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On identifying the specular reflection of sunlight in earth-monitoring satellite data.

Description: Among the background signals commonly seen by Earth-monitoring satellites is the specular reflection of sunlight off of Earth's surface, commonly referred to as a glint. This phenomenon, involving liquid or ice surfaces, can result in the brief, intense illumination of satellite sensors appearing from the satellite perspective to be of terrestrial origin. These glints are important background signals to be able to identify with confidence, particularly in the context of analyzing data from satellites monitoring for transient surface or atmospheric events. Here we describe methods for identifying glints based on the physical processes involved in their production, including spectral fitting and polarization measurements. We then describe a tool that, using the WGS84 spheroidal Earth model, finds the latitude and longitude on Earth where a reflection of this type could be produced, given input Sun and satellite coordinates. This tool enables the user to determine if the surface at the solution latitude and longitude is in fact reflective, thus identifying the sensor response as a true glint or an event requiring further analysis.
Date: March 1, 2009
Creator: Nelsen, James M., Jr.; Hohlfelder, Robert James; Jackson, Dale Clayton & Longenbaugh, Randolph S.
Partner: UNT Libraries Government Documents Department

Data Format Standards for Civilian Remote Sensing Satellites

Description: This report discusses the earth data—positional, topographic, climatological, meteorological, man–made features, and changes over time in all of these, which are increasingly important to the military. Data from these systems are bought and extensively used by the military and intelligence communities. The need to integrate data from military-unique systems as well only complicates the situation.
Date: May 1993
Creator: United States. Congress. Office of Technology Assessment.
Partner: UNT Libraries Government Documents Department

The Future of Remote Sensing From Space: Civilian Satellite Systems and Applications

Description: This report examines issues related to the development and operation of publicly funded U.S. and foreign civilian remote sensing systems. It also explores the military and intelligence use of data gathered by civilian satellites. In addition, the report examines the outlook for privately funded and operated remote sensing systems.
Date: July 1993
Creator: United States. Congress. Office of Technology Assessment.
Partner: UNT Libraries Government Documents Department

In-situ FPGA debug driven by on-board microcontroller

Description: Often we are faced with the situation that the behavior of a circuit changes in an unpredictable way when chassis cover is attached or the system is not easily accessible. For instance, in a deployed environment, such as space, hardware can malfunction in unpredictable ways. What can a designer do to ascertain the cause of the problem? Register interrogations only go so far, and sometimes the problem being debugged is register transactions themselves, or the problem lies in FPGA programming. This work provides a solution to this; namely, the ability to drive a JTAG chain via an on-board microcontroller and use a simple clone of the Xilinx Chipscope core without a Xilinx JTAG cable or any external interfaces required. We have demonstrated the functionality of the prototype system using a Xilinx Spartan 3E FPGA and a Microchip PIC18j2550 microcontroller. This paper will discuss the implementation details as well as present case studies describing how the tools have aided satellite hardware development.
Date: January 1, 2009
Creator: Baker, Zachary Kent
Partner: UNT Libraries Government Documents Department

Radiation load to the SNAP CCD

Description: Results of an express Monte Carlo analysis with the MARS14 code of radiation load to the CCD optical detectors in the Supernova Acceleration Project (SNAP) mission presented for realistic radiation environment over the satellite orbit.
Date: August 14, 2003
Creator: N. V. Mokhov, I. L. Rakhno and S. I. Striganov
Partner: UNT Libraries Government Documents Department

Bigfoot Field Manual, Version 2.1

Description: The BigFoot Project is funded by the Earth Science Enterprise to collect and organize data to be used in the National Aeronautics and Space Administration's Earth Observing System (EOS) Validation Program. The data collected by the BigFoot Project are unique in being ground-based observations coincident with satellite overpasses. In addition to collecting data, the BigFoot project will develop and test new algorithms for scaling point measurements to the same spatial scales as the EOS satellite products. This BigFoot Field Manual will be used to achieve completeness and consistency of data collected at four initial BigFoot sites and at future sites that may collect similar validation data. Therefore, validation datasets submitted to the Oak Ridge National Laboratory Distributed Active Archive Center that have been compiled in a manner consistent with the field manual will be especially valuable in the validation program.
Date: September 1, 1999
Creator: Campbell, J.L.; Burrows, S.; Gower, S.T. & Cohen, W.B.
Partner: UNT Libraries Government Documents Department

Final Report of Research Conducted For DE-AI02-08ER64546

Description: Research was conducted for 3-4 years to use ARM data to validate satellite cloud retrievals and help the development of improved techniques for remotely sensing clouds and radiative fluxes from space to complement the ARM surface measurement program. This final report summarizes the results and publications during the last 2 years of the studies. Since our last report covering the 2009 period, we published four papers that were accepted during the previous reporting period and revised and published a fifth one. Our efforts to intercalibrate selected channels on several polar orbiting and geostationary satellite imagers, which are funded in part by ASR, resulted in methods that were accepted as part of the international Global Space-based Intercalibration System (GSICS) calibration algorithms. We developed a new empirical method for correcting the spectral differences between comparable channels on various imagers that will be used to correct the calibrations of the satellite data used for ARM. We documented our cloud retrievals for the VAMOS Ocean-Cloud-Atmosphere-Land Study Regional Experiment (VOCALS-Rex; ARM participated with an AAF contribution) in context of the entire experiment. We used our VOCALS satellite data along with the aircraft measurements to better understand the relationships between aerosols and liquid water path in marine stratus clouds. We continued or efforts to validate and improve the satellite cloud retrievals for ARM and using ARM data to validate retrievals for other purposes.
Date: March 28, 2012
Creator: Minnis, Patrick
Partner: UNT Libraries Government Documents Department

Evidence for Merging or Disruption of Red Galaxies from the Evolution of Their Clustering

Description: The formation and evolution of massive red galaxies form a crucial test of theories of galaxy formation based on hierarchical assembly. In this Letter we use observations of the clustering of luminous red galaxies from the Boötes field and N-body simulations to argue that about of the most luminous satellite galaxies appear to undergo merging or disruption within massive halos between and 0.5.
Date: November 29, 2006
Creator: White, Martin; White, Martin; Zheng, Zheng; Brown, Michael J. I.; Dey, Arjun & Jannuzi, Buell T.
Partner: UNT Libraries Government Documents Department

Southern Great Plains Newsletter, September 2010

Description: Monthly newsletter of Argonne National Laboratory. This month's issue contains the following articles: (1) Scientists convene at SGP site for complex convective cloud experiment; (2) VORTEX2 spins down; (3) Sunphotometer supports SPARTICUS (a Sun and Aureole Measurement imaging sunphotometer) campaign and satellite validation studies; and (4) Ceilometer represents first deployment of new ground-based instruments from Recovery Act.
Date: September 2010
Creator: Argonne National Laboratory
Partner: UNT Libraries Government Documents Department

Making Maps from Planck LFI 30GHz Data with Asymmetric Beams and Cooler Noise

Description: The Planck satellite will observe the full sky at nine frequencies from 30 to 857 GHz. Temperature and polarization frequency maps made from these observations are prime deliverables of the Planck mission. The goal of this paper is to examine the effects of four realistic instrument systematics in the 30 GHz frequency maps: non-axially-symmetric beams, sample integration, sorption cooler noise, and pointing errors. They simulated one year long observations of four 30 GHz detectors. The simulated timestreams contained CMB, foreground component (both galactic and extra-galactic), instrument nolise (correlated and white), and the four instrument systematic effects. They made maps from the timelines and examined the magnitudes of the systematics effects in the maps and their angular power spectra. They also compared the maps of different mapmaking codes to see how they performed. They used five mapmaking codes (two destripers and three optimal codes). None of their mapmaking codes makes an attempt to deconvolve the beam from its output map. Therefore all our maps had similar smoothing due to beams and sample integration. This is a complicated smoothing, because every map pixel has its own effective beam. Temperature to polarization cross-coupling due to beam mismatch causes a detectable bias in the TE spectrum of the CMB map. The effects of cooler noise and pointing errors did not appear to be major concerns for the 30 GHz channel. The only essential difference found so far between mapmaking codes that affects accuracy (in terms of residual RMS) is baseline length. All optimal codes give essentially indistiguishable results. A destriper gives the same result as the optimal codes when the baseline is set short enough (Madam). For longer baselines destripers (Springtide and Madam) require less computing resources but deliver a noisier map.
Date: June 19, 2008
Creator: Group, The Planck CTP Working; Ashdown, M.A.J.; Baccigalupi, C.; Bartlett, J.G.; Borrill, J.; Cantalupo, C. et al.
Partner: UNT Libraries Government Documents Department

Autonomous Sub-Pixel Satellite Track Endpoint Determination for Space Based Images

Description: An algorithm for determining satellite track endpoints with sub-pixel resolution in spaced-based images is presented. The algorithm allows for significant curvature in the imaged track due to rotation of the spacecraft capturing the image. The motivation behind the subpixel endpoint determination is first presented, followed by a description of the methodology used. Results from running the algorithm on real ground-based and simulated spaced-based images are shown to highlight its effectiveness.
Date: March 7, 2011
Creator: Simms, L M
Partner: UNT Libraries Government Documents Department

Estimation of Net Ecosystem Carbon Exchange for the Conterminous UnitedStates by Combining MODIS and AmeriFlux Data

Description: Eddy covariance flux towers provide continuous measurements of net ecosystem carbon exchange (NEE) for a wide range of climate and biome types. However, these measurements only represent the carbon fluxes at the scale of the tower footprint. To quantify the net exchange of carbon dioxide between the terrestrial biosphere and the atmosphere for regions or continents, flux tower measurements need to be extrapolated to these large areas. Here we used remotely-sensed data from the Moderate Resolution Imaging Spectrometer (MODIS) instrument on board NASA's Terra satellite to scale up AmeriFlux NEE measurements to the continental scale. We first combined MODIS and AmeriFlux data for representative U.S. ecosystems to develop a predictive NEE model using a regression tree approach. The predictive model was trained and validated using NEE data over the periods 2000-2004 and 2005-2006, respectively. We found that the model predicted NEE reasonably well at the site level. We then applied the model to the continental scale and estimated NEE for each 1 km x 1 km cell across the conterminous U.S. for each 8-day period in 2005 using spatially-explicit MODIS data. The model generally captured the expected spatial and seasonal patterns of NEE. Our study demonstrated that our empirical approach is effective for scaling up eddy flux NEE measurements to the continental scale and producing wall-to-wall NEE estimates across multiple biomes. Our estimates may provide an independent dataset from simulations with biogeochemical models and inverse modeling approaches for examining the spatiotemporal patterns of NEE and constraining terrestrial carbon budgets for large areas.
Date: March 6, 2009
Creator: Xiao, Jingfeng; Zhuang, Qianlai; Baldocchi, Dennis D.; Law, Beverly E.; Richardson, Andrew D.; Chen, Jiquan et al.
Partner: UNT Libraries Government Documents Department

Long-term slip rate of the southern San Andreas Fault, from 10Be-26Al surface exposure dating of an offset alluvial fan

Description: We determine the long-term slip rate of the southern San Andreas Fault in the southeastern Indio Hills using {sup 10}Be and {sup 26}Al isotopes to date an offset alluvial fan surface. Field mapping complemented with topographic data, air photos and satellite images allow to precisely determine piercing points across the fault zone that are used to measure an offset of 565 {+-} 80 m. A total of twenty-six quartz-rich cobbles from three different fan surfaces were collected and dated. The tight cluster of nuclide concentrations from 19 samples out of 20 from the offset fan surface implies a simple exposure history, negligible prior exposure and erosion, and yield an age of 35.5 {+-} 2.5 ka. The long-term slip rate of the San Andreas Fault south of Biskra Palms is thus 15.9 {+-} 3.4 mm/yr. This rate is about 10 mm/yr slower than geological (0-14 ka) and short-term geodetic estimates for this part of the San Andreas Fault implying changes in slip rate or in faulting behavior. This result puts new constraints on the slip rate of the San Jacinto and on the Eastern California Shear Zone for the last 35 ka. Our study shows that more sites along the major faults of southern California need to be targeted to better constrain the slip-rates over different time scales.
Date: January 13, 2006
Creator: der Woerd, J v; Klinger, Y; Sieh, K; Tapponnier, P; Ryerson, F & M?riaux, A
Partner: UNT Libraries Government Documents Department

Upper Limits on the Number of Small Bodies in Sedna-Like Orbits by the TAOS Project

Description: We present the results of a search for occultation events by objects at distances between 100 and 1000 AU in lightcurves from the Taiwanese-American Occultation Survey (TAOS). We searched for consecutive, shallow flux reductions in the stellar lightcurves obtained by our survey between 7 February 2005 and 31 December 2006 with a total of {approx} 4.5 x 10{sup 9} three-telescope simultaneous photometric measurements. No events were detected, allowing us to set upper limits on the number density as a function of size and distance of objects in Sedna-like orbits, using simple models.
Date: November 13, 2009
Creator: Wang, J; Lehner, M J; Zhang, Z; Bianco, F B; Alcock, C; Chen, W et al.
Partner: UNT Libraries Government Documents Department

Global optical lightning flash rates determined with the Forte satellite

Description: Using FORTE photodiode detector (PDD) observations of lightning, we have determined the geographic distribution of nighttime flash rate density. We estimate the PDD flash detection efficiency to be 62% for total lightning through comparison to lightning observations by the TRMM satellite's Lightning Imaging Sensor (LIS), using cases in which FORTE and TRMM viewed the same storm. We present here both seasonal and l,ot,al flash rate maps. We examine some characteristics of the optical emissions of lightning in both high and low flash rate environments, and find that while lightning occurs less frequently over ocean, oceanic lightning flashes are somewhat more powerful, on average, than those over land.
Date: January 1, 2003
Creator: Light, T. (Tracy E.); Davis, S. M. (Sean M.); Boeck, W. L. (William L.); Jacobson, A. R. & Suszcynsky, D. M. (David M.)
Partner: UNT Libraries Government Documents Department

Hubble Space Telescope: NASA's Plans for a Servicing Mission

Description: The National Aeronautics and Space Administration (NASA) estimates that without a servicing mission to replace key components, the Hubble Space Telescope will cease scientific operations in 2008. In January 2004, then-NASA Administrator Sean O'Keefe announced that the space shuttle would no longer be used to service Hubble. Hubble supporters criticized this as a result of President Bush's new Vision for Space Exploration; said supporters sought to reverse the decision and proceed with a shuttle servicing mission. In October 2006, NASA approved a shuttle mission to service Hubble. That mission is now scheduled for October 8, 2008.
Date: May 23, 2008
Creator: Morgan, Daniel
Partner: UNT Libraries Government Documents Department

Coherent beam-beam effects, theory & observations

Description: Current theoretical understanding of the coherent beam-beam effect as well as its experimental observations are discussed: conditions under which the coherent beambeam modes may appear, possibility of their resonant interaction (coherent resonances), stability of beam-beam oscillations in the presence of external impedances. A special attention is given to the coherent beam-beam modes of finite length bunches: the synchro-betatron coupling is shown to provide reduction in the coherent tuneshift and--at the synchrotron tune values smaller than the beam-beam parameter--Landau damping by overlapping synchrotron satellites.
Date: July 16, 2003
Creator: Alexahin, Yuri I
Partner: UNT Libraries Government Documents Department