Sample records for satellite-based terrestrial communication

  1. Design of Optimal Topology of Satellite-Based Terrestrial Communication Networks

    E-print Network

    Verkhovsky, Boris S

    2010-01-01

    Topological design of terrestrial networks for communication via satellites is studied in the paper. Quantitative model of the network cost-analysis minimizing the total transmission and switching cost is described. Several algorithms solving combinatorial problem of the optimal topology design based on binary partitioning, a minimax parametric search and dynamic programming are developed by the author and demonstrated with a numeric example. Analysis of average complexity of the minimax parametric search algorithm is also provided.

  2. Integration between terrestrial-based and satellite-based land mobile communications systems

    NASA Technical Reports Server (NTRS)

    Arcidiancono, Antonio

    1990-01-01

    A survey is given of several approaches to improving the performance and marketability of mobile satellite systems (MSS). The provision of voice/data services in the future regional European Land Mobile Satellite System (LMSS), network integration between the Digital Cellular Mobile System (GSM) and LMSS, the identification of critical areas for the implementation of integrated GSM/LMSS areas, space segment scenarios, LMSS for digital trunked private mobile radio (PMR) services, and code division multiple access (CDMA) techniques for a terrestrial/satellite system are covered.

  3. Low earth orbit satellite based communication systems — Research opportunities

    Microsoft Academic Search

    Bezalel Gavish

    1997-01-01

    Telecommunication systems are undergoing revolutionary changes that are transforming society, changing the way in which industrial and service organizations operate, and are having a profound effect on the daily life of individuals. Low earth orbit satellite (LEOS) based communication systems are a new and exciting endeavor in reshaping the global communication network and the services that it provides. Huge investments

  4. Spacetime effects on satellite-based quantum communications

    E-print Network

    Bruschi, David Edward; Fuentes, Ivette; Jennewein, Thomas; Razavi, Mohsen

    2013-01-01

    We investigate the effects of space-time curvature on space-based quantum communication protocols. We analyze tasks that require either the exchange of single photons in a certain entanglement distribution protocol or beams of light in a continuous-variable quantum key distribution scheme. We find that gravity affects the propagation of photons, therefore acting as a noisy channel for the transmission of information. The effects can be measured with current technology.

  5. Spacetime effects on satellite-based quantum communications

    E-print Network

    David Edward Bruschi; Tim Ralph; Ivette Fuentes; Thomas Jennewein; Mohsen Razavi

    2014-04-26

    We investigate the consequences of space-time being curved on space-based quantum communication protocols. We analyze tasks that require either the exchange of single photons in a certain entanglement distribution protocol or beams of light in a continuous-variable quantum key distribution scheme. We find that gravity affects the propagation of photons, therefore adding additional noise to the channel for the transmission of information. The effects could be measured with current technology.

  6. Terrestrial mobile communications

    NASA Astrophysics Data System (ADS)

    Rogard, R.; Steciw, A.

    1986-11-01

    Current and future mobile communications services in Europe are described, along with the technologies for meeting the market needs. A 450 MHz cellular system began operations in Scandinavian countries in 1981, and two 900 MHz systems entered service in the United Kingdom in 1985. Similar systems are being implemented in most European countries. Coding and access schemes are being studied for a pan-European 900 MHz system. Satellites can complement the system by providing service in coastal waters, regions of economic importance to Europe, and sparsely-populated areas. Improvements in vocodors, receiver gain, and technologies for the less-congested 14/11 or 30/20 GHz voice and data links are necessary. ESA studies with the Marecs satellite, preparatory to launch of a prototype mobile communication link, are summarized.

  7. Trellis coding with Continuous Phase Modulation (CPM) for satellite-based land-mobile communications

    NASA Technical Reports Server (NTRS)

    1989-01-01

    This volume of the final report summarizes the results of our studies on the satellite-based mobile communications project. It includes: a detailed analysis, design, and simulations of trellis coded, full/partial response CPM signals with/without interleaving over various Rician fading channels; analysis and simulation of computational cutoff rates for coherent, noncoherent, and differential detection of CPM signals; optimization of the complete transmission system; analysis and simulation of power spectrum of the CPM signals; design and development of a class of Doppler frequency shift estimators; design and development of a symbol timing recovery circuit; and breadboard implementation of the transmission system. Studies prove the suitability of the CPM system for mobile communications.

  8. Estimating Leaf Area Index from Terrestrial Lidar and Satellite Based Vegetation Indices Using Bayesian Inference

    NASA Astrophysics Data System (ADS)

    Ilangakoon, N. T.; Gorsevski, P.; Simic, A.

    2014-12-01

    Leaf area index (LAI) is an important indicator of ecosystem conditions and a key biophysical variable to many ecosystem models. The LAI in this study was measured by Leica ScanStation C 10 Terrestrial Laser Scanner (TLS) and a hand-held Li-Cor LAI-2200 Plant Canopy Analyzer for understanding differences derived from the two sensors. A total of six different LAI estimates were generated using different methods for the comparisons. The results suggested that there was a reasonable agreement (i.e., correlations r > 0.50) considering a total of 30 plots and use of very different in situ foliage measurements. . The predicted LAI from spectral vegetation indices including WDVI, DVI, NDVI, SAVI, and PVI3 which were derived from Landsat TM imagery were used to identify statistical relationships and for the development of the Bayesian inference model. The Bayesian Linear Regression (BLR) approach was used to scale up LAI estimates and to produce continuous field surfaces for the Oak Openings Region in NW Ohio. The results from the BLR provided details about the parameter uncertainties but also insight about the potential that different LAIs can be used to predict foliage that has been adjusted by removing the wooden biomass with reasonable accuracy. For instance, the modeled residuals associated with the LAI estimates from TLS orthographic projection that consider only foliage had the lowest overall model uncertainty with lowest error and residual dispersion range among the six spatial LAI estimates. The deviation from the mean LAI prediction map derived from the six estimates hinted that sparse and open areas that relate to vegetation structure were associated with the highest error. However, although in many studies TLS has been shown to hold a great potential for quantifying vegetation structure, in this study the quantified relationship between LAI and the vegetation indices did not yield any statistical relationship that needs to be further explored.

  9. Evaluation of hydrological balance in the eastern Amazon using a terrestrial ecosystem model, and satellite-based evapotranspiration (MODIS) and terrestrial water storage (GRACE)

    NASA Astrophysics Data System (ADS)

    Panday, P. K.; Coe, M. T.; Macedo, M.; Beck, P.

    2013-12-01

    High historical deforestation rates and a rapidly changing agricultural landscape may dramatically alter the energy and water balance of the eastern Amazon basin. Understanding the surface water dynamics and hydrological balance of the region is critical for accurately assessing the historical and potential future impacts of deforestation, land-use change, and land management practices. We examine the water balance of the Xingu river basin by combining the IBIS (Integrated Biosphere Simulator) terrestrial ecosystem model with satellite-based models of evapotranspiration (MOD16) and terrestrial water storage (GRACE). IBIS simulations were forced with prescribed climate to produce modeled evapotranspiration and runoff, which were then compared with MODIS evapotranspiration and observed discharge at Altamira (PA, Brazil). Results from both satellite observations and model simulations support earlier studies demonstrating that dry-season evapotranspiration is higher than wet-season evapotranspiration in the wetter forests of the northern Xingu basin, while the contrary is true in the seasonally dry forests of the southern Xingu. Seasonal variation in modeled soil water storage agrees with the GRACE measurements in both timing and magnitude. Soil moisture anomalies averaged over the Xingu basin suggest that annual changes in soil water storage account for a large part of the interannual variation in observed discharge. Field measurements of discharge and soil moisture in the southern Xingu also support the findings that changes in soil water storage drive inter-annual variations in river discharge. Figure 1. Comparison of observed discharge at Altamira (Pará, Brazil) against MODIS- derived P-E (PCRU-MODISET), IBIS simulated discharge, IBIS (PCRU-ETIBIS), and IBIS (PCRU-ETIBIS- ? Soil moisture IBIS). The bottom panel shows annual basin precipitation from Climatic Research Unit (CRU) climatological data for the 2000-2008 period

  10. Satellite communication system integrated into terrestrial ISDN

    Microsoft Academic Search

    TORU OTSU; KAZUHIRO NAGAYAMA; AKIRA KUROKAWA; HIROSHI NAKASHIMA; MASAHIRO UMEHIRA

    2000-01-01

    This paper presents an advanced satellite communication system named DYANET II. This system uses satellite channels as subscriber lines for ISDN customers as well as trunk circuits for overflow traffic. The system can offer the same ISDN services to satellite customers as those available to terrestrial subscribers in terms of numbering, signaling, and charging systems as well as user-network interfaces.

  11. Satellite-based quantum communication terminal employing state-of-the-art technology

    Microsoft Academic Search

    Martin Pfennigbauer; Markus Aspelmeyer; Walter R. Leeb; Guy Baister; Thomas Dreischer; Thomas Jennewein; Gregor Neckamm; Josep M. Perdigues; Harald Weinfurter; Anton Zeilinger

    2005-01-01

    Feature Issue on Optical Wireless Communications (OWC) We investigate the design and the accommodation of a quantum communication transceiver in an existing classical optical communication terminal on board a satellite. Operation from a low earth orbit (LEO) platform (e.g., the International Space Station) would allow transmission of single photons and pairs of entangled photons to ground stations and hence permit

  12. Perceived issues associated with military use of satellite based personal communications systems

    Microsoft Academic Search

    A. Bartko; A. Q. Le; T. N. Thomas

    1995-01-01

    As charged by Congress and the Office of the Secretary of Defense, the Defense Information Systems Agency (DISA) created the Commercial Satellite Communications Initiatives (CSCI) program. The CSCI program's purpose is to assess the use of available and planned commercial communications satellites to fulfill, in a cost-effective manner, certain military communications that would be otherwise provided by Government satellite systems.

  13. A jitter rejection technique in a satellite-based laser communication system

    Microsoft Academic Search

    Victor A. Skormin; Mark A. Tascillo; Donald J. Nicholson

    1993-01-01

    A technique, resulting in the significant reduction of negative effects of satellite jitter on the accuracy of laser beam positioning in communication systems, is presented. It implies application of vibration monitoring instrumentation for estimation of the motion components constituting jitter. A self-tuning feedforward jitter compensation scheme is introduced to the existing mirror positioning control systems. The technique is verified by

  14. Radio communications with extra-terrestrial civilizations

    NASA Technical Reports Server (NTRS)

    Kotelnikov, V. A.

    1974-01-01

    Communications between civilizations within our galaxy at the present level of radio engineering is possible, although civilizations must begin to search for each other to achieve this. If an extra-terrestrial civilization possessing a technology at our level wishes to make itself known and will transmit special radio signals to do this, then it can be picked up by us at a distance of several hundreds of light years using already existing radio telescopes and specially built radio receivers. If it wishes, this civilization can also send us information without awaiting our answer.

  15. Communication technology is integral to most aerospace systems. Communication satel-lites bring us live coverage of events from around the world, deep-space communication

    E-print Network

    Peraire, Jaime

    lacking terrestrial communication infrastructure, satellite-based networks provide the only viable mechanism for vital communication ser- vices. For example, the U.S. military depends on satellites for rapidly deployable, robust, and reliable communications during military operations, and satellites

  16. A satellite based telemetry link for a UAV application

    NASA Technical Reports Server (NTRS)

    Bloise, Anthony

    1995-01-01

    The requirements for a satellite based communication facility to service the needs of the Geographical Information System (GIS) data collection community are addressed in this paper. GIS data is supplied in the form of video imagery at sub-television rates in one or more spectral bands / polarizations laced with a position correlated data stream. The limitations and vicissitudes of using a terrestrial based telecommunications link to collect GIS data are illustrated from actual mission scenarios. The expectations from a satellite based communications link by the geophysical data collection community concerning satellite architecture, operating bands, bandwidth, footprint agility, up link and down link hardware configurations on the UAV, the Mobile Control Vehicle and at the Central Command and Data Collection Facility comprise the principle issues discussed in the first section of this paper. The final section of the paper discusses satellite based communication links would have an increased volume and scope of services the GIS data collection community could make available to the GIS user community, and the price the data collection community could afford to pay for access to the communication satellite described in the paper.

  17. Application of deep convective cloud albedo observation to satellite-based study of the terrestrial atmosphere: monitoring the stability of spaceborne measurements and assessing absorption anomaly

    Microsoft Academic Search

    Yongxiang Hu; Bruce A. Wielicki; Ping Yang; B. Lin; D. F. Young

    2004-01-01

    An objective method is developed to monitor the stability of spaceborne instruments, aimed at distinguishing climate trend from instrument drift in satellite-based climate observation records. This method is based on four-years of Clouds and the Earth's Radiant Energy System (CERES) broadband observations of deep convective cloud systems with cloud-top temperature lower than 205 K and with large optical depths. The

  18. A Hybrid Satellite-Terrestrial Approach to Aeronautical Communication Networks

    NASA Technical Reports Server (NTRS)

    Kerczewski, Robert J.; Chomos, Gerald J.; Griner, James H.; Mainger, Steven W.; Martzaklis, Konstantinos S.; Kachmar, Brian A.

    2000-01-01

    Rapid growth in air travel has been projected to continue for the foreseeable future. To maintain a safe and efficient national and global aviation system, significant advances in communications systems supporting aviation are required. Satellites will increasingly play a critical role in the aeronautical communications network. At the same time, current ground-based communications links, primarily very high frequency (VHF), will continue to be employed due to cost advantages and legacy issues. Hence a hybrid satellite-terrestrial network, or group of networks, will emerge. The increased complexity of future aeronautical communications networks dictates that system-level modeling be employed to obtain an optimal system fulfilling a majority of user needs. The NASA Glenn Research Center is investigating the current and potential future state of aeronautical communications, and is developing a simulation and modeling program to research future communications architectures for national and global aeronautical needs. This paper describes the primary requirements, the current infrastructure, and emerging trends of aeronautical communications, including a growing role for satellite communications. The need for a hybrid communications system architecture approach including both satellite and ground-based communications links is explained. Future aeronautical communication network topologies and key issues in simulation and modeling of future aeronautical communications systems are described.

  19. Leo-Based Optical/Microwave Terrestrial Communications

    E-print Network

    Andrew Meulenberg; Rahul Suresh; Shivram Ramanathan

    2010-09-28

    We propose a LEO-based communication system that is built by deploying circum-terra, optic fibers connecting hundreds of small (perhaps) phased-array-communications and RF-signal-transfer antennas around the earth on multiple rings. The proposed LEO-earth connection will be through microwave links (Ku or low-Ka band) and many of the ISL's through the optic-fiber rings. Inter-ring connectivity could be with either high-Ka band or optical (laser) links. The initial ring would serve to complement existing terrestrial fiber networks; but, the system would expand with additional rings into non-equatorial planes to provide global connectivity. The proposed system would make use of connectivity & broadcasting capability of satellite constellations as well as the high throughput point-to-point capability of optic-fiber systems. The advantages, options, and economics of the proposed LEO optic-fiber / microwave communication system over existing terrestrial- and space-communication systems (of similar functionality) as well as the future development of the system are dealt with in the paper.

  20. Leo-Based Optical/Microwave Terrestrial Communications

    E-print Network

    Meulenberg, Andrew; Ramanathan, Shivram

    2010-01-01

    We propose a LEO-based communication system that is built by deploying circum-terra, optic fibers connecting hundreds of small (perhaps) phased-array-communications and RF-signal-transfer antennas around the earth on multiple rings. The proposed LEO-earth connection will be through microwave links (Ku or low-Ka band) and many of the ISL's through the optic-fiber rings. Inter-ring connectivity could be with either high-Ka band or optical (laser) links. The initial ring would serve to complement existing terrestrial fiber networks; but, the system would expand with additional rings into non-equatorial planes to provide global connectivity. The proposed system would make use of connectivity & broadcasting capability of satellite constellations as well as the high throughput point-to-point capability of optic-fiber systems. The advantages, options, and economics of the proposed LEO optic-fiber / microwave communication system over existing terrestrial- and space-communication systems (of similar functionality...

  1. Satellite-based terrestrial production efficiency modeling

    Microsoft Academic Search

    Ian McCallum; Wolfgang Wagner; Christiane Schmullius; Anatoly Shvidenko; Michael Obersteiner; Steffen Fritz; Sten Nilsson

    2009-01-01

    Production efficiency models (PEMs) are based on the theory of light use efficiency (LUE) which states that a relatively constant relationship exists between photosynthetic carbon uptake and radiation receipt at the canopy level. Challenges remain however in the application of the PEM methodology to global net primary productivity (NPP) monitoring. The objectives of this review are as follows: 1) to

  2. Performance of Duplex Communication between a Leo Satellite and Terrestrial Location Using a Geo Constellation

    NASA Technical Reports Server (NTRS)

    Robinson, Daryl C.; Konangi, Vijay K.; Wallett, Thomas M.

    1998-01-01

    A network comprised of a terrestrial site, a constellation of three GEO satellites and a LEO satellite is modeled and simulated. Continuous communication between the terrestrial site and the LEO satellite is facilitated by the GEO satellites. The LEO satellite has the orbital characteristics of the International Space Station. Communication in the network is based on TCP/IP over ATM, with the ABR service category providing the QoS, at OC-3 data rate. The OSPF protocol is used for routing. We simulate FTP file transfers, with the terrestrial site serving as the client and the LEO satellite being the server. The performance characteristics are presented.

  3. Wireless infrared communications for space and terrestrial applications

    NASA Technical Reports Server (NTRS)

    Crimmins, James W.

    1993-01-01

    Voice and data communications via wireless (and fiberless) optical means has been commonplace for many years. However, continuous advances in optoelectronics and microelectronics have resulted in significant advances in wireless optical communications over the last decade. Wilton has specialized in diffuse infrared voice and data communications since 1979. In 1986, NASA Johnson Space Center invited Wilton to apply its wireless telecommunications and factory floor technology to astronaut voice communications aboard the shuttle. In September, 1988 a special infrared voice communications system flew aboard a 'Discovery' Shuttle mission as a flight experiment. Since then the technology has been further developed, resulting in a general purpose of 2Mbs wireless voice/data LAN which has been tested for a variety of applications including use aboard Spacelab. Funds for Wilton's wireless IR development were provided in part by NASA's Technology Utilization Office and by the NASA Small Business Innovative Research Program. As a consequence, Wilton's commercial product capability has been significantly enhanced to include diffuse infrared wireless LAN's as well as wireless infrared telecommunication systems for voice and data.

  4. Terrestrial Communications Systems in Distance Education. A Reference Booklet.

    ERIC Educational Resources Information Center

    Worthington, Ross

    This booklet is intended as a reference on the application of the technology of communication systems to distance education. An introductory section addresses the nature of the interaction imposed by use of various technologies. The next section overviews current telecommunications applications based on these major technologies: radio, television…

  5. Hybrid terrestrial/satellite networks and interoperability among public safety communication systems

    NASA Astrophysics Data System (ADS)

    Deobald, Brian M.

    2005-06-01

    A recent FCC decision1 has validated a new architecture with the potential to provide all of North America with an unusually broad and powerful wireless communications system. This architecture permits an existing allocation of mobile satellite spectrum to power a hybrid network, comprised of both terrestrial and satellite components. A satellite provides ubiquitous coverage, switching to a terrestrial-based cellular technology when in urban areas. The terrestrial component also provides capacity in areas of high demand. This ultra wide-area hybrid network, in turn, can act as a hub in an interlocking system of networks, incorporating public safety LMRs. The applicability of this system to homeland security should be obvious. It works nearly everywhere. It continues working even when towers are down throughout a wide area. It works with a conventional mobile device in a functionally transparent manner, providing first responders with interoperability, coverage, and redundancy needed to execute both their day-to-day and exigent responsibilities.

  6. Satellite-based laser windsounder

    SciTech Connect

    Schultz, J.F.; Czuchlewski, S.J.; Quick, C.R. [and others

    1997-08-01

    This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project`s primary objective is to determine the technical feasibility of using satellite-based laser wind sensing systems for detailed study of winds, aerosols, and particulates around and downstream of suspected proliferation facilities. Extensive interactions with the relevant operational organization resulted in enthusiastic support and useful guidance with respect to measurement requirements and priorities. Four candidate wind sensing techniques were evaluated, and the incoherent Doppler technique was selected. A small satellite concept design study was completed to identify the technical issues inherent in a proof-of-concept small satellite mission. Use of a Mach-Zehnder interferometer instead of a Fabry-Perot would significantly simplify the optical train and could reduce weight, and possibly power, requirements with no loss of performance. A breadboard Mach-Zehnder interferometer-based system has been built to verify these predictions. Detailed plans were made for resolving other issues through construction and testing of a ground-based lidar system in collaboration with the University of Wisconsin, and through numerical lidar wind data assimilation studies.

  7. Satellite/Terrestrial Networks: End-to-End Communication Interoperability Quality of Service Experiments

    NASA Technical Reports Server (NTRS)

    Ivancic, William D.

    1998-01-01

    Various issues associated with satellite/terrestrial end-to-end communication interoperability are presented in viewgraph form. Specific topics include: 1) Quality of service; 2) ATM performance characteristics; 3) MPEG-2 transport stream mapping to AAL-5; 4) Observation and discussion of compressed video tests over ATM; 5) Digital video over satellites status; 6) Satellite link configurations; 7) MPEG-2 over ATM with binomial errors; 8) MPEG-2 over ATM channel characteristics; 8) MPEG-2 over ATM over emulated satellites; 9) MPEG-2 transport stream with errors; and a 10) Dual decoder test.

  8. Enhancing Optical Signal-to-Noise Ratio in Terrestrial Cascaded EDFAs Fiber Optic Communication Links using Hybrid Fiber Amplifier

    Microsoft Academic Search

    Tuan Nguyen Van; Hong Do Viet

    2009-01-01

    In this paper, we propose calculating models of Terrestrial DWDM cascaded EDFAs Fiber Optic Communication Links using Hybird Fiber Amplifier (HFA) including combination of Distributed Raman Amplifier (DRA) and EDFA, and build algorithm charts to optimize parameters including signal power per channel launched fiber, EDFAs gain, pump power of Raman amplifier for improving optical Signal-to-Noise ratio (OSNR) at the end

  9. Introduction of a terrestrial free-space optical communications network facility: IN-orbit and Networked Optical ground stations experimental Verification Advanced testbed (INNOVA)

    NASA Astrophysics Data System (ADS)

    Toyoshima, Morio; Munemasa, Yasushi; Takenaka, Hideki; Takayama, Yoshihisa; Koyama, Yoshisada; Kunimori, Hiroo; Kubooka, Toshihiro; Suzuki, Kenji; Yamamoto, Shinichi; Taira, Shinichi; Tsuji, Hiroyuki; Nakazawa, Isao; Akioka, Maki

    2014-03-01

    A terrestrial free-space optical communications network facility, named IN-orbit and Networked Optical ground stations experimental Verification Advanced testbed (INNOVA) is introduced. Many demonstrations have been conducted to verify the usability of sophisticated optical communications equipment in orbit. However, the influence of terrestrial weather conditions remains as an issue to be solved. One potential solution is site diversity, where several ground stations are used. In such systems, implementing direct high-speed optical communications links for transmission of data from satellites to terrestrial sites requires that links can be established even in the presence of clouds and rain. NICT is developing a terrestrial free-space optical communications network called INNOVA for future airborne and satellitebased optical communications projects. Several ground stations and environmental monitoring stations around Japan are being used to explore the site diversity concept. This paper describes the terrestrial free-space optical communications network facility, the monitoring stations around Japan for free-space laser communications, and potential research at NICT.

  10. The Upper Valanginian (Early Cretaceous) positive carbon-isotope event recorded in terrestrial plants [rapid communication

    Microsoft Academic Search

    Darren R. Gröcke; Gregory D. Price; Stuart A. Robinson; Evgenij Y. Baraboshkin; Jörg Mutterlose; Alastair H. Ruffell

    2005-01-01

    Our understanding of the ancient ocean-atmosphere system has focused on oceanic proxies. However, the study of terrestrial proxies is equally necessary to constrain our understanding of ancient climates and linkages between the terrestrial and oceanic carbon reservoirs. We have analyzed carbon isotope ratios from fossil plant material through the Valanginian and Lower Hauterivian from a shallow-marine, ammonite-constrained succession in the

  11. Spectral model of optical scintillation for terrestrial free-space optical communication link design

    NASA Astrophysics Data System (ADS)

    Kim, Kyung-Hwan; Higashino, Takeshi; Tsukamoto, Katsutoshi; Komaki, Shozo; Kazaura, Kamugisha; Matsumoto, Mitsuji

    2011-03-01

    Since a deep and long-term fading in optical intensity results in considerable burst errors in the data, a terrestrial free-space optical (FSO) system has to be designed with consideration of a frequency characteristic of optical scintillation to achieve high quality wireless services over the link. In designing a terrestrial FSO link, we had better design the system considering variations caused by some slow time-varying parameters. This paper proposes a Butterworth-type spectral model of optical scintillation to design a terrestrial FSO link, which enables us to estimate the power spectral density of optical scintillation in a current optical wireless channel when time zone and weather parameters, such as temperature and rainfall intensity, are given. The spectral parameters of optical scintillation, cut-off frequency, and spectral slope are estimated from the data obtained in the experiment, and then their dependencies on time zone, temperature, and rainfall intensity are examined.

  12. Satellite-based quantum clock synchronization

    E-print Network

    Wang, Jieci; Jing, Jiliang; Fan, Heng

    2015-01-01

    We propose a practical satellite-based quantum clock synchronization scheme with dispersion cancellation and by taking into account effects of gravitational frequency shift of the Earth. Two frequency entangled pulses are employed to synchronize two clocks, one at a ground station and the other at a satellite. The time discrepancy of the two clocks is introduced into the pulses by moving mirrors and is extracted by measuring the coincidence rate of the pulses in the interferometer. We find that the pulses are distorted due to effects of the gravitational frequency shift when they propagate between the Earth and the satellite. It is shown that the coincidence rate as well as precision of the time discrepancy are remarkably affected by gravitational frequency shift effects both for the low earth orbits satellite and geostationary earth orbits satellite cases. We also find that the precision of the clock synchronization are sensitive to the source parameters and the altitude of the satellite. Our proposal can be...

  13. A satellite-based radar wind sensor

    NASA Technical Reports Server (NTRS)

    Xin, Weizhuang

    1991-01-01

    The objective is to investigate the application of Doppler radar systems for global wind measurement. A model of the satellite-based radar wind sounder (RAWS) is discussed, and many critical problems in the designing process, such as the antenna scan pattern, tracking the Doppler shift caused by satellite motion, and backscattering of radar signals from different types of clouds, are discussed along with their computer simulations. In addition, algorithms for measuring mean frequency of radar echoes, such as the Fast Fourier Transform (FFT) estimator, the covariance estimator, and the estimators based on autoregressive models, are discussed. Monte Carlo computer simulations were used to compare the performance of these algorithms. Anti-alias methods are discussed for the FFT and the autoregressive methods. Several algorithms for reducing radar ambiguity were studied, such as random phase coding methods and staggered pulse repitition frequncy (PRF) methods. Computer simulations showed that these methods are not applicable to the RAWS because of the broad spectral widths of the radar echoes from clouds. A waveform modulation method using the concept of spread spectrum and correlation detection was developed to solve the radar ambiguity. Radar ambiguity functions were used to analyze the effective signal-to-noise ratios for the waveform modulation method. The results showed that, with suitable bandwidth product and modulation of the waveform, this method can achieve the desired maximum range and maximum frequency of the radar system.

  14. CO2 Sequestration Leak Detection Using Satellite-Based Sensors

    NASA Astrophysics Data System (ADS)

    Brewer, B.; Hoffmann, G. D.; Silver, E. A.; Dileonardo, C.; Vigil, S. A.; Henderson, J.

    2011-12-01

    Geologic carbon sequestration may present the risk of carbon dioxide (CO2) leakage into the atmosphere. Ground and aerial-based methods of CO2 leak detection tend to be expensive and/or site-specific. Using satellites for leak detection would allow global coverage with low long-term maintenance costs. Two satellite-based sensors for measuring atmospheric CO2 concentration are currently in orbit, namely SCIAMACHY and GOSAT. Within the next decade additional sensors are expected to be available, including OCO-2 and CarbonSat. Using the terrestrial footprint size of each instrument we estimated the minimum CO2 leak rate each instrument would be capable of detecting. The higher spatial resolutions anticipated for OCO-2 and CarbonSat should allow these sensors to detect leaks 1-2 orders of magnitude smaller than those detectable using SCIAMACHY or GOSAT, which were designed to examine large-scale patterns of CO2 distribution. The sparse spatial coverage by GOSAT makes it unviable for monitoring sequestration sites. We have developed several geospatial analytical techniques for leak/plume detection using SCIAMACHY data in the vicinity of large, isolated CO2 sources such as Jim Bridger Coal Plant, Wyoming (43 ktons/day). Techniques used include 1) comparing CO2 mixing ratio (xCO2) in subregions relative to the point source's location, 2) charting of xCO2 as a function of distance from the source and wind direction, 3) regional plume detection using linear transects perpendicular to wind direction, and 4) aggregation of CO2 data by prevailing wind direction. While these techniques failed to positively identify increased CO2 concentration from the Jim Bridger Coal Plant using SCIAMACHY data, we believe these techniques could be successfully applied to data with higher spatial resolution.

  15. Satellite-Based Educational Services. Technical Memorandum.

    ERIC Educational Resources Information Center

    Operations Research, Inc., Silver Spring, MD.

    This memorandum contains engineering information relevant to the use of communication satellites for educational purposes. Information is provided for ground terminals as well as satellites. Satellite related issues addressed include: (1) expected life of service of various satellites, (2) constraints on the availability of the satellites, (3)…

  16. Changes in Hemispheric Snow Accumulation Based on CMIP5 Simulations and Satellite-Based Data

    NASA Astrophysics Data System (ADS)

    Luojus, Kari; Pulliainen, Jouni; Cohen, Juval; Ikonen, Jaakko; Takala, Matias; Lemmetyinen, Juha; Smolander, Tuomo; Derksen, Chris

    2015-04-01

    The European Space Agency (ESA) GlobSnow project has produced a daily hemisphere-scale satellite-based snow water equivalent (SWE) data record spanning more than 30-years. The GlobSnow SWE record, based on methodology by Pulliainen [1] utilizes a data-assimilation based approach for the estimation of SWE which was shown to be superior to the approaches depending solely on satellite-based data [2]. The GlobSnow SWE data record is based on the time-series of measurements by three different space-borne passive radiometers (SMMR, SSM/I and SSMIS) measuring in the microwave region, spanning from 1980 to present day at a spatial resolution of approximately 25 km. We briefly introduce the GlobSnow hemispherical dataset on SWE produced using a variational assimilation scheme combining satellite data with ground-based observations that has been used to construct a 30+ years daily time-series of terrestrial snow cover. We present the comparison of GlobSnow SWE dataset with climate model simulations from the CMIP5 archive. The objective of this work is to investigate the performance of the CMIP5 models in capturing the evolution of hemispheric scale snow conditions for the period of 1980 to 2013. The climate model simulations on snow cover extent, snow depth and snow water equivalent are assessed against an ensemble of GlobSnow SWE datasets compiled from different GlobSnow product versions. The future projections of the CMIP5 model simulations on snow cover are also investigated. The assessment indicates a decreasing trend in spring time hemispherical snow mass for the period of 1980 to 2013 in remote-sensing based data record. The inter-comparison of satellite-based record and climate model simulations show large differences in autumn, winter and spring time Hemispherical scale snow conditions. Similar trends of decreasing snow cover are also seen in the investigated CMIP5 models, although there is a notable variance between different models. Some of the models capture the overall hemispherical snow mass more accurately than others. In general the winter months (December, January and February) seem to be rather well captured, while the spring season, (March, April and May) appears more challenging for the climate models. The results show that the CMIP5 ensemble average is rather close to the satellite-based data record for the overlapping time period during the winter months on January and February. For March the CMIP5 ensemble average is clearly higher than that of the satellite-based record. For April, the CMIP5 ensemble average shows a significant over estimation when compared with the satellite-based data. This indicates that the satellite-based and CMIP5 based data are agreeing relatively well regarding the overall hemispherical snow mass for the winter months, but a vast majority of the CMIP5 models are over estimating the hemispheric snow mass during the spring snow melt season. Also the inter-annual variability of snow cover is clearly higher in the observation-based record, compared with climate models. REFERENCES [1] Pulliainen, J. Mapping of snow water equivalent and snow depth in boreal and sub-arctic zones by assimilating space-borne microwave radiometer data and ground-based observations. Remote Sensing of Environment. 101: 257-269. DOI: 10.1016/j.rse.2006.01.002. [2] Takala, M., Luojus, K., Pulliainen, J., Derksen, C., Lemmetyinen, J., Kärnä, J.-P, Koskinen, J., Bojkov, B., "Estimating northern hemisphere snow water equivalent for climate research through assimilation of space-borne radiometer data and ground-based measurements", Remote Sensing of Environment, Vol. 115, Issue 12, 15 December 2011, Pages 3517-3529, ISSN 0034-4257, DOI: 10.1016/j.rse.2011.08.014.

  17. SATELLITE BASED SHORT-TERM FORECASTING OF SOLAR IRRADANCE

    E-print Network

    Heinemann, Detlev

    into existing energy supply structures. As far as short-term time horizons (up to 2h) are concerned, satelliteSATELLITE BASED SHORT-TERM FORECASTING OF SOLAR IRRADANCE - COMPARISON OF METHODS AND ERROR the development of the cloud structure. The accuracy of the predicted cloud images was analysed and compared

  18. "Globalstar, Iridium and other Satellite-Based Mobile Phone

    E-print Network

    1 "Globalstar, Iridium and other Satellite-Based Mobile Phone Systems: How Do they Work and Where formed in the early 90's ­ Iridium [LEO, intersatellite links] ­ Globalstar [LEO, satellite diversity in their Flying Machines Iridium LEO Polar TDMA Globalstar LEO Inclined CDMA ICO MEO Inclined Custom Constellation

  19. An energy-efficient architecture for multi-hop communication between rovers and satellites in extra-terrestrial surfaces

    Microsoft Academic Search

    Daniel Irwin; Hrishikesh Venkataraman; Gabriel-Miro Muntean

    2012-01-01

    Over the past three decades, several man-made vehicles have being sent into space to explore the extra-terrestrial bodies. As the search for water and other useful substances in the extra-terrestrial surfaces increases, this exploration activity is set to dramatically increase over the next decade (2020); with NASA planning to explore the surface of Mars, Moon and other planets and satellites.

  20. Automatic GPS satellite based subsidence measurements for Ekofisk

    SciTech Connect

    Mes, M.J.; Luttenberger, C.; Landau, H.; Gustavsen, K.

    1995-12-01

    A fully automatic procedure for the measurement of subsidence of many platforms in almost real time is presented. Such a method is important for developments which may be subject to subsidence and where reliable subsidence and rate measurements are needed for safety, planning of remedial work and verification of subsidence models. Automatic GPS satellite based subsidence measurements are made continuously on platforms in the North Sea Ekofisk Field area. A description of the system is given. The derivation of those parameters which give optimal measurement accuracy is described, the results of these derivations are provided. GPS satellite based measurements are equivalent to pressure gauge based platform subsidence measurements, but they are much cheaper to install and maintain. In addition, GPS based measurements are not subject to drift of any gauges. GPS measurements were coupled to oceanographic quantities such as the platform deck clearance. These quantities now follow from GPS based measurements.

  1. Satellite-Based Precipitation Measurement Using PERSIANN System

    Microsoft Academic Search

    Kuo-Lin Hsu; Soroosh Sorooshian

    PERSIANN (Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks) is a satellite-based\\u000a rainfall estimation algorithm. It uses local cloud textures from longwave infrared images of the geostationary environmental\\u000a satellites to estimate surface rainfall rates based on an artificial neural network algorithm. Model parameters are frequently\\u000a updated from rainfall estimates provided by low-orbital passive microwave rainfall estimates. The PERSIANN

  2. Operational Satellite-based Surface Oil Analyses (Invited)

    Microsoft Academic Search

    D. Streett; C. Warren

    2010-01-01

    During the Deepwater Horizon spill, NOAA imagery analysts in the Satellite Analysis Branch (SAB) issued more than 300 near-real-time satellite-based oil spill analyses. These analyses were used by the oil spill response community for planning, issuing surface oil trajectories and tasking assets (e.g., oil containment booms, skimmers, overflights). SAB analysts used both Synthetic Aperture Radar (SAR) and high resolution visible\\/near

  3. Internetworking satellite and local exchange networks for personal communications applications

    NASA Technical Reports Server (NTRS)

    Wolff, Richard S.; Pinck, Deborah

    1993-01-01

    The demand for personal communications services has shown unprecedented growth, and the next decade and beyond promise an era in which the needs for ubiquitous, transparent and personalized access to information will continue to expand in both scale and scope. The exchange of personalized information is growing from two-way voice to include data communications, electronic messaging and information services, image transfer, video, and interactive multimedia. The emergence of new land-based and satellite-based wireless networks illustrates the expanding scale and trend toward globalization and the need to establish new local exchange and exchange access services to meet the communications needs of people on the move. An important issue is to identify the roles that satellite networking can play in meeting these new communications needs. The unique capabilities of satellites, in providing coverage to large geographic areas, reaching widely dispersed users, for position location determination, and in offering broadcast and multicast services, can complement and extend the capabilities of terrestrial networks. As an initial step in exploring the opportunities afforded by the merger of satellite-based and land-based networks, several experiments utilizing the NASA ACTS satellite and the public switched local exchange network were undertaken to demonstrate the use of satellites in the delivery of personal communications services.

  4. ExtraTerrestrial Intelligence

    E-print Network

    Walter, Frederick M.

    SETI Search for ExtraTerrestrial Intelligence I know perfectly well that at this moment the whole, The Madwoman of Chaillot #12;Options Passive SETI: Listen Active SETI: Transmit #12;Search Strategies Suppose you find a civilization. You want to communicate. How? #12;Search Strategies There are two issues: A

  5. Adaptive sparse signal processing of satellite-based radio frequency (RF) recordings of lightning events

    NASA Astrophysics Data System (ADS)

    Moody, Daniela I.; Smith, David A.

    2014-05-01

    Ongoing research at Los Alamos National Laboratory studies the Earth's radio frequency (RF) background utilizing satellite-based RF observations of terrestrial lightning. Such impulsive events are dispersed through the ionosphere and appear as broadband nonlinear chirps at a receiver on-orbit. They occur in the presence of additive noise and structured clutter, making their classification challenging. The Fast On-orbit Recording of Transient Events (FORTE) satellite provided a rich RF lightning database. Application of modern pattern recognition techniques to this database may further lightning research in the scientific community, and potentially improve on-orbit processing and event discrimination capabilities for future satellite payloads. Conventional feature extraction techniques using analytical dictionaries, such as a short-time Fourier basis or wavelets, are not comprehensively suitable for analyzing the broadband RF pulses under consideration here. We explore an alternative approach based on non-analytical dictionaries learned directly from data, and extend two dictionary learning algorithms, K-SVD and Hebbian, for use with satellite RF data. Both algorithms allow us to learn features without relying on analytical constraints or additional knowledge about the expected signal characteristics. We then use a pursuit search over the learned dictionaries to generate sparse classification features, and discuss their performance in terms of event classification. We also use principal component analysis to analyze and compare the respective learned dictionary spaces to the real data space.

  6. Real-time adjustment of satellite-based rainfall estimates using the conditional mean: hydrological validation over French Guiana

    NASA Astrophysics Data System (ADS)

    Brochart, David; Andréassian, Vazken

    2015-04-01

    Satellite precipitation products are known to be plagued by large biases, which limit their use for operational applications. This communication presents a robust approach to adjust the satellite-based rainfall estimates using an intensity-dependent error correction curve, determined by taking the mean of historic ground measurements given the satellite estimates (conditional mean). We apply the procedure to seven satellite precipitation products over French Guiana and present a double validation, first at the raingage scale, and then at the catchment scale. Over the six catchments used here, the rainfall-runoff simulations are considerably improved when the correction is applied, outperforming the well-established quantile mapping technique.

  7. Airborne wireless communication systems, airborne communication methods, and communication methods

    DOEpatents

    Deaton, Juan D. (Menan, ID); Schmitt, Michael J. (Idaho Falls, ID); Jones, Warren F. (Idaho Falls, ID)

    2011-12-13

    An airborne wireless communication system includes circuitry configured to access information describing a configuration of a terrestrial wireless communication base station that has become disabled. The terrestrial base station is configured to implement wireless communication between wireless devices located within a geographical area and a network when the terrestrial base station is not disabled. The circuitry is further configured, based on the information, to configure the airborne station to have the configuration of the terrestrial base station. An airborne communication method includes answering a 911 call from a terrestrial cellular wireless phone using an airborne wireless communication system.

  8. Bias correction of satellite-based rainfall data

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Biswa; Solomatine, Dimitri

    2015-04-01

    Limitation in hydro-meteorological data availability in many catchments limits the possibility of reliable hydrological analyses especially for near-real-time predictions. However, the variety of satellite based and meteorological model products for rainfall provides new opportunities. Often times the accuracy of these rainfall products, when compared to rain gauge measurements, is not impressive. The systematic differences of these rainfall products from gauge observations can be partially compensated by adopting a bias (error) correction. Many of such methods correct the satellite based rainfall data by comparing their mean value to the mean value of rain gauge data. Refined approaches may also first find out a suitable time scale at which different data products are better comparable and then employ a bias correction at that time scale. More elegant methods use quantile-to-quantile bias correction, which however, assumes that the available (often limited) sample size can be useful in comparing probabilities of different rainfall products. Analysis of rainfall data and understanding of the process of its generation reveals that the bias in different rainfall data varies in space and time. The time aspect is sometimes taken into account by considering the seasonality. In this research we have adopted a bias correction approach that takes into account the variation of rainfall in space and time. A clustering based approach is employed in which every new data point (e.g. of Tropical Rainfall Measuring Mission (TRMM)) is first assigned to a specific cluster of that data product and then, by identifying the corresponding cluster of gauge data, the bias correction specific to that cluster is adopted. The presented approach considers the space-time variation of rainfall and as a result the corrected data is more realistic. Keywords: bias correction, rainfall, TRMM, satellite rainfall

  9. Terrestrial sequestration

    SciTech Connect

    Charlie Byrer

    2008-03-10

    Terrestrial sequestration is the enhancement of CO2 uptake by plants that grow on land and in freshwater and, importantly, the enhancement of carbon storage in soils where it may remain more permanently stored. Terrestrial sequestration provides an opportunity for low-cost CO2 emissions offsets.

  10. The use of satellite-based technology in developing countries

    E-print Network

    Wood, Danielle Renee

    2007-01-01

    Satellite technology in the areas of remote sensing, communication, and navigation can provide valuable information in a number of areas from business to disaster management to agriculture. There is great potential for ...

  11. Magnetic resonance imaging research in sub-Saharan Africa: challenges and satellite-based networking implementation.

    PubMed

    Latourette, Matthew T; Siebert, James E; Barto, Robert J; Marable, Kenneth L; Muyepa, Anthony; Hammond, Colleen A; Potchen, Michael J; Kampondeni, Samuel D; Taylor, Terrie E

    2011-08-01

    As part of an NIH-funded study of malaria pathogenesis, a magnetic resonance (MR) imaging research facility was established in Blantyre, Mala?i to enhance the clinical characterization of pediatric patients with cerebral malaria through application of neurological MR methods. The research program requires daily transmission of MR studies to Michigan State University (MSU) for clinical research interpretation and quantitative post-processing. An intercontinental satellite-based network was implemented for transmission of MR image data in Digital Imaging and Communications in Medicine (DICOM) format, research data collection, project communications, and remote systems administration. Satellite Internet service costs limited the bandwidth to symmetrical 384 kbit/s. DICOM routers deployed at both the Mala?i MRI facility and MSU manage the end-to-end encrypted compressed data transmission. Network performance between DICOM routers was measured while transmitting both mixed clinical MR studies and synthetic studies. Effective network latency averaged 715 ms. Within a mix of clinical MR studies, the average transmission time for a 256 × 256 image was ~2.25 and ~6.25 s for a 512 × 512 image. Using synthetic studies of 1,000 duplicate images, the interquartile range for 256 × 256 images was [2.30, 2.36] s and [5.94, 6.05] s for 512 × 512 images. Transmission of clinical MRI studies between the DICOM routers averaged 9.35 images per minute, representing an effective channel utilization of ~137% of the 384-kbit/s satellite service as computed using uncompressed image file sizes (including the effects of image compression, protocol overhead, channel latency, etc.). Power unreliability was the primary cause of interrupted operations in the first year, including an outage exceeding 10 days. PMID:20714916

  12. Operational Satellite-based Surface Oil Analyses (Invited)

    NASA Astrophysics Data System (ADS)

    Streett, D.; Warren, C.

    2010-12-01

    During the Deepwater Horizon spill, NOAA imagery analysts in the Satellite Analysis Branch (SAB) issued more than 300 near-real-time satellite-based oil spill analyses. These analyses were used by the oil spill response community for planning, issuing surface oil trajectories and tasking assets (e.g., oil containment booms, skimmers, overflights). SAB analysts used both Synthetic Aperture Radar (SAR) and high resolution visible/near IR multispectral satellite imagery as well as a variety of ancillary datasets. Satellite imagery used included ENVISAT ASAR (ESA), TerraSAR-X (DLR), Cosmo-Skymed (ASI), ALOS (JAXA), Radarsat (MDA), ENVISAT MERIS (ESA), SPOT (SPOT Image Corp.), Aster (NASA), MODIS (NASA), and AVHRR (NOAA). Ancillary datasets included ocean current information, wind information, location of natural oil seeps and a variety of in situ oil observations. The analyses were available as jpegs, pdfs, shapefiles and through Google, KML files and also available on a variety of websites including Geoplatform and ERMA. From the very first analysis issued just 5 hours after the rig sank through the final analysis issued in August, the complete archive is still publicly available on the NOAA/NESDIS website http://www.ssd.noaa.gov/PS/MPS/deepwater.html SAB personnel also served as the Deepwater Horizon International Disaster Charter Project Manager (at the official request of the USGS). The Project Manager’s primary responsibility was to acquire and oversee the processing and dissemination of satellite data generously donated by numerous private companies and nations in support of the oil spill response including some of the imagery described above. SAB has begun to address a number of goals that will improve our routine oil spill response as well as help assure that we are ready for the next spill of national significance. We hope to (1) secure a steady, abundant and timely stream of suitable satellite imagery even in the absence of large-scale emergencies such as Deepwater Horizon, (2) acquire a 24 x 7 oil spill response capability at least on a pre-operational basis, (3) acquire improved and expanded ancillary datasets, (4) reduce the number of false positives (analyzed oil that is not actually oil), (5) acquire the ability to reliably differentiate, at least in general qualitative terms, thick oil (“recoverable oil”) from oil sheens, and (6) join our Canadian counterparts (the Integrated Satellite Tracking of Pollution group in Environment Canada) to create a joint North American center for oil spill response.

  13. TERRESTRIAL ECOTOXICOLOGY

    EPA Science Inventory

    Terrestrial ecotoxicology is the study of how environmental pollutants affect land-dependent organisms and their environment. It requires three elements: (1) a source, (2) a receptor, and (3) an exposure pathway. This article reviews the basic principles of each of each element...

  14. Communication.

    ERIC Educational Resources Information Center

    Strauss, Andre

    The following essays on communication are presented: communication as a condition of survival, communication for special purposes, the means of transmission of communication, communication within social and economic structures, the teaching of communication through the press, the teaching of modern languages, communication as a point of departure,…

  15. Analysis of laser jamming to satellite-based detector

    Microsoft Academic Search

    Si-Wen Wang; Li-Hong Guo; Ru-Hai Guo

    2009-01-01

    The reconnaissance satellite, communication satellite and navigation satellite used in the military applications have played more and more important role in the advanced technique wars and already become the significant support and aid system for military actions. With the development of all kinds of satellites, anti-satellite laser weapons emerge as the times require. The experiments and analyses of laser disturbing

  16. IEEE Communications Surveys & Tutorials 4th Quarter 20062 he trend in designing future global communication net-

    E-print Network

    Atiquzzaman, Mohammed

    in the future global communication infra- structure [1­3]. First-generation satellite-based communica- tion these requirements, a new generation of satel- lite communications (SATCOM) networks, called broadband satelliteStar) are exam- ples of this generation of satellite communication networks [1]. These satellite communication

  17. Site-level evaluation of satellite-based global terrestrial gross primary production and net primary production

    E-print Network

    Small, Eric

    and NPP products will require site-level studies across a range of biomes, with close attention tundra site to 550 g C mÀ2 yrÀ1 at a temperate deciduous forest site. There was not a consistent over were at the temperate deciduous forest, arctic tundra, and boreal forest sites. There was moderate

  18. The OHIO Concept: Refinements on a Design for Satellite-Based Measurements of Stratospheric OH

    E-print Network

    Chance, Kelly

    The OHIO Concept: Refinements on a Design for Satellite-Based Measurements of Stratospheric OH Interferometer Observations (OHIO) concept is an option for the generalized far infrared Fabry- Perot instrument possible instrument configuration. This paper gives refined design parameters for OHIO. The design

  19. Phenology model from surface meteorology does not capture satellite-based greenup estimations

    E-print Network

    Richardson, Andrew D.

    Phenology model from surface meteorology does not capture satellite-based greenup estimations J E R used in phenology studies, but to date that has been little effort to link remotely sensed phenology to surface climate records. In this research, we use a two-parameter spring warming phenology model

  20. Influence of coherent mesoscale structures on satellite-based Doppler lidar wind measurements

    NASA Technical Reports Server (NTRS)

    Emmitt, G. D.

    1985-01-01

    The influence of coherent mesoscale structures on satellite based Doppler lidar wind measurements was investigated. Range dependent weighting functions and the single shot SNR of scan angle are examined and a space shuttle lidar experiment which used a fixed beam and rotating shuttle is simulated.

  1. Intercomparison of Rain Gauge, Radar, and Satellite-Based Precipitation Estimates with Emphasis on Hydrologic Forecasting

    Microsoft Academic Search

    Koray K. Yilmaz; Terri S. Hogue; Kuo-Lin Hsu; Soroosh Sorooshian; Hoshin V. Gupta; Thorsten Wagener

    2005-01-01

    This study compares mean areal precipitation (MAP) estimates derived from three sources: an opera- tional rain gauge network (MAPG), a radar\\/gauge multisensor product (MAPX), and the Precipitation Estimation from Remotely Sensed Information using Artificial Neural Networks (PERSIANN) satellite- based system (MAPS) for the time period from March 2000 to November 2003. The study area includes seven operational basins of varying

  2. A Satellite-based Architecture for Internet P2P Applications

    E-print Network

    Papapetrou, Evaggelos

    -aware. This results in par- tially meshed overlay networks, in which one hop breaks down to several network hopsA Satellite-based Architecture for Internet P2P Applications Evangelos Papapetrou Department satellites for building a backbone network for connecting superpeers. This network provides fully meshed

  3. Satellite-based modeling of gross primary production in an evergreen needleleaf forest

    E-print Network

    forests. The VPM model uses two improved vegetation indices (Enhanced Vegetation Index (EVI), Land SurfaceSatellite-based modeling of gross primary production in an evergreen needleleaf forest Xiangming, University of New Hampshire, Durham, NH 03833, USA b USDA Forest Service, Northeastern Research Station, 271

  4. Transport and evolution of a pollution plume from northern China: A satellite-based case study

    E-print Network

    Li, Zhanqing

    Transport and evolution of a pollution plume from northern China: A satellite-based case study Can and evolution of the plume from China to the NW Pacific on the following days. A method is proposed to combine in situ measurements and trajectory tracer modeling with satellite observations to quantify the change

  5. Satellite-based detection of Canadian boreal forest fires: development and application of the algorithm

    Microsoft Academic Search

    Z. Li; S. Nadon; J. Cihlar

    2000-01-01

    This study presents a comprehensive investigation of fires across the Canadian boreal forest zone by means of satellite-based remote sensing. A firedetection algorithm was designed to monitor fires using daily Advanced Very High Resolution Radiometer (AVHRR) images. It exploits information from multichannel AVHRR measurements to determine the locations of fires on satellite pixels of about 1 km2 under clear sky

  6. Satellite-based measurements of gravity wave-induced midlatitude plasma density

    E-print Network

    Vadas, Sharon

    and 300 km by the Dynamics Explorer-2 satellite. The wavelengths along the satellite orbit track at satellite altitudes. [3] Late in the lifetime of the DE-2 satellite its initially elliptical orbit hadSatellite-based measurements of gravity wave-induced midlatitude plasma density perturbations G. D

  7. Dynamic channel reservation in satellite-based wireless personal communication networks

    Microsoft Academic Search

    Yi Xu; Quan Long Ding; Chi Chung Ko

    2001-01-01

    This paper proposes a dynamic channel reservation scheme for an environment with changing traffic load features, such as a satellite will encounter when providing a telecommunication service at different locations. This dynamic policy makes adaptive channel reservation decisions according to the local load condition. As the suitability of channel reservation varies with traffic load, service quality of ongoing calls can

  8. Protocol Support for a New Satellite-Based Airspace Communication Network

    NASA Technical Reports Server (NTRS)

    Shang, Yadong; Hadjitheodosiou, Michael; Baras, John

    2004-01-01

    We recommend suitable transport protocols for an aeronautical network supporting Internet and data services via satellite. We study the characteristics of an aeronautical satellite hybrid network and focus on the problems that cause dramatically degraded performance of the Transport Protocol. We discuss various extensions to standard TCP that alleviate some of these performance problems. Through simulation, we identify those TCP implementations that can be expected to perform well. Based on the observation that it is difficult for an end-to-end solution to solve these problems effectively, we propose a new TCP-splitting protocol, termed Aeronautical Transport Control Protocol (AeroTCP). The main idea of this protocol is to use a fixed window for flow control and one duplicated acknowledgement (ACK) for fast recovery. Our simulation results show that AeroTCP can maintain higher utilization for the satellite link than end-to-end TCP, especially in high BER environment.

  9. Strategies for satellite-based monitoring of CO2 from distributed area and point sources

    NASA Astrophysics Data System (ADS)

    Schwandner, Florian M.; Miller, Charles E.; Duren, Riley M.; Natraj, Vijay; Eldering, Annmarie; Gunson, Michael R.; Crisp, David

    2014-05-01

    Atmospheric CO2 budgets are controlled by the strengths, as well as the spatial and temporal variabilities of CO2 sources and sinks. Natural CO2 sources and sinks are dominated by the vast areas of the oceans and the terrestrial biosphere. In contrast, anthropogenic and geogenic CO2 sources are dominated by distributed area and point sources, which may constitute as much as 70% of anthropogenic (e.g., Duren & Miller, 2012), and over 80% of geogenic emissions (Burton et al., 2013). Comprehensive assessments of CO2 budgets necessitate robust and highly accurate satellite remote sensing strategies that address the competing and often conflicting requirements for sampling over disparate space and time scales. Spatial variability: The spatial distribution of anthropogenic sources is dominated by patterns of production, storage, transport and use. In contrast, geogenic variability is almost entirely controlled by endogenic geological processes, except where surface gas permeability is modulated by soil moisture. Satellite remote sensing solutions will thus have to vary greatly in spatial coverage and resolution to address distributed area sources and point sources alike. Temporal variability: While biogenic sources are dominated by diurnal and seasonal patterns, anthropogenic sources fluctuate over a greater variety of time scales from diurnal, weekly and seasonal cycles, driven by both economic and climatic factors. Geogenic sources typically vary in time scales of days to months (geogenic sources sensu stricto are not fossil fuels but volcanoes, hydrothermal and metamorphic sources). Current ground-based monitoring networks for anthropogenic and geogenic sources record data on minute- to weekly temporal scales. Satellite remote sensing solutions would have to capture temporal variability through revisit frequency or point-and-stare strategies. Space-based remote sensing offers the potential of global coverage by a single sensor. However, no single combination of orbit and sensor provides the full range of temporal sampling needed to characterize distributed area and point source emissions. For instance, point source emission patterns will vary with source strength, wind speed and direction. Because wind speed, direction and other environmental factors change rapidly, short term variabilities should be sampled. For detailed target selection and pointing verification, important lessons have already been learned and strategies devised during JAXA's GOSAT mission (Schwandner et al, 2013). The fact that competing spatial and temporal requirements drive satellite remote sensing sampling strategies dictates a systematic, multi-factor consideration of potential solutions. Factors to consider include vista, revisit frequency, integration times, spatial resolution, and spatial coverage. No single satellite-based remote sensing solution can address this problem for all scales. It is therefore of paramount importance for the international community to develop and maintain a constellation of atmospheric CO2 monitoring satellites that complement each other in their temporal and spatial observation capabilities: Polar sun-synchronous orbits (fixed local solar time, no diurnal information) with agile pointing allow global sampling of known distributed area and point sources like megacities, power plants and volcanoes with daily to weekly temporal revisits and moderate to high spatial resolution. Extensive targeting of distributed area and point sources comes at the expense of reduced mapping or spatial coverage, and the important contextual information that comes with large-scale contiguous spatial sampling. Polar sun-synchronous orbits with push-broom swath-mapping but limited pointing agility may allow mapping of individual source plumes and their spatial variability, but will depend on fortuitous environmental conditions during the observing period. These solutions typically have longer times between revisits, limiting their ability to resolve temporal variations. Geostationary and non-sun-synchronous low-Earth-orbits (precessing loc

  10. A comprehensive design and performance analysis of LEO satellite quantum communication

    E-print Network

    Bourgoin, J -P; Higgins, B L; Helou, B; Erven, C; Huebel, H; Kumar, B; Hudson, D; D'Souza, I; Girard, R; Laflamme, R; Jennewein, T

    2012-01-01

    Optical quantum communication utilizing satellite platforms has the potential to extend the reach of quantum key distribution (QKD) from terrestrial limits of ~200 km to global scales. We have developed a thorough numerical simulation using realistic simulated orbits and incorporating the effects of pointing error, diffraction, atmosphere and telescope design, to obtain estimates of the loss and background noise which a satellite-based system would experience. Combining with quantum optics simulations of sources and detection, we determine the length of secure key for QKD, as well as entanglement visibility and achievable distances for fundamental experiments. We analyze the performance of a low Earth orbit (LEO) satellite for downlink and uplink scenarios of the quantum optical signals. We argue that the advantages of locating the quantum source on the ground justify a greater scientific interest in an uplink as compared to a downlink. An uplink with a ground transmitter of at least 25 cm diameter and a 30 c...

  11. Improving satellite-based precipitation products using data assimilation and remotely-sensed soil moisture

    Microsoft Academic Search

    W. T. Crow

    2010-01-01

    Despite their obvious relationship, relatively little attention has been paid to potential synergism between remotely-sensed surface soil moisture and precipitation products. Recent work in Crow et al. (J. Hydrometeor., 10(1), 199-212, 2009) develops an algorithm for enhancing satellite-based land rainfall products via the assimilation of remotely-sensed surface soil moisture retrievals into a land surface model. As a follow-up to this

  12. Reliable Multicast Transport by Satellite: a Hybrid Satellite/Terrestrial Solution with Erasure Codes

    E-print Network

    Mailhes, Corinne

    multipoint communication service. In the context of reliable multicast communications, a new hybrid satellite/terrestrial approach is proposed. It aims at reducing the overall communication cost using satellite broadcasting onlyReliable Multicast Transport by Satellite: a Hybrid Satellite/Terrestrial Solution with Erasure

  13. Terrestrial Ecosystem Adaptation

    E-print Network

    Mills, L. Scott

    Terrestrial Ecosystem Adaptation Steven W. Running and L. Scott Mills RFF REPORT ............................... 16 Expected Future Ecosystem Trends ................................................................................................................................................................ 27 #12; RUNNING AND MILLS 1 Terrestrial Ecosystem Adaptation Steven W. Running and L. Scott

  14. Entanglement-based quantum communication over 144km

    E-print Network

    Loss, Daniel

    , and is an essential step towards future satellite-based quantum communication and experimental tests on quantumARTICLES Entanglement-based quantum communication over 144km R. URSIN1 *, F. TIEFENBACHER1,2 , T of classical communication and computation. In view of applications such as quantum cryptography or quantum

  15. Hemispherical Snow Water Equivalent Records of Satellite-Based Data and CMIP5 Climate Model Simulations

    NASA Astrophysics Data System (ADS)

    Luojus, Kari; Pulliainen, Jouni; Takala, Matias; Lemmetyinen, Juha; Smolander, Tuomo; Ikonen, Jaakko; Cohen, Juval; Derksen, Chris

    2013-04-01

    The European Space Agency (ESA) GlobSnow project has produced a daily hemisphere-scale satellite-based snow water equivalent (SWE) data record spanning more than 30-years. The GlobSnow SWE record, based on methodology by Pulliainen [1] utilizes a data-assimilation based approach for the estimation of SWE which was shown to be superior to the approaches depending solely on satellite-based data [2]. The GlobSnow SWE data record is based on the time-series of measurements by two different space-borne passive radiometers (SMMR and SSM/I) measuring in the microwave region, spanning from 1980 to present day at a spatial resolution of approximately 25 km. We briefly present the on-going efforts taking place for further enhancement of the satellite-based SWE retrieval and the way this transfers to the reliability of the long-term SWE climate record. The development of SWE retrieval are focused on application of a new HUT multi-layer snow emission model and variational snow density scheme for SWE retrieval and efforts carried out to improve the homogeneity of the long-term record of weather station-based snow depth observations that are applied within the SWE retrieval scheme. In addition, the GlobSnow satellite-based dataset is inter-compared with climate model simulations from the CMIP5 archive. The objective of this work is to investigate the performance of the CMIP5 models in capturing the evolution of hemispheric scale snow conditions for the period of 1980 to 2010. The climate model simulations on snow cover extent, snow depth and snow water equivalent are evaluated against the GlobSnow SWE record. The goal is to assess the performance of the CMIP5 models to simulate snow conditions for the time-period that is covered by satellite-based observations. The results indicate a clear decreasing trend in total hemispherical snow mass for the period of 1980 to 2010 in the remote-sensing based data record. The inter-comparison of satellite-based record and climate model simulations show notable differences in capturing the evolution of Hemispherical scale snow conditions. Similar trends of decreasing snow cover are also seen in the investigated CMIP5 models, although there are notable differences between the various climate models. Some of the models capture the overall hemispherical snow mass more accurately than others. In general the winter months (December, January and February) seem to be rather well captured, while the spring season, (March, April and May) appears more challenging for the climate models. REFERENCES [1] Pulliainen, J. Mapping of snow water equivalent and snow depth in boreal and sub-arctic zones by assimilating space-borne microwave radiometer data and ground-based observations. Remote Sensing of Environment. 101: 257-269. DOI: 10.1016/j.rse.2006.01.002. [2] Takala, M., Luojus, K., Pulliainen, J., Derksen, C., Lemmetyinen, J., Kärnä, J.-P, Koskinen, J., Bojkov, B., "Estimating northern hemisphere snow water equivalent for climate research through assimilation of space-borne radiometer data and ground-based measurements", Remote Sensing of Environment, Vol. 115, Issue 12, 15 December 2011, Pages 3517-3529, ISSN 0034-4257, DOI: 10.1016/j.rse.2011.08.014.

  16. Uncertainties of Satellite-Based Daily Precipitation Products over the Tibetan Plateau

    NASA Astrophysics Data System (ADS)

    Shen, Yan; Chen, Zhuoqi

    2013-04-01

    Satellite-based precipitation estimates is a major way to obtain the rainfall information especially in the sparse gauged areas of the Tibetan Plateau. Based on the gauge-based precipitation analysis in summer (JJA) for the period of 2005-2007, the performance of five satellite products are examined over the Tibetan Plateau in this research including 1) the CPC MORPHing products (CMORPH) of Joyce et al. (2004); 2) MW-adjusted IR products using Artificial Neural Network (PERSIANN, Hsu et al. 1997); 3) PDF matching MW-IR products NRL (Turk et al. 2004); 4) the gauge-adjusted MW-IR merged analysis of TRMM 3B42 (Huffman et al. 2007); and 5) its real-time version TRMM 3B42RT which is a MW-IR merged product without gauge adjustments (Huffman, et al. 2004). It shows that bias does exist in all the products with the smallest bias (relative bias) of -0.252 mm/d (-8.7%) observed by TRMM/3B42. Furthermore, following the research of Tian and Peters-Lidard (2010), three data ensemble methods of algorithm mean, one-outlier-removed algorithm mean and inverse-error-square weight, respectively, are used to generate the ensemble satellite-based precipitation estimates over the Tibetan Plateau. The ensemble data produced by the inverse-error-square weight has the best performance with bias (relative bias) of -0.06mm/d (-1.9%) in summer. The uncertainty of the satellite-based precipitation products is defined as the error square between each satellite estimate and the inverse-square-error-weight ensemble data. It indicates that the uncertainty is highly dependent on the rainfall rate and increased with the rainfall rate as an exponential function. Moreover, the uncertainty is seasonal dependency with the smallest in summer and largest in winter.

  17. SETI: Search for ExtraTerrestrial Intelligence

    E-print Network

    Walter, Frederick M.

    SETI: Search for ExtraTerrestrial Intelligence I know perfectly well that at this moment the whole, The Madwoman of Chaillot #12;Search Strategies Suppose you find a civilization. You want to communicate. How? #12;Options Passive SETI: Listen Active SETI: Transmit #12;Search Strategies There are two issues: A

  18. Communications technology

    NASA Technical Reports Server (NTRS)

    Cuccia, C. Louis; Sivo, Joseph

    1986-01-01

    The technologies for optimized, i.e., state of the art, operation of satellite-based communications systems are surveyed. Features of spaceborne active repeater systems, low-noise signal amplifiers, power amplifiers, and high frequency switches are described. Design features and capabilities of various satellite antenna systems are discussed, including multiple beam, shaped reflector shaped beam, offset reflector multiple beam, and mm-wave and laser antenna systems. Attitude control systems used with the antenna systems are explored, along with multiplexers, filters, and power generation, conditioning and amplification systems. The operational significance and techniques for exploiting channel bandwidth, baseband and modulation technologies are described. Finally, interconnectivity among communications satellites by means of RF and laser links is examined, as are the roles to be played by the Space Station and future large space antenna systems.

  19. Comparison of satellite based and modelled NO2 column: Effects of spatial resolution

    NASA Astrophysics Data System (ADS)

    Chen, C.; Zhang, Q.

    2013-12-01

    Satellite based NO2 columns has been widely used in evaluating surface emissions by comparing with modeled NO2 columns with emissions data as input. In this work, we examined the effects of spatial resolution in emissions, modeled columns, and satellite based columns on the comparison. Tropospheric NO2 column densities are simulated by the CMAQ model at 36km and 12km spatial resolution with various emissions from the MEIC model (Multi-resolution Emission Inventory for China) and then compared with tropospheric NO2 columns from the Ozone Monitoring Instrument (OMI). We found that model tends to underestimate NO2 columns in urban regions under finer resolution when using population density as spatial proxy of emissions, indicating that spatial allocation approaches in bottom-up inventory have significant impacts to modeled columns in densely populated areas. Using different spatial resolutions in CMAQ model have minor impacts to the comparison. When comparing with model at 12km resolution, Spatial sampling process of satellite NO2 columns could also impact the comparison.

  20. Development of satellite-based drought monitoring and warning system in Asian Pacific countries

    NASA Astrophysics Data System (ADS)

    Takeuchi, W.; Oyoshi, K.; Muraki, Y.

    2013-12-01

    This research focuses on a development of satellite-based drought monitoring warning system in Asian Pacific countries. Drought condition of cropland is evaluated by using Keeth-Byram Drought Index (KBDI) computed from rainfall measurements with GSMaP product, land surface temperature by MTSAT product and vegetation phenology by MODIS NDVI product at daily basis. The derived information is disseminated as a system for an application of space based technology (SBT) in the implementation of the Core Agriculture Support Program. The benefit of this system are to develop satellite-based drought monitoring and early warning system (DMEWS) for Asian Pacific counties using freely available data, and to develop capacity of policy makers in those countries to apply the developed system in policy making. A series of training program has been carried out in 2013 to officers and researchers of ministry of agriculture and relevant agencies in Greater Mekong Subregion countries including Cambodia, China, Myanmar, Laos, Thailand and Vietnam. This system is running as fully operational and can be accessed at http://webgms.iis.u-tokyo.ac.jp/DMEWS/.

  1. Advances in Assimilation of Satellite-Based Passive Microwave Observations for Soil-Moisture Estimation

    NASA Technical Reports Server (NTRS)

    De Lannoy, Gabrielle J. M.; Pauwels, Valentijn; Reichle, Rolf H.; Draper, Clara; Koster, Randy; Liu, Qing

    2012-01-01

    Satellite-based microwave measurements have long shown potential to provide global information about soil moisture. The European Space Agency (ESA) Soil Moisture and Ocean Salinity (SMOS, [1]) mission as well as the future National Aeronautics and Space Administration (NASA) Soil Moisture Active and Passive (SMAP, [2]) mission measure passive microwave emission at L-band frequencies, at a relatively coarse (40 km) spatial resolution. In addition, SMAP will measure active microwave signals at a higher spatial resolution (3 km). These new L-band missions have a greater sensing depth (of -5cm) compared with past and present C- and X-band microwave sensors. ESA currently also disseminates retrievals of SMOS surface soil moisture that are derived from SMOS brightness temperature observations and ancillary data. In this research, we address two major challenges with the assimilation of recent/future satellite-based microwave measurements: (i) assimilation of soil moisture retrievals versus brightness temperatures for surface and root-zone soil moisture estimation and (ii) scale-mismatches between satellite observations, models and in situ validation data.

  2. Communications

    ERIC Educational Resources Information Center

    Bailenson, Jeremy; Buzzanell, Patrice; Deetz, Stanley; Tewksbury, David; Thompson, Robert J.; Turow, Joseph; Bichelmeyer, Barbara; Bishop, M. J.; Gayeski, Diane

    2013-01-01

    Scholars representing the field of communications were asked to identify what they considered to be the most exciting and imaginative work currently being done in their field, as well as how that work might change our understanding. The scholars included Jeremy Bailenson, Patrice Buzzanell, Stanley Deetz, David Tewksbury, Robert J. Thompson, and…

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

    E-print Network

    Gesbert, David

    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

  4. Satellite Based Education and Training in Remote Sensing and Geo-Information AN E-Learning Approach to Meet the Growing Demands in India

    NASA Astrophysics Data System (ADS)

    Raju, P. L. N.; Gupta, P. K.

    2012-07-01

    One of the prime activities of Indian Space Research Organisation's (ISRO) Space Program is providing satellite communication services, viz., television broadcasting, mobile communication, cyclone disaster warning and rescue operations etc. so as to improve their economic conditions, disseminate technical / scientific knowledge to improve the agriculture production and education for rural people of India. ISRO, along with National Aeronautical and Space Administration (NASA) conducted experimental satellite communication project i.e. Satellite Instructional Television Experiment (SITE) using NASA's Advanced Telecommunication Satellite (i.e. ATS 6) with an objective to educate poor people of India via satellite broadcasting in 1975 and 1976, covering more than 2600 villages in six states of India and territories. Over the years India built communication satellites indigenously to meet the communication requirements of India. This has further lead to launch of an exclusive satellite from ISRO for educational purposes i.e. EDUSAT in 2004 through which rich audio-video content is transmitted / received, recreating virtual classes through interactivity. Indian Institute of Remote Sensing (IIRS) established in 1966, a premier institute in south East Asia in disseminating Remote Sensing (RS) and Geographical Information System (GIS), mainly focusing on contact based programs. But expanded the scope with satellite based Distance Learning Programs for Universities, utilizing the dedicated communication satellite i.e. EDUSAT in 2007. IIRS conducted successfully eight Distance Learning Programs in the last five years and training more than 6000 students mainly at postgraduate level from more than 60 universities /Institutions spread across India. IIRS obtained feedback and improved the programs on the continuous basis. Expanded the scope of IIRS outreach program to train user departments tailor made in any of the applications of Remote Sensing and Geoinformation, capacity building for ISRO's operational projects / new satellite missions, developing e-learning contents and launching e-learning courses under twelfth five year (i.e. 2012-17) plan period of Government of India, in addition to continuing of existing distance learning programs for universities.

  5. Towards a more objective evaluation of modelled land-carbon trends using atmospheric CO2 and satellite-based vegetation activity observations

    NASA Astrophysics Data System (ADS)

    Dalmonech, D.; Zaehle, S.

    2013-06-01

    Terrestrial ecosystem models used for Earth system modelling show a significant divergence in future patterns of ecosystem processes, in particular the net land-atmosphere carbon exchanges, despite a seemingly common behaviour for the contemporary period. An in-depth evaluation of these models is hence of high importance to better understand the reasons for this disagreement. Here, we develop an extension for existing benchmarking systems by making use of the complementary information contained in the observational records of atmospheric CO2 and remotely sensed vegetation activity to provide a novel set of diagnostics of ecosystem responses to climate variability in the last 30 yr at different temporal and spatial scales. The selection of observational characteristics (traits) specifically considers the robustness of information given that the uncertainty of both data and evaluation methodology is largely unknown or difficult to quantify. Based on these considerations, we introduce a baseline benchmark - a minimum test that any model has to pass - to provide a more objective, quantitative evaluation framework. The benchmarking strategy can be used for any land surface model, either driven by observed meteorology or coupled to a climate model. We apply this framework to evaluate the offline version of the MPI Earth System Model's land surface scheme JSBACH. We demonstrate that the complementary use of atmospheric CO2 and satellite-based vegetation activity data allows pinpointing of specific model deficiencies that would not be possible by the sole use of atmospheric CO2 observations.

  6. Examining the utility of satellite-based wind sheltering estimates for lake hydrodynamic modeling

    USGS Publications Warehouse

    2014-01-01

    Satellite-based measurements of vegetation canopy structure have been in common use for the last decade but have never been used to estimate canopy's impact on wind sheltering of individual lakes. Wind sheltering is caused by slower winds in the wake of topography and shoreline obstacles (e.g. forest canopy) and influences heat loss and the flux of wind-driven mixing energy into lakes, which control lake temperatures and indirectly structure lake ecosystem processes, including carbon cycling and thermal habitat partitioning. Lakeshore wind sheltering has often been parameterized by lake surface area but such empirical relationships are only based on forested lakeshores and overlook the contributions of local land cover and terrain to wind sheltering. This study is the first to examine the utility of satellite imagery-derived broad-scale estimates of wind sheltering across a diversity of land covers. Using 30 m spatial resolution ASTER GDEM2 elevation data, the mean sheltering height, hs, being the combination of local topographic rise and canopy height above the lake surface, is calculated within 100 m-wide buffers surrounding 76,000 lakes in the U.S. state of Wisconsin. Uncertainty of GDEM2-derived hs was compared to SRTM-, high-resolution G-LiHT lidar-, and ICESat-derived estimates of hs, respective influences of land cover type and buffer width on hs are examined; and the effect of including satellite-based hs on the accuracy of a statewide lake hydrodynamic model was discussed. Though GDEM2 hs uncertainty was comparable to or better than other satellite-based measures of hs, its higher spatial resolution and broader spatial coverage allowed more lakes to be included in modeling efforts. GDEM2 was shown to offer superior utility for estimating hs compared to other satellite-derived data, but was limited by its consistent underestimation of hs, inability to detect within-buffer hs variability, and differing accuracy across land cover types. Nonetheless, considering a GDEM2 hs-derived wind sheltering potential improved the modeled lake temperature root mean square error for non-forested lakes by 0.72 °C compared to a commonly used wind sheltering model based on lake area alone. While results from this study show promise, the limitations of near-global GDEM2 data in timeliness, temporal and spatial resolution, and vertical accuracy were apparent. As hydrodynamic modeling and high-resolution topographic mapping efforts both expand, future remote sensing-derived vegetation structure data must be improved to meet wind sheltering accuracy requirements to expand our understanding of lake processes.

  7. TERRESTRIAL ECOSYSTEM SIMULATOR

    EPA Science Inventory

    The Terrestrial Habitats Project at the Western Ecology Division (Corvallis, OR) is developing tools and databases to meet the needs of Program Office clients for assessing risks to wildlife and terrestrial ecosystems. Because habitat is a dynamic condition in real-world environm...

  8. Earth and the Terrestrial

    E-print Network

    Walter, Frederick M.

    Earth and the Geology of the Terrestrial Planets (Bennett et al. Ch. 9) #12; Terrestrial planets the Sun, rotation affects erosion Crater density can indicate surface age Earth has a unique geology: ­ P-waves: compressional waves ­ S-waves: shear waves S-waves cannot pass through liquid ­ Earth

  9. Bayesian multimodel estimation of global terrestrial latent heat flux from eddy covariance, meteorological, and satellite observations

    NASA Astrophysics Data System (ADS)

    Yao, Yunjun; Liang, Shunlin; Li, Xianglan; Hong, Yang; Fisher, Joshua B.; Zhang, Nannan; Chen, Jiquan; Cheng, Jie; Zhao, Shaohua; Zhang, Xiaotong; Jiang, Bo; Sun, Liang; Jia, Kun; Wang, Kaicun; Chen, Yang; Mu, Qiaozhen; Feng, Fei

    2014-04-01

    Accurate estimation of the satellite-based global terrestrial latent heat flux (LE) at high spatial and temporal scales remains a major challenge. In this study, we introduce a Bayesian model averaging (BMA) method to improve satellite-based global terrestrial LE estimation by merging five process-based algorithms. These are the Moderate Resolution Imaging Spectroradiometer (MODIS) LE product algorithm, the revised remote-sensing-based Penman-Monteith LE algorithm, the Priestley-Taylor-based LE algorithm, the modified satellite-based Priestley-Taylor LE algorithm, and the semi-empirical Penman LE algorithm. We validated the BMA method using data for 2000-2009 and by comparison with a simple model averaging (SA) method and five process-based algorithms. Validation data were collected for 240 globally distributed eddy covariance tower sites provided by FLUXNET projects. The validation results demonstrate that the five process-based algorithms used have variable uncertainty and the BMA method enhances the daily LE estimates, with smaller root mean square errors (RMSEs) than the SA method and the individual algorithms driven by tower-specific meteorology and Modern Era Retrospective Analysis for Research and Applications (MERRA) meteorological data provided by the NASA Global Modeling and Assimilation Office (GMAO), respectively. The average RMSE for the BMA method driven by daily tower-specific meteorology decreased by more than 5 W/m2 for crop and grass sites, and by more than 6 W/m2 for forest, shrub, and savanna sites. The average coefficients of determination (R2) increased by approximately 0.05 for most sites. To test the BMA method for regional mapping, we applied it for MODIS data and GMAO-MERRA meteorology to map annual global terrestrial LE averaged over 2001-2004 for spatial resolution of 0.05°. The BMA method provides a basis for generating a long-term global terrestrial LE product for characterizing global energy, hydrological, and carbon cycles.

  10. Version 2 Goddard Satellite-Based Surface Turbulent Fluxes (GSSTF2)

    NASA Technical Reports Server (NTRS)

    Chou, Shu-Hsien; Nelkin, Eric; Ardizzone, Joe; Atlas, Robert M.; Shie, Chung-Lin; Starr, David O'C. (Technical Monitor)

    2002-01-01

    Information on the turbulent fluxes of momentum, moisture, and heat at the air-sea interface is essential in improving model simulations of climate variations and in climate studies. We have derived a 13.5-year (July 1987-December 2000) dataset of daily surface turbulent fluxes over global oceans from the Special Sensor Mcrowave/Imager (SSM/I) radiance measurements. This dataset, version 2 Goddard Satellite-based Surface Turbulent Fluxes (GSSTF2), has a spatial resolution of 1 degree x 1 degree latitude-longitude and a temporal resolution of 1 day. Turbulent fluxes are derived from the SSM/I surface winds and surface air humidity, as well as the 2-m air and sea surface temperatures (SST) of the NCEP/NCAR reanalysis, using a bulk aerodynamic algorithm based on the surface layer similarity theory.

  11. Model-based monitoring and diagnosis of a satellite-based instrument

    NASA Technical Reports Server (NTRS)

    Bos, Andre; Callies, Jorg; Lefebvre, Alain

    1995-01-01

    For about a decade model-based reasoning has been propounded by a number of researchers. Maybe one of the most convincing arguments in favor of this kind of reasoning has been given by Davis in his paper on diagnosis from first principles (Davis 1984). Following their guidelines we have developed a system to verify the behavior of a satellite-based instrument GOME (which will be measuring Ozone concentrations in the near future (1995)). We start by giving a description of model-based monitoring. Besides recognizing that something is wrong, we also like to find the cause for misbehaving automatically. Therefore, we show how the monitoring technique can be extended to model-based diagnosis.

  12. Inter-comparison of spatial upscaling methods for evaluation of satellite-based soil moisture

    NASA Astrophysics Data System (ADS)

    Qin, Jun; Zhao, Long; Chen, Yingying; Yang, Kun; Yang, Yaping; Chen, Zhuoqi; Lu, Hui

    2015-04-01

    Soil moisture is a key factor in energy and water cycles. Many satellite missions have been planned and implemented for retrieving soil moisture globally. Because the spatial representativeness of a point-scale soil moisture station is rather limited, a station network needs setting up for scale-matching validation of satellite-based soil moisture products. Even so, an upscaling procedure is needed to upscale these station soil moisture values into area-wide one. However, such a procedure itself introduces uncertainties into the upscaled soil moisture. In this study, four upscaling methods (simple average, block kriging, model-based, and apparent-thermal-inertia-based) are inter-compared according to their performance stability for evaluation of soil moisture estimated by assimilating microwave signals into a land surface model. It is found that the performance of the model-based upscaling approach is the most unstable because model simulations are full of uncertainties for representing spatial variability of soil moisture. The block kriging upscaling method performs not worse than the simple averaging approach; the former may generate more representative soil moisture if the range of the soil moisture semivariogram used in the block kriging is comparable to the extent of a satellite footprint. The apparent-thermal-inertia-based upscaling is the most stable one, which has been developed with the aid of high-resolution satellite thermal data. All analyses indicate that choosing a suitable upscaling approach is important for the effective evaluation of satellite-based soil moisture. Otherwise, uncertainties hiding in the upscaling method will be incorrectly attributed to errors in satellite products, undermining our confidence in implementing them into practice.

  13. Solar Irradiance Variability: Validation of Satellite-Based Assessment and Prospective Enhancements

    NASA Astrophysics Data System (ADS)

    Nonnenmacher, L.; Coimbra, C.

    2013-12-01

    Based on the technological advances and recent growth rates in deployment, solar energy will contribute significantly in the prospective global energy system. However, the intermittent output characteristics of solar energy systems pose a major challenge for the integration of this renewable power resource into the existing power grid. The intra-day solar variability causing output ramps is primarily caused by clouds and aerosols interacting with solar radiation passing through the atmosphere. Recent advances proposed different methods to assess and quantify irradiance fluctuations at the earth's surface. While remote sensing models based on satellite imagery can provide variability data for a vast domain, the temporal resolution is low and show a dearth of validation. In contrast to that, the spatial resolution of ground based instrumentation is limited whereas temporal resolution, precision and accuracy is high. Our validation of satellite based assessment of solar variability with ground truth measurements shows that the satellite based methods provide an accurate picture of variability with half hourly temporal resolution. However, half hourly variability values disregard a large portion of amplitude and frequency of solar variability on shorter timescales. This contribution seeks to investigate the characteristics of different measures of solar irradiance variability, evaluates the accuracy of common variability assessment techniques and finally proposes methods to estimate solar variability in different microclimates under different atmospheric conditions with improved accuracy. Our work shows a novel hybrid approach based on a combination of satellite and sky imager observations to scale down variability values from a 30 minute resolution to a significantly shorter timescale. Current research investigates the applicability and universality of a scaling-law with multiple inputs to derive temporal variability characteristics.

  14. Current trends in satellite based emergency mapping - the need for harmonisation

    NASA Astrophysics Data System (ADS)

    Voigt, Stefan

    2013-04-01

    During the past years, the availability and use of satellite image data to support disaster management and humanitarian relief organisations has largely increased. The automation and data processing techniques are greatly improving as well as the capacity in accessing and processing satellite imagery in getting better globally. More and more global activities via the internet and through global organisations like the United Nations or the International Charter Space and Major Disaster engage in the topic, while at the same time, more and more national or local centres engage rapid mapping operations and activities. In order to make even more effective use of this very positive increase of capacity, for the sake of operational provision of analysis results, for fast validation of satellite derived damage assessments, for better cooperation in the joint inter agency generation of rapid mapping products and for general scientific use, rapid mapping results in general need to be better harmonized, if not even standardized. In this presentation, experiences from various years of rapid mapping gained by the DLR Center for satellite based Crisis Information (ZKI) within the context of the national activities, the International Charter Space and Major Disasters, GMES/Copernicus etc. are reported. Furthermore, an overview on how automation, quality assurance and optimization can be achieved through standard operation procedures within a rapid mapping workflow is given. Building on this long term rapid mapping experience, and building on the DLR initiative to set in pace an "International Working Group on Satellite Based Emergency Mapping" current trends in rapid mapping are discussed and thoughts on how the sharing of rapid mapping information can be optimized by harmonizing analysis results and data structures are presented. Such an harmonization of analysis procedures, nomenclatures and representations of data as well as meta data are the basis to better cooperate within the global rapid mapping community throughout local/national, regional/supranational and global scales

  15. Estimation of volcanic eruption characteristics using satellite-based observations and coherent trajectory ensembles

    NASA Astrophysics Data System (ADS)

    Seidenberger, K.; Erbertseder, T.; Maerker, C.; Valks, P.; Rix, M.

    2009-04-01

    Volcanic eruptions and unrest are among the main natural hazards, which influence nature, human beings and climate. Large amounts of ash, rock fragments and trace gases can be emitted into the atmosphere. One of these trace gases is sulphur dioxide (SO2) which is a good indicator for volcanic ash clouds and can be detected by several satellite instruments such as GOME-2 (Global Ozone Monitoring Experiment) and OMI (Ozone Monitoring Instrument). These satellite-based observations provide a global and daily monitoring of total SO2 columns of volcanic or anthropogenic origin. However, the measurements only deliver a two-dimensional snapshot of the SO2 distribution i.e. SO2 plumes. By combining satellite observations of increased SO2 concentrations and a newly developed backward trajectory ensemble modelling technique, information on volcanic eruption characteristics and SO2 plumes can be derived. Relevant parameters such as the location of the emission source, the moment of the eruption as well as the emission or plume height are estimated from the observations. The method uses geolocations and observation times of enhanced SO2 values from satellite-based measurements, meteorological analyses from the European Centre for Medium Range Weather Forecast (ECMWF) and the Lagrangian kinematic trajectory model FLEXTRA. The sensitivity of the retrieved parameters versus the initialisation parameters of the inversion (observation time, longitude and latitude) was tested for significance. Different case studies for recent volcanic eruptions are presented: (1) the eruption of Mount Etna, Italy in May 2008, (2) Hawaiian effusive eruptions in 2008 and (3) the eruption of Mount Okmok, Alaska in July 2008. In order to evaluate the presented method the derived source terms were used to initialize forward integrations of the 3D Eulerian chemical transport model POLYPHEMUS and the 3D Lagrangian particle dispersion model FLEXPART. The resulting SO2 plumes were finally compared to observations.

  16. Comparison of global precipitation climatology products derived from ground- and satellite-based measurements

    NASA Astrophysics Data System (ADS)

    Liu, Zhong

    2014-11-01

    Satellite-based products increasingly take an important role in filling data gaps in data sparse regions around the world. In recent years, precipitation products that utilize multi-satellite and multi-sensor datasets have been gaining more popularity than products from a single sensor or satellite. Adjusted with gauge and ground radar data, satellitebased products have been significantly improved. However the history of satellite-based precipitation products is relatively short compared to the length of 30 years in the definition for climatology from the World Meteorological Organization (WMO). For example, the NASA/JAXA Tropical Rainfall Measuring Mission (TRMM) has been in operation for over 16 years since 1997. The length of TRMM is far shorter than those from ground observations, raising a question whether TRMM climatology products are good enough for research and applications. In this study, three climatologies derived from ground observations (Global Precipitation Climatology Centre (GPCC) and Willmott and Matsuura (WM)) and a blended product (the TRMM Multi-Satellite Precipitation Analysis (TMPA) monthly product or 3B43) are compared on a global scale to assess the performance and weaknesses of the TMPAderived climatology. Results show that the 3B43 climatology matches well with the two gauge-based climatologies in all seasons in terms of spatial distribution, zonal means as well as seasonal variations. However, high variations in rain rates are found in light rain regions such as the Sahara Desert. Large negative biases (3B43

  17. Comparison of machine learning algorithms for their applicability in satellite-based optical rainfall retrievals

    NASA Astrophysics Data System (ADS)

    Meyer, Hanna; Kühnlein, Meike; Appelhans, Tim; Nauss, Thomas

    2015-04-01

    Machine learning (ML) algorithms have been successfully evaluated as valuable tools in satellite-based rainfall retrievals which shows the high potential of ML algorithms when faced with high dimensional and complex data. Moreover, the recent developments in parallel computing with ML offer new possibilities in terms of training and predicting speed and therefore makes their usage in real time systems feasible. The present study compares four ML algorithms for rainfall area detection and rainfall rate assignment during daytime, night-time and twilight using MSG SEVIRI data over Germany. Satellite-based proxies for cloud top height, cloud top temperature, cloud phase and cloud water path are applied as predictor variables. As machine learning algorithms, random forests (RF), neural networks (NNET), averaged neural networks (AVNNET) and support vector machines (SVM) are chosen. The comparison is realised in three steps. First, an extensive tuning study is carried out to customise each of the models. Secondly, the models are trained using the optimum values of model parameters found in the tuning study. Finally, the trained models are used to detect rainfall areas and to assign rainfall rates using an independent validation datasets which is compared against ground-based radar data. To train and validate the models, the radar-based RADOLAN RW product from the German Weather Service (DWD) is used which provides area-wide gauge-adjusted hourly precipitation information. Though the differences in the performance of the algorithms were rather small, NNET and AVNNET have been identified as the most suitable algorithms. On average, they showed the best performance in rainfall area delineation as well as in rainfall rate assignment. The fast computation time of NNET allows to work with large datasets as it is required in remote sensing based rainfall retrievals. However, since none of the algorithms performed considerably better that the others we conclude that research effort is needed in providing suitable predictors for rainfall rather than in optimizing by the choice of the ML algorithm.

  18. Information and communication technology in disease surveillance, India: a case study

    PubMed Central

    2010-01-01

    India has made appreciable progress and continues to demonstrate a strong commitment for establishing and operating a disease surveillance programme responsive to the requirements of the International Health Regulations (IHR[2005]). Within five years of its launch, India has effectively used modern information and communication technology for collection, storage, transmission and management of data related to disease surveillance and effective response. Terrestrial and/or satellite based linkages are being established within all states, districts, state-run medical colleges, infectious disease hospitals, and public health laboratories. This network enables speedy data transfer, video conferencing, training and e-learning for outbreaks and programme monitoring. A 24x7 call centre is in operation to receive disease alerts. To complement these efforts, a media scanning and verification cell functions to receive reports of early warning signals. During the 2009 H1N1 outbreak, the usefulness of the information and communication technology (ICT) network was well appreciated. India is using ICT as part of its Integrated Disease Surveillance Project (IDSP) to help overcome the challenges in further expansion in hard-to-reach populations, to increase the involvement of the private sector, and to increase the use of other modes of communication like e-mail and voicemail. PMID:21143821

  19. Satellite-based estimation of surface vapor pressure deficits using MODIS land surface temperature data

    Microsoft Academic Search

    Hirofumi Hashimoto; Jennifer L. Dungan; Michael A. White; Feihua Yang; Andrew R. Michaelis; Steven W. Running; Ramakrishna R. Nemani

    2008-01-01

    Vapor Pressure Deficit (VPD) is a principle mediator of global terrestrial CO2 uptake and water vapor loss through plant stomata. As such, methods to estimate VPD accurately and efficiently are critical for ecosystem and climate modeling efforts. Based on prior work relating energy partitioning, remotely sensed land surface temperature (LST), and VPD, we developed simple linear models to predict VPD

  20. A new generation of satellite based solar irradiance calculation schemes R. W. Mueller, D. Heinemann, C. Hoyer & R. Kuhlemann

    E-print Network

    Heinemann, Detlev

    A new generation of satellite based solar irradiance calculation schemes R. W. Mueller, D ABSTRACT: A successful integration of solar energy into the existing energy structure highly depends of the enhanced capabilities of the new Meteosat Second Generation (MSG) satellites. The expected quality

  1. Satellite-Based Distance Courses for In-Service Training: The Case of HeadsUp! Reading

    ERIC Educational Resources Information Center

    Morrison, Johnetta Wade; Raya-Carlton, Pamela; Henk, Jennifer K.; Thornburg, Kathy R.

    2007-01-01

    This article discusses the use of distance courses as an in-service training mechanism for early childhood personnel. The authors evaluated the efficacy of the in-service, satellite based distance course HeadsUp! Reading (HU!R). The analysis of HU!R data revealed that there were no initial differences in the Language and Literacy Early Childhood:…

  2. Correcting rainfall using satellite-based surfae soil moisture retrievals: The soil moisture analysis rainfall tool(SMART)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent work in Crow et al. (2009) developed an algorithm for enhancing satellite-based land rainfall products via the assimilation of remotely-sensed surface soil moisture retrievals into a water balance model. As a follow-up, this paper describes the benefits of modifying their approach to incorpor...

  3. Evaluation of a Moderate Resolution, Satellite-Based Impervious Surface Map Using an Independent, High-Resolution Validation Dataset

    EPA Science Inventory

    Given the relatively high cost of mapping impervious surfaces at regional scales, substantial effort is being expended in the development of moderate-resolution, satellite-based methods for estimating impervious surface area (ISA). To rigorously assess the accuracy of these data ...

  4. Mesoscale variability in time series data: Satellite-based estimates for the U.S. JGOFS Bermuda Atlantic

    E-print Network

    Mesoscale variability in time series data: Satellite-based estimates for the U.S. JGOFS Bermuda TOPEX/Poseidon­ERS-1/2) are used to characterize, statistically, the mesoscale variability about the U to better understand the contribution of mesoscale eddies to the time series record and the model- data

  5. Robotic in-situ and satellite based observations of pigment and particle distributions in the Western North Atlantic

    E-print Network

    - 1 - Robotic in-situ and satellite based observations of pigment and particle distributions patterns associated with phytoplankton blooms as well as increase in pigmentation per particle at low light was associated with a weakly elevated pigment and backscattering at the surface but its depth integrated

  6. Satellite-based evidence of wavelength-dependent aerosol absorption in biomass burning smoke inferred from ozone monitoring instrument

    Microsoft Academic Search

    H. Jethva; O. Torres

    2011-01-01

    We provide satellite-based evidence of the spectral dependence of absorption in biomass burning aerosols over South America using near-UV measurements made by Ozone Monitoring Instrument (OMI) during 2005-2007. Currently, OMAERUV aerosol algorithm characterizes carbonaceous aerosol as \\

  7. Evolution of Terrestrial Atmospheres

    NSDL National Science Digital Library

    O'Connell, Robert W.

    This lecture compares terrestrial atmospheres as well as discusses atmospheric processes, atmospheric equilibrium, and the atmospheric development of Mars, Venus, and Earth. It ends with a discussion of natural and unnatural climatic changes.

  8. Terrestrial Impact Structures

    NASA Astrophysics Data System (ADS)

    Grieve, R. A. F.

    Emphasis is placed on the nature of terrestrial impact structures, the criteria for their identification, and their contribution to constraining formational processes and cratering rate estimates. The relationship of large-scale impact to Earth history is also considered.

  9. 22nd AIAA International Communications Satellite Systems Conference & Exhibit 2004 9 -12 May 2004, Monterey, California

    E-print Network

    Baras, John S.

    22nd AIAA International Communications Satellite Systems Conference & Exhibit 2004 9 -12 May 2004 of satellite technology for aeronautical communications, the airline industry is developing a design for a global satellite-based communications system to meet the needs of the aviation industry [2]. Copyright

  10. Are satellite based rainfall estimates accurate enough for crop modelling under Sahelian climate?

    NASA Astrophysics Data System (ADS)

    Ramarohetra, J.; Sultan, B.

    2012-04-01

    Agriculture is considered as the most climate dependant human activity. In West Africa and especially in the sudano-sahelian zone, rain-fed agriculture - that represents 93% of cultivated areas and is the means of support of 70% of the active population - is highly vulnerable to precipitation variability. To better understand and anticipate climate impacts on agriculture, crop models - that estimate crop yield from climate information (e.g rainfall, temperature, insolation, humidity) - have been developed. These crop models are useful (i) in ex ante analysis to quantify the impact of different strategies implementation - crop management (e.g. choice of varieties, sowing date), crop insurance or medium-range weather forecast - on yields, (ii) for early warning systems and to (iii) assess future food security. Yet, the successful application of these models depends on the accuracy of their climatic drivers. In the sudano-sahelian zone , the quality of precipitation estimations is then a key factor to understand and anticipate climate impacts on agriculture via crop modelling and yield estimations. Different kinds of precipitation estimations can be used. Ground measurements have long-time series but an insufficient network density, a large proportion of missing values, delay in reporting time, and they have limited availability. An answer to these shortcomings may lie in the field of remote sensing that provides satellite-based precipitation estimations. However, satellite-based rainfall estimates (SRFE) are not a direct measurement but rather an estimation of precipitation. Used as an input for crop models, it determines the performance of the simulated yield, hence SRFE require validation. The SARRAH crop model is used to model three different varieties of pearl millet (HKP, MTDO, Souna3) in a square degree centred on 13.5°N and 2.5°E, in Niger. Eight satellite-based rainfall daily products (PERSIANN, CMORPH, TRMM 3b42-RT, GSMAP MKV+, GPCP, TRMM 3b42v6, RFEv2 and EPSAT-SG) are integrated using a crop model, then compared and tested against simulations obtained using in situ data. As in situ data, kriged rain gauge measurements are computed from about 50 rain gauges within the square degree. We show that direct use of SRFE does not reproduce the yield variability obtained from in situ observations. In a second time, different satellite products errors (e.g. annual bias, accuracy at the beginning of the rainy season) are corrected before yield modelling to assess their impact on crop yield simulation and to be able to know which improvement in SRFE will be useful for crop yield estimation. We show that corrected satellite products enable a better yield variability representation and that error correction does not have the same impact on the different varieties computed. Finally, simulated yield quality versus precipitations temporal resolution is assessed - as well as SRFE accuracy versus SRFE temporal resolution - in order to sort out the best agreement between temporal resolution and SRFE accuracy.

  11. Extra Terrestrial Lava Flows

    NASA Technical Reports Server (NTRS)

    Lopes-Gautier, R.

    1993-01-01

    Volcanism has been one of the major processes shaping the surfaces of the terrestrial planets. Lava flows have been identified on the Moon, Mars, Venus, and on Juptier's moon Io. The study of extra-terrestrial lavas has largely relied on the interpretation of remotely acquired imaging, topographic and spectroscopic data. Models relating the final flow morpohology to eruption characteristics and magma chemistry have been important tools in the interpretation of these data.

  12. Efficient all solid-state UV source for satellite-based lidar applications.

    SciTech Connect

    Armstrong, Darrell Jewell; Smith, Arlee Virgil

    2003-07-01

    A satellite-based UV-DIAL measurement system would allow continuous global monitoring of ozone concentration in the upper atmosphere. However such systems remain difficult to implement because aerosol-scattering return signals for satellite-based lidars are very weak. A suitable system must produce high-energy UV pulses at multiple wavelengths with very high efficiency. For example, a nanosecond system operating at 10 Hz must generate approximately 1 J per pulse at 308-320 nm. An efficient space-qualified wavelength-agile system based on a single UV source that can meet this requirement is probably not available using current laser technology. As an alternative, we're pursuing a multi-source approach employing all-solid-state modules that individually generate 300-320 nm light with pulse energies in the range of 50-200 mJ, with transform-limited bandwidths and good beam quality. Pulses from the individual sources can be incoherently summed to obtain the required single-pulse energy. These sources use sum-frequency mixing of the 532 nm second harmonic of an Nd:YAG pump laser with 731-803 nm light derived from a recently-developed, state-of-the-art, nanosecond optical parametric oscillator. Two source configurations are under development, one using extra-cavity sum-frequency mixing, and the other intra-cavity sum-frequency mixing. In either configuration, we hope to obtain sum-frequency mixing efficiency approaching 60% by carefully matching the spatial and temporal properties of the laser and OPO pulses. This ideal balance of green and near-IR photons requires an injection-seeded Nd:YAG pump-laser with very high beam quality, and an OPO exhibiting unusually high conversion efficiency and exceptional signal beam quality. The OPO employs a singly-resonant high-Fresnel-number image-rotating self-injection-seeded nonplanar-ring cavity that achieves pump depletion > 65% and produces signal beams with M{sup 2} {approx} 3 at pulse energies exceeding 50 mJ. Pump beam requirements can be met in the laboratory using a commercial Nd:YAG laser system, but only after extensive modifications.

  13. Multitemporal Monitoring of the Air Quality in Bulgaria by Satellite Based Instruments

    NASA Astrophysics Data System (ADS)

    Nikolov, Hristo; Borisova, Denitsa

    2015-04-01

    Nowadays the effect on climate changes on the population and environment caused by air pollutants at local and regional scale by pollution concentrations higher than allowed is undisputable. Main sources of gas releases are due to anthropogenic emissions caused by the economic and domestic activities of the inhabitants, and to less extent having natural origin. Complementary to pollutants emissions the local weather parameters such as temperature, precipitation, wind speed, clouds, atmospheric water vapor, and wind direction control the chemical reactions in the atmosphere. It should be noted that intrinsic property of the air pollution is its "transboundary-ness" and this is why the air quality (AQ) is not affecting the population of one single country only. This why the exchange of information concerning AQ at EU level is subject to well established legislation and one of EU flagship initiatives for standardization in data exchange, namely INSPIRE, has to cope with. It should be noted that although good reporting mechanism with regard to AQ is already established between EU member states national networks suffer from a serious disadvantage - they don't form a regular grid which is a prerequisite for verification of pollutants transport modeling. Alternative sources of information for AQ are the satellite observations (i.e. OMI, TOMS instruments) providing daily data for ones of the major contributors to air pollution such as O3, NOX and SO2. Those data form regular grids and are processed the same day of the acquisition so they could be used in verification of the outputs generated by numerical modeling of the AQ and pollution transfer. In this research we present results on multitemporal monitoring of several regional "hot spots" responsible for greenhouse gases emissions in Bulgaria with emphasis on satellite-based instruments. Other output from this study is a method for validation of the AQ forecasts and also providing feedback to the service that prepares them. The following sources of in-situ data for the different types of gases and dust particles have been used - the National Institute of Meteorology and Hydrology of Bulgaria (NIMH) and National System for Environmental Monitoring managed by Bulgarian Executive Environmental Agency (ExEA). Both authorities provide data for concentration of several gases just to mention CO, CO2, NO2, SO2, and fine suspended dust (PM10, PM2.5) on monthly (for some data on daily) basis. Considered satellite-based instruments for data provision are OMI instrument aboard EOS-Aura satellite and from TROPOMI instrument which is basic payload for the future Sentinel-5P mission.

  14. Weather Information Communications (WINCOMM) Overview and Status

    NASA Technical Reports Server (NTRS)

    Martzaklis, K.

    2003-01-01

    The second annual project review of Weather Information Communications (WINCOMM) is presented. The topics of discussion include: 1) In-Flight Weather Information; 2) System Elements; 3) Technology Investment Areas; 4) NAS Information Exchange; 5) FIS Datalink Architecture Analyses; 6) Hybrid FIS Datalink Architecture; 7) FIS Datalink Architecture Analyses; 8) Air Transport: Ground and Satellite-based Datalinks; 9) General Aviation: Ground and Satellite-based Datalinks; 10) Low Altitude AutoMET Reporting; 11) AutoMET: Airborne-based Datalinks; 12) Network Protocols Development; and 13) FAA/NASA Collaboration. A summary of WINCOMM is also included. This paper is in viewgraph form.

  15. Validation of precipitation retrievals over land from satellite-based passive microwave sensors

    NASA Astrophysics Data System (ADS)

    Tang, Ling; Tian, Yudong; Lin, Xin

    2014-04-01

    Precipitation retrievals from spaceborne passive microwave (PMW) radiometers are the backbone of modern satellite-based global precipitation data sets. The error characteristics in these individual retrievals directly affect the merged end products and applications but have not been systematically studied. This paper focuses on extensive and systematic validation of PMW precipitation retrievals and quantification of their error characteristics. Retrievals from 12 PMW radiometers were evaluated and intercompared at instantaneous scale (5 min) over continental United States. These precipitation-sensing radiometers include both imagers (Tropical Rainfall Measuring Mission Microwave Imager, Advanced Microwave Scanning Radiometer for the Earth Observing System, Special Sensor Microwave Imager, and Special Sensor Microwave Imager/Sounder) and sounders (advanced microwave sounding unit-B and Microwave Humidity Sounders). A high-resolution ground radar-based data set over the continental United States was used as the ground reference data. The high spatial and temporal resolution of the reference data allows collocation within 5 min and relatively more precise comparison with the satellite overpasses. Our results show that PMW sensor retrievals exhibit fairly systematic biases depending on season and precipitation intensity, with overestimates in summer at moderate to high precipitation rates and underestimates in winter at low and moderate precipitation rates. Retrievals from the microwave imagers have notably better performance than those from the sounders. The latter tend to have a narrower dynamic range, higher biases, and random errors.

  16. Comparing in situ and satellite-based parameterizations of oceanic whitecaps

    NASA Astrophysics Data System (ADS)

    Paget, Aaron C.; Bourassa, Mark A.; Anguelova, Magdalena D.

    2015-04-01

    The majority of the parameterizations developed to estimate whitecap fraction uses a stability-dependent 10 m wind (U10) measured in situ, but recent efforts to use satellite-reported equivalent neutral winds (U10EN) to estimate whitecap fraction with the same parameterizations introduce additional error. This study identifies and quantifies the differences in whitecap parameterizations caused by U10 and U10EN for the active and total whitecap fractions. New power law coefficients are presented for both U10 and U10EN parameterizations based on available in situ whitecap observations. One-way analysis of variance (ANOVA) tests are performed on the residuals of the whitecap parameterizations and the whitecap observations and identify that parameterizations in terms of U10 and U10EN perform similarly. The parameterizations are also tested against the satellite-based WindSat Whitecap Database to assess differences. The improved understanding aids in estimating whitecap fraction globally using satellite products and in determining the global effects of whitecaps on air-sea processes and remote sensing of the surface.

  17. A Satellite Based Modeling Framework for Estimating Seasonal Carbon Fluxes Over Agricultural Lands

    NASA Astrophysics Data System (ADS)

    Bandaru, V.; Izaurralde, R. C.; Sahajpal, R.; Houborg, R.; Milla, Z.

    2013-12-01

    Croplands are typically characterized by fine-scale heterogeneity, which makes it difficult to accurately estimate cropland carbon fluxes over large regions given the fairly coarse spatial resolution of high-frequency satellite observations. It is, however, important that we improve our ability to estimate spatially and temporally resolved carbon fluxes because croplands constitute a large land area and have a large impact on global carbon cycle. A Satellite based Dynamic Cropland Carbon (SDCC) modeling framework was developed to estimate spatially resolved crop specific daily carbon fluxes over large regions. This modeling framework uses the REGularized canopy reFLECtance (REGFLEC) model to estimate crop specific leaf area index (LAI) using downscaled MODIS reflectance data, and subsequently LAI estimates are integrated into the Environmental Policy Integrated Model (EPIC) model to determine daily net primary productivity (NPP) and net ecosystem productivity (NEP). Firstly, we evaluate the performance of this modeling framework over three eddy covariance flux tower sites (Bondville, IL; Fermi Agricultural Site, IL; and Rosemount site, MN). Daily NPP and NEP of corn and soybean crops are estimated (based on REGFLEC LAI) for year 2007 and 2008 over the flux tower sites and compared against flux tower observations and model estimates based on in-situ LAI. Secondly, we apply the SDCC framework for estimating regional NPP and NEP for corn, soybean and sorghum crops in Nebraska during year 2007 and 2008. The methods and results will be presented.

  18. Development concerns for satellite-based air traffic control surveillance systems

    NASA Technical Reports Server (NTRS)

    Mcdonald, K. D.

    1985-01-01

    Preliminary results of an investigation directed toward the configuration of a practical system design which can form the baseline for assessing the applications and value of a satellite based air traffic surveillance system for future use in the National Airspace System (NAS) are described. This work initially studied the characteristics and capabilities of a satellite configuration which would operate compatibly with the signal structure and avionics of the next generation air traffic control secondary surveillance radar system, the Mode S system. A compatible satellite surveillance system concept is described and an analysis is presented of the link budgets for the various transmission paths. From this, the satellite characteristics are established involving a large multiple feed L band antenna of approximately 50 meter aperture dimension. Trade offs involved in several of the alternative large aperture antennas considered are presented as well as the influence of various antenna configurations on the performance capabilities of the surveillance system. The features and limitations of the use of large aperture antenna systems for air traffic surveillance are discussed. Tentative results of this continuing effort are summarized with a brief description of follow on investigations involving other space based antenna systems concepts.

  19. A Satellite Based Modeling Framework for Estimating Seasonal Carbon Fluxes Over Agricultural Lands

    NASA Astrophysics Data System (ADS)

    Bandaru, V.; Houborg, R.; Izaurralde, R. C.

    2014-12-01

    Croplands are typically characterized by fine-scale heterogeneity, which makes it difficult to accurately estimate cropland carbon fluxes over large regions given the fairly coarse spatial resolution of high-frequency satellite observations. It is, however, important that we improve our ability to estimate spatially and temporally resolved carbon fluxes because croplands constitute a large land area and have a large impact on global carbon cycle. A Satellite based Dynamic Cropland Carbon (SDCC) modeling framework was developed to estimate spatially resolved crop specific daily carbon fluxes over large regions. This modeling framework uses the REGularized canopy reFLECtance (REGFLEC) model to estimate crop specific leaf area index (LAI) using downscaled MODIS reflectance data, and subsequently LAI estimates are integrated into the Environmental Policy Integrated Model (EPIC) model to determine daily net primary productivity (NPP) and net ecosystem productivity (NEP). Firstly, we evaluate the performance of this modeling framework over three eddy covariance flux tower sites (Bondville, IL; Fermi Agricultural Site, IL; and Rosemount site, MN). Daily NPP and NEP of corn and soybean crops are estimated (based on REGFLEC LAI) for year 2007 and 2008 over the flux tower sites and compared against flux tower observations and model estimates based on in-situ LAI. Secondly, we apply the SDCC framework for estimating regional NPP and NEP for corn, soybean and sorghum crops in Nebraska during year 2007 and 2008. The methods and results will be presented.

  20. Influence of Satellite-Based Heterogeneous Vegetation Momentum Roughness on Mesoscale Model Dynamics During IHOP 2002

    NASA Technical Reports Server (NTRS)

    Jasinski, Michael; Eastman, Joseph; Borak, Jordan

    2010-01-01

    The sensitivity of mesoscale weather prediction model to a vegetation roughness initialization is investigated for the south central United States. Three different roughness databases are employed: i) a control or standard lookup table roughness that is a function only of land cover type, ii) a spatially heterogeneous roughness database previously derived using a physically based procedure and MODIS imagery, and iii) a MODIS climatologic roughness database that possesses the same spatial heterogeneity as (i) but with mean land class values from (ii). The model used is the Weather Research and Forecast Model (WRF) coupled to the Community Land Model within the Land Information System (LIS). For each simulation, a statistical comparison is made between modeled results and ground observations from meteorological stations within the Oklahoma mesonet and surrounding region during IHOP20O2. A sensitivity analysis on the impact the MODIS-based roughness fields is also made through a time-series intercomparison of temperature bias, probability of detection (POD), average wind speed, boundary layer height, and turbulent kinetic energy (TKE) the results that, for the current replacement of the standard land-cover type based roughness values with the satellite-derived fields statistically improves model performance for most of the observed variables. Further, the satellite-based roughness enhances the surface wind speed, PBL height and TKE production on the order of 3 to l0 percent, with a lesser effect over grassland and cropland domains, and the greater effect over mixed land cover domains

  1. New satellite-based maps of the growing season north of 50°N

    NASA Astrophysics Data System (ADS)

    Rune Karlsen, Stein; Arild Høgda, Kjell; Tolvanen, Anne; Johansen, Bernt; Elvebakk, Arve

    2010-11-01

    In this study we present new satellite-based maps of the growing season of northern areas. The maps show trends and mean date in onset and length of the growing season at different scales north of 50° N. For all the circumpolar area we use the GIMMS-NDVI satellite dataset for the 1982 to 2006 period, and for the Nordic countries we used the MODISNDVI satellite data for the 2000 to 2007 period. The circumpolar maps are not as accurate as the one covering the Nordic countries, this due to lack of ancillary environmental geo-data available that can be included in the mapping process. In particular this is a problem for the Russian part of the circumpolar north. The resulting growing season maps are useful in a broad range of ecological and climatic changes studies. Changes in the timing of the growing season are sensitive bio-indicators of climate change of northern areas, and these changes crucially affects primary industries, such as agriculture, animal husbandry and forestry, as well as the population dynamics of wild mammals and birds. The onset of growing season maps is also useful to improve pollen forecasts, and the maps can be used to improve the global change models.

  2. A Fast Radiative Transfer Model for the Meteor- M satellite-based hyperspectral IR sounders

    NASA Astrophysics Data System (ADS)

    Uspensky, A. B.; Rublev, A. N.; Rusin, E. V.; Pyatkin, V. P.

    2014-12-01

    The methodological and computational aspects of Fast Radiative Transfer Model (FRTM) development designed for the analysis and validation of the data of measurements using satellite-based instrument-hyperspectral IR sounders of high spectral resolution—are considered. A description of the FRTM is given for the analysis and modeling of the measurements by the IRFS-2 IR Fourier spectrometer for polarorbiting meteorological satellites of the Meteor-M series based on the known RTTOV FRTM. Computational efficiency is estimated and the results of the verification of developed FRTM are presented. They were obtained from a comparison of model simulations with exact line-by-line calculations for the IRFS-2 IR sounder. The increase in computational performance and the accuracy of the FRTM, caused by the application of the algorithms of the principal components method, are discussed. The construction of radiative models, which use the algorithm of the Monte Carlo method and are applicable for the analysis and modeling of the data of IR sounders under conditions of cloudiness in the instrument field of view, is considered.

  3. GWD-LR: a satellite-based global database of river channel width

    NASA Astrophysics Data System (ADS)

    Yamazaki, Dai; O'Loughlin, Fiachra; Trigg, Mark; Bates, Paul

    2015-04-01

    River width is a fundamental parameter of river hydrodynamic simulations, but no global-scale river width database based on observed water bodies has yet been developed. Here we present a new algorithm that automatically calculates river width from satellite-based water masks and flow direction maps. The Global Width Database for Large Rivers (GWD-LR) is developed by applying the algorithm to the SRTM Water Body Database and the HydroSHEDS flow direction map. Both bank-to-bank river width and effective river width excluding islands are calculated for river channels between 60S and 60N. The effective river width of GWD-LR is compared with existing river width databases for the Congo and Mississippi Rivers. The effective river width of the GWD-LR is slightly narrower compared to the existing databases, but the relative difference is within +/-20% for most river channels. As the river width of the GWD-LR is calculated along the river channels of the HydroSHEDS flow direction map, it is relatively straightforward to apply the GWD-LR to global- and continental-scale river modeling.

  4. Forecasting front displacements with a satellite based ocean forecasting (SOFT) system

    NASA Astrophysics Data System (ADS)

    Alvarez, A.; Orfila, A.; Basterretxea, G.; Tintoré, J.; Vizoso, G.; Fornes, A.

    2007-03-01

    Relatively long term time series of satellite data are nowadays available. These spatio-temporal time series of satellite observations can be employed to build empirical models, called satellite based ocean forecasting (SOFT) systems, to forecast certain aspects of future ocean states. The forecast skill of SOFT systems predicting the sea surface temperature (SST) at sub-basin spatial scale (from hundreds to thousand kilometres), has been extensively explored in previous works. Thus, these works were mostly focussed on predicting large scale patterns spatially stationary. At spatial scales smaller than sub-basin (from tens to hundred kilometres), spatio-temporal variability is more complex and propagating structures are frequently present. In this case, traditional SOFT systems based on Empirical Orthogonal Function (EOF) decompositions could not be optimal prediction systems. Instead, SOFT systems based on Complex Empirical Orthogonal Functions (CEOFs) are, a priori, better candidates to resolve these cases. In this work we study and compare the performance of an EOF and CEOF based SOFT systems forecasting the SST at weekly time scales of a propagating mesoscale structure. The SOFT system was implemented in an area of the Northern Balearic Sea (Western Mediterranean Sea) where a moving frontal structure is recurrently observed. Predictions from both SOFT systems are compared with observations and with the predictions obtained from persistence models. Results indicate that the implemented SOFT systems are superior in terms of predictability to persistence. No substantial differences have been found between the EOF and CEOF-SOFT systems.

  5. Utilizing Satellite-based and Reanalysis Precipitation Data in Hydrological Modeling

    NASA Astrophysics Data System (ADS)

    Ignatius, A. R.; Grundstein, A.; Rasmussen, T. C.; Mote, T. L.; Shepherd, J. M.

    2010-12-01

    Precipitation is an essential input into surface hydrologic models. While rain gauges are the most common source for precipitation data, many regions suffer from a paucity of precipitation data at appropriate temporal and spatial resolutions. Satellite-based or gridded reanalysis data sources provide alternative rainfall inputs for hydrologic models. The University of Georgia and U.S. Dept. of Energy Savannah River National Laboratory are investigating complex hydrometeorological and source attribution problems using a combination of hydrologic observations and models. The project investigates the use several NASA products including TRMM 3B42, TRMM 3B42RT, and MERRA (Modern Era Retrospective-Analysis for Research and Applications) reanalysis data. These data are used as meteorological inputs for a hydrologic model of the Savannah River watershed, located in Georgia and South Carolina. Hydrologic simulations are performed using the BASINS 4.0 (Better Assessment Science Integrating Point and Non-Point Sources) environmental analysis system and the HSPF hydrologic model. Validation studies of the precipitation datasets along with comparisons of streamflow simulations using the alternative inputs will be presented. The work represents a synergy of scientific analysis and stakeholder applications that the forthcoming GPM era can leverage.

  6. Global terrestrial carbon cycle

    SciTech Connect

    Smith, T.M.; Cramer, W.P.; Dixon, R.K.; Leemans, R.; Neilson, R.P.

    1993-01-01

    There is great uncertainty with regard to the future role of the terrestrial biosphere in the global carbon cycle. The uncertainty arises from both an inadequate understanding of current pools and fluxes as well as the potential effects of rising atmospheric concentrations of CO2 on natural ecosystems. Despite these limitations, a number of studies have estimated current and future patterns of terrestrial carbon storage. Future estimates focus on the effects of a climate change associated with a doubled atmospheric concentration of CO2. Available models for examining the dynamics of terrestrial carbon storage and the potential role of forest management and landuse practices on carbon conservation and sequestration are discussed. (Copyright (c) 1993 Kluwer Academic Publishers.)

  7. Advances In Global Aerosol Modeling Applications Through Assimilation of Satellite-Based Lidar Measurements

    NASA Astrophysics Data System (ADS)

    Campbell, James; Hyer, Edward; Zhang, Jianglong; Reid, Jeffrey; Westphal, Douglas; Xian, Peng; Vaughan, Mark

    2010-05-01

    Modeling the instantaneous three-dimensional aerosol field and its downwind transport represents an endeavor with many practical benefits foreseeable to air quality, aviation, military and science agencies. The recent proliferation of multi-spectral active and passive satellite-based instruments measuring aerosol physical properties has served as an opportunity to develop and refine the techniques necessary to make such numerical modeling applications possible. Spurred by high-resolution global mapping of aerosol source regions, and combined with novel multivariate data assimilation techniques designed to consider these new data streams, operational forecasts of visibility and aerosol optical depths are now available in near real-time1. Active satellite-based aerosol profiling, accomplished using lidar instruments, represents a critical element for accurate analysis and transport modeling. Aerosol source functions, alone, can be limited in representing the macrophysical structure of injection scenarios within a model. Two-dimensional variational (2D-VAR; x, y) assimilation of aerosol optical depth from passive satellite observations significantly improves the analysis of the initial state. However, this procedure can not fully compensate for any potential vertical redistribution of mass required at the innovation step. The expense of an inaccurate vertical analysis of aerosol structure is corresponding errors downwind, since trajectory paths within successive forecast runs will likely diverge with height. In this paper, the application of a newly-designed system for 3D-VAR (x,y,z) assimilation of vertical aerosol extinction profiles derived from elastic-scattering lidar measurements is described [Campbell et al., 2009]. Performance is evaluated for use with the U. S. Navy Aerosol Analysis and Prediction System (NAAPS) by assimilating NASA/CNES satellite-borne Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) 0.532 ?m measurements [Winker et al., 2009]. Inversion retrievals of aerosol extinction are performed for one-degree latitudinal averages of CALIOP backscatter signal (thus matching the horizontal resolution of NAAPS) by constraining total column transmission using the model estimate of AOD at the corresponding wavelength. As such, this system serves as a post-processing module predicated on newly-operational NAAPS aerosol analysis fields that feature 2D-VAR assimilation of NASA Moderate Resolution Infrared Spectroradiometer (MODIS) AOD observations [Zhang and Reid, 2006; Zhang et al., 2008]. We describe the influence of 3D-VAR assimilation on NAAPS analyses and forecasts by considering the physical evolution of Saharan dust plumes during their advection across the tropical Atlantic basin. Steps taken towards characterizing spatial covariance parameters that broaden the horizontal influence of information obtained along the limited lidar orbital swath are discussed. This latter context is critical when comparing the efficacy and impact of 3D-VAR assimilation with that of 2D-VAR procedures, which benefit from passive observations with a relatively wide field-of-view and, therefore, greater/more routine global coverage. With multiple satellite-lidar projects either pending launch or in design stages, including the dual ESA missions (AEOLUS and EarthCARE), we describe the potential impact of future 3D-VAR assimilation activities; both for NAAPS forecast capabilities, and the anticipated growth in aerosol transport modeling efforts at federal and cooperative global agencies worldwide. 1 http://www.nrlmry.navy.mil/aerosol/ References Campbell, J. R., J. S. Reid, D. L. Westphal, J. Zhang, E. J. Hyer, and E. J. Welton, CALIOP aerosol subset processing for global aerosol transport model data assimilation, in press, J. Selected Topics Appl. Earth Obs. Rem. Sens., December 2009. Winker, D. M., M. A. Vaughan, A. Omar, Y. Hu, K. A. Powell, Z. Liu, W. H. Hunt, and S. A. Young, Overview of the CALIPSO mission and CALIOP data processing algorithms, J. Atmos. Oceanic. Technol., 26, DOI:10.1175/2009JTECHA1281.1, 2009. Zhang,

  8. Comparison of ground and satellite based measurements of the fraction of photosynthetically active radiation intercepted by tall-grass prairie

    NASA Technical Reports Server (NTRS)

    Demetriades-Shah, T. H.; Kanemasu, E. T.; Flitcroft, I.; Su, H.

    1990-01-01

    The fraction, of photosynthetically active radiation absorbed by vegetation, F sub ipar, is an important requirement for estimating vegetation biomass productivity and related quantities. This was an integral part of a large international effort; the First ISLSCP Field Experiment (FIFE). The main objective of FIFE was to study the effects of vegetation on the land atmosphere interactions and to determine if these interactions can be assessed from satellite spectral measurements. The specific purpose of this experiment was to find out how well measurements of F sub ipar relate to ground, helicopter, and satellite based spectral reflectance measurements. Concurrent measurements of F sub ipar and ground, helicopter, and satellite based measurements were taken at 13 tall grass prairie sites in Kansas. The sites were subjected to various combinations of burning and grazing managements.

  9. Satellite-based augmentation systems: A novel and cost-effective tool for ionospheric and space weather studies

    NASA Astrophysics Data System (ADS)

    Sunda, Surendra; Sridharan, R.; Vyas, B. M.; Khekale, P. V.; Parikh, K. S.; Ganeshan, A. S.; Sudhir, C. R.; Satish, S. V.; Bagiya, Mala S.

    2015-01-01

    Satellite-Based Augmentation Systems (SBASes) are designed to provide additional accuracy and robustness to existing satellite-based radio navigation systems for all phases of a flight. However, similar to navigation systems such as GPS which has proven its worth for the investigation of the ionosphere, the SBASes do have certain advantages. In the present paper, we propose and demonstrate SBAS applicability to ionospheric and space weather research in a novel and cost-effective way. The recent commissioning of the Indian SBAS, named GPS Aided Geo Augmented Navigation (GAGAN), covering the equatorial and low-latitude regions centered around the Indian longitudes provides the motivation for this approach. Two case studies involving different ionospheric behavior over low-latitude regions vindicate the potential of SBAS over extended areas.

  10. Satellite-based quantification of the bottom trawling induced sediment resuspension over an entire shelf

    NASA Astrophysics Data System (ADS)

    Oberle, F. J.; Cheriton, O. M.; Hanebuth, T. J. J.

    2014-12-01

    The effect of bottom trawling activities on continental shelves has been a topic of interest for both fishery resource studies and ecological impact studies for a while. However, the impact of demersal fishing gear was almost exclusively studied from a perspective of its effects on benthic fauna, but recently it has also attracted attention due to its profound impact on sediments. Here we present the first study to quantify the trawling-induced sediment resuspension effect by combining satellite-based spatial patterns of bottom trawling with quantitative measurements of induced sediment plumes. This study examined high-resolution GPS vessel monitoring data from one year (2011-2012) to quantify the sedimentary budget caused by bottom trawling activity for the entire NW Iberian shelf, an area that is widely affected by chronic (continuous and intensive) commercial bottom trawling and is exemplary for many other narrow shelves worldwide. By filtering the GPS data by vessel type, vessel speed, and geometry of the trawl path, we resolved geographically detailed bottom trawling activities with varying local trawling intensities depending both on legal restrictions and bedrock geomorphology. Initial results show that trawling-induced resuspended sediments mark a significant if not dominant factor for a source to sink sedimentary budget, as they are calculated to be approximately two times as large as fluvial sedimentary input to the shelf. Ultimately, these results not only allow for a trawling affected sediment budget but also significantly help with marine management decisions by allowing to predict the mobilization and transport of sediment caused by bottom trawling gear at the level of a specific fishing fleet or ecosystem.

  11. [Accuracy evaluation of the TRMM satellite-based precipitation data over the mid-high latitudes].

    PubMed

    Cai, Yan-Cong; Jin, Chang-Jie; Wang, An-Zhi; Guan, De-Xin; Wu, Jia-Bing; Yuan, Feng-Hui; Xu, Lei-Lei; Bu, Chang-Qian

    2014-11-01

    Satellite-based precipitation product plays a significant role in analyzing spatial pattern of precipitation. TRMM 3B42 (3B42), as one of important precipitation products, is a key forcing factor for ecological, climate and hydrological models with its sufficient spatial and temporal scales. At present, there is still limited knowledge of accuracy and error structure of new version 3B42 V7, especially the lack of evaluating its accuracy in regions of mid-high latitudes, which restricts its application in the field of ecology, climate and hydrology. Based on 3B42 V7 product and data obtained from 53 weather stations in the period of 1998-2012 over Inner Mongolia, the paper evaluated the accuracy of 3B42 and revealed the spatial distribution of accuracy evaluation indices and its influencing factors. The result of overall accuracy evaluation indicated that there was overestimation of the amount of precipitation by 3B42 at daily, monthly and annual timescales. Error of 3B42 increased with the increasing timescale, and mean error and mean absolute error of daily precipitation were just -0.06 and 0.88 mm, respectively. It showed good performance for detecting the occurrence of rain events with equitable threat score (ETS) of 0.23, but slightly overestimated the frequency of rainy events. Moreover, altitude and average annual precipitation had impacts on data accuracy. The absolute error of precipitation decreased and yet the ability of detecting rain events be- came weak with the increasing altitude, while the effect of average annual precipitation on data accuracy was opposite. PMID:25898629

  12. MTSAT-1R satellite-based overshooting top detection and relationship to precipitation intensity

    NASA Astrophysics Data System (ADS)

    Li, Fu-ning; Yu, Fan

    2014-11-01

    Both satellite-based 11-um infrared window channel brightness temperature (IRW BT) and 6-7-um water vapor minus IRW BT difference (WV-IRW BTD) have been widely used in detection of convective overshooting top (OT). In this paper, considering a significant negative correlation between WV-IRW BTD and IRW BT (<0.7 in 93.07% cases) but a banded distribution, a combined parameter named weighted BTD (WBTD) is constructed for convective OT detection, which offers an improvement over the WV-IRW BTD technique. With this method, MTSAT-1R satellite data and ground station precipitation data during July to September in 2010 in east China are used to research the relationship between OT occurrence and precipitation, also to study the variations of precipitation intensity (PI) and mean WBTD (WBTD_M) during the evolution of convective clouds. The results show that (1) 58.2% of the analyzed OT cases appear a certain rainfall and 46.32% of these precipitation events record over 1mm/10min PI; (2) in all recorded over 1mm/10min precipitation events, OT occurrence probability in the corresponding region is 12.55%, greater probability happens in higher PI, in over 10mm/10min cases, the probability rises to 34%; (3) study in ten groups of strong convective clouds shows a positive correlation (up to 0.9) between WBTD_OI and PI; OT occurrence probability in cloud area is great when convection develops to a strong phase, while very small even no OTs in the early and late of convection.

  13. Categorizing natural disaster damage assessment using satellite-based geospatial techniques

    NASA Astrophysics Data System (ADS)

    Myint, S. W.; Yuan, M.; Cerveny, R. S.; Giri, C.

    2008-07-01

    Remote sensing of a natural disaster's damage offers an exciting backup and/or alternative to traditional means of on-site damage assessment. Although necessary for complete assessment of damage areas, ground-based damage surveys conducted in the aftermath of natural hazard passage can sometimes be potentially complicated due to on-site difficulties (e.g., interaction with various authorities and emergency services) and hazards (e.g., downed power lines, gas lines, etc.), the need for rapid mobilization (particularly for remote locations), and the increasing cost of rapid physical transportation of manpower and equipment. Satellite image analysis, because of its global ubiquity, its ability for repeated independent analysis, and, as we demonstrate here, its ability to verify on-site damage assessment provides an interesting new perspective and investigative aide to researchers. Using one of the strongest tornado events in US history, the 3 May 1999 Oklahoma City Tornado, as a case example, we digitized the tornado damage path and co-registered the damage path using pre- and post-Landsat Thematic Mapper image data to perform a damage assessment. We employed several geospatial approaches, specifically the Getis index, Geary's C, and two lacunarity approaches to categorize damage characteristics according to the original Fujita tornado damage scale (F-scale). Our results indicate strong relationships between spatial indices computed within a local window and tornado F-scale damage categories identified through the ground survey. Consequently, linear regression models, even incorporating just a single band, appear effective in identifying F-scale damage categories using satellite imagery. This study demonstrates that satellite-based geospatial techniques can effectively add spatial perspectives to natural disaster damages, and in particular for this case study, tornado damages.

  14. Development of Satellite-based Climatology of Low-level Cloud and Fog in Mountain Terrain

    NASA Astrophysics Data System (ADS)

    Duan, Y.; Barros, A. P.

    2014-12-01

    The presence of orographic clouds and fog has major environmental and economic implications that the potential shift in the space-time distribution can effectively redistribute freshwater resources and threaten the sustainability of the ecology, geomorphology and hydrology of mountainous regions and adjacent basins. This includes the Southern Appalachian Mountains, which rely closely on the moisture input from fog, cap clouds and light rainfall, as well as cloud forests in the Andes with frequent occurrence of dense fog. However, the applicability of fog forecasting models becomes limited in regions of complex terrain. The motivation of this project is to develop a satellite-based hydroclimatology and physical parameterization of orographic low-level clouds and fog regimes in the Southern Appalachians using a general methodology that can be applied to mountainous regions elsewhere. An algorithm for the detection and extraction of stratus clouds and fog was developed using changes in vertical gradients of CPR reflectivity and liquid water products from almost 5-years of CLOUDSAT and SRTM terrain data. This population of low-level clouds and fog will be analyzed with GOES infrared and visible imagery, MODIS and CALIPSO products, and with airport cloud height and visibility records to expand the spatial coverage beyond narrow satellite sensor swaths. The climatology will be further developed through integration with results from WRF simulations for selected periods since the bulk of the PMM network has been in place (2008-present) to aid in defining meteorological and time-of-day constraints in the interpretation of simulated satellite radar reflectivity profiles. The overarching goal is to infer a representation of the diurnal cycle, seasonal and inter-annual variations of the vertical distribution of LWC and hydrometeors in orographic clouds and fog that vary spatially with landform toward developing a more general parameterization of seeder-feeder interactions in microphysical models.

  15. Adjusting thresholds of satellite-based convective initiation interest fields based on the cloud environment

    NASA Astrophysics Data System (ADS)

    Jewett, Christopher P.; Mecikalski, John R.

    2013-11-01

    The Time-Space Exchangeability (TSE) concept states that similar characteristics of a given property are closely related statistically for objects or features within close proximity. In this exercise, the objects considered are growing cumulus clouds, and the data sets to be considered in a statistical sense are geostationary satellite infrared (IR) fields that help describe cloud growth rates, cloud top heights, and whether cloud tops contain significant amounts of frozen hydrometeors. In this exercise, the TSE concept is applied to alter otherwise static thresholds of IR fields of interest used within a satellite-based convective initiation (CI) nowcasting algorithm. The convective environment in which the clouds develop dictate growth rate and precipitation processes, and cumuli growing within similar mesoscale environments should have similar growth characteristics. Using environmental information provided by regional statistics of the interest fields, the thresholds are examined for adjustment toward improving the accuracy of 0-1 h CI nowcasts. Growing cumulus clouds are observed within a CI algorithm through IR fields for many 1000 s of cumulus cloud objects, from which statistics are generated on mesoscales. Initial results show a reduction in the number of false alarms of ~50%, yet at the cost of eliminating approximately ~20% of the correct CI forecasts. For comparison, static thresholds (i.e., with the same threshold values applied across the entire satellite domain) within the CI algorithm often produce a relatively high probability of detection, with false alarms being a significant problem. In addition to increased algorithm performance, a benefit of using a method like TSE is that a variety of unknown variables that influence cumulus cloud growth can be accounted for without need for explicit near-cloud observations that can be difficult to obtain.

  16. Recent satellite-based trends of tropospheric nitrogen dioxide over large urban agglomerations worldwide

    NASA Astrophysics Data System (ADS)

    Schneider, P.; Lahoz, W. A.; van der A, R.

    2015-02-01

    Trends in tropospheric nitrogen dioxide (NO2) columns over 66 large urban agglomerations worldwide have been computed using data from the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) instrument onboard the Envisat platform for the period August 2002 to March 2012. A seasonal model including a~linear trend was fitted to the satellite-based time series over each site. The results indicate distinct spatial patterns in trends. While agglomerations in Europe, North America, and some locations in East Asia/Oceania show decreasing tropospheric NO2 levels on the order of -5% yr-1, rapidly increasing levels of tropospheric NO2 are found for agglomerations in large parts of Asia, Africa, and South America. The site with the most rapidly increasing absolute levels of tropospheric NO2 was found to be Tianjin in China with a trend of 3.04 (±0.47) × 1015 molecules cm-2yr-1, whereas the site with the most rapidly increasing relative trend was Kabul in Afghanistan with 14.3 (±2.2) % yr-1. In total, 34 sites exhibited increasing trends of tropospheric NO2 throughout the study period, 24 of which were found to be statistically significant. A total of 32 sites showed decreasing levels of tropospheric NO2 during the study period, of which 20 sites did so at statistically significant magnitudes. Overall, going beyond the relatively small set of megacities investigated previously, this study provides the first consistent analysis of recent changes in tropospheric NO2 levels over most large urban agglomerations worldwide, and indicates that changes in urban NO2 levels are subject to substantial regional differences as well as influenced by economic and demographic factors.

  17. A global, high resolution, satellite-based model of air-sea isoprene flux

    NASA Astrophysics Data System (ADS)

    Erickson, David J., III; Hernandez, Jose L.

    A procedure is described where satellite data from different sensors are merged to compute global air-sea isoprene flux estimates. Observational relationships based on cruise data are used to constrain a global satellite based model of ocean to atmosphere isoprene flux. The strong relationship between surface ocean isoprene concentration and chlorophyll concentration is used to estimate the surface ocean concentration of isoprene on a monthly basis at 2°×2.5° resolution. Monthly mean NASA SeaWiFS chlorophyll estimates are used to drive the isoprene concentration distributions. The global computed range of isoprene in the surface ocean is 1-100 pmol l-1. 4-D assimilated surface meteorological variables from the Data Assimilation Office (DAO) at NASA/GSFC are used to compute the global isoprene transfer velocity field. The range in ocean to atmosphere flux is 0.1-200 ug C m-2 d-1. The global integrated flux of isoprene from the ocean to the atmosphere is 0.085 Tg C yr-1 with an error estimate of at least 100%. This estimate is a factor of 3-10 lower than previous estimates, most likely due to an under representation of the oceanic gyre regions in previous global extrapolations. This procedure will be used in the future when co-located in time and space SeaWiFs data and DAO assimilated meteorological fields are available. Since the atmospheric residence time of isoprene is on the order of hours, the ocean source of isoprene is likely to be critical in determining marine boundary layer O3, OH and general oxidizing capacity in remote marine regions.

  18. Assimilating Satellite-Based Snow Depth and Snow Cover Products to Improve Snow Predictions in Alaska

    NASA Astrophysics Data System (ADS)

    Liu, Y.; Peters-Lidard, C. D.; Kumar, S.; Foster, J. L.; Shaw, M.; Tian, Y.; Fall, G. M.

    2012-12-01

    This presentation discusses a data assimilation study that integrates high-resolution (on the order of 1km) land surface modeling and satellite-based snow observations for improved snow predictions in a region in Alaska, using the NASA Land Information System (LIS). Several snow products are assimilated, both separately and jointly, into the Noah land surface model (version 3.2). These include the standard 500-m snow cover fraction (SCF) product (MOD10A1) from the Moderate-Resolution Imaging Spectroradiometer (MODIS), and the 5-km SCF estimates and snow depth (SD) estimates from a blended snow product derived based on MODIS and the Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) measurements, using the Air Force Weather Agency (AFWA)/NASA Snow Algorithm (ANSA). Comparing to the standard MOD10A1 product, the ANSA SCF product is available at a coarser resolution but has the advantage of reduced data gaps due to cloud cover, by using supplemental information from AMSR-E. The ANSA SD estimates are adjusted against in situ observations via statistical interpolation to reduce the potentially large biases in the dataset prior to the assimilation. An EnKF-based approach is used for assimilating SD, while a customized, rule-based direct insertion approach is developed to assimilate information from the SCF estimates. Overall, the largest improvements on snow prediction are achieved via SD assimilation, while the SCF assimilation results in the best improvement on streamflow prediction. It is noted that filling gaps in the MODIS SCF dataset caused by cloud cover with the AMSR-E product can significantly increase the information content of the SCF data, resulting in substantial improvements on snow and streamflow predictions.

  19. Satellite Based Analysis of Carbon Monoxide Levels Over Alberta Oil Sand

    NASA Astrophysics Data System (ADS)

    Marey, H. S.; Hashisho, Z.; Fu, L.; Gille, J. C.

    2014-12-01

    The rapid expansion of oil sands activities and massive energy requirements to extract and upgrade the bitumen require a comprehensive understanding of their potential environmental impacts, particularly on air quality. In this study, satellite-based analysis of carbon monoxide (CO) levels was used to assess the magnitude and distribution of this pollutant throughout Alberta oil sands region. Measurements of Pollution in the Troposphere (MOPITT) V5 multispectral product that uses both near-infrared and the thermal-infrared radiances for CO retrieval were used. MOPITT-based climatology and inter-annual variations were examined for 12 years (2002-2013) on spatial and temporal scales. Seasonal climatological maps for CO total columns indicated conspicuous spatial variations in all seasons except in winter where the CO spatial variations are less prominent. High CO loadings are observed to extend from the North East to North West regions of Alberta, with highest values in spring. The CO mixing ratios at the surface level in winter and spring seasons exhibited dissimilar spatial distribution pattern where the enhancements are detected in south eastern rather than northern Alberta. Analyzing spatial distributions of Omega at 850 mb pressure level for four seasons implied that, conditions in northeastern Alberta are more favorable for up lofting while in southern Alberta, subsidence of CO emissions are more likely. Time altitude CO profile climatology as well as the inter-annual variability were investigated for the oil sands and main urban regions in Alberta to assess the impact of various sources on CO loading. Monthly variations over urban regions are consistent with the general seasonal cycle of CO in Northern Hemisphere which exhibits significant enhancement in winter and spring, and minimum mixing ratios in summer. The typical seasonal CO variations over the oil sands region are less prominent. This study has demonstrated the potential use of multispectral CO product over Alberta.

  20. Comparison of ground and satellite based measurements of the fraction of photosynthetically active radiation intercepted by tall-grass prairie

    NASA Technical Reports Server (NTRS)

    Demetriades-Shah, T. H.; Kanemasu, E. T.; Flitcroft, I. D.; Su, H.

    1992-01-01

    The fraction of photosynthetically active radiation intercepted by vegetation, F(sub ipar) is an important parameter for modeling the interactions between the land-surface and atmosphere and for estimating vegetation biomass productivity. This study was, therefore, an integral part of FIFE. The specific purpose of this experiment was to find out how well definitive measurements of F(sub ipar) on the ground relate to near-ground and satellite based spectral reflectance measurements. Concurrent measurements of F(sub ipar) and ground, helicopter, and satellite based reflectance measurements were taken at thirteen tall-grass prairie sites within the FIFE experimental area. The sites were subjected to various combinations of burning and grazing managements. The ground and helicopter based reflectance measurements were taken on the same day or few days from the time of the overpass of LANDSAT and SPOT satellites. Ground-based reflectance measurements and sun photometer readings taken at the times of the satellite overpasses were used to correct for atmospheric attenuation. Hand-held radiometer spectral indices were strongly correlated with helicopter and satellite based values (r = 0.94 for helicopter, 0.93 for LANDSAT Thematic Mapper, and 0.86 for SPOT). However, the ground, helicopter, and satellite based normalized difference spectral vegetation indices showed low sensitivity to changes in F(sub ipar). Reflectance measurements were only moderately well correlated with measurements of F(sub ipar) (r = 0.82 for hand-held radiometer, 0.84 for helicopter measurements, and 0.75 for the LANDSAT Thematic Mapper and SPOT). Improved spectral indices which can compensate for site differences are needed in order to monitor F(sub ipar) more reliably.

  1. All Solid-State High-Efficiency Tunable UV Source for Airborne or Satellite-Based Ozone DIAL Systems

    Microsoft Academic Search

    Darrell J. Armstrong; Arlee V. Smith

    2007-01-01

    We designed, built, and tested two laboratory prototype nanosecond UV sources for airborne or satellite-based ozone differential absorption lidar (DIAL) remote-sensing systems. Our prototypes use a 532-nm second-harmonic pulse from a Q-switched injection-seeded Nd:YAG laser to pump an optical parametric oscillator (OPO) that generates a tunable signal wavelength near 803 nm. The OPO signal is mixed with additional 532 nm

  2. Comparison of Historical Satellite-Based Estimates of Solar Radiation Resources with Recent Rotating Shadowband Radiometer Measurements: Preprint

    SciTech Connect

    Myers, D. R.

    2009-03-01

    The availability of rotating shadow band radiometer measurement data at several new stations provides an opportunity to compare historical satellite-based estimates of solar resources with measurements. We compare mean monthly daily total (MMDT) solar radiation data from eight years of NSRDB and 22 years of NASA hourly global horizontal and direct beam solar estimates with measured data from three stations, collected after the end of the available resource estimates.

  3. Satellite-based measurements of surface deformation reveal fluid flow associated with the geological storage of carbon dioxide

    Microsoft Academic Search

    D. W. Vasco; A. Rucci; A. Ferretti; F. Novali; R. C. Bissell; P. S. Ringrose; A. S. Mathieson; I. W. Wright

    2010-01-01

    Interferometric Synthetic Aperture Radar (InSAR) data, gathered over the In Salah CO2 storage project in Algeria, provide an early indication that satellite-based geodetic methods can be effective in monitoring the geological storage of carbon dioxide. An injected mass of 3 million tons of carbon dioxide from one of the first large-scale carbon sequestration efforts, produces a measurable surface displacement of

  4. Comparison of ground and satellite based measurements of the fraction of photosynthetically active radiation intercepted by tall-grass prairie

    NASA Technical Reports Server (NTRS)

    Demetriades-Shah, T. H.; Kanemasu, E. T.; Flitcroft, I.; Su, H.

    1991-01-01

    The fraction, of photosynthetically active radiation intercepted by vegetation, F(sub ipar) is an important parameter for modeling the interactions between the land-surface and atmosphere and for estimating vegetation biomass productivity. This study was; therefore, an integral part of FIFE. The specific purpose of this experiment was to find out how well definitive measurements of F(sub ipar) on the ground relate to near-ground and satellite based spectral reflectance measurements. Concurrent measurements of F(sub ipar) and ground, helicopter, and satellite based reflectance measurements were taken at thirteen tall-grass prairie sites within the FIFE experimental area. The sites were subjected to various combinations of burning and grazing managements. The ground and helicopter based reflectance measurements were taken on the same day or few days from the time of the overpass of LANDSAT and SPOT satellites. Ground-based reflectance measurements and sun photometer readings taken at the times of the satellite overpasses were used to correct for atmospheric attenuation. Hand-held radiometer spectral indices were strongly correlated with helicopter and satellite based values (r=0.94 for helicopter, 0.93 for LANDSAT Thematic Mapper, and 0.86 for SPOT). However, the ground, helicopter, and satellite based normalized difference spectral vegetation indices showed low sensitivity to changes in F(sub ipar). Reflectance measurements were only moderately well correlated with measurements of F(sub ipar) (r=0.82 for hand-held radiometer, 0.84 for helicopter measurements, and 0.75 for the LANDSAT Thematic Mapper and SPOT). Improved spectral indices which can compensate for site differences are needed in order to monitor F(sub ipar) more reliably.

  5. Satellite-based evidence of wavelength-dependent aerosol absorption in biomass burning smoke inferred from Ozone Monitoring Instrument

    Microsoft Academic Search

    H. Jethva; O. Torres

    2011-01-01

    We provide satellite-based evidence of the spectral dependence of absorption in biomass burning aerosols over South America using near-UV measurements made by the Ozone Monitoring Instrument (OMI) during 2005-2007. In the current near-UV OMI aerosol algorithm (OMAERUV), it is implicitly assumed that the only absorbing component in carbonaceous aerosols is black carbon whose imaginary component of the refractive index is

  6. Handbook of the Solar-Terrestrial Environment

    NASA Astrophysics Data System (ADS)

    Breen, Andy

    2009-03-01

    As those of us lucky enough to be involved in the field know, solar system physics (alternately known as solar-terrestrial physics or solar-planetary physics—call it what you will) is a highly active, exciting, and rapidly changing area of science. However, we are not always very good at communicating that excitement to the wider scientific community. This dichotomy—between the excitement of the science and the rather lackluster way in which it is too often communicated—struck me forcibly while reading the book Handbook of the Solar-Terrestrial Environment. Over the past 20 years—roughly since the start of operations of the Ulysses spacecraft, a joint NASA-European Space Agency mission to study the Sun—whole areas of our understanding of the coupled Sun/solar wind/planetary environment system have changed. With Kivelson and Russell's classic undergraduate textbook in the field, Introduction to Space Physics, having been published in 1995 (and with many graduate-level texts covering the entire field being even older), the time is ripe for a new text to provide an overview of the field. Such a book should include the gamut of recent results and outstanding questions. However, this text, Handbook of the Solar-Terrestrial Environment, is not that book.

  7. GLOBAL TERRESTRIAL CARBON CYCLE

    EPA Science Inventory

    There is great uncertainty with regard to the future role of the terrestrial biosphere in the global carbon cycle, arising from both an inadequate understanding of current pools and fluxes as well as the potential effects of rising atmospheric concentrations of CO, on natural eco...

  8. Terrestrial planet formation.

    PubMed

    Righter, K; O'Brien, D P

    2011-11-29

    Advances in our understanding of terrestrial planet formation have come from a multidisciplinary approach. Studies of the ages and compositions of primitive meteorites with compositions similar to the Sun have helped to constrain the nature of the building blocks of planets. This information helps to guide numerical models for the three stages of planet formation from dust to planetesimals (~10(6) y), followed by planetesimals to embryos (lunar to Mars-sized objects; few 10(6) y), and finally embryos to planets (10(7)-10(8) y). Defining the role of turbulence in the early nebula is a key to understanding the growth of solids larger than meter size. The initiation of runaway growth of embryos from planetesimals ultimately leads to the growth of large terrestrial planets via large impacts. Dynamical models can produce inner Solar System configurations that closely resemble our Solar System, especially when the orbital effects of large planets (Jupiter and Saturn) and damping mechanisms, such as gas drag, are included. Experimental studies of terrestrial planet interiors provide additional constraints on the conditions of differentiation and, therefore, origin. A more complete understanding of terrestrial planet formation might be possible via a combination of chemical and physical modeling, as well as obtaining samples and new geophysical data from other planets (Venus, Mars, or Mercury) and asteroids. PMID:21709256

  9. Terrestrial planet formation

    PubMed Central

    Righter, K.; O’Brien, D. P.

    2011-01-01

    Advances in our understanding of terrestrial planet formation have come from a multidisciplinary approach. Studies of the ages and compositions of primitive meteorites with compositions similar to the Sun have helped to constrain the nature of the building blocks of planets. This information helps to guide numerical models for the three stages of planet formation from dust to planetesimals (?106 y), followed by planetesimals to embryos (lunar to Mars-sized objects; few × 106 y), and finally embryos to planets (107–108 y). Defining the role of turbulence in the early nebula is a key to understanding the growth of solids larger than meter size. The initiation of runaway growth of embryos from planetesimals ultimately leads to the growth of large terrestrial planets via large impacts. Dynamical models can produce inner Solar System configurations that closely resemble our Solar System, especially when the orbital effects of large planets (Jupiter and Saturn) and damping mechanisms, such as gas drag, are included. Experimental studies of terrestrial planet interiors provide additional constraints on the conditions of differentiation and, therefore, origin. A more complete understanding of terrestrial planet formation might be possible via a combination of chemical and physical modeling, as well as obtaining samples and new geophysical data from other planets (Venus, Mars, or Mercury) and asteroids. PMID:21709256

  10. NATIVE TERRESTRIAL INVERTEBRATES

    Microsoft Academic Search

    Wayne C. Gagn

    The fint collections of terrestrial invertebrates from the Hawaiian Islands were made during Captain James Cook's voyages in 1778 and 1779. Little of this material was examined scientifically other than by Fabricius (1792-1794), who described the large ichneumon wasp Eclltllromorphufuscator and the vespid hornet Odynem radulu from these collections. The ultimate disposition of specimens, and which ones subsequently survived, became

  11. Volcanic ash - Terrestrial versus extraterrestrial

    NASA Technical Reports Server (NTRS)

    Okeefe, J. A.

    1976-01-01

    A principal difference between terrestrial and extraterrestrial lavas may consist in the greater ability of terrestrial lavas to form thin films (like those of soap bubbles) and hence foams. It would follow that, in place of the pumice and spiny shards found in terrestrial volcanic ash, an extraterrestrial ash should contain minute spherules. This hypothesis may help to explain lunar microspherules.

  12. Arsenic Speciation of Terrestrial Invertebrates

    Microsoft Academic Search

    Maeve M. Moriarty; Iris Koch; Robert A. Gordon; Kenneth J. Reimer

    2009-01-01

    The distribution and chemical form (speciation) of arsenic in terrestrial food chains determines both the amount of arsenic available to higher organisms, and the toxicity of this metalloid in affected ecosystems. Invertebrates are part of complex terrestrial food webs. This paper provides arsenic concentrations and arsenic speciation profiles for eight orders of terrestrial invertebrates collected at three historical gold mine

  13. Hybrid satellite/terrestrial networks: State of the art and future perspectives

    E-print Network

    Papapetrou, Evaggelos

    of communications and navigation of DLR and in the framework of the Satellite Communications Network of ExcellenceHybrid satellite/terrestrial networks: State of the art and future perspectives Nicolas Courville, Hermann Bischl, Erich Lutz, German Aerospace Center (DLR), Institute of Communications and Navigation

  14. Reviving the Goddard Satellite-based Surface Turbulent Fluxes (GSSTF) Dataset

    NASA Astrophysics Data System (ADS)

    Shie, C.; Chiu, L.; Adler, R.; Nelkin, E.; Lin, I.; Xie, P.

    2008-12-01

    The Goddard Satellite-based Surface Turbulent Fluxes datasets, GSSTF1 and GSSTF2 (versions 1 and 2), were officially released in 2000 and 2001, respectively. These datasets (especially GSSTF2 with a longer period and a finer spatial resolution) have been widely used by scientific communities for global energy and water cycle research, and regional and short period data analyses. Accurate sea surface flux measurements are crucial to understand the global water and energy cycles. The oceanic evaporation, which is a major component of the global oceanic fresh water flux, is particularly useful for predicting oceanic circulation and transport. Remote sensing is a valuable tool for global monitoring of these flux measurements. The GSSTF algorithm has been developed and applied to remote sensing research and applications. The research project that produced GSSTF2 (covering a data period of July 1987-December 2000), however, ended in 2001. We have very recently been funded by NASA to resume processing of, and to reprocess, the GSSTF dataset with an objective of continually producing a uniform dataset of sea surface turbulent fluxes, derived from remote sensing data and analysis. The dataset is to be reprocessed and brought up-to-date using improved input datasets. The input datasets, which are currently under processing, include a recently released NCEP sea surface temperature analysis, and a uniform (across satellites) surface wind and microwave brightness temperature V6 dataset (Version 6) from the Special Sensor Microwave Imager (SSM/I) on board the Defense Meteorological Satellite Program (DMSP) satellites produced by Frank Wentz's group of Remote Sensing Systems. Wentz indicated that spurious trends in their wind speed retrievals were removed. Our preliminary analysis indeed shows such an improvement in the retrieved wind speed data from SSM/I V4 to SSM/I V6. A second new product with a finer temporal (12-hr) and spatial (0.25° × 0.25°) resolution (upgraded from the current daily and 1° × 1° GSSTF2) is planned, using an improved SST from Advanced Microwave Scanning Radiometer for the Earth Observing System (AMSR-E) and TRMM Microwave Imager (TMI), and ocean surface wind vector from the Quick Scatterometer (QuikSCAT) and Advanced Earth Observing Satellite II (ADEOS2) SeaWinds. These two developing products (1) daily and 1o x 1o GSSTF2b (July 1987-Dec 2008), and (2) 12-hr and 0.25° × 0.25° GSSTF3 (July 1999-Dec 2009) are scheduled to be completed and released for research community use by late 2009 and early 2011, respectively.

  15. Satellite-based assessment of climate controls on US burned area

    NASA Astrophysics Data System (ADS)

    Morton, D. C.; Collatz, G. J.; Wang, D.; Randerson, J. T.; Giglio, L.; Chen, Y.

    2012-06-01

    Climate regulates fire activity through the buildup and drying of fuels and the conditions for fire ignition and spread. Understanding the dynamics of contemporary climate-fire relationships at national and sub-national scales is critical to assess the likelihood of changes in future fire activity and the potential options for mitigation and adaptation. Here, we conducted the first national assessment of climate controls on US fire activity using two satellite-based estimates of monthly burned area (BA), the Global Fire Emissions Database (GFED, 1997-2010) and Monitoring Trends in Burn Severity (MTBS, 1984-2009) BA products. For each US National Climate Assessment (NCA) region, we analyzed the relationships between monthly BA and potential evaporation (PE) derived from reanalysis climate data at 0.5° resolution. US fire activity increased over the past 25 yr, with statistically significant increases in MTBS BA for entire US and the Southeast and Southwest NCA regions. Monthly PE was strongly correlated with US fire activity, yet the climate driver of PE varied regionally. Fire season temperature and shortwave radiation were the primary controls on PE} and fire activity in the Alaska, while water deficit (precipitation - PE) was strongly correlated with fire activity in the Plains regions and Northwest US. BA and precipitation anomalies were negatively correlated in all regions, although fuel-limited ecosystems in the Southern Plains and Southwest exhibited positive correlations with longer lead times (6-12 months). Fire season PE increased from the 1980s-2000s, enhancing climate-driven fire risk in the southern and western US where PE-BA correlations were strongest. Spatial and temporal patterns of increasing fire season PE and BA during the 1990s-2000s highlight the potential sensitivity of US fire activity to climate change in coming decades. However, climate-fire relationships at the national scale are complex, based on the diversity of fire types, ecosystems, and ignition sources within each NCA region. Changes in the seasonality or magnitude of climate anomalies are therefore unlikely to result in uniform changes in US fire activity.

  16. Satellite-based assessment of climate controls on US burned area

    NASA Astrophysics Data System (ADS)

    Morton, D. C.; Collatz, G. J.; Wang, D.; Randerson, J. T.; Giglio, L.; Chen, Y.

    2013-01-01

    Climate regulates fire activity through the buildup and drying of fuels and the conditions for fire ignition and spread. Understanding the dynamics of contemporary climate-fire relationships at national and sub-national scales is critical to assess the likelihood of changes in future fire activity and the potential options for mitigation and adaptation. Here, we conducted the first national assessment of climate controls on US fire activity using two satellite-based estimates of monthly burned area (BA), the Global Fire Emissions Database (GFED, 1997-2010) and Monitoring Trends in Burn Severity (MTBS, 1984-2009) BA products. For each US National Climate Assessment (NCA) region, we analyzed the relationships between monthly BA and potential evaporation (PE) derived from reanalysis climate data at 0.5° resolution. US fire activity increased over the past 25 yr, with statistically significant increases in MTBS BA for the entire US and the Southeast and Southwest NCA regions. Monthly PE was strongly correlated with US fire activity, yet the climate driver of PE varied regionally. Fire season temperature and shortwave radiation were the primary controls on PE and fire activity in Alaska, while water deficit (precipitation - PE) was strongly correlated with fire activity in the Plains regions and Northwest US. BA and precipitation anomalies were negatively correlated in all regions, although fuel-limited ecosystems in the Southern Plains and Southwest exhibited positive correlations with longer lead times (6-12 months). Fire season PE increased from the 1980's-2000's, enhancing climate-driven fire risk in the southern and western US where PE-BA correlations were strongest. Spatial and temporal patterns of increasing fire season PE and BA during the 1990's-2000's highlight the potential sensitivity of US fire activity to climate change in coming decades. However, climate-fire relationships at the national scale are complex, based on the diversity of fire types, ecosystems, and ignition sources within each NCA region. Changes in the seasonality or magnitude of climate anomalies are therefore unlikely to result in uniform changes in US fire activity.

  17. Development of a satellite-based nowcasting system for surface solar radiation

    NASA Astrophysics Data System (ADS)

    Limbach, Sebastian; Hungershoefer, Katja; Müller, Richard; Trentmann, Jörg; Asmus, Jörg; Schömer, Elmar; Groß, André

    2014-05-01

    The goal of the RadNowCast project was the development of a tool-chain for a satellite-based nowcasting of the all sky global and direct surface solar radiation. One important application of such short-term forecasts is the computation of the expected energy yield of photovoltaic systems. This information is of great importance for an efficient balancing of power generation and consumption in large, decentralized power grids. Our nowcasting approach is based on an optical-flow analysis of a series of Meteosat SEVIRI satellite images. For this, we extended and combined several existing software tools and set up a series of benchmarks for determining the optimal forecasting parameters. The first step in our processing-chain is the determination of the cloud albedo from the HRV (High Resolution Visible)-satellite images using a Heliosat-type method. The actual nowcasting is then performed by a commercial software system in two steps: First, vector fields characterizing the movement of the clouds are derived from the cloud albedo data from the previous 15 min to 2 hours. Next, these vector fields are combined with the most recent cloud albedo data in order to extrapolate the cloud albedo in the near future. In the last step of the processing, the Gnu-Magic software is used to calculate the global and direct solar radiation based on the forecasted cloud albedo data. For an evaluation of the strengths and weaknesses of our nowcastig system, we analyzed four different benchmarks, each of which covered different weather conditions. We compared the forecasted data with radiation data derived from the real satellite images of the corresponding time steps. The impact of different parameters on the cloud albedo nowcasting and the surface radiation computation has been analysed. Additionally, we could show that our cloud-albedo-based forecasts outperform forecasts based on the original HRV images. Possible future extension are the incorporation of additional data sources, for example NWC-SAF high resolution wind fields, in order to improve the quality of the atmospheric motion fields, and experiments with custom, optimized software components for the optical-flow estimation and the nowcasting.

  18. Satellite-based Assessment of Climate Controls on US Burned Area

    NASA Technical Reports Server (NTRS)

    Morton, D. C.; Collatz, G. J.; Wang, D.; Randerson, J. T.; Giglio, L.; Chen, Y.

    2012-01-01

    Climate regulates fire activity through the buildup and drying of fuels and the conditions for fire ignition and spread. Understanding the dynamics of contemporary climate-fire relationships at national and sub-national scales is critical to assess the likelihood of changes in future fire activity and the potential options for mitigation and adaptation. Here, we conducted the first national assessment of climate controls on US fire activity using two satellite-based estimates of monthly burned area (BA), the Global Fire Emissions Database (GFED, 1997 2010) and Monitoring Trends in Burn Severity (MTBS, 1984 2009) BA products. For each US National Climate Assessment (NCA) region, we analyzed the relationships between monthly BA and potential evaporation (PE) derived from reanalysis climate data at 0.5 resolution. US fire activity increased over the past 25 yr, with statistically significant increases in MTBS BA for entire US and the Southeast and Southwest NCA regions. Monthly PE was strongly correlated with US fire activity, yet the climate driver of PE varied regionally. Fire season temperature and shortwave radiation were the primary controls on PE and fire activity in the Alaska, while water deficit (precipitation PE) was strongly correlated with fire activity in the Plains regions and Northwest US. BA and precipitation anomalies were negatively correlated in all regions, although fuel-limited ecosystems in the Southern Plains and Southwest exhibited positive correlations with longer lead times (6 12 months). Fire season PE in creased from the 1980s 2000s, enhancing climate-driven fire risk in the southern and western US where PE-BA correlations were strongest. Spatial and temporal patterns of increasing fire season PE and BA during the 1990s 2000s highlight the potential sensitivity of US fire activity to climate change in coming decades. However, climatefire relationships at the national scale are complex, based on the diversity of fire types, ecosystems, and ignition sources within each NCA region. Changes in the seasonality or magnitude of climate anomalies are therefore unlikely to result in uniform changes in US fire activity.

  19. The development of potassium tantalate niobate thin films for satellite-based pyroelectric detectors

    SciTech Connect

    Cherry, H B.B. [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering

    1997-05-01

    Potassium tantalate niobate (KTN) pyroelectric detectors are expected to provide detectivities, of 3.7 x 10{sup 11} cmHz {sup {1/2}}W{sup {minus}1} for satellite-based infrared detection at 90 K. The background limited detectivity for a room-temperature thermal detector is 1.8 x 10{sup 10} cmHz{sup {1/2}}W{sup {minus}1}. KTN is a unique ferroelectric for this application because of the ability to tailor the temperature of its pyroelectric response by adjusting its ratio of tantalum to niobium. The ability to fabricate high quality KTN thin films on Si-based substrates is crucial to the development of KTN pyroelectric detectors. Si{sub x}N{sub y} membranes created on the Si substrate will provide the weak thermal link necessary to reach background limited detectivities. The device dimensions obtainable by thin film processing are expected to increase the ferroelectric response by 20 times over bulk fabricated KTN detectors. In addition, microfabrication techniques allow for easier array development. This is the first reported attempt at growth of KTN films on Si-based substrates. Pure phase perovskite films were grown by pulsed laser deposition on SrRuO{sub 3}/Pt/Ti/Si{sub x}N{sub y}/Si and SrRuO{sub 3}/Si{sub x}N{sub y}/Si structures; room temperature dielectric permittivities for the KTN films were 290 and 2.5, respectively. The dielectric permittivity for bulk grown, single crystal KTN is {approximately}380. In addition to depressed dielectric permittivities, no ferroelectric hysteresis was found between 80 and 300 K for either structure. RBS, AES, TEM and multi-frequency dielectric measurements were used to investigate the origin of this apparent lack of ferroelectricity. Other issues addressed by this dissertation include: the role of oxygen and target density during pulsed laser deposition of KTN thin films; the use of YBCO, LSC and Pt as direct contact bottom electrodes to the KTN films, and the adhesion of the bottom electrode layers to Si{sub x}N{sub y}/Si.

  20. Satellite-based PM concentrations and their application to COPD in Cleveland, OH

    PubMed Central

    Kumar, Naresh; Liang, Dong; Comellas, Alejandro; Chu, Allen D.; Abrams, Thad

    2014-01-01

    A hybrid approach is proposed to estimate exposure to fine particulate matter (PM2.5) at a given location and time. This approach builds on satellite-based aerosol optical depth (AOD), air pollution data from sparsely distributed Environmental Protection Agency (EPA) sites and local time–space Kriging, an optimal interpolation technique. Given the daily global coverage of AOD data, we can develop daily estimate of air quality at any given location and time. This can assure unprecedented spatial coverage, needed for air quality surveillance and management and epidemiological studies. In this paper, we developed an empirical relationship between the 2 km AOD and PM2.5 data from EPA sites. Extrapolating this relationship to the study domain resulted in 2.3 million predictions of PM2.5 between 2000 and 2009 in Cleveland Metropolitan Statistical Area (MSA). We have developed local time–space Kriging to compute exposure at a given location and time using the predicted PM2.5. Daily estimates of PM2.5 were developed for Cleveland MSA between 2000 and 2009 at 2.5 km spatial resolution; 1.7 million (~79.8%) of 2.13 million predictions required for multiyear and geographic domain were robust. In the epidemiological application of the hybrid approach, admissions for an acute exacerbation of chronic obstructive pulmonary disease (AECOPD) was examined with respect to time–space lagged PM2.5 exposure. Our analysis suggests that the risk of AECOPD increases 2.3% with a unit increase in PM2.5 exposure within 9 days and 0.05° (~5 km) distance lags. In the aggregated analysis, the exposed groups (who experienced exposure to PM2.5 >15.4 ?g/m3) were 54% more likely to be admitted for AECOPD than the reference group. The hybrid approach offers greater spatiotemporal coverage and reliable characterization of ambient concentration than conventional in situ monitoring-based approaches. Thus, this approach can potentially reduce exposure misclassification errors in the conventional air pollution epidemiology studies. PMID:24045428

  1. Towards a Near Real-Time Satellite-Based Flux Monitoring System for the MENA Region

    NASA Astrophysics Data System (ADS)

    Ershadi, A.; Houborg, R.; McCabe, M. F.; Anderson, M. C.; Hain, C.

    2013-12-01

    Satellite remote sensing has the potential to offer spatially and temporally distributed information on land surface characteristics, which may be used as inputs and constraints for estimating land surface fluxes of carbon, water and energy. Enhanced satellite-based monitoring systems for aiding local water resource assessments and agricultural management activities are particularly needed for the Middle East and North Africa (MENA) region. The MENA region is an area characterized by limited fresh water resources, an often inefficient use of these, and relatively poor in-situ monitoring as a result of sparse meteorological observations. To address these issues, an integrated modeling approach for near real-time monitoring of land surface states and fluxes at fine spatio-temporal scales over the MENA region is presented. This approach is based on synergistic application of multiple sensors and wavebands in the visible to shortwave infrared and thermal infrared (TIR) domain. The multi-scale flux mapping and monitoring system uses the Atmosphere-Land Exchange Inverse (ALEXI) model and associated flux disaggregation scheme (DisALEXI), and the Spatial and Temporal Adaptive Reflectance Fusion Model (STARFM) in conjunction with model reanalysis data and multi-sensor remotely sensed data from polar orbiting (e.g. Landsat and MODerate resolution Imaging Spectroradiometer (MODIS)) and geostationary (MSG; Meteosat Second Generation) satellite platforms to facilitate time-continuous (i.e. daily) estimates of field-scale water, energy and carbon fluxes. Within this modeling system, TIR satellite data provide information about the sub-surface moisture status and plant stress, obviating the need for precipitation input and a detailed soil surface characterization (i.e. for prognostic modeling of soil transport processes). The STARFM fusion methodology blends aspects of high frequency (spatially coarse) and spatially fine resolution sensors and is applied directly to flux output fields to facilitate daily mapping of fluxes at sub-field scales. A complete processing infrastructure to automatically ingest and pre-process all required input data and to execute the integrated modeling system for near real-time agricultural monitoring purposes over targeted MENA sites is being developed, and initial results from this concerted effort will be discussed.

  2. Development and Comparison of Ground and Satellite-based Retrievals of Cirrus Cloud Physical Properties

    SciTech Connect

    Mitchell, David L

    2009-10-14

    This report is the final update on ARM research conducted at DRI through May of 2006. A relatively minor amount of work was done after May, and last month (November), two journal papers partially funded by this project were published. The other investigator on this project, Dr. Bob d'Entremont, will be submitting his report in February 2007 when his no-cost extension expires. The main developments for this period, which concludes most of the DRI research on this project, are as follows: (1) Further development of a retrieval method for cirrus cloud ice particle effective diameter (De) and ice water path (IWP) using terrestrial radiances measured from satellites; (2) Revision and publication of the journal article 'Testing and Comparing the Modified Anomalous Diffraction Approximation'; and (3) Revision and publication of our radar retrieval method for IWC and snowfall rate.

  3. Human proximity effects on circular polarized handset antennas in personal satellite communications

    Microsoft Academic Search

    Joseph S. Colburn; Yahya Rahmat-Samii

    1998-01-01

    Satellite-based systems are the next step in mobile communications. Several low and medium Earth orbit mobile communication satellite systems have been proposed and are currently being deployed. For all these systems, high-performance circularly polarized antennas for the mobile terminals are of importance. Although considerable material is available on circularly polarized antennas, there is an absence of information on how the

  4. An investigation of the military applications of commercial personal satellite-communications systems

    Microsoft Academic Search

    T. Mahoney; P. Kerr; B. Felstead; P. Wells; M. Cunningham; G. Baumgartner; L. Jeromin

    1999-01-01

    This paper provides a summary of the results of a four-nation workshop that investigated the military use of commercial satellite-based personal communications systems (SPCS). Military considerations and nine potential application areas are described. Of the fifteen vulnerability of SPCS examined in the workshop, six of the more important vulnerabilities (jamming, detection, position location, interception, communications security, and system and network

  5. Terrestrial Laser Scanning

    Microsoft Academic Search

    Mathias Lemmens

    \\u000a Since the early 2000s terrestrial laser scanning has evolved from a research and development (R&D) topic to a geo-data technology,\\u000a which is commercially offered by a multitude of land surveying companies and other service providers all over the world. The\\u000a technology is primarily used for the rapid acquisition of three-dimensional (3D) information of a variety of topographic and\\u000a industrial objects.

  6. Terrestrial Exoplanet Light Curves

    E-print Network

    Eric Gaidos; Nicholas Moskovitz; Darren M. Williams

    2005-11-23

    The phase or orbital light curves of extrasolar terrestrial planets in reflected or emitted light will contain information about their atmospheres and surfaces complementary to data obtained by other techniques such as spectrosopy. We show calculated light curves at optical and thermal infrared wavelengths for a variety of Earth-like and Earth-unlike planets. We also show that large satellites of Earth-sized planets are detectable, but may cause aliasing effects if the lightcurve is insufficiently sampled.

  7. Terrestrial Gravity Fluctuations

    E-print Network

    Harms, Jan

    2015-01-01

    The article reviews the current state of the field, and also presents new analyses especially with respect to the impact of seismic scattering on gravity perturbations, active gravity noise cancellation, and time-domain models of gravity perturbations from atmospheric and seismic point sources. Our understanding of terrestrial gravity fluctuations will have great impact on the future development of GW detectors and high-precision gravimetry in general, and many open questions need to be answered still as emphasized in this article.

  8. Terrestrial Gravity Fluctuations

    E-print Network

    Jan Harms

    2015-07-21

    The article reviews the current state of the field, and also presents new analyses especially with respect to the impact of seismic scattering on gravity perturbations, active gravity noise cancellation, and time-domain models of gravity perturbations from atmospheric and seismic point sources. Our understanding of terrestrial gravity fluctuations will have great impact on the future development of GW detectors and high-precision gravimetry in general, and many open questions need to be answered still as emphasized in this article.

  9. Biological Indicator of Manganese54 Contamination in Terrestrial Environments

    Microsoft Academic Search

    Raffaele Cavalloro; Oscar Ravera

    1966-01-01

    THE value of Unio molluscs as indicators of manganese-54 contamination in freshwater environments has been discussed in an earlier communication1. We have attempted to find a similar indicator for terrestrial environments, and have concluded that the red slug Arion rufus, L. (Gasteropoda, Stylommatophora), may fulfil this role.

  10. Spread spectrum synchronization for a LEO personal communications satellite system

    Microsoft Academic Search

    D. E. Dodds; M. Moher

    1995-01-01

    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

  11. Source mass eruption rate retrieved from satellite-based data using statistical modelling

    NASA Astrophysics Data System (ADS)

    Gouhier, Mathieu; Guillin, Arnaud; Azzaoui, Nourddine; Eychenne, Julia; Valade, Sébastien

    2015-04-01

    Ash clouds emitted during volcanic eruptions have long been recognized as a major hazard likely to have dramatic consequences on aircrafts, environment and people. Thus, the International Civil Aviation Organization (ICAO) established nine Volcanic Ash Advisory Centers (VAACs) around the world, whose mission is to forecast the location and concentration of ash clouds over hours to days, using volcanic ash transport and dispersion models (VATDs). Those models use input parameters such as plume height (PH), particle size distribution (PSD), and mass eruption rate (MER), the latter being a key parameter as it directly controls the amount of ash injected into the atmosphere. The MER can be obtained rather accurately from detailed ground deposit studies, but this method does not match the operational requirements in case of a volcanic crisis. Thus, VAACs use empirical laws to determine the MER from the estimation of the plume height. In some cases, this method can be difficult to apply, either because plume height data are not available or because uncertainties related to this method are too large. We propose here an alternative method based on the utilization of satellite data to assess the MER at the source, during explosive eruptions. Satellite-based techniques allow fine ash cloud loading to be quantitatively retrieved far from the source vent. Those measurements can be carried out in a systematic and real-time fashion using geostationary satellite, in particular. We tested here the relationship likely to exist between the amount of fine ash dispersed in the atmosphere and of coarser tephra deposited on the ground. The sum of both contributions yielding an estimate of the MER. For this purpose we examined 19 eruptions (of known duration) in detail for which both (i) the amount of fine ash dispersed in the atmosphere, and (ii) the mass of tephra deposited on the ground have been estimated and published. We combined these data with contextual information that may influence the statistical relationship such as the magma composition or the existence of phreatomagmatism. In order to infer the relationship between ash content in the atmosphere and the amount of tephra on the ground, we used advanced statistic modelling using model selection, with AIC-type (Akaike Information Criterion) penalization, and classification. First we show that a reliable statistical relationship does exist between atmospheric fine ash and tephra fall deposits. Then we show that magma composition does have an effect on this relationship. It follows a power function in the form S_1=c_0{S_2}c_1(P_n))Hc_2 having a coefficient of determination r2=0.91 and a prediction error of 2.16 at a confidence level of 95%. S1 is the mass of tephra fall deposits and S2 is the fine ash cloud mass as retrieved from satellite measurements. H is the plume height, c0 and c2 are constant coefficients while c1 is variable and depends on the magma composition type (Pn=1:3). This method greatly improves the prediction capability of the source MER as compared to the one based on the plume height solely. If available in real-time, satellite data might be advantageously used as a proxy by the VAACs, to derive key source parameters such as the MER.

  12. Assimilation of Satellite Based Soil Moisture Data in the National Weather Service's Flash Flood Guidance System

    NASA Astrophysics Data System (ADS)

    Seo, D.; Lakhankar, T.; Cosgrove, B.; Khanbilvardi, R.

    2012-12-01

    Climate change and variability increases the probability of frequency, timing, intensity, and duration of flood events. After rainfall, soil moisture is the most important factor dictating flash flooding, since rainfall infiltration and runoff are based on the saturation of the soil. It is difficult to conduct ground-based measurements of soil moisture consistently and regionally. As such, soil moisture is often derived from models and agencies such as the National Oceanic and Atmospheric Administration's National Weather Service (NOAA/NWS) use proxy estimates of soil moisture at the surface in order support operational flood forecasting. In particular, a daily national map of Flash Flood Guidance (FFG) is produced that is based on surface soil moisture deficit and threshold runoff estimates. Flash flood warnings are issued by Weather Forecast Offices (WFOs) and are underpinned by information from the Flash Flood Guidance (FFG) system operated by the River Forecast Centers (RFCs). This study analyzes the accuracy and limitations of the FFG system using reported flash flood cases in 2010 and 2011. The flash flood reports were obtained from the NWS Storm Event database for the Arkansas-Red Basin RFC (ABRFC). The current FFG system at the ABRFC provides gridded flash flood guidance (GFFG) System using the NWS Hydrology Laboratory-Research Distributed Hydrologic Model (HL-RDHM) to translate the upper zone soil moisture to estimates of Soil Conservation Service Curve Numbers. Comparison of the GFFG and real-time Multi-sensor Precipitation Estimator derived Quantitative Precipitation Estimate (QPE) for the same duration and location were used to analyze the success of the system. Improved flash flood forecasting requires accurate and high resolution soil surface information. The remote sensing observations of soil moisture can improve the flood forecasting accuracy. The Soil Moisture Active and Passive (SMAP) and Soil Moisture and Ocean Salinity (SMOS) satellites are two potential sources of remotely sensed soil moisture data. SMOS measures the microwave radiation emitted from the Earth's surface operating at L-band (1.20-1.41 GHz) to measure surface soil moisture directly. Microwave radiation at this wavelength offers relatively deeper penetration and has lower sensitivity to vegetation impacts. The main objective of this research is to evaluate the contribution of remote sensing technology to quantifiable improvements in flash flood applications as well as adding a remote sensing component to the NWS FFG Algorithm. The challenge of this study is employing the direct soil moisture data from SMOS to replace the model-calculated soil moisture state which is based on the soil water balance in 4 km x 4 km Hydrologic Rainfall Analysis Project (HRAP) grid cells. In order to determine the value of the satellite data to NWS operations, the streamflow generated by HL-RDHM with and without soil moisture assimilation will be compared to USGS gauge data. Furthermore, we will apply the satellite-based soil moisture data with the FFG algorithm to evaluate how many hits, misses and false alarms are generated. This study will evaluate the value of remote sensing data in constraining the state of the system for main-stem and flash flood forecasting.

  13. Solar terrestrial observatory

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Eight basic solar-terrestrial scientific objectives that benefit from the Shuttle/Platform approach and a program of measurements for each are discussed. The objectives are to understand: (1) solar variability, (2) wave-particle processes, (3) magnetosphere-ionosphere mass transport, (4) the global electric circuit, (5) upper atmospheric dynamics, (6) middle atmospheric chemistry and energetics, (7) lower atmospheric turbidity, and (8) planetary atmospheric waves. A two stage approach to a multidisciplinary payload is developed: an initial STO, that uses a single platform in a low-Earth orbit, and an advanced STO that uses two platforms in differing orbits.

  14. Antarctic terrestrial ecosystems

    SciTech Connect

    Walton, D.W.H.

    1987-01-01

    The Maritime and Continental Antarctic terrestrial ecosystems are considered in the context of environmental impacts - habitat destruction, alien introductions, and pollution. Four types of pollution are considered: nutrients, radionuclides, inert materials, and noxious chemicals. Their ability to recover from perturbation is discussed in the light of present scientific knowledge, and the methods used to control impacts are reviewed. It is concluded that techniques of waste disposal are still inadequate, adequate training in environmental and conservation principles for Antarctic personnel in many countries is lacking, and scientific investigations may be a much more serious threat than tourism to the integrity of these ecosystems. Some priorities crucial to future management are suggested.

  15. Land Data Assimilation of Satellite-Based Soil Moisture Products Using the Land Information System Over the NLDAS Domain

    NASA Technical Reports Server (NTRS)

    Mocko, David M.; Kumar, S. V.; Peters-Lidard, C. D.; Tian, Y.

    2011-01-01

    This presentation will include results from data assimilation simulations using the NASA-developed Land Information System (LIS). Using the ensemble Kalman filter in LIS, two satellite-based soil moisture products from the AMSR-E instrument were assimilated, one a NASA-based product and the other from the Land Parameter Retrieval Model (LPRM). The domain and land-surface forcing data from these simulations were from the North American Land Data Assimilation System Phase-2, over the period 2002-2008. The Noah land-surface model, version 3.2, was used during the simulations. Changes to estimates of land surface states, such as soil moisture, as well as changes to simulated runoff/streamflow will be presented. Comparisons over the NLDAS domain will also be made to two global reference evapotranspiration (ET) products, one an interpolated product based on FLUXNET tower data and the other a satellite- based algorithm from the MODIS instrument. Results of an improvement metric show that assimilating the LPRM product improved simulated ET estimates while the NASA-based soil moisture product did not.

  16. Satellite-Based Evidence of Wavelength-Dependent Aerosol Absorption in Biomass Burning Smoke Inferred from Ozone Monitoring Instrument

    NASA Technical Reports Server (NTRS)

    Jethva, H.; Torres, O.

    2012-01-01

    We provide satellite-based evidence of the spectral dependence of absorption in biomass burning aerosols over South America using near-UV measurements made by the Ozone Monitoring Instrument (OMI) during 2005-2007. In the current near-UV OMI aerosol algorithm (OMAERUV), it is implicitly assumed that the only absorbing component in carbonaceous aerosols is black carbon whose imaginary component of the refractive index is wavelength independent. With this assumption, OMI-derived aerosol optical depth (AOD) is found to be significantly over-estimated compared to that of AERONET at several sites during intense biomass burning events (August-September). Other well-known sources of error affecting the near-UV method of aerosol retrieval do not explain the large observed AOD discrepancies between the satellite and the ground-based observations. A number of studies have revealed strong spectral dependence in carbonaceous aerosol absorption in the near-UV region suggesting the presence of organic carbon in biomass burning generated aerosols. A sensitivity analysis examining the importance of accounting for the presence of wavelength-dependent aerosol absorption in carbonaceous particles in satellite-based remote sensing was carried out in this work. The results convincingly show that the inclusion of spectrally-dependent aerosol absorption in the radiative transfer calculations leads to a more accurate characterization of the atmospheric load of carbonaceous aerosols.

  17. Air-sea fluxes and satellite-based estimation of water masses formation

    NASA Astrophysics Data System (ADS)

    Sabia, Roberto; Klockmann, Marlene; Fernandez-Prieto, Diego; Donlon, Craig

    2015-04-01

    Recent work linking satellite-based measurements of sea surface salinity (SSS) and sea surface temperature (SST) with traditional physical oceanography has demonstrated the capability of generating routinely satellite-derived surface T-S diagrams [1] and analyze the distribution/dynamics of SSS and its relative surface density with respect to in-situ measurements. Even more recently [2,3], this framework has been extended by exploiting these T-S diagrams as a diagnostic tool to derive water masses formation rates and areas. A water mass describes a water body with physical properties distinct from the surrounding water, formed at the ocean surface under specific conditions which determine its temperature and salinity. The SST and SSS (and thus also density) at the ocean surface are largely determined by fluxes of heat and freshwater. The surface density flux is a function of the latter two and describes the change of the density of seawater at the surface. To obtain observations of water mass formation is of great interest, since they serve as indirect observations of the thermo-haline circulation. The SSS data which has become available through the SMOS [4] and Aquarius [5] satellite missions will provide the possibility of studying also the effect of temporally-varying SSS fields on water mass formation. In the present study, the formation of water masses as a function of SST and SSS is derived from the surface density flux by integrating the latter over a specific area and time period in bins of SST and SSS and then taking the derivative of the total density flux with respect to density. This study presents a test case using SMOS SSS, OSTIA SST, as well as Argo ISAS SST and SSS for comparison, heat fluxes from the NOCS Surface Flux Data Set v2.0, OAFlux evaporation and CMORPH precipitation. The study area, initially referred to the North Atlantic, is extended over two additional ocean basins and the study period covers the 2011-2012 timeframe. Yearly, seasonal and monthly water mass formation rates for different SST and SSS ranges are presented. The formation peaks are remapped geographically, to analyze the extent of the formation area. Water mass formation derived from SMOS and OSTIA compares well with the results obtained from in-situ data, although slight differences in magnitude and peak location occur. Known water masses can then be identified. Ongoing/future work aims at extending this study along different avenues by: 1) expand systematically the spatial and temporal domain of the study to additional ocean basins and to the entire time period of available SSS observations from SMOS/Aquarius; 2) perform a thorough error propagation to assess how errors in satellite SSS and SST translate into errors in water masses formation rates and geographical areas extent; and 3) explore the different options to connect the surface information to the vertical buoyancy structure to assess potential density instability (e.g., Turner angle). References [1] Sabia, R., M. Klockmann, D. Fernández-Prieto, and C. Donlon (2014), A first estimation of SMOS-based ocean surface T-S diagrams, J. Geophys. Res. Oceans, 119, 7357-7371, doi:10.1002/2014JC010120. [2] Klockmann, M., R. Sabia, D. Fernández-Prieto, C. Donlon, J. Font; Towards an estimation of water masses formation areas from SMOS-based T-S diagrams; EGU general assembly 2014, April 27-May 2, 2014. [3] Klockmann, M., R. Sabia, D. Fernández-Prieto, C. Donlon, Linking satellite SSS and SST to water mass formation; Ocean salinity science and salinity remote sensing workshop, Exeter, UK, November 26-28, 2014. [4] Font, J., A. Camps, A. Borges, M. Martín-Neira, J. Boutin, N. Reul, Y. H. Kerr, A. Hahne, and S. Mecklenburg, "SMOS: The challenging sea surface salinity measurement from space," Proceedings of the IEEE, vol. 98, pp. 649-665, 2010. [5] Le Vine, D.M.; Lagerloef, G.S.E.; Torrusio, S.E.; "Aquarius and Remote Sensing of Sea Surface Salinity from Space," Proceedings of the IEEE , vol.98, no.5, pp.688-703, May 2010, doi: 10.1109/JPROC.2010.2040550.

  18. A comprehensive design and performance analysis of LEO satellite quantum communication

    E-print Network

    J. -P. Bourgoin; E. Meyer-Scott; B. L. Higgins; B. Helou; C. Erven; H. Huebel; B. Kumar; D. Hudson; I. D'Souza; R. Girard; R. Laflamme; T. Jennewein

    2012-11-12

    Optical quantum communication utilizing satellite platforms has the potential to extend the reach of quantum key distribution (QKD) from terrestrial limits of ~200 km to global scales. We have developed a thorough numerical simulation using realistic simulated orbits and incorporating the effects of pointing error, diffraction, atmosphere and telescope design, to obtain estimates of the loss and background noise which a satellite-based system would experience. Combining with quantum optics simulations of sources and detection, we determine the length of secure key for QKD, as well as entanglement visibility and achievable distances for fundamental experiments. We analyze the performance of a low Earth orbit (LEO) satellite for downlink and uplink scenarios of the quantum optical signals. We argue that the advantages of locating the quantum source on the ground justify a greater scientific interest in an uplink as compared to a downlink. An uplink with a ground transmitter of at least 25 cm diameter and a 30 cm receiver telescope on the satellite could be used to successfully perform QKD multiple times per week with either an entangled photon source or with a weak coherent pulse source, as well as perform long-distance Bell tests and quantum teleportation. Our model helps to resolve important design considerations such as operating wavelength, type and specifications of sources and detectors, telescope designs, specific orbits and ground station locations, in view of anticipated overall system performance.

  19. Utility Terrestrial Biodiversity Issues

    PubMed

    BREECE; WARD

    1996-11-01

    / Results from a survey of power utility biologists indicate that terrestrial biodiversity is considered a major issue by only a few utilities; however, a majority believe it may be a future issue. Over half of the respondents indicated that their company is involved in some management for biodiversity, and nearly all feel that it should be a goal for resource management. Only a few utilities are funding biodiversity research, but a majority felt more research was needed. Generally, larger utilities with extensive land holdings had greater opportunities and resources for biodiversity management. Biodiversity will most likely be a concern with transmission rights-of-way construction and maintenance, endangered species issues and general land resource management, including mining reclamation and hydro relicensing commitments. Over half of the companies surveyed have established voluntary partnerships with management groups, and biodiversity is a goal in nearly all the joint projects. Endangered species management and protection, prevention of forest fragmentation, wetland protection, and habitat creation and protection are the most common partnerships involving utility companies. Common management practices and unique approaches are presented, along with details of the survey.KEY WORDS: Biodiversity; Utilities; Rights-of-way; Terrestrial; Management PMID:8895401

  20. SOLAR PHYSICS AND TERRESTRIAL EFFECTS Solar-Terrestrial Interactions

    E-print Network

    Mojzsis, Stephen J.

    SOLAR PHYSICS AND TERRESTRIAL EFFECTS Chapter 4 Chapter 4 Solar-Terrestrial Interactions from the charged particles that reach the planet steadily as part of the solar wind and the much it will be deflected into a circular or spiral path by the Lorentz Force. Most charged particles in the solar wind

  1. Satellite Based Live and Interactive Distance Learning Program in the Field of Geoinformatics - a Perspective of Indian Institute of Remote Sensing, India

    NASA Astrophysics Data System (ADS)

    Raju, P. L. N.; Gupta, P. K.; Roy, P. S.

    2011-09-01

    Geoinformatics is a highly specialized discipline that deals with Remote Sensing, Geographical Information System (GIS), Global Positioning System (GPS) and field surveys for assessing, quantification, development and management of resources, planning and infrastructure development, utility services etc. Indian Institute of Remote Sensing (IIRS), a premier institute and one of its kinds has played a key role for capacity Building in this specialized area since its inception in 1966. Realizing the large demand, IIRS has started outreach program in basics of Remote Sensing, GIS and GPS for universities and institutions. EDUSAT (Educational Satellite) is the communication satellite built and launched by ISRO in 2004 exclusively for serving the educational sector to meet the demand for an interactive satellite based distance education system for the country. IIRS has used EDUSAT (shifted to INSAT 4 CR recently due to termination of services from EDUSAT) for its distance learning program to impart basic training in Remote Sensing, GIS and GPS, catering to the universities spread across India. The EDUSAT based training is following similar to e-learning method but has advantage of live interaction sessions between teacher and the students when the lecture is delivered using EDUSAT satellite communication. Because of its good quality reception the interactions are not constrained due to bandwidth problems of Internet. National Natural Resource Management System, Department of Space, Government of India, under Standing Committee in Training and Technology funded this unique program to conduct the basic training in Geoinformatics. IIRS conducts 6 weeks basic training course on "Remote Sensing, GIS and GPS" regularly since the year 2007. The course duration is spread over the period of 3 months beginning with the start of the academic year (1st semester) i.e., July to December every year, for university students. IIRS has utilized EDUSAT satellite for conducting 4 six weeks training course during 2007 till 2009 and INSAT 4CR for conducting the next 2 programs. Till March 2011, fifty four universities with the participation of over 4000 students have benefited from the program (Table 7 and Figure 8). IIRS also organized workshops on "EDUSAT based distance learning: experiences & future learning" in 2007, 09 and 2011. Feedbacks have been taken to address the issues on course structure, duration etc. and plan for improvement in future programs and wider participation. Majority of the participants expressed satisfaction and provided positive feedback and willing to participate in the future programs.

  2. Satellite-based measurements of surface deformation reveal fluid flow associated with the geological storage of carbon dioxide

    NASA Astrophysics Data System (ADS)

    Vasco, D. W.; Rucci, A.; Ferretti, A.; Novali, F.; Bissell, R. C.; Ringrose, P. S.; Mathieson, A. S.; Wright, I. W.

    2010-02-01

    Interferometric Synthetic Aperture Radar (InSAR) data, gathered over the In Salah CO2 storage project in Algeria, provide an early indication that satellite-based geodetic methods can be effective in monitoring the geological storage of carbon dioxide. An injected mass of 3 million tons of carbon dioxide from one of the first large-scale carbon sequestration efforts, produces a measurable surface displacement of approximately 5 mm/year. Using geophysical inverse techniques, we are able to infer flow within the reservoir layer and within a seismically detected fracture/fault zone intersecting the reservoir. We find that, if we use the best available elastic Earth model, the fluid flow need only occur in the vicinity of the reservoir layer. However, flow associated with the injection of the carbon dioxide does appear to extend several kilometers laterally within the reservoir, following the fracture/fault zone.

  3. Using NASA's Giovanni Web Portal to Access and Visualize Satellite-based Earth Science Data in the Classroom

    NASA Technical Reports Server (NTRS)

    Lloyd, Steven; Acker, James G.; Prados, Ana I.; Leptoukh, Gregory G.

    2008-01-01

    One of the biggest obstacles for the average Earth science student today is locating and obtaining satellite-based remote sensing data sets in a format that is accessible and optimal for their data analysis needs. At the Goddard Earth Sciences Data and Information Services Center (GES-DISC) alone, on the order of hundreds of Terabytes of data are available for distribution to scientists, students and the general public. The single biggest and time-consuming hurdle for most students when they begin their study of the various datasets is how to slog through this mountain of data to arrive at a properly sub-setted and manageable data set to answer their science question(s). The GES DISC provides a number of tools for data access and visualization, including the Google-like Mirador search engine and the powerful GES-DISC Interactive Online Visualization ANd aNalysis Infrastructure (Giovanni) web interface.

  4. Evaluation of a moderate resolution, satellite-based impervious surface map using an independent, high-resolution validation data set

    USGS Publications Warehouse

    Jones, J.W.; Jarnagin, T.

    2009-01-01

    Given the relatively high cost of mapping impervious surfaces at regional scales, substantial effort is being expended in the development of moderate-resolution, satellite-based methods for estimating impervious surface area (ISA). To rigorously assess the accuracy of these data products high quality, independently derived validation data are needed. High-resolution data were collected across a gradient of development within the Mid-Atlantic region to assess the accuracy of National Land Cover Data (NLCD) Landsat-based ISA estimates. Absolute error (satellite predicted area - "reference area") and relative error [satellite (predicted area - "reference area")/ "reference area"] were calculated for each of 240 sample regions that are each more than 15 Landsat pixels on a side. The ability to compile and examine ancillary data in a geographic information system environment provided for evaluation of both validation and NLCD data and afforded efficient exploration of observed errors. In a minority of cases, errors could be explained by temporal discontinuities between the date of satellite image capture and validation source data in rapidly changing places. In others, errors were created by vegetation cover over impervious surfaces and by other factors that bias the satellite processing algorithms. On average in the Mid-Atlantic region, the NLCD product underestimates ISA by approximately 5%. While the error range varies between 2 and 8%, this underestimation occurs regardless of development intensity. Through such analyses the errors, strengths, and weaknesses of particular satellite products can be explored to suggest appropriate uses for regional, satellite-based data in rapidly developing areas of environmental significance. ?? 2009 ASCE.

  5. Evaluation of three satellite-based latent heat flux algorithms over forest ecosystems using eddy covariance data.

    PubMed

    Yao, Yunjun; Zhang, Yuhu; Zhao, Shaohua; Li, Xianglan; Jia, Kun

    2015-06-01

    We have evaluated the performance of three satellite-based latent heat flux (LE) algorithms over forest ecosystems using observed data from 40 flux towers distributed across the world on all continents. These are the revised remote sensing-based Penman-Monteith LE (RRS-PM) algorithm, the modified satellite-based Priestley-Taylor LE (MS-PT) algorithm, and the semi-empirical Penman LE (UMD-SEMI) algorithm. Sensitivity analysis illustrates that both energy and vegetation terms has the highest sensitivity compared with other input variables. The validation results show that three algorithms demonstrate substantial differences in algorithm performance for estimating daily LE variations among five forest ecosystem biomes. Based on the average Nash-Sutcliffe efficiency and root-mean-squared error (RMSE), the MS-PT algorithm has high performance over both deciduous broadleaf forest (DBF) (0.81, 25.4 W/m(2)) and mixed forest (MF) (0.62, 25.3 W/m(2)) sites, the RRS-PM algorithm has high performance over evergreen broadleaf forest (EBF) (0.4, 28.1 W/m(2)) sites, and the UMD-SEMI algorithm has high performance over both deciduous needleleaf forest (DNF) (0.78, 17.1 W/m(2)) and evergreen needleleaf forest (ENF) (0.51, 28.1 W/m(2)) sites. Perhaps the lower uncertainties in the required forcing data for the MS-PT algorithm, the complicated algorithm structure for the RRS-PM algorithm, and the calibrated coefficients of the UMD-SEMI algorithm based on ground-measured data may explain these differences. PMID:26017809

  6. Global Communications Infrastructure: CTBT Treaty monitoring using space communications

    NASA Astrophysics Data System (ADS)

    Kebeasy, R.; Abaya, E.; Ricker, R.; Demeules, G.

    Article 1 on Basic Obligations of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) states that: "Each State Party undertakes not to carry out any nuclear weapon test explosion or any other nuclear explosion, and to prohibit and prevent any such nuclear explosion at any place under its jurisdiction or control. Each State Party undertakes, furthermore, to refrain from causing, encouraging, or in any way participating in the carrying out of any nuclear weapon test explosion or any other nuclear explosion." To monitor States Parties compliance with these Treaty provisions, an International Monitoring System (IMS) consisting of 321 monitoring stations and 16 laboratories in some 91 countries is being implemented to cover the whole globe, including its oceans and polar regions. The IMS employs four technologies--seismic, hydroacoustic, infrasound and radionuclide--to detect,locate and identify any seismic event of Richter magnitude 4 and above (equivalent to one kiloton of TNT) that may be associated with a nuclear test explosion. About one-half of this monitoring system is now operational in 67 countries. Monitoring stations send data in near real-time to an International Data Centre (IDC) in Vienna over a Global Communications Infrastructure (GCI) incorporating 10 geostationary satellites plus three satellites in inclined orbits. The satellites relay the data to commercial earth stations, from where they are transferred by terrestrial circuits to the IDC. The IDC automatically processes and interactively analyzes the monitoring data, and distributes the raw data and reports relevant to Treaty verification to National Data Centers in Member States over the same communications network. The GCI will eventually support about 250 thin route VSAT links to the monitoring stations, many of them at remote or harsh locations on the earth, plus additional links to national data centres in various countries. Off-the-shelf VSAT and networking hardware are deployed. This is the first global integrated satellite communications network based on VSAT technology. Space segment has been leased to carry more than 9 gigabytes/day of data to the IDC with a designed annual availability of 99.5%. This paper explains the topology of this satellite-based network, and practical limitations encountered in organizing a single network with 250 links that span the majority of countries in the world, plus the Antarctic regions and the earth's oceans. Having now installed about half of the satellite links in 67 countries, CTBTO has had to hurdle regulatory challenges to install VSAT equipment, and operational challenges to keep the earth stations running in unmanned remote locations. Despite the challenges, the GCI has proven its worth in reliably collecting monitoring data and making such available to authorized users. It has also been useful to give scientists real-time access for controlling their remote monitoring stations.

  7. Utility terrestrial biodiversity issues

    NASA Astrophysics Data System (ADS)

    Breece, Gary Allen; Ward, Bobby J.

    1996-11-01

    Results from a survey of power utility biologists indicate that terrestrial biodiversity is considered a major issue by only a few utilities; however, a majority believe it may be a future issue. Over half of the respondents indicated that their company is involved in some management for biodiversity, and nearly all feel that it should be a goal for resource management. Only a few utilities are funding biodiversity research, but a majority felt more research was needed. Generally, larger utilities with extensive land holdings had greater opportunities and resources for biodiversity management. Biodiversity will most likely be a concern with transmission rights-of-way construction and maintenance, endangered species issues and general land resource management, including mining reclamation and hydro relicensing commitments. Over half of the companies surveyed have established voluntary partnerships with management groups, and biodiversity is a goal in nearly all the joint projects. Endangered species management and protection, prevention of forest fragmentation, wetland protection, and habitat creation and protection are the most common partnerships involving utility companies. Common management practices and unique approaches are presented, along with details of the survey.

  8. Utility terrestrial biodiversity issues

    SciTech Connect

    Breece, G.A. [Southern Company, Atlanta, GA (United States); Ward, B.J. [Carolina Power and Light Company, Raleigh, NC (United States)

    1996-11-01

    Results from a survey of power utility biologists indicate that terrestrial biodiversity is considered a major issued by only a few utilities; however, a majority believe it may be a future issue. Over half of the respondents indicated that their company is involved in some management for biodiversity, and nearly all feel that it should be a goal for resource management. Only a few utilities are funding biodiversity research, but a majority felt more research was needed. Generally, larger utilities with extensive land holdings had greater opportunities and resources for biodiversity management. Biodiversity will most likely be a concern with transmission rights-of-way construction and maintenance, endangered species issues and general land resource management, including mining reclamation and hydro relicensing commitments. Over half of the companies surveyed have established voluntary partnerships with management groups, and biodiversity is a goal in nearly all the joint projects. Endangered species management and protection, prevention of forest fragmentation, wetland protection, and habitat creation and protection are the most common partnerships involving utility companies. Common management practices and unique approaches are presented, along with details of the survey. 4 refs.

  9. GEOLogic: Terrestrial and Jovian Planets

    NSDL National Science Digital Library

    Laura Guertin

    In this two-part example, students are given clues about properties about the terrestrial and Jovian planets respectively and asked to match up the planet with the correct equatorial radius, mean orbital velocity, and period of rotation.

  10. Atmospheric Circulation of Terrestrial Exoplanets

    E-print Network

    Showman, Adam P; Merlis, Timothy M; Kaspi, Yohai

    2013-01-01

    The investigation of planets around other stars began with the study of gas giants, but is now extending to the discovery and characterization of super-Earths and terrestrial planets. Motivated by this observational tide, we survey the basic dynamical principles governing the atmospheric circulation of terrestrial exoplanets, and discuss the interaction of their circulation with the hydrological cycle and global-scale climate feedbacks. Terrestrial exoplanets occupy a wide range of physical and dynamical conditions, only a small fraction of which have yet been explored in detail. Our approach is to lay out the fundamental dynamical principles governing the atmospheric circulation on terrestrial planets--broadly defined--and show how they can provide a foundation for understanding the atmospheric behavior of these worlds. We first survey basic atmospheric dynamics, including the role of geostrophy, baroclinic instabilities, and jets in the strongly rotating regime (the "extratropics") and the role of the Hadle...

  11. 47 CFR 101.1307 - Permissible communications.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...SERVICES FIXED MICROWAVE SERVICES Multiple Address Systems General Provisions § 101.1307 Permissible communications. MAS users may engage in terrestrial point-to-point and point-to-multi-point fixed and limited mobile operations....

  12. 47 CFR 101.1307 - Permissible communications.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...SERVICES FIXED MICROWAVE SERVICES Multiple Address Systems General Provisions § 101.1307 Permissible communications. MAS users may engage in terrestrial point-to-point and point-to-multi-point fixed and limited mobile operations....

  13. 47 CFR 101.1307 - Permissible communications.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...SERVICES FIXED MICROWAVE SERVICES Multiple Address Systems General Provisions § 101.1307 Permissible communications. MAS users may engage in terrestrial point-to-point and point-to-multi-point fixed and limited mobile operations....

  14. Meeting the Needs of Rural Special Education in the Information Age: Using TI-IN Network's Interactive Satellite Based Educational Network.

    ERIC Educational Resources Information Center

    Pease, Pamela S.; Kitchen, Lillian

    The TI-IN Network is an interactive, satellite-based educational system offering a technological alternative to face-to-face classroom instruction. Developed through a cooperative venture between private enterprise and public education agencies, the TI-IN Network offers a total systems approach by providing the entire programming and hardware…

  15. Assessing satellite-based rainfall estimates in semi-arid watersheds using the USDA-ARS Walnut Gulch gauge network and TRMM-PR

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The rain gauge network associated with the U.S. Department of Agriculture, Agricultural Research Service Walnut Gulch Experimental Watershed (WGEW) in southeastern Arizona provides a unique opportunity for direct comparisons of in-situ measurements and satellite-based instantaneous rain-rate estimat...

  16. A Validation of Automated and Quality Controlled Satellite Based Fire Detection

    NASA Astrophysics Data System (ADS)

    Ruminski, M. G.; Hanna, J.

    2010-12-01

    The Satellite Analysis Branch (SAB) of NOAA/NESDIS performs a daily fire analysis for North America utilizing GOES, NOAA POES and MODIS satellite data. Automated fire detection algorithms are employed for each of the sensors. The automated detections are evaluated against the underlying satellite imagery by analysts, with detections that are believed to be false positives removed and missed fires added to the analysis. Previous validation of automated detections has typically utilized very high resolution satellite data, such as ASTER (30m), coincident in space and time with the sensor being validated. While this approach is useful for evaluating algorithm detection capability at a specific time for fires that are not obscured there is a high likelihood that it does not provide a comprehensive evaluation based on all fire occurrences for the day. Fires that occur before or after the satellite overpass would not be included and those that are obscured by clouds would also not be accounted for. These are important considerations in assessing climatology and for emission estimates. This study utilizes ground based reports from Florida, Montana, Idaho and South Carolina which have well established reporting and permitting procedures. These ground reports are primarily agricultural and prescribe burns for which permits are required. While it is possible that permits are obtained but the burn is not performed it is felt that this represents a small fraction of the number reported based on communication with permitting officials. Only the Probability Of Detection (POD) is computed. A positive detection occurs for satellite detections within 8km of a reported fire. This buffer is employed to allow for known satellite navigation errors. Determining false positive detects would not be reliable since there is no way of knowing with certainty that a detected fire did not actually occur at a location. It could easily be an unreported fire. Results for Florida based on daily reports from July 2008 through April 2010 show a POD of 7.8% out of 28000 reported fires for the GOES, 6.9% for the NOAA POES and 10.1% for the MODIS algorithms. Preliminary results indicate that similar POD values are exhibited for Montana, Idaho and South Carolina. Since multiple sensors detect many of the reported fires, the POD for all algorithms is less than the sum of the individual sensors. The POD increases as the size of the reported fire increases but reaches an upper limit of around 70%. The primary reason for an upper limit of POD, even with very large fires of 1000+ acres, is the presence of extensive cloud cover which obscures the fire from the sensor's view. These results indicate that using multiple sensors is essential for optimal fire detection and that augmentation by a trained analyst improves the results even further. With similar results seen for different states in different parts of the country this suggests sensor algorithm performance is not radically different for various ecosystems and climate regimes. The low detection rate is significantly skewed toward smaller fires with the majority of undetected fires being 25 acres or less in size. However, the cumulative emissions from large numbers of undetected small fires can be regionally significant and need to be accounted for in emission models/estimates.

  17. A Series of Improved Goddard Satellite-based Surface Turbulent Fluxes (GSSTF) Datasets and the Associated Data Uncertainties

    NASA Astrophysics Data System (ADS)

    Shie, C.; Chiu, L.; Gao, S.

    2012-12-01

    Accurate ocean surface turbulent flux measurements are crucial to understanding the global water and energy cycle changes. As a major component of the global oceanic fresh water flux, the oceanic evaporation is particularly useful for predicting oceanic circulation and transport. Remote sensing is a valuable tool for global monitoring of these flux measurements. The GSSTF algorithm was thus developed and applied to remote sensing research and applications. As one of the earliest GSSTF datasets, GSSTF2 had been widely used by the scientific community for global energy and water cycle research since its official release in 2001. However, the original GSSTF project halted indefinitely after the GSSTF2 release. Thanks to the NASA/Making Earth System data records for Use in Research Environments (MEaSUREs) Program, the GSSTF project has been luckily awarded and revived in May 2008. In these past four years, three subsequently developed and improved datasets, (1) GSSTF2b (global 1°x1°; July 1987-December 2008) using upgraded and improved input data such as the Special Sensor Microwave Imagers (SSM/I) V6 brightness temperature (TB) and the NCEP-DOE Reanalysis II SST, (2) GSSTF2c (global 1°x1°; July 1987-December 2008) using the lately corrected TB's by removing artificial trends due to the temporal variations (decreasing) of Earth incidence angle of individual SSM/I satellites, and (3) GSSTF3 (global 0.25°x0.25°; January 1998-December 2008 so far) with a finer spatial resolution and using an updated method for retrieving surface specific humidity (Qa), have therefore been produced and distributed in October 2010, October 2011, and June 2012, respectively. By improving the input data (particularly, the SSM/I Tb's) and the model/algorithm (i.e., for the Qa retrieval), we have seen systematical improvements, particularly in the globally averaged latent heat flux (LHF), from GSSTF2b to GSSTF2c, then GSSTF3. Details of the data improvements will be further elaborated at the meeting, along with the "Rice Cooker Theory": the equal importance of the quality of model/algorithm ("Rice Cooker") and the quality of input parameters ("Rice") in retrieving the satellite-based air-sea turbulent fluxes ("Cooked Rice"!). Last and but not least, we will also present the uncertainty of the fluxes, particularly in the globally averaged LHF, at the meeting. The uncertainty analysis involves a total of six datasets that include the three aforementioned GSSTF datasets, and three other available flux datasets produced by peer scientists, i.e., the Japanese Ocean Flux datasets with Use of Remote Sensing Observations version 2 (J-OFURO2; satellite-based); the Hamburg Ocean Atmosphere Parameters and Fluxes from Satellite Data version 3 (HOAPS-3; satellite-based); and the Objectively Analyzed air-sea Fluxes (OAFlux; combined satellite and reanalysis).

  18. Relation between Ocean SST Dipoles and Downwind Continental Croplands Assessed for Early Management Using Satellite-based Photosynthesis Models

    NASA Astrophysics Data System (ADS)

    Kaneko, Daijiro

    2015-04-01

    Crop-monitoring systems with the unit of carbon-dioxide sequestration for environmental issues related to climate adaptation to global warming have been improved using satellite-based photosynthesis and meteorological conditions. Early management of crop status is desirable for grain production, stockbreeding, and bio-energy providing that the seasonal climate forecasting is sufficiently accurate. Incorrect seasonal forecasting of crop production can damage global social activities if the recognized conditions are unsatisfied. One cause of poor forecasting related to the atmospheric dynamics at the Earth surface, which reflect the energy budget through land surface, especially the oceans and atmosphere. Recognition of the relation between SST anomalies (e.g. ENSO, Atlantic Niño, Indian dipoles, and Ningaloo Niño) and crop production, as expressed precisely by photosynthesis or the sequestrated-carbon rate, is necessary to elucidate the mechanisms related to poor production. Solar radiation, surface air temperature, and water stress all directly affect grain vegetation photosynthesis. All affect stomata opening, which is related to the water balance or definition by the ratio of the Penman potential evaporation and actual transpiration. Regarding stomata, present data and reanalysis data give overestimated values of stomata opening because they are extended from wet models in forests rather than semi-arid regions commonly associated with wheat, maize, and soybean. This study applies a complementary model based on energy conservation for semi-arid zones instead of the conventional Penman-Monteith method. Partitioning of the integrated Net PSN enables precise estimation of crop yields by modifying the semi-closed stomata opening. Partitioning predicts production more accurately using the cropland distribution already classified using satellite data. Seasonal crop forecasting should include near-real-time monitoring using satellite-based process crop models to avoid social difficulties that can derive from uncertain seasonal predictions produced from long-term forecasting. Acknowledgement The author appreciates scientific discussions held with the application team of seasonal prediction at the Japan Agency for Marine-Earth Science and Technology. Key words: crop production, monitoring, forecasting, SST anomaly, remote sensing

  19. Carbon Sequestration in Terrestrial Ecosystems

    NASA Astrophysics Data System (ADS)

    Jacobs, G. K.; Post, W. M.; Jastrow, J. D.; Izaurralde, R. C.

    2002-05-01

    CSiTE, the Department of Energy's research consortium performs fundamental research in support of new methods to enhance carbon sequestration in terrestrial ecosystems in an environmentally acceptable manner. The goal of CSiTE is to discover and characterize links between critical pathways and mechanisms across scales from the molecular to the landscape for creating larger, longer-lasting carbon pools in terrestrial ecosystems. This paper will present results relevant to increasing the biophysical potential of terrestrial C sequestration, but in addition will illustrate the importance of an integrative analysis in assessing this technological option (as well as all sequestration options). Our integrative approach involves six steps: (1) Identify promising technologies, (2) Understand controls on basic mechanisms at the site scale, (3) Perform sensitivity analyses over the range of applicable conditions (model, lab or field experiments), (4) Full C and greenhouse gas accounting, (5) Environmental impacts, and (6) Economic analysis including rate of adoption and cost tradeoffs. Many estimates of the potential contributions of sequestration by terrestrial ecosystems to the control of rising atmospheric carbon dioxide concentration have been rather modest. Indeed, there are many uncertainties and ancillary issues (permanence, land availability, water supply, etc) that must be considered. However, terrestrial ecosystems have not been viewed to-date as a "technology" to be implemented. Rather, the emphasis has been on the promotion of practices that are likely to be implemented for other benefits. It may be possible to use the attributes of terrestrial ecosystems to a greater extent in sequestering carbon. In this paper, we will discuss how a technology view of terrestrial ecosystems may alter the estimated contributions. Examples to be addressed include changing land use, shifting agricultural methods, manipulating soil properties, and altering soil microbial systems.

  20. A satellite-based biosphere parameterization for net ecosystem CO2 exchange: Vegetation Photosynthesis and Respiration Model (VPRM)

    NASA Astrophysics Data System (ADS)

    Mahadevan, Pathmathevan; Wofsy, Steven C.; Matross, Daniel M.; Xiao, Xiangming; Dunn, Allison L.; Lin, John C.; Gerbig, Christoph; Munger, J. William; Chow, Victoria Y.; Gottlieb, Elaine W.

    2008-06-01

    We present the Vegetation Photosynthesis and Respiration Model (VPRM), a satellite-based assimilation scheme that estimates hourly values of Net Ecosystem Exchange (NEE) of CO2 for 12 North American biomes using the Enhanced Vegetation Index (EVI) and Land Surface Water Index (LSWI), derived from reflectance data of the Moderate Resolution Imaging Spectroradiometer (MODIS), plus high-resolution data for sunlight and air temperature. The motivation is to provide reliable, fine-grained first-guess fields of surface CO2 fluxes for application in inverse models at continental and smaller scales. An extremely simple mathematical structure, with minimal numbers of parameters, facilitates optimization using in situ data, with finesse provided by maximal infusion of observed NEE and environmental data from networks of eddy covariance towers across North America (AmeriFlux and Fluxnet Canada). Cross validation showed that the VPRM has strong prediction ability for hourly to monthly timescales for sites with similar vegetation. The VPRM also provides consistent partitioning of NEE into Gross Ecosystem Exchange (GEE, the light-dependent part of NEE) and ecosystem respiration (R, the light-independent part), half-saturation irradiance of ecosystem photosynthesis, and annual sum of NEE at all eddy flux sites for which it is optimized. The capability to provide reliable patterns of surface flux for fine-scale inversions is presently limited by the number of vegetation classes for which NEE can be constrained by the current network of eddy flux sites and by the accuracy of MODIS data and data for sunlight.

  1. Regression imputation with ground air temperature for the satellite-based lake and reservoir temperature database in Japan

    NASA Astrophysics Data System (ADS)

    Tonooka, Hideyuki

    2012-10-01

    Water temperature monitoring for inland water bodies like lakes and reservoirs is important in the aspects of biodiversity conservation, and global warming monitoring. However, most of inland water bodies except for a few large water bodies have not fully or never been monitored on water temperature, partly because in-situ temperature measurements are not easy for small water bodies which are widely scattered and variously managed by individuals, companies, governments etc. Thus, the satellite-based lake and reservoir temperature database in Japan (SatLARTD-J) has been developed since 2009. At present, the database contains surface temperature data for 934 water bodies which were retrieved from thermal infrared (TIR) images of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument onboard NASA's Terra satellite, but its temporal resolution is only four times per year in average. In order to improve this, the author demonstrates regression imputation for SatLARTD-J using ground air temperature data provided from the Automated Meteorological Data Acquisition System (AMeDAS) operated by Japan Meteorological Agency. The validation study using in-situ data from two Japanese lakes indicates that an expected imputation error will be about 2 K.

  2. Strategic system development toward biofuel, desertification, and crop production monitoring in continental scales using satellite-based photosynthesis models

    NASA Astrophysics Data System (ADS)

    Kaneko, Daijiro

    2013-10-01

    The author regards fundamental root functions as underpinning photosynthesis activities by vegetation and as affecting environmental issues, grain production, and desertification. This paper describes the present development of monitoring and near real-time forecasting of environmental projects and crop production by approaching established operational monitoring step-by-step. The author has been developing a thematic monitoring structure (named RSEM system) which stands on satellite-based photosynthesis models over several continents for operational supports in environmental fields mentioned above. Validation methods stand not on FLUXNET but on carbon partitioning validation (CPV). The models demand continuing parameterization. The entire frame system has been built using Reanalysis meteorological data, but model accuracy remains insufficient except for that of paddy rice. The author shall accomplish the system that incorporates global environmental forces. Regarding crop production applications, industrialization in developing countries achieved through direct investment by economically developed nations raises their income, resulting in increased food demand. Last year, China began to import rice as it had in the past with grains of maize, wheat, and soybeans. Important agro-potential countries make efforts to cultivate new crop lands in South America, Africa, and Eastern Europe. Trends toward less food sustainability and stability are continuing, with exacerbation by rapid social and climate changes. Operational monitoring of carbon sequestration by herbaceous and bore plants converges with efforts at bio-energy, crop production monitoring, and socio-environmental projects such as CDM A/R, combating desertification, and bio-diversity.

  3. Satellite-based model detection of recent climate-driven changes in northern high-latitude vegetation productivity

    Microsoft Academic Search

    Ke Zhang; John S. Kimball; E. H. Hogg; Maosheng Zhao; Walter C. Oechel; John J. Cassano; Steven W. Running

    2008-01-01

    We applied a satellite remote sensing based production efficiency model (PEM) using an integrated AVHRR and MODIS FPAR\\/LAI time series with a regionally corrected NCEP\\/NCAR reanalysis daily surface meteorology and NASA\\/GEWEX Surface Radiation Budget shortwave solar radiation inputs to assess annual terrestrial net primary productivity (NPP) for the pan-Arctic basin and Alaska from 1983 to 2005. Our results show that

  4. Utilization of the terrestrial cyanobacteria

    NASA Astrophysics Data System (ADS)

    Katoh, Hiroshi; Tomita-Yokotani, Kaori; Furukawa, Jun; Kimura, Shunta; Yokoshima, Mika; Yamaguchi, Yuji; Takenaka, Hiroyuki

    The terrestrial, N _{2}-fixing cyanobacterium, Nostoc commune has expected to utilize for agriculture, food and terraforming cause of its extracellular polysaccharide, desiccation tolerance and nitrogen fixation. Previously, the first author indicated that desiccation related genes were analyzed and the suggested that the genes were related to nitrogen fixation and metabolisms. In this report, we suggest possibility of agriculture, using the cyanobacterium. Further, we also found radioactive compounds accumulated N. commune (cyanobacterium) in Fukushima, Japan after nuclear accident. Thus, it is investigated to decontaminate radioactive compounds from the surface soil by the cyanobacterium and showed to accumulate radioactive compounds using the cyanobacterium. We will discuss utilization of terrestrial cyanobacteria under closed environment. Keyword: Desiccation, terrestrial cyanobacteria, bioremediation, agriculture

  5. Terrestrial ecosystems and climatic change

    SciTech Connect

    Emanuel, W.R. (Oak Ridge National Lab., TN (USA)); Schimel, D.S. (Colorado State Univ., Fort Collins, CO (USA). Natural Resources Ecology Lab.)

    1990-01-01

    The structure and function of terrestrial ecosystems depend on climate, and in turn, ecosystems influence atmospheric composition and climate. A comprehensive, global model of terrestrial ecosystem dynamics is needed. A hierarchical approach appears advisable given currently available concepts, data, and formalisms. The organization of models can be based on the temporal scales involved. A rapidly responding model describes the processes associated with photosynthesis, including carbon, moisture, and heat exchange with the atmosphere. An intermediate model handles subannual variations that are closely associated with allocation and seasonal changes in productivity and decomposition. A slow response model describes plant growth and succession with associated element cycling over decades and centuries. These three levels of terrestrial models are linked through common specifications of environmental conditions and constrain each other. 58 refs.

  6. A satellite system for land-mobile communications in Europe

    NASA Astrophysics Data System (ADS)

    Bartholome, P.; Rogard, R.

    1988-05-01

    There exists a great unsatisified demand for land mobile communications in Europe, particularly in sectors of business activity such as the road transport industry. This demand could best be satisfied by means of satellite-based private networks providing voice and data communications in a hub configuration. The potential market is estimated to encompass several hundred thousand road vehicles and the transmission capacity required would be several thousand channels. ESA is currently demonstrating the potential of satellite communications for this type of application, using a system called PRODAT. System studies are being performed with the aim of defining the architecture of a regional satellite system for Europe.

  7. Satellite-Based Videoconferencing.

    ERIC Educational Resources Information Center

    Distance Education Report, 1997

    1997-01-01

    Educators can broadcast videoconferences to students in different parts of the world at an affordable cost using geostationary satellites. Describes the design and presentation of videoconferences and outlines steps in their development: budgeting, scheduling, selecting presenters and moderators, choosing production and telecast facilities,…

  8. Internal errors of ground-based terrestrial earthshine measurements in 5 colour bands.

    NASA Astrophysics Data System (ADS)

    Thejll, Peter; Gleisner, Hans; Flynn, Chris

    2015-04-01

    Measurements of earthshine intensity could be an important complement to satellite-based observations of terrestrial visual and near-IR radiative budgets because they are independent and relatively inexpensive to obtain and also offer different potentials for long-term bias stability. Using ground-based photometric instruments, the Moon is imaged several times a night through a range of photometric filters, and the ratio of the intensities of the dark (Earth-lit) and bright (Sun-lit) sides is calculated - this ratio is proportional to terrestrial albedo. Using forward modelling of the expected ratio, given assumptions about reflectance, single-scattering albedo, and light-scattering processes it is possible to deduce the terrestrial albedo. In this poster we present multicolour photometric results from observations on 10 nights, obtained at the NOAA observatory on Mauna Loa, Hawaii, in 2011. The Moon had different phases on these nights and we discuss in detail the behaviour of internal errors as a function of phase. The internal error is dependent on the photon-statistics of the images obtained and its magnitude is investigated by use of bootstrapping with replacement of observations. Results indicate that standard Johnson B and V band equivalent Lambert albedos can be obtained with precisions (1 standard deviation) in the 0.1 to 1% range for phases between 40 and 90 degrees. For longer wavelengths, corresponding to broader bands on either side of the 'Vegetation edge' at 750nm, we see larger variability in the albedo determinations and discuss whether these are due to atmospheric conditions or represent fast, intrinsic terrestrial albedo variations. The accuracy of these results, however, appear to depend on method choices, in particular the choice of lunar reflectance model -- this 'external error' will be investigated in future analyses.

  9. Real-time Global Flood Estimation using Satellite-based Precipitation and a Coupled Land Surface and Routing Model

    SciTech Connect

    Wu, Huan; Adler, Robert F.; Tian, Yudong; Huffman, George; Li, Hongyi; Wang, Jianjian

    2014-04-09

    A community land surface model, the Variable Infiltration Capacity (VIC) model, is coupled with a newly developed hierarchical dominant river tracing-based runoff-routing model to form the Dominant river tracing-Routing Integrated with VIC Environment (DRIVE) model system, which serves as the new core of the real-time Global Flood Monitoring System (GFMS). The GFMS uses real-time satellite-based precipitation to derive flood-monitoring parameters for the latitude-band 50{degree sign}N-50{degree sign}S at relatively high spatial (~12km) and temporal (3-hourly) resolution. Examples of model results for recent flood events are computed using the real-time GFMS (http://flood.umd.edu). To evaluate the accuracy of the new GFMS, the DRIVE model is run retrospectively for 15 years using both research-quality and real-time satellite precipitation products. Statistical results are slightly better for the research-quality input and significantly better for longer duration events (three-day events vs. one-day events). Basins with fewer dams tend to provide lower false alarm ratios. For events longer than three days in areas with few dams, the probability of detection is ~0.9 and the false alarm ratio is ~0.6. In general, these statistical results are better than those of the previous system. Streamflow was evaluated at 1,121 river gauges across the quasi-global domain. Validation using real-time precipitation across the tropics (30ºS-30ºN) gives positive daily Nash-Sutcliffe Coef?cients for 107 out of 375 (28%) stations with a mean of 0.19 and 51% of the same gauges at monthly scale with a mean of 0.33. There were poorer results in higher latitudes, probably due to larger errors in the satellite precipitation input.

  10. AQA-PM: Extension of the Air-Quality model for Austria with satellite based Particulate Matter estimates

    NASA Astrophysics Data System (ADS)

    Hirtl, M.; Mantovani, S.; Krüger, B. C.; Triebnig, G.

    2012-04-01

    Air quality is a key element for the well-being and quality of life of European citizens. Air pollution measurements and modeling tools are essential for assessment of air quality according to EU legislation. The responsibilities of ZAMG as the national weather service of Austria include the support of the federal states and the public in questions connected to the protection of the environment in the frame of advisory and counseling services as well as expert opinions. The Air Quality model for Austria (AQA) is operated at ZAMG in cooperation with the University of Natural Resources and Applied Life Sciences in Vienna (BOKU) by order of the regional governments since 2005. AQA conducts daily forecasts of gaseous and particulate (PM10) air pollutants over Austria. In the frame of the project AQA-PM (funded by FFG), satellite measurements of the Aerosol Optical Thickness (AOT) and ground-based PM10-measurements are combined to highly-resolved initial fields using assimilation techniques. It is expected that the assimilation of satellite measurements will significantly improve the quality of AQA. Currently no observations are considered in the modeling system. At the current stage of the project, different datasets have been collected (ground measurements, satellite measurements, fine resolved regional emission inventories) and are analyzed and prepared for further processing. This contribution gives an overview of the project working plan and the upcoming developments. The goal of this project is to improve the PM10-forecasts for Austria with the integration of satellite based measurements and to provide a comprehensive product-platform.

  11. AQA-PM: Extension of the Air-Quality Model For Austria with Satellite based Particulate Matter Estimates

    NASA Astrophysics Data System (ADS)

    Hirtl, Marcus; Mantovani, Simone; Krüger, Bernd C.; Triebnig, Gerhard; Flandorfer, Claudia

    2013-04-01

    Air quality is a key element for the well-being and quality of life of European citizens. Air pollution measurements and modeling tools are essential for assessment of air quality according to EU legislation. The responsibilities of ZAMG as the national weather service of Austria include the support of the federal states and the public in questions connected to the protection of the environment in the frame of advisory and counseling services as well as expert opinions. The Air Quality model for Austria (AQA) is operated at ZAMG in cooperation with the University of Natural Resources and Life Sciences in Vienna (BOKU) by order of the regional governments since 2005. AQA conducts daily forecasts of gaseous and particulate (PM10) air pollutants over Austria. In the frame of the project AQA-PM (funded by FFG), satellite measurements of the Aerosol Optical Thickness (AOT) and ground-based PM10-measurements are combined to highly-resolved initial fields using regression- and assimilation techniques. For the model simulations WRF/Chem is used with a resolution of 3 km over the alpine region. Interfaces have been developed to account for the different measurements as input data. The available local emission inventories provided by the different Austrian regional governments were harmonized and used for the model simulations. An episode in February 2010 is chosen for the model evaluation. During that month exceedances of PM10-thresholds occurred at many measurement stations of the Austrian network. Different model runs (only model/only ground stations assimilated/satellite and ground stations assimilated) are compared to the respective measurements. The goal of this project is to improve the PM10-forecasts for Austria with the integration of satellite based measurements and to provide a comprehensive product-platform.

  12. Satellite-based climatology of low-level continental clouds in southern West Africa during the summer monsoon season

    NASA Astrophysics Data System (ADS)

    Linden, Roderick; Fink, Andreas H.; Redl, Robert

    2015-02-01

    Synoptic observations and various satellite products have been utilized for computing climatologies of low-level stratus over southern West Africa for the wet monsoon seasons July-September of 2006-2011. Previous studies found inconsistencies between satellite cloud products; climate models often fail to reproduce the extensive stratus decks. Therefore, a better observational reference and an understanding of its limitations are urgently needed to better validate models. Most detailed information of the spatiotemporal characteristics of low-level clouds was obtained from two Meteosat Second Generation (MSG) satellite-based data sets. However, CALIPSO and CloudSat cross sections of cloud occurrence frequency suggest that both MSG products underestimate the low-level cloudiness over Nigeria due to shielding by abundant upper level and midlevel clouds and reveal that the stratus is lower over the continent than over the ocean. The Terra Multiangle Imaging Spectroradiometer product appears to overestimate the morning extent of low-level clouds. The climatology presented here shows that the zone of abundant low-level stratiform clouds is at its diurnal minimum south of 6-7°N around sunset (~1800 UTC). Thereafter, it starts to spread inland and reaches its maximum northward extent of 10-11°N between 0900 and 1000 UTC. The maximum affected area is approximately 800,000 km2. After about 1000 UTC, the northern boundary gets fragmented due to the breakup of stratus decks into fair-weather cumuli. The stratus is most frequent around Cape Palmas, over Ivory Coast, and at the windward sides of the Mampong Range (Ghana) and Oshogbo Hills (Nigeria).

  13. Mobile small aperture satellite terminals for military communications

    Microsoft Academic Search

    Vijitha Weerackody; Lino Gonzalez

    2007-01-01

    The United States Army is currently developing a satellite-based network-centric waveform. Mobile terminals that are small and compact are highly desirable for the military. This article gives an overview of the technical challenges and performance issues when mobile small aperture satellite terminals are connected to a network- centric communication system. The specific issues addressed are regulatory limits on off-axis emissions,

  14. CARBON DIOXIDE SEQUESTRATION IN TERRESTRIAL ECOSYSTEMS

    EPA Science Inventory

    The terrestrial biosphere plays a prominent role in the global carbon (C) cycle. errestrial ecosystems are currently accumulating C and it appears feasible to manage existing terrestrial (forest, agronomic, desert) ecosystems to maintain or increase C storage. orest ecosystems ca...

  15. Terrestrial Behavior of Ateles spp

    Microsoft Academic Search

    Christina J. Campbell; Filippo Aureli; Colin A. Chapman; Gabriel Ramos-Fernández; Kim Matthews; Sabrina E. Russo; Scott Suarez; Laura Vick

    2005-01-01

    Spider monkeys (Ateles spp.) are well known for their highly arboreal lifestyle, spending much of their time in the highest levels of the canopy and rarely venturing to the ground. To investigate terrestriality by Ateles and to illuminate the conditions under which spider monkeys venture to the ground, we analyzed ad libitum data from 5 study sites, covering 2 species

  16. Carbon dioxide and terrestrial ecosystems

    Microsoft Academic Search

    G. W. Koch; H. A. Mooney

    1996-01-01

    This book is a summary of the current research which addresses the effects of elevated carbon dioxide on terrestrial ecosystems and an identification of significant unresolved issues. Chapters address the carbon dioxide effects on trees and forests, unmanaged herbaceous ecosystems, and crops. Included are experimental studies, conceptual models, general mathematical models, dynamic simulation models.

  17. Ionospheres of the terrestrial planets

    Microsoft Academic Search

    R. W. Schunk; A. F. Nagy

    1980-01-01

    The theory and observations relating to the ionospheres of the terrestrial planets Venus, the earth and Mars are reviewed. Emphasis is placed on comparing the basic differences and similarities between the planetary ionospheres. The review covers the plasma and electric-magnetic field environments that surround the planets, the theory leading to the creation and transport of ionization in the ionspheres, the

  18. Furostanol saponins from Tribulus terrestris

    Microsoft Academic Search

    E De Combarieu; N Fuzzati; M Lovati; E Mercalli

    2003-01-01

    An HPLC-ELSD-ESI-MS method has been developed for the analysis of the steroidal saponins in the aerial parts of Tribulus terrestris. Protodioscin, a new saponin (5,6-dihydroprotodioscin, neoprotodioscin) and their respective sulfates were detected. The structure of the new compound was elucidated on the basis of NMR and ESI-MS spectral analysis.

  19. NEON Airborne Remote Sensing of Terrestrial Ecosystems

    NASA Astrophysics Data System (ADS)

    Kampe, T. U.; Leisso, N.; Krause, K.; Karpowicz, B. M.

    2012-12-01

    The National Ecological Observatory Network (NEON) is the continental-scale research platform that will collect information on ecosystems across the United States to advance our understanding and ability to forecast environmental change at the continental scale. One of NEON's observing systems, the Airborne Observation Platform (AOP), will fly an instrument suite consisting of a high-fidelity visible-to-shortwave infrared imaging spectrometer, a full waveform small footprint LiDAR, and a high-resolution digital camera on a low-altitude aircraft platform. NEON AOP is focused on acquiring data on several terrestrial Essential Climate Variables including bioclimate, biodiversity, biogeochemistry, and land use products. These variables are collected throughout a network of 60 sites across the Continental United States, Alaska, Hawaii and Puerto Rico via ground-based and airborne measurements. Airborne remote sensing plays a critical role by providing measurements at the scale of individual shrubs and larger plants over hundreds of square kilometers. The NEON AOP plays the role of bridging the spatial scales from that of individual organisms and stands to the scale of satellite-based remote sensing. NEON is building 3 airborne systems to facilitate the routine coverage of NEON sites and provide the capacity to respond to investigator requests for specific projects. The first NEON imaging spectrometer, a next-generation VSWIR instrument, was recently delivered to NEON by JPL. This instrument has been integrated with a small-footprint waveform LiDAR on the first NEON airborne platform (AOP-1). A series of AOP-1 test flights were conducted during the first year of NEON's construction phase. The goal of these flights was to test out instrument functionality and performance, exercise remote sensing collection protocols, and provide provisional data for algorithm and data product validation. These test flights focused the following questions: What is the optimal remote sensing data collection protocol to meet NEON science requirements? How do aircraft altitude, spatial sampling, spatial resolution, and LiDAR instrument configuration affect data retrievals? What are appropriate algorithms to derive ECVs from AOP data? What methodology should be followed to validate AOP remote sensing products and how should ground truth data be collected? Early test flights were focused on radiometric and geometric calibration as well as processing from raw data to Level-1 products. Subsequent flights were conducted focusing on collecting vegetation chemistry and structure measurements. These test flights that were conducted during 2012 have proved to be extremely valuable for verifying instrument functionality and performance, exercising remote sensing collection protocols, and providing data for algorithm and science product validation. Results from these early flights are presented, including the radiometric and geometric calibration of the AOP instruments. These 2012 flight campaigns are just the first of a series of test flights that will take place over the next several years as part of the NEON observatory construction. Lessons learned from these early campaigns will inform both airborne and ground data collection methodologies for future campaigns as well as guide the AOP sampling strategy before NEON enters full science operations.

  20. Terrestrial biogeochemical feedbacks in the climate system

    Microsoft Academic Search

    A. Arneth; S. P. Harrison; S. Zaehle; K. Tsigaridis; S. Menon; P. J. Bartlein; J. Feichter; A. Korhola; M. Kulmala; D. O'Donnell; G. Schurgers; S. Sorvari; T. Vesala

    2010-01-01

    The terrestrial biosphere is a key regulator of atmospheric chemistry and climate. During past periods of climate change, vegetation cover and interactions between the terrestrial biosphere and atmosphere changed within decades. Modern observations show a similar responsiveness of terrestrial biogeochemistry to anthropogenically forced climate change and air pollution. Although interactions between the carbon cycle and climate have been a central

  1. Commercial aerospace and terrestrial applications of nickel-hydrogen batteries

    SciTech Connect

    Caldwell, D.B.; Coates, D.K.; Fox, C.L.; Miller, L.E. [Advanced Systems Operation, Eagle-Picher Industries, Inc., Joplin, Missouri 64801 (United States)

    1996-03-01

    The nickel-hydrogen battery system, used extensively in the aerospace industry to supply electrical power to earth-orbital satellites for communications, observation, and military applications, is being developed for commercial, terrestrial applications. Low-cost components, electrodes, cell designs, and battery designs are currently being tested. Catalytic hydrogen electrodes have been developed which are compatible with commercial nickel battery cost. Prismatic and spiral-wound cell designs have been built and tested. Common pressure vessel and dependent pressure vessel battery designs are also being evaluated. The nickel-hydrogen battery offers potential cycle life unequaled by any other battery system. This makes the battery ideal for many commercial and terrestrial energy storage applications such as telecommunication, remote stand-alone power systems, utility load-leveling, and other applications which require long life and a truly maintenance-free and abuse-tolerant battery system. {copyright} {ital 1996 American Institute of Physics.}

  2. Commercial aerospace and terrestrial applications of nickel-hydrogen batteries

    NASA Astrophysics Data System (ADS)

    Caldwell, Dwight B.; Coates, Dwaine K.; Fox, Chris L.; Miller, Lee E.

    1996-03-01

    The nickel-hydrogen battery system, used extensively in the aerospace industry to supply electrical power to earth-orbital satellites for communications, observation, and military applications, is being developed for commercial, terrestrial applications. Low-cost components, electrodes, cell designs, and battery designs are currently being tested. Catalytic hydrogen electrodes have been developed which are compatible with commercial nickel battery cost. Prismatic and spiral-wound cell designs have been built and tested. Common pressure vessel and dependent pressure vessel battery designs are also being evaluated. The nickel-hydrogen battery offers potential cycle life unequaled by any other battery system. This makes the battery ideal for many commercial and terrestrial energy storage applications such as telecommunication, remote stand-alone power systems, utility load-leveling, and other applications which require long life and a truly maintenance-free and abuse-tolerant battery system.

  3. Study terrestrial applications of solar cell powered systems

    NASA Technical Reports Server (NTRS)

    Ravin, J. W.

    1973-01-01

    Terrestrial applications of solar cells and design systems are considered for those applications that show the most promise for becoming practical and accepted by users within the next five years. The study includes the definition, categorization, evaluation and screening of the most attractive potential terrestrial applications for solar cells. Potential markets are initially grouped and categorized in a general sense and are weighted in priority by their business volume, present and future. From a categorized list including marine, transportation, security, communication, meteorological and others, 66 potential solar cell applications have been cataloged. A methodology was formulated to include the criteria for evaluation and screening. The evaluation process covers all parts and components of the complete system required for each application and gives consideration to all factors, such as engineering, economic, production, marketing and other factors that may have an influence on the acceptance of the system.

  4. Digital communications: Satellite\\/earth station engineering

    Microsoft Academic Search

    K. Feher

    1983-01-01

    The analysis and design of the elements of modern satellite communications systems are considered. Illustrative earth station and satellite communications subsystems are first introduced, and link budget calculations are discussed. Signal processing and multiplexing techniques used in terrestrial interface subsystems are described, as are baseband transmission systems principles and design techniques. The principles, performance analysis, and design tools of power-efficient

  5. Adaptive OFDMA for Downlink Underwater Acoustic Communications

    E-print Network

    Zhou, Shengli

    --Underwater acoustic communications, OFDMA, subcarrier allocation, power and bit loading I. INTRODUCTION Multicarrier is presented to jointly assign the data subcarriers to different users and allocate the power and bits on each. There are extensive investigations of multiuser OFDM in broadband terrestrial communication systems, e.g., [4

  6. Estimating Evapotranspiration Using an Observation Based Terrestrial Water Budget

    NASA Technical Reports Server (NTRS)

    Rodell, Matthew; McWilliams, Eric B.; Famiglietti, James S.; Beaudoing, Hiroko K.; Nigro, Joseph

    2011-01-01

    Evapotranspiration (ET) is difficult to measure at the scales of climate models and climate variability. While satellite retrieval algorithms do exist, their accuracy is limited by the sparseness of in situ observations available for calibration and validation, which themselves may be unrepresentative of 500m and larger scale satellite footprints and grid pixels. Here, we use a combination of satellite and ground-based observations to close the water budgets of seven continental scale river basins (Mackenzie, Fraser, Nelson, Mississippi, Tocantins, Danube, and Ubangi), estimating mean ET as a residual. For any river basin, ET must equal total precipitation minus net runoff minus the change in total terrestrial water storage (TWS), in order for mass to be conserved. We make use of precipitation from two global observation-based products, archived runoff data, and TWS changes from the Gravity Recovery and Climate Experiment satellite mission. We demonstrate that while uncertainty in the water budget-based estimates of monthly ET is often too large for those estimates to be useful, the uncertainty in the mean annual cycle is small enough that it is practical for evaluating other ET products. Here, we evaluate five land surface model simulations, two operational atmospheric analyses, and a recent global reanalysis product based on our results. An important outcome is that the water budget-based ET time series in two tropical river basins, one in Brazil and the other in central Africa, exhibit a weak annual cycle, which may help to resolve debate about the strength of the annual cycle of ET in such regions and how ET is constrained throughout the year. The methods described will be useful for water and energy budget studies, weather and climate model assessments, and satellite-based ET retrieval optimization.

  7. Assessing regional crop water demand using a satellite-based combination equation with a land surface temperature component

    NASA Astrophysics Data System (ADS)

    Moyano, Maria Carmen; Garcia, Monica; Tornos, Lucia; Recuero, Laura; Palacios-Orueta, Alicia; Juana, Luis

    2015-04-01

    Quantification of daily evapotranspiration at regional levels is fundamental for improving agricultural and hydrological management, especially in water-scarce and climatic change vulnerable regions, like the Mediterranean basin. Regional estimates of daily crop evapotranspiration (ET) have been historically based on combination equations, such as Penman-Monteith or Priestley-Taylor, forced with weather-data inputs. However, the requirements for long term in-situ data, limit the application of such traditional approaches and algorithms using satellite-data without field calibrations bridge this gap by estimating long-term ET at the pixel level from local to global scales. Land surface temperature is a key variable tracking land surface moisture status. However, it has not been included in satellite ET approaches based on combination equations. In this study, a land surface temperature component was used to estimate soil surface conductance based on an apparent thermal inertia index. A process-based model was applied to estimate surface energy fluxes including daily ET based on a modified version of the Priestley-Taylor Jet Propulsion Laboratory (PT-JPL) model at 1km pixel resolution during a chrono-sequence spanning for more than a decade (2002-2013). The thermal-PT-JPL model was forced with vegetation, albedo, reflectance and temperature products from the Moderate-resolution Imaging Spectroradiometer (MODIS) from both Aqua and Terra satellites. The study region, B-XII Irrigation District of the Lower Guadalquivir, is one of the largest irrigated areas in Spain but it has scarce in-situ micrometeorological or eddy covariance data. The final aim of this study is to evaluate the thermal version of PT-JPL model versus a lumped hydrological model to assess crop evapotranspiration deficits and long-term water consumption trends in the area. The results showed that the thermal-PT-JPL model is a suitable and simple tool requiring only air temperature and incoming solar radiation apart from standard satellites-products freely available. Our results show that in comparison with the hydrological model conceptual rainfall-runoff model, requiring several meteorological and in-situ data to quantify irrigation, the satellite-based model presents a great advantage for regionalization of ET.

  8. Satellite-based remote sensing of cirrus clouds: hyperspectral radiative transfer modeling, analysis of uncertainties in in-situ cloud extinction measurements and intercomparison of cirrus retrievals from a-train instruments 

    E-print Network

    Zhang, Zhibo

    2009-05-15

    This dissertation consists of three parts, each devoted to a particular issue of significant importance for satellite-based remote sensing of cirrus clouds. In the first part, we develop and present a fast infrared radiative transfer model...

  9. Interannual variability of terrestrial evapotranspiration in Northeast Asia

    NASA Astrophysics Data System (ADS)

    Jang, K.; Kang, S.; Hong, S. Y.

    2014-12-01

    Terrestrial evapotranspiration (ET) is a major component for the land surface water cycle and the energy interaction between land surface and atmosphere, and for the improvement of understandings such as the terrestrial water management as well as vegetation growth. Satellite remote sensing provides a promising opportunity to quantify the magnitude and variability of ET at the regional scale. This study investigated the interannual variability of ET in Northeast Asian regions containing Korea Peninsula, China, Mongolia, and Japan. The regional daily ET was estimated using various satellite remote sensing data from 2003 to 2010. Satellite-based daily ET calculations showed generally favorable agreement (RMSE < 1.06 mm day-1) with eight flux tower measurements. Annual ET showed large range in study domain from 466 in 2006 to 498 mm yr-1 in 2008. The mean annual ET for study period was 481.1±224.6 mm yr-1 over the Northeast Asia. ET rates were generally higher at the cropland in China, while it was lower at the grassland in Mongolia. In general, large variability of annual ET was detected in central and northern China and eastern parts of Mongolia and Russia, which are dominated by Grassland, Savanna and Shrubland classifications as well as complex terrain. The range of coefficient of variation (CV) on annual ET was from 15 to 30% at those regions. The spatial pattern of CV was similar to the ratio of ET to TRMM precipitation (ET2PRCP) for the arid and semi-arid regions represented to grassland in this domain. CV on ET was generally high when the ET2PRCP was within the range from 0.7 to 1.5. It indicates that precipitation may affect to variation of annual ET at for the arid and semi-arid regions. The results generated by this study indicated that the satellite remote sensing provides the potentials to estimate and monitor ET at the regional scale, and offers a good chance to improve our knowledge on the land surface water balance.

  10. Two sapogenins from tribulus terrestris

    Microsoft Academic Search

    Yi-Xin Xu; Hai-Sheng Chen; Wen-Yong Liu; Zheng-Bing Gu; Hua-Qing Liang

    1998-01-01

    Studies on the constituents of Tribulus terrestris L. led to the isolation of two new steroidal sapogenins, (5?, 25R)-spirostan-3,6,12-trione and 25R-spirostan-4-ene-3,6,12-trione, together with five known steroidal sapogenins, tigogenin, hecogenin, gitogenin, hecogenone, and 25R-spirostan-4-ene-3,12-dione. The structures of the new sapogenins were established on the basis of chemical and spectroscopic evidence, especially 2D NMR spectroscopic techniques.

  11. Natural organobromine in terrestrial ecosystems

    NASA Astrophysics Data System (ADS)

    Leri, Alessandra C.; Myneni, Satish C. B.

    2012-01-01

    Recent studies have shown that bromine undergoes biogeochemical cycling involving natural formation and degradation of organobromine compounds in marine systems. In the terrestrial environment, where background bromine levels tend to be low, the biogeochemistry of this element remains largely unexamined. We traced the path of bromine through plant growth, senescence, and decay of leaf litter on the forest floor. Using sensitive X-ray spectroscopic techniques, we show that all bromine in humified plant material, organic-rich surface soils, and isolated humic substances is bonded to carbon. Analysis of bromide-enriched plants suggests that bromide absorbed by the growing plants ultimately converts to organobromine when the plant litter decays. Application of isolated chloroperoxidase, a halogenating enzyme, to healthy plant material results in extensive bromination, with organobromine formed preferentially over organochlorine. The relative ease of bromide oxidation appears to promote biogeochemical transformations of Br from inorganic to organic forms, leading to its incorporation into soil organic matter through enzymatic processes related to plant litter decomposition. In combination with low concentration and susceptibility to leaching and plant uptake, natural bromination processes lead to the exhaustion of inorganic bromide in surface soils, making organic matter a reservoir of bromine in the terrestrial environment. This study provides the first detailed look into the terrestrial bromine cycle and lays the foundation for future studies of natural organobromine degradation, which may shed light on the fate of anthropogenic organobromine pollutants in the soil environment.

  12. Arsenic Speciation of Terrestrial Invertebrates

    SciTech Connect

    Moriarty, M.M.; Koch, I.; Gordon, R.A.; Reimer, K.J. ((Simon)); ((Royal))

    2009-07-01

    The distribution and chemical form (speciation) of arsenic in terrestrial food chains determines both the amount of arsenic available to higher organisms, and the toxicity of this metalloid in affected ecosystems. Invertebrates are part of complex terrestrial food webs. This paper provides arsenic concentrations and arsenic speciation profiles for eight orders of terrestrial invertebrates collected at three historical gold mine sites and one background site in Nova Scotia, Canada. Total arsenic concentrations, determined by inductively coupled plasma mass spectrometry (ICP-MS), were dependent upon the classification of invertebrate. Arsenic species were determined by high-performance liquid chromatography (HPLC) ICP-MS and X-ray absorption spectroscopy (XAS). Invertebrates were found by HPLC ICP-MS to contain predominantly arsenite and arsenate in methanol/water extracts, while XAS revealed that most arsenic is bound to sulfur in vivo. Examination of the spatial distribution of arsenic within an ant tissue highlighted the differences between exogenous and endogenous arsenic, as well as the extent to which arsenic is transformed upon ingestion. Similar arsenic speciation patterns for invertebrate groups were observed across sites. Trace amounts of arsenobetaine and arsenocholine were identified in slugs, ants, and spiders.

  13. Time-Bounded Kolmogorov Complexity May Help in Search for Extra Terrestrial Intelligence (SETI)

    Microsoft Academic Search

    M. Schmidt

    1999-01-01

    One of the main strategies in Search for Extra Terrestrial Intelligence (SETI) is trying to overhearcommunications between advanced civilizations. However, there is a (seeming) problem with this approach:advanced civilizations, most probably, save communication expenses by maximally compressingtheir messages, and the notion of a maximally compressed message is naturally formalized as a messagex for which Kolmogorov complexity C(x) is close to

  14. Operating a terrestrial Internet router onboard and alongside a small satellite

    E-print Network

    Wood, Lloyd

    built communication between the satellite and ground station network around a Cisco router and common1 Operating a terrestrial Internet router onboard and alongside a small satellite L. Wood,@ A. da, Richfield, Ohio. * Surrey Satellite Technology Ltd, University of Surrey, Guildford, UK. + DMC International

  15. Personal Communication Systems Using Multiple Hierarchical Cellular Overlays

    Microsoft Academic Search

    Long-rong Hu; Stephen S. Rappaport

    1995-01-01

    A personal communication system with multiple hierarchical cellular overlays is considered. The system can include a terrestrial segment and a space segment. The terrestrial trail segment, consisting of microcells and macrocells, provides high channel capacity by covering service areas with microcells. Overlaying macrocells cover spots that are difficult in radio propagation for microcells and provide overflow groups of channels for

  16. Comparative Climatology of Terrestrial Planets

    NASA Astrophysics Data System (ADS)

    Mackwell, Stephen J.; Simon-Miller, Amy A.; Harder, Jerald W.; Bullock, Mark A.

    Public awareness of climate change on Earth is currently very high, promoting significant interest in atmospheric processes. We are fortunate to live in an era where it is possible to study the climates of many planets, including our own, using spacecraft and groundbased observations as well as advanced computational power that allows detailed modeling. Planetary atmospheric dynamics and structure are all governed by the same basic physics. Thus differences in the input variables (such as composition, internal structure, and solar radiation) among the known planets provide a broad suite of natural laboratory settings for gaining new understanding of these physical processes and their outcomes. Diverse planetary settings provide insightful comparisons to atmospheric processes and feedbacks on Earth, allowing a greater understanding of the driving forces and external influences on our own planetary climate. They also inform us in our search for habitable environments on planets orbiting distant stars, a topic that was a focus of Exoplanets, the preceding book in the University of Arizona Press Space Sciences Series. Quite naturally, and perhaps inevitably, our fascination with climate is largely driven toward investigating the interplay between the early development of life and the presence of a suitable planetary climate. Our understanding of how habitable planets come to be begins with the worlds closest to home. Venus, Earth, and Mars differ only modestly in their mass and distance from the Sun, yet their current climates could scarcely be more divergent. Our purpose for this book is to set forth the foundations for this emerging science and to bring to the forefront our current understanding of atmospheric formation and climate evolution. Although there is significant comparison to be made to atmospheric processes on nonterrestrial planets in our solar system — the gas and ice giants — here we focus on the terrestrial planets, leaving even broader comparisons to a future volume. Our authors have taken on the task to look at climate on the terrestrial planets in the broadest sense possible — by comparing the atmospheric processes at work on the four terrestrial bodies, Earth, Venus, Mars, and Titan (Titan is included because it hosts many of the common processes), and on terrestrial planets around other stars. These processes include the interactions of shortwave and thermal radiation with the atmosphere, condensation and vaporization of volatiles, atmospheric dynamics, chemistry and aerosol formation, and the role of the surface and interior in the long-term evolution of climate. Chapters herein compare the scientific questions, analysis methods, numerical models, and spacecraft remote sensing experiments of Earth and the other terrestrial planets, emphasizing the underlying commonality of physical processes. We look to the future by identifying objectives for ongoing research and new missions. Through these pages we challenge practicing planetary scientists, and most importantly new students of any age, to find pathways and synergies for advancing the field. In Part I, Foundations, we introduce the fundamental physics of climate on terrestrial planets. Starting with the best studied planet by far, Earth, the first chapters discuss what is known and what is not known about the atmospheres and climates of the terrestrial planets of the solar system and beyond. In Part II, Greenhouse Effect and Atmospheric Dynamics, we focus on the processes that govern atmospheric motion and the role that general circulation models play in our current understanding. In Part III, Clouds and Hazes, we provide an in-depth look at the many effects of clouds and aerosols on planetary climate. Although this is a vigorous area of research in the Earth sciences, and very strongly influences climate modeling, the important role that aerosols and clouds play in the climate of all planets is not yet well constrained. This section is intended to stimulate further research on this critical subject. The study of climate involves much more than

  17. Superconductors and cryogenics for future communication systems

    Microsoft Academic Search

    Matthias Klauda; T. Kasser; B. Mayer; C. Neumann; F. Schnell; B. Aminov; A. Baumfalk; H. Chaloupka; S. Kolesov; H. Piel; N. Klein; S. Schornstein; M. Bareiss

    2000-01-01

    In the framework of a German research program on “superconductors and ceramics for future communication technology”, efforts are undertaken to demonstrate the feasibility of cryogenic and high-temperature superconductor technology for applications in communication satellites and base transceiver stations (BTS's) for terrestrial mobile communication. For the receiver front end of C-band satellites, noise reduction filters as well as input-multiplexer channel filters

  18. Combination of satellite based thermal remote sensing and in situ radon measurements and field observations to detect (submarine) groundwater discharge

    NASA Astrophysics Data System (ADS)

    Mallast, U.; Schubert, M.; Schmidt, A.; Knoeller, K.; Stollberg, R.; Siebert, C.; Merz, R.

    2012-12-01

    Submarine groundwater discharge (SGD) is an important factor in the understanding and sustainable management of coastal freshwater aquifers in many highly populated coastal areas worldwide. This is not only due to the fact that SGD represents (i) a significant pathway for transfer of matter between land and sea as it supplies nutrients and trace metals to coastal oceans and (ii) a contamination threat to the near-shore marine environment resulting from land-based activities. It means also that potentially significant freshwater quantities are lost to the sea in e.g. arid areas, where groundwater is the main water resource (IAEA, 2007). The quantitative estimation of SGD is complicated due to its large temporal and spatial variability. Several studies attempted to quantify SGD rates using seepage meters, piezometers or geochemical tracers (Taniguchi et al., 2002). In most of these studies the actual SGD locations were known. In cases of unknown discharge locations airborne- and recently spaceborne-thermal remote sensing were used for detection (Roxburgh, 1985; Wilson and Rocha, 2012). Presented approaches applied only single images that represent only a temporal snapshot and hence possibly a non-representative picture of the discharge behavior (e.g. stormdriven or dry periods). Due to the continuous satellite image recording (Landsat TM/ETM+), numerous images exist that can be exploited against the background of temperature contrasts between discharging groundwater and ocean water. Hence, integrating multiple images recorded at different times does not only account for the intermittent character of groundwater discharge but enables to derive representative SGD information. We will present a satellite-based multi-thermal image method which exploits the fact that continuously discharging groundwater stabilizes the temperature at the discharge location and hence displays small temperature variability. In contrast, ambient unaffected areas clearly follow the seasonal air temperature course resulting in high temperature variability. The temperature variability analysis in combination with a pre-processing step in which images with surface-runoff influence are excluded outlines thermal anomalies that are directly attributable to SGD areas. We applied this method at three different locations along the Dead Sea (Israel/ Palestine), the Black Sea (Romania) and the Mediterranean Sea (France). The sites represent similar hydrogeological conditions (limestone) but different topographical (steep and flat) settings, groundwater temperatures and climatic conditions. We will show that despite these differences, which result in diverse SGD amounts and flux character, the method is capable of indicating areas where continuous SGD occurs over large spatial scales. Based on the thermal indications that were used as a prescreening tool in situ radon measurements and in case of the Dead Sea field observations were pursued to validate the thermal indications. We will show that both results match. Hence we state that our approach represents a promising tool (i) to detect SGD on large spatial scales particularly in areas where a priori no or limited information is available and (ii) to reduce time and financial efforts in pursuing subsequent SGD measurements as the outlined areas can be set as focus areas.

  19. Satellite-based VIS/IR multispectral screening of precipitating clouds: A case study during summer at mid-latitudes

    NASA Astrophysics Data System (ADS)

    Cattani, Elsa; Acquistapace, Claudia; Laviola, Sante; Levizzani, Vincenzo

    2013-04-01

    Precipitation is a fundamental component of the water cycle and essential to the biosphere as a primary source of fresh water. It regulates very diverse phenomena as floods and droughts, soil moisture, ocean salinity and atmospheric circulation associated to the release of latent heat. For these reasons in recent years many studies have focused on the detection of precipitating clouds, in particular by exploiting the VIS/IR spectral channels of the geostationary satellite sensors, in order to provide a characterization of precipitating cloud systems on time scales consistent with their nature and development and oriented to potential operational applications. A precipitating cloud (PC) detection methodology based on Thies et al. (2008) was implemented, by exploiting MSG spectral channels and rain rates from the NIMROD radar network, and its performances were evaluated against NIMROD data and other satellite based PC detection techniques. The methodology is based on a statistical approach. Probability Index (PI) Look Up Tables are calculated as a function of combinations of MSG VIS/NIR/IR channels, selected on the basis of the analysis of coincident MSG and rain radar data, and by taking into account the different illumination conditions (daytime, nighttime, and twilight). The PI represents the probability to detect a pixel covered by a PC. PI threshold values to discriminate between precipitating and non-precipitating clouds are determined using radar data and statistical analysis. A three month dataset from summer 2009 over the NIMROD radar network area (North-West Europe) is employed, composed by spatially and temporally collocated, parallax-corrected MSG data and radar rain rates. The algorithm set up is done for the months of July and August. The algorithm outputs are then compared for the month of June with the Precipitating Clouds PGE04 product from the Satellite Application Facility on Support to Nowcasting and Very Short Range Forecasting and the rainfall intensities from the 183-WSL algorithm (Laviola and Levizzani, 2011) to investigate strengths and limitations of the methodology. Despite of the short time span of the evaluation data set, some preliminary conclusions can be drawn. The daytime version of the algorithm exhibits the best skills in identifying PCs with cold tops, optically thick and associated with moderate-intense rain intensities. In addition, it also shows a certain ability to detect stratiform precipitating water clouds. The algorithm has a tendency to slightly overestimate the rainfall areas, but, on the other hand, the missed events are generally associated with low average rain rates (0.6 - 0.8 mm h-1). Finally, a discontinuity in the PC algorithm performances is noted when switching from twilight to daytime conditions and vice versa due to the different algorithm set up for daytime and twilight. Laviola S., and V. Levizzani, 2011: The 183-WSL fast rain rate retrieval algorithm. Part I: Retrieval design. Atmos. Res., 99, 3-4, 443-461. Thies B., T. Nauss, and J. Bendix, 2008: Discriminating raining from non-raining clouds at mid-latitudes using Meteosat Second Generation daytime data. Atmos. Chem. Phys., 8, 2341-2349.

  20. Downscaling Satellite-based Passive Microwave Observations Using the Principle of Relevant Information and Auxiliary High Resolution Remote Sensing Products

    NASA Astrophysics Data System (ADS)

    Nagarajan, K.; Judge, J.; Principe, J.

    2011-12-01

    Hydrometeorological models simulate the atmospheric and hydrological processes at scales of 1- 10 km that are significantly influenced by the local and regional availability of soil moisture. Microwave observations at frequencies < 10 GHz are highly sensitive to changes in near-surface moisture and have been widely used to retrieve soil moisture information. While satellite-based active microwave observations are available at spatial resolutions of hundreds of meters, with temporal resolutions of several weeks, passive observations are obtained only at tens of kilometers with temporal resolutions of sub daily to 2-3 days. The European Space Agency-Soil Moisture and Ocean Salinity (ESA-SMOS) and the near-future NASA-Soil Moisture Active Passive (SMAP) missions will provide unprecedented passive microwave observations of brightness temperatures (TB) at the L-band frequency of 1.4 GHz. These products will be available at spatial resolutions of about 40-50 km and need to be downscaled to 1 km to merge them with models for data assimilation and to study the effects of land surface heterogeneity such as dynamic vegetation conditions. Very few studies have directly downscaled coarse-resolution TB observations to match model scales. Since downscaling is an ill-posed problem, additional information is required at the fine scales and some studies have leveraged auxiliary high-resolution remote sensing (RS) products in downscaling TB. Most of the above studies involve a) physical models that are computationally intensive when extended to global scales, or b) multi-scale algorithms that impose hierarchical models on TB assuming spatial homogeneity, or c) statistical algorithms that are based on second-order statistics such as variances and correlations. These approaches are therefore sub-optimal when applied to the real data or extended to regional/global scales. Optimal downscaling requires computationally-efficient algorithms that retain information from higher-order moments, especially under heterogeneous land surface conditions. Novel transformation functions leveraging physical relationships and recent advances in signal processing techniques can be used to transform information from high-resolution RS products into TB. In this study, a downscaling methodology was developed using the Principle of Relevant Information (PRI) to downscale observations of TB from 50 km to 200 m using observations of land surface temperature, leaf area index, and land cover at 200 m. The PRI provides a hierarchical decomposition of image data that is optimal in terms of the transfer of information across scales and is therefore a better alternative to methods that use second-order statistics only. Non-parametric probability density functions and Bayes' rule was used to transform information from the RS products into TB. An Observing System Simulation Experiment was developed under heterogeneous and dynamic vegetation conditions to generate synthetic observations at 200m to evaluate the downscaling methodology and the transformation functions.

  1. Information -Communication Communication des entreprises

    E-print Network

    Sart, Remi

    Information - Communication 2 PARCOURS Communication des entreprises Communication et solidarité;2 Information - Communication UFR Langues Appliquées, Commerce et Communication PRÉSENTATION Objectifs La Licence Information et communication est destinée aux étudiants qui souhaitent suivre un parcours

  2. MODIS-Derived Terrestrial Primary Production

    Microsoft Academic Search

    Maosheng Zhao; Steven Running; Faith Ann Heinsch; Ramakrishna Nemani

    \\u000a Temporal and spatial changes in terrestrial biological productivity have a large impact on humankind because terrestrial ecosystems\\u000a not only create environments suitable for human habitation, but also provide materials essential for survival, such as food,\\u000a fiber and fuel. A recent study estimated that consumption of terrestrial net primary production (NPP; a list of all the acronyms\\u000a is available in the

  3. Groundwater and Terrestrial Water Storage

    NASA Technical Reports Server (NTRS)

    Rodell, Matthew; Chambers, Don P.; Famiglietti, James S.

    2014-01-01

    Terrestrial water storage (TWS) comprises groundwater, soil moisture, surface water, snow,and ice. Groundwater typically varies more slowly than the other TWS components because itis not in direct contact with the atmosphere, but often it has a larger range of variability onmultiannual timescales (Rodell and Famiglietti, 2001; Alley et al., 2002). In situ groundwaterdata are only archived and made available by a few countries. However, monthly TWSvariations observed by the Gravity Recovery and Climate Experiment (GRACE; Tapley et al.,2004) satellite mission, which launched in 2002, are a reasonable proxy for unconfinedgroundwater at climatic scales.

  4. Satellite-Based Analysis of Evapotranspiration and Water Balance in the Grassland Ecosystems of Dryland East Asia

    PubMed Central

    Xia, Jiangzhou; Liang, Shunlin; Chen, Jiquan; Yuan, Wenping; Liu, Shuguang; Li, Linghao; Cai, Wenwen; Zhang, Li; Fu, Yang; Zhao, Tianbao; Feng, Jinming; Ma, Zhuguo; Ma, Mingguo; Liu, Shaomin; Zhou, Guangsheng; Asanuma, Jun; Chen, Shiping; Du, Mingyuan; Davaa, Gombo; Kato, Tomomichi; Liu, Qiang; Liu, Suhong; Li, Shenggong; Shao, Changliang; Tang, Yanhong; Zhao, Xiang

    2014-01-01

    The regression tree method is used to upscale evapotranspiration (ET) measurements at eddy-covariance (EC) towers to the grassland ecosystems over the Dryland East Asia (DEA). The regression tree model was driven by satellite and meteorology datasets, and explained 82% and 76% of the variations of ET observations in the calibration and validation datasets, respectively. The annual ET estimates ranged from 222.6 to 269.1 mm yr?1 over the DEA region with an average of 245.8 mm yr?1 from 1982 through 2009. Ecosystem ET showed decreased trends over 61% of the DEA region during this period, especially in most regions of Mongolia and eastern Inner Mongolia due to decreased precipitation. The increased ET occurred primarily in the western and southern DEA region. Over the entire study area, water balance (the difference between precipitation and ecosystem ET) decreased substantially during the summer and growing season. Precipitation reduction was an important cause for the severe water deficits. The drying trend occurring in the grassland ecosystems of the DEA region can exert profound impacts on a variety of terrestrial ecosystem processes and functions. PMID:24845063

  5. Far-IR semiconductor laser for future THz-carrier free-space communications

    E-print Network

    Peale, Robert E.

    prospects for application to secure satellite and short-range terrestrial free-space communications on a THz, satellite communication 1. INTRODUCTION Free space communications using THz carrier frequencies is severely of the Air Force, which partially supports this work (see acknowledgments). Airborne/satellite communications

  6. Study of vulnerability of electronic communication systems to electronic interception, volume 1

    Microsoft Academic Search

    C. W. Sanders; G. F. Sandy; J. F. Sawyer; A. Schneider

    1977-01-01

    The vulnerability of commonly available electronic communications to unauthorized interception was investigated. Common and specialized carrier and privately owned communications systems were studied. Various forms of communication such as analog and digital communications carried by dedicated service and switched service systems were analyzed. The transmission modes considered were terrestrial and satellite microwave systems, mobile radio systems and wire and cable

  7. On the use of satellite-based estimates of rainfall temporal distribution to simulate the potential for malaria transmission in rural Africa

    NASA Astrophysics Data System (ADS)

    Yamana, Teresa K.; Eltahir, Elfatih A. B.

    2011-02-01

    This paper describes the use of satellite-based estimates of rainfall to force the Hydrology, Entomology and Malaria Transmission Simulator (HYDREMATS), a hydrology-based mechanistic model of malaria transmission. We first examined the temporal resolution of rainfall input required by HYDREMATS. Simulations conducted over Banizoumbou village in Niger showed that for reasonably accurate simulation of mosquito populations, the model requires rainfall data with at least 1 h resolution. We then investigated whether HYDREMATS could be effectively forced by satellite-based estimates of rainfall instead of ground-based observations. The Climate Prediction Center morphing technique (CMORPH) precipitation estimates distributed by the National Oceanic and Atmospheric Administration are available at a 30 min temporal resolution and 8 km spatial resolution. We compared mosquito populations simulated by HYDREMATS when the model is forced by adjusted CMORPH estimates and by ground observations. The results demonstrate that adjusted rainfall estimates from satellites can be used with a mechanistic model to accurately simulate the dynamics of mosquito populations.

  8. Tectonic evolution of terrestrial planets

    NASA Technical Reports Server (NTRS)

    Head, J. W.; Solomon, S. C.

    1981-01-01

    The tectonic style of each terrestrial planet, referring to the thickness and division of its lithosphere, can be inferred from surface features and compared to models of planetary thermal history. Factors governing planetary tectonic evolution are planet diameter, chemistry, and external and internal heat sources, all of which determine how a planet generates and rids itself of heat. The earth is distinguished by its distinct, mobile plates, which are recycled into the mantle and show large-scale lateral movements, whereas the moon, Mars, and Mercury are single spherical shells, showing no evidence of destruction and renewal of the lithospheric plates over the latter 80% of their history. Their smaller volume to surface area results in a more rapid cooling, formation, and thickening of the lithosphere. Vertical tectonics, due to lithospheric loading, is controlled by the local thickness and rheology of the lithosphere. Further studies of Venus, which displays both the craterlike surface features of the one-plate planets, and the rifts and plateaus of earth, may indicate which factors are most important in controlling the tectonic evolution of terrestrial planets.

  9. The Laboratory for Terrestrial Physics

    NASA Technical Reports Server (NTRS)

    2003-01-01

    The Laboratory for Terrestrial Physics is dedicated to the advancement of knowledge in Earth and planetary science, by conducting innovative research using space technology. The Laboratory's mission and activities support the work and new initiatives at NASA's Goddard Space Flight Center (GSFC). The Laboratory's success contributes to the Earth Science Directorate as a national resource for studies of Earth from Space. The Laboratory is part of the Earth Science Directorate based at the GSFC in Greenbelt, MD. The Directorate itself is comprised of the Global Change Data Center (GCDC), the Space Data and Computing Division (SDCD), and four science Laboratories, including Laboratory for Terrestrial Physics, Laboratory for Atmospheres, and Laboratory for Hydrospheric Processes all in Greenbelt, MD. The fourth research organization, Goddard Institute for Space Studies (GISS), is in New York, NY. Relevant to NASA's Strategic Plan, the Laboratory ensures that all work undertaken and completed is within the vision of GSFC. The philosophy of the Laboratory is to balance the completion of near term goals, while building on the Laboratory's achievements as a foundation for the scientific challenges in the future.

  10. Cadaver decomposition in terrestrial ecosystems.

    PubMed

    Carter, David O; Yellowlees, David; Tibbett, Mark

    2007-01-01

    A dead mammal (i.e. cadaver) is a high quality resource (narrow carbon:nitrogen ratio, high water content) that releases an intense, localised pulse of carbon and nutrients into the soil upon decomposition. Despite the fact that as much as 5,000 kg of cadaver can be introduced to a square kilometre of terrestrial ecosystem each year, cadaver decomposition remains a neglected microsere. Here we review the processes associated with the introduction of cadaver-derived carbon and nutrients into soil from forensic and ecological settings to show that cadaver decomposition can have a greater, albeit localised, effect on belowground ecology than plant and faecal resources. Cadaveric materials are rapidly introduced to belowground floral and faunal communities, which results in the formation of a highly concentrated island of fertility, or cadaver decomposition island (CDI). CDIs are associated with increased soil microbial biomass, microbial activity (C mineralisation) and nematode abundance. Each CDI is an ephemeral natural disturbance that, in addition to releasing energy and nutrients to the wider ecosystem, acts as a hub by receiving these materials in the form of dead insects, exuvia and puparia, faecal matter (from scavengers, grazers and predators) and feathers (from avian scavengers and predators). As such, CDIs contribute to landscape heterogeneity. Furthermore, CDIs are a specialised habitat for a number of flies, beetles and pioneer vegetation, which enhances biodiversity in terrestrial ecosystems. PMID:17091303

  11. On communications with extra-terrestrial or alien intelligences

    Microsoft Academic Search

    R. P. Haviland

    1975-01-01

    The discussion deals with two questions: assuming a signal has been detected, does the signal contain a message. If so, how can it be deciphered. The concept of the message as a statistical variate is explained. When the suspected sequence of elements is examined for randomness, if any departure from randomness is found, the presence of a message is indicated.

  12. Intraspecific Communication Communication

    E-print Network

    Dever, Jennifer A.

    taxa communicate? 1. Amphibians a) Caecilians b) Salamanders c) Frogs 2. Reptiles a) Turtles b) Crocs c Contact Alarm 1) Visual 2) Chemical 3) Acoustic 4) Tactile #12;2 1. Amphibian communication a. Caecilians

  13. Advanced Stirling conversion systems for terrestrial applications

    Microsoft Academic Search

    Shaltens

    1987-01-01

    Sandia National Laboratories (SNLA) is developing heat engines for terrestrial Solar distributed Heat Receivers. SNLA has identified the Stirling to be one of the most promising candidates for the terrestrial applications. The free-piston Stirling engine (FPSE) has the potential to meet the DOE goals for both performance and cost. Free-piston Stirling activities which are directed toward a dynamic power source

  14. JONATHAN CODDINGTON Estimating terrestrial biodiversity through extrapolation

    E-print Network

    Mathis, Wayne N.

    1994 JONATHAN CODDINGTON Estimating terrestrial biodiversity through extrapolation ROBERT K. The organization of terrestrial biodiversity 102 3. Richness and complementarity 103 (a) Concepts 103 (b global biodiversity require that we make the most of what we know through the use of estimation

  15. Collisional Evolution of Terrestrial Planets

    NASA Astrophysics Data System (ADS)

    Agnor, C. B.; Asphaug, E. I.

    2003-05-01

    The currently accepted model for the formation of terrestrial planets describes their growth as the collisional accumulation of rocky or sometimes molten planetesimals. The characteristics of the planets produced by this process are, to a large degree, determined by their collisional evolution, and their associated differentiation and thermal evolution. Studies of planet formation and planetary collisional evolution have typically been conducted separately. Most works of late-stage planet formation use perfectly inelastic mergers to model collisions (e.g. Agnor, Canup & Levison 1999, Chambers 2001, Levison & Agnor 2003), with certain recognized inadequacies, notably rotationally unstable spin rates acquired as a planet grows. Do planets really accrete in this manner? On the other hand, most of the work studying the collisional evolution of terrestrial planets has focused on determining the efficacy of single impacts to account for particular planetary characteristics and the formation of satellites (e.g. Benz et al. 1988, Canup & Asphaug 2001). It has been recognized for some time (Wetherill 1985) that the final characteristics (e.g. spin state, bulk composition, isotopic age) of an accreting planet are determined not by the last or single largest collision (Agnor, Canup & Levison 1999) but by all of the major collisional encounters in a planet's history. As demonstrated in our impact models, each major impact changes the silicate to metal ratio, the thermal state, and the spin state, and sets the stage for subsequent collisions. We have commenced a detailed study of collision dynamics and outcomes common to the late stage of terrestrial planet accretion. We are modeling collisions using smooth particle hydrodynamics to examine, primarily, the regimes of impact that truly allow for accretion (i.e. mass accumulation instead of mass loss). We are also studying the cumulative affect of giant impacts on major planetary characteristics (such as composition and spin) and the extent to which collisional processes may account for planetary heterogeneity. One initial outcome of this study, to be presented, is whether, and under which circumstances, the use of perfectly inelastic collisions in late stage accretion studies is appropriate.

  16. Collisional Evolution of Terrestrial Planets

    NASA Astrophysics Data System (ADS)

    Agnor, C.; Asphaug, E.

    2004-12-01

    The terrestrial planets are generally thought to have formed via the collisional accumulation of rocky bodies. The characteristics of the planets produced by this process are, to a large degree, determined by their collisional evolution, and their associated differentiation and thermal evolution. Studies of planet formation and planetary collisional evolution have typically been conducted separately. Most works of late-stage planet formation use perfectly inelastic mergers to model collisions (e.g. Agnor, Canup & Levison 1999, Chambers 2001, Levison & Agnor 2003), with certain recognized inadequacies, notably prohibitively large spin angular momentum acquired as a planet grows. To date, studies of the collisional evolution of terrestrial planets has focused on determining the efficacy of single impacts to account for particular planetary characteristics and the formation of satellites (e.g. Benz et al. 1988, Canup & Asphaug 2001, Canup 2004). It has been recognized for some time (Wetherill 1985) that the final characteristics (e.g. spin state, bulk composition, isotopic age) of an accreting planet are determined not by the last or single largest collision but by all of the major collisional encounters in a planet's history (Agnor, Canup & Levison 1999). As demonstrated by our impact models, each major impact changes the silicate to metal ratio, the thermal state, and the spin state, and sets the stage for the subsequent collision. We are studying collisional dynamics and outcomes common to the late stage of terrestrial planet formation. We use smooth particle hydrodynamics model collisions in an effort to identify the range of impact dynamics that allow for accretion (i.e. mass growth instead of mass loss). In our initial study we found that for dynamical environments typical of most late stage accretion models, about half of all collisions between equal mass planetary embryos do not result in accumulation into a larger embryo (Agnor & Asphaug 2004). We will present new results of collisions for a variety of mass ratios and will discuss the cumulative affect of giant impacts and non-accretionary collisions on planetary characteristics (e.g. Mercury's collisional mantle loss and bulk composition, planetary spin states) and the extent to which collisional processes may account for planetary heterogeneity.

  17. NCA-LDAS: An Integrated Terrestrial Water Analysis System for Development, Evaluation, and Dissemination of Climate Indicators

    NASA Astrophysics Data System (ADS)

    Jasinski, M. F.; Arsenault, K. R.; Beaudoing, H. K.; Bolten, J. D.; Borak, J.; Kumar, S.; Peters-Lidard, C. D.; Li, B.; Liu, Y.; Mocko, D. M.; Rodell, M.

    2014-12-01

    An Integrated Terrestrial Water Analysis System, or NCA-LDAS, has been created to enable development, evaluation, and dissemination of terrestrial hydrologic climate indicators focusing on the continental U.S. The purpose is to provide quantifiable indicators of states and estimated trends in our nation's water stores and fluxes over a wide range of scales and locations, to support improved understanding and management of water resources and numerous related sectors such as agriculture and energy. NCA-LDAS relies on improved modeling of terrestrial hydrology through assimilation of satellite imagery, building upon the legacy of the Land Information System modeling framework (Kumar et al, 2006; Peters-Lidard et al, 2007). It currently employs the Noah or Catchment Land Surface Model, run with a number of satellite data assimilation scenarios. The domain for NCA-LDAS is the continental U.S. at 1/8 degree grid for the period 1979 to present. Satellite-based variables that are assimilated are soil moisture and snow water equivalent from principally microwave sensors such as SMMR, SSM/I and AMSR, snow covered area from multispectral sensors such as AVHRR, and MODIS, and terrestrial water storage from GRACE. Once simulated, output are evaluated in comparison to independent datasets using a variety of metrics using the Land Surface Verification Toolkit (LVT). LVT schemes within NCA-LDAS also include routines for computing standard statistics of time series such means, max, and linear trends, at various scales. The dissemination of the NCA-LDAS, including model descriptions, forcings, parameters, daily output, indicator results and LVT tools, have been made available to the public through dissemination on NASA GES-DISC.

  18. Insignificant solar-terrestrial triggering of earthquakes

    USGS Publications Warehouse

    Love, Jeffrey J.; Thomas, Jeremy N.

    2013-01-01

    We examine the claim that solar-terrestrial interaction, as measured by sunspots, solar wind velocity, and geomagnetic activity, might play a role in triggering earthquakes. We count the number of earthquakes having magnitudes that exceed chosen thresholds in calendar years, months, and days, and we order these counts by the corresponding rank of annual, monthly, and daily averages of the solar-terrestrial variables. We measure the statistical significance of the difference between the earthquake-number distributions below and above the median of the solar-terrestrial averages by ?2 and Student's t tests. Across a range of earthquake magnitude thresholds, we find no consistent and statistically significant distributional differences. We also introduce time lags between the solar-terrestrial variables and the number of earthquakes, but again no statistically significant distributional difference is found. We cannot reject the null hypothesis of no solar-terrestrial triggering of earthquakes.

  19. Terrestrial Planet Formation at Home and Abroad

    E-print Network

    Raymond, Sean N; Morbidelli, Alessandro; Morishima, Ryuji; Walsh, Kevin J

    2013-01-01

    We review the state of the field of terrestrial planet formation with the goal of understanding the formation of the inner Solar System and low-mass exoplanets. We review the dynamics and timescales of accretion from planetesimals to planetary embryos and from embryos to terrestrial planets. We discuss radial mixing and water delivery, planetary spins and the importance of parameters regarding the disk and embryo properties. Next, we connect accretion models to exoplanets. We first explain why the observed hot Super Earths probably formed by in situ accretion or inward migration. We show how terrestrial planet formation is altered in systems with gas giants by the mechanisms of giant planet migration and dynamical instabilities. Standard models of terrestrial accretion fail to reproduce the inner Solar System. The "Grand Tack" model solves this problem using ideas first developed to explain the giant exoplanets. Finally, we discuss whether most terrestrial planet systems form in the same way as ours, and high...

  20. Possible climates on terrestrial exoplanets

    E-print Network

    Forget, Francois

    2013-01-01

    What kind of environment may exist on terrestrial planets around other stars? In spite of the lack of direct observations, it may not be premature to speculate on exoplanetary climates, for instance to optimize future telescopic observations, or to assess the probability of habitable worlds. To first order, climate primarily depends on 1) The atmospheric composition and the volatile inventory; 2) The incident stellar flux; 3) The tidal evolution of the planetary spin, which can notably lock a planet with a permanent night side. The atmospheric composition and mass depends on complex processes which are difficult to model: origins of volatile, atmospheric escape, geochemistry, photochemistry. We discuss physical constraints which can help us to speculate on the possible type of atmosphere, depending on the planet size, its final distance for its star and the star type. Assuming that the atmosphere is known, the possible climates can be explored using Global Climate Models analogous to the ones developed to sim...

  1. Steroidal glycosides from Tribulus terrestris

    Microsoft Academic Search

    Gong Wu; Shanhao Jiang; Fuxiang Jiang; Dayuan Zhu; Houming Wu; Shaokai Jiang

    1996-01-01

    In addition to hecogenin 3-O-?-d-glucopyranosyl(1 ? 4)-?-d-galactopyranoside, two new steroidal saponins were isolated from the aerial parts of Tribulus terrestris L. On the basis of chemical and spectroscopic evidence, especially 2D NMR spectroscopic techniques, the structures of the new saponins were established as 26-O-?-d-glucopyranosyl-3-O-[{?-d-xylopyranosyl(1 ? 3)}{?-d-galactopyranosyl(1 ? 2)}-?-d-glucopyranosyl (1 ? 4)-?-d-glucopyranosyl]-5?-furost-20(22)-en-12-one-3?,26-diol and 26-O-?-d-glucopyranosyl-3-O-[rm[{?-d-xylopyranosyl(1 ? 3){?-d-galactopyranosyl(1 ? 2)}-?-d-glucopyranosyl (1 ? 4)-?-d-glucopyranosyl]-5?-furostan-12-one-3?,22,26-triol.

  2. Phytopharmacological overview of Tribulus terrestris.

    PubMed

    Chhatre, Saurabh; Nesari, Tanuja; Somani, Gauresh; Kanchan, Divya; Sathaye, Sadhana

    2014-01-01

    Tribulus terrestris (family Zygophyllaceae), commonly known as Gokshur or Gokharu or puncture vine, has been used for a long time in both the Indian and Chinese systems of medicine for treatment of various kinds of diseases. Its various parts contain a variety of chemical constituents which are medicinally important, such as flavonoids, flavonol glycosides, steroidal saponins, and alkaloids. It has diuretic, aphrodisiac, antiurolithic, immunomodulatory, antidiabetic, absorption enhancing, hypolipidemic, cardiotonic, central nervous system, hepatoprotective, anti-inflammatory, analgesic, antispasmodic, anticancer, antibacterial, anthelmintic, larvicidal, and anticariogenic activities. For the last few decades or so, extensive research work has been done to prove its biological activities and the pharmacology of its extracts. The aim of this review is to create a database for further investigations of the discovered phytochemical and pharmacological properties of this plant to promote research. This will help in confirmation of its traditional use along with its value-added utility, eventually leading to higher revenues from the plant. PMID:24600195

  3. Methane production in terrestrial arthropods.

    PubMed Central

    Hackstein, J H; Stumm, C K

    1994-01-01

    We have screened more than 110 representatives of the different taxa of terrestrial arthropods for methane production in order to obtain additional information about the origins of biogenic methane. Methanogenic bacteria occur in the hindguts of nearly all tropical representatives of millipedes (Diplopoda), cockroaches (Blattaria), termites (Isoptera), and scarab beetles (Scarabaeidae), while such methanogens are absent from 66 other arthropod species investigated. Three types of symbiosis were found: in the first type, the arthropod's hindgut is colonized by free methanogenic bacteria; in the second type, methanogens are closely associated with chitinous structures formed by the host's hindgut; the third type is mediated by intestinal anaerobic protists with intracellular methanogens. Such symbiotic associations are likely to be a characteristic property of the particular taxon. Since these taxa represent many families with thousands of species, the world populations of methane-producing arthropods constitute an enormous biomass. We show that arthropod symbionts can contribute substantially to atmospheric methane. Images PMID:8202505

  4. A Spherical Aerial Terrestrial Robot

    NASA Astrophysics Data System (ADS)

    Dudley, Christopher J.

    This thesis focuses on the design of a novel, ultra-lightweight spherical aerial terrestrial robot (ATR). The ATR has the ability to fly through the air or roll on the ground, for applications that include search and rescue, mapping, surveillance, environmental sensing, and entertainment. The design centers around a micro-quadcopter encased in a lightweight spherical exoskeleton that can rotate about the quadcopter. The spherical exoskeleton offers agile ground locomotion while maintaining characteristics of a basic aerial robot in flying mode. A model of the system dynamics for both modes of locomotion is presented and utilized in simulations to generate potential trajectories for aerial and terrestrial locomotion. Details of the quadcopter and exoskeleton design and fabrication are discussed, including the robot's turning characteristic over ground and the spring-steel exoskeleton with carbon fiber axle. The capabilities of the ATR are experimentally tested and are in good agreement with model-simulated performance. An energy analysis is presented to validate the overall efficiency of the robot in both modes of locomotion. Experimentally-supported estimates show that the ATR can roll along the ground for over 12 minutes and cover the distance of 1.7 km, or it can fly for 4.82 minutes and travel 469 m, on a single 350 mAh battery. Compared to a traditional flying-only robot, the ATR traveling over the same distance in rolling mode is 2.63-times more efficient, and in flying mode the system is only 39 percent less efficient. Experimental results also demonstrate the ATR's transition from rolling to flying mode.

  5. Solar Terrestrial Relations Observatory (STEREO)

    NASA Technical Reports Server (NTRS)

    Davila, Joseph M.; SaintCyr, O. C.

    2003-01-01

    The solar magnetic field is constantly generated beneath the surface of the Sun by the solar dynamo. To balance this flux generation, there is constant dissipation of magnetic flux at and above the solar surface. The largest phenomenon associated with this dissipation is the Coronal Mass Ejection (CME). The Solar and Heliospheric Observatory (SOHO) has provided remarkable views of the corona and CMEs, and served to highlight how these large interplanetary disturbances can have terrestrial consequences. STEREO is the next logical step to study the physics of CME origin, propagation, and terrestrial effects. Two spacecraft with identical instrument complements will be launched on a single launch vehicle in November 2007. One spacecraft will drift ahead and the second behind the Earth at a separation rate of 22 degrees per year. Observation from these two vantage points will for the first time allow the observation of the three-dimensional structure of CMEs and the coronal structures where they originate. Each STEREO spacecraft carries a complement of 10 instruments, which include (for the first time) an extensive set of both remote sensing and in-situ instruments. The remote sensing suite is capable of imaging CMEs from the solar surface out to beyond Earth's orbit (1 AU), and in-situ instruments are able to measure distribution functions for electrons, protons, and ions over a broad energy range, from the normal thermal solar wind plasma to the most energetic solar particles. It is anticipated that these studies will ultimately lead to an increased understanding of the CME process and provide unique observations of the flow of energy from the corona to the near-Earth environment. An international research program, the International Heliophysical Year (IHY) will provide a framework for interpreting STEREO data in the context of global processes in the Sun-Earth system.

  6. Comparing cropland net primary production estimates from inventory, a satellite-based model, and a process-based model in the Midwest of the United States

    SciTech Connect

    Li, Zhengpeng; Liu, Shuguang; Tan, Zhengxi; Bliss, N.; Young, Claudia J.; West, Tristram O.; Ogle, Stephen

    2014-05-06

    Accurately quantifying the spatial and temporal variability of net primary production (NPP) for croplands is essential to understand regional cropland carbon dynamics. We compared three NPP estimates for croplands in the Midwestern United States: inventory-based estimates using crop yield data from the U.S. Department of Agriculture (USDA) National Agricultural Statistics Service (NASS); estimates from the satellite-based Moderate Resolution Imaging Spectroradiometer (MODIS) NPP product; and estimates from the General Ensemble biogeochemical Modeling System (GEMS) process-based model. The three methods estimated mean NPP in the range of 469–687 g C m?2 yr?1 and total NPP in the range of 318–490 Tg C yr?1 for croplands in the Midwest in 2007 and 2008. The NPP estimates from crop yield data and the GEMS model showed the mean NPP for croplands was over 650 g C m?2 yr?1 while the MODIS NPP product estimated the mean NPP was less than 500 g C m?2 yr?1. MODIS NPP also showed very different spatial variability of the cropland NPP from the other two methods. We found these differences were mainly caused by the difference in the land cover data and the crop specific information used in the methods. Our study demonstrated that the detailed mapping of the temporal and spatial change of crop species is critical for estimating the spatial and temporal variability of cropland NPP. We suggest that high resolution land cover data with species–specific crop information should be used in satellite-based and process-based models to improve carbon estimates for croplands.

  7. Use of satellite-based aerosol optical depth and spatial clustering for PM2.5 prediction and concentration trends in the New England region, U.S

    NASA Astrophysics Data System (ADS)

    Lee, H.; Coull, B. A.; Bell, M. L.; Kang, C.; Koutrakis, P.

    2012-12-01

    The efficacy of air pollution emission control policies can be evaluated by investigating the concentration trends of ambient air pollutants. Satellite-based PM2.5 monitoring has the potential to complement the ground monitoring networks, especially for regions with sparsely distributed monitors. In our study, we predicted daily ambient PM2.5 concentrations using Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical depth (AOD) and spatial clustering and subsequently examined the PM2.5 concentration trends in the New England region, U.S. for the period 2000-2008. The daily calibration of MODIS AOD data using ground PM2.5 measurements in the mixed effects model rendered AOD a robust predictor of ground PM2.5 concentrations. Also the spatial clustering made it possible to estimate PM2.5 concentrations when AOD values were not available (i.e., non-retrieval days). Overall, we predicted daily surface PM2.5 concentrations (including both retrieval and non-retrieval days) with reasonably high R2 (0.83) and low percent mean relative error (3.5%). Based on the daily predicted PM2.5 concentrations, we found higher concentration decreases in urban areas than in rural ones and the highest and lowest decreases during the winter and the summer, respectively. These concentration trends provide evidence that primary particle concentrations decreased more relative to secondary particle ones during the study period. This is also supported by ground speciation data which showed stronger downward concentration trend of primary pollutants including black carbon (BC; -4.5% per year) compared to that of secondary ones including sulfate (SO42-, -2.4% per year). The satellite-based approach of examining spatial patterns of concentration trends, in combination with ground PM2.5 speciation data, can be of tremendous regulatory importance.

  8. The initial IERS Terrestrial Reference Frame.

    NASA Astrophysics Data System (ADS)

    Boucher, C.; Altamimi, Z.

    1989-06-01

    The IERS standards has adopted a description of the Convential Terrestrial Reference System (CTRS) to be used for all IERS activities. In order to facilitate the actual implementation of the IERS Terrestrial Reference System (ITRS) by the various analysis centers which participate to IERS, but also by potential users, this study presents several informations which could be useful for these purposes: 1. A critical description of the latest TRF established by BIH, namely BTS 87. 2. A currently improved combination of BTS 87 input data, following strictly the IERS standards, and to be used as Initial IERS Terrestrial Reference Frame (ITRF-0). 3. Some suggestions for implementation of the ITRS.

  9. Bibliography of terrestrial impact structures

    NASA Technical Reports Server (NTRS)

    Grolier, M. J.

    1985-01-01

    This bibliography lists 105 terrestrial impact structures, of which 12 are proven structures, that is, structures associated with meteorites, and 93 are probable. Of the 93 probable structures, 18 are known to contain rocks with meteoritic components or to be enriched in meteoritic signature-elements, both of which enhance their probability of having originated by impact. Many of the structures investigated in the USSR to date are subsurface features that are completely or partly buried by sedimentary rocks. At least 16 buried impact structures have already been identified in North America and Europe. No proven nor probable submarine impact structure rising above the ocean floor is presently known; none has been found in Antarctica or Greenland. An attempt has been made to cite for each impact structure all literature published prior to mid-1983. The structures are presented in alphabetical order by continent, and their geographic distribution is indicated on a sketch map of each continent in which they occur. They are also listed tables in: (1) alphabetical order, (2) order of increasing latitude, (3) order of decreasing diameter, and (4) order of increasing geologic age.

  10. Steroidal saponins from Tribulus terrestris.

    PubMed

    Kang, Li-Ping; Wu, Ke-Lei; Yu, He-Shui; Pang, Xu; Liu, Jie; Han, Li-Feng; Zhang, Jie; Zhao, Yang; Xiong, Cheng-Qi; Song, Xin-Bo; Liu, Chao; Cong, Yu-Wen; Ma, Bai-Ping

    2014-11-01

    Sixteen steroidal saponins, including seven previously unreported compounds, were isolated from Tribulus terrestris. The structures of the saponins were established using 1D and 2D NMR spectroscopy, mass spectrometry, and chemical methods. They were identified as: 26-O-?-d-glucopyranosyl-(25R)-furost-4-en-2?,3?,22?,26-tetrol-12-one (terrestrinin C), 26-O-?-d-glucopyranosyl-(25R)-furost-4-en-22?,26-diol-3,12-dione (terrestrinin D), 26-O-?-d-glucopyranosyl-(25S)-furost-4-en-22?,26-diol-3,6,12-trione (terrestrinin E), 26-O-?-d-glucopyranosyl-(25R)-5?-furostan-3?,22?,26-triol-12-one (terrestrinin F), 26-O-?-d-glucopyranosyl-(25R)-furost-4-en-12?,22?,26-triol-3-one (terrestrinin G), 26-O-?-d-glucopyranosyl-(1?6)-?-d-glucopyranosyl-(25R)-furost-4-en-22?,26-diol-3,12-dione (terrestrinin H), and 24-O-?-d-glucopyranosyl-(25S)-5?-spirostan-3?,24?-diol-12-one-3-O-?-d-glucopyranosyl-(1?4)-?-d-galactopyranoside (terrestrinin I). The isolated compounds were evaluated for their platelet aggregation activities. Three of the known saponins exhibited strong effects on the induction of platelet aggregation. PMID:25172515

  11. EHF space systems: Experimental missions for broadband communications

    Microsoft Academic Search

    Marina Ruggieri; E rnestina Cianca; Tommaso Rossi; Marco Lucente; Cosimo Stallo; Giuseppe Codispoti; Lamberto Zuliani

    2009-01-01

    In the last years scientific community has been witness of the growing interest in global EHF satellite systems for broadband communications; these systems can help national and regional telecommunications service operators to provide broadband communications in areas not adequately served by terrestrial systems. In this paper main EHF satellite missions are presented, outlining challenges and future perspectives.

  12. Grene-Terrestrial Model Intercomparison Project in Arctic (GTMIP)

    NASA Astrophysics Data System (ADS)

    Saito, K.; Miyazaki, S.; Mori, J.; Ise, T.; Yamazaki, T.; Arakida, H.

    2014-12-01

    The GTMIP, a part of the terrestrial branch on Japan-funded Arctic Climate Change Research (GRENE-TEA), aims to 1) enhance communications and understanding of the "mind and hands" between the modeling and field scientists, and 2) assess the uncertainty and variations stemmed from the model implementation/designation, and the variability due to climatic and historical conditions among the Arctic terrestrial regions. The target metrics cover both physics and biogeochemistry such as snow, permafrost, hydrology, and carbon budget. The MIP consists of two stages: one-dimensional, historical GRENE-TEA site evaluations (stage 1) and circumpolar evaluations using projected climate change data from GCM outputs (stage 2). At the current stage 1, forcing and validation data are prepared, taking maximum advantage of the observation data taken at GRENE-TEA sites (e.g., Fairbanks in Alaska, Yakutsk and Tiksi in Russia, and Kevo in Finland), to evaluate the inter-model and inter-site variations. Since the observation data are prone to missing or lack of the consistency, and not ready to drive the numerical model directly, we create continuous forcing data (called version 0) derived from the reanalysis product (i.e. ERA-interim) with monthly bias corrections using the CRU (for temperature) and GPCP (for precipitation) datasets taken from the respectively nearest grid to the GRENE-TEA sites. Then, it is modified to reflect the local characteristics (version 1), and, in addition, replaced with the observed data (version 1 with obs). These data are partly open at Arctic Data Archive System. The project is open to any modelers who are interested, and welcomes participation of wide range of the terrestrial models possibly with different levels of complexity and philosophy.

  13. Data Distribution and Documenting Uncertainty Information for the Earth System Data Record: The Global Terrestrial Water Cycle

    NASA Astrophysics Data System (ADS)

    MacCracken, R. F.; Wood, E. F.; Sheffield, J.; Lettenmaier, D. P.; Houser, P.; Pinker, R. T.; Kummerow, C.; Pan, M.; Gao, H.; Sahoo, A. K.; Bytheway, J. L.

    2012-12-01

    A new balanced global terrestrial water cycle dataset is being created for the NASAs' Making Earth Science Data Records for use in Research Environments (MEaSURE) project. This dataset will be comprised of multiple remotely-sensed datasets and model generated data, and will be merged into a single unified multi-decade, high spatial resolution, climate consistent Earth Science Data Record (ESDR). In addition to the final unified ESDR, the seven remotely-sensed and model generated input datasets will also be available as ESDRs. These input datasets are: (1) VIC model derived water cycle variables, (3 hourly, from 1948 - 2010, on a 0.25 degree grid); (2) Satellite derived precipitation data from two separate sources: (a) GPCC data, (monthly, from 1983 - 1998, on a 0.5 degree grid), and (b) TRMM TMPA data, (3 hourly, from 1998 - 2010, on a 0.25 degree grid); (3) Satellite derived evapotranspiration data, based on the SRB/ISCCP radiation forcings, ( 3 hourly, from 1983 - 2007, on a 0.5 degree spatial resolution; (4) Satellite based soil moisture is derived from multiple satellite sensors, but, primarily the TRMM TMI and AMSR-E, (daily, from 1998 - 2011, on a 0.25 degree grid); (5) Satellite derived water management variables (monthly, from 1992 - 2010, on a variable degree grid); (6) Satellite derived surface radiations, based on ISCCP-DX data, (3 hourly, from 1983 - 2007, on a 0.5 degree grid) (7) Model derived Surface Meteorological Forcing Fields (3 hourly, from 1948 - 2010, on a 0.25 degree grid). Along with these ESDRs, it is also necessary to distribute uncertainty information about the data. Including this information will assist the data users with how much error there is in the estimations in the data, the limitations in the data, as well as knowing how the final merged components of the water balance equation was weighted in order to obtain a balanced equation. This uncertainty information was generated from either the producers of the individual datatsets and/or the water imbalance corrections required to to produce the final unified dataset. Because of the multiple producers of this information, it is necessary to document these sources and methodologies. At the end of the project, these datasets will be available through the NASA Goddard Earth Sciences (GES) Data and Information Services Center (DISC), however, as input datasets become available for input processing, they are placed onto a dedicated project server, at George Mason University, and made available to the public, using such tools as FTP and the GrADS-DODS data server. This server provides the web infrastructure to communicate and distribute the large amount of data and documentations/metadata to the community. Along with these distribution tools, metrics were put in place to track user information, such as origins and number of visits and datasets downloaded. This poster illustrates the methodology used to generate the uncertainty information for a few of the input ESDRs. Because there are multiple methods for calculating this uncertainty, it was necessary to include as much information about how these estimates were obtained, as well as other relevant information within the metadata. To address this issue, standard metadata constructs were used to describe the data, and pass information along to the user.

  14. The Geology of the Terrestrial Planets

    NASA Technical Reports Server (NTRS)

    Carr, M. H. (editor); Saunders, R. S.; Strom, R. G.; Wilhelms, D. E.

    1984-01-01

    The geologic history of the terrestrial planets is outlined in light of recent exploration and the revolution in geologic thinking. Among the topics considered are planet formation; planetary craters, basins, and general surface characteristics; tectonics; planetary atmospheres; and volcanism.

  15. Space Vehicle Terrestrial Environment Design Requirements Guidelines

    NASA Technical Reports Server (NTRS)

    Johnson, Dale L.; Keller, Vernon W.; Vaughan, William W.

    2006-01-01

    The terrestrial environment is an important driver of space vehicle structural, control, and thermal system design. NASA is currently in the process of producing an update to an earlier Terrestrial Environment Guidelines for Aerospace Vehicle Design and Development Handbook. This paper addresses the contents of this updated handbook, with special emphasis on new material being included in the areas of atmospheric thermodynamic models, wind dynamics, atmospheric composition, atmospheric electricity, cloud phenomena, atmospheric extremes, and sea state. In addition, the respective engineering design elements are discussed relative to terrestrial environment inputs that require consideration. Specific lessons learned that have contributed to the advancements made in the application and awareness of terrestrial environment inputs for aerospace engineering applications are presented.

  16. Terrestrial analogs of the Hellespontus dunes, Mars

    NASA Technical Reports Server (NTRS)

    Breed, C. S.

    1977-01-01

    Geomorphic features in the Hellespontus region, Mars, were compared with dunes of the crescentic ridge type in numerous terrestrial sand seas quantitatively by dimensional analysis of dune lengths, widths, and wavelengths. Mean values for the Hellespontus dunes are close to mean values derived from measurements of all sampled terrestrial sand seas. Terrestrial analogs of form and areal distribution of the Hellespontus dunes are shown by comparison of scale ratios derived from the measurements. Dunes of similar form occur in South West Africa, in Pakistan, in the southeastern Arabian peninsula, in the Sahara, in eastern USSR and northern China, and in western North America. Terrestrial analogs closest to form and areal distribution of the Hellespontus dunes are in the Kara Kum Desert, Turkmen SSR, and in the Ala Shan (Gobi) Desert, China.

  17. Terrestrial Planet Atmospheres. The Moon's Sodium Atmosphere

    E-print Network

    Walter, Frederick M.

    ? ­ Smaller planet mass? ­ Lightweight gases? #12;Venus and the Runaway GreenhouseTerrestrial Planet Atmospheres. II. #12;The Moon's Sodium Atmosphere #12;Mercury for a Planet · Equator heated more than poles · Hadley cell transport heat poleward

  18. Inter-mountain laser communication tests

    NASA Astrophysics Data System (ADS)

    Ruiz, D.; Czichy, R.; Bara, J.; Comeron, A.; Belmonte, A.

    1990-07-01

    Results are presented on laser-diode (LD) based intermountain tests carried out as a support activity to ESA's Free-space Optical Communications program to evaluate the Canary Islands (Spain) as an optical communicaton test range. The model predictions of low atmospheric attentuation and turbulence-induced effects were confirmed by a simple link test between observatories, showing that the Canary Islands are a proper site for performing terrestrial experiments of free-space optical communication systems.

  19. Thin film solar cells for terrestrial applications

    Microsoft Academic Search

    F. A. Shirland; W. J. Biter; E. W. Greeneich; T. P. Brody

    1975-01-01

    The goals of the project are to develop a terrestrial version of the CdS thin film solar cell that is demonstrably amenable to low cost mass production, and to establish data on the lifetime of such cells under the expected conditions of terrestrial use. There were six major tasks for the first year's work. These were: Re-establish the state-of-the-art of

  20. Frequency-hop transmission for satellite packet switching and terrestrial packet radio networks

    Microsoft Academic Search

    Michael B. Pursley

    1986-01-01

    The performance frequency-hop transmission in a packet communication network is analyzed. Satellite multiple-access broadcast channels for packet switching and terrestrial packet radio networks are the primary examples of the type of network considered. An analysis of the effects of multiple-access interference in frequency-hop radio networks is presented. New measures of 'local' performance are defined and evaluated for networks of this

  1. Communication section Communication section

    E-print Network

    Richner, Heinz

    Rectorate Communication section Communication section Hochschulstrasse 4 CH-3012 Bern Tel. +41 031 project «CHEOPS» (CHaracterizing ExOPlanet Satellite) for Switzerland, which was given the definitive «go projects are closely linked to one another. «CHEOPS» and «PLATO» are satellite missions and deliver data

  2. Propagation prediction models for wireless communication systems

    Microsoft Academic Search

    Magdy F. Iskander; Zhengqing Yun

    2002-01-01

    A comprehensive review of the propagation prediction models for terrestrial wireless communication systems is presented in this paper. The classic empirical models are briefly described and the focus is placed on the application of ray-tracing techniques to the development of deterministic propagation models. Schemes to increase the computational efficiency and accuracy are discussed. Traditional statistical models are also briefly reviewed

  3. Manual of satellite communications

    NASA Astrophysics Data System (ADS)

    Fthenakis, E.

    The design and operation of satellite communications systems (SCSs) are examined in an introductory text for graduate engineering students. The history of SCSs during the period 1962-1982 is traced with an emphasis on US commercial ventures, and the overall function and economics of SCSs is reviewed. Individual chapters are devoted to orbits, launch sequences, and on-station positioning; spacecraft systems; communications payloads; earth stations and terrestrial links; uplinks and downlinks; linear systems and signals; random processes and noise; analog modulation; digital communicatins; coding and forward error detection; transmission impairments; and networks and systems (multiplexing, FDMA, TDMA, CDMA, and variable-access demand asignment. Graphs showing the apparent motion of the sun with respect to an earth satellite; summaries of Fourier analysis, Hilbert transforms, vector and matrix representations; and a table listing the characteristics of major SCSs are included in appendices.

  4. Possible climates on terrestrial exoplanets.

    PubMed

    Forget, F; Leconte, J

    2014-04-28

    What kind of environment may exist on terrestrial planets around other stars? In spite of the lack of direct observations, it may not be premature to speculate on exoplanetary climates, for instance, to optimize future telescopic observations or to assess the probability of habitable worlds. To begin with, climate primarily depends on (i) the atmospheric composition and the volatile inventory; (ii) the incident stellar flux; and (iii) the tidal evolution of the planetary spin, which can notably lock a planet with a permanent night side. The atmospheric composition and mass depends on complex processes, which are difficult to model: origins of volatiles, atmospheric escape, geochemistry, photochemistry, etc. We discuss physical constraints, which can help us to speculate on the possible type of atmosphere, depending on the planet size, its final distance for its star and the star type. Assuming that the atmosphere is known, the possible climates can be explored using global climate models analogous to the ones developed to simulate the Earth as well as the other telluric atmospheres in the solar system. Our experience with Mars, Titan and Venus suggests that realistic climate simulators can be developed by combining components, such as a 'dynamical core', a radiative transfer solver, a parametrization of subgrid-scale turbulence and convection, a thermal ground model and a volatile phase change code. On this basis, we can aspire to build reliable climate predictors for exoplanets. However, whatever the accuracy of the models, predicting the actual climate regime on a specific planet will remain challenging because climate systems are affected by strong positive feedbacks. They can drive planets with very similar forcing and volatile inventory to completely different states. For instance, the coupling among temperature, volatile phase changes and radiative properties results in instabilities, such as runaway glaciations and runaway greenhouse effect. PMID:24664919

  5. Frequency allocation problem in a SDMA satellite communication system Laurent Houssin12

    E-print Network

    Paris-Sud XI, Université de

    Frequency allocation problem in a SDMA satellite communication system Laurent Houssin12 , Christian to a clever algorithm in charge of resource allocation. As satellite communication systems move towards) in a satellite communication system involving a gateway connected to a terrestrial network and some user

  6. Proof of concept effort for demonstrating an all-digital satellite communications earth terminal

    Microsoft Academic Search

    H. Beljour; R. Hoffmann; G. Michael; W. Schoonveld; J. Shields; I. Sumit; C. Swenson; A. Willson; T. Curtis; V. Weerackody

    2010-01-01

    The Space and Terrestrial Communications Directorate of the U.S. Army's Communications- Electronics Research, Development and Engineering Center is executing a proof of concept program to develop and demonstrate an All-Digital Satellite Communications Earth Terminal. The Future Advanced Satellite Terminal (FAST) program initially focuses on the satellite terminal's receive component of the satellite link. The two main efforts under FAST are

  7. MODIS-Derived Terrestrial Primary Production

    NASA Astrophysics Data System (ADS)

    Zhao, Maosheng; Running, Steven; Heinsch, Faith Ann; Nemani, Ramakrishna

    Temporal and spatial changes in terrestrial biological productivity have a large impact on humankind because terrestrial ecosystems not only create environments suitable for human habitation, but also provide materials essential for survival, such as food, fiber and fuel. A recent study estimated that consumption of terrestrial net primary production (NPP; a list of all the acronyms is available in the appendix at the end of the chapter) by the human population accounts for about 14-26% of global NPP (Imhoff et al. 2004). Rapid global climate change is induced by increased atmospheric greenhouse gas concentration, especially CO2, which results from human activities such as fossil fuel combustion and deforestation. This directly impacts terrestrial NPP, which continues to change in both space and time (Melillo et al. 1993; Prentice et al. 2001; Nemani et al. 2003), and ultimately impacts the well-being of human society (Milesi et al. 2005). Additionally, substantial evidence show that the oceans and the biosphere, especially terrestrial ecosystems, currently play a major role in reducing the rate of the atmospheric CO2 increase (Prentice et al. 2001; Schimel et al. 2001). NPP is the first step needed to quantify the amount of atmospheric carbon fixed by plants and accumulated as biomass. Continuous and accurate measurements of terrestrial NPP at the global scale are possible using satellite data. Since early 2000, for the first time, the MODIS sensors onboard the Terra and Aqua satellites, have operationally provided scientists with near real-time global terrestrial gross primary production (GPP) and net photosynthesis (PsnNet) data. These data are provided at 1 km spatial resolution and an 8-day interval, and annual NPP covers 109,782,756 km2 of vegetated land. These GPP, PsnNet and NPP products are collectively known as MOD17 and are part of a larger suite of MODIS land products (Justice et al. 2002), one of the core Earth System or Climate Data Records (ESDR or CDR).

  8. Pemberton et al: ALIEN TERRESTRIAL ORCHID, EULOPHIA GRAMINEA, INVADES MIAMI ALIEN TERRESTRIAL ORCHID, EULOPHIA GRAMINEA,

    E-print Network

    Koptur, Suzanne

    Pemberton et al: ALIEN TERRESTRIAL ORCHID, EULOPHIA GRAMINEA, INVADES MIAMI 183 ALIEN TERRESTRIAL ORCHID, EULOPHIA GRAMINEA, INVADES MIAMI Bob Pemberton, PhD, Suzanne Koptur, PhD & Timothy Collins, PhD We first encountered an Asian orchid, Eulophia graminea, in South Miami during the autumn of 2007

  9. Early Formation of Terrestrial Crust

    NASA Astrophysics Data System (ADS)

    Harrison, T. M.; Schmitt, A. K.; McCulloch, M. T.; Lovera, O. M.

    2007-12-01

    Early (?4.5 Ga) Formation of Terrestrial Crust T.M. Harrison1, A.K. Schmitt1, M.T. McCulloch2, and O.M. Lovera1 1Department of Earth and Space Sciences and IGPP, UCLA, Los Angeles, CA 90095, USA; 2Research School of Earth Sciences, Australian National University, Canberra, A.C.T. 2601 AUSTRALIA Large deviations in ?repsilonHf(T) from bulk silicate Earth seen in >4 Ga detrital zircons from Jack Hills, Western Australia, have been interpreted as reflecting a major differentiation of the silicate Earth at ca. 4.4 to 4.5 Ga. We have expanded the characterization of 176Hf/177Hf (Hf) in Hadean zircons by acquiring a further 116 laser ablation Lu-Hf measurements on 87 grains with ion microprobe 207Pb/206Pb ages up to 4.36 Ga. Most measurements employed concurrent Lu-Hf and 207Pb/206Pb analyses, permitting assessment of the use of ion microprobe data to characterize the age of the volumetrically larger domain sampled by laser drilling. Our new results confirm and extend the earlier observation of significant negative deviations in ?repsilonHf(T) throughout the Hadean, although no positive ?repsilonHf(T) values were documented in this study. These data yields an essentially uniform spectrum of single-stage model ages between 4.54 and 4.20 Ga for extraction of the zircons' protoliths from a chondritic reservoir. We derived the full error propagation expression for a parameter, ?repsilono, which measures the difference of a sample from solar system initial (Hf) (Hfo), and from this conclude that data plotting close to (Hfo), are statistically meaningful and consistent with silicate differentiation at 4.540±0.006 Ga. ?18O and Ti thermometry for these Hadean zircons show little obvious correlation with initial (Hf), consistent with their derivation through fusion of a broad suite of crustal rock types under near water-saturated conditions. Together with the inclusion assemblage and other isotopic and trace element data obtained from these ancient zircons, our results indicate essentially continuous derivation of crust from the mantle from 4.5 to 4.2 Ga, concurrent with recycling into the mantle and internal crustal re-working. These results represent further evidence that by 4.35 Ga, portions of the crust had taken on continental characteristics.

  10. Satellite Communication.

    ERIC Educational Resources Information Center

    Technology Teacher, 1985

    1985-01-01

    Presents a discussion of communication satellites: explains the principles of satellite communication, describes examples of how governments and industries are currently applying communication satellites, analyzes issues confronting satellite communication, links mathematics and science to the study of satellite communication, and applies…

  11. Satellite-aided land mobile communications system implementation considerations

    NASA Technical Reports Server (NTRS)

    Leroy, B. E.

    1982-01-01

    It was proposed that a satellite-based land mobile radio system could effectively extend the terrestrial cellular mobile system into rural and remote areas. The market, technical and economic feasibility for such a system is studied. Some of the aspects of implementing an operational mobile-satellite system are discussed. In particular, two key factors in implementation are examined: (1) bandwidth requirements; and (2) frequency sharing. Bandwidth requirements are derived based on the satellite antenna requirements, modulation characteristics and numbers of subscribers. Design trade-offs for the satellite system and potential implementation scenarios are identified. Frequency sharing is examined from a power flux density and modulation viewpoint. Previously announced in STAR as N82-25290

  12. Convergence of Mobile Communications and Broadcasting: A long term perspective

    Microsoft Academic Search

    Friedrich K. Jondral; Dennis Burgkhardt; Jens Elsner; Arnold Picot; Nico Grove

    Terrestrial unidirectional broadcasting is currently being substituted by wired bidirectional IP-based services. In practical day-to-day use, user mobility for the 'last mile' is supported by wireless local area networks with massively growing data rates. Terrestrial bidirectional mobile communications, on the other hand, is currently moving into its fourth technological generation. With the new UMTS Long Term Evolution (LTE) standards, data

  13. What is the Safest Way to Cross the Valley of Death: Wisdom gained from Making a Satellite based Flood Forecasting System Operational and Owned by Stakeholders

    NASA Astrophysics Data System (ADS)

    Hossain, F.

    2013-12-01

    More than a decade ago, the National Research Council report popularized the term 'Valley of Death' to describe the region where research on Weather Satellites had struggled to survive before reaching maturity for societal applications. For example, the space vantage of earth observing satellites can solve some of the world's otherwise fundamentally intractable operational problems on water resources. However, recent experiences show that many of the potential beneficiaries, who are not as familiar with water cycle remote sensing missions or anthropogenic climate studies, referred here as the ';non-traditional consumers,' may have a more skeptical view based on their current practices. This talk will focus on one such non-traditional consumer group: the water resources managers/staff in developing nations of South Asia. Using real-world examples on applications and hands-on-training to make a satellite based flood forecasting system operational, the talk will dissect the view that is shared by many water managers of Bangladesh on satellite remote sensing for day to day decision making. The talk will share the experience and wisdom generated in the successful capacity building of emerging satellite technology for water management. It will end with an overview of initiatives for more effective promotion of the value of planned water cycle satellite missions for water resources management community in the developing world.

  14. Comparative planetology: Significance for terrestrial geology

    NASA Technical Reports Server (NTRS)

    Frey, H. V.; Lowman, P. D., R.

    1978-01-01

    The crustal evolution of the terrestrial planets increase in complexity and duration with increasing size and mass of the planet. The lunar and mercurian surfaces are largely the result of intense, post-differentiation impact bombardment and subsequent volcanic filling of major impact basins. Mars, being larger, has evolved further: crustal uplifts, rifting, and shield volcanoes have begun to modify its largely Moon-like surface. The Earth is the large end-number of this sequence, where modern plate tectonic processes have erased the earlier lunar and martian type of surfaces. Fundamental problems of the origin of terrestrial continents, ocean basins, and plate tectonics are now addressed within the context of the evolutionary pattern of the terrestrial planets.

  15. Responses of terrestrial aridity to global warming

    NASA Astrophysics Data System (ADS)

    Fu, Qiang; Feng, Song

    2014-07-01

    The dryness of terrestrial climate can be measured by the ratio of annual precipitation (P) to potential evapotranspiration (PET), where the latter represents the evaporative demand of the atmosphere, which depends on the surface air temperature, relative humidity, wind speed, and available energy. This study examines how the terrestrial mean aridity responds to global warming in terms of P/PET using the Coupled Model Intercomparison Project phase 5 transient CO2 increase to 2 × CO2 simulations. We show that the (percentage) increase (rate) in P averaged over land is ~1.7%/°C ocean mean surface air temperature increase, while the increase in PET is 5.3%/°C, leading to a decrease in P/PET (i.e., a drier terrestrial climate) by ~3.4%/°C. Noting a similar rate of percentage increase in P over land to that in evaporation (E) over ocean, we propose a framework for examining the change in P/PET, in which we compare the change in PET over land and E over ocean, both expressed using the Penman-Monteith formula. We show that a drier terrestrial climate is caused by (i) enhanced land warming relative to the ocean, (ii) a decrease in relative humidity over land but an increase over ocean, (iii) part of increase in net downward surface radiation going into the deep ocean, and (iv) different responses of PET over land and E over ocean for given changes in atmospheric conditions (largely associated with changes in temperatures). The relative contributions to the change in terrestrial mean aridity from these four factors are about 35%, 35%, 15%, and 15%, respectively. The slight slowdown of the surface wind over both land and ocean has little impact on the terrestrial mean aridity.

  16. Magnetic reconnection in the terrestrial magnetosphere

    SciTech Connect

    Feldman, W.C.

    1984-01-01

    An overview is given of quantitative comparisons between measured phenomena in the terrestrial magnetosphere thought to be associated with magnetic reconnection, and related theoretical predictions based on Petschek's simple model. Although such a comparison cannot be comprehensive because of the extended nature of the process and the relatively few in situ multipoint measurements made to date, the agreement is impressive where comparisons have been possible. This result leaves little doubt that magnetic reconnection does indeed occur in the terrestrial magnetosphere. The maximum reconnection rate, expressed in terms of the inflow Mach number, M/sub A/, is measured to be M/sub A/ = 0.2 +- 0.1.

  17. Terrestrial Planet Finder Coronagraph Observatory summary

    NASA Technical Reports Server (NTRS)

    Ford, Virginia; Levine-Westa, Marie; Kissila, Andy; Kwacka, Eug; Hoa, Tim; Dumonta, Phil; Lismana, Doug; Fehera, Peter; Cafferty, Terry

    2005-01-01

    Creating an optical space telescope observatory capable of detecting and characterizing light from extra-solar terrestrial planets poses technical challenges related to extreme wavefront stability. The Terrestrial Planet Finder Coronagraph design team has been developing an observatory based on trade studies, modeling and analysis that has guided us towards design choices to enable this challenging mission. This paper will describe the current flight baseline design of the observatory and the trade studies that have been performed. The modeling and analysis of this design will be described including predicted performance and the tasks yet to be done.

  18. Were early pterosaurs inept terrestrial locomotors?

    PubMed Central

    2015-01-01

    Pterodactyloid pterosaurs are widely interpreted as terrestrially competent, erect-limbed quadrupeds, but the terrestrial capabilities of non-pterodactyloids are largely thought to have been poor. This is commonly justified by the absence of a non-pterodactyloid footprint record, suggestions that the expansive uropatagia common to early pterosaurs would restrict hindlimb motion in walking or running, and the presence of sprawling forelimbs in some species. Here, these arguments are re-visited and mostly found problematic. Restriction of limb mobility is not a problem faced by extant animals with extensive fight membranes, including species which routinely utilise terrestrial locomotion. The absence of non-pterodactyloid footprints is not necessarily tied to functional or biomechanical constraints. As with other fully terrestrial clades with poor ichnological records, biases in behaviour, preservation, sampling and interpretation likely contribute to the deficit of early pterosaur ichnites. Suggestions that non-pterodactyloids have slender, mechanically weak limbs are demonstrably countered by the proportionally long and robust limbs of many Triassic and Jurassic species. Novel assessments of pterosaur forelimb anatomies conflict with notions that all non-pterodactyloids were obligated to sprawling forelimb postures. Sprawling forelimbs seem appropriate for species with ventrally-restricted glenoid articulations (seemingly occurring in rhamphorhynchines and campylognathoidids). However, some early pterosaurs, such as Dimorphodon macronyx and wukongopterids, have glenoid arthrologies which are not ventrally restricted, and their distal humeri resemble those of pterodactyloids. It seems fully erect forelimb stances were possible in these pterosaurs, and may be probable given proposed correlation between pterodactyloid-like distal humeral morphology and forces incurred through erect forelimb postures. Further indications of terrestrial habits include antungual sesamoids, which occur in the manus and pes anatomy of many early pterosaur species, and only occur elsewhere in terrestrial reptiles, possibly developing through frequent interactions of large claws with firm substrates. It is argued that characteristics possibly associated with terrestriality are deeply nested within Pterosauria and not restricted to Pterodactyloidea as previously thought, and that pterodactyloid-like levels of terrestrial competency may have been possible in at least some early pterosaurs. PMID:26157605

  19. Tectonic Evolution of the Terrestrial Planets

    NASA Technical Reports Server (NTRS)

    Solomon, Sean C.; Senski, David G. (Technical Monitor)

    2002-01-01

    The NASA Planetary Geology and Geophysics Program supported a wide range of work on the geophysical evolution of the terrestrial planets during the period 1 April 1997 - 30 September 2001. We here provide highlights of the research carried out under this grant over the final year of the award, and we include a full listing of publications and scientific meeting presentations supported by this project. Throughout the grant period, our group consisted of the Principal Investigator and several Postdoctoral Associates, all at the Department of Terrestrial Magnetism (DTM) of the Carnegie Institution of Washington.

  20. Phenological Patterns of Terrestrial Plants Beverly Rathcke; Elizabeth P. Lacey

    E-print Network

    Lacey, Elizabeth P.

    Phenological Patterns of Terrestrial Plants Beverly Rathcke; Elizabeth P. Lacey Annual Review PHENOLOGICAL PATTERNS OF TERRESTRIAL PLANTS Beverly Rathcke Divisionof Biological Sciences. Hence, phenology is defined as the study of the seasonal timing of life cycle events. Forplants

  1. Center for Research on Enhancing Carbon Sequestration in Terrestrial Ecosystems

    E-print Network

    #12;Center for Research on Enhancing Carbon Sequestration in Terrestrial Ecosystems Personnel. Blaine Metting #12;vii Abstract The Center for Research on Enhancing Carbon Sequestration in Terrestrial needed to evaluate the feasibility of environmentally sound strategies for enhancing carbon sequestration

  2. Leaf element concentrations of terrestrial plants across China are

    E-print Network

    Slik, Ferry

    extracted from publications. The links between envi- ronmental variables, taxonomy and leaf elements wereRESEARCH PAPER Leaf element concentrations of terrestrial plants across China are influenced cycles of terrestrial eco- systems are strongly affected by leaf element concentrations. Understanding

  3. 77 FR 18271 - Terrestrial Environmental Studies for Nuclear Power Stations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-27

    ...Terrestrial Environmental Studies for Nuclear Power Stations AGENCY: Nuclear Regulatory...Terrestrial Environmental Studies for Nuclear Power Stations.'' This guide provides...supporting licensing decisions for nuclear power reactors. ADDRESSES:...

  4. 76 FR 50274 - Terrestrial Environmental Studies for Nuclear Power Stations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-08-12

    ...Terrestrial Environmental Studies for Nuclear Power Stations AGENCY: Nuclear Regulatory...Terrestrial Environmental Studies for Nuclear Power Stations.'' This guide provides...supporting licensing decisions for nuclear power reactors. DATES: Submit...

  5. ESTUARINE WETLANDS (CHAPTER: TERRESTRIAL VEGETATION OF CALIFORNIA)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This chapter on estuarine wetlands is a peer-reviewed contribution to the 3rd edition of Terrestrial Vegetation of California (editors: M.G. Barbour, T. Keeler-Wolf, and A. Schoenherr, University of California Press). The objective of the chapter is to describe the distribution, floristic compositi...

  6. Using observational data to evaluate global terrestrial

    E-print Network

    Atmosphere Coupled Land Models Coupled carbon-climate models disagree on the continued strength of the net to model land-atmosphere carbon exchange #12;Terrestrial Biospheric Models Well-informed Carbon cycle effective carbon management strategies Model evaluation and assessment North American Carbon Program Interim

  7. Fluid Dynamics of a Terrestrial Magma Ocean

    Microsoft Academic Search

    V. S. Solomatov

    2000-01-01

    The scenario of crystallization of a terrestrial magma ocean that seems to be consistent with both fluid dynamical and geochemical constraints is as follows. Even the largest impact is unlikely to melt the Earth completely. After the isostatic adjustment the temperatures at the bottom of the mantle were probably near or somewhat above the solidus. In less than a thousand

  8. Space and Terrestrial Photovoltaics: Synergy and Diversity

    Microsoft Academic Search

    Sheila G. Bailey; Ryne Raffaelle; Keith Emery

    2002-01-01

    A historical view of the research and development in photovoltaics from the perspective of both the terrestrial and the space communities is presented from the early days through the '70s and '80s and the '90s and beyond. The synergy of both communities in the beginning and once again in the present and hopefully future are highlighted, with examples of the

  9. CHANGE DETECTION VIA TERRESTRIAL LASER SCANNING

    Microsoft Academic Search

    Reem Zeibak; Sagi Filin

    2007-01-01

    We present in this paper an algorithm for the detection of changes based on terrestrial laser scanning data. Detection of changes has been a subject for research for many years, seeing applications such as motion tracking, inventory-like comparison and deformation analysis as only a few examples. One of the more difficult tasks in the detection of changes is performing informed

  10. Spiral arms, comets and terrestrial catastrophism

    Microsoft Academic Search

    S. V. M. Clube; W. M. Napier

    1981-01-01

    A hypothesis of terrestrial catastrophism in which comets grow in molecular clouds and are captured by the Sun as it passes through the spiral arms of the galaxy is reviewed. Assuming that comets are a major supplier of the Earth crossing (Apollo) asteroid population, the latter fluctuates correspondingly and leads to episodes of magnetic field reversal and tectonic activity, while

  11. SETI [Search for ExtraTerrestrial Intelligence

    Microsoft Academic Search

    B. M. Oliver

    1994-01-01

    Some critics of the Search for Extra-Terrestrial Intelligence (SETI) like to bolster their arguments with what they call the Fermi Paradox. Legend has it that one day at Los Alamos, shortly after the Alamogordo test (when the first atomic bomb was exploded in the desert about 50 miles northwest of this town on July 16, 1945), Enrico Fermi abruptly broke

  12. Terrestrial ecosystem processes of Victoria Land, Antarctica

    Microsoft Academic Search

    J. E. Barrett; R. A. Virginia; D. W. Hopkins; J. Aislabie; R. Bargagli; J. G. Bockheim; I. B. Campbell; W. B. Lyons; D. L. Moorhead; J. N. Nkem; R. S. Sletten; H. Steltzer; D. H. Wall; M. D. Wallenstein

    2006-01-01

    Terrestrial environments of Victoria Land, Antarctica are ideal systems to test hypotheses about the sensitivity of ecosystem processes to climate variability, and the relationships between soil biodiversity and ecosystem functioning because of their high sensitivity to climate change and their limited diversity. This region is also considered among the most pristine of ecosystems, and therefore may serve as an indicator

  13. Extraterrestrial resources: Implications from terrestrial experience

    Microsoft Academic Search

    David L. Kuck; Stephen L. Gillett

    1991-01-01

    Terrestrial mining experience indicates that the overwhelming criterion of a potentially economic deposit is its recoverable concentration of the desired mineral or element. Recovery can be based on contrast in physical and\\/or chemical properties, but processes based on physical properties are typically less expensive. As several processes generally are used in sequence, they have a profound effect on extraction costs.

  14. Rotation and internal dynamics of terrestrial planets

    Microsoft Academic Search

    V. Dehant

    2009-01-01

    In the last decades, several missions and observations have brought new insight on the inner structure of the terrestrial planets. This information is a big challenge for the planet interior models; these data are also our best chance to improve our knowledge of the interior. Data obtained through new space missions are the basis of the future progress in this

  15. Electromagnetic neutrinos in terrestrial experiments and astrophysics

    E-print Network

    Carlo Giunti; Konstantin A. Kouzakov; Yu-Feng Li; Alexey V. Lokhov; Alexander I. Studenikin; Shun Zhou

    2015-06-17

    An overview of neutrino electromagnetic properties, which open a door to the new physics beyond the Standard Model, is given. The effects of neutrino electromagnetic interactions both in terrestrial experiments and in astrophysical environments are discussed. The experimental bounds on neutrino electromagnetic characteristics are summarized. Future astrophysical probes of electromagnetic neutrinos are outlined.

  16. UV-B EFFECTS ON TERRESTRIAL ECOSYSTEMS

    EPA Science Inventory

    Dpeletion of stratospheric O3 layer should result in enhanced levels of ultraviolet-B (UV-B) radiation at the earth's surface compared to present, with potentially damaging effects on biological systems. his paper briefly summarizes some key findings for UV-B effects on terrestri...

  17. Subsolidus convective cooling histories of terrestrial planets

    Microsoft Academic Search

    G. Schubert; P. Cassen; R. E. Young

    1979-01-01

    The subsolidus convective cooling histories of terrestrial planets evolving from hot initial states are investigated quantitatively. A simple analytic model simulating average heat flux from a vigorously convecting mantle and incorporating a mantle viscosity proportional to mantle temperature and a lithosphere which thickens as the planet cools is employed. Heat flux from the convecting mantle is calculated on the basis

  18. Arbuscular mycorrhizae and terrestrial ecosystem processes

    Microsoft Academic Search

    Matthias C. Rillig

    2004-01-01

    Arbuscular mycorrhizal fungi (AMF; phylum Glomeromycota) are ubiquitous in terrestrial ecosystems. Despite their acknowledged importance in ecology, most research on AMF has focused on effects on individual plant hosts, with more recent efforts aimed at the level of the plant community. Research at the ecosystem level is less prominent, but potentially very promising. Numerous human-induced disturbances (including global change and

  19. Introduction The development of terrestrial reproductive modes

    E-print Network

    Hödl, Walter

    of egg clutches or their exposure to terrestrial predators (MCDIARMID 1978). This in turn creates se- lective pressure for the development of parental care, which WELLS (1981) defined as non-gametic parental clutches 24 hours a day. In order to collect data on the reproduc- tive behaviour of this little

  20. Dinosaurs and the Cretaceous Terrestrial Revolution

    Microsoft Academic Search

    Graeme T. Lloyd; Katie E. Davis; Davide Pisani; James E. Tarver; Marcello Ruta; Manabu Sakamoto; David W. E. Hone; Rachel Jennings; Michael J. Benton

    2008-01-01

    The observed diversity of dinosaurs reached its highest peak during the mid- and Late Cretaceous, the 50 Myr that preceded their extinction, and yet this explosion of dinosaur diversity may be explained largely by sampling bias. It has long been debated whether dinosaurs were part of the Cretaceous Terrestrial Revolution (KTR), from 125-80 Myr ago, when flowering plants, herbivorous and

  1. Terrestrial Photogrammetry of Active Lava Flows

    Microsoft Academic Search

    M. James; S. Robson

    2006-01-01

    In order to improve our understanding of how lavas flow, cool and stop, accurate and frequent DEMs and associated temperature measurements of active flows are required. We describe the use of terrestrial photogrammetric techniques which allow detailed measurements to be carried out rapidly, frequently and over relevant spatial scales. Furthermore, the equipment required is sufficiently small and light to be

  2. Dinosaurs and the Cretaceous Terrestrial Revolution

    E-print Network

    Benton, Michael

    Dinosaurs and the Cretaceous Terrestrial Revolution Graeme T. Lloyd1,*, Katie E. Davis2 , Davide of dinosaurs reached its highest peak during the mid- and Late Cretaceous, the 50 Myr that preceded their extinction, and yet this explosion of dinosaur diversity may be explained largely by sampling bias. It has

  3. Designing avionics for terrestrial neutron environments

    Microsoft Academic Search

    Peter G. Coakley; Dennis Breuner; Randall Milanowski; Marion A. Rose; Amy L. Magnus

    2004-01-01

    This paper presents issues related to effects generated in avionic electronics by terrestrial neutron environments and methods for mitigating the effects through part selection, circuit design and system architecture design. The paper includes an explanation of the System Hardening Upset Recovery (SHUR) technology macro cell library and demonstrates how the available functions can be applied to implement robust system operation

  4. Two new terrestrial Enchytraeus species (Oligochaeta, Annelida)

    Microsoft Academic Search

    W. Westheide; U. Graefe

    1992-01-01

    Enchytraeus crypticus n.sp. and Enchytraeus doerjesi n.sp. were discovered in laboratory cultures of terrestrial enchytraeids in the course of a project evaluating various non-light-microscopical techniques for their taxonomic utility. Ultrastructural and molecular features of the two species are published elsewhere; the present paper describes their conventional morphological characters and their life cycle data under laboratory conditions.

  5. Spaceprobe images and the Terrestrial Planets Section

    Microsoft Academic Search

    G. J. Day

    1981-01-01

    With the formation of a new grouping within the Association - the Terrestrial Planets Section - there is scope for a fresh approach to BAA studies of Mercury, Venus and Mars, incorporating both Earth-based and spacecraft-derived information. Printing Options Send high resolution image to Level 2 Postscript Printer Send low resolution image to Level 2 Postscript Printer Send low resolution

  6. Steroid saponins II. Glycosides of Tribulus terrestris

    Microsoft Academic Search

    P. K. Kintya; É. D. Perepelitsa; V. Ya. Chirva; L. G. Kretsu

    1972-01-01

    Summary  1. It has been established that the epigeal part ofTribulus terrestris L. contains five steroid saponins. Diosgenin was identified as the aglycone of all these compounds.\\u000a \\u000a 2. The carbohydrate compositions of the saponins have been determined.

  7. Alkaloids and other constituents from Tribulus terrestris

    Microsoft Academic Search

    Tian-Shung Wu; Li-Shian Shi; Shang-Chu Kuo

    1999-01-01

    Three new compounds, terrestribisamide, 25R-spirost-4-en-3,12-dione and tribulusterine, together with 10 known compounds, N-p-coumaroyltyramine, terrestriamide, hecogenin, aurantiamide acetate, xanthosine, fatty acid ester, ferulic acid, vanillin, p-hydroxybenzoic acid and ?-sitosterol, were isolated and characterized from dried fruits of Tribulus terrestris. Structures of these compounds were determined by spectral analysis.

  8. Saponins in Tribulus terrestris – Chemistry and Bioactivity

    Microsoft Academic Search

    I. Kostova; D. Dinchev

    2005-01-01

    Tribulus terrestris is a valuable herb known for its application in the folk medicine in many parts of the world. Furostanol and spirostanol saponins of tigogenin, neotigogenin, gitogenin, neogitogenin, hecogenin, neohecogenin, diosgenin, chlorogenin, ruscogenin and sarsasapogenin type are frequently found in this plant. Four sulphated saponins of tigogenin and diosgenin type are also isolated. Extracts and steroidal saponins have been

  9. Neutron production in terrestrial gamma ray flashes

    Microsoft Academic Search

    B. E. Carlson; N. G. Lehtinen

    2010-01-01

    Terrestrial gamma ray flashes (TGFs) are brief bursts of photons with energies up to 20 MeV typically observed in association with lightning. Such energetic photons may undergo photonuclear reactions with nontrivial cross section in the vicinity of the giant dipole resonance. Pulses of neutrons have been observed experimentally in coincidence with lightning, suggesting such reactions are observable. We present simulations

  10. Validation of a terrestrial food chain model

    Microsoft Academic Search

    C. C. Travis; B. P. Blaylock

    1992-01-01

    An increasingly important topic in risk assessment is the estimation of human exposure to environmental pollutants through pathways other than inhalation. The Environmental Protection Agency (EPA) has recently developed a computerized methodology (EPA, 1990) to estimate indirect exposure to toxic pollutants from Municipal Waste Combuster emissions. This methodology estimates health risks from exposure to toxic pollutants from the terrestrial food

  11. Accretion of the terrestrial planets. II

    Microsoft Academic Search

    S. J. Weidenschilling

    1976-01-01

    The theory of gravitational accretion of the terrestrial planets is examined. The concept of a 'closed feeding zone' is somewhat unrealistic, but provides a lower bound on the accretion time. A velocity relation for planetesimals which includes an initial velocity component is suggested. The orbital parameters of the planetesimals and the dimensions of the feeding zone are related to their

  12. High resolution long range terrestrial imaging

    Microsoft Academic Search

    Dan Slater

    2005-01-01

    Achieving high resolution imagery of distant terrestrial objects from ground based sensors presents a unique technical challenge. The entire optical path is fully immersed in a dense and turbulent atmosphere, resulting in a significant loss of scene contrast and resolution. Although there are strong similarities to the problems of high resolution astronomical and space object imaging, there are also some

  13. CONSIDERATIONS FOR PLANNING TERRESTRIAL FIELD STUDIES

    EPA Science Inventory

    In planning a terrestrial field study each component of the study should be considered in the context of all other components. here are close connections between the statement of the research question, the study design, the execution of the study and the final conclusions. hese c...

  14. Trophic polymorphism in a terrestrial salamander

    Microsoft Academic Search

    John C. Maerz; Erin M. Myers

    2006-01-01

    Question: Does habitat heterogeneity promote trophic polymorphism in a terrestrial salamander? Hypothesis: Eastern red-backed salamanders (Plethodon cinereus) in upland and lowland habitats differ morphologically because their prey's size differs between those habitats. Field site: Five mature hardwood forests in central New York and northern Pennsylvania, USA, with known differences in diet between upland and lowland habitats. Methods: We collected animals

  15. 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)

    Mecikalski, John; Smith, Tracy; Weygandt, Stephen

    2014-05-01

    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.

  16. On the ability of RegCM4 to simulate surface solar radiation patterns over Europe: An assessment using satellite-based observations

    NASA Astrophysics Data System (ADS)

    Alexandri, Georgia; Georgoulias, Aristeidis K.; Zanis, Prodromos; Tsikerdekis, Athanasios; Katragkou, Eleni; Kourtidis, Konstantinos; Meleti, Charikleia

    2015-04-01

    We assess here the ability of RegCM4 to simulate the surface solar radiation (SSR) patterns over the European domain. For the needs of this work, a decadal (1999-2009) simulation was implemented at a horizontal resolution of 50km using the first year as a spin-up. The model is driven by emissions from CMIP5 while ERA-interim data were used as lateral boundary conditions. The RegCM4 SSR fields were validated against satellite-based SSR observations from Meteosat First Generation (MFG) and Meteosat Second Generation (MSG) sensors (CM SAF SIS product). The RegCM4 simulations slightly overestimate SSR compared to CM SAF over Europe with the bias being +1.54% in case of MFG (2000-2005) and +3.34% in case of MSG (2006-2009). SSR from RegCM4 is much closer to SSR from CM SAF over land (bias of -1.59% for MFG and +0.66% for MSG) than over ocean (bias of +7.20% for MFG and 8.07% for MSG). In order to understand the reasons of this bias, we proceeded to a detailed assessment of various parameters that define the SSR levels (cloud fractional cover - CFC, cloud optical thickness - COT, cloud droplet effective radius - Re, aerosol optical thickness - AOD, asymmetry factor - ASY, single scattering albedo - SSA, water vapor - WV and surface albedo - ALB). We validated the simulated CFC, COT and Re from RegCM4 against satellite-based observations from MSG and we found that RegCM4 significantly underestimates CFC and Re, and overestimates COT over Europe. The aerosol-related parameters from RegCM4 were compared with values from the aerosol climatology taken into account within CM SAF SSR estimates. AOD is significantly underestimated in our simulations which leads to a positive SSR bias. The RegCM4 WV and ALB were compared with WV values from ERA-interim and ALB climatological observations from CERES which are also taken into account within CM SAF SSR estimates. Finally, with the use of a radiative transfer model (SBDART) we manage to quantify the relative contribution of each of the above mentioned parameters to the total bias appearing between RegCM4 and CM SAF SSR. The research leading to these results has received funding from the European Social Fund (ESF) and national resources under the operational programme Education and Lifelong Learning (EdLL) within the framework of the Action "Supporting Postdoctoral Researchers" (QUADIEEMS project), from EPAN II and PEP under the national action "Bilateral, multilateral and regional R&T cooperations" (AEROVIS Sino-Greek project) and from the European Research Council under the European Union's Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement no. 226144 (C8 project).

  17. Communicating About Communicable Disease

    NSDL National Science Digital Library

    IBM& #39; s Teachers Try Science program

    2011-11-23

    In this "tried and true" investigation, students use a commercially available product (Glo-germ) and a blacklight to demonstrate how germs are spread. Glitter can be substituted. Students then write a public service announcement, including statistics, about the preventing the spread of a communicable disease.

  18. Distributed Assimilation of Satellite-based Snow Extent for Improving Simulated Streamflow in Mountainous, Dense Forests: An Example Over the DMIP2 Western Basins

    NASA Technical Reports Server (NTRS)

    Yatheendradas, Soni; Peters-Lidard, Christa D.; Koren, Victor; Cosgrove, Brian A.; DeGoncalves, Luis G. D.; Smith, Michael; Geiger, James; Cui, Zhengtao; Borak, Jordan; Kumar, Sujay V.; Riggs, George; Mizukami, Naoki

    2012-01-01

    Snow cover area affects snowmelt, soil moisture, evapotranspiration, and ultimately streamflow. For the Distributed Model Intercomparison Project - Phase 2 Western basins, we assimilate satellite-based fractional snow cover area (fSCA) from the Moderate Resolution Imaging Spectroradiometer, or MODIS, into the National Weather Service (NWS) SNOW-17 model. This model is coupled with the NWS Sacramento Heat Transfer (SAC-HT) model inside the National Aeronautics and Space Administration's (NASA) Land Information System. SNOW-17 computes fSCA from snow water equivalent (SWE) values using an areal depletion curve. Using a direct insertion, we assimilate fSCAs in two fully distributed ways: 1) we update the curve by attempting SWE preservation, and 2) we reconstruct SWEs using the curve. The preceding are refinements of an existing simple, conceptually-guided NWS algorithm. Satellite fSCA over dense forests inadequately accounts for below-canopy snow, degrading simulated streamflow upon assimilation during snowmelt. Accordingly, we implement a below-canopy allowance during assimilation. This simplistic allowance and direct insertion are found to be inadequate for improving calibrated results, still degrading them as mentioned above. However, for streamflow volume for the uncalibrated runs, we obtain: (1) substantial to major improvements (64-81 %) as a percentage of the control run residuals (or distance from observations), and (2) minor improvements (16-22 %) as a percentage of observed values. We highlight the need for detailed representations of canopy-snow optical radiative transfer processes in mountainous, dense forest regions if assimilation-based improvements are to be seen in calibrated runs over these areas.

  19. Real-time forecasting at weekly timescales of the SST and SLA of the Ligurian Sea with a satellite-based ocean forecasting (SOFT) system

    NASA Astrophysics Data System (ADS)

    ÁLvarez, A.; Orfila, A.; Tintoré, J.

    2004-03-01

    Satellites are the only systems able to provide continuous information on the spatiotemporal variability of vast areas of the ocean. Relatively long-term time series of satellite data are nowadays available. These spatiotemporal time series of satellite observations can be employed to build empirical models, called satellite-based ocean forecasting (SOFT) systems, to forecast certain aspects of future ocean states. SOFT systems can predict satellite-observed fields at different timescales. The forecast skill of SOFT systems forecasting the sea surface temperature (SST) at monthly timescales has been extensively explored in previous works. In this work we study the performance of two SOFT systems forecasting, respectively, the SST and sea level anomaly (SLA) at weekly timescales, that is, providing forecasts of the weekly averaged SST and SLA fields with 1 week in advance. The SOFT systems were implemented in the Ligurian Sea (Western Mediterranean Sea). Predictions from the SOFT systems are compared with observations and with the predictions obtained from persistence models. Results indicate that the SOFT system forecasting the SST field is always superior in terms of predictability to persistence. Minimum prediction errors in the SST are obtained during winter and spring seasons. On the other hand, the biggest differences between the performance of SOFT and persistence models are found during summer and autumn. These changes in the predictability are explained on the basis of the particular variability of the SST field in the Ligurian Sea. Concerning the SLA field, no improvements with respect to persistence have been found for the SOFT system forecasting the SLA field.

  20. Appendix 57 Predicted Distributions of Terrestrial Vertebrates Species

    E-print Network

    Appendix 57 Predicted Distributions of Terrestrial Vertebrates Species In Idaho and Montana #12;PREDICTED DISTRIBUTIONS OF TERRESTRIAL VERTEBRATE SPECIES IN IDAHO AND MONTANA Acres and Percent native terrestrial vertebrates that breed in Montana and Idaho, with emphasis placed on National Forest

  1. A combined terrestrial reference frame based on space geodesy.

    NASA Astrophysics Data System (ADS)

    Boucher, C.; Altamimi, Z.; Feissel, M.

    1989-06-01

    A terrestrial reference frame of 64 sites has been compiled on the basis of several space geodesy analyses, leading to the last realisation of the Terrestrial System of the BIH, BTS 1987. This realisation provides the initial definition of the IERS Terrestrial System.

  2. The Behaviour ofIodine in the Terrestrial Environment.

    E-print Network

    The Behaviour ofIodine in the Terrestrial Environment. An Investigation of the Possible Roskilde, Denmark Febtuary 1990 #12;1 Risø-M-2851 THE BEHAVIOUR OF IODINE IN THE TERRESTRIAL ENVIRONMENT influence the migration behaviour of iodine in the terrestrial environment. It is stated that the organic

  3. Initiative to quantify terrestrial carbon sources and sinks

    Microsoft Academic Search

    Josef Cihlar; Scott Denning; Frank Ahem; Olivier Arino; Alan Belward; Francis Bretherton; Wolfgang Cramer; Gerard Dedieu; Christopher Field; Roger Francey; Rene Gommes; James Gosz; Kathy Hibbard; Tamotsu Igarashi; Pavel Kabat; Dick Olson; Stephen Plummer; Ichtiaque Rasool; Michael Raupach; Robert Scholes; John Townshend; Riccardo Valentini; Diane Wickland

    2002-01-01

    Questions related to the distribution and spatio-temporal dynamics of the terrestrial carbon fluxes are at the core of current scientific and policy debates. In recent years, the primary concern has been the increasing CO2 content in the atmosphere, its effect on climate, and the associated role of terrestrial ecosystems in mitigating the increase and impact of climate change. However, terrestrial

  4. A new model for rain scatter interference for coordination between Earth stations and terrestrial stations

    NASA Astrophysics Data System (ADS)

    Gibbins, Chris J.

    2005-08-01

    Scattering from rain is known to be a source of possible interference between communications systems sharing the same frequency bands. A new model has been developed for estimating the transmission loss due to bistatic rain scatter between an Earth station and a terrestrial station. This model has particular application in the process of coordination of Earth stations with terrestrial stations operating in the same frequency bands, whereby detailed interference studies are carried out only for stations within an area beyond which harmful interference may be considered negligible. The new model includes the Earth station elevation angle as an input parameter, together with the most recent information on rainfall rates and surface water vapor densities included in the recommendations of the International Telecommunications Union (ITU), and is more flexible yet neutral in its overall impact when applied to the process of coordination as defined in Appendix 7 of the ITU Radio Regulations.

  5. Ecological Biogeography of the Terrestrial Nematodes of Victoria Land, Antarctica 29 Ecological Biogeography of theTerrestrial

    E-print Network

    Wall, Diana

    Ecological Biogeography of the Terrestrial Nematodes of Victoria Land, Antarctica 29 Ecological Biogeography of theTerrestrial Nematodes ofVictoria Land,Antarctica Byron J. Adams1 , Diana H. Wall2 , Ross A of the Terrestrial Nematodes of Victoria Land, Antarctica. ZooKeys 419: 29­71. doi: 10.3897/zookeys.419.7180 Abstract

  6. Space and Terrestrial Photovoltaics: Synergy and Diversity

    NASA Technical Reports Server (NTRS)

    Bailey, Sheila; Raffaelle, Ryne; Emery, Keith

    2002-01-01

    A historical view of the research and development in photovoltaics from the perspective of both the terrestrial and the space communities is presented from the early days through the '70s and '80s and the '90s and beyond. The synergy of both communities in the beginning and once again in the present and hopefully future are highlighted, with examples of the important features in each program. The space community which was impressed by the light-weight and reliability of photovoltaics drove much of the early development. Even up to today, nearly every satellites and other scientific space probe that has been launched has included some solar power. However, since the cost of these power systems were only a small fraction of the satellite and launch cost, the use of much of this technology for the terrestrial marketplace was not feasible. It was clear that the focus of the terrestrial community would be best served by reducing costs. This would include addressing a variety of manufacturing issues and raising the rate of production. Success in these programs and a resulting globalization of effort resulted in major strides in the reduction of PV module costs and increased production. Although, the space community derived benefit from some of these advancements, its focus was on pushing the envelope with regard to cell efficiency. The gap between theoretical efficiencies and experimental efficiencies for silicon, gallium arsenide and indium phosphide became almost non-existent. Recent work by both communities have focused on the development thin film cells of amorphous silicon, CuInSe2 and CdTe. These cells hold the promise of lower costs for the terrestrial community as well as possible flexible substrates, better radiation resistance, and higher specific power for the space community. It is predicted that future trends in both communities will be directed toward advances through the application of nanotechnology. A picture is emerging in which the space and terrestrial solar cell communities shall once again share many common goals and, in fact, companies may manufacture both space and terrestrial solar cells in III-V materials and thin film materials. Basic photovoltaics research including these current trends in nanotechnology provides a valuable service for both worlds in that fundamental understanding of cell processes is still vitally important, particularly with new materials or new cell structures. It is entirely possible that one day we might have one solar array design that will meet the criteria for success in both space and on the Earth or perhaps the Moon or Mars.

  7. The Role of Remote Sensing in Modeling Landscape Change and Its Associated Carbon Cycle Impacts Across Terrestrial Arctic Ecosystems

    NASA Astrophysics Data System (ADS)

    Hayes, D. J.; Goswami, S.; Jones, B. M.; Grosse, G.; Balser, A.; Wullschleger, S. D.

    2014-12-01

    Terrestrial ecosystems across the circumpolar Arctic region are undergoing unprecedented changes in structure and function as a result of rapid climate warming. Such changes have substantially altered energy, water and biogeochemical cycling in these regions, which has important global-scale consequences for climate and society. Recognizing the vulnerability of these ecosystems to change, scientists and decision-makers have identified a critical need for research that employs existing and new remote sensing technologies and methodologies to observe, monitor and understand changes in Arctic ecosystems. The unique capabilities provided by remote sensing imagery and data products have allowed us novel views of ecosystems and their dynamics over multiple scales in time and space across all regions of the globe. Here we offer a synthetic discussion of the recent and emerging science focused on understanding the dynamic landscape processes in Arctic terrestrial ecosystems using a variety of remotely-sensed information collected from passive and active sensors on ground-, aircraft- and satellite- based platforms. To consider the evolution of these technologies, methods and applications over recent decades, we look at key examples from the scientific literature that range from the use of radar sensors for local-scale characterization of active layer dynamics to the circumpolar-scale assessment of changes in vegetation productivity using long-term records of optical satellite imagery. This discussion has a particular focus on the use of remotely sensed data and products to parameterize, drive, evaluate and benchmark the modeling of Arctic ecosystem processes. We use these examples to demonstrate the opportunities for model-data integration, as well as to highlight the challenges of remote sensing studies in northern high latitude regions.

  8. Thermal evolutions of the terrestrial planets

    NASA Technical Reports Server (NTRS)

    Toksoz, M. N.; Hsui, A. T.; Johnston, D. H.

    1978-01-01

    Theoretical models are formulated for the thermal evolution of the moon, Mercury, Mars, Venus, and hypothetical minor planets, with consideration of conduction, solid-state convection, and differentiation. A variety of geological, geochemical and geophysical data is used to constrain both the present-day temperatures and the thermal histories of the planetary interiors. The data imply that the planets were heated during or shortly after formation and that all the terrestrial planets started differentiating early in their history. The size of the planet is the primary factor in determining its present-day thermal state. A planetary body with radius less than 1000 km is unlikely to reach melting, given heat source concentrations similar to terrestrial values and in the absence of intensive early heating.

  9. Evolution of Herbivory in Terrestrial Vertebrates

    NASA Astrophysics Data System (ADS)

    Sues, Hans-Dieter

    2000-08-01

    Although herbivory probably first appeared over 300 million years ago, it only became established as a common feeding strategy during Late Permian times. Subsequently, herbivory evolved in numerous lineages of terrestrial vertebrates, and the acquisition of this mode of feeding was frequently associated with considerable evolutionary diversification in those lineages. This book represents a comprehensive overview of the evolution of herbivory in land-dwelling amniote tetrapods in recent years. In Evolution of Herbivory in Terrestrial Vertebrates, leading experts review the evolutionary history and structural adaptations required for feeding on plants in the major groups of land-dwelling vertebrates, especially dinosaurs and ungulate mammals. As such, this volume will be the definitive reference source on this topic for evolutionary biologists and vertebrate paleontologists.

  10. Application of Terrestrial Environments in Orion Assessments

    NASA Technical Reports Server (NTRS)

    Barbre, Robert E., Jr.

    2015-01-01

    This presentation summarizes the Marshall Space Flight Center Natural Environments Terrestrial and Planetary Environments (TPE) Team support to the NASA Orion space vehicle. The TPE utilizes meteorological data to assess the sensitivities of the vehicle due to the terrestrial environment. The Orion vehicle, part of the Multi-Purpose Crew Vehicle Program, is designed to carry astronauts beyond low-earth orbit and is currently undergoing a series of tests including Exploration Test Flight (EFT) - 1. The presentation describes examples of TPE support for vehicle design and several tests, as well as support for EFT-1 and planning for upcoming Exploration Missions while emphasizing the importance of accounting for the natural environment's impact to the vehicle early in the vehicle's program.

  11. Assessing the impact of end-member selection on the accuracy of satellite-based spatial variability models for actual evapotranspiration estimation

    NASA Astrophysics Data System (ADS)

    Long, Di; Singh, Vijay P.

    2013-05-01

    This study examines the impact of end-member (i.e., hot and cold extremes) selection on the performance and mechanisms of error propagation in satellite-based spatial variability models for estimating actual evapotranspiration, using the triangle, surface energy balance algorithm for land (SEBAL), and mapping evapotranspiration with high resolution and internalized calibration (METRIC) models. These models were applied to the soil moisture-atmosphere coupling experiment site in central Iowa on two Landsat Thematic Mapper/Enhanced Thematic Mapper Plus acquisition dates in 2002. Evaporative fraction (EF, defined as the ratio of latent heat flux to availability energy) estimates from the three models at field and watershed scales were examined using varying end-members. Results show that the end-members fundamentally determine the magnitudes of EF retrievals at both field and watershed scales. The hot and cold extremes exercise a similar impact on the discrepancy between the EF estimates and the ground-based measurements, i.e., given a hot (cold) extreme, the EF estimates tend to increase with increasing temperature of cold (hot) extreme, and decrease with decreasing temperature of cold (hot) extreme. The coefficient of determination between the EF estimates and the ground-based measurements depends principally on the capability of remotely sensed surface temperature (Ts) to capture EF (i.e., depending on the correlation between Ts and EF measurements), being slightly influenced by the end-members. Varying the end-members does not substantially affect the standard deviation and skewness of the EF frequency distributions from the same model at the watershed scale. However, different models generate markedly different EF frequency distributions due to differing model physics, especially the limiting edges of EF defined in the remotely sensed vegetation fraction (fc) and Ts space. In general, the end-members cannot be properly determined because (1) they do not necessarily exist within a scene, varying with the spatial extent, resolution, and quality of satellite images being used and/or (2) different operators can select different end-members. Furthermore, the limiting edge of EF = 0 in the fc-Ts space varies with the model, with SEBAL-type models having inherently an increasing curvilinear limiting edge of EF = 0 with fc. The spatial variability models therefore require careful calibration in order to deduce reasonable EF-limiting edges and then confine the magnitudes of EF estimates.

  12. SPARTAN: a global network to evaluate and enhance satellite-based estimates of ground-level particulate matter for global health applications

    NASA Astrophysics Data System (ADS)

    Snider, G.; Weagle, C. L.; Martin, R. V.; van Donkelaar, A.; Conrad, K.; Cunningham, D.; Gordon, C.; Zwicker, M.; Akoshile, C.; Artaxo, P.; Anh, N. X.; Brook, J.; Dong, J.; Garland, R. M.; Greenwald, R.; Griffith, D.; He, K.; Holben, B. N.; Kahn, R.; Koren, I.; Lagrosas, N.; Lestari, P.; Ma, Z.; Vanderlei Martins, J.; Quel, E. J.; Rudich, Y.; Salam, A.; Tripathi, S. N.; Yu, C.; Zhang, Q.; Zhang, Y.; Brauer, M.; Cohen, A.; Gibson, M. D.; Liu, Y.

    2014-07-01

    Ground-based observations have insufficient spatial coverage to assess long-term human exposure to fine particulate matter (PM2.5) at the global scale. Satellite remote sensing offers a promising approach to provide information on both short- and long-term exposure to PM2.5 at local-to-global scales, but there are limitations and outstanding questions about the accuracy and precision with which ground-level aerosol mass concentrations can be inferred from satellite remote sensing alone. A key source of uncertainty is the global distribution of the relationship between annual average PM2.5 and discontinuous satellite observations of columnar aerosol optical depth (AOD). We have initiated a global network of ground-level monitoring stations designed to evaluate and enhance satellite remote sensing estimates for application in health effects research and risk assessment. This Surface PARTiculate mAtter Network (SPARTAN) includes a global federation of ground-level monitors of hourly PM2.5 situated primarily in highly populated regions and collocated with existing ground-based sun photometers that measure AOD. The instruments, a three-wavelength nephelometer and impaction filter sampler for both PM2.5 and PM10, are highly autonomous. Hourly PM2.5 concentrations are inferred from the combination of weighed filters and nephelometer data. Data from existing networks were used to develop and evaluate network sampling characteristics. SPARTAN filters are analyzed for mass, black carbon, water-soluble ions, and metals. These measurements provide, in a variety of global regions, the key data required to evaluate and enhance satellite-based PM2.5 estimates used for assessing the health effects of aerosols. Mean PM2.5 concentrations across sites vary by an order of magnitude. Initial measurements indicate that the AOD column to PM2.5 ratio is driven temporally primarily by the vertical profile of aerosol scattering; and spatially by a~ more complex interaction of the aerosol scattering vertical profile and by the mass scattering efficiency.

  13. Messaging to Extra-Terrestrial Intelligence

    E-print Network

    Zaitsev, A

    2006-01-01

    Throughout the entire history of terrestrial civilization, only four projects involving transmitting of interstellar radio messages (IRMs) have yet been fully developed and realized. Nevertheless, we should understand a simple thing -- if all civilizations in the Universe are only recipients, and not message-sending civilizations, than no SETI searches make any sense. We present the theory and methodology of composing and transmitting of future IRMs.

  14. Messaging to Extra-Terrestrial Intelligence

    E-print Network

    Alexander Zaitsev

    2006-10-05

    Throughout the entire history of terrestrial civilization, only four projects involving transmitting of interstellar radio messages (IRMs) have yet been fully developed and realized. Nevertheless, we should understand a simple thing -- if all civilizations in the Universe are only recipients, and not message-sending civilizations, than no SETI searches make any sense. We present the theory and methodology of composing and transmitting of future IRMs.

  15. Observed beaming of terrestrial myriametric radiation

    NASA Technical Reports Server (NTRS)

    Jones, Dyfrig; Calvert, W.; Gurnett, D. A.; Huff, R. L.

    1987-01-01

    Observations by the Dynamics Explorer 1 satellite are discussed which validate the theory that terrestrial myriametric radiation (TMR) is produced by the linear conversion of electrostatic upper hybrid waves to electromagnetic radiation via a radio window. A remote sensing technique based on the theory is used to investigate the location and characteristics of the source region. Finally, the location of the TMR source region is demonstrated by direct measurement.

  16. Cosmogenic helium in a terrestrial igneous rock

    NASA Technical Reports Server (NTRS)

    Kurz, M. D.

    1986-01-01

    New helium isotopic measurements on samples from the Kula formation of Haleakala volcano of Hawaii are presented that are best explained by an in situ cosmogenic origin for a significant fraction of the He-3. Results from crushing and stepwise heating experiments, and consideration of the exposure age of the sample at the surface and the cosmic ray fluxes strongly support this hypothesis. Although crustal cosmogenic helium has been proposed previously, this represents its first unambiguous identification in a terrestrial sample.

  17. A toy terrestrial carbon flow model

    NASA Technical Reports Server (NTRS)

    Parton, William J.; Running, Steven W.; Walker, Brian

    1992-01-01

    A generalized carbon flow model for the major terrestrial ecosystems of the world is reported. The model is a simplification of the Century model and the Forest-Biogeochemical model. Topics covered include plant production, decomposition and nutrient cycling, biomes, the utility of the carbon flow model for predicting carbon dynamics under global change, and possible applications to state-and-transition models and environmentally driven global vegetation models.

  18. Testbed for Satellite and Terrestrial Interoperability (TSTI)

    NASA Technical Reports Server (NTRS)

    Gary, J. Patrick

    1998-01-01

    Various issues associated with the "Testbed for Satellite and Terrestrial Interoperability (TSTI)" are presented in viewgraph form. Specific topics include: 1) General and specific scientific technical objectives; 2) ACTS experiment No. 118: 622 Mbps network tests between ATDNet and MAGIC via ACTS; 3) ATDNet SONET/ATM gigabit network; 4) Testbed infrastructure, collaborations and end sites in TSTI based evaluations; 5) the Trans-Pacific digital library experiment; and 6) ESDCD on-going network projects.

  19. Experimental Tribulus terrestris poisoning in goats

    Microsoft Academic Search

    M. R. Aslani; A. R. Movassaghi; M. Mohri; V. Ebrahim-pour; A. N. Mohebi

    2004-01-01

    Seven, 1–2-year-old native goats were fed dried Tribulus terrestris from Sabzevar district of Khorasan province for 8 weeks. Two goats showed clinical signs of toxicity including weight loss, depression, ruminal stasis, icterus and elevation of body temperature. Haematological and biochemical trails revealed a declining of packed cell volume (PCV) and plasma total protein and elevation of total and direct bilirubin,

  20. Comparison Charts of Geological Processes: Terrestrial Planets

    NSDL National Science Digital Library

    This chart presents information on the geological processes (volcanism, impact cratering, tectonics, and gradation) that have affected the Earth, Moon, and the terrestrial planets. Students compare the effects these processes have had on the Moon and planets. There is also a blank chart and a sheet of notes on the geological processes that may be used in conjunction with this chart. This chart is one of the activities for the Exploring Planets in the Classroom's Introduction to the Solar System.

  1. Long-period solar-terrestrial variability

    SciTech Connect

    Sonett, C.P. (USAF, Geophysics Laboratory, Hanscom AFB, MA (United States))

    1991-01-01

    Studies aimed at extending the record of solar-terrestrial variability to longer periods are discussed in a critical review of US research from the period 1987--1990. Sections are devoted to the sunspot index, radioactive carbon studies, a potential climate connection between radiocarbon changes and the solar irradiance cycle, Be-10 studies, geological laminae, solar neutrino counts, and the construction of data sets. Also included is a selective bibliography. 66 refs.

  2. Global change and terrestrial hydrology - A review

    NASA Technical Reports Server (NTRS)

    Dickinson, Robert E.

    1991-01-01

    This paper reviews the role of terrestrial hydrology in determining the coupling between the surface and atmosphere. Present experience with interactive numerical simulation is discussed and approaches to the inclusion of land hydrology in global climate models ae considered. At present, a wide range of answers as to expected changes in surface hydrology is given by nominally similar models. Studies of the effects of tropical deforestation and global warming illustrate this point.

  3. Lunar and Planetary Science XXXV: Terrestrial Planets

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The session "Terrestrial Planets: included:Lunar Soils May Tell Us When the Geomagnetic Field First Appeared; Metal-Silicate Segregation in Deforming Dunitic Rocks: Applications to Core Formation in Europa and Ganymede; Diamond Formation in Core Segregation Experiments; The Effect of Pressure on Potassium Partitioning Between Metallic Liquid and Silicate Melt; Reduction of W, Mn, and Fe, During High-Temperature Vaporization; Micrometeoritic Neon in the Earth s Mantle ; and New Analyses of Diverse Hadean Zircon Inclusions from Jack Hills.

  4. Research of remote control for Chinese Antarctica Telescope based on iridium satellite communication

    NASA Astrophysics Data System (ADS)

    Xu, Lingzhe; Yang, Shihai

    2010-07-01

    Astronomers are ever dreaming of sites with best seeing on the Earth surface for celestial observation, and the Antarctica is one of a few such sites only left owing to the global air pollution. However, Antarctica region is largely unaccessible for human being due to lacking of fundamental living conditions, travel facilities and effective ways of communication. Worst of all, the popular internet source as a general way of communication scarcely exists there. Facing such a dilemma and as a solution remote control and data transmission for telescopes through iridium satellite communication has been put forward for the Chinese network Antarctic Schmidt Telescopes 3 (AST3), which is currently under all round research and development. This paper presents iridium satellite-based remote control application adapted to telescope control. The pioneer work in China involves hardware and software configuration utilizing techniques for reliable and secure communication, which is outlined in the paper too.

  5. Terrestrial water fluxes dominated by transpiration.

    PubMed

    Jasechko, Scott; Sharp, Zachary D; Gibson, John J; Birks, S Jean; Yi, Yi; Fawcett, Peter J

    2013-04-18

    Renewable fresh water over continents has input from precipitation and losses to the atmosphere through evaporation and transpiration. Global-scale estimates of transpiration from climate models are poorly constrained owing to large uncertainties in stomatal conductance and the lack of catchment-scale measurements required for model calibration, resulting in a range of predictions spanning 20 to 65 per cent of total terrestrial evapotranspiration (14,000 to 41,000 km(3) per year) (refs 1, 2, 3, 4, 5). Here we use the distinct isotope effects of transpiration and evaporation to show that transpiration is by far the largest water flux from Earth's continents, representing 80 to 90 per cent of terrestrial evapotranspiration. On the basis of our analysis of a global data set of large lakes and rivers, we conclude that transpiration recycles 62,000 ± 8,000 km(3) of water per year to the atmosphere, using half of all solar energy absorbed by land surfaces in the process. We also calculate CO2 uptake by terrestrial vegetation by connecting transpiration losses to carbon assimilation using water-use efficiency ratios of plants, and show the global gross primary productivity to be 129 ± 32 gigatonnes of carbon per year, which agrees, within the uncertainty, with previous estimates. The dominance of transpiration water fluxes in continental evapotranspiration suggests that, from the point of view of water resource forecasting, climate model development should prioritize improvements in simulations of biological fluxes rather than physical (evaporation) fluxes. PMID:23552893

  6. Regulatory mechanisms in Thielavia terrestris. Final report

    SciTech Connect

    Tuse, D.; Hokama, L.

    1982-03-15

    Thielavia terrestris is a filamentous ascomycete originally discovered and identified as Allescheria terrestris by Apinis (1963). Strain S-16 was isolated from a soil sample in California and found to grow at temperatures as high as 50/sup 0/C. The fungus produces a complete cellulase system that enables it to degrade native, crystalline cellulose to glucose. The enzymes display high heat and pH stability and an optimum temperature for hydrolysis of 65/sup 0/C, making it attractive for the eventual commercial conversion of cellulose into fuel and chemicals. We report on the enzyme activity of Thielavia terrestris S-16, the effects of medium composition and carbon source on enzyme production, the growth of the organism at different temperatures, the extracellular aryl-..beta..-glucosidase activitiy as a function of incubation temperature, the effects of small-molecular-weight metabolic regulators and membrane-active antibiotics on the cell-associated and extracellular enzyme levels, and the methods used in an attempt to find plasmids.

  7. INMARSAT's personal communicator system

    NASA Technical Reports Server (NTRS)

    Hart, Nick; Haugli, HANS-C.; Poskett, Peter; Smith, K.

    1993-01-01

    Inmarsat has been providing near global mobile satellite communications since 1982 and Inmarsat terminals are currently being used in more than 130 countries. The terminals have been reduced in size and cost over the years and new technology has enabled the recent introduction of briefcase sized personal telephony terminals (Inmarsat-M). This trend continues and we are likely to see Inmarsat handheld terminals by the end of the decade. These terminals are called Inmarsat-P and this paper focuses on the various elements required to support a high quality service to handheld terminals. The main system elements are: the handheld terminals; the space segment with the associated orbits; and the gateways to terrestrial networks. It is both likely and desirable that personal handheld satellite communications will be offered by more than one system provider and this competition will ensure strong emphasis on service quality and cost of ownership. The handheld terminals also have to be attractive to a large number of potential users, and this means that the terminals must be small enough to fit in a pocket. Battery lifetime is another important consideration, and this coupled with radiation safety requirements limits the maximum radiated EIRP. The terminal G/T is mainly constrained by the gain of the omnidirectional antenna and the noise figure of the RF front end (including input losses). Inmarsat has examined, with the support of industry, a number of Geosynchronous (GSO), Medium Earth Orbit (MEO) and Low Earth Orbit (LEO) satellite options for the provision of a handheld mobile satellite service. This paper describes the key satellite and orbit parameters and tradeoffs which affect the overall quality of service and the space segment costing. The paper also stresses not only the importance of using and sharing the available mobile frequency band allocations efficiently, but also the key considerations affecting the choice of feeder link bands. The design of the gateways and the terrestrial network is critical to the overall viability of the service, and this paper also examines the key technical parameters associated with the Land Earth Stations (LES), which act as gateways into the Public Switched Telephone Network (PSTN). These not only include the design tradeoffs associated with the LES, but also the different terrestrial network interface options. The paper concludes with a brief description of the satellite propagation conditions associated with the use of handheld terminals. It describes how the handheld results in a number of propagation impairments which are not common to the previous measurements associated with vehicle mounted antennas. These measurements indicate that there is a complex tradeoff between link margin and the elevation angle to the satellite which has a significant impact on the space segment requirements and costing.

  8. Canine communication.

    PubMed

    Engel, Marcus

    2011-01-01

    A Seeing Eye dog handler discusses nonverbal, nonvocal communication between human and animal. Each gesture and nonverbal element from dog to master and vice versa shows intricate patterns of communication that can relate to patient care. PMID:22403859

  9. Transmission Communication

    E-print Network

    Chen, Sheng

    ELEC3028 Digital Transmission -- MODEM S Chen Digital Communication System . Purpose: communicate: rate, quality # spectral bandwidth requirement . Major components: CODEC, MODEM and channel modulation input output CODEC MODEM Medium 1 #12; ELEC3028 Digital Transmission -- MODEM S Chen Digital

  10. Lightwave Communications.

    ERIC Educational Resources Information Center

    Rheam, Harry

    1993-01-01

    Describes simple and inexpensive labs for introducing students to fiber optic communications. Students investigate light as a carrier wave; look into the difficulties associated with "light" communication; and learn about modulation, optical fibers, and critical angles. (PR)

  11. Data communications

    SciTech Connect

    Preckshot, G.G. [Lawrence Livermore National Lab., CA (United States)

    1993-08-01

    The purpose of this paper is to recommend regulatory guidance for reviewers examining computer communication systems used in nuclear power plants. The recommendations cover three areas important to these communications systems: system design, communication protocols, and communication media. The first area, system design, considers three aspects of system design--questions about architecture, specific risky design elements or omissions to look for in designs being reviewed, and recommendations for multiplexed data communication systems used in safety systems. The second area reviews pertinent aspects of communication protocol design and makes recommendations for newly designed protocols or the selection of existing protocols for safety system, information display, and non-safety control system use. The third area covers communication media selection, which differs significantly from traditional wire and cable. The recommendations for communication media extend or enhance the concerns of published IEEE standards about three subjects: data rate, imported hazards and maintainability.

  12. Chemical Communication

    NSDL National Science Digital Library

    0000-00-00

    A concise lesson about chemical communication in insects covering both semio and info chemicals. The site includes a short video of grape root borer moths using sex pheromone. Further links on the take the user to visual and auditory communication.

  13. Communication (action with communicative content).

    PubMed

    Russo, M T

    2010-01-01

    The term Communication generally designate the transmission of a message of concepts, feelings or needs from a speaker to a receiver by means of verbal or no verbal language. The pragmatic approach to human communication has put in evidence a further implication of this concept: every behaviour therefore has a value even when it is not intentional. Recently, a more dynamic concept of communication has been elaborated where communication means communicative action. This interpretation is the starting point for the theory of the "communicative acting" and subsequently of the so called discourse ethic elaborated by J. Habermas. PMID:20499038

  14. Efficient Integration of IP-Based Terrestrial and Satellite Systems: ARQ Techniques and InterSegment Handover

    Microsoft Academic Search

    Ernestina Cianca; Michele Angelaccio; Michele Luglio; Marina Ruggieri; Pasquale Daponte; Roberto Lojacono; Ramjee Prasad

    2002-01-01

    A satellite communication system is an excellent candidate toprovide broadband integrated Internet services to globallyscattered users. The inter-operation between a satellite systemand the existing terrestrial Internet infrastructure introducesnew challenges at different layers. Automatic Repeat reQuest (ARQ)techniques have been introduced at radio link layer to improve theperformance of Transport Control Protocol (TCP)\\/IP over wirelessterrestrial links, but these techniques are usually dismissed

  15. Hydrolytic microbial communities in terrestrial ecosystems

    NASA Astrophysics Data System (ADS)

    Manucharova, Natalia; Chernov, Timofey; Kolcova, Ekaterina; Zelezova, Alena; Lukacheva, Euhenia; Zenova, Galina

    2014-05-01

    Hydrolytic microbial communities in terrestrial ecosystems Manucharova N.A., Chernov T.I., Kolcova E.M., Zelezova A.D., Lukacheva E.G. Lomonosov Moscow State University, Russia Vertical differentiation of terrestrial biogeocenoses is conditioned by the formation of vertical tiers that differ considerably in the composition and structure of microbial communities. All the three tiers, phylloplane, litter and soil, are united by a single flow of organic matter, and are spatially separated successional stages of decomposition of organic substances. Decomposition of organic matter is mainly due to the activity of microorganisms producing enzymes - hydrolase and lyase - which destroy complex organic compounds. Application of molecular biological techniques (FISH) in environmental studies provides a more complete information concerning the taxonomic diversity and potential hydrolytic activity of microbial complexes of terrestrial ecosystems that exist in a wide range of environmental factors (moisture, temperature, redox potential, organic matter). The combination of two molecular biological techniques (FISH and DGGE-analysis of fragments of gene 16S rRNA total amplificate) enables an informative assessment of the differences in the structure of dominant and minor components of hydrolytic complexes formed in different tiers of terrestrial ecosystems. The functional activity of hydrolytic microbial complexes of terrestrial ecosystems is determined by the activity of dominant and minor components, which also have a high gross enzymatic activity. Degradation of biopolymers in the phylloplane is mainly due to the representatives of the Proteobacteria phylogenetic group (classes alpha and beta). In mineral soil horizons, the role of hydrolytic representatives of Firmicutes and Actinobacteria increases. Among the key environmental parameters that determine the functional activity of the hydrolytic (chitinolytic) complex of soil layer (moisture, nutrient supply, successional time), the most significant one is moisture. Moisture levels providing maximum activity of a hydrolytic microbial complex depend on the soil type. Development of a hydrolytic microbial complex occurs in a very wide moisture range - from values close to field capacity to those close to the wilting moisture point. The functional role of mycelial actinobacteria in the metabolism of chitin consists, on the one hand, in active decomposition of this biopolymer, and on the other hand, in the regulation of microbial hydrolytic complex activity through the production of biologically active regulatory metabolites, which occurs in a wide range of environmental parameters (moisture, temperature, organic matter, successional time). Experimental design is applicable to identify in situ optimal values of environmental factors that considerably affect the functional parameters of hydrolytic microbial complexes.

  16. Cultural Communications.

    ERIC Educational Resources Information Center

    Armas, Jose

    It is too often taken for granted that the communication process with culturally different children takes place as readily as it might with children from Anglo cultures. Most teachers receive training in verbal and formal communication skills; children come to school with nonverbal and informal communication skills. This initially can create…

  17. Communication Speaks

    ERIC Educational Resources Information Center

    Kinman, Robin Lynn

    2010-01-01

    When the author recently turned her attention to the National Council of Teachers of Mathematics (NCTM) "Principles and Standards," she was startled to see communication as key. She adjusted her teaching to meet the NCTM Communication Standard and promote communication in her classroom by providing a safe environment, developing discourse and…

  18. Communication, Communication, Communication! Growth through Laboratory Instructing

    ERIC Educational Resources Information Center

    Peterson, Jamie J.; DeAngelo, Samantha; Mack, Nancy; Thompson, Claudia; Cooper, Jennifer; Sesma, Arturo, Jr.

    2014-01-01

    This study examined gains undergraduate students made in their communication and collaboration skills when they served as peer teachers, i.e., laboratory instructors (LIs), for a General Psychology laboratory. Self-ratings of communication and collaboration skills were completed before and after teaching the laboratory. When compared to before the…

  19. Workshop on Oxygen in the Terrestrial Planets

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This volume contains abstracts that have been accepted for presentation at the Workshop on Oxygen in the Terrestrial Planets, July 20-23,2004, Santa Fe, New Mexico. The contents include: 1) Experimental Constraints on Oxygen and Other Light Element Partitioning During Planetary Core Formation; 2) In Situ Determination of Fe(3+)/SigmaFe of Spinels by Electron Microprobe: An Evaluation of the Flank Method; 3) The Effect of Oxygen Fugacity on Large-Strain Deformation and Recrystallization of Olivine; 4) Plagioclase-Liquid Trace Element Oxygen Barometry and Oxygen Behaviour in Closed and Open System Magmatic Processes; 5) Core Formation in the Earth: Constraints from Ni and Co; 6) Oxygen Isotopic Compositions of the Terrestrial Planets; 7) The Effect of Oxygen Fugacity on Electrical Conduction of Olivine and Implications for Earth s Mantle; 8) Redox Chemical Diffusion in Silicate Melts: The Impact of the Semiconductor Condition; 9) Ultra-High Temperature Effects in Earth s Magma Ocean: Pt and W Partitioning; 10) Terrestrial Oxygen and Hydrogen Isotope Variations: Primordial Values, Systematics, Subsolidus Effects, Planetary Comparisons, and the Role of Water; 11) Redox State of the Moon s Interior; 12) How did the Terrestrial Planets Acquire Their Water?; 13) Molecular Oxygen Mixing Ratio and Its Seasonal Variability in the Martian Atmosphere; 14) Exchange Between the Atmosphere and the Regolith of Mars: Discussion of Oxygen and Sulfur Isotope Evidence; 15) Oxygen and Hydrogen Isotope Systematics of Atmospheric Water Vapor and Meteoric Waters: Evidence from North Texas; 16) Implications of Isotopic and Redox Heterogeneities in Silicate Reservoirs on Mars; 17) Oxygen Isotopic Variation of the Terrestrial Planets; 18) Redox Exchanges in Hydrous Magma; 19) Hydrothermal Systems on Terrestrial Planets: Lessons from Earth; 20) Oxygen in Martian Meteorites: A Review of Results from Mineral Equilibria Oxybarometers; 21) Non-Linear Fractionation of Oxygen Isotopes Implanted in Lunar Metal Grains: Solar, Lunar or Terrestrial Origin? 22) Isotopic Zoning in the Inner Solar System; 23) Redox Conditions on Small Bodies; 24) Determining the Oxygen Fugacity of Lunar Pyroclastic Glasses Using Vanadium Valence - An Update; 25) Mantle Redox Evolution and the Rise of Atmospheric O2; 26) Variation of Kd for Fe-Mg Exchange Between Olivine and Melt for Compositions Ranging from Alkaline Basalt to Rhyolite; 27) Determining the Partial Pressure of Oxygen (PO,) in Solutions on Mars; 28) The Influence of Oxygen Environment on Kinetic Properties of Silicate Rocks and Minerals; 29) Redox Evolution of Magmatic Systems; 30) The Constancy of Upper Mantlefo, Through Time Inferred from V/Sc Ratios in Basalts: Implications for the Rise in Atmospheric 0 2; 31) Nitrogen Solubility in Basaltic Melt. Effects of Oxygen Fugacity, Melt Composition and Gas Speciation; 32) Oxygen Isotope Anomalies in the Atmospheres of Earth and Mars; 33) The Effect of Oxygen Fugacity on Interdiffusion of Iron and Magnesium in Magnesiowiistite 34) The Calibration of the Pyroxene Eu-Oxybarometer for the Martian Meteorites; 35) The Europium Oxybarometer: Power and Pitfalls; 36) Oxygen Fugacity of the Martian Mantle from PigeoniteMelt Partitioning of Samarium, Europium and Gadolinium; 37) Oxidation-Reduction Processes on the Moon: Experimental Verification of Graphite Oxidation in the Apollo 17 Orange Glasses; 38) Oxygen and Core Formation in the Earth; 39) Geologic Record of the Atmospheric Sulfur Chemistry Before the Oxygenation of the Early Earth s Atmosphere; 40) Comparative Planetary Mineralogy: V/(CrCAl) Systematics in Chromite as an Indicator of Relative Oxygen Fugacity; 41) How Well do Sulfur Isotopes Constrain Oxygen Abundance in the Ancient Atmospheres? 42) Experimental Constraints on the Oxygen Isotope (O-18/ O-16) Fractionation in the Ice vapor and Adsorbant vapor Systems of CO2 at Conditions Relevant to the Surface of Mars; 43) Micro-XANES Measurements on Experimental Spinels andhe Oxidation State of Vanadium in Spinel-Melt Pairs; 44) Testing the Magma Ocean Hypothesis Using

  20. Adaptive Control Method for Massive and Intensive Traffic in Communication-Broadcasting Integrated Services

    Microsoft Academic Search

    Hideyuki KOTO; Hiroki FURUYA; H. Nakamura

    2005-01-01

    This paper proposes an adaptive control method of delayed transmission for massive and intensive telecommunication traffic expected in communication-broadcasting integrated services. It furthermore presents quantitative evaluation of the proposed method through computer simulations and experiments using a test bed. Communication-broadcasting integrated services, which have been started by the terrestrial digital broadcasting, give rise to the massive and intensive traffic induced

  1. A New Satellite Communication System Integrated into Public Switched Networks. - DYANET

    Microsoft Academic Search

    Masahumi Ohnuki; Masahiro Umehira; Hiroshi Nakashima; Shuzo Kato

    1992-01-01

    A system concept of a common alternative routing system is proposed for reducing total network costs by integrating satellite communications into public-switched networks, where satellite systems carry overflow traffic from terrestrial systems through common satellite channels. This concept has been realized by a satellite communication system called DYANET (dynamic channel assigning and routing satellite aided digital networks), which provides trunk

  2. An advanced satellite communication system for ISDN subscriber and trunk applications - DYANET-II

    Microsoft Academic Search

    Toru Otsu; Masahiro Umehira; Masafumi Onuki; Hiroshi Nakashima

    1992-01-01

    This paper describes an advanced satellite communication system for ISDN subscriber and trunk applications that is integrated into a terrestrial ISDN. The system concept of DYANET (DYnamic channel Assigning and routing satellite aided digital NETwork) has been extended to a new platform called DYANET-II which allows satellite communications to be applied to ISDN subscriber lines as well as trunk circuits.

  3. Smart Grid Development Issues for Terrestrial and Space Applications

    NASA Technical Reports Server (NTRS)

    Soeder, James F.

    2014-01-01

    The development of the so called Smart Grid has as many definitions as individuals working in the area. Based on the technology or technologies that are of interest, be it high speed communication, renewable generation, smart meters, energy storage, advanced sensors, etc. they can become the individual defining characteristic of the Smart Grid. In reality the smart grid encompasses all of these items and quite at bit more. This discussion attempts to look at what the needs are for the grid of the future, such as the issues of increased power flow capability, use of renewable energy, increased security and efficiency and common power and data standards. It also shows how many of these issues are common with the needs of NASA for future exploration programs. A common theme to address both terrestrial and space exploration issues is to develop micro-grids that advertise the ability to enable the load leveling of large power generation facilities. However, for microgrids to realize their promise there needs to a holistic systems approach to their development and integration. The overall system integration issues are presented along with potential solution methodologies.

  4. Smart Grid Development Issues for Terrestrial and Space Applications

    NASA Technical Reports Server (NTRS)

    Soeder, James F.

    2011-01-01

    The development of the so called Smart Grid has as many definitions as individuals working in the area. Based on the technology or technologies that are of interest, be it high speed communication, renewable generation, smart meters, energy storage, advanced sensors, etc. they can become the individual defining characteristic of the Smart Grid. In reality the smart grid encompasses all of these items and quite at bit more. This discussion attempts to look at what the needs are for the grid of the future, such as the issues of increased power flow capability, use of renewable energy, increased security and efficiency and common power and data standards. It also shows how many of these issues are common with the needs of NASA for future exploration programs. A common theme to address both terrestrial and space exploration issues is to develop micro-grids that advertise the ability to enable the load leveling of large power generation facilities. However, for microgrids to realize their promise there needs to a holistic systems approach to their development and integration. The overall system integration issues are presented along with potential solution methodologies.

  5. Land mobile communications satellite mission (LAMOCOSAMIS) Task 1: Market study

    NASA Astrophysics Data System (ADS)

    1985-12-01

    Land mobile communication service demand in Europe and the Mediterranean basin in the years 1995-2005 was estimated. A traffic model was derived. There is an exploding demand for land mobile communications in Europe, with overwhelming preference for two way telephone services. The users survey shows a surprising lack of sensitivity to prices and tariffs, which widely contributed to the preeminence of the needs for telephone services. This demand justifies that every effort be made to develop as fast as possible a compatible pan-European terrestrial mobile system. If a large proportion of the needs may be satisfied by terrestrial mobile system solutions, the potential remaining needs for telephony, outside of the presently planned terrestrial mobile, which can be served only by satellite, even under the pessimistic economic scenario and high cost/tariff assumptions, requires a number of equivalent telephone circuits which cannot be achieved with available state of the art technology.

  6. Communication architecture of an early warning system

    NASA Astrophysics Data System (ADS)

    Angermann, M.; Guenther, M.; Wendlandt, K.

    2010-11-01

    This article discusses aspects of communication architecture for early warning systems (EWS) in general and gives details of the specific communication architecture of an early warning system against tsunamis. While its sensors are the "eyes and ears" of a warning system and enable the system to sense physical effects, its communication links and terminals are its "nerves and mouth" which transport measurements and estimates within the system and eventually warnings towards the affected population. Designing the communication architecture of an EWS against tsunamis is particularly challenging. Its sensors are typically very heterogeneous and spread several thousand kilometers apart. They are often located in remote areas and belong to different organizations. Similarly, the geographic spread of the potentially affected population is wide. Moreover, a failure to deliver a warning has fatal consequences. Yet, the communication infrastructure is likely to be affected by the disaster itself. Based on an analysis of the criticality, vulnerability and availability of communication means, we describe the design and implementation of a communication system that employs both terrestrial and satellite communication links. We believe that many of the issues we encountered during our work in the GITEWS project (German Indonesian Tsunami Early Warning System, Rudloff et al., 2009) on the design and implementation communication architecture are also relevant for other types of warning systems. With this article, we intend to share our insights and lessons learned.

  7. Application of the Iridium Satellite System to Aeronautical Communications

    NASA Technical Reports Server (NTRS)

    Kerczewski, Robert J.; Meza, Mike; Gupta, Om

    2008-01-01

    The next generation air transportation system will require greater air-ground communications capacity to accommodate more air traffic with increased safety and efficiency. Communications will remain primarily terrestrially based, but satellite communications will have an increased role. Inmarsat s aeronautical services have been approved and are in use for aeronautical safety communications provided by geostationary satellites. More recently the approval process for the Iridium low earth orbit constellation is nearing completion. The current Iridium system will be able to provide basic air traffic services communications suitable for oceanic, remote and polar regions. The planned second generation of the Iridium system, called Iridium NEXT, will provide enhanced capabilities and enable a greater role in the future of aeronautical communications. This paper will review the potential role of satellite communications in the future of air transportation, the Iridium approval process and relevant system testing, and the potential role of Iridium NEXT.

  8. System-wide information management for aeronautical communications

    Microsoft Academic Search

    M. S. Taylor

    2004-01-01

    Interactions among airborne and terrestrial elements in an aeronautical environment may be enhanced by using common mechanisms for data transport and information management. These mechanisms can support a variety of applications, such as controller-pilot communications, surveillance, scheduling, traffic management, airline operations and others that vary widely in their respective requirements for security, performance and availability. This work presents an architectural

  9. Prediction of tropospheric multipath effects on microwave communication system performance

    Microsoft Academic Search

    H Vasseur; D Vanhoenacker-Janvier

    1996-01-01

    A simple deterministic model is proposed to represent in a realistic way the time evolution of nocturnal refractive layers in the lower troposphere. It enables simulations of the multipath fading effects induced on both microwave terrestrial links and low-elevation satellite paths. It offers an efficient means for characterising the transmission channel and predicting the error performances of radio communication systems

  10. Towards Flexibility and Accuracy in Space DTN Communications

    E-print Network

    Tsaoussidis, Vassilis

    ---Routing Protocols. General Terms Management, Performance. Keywords Delay Tolerant Networking, Interplanetary are characterized by long propagation delays and intermittent but scheduled connectivity. In this context, Delay-Tolerant-planetary, deep space, near- Earth and terrestrial communications, forming a flexible and secure networking

  11. Assessing the Response of Terrestrial Ecosystems to Potential Changes in Precipitation

    NSDL National Science Digital Library

    JAKE F. WELTZIN, MICHAEL E. LOIK, SUSANNE SCHWINNING, DAVID G. WILLIAMS, PHILIP A. FAY, BRENT M. HADDAD, JOHN HARTE, TRAVIS E. HUXMAN, ALAN K. KNAPP, GUANGHUI LIN, WILLIAM T. POCKMAN, M. REBECCA SHAW, ERIC E. SMALL, MELINDA D. SMITH, STANLEY D. SMITH, DAVID T. TISSUE, and JOHN C. ZAK (; )

    2003-09-01

    This peer-reviewed article from Bioscience journal is on the effects of changes in precipitation to the terrestrial ecosystem. Changes in Earth's surface temperatures caused by anthropogenic emissions of greenhouse gases are expected to affect global and regional precipitation regimes. Interactions between changing precipitation regimes and other aspects of global change are likely to affect natural and managed terrestrial ecosystems as well as human society. Although much recent research has focused on assessing the responses of terrestrial ecosystems to rising carbon dioxide or temperature, relatively little research has focused on understanding how ecosystems respond to changes in precipitation regimes. Here we review predicted changes in global and regional precipitation regimes, outline the consequences of precipitation change for natural ecosystems and human activities, and discuss approaches to improving understanding of ecosystem responses to changing precipitation. Further, we introduce the Precipitation and Ecosystem Change Research Network (PrecipNet), a new interdisciplinary research network assembled to encourage and foster communication and collaboration across research groups with common interests in the impacts of global change on precipitation regimes, ecosystem structure and function, and the human enterprise.

  12. Teppeki, selective insecticide about Bombus terrestris.

    PubMed

    Fanigliulo, Angela; Filì, Vittorio; Pacella, Rosa; Comes, Soccorsa; Crescenzi, Aniello

    2009-01-01

    At a time when a highly controversial debate about the causes of the widespread deaths of bees is taking place all over Europe, which accused the agriculture and its practices with particular reference to the harmful effects of some insecticides, it seems important to point out as another insecticide, the Teppeki, can be selective about bumble and have a good compatibility with the activity of the apiaries. This insecticide has the active ingredient flonicamid (500 g/kg) belonging to a new chemical class, called pyridinecarboxamides: the product works systemic and is known as having a long lasting efficacy against all important aphid species. Bioagritest test facility of Pignola (PZ, Italy) has conducted in two successive production cycles an experimental trial on a tomato hydroponic cultivation within the Agricola Bonsai farm in Sibari (CS, Italy), whose objective was to measure the selectivity of flonicamid on Bombus terrestris, insects playing an important role in the pollination of certain species grown in greenhouse such as Tomato, Eggplant, Pepper and Cucumber. On the pollinated flower B. terrestris leaves some trace of its visit, a typical dark trademark: on the detection of the marking of flowers was based the testing program conducted by Bioagritest. Two thesis were compared: A, standard) treatment with a foliar insecticide, the neonicotinoide acetamiprid, normally used for control of aphids and whiteflies (unlike other neonicotinoides--imidacloprid and thiametoxam--quite selective about B. terrestris) and B, Teppeki) foliar treatment with Teppeki, to the maximum dose indicated on the label. The experimental design included the use of randomized blocks with 4 repetitions (4 plots/thesis with 100 plants each). In every thesis six B. terrestris hives were placed 2 days before treatment: the respective holes remained closed during the treatment and the 12 following hours. In order to verify the pollination, by the detection of the flower marking, 2 flowers per plant were observed, for a total of 200 flowers per plot. The measurements were made on the 3rd (I relief) and 8th day (II relief) after treatment. Statistical analysis was performed by the use of XLSTAT data analysis and statistical software. The analysis of collected data shows that flonicamid has a minor effect of interference with the activity of pollination by B. terrestris, compared to the standard used. 14 days after treatment, 3 hives per thesis were inspected in order to verify the status of the colonies (adults, larvae, eggs, pollen). The colonies appeared generally homogeneous as concerning the number of alive adults--100 for each--all at the end of the development cycle. There was no dead adult. Two colonies, one for thesis, presented evidence of eggs. All colonies had low stocks of pollen. Ultimately, treatment with Teppeki has not given any acute effect on B. terrestris, nor any effect of interference in respect of its pollination activity. PMID:20222598

  13. Terrestrial Reference Frame from GPS and SLR

    NASA Astrophysics Data System (ADS)

    Weiss, Jan; Bertiger, Willy; Desai, Shailen; Haines, Bruce; Sibois, Aurore

    2015-04-01

    We present strategies for realizing the terrestrial reference frame (TRF) using tracking data from terrestrial GPS receivers alone and in tandem with the GRACE and LAGEOS satellites. We generate solutions without apriori ties to the International Terrestrial Reference Frame (ITRF). Our approach relies on processing multi-day orbit arcs to take advantage of the satellite dynamics, GPS receiver and transmitter calibrations derived from low-Earth orbiter (LEO) data, and estimation strategies tuned for realizing a stable and accurate TRF. We furthermore take advantage of the geometric diversity provided by GPS tracking from GRACE, and explore the impacts of including ground-based satellite laser range (SLR) measurements to LAGEOS-1 and -2 with local ties relating the two geodetic techniques. We process data from 2003-2014 and compute Helmert transformations relative to ITRF/IGb08. With GPS alone we achieve a 3D origin offset and rate of <7 mm and <1 mm/yr, and reduce the offset to <4 mm when GRACE is included in the global solutions. Scale bias and rate are 3.1 ppb and 0.01 ppb/yr in either solution. Including SLR tracking from 11 ground stations to the LAGEOS satellites from 2012-2014 yields a reduction in scale bias of 0.5-1.0 ppb depending on the weight assigned to the SLR measurements. However, scatter is increased due to the relatively sparse SLR tracking network. We conclude with approaches for improving the TRF realized from GPS and SLR combined at the measurement level.

  14. Terrestrial solar arrays with integral glass construction

    NASA Technical Reports Server (NTRS)

    Younger, P. R.; Kreisman, W. S.; Landis, G. A.; Kirkpatrick, A. R.; Holtze, R. F.

    1978-01-01

    An excellent encapsulation system for a terrestrial solar array can be formed using two sheets of glass. Superior technical character, very low cost and simple assembly can result if the active components and the glass sheets are integrally bonded together such that the array is hermetically sealed without employing organic encapsulation materials. Such an approach is being developed using electrostatic bonding. Status of this development is described. Functioning integral glass test modules have been fabricated and subjected to environmental testing. Results have been excellent.

  15. Terrestrial planet composition: simulation and observation

    NASA Astrophysics Data System (ADS)

    Carter-Bond, J.; Bolmont, E.; Raymond, S.

    2014-03-01

    As direct detection and examination of terrestrial exoplanets is not yet possible, we must persue alternative methods to constarin the types of planets likely to be found within extrasolar planetary systems and thus guide future missions. Such studies cannot be undertaken by transit surveys. Instead, secondary sources must be utilized. In addition to simultions of terrestrial planet formation, based on spectroscopic observations of known stars, observations of polluted white dwarfs (e.g. Jura, M., & Xu, S. (2012); Gaensicke et al., (2013)) and simulations of the pollution of migrating gas giants may be utilized to determine the composition of solid bodies withn extrasolar planetary systems. Observations of polluted white dwarfs (e.g. Jura, M., & Xu, S. (2012); Gaensicke et al., (2013)) will be compared to simulations of the bulk composition of terrestrial planets (Carter-Bond et al. (2012)). Combining dynamical simulations of Carter-Bond et al. (2012) and Raymond et al. (2006) with spectrally-derived abundances for 15 planet-forming elements (H, C, N, O, Na, Mg, Al, Si, P, S, Ca, Ti, Cr, Fe and Ni), bulk compositions for simulated terrestrial planets have been obtained. This is the first time that compositional simulations can be compared with observations (albeit of a proxy for solid composition) and will be crucial for placing constraints on both the true diversity of planetary compositions expected to exist in extrasolar planetary systems and the simulations currently utilized. Simulations of the change in composition resulting from pollution of a gas giant as it migrates through a planetary system will also be presented. These simulations represent an as-yet untested approach to determining the solid composition within a planetary system. By simulating the amount and composition of material accreted by the gas giant (following Carter-Bond et al. (2012)), we will be able to determine what effect, if any, the accretion of solid material during migration has on giant planet composition. This study represents the first attempt at untangling what fraction of the observed composition is primordial and what fraction has been accreted and may, ultimately, provide further limitation on the composition of solids within extrasolar planetary systems. Such a study is especially timely, given the rising number of spectral observations of transiting giant planets and their unusual implications (e.g. Madhusudhan et al. (2011)).

  16. Tectonic history of the terrestrial planets

    NASA Technical Reports Server (NTRS)

    Solomon, Sean C.

    1990-01-01

    It is impossible in a single brief summary to convey the full range of research results that have come from this project over the last 13 years. The sweep of subjects covered ranges widely over the broad areas of the thermal and tectonic evolution of the terrestrial planets. A full list of all publications supported by this grant is presented. The list includes 48 published journal articles, 2 papers currently in press, 3 chapters of books, 4 M.I.T. theses, 1 technical report, and 107 published abstracts and extended abstracts. All of these publications were submitted separately to NASA at the time of publication or submission.

  17. Two new furostanol saponins from Tribulus terrestris.

    PubMed

    Xu, Ya-Juan; Xu, Tun-Hai; Zhou, Hai-Ou; Li, Bo; Xie, Sheng-Xu; Si, Yun-Shan; Liu, Yue; Liu, Tong-Hua; Xu, Dong-Ming

    2010-05-01

    Two new furostanol saponins were isolated from the fruits of Tribulus terrestris L. Their structures were established as 26-O-beta-D-glucopyranosyl-(25S)-5alpha-furost-20(22)-en-3beta,26-diol-3-O-alpha-L-rhamnopyranosyl-(1 --> 2)-[beta-D-glucopyranosyl-(1 --> 4)]-beta-D-galactopyranoside (1) and 26-O-beta-D-glucopyranosyl-(25S)-5alpha-furost-20(22)-en-12-one-3beta,26-diol-3-O-beta-D-galactopyranosyl-(1 --> 2)-beta-D-glucopyranosyl-(1 --> 4)-beta-D-galactopyranoside (2) on the basis of spectroscopic data as well as chemical evidence. PMID:20496191

  18. Sodium Chloride Tolerance of Terrestrial Fungi

    PubMed Central

    Tresner, H. D.; Hayes, Jean A.

    1971-01-01

    A survey was made of the NaCl tolerance of 975 species of terrestrial fungi selected from the major taxonomic classes. The penicillia and aspergilli were notably the most resistant with the majority of their species able to grow in the presence of 20% or more of NaCl. The Basidiomycetes, as a class, were decidedly the least tolerant with over half the species unable to withstand more than 2% NaCl. Uniformity of tolerance by multiple strains of various species suggests that this may provide a useful taxonomic criterion. PMID:5096381

  19. Terrestrial Gamma-Ray Flashes (TGFs)

    NASA Technical Reports Server (NTRS)

    Fishman, Gerald J.

    2010-01-01

    This slide presentation reviews the observation of Terrestrial Gamma Ray Flashes (TGFs) by Gamma-Ray Telescopes. These were: (1) BATSE /Compton Observatory, (2) Solar Spectroscopic Imager, (3) AGILE Gamma-ray Telescope, and (4) Gamma-ray Burst Monitor (GBM) on the Fermi Gamma-ray Space Telescope. It contains charts which display the counts over time, a map or the TGFs observed by the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI). and a map showing the latitude and longitude of 85 of the TGFs observed by the Fermi GBM.

  20. Accelerated stress testing of terrestrial solar cells

    NASA Technical Reports Server (NTRS)

    Prince, J. L.; Lathrop, J. W.

    1979-01-01

    A program to investigate the reliability characteristics of unencapsulated low-cost terrestrial solar cells using accelerated stress testing is described. Reliability (or parametric degradation) factors appropriate to the cell technologies and use conditions were studied and a series of accelerated stress tests was synthesized. An electrical measurement procedure and a data analysis and management system was derived, and stress test fixturing and material flow procedures were set up after consideration was given to the number of cells to be stress tested and measured and the nature of the information to be obtained from the process. Selected results and conclusions are presented.

  1. Identification of Terrestrial Reflectance From Remote Sensing

    NASA Technical Reports Server (NTRS)

    Alter-Gartenberg, Rachel; Nolf, Scott R.; Stacy, Kathryn (Technical Monitor)

    2000-01-01

    Correcting for atmospheric effects is an essential part of surface-reflectance recovery from radiance measurements. Model-based atmospheric correction techniques enable an accurate identification and classification of terrestrial reflectances from multi-spectral imagery. Successful and efficient removal of atmospheric effects from remote-sensing data is a key factor in the success of Earth observation missions. This report assesses the performance, robustness and sensitivity of two atmospheric-correction and reflectance-recovery techniques as part of an end-to-end simulation of hyper-spectral acquisition, identification and classification.

  2. End-to-end network models encompassing terrestrial, wireless, and satellite components

    NASA Astrophysics Data System (ADS)

    Boyarko, Chandler L.; Britton, John S.; Flores, Phil E.; Lambert, Charles B.; Pendzick, John M.; Ryan, Christopher M.; Shankman, Gordon L.; Williams, Ramon P.

    2004-08-01

    Development of network models that reflect true end-to-end architectures such as the Transformational Communications Architecture need to encompass terrestrial, wireless and satellite component to truly represent all of the complexities in a world wide communications network. Use of best-in-class tools including OPNET, Satellite Tool Kit (STK), Popkin System Architect and their well known XML-friendly definitions, such as OPNET Modeler's Data Type Description (DTD), or socket-based data transfer modules, such as STK/Connect, enable the sharing of data between applications for more rapid development of end-to-end system architectures and a more complete system design. By sharing the results of and integrating best-in-class tools we are able to (1) promote sharing of data, (2) enhance the fidelity of our results and (3) allow network and application performance to be viewed in the context of the entire enterprise and its processes.

  3. 15. PALEOLIMNOLOGY OF EXTREME COLD TERRESTRIAL AND EXTRATERRESTRIAL ENVIRONMENTS

    E-print Network

    Priscu, John C.

    15. PALEOLIMNOLOGY OF EXTREME COLD TERRESTRIAL AND EXTRATERRESTRIAL ENVIRONMENTS 475 R. Pienitz, M understanding of life's origins on our planet and other extraterrestrial bodies. Liquid water is essential

  4. Terrestrial dominance of organic matter in north temperate lakes

    NASA Astrophysics Data System (ADS)

    Wilkinson, G.; Pace, M. L.; Cole, J. J.

    2012-12-01

    Aquatic ecosystems are hotspots of decomposition and a source of carbon dioxide to the atmosphere that is globally significant. Carbon exported from land (allochthonous) also supplements the carbon fixed by photosynthesis in aquatic ecosystems (autochthonous), contributing to the organic matter (OM) that supports aquatic consumers. Although the presence of terrestrial compounds in aquatic OM is well known, the contribution of terrestrial versus aquatic sources to the composition of OM has been quantified for only a handful of systems. Here we use stable isotopes of hydrogen and carbon to demonstrate that the terrestrial contribution to particulate organic matter (POM) is as large or larger (mean=54.6% terrestrial) than the algal contribution in 39 lakes of the northern highlands region of Wisconsin and Michigan. Further, the largest carbon pool, dissolved organic matter (DOM), is strongly dominated by allochthonous material (mean for the same set of lakes approximately 100% terrestrial). Among lakes, increases in terrestrial contribution to POM are significantly correlated with more acidic pH. Extrapolating this relationship using a survey of pH in 1692 lakes in the region reveals that, with the exception of eutrophic lakes, most of the OM in lakes is of terrestrial origin. These results are consistent with the growing evidence that terrestrial OM may support many lake food webs, and that lakes are significant conduits for returning degraded terrestrial carbon to the atmosphere.

  5. Developing Consistent Earth System Data Records for the Global Terrestrial Water Cycle: Focus on Shortwave and Longwave Radiative Fluxes

    NASA Astrophysics Data System (ADS)

    Pinker, R. T.; Ma, Y.; Nussbaumer, E. A.

    2012-04-01

    The overall goal of the MEaSUREs activity titled: "Developing Consistent Earth System Data Records for the Global Terrestrial Water Cycle" is to develop consistent, long-term Earth System Data Records (ESDRs) for the major components of the terrestrial water cycle at a climatic time scale. The shortwave (SW) and longwave (LW) radiative fluxes at the Earth's surface determine the exchange of energy between the land and the atmosphere are the focus of this presentation. During the last two decades, significant progress has been made in assessing the Earth Radiation Balance from satellite observations. Yet, satellite based estimates differ from each other and long term satellite observations at global scale are not readily available. There is a need to utilize existing records of satellite observations and to improve currently available estimates. This paper reports on improvements introduced to an existing methodology to estimate shortwave (SW) radiative fluxes within the atmospheric system, on the development of a new inference scheme for deriving LW fluxes, the implementation of the approach with the ISCCP DX observations and improved atmospheric inputs for the period of 1983-2007, evaluation against ground observations, and comparison with independent satellite methods and numerical models. The resulting ESDRs from the entire MEaSUREs Project are intended to provide a consistent basis for estimating the mean state and variability of the land surface water cycle at a spatial scale relevant to major global river basins. MEaSUREs Project "Developing Consistent Earth System Data Records for the Global Terrestrial Water Cycle" Team Members: E. F. Wood (PI)1, T. J Bohn2, J. L Bytheway3, X. Feng4, H. Gao2, P. R.Houser4 (CO-I), C. D Kummerow3 (CO-I), D. P Lettenmaier2 (CO-I), C. Li5, Y. Ma5, R. F MacCracken4, M. Pan1, R. T Pinker5 (CO-I), A. K. Sahoo1, J. Sheffield1 1. Dept of CEE, Princeton University, Princeton, NJ, USA. 2. Dept of CEE, University of Washington, Seattle, WA, USA. 3. Dept of Atmospheric Science, Fort Collins, CO, USA. 4. Dept of Geography and GeoInformation Scie., George Mason University, Fairfax, VA, USA. 5. Dept of Meteorology, University of Maryland, College Park, MD, USA.

  6. The Solar-Terrestrial data Analysis and Reference System (STARS)

    NASA Astrophysics Data System (ADS)

    Murata, K. T.; Kimura, E.; Shinohara, I.

    2005-12-01

    One of the problems for all of the Earth-scale observations is the circulation of the observation data. In the Solar-Terrestrial Physics (STP), variety types of spacecraft and ground-based observations have been done, and, as a result, large amounts of data have been stored and still being stored. These observations have been usually conducted by different organizations, thus the observation data are stored, managed and publicized independently. The present study is devoted to develop a global system, the Solar-Terrestrial data Analysis and Reference System (STARS), for easy accesses to these independently managed observation data seamlessly, without paying attention to where they are provided. For the use of such distributed databases, it is preferable to make full use of the Internet. We first constructed a meta-database of the STP observation data. This database manages the directory information of data files, including data site information and data file information. It also manages users_f affiliation and attributes since, in the STP, data access are often restricted to the mission members only for a certain period after the beginning of the mission. The number of meta-data record is now more than 2,000,000. It contains the information of the ISAS/JAXA spacecraft observation data files, the CDAWeb (GSFC/NASA) data files, magnetograms and geo-magnetic indices data files, the polar region observation data files by NIPR, STE laboratory and NICT in Japan, and other observation data files. We then constructed a network application, by which everyone is able to make use of the meta-data through the Internet. The application searches, visualizes and analyzes the observation data. The STARS application communicates with the meta-database using the XML Web Service (hereafter Web Service). The Web Service provides with so-called "loose connection", thus seems to be most adequate for the use of the STP data over the Internet. Using the STARS application, uses on the Internet are able to get data file information, download them and make plots. The XML is used not only for the Web Service, but for the exchanges of data plots, personal discoveries of special events, and knowledge of data analyses between the users through the Internet. This system will, therefore, show us a new paradigm of the STP data analyses.

  7. Terrestrial applications of the heatpipe power system

    SciTech Connect

    Houts, M.G.; Poston, D.I.

    1997-02-01

    A terrestrial reactor that uses the same design approach as the Heatpipe Power System (HPS) may have applications both on earth and on other planetary surfaces. The baseline HPS is a potential, near-term, low-cost space fission power system. The system will be composed of independent modules, and all components operate within the existing database. The HPS has relatively few system integration issues; thus, the successful development of a module is a significant step toward verifying system feasibility and performance estimates. A prototypic, refractory-metal HPS module is being fabricated, and testing is scheduled to begin in November 1996. A successful test will provide high confidence that the HPS can achieve its predicted performance. An HPS incorporating superalloys will be better suited for some terrestrial or planetary applications. Fabrication and testing of a superalloy HPS module should be less challenging than that of the refractory metal module. A superalloy HPS core capable of delivering > 100 kWt to a power conversion subsystem could be fabricated for about $500k (unfueled). Tests of the core with electric heat (used to simulate heat from fission) could demonstrate normal and off-normal operation of the core, including the effects of heatpipe failure. A power conversion system also could be coupled to the core to demonstrate full system operation.

  8. Grazers: biocatalysts of terrestrial silica cycling

    PubMed Central

    Vandevenne, Floor Ina; Barão, Ana Lúcia; Schoelynck, Jonas; Smis, Adriaan; Ryken, Nick; Van Damme, Stefan; Meire, Patrick; Struyf, Eric

    2013-01-01

    Silica is well known for its role as inducible defence mechanism countering herbivore attack, mainly through precipitation of opaline, biogenic silica (BSi) bodies (phytoliths) in plant epidermal tissues. Even though grazing strongly interacts with other element cycles, its impact on terrestrial silica cycling has never been thoroughly considered. Here, BSi content of ingested grass, hay and faeces of large herbivores was quantified by performing multiple chemical extraction procedures for BSi, allowing the assessment of chemical reactivity. Dissolution experiments with grass and faeces were carried out to measure direct availability of BSi for dissolution. Average BSi and readily soluble silica numbers were higher in faeces as compared with grass or hay, and differences between herbivores could be related to distinct digestive strategies. Reactivity and dissolvability of BSi increases after digestion, mainly due to degradation of organic matrices, resulting in higher silica turnover rates and mobilization potential from terrestrial to aquatic ecosystems in non-grazed versus grazed pasture systems (2 versus 20 kg Si ha?1 y?1). Our results suggest a crucial yet currently unexplored role of herbivores in determining silica export from land to ocean, where its availability is linked to eutrophication events and carbon sequestration through C–Si diatom interactions. PMID:24107532

  9. Fuel cells for extraterrestrial and terrestrial applications

    NASA Astrophysics Data System (ADS)

    Srinivasan, S.

    The fuel cell is a nineteenth century invention and a twentieth century technology development. Due to the high power and energy density, high efficiency, reliability, and production of pure water, hydrogen-oxygen fuel cell systems have no competition as auxiliary power sources for space vehicles. The alkaline fuel cell system is a well developed and proven technology for this application. The solid polymer electrolyte system may be its future competitor. The energy crisis of 1973 stimulated research, development and demonstration of the phosphoric acid, molten carbonate, solid oxide and solid polymer electrolyte fuel cell systems using natural gas, petroleum or coal derived hydrogen (and carbon monoxide for the high temperature systems) for terrestrial applications. The direct methanol-air fuel cell is still an electrochemist's dream. Though considerable technological advances have been made, the present price of crude oil, and the high capital costs and limited lifetime of fuel cell systems impede their terrestrial applications in the developed countries. Conversely, the potential for lower capital costs of labor intensive manufacturing processes and the relatively higher fossil fuel prices make these systems more attractive for such applications in the developing countries.

  10. Lunar apatite with terrestrial volatile abundances.

    PubMed

    Boyce, Jeremy W; Liu, Yang; Rossman, George R; Guan, Yunbin; Eiler, John M; Stolper, Edward M; Taylor, Lawrence A

    2010-07-22

    The Moon is thought to be depleted relative to the Earth in volatile elements such as H, Cl and the alkalis. Nevertheless, evidence for lunar explosive volcanism has been used to infer that some lunar magmas exsolved a CO-rich and CO(2)-rich vapour phase before or during eruption. Although there is also evidence for other volatile species on glass spherules, until recently there had been no unambiguous reports of indigenous H in lunar rocks. Here we report quantitative ion microprobe measurements of late-stage apatite from lunar basalt 14053 that document concentrations of H, Cl and S that are indistinguishable from apatites in common terrestrial igneous rocks. These volatile contents could reflect post-magmatic metamorphic volatile addition or growth from a late-stage, interstitial, sulphide-saturated melt that contained approximately 1,600 parts per million H(2)O and approximately 3,500 parts per million Cl. Both metamorphic and igneous models of apatite formation suggest a volatile inventory for at least some lunar materials that is similar to comparable terrestrial materials. One possible implication is that portions of the lunar mantle or crust are more volatile-rich than previously thought. PMID:20651686

  11. Carbon dioxide efficiency of terrestrial enhanced weathering.

    PubMed

    Moosdorf, Nils; Renforth, Phil; Hartmann, Jens

    2014-05-01

    Terrestrial enhanced weathering, the spreading of ultramafic silicate rock flour to enhance natural weathering rates, has been suggested as part of a strategy to reduce global atmospheric CO2 levels. We budget potential CO2 sequestration against associated CO2 emissions to assess the net CO2 removal of terrestrial enhanced weathering. We combine global spatial data sets of potential source rocks, transport networks, and application areas with associated CO2 emissions in optimistic and pessimistic scenarios. The results show that the choice of source rocks and material comminution technique dominate the CO2 efficiency of enhanced weathering. CO2 emissions from transport amount to on average 0.5-3% of potentially sequestered CO2. The emissions of material mining and application are negligible. After accounting for all emissions, 0.5-1.0 t CO2 can be sequestered on average per tonne of rock, translating into a unit cost from 1.6 to 9.9 GJ per tonne CO2 sequestered by enhanced weathering. However, to control or reduce atmospheric CO2 concentrations substantially with enhanced weathering would require very large amounts of rock. Before enhanced weathering could be applied on large scales, more research is needed to assess weathering rates, potential side effects, social acceptability, and mechanisms of governance. PMID:24597739

  12. Terrestrial applications of the heatpipe power system

    SciTech Connect

    Houts, Michael G.; Poston, David I. [Los Alamos National Laboratory, MS K551 Los Alamos, New Mexico 87545 (United States)

    1997-01-10

    A terrestrial reactor that uses the same design approach as the Heatpipe Power System (HPS) may have applications both on earth and on other planetary surfaces. The baseline HPS is a potential, near-term, low-cost space fission power system. The system will be composed of independent modules, and all components operate within the existing database. The HPS has relatively few system integration issues; thus, the successful development of a module is a significant step toward verifying system feasibility and performance estimates. A prototypic, refractory-metal HPS module is being fabricated, and testing is scheduled to begin in November 1996. A successful test will provide high confidence that the HPS can achieve its predicted performance. An HPS incorporating superalloys will be better suited for some terrestrial or planetary applications. Fabrication and testing of a superalloy HPS module should be less challenging than that of the refractory metal module. A superalloy HPS core capable of delivering >100 kWt to a power conversion subsystem could be fabricated for about $500k (unfueled). Tests of the core with electric heat (used to simulate heat from fission) could demonstrate normal and off-normal operation of the core, including the effects of heatpipe failure. A power conversion system also could be coupled to the core to demonstrate full system operation.

  13. Terrestrial applications of the heatpipe power system

    NASA Astrophysics Data System (ADS)

    Houts, Michael G.; Poston, David I.

    1997-01-01

    A terrestrial reactor that uses the same design approach as the Heatpipe Power System (HPS) may have applications both on earth and on other planetary surfaces. The baseline HPS is a potential, near-term, low-cost space fission power system. The system will be composed of independent modules, and all components operate within the existing database. The HPS has relatively few system integration issues; thus, the successful development of a module is a significant step toward verifying system feasibility and performance estimates. A prototypic, refractory-metal HPS module is being fabricated, and testing is scheduled to begin in November 1996. A successful test will provide high confidence that the HPS can achieve its predicted performance. An HPS incorporating superalloys will be better suited for some terrestrial or planetary applications. Fabrication and testing of a superalloy HPS module should be less challenging than that of the refractory metal module. A superalloy HPS core capable of delivering >100 kWt to a power conversion subsystem could be fabricated for about $500k (unfueled). Tests of the core with electric heat (used to simulate heat from fission) could demonstrate normal and off-normal operation of the core, including the effects of heatpipe failure. A power conversion system also could be coupled to the core to demonstrate full system operation.

  14. Terrestrial and Reactor Antineutrinos in Borexino

    NASA Astrophysics Data System (ADS)

    Chen, M. C.; Calaprice, F. P.; Rothschild, C. G.

    1998-10-01

    The Earth is an abundant source of antineutrinos coming from the decay of radioactive elements in the mantle and crust. Detecting these antineutrinos is a challenge due to their small cross section and low energies. The Borexino solar neutrino experiment will also be an excellent detector for bar?_e. With 300 tons of ultra-low-background liquid scintillator, surrounded by an efficient muon veto, the inverse-?-decay reaction: bar?e + p arrow e^+ + n (Q = 1.8 MeV), can be exploited to detect terrestrial antineutrinos from the uranium and thorium decay chains, with little background. A direct measurement of the total uranium and thorium abundance would establish important geophysical constraints on the heat generation and thermal history of the Earth. Starting with the most recent uranium and thorium distribution and abundance data, and employing a global map of crustal type and thickness, we calculated the antineutrino fluxes for several sites. We estimate a terrestrial antineutrino event rate in Borexino of 10 events per year. This small signal can be distinguished over the neutrino background from the world's nuclear power reactors by measuring the positron energy spectrum from the bar?e events. The possibility to perform a long-baseline oscillation experiment, reaching ? m^2 ? 10-6 eV^2, using the nuclear reactors in Europe will also be discussed.

  15. On the Capacity and System Design of Relay-Aided Underwater Acoustic Communications

    Microsoft Academic Search

    Rui Cao; Liuqing Yang; Fengzhong Qu

    2010-01-01

    In underwater acoustic communications (UAC), frequency-dependent signal attenuation, long propagation delay and doubly-selective fading channels render reliable communications a challenging problem, especially at long distances. To enhance reliability and to extend range, relay communications have been extensively studied in terrestrial environments. However, their application to UAC has not been thoroughly explored. In this paper, we analyze the capacity of relay-aided

  16. Potential markets for advanced satellite communications

    NASA Technical Reports Server (NTRS)

    Adamson, Steven; Roberts, David; Schubert, Leroy; Smith, Brian; Sogegian, Robert; Walters, Daniel

    1993-01-01

    This report identifies trends in the volume and type of traffic offered to the U.S. domestic communications infrastructure and extrapolates these trends through the year 2011. To describe how telecommunications service providers are adapting to the identified trends, this report assesses the status, plans, and capacity of the domestic communications infrastructure. Cable, satellite, and radio components of the infrastructure are examined separately. The report also assesses the following major applications making use of the infrastructure: (1) Broadband services, including Broadband Integrated Services Digital Network (BISDN), Switched Multimegabit Data Service (SMDS), and frame relay; (2) mobile services, including voice, location, and paging; (3) Very Small Aperture Terminals (VSAT), including mesh VSAT; and (4) Direct Broadcast Satellite (DBS) for audio and video. The report associates satellite implementation of specific applications with market segments appropriate to their features and capabilities. The volume and dollar value of these market segments are estimated. For the satellite applications able to address the needs of significant market segments, the report also examines the potential of each satellite-based application to capture business from alternative technologies.

  17. Nonverbal communication

    Microsoft Academic Search

    1969-01-01

    Certain nonlanguage behaviors, such as voice quality (paralanguage), body motion, touch, and use of personal space (proxemics), appear to play a prominent role in communication. Research efforts to specify and to understand the communicative function of these behaviors, here generically termed \\

  18. Communicating up

    ERIC Educational Resources Information Center

    Lum, Lydia

    2013-01-01

    Chief communicators at many U.S. institutions are interested in forging closer ties with governing boards. Proponents say such relationships can increase board trust and confidence in communicators before a crisis occurs, making it easier to manage the institution's reputation and limit negative publicity when one does. At some institutions, such…

  19. Introduction Multiple lineages of terrestrial vertebrates, including frogs,

    E-print Network

    Socha, Jake

    #12;3358 Introduction Multiple lineages of terrestrial vertebrates, including frogs, snakes- off for most vertebrates can broadly be described as a rapid straightening of bent limbs that produces, whereas an animal crossing a large gap between trees Among terrestrial vertebrate gliders, take

  20. Introduction Multiple lineages of terrestrial vertebrates, including frogs,

    E-print Network

    Socha, Jake

    3358 Introduction Multiple lineages of terrestrial vertebrates, including frogs, snakes, lizards vertebrates can broadly be described as a rapid straightening of bent limbs that produces an acceleratory jump crossing a large gap between trees Among terrestrial vertebrate gliders, take-off presents a unique problem

  1. Solomatov: Fluid Dynamics of Terrestrial Magma Ocean 323 1. INTRODUCTION

    E-print Network

    Solomatov, Slava

    Solomatov: Fluid Dynamics of Terrestrial Magma Ocean 323 323 1. INTRODUCTION A number of arguments to the hypothesis of a magma ocean. The magma ocean hypothesis provided a new basis for the explanation of a terrestrial magma ocean faced serious limitations imposed by the observed nearly chondritic abundances

  2. Energetic Metastable Oxygen and Nitrogen Atoms in the Terrestrial Atmosphere

    NASA Technical Reports Server (NTRS)

    Kharchenko, Vasili

    2003-01-01

    We have investigated the energy distributions of the metastable oxygen atoms in the terrestrial thermosphere. Nascent O(lD) atoms play a fundamental role in the energy balance and chemistry of the terrestrial atmosphere, because they are produced by photo-chemical reactions in the excited electronic states and carry significant translational energies.

  3. Planetary Science and the Terrestrial Planet Finder Mission

    Microsoft Academic Search

    V. S. Meadows; C. Dumas; S. Unwin; D. Crisp

    2003-01-01

    The Terrestrial Planet Finder Mission (TPF), is a cornerstone mission of the NASA Origins Program, and is currently scheduled for launch in the 2015 time frame. The principal scientific goal of the TPF mission is to detect and characterize terrestrial planets in the habitable zones of nearby stars, and to search for planetary-scale photometric and spectroscopic signs of habitability and

  4. China-US Collaborative Research on Life in Terrestrial

    E-print Network

    Ahmad, Sajjad

    Symposium: China-US Collaborative Research on Life in Terrestrial Geothermal Springs Information, Agenda, and Abstracts June 26-28, 2013, Kunming, China #12;Symposium: China-US Collaborative Research on Life in Terrestrial Geothermal Springs Kunming, China June 26-28, 2013 Information, Agenda

  5. CO2 stabilization, climate change and the terrestrial carbon sink

    E-print Network

    White, Andrew

    . Keywords: carbon, climate change, CO2, ecosystem, sink, tropical forest Received 20 September 1999; revised to determine impacts on ecosystems and the terrestrial carbon balance. However, they will never predictCO2 stabilization, climate change and the terrestrial carbon sink A N D R E W W H I T E , * M E L V

  6. Twentieth-Century Droughts and Their Impacts on Terrestrial Carbon

    E-print Network

    Xiao, Jingfeng

    feedback to the global climate system. KEYWORDS: Drought; Carbon cycling; Modeling 1. IntroductionTwentieth-Century Droughts and Their Impacts on Terrestrial Carbon Cycling in China Jingfeng Xiao droughts had significant effects on terrestrial carbon cycling in China, although future studies should

  7. SYMPOSIUM-IN-PRINT: ULTRAVIOLET RADIATION AND TERRESTRIAL ECOSYSTEMS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This article provides an introduction to a Symposium-in-Print on “Ultraviolet Radiation and Terrestrial Ecosystems”and summarizes the findings of ten papers that were presented at an invited “Symposium on UV Effects on Terrestrial Ecosystems” held at the annual meeting of the American Society for Ph...

  8. Terrestrial Models and Global Change: Challenges for the Future

    NASA Technical Reports Server (NTRS)

    Hurtt, George C.; Moorcroft, Paul R.; Pacala, Stephen W.; Levin, Simon A.

    1998-01-01

    A wide variety of models have illustrated the potential importance of terrestrial biological feedbacks on climate and climate change, yet our ability to make precise predictions is severely limited, due to a high degree of uncertainty. In this paper, after briefly reviewing current models, we present challenges for new terrestrial models and introduce a simple mechanistic approach that may complement existing approaches.

  9. COLD CLIMATE OIL SPILLS: A TERRESTRIAL AND FRESHWATER RESEARCH REVIEW

    EPA Science Inventory

    The first part of this study reviews world-wide research on cold climate oil spills on land to identify some of the terrestrial environmental factors in cold regions affected by oil spills and some of the techniques for measuring impacts and terrestrial systems, primarily soils. ...

  10. Microalgal and terrestrial transport biofuels to displace fossil fuels

    Microsoft Academic Search

    Lucas Reijnders

    2009-01-01

    Terrestrial transport biofuels differ in their ability to replace fossil fuels. When both the conversion of solar energy into biomass and the life cycle inputs of fossil fuels are considered, ethanol from sugarcane and biodiesel from palm oil do relatively well, if compared with ethanol from corn, sugar beet or wheat and biodiesel from rapeseed. When terrestrial biofuels are to

  11. Solar terrestrial radiation data from the Sleepers River Research Watershed

    NASA Astrophysics Data System (ADS)

    Hardy, Janet P.

    1994-08-01

    A long-term (24-year) database of solar and terrestrial radiation, as monitored in northern Vermont, has been compiled. This extensive database is a result of cooperative efforts among many different government agencies. This report summarizes the present status of the solar and terrestrial radiation database, the instrumentation and calibration, and methods of data measurement, acquisition and analysis.

  12. DISS. ETH NO. 17036 Calibration of a Terrestrial Laser Scanner

    E-print Network

    Giger, Christine

    , and the influencing parameters. Laser scanners are a black box instrument that produces a huge number of 3D pointsDISS. ETH NO. 17036 Calibration of a Terrestrial Laser Scanner for Engineering Geodesy. Recent developments have improved several aspects of terrestrial laser scanners, e.g. the data

  13. DOES TERRESTRIAL CARBON SUBSIDIZE PRODUCTION OF ESTUARINE FISH LARVAE?

    EPA Science Inventory

    The research presented demonstrates the important role that terrestrial ecosystems can play in coastal food webs. We show that terrestrial carbon subsidizes the tidal freshwater and oligohaline portions of an estuarine food web, but that this exogenous carbon source is not impor...

  14. Progress in the development of cadmium sulphide terrestrial solar batteries

    Microsoft Academic Search

    R. J. Mytton

    1974-01-01

    Recent progress in the development of a robust economical CdS solar panel for terrestrial use is described. Following a discussion of the economic reasons behind the proposed design (one which is intended to bridge the gap between individual space cells and large volume production for terrestrial power), the construction of the panel is described in detail. Particular features of the

  15. Plant regeneration using immature zygotic embryos of Tribulus terrestris

    Microsoft Academic Search

    C. Don Palmer; W. A. Keller

    2011-01-01

    The genus Tribulus is the source of a number of steroidal saponins and other bioactive compounds which are of medicinal and pharmaceutical importance\\u000a and plant regeneration of Tribulus terrestris has been reported. The objective of this study was to evaluate the potential of immature zygotic embryos of Tribulus terrestris as an explant for plant regeneration. Embryos were cultured on MS

  16. Response of Terrestrial Arthropod Assemblages to Coastal Dune Restoration

    Microsoft Academic Search

    John W. Doudna; Edward F. Connor

    2012-01-01

    To restore historical dune vegetation, substantial effort has been made to remove the invasive plant species, European beach grass (Ammophila arenaria), from coastal dunes of California, USA. However, little effort has been made to examine the response of terrestrial arthropod assemblages to coastal dune restoration. We sampled terrestrial arthropods at 6 dune restoration sites to determine the response of the

  17. Molecular evidence for a terrestrial origin of snakes

    E-print Network

    Hedges, Blair

    Molecular evidence for a terrestrial origin of snakes Nicolas Vidal and S. Blair Hedges* NASA.12.03; Published online 30.01.04 Biologists have debated the origin of snakes since the nineteenth century. One hypothesis suggests that snakes are most closely related to terrestrial lizards, and reduced their limbs

  18. Management opportunities for enhancing terrestrial CO2 sinks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To address climate change and the implications of a global mean temperature increase of more than two degrees Celsius over current levels will require terrestrial carbon (C) management along with reductions in fossil fuel emissions. To achieve all or part of the global terrestrial C sequestration p...

  19. Are there real differences among aquatic and terrestrial food webs?

    Microsoft Academic Search

    Jonathan M Chase

    2000-01-01

    Recently, aquatic and terrestrial ecologists have put forward several hypotheses regarding similarities and differences in food-web structure and function among these ecosystem types. Although many of these hypotheses explore why strong top-down effects and trophic cascades might be less common in terrestrial than in aquatic ecosystems, there is little theoretical or empirical evidence available to support or refute these hypotheses.

  20. Critical remarks on the use of terrestrial moss (Hylocomium splendens and Pleurozium schreberi) for monitoring

    E-print Network

    Filzmoser, Peter

    Critical remarks on the use of terrestrial moss (Hylocomium splendens and Pleurozium schreberi Duplicate samples of the two terrestrial moss species Hylocomium splendens and Pleurozium schreberi, which metals 1. Introduction Terrestrial moss (especially Hylocomium splendens and Pleurozium schreberi) has

  1. Similarity laws of lunar and terrestrial volcanic flows

    NASA Technical Reports Server (NTRS)

    Pai, S. I.; Hsu, Y.; Okeefe, J. A.

    1977-01-01

    A mathematical model of a one dimensional, steady duct flow of a mixture of a gas and small solid particles (rock) was analyzed and applied to the lunar and the terrestrial volcanic flows under geometrically and dynamically similar conditions. Numerical results for the equilibrium two phase flows of lunar and terrestrial volcanoes under similar conditions are presented. The study indicates that: (1) the lunar crater is much larger than the corresponding terrestrial crater; (2) the exit velocity from the lunar volcanic flow may be higher than the lunar escape velocity but the exit velocity of terrestrial volcanic flow is much less than that of the lunar case; and (3) the thermal effects on the lunar volcanic flow are much larger than those of the terrestrial case.

  2. EHF (28/19 GHz) personal communications satellite terminal development

    NASA Technical Reports Server (NTRS)

    Pike, Corey

    1991-01-01

    The concept of communicating on a personal basis using a small terminal has been investigated globally from many different applications and technology perspectives. Applications range from terrestrial handheld communicators for paging, cellular, zone voice/data networks, etc., to satellite terminals of pocket dimensions for voice/low speed data or similar terminals using larger antennas for VSAT, news gathering (30 cm), and video (1.2 m). A brief status of some developments in the satellite personal communications at CRC will be presented.

  3. Solar terrestrial coupling through space plasma processes

    SciTech Connect

    Birn, J. [and others

    2000-12-01

    This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project investigates plasma processes that govern the interaction between the solar wind, charged particles ejected from the sun, and the earth's magnetosphere, the region above the ionosphere governed by the terrestrial magnetic field. Primary regions of interest are the regions where different plasma populations interact with each other. These are regions of particularly dynamic plasma behavior, associated with magnetic flux and energy transfer and dynamic energy release. The investigations concerned charged particle transport and energization, and microscopic and macroscopic instabilities in the magnetosphere and adjacent regions. The approaches combined space data analysis with theory and computer simulations.

  4. Photovoltaic design optimization for terrestrial applications

    NASA Technical Reports Server (NTRS)

    Ross, R. G., Jr.

    1978-01-01

    As part of the Jet Propulsion Laboratory's Low-Cost Solar Array Project, a comprehensive program of module cost-optimization has been carried out. The objective of these studies has been to define means of reducing the cost and improving the utility and reliability of photovoltaic modules for the broad spectrum of terrestrial applications. This paper describes one of the methods being used for module optimization, including the derivation of specific equations which allow the optimization of various module design features. The method is based on minimizing the life-cycle cost of energy for the complete system. Comparison of the life-cycle energy cost with the marginal cost of energy each year allows the logical plant lifetime to be determined. The equations derived allow the explicit inclusion of design parameters such as tracking, site variability, and module degradation with time. An example problem involving the selection of an optimum module glass substrate is presented.

  5. Terrestrial Laser Scanning for Vegetation Sampling

    PubMed Central

    Richardson, Jeffrey J; Moskal, L. Monika; Bakker, Jonathan D.

    2014-01-01

    We developed new vegetation indices utilizing terrestrial laser scanning (TLS) to quantify the three-dimensional spatial configuration of plant communities. These indices leverage the novelty of TLS data and rely on the spatially biased arrangement of a TLS point cloud. We calculated these indices from TLS data acquired within an existing long term manipulation of forest structure in Central Oregon, USA, and used these data to test for differences in vegetation structure. Results provided quantitative evidence of a significant difference in vegetation density due to thinning and burning, and a marginally significant difference in vegetation patchiness due to grazing. A comparison to traditional field sampling highlighted the novelty of the TLS based method. By creating a linkage between traditional field sampling and landscape ecology, these indices enable field investigations of fine-scale spatial patterns. Applications include experimental assessment, long-term monitoring, and habitat characterization. PMID:25353981

  6. Terrestrial kilometric radiation - The cyclotron theory

    NASA Technical Reports Server (NTRS)

    Melrose, D. B.; Hewitt, R. G.; Ronnmark, K. G.

    1982-01-01

    It is shown that electrons in inverted V events can cause direct, amplified cyclotron emission (x-mode radiation) above the cutoff frequency, and the growth rate of the waves is calculated by using inverted V electron event observations as the inputs of a numerical code. Calculation results exhibiting wave growth are adduced as evidence for the cyclotron interpretation of terrestrial kilometric radiation (TKR). It is speculated that the specific electron distribution features which generate TKR should disappear in much less than a second, and should therefore not be observable in particle data averaged over more than one second. The basic electron distribution feature that gives rise to TKR is a one-sided loss cone anisotropy in which upward moving electrons with small pitch angles are missing. The features causing large growth rates may be due to the effects of the parallel electric field.

  7. Accelerated stress testing of terrestrial solar cells

    NASA Technical Reports Server (NTRS)

    Lathrop, J. W.; Hawkins, D. C.; Prince, J. L.; Walker, H. A.

    1982-01-01

    The development of an accelerated test schedule for terrestrial solar cells is described. This schedule, based on anticipated failure modes deduced from a consideration of IC failure mechanisms, involves bias-temperature testing, humidity testing (including both 85-85 and pressure cooker stress), and thermal-cycle thermal-shock testing. Results are described for 12 different unencapsulated cell types. Both gradual electrical degradation and sudden catastrophic mechanical change were observed. These effects can be used to discriminate between cell types and technologies relative to their reliability attributes. Consideration is given to identifying laboratory failure modes which might lead to severe degradation in the field through second quadrant operation. Test results indicate that the ability of most cell types to withstand accelerated stress testing depends more on the manufacturer's design, processing, and worksmanship than on the particular metallization system. Preliminary tests comparing accelerated test results on encapsulated and unencapsulated cells are described.

  8. Terrestrial nitrogen cycles: Some unanswered questions

    NASA Technical Reports Server (NTRS)

    Vitousek, P.

    1984-01-01

    Nitrogen is generally considered to be the element which most often limits the growth of plants in both natural and agricultural ecosystems. It regulates plant growth because photosynthetic rates are strongly dependent on the concentration of nitrogen in leaves, and because relatively large mounts of protein are required for cell division and growth. Yet nitrogen is abundant in the biosphere - the well-mixed pool in the atmosphere is considered inexhaustible compared to biotic demand, and the amount of already fixed organic nitrogen in soils far exceeds annual plant uptake in terrestrial ecosystems. In regions where natural vegetation is not nitrogen limited, continuous cultivation induces nitrogen deficiency. Nitrogen loss from cultivated lands is more rapid than that of other elements, and nitrogen fertilization is generally required to maintain crop yield under any continuous system. The pervasiveness of nitrogen deficiency in many natural and most managed sites is discussed.

  9. The origin of modern terrestrial life

    PubMed Central

    Forterre, Patrick; Gribaldo, Simonetta

    2007-01-01

    The study of the origin of life covers many areas of expertise and requires the input of various scientific communities. In recent years, this research field has often been viewed as part of a broader agenda under the name of “exobiology” or “astrobiology.” In this review, we have somewhat narrowed this agenda, focusing on the origin of modern terrestrial life. The adjective “modern” here means that we did not speculate on different forms of life that could have possibly appeared on our planet, but instead focus on the existing forms (cells and viruses). We try to briefly present the state of the art about alternative hypotheses discussing not only the origin of life per se, but also how life evolved to produce the modern biosphere through a succession of steps that we would like to characterize as much as possible. PMID:19404443

  10. The polarization of escaping terrestrial continuum radiation

    NASA Technical Reports Server (NTRS)

    Gurnett, D. A.; Calvert, W.; Huff, R. L.; Jones, D.; Sugiura, M.

    1988-01-01

    The polarization of an escaping terrestrial continuum radiation event that occurred on March 2, 1982, was determined using plasma wave measurements from the DE-1 spacecraft. The source of the radiation was determined to be located near the magnetic equator on the nightside of the earth at a radial distance of about 2.8-3.5 earth radii. Two meridional beams were detected, one directed north at an angle of about 20-30 deg with respect to the magnetic equator, and the other directed south at a comparable angle. Polarization measurements indicated that the radiation is right-hand polarized with respect to an outward directed E plane normal in the Northern Hemisphere and left-hand polarized in the Southern Hemisphere.

  11. New steroidal glycosides from Tribulus terrestris L.

    PubMed

    Chen, Gang; Liu, Tao; Lu, Xuan; Wang, Hai-Feng; Hua, Hui-Ming; Pei, Yue-Hu

    2012-01-01

    Two new steroidal glycosides were isolated from Tribulus terrestris L. Their structures were elucidated as 26-O-?-D-glucopyranosyl-5?-furostan-12-one-20(22)-ene-3?,23,26-triol-3-O-?-D-xylopyranosyl-(1 ? 2)-[?-D-xylopyranosyl-(1 ? 3)]-?-D-glucopyranosyl-(1 ? 4)-[?-L-rhamnopyranosyl-(1 ? 2)]-?-D-galactopyranoside (1) and 26-O-?-D-glucopyranosyl-5?-furostan-20(22)-ene-3?,23,26-triol-3-O-?-D-xylopyranosyl-(1 ? 2)-[?-D-xylopyranosyl-(1 ? 3)]-?-D-glucopyranosyl-(1 ? 4)-[?-L-rhamnopyranosyl-(1 ? 2)]-?-D-galactopyranoside (2) by spectroscopic methods including 1D and 2D NMR experiments. PMID:22694659

  12. Intermittent Astrophysical Radiation Sources and Terrestrial Life

    NASA Astrophysics Data System (ADS)

    Melott, Adrian

    2013-04-01

    Terrestrial life is exposed to a variety of radiation sources. Astrophysical observations suggest that strong excursions in cosmic ray flux and spectral hardness are expected. Gamma-ray bursts and supernovae are expected to irradiate the atmosphere with keV to GeV photons at irregular intervals. Supernovae will produce large cosmic ray excursions, with time development varying with distance from the event. Large fluxes of keV to MeV protons from the Sun pose a strong threat to electromagnetic technology. The terrestrial record shows cosmogenic isotope excursions which are consistent with major solar proton events, and there are observations of G-stars suggesting that the rate of such events may be much higher than previously assumed. In addition there are unknown and unexplained astronomical transients which may indicate new classes of events. The Sun, supernovae, and gamma-ray bursts are all capable of producing lethal fluences, and some are expected on intervals of 10^8 years or so. The history of life on Earth is filled with mass extinctions at a variety of levels of intensity. Most are not understood. Astrophysical radiation may play a role, particularly from large increases in muon irradiation on the ground, and changes in atmospheric chemistry which deplete ozone, admitting increased solar UVB. UVB is strongly absorbed by DNA and proteins, and breaks the chemical bonds---it is a known carcinogen. High muon fluxes will also be damaging to such molecules, but experiments are needed to pin down the rate. Solar proton events which are not directly dangerous for the biota may nevertheless pose a major threat to modern electromagnetic technology through direct impact on satellites and magnetic induction of large currents in power grids, disabling transformers. We will look at the kind of events that are expected on timescales from human to geological, and their likely consequences.

  13. Grazing livestock are exposed to terrestrial cyanobacteria.

    PubMed

    McGorum, Bruce C; Pirie, R Scott; Glendinning, Laura; McLachlan, Gerry; Metcalf, James S; Banack, Sandra A; Cox, Paul A; Codd, Geoffrey A

    2015-01-01

    While toxins from aquatic cyanobacteria are a well-recognised cause of disease in birds and animals, exposure of grazing livestock to terrestrial cyanobacteria has not been described. This study identified terrestrial cyanobacteria, predominantly Phormidium spp., in the biofilm of plants from most livestock fields investigated. Lower numbers of other cyanobacteria, microalgae and fungi were present on many plants. Cyanobacterial 16S rDNA, predominantly from Phormidium spp., was detected in all samples tested, including 6 plant washings, 1 soil sample and ileal contents from 2 grazing horses. Further work was performed to test the hypothesis that ingestion of cyanotoxins contributes to the pathogenesis of some currently unexplained diseases of grazing horses, including equine grass sickness (EGS), equine motor neuron disease (EMND) and hepatopathy. Phormidium population density was significantly higher on EGS fields than on control fields. The cyanobacterial neurotoxic amino acid 2,4-diaminobutyric acid (DAB) was detected in plant washings from EGS fields, but worst case scenario estimations suggested the dose would be insufficient to cause disease. Neither DAB nor the cyanobacterial neurotoxins ?-N-methylamino-L-alanine and N-(2-aminoethyl) glycine were detected in neural tissue from 6 EGS horses, 2 EMND horses and 7 control horses. Phormidium was present in low numbers on plants where horses had unexplained hepatopathy. This study did not yield evidence linking known cyanotoxins with disease in grazing horses. However, further study is warranted to identify and quantify toxins produced by cyanobacteria on livestock fields, and determine whether, under appropriate conditions, known or unknown cyanotoxins contribute to currently unexplained diseases in grazing livestock. PMID:25828258

  14. Future hotspots of terrestrial mammal loss

    PubMed Central

    Visconti, Piero; Pressey, Robert L.; Giorgini, Daniele; Maiorano, Luigi; Bakkenes, Michel; Boitani, Luigi; Alkemade, Rob; Falcucci, Alessandra; Chiozza, Federica; Rondinini, Carlo

    2011-01-01

    Current levels of endangerment and historical trends of species and habitats are the main criteria used to direct conservation efforts globally. Estimates of future declines, which might indicate different priorities than past declines, have been limited by the lack of appropriate data and models. Given that much of conservation is about anticipating and responding to future threats, our inability to look forward at a global scale has been a major constraint on effective action. Here, we assess the geography and extent of projected future changes in suitable habitat for terrestrial mammals within their present ranges. We used a global earth-system model, IMAGE, coupled with fine-scale habitat suitability models and parametrized according to four global scenarios of human development. We identified the most affected countries by 2050 for each scenario, assuming that no additional conservation actions other than those described in the scenarios take place. We found that, with some exceptions, most of the countries with the largest predicted losses of suitable habitat for mammals are in Africa and the Americas. African and North American countries were also predicted to host the most species with large proportional global declines. Most of the countries we identified as future hotspots of terrestrial mammal loss have little or no overlap with the present global conservation priorities, thus confirming the need for forward-looking analyses in conservation priority setting. The expected growth in human populations and consumption in hotspots of future mammal loss mean that local conservation actions such as protected areas might not be sufficient to mitigate losses. Other policies, directed towards the root causes of biodiversity loss, are required, both in Africa and other parts of the world. PMID:21844048

  15. Design for minimum energy in interstellar communication

    NASA Astrophysics Data System (ADS)

    Messerschmitt, David G.

    2015-02-01

    Microwave digital communication at interstellar distances is the foundation of extraterrestrial civilization (SETI and METI) communication of information-bearing signals. Large distances demand large transmitted power and/or large antennas, while the propagation is transparent over a wide bandwidth. Recognizing a fundamental tradeoff, reduced energy delivered to the receiver at the expense of wide bandwidth (the opposite of terrestrial objectives) is advantageous. Wide bandwidth also results in simpler design and implementation, allowing circumvention of dispersion and scattering arising in the interstellar medium and motion effects and obviating any related processing. The minimum energy delivered to the receiver per bit of information is determined by cosmic microwave background alone. By mapping a single bit onto a carrier burst, the Morse code invented for the telegraph in 1836 comes closer to this minimum energy than approaches used in modern terrestrial radio. Rather than the terrestrial approach of adding phases and amplitudes increases information capacity while minimizing bandwidth, adding multiple time-frequency locations for carrier bursts increases capacity while minimizing energy per information bit. The resulting location code is simple and yet can approach the minimum energy as bandwidth is expanded. It is consistent with easy discovery, since carrier bursts are energetic and straightforward modifications to post-detection pattern recognition can identify burst patterns. Time and frequency coherence constraints leading to simple signal discovery are addressed, and observations of the interstellar medium by transmitter and receiver constrain the burst parameters and limit the search scope.

  16. Science communication as political communication.

    PubMed

    Scheufele, Dietram A

    2014-09-16

    Scientific debates in modern societies often blur the lines between the science that is being debated and the political, moral, and legal implications that come with its societal applications. This manuscript traces the origins of this phenomenon to professional norms within the scientific discipline and to the nature and complexities of modern science and offers an expanded model of science communication that takes into account the political contexts in which science communication takes place. In a second step, it explores what we know from empirical work in political communication, public opinion research, and communication research about the dynamics that determine how issues are debated and attitudes are formed in political environments. Finally, it discusses how and why it will be increasingly important for science communicators to draw from these different literatures to ensure that the voice of the scientific community is heard in the broader societal debates surrounding science. PMID:25225389

  17. Information & Communications

    E-print Network

    Popeea, Corneliu - Chair for Foundations of Software Reliability and Theoretical Computer Science

    Model & % " " ( & # % & ) # # * % ' ) # # * & Metabolism Drug Screening #12;© Siemens AG, CT IC 4, 2003 IC 4, 2003 Information & Communications Neural Computation EmotionLong Term Memory Working Memory Attentional Filtering Object/Spatial Memory Rule Memory Attention Object-Based Attention, Spatial Attention

  18. Acoustic Communication

    NSDL National Science Digital Library

    0000-00-00

    Concise lecture on sound production in insects. Stridulation, forced air through spiracles, wing vibration, and tapping are all discussed with examples. Advantages and disadvantages of sound production are also discussed. The page also links to chemical, and visual communication pages.

  19. Military communications

    Microsoft Academic Search

    Torleiv Maseng; Randall Landry; Kenneth Young

    2009-01-01

    This feature topic on military communications includes five articles that deal primarily with wireless tactical networks, covering topics ranging from security to software defined radio design and mobile ad hoc networks (MANETs) for covert battlefield operations.

  20. THE COMPOSITIONAL DIVERSITY OF EXTRASOLAR TERRESTRIAL PLANETS. II. MIGRATION SIMULATIONS

    SciTech Connect

    Carter-Bond, Jade C. [School of Physics, University of New South Wales, Kensington, NSW 2052 (Australia); O'Brien, David P. [Planetary Science Institute, 1700 East Fort Lowell, Tucson, AZ 85719 (United States); Raymond, Sean N., E-mail: j.bond@unsw.edu.au [Observatoire Aquitain des Sciences de l'Univers, Universite de Bordeaux, 2 rue de l'Observatoire, BP 89, F-33271 Floirac Cedex (France)

    2012-11-20

    Prior work has found that a variety of terrestrial planetary compositions are expected to occur within known extrasolar planetary systems. However, such studies ignored the effects of giant planet migration, which is thought to be very common in extrasolar systems. Here we present calculations of the compositions of terrestrial planets that formed in dynamical simulations incorporating varying degrees of giant planet migration. We used chemical equilibrium models of the solid material present in the disks of five known planetary host stars: the Sun, GJ 777, HD4203, HD19994, and HD213240. Giant planet migration has a strong effect on the compositions of simulated terrestrial planets as the migration results in large-scale mixing between terrestrial planet building blocks that condensed at a range of temperatures. This mixing acts to (1) increase the typical abundance of Mg-rich silicates in the terrestrial planets' feeding zones and thus increase the frequency of planets with Earth-like compositions compared with simulations with static giant planet orbits, and (2) drastically increase the efficiency of the delivery of hydrous phases (water and serpentine) to terrestrial planets and thus produce waterworlds and/or wet Earths. Our results demonstrate that although a wide variety of terrestrial planet compositions can still be produced, planets with Earth-like compositions should be common within extrasolar planetary systems.

  1. Terrestrial Ages of Antarctic Meteorites: Up Date 1999

    NASA Technical Reports Server (NTRS)

    Nishiizumi, K.; Caffee, M. W.; Welten, K. C.

    2000-01-01

    We are continuing our ongoing study of cosmogenic nuclides in Antarctic meteorites. In addition to the studies of exposure histories of meteorites, we study terrestrial ages and pairing of Antarctic meteorites and desert meteorites. Terrestrial ages of Antarctic meteorites provide information on meteorite accumulation mechanisms, mean weathering lifetimes, and influx rates. The determination of Cl-36 (half-life=3.01 x 10(exp 5) y) terrestrial ages is one of our long-term on-going projects, however, in many instances neither Cl-36 or C-14 (5,730 y) yields an accurate terrestrial age. Using Ca-41 (1.04 x 10(exp 5) y) for terrestrial age determinations solves this problem by filling the gap in half-life between C-14 and Cl-36 ages. We are now applying the new Ca-41 - Cl-36 terrestrial age method as well as the Cl-36 - Be-10 method to Antarctic meteorites. Our measurements and C-14 terrestrial age determinations by the University of Arizona group are always complementary.

  2. Application of terrestrial 'structure-from-motion' photogrammetry on a medium-size Arctic valley glacier: potential, accuracy and limitations

    NASA Astrophysics Data System (ADS)

    Hynek, Bernhard; Binder, Daniel; Boffi, Geo; Schöner, Wolfgang; Verhoeven, Geert

    2014-05-01

    Terrestrial photogrammetry was the standard method for mapping high mountain terrain in the early days of mountain cartography, until it was replaced by aerial photogrammetry and airborne laser scanning. Modern low-price digital single-lens reflex (DSLR) cameras and highly automatic and cheap digital computer vision software with automatic image matching and multiview-stereo routines suggest the rebirth of terrestrial photogrammetry, especially in remote regions, where airborne surveying methods are expensive due to high flight costs. Terrestrial photogrammetry and modern automated image matching is widely used in geodesy, however, its application in glaciology is still rare, especially for surveying ice bodies at the scale of some km², which is typical for valley glaciers. In August 2013 a terrestrial photogrammetric survey was carried out on Freya Glacier, a 6km² valley glacier next to Zackenberg Research Station in NE-Greenland, where a detailed glacier mass balance monitoring was initiated during the last IPY. Photos with a consumer grade digital camera (Nikon D7100) were taken from the ridges surrounding the glacier. To create a digital elevation model, the photos were processed with the software photoscan. A set of ~100 dGPS surveyed ground control points on the glacier surface was used to georeference and validate the final DEM. Aim of this study was to produce a high resolution and high accuracy DEM of the actual surface topography of the Freya glacier catchment with a novel approach and to explore the potential of modern low-cost terrestrial photogrammetry combined with state-of-the-art automated image matching and multiview-stereo routines for glacier monitoring and to communicate this powerful and cheap method within the environmental research and glacier monitoring community.

  3. Police Communications

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Oklahoma City Police Department developed a computerized communications system, based on Johnson Space Center's (JSC's) 1960-mission control knowledge. JSC furnished information on lighting and other fatigue reducing measures, and provided specifications for equipment and design layouts. JSC also advised OCPD how to avoid communications bottlenecks associated with simultaneous handling of telephone, radio and inner-office transmissions. Oklahoma City saved money in reduced design and engineering costs by utilizing the already developed NASA technology.

  4. Engineering Communication

    NSDL National Science Digital Library

    Heitkamp, Greg

    This engineering communication overview, created by Greg Heitkamp and published by the Engineering Technology Pathways project, gives students background in the "ability to express what is going on to different parts of a project" in engineering so that the project goes smoothly. A number of different approaches are discussed, including concurrent engineering and integrated product development (IPD), along with the benefits and disadvantages of each. This is a helpful introduction for engineering students to become acquainted with the communication fundamentals in the field.

  5. Terrestrial nitrogen–carbon cycle interactions at the global scale

    PubMed Central

    Zaehle, S.

    2013-01-01

    Interactions between the terrestrial nitrogen (N) and carbon (C) cycles shape the response of ecosystems to global change. However, the global distribution of nitrogen availability and its importance in global biogeochemistry and biogeochemical interactions with the climate system remain uncertain. Based on projections of a terrestrial biosphere model scaling ecological understanding of nitrogen–carbon cycle interactions to global scales, anthropogenic nitrogen additions since 1860 are estimated to have enriched the terrestrial biosphere by 1.3 Pg N, supporting the sequestration of 11.2 Pg C. Over the same time period, CO2 fertilization has increased terrestrial carbon storage by 134.0 Pg C, increasing the terrestrial nitrogen stock by 1.2 Pg N. In 2001–2010, terrestrial ecosystems sequestered an estimated total of 27 Tg N yr?1 (1.9 Pg C yr?1), of which 10 Tg N yr?1 (0.2 Pg C yr?1) are due to anthropogenic nitrogen deposition. Nitrogen availability already limits terrestrial carbon sequestration in the boreal and temperate zone, and will constrain future carbon sequestration in response to CO2 fertilization (regionally by up to 70% compared with an estimate without considering nitrogen–carbon interactions). This reduced terrestrial carbon uptake will probably dominate the role of the terrestrial nitrogen cycle in the climate system, as it accelerates the accumulation of anthropogenic CO2 in the atmosphere. However, increases of N2O emissions owing to anthropogenic nitrogen and climate change (at a rate of approx. 0.5 Tg N yr?1 per 1°C degree climate warming) will add an important long-term climate forcing. PMID:23713123

  6. Briefcase Communicator

    NASA Technical Reports Server (NTRS)

    1979-01-01

    In the photo at bottom right, a U.S. Park Police officer is demonstrating a battery-powered communications system, sufficiently compact to be packed in a briefcase-size container, which can send and receive signals over great distances by means of satellite relay. Key to the system's efficacy is the high-powered transmitting and receiving equipment aboard such NASA satellites as the Applications Technology Satellite6 (ATS-6) and the joint U.S.-Canadian Communications Technology Satellite (CTS); this enables the briefcase communicator to pick up satellite-relayed signals by means of the small hook-on antenna shown instead of the more elaborate-ground equipment customarily needed. Developed by NASA's Goddard Space Flight Center, the communicator is intended for use in emergency situations. It has utility, for example, in disasters, such as floods and hurricanes, where power failure disrupts conventional communications; for on-the-spot transmissions from major accident sites; or in remote areas where no other means of communication exists

  7. Use of communications. [satellite communication

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Progress in the field of satellite communications is reviewed, and useful services which may be provided by future satellite communications systems are considered. Recommendations are made with regard to mobile communications for use on land and at sea, position determination, mineral and energy exploration, the possibility of using electronic means to assist in main delivery, education and health-care experiments, and the use of satellite telecommunications to enhance the quality of life in rural areas by making available a full range of educational and entertainment programs. The needs of the amateur radio community are also considered.

  8. Integration and assimilation of remote and terrestrial data for monitoring rock glaciers deformations: the innovative experiences from the SloMove project

    NASA Astrophysics Data System (ADS)

    Chinellato, Giulia; Cuozzo, Giovanni; Callegari, Mattia; Thiebes, Benni; Kenner, Robert; Petitta, Marcello

    2015-04-01

    We propose an innovative data integration methodology for monitoring landslides and slow moving processes such as rock glaciers. Within the Interreg project Slomove, we assimilated different sources of displacement data, such as GPS, terrestrial laserscans and DInSAR into a new field which integrates the information from all the measurement techniques. The new displacements field is obtained using the well-know approach of 3DVAR used in atmospheric science to assimilated data in dynamical models. This approach produces the best observing field combining the information from different sources and minimizing the errors and the uncertainties associated to each native field (in our case GPS, laserscans and InSAR data). The methodology was developed during the Interreg-funded research project SloMove, (www.SloMove.eu) which dealt with the monitoring of slow moving processes in high alpine environments. During the project duration (2012 - 2014), rock glacier movements and deformations in Switzerland and Italy were regularly monitored using satellite-based DInSAR, terrestrial laserscanning and differential GNSS. A major challenge of the project was to integrate terrestrial and remotely-sensed data sources and to investigate the benefits and limitations of the methods and their application in an alpine setting. GPS campaigns were carried out one time in 2012 and three times a year in 2013 and 2014, terrestrial laserscans once a year. Artificial reflectors were installed on the test sites with the aim of improving the application of satellite-based DInSAR analyses. Radar data from the Cosmo SkyMed satellite was processed using the SBAS algorithm. The study was carried out at two test-sites located in Grisons (Switzerland) and South Tyrol (Italy). The Swiss site is located above Pontresina in the Upper Engadin valley. The monitoring area includes three individual active rock glaciers in a West oriented mountain cirque called Foura da l'amd Ursina. The rock glaciers are henceforth referred to as Ursina I to III and are located between 2700 and 2900 m asl. The steep surrounding ridges and rock walls are over 3000 m high and are subject to intermittent rockfall activity. The results of the assimilation analysis show a cumulative 3D displacement up to 50 cm in 2 years, and an average velocity of deformation up to 2 cm/y in the Swiss area. In particular, the collected data provide information about the trend of deformation of the three rock glaciers, identifying the faster zone in the front of Ursina I. The presentation will focus on the data integration and the lessons learned in the SloMove project. Challenges of data integration, with a focus on the problems arising in rough alpine terrain will be highlighted and best-practice experiences will be shared with the scientific community.

  9. Probing terrestrial mantle evolution using Ru isotopes

    NASA Astrophysics Data System (ADS)

    Bermingham, K. R.; Walker, R. J.; Puchtel, I. S.; O'Driscoll, B.

    2013-12-01

    A diversity of materials was likely added to Earth during the late stages of its accretion; however, the specific elemental and isotopic compositions of these contributors are poorly constrained. The efficiency with which these late accreted materials were mixed into the mantle also remains an open question. The highly siderophile element ruthenium (Ru) provides a potentially useful isotopic genetic tracer for late accretionary additions to Earth. Well resolved deficiencies in 100Ru have been reported on the scale of whole-rock samples of meteorites, and are interpreted to stem from the heterogeneous distribution of s-process carrier phases in the solar nebula [1,2]. Isotopically diverse materials are, therefore, likely contributors of late accreted materials to Earth's mantle. Recent isotopic studies have found that major accretionary events (e.g., the Moon-forming giant impact) did not completely homogenize the mantle; thus, long-term preservation of isotopically distinct reservoirs in the mantle might be expected [3]. Identification of isotopically heterogeneous domains in the mantle using Ru isotopic analyses can potentially reveal the nature of different impactors. To investigate the genetics of late accretionary additions and to evaluate the veracity of late accretionary models, we have developed a refined analytical technique for the high-precision measurement of Ru isotopic composition using negative thermal ionization mass spectrometry (N-TIMS). Replicate analyses of an Alfa Aesar Ru standard (n = 56) over the period of several months indicate a current external precision of ×8 ppm (2? SD) for 100Ru/101Ru. Data are corrected for instrumental mass fractionation using the exponential law and 99Ru/101Ru as the normalizing ratio. Data are also corrected for oxide interferences assuming a natural oxygen isotopic composition. No second order oxygen correction is required [3]. Prior to this study, the highest external precision achieved using standard N-TIMS or MC-ICP-MS techniques has typically been between ×25 and 30 ppm [1,2]. Thus, the external precision achieved in our study so far is a factor of ~4 higher than in any previous measurements. In the beginning stages of this study, a suite of chromitites from the 492 Ma old Shetland ophiolite complex has been analyzed to test the extent of mantle heterogeneity preserved in relatively young terrestrial materials. Repeat analyses of Ru fractions from these chromitites show no statistically significant deviations of 100Ru/101Ru from the terrestrial standard, thus, indicating a homogeneous mantle composition during this late stage of mantle evolution. Isotopic heterogeneity, however, may be preserved in older terrestrial materials and we have begun the search for these heterogeneities. [1] Chen et al. (2010) Geochim. Cosmochim. Acta 74, 3851-3862. [2] Fischer-Gödde et al., (2013) 44th Lunar Planet. Sci. Conf. #2456 (abstr.) [3] Touboul et al. (2012) Science 335, 1065-1069.

  10. Simulation results of aboveground woody biomass and leaf litterfall for African tropical forest with a global terrestrial model

    NASA Astrophysics Data System (ADS)

    De Weirdt, Marjolein; Maignan, Fabienne; Peylin, Philippe; Poulter, Benjamin; Moreau, Inès; Ciais, Philippe; Defourny, Pierre; Steppe, Kathy; Verbeeck, Hans

    2014-05-01

    The response of tropical forest vegetation to global climate change could be central to predictions of future levels of atmospheric carbon dioxide. Tropical forests are believed to annually process approximately six times as much carbon via photosynthesis and respiration as humans emit from fossil fuel use. Of all tropical forests worldwide, the role of African tropical forest is not very well known and both the quantity as well as the dynamics of tropical forest carbon stocks and fluxes are very poorly quantified components of the global carbon cycle. Furthermore, African tropical forest spatial carbon stocks patterns as measured in the field are not as well represented by the global biogeochemical models as they are for temperate forests. In this study, a first simulation for the African tropical forest with the process based global terrestrial ecosystem model ORCHIDEE was done. In this work, ORCHIDEE included deep soils, seasonal leaf litterfall and phosphorus availability mechanisms for tropical evergreen forests included. The ORCHIDEE model run outputs are evaluated against reported field inventories, investigating seasonal variations in leaf litterfall and spatial variation in aboveground woody biomass. A comparison between modeled and measured leaf litterfall was made at a semi-deciduous Equatorial rainforest site in the Republic of Congo at the Biosphere reserve Dimonika south of Gabon. Also, simulated woody aboveground biomass was compared against site-level field inventories and satellite-based estimates based on a combination of MODIS imagery with field inventory data from Uganda, DRC and Cameroon. First comparison results seem promising and show that the radiation driven leaf litterfall model results correspond well with the field inventories and that the mean of the modelled aboveground woody biomass matches the available field inventory observations but there is still a need for more ground data to evaluate the model outcome over a large region like this.

  11. A Scheme to Improve Throughput for ARQ-Protected Satellite Communication

    NASA Technical Reports Server (NTRS)

    Friedman, Daniel; Ephremides, Anthony

    1997-01-01

    Automatic-repeat-request (ARQ) error control is often employed to assure high fidelity information transmission. However, ARQ error control can provide poor throughput for satellite multicasting. The throughput in such communication may be improved by the combination of a terrestrial network parallel to the satellite network and a judiciously modified ARQ protocol. In particular, retransmitted ARQ frames can be sent terrestrially in such a hybrid network, allowing higher throughput than in a pure-satellite network. This work presents analytic results to establish the potential for improving the throughput of satellite multicast communication employing ARQ error control by the adoption of such a hybrid network architecture.

  12. The Valanginian terrestrial carbon-isotope record

    NASA Astrophysics Data System (ADS)

    Grocke, D. R.; Price, G. D.; Baraboshkin, E.; Mutterlose, J.; Ruffell, A. H.

    2003-04-01

    A stratigraphic, biostratigraphic and isotopic investigation has been performed on a Crimean section located on the Kacha River, Verkhorechie Village, SW Crimea. This clastic-dominated succession consists of a series of bioturbated inter-bedded shallow-marine silty sands, claystones and some oolitic sands. A published detailed study of the ammonite fauna has been undertaken and has revealed that the succession can be compared to standard Tethyan schemes. The lower part of the succession is dated on the basis of the ammonite fauna as Early Valanginian (otopeta-campylotoxus ammonite Zones), although this latter zone is highly condensed. A more expanded Late Valanginian is present (verrucosum, callidiscus and tauricum ammonite Zones), and is overlain by sand-dominated sediments of Early Hauterivian age. Throughout this section woody plant matter ranging in preservation from charcoal to coal has been collected and analyzed for stable carbon-isotope ratios. There is no correlation between state of preservation and carbon-isotope ratios. Carbon-isotope ratios range in the Early Valanginian from -24 ppm to -22 ppm, and in the mid-verrucosum Zone values shift abruptly towards more positive values and peak at -18 ppm in the lower callidiscus Zone. Wood carbon-isotope ratios decrease gradually through the remainder of the callidiscus Zone and return to pre-excursion values in the tauricum Zone. The remaining Hauterivian values fluctuate between -24 ppm to -21 ppm. The structure, magnitude and timing of the terrestrial carbon-isotope curve is very similar to the marine carbonate curve (from +1 ppm to +3 ppm) for the Valanginian. This would indicate, based on a delta-delta relationship between organic matter and carbonate, that there was very little change in atmospheric CO_2 concentrations during the Valanginian, and that the isotopic composition of the global carbon reservoir shifted. Future research on an Early Cretaceous (Valanginian-Hauterivian) interval from the Yatria River, sub-polar Urals, Western Siberia, which contains both belemnites and terrestrial wood fragments will provide another section from which to determine whether the delta-delta relationship for the Valanginian from Crimea is a global phenomenon or that it can be explained via latitudinal variation.

  13. Isotope powered Stirling generator for terrestrial applications

    SciTech Connect

    Tingey, G.L.; Sorensen, G.C. [Pacific Northwest Lab., Richland, WA (United States); Ross, B.A. [Stirling Technology Co., Richland, WA (United States)

    1995-01-01

    An electric power supply, small enough to be man-portable, is being developed for remote, terrestrial applications. This system is designed for an operating lifetime of five years without maintenance or refueling. A small Radioisotope Stirling Generator (RSG) has been developed. The energy source of the generator is a 60 watt plutonium-238 fuel clad used in the General Purpose Heat Sources (GPHS) developed for space applications. A free piston Stirling Engine drives a linear alternator to convert the heat to power. The system weighs about 7.5 kg and produces 11 watts AC power with a conversion efficiency of 18.5%. Two engine models have been designed, fabricated, and tested to date: (a) a developmental model instrumented to confirm and test parameters, and (b) an electrically heated model with an electrical heater equipped power input leads. Critical components have been tested for 10,000 to 20,000 hours. One complete generator has been operating for over 11,000 hours. Radioisotope heated prototypes are expected to be fabricated and tested in late 1995.

  14. Interpretation of our present terrestrial climatic record

    SciTech Connect

    Ellsaesser, H.W.

    1987-09-01

    Detailed studies of profiles of delta/sup 18/O in oceanic and glacial cores and of pollen deposits in bogs indicate that the terrestrial climatic system, consisting of the atmosphere, hydrosphere, lithosphere and biosphere, is capable of oscillations with amplitudes, such as that of the Melisey II stadial of northern France, approaching or equaling that of the glacial-interglacial cycle but on time scales too short for the usually envisioned transfer of mass between the oceans and continental glaciers. Abrupt oscillations or shifts to new equilibrium are well documented in the Boelling-Aleroed warming and Younger Dryas readvance, the 0.4/sup 0/C rise in NH continental air temperature circa 1920 and the year-to-year oscillations in NH continental air temperatures from 1976 to 1984. Such abrupt oscillations defy explanation in terms of external forcing functions and suggest rather internal rearrangements within the climate system as the driving mechanism. Suggestions are made as to mechanisms for possible internal rearrangements which might lead to different hemispheric or global mean surface temperatures.

  15. Energy partitioning dynamics of drying terrestrial surfaces

    NASA Astrophysics Data System (ADS)

    Aminzadeh, Milad; Or, Dani

    2014-11-01

    The dynamics of radiative energy partitioning on drying terrestrial surfaces reflects the strong coupling between evaporation and surface temperature that shapes latent and sensible heat fluxes. We used a new pore-scale analytical model that explicitly links evaporative fluxes with temperature dynamics of drying surfaces. Model predictions were in good agreement with measured evaporation rates and surface temperature variations observed during drying of a homogeneous sand surface. The model was extended to heterogeneous surfaces by considering responses of representative elements of a complex surface and weighing relative contributions to formulate area-averaged fluxes. Notwithstanding the small scale basis of the model, the fully coupled surface energy balance provides a physically-based framework for predicting the Bowen ratio and the Priestley-Taylor ? (Priestley and Taylor, 1972) for a range of boundary conditions using readily available input variables (radiation, air temperature, etc.). Analyses show that ? is not constant (typically assumed as ? = 1.26), it decreases with surface drying and increasing net radiation, and increases with increasing wind speed. The physically-based predictability offers new opportunities for generalization of algorithms that rely on remotely sensed surface temperature to estimate surface fluxes.

  16. Terrestrial Planet Formation Surrounding Close Binary Stars

    E-print Network

    Elisa V. Quintana; Jack J. Lissauer

    2006-07-11

    Disk material has been observed around both components of some young close binary star systems. It has been shown that if planets form at the right places within such disks, they can remain dynamically stable for very long times. Herein, we numerically simulate the late stages of terrestrial planet growth in circumbinary disks around 'close' binary star systems with stellar separations between 0.05 AU and 0.4 AU and binary eccentricities up to 0.8. In each simulation, the sum of the masses of the two stars is 1 solar mass, and giant planets are included. Our results are statistically compared to a set of planet formation simulations in the Sun-Jupiter-Saturn system that begin with essentially the same initial disk of protoplanets. The planetary systems formed around binaries with apastron distances less than ~ 0.2 AU are very similar to those around single stars, whereas those with larger maximum separations tend to be sparcer, with fewer planets, especially interior to 1 AU. We also provide formulae that can be used to scale results of planetary accretion simulations to various systems with different total stellar mass, disk sizes, and planetesimal masses and densities.

  17. Radionuclide transport processes in terrestrial ecosystems

    SciTech Connect

    Whicker, F.W.

    1983-04-01

    Some major principles and the status of knowledge concerning the transport of radionuclides through terrestrial ecosystems are reviewed. Fundamental processes which control the flow of radionuclides between ecosystem components such as air, soil, plants, and animals are described, with emphasis on deposition, resuspension, plant uptake, ingestion, and assimilation. Properties of radionuclides, organisms, and ecosystems are examined in relation to their influence on the accumulation of radioactive materials by plants and animals. The effects of the physicochemical nature of the radionuclide; morphology, physiology, and behavior of the organism; and soil, nutrient, and trophic characteristics of the ecosystem are highlighted. Observations in natural ecosystems on radionuclides such as /sup 137/Cs, /sup 90/Sr, /sup 131/I, /sup 3/H, and /sup 239/Pu are used to illustrate current concepts. An assessment of the degree to which the processes controlling radionuclide behavior are understood and of our ability to simulate and predict such behavior with computerized models is offered. Finally, brief comments are made on research needs.

  18. Dinosaurs and the Cretaceous Terrestrial Revolution.

    PubMed

    Lloyd, Graeme T; Davis, Katie E; Pisani, Davide; Tarver, James E; Ruta, Marcello; Sakamoto, Manabu; Hone, David W E; Jennings, Rachel; Benton, Michael J

    2008-11-01

    The observed diversity of dinosaurs reached its highest peak during the mid- and Late Cretaceous, the 50 Myr that preceded their extinction, and yet this explosion of dinosaur diversity may be explained largely by sampling bias. It has long been debated whether dinosaurs were part of the Cretaceous Terrestrial Revolution (KTR), from 125-80 Myr ago, when flowering plants, herbivorous and social insects, squamates, birds and mammals all underwent a rapid expansion. Although an apparent explosion of dinosaur diversity occurred in the mid-Cretaceous, coinciding with the emergence of new groups (e.g. neoceratopsians, ankylosaurid ankylosaurs, hadrosaurids and pachycephalosaurs), results from the first quantitative study of diversification applied to a new supertree of dinosaurs show that this apparent burst in dinosaurian diversity in the last 18 Myr of the Cretaceous is a sampling artefact. Indeed, major diversification shifts occurred largely in the first one-third of the group's history. Despite the appearance of new clades of medium to large herbivores and carnivores later in dinosaur history, these new originations do not correspond to significant diversification shifts. Instead, the overall geometry of the Cretaceous part of the dinosaur tree does not depart from the null hypothesis of an equal rates model of lineage branching. Furthermore, we conclude that dinosaurs did not experience a progressive decline at the end of the Cretaceous, nor was their evolution driven directly by the KTR. PMID:18647715

  19. Redox Conditions Among the Terrestrial Planets

    NASA Technical Reports Server (NTRS)

    Jones, J. H.

    2004-01-01

    Early solar system conditions should have been extremely reducing. The redox state of the early solar nebula was determined by the H2O/H2 of the gas, which is calculated (based on solar composition) to have been about IW-5. At high temperature under such conditions, ferrous iron would exist only as a trace element in silicates and the most common type of chondritic material should have been enstatite chondrites. The observation that E-chondrites form only a subset of the chondrite suite and that the terrestrial planets (Earth, Moon, Mars, Venus, 4 Vesta) contain ferrous and ferric iron as major and minor elements, respectively, implies that either most chondritic materials formed under conditions that were not solar or that early-formed metals oxidized at low temperature, producing FeO. For example, equilibrated ordinary chondrites (by definition, common chondritic materials), by their phase assemblage of olivine, orthopyroxene and metal, must fall not far from the QFI (Quartz-Fayalite-Iron) oxygen buffer. The QFI buffer is about IW-0.5 and, as we shall see, this fo2 is close to that inferred for many materials in the inner solar system.

  20. Terrestrial Effects of a 30 pc Supernova

    NASA Astrophysics Data System (ADS)

    Thomas, B. C.; Melott, A. L.; Hogan, D. P.

    2005-12-01

    It has been suggested by several authors (e.g. Ruderman 1974; Reid et al. 1978; Ellis & Schramm 1995) that a relatively nearby supernova (SN) explosion could have significant effects on life on the Earth. A primary terrestrial effect of such an encounter would be depletion of the ozone layer, thereby increasing the flux of solar UVB radiation at the Earth's surface. At least one quantitative study of the effects on ozone by SN at various distances has been conducted (Gehrels et al. 2003). There is direct geochemical evidence for at least one SN event at a distance of around 40 pc at about 2.8 Myr ago (Fields 2004; Knie et al. 1999, 2004; Benitez et al. 2002). In this work we examine a suite of effects of such a SN at a distance of 30pc. We investigate ozone depletion, the subsequent increase of solar UVB reaching the Earth's surface, and the biological impact of this increased UVB. We find maximum localized ozone column density depletion of about 10% lasting a few months, an increase of around 1% in UVB irradiance in certain locations, and about 5% increase in relative DNA damage. While this level of effect is unlikely to be responsible for a large scale die-off, increases in the mutation rate are likely, possibly with interesting evolutionary or ecological implications. This work is supported in part by NASA Astrobiology grant NNG04GM41G.

  1. International Solar-Terrestrial Physics Science Initiative

    NSDL National Science Digital Library

    The National Aeronautics and Space Administration (NASA), the European Space Agency (ESA), and the Institute of Space and Astronautical Science (ISAS) of Japan have collaborated to make available the International Solar-Terrestrial Physics (ISTP) Science Initiative. The ISTP Science initiative has five primary objectives. For example, the initiative seeks to "determine structure and dynamics in the solar interior and their role in driving solar activity." Sections included at the Website are What is the Sun-Earth Connection, Mission Connection, and What's New. Furthermore, the What is the Sun-Earth Connection section is subdivided into sections such as What is Geospace (the space in between the Earth and the Sun), Studying the Invisible Realm, and Hot Pics and Cool Movies. Spectacular colorful images of Northern and Southern Lights from Earth and Space, Sun Spotting, Images of Earth from Space, Space Weather, and movies showing comets flying into the sun, solar eclipses, and solar tornadoes are presented in the Hot Pics and Cool Movies section.

  2. Refined approaches for terrestrial reference frame computations

    NASA Astrophysics Data System (ADS)

    Meisel, B.; Angermann, D.; Krügel, M.; Drewes, H.; Gerstl, M.; Kelm, R.; Müller, H.; Seemüller, W.; Tesmer, V.

    Recent solutions of the terrestrial reference frame such as ITRF2000 are combined from multi-year data sets that contain station positions at a reference epoch and constant velocities. Analysis of time series of station positions of the geodetic space techniques SLR, GPS, VLBI and DORIS show, however, that these techniques allow to detect variations in station position series with up to a few millimetre accuracy. Therefore, the underlying reference frame needs to assure the same accuracy. In this paper we analyse systematic effects in station position and transformation parameter time series that need to be taken into account for future TRF realisations. These are mainly annual signals that show up as common variations of the global networks as well as local effects on individual stations. These annual signals differ significantly from technique to technique for some co-location sites. Apart from periodic signals the time series show discontinuities (e.g. due to earthquakes or instrumentation changes) and periods of non-linear motion (e.g. post-seismic relaxation). We compute TRF technique solutions of five years of epoch normal equations, which allows to adapt the parameterisation in order to account for the effects mentioned above. The accuracy of the technique-specific solutions is evaluated by comparing the results at co-location sites. For this purpose, we transform the VLBI, SLR and DORIS solutions to the GPS solution by using the measured local ties between GPS and the other techniques.

  3. Refined approaches for terrestrial reference frame computations

    NASA Astrophysics Data System (ADS)

    Meisel, B.; Angermann, D.; Drewes, H.; Gerstl, M.; Kelm, R.; Kruegel, M.; Mueller, H.; Tesmer, V.

    Geodetic space techniques allow to determine station positions with precisions of a few millimeters. The underlying reference frame requires thus the same level of accuracy. The International Terrestrial Reference System (ITRS) is up to date realised by epoch positions and linear velocities for all the included stations. Detailed analyses, however, show that linear velocities do not fit the time dependent positions with the required accuracy. To improve the time evolution we study weekly solutions of the station positions and datum parameters. We use GPS, SLR, VLBI and DORIS solutions that are obtained from the corresponding IERS technique centres or computed at DGFI. Time series of station coordinates and datum parameters (scale, translation) are computed by aligning each individual solution to a multi-year reference (ITRF2000). The time series are analysed to detect systematic effects such as jumps or periodic signals (esp. seasonal periods). Additionally the covariance information of the networks and the station positions are investigated. As a refined approach we then combine the weekly normal equations to a multi-year TRF solution. Thereby an important aspect is the parameterisation (e.g. to include an annual period for station positions and the datum parameters). The results are discussed and compared with existing TRF solutions and geophysical models.

  4. Observing Strategies for the Terrestrial Planet Finder

    NASA Astrophysics Data System (ADS)

    Heap, S. R.; Lindler, D. J.

    2004-12-01

    The primary objectives of the Terrestrial Planet Finder Coronagraph (TPF-C) are to survey at least 35 nearby main-sequence stars in search of earth-like planets, and if found, to characterize them. TPF-C is unusual in that the target is not a specific object but a circumstellar region, the ``habitable zone'' = 0.7-1.5 Lbol.5 AU, which may contain several planets whose positions and (phase-dependent) brightnesses are constantly changing. In order to explore observing strategies for TPF-C, one of us (DJL) has developed a visual software tool called {\\textit tpf_planner} that enables the user to try out different approaches. We have used {\\textit tpf_planner} to simulate observations of about 50 likely TPF-C target stars. Some preliminary results include: \\begin{itemize} Planets are easier to detect around late-type stars than around early-type stars; Surveys of late-type stars can be accomplished in one observing season (6 months), whereas surveys of early-F stars could take up to four years; Many stars require only 3 visits to survey at least 90% of the habitable zone; Exo-zodi background is often the limiting factor for planet detection, but CCD read noise is usually the limiting factor for spectroscopy. The development of {\\textit tpf_planner} was funded by the TPF project. The software, which runs under most operating systems, is freely available. Please contact lindler@rockit.gsfc.nasa.gov.

  5. Communicating Science

    NASA Astrophysics Data System (ADS)

    Holland, G. J.; McCaffrey, M. S.; Kiehl, J. T.; Schmidt, C.

    2010-12-01

    We are in an era of rapidly changing communication media, which is driving a major evolution in the modes of communicating science. In the past, a mainstay of scientific communication in popular media was through science “translators”; science journalists and presenters. These have now nearly disappeared and are being replaced by widespread dissemination through, e.g., the internet, blogs, YouTube and journalists who often have little scientific background and sharp deadlines. Thus, scientists are required to assume increasing responsibility for translating their scientific findings and calibrating their communications to non-technical audiences, a task for which they are often ill prepared, especially when it comes to controversial societal issues such as tobacco, evolution, and most recently climate change (Oreskes and Conway 2010). Such issues have been politicized and hi-jacked by ideological belief systems to such an extent that constructive dialogue is often impossible. Many scientists are excellent communicators, to their peers. But this requires careful attention to detail and logical explanation, open acknowledgement of uncertainties, and dispassionate delivery. These qualities become liabilities when communicating to a non-scientific audience where entertainment, attention grabbing, 15 second sound bites, and self assuredness reign (e.g. Olson 2009). Here we report on a program initiated by NCAR and UCAR to develop new approaches to science communication and to equip present and future scientists with the requisite skills. If we start from a sound scientific finding with general scientific consensus, such as the warming of the planet by greenhouse gases, then the primary emphasis moves from the “science” to the “art” of communication. The art cannot have free reign, however, as there remains a strong requirement for objectivity, honesty, consistency, and above all a resistance to advocating particular policy positions. Targeting audience attitudes and beliefs, which studies such as the Six Americas research help identify, is key to effective science communications (e.g. Leiserowitz, Maibach, et al, 2009). We argue that the impact of the scientific message can be substantially improved by targeting it to these additional factors. This does require an understanding of the audience and a repackaging of the message to different societal groups. Logical and dispassionate presentation of evidence works for a target scientific audience, but major decisions from the policy to the personal level are influenced by many factors including immediacy, economics, culture, community leaders, emotional framing, and ideological filters.

  6. FATE OF SELECTED FUNGICIDES IN A TERRESTRIAL LABORATORY ECOSYSTEM

    EPA Science Inventory

    The disposition of (14)C-labeled pentachloronitrobenzene (PCNB), two of its analogues pentachlorophenol (PCP) and hexachlorobenzene (HCB), and captan was examined as seed-protectant coatings in a terrestrial microcosm chamber (TMC) in comparison to a reference compound, dieldrin ...

  7. Estimating terrestrial amphibian pesticide body burden through dermal exposure

    EPA Science Inventory

    Dermal exposure presents a potentially significant but understudied route for pesticide uptake in terrestrial amphibians. Our study measured dermal uptake of pesticides of varying hydrophobicity (logKow) in frogs. Amphibians were indirectly exposed to one of five pesticide active...

  8. Terrestrial runoff influences white syndrome prevalence in SW Madagascar.

    PubMed

    Sheridan, C; Baele, J M; Kushmaro, A; Fréjaville, Y; Eeckhaut, I

    2014-10-01

    Terrestrial runoff and sedimentation have been implicated in a variety of impacts on scleractinian corals. However, despite accumulating evidence, little work has been done to investigate their influence on coral disease development. This study examined the role that river runoff and the associated sedimentation could play in affecting the prevalence of the coral disease "white syndrome" in SW Madagascar. Corals from reefs affected by river discharge and terrestrial sediments were more affected by white syndrome than reefs located far from any source of terrestrial runoff. Terrestrial runoff-affected reefs also displayed a wider diversity of coral species affected by this disease. While much evidence has been pointing in the direction of indirect effects of such runoff on coral disease development, our data corroborates earlier suggestions that pathogens are present within the sediments. As such, sediments released on reefs through river discharge could act as reservoirs of coral pathogens. PMID:25218232

  9. Draft genomes of gammaproteobacterial methanotrophs isolated from terrestrial ecosystems.

    PubMed

    Hamilton, Richard; Kits, K Dimitri; Ramonovskaya, Victoria A; Rozova, Olga N; Yurimoto, Hiroya; Iguchi, Hiroyuki; Khmelenina, Valentina N; Sakai, Yasuyoshi; Dunfield, Peter F; Klotz, Martin G; Knief, Claudia; Op den Camp, Huub J M; Jetten, Mike S M; Bringel, Françoise; Vuilleumier, Stéphane; Svenning, Mette M; Shapiro, Nicole; Woyke, Tanja; Trotsenko, Yuri A; Stein, Lisa Y; Kalyuzhnaya, Marina G

    2015-01-01

    Genome sequences of Methylobacter luteus, Methylobacter whittenburyi, Methylosarcina fibrata, Methylomicrobium agile, and Methylovulum miyakonense were generated. The strains represent aerobic methanotrophs typically isolated from various terrestrial ecosystems. PMID:26044417

  10. ECOSYSTEM ECOLOGY -ORIGINAL PAPER Increasing donor ecosystem productivity decreases terrestrial

    E-print Network

    Rosemond, Amy Daum

    ECOSYSTEM ECOLOGY - ORIGINAL PAPER Increasing donor ecosystem productivity decreases terrestrial Abstract Because nutrient enrichment can increase ecosystem productivity, it may enhance resource flows to adjacent ecosystems as organisms cross ecosystem bound- aries and subsidize predators in recipient

  11. Draft Genomes of Gammaproteobacterial Methanotrophs Isolated from Terrestrial Ecosystems

    PubMed Central

    Hamilton, Richard; Kits, K. Dimitri; Ramonovskaya, Victoria A.; Rozova, Olga N.; Yurimoto, Hiroya; Iguchi, Hiroyuki; Khmelenina, Valentina N.; Sakai, Yasuyoshi; Dunfield, Peter F.; Klotz, Martin G.; Knief, Claudia; Op den Camp, Huub J. M.; Jetten, Mike S. M.; Bringel, Françoise; Vuilleumier, Stéphane; Svenning, Mette M.; Shapiro, Nicole; Woyke, Tanja; Trotsenko, Yuri A.; Stein, Lisa Y.

    2015-01-01

    Genome sequences of Methylobacter luteus, Methylobacter whittenburyi, Methylosarcina fibrata, Methylomicrobium agile, and Methylovulum miyakonense were generated. The strains represent aerobic methanotrophs typically isolated from various terrestrial ecosystems. PMID:26044417

  12. High Efficiency, High Density Terrestrial Panel. [for solar cell modules

    NASA Technical Reports Server (NTRS)

    Wohlgemuth, J.; Wihl, M.; Rosenfield, T.

    1979-01-01

    Terrestrial panels were fabricated using rectangular cells. Packing densities in excess of 90% with panel conversion efficiencies greater than 13% were obtained. Higher density panels can be produced on a cost competitive basis with the standard salami panels.

  13. Remote sensing of terrestrial tropospheric aerosols from aircraft and satellites

    E-print Network

    Remote sensing of terrestrial tropospheric aerosols from aircraft and satellites M I Mishchenko1;74 particles produced by volcanos or as a result of burning sulfur-bearing fossil fuels reflect the solar

  14. Methodology for assessing coastal change using terrestrial laser scanning

    E-print Network

    Olsen, Michael James

    2009-01-01

    Dates and times are Coordinated Universal Time (and times are Coordinated Universal Time (UTC). Figure 5-9.Time Terrestrial Laser Scanning/Scanner Topographical Compartment Analysis Tools custom VBA routines in GIS software Torrey Pines Total Water Level Universal

  15. A New Photochemistry Code for Terrestrial Exoplanet Atmospheres

    E-print Network

    Johnson, Robert E.

    A New Photochemistry Code for Terrestrial Exoplanet Atmospheres Renyu Hu, Sara Seager Massachusetts Institute of Technology Renyu Hu, 2012, UVa Workshop Page 1 #12;Photochemistry Model · 1-D chemistry

  16. Visualizing Terrestrial and Aquatic Systems in 3D

    EPA Science Inventory

    The need for better visualization tools for environmental science is well documented, and the Visualization for Terrestrial and Aquatic Systems project (VISTAS) aims to both help scientists produce effective environmental science visualizations and to determine which visualizatio...

  17. Why Communicate

    NASA Astrophysics Data System (ADS)

    Illingworth, Samuel

    2015-04-01

    "Half the world is composed of people who have something to say and can't, and the other half who have nothing to say and keep on saying it." - Robert Frost In this age of digital soap boxes and half-truths, the importance of geoscientists as communicators cannot be underestimated, nor has there been a more important time for researchers to stand up and demand to be heard. So why is there still such an overwhelming public perception that scientists are poor communicators, and what can we do to change this? In this work I will present an overview of a number of successful initiatives that have been developed at Manchester Metropolitan University, and beyond, to ensure that science is communicated to a large variety of people, from policy makers to members of the local community. I will also present an overview of the emerging field of Science Communication, how it has changed in the past few decades from a one-way diatribe to a two-way discussion, and how this represents a possible new direction and career path for geoscientists. Anne Roe, the noted American psychologist, told us, "nothing in science has any value to society if it is not communicated." As geoscientists, we have a professional and moral obligation to ensure that we not only research the facts, but that we also present them in an informative and engaging manner, so that the rest of humanity can benefit from the fruits of our labour.

  18. Corporate strategies for satellite communications

    NASA Astrophysics Data System (ADS)

    Birch, David G. W.; Buck, S. Peter

    1991-10-01

    Terrestrial and satellite broadcast communications technologies, while clearly providing tremendous benefits in many market sectors, present something of a challenge to the strategic planning bodies in most organizations. This is because there is no existing analog for the services in the organizations' telecommunications networks. The marketplace is therefore a confusing place for such organizations swamped as it is with competing service providers, technologies, and services, and their telecommunications strategies cannot cope with the opportunities because they have been founded on the exploitation of point to point connections. A mechanism for creating and bounding strategies which combines the rigor of structured analysis with a comprehensive categorization of strategic directions which has been successfully used to generate new paneuropean telecommunications strategies is presented.

  19. Contributions of SCADM to solar-terrestrial physics

    NASA Technical Reports Server (NTRS)

    Fisk, L. A.

    1980-01-01

    The many different aspects of solar terrestrial physics are summarized. The possible influence of variations in the solar outputs on the terrestrial climate, and the role for SCADM in such studies is emphasized. The use of SCADM to provide detailed information on variations in the solar outputs over a sizeable fraction of the solar cycle, and on the physics of the convection layer of the Sun is discussed.

  20. AUTOMATED 3-D FEATURE EXTRACTION FROM TERRESTRIAL AND AIRBORNE LIDAR

    Microsoft Academic Search

    D. W. Opitz; R. Rao; J. S. Blundell

    ABSTRACT: The U.S. Army and other Department of Defense (DoD) combat and combat support agencies requires automated feature extraction (AFE) software for collecting very high-resolution 3D urban features from terrestrial LIDAR data to support the ground-based Warfighter operating in the urban battlespace. Advanced,vehicle-mounted and man-portable terrestrial Light Imaging and Range Detection (LIDAR) systems capture accurate 3D measurements,of the urban environment