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1

Satellite Observation Systems for Polar Climate Change Studies  

NASA Technical Reports Server (NTRS)

The key observational tools for detecting large scale changes of various parameters in the polar regions have been satellite sensors. The sensors include passive and active satellite systems in the visible, infrared and microwave frequencies. The monitoring started with Tiros and Nimbus research satellites series in the 1970s but during the period, not much data was stored digitally because of limitations and cost of the needed storage systems. Continuous global data came about starting with the launch of ocean color, passive microwave, and thermal infrared sensors on board Nimbus-7 and Synthetic Aperture Radar, Radar Altimeter and Scatterometer on board SeaSat satellite both launched in 1978. The Nimbus-7 lasted longer than expected and provided about 9 years of useful data while SeaSat quit working after 3 months but provided very useful data that became the baseline for follow-up systems with similar capabilities. Over the years, many new sensors were launched, some from Japan Aeronautics and Space Agency (JAXA), some from the European Space Agency (ESA) and more recently, from RuSSia, China, Korea, Canada and India. For polar studies, among the most useful sensors has been the passive microwave sensor which provides day/night and almost all weather observation of the surface. The sensor provide sea surface temperature, precipitation, wind, water vapor and sea ice concentration data that have been very useful in monitoring the climate of the region. More than 30 years of such data are now available, starting with the Scanning Multichannel Microwave Radiometer (SMMR) on board the Nimbus-7, the Special Scanning Microwave/Imager (SSM/I) on board a Defense Meteorological Satellite Program (DMSP) and the Advanced Microwave Scanning Radiometer on board the EOS/ Aqua satellite. The techniques that have been developed to derive geophysical parameters from data provided by these and other sensors and associated instrumental and algorithm errors and validation techniques will be discussed. An important issue is the organization and storage of hundreds of terabytes of data collected by even just a few of these satellite sensors. Advances in mass storage and computer technology have made it possible to overcome many of the collection and archival problems and the availability of comprehensive satellite data sets put together by NASA's Earth Observing System project will be discussed.

Comiso, Josefino C.

2012-01-01

2

Previous observations of mutual events of the Saturnian satellites and of other satellites systems.  

NASA Astrophysics Data System (ADS)

A concise analysis of the results of 1973, 1979, 1985 and 1991 campaigns of mutual events between Jupiter's satellites, of the 1980 campaign of mutual events between Saturn's satellites and of the campaign of mutual events between Pluto and Charon is presented. All the photoelectric observations of the presented mutual phenomena were carried out at Serra La Nave stellar station of Catania Astrophysical Observatory.

Blanco, C.

1996-02-01

3

NASDA's earth observation satellite data archive policy for the earth observation data and information system (EOIS)  

NASA Technical Reports Server (NTRS)

NASDA's new Advanced Earth Observing Satellite (ADEOS) is scheduled for launch in August, 1996. ADEOS carries 8 sensors to observe earth environmental phenomena and sends their data to NASDA, NASA, and other foreign ground stations around the world. The downlink data bit rate for ADEOS is 126 MB/s and the total volume of data is about 100 GB per day. To archive and manage such a large quantity of data with high reliability and easy accessibility it was necessary to develop a new mass storage system with a catalogue information database using advanced database management technology. The data will be archived and maintained in the Master Data Storage Subsystem (MDSS) which is one subsystem in NASDA's new Earth Observation data and Information System (EOIS). The MDSS is based on a SONY ID1 digital tape robotics system. This paper provides an overview of the EOIS system, with a focus on the Master Data Storage Subsystem and the NASDA Earth Observation Center (EOC) archive policy for earth observation satellite data.

Sobue, Shin-ichi; Yoshida, Fumiyoshi; Ochiai, Osamu

1996-01-01

4

Observations of outer planet satellites  

Microsoft Academic Search

A regular natural satellite observing program has been in operation at McDonald Observatory since late 1972. The observation type has been direct astrometric photography from which the positions of the satellites may be measured with respect to the background star field. Effort has been devoted to the satellite systems of Saturn, Uranus and Neptune as well as the faint outer

Peter J. Sheulus; Richard I. Abbot; J. Derral Mulholland

1975-01-01

5

Observations of Outer Planet Satellites  

Microsoft Academic Search

A regular natural satellite observing program has been in operation at McDonald Observatory since late 1972. The observation type has been direct astrometric photography from which the positions of the satellites may be measured with respect to the background star field. Effort has been devoted to the satellite systems of Saturn, Uranus and Neptune as well as the faint outer

Peter J. Sheulus; Richard I. Abbot; J. Derral Mulholland

1975-01-01

6

Earth observing satellite: Understanding the Earth as a system  

NASA Technical Reports Server (NTRS)

There is now a plan for global studies which include two very large efforts. One is the International Geosphere/Biosphere Program (IGBP) sponsored by the International Council of Scientific Unions. The other initiative is Mission to Planet Earth, an unbrella program for doing three kinds of space missions. The major one is the Earth Observation Satellite (EOS). EOS is large polar orbiting satellites with heavy payloads. Two will be placed in orbit by NASA, one by the Japanese and one or two by ESA. The overall mission measurement objectives of EOS are summarized: (1) the global distribution of energy input to and energy output from the Earth; (2) the structure, state variables, composition, and dynamics of the atmosphere from the ground to the mesopause; (3) the physical and biological structure, state, composition, and dynamics of the land surface, including terrestrial and inland water ecosystems; (4) the rates, important sources and sinks, and key components and processes of the Earth's biogeochemical cycles; (5) the circulation, surface temperature, wind stress, sea state, and the biological activity of the oceans; (6) the extent, type, state, elevation, roughness, and dynamics of glaciers, ice sheets, snow and sea ice, and the liquid equivalent of snow in the global cryosphere; (7) the global rates, amounts, and distribution of precipitation; and (8) the dynamic motions of the Earth (geophysics) as a whole, including both rotational dynamics and the kinematic motions of the tectonic plates.

Soffen, Gerald

1990-01-01

7

System architecting of a campaign of earth observing satellites  

E-print Network

Given the current level of concern over anthropogenic climate change, and the ongoing debate worldwide regarding what action should be taken to reduce and reverse future warming, the ability to collect data on Earth system ...

Colson, Justin M

2008-01-01

8

Candidate configuration trade study, Stellar-inertial Measurement Systems (SIMS) for an Earth Observation Satellite (EOS)  

NASA Technical Reports Server (NTRS)

The results of analytical and simulation studies of the stellar-inertial measurement system (SIMS) for an earth observation satellite are presented. Subsystem design analyses and sensor design trades are reported. Three candidate systems are considered: (1) structure-mounted gyros with structure-mounted star mapper, (2) structure-mounted gyros with gimbaled star tracker, and (3) gimbaled gyros with structure-mounted star mapper. The purpose of the study is to facilitate the decisions pertaining to gimbaled versus structure-mounted gyros and star sensors, and combinations of systems suitable for the EOS satellite.

Ogletree, G.; Coccoli, J.; Mckern, R.; Smith, M.; White, R.

1972-01-01

9

Moon revolving observation satellite  

Microsoft Academic Search

An overview of the conceptual study of the moon revolving observation satellites to be launched by the H-2 launch vehicle for lunar surface mapping and resources exploration from a polar orbit at an altitude of 100 km is presented. The results of the mission study, including the studies of mission requirements and mission equipment selection, and mission analysis including analyses

Reiji Katane; Tsuyoshi Okazaki

1992-01-01

10

Observing system simulation experiments to assess the potential impact of proposed satellite instruments on hurricane prediction  

NASA Astrophysics Data System (ADS)

Observing System Simulation Experiments (OSSEs) are an important tool for evaluating the potential impact of proposed new observing systems, as well as for evaluating trade-offs in observing system design, and in developing and assessing improved methodology for assimilating new observations. Extensive OSSEs have been conducted at NASA/ GSFC and NOAA/AOML over the last three decades. These OSSEs determined correctly the quantitative potential for several proposed satellite observing systems to improve weather analysis and prediction prior to their launch, evaluated trade-offs in orbits, coverage and accuracy for space-based wind lidars, and were used in the development of the methodology that led to the first beneficial impacts of satellite surface winds on numerical weather prediction. In this paper, we summarize early applications of global OSSEs to hurricane track forecasting and new experiments using both global and regional models. These experiments are aimed at determining (1) the potential impact of unmanned aerial systems, (2) the relative impact of alternative concepts for space-based lidar winds, and (3) the relative impact of alternative concepts for polar and geostationary hyperspectral sounders.

Atlas, Robert; Pagano, Thomas S.

2014-09-01

11

An analysis of the upper atmospheric wind observed by LOGACS. [satellite Low-G Accelerometer Calibration System  

NASA Technical Reports Server (NTRS)

Wind velocities at 140 to 200 km altitude were observed by a low-g accelerometer calibration system (LOGACS) flown on an Agena satellite during a geomagnetic storm. An interesting wind reversal observed by the satellite at auroral latitudes is satisfactorily explained by the neutral air motion caused by the E x B drift deduced from the ground-based geomagnetic data recorded at stations near the meridian of the satellite orbit.

Wu, S. T.; Matsushita, S.; Devries, L. L.

1974-01-01

12

Nonlinear Observer with Time-Varying Gains for Inertial Navigation Aided by Satellite Reference Systems in Dynamic Positioning  

E-print Network

Nonlinear Observer with Time-Varying Gains for Inertial Navigation Aided by Satellite Reference sensors. I. INTRODUCTION A strapdown inertial navigation system (INS) is mounted on a navigating object-- The measurement quality of Global Navigation Satellites Systems (GNSS) during marine operations will vary over

Johansen, Tor Arne

13

IR Spectrophotometric Observations of Geosynchronous Satellites  

NASA Astrophysics Data System (ADS)

We have observed several geosynchronous satellites at the Advanced Electro-Optical System (AEOS) 3.6 meter telescope, utilizing The Aerospace Corporation's Broadband Array Spectrograph System (BASS) 3-13 micron sensor, as well as the site's Hi-VIS 1-2.5 micron spectrograph. The various satellites show different trends with phase angle, which may allow satellite identification based on observables. Data were collected on several nights, on multiple satellites, and at various phase angles for each satellite. We describe our methods, our data, our analysis, and our results.

Skinner, M.; Payne, T.; Russell, R.; Gutierrez, D.; Crawford, K.; Harrington, D.; Kim, D.; Lynch, D.; Rudy, R.

14

The Effect of Satellite Observing System Changes on MERRA Water and Energy Fluxes  

NASA Technical Reports Server (NTRS)

Because reanalysis data sets offer state variables and fluxes at regular space / time intervals, atmospheric reanalyses have become a mainstay of the climate community for diagnostic purposes and for driving offline ocean and land models. Although one weakness of these data sets is the susceptibility of the flux products to uncertainties because of shortcomings in parameterized model physics, another issue, perhaps less appreciated, is the fact that continual but discreet changes in the evolving observational system, particularly from satellite sensors, may also introduce artifacts in the time series of quantities. In this paper we examine the ability of the NASA MERRA (Modern Era Retrospective Analysis for Research and Applications) and other recent reanalyses to determine variability in the climate system over the satellite record (approximately the last 30 years). In particular we highlight the effect on the reanalysis of discontinuities at the junctures of the onset of passive microwave imaging (Special Sensor Microwave Imager) in late 1987 as well as improved sounding and imaging with the Advanced Microwave Sounding Unit, AMSU-A, in 1998. We first examine MERRA fluxes from the perspective of how physical modes of variability (e.g. ENSO events, Pacific Decadal Variability) are contaminated by artificial step-like trends induced by the onset of new moisture data these two satellite observing systems. Secondly, we show how Redundancy Analysis, a statistical regression methodology, is effective in relating these artifact signals in the moisture and temperature analysis increments to their presence in the physical flux terms (e.g. precipitation, radiation). This procedure is shown to be effective greatly reducing the artificial trends in the flux quantities.

Robertson, Franklin R.; Bosilovich, M. G.; Chen, J.; Miller, t. L.

2010-01-01

15

The Effect of Satellite Observing System Changes on MERRA Water and Energy Fluxes  

NASA Technical Reports Server (NTRS)

Because reanalysis data sets offer state variables and fluxes at regular space / time intervals, atmospheric reanalyses have become a mainstay of the climate community for diagnostic purposes and for driving offline ocean and land models. Although one weakness of these data sets is the susceptibility of the flux products to uncertainties because of shortcomings in parameterized model physics, another issue, perhaps less appreciated, is the fact that continual but discreet changes in the evolving observational system, particularly from satellite sensors, may also introduce artifacts in the time series of quantities. In this paper we examine the ability of the NASA MERRA (Modern Era Retrospective Analysis for Research and Applications) and other recent reanalyses to determine variability in the climate system over the satellite record (approx. the last 30 years). In particular we highlight the effect on the reanalysis of discontinuities at the junctures of the onset of passive microwave imaging (Special Sensor Microwave Imager) in late 1987 and, more prominently, with improved sounding and imaging with the Advanced Microwave Sounding Unit, AMSU-A, in 1998. We first examine MERRA fluxes from the perspective of how physical modes of variability (e.g. ENSO events, Pacific Decadal Variability) are contained by artificial step-like trends induced by the onset of new moisture data these two satellite observing systems. Secondly, we show how Redundancy Analysis, a statistical regression methodology, is effective in relating these artifact signals in the moisture and temperature analysis increments to their presence in the physical flux terms (e.g. precipitation, radiation). This procedure is shown to be effective greatly reducing the artificial trends in the flux quantities.

Robertson, Franklin R.; Bosilovich, M. G.; Chen, J.; Miller, T. L.

2011-01-01

16

Dynamical and observational constraints on satellites in the inner Pluto-Charon system  

NASA Technical Reports Server (NTRS)

It is not known if Pluto has other satellites besides its massive partner Charon. In the past, searches for additional satellites in the Pluto-Charon system have extended from the solar-tidal stability boundary (approximately 90 arcsec from Pluto) inward to about 1 arcsec from Pluto. Here we further explore the inner (i.e., less than 10 arcsec) region of the Pluto-Charon system to determine where additional satellites might lie. In particular, we report on (1) dynamical simulations to delineate the region where unstable orbits lie around Charon, (2) dynamical simulations which use the low orbital eccentricity of Charon to constrain the mass of any third body near Pluto, and (3) analysis of Hubble Space Telescope (HST) archival images to search for satellites in the inner Pluto-Charon system. Although no objects were found, significant new constraints on bodies orbiting in the inner Pluto-Charon system were obtained.

Stern, S. Alan; Parker, Joel William; Duncan, Martin J.; Snowdall, J. Clark, Jr.; Levison, Harold F.

1994-01-01

17

Cross-calibration of Earth Observing System Terra satellite sensors MODIS and ASTER  

NASA Astrophysics Data System (ADS)

The Advanced Spaceborne Thermal Emissive and Reflection Radiometer (ASTER) and Moderate Resolution Imaging Spectrometer (MODIS) are two of the five sensors onboard the Earth Observing System's Terra satellite. These sensors share many similar spectral channels while having much different spatial and operational parameters. ASTER is a tasked sensor and sometimes referred to a zoom camera of the MODIS that collects a full-earth image every one to two days. It is important that these sensors have a consistent characterization and calibration for continued development and use of their data products. This work uses a variety of test sites to retrieve and validate intercalibration results. The refined calibration of Collection 6 of the Terra MODIS data set is leveraged to provide the up-to-date reference for trending and validation of ASTER. Special attention is given to spatially matching radiance measurements using prelaunch spatial response characterization of MODIS. Despite differences in spectral band properties and spatial scales, ASTER-MODIS is an ideal case for intercomparison since the sensors have nearly identical views and acquisitions times and therefore can be used as a baseline of intercalibration performance of other satellite sensor pairs.

McCorkel, J.

2014-09-01

18

A regional CO2 observing system simulation experiment for the ASCENDS satellite mission  

NASA Astrophysics Data System (ADS)

Top-down estimates of the spatiotemporal variations in emissions and uptake of CO2 will benefit from the increasing measurement density brought by recent and future additions to the suite of in situ and remote CO2 measurement platforms. In particular, the planned NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) satellite mission will provide greater coverage in cloudy regions, at high latitudes, and at night than passive satellite systems, as well as high precision and accuracy. In a novel approach to quantifying the ability of satellite column measurements to constrain CO2 fluxes, we use a portable library of footprints (surface influence functions) generated by the Stochastic Time-Inverted Lagrangian Transport (STILT) model in combination with the Weather Research and Forecasting (WRF) model in a regional Bayesian synthesis inversion. The regional Lagrangian particle dispersion model framework is well suited to make use of ASCENDS observations to constrain weekly fluxes in North America at a high resolution, in this case at 1° latitude × 1° longitude. We consider random measurement errors only, modeled as a function of the mission and instrument design specifications along with realistic atmospheric and surface conditions. We find that the ASCENDS observations could potentially reduce flux uncertainties substantially at biome and finer scales. At the grid scale and weekly resolution, the largest uncertainty reductions, on the order of 50%, occur where and when there is good coverage by observations with low measurement errors and the a priori uncertainties are large. Uncertainty reductions are smaller for a 1.57 ?m candidate wavelength than for a 2.05 ?m wavelength, and are smaller for the higher of the two measurement error levels that we consider (1.0 ppm vs. 0.5 ppm clear-sky error at Railroad Valley, Nevada). Uncertainty reductions at the annual biome scale range from ~40% to ~75% across our four instrument design cases and from ~65% to ~85% for the continent as a whole. Tests suggest that the quantitative results are moderately sensitive to assumptions regarding a priori uncertainties and boundary conditions. The a posteriori flux uncertainties we obtain, ranging from 0.01 to 0.06 Pg C yr-1 across the biomes, would meet requirements for improved understanding of long-term carbon sinks suggested by a previous study.

Wang, J. S.; Kawa, S. R.; Eluszkiewicz, J.; Baker, D. F.; Mountain, M.; Henderson, J.; Nehrkorn, T.; Zaccheo, T. S.

2014-12-01

19

A Regional CO2 Observing System Simulation Experiment for the ASCENDS Satellite Mission  

NASA Technical Reports Server (NTRS)

Top-down estimates of the spatiotemporal variations in emissions and uptake of CO2 will benefit from the increasing measurement density brought by recent and future additions to the suite of in situ and remote CO2 measurement platforms. In particular, the planned NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) satellite mission will provide greater coverage in cloudy regions, at high latitudes, and at night than passive satellite systems, as well as high precision and accuracy. In a novel approach to quantifying the ability of satellite column measurements to constrain CO2 fluxes, we use a portable library of footprints (surface influence functions) generated by the WRF-STILT Lagrangian transport model in a regional Bayesian synthesis inversion. The regional Lagrangian framework is well suited to make use of ASCENDS observations to constrain fluxes at high resolution, in this case at 1 degree latitude x 1 degree longitude and weekly for North America. We consider random measurement errors only, modeled as a function of mission and instrument design specifications along with realistic atmospheric and surface conditions. We find that the ASCENDS observations could potentially reduce flux uncertainties substantially at biome and finer scales. At the 1 degree x 1 degree, weekly scale, the largest uncertainty reductions, on the order of 50 percent, occur where and when there is good coverage by observations with low measurement errors and the a priori uncertainties are large. Uncertainty reductions are smaller for a 1.57 micron candidate wavelength than for a 2.05 micron wavelength, and are smaller for the higher of the two measurement error levels that we consider (1.0 ppm vs. 0.5 ppm clear-sky error at Railroad Valley, Nevada). Uncertainty reductions at the annual, biome scale range from 40 percent to 75 percent across our four instrument design cases, and from 65 percent to 85 percent for the continent as a whole. Our uncertainty reductions at various scales are substantially smaller than those from a global ASCENDS inversion on a coarser grid, demonstrating how quantitative results can depend on inversion methodology. The a posteriori flux uncertainties we obtain, ranging from 0.01 to 0.06 Pg C yr-1 across the biomes, would meet requirements for improved understanding of long-term carbon sinks suggested by a previous study.

Wang, J. S.; Kawa, S. R.; Eluszkiewicz, J.; Baker, D. F.; Mountain, M.; Henderson, J.; Nehrkorn, T.; Zaccheo, T. S.

2014-01-01

20

A regional CO2 observing system simulation experiment for the ASCENDS Satellite Mission  

NASA Astrophysics Data System (ADS)

Top-down estimates of the spatiotemporal variations in emissions and uptake of CO2 will benefit from the increasing measurement density brought by recent and future additions to the suite of in situ and remote CO2 measurement platforms. In particular, the planned NASA Active Sensing of CO2 Emissions over Nights, Days, and Seasons (ASCENDS) satellite mission will provide greater coverage in cloudy regions, at high latitudes, and at night than passive satellite systems, as well as high precision and accuracy. In a novel approach to quantifying the ability of satellite column measurements to constrain CO2 fluxes, we use a portable library of footprints (surface influence functions) generated by the WRF-STILT Lagrangian transport model in a regional Bayesian synthesis inversion. The regional Lagrangian framework is well suited to make use of ASCENDS observations to constrain fluxes at high resolution, in this case at 1° latitude × 1° longitude and weekly for North America. We consider random measurement errors only, modeled as a function of mission and instrument design specifications along with realistic atmospheric and surface conditions. We find that the ASCENDS observations could potentially reduce flux uncertainties substantially at biome and finer scales. At the 1° × 1°, weekly scale, the largest uncertainty reductions, on the order of 50%, occur where and when there is good coverage by observations with low measurement errors and the a priori uncertainties are large. Uncertainty reductions are smaller for a 1.57 ?m candidate wavelength than for a 2.05 ?m wavelength, and are smaller for the higher of the two measurement error levels that we consider (1.0 ppm vs. 0.5 ppm clear-sky error at Railroad Valley, Nevada). Uncertainty reductions at the annual, biome scale range from ∼40% to ∼75% across our four instrument design cases, and from ∼65% to ∼85% for the continent as a whole. Our uncertainty reductions at various scales are substantially smaller than those from a global ASCENDS inversion on a coarser grid, demonstrating how quantitative results can depend on inversion methodology. The a posteriori flux uncertainties we obtain, ranging from 0.01 to 0.06 Pg C yr-1 across the biomes, would meet requirements for improved understanding of long-term carbon sinks suggested by a previous study.

Wang, J. S.; Kawa, S. R.; Eluszkiewicz, J.; Baker, D. F.; Mountain, M.; Henderson, J.; Nehrkorn, T.; Zaccheo, T. S.

2014-05-01

21

Preliminary design of a satellite observation system for Space Station Freedom  

NASA Technical Reports Server (NTRS)

Degobah Satellite Systems (DSS), in cooperation with the University Space Research Association (USRA), NASA - Johnson Space Center (JSC), and the University of Texas, has completed the preliminary design of a satellite system to provide inexpensive on-demand video images of all or any portion of Space Station Freedom (SSF). DSS has narrowed the scope of the project to complement the work done by Mr. Dennis Wells at Johnson Space Center. This three month project has resulted in completion of the preliminary design of AERCAM, the Autonomous Extravehicular Robotic Camera, detailed in this design report. This report begins by providing information on the project background, describing the mission objectives, constraints, and assumptions. Preliminary designs for the primary concept and satellite subsystems are then discussed in detail. Included in the technical portion of the report are detailed descriptions of an advanced imaging system and docking and safing systems that ensure compatibility with the SSF. The report concludes by describing management procedures and project costs.

Cabe, Greg (editor); Gallagher, Chris; Wilson, Brian; Rehfeld, James; Maurer, Alexa; Stern, Dan; Nualart, Jaime; Le, Xuan-Trang

1992-01-01

22

Evolution of the Loop Current System During the Deepwater Horizon Oil Spill Event as Observed With Drifters and Satellites  

Microsoft Academic Search

The ocean circulation patterns of the Gulf of Mexico (GOM) Loop Current (LC) system and their effects on the advection of the oil discharged during the Deepwater Horizon incident are described using in situ surface drifter trajectories and satellite observations from May to August 2010. These observations include altimetry-derived surface geostrophic velocities, sea surface temperature, ocean color, and surface oil

Yonggang Liu; Robert H. Weisberg; Chuanmin Hu; Charles Kovach

2011-01-01

23

A System for Simulating CLARREO Footprints From Satellite Observations and Models  

Microsoft Academic Search

A data access system has been developed to provide scientists with the tools needed for assessing design decisions with regards to the CLARREO mission. This system employs a cluster of distributed database servers to provide rapid queries of global data sets spanning multiple years. The distributed databases is populated with simulated CLARREO footprints from existing satellite high spectral resolution infrared

S. Dutcher; F. Best; R. Garcia; R. Holz; R. Knuteson; H. Revercomb; J. Taylor; D. Tobin; H. Woolf

2008-01-01

24

The Earth Observing System Microwave Limb Sounder (EOS MLS) on the Aura Satellite  

NASA Technical Reports Server (NTRS)

The Earth Observing System Microwave Limb Sounder measures several atmospheric chemical species (OH, HO2, H2O, O3, HCl, ClO, HOCl, BrO, HNO3, N2O, CO, HCN, CH3CN, volcanic SO2), cloud ice, temperature, and geopotential height to improve our understanding of stratospheric ozone chemistry, the interaction of composition and climate, and pollution in the upper troposphere. All measurements are made simultaneously and continuously, during both day and night. The instrument uses heterodyne radiometers that observe thermal emission from the atmospheric limb in broad spectral regions centered near 118, 190, 240, and 640 GHz, and 2.5 THz. It was launched July 15, 2004 on the National Aeronautics and Space Administration's Aura satellite and started full-up science operations on August 13, 2004. An atmospheric limb scan and radiometric calibration for all bands are performed routinely every 25 s. Vertical profiles are retrieved every 165 km along the suborbital track, covering 82 S to 82 N latitudes on each orbit. Instrument performance to date has been excellent; data have been made publicly available; and initial science results have been obtained.

Waters, Joe W.; Froidevaux, Lucien; Harwood, Robert S.; Jarnot, Robert F.; Pickett, Herbert M.; Read, William G.; Siegel, Peter H.; Cofield, Richard E.; Filipiak, Mark J.; Flower, Dennis A.; Holden, James R.; Lau, Gary K.; Livesey, Nathaniel J.; Manney, Gloria L; Pumphrey, Hugh C.; Santee, Michelle L.; Wu, Dong L.; Cuddy, David T.; Lay, Richard R.; Loo, Mario S.; Perun, Vincent S.; Schwartz, Michael J.; Stek, Paul C.; Thurstans, Robert P.; Boyles, Mark A.

2006-01-01

25

NASA's Satellite Observations for Atmospheric Composition Studies  

Microsoft Academic Search

Satellite studies of the Earth system constitute the primary emphasis of NASA's Earth Science Enterprise (ESE). Atmospheric composition is one of the six interdisciplinary focus areas around which NASA's ESE implements its research program, and together with its domestic and international partners, NASA is making significant steps to improve our knowledge of global atmospheric composition through use of satellite observations.

J. Kaye; P. Decola

2004-01-01

26

Astrometry of natural satellites: improving the dynamics of planetary systems with old observations.  

NASA Astrophysics Data System (ADS)

A new astrometric reduction of old photographic plates, benefiting from modern technologies such as sub-micrometric scanners associated with a reduction using accurate catalogues (UCAC at the present time and GAIA in a near future), provides improved knowledge of the orbital motion of planetary satellites.In the framework of an international collaboration first, and in the FP7 ESPaCE european project afterward, U.S. Naval Observatory plates were digitized with the new generation DAMIAN scanning machine of the Royal Observatory of Belgium. The procedure was applied to a few hundred photographic plates of the Galilean satellites covering the years 1967-1998, and of the Martian satellites covering the years 1967-1997. We provide results with an accuracy better than 70 mas in (RA,Dec) positions of the Galilean moons, and better than 60 mas in (RA,Dec) positions of the Martian satellites.Since the positions of Jupiter and Mars may be deduced from the observed (RA,Dec) positions of their satellites, we can also assess the accuracy of the ephemerides of Jupiter and Mars.

Robert, Vincent; Pascu, Dan; Lainey, Valery; Arlot, Jean-Eudes

2014-05-01

27

The dynamics of Martian satellites from observations  

NASA Astrophysics Data System (ADS)

This paper deals with the study of the motion of Martian satellites and with the determination of kinematic and dynamic parameters describing this system of satellites and planet. The values of these parameters are found on the basis of all available data of ground-based and space-based observations of Phobos and Deimos. The original analytical theory of the motion of the satellites was used and the data set was wider than in similar papers of other authors. Thus, a new specified model of the motion of Mars' satellites has been constructed.

Emelyanov, N. V.; Vashkovyak, S. N.; Nasonova, L. P.

1993-01-01

28

Operational Applications of Satellite Snowcover Observations  

NASA Technical Reports Server (NTRS)

The history of remote sensing of snow cover is reviewed and the following topics are covered: various techniques for interpreting LANDSAT and NOAA satellite data; the status of future systems for continuing snow hydrology applications; the use of snow cover observations in streamflow forecasts by Applications Systems Verification and Transfer participants and selected foreign investigators; and the benefits of using satellite snow cover data in runoff prediction.

Rango, A. (editor); Peterson, R. (editor)

1980-01-01

29

Applications of Satellite Total Lightning Observations  

NASA Technical Reports Server (NTRS)

Low-earth orbit satellite measurements of total lightning have diverse applications for lightning-related NOx production. Topics to be covered include: (1) current availability of gridded global and tropical lightning climatologies from the OTD and LIS sensors; (2) estimation of the IC:CG ratio from combination of satellite and surface network observations (relevant for net storm production); (3) determination of land and ocean storm flash rate spectra, and their implications for parameterized "scaling law" approaches to lightning NOx estimation; and (4) use of satellite observations to assess and correct for the range-dependent performance of groundbased systems, including LDAR and NLDN.

Boccippio, Dennis J.; Christian, High J.; Arnold, James E. (Technical Monitor)

2001-01-01

30

Ocean observer study: A proposed national asset to augment the future U.S. operational satellite system  

USGS Publications Warehouse

The next generation of U.S. polar orbiting environmental satellites, are now under development. These satellites, jointly developed by the Department of Defense (DoD), the Department of Commerce (DOC), and the National Aeronautics and Space Administration (NASA), will be known as the National Polar-orbiting Operational Environmental Satellite System (NPOESS). It is expected that the first of these satellites will be launched in 2010. NPOESS has been designed to meet the operational needs of the U.S. civilian meteorological, environmental, climatic, and space environmental remote sensing programs, and the Global Military Space and Geophysical Environmental remote sewing programs. This system, however, did not meet all the needs of the user community interested in operational oceanography (particularly in coastal regions). Beginning in the fall of 2000, the Integrated Program Office (IPO), a joint DoD, DOC, and NASA office responsible for the NPOESS development, initiated the Ocean Observer Study (OOS). The purpose of this study was to assess and recommend how best to measure the missing or inadequately sampled ocean parameters. This paper summarizes the ocean measurement requirements documented in the OOS, describes the national need to measure these parameters, and describes the satellite instrumentation required to make those measurements.

Cunningham, J.D.; Chambers, D.; Davis, C.O.; Gerber, A.; Helz, R.; McGuire, J.P.; Pichel, W.

2003-01-01

31

Satellite Observations of Tropospheric Chemistry  

NASA Technical Reports Server (NTRS)

The troposphere is an essential component of the earth's life support system as well as the gateway for the exchange of chemicals between different geochemical reservoirs of the earth. The chemistry of the troposphere is sensitive to perturbation from a wide range of natural phenomena and human activities. The societal concern has been greatly enhanced in recent decades due to ever increasing pressures of population growth and industrialization. Chemical changes within the troposphere control a vast array of processes that impact human health, the biosphere, and climate. A main goal of tropospheric chemistry research is to measure and understand the response of atmospheric composition to natural and anthropogenic perturbations, and to develop the capability to predict future change. Atmospheric chemistry measurements are extremely challenging due to the low concentrations of critical species and the vast scales over which the observations must be made. Available tropospheric data are mainly from surface sites and aircraft missions. Because of the limited temporal extent of aircraft observations, we have very limited information on tropospheric composition above the surface. This situation can be contrasted to the stratosphere, where satellites have provided critical and detailed chemical data on the global distribution of key trace gases.

Singh, Hanwant B.; Jacob, Daniel J.; Hipskind, R. Stephen (Technical Monitor)

2001-01-01

32

Geopotential Error Analysis from Satellite Gradiometer and Global Positioning System Observables on Parallel Architecture  

NASA Technical Reports Server (NTRS)

The recovery of a high resolution geopotential from satellite gradiometer observations motivates the examination of high performance computational techniques. The primary subject matter addresses specifically the use of satellite gradiometer and GPS observations to form and invert the normal matrix associated with a large degree and order geopotential solution. Memory resident and out-of-core parallel linear algebra techniques along with data parallel batch algorithms form the foundation of the least squares application structure. A secondary topic includes the adoption of object oriented programming techniques to enhance modularity and reusability of code. Applications implementing the parallel and object oriented methods successfully calculate the degree variance for a degree and order 110 geopotential solution on 32 processors of the Cray T3E. The memory resident gradiometer application exhibits an overall application performance of 5.4 Gflops, and the out-of-core linear solver exhibits an overall performance of 2.4 Gflops. The combination solution derived from a sun synchronous gradiometer orbit produce average geoid height variances of 17 millimeters.

Schutz, Bob E.; Baker, Gregory A.

1997-01-01

33

A comparison of mapped and measured total ionospheric electron content using global positioning system and beacon satellite observations  

Microsoft Academic Search

Total ionospheric electron contents (TEC) were measured by global positioning system (GPS) dual-frequency receivers developed by the Jet Propulsion Laboratory. The measurements included P-code (precise ranging code) and carrier phase data for six GPS satellites during multiple five-hour observing sessions. A set of these GPS TEC measurements were mapped from the GPS lines of sight to the line of sight

Gabor E. Lanyi; Titus Roth

1988-01-01

34

Future Satellite Observations of Solar Irradiance  

NASA Technical Reports Server (NTRS)

Required solar irradiance measurements for climate studies include those now being made by the Total Irradiance Monitor (TIM) and the Spectral Irradiance Monitor (SIM) onboard the SORCE satellite, part of the Earth Observing System fleet of NASA satellites. Equivalent or better measures of Total Solar Irradiance (TSI) and Spectral Solar Irradiance (SSI, 200 to 2000 nm) are planned for the post-2010 satellites of the National Polar-orbiting Operational Environmental Satellite System ("OESS). The design life of SORCE is 5 years, so a "Solar Irradiance Gap Filler" EOS mission is being planned for launch in the 2007 time frame, to include the same TSI and SSI measurements. Besides avoiding any gap, overlap of the data sources is also necessary for determination of possible multi-decadal trends in solar irradiance. We discuss these requirements and the impacts of data gaps, and data overlaps, that may occur in the monitoring of the critical solar radiative forcing.

Cahalan, R. F.; Rottman, G.; Woods, T.; Lawrence, G.; Harder, J.; McClintock, W.; Kopp, G.

2003-01-01

35

Full time and full coverage global observation system for ecological monitoring base on MEO satellite grid constellation  

NASA Astrophysics Data System (ADS)

Human life more and more rely on earth environment and atmosphere, environmental information required by space based monitor is a crucial importance, although GEO and polar weather satellite in orbit by several countries, but it can’t monitor all zone of earth with real time. This paper present a conception proposal which can realize stable, continue and real time observation for any zone(include arctic and ant-arctic zone) of earth and its atmosphere, it base on walker constellation in 20000Km high medium orbit with 24 satellites, payloads configuration with infrared spectrometer, visible camera, ultraviolet ray camera, millimeter wave radiometer, leaser radar, spatial resolution are 1km@ infrared,0.5km@ visible optical. This satellite of grid constellation can monitor any zone of global with 1-3hours retrial observation cycles. Air pollution, ozone of atmosphere, earth surface pollution, desert storm, water pollution, vegetation change, natural disasters, man-made emergency situations, agriculture and climate change can monitor by this MEO satellite grid constellation. This system is a international space infrastructure, use of mature technologies and products, can build by co-operation with multi countries.

You, Rui; Liu, Shuhao

36

Satellite system survivability  

SciTech Connect

Present U.S. military capability relies heavily on Earth satellites to maintain connectivity. The essential nature of these satellite systems has made them tempting targets to nuclear attack in wartime. The author reviews U.S. history in high-altitude nuclear device testing and nuclear effects testing on satellites, events in which he directly participated. Physics of the production of nuclear enhanced high-altitude electron belts are reviewed. The author discusses primary effects of the enhanced environment on satellite components. A glimpse into future satellite hardening reveals measures against developing directed energy weapons.

Shelton, F.H.

1983-01-01

37

Satellite Antenna Systems  

NASA Technical Reports Server (NTRS)

Through the Technology Affiliates Program at the Jet Propulsion Laboratory, the ACTS antenna system was transferred from experimental testing status to commercial development with KVH Industries, Inc. The ACTS design enables mobile satellite antennas to remain pointed at the satellite, regardless of the motion or vibration on which it is mounted. KVH's first product based on the ACTS design is a land-mobile satellite antenna system that will enable direct broadcast satellite television aboard moving trucks, recreational vehicles, trains, and buses. Future products could include use in broadcasting, emergency medical and military vehicles.

1997-01-01

38

Heuristics for scheduling Earth observing satellites  

Microsoft Academic Search

This paper describes several methods for assigning tasks to Earth Observing Systems Satellites (EOS). We present empirical results for three heuristics, called: Priority Dispatch (PD), Look Ahead (LA), and Genetic Algorithm (GA). These heuristics progress from simple to complex, from less accurate to more accurate, and from fast to slow. We present empirical results as applied to the Window-Constrained Packing

William J. Wolfe; Stephen E. Sorensen

1999-01-01

39

Advanced communications satellite systems  

NASA Technical Reports Server (NTRS)

There is a rapidly growing demand for satellite circuits, particularly for domestic service within the U.S. NASA's current program is aimed at developing the high risk, advanced satellite communications technologies required to significantly increase the capacity of future satellite communications systems. Attention is given to aspects of traffic distribution and service scenario, problems related to effects of rain attenuation, details regarding system configuration, a 30/20 GHz technology development approach, an experimental flight system, the communications payload for the experimental flight system, a typical experiment flight system coverage, and a typical three axis stabilized flight spacecraft.

Sivo, J. N.

1983-01-01

40

Voyager 2 radio science observations of the uranian system: atmosphere, rings, and satellites.  

PubMed

Voyager 2 radio occultation measurements of the Uranian atmosphere were obtained between 2 and 7 degrees south latitude. Initial atmospheric temperature profiles extend from pressures of 10 to 900 millibars over a height range of about 100 kilometers. Comparison of radio and infrared results yields mole fractions near the tropopause of 0.85 and 0.15 +/- 0.05 for molecular hydrogen and helium, respectively, if no other components are present; for this composition the tropopause is at about 52 kelvins and 110 millibars. Distinctive features in the signal intensity measurements for pressures above 900 millibars strongly favor model atmospheres that include a cloud deck of methane ice. Modeling of the intensity measurements for the cloud region and below indicates that the cloud base is near 1,300 millibars and 81 kelvins and yields an initial methane mole fraction of about 0.02 for the deep atmosphere. Scintillations in signal intensity indicate small-scale stucture throughout the stratosphere and upper troposphere. As judged from data obtained during occultation ingress, the ionosphere consists of a multilayer structure that includes two distinct layers at 2,000 and 3,500 kilometers above the 100-millibar level and an extended topside that may reach altitudes of 10,000 kilometers or more. Occultation measurements of the nine previously known rings at wavelengths of 3.6 and 13 centimeters show characteristic values of optical depth between about 0.8 and 8; the maxim value occurs in the outer region of the in ring, near its periapsis. Forward-scattered signals from this ring have properties that differ from those of any of Saturn's rings, and they are inconsistent with a discrete scattering object or local (three-dimensional) assemblies of orbiting objects. These signals suggest a new kdnd of planetary ring feature characterized by highly ordered cylindrical substructures of radial scale on the order of meters and azimuthal scale of kilometers or more. From radio data alone the mass of the Uranian system is GM(sys) = 5,794,547- 60 cubic kilometers per square second; from a combination of radio and optical navigation data the mass of Uranus alone is GM(u) = 5,793,939+/- 60 cubic kilometers per square second. From all available Voyager data, induding imaging radii, the mean uncompressed density of the five major satellites is 1.40+/- 0.07 grams per cubic centimeter; this value is consistent with a solar mix of material and apparently rules out a cometary origin of the satellites. PMID:17812893

Tyler, G L; Sweetnam, D N; Anderson, J D; Campbell, J K; Eshleman, V R; Hinson, D P; Levy, G S; Lindal, G F; Marouf, E A; Simpson, R A

1986-07-01

41

SST subseasonal variability in the central Benguela upwelling system as inferred from satellite observations (19992009)  

E-print Network

) decomposition and wavelet analysis. Despite the land contamination of the TMI satellite data within.g., Shannon et al., 1986; Floren- chie et al., 2003, 2004; Rouault et al., 2007; Lubbecke et al., 2010

Boyer, Edmond

42

Civil satellite navigation systems  

NASA Astrophysics Data System (ADS)

The use of satellite navigation for civil purposes is examined critically to compare the merits and costs of existing and practical satellite systems. Accuracy and range considerations are reviewed, and the basic requirements of radionavigation systems are set forth. Specific data are given regarding coverage area, integration with ground-based systems, monitoring and control, and accuracy. Systems reviewed include 'Starfix,' Inmarsat, EVA Vavsat, and Geostar/Locstar/Omnitracs, and extensive illustrations are provided to demonstrate constellation geometries. When in view, two or three geosynchronous satellites can provide acceptable fixing, and 9 satellites can provide global coverage. It is argued that systems such as 'Starfix' are commercially viable with less than 100 users, and Inmarsat is identified as an effective European civil system.

Blanchard, Walter F.

1991-07-01

43

Applications systems verification and transfer project. Volume 1: Operational applications of satellite snow cover observations: Executive summary. [usefulness of satellite snow-cover data for water yield prediction  

NASA Technical Reports Server (NTRS)

Both LANDSAT and NOAA satellite data were used in improving snowmelt runoff forecasts. When the satellite snow cover data were tested in both empirical seasonal runoff estimation and short term modeling approaches, a definite potential for reducing forecast error was evident. A cost benefit analysis run in conjunction with the snow mapping indicated a $36.5 million annual benefit accruing from a one percent improvement in forecast accuracy using the snow cover data for the western United States. The annual cost of employing the system would be $505,000. The snow mapping has proven that satellite snow cover data can be used to reduce snowmelt runoff forecast error in a cost effective manner once all operational satellite data are available within 72 hours after acquisition. Executive summaries of the individual snow mapping projects are presented.

Rango, A.

1981-01-01

44

First observations of the Solar-system objects with the ISO satellite  

Microsoft Academic Search

The Infrared Space Observatory (ISO) satellite was launched by the European Space Agency in November 1995. It consists of a helium-cooled 60-cm telescope and four focal plane instruments (one camera, one photometer and two spectrometers) covering altogether the 2.5-200 micron range. Their spectroscopic cababilities have resolving powers ranging from 50 (CVF mode of the camera) to 15000-20000 (Fabry-Perot modes of

Th. Encrenaz

1997-01-01

45

Jupiter System Observer  

NASA Technical Reports Server (NTRS)

This slide presentation reviews the proposed mission for the Jupiter System Observer. The presentation also includes overviews of the mission timeline, science goals, and spacecraftspecifications for the satellite.

Senske, Dave; Kwok, Johnny

2008-01-01

46

Transit satellite system timing capabilities  

NASA Technical Reports Server (NTRS)

Current time transfer capabilities of the Transit Satellite System are reviewed. Potential improvements in the changes in equipment and operational procedures using operational satellites are discussed.

Finsod, T. D.

1978-01-01

47

Linking Regional Satellite Observations with Coupled Human-Ecological Systems in Global Drylands  

NASA Astrophysics Data System (ADS)

The African Sahel has attracted consistent attention since a series of droughts in the 1970s and 1980s caused widespread famine and land degradation (desertification). These events spawned international conventions and sustained development efforts to increase food security and reverse poverty for the local populations, and to arrest environmental degradation. Since 1985, several studies using satellite data have described a general “greening” in response to increased rainfall trends. However, some areas show more greening while others less greening than can be explained by precipitation alone (Glob. Env. Change 15- 2005). The debated question is how to explain the residual changes: management, policy, human adaptation, or something else? Placing results in an human-ecological framework could help answer this question. Providing a meaningful assessment will allow national and international agencies to evaluate the effectiveness of alternative approaches to poverty alleviation and environmental restoration in drylands at regional and global scales.

Hutchinson, C.; Reynolds, J. F.

2009-12-01

48

Measurements of tropospheric NO2 in Romania using a zenith-sky mobile DOAS system and comparisons with satellite observations.  

PubMed

In this paper we present a new method for retrieving tropospheric NO2 Vertical Column Density (VCD) from zenith-sky Differential Optical Absorption Spectroscopy (DOAS) measurements using mobile observations. This method was used during three days in the summer of 2011 in Romania, being to our knowledge the first mobile DOAS measurements peformed in this country. The measurements were carried out over large and different areas using a mobile DOAS system installed in a car. We present here a step-by-step retrieval of tropospheric VCD using complementary observations from ground and space which take into account the stratospheric contribution, which is a step forward compared to other similar studies. The detailed error budget indicates that the typical uncertainty on the retrieved NO2tropospheric VCD is less than 25%. The resulting ground-based data set is compared to satellite measurements from the Ozone Monitoring Instrument (OMI) and the Global Ozone Monitoring Experiment-2 (GOME-2). For instance, on 18 July 2011, in an industrial area located at 47.03°N, 22.45°E, GOME-2 observes a tropospheric VCD value of (3.4 ± 1.9) × 1015 molec./cm2, while average mobile measurements in the same area give a value of (3.4 ± 0.7) × 10(15) molec./cm2. On 22 August 2011, around Ploiesti city (44.99°N, 26.1°E), the tropospheric VCD observed by satellites is (3.3 ± 1.9) × 10(15) molec./cm2 (GOME-2) and (3.2 ± 3.2) × 10(15) molec./cm2 (OMI), while average mobile measurements give (3.8 ± 0.8) × 10(15) molec./cm2. Average ground measurements over "clean areas", on 18 July 2011, give (2.5 ± 0.6) × 10(15) molec./cm2 while the satellite observes a value of (1.8 ± 1.3) × 10(15) molec./cm2. PMID:23519349

Constantin, Daniel-Eduard; Merlaud, Alexis; Van Roozendael, Michel; Voiculescu, Mirela; Fayt, Caroline; Hendrick, François; Pinardi, Gaia; Georgescu, Lucian

2013-01-01

49

Satellite Observations for Detecting and Tracking Changes in Atmospheric Composition  

EPA Science Inventory

The international scientific community's Integrated Global Atmosphere Chemistry Observation System report outlined a plan for ground-based, airborne and satellite Measurements, and models to integrate the observations into a 4-dimensional representation of the atmosphere (space a...

50

Severe storms observing satellite (STORMSAT)  

NASA Technical Reports Server (NTRS)

The primary payload for this satellite is the Advanced Atmospheric Sounding and Imaging Radiometer which will perform precise infrared temperature sounding and visible/infrared imaging from geostationary orbit. A secondary payload instrument which may be utilized on STORMSAT is the Microwave Atmospheric Sounding Radiometer which provides an independent set of temperature and humidity sounding in cloudy, meteorologically active regions. The study provides satellite designs and identifies mission-unique subsystems using the Multimission Modular Spacecraft using a Shuttle/Interim Upper Stage launch vehicle.

1976-01-01

51

Orbit Design of Earth-Observation Satellite  

NASA Astrophysics Data System (ADS)

The purpose of this study is to design a reliable orbit for a medium-resolution scientific satellite to observe Earth for developmental issues such as water resources, agricultural, and industrial. To meet this objective this study firstly, defines the mission, secondly, determines mission constraints, thirdly, design the attitude and orbit control system. As for the observation requirements, and the revisit time are provided as a function of the orbital parameters. Initial orbital parameters are obtained by optimal analysis between observation characteristics and attitude and orbit maintenance costs. Long term station-keeping strategies will be provided for the proposed solutions. Impulsive control will be investigated to provide a reliable and affordable attitude and orbit control system.

Owis, Ashraf

52

Monitoring Changes in Water Resources Systems Using High Resolution Satellite Observations: Application to Lake Urmia  

NASA Astrophysics Data System (ADS)

Lake Urmia with its unique ecosystem in northwestern Iran is the second largest saltwater lake in the world. It is home of more than 300 species of birds, reptiles, and mammals with high salinity level of more than 300 g/l. In recent years, a significant water retreat has occurred in this lake. In this study, we tried to monitor the desiccation of the lake over more than four decades using remote sensing observations. Multi-spectral high-resolution LandSat images of the Lake Urmia region from 1972 to 2012 were acquired to derive the lake area. The composite maps of the lake were created, and a Bayesian Maximum Likelihood classification technique was used to classify land and water in the composite maps. The time series of the lake area reveals that it has shrunk by more than 40% in the past ten years. Moreover, water budget related components such as precipitation, soil moisture, and drought indices from remote sensing of the lake basin were utilized to investigate if droughts or climate change are the primary driving forces behind this phenomenon. These analyses show that the retreat of the lake is not related to droughts or global climate change as it has survived several drought events before year 2000. Similar analyses conducted on Lake Van located about 400 km west of Lake Urmia with very similar climate pattern revealed no significant areal change despite the lake's exposure to similar drought events. These results raise serious concern about the destructive role of unbridled development coupled with supply-oriented water management scheme driven by a classic upstream-downstream competition for water in the Lake Urmia region. There is an urgent need to investigate sustainable restoration initiatives for Lake Urmia in order to prevent an environmental disaster comparable to catastrophic death of Aral Sea.

Norouzi, H.; AghaKouchak, A.; Madani, K.; Mirchi, A.; Farahmand, A.; Conway, C.

2013-12-01

53

Satellite Navigation Systems  

NSDL National Science Digital Library

The Global Positioning System (GPS) has been in operation for several years, and its use is continually rising. GPS is the main satellite navigation system developed by the United States. There are countless applications of this technology, and numerous international efforts are currently underway.The Topcon Positioning Systems company provides an excellent introduction to GPS technology in its online book (1). The first couple chapters describe the evolution of GPS and its fundamentals, and the remaining material focuses on some specific issues. A more advanced tutorial is given through the IBM Web site (2). A brief, free registration is required to view it, and some familiarity with Java is recommended. The European Space Agency provides this page about satellite navigation (3), which describes, among other things, Galileo. This is not the astronomer; Galileo is Europe's version of GPS, scheduled for completion in 2008. Another system, developed by Russia, is detailed on the Space and Technology Web site (4). The short summary describes the 20-year history of the Global Navigation Satellite System (GLONASS), as well as upgrades that are in progress. Differential GPS, a service that is more accurate than standard GPS in areas with poor coverage, is operated by the US Coast Guard Navigation Center (5). Some information about the status of nationwide DGPS expansion is given. Several research and development projects, technology highlights, and GPS implementations are covered on the UNAVCO home page (6). The facility primarily fosters work to expand the applications of satellite navigation. With the wave of kidnapping cases reported across the country, a novel use of GPS is being marketed to keep track of children (7). These portable devices can be worn on the wrist, like a watch, so parents can always know where their kids are. Another news story describes the use of GPS in mining operations (8). The technology allows operators of huge three-story dump trucks to detect obstacles and maneuver the vehicle with only limited visibility.

Leske, Cavin.

2002-01-01

54

Applications systems verification and transfer project. Volume 5: Operational applications of satellite snow-cover observations, northwest United States  

NASA Technical Reports Server (NTRS)

The study objective was to develop or modify methods in an operational framework that would allow incorporation of satellite derived snow cover observations for prediction of snowmelt derived runoff. Data were reviewed and verified for five basins in the Pacific Northwest. The data were analyzed for up to a 6-year period ending July 1978, and in all cases cover a low, average, and high snow cover/runoff year. Cloud cover is a major problem in these springtime runoff analyses and have hampered data collection for periods of up to 52 days. Tree cover and terrain are sufficiently dense and rugged to have caused problems. The interpretation of snowlines from satellite data was compared with conventional ground truth data and tested in operational streamflow forecasting models. When the satellite snow-covered area (SCA) data are incorporated in the SSARR (Streamflow Synthesis and Reservoir Regulation) model, there is a definite but minor improvement.

Dillard, J. P.

1981-01-01

55

Satellite Observations towards the Agriculture applications  

E-print Network

Satellite Observations towards the Agriculture applications Osamu Ochiai Japan Aerospace Weather (temperature, etc.) #12;Soil Moisture Drought monitoring in North-East Argentina by Aqua with other satellite data Land vegetation, ocean chlorophyll-a, and primary production Sea and Land surface

56

Satellite freeze forecast system  

NASA Technical Reports Server (NTRS)

Provisions for back-up operations for the satellite freeze forecast system are discussed including software and hardware maintenance and DS/1000-1V linkage; troubleshooting; and digitized radar usage. The documentation developed; dissemination of data products via television and the IFAS computer network; data base management; predictive models; the installation of and progress towards the operational status of key stations; and digital data acquisition are also considered. The d addition of dew point temperature into the P-model is outlined.

Martsolf, J. D. (principal investigator)

1983-01-01

57

Techniques for computing regional radiant emittances of the earth-atmosphere system from observations by wide-angle satellite radiometers, phase 3  

NASA Technical Reports Server (NTRS)

Radiometers on earth orbiting satellites measure the exchange of radiant energy between the earth-atmosphere (E-A) system and space at observation points in space external to the E-A system. Observations by wideangle, spherical and flat radiometers are analyzed and interpreted with regard to the general problem of the earth energy budget (EEB) and to the problem of determining the energy budget of regions smaller than the field of view (FOV) of these radiometers.

Pina, J. F.; House, F. B.

1975-01-01

58

Magnetopause structure from satellite observations  

NASA Technical Reports Server (NTRS)

Observations on magnetopause structure are reported. Major topics covered include: classical reconnection, transport mechanisms, magnetospheric boundary layers, tearing modes, and Jupiter's magnetopause.

Sonnerup, B. U. O.

1979-01-01

59

Investigation of mesoscale meteorological phenomena as observed by geostationary satellite  

NASA Technical Reports Server (NTRS)

Satellite imagery plus conventional synoptic observations were used to examine three mesoscale systems recently observed by the GOES-EAST satellite. The three systems are an arc cloud complex (ACC), mountain lee wave clouds and cloud streets parallel to the wind shear. Possible gravity-wave activity is apparent in all three cases. Of particular interest is the ACC because of its ability to interact with other mesoscale phenomena to produce or enhance convection.

Brundidge, K. C.

1982-01-01

60

Severe storms observing satellite study  

NASA Technical Reports Server (NTRS)

Payload distribution and the attitude control system for the multi-mission modular spacecraft/StormSat configuration are discussed. The design of the advanced atmospheric sounder and imaging radiometer (AASIR) gimbal drive and its servomechanism is described. Onboard data handling, data downlink communications, and ground data handling systems are developed. Additional topics covered include: magnetic unloading at synchronous altitude, north-south stationkeeping, and the feasibility and impact of flying the microwave atmospheric sounding radiometer (MASR) as an additional payload.

Iwens, R. P.; Stern, D. A.

1976-01-01

61

Lightning-Generated Whistler Waves Observed by Probes On The Communication/Navigation Outage Forecast System Satellite at Low Latitudes  

NASA Technical Reports Server (NTRS)

Direct evidence is presented for a causal relationship between lightning and strong electric field transients inside equatorial ionospheric density depletions. In fact, these whistler mode plasma waves may be the dominant electric field signal within such depletions. Optical lightning data from the Communication/Navigation Outage Forecast System (C/NOFS) satellite and global lightning location information from the World Wide Lightning Location Network are presented as independent verification that these electric field transients are caused by lightning. The electric field instrument on C/NOFS routinely measures lightning ]related electric field wave packets or sferics, associated with simultaneous measurements of optical flashes at all altitudes encountered by the satellite (401.867 km). Lightning ]generated whistler waves have abundant access to the topside ionosphere, even close to the magnetic equator.

Holzworth, R. H.; McCarthy, M. P.; Pfaff, R. F.; Jacobson, A. R.; Willcockson, W. L.; Rowland, D. E.

2011-01-01

62

Surface albedo based on geostationary satellite observations  

NASA Astrophysics Data System (ADS)

Surface albedo is the fraction of incoming solar radiation reflected by the land surface, and therefore is a sensitive indicator of environmental changes. To this end, surface albedo is identified as an Essential Climate Variable (ECV) by the Global Climate Observing System (GCOS). NOAA's National Climatic Data Center (NCDC) is implementing the Geostationary Surface Albedo (GSA; Lattanzio and Govaerts, 2010) algorithm for GOES data in support of an activity of the Sustained, Coordinated Processing of Environmental Satellite Data for Climate Monitoring (SCOPE-CM). SCOPE-CM helps coordinate ECV production responding to GCOS, WMO, and CEOS goals. The GSA algorithm was developed jointly by EUMETSAT and Joint Research Centre (JRC) using a method proposed by Pinty et al. (2000) to retrieve surface albedo by processing day-time, cloud-free geostationary observations from a single visible band. Currently, the GSA algorithm generates products operationally at EUMETSAT using geostationary data from satellites at 0° and 63°E and at JMA using 140°E geostationary data. To support development of an aggregate global albedo product, NCDC will apply the GSA algorithm to data from GOES-E (75°W) and GOES-W (135°W). For the GOES implementation, raw GOES observations are calibrated against AVHRR reflectance data available in PATMOS-x. Surface angular anisotropy is then determined through the inversion of the GSA radiative transfer model using multiple geostationary images collected over a day under different illumination conditions. The inversion process additionally requires ancillary total column ozone and water vapor values, which for the GOES implementation are acquired from the 20th Century Reanalysis V2 data set provided by the NOAA/OAR/ESRL PSD. The GSA algorithm produces a 10-day composite surface albedo map. This product will initially be developed for the period 2000-2003. Later, it will be applied to the complete GOES data collection (1978-present) as part of NOAA's Climate Data Record Program.

Matthews, J. L.; Lattanzio, A.; Hankins, B.; Inamdar, A.; Knapp, K.; Privette, J. L.

2011-12-01

63

Satellite observations of sea ice  

NASA Technical Reports Server (NTRS)

An overview is presented of Antarctic and Arctic sea ice studies using data from the Nimbus-5 ESMR and the Nimbus-7 SMMR passive microwave radiometers. Four years (1973-1976) of ESMR data for the Antarctic Ocean define the characteristics of the seasonal cycle including regional contrasts and interannual variations. Major advances include the discovery of the Weddell polynya and the presence of substantial areas of open water in the Antarctic winter pack ice. Regional differences in sea ice extent on time-scales of about a month are shown to be associated with variations in surface-wind fields. In the Arctic, the computation of sea ice concentration is complicated by the presence of multiyear ice, but the amount of multiyear ice becomes an important measurable quantity with dual-polarized, multifrequency passive microwave sensors. Analysis of SMMR data demonstrates its advantage for studying the spatial and temporal variability of the Arctic ice cover. Large observed interannual variations in the distribution of the multiyear pack ice and the presence of significant divergent areas in the central Arctic during winter contrast markedly with the classical view of the Arctic pack ice.

Cavalieri, D. J.; Zwally, H. J.

1985-01-01

64

Arctic Warming Signals from Satellite Observations  

NASA Technical Reports Server (NTRS)

Global warming signals are expected to be amplified in the Arctic primarily because of ice-albedo feedback associated with the high reflectivity of ice and snow that blankets much of the region. The Arctic had been a poorly explored territory basically because of its general inaccessibility on account of extremely harsh weather conditions and the dominant presence of thick perennial ice in the region. The advent of satellite remote sensing systems since the 1960s, however, enabled the acquisition of synoptic data that depict in good spatial detail the temporal changes of many Arctic surface parameters. Among the surface parameters that have been studied using space based systems are surface temperature, sea ice concentration, snow cover, surface albedo and phytoplankton concentration. Associated atmospheric parameters, such as cloud cover, temperature profile, ozone concentration, and aerosol have also been derived. Recent observational and phenomenological studies have indeed revealed progressively changing conditions in the Arctic during the last few decades (e g , Walsh et al. 1996; Serreze et al 2000; Comiso and Parkinson 2004). The changes included declines in the extent and area of surfaces covered by sea ice and snow, increases in melt area over the Greenland ice sheets, thawing of the permafrost, warming in the troposphere, and retreat of the glaciers. These observations are consistent with the observed global warming that has been associated with the increasing concentration of greenhouse gases in the atmosphere (Karl and Trenberth 2003) and confirmed by modeling studies (Holland and Bitz, 2003). The Arctic system, however, is still not well understood complicated by a largely fluctuating wind circulation and atmospheric conditions (Proshutinsky and Johnson 1997) and controlled by what is now known as the Arctic Oscillation (AO) which provides a measure of the strength of atmospheric activities in the region (Thompson and Wallace 1998). Meanwhile, the observed Arctic conditions since the 1970s have been shown to exhibit a linear behavior that directly contradicts what has been expected from the A0 (Overland, 2005). The decade of the 1990s has been regarded as the warmest decade in the last century and current data indicates that the 2000s may be even a warmer decade than the 1990s further supporting the linear variability. In this paper, we use satellite data to gain insights into the warming Arctic and how the abnormally warm conditions during the last few years are reflected in the region.

Comiso, Josefino C.

2005-01-01

65

Naval EarthMap Observer (NEMO) satellite  

NASA Astrophysics Data System (ADS)

The Office of Naval Research (ONR) and the Naval Research Laboratory (NRL) have initiated the Hyperspectral Remote Sensing Technology (HRST) program to demonstrate the utility of a hyperspectral earth-imaging system to support Naval needs for characterization of the littoral regions of the world. One key component of the HRST program is the development of the Naval EarthMap Observer (NEMO) satellite system to provide a large hyperspectral data base. NEMO will carry the Coastal Ocean Imaging Spectrometer (COIS) which will provide images of littoral regions with 210 spectral channels over a bandpass of 0.4 to 2.5 micrometer. Since ocean environments have reflectances typically less than 5%, this system requires a very high signal-to-noise ratio (SNR). COIS will sample over a 30 km swath width with a 60 m Ground Sample Distance (GSD) with the ability to go to a 30 m GSD by utilizing the systems attitude control system to 'nod' (i.e., use ground motion compensation to slow down the ground track of the field of view). Also included in the payload is a co-registered 5 m Panchromatic Imager (PIC) to provide simultaneous high spatial resolution imagery. A sun-synchronous, 97.81 degree inclination, circular orbit of 605 km allows continuous repeat coverage of the whole earth. One unique aspect of NEMO is an on-board processing system, a feature extraction and data compression software package developed by NRL called the Optical Real-Time Spectral Identification System (ORASIS). ORASIS employs a parallel, adaptive hyperspectral method for real time scene characterization, data reduction, background suppression, and target recognition. The use of ORASIS is essential for management of the massive amounts of data expected from the NEMO HSI system, and for developing Naval products under HRST. The combined HSI and panchromatic images will provide critical phenomenology to aid in the operation of Naval systems in the littoral environment. The imagery can also satisfy a number of commercial and science community requirements for moderate spatial and high spectral resolution remote sensing data over land and water. Specific areas of interest for the Navy include bathymetry, water clarity, bottom type, atmospheric visibility, bioluminescence potential, beach characterization, underwater hazards, total column atmospheric water vapor, and detection and mapping of subvisible cirrus. These data support requirements for Joint Strike and Joint Littoral warfare, particularly for environmental characterization of the littoral ocean. Demonstrations of direct downlinking of near real-time data to the warfighter are also being formulated. The NEMO satellite is planned to launch in 2000 followed by an operational period of 3 to 5 years.

Wilson, Thomas L.; Davis, Curtiss O.

1999-10-01

66

Satellite systems for maritime navigation  

NASA Astrophysics Data System (ADS)

The principles underlying the design of Doppler satellite navigation systems are examined, and the characteristics of existing and proposed satellite systems for maritime navigation are described. Particular attention is given to the COSPAS-SARSAT system, GPS/Navstar, and the Navsat, Granas, and Geostar projects. The features of shipboard navigation instruments are examined.

Bogdanov, Valerii Anatol'evich; Sorochinskii, Valentin Alekseevich; Iakshevich, Evgenii Viktorovich

67

Land mobile satellite demonstration system  

NASA Technical Reports Server (NTRS)

A land mobile satellite demonstration system is described. It ulilizes the INMARSAT MARECS B2 satellite at 26 degrees W. The system provides data transmission using a poll-response protocol with error detection and retransmission at 200 b/s rate. For most tests a 1.8 inch monopole antenna was used, along with a satellite EIRP normally used for four voice channels. A brief summary of the results are given and the overall system consisting of three elements in addition to the satellite (the mobile unit, the base station, and the office terminal and map display) is described. Throughput statistics from one trip are summarized.

Gooch, Guy M.; Nicholas, David C.

1988-01-01

68

Applications of Satellite Observations to Aerosol Analyses and Forecasting using the NAAPS Model and the DataFed Distributed Data System  

NASA Astrophysics Data System (ADS)

Near-real-time (NRT) aerosol characterization, forecasting and decision support is now possible through the availability of (1) surface-based monitoring of regional PM concentrations, (2) global-scale columnar aerosol observations through satellites; (3) an aerosol model (NAAPS) that is capable of assimilating NRT satellite observations; and (4) an emerging cyber infrastructure for processing and distribution of data and model results (DataFed) for a wide range of users. This report describes the evolving NRT aerosol analysis and forecasting system and its applications at Federal and State and other AQ Agencies and groups. Through use cases and persistent real-world applications in the US and abroad, the report will show how satellite observations along with surface data and models are combined to aid decision support for AQ management, science and informing the public. NAAPS is the U.S. Navy's global aerosol and visibility forecast model that generates operational six-day global-scale forecasts for sulfate, dust, sea salt, and smoke aerosol. Through NAVDAS-AOD, NAAPS operationally assimilates filtered and corrected MODIS MOD04 aerosol optical depths and uses satellite-derived FLAMBÉ smoke emissions. Washington University's federated data system, DataFed, consist of a (1) data server which mediates the access to AQ datasets from distributed providers (NASA, NOAA, EPA, etc.,); (2) an AQ Data Catalog for finding and accessing data; and (3) a set of application programs/tools for browsing, exploring, comparing, aggregating, fusing data, evaluating models and delivering outputs through interactive visualization. NAAPS and DataFed are components of the Global Earth Observation System of Systems (GEOSS). Satellite data support the detection of long-range transported wind-blown dust and biomass smoke aerosols on hemispheric scales. The AQ management and analyst communities use the satellite/model data through DataFed and other channels as evidence for Exceptional Events (EE) as defined by EPA; i.e., Sahara dust impact on Texas and Florida, local dusts events in the Southwestern U.S. and Canadian smoke events over the Northeastern U.S. Recent applications include the impact analysis of a major Saudi Arabian dust event on Mumbai, India air quality. The NAAPS model and the DataFed tools can visualize the dynamic AQ events as they are manifested through the different sensors. Satellite-derived aerosol observations assimilated into NAAPS provide estimates of daily emission rates for dust and biomass fire sources. Tuning and reconciliation of the observations, emissions and models constitutes a key and novel contribution yielding a convergence toward the true five-dimensional (X, Y, Z, T, Composition) characterization of the atmospheric aerosol data space. This observation-emission-model reconciliation effort is aided by model evaluation tools and supports the international HTAP program. The report will also discuss some of the challenges facing multi-disciplinary, multi-agency, multi-national applications of integrated observation-modeling system of systems that impede the incorporation of satellite observations into AQ management decision support systems.

Husar, R. B.; Hoijarvi, K.; Westphal, D. L.; Scheffe, R.; Keating, T.; Frank, N.; Poirot, R.; DuBois, D. W.; Bleiweiss, M. P.; Eberhard, W. L.; Menon, R.; Sethi, V.; Deshpande, A.

2012-12-01

69

Global canopy interception from satellite observations  

Technology Transfer Automated Retrieval System (TEKTRAN)

A new methodology for retrieving rainfall interception rates from multi satellite observations is presented. The approach makes use of the daily productof the Global Precipitation Climatology Project (GPCP) as driving data and applies Gash’s analytical model to derive interception rates at global sc...

70

Comparison of filter predictions with satellite observations  

SciTech Connect

Satellite observations of meteor entry are used to calibrate a filter model of fragmentation. Predicted sizes and masses compare favorably with data and analytic interpretations for objects of all sizes. However, objects that fragment into many large objects should be treated by the decomposition of the radiation signal into the contributions from the different fragments.

Canavan, G.H.

1997-10-01

71

Applications systems verification and transfer project. Volume 2: Operational applications of satellite snow-cover observations and data-collection systems in the Arizona test site  

NASA Technical Reports Server (NTRS)

Ground surveys and aerial observations were used to monitor rapidly changing moisture conditions in the Salt-Verde watershed. Repetitive satellite snow cover observations greatly reduce the necessity for routine aerial snow reconnaissance flights over the mountains. High resolution, multispectral imagery provided by LANDSAT satellite series enabled rapid and accurate mapping of snow-cover distributions for small- to medium-sized subwatersheds; however, the imagery provided only one observation every 9 days of about a third of the watershed. Low resolution imagery acquired by the ITOSa dn SMS/GOES meteorological satellite series provides the daily synoptic observation necessary to monitor the rapid changes in snow-covered area in the entire watershed. Short term runoff volumes can be predicted from daily sequential snow cover observations.

Schumann, H. H.

1981-01-01

72

CCD astrometric observations of Uranian satellites.  

NASA Astrophysics Data System (ADS)

Astrometric positions of the five largest satellites are given for the oppositions of Uranus for the years 1989 to 1994. These positions were measured on 368 CCD frames obtained at the Cassegrain focus of a 1.6-m reflector. They are compared with the theoretically calculated positions from GUST86 (Laskar & Jacobson 1987). The observed minus calculated residuals referred to Oberon have standard deviations of the order of 0."05 for the three greatest Uranian satellites and 0.07" for Miranda. These residuals are comparable to the best available in the literature.

Veiga, C. H.; Vieira Martins, R.

1995-11-01

73

Astrometric observations of planetary satellites at the Abastumani Astrophysical Observatory  

NASA Astrophysics Data System (ADS)

We present and discuss the results of the astrometry project during which we observed the satellites of Mars, Jupiter, Saturn, Uranus, and Neptune at the Abastumani Astrophysical Observatory (Georgia) between 1983 and 1994. Observations at the Abastumani Observatory were performed with the double Zeiss astrograph (DZA: D/ F = 400/3024 mm) and AZT-11 telescope ( F = 16 m). We processed a large array of observations and determined exact coordinates of the planets and their satellites in a system of reference stars of modern catalogues as well as relative coordinates of the satellites. The results were compared with modern ephemerides using the MULTI-SAT software. The comparison enabled us to estimate the accuracy of observations (their random and systematic uncertainties) and the accuracy of modern theories of the motion of planets and their satellites. Random uncertainties of observations are estimated to be 0.10?-0.40? for various objects and observational conditions. Observational results obtained for Uranus, Neptune and the satellites Titania and Oberon were shown to deviate appreciably and systematically from theories of their motion. The results of observations are presented in the Pulkovo database for Solar System bodies that is available at the website http://www.puldb.ru.

Kiseleva, T. P.; Chanturiya, S. M.; Vasil'eva, T. A.; Kalinichenko, O. A.

2012-11-01

74

Scheduling Earth Observing Satellites with Evolutionary Algorithms  

NASA Technical Reports Server (NTRS)

We hypothesize that evolutionary algorithms can effectively schedule coordinated fleets of Earth observing satellites. The constraints are complex and the bottlenecks are not well understood, a condition where evolutionary algorithms are often effective. This is, in part, because evolutionary algorithms require only that one can represent solutions, modify solutions, and evaluate solution fitness. To test the hypothesis we have developed a representative set of problems, produced optimization software (in Java) to solve them, and run experiments comparing techniques. This paper presents initial results of a comparison of several evolutionary and other optimization techniques; namely the genetic algorithm, simulated annealing, squeaky wheel optimization, and stochastic hill climbing. We also compare separate satellite vs. integrated scheduling of a two satellite constellation. While the results are not definitive, tests to date suggest that simulated annealing is the best search technique and integrated scheduling is superior.

Globus, Al; Crawford, James; Lohn, Jason; Pryor, Anna

2003-01-01

75

Seasonal streamflow estimation employing satellite snowcover observations  

NASA Technical Reports Server (NTRS)

Low resolution meteorological satellite and high resolution earth resources satellite data have been used to map snow covered area over the upper Indus River and the Wind River Mountains of Wyoming, respectively. For the Indus River early spring snow covered area was extracted and related to April through June stream flow from 1967-1971 using a regression equation. Prediction of the April-June 1972 stream flow from the satellite data was within three percent of the actual total. Composited results from two years of data over seven Wind River Mountain watersheds indicated that LANDSAT-1 snow cover observations, separated on the basis of watershed elevation, could also be related to runoff in significant regression equations.

Rango, A.; Salomonson, V. V.; Foster, J. L.

1975-01-01

76

The observation, detection and research on satellites of asteroids  

NASA Technical Reports Server (NTRS)

Evidence is presented for the existence of asteroidal satellites. Instances wherein the occultation of a star occurred when a known asteroid was close to the line of sight of the star are discussed, and the implication that the eclipses were caused by satellites of the asteroids is considered. The role of amateur astronomers in these observations is reviewed, and possible applications of the technique of indirect occultation with regard to the solar system are discussed.

Maley, P. D.

1980-01-01

77

Global Warming: Evidence from Satellite Observations  

NASA Technical Reports Server (NTRS)

Observations made in Channel 2 (53.74 GHz) of the Microwave Sounding Unit (MSU) radiometer, flown on-board sequential, sun-synchronous, polar orbiting NOAA operational satellites, indicate that the mean temperature of the atmosphere over the globe increased during the period 1980 to 1999. In this study we have minimized systematic errors in the time series introduced by the satellite orbital drift in an objective manner. This is done with the help the onboard warm black body temperature, which is used in the calibration of the MSU radiometer. The corrected MSU Channel 2 observations of the NOAA satellite series reveal that the vertically weighted global mean temperature of the atmosphere, with a peak weight near the mid-troposphere, warmed at the rate of 0.13 K per decade (with an uncertainty of 0.05 K per decade) during 1980 to 1999. The global warming deduced from conventional meteorological data that have been corrected for urbanization effects agrees reasonably with this satellite deuced result.

Prabhakara, C.; Iacovazzi, R., Jr.; Yoo, J.-M.

2001-01-01

78

Global Warming: Evidence from Satellite Observations  

NASA Technical Reports Server (NTRS)

Observations made in Channel 2 (53.74 GHz) of the Microwave Sounding Unit (MSU) radiometer, flown onboard sequential, sun-synchronous, polar-orbiting NOAA (National Oceanic and Atmospheric Administration) operational satellites, indicate that the mean temperature of the atmosphere over the globe increased during the period 1980 to 1999. In this study, we have minimized systematic errors in the time series introduced by satellite orbital drift in an objective manner. This is done with the help of the onboard warm-blackbody temperature, which is used in the calibration of the MSU radiometer. The corrected MSU Channel 2 observations of the NOAA satellite series reveal that the vertically-weighted global-mean temperature of the atmosphere, with a peak weight near the mid troposphere, warmed at the rate of 0.13 +/- 0.05 K/decade during 1980 to 1999. The global warming deduced from conventional meteorological data that have been corrected for urbanization effects agrees reasonably with this satellite-deduced result.

Prabhakara, C.; Iacovazzi, R.; Yoo, J.-M.; Dalu, G.; Einaudi, Franco (Technical Monitor)

2000-01-01

79

Globally Gridded Satellite observations for climate studies  

USGS Publications Warehouse

Geostationary satellites have provided routine, high temporal resolution Earth observations since the 1970s. Despite the long period of record, use of these data in climate studies has been limited for numerous reasons, among them that no central archive of geostationary data for all international satellites exists, full temporal and spatial resolution data are voluminous, and diverse calibration and navigation formats encumber the uniform processing needed for multisatellite climate studies. The International Satellite Cloud Climatology Project (ISCCP) set the stage for overcoming these issues by archiving a subset of the full-resolution geostationary data at ~10-km resolution at 3-hourly intervals since 1983. Recent efforts at NOAA's National Climatic Data Center to provide convenient access to these data include remapping the data to a standard map projection, recalibrating the data to optimize temporal homogeneity, extending the record of observations back to 1980, and reformatting the data for broad public distribution. The Gridded Satellite (GridSat) dataset includes observations from the visible, infrared window, and infrared water vapor channels. Data are stored in Network Common Data Format (netCDF) using standards that permit a wide variety of tools and libraries to process the data quickly and easily. A novel data layering approach, together with appropriate satellite and file metadata, allows users to access GridSat data at varying levels of complexity based on their needs. The result is a climate data record already in use by the meteorological community. Examples include reanalysis of tropical cyclones, studies of global precipitation, and detection and tracking of the intertropical convergence zone.

Knapp, K.R.; Ansari, S.; Bain, C.L.; Bourassa, M.A.; Dickinson, M.J.; Funk, C.; Helms, C.N.; Hennon, C.C.; Holmes, C.D.; Huffman, G.J.; Kossin, J.P.; Lee, H.-T.; Loew, A.; Magnusdottir, G.

2011-01-01

80

Communications satellite systems capacity analysis  

NASA Technical Reports Server (NTRS)

Analog and digital modulation techniques are compared with regard to efficient use of the geostationary orbit by communications satellites. Included is the definition of the baseline systems (both space and ground segments), determination of interference susceptibility, calculation of orbit spacing, and evaluation of relative costs. It is assumed that voice or TV is communicated at 14/11 GHz using either FM or QPSK modulation. Both the Fixed-Satellite Service and the Broadcasting-Satellite Service are considered. For most of the cases examined the digital approach requires a satellite spacing less than or equal to that required by the analog approach.

Browne, L.; Hines, T.; Tunstall, B.

1982-01-01

81

Simulated NASA Satellite Data Products for the NOAA Integrated Coral Reef Observation Network/Coral Reef Early Warning System  

NASA Technical Reports Server (NTRS)

This RPC (Rapid Prototyping Capability) experiment will demonstrate the use of VIIRS (Visible/Infrared Imager/Radiometer Suite) and LDCM (Landsat Data Continuity Mission) sensor data as significant input to the NOAA (National Oceanic and Atmospheric Administration) ICON/ CREWS (Integrated Coral Reef Observation System/Coral Reef Early Warning System). The project affects the Coastal Management Program Element of the Applied Sciences Program.

Estep, Leland; Spruce, Joseph P.

2007-01-01

82

Offshore wind resource mapping using satellite observations  

NASA Astrophysics Data System (ADS)

Offshore wind mapping using satellite observations has been developed in the last decade. The archives of scatterometer and SAR images useful for ocean wind mapping contain data from around 8 to 15 years. For the statistical analysis it is important to include high numbers of observations. For scatterometer the wind resource analysis can be done based on around 6.500 individual readings, i.e. two observations daily since July 1999. Comparison results between meteorological observations at the Horns Rev offshore wind farm has been shown to compare well with QuikSCAT winds. Also SAR-based wind mapping has been compared to the same observations with good results. At present new analysis using more observations, available through the ESA EO Scandia-SAR project, show new maps of offshore winds in the North Sea and Baltic Sea. During year 2009 the first analysis for the new EU-Norsewind project (2008-2012) will be conducted. This project aims to map wind resource for a large offshore region in Northern Europe based on satellite, lidar and masts offshore.

Hasager, C. B.; Badger, M.

2009-04-01

83

Feasibility of tropical cyclone intensity estimation using satellite-borne radiometer measurements: An observing system simulation experiment  

E-print Network

This study evaluates the potential of a proposed technique in using satellite-borne radiometer measurements and weather analyses to estimate the intensity of tropical cyclones. This theory shows that intensity is essentially ...

Sieron, Scott B.

84

Satellite observations of transionospheric pulse pairs  

SciTech Connect

The BLACKBEARD payload aboard the ALEXIS satellite has been making broadband observations in the VHF band of the radio spectrum. Since November of 1993 several hundred unusual signals have been recorded. The peculiar nature of these bursts of radio noise is that they have a duration of approximately 10 {mu}sec, are typically 20 to 40 dB brighter than the average background, and occur in pairs separated by approximately 50 {mu}sec. The authors have dubbed these emissions TransIonospheric Pulse Pairs, or TIPP events. They do not know what the source of these emissions is, but the dispersion of these signals is consistent with an origin at or near the earth`s surface. The satellite field of view and time of day when TIPP events are generally detected are consistent with regions of thunderstorm activity such as south-central Africa or Indonesia. 4 refs., 5 figs.

Holden, D.N.; Munson, C.P.; Devenport, J.C. [Los Alamos National Lab., NM (United States)] [Los Alamos National Lab., NM (United States)

1995-04-15

85

Geostationary satellite observations of dynamic phytoplankton photophysiology  

NASA Astrophysics Data System (ADS)

June 2010, the Geostationary Ocean Color Imager (GOCI) has been collecting the first diurnally resolved satellite ocean measurements. Here GOCI retrievals of phytoplankton chlorophyll concentration and fluorescence are used to evaluate daily to seasonal changes in photophysiological properties. We focus on nonphotochemical quenching (NPQ) processes that protect phytoplankton from high light damage and cause strong diurnal cycles in fluorescence emission. This NPQ signal varies seasonally, with maxima in winter and minima in summer. Contrary to expectations from laboratory studies under constant light conditions, this pattern is highly consistent with an earlier conceptual model and recent field observations. The same seasonal cycle is registered in fluorescence data from the polar-orbiting Moderate Resolution Imaging Spectroradiometer Aqua satellite sensor. GOCI data reveal a strong correlation between mixed layer growth irradiance and fluorescence-derived phytoplankton photoacclimation state that can provide a path for mechanistically accounting for NPQ variability and, subsequently, retrieving information on iron stress in global phytoplankton populations.

O'Malley, Robert T.; Behrenfeld, Michael J.; Westberry, Toby K.; Milligan, Allen J.; Shang, Shaoling; Yan, Jing

2014-07-01

86

Evolution of the Loop Current System During the Deepwater Horizon Oil Spill Event as Observed With Drifters and Satellites  

E-print Network

Evolution of the Loop Current System During the Deepwater Horizon Oil Spill Event as Observed]. Thus, during the Deepwater Horizon spill event, a critical question was whether the oil would the Deepwater Horizon Oil Spill: A Record-Breaking Enterprise Geophysical Monograph Series 195 Copyright 2011

Meyers, Steven D.

87

Students as Ground Observers for Satellite Cloud Retrieval Validation  

NASA Technical Reports Server (NTRS)

The Students' Cloud Observations On-Line (S'COOL) Project was initiated in 1997 to obtain student observations of clouds coinciding with the overpass of the Clouds and the Earth's Radiant Energy System (CERES) instruments on NASA's Earth Observing System satellites. Over the past seven years we have accumulated more than 9,000 cases worldwide where student observations are available within 15 minutes of a CERES observation. This paper reports on comparisons between the student and satellite data as one facet of the validation of the CERES cloud retrievals. Available comparisons include cloud cover, cloud height, cloud layering, and cloud visual opacity. The large volume of comparisons allows some assessment of the impact of surface cover, such as snow and ice, reported by the students. The S'COOL observation database, accessible via the Internet at http://scool.larc.nasa.gov, contains over 32,000 student observations and is growing by over 700 observations each month. Some of these observations may be useful for assessment of other satellite cloud products. In particular, some observing sites have been making hourly observations of clouds during the school day to learn about the diurnal cycle of cloudiness.

Chambers, Lin H.; Costulis, P. Kay; Young, David F.; Rogerson, Tina M.

2004-01-01

88

Satellite dual antenna pointing system  

NASA Technical Reports Server (NTRS)

A satellite antenna pointing system for separately pointing separated transmit and receive high gain antenna systems includes means for separately and sequentially applying a beacon signal to the transmit and receive antenna systems and a broad beam width antenna which has a coverage area greater than the overall coverage region of the spot beam antenna systems. The system includes ground stations located at or near the periphery of the overall coverage region adapted to receive these beacon signals. At a central control station these beacon signals are compared to provide first signals proportional to the ratio of said beacon signals received from said transmit antenna system and said broad beam width antenna and second signals proportional to the ratio of said beacon signals received from said satellite receive antenna system and said broad beam width antenna. The central station generates from said first signals transmit antenna control signals which are sent to the satellite to control the orientation of said transmit antenna system. Likewise, the central control station generates from the second signals receiver antenna control signals which are applied to the satellite to control the orientation of the satellite receive antenna system.

Keigler, John E. (Inventor); Hartshorne, Frank A. (Inventor)

1986-01-01

89

Meteorological Satellites (METSAT) and Earth Observing System (EOS) Advanced Microwave Sounding Unit-A (AMSU-A) Failure Modes and Effects Analysis (FMEA) and Critical Items List (CIL)  

NASA Technical Reports Server (NTRS)

This Failure Modes and Effects Analysis (FMEA) is for the Advanced Microwave Sounding Unit-A (AMSU-A) instruments that are being designed and manufactured for the Meteorological Satellites Project (METSAT) and the Earth Observing System (EOS) integrated programs. The FMEA analyzes the design of the METSAT and EOS instruments as they currently exist. This FMEA is intended to identify METSAT and EOS failure modes and their effect on spacecraft-instrument and instrument-component interfaces. The prime objective of this FMEA is to identify potential catastrophic and critical failures so that susceptibility to the failures and their effects can be eliminated from the METSAT/EOS instruments.

1996-01-01

90

Middle atmosphere composition revealed by satellite observations  

NASA Technical Reports Server (NTRS)

A series of plots that describe the state of the stratosphere and to some degree, the mesosphere as revealed by satellite observations are shown. The pertinent instrument features, spatial and temporal coverage, and details of accuracy and precision for the experiments providing the data were described. The main features of zonal mean cross sections and polar stereographic projections were noted and intercomparisons were discussed where a parameter was measured by more than one experiment. The main purpose was to collect the available data in one place and provide enough inforamation on limitations or cautions about the data so that they could be used in model comparisons and science studies.

Russell, J. M., III; Solomon, S.; Mccormick, M. P.; Miller, A. J.; Barnett, J. J.; Jones, R. L.; Rusch, D. W.

1986-01-01

91

Observe animated satellite images of water vapor  

NSDL National Science Digital Library

This animation shows Earth science students how jet streams drive the movement of water vapor in the atmosphere. The introduction explains how the infrared images were taken from a satellite positioned about 8 kilometers above the Earth's surface. Students are instructed to observe how the jet streams (indicated by dark areas) are juxtaposed against areas of dense water vapor (indicated by light areas). Movie controls allow students to repeat, pause, or step through the animation, which can give students more time to analyze the images. Copyright 2005 Eisenhower National Clearinghouse

Education, Terc. C.; Littell, Mcdougal

2003-01-01

92

Advanced satellite communication system  

NASA Technical Reports Server (NTRS)

The objective of this research program was to develop an innovative advanced satellite receiver/demodulator utilizing surface acoustic wave (SAW) chirp transform processor and coherent BPSK demodulation. The algorithm of this SAW chirp Fourier transformer is of the Convolve - Multiply - Convolve (CMC) type, utilizing off-the-shelf reflective array compressor (RAC) chirp filters. This satellite receiver, if fully developed, was intended to be used as an on-board multichannel communications repeater. The Advanced Communications Receiver consists of four units: (1) CMC processor, (2) single sideband modulator, (3) demodulator, and (4) chirp waveform generator and individual channel processors. The input signal is composed of multiple user transmission frequencies operating independently from remotely located ground terminals. This signal is Fourier transformed by the CMC Processor into a unique time slot for each user frequency. The CMC processor is driven by a waveform generator through a single sideband (SSB) modulator. The output of the coherent demodulator is composed of positive and negative pulses, which are the envelopes of the chirp transform processor output. These pulses correspond to the data symbols. Following the demodulator, a logic circuit reconstructs the pulses into data, which are subsequently differentially decoded to form the transmitted data. The coherent demodulation and detection of BPSK signals derived from a CMC chirp transform processor were experimentally demonstrated and bit error rate (BER) testing was performed. To assess the feasibility of such advanced receiver, the results were compared with the theoretical analysis and plotted for an average BER as a function of signal-to-noise ratio. Another goal of this SBIR program was the development of a commercial product. The commercial product developed was an arbitrary waveform generator. The successful sales have begun with the delivery of the first arbitrary waveform generator.

Staples, Edward J.; Lie, Sen

1992-01-01

93

The American mobile satellite system  

NASA Astrophysics Data System (ADS)

During 1989, the American Mobile Satellite Corporation (AMSC) was authorized to construct, launch, and operate satellites to provide mobile satellite services (MSS) to the U.S. and Puerto Rico. The AMSC has undertaken three major development programs to bring a full range of MSS services to the U.S. The first program is the space segment program that will result in the construction and launch of the satellites as well as the construction and installation of the supporting ground telemetry and command system. The second segment will result in the specification, design, development, construction, and installation of the Network Control System necessary for managing communications access to the satellites, and the specification and development of ground equipment for standard circuit switched and packet switched communications services. The third program is the Phase 1 program to provide low speed data services within the U.S. prior to availability of the AMSC satellites and ground segment. Described here are the present status and plans for these three programs as well as an update on related business arrangements and regulatory matters.

Garner, William B.

94

The American mobile satellite system  

NASA Technical Reports Server (NTRS)

During 1989, the American Mobile Satellite Corporation (AMSC) was authorized to construct, launch, and operate satellites to provide mobile satellite services (MSS) to the U.S. and Puerto Rico. The AMSC has undertaken three major development programs to bring a full range of MSS services to the U.S. The first program is the space segment program that will result in the construction and launch of the satellites as well as the construction and installation of the supporting ground telemetry and command system. The second segment will result in the specification, design, development, construction, and installation of the Network Control System necessary for managing communications access to the satellites, and the specification and development of ground equipment for standard circuit switched and packet switched communications services. The third program is the Phase 1 program to provide low speed data services within the U.S. prior to availability of the AMSC satellites and ground segment. Described here are the present status and plans for these three programs as well as an update on related business arrangements and regulatory matters.

Garner, William B.

1990-01-01

95

Satellite Application for Disaster Management Information Systems  

NASA Astrophysics Data System (ADS)

Abstract Satellites are becoming increasingly vital to modern day disaster management activities. Earth observation (EO) satellites provide images at various wavelengths that assist rapid-mapping in all phases of the disaster management cycle: mitigation of potential risks in a given area, preparedness for eventual disasters, immediate response to a disaster event, and the recovery/reconstruction efforts follo wing it. Global navigation satellite systems (GNSS) such as the Global Positioning System (GPS) assist all the phases by providing precise location and navigation data, helping manage land and infrastructures, and aiding rescue crews coordinate their search efforts. Effective disaster management is a complex problem, because it involves many parameters, which are usually not easy to measure and even identify: Analysis of current situation, planning, optimum resource management, coordination, controlling and monitoring current activities and making quick and correct decisions are only some of these parameters, whose complete list is very long. Disaster management information systems (DMIS) assist disaster management to analyse the situation better, make decisions and suggest further actions following the emergency plans. This requires not only fast and thorough processing and optimization abilities, but also real-time data provided to the DMIS. The need of DMIS for disaster’s real-time data can be satisfied by small satellites data utilization. Small satellites can provide up-to-data, plus a better media to transfer data. This paper suggests a rationale and a framework for utilization of small Satellite data by DMIS. DMIS should be used ‘’before’’, ‘’during’’ and ‘’after’’ the disasters. Data provided by the Small Satellites are almost crucial in any period of the disasters, because early warning can save lives, and satellite data may help to identify disasters before they occur. The paper also presents’ ‘when’’, ‘’where’’ and ‘’how’’ small satellite data should be used by DMIS.

Okpanachi, George

96

The NOAA-NASA Operational System for Near-Real-Time Volcanic Eruption Detection via Satellite Observations  

Microsoft Academic Search

The Ozone Monitoring Instrument (OMI) on the NASA EOS\\/Aura research satellite allows measurement of SO2 concentrations at UV wavelengths with daily global coverage. SO2 is detected from space using its strong absorption band structure in the near UV (300-320 nm) as well as in IR bands near 7.3 and 8.6 mm. UV SO2 measurements are very robust and are insensitive

G. Vicente; G. Serafino; A. Krueger; W. Schroeder; S. Carn; K. Yang; N. Krotkov; M. Guffanti; P. Levett

2009-01-01

97

Geostar Radio Determination Satellite System  

NASA Astrophysics Data System (ADS)

The Geostar Radio Determination Satellite System is designed to provide accurate position information and ancillary message passing capability for land mobile, marine, and aeronautical users in the United States and eventually worldwide. The Geostar system is a random access spread spectrum system capable of high positioning accuracy. Geostar can support a large population of users operating inexpensive transceivers. This paper examines the Geostar system positioning technique, error sources, anticipated accuracy, and potential applications.

Richards, Robert T.

98

Satellite observation of atmospheric nuclear gamma radiation  

NASA Technical Reports Server (NTRS)

Satellite observations of the spectrum of gamma radiation from the earth's atmosphere in the energy interval from 300 keV to 8.5 MeV were obtained with a gamma-ray spectrometer during 1980-1983. A total of 20 atmospheric line features are superimposed on a continuum background which is modeled using a power law with an index of -1.16. The line energies and intensities are consistent with production by secondary neutrons interacting with atmospheric N-14 and O-16. The intensity and spectrum of photons at energies below the 511-keV line, in excess of a power law continuum, are explained by Compton scattering of the annihilation line photons in traversing an average of 21 g/sq cm of atmosphere.

Letaw, John R.; Share, G. H.; Kinzer, R. L.; Silberberg, R.; Chupp, E. L.

1989-01-01

99

Advances in Satellite Observations of Earth's Radiation Budget  

NASA Astrophysics Data System (ADS)

The first observation of Earth's radiation budget from satellite dates back to the beginning of the satellite era in late 1950s, when the first satellite images of the planet were recorded. With each passing decade since then, the science community has made advances in instrument technology that has led to a wealth of new information about the sunlight reaching Earth, Earth's albedo, and the emission of thermal radiation to space. Until recently, however, most of the observational breakthroughs were limited to Earth's top-of-atmosphere (TOA) radiation budget. The recent arrival of instruments flown under the Earth Observing System (EOS) and the A-Train constellation of satellites has dramatically changed this situation, providing new opportunities to synergistically combine an array of diverse passive and active satellite instruments to more accurately determine Earth's surface radiation budget. The new data have led to renewed discussions about our basic understanding of Earth's water and energy cycles. The goal of this presentation is to discuss how the new satellite instrument capabilities are being used by the Clouds and the Earth's Radiant Energy (CERES) science team to provide improved observations of the TOA, surface and within-atmosphere radiation budgets and the role clouds play in modulating the energy flows. We focus on the CERES TOA and surface Energy Balanced and Filled (EBAF) product, which combines information from CERES, MODIS, CALIPSO, Cloudsat, AIRS, and geostationary observations all integrated in a consistent manner, and demonstrate how synergistic use of these datasets leads to improved radiative fluxes when compared with surface radiation measurements from the Baseline Surface Radiation Network (BSRN), NOAA SURFRAD, and ARM. We find that EBAF-SFC reduces the bias in surface SW downward flux by a factor of 2 compared to other satellite-based surface radiation budget datasets, show marked reductions in surface downward longwave radiation biases over polar regions, and provide consistent interannual variations in surface radiation compared to ground measurements. We use a new approach to explore how cloud radiative effects at the TOA, surface and within the atmosphere respond to variations in large large-scale atmospheric circulation strength using reanalysis data and CERES EBAF-TOA and EBAF-SFC. Results show remarkably robust relationships between observed variations in the strength of the large-scale Hadley circulation and cloud radiative effects in both ascending and descending branches, providing confidence that continued monitoring of the climate system with climate-quality observations will provide critical constraints on the cloud radiative response to future changes in large-scale atmospheric circulation patterns.

Loeb, N. G.; Kato, S.; Rose, F. G.; Rutan, D. A.

2013-05-01

100

Ocean observing satellite study: instrument and satellite constellation architecture options  

NASA Technical Reports Server (NTRS)

This paper provides: (1) an overview of the set of active and passive instruments identified by the IPO designed to make the ocean measurements including visible and infrared medium and high resolution imagers, radiometers, altimeters, and synthetic aperture radars and (2) the instrument and satellite constellation architecture options studied, and their ability to meet the set of measurement requirements.

Gerber, A. J.; McGuire, J.; Cunningham, J. D.; Pichel, W. G.

2002-01-01

101

Use of Earth Observing Satellites for Operational Hazard Support  

NASA Astrophysics Data System (ADS)

The National Oceanic and Atmospheric Administration (NOAA) relies on Earth observing satellite data to carry out its operational mission to monitor, predict, and assess changes in the Earth's atmosphere, land, and oceans. NOAA's National Environmental Satellite, Data, and Information Service (NESDIS) uses satellite data to help lessen the impacts of natural and man-made disasters due to tropical cyclones, flash floods, heavy snowstorms, volcanic ash clouds (for aviation safety), sea ice (for shipping safety), and harmful algal blooms. Communications systems on NOAA satellites are used to support search and rescue and to relay data from data collection platforms to a variety of users. NOAA's Geostationary (GOES) and Polar (POES) Operational Environmental Satellites are used in conjunction with other satellites to support NOAA's operational mission. While NOAA's National Hurricane Center is responsible for predicting tropical cyclones affecting the U.S. mainland, NESDIS continuously monitors the tropics world wide, relaying valuable satellite interpretations of tropical systems strength and position to users throughout the world. Text messages are sent every six hours for tropical cyclones in the Western Pacific, South Pacific, and Indian Oceans. To support the monitoring, prediction, and assessment of flash floods and winter storms, NESDIS sends out text messages alerting U.S. weather forecast offices whenever NOAA satellite imagery indicates the occurrence of heavy rain or snow. NESDIS also produces a 24-hour rainfall composite graphic image covering those areas affected by heavy precipitation. The International Civil Aviation Organization (ICAO) and other aviation concerns recognized the need to keep aviators informed of volcanic hazards. To that end, nine Volcanic Ash Advisory Centers (VAAC's) were created to monitor volcanic ash plumes within their assigned airspace. NESDIS hosts one of the VAAC's. Although the NESDIS VAAC's primary responsibility is the continental U.S., Carribean, and adjacent oceans, it also tracks volcanic eruptions throughout the world. Text messages are produced along with graphic interpretations. This information, along with volcanic ash forecasts produced by NOAA's National Weather Service, is made available to U.S. Government and international agencies concerned with aviation, seismology, and climate analysis. Earth observing satellites help NESDIS to ensure safe navigation of ships through sea ice by measuring the extent, thickness, and age of ice as well as sea surface winds over the polar regions of the globe, coastal areas, and inland waterways. These satellites also help NESDIS to monitor U.S. coastal areas for dangerous algal blooms or other toxic effects to fish and sea mammals as well as monitoring floods and fires. Experimental fire products can help in the monitoring of fires and fire weather, as well as determining fire risk. Experimental soil moisture products support flood and drought monitoring. Flood extent and damage assessment for a variety of hazards can be determined from several satellites at varying spatial resolutions. The Search and Rescue Satellite Aided Tracking (SARSAT) system detects and locates persons in distress on land or water. NOAA satellites relay distress signals from emergency beacons through a network of ground stations to the U.S. Mission Control Center (USMCC). The USMCC processes the data and alerts the appropriate search and rescue authorities. SARSAT is part of the international Cospas-Sarsat Program. NOAA's GOES Data Collection (DCS) and Argos (jointly with the French space agency) POES Data Collection and Locations Systems transmit data collected from remote land and water based platforms and distributes the data to researchers, governmental and environmental organizations worldwide. The GOES DCS system allows near real time and frequent transmissions, e.g. hourly, over the Americas and much of the Atlantic and Eastern Pacific Oceans. ARGOS transmissions are less frequent, but global and provide the location of moving platforms such as animals and d

Wood, H. M.; Lauritson, L.

102

Civil satellite navigation and location systems  

NASA Astrophysics Data System (ADS)

The use of satellites for civil navigation and location, including satellites not necessarily launched for that purpose, is reviewed. In particular, attention is given to differences between civil and military satellites; civil use of military systems and the associated commercial considerations and regulatory issues; the use of communication satellites; and radiodetermination satellite service based on geostationary satellites. The discussion also covers integration with ground-based radio-navigation systems; existing radio-navigation satellite systems; and the Starfix, Geostar/Locstar, Starfind, Navsat, and Rexstar systems.

Blanchard, W. F.

1989-05-01

103

Monitoring the Climate System with Satellites  

NSDL National Science Digital Library

The international science community has identified a set of Essential Climate Variables (ECVs) that should be monitored for measuring the climate system, how it is changing, and its likely impact on future climate. Environmental satellites play an important role in this effort. They are uniquely positioned to provide broad, spatially consistent, and continuous global sampling of many of the ECVs. This module explores the benefits of monitoring the climate system with satellites. We begin by reviewing how satellites observe key atmospheric elements and features that are found in a variety of climate cycles and are important for studying long-term climate trends. From there, we explore events at the different scales (from seasonal to long-term) and the contributions that satellites make to improving our understanding, monitoring, and prediction of them. Finally, we discuss the challenges involved in monitoring climate with satellites. Among these is the need for continuous, stable, high-resolution, and validated measurements that are coordinated with the worldâs satellite operators.

Comet

2012-01-10

104

Morelos Satellite System for Mexico  

NASA Astrophysics Data System (ADS)

The telephone, television, and data communication services that the Morelos Satellite System (MSS) provides are discussed. The design and functions of the MSS which consists of two geosynchronous communication satellites that operate in C and Ku frequency bands and are located at 113.5 deg and 116.5 deg W longitude are described. The capabilities of the antenna, communication, attitude control, telemetry, command, reaction control, electrical power, and thermal control subsystems are studied. The components of the earth station are examined. The economic and social benefits possible from the application of the MSS to banking, rural clinics, food distribution services, and the oil and electric industries are analyzed.

Sanchez Ruiz, M. E.

1986-03-01

105

Inferring Land Surface Model Parameters for the Assimilation of Satellite-Based L-Band Brightness Temperature Observations into a Soil Moisture Analysis System  

NASA Technical Reports Server (NTRS)

The Soil Moisture and Ocean Salinity (SMOS) satellite mission provides global measurements of L-band brightness temperatures at horizontal and vertical polarization and a variety of incidence angles that are sensitive to moisture and temperature conditions in the top few centimeters of the soil. These L-band observations can therefore be assimilated into a land surface model to obtain surface and root zone soil moisture estimates. As part of the observation operator, such an assimilation system requires a radiative transfer model (RTM) that converts geophysical fields (including soil moisture and soil temperature) into modeled L-band brightness temperatures. At the global scale, the RTM parameters and the climatological soil moisture conditions are still poorly known. Using look-up tables from the literature to estimate the RTM parameters usually results in modeled L-band brightness temperatures that are strongly biased against the SMOS observations, with biases varying regionally and seasonally. Such biases must be addressed within the land data assimilation system. In this presentation, the estimation of the RTM parameters is discussed for the NASA GEOS-5 land data assimilation system, which is based on the ensemble Kalman filter (EnKF) and the Catchment land surface model. In the GEOS-5 land data assimilation system, soil moisture and brightness temperature biases are addressed in three stages. First, the global soil properties and soil hydraulic parameters that are used in the Catchment model were revised to minimize the bias in the modeled soil moisture, as verified against available in situ soil moisture measurements. Second, key parameters of the "tau-omega" RTM were calibrated prior to data assimilation using an objective function that minimizes the climatological differences between the modeled L-band brightness temperatures and the corresponding SMOS observations. Calibrated parameters include soil roughness parameters, vegetation structure parameters, and the single scattering albedo. After this climatological calibration, the modeling system can provide L-band brightness temperatures with a global mean absolute bias of less than 10K against SMOS observations, across multiple incidence angles and for horizontal and vertical polarization. Third, seasonal and regional variations in the residual biases are addressed by estimating the vegetation optical depth through state augmentation during the assimilation of the L-band brightness temperatures. This strategy, tested here with SMOS data, is part of the baseline approach for the Level 4 Surface and Root Zone Soil Moisture data product from the planned Soil Moisture Active Passive (SMAP) satellite mission.

Reichle, Rolf H.; De Lannoy, Gabrielle J. M.

2012-01-01

106

Temporal and spatial variations of global deep cloud systems based on CloudSat and CALIPSO satellite observations  

NASA Astrophysics Data System (ADS)

The spatial and temporal global distribution of deep clouds was analyzed using a four-year dataset (2007-10) based on observations from CloudSat and CALIPSO. Results showed that in the Northern Hemisphere, the number of deep cloud systems (DCS) reached a maximum in summer and a minimum in winter. Seasonal variations in the number of DCS varied zonally in the Southern Hemisphere. DCS occurred most frequently over central Africa, the northern parts of South America and Australia, and Tibet. The mean cloud-top height of deep cloud cores (TDCC) decreased toward high latitudes in all seasons. DCS with the highest TDCC and deepest cores occurred over east and south Asian monsoon regions, west-central Africa and northern South America. The width of DCS (WDCS) increased toward high latitudes in all seasons. In general, DCS were more developed in the horizontal than in the vertical direction over high latitudes and vice versa over lower latitudes. Findings from this study show that different mechanisms are behind the development of DCS at different latitudes. Most DCS at low latitudes are deep convective clouds which are highly developed in the vertical direction but cover a relatively small area in the horizontal direction; these DCS have the highest TDCC and smallest WDCS. The DCS at midlatitudes are more likely to be caused by cyclones, so they have less vertical development than DCS at low latitudes. DCS at high latitudes are mainly generated by large frontal systems, so they have the largest WDCS and the smallest TDCC.

Peng, Jie; Zhang, Hua; Li, Zhanqing

2014-05-01

107

Multi-Satellite Observations of Oceanic Lightning  

NASA Technical Reports Server (NTRS)

This paper will present several case studies of active oceanic lightning storms. Measurements by instruments on the Tropical Rainfall Measuring Mission (TRMM) and Fast On-orbit Recording of Transient Events (FORTE) platforms demonstrate that the two sets of sensors reinforce and complement one another. There is spatial and temporal coincidence between the optical data sets from Lightning Imaging Sensor (LIS) on TRMM and the photo-diode detector on FORTE. The LIS flash analysis provides a framework to interpret the stroke level data from FORTE. For these cases, the VHF receiver on FORTE is slaved to the optical system to provide stroke level radio frequency (RF) diagnostics. The occasions when TRMM and FORTE simultaneously have a lightning storm in their overlapping fields of view are extremely rare. One case study in the Gulf of Mexico is within range of land based sensor networks. These networks confirm the interpretation of satellite data and well as provide context for the storm conditions.

Boeck, W. L.; Jacobson, A. R.; Christian, H. J.; Goodman, S. J.

2003-01-01

108

Global Precipitation Analysis Using Satellite Observations  

NASA Technical Reports Server (NTRS)

Global precipitation analysis covering the last few decades and the impact of the new TRMM (Tropical Rainfall Measuring Mission) observations are reviewed in the context of weather and climate applications. All the data sets discussed are the result of mergers of information from multiple satellites and gauges, where available. The focus of the talk is on TRMM-based 3 hr. analyses that use TRMM to calibrate polar-orbit microwave observations from SSM/I (and other satellites) and geosynchronous IR observations and merges the various calibrated observations into a final, 3 hr. resolution map. This TRMM standard product will be available for the entire TRMM period (January 1998-present) at the end of 2002. A real-time version of this merged product is being produced and is available at 0.25 deg latitude-longitude resolution over the latitude range from 50 deg N-50 deg S. Examples will be shown, including its use in monitoring flood conditions and in relating weather-scale patterns to climate-scale patterns. The 3-hourly analysis is placed in the context of two research products of the World Climate Research Program's (WCRP/GEWEX) Global Precipitation Climatology Project (GPCP). The first is the 23 year, monthly, globally complete precipitation analysis that is used to explore global and regional variations and trends and is compared to the much shorter TRMM tropical data set. The GPCP data set shows no significant global trend in precipitation over the twenty years, unlike the positive trend in global surface temperatures over the past century. Regional trends are also analyzed. A trend pattern that is a combination of both El Nino and La Nina precipitation features is evident in the Goodyear data set. This pattern is related to an increase with time in the number of combined months of El Nino and La Nina during the 23 year period. Monthly anomalies of precipitation are related to ENSO variations with clear signals extending into middle and high latitudes of both hemispheres. Also shown is the GPCP daily, 1 deg latitude-longitude analysis, which is available from January 1997 to the present. Plans to incorporate the TRMM data and 3-hourly analysis into the GPCP products are outlined. The outcome should be an improved global analysis and climatology on monthly scales for the 23 year period and finer time scale analyses for more recent periods, including real-time 3-hourly (or finer) analyses over much of the globe.

Adler, Robert F.; Huffman, George; Curtis, Scott; Bolvin, David; Nelkin, Eric

2002-01-01

109

The Mexican national satellite system  

NASA Astrophysics Data System (ADS)

The satellites, tracking, telemetry, command, and monitoring facilities, and the earth station complex for the Mexican national satellite system, Morelos, are described. The spacecraft are intended to provide educational television, rural telephony, data transmission, and business and industrial services. Scheduled for 1985 launch, the satellites will be placed in GEO and use the C and Ku bands with 12 narrow band and six wideband transponders. Spin-stabilized and solar cell powered, the functional mass will be 666 kg, including propellant. The solar panels will provide 940 W of power and 830 W will be available from NiCd batteries during eclipse conditions. The earth station will be located at Iztapalapa, which will have a 12 m antenna, redundant uplink and downlink radios, and command and ranging equipment. Back-up capability will be provided by a station at Tulancingo. Ku band and C band stations are in planning.

Sanchez Ruiz, M. E.; Briskman, R. D.

1983-10-01

110

Using the JPL Tropical Cyclone Information System to study the climatology of hurricane precipitation structure from 10 years of passive microwave satellite observations in the Atlantic  

NASA Astrophysics Data System (ADS)

In spite of recent improvements in hurricane track forecast accuracy, currently there are still many unanswered questions about the physical processes that determine hurricane genesis, and evolution. Furthermore, a significant amount of work remains to be done in validating and improving hurricane forecast models. None of this can be accomplished without a comprehensive set of multi-parameter observations that are relevant to both the large-scale and the storm-scale processes in the atmosphere and in the ocean. Despite the significant amount of satellite observations today, they are still underutilized in hurricane research and operations, due to complexity and volume. To facilitate hurricane research, we developed the JPL Tropical Cyclone Information System (TCIS) of multi-instrument satellite observations pertaining to: i) the thermodynamic and microphysical structure of the storms; ii) the air-sea interaction processes; iii) the larger-scale environment as depicted by the SST and the Total Precipitable Water of the environment (Hristova-Veleva et al., 2008, 2011). Our goal was to create a one-stop place to provide the researchers with an extensive set of observed hurricane data, and their graphical representation, organized in an easy way to determine when coincident observations from multiple instruments are available. In this study we use the 10+ years of passive microwave observations of Atlantic hurricanes to create composite structures that are segregated by hurricane category and by intensification rate. The use of composite structures provides a statistically robust framework (e.g. Rogers et al., 2012). We analyze the storm asymmetry as depicted by several factors - brightness temperatures and their derivatives such as a newly-develop Rain Indicator and a new convective/stratiform separation that is based on the value and the spatial variability of this Rain Indicator. The goal is to determine whether the storm morphology (in particular, the storm asymmetry or lack thereof) carries predictive skills regarding the potential for intensification. The presentation will describe the JPL TCIS and the results of our analysis of the passive microwave satellite observations of the Atlantic hurricanes. Refernces: Hristova-Veleva, S. M., C. Ao, Y. Chao, V. Dang, R. Fovell, M. Garay, Z. Haddad, B. Knosp, B. Lambrigtsen, P. P. Li, K. J. Park, W. Poulsen, H. Su, S. Tanelli, D. Vane, Q. A. Vu, J. Willis, D. L. Wu, 2008: "Using the JPL Tropical Cyclone Information System for Research and Applications", AMS 28th Hurricane and Tropical Meteorology Conference, Orlando, FL, 28Apr.-02May 2008 Hristova-Veleva, S. M., A. Chau, Z. Haddad, B. Knosp, B. Lambrigtsen, P. P. Li, E. Rodriguez, T. -. P. Shen, B. Stiles, H. Su, J. Turk, and Q. Vu, 2011: "Impact of microphysical parameterizations on the structure and intensity of simulated hurricanes: Using satellite data to determine the parameterizations that produce most realistic storms", 14th Conference on Mesoscale Processes, 1-4 August 2011, Los Angeles, California Rogers, R., S. Lorsolo, P. Reasor, J. Gamache, F. Marks, 2012: Multiscale Analysis of Tropical Cyclone Kinematic Structure from Airborne Doppler Radar Composites. Mon. Wea. Rev., 140, 77-99.

Hristova-Veleva, Svetla; Haddad, Ziad; Knosp, Brian; Lambrigtsen, Bjorn; Li, P. Peggy; Poulsen, William; Seo, Eun-Kyoung; Shen, Tsae-Pyng; Turk, Francis J.; Vu, Quoc

2013-04-01

111

Satellite laser ranging observations at Shanghai Astronomical Observatory in 2003  

NASA Astrophysics Data System (ADS)

This is a report of satellite laser ranging observations at Shanghai Observatory in 2003. The total 1650 passes and 1251197 observations for 25 satellites were obtained. In 2003, we made two experiments; one was the laser observation of the "Shen Zhou IV" orbital module, another was the laser observation to low orbit satellites with two-wavelengths (532nm and 683nm) produced by Raman shift.

Yang, Fumin; Zhang, Zhongping; Chen, Wanzhen; Chen, Juping

112

Earth Observing System/Meteorological Satellite (EOS/METSAT). Advanced Microwave Sounding Unit-A (AMSU-A) Contamination Control Plan  

NASA Technical Reports Server (NTRS)

This Contamination Control Plan is submitted in response the Contract Document requirements List (CDRL) 007 under contract NAS5-32314 for the Earth Observing System (EOS) Advanced Microwave Sounding Unit A (AMSU-A). In response to the CDRL instructions, this document defines the level of cleanliness and methods/procedures to be followed to achieve adequate cleanliness/contamination control, and defines the required approach to maintain cleanliness/contamination control through shipping, observatory integration, test, and flight. This plan is also applicable to the Meteorological Satellite (METSAT) except where requirements are identified as EOS-specific. This plan is based on two key factors: a. The EOS/METSAT AMSU-A Instruments are not highly contamination sensitive. b. Potential contamination of other EOS Instruments is a key concern as addressed in Section 9/0 of the Performance Assurance Requirements for EOS/METSAT Integrated Programs AMSU-A Instrument (MR) (NASA Specification S-480-79).

Fay, M.

1998-01-01

113

Modeling elves observed by FORMOSAT-2 satellite  

NASA Astrophysics Data System (ADS)

The ISUAL experiment on the FORMOSAT-2 satellite has confirmed the existence of ionization and Lyman-Birge-Hopfield (LBH) band emissions in elves. In this paper, an in-depth study of the ISUAL recorded elves was carried out. Numerical simulation results of elves based on an electromagnetic finite difference time domain (FDTD) model of the emissions between 185-800 nm and of their spatial-temporal evolution are presented. To account for the effect of atmospheric attenuation, three major attenuation mechanisms: O2, O3, and molecular Rayleigh scattering are considered. Validations of the electromagnetic FDTD model were conducted in three ways: by comparing the calculated and observed photon fluxes in the ISUAL spectrophotometric channels, by directly comparing the simulated and observed morphologies of elves, and by comparing the computed photon counts of the ISUAL Imager based on the derived peak currents for two elve-associated NLDN (National Lightning Detection Network) cloud-to-ground discharges (CGs) with those recorded by the ISUAL Imager. In all three ways, very good agreement was achieved.

Kuo, Cheng-Ling; Chen, A. B.; Lee, Y. J.; Tsai, L. Y.; Chou, R. K.; Hsu, R. R.; Su, H. T.; Lee, L. C.; Cummer, S. A.; Frey, H. U.; Mende, S. B.; Takahashi, Y.; Fukunishi, H.

2007-11-01

114

Satellite observation of atmospheric nuclear gamma radiation.  

PubMed

We present a satellite observation of the spectrum of gamma radiation from the Earth's atmosphere in the energy interval from 300 keV to 8.5 MeV. The data were accumulated by the gamma ray spectrometer on the Solar Maximum Mission over 3 1/2 years, from 1980 to 1983. The excellent statistical accuracy of the data allows 20 atmospheric line features to be identified. The features are superimposed on a continuum background which is modeled using a power law with index -1.16. Many of these features contain a blend of more than one nuclear line. All of these lines (with the exception of the 511-keV annihilation line) are Doppler broadened. Line energies and intensities are consistent with production by secondary neutrons interacting with atmospheric 14N and 16O. Although we find no evidence for other production mechanisms, we cannot rule out significant contributions from direct excitation or spallation by primary cosmic ray protons. The relative intensities of the observed line features are in fair agreement with theoretical models; however, existing models are limited by the availability of neutron cross sections, especially at high energies. The intensity and spectrum of photons at energies below the 511-keV line, in excess of a power law continuum, can be explained by Compton scattering of the annihilation line photons in traversing an average of approximately 21 g cm-2 of atmosphere. PMID:11537397

Letaw, J R; Share, G H; Kinzer, R L; Silberberg, R; Chupp, E L; Forrest, D J; Rieger, E

1989-02-01

115

Satellite observations of temporal terrestrial features  

NASA Technical Reports Server (NTRS)

The application of satellite data to earth resources and environmental studies and the effects of resolution of the photographs and imagery are discussed. The nature of the data acquired by manned space flight and unmanned satellites is described. Specific applications of remotely sensed data for oceanography, hydrology, geography, and geology are examined.

Rabchevsky, G. A.

1972-01-01

116

The investigation of tethered satellite system dynamics  

NASA Technical Reports Server (NTRS)

Tethered satellite system (TSS) dynamics were studied. The dynamic response of the TSS during the entire stationkeeping phase for the first electrodynamic mission was investigated. An out of plane swing amplitude and the tether's bowing were observed. The dynamics of the slack tether was studied and computer code, SLACK2, was improved both in capabilities and computational speed. Speed hazard related to tether breakage or plasma contactor failure was examined. Preliminary values of the potential difference after the failure and of the drop of the electric field along the tether axis have been computed. The update of the satellite rotational dynamics model is initiated.

Lorenzini, E.

1984-01-01

117

Satellite observations of stratospheric carbonyl fluoride  

NASA Astrophysics Data System (ADS)

The vast majority of emissions of fluorine-containing molecules are anthropogenic in nature, e.g. chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and hydrofluorocarbons (HFCs). These molecules slowly degrade in the atmosphere, leading to the formation of HF, COF2, and COClF, which are the main fluorine-containing species in the stratosphere. Ultimately both COF2 and COClF further degrade to form HF, an almost permanent reservoir of stratospheric fluorine due to its extreme stability. Carbonyl fluoride (COF2) is the second-most abundant stratospheric "inorganic" fluorine reservoir, with main sources being the atmospheric degradation of CFC-12 (CCl2F2), HCFC-22 (CHF2Cl), and CFC-113 (CF2ClCFCl2). This work reports the first global distributions of carbonyl fluoride in the Earth's atmosphere using infrared satellite remote-sensing measurements by the Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS), which has been recording atmospheric spectra since 2004, and the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument, which recorded thermal emission atmospheric spectra between 2002 and 2012. The observations reveal a high degree of seasonal and latitudinal variability over the course of a year. These have been compared with the output of SLIMCAT, a state-of-the-art three-dimensional chemical transport model. In general the observations agree well with each other, although MIPAS is biased high by as much as ~30%, and compare well with SLIMCAT. Between January 2004 and September 2010 COF2 grew most rapidly at altitudes above ~25 km in the southern latitudes and at altitudes below ~25 km in the northern latitudes, whereas it declined most rapidly in the tropics. These variations are attributed to changes in stratospheric dynamics over the observation period. The overall COF2 global trend over this period is calculated as 0.85 ± 0.34 (MIPAS), 0.30 ± 0.44 (ACE), and 0.88% year-1 (SLIMCAT).

Harrison, J. J.; Chipperfield, M. P.; Dudhia, A.; Cai, S.; Dhomse, S.; Boone, C. D.; Bernath, P. F.

2014-11-01

118

Satellite observations of stratospheric carbonyl fluoride  

NASA Astrophysics Data System (ADS)

The vast majority of emissions of fluorine-containing molecules are anthropogenic in nature, e.g. chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), and hydrofluorocarbons (HFCs). These molecules slowly degrade in the atmosphere leading to the formation of HF, COF2, and COClF, which are the main fluorine-containing species in the stratosphere. Ultimately both COF2 and COClF further degrade to form HF, an almost permanent reservoir of stratospheric fluorine due to its extreme stability. Carbonyl fluoride (COF2) is the second most abundant stratospheric "inorganic" fluorine reservoir with main sources being the atmospheric degradation of CFC-12 (CCl2F2), HCFC-22 (CHF2Cl), and CFC-113 (CF2ClCFCl2). This work reports the first global distributions of carbonyl fluoride in the Earth's atmosphere using infrared satellite remote-sensing measurements by the Atmospheric Chemistry Experiment Fourier transform spectrometer (ACE-FTS), which has been recording atmospheric spectra since 2004, and the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument, which has recorded thermal emission atmospheric spectra between 2002 and 2012. The observations reveal a high degree of seasonal and latitudinal variability over the course of a year. These have been compared with the output of SLIMCAT, a state-of-the-art three-dimensional chemical transport model. In general the observations agree well with each other and compare well with SLIMCAT, although MIPAS is biased high by as much as ~30%. Between January 2004 and September 2010 COF2 grew most rapidly at altitudes above ~25 km in the southern latitudes and at altitudes below ~25 km in the northern latitudes, whereas it declined most rapidly in the tropics. These variations are attributed to changes in stratospheric dynamics over the observation period. The overall COF2 global trend over this period is calculated as 0.85 ± 0.34 % year-1 (MIPAS), 0.30 ± 0.44% year-1 (ACE), and 0.88% year-1 (SLIMCAT).

Harrison, J. J.; Chipperfield, M. P.; Dudhia, A.; Cai, S.; Dhomse, S.; Boone, C. D.; Bernath, P. F.

2014-07-01

119

Advanced hybrid satellite andAdvanced hybrid satellite and terrestrial system architecture forterrestrial system architecture for  

E-print Network

communications: Satellite links Mobile ad-hoc mesh network Conclusions Future work Main achievements BibliographyAdvanced hybrid satellite andAdvanced hybrid satellite and terrestrial system architecture forterrestrial system architecture for emergency mobile communicationsemergency mobile communications Giuliana

Gesbert, David

120

Aqua: an Earth-Observing Satellite mission to examine water and other climate variables  

Microsoft Academic Search

Aqua is a major satellite mission of the Earth Observing System (EOS), an international program centered at the U.S. National Aeronautics and Space Administration (NASA). The Aqua satellite carries six distinct Earth-observing instruments to measure numerous aspects of Earth's atmosphere, land, oceans, biosphere, and cryosphere, with a concentration on water in the Earth system. Launched on May 4, 2002, the

Claire L. Parkinson

2003-01-01

121

Tethered Satellite System Project Overview  

NASA Technical Reports Server (NTRS)

The Skyhook concept is reviewed and the use of a tethered satellite system (TSS) to enable scientific investigations from the shuttle using a closed loop control system is examined. The tethered satellite system has capabilities for deployment toward or away from Earth, for multiple round trip missions, and for deployment at distances up to 100 KN from the orbiter. The deployer, which consists of an entendable boom, a reel for the tether, and the tether itself, permits deployment and retrieval at a safe distance, allows alignment of the force vector of the tether through the center of gravity of the shuttle, and gives some initial gravity gradient separation to aid in deployment and ultimate retrieval of the tethered satellite. Charts show TSS activities in terms of systems studies, key guidelines, Italian and U.S. responsibilities, user activities, and major science and applications accommodation features. Scientific objectives for TSS-1 and TSS-2 verification missions and the current status of the project are also given.

Laue, J. H.

1985-01-01

122

Monitoring Lake and Reservoir Level: Satellite Observations, Modeling and Prediction  

NASA Astrophysics Data System (ADS)

Satellite measurements of lake and reservoir water levels complement in situ observations by providing stage information for un-gauged basins and by filling data gaps in gauge records. However, different satellite radar altimeter-derived continental water level products may differ significantly owing to choice of satellites and data processing methods. To explore the impacts of these differences, a direct comparison between three different altimeter-based surface water level estimates (USDA/NASA GRLM, LEGOS and ESA-DMU) will be presented and products validated with lake level gauge time series for lakes and reservoirs of a variety of sizes and conditions. The availability of satellite-based rainfall (i.e., TRMM and GPCP) and satellite-based lake/reservoir levels offers exciting opportunities to estimate and monitor the hydrologic properties of the lake systems. Here, a simple water balance model is utilized to relate net freshwater flux on a catchment basin to lake/reservoir level. Focused on tropical lakes and reservoirs it allows a comparison of the flux to altimetric lake level estimates. The combined use of model, satellite-based rainfall, evaporation information and reanalysis products, can be used to output water-level hindcasts and seasonal future forecasts. Such a tool is fundamental for understanding present-day and future variations in lake/reservoir levels and enabling a better understand of climatic variations on inter-annual to inter-decadal time-scales. New model-derived water level estimates of lakes and reservoirs, on regional to global scales, would assist communities with interests in climate studies focusing on extreme events, such as floods and droughts, and be important for water resources management.

Ricko, M.; Birkett, C. M.; Adler, R. F.; Carton, J.

2013-12-01

123

ON THINNING METHODS FOR DATA ASSIMILATION OF SATELLITE OBSERVATIONS  

E-print Network

2B.3 ON THINNING METHODS FOR DATA ASSIMILATION OF SATELLITE OBSERVATIONS T. Ochotta1 C. Gebhardt2 V ABSTRACT Thinning of observational data sets is an essen- tial task in assimilation of satellite data error analysis (EEA). EEA is an adaptive thinning method that iteratively removes observations from

Reiterer, Harald

124

Atmospheric sounding by global navigation satellite system radio occultation: An analysis of the negative refractivity bias using CHAMP observations  

Microsoft Academic Search

Validation studies of current GPS radio occultation experiments using meteorological analyses consistently report on a negative refractivity bias in the lower troposphere. End-to-end simulations including the GPS receiver's signal tracking process suggest that receiver-induced phase deviations contribute to this observed bias. We propose a heuristic retrieval algorithm based on the canonical transform and the sliding spectral technique, which seems less

G. Beyerle; J. Wickert; T. Schmidt; C. Reigber

2004-01-01

125

Satellite data assimilation in global forecast system in India  

NASA Astrophysics Data System (ADS)

Satellite data is very important for model initialization and verification. A large number of satellite observations are currently assimilated into the Numerical Weather Prediction (NWP) systems at the National Centre for Medium Range Weather Forecasting (NCMRWF). Apart from Global meteorological observations from GTS, near-real time satellite observations are received at NCMRWF from other operational centres like ISRO, NOAA/NESDIS, EUMETCAST, etc. Recently India has become member of Asia-Pacific Regional ATOVS Retransmission Service (APRARS) for faster access to high resolution global satellite data useful for high resolution regional models. Indian HRPT at Chennai covers the APRARS data gap region over South East Asia. A robust data monitoring system has been implemented at NCMRWF to assess the quantity and quality of the data as well as the satellite sensor strength, before getting assimilated in the models. Validation of new satellite observations, especially from Indian satellites are being carried out against insitu observations and similar space borne platforms. After establishing the quality of the data, Observation System Experiments (OSEs) are being conducted to study their impact in the assimilation and forecast systems. OSEs have been carried out with the Oceansat-2 scatterometer winds and radiance data from Megha-Tropiques SAPHIR sensor. Daily rainfall analysis dataset is being generated by merging satellite estimates and in-situ observations. ASCAT soil wetness measurements from METOP satellite is being assimilated into the global model. Land surface parameters (LuLc and albedo) retrieved from Indian satellites are being explored for its possible usage in the global and regional models. OLR from Indian satellites are used for validating model outputs. This paper reviews the efforts made at NCMRWF in (i) assimilating the data from Indian/International satellites and (ii) generating useful products from the satellite data.

Basu, Swati

2014-11-01

126

Introduction satellite observations of atmospheric constitents have  

E-print Network

and can be oxidised within airborne water droplets, producing sulphuric acid. This acidic pollution can suitable for monitoring anthropogenic pollution aspects. Tropospheric nitrogen dioxide Satellite light from the Earth's atmosphere with a reference spectrum, the column density of nitrogen dioxide

Haak, Hein

127

Operational Applications of Satellite Snowcover Observations  

NASA Technical Reports Server (NTRS)

LANDSAT and NOAA satellites data were used to study snow depth. These snow measurements were used to help forecast runoff and flooding. Many areas of California, Arizona, Colorado, and Wyoming were emphasized.

Rango, A. (editor)

1975-01-01

128

Evaluating NOx Emissions Using Satellite Observations  

NASA Astrophysics Data System (ADS)

Atmospheric NO2 columns retrieved from satellites can provide a useful top-down assessment of bottom-up NOx emissions inventories. We present three case studies of an approach to evaluate NOx emissions at a sector level by comparing satellite retrievals to regional chemical-transport model calculations of NO2 columns. In the first example, the atmospheric impact of implementing NOx controls at eastern US power plants is demonstrated. In the second study, we use NOx monitors at western US power plants to calibrate our satellite-model comparisons. We then apply our approach to evaluate bottom-up estimates of NOx emissions from western US cities. In the third example, we validate our satellite-model approach using in-situ aircraft measurements and assess NOx emissions from power plants, cities, industrial facilities, and ports in eastern Texas. We conclude with some general insights on the usefulness of this approach and suggestions for future areas of research.

Frost, G. J.; Kim, S.; Brioude, J.; McKeen, S. A.; Trainer, M.; Heckel, A.; Hilboll, A.; Richter, A.; Burrows, J. P.; Gleason, J. F.; Boersma, K. F.; Hsie, E.; Lee, S.; Angevine, W. M.; Granier, C.; Peischl, J.; Ryerson, T. B.; Fehsenfeld, F. C.

2012-12-01

129

Propagation Effects Handbook for Satellite Systems Design  

E-print Network

and how they impact satellite communications system design and performance. The First EditionPropagation Effects Handbook for Satellite Systems Design Fifth Edition Section 1 Background Dr for Satellite Systems Design continues the long process of a continuing NASA commitment to provide

Pulfrey, David L.

130

The Chinese FY-1 Meteorological Satellite Application in Observation on Oceanic Environment  

NASA Astrophysics Data System (ADS)

meteorological satellite is stated in this paper. exploration of the ocean resources has been a very important question of global strategy in the world. The exploration of the ocean resources includes following items: Making full use of oceanic resources and space, protecting oceanic environment. to observe the ocean is by using of satellite. In 1978, US successfully launched the first ocean observation satellite in the world --- Sea Satellite. It develops ancient oceanography in to advanced space-oceanography. FY-1 B and FY- IC respectively. High quality data were acquired at home and abroad. FY-1 is Chinese meteorological satellite, but with 0.43 ~ 0.48 ?m ,0.48 ~ 0.53 ?m and 0.53 ~ 0.58 ?m three ocean color channels, actually it is a multipurpose remote sensing satellite of meteorology and oceanography. FY-1 satellite's capability of observation on ocean partly, thus the application field is expanded and the value is increased. With the addition of oceanic channels on FY-1, the design of the satellite is changed from the original with meteorological observation as its main purpose into remote sensing satellite possessing capability of observing meteorology and ocean as well. Thus, the social and economic benefit of FY-1 is increased. the social and economic benefit of the development of the satellite is the key technique in the system design of the satellite. technically feasible but also save the funds in researching and manufacturing of the satellite, quicken the tempo of researching and manufacturing satellite. the scanning radiometer for FY-1 is conducted an aviation experiment over Chinese ocean. This experiment was of vital importance to the addition of oceanic observation channel on FY-1. FY-1 oceanic channels design to be correct. detecting ocean color. This is the unique character of Chinese FY-1 meteorological satellite. meteorological remote sensing channel on FY-1 to form detecting capability of three visible channels: red, yellow and blue spectrum bands. Thus FY-1 satellite can be used for observation on ocean color experiment. This experiment is successful, a lot of data were acquired. Good application results were obtained in the field of oceanic science research. Therefore, it makes FY-1 a remote sensing satellite used for observation on meteorology and ocean. This is the unique character of Chinese FY-1 meteorological satellite, it is widely noticed all over the world. Chinese meteorological satellite has been realized the aim of using one satellite for multipurpose applications and brought more and more social and economic benefit. oceanic channel in Chinese meteorological satellites is also foreseen to expand the application field in Chinese meteorological satellites. Key Word : Meteorological Satellite Oceanic Remote Sensing

Weimin, S.

131

A review of mobile satellite communication systems  

NASA Astrophysics Data System (ADS)

This article describes mobile satellite systems in the planning or development stage such as MSAT, AMSC and Geostar and mobile satellite communication experiments such as PRODAT. Studies on the system such as T-SAT are also reviewed. In addition, Japanese ETS-V and ETS-VI are described. The development of mobile-satellite communication systems is promoted along with those of communication and satellite technologies.

Kondo, Kimio

1990-03-01

132

Satellite operations support expert system  

NASA Technical Reports Server (NTRS)

The Satellite Operations Support Expert System is an effort to identify aspects of satellite ground support activity which could profitably be automated with artificial intelligence (AI) and to develop a feasibility demonstration for the automation of one such area. The hydrazine propulsion subsystems (HPS) of the International Sun Earth Explorer (ISEE) and the International Ultraviolet Explorer (IUS) were used as applications domains. A demonstration fault handling system was built. The system was written in Franz Lisp and is currently hosted on a VAX 11/750-11/780 family machine. The system allows the user to select which HPS (either from ISEE or IUE) is used. Then the user chooses the fault desired for the run. The demonstration system generates telemetry corresponding to the particular fault. The completely separate fault handling module then uses this telemetry to determine what and where the fault is and how to work around it. Graphics are used to depict the structure of the HPS, and the telemetry values displayed on the screen are continually updated. The capabilities of this system and its development cycle are described.

1985-01-01

133

Astrometry in the Uranian system of satellites  

NASA Astrophysics Data System (ADS)

The predicted occultation between the satellites Miranda(UV) and Oberon(UIV) was observed on July 30, 2007 using SpeX/IRTF system and CODAM-Paris Observatory facility. Data analysis reveals that the predicted magnitude drop for this phenomenon was overestimated and we establish an upper limit of 0m.05 for the phenomenon, perhaps due to a non-lambertian limb scattering. The astrometry obtained from this run reveals good agreement with the LA06 numerical model.

Birlan, Mirel; Nedelcu, Dan Alin

2008-09-01

134

Studies of the major planet satellite systems  

NASA Technical Reports Server (NTRS)

A summary is presented of the available data on the satellites of the major planets, including the currently most plausible models for several observed phenomena, for the planning of spacecraft missions to these objects. Some of the important questions likely to be solved by flyby and/or orbital missions to the giant planets are detailed, the importance of these studies to our understanding of the solar system as a whole is indicated.

Frey, H.; Lowman, P. D.

1974-01-01

135

EUMETSAT Meteorological Satellite conference, Cordoba, 21/9/2010 observation  

E-print Network

EUMETSAT Meteorological Satellite conference, Cordoba, 21/9/2010 ADM-Aeolus wind observation from Meteorological Satellite conference, Cordoba, 21/9/2010 Need for space winds · Wind determines small and sparse 3D meteorological observations are present; reduce errors over the ocean · Transport

Stoffelen, Ad

136

Satellite freeze forecast system: Executive summary  

NASA Technical Reports Server (NTRS)

A satellite-based temperature monitoring and prediction system consisting of a computer controlled acquisition, processing, and display system and the ten automated weather stations called by that computer was developed and transferred to the national weather service. This satellite freeze forecasting system (SFFS) acquires satellite data from either one of two sources, surface data from 10 sites, displays the observed data in the form of color-coded thermal maps and in tables of automated weather station temperatures, computes predicted thermal maps when requested and displays such maps either automatically or manually, archives the data acquired, and makes comparisons with historical data. Except for the last function, SFFS handles these tasks in a highly automated fashion if the user so directs. The predicted thermal maps are the result of two models, one a physical energy budget of the soil and atmosphere interface and the other a statistical relationship between the sites at which the physical model predicts temperatures and each of the pixels of the satellite thermal map.

Martsolf, J. D. (principal investigator)

1983-01-01

137

Recent La Plata basin drought conditions observed by satellite gravimetry  

E-print Network

The Gravity Recovery and Climate Experiment (GRACE) provides quantitative measures of terrestrial water storage (TWS) change. GRACE data show a significant decrease in TWS in the lower (southern) La Plata river basin of South America over the period 2002-2009, consistent with recognized drought conditions in the region. GRACE data reveal a detailed picture of temporal and spatial evolution of this severe drought event, which suggests that the drought began in lower La Plata in around austral spring 2008 and then spread to the entire La Plata basin and peaked in austral fall 2009. During the peak, GRACE data show an average TWS deficit of ~12 cm (equivalent water layer thickness) below the 7 year mean, in a broad region in lower La Plata. GRACE measurements are consistent with accumulated precipitation data from satellite remote sensing and with vegetation index changes derived from Terra satellite observations. The Global Land Data Assimilation System model captures the drought event but underestimates its in...

Chen, J L; Tapley, B D; Longuevergne, L; Yang, Z L; Scanlon, B R; 10.1029/2010JD014689

2010-01-01

138

Tethered Satellite System Contingency Investigation Board  

NASA Technical Reports Server (NTRS)

The Tethered Satellite System (TSS-1) was launched aboard the Space Shuttle Atlantis (STS-46) on July 31, 1992. During the attempted on-orbit operations, the Tethered Satellite System failed to deploy successfully beyond 256 meters. The satellite was retrieved successfully and was returned on August 6, 1992. The National Aeronautics and Space Administration (NASA) Associate Administrator for Space Flight formed the Tethered Satellite System (TSS-1) Contingency Investigation Board on August 12, 1992. The TSS-1 Contingency Investigation Board was asked to review the anomalies which occurred, to determine the probable cause, and to recommend corrective measures to prevent recurrence. The board was supported by the TSS Systems Working group as identified in MSFC-TSS-11-90, 'Tethered Satellite System (TSS) Contingency Plan'. The board identified five anomalies for investigation: initial failure to retract the U2 umbilical; initial failure to flyaway; unplanned tether deployment stop at 179 meters; unplanned tether deployment stop at 256 meters; and failure to move tether in either direction at 224 meters. Initial observations of the returned flight hardware revealed evidence of mechanical interference by a bolt with the level wind mechanism travel as well as a helical shaped wrap of tether which indicated that the tether had been unwound from the reel beyond the travel by the level wind mechanism. Examination of the detailed mission events from flight data and mission logs related to the initial failure to flyaway and the failure to move in either direction at 224 meters, together with known preflight concerns regarding slack tether, focused the assessment of these anomalies on the upper tether control mechanism. After the second meeting, the board requested the working group to complete and validate a detailed integrated mission sequence to focus the fault tree analysis on a stuck U2 umbilical, level wind mechanical interference, and slack tether in upper tether control mechanism and to prepare a detailed plan for hardware inspection, test, and analysis including any appropriate hardware disassembly.

1992-01-01

139

Outline of the survey on the development of earth observation satellites  

NASA Technical Reports Server (NTRS)

An independent earth observation system with land and sea satellites to be developed by Japan is described. Visible and infrared radiometers, microwave radiometers, microwave scattermeters, synthetic aperture radar, and laser sensors are among the instrumentation discussed. Triaxial attitude control, basic technology common to sea and land observation satellites as well as land data analytical technology developed for U.S. LANDSAT data are reviewed.

1977-01-01

140

Co-ordination of satellite and data programs: The committee on earth observation satellites' approach  

NASA Astrophysics Data System (ADS)

Every year, an average of eight new civilian remote sensing satellite missions are launched. Cumulatively, over 250 such missions, each with a cost equivalent in current value to between US 100 million to US 1000 million, have been sponsored by space agencies in perhaps two dozen countries. These missions produce data and information products which are vital for informed decision making all over the world, on matters relating to natural resource exploitation, health and safety, sustainable national development, infrastructure planning, and a host of other applications. By contributing to better scientific understanding of global changes in the atmosphere, land surface, oceans and ice caps, these silently orbiting sentinels in the sky make it possible for governments and industries to make wiser environmental policy decisions and support the economic development needs of humanity. The international Committee on Earth Observation Satellites (CEOS) is the premier world body for co-ordinating and planning civilian satellite missions for Earth observation. Through its technical working groups and special task teams, it endeavours to: • maximise the international benefits from Earth observation satellites; and • harmonise practice in calibration, validation, data management and information systems for Earth observation. CEOS encompasses not only space agencies (data providers), but also the great international scientific and operational programs which rely on Earth science data from space. The user organisations affiliated with CEOS, together with the mission operators, attempt to reconcile user needs with the complex set of considerations — including national interests, cost, schedule — which affect the undertaking of space missions. Without such an internationally co-ordinated consensual approach, there is a much greater risk of waste through duplication, and of missed opportunity, or through the absence of measurements of some vital physical or biological parameter by space borne sensors. Mechanisms used by CEOS to carry out these tasks are built upon consensus and understanding, as well as on technology transfer between countries. An area of recent heightened endeavour in CEOS has been to determine and address the special needs of developing countries in respect of Earth observation data. In the next several years, a new wave of Earth observation will break, as the private sector, revitalised with decommissioned military technology, brings exciting new capabilities to international remote sensing. With rapidly burgeoning markets in spatial information or geomatics, as well as the continuing thirst of science programs for spatial information, there is a challenge upon the international space community to reassess continually, the most expedient and socially constructive means of making available in a fair and open way, geographically-reference information obtained with space observation systems.

Embleton, B. J. J.; Kingwell, J.

1997-01-01

141

Satellite voice broadcast system study, volume 2  

NASA Technical Reports Server (NTRS)

This study investigates the feasibility of providing Voice of America (VOA) broadcasts by satellite relay, rather than via terrestrial relay stations. Satellite voice broadcast systems are described for three different frequency bands: HF (26 MHz), VHF (68 MHz), and L-band (1.5 GHz). The geographical areas of interest at HF and L-band include all major land masses worldwide with the exception of the U.S., Canada, and Australia. Geostationary satellite configurations are considered for both frequency bands. In addition, a system of subsynchronous, circular satellites with an orbit period of 8 hours is developed for the HF band. VHF broadcasts, which are confined to the Soviet Union, are provied by a system of Molniya satellites. Satellites intended for HF or VHF broadcastinbg are extremely large and heavy. Satellite designs presented here are limited in size and weight to the capability of the STS/Centaur launch vehicle combination. Even so, at HF it would take 47 geostationary satellites or 20 satellites in 8-hour orbits to fully satisfy the voice-channel requirements of the broadcast schedule provided by VOA. On the other hand, three Molniya satellites suffice for the geographically restricted schedule at VHF. At L-band, only four geostationary satellites are needed to meet the requirements of the complete broadcast schedule. Moreover, these satellites are comparable in size and weight to current satellites designed for direct broadcast of video program material.

Horstein, M.

1985-01-01

142

Satellite Observed Changes in the Arctic  

NASA Technical Reports Server (NTRS)

The Arctic is currently considered an area in transformation. Glaciers have been retreating, permafrost has been diminishing, snow covered areas have been decreasing, and sea ice and ice sheets have been thinning. This paper provides an overview of the unique role that satellite sensors have contributed in the detection of changes in the Arctic and demonstrates that many of the changes are not just local but a pan-Arctic phenomenon. Changes from the upper atmosphere to the surface are discussed and it is apparent that the magnitude of the trends tends to vary from region to region and from season to season. Previous reports of a warming Arctic and a retreating perennial ice cover have also been updated, and results show that changes are ongoing. Feedback effects that can lead to amplification of the signals and the role of satellite data in enhancing global circulation models are also discussed.

Comiso, Josefino C.; Parkinson, Claire L.

2004-01-01

143

The Nimbus satellites - Pioneering earth observers  

SciTech Connect

The many scientific achievements of the Nimbus series of seven satellites for low-altitude atmospheric research and global weather surveillance are reviewed. The series provides information on fishery resources, weather modeling, atmospheric pollution monitoring, earth's radiation budget, ozone monitoring, ocean dynamics, and the effects of cloudiness. Data produced by the forty-eight instruments and sensors flown on the satellites are applied in the fields of oceanography, hydrology, geology, geomorphology, geography, cartography, agriculture and meteorology. The instruments include the Coastal Zone Color Scanner (which depicts phytoplankton concentrations in coastal areas), the Scanning Multichannel Microwave Radiometer (which measures sea-surface temperatures and sea-surface wind-speed), and the Total Ozone Mapping Spectrometer (which provides information on total amounts of ozone in the earth's atmosphere).

White, C. (NASA, Goddard Space Flight Center, Greenbelt, MD (USA))

1990-11-01

144

The Nimbus satellites - Pioneering earth observers  

NASA Technical Reports Server (NTRS)

The many scientific achievements of the Nimbus series of seven satellites for low-altitude atmospheric research and global weather surveillance are reviewed. The series provides information on fishery resources, weather modeling, atmospheric pollution monitoring, earth's radiation budget, ozone monitoring, ocean dynamics, and the effects of cloudiness. Data produced by the forty-eight instruments and sensors flown on the satellites are applied in the fields of oceanography, hydrology, geology, geomorphology, geography, cartography, agriculture and meteorology. The instruments include the Coastal Zone Color Scanner (which depicts phytoplankton concentrations in coastal areas), the Scanning Multichannel Microwave Radiometer (which measures sea-surface temperatures and sea-surface wind-speed), and the Total Ozone Mapping Spectrometer (which provides information on total amounts of ozone in the earth's atmosphere).

White, Carolynne

1990-01-01

145

Astrographic observations of the major Uranian satellites from Voyager 2  

NASA Technical Reports Server (NTRS)

This article provides the reduced astrographic observations of the major Uranian satellites derived from star-satellite imaging data acquired by the Voyager 2 spacecraft. The data set contains 445 sets of spacecraft-centered right ascension and declination observations and includes all of the observations used in Voyager encounter operations. The conversion process from imaging to astrographic observations was identical to that used for the Neptunian satellites (Jacobson 1991). The effect of using the astrographic rather than imaging form in ephemeris improvement is evaluated.

Jacobson, R. A.

1992-01-01

146

Astrographic observations of the major Uranian satellites from Voyager 2  

NASA Astrophysics Data System (ADS)

This article provides the reduced astrographic observations of the major Uranian satellites derived from star-satellite imaging data acquired by the Voyager 2 spacecraft. The data set contains 445 sets of spacecraft-centered right ascension and declination observations and includes all of the observations used in Voyager encounter operations. The conversion process from imaging to astrographic observations was identical to that used for the Neptunian satellites (Jacobson 1991). The effect of using the astrographic rather than imaging form in ephemeris improvement is evaluated.

Jacobson, R. A.

1992-12-01

147

Perl Tools for Automating Satellite Ground Systems  

NASA Technical Reports Server (NTRS)

The freeware scripting language Pert offers many opportunities for automating satellite ground systems for new satellites as well as older, in situ systems. This paper describes a toolkit that has evolved from of the experiences gained by using Pert to automate the ground system for the Compton Gamma Ray Observatory (CGRO) and for automating some of the elements in the Earth Observing System Data and Operations System (EDOS) ground system at Goddard Space Flight Center (GSFC). CGRO is an older ground system that was forced to automate because of fund cuts. Three 8 hour shifts were cut back to one 8 hour shift, 7 days per week. EDOS supports a new mission called Terra, launched December 1999 that requires distribution and tracking of mission-critical reports throughout the world. Both of these ground systems use Pert scripts to process data and display it on the Internet as well as scripts to coordinate many of the other systems that make these ground systems work as a coherent whole. Another task called Automated Multimodal Trend Analysis System (AMTAS) is looking at technology for isolation and recovery of spacecraft problems. This effort has led to prototypes that seek to evaluate various tools and technology that meet at least some of the AMTAS goals. The tools, experiences, and lessons learned by implementing these systems are described here.

McLean, David; Haar, Therese; McDonald, James

2000-01-01

148

The Aerospace Corporation 2009 Communication Satellite Systems  

E-print Network

© The Aerospace Corporation 2009 Communication Satellite Systems Trends and Network Aspects Paul://www.aero.org/ Lee Center, Caltech 13 April 2009 #12;22 Communication Satellites · Brief History by Decade · Trends: ­ Communication Satellites, fifth edition, by D. Martin, P. Anderson, L. Bartamian, Aerospace / AIAA Press, 2006

Low, Steven H.

149

Developing a global aeronautical satellite system  

NASA Technical Reports Server (NTRS)

Arinc, an airline industry-owned and operated company in the United States, has taken steps toward establishing a global aeronautical satellite communications system. Plans call for initiation of a thin-route data operation in 1989, upgrading to establish voice communications via shared spot-beam transponders carried on other satellites, and deploying a worldwide network using dedicated satellites by 1994.

Dement, Donald K.

1988-01-01

150

Observations of the Climate System  

NASA Technical Reports Server (NTRS)

Observations of the climate system are critical for model validation and initialization, and also for monitoring in case of "surprises." Presently. we are still benefiting from data provided by the international fleet of Earth Observing satellites launched from the late 1990's onwards as well as from the longer-term record provided hy the operational meteorological satellites. However, we could be facing some data gaps in the near term in some critical areas. In situ measurements continue to be vital and, while they may be augmented hy future satellite measurements, will continue to be irreplaceable.

Sellers, Piers J.

2012-01-01

151

Assessment of Global Annual Atmospheric Energy Balance from Satellite Observations  

NASA Technical Reports Server (NTRS)

Global atmospheric energy balance is one of the fundamental processes for the earth's climate system. This study uses currently available satellite data sets of radiative energy at the top of atmosphere (TOA) and surface and latent and sensible heat over oceans for the year 2000 to assess the global annual energy budget. Over land, surface radiation data are used to constrain assimilated results and to force the radiation, turbulent heat, and heat storage into balance due to a lack of observation-based turbulent heat flux estimations. Global annual means of the TOA net radiation obtained from both direct measurements and calculations are close to zero. The net radiative energy fluxes into the surface and the surface latent heat transported into the atmosphere are about 113 and 86 Watts per square meter, respectively. The estimated atmospheric and surface heat imbalances are about -8 9 Watts per square meter, values that are within the uncertainties of surface radiation and sea surface turbulent flux estimates and likely systematic biases in the analyzed observations. The potential significant additional absorption of solar radiation within the atmosphere suggested by previous studies does not appear to be required to balance the energy budget the spurious heat imbalances in the current data are much smaller (about half) than those obtained previously and debated at about a decade ago. Progress in surface radiation and oceanic turbulent heat flux estimations from satellite measurements significantly reduces the bias errors in the observed global energy budgets of the climate system.

Lin, Bing; Stackhouse, Paul; Minnis, Patrick; Wielicki, Bruce A.; Hu, Yongxiang; Sun, Wenbo; Fan, Tai-Fang (Alice); Hinkelman, Laura

2008-01-01

152

Issues in satellite personal communication systems  

Microsoft Academic Search

In the paper various issues in personal satellite communications are addressed. Basic geostationary and non?geostationary\\u000a satellite constellations are considered. The narrowband and wideband characterization of the mobile satellite channel and\\u000a related system implications are discussed. Satellite diversity is presented as a measure to overcome signal shadowing. The\\u000a capacity of TDMA and CDMA multiple access is estimated, taking into account co?channel

Erich Lutz

1998-01-01

153

Description of the AMSC mobile satellite system  

NASA Astrophysics Data System (ADS)

The American Mobile Satellite Corporation will provide a full range of mobile satellite services through a mobile satellite system dedicated to mobile use in the United States. This paper provides a summary of the system architecture with descriptions of each of the major system elements. The elements are the space segment, network control system, mobile earth terminals and feeder-link earth stations. The general transmission plan is also described.

Garner, W. B.

154

Land surface albedo based on GOES geostationary satellite observations  

NASA Astrophysics Data System (ADS)

Land surface albedo is the fraction of incoming solar radiation reflected by the land surface, and therefore can be a sensitive indicator of environmental changes. To this end, surface albedo is identified as an Essential Climate Variable (ECV) by the Global Climate Observing System (GCOS). NOAA's National Climatic Data Center (NCDC) recently adapted the Geostationary Surface Albedo (GSA; Lattanzio and Govaerts, 2010) algorithm for use with GOES data in support of a global albedo initiative led by the Sustained, Coordinated Processing of Environmental Satellite Data for Climate Monitoring (SCOPE-CM). SCOPE-CM helps coordinate ECV production responding to GCOS, WMO, and CEOS goals. The GSA algorithm was developed jointly by EUMETSAT and Joint Research Centre (JRC) using a method proposed by Pinty et al. (2000) to determine surface albedo using day-time, cloud-free geostationary observations from a single visible band. For the GOES implementation, raw GOES observations are calibrated using International Satellite Cloud Climatology Project (ISCCP) coefficients. Surface angular anisotropy is determined through the inversion of the GSA radiative transfer model using multiple geostationary images collected over a day under different illumination conditions. The inversion process requires ancillary total column ozone and water vapor values, which are acquired from the 20th Century Reanalysis V2 data set. The GSA algorithm produces a 10-day composite surface albedo map. This product is initially being developed for the years 2000-2003. Product quality is being assessed through comparisons with MODIS products as well as ground-based measurements. NCDC is producing albedo products from both GOES-E (75°W) and GOES-W (135°W). These are being merged with like products from EUMETSAT based on METEOSAT (0° and 63°E) and from JMA based on the Geostationary Meteorological Satellite System (140°E). In the near future, NOAA's Climate Data Record Program will provide the albedo product over the entire GOES period of record (1978-present).

Matthews, J. L.; Lattanzio, A.; Hankins, B.; Knapp, K.; Privette, J. L.

2012-12-01

155

Rapid disintegration of Alpine glaciers observed with satellite data  

Microsoft Academic Search

Analyses of multispectral satellite data indicate accelerated glacier decline around the globe since the 1980s. By using digitized glacier outlines inferred from the 1973 inventory and Landsat Thematic Mapper (TM) satellite data from 1985 to 1999, we obtained area changes of about 930 Alpine glaciers. The 18% area reduction as observed for the period 1985 to 1999 (-1.3% a-1) corresponds

Frank Paul; Andreas Kääb; Max Maisch; Tobias Kellenberger; Wilfried Haeberli

2004-01-01

156

Rapid disintegration of Alpine glaciers observed with satellite data  

Microsoft Academic Search

Analyses of multispectral satellite data indicate accelerated glacier decline around the globe since the 1980s. By using digitized glacier outlines inferred from the 1973 inventory and Landsat Thematic Mapper (TM) satellite data from 1985 to 1999, we obtained area changes of about 930 Alpine glaciers. The 18% area reduction as observed for the period 1985 to 1999 (?1.3% a?1) corresponds

Frank Paul; Andreas Kääb; Max Maisch; Tobias Kellenberger; Wilfried Haeberli

2004-01-01

157

The Earth Observing System  

NASA Technical Reports Server (NTRS)

The restructuring of the NASA Earth Observing System (EOS), designed to provide comprehensive long term observations from space of changes occurring on the Earth from natural and human causes in order to have a sound scientific basis for policy decisions on protection of the future, is reported. In response to several factors, the original program approved in the fiscal year 1991 budget was restructured and somewhat reduced in scope. The resulting program uses three different sized launch vehicles to put six different spacecraft in orbit in the first phase, followed by two replacement launches for each of five of the six satellites to maintain a long term observing capability to meet the needs of global climate change research and other science objectives. The EOS system, including the space observatories, the data and information system, and the interdisciplinary global change research effort, are approved and proceeding. Elements of EOS are already in place, such as the research investigations and initial data system capabilities. The flights of precursor satellite and Shuttle missions, the ongoing data analysis, and the evolutionary enhancements to the integrated Earth science data management capabilities are all important building blocks to the full EOS program.

Shaffer, Lisa Robock

1992-01-01

158

Assimilation of GOES satellite-based convective initiation and cloud growth observations into the Rapid Refresh and HRRR systems to improve aviation forecast guidance  

NASA Astrophysics Data System (ADS)

Latent heating profiles derived from GOES satellite-based cloud-top cooling rates are being assimilated into a retrospective version of the Rapid Refresh system (RAP) being run at the Global Systems Division. Assimilation of these data may help reduce the time lag for convection initiation (CI) in both the RAP model forecasts and in 3-km High Resolution Rapid Refresh (HRRR) model runs that are initialized off of the RAP model grids. These data may also improve both the location and organization of developing convective storm clusters, especially in the nested HRRR runs. These types of improvements are critical for providing better convective storm guidance around busy hub airports and aviation corridor routes, especially in the highly congested Ohio Valley - Northeast - Mid-Atlantic region. Additional work is focusing on assimilating GOES-R CI algorithm cloud-top cooling-based latent heating profiles directly into the HRRR model. Because of the small-scale nature of the convective phenomena depicted in the cloud-top cooling rate data (on the order of 1-4 km scale), direct assimilation of these data in the HRRR may be more effective than assimilation in the RAP. The RAP is an hourly assimilation system developed at NOAA/ESRL and was implemented at NCEP as a NOAA operational model in May 2012. The 3-km HRRR runs hourly out to 15 hours as a nest within the ESRL real-time experimental RAP. The RAP and HRRR both use the WRF ARW model core, and the Gridpoint Statistical Interpolation (GSI) is used within an hourly cycle to assimilate a wide variety of observations (including radar data) to initialize the RAP. Within this modeling framework, the cloud-top cooling rate-based latent heating profiles are applied as prescribed heating during the diabatic forward model integration part of the RAP digital filter initialization (DFI). No digital filtering is applied on the 3-km HRRR grid, but similar forward model integration with prescribed heating is used to assimilate information from radar reflectivity, lightning flash density and the satellite based cloud-top cooling rate data. In the current HRRR configuration, 4 15-min cycles of latent heating are applied during a pre-forecast hour of integration. This is followed by a final application of GSI at 3-km to fit the latest conventional observation data. At the conference, results from a 5-day retrospective period (July 5-10, 2012) will be shown, focusing on assessment of data impact for both the RAP and HRRR, as well as the sensitivity to various assimilation parameters, including assumed heating strength. Emphasis will be given to documenting the forecast impacts for aviation applications in the Eastern U.S.

Mecikalski, John; Smith, Tracy; Weygandt, Stephen

2014-05-01

159

Angular anisotropy of satellite observations of land surface temperature  

NASA Astrophysics Data System (ADS)

Satellite-based time series of land surface temperature (LST) have the potential to be an important tool to diagnose climate changes of the past several decades. Production of such a time series requires addressing several issues with using asynchronous satellite observations, including the diurnal cycle, clouds, and angular anisotropy. Here we evaluate the angular anisotropy of LST using one full year of simultaneous observations by two Geostationary Operational Environment Satellites, GOES-EAST and GOES-WEST, at the locations of five surface radiation (SURFRAD) stations. We develop a technique to convert directionally observed LST into direction-independent equivalent physical temperature of the land surface. The anisotropy model consists of an isotropic kernel, an emissivity kernel (LST dependence on viewing angle), and a solar kernel (effect of directional inhomogeneity of observed temperature). Application of this model reduces differences of LST observed from two satellites and between the satellites and surface ground truth - SURFRAD station observed LST. The techniques of angular adjustment and temporal interpolation of satellite observed LST open a path for blending together historical, current, and future observations of many geostationary and polar orbiters into a homogeneous multi-decadal data set for climate change research.

Vinnikov, Konstantin Y.; Yu, Yunyue; Goldberg, Mitchell D.; Tarpley, Dan; Romanov, Peter; Laszlo, Istvan; Chen, Ming

2012-12-01

160

Observations of orbital debris and satellites in Slovak Republic  

NASA Astrophysics Data System (ADS)

There are many accidental optically tracked artificial objects during observations at Astronom-ical and Geophysical Observatory FMPI CU, Modra, Slovak Republic (AGO). Those objects are usually orbital debris or satellites. A tool to identify such a type of objects was necessary to create. Our software is called SatEph and is used to identify tracked artificial objects and to compute their orbital elements. SatEph is based on analytic propagation model SGP4 and TLE data. Program is still under development and in the near future it will be a part of software for automated search telescope for small near Earth asteroids at AGO. We present orbital debris observation simulation for the new optical searching system. Unlike other aster-oids searching systems (Catalina Sky Survey, LINEAR, Spacewatch etc.) our system should be capable to detect small asteroids in close vicinity of the Earth (smaller then Lunar distance) with high angular speed. The limiting magnitude of observable objects is about +16 magnitude and the pixel scale is 4,6 arcsec/px. This allows us to detect man made objects as well. We studied how many satellites and orbital debris with known orbital elements are able to track per given observing night. We also studied frequency detection of tracked object during one night. The searching system field of view will be 4.4 x 4.4 square degrees and the system will search more then 2000 square degrees per night. Exposure time for every single CCD shot is set to 30 seconds. We found out, there is possible to track from 250 to 450 objects (mostly with geosynchronous orbits) per one night in dependence on given day of the year. More then 200 objects have at least 3 astrometric positions per one night, which can be useful for orbit determination process. The tracked objects are mostly satellites and rocket bodies, which have different orbits, from low Earth orbit to geosynchronous Earth orbit. Data of orbital debris astrometric positions will be offered for national space agencies and used for our own orbit determination. Those data could be useful for orbital elements updating of catalogue, or non catalogue artificial objects.

Silha, Jiri; Toth, Juraj

161

Characterizing user requirements for future land observing satellites  

NASA Technical Reports Server (NTRS)

The objective procedure was developed for identifying probable sensor and mission characteristics for an operational satellite land observing system. Requirements were systematically compiled, quantified and scored by type of use, from surveys of federal, state, local and private communities. Incremental percent increases in expected value of data were estimated for critical system improvements. Comparisons with costs permitted selection of a probable sensor system, from a set of 11 options, with the following characteristics: 30 meter spatial resolution in 5 bands and 15 meters in 1 band, spectral bands nominally at Thematic Mapper (TM) bands 1 through 6 positions, and 2 day data turn around for receipt of imagery. Improvements are suggested for both the form of questions and the procedures for analysis of future surveys in order to provide a more quantitatively precise definition of sensor and mission requirements.

Barker, J. L.; Cressy, P. J.; Schnetzler, C. C.; Salomonson, V. V.

1981-01-01

162

Precise station positions from VLBI observations to satellites: a simulation study  

NASA Astrophysics Data System (ADS)

Very long baseline interferometry (VLBI) tracking of satellites is a topic of increasing interest for the establishment of space ties. This shall strengthen the connection of the various space geodetic techniques that contribute to the International Terrestrial Reference Frame. The concept of observing near-Earth satellites demands research on possible observing strategies. In this paper, we introduce this concept and discuss its possible benefits for improving future realizations of the International Terrestrial Reference System. Using simulated observations, we develop possible observing strategies that allow the determination of radio telescope positions in the satellite system on Earth with accuracies of a few millimeters up to 1-2 cm for weekly station coordinates. This is shown for satellites with orbital heights between 2,000 and 6,000 km, observed by dense regional as well as by global VLBI-networks. The number of observations, as mainly determined by the satellite orbit and the observation interval, is identified as the most critical parameter that affects the expected accuracies. For observations of global positioning system satellites, we propose the combination with classical VLBI to radio sources or a multi-satellite strategy. Both approaches allow station position repeatabilities of a few millimeters for weekly solutions.

Plank, Lucia; Böhm, Johannes; Schuh, Harald

2014-07-01

163

The Use of a Parallel Data Processing and Error Analysis System (DPEAS) for the Observational Exploration of Complex Multi-Satellite Non-Gaussian Data Assimilation Algorithms  

NASA Astrophysics Data System (ADS)

The CSU/NOAA Data Processing and Error Analysis System (DPEAS) was created to merge, or blend, multiple satellite and model data sets within a single consistent framework. DPEAS is designed to be used at both research and operational facilities to facilitate Research-to-Operations technology transfers. The system supports massive parallelization via grid computing technologies, and hosts data fusion techniques for transference to 24/7 operations in a low cost computational environment. In this work, we highlight the data assimilation and data fusion methodologies of the DPEAS framework that facilitates new and complex multi-satellite non-Gaussian data assimilation algorithm developments. DPEAS is in current operational use at NOAA/NESDIS Office of Satellite and Product Operations (OSPO) and performs multi-product data fusion of global "blended" Total Precipitable Water (bTPW) and blended Rainfall Rate (bRR). In this work we highlight: 1) the current dynamic inter-satellite calibration processing performed within the DPEAS data fusion and error analysis, 2) as well as our DPEAS development plans for future blended products (AMSR-2 and Megha-Tropiques), and 3) layered TPW products using the NASA AIRS data for National Weather Service forecaster use via the NASA SPoRT facility at Huntsville, AL. We also discuss new system additions for cloud verification and prediction activities in collaboration with the National Center for Atmospheric Research (NCAR), and planned use with the USAF Air Force Weather Agency's (AFWA) global Cloud Depiction and Forecast System (CDFS) facilities. Scientifically, we focus on the data fusion of atmospheric and land surface product information, including global cloud and water vapor data sets, soil moisture data, and specialized land surface products. The data fusion methods include the use of 1DVAR data assimilation for satellite sounding data sets, and numerous real-time statistical analysis methods. Our new development activities to extend the current 1DVAR algorithm to use and test a new non-Gaussian data assimilation method are presented. This research was supported by multiple grants from the NOAA/NESDIS Product System Development and Implementation (PSDI) program, a NASA ROSES grant, and a grant by the Air Force Weather Agency (AFWA) to the DoD Center for Geosciences / Atmospheric Research (CG/AR) at Colorado State University, as well as a subcontract from the National Center for Atmospheric Research (NCAR) to CSU.

Jones, A. S.; Fletcher, S. J.; Kidder, S. Q.; Forsythe, J. M.

2012-12-01

164

Analysis of stellar radiance contamination in observed satellite spectra  

NASA Astrophysics Data System (ADS)

Reflectance spectra of Earth orbiting satellites can be readily observed with small diameter telescopes (D < 1 m) by utilizing a method known as slitless spectroscopy. Satellite spectra can be observed by simply placing a transmission grating within the collimated optical path of the telescope without the need to image through a slit. The simplicity of the slitless spectroscopy design makes it a promising alternative to spatially resolving satellites with larger and more expensive diameter telescopes for applications of space situational awareness. However, accurately observing satellite re ectance spectra without imaging through a slit requires a dark and homogeneous background. This requirement is frequently violated as background stars streak across the image due to the slewing motion of the telescope during satellite tracking. Rather than throwing out all images with noticeable stellar contamination, a principle component analysis of contaminated images from three geostationary satellite observations showed that it may still be possible to assess and identify satellite characteristics depending upon the amount of stellar contamination in the spectral region of interest. Additionally, a simple technique for automatic removal of contaminated frames is proposed based on an outlier analysis using Gaussian statistics and was found to successfully remove all signicantly contaminated frames.

Vincent, R. Anthony; Chun, Francis K.; Dearborn, Michael E.; Tippets, Roger D.

2012-09-01

165

A study of satellite emergency locator systems  

NASA Technical Reports Server (NTRS)

Satellite emergency locator systems were studied. The objective of the study was to determine the feasibility and hardware requirements for satellite systems capable of identifying and locating the position emergency locator transmitters and emergency position indicating radio beacons. Both geosynchronous and near-polar-orbiting satellites were considered. One of the most important aspects of the study was to minimize the cost of the hardware required.

1977-01-01

166

Observing tectonic plate motions and deformations from satellite laser ranging  

NASA Technical Reports Server (NTRS)

The scope of geodesy has been greatly affected by the advent of artificial near-earth satellites. The present paper provides a description of the results obtained from the reduction of data collected with the aid of satellite laser ranging. It is pointed out that dynamic reduction of satellite laser ranging (SLR) data provides very precise positions in three dimensions for the laser tracking network. The vertical components of the stations, through the tracking geometry provided by the global network and the accurate knowledge of orbital dynamics, are uniquely related to the center of mass of the earth. Attention is given to the observations, the methodologies for reducing satellite observations to estimate station positions, Lageos-observed tectonic plate motions, an improved temporal resolution of SLR plate motions, and the SLR vertical datum.

Christodoulidis, D. C.; Smith, D. E.; Kolenkiewicz, R.; Klosko, S. M.; Torrence, M. H.

1985-01-01

167

ECC Ozonesonde Calibration and Observations: Satellite Validation  

NASA Technical Reports Server (NTRS)

The reliability of the Electrochemical Concentration Cell (ECC) ozonesonde depends on the care exercised in preparing the instrument for use. Although the ECC can be quickly prepared and flown, generally within less then one day if necessary, it is best to prepare the instrument at least one week prior to use, and as our tests have confirmed even 2-3 weeks prior to use may actually be better. There are a number of factors that must be considered when preparing an ECC. These basically are the pump efficiency, volumetric flow rate, temperature of the air entering the pump, and the background current. Also of importance is the concentration of the potassium iodide solution. Tests conducted at Wallops Island (38 N) has enabled us to identify potential problem areas and ways to avoid them. The calibration and pre-flight preparation methods will be discussed. The method of calibrating the ECC also is used at Ascension Island (8 S) and Natal, Brazil (5 S). Comparisons between vertical profiles of the ECC instrument and satellites will be reviewed as well as comparison with ground based instruments, such as, the Dobson Spectrophotometer and hand held Microtops photometers.

Schmidlin, Francis J.; Zukor, Dorothy (Technical Monitor)

2001-01-01

168

Satellite Significant Wave Height Observations in Coastal and Shelf Seas  

NASA Astrophysics Data System (ADS)

Significant wave height (SWH) observations from the Jason-1 satellite are compared against buoy observations and a spectral wave model for the North Sea/Baltic Sea region. The comparisons are from year 2005 and demon- strate that the satellite SWH observations are very con- sistent, with a mean bias of 0.07 m and a standard devi- ation of 0.36 m when compared with buoys. The error statistics have been derived for the individual buoys and a detailed validation of the wave model is carried out us- ing the satellite observations. It is shown that the 20 Hz std dev of SWH can be used as an indicator of the quality of the observations and that a significant amount of near coastal observations can be obtained even within 10 km from the coast.

Høyer, J. L.; Nielsen, J. W.

2006-07-01

169

US EPA: A USER AGENCY PERSPECTIVE ON POLAR SATELLITE OBSERVATIONS  

EPA Science Inventory

The Agency uses satellite sensor observations in its work on measuring, monitoring and modeling the environment and human health. It generates observations in collaboration with states, local and regional governments, tribes and others, and is a consumer of observations from a v...

170

The Public Broadcasting Satellite Interconnection System.  

ERIC Educational Resources Information Center

A satellite system to interconnect the Public Broadcasting Service (PBS) and 165 public television stations (PTV) is planned to replace the present terrestrial system. Stations are located on and outside of the United States mainland. Advantages offered by satellite are: (1) equal cost of program originations from points close to and remote from…

Ball, John E. D.

171

Solar System Observations with NHST  

Microsoft Academic Search

Solar system observations using HST have been tremendously successful in many scientific areas, taking advantage of the wealth of information from high angular resolution images and high sensitivity UV to IR spectra. These capabilities have led to major advances in the areas of planetary atmospheres, surfaces, aurora and magnetospheres, and planetary satellites. While solar system objects are normally considered to

J. T. Clarke

2003-01-01

172

Joint Polar Satellite System Common Ground System Overview  

NASA Astrophysics Data System (ADS)

The National Oceanic and Atmospheric Administration (NOAA) and National Aeronautics and Space Administration (NASA) are jointly acquiring the next-generation civilian weather and environmental satellite system: the Joint Polar Satellite System (JPSS). JPSS will contribute the afternoon orbit component and ground processing system of the restructured National Polar-orbiting Operational Environmental Satellite System (NPOESS). As such, JPSS replaces the current Polar-orbiting Operational Environmental Satellites (POES) managed by NOAA and the ground processing component of both Polar-orbiting Operational Environmental Satellites and the Defense Meteorological Satellite Program (DMSP) replacement, previously known as the Defense Weather Satellite System (DWSS), managed by the Department of Defense (DoD). The JPSS satellites will carry a suite of sensors designed to collect meteorological, oceanographic, climatological, and solar-geophysical observations of the earth, atmosphere, and space. The ground processing system for JPSS is known as the JPSS Common Ground System (JPSS CGS), and consists of a Command, Control, and Communications Segment (C3S) and an Interface Data Processing Segment (IDPS). Both segments are developed by Raytheon Intelligence and Information Systems (IIS). The C3S currently flies the Suomi National Polar Partnership (Suomi NPP) satellite and transfers mission data from Suomi NPP and between the ground facilities. The IDPS processes Suomi NPP satellite data to provide Environmental Data Records (EDRs) to NOAA and DoD processing centers operated by the United States government. When the JPSS-1 satellite is launched in early 2017, the responsibilities of the C3S and the IDPS will be expanded to support both Suomi NPP and JPSS-1. The JPSS CGS currently provides data processing for Suomi NPP, generating multiple terabytes per day across over two dozen environmental data products; that workload will be multiplied by two when the JPSS-1 satellite is launched. The CGS also provides raw data processing for GCOM-W1 to support further processing by NOAA. The CGS provides data routing for numerous missions, including Coriolis/Windsat, NASA SCaN (including EOS), DMSP, POES and Metop. Each of these satellites orbits the Earth 14 times a day, downlinking mission data once or twice per orbit at up to hundreds of megabits per second, to support the generation of tens of terabytes per day across hundreds of environmental data products. This presentation will provide an overview of the JPSS CGS ground architecture features, ConOps, key specifications, developmental and operational facilities, present and future supported missions, and recent enhancements for support of the Suomi NPP mission. Key features include redundant mission management, a global commercial communications network for data routing and delivery, high-availability and low-latency data processing, a DoD 8500 compliant security posture, and a modular and extensible architecture. Key recent enhancements include a technology refresh of IDPS hardware to improve supportability and latency performance, incorporation of data routing and processing for the Global Change Observation Mission (GCOM), and significant software upgrades to improve overall system robustness and operability. These enhancements lay the foundation for the future evolution of the CGS to support additional missions.

Jamilkowski, M. L.; Miller, S. W.; Grant, K. D.

2012-12-01

173

CEOS Committee on Earth Observations Satellites Consolidated Report, 1992  

NASA Technical Reports Server (NTRS)

A concise overview of the committee on Earth Observations Satellites (CEOS) and its Working Groups, covering the history and purpose of the Committee and its accomplishments to date are provided. The report will be updated annually before each Plenary meeting, and as developments in the Working Groups warrant. The committee on Earth Observations Satellites (originally named the International Earth Observations Satellite committee, IEOS) was treated in 1984, in response to a recommendation from the Economic Summit of Industrialized Nations Working Group on Growth, Technology, and Employment's Panel of Experts on Satellite Remote Sensing. This group recognized the multidisciplinary nature of satellite Earth observations, and the value of coordinating across all proposed missions. Thus, CEOS combined the previously existing groups for coordination on Ocean Remote-Sensing Satellites (CORSS) and coordination on Land Remote-Sensing Satellites (CLRSS), and established a broad framework for coordination across all spaceborne Earth observations missions. The first three LEOS Plenary meetings focused on treating and guiding the Working Groups deemed necessary to carry out the objectives of the CEOS members. After the third meeting, it was agreed that a more active orientation was required by the Plenary, and additional issues were brought before the group at the fourth meeting. At the fifth Plenary, international scientific programs and relevant intergovernmental organizations accepted invitations and participated as affiliate members of CEOS. This enabled progress toward integrating satellite data users' requirements into the CEOS process. Data exchange principles for global change research were also adopted. An interim CEOS Plenary meeting was held in April 1992, in preparation for the United Nations Conference on Environment and Development (UNCED). Brief encapsulations of the Plenary sessions immediately follow the Terms of Reference that govern the activities of CEOS as a whole; Terms of Reference for the individual Working Groups are included as Appendix A. A complete listing of CEOS members is offered as Appendix B.

1992-01-01

174

Recent state of the Aral sea from regular satellite observations.  

NASA Astrophysics Data System (ADS)

The Aral Sea disaster is one of the most significant examples of ecological catastrophe caused by mismanagement of water resources. Aral sea level dropped on 22 meters for the last 35 years. The sea separated in to two independent parts , the Large Sea(Southern) and the Small Sea (Northern), loosing more than 90% of its original water masses. After the collapse of the former Soviet Union, satellite retrieved data became the main source of information on this perishing system. Regular observations from AVHRR, SeaWiFS, MODIS and ASTER satellite sensors were used for our investigations. Sea surface temperature (SST) data of the AVHRR sensor and digital bottom map topography were used for sea level drop calculations. The Sea level defined as the digital map isobate corresponds quite well to the satellite derived coastline for the Eastern part of the Large Sea with a bottom slope of ˜ 0.00015. For the period 1989-2002 the sea level of the Large Sea dropped on 9.2 meters. However in 2003 the sea level remained stable. This stabilisation was due to an increase of water output of the rivers Amu--Darya and Syr-Darya in 2003. High resolution ASTER data showed that the main amount of Syr-Darya waters is discharged into the Large Sea. The dried bottom area now covers more than 45000 km2. On the base of AVHRR-SST data the temperature regime for different parts of the Aral Sea was calculated for the years 2002-2003. The annual amplitude of the SST variation reaches 37° C for the open waters. The observed minimum freezing point was -7° C due to very high salinity. Estimations from satellite retrieved freezing points show an increase of salinity up to 10% in the Eastern part of the Large Sea. It is almost paradox that on satellite images the ice appears warmer than the water. Strong variations of the water temperature (up to 5° C) within a few days could be observed from April to August and could be related to wind induced mixing. SeaWiFS ocean colour data were used for the investigation of the optical properties of the water in different parts of the Aral Sea for the years 2002-2003. A significant relation of optical properties with wind and temperature was obtained. Strong changes of the thermal regimes of the Sea can cause variations in local climatic conditions: The analysis of AVHRR NDVI - data for the surrounding areas demonstrated a shift in the annual vegetation cycle. In addition phenomena like: salt storms, wind driven tides, sources of groundwater, eddies and frontal structures as well as ice coverage of the Aral Sea were demonstrated on satellite images.

Stanichny, S.; Davidov, A.; Djenidi, S.; Horstmann, U.; Stanichnaya, R.; Soloviev, D.

175

Satellite Television Corporations's DBS system - An update  

NASA Astrophysics Data System (ADS)

In late 1980, a request was made for approval of a direct broadcast satellite (DBS) system. The considered DBS system is to provide nationwide pay-television service on a subscription basis. The system proposed in the application to the Federal Communications Commission would provide three channels of television, using four three-channel satellites. Attention is given to the system configuration, system tradeoffs, a plan of the 1983 Regional Administrative Radio Conference, orbit locations and channel frequencies, satellite status, home equipment status, advanced concepts, and the status of the Las Vegas Broadcast Complex. AIAA Paper 84-0664

Martin, E. R.

176

Observation of solid precipitation using satellite gravity  

Microsoft Academic Search

Understanding hydrological processes in the arctic region and their variation are emerging and important issues in the association with global climate changes. Solid precipitation is particularly important because it plays a major role in controlling the winter hydrological cycle and spring discharge. Nevertheless, observations of winter snowfall in high latitudes is challenging due to sharply decreasing numbers of precipitation gauges

K. Seo; D. E. Waliser; D. Ryu; B. Tian; B. Kim

2009-01-01

177

Satellite-based observations of hydrological processes  

Microsoft Academic Search

This special issue of the International Journal of Remote Sensing is based on papers presented in a special session at the American Geophysical Union (AGU) 2008 Fall Meeting in San Francisco. The session consisted of 85 contributions from the research, operational and user communities that addressed various applications of remote sensing observations in the development, improvement, validation and use of

Qiuhong Tang; Michael Durand; Dennis P. Lettenmaier; Yang Hong

2010-01-01

178

Observation of suspended sediments in Mobile Bay, Alabama from satellite  

USGS Publications Warehouse

As part of a comprehensive geologic study of coastal Alabama and Mississippi, the U.S. Geological Survey is investigating coastal sediment transport in Mobile Bay and the adjacent shelf. Satellite imagery from the NOAA AVHRR is being used to provide data on the variability of spatial patterns in the near-surface suspended sediment concentration. This imagery is processed using atmospheric corrections to remove haze and Rayleigh radiance in order to obtain water reflectances; the reflectances are than converted to approximate sediment concentrations using standard relationships between water reflectance and in situ sediment concentrations. A series of images from early 1990 shows rapid changes in sediment concentrations in response to high river flow of the Alabama-Tombigbee river system. During these times, suspended sediment tends to flow out Mobile Bay without mixing into the eastern lobe of the Bay (Bon Secour Bay). The sediment concentration field also appears to be disturbed by the main ship channel. The sediment plume extends more than 60 km offshore after the peak flow event. One wind event in December 1989 was identified as increasing sediment concentration in the Bay. It is not believed that such an event has been previously observed from satellite.

Stumpf, Richard P.

1991-01-01

179

Global Positioning System Satellite Selection Method  

NASA Technical Reports Server (NTRS)

The satellite selection method as utilized by the spaceborne Global Positioning System receiver provides navigational solutions and is designed for use in low Earth orbit. The satellite selection method is a robust algorithm that can be used a GPS receiver to select appropriate GPS satellites for use in calculating point solutions or attitude solutions. The method is takes into account the difficulty of finding a particular GPS satellite phase code, especially when the search range in greatly increased due to Doppler shifts introduced into the carrier frequency. The method starts with an update of the antenna pointing and spacecraft vectors to determine the antenna backplane direction. Next, the GPS satellites that will potentially be in view of the antenna are ranked on a list, whereby the list is generated based on the estimated attitude and position of each GPS satellite. Satellites blocked by the Earth are not entered on this list. A second list is created, whereby the GPS satellites are ranked according to their desirability for use in attitude determination. GPS satellites are ranked according to their orthogonality to the antenna backplane, and according to geometric dilution of precision considerations. After the lists are created, the channels of the spaceborne GPS receiver are assigned to various GPS satellites for acquisition and lock. Preliminary Doppler frequencies for searching are assigned to the various channels.

Niles, Frederick A. (Inventor)

2001-01-01

180

Satellite systems for Latin American telecommunication requirements  

NASA Astrophysics Data System (ADS)

Aspects of satellite telecommunications systems of interest to Latin America are discussed. Presently existing systems are described, including both state-run and international services. Services planned for the region are examined, including Geostar, a service that provides satellite radio determination and message services, a system which will provide a high-capacity digital voice and data service for airlines, and direct broadcast satellites. Applications of these systems in education, rural telephony, data transmission, news services, publishing, emergency communications, and mobile communications are addressed.

Elizondo, Eduardo L.

181

Observations of Uranus' satellites: Bibliography and literature search  

NASA Technical Reports Server (NTRS)

A literature search has yielded more than 10,000 observations of the satellites of Uranus made from 1787 to 1985. The type (photographic, micrometer) and the number of observations are tabulated in 5 year increments and a complete bibliography is provided.

Jacobson, R. A.

1985-01-01

182

Solar power satellite system definition study  

NASA Technical Reports Server (NTRS)

A synopsis of the study plan for the solar power satellite system is presented. Descriptions of early task progress is reported for the following areas: (1) laser annealing, (2) solid state power amplifiers, (3) rectenna option, (4) construction of an independent electric orbit transfer vehicle, and (5) construction of a 2.5 GW solar power satellite.

1978-01-01

183

Power Control Algorithms for Satellite Communication Systems  

Microsoft Academic Search

Three different ground terminal transmit power control concepts for a Satcom system are examined. The effectiveness of constant satellite power (CSP) sharing among the carriers and adaptive satellite power (ASP) sharing is compared with constant ground terminal transmit power (CTP). It is shown that ASP offers substantial advantages over CSP in combating environmental degradations and that both can increase link

A. Ince; D. Brown; J. Midgley

1976-01-01

184

Planning and Scheduling for Fleets of Earth Observing Satellites  

NASA Technical Reports Server (NTRS)

We address the problem of scheduling observations for a collection of earth observing satellites. This scheduling task is a difficult optimization problem, potentially involving many satellites, hundreds of requests, constraints on when and how to service each request, and resources such as instruments, recording devices, transmitters, and ground stations. High-fidelity models are required to ensure the validity of schedules; at the same time, the size and complexity of the problem makes it unlikely that systematic optimization search methods will be able to solve them in a reasonable time. This paper presents a constraint-based approach to solving the Earth Observing Satellites (EOS) scheduling problem, and proposes a stochastic heuristic search method for solving it.

Frank, Jeremy; Jonsson, Ari; Morris, Robert; Smith, David E.; Norvig, Peter (Technical Monitor)

2001-01-01

185

Tracking and Data Relay Satellite System (TDRSS)  

NASA Technical Reports Server (NTRS)

The DSN (Deep Space Network) mission support requirements for the Tracking and Data Relay Satellite System (TDRSS) are summarized. The TDRSS consists of four identical satellites in geosynchronous orbits (35,800 km) and a dedicated ground station. The payload of each satellite is a telecommunications service system that relays communication signals between low earth-orbiting user spacecraft and the TDRSS ground terminal. Mission objectives are outlined and the DSN support requirements are defined through the presentation of tables and narratives describing the spacecraft flight profile; DSN support coverage; frequency assignments; support parameters for telemetry, command and support systems; and tracking support responsibility.

Mckenzie, J.; Vanek, C.

1991-01-01

186

Domestic satellite communications systems - Background and projections  

NASA Astrophysics Data System (ADS)

Planned and existing national and international communications satellites are reviewed, along with comparative costs for leasing or owning a satellite and the basic capabilities of communications spacecraft. Eleven different satellite communications systems existed in 1982, including Intelsat, Marisat/Inmarsat, and Intersputnik as the international segments, and the Molniya, Telesat, Palapa, Westar, Satcom, Comstar, Amersat, and the SBS national systems. Seven of the twenty countries leasing Intelsat services are planning their own satellites. Leasing permits full capabilities withno development costs and ensures the lessor of full use of the satellite capacities. Developing countries can then gain hands-on experience with space technologies. Future demands are discussed, noting the broadening of the available bandwidths, better orbit utilization, and increases in transponder numbers to handle increased loads in future spacecraft.

Bargellini, P. L.

187

Satellite observations of the global distribution of stratospheric ozone  

NASA Technical Reports Server (NTRS)

Observations of backscattered radiation from an Orbiting Geophysical Observatory (OGO) Satellite were used to determine the global distribution of ozone in different layers in the middle and upper stratosphere. The derived distributions show significant seasonal and geographic variations with important differences indicated between winter and summer hemisphere distributions. The OGO derived distributions are compared with other observations (rocket and satellite) and with photochemical calculations. It is suggested that the increased ozone mixing ratio in the high latitude winter hemisphere can be accounted for by transport processes up to about 40-45 km and by the effects of seasonal variations of NOX, HOX and temperature in the region above.

London, J.; Frederick, J. E.; Anderson, G. P.

1976-01-01

188

A Satellite Observation Information Service for Data Assimilation Applications  

NASA Astrophysics Data System (ADS)

Multi-mission Observation Operator (M2O2) team at NASA is developing a streamlined interface mechanism that simplifies the assimilation process of satellite-observations by providing 'assimilation-ready' observation information 'on-demand'. The 'assimilation-ready' observation information is referred to as L2# (L2-sharp) data in contrast to level-2 (L2) data. The 'on-demand' indicates a web-service protocol for L2# data request handling. A L2# data service is developed for each atmospheric component of a mission to apply component-specific quality screening and post processing and deliver mission-generic observation information required for assimilation. The observation information is organized for sampling (time and location), sounding (pressure profile and averaging kernel), and retrieval results (a priori state, estimated state, and error). The M2O2 extensions to GEOS-Chem (version 9.0.1) and GEOS-Chem-Adjoint (version 34) have been employed to assimilate MLS-O3 (2004-2012), TES-O3 (2005-2009), TES-CH4 (2009) and ACOS-XCO2 (2009-2011). The L2# data services for MLS-O3 (2004-current), ACOS-XCO2 (2009-current), and AIRS-CO (2002-current) have been installed at GES DISC for assimilation-community-wide access. We will present the 'lessons learned' in three areas: 1) diversity of level-2 data product organization, 2) observation information formulation and validation, and 3) generalized model-coupling process. The M2O2 research is supported by NASA's Advancing Collaborative Connections for Earth System Science (ACCESS) program.

Lee, M.; Weidner, R. J.; Lynnes, C.; Gerasimov, I. V.

2013-12-01

189

Overview of the Upper Atmosphere Research Satellite: Observations from 1991 to 2002  

NASA Technical Reports Server (NTRS)

The Upper Atmosphere Research Satellite (UARS) was launched in September 1991 by the Space Shuttle Discovery and continues to make relevant atmospheric measurements (as of October 2002). This successful satellite has fostered a better understanding of the middle atmospheric processes, especially those important in the control of ozone. Seven of the original ten instruments aboard the UARS are still functional and six instruments regularly make measurements. The UARS is in a stable observing configuration, in spite of experiencing several anomalies over its lifetime. It is expected that the UARS will overlap the Earth Observing System (EOS) Aura satellite (scheduled launch in January 2004) for several months before the end of the UARS mission.

Jackman, Charles H.; Douglass, Anne R.

2003-01-01

190

A new digital land mobile satellite system  

NASA Astrophysics Data System (ADS)

A description is given of the different digital services planned to be carried over existing and planned mobile satellite systems. These systems are then compared with analog services in terms of bandwidth and power efficiency. This comparison provides the rationale for the establishment of a digital land mobile satellite service (DLMSS) to use frequencies that are currently available but not yet assigned to a domestic mobile satellite system in the United States. The focus here is on the expected advantages of digital transmission techniques in accommodating additional mobile satellite systems in this portion of the spectrum, and how such techniques can fully satisfy voice, data and facsimile mobile communications requirements in a cost effective manner. A description is given of the system architecture of the DMLSS service proposed by the Geostar Messaging Corporation (GMC) and the market potential of DLMSS.

Schneider, Philip

191

A new digital land mobile satellite system  

NASA Technical Reports Server (NTRS)

A description is given of the different digital services planned to be carried over existing and planned mobile satellite systems. These systems are then compared with analog services in terms of bandwidth and power efficiency. This comparison provides the rationale for the establishment of a digital land mobile satellite service (DLMSS) to use frequencies that are currently available but not yet assigned to a domestic mobile satellite system in the United States. The focus here is on the expected advantages of digital transmission techniques in accommodating additional mobile satellite systems in this portion of the spectrum, and how such techniques can fully satisfy voice, data and facsimile mobile communications requirements in a cost effective manner. A description is given of the system architecture of the DMLSS service proposed by the Geostar Messaging Corporation (GMC) and the market potential of DLMSS.

Schneider, Philip

1990-01-01

192

Asian Dust Weather Categorization with Satellite and Surface Observations  

NASA Technical Reports Server (NTRS)

This study categorizes various dust weather types by means of satellite remote sensing over central Asia. Airborne dust particles can be identified by satellite remote sensing because of the different optical properties exhibited by coarse and fine particles (i.e. varying particle sizes). If a correlation can be established between the retrieved aerosol optical properties and surface visibility, the intensity of dust weather can be more effectively and consistently discerned using satellite rather than surface observations. In this article, datasets consisting of collocated products from Moderate Resolution Imaging Spectroradiometer Aqua and surface measurements are analysed. The results indicate an exponential relationship between the surface visibility and the satellite-retrieved aerosol optical depth, which is subsequently used to categorize the dust weather. The satellite-derived spatial frequency distributions in the dust weather types are consistent with China s weather station reports during 2003, indicating that dust weather classification using satellite data is highly feasible. Although the period during the springtime from 2004 to 2007 may be not sufficient for statistical significance, our results reveal an increasing tendency in both intensity and frequency of dust weather over central Asia during this time period.

Lin, Tang-Huang; Hsu, N. Christina; Tsay, Si-Chee; Huang, Shih-Jen

2011-01-01

193

EUV observation from the Earth-orbiting satellite, EXCEED  

Microsoft Academic Search

An Earth-orbiting small satellite “EXtreme ultraviolet spectrosCope for ExosphEric Dynamics” (EXCEED) which will be launched in 2012 is under development. The mission will carry out spectroscopic and imaging observation of EUV (Extreme Ultraviolet: 60–145nm) emissions from tenuous plasmas around the planets (Venus, Mars, Mercury, and Jupiter). It is essential for EUV observation to put on an observing site outside the

K. Yoshioka; G. Murakami; I. Yoshikawa; M. Ueno; K. Uemizu; A. Yamazaki

2010-01-01

194

A small terminal for satellite communication systems  

NASA Technical Reports Server (NTRS)

A small portable, low-cost satellite communications terminal system incorporating a modulator/demodulator and convolutional-Viterbi coder/decoder is described. Advances in signal processing and error-correction techniques in combination with higher power and higher frequencies aboard satellites allow for more efficient use of the space segment. This makes it possible to design small economical earth stations. The Advanced Communications Technology Satellite (ACTS) was chosen to test the system. ACTS, operating at the Ka band incorporates higher power, higher frequency, frequency and spatial reuse using spot beams and polarization.

Xiong, Fuqin; Wu, Dong; Jin, Min

1994-01-01

195

Satellite voice broadcast. Volume 2: System study  

NASA Technical Reports Server (NTRS)

The Technical Volume of the Satellite Broadcast System Study is presented. Designs are synthesized for direct sound broadcast satellite systems for HF-, VHF-, L-, and Ku-bands. Methods are developed and used to predict satellite weight, volume, and RF performance for the various concepts considered. Cost and schedule risk assessments are performed to predict time and cost required to implement selected concepts. Technology assessments and tradeoffs are made to identify critical enabling technologies that require development to bring technical risk to acceptable levels for full scale development.

Bachtell, E. E.; Bettadapur, S. S.; Coyner, J. V.; Farrell, C. E.

1985-01-01

196

Satellite power system (SPS) initial insurance evaluation  

SciTech Connect

The beginning of a process to educate the insurance industry about the Satellite Power System is reported. The report is divided into three sections. In the first section a general history describes how space risks are being insured today. This is followed by an attempt to identify the major risks inherent to the SPS. The final section presents a general projection of insurance market reactions to the Satellite Power System.

None

1980-09-01

197

NASA Satellite Observations: A Unique Asset for the Study of the Environment and Implications for Public Health  

NASA Technical Reports Server (NTRS)

This slide presentation highlights how satellite observation systems are assets for studying the environment in relation to public health. It includes information on current and future satellite observation systems, NASA's public health and safety research, surveillance projects, and NASA's public health partners.

Estes Sue M.

2010-01-01

198

Satellite antenna management system and method  

NASA Technical Reports Server (NTRS)

The antenna management system and method allow a satellite to communicate with a ground station either directly or by an intermediary of a second satellite, thus permitting communication even when the satellite is not within range of the ground station. The system and method employ five major software components, which are the control and initialization module, the command and telemetry handler module, the contact schedule processor module, the contact state machining module, and the telemetry state machine module. The control and initialization module initializes the system and operates the main control cycle, in which the other modules are called. The command and telemetry handler module handles communication to and from the ground station. The contact scheduler processor module handles the contact entry schedules to allow scheduling of contacts with the second satellite. The contact and telemetry state machine modules handle the various states of the satellite in beginning, maintaining and ending contact with the second satellite and in beginning, maintaining and ending communication with the satellite.

Leath, Timothy T (Inventor); Azzolini, John D (Inventor)

1999-01-01

199

Gravity waves in the thermosphere observed by the AE satellites  

NASA Technical Reports Server (NTRS)

Atmospheric Explorer (AE) satellite data were used to investigate the spectra characteristics of wave-like structure observed in the neutral and ionized components of the thermosphere. Power spectral analysis derived by the maximum entropy method indicate the existence of a broad spectrum of scale sizes for the fluctuations ranging from tens to thousands of kilometers.

Gross, S. H.; Reber, C. A.; Huang, F. T.

1983-01-01

200

Recent La Plata basin drought conditions observed by satellite gravimetry  

E-print Network

Recent La Plata basin drought conditions observed by satellite gravimetry J. L. Chen,1 C. R. Wilson over the period 2002­2009, consistent with recognized drought conditions in the region. GRACE data reveal a detailed picture of temporal and spatial evolution of this severe drought event, which suggests

Yang, Zong-Liang

201

Greenland surface albedo changes 1981-2012 from satellite observations  

Technology Transfer Automated Retrieval System (TEKTRAN)

Significant melt over Greenland has been observed during the last several decades associated with extreme warming events over the northern Atlantic Ocean. An analysis of surface albedo change over Greenland is presented, using a 32-year consistent satellite albedo product from the Global Land Surfac...

202

CORRECTING PHOTOLYSIS RATES ON THE BASIS OF SATELLITE OBSERVED CLOUDS  

EPA Science Inventory

Clouds can significantly affect photochemical activities in the boundary layer by altering radiation intensity, and therefore their correct specification in the air quality models is of outmost importance. In this study we introduce a technique for using the satellite observed c...

203

Sensor Web Interoperability Testbed Results Incorporating Earth Observation Satellites  

NASA Technical Reports Server (NTRS)

This paper describes an Earth Observation Sensor Web scenario based on the Open Geospatial Consortium s Sensor Web Enablement and Web Services interoperability standards. The scenario demonstrates the application of standards in describing, discovering, accessing and tasking satellites and groundbased sensor installations in a sequence of analysis activities that deliver information required by decision makers in response to national, regional or local emergencies.

Frye, Stuart; Mandl, Daniel J.; Alameh, Nadine; Bambacus, Myra; Cappelaere, Pat; Falke, Stefan; Derezinski, Linda; Zhao, Piesheng

2007-01-01

204

Globally Gridded Satellite (GridSat) Observations for Climate Studies  

NASA Technical Reports Server (NTRS)

Geostationary satellites have provided routine, high temporal resolution Earth observations since the 1970s. Despite the long period of record, use of these data in climate studies has been limited for numerous reasons, among them: there is no central archive of geostationary data for all international satellites, full temporal and spatial resolution data are voluminous, and diverse calibration and navigation formats encumber the uniform processing needed for multi-satellite climate studies. The International Satellite Cloud Climatology Project set the stage for overcoming these issues by archiving a subset of the full resolution geostationary data at approx.10 km resolution at 3 hourly intervals since 1983. Recent efforts at NOAA s National Climatic Data Center to provide convenient access to these data include remapping the data to a standard map projection, recalibrating the data to optimize temporal homogeneity, extending the record of observations back to 1980, and reformatting the data for broad public distribution. The Gridded Satellite (GridSat) dataset includes observations from the visible, infrared window, and infrared water vapor channels. Data are stored in the netCDF format using standards that permit a wide variety of tools and libraries to quickly and easily process the data. A novel data layering approach, together with appropriate satellite and file metadata, allows users to access GridSat data at varying levels of complexity based on their needs. The result is a climate data record already in use by the meteorological community. Examples include reanalysis of tropical cyclones, studies of global precipitation, and detection and tracking of the intertropical convergence zone.

Knapp, Kenneth R.; Ansari, Steve; Bain, Caroline L.; Bourassa, Mark A.; Dickinson, Michael J.; Funk, Chris; Helms, Chip N.; Hennon, Christopher C.; Holmes, Christopher D.; Huffman, George J.; Kossin, James P.; Lee, Hai-Tien; Loew, Alexander; Magnusdottir, Gudrun

2012-01-01

205

Solar absorption over Europe from collocated surface and satellite observations  

NASA Astrophysics Data System (ADS)

Solar radiation is the primary source of energy for the Earth's climate system. Although the incoming and outgoing solar fluxes at the top of atmosphere can be quantified with high accuracy, large uncertainties still exist in the partitioning of solar absorption between surface and atmosphere. To compute best estimates of absorbed solar radiation at the surface and within the atmosphere representative for Europe during 2000-2010, we combine temporally homogeneous and spatially representative ground-based observations of surface downwelling solar radiation with collocated satellite-retrieved surface albedo and top-of-atmosphere net irradiance. We find best estimates of Europe land annual mean surface and atmospheric absorption of 117.3 ± 6 W m-2 (41.6 ± 2% of top-of-atmosphere incident irradiance) and 65.0 ± 3 W m-2 (23.0 ± 1%). The fractional atmospheric absorption of 23% represents a robust estimate largely unaffected by variations in latitude and season, thus, making it a potentially useful quantity for first-order validation of regional climate models. Uncertainties of the individual absorption estimates arise mostly from the measurements themselves. In this context, the surface albedo and the ground-based solar radiation data are the most critical variables. Other sources of uncertainty, like the multiplicative combination of spatially averaged surface solar radiation and surface albedo estimates, and the spatial representativeness of the point observations, are either negligibly small or can be corrected for.

Hakuba, M. Z.; Folini, D.; Schaepman-Strub, G.; Wild, M.

2014-03-01

206

Satellite observations of transient radio impulses from thunderstorms  

SciTech Connect

Transient radio emissions from thunderstorms detected by satellites were first reported in 1995. The nature and source of these emissions remained a mystery until the launch of the FORTE satellite in 1997. FORTE, with its more sophisticated triggering and larger memory capacity showed that these emissions were connected to major thunderstorm systems. The analysis reported here, connecting FORTE RF events with ground based lightning location data from the National Lightning Detection Network (NLDN), shows that localized regions within thunderstorms are responsible for the creation of the satellite detected rf signals. These regions are connected with the areas of strong radar returns from the NEXRAD Doppler radar system, indicating that they are from regions of intense convection. The authors will also show data from several storms detected in the extended Caribbean, in which the height profile of the source regions can be determined. Although as a single low earth orbit satellite FORTE cannot provide global coverage of thunderstorm/lightning events, follow-on satellite constellations should be able to provide detailed information on global lightning in near real-time.

Argo, P.E.; Kirkland, M.; Jacobson, A.; Massey, R.; Suszynsky, D.; Eack, K.; Fitzgerald, T.J.; Smith, D.

1999-06-01

207

Photoelectron flux variations observed from the FAST satellite  

Microsoft Academic Search

This paper examines high resolution (?E\\/E=0.15) photoelectron energy spectra from 10eV to 1keV, created by solar irradiances between 1.2 and 120nm. The observations were made from the FAST satellite at ?3000km, equatorward of the auroral oval for the July–August, 2002 solar rotation. These data are compared with the solar irradiance observed by the Solar EUV Experiment (SEE) on the Thermosphere

W. K. Peterson; T. N. Woods; P. C. Chamberlin; P. G. Richards

2008-01-01

208

Photoelectron flux variations observed from the FAST satellite  

Microsoft Academic Search

This paper examines high resolution (DeltaE\\/E = 0.15) photoelectron energy spectra from 10 eV to 1 keV, created by solar irradiances between 1.2 and 120 nm. The observations were made from the FAST satellite at ˜3000 km, equatorward of the auroral oval for the July August, 2002 solar rotation. These data are compared with the solar irradiance observed by the

W. K. Peterson; T. N. Woods; P. C. Chamberlin; P. G. Richards

2008-01-01

209

Coordinated ISTP satellite and ground observations of morningside  

Microsoft Academic Search

This paper reports the result of a coordinated data analysis of a morningside Pc5 event observed at different altitudes in the magnetosphere and also on the ground. The event took place during 1400-1500 UT of April 29, 1993. The Geotail satellite was located in the boundary region and observed a 5-min quasi-periodic magnetic oscillation. The oscillation was mostly transverse to

S. Ohtani; G. Rostoker; K. Takahashi; V. Angelopoulos; M. Nakamura; C. Waters; H. Singer; S. Kokubun; K. Tsuruda; W. J. Hughes; T. A. Potemra; L. J. Zanetti; J. B. Gary; A. T. Y. Lui; D. J. Williams

1999-01-01

210

Whistler-triggered emissions observed by ISIS satellites  

NASA Technical Reports Server (NTRS)

A statistical examination has been conducted of the ducted and nonducted whistler-triggered emissions (WTEs) observed by the ISIS satellites in the 1979-1981 period. Most WTEs are observed with simultaneous lower hybrid resonance in the topside ionosphere. The VLF emissions triggered by ducted whistlers frequently occur at L of 2-3, while those triggered by nonducted whistlers occur in the wider latitudinal regions at L of 2.2-4.3.

Nakamura, Y.; Ondoh, T.

1989-01-01

211

Voyager 2 photopolarimeter observations of the Uranian satellites  

NASA Technical Reports Server (NTRS)

The surfaces of the principal Uranian satellites are characterized on the basis of UV and IR geometric albedos, phase curves, and phase coefficients obtained in full-disk photopolarimetric observations during the Voyager 2 encounter with Uranus in January 1986. The data are presented in tables and graphs and found to be consistent with a heavily cratered terrain and loosely packed regolith. The Bond albedos are calculated as 0.22 + or - 0.1 for Ariel, 0.07 + or - 0.05 for Umbriel, 0.16 + or - 0.12 for Titania, and 0.19 + or - 0.22 for Oberon. The characteristics of the Uranian satellites indicate compositions (and probably formation conditions and surface-modification mechanisms) distinct from those of the Saturnian and Jovian satellites.

Nelson, Robert M.; Buratti, Bonnie J.; Wallis, Brad D.; Lane, Arthur L.; West, Robert A.

1987-01-01

212

SOFT project: a new forecasting system based on satellite data  

NASA Astrophysics Data System (ADS)

The aim of the SOFT project is to develop a new ocean forecasting system by using a combination of satellite dat, evolutionary programming and numerical ocean models. To achieve this objective two steps are proved: (1) to obtain an accurate ocean forecasting system using genetic algorithms based on satellite data; and (2) to integrate the above new system into existing deterministic numerical models. Evolutionary programming will be employed to build 'intelligent' systems that, learning form the past ocean variability and considering the present ocean state, will be able to infer near future ocean conditions. Validation of the forecast skill will be carried out by comparing the forecasts fields with satellite and in situ observations. Validation with satellite observations will provide the expected errors in the forecasting system. Validation with in situ data will indicate the capabilities of the satellite based forecast information to improve the performance of the numerical ocean models. This later validation will be accomplished considering in situ measurements in a specific oceanographic area at two different periods of time. The first set of observations will be employed to feed the hybrid systems while the second set will be used to validate the hybrid and traditional numerical model results.

Pascual, Ananda; Orfila, A.; Alvarez, Alberto; Hernandez, E.; Gomis, D.; Barth, Alexander; Tintore, Joaquim

2002-01-01

213

The Synchronous Meteorological Satellite /SMS/ system  

NASA Technical Reports Server (NTRS)

The Synchronous Meteorological Satellite (SMS) system is described which is being utilized in a program to obtain day and night information on the earth's weather by means of earth imaging, retransmission of imaged data, meteorological data collection and relay, and space environment monitoring. The components and functions of the ground system are discussed together with the basic satellite payloads. The launch and orbit of SMS-A are reviewed, and the functions of the visible IR spin-scan radiometer are described in detail. Other systems and units discussed include the data collection system, solar environment monitor, weather-facsimile unit, and central data distribution system. It is noted that SMS-A was used to support the Global Atlantic Tropical Experiment and that the SMS system will be complemented by geostationary environmental satellites from ESRO, Japan, and the USSR.

Fordyce, D. V.; Wirth, R. J.; Shenk, W. E.

1974-01-01

214

25-Year Ocean Wind Climatology from Satellite Observations  

NASA Astrophysics Data System (ADS)

A consistently processed ocean wind climatology derived from 10 satellite microwave sensors is now available. This array of satellites extends from 1987 to present and includes 6 SSM/I, AMSR-E, WindSat, F17 SSM/IS, and QuikScat. Two of the satellite sensors, WindSat and QuikScat, provide wind direction in addition to wind speed. This ocean wind climatology is the basis for the cross-calibrated, multi-platform (CCMP) wind product. CCMP assimilates these satellite winds along with conventional ship and buoy wind observations using the ECMWF analysis as a background field to produce 6-hour vector wind fields at a 25-km resolution. The satellite wind retrievals from these multi-platforms have been carefully inter-calibrated, and the typical annual, globally averaged differences among the satellites are less than 0.1 m/s. The error (2-sigma) in the resulting decadal wind trends over the 25-years is estimated to be about 0.06 m/s/decade. Observed large-scale regional wind trends can be as large as 0.5 m/s/decade and hence are well above the noise level of estimating trends. We will present an overview of the ocean wind climatology and the methodology used to inter-calibrate the various sensors. Wind timeseries from the various sensors will be inter-compared with each other and with ocean buoys. An analysis of estimated trend error will be presented. Finally, some examples of global wind trends over the last quarter century will be shown.

Wentz, F. J.; Ricciardulli, L.; Smith, D. K.

2012-12-01

215

Satellite autonomy enhances space system survivability  

NASA Astrophysics Data System (ADS)

An elementary but revolutionary solution to the current problem of satellite system ground support vulnerability is the elimination of satellite reliance on fixed location ground stations. Since neither the technology nor the confidence is currently available to render satellites entirely independent of human intervention, attention is given to the intermediate possibility of using mobile stations as more survivable ground support platforms. Nevertheless, the manpower restrictions imposed by the requirement for station mobility must be compensated for through the development of partial satellite autonomy. As in long mission duration interplanetary probes, autonomous fault detection and correction systems are essential to autonomy. Attention is accordingly given to an Autonomous Redundancy and Maintenance Management Subsystem concept, for which a schematic is provided.

Gjermundsen, E. I.

1984-02-01

216

Satellite Communication Hardware Emulation System (SCHES)  

NASA Technical Reports Server (NTRS)

Satellite Communication Hardware Emulator System (SCHES) is a powerful simulator that emulates the hardware used in TDRSS links. SCHES is a true bit-by-bit simulator that models communications hardware accurately enough to be used as a verification mechanism for actual hardware tests on user spacecraft. As a credit to its modular design, SCHES is easily configurable to model any user satellite communication link, though some development may be required to tailor existing software to user specific hardware.

Kaplan, Ted

1993-01-01

217

NASA Perspectives on Earth Observations from Satellite or 50 Years of Meteorological Satellite Experiments-The NASA Perspective  

NASA Technical Reports Server (NTRS)

The NASA was established in 1959. From those very eady days to the present NASA has been intimately involved with NOAA and the scientific community in the development and operation of satellite and sensor experiments. The early efforts included experiments on the TIROS and geostationary Applications Technology Satellites (ATS) series. In the latter case the spin-scan cameras conceived by Verner Suomi, along with the TIROS cameras, opened new vistas at what could be done in meteorological studies with the daily, nearly global, synoptic views from space-borne sensors As the years passed and the Nimbus series of satellites came into being in the 1960's, more quantitative observations with longer-lifetime, increasingly capable, better calibrated instruments came into being. NASA, in collaboration with and in support of NOAA, implemented operational systems that we now know as the Polar Operational Environmental Satellite (POES) series and the Geostationary Operational Environmental Satellite (GOES) series that provided dependable, continuous, dedicated satellite observations for use by the weather and atmospheric science communities. Through the 1970's, 1980's, and 1990's improved, well-calibrated instruments with more spectral bands extending into the thermal and the microwave portions of the electromagnetic spectrum were provided to obtain accurate soundings of the atmosphere, atmospheric chemistry constituents such as ozone, global sea surface temperature, snow and ice extent, vegetation dynamics, etc. In the 1990's and up to the present the NASA/Earth Observing System (EOS) has been developed, implemented, and operated over many years to provide a very comprehensive suite of observations of the atmosphere, as well as land and ocean parameters. The future looks bright wherein the development of new systems, broadly described by the National Academy of Science Decadal Study, is now underway. NASA, along with collaborations with NOAA, other agencies, and the scientific and applications communities looks forward to achieving in the years to come goals possible with the global information provided by satellites and continuously improved with technology development, joint data assimilation efforts, and attendant research studies.

Einaudi, Franco

2010-01-01

218

Modeling Prairie Pothole Lakes: Linking Satellite Observation and Calibration (Invited)  

Microsoft Academic Search

This paper examines the response of a complex lake wetland system to variations in climate. The focus is on the lakes and wetlands of the Missouri Coteau, which is part of the larger Prairie Pothole Region of the Central Plains of North America. Information on lake size was enumerated from satellite images, and yielded power law relationships for different hydrological

F. W. Schwartz; G. Liu; B. Zhang; Z. Yu

2009-01-01

219

Critical areas: Satellite power systems concepts  

NASA Technical Reports Server (NTRS)

Critical Areas are defined and discussed in the various areas pertinent to satellite power systems. The presentation is grouped into five areas (General, Space Systems, Solar Energy Conversion, Microwave Systems, and Environment/Ecology) with a sixth area (Power Relay) considered separately in an appendix. Areas for Future Consideration as critical areas are discussed in a second appendix.

1975-01-01

220

A Metric to Evaluate Mobile Satellite Systems  

NASA Technical Reports Server (NTRS)

The concept of a "cost per billable minute" methodology to analyze mobile satellite systems is reviewed. Certain assumptions, notably those about the marketplace and regulatory policies, may need to be revisited. Fading and power control assumptions need to be tested. Overall, the metric would seem to have value in the design phase of a system and for comparisons between and among alternative systems.

Young, Elizabeth L.

1997-01-01

221

Satellite power system salvage and disposal alternatives  

NASA Technical Reports Server (NTRS)

A wide range of salvage options for the SPS satellite, ranging from use in and beyond geosynchronous orbit to use in low Earth orbit in return and use on Earth are presented. The satellite can be used intact to provide power for various purposes, it can be cannibalized or it can be melted down to supply materials for space or ground based products. The use of SPS beyond its nominal lifetime provides value that can be deducted from the SPS capital investment cost. The present value of the salvage value of the SPS satellites, referenced to the system initial operation data, is on the order of five to ten percent of its on-orbit capital cost. (Given a 30 year satellite lifetime and a four percent discount rate, the theoretical maximum salvage value is 30.8 percent of the capital cost.) The SPS demonstration satellite is available some 30 years earlier than the first full scale SPS satellite and has a salvage value on the order of 80 percent of its on-orbit capital cost. In the event that it becomes desirable to dispose of either the demonstration of full scale SPS satellite, a number of disposal options is presented for which intact disposal costs are less than one percent of capital costs.

1980-01-01

222

Instrumentation for Spacecraft-to-Spacecraft Radio Science Observations of Jupiter and Satellites  

Microsoft Academic Search

Investigations of planetary atmospheres and surfaces via radio occultation and scattering techniques have been successfully conducted on many planets and several large satellites in the solar system using one-way downlink from a spacecraft to a ground station. Limitations on the received SNR or geometrical coverage can be overcome with alternate observation configurations. Uplink observations where a signal is transmitted from

Sami Asmar; W. Folkner; D. Hinson; L. Iess; I. Linscott; E. Marouf; P. Tortora

2010-01-01

223

Astrometric observations of the faint satellites of Jupiter during the 1975 - 1976 opposition  

NASA Technical Reports Server (NTRS)

The series of astrometric observations of the satellites of the trans-martian planets re-established at the McDonald Observatory in 1972 is continued. The positions deduced from photographic observations of the jovian system obtained during the 1975-76 opposition are presented together with the discovery positions of four asteroids found on these plates.

Mulholland, J. D.; Shelus, P. J.; Benedict, G. F.

1979-01-01

224

Stratocumulus cloud height variations determined from surface and satellite observations  

NASA Technical Reports Server (NTRS)

Determination of cloud-top heights from satellite-inferred cloud-top temperatures is a relatively straightforward procedure for a well-behaved troposphere. The assumption of a monotonically decreasing temperature with increasing altitude is commonly used to assign a height to a given cloud-top temperature. In the hybrid bispectral threshold method, or HBTM, Minnis et al. (1987) assume that the lapse rate for the troposphere is -6.5/Kkm and that the surface temperature which calibrated this lapse rate is the 24 hour mean of the observed or modeled clear-sky, equivalent blackbody temperature. The International Satellite Cloud Climatology Project (ISCCP) algorithm (Rossow et al., 1988) attempts a more realistic assignment of height by utilizing interpolations of analyzed temperature fields from the National Meteorological Center (NMC) to determine the temperature at a given level over the region of interest. Neither these nor other techniques have been tested to any useful extent. The First ISCCP Regional Experiment (FIRE) Intensive Field Observations (IFO) provide an excellent opportunity to assess satellite-derived cloud height results because of the availability of both direct and indirect cloud-top altitude data of known accuracy. The variations of cloud-top altitude during the Marine Stratocumulus IFO (MSIFO, June 29 to July 19, 1987) derived from surface, aircraft, and satellite data are examined.

Minnis, Patrick; Young, David F.; Davies, R.; Blaskovic, M.; Albrecht, Bruce A.

1990-01-01

225

ECC Ozonesonde Reliability, Observations, and Comparisons with Satellite Ozone Instruments  

NASA Technical Reports Server (NTRS)

Electrochemical Concentration Cell (ECC) ozone instruments depend on the quality of care exercised in their pre-flight preparation. The ozone-measuring project conducted at Goddard Space Flight Center's Wallops Flight Facility uses a number of mechanisms designed to inspect the ECC for anomalies that may interfere with the reception of valid ozone profiles. Complete electronic testing of the instrument, individually and when coupled to its radiosonde has led to exceptional monitoring of ozone for detecting long-term atmospheric changes. A number of factors are considered when preparing an ECC instrument for flight. These basically are specific calibrations of pump efficiency, volumetric flow rate, temperature of the air entering the pump, and background current. The concentration of the potassium iodide solution is also important. Wallops is the only site using a UV photometer (Dasibi) to compare ECC ozone output at various concentrations of ozone that allows adjustment to be made to offsets that may appear in the balloon-borne instrument prior to release. All of the above procedures allow identification of potential problems before release of the ECC instrument. Procedures followed at Wallops also are employed in Brazil, and Ascension Island where NASA has cooperative agreements in place to obtain ozonesondes data. All ECC instruments are prepared 3-4 weeks prior to the day of observation. We will briefly describe the instrumental tests employed. These tests have included simultaneous dual observations to compare the effect of different solution concentrations, comparison of sensors of different manufacturers, and comparisons with surface- and space-based instrumentation such as the Dobson Spectrophotometer and satellites. Vertical profiles of ozone from Arctic, mid-latitudes, and Antarctica will be discussed. Although not unusual, the data reveals ozone structure that correlate well with typical atmospheric temperatures and possibly relative humidity. Finally, vertical ozone distribution, compared with remotely measured ozone from lidar and satellite, will be discussed. Specific comparisons between ECC and HALOE measurements, integrated ECC total ozone overburden with the EP-TOMS and the Dobson, as well as comparisons with lidar are discussed. Results show agreement and some disagreement between the in situ measurements of the ECC and the remote instruments. We postulate reasons for the differences, or biases, which in spite of the excellent ECC quality control during pre-flight preparation and data analysis processes, may be due to uncertainties in both measuring systems.

Schmidlin, F. J.; Northam, E. T.; Ross, E. D.; Schauer, A. G.; Gerlach, John C. (Technical Monitor)

2001-01-01

226

Appropriate satellite systems for rural telecommunications  

NASA Astrophysics Data System (ADS)

In order to provide a minimum, basic telecommunications service to as large a segment of the unserved rural population as possible, the system objective should be to place one or a few telephone instruments in as many localities as possible, instead of placing a larger number of subscriber instruments in fewer localities. A high value of satellite figure of merit (G/T) combined with high transponder gain would facilitate the utilization of low transmit power from the earth station; it is claimed that this would be the key to the success of an operational rural telecommunications service via satellite. It is noted that demand assigned SCPC transmission techniques are ideally suited for this service. It is concluded that, for satellite communications to provide minimum basic rural telephone service within a reasonable time span, it will be necessary to employ properly designed high-transfer-gain satellites with large production runs of small low-cost earth stations.

Nickelson, R. L.

227

Land-mobile satellite communication system  

NASA Technical Reports Server (NTRS)

A satellite communications system includes an orbiting communications satellite for relaying communications to and from a plurality of ground stations, and a network management center for making connections via the satellite between the ground stations in response to connection requests received via the satellite from the ground stations, the network management center being configured to provide both open-end service and closed-end service. The network management center of one embodiment is configured to provides both types of service according to a predefined channel access protocol that enables the ground stations to request the type of service desired. The channel access protocol may be configured to adaptively allocate channels to open-end service and closed-end service according to changes in the traffic pattern and include a free-access tree algorithm that coordinates collision resolution among the ground stations.

Yan, Tsun-Yee (Inventor); Rafferty, William (Inventor); Dessouky, Khaled I. (Inventor); Wang, Charles C. (Inventor); Cheng, Unjeng (Inventor)

1993-01-01

228

Observing system simulation experiments to evaluate the expected added-value of a new generation IASI satellite instrument for lower tropospheric ozone analyses and forecasts  

NASA Astrophysics Data System (ADS)

Tropospheric ozone can adversely impact human health, climate and the ecosystem. Monitoring and legislation are implemented to regulate its concentrations. Air quality (AQ) monitoring from space starts to be regarded as a useful tool to complement with in situ measurements and regional chemical transport models (rCTM) to draw a more comprehensive picture of pollution processes. Important progresses in the field of tropospheric ozone sounding from space have been accomplished during the last decade, especially with thermal infrared (TIR) space-borne instruments. It is now possible to observe tropospheric ozone concentrations from space with a reasonable accuracy. However, limitations remain with the current observation systems in particular to observe ozone in the lowermost troposphere. IASI-NG, that will be part of the EPS-SG (EUMETSAT Polar System-Second Generation) programme, is expected to improve the observation capabilities of AQ in terms of ozone in the lower troposphere. Observing system simulation experiments (OSSEs) are powerful tools to quantify the added-value of future missions. An OSSE is composed of different elements: (1) one reference atmosphere, usually given by model simulations (the Nature Run); (2) an optimized observation simulator, providing the pseudo-observations; (3) an independent description of the atmosphere (the Control Run); (4) an assimilation system, providing the Assimilation Run. We conduct relative OSSEs, aimed at comparing the contribution of one possible configuration of IASI-NG (IASI-NG/IRS2) and the present IASI instrument, used as a baseline. The spectral resolution and the radiometric noise in the ozone spectral region, for IASI-NG/IRS2, are twice better than for IASI. IASI-NG/IRS2 pseudo-observations are processed using a comprehensive simulator based on the radiative transfer model KOPRA and the KOPRAFIT inversion module. The Nature Run is given by the CTM MOCAGE model, the Control Run is produced with the CHIMERE CTM, and the assimilation system is based on a Local Ensemble Kalman Filter. The objective is to assess the potential improvement bring by IASI-NG compared to IASI to constrain model simulations. The gain of these new observations to improve ozone analysis (and forecast) are quantified especially in the planetary boundary layer for the European domain.

Dauphin, Pierre; Sellitto, Pasquale; Dufour, Gaëlle; Coman, Adriana; Forêt, Gilles; Eremenko, Maxim; Cuesta, Juan; Gaubert, Benjamin; Beekmann, Matthias; Peuch, Vincent-Henri; Flaud, Jean-Marie

2013-04-01

229

Orbit determination accuracies using satellite-to-satellite tracking. [applicable to the Tracking and Data Relay Satellite system  

NASA Technical Reports Server (NTRS)

The results of the ATS-6/GEOS-3 and the ATS-6/NIMBUS-6 satellite-to-satellite tracking orbit determination experiments are reported. The tracking systems used in these experiments differ from the Tracking and Data Relay Satellite System (TDRSS), primarily in the use of one rather than two synchronous relay satellites. However, the simulations mentioned indicate that the insights gained from the experiments with regard to proper data reduction techniques and expected results are applicable to the TDRSS.

Vonbun, F. O.; Argentiero, P. D.; Schmid, P. E.

1978-01-01

230

Satellite-Observed Intensification of the Tropical Atmospheric Circulation  

NASA Astrophysics Data System (ADS)

Observational climate records from satellite measurements continue to grow in length and improve in accuracy. Here we will present an analysis of a 25-year satellite data record for geophysical variables over the ocean related to the atmospheric circulation and the hydrological cycle: surface winds, tropospheric temperatures, precipitation rate, total columnar water vapor, and total cloud water. Observed wind speed trend patterns suggest an intensification of the Tropical atmospheric circulation, in terms of the Pacific Walker cell. Precipitation trends suggest and intensification of the hydrological cycle at a rate comparable to the rate of water vapor increase. This precipitation increase is inconsistent with a weakening of the atmospheric circulation which some atmospheric models predict as a result of global warming. Water vapor trend patterns suggest an intensification of the Hadley cell. In the tropical regions, these 25-yr trends are substantially greater than the observational uncertainty, therefore they are statistically significant. All these results are portraying a consistent picture of an intensified Tropical atmospheric circulation and hydrological cycle in the past 25 years. Because of the limited length of the satellite data record, it may not be possible to attribute these trends to decadal changes due to anthropogenic forcing. Alternatively, they might be the signature of ENSO variability in the past 25 years, or of the Pacific Decadal Oscillation. More analysis is needed to determine the contribution of these oscillations to the observed trends. However, the satellite observed trends highlight a discrepancy with model predicted decadal changes to the hydrological cycle and the Walker circulation. Climate model simulations do not show any significant wind trend over a 25-year period, and they predict a much smaller intensification of the hydrological cycle. These discrepancies must be resolved in order to increase confidence in climate model predictions.

Ricciardulli, L.; Wentz, F. J.; Mears, C. A.

2012-12-01

231

Solar power satellite, system definition study. Part 2, volume 3: SPS satellite systems  

NASA Technical Reports Server (NTRS)

The differences in approach to solar energy conversion by solar cells and thermal engine systems are examined. Systems requirements for the solar power satellite (SPS) are given along with a description of the primary subsystems. Trades leading to exact configuration selection, for example, selection of the Rankine cycle operating temperatures are explained, and two satellite configurations are discussed.

1977-01-01

232

Ground-based observations coordinated with Viking satellite measurements  

NASA Astrophysics Data System (ADS)

Results are presented from a program of observations from stations in northern Scandinavia coordinated with observations made with the Swedish satellite Viking. The observations are used to study substorm expansion, focusing on the end of a substorm and the associated decay of a westward-travelling surge. The ionospheric conductivities, electric fields, and neutral winds associated with substorm auroras are examined, using Eiscat measuremnets. It is found that the conductivities and electric fields associated with westward-travelling surges are incorrectly represented by existing models.

Opgenoorth, H. J.; Kirkwood, Sheila

233

Satellite reconnaissance  

NASA Astrophysics Data System (ADS)

The potential of the observation equipment in remote sensing satellites is described. United States meteorology, land use and oceanography satellites and the major US Earth observation programs are listed. Imaging satellite systems are described such as: visible light and near infrared, thermal IR window, and microwave window. It is concluded that a geometrical resolution between 10 and 40 m can be expected. In order to reduce the data flow from the satellite system the input side of the system (the object-sensor interaction) has to be known. Satellites with synthetic aperture radar are increasingly important, but satellites can never fully replace observations with aircraft and drones.

Deloor, G. P.

1984-06-01

234

Applications of neural network methods to the processing of earth observation satellite data.  

PubMed

The new generation of earth observation satellites carries advanced sensors that will gather very precise data for studying the Earth system and global climate. This paper shows that neural network methods can be successfully used for solving forward and inverse remote sensing problems, providing both accurate and fast solutions. Two examples of multi-neural network systems for the determination of cloud properties and for the retrieval of total columns of ozone using satellite data are presented. The developed algorithms based on multi-neural network are currently being used for the operational processing of European atmospheric satellite sensors and will play a key role in related satellite missions planed for the near future. PMID:16530385

Loyola, Diego G

2006-03-01

235

Evaluation of NWP Cloud Properties using A-Train Satellite Observations  

NASA Astrophysics Data System (ADS)

The goal of this study is to present results from our ongoing research that is focused on developing satellite diagnostic tools for the evaluation of NWP model forecasts of cloud macro properties (e.g., cloud type height, cloud type, horizontal and vertical structure, location, etc.) using high resolution A-Train (e.g., CloudSat, CALIPSO, MODIS, etc.) and other satellite observations. The satellite diagnostic tools have been incorporated into the NCAR Model Evaluation Toolkit (MET). The tools have the capability of ingesting A-Train satellite observations into a framework for comparisons with model products and other satellite datasets. We are currently applying the MET tool to provide assessment of forecasted cloud properties ranging from large scale stratiform systems to deep convective storms. We are evaluating the capability of NWP models to predict clouds for a variety of conditions (complex terrain, land/water, and seasonal dependency). The outcome of the analysis is to provide feedback to model developers in an effort to improve NWP models capabilities to forecast representative cloud features. We recently applied the satellite diagnostics tools to winter time forecasting experiment that was conducted in the US. The presentation will give a summary of the wintertime experiment and provide an overview of the satellite diagnostic methods developed in MET. We will also highlight some of the results obtained from our cloud climatology-NWP evaluation analysis.

Kucera, Paul; Weeks, Courtney; Brown, Barbara; Bullock, Randy

2013-04-01

236

Meteosat Third Generation (MTG) Development in the Context of Other Future Geostationary Satellite Observations  

NASA Astrophysics Data System (ADS)

Meteosat Third Generation (MTG) will provide continuity to the European Meteosat observations which are currently performed with Meteosat Second Generation (MSG). MSG takes images in 12 channels with a repeat rate of 15 minutes for the full disk. The future MTG satellites will expand the capabilities far beyond those of MSG with an enhanced imager (FCI) which has 16 channels and a 10 minutes repeat cycle for taking images of the earth's full disk. Especially the novel instruments on MTG a) Lightning Imager (LI), hyperspectral InfraRed Sounder (IRS) and the Ultraviolet-Visible-Near infrared spectrometer (UVN) will provide unprecedented observations. The four instruments will fly on two types of satellites, the imaging satellites (MTG-I) carrying the FCI and LI, and the sounding satellites (MTG-S) carrying the IRS and UVN. The UVN instrument is provided by the European Space Agency (ESA) and the European GMES (Global Monitoring and Environmental Security) programme. The first launch of an imaging satellite is foreseen for 2017. In total the MTG series will serve us with four MTG-I and two MTG-S satellites for about two decades. MTG has been defined to meet the requirements of the user community, i.e. mainly users in Europe. However an interesting perspective is to see the development of the European MTG satellite system in the context of the evolution of the global space-based meteorological satellite system, notably those from geostationary orbit. Satellite agencies in the US, Japan, China and Europe will fly advanced imagers comparable to the FCI on MTG. Therefore there is also scope for a common evolution of the applications of the observations which is being addressed inter alia by CGMS (Coordination Group for Meteorological Satellites). Various agencies will also realise lightning observations from space. Other instruments on MTG (IRS and UVN) can be seen as pioneering realisations in a geostationary orbit of measurements known from polar orbits. This step into the geostationary orbit will enable a high temporal repeat cycle of the observations. For water vapour this means that for the first time observations from space are being made with a temporal resolution commensurate with the spatial resolution. The presentation will present the status of the instrument and applications development. It will also highlight the current cooperation opportunities created by the similarity of the future observing systems.

Schmetz, J.; Stuhlmann, R.; Grandell, J.; Tjemkes, S.; Calbet, X.; Koenig, M.; Rota, S.

2012-12-01

237

Satellite sound broadcasting system study: Mobile considerations  

Microsoft Academic Search

Discussed here is the mobile reception part of a study to investigate a satellite sound broadcast system in the UHF or L bands. Existing propagation and reception measurements are used with proper interpretation to evaluate the signaling, coding, and diversity alternatives suitable for the system. Signal attenuation in streets shadowed by buildings appear to be around 29 db, considerably higher

Nasser Golshan

1990-01-01

238

Health Monitoring of a Satellite System  

NASA Technical Reports Server (NTRS)

A health monitoring system based on analytical redundancy is developed for satellites on elliptical orbits. First, the dynamics of the satellite including orbital mechanics and attitude dynamics is modelled as a periodic system. Then, periodic fault detection filters are designed to detect and identify the satellite's actuator and sensor faults. In addition, parity equations are constructed using the algebraic redundant relationship among the actuators and sensors. Furthermore, a residual processor is designed to generate the probability of each of the actuator and sensor faults by using a sequential probability test. Finally, the health monitoring system, consisting of periodic fault detection lters, parity equations and residual processor, is evaluated in the simulation in the presence of disturbances and uncertainty.

Chen, Robert H.; Ng, Hok K.; Speyer, Jason L.; Guntur, Lokeshkumar S.; Carpenter, Russell

2004-01-01

239

Data distribution satellite system architecture concept  

NASA Technical Reports Server (NTRS)

This paper describes a future communications satellite system architecture concept called the Data Distribution Satellite (DDS). The DDS is envisioned as a new system to be used as an adjunct to TDRS/TDAS for distributing new NASA science data throughout the U.S. as well as internationally. The DDS would also provide networking capability for interchange of science database files among science users and NASA archive depositories. Experimenters would be able to access and control their experimental packages remotely, relieving astronaut workload. This paper gives a conceptual system design based on year 1995 technology. Features of the design include use of Ku and Ka-bands, use of fixed spot beams, 2 Gb/s throughput, and on-board demodulation and switching. The satellite dry mass is 1,300 kg and end-of-life power is 4 kW.

Price, Kent M.; Jorasch, Ronald E.

1990-01-01

240

An advanced domestic satellite communications system  

NASA Technical Reports Server (NTRS)

An updated traffic projection for U.S. domestic satellite communications service covering a period of 15 years; mid-1980 to mid-1995 was prepared. This model takes into account expected technology advances and reductions in transmission costs, legislative and regulatory changes permitting increased competition, and rising energy costs which will encourage more extensive substitution of telecommunications for travel. The historical development and current status of satellite systems are discussed as well as the characteristics of follow-on systems. Orbital arc utilization, spacecraft configuration for single shuttle launch, Earth station configuration, and system costs are examined. Areas which require technology development include multiple beam frequency reuse antennas, on-board switching, intersatellite links, and ka-band operation. Packing and deployment schemes for enclosing the satellite within the shuttle orbiter bay must also be devised.

1980-01-01

241

Evaluation of Modeled Clouds using the Satellite Observations  

NASA Astrophysics Data System (ADS)

The merged CloudSat and CALIPSO data streams provide the first global survey of the vertical distribution of cloud condensate and precipitation. We exploit the synergy of the "A-Train", a constellation of satellites flying in formation, to deliver complementary measurements of the same environmental phenomena and the collocated large scale variables along the CloudSat flight track to further understand model deficiencies. The NCAR's Community Atmosphere Model (CAM4 for IPCC integrations) are evaluated. To make the comparison between model output and observations in a more consistent manner, the CFMIP Observation Simulator Package (COSP) is applied to the model output. The COSP converts model clouds into pseudosatellite observations with a model to satellite approach that mimics the satellite view of an atmospheric column with model specified physical properties. The COSP output from the simulators of multiple sensors are compared with model output. This work was performed under the auspices of the U. S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344.

Zhang, Y.; Klein, S. A.; Boyle, J. S.; Kay, J. E.; Mace, G. G.

2010-12-01

242

Satellite Diversity Gain Over The LEOS Channel, Based CDMA Systems  

E-print Network

proposed as the multiple access technique for a number of mobile satellite communication systemsSatellite Diversity Gain Over The LEOS Channel, Based CDMA Systems Tarek Attia, Peter Sweeney: There is a trend for mobile satellite system architectures aimed at the deployment of multi-satellite

Haddadi, Hamed

243

Satellite Power System (SPS) public outreach experiment  

NASA Technical Reports Server (NTRS)

An outreach experiment was conducted to improve the results of the satellite power system (SPS) concept development and evaluation program. The objectives of the outreach were to: (1) determine the areas of major concern relative to the SPS concept and (2) gain experience with an outreach process for use in future public involvement. The response to the outreach effort was positive, suggesting that the effort extended by the SPS project division to encourage an information exchange with the public was well received. The responses were analyzed and from them some questions and answers about the satellite power system are presented.

Mcneal, S. R.

1980-01-01

244

The United States regional mobile satellite system  

NASA Astrophysics Data System (ADS)

Commercial interests within the United States and Canada are preparing to implement cooperative systems that will provide land and aeronautical mobile satellite services in those two countries and in Mexico. Wide bandwidth, linear satellites ('bent pipe transponders') in geostationary orbit will be built and operated by a consortium of companies in the United States. The consortium will act as a carrier's carrier, leasing bandwidth and power to resellers and private radio leasees who will tailor the ground systems and signal characteristics to the needs of end users. A variety of voice, data, and position fixing services will add new dimensions to mobile communications throughout North America.

Anderson, Roy E.; Cooperman, Richard S.

245

Long-Focus Astrometric Observations of the Planetary Satellites at USNO: 1967 2003  

E-print Network

59 Long-Focus Astrometric Observations of the Planetary Satellites at USNO: 1967 ­ 2003 Dan Pascu of long- focus observations of the planetary satellites made at the U.S. Naval Observatory (USNO) from refractor, targeted the Martian satellites, the Galilean moons of Jupiter and satellites I ­ VIII of Saturn

Paris-Sud XI, Université de

246

Planning for Agile Earth Observation Satellites Johannes Aldinger and Johannes Lohr  

E-print Network

Planning for Agile Earth Observation Satellites Johannes Aldinger and Johannes L¨ohr Albert}@informatik.uni-freiburg.de Abstract Agile Earth observation satellites are satellites orbiting Earth with the purpose to gather information of the Earth's surface by slewing the satellite toward regions of interest. Constraints arise

Nebel, Bernhard

247

The investigation of tethered satellite system dynamics  

NASA Technical Reports Server (NTRS)

Progress in tethered satellite system dynamics research is reported. A retrieval rate control law with no angular feedback to investigate the system's dynamic response was studied. The initial conditions for the computer code which simulates the satellite's rotational dynamics were extended to a generic orbit. The model of the satellite thrusters was modified to simulate a pulsed thrust, by making the SKYHOOK integrator suitable for dealing with delta functions without loosing computational efficiency. Tether breaks were simulated with the high resolution computer code SLACK3. Shuttle's maneuvers were tested. The electric potential around a severed conductive tether with insulator, in the case of a tether breakage at 20 km from the Shuttle, was computed. The electrodynamic hazards due to the breakage of the TSS electrodynamic tether in a plasma are evaluated.

Lorenzini, E.

1985-01-01

248

The 'Geostar' radio determination satellite system  

NASA Astrophysics Data System (ADS)

The proposed Geostar system which links portable and mobile terminals directly through satellite relays to a ground-based computer is capable of providing the following services in a variety of transportation modes: (1) navigational positioning, (2) terrain warning to pilots and hazard warning to mariners, (3) approach guidance for aircraft and (4) two-way digital message service. Able to operate in a supplementary or advisory mode, the Geostar system combines the existing technologies of orbital satellites, computers and integrated circuits. It consists of the following: (1) a ground station with a computer, two or more satellites at fixed locations in earth orbit, and terminals carried by aircraft, surface vehicles, etc. Geostar's practical implications are discussed as well as the fitting of its necessary radio frequencies in the ITU table of allocations.

Oneill, G. K.

1986-05-01

249

A Comparison of Techniques for Scheduling Earth-Observing Satellites  

NASA Technical Reports Server (NTRS)

Scheduling observations by coordinated fleets of Earth Observing Satellites (EOS) involves large search spaces, complex constraints and poorly understood bottlenecks, conditions where evolutionary and related algorithms are often effective. However, there are many such algorithms and the best one to use is not clear. Here we compare multiple variants of the genetic algorithm: stochastic hill climbing, simulated annealing, squeaky wheel optimization and iterated sampling on ten realistically-sized EOS scheduling problems. Schedules are represented by a permutation (non-temperal ordering) of the observation requests. A simple deterministic scheduler assigns times and resources to each observation request in the order indicated by the permutation, discarding those that violate the constraints created by previously scheduled observations. Simulated annealing performs best. Random mutation outperform a more 'intelligent' mutator. Furthermore, the best mutator, by a small margin, was a novel approach we call temperature dependent random sampling that makes large changes in the early stages of evolution and smaller changes towards the end of search.

Globus, Al; Crawford, James; Lohn, Jason; Pryor, Anna

2004-01-01

250

Low-power magnetometer observation with satellite data transmission at unmanned site in Antarctica  

NASA Astrophysics Data System (ADS)

We will report technical experiences from 6 years of unmanned low power magnetometer observation in Antarctica with daily data transmission via Iridium satellite telephone link. One of the difficulties of unmanned observation in Antarctica is dark winter months in which power supply from solar panel can not be expected. One solution for this difficulty is to minimize the power consumption (as small as ~1 W) to manage the observation in winter months with limited amount of batteries (~400Ah). Another difficulty is to collect data from the observation site. It is quite expensive and laborious to send a party to the observation site to obtain the data in Antarctica. Although cost for satellite communication is expensive, it is much more economical to collect data via satellite data link by installing a telephone terminal into the observation system. It seems that power consumption of a satellite phone (~10 W) does not fit to the low power system. However, as long as the observed data is not too large (<1 Mbyte per day), turn on period of the satellite phone is short (<1 hour per day) and the daily average of total power consumption lies within the available power of ~1 W. We have developed low-power magnetometer system with Iridium satellite phone data link. Basic design of the low-power system is similar to that developed by British Antarctic Survey (intermittent operation of magnetometer and GPS). However, we have made some improvements; reduced power consumption (0.2 W) at high sampling rate (1Hz) and increased sensitivity (0.2nT), so that geomagnetic pulsation study can be possible. In our observation system, satellite data transfer is only made in sunlit season with the total power consumption of 1 W (0.8W for Iridium phone and 0.2W for others). During dark winter months, observed data are stored in CF memory with diminished power consumption of 0.2W. When the sun comes in spring, the stored data are transmitted along with the daily observed data. It takes nearly two months to complete the transmission of data stored in winter months. We have installed two sets of low-power magnetometer at inland and coastal area in January, 2007. We added one set every austral summer and, by January 2010, 5 magnetometers are deployed within a radius of 700km from Syowa Station. The observed data can be used for the study of magnetic pulsations, as well as small and medium scale structure of ionospheric currents at the time of auroral substorm.

Yamagishi, H.; Kadokura, A.

2012-12-01

251

Satellite observations of air quality of megacities in China  

NASA Astrophysics Data System (ADS)

In the last three decades, air pollution has become a major environmental issue in metropolitan areas of China as a consequence of fast industrialization and urbanization, and the rapid increase of the vehicle ownership. Now in China there are 3 megacities (Beijing, Shanghai and Guangzhou) in existence. A recent study of Asian megacities showed that they cover less than 2% of the land area, hold more than 30% of the population and produce about 10% of the anthropogenic gas and aerosol emissions. Therefore, it is important to qualify and understand current air pollution distribution and development in and around the megacities of China. Satellite observations provide unique insight into the regional air quality around megacities and air pollution transport from surrounding areas. In this work, we present an investigation of air quality over Beijing, Shanghai and Guangzhou combining satellite and ground-based measurements. Aerosol optical thickness (AOT), precursors of ozone (notably NO2 and CH2O), and SO2 are observed from space. The operational GOME-2 trace gases products developed at German Aerospace Center and MODIS AOT products will be used. Moreover, near surface concentrations of particular matter (PM), NO2 and SO2 in Beijing, Shanghai and Guangzhou are investigated. The effect of air pollution transport from neighboring areas to megacities will be researched using satellite measurements. Initial comparison between satellite and ground-based measurements of air pollutants in Beijing, Shanghai and Guangzhou will be shown. We will present the relationship between AOT and PM concentrations in megacities. The use of AOT, tropospheric NO2 and CH2O columns for air quality applications will also be shown.

Hao, N.; Valks, P.; Smedt, I. D.; Loyola, D.; Roozendael, M. V.; Zhou, B.; Zimmer, W.

2012-04-01

252

A native IP satellite communications system  

NASA Astrophysics Data System (ADS)

? In the framework of ESA's ARTES-5 program the Institute of Applied Systems Technology (Joanneum Research) in cooperation with the Department of Communications and Wave Propagation has developed a novel meshed satellite communications system which is optimised for Internet traffic and applications (L*IP—Local Network Interconnection via Satellite Systems Using the IP Protocol Suite). Both symmetrical and asymmetrical connections are supported. Bandwidth on demand and guaranteed quality of service are key features of the system. A novel multi-frequency TDMA access scheme utilises efficient methods of IP encapsulation. In contrast to other solutions it avoids legacy transport network techniques. While the DVB-RCS standard is based on ATM or MPEG transport cells, the solution of the L*IP system uses variable-length cells which reduces the overhead significantly. A flexible and programmable platform based on Linux machines was chosen to allow the easy implementation and adaptation to different standards. This offers the possibility to apply the system not only to satellite communications, but provides seamless integration with terrestrial fixed broadcast wireless access systems. The platform is also an ideal test-bed for a variety of interactive broadband communications systems. The paper describes the system architecture and the key features of the system.

Koudelka, O.; Schmidt, M.; Ebert, J.; Schlemmer, H.; Kastner-Puschl, S.; Riedler, W.

2004-08-01

253

PHEMU 2003 campaign: observations of the mutual phenomena of the Galilean satellites in Romania  

NASA Astrophysics Data System (ADS)

We present CCD, photoelectric, and video observations of selected mutual phenomena of the Galilean satellites. The campaign was carried out in Bucharest and Cluj-Napoca as part of the PHEMU2003 international effort. Five different optical systems were used for data acquisition. Here we report the observational results obtained in acceptable meteorological conditions for twenty mutual phenomena, nine eclipses, and eleven occultations. A preliminary analysis of the observations estimates the accuracy of the data.

Arlot, J.-E.; Chis, G.-D.; Farkas, L.; Moldovan, D.; Nedelcu, A.; Popescu, P.; Sorescu, S.; Stavinschi, M.; Serbanescu, L.; Tudose, V.; Turcu, V.

2005-08-01

254

Spread spectrum synchronization for a LEO personal communications satellite system  

Microsoft Academic Search

This paper investigates required signal structure and receiver code synchronization techniques for satellite based CDMA personal communications systems. A signal structure is proposed in which different CDMA codes are used to differentiate each satellite (as in the GPS system) and different phases of one code (as in the IS-95 standard) to differentiate spot beams on one satellite. Due to satellite

D. E. Dodds; M. Moher

1995-01-01

255

Satellite Power System (SPS) military implications  

NASA Technical Reports Server (NTRS)

The military implications of the reference satellite power system (SPS) were examined is well as important military related study tasks. Primary areas of investigation were the potential of the SPS as a weapon, for supporting U.S. military preparedness, and for affecting international relations. In addition, the SPS's relative vulnerability to overt military action, terrorist attacks, and sabotage was considered.

Bain, C. N.

1978-01-01

256

Satellite Power System (SPS) military applications  

NASA Technical Reports Server (NTRS)

The potential military role, both offensive and defensive, of a Satellite Power System (SPS) is examined. A number of potential military support possibilities are described. An SPS with military capabilities may have a strong negative impact on international relations if it is not internationalized. The SPS satellite would be vulnerable to military action of an enemy with good space capability, but would experience little or no threat from saboteurs or terrorists, except via the ground controls. The paper concludes with an outline of some of the key issues involved, and a number of recommendations for future study, including some areas for long term efforts.

Ozeroff, M. J.

1978-01-01

257

Applications systems verification and transfer project. Volume 7: Cost/benefit analysis for the ASVT on operational applications of satellite snow-cover observations  

NASA Technical Reports Server (NTRS)

The results of the OASSO ASVT's were used to estimate the benefits accruing from the added information available from satellite snowcover area measurement. Estimates of the improvement in runoff prediction due to addition of SATSCAM were made by the Colorado ASVT personnel. The improvement estimate is 6-10%. Data were applied to subregions covering the Western States snow area amended by information from the ASVT and other watershed experts to exclude areas which are not impacted by snowmelt runoff. Benefit models were developed for irrigation and hydroenergy uses. The benefit/cost ratio is 72:1. Since only two major benefit contributors were used and since the forecast improvement estimate does not take into account future satellite capabilities these estimates are considered to be conservative. The large magnitude of the benefit/cost ratio supports the utility and applicability of SATSCAM.

Castruccio, P.; Loats, H.; Lloyd, D.; Newman, P.

1981-01-01

258

An automated mapping satellite system ( Mapsat).  

USGS Publications Warehouse

The favorable environment of space permits a satellite to orbit the Earth with very high stability as long as no local perturbing forces are involved. Solid-state linear-array sensors have no moving parts and create no perturbing force on the satellite. Digital data from highly stabilized stereo linear arrays are amenable to simplified processing to produce both planimetric imagery and elevation data. A satellite imaging system, called Mapsat, including this concept has been proposed to produce data from which automated mapping in near real time can be accomplished. Image maps as large as 1:50 000 scale with contours as close as a 20-m interval may be produced from Mapsat data. -from Author

Colvocoresses, A.P.

1982-01-01

259

Contributions of Satellite Observations to Understanding Climate Change  

NASA Technical Reports Server (NTRS)

One of the challenges facing atmospheric scientists is to interpret trends in multi-decadal data records. Although data records from satellite instruments are not as long as some ground-based records, global coverage and resolved vertical profiles provide unique information for identifying signatures of climate change. For example, the Halogen Occultation Experiment (HALOE) on the Upper Atmosphere Research Satellite provided profiles of O3, H2O, HC1, HF, CH4 from October 1991 until November 2005. There are also multi-annual ground based measurements of the column HCl. Middle latitude ground-based measurements show a seasonal cycle, and the HALOE profiles show that this is driven by the seasonal change in the composition and mass of the region between the tropopause and 380K surface (the lowermost stratosphere). Understanding the processes that produce the seasonal cycle makes it possible to interpret a future change in the seasonal cycle as a marker of a change in the stratospheric residual circulation. Satellite observations have also provided key information for improving the physical basis of models used to predict future composition and climate circulation. An example is the "tape recorder" signature in tropical stratospheric water vapor, i.e., the slow ascent of high and low water vapor anomalies roughly corresponding to the tropopause temperature at the time air entered the stratosphere. This signature has become a key diagnostic of performance for climate models.

Douglass, Anne R.

2006-01-01

260

Comparing soil moisture memory in satellite observations and models  

NASA Astrophysics Data System (ADS)

A major obstacle to a correct parametrization of soil processes in large scale global land surface models is the lack of long term soil moisture observations for large parts of the globe. Currently, a compilation of soil moisture data derived from a range of satellites is released by the ESA Climate Change Initiative (ECV_SM). Comprising the period from 1978 until 2010, it provides the opportunity to compute climatological relevant statistics on a quasi-global scale and to compare these to the output of climate models. Our study is focused on the investigation of soil moisture memory in satellite observations and models. As a proxy for memory we compute the autocorrelation length (ACL) of the available satellite data and the uppermost soil layer of the models. Additional to the ECV_SM data, AMSR-E soil moisture is used as observational estimate. Simulated soil moisture fields are taken from ERA-Interim reanalysis and generated with the land surface model JSBACH, which was driven with quasi-observational meteorological forcing data. The satellite data show ACLs between one week and one month for the greater part of the land surface while the models simulate a longer memory of up to two months. Some pattern are similar in models and observations, e.g. a longer memory in the Sahel Zone and the Arabian Peninsula, but the models are not able to reproduce regions with a very short ACL of just a few days. If the long term seasonality is subtracted from the data the memory is strongly shortened, indicating the importance of seasonal variations for the memory in most regions. Furthermore, we analyze the change of soil moisture memory in the different soil layers of the models to investigate to which extent the surface soil moisture includes information about the whole soil column. A first analysis reveals that the ACL is increasing for deeper layers. However, its increase is stronger in the soil moisture anomaly than in its absolute values and the first even exceeds the latter in the deepest layer. From this we conclude that the seasonal soil moisture variations dominate the memory close to the surface but these are dampened in lower layers where the memory is mainly affected by longer term variations.

Stacke, Tobias; Hagemann, Stefan; Loew, Alexander

2013-04-01

261

Fast Emission Estimates in China Constrained by Satellite Observations (Invited)  

NASA Astrophysics Data System (ADS)

Emission inventories of air pollutants are crucial information for policy makers and form important input data for air quality models. Unfortunately, bottom-up emission inventories, compiled from large quantities of statistical data, are easily outdated for an emerging economy such as China, where rapid economic growth changes emissions accordingly. Alternatively, top-down emission estimates from satellite observations of air constituents have important advantages of being spatial consistent, having high temporal resolution, and enabling emission updates shortly after the satellite data become available. Constraining emissions from concentration measurements is, however, computationally challenging. Within the GlobEmission project of the European Space Agency (ESA) a new algorithm has been developed, specifically designed for fast daily emission estimates of short-lived atmospheric species on a mesoscopic scale (0.25 × 0.25 degree) from satellite observations of column concentrations. The algorithm needs only one forward model run from a chemical transport model to calculate the sensitivity of concentration to emission, using trajectory analysis to account for transport away from the source. By using a Kalman filter in the inverse step, optimal use of the a priori knowledge and the newly observed data is made. We apply the algorithm for NOx emission estimates in East China, using the CHIMERE model together with tropospheric NO2 column retrievals of the OMI and GOME-2 satellite instruments. The observations are used to construct a monthly emission time series, which reveal important emission trends such as the emission reduction measures during the Beijing Olympic Games, and the impact and recovery from the global economic crisis. The algorithm is also able to detect emerging sources (e.g. new power plants) and improve emission information for areas where proxy data are not or badly known (e.g. shipping emissions). The new emission estimates result in a better agreement between observations and simulations of air pollutant concentrations, facilitating improved air quality forecasts. The EU project MarcoPolo will combine these emission estimates from space with statistical information on e.g. land use, population density and traffic to construct a new up-to-date emission inventory for China.

Mijling, B.; van der A, R.

2013-12-01

262

Satellite-based Observation of the Tectonics of Southern Tibet  

SciTech Connect

The Himalayas and the Tibetan Plateau were formed as a result of the collision of India and Asia, and provide an excellent natural laboratory for the investigation of the mechanical response of the outer 100 km of the Earth (the lithosphere) to tectonic stress. Geophysicists are divided in their views on the nature of this response with one group advocating homogeneously distributed deformation in which the lithosphere deforms as a fluid continuum while others contend that deformation is highly localized with the lithosphere deforming as a system of rigid blocks. These rigid blocks or plate undergo little internal deformation. The latter group draws support from the high slip-rates recently observed on strike-slip faults along the northern edge of the Plateau (the Altyn Tagh Fault, ATF), coupled with seismic observations suggesting that these faults penetrate the entire lithosphere. These ''lithospheric faults'' define continental lithospheric plates and facilitate the eastward extrusion of the ''central Tibet plate''. If extrusion of a rigid Tibet occurs then there must be equivalent features at its southern boundary with slip-rates similar to those in the north. The southern boundary of Tibet, defined by the Main Himalayan Thrust (MHT), has no lateral component of motion and is therefore kinematically incompatible with motion in the north. However, a series of features, the Karakorum Fault, the Karakorum-Jiali Fracture Zone (KJFZ), the Jiali Fault and the Red River Fault which lie to the north of the MHT may define the actual, kinematic, southern boundary of this ''central Tibet plate''. We have investigated the rate of slip along the Karakorum Fault (KKF), the major strike-slip fault in southwestern Tibet. If the KKF represents the actual, kinematic, southern boundary of this Tibet, and is the only feature accommodating eastward extrusion of Tibet, then its slip-rate should be similar to that of the ATF in the north. Offsets along the Karakorum Fault ranging from tens of meters to kilometers have been mapped using satellite imagery and field mapping, and samples ages determined by cosmic-ray exposure dating. Near Bulong Kol (39{sup o}N, 75{sup o}E) cosmogenic dating of a 40 m fluvial offset yields a slip rate of {approx}6.5 mm/yr. Near Mt. Kailas (31.5{sup o}N, 80.7{sup o}E), a glacial moraine offset by {approx}350 m has been dated at 32.3 {+-} 9.5 thousand years, yielding a slip rate of 10.8 {+-} 3.6 mm/yr. In the Gar Valley (32{sup o}N, 80{sup o}E) a river channel incised in glacial sediments yields an offset of 1750 m and an age of 283,000 years equivalent to a slip-rate of 6 mm/yr. Relative to the ATF, the slip rates on the KKF are lower than expected, and since these measurements cover almost the entire length of the KKF, the disparity cannot be attributed to along strike variation in the rate. Based upon the analysis of satellite images along the Karakorum Fault, we believe that this apparent slip deficit may be to the en echelon arrangement of multiple strike slip fault segments that characterize what should more appropriately be called the Karakorum Fault Zone. The geometric arrangement of parallel fault segments produces the ''pull apart'' basins that form the valleys along the KKF. Hence, at any given latitude, slip along the KKF may be distributed among numerous fault segments. This investigation supports efforts to understand the structure and mechanical response of the Earth's crust and supports the application of remote sensing methods.

Ryerson, F J; Finkel, R; van der Woerd, J

2003-02-06

263

Observations on Complexity and Costs for Over Three Decades of Communications Satellites  

NASA Astrophysics Data System (ADS)

This paper takes an objective look at approximately thirty communications satellites built over three decades using a complexity index as an economic model. The complexity index is derived from a number of technical parameters including dry mass, end-of-life- power, payload type, communication bands, spacecraft lifetime, and attitude control approach. Complexity is then plotted versus total satellite cost and development time (defined as contract start to first launch). A comparison of the relative cost and development time for various classes of communications satellites and conclusions regarding dependence on system complexity are presented. Observations regarding inherent differences between commercially acquired systems and those procured by government organizations are also presented. A process is described where a new communications system in the formative stage may be compared against similarly "complex" missions of the recent past to balance risk within allotted time and funds. 1

Bearden, David A.

2002-01-01

264

Integrated Satellite Observations of the 2006 Eruption of Augustine Volcano  

USGS Publications Warehouse

Satellite observations played an important role in monitoring the 2006 eruption of Augustine Volcano. It represented the first opportunity for observers to use, in an operational setting, new Web-based tools and techniques developed by the Alaska Volcano Observatory remote sensing group. The 'Okmok Algorithm' was used to analyze thermal infrared satellite data and highlight changes in the style and phases of activity. Temperature measurements were used to estimate ash cloud heights, which compared favorably to radar and ground-based observations, although larger discrepancies were seen when compared to pilot reports. Brightness temperature difference techniques were used to locate and track the 14 ash clouds produced during the explosive phase of the eruption. Stacking of these analyses allowed the creation of composite maps showing the distribution of airborne ash. The data from these maps were further combined with information from local reports and samples of ashfall to create a prototype of a concentration map that could be used to assess the potential hazard an eruption represents to aircraft, infrastructure and human health.

Bailey, John E.; Dean, Kenneson G.; Dehn, Jonathan; Webley, Peter W.

2010-01-01

265

Satellite Observations of Desert Dust-induced Himalayan Snow Darkening  

NASA Technical Reports Server (NTRS)

The optically thick aerosol layer along the southern edge of the Himalaya has been subject of several recent investigations relating to its radiative impacts on the South Asian summer monsoon and regional climate forcing. Prior to the onset of summer monsoon, mineral dust from southwest Asian deserts is transported over the Himalayan foothills on an annual basis. Episodic dust plumes are also advected over the Himalaya, visible as dust-laden snow surface in satellite imagery, particularly in western Himalaya. We examined spectral surface reflectance retrieved from spaceborne MODIS observations that show characteristic reduction in the visible wavelengths (0.47 nm) over western Himalaya, associated with dust-induced solar absorption. Case studies as well as seasonal variations of reflectance indicate a significant gradient across the visible (0.47 nm) to near-infrared (0.86 nm) spectrum (VIS-NIR), during premonsoon period. Enhanced absorption at shorter visible wavelengths and the resulting VIS-NIR gradient is consistent with model calculations of snow reflectance with dust impurity. While the role of black carbon in snow cannot be ruled out, our satellite-based analysis suggests the observed spectral reflectance gradient dominated by dust-induced solar absorption during premonsoon season. From an observational viewpoint, this study underscores the importance of mineral dust deposition toward darkening of the western Himalayan snow cover, with potential implications to accelerated seasonal snowmelt and regional snow albedo feedbacks.

Gautam, Ritesh; Hsu, N. Christina; Lau, William K.-M.; Yasunari, Teppei J.

2013-01-01

266

Satellite observations of tropical cyclones during the 1990's  

NASA Technical Reports Server (NTRS)

Operational satellite advances expected in the area of tropical cyclone studies with the GOES I-M geosynchronous satellite and the polar orbiting NOAA K-M satellite are discussed. Major tropical cyclone quantities and processes and the required parameters are discussed, with emphasis on spatial and vertical resolution. The problem of insertions of satellite measurements into numerical models is addressed.

Shenk, William E.; Rodgers, Edward B.; Chang, Simon

1989-01-01

267

Antenna drive system for the Nimbus satellite  

NASA Technical Reports Server (NTRS)

A two-axis drive system is described for pointing a high gain antenna. Motion about each axis is provided by identical drive mechanisms. Only three gear passes are required to obtain the necessary 900:1 gear reduction. The drive system is a primary element of an experiment that will provide a real time data link between Nimbus and ground stations. Data are transmitted from Nimbus to the applications technology satellite, which relays the data to ground stations.

Wedlake, G. J.; Loudon, J. D.

1972-01-01

268

Observations of dust spikes on the Wind satellite  

NASA Astrophysics Data System (ADS)

Stimulated by the work on impulsive waveforms (spikes) on the STEREO satellites, we have investigated similar waveforms observed by the Wind/Waves Time Domain Sampler (TDS) on Wind. As Wind is spinning, and has antennas of different lengths with a significant separation, additional understanding of the impact and emission process can be expected. The surface, glass coated with Indium Tin Oxide, is different from that of the STEREOs, germanium coated mylar, which should also affect the processes. Only a small percentage of the spikes are due to interference of an expected kind. The rest are consistent with impacts of dust. Viewed in detail, the spikes attributed to dust impacts have a wide variety of waveforms, and a wide variety of parameters even for waveforms selected as similar. Observations and summaries will be presented. Progress toward a calibration of the observations, in terms of dust mass and energy, will be summarized.

Kellogg, Paul J.; Goetz, Keith; Monson, Steven

2013-04-01

269

Cooling systems for satellite remote sensing instrumentation  

NASA Technical Reports Server (NTRS)

The characteristics of a cryogenic cooling system for the Pollution Monitoring Satellite (PMS) are discussed. Studies were conducted to make the following determinations: (1) the characteristics and use of proven and state-of-the-art cryogenic cooling systems for six specified ranges of performance, (2) the system most applicable for each of the six cooling categories, and (3) conceptual designs for candidate system for each of the six representative cooling categories. The six cooling categories of electrical loads are defined. The desired mission life for the cooling system is two years with both continuous and intermittent operating conditions.

Copeland, R. J.; Oren, J. A.

1974-01-01

270

Role of light satellites in the high-resolution Earth observation domain  

NASA Astrophysics Data System (ADS)

Current 'classic' applications using and exploring space based earth imagery are exclusive, narrow niche tailored, expensive and hardly accessible. On the other side new, inexpensive and widely used 'consumable' applications will be only developed concurrently to the availability of appropriate imagery allowing that process. A part of these applications can be imagined today, like WWW based 'virtual tourism' or news media, but the history of technological, cultural and entertainment evolution teaches us that most of future applications are unpredictable -- they emerge together with the platforms enabling their appearance. The only thing, which can be ultimately stated, is that the definitive condition for such applications is the availability of the proper imagery platform providing low cost, high resolution, large area, quick response, simple accessibility and quick dissemination of the raw picture. This platform is a constellation of Earth Observation satellites. Up to 1995 the Space Based High Resolution Earth Observation Domain was dominated by heavy, super-expensive and very inflexible birds. The launch of Israeli OFEQ-3 Satellite by MBT Division of Israel Aircraft Industries (IAI) marked the entrance to new era of light, smart and cheap Low Earth Orbited Imaging satellites. The Earth Resource Observation System (EROS) initiated by West Indian Space, is based on OFEQ class Satellites design and it is capable to gather visual data of Earth Surface both at high resolution and large image capacity. The main attributes, derived from its compact design, low weight and sophisticated logic and which convert the EROS Satellite to valuable and productive system, are discussed. The major advantages of Light Satellites in High Resolution Earth Observation Domain are presented and WIS guidelines featuring the next generation of LEO Imaging Systems are included.

Fishman, Moshe

1999-12-01

271

Modeling Prairie Pothole Lakes: Linking Satellite Observation and Calibration (Invited)  

NASA Astrophysics Data System (ADS)

This paper examines the response of a complex lake wetland system to variations in climate. The focus is on the lakes and wetlands of the Missouri Coteau, which is part of the larger Prairie Pothole Region of the Central Plains of North America. Information on lake size was enumerated from satellite images, and yielded power law relationships for different hydrological conditions. More traditional lake-stage data were made available to us from the USGS Cottonwood Lake Study Site in North Dakota. A Probabilistic Hydrologic Model (PHM) was developed to simulate lake complexes comprised of tens-of-thousands or more individual closed-basin lakes and wetlands. What is new about this model is a calibration scheme that utilizes remotely-sensed data on lake area as well as stage data for individual lakes. Some ¼ million individual data points are used within a Genetic Algorithm to calibrate the model by comparing the simulated results with observed lake area-frequency power law relationships derived from Landsat images and water depths from seven individual lakes and wetlands. The simulated lake behaviors show good agreement with the observations under average, dry, and wet climatic conditions. The calibrated model is used to examine the impact of climate variability on a large lake complex in ND, in particular, the “Dust Bowl Drought” 1930s. This most famous drought of the 20th Century devastated the agricultural economy of the Great Plains with health and social impacts lingering for years afterwards. Interestingly, the drought of 1930s is unremarkable in relation to others of greater intensity and frequency before AD 1200 in the Great Plains. Major droughts and deluges have the ability to create marked variability of the power law function (e.g. up to one and a half orders of magnitude variability from the extreme Dust Bowl Drought to the extreme 1993-2001 deluge). This new probabilistic modeling approach provides a novel tool to examine the response of the behavior of a complex of closed lakes vary in scale from the footprint of a small house to that of a small city.

Schwartz, F. W.; Liu, G.; Zhang, B.; Yu, Z.

2009-12-01

272

Developing Observation Systems.  

ERIC Educational Resources Information Center

The first three chapters of this booklet describe the utilization of observation as a measurement technique, the types of observation systems available, and the necessary components of an observation system. The second part focuses on the following four commonly used observation systems: 1) primary reading checklist, 2) student affective behavior…

Roberson, E. Wayne

273

Distributed Satellite Communication System Design: First-Order Interactions between System and Network  

E-print Network

Distributed Satellite Communication System Design: First-Order Interactions between System to bankruptcy. The upfront capital required to implement a satellite communications system is staggering and performance of a system. Traditionally, the first step toward designing satellite communication systems

de Weck, Olivier L.

274

Observing the earth radiation budget from satellites - Past, present, and a look to the future  

NASA Technical Reports Server (NTRS)

Satellite measurements of the radiative exchange between the planet earth and space have been the objective of many experiments since the beginning of the space age in the late 1950's. The on-going mission of the Earth Radiation Budget (ERB) experiments has been and will be to consider flight hardware, data handling and scientific analysis methods in a single design strategy. Research and development on observational data has produced an analysis model of errors associated with ERB measurement systems on polar satellites. Results show that the variability of reflected solar radiation from changing meteorology dominates measurement uncertainties. As an application, model calculations demonstrate that measurement requirements for the verification of climate models may be satisfied with observations from one polar satellite, provided there is information on diurnal variations of the radiation budget from the ERBE mission.

House, F. B.

1985-01-01

275

Geodetic satellite observations in North American (solution NA-9)  

NASA Technical Reports Server (NTRS)

A new detailed geoidal map with claimed accuracies of plus or minus 2 meters (on land), based on gravimetric and satellite data, was presented. With the new geoid and the orthometric heights given, more reliable height constraints were calculated and applied. The basic purpose of this experiment was to compute the new solution NA9 by defining the origin of the system, from the point of view of error propagation, in the most favorable position applying inner constraints and imposing new weighted height constraints to all of the stations. The major differences with respect to formerly published adjustments are presented.

Mueller, I. I.; Reilly, J. P.; Soler, T.

1972-01-01

276

Satellite microwave observations of the Utah Great Salt Lake Desert  

NASA Technical Reports Server (NTRS)

Microwave data acquired over the Great Salt Lake Desert by sensors aboard Skylab and Nimbus 5 indicate that microwave emission and backscatter were strongly influenced by contributions from subsurface layers of sediment saturated with brine. This phenomenon was observed by Skylab's S-194 radiometer operating at 1.4 GHz, S-193 RADSCAT (Radiometer-Scatterometer) operating at 13.9 GHz and the Nimbus 5 ESMR (Electrically Scanning Microwave Radiometer) operating at 19.35 GHz. The availability of ESMR data over an 18 month period allowed an investigation of temporal variations. Aircraft 1.4 GHz radiometer data acquired two days after one of the Skylab passes confirm the satellites observations. Data from the ESMR revealed similar responses over the Bolivian deserts, which have geologic features similar to those of the Utah desert.

Ulaby, F. T.; Dellwig, L. F.; Schmugge, T. J.

1975-01-01

277

Solar power satellite system definition study, volume 7  

NASA Technical Reports Server (NTRS)

Guidelines and assumptions used in the design of a system of geosynchronous satellites for transmitting solar power to earth were discussed as well as the design evolutions of the principle types of solar power satellites and space support systems.

1977-01-01

278

Subtropical Gyre Variability Observed by Ocean Color Satellites  

NASA Technical Reports Server (NTRS)

The subtropical gyres of the world are extensive, coherent regions that occupy about 40% of the surface of the earth. Once thought to be homogeneous and static habitats, there is increasing evidence that mid-latitude gyres exhibit substantial physical and biological variability on a variety of time scales. While biological productivity within these oligotrophic regions may be relatively small, their immense size makes their total contribution significant. Global distributions of dynamic height derived from satellite altimeter data, and chlorophyll concentration derived from satellite ocean color data, show that the dynamic center of the gyres, the region of maximum dynamic height where the thermocline is deepest, does not coincide with the region of minimum chlorophyll concentration. The physical and biological processes by which this distribution of ocean properties is maintained, and the spatial and temporal scales of variability associated with these processes, are analyzed using global surface chlorophyll-a concentrations, sea surface height, sea surface temperature and surface winds from operational satellite and meteorological sources, and hydrographic data from climatologies and individual surveys. Seasonal and interannual variability in the areal extent of the subtropical gyres are examined using 8 months (November 1996 - June 1997) of OCTS and nearly 5 years (September 1997 - June 02) of SeaWiFS ocean color data and are interpreted in the context of climate variability and measured changes in other ocean properties (i.e., wind forcing, surface currents, Ekman pumping, and vertical mixing). The North Pacific and North Atlantic gyres are observed to be shrinking over this period, while the South Pacific, South Atlantic, and South Indian Ocean gyres appear to be expanding.

McClain, Charles R.; Signorini, Sergio R.; Christian, James R.

2002-01-01

279

The principle of the positioning system based on communication satellites  

Microsoft Academic Search

It is a long dream to realize the communication and navigation functionality in a satellite system in the world. This paper\\u000a introduces how to establish the system, a positioning system based on communication satellites called Chinese Area Positioning\\u000a System (CAPS). Instead of the typical navigation satellites, the communication satellites are configured firstly to transfer\\u000a navigation signals from ground stations, and

Guoxiang Ai; Huli Shi; Haitao Wu; Zhigang Li; Ji Guo

2009-01-01

280

Satellite Telemetry and Command using Big LEO Mobile Telecommunications Systems  

NASA Technical Reports Server (NTRS)

Various issues associated with satellite telemetry and command using Big LEO mobile telecommunications systems are presented in viewgraph form. Specific topics include: 1) Commercial Satellite system overviews: Globalstar, ICO, and Iridium; 2) System capabilities and cost reduction; 3) Satellite constellations and contact limitations; 4) Capabilities of Globalstar, ICO and Iridium with emphasis on Globalstar; and 5) Flight transceiver issues and security.

Huegel, Fred

1998-01-01

281

Indian Regional Navigation Satellites System (IRNSS) is the world's rst  

E-print Network

Indian Regional Navigation Satellites System (IRNSS) is the world's rst regional navigation system with its footprint primarily over the Indian subcontinent. The system is expected to have seven satellites in all, with three satellites in GEO stationary and four in GEO synchronous orbits (Kibe & Gowrishankar

Calgary, University of

282

Joint Polar Satellite System Science Seminar Annual Digest  

E-print Network

iii Joint Polar Satellite System Science Seminar Annual Digest 2013 #12;#12;Joint Polar Satellite System Science Seminar Annual Digest Page i From the Senior Program Scientist On behalf of the Joint Polar Satellite System (JPSS) Program Science, it is my pleasure to present this digest, which

283

Antartic sea ice, 1973 - 1976: Satellite passive-microwave observations  

NASA Technical Reports Server (NTRS)

Data from the Electrically Scanning Microwave Radiometer (ESMR) on the Nimbus 5 satellite are used to determine the extent and distribution of Antarctic sea ice. The characteristics of the southern ocean, the mathematical formulas used to obtain quantitative sea ice concentrations, the general characteristics of the seasonal sea ice growth/decay cycle and regional differences, and the observed seasonal growth/decay cycle for individual years and interannual variations of the ice cover are discussed. The sea ice data from the ESMR are presented in the form of color-coded maps of the Antarctic and the southern oceans. The maps show brightness temperatures and concentrations of pack ice averaged for each month, 4-year monthly averages, and month-to-month changes. Graphs summarizing the results, such as areas of sea ice as a function of time in the various sectors of the southern ocean are included. The images demonstrate that satellite microwave data provide unique information on large-scale sea ice conditions for determining climatic conditions in polar regions and possible global climatic changes.

Zwally, H. J.; Comiso, J. C.; Parkinson, C. L.; Campbell, W. J.; Carsey, F. D.; Gloersen, P.

1983-01-01

284

Arctic Sea ice studies with passive microwave satellite observations  

NASA Technical Reports Server (NTRS)

The objectives of this research are: (1) to improve sea ice concentration determinations from passive microwave space observations; (2) to study the role of Arctic polynyas in the production of sea ice and the associated salinization of Arctic shelf water; and (3) to study large scale sea ice variability in the polar oceans. The strategy is to analyze existing data sets and data acquired from both the DMSP SSM/I and recently completed aircraft underflights. Special attention will be given the high resolution 85.5 GHz SSM/I channels for application to thin ice algorithms and processes studies. Analysis of aircraft and satellite data sets is expected to provide a basis for determining the potential of the SSM/I high frequency channels for improving sea ice algorithms and for investigating oceanic processes. Improved sea ice algorithms will aid the study of Arctic coastal polynyas which in turn will provide a better understanding of the role of these polynyas in maintaining the Arctic watermass structure. Analysis of satellite and archived meteorological data sets will provide improved estimates of annual, seasonal and shorter-term sea ice variability.

Cavalieri, D. J.

1988-01-01

285

Observing tectonic plate motions and deformations from satellite laser ranging  

Microsoft Academic Search

The scope of geodesy has been greatly affected by the advent of artificial near-earth satellites. The present paper provides a description of the results obtained from the reduction of data collected with the aid of satellite laser ranging. It is pointed out that dynamic reduction of satellite laser ranging (SLR) data provides very precise positions in three dimensions for the

D. C. Christodoulidis; D. E. Smith; R. Kolenkiewicz; S. M. Klosko; M. H. Torrence

1985-01-01

286

Pico-satellite capabilities for telecommunication and Earth observation  

Microsoft Academic Search

Modern miniaturization technologies allow realization of satellites at very low masses. For the example of the pico-satellite UWE-1 (University Würzburg's Experimental satellite), design details for such spacecrafts with at a mass below 1 kg will be discussed. UWE-1 was launched in 2005 in order to optimize Internet Protocol parameters in adaptation to the measured space environment, specifically at significant delays

Marco Schmidt; Klaus Schilling

2008-01-01

287

A preliminary global oceanic cloud climatology from satellite albedo observations  

NASA Technical Reports Server (NTRS)

A predictive relationship is developed between over-ocean cloud system albedo and the cloud amount present, using as a data base ERB satellite microwave readings at 0.5-0.7 micron and the USAF three-dimensional nephanalysis archive. The ERB data provided global coverage at a resolution of 2.5 x 2.5 deg during the 1974-78 period. Regression analyses were performed on the amounts and albedos for several years of data for one month in order to detect seasonal variations. A logarithmic relationship was found between the cloud system albedo and cloud amount over the oceans, with negligible seasonal variance. The analysis is noted to apply only where low surface albedos are encountered, and further work to extend the study to continental vegetated areas is indicated.

Hughes, N. A.; Henderson-Sellers, A.

1983-01-01

288

The Global Ocean Observing System  

NASA Technical Reports Server (NTRS)

A Global Ocean Observing System (GOOS) should be established now with international coordination (1) to address issues of global change, (2) to implement operational ENSO forecasts, (3) to provide the data required to apply global ocean circulation models, and (4) to extract the greatest value from the one billion dollar investment over the next ten years in ocean remote sensing by the world's space agencies. The objectives of GOOS will focus on climatic and oceanic predictions, on assessing coastal pollution, and in determining the sustainability of living marine resources and ecosystems. GOOS will be a complete system including satellite observations, in situ observations, numerical modeling of ocean processes, and data exchange and management. A series of practical and economic benefits will be derived from the information generated by GOOS. In addition to the marine science community, these benefits will be realized by the energy industries of the world, and by the world's fisheries. The basic oceanic variables that are required to meet the oceanic and predictability objectives of GOOS include wind velocity over the ocean, sea surface temperature and salinity, oceanic profiles of temperature and salinity, surface current, sea level, the extent and thickness of sea ice, the partial pressure of CO2 in surface waters, and the chlorophyll concentration of surface waters. Ocean circulation models and coupled ocean-atmosphere models can be used to evaluate observing system design, to assimilate diverse data sets from in situ and remotely sensed observations, and ultimately to predict future states of the system. The volume of ocean data will increase enormously over the next decade as new satellite systems are launched and as complementary in situ measuring systems are deployed. These data must be transmitted, quality controlled, exchanged, analyzed, and archived with the best state-of-the-art computational methods.

Kester, Dana

1992-01-01

289

A Geostationary Satellite Constellation for Observing Global Air Quality: Status of the CEOS Activity  

NASA Astrophysics Data System (ADS)

Several countries and space agencies are currently planning to launch geostationary satellites in the 2017-2022 time frame to obtain atmospheric composition measurements for characterizing anthropogenic and natural distributions of tropospheric ozone, aerosols, and their precursors, which are important factors in understanding air quality and climate change. While a single geostationary satellite can view only a portion of the globe, it is possible for a minimum of three geostationary satellites, positioned to view Europe/Middle East/Africa, Asia/Australasia, and the Americas, to collectively provide near-global coverage. Harmonizing the planned geostationary missions to be contemporaneous and have common observing capabilities and data distribution protocols would synergistically enable critically needed understanding of the interactions between regional and global atmospheric composition and of the implications for air quality and climate. Such activities would directly address societal benefit areas of the Global Earth Observation System of Systems (GEOSS), including Health, Energy, Climate, Disasters, and Ecosystems, and are responsive to the requirements of each mission to provide advanced user services and societal benefits. Over the past 2 years, the Atmospheric Composition Constellation (ACC) of the Committee on Earth Observation Satellites (CEOS) has developed a white paper describing such collaboration and the benefits to be derived from it. The resulting ACC recommendations were endorsed by CEOS in May 2011. Here we will present an update on collaborative activities and next steps. This presentation is envisioned to serve as an introduction to the oral sessions associated with Session A.25.

Al-Saadi, J. A.; Zehner, C.

2011-12-01

290

Satellite Microwave Radar Observations of Antarctic Sea Ice. Chapter 8  

NASA Technical Reports Server (NTRS)

Historical data on Antarctic sea ice extent and concentration have traditionally been derived from visible and near-infrared images acquired by the polar-orbiting National Oceanic and Atmospheric Agency's (NOAA) meteorological satellites, using the Advanced Very High Resolution Radiometer (AVHRR), and more recently by the Defense Meteorological Satellite Program's Operational Linescan System (OLS). The limitation of these systems is that the majority of energy imparted to the Antarctic sea-ice system is transferred during b6y fast-moving low pressure systems. Since the Southern Ocean sea-ice cover is completely bounded at its lower latitude limit by open ocean, these "polar lows" transport large amounts of moisture (contained in warm air masses) over the outer ice cover. The result is that most, if not all, noteworthy periods of wind- and temperature-driven dynamic changes in the ice cover are accompanied by periods where the region is blanketed by cloud, and when the atmosphere is inherently more electromagnetically opaque. During storms, the probability with which the area is cloud covered is extremely high, thereby ruling out use of visible or near-infrared images as a practical method of monitoring the associated changes in ice conditions. Instead, Nimbus-7 Scanning Multichannel Microwave Radiometer (SMMR) and DMSP Special Sensor Microwave/imager (SSM/I) have been the primary workhorses to build up a microwave record of Antarctic sea-ice characteristics. Similar problems, however, occur in passive microwave retrievals of sea-ice concentration, and the algorithms are called into question during these periods of change. The influence of water vapor in the atmosphere alone can modify the ice concentration retrievals by fractions exceeding 105, and that retrievals of ice concentration must compensate for the atmospheric water vapor and liquid water contents.

Drinkwater, Mark R.

1998-01-01

291

Intelligent Satellite Data Information System (ISIS)  

NSDL National Science Digital Library

The Intelligent Satellite Data Information System is "the central user interface" to the data archived at the German Remote Sensing Data Center (DFD) and offers descriptions of (and facilitates access to) numerous online resources. For general information about remote sensing and the ISIS site, see the News section (including announcements of upcoming electronic resources), the Thesaurus (containing synonyms for about 7,000 important scientific terms), and the Infoboard section (including tutorials in English and German, a list of data products, and an array of links to related resources). The ISIS homepage also offers a new WWW-Gateway to the Data, in which users may search or browse Earth Science data "from various participating archive centers around the globe." For the latest satellite images, see the Special section, which features spectacular color images of The weather in Europe, Temperatures and vegetation, and Ozone-concentration, electron-density and chlorophyll-content.

292

The investigation of tethered satellite system dynamics  

NASA Technical Reports Server (NTRS)

A progress report is presented that deals with three major topics related to Tethered Satellite System Dynamics. The SAO rotational dynamics computer code was updated. The program is now suitable to deal with inclined orbits. The output has been also modified in order to show the satellite Euler angles referred to the rotating orbital frame. The three-dimensional high resolution computer program SLACK3 was developed. The code simulates the three-dimensional dynamics of a tether going slack taking into account the effect produced by boom rotations. Preliminary simulations on the three-dimensional dynamics of a recoiling slack tether are shown in this report. A program to evaluate the electric potential around a severed tether is immersed in a plasma. The potential is computed on a three-dimensional grid axially symmetric with respect to the tether longitudinal axis. The electric potential variations due to the plasma are presently under investigation.

Lorenzini, E.

1985-01-01

293

New options for satellite power systems /SPS/  

NASA Technical Reports Server (NTRS)

The operation of a satellite power system (SPS) involves the conversion of solar energy into electrical energy with the aid of facilities carried by a geosynchronous satellite, the transmission of the obtained energy to earth in the form of microwave radio frequency energy, and the conversion of the energy received on earth into dc current for distribution into the network. Attention is given to questions concerning suitable microwave radiation density, details of space transportation for the construction of the SPS, and suitable approaches for the transformation of the solar energy into electric energy. It appears that a Rankine cycle using cesium as the main working fluid and a steam bottoming cycle might have advantages over a Brayton cycle concept considered earlier. In the area of solar photovoltaic concepts GaAlAs cells have advantages over silicon cells related to lighter weight, efficiency, and resistance to space radiation. The required amount of gallium seems to become available.

Hanley, G. M.

1977-01-01

294

Astrometric observations of natural satellites and orbit update , Cheng X.1,2  

E-print Network

181 Astrometric observations of natural satellites and orbit update Xi X.J.1,2 , Cheng X.1 100039, China Abstract: This paper reports on our observing campaign of nature satellites and orbit research of photo plates. 1 Research History In 1985, we start our research on natural satellites

Paris-Sud XI, Université de

295

Satellite communications systems move into the twenty-first century  

Microsoft Academic Search

This paper discusses the evolution of communication satellite systems and communications satellite technology from the 1960's\\u000a to the 1990's. The paper identifies the key attributes of satellite communications that has driven this evolution and now\\u000a drives the future directions such systems will take. The paper then discusses the future direction of communication satellite\\u000a systems including DBS, MSS, FSS and hybrid

Leonard S. Golding

1998-01-01

296

Committee on Earth Observation Satellites (CEOS) Systems Engineering Office (SEO). Ocean Surface Topography (OST) Workshop, Ruedesheim an Rhein, Germany. [CEOS SEO Status Report  

NASA Technical Reports Server (NTRS)

The CEOS Systems Engineering Office will present a 2007 status report of the CEOS constellation process, present a new systems engineering framework, and analysis results from the GEO Societal Benefit Area (SBA) assessment and the OST constellation requirements assessment.

Killough, Brian D., Jr.

2008-01-01

297

Internal solitary wave propagation observed by tandem satellites  

NASA Astrophysics Data System (ADS)

solitary waves (ISWs) are observed 2 times within 30 min in synthetic aperture radar (SAR) image pairs from the Envisat and ERS-2 tandem satellites. Three pairs of SAR images were acquired in the South China Sea (SCS) in April 2007, August 2008, and March 2009, and 13 ISWs were tracked between the image pair in an ArcGIS environment. The phase speeds of these ISWs are calculated from their spatial displacement and time interval. The resultant ISW speeds agree well with the theoretical values estimated from the Sturm-Louisville equation using local bathymetric and monthly climatology ocean stratification data. This technique reveals the spatial variation in the ISWs speed in the water depth between 100 and 4000 m in the SCS. The study shows that ISWs speed is mainly affected by bottom topography and generally decreases from deep to shallow water from east to west and from south to north.

Liu, Bingqing; Yang, Hong; Zhao, Zhongxiang; Li, Xiaofeng

2014-03-01

298

Earth observations satellite data policy: Process and outcome  

SciTech Connect

The National Aeronautics and Space Administration (NASA) develops, launches, and operates satellites to observe and monitor the Earth and its environment. This study categorizes each program based on the relationship between NASA and external organizations. A program can be an autonomous mission undertaken for NASA`s own constituency, or it can involve a client agency or a partner. These relationships affect how data policy decisions are made and implemented, and how the valuable output of NASA`s Earth observations satellites is managed. The process in NASA for determining which programs will be approved is very informal. Ideas and concepts surface and reach the consciousness of NASA management; if sufficient support is achieved, a proposal can move to the feasibility study phase and from there become an approved and funded mission. The handling of data can be an important consideration in generating political support for program approval. Autonomous programs tend to have decisions made at lower levels and documented informally or not at all. Data policy is part of routine implementation of programs and does not generally rise to the visibility of the agency head or congressional staff or the Executive Office of the President. Responsibility for data management for autonomous missions is retained at NASA centers. Client programs involve higher level decision makers, and are the subject of political interest because they cross agency boundaries. The data policy process includes presidential statements on data access. As part of the client relationship, NASA often provides resources to the client for data handling and analysis, and shares these responsibilities. Data policy for partner programs is the result of bargaining between the partners, either foreign government agencies or private companies.

Shaffer, L.R.

1994-12-31

299

FIDEX: An expert system for satellite diagnostics  

NASA Technical Reports Server (NTRS)

A Fault Isolation and Diagnostic Expert system (FIDEX) was developed for communication satellite diagnostics. It was designed specifically for the 30/20 GHz satellite transponder. The expert system was designed with a generic structure and features that make it applicable to other types of space systems. FIDEX is a frame based system that enjoys many of the inherent frame base features, such as hierarchy that describes the transponder's components, with other hierarchies that provide structural and fault information about the transponder. This architecture provides a flexible diagnostic structure and enhances maintenance of the system. FIDEX also includes an inexact reasoning technique and a primitive learning ability. Inexact reasoning was an important feature for this system due to the sparse number of sensors available to provide information on the transponder's performance. FIDEX can determine the most likely faulted component under the constraint of limited information. FIDEX learns about the most likely faults in the transponder by keeping a record of past established faults. FIDEX also has the ability to detect anomalies in the sensors that provide information on the transponders performance.

Durkin, John; Tallo, Donald; Petrik, Edward J.

1991-01-01

300

Satellite communications systems and technology. Executive Summary  

NASA Technical Reports Server (NTRS)

NASA and the National Science Foundation (NSF) commissioned a panel of US experts to study the international status of satellite communications systems and technology. The study covers emerging systems concepts, applications, services, and the attendant technologies. The panel members travelled to Europe, Japan, and Russia to gather information first-hand. They visited 17 sites in Europe, 20 sites in Japan, and four in Russia. These included major manufacturers, government organizations, service providers, and associated R&D facilities. The panel's report was reviewed by the sites visited, by the panel, and by representatives of US industry. The report details the information collected and compares it to US activities.

Edelson, Burton I.; Pelton, Joseph N.; Bostian, Charles W.; Brandon, William T.; Chan, Vincent W. S.; Hager, E. Paul; Helm, Neil R.; Jennings, Raymond D.; Kwan, Robert; Mahle, Christoph E.

1993-01-01

301

Engineering calculations for communications satellite systems planning  

NASA Technical Reports Server (NTRS)

Observed solution times were analyzed for the extended gradient and cyclic coordinate search procedures. The times used in the analysis come from computer runs made during a previously-reported experiment conducted to assess the quality of the solutions to a BSS synthesis problem found by the two search methods. The results of a second experiment with a Fixed Satellite Service (FSS) test problem are also presented. Computational results are summarized for mixed integer programming approaches for solving FSS synthesis problems. A promising heuristic algorithm is described. A synthesis model is discussed for orbital arc allotment optimization. Research plans for the near future are also presented.

Reilly, C. H.; Levis, C. A.; Buyukdura, O. M.; Mount-Campbell, C. A.

1986-01-01

302

Pseudo-coherent demodulation for mobile satellite systems  

NASA Technical Reports Server (NTRS)

This paper proposes three so-called pseudo-coherent demodulation schemes for use in land mobile satellite channels. The schemes are derived based on maximum likelihood (ML) estimation and detection of an N-symbol observation of the received signal. Simulation results for all three demodulators are presented to allow comparison with the performance of differential PSK (DPSK) and ideal coherent demodulation for various system parameter sets of practical interest.

Divsalar, Dariush; Simon, Marvin K.

1993-01-01

303

EUV observation from the Earth-orbiting satellite, EXCEED  

NASA Astrophysics Data System (ADS)

An Earth-orbiting small satellite “EXtreme ultraviolet spectrosCope for ExosphEric Dynamics” (EXCEED) which will be launched in 2012 is under development. The mission will carry out spectroscopic and imaging observation of EUV (Extreme Ultraviolet: 60-145 nm) emissions from tenuous plasmas around the planets (Venus, Mars, Mercury, and Jupiter). It is essential for EUV observation to put on an observing site outside the Earth’s atmosphere to avoid the absorption. It is also essential that the detection efficiency must be very high in order to catch the faint signals from those targets. In this mission, we employ cesium iodide coated microchannel plate as a 2 dimensional photon counting devise which shows 1.5-50 times higher quantum detection efficiency comparing with the bared one. We coat the surface of the grating and entrance mirror with silicon carbides by the chemical vapor deposition method in order to archive the high diffraction efficiency and reflectivity. The whole spectrometer is shielded by the 2 mm thick stainless steel to prevent the contamination caused by the high energy electrons from the inner radiation belt. In this paper, we will introduce the mission overview, its instrument, and their performance.

Yoshioka, K.; Murakami, G.; Yoshikawa, I.; Ueno, M.; Uemizu, K.; Yamazaki, A.

2010-01-01

304

The third-generation satellite laser ranging system at Shanghai Observatory.  

NASA Astrophysics Data System (ADS)

The paper describes the performance of the third-generation satellite laser ranging system at the Shanghai Observatory, Academia Sinica, and the observation summary of Lageos, Ajisai and Starlette satellites in recent two years. It has been shown that the ranging accuracy of this laser ranging system is about 5 cm (r.m.s.), by means of satellite orbital fitting and the ground target ranging experiments.

Yang, Fu-Min; Tan, De-Tong; Xiao, Chi-Kun; Zhu, You-Ming; Shi, Xiao-Liang; Chen, Zhong-De; Chen, Wan-Zhen; He, Hui-Jian; Li, Yong-Chun; Wang, Yu-Chen; Yan, Jun-Min; Han, Yan-Peng; Yu, Hai-Chuan

1990-07-01

305

Combining numerical ocean circulation models with satellite observations in a trajectory forecast system: a rapid response to the Deepwater Horizon oil spill  

Microsoft Academic Search

The Deepwater Horizon oil spill presented an unprecedented threat to the Gulf of Mexico coastline and living marine resources, and possibly to that of the southeastern USA. Needed for mitigation efforts and to guide scientific investigations was a system for tracking the oil, both at the surface and at depth. We report on such system, implemented immediately upon spill onset,

Yonggang Liu; Robert H. Weisberg; Chuanmin Hu; Lianyuan Zheng

2011-01-01

306

On the frame tie between VLBI and GNSS established by VLBI observations to satellites  

NASA Astrophysics Data System (ADS)

Very Long Baseline Interferometry (VLBI) and Global Navigation Satellite Systems (GNSS) are two of four space geodetic techniques contributing to the International Terrestrial Reference Frame (ITRF). For observing natural radiation of extragalactic radio sources with large radio telescopes on the one hand, and receiving artificial radio signals emitted by satellites with compact GNSS antennas on the other hand, both systems use different hardware. If we want to generate combined products in terms of station coordinates or Earth Orientation Parameters, the systems have to be referenced to each other carefully. Today, the determination of this so-called frame tie is the limiting factor for the establishment of precise reference frames. Plus, for a consistent multi-technique combination in the sense of GGOS, new strategies and ways of observation need to be identified. In this presentation, we discuss the derivation of the frame tie between VLBI and GNSS by using VLBI observations to satellites of the GNSS. Therefore, such observations are simulated and analysed in the standard VLBI method, solving for station coordinates. In the analysis, common troposphere delays and common clocks are determined at the stations. The accuracy of the frame tie is finally assessed by comparison of station coordinates of the observing sites in the quasar and the satellite frame. Monte Carlo simulations allow us to give estimates of the expected accuracies of the products, namely the station coordinates and the frame ties in terms of Helmert parameters. Our results are generated using different ways of including VLBI-GNSS observations in routine 24h VLBI experiments as well as changing analysis strategies.

Plank, Lucia; Boehm, Johannes; Schuh, Harald

2014-05-01

307

Mutual Events of the Uranian Satellites Observed with the Faulkes Telescopes  

NASA Astrophysics Data System (ADS)

The 2007 Uranian Equinox allowed unique observations of the planet, its rings and satellites, possible only twice during the planet's 84 year orbit. Among these were mutual eclipses and occultations between the 5 classical satellites Ariel, Umbriel, Titania, Oberon and Miranda. These ``mutual'' events are extremely useful as reality checks of satellite ephemerides. In addition, they provide an opportunity to improve our knowledge of the satellite orbits and the system constants. We observed several mutual events in 2007 using the 2m Faulkes Telescopes North (FTN) and South (FTS) located in Haleakala, Maui and Siding Spring, Australia respectively, operated by the Las Cumbres Observatory Global Telescope (LCOGT) network. To mitigate against Uranus' glare, we utilized wide-band imaging in the near-IR, a small image scale and a posteriori subtraction of the planet's PSF. We obtained positive detections of six mutual events, three occultations and three eclipses, among these satellites. Three of these events involved Miranda, a difficult target due to its proximity to Uranus. Furthermore, we recorded at least two events that were predicted to occur with high confidence but did not, in fact, occur. During this presentation we will describe our observing strategy, operational setup and data reduction techniques and present examples of obtained lightcurves. Our observational results have been compared with predictions based on ephemerides by Laskar and Jacobson (1987; GUST86), by Lainey and Arlot (2006; LA06) and by Rush and Jacobson (2007; RJ07). Offsets with respect to the Voyager-era GUST86 are quite significant, of the order of minutes in the event midtimes. Smaller, yet significant trends in the data also appear with respect to LA06 and RJ07. We will discuss the nature of these trends and how they can be interpreted in terms of potential improvements in our knowledge of the Uranian system.

Christou, Apostolos; Lewis, F.; Hidas, M. G.; Brown, T. M.; Roche, P.

2008-09-01

308

Monitoring tropical cyclone evolution with NOAA satellite microwave observations  

NASA Technical Reports Server (NTRS)

NOAA satellite microwave soundings, which penetrate high clouds, delineate the development and dissipation of the upper tropospheric warm core associated with a tropical cyclone. The storm's 'core" may be detected from microwave imagery. Vertical cross sections reveal the intensification of the upper tropospheric warm core as the storm develops, and the downward propagation of the warm core as the storm dissipates. Excellent correlation is found between the horizontal Laplacian of an upper tropospheric temperature field and the intensity of the storm, as categorized by its surface central pressure and maximum sustained wind speed at the eye wall. The microwave monitoring of tropical cyclones is achieved in real time at the University of Wisconsin's Space Science and Engineering Center through high-speed teleconnections to direct readout receiving systems at Wallops Island, Virginia and Redwood City, California.

Velden, C.; Smith, W. L.

1983-01-01

309

47 CFR 5.64 - Special provisions for satellite systems.  

Code of Federal Regulations, 2013 CFR

...disclosing that fact shall be included in the debris mitigation disclosure. Such systems shall also indicate the anticipated evolution over time of the orbit of the proposed satellite or satellites. Where a space station operator requests the...

2013-10-01

310

47 CFR 5.64 - Special provisions for satellite systems.  

...disclosing that fact shall be included in the debris mitigation disclosure. Such systems shall also indicate the anticipated evolution over time of the orbit of the proposed satellite or satellites. Where a space station operator requests the...

2014-10-01

311

Communications satellite systems operations with the space station, volume 2  

NASA Technical Reports Server (NTRS)

A financial model was developed which described quantitatively the economics of the space segment of communication satellite systems. The model describes the economics of the space system throughout the lifetime of the satellite. The expected state-of-the-art status of communications satellite systems and operations beginning service in 1995 were assessed and described. New or enhanced space-based activities and associated satellite system designs that have the potential to achieve future communications satellite operations in geostationary orbit with improved economic performance were postulated and defined. Three scenarios using combinations of space-based activities were analyzed: a spin stabilized satellite, a three axis satellite, and assembly at the Space Station and GEO servicing. Functional and technical requirements placed on the Space Station by the scenarios were detailed. Requirements on the satellite were also listed.

Price, K.; Dixon, J.; Weyandt, C.

1987-01-01

312

Photoelectron flux variations observed from the FAST satellite  

NASA Astrophysics Data System (ADS)

This paper examines high resolution (?E/E = 0.15) photoelectron energy spectra from 10 eV to 1 keV, created by solar irradiances between 1.2 and 120 nm. The observations were made from the FAST satellite at ˜3000 km, equatorward of the auroral oval for the July August, 2002 solar rotation. These data are compared with the solar irradiance observed by the Solar EUV Experiment (SEE) on the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite and fluxes calculated using the Field Line Interhemispheric Plasma (FLIP) code. The 41 eV photoelectron flux, which corresponds to solar EUV fluxes near 20 nm, shows a clear solar rotation variation in very good agreement with the EUV flux measurements. This offers the possibility that the 41 eV photoelectron flux could be used as a check on measured solar EUV fluxes near 20 nm. Because of unexpected noise, the solar rotation signal is not evident in the integral photoelectron flux between 156 and 1000 eV corresponding to EUV wavelengths between 0.1 and 7 nm measured by the SEE instrument. Examination of daily averaged photoelectron fluxes at energies between 25 and 500 eV show significant changes in the photoelectron spectra in response X and M class flares. The intensity of photoelectrons produced in this energy region is primarily due to two very narrow EUV wavelength regions at 2.3 and 3 nm driving Auger photoionization in O at 500 eV and N2 at ˜360 eV. Comparison of calculated and daily averaged electron fluxes shows that the HEUVAC model solar spectrum used in the FLIP code does not reproduce the observed variations in photoelectron intensity. In principle, the 21 discrete photoelectron energy channels could be used to improve the reliability of the solar EUV fluxes at 2.3 and 3 nm inferred from broad band observations. In practice, orbital biases in the way the data were accumulated and/or noise signals arising from natural and anthropogenic longitudinally restricted sources of ionization complicate the application of this technique.

Peterson, W. K.; Woods, T. N.; Chamberlin, P. C.; Richards, P. G.

2008-09-01

313

Satellite microwave observations of soil moisture variations. [by the microwave radiometer on the Nimbus 5 satellite  

NASA Technical Reports Server (NTRS)

The electrically scanning microwave radiometer (ESMR) on the Nimbus 5 satellite was used to observe microwave emissions from vegetated and soil surfaces over an Illinois-Indiana study area, the Mississippi Valley, and the Great Salt Lake Desert in Utah. Analysis of microwave brightness temperatures (T sub B) and antecedent rainfall over these areas provided a way to monitor variations of near-surface soil moisture. Because vegetation absorbs microwave emission from the soil at the 1.55 cm wavelength of ESMR, relative soil moisture measurements can only be obtained over bare or sparsely vegetated soil. In general T sub B increased during rainfree periods as evaporation of water and drying of the surface soil occurs, and drops in T sub B are experienced after significant rainfall events wet the soil. Microwave observations from space are limited to coarse resolutions (10-25 km), but it may be possible in regions with sparse vegetation cover to estimate soil moisture conditions on a watershed or agricultural district basis, particularly since daily observations can be obtained.

Schmugge, T. J.; Rango, A.; Neff, R.

1975-01-01

314

The Role of Satellite Earth Observation Data in Monitoring and Verifying International Environmental Treaties  

NASA Technical Reports Server (NTRS)

The term verification implies compliance verification in the language of treaty negotiation and implementation, particularly in the fields of disarmament and arms control. The term monitoring on the other hand, in both environmental and arms control treaties, has a much broader interpretation which allows for use of supporting data sources that are not necessarily acceptable or adequate for direct verification. There are many ways that satellite Earth observation (EO) data can support international environmental agreements, from national forest inventories to use in geographic information system (GIs) tools. Though only a few references to satellite EO data and their use exist in the treaties themselves, an expanding list of applications can be considered in support of multilateral environmental agreements (MEAs). This paper explores the current uses of satellite Earth observation data which support monitoring activities of major environmental treaties and draws conclusions about future missions and their data use. The scope of the study includes all phases of environmental treaty fulfillment - development, monitoring, and enforcement - and includes a multinational perspective on the use of satellite Earth observation data for treaty support.

Johnston, Shaida

2004-01-01

315

Domestic satellite communication system to be established in China  

NASA Astrophysics Data System (ADS)

The establishment of a domestic satellite communication system for China is discussed. To experiment, China built miniaturized ground stations and used the idle transponders of two INTELSAT satellites. The experiment was divided into three phases: verification and test of ground facilities; test of channel operations; and functional test of the Chinese built ground facilities. From a technical and economic point of view, developing China's domestic satellite communication system by leasing foreign satellites and building China's own ground stations is both efficient and effective.

Ruhou, Z.; Yucheng, B.

1984-01-01

316

Advanced Microelectronics Technologies for Future Small Satellite Systems  

NASA Technical Reports Server (NTRS)

Future small satellite systems for both Earth observation as well as deep-space exploration are greatly enabled by the technological advances in deep sub-micron microelectronics technologies. Whereas these technological advances are being fueled by the commercial (non-space) industries, more recently there has been an exciting new synergism evolving between the two otherwise disjointed markets. In other words, both the commercial and space industries are enabled by advances in low-power, highly integrated, miniaturized (low-volume), lightweight, and reliable real-time embedded systems. Recent announcements by commercial semiconductor manufacturers to introduce Silicon On Insulator (SOI) technology into their commercial product lines is driven by the need for high-performance low-power integrated devices. Moreover, SOI has been the technology of choice for many space semiconductor manufacturers where radiation requirements are critical. This technology has inherent radiation latch-up immunity built into the process, which makes it very attractive to space applications. In this paper, we describe the advanced microelectronics and avionics technologies under development by NASA's Deep Space Systems Technology Program (also known as X2000). These technologies are of significant benefit to both the commercial satellite as well as the deep-space and Earth orbiting science missions. Such a synergistic technology roadmap may truly enable quick turn-around, low-cost, and highly capable small satellite systems for both Earth observation as well as deep-space missions.

Alkalai, Leon

1999-01-01

317

Satellite Power System (SPS) student participation  

NASA Technical Reports Server (NTRS)

A assessment of methods which are appropriate to initiate student participation in the discussion of a satellite power system (SPS) is presented. Methods which are incorporated into the campus environment and the on-going learning experience are reported. The discussion of individual methods for student participation includes a description of the technique, followed by comments on its enhancing and limiting factors, references to situations where the method has been demonstrated, and a brief consideration of cost factors. The two categories of recommendations presented are: an outline of fourteen recommendations addressing specific activities related to student participation in the discussion of SPS, and three recommendations pertaining to student participation activities in general.

Ladwig, A.; David, L.

1978-01-01

318

DCS/FTS Commercial Satellite Communications System  

NASA Astrophysics Data System (ADS)

In order to control the rising costs of telephonic services and meeting the increasing demand for wideband video and data services within U.S. Federal Government agencies, the Defense Communications Agency and the General Services Administration have begun the implementation of a leased Commercial Satellite Communications System. Service volume demand, commonality of service requirements, and common geographic communities of interest facilitate economies of scale in the course of meeting DOD and other Federal agencies' objectives. The service, which incorporates the Federal Telecommunications Service and is therefore designated DCS/FTS, is presently studied with respect to military and national objectives.

Shimabukuro, T.; Rosner, R.; Pearsall, C.

319

Vertical Component of Satellite Navigation Systems  

NASA Astrophysics Data System (ADS)

The altitude is one of four coordinates of the user's position obtained from Satellite Navigation System (SNS) measurements. The distributions (in per cent) of VDOP coefficient value for different constellations of three SNS - GPS, GLONASS and Galileo - for different masking elevation angles for different user's latitudes are presented in the paper. The results of the measurements of GPS position and vertical accuracy in mode "3D" and position accuracy in mode "2D" for different GPS receivers and different receiver's antenna heights are demonstrated also. Additionally the use of vertical component of SNS in maritime navigation like the determination highly accurate sea-floor depths is presented.

Januszewski, Jacek

2010-01-01

320

Satellite Observations of Antarctic Sea Ice Thickness and Volume  

NASA Technical Reports Server (NTRS)

We utilize satellite laser altimetry data from ICESat combined with passive microwave measurements to analyze basin-wide changes in Antarctic sea ice thickness and volume over a 5 year period from 2003-2008. Sea ice thickness exhibits a small negative trend while area increases in the summer and fall balanced losses in thickness leading to small overall volume changes. Using a five year time-series, we show that only small ice thickness changes of less than -0.03 m/yr and volume changes of -266 cu km/yr and 160 cu km/yr occurred for the spring and summer periods, respectively. The calculated thickness and volume trends are small compared to the observational time period and interannual variability which masks the determination of long-term trend or cyclical variability in the sea ice cover. These results are in stark contrast to the much greater observed losses in Arctic sea ice volume and illustrate the different hemispheric changes of the polar sea ice covers in recent years.

Kurtz, Nathan; Markus, Thorsten

2012-01-01

321

Lunar Crustal Modeling of Mare Orientale from Clementine Satellite Observations  

NASA Astrophysics Data System (ADS)

Clementine satellite gravity and altimetry observations were analyzed in lunar spherical coordinates for density variations that may be related to the crustal features and evolution of Mare Orientale. The analysis considered 2-degree gridded free-air gravity anomaly and LIDAR topographic estimates for a 68-degree by 68-degree region of the moon centered roughly on Mare Orientale. At this scale of coverage, the gravity anomalies appear to be dominated almost completely by crustal density variations related to surface topography, crustal isostasy, mantle topography, and meteorite impact. The topography of the study region includes over 11 km of relief, the gravity effect of which we modeled in lunar spherical coordinates by Gauss-Legendre quadrature integration assuming a topographic density of 2.8 g/cc. We observed substantial positive and negative correlations between the free-air and topographic gravity anomalies that seriously limit the utility of simple Bouguer gravity anomalies for lunar subsurface studies. Using the wavenumber correlation spectrum between the free-air and topographic gravity anomalies, we designed correlation filters to extract the the correlative anomalies in the two data sets.

von Frese, R. R. B.; Tan, L.; Potts, L. V.; Merry, C. J.; Bossler, J. D.

1996-03-01

322

SEU induced errors observed in microprocessor systems  

SciTech Connect

In this paper, the authors present software tools for predicting the rate and nature of observable SEU induced errors in microprocessor systems. These tools are built around a commercial microprocessor simulator and are used to analyze real satellite application systems. Results obtained from simulating the nature of SEU induced errors are shown to correlate with ground-based radiation test data.

Asenek, V.; Underwood, C.; Oldfield, M. [Univ. of Surrey, Guildford (United Kingdom). Surrey Space Centre] [Univ. of Surrey, Guildford (United Kingdom). Surrey Space Centre; Velazco, R.; Rezgui, S.; Cheynet, P. [TIMA Lab., Grenoble (France)] [TIMA Lab., Grenoble (France); Ecoffet, R. [Centre National d`Etudes Spatiales, Toulouse (France)] [Centre National d`Etudes Spatiales, Toulouse (France)

1998-12-01

323

The Satellite System for the VSOP-2 mission  

NASA Astrophysics Data System (ADS)

VSOP-2 is a next generation space VLBI project following the VSOP project Over all mission view of the mission is presented by Hirabayashi 2006 in this meeting We present the design of the satellite system for the VSOP-2 mission New functions of the satellite relative to the VSOP-2 mission is as follows 1 Observing frequency till 43 GHz 2 Dual polarization cooled receivers for 22 and 43 GHz for getting higher sensitivity and the polarization observation 3 High data rate sampling and data transfer 1 Gbps for the sensitivity of the continuum sources 4 High speed maneuver and high accuracy navigation system for the phase-referencing observation The satellite is designed to be launched M-V rocket in JAXA Its mass and total power are estimated to be 910 kg and 1 8 kW respectively Nominal orbit is elliptical with 25 000 apogee height and 1 000 km perigee height with 7 5 hour period We use the deployable modular type antenna for the 9-m main dish of the VSOP-2 satellite The deployment mechanism is same as that of the ETS-VIII mission in JAXA The main dish is consist of 7 modules and each module is newly developed to get higher surface accuracy than that of ETS-VIII and tested The cooled HEMT receiver is designed with using the on-board starling cycle cooler which have already developed for Suzaku X-ray astronomy mission and Akari Astro-F Infrared astronomy mission We finished the concept design of the receivers High date rate processing and data transfer system is also another challenge of the system We plan to use 37-38 GHz for

Murata, Y.; Hirabayashi, H.; Natori, M. C.; Edwards, P. G.; Asaki, Y.; Mochizuki, N.; Inoue, M.; Kameno, S.; Kono, Y.; Kasuga, T.; VSOP-2 Team

324

Monitoring of global geodynamic processes using satellite observations  

NASA Astrophysics Data System (ADS)

To study mechanisms of destructive geodynamic phenomena including determination of places of possible severe earthquakes, volcano eruptions and some other natural hazards, it is important to have means to evolve areas where maximum changes of the displacement velocities and the terrestrial crust vertical movements are possible. The previous experience has shown that the satellite geodesy techniques including global navigation systems and satellite laser ranging are the most effective for research activities in this field. Permanent control of secular movement of GPS-stations of the international geodynamic network, located in Russia, has allowed improving the reference coordinate frame for North Eurasia since Russian network stations provide representative covering of the largest stable areas (the Siberian and the East European) of the Eurasian plate. Along its southern border, there is a zone consisting of a great number of microplates surrounding the South-Eurasian stable plate. Interaction of these small plates and blocks influences distribution of seismic stresses in internal parts of the continent that is confirmed by the highest seismic activity of the triangle bordered by thrusts of the Himalayas and faults of the Pamirs, the Tien-Shan, the Baikal and the North-Eastern China. One of the active tectonic zones of Egypt located in Aswan, is characterized by regional basement rock uplift and regional faulting. In 1997, the African Regional Geodynamic Network was developed around the northern part of Lake Nasser, consists of 11 points, on both sides of the Lake. Its main goal is to study the geodynamical behavior around the northern part of the lake. The collected data were processed using the Bernese software version 5.0. From the velocity results, including also the African plate motion, it can be noticed that all stations of this network are moved to the northeast direction and it is typically the direction of the African plate motion.

Tatevian, S. K.; Attia, G. F.; Abou-Aly, N.; Ghoneim, R.; Hegazy, M.

2014-06-01

325

Advanced Satellite Sounding: The Benefits of Hyperspectral Observation - 2nd Edition  

NSDL National Science Digital Library

This lesson is an update to the 2008 expert lecture on hyperspectral observations presented by Dr. Mitch Goldberg, Program Scientist for NOAA's Joint Polar Satellite System (JPSS) Program. The lesson discusses what hyperspectral observations are, how they are made, some current products, their contributions to improved monitoring of the atmosphere, oceans, and land surfaces, as well as their impact on numerical weather prediction. The lesson begins by discussing the importance of satellite observing systems. From there, it reviews the principles of remote sensing that are needed for deriving products from hyperspectral infrared observations. The third and largest section of the lesson examines results from and operational applications of the AIRS, IASI, and CrIS hyperspectral sounders. The final section discusses the importance of hyperspectral soundings from geostationary satellites. The lesson has been updated from the original presentation to include information about NASA and NOAA's new polar orbiting programs and CrIS, the Cross-track Infrared Sounder on the Suomi NPP polar orbiter.

Comet

2013-07-09

326

Arctic Sea Ice Thickness from Satellite Observations, Aircraft Field Campaign Measurements, and Numerical Model Simulations  

NASA Astrophysics Data System (ADS)

Sea ice is an important indicator and effective modulator of regional and global climate change because it significantly affects the complex exchanges of momentum, heat, and mass between the sea and atmosphere. At present, there are datasets for Arctic sea ice thickness from satellite observations, aircraft field campaign measurements, numerical model simulations, and some in-situ measurements. Among satellite derived data sets, one satellite ice thickness product has been generated using NASA's Ice, Cloud and Land Elevation Satellite (ICESat) Geoscience Laser Altimeter System (GLAS) observations (Kwok et al., 2009), another has been produced from long-term optical (visible, near-IR, and thermal IR) imager data from NOAA Polar Orbiting Satellites (Wang et al., 2010). The approaches are completely different: the ICESat product estimates ice thickness from surface elevation; the optical imager approach estimates ice thickness by solving the surface energy budget equation. NASA's IceBridge program fills the gap between the loss of ICESat in 2010 and the launch of ICESat-2 in 2016. IceBridge employs an aircraft for altimeter and other measurements of the ice sheets and sea ice. The IceBridge Snow Radar, Digital Mapping System (DMS), Continuous Airborne Mapping By Optical Translator (CAMBOT), and Airborne Topographic Mapper (ATM) instruments can be used to estimate ice thickness with a methodology similar to that used for ICESat. Ice thickness has also been modeled with the numerical model called Pan-Arctic Ice Ocean Modeling and Assimilation System (PIOMAS) (Zhang and Rothrock, 2003). Arctic sea ice thickness estimates from these different data sources will be examined and inter-compared to evaluate their consistency and validity with in-situ measurements. Arctic sea ice thickness variations over time and space will be also investigated.

Wang, X.; Kwok, R.; Zhang, J.; Liu, Y.; Key, J.

2013-12-01

327

National Satellite Forest Monitoring systems for REDD+  

NASA Astrophysics Data System (ADS)

Reducing Emissions from Deforestation and Forest Degradation (REDD) is an effort to create a financial value for the carbon stored in forests, offering incentives for developing countries to reduce emissions from forested lands and invest in low-carbon paths to sustainable development. "REDD+" goes beyond deforestation and forest degradation, and includes the role of conservation, sustainable management of forests and enhancement of forest carbon stocks. In the framework of getting countries ready for REDD+, the UN-REDD Programme assists developing countries to prepare and implement national REDD+ strategies. For the monitoring, reporting and verification, FAO supports the countries to develop national satellite forest monitoring systems that allow for credible measurement, reporting and verification (MRV) of REDD+ activities. These are among the most critical elements for the successful implementation of any REDD+ mechanism. The UN-REDD Programme through a joint effort of FAO and Brazil's National Space Agency, INPE, is supporting countries to develop cost- effective, robust and compatible national monitoring and MRV systems, providing tools, methodologies, training and knowledge sharing that help countries to strengthen their technical and institutional capacity for effective MRV systems. To develop strong nationally-owned forest monitoring systems, technical and institutional capacity building is key. The UN-REDD Programme, through FAO, has taken on intensive training together with INPE, and has provided technical help and assistance for in-country training and implementation for national satellite forest monitoring. The goal of the support to UN-REDD pilot countries in this capacity building effort is the training of technical forest people and IT persons from interested REDD+ countries, and to set- up the national satellite forest monitoring systems. The Brazilian forest monitoring system, TerraAmazon, which is used as a basis for this initiative, allows countries to adapt it to country needs and the training on the TerraAmazon system is a tool to enhance existing capacity on carbon monitoring systems. The support with the National Forest Monitoring System will allow these countries to follow all actions related to the implementation of its national REDD+ policies and measures. The monitoring system will work as a platform to obtain information on their REDD+ results and actions, related directly or indirectly to national REDD+ strategies and may also include actions unrelated to carbon assessment, such as forest law enforcement. With the technical assistance of FAO, INPE and other stakeholders, the countries will set up an autonomous operational forest monitoring system. An initial version and the methodologies of the system for DRC and PNG has been launched in Durban, South Africa during COP 17 and in 2012 Paraguay, Viet Nam and Zambia will be launched in Doha, Qatar at COP 18. The access to high-quality satellite data for these countries is crucial for the set-up.

Jonckheere, I. G.

2012-12-01

328

Application prospects of survey satellite imaging for geodinamics observating  

Microsoft Academic Search

Block structures is problem of earth crust and which can display in satellite supervisions. The theoretical substantiation of blocks vertical movements and earth crust (dimension < 140x140km) to influence on topography of ocean surface is given. That anomalies investigated satellite altimetry methods. Blocks inclinations (dimension < 140x140km) to influence of vertical movements air (inside atmosphere), it is discussed. They are

I. L. Uchytel; V. N. Yaroshenko; I. I. Gladkykh; B. B. Kapochkin

2004-01-01

329

Observation of laser satellites in a plasma produced by a femtosecond laser pulse  

E-print Network

Observation of laser satellites in a plasma produced by a femtosecond laser pulse S. A. Pikuz P. N­459 10 October 1997 Laser satellites are detected in the emission spectra of magnesium and aluminum they called laser satellites, should appear in the emission spectrum of an ion placed in a strong laser field

Umstadter, Donald

330

A general interactive system for compositing digital radar and satellite data  

NASA Technical Reports Server (NTRS)

Reynolds and Smith (1979) have considered the combined use of digital weather radar and satellite data in interactive systems for case study analysis and forecasting. Satellites view the top of clouds, whereas radar is capable of observing the detailed internal structure of clouds. The considered approach requires the use of a common coordinate system. In the present investigation, it was decided to use the satellite coordinate system as the base system in order to maintain the fullest resolution of the satellite data. The investigation is concerned with the development of a general interactive software system called RADPAK for remapping and analyzing conventional and Doppler radar data. RADPAK is implemented as a part of a minicomputer-based image processing system, called Atmospheric and Oceanographic Image Processing System. Attention is given to a general description of the RADPAK system, remapping methodology, and an example of satellite remapping.

Ghosh, K. K.; Chen, L. C.; Faghmous, M.; Heymsfield, G. M.

1981-01-01

331

Satellite power system (SPS) public outreach experiment  

SciTech Connect

To improve the results of the Satellite Power System (SPS) Concept Development and Evaluation Program, an outreach experiment was conducted. Three public interest groups participated: the L-5 Society (L-5), Citizen's Energy Project (CEP), and the Forum for the Advancement of Students in Science and Technology (FASST). Each group disseminated summary information about SPS to approximately 3000 constituents with a request for feedback on the SPS concept. The objectives of the outreach were to (1) determine the areas of major concern relative to the SPS concept, and (2) gain experience with an outreach process for use in future public involvement. Due to the combined efforts of all three groups, 9200 individuals/organizations received information about the SPS concept. Over 1500 receipients of this information provided feedback. The response to the outreach effort was positive for all three groups, suggesting that the effort extended by the SPS Project Division to encourage an information exchange with the public was well received. The general response to the SPS differed with each group. The L-5 position is very much in favor of SPS; CEP is very much opposed and FASST is relatively neutral. The responses are analyzed, and from the responses some questions and answers about the satellite power system are presented in the appendix. (WHK)

McNeal, S.R.

1980-12-01

332

Differential satellite laser ranging as a system calibration tool  

Microsoft Academic Search

We are presenting a new satellite laser ranging technique. The Differential Satellite Laser Ranging (DSLR) is a technique providing highly accurate short ground baselines and relative station heights. Two satellite laser ranging systems are sharing one common laser transmitter. Recording the echo pulses arrival times at different locations, the corresponding baseline and relative station height may be evaluated. Due to

Ivan Prochazka; Karel Hamal; Josef Blazej

2002-01-01

333

Cost-driven design of small satellite remote sensing systems  

Microsoft Academic Search

Earth remote sensing (alongside communications) is one of the key application of Earth-orbiting satellites. Civilian satellites in the LANDSAT and SPOT series provide Earth images which have been used for a vast spectrum of applications in agriculture, meteorology, hydrology, urban planning and geology, to name but a few. In the defence sector, satellite remote sensing systems are a critical tool

Marc Fouquet; Jeff Ward

1998-01-01

334

SORCE and Future Satellite Observations of Solar Irradiance  

NASA Technical Reports Server (NTRS)

With solar activity just passing the maximum of cycle 23, SORCE is beginning a 5 year mission to measure total solar irradiance (TSI) with unprecedented accuracy using phase-sensitive detection, and to measure spectral solar irradiance (SSI) with unprecedented spectral coverage, from 1 to 2000 nm. The new Total Irradiance Monitor (TIM) has 4 active cavity radiometers, any one of which can be used as a fixed-temperature reference against any other that is exposed to the Sun via a shutter that cycles at a rate designed to minimize noise at the shutter frequency. The new Spectral Irradiance Monitor (SIM) is a dual Fery prism spectrometer that can employ either prism as a monochromatic source on the other prism, thus monitoring its transmission during the mission lifetime. Either prism can measure SSI from 200 to 2000 nm, employing the same phase-sensitive electrical substitution strategy as TIM. SORCE also carries dual SOLSTICE instruments to cover the spectral range 100-320 nm, similar to the instruments onboard UARS, and also an XUV Photometer System (XPS) similar to that on TIMED. SSI has now been added to TSI as a requirement of EOS and NPOESS, because different spectral components drive different components of the climate system - UV into upper atmosphere and stratospheric ozone, IR into tropospheric water vapor and clouds, and Visible into the oceans and biosphere. Succeeding satellite missions being planned for 2006 and 2011 will continue to monitor these critical solar variables.

Cahalan, Robert F.; Rottman, G.; Woods, T.; Lawrence, G.; Kopp, G.; Harder, J.; McClintock, W.

2003-01-01

335

Satellite based Global Flood Detection System - strengths and limitations  

NASA Astrophysics Data System (ADS)

One of the main problems for global hydrological models is that for many regions only very limited or no observational data for a model assessment is available. This problem could be overcome with filling the gaps using information derived from satellite observations. Thus, an evaluation of the remote sensing signal of the Global Flood Detection System (GFDS) against observed discharge data was performed in order to test the use of this data in sparsely gauged river basins. The study was carried out at 398 locations near the main rivers and in Africa, Asia, Europe, North America and South America. After evaluating different methodologies for extracting the satellite signal, a temporal (4 days) and spatial (4 GFDS pixels) average was chosen to proceed with the analysis. For the 340 stations with a concurrent time series longer than seven years for both, the signal and the in situ observed discharge (obtained mainly from the Global Runoff Data Centre), a calibration based on monthly linear models was carried out. The validation was executed and several skill scores were calculated such as the R2, Nash-Sutcliffe (NSE), and Root Mean Square Error (RMSE). It is important to highlight that, for this study, 230 stations globally had Nash-Sutcliffe efficient score higher than zero, indicating that for specific conditions the satellite signal as used in GFDS can fill the gaps where observations are not available. For example, several locations in African catchments have good performance as in the Niger, Volta and Zambezi for which Nash-Sutcliffe is greater than 0.75. It is known that a number of factors affect total upwelling microwave brightness from a mixed water and land surface measured by a single image pixel. Aiming to better understand how some features of the sites could affect the satellite signal and the correlation with in situ observations, apart from the dependency on the river geometry, a multivariate analysis was carried out between the skill scores (NSE and R2) obtained from the validation and the local characteristics of the site. The potential affecting factors that were studied were the land cover, leaf area index, climatic areas, the flood extent maps, mean runoff, presence of dams and permafrost layer, as well as the upstream area. Results showed that many of the stations which received poor skills scores were due to low flow conditions. Importance of the outstanding local characteristics affecting will be explained. The work undertaken provide us with a better understanding of the impact of the local conditions on the performance of the satellite signal and give us guidance on the best locations and limitations for estimating discharge values from daily satellite signal.

Revilla-Romero, Beatriz; Salamon, Peter; Thielen, Jutta; De Groeve, Tom; Zajac, Zuzanna

2014-05-01

336

Space Weathering on Icy Satellites in the Outer Solar System  

NASA Astrophysics Data System (ADS)

Space weathering produces well-known optical effects in silicate minerals in the inner Solar System, for example, on the Moon. Space weathering from solar wind and UV is expected to be weaker in the outer Solar System simply because intensities are lower. However, cosmic rays from inner to outer solar system would be similar to first order. Similarly with micrometeoroid bombardment. That, combined with the much higher volatility of icy surfaces means there is the potential for space weathering on icy outer Solar System surfaces to show optical effects. The Cassini spacecraft orbiting Saturn is providing evidence for space weathering on icy bodies. The Cassini VIMS instrument has spatially mapped satellite surfaces and the rings from .35-5 microns and the UVIS instrument from 0.1 to 0.2 microns. These data have sampled a complex mixing space between H2O ice and non-ice components and they show some common spectral properties. Similarly, spectra of the icy Galilean satellites and satellites in the Uranian system have some commonality in spectral properties with those in the Saturn system. The UV absorber is spectrally similar on many surfaces. VIMS has identified CO2, H2 and trace organics in varying abundances on Saturn's satellites. We postulate that through the spatial relationships of some of these compounds that they are created and destroyed through space weathering effects. For example, the trapped H2 and CO2 observed by VIMS in regions with high concentrations of dark material may in part be space weathering products from the destruction of H2O and organic molecules. The dark material, particularly on Iapetus which has the highest concentration in the Saturn system, is well matched by space-weathered silicates in the .4-2.6 micron range, and the spectral shapes closely match those of the most mature lunar soils, another indicator of space weathered material.

Clark, Roger N.; Perlman, Zachary; Pearson, Neil; Cruikshank, Dale P.

2014-11-01

337

Engineering calculations for communications satellite systems planning  

NASA Technical Reports Server (NTRS)

A procedure is described that was used to calculate minimum required satellite separations based on total link carrier to interference requirements. Also summarized are recent results with a switching algorithm for satellite synthesis problems. Analytic solution value bounds for two of the satellite synthesis models studied are described. Preliminary results from an empirical study of alternate mixed integer programming models for satellite synthesis are presented. Research plans for the near future are discussed.

Reilly, Charles H.; Walton, Eric K.; Kohnhorst, Paul

1987-01-01

338

First Satellite Observations of Lower Tropospheric Ammonia and Methanol  

NASA Technical Reports Server (NTRS)

The Tropospheric Emission Spectrometer (TES) on the EOS Aura satellite makes global measurements of infrared radiances which are used to derive profiles of species such as O3, CO, H2O, HDO and CH4 as routine standard products. In addition, TES has a variety of special modes that provide denser spatial mapping over a limited geographical area. A continuous-coverage mode (called ''transect'', about 460 km long) has now been used to detect additional molecules indicative of regional air pollution. On 10 July 2007 at about 05:37 UTC (13:24 LMST) TES conducted such a transect observation over the Beijing area in northeast China. Examination of the residual spectral radiances following the retrieval of the TES standard products revealed surprisingly strong features attributable to enhanced concentrations of ammonia (NH3) and methanol (CH3OH), well above the normal background levels. This is the first time that these molecules have been detected in space-based nadir viewing measurements that penetrate into the lower atmosphere.

Beer, Reinhard; Shephard, Mark W.; Kulawik, Susan S.; Clough, Shepard A.; Eldering, Annmarie; Bowman, Kevin W.; Sander, Stanley P.; Fisher, Brendan M.; Payne, Vivienne H.; Luo, Mingzhao; Osterman, Gregory B.; Worden, John R.

2008-01-01

339

Satellite observations of oil spills in Bohai Sea  

NASA Astrophysics Data System (ADS)

Several oil spills occurred at two oil platforms in Bohai Sea, China on June 4 and 17, 2011. The oil spills were subsequently imaged by different types of satellite sensors including SAR (Synthetic Aperture Radar), Chinese HJ-1-B CCD and NOAA MODIS. In order to detect the oil spills more accurately, images of the former three sensors were used in this study. Oil spills were detected using the semi-supervised Texture-Classifying Neural Network Algorithm (TCNNA) in SAR images and gradient edge detection algorithm in HJ-1-B and MODIS images. The results show that, on June 11, the area of oil slicks is 31 km2 and they are observed in the vicinity and to the north of the oilfield in SAR image. The coverage of the oil spill expands dramatically to 244 km2 due to the newly released oil after June 11 in SAR image of June 14. The results on June 19 show that under a cloud-free condition, CCD and MODIS images capture the oil spills clearly while TCNNA cannot separate them from the background surface, which implies that the optical images play an important role in oil detection besides SAR images.

Wei, Y. L.; Tang, Z. Y.; Li, X. F.

2014-03-01

340

Rates of Horizontal Tau Air-Showers observable by satellites  

E-print Network

Up-going and Horizontal Tau Air-Showers, UpTaus and HorTaus, may trace Ultra High Energy Neutrino Tau Earth Skimming at the edge of the horizon. We show that such events even for minimal GZK neutrino fluxes could be detected by space telescopes such as the EUSO project. These Horizontal Tau Showers will track very long fan-like, multi-finger showers whose signature would be revealed by EUSO, OWL experiments. Moreover the additional imprint of their young secondaries muon, electron pairs and gamma bundles flashes might allow to disentangle their nature from the older UHECR secondaries in horizontal showers. Indeed at large zenith angles, the muon, electron pairs and gamma number for far and old Ultra High Energy Cosmic Rays, becomes comparable. On the contrary up-ward muon bundles from UpTaus and HorTaus (as well as by anti-neutrino electron + electron resonance at Glashow peak) may arise within a young shower with a gamma-muon ratio as large as 10^2. Such a very characteristic imprint maybe observed by Crown detector arrays on Mountain, planes or balloons in space, as well as by gamma satellites in Space. We estimate the UpTaus and HorTaus rate from the Earth and the consequent event rate of +/-mu bundles, whose flux at 92^o -97^o may exceed the up-going muon flux induced by the atmospheric neutrino, by one or two order of magnitude.

D. Fargion; M. Grossi; M. De Santis; P. G. de Sanctis Lucentin

2005-01-03

341

Analysis of Satellite-Based Polar Mesospheric Cloud Observations  

NASA Astrophysics Data System (ADS)

Polar Mesospheric Clouds (PMCs) are thin water-ice clouds that form in the summer polar mesopause region. Since PMCs are sensitive to changes in the upper atmospheric temperature and water vapor abundance, they can be used to understand the dynamics of the upper mesosphere. It has also been suggested that they are important indicators of mesospheric climate change. PMCs have been successfully observed from the ground and with remote sensing instruments, for example the Cloud Imaging and Particle Size (CIPS) experiment on the Aeronomy of Ice in the Mesosphere (AIM) satellite, and the Solar Backscatter UltraViolet (SBUV) instruments. This thesis presents validation of CIPS observations by showing a comparison of PMC occurrence frequency, cloud and background albedo as observed by CIPS and SBUV. It is found that frequency and cloud albedo are in excellent agreement, with a small (10%) low bias in the CIPS v3.20 operational frequencies at more equatorward PMC latitudes on the descending node. The background albedo, however, shows a still unresolved bias that depends on hemisphere. Overall, the results show that CIPS PMC data are valid for scientific analysis. Furthermore, this thesis investigates and quantifies the relative importance of several coupling mechanisms that contribute to variability in the PMC season onset, such as the solar cycle and intra-hemispheric and inter-hemispheric coupling. It is found that the Southern Hemisphere (SH) PMC season onset is controlled primarily by the timing of the SH stratospheric wind reversal from its winter to summer state, with a smaller but still important contribution from the solar cycle. Inter-hemispheric coupling triggered by winter stratospheric wind variations plays a significant role in controlling the Northern Hemisphere (NH) PMC season onset dates, again with additional control by the solar cycle. These couplings explain most of the observed variability in the PMC onset dates as observed by SBUV over the past three decades. Preliminary results indicate that the Specified Dynamics version of the Whole Atmosphere Community Climate Model (SD-WACCM) will be a useful tool for more detailed studies of the mechanisms that control PMC variability. Future studies extending the presented CIPS validation and PMC variability investigation are suggested.

Benze, Susanne

342

Observability of complex systems  

PubMed Central

A quantitative description of a complex system is inherently limited by our ability to estimate the system’s internal state from experimentally accessible outputs. Although the simultaneous measurement of all internal variables, like all metabolite concentrations in a cell, offers a complete description of a system’s state, in practice experimental access is limited to only a subset of variables, or sensors. A system is called observable if we can reconstruct the system’s complete internal state from its outputs. Here, we adopt a graphical approach derived from the dynamical laws that govern a system to determine the sensors that are necessary to reconstruct the full internal state of a complex system. We apply this approach to biochemical reaction systems, finding that the identified sensors are not only necessary but also sufficient for observability. The developed approach can also identify the optimal sensors for target or partial observability, helping us reconstruct selected state variables from appropriately chosen outputs, a prerequisite for optimal biomarker design. Given the fundamental role observability plays in complex systems, these results offer avenues to systematically explore the dynamics of a wide range of natural, technological and socioeconomic systems. PMID:23359701

Liu, Yang-Yu; Slotine, Jean-Jacques; Barabási, Albert-László

2013-01-01

343

SAW based systems for mobile communications satellites  

NASA Technical Reports Server (NTRS)

Modern mobile communications satellites, such as INMARSAT 3, EMS, and ARTEMIS, use advanced onboard processing to make efficient use of the available L-band spectrum. In all of these cases, high performance surface acoustic wave (SAW) devices are used. SAW filters can provide high selectivity (100-200 kHz transition widths), combined with flat amplitude and linear phase characteristics; their simple construction and radiation hardness also makes them especially suitable for space applications. An overview of the architectures used in the above systems, describing the technologies employed, and the use of bandwidth switchable SAW filtering (BSSF) is given. The tradeoffs to be considered when specifying a SAW based system are analyzed, using both theoretical and experimental data. Empirical rules for estimating SAW filter performance are given. Achievable performance is illustrated using data from the INMARSAT 3 engineering model (EM) processors.

Peach, R. C.; Miller, N.; Lee, M.

1993-01-01

344

Inferring CO2 sources and sinks from satellite observations: Method and application to TOVS data  

NASA Astrophysics Data System (ADS)

Properly handling satellite data to constrain the inversion of CO2 sources and sinks at the Earth surface is a challenge motivated by the limitations of the current surface observation network. In this paper we present a Bayesian inference scheme to tackle this issue. It is based on the same theoretical principles as most inversions of the flask network but uses a variational formulation rather than a pure matrix-based one in order to cope with the large amount of satellite data. The minimization algorithm iteratively computes the optimum solution to the inference problem as well as an estimation of its error characteristics and some quantitative measures of the observation information content. A global climate model, guided by analyzed winds, provides information about the atmospheric transport to the inversion scheme. A surface flux climatology regularizes the inference problem. This new system has been applied to 1 year's worth of retrievals of vertically integrated CO2 concentrations from the Television Infrared Observation Satellite Operational Vertical Sounder (TOVS). Consistent with a recent study that identified regional biases in the TOVS retrievals, the inferred fluxes are not useful for biogeochemical analyses. In addition to the detrimental impact of these biases, we find a sensitivity of the results to the formulation of the prior uncertainty and to the accuracy of the transport model. Notwithstanding these difficulties, four-dimensional inversion schemes of the type presented here could form the basis of multisensor data assimilation systems for the estimation of the surface fluxes of key atmospheric compounds.

Chevallier, F.; Fisher, M.; Peylin, P.; Serrar, S.; Bousquet, P.; BréOn, F.-M.; ChéDin, A.; Ciais, P.

2005-12-01

345

The Variation of Tropical Cyclone Rainfall within the North Atlantic and Pacific as Observed from Satellites  

NASA Technical Reports Server (NTRS)

Tropical cyclone monthly rainfall amounts are estimated from passive microwave satellite observations in the North Atlantic and in three equal geographical regions of the North Pacific (i.e., Western, Central, and Eastern North Pacific). These satellite-derived rainfall amounts are used to assess the impact of tropical cyclone rainfall in altering the geographical, seasonal, and inter-annual distribution of the 1987-1989, 1991-1998 North Atlantic and Pacific rainfall during June-November when tropical cyclones are most abundant. To estimate these tropical cyclone rainfall amounts, mean monthly rain rates are derived from the Defence Meteorological Satellite Program (DMSP) Special Sensor Microwave/ Radiometer (SSM/I) observations within 444 km radius of the center of those North Atlantic and Pacific tropical cyclones that reached storm stage and greater. These rain rate observations are then multiplied by the number of hours in a given month. Mean monthly rainfall amounts are also constructed for all the other North Atlantic and Pacific raining systems during this eleven year period for the purpose of estimating the geographical distribution and intensity of rainfall contributed by non-tropical cyclone systems. Further, the combination of the non-tropical cyclone and tropical cyclone (i.e., total) rainfall is constructed to delineate the fractional amount that tropical cyclones contributed to the total North Pacific rainfall.

Rodgers, Edward; Pierce, Harold; Adler, Robert

1999-01-01

346

Current Sounding Capability From Satellite Meteorological Observation With Ultraspectral Infrared Instruments  

NASA Technical Reports Server (NTRS)

Ultraspectral resolution infrared spectral radiance obtained from near nadir observations provide atmospheric, surface, and cloud property information. The intent of the measurement of tropospheric thermodynamic state and trace abundances is the initialization of climate models and the monitoring of air quality. The NPOESS Airborne Sounder Testbed-Interferometer (NAST-I), designed to support the development of future satellite temperature and moisture sounders, aboard high altitude aircraft has been collecting data throughout many field campaigns. An advanced retrieval algorithm developed with NAST-I is now applied to satellite data collected with the Atmospheric InfraRed Sounder (AIRS) on the Aqua satellite launched on 4 May 2002 and the Infrared Atmospheric Sounding Interferometer (IASI) on the MetOp satellite launched on October 19, 2006. These instruments possess an ultra-spectral resolution, for example, both IASI and NAST-I have 0.25 cm-1 and a spectral coverage from 645 to 2760 cm-1. The retrieval algorithm with a fast radiative transfer model, including cloud effects, is used for atmospheric profile and cloud parameter retrieval. The physical inversion scheme has been developed, dealing with cloudy as well as cloud-free radiance observed with ultraspectral infrared sounders, to simultaneously retrieve surface, atmospheric thermodynamic, and cloud microphysical parameters. A fast radiative transfer model, which applies to the clouded atmosphere, is used for atmospheric profile and cloud parameter retrieval. A one-dimensional (1-d) variational multi-variable inversion solution is used to improve an iterative background state defined by an eigenvector-regression-retrieval. The solution is iterated in order to account for non-linearity in the 1-d variational solution. It is shown that relatively accurate temperature and moisture retrievals can be achieved below optically thin clouds. For optically thick clouds, accurate temperature and moisture profiles down to cloud top level are obtained. For both optically thin and thick cloud situations, the cloud top height can be retrieved with relatively high accuracy (i.e., error less than 1 km). Retrievals of atmospheric soundings, surface properties, and cloud microphysical properties with the AIRS and IASI observations are obtained and presented. These retrievals are further inter-compared with those obtained from airborne FTS system, such as the NPOESS Airborne Sounder Testbed? Interferometer (NAST I), dedicated dropsondes, radiosondes, and ground based Raman Lidar. The capabilities of satellite ultra-spectral sounder such as the AIRS and IASI are investigated. These advanced satellite ultraspectral infrared instruments are now playing an important role in satellite meteorological observation for numerical weather prediction.

Zhou, Daniel K.; Liu, Xu; Larar, Allen M.

2008-01-01

347

New Constraints on Additional Satellites of the Pluto System  

E-print Network

Observations of Pluto and its solar-tidal stability zone were made using the Advanced Camera for Surveys' (ACS) Wide Field Channel (WFC) on the Hubble Space Telescope on UT 2005 May 15 and UT 2005 May 18. Two small satellites of Pluto, provisionally designated S/2005 P 1 and S/2005 P 2, were discovered, as discussed by Weaver et al. (2006) and Stern et al. (2006a). Confirming observations of the newly discovered moons were obtained using the ACS in the High Resolution Channel (HRC) mode on 2006 Feb 15 (Mutchler et al. 2006). Both sets of observations provide strong constraints on the existence of any additional satellites in the Pluto system. Based on the May 2005 observations using the ACS/WFC, we place a 90%-confidence lower limit of m_V = 26.8 (m_V = 27.4 for a 50%-confidence lower limit) on the magnitude of undiscovered satellites greater than 5" (1.1x10^5 km) from Pluto. Using the 2005 Feb 15 ACS/HRC observations we place 90%-confidence lower limits on the apparent magnitude of any additional satellites of m_V = 26.4 between 3"-5" (6.9x10^4-1.1x10^5 km) from Pluto, m_V = 25.7 between 1"-3" (2.3x10^4-6.9x10^4 km) from Pluto, and m_V = 24. between 0.3"-1" (6.9x10^3-2.3x10^4 km) from Pluto. The 90%-confidence magnitude limits translate into upper limits on the diameters of undiscovered satellites of 29 km outside of 5" from Pluto, 36 km between 3"-5" from Pluto, 49 km between 1"-3" from Pluto, and 115 km between 0.3"-1" for a comet-like albedo of p_V = 0.04. If potential satellites are assumed to have a Charon-like albedo of p_V = 0.38, the diameter limits are 9 km, 12 km, 16 km, and 37 km, respectively.

A. J. Steffl; M. J. Mutchler; H. A. Weaver; S. A. Stern; D. D. Durda; D. Terrell; W. J. Merline; L. A. Young; E. F. Young; M. W. Buie; J. R. Spencer

2005-11-30

348

Detailed Analysis of Indian Summer Monsoon Rainfall Processes with Modern/High-Quality Satellite Observations  

NASA Technical Reports Server (NTRS)

We examine, in detail, Indian Summer Monsoon rainfall processes using modernhigh quality satellite precipitation measurements. The focus here is on measurements derived from three NASA cloud and precipitation satellite missionslinstruments (TRMM/PR&TMI, AQUNAMSRE, and CLOUDSATICPR), and a fourth TRMM Project-generated multi-satellite precipitation measurement dataset (viz., TRMM standard algorithm 3b42) -- all from a period beginning in 1998 up to the present. It is emphasized that the 3b42 algorithm blends passive microwave (PMW) radiometer-based precipitation estimates from LEO satellites with infi-ared (IR) precipitation estimates from a world network of CEO satellites (representing -15% of the complete space-time coverage) All of these observations are first cross-calibrated to precipitation estimates taken from standard TRMM combined PR-TMI algorithm 2b31, and second adjusted at the large scale based on monthly-averaged rain-gage measurements. The blended approach takes advantage of direct estimates of precipitation from the PMW radiometerequipped LEO satellites -- but which suffer fi-om sampling limitations -- in combination with less accurate IR estimates from the optical-infrared imaging cameras on GEO satellites -- but which provide continuous diurnal sampling. The advantages of the current technologies are evident in the continuity and coverage properties inherent to the resultant precipitation datasets that have been an outgrowth of these stable measuring and retrieval technologies. There is a wealth of information contained in the current satellite measurements of precipitation regarding the salient precipitation properties of the Indian Summer Monsoon. Using different datasets obtained from the measuring systems noted above, we have analyzed the observations cast in the form of: (1) spatially distributed means and variances over the hierarchy of relevant time scales (hourly I diurnally, daily, monthly, seasonally I intra-seasonally, and inter-annually), (2) time series at these different time scales taken as area-averages over the hierarchy of relevant space scales (Indian sub-Division, Indian sub-continent, and Circumambient Indian Ocean), (3) principal autocorrelation and cross-correlation structures over various monsoon space-time domains, (4) diurnally modulated amplitude-phase properties of rain rates over different monsoon space-time domains, (5) foremost rain rate probability distributions intrinsic to monsoon precipitation, and (6) behavior of extreme events including occurrences of flood and drought episodes throughout the course of inter-annual monsoon processes.

Smith, Eric A.; Kuo, Kwo-Sen; Mehta, Amita V.; Yang, Song

2007-01-01

349

Jupiter System Observer  

NASA Technical Reports Server (NTRS)

This slide presentation reviews the scientific philosophy that is guiding the planning behind the Jupiter System Observer (JSO). The JSO would be a long-term platform for studying Jupiter and the complete Jovian system. The goal is to advance the understanding of the fundamental processes of planetary systems, their formation and evolution.

Senske, Dave; Prockter, Louise

2008-01-01

350

Power line harmonic radiation observed by satellite: Properties and propagation through the ionosphere  

E-print Network

Power line harmonic radiation observed by satellite: Properties and propagation through of power line harmonic radiation events observed by the low-altitude DEMETER spacecraft. Altogether, 88. Santoli´k, M. Parrot, and J. Bortnik (2008), Power line harmonic radiation observed by satellite

Santolik, Ondrej

351

Mobile satellite communications systems: Toward global personal communications  

Microsoft Academic Search

The constraints imposed by the RF environment are reviewed. An overview of present and planned mobile satellite systems is given. Present systems refer to those already in operation, while planned systems refer to those that have authority to offer the services and have either a satellite in orbit or one being built to support the systems. Future directions for mobile

John H. Lodge

1991-01-01

352

Irregular Satellites of the Planets: Products of Capture in the Early Solar System  

E-print Network

All four giant planets in the Solar system possess irregular satellites, characterized by large, highly eccentric and/or inclined orbits that are distinct from the nearly circular, uninclined orbits of the regular satellites. This difference can be traced directly to different modes of formation. Whereas the regular satellites grew by accretion within circumplanetary disks the irregular satellites were captured from initially heliocentric orbits at an early epoch. Recently, powerful survey observations have greatly increased the number of known irregular satellites, permitting a fresh look at the group properties of these objects and motivating a re-examination of the mechanisms of capture. None of the suggested mechanisms, including gas-drag, pull-down, and three-body capture, convincingly fit the group characteristics of the irregular satellites. The sources of the satellites also remain unidentified.

David Jewitt; Nader Haghighipour

2007-03-03

353

Satellite Observations of the Effect of Natural and Anthropogenic Aerosols on Clouds  

NASA Technical Reports Server (NTRS)

Our knowledge of atmospheric aerosols (smoke, pollution, dust or sea salt particles, small enough to be suspended in the air), their evolution, composition, variability in space and time and interaction with clouds and precipitation is still lacking despite decades of research. Understanding the global aerosol system is critical to quantifying anthropogenic climate change, to determine climate sensitivity from observations and to understand the hydrological cycle. While a single instrument was used to demonstrate 50 years ago that the global CO2 levels are rising, posing threat of global warming, we need an array of satellites and field measurements coupled with chemical transport models to understand the global aerosol system. This complexity of the aerosol problem results from their short lifetime (1 week) and variable chemical composition. A new generation of satellites provides exciting opportunities to measure the global distribution of aerosols, distinguishing natural from anthropogenic aerosol and measuring their interaction with clouds and climate.

Kaufman, Yoram J.

2006-01-01

354

Retrofitting a fine-pointing system to satellite optics  

SciTech Connect

This paper describe a system that was added to an existing satellite-borne telescope design for the purpose of compensating the boresight errors that had been observed in earlier flights of similar instruments. Those errors had been found to be caused by thermal distortion of the spaceframe. This retrofit design was subject to severe volume restrictions because it was fitted into an already tightly-packaged instrument envelope. It was found practical to improve the basic design by converting a redundant structure into a statically-determinate one. It was also possible to use portions of the mechanical actuation system to facilitate the position encoding needed for computer interfacing.

Woods, R.O.

1994-12-31

355

Retrofitting a fine-pointing system to satellite optics  

NASA Technical Reports Server (NTRS)

This paper describes a system added to an existing satellite-borne telescope design for the purpose of compensating the boresight errors that had been observed in earlier flights of similar instruments. Those errors had been found to be caused by thermal distortion of the spaceframe. This retrofit design was subjected to severe volume restrictions because it was fitted into an already tightly-packaged instrument envelope. It was found practical to improve the basic design by converting a redundant structure into a statically-determinate one. It was also possible to use portions of the mechanical actuation system to facilitate the position encoding needed for computer interfacing.

Woods, Robert O.

1995-01-01

356

Improved monitoring of surface ozone by joint assimilation of geostationary satellite observations of ozone and CO  

NASA Astrophysics Data System (ADS)

Future geostationary satellite observations of tropospheric ozone aim to improve monitoring of surface ozone air quality. However, ozone retrievals from space have limited sensitivity in the lower troposphere (boundary layer). Data assimilation in a chemical transport model can propagate the information from the satellite observations to provide useful constraints on surface ozone. This may be aided by correlated satellite observations of carbon monoxide (CO), for which boundary layer sensitivity is easier to achieve. We examine the potential of concurrent geostationary observations of ozone and CO to improve constraints on surface ozone air quality through exploitation of ozone-CO model error correlations in a joint data assimilation framework. The hypothesis is that model transport errors diagnosed for CO provide information on corresponding errors in ozone. A paired-model analysis of ozone-CO error correlations in the boundary layer over North America in summer indicates positive error correlations in continental outflow but negative regional-scale error correlations over land, the latter reflecting opposite sensitivities of ozone and CO to boundary layer depth. Aircraft observations from the ICARTT campaign are consistent with this pattern but also indicate strong positive error correlations in fine-scale pollution plumes. We develop a joint ozone-CO data assimilation system and apply it to a regional-scale Observing System Simulation Experiment (OSSE) of the planned NASA GEO-CAPE geostationary mission over North America. We find substantial benefit from joint ozone-CO data assimilation in informing US ozone air quality if the instrument sensitivity for CO in the boundary layer is greater than that for ozone. A high-quality geostationary measurement of CO could potentially relax the requirements for boundary layer sensitivity of the ozone measurement. This is contingent on accurate characterization of ozone-CO error correlations. A finer-resolution data assimilation system resolving the urban scale would need to account for the change in sign of the ozone-CO error correlations between urban pollution plumes and the regional atmosphere.

Zoogman, Peter; Jacob, Daniel J.; Chance, Kelly; Worden, Helen M.; Edwards, David P.; Zhang, Lin

2014-02-01

357

Mars Operational Environmental Satellite (MOES): A post-Mars Observer discovery mission  

NASA Technical Reports Server (NTRS)

Mars Operational Environmental Satellite (MOES) is a Discovery concept mission that is designed to observe the global short-term weather phenomena on Mars in a systematic fashion. Even after the Mariner, Viking, and, soon, Mars Observer missions, crucial aspects of the martian atmosphere will remain unobserved systematically. Achieving a better understanding of the cycles of dust, water vapor, and ices on Mars requires detailed information about atmospheric transports of those quantities associated with the weather systems, particularly those arising in mid latitudes during fall and winter. It also requires a quantitive understanding of the processes responsible for the onset and evolution of dust storms on all scales. Whereas on Earth the system of geosynchronous and polar orbiting satellites provides continuous coverage of the weather systems, on Mars the time history of important events such as regional and global dust storms remains unobserved. To understand the transport of tracers in the martian atmosphere and particularly to identify their sources and sinks, it is necessary to have systematic global, synoptic observations that have yet to be attained. Clearly these requirements are not easy to achieve from a single spacecraft in orbit, but if we focus on specific regions of the planet, e.g., polar vs. low and mid latitudes, then it is possible to attain a nearly ideal coverage at a reasonable spatial and temporal resolution with a system of just two satellites. Mars Observer is about to yield good coverage of the polar latitudes, so we focus initially on the region not covered well in terms of diurnal coverage, and in terms of desired observations will provide the initial data for the numerical models of the martian weather and climate that can be verified only with better temporal and spatial data.

Limaye, Sanjay S.

1993-01-01

358

MY NASA DATA Lesson Plan: Storm Clouds-Fly over a Late Winter Storm onboard a NASA Earth Observing Satellite  

NSDL National Science Digital Library

: This lesson plan uses Clouds and Earth's Radiant Energy System (CERES) cloud data and a weather map to explore cloud coverage during a winter storm. When atmospheric scientists, including meteorologists, study weather patterns, they may use several different sources of information. For example, in studying storm patterns, they may use a combination of Earth Observing Satellite data, such as from CERES, or NOAA weather satellite imagery, and geographical tools to determine locations and paths of storms. As one part of the training to analyze this data and imagery, scientists look at 'case studies' such as the late winter storm shown in the weather satellite imagery included with the lesson. An infrared satellite image looks at the temperature. Cold things (like high clouds) are very bright. Warm things (like Mexico and Florida) are dark. The imagery can be compared to data collected by other satellites, so that improved models of storm patterns can be developed.

2006-01-01

359

North American mobile satellite system signaling architecture  

NASA Astrophysics Data System (ADS)

Some of the signaling requirements for the mobile satellite system (MSS) along with the overall signaling architecture are presented, with emphasis on certain particular aspects of the mobile-earth-terminal(MET)-group-controller(GC) signaling channels. Outbound (GC to MET) TDM channels are used to transmit frequency assignments as well as network status information to METs. Inbound TDMA channels are used by the METs to respond to call announcements and status queries sent by the GC. Inbound (MET and GC) random access channels that employ a sloppy slotted aloha approach to synchronization are used by the METs to initiate calls. The basic structure and function of each of these channels is described. The synchronization issues associated with the inbound slotted aloha and TDMA channels are discussed. The loading and congestion control strategy developed for the random access channels is presented.

White, Lawrence; Agarwal, Anil; Skerry, Brian; Tisdale, Bill

1992-03-01

360

Ionospheric electron density irregularities observed by satellite-to-satellite, dual-frequency, low-low Doppler tracking link  

NASA Technical Reports Server (NTRS)

A low-low, satellite-to-satellite, dual-frequency, Doppler tracking experiment was performed. The data are analyzed here for irregularities in electron density at the altitude of 212 km. The differential Doppler data with the relative motion term removed are integrated to obtain a representation of the electron density variation along the satellite path. Well-known large-scale features such as the equatorial geomagnetic anomaly and day/night ionization level differences are clearly observed in the integrated data. The larger crest of the morning geomagnetic anomaly is seen to occur in the southern (winter) hemisphere in agreement with previous observations. In addition, a sharp peak in the electron density at the day-to-night transition point is observed in two consecutive revolutions. This effect may be due to the previously postulated atmospheric shock wave generated by supersonic motion of the terminator.

Estes, R. D.; Grossi, M. D.

1984-01-01

361

Retrieval of Aerosol Absorption Properties from Satellite Observations  

NASA Technical Reports Server (NTRS)

The Angstrom Absorption Exponent (AAE) is a parameter commonly used to characterize the wavelength-dependence of aerosol absorption optical depth (AAOD). It is closely related to aerosol composition. Black carbon (BC) containing aerosols yield AAE values near unity whereas Organic carbon (OC) aerosol particles are associated with values larger than 2. Even larger AAE values have been reported for desert dust aerosol particles. Knowledge of spectral AAOD is necessary for the calculation of direct radiative forcing effect of aerosols and for inferring aerosol composition. We have developed a satellitebased method of determining the spectral AAOD of absorbing aerosols. The technique uses multi-spectral measurements of upwelling radiation from scenes where absorbing aerosols lie above clouds as indicated by the UV Aerosol Index. For those conditions, the satellite measurement can be explained, using an approximations of Beer's Law (BL), as the upwelling reflectance at the cloud top attenuated by the absorption effects of the overlying aerosol layer. The upwelling reflectance at the cloud-top in an aerosol-free atmospheric column is mainly a function of cloud optical depth (COD). In the proposed method of AAE derivation, the first step is determining COD which is retrieved using a previously developed color-ratio based approach. In the second step, corrections for molecular scattering effects are applied to both the observed ad the calculated cloud reflectance terms, and the spectral AAOD is then derived by an inversion of the BL approximation. The proposed technique will be discussed in detail and application results making use of OMI multi-spectral measurements in the UV-Vis. will be presented.

Torres, Omar; Bhartia, Pawan K.; Jethva, H.; Ahn, Chang-Woo

2012-01-01

362

Spectroradiometric considerations for advanced land observing systems  

NASA Technical Reports Server (NTRS)

Research aimed at improving the inflight absolute radiometric calibration of advanced land observing systems was initiated. Emphasis was on the satellite sensor calibration program at White Sands. Topics addressed include: absolute radiometric calibration of advanced remote sensing; atmospheric effects on reflected radiation; inflight radiometric calibration; field radiometric methods for reflectance and atmospheric measurement; and calibration of field relectance radiometers.

Slater, P. N.

1986-01-01

363

Validating Dust Storm Model Using Satellite Aerosol Retrievals and Ground-based Observations  

NASA Astrophysics Data System (ADS)

Dust storm is a meteorological phenomenon with high dust concentration and strong striking force affecting transportation and causing disease. Considering the negative impacts of dust storm, the accuracy of dust storm forecasting is critical for, especially, responding to the emergencies. However, it is challenge to validating the forecasting limited by availability of observation data. The complexity is partially caused by the inconsistency in spatial and temporal resolutions between model simulation and field observation. In addition, the accuracy and reliability of observation data are not guaranteed. Therefore, in order to complement observation data in terms of temporal resolution and enhance the accuracy of observation data, validation methods should be based on data assimilation between satellite and ground-based observations. The dust storm simulation and forecasting model, NMM-dust, coupling Dust Regional Atmospheric Model (DREAM) and Non-hydrostatic Mesoscale Model (NMM) meteorological module, produces higher resolution results for weather forecasting and enabling executability in parallel mode on distributed systems. So far, NMM-dust has been validated in the southwestern US only by comparison with measurement from AIRNOW data and with barely acceptable results. Observation data used for validation includes MODIS and SeaWiFS Deep Blue aerosol products, and ground-based observations from EPA-AQS. Results from comparisons between satellite data and model output show similar dust distribution patterns. Besides, the temporal resolution of satellite data is improved by using both MODIS and SeaWiFS. Quantitative analysis including time-series analysis and diagnose analysis are also examined to investigate the stability and consistency of the model.

YU, M.; Benedict, K. K.; Huang, Q.; Gui, Z.; XIA, J.; Chen, S.

2013-12-01

364

Ameliorating uncertainties in satellite-derived rainfall using GRACE observations over the Congo Basin  

NASA Astrophysics Data System (ADS)

The Congo River has the second largest drainage area in the world, making it very important for the water resources of Africa. Nevertheless, the sparsity of measurements has made the study and modeling of water resources over the basin very difficult and reliant on satellite remote sensing. The Hillslopes River Routing (HRR) model was used to simulate hydrological states and fluxes over the Congo River basin, driven by a TRMM rainfall data product. However, errors in the satellite-derived rainfall, which vary both spatially and temporally, propagate through the model and result in errors in the simulated streamflow and water storage. The GRACE satellite provides measurements of variations of the Earth's gravity field, which can be translated to variations of water storage over large-scale basins. We evaluate a data assimilation system that ingests GRACE water storage variation observations into the HRR model to potentially correct errors in the TRMM precipitation. The data assimilation algorithm, an Ensemble Kalman Filter (EnKF), is able to improve HRR water storage and streamflow predictions when compared with the actual GRACE observations as well as gauge and ENVIsat measurements over select sites, by updating the model rainfall inputs. Additionally, we examine the sensitivity of the rainfall estimates with spatial and temporal scales, i.e. the information content of GRACE observations with respect to estimating TRMM errors. Finally, a Bayesian framework is explored in order to identify the error components that correspond to the HRR parameterization and TRMM inputs.

Andreadis, Konstantinos; Beighley, Edward; Lee, Hyongki; He, Yiping; Alsdorf, Doug; Shum, C. K.

2010-05-01

365

Regional soil moisture retrievals and simulations from assimilation of satellite microwave brightness temperature observations  

Microsoft Academic Search

Low-frequency microwave satellite observations are sensitive to land surface soil moisture (SM). Using satellite microwave\\u000a brightness temperature observations to improve SM simulations of numerical weather, climate and hydrological predictions is\\u000a one of the most active research areas of the geoscience community. In this paper, Yan and Jins’ (J Radio Sci 19(4):386–392,\\u000a 2004) theory on the relationship between satellite microwave remote

Xiaokang ShiJun; Jun Wen; Lei Wang; Tangtang Zhang; Hui Tian; Xin Wang; Rong Liu; Jinghui Zhang

2010-01-01

366

Improving the Transition of Earth Satellite Observations from Research to Operations  

NASA Technical Reports Server (NTRS)

There are significant gaps between the observations, models, and decision support tools that make use of new data. These challenges include: 1) Decreasing the time to incorporate new satellite data into operational forecast assimilation systems, 2) Blending in-situ and satellite observing systems to produce the most accurate and comprehensive data products and assessments, 3) Accelerating the transition from research to applications through national test beds, field campaigns, and pilot demonstrations, and 4) Developing the partnerships and organizational structures to effectively transition new technology into operations. At the Short-term Prediction Research and Transition (SPORT) Center in Huntsville, Alabama, a NASA-NOAA-University collaboration has been developed to accelerate the infusion of NASA Earth science observations, data assimilation and modeling research into NWS forecast operations and decision-making. The SPoRT Center research focus is to improve forecasts through new observation capability and the regional prediction objectives of the US Weather Research Program dealing with 0-1 day forecast issues such as convective initiation and 24-hr quantitative precipitation forecasting. The near real-time availability of high-resolution experimental products of the atmosphere, land, and ocean from the Moderate Resolution Imaging Spectroradiometer (MODIS), the Advanced Infrared Spectroradiometer (AIRS), and lightning mapping systems provide an opportunity for science and algorithm risk reduction, and for application assessment prior to planned observations from the next generation of operational low Earth orbiting and geostationary Earth orbiting satellites. This paper describes the process for the transition of experimental products into forecast operations, current products undergoing assessment by forecasters, and plans for the future. The SPoRT Web page is at (http://www.ghcc.msfc.nasa.gov/sport).

Goodman, Steven J.; Lapenta, William M.; Jedlovec, Gary J.

2004-01-01

367

Engineering calculations for communications satellite systems planning  

NASA Astrophysics Data System (ADS)

The final phase of a satellite synthesis project is described. Several methods for generating satellite positionings with improved aggregate carrier to interference characteristics were studied. Two general methods for modifying required separation values are presented. Also, two methods for improving aggregate carrier to interference (C/I) performance of given satellite synthesis solutions are presented. A perturbation of the World Administrative Radio Conference (WARC) synthesis is presented.

Walton, E.; Aebker, E.; Mata, F.; Reilly, C.

1991-05-01

368

Engineering calculations for communications satellite systems planning  

NASA Technical Reports Server (NTRS)

The final phase of a satellite synthesis project is described. Several methods for generating satellite positionings with improved aggregate carrier to interference characteristics were studied. Two general methods for modifying required separation values are presented. Also, two methods for improving aggregate carrier to interference (C/I) performance of given satellite synthesis solutions are presented. A perturbation of the World Administrative Radio Conference (WARC) synthesis is presented.

Walton, E.; Aebker, E.; Mata, F.; Reilly, C.

1991-01-01

369

Observing the Solar System  

NASA Astrophysics Data System (ADS)

1. Earth and sky; 2. Moon and planet observer's hardware; 3. The Solar System framed; 4. Stacking up the Solar System; 5. Our Moon; 6. Mercury and Venus; 7. Mars; 8. Jupiter; 9. Saturn, Uranus and Neptune; 10. Small worlds; 11. Comets; 12. Our daytime star; Appendices; Index.

North, Gerald

2012-10-01

370

Texstar: The all-Texas educational satellite system  

NASA Technical Reports Server (NTRS)

Longhorn Satellite Company (LSC) has designed Texstar, and educational satellite communications system which will be considered as a means of equalizing the distribution of educational resources throughout the state of Texas. Texstar will be capable of broadcasting live lectures and documentaries in addition to transmitting data from a centralized receiving-transmitting station. Included in the design of Texstar is the system and subsystem design for the satellite and the design of the ground stations. The launch vehicle used will be the Texas-built Conestoga 421-48. The Texstar system incorporates three small satellites in slightly inclined geosynchronous orbits. Due to the configuration and spacing of these satellites, the system will be accessed as if it were one large, geostationary satellite. Texstar is shown to be a viable option to the educational crisis in the state of Texas.

1990-01-01

371

Satellite Observations of NO2 Trend over Romania  

PubMed Central

Satellite-based measurements of atmospheric trace gases loading give a realistic image of atmospheric pollution at global, regional, and urban level. The aim of this paper is to investigate the trend of atmospheric NO2 content over Romania for the period 1996–2010 for several regions which are generally characterized by different pollutant loadings, resulting from GOME-1, SCIAMACHY, OMI, and GOME-2 instruments. Satellite results are then compared with ground-based in situ measurements made in industrial and relatively clean areas of one major city in Romania. This twofold approach will help in estimating whether the trend of NO2 obtained by means of data satellite retrievals can be connected with the evolution of national industry and transportation. PMID:24453819

Voiculescu, Mirela; Georgescu, Lucian

2013-01-01

372

218 IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, VOL. 22, NO. 2, FEBRUARY 2004 Cache Satellite Distribution Systems: Modeling,  

E-print Network

218 IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS, VOL. 22, NO. 2, FEBRUARY 2004 Cache Satellite observed by Web clients. Cache satellite distribution systems (CSDSs) have emerged as a technology. The central station selects a collection of Web documents, which are "pushed" via a satellite broadcast

Levy, Hanoch

373

The use of stereoscopic satellite observation in the determination of the emissivity of cirrus  

NASA Astrophysics Data System (ADS)

The feasibility of determining cirrus ``emissivity'' from combined stereoscopic and infrared satellite observations in conjunction with radiosounding data is investigated for a particular case study. Simultaneous visible images obtained during SESAME-1979 from two geosynchronous GOES meteorological satellites were processed on the NASA/Goddard interactive system (AOIPS) and were used to determine the stereo cloud top height ZC as described by Hasler [1]. Iso-contours of radiances were outlined on the corresponding infrared image. Total brightness temperature TB and ground surface brightness temperature TS were inferred from the radiances. The special SESAME network of radiosoundings was used to determine the cloud top temperature TCLD at the level defined by ZC. The ``effective cirrus emissivity'' NE where N is the fractional cirrus cloudiness and E is the emissivity in a GOES infrared picture element of about 10 km × 10 km is then computed from TB, TS and TCLD.

Szejwach, G.; Sletten, T. N.; Hasler, A. F.

374

Coincident multispectral satellite observations of marine stratocumulus clouds near the Azores Islands  

SciTech Connect

Marine stratocumulus clouds (MSC) have been the subject of much climate research because of their effect on the earth`s radiative energy budget. The radiative properties of MSC are determined primarily by their water content and spatial distribution. Satellite data provide an excellent opportunity to characterize these parameters. In this study, the authors use coincident observations from two sensors on the same Defense Meteorological Satellite Program (DMSP) platform: visible and infrared data are provided by the Operational Linescan System (OLS), and passive microwave data are provided by the Special Sensor Microwave Imager (SSMI). The OLS data facilitate the interpretation of the atmospheric parameters retrieved from the SSMI by putting them in a familiar context and allowing a subpixel analysis of the relatively large SSMI footprint. The objective is to explore the relationships between the SSMI-derived and the OLS-derived cloud parameters.

Miletta, J.; Katsaros, K.B. [Univ. of Washington, Seattle, WA (United States). Dept. of Atmospheric Sciences

1994-12-31

375

Orbits design for LEO space based solar power satellite system  

NASA Astrophysics Data System (ADS)

Space Based Solar Power satellites use solar arrays to generate clean, green, and renewable electricity in space and transmit it to earth via microwave, radiowave or laser beams to corresponding receivers (ground stations). These traditionally are large structures orbiting around earth at the geo-synchronous altitude. This thesis introduces a new architecture for a Space Based Solar Power satellite constellation. The proposed concept reduces the high cost involved in the construction of the space satellite and in the multiple launches to the geo-synchronous altitude. The proposed concept is a constellation of Low Earth Orbit satellites that are smaller in size than the conventional system. 7For this application a Repeated Sun-Synchronous Track Circular Orbit is considered (RSSTO). In these orbits, the spacecraft re-visits the same locations on earth periodically every given desired number of days with the line of nodes of the spacecraft's orbit fixed relative to the Sun. A wide range of solutions are studied, and, in this thesis, a two-orbit constellation design is chosen and simulated. The number of satellites is chosen based on the electric power demands in a given set of global cities. The orbits of the satellites are designed such that their ground tracks visit a maximum number of ground stations during the revisit period. In the simulation, the locations of the ground stations are chosen close to big cities, in USA and worldwide, so that the space power constellation beams down power directly to locations of high electric power demands. The j2 perturbations are included in the mathematical model used in orbit design. The Coverage time of each spacecraft over a ground site and the gap time between two consecutive spacecrafts visiting a ground site are simulated in order to evaluate the coverage continuity of the proposed solar power constellation. It has been observed from simulations that there always periods in which s spacecraft does not communicate with any ground station. For this reason, it is suggested that each satellite in the constellation be equipped with power storage components so that it can store power for later transmission. This thesis presents a method for designing the solar power constellation orbits such that the number of ground stations visited during the given revisit period is maximized. This leads to maximizing the power transmission to ground stations.

Addanki, Neelima Krishna Murthy

2011-12-01

376

SATELLITES AROUND MASSIVE GALAXIES SINCE z {approx} 2: CONFRONTING THE MILLENNIUM SIMULATION WITH OBSERVATIONS  

SciTech Connect

Minor merging has been postulated as the most likely evolutionary path to produce the increase in size and mass observed in the massive galaxies since z {approx} 2. In this Letter, we directly test this hypothesis, comparing the population of satellites around massive galaxies in cosmological simulations versus the observations. We use state-of-the-art, publically available, Millennium I and II simulations, and the associated semi-analytical galaxy catalogs to explore the time evolution of the fraction of massive galaxies that have satellites, the number of satellites per galaxy, the projected distance at which the satellites locate from the host galaxy, and the mass ratio between the host galaxies and their satellites. The three virtual galaxy catalogs considered here overproduce the fraction of galaxies with satellites by a factor ranging between 1.5 and 6 depending on the epoch, whereas the mean projected distance and ratio of the satellite mass over host mass are in closer agreement with data. The larger pull of satellites in the semi-analytical samples could suggest that the size evolution found in previous hydrodynamical simulations is an artifact due to the larger number of infalling satellites compared to the real universe. These results advise us to revise the physical ingredients implemented in the semi-analytical models in order to reconcile the observed and computed fraction of galaxies with satellites, and eventually, it would leave some room for other mechanisms explaining the galaxy size growth not related to the minor merging.

Quilis, Vicent [Departament d'Astronomia i Astrofisica, Universitat de Valencia, 46100-Burjassot, Valencia (Spain); Trujillo, Ignacio, E-mail: vicent.quilis@uv.es [Instituto de Astrofisica de Canarias, c/ Via Lactea s/n, E38205-La Laguna, Tenerife (Spain)

2012-06-20

377

IRSUTE: a multispectral IR observation instrument on a small satellite  

NASA Astrophysics Data System (ADS)

Satellite remote sensing measurements in the thermal IR spectrum have existed since the beginning of the space era with the first Tiros satellites in the sixties. The low spatial resolution data provided up to now have been mainly used for mesoscale applications in meteorology and oceanography. To study and understand on a local scale those natural phenomena which can be characterized by their radiative temperatures, the users need high spatial resolution data in multi-spectral channels with a good radiometric sensitivity. Thanks to recent progress in IR detector technology, these specifications will soon be satisfied. The IRSUTE (infra red satellite unit for terrestrial environment) instrument is designed to provide high spatial (50 m), multi-spectral (4 channels in the IR), high repetivity data with a good radiometric sensitivity. Moreover, the IRSUTE payload has to be compatible with the limited resources (mass, power, volume, ...) provided by a small satellite. The design of the instrument is based on the push-broom technique which uses IR-CCD linear array detectors positioned in the focal plane of a collecting telescope. The first results of a pre-feasibility study on the inboard instrument are presented.

Durpaire, Jean-Pierre; Phulpin, T.; Hollier, Pierre A.

1995-09-01

378

SatCam: A mobile application for coordinated ground/satellite observation of clouds and validation of satellite-derived cloud mask products.  

NASA Astrophysics Data System (ADS)

SatCam is an application for iOS devices that allows users to collect observations of local cloud and surface conditions in coordination with an overpass of the Terra, Aqua, or NPP satellites. SatCam allows users to acquire images of sky conditions and ground conditions at their location anywhere in the world using the built-in iPhone or iPod Touch camera at the same time that the satellite is passing overhead and viewing their location. Immediately after the sky and ground observations are acquired, the application asks the user to rate the level of cloudiness in the sky (Completely Clear, Mostly Clear, Partly Cloudy, Overcast). For the ground observation, the user selects their assessment of the surface conditions (Urban, Green Vegetation, Brown Vegetation, Desert, Snow, Water). The sky condition and surface condition selections are stored along with the date, time, and geographic location for the images, and the images are uploaded to a central server. When the MODIS (Terra and Aqua) or VIIRS (NPP) imagery acquired over the user location becomes available, a MODIS or VIIRS true color image centered at the user's location is delivered back to the SatCam application on the user's iOS device. SSEC also proposes to develop a community driven SatCam website where users can share their observations and assessments of satellite cloud products in a collaborative environment. SSEC is developing a server side data analysis system to ingest the SatCam user observations, apply quality control, analyze the sky images for cloud cover, and collocate the observations with MODIS and VIIRS satellite products (e.g., cloud mask). For each observation that is collocated with a satellite observation, the server will determine whether the user scored a "hit", meaning their sky observation and sky assessment matched the automated cloud mask obtained from the satellite observation. The hit rate will be an objective assessment of the accuracy of the user's sky observations. Users with high hit rates will be identified automatically and their observations will be used globally to evaluate the performance of the MODIS cloud mask algorithm for Terra and Aqua and the VIIRS cloud mask algorithm for NPP. The user's assessment of the ground conditions will also be used to evaluate the cloud mask accuracy in selecting the correct surface type at the user's location, which is an important element in the decision path used internally by the cloud mask algorithm. This presentation will describe the SatCam application, how it is used, and show examples of SatCam observations.

Gumley, L.; Parker, D.; Flynn, B.; Holz, R.; Marais, W.

2011-12-01

379

Satellite Power System (SPS) financial/management scenarios  

NASA Technical Reports Server (NTRS)

The possible benefits of a Satellite Power System (SPS) program, both domestically and internationally, justify detailed and imaginative investigation of the issues involved in financing and managing such a large-scale program. In this study, ten possible methods of financing a SPS program are identified ranging from pure government agency to private corporations. The following were analyzed and evaluated: (1) capital requirements for SPS; (2) ownership and control; (3) management principles; (4) organizational forms for SPS; (5) criteria for evaluation; (6) detailed description and preliminary evaluation of alternatives; (7) phased approaches; and (8) comparative evaluation. Key issues and observations and recommendations for further study are also presented.

Vajk, J. P.

1978-01-01

380

Radiative Transfer, Satellite Retrieval Systems and 32 Years  

E-print Network

Radiative Transfer, Satellite Retrieval Systems and 32 Years of Federal Service or What Have I Been vapor absorption band. #12;Satellite Processing and Display System · Worked on ingesting GOES Mode AA;#12;#12;How did we program back then? · Punch cards and tape #12;#12;Cloud Tracking · Cross

Kuligowski, Bob

381

Analysis of submarine cable and communication satellite systems reliabilities  

Microsoft Academic Search

The performance of AT&T's overseas message telephone circuits for the years 1970-1975 was the basis for ana analysis of the reliability of submarine cables and communication satellite systems. Data presented in 24 tables is devided into three categories: (1) over cable and satellite system outage statistics for each of the six years and the six year average, (2) detailed cable

G. S. Li

1977-01-01

382

On-Demand Routing in LEO Satellite Systems Stylianos Karapantazis  

E-print Network

On-Demand Routing in LEO Satellite Systems Stylianos Karapantazis Aristotle University@auth.gr Abstract--In this paper, a location-assisted on-demand routing (LAOR) protocol for low earth orbit (LEO) satellite systems is proposed and evaluated. This protocol can be viewed as a variant of the well-known ad

Papapetrou, Evaggelos

383

Computer-Aided Communication Satellite System Analysis and Optimization.  

ERIC Educational Resources Information Center

Various published computer programs for fixed/broadcast communication satellite system synthesis and optimization are discussed. The rationale for selecting General Dynamics/Convair's Satellite Telecommunication Analysis and Modeling Program (STAMP) in modified form to aid in the system costing and sensitivity analysis work in the Program on…

Stagl, Thomas W.; And Others

384

1993 Earth Observing System reference handbook  

NASA Technical Reports Server (NTRS)

Mission to Planet Earth (MTPE) is a NASA-sponsored concept that uses space- and ground-based measurement systems to provide the scientific basis for understanding global change. The space-based components of MTPE will provide a constellation of satellites to monitor the Earth from space. Sustained observations will allow researchers to monitor climate variables overtime to determine trends; however, space-based monitoring alone is not sufficient. A comprehensive data and information system, a community of scientists performing research with the data acquired, and extensive ground campaigns are all important components. Brief descriptions of the various elements that comprise the overall mission are provided. The Earth Observing System (EOS) - a series of polar-orbiting and low-inclination satellites for long-term global observations of the land surface, biosphere, solid Earth, atmosphere, and oceans - is the centerpiece of MTPE. The elements comprising the EOS mission are described in detail.

Asrar, Ghassem (editor); Dokken, David Jon (editor)

1993-01-01

385

System requirements for laser power beaming to geosynchronous satellites  

SciTech Connect

Geosynchronous satellites use solar arrays as their primary source of electrical power. During earth eclipse, which occurs 90 times each year, the satellites are powered by batteries, but the heavy charge-discharge cycle decreases their life expectancy. By beaming laser power to satellites during the eclipses, satellite life expectancy can be significantly increased. In this paper, the authors investigate the basic system parameters and trade-offs of using reactor pumped laser technology to beam power from the Nevada Test Site. A first order argument is used to develop a consistent set of requirements for such a system.

Neal, R.D. [Martin Marietta, Denver, CO (United States); McKechnie, T.S. [POD Associates, Albuquerque, NM (United States); Neal, D.R. [Sandia National Labs., Albuquerque, NM (United States)

1994-12-31

386

System requirements for laser power beaming to geosynchronous satellites  

SciTech Connect

Geosynchronous satellites use solar arrays as their primary source of electrical power. During earth eclipse, which occurs 90 times each year, the satellites are powered by batteries, but the heavy charge-discharge cycle decreases their life expectancy. By beaming laser power to satellites during the eclipses, satellite life expectancy can be significantly increased. In this paper, the authors investigate the basic system parameters and trade-offs of using reactor pumped laser technology to beam power from the Nevada Test Site. A first order argument is used to develop a consistent set of requirements for such a system.

Neal, R.D. [Martin Marietta, Denver, CO (United States); McKechnie, T.S. [POD Associates, Albuquerque, NM (United States); Neal, D.R. [Sandia National Labs., Albuquerque, NM (United States)

1994-03-01

387

Reusable Reentry Satellite (RRS) system design study  

NASA Technical Reports Server (NTRS)

The Reusable Reentry Satellite (RRS) is intended to provide investigators in several biological disciplines with a relatively inexpensive method to access space for up to 60 days with eventual recovery on Earth. The RRS will permit totally intact, relatively soft, recovery of the vehicle, system refurbishment, and reflight with new and varied payloads. The RRS is to be capable of three reflights per year over a 10-year program lifetime. The RRS vehicle will have a large and readily accessible volume near the vehicle center of gravity for the Payload Module (PM) containing the experiment hardware. The vehicle is configured to permit the experimenter late access to the PM prior to launch and rapid access following recovery. The RRS will operate in one of two modes: (1) as a free-flying spacecraft in orbit, and will be allowed to drift in attitude to provide an acceleration environment of less than 10(exp -5) g. the acceleration environment during orbital trim maneuvers will be less than 10(exp -3) g; and (2) as an artificial gravity system which spins at controlled rates to provide an artificial gravity of up to 1.5 Earth g. The RRS system will be designed to be rugged, easily maintained, and economically refurbishable for the next flight. Some systems may be designed to be replaced rather than refurbished, if cost effective and capable of meeting the specified turnaround time. The minimum time between recovery and reflight will be approximately 60 days. The PMs will be designed to be relatively autonomous, with experiments that require few commands and limited telemetry. Mass data storage will be accommodated in the PM. The hardware development and implementation phase is currently expected to start in 1991 with a first launch in late 1993.

1991-01-01

388

Reusable Reentry Satellite (RRS) system design study  

NASA Astrophysics Data System (ADS)

The Reusable Reentry Satellite (RRS) is intended to provide investigators in several biological disciplines with a relatively inexpensive method to access space for up to 60 days with eventual recovery on Earth. The RRS will permit totally intact, relatively soft, recovery of the vehicle, system refurbishment, and reflight with new and varied payloads. The RRS is to be capable of three reflights per year over a 10-year program lifetime. The RRS vehicle will have a large and readily accessible volume near the vehicle center of gravity for the Payload Module (PM) containing the experiment hardware. The vehicle is configured to permit the experimenter late access to the PM prior to launch and rapid access following recovery. The RRS will operate in one of two modes: (1) as a free-flying spacecraft in orbit, and will be allowed to drift in attitude to provide an acceleration environment of less than 10(exp -5) g. the acceleration environment during orbital trim maneuvers will be less than 10(exp -3) g; and (2) as an artificial gravity system which spins at controlled rates to provide an artificial gravity of up to 1.5 Earth g. The RRS system will be designed to be rugged, easily maintained, and economically refurbishable for the next flight. Some systems may be designed to be replaced rather than refurbished, if cost effective and capable of meeting the specified turnaround time. The minimum time between recovery and reflight will be approximately 60 days. The PMs will be designed to be relatively autonomous, with experiments that require few commands and limited telemetry. Mass data storage will be accommodated in the PM. The hardware development and implementation phase is currently expected to start in 1991 with a first launch in late 1993.

1991-02-01

389

Determination of Thundercloud Ice Characteristics from Satellite Observations of Lightning  

Microsoft Academic Search

Satellite-borne NASA\\/MSFC devices for the detection of global lightning (the OTD and the LIS) offer the opportunity to explore relationships between lightning frequency f and other thundercloud parameters: more specifically, to determine from measurements of f precipitating and non-precipitating ice fluxes. Computations predict that f is proportional to the product of the downward flux fg of graupel through the body

J. Latham; A. Blyth; H. Christian; A. Gadian

2002-01-01

390

Committee on Earth Observation Satellites (CEOS) perspectives about the GEO Supersite initiative  

NASA Astrophysics Data System (ADS)

This presentation is outlining the effort of the Committee on Earth Observation Satellites (CEOS) using its global collaboration structure to support implementing the GEO priority action DI-01 Informing Risk Management and Disaster Reduction addressing the component: C2 Geohazards Monitoring, Alert, and Risk Assessment. A CEOS Supersites Coordination Team (SCT) has been established in order to make best use of the CEOS global satellite resources. For this, the CEOS SCT has taken a holistic view on the science data needs and availability of resources, considering the constraints and exploitation potentials of synergies. It is interfacing with the Supersites Science Advisory Group and the Principle Investigators to analyze how the satellite data associated with seismic and Global Navigation Satellite System (GNSS) data can support national authorities and policy makers in risk assessment and the development of mitigation strategies. CEOS SCT aims to support the establishment of a fully integrated approach to geohazards monitoring, based on collaboration among existing networks and international initiatives, using new instrumentation such as in-situ sensors, and aggregating space (radar, optical imagery) and ground-based (subsurface) observations. The three Supersites projects which are funded under the EC FP7 action, namely (i) FUTUREVOLC: A European volcanological supersite in Iceland: a monitoring system and network for the future Geohazards Monitoring, Alert, and Risk Assessment, (ii) MARsite: New Directions in Seismic Hazard assessment through Focused Earth Observation in the Marmara Supersite, (iii) MED-SUV: MEDiterranean Volcanoes and related seismic risks, have been examined as a vehicle to fulfill these ambitious objectives. FUTUREVOLC has already been granted CEOS support. This presentation will outline CEOS agreed process and criteria applied by the Supersites Coordination Team (SCT), for selecting these Supersites in the context of the GSNL initiative, as well provide information about the satellite data provided by CEOS for the different Supersites. ASI - COSMO-Skymed CNES - SPOT-5, Pleiades CSA - Radarsat-2 DLR - TerraSAR-X, TanDEM-X ESA - ERS-1/2, Envisat, Sentinel (on behalf of EC - Copernicus) JAXA - ALOS-2, ALOS-1, J-ERS NASA - ASTER

Lengert, Wolfgang; Zoffoli, Simona; Giguere, Christine; Hoffmann, Joern; Lindsay, Francis; Seguin, Guy

2014-05-01

391

Multi-stakeholder Interactive Simulation for Federated Satellite Systems  

E-print Network

Federated satellite systems (FSS) are a new class of space-based systems which emphasize a distributed architecture. New information exchanging functions among FSS members enable data transportation, storage, and processing ...

Grogan, Paul Thomas

392

Earth Observatory Satellite system definition study. Report 5: System design and specifications. Volume 2: EOS-A system specification  

NASA Technical Reports Server (NTRS)

The objectives of the Earth Observatory Satellite (EOS) program are defined. The system specifications for the satellite payload are examined. The broad objectives of the EOS-A program are as follows: (1) to develop space-borne sensors for the measurement of land resources, (2) to evolve spacecraft systems and subsystems which will permit earth observation with greater accuracy, coverage, spatial resolution, and continuity than existing systems, (3) to develop improved information processing, extraction, display, and distribution systems, and (4) to use space transportation systems for resupply and retrieval of the EOS.

1974-01-01

393

Synchronization of system-of-systems interfaces in military satellite communications  

E-print Network

Military systems continue to become more complex and nearly all are now part of one or more system of systems (SoS). Military satellite communications programs have expanded over the last decade from three distinct satellite ...

Davis, Mark J. (Mark Jeffrey)

2008-01-01

394

Spaceborne observations of a changing Earth - Contribution from ESÁ s operating and approved satellite missions.  

NASA Astrophysics Data System (ADS)

The overall vision for ESÁs Earth Observation activities is to play a central role in developing the global capability to understand planet Earth, predict changes, and mitigate negative effects of global change on its populations. Since Earth observation from space first became possible more than forty years ago, it has become central to monitoring and understanding how the dynamics of the Earth System work. The greatest progress has been in meteorology, where space-based observations have become indispensable, but it is now also progressively penetrating many of the fields making up Earth sciences. Exploiting Earth observation from space presents major multidisciplinary challenges to the researches working in the Earth sciences, to the technologists who build the state-of-the-art sensors, and to the scientists interpreting measurements made of processes occurring on or within the Earth's surface and in its atmosphere. The scientific community has shown considerable imagination in rising to these challenges, and in exploiting the latest technological developments to measure from space the complex processes and interactions that occur in the Earth System. In parallel, there has been significant progress in developing computer models that represent the many processes that make up the Earth System, and the interactions and feedback between them. Success in developing this holistic view is inextricably linked to the data provided by Earth Observation systems. Satellites provide the fundamental, consistent, regular and global measurements needed to drive, parameterise, test and improve those Earth System models. These developments, together with changes in society's awareness of the need for information on a changing world, have repetitively supported the decisions on how ESA can best focus its resources, and those of the European community that it serves, in order to address critical issues in Earth System science. Moreover, it is a fact that many operational, managerial and regulatory activities (i.e. weather forecasting, deforestation, flooding, etc.) essential to the safe exploitation of global resources, conservation of sustainable ecosystems, and the compliance with numerous international treaties and conventions, depend absolutely on continuity of satellite missions to maximise socio-economic and environmental benefits. This presentation will highlight some of the multidisciplinary Earth science achievements and operational applications using ESA satellite missions. It will also address some of the key scientific challenges and need for operational monitoring services in the years to come. It capitalizes on the knowledge and awareness outlined in "The Changing Earth - New scientific challenges for ESÁs Living Planet Programme" issued in 2006 together with updated views and approved plans expressed during ESÁs Earth Sciences Advisory Committee (ESAC) meetings and agreed at the recent User Consultation meeting in January 2009.

Johannessen, J. A.

2009-04-01

395

Synergy of Satellite-Surface Observations for Studying the Properties of Absorbing Aerosols in Asia  

NASA Technical Reports Server (NTRS)

Through interaction with clouds and alteration of the Earth's radiation budget, atmospheric aerosols significantly influence our weather and climate. Monsoon rainfalls, for example, sustain the livelihood of more than half of the world's population. Thus, understanding the mechanism that drives the water cycle and freshwater distribution is high-lighted as one of the major near-term goals in NASA's Earth Science Enterprise Strategy. Every cloud droplet/ice-crystal that serves as an essential element in portraying water cycle and distributing freshwater contains atmospheric aerosols at its core. In addition, the spatial and temporal variability of atmospheric aerosol properties is complex due to their dynamic nature. In fact, the predictability of the tropical climate system is much reduced during the boreal spring, which is associated with the peak season of biomass burning activities and regional/long-range transport of dust aerosols. Therefore, to accurately assess the impact of absorbing aerosols on regional-to-global climate requires not only modeling efforts but also continuous observations from satellites, aircraft, networks of ground-based instruments and dedicated field experiments. Since 1997 NASA has been successfully launching a series of satellites the Earth Observing System - to intensively study, and gain a better understanding of, the Earth as an integrated system. Through participation in many satellite remote-sensing/retrieval and validation projects over the years, we have gradually developed and refined the SMART (Surface-sensing Measurements for Atmospheric Radiative Transfer) and COMMIT (Chemical, Optical & Microphysical Measurements of In-situ Troposphere) mobile observatories, a suite of surface remote sensing and in-situ instruments that proved to be vital in providing high temporal measurements, which complement the satellite observations. In this talk, we will present SMART-COMMIT which has played key roles, serving as network or supersite, in major international research projects such as the Joint Aerosol Monsoon Experiment (JAM EX), a core element of the Asian Monsoon Years (AMY, 2008-2012). SMART-COMMIT deployments during 2008 AMY/JAMEX were conducted in northwestern China to characterize the properties of dust-laden aerosols and in the vicinity of Beijing for mega-city aerosols. In 2009, SMART-COMMIT also participated in the JAMEX/RAJO-MEGHA (Radiation, Aerosol Joint Observations-Monsoon Experiment in the Gangetic-Himalayan Area; Sanskrit for Dust-Cloud) to study the aerosol properties, solar absorption and the associated atmospheric warming, and the climatic impact of elevated aerosols during the pre-monsoon season in South Asia. We will show results from these field experiments, as well as discuss a new initiative of 7-SEAS (7 South East Asian Studies) to study the interaction of anthropogenic aerosols with regional meteorology, particularly with clouds.

Tsay, Si-Chee

2010-01-01

396

CEOS WGISS Integrated Catalog, A Catalog for Earth Observation Satellite Data  

NASA Astrophysics Data System (ADS)

The Committee on Earth Observation Satellites (CEOS) was formed in 1984 to coordinate the world's civil space-borne observations of the Earth. More recently, CEOS and its member agencies have committed to provide the implementation of the space-based component of the Group on Earth Observation (GEO) Global Earth Observation System of Systems (GEOSS) Common Infrastructure (GCI). In the case of CEOS, there are a number of challenges in directly connecting the components and services of its member agencies to the GCI. In many cases, the existing catalog systems of the member agencies do not support the OGC Catalog Service for the Web (CSW) that has been selected as the standard for the GCI. Another challenge is related to the fact that collections of satellite data products are extremely large and constantly growing with millions of individual products. Harvesting the associated metadata into the clearinghouse of the GCI is not a practical alternative. In addition, the collection/granule hierarchy and unique spatial/temporal characteristics of satellite data and the user registration and asynchronous access requirements of the agency systems pose additional challenges. The CEOS approach has been to design and implement a CEOS WGISS Integrated Catalog (CWIC) that will serve as a community catalog of the products and services that are offered through its member's systems. CWIC will be based on a distributed search architecture and serve as a gateway between the GEO portal or community portals and clients and the CEOS agency systems. CWIC will receive standard search queries from these portals or clients all using the GEO supported catalog standard, the OGC CSW 2.0.2 and the WGISS Search Criteria for granule search and translate them into the native protocols of the underlying catalogs. Likewise, the result sets from the CEOS agency catalogs will be converted to the form that will be compatible with the portals and clients. The CWIC data provider partners include NOAA, NASA, USGS, INPE (Brazil), and two Chinese data centers coordinated by the Chinese Academy of Science have joined the engineering team and their systems are accessible via CWIC. In addition, multiple other CEOS agencies are or plan to be members of the teams developing community portals and clients that will access CWIC. Recently, NASA initiated development of a prototype client to access CWIC. The ultimate goal of the CEOS WGISS effort is to make the satellite data and services of its member agencies more accessible and useful to the broad set of GEO research programs and applications and this is most effectively approached by harmonization within the satellite community. This kind of community-based development with the harmonization occurring first within the community and then being offered to the broader GEO systems fits the original GEO vision of becoming "a system of systems", clearly representing a contribution towards achieving full interoperability in a standards-based manner.

Enloe, Y.; Yapur, M.

2011-12-01

397

A practical system for regional mobile satellite services  

NASA Technical Reports Server (NTRS)

The Regional Mobile Satellite (MSAT) concept proposes a worldwide, interconnected mobile satellite service (MSS) network in which MSAT-type satellites provide the space segment services to separate regions (i.e., one or a few countries). Using this concept, mobile communications users across entire continents can now be served by a handful of regionally controlled satellites in geostationary earth orbit (GEO). All requirements, including hand-held telephone capabilities, can be cost-effectively provided using proven technologies. While other concepts of regional or global mobile communications continue to be explored, the Hughes Regional MSAT system demonstrates the near-term viability of the GEO approach.

Glein, Randall; Leverson, Denis; Olmstead, Dean

1993-01-01

398

Satellite power system (SPS) brightness due to reflected sunlight  

SciTech Connect

The development and operation of a Satellite Power System would place very large structures in orbit around earth for several decades. Sunlight reflected off such structures, particularly specular components from large flat areas, is expected to create ground illumination that will attract observers. In order to assure that this illumination does not exceed the irradiance tolerances of the eye, reflections from these satellites must be carefully controlled by vehicle orientation and surface specifications. The solar power satellite (SPS) at geosynchronous earth orbit (GEO) has 55 km/sup 2/ of glass covered solar cells that are oriented normal to the sun, as well as a 1 km/sup 2/ microwave antenna. Transportation of construction materials from low earth orbit (LEO) to GEO requires 23 Orbit Transfer Vehicles (OTVs) that have 1.6 km/sup 2/ solar panels oriented normal to the sun during their 6 month transits. The Staging Base (SB) at LEO, that accommodates OTV fabrication and cargo transfer, consists of 0.5 km arms protruding from a .44 km/sup 2/ open grid aligned with its orbit plane. Diffuse reflections would make the SB/OTVs readily discernible in the daytime and the OTVs and SPSs observable all night (except during eclipse). Sporadic specular glints would appear on the ground from the OTVs and SPSs near the midnight meridian, from the solar panel surfaces of OTVs during LEO fabrication around midday, and from OTVs near LEO at dawn and dusk. The ground level irradiance has been evaluated for several unusually bright configurations using the present system design. Procedures and results are presented and discussed.

None

1980-10-01

399

Astrometric observations of Saturn's satellites from McDonald Observatory, 1972. [using reference stars  

NASA Technical Reports Server (NTRS)

Observations of Saturn's satellites were reduced by means of secondary reference stars obtained by reduction of Palomar Sky Survey (PSS) plates. This involved the use of 39 SAO stars and plate overlap technique to determine the coordinates of 59 fainter stars in the satellite field. Fourteen plate constants were determined for each of the two PSS plates. Comparison of two plate measurement and reduction techniques on the satellite measurements demonstrate the existence of a serious background gradient effect and the utility of microdensitometry to eliminate this error source in positional determinations of close satellites.

Abbot, R. I.; Mulholland, J. D.; Shelus, P. J.

1974-01-01

400

Astrometric observations of Saturn's satellites from McDonald Observatory, 1972  

NASA Technical Reports Server (NTRS)

Observations of Saturn's satellites have been reduced by means of secondary reference stars obtained by reduction of Palomar Sky Survey plates. This involved the use of 29 SAO stars and plate overlap technique to determine the coordinates of 59 fainter stars in the satellite field. Fourteen plate constants were determined for each of the two PSS plates. Comparison of two plate measurement and reduction techniques on the satellite measures appears to demonstrate the existence of a serious background gradient effect and the utility of microdensitometry to eliminate this error source in positional determinations of close satellites.

Abbot, R. I.; Mulholland, J. D.; Shelus, P. J.

1975-01-01

401

Simulation and graphical representation of the orbit and the imaging parameter of Earth observation satellites  

Microsoft Academic Search

Synthetic aperture radar (SAR) satellites are widely used for Earth observation applications as weather conditions and cloudiness do not affect them. However, in order to be usable, data provided by those satellites need to be processed. This processing requires determination of imaging parameters that are closely linked to the spacecraft position and velocity on its orbit. For example, the difference

Jean-François Vandenrijt

2005-01-01

402

Wind resources and wind farm wake effects offshore observed from satellite  

E-print Network

Wind resources and wind farm wake effects offshore observed from satellite Charlotte Bay Hasager to quantify the wake effect at two large offshore wind farms in Denmark. It is found that the wake velocity than for near-neutral conditions. Keywords: satellite, offshore wind resource, wake. 1 Introduction

403

Astrometric observations of Saturn's satellites from McDonald Observatory, 1972  

Microsoft Academic Search

Observations of Saturn's satellites have been reduced by means of secondary reference stars obtained by reduction of Palomar Sky Survey plates. This involved the use of 29 SAO stars and plate overlap technique to determine the coordinates of 59 fainter stars in the satellite field. Fourteen plate constants were determined for each of the two PSS plates. Comparison of two

R. I. Abbot; J. D. Mulholland; P. J. Shelus

1975-01-01

404

Astrometric observations of Saturn's satellites from McDonald Observatory, 1972  

Microsoft Academic Search

Observations of Saturn's satellites were reduced by means of secondary reference stars obtained by reduction of Palomar Sky Survey (PSS) plates. This involved the use of 39 SAO stars and plate overlap technique to determine the coordinates of 59 fainter stars in the satellite field. Fourteen plate constants were determined for each of the two PSS plates. Comparison of two

R. I. Abbot; J. D. Mulholland; P. J. Shelus

1974-01-01

405

Simultaneous observations of discrete and diffuse auroras by the Isis 2 satellite and airborne instruments  

Microsoft Academic Search

All-sky camera and photometric data were obtained by airborne instrumentation as a function of latitude and time during the course of an auroral substorm. During the substorm recovery phase the Isis 2 satellite passed within 60 km of the aircraft zenith. The discrete and diffuse auroral regions were identified from the airborne all-sky camera data. Satellite and photometric observations of

Charles Sterling Deehr; Fumihiko Yasuhara; Syun-Ichi Akasofu

1976-01-01

406

On the possibility of using VLBI phase referencing to observe GNSS satellites  

NASA Astrophysics Data System (ADS)

The phase referencing technique is an observing method that could contribute to improve accuracy in GNSS satellite positioning and to obtain satellite coordinates directly in ICRF. However, the strong power emitted by the satellites compared to the very low emission of natural radio sources (calibrators) could represent a limiting factor. In fact, the satellite signal can be easily detected through near sidelobes when observing, at the same satellite frequency, the natural calibrator in the main beam. With this work we have run some simulations for some European VLBI antennas using the GRASP (General Reflector antenna Analysis Software Package) v.10 software to assess the relative power contribution of satellites in the near sidelobes when observing in L-band a natural calibrator in the main beam. For each examined station, we have evaluated the minimum angular distance between the satellite and the calibrator to avoid near-sidelobes straylight contamination from the satellite emission when the calibrator is tracked. A discussion of the obtained results is presented and possible observational methods are suggested.

Tornatore, V.; Mennella, A.

2013-08-01

407

Formation of multiple-satellite systems from circumplanetary particle disks  

NASA Astrophysics Data System (ADS)

In the solar system, most of the planets have satellite systems around them. In systems with a single satellite such as Earth-Moon system, satellite mass is relatively high compared to the host planet’s mass. On the other hand, giant planets such as Jupiter, Saturn have multiple-satellite systems. Generally, their inner major satellites called regular satellites exist outside their Roche limit with relatively small mass ratio to the host planet. Those inner satellites are on nearly circular prograde orbits with low inclination. Formation of large regular satellites of Jupiter and Saturn has been explained by accretion in a circumplanetary gas disk (Canup & Ward 2009). On the other hand, it has been recently shown that regular satellites of Saturn, Uranus and Neptune can be formed from a circumplanetary particle disks within the Roche limit (Crida & Charnoz 2012). Formation of satellites from those particle disks was first studied in the context of lunar formation (Ida, S., et al., 1997). Initially, particles are distributed within the Roche limit and their accretion is prohibited. Then, the disk spreads with time. As the disk spreads and the disk materials diffuse beyond the Roche limit, the materials start to form gravitationally bound aggregates. In the case of relatively massive disk, a large single satellite is its outcome (Ida, S., et al., 1997). However, if the initial disk is less massive, the viscosity of the disk is low and the time scale of disk diffusion is much longer. These aspects expect to lead to the different outcomes. Crida and Charnoz (2012) developed an analytic model for the formation of multiple satellites from a circumplanetary particle disk, with the assumption that the mass flow through the Roche limit is constant. Their model successfully explains the characteristics of the masses and orbits in the satellite systems of Saturn, Uranus and Neptune. However, the details of the evolution of less massive disk are still unclear. In the present work, we perform N-body simulations in order to see the evolution of less massive circumplanetary particle disks, and show that another satellite is secondly formed from a residual disk after the formation of the first satellite.

Hyodo, Ryuki; Ohtsuki, K.; Takeda, T.

2013-10-01

408

Satellite observations and instrumentation for measuring energetic neutral atoms  

SciTech Connect

Direct measurements of energetic neutral atoms (ENA) and ions have been obtained with the cooled solid state detectors on the low-altitude (220 km) three-axis stabilized S81-1/ stimulated emissions of energetic particles (SEEP) satellite and on the spinning 400 km [times] 5.5 R[sub e] (where R[sub e] is Earth radii) Combined Release and Radiation Effects Satellite (CRRES). During magnetic storms ENA and ion precipitation (E > 10 keV) are evident over the low-altitude equatorial region based on data from the SEEP (ONR 804) spectrometers and CRRES ion mass spectrometer (IMS-HI) (ONR 307-8-3) ion composition and ENA instrument. The IMS-HI neutral atom spectrometer covers the energy range from 20 to 1,500 keV with a geometrical factor of 10[sub [minus]3] cm[sup 2] sr and uses a 7-kG magnetic field to screen out protons less than about 50 MeV. During the strong magnetic storm of 24 March 1991 the first ENA and ion mass composition measurements were obtained of ring current particles below the inner belt and these fluxes are compared to the IMS-HI flux measurements in the ring current. Recently, an advanced spectrometer, the Source/Loss-cone Energetic Particle Spectrometer (SEPS), has been developed to image electrons, ions, and neutrals on the despun platform of the POLAR satellite ([approximately]1.8 [times] 9 R[sub e]) for launch in the mid 1990s as part of NASA's International Solar Terrestrial Physics/Global Geospace Science (ISTP/GGS) program.

Voss, H.D.; Mobilia, J.; Collin, H.L.; Imhof, W.L. (Lockheed Palo Alto Research Lab., CA (United States). Space Sciences Lab.)

1993-12-01

409

Evaluation of Long-Term Cloud-Resolving Model Simulations Using Satellite Radiance Observations and Multi-Frequency Satellite Simulators  

NASA Technical Reports Server (NTRS)

This paper proposes a methodology known as the Tropical Rainfall Measuring Mission (TRMM) Triple-Sensor Three-step Evaluation Framework (T3EF) for the systematic evaluation of precipitating cloud types and microphysics in a cloud-resolving model (CRM). T3EF utilizes multi-frequency satellite simulators and novel statistics of multi-frequency radiance and backscattering signals observed from the TRMM satellite. Specifically, T3EF compares CRM and satellite observations in the form of combined probability distributions of precipitation radar (PR) reflectivity, polarization-corrected microwave brightness temperature (Tb), and infrared Tb to evaluate the candidate CRM. T3EF is used to evaluate the Goddard Cumulus Ensemble (GCE) model for cases involving the South China Sea Monsoon Experiment (SCSMEX) and Kwajalein Experiment (KWAJEX). This evaluation reveals that the GCE properly captures the satellite-measured frequencies of different precipitating cloud types in the SCSMEX case but underestimates the frequencies of deep convective and deep stratiform types in the KWAJEX case. Moreover, the GCE tends to simulate excessively large and abundant frozen condensates in deep convective clouds as inferred from the overestimated GCE-simulated radar reflectivities and microwave Tb depressions. Unveiling the detailed errors in the GCE s performance provides the best direction for model improvements.

Matsui, Toshihisa; Zeng, Xiping; Tao, Wei-Kuo; Masunaga, Hirohiko; Olson, William S.; Lang, Stephen

2008-01-01

410

An analysis of the Seasat Satellite Data Distribution System  

NASA Technical Reports Server (NTRS)

A computerized data distribution network for remote accessing of Seasat generated data is described. The service is intended as an experiment to determine user needs and operational abilities for utilizing on-line satellite generated oceanographic data. Synoptic weather observations are input to the U.S. Fleet Numerical Oceanographic Central for preparation and transfer to a PDP 11/60 central computer, from which all access trunks originate. The data available includes meteorological and sea-state information in the form of analyses and forecasts, and users are being monitored for reactions to the system design, data products, system operation, and performance evaluation. The system provides data on sea level and upper atmospheric pressure, sea surface temperature, wind magnitude and direction, significant wave heights, direction, and periods, and spectral wave data. Transmissions have a maximum rate of 1.1 kbit/sec over the telephone line.

Ferrari, A. J.; Renfrow, J. T.

1980-01-01

411

The trapped He flux dynamics observed on the TSUBASA satellite  

NASA Astrophysics Data System (ADS)

TSUBASA satellite was launched on February 2002. TSUBASA is placed in a geostationary transfer orbit having roughly a perigee of 500 km, an apogee of 37,000km, a 28.5 inclination, and a 645 minute period. The Standard Dose Monitor (SDOM) onboard TSUBASA has carried out measurements of energetic electrons, protons, and alpha particles. He flux distribution greatly changed the substorm on April 19, 2001 event for the boundary. Possible source of the fluxes including remnants of solar particle population trapped during substroms, acceleration of hot plasma from the outer magnetosphere, and pitch-angle scattering from the top of the magnetic field line are discussed.

Matsumoto, H.

2002-12-01

412

An observation of a mutual event between two satellites of Uranus  

NASA Astrophysics Data System (ADS)

We present observations of the occultation of Umbriel by Oberon o