measurement has been formulated. This involves a double-etalon fixed-gap series configuration FPI along with an ultra-narrow bandpass filter to achieve single-order operation with an overall spectral resolution of approximately .068 cm(exp -1). A spectral region of about 1 cm(exp -1) wide centered at 1054.73 cm(exp -1) within the strong 9.6 micron ozone infrared band is sampled with 24 spectral channels. Other design characteristics include operation from a nadir-viewing satellite configuration utilizing a 9 inch (diameter) telescope and achieving horizontal spatial resolution with a 50 km nadir footprint. A retrieval technique has been implemented and is demonstrated for a tropical atmosphere possessing enhanced tropospheric ozone amounts. An error analysis

  14. Results.

    ERIC Educational Resources Information Center

    Zemsky, Robert; Shaman, Susan; Shapiro, Daniel B.

    2001-01-01

    Describes the Collegiate Results Instrument (CRI), which measures a range of collegiate outcomes for alumni 6 years after graduation. The CRI was designed to target alumni from institutions across market segments and assess their values, abilities, work skills, occupations, and pursuit of lifelong learning. (EV)

  15. The First Eighteen Months of NASA's Orbiting Carbon Observatory-2 (OCO-2): Mission Status, Error Characterization, and Preliminary Results

    NASA Astrophysics Data System (ADS)

    O'Dell, Christopher

    2016-04-01

    OCO-2 began taking science data in September 2014 and continues to operate well, returning nearly 1 million observations per day. Approximately 10% of these are sufficiently free of cloud and aerosol contamination to allow for an accurate determination of the column mean carbon dioxide dry air mole fraction, XCO2. The measurements have relatively low noise, of order 0.5-1.0 ppm for most nadir soundings over land and sun-glint geometry soundings over water surfaces. A number of changes have been made to the observing strategy to maintain performance and enhance the science quality of the data: change in glint yaw angle in October 2014, change in nadir glint cycling in July 2015, change to nadir yaw and glint orbit optimization in late 2015, in addition to periodic instrument cyclings. In this presentation, we will summarize the data quality enabled via comparison to a number of validation metrics, discuss the current health and long-term prospects for the instrument, and give an overview of some early science results from the first 18 months of observations. While XCO2 and other products are still being validated to identify and correct biases, OCO-2's XCO2 observations are starting to reveal the most robust features of the atmospheric carbon cycle. At regional scales, fluxes from the eastern U.S. and China are most clear in the fall, when the north-south XCO2 gradient is small. Enhanced XCO2 coincident with biomass burning in the some parts of the tropics, in particular central Africa, is also obvious in the fall. The annual growth rate of CO2 was anomalously high in 2015 according to OCO-2, consistent with NOAA surface measurements and in accord with the warmer annual average surface temperature that year. This was also apparent in the decreased northern hemisphere summer uptake, likely due to anomalously warm boreal temperatures in the northern hemisphere summer of 2015.

  16. Reading Angles in Maps

    ERIC Educational Resources Information Center

    Izard, Véronique; O'Donnell, Evan; Spelke, Elizabeth S.

    2014-01-01

    Preschool children can navigate by simple geometric maps of the environment, but the nature of the geometric relations they use in map reading remains unclear. Here, children were tested specifically on their sensitivity to angle. Forty-eight children (age 47:15-53:30 months) were presented with fragments of geometric maps, in which angle sections…

  17. Solar angle reference manual

    SciTech Connect

    Sibson, R.

    1983-01-01

    The introduction is the only text in the volume; the rest of the book contains easy-to-use graphical methods for building design and construction using solar energy. Isogonic charts and solar angle diagrams are included. Isogonic charts. Solar angle diagrams.

  18. Multi-Angle Views of the Appalachian Mountains, 6 March 2000

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The true-color image at left is a downward-looking (nadir) view of the eastern United States, stretching from Lake Ontario to northern Georgia, and spanning the Appalachian Mountains. The three images to the right are also in true-color, taken by the forward 45.6-degree, 60.0-degree, and 70.5-degree cameras, respectively, of the Multi-angle Imaging SpectroRadiometer (MISR) instrument on NASA's Terra satellite. As the slant angle increases, the line-of-sight through the atmosphere grows longer, and a pall of haze over the Appalachians becomes progressively more apparent. You can see a similar effect by scanning from near-nadir to the horizon when standing on a mountain top or looking out an airplane window. MISR uses this multi-angle technique to monitor particulate pollution and to distinguish different types of haze. These observations reveal how airborne particles are interacting with sunlight, a measure of their impact on Earth's climate system. The images are about 400 km (250 miles) wide, and the spatial resolution is 1.1 kilometers (1,200 yards). North is toward the top. MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

  19. Metrology of angles in astronomy

    NASA Astrophysics Data System (ADS)

    Kovalevsky, Jean

    2004-10-01

    In astronomy, measurements of angles play a major role. After defining the units in use in astronomy, three methods of measuring angles are presented, with an application to the transit instrument. The interferometric techniques for measuring large angles are described in optical and radio wavelengths. Due to the atmospheric and mechanical limitation on ground, space astrometry has multiple advantages. The satellite Hipparcos is described and the data reduction procedures and results obtained are sketched. In the future, two new astrometric space missions are approved: GAIA, based on Hipparcos principles and SIM, a space interferometer. They are described and the expected accuracies are presented. To cite this article: J. Kovalevsky, C. R. Physique 5 (2004).

  20. Photoelectric angle converter

    NASA Astrophysics Data System (ADS)

    Podzharenko, Volodymyr A.; Kulakov, Pavlo I.

    2001-06-01

    The photo-electric angle transmitter of rotation is offered, at which the output voltage is linear function of entering magnitude. In a transmitter the linear phototransducer is used on the basis of pair photo diode -- operating amplifier, which output voltage is linear function of the area of an illuminated photosensitive stratum, and modulator of a light stream of the special shape, which ensures a linear dependence of this area from an angle of rotation. The transmitter has good frequent properties and can be used for dynamic measurements of an angular velocity and angle of rotation, in systems of exact drives and systems of autocontrol.

  1. Reading Angles in Maps

    PubMed Central

    Izard, Véronique; O'Donnell, Evan; Spelke, Elizabeth S.

    2013-01-01

    Preschool children can navigate by simple geometric maps of the environment, but the nature of the geometric relations they use in map reading remains unclear. Here, children were tested specifically on their sensitivity to angle. Forty-eight children (age 47:15–53:30 months) were presented with fragments of geometric maps, in which angle sections appeared without any relevant length or distance information. Children were able to read these map fragments and compare 2D to 3D angles. However, this ability appeared both variable and fragile among the youngest children of the sample. These findings suggest that 4-year-old children begin to form an abstract concept of angle that applies both to 2D and 3D displays and that serves to interpret novel spatial symbols. PMID:23647223

  2. Angles, Time, and Proportion

    ERIC Educational Resources Information Center

    Pagni, David L.

    2005-01-01

    This article describes an investigation making connections between the time on an analog clock and the angle between the minute hand and the hour hand. It was posed by a middle school mathematics teacher. (Contains 8 tables and 6 figures.)

  3. Reading angles in maps.

    PubMed

    Izard, Véronique; O'Donnell, Evan; Spelke, Elizabeth S

    2014-01-01

    Preschool children can navigate by simple geometric maps of the environment, but the nature of the geometric relations they use in map reading remains unclear. Here, children were tested specifically on their sensitivity to angle. Forty-eight children (age 47:15-53:30 months) were presented with fragments of geometric maps, in which angle sections appeared without any relevant length or distance information. Children were able to read these map fragments and compare two-dimensional to three-dimensional angles. However, this ability appeared both variable and fragile among the youngest children of the sample. These findings suggest that 4-year-old children begin to form an abstract concept of angle that applies both to two-dimensional and three-dimensional displays and that serves to interpret novel spatial symbols. PMID:23647223

  4. Estimation of Sea Wave Heights by Two-Frequency Cross-Correlation Function of Reflected Signals of a Spaceborne Radar Altimeter with Nadir Synthesis of Antenna Aperture

    NASA Astrophysics Data System (ADS)

    Ka, Min-Ho; Baskakov, Aleksandr I.; Terekhov, Vladimir A.

    In the work we introduce novel approach to remote sensing from space for the estimation of sea wave heights with a spaceborne high precision two-frequency radar altimeter with nadir synthesis antenna aperture. Experiments show considerable reduction of the decorrelation factor of the correlation coefficient and so significant enhancement of the sensitivity of the altimeter for the estimation for the sea wave status.

  5. 'Magic Angle Precession'

    SciTech Connect

    Binder, Bernd

    2008-01-21

    An advanced and exact geometric description of nonlinear precession dynamics modeling very accurately natural and artificial couplings showing Lorentz symmetry is derived. In the linear description it is usually ignored that the geometric phase of relativistic motion couples back to the orbital motion providing for a non-linear recursive precession dynamics. The high coupling strength in the nonlinear case is found to be a gravitomagnetic charge proportional to the precession angle and angular velocity generated by geometric phases, which are induced by high-speed relativistic rotations and are relevant to propulsion technologies but also to basic interactions. In the quantum range some magic precession angles indicating strong coupling in a phase-locked chaotic system are identified, emerging from a discrete time dynamical system known as the cosine map showing bifurcations at special precession angles relevant to heavy nuclei stability. The 'Magic Angle Precession' (MAP) dynamics can be simulated and visualized by cones rolling in or on each other, where the apex and precession angles are indexed by spin, charge or precession quantum numbers, and corresponding magic angles. The most extreme relativistic warping and twisting effect is given by the Dirac spinor half spin constellation with 'Hyperdiamond' MAP, which resembles quark confinement.

  6. PSA nadir predicts biochemical and distant failures after external beam radiotherapy for prostate cancer: A multi-institutional analysis

    SciTech Connect

    Ray, Michael E. . E-mail: mray@umich.edu; Thames, Howard D.; Levy, Larry B.; Horwitz, Eric M.; Kupelian, Patrick A.; Martinez, Alvaro A.; Michalski, Jeff M.; Pisansky, Thomas M.; Shipley, William U.; Zelefsky, Michael J.; Zietman, Anthony L.; Kuban, Deborah A.

    2006-03-15

    Purpose: To determine the significance of prostate-specific antigen (PSA) nadir (nPSA) and the time to nPSA (T{sub nPSA}) in predicting biochemical or clinical disease-free survival (PSA-DFS) and distant metastasis-free survival (DMFS) in patients treated with definitive external beam radiotherapy (RT) for clinical Stage T1b-T2 prostate cancer. Methods and Materials: Nine participating institutions submitted data on 4839 patients treated between 1986 and 1995 for Stage T1b-T2cN0-NxM0 prostate cancer. All patients were treated definitively with RT alone to doses {>=}60 Gy, without neoadjuvant or planned adjuvant androgen suppression. A total of 4833 patients with a median follow-up of 6.3 years met the criteria for analysis. Two endpoints were considered: (1) PSA-DFS, defined as freedom from PSA failure (American Society for Therapeutic Radiology and Oncology definition), initiation of androgen suppression after completion of RT, or documented local or distant failure; and (2) DMFS, defined as freedom from clinically apparent distant failure. In patients with failure, nPSA was defined as the lowest PSA measurement before any failure. In patients without failure, nPSA was the lowest PSA measurement during the entire follow-up period. T{sub nPSA} was calculated from the completion of RT to the nPSA date. Results: A greater nPSA level and shorter T{sub nPSA} were associated with decreased PSA-DFS and DMFS in all patients and in all risk categories (low [Stage T1b, T1c, or T2a, Gleason score {<=}6, and PSA level {<=}10 ng/mL], intermediate [Stage T1b, T1c, or T2a, Gleason score {<=}6, and PSA level >10 but {<=}20 ng/mL, or Stage T2b or T2c, Gleason score {<=}6, and PSA level {<=}20 ng/mL, or Gleason score 7 and PSA level {<=}20 ng/mL], and high [Gleason score 8-10 or PSA level >20 ng/mL]), regardless of RT dose. The 8-year PSA-DFS and DMFS rate for patients with nPSA <0.5 ng/mL was 75% and 97%; nPSA {>=}0.5 but <1.0 ng/mL, 52% and 96%; nPSA {>=}1.0 but <2.0 ng/mL, 40

  7. External Beam Radiotherapy for Clinically Localized Hormone-Refractory Prostate Cancer: Clinical Significance of Nadir Prostate-Specific Antigen Value Within 12 Months

    SciTech Connect

    Ogawa, Kazuhiko Nakamura, Katsumasa; Sasaki, Tomonari; Onishi, Hiroshi; Koizumi, Masahiko; Shioyama, Yoshiyuki; Araya, Masayuki; Mukumoto, Nobutaka M.S.; Mitsumori, Michihide; Teshima, Teruki

    2009-07-01

    Purpose: To analyze retrospectively the results of external beam radiotherapy for clinically localized hormone-refractory prostate cancer and investigate the clinical significance of nadir prostate-specific antigen (PSA) value within 12 months (nPSA12) as an early estimate of clinical outcomes after radiotherapy. Methods and Materials: Eighty-four patients with localized hormone-refractory prostate cancer treated with external beam radiotherapy were retrospectively reviewed. The total radiation doses ranged from 30 to 76 Gy (median, 66 Gy), and the median follow-up period for all 84 patients was 26.9 months (range, 2.7-77.3 months). Results: The 3-year actuarial overall survival, progression-free survival (PFS), and local control rates in all 84 patients after radiotherapy were 67%, 61%, and 93%, respectively. Although distant metastases and/or regional lymph node metastases developed in 34 patients (40%) after radiotherapy, local progression was observed in only 5 patients (6%). Of all 84 patients, the median nPSA12 in patients with clinical failure and in patients without clinical failure was 3.1 ng/mL and 0.5 ng/mL, respectively. When dividing patients according to low (<0.5 ng/mL) and high ({>=}0.5 ng/mL) nPSA12 levels, the 3-year PFS rate in patients with low nPSA12 and in those with high nPSA12 was 96% and 44%, respectively (p < 0.0001). In univariate analysis, nPSA12 and pretreatment PSA value had a significant impact on PFS, and in multivariate analysis nPSA12 alone was an independent prognostic factor for PFS after radiotherapy. Conclusions: External beam radiotherapy had an excellent local control rate for clinically localized hormone-refractory prostate cancer, and nPSA12 was predictive of clinical outcomes after radiotherapy.

  8. A Clinical Study of Mandibular Angle Fracture

    PubMed Central

    Yoon, Wook-Jae; Kim, Su-Gwan; Oh, Ji-Su; You, Jae-Seek; Lim, Kyung-Seop; Shin, Seung-Min; Kim, Cheol-Man

    2014-01-01

    Purpose: To establish management protocol for mandibular angle fracture, we describe pertinent factors including cause, impacted third molar and recent treatment tendency. Methods: We examined the records of 62 patients who had unilateral mandibular angle fracture. Sixty patients who had open reduction surgery were examined at postoperative weeks 1, 4, 8, 12, and 28. Results: Left mandibular angle fracture is frequent in younger males. Presence of the mandibular third molar can increase fracture risk. Because of attached muscle, favorable fractures occurred primarily in the mandibular angle area. Conclusion: Extracting the mandibular third molar can prevent angle fractures, and open reduction with only one plate adaptation is generally the proper treatment method for mandibular angle fracture. PMID:27489834

  9. Signature extension for sun angle, volume 1

    NASA Technical Reports Server (NTRS)

    Smith, J. A. (Principal Investigator); Berry, J. K.; Heimes, F.

    1975-01-01

    The author has identified the following significant results. Within a restricted zenith sun angle range of 35 - 50 degrees, it was empirically observed that canopy reflectance is mainly Lambertian. Reflectance changes with crop stage were simple shifts in scale in the sun angle range. It was noted that sun angle variations depend on canopy characteristics. Effects of the vegetative canopy were most pronounced at the larger solar zenith angles (20 %). The linear sun angle correction coefficients demonstrate a dependency on both crop stage (15-20 %) and crop type (10-20 %). The use of canopy reflectance modeling allowed for the generation of a simulated data set over an extremely broad envelope of sun angles.

  10. Sensitivity of thermal infrared nadir instruments to the chemical and microphysical properties of UTLS secondary sulfate aerosols

    NASA Astrophysics Data System (ADS)

    Sellitto, P.; Legras, B.

    2016-01-01

    Monitoring upper-tropospheric-lower-stratospheric (UTLS) secondary sulfate aerosols and their chemical and microphysical properties from satellite nadir observations is crucial to better understand their formation and evolution processes and then to estimate their impact on UTLS chemistry, and on regional and global radiative balance. Here we present a study aimed at the evaluation of the sensitivity of thermal infrared (TIR) satellite nadir observations to the chemical composition and the size distribution of idealised UTLS sulfate aerosol layers. The extinction properties of sulfuric acid/water droplets, for different sulfuric acid mixing ratios and temperatures, are systematically analysed. The extinction coefficients are derived by means of a Mie code, using refractive indices taken from the GEISA (Gestion et Étude des Informations Spectroscopiques Atmosphériques: Management and Study of Spectroscopic Information) spectroscopic database and log-normal size distributions with different effective radii and number concentrations. IASI (Infrared Atmospheric Sounding Interferometer) pseudo-observations are generated using forward radiative transfer calculations performed with the 4A (Automatized Atmospheric Absorption Atlas) radiative transfer model, to estimate the impact of the extinction of idealised aerosol layers, at typical UTLS conditions, on the brightness temperature spectra observed by this satellite instrument. We found a marked and typical spectral signature of these aerosol layers between 700 and 1200 cm-1, due to the absorption bands of the sulfate and bisulfate ions and the undissociated sulfuric acid, with the main absorption peaks at 1170 and 905 cm-1. The dependence of the aerosol spectral signature to the sulfuric acid mixing ratio, and effective number concentration and radius, as well as the role of interfering parameters like the ozone, sulfur dioxide, carbon dioxide and ash absorption, and temperature and water vapour profile uncertainties

  11. Analysis of stratospheric NO2 trends above Jungfraujoch using ground-based UV-visible, FTIR, and satellite nadir observations

    NASA Astrophysics Data System (ADS)

    Hendrick, F.; Mahieu, E.; Bodeker, G. E.; Boersma, K. F.; Chipperfield, M. P.; De Mazière, M.; De Smedt, I.; Demoulin, P.; Fayt, C.; Hermans, C.; Kreher, K.; Lejeune, B.; Pinardi, G.; Servais, C.; Stübi, R.; van der A, R.; Vernier, J.-P.; Van Roozendael, M.

    2012-05-01

    The trend in stratospheric NO2 column at the NDACC (Network for the Detection of Atmospheric Composition Change) station of Jungfraujoch (46.5° N, 8.0° E) is assessed using ground-based FTIR and zenith-scattered visible sunlight SAOZ measurements over the period 1990 to 2009 as well as a composite satellite nadir data set constructed from ERS-2/GOME, ENVISAT/SCIAMACHY, and METOP-A/GOME-2 observations over the 1996-2009 period. To calculate the trends, a linear least squares regression model including explanatory variables for a linear trend, the mean annual cycle, the quasi-biennial oscillation (QBO), solar activity, and stratospheric aerosol loading is used. For the 1990-2009 period, statistically indistinguishable trends of -3.7 ± 1.1%/decade and -3.6 ± 0.9%/decade are derived for the SAOZ and FTIR NO2 column time series, respectively. SAOZ, FTIR, and satellite nadir data sets show a similar decrease over the 1996-2009 period, with trends of -2.4 ± 1.1%/decade, -4.3 ± 1.4%/decade, and -3.6 ± 2.2%/decade, respectively. The fact that these declines are opposite in sign to the globally observed +2.5%/decade trend in N2O, suggests that factors other than N2O are driving the evolution of stratospheric NO2 at northern mid-latitudes. Possible causes of the decrease in stratospheric NO2 columns have been investigated. The most likely cause is a change in the NO2/NO partitioning in favor of NO, due to a possible stratospheric cooling and a decrease in stratospheric chlorine content, the latter being further confirmed by the negative trend in the ClONO2 column derived from FTIR observations at Jungfraujoch. Decreasing ClO concentrations slows the NO + ClO → NO2 + Cl reaction and a stratospheric cooling slows the NO + O3 → NO2 + O2 reaction, leaving more NOx in the form of NO. The slightly positive trends in ozone estimated from ground- and satellite-based data sets are also consistent with the decrease of NO2 through the NO2 + O3 → NO3 + O2 reaction. Finally

  12. Analysis of stratospheric NO2 trends above Jungfraujoch using ground-based UV-visible, FTIR, and satellite nadir observations

    NASA Astrophysics Data System (ADS)

    Hendrick, F.; Mahieu, E.; Bodeker, G. E.; Boersma, K. F.; Chipperfield, M. P.; De Mazière, M.; De Smedt, I.; Demoulin, P.; Fayt, C.; Hermans, C.; Kreher, K.; Lejeune, B.; Pinardi, G.; Servais, C.; Stübi, R.; van der A, R.; Vernier, J.-P.; Van Roozendael, M.

    2012-09-01

    The trend in stratospheric NO2 column at the NDACC (Network for the Detection of Atmospheric Composition Change) station of Jungfraujoch (46.5° N, 8.0° E) is assessed using ground-based FTIR and zenith-scattered visible sunlight SAOZ measurements over the period 1990 to 2009 as well as a composite satellite nadir data set constructed from ERS-2/GOME, ENVISAT/SCIAMACHY, and METOP-A/GOME-2 observations over the 1996-2009 period. To calculate the trends, a linear least squares regression model including explanatory variables for a linear trend, the mean annual cycle, the quasi-biennial oscillation (QBO), solar activity, and stratospheric aerosol loading is used. For the 1990-2009 period, statistically indistinguishable trends of -3.7 ± 1.1% decade-1 and -3.6 ± 0.9% decade-1 are derived for the SAOZ and FTIR NO2 column time series, respectively. SAOZ, FTIR, and satellite nadir data sets show a similar decrease over the 1996-2009 period, with trends of -2.4 ± 1.1% decade-1, -4.3 ± 1.4% decade-1, and -3.6 ± 2.2% decade-1, respectively. The fact that these declines are opposite in sign to the globally observed +2.5% decade-1 trend in N2O, suggests that factors other than N2O are driving the evolution of stratospheric NO2 at northern mid-latitudes. Possible causes of the decrease in stratospheric NO2 columns have been investigated. The most likely cause is a change in the NO2/NO partitioning in favor of NO, due to a possible stratospheric cooling and a decrease in stratospheric chlorine content, the latter being further confirmed by the negative trend in the ClONO2 column derived from FTIR observations at Jungfraujoch. Decreasing ClO concentrations slows the NO + ClO → NO2 + Cl reaction and a stratospheric cooling slows the NO + O3 → NO2 + O2 reaction, leaving more NOx in the form of NO. The slightly positive trends in ozone estimated from ground- and satellite-based data sets are also consistent with the decrease of NO2 through the NO2 + O3 → NO3 + O2

  13. Tropical tropospheric ozone columns from nadir retrievals of GOME-1/ERS-2, SCIAMACHY/Envisat, and GOME-2/MetOp-A (1996-2012)

    NASA Astrophysics Data System (ADS)

    Leventidou, Elpida; Eichmann, Kai-Uwe; Weber, Mark; Burrows, John P.

    2016-07-01

    Tropical tropospheric ozone columns are retrieved with the convective cloud differential (CCD) technique using total ozone columns and cloud parameters from different European satellite instruments. Monthly-mean tropospheric column amounts [DU] are calculated by subtracting the above-cloud ozone column from the total column. A CCD algorithm (CCD_IUP) has been developed as part of the verification algorithm developed for TROPOspheric Monitoring Instrument (TROPOMI) on Sentinel 5-precursor (S5p) mission, which was applied to GOME/ERS-2 (1995-2003), SCIAMACHY/Envisat (2002-2012), and GOME-2/MetOp-A (2007-2012) measurements. Thus a unique long-term record of monthly-mean tropical tropospheric ozone columns (20° S-20° N) from 1996 to 2012 is now available. An uncertainty estimation has been performed, resulting in a tropospheric ozone column uncertainty less than 2 DU ( < 10 %) for all instruments. The dataset has not been yet harmonised into one consistent; however, comparison between the three separate datasets (GOME/SCIAMACHY/GOME-2) shows that GOME-2 overestimates the tropical tropospheric ozone columns by about 8 DU, while SCIAMACHY and GOME are in good agreement. Validation with Southern Hemisphere ADditional OZonesondes (SHADOZ) data shows that tropospheric ozone columns from the CCD_IUP technique and collocated integrated ozonesonde profiles from the surface up to 200 hPa are in good agreement with respect to range, interannual variations, and variances. Biases within ±5 DU and root-mean-square (RMS) deviation of less than 10 DU are found for all instruments. CCD comparisons using SCIAMACHY data with tropospheric ozone columns derived from limb/nadir matching have shown that the bias and RMS deviation are within the range of the CCD_IUP comparison with the ozonesondes. The 17-year dataset can be helpful for evaluating chemistry models and performing climate change studies.

  14. Influences of twilight on diurnal variation of core temperature, its nadir, and urinary 6-hydroxymelatonin sulfate during nocturnal sleep and morning drowsiness.

    PubMed

    Kondo, Masayuki; Tokura, Hiromi; Wakamura, Tomoko; Hyun, Ki-Ja; Tamotsu, Satoshi; Morita, Takeshi; Oishi, Tadashi

    2009-03-01

    This study aimed at elucidating the physiological significance of dusk and dawn in the circadian rhythm of core temperature (T(core)) and urinary 6-hydroxymelatonin sulfate in humans during sleep and the waking sensation just after rising. Seven female and four male students served as participants. Participants retired at 2300 h and rose at 0700 h. They were requested to sit on a chair and spend time as quietly as possible during wakefulness, reading a book or listening to recorded light music. Two lighting conditions were provided for each participant: 1) Light-Dark (LD)-rectangular light change with abrupt decrease from 3,000 lx to 100 lx at 1800 h, abrupt increase from 0 lx to 3,000 lx at 0700 h. 2) LD-twilight light change with gradual decrease from 3,000 lx to 100 lx starting at 1700 h (twilight period about 2 h), with gradual increase from 0 lx to 3,000 lx starting at 0500 h (twilight period about 2 h). The periods of 0 lx at night were from 2300 h to 0700 h on the first day and from 2300 to 0500 h on the second day. Nadir time advanced significantly under the influence of the LD-twilight condition. The amount of 6-hydroxymelatonin sulfate in urine collected at 0200 h was significantly higher under LD-twilight in comparison with LD-rectangular light. Morning drowsiness tended to be lower under LD-twilight. Our results suggest that in architectural design of indoor illumination it is important to provide LD-twilight in the evening and early morning for sleep promotion in healthy normal people and/or light treatment in elderly patients with advanced dementia. PMID:19408625

  15. Extreme-Risk Prostate Adenocarcinoma Presenting With Prostate-Specific Antigen (PSA) >40 ng/ml: Prognostic Significance of the Preradiation PSA Nadir

    SciTech Connect

    Alexander, Abraham S.; Mydin, Aminudin; Jones, Stuart O.; Christie, Jennifer; Lim, Jan T.W.; Truong, Pauline T.; Ludgate, Charles M.

    2011-12-01

    Purpose: To examine the impact of patient, disease, and treatment characteristics on survival outcomes in patients treated with neoadjuvant androgen deprivation therapy (ADT) and radical external-beam radiotherapy (RT) for clinically localized, extreme-risk prostate adenocarcinoma with a presenting prostate-specific antigen (PSA) concentration of >40 ng/ml. Methods and Materials: A retrospective chart review was conducted of 64 patients treated at a single institution between 1991 and 2000 with ADT and RT for prostate cancer with a presenting PSA level of >40 ng/ml. The effects of patient age, tumor (presenting PSA level, Gleason score, and T stage), and treatment (total ADT duration and pre-RT PSA level) characteristics on rates of biochemical disease-free survival (bDFS), prostate cancer-specific survival (PCSS), and overall survival (OS) were examined. Results: Median follow-up time was 6.45 years (range, 0.09-15.19 years). Actuarial bDFS, PCSS, and OS rates at 5 years were 39%, 87%, and 78%, respectively, and 17%, 64%, and 45%, respectively, at 10 years. On multivariate analysis, the pre-RT PSA level ({<=}0.1 versus >0.1 ng/ml) was the single most significant prognostic factor for bDFS (p = 0.033) and OS (p = 0.018) rates, whereas age, T stage, Gleason score, and ADT duration ({<=}6 versus >6 months) were not predictive of outcomes. Conclusion: In prostate cancer patients with high presenting PSA levels, >40 ng/ml, treated with combined modality, neoadjuvant ADT, and RT, the pre-RT PSA nadir, rather than ADT duration, was significantly associated with improved survival. This observation supports the use of neoadjuvant ADT to drive PSA levels to below 0.1 ng/ml before initiation of RT, to optimize outcomes for patients with extreme-risk disease.

  16. Tree branch angle: maximizing effective leaf area.

    PubMed

    Honda, H; Fisher, J B

    1978-02-24

    In a computer simulation of branching pattern and leaf cluster in Terminalia catappa, right and left branch angles were varied, and the effective leaf surface areas were calculated. Theoretical branch angles that result in maximum effective leaf area are close to the values observed in nature. PMID:17757590

  17. Concurrent Measurements of the PMC mass on the Limb and in the Nadir: New Constraints on Hemispheric Asymmetries

    NASA Astrophysics Data System (ADS)

    Stevens, M. H.; Englert, C. R.; Bailey, S. M.; Deland, M. T.

    2006-05-01

    Recent satellite observations suggest that polar mesospheric clouds (PMCs) occur more frequently and are brighter in the north compared to the south. However, a determination of how much more ice is present in the north requires a more direct standard of measurement. The PMC ice mass, calculated using both the PMC occurrence frequency and brightness, is one such standard. The PMC mass is a useful quantity for interpreting observations of solar backscattered light (θ>90°) from PMCs because it is relatively insensitive to variations in characteristics of the ice particle size distribution, used to compute the ice mass column from the cloud brightness. The Student Nitric Oxide Explorer (SNOE) and the Solar Backscatter Ultraviolet (SBUV) instruments simultaneously measured solar backscattered light from PMCs in both hemispheres between 1998-2003. SNOE observed PMCs on the limb while SBUV has observed PMCs in the nadir every year since 1979. Using data from the same latitudes (70±2.5°) and local times, we compare the PMC mass observed by both instruments in both hemispheres. Ice particle radii inferred from simultaneous measurements at three SBUV wavelengths in the mid-UV are greater than 80 nm in both hemispheres. These radii are larger than those typically inferred from more sensitive limb-viewing instruments such as SNOE, providing new constraints for global-scale climate models.

  18. A Nadir-adjusted Airborne Multi Spectral Imaging System (NAMSIS) for high-resolution remote sensing of carbon fluxes

    NASA Astrophysics Data System (ADS)

    Jiang, Z.; Scott, S.; Rahman, A. F.

    2012-12-01

    Satellite remote sensing is widely used in vegetation monitoring, water stress detection and carbon cycle modeling. However, image pixels from high temporal resolution satellite sensors (such as MODIS) have coarse spatial resolution, much larger than the canopies they are supposed to characterize. An alternative solution for on-demand high spatial resolution remote sensing is sensors onboard low-flying aircrafts. Airborne remote sensing has been traditionally used in crop management studies. In this presentation we demonstrate the application of a relatively low-cost airborne sensor system with customized spectral band combinations for studying forest carbon fluxes. Our team has developed an Inertia Measurement Unit (IMU) controlled automated system to detach aircraft movements (pitch and roll) and engine vibration from the six-band programmable imager, in order to maintain the sensor at nadir view at all times during the flight. Flight lines are configured by a GPS-controleld system to simulate MODIS pixels. A feature-based algorithm is used to automatically generate a mosaic of individual images along the flight lines. This algorithm eliminates the need to mosiac and georeference images manually. An empirical line method is used to calculate reflectance from the raw data. Images from this airborne system produce reflectance values that are comparable with MODIS reflectance product. These high spatial resolution (~0.5 m) images deliver detailed information about tree species and phenological conditions within each MODIS pixel, and thus permit a high resolution spatio-temporal assessment of forest carbon fluxes.

  19. An Iterative Angle Trisection

    ERIC Educational Resources Information Center

    Muench, Donald L.

    2007-01-01

    The problem of angle trisection continues to fascinate people even though it has long been known that it can't be done with straightedge and compass alone. However, for practical purposes, a good iterative procedure can get you as close as you want. In this note, we present such a procedure. Using only straightedge and compass, our procedure…

  20. Casting and Angling.

    ERIC Educational Resources Information Center

    Little, Mildred J.; Bunting, Camille

    The self-contained packet contains background information, lesson plans, 15 transparency and student handout masters, drills and games, 2 objective examinations, and references for teaching a 15-day unit on casting and angling to junior high and senior high school students, either as part of a regular physical education program or as a club…

  1. The Rainbow Angle.

    ERIC Educational Resources Information Center

    Sims, B.

    1978-01-01

    Two articles in the "Scientific American" form the background of this note. The rainbow angle for the primary bow of a monochromatic Cartesian rainbow is calculated. Special projects for senior high school students could be patterned after this quantitative study. (MP)

  2. Casting and Angling.

    ERIC Educational Resources Information Center

    Smith, Julian W.

    As part of a series of books and pamphlets on outdoor education, this manual consists of easy-to-follow instructions for fishing activities dealing with casting and angling. The manual may be used as a part of the regular physical education program in schools and colleges or as a club activity for the accomplished weekend fisherman or the…

  3. Yaw Angle Demonstration

    NASA Technical Reports Server (NTRS)

    1994-01-01

    The Large Angle Magnetic Suspension Test Fixture (LAMSTF) is a 5 degree-of -freedom repulsive force magnetic suspension system designed to study the control of objects over large magnetic gaps. A digital control algorithm uses 6 sets of laser-sheet sensors and 5 control coils to position a cylinder 3' above the plane of electromagnetics

  4. Measurements of terrestrial IR radiation by a medium-angle receiver

    NASA Astrophysics Data System (ADS)

    Korneeva, L. V.; Priakhin, E. A.

    Measurements of terrestrial IR radiation by a medium-angle nonscanning single-channel radiometer with spectral sensitivity of 0.3-30 microns, energy band of the measured brightnesses of 63-250 W/sq m sr, accuracy of better than 1 percent, and viewing angle of 45 deg are analyzed. The instrument, based on the Meteor-2 satellite, is nadir-oriented and covers a spot 680 km in diameter. The measurements are divided into three longitudinal regions (145 deg W, 120 deg W, and 90 deg E); a considerable drop in registered radiation is noted in the 30-50 deg N region. It is indicated that the lowest fluxes were registered in both hemispheres, as compared with data available for the longwave region, with the differences not exceeding 2.5 percent in the presence of clouds and 7 percent otherwise.

  5. Detecting blind building façades from highly overlapping wide angle aerial imagery

    NASA Astrophysics Data System (ADS)

    Burochin, Jean-Pascal; Vallet, Bruno; Brédif, Mathieu; Mallet, Clément; Brosset, Thomas; Paparoditis, Nicolas

    2014-10-01

    This paper deals with the identification of blind building façades, i.e. façades which have no openings, in wide angle aerial images with a decimeter pixel size, acquired by nadir looking cameras. This blindness characterization is in general crucial for real estate estimation and has, at least in France, a particular importance on the evaluation of legal permission of constructing on a parcel due to local urban planning schemes. We assume that we have at our disposal an aerial survey with a relatively high stereo overlap along-track and across-track and a 3D city model of LoD 1, that can have been generated with the input images. The 3D model is textured with the aerial imagery by taking into account the 3D occlusions and by selecting for each façade the best available resolution texture seeing the whole façade. We then parse all 3D façades textures by looking for evidence of openings (windows or doors). This evidence is characterized by a comprehensive set of basic radiometric and geometrical features. The blindness prognostic is then elaborated through an (SVM) supervised classification. Despite the relatively low resolution of the images, we reach a classification accuracy of around 85% on decimeter resolution imagery with 60 × 40 % stereo overlap. On the one hand, we show that the results are very sensitive to the texturing resampling process and to vegetation presence on façade textures. On the other hand, the most relevant features for our classification framework are related to texture uniformity and horizontal aspect and to the maximal contrast of the opening detections. We conclude that standard aerial imagery used to build 3D city models can also be exploited to some extent and at no additional cost for facade blindness characterisation.

  6. Divergent-ray projection method for measuring the flapping angle, lag angle, and torsional angle of a bumblebee wing

    NASA Astrophysics Data System (ADS)

    Zeng, Lijiang; Matsumoto, Hirokazu; Kawachi, Keiji

    1996-11-01

    A divergent-ray projection (DRP) method was developed for measuring the flapping angle, lag angle, and torsional angle of bumblebee wing during beating motion. This new method can measure the spatial coordinates of an insect wing by digitizing the images that are projected by two divergent laser rays from different directions. The advantage of the DRP method is its ability to measure those three angles simultaneously using only one high-speed camera. The resolution of the DRP method can be changed easily by adjusting system parameters to meet the needs of different types of objects. The measurement results for these angles of a bumblebee wing probe the effectiveness of the DRP method in studying the flight performance of insects.

  7. On the effect of emergence angle on emissivity spectra: application to small bodies

    NASA Astrophysics Data System (ADS)

    Maturilli, Alessandro; Helbert, Jörn; Ferrari, Sabrina; D'Amore, Mario

    2016-05-01

    Dependence of laboratory-measured emissivity spectra from the emergence angle is a subject that still needs a lot of investigations to be fully understood. Most of the previous work is based on reflectance measurements in the VIS-NIR spectral region and on emissivity measurements of flat, solid surfaces (mainly metals), which are not directly applicable to the analysis of remote sensing data. Small bodies in particular (c.f. asteroids Itokawa and 1999JU3, the respective targets of JAXA Hayabusa and Hayabusa 2 missions) have a very irregular surface; hence, the spectra from those rough surfaces are difficult to compare with laboratory spectra, where the observing geometry is always close to "nadir." At the Planetary Emissivity Laboratory of the German Aerospace Center (DLR), we have set up a series of spectral measurements to investigate this problem in the 1- to 16-µm spectral region. We measured the emissivity for two asteroid analogue materials (meteorite Millbillillie and a synthetic enstatite) in vacuum and under purged air, at surface temperature of 100 °C, for emergence angles of 0°, 5°, 10°, 20°, 30°, 40°, 50°, and 60°. Emissivity of a serpentinite slab, already used as calibration target for the MARA instrument on Hayabusa 2 MASCOT lander and for the thermal infrared imager spectrometer on Hayabusa 2 orbiter, was measured under the same conditions. Additionally, a second basalt slab was measured. Both slabs were not measured at 5° inclination. Complementary reflectance measurements of the four samples were taken. For all the samples measured, we found that for calibrated emissivity, significant variations from values obtained at nadir (0° emergence angle) appear only for emergence angles ≥40°. Reflectance measurements confirmed this finding, showing the same trend of variations.

  8. Dose to specific subregions of pelvic bone marrow defined with FDG-PET as a predictor of hematologic nadirs during concomitant chemoradiation in anal cancer patients.

    PubMed

    Franco, Pierfrancesco; Arcadipane, Francesca; Ragona, Riccardo; Lesca, Adriana; Gallio, Elena; Mistrangelo, Massimiliano; Cassoni, Paola; Arena, Vincenzo; Bustreo, Sara; Faletti, Riccardo; Rondi, Nadia; Morino, Mario; Ricardi, Umberto

    2016-07-01

    To test the hypothesis that irradiated volume of specific subregions of pelvic active bone marrow as detected by (18)FDG-PET may be a predictor of decreased blood cells nadirs in anal cancer patients undergoing concurrent chemoradiation, we analyzed 44 patients submitted to IMRT and concurrent chemotherapy. Several bony structures were defined: pelvic and lumbar-sacral (LSBM), lower pelvis (LPBM) and iliac (IBM) bone marrow. Active BM was characterized employing (18)FDG-PET and characterized in all subregions as the volume having standard uptake values (SUVs) higher than SUVmean. All other regions were defined as inactive BM. On dose-volume histograms, dosimetric parameters were taken. Endpoints included white blood cell count (WBC), absolute neutrophil count (ANC), hemoglobin (Hb) and platelet (Plt) nadirs. Generalized linear modeling was used to find correlations between dosimetric variables and blood cells nadirs. WBC nadir was significantly correlated with LSBM mean dose (β = -1.852; 95 % CI -3.205/-0.500; p = 0.009), V10 (β = -2.153; 95 % CI -4.263/-0.721; p = 0.002), V20 (β = -2.081; 95 % CI -4.880/-0.112; p = 0.003), V30 (β = -1.971; 95 % CI -4.748/-0.090; p = 0.023) and IBM V10 (β = -0.073; 95 % CI -0.106/-0.023; p = 0.016). ANC nadir found to be significantly associated with LSBM V10 (β = -1.878; 95 % CI -4.799/-0.643; p = 0.025), V20 (β = -1.765; 95 % CI -4.050/-0.613; p = 0.030) and IBM V10 (β = -0.039; 95 % CI -0.066/-0.010; p = 0.027). Borderline significance was found for correlation between Plt nadir and LSBM V30 (β = -0.056; 95 % CI -2.748/-0.187; p = 0.060), V40 (β = -0.059; 95 % CI -3.112/-0.150; p = 0.060) and IBM V30 (β = -0.028; 95 % CI -0.074/-0.023; p = 0.056). No inactive BM subsites were found to be correlated with any blood cell nadir. (18)FDG-PET is able to define active bone marrow within pelvic osseous structures. LSBM is the strongest predictor of decreased blood cells

  9. Supercritical Angle Fluorescence Correlation Spectroscopy

    PubMed Central

    Ries, Jonas; Ruckstuhl, Thomas; Verdes, Dorinel; Schwille, Petra

    2008-01-01

    We explore the potential of a supercritical angle (SA) objective for fluorescence correlation spectroscopy (FCS). This novel microscope objective combines tight focusing by an aspheric lens with strong axial confinement of supercritical angle fluorescence collection by a parabolic mirror lens, resulting in a small detection volume. The tiny axial extent of the detection volume features an excellent surface sensitivity, as is demonstrated by diffusion measurements in model membranes with an excess of free dye in solution. All SA-FCS measurements are directly compared to standard confocal FCS, demonstrating a clear advantage of SA-FCS, especially for diffusion measurements in membranes. We present an extensive theoretical framework that allows for accurate and quantitative evaluation of the SA-FCS correlation curves. PMID:17827221

  10. A Different Angle on Perspective

    ERIC Educational Resources Information Center

    Frantz, Marc

    2012-01-01

    When a plane figure is photographed from different viewpoints, lengths and angles appear distorted. Hence it is often assumed that lengths, angles, protractors, and compasses have no place in projective geometry. Here we describe a sense in which certain angles are preserved by projective transformations. These angles can be constructed with…

  11. A method for merging nadir-sounding climate records, with an application to the global-mean stratospheric temperature data sets from SSU and AMSU

    NASA Astrophysics Data System (ADS)

    McLandress, C.; Shepherd, T. G.; Jonsson, A. I.; von Clarmann, T.; Funke, B.

    2015-08-01

    A method is proposed for merging different nadir-sounding climate data records using measurements from high-resolution limb sounders to provide a transfer function between the different nadir measurements. The two nadir-sounding records need not be overlapping so long as the limb-sounding record bridges between them. The method is applied to global-mean stratospheric temperatures from the NOAA Climate Data Records based on the Stratospheric Sounding Unit (SSU) and the Advanced Microwave Sounding Unit-A (AMSU), extending the SSU record forward in time to yield a continuous data set from 1979 to present, and providing a simple framework for extending the SSU record into the future using AMSU. SSU and AMSU are bridged using temperature measurements from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), which is of high enough vertical resolution to accurately represent the weighting functions of both SSU and AMSU. For this application, a purely statistical approach is not viable since the different nadir channels are not sufficiently linearly independent, statistically speaking. The near-global-mean linear temperature trends for extended SSU for 1980-2012 are -0.63 ± 0.13, -0.71 ± 0.15 and -0.80 ± 0.17 K decade-1 (95 % confidence) for channels 1, 2 and 3, respectively. The extended SSU temperature changes are in good agreement with those from the Microwave Limb Sounder (MLS) on the Aura satellite, with both exhibiting a cooling trend of ~ 0.6 ± 0.3 K decade-1 in the upper stratosphere from 2004 to 2012. The extended SSU record is found to be in agreement with high-top coupled atmosphere-ocean models over the 1980-2012 period, including the continued cooling over the first decade of the 21st century.

  12. Measurement of Peak Esophageal Luminal Cross Sectional Area Utilizing Nadir Intraluminal Impedance

    PubMed Central

    Zifan, Ali; Ledgerwood-Lee, Melissa; Mittal, Ravinder K

    2015-01-01

    BACKGROUND Multichannel intraluminal impedance (MII) is currently used to monitor gastroesophageal reflux and esophageal bolus clearance. We describe a novel methodology to measure maximal luminal CSA during bolus transport from MII measurements. METHODS Studies were conducted in-vitro (test tubes) and in-vivo (healthy subjects). Concurrent MII, HRM, and intraluminal ultrasound (US) were recorded 7 cm above the lower esophageal sphincter. Swallows with two concentrations of saline, 0.1N and 0.5N, of bolus volumes 5cc, 10cc and 15cc were performed. The CSA was estimated by solving two algebraic Ohm’s law equations, resulting from the two saline solutions. The CSA calculated from impedance method was compared with the CSA measured from the intraluminal US images. KEY RESULTS The CSA measured in duplicate from B-mode US images showed a mean difference between the two manual delineations to be near zero, and the repeatability coefficient was within 7.7% of the mean of the two CSA measurements. The calculated CSA from the impedance measurements strongly correlated with the US measured CSA (R2 ≅ 0.98). A detailed statistical analysis of the impedance and US measured CSA data indicated that the 95% limits of agreement between the two methods ranged from −9.1 to 13mm2. The root mean square error (RMS) of the two measurements was 4.8% of the mean US-measured CSA. CONCLUSIONS We describe a novel methodology to measure peak esophageal luminal CSA during peristalsis. Further studies are needed to determine if it is possible to measure patterns of luminal distension during peristalsis across the entire length of the esophagus. PMID:25930157

  13. Angles in the Sky?

    NASA Astrophysics Data System (ADS)

    Behr, Bradford

    2005-09-01

    Tycho Brahe lived and worked in the late 1500s before the telescope was invented. He made highly accurate observations of the positions of planets, stars, and comets using large angle-measuring devices of his own design. You can use his techniques to observe the sky as well. For example, the degree, a common unit of measurement in astronomy, can be measured by holding your fist at arm's length up to the sky. Open your fist and observe the distance across the sky covered by the width of your pinky fingernail. That is, roughly, a degree! After some practice, and knowing that one degree equals four minutes, you can measure elapsed time by measuring the angle of the distance that the Moon appears to have moved and multiplying that number by four. You can also figure distances and sizes of things. These are not precise measurements, but rough estimates that can give you a "close-enough" answer.

  14. Laser angle sensor

    NASA Technical Reports Server (NTRS)

    Pond, C. R.; Texeira, P. D.

    1985-01-01

    A laser angle measurement system was designed and fabricated for NASA Langley Research Center. The instrument is a fringe counting interferometer that monitors the pitch attitude of a model in a wind tunnel. A laser source and detector are mounted above the model. Interference fringes are generated by a small passive element on the model. The fringe count is accumulated and displayed by a processor in the wind tunnel control room. This report includes optical and electrical schematics, system maintenance and operation procedures.

  15. Angle states in quantum mechanics

    NASA Astrophysics Data System (ADS)

    de la Torre, A. C.; Iguain, J. L.

    1998-12-01

    Angle states and angle operators are defined for a system with arbitrary angular momentum. They provide a reasonable formalization of the concept of angle provided that we accept that the angular orientation is quantized. The angle operator is the generator of boosts in angular momentum and is, almost everywhere, linearly related to the logarithm of the shift operator. Angle states for fermions and bosons behave differently under parity transformation.

  16. Experimental study of crossing angle collision

    SciTech Connect

    Chen, T.; Rice, D.; Rubin, D.; Sagan, D.; Tigner, M.

    1993-05-01

    The non-linear coupling due to the beam-beam interaction with crossing angle has been studied. The major effect of a small ({approximately}12mrad) crossing angle is to excite 5Q{sub x}{plus_minus}Q{sub s}=integer coupling resonance family on large amplitude particles, which results in bad lifetime. On the CESR, a small crossing angle ({approximately}2.4mr) was created at the IP and a reasonable beam-beam tune-shift was achieved. The decay rate of the beam is measured as a function of horizontal tune with and without crossing angle. The theoretical analysis, simulation and experimental measurements have a good agreement. The resonance strength as a function of crossing angle is also measured.

  17. Later endogenous circadian temperature nadir relative to an earlier wake time in older people

    NASA Technical Reports Server (NTRS)

    Duffy, J. F.; Dijk, D. J.; Klerman, E. B.; Czeisler, C. A.

    1998-01-01

    The contribution of the circadian timing system to the age-related advance of sleep-wake timing was investigated in two experiments. In a constant routine protocol, we found that the average wake time and endogenous circadian phase of 44 older subjects were earlier than that of 101 young men. However, the earlier circadian phase of the older subjects actually occurred later relative to their habitual wake time than it did in young men. These results indicate that an age-related advance of circadian phase cannot fully account for the high prevalence of early morning awakening in healthy older people. In a second study, 13 older subjects and 10 young men were scheduled to a 28-h day, such that they were scheduled to sleep at many circadian phases. Self-reported awakening from scheduled sleep episodes and cognitive throughput during the second half of the wake episode varied markedly as a function of circadian phase in both groups. The rising phase of both rhythms was advanced in the older subjects, suggesting an age-related change in the circadian regulation of sleep-wake propensity. We hypothesize that under entrained conditions, these age-related changes in the relationship between circadian phase and wake time are likely associated with self-selected light exposure at an earlier circadian phase. This earlier exposure to light could account for the earlier clock hour to which the endogenous circadian pacemaker is entrained in older people and thereby further increase their propensity to awaken at an even earlier time.

  18. Wide Angle Movie

    NASA Technical Reports Server (NTRS)

    1999-01-01

    This brief movie illustrates the passage of the Moon through the Saturn-bound Cassini spacecraft's wide-angle camera field of view as the spacecraft passed by the Moon on the way to its closest approach with Earth on August 17, 1999. From beginning to end of the sequence, 25 wide-angle images (with a spatial image scale of about 14 miles per pixel (about 23 kilometers)were taken over the course of 7 and 1/2 minutes through a series of narrow and broadband spectral filters and polarizers, ranging from the violet to the near-infrared regions of the spectrum, to calibrate the spectral response of the wide-angle camera. The exposure times range from 5 milliseconds to 1.5 seconds. Two of the exposures were smeared and have been discarded and replaced with nearby images to make a smooth movie sequence. All images were scaled so that the brightness of Crisium basin, the dark circular region in the upper right, is approximately the same in every image. The imaging data were processed and released by the Cassini Imaging Central Laboratory for Operations (CICLOPS)at the University of Arizona's Lunar and Planetary Laboratory, Tucson, AZ.

    Photo Credit: NASA/JPL/Cassini Imaging Team/University of Arizona

    Cassini, launched in 1997, is a joint mission of NASA, the European Space Agency and Italian Space Agency. The mission is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Space Science, Washington DC. JPL is a division of the California Institute of Technology, Pasadena, CA.

  19. Perceptions of tilt angles of an agricultural tractor.

    PubMed

    Görücü, Serap; Cavallo, Eugenio; Murphy, Dennis

    2014-01-01

    A tractor stability simulator has been developed to help study tractor operators' perceptions of angles when the simulator is tilted to the side. The simulator is a trailer-mounted tractor cab equipped with hydraulic lift that can tilt the tractor cabin up to 30 degrees. This paper summarizes data from 82 participants who sat in the simulator while it was tilted. Demographic variables, estimates of tilt angles, and measured tilt angles were collected. The effects of age, gender, tractor driving experience, and frequency of operation on the estimated and measured tilt angles were analyzed. The results showed that about 50% of the participants reported estimations of side tilt angles within ±5 degrees of the actual angles, and nearly the same percentage overestimated the actual side tilt angles. Only a small percentage underestimated the angles. Older, more experienced, and male participants set higher limits on the actual angle at which they felt uncomfortable and would not drive. PMID:24417527

  20. Angle amplifier based on multiplexed volume holographic gratings

    NASA Astrophysics Data System (ADS)

    Cao, Liangcai; Zhao, Yifei; He, Qingsheng; Jin, Guofan

    2008-03-01

    Angle amplifier of laser beam scanner is a widely used device in optical systems. Volume holographic optical elements can be applied in the angle amplifier. Compared with the traditional angle amplifier, it has the advantages of high angle resolution, high diffraction efficiency, small size, and high angle magnification and flexible design. Bragg anglewavelength- compensating recording method is introduced. Because of the Bragg compensatory relation between angle and wavelength, this device could be recorded at another wavelength. The design of the angle amplifier recording at the wavelength of 514.2nm for the working wavelength of 632.8nm is described. An optical setup for recording the angle amplifier device is designed and discussed. Experimental results in the photorefractive crystal Fe:LiNbO 3 demonstrate the feasibility of the angle amplifier scheme.

  1. Study on self-calibration angle encoder using simulation method

    NASA Astrophysics Data System (ADS)

    Wang, Yan; Xue, Zi; Huang, Yao; Wang, Xiaona

    2016-01-01

    The angle measurement technology is very important in precision manufacture, optical industry, aerospace, aviation and navigation, etc. Further, the angle encoder, which uses concept `subdivision of full circle (2π rad=360°)' and transforms the angle into number of electronic pulse, is the most common instrument for angle measurement. To improve the accuracy of the angle encoder, a novel self-calibration method was proposed that enables the angle encoder to calibrate itself without angle reference. An angle deviation curve among 0° to 360° was simulated with equal weights Fourier components for the study of the self-calibration method. In addition, a self-calibration algorithm was used in the process of this deviation curve. The simulation result shows the relationship between the arrangement of multi-reading heads and the Fourier components distribution of angle encoder deviation curve. Besides, an actual self-calibration angle encoder was calibrated by polygon angle standard in national institute of metrology, China. The experiment result indicates the actual self-calibration effect on the Fourier components distribution of angle encoder deviation curve. In the end, the comparison, which is between the simulation self-calibration result and the experiment self-calibration result, reflects good consistency and proves the reliability of the self-calibration angle encoder.

  2. Skylab S-193 radar altimeter experiment analyses and results

    NASA Technical Reports Server (NTRS)

    Brown, G. S. (Editor)

    1977-01-01

    The design of optimum filtering procedures for geoid recovery is discussed. Statistical error bounds are obtained for pointing angle estimates using average waveform data. A correlation of tracking loop bandwidth with magnitude of pointing error is established. The impact of ocean currents and precipitation on the received power are shown to be measurable effects. For large sea state conditions, measurements of sigma 0 deg indicate a distinct saturation level of about 8 dB. Near-nadir less than 15 deg values of sigma 0 deg are also presented and compared with theoretical models. Examination of Great Salt Lake Desert scattering data leads to rejection of a previously hypothesized specularly reflecting surface. Pulse-to-pulse correlation results are in agreement with quasi-monochromatic optics theoretical predictions and indicate a means for estimating direction of pointing error. Pulse compression techniques for and results of estimating significant waveheight from waveform data are presented and are also shown to be in good agreement with surface truth data. A number of results pertaining to system performance are presented.

  3. Variable angle correlation spectroscopy

    SciTech Connect

    Lee, Y K

    1994-05-01

    In this dissertation, a novel nuclear magnetic resonance (NMR) technique, variable angle correlation spectroscopy (VACSY) is described and demonstrated with {sup 13}C nuclei in rapidly rotating samples. These experiments focus on one of the basic problems in solid state NMR: how to extract the wealth of information contained in the anisotropic component of the NMR signal while still maintaining spectral resolution. Analysis of the anisotropic spectral patterns from poly-crystalline systems reveal information concerning molecular structure and dynamics, yet in all but the simplest of systems, the overlap of spectral patterns from chemically distinct sites renders the spectral analysis difficult if not impossible. One solution to this problem is to perform multi-dimensional experiments where the high-resolution, isotropic spectrum in one dimension is correlated with the anisotropic spectral patterns in the other dimensions. The VACSY technique incorporates the angle between the spinner axis and the static magnetic field as an experimental parameter that may be incremented during the course of the experiment to help correlate the isotropic and anisotropic components of the spectrum. The two-dimensional version of the VACSY experiments is used to extract the chemical shift anisotropy tensor values from multi-site organic molecules, study molecular dynamics in the intermediate time regime, and to examine the ordering properties of partially oriented samples. The VACSY technique is then extended to three-dimensional experiments to study slow molecular reorientations in a multi-site polymer system.

  4. Longitudinal Changes of Angle Configuration in Primary Angle-Closure Suspects

    PubMed Central

    Jiang, Yuzhen; Chang, Dolly S.; Zhu, Haogang; Khawaja, Anthony P.; Aung, Tin; Huang, Shengsong; Chen, Qianyun; Munoz, Beatriz; Grossi, Carlota M.

    2015-01-01

    Objective To determine longitudinal changes in angle configuration in the eyes of primary angle-closure suspects (PACS) treated by laser peripheral iridotomy (LPI) and in untreated fellow eyes. Design Longitudinal cohort study. Participants Primary angle-closure suspects aged 50 to 70 years were enrolled in a randomized, controlled clinical trial. Methods Each participant was treated by LPI in 1 randomly selected eye, with the fellow eye serving as a control. Angle width was assessed in a masked fashion using gonioscopy and anterior segment optical coherence tomography (AS-OCT) before and at 2 weeks, 6 months, and 18 months after LPI. Main Outcome Measures Angle width in degrees was calculated from Shaffer grades assessed under static gonioscopy. Angle configuration was also evaluated using angle opening distance (AOD250, AOD500, AOD750), trabecular-iris space area (TISA500, TISA750), and angle recess area (ARA) measured in AS-OCT images. Results No significant difference was found in baseline measures of angle configuration between treated and untreated eyes. At 2 weeks after LPI, the drainage angle on gonioscopy widened from a mean of 13.5° at baseline to a mean of 25.7° in treated eyes, which was also confirmed by significant increases in all AS-OCT angle width measures (P<0.001 for all variables). Between 2 weeks and 18 months after LPI, a significant decrease in angle width was observed over time in treated eyes (P<0.001 for all variables), although the change over the first 5.5 months was not statistically significant for angle width measured under gonioscopy (P = 0.18), AOD250 (P = 0.167) and ARA (P = 0.83). In untreated eyes, angle width consistently decreased across all follow-up visits after LPI, with a more rapid longitudinal decrease compared with treated eyes (P values for all variables ≤0.003). The annual rate of change in angle width was equivalent to 1.2°/year (95% confidence interval [CI], 0.8–1.6) in treated eyes and 1.6°/year (95% CI, 1

  5. A Note on Angle Construction

    ERIC Educational Resources Information Center

    Francis, Richard L.

    1978-01-01

    The author investigates the construction of angles (using Euclidean tools) through a numerical approach. He calls attention to the surprising impossibility of constructing the conventional units of angle measure--the degree, minute, second, radian, and mil. (MN)

  6. Prostate-specific antigen nadir after high-dose-rate brachytherapy predicts long-term survival outcomes in high-risk prostate cancer

    PubMed Central

    Satoh, Takefumi; Ishiyama, Hiromichi; Tabata, Ken-ichi; Komori, Shouko; Sekiguchi, Akane; Ikeda, Masaomi; Kurosaka, Shinji; Fujita, Tetsuo; Kitano, Masashi; Hayakawa, Kazushige; Iwamura, Masatsugu

    2016-01-01

    Purpose To evaluate the prognostic value of prostate-specific antigen nadir (nPSA) after high-dose-rate (HDR) brachytherapy in clinically non-metastatic high-risk prostate cancer patients. Material and methods Data from 216 patients with high-risk or locally advanced prostate cancer who underwent HDR brachytherapy and external beam radiation therapy with long-term androgen deprivation therapy (ADT) between 2003 and 2008 were analyzed. The median prostate-specific antigen (PSA) level at diagnosis was 24 ng/ml (range: 3-338 ng/ml). The clinical stage was T1c-2a in 55 cases (26%), T2b-2c in 48 (22%), T3a in 75 (35%), and T3b-4 in 38 (17%). The mean dose to 90% of the planning target volume was 6.3 Gy/fraction of HDR brachytherapy. After 5 fractions, external beam radiation therapy with 10 fractions of 3 Gy was administered. All patients initially underwent neoadjuvant ADT for at least 6 months, and adjuvant ADT was continued for 36 months. The median follow-up was 7 years from the start of radiotherapy. Results The 7-year PSA relapse-free rate among patients with a post-radiotherapy nPSA level of ≤ 0.02 ng/ml was 94%, compared with 23% for patients with higher nPSA values (HR = 28.57; 95% CI: 12.04-66.66; p < 0.001). Multivariate analysis revealed that the nPSA value after radiotherapy was a significant independent predictor of biochemical failure, whereas pretreatment predictive values for worse biochemical control including higher level of initial PSA, Gleason score ≥ 8, positive biopsy core rate ≥ 67%, and T3b-T4, failed to reach independent predictor status. The 7-year cancer-specific survival rate among patients with a post-radiotherapy nPSA level of ≤ 0.02 ng/ml was 99%, compared with 82% for patients with higher nPSA values (HR = 32.25; 95% CI: 3.401-333.3; p = 0.002). Conclusions A post-radiotherapy nPSA value of ≤ 0.02 ng/ml was associated with better long-term biochemical tumor control even if patients had pretreatment predictive values for worse

  7. Meridional Distribution of CH3C2H and C4H2 in Saturn's Stratosphere from CIRS/Cassini Limb and Nadir Observations

    NASA Technical Reports Server (NTRS)

    Guerlet, Sandrine; Fouchet, Thierry; Bezard, Bruno; Moses, Julianne I.; Fletcher, Leigh N.; Simon-Miller, Amy A.; Flasar, F. Michael

    2010-01-01

    Limb and nadir spectra acquired by Cassini/CIRS (Composite InfraRed Spectrometer) are analyzed in order to derive, for the first time, the meridional variations of diacetylene (C4H2) and methylacetylene (CH3C2H) mixing ratios in Saturn's stratosphere, from 5 hPa up to 0.05 hPa and 80 deg S to 45 deg N. We find that the C4H2 and CH3C2H meridional distributions mimic that of acetylene (C2H2), exhibiting small-scale variations that are not present in photochemical model predictions. The most striking feature of the meridional distribution of both molecules is an asymmetry between mid-southern and mid-northern latitudes. The mid-southern latitudes are found depleted in hydrocarbons relative to their northern counterparts. In contrast, photochemical models predict similar abundances at north and south mid-latitudes. We favor a dynamical explanation for this asymmetry, with upwelling in the south and downwelling in the north, the latter coinciding with the region undergoing ring shadowing. The depletion in hydrocarbons at mid-southern latitudes could also result from chemical reactions with oxygen-bearing molecules. Poleward of 60 deg S, at 0.1 and 0.05 hPa, we find that the CH3C2H and C4H2 abundances increase dramatically. This behavior is in sharp contradiction with photochemical model predictions, which exhibit a strong decrease towards the south pole. Several processes could explain our observations, such as subsidence, a large vertical eddy diffusion coefficient at high altitudes, auroral chemistry that enhances CH3C2H and C4H2 production, or shielding from photolysis by aerosols or molecules produced from auroral chemistry. However, problems remain with all these hypotheses, including the lack of similar behavior at lower altitudes. Our derived mean mixing ratios at 0.5 hPa of (2.4 +/- 0.3) 10(exp -10) for C4H2 and of (1.1 +/- 0.3) 10(exp -9) for CH3C2H are compatible with the analysis of global-average ISO observations performed by Moses et al. Finally, we provide

  8. Utilizing the US Lab Nadir Research Window for Remote Sensing Operations with The Window Observational Research Facility (WORF)

    NASA Technical Reports Server (NTRS)

    Turner, Richard; Barley, Bryan; Gilbert, Paul A. (Technical Monitor)

    2002-01-01

    The Window Observational Research Facility (WORF) is an ISPR-based rack facility designed to take advantage of the high optical quality US Lab Nadir research window. The WORF is based on the ISS Expedite the Processing of Experiments to Space Station (EXPRESS) rack mechanical structure and electronic systems. The WORF has a unique payload volume located at the center of the rack that provides access to the window. The interior dimensions of the payload volume are 34-in. (86.36 cm) wide by 33-in. (83.82 cm) high by 23-in. (58.42 cm) deep. This facility supports the deployment of payloads such as 9 in. aerial photography cameras and 12 in. diameter optical equipment. The WORF coupled with the optical quality of the United States Lab window support the deployment of various payload disciplines. The WORF provides payloads with power, data command and control, air cooling, water cooling, and video processing. The WORF's payload mounting surfaces and interfaces include the interior payload mounting shelf and the interior and exterior aircraft-like seat tracks. The payload mounting shelf is limited to a maximum mass of 136 kg (299 pounds). The WORF can accommodate large payloads such as the commonly used Leica-Heerbrug RC-30 aerial photography camera (whose dimensions are 53.3 cm (21-in.) wide by 50.8 cm (20-in.) deep by 76.2 cm (30-in.) long). The performance characteristics of the WORF allow it to support an array of payload disciplines. The WORF provides a maximum of 3 Kw at 28 Vdc and has a maximum data rate of 10 Mbps. The WORF's unique payload volume is designed to be light-tight, down to 2.8 x 10(exp -11) Watts/cm2/steradian, and have low-reflective surfaces. This specially designed WORF interior supports payload investigations that observe low-light-level phenomenon such as aurora. Although the WORF rack does not employ any active rack isolation (i.e., vibration dampening) technology, the rack provides a very stable environment for payload operations (on the order

  9. High-resolution solid air gapped etalon in the 9500-nm region: application for nadir remote sounding of tropospheric ozone

    NASA Astrophysics Data System (ADS)

    Kumer, John B.; Rairden, Richard L.; Roche, Aidan E.; Mergenthaler, John L.; Naes, Lawrence G., Jr.; Jamieson, Thomas H.; Stephen, Thomas

    2003-03-01

    We present test data for a solid ZnSe air gapped etalon with free spectral range 3 cm-1 and finesse >70 (i.e., spectral resolution <0.043 cm-1). We present an instrument concept, the Tropopsheric Ozone Sounding (TOS) Dual Etalon Cross Tilt Order Sorting Spectrometer (DECTOSS), that would use an etalon like this to acquire nadir data at resolution <0.06 cm-1 and signal to noise the order 1000 on a range from 1036 to 1071 cm-1 in footprints with crosstrack dimension selectable (e.g., the order tens to hundreds of km), and with along track dimension the order 17 km. Instrument accommodation is the order 25 kg, 110 W and 1 mbps. We present linear error analysis for retrieval of tropospheric ozone from the data acquired by the TOS-DECTOSS. Indication is that more than 2.5 vertical layers of information on tropospheric information are retrievable. An example of the deployment of the TOS-DECTOSS would be as an instrument of opportunity (IOO) add on to the US National Polar-orbiting Operational Environmental Satellite System (NPOESS). The huge advantage of the TOS-DECTOSS as compared with UV techniques for tropospheric ozone measurement is that it the can be used both day and night, the latter is not possible in the UV. The considerable advantage in signal to noise compared with a Fourier Transform Spectrometer (FTS) for tropospheric ozone measurement, on considering that for a given footprint the DECTOSS and FTS integration times are comparable, is that the DECTOSS noise per spectral sample is dominated by statistical fluctuations of signal photons that are passed through its narrow 0.06 cm-1 bandpass, while for a similar FTS spectral sample the noise is due to fluctuations of the signal photons through the FTS bandpass of tens of cm-1. The TOS-DECTOSS signal to noise advantage on the FTS is also enhanced in that the spectral sample density of the TOS-DECTOSS data is more than one hundred times larger than for the FTS.

  10. Angle only tracking with particle flow filters

    NASA Astrophysics Data System (ADS)

    Daum, Fred; Huang, Jim

    2011-09-01

    We show the results of numerical experiments for tracking ballistic missiles using only angle measurements. We compare the performance of an extended Kalman filter with a new nonlinear filter using particle flow to compute Bayes' rule. For certain difficult geometries, the particle flow filter is an order of magnitude more accurate than the EKF. Angle only tracking is of interest in several different sensors; for example, passive optics and radars in which range and Doppler data are spoiled by jamming.